An improved method and means for eliminating scratches and other mechanical surface damage from polycarbonate compact disc plastic surfaces. The method consists in applying a liquid of suitable composition to the surface of a compact disc or plastic object, allowing an average of 10 seconds or less for the solvent to soften the plastic substrate, and removing the liquid by draining and evaporation. No abrasive, filler or polishing compounds are required. Suitable liquids include those comprising a solvent for the plastic and a non-solvent diluent and a small quantity of surfactant.

This invention relates in general to removing scratches from plastic surfaces, and in particular to a method and means which restores such discs damaged due to scratches and other surface imperfections.
This invention relates to producing smooth surfaces on substrates of plastic materials. In particular it provides a method for repairing damage due to scratches or other imperfections on the surface of plastic storage media for digitally encoded information of the type commonly embodied in so-called Compact Discs or CDs. Compact discs or CDs as they are commonly called, are optically encoded digital storage media. The physical structure of the disc is composed of a polycarbonate plastic known under the trade name of Lexan TM, a product of General Electric Corporation. Fabrication of a CD is accomplished by injecting molten polycarbonate into a cavity where micro pits are formed which represent encoded information. These micro pits are arranged in spiral data track. The side where the micro pit track has been formed is coated with a thin layer deposition of metal, usually aluminum or gold, to make the surface reflective. Subsequent treatment involves adding a lacquer coating over the delicate reflective surface as a protective layer followed by a silk screened label.
The polycarbonate is used both as a support structure and as an optical window through which a laser is focused on the reflective layer containing the data tracks. Each pit in the track varies in length according to the encoded digital data. Depending on whether the laser light is scattered or reflected back is related to pit presence and length and provides the basis for recovering a digital data stream which represents the desired recorded information.
Anything which interferes with the ability of the laser scanning system to focus on the encoded pits can lead to data loss. Scratches, debris and even oil deposits from finger prints all have the potential to cause such data interruption. To minimize the effect of minor laser obstruction, CD playback systems typically employ an electronic data interpretation algorithm which can recover lost information.
Despite error correction schemes, ordinary handling of compact discs can lead to minor or severe mechanical surface damage as a result of contact with abrasive particulate matter or by simply allowing one CD to be placed in sliding physical contact with another CD. Accumulation of this damage can exceed the error correction capabilities of the CD reader hardware and software, especially if a scratch or combination of scratches occurs in a curvilinear rather than a radial orientation. Due to the sequential nature of the encoded data, such damage renders vast amounts of information unavailable for error correction, ultimately rendering the optical disc useless. The net effect is a costly loss of data such as in CD ROM library databanks. The only recourse left to the user faced with such damage is the purchase of a replacement disc, if available.
Since the compact disc is fabricated from plastic, means used to polish plastic have been attempted in an effort to remove scratches and other surface imperfections. There have been a variety of attempts to develop procedures that will remove scratches and other mechanical surface defects from CDs. Many of the proposed approaches involve polishing with fine abrasives dispersed in a lubricant to remove surface irregularities, sometimes with a deformable material to fill in unwanted scratches or pits. For example, U.S. Pat. Nos. 5,334,335, 5,337,524 and 5,407,615 issued to W. C. Norville, disclose various formulations of abrasives, solvents, fillers and lubricants designed to abrade surface projections and fill in pits and scratches in plastic surfaces including compact discs. However, it is difficult to produce a smooth surface finish on polymeric materials by abrasion, in part because they are too soft and flexible to abrade readily and in part because they are not good thermal conductors and therefore do not dissipate frictional heat very effectively. The resulting temperature rise can soften the plastic and result in gumming and poor finish control, as discussed in Modem Plastics Encyclopedia, pp. 533-536, S. Gross, Editor-in-Chief (McGraw-Hill, N.Y., 1974). Also to be remembered in the case of CDs is that removal of material from the surface of the disc by abrasion or polishing can cause permanent local variations in disc thickness. Thickness irregularities can result in focus error and data loss. Furthermore, any filling of pits and scratches can also cause data loss due to possible laser scatter at the transitional interface between the plastic media and a filler agent.
U.S. Pat. Nos. 4,654,917 and 4,783,870 to C. K. Yeung disclose an apparatus that combines rotation of a CD with radial motion of a pad so that the entire surface of the disk can be evenly rubbed by the pad, after it is soaked with a cleaning solution, to remove fingerprints, oil deposits, and dust particulates or other debris. Neither disclosure offers a means to rectify the deleterious effects of scratches or other disc surface damage.
International Application WO 95/21890 by M. J. Smithlin, published on Aug. 17, 1995, also describes a composition and a method for repairing a CD. The composition comprises a mixture of a wax with a refractive index which approximates that of CD polycarbonate, a solvent for the wax, some fine abrasive material and an emulsifier to keep the abrasive in suspension. The solvent must be one that does not soften or dissolve the disc material. A small amount of the mixture in paste or liquid form is applied to the disc surface and gently rubbed with a soft cloth or other applicator until the defect is smoothed and filled. The disc is considered repaired when examination with a microscope indicates that the edges of the scratch are beveled or rounded and the scratch is filled with the composition. It should be noted that this method does not remove particulate matter produced as the result of a scratch or other surface damage or take into account that surface damage often has light scattering effects not addressed by a filler agent. Further, this method must be considered as a temporary repair because such filler can often be easily dislodged.
Several investigators have taken a different approach in which the plastic is softened in a controllable manner so that surface tension forces can reduce the surface area, thereby smoothing surface projections and scratches. D. Duchane in U.S. Pat. No. 4,376,751 and in an article in Materials Engineering, vol. 9, No. 4, p 68 (1981) decribes a method in which the object with a plastic surface is immersed in a solution of solvent in a non-solvent diluent. Over a period of hours the concentration of solvent in non-solvent diluent is slowly decreased to zero. This procedure is intricate, lengthy, and consumes a substantial amount of solvent per treatment. Further, a significant amount of nonsolvent may be permanently incorporated into the polymeric article, an undesirable result in the case of a CD. The process assumes that a slow removal of solvent is necessary to prevent recurrence of the surface defects. Indeed, Duchane has asserted that xe2x80x9cmethods in which solvent is allowed to evaporate from a plastic surface are so fast that surface wrinkling occurs.xe2x80x9d(Chemical Engineering, Nov. 25, 1985, page 15.)
U.S. Pat. No. 4,260,873 to M. R. Simmonds and U.S. Pat. No. 5,448,638 to Edmonds both describe a method in which heated solvent vapor partially dissolves a plastic surface, softening it sufficiently so that surface tension forces will tend to decrease the surface area and thus smooth the plastic surface. A fairly complex and expensive apparatus is required and it is difficult to control the extent of vapor penetration by manipulating the vapor pressure, temperature and duration of exposure, so as to preclude crazing and stress cracking.
U.S. Pat. No. 4,302,418 to Cullis discloses a process where a fluid medium is used for polishing plastic surfaces made of a material which is insoluble or inert within that fluid medium unless subjected to a temperature at which plastic deformation would occur. The process includes employing a solvent vapor at an elevated pressure to liquefy a plastic surface without causing total plastic component deformation. This method requires complex temperature and pressure regulation and can result in stress crazing of plastic media or could cause a transparent plastic media to become opaque. Further, use of solvent vapor will render a plastic surface susceptible to contamination by dust or particulate matter when can become permanently embedded on the surface of the plastic media being treated. Finally, the required apparatus is expensive and the process is time consuming.
Examination of the prior art as set forth in the cited references indicates that all of the previously proposed methods for producing smooth surfaces on plastic materials comprise fairly slow and complex procedures and are not particularly effective. By contrast the method of the present invention achieves the same objectives by a procedure that is simple, rapid, uses minimal amounts of reagents and requires no special apparatus.
The present invention permits scratch and minor surface imperfections of plastics to be substantially reduced or eliminated by the simple application of an appropriately diluted solvent solution. A small amount of restoring liquid having a suitable composition is applied to the damaged surface. The excess liquid is wiped off and residual liquid is permitted to evaporate. The whole procedure, from application of the restoring liquid until the plastic surface is smoothed, requires only seconds. The key discovery underlying the invention relates to the xe2x80x9csuitable compositionxe2x80x9d of the restoring liquid. It must comprise a mixture of which at least one component species is a solvent capable of dissolving or substantially softening the plastic surface to be repaired. The liquid must also comprise one or more non-solvent components which serve to dilute the solvent component, thereby reducing its dissolving activity or rate. When the restoring liquid contains the right proportions of these components its application and subsequent removal by wiping and evaporation will result in a smooth surface essentially free of undesirable scratches or other surface imperfections.
One object of the invention is to restore to its original smoothness, the marred surface of an article whose outermost layer comprises a polymeric substance of the type commonly characterized as a xe2x80x9cplasticxe2x80x9d or xe2x80x9cthermoplasticxe2x80x9d material.
Another object of the invention is to provide a simple, safe, rapid, convenient and inexpensive means of smoothing the surface of plastic objects.
Another, and particular, object of the invention is to provide a means of restoring to useful operability a thermoplastic recording medium such as a Compact Disc or CD whose surface has been damaged by scratches so that optical distortion, and/or reduction of transparency of the media prevents adequate recovery of encoded information.
Still other objectives and possible applications of the invention will become evident to those knowledgeable in the related arts.

Method and means of restoring physically damaged compact discs

c/o Conn. Analytical Corp., 696 Amity Rd.


An apparatus and method for increasing storage capacity of granular material storage structures. The apparatus includes a curtain assembly supportable from the roof structure of the granular material storage structure and above the sidewalls thereby defining a second volume within which the granular material may be filled which is above the first volume defined by the interior volume of the sidewalls and the volume defined by the angle of repose of the granular material.

