Method for making gel including salt reduction step

Abstract

Methods for making formable polymers including elastomeric gels resulting in a formable polymer having air voids or pockets are disclosed. The methods can include forming a formable polymer around salt particles or other dissolvable particles, permitting the formable polymer to solidify, then reducing the salt or other dissolvable particles by use of water or a solvent or melting, leaving air pockets or voids in the formable polymer.

Description

BACKGROUND

[0002] In the past, if it was desired to have a gel that had voids or air pockets in it, the gel could be made by foaming or by injection molding it into its desired shape.

SUMMARY

[0003] Methods for making gel that has voids or air pockets in it are disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] FIGS. 1 and 2 depict gel that has been formed to have voids or air pockets according to disclosed methods.

DETAILED DESCRIPTION

[0005] Referring to FIG. 1, an example gel 101 is depicted that has been formed to have voids or air pockets 103 within the elastomer gel material 102 made according to disclosed methods. This example has been formed using large salt pellets about 10-20 mm in length. The methods disclosed herein can be used to make void-filled elastomer gels, such as the gels disclosed in detail below, or to make any type of void-filled thermoplastic or thermoset material, or any type of cross-linkable material. Referring to FIG. 2, another example gel 201 has been formed to have finer voids or air pockets 202 by using rock salt.

[0006] First, start with an elastomer gel, thermoplastic material, thermoset material or cross-linkable material. Second, cut or separate the material into distinct particles or pieces. Third, mix a quantity of discrete units of dissolvable substance such as rock salt with the particles. Fourth, agglomerate, press, heat, fuse, or bind the particles together with the discrete units to form a solid component of gel, thermoset material, etc. that includes the discrete units of dissolvable substance within. This step can be conducted in a mold if desired. The discrete units can be wet or lightly solvated before mixing with the particles if desired. Alternatively, the discrete units of dissolvable substance can be agglomerated, pressed, heated, fused, or bound first, and then the elastomer gel, thermoplastic material, thermoset material or cross-linkable material can be injected into the voids of the dissolvable substance. Next, reduce the discrete units of dissolvable substance such as by introducing water or a solvent or by increasing the temperature until the dissolvable substance melts out or is otherwise reduced. This is generically referred to as a salt-reducing step. The result is a solid unit of elastomer gel, thermoplastic material, thermoset material, or cross-linkable material formed with voids and air pockets in it to have a relatively coarse foamed appearance. Such a foam can be very soft, stretchable, strong and have high hand (supple). Such methods are very useful in achieving foam in materials that are difficult or impossible to foam by traditional methods. As an example of the above process: Pellets of elastomeric gel as described below is mixed with salt pellets such as Morton Salt Pellets for water softeners, sold by the Morton Salt Company and commonly available in grocery stores. The mixture is heated to 300 degrees F., which melts the elastomeric gel pellets but does not affect the salt pellets. The mixture of molten gel and salt pellets is pressed at 1,000 psi in a mold and cooled under pressure. The mold is opened and the resultant gel/salt mass is removed and placed in water. The water dissolves out most of the salt. The water is able to reach all the salt pellets because the earlier 1,000 psi pressure ensured that each salt pellet was touching another salt pellet, making channels from pellet to pellet as the water dissolves the salt. After the salt is dissolved, the water is allowed to escape or is squeezed out of the gel. The resultant gel is lighter weight and softer than would be a solid block of the same gel. It is also easier to elongate and has a better hand (is more supple). In another example with the same materials, the salt pellets are first wet with water and then placed into a mold and allowed to dry. The water on the surface of the pellets fuses the salt pellets at the contact points. The salt pellets are now fused into a single structure with the shape of the mold cavity. With for example an injection molder, molten gel is then driven by pressure into the voids of the salt structure and the gel is allowed to cool. The salt is removed as in the prior example and the result is the same. This method may provide better reliability in the water reaching all of the salt pellets in the case wherein the molten gel is of high viscosity.

[0007] Elastomeric gel as used herein shall mean any elastomeric gel as exemplified by gels of the several patents and patent applications to which priority is cited above, and others which may be known or become known at a later date. As an example, such gels may include combination of an elastomer and a plasticizer. The elastomer may be any appropriate elastomer, including but not limited to A-B-A triblock copolymers such as SEPS, SEBS, SEEPS and others.

[0008] KRATON® and SEPTON® are examples of trade names used to identify some A-B-A triblock copolymers that may be used to make elastomer gels. Suitable plasticizers for elastomer gels include oils such as mineral oils, resins, rosins and others. Other components may be used in the gel as well, such as antioxidants, colorants, bleed reducing additives, microspheres and other components. The elastomer gel or gelatinous elastomer can be made quite tacky by the addition of resins and other sticky or tacky plasticizers. The elastomer gel may be manufactured by solvent blending, melt blending or compounding under heat and pressure such as by use of a single screw or twin screw compounding machine or otherwise.

[0009] Example elastomeric gels that can be considered for discussion purposes herein include, in parts by weight:

EXAMPLE ELASTOMER GEL FORMULA
20 parts  Septon 4055 SEPS tri-block copolymer, available from
          Kuraray of Japan
60 parts  Duoprime 90 white paraffinic mineral oil available from
          Lyondell of Houston, Texas
0.3 parts blaze orange aluminum lake pigment available from Day-Glo
          Corporation of Twinsburg, Ohio
0.1 parts Irgannox 1076 antioxidant available from Ciba Geigy of
          Basel, Switzerland
ANOTHER EXAMPLE ELASTOMER GEL FORMULA
20 parts  Septon 4044 SEPS triblock copolymer, available from
          Kuraray of Japan
20 parts  Septon 4055 SEPS triblock copolymer, available from
          Kuraray of Japan
70 parts  Duoprime 90 white paraffinic mineral oil available from
          Lyondell of Houston, Texas
0.1 part  aluminum lake blue pigment
0.1 part  Irgannox 1076 antioxidant
A THIRD EXAMPLE ELASTOMER GEL FORMULA
40 parts  Septon 4055 SEPS triblock copolymer, available from
          Kuraray of Japan
120 parts Duoprime 90 white paraffinic mineral oil available from
          Lyondell of Houston, Texas
0.1 part  aluminum lake blue pigment
0.1 part  Irgannox 1076 antioxidant
A FOURTH EXAMPLE ELASTOMER GEL FORMULA
20 parts  Septon 4055 SEPS triblock copolymer, available from
          Kuraray of Japan
20 parts  Septon 4077 SEPS triblock copolymer, available from
          Kuraray of Japan
140 parts Duoprime 90 white paraffinic mineral oil available from
          Lyondell of Houston, Texas
0.1 part  aluminum lake blue pigment
0.1 part  Irgannox 1076 antioxidant

[0010] Elastomer gels used to make the devices may be of any desired softness or rigidity, but some examples will be in the durometer range of from less than 0 to about 50 on the Shore A scale.

[0011] The manufacture of a gelatinous elastomer can be as disclosed in the patents and patent applications to which priority is claimed and may include any of melt blending, solvent blending or compounding by use of heat and pressure such as by using a single screw or twin screw compounding machine, or otherwise.

[0012] Elastomer Component

[0013] Compositions of elastomer gels maybe low durometer (as defined below) thermoplastic elastomeric compounds and visco-elastomeric compounds which include an elastomeric block copolymer component and a plasticizer component.

[0014] The elastomer component may include a triblock polymer of the general configuration A-B-A, wherein the A represents a crystalline polymer such as a monoalkenylarene polymer, including but not limited to polystyrene and functionalized polystyrene, and the B is an elastomeric polymer such as polyethylene, polybutylene, poly(ethylene/butylene), hydrogenated poly(isoprene), hydrogenated poly(butadiene), hydrogenated poly(isoprene+butadiene), poly(ethylene/propylene) or hydrogenated poly(ethylene/butylene+ethylene/propylene), or others. The A components of the material link to each other to provide strength, while the B components provide elasticity. Polymers of greater molecular weight are achieved by combining many of the A components in the A portions of each A-B-A structure and combining many of the B components in the B portion of the A-B-A structure, along with the networking of the A-B-A molecules into large polymer networks.

[0015] An example elastomer for making the elastomer gel material is a very high to ultra high molecular weight elastomer and oil compound having an extremely high Brookfield Viscosity (hereinafter referred to as “solution viscosity”). Solution viscosity is generally indicative of molecular weight. “Solution viscosity” is defined as the viscosity of a solid when dissolved in toluene at 25-30 degrees C., measured in centipoises (cps). “Very high molecular weight” is defined herein in reference to elastomers having a solution viscosity, 20 weight percent solids in 80 weight percent toluene, the weight percentages being based upon the total weight of the solution, from greater than about 20,000 cps to about 50,000 cps. An “ultra high molecular weight elastomer” is defined herein as an elastomer having a solution viscosity, 20 weight percent solids in 80 weight percent toluene, of greater than about 50,000 cps. Ultra high molecular weight elastomers have a solution viscosity, 10 weight percent solids in 90 weight percent toluene, the weight percentages being based upon the total weight of the solution, of about 800 to about 30,000 cps and greater. The solution viscosities, in 80 weight percent toluene, of the A-B-A block copolymers useful in the elastomer component of the gel are substantially greater than 30,000 cps. The solution viscosities, in 90 weight percent toluene, of the A-B-A elastomers useful in the elastomer component of the gel are in the range of about 2,000 cps to about 20,000 cps. Thus, the elastomer component of the gel material may have a very high to ultra high molecular weight.

[0016] The elastomeric B portion of the A-B-A polymers has an exceptional affinity for most plasticizing agents, including but not limited to several types of oils, resins, and others. When the network of A-B-A molecules is denatured, plasticizers which have an affinity for the B block can readily associate with the B blocks. Upon renaturation of the network of A-B-A molecules, the plasticizer remains highly associated with the B portions, reducing or even eliminating plasticizer bleed from the material when compared with similar materials in the prior art, even at very high oil:elastomer ratios. The reason for this performance may be any of the plasticization theories explained above (i.e., lubricity theory, gel theory, mechanistic theory, and free volume theory).

[0017] The elastomer used may be an ultra high molecular weight polystyrene-hydrogenated poly(isoprene+butadiene)-polystyrene, such as those sold under the brand names SEPTON® 4044, SEPTON® 4055 and SEPTON® 4077 by Kuraray, an ultra high molecular weight polystyrene-hydrogenated polyisoprene-polystyrene such as the elastomers made by Kuraray and sold as SEPTON® 2005 and SEPTON® 2006, or an ultra high molecular weight polystyrene-hydrogenated polybutadiene-polystyrene, such as that sold as SEPTON 8006 by Kuraray. High to very high molecular weight polystyrene-hydrogenated poly(isoprene+butadiene)-polystyrene elastomers, such as that sold under the trade name SEPTON® 4033 by Kuraray, are also useful in some formulations of the gel material because they are easier to process than the ultra high molecular weight elastomers due to their effect on the melt viscosity of the material.

[0018] Following hydrogenation of the midblocks of each of SEPTON® 4033, SEPTON®) 4045, SEPTON® 4055, and SEPTON® 4077, less than about five percent of the double bonds remain. Thus, substantially all of the double bonds are removed from the midblock by hydrogenation.

[0019] SEPTON® 4055 has a very high molecular weight (approximately 300,00, as determined by Applicant's gel permeation chromatography testing). SEPTON® 4077 has a somewhat higher molecular weight, and SEPTON® 4045 has a somewhat lower molecular weight than SEPTON® 4055. Materials which include either SEPTON® 4045 or SEPTON® 4077 as the primary block copolymer typically have lower tensile strength than similar materials made with SEPTON® 4055.

[0020] Kuraray Co. Ltd. of Tokyo, Japan has stated that the solution viscosity of SEPTON® 4055, the most A-B-A triblock copolymer for use in gel material, 10% solids in 90% toluene at 25 degrees C., is about 5,800 cps. Kuraray also said that the solution viscosity of SEPTON 4055, 5% solids in 95% toluene at 25 degrees C., is about 90 cps. Although Kuraray has not provided a solution viscosity, 20% solids in 80% toluene at 25 degrees C., an extrapolation of the two data points given shows that such a solution viscosity would be about 400,000 cps.

[0021] Applicant confirmed Kuraray's data by having an independent laboratory, SGS U.S. Testing Company Inc. of Fairfield, N.J., test the solution viscosity of SEPTON® 4055. When SGS attempted to dissolve 20% solids in 80% toluene at 25 degrees C., the resulting material did not resemble a solution. Therefore, SGS determined the solution viscosity of SEPTON 4055 using 10% solids in 90% toluene at 25 degrees C., which resulted in a 3,040 cps solution.

[0022] Other materials with chemical and physical characteristics similar to those of SEPTON® 4055 include other A-B-A triblock copolymers which have a hydrogenated midblock polymer that is made up of at least about 30% isoprene monomers and at least about 30% butadiene monomers, the percentages being based on the total number of monomers that make up the midblock polymer. Similarly, other A-B-A triblock copolymers which have a hydrogenated midblock polymer that is made up of at least about 30% ethylene/propylene monomers and at least about 30% ethylene/butylene monomers, the percentages being based on the total number of monomers that make up the midblock polymer, are materials with chemical and physical characteristics similar to those of SEPTON®) 4055.

[0023] Mixtures of block copolymer elastomers are also useful as the elastomer component of some of the formulations. In such mixtures, each type of block copolymer contributes different properties to the material. For example, high strength triblock copolymer elastomers are desired to improve the tensile strength and durability of a material. However, some high strength triblock copolymers are very difficult to process with some plasticizers. Thus, in such a case, block copolymer elastomers which improve the processability of the materials are desirable.

[0024] In particular, the process of compounding SEPTON® 4055 with plasticizers may be improved via a lower melt viscosity by using a small amount of more flowable elastomer such as SEPTON® 8006, SEPTON® 2005, SEPTON® 2006, or SEPTON® 4033, to name only a few, without significantly changing the physical characteristics of the material.

[0025] In a second example of the usefulness of block copolymer elastomer mixtures in the gel materials, many block copolymers are not good compatibilizers. Other block copolymers readily form compatible mixtures, but have other undesirable properties. Thus, the use of small amount of elastomers which improve the uniformity with which a material mixes are desired. KRATON® G1701, manufactured by Shell Chemical Company of Houston, Tex., is one such elastomer that improves the uniformity with which the components of the gel material mix.

[0026] Many other elastomers, including but not limited to triblock copolymers and diblock copolymers are also useful in the elastomer gel. Applicant believes that elastomers having a significantly higher molecular weight than the ultra-high molecular weight elastomers useful in the elastomer gel material increase the softness thereof, but decrease the strength of the gel. Thus, high to ultra high molecular weight elastomers, as defined above, are desired for use in the gel material due to the strength of such elastomers when combined with a plasticizer.

[0027] Additives

[0028] Polarizable Plasticizer Bleed-Reducing Additives

[0029] Some of the elastomer gel materials described herein do not exhibit migration of plasticizers, even when placed against materials which readily exhibit a high degree of capillary action, such as paper, at room temperature. Gel materials with higher plasticizer to polymer ratios may exhibit migration (bleed) and a bleed reducing additive is helpful to address the bleed issue.

[0030] A plasticizer bleed-reducing additive that may be useful in the elastomer gel material includes hydrocarbon chains with readily polarizable groups thereon. Such polarizable groups include, without limitation, halogenated hydrocarbon groups, halogens, nitrites, and others. Applicant believes that the polarizability of such groups on the hydrocarbon molecule of the bleed-reducing additive have a tendency to form weak van der Waals bonding with the long hydrocarbon chains of the rubber portion of an elastomer and with the plasticizer molecules. Due to the great length of typical rubber polymers, several of the bleed-reducers will be attracted thereto, while fewer will be attracted to each plasticizer molecule. The bleed-reducing additives are believed to hold the plasticizer molecules and the elastomer molecules thereto, facilitating attraction between the elastomeric block and the plasticizer molecule. In other words, the bleed-reducing additives are believed to attract a plasticizer molecule at one polarizable site, while attracting an elastomeric block at another polarizable site, thus maintaining the association of the plasticizer molecules with the elastomer molecules, which inhibits exudation of the plasticizer molecules from the elastomer-plasticizer compound. Thus, each of the plasticizer molecules is attracted to an elastomeric block by means of a bleed-reducing additive.

[0031] The bleed-reducing additives may have a plurality of polarizable groups thereon, which facilitate bonding an additive molecule to a plurality of elastomer molecules and/or plasticizer molecules. It is believed that an additive molecule with more polarizable sites thereon will bond to more plasticizer molecules. Preferably, the additive molecules remain in a liquid or a solid state during processing of the gel material.

[0032] The bleed-reducing additives may be halogenated hydrocarbon additives such as those sold under the trade name DYNAMAR® PPA-791, DYNAMAR® PPA-790, DYNAMAR® FX-9613, and FLUORAD® FC 10 Fluorochemical Alcohol, each by 3M Company of St. Paul, Minn. Other additives are also useful to reduce plasticizer exudation from the gel material. Such additives include, without limitation, other halogenated hydrocarbons sold under the trade name FLUORAD®, including without limitation FC-129, FC-135, FC-430, FC-722, FC-724, FC-740, FX-8, FX-13, FX-14 and FX-189; halogentated hydrocarbons such as those sold under the trade name ZONY®, including without limitation FSN 100, FSO 100, PFBE, 8857A, BA-L, BA-N, TBC and FTS, each of which are manufactured by du Pont of Wilmington, Del.; halogenated hydrocarbons sold under the trade name EMCOL by Witco Corp of Houston, Tex., including without limitation 4500 and DOSS; other halogenated hydrocarbons sold by 3M under the trade name DYNAMAR®.; chlorinated polyethylene elastomer (CPE), distributed by Harwick, Inc. of Akron, Ohio; chlorinated paraffin wax, distributed by Harwick, Inc.; and others. The bleed reducing additives may be hydrocarbon resins, elastomeric diblock copolymers, polyisobutylene, butyl rubber, or transpolyoctenylene rubber (“tor rubber”).

[0033] Detackifiers

[0034] The elastomer gel may include a detackifier. Tack is not necessarily desired. However, some of the elastomer gel formulas impart tack to the media.

[0035] Soaps, detergents and other surfactants have detackifying abilities and are useful in the gel material. “Surfactants,” as defined herein, refers to soluble surface active agents which contain groups that have opposite polarity and solubilizing tendencies. Surfactants form a monolayer at interfaces between hydrophobic and hydrophilic phases; when not located at a phase interface, surfactants form micelles. Surfactants have detergency, foaming, wetting, emulsifying and dispersing properties. Sharp, D. W. A., DICTIONARY OF CHEMISTRY, 381-82 (Penguin, 1990). For example, coco diethanolamide, a common ingredient in shampoos, is useful in the gel material as a detackifying agent. Coco diethanolamide resists evaporation, is stable, relatively non-toxic, non-flammable and does not support microbial growth. Many different soap or detergent compositions could be used in the material as well.

[0036] Other detackifiers include glycerin, epoxidized soybean oil, dimethicone, tributyl phosphate, block copolymer polyether, hydrocarbon resins, polyisobutylene, butyl rubber ,diethylene glycol mono oleate, tetraethyleneglycol dimethyl ether, and silicone, to name only a few. Glycerine is available from a wide variety of sources. Witco Corp. of Greenwich, Conn. sells epoxidized soybean oil as DRAPEX® . Dimethicone is available from a variety of vendors, including GE Specialty Chemicals of Parkersburg, W. Va. under the trade name GE SF 96-350. C.P. Hall Co. of Chicago, III markets block copolymer polyether as PLURONIC L-61. C.P. Hall Co. also manufactures and-markets diethylene glycol mono oleate under the name Diglycol Oleate--Hallco CPH-I-SE. Other emulsifiers and dispersants are also useful in the gel material. Tetraethyleneglycol dimethyl ether is available under the trade name TETRAGLYME® from Ferro Corporation of Zachary, La. Applicant believes that TETRAGLYME® also reduces plasticizer exudation from the gel material.

[0037] Antioxidants

[0038] The elastomer gel material may also include additives such as an antioxidant. Antioxidants such as those sold under the trade names IRGANOX® 1010 and IRGAFOS® 168 by Ciba-Geigy Corp. of Tarrytown, N.Y. are useful by themselves or in combination with other antioxidants.

[0039] Antioxidants protect the gel materials against thermal degradation during processing, which requires or generates heat. In addition, antioxidants provide long term protection from free radicals. An antioxidant inhibits thermo-oxidative degradation of the compound or material to which it is added, providing long term resistance to polymer degradation.

[0040] Heat, light (in the form of high energy radiation), mechanical stress, catalyst residues, and reaction of a material with impurities all cause oxidation of the material. In the process of oxidation, highly reactive molecules known as free radicals are formed and react in the presence of oxygen to form peroxy free radicals, which further react with organic material (hydro-carbon molecules) to form hydroperoxides.

[0041] The two major classes of antioxidants are the primary antioxidants and the secondary antioxidants. Peroxy free radicals are more likely to react with primary antioxidants than with most other hydrocarbons. In the absence of a primary antioxidant, a peroxy free radical would break a hydrocarbon chain. Thus, primary antioxidants deactivate a peroxy free radical before it has a chance to attack and oxidize an organic material.

[0042] Most primary antioxidants are known as sterically hindered phenols. One example of sterically hindered phenol is marketed by Ciba-Geigy as IRGANOX® 1010, which has the chemical name 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid, 2,2-bis [[3-[3,5-bis(dimethylethyl)-4-hydroxyphenyl]-1 -oxopropoxy]methyl]1 ,3-propa nediyl ester. The FDA refers to IRGANOX® 1010 as tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnimate)]methane. Other hindered phenols are also useful as primary antioxidants in the material.

[0043] Similarly, secondary antioxidants react more rapidly with hydroperoxides than most other hydrocarbon molecules. Secondary antioxidants have been referred to as hydroperoxide decomposers. Thus, secondary antioxidants protect organic materials from oxidative degradation by hydroperoxides.

[0044] Commonly used secondary antioxidants include the chemical classes of phosphites/phosphonites and thioesters, many of which are useful in the gel material. The hydroperoxide decomposer can be a phosphite known as Tris(2,4-di-tert-butylphenyl)phosphite and marketed by Ciba-Geigy as IRGAFOS® 168.

[0045] Primary and secondary antioxidants form synergistic combinations to ward off attacks from both peroxy free radicals and hydroperoxides.

[0046] Other antioxidants, including but not limited to multi-functional antioxidants, are also useful in the material. Multifunctional antioxidants have the reactivity of both a primary and a secondary antioxidant. IRGANOX® 1520 D, manufactured by Ciba-Geigy is one example of a multifunctional antioxidant. Vitamin E antioxidants, such as that sold by Ciba-Geigy as IRGANOX® E17, are also useful in the gel material.

[0047] The elastomer gel material may include up to about three weight percent antioxidant, based on the weight of the elastomer component, when only one type of antioxidant is used. The material may include as little as 0.1 weight percent of an antioxidant, or no antioxidant at all. When a combination of antioxidants is used, each may comprise up to about three weight percent, based on the weight of the elastomer component. Additional antioxidants may be added for severe processing conditions involving excessive heat or long duration at a high temperature.

[0048] The use of excess antioxidants reduces or eliminates tack on the exterior surface of the gel material. Excess antioxidants appear to migrate to the exterior surface of the material following compounding of the material. Such apparent migration occurs over substantial periods of time, from hours to days or even longer.

[0049] Flame Retardants

[0050] Flame retardants may also be added to elastomer gel materials. Flame retardants include but are not limited to diatomaceous earth flame retardants sold as GREAT LAKES DE 83R and GREAT LAKES DE 79 by Great Lakes Filter, Division of Acme Mills Co. of Detroit, Mich. Most flame retardants that are useful in elastomeric materials are also useful in the gel material.

[0051] Chemical blowing agents, such as SAFOAMO® FP-40, manufactured by Reedy International Corporation of Keyport, N.J. and others are useful for making a gel medium that is self-extinguishing.

[0052] Colorants

[0053] Colorants may also be used in gel materials. Any colorant which is compatible with elastomeric materials may be used. Aluminum lake colorants such as those manufactured by Warner Jenkinson Corp. of St. Louis, Mo. Are available. Pigments manufactured by Day Glo Color Corp. of Cleveland, Ohio; Lamp Black, such as that sold by Spectrum Chemical Manufacturing Corp. of Gardena, Calif.; and Titanium Dioxide (white) are also available. By using these colorants, the gel material takes on intense shades of colors, including but not limited to pink, red, orange, yellow, green, blue, violet, brown, flesh, white and black.

[0054] Paint

[0055] The elastomer gel may also be painted.

[0056] Other Additives

[0057] Melt temperature modifiers useful in the gel include cross-linking agents, hydrocarbon resins, diblock copolymers of the general configuration A-B and triblock copolymers of the general configuration A-B-A wherein the end block A polymers include functionalized styrene monomers, and others.

[0058] Melt viscosity modifiers that tend to reduce the melt viscosity of the pre-compounded component mixture of the medium include hydrocarbon resins, transpolyoctenylene rubber, castor oil, linseed oil, non-ultra high molecular weight thermoplastic rubbers, surfactants, dispersants, emulsifiers, and others.

[0059] Melt viscosity modifiers that tend to increase the melt viscosity of the pre-compounded component mixture of the gel material include hydrocarbon resins, butyl rubber, polyisobutylene, additional triblock copolymers having the general configuration A-B-A and a molecular weight greater than that of each of the block copolymers in the elastomeric block copolymer component of the material, particulate fillers, microspheres, butadiene rubber, ethylene/propylene rubber, ethylene/butylene rubber, and others.

[0060] Tensile strength modifiers which tend to increase the tensile strength of the gel material for use in the gel material include mid block B-associating hydrocarbon resins, non-end-block solvating hydrocarbon resins which associate with the end blocks, particulate reinforcers, and others.

[0061] Shrinkage inhibitors, which tend to reduce shrinkage of the gel material following compounding, that are useful in the material include hydrocarbon resins, particulate fillers, microspheres, transpolyoctenylene rubber, and others.

[0062] Microspheres

[0063] Microspheres may also be added to the gel material. The gel material may contain up to about 90% microspheres, by volume. In one microsphere-containing formulation of the gel material, microspheres make up at least about 30% of the total volume of the material. A second microsphere-containing formulation of the gel material includes at least about 50% microspheres, by volume.

[0064] Different types of microspheres contribute various properties to the material. For example, hollow acrylic microspheres, such as those marketed under the brand name MICROPEARL®, and generally in the 20 to 200 micron size range, by Matsumoto Yushi-Seiyaku Co., Ltd. of Osaka, Japan, lower the specific gravity of the material. In other formulations of the gel, the microspheres may be unexpanded DU(091-80), which expand during processing of the gel material, or pre-expanded DE (091-80) acrylic microspheres from Expancel Inc. of Duluth, Ga.

[0065] In formulations of the material which include hollow acrylic microspheres, the microspheres have substantially instantaneous rebound when subjected to a compression force which compresses the microspheres to a thickness of up to about 50% of their original diameter or less.

[0066] Hollow microspheres also decrease the specific gravity of the gel material by creating gas pockets therein. When a gel material includes microspheres, the microspheres must be dispersed, on average, at a distance of about one-and-ahalf (1.5) times the average microsphere diameter or a lesser distance from one another in order to achieve a specific gravity of less than about 0.50. Other formulations of the gel material have specific gravities of less than about 0.65, less than about 0.45, and less than about 0.25.

[0067] MICROPEARL® and EXPANCEL® acrylic microspheres are because of their highly flexible nature, as explained above, which tend to not restrict deformation of the thermoplastic elastomer. Glass, ceramic, and other types of microspheres may also be used in the thermoplastic gel material.

[0068] Plasticizer Component

[0069] As explained above, plasticizers allow the midblocks of a network of triblock copolymer molecules to move past one another. Thus, Applicant believes that plasticizers, when trapped within the three dimensional web of triblock copolymer molecules, facilitate the disentanglement and elongation of the elastomeric midblocks as a load is placed on the network. Similarly, Applicant believes that plasticizers facilitate recontraction of the elastomeric midblocks following release of the load. The plasticizer component of the gel may include oil, resin, a mixture of oils, a mixture of resins, other lubricating materials, or any combination of the foregoing.

[0070] Oils

[0071] The plasticizer component of the gel material may include a commercially available oil or mixture of oils. The plasticizer component may include other plasticizing agents, such as liquid oligomers and others, as well. Both naturally derived and synthetic oils are useful in the gel material. The oils may have a viscosity of about 70 SUS to about 500 SUS at about 100 degrees F. Paraffinic white mineral oils having a viscosity in the range of about 90 SUS to about 200 SUS at about 100 degrees F. may be used

[0072] One embodiment of a plasticizer component of the gel includes paraffinic white mineral oils, such as those having the brand name DUOPRIME®, by Lyondell Lubricants of Houston, Tex., and the oils sold under the brand name TUFFLO® by Witco Corporation of Petrolia, Pa. For example, the plasticizer component of the gel may include paraffinic white mineral oil such as that sold under the trade name LP-150® by Witco.

[0073] Paraffinic white mineral oils having an average viscosity of about 90 SUS, such as DUOPRIME® 90, are used in other embodiments of the plasticizer component. Applicant has found that DUOPRIME® 90 and oils with similar physical properties can be used to impart the greatest strength to the gel material.

[0074] Other oils are also useful as plasticizers in compounding the gel material. Examples of representative commercially available oils include processing oils such as paraffinic and naphthenic petroleum oils, highly refined aromatic-free or low aromaticity paraffinic and naphthenic food and technical grade white petroleum mineral oils, and synthetic liquid oligomers of polybutene, polypropene, polyterpene, etc., and others. The synthetic series process oils are oligomers which are permanently fluid liquid non-olefins, isoparaffins or paraffins. Many such oils are known and commercially available. Examples of representative commercially available oils include Amoco.RTM. polybutenes, hydrogenated polybutenes and polybutenes with epoxide functionality at one end of the polybutene polymer. Examples of various commercially available oils include: Bayol, Bernol, American, Blandol, Drakeol, Ervol, Gloria, Kaydol, Litetek, Marcol, Parol, Peneteck, Primol, Protol, Sontex, and the like.

[0075] Resins

[0076] Resins useful in the plasticizer component include, but are not limited to, hydrocarbon-derived and rosin-derived resins having a ring and ball softening point of up to about 150 degrees C., or from about 0 degrees C. to about 25 degrees C., and a weight average molecular weight of at least about 300.

[0077] Resins or resin mixtures which are highly viscous flowable liquids at room temperature (about 23 degrees C.) may be used. Plasticizers which are fluid at room temperature impart softness to the gel material. Resins which are not flowable liquids at room temperature are also useful in the material.

[0078] Some resins used have a ring and ball softening point of about 18 degrees C.; melt viscosities of about 10 poises (ps) at about 61 degrees C., about 100 ps at about 42 degrees C. and about 1,000 ps at about 32.degrees C. One such resin is marketed as REGALREZ® 1018 by Hercules Incorporated of Wilmington, Del. Variations of REGALREZ® 1018 which are useful in the material have viscosities including, but not limited to, 1025 stokes, 1018 stokes, 745 stokes, 11 4 stokes, and others.

[0079] Room temperature flowable resins that are derived from poly-.beta.-pinene and have softenening points similar to that of REGALREZ® 1018 are also useful in the plasticizer component of the medium. One such resin, sold as PICCOLYTE® S25 by Hercules Incorporated, has a softening point of about 25 degrees C.; melt viscosities of about 10 ps at about 80 degrees C., about 100 ps at about 56 degrees C. and about 1,000 ps at about 41 degrees C.; a MMAP value of about 88 degrees C.; a DACP value of about 45 degrees C.; an OMSCP value of less than about −50.degrees C. Other PICCOLYTE® resins may also be used in the gel material.

[0080] Another room temperature flowable resin which is useful in the plasticizer component of the material is marketed as ADTAC® LV by Hercules Incorporated. That resin has a ring and ball softening point of about 5 degrees C.; melt viscosities of about 10 ps at about 62 degrees C., about 100 ps at about 36 degrees C. and about 1,000 ps at about 20 degrees C.; a MMAP value of about 93 degrees C.; a DACP value of about 44 degrees C.; an OMSCP value of less than about −40 degrees C.

[0081] Resins such as the liquid aliphatic C-5 petroleum hydrocarbon resin sold as WINGTACK® 10 by the Goodyear Tire & Rubber Company of Akron, Ohio and other WINGTACK® resins are also useful in the gel material. WINGTACK® 10 has a ring and ball softening point of about 10 degrees C.; a Brookfield Viscosity of about 30,000 cps at about 25 degrees C.; melt viscosities of about 10 ps at about 53 degrees C. and about 100 ps at about 34 degrees C.; a 1:1 polyethylene-to-resin ratio cloud point of about 89 degrees C.; a 1:1 microcrystalline wax-to-resin ratio cloud point of about 77 degrees C.; and a 1:1 paraffin wax-to-resin ratio cloud point of about 64 degrees C.

[0082] Resins that are not readily flowable at room temperature (i.e., are solid, semi-solid, or have an extremely high viscosity) or that are solid at room temperature are also useful in the gel material. One such solid resin is an aliphatic C-5 petroleum hydrocarbon resin having a ring and ball softening point of about 98 degrees C.; melt viscosities of about 100 ps at about 156 degrees C. and about 1000 ps at about 109 degrees C.; a 1:1 polyethylene-to-resin ratio cloud point of about 90 degrees C.; a 1:1 microcrystalline wax-to-resin ratio cloud point of about 77 degrees C.; and a 1:1 paraffin wax-to-resin ratio cloud point of about 64 degrees C. Such a resin is available as WINGTACK® 95 and is manufactured by Goodyear Chemical Co.

[0083] Polyisobutylene polymers are an example of resins which are not readily flowable at room temperature and that are useful in the gel material. One such resin, sold as VISTANEX® LM-MS by Exxon Chemical Company of Houston, Tex., has a Tg of −60.degrees C., a Brookfield Viscosity of about 250 cps to about 350 cps at about 350 degrees F., a Flory molecular weight in the range of about 42,600 to about 46,100, and a Staudinger molecular weight in the range of about 10,400 to about 10,900. The Flory and Staudinger methods for determining molecular weight are based on the intrinsic viscosity of a material dissolved in diisobutylene at 20 degrees C.

[0084] Glycerol esters of polymerized rosin are also useful as plasticizers in the gel material. One such ester, manufactured and sold by Hercules Incorporated as HERCULES® Ester Gum 10D Synthetic Resin, has a softening point of about 116 degrees C.

[0085] Many other resins are also suitable for use in the gel material. In general, plasticizing resins are those which are compatible with the B block of the elastomer used in the material, and non-compatible with the A blocks.

[0086] In some formulations, tacky materials may be desirable. In such formulations, the plasticizer component of the gel material may include about 20 weight percent or more, about 40 weight percent or more, about 60 weight percent or more, or up to about 100 weight percent, based upon the weight of the plasticizer component, of a tackifier or tackifier mixture.

[0087] Plasticizer Mixtures

[0088] The use of plasticizer mixtures in the plasticizer component of the gel material is useful for tailoring the physical characteristics of the gel material. For example, characteristics such as durometer, tack, tensile strength, elongation, melt flow and others may be modified by combining various plasticizers.

[0089] For example, a plasticizer mixture which includes at least about 37.5 weight percent of a paraffinic white mineral oil having physical characteristics similar to those of LP-150 (a viscosity of about 150 SUS at about 100 degrees F., a viscosity of about 30 centistokes (cSt) at about 40 degrees C., and maximum pour point of about −35 degrees F.) and up to about 62.5 weight percent of a resin having physical characteristics similar to those of REGALREZ® 1018 (such as a softening point of about 20 degrees C.; a MMAP value of about 70 degrees C.; a DACP value of about 15 degrees C.; an OMSCP value of less than about −40 degrees C.; all weight percentages being based upon the total weight of the plasticizer mixture, could be used in a gel. When compared to a material plasticized with the same amount of an oil such as LP-150, the material which includes the plasticizer mixture has decreased oil bleed and increased tack.

[0090] When resin is included with oil in a plasticizer mixture of the gel the material exhibits reduced oil bleed. For example, a formulation of the material which includes a plasticizing component which has about three parts plasticizing oil (such as LP-150), and about five parts plasticizing resin (such as REGALREZ® 1018) exhibits infinitesimal oil bleed at room temperature, if any, even when placed against materials with high capillary action, such as paper.

[0091] The plasticizer:block copolymer elastomer ratio, by total combined weight of the plasticizer component and the block copolymer elastomer component in some formulations ranges from as low as about 1:1 or less to higher than about 25:1. In applications where plasticizer bleed is acceptable, the ratio may as high as about 100:1 or more. Plasticizer:block copolymer ratios in the range of about 2.5:1 to about 8:1 may be more common. A ratio such as 5:1 provides the desired amounts of rigidity, elasticity and strength for many typical applications. A plasticizer to block copolymer elastomer ratio of 2.5:1 has a high amount of strength and elongation.

[0092] Compounding Methods

[0093] Compounding may be carried out by melt blending, solvent blending, or compounding under heat and pressure such as by use of a single screw or twin screw compounding machine.

[0094] While the devices, materials and methods have been described and illustrated in conjunction with a number of specific examples, those skilled in the art will appreciate that variations and modifications may be made without departing from the principles herein illustrated, described, and claimed. The present invention, as defined by the appended claims, may be embodied in other specific forms without departing from its spirit or essential characteristics. The configurations of lights described herein are to be considered in all respects as only illustrative, and not restrictive. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A method for making a course foamed material comprising the steps of: selecting a material to be foamed selected from the group consisting of elastomer gels, thermoplastic materials, thermoset materials and cross-linkable materials, separating the material to be foamed into distinct particles, mixing a quantity of discrete units of dissolvable substance with the particles, agglomerating the particles and the discrete units together to form a generally solid component that includes discrete units of dissolvable substance within, introducing a solvent to the solid component, reducing the discrete units of dissolvable substance by use of said solvent to leave voids in said solid component so that solid component has the appearance of a course foam.

2. A method as recited in claim 1 wherein said agglomeration step includes a process selected from the group consisting of pressing, heating, fusing and binding said particles together.

3. A method as recited in claim 1 wherein said agglomeration step is conducted in a mold.

4. A method as recited in claim 1 wherein at least some of said discrete units of dissolvable substance are salt.

5. A method as recited in claim 1 wherein at least some of said discrete units of dissolvable particles are water soluble.

6. A method as recited in claim 1 wherein said solvent is water.

7. A method as recited in claim 1 wherein at least some of said discrete units of dissolvable particles are at least partially solvated prior to said agglomerating step.

8. A method as recited in claim 1 wherein said foam is soft, stretchable, strong and supple.

9. A method for making a course foamed material comprising the steps of: selecting an elastomer gel material to be foamed wherein said elastomer gel includes: an elastomer, and a plasticizer, separating the material to be foamed into distinct particles, mixing a quantity of discrete units of dissolvable substance with the particles, agglomerating the particles and the discrete units together to form a generally solid component that includes discrete units of dissolvable substance within, introducing a solvent to the solid component, reducing the discrete units of dissolvable substance by use of said solvent to leave voids in said solid component so that solid component has the appearance of a course foam; wherein said foam is soft, stretchable, strong and supple.

10. A method as recited in claim 1 wherein said agglomeration step includes a process selected from the group consisting of pressing, heating, fusing and binding said particles together; and wherein said agglomeration step is conducted in a mold.

11. A method as recited in claim 1 wherein at least some of said discrete units of dissolvable substance are salt; and wherein said solvent is water.

12. A method as recited in claim 9 wherein said elastomer is an A-B-A triblock copolymer.

13. A method as recited in claim 12 wherein said A-B-A triblock copolymer is selected from the group consisting of SEPS, SEBS and SEEPS.

14. A method as recited in claim 9 wherein said elastomer gel has a hardness in the durometer range of from less than 0 to about 50 on the Shore A scale.

15. A method as recited in claim 9 wherein said elastomer gel is substantially solid and non-flowable at room temperature.

16. A method for making a course foamed material comprising the steps of: selecting a elastomer gel material to be foamed wherein said elastomer gel includes: an elastomer, said elastomer being an A-B-A triblock copolymer, said A-B-A triblock copolymer being selected from the group consisting of SEPS, SEBS and SEEPS, and a plasticizer, said plasticizer being selected from the group consisting of resin, rosin, oil and combinations thereof, separating the material to be foamed into distinct particles, mixing a quantity of discrete units of dissolvable substance with the particles, agglomerating the particles and the discrete units together to form a generally solid component that includes discrete units of dissolvable substance within, introducing a solvent to the solid component, reducing the discrete units of dissolvable substance by use of said solvent to leave voids in said solid component so that solid component has the appearance of a course foam; wherein said foam is soft, stretchable, strong and supple.

17. A method as recited in claim 16 wherein said elastomer gel has a hardness in the durometer range of from less than 0 to about 50 on the Shore A scale.

18. A method as recited in claim 16 wherein said elastomer gel is substantially solid and non-flowable at room temperature.

19. A method for making a course foamed material comprising the steps of: accessing particles of a material to be foamed, mixing a quantity of discrete units of dissolvable substance with the particles, agglomerating the particles and the discrete units together to form a generally solid component that includes discrete units of dissolvable substance within, introducing a solvent to the solid component, and reducing the discrete units of dissolvable substance by use of said solvent to leave voids in said solid component so that solid component has the appearance of a course foam.

20. A method for making a course foamed material comprising the steps of: selecting a material to be foamed selected from the group consisting of elastomer gels, thermoplastic materials, thermoset materials and cross-linkable materials, selecting a quantity of discrete units of dissolvable substance with the particles, agglomerating the discrete units of dissolvable particles together to form a generally solid component with interstitial spaces, causing molten material to be foamed into said interstitial spaces and permitting said molten material to solidify, introducing a solvent to the solid component, reducing the discrete units of dissolvable substance by use of said solvent to leave voids in said solid component so that solid component has the appearance of a course foam made from said material to be foamed.

21. A method as recited in claim 20 wherein said agglomeration step includes a process selected from the group consisting of pressing, heating, fusing and binding.

22. A method as recited in claim 20 wherein said agglomeration step is conducted in a mold.

23. A method as recited in claim 20 wherein at least some of said discrete units of dissolvable substance are salt.

24. A method as recited in claim 20 wherein at least some of said discrete units of dissolvable particles are water soluble.

25. A method as recited in claim 20 wherein said solvent is water.

26. A method as recited in claim 20 wherein at least some of said discrete units of dissolvable particles are at least partially solvated prior to said agglomerating step.

27. A method as recited in claim 1 wherein said foam is soft, stretchable, strong and supple.

28. A method for making a course foamed material comprising the steps of: selecting an elastomer gel material to be foamed wherein said elastomer gel includes: an elastomer, and a plasticizer, selecting discrete units of dissolvable substance, agglomerating the discