This invention provides a selectively permeable protective covering capable of transmitting high quantities of water vapor while also being capable of significantly restricting the passage of noxious or harmful chemicals even under conditions of high humidification. The material of this invention provides the basis for creating protective garments and accessories suitable for application in the broad range of conditions likely to be encountered in realistic use scenarios. In its broadest aspect, the protective and water vapor permeable covering of this invention comprises a sheet of a polyamine polymer wherein at least 10% of the polyamine polymer amines are amine-acid moieties wherein the acidic species of said amine-acid moieties have a pKa less than 6.4.

This invention relates to chemical protective coverings. More specifically, the invention relates to materials and articles that can be used to afford protection of persons or contents from noxious or harmful chemicals in the form of vapors, aerosols, or particulates. The chemical protective coverings provided in accordance with the invention are particularly suitable for applications such as articles of clothing, tents, sleeping bags, and the like.
Chemical protective coverings are intended to prevent harmful levels of chemicals existing in an external environment from reaching the user or wearer or contents of said materials.
Chemical protective clothing is worn when the surrounding environment may present a potential hazard of exposing an individual to harmful or noxious chemicals. Historically the materials used in protective clothing have had to trade off protection for comfort. That is, those offering more protection were unacceptably uncomfortable, and those being of satisfactory comfort did not offer acceptable protection.
For example, one approach which is known in the art, is to interpose what is generally referred to as an xe2x80x9cimpermeablexe2x80x9d material between the wearer and the hazardous environment. A suitable material of this type will exhibit low permeability to harmful chemicals and yet be pliable enough to be employed in a garment or other article of clothing application. An example of this approach would be a glove utilizing butyl rubber as the barrier to harmful chemicals.
Although such materials may provide adequate protection from harmful chemicals by significantly restricting the passage of such agents, these materials also characteristically prevent the passage of water vapor. A material that to a great extent prevents the transmission of water vapor is termed non-breathable.
When used as protective coverings for people, non-breathable materials retard the human body""s process of heat dissipation normally achieved through the evaporation of perspiration. Without significant transmission of water vapor, or breathability, prolonged use-of-such materials can result in intolerable discomfort and even death of the wearer. The discomfort will initially result from high levels of moisture generated by the wearer building up within the protective covering, followed by the heat stresses imposed upon the wearer due to the lack of evaporative cooling. This can progress to heat stroke, and eventually death. Thus, these types of materials may offer satisfactory protection, but unsatisfactory comfort. This problematic characteristic of non-breathable protective covering materials makes them unsuitable for anything more than very short duration usage or limited areas of coverage.
Conversely, many covering materials that possess significant water vapor transmission rates, for instance many woven textiles or nonwoven polyolefin materials, will not provide desired levels of protection to harmful or noxious chemicals. That is, these types of materials may offer satisfactory comfort, but unsatisfactory protection.
Various efforts have been made to address in more favorable terms the trade-off between protection and comfort.
One such effort, well known in the art, involves the use of adsorptive materials which are interposed between the wearer and the contaminated environment such as described in U.S. Pat. No. 4,510,193 by Blucher, Blucher, and de Ruiter.
Adsorptive chemical protective systems work by adsorbing hazardous liquids and vapors into sorbants, thus inhibiting them from reaching that which the systems are intended to protect. One limiting characteristic of sorbants is that they possess a finite capacity to adsorb chemicals. A second limiting characteristic of sorbants is that they will indiscriminately adsorb chemical species for which protection is unnecessary, thus reducing the available capacity for adsorption of the chemicals to which they were intended to provide protection.
The finite capacity and indiscriminate adsorption characteristics of adsorptive systems limit their duration of use and storage life. Adsorptive systems will begin to adsorb various chemical vapor contaminants present in the atmosphere upon exposure, thus progressively reducing their available capacity over time. This limits their duration of use. This process can even occur when the adsorptive systems are kept within sealed packages over long spans of time. This limits the storage life of such materials.
Additionally, the finite capacity and indiscriminate adsorption characteristics necessitate the incorporation of relatively large quantities of sorptive elements within a chemical protective covering in order to achieve and sustain adequate levels of protection. This can result in thick and heavy barrier systems that can have high resistances to heat and moisture transfer and can impose undesirable physiological stresses on the wearer. Thus, adsorptive systems are also restricted by a trade-off between protection and comfort.
Furthermore, increased bulk and weight are also undesired characteristics for the packaging, storage, handling, and transportation of these materials.
A more preferred approach to creating chemical protective coverings that provide satisfactory comfort and protection relies on the use of selectively permeable materials. Materials that are selectively permeable exhibit a significant preferential permeability to specific chemical species. This approach can allow the creation of protective coverings that facilitate the transmission of desired chemical species while restricting the passage of undesired chemical species. Particularly for articles of chemical protective clothing, it would be desirable for a selectively permeable material to have preferential permeability towards water vapor relative to noxious or harmful vapors. That is, the permeability to water vapor is to be substantially greater than the permeability to noxious or harmful vapors. This can provide the basis for protective coverings that will be comfortable while at the same time being highly protective.
As the protective function of selectively permeable materials is not dependent upon sorption of chemicals, they are not bound by the limitations intrinsic to adsorptive systems. Unlike adsorptive systems, which rely upon a significant mass and thickness of appropriate materials to provide adequate and sustained protection, selectively permeable materials, free of these limitations, can be made extremely thin and lightweight. This facilitates the creation of much less bulky and lighter protective garments and accessories.
Regardless of the type of protective covering material employed, it is likely to be exposed in use to differing and frequently varying conditions of humidity and temperature. For example, a wearer of a protective article of clothing will generate varying amounts of heat and moisture internal to the protective covering depending upon the physiological stresses imposed upon the wearer. External to the protective covering, the conditions will vary due to natural motivations such as weather conditions, or human influenced conditions such as could be found within a vehicle or man-made structure. Thus, it is to be expected that a protective covering will be exposed to a wide range of conditions during its use, which must be considered in the design and application of any protective covering material.
These conditions can influence the performance of selectively permeable materials. Selectively permeable materials that possess the desirable quality of high water vapor transmission are generally hydrophilic polymers. As such, their moisture content will be influenced by the relative humidity of their surroundings. As the surrounding relative humidity of such a selectively permeable material changes, the moisture level within the selectively permeable material will also change. In general, it is observed that these materials are more permeable to many chemical vapors at high relative humidity, and conversely are less permeable to many chemical vapors at low relative humidity. Thus, when such materials are employed in chemical protective covering applications, it is important to consider the protective characteristics of these materials over the range of relative humidities which are to be expected during use. Particularly, it is important to consider the permeation of noxious or harmful chemicals under conditions of high humidification. High resistance to the permeation of chemical vapors at conditions of mild relative humidity may not be representative of performance at elevated conditions of relative humidity.
For the applications under consideration, it would be desirable to reduce the permeability to noxious or harmful chemical vapors, particularly at high relative humidity, without an undesirable reduction in the permeation of water vapor. Similarly, it would be desirable to increase the permeation of water vapor, without an undesirable increase in the permeability to noxious or harmful chemical vapors, particularly at high relative humidity.
Thus, to be most useful in protective coverings, selectively permeable materials must provide good breathability and must provide low permeability to hazardous chemicals, particularly at the difficult condition of high relative humidity. Additionally, it is desirable to improve the breathability of such materials without significantly diminishing their protective performance, and to improve their protective performance without significantly diminishing their breathability.
A number of selectively permeable materials have been investigated for general use in these applications. These include a variety of films using cellulose-based polymers such as described in U.S. Pat. No. 5,743,775 by Ulrich Baurmeister and assigned to Akzo Nobel NV as well as porous polyamide films as detailed in U.S. Pat. No. 5,824,405 by Lloyd Steven White and assigned to W.R. Grace and Co. It has also been taught that good breathability and good resistance to hazardous chemicals can be achieved under some conditions using a polyalkyleneimine protective material as described in U.S. Pat. No. 5,391,426 by Huey S. Wu. However, the chemical permeation characteristics of each of these materials are evaluated under relatively low relative humidities that do not represent the range of conditions that would be encountered in use. The performance of these materials will be limited by their compromise between protection and comfort, particularly at elevated relative humidity.
Surprisingly, as taught herein, it has been discovered that the performance of a selectively permeable chemical protective covering based upon a polyamine polymer can be considerably and unexpectedly enhanced by incorporating amine-acid moieties within the polyamine polymer. Unexpectedly, it has been discovered that the water vapor transmission rate may be made substantially better without a comparable trade-off in protective qualities, particularly at elevated relative humidity. Further, it has been discovered that the resistance to noxious or harmful chemicals, particularly at conditions of elevated relative humidity, may be made substantially better without a comparable trade-off in water vapor transmission. And most surprisingly, it has been discovered that the ideal can be achieved wherein both the water vapor transmission rate and the resistance to noxious or harmful chemicals even at elevated conditions of relative humidity may be improved simultaneously, resulting in selectively permeable materials capable of concurrently providing improved comfort with improved protection.
Accordingly, it is an object of this invention to provide lightweight and pliable selectively permeable materials that exhibit high degrees of breathability in conjunction with protection over a wide range of conditions. It is an object of the present invention to provide a selectively permeable protective covering capable of transmitting high quantities of water vapor while also being capable of adequately restricting the passage of noxious or harmful chemical vapors, even under conditions of high humidification. The chemical protective covering of this invention may be used for chemical protective articles of clothing that are comfortable because of their ability to allow the efficient evaporation of perspiration via transmission of water vapor and are suitable for application in a broad range of conditions likely to be encountered in realistic use scenarios.
In its broadest aspect, the chemical protective and water vapor permeable covering of this invention comprises a selectively permeable sheet of a polyamine polymer wherein at least 10% of the polyamine polymer amines are amine-acid moieties wherein the acidic species of said amine-acid moieties have a pKa less than 6.4. The materials are selected and adjusted via experimentation to achieve a chemical protective covering which has a water vapor transmission rate greater than 2,000 g/(m2*day) and a permeability to bis-2-chloroethyl sulfide of less than 0.02 cm/sec, preferably less than 0.002 cm/sec, and more preferably less than 0.0002 cm/sec.
In one embodiment, the polyamine polymer with amine-acid moieties is part of a selectively permeable composite sheet where the polyamine polymer forms a substantially continuous layer residing essentially on the surface of a water vapor permeable substrate which may be an open pore substrate, a closed pore substrate, or a void-free substrate.
In further embodiments of the invention, the polyamine polymer with amine-acid moieties is part of a selectively permeable composite sheet with an open pore substrate, where at least a portion of the polyamine polymer resides within the substrate.
In another embodiment of the invention, the chemical protective covering is comprised of two water vapor permeable open pore polytetrafluoroethylene substrates and a polyalkyleneimine-containing polyamine polymer with amine-acid moieties specifically involving H2SO4 and at least 25% of the polyamine polymer amines. These materials are made to form a selectively permeable composite sheet where the polyamine polymer forms a substantially continuous layer residing between the substrates, with at least a portion of the polyamine polymer residing within each substrate.
The invention is particularly useful as or within articles of clothing such as garments, gloves, footwear, and the like.