With the growing popularity of ethanol and bio-diesel driving up prices of corn and soybeans, crop producers are planting more and more acres of these crops. Furthermore, with advances in seed genetics and new hybrids, yields continue to improve. The combination of these two factors has resulted in a shortage of storage facilities during the harvest season at grain elevators and refineries that produce ethanol and soy-diesel. To address the storage facility shortage, temporary or semi-permanent ground storage structures have become increasingly popular due to their relative low cost as compared to conventional grain elevators, silos or bins.
Ground storage structures generally comprise a concrete slab-on-grade surrounded by vertical sidewalls constructed of concrete, steel or timber. These ground storage structures are typically covered with a light-weight roof structure to protect the grain from the environment to minimize spoilage. The roof structures are generally comprised of steel trusses supporting fabric or plastic sheeting. The roof trusses are generally arcuate or curvilinear, but may be any other configuration, including gable or hip configurations, or any other configuration and material suitable for the span and loading conditions in the area as dictated by applicable building codes or sound engineering practices.
In addition to storing grain, ground storage structures are also commonly used for bulk storage of other granular materials for which it is desired to minimize exposure to the environment, such as, for example, road salt used in northern climates during winter months to de-ice roads and improve traction.
It should be appreciated that the majority of the cost of such semi-permanent storage structures is associated with the sidewalls of the structure, whether concrete, steel or timber. Thus, it is desirable to provide a system and method to increase the storage capacity of existing structures to avoid the need for new construction and to reduce the cost per unit of storage volume for such storage structures.

Apparatus and system to increase capacity of granular material storage structures


The present invention provides a highly efficient, ceramic foam material for filtering molten metal which is characterized by improved strength reliability. The filter of the present invention is prepared by impregnating an organic foam material with an aqueous ceramic slurry containing ceramic fibers. In accordance with the present invention it has been found that it is possible to prepare a low cost, porous ceramic filtration medium having improved strength reliability.

Molten aluminum in practice generally contains entrained solids which are deleterious to the final cast metal product. These entrained solids usually derive from three sources. Some are particles of aluminum oxide which are drawn into the liquid stream from the floating oxide layer on its surface, and some entrained particles are fragments of furnace lining, transfer trough and other portions of the molten aluminum handling equipment which are eroded and entrained in the flowing aluminum stream, and some particles are precipitates of insoluble impurities such as intermetallics, borides, carbides or precipitates of other aluminum compounds, such as chlorides. When these inclusions appear in the final cast product after the molten aluminum is solidified, they cause such final product to be less ductile or to have poor finishing characteristics. Accordingly, it is desirable to remove entrained solids from the molten aluminum stream before it is cast into a solid body which may be used as such or subjected to forming operations such as rolling, forging, extrusion, etc.
Filtering processes to remove entrained solids from liquids are accomplished by passing the solid-laden liquid through a porous filter medium that will not pass the solids. Filtering molten metal in general, and molten aluminum in particular, creates special problems because the liquid is so aggressive that it is difficult to find a filter medium capable of withstanding it.
In general, two methods of filtering are used for removing entrained solids from molten aluminum alloys before casting. The most common filter medium is an open weave glass cloth screen placed in the metal transfer trough, around the spout or even in the molten metal pool in the top of the solidifying ingot. These cloth screens are able to remove only the larger sizes of inclusions from the metal and are easily ruptured during use because the glass fibers become very weak at the temperature of molten aluminum. In another prior art procedure, molten aluminum is filtered through a bed of loose alumina particles, for example, of tabular alumina, but it often suffers from the drawbacks normally associated with bed filters in that it passes too many solids, there is a strong tendency to channeling which prevents efficient use, and pore size of the filter is not easily controlled but rather readily changes under conditions of use so that, even when originally of proper dimension, it cannot be efficiently maintained. In addition, the metal must be kept constantly molten when the filter is not in use.
An improved method for filtering and removing entrained solids from molten aluminum alloys is disclosed in U.S. Pat. No. 3,893,917, assigned to the assignee of the instant invention, and employs a ceramic foam filter having an open cell structure characterized by a plurality of interconnected voids surrounded by a web of ceramic. While the use of the ceramic foam filter greatly increases filtration efficiency there is a problem with the strength reliability of the filter element.
Accordingly, it is a principal object of the present invention to provide an improved molten metal filter and a method for preparing same and also a method for filtering molten metal therethrough.
It is an additional object of the present invention to provide a filter and method as aforesaid wherein said filter has improved strength reliability.
A further object of the present invention is to obtain a filter and method as aforesaid which obtains high filtration efficiency.
Further objects and advantages of the present invention will appear hereinafter.


The present invention relates to substantially pure poly(arylene ether), e.g. purities exceeding about 99%, and to a method for making the same. The method which eliminates multiple rinses with a complexing reagent includes removing the catalyst from the polymerization mixture by mixing the polymerization mixture with a complexing reagent and liquid/liquid centrifuging the multiphase mixture. Water is then added to the polymer phase prior to a subsequent liquid/liquid centrifuge process. Once the catalyst has been sufficiently removed, the polymer can be concentrated in a flash vessel (which is not heated) by introducing a heated polymer phase to the vessel at a high pressure and quickly reducing the pressure. The concentrated polymer can then be introduced to an extruder to produce the high purity polymer. Due to the introduction of low molecular weight poly(arylene ether) at the intake zone of the extruder, essentially pure poly(arylene ether) can be isolated by this process. By combining the extruder process with an underwater pelletizer, thus providing extremely rapid cooling of the polymer melt when it exits the extruder and contacts air, much better color and lower amount of black specs in the final product is obtained.

The present invention relates to a method for making poly(arylene ether), and especially relates to a method for making substantially pure polyphenylene ether.
Poly(arylene ether) constitutes a large class of polymers which are employed pure or as blends in a wide variety of applications in the automotive, liquid handling and electronics industries. Poly(arylene ethers) are formed by reacting the monomer, either phenol or a substituted phenol, dissolved in an organic solvent, with oxygen in the presence of a catalyst. Copper-amine complexes are the most widely used catalysts for these reactions, although there are several other catalysts known in the art. Catalysts generally contain at least one heavy transition metal compound such as copper, manganese or cobalt compound, usually in combination with various other materials. Catalyst compounds can either be soluble in the reaction solvent or in solid form, i.e. supported on a solid substrate like silica, alumina or other insoluble support materials. Such catalysts are disclosed, for example, in U.S. Pat. Nos. 3,306,874, 3,306,875, 3,914,266 and 4,028,341 which are incorporated by reference herein.
The end point of the polymerization reaction is controlled by a number of methods known in the art such as in-line viscometry, molecular weight measurement, reaction run time, endgroup content, or oxygen concentration or oxygen consumption. When the end point is reached the polymerization reaction is stopped by halting addition of the oxygen reactant or removing the catalyst.
Several methods of catalyst removal are known in the art, most involving the use of an aqueous solution of a complexing agent. When the aqueous solution is added to the organic solution of the polymerization reaction two phases result. The complexing agent reacts with the catalyst and makes the resulting complex soluble in the aqueous phase (catalyst phase). The catalyst and poly(arylene ether) phases must then be separated and the poly(arylene ether) phase is carried on for isolation.
Good phase separation is essential to producing good quality poly(arylene ether). Without good phase separation the organic layer retains a significant amount of copper. Residual copper has an adverse affect on the properties of the polymer, with the sensitivity to oxidation and the inherent color particularly affected. Poly(arylene ether) oxidation causes black specs in most types of poly(arylene ether) processing such as extrusion and injection molding. German Patent Application No. 2,640,147 discloses improved phase separation through the use of an alcohol containing diluent. This method however has several disadvantages: the complexing reaction and the diluent addition require separate mixing units, a large amount of alcohol is required and the resulting copper containing solution is very dilute which complicates waste treatment. Other approaches to improved phase separation rely on anionic, cationic or non-ionic surfactants and de-emulgators. A de-emulgator is a substance that de-stabilizes an emulsion, allowing the resulting phases to be separated.
An alternate approach to catalyst removal, as disclosed in U.S. Pat. No. 4,654,418, involves a series of mixer-settler stages. The reaction mixture is combined with an aqueous complexing agent solution in a mixing stage, sent to a settler where the phases are separated and the process is repeated with additional aqueous complexing agent solution. The aqueous complexing agent solution is recycled from the second step to the first step, which improves the overall organic to aqueous phase ratio of 1.0:0.2-1.0:0.8, but increases the complexity of the apparatus. The resulting polyphenylene ether solution has a copper content less than 1 mg/kg and can be isolated using methods known in the art such as spray drying, steam precipitation, crumb formation with hot water, and multi stage devolatization.
Multistage devolatization is the most economically advantageous method of isolation because the isolation and extrusion are handled all in one step. However, there are numerable difficulties. The typically high solvent load to the extruder causes vent plugging and decreases operational stability. A low viscosity polymer, like polystyrene, is required to form a melt seal at the throat of the extruder to prevent toluene from being vented into the atmosphere. Thus the resulting poly(arylene ether) resins contain the low viscosity polymer which reduces the glass transition temperature and the viscosity of the final product. The poly(arylene ether) resin isolated by multistage devolatization frequently has high color and a high incidence of black specs. Good quality poly(arylene ether) resin has low color (a low yellowness index (YI)) and a low incidence of black specs. The color, as well as processing stability, can be improved by the addition of a thermal/oxidative stabilizer, such as hindered phenol or phosphites. Use of stabilizers increases the number of steps in the manufacturing process and the cost. Although multistage devolatization is economically advantageous it has not reached its full potential due to processing and color issues.
Accordingly, there remains a continuing need in the art for a method to produce substantially pure poly(arylene ether) with good processing stability, low color and a low incidence of black specs.
The above discussed drawbacks and deficiencies of the prior art are overcome or alleviated by the method of the present invention. The present invention relates to an improved process for producing substantially pure poly(arylene ether) comprising: a.) a process for removing the catalyst from a poly(arylene ether) polymerization reaction comprising adding a polar liquid and centrifuging, and b.) isolating the poly(arylene ether) polymer from the reaction mixture without the addition of a low viscosity polymer other than poly(arylene ether). Isolation of the poly(arylene ether) polymer comprises an optional concentration step and a method of using a devolatizing extruder.
Not Applicable
The above discussed drawbacks and deficiencies of the prior art are overcome or alleviated by the method of the present invention. The present invention relates to an improved process for producing substantially pure poly(arylene ether) comprising: a.) a process for removing the catalyst from a poly(arylene ether) polymerization reaction comprising adding a polar liquid and centrifuging, and b.) isolating the poly(arylene ether) polymer from the reaction mixture without the addition of a low viscosity polymer other than the poly(arylene ether) that is being isolated. Isolation of the poly(arylene ether) polymer comprises an optional concentration step and a method of using a devolatizing extruder.
The process of removing catalyst from a poly(arylene ether) polymerization reaction comprises: a) adding at least one polar solution to the reaction mixture to form a first at least two phase mixture, wherein one phase of said first at least two phase mixture is a polymer phase; b) liquid/liquid centrifuging said first at least two phase mixture to separate the phases; c) removing said polymer phase from said first at least two phase mixture; d) adding water to said polymer phase to form a second at least two phase mixture, where one phase of said second at least two phase mixture is a second polymer phase; e) separating said second polymer phase from said second at least two phase mixture.
The invention further relates to a process for isolating the poly(arylene ether) from the polymer phase. The isolation process can include a process for concentrating a mixture, comprising: heating the mixture at a first pressure; introducing the mixture to a vessel, wherein said vessel is at ambient temperature or cooled; and flashing the mixture to a second pressure lower than said first pressure and greater than atmospheric pressure. Either following the concentration step or immediately following catalyst removal, isolation can be completed in a devolatizing extruder.
The invention further relates to a method of utilizing a devolatizing extruder. Low molecular weight (low intrinsic viscosity) poly(arylene ether) is added to the intake feed of the extruder to form a melt seal. This is in contrast to the prior art practice of using low molecular weight polymers other than poly(arylene ether) such as polystyrene.
Poly(arylene ether)s are known polymers comprising a plurality of structural units of the formula (I):
wherein for each structural unit, each Q1 is independently halogen, primary or secondary lower alkyl (e.g., alkyl containing up to 7 carbon atoms), phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, or halohydrocarbonoxy wherein at least two carbon atoms separate the halogen and oxygen atoms; and each Q2 is independently hydrogen, halogen, primary or secondary lower alkyl, phenyl, haloalkyl, hydrocarbonoxy or halohydrocarbonoxy as defined for Q1. Preferably, each Q1 is alkyl or phenyl, especially C1-4 alkyl, and each Q2 is hydrogen.
Both homopolymer and copolymer poly(arylene ether)s are included. The preferred homopolymers are those containing 2,6-dimethylphenylene ether units. Suitable copolymers include random copolymers containing, for example, such units in combination with 2,3,6-trimethyl-1,4-phenylene ether units or copolymers derived from copolymerization of 2,6-dimethylphenol with 2,3,6-trimethylphenol. Also included are poly(arylene ether) containing moieties prepared by grafting vinyl monomers or polymers such as polystyrenes, as well as coupled poly(arylene ether) in which coupling agents such as low molecular weight polycarbonates, quinones, heterocycles and formals undergo reaction in known manner with the hydroxy groups of two poly(arylene ether) chains to produce a higher molecular weight polymer and also included are all chemically modified poly(arylene ethers) such as endgroup modified or grafting modified polymers. Poly(arylene ether)s further include combinations of any of the above.
Poly(arylene ether) is formed from precursors, typically monomers, such as 2,6-dimethylphenol, 2,3,6-trimethylphenol, orthocresol or any other substituted or unsubstituted phenols. It will be apparent to those skilled in the art from the foregoing that the poly(arylene ether) contemplated for use in the present invention include all those presently known, irrespective of variations in structural units or ancillary chemical features.
Formation of poly(arylene ether) by a polymerization reaction is carried out by the continuous addition of oxygen to a reaction mixture containing a solvent, the chosen monomer or monomers, and a catalyst. The oxygen can be supplied via any oxygen source, such as air, pure oxygen gas or any other oxidative species.
The catalyst can comprise any conventional catalyst capable of facilitating polymerization and formation of the poly(arylene ether), with transition metal complexes typically employed. Typically the transition metal comprises copper, manganese or cobalt, with cooper preferred. Such catalysts are disclosed, for example, in U.S. Pat. Nos. 3,306,874, 3,306,875, 3,914,266 and 4,028,341 which are incorporated by reference herein. Copper-amine complexes are especially preferred and are formed in situ from a copper salt solution, preferably cuprous bromide, and an amine mixture, typically of secondary and tertiary amines, and preferably dibutylethyleneamine, dibutylamine, dimethylbutylamine, a quaternary ammonium salt, mixtures comprising at least one of the foregoing amines, and others.
When the monomer or monomers have been polymerized to the desired degree, preferably a solids concentration greater than about 20%, and more preferably greater than about 22%, as determined by any known method in the art, the catalyst is removed from the mixture.
Removal of the catalyst is achieved by a combination of the introduction of a polar liquid to the mixture to form multiple phases, and performing liquid-liquid centrifuging. When the polar liquid is added to a poly(arylene ether) reaction solution, the copper-amine catalyst becomes inactivated, halting further oxidation. The polar liquid can be water, a solution of a complexing reagent, also known as a chelating agent, or a combination thereof. Many diverse complexing agents may be used, such as sulfuric acid, acetic acid, ammonium salts, bisulfate salts, and the like, as well as mixtures comprising at least one of the foregoing complexing agents, with those disclosed in U.S. Pat. No. 3,838,102 to Bennet et al, which is herein incorporated by reference, preferred. Some preferred complexing agents include polyfunctional carboxylic acid containing compounds such as, for example, sodium potassium tartrate, nitrilotriacetic acid (NTA), citric acid, glycine, and the like with polyalkylenepolyamine polycarboxylic acids, aminopolycarboxylic acids, aminocarboxylic acids, aminopolycarboxylic acids, aminocarboxylic acids, polycarboxylic acids and their alkali metal, alkaline earth metal or mixed alkali metal-alkaline earth metal salts, and the like, preferred. Other preferred agents include hydroxyethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid and their salts; and ethylenediaminotetraacetic acid (EDTA) and a mono-, di-, tri- or tetrasodium salts thereof. Also useful are combinations comprising at least one of any of the above complexing agents. The complexing endgroup to copper catalyst molar ratio is preferably about 1:1 or higher. The complexing endgroup is that part of the complexing agent which reacts directly with the catalyst.
The multiphases are preferably mixed and allowed to reach equilibrium (e.g., for up to about 70 min.) at a temperature which facilitates separation of the phases and removal of the catalyst. Although room temperature (e.g., about 25xc2x0 C.) is acceptable, heating the phases up to about 50xc2x0 C. or greater is preferred. Importantly, the temperature preferably is below the boiling point of the components. Prior to feeding to the centrifuge, water may be added to the mixture. Separation of the phases is then facilitated with a liquid/liquid centrifuge. The centrifuging step can be repeated until the desired removal is attained. Useful centrifuges include both batch and continuous centrifuges, with continuous centrifuges preferred.
For example, a solution of nitrilotriacetic acid is added to the catalyst-poly(arylene ether) mixture. The mixture is heated to about 55xc2x0 C., equilibrated for 70 minutes and liquid/liquid (L/L) centrifuged in a continuous centrifuge at about 4,500 rpm. The aqueous catalyst phase is drawn off and the separated organic poly(arylene ether) solution phase, preferably mixed with water, is fed to a second continuous liquid/liquid centrifuge operating at about 6,000 rpm. Again, the polymer phase is removed. The combination of using the liquid/liquid centrifuge with a polar liquid unexpectedly resulted in a polymer phase containing less than about 5 per million (ppm) catalyst, typically less than about 2 ppm catalyst, and preferably less than about 1.1 ppm catalyst. It was further discovered that, in contrast to conventional catalyst removal techniques, multiple introductions of the chelating agent was not necessary to obtain such high catalyst removal from the polymer phase. Catalyst removal to less than about 1.1 ppm could be obtained using a first centrifuging with a chelating agent and a second centrifuging with water, preferably distilled water.
The polymer phase, after catalyst removal, can be concentrated so as to increase the solids content of the polymer phase and reduce the solvent load to the devolatizing extruder thereby improving extruder performance. Concentration comprises preheating the polymer phase to a temperature so that the sensible heat content of the polymer phase is sufficient to supply the needed latent heat for the evaporation of the organic solvent at a pressure sufficiently high to prevent flashing in the heat exchanger or lines before the flash valve and flash vessel. Sensible heat of the polymer phase is the thermal energy supplied to the polymer solution to increase the temperature of the phase; this is in contrast to heat needed for evaporating the solvent, which is called the latent heat of vaporization. Both forms of heat or energy add up to the total heat content of the polymer phase. Once the polymer phase has attained the desired temperature and pressure, it is flashed to a lower pressure without heating the flash vessel. The pressure in the flash vessel determines the corresponding solvent vapor/liquid (V/L) equilibrium temperature. The temperature difference before and after the flash vessel determines the total amount of solvent evaporated and hence the residual poly(arylene ether) concentration of the flashed solution. Typically the pressure of the flash vessel is chosen such that there is a slight overpressure in the vessel, preferably from about 1.05 bar to about 1.4 bar, in order to limit the risk of air leakage from outside the flash vessel.
In a preferred embodiment, the polymer phase is concentrated to obtain a target solid poly(arylene ether) content. Preferably the target solid poly(arylene ether) content is about 55% to about 75% and more preferably from about 65% to about 75%. The temperature of the polymer phase prior to flashing is preferably about 235xc2x0 C. to about 255xc2x0 C. and more preferably from about 240xc2x0 C. to about 250xc2x0 C. The pressure of the polymer phase prior to flashing is preferably from about 35 bar to about 45 bar and more preferably from about 40 to about 45 bar. Optionally, the mixture resulting from the initial concentration step can be directed to a buffer tank and the concentration step repeated to increase the percentage of solids.
Conventionally flash vessels are heated and a lubricant (which reduces the purity of the final polymer), such as a low molecular wax, is added to the polymer phase to prevent sticking of the flashed concentrate to the vessel wall. It was unexpectedly discovered that the lubricant is not necessary if the flash vessel is unheated or even cooled and the pressure of the flash vessel is maintained at slightly above atmospheric pressure, preferably from about 1.05 bar to about 1.4 bar.
Isolation is preferably performed in a devolatizing extruder although other methods such as wiped film or thin film evaporators are acceptable. The polymer phase may be isolated after catalyst removal and concentration or directly after catalyst removal. Preferably, the devolatizing extruder comprises co-rotating intermeshing screws, an intake zone, a back-feed capability, a sufficient amount of devolatizing venting sections (e.g., preferably more than 2, with about 4 or more especially preferred) and a solution feed between at least two of the venting sections. A feed between the first and second venting sections is especially preferred. The screw, preferably operating at a speed between about 250 rpm and about 300 rpm, moves the polymer through the extruder via transport elements which are preferably self wiping. The devolatizing extruder more preferably comprises an intake zone comprising a feed port, kneading section and vacuum vent, followed by a solution feed port and three vacuum vents with kneading sections in between. The devolatizing extruder is capable of heating to temperatures greater than about 300xc2x0 C. and is capable of maintaining different temperatures and pressures in different sections of the extruder.
In a preferred embodiment of the invention, about 0.1 weight percent (wt %) to about 1.0 wt % low molecular weight poly(arylene ether), in pellet form, is added at the intake zone of the devolatizing extruder. The low molecular weight poly(arylene ether) preferably has an intrinsic viscosity of about 0.09 dl/g to about 0.16 dl/g. The low molecular weight poly(arylene ether) forms a melt seal which inhibits the solvent from being vented into the atmosphere and prevents sticking in the first zones of the extruder without reducing the purity of the poly(arylene ether). The low molecular weight poly(arylene ether) is melted, compounded, and degassed. The polymer phase is then added, preferably after concentration, and the polymer phase is intimately mixed with the low molecular weight poly(arylene ether) and solvent removed via incremental increases in temperature and incremental decreases in pressure. The temperature of the extruder is about 240xc2x0 C. to about 300xc2x0 C. The minimum pressure is as low as can be reasonably attained, preferably about 0.1. bar to about 0.4 bar. The operating conditions of the devolatizing extruder are readily determined without undue experimentation by one of ordinary skill in the art.
The combination of incremental temperature increases combined with incremental pressure decreases are commonly known as multi-stage devolatization. Unexpectedly the combination of concentration followed by multi-stage devolatization yields polymer with a very low solvent content, typically less than about 1,000 ppm, with less than about 800 ppm preferred, and less than about 600 ppm especially preferred.
The resulting polymer may be handled by any method known in the art, such as die face pelletization, flaking, strand pelletization, xe2x80x9cvibrating dropxe2x80x9d pelletization, sheet forming, web forming, as well as other conventional methods. Preferably, the extruded polymer is underwater pelletized. Drying of the pellets to low moisture contents can be conveniently carried out in several ways known in the art, including a centrifugal dryer, batch or continuous oven dryers, fluid bed dryers, and the like.
In another preferred embodiment the polymer phase is concentrated to a solids content of about 55% to about 75% and further isolated in a devolatizing extruder. In another embodiment, the polymer phase is flashed either partly or totally into the extruder. The polymer phase is heated to a temperature about 230xc2x0 C. to about 260xc2x0 C. preferably about 235xc2x0 C. to about 255xc2x0 C., and even more preferably about 240xc2x0 C. to about 250xc2x0 C. at a pressure of about 30 bar to about 50 bar, preferably about 35 bar to about 45 bar, and even more preferably about 40 bar to about 45 bar, prior to introduction to the extruder. Upon introduction to the extruder the pressure change, typically at least about 30 bar, flashes the polymer phase, increasing the solids content to about 55% or greater.
The invention is further illustrated by the following non-limiting example.

Poly(arylene ether) and process for making the same


A process for making composite colorant particles comprising, in order:

This invention relates to the preparation of composite colorant particles that have a colorant phase and a polymer phase, and more particularly to the preparation of composite particles which have a pigment phase and a polymer phase. The composite colorant particles are useful for forming ink jet inks for ink jet printing.
Ink jet printing is a non-impact method for producing images by the deposition of ink droplets on a substrate (paper, transparent film, fabric, etc.) in response to digital signals. Inkjet printers have found broad applications across markets ranging from industrial labeling to short run printing to desktop document and pictorial imaging.
In ink jet recording processes, it is necessary that the inks being used meet various performance requirements. Such performance requirements are generally more stringent than those for other liquid ink applications, such as for writing instruments (e.g., a fountain pen, felt pen, etc.). In particular, the following conditions are generally required for inks utilized in ink jet printing processes:
(1) The ink should possess physical properties such as viscosity, surface tension, and electric conductivity matching the discharging conditions of the printing apparatus, such as the driving voltage and driving frequency of a piezoelectric electric oscillator, the form and material of printhead orifices, the diameter of orifices, etc;
(2) The ink should be capable of being stored for a long period of time without causing clogging of printhead orifices during use;
(3) The ink should be quickly fixable onto recording media, such as paper, film, etc., such that the outlines of the resulting ink dots are smooth and there is minimal blotting of the dotted ink;
(4) The printed image should be of high quality, such as having a clear color tone and high density, have high gloss and high color gamut;
(5) The printed image should exhibit excellent waterfastness (water resistance) and lightfastness (light resistance);
(6) The printed (ink) images should have good adhesion to the surface of image receiving elements and should be durable and highly resistant to physical and mechanical scratches or damages
(7) The ink should not chemically attack, corrode or erode surrounding materials such as the ink storage container, printhead components, orifices, etc;
(8) The ink should not have an unpleasant odor and should not be toxic or inflammable; and
(9) The ink should exhibit low foaming and high pH stability characteristics.
The inks used in various ink jet printers can be classified as either dye-based or pigment-based. A dye is a colorant which is molecularly dispersed or solvated by a carrier medium. The carrier medium can be a liquid or a solid at room temperature. A commonly used carrier medium is water or a mixture of water and organic cosolvents. Each individual dye molecule is surrounded by molecules of the carrier medium. In dye-based inks, no particles are observable under the microscope. Although there have been many recent advances in the art of dye-based inkjet inks, such inks still suffer from deficiencies such as low optical densities on plain paper and poor lightfastness. When water is used as the carrier medium, such inks also generally suffer from poor waterfastness.
Pigment-based inks have been gaining in popularity as a means of addressing these limitations. In pigment-based inks, the colorant exists as discrete particles. These pigment particles are usually treated with addenda known as dispersants or stabilizers which serve to keep the pigment particles from agglomerating and/or settling out.
Pigment-based inks suffer from a different set of deficiencies than dye-based inks. One deficiency is that pigment-based inks interact differently with specially coated papers and films, such as transparent films used for overhead projection and glossy papers and opaque white films used for high quality graphics and pictorial output. In particular, it has been observed that pigment-based inks produce imaged areas that are entirely on the surface of coated papers and films which results in images that have poor dry and wet adhesion properties and can be easily smudged. In recent years, ink jet receivers have been developed to have both high gloss and fast drying capacities. However, scratch mark smudges are more visible on high gloss receivers. There is a need to provide a pigmented ink composition that results in images on the surface of an ink jet recording element which have improved durability and smudging resistance.
Another deficiency from which pigmented inks suffer is their poor storage stability due to the presence of a water-miscible organic solvent. Water-miscible organic solvents are used to adjust ink rheology, to maximize ink firability and re-runability. These solvents prevent ink from drying in a printing head and lower ink surface tension to minimize the effect of air-entrapment in an ink formulation which would otherwise generate air bubbles which would seriously affect the head performance. However, these water-miscible organic solvents can also have a negative effect on the colloidal stability of pigment particles in an ink formulation. There is a need to provide a pigmented ink composition which would have improved storage stability in the presence of various types of water-miscible organic solvents.
U.S. Pat. No. 5,852,073 discloses an erasable ink composition which comprises a dispersion of particles of water-insoluble polymer-encapsulated colorant obtained by polymerizing under emulsion polymerization conditions in the presence of solid colorant particles. The process described is a batch or semi-batch process by which an ethylenically-unsaturated monomer and a colorant are emulsified together before being subjected to emulsion polymerization conditions. The particle dispersions prepared by such a process are a physical mixture of polymer latex particles, polymer encapsulated colorant, and water soluble polymers. However, there is a problem with these dispersions when they are formulated into an ink jet ink, in that the presence of free polymers (both polymer particles and water soluble polymers) can significantly increase ink viscosity, decrease ink storage stability, cause premature printing head failure, and generate image defects.
EP1006161 discloses a process for making an ink composition wherein polymer-coated colorant particles are prepared using a batch emulsion polymerization process employing colorant particles, monomers and an initiator. The polymer-coated colorant particles prepared by such a process are a physical mixture of polymer particles, polymer-encapsulated colorant and water-soluble polymers. However, there is a problem with these dispersions when they are formulated into an ink jet ink, in that the presence of free polymers (both polymer particles and water soluble polymers) can significantly increase ink viscosity, decrease ink storage stability, cause premature printing head failure, and generate image defects.
It is an object of this invention to provide a method of preparing a colorant particle dispersion that has improved compatibility with water-soluble organic solvents, improved stability in an ink jet composition, and when such ink composition is printed, the resultant images on the surface of an ink jet recording element have improved image quality and physical durability such as scratch and smudging resistance.
These and other objects are achieved in accordance with this invention which relates to a process for making composite colorant particles comprising, in order:
I) suspending in an aqueous medium, under agitation, finely divided colorant particles to form an aqueous colorant mixture;
II) adding to the aqueous colorant mixture an addition polymerization initiator; and
III) causing the addition polymerization initiator to form a free radical while continuously introducing to the aqueous colorant mixture a monomer mixture comprising:
a) an addition polymerization initiator, and
b) at least one ethylenically-unsaturated monomer;
thereby forming the composite colorant particles having a colorant phase and a polymer phase.
Another embodiment of the invention relates to the composite colorant particles prepared by the above process.
The composite colorant particles made by the process of the invention have better stability than those prepared by the prior art and an ink formulated with such particles has good resistance to abrasion.
In accordance with the present invention, a portion of an addition polymerization initiator is added to an aqueous colorant mixture before introducing a monomer mixture which is used to form the polymer phase of the composite colorant particles. The aqueous colorant mixture comprises submicron colorant particles which are used to form the colorant phase of the composite particles. The colorant phase and the polymer phase are essentially incompatible. However there may be an interface formed between the colorant phase and polymer phase.
In a preferred embodiment of the invention, the ethylenically-unsaturated monomer which may be employed comprises:
a) an ethylenically-unsaturated monomer being free of ionic charge groups and capable of addition polymerization to form a substantially water-insoluble homopolymer, and
b) another ethylenically-unsaturated monomer being capable of addition polymerization to form a substantially water-soluble homopolymer;
In accordance with the invention, the monomer mixture is added to the colorant mixture continuously. The duration of the addition time depends on the types of monomers and reaction temperatures employed. The addition time can be shorter for more reactive monomers and at higher reaction temperatures. For monomers of low reactivity at a lower reaction temperature, a shorter monomer addition time may flood the system with free monomers which can form secondary polymer particles which comprise essentially no colorant phase. With longer addition time, the polymerization is carried out under monomer starvation conditions and almost all the monomers are consumed by the colorant particles.
In accordance with the invention, a preferred way to cause an addition polymerization initiator to form a free radical is by using heat. Depending on the types of initiators used, the reaction temperature can vary from about 30 to about 90xc2x0 C. Preferably the reaction temperature is at least 40xc2x0 C. and most preferably at least 50xc2x0 C. To ensure that no free monomer is present, usually the reaction is continued for a longer time after the monomer addition. Also monomer may be need to be added to scavenge during the final stage of the reaction to increase the reaction conversion.
A wide variety of organic and inorganic pigments, alone or in combination, may be selected for use in the present invention. Colorant particles which may be used in the invention include pigments as disclosed, for example in U.S. Pat. Nos. 5,026,427; 5,086,698; 5,141,556; 5,160,370; and 5,169,436, the disclosures of which are hereby incorporated by reference. The exact choice of pigments will depend upon the specific application and performance requirements such as color reproduction and image stability. Pigments suitable for use in the present invention include, for example, azo pigments, monoazo pigments, disazo pigments, azo pigment lakes, xcex2-Naphthol pigments, Naphthol AS pigments, benzimidazolone pigments, disazo condensation pigments, metal complex pigments, isoindolinone and isoindoline pigments, polycyclic pigments, phthalocyanine pigments, quinacridone pigments, perylene and perinone pigments, thioindigo pigments, anthrapyrimidone pigments, flavanthrone pigments, anthanthrone pigments, dioxazine pigments, triarylcarbonium pigments, quinophthalone pigments, diketopyrrolo pyrrole pigments, titanium oxide, iron oxide, and carbon black. Typical examples of pigments which may be used include Color Index (C.I.) Pigment Yellow 1, 2, 3, 5, 6, 10, 12, 13, 14, 16, 17, 62, 65, 73, 74, 75, 81, 83, 87, 90, 93, 94, 95, 97, 98, 99, 100, 101, 104, 106, 108, 109, 110, 111, 113, 114, 116, 117, 120, 121, 123, 124, 126, 127, 128, 129, 130, 133, 136, 138, 139, 147, 148, 150, 151, 152, 153, 154, 155, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 183, 184, 185, 187, 188, 190, 191, 192, 193, 194; C.I. Pigment Orange 1, 2, 5, 6, 13, 15, 16, 17, 17:1, 19, 22, 24, 31, 34, 36, 38, 40, 43, 44, 46, 48, 49, 51, 59, 60, 61, 62, 64, 65, 66, 67, 68, 69; C.I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 21, 22, 23, 31, 32, 38, 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 49:3, 50:1, 51, 52:1, 52:2, 53:1, 57:1, 60:1, 63:1, 66, 67, 68, 81, 95, 112, 114, 119, 122, 136, 144, 146, 147, 148, 149, 150, 151, 164, 166, 168, 169, 170, 171, 172, 175, 176, 177, 178, 179, 181, 184, 185, 187, 188, 190, 192, 194, 200, 202, 204, 206, 207, 210, 211, 212, 213, 214, 216, 220, 222, 237, 238, 239, 240, 242, 243, 245, 247, 248, 251, 252, 253, 254, 255, 256, 258, 261, 264; C.I. Pigment Violet 1, 2, 3, 5:1, 13, 19, 23, 25, 27, 29, 31, 32, 37, 39, 42, 44, 50; C.I. Pigment Blue 1, 2, 9, 10, 14, 15:1, 15:2, 15:3, 15:4, 15:6, 15, 16, 18, 19, 24:1, 25, 56, 60, 61, 62, 63, 64, 66; C.I. Pigment Green 1, 2, 4, 7, 8, 10, 36, 45; C.I. Pigment Black 1, 7, 20, 31, 32, and C.I. Pigment Brown 1, 5, 22, 23, 25, 38, 41, 42. In a preferred embodiment of the invention, the pigment set is cyan pigment, C.I. Pigment Blue 15:3; quinacridone magenta, C.I. Pigment Red 122; C.I. Pigment Yellow 155; and carbon black, C.I. Pigment Black 7.
The colorant particles prepared by the process of the present invention can employ water-soluble or water-insoluble dyes. Examples of water-soluble dyes which may be used include the sulfonate and carboxylate dyes, specifically, those that are commonly employed in ink-jet printing. Specific examples include: Sulforhodamine B (sulfonate), Acid Blue 113 (sulfonate), Acid Blue 29 (sulfonate), Acid Red 4 (sulfonate), Rose Bengal (carboxylate), Acid Yellow 17 (sulfonate), Acid Yellow 29 (sulfonate), Acid Yellow 42 (sulfonate), Acridine Yellow G (sulfonate), Nitro Blue Tetrazolium Chloride Monohydrate or Nitro BT, Rhodamine 6G, Rhodamine 123, Rhodamine B, Rhodamine B Isocyanate, Safranine O, Azure B, Azure B Eosinate, Basic Blue 47, Basic Blue 66, Thioflacin T (Basic Yellow 1), and Auramine O (Basic Yellow 2), all available from Aldrich Chemical Company. Examples of water-insoluble dyes which may be used include azo, xanthene, methine, polymethine, and anthroquinone dyes. Specific examples of water-insoluble dyes include Ciba-Geigy Orasol Blue GN, Ciba-Geigy Orasol Pink, and Ciba-Geigy Orasol Yellow.
The composite colorant particles prepared by the process of the invention may have any particle size, such as those which can be jetted through a print head. Preferably, the composite colorant particles have a mean particle size of less than about 200 nm, more preferably less than about 80 nm.
Various processes known in the art can be used in the invention to form a suspension of a colorant particle in an aqueous medium. The suspensions are primarily composed of colorant particles, dispersants/surfactants, and water. The dispersants can be nonionic, anionic, cationic, and/or polymeric and can be used at levels as high as 50% of the colorant particles.
Colorant particles useful in the invention can be formed by various methods known in the art. For example, they can be prepared by pulverizing and classifying dry pigments or by spray drying of a solution containing dyes followed by redipsersing the resultant particles in water using a dispersant. They can be prepared by a suspension technique which includes dissolving a dye in, for example, a water-immiscible solvent, dispersing the solution as fine liquid droplets in an aqueous solution, and removing the solvent by evaporation or other suitable techniques. They can also be prepared by mechanically grinding a pigment material in water to a desired particle size in the presence a dispersant.
Addition polymerization initiators useful in the practice of the invention include, for examples, an azo and diazo compounds, such as 2,2xe2x80x2-azobisisobutyronitrile, 2,2xe2x80x2-azobis(2,4-dimethyl valeronitrile), 2,2xe2x80x2-azobis(2,3-dimethyl butyronitrile), 2,2xe2x80x2-azobis(2-methyl butyronitrile), 2,2xe2x80x2-azobis(2,3,3-trimethyl butyronitrile), 2,2xe2x80x2-azobis(2-isopropyl butyronitrile), 1,1xe2x80x2-azobis(cyclohexane-1-carbonitrile), 2,2xe2x80x2-azobis(4-methoxyl-2,4-dimethyl valeronitrile), 2-(carbamoylazo)isobutyronitrile, 4,4xe2x80x2-azobis(4-cyanovaleric acid), and dimethyl-2,2xe2x80x2azobis isobutyrate, or peroxide compounds, such as butyl peroxide, propyl peroxide, butyryl peroxide, benzoyl isobutyryl peroxide, and benzoyl peroxide, or water soluble initiators, for example, sodium persulfate, and potassium persulfate, or any redox initiators. The initiators may be used in an amount varying from about 0.2 to 3 or 4 weight percent or higher by weight of the total monomers. Usually, a higher initiator concentration results in lower molecular weights of the final polymers. In general, if the colorant is an organic pigment, then good results have been obtained using either an oil-soluble initiator or a water-soluble initiator. If the colorant is an inorganic pigment, such as carbon black, then good results can be obtained using a water-soluble initiator.
Surfactants that can be used in the present invention include, for example, a sulfate, a sulfonate, a cationic compound, a reactive surfactant, an amphoteric compound, and a polymeric protective colloid. Specific examples are described in xe2x80x9cMcCutcheon""s Emulsifiers and Detergents: 1995, North American Editorxe2x80x9d. A chain transfer agent such as butyl mercaptan, may also be used to control the properties of the polymer formed.
The ethylenically-unsaturated monomers which can be used in the invention include, for example, the following monomers and their mixtures: acrylic acid, methacrylic acid, ethacrylic acid, methyl acrylate, ethyl acrylate, ethyl methacrylate, benzyl acrylate, benzyl methacrylate, propyl acrylate, propyl methacrylate, iso-propyl acrylate, iso-propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl methacrylate, octadecyl methacrylate, octadecyl acrylate, lauryl methacrylate, lauryl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxyhexyl acrylate, hydroxyhexyl methacrylate, hydroxyoctadecyl acrylate, hydroxyoctadecyl methacrylate, hydroxylauryl methacrylate, hydroxylauryl acrylate, phenethylacrylate, phenethyl methacrylate, 6-phenylhexyl acrylate, 6-phenylhexyl methacrylate, phenyllauryl acrylate, phenyllaurylmethacrylate, 3-nitrophenyl-6-hexyl methacrylate, 3-nitrophenyl-18-octadecyl acrylate, ethyleneglycol dicyclopentyl ether acrylate, vinyl ethyl ketone, vinyl propyl ketone, vinyl hexyl ketone, vinyl octyl ketone, vinyl butyl ketone, cyclohexyl acrylate,3-methacryloxypropyl-dimethylmethoxysilane,3-methacryloxypropyl-methyldimethoxysilane,3-methacryloxypropyl-pentamethyldisiloxane, 3-methacryloxypropyltris-(trimethylsiloxy)silane,3-acryloxypropyl-dimethylmethoxysilane, acryloxypropylmethyldimethoxysilane, trifluoromethyl styrene, trifluoromethyl acrylate, trifluoromethyl methacrylate, tetrafluoropropyl acrylate, tetrafluoropropyl methacrylate, heptafluorobutyl methacrylate, isobutyl acrylate, isobutyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isooctyl acrylate, isooctyl methacrylate, N,N-dihexyl acrylamide, N,N-dioctyl acrylamide, N,N-dimethylaminoethyl acrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl acrylate, N,N-diethylaminoethyl methacrylate, piperidino-N-ethyl acrylate, vinyl propionate, vinyl acetate, vinyl butyrate, vinyl butyl ether, and vinyl propyl ether ethylene, styrene, vinyl carbazole, vinyl naphthalene, vinyl anthracene, vinyl pyrene, methyl methacrylate, methyl acrylate, alpha-methylstyrene, dimethylstyrene, methylstyrene, vinylbiphenyl, glycidyl acrylate, glycidyl methacrylate, glycidyl propylene, 2-methyl-2-vinyl oxirane, vinyl pyridine, aminoethyl methacrylate, aminoethylphenyl acrylate, maleimide, N-phenyl maleimide, N-hexyl maleimide, N-vinyl-phthalimide, and N-vinyl maleimide poly(ethylene glycol) methyl ether acrylate, polyvinyl alcohol, vinyl pyrrolidone, vinyl 4-methylpyrrolidone, vinyl 4-phenylpyrrolidone, vinyl imidazole, vinyl 4-methylimidazole, vinyl 4-phenylimidazole, acrylamide, methacrylamide, N,N-dimethyl acrylamide, N-methyl acrylamide, N-methyl methacrylamide, aryloxy dimethyl acrylamide, N-methyl acrylamide, N-methyl methacrylamide, aryloxy piperidine, and N,N-dimethyl acrylamide acrylic acid, methacrylic acid, chloromethacrylic acid, maleic acid, allylamine, N,N-diethylallylamine, vinyl sulfonamide, sodium acrylate, sodium methacrylate, ammonium acrylate, ammonium methacrylate, acrylamidopropanetriethylammonium chloride, methacrylamidopropane-triethylammonium chloride, vinyl-pyridine hydrochloride, sodium vinyl phosphonate and sodium 1-methylvinylphosphonate, sodium vinyl sulfonate, sodium 1-methylvinyl-sulfonate, sodium styrenesulfonate, sodium acrylamidopropanesulfonate, sodium methacrylamidopropanesulfonate, and sodium vinyl morpholine sulfonate, allyl methacrylate, allyl acrylate, butenyl acrylate, undecenyl acrylate, undecenyl methacrylate, vinyl acrylate, and vinyl methacrylate; dienes such as butadiene and isoprene; esters of saturated glycols or diols with unsaturated monocarboxylic acids, such as, ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,3-butanediol dimethacrylate, pentaerythritol tetraacrylate, trimethylol propane trimethacrylate and polyfunctuional aromatic compounds such as divinylbenzene and the like.
As was noted above, the term xe2x80x9ccompositexe2x80x9d means that the colorant particles prepared by the process of the invention comprise at least two physical phases. The phase domains are not separated apart from each other and there are bonds or interfaces between them.
A way in which the composite particles of the invention can be distinguished from a physical mixture of colorant particles and polymer particles is by their dispersion stability in a water-miscible organic solvent. A physical mixture of the two separate particles are not stable in, for example, acetone or tetrahydrofuran (THF). However, the composite colorant particles prepared by the process of the invention are stable for a long period of time in acetone or THF.
While the composite colorant particles prepared by the process of the invention described herein are illustrated for use in ink jet inks, they may also have other applications such as, e.g., in paints, inks for writing pens, markers, cosmetic products, etc.
In forming an ink jet ink, it is desirable to make the composite colorant particles in the form of a concentrate. The concentrate is then diluted with an appropriate solvent to a concentration best for viscosity, color, hue, saturation density, and print area coverage for the particular application. Acceptable viscosities for such inks, as determined using a Brookfield apparatus and related methods, are generally not greater than 20 centipoise, and are preferably in the range of about 1 to 15 centipoise.
The composite colorant particles prepared by the process of the invention can comprise up to about 30% by weight of an ink jet ink composition, and preferably from about 0.05 to 15 wt. %. Co-solvents or a humectant can also be added to the ink composition to help prevent the ink from drying out or crusting in the orifices of the printhead. Classes of co-solvents and humectants which may be employed include, but are not limited to, monohydric alcohols with carbon chains greater than about 10 carbon atoms such as decanol, dodecanol, oleoyl alcohol, stearoyl alcohol, hexadecanol, eicosanol, polyhydric alcohols, such as ethylene glycol, alcohol, diethylene glycol(DEG), triethylene glycol, propylene glycol, tetraethylene glycol, polyethylene glycol, glycerol, 2-methyl-2,4-pentanediol, 2-ethyl-2-hydroxymethyl-1,3-propanediol(EHMP), 1,5 pentanediol, 1,2-hexanediol, 1,2,6-hexanetriol and thioglycol; lower alkyl mono- or di-ethers derived from alkylene glycols, such as ethylene glycol mono-methyl or mono-ethyl ether, diethylene glycol mono-methyl or mono-ethyl ether, propylene glycol mono-methyl or mono-ethyl ether, triethylene glycol mono-methyl or mono-ethyl ether, diethylene glycol di-methyl or di-ethyl ether, poly(ethylene glycol) monobutyl ether (PEGMBE), and diethylene glycol monobutylether(DEGMBE), nitrogen-containing compounds, such as urea, 2-pyrrolidinone, N-methyl-2-pyrrolidinone, and 1,3-dimethyl-2-imidazolidinone; and sulfur-containing compounds such as dimethyl sulfoxide and tetramethylene sulfone.
In an inkjet ink, the polymer phase composition can be selected to maximize the compatibility of the composite particles with the organic solvent used in the formulation, and to maximize the interaction with the substrate where the ink is applied. The maximized compatibility with the organic solvent produces long term storage stability, and the maximized interaction with the substrate improves the adhesion or smudge resistance of the image area.
A biocide may be added to an ink jet ink composition to suppress the growth of micro-organisms such as molds, fungi, etc. in aqueous inks. A preferred biocide for an ink composition is Proxel(copyright) GXL (Zeneca Specialties Co.) at a final concentration of 0.0001-0.5 wt. %. Additional additives which may optionally be present in an ink jet ink composition include thickeners, conductivity enhancing agents, anti-kogation agents, drying agents, waterfast agents, dye solubilizers, chelating agents, binders, light stabilizers, viscosifiers, buffering agents, anti-mold agents, anti-curl agents, stabilizers and defoamers.
Inkjet inks made using composite colorant particles prepared by the process of this invention are employed in ink jet printing wherein liquid ink drops are applied in a controlled fashion to an ink receptive substrate, by ejecting ink droplets from plurality of nozzles, or orifices, in a print head of ink jet printers.
Commercially available ink jet printers use several different methods to control the deposition of the ink droplets. Such methods are generally of two types: continuous stream and drop-on-demand.
In drop-on-demand systems, a droplet of ink is ejected from an orifice directly to a position on the ink receptive layer by pressure created by, for example, a piezoelectric device, an acoustic device, or a thermal process controlled in accordance digital data signals. An ink droplet is not generated and ejected through the orifices of the print head unless it is needed. Ink jet printing methods, and related printers, are commercially available and need not be described in detail.
Ink jet inks using composite colorant particles prepared by the process of this invention can be employed in ink jet printing wherein liquid ink drops are applied in a controlled fashion to an ink receptive layer substrate, by ejecting ink droplets from the plurality of nozzles, or orifices, in a print head of ink jet printers.
Ink-receptive substrates useful in ink jet printing are well known to those skilled in the art. Representative examples of such substrates are disclosed in U.S. Pat. Nos. 5,605,750; 5,723,211; and 5,789,070 and EP 813 978 A1, the disclosures of which are hereby incorporated by reference.
The following examples illustrate the utility of the present invention.

Process for making composite colorant particles

Abstract: III) causing the addition polymerization initiator to form a free radical while continuously introducing continuously to the aqueous colorant mixture a monomer mixture comprising:


A sorption cooler for cooling substances in a vessel (4) by means of a sorption agent (11) within a sorption agent vessel (10), which in connected via a vapor valve (9) to an evaporator (10) for generation of working agent vapor, and where a part of the outer wall (1) of the vessel (4) is in good thermal contact with a working agent storage material (2) and at least this part of the outer wall (1) of vessel (4) is at the same time a part of the boundary surface (5) of the evaporator (8).

The invention concerns a sorption cooler for cooling a container by means of a sorption device and a method for regeneration of the sorption agent in accordance with the generic term of claim 1.
Sorption devices are devices in which a liquid or solid sorption agent adsorbs a second, higher boiling agent, the working agent, in vapor form with release of heat (sorption). The working agent is evaporated in an evaporator while taking up heat. After the sorption agent is saturated, it can be desorbed through the delivery of heat (regeneration). In doing so, the working agent is evaporated out of the sorption agent. The work agent vapor can be reliquefied and then reevaporated in the evaporator.
Sorption devices for cooling with solid sorption agents are known from EP 0 368 111 and DE-OS 34 25 419. Sorption agent vessels filled with sorption agents draw off the working agent vapor, which arises in an evaporator, and adsorb it in the sorption agent fill while releasing heat. The heat of adsorption in this case must be withdrawn from the sorption agent fill. The cooling devices can be used for cooling and keeping foods warm in thermally insulated boxes.
The sorption cooling system known from EP 9 368 111 consists of a portable cooling unit and a stationary charging station that can be separated from it. The cooling unit consists of a sorption vessel filled with a solid sorbent and an evaporator, which contains the liquid working agent and a heat exchanger embedded therein. The evaporator and sorption vessel are connected to each other via a closeable vapor pipe. Liquid media that are cooled to the desired temperature level through temperature-controlled opening and closing of the closing device flow through a heat exchanger embedded in the evaporator. After the sorption agent has become saturated with the working agent, it can be heated in the charging station. The working agent vapor that flows out is reliquefied in the evaporator. The heat of condensation is withdrawn through cooling water, which must flow through the embedded heat exchanger.
Because of the embedded heat exchanger and temperature regulation, the sorption cooling system is expensive to manufacture and is complicated in its practical use for the untrained layman.
The task of the invention is to show an operation that is simpler than the prior art and a low-cost device.
This task is solved by the characteristic traits of claims 1 and 10. The dependent claims show additional inventive devices.
Accordingly, a sorption device in accordance with the invention contains a sorption agent within a sorption agent vessel, a vapor valve and a liquid working agent distributed in a working agent storage material within an evaporator. A portion of the outer wall of the container is in good thermal contact with the working agent storage material and at least this part of the outer wall of the container is at the same time apart of the boundary surface s of the evaporator.
The working agent storage material contains, for example, nonwoven glass fiber or mineral fiber materials and is glued or stretched over a large area. In the case of cylindrical vessels it is, as a rule, sufficient to coat the outer side surface of the container. Coating of the more highly vaulted bottom and top elements is not necessary. The shape of the vessel does not have to be adjusted to the special requirements of sorption technology. The working agent is evaporated out of the working agent storage material and cools the contents of the vessel through the good contact with the vessel wall.
In accordance with the invention another part of the boundary surface of the evaporator has thermal contact with the environment. In this region the working agent vapor can condense and give up its heat of condensation to the environment or to an external cooling medium. This will always take place when the environment or the external cooling medium is colder than the contents of the vessel. The working medium then evaporates from the working medium storage material while absorbing heat and condenses while giving up heat to the environment. Through this effect, which is also known as a heat pipe, the contents of the vessel are constantly reduced to the environmental temperature. However, if the environment is warmer than the contents of the vessel, no heat can be transferred from outside to the inside, provided the boundary surface in contact with the environment is free of liquid working agent. In order to guarantee this, the boundary surface is inclined so that the condensate runs off and can drip back onto the working medium storage material. This heat pipe effect is always of particular advantage when the vessel contents are supposed to take on the lower temperature automatically through a decrease of the ambient temperature. If, for example, the sorption cooler is installed in a cooling chamber, the temperature of the vessel contents will fall to the lower level; conversely, if the outside temperature rises, for example due to solar radiation, the construction of the sorption cooler in accordance with the invention acts like an insulated vessel under a vacuum. In doing so, the rise of the vessel temperature progresses a great deal more slowly than the decrease does.
Even during the regeneration phase, in which the sorption agent is desorbed from the working agent, the working agent vapor can condense on the boundary surface of the evaporator that is in contact with the environment. This always occurs when the boundary surface is colder than the vessel contents.
It is also advantageous if another wall region of the evaporator is at the same time a component of the sorption agent vessel. Weight and costs can be saved through the consolidation of the intermediate walls that is then possible. This is particularly true when the vapor valve is arranged in a common wall. Additional flow channels and connecting elements can then be spared.
Particularly compact and stable embodiments of the idea in accordance with the invention are achieved when the sorption cooler has a shell-like structure. In this case, a cylindrical evaporation jacket is arranged around the cylindrical vessel and around this jacket in turn is the cylindrical sorption vessel, which uses the evaporation jacket simultaneously as its inside wall. In order to reduce the thermal contact between the sorption agent and the evaporator, thermal insulation agents can be arranged within the sorption agent vessel.
However, this additional insulation can be avoided if the working agent vapor pressure is especially low. In the case of low vapor pressures the conductive and convective fractions of heat transfer are reduced. If the zeolite/water pair is used, the achievable insulation effect lies in the range of simple vacuum insulation. The radiant fraction that is still relevant in this case can be further reduced by building in radiation shields. It is particularly advantageous if the common intermediate wall between evaporator and the sorption agent vessel acts as a radiation shield.
During the regeneration phase the sorption agent is heated and the working agent vapor is desorbed. The vapor flows through the vapor valve to the evaporator and condenses out there. At the end of the regeneration, the input of heat to the sorption agent is interrupted. The desorption of additional working agent vapor ends with this. The vapor valve is closed. The desorbed working agent is in liquid state in the working agent-storage material. The sorption agent is cooled afterwards to the ambient temperature by the release of heat through the outer wall of the sorption agent vessel.
To initiate the cooling phase, the vapor valve is opened. The working agent vapor can now flow from the evaporator into the sorption agent vessel and be exothermically sorbed by the sorption agent. The evaporating working agent is cooled in the evaporator and cools the vessel together with its contents. In order to produce the maximum cooling power, the sorption agent must be able to give up its heat of sorption. A particularly intensive cooling effect is achieved if the sorption agent vessel has a sufficiently large surface for heat exchange to the air that surrounds it. Advantageously, the vessel wall should be cooled to temperatures under 50xc2x0 C. Then sufficiently low temperatures are possible in the evaporator.
If the vessel contains liquids, only the liquid volume that is around and below the working agent-storage material has to be cooled. The volume that is higher up remains near the starting temperature because of the lower density and low thermal conduction of the liquids. By appropriate positioning and arrangement of the evaporator the liquid volume to be cooled can be selected beforehand. In practice one achieves in this way a faster cooling of the liquid at the bottom, which is then withdrawn first. The liquid at the top is not cooled until it falls into the region of the evaporator through the removal of the chilled amount of liquid.
Before refilling a vessel, it is usually cleaned. For this, cleaning and rinse washing liquids are introduced into the vessel and as a rule removed by tipping the vessel. For this reason the evaporator is designed so that the vessel can empty in all cleaning processes without any problems and without traces of rinse agent.
The use of the sorption agent pair zeolite/water is particularly advantageous. Zeolite is a crystalline mineral that consists of a regular framework structure of silicon and aluminum oxides. This framework structure contains voids in which water molecules can be sorbed while releasing heat. Within the framework structure the water molecules are subject to strong field forces that liquefy the molecules in the lattice and bind them in a liquid-like phase. The strength of the binding forces acting on the water molecules is dependent on the amount of water already contained in the framework structure and the temperature of the zeolite. For practical use up to 25 grams of water can be sorbed per 100 grams of zeolite. The amount of cold that can be generated in the evaporation here is sufficient to cool about 1 liter of water by about 14 kelvin. Zeolites are solid substances without problematic heat expansion in the sorption or desorption reaction. The framework structure is freely accessible to water vapor molecules on all sides. The devices are thus capable of use in any position.
The use of water as working agent allows the costs required for control to be reduced to a minimum. In the evaporation of water under a vacuum the water surface cools to 0xc2x0 C. and freezes to ice with continuous evaporation. This ice layer rapidly grows until the resulting pressure drop through the ice layer reduces the growth. The ice layer can be used advantageously to control the liquid temperature. With low delivery of heat from the vessel the ice layer grows, while with much higher delivery it melts. Through the natural ice formation the heat transfer from the liquid into the evaporator is reduced so that the liquid does not cool under 0xc2x0 C. and as a rule remains at 4 to 5xc2x0 C.
It is also possible to add substances that lower the freezing point to the aqueous working agent if the outlet temperature of the liquid is to be reduced to below 4xc2x0 C.
However, it is also possible to use other sorption agent pairs with which the sorption agent is solid and remains solid even during the sorption reaction. Solid sorption agents have low thermal conduction and poor heat transfer. Since even the heat transfer from gaseous media (air, waste gases) to the sorption agent vessel lies in the same order of magnitude, in principle heat exchangers without fins are recommended, for example cylindrical or tube geometries.
Some solid sorption agents like zeolites are stable enough even to compensate external excess pressures on thin-walled vessel walls. Additional stiffening or thick-walled heat exchanger surfaces are for this reason not necessary. Since the sorption apparatus is under a vacuum when water is used as the working agent and no gases should get into the system for the entire life span of the system, vacuum tight components are to be preferred for the vapor valve. For manual operation feed-through devices that are sealed by means of metal bellows have proven themselves.
In accordance with the invention the vapor valve is operated by a lever device, one end of which is linked to the evaporator or sorption vessel outer wall and the other end of which operates the valve. By deforming the outer wall at the point of the first lever end the valve device can be operated in accordance with the invention without expensive vacuum feed-through devices.
Sorption agent temperatures from 250 to 350xc2x0 C. in regeneration and 40 to 80xc2x0 C. in sorption are recommended for an economical mode of operation. Since zeolite granulates in particular have low thermal conduction, the sorption vessel should be designed so that the heat conduction path for the converted amounts of heat does not exceed 18 mm. All of the known devices that achieve the necessary temperature level and do not unnecessarily heat the contents of the vessel are suitable as heat sources for regeneration. Electrically heated plates or jackets that are matched to the geometry of the sorption agent vessel are advantageous. The heating can be arranged on a palette, for example for several sorption coolers, in order to make use of production-related wait times after filling the vessels for regeneration. Also advantageous are heating devices that heat the sorption agent fill via radiant or inductive heat (eddy currents). Of course, it is also possible to connect the heating device permlanently to the sorption vessel and even to leave it there in the transportation of mobile sorption coolers.
Regeneration in a hot air oven at an air temperature over 300xc2x0 C. is particularly advantageous. If the zeolite fill is arranged in a thin layer on the inner side of the outer jacket, the regeneration can be completed within an hour. In regeneration in a hot air oven, the vacuum insulation protects the liquid against undesired heating.
During the cooling phase, the surface of the sorption agent vessel can heat up to temperatures over 100xc2x0 C. For this case suitable measures to protect against combustion are to be provided. Surface coatings of paper and fiber materials that protect against burning even at higher temperatures have proven themselves. If these coatings are wetted, a greater cooling power on the vessel is simultaneously possible through the evaporative cooling that occurs at the same time.
Narrow-mesh surface protective nets that prevent contact with the hot sorption vessel wall are also advantageous. Protective nets and plastic shrink films also optimally fit bulgy surface shapes and at the same time offer protection against mechanical damage.
No particular requirements are imposed on the size and geometry of the vessel. Thus all of the vessel that are conventional today for flowable contents (for example barrels, transport boxes, cans, open vessels, film sacks, multi-layer packagings, plastic vessels, canisters, hobbocks, bottles, pots, etc.) are suitable, provided they can be functionally connected to the sorption apparatus. High (tall) geometries with small diameters are preferred over flat shapes with large diameters, since the former enable faster cooling of the contents.


The invention relates to a cosmetic composition for protecting the skin against ultraviolet radiation of wavelengths between 280 and 400 nm, comprising, in a cosmetic vehicle containing at least one fatty phase, an effective amount of copper (II) bis(3,5-diisopropylsalicylate).

The present invention relates to the use of a cupric complex of 3,5-diisopropylsalicylic acid by way of a cosmetic product, to a cosmetic composition containing the said complex and to a process for protecting the human epidermis against ultraviolet radiation using the said cosmetic composition.
It is well-known that, when subjected to solar irradiation, the skin undergoes various modifications and, in particular, certain injuries.
Among the injuries caused to the skin by the sun, the most dramatic is unquestionably sunburn or solar erythema, which appears, depending on the intensity and duration of irradiation, between the second and the twenty fourth hour after exposure to the sun. Solar erythema may manifest itself by a slight pink coloration of the skin, but can also lead to genuine burns accompanied by considerable disorders of the general condition.
Solar radiation can also cause cellular modifications in the skin. The formation in the epidermis of keratinocytes that are degraded or even destroyed by UV radiation is observed in particular, these being degenerate cells which are necrosed through the action of solar radiation, generally known by the name of xe2x80x9csunburn cellsxe2x80x9d.
The region of solar radiation responsible for these phenomena falls within the ultraviolet radiation, that is to say in the range of wavelengths between 280 and 400 nm. An effort has hence been made to protect the skin by applying substances possessing an absorption maximum in this region. These substances constitute what are known as sunscreens. Depending on the quantity of sunscreen applied on the skin, a larger or smaller portion of the damaging rays is stopped, thereby proportionately decreasing the appearance of the injuries caused to the skin.
Many sunscreens have already been recommended, having a diversity of chemical natures and possessing a variety of physicochemical properties, especially as regards solubility (water-soluble or fat-soluble products). These compounds provide what may be referred to as a primary protection.
However, the absorption of the ultraviolet radiation by the screens is never complete. There hence remains a residual amount of energy-rich radiation which reaches the skin. Thus, sunscreens lessen the injuries created in the skin without completely abolishing them.
It is hence desirable to combine the sunscreens with, or replace them by, products capable of decreasing the injuries caused to the skin by a phenomenon other than simple screening.
The Applicant has discovered that the application on the skin of a complex composed of two molecules of 3,5-diisopropylsalicylic acid and one atom of copper, namely copper (II) bis(3,5-diisopropylsalicylate), of formula
surprisingly enabled the intensity of the solar erythema and the number of degraded keratinocytes to be reduced, without these properties being due to a distinct absorbing power in the ultraviolet radiation region. These properties persist in the presence of sunscreens.
The cupric complex of 3,5-diisopropylsalicylic acid is a known compound whose synthesis is described in xe2x80x9cJournal of Medicinal Chemistryxe2x80x9d, 1976, Vol. 19, No. 1, p. 135-148. This document, and also U.S. Pat. No. 4,221,785, also describe the anti-inflammatory and anti-ulcer properties of this cupric complex, which can be administered parenterally, especially subcutaneously, and orally. International Patent Application WO 84/04,922 describes this compound as an intramuscularly administered anti-tumour agent.
However, the topical application of this cupric complex in the cosmetics field, which forms the subject of the present invention, is not recommended in any of these documents of the prior art cited above. In point of fact, the Applicant has been able to demonstrate that the action of this cupric complex with respect to UV radiation is exerted chiefly at the skin surface.
The subject of the present invention is hence the use of copper (II) bis(3,5-diisopropylsalicylate) by way of a cosmetic product.
The subject of the present invention is also a cosmetic composition which is useful for protecting the skin against ultraviolet radiation of wavelengths between 280 and 400 nm comprising, in a cosmetically acceptable vehicle containing at least one fatty phase, an effective amount of copper (II) bis(3,5-diisopropylsalicylate).
Another subject of the invention consists of a cosmetic composition for protecting the skin comprising, in a cosmetically acceptable vehicle containing at least one fatty phase, the said cupric complex of 3,5-diisopropylsalicylic acid and at least one sunscreen which absorbs ultraviolet rays of wavelengths between 280 and 400 nm.
The present invention also relates to a process for protecting the skin against injuries caused by UV radiation, consisting in maintaining on the skin during the irradiation an effective amount of a cosmetic composition comprising the abovementioned cupric complex of 3,5-diisopropylsalicylic acid.
Other subjects and characteristics of the invention will become apparent on reading the description which follows.
The cosmetic composition according to the invention contains, in a fatty phase, the cupric complex of 3,5-diisopropylsalicylic acid in a concentration range extending from 0.01 to 5%, and preferably from 0.05 to 1%, by weight based on the total weight of the composition. It should be noted that the above cupric complex, although coloured in solution, does not colour the skin at the concentrations used.
As a result of the fat-soluble nature of the cupric complex used, the cosmetic compositions according to the invention contain at least one fatty phase. They can take the form of oils, oleo-alcoholic lotions, emulsions such as creams or milks, fatty or oleo-alcoholic gels, or solid sticks, or can be packaged as an aerosol.
The fatty phase consists of fats such as mineral, animal or vegetable oils or waxes, fatty acids, fatty acid triglycerides having from 6 to 18 carbon atoms and fatty alcohols.
In addition to the fatty phase, the cosmetic vehicle can also contain lower monohydric alcohols or polyhydric alcohols containing from 1 to 6 carbon atoms, or alternatively water and mixtures of these different constituents.
The mono- or polyhydric alcohols which are more especially preferred are chosen from ethanol, isopropanol, propylene glycol, glycerol and sorbitol. The aqueous-alcoholic mixtures are preferably mixtures of water and ethanol.
By way of fats, the following may be used:
mineral oils such as liquid paraffin;
animal oils such as whale, seal, menhaden, halibut-liver, cod, tuna, tortoise, tallow, neat""s-foot, horse""s-foot, sheep""s-foot, mink, otter and marmot oils;
vegetable oils such as almond, groundnut, wheat-germ olive, maize-germ, jojoba, sesame, sunflower, palm, walnut and rapeseed oils.
It is also possible to use the following as fats: vaseline, paraffin, hydrogenated lanolin, acetylated lanolin and silicone oils.
As waxes, it is possible to use sipol wax, lanolin wax, beeswax, candelilla wax, microcrystalline wax, carnauba wax, spermaceti, cocoa butter, shea butter, silicone waxes, hydrogenated oils which are solid at 25xc2x0 C., sucro-glycerides, and Ca, Mg, Zn and Al oleates, myristates, linoleates and stearates.
Among fatty alcohols, lauryl, cetyl, myrystyl, stearyl, palmityl and oleyl alcohols may be mentioned.
The cosmetic composition according to the invention can also contain nonionic, anionic, cationic or amphoteric emulsifiers.
It can also be advantageous to use thickeners such as cellulose derivatives, polyacrylic acid derivatives, guar or carob gums or xanthan gums.
The cosmetic composition according to the invention can also contain adjuvants customarily used in cosmetics and in particular moisturizing products, emollients, preservatives, dyestuffs, opacifiers, perfumes and propellants; the propellants are traditional propellants such as alkanes, fluoroalkanes and chlorofluoroalkanes.
The cosmetic composition according to the invention possesses a pH of between 4 and 9, and preferably between 5.5 and 8, which can optionally be adjusted using a pH-regulating agent.
The cosmetic composition according to the invention can also contain, in combination with the cupric complex of 3,5-diisopropylsalicylic acid, at least one sunscreen which absorbs radiation of wavelengths between 280 and 400 nm.
The total concentration of sunscreen(s) is between 0.5 and 20% of the total weight of the composition.
These sunscreens are chosen from derivatives of:
p-aminobenzoic acid;
cinnamic acid;
benzylidenecamphor;
salicylic acid;
anthranilic acid;
urocanic acid;
benzophenone;
dibenzoylmethane;
benzotriazole;
benzimidazolesulphonic acid.
They are chosen, in particular, from those mentioned in the article: xe2x80x9cUV absorbers in sun cosmetics 1978xe2x80x9d, D.H. LIEM and L.T.H. HILlDERINK, International Journal of Cosmetic Science 1, 341-361 (1979).
It is also possible to use screening polymers such as those described in the Applicant""s French Patents 2,237,912 and 2,359,857.
One embodiment of the invention is an emulsion in the form of a cream or milk comprising, in addition to the cupric complex, fatty alcohols, fatty acid esters and, in particular, fatty acid triglycerides, fatty acids, lanolin, natural or synthetic oils or waxes, and emulsifiers, in the presence of water.
Another embodiment of the cosmetic composition of the invention consists of oils based on natural or synthetic oils and waxes, lanolin and fatty acid esters, in particular fatty acid triglycerides, or of oleo-alcoholic lotions based on oils, waxes, fatty acid esters such as fatty acid triglycerides and lower alcohols such as ethanol or glycols such as propylene glycol or polyols such as glycerol.
The cosmetic composition of the invention can also be a fatty gel comprising oils or waxes and a thickener such as silica; the oleo-alcoholic gels comprise, in addition one or more lower alcohols or polyols such as ethanol, propylene glycol or glycerol.
The solid sticks consist of natural or synthetic waxes and oils, fatty alcohols, fatty acid esters, lanolin and other fats.

Use of cupric complex of 3,5-disopropylsalicylic acid by way of a cosmetic product and cosmetic compositions containing this compound for protecting the human epidermis against UV radiation

Abstract: The composition can contain, in addition, one or more UV-B and/or UV/A sunscreens.