A coated imageable semiconductor is imaged by heating an area of the coating with an infrared laser and reacting the coating in the heated area with ultraviolet or visible radiation. The coating can be either positive working or negative working. The modulated radiation may either be the ultraviolet/visible radiation or the infrared radiation and the radiation spots are superimposed or the ultraviolet/visible spot may closely trail the infrared spot. The imaging time is reduced since the reaction rate is increased at the elevated temperature.

The present invention relates to the imaging of a plate or planar surface having a coating imageable by ultraviolet or visible radiation and more specifically to actinic imaging with simultaneous heating to improve the imaging process. The invention of this application is particularly directed to the imaging of semiconductors.
One type of imageable plate is a negative-working, actinic plate which has a resin coating normally soluble in a developer and which is rendered insoluble when exposed to radiation, usually in the ultraviolet range. The plate is imaged by exposing the coating to the radiation in those areas corresponding to the image to be printed with those areas becoming insoluble and ink receptive. Another type of imageable plate is a positive-working plate which is also actinically imaged. This type of plate has a resin coating normally insoluble in a developer which is rendered soluble when exposed to the radiation.
Actinic imaging, whether it be by ultraviolet radiation or by visible radiation, can be accomplished by one of two techniques. One technique is to expose the plate through a film negative. The other approach is to serially scan the plate with small image spots or areas. This latter approach can be accomplished by digital laser imaging or by a method referred to as digital screen imaging which will be explained later. Although digital screen imaging is not digital imaging in the strictest sense of that term as will be explained, the term xe2x80x9cdigitalxe2x80x9d will be used herein to encompass both the digital laser imaging and the digital screen imaging which both involve imaging by serially scanning the plate with small areas or spots of the imaging radiation.
An object of the present invention is to provide an improved actinic imaging method for either negative-working or positive-working plates or planar surfaces and particularly for semiconductors hereinafter all referred to as plates. The invention involves the imaging of the semiconductor to cause a reaction in the coating in the exposed areas by actinic imaging using either ultraviolet or visible radiation in combination with infrared radiation. The reaction may either solubilize or insolubilize the coating depending on whether the plate is positive- or negative-working. The infrared radiation operates to increase the localized temperature of the coating to a level at which the rate of the actinic imaging reaction is increased. Either the ultraviolet/visible radiation or the infrared radiation can be image modulated. The relative areas covered by the ultraviolet/visible radiation and by the infrared radiation can be varied such that the areas are superimposed or that the area of the ultraviolet/visible radiation closely trails the infrared area.
The invention relates to the imaging of plates or planar surfaces with imageable coatings and particularly to the imaging of semiconductors. The production of semiconductors has usually been performed by adopting the imaging techniques used in the production of lithographic printing plates using imageable resist compositions. The resolution of these imaging techniques can be improved by shortening the wavelength of the exposure radiation in order to limit diffraction.
Accordingly, the wavelengths of the radiation used for semiconductor production have become shorter and shorter. For example, a KrF excimer laser at a wavelength of 248 nm or a ArF excimer laser at a wavelength of 193 nm can be used to obtain higher resolutions. However, since lenses in equipment using ArF excimer lasers have a shorter lifetime, it is advantageous to shorten the exposure time required for imaging. The invention will be described with reference broadly to plates but it is to be understood that the description applies to semiconductors.
Plates with coatings which are imageable by ultraviolet or visible radiation wherein the radiation causes an insolubilizing reaction in the coating for negative-working plates and a solubilizing reaction for positive-working plates are well known. Typically, the insolubilizing reaction for negative-working plates is a crosslinking or photopolymerization reaction but other chemical changes may also insolubilize the coating and are within the scope of the invention. The insolubilized imaged areas become the ink-receptive plate areas and the non-imaged areas are removed with a typical developer solution. The coatings for such plates are well known in the art and are typically a diazo resin having reactive sites which are capable of being chemically altered by the radiation. A suitable diazo resin is the condensation product of 3-methoxy-4 diazo-diphenylamine and paraformaldehyde. Other suitable diazo compounds are described in a variety of prior patents including U.S. Pat. Nos. 5,998,095; 4,956,261; 3,406,159; 3,277,074; 3,311,605; 3,163,633 and 3,050,502. For positive-working plates, the coatings are normally insoluble in the developer solution and are solubilized in the areas exposed to the imaging radiation. Such coatings are well known and usually comprise a diazide, such as diazonaphthoquinone derivatives, mixed with or reacted with a phenolic resin. For a specific disclosure of diazonaphthoquinone derivatives, see U.S. Pat. No. 5,858,626. The mechanism of such coatings is described in the article, xe2x80x9cThe Molecular Mechanism of Novolak Resinsxe2x80x9d by Arnost Reiser appearing in the Journal of Imaging Science and Technology, Volume 42, No. 1, January/February 1998 on pages 15 to 22.
Plates may be imaged by digital laser imaging and by digital screen imaging. The invention will first be described with respect to digital laser imaging and the digital screen imaging will be described later. Also, the invention will be described with respect to negative-working plates with coatings which are insolubilized by the radiation but it is to be recognized that the invention applies equally to positive-working plates with coatings which are solubilized by the radiation. Furthermore, the invention is applicable to imaging radiation with a wavelength shorter than infrared. For convenience purposes, ultraviolet radiation or devices will be referred to but it is to be understood that the imaging radiation of the invention includes visible as well as ultraviolet radiation. For example, blue or violet diode lasers or a double frequency YAG laser at 532 nm can be used. Like most chemical reactions, the rate at which the solubility conversion takes place for the actinic digital imaging of a lithographic plate is dependent on the temperature. The rate of reaction is slower at ambient conditions than at elevated temperatures. By elevating the temperature at which the imaging is done, the speed of the imaging process can be increased. It is problematic to increase the temperature of the entire plate by elevating the temperature of the imaging platen or drum. The thermal expansion of the components of the imager and the dynamics of managing the heat flow to the plate in a timely and uniform manner make this approach impractical.
According to the present invention, the temperature of the resin coating is increased to enhance the reaction but it is only locally and momentarily heated and heated generally simultaneously with the imaging. The invention involves spot heating the coating with an infrared laser and subjecting the coating while it is heated to the ultraviolet radiation to react the coating at the elevated temperature. The coating is not reacted or otherwise imaged by the infrared radiation but the infrared radiation interacts with the coating and/or substrate merely to heat the coating. Either the ultraviolet radiation or the infrared radiation can be image modulated as discussed below. If desired, an infrared absorbing dye may be incorporated into the coating to facilitate the infrared absorption and heating. These dyes are well known in the art and include materials such as squarylium, croconate, cyanine, phthalocyanine, merocyanine, chalcogenopyryloarylidene, orzindollizine, puinoid, indolizine, pyrylium, thizine, azulenium and xanthene dyes. The infrared heating of the coating can also be effected by using a substrate having infrared absorption characteristics. For example, an anodized aluminum substrate which has been rotary brush grained with calcined alumina so as to embed the graining particles to cover a portion, perhaps 10%, of the surface of the substrate will effect the rate of heat absorption by the substrate and the conduction of heat away from the spot by the aluminum. The power and intensity of the infrared laser as well as the dye in the coating and the nature of the substrate can be selected to instantaneously increase the coating temperature to enhance the coating reaction by increasing the reaction kinetics. The effect of the coating temperature on the reaction kinetics is progressive, i.e. the higher the temperature, the faster the reaction. Therefore, any temperature increase will have some effect but the preferred coating temperature range is 250 to 400xc2x0 F. With the higher coating temperature, much less power or time is required to trigger the reaction. Specifically, with respect to ultraviolet radiation, imaging can be accomplished with much less powerful gas lasers or with a diode or semiconductor ultraviolet laser in the power range of one watt or less. Therefore, the lasers are much less expensive, require less power input, do not require water cooling and are easier to modulate. The ultraviolet radiation is usually in the range of 340 to 390 nm.
In the practice of the invention, either the infrared radiation or the ultraviolet radiation may be image modulated. With modulated ultraviolet radiation, the unmodulated infrared radiation heats an area of the coating which is simultaneously imaged with superimposed modulated ultraviolet radiation. The spot of modulated ultraviolet radiation can be smaller than or the same size as the spot of infrared radiation. Alternately, the modulated spot of ultraviolet radiation can closely trail the unmodulated spot of infrared radiation with the criteria being that the coating is still hot at the time it is subjected to the ultraviolet radiation. With modulated infrared radiation, an area of the coating is exposed to a relatively low level of unmodulated ultraviolet radiation and that spot is simultaneously exposed to the superimposed modulated infrared radiation. The infrared spot is either the same size or smaller than the ultraviolet spot. The level of ultraviolet radiation is low enough that it will not significantly react the coating at ambient temperature during the short exposure time. It is only because of the simultaneous heating that the ultraviolet radiation is sufficient to react the coating in the heated image pattern formed by the infrared radiation.
In order to locally heat the coating and simultaneously image, the spots on the plate from the infrared laser and the digital imager must be located such that the imaging is effected while the coating is hot. This usually requires that the spots be superimposed although the ultraviolet spot may closely trail the infrared spot as noted earlier. Although the spots can be the same size, in order to facilitate superimposition and taking into consideration the ability to aim and focus the lasers, one spot is preferably larger than the other with the small spot being entirely within the bounds of the larger spot. The small spot is the modulated radiation whether that be ultraviolet or infrared. Because this ultraviolet imaging is a progressive process (rather than a threshold process) in which exposure of the coating to moderate levels of the ultraviolet radiation could produce some imaging, the ultraviolet spot is usually the modulated imaging radiation and is the smaller of the two spots with the ultraviolet spot being fully contained within the bounds of the infrared spot. Merely as an example, the large infrared spot may have a diameter of 50 microns while the small digital image spot has a diameter of 10 microns. If the infrared radiation is the modulated radiation, the infrared spot will be the smaller and the level of the ultraviolet radiation is kept quite low so that any coating reaction caused solely by the unmodulated ultraviolet radiation is minimal and insufficient to produce an effective image. Although this description of the invention only contemplates a single pair of infrared and ultraviolet lasers, there can simultaneously be multiple infrared and ultraviolet lasers.
Another method of imaging within the scope of the present invention is by a digital screen imaging system such as marketed by basysPrint Corp. This system uses a radiation source which is usually an ultraviolet light source that passes through a condenser system onto a digital screen. This screen has a grid with hundreds of thousands of dots that can each be individually electronically controlled. This produces a digital image on the screen that is projected onto the printing plate. It can be seen that it is the screen image that is digital whereas the image on the plate is a projected image from that digital screen. However, as previously stated, this imaging technique is encompassed with the scope of the digital imaging of this invention. Because of the size of the digital screen, only a segment of the plate is imaged in a single exposure. The segments range in size from 0.3 cm2 to 2.5 cm2 and can be projected at the rate of about 10 segments per second. The exposure head is moved or scanned over the plate to fit the segments together and produce the entire image on the plate. With this type of digital imager, one or more infrared lasers are positioned off to the side and aimed at an angle to focus on the area beneath the digital screen.
The imaging of the invention may be practiced on any conventional imaging equipment such as flat bed imagers, internal drum imagers and external drum imagers. In order to establish the principal and effectiveness of the present invention and the benefits achieved when imaging a coating at an elevated temperature, conventional plates with ultraviolet imageable coatings were heated to bring the coated plates up to a selected temperature. The heated plates were then imaged with ultraviolet light. The results were compared to unheated plates and to plates which had been heated but cooled prior to imaging.

Method of actinically imaging a semiconductor


A catheter body includes a coil body (10) which is formed by winding or stranding metal wires (12) and having a distal portion (16) and a proximal portion. The distance between coils (12) adjacent to each other in the distal portion (16) is greater than the distance between coils (12) adjacent to each other in the proximal portion (18 or 14). The pitch in the distal portion (16) of the coil body (10) is substantially or nearly the same as the pitch in the proximal portion (18 or 14).

1. Field of the Invention
The present invention relates to an improved catheter having a catheter body comprising a coil body, as well as a method of producing such catheter in a favorable manner.
2. Description of the Related Art
Catheters have been known as medical apparatuses that are used via insertion into blood vessels, gastrointestinal tracts, urinary tracts and other tubular organs and tissues of humans. As one type of these catheters, those having its main body, or part inserted into the human body, comprising a coil body formed by winding or stranding long, thin round metal wires are known (such as the one disclosed in Japanese Patent Laid-open Publication No. 2004-242973). For example, these catheters are favorably used in procedures that are performed to dilate an occluded area in a blood vessel.
Specifically, when performing a procedure using one of these catheters having a coil body as the catheter body, generally a guide wire is inserted into the occluded area. Then, the coil body is guided by the guide wire into the occluded area. The coil body dilates the occluded area and forms a somewhat large channel in the occluded area. Next, a relatively small balloon catheter is inserted into the aforementioned channel, after which the balloon is inflated to expand the occluded area further. After this process, a larger balloon catheter may be inserted and inflated, if necessary, to expand the occluded area further. This ensures a sufficient blood flow through the applicable blood vessel.
In these procedures, the aforementioned catheters exhibits excellent operation performance in blood vessels based on the sufficient flexibility and good torque transmissibility of their coil bodies. This is why the bodies of these catheters can be smoothly inserted into blood vessels without damaging the interior walls of the blood vessels. These catheter bodies also allow an occluded area to be dilated in a reliable, easy manner to a sufficient size at which a balloon catheter can be inserted.

Catheter and method of producing the same


The invention relates to a device for transferring to a surface correcting material supplied on a tape-like carrier, provided with a housing comprising a rotatable supply reel for the carrier with the correcting material, a rotatable take-up reel for the carrier after transfer of the material, a transfer member for placing on the surface and along which the carrier with the material is guided, and displaceable means for covering the transfer member. Inadvertent transfer of material when the device is not in use is hereby prevented. The covering means is operable by an operating member which protrudes out of a wall of the housing. The covering means can comprise a displaceable slide, which can take an at least partially flexible form.

1. Field of the Invention
This invention relates to a device for transferring a layer of a material, such as a correction material, from a tape-like carrier to a surface.
2. Description of the Prior Art
Known devices for transferring to a surface a layer of material, for instance correcting material, supplied on a tape-like carrier, include a housing with a rotatable supply reel for the carrier with the material for transferring, a rotatable take-up reel for the carrier after transfer of the material, a transfer member protruding from the housing through a first opening for placing on the surface and along which the carrier with the material is guided, and means for covering the transfer member, said covering means being displaceable between a first position leaving the transfer member free and a second position covering the transfer member. Such a device, which is referred to as a correction roller, is known from DE-A-196 11 440.
With such a correction roller a strip of self-adhesive correcting material can be applied to a surface, for instance to conceal relatively large writing errors. It is then possible to write normally on the correcting material. In the known correction roller the material is arranged on a tape-like carrier which is wound onto a supply reel and guided along the transfer member or the xe2x80x9cfootxe2x80x9d to a take-up reel. The take-up reel and supply reel are both accommodated rotatably in a housing or frame to which the foot is also fixed, and are connected by means of a coupling so that a rotation of the one reel results in a corresponding rotation of the other reel. In order to compensate differences in the rotation speed resulting from differences in the thickness of the reels, the coupling is usually embodied as a slip coupling. For use the correction roller is simply pressed with its foot onto the surface and subsequently moved therealong, whereby the tape-like carrier with correcting material is unwound from the supply reel as a consequence of the friction. The supply reel rotates, whereby the take-up reel is also rotated and the carrier is wound thereon. Because there is less adhesion between the correcting material and the carrier than between the correcting material and the surface, the correcting material remains behind on the surface.
In conventional correction rollers the foot always protrudes outside the housing. This has the consequence that when the correction roller is not in use there is the danger of the correcting material unintentionally adhering to for instance the clothing of the user. In order to obviate this danger it had already been proposed to arrange a releasable cap over the foot which can be removed prior to use. Such a cap was found in practice not to function properly because it often got lost.
The above-identified prior art document DE-A-196 11 440 already discloses a correction roller having a covering member that is slideably arranged in the housing of the roller. Making use of a covering member connected to the housing prevents this being lost, so that a good protection of the foot is ensured in all circumstances when the correction roller is not in use. This prior art covering member, which surrounds the foot, is cylindrical and in its rest position partially protrudes from the housing through the same opening as the foot. For displacing the covering member from its position of rest to its operative position, the user must grip and pull the end part of the covering member. This implies an awkward movement, which cannot be performed single-handedly.
The invention therefore has for its object to provide a device of the above described type which is improved from an ergonomical point of view, and which is thus easier to handle. This is achieved according to the invention in such a device by an operating member connected to the covering means and protruding from a second opening arranged in a wall of the housing. Since the operating member is thus accessible through a wall of the housing, the covering means are easy to operate with the same hand that holds the roller, which allows an ergonomically favorable roller design to be obtained.
In a structurally relatively simple embodiment of the invention which is very practical in use, the covering means comprise a slide.
Advantageously, the operating member herein protrudes out of the housing through a slot extending in the displacement direction of the slide, whereby an additional guiding for the slide is created and the stroke of the slide can be bounded by the ends of the slot.
When the operating member is fixed from the outside of the housing to the covering means, the is dimensions thereof do not have to be limited to the width of the slot, thereby enabling an ergonomically optimal operating member.
In its covering position the covering slide preferably defines a support surface together with a part of the housing. The device can thus be put aside easily when not in use.
When the covering slide is at least partially flexible, it can be guided in simple manner along the inner side of the wall of the housing, thereby achieving a large measure of freedom in the design and placing of the slide. The slide can herein be embodied such that in its covering position it at least partially encloses the transfer member, thus achieving optimum protection of the transfer member.