An isolation system adapted to permit simultaneous operation of at least colocated radio transceivers operating at different frequencies into at least one antenna by means of a single hybrid transformer having said at least one antenna coupled to one conjugate port, at least one broadband impedance simulator coupled to the other conjugate port and wherein said transceivers are respectively coupled to sum and difference ports of the hybrid transformer.

This invention relates generally to communications apparatus and more particularly to an antenna system employing a hybrid transformer to achieve isolation between radio transceivers operating on different radio frequencies.
The present trend in radio communications is to permit two or more colocated parties to communicate simultaneously on separate radio transceivers. For example, several air traffic controllers located within a small control tower must be able to communicate with their respective aircraft. Likewise, an aircraft may employ several different radios and antennas for communicatons which must be operable simultaneously. Still another application involves that of relaying or retransmission of radio signals in which an incoming signal is received at one frequency, demodulated and retransmitted at another frequency.
The communications systems require the use of special antenna systems which are adapted to prevent locally generated strong transmitted radio signals from interferring with simultaneously received weak incoming radio signals. Even if the transmitting and receiving frequencies are widely diverse, interference may still nevertheless be severe. In some cases where sufficient space is available, the transmitting antenna is installed a relatively far distance from the receiving antenna so that interference is diminished to an acceptable level.
In the case of airborne radio systems or in small portable, transportable or vehicular systems, it is not possible to widely space the antennas and consequently it becomes extremely difficult to control and minimize cross-talk interference between colocated transmitters and receivers. Where the wavelength is short, it has been found possible to effect reduced interaction of transmitting and receiving antennas by arranging them in colinear relationship; however, where the wavelength is not short it is necessary to resort to other methods for controlling interference.
One known method for reducing cross-talk interference is by the use of one or more four port hybrid transformers. Such apparatus is taught, for example, in U.S. Pat. No. 3,518,684 entitled "Duplex Antenna Systems for Aircraft Transceivers," H. Brueckmann, June 30, 1970, and U.S. Pat. No. 3,781,684, entitled "Single Antenna Repeater System Utilizing Hybrid Transformers," H.E. Inslerman, Dec. 25, 1973, both patents of which are assigned to the assignee of the present invention.

The United States ofAmerica as represented by the Secretary of the Army


A cookware handle with a soft non-slip surface is formed by molding elastomeric composition around a core or elongated member that connects a flange portion and the terminal end or hanging portion of the handle. The core or elongated member has a relatively narrow cross-section to minimize heat transfer from the pot so that the gripping portion remains cool during cooking.

The present invention relates a handle for an article of cookware, and more particularly to a cookware handle having a soft but resilient grip portion that is thermally insulating.
Cookware handles are primarily fabricated of metal or polymers, in particular, thermoset resin such as phenolic plastic and the like. Regardless of the type of material used to form a cookware vessel handle, an important attribute to many consumers is that it remain cool during cooking. This is preferably accomplished by first minimizing heat transfer from the cookware article, and second, in the case of metal handles, providing a high surface area for the radiation of heat from the handle. To the extent that a cookware article is fabricated at least in part from plastic, the superior thermal insulating properties of plastic minimize heat transfer to the grip portion held by the user.
Another important attribute of a cookware handle is that the grip is not slippery, with such property being exacerbated when the user's hands are wet or the contaminated with cooking oil and the like. Further, many consumers now prefer kitchen utensils that also have a grip portion of a soft resilient material, such as a rubber or elastomer.
From a utilitarian standpoint the cookware handle must be strong enough to support the cookware vessel. Further, as most cookware is now stored by hanging from a hole situated on the end of the cookware handle beyond the gripping region, it is preferable that metal, rather than plastic be used for such cookware handles.
Metal cookware handles covered by a non-slip rubber sleeve are known however, the sleeve being intentionally thin does not provide a soft grip.
It is therefore an object of the present invention to provide a handle for an article of cookware does not reach excessive temperatures during cooking at a very soft rubber grip portion, to reduce the stress on the user's hands and provide a non-slip surface.


The invention provides a device for use as a fire stop, which comprises a material that intumesces on exposure to heat, a patch of an adhesive connected to a surface of the material and a liner that covers the adhesive and is readily detachable from the adhesive by means of a pull, to expose the adhesive.

Partitions in general, including walls, floors and ceilings in buildings, may have holes in them for passage of items such as vent pipes, drain pipes, plumbing pipes, gas pipes, electrical wiring, conduits to contain electrical telephone and computer wiring, optical fibre, air conditioning ducts, heating ducts and the like. One hole may accommodate one or several such items. Annular spaces between the hole and the item passing through the hole create passages through which heat and fire can spread, especially if a pipe collapses or burns under the influence of heat. It is therefore desired to provide means for filling or blocking these spaces to prevent the spread of heat and fire through the holes. There are devices and materials known for this purpose. These have the disadvantages as they are cumbersome to apply, require tools and skills for their installation, and may require use of metal frames and screws or grout or caulking for their permanent installation. They may require that a seal to prevent passage of heat and fire is formed at the moment of installation. Such devices and materials make reentry to repair or to retro-fit piping and cabling systems difficult. Furthermore, in many cases subsequent visual inspection does not readily reveal whether the device or material has been properly installed or not.
It is an object of the present invention to alleviate some or all of the above-mentioned disadvantages.
The present invention provides a device that comprises a material that intumesces on exposure to heat, a patch of an adhesive connected to one surface of the intumescent material and a liner that covers the adhesive and is readily detachable from the adhesive by means of a pull, to expose the adhesive.
In another aspect the invention provides a method of providing a fire stop in a space between a hole in a partition and an item passing through the hole, which method comprises wrapping around the item a device as defined above, sliding the device along the item into the hole and pulling on the pull tab to expose adhesive and anchor the device permanently on the item by means of the adhesive.
In the description of preferred embodiments that follows, for purposes of illustration reference is made to a pipe passing through a hole. It should be appreciated that the pipe is merely representative of items that may pass through a hole, and examples of such items are mentioned above.
When the device is in place in a hole and heat from fire is encountered, the intumescent material swells markedly, thereby blocking the hole and preventing passage of heat, flame, smoke and the like. Suitable intumescent materials include flexible fire barrier felts that are disclosed in U.S. Pat. No. 5,830,319, the disclosure of which is incorporated by reference. The felt comprises an organic polymeric binder, organic fibres having pendant hydroxyl groups, for example cellulosic fibres, a heat absorbing compound that is suitably an intumescent compound, for example intercalated graphite, mica, perlite, vermiculite, hydrated sodium silicate, and a phosphorus compound.
One such intumescent material that is suitable for use in the present invention is a flexible fire barrier felt that is available from 3M under the trade-mark Interam Ultra GS. It is available in strips about 2 inches wide and about_inch thick in any length. When exposed to temperatures of at least 300xc2x0 F. (149xc2x0 C.) it intumesces rapidly, expanding up to approximately 25 times its original volume. It turns into a hard char that impedes or prevents passage of heat, fire, smoke and gases. The material exerts substantial pressures on items in the hole so that it compresses piping and wiring materials, thus further effecting a seal of the hole against fire, heat, smoke and the like. It also releases chemically bound water that helps to slow temperature rise.
In one simple embodiment of the invention, suitable for use with small holes and small pipes, the patch of adhesive is present directly on a surface of a strip of an intumescent fire barrier felt. The liner is removed from the patch of adhesive, the felt is flexed to permit it to be pushed into the hole and the adhesive attaches either to the exterior surface of the pipe or the interior surface of the hole, where it is held permanently in place. In another simple embodiment the intumescent felt strip is contained in a coating of, for example, a plastic sheet, woven fabric or, preferably, aluminum foil and the adhesive patch is on the coating. The intumescent felt material and the adhesive are operatively connected to each other via the coating, although not in direct physical contact. The coating contains the intumescent material when it first encounters heat and intumesces, so that the expanded material remains contained in the hole and blocks the hole, rather than perhaps being blown around by a fire draught and leaving the hole unblocked. These embodiments are more suited for use with small pipes, up to about 1 inch nominal diameter, and small holes, up to about 1xc2xd inch nominal diameter.
For use with pipes larger than 1 inch and holes larger than 1xc2xd inch it is preferred to enclose the intumescent material in a container.
The container surrounding the intumescent material is preferably flexible and has a certain degree of strength. Suitable materials for the flexible container include plastics materials and mention is made of polyolefins, particularly polyethylene, which heat will melt and may assist in sealing. Another flexible container material that can be used is a metal foil, such as aluminum foil. Yet another material is a fabric, for instance woven fibres of polyamide, polyester, polyolefin, polyacrylate, glass or ceramic or the like. A preferred container, particularly for more stringent conditions, is composed of a thin aluminum sheet or foil attached to a fabric or fiber reinforcing material made of, for instance, polyamide, polyester, glass, ceramic or the like. Suitable materials include fabric net reinforced aluminum foils with polyethylene heat seal layer available from Alpha Associates, Inc., of Woodbridge, N.J., U.S.A particularly the foil available under the designation Alpha) Style 4413-VLS(trademark).
To make a device for use with pipes sizes of about 1xc2xd a inch nominal and greater, the flexible container, when laid flat, is normally elongate and in use is folded to bring one end into contact with the other to form an annulus. In a preferred embodiment the two ends are held in contact by some means. The particular means for holding the ends is not critical. Persons skilled in the art will be able to suggest many possible means for this purpose, for instance a clip or clamp, or tape, or Velcro. Preferred is an adhesive covered with a detachable liner, so that the annulus can be readily made simply by detaching the detachable liner and pressing the two ends of the container together to be held by the adhesive. The demands on this adhesive are not particularly stringent, and suitable adhesives are available from 3M under the designation Scotch(trademark) 467 HiPerformance Adhesive and 468 HiPerformance Adhesive.
A device of the invention can be made by taking a sheet of the flexible material that will form the container. The sheet should be of the approximate length required for the maximum length of the container when flat, plus, if necessary, an allowance for sealing at each end to enclose the intumescent material. It should be of a width sufficient to encompass both the width and the height of the unexpanded intumescent material, plus again, if necessary, an allowance for sealing along one edge. The material can then be folded over the unexpanded intumescent material and sealed along one side and both ends, to form the required enclosure. One suitable way of doing this is by heat sealing, although it is again clear that this could be done by many other means, for instance use of adhesive or even stitching. The flexible container should not be a tight fit over the intumescent material, so that when the intumescent material does swell some of that swelling is accommodated before the flexible container becomes stressed by the swelling. It is important that the flexible container contain the intumescent material as it first swells on encountering the heat, so that the intumescent material stays in place and is trapped in the hole, surrounding the pipe that passes through the hole. The container holds the swelling material for at least this brief initial period of time. Even if a seal bursts or the container subsequently tears the expansion of the intumescent material in the confined space will hold at least the bulk of the expanded material in place and form an effective fire stop.
In order to locate the device permanently around the pipe and in a hole that is to be blocked, use is made of the patch of adhesive that is on one exterior surface of the container. That adhesive can be on the surface that becomes the inner surface when the device is formed into an annulus. The installation of the device is not particularly critical, provided that it adheres to the pipe, as the seal is not formed on installation but is formed only when heat causes the intumescent material to intumesce. On installation the device is wrapped around a pipe to form an annulus, or collar, using the adhesive or other sealing means at either end of the container to form the annulus, then thrust into the hole. Once the device is in the desired location a pull tab, which attaches to or is integral with the liner on the adhesive patch and projects from the hole, is pulled to remove the liner from over the adhesive patch. During insertion of the device in a hole there is usually some degree of friction between the inner surface of the device and the pipe that tends to help in holding the device in place before the exposure of the adhesive patch to form the permanent bond. The adhesive then comes in contact with the pipe and the device is held permanently by the adhesive at the desired location. The pull tab and liner, which at its one end is permanently attached to the container, projects from the hole and serves as a flag or marker to indicate that the device is in place. At this stage, or at any subsequent inspection, the hole can readily be examined visually to see that the device is in place in the hole, as indicated by the flag. Adhesion between the strip of adhesive on the inner surface of the annulus and the outer surface of the pipe can also be checked, of course.
Also within the scope of the invention is a device similar to that described in the immediately preceding paragraph, but differing in having the adhesive patch on the surface that becomes the outer surface when the device is formed into an annulus. With this device the adhesive attaches to the inside of the hole, rather than the exterior of the pipe. One application of this device is in a partition wall composed of studs faced on both sides with gypsum wallboard. For effective fire-stopping it is necessary to use two fire stops, one in each piece of wallboard, or to insert a sleeve that extends through the two pieces of wallboard and spans the gap that is equal to the width of the studs. In this case one fire stop can be inserted in the sleeve, which is, for example, of PVC or of 24 or 28 gauge sheet metal. The device can be held in place by the adhesive patch adhering the outer surface of the device to the inner surface of the sleeve.
As stated above, with the device of the invention the seal to prevent passage of heat, smoke, flame, etc. is not formed on installation, but is formed on exposure to heat causing rapid expansion of the intumescent material. The rapidly expanding intumescent material occupies whatever space is available, so it accommodates awkward shapes with ease. For instance, sometimes in a hole there is a pipe in which there is an elbow or a coupling between two pipes of different diameter, or two or more small pipes passing through one hole. These create awkward shapes and present problems for fire stops composed of rigid material and designed to form a seal immediately on installation. They present no problem with the fire stop of the present invention, however, as the intumescent material expands into whatever shape of space is available to form the required seal.
The intention is that the adhesion between a surface of the fire stop device and the outer surface of the pipe, or the inner surface of the hole, as the case may be, shall be permanent, and shall therefore be able to withstand variations in temperature, exposure to conditions of moisture, lack of humidity, vibration, exposure to gases and any other condition which might tend to reduce or break the adhesion. The demands on this adhesive material are therefore greater than the demands on the material joining the two ends of the container to form an annulus. If the latter adhesion should fail this is of no effect, because the device is still retained in place. In contrast, the adhesive holding the device to the pipe must remain in place and should therefore have the capacity of adhering to materials that have low surface energy. Suitable adhesives are known, for instance, from U.S. Pat. Nos. 5,602,221; 5,616,670 and 5,654,387 the disclosures of which are incorporated herein by reference. One adhesive for this purpose is available from 3M under the trade-mark Scotch 300LSE HiStrength Adhesive. It should be borne in mind that fire stop devices of the same construction might be used on pipes made of many different materials, such as various plastic materials, including but not limited to cellular core PVC (ccPVC), PVC, crosslinked PVC (CPVC), fire resistant polypropylene (FRPP), PVDF, ccABS and ABS, steel, galvanized steel aluminum, copper or mild steel which may have an anticorrosive oil finish, or be painted, and the adhesive should attach permanently and firmly to any of these materials.
Pipes and conduits used in buildings tend to be of certain nominal sizes. There is some variation in external diameter, because diameters quoted are often internal diameters and different pipes for different purposes have different wall thicknesses. The outer diameters of pipes encountered in buildings are clustered in various fairly narrow dimensional ranges, however, and a device of appropriate size is made for each range.
Alternatively, or in addition to sizing devices with regard to the pipe size it is possible to size them with regard to the hole size.
Usually in construction a hole to accommodate a pipe passing through it is sized so that the diameter of the pipe is about 50 to 80% of the diameter of the hole. In this case one appropriately sized device of the invention is all that is needed to form a fire stop. In some instances, however, it is necessary to insert a fire stop where the hole is much larger than the pipe. This is the case particularly when retrofitting, when, say, a 3 inch pipe may have been removed from a hole and in the retrofit a 1 inch pipe is passed through the hole. In such a case it is possible to use two devices of the invention. Immediately around the 1 inch pipe is placed a device appropriately sized for 1 inch pipe, and around that there is placed a second, larger device of the invention. Alternatively the hole can be partially filled with some non-combustible material, for example mineral wool.
As stated above, after installation of the device the pull tab can serve as a flag. The flags can be coded to indicate the size of the device, for instance with different colours.


A water based liquid tooth cleaning gel is presented with a viscosity below 50 Paxc2x7s (20xc2x0 C.) comprising

This invention relates to liquid tooth cleaning preparations containing polishes, humectants and water which contain an antimicrobial 5-aminohexahydropyrimidine as a tartar-inhibiting component.
1,3-bis-(2-ethylhexyl)-5-methyl-5-aminohexahydropyrimidine is known as an antiseptic component by the name of hexetidine in oral hygiene and dental care preparations, for example from patent applications GB 2 001 526 A1, EP 0 229 375 A1, DE 3729401 A1 and EP 0 408 174 A1.
However, the prior art literature cited above does not disclose a liquid tooth cleaning preparation which contains this tartar-inhibiting component in a formulation containing polishing agents. The production of liquid tooth cleaning preparations with polishing components dispersed therein imposes stringent demands on the stability of such systems against sedimentation. Another problem is to incorporate tartar-inhibiting agents in such preparations without affecting transparency or the effectiveness of those agents. Finally, tooth cleaning preparations of the type in question are also supposed to contain other components to counteract the demineralization of dental enamel.
The present invention relates to a water-based liquid tooth cleaning gel with a viscosity below 50 Paxc2x7s (20xc2x0 C.), characterized by a content of
Liquid in the context of the present invention means a viscosity of less than 40 mPaxc2x7s (as measured at 20xc2x0 C. with a Brookfield RVF rotational viscosimeter, spindle xc2xe at 4 r.p.m. corresponding to a shear rate D of 4 Sxe2x88x921) which provides for dispensing from a small flexible bottle by light pressure and ensures that the gel sinks slowly into the bristles of the toothbrush.
The tooth cleaning gels according to the invention preferably also have a certain transparency. The transparency and viscosity according to the invention are achieved through the choice and quantity of the polishing components, thickeners and humectants used. It has been found that the transparency of the compositions is improved by the content of the magnesium salt. In addition, the magnesium salt makes a valuable contribution to the remineralizing effect of the tooth cleaning gel.
Suitable silica polishing components are any silica gels, silica hydrogels and precipitated silicas known as polishes. Silica gels are obtained by reacting sodium silicate solutions with strong aqueous mineral acids to form a hydrosol, ageing to form the hydrogel, washing and drying. If drying is carried out under moderate conditions to a water content of 15 to 35% by weight, the so-called silica hydrogels known, for example, from U.S. Pat. No. 4,153,680 are obtained. Drying to water contents below 15% by weight results in irreversible shrinkage of the previously loose structure of the hydrogel to the dense structure of the so-called xerogel. Silica xerogels are described, for example, in U.S. Pat. No. 3,538,230.
A second particularly suitable group of silica polishing agents are the precipitated silicas. Precipitated silicas are obtained by precipitation of silica from dilute alkali metal silicate solutions by addition of strong acids under conditions which preclude aggregation to the sol and gel. Suitable processes for the production of precipitated silicas are described, for example, in DE-OS 25 22 486 and in DE-OS 31 14 493. A particularly suitable precipitated silica is that produced in accordance with DE-OS 31 14 493 which has a BET surface of 15 to 110 m2/g, a particle size of 0.5 to 20 xcexcm (at least 80% by weight of the primary particles should be below 5 xcexcm in size) and a viscosity in the form of a 30% glycerol/water (1:1) dispersion of 30 to 60 Pa.s (20xc2x0 C.) and which is used in a quantity of 10 to 20% by weight, based on the tooth gel. In addition, particularly suitable precipitated silicas of this type have rounded corners and edges and are commercially obtainable under the name of Sident(copyright)12 DS (DEGUSSA). Another suitable silica is Zeodent 113 (Huber Corp.) with a BET surface of 150 to 250 m2/g.
Other precipitated silicas of this type are Sident 8 (DEGUSSA) and Sorbosil AC 39 (Crosfield Chemicals). These silicas are distinguished by a weaker thickening effect and a slightly larger mean particle size of 8 to 14 xcexcm for a specific BET surface of 40 to 75 m2/g and are particularly suitable for liquid tooth gels according to the present invention.
Other polishes, particularly those which are detrimental to the transparency of the compositions but which, even in small amounts, considerably increase cleaning performance may optionally be present in quantities of less than 2% by weight. Such polishing components are, for example, pumice, zirconium silicate or gamma-aluminium oxide.
Of crucial importance to the rheology and transparency of the liquid tooth cleaning gels according to the invention is the composition of the liquid carrier phase of water and humectants. The total quantity of 40 to 60% by weight of the humectant combination is based on the tooth cleaning gel as a whole and consists essentially of sorbitol, glycerol and polyethylene glycol. Suitable polyethylene glycols are both low molecular weight and high molecular weight polyethylene glycols, i.e. those with average molecular weights of 200 to 10,000.
Where large amounts of sorbitol and small amounts of glycerol are used, a relatively high molecular weight polyethylene glycol should generally be employed. In a preferred embodiment, the humectants sorbitol (a), glycerol (b) and polyethylene glycol (c) are present in the tooth cleaning gels according to the invention in a ratio by weight of (a) to (b) to (c) of 10:(0-8):(0.2-2).
The water content of the tooth cleaning gels according to the invention is in the range from 25 to 35% by weight and is the sum of the quantities of water introduced by the raw materials, such as the 70% sorbitol or the 86% glycerol for example, and the quantities separately added. The quantities of sorbitol and glycerol mentioned are based on water-free active substances.
Suitable water-soluble magnesium salts are both inorganic salts such as, for example, MgCl2, MgF2, MgSO4 and hydrates thereof and organic magnesium salts such as, for example, the magnesium salt of glycerophosphoric acids (magnesium glycerophosphate), glycolic acid, lactic acid, citric acid, gluconic acid, glutamic acid or aspartic acid. Magnesium is preferably used in the form of MgSO4.7H2O.
Suitable antimicrobial 5-aminohexahydropyrimidines are known, for example, from U.S. Pat. No. 2,837,463. A product particularly suitable for use in dental care preparations is 1,3-bis-(2-ethylhexyl)-5-methyl-5-amino-hexahydropyrimidine which is also known by the name of hexetidine. For incorporation in the tooth cleaning gels according to the invention, the 5-aminohexahydropyrimidines may be used in free form or even in the form of their soluble salts, for example the sulfates, chlorides, fluorides, hydrogen phosphates, lactates, glycolates, citrates or salts of organopolyphosphonic acids, for example 1-hydroxyethane-1,1-diphosphonic acid or azacycloheptane-2,2-diphosphonic acid. The only requirement is that at least 0.01% by weight of the 5-aminohexahydropyrimidine should be present in dissolved form in the composition.
In addition to the compulsory components mentioned, the tooth cleaning gels according to the invention may contain 1 to 10% by weight of other toothpaste ingredients. Such ingredients are, for example, binders, surfactants, flavors and sweeteners, scale inhibitors, fluorine compounds, vitamins, panthenol and other active substances.
Suitable binders are, for example, natural and/or synthetic water-soluble polymers, such as alginates, carrageenates, tragacanth, starch and starch ethers, cellulose ethers such as, for example, carboxymethyl cellulose (Na salt), hydroxyethyl cellulose, methyl hydroxypropyl cellulose, guar, acacia gum, agar agar, xanthan gum, succinoglycan gum, locust bean gum, pectins, water-soluble carboxyvinyl polymers (for example Carbopol(copyright) types), polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycols, more particularly those with molecular weights of 1,500 to 1,000,000.
Particularly suitable binders are xanthan gum, carboxymethyl cellulose, polyvinyl pyrrolidone and mixtures of these water-soluble polymers which may be present in a quantity of up to 1.0% by weight.
Suitable surfactants are, for example, sodium alkyl sulfates containing 12 to 18 carbon atoms in the alkyl group. These compounds also have an enzyme-inhibiting effect on the bacterial metabolism of tartar. Other suitable surfactants are alkali metal salts, preferably sodium salts of alkyl polyglycol ether sulfate containing 12 to 16 carbon atoms in the linear alkyl group and 2 to 6 glycol ether groups in the molecule, of linear alkane (C12-18) sulfonate, of sulfosuccinic acid monoalkyl (C12-18) esters, of sulfated fatty acid monoglycerides, sulfated fatty acid alkanolamides, sulfoacetic acid alkyl (C12-16) esters, acyl sarcosines, acyl taurides and acyl isethionates containing 8 to 18 carbon atoms in the acyl group.
Ampholytic and zwitterionic surfactants, more particularly betaine surfactants, for example cocoalkyl betaine or cocoacylamidopropyl betaine, are also suitable. Finally, nonionic surfactants, for example ethoxylates of fatty acid mono- and diglycerides, of fatty acid sorbitan esters and alkyl (oligo)glucosides, may also be used.
In a particularly preferred embodiment, the tooth cleaning gels according to the invention contain a water-soluble binder and a surfactant combination of anionic, zwitterionic and nonionic surfactants as further ingredients.
Flavors and sweeteners are normally used for flavoring. Suitable flavors are, for example, peppermint oil, spearmint oil, eucalyptus oil, aniseed oil, fennel oil, caraway oil, methyl acetate, cinnamaldehyde, anethol, vanillin, thymol and other natural or nature-identical essential oils or even synthetic flavors.
Suitable sweeteners are, for example, saccharin sodium, acesulhpam, aspartame, sodium cyclamate, steviosides, thaumatine, sucrose, lactose, maltose or fructose, glycyrrhizin, etc.
Suitable scale inhibitors are, for example, organic phosphonates, such as azacycloheptane-2,2-diphosphonic acid disodium salt or 1-hydroxyethane-1,1-diphosphonic acid tetrasodium salt.
Suitable fluorine compounds are, for example, sodium fluoride and sodium monofluorophosphate (Na2PO3F).
The vitamins present may be selected, for example, from retinol, panthenol or a salt of pantothenic acid, ascorbic acid or salts or esters thereof or mixtures thereof. In a preferred embodiment, a combination of panthenol and retinol is present for improving the inflammation-inhibiting properties.
The tooth cleaning gels according to the invention may additionally contain typical toothpaste ingredients, for example
buffering agents, for example primary, secondary or tertiary alkali metal phosphates, citric acid/sodium citrate,
wound-healing and anti-inflammatory agents such as, for example, urea, allantoin, camomile-based active principles (azulene), alkali metal thiocyanate, acetylsalicylic acid derivatives,
lower alcohols, for example ethanol or isopropanol,
dyes and pigments,
preservatives such as, for example, benzoic acid, sorbic acid and salts thereof, p-hydroxybenzoic acid esters.
The following Examples are intended to illustrate the invention.

Plaque-controlling liquid tooth cleaning gel


The present invention relates to a liquid dual phase cosmetic or pharmaceutical composition comprising an oil phase and an aqueous phase, the composition containing as a demixing agent a film forming agent such as polyvinylpyrrolidone and derivatives thereof. The compositions of the invention are particularly useful as makeup removers.

The present invention relates to cosmetic compositions. In particular, the invention relates to two-phase cleansing compositions which are particularly useful in makeup removal
Dual phase skin cosmetic compositions are currently very popular, in that they provide a broad range of cleansing/conditioning potential within a single product, and are also aesthetically appealing to the consumer. Typically, the dual phase product contains an aqueous phase and an oil phase, each adapted to removing a particular type of residue from the skin, or delivering a particular type of active In a common use, for example, the aqueous phase of a dual phase cleansing composition is designed to remove water-soluble material from the skin, while the oil phase is designed to remove oil-based, or xe2x80x9cwaterproofxe2x80x9d material from the skin.
A number of factors must be considered in making a successful dual phase product. For example, in order to function properly, the two phases must be vigorously mixed, providing a temporary apparently homogeneous single phase product which delivers both phases to the region to be treated simultaneously. This typically means that the product must contain one or more surfactants or emulsifiers, which will render the two phases at least temporarily compatible during the mixing and application stage Surfactants are also frequently useful in the removal of waterproof makeup. Unfortunately, many such emulsifiers are drying to the skin and/or are Irritating to users, and in particular cannot be routinely used in the eye area.
On the other hand, however, it is also desirable that the two phases separate quickly after use, as the emulsified product has a cloudy appearance that is unappealing to consumers. After prolonged, continuous mixing of the two phases during regular use, the time it takes for the phases to separate becomes longer and longer, and the product rapidly loses its initially attractive appearance. Moreover, oil soluble actives may be unstable if they remain in prolonged contact with the aqueous phase, and therefore, the amount of time spent in contact with the water phase should be minimized. As can readily be seen, these two aspects of the dual phase product, namely, the need for rapid and complete emulsification followed by rapid and complete separation, are at odds with each other, and to achieve both satisfactorily in a single product, in a way that is both cosmetically acceptable and attractive to the user, is often difficult The present invention, however, provides a dual phase product in which the phases mix well and completely, and yet demixing is accomplished rapidly after use Moreover, the product is non-irritating, and when used as a makeup remover, is highly successful in removing even the most difficult to remove oil-based cosmetics
The present invention relates to a liquid dual phase cosmetic or dermatological composition comprising an aqueous phase and an oil phase, at least one of the phases containing as a demixing agent, a film forming agent In a preferred embodiment, the demixing agent is a polyvinylpyrrolidone (hereinafter referred to as xe2x80x9cPVPxe2x80x9d) or a copolymer thereof The compositions of the invention are particularly useful when employed as a makeup remover, but may also be used for skin conditioning, or delivery of cosmetic or therapeutic active agents to the skin for the treatment and/or amelioration of various skin conditions.
The demixing agents used in the present dual phase compositions are well-known in the art for being useful as film forming agents and for being useful in improving water resistance and wear of compositions However, it has not been previously known that they can be used to facilitate rapid separation of phases in a two phase emulsion. In addition to this function, however, these demixing agents have the additional advantage of being extremely mild, and non-irritating. In particular, they do not appear to cause any irritation when in contact with the eye, which cannot be said of many other demixing agents.
Any film-forming agent may be used in the compositions of the invention. Examples of useful categories of demixing agents include acrylic acid polymers and copolymers, such as cyclo alkyl methacrylate copolymer; chitin or chitosan or derivatives thereof, or polyquaternium film formers, such as polyquaternium-11. A preferred demixing agent is PVP or a copolymer thereof. Particularly preferred are PVP/hexadecene copolymer and/or PVP/polycarbamyl polyglycol ester. PVP/hexadecene copolymer is available commercially under the tradename Ganex V-216 (copyright), from ISP Sutton Labs of Chatham, N.J. Other demixing agents include for example, PVP/dimethylaminoethylmethacrylate copolymer, PVP/eicosene copolymer, PVP/ethyl methacrylate/methacrylic acid copolymer, PVP/VA copolymer, PVP/1-triacontene, and listings of film formers in the CTFA Cosmetic Ingredient Handbook, incorporated herein by reference.
The demixing agent is added to either the oil phase or the water phase of the composition, usually in an amount of from about 0 001 to about 10 percent, preferably in an amount of about 0.01 to about 1 percent. Dual phase compositions prepared with such a demixing agent emulsify rapidly and uniformly upon vigorous shaking, and demulsify completely upon resting within approximately 5 to 20 minutes. The remainder of the composition is formulated depending on the nature of the desired end product The ratio of the oil phase to aqueous phase is not critical, and can be vaned in accordance with the type of product, but will generally be between 30:70 to 70:30, more preferably between 40.60 to 60.40 Most preferably, the aqueous phase is present as a higher weight percent than the oil phase. The aqueous phase may be any cosmetically acceptable water based material, such as deionized water, or floral water.
The oil phase may be any cosmetically or pharmaceutically acceptable oil, such an oil being defined for the present purpose as any pharmaceutically or cosmetically acceptable material which is substantially insoluble in water. As the oils can perform different functions in the composition, the specific choice is dependent on the purpose for which it is intended. The oils may be volatile or non-volatile, or a mixture of both. For example, suitable volatile oils include, but are not limited to, both cyclic and linear silicones, such as cyclomethicone, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane, or straight or branched chain hydrocarbons having from 8-20 carbon atoms, such as decane, dodecane, tridecane, tetradecane, and C8-20 isoparaffins.
Non-volatile oils include, but are not limited to, vegetable oils, such as coconut oil, jojoba oil, corn oil, sunflower oil, palm oil, soybean oil, carboxylic acid esters such as isostearyl neopentanoate, cetyl octanoate, cetyl ricinoleate, octyl palmitate, dioctyl malate, coco-dicaprylate/caprate, decyl isostearate, myristyl myristate, animal oils such as lanolin and lanolin derivatives, tallow, mink oil or cholesterol; glyceryl esters, such as glyceryl stearate, glyceryl dioleate, glyceryl distearate, glyceryl linoleate, glyceryl myn state, non-volatile silicones, such as dimethicone, dimethiconol, dimethicone copolyol, phenyl trimethicone, methicone, simethicone; and non-volatile hydrocarbons, such as isoparaffins, squalane, or petrolatum.
The composition also may contain other cosmetically or therapeutically useful components. It may, for example, be desirable to incorporate other surfactants into the formulation, again depending on the intended purpose of the formulation, for example, as cleansing agents to assist in wetting skin, emulsifying oils or solubilizing soil on skin or as foaming agents. The surfactants employed may be any that are traditionally used for cosmetic or pharmaceutical purposes, and may be selected from nonionic, anionic, cationic or amphoteric surfactants, the identities of which are well known to those skilled in the art. Additional surfactants may be distributed in either or both of the phases of the formulation, and selection is limited only by a given surfactant""s compatibility with the phase into which it is incorporated, and by the location to which the composition is to be applied. Other potentially useful components of the formulation include emollients, humectants, fragrances, preservatives, and buffers. Such materials are routinely used in cosmetic products, and listings of appropriate materials can be found, for example in the International Cosmetic Ingredients Handbook, Third Edition, 1996 (CTFA).
As noted above, the formulation can also be used for therapeutic or quasi-therapeutic purposes, and therefore may also comprise useful active ingredients, for the purposes of treating both the skin and hair. Useful active ingredients include, but are not limited to antioxidants, antimicrobials, sunscreens, analgesics, anesthetics, anti-acne agents, antidandruff agents, antidermatitis agents, antipruntic agents, anti-inflammatory agents, antihyperkeratolytic agents, anti-dry skin agents, antiperspirants, antipsoriatic agents, antiseborrheic agents, hair conditioners and hair treatment agents, antiaging agents, antiwrinkle agents, antihistamine agents, skin lightening agents, depigmenting agents, wound-healing agents, vitamins, corticosteroids, tanning agents, or hormones. The location of the active in the formulation is determined by its solubility and/or stability in either oil or water.
The formulations of the present invention are useful for a variety of purposes, including skin or hair cleansers, skin or hair treatment products, sunscreen or suntanning products, and the like. In a particularly preferred embodiment, however, the composition is used for removing makeup. As already noted, the demixing agents, because of their mildness, are eminently well-suited to being employed in a product which is usable around the eye. When combined with an appropriate group of additional components, particularly in the oil phase, the resulting makeup remover successfully cleans skin surfaces, particularly eyes and lips, of even the most transfer-resistant of currently used cosmetics, while remaining gentle and non-irritating to the user.
In this preferred embodiment, the oil phase contains a combination of both volatile and non-volatile oils. The volatile oil portion is preferably a volatile hydrocarbon present in amounts of from about 30-70%, and more preferably 40-60%, and the non-volatile present at about 0.1-10%, preferably 0.2-5% by weight of the total composition. In a particularly preferred embodiment, the oil phase contains a blend of oils comprising isododecane at 25-40% by weight of the total composition, a volatile C16 isoparaffin at 15-30% by weight of the total composition, and the non-volatile silicone at 0.1-1% by weight of the total composition.
The non-volatile portion of the oil phase is preferably a non-volatile silicone oil. A preferred non-volatile silicone is dimethicone In a particularly preferred embodiment, the amount of volatile oil used is considerably higher than that of the non-volatile oils; for example, the volatile oil will be present in an amount of about 30-70%, preferably about 40-60%, of the total composition, and the non-volatile oil in an amount of about 0.1-10%, preferably about 0.2-5% of the total composition.
In another embodiment, for example, the volatile oil portion contains a combination of a volatile silicone and a volatile hydrocarbon. More specifically, the oil phase contains a blend of oils comprising a low molecular weight cyclic silicone at 25-40% by weight of the total composition, a volatile C16 isoparaffin at 15-30% by weight, and the non-volatile silicone at 0.1-1% by weight of the total composition.
In this preferred embodiment, it may be desirable to provide an additional small amount of surfactant in the oil phase to facilitate removal of the cosmetic residue from the skin. The amount of surfactant added is preferably no more than 5%, and more preferably is in the range of 0.1-1%. The surfactant may be of any type, i.e., anionic, nonionic, cationic or amphoteric; however, if the makeup remover is intended for use in the eye area, it is preferred that the surfactant should be a mild surfactant, such as LIPO-PEG-2DL or disodium cocoaamphoidacetate (Miranol).
The invention is further illustrated in the following non-limiting examples


An aromatic carbonate polymer composition having improved thermal stability consisting of an aromatic carbonate polymer such as a polycarbonate or polycarbonate/polyester blend and an impact modifier which is free of alkali materials which catalytically degrade a polycarbonate. Also an impact modifier which is preferably of a shell-core structure prepared by the emulsion polymerization process and has a pH of about 3 to about 8. A preferred emulsifier is an alkyl sulfonate having an alkyl group of C6-C18 carbons.

The present invention is directed to an impact modified thermoplastic aromatic carbonate polymer composition having improved resistance to transesterification or degradation and improved thermal stability. More specifically the composition of this invention comprises in combination an aromatic polycarbonate resin and an impact modifier that essentially does not catalyze transesterification or degradation of an aromatic carbonate polymer composition.
Addition of rubbery impact modifiers is commonly used to improve the toughness of aromatic carbonate polymer compositions. In comparing the effectiveness of various rubbery modifiers large differences in melt stability are often observed. In aromatic carbonate polymer compositions, the polycarbonate portion of the composition is susceptible to degradation by acids-and bases. Sufficient degradation will cause color formation, loss of molecular weight, reduced chemical and mechanical properties and generation of carbon dioxide which causes surface appearance defects, such as splay in molded parts.
The problem of the melt stability of polycarbonates and blends thereof with other polymers are often addressed by the addition of various stabilizers as disclosed in copending application Ser. No. 08/79112 filed Jan. 30, 1997 and assigned to the same assignee and in U.S. Pat. Nos. 4,532,290, 5,252,536, 5,441,997, 5,502,119 and 5,608,027 all of which are incorporated herein by reference. Rubbery modifiers prepared by emulsion polymerization are useful in polymer blends as impact modifiers due to their fixed particle size. However, they may cause particular problems in the stability of polycarbonates due to the presence of significant amounts of additives employed in preparing the rubbery modifiers such as flow aids, polymerization catalysts, antioxidants and especially emulsifiers. Some of the most common impact modifiers employed in the preparation of a carbonate polymer compositions are polymers themselves prepared by: polymerization techniques employing particular emulsifiers that are utilized in emulsion polymerization reactions; suspension agents utilized in suspension polymerization reactions; surfactants utilized in phase transfer catalysis systems; soluble catalysts utilized in polymerization reactions; and for certain process stabilizers employed during the processing of the polymers either in the polymerization or in the molding thereof. For example, it is now known that residues in an impact modifier from these particular polymerization aids, particularly emulsion polymerization aids employed in preparing certain impact modifiers, quite often catalyze transesterification or degradation of polycarbonates. It is also known that impact modifier additives to carbonate polymer compositions are commonly made by emulsion polymerization processes employing alkali metal salts of fatty acid emulsifiers to stabilize the emulsion during polymerization of the impact modifier. It is also known that the alkali metal salts of fatty acids catalyze transesterification or degradation of polycarbonates which in turn causes inconsistent thermal stability in carbonate polymer composition because of residual amounts of the emulsifier employed in preparing the modifier remaining in the impact modifier. This leads to problems in molding shops because of the variability in viscosity due to the catalytic transesterification or degradation of polycarbonates with such impact modifiers.
U.S. Pat. No. 5,608,027 Table 11 describes the superior performance of complex stabilization systems when impact modifiers are used in polycarbonate compositions and demonstrates problems that can occur with reaction between the polycarbonate and the impact modifier, if complex stabilizers are not added to prevent the reaction.
A large number of patents exists describing the use of additives in polycarbonate compositions. A significant fraction of these are directed to the use of impact modifiers. The instant invention discloses the utilization of certain impact modifiers prepared by emulsion polymerization in carbonate polymer compositions, which impact modifiers are essentially free of particular residual emulsifiers that cause degradation of polycarbonates. The instant invention is directed to an impact modified carbonate polymer composition with better thermal stability than compositions with conventional impact modifiers which employ, for example, alkali metal salts of fatty acid as emulsifiers in the preparation thereof.
It has now been found that the basic cause of many melt instability issues in impact modified carbonate polymer composition and blends thereof with polyesters is the presence of residual amounts of certain emulsifiers such as alkali metal salts of fatty acids employed in preparing impact modifiers. Alkali metal carboxylates are especially troublesome.
Surprisingly, it has now been discovered that degradation of a polycarbonate is not seen when employing certain surfactants selected from sulfate, sulfonate or phosphate based ionic surfactants in preparing impact modifiers, particularly rubbery modifiers, by the emulsion polymerization process even though the same alkali metal ion may be present. Use of a sulfonate, sulfate or phosphate type surfactant allows preparation of a rubbery modifier by an emulsion polymerization process that even though containing residual amounts of the emulsifier in the carbonate polymer composition, does not result in significant polycarbonate degradation.
Sulfate, sulfonate or phosphate surfactants allow flexibility in the preparation of rubbery modifiers by emulsion polymerization techniques. They do not require acidification of the rubber (which could cause acid catalyzed degradation of polycarbonates or its blends) nor do they require extensive washing or other purification steps to reduce residual surfactant levels in the rubbery modifier. Since these surfactants do not as readily degrade polycarbonates, they can be left in the rubbery modifier.
Thus, this invention is directed to an impact modified aromatic carbonate polymer composition having improved stabilization to degradation or transesterification and improved thermal stability. It has been surprisingly discovered, for example, that when methylmethacrylate-butadiene styrene (MBS) impact modifiers are prepared using certain sulfonates, sulfates or phosphates as surfactants, the carbonate polymer compositions impact modified with such MBS impact modifiers have significantly improved melt and thermal stability. It is also preferred that the impact modifier have a pH of about 3-8. The general invention is directed to the improvement of the melt and thermal stability of polycarbonates by going backward in the process of making the impact modifiers that are utilized in the polymer. Specifically for carbonate polymer compositions, the impact modifier should be essentially free of such residual amounts of emulsifiers as alkali metal salts of fatty acids, alkali metal carbonates, and other basic materials, such as amines or ammonium salts. Some examples of such emulsifiers are metal salts of stearic acid such as sodium stearate, lithium stearate and the like, metal salts of oleic acid such as sodium and potassium oleate and the like, amines such as dodecyl dimethyl amine, dodecyl amine and the like, and ammonium salts thereof. On the other hand, when certain surfactants are utilized in preparing impact modifiers of this invention with polycarbonate containing compositions such as MBS impact modifiers, little or no degradation of the polycarbonate is noted. These surfactants are selected from the group of ionic surfactants consisting of alkyl or arylalkyl sulfonates, alkyl or alkylaryl sulfates, and alkyl or alkylaryl phosphates.
Therefore, it is an object of the invention to provide an impact modified polycarbonate composition having improved resistance to degradation.
Another object of this invention is to provide an impact modifier essentially free of basic materials such as alkali metal salts of fatty acids, alkali metal carbonates and other basic material such as amines and ammonium salts.
The instant invention is directed to a novel impact modifier which when employed in a carbonate polymer composition, the carbonate polymer composition has improved thermal stability by having improved resistance to degradation from the catalytic effect on the polycarbonate component of the composition due to the impact modifier being essentially free of certain emulsifiers. It was discovered that certain impact modifiers, prepared by emulsion polymerization, cause catalytic degradation of the polycarbonate. As such, degradation reduces the molecular weight of the polycarbonate thereby affecting physical, chemical and mechanical properties, including melt viscosity and processing.
In an emulsion polymerization process, such certain emulsifiers commonly employed are alkali metal salts of fatty acids. Alkali metal carbonates, or other basic materials may also be used. Such emulsifiers of the prior art are typically as set forth previously.
In preparing the impact modifiers with the above commonly employed emulsifiers, it has been found that residual amounts of the emulsifier can remain in the impact modifier. The amount of residual emulsifier depends on the method of recovering the impact modifier. Spray drying of the impact modifier usually results in a higher amount of emulsifier remaining. If salt coagulants or acid coagulants are employed in obtaining the final impact modifiers, more of the residual emulsifier maybe removed by the coagulant process, but sufficient amount of the emulsifier may still remain.
Applicant""s have now surprisingly discovered that by employing an impact modifier that is essentially free of certain emulsifiers in preparing an impact modifier by the emulsion polymerization process, an impact modifier is obtained which when employed in a carbonate polymer composition does not catalytically degrade the polycarbonate component of the composition even though some of the surfactant may remain in the impact modifier. The preferred surfactant for the emulsion polymerization process for preparing the impact modifiers of this invention are ionic surfactants comprising alkyl or alkylaryl sulfonates, alkyl or alkylaryl sulfates, alkyl or alkylaryl phosphates, or mixtures thereof. Examples of such surfactants include, but not limited thereto, sodium dodecyl benzene sulfonate, potassium octyl benzene sulfonate, sodium lauryl sulfate, sodium alkyl naphthyl sulfonates, calcium decyl benzene sulfonate, C8-C16 alkylated diphenylether sodium disulfonates, potassium hexyl phosphate, sodium decylphosphate, and mixtures thereof, and the like. Preferably the alkyl is an aliphatic hydrocarbon group of 6-30 carbon atoms and may be aryl substituted. The aryl groups are an organic radical derived from an aromatic hydrocarbon and may comprise 1 to 3 substituted phenyl rings. The preferred ionic surfactants are alkyl sulfonates.
The critical feature of the instant invention is that the impact modifier must be essentially free of alkali metal salts of fatty acids, alkali metal carbonates and other basic processing aids that would degrade a polycarbonate if residual amounts remained in the impact modifier. However, when employing the surfactants disclosed in the instant invention, residual quantities remaining in the impact modifier do not substantially degrade a polycarbonate when such impact modifiers are employed in a carbonate polymer composition.
Polycarbonates useful in preparing carbonate polymer compositions as disclosed in this invention are generally aromatic polycarbonates. Typically these are prepared by reacting a dihydric phenol with a carbonate precursor, such as phosgene, a haloformate or a carbonate ester and generally in the presence of an acid acceptor and a molecular weight regulator. Generally speaking, such carbonate polymers may be typified as possessing recurring structural units of the formula:
wherein A is a divalent aromatic radical of the dihydric phenol employed in the polymer reaction. The dihydric phenol which may be employed to provide such aromatic carbonate polymers are mononuclear or polynuclear aromatic compounds, containing as functional groups two hydroxy radicals, each of which maybe attached directly to a carbon atom of an aromatic nucleus. Typical dihydric phenols are: 2,2-bis(4-hydroxyphenyl)propane; hydroquinone; resorcinol; 2,2-bis(4-hydroxyphenyl)pentane; 2,4xe2x80x2-(dihydroxydiphenyl)methane; bis(2-hydroxyphenyl)methane; bis(4-hydroxyphenyl)methane; 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane; fluorenone bisphenol, 1,1-bis(4-hydroxyphenyl)ethane; 3,3-bis(4-hydroxyphenyl)pentane; 2,2xe2x80x2-dihydroxydiphenyl; 2,6-dihydroxynaphthalene; bis(4-hydroxydiphenyl)sulfone; bis(3,5-diethyl-4-hydroxyphenyl)sulfone; 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane; 2,2-bis(3,5-dimethy-4-hydroxyphenyl)propane; 2,4xe2x80x2-dihydroxydiphenyl sulfone; 5xe2x80x2-chloro-2,4xe2x80x2-dihydroxydiphenyl sulfone; 4,4xe2x80x2-dihydroxydiphenyl ether; 4,4xe2x80x2-dihydroxy-3,3xe2x80x2-dichlorodiphenyl ether, Spiro biidane bis phenol and the like.
These aromatic polycarbonates can be manufactured by known processes, such as, for example and as mentioned above, by reacting a dihydric phenol with a carbonate precursor, such as phosgene, in accordance with methods set forth in the literature including the melt polymerization process. Generally in the melt polymerization process, a diphenyl carbonate is reacted with a bisphenol.
The carbonate precursor employed in preparing the polycarbonate of this invention can be either carbonyl halide or a haloformate. The carbonyl halides which can be employed herein are, for example carbonyl bromide, carbonyl chloride, etc.; or mixtures thereof. The haloformates suitable for use herein include bishaloformates of dihydric phenols. (bischloroformates of bis phenol A, hydroquinone, etc.) or glycols (bishaloformates of ethylene glycol, neopentyl glycol, polyethylene glycol, etc.). While other carbonate precursors will occur to those skilled in the art, carbonyl chloride, also known as phosgene is preferred.
The reaction disclosed above is preferably known as an interfacial process or reaction between the dihydric compound and a carbonyl chloride such as phosgene. Another process for preparing the aromatic polycarbonate employed in this invention is the transesterification process which involves the transesterification of an aromatic dihydroxy compound and a diester carbonate. This process is known as the melt polymerization process. In the practice of this invention, the process of producing the aromatic polycarbonate is not critical. The critical feature of this invention is the composition of the aromatic carbonate polymer with the particular impact modifier disclosed herein. As used herein, aromatic carbonate polymer shall mean and include any of the aromatic polycarbonates, polyester carbonates or combinations thereof.
It is also possible to employ two or more different dihydric phenols or a copolymer of a dihydric phenol with a glycol or with a hydroxy- or acid-terminated polyester or with a dibasic acid or hydroxy acid in the event a carbonate copolymer or interpolymer rather than a homopolymer is desired for use in the preparation of the polycarbonate mixtures of the invention. Polyarylates and polyester-carbonate resins or their blends can also be employed. Branched polycarbonates are also useful and are well disclosed in the literature. Also, blends of linear polycarbonate and a branched polycarbonate can be utilized herein. Moreover, blends of any of the above materials may be employed in the practice of this invention to provide the aromatic polycarbonate component of the carbonate polymer composition.
In any event, the preferred aromatic polycarbonate for use in the practice in the present invention is a homopolymer, e.g., a homopolymer derived from 2,2-bis(4-hydroxyphenyl)propane (bisphenol-A) and phosgene, commercially available under the trademark designation LEXAN(copyright) Registered TM of General Electric Company.
The polycarbonates are preferably high molecular weight aromatic polycarbonate having an intrinsic viscosity, as determined in chloroform at 25xc2x0 C. of from about 0.3 to about 1.5 deciliters per gram (dl/gm), preferably from about 0.45 to about 1.0 dl/gm. These polycarbonates may be branched or unbranched and generally will have a weight average molecular weight of from about 10,000 to about 200,000, preferably from about 20,000 to about 100,000 as measured by gel permeation chromatography.
The branched polycarbonates may be prepared by adding a branching agent during polymerization. These branching agents are well known and may comprise polyfunctional organic compounds containing at least three functional groups which may by hydroxyl, carboxyl, carboxylic anhydride, haloformyl and mixtures thereof. Specific examples include trimellitic acid, trimellitic anhydride, trimellitic trichloride, tris-p-hydroxy phenyl ethane, isatin-bis-phenol, tris-phenol TC (1,3,5-tris((p-hydroxyphenyl)isopropyl)benzene),tris-phenol PA (4(4(1,1-bis(p-hydroxyphenyl)-ethyl)alpha, alpha-dimethyl benzyl)phenol), 4-chloroformyl phthalic anhydride, trimesic acid and benzophenone tetracarboxylic acid. The branching agent may be added at a level of about 0.05-2.0 weight percent.
All types of polycarbonates end groups are contemplated as being within the scope of the present invention with respect to the polycarbonate component of a carbonate polymer composition.
In the practice of this invention and as used herein, carbonate polymer compositions include polycarbonates and blends of polycarbonates polymers with polyesters, such as polyalkylene phthalates. A preferred blend is a composition of an aromatic polycarbonate and a polyalklylenephthalate (polyester) preferably a polyalkyleneterephthalate such as polybutyleneterephthalate (PBT), polyethyleneterephthalate (PET), or polypropyleneterephthalate (PPT) with PBT being most preferred.
Polyesters include those comprising structural units of the following formula:
wherein each R1 is independently a divalent aliphatic, alicyclic or aromatic hydrocarbon or polyoxyalkylene radical, or mixtures therof and each A1 is independently a divalent aliphatic, alicyclic or aromatic radical, or mixtures thereof. Examples of suitable polyesters containing the structure of the above formula are poly(alkylene dicarboxylates), liquid crystalline polyesters, and polyester copolymers. It is also possible to use a branched polyester in which a branching agent, for example, a glycol having three or more hydroxyl groups or a trifunctional or multifunctional carboxylic acid had been incorporated. Furthermore, it is sometime desirable to have various concentrations of acid and hydroxyl end groups on the polyester, depending on the ultimate end-use of the composition.
The R1 radical may be, for example, a C2-C10 alkylene radical, a C6-20 alicyclic radical, a C6-20 aromatic radical or a polyoxyalkylene radical in which the alkylene groups contain about 2-6 and preferably 2 or 4 carbon atoms. The A1 radical in the above formula is most often p- or m- phenylene, naphthalene, a cycloaliphatic or a mixture thereof. This preferred class of polyester includes the poly(alkylene terphthalates).
Examples of aromatic dicarboxylic acids represented by the dicarboxylated residue A1 are isophthalic or terphthalic acid, 1,2-di(p-carboxyphenyl)ethane, 4,4xe2x80x2-dicarboxydiphenyl ether, 4,4xe2x80x2bisbenzoic acid and mixtures thereof. Acids containing fused rings can also be present, such as in 1,4- 1,5- or 2,6-naphthalenedicarboxylic acids. The preferred dicarboxylic acids are terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, cyclohexane dicarboxylic acid or mixtures thereof.
The most preferred polyesters are poly(ethylene terephthalate) (xe2x80x9cPETxe2x80x9d), and poly(1,4-butylene terephthalate), (xe2x80x9cPBTxe2x80x9d), poly(ethylene naphthanoate) (xe2x80x9cPENxe2x80x9d), poly(butylene naphthanoate), (xe2x80x9cPBNxe2x80x9d) and (polypropylene terphthalate) (xe2x80x9cPPTxe2x80x9d), polycyclohexanedimethanol terephthalate (PCT) and mixtures thereof.
Also contemplated herein are the above polyesters with minor amount, e.g., from about 0.5 to about 10 percent by weight, of units derived from aliphatic acid and/or aliphatic polyols to make copolyesters.
Blends of an aromatic polycarbonate and a polyester comprise blends of about 10 to about 90 weight % of an aromatic polycarbonate and correspondingly about 90 to about 10 weight % of a polyalkylenephthalate. Preferably, the blend composition comprises about 30 to about 70 weight % of an aromatic polycarbonate and correspondingly, about 70 to about 30 weight % of a polyester. The weight % is based on the total weight of the polycarbonate and polyalkylenephthalate. The preferred polyalkylenephthalate is a polyalkyleneterephthalate and more particularly a polybutyleneterephthalate.
The rubbery impact modifiers that may be blended with PC maybe vinyl aromatic, alkylacrylate, methacrylate or vinylnitrile resins which comprise (a) rubber modified monovinylidene aromatic graft copolymer and/or (b) an ungrafted copolymer, and are generally prepared by emulsion graft polymerization of a mixture of a monovinylidene monomer and one or more comonomers in the presence of one or more rubbery polymeric substrates. Depending on the amount of rubber present, a separate matrix or continuous phase of ungrafted rigid (co) polymer may be simultaneously obtained along with the rubber modified monovinylidene graft polymer. Typically, the rubber modified resins comprise the rubber modified graft copolymer at a level of from 40 to 95 percent by weight based on the total weight of the resin, preferably from 50 to 85 percent by weight thereof, more particularly 75 to 85 percent by weight thereof. The compatibilizing, graft polymer is present at a level of from 60 to 5 percent by weight based on the total weight of the resin, preferably from 15 to 50 percent by weight thereof, and more preferably from 15 to 25 percent by weight thereof.
Monovinylidene aromatic monomers which may be employed include styrene, xcex1-methyl styrene, halostyrenes i.e. dibromostyrene, mono or di alkyl, alkoxy or hydroxy substituted groups on the nuclear ring of the monovinylidene aromatic monomer i.e. vinyltoluene, vinylxylene, butylstyrene, para-hydroxystyrene or methoxystyrene or mixtures thereof. The monovinylidenearomatic monomers utilized are generically described by the following formula:
wherein X is selected from the group consisting of hydrogen, alkyl groups of 1 to 5 carbon atoms, cycloalkyl, aryl, alkaryl, aralkyl, alkoxy, aryloxy, and halogens. R is selected from the group consisting of hydrogen, alkyl groups of 1 to 5 carbons atoms and halogens such as bromine and chlorine. Examples of substituted vinylaromatic compounds include styrene, 4-methylstyrene, 3,5-diethylstyrene, 4-n-propylstyrene, xcex1-methylstyrene, xcex1-methyl vinyltoluene, xcex1-chlorostyrene, xcex1-bromostyrene, dichlorostyrene, dibromostyrene, tetrachlorostyrene, mixtures thereof and the like. The preferred monovinylidene aromatic monomers used are styrene and/or xcex1-methylstryrene.
Comonomers which may be used with the monovinylidene aromatic monomer includes acrylonitrile, methacrylonitrile, C1 to C8 alkyl or aryl substituted acrylate, C1 to C8 alkyl, aryl or haloaryl substituted methacrylate, acrylic acid, methacrylic acid, itaconic acid, acrylamide, N-substituted acrylamide or methacrylamide, maleic anhydride, maleimide, N-alkyl, aryl or haloaryl substituted maleimide, glycidyl (meth)acrylates, hydroxy alkyl (meth)acrylates or mixtures thereof. The acrylonitrile, substituted acrylonitrile, or acrylic acid esters are described generically by the following formula:
wherein R is as previously defined and Y is selected from the group consisting of cyano and carbalkoxy groups wherein the alkoxy group of the carbalkoxy contains from one or about twelve carbon atoms. Examples of such monomers include acrylonitrile, ethacrylonitrile, methacrylonitrile, xcex1-chloroacrylonitrile, xcex1-bromoacrylonitrile, methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, propylacrylate, isopropyl acrylate and mixtures thereof. The preferred monomer is acrylonitrile and the preferred acrylic acid esters are ethyl acrylate and methyl methacrylate.
The rubber modified graft copolymer preferably comprises (i) the rubber substrate, and (ii) a rigid polymeric superstrate portion grafted to the rubber substrate. The rubber substrate is preferably present in the graft copolymer at a level of from 40 to 95 percent by weight based on the total weight of the graft copolymer, more preferably from 50 to 85 percent by weight thereof, and most preferably 75 to 85 percent by weight thereof.
Examples of rubber polymers for the substrate include: conjugated dienes, copolymers of a diene with styrene, acrylonitrile, methacrylonitrile or C1 to C12 alkyl acrylate which contain at least 50% (preferably at least 65%) by weight % conjugated dienes, polyisoprene or mixtures thereof; olefin rubbers i.e. ethylene propylene copolymers (EPR) or ethylene propylene non-conjugated diene copolymers (EPDM); silicone rubbers; or C1 to C8 alkyl acrylate homopolymers or copolymers with butadiene and/or styrene. The acrylic polymer may also contain up to 5% of one or more polyfunctional crosslinking agents such as alkylenediol di(meth)acrylates, alkylenetriol tri(meth)acrylates, polyester di(meth)acrylates, divinylbenzene, trivinylbenzene, butadiene, isoprene and optionally graftable monomers such as, triallyl cyanurate, triallyl isocyanurate, allyl (meth)acrylate, diallyl maleate, diallyl fumarate, diallyl adipate, triallyl esters of citric acid or mixtures of these agents.
The diene rubbers may preferably be polybutadiene, polyisoprene and copolymers of butadiene which are produced by aqueous radical emulsion polymerization. The acrylate rubbers may be cross-linked, particulate emulsion copolymers substantially of C1-C8 alkylacrylate, in particular C4-C6-alkylacrylate, optionally in admixture with up to 15% by weight of comonomers such as styrene, methylmethacrylate, butadiene, vinyl methyl ether or acrylonitrile and optionally up to 5% weight of a polyfunctional crosslinking comonomer, e.g. divinyl-benzene, glycol-bis-acrylates, bisacrylatmides, phosphoric acid triallylester, citric acid triallyl-ester, allylesters or acrylic acid or methacrylic acid, triallylcyanurate, triallylisocyanurate. Also suitable are mixtures of diene- and alkylacrylate rubbers and rubbers which have a so-called core/shell structure, e.g. a core of a diene or acrylate rubber and a shell of an acrylate or styrene acrylonitrile.
Specific conjugated diene monomers normally utilized in preparing the rubber substrate of the graft or core shell polymer are generically described by the following formula:
wherein X is selected from the group consisting of hydrogen, alkyl groups containing from one to five carbon atoms, chlorine or bromine. Examples of dienes that may be used are butadiene, isoprene, 1,3-heptadiene, methyl-1,3-pentadiene, 2,3-dimethylbutadiene, 2-ethyl-1,3-pentadiene 1,3- and 2,4-hexadienes, chloro and bromo substituted butadienes such as dichlorobutadiene, bromobutadiene, dibromobutadiene, mixtures thereof and the like. A preferred conjugated diene is 1,3 butadiene.
The substrate polymer, as mentioned, is preferably a conjugated diene polymer such as polybutadiene, polyisoprene, or a copolymer, such as butadiene-styrene, butadiene-acrylonitrile, or the like. The rubbery polymeric substrate portion has a glass transition temperature (Tg) is equal to or less than about 0xc2x0 C.
Mixtures of one or more rubbery polymers previously described for preparing the monvinylidene aromatic graft polymers, or mixtures of one or more rubber modified monovinylidene aromatic graft polymers disclosed herein may also be employed. Furthermore, the rubber may comprise either a block or random copolymer. The rubber particle size is not critical to this invention but maybe measured by simple light transmission methods or capillary hydrodynamic chromatography (CHDF) may be described as having an average particle size by weight of 0.05 to 1.2 microns, preferably 0.2 to 0.8 microns, for emulsion based polymerized rubber latices or 0.5 to 10 microns, preferably 0.6 to 1.5 microns, for mass polymerized rubber substrates which also have included grafted monomer occulsions. The rubber substrate is preferably a particulate, moderately cross-linked diene or alkyl acrylate rubber, and preferably has a gel content greater than 70%.
Preferred graft superstrates include copolymers of styrene and acrylonitrile, copolymers of xcex1-methylstyrene and acrylonitrile, methylmethacrylate polymers or copolymers. Specific examples of monovinylidene aromatic graft copolymers include but are not limited to the following: acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-butyl acrylate (ASA), methylmethacrylate-acrylonitrile-butadiene-styrene (MABS), acrylonitrile-ethylene-propylene-non-conjugated diene-styrene (AES). The most preferred are methacrylate butadiene styrene (MBS) and methylacrylate, butyl acrylate (acrylic rubber) such as graft copolymers or have a shell-core structure.
The ungrafted polymers (typically free of rubber) are resinous, thermoplastic polymers of styrene, xcex1-methylstyrene, styrenes substituted in the nucleus such as para-methylstyrene, methyl acrylate, methylmethacrylate, acrylonitrile, methacrylonitrile, maleic acid anhydride, N-substituted maleimide, vinyl acetate or mixtures thereof. Styrene/acrylonitrile copolymers, xcex1-methylstyrene/acrylonitrile copolymers, methylmethacrylate/acrylonitrile copolymers, polyaklylacrylates, polyacrylates or copolymers thereof are preferred.
The ungrafted rigid copolymers are known and may be prepared by radical polymerization, in particular by emulsion, suspension, solution or bulk polymerization. They preferably have number average molecular weights of from 20,000 to 200,000.
These rubber modified monovinylidene graft polymers may be polymerized either by mass, emulsion, suspension, solution or combined processes such as bulk-suspension, emulsion-bulk, bulk-solution or other techniques may be produced either by continuous, semibatch or batch processes, and are essentially free from alkali metal salts of fatty acids, alkali metal carbonates and other basic materials.
The instant invention is directed to a carbonate polymer composition comprising an aromatic carbonate polymer and an impact modifier wherein the impact modifier is free of basic materials such as alkali metal salts of fatty acids of C6-C30 carbon atoms, alkali metal carbonates and other basic materials such as amines or ammonium salts as disclosed previously. The impact modifier may be a shell-core structure having a rubbery core and thermoplastic shell or a graft rubber copolymer. The rubbery core is prepared by an emulsion polymerization process employing a surfactant selected from the group consisting of alkyl or alkylaryl sulfonates, alkyl or alkylaryl sulfates, alkyl or alkylaryl phosphates, substituted silicates and mixtures thereof as disclosed previously. The preferred surfactant is an alkly sulfonate having an alkyl group of C6-C16 carbon atoms and preferably C8-C12 carbon atoms.
In the practice of this invention, any impact modifier may be employed providing it is free of the alkali metal salts of fatty acids, alkali metal carbonates and other basic materials. Preferably, the impact modifier comprises a shell-core structure wherein the core is a rubbery material with a glass transition temperature (Tg) equal to or less than 0xc2x0 C. and include such rubbery material as butyl rubber acrylates, polyolefins, siloxanes, polybutadienes, polyisoprenes, styrene butadiene rubbers, mixtures thereof, and the like. The shell is a thermoplastic polymer that is readily wet by the PC. The shell may merely physically encapsulate the core, or the shell may be partially or essentially completely grafted to the core. More specifically, the shell comprises a vinylaromatic compound and/or a vinylcyanide acid or an alkyl (meth) acrylate.
Olefin-containing copolymers such as olefin acrylates and olefin diene terpolymers can additionally be used as impact modifiers in the present compositions. An example of an olefin acrylate copolymer impact modifier is ethylene ethylacrylate copolymer available from Union Carbide as DPD-6169. Other higher olefin monomers can be employed as copolymers with alkyl acrylates, for example, propylene and n-butyl acrylate. The olefin diene terpolymers are well known in the are and generally fall into the EPDM (ethylene propylene diene) family of terpolymers. Polyolefins such as polyethylene, polyethylene copolymers with alpha olefins are also of use in these compositions.
Additionally, styrene-containing polymers can also be used as impact modifiers. Examples of such polymers are styrene butadiene styrene (SBS), styrene ethylene butylene styrene (SEBS), and other high impact styrene-containing polymers (HIPS).
The emulsion polymerization process for preparing the impact modifier of this invention is not critical and is described and disclosed in various patents and literature of such companies as Rohm and Haas and General Electric Company. However, the critical feature of the instant invention is that the impact modifier must be essentially free of those emulsifiers set forth previously.
The carbonate polymer composition comprises in admixture a carbonate polymer and an impact modifier. The carbonate polymer may be a polycarbonate or a blend of a polycarbonate and a polyester as described previously. The composition comprises about 60 to about 99 weight % of a carbonate polymer and, correspondingly, about 40 to about 1 weight % of an impact modifier. Preferably the composition comprises about 75 to about 95 weight % and more particularly about 85 to about 95 weight % of a carbonate polymer and, correspondingly, about 25 to about 5 weight % and more particularly about 15 to about 5 weight % of an impact modifier. The weight % is based on the total weight of carbonate polymer and impact modifier.
In addition, this invention is also directed to an impact modifier which is essentially free of those emulsifiers as set forth above. The impact modifier preferably has a pH of about 3 to about 8 and preferably 4 to about 7.

Impact modified carbonnate polymer composition having improved resistance to degradation and improved thermal stability