A composition useful for moisturizing skin which comprises

Skin moisturization has been a desired skin benefit for many years. Dry skin can be a result of environmental effects such as sunlight, dry winter air, dermatological condition as well as the application of cleansing materials to the skin such as soap or other harsh detergents which remove oils that are naturally present on the surface of the skin thereby resulting in a loss of moisturization.
Often times the active ingredients used for the improvement of hair structure and skin surface are usually cationic surfactants in combination with various wax-type additives such as, for example, vaseline, fatty acid esters and fatty alcohols. According to WO 96/27363, however, hair and skin treatment agents on that basis, though, have satisfactory results only in the treatment of dry and porous hair, or dry and porous skin. This document then states that for the treatment of hair/skin that quickly replenishes the fat, they are not as well suited because when they are used, the natural fat replenishment is even increased. The document states the reasons for the strong replenishment of fat are especially the cationic emulsifiers contained in these agents. The document states that it was its task to make available a hair and/or skin treatment agent on the basis of conditioning active ingredient which does not have the disadvantages mentioned. Thereafter, the application discloses a cosmetic agent containing water and a combination of:
a. 0.1 to 25% by weight, of at least one choline salt of an inorganic acid or an organic carboxylic acid or a polyacrylic acid homo- or copolymer, and
b. 0.1 to 10% by weight, of at least one physiologically compatible aliphatic organic acid.
It is then stated that the agent in accordance with the invention improves the ability of the hair to be combed wet, shows good compatibility with the scalp, and gives the hair a soft feel and a beautiful shine. It is further stated that the agent in accordance with the invention shows good compatibility with the skin and the eyes, gives the skin a well-groomed appearance, and is also biodegradable.
There is no information provided in the document as to the specific action of the choline salt on skin other than it xe2x80x9cgives the skin a well groomed appearancexe2x80x9d. Example 5 of the document, a shampoo for hair and skin, states that the skin shows a smooth, soft skin surface after use. Example 6, a skin care cream, states that the skin feels smoother and supple after use. Example 7, an oil in water body lotion, states that the composition increases skin moisture and leaves a pleasant feeling. Present in Example 7 with 7 wt % of choline salts are also 10 wt % cetylstearyloctanoate, 5 wt % glycerine, 4 wt % cetylstearylalcohol, 3 wt % sorbitan stearate, and 1 wt % dimethyl polysiloxane. These latter materials are all well known moisturizing agents.
Nowhere in WO 96/27363 is there a clear definition of what xe2x80x9cconditioningxe2x80x9d agent means. Conditioning in general means making skin feel soft and smooth. A conditioning agent does not necessarily bring about moisturization. Such an agent is generally known as a moisturizing agent. Sometimes these two activities are broadly grouped under the category of xe2x80x9cconditioning and moisturizingxe2x80x9d agent.
We have now discovered that choline salt and related compounds are powerful moisturizing agents for skin. Even in a rinse off cleansing composition such material(s) or mixture thereof brings about substantially more moisture on the skin. This can be a statistically significant measurable quantity of moisture on the skin.
In accordance with the invention, there is a cosmetic composition comprising
a. a moisturizing effective amount of a compound of the formula
wherein X is selected from the group consisting of:
CH2OH, CH OH CH2 CO2xe2x80x94,
or mixtures thereof with the proviso that when X does not bear a negative charge, the compound is a salt and (b) a skin compatible carrier for the said compound. Such counterion making the salt is derived from an inorganic acid such as hydrochloric, sulfuric, phosphoric and the like or organic acids such as acetic, lactic, citric and the like.
The composition can be used to moisturize the skin. Significant measurable increases in moisture can be obtained when the composition is applied to the skin. The composition can be in the form of a liquid, solid, or gelled cleansing formulation. Such liquids or gels can be in various cosmetic forms such as lotion, cream and the like. A desirable form is a liquid cleansing composition. The preferred compound is a salt of choline, for example, the chloride salt. When using a salt of choline, a physiologically compatible aliphatic organic acid need not be present in the composition in the range of about 0.05 to about 15 percent by weight of the composition, or even about 0.1 to about 10 wt % of the composition. In fact, such physiologically compatible aliphatic organic acid need not be present in the composition at all.
The moisturizing compound can be formulated into a variety of compositions, liquid, solid and gel-like for delivery of its moisturizing benefit. When formulated with a solid, the moisturizing compound can be present with large or small quantities of soap with the remainder of the surfactant being none, smaller or larger quantities of anionic surfactant such as synthetic surfactant. When formulated with a liquid or gel composition, the moisturizing compound is formulated with various amounts of water depending upon the usage of the composition as a cleansing composition, as well as various surfactants of an anionic, nonionic, cationic, amphoteric type, or mixtures thereof. The liquid or gel formulations, particularly the liquids can be formed as a cream or lotion or free flowing liquid which has cleaning abilities, moisturizing and/or conditioning abilities, or a mixture of the cleansing with the moisturizing and/or conditioning benefits. By conditioning is meant increasing the smoothness or suppleness of the skin. By moisturizing is meant the actual increasing of water content of the skin.
Other conditioning and moisturizing agents also can be present in the compositions of the invention. Typical moisturizing or conditioning materials include urea, lactic acid, pyrrolidone carboxylic acid, amino acids and salts of the acids mentioned.
Occlusive agents are further examples of substances which can be present in the composition. These are substances which form on the skin thin films of limited permeability, serving to hold water within the skin and prevent dehydration. The range of occlusive agents is considerable. They are generally hydrophobic oils and waxes. Examples of classes of such agents and individual examples of such agents are:
1. Hydrocarbon oils and waxes. Examples thereof are mineral oil, petrolatum, paraffin, ceresin, ozokenite, microcrystalline wax.
2. Silicone oils, such as dimethyl polysiloxanes, methylphenyl polysiloxanes, silicone glycol copolymers.
3. Triglyceride esters, for example, vegetable and animal fats and oils.
4. Glyceride esters and esters such as acetylated monoglycerides, and ethoxylated monoglycerides.
5. Alkyl and alkenyl esters of fatty acids having 10 to 20 carbon atoms. Examples include hexyl laurate, isohexyl laurate, isohexyl palmitate, isopropyl myristate, isopropyl palmitate, decyl oleate, isodecyl oleate, hexadecyl stearate, decyl stearate, isopropyl isostearate, diisopropyl adipate, diisohexyl adipate, dihexyl decyl adipate, diisopropyl sebacate, lauryl lactate, myristyl lactate, cetyl lactate, oleyl myristate, oleyl stearate and oleyl oleate.
6. Fatty alcohols having 10 to 20 carbon atoms. Lauryl, myristyl, cetyl, hexadecyl, stearyl, isostearyl, hydroxystearyl, oleyl, ricinoleyl, behenyl, erucyl, and 2-octyl dodecanyl alcohols are examples of satisfactory fatty alcohols.
7. Lanolin and derivatives. Lanolin, lanolin oil, lanolin wax, lanolin alcohols, lanolin fatty acids, isopropyl lanolate, ethoxylated lanolin, ethoxylated lanolin alcohols, ethoxylated cholesterol, propoxylated lanolin alcohols, acetylated lanolin, acetylated lanolin alcohols and lanolin alcohols (inoleate are illustrative emollients derived from lanolin.
8. Natural waxes, esters thereof and ethoxylated natural waxes, beeswax, spermaceti, myristyl myristate, stearyl stearate, polyoxyethylene sorbitol beeswax, carnauba wax and candelilla wax.
Especially desirable are C2-C4 alkyl esters of C12-C18 fatty acids, such as isopropyl myristate, and isopropyl palmitate and petrolatum.
Humectants can also be present in the composition and are especially C2-C6 polyols notably glycerol, sorbitol, propylene glycol and 1,3-butylene glycol. A further example of humectant is polyethylene glycols having molecular weights of from about 100 to about 1500. Humectants do not themselves form occlusive films but may cooperate with other materials to form a film having occlusive properties. It is, therefore, desirable that humectants are not the sole category of skin emollient agent present.
Examples of surfactant which can be employed in the composition include anionic, nonionic, amphoteric and cationic.
Any anionic surfactant can be employed. Examples of such anionic surfactants include soap, a long chain alkyl or alkenyl, branched or normal carboxylic acid salt such as sodium, potassium, ammonium or substituted ammonium salt, can be present in the composition. Exemplary of long chain alkyl or alkenyl are from about 8 to about 22 carbon atoms in length, specifically about 10 to about 20 carbon atoms in length, more specifically alkyl and most specifically normal, or normal with little branching. Small quantities of olefinic bond(s) may be present in the predominantly alkyl sections, particularly if the source of the xe2x80x9calkylxe2x80x9d group is obtained from a natural product such as tallow, coconut oil and the like. Anionic nonsoap surfactants can be exemplified by the alkali metal salts of organic sulfate having in their molecular structure an alkyl radical containing from about 8 to about 22 carbon atoms and a sulfonic acid or sulfuric acid ester radical (included in the term alkyl is the alkyl portion of higher acyl radicals). Preferred are the sodium, ammonium, potassium or triethanolamine alkyl sulfates, especially those obtained by sulfating the higher alcohols (C8-C18 carbon atoms), sodium coconut oil fatty acid monoglyceride sulfates and sulfonates; sodium or potassium salts of sulfuric acid esters of the reaction product of 1 mole of a higher fatty alcohol (e.g., tallow or coconut oil alcohols) and 1 to 12 moles of ethylene oxide; sodium or potassium salts of alkyl phenol ethylene oxide ether sulfate with 1 to 10 units of ethylene oxide per molecule and in which the alkyl radicals contain from 8 to 12 carbon atoms, sodium alkyl glyceryl ether sulfonates; the reaction product of fatty acids having from 10 to 22 carbon atoms esterified with isethionic acid and neutralized with sodium hydroxide; water soluble salts of condensation products of fatty acids with sarcosine; and others known in the art for example taurates, phosphate, and those listed in the Mr. Cutcheon""s Encylopedia of Surfactants.
Although not necessary other surfactants may be present in the composition. Examples of these surfactants include zwitterionic surfactants can be exemplified by those which can be broadly described as derivatives of aliphatic quaternary ammonium, phosphonium, and sulfonium compounds, in which the aliphatic radicals can be straight chain or branched and wherein one of the aliphatic substituents contains from about 8 to 18 carbon atoms and one contains an anionic water-solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. A general formula for these compounds is:
wherein R2 contains an alkyl, alkenyl, or hydroxy alkyl radical of from about 8 to about 18 carbon atoms, from 0 to about 10 ethylene oxide moieties and from 0 to 10 glyceryl moiety; Y is selected from the group consisting of nitrogen, phosphorus, and sulfur atoms; R3 is an alkyl or monohydroxyalkyl group containing 1 to about 3 carbon atoms; x is 1 when Y is a sulfur atom and 2 when Y is a nitrogen or phosphorus atom, R4 is an alkylene or hydroxyalkylene of from 0 to about 4 carbon atoms and Z is a radical selected from the group consisting of carboxylate, sulfonate, sulfate, phosphonate, and phosphate groups.
Examples include:
4-[N,N-di(2-hydroxyethyl)-N-octadecylammonio]-butane-1-carboxylate;
5-[S-3-hydroxypropyl-S-hexadecylsulfonio]-3 hydroxy-pentane-1-sulfate
3-[P,P,P-diethyl-P 3,6,9 trioxatetradecyl-phosphonio]-2-hydroxypropane-1-phosphate
3-[N,N-dipropyl-N-3 dodecoxy-2-hydroxy-propylammonio]-propane-1-phosphonate
3-(N,N-di- methyl-N-hexadecyl-ammonio) propane-1-sulfonate; 3-(N,N-dimethyl-N-hexadecylammonio)-2-hydroxypropane-1-sulfonate
4-(N,N-di(2-hydroxyethyl)-N-(2 hydroxydodecyl) ammonio]butane-1-carboxylate
3-[S-ethyl-S-(3-dodecoxy-2-hydroxy-propyl)sulfonio]-propane-1-phosphate
3-(P,P-dimethyl-P-dodecylphosphonio)-propane- 1-phosphonate; and
5-[N,N-di(3-hydroxypropyl)-N-hexadecyl-ammonio]-2-hydroxy-pentane- 1-sulfate.
Examples of amphoteric surfactants which can be used in the compositions of the present invention are those which can be broadly described as derivatives of aliphatic secondary and tertiary amines in which the aliphatic radical can be straight chain or branched and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. Examples of compounds falling within this definition are sodium 3-dodecylaminopropionate, sodium 3-dodecylaminopropane sulfonate, N-alkyltaurines, such as the one prepared by reacting dodecylamine with sodium isethionate according to the teaching of U.S. Pat. No. 2,658,072, N-higher alkyl aspartic acids, such as those produced according to the teaching of U.S. Pat. No. 2,438,091, and the products sold under the trade name xe2x80x9cMiranolxe2x80x9d and described in U.S. Pat. No. 2,528,378. Other amphoterics such as betaines are also useful in the present composition.
Examples of betaines useful herein include the high alkyl betaines such as coco dimethyl carboxymethyl betaine, lauryl dimethyl carboxy-methyl betaine, lauryl dimethyl alpha-carboxyethyl betaine, cetyl dimethyl carboxymethyl betaine, lauryl bis-(2-hydroxyethyl)carboxy methyl betaine, stearyl bis-(2-hydroxypropyl) carboxymethyl betaine, oleyl dimethyl gamma-carboxypropyl betaine, lauryl bis-(2-hydroxypropyl) alpha-carboxyethyl betaine, etc. The sulfobetaines may be represented by coco dimethyl sulfopropyl betaine, stearyl dimethyl sulfopropyl betaine, amido betaines, amidosulfobetaines, and the like.
Many cationic surfactants are known to the art. By way of example, the following may be mentioned:
stearyldimethylbenzyl ammonium chloride;
dodecyltrimethylammonium chloride;
nonylbenzylethyldimethyl ammonium nitrate;
tetradecylpyridinium bromide;
laurylpyridinium chloride;
cetylpyridinium chloride
laurylpyridinium chloride;
laurylisoquinolium bromide;
ditallow(hydrogenated)dimethyl ammonium chloride;
dilauryldimethyl ammonium chloride; and
stearalkonium chloride.
Additional cationic surfactants are disclosed in U.S. Pat. No. 4,303,543. See column 4, lines 58 and column 5, lines 1-42, incorporated herein by references. Also see CTFA Cosmetic Ingredient Dictionary, 4th Edition 1991, pages 509-514 for various long chain alkyl cationic surfactants; incorporated herein by references.
Nonionic surfactants can be broadly defined as compounds produced by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound, which may be aliphatic or alkyl aromatic in nature. Examples of preferred classes of nonionic surfactants are:
1. The polyethylene oxide condensates of alkyl phenols, e.g., the condensation products of alkyl phenols having an alkyl group containing from about 6 to 12 carbon atoms in either a straight chain or branched chain configuration, with ethylene oxide, the said ethylene oxide being present in amounts equal to 10 to 60 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds may be derived from polymerized propylene, diisobutylene, octane, or nonane, for example.
2. Those derived from the condensation of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine products which may be varied in composition depending upon the balance between the hydrophobic and hydrophilic elements which is desired. For example, compounds containing from about 40% to about 80% polyoxyethylene by weight and having a molecular weight of from about 5,000 to about 11,000 resulting from the reaction of ethylene oxide groups with a hydrophobic base constituted of the reaction product of ethylene diamine and excess propylene oxide, said base having a molecular weight of the order of 2,500 to 3,000, are satisfactory.
3. The condensation product of aliphatic alcohols having from 8 to 18 carbon atoms, in either straight chain or branched chain configuration with ethylene oxide, e.g., a coconut alcohol ethylene oxide condensate having from 10 to 30 moles of ethylene oxide per mole of coconut alcohol, the coconut alcohol fraction having from 10 to 14 carbon atoms. Other ethylene oxide condensation products are ethoxylated fatty acid esters of polyhydric alcohols (e.g., Tween 20-polyoxyethylene (20) sorbitan monolaurate).
4. Long chain tertiary amine oxides corresponding to the following general formula:
R1R2R3Nxe2x86x92O
xe2x80x83wherein R1 contains an alkyl, alkenyl or monohydroxy alkyl radical of from about 8 to about 18 carbon atoms, from 0 to about 10 ethylene oxide moieties, and from 0 to 1 glyceryl moiety, and, R2 and R3 contain from 1 to about 3 carbon atoms and from 0 to about 1 hydroxy group, e.g., methyl, ethyl, propyl, hydroxy ethyl, or hydroxy propyl radicals. The arrow in the formula is a conventional representation of a semipolar bond. Examples of amine oxides suitable for use in this invention include dimethyldodecylamine oxide, oleyl-di(2-hydroxyethyl) amine oxide, dimethyloctylamine oxide, dimethyldecylamine oxide, dimethyltetradecylamine oxide, 3,6,9 trioxaheptadecyldiethylamine oxide, di(2-hydroxyethyl)-tetradecylamine oxide, 2-dodecoxyethyl-dimethylamine oxide, 3-dodecoxy-2-hydroxypropyldi(3-hydroxy-propyl)amine oxide, dimethylhexadecylamine oxide.
5. Long chain tertiary phosphine oxides corresponding to the following general formula:
RRxe2x80x2Rxe2x80x3Pxe2x86x92O
xe2x80x83wherein R contains an alkyl, alkenyl or monohydroxyalkyl radical ranging from 8 to 20 carbon atoms in chain length, from 0 to about 10 ethylene oxide moieties and from 0 to 1 glyceryl moiety and Rxe2x80x2 and Rxe2x80x3 are each alkyl or monohydroxyalkyl groups containing from 1 to 3 carbon atoms. The arrow in the formula is a conventional representation of a semipolar bond.
Examples of suitable phosphine oxides are:
dodecyldimethylphosphine oxide, tetradecylmethylethyl-phosphine oxide,
3,6,9-trioxaoctadecyldimethyl-phosphine oxide, cetyldimethylphosphine oxide,
3-dodecoxy-2-hydroxypropyldi(2-hydroxyethyl) phosphine oxide stearyldimethyl-phosphine oxide,
cetylethyl propylphosphine oxide,
oleyldiethylphosphine oxide,
dodecyldiethylphosphine oxide,
tetradecyldiethylphosphine oxide,
dodecyldipropylphosphine oxide,
dodecyldi(hydroxymethyl)phosphine oxide,
dodecyldi(2-hydroxy-ethyl)phosphine oxide,
tetradecyl-methyl-2 -droxypropylphosphine oxide,
oleyldimethylphosphine oxide, and
2-hydroxydodecyldimethylphosphine oxide.
6. Long chain dialkyl sulfoxides containing one short chain alkyl or hydroxy alkyl radical of 1 to about 3 carbon atoms (usually methyl) and one long hydrophobic chain which contain alkyl, alkenyl, hydroxy alkyl, or keto alkyl radicals containing from about 8 to about 20 carbon atoms, from 0 to about 10 ethylene oxide moieties and from 0 to 1 glyceryl moiety. Examples include: octadecyl methyl sulfoxide, 2-ketotridecyl methyl sulfoxide, 3,6,9-trioxaoctadecyl 2-hydroxyethyl sulfoxide, dodecyl methyl sulfoxide, oleyl 3-hydroxypropyl sulfoxide, tetradecyl methyl sulfoxide, 3 methoxytridecylmethyl sulfoxide, 3-hydroxytridecyl methyl sulfoxide, 3-hydroxy-4-dodecoxybutyl methyl sulfoxide.
7. Alkylated polyglycosides include wherein the alkyl group is from about 8 to 20 carbon atoms, preferably about 10 to about 18 carbon atoms and the degree of polymerization of the glycoside is from about 1 to about 3, preferably about 1.3 to about 2.0.
The quantities of the moisturizing compound or mixtures thereof of the invention which can be employed is any moisturizing effective amount. Generally there is at least about 0.1 wt % of the composition, desirably at least about 0.5 wt % of the composition, and more desirably at least about 1 wt % of the composition as the compound or mixtures thereof of the invention. Generally, no more than about 20 wt % of the composition is the moisturizing agent or mixtures thereof of the invention, desirably no more than about 10 to 15 wt % of the composition. The desirability of the quantity is generally the balance between the desirable qualities of the compound or mixtures versus any undesirable effects such material(s) might have on the overall composition effects.
Surfactants can be present in a composition wherein cleansing is not a goal but emulsification of any conditioning agent in the composition is desirable. Generally a minimum of about 0.5 wt % of surfactants can be employed for emulsification purposes. Therefore, an emulsifying quantity of surfactant can be employed. Surfactants can also be employed in a composition wherein cleansing is a goal. A cleansing effective amount should be employed. For cleaning purposes, at least about 1 wt %, desirably at least about 2 or 3 wt % of surfactant is desirable.

Skin moisturizing composition comprising a choline salt

Abstract: (a) a moisturizing effective amount of a compound of the structure:

Abstract: CH2OH, CH OH CH2 CO2xe2x80x94,

Abstract: or mixtures thereof wherein when X does not bear a negative charge, the said compound is a salt; and

Abstract: (b) a skin compatible carrier.


Edible films incorporating carrageenan in conjunction with Konjac and/or Gellan gums have been prepared as substitutes for edible collagen film currently used in meat processing. Compositions according to the present invention overcome the inherent thermoreversibility of carrageenan gel and do not disintegrate from exposure to hot or boiling water. The film can readily be processed to form casing, bags or other packaging useful in the food industry.

For a number of years, edible films have been used to replace membranes and casings made of animal viscera, in the production of smoked meat products such as ham and sausages. Currently available edible films include collagen films, modified cellulose films and carrageenan-based films.
Collagen films are composed of edible collagen, plasticized with glyerol or other polyols. They are manufactured by extrusion onto a belt followed by drying to remove the moisture. The collagen slurry is applied to the belt cold, and requires high-temperature drying to remove all the excess moisture and bring the film to a final moisture content of approximately 10%. Apart from the difficulty in processing films of this kind, these materials can bring about allergic reactions in certain consumers. Too, being derived from the coum layer of beef or pork, collagen may be an unacceptable casing or film material for religious and dietary reasons.
Modified cellulose films are for the most part composed of modified hydroxypropyl methylcellulose. To date, almost all films of this kind which have been produced are cold water-soluble films which begin to disintegrate on contact with water. For this reason, they have not been used in meat processing.
Carrageenan is a polyanionic polysaccharide derived from red algae. The material is an excellent film-former and has been used in the formulation of edible food packaging films (U.S. Pat. No. 4,851,394) and heat-sealable edible films (U.S. Pat. No. 5,089,307xe2x80x94Ninomiya et al.). Films composed primarily of carrageenan additionally exhibit excellent strength, are not soluble in cold water and bind well to meat
However, because carrageenan forms a thermoreversible gel, films composed of a predominant carrageenan proportion tend to disintegrate in hot water, i.e. above 70xc2x0 C. The hot carrageenan aqueous solution then re-gels upon contact with cooler water, less than 50xc2x0 C.
It was one of our objectives to develop carrageenan-based films which can effectively and economically replace edible collagen films currently utilized in ham and sausage production, while providing high yields and high-quality product.
Collagen film is typically wrapped around hams during production, for ease in netting removal after the ham has been cooked. Collagen films appear to the consumer to be part of the ham after cooking and, indeed, are usually not taken note of by the average consumer. Many styles of meats are processed using collagen films, including various ham, chicken and turkey products.
It is an object of the present invention to provide polysaccharide films which would function well by satisfying all of the following key attributes:
composed of food ingredients which meet Food Chemical Codex Specifications and are approved for usage, i.e. GRAS rated in the United States (generally regarded as safe).
a film that would maintain its composition during the cooking cycle, until the ham forms its own natural protein skin.
after cooking, film adheres to the finished product, in that it does not fully disintegrate after a prolonged exposure to hot water or steam.
film is tender to eat following processing of the meat product.
film binds to the meat surface during and subsequent to processing.
film is permeable to flavouring smoke.
film imparts an appealing shine and colour to the cooked product.
We have found that excellent properties for edible films can be achieved by including, along with the carrageenan, suitable non-thermoreversible gel-forming polymers, preferably Konjac and Gellan gums. Konjac is extracted from the konjac tuber. This polysaccharide hydrates immediately and can form either thermoreversible or non-thermoreversible gels, depending on the conditions under which the gel is formed. Gellan gum is a polysaccharide gum produced from bacterial fermentation. It is a strong gel former and produces gels that are non-thermoreversible in the presence of Ca+2 and other multivalent anions. Both Konjac and Gellan gums are edible and GRAS rated. We observed that Konjac tends to form gels having a higher degree of elasticity than Gellan, which forms gels having a more brittle texture.
According to present invention, edible films and casing materials comprise a polymer base of carrageenan/Konjac/Gellan, and also a suitable starch, alginate or other polysaccharide, depending on the specific attributes required.
Starch functions to reduce water absorption of the film and it is preferred that a high-amylose starch be used, as high-amylose starch is inherently a better film-former than other starches.
xe2x80x9cAlginatexe2x80x9d herein refers to the alginates which are commonly used in the food industry, namely polypropylene glycol alginate, sodium alginate or calcium alginate. Alginate in compositions according to the present invention tend to produce strong films exhibiting good adhesion.
Specific methods and formulations are described in more detail below, but generally we have found the following compositions to provide useful edible films:
The synergistic effects of the main polymers, Gellan Konjac and carrageenan, function to produce a film of high tensile strength, hot and cold water resistance and gum substrate adherence.
The use of a protein source is desirable to provide the film with both improved adhesion and shine functionality. The presence of some (at least about 5%) of alginatge or starch component is necessary to give sufficient film casing adhesion.
Other polysaccharides, as discussed below, may be added to impart specific desired properties to the film. Glyerol was added for its elasticizing effects. Optionally, calcium chloride or potassium carbonate may be utilized to improve the film strength and hot water resistance.
From other formulations tested it is possible to significantly alter the relative amounts of each gel-forming polymer in the film to produce films exhibiting some varying degree of hot water solubility.
Polymer solutions were prepared for film casting as follows: glyerol or other plasticizers were added to the requisite amount of hot water. While maintaining the solution at an elevated temperature (80-90xc2x0 C.), then the dry ingredients were added and the solution vigorously mixed to homogeneity. The polymer solution was then continuously mixed under slow agitation for 1-2 hours to remove trapped air bubbles.
Once the polymer solution appeared to be smooth and free of lumps, it was cast into film, using either a casting box or with a standard draw down bar. Care must be taken to ensure that the hot solution is cast in a uniform thin layer. In all of the experimental examples given below, film was formed by drawing the solution down onto a hot (90xc2x0 C.) stainless steel belt with a Gardener dye. The films were either air dried overnight at room temperature, or dried over a hot water bath and then removed for testing.
Films produced this way would initially be tested for thickness using a micrometer (Gauge) and tensile/tear strength.
The methods for measuring tear strength and elongation are those specified in ASTMD638. Normally 5 specimens are tested from each of 5 samples with the following conditions
20 lbf load cell
Crosshead speed: 2 in./minute
Die xe2x80x9cCxe2x80x9d cut specimens
Films that met these requirements would then be tested for hot water solubility by placing strips of the film in boiling water and then allowing the water to cool with the film sample in it. After cooling, the water would then be drained off and non-solubilized material would be placed with the drain dish in the drying overn. If the film was reconstituted after drying then the film was deemed to have maintained its structure during exposure to the hot water. If the film was not resistant to the water then it would become soluble and could be poured off. (Hence no film left after drying)
After a particular sample had been characterized as above, it would be subjected to the same process conditions under which commercial meats are produced. In particular the film would be wrapped around a particular meat substrate (turkey, ham, chicken) and then the wrapped meat sample dried in a convection oven until a protein skin could be seen forming on the sample. After this the sample was transferred into a steam cooker for the completion of cooking. The internal temperature of the meat sample would have to reach 70-80xc2x0 C. After the completion of cooking, the sample was allowed to cool and the final product examined and results recorded. Samples were then packed away under vacuum for shelf-life testing.
Films according to the invention which we tested on meat film wrap were also produced using the following polysaccharides, supplementary to starch and/or alginate, with Gellan and/or Konjac: agar, modified starches, guar gum, cellulose gum, modified cellulose gum, gum arabic, pullian and xanthate.
In some of the formulations, the following proteins were included: gelatin, soya protein concentrate, soya protein isolate, whey protein concentrate, albumin, miscellaneous vegetable proteins, collagen and collagen hydrolysates.
The following general observations arose from our experiments:
(i) Either Gellan and/or Konjac is required for synergistic reaction with the carrageenan and other gums or polysaccharide to provide the desired hot water resistance. The proportion of Gellan and/or Konjac is that amount necessary to modify carrageenan sufficiently to ensure that the film will not disintegrate upon exposure to hot water. Films could be made out of Konjac or Gellan alone, but these would be far less economical than the combination with other polysaccharide and in any event would have inferior physical properties, e.g. poor film strength, susceptibility to hydration, etc.
(ii) The presence of starch or alginate is essential in these compositions to impart proper adhesion at the final film in its intended use as food film and casing.
(iii) Added protein is highly advantageous, to ensure proper adherence of the film to the meat after completion of cooking and for the aforementioned aesthetic purpose of mimicking the glossy appearance imparted by collagen.
The film compositions may also be modified by the addition of compounds for specific purposes, such as
1. anti-microbial;
2. release agents;
3. colourants (i.e. caramels, oleoresins and other synthetic or natural colourantsxe2x80x94iron oxide);
4. flavors and spices.
With particular application to meat processing, black films can be produced using caramel, so that processors need no longer dip the meat products in a liquid caramel to obtain that colour.


An internal spa filter for a spa, having a filter body with an inlet opening at its one end and a discharge orifice at its opposite end, the sides of such body are formed with auxiliary spa water inlet openings. The filter also includes a filter bag having a sheath encompassing the exterior of the filter body and a pocket extending inwardly from the front end of the sheath into the filter body from the main spa water inlet opening. Operation of the spa water circulation system draws spa water into the main spa water inlet opening through the filter bag pocket into the filter body while concurrently spa water is drawn transversely through the filter bag sheath and auxiliary spa water openings into the filter body, all of such spa water flows rearwardly out of the filter body through the filter body discharge orifice.

1. Field of the Invention
The present invention relates to filters for liquids. More particularly, the present invention is directed to an internal filter for use in the water circulation systems of conventional pools or spas.
2. Description of the Prior Art
Filters of various configurations are known in the art for use in swimming pools, spas, and the like in order to remove solid particles and debris from the circulated water. Such filters are typically mounted in-line within the pool or spa circulation system and are configured with a liquid-permeable filter media such that when the circulation system is in operation, the water can be pulled through the filter and pumped back into the pool or spa, leaving the captured debris on the filter for subsequent removal.
The conventional cartridge filter as is known and used in the art is generally comprised of a cylindrical filter element having one or more layers or sheets of a porous material configured with a pore size to allow the passage of water while trapping and removing the solid particles from the water that are unable to pass through the pores. As the filter traps more and more solid particles, the pores in the filter media become clogged, inhibiting the flow of water through the pool or spa""s circulation system and thereby decreasing performance and possibly even damaging the circulation pump. In an attempt to address these concerns, the cartridge filters known in the art typically employ relatively large sheets of the porous filter material that are pleated so as to provide an increased filter surface area, thus increasing the life and performance of the filter, while not increasing the filter""s overall size. The filter material is maintained in its cylindrical, pleated configuration by being mounted on a rigid cylindrical core and capped on each end by an annular end cap.
Though the conventional cartridge filter is in wide use, there are still several shortcomings with this filter type that have not yet been overcome. First, the flow rate through the cartridge filter is limited by the material and configuration of the pleats and the apertures in the rigid cylindrical core. Such flow rate is typically on the order of 100 gpm when the filter is new. Second, despite the overall increased surface area of the filter material achieved by the pleats, only so much of this surface area is truly usable, as the folds of the pleat are tight and are butted up against the cylindrical core. Moreover, as particles and debris become lodged between the pleats, the useful filter surface area that is lost is effectively doubled because the particles and debris clog pores on both adjacent surfaces of the pleat. Thus, cartridge filters become clogged and experience decreased flow rates relatively quickly. A third shortcoming of the cartridge filters known and used in the art is that they cannot be readily cleaned after becoming clogged. In the interest of increasing the total filter surface area, the pleats of the typical cartridge filter are numerous and densely configured about the filter""s circumference. Thus, in order to remove the debris trapped deep within the pleat folds, high pressure reverse flow or meticulous debris removal using a vacuum or manual technique between each pleat is necessary. It is further recommended that the cartridge be soaked overnight in a cartridge cleaning solution and then be thoroughly cleaned a second time before being returned to use. Because of these inconveniences, some pool and spa owners simply use their cartridge filters until they become clogged and discard them, often prematurely, rather than bothering to clean them out. Moreover, because cartridge filters trap debris on the outside of the filter only, when the filter is removed from the pool or spa for cleaning or disposal, it is possible that the debris that is loose and easily removed will fall off the filter into the clean side of the circulation system rather than being permanently removed.
For these reasons, other pool and spa filters have been proposed in the art. Diatomaceous earth (xe2x80x9cDExe2x80x9d) filters house internal, parallel grids made of extremely fine mesh that is coated with DE, which is crushed, petrified bone that acts as an adhesive and traps particles and debris from the water as it is filtered through the layers of DE grids. These DE filters are relatively more expensive than comparable cartridge filters and may be subject to municipal or environmental authority regulations pertaining to cleaning and disposal. Similarly, sand filters have also been proposed that essentially use a sand and gravel filter medium that mixes with the circulated water as it passes through the filter to pull out dirt and debris. However, the debris is not permanently captured by the sand filter medium and can eventually work its way through the filter and back into the pool or spa circulation system. It has been proposed that an additional solution be added to the sand to coagulate the particles and debris being filtered into larger clumps that can be more easily trapped by the sand filter medium. As a further maintenance step with sand filters, periodically, the sand itself is depleted from the filter and more sand of a specific type must be added. Sand filters, like the DE filters, are more costly than cartridge filters.
Bag-type filters for separation of unwanted solids from liquid process flows have also been employed in various industrial filtration applications in the interest of increasing flow rate and efficiency. To this end, filter assemblies having bag filters supported on rigid structures or stiffening frames and having elaborate sealing arrangements between the filter and the surrounding housing have been proposed. For example, U.S. Pat. No. 4,769,052 to Kowalski is directed to a flexible fabric filter bag apparatus having multiple support surfaces. A double-walled, porous cylinder cooperates with a stretching frame to suspend and support the filter bag within a rigid cylindrical outer housing. An annular flange is provided in the housing""s inner wall and is configured to sealingly engage a metal ring within the bag""s open end when the bag, the double-walled cylinder, and the stretching frame are positioned inside the outer housing. A cover is installed over the open end of the outer housing to seal the filter and to force the stretching frame downwardly to draw the filter bag taut against the surfaces of the double-walled support cylinder.
U.S. Pat. No. 5,910,247 to Outterside is directed to a similar filter bag system. Like the Kowalski filter apparatus, Outterside discloses essentially a double-walled filter support cylinder, consisting of an outer basket and an inner tubular member, a housing having a lid for sealing the filter, and a filter bag having a ring in its open end to sealingly engage a flange on the basket. Outterside further discloses specific dimensions for the filter bag which purportedly maximize the surface area without restricting the process flow rate. Moreover, the Outterside system""s supporting structures are configured to prevent collapse of the filter bag when the process flow is reversed to backwash and clean the filter without removing it. Hence, it is essential that the filter bag fit snugly and securely over the outer basket and inner tubular member. To this end, Outterside discloses that the filter body is smaller in diameter than the outside diameter of the tubular support member so that the filter must be stretched to fit over the tubular body and is retained thereon through a frictional fit.
Therefore, the bag filters known and used in the prior art essentially entail a multi-walled support structure that may further include additional stretching or stiffening frames, a filter bag that is secured on the support structure and shaped by the alternative frames, and a filter housing, or vessel, that contains the filter bag assembly and provides for a positive seal between the xe2x80x9cdirtyxe2x80x9d and xe2x80x9ccleanxe2x80x9d side of the filter along a ring integral to the bag""s open end. Based on the configuration and number of components in these prior art industrial bag-type filters, it follows that such filters are not well-suited for use in spas because of their complex design and inherent relatively high cost. Furthermore, the housing, which plays a critical role in the function and performance of the prior art bag-type filters, is particularly ill-suited for use in a spa""s circulation system because the conventional spa""s filter-receiving cavity cannot accommodate the housing, and the housing itself, having only one small inlet strategically positioned above the location where the filter is sealed within the housing, would likely perform poorly under the changing water levels and other conditions of a pool or spa during use.
Thus, there exists a need for an inexpensive, convenient, and functionally efficient filter for use in spas and the like that is both easily reusable and disposable.
The present invention is directed to an internal spa filter including a filter body and a complementary filter bag having a sheath which encompasses the exterior of the filter body and an internal pocket which extends into the filter body. The filter body is configured to be installed within a spa""s water circulation system in order to filter particles and debris out of the water. As the spa water is circulated, through the filter body a vortex effect is created within the filter bag pocket trapping debris therein for later removal without the risk of the debris falling off the filter and back into the spa water. The configuration and materials of the spa filter of the present invention, as compared to the prior art filters, provide for much higher flow rates through the filter, further enhancing both the performance and life of the pump of the spa circulation system. Moreover, the spa filter of the present invention is relatively inexpensive to manufacture, whereby, after prolonged use, the filter bag itself may be either readily cleaned and reused or alternatively simply discarded.
The filter body of the spa filter of the present invention is defined by a cylinder having a spa water opening at its inlet end and a spa water discharge orifice at its opposite end. Throughout the filter body""s cylindrical wall is formed, a pattern of auxiliary spa water inlet openings. The inlet and auxiliary openings permit the passage of the circulated spa water from the outside of the filter body to the inside thereof. The sheath of the filter bag is joined to the pocket thereof along a circumferential inseam. Accordingly, when the bag is placed about the filter body, the closed end of the pocket is inserted within the filter body""s open end while the sheath encompasses the outside surface of the filter body""s cylindrical wall, with the inseam of the filter bag positioned substantially along the inlet edge of the cylindrical wall""s inlet end to maintain the position of the filter bag on the supporting filter body. The pocket extends towards the discharge end of the filter body.
One embodiment of the filter body utilizes a cylinder, the sides of which are formed with a pattern of round through-hole openings preferably having a nominal diameter of 0.60xe2x80x3. For a cylinder having an outside diameter of approximately 5xc2xd and a length of approximately 8xe2x80x3, sixteen such holes are radially-spaced apart in each of six parallel, circumferential rows in the wall to yield a total of ninety-six through holes generally spaced uniformly throughout the wall. In an alternative filter body embodiment, a mesh-type pattern is formed in the cylinder sidewall having a pattern of small, square apertures throughout the wall arranged in spaced-apart relationship about parallel circumferential rows substantially throughout the wall. Because the square apertures are relatively smaller than the through-hole apertures of the first embodiment, for the same overall dimensions of the wall, the number of square apertures and the number of rows are significantly increased, yielding a total of more than two-thousand square apertures. A third embodiment of the filter body of the present invention has lengthwise axially extending slots formed about its circumference.
In each embodiment of the filter body, the body includes an open inlet end about which the filter bag sheath is draped and an opposite rear closed discharge end formed by a rear wall integral with the rear end of the filter body and generally normal to the axis of the filter body. A central circular discharge orifice is provided in the wall for discharge of the flow of the spa water entering the filter body through the filter bag. A length of tubing extends from the discharge orifice normal to the rear wall and projecting axially away from the filter body. The tubing is configured with external threads for threadably engaging piping of the spa""s circulation system. Preferably, the filter body will be positioned vertically within a filer-receiving bag of the spa with the inlet end of the cylinder disposed above the discharge end thereof so that water from the tub of the spa is drawn downwardly through the filter body to the suction end of the spa""s pump. The filter body may be constructed of a thermoplastic material such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), or acrylonitrile butadiene styrene (ABS). These materials are readily available, are relatively inexpensive, and are easily processed using injection molding and finishing techniques known in the art.
The filter bag of the present invention includes a support ring at the juncture of the sheath and pocket along a circumferential inseam formed by looping the upper end of the pocket over the upper end of the sheath to form a loop or circumferential cavity. The support ring preferably has a nominal diameter substantially equivalent to the nominal diameter of the filter body so as to be positioned adjacent the upper end of the filter body when the filter bag is placed on the filter body, thereby maintaining the filter bag in position and keeping the pocket open during use. To this end, the support ring is to be constructed of any suitable rigid or semi-rigid material such as a thermoplastic material or stainless steel. To maintain the position of the support ring within the circumferential cavity and to secure the inseam, stitching, welding, stapling or other fabric attachment means known in the art are employed.
A removal handle spans the open upper end of the filter bag pocket and is attached at two opposite locations. The handle may be stitched, welded, or otherwise joined to the filter bag using any attaching means known in the art, but is preferably attached within the inseam itself. The length of the handle is sufficient to loosely span the pocket opening, so that the handle may droop within the pocket when not in use and may be pulled up for convenient access when the handle is to be grasped to remove the filter bag from the filter body.
The filter bag of the present invention may be constructed of a durable, porous, fibrous material known in the art for use in various filtration applications. Though many types of fabrics may be used in fluid filtration to effectively remove debris and particulate matter while allowing the fluid itself to pass through the filter media, in a preferred embodiment, the material selected will have a porosity rating of 40 to 50 microns and have a weight on the order of 12 oz/yd2. Examples of suitable materials include polypropylene (PP), polyethylene (PE), polyester felt, or fiberglass. The handle may be made of the same material as the sheath and the pocket or may be made of a conventional cotton and polyester textile material.
In operation, after the sheath of the filter bag has been removably positioned in covering relationship over the filter body with the bag pocket extending into the filter body, the internal spa filter of the present invention is ready for use and is installed within the filter-receiving bay of a conventional spa with the filter in direct communication with the spa""s circulation system on the suction side of the pump. Once the spa tub is filled with water and the circulation system is operated, the water is drawn through the filter by the pump. Because the inlet opening of the filter bag, approximately 5xc2xd diameter, is relatively larger than the discharge orifice at the closed end of the filter body, which is typically on the order of 1xc2xd, this difference in area will naturally create a vortex tending to draw the water down through the filter pocket, pulling larger debris into the pocket and trapping it there for later removal. The vortex action and the resulting strong suction of water through the filter also creates a vacuum pressure on the inside of the filter that serves to pull the filter bag""s sheath tightly against the exterior of the filter body, thus effectively creating a tight fit between the sheath and the filter body which causes all water being pulled through the filter to pass through the filter bag.
The porosity of the filter bag material, the configuration of the open pocket, and the vortex effect cooperate to provide for higher flow rates through the filter (on the order of about 150 gallons per minute) as compared to conventional prior art spa filters. This increased flow rate translates to enhanced performance of the spa in terms of the relaxation and therapeutic benefits to the user and the life of the circulation pump.
When the filter bag of the present invention has become sufficiently dirty that it should be cleaned or replaced, the spa""s circulation system is shut down and the filter bag is simply lifted out of the filter body by grasping the handle. The debris trapped by the filter during use will remain within the inside pocket, thereby not contaminating the spa water as the filter bag is removed from the filter-receiving bay. If the filter bag is removed from the spa to be cleaned for reuse, the bag is dumped or rinsed out to remove all debris that has been trapped or alternatively may be washed or laundered in a conventional washing machine and dryer to more thoroughly clean and sanitize the bag. If it is preferred that the filter bag be replaced rather than being cleaned, the used filter bag may be simply discarded and a new bag put into the filter body. Because the materials and construction methods employed in producing the filter of the present invention are relatively inexpensive, disposing of the filter bag is both a convenient and economical it cleaning the bag.
Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the features of the invention.


For sensing a control point on a capacitive-type panel, first and second voltage signals are respectively received through two sets of receiving lines selected from N receiving lines in response to first and second charge/discharge signals transmitted through two sets of transmitting lines selected from M transmitting lines, respectively, during a first time period. Third and fourth voltage signals are received through two sets of receiving lines selected from the N receiving lines in response to third and fourth charge/discharge signals respectively transmitted through the two sets of transmitting lines, respectively, during a second time period. A characteristic value is generated according to the first, second, third and fourth voltage signals. Repeat the steps to generate characteristic values for neighboring regions defined by different combinations of transmitting lines and receiving lines. Position information of control point(s) on the capacitive-type panel is estimated accordingly.

According to different working principles, common touch panels can be classified into resistive-type touch panels and capacitive-type touch panels. When a user touches or approaches the surface of the capacitive-type touch panel with his finger or a conductive object, the capacitance of the capacitive-type touch panel changes accordingly. A touch position can be located by sensing and calculating the capacitance change. A conventional two-dimensional capacitive-sensing touch panel is mainly constituted of two sets of sensing pads respectively arranged horizontally and vertically, and the two sets of sensing pads are isolated at their intersected parts with insulating material so that capacitors are formed. A two-dimensional capacitive-sensing touch panel is a mainstream among current capacitive-sensing touch panels because it can detect multiple touch points at the same time so as to meet the demand on multipoint touch sensing in the market.

Method and device for sensing control point on capacitive-type panel


Carbomer or cross-polyacrylate polymers which are conventionally provided in a powdered form are converted to a granulated, pelletized or tablet form for subsequent use, in combination with a liquid medium, to form a gel from which products such as liquid detergents, cosmetics and toiletries can be produced. Conversion of the polymer into a granular, pelletized or tablet form has been demonstrated to improve handling of the dry polymer, thereby mitigating against many of the problems incurred with the use of conventional powders, as well as to improve the rate of blending of the polymer with a liquid medium. In some embodiments, the polymer is blended with an electrolyte which may be a salt, acid or acid salt having a pK which is at least 1 unit, and preferably 2 units, greater than the pK of the polymer.

The present invention relates to carboxylic acid polymer compositions and particularly relates to concentrates of acrylic acid polymers and their use to prepare gels of diluted and neutralized polymer.
The polymers to which the invention relates include cross-linked polymers of acrylic acids which are widely used as thickeners, stabilizers and emulsifiers in many industries. Said cross-linked polyacrylic acids are produced and sold under a number of trade names for example Carbopol (B F Goodrich), Acrisint (Sigma), Pemulen (B F Goodrich), Junlon (Nihon Kogakyu) etc. They are however most often referred to by either of the generic terms carbomer and cross-polyacrylate, (developed by the Cosmetics, Toiletries or Fragrances Association). The polymer products are referred to by these names in this application.
Said products so described are supplied in the form of very fine powders with poor flow properties, and handling of these products is not easy. However, it has always been considered that the products must be in the form of very fine powder if complete wetting and reasonably rapid hydration of each particle is to take place when the products are added to a liquid medium, such as water, to form a gel from which products such as liquid detergents, cosmetics, toiletries or pharmaceutical products can be made. A consequence of the products being in the form of a very fine powder is that they have a pronounced tendency to dust and fly about the work place even when care is taken to minimise this.
It is conventionally regarded therefore that, despite the handling difficulties, the products must be supplied in the form of fine powders since, when they are to be converted to a gel, and in the initial stage of hydration for this conversion i.e., wetting of the powders, the formation of a very stiff gel on the outside of the powder particles occurs which delays and restricts the entry of further water to hydrate the remainder of the particle. The stiff gel on the outside of the particle therefore tends to prevent further water ingress into the particle, thereby retarding the formation of a smooth gel. In addition, agglomerates of the powder particles form lumps which increases the problem of wetting out and dispersion.
Furthermore, when disturbed, the dry powder tends to develop strong electrostatic charges which impairs further the ability of the powder to flow in the required direction and, in the extreme, causes small agglomerates to fly about which results in loss of material. This makes the automatic measuring out of the carbomers virtually impossible.
As a result of these problems, manufacturers of the products always advise that the said product be carefully sifted into the water in an attempt to break up the dry agglomerates which tend to form during storage. Furthermore, these carbomers, when fully swollen and hydrated, have the property of suspending insoluble gases, liquids and solids. This property, although very desirable in most instances, can make the removal of air bubbles from the mixture very difficult, if not impossible, within a reasonable period of time.
In an attempt to overcome this problem it has been proposed to prepare concentrated dispersions of resins in water. However, due to the high viscosity of said resins, they are extremely difficult or impossible to handle. A further initiative, as described in co-pending application No 9114095.4 provides, by incorporating small proportions of salts of multi-valent cations in these dispersions either by dry blending the polymer and salt together before adding them to the water, or by mixing the salt, powdered carbomer, and water in any order, a concentrate which has been found to be extremely effective and to have gained acceptance as a workable alternative.
The provision of said multi-valent cations in the blend has been found to be acceptable but further research has shown that the important factor of handling difficulties of the powdered carbomer in a dry state is not properly addressed. The addition of additional matter to the carbomer, although having an important effect on the characteristics of the carbomer, does not solve many of the other inherent handling problems of the carbomer, and also meets resistance from users reluctant to change to a product which requires new certification and approval. For example, the form in which the carbomer is provided is important in allowing improvements both in the mixing of the carbomer in a liquid medium to form the gel and also in improving the storage characteristics of the carbomer.
The aim of the present invention therefore is to provide an improvement in the form in which a polymer is provided such that the ease of mixing or blending of the polymer in a liquid medium to form a gel is improved in relation to existing powdered polymers and the polymer in its improved form is non-dusting, non-static and has improved flow-characteristics.
The present invention provides for the conversion of a powdered polymer wherein said polymer is converted to a granular, pelletised or tablet form.
Typically said polymer will be a powdered carbomer or cross polyacrylate and will, in a first embodiment, be comprised wholly of carbomer, or cross-polyacrylate.
The carbomer in its converted form will be capable of rapid dispersion when added to a liquid medium to form a gel substance.
In a second embodiment, the polymer will comprise a carbomer or cross-polyacrylate with which is blended an electrolyte to form a composition which is subsequently converted to a granular, pelletised, or tablet form.
Typically said electrolyte will have any of the following characteristics, namely it is;
readily soluble in liquid,
an acid or salt or acid salt of mono-or poly-valent cations or combinations thereof,
a salt, acid or acid salt, whose pK value is at least 0.5 units and preferably 1.0 unit, less than the pK value of the carbomer itself which is typically 4.3,
preferably solid and non-volatile at normal temperatures,
preferably non-toxic,
stable under normal storage conditions and preferably does not discolour, polymerise or change in any other way.
Typically, said electrolyte will also be non-hygroscopic.
When said electrolyte is an acid, or an acid salt, the pK value of the acid, a measure of its acidity, will, be at least equal to, and preferably 1.0 unit less than the pK value of the carbomer.
Preferably, the pK value of the acid will be 2.0 units less than the pK value of the carbomer, which typically has a pK value of 4.3.
In a further aspect of the invention, the electrolyte used in a blended form with the carbomer, will be an acid salt of mono-valent or multivalent cations.
Typically said blend will be easily granulated or pelletised and will be supplied in that form. To form said pellets, tablets, or granules into the required gel will require the conventional addition and mixing with a liquid medium followed by neutralisation of the mixture. Typically said liquid medium will be water but may also be any of an organic solvent such as ethanol, propylene glycol or a blend of a polar hydroxylic solvent and a non-swelling solvent.
Preferably, the polymer will be provided in a granular form. Typically to form granular products, either wet or dry granulation methods can be employed. Dry granulation involves the use of high pressure to force the particles into contact with each other and can be carried out either in moulds by means of a ram or by forcing the powder through a screen with rollers. Subsequently the material may be reduced in size and put through screens to enable a selected size range to be obtained. Wet granulation typically involves treatment with a small proportion of water to assist binding of the particles which then occurs without the need for high pressures. Other solvents can be used, but in this instance would be considered undesirable. Drying of the granular material may also be carried out as part of the process.
Conventionally it is generally held that for materials of the type of this invention, small particle size is essential if the rate of hydration of the said materials is to be acceptably short, hence the provision of the carbomer in powder form. This has to date, prevented the use of larger particle sizes as the rate of hydration has hitherto been deemed to too slow to be economically or practically possible. The provision of carbomerin granular, tablet or pellet form is in effect contrary to the conventional wisdom as it increases the size of the carbomer parts to be mixed, but unexpectedly achieves significant improvements.
The improvement of the mixing of the granules with the liquid medium is possibly due to the reduction of air held in the mixture allowing the quicker addition of the granules and dispersion of same.
A further, decreased degree of swelling of the composition is shown, by this invention, by optionally adding small proportions of electrolyte when the polymer is in its acid form. It is shown that only a small fraction of the amount of electrolyte required to reduce viscosity of the neutralized form of the polymers is needed to achieve the same effect in the acid form. The invention therefore provides a means of adding said electrolytes to the said polymer when the polymer is in the acidic form prior to neutralization. The fraction of the electrolyte required is so small that a reduction of viscosity of the neutralized form is less than the experimental error in measuring same and hence can be disregarded.
It has been found that the main advantages are in the handling of the polymer and at the same time improving the mixing characteristic of the polymer during hydration.
The original carbomer or cross-polyacrylate which is supplied in a powder form is necessarily of low bulk density, generally between 200 and 250 kg per cubic meter wherein the granulated product of the invention has a notably greater bulk density up to 600 kg per cubic meter hence providing considerable saving in terms of a reduced cost of packaging and storage.
A main advantage of the granulate or pellets of the invention is that by granulating or pelletising the mixture then the drawbacks of the original powders previously discussed are overcome in that the granules, pellets or tablets of the invention are non-dusting and do not develop static charges. A further advantage is that the granules flow very readily and disperse, even when rapidly added to stirred water without the disadvantage of clumping occuring. Furthermore, when required, the viscosity of the acidic gel can be reduced with the addition of the electrolytes into the carbomer and subsequently granulating the composition and hence the requirement to remove any unhydrated material by a stirring process is greatly reduced. Providing the said material in the form of granules or pellets, either with or without electrolyte additives, allows the materials to be used with automatic weighing systems hence improving the efficiency of handling of the material in comparison to those products which are currently available.
Examples comparing the effect of granulating carbomers in relation to the conventional powder are now discussed.
Carbopol 980 (BF Goodrich and Co Product) was compressed in a standard tablet press to give tablets with a diameter of 2.9 cm width and 0.8 cm depth. The tablets were carefully crushed and sieved to remove any fines and over-size particles. The resulting granulate, with a particle size between 0.2 and 0.6 mm flowed readily and evenly, did not clump together on shaking or stirring, and was free from a tendency to dust. On being rapidly added to 100 times its own weight of stirred distilled water, the particles dispersed readily and became fully hydrated within 30-60 minutes to give a translucent viscous mucilage which retained much of the air entrained within it during the mixing.
Comparison mixtures were prepared from the same batch of Carbopol 980 using conventional techniques as follows:
a) by adding the powder carefully to the distilled water to avoid lumping as the powder came into contact with the water. Some dusting of the powder was noted. The time taken for the powder to hydrate fully was again between 30 and 60 minutes and a similar mucilage resulted as that described above.
b) the powder was added at the same rate as the granulate. More dusting was observed and a number of large agglomerates were formed. These took many hours to fully wet out and hydrate. When the hydration was complete the mucilage was similar to that produced by method (a) above.
100 g of Carbomer 940 in a rotating plate granulator was sprayed with water until agglomeration started. Approximately 6 ml was needed to reach this point, the process was continued until the particle size had increased to about 1 mm. The resulting granules were free-flowing and non-dusting. When added rapidly to stirred demineralised water, they rapidly dispersed and then hydrated within approximately 30 minutes to give a viscous translucent mucilage.
The examples given above clearly indicate that the granulation of the carbomer allows the carbomer to be added to the water at faster flows, at a more economic flow rate whilst ensuring that a usable mucilage is obtained. This faster flow rate is achieved by the granulation of the carbomer and the end result can only be equalled using conventional carbomers if the carbomer powder is added extremely slowly in an attempt to prevent lumping occuring. Attempts to add the powder at the same rate as the granules results in a substandard mucilage being produced.
Further advantages are obtained in that the dusting problem experienced using conventional techniques is eliminated by granulation and the health and safety problems associated therewith are eliminated.
Additionally, small levels of electrolytes may be added to improve further the mixing characteristic of the granules, pellets or tablets with the liquid medium form the gel and the following are examples using this process.
100 grams of Carbopol 940, a fine powder with a particle size range of about 1 to 5 microns, was placed in a rotating plate wet granulator and the machine switched on. There was gradually added 10 ml of a 20% w/v solution of magnesium sulphate heptahydrate by spraying. The liquid was rapidly absorbed by the Carbopol and the mixture became granular within a short time, the granular product was then removed and passed through a sieve having 12 mesh openings/linear inch. 2.5 grams of the material which passed through the sieve was very rapidly added to a beaker containing 500 ml of distilled water of room temperature while it was being stirred. The granules immediately dispersed without lumping together and over 30 minutes swelled to give a homogeneous low viscosity hazy solution which rapidly de-aerated when the stirrer was switched off. Sodium hydroxide solution was added to this solution until a stable pH value of 7.2 was reached. The viscosity, measured on a Brookfield RVT viscometer at 20 rpm, of the brilliantly clear bubble-free gel was 46000 cps.
For comparison purposes a 0.5% solution of the same batch of Carbopol 940 was made directly from the powder using the same technique. The powder was rapidly tipped into the water whereupon severe lumping occurred and these lumps took several hours to fully hydrate to give a homogeneous mix. This solution did not allow the air entrained to rise out when stirring was stopped and when brought to a pH value of 7.2 contained many bubbles although it was otherwise as clear as the sample made from the granulated form. The viscosity measured in the same manner as before was 49000 cps
Similarly a sample of Carbopol 940 was dry blended with 2% of its weight of desiccated sodium sulphate, and dry granulated by compression. The coarse product was sieved to remove fines and particles larger than 10 mesh, and the rejected material was returned for further working. The residual material was then tested.
The viscosity of the un-neutralised Carbopol was nearly the same as water and since it did not exhibit any significant yield value the air which had been entrained in the solution rapidly rose to the surface so that upon neutralisation the gel formed was completely free of air bubbles.
A further trial using 0.8% magnesium sulphate in place of the sodium sulphate and the same batch of Carbopol 940 gave:
Blends of Carbopol 940 with 8% malic acid, and 0.6% sulphamic acid were prepared and gave:
It is clear that the increased addition of malic acid needed to reach the low un-neutralised viscosity has raised the overall electrolyte level to a point where a marked loss of viscosity has occurred after neutralisation, whereas there is virtually no loss of viscosity in the sample in which sulphamic acid was used. Because the malic acid, pK=3.4, is a much weaker acid than sulphanic acid (pK=1.92), much more is needed to effect the reduction in viscosity of the un-neutralised dispersion.
Other suitable acids include
Benzene-sulphonic acid
Citric acid
cyclo-propane-1,1-di-carboxylic acid
tartaric acid
however this listing is not intended to be exhaustive.
From these examples, it can be clearly seen that the addition of an electrolyte to the carbomer, provides an acidic dispersion which has a lower viscosity and hence can again be granulated, pelletised or formed into tablets and supplied to the users in that form whilst maintaining an adequate rate of hydration comparable with the powders currently available. The addition of the said electrolyte to the carbomer in the acid form, as opposed to after neutralisation, is inventive and novel in its own right. The proportion of said electrolyte should not be so high as to seriously reduce the viscosity of the neutralised gel formed by dispersion of the granulate in water and adding sufficient alkali to reach the required pH value which will normally be in the range of 5.0-8.5 but may for specific purposes be outside this range. It is also envisaged that the controlled addition of acid over and above that needed to achieve the effect of reducing the viscosity of the un-neutralised dispersion can be used as a means of reducing the batch to batch variation of these polymers when neutralised and, furthermore, to bring said batches which have a viscosity above the specified limit into specification. A further aspect of the invention therefore allows the manufacturer or user of the material to adjust and take into account any variation which may occur in the un-neutralised dispersion when hydrated.
It is known that the viscosity of carbomer dispersions in the acid form can be reduced in viscosity by the addition of acid in small proportion and hydrochloric acid and phosphoric acid have been suggested. Blending with the carbomer before addition to the water is a novel concept and the suggested acids would obviously be totally unsuitable in any case. Addition of electrolytes in the specific form of sodium salt of ethylene diamine-terra-acetic acid has also been recommended for controlling the viscosity of finished products by addition at the end of the process.
A specific embodiment of an industrial granulation technique to form the granules of the invention is now described with reference to the accompanying drawings wherein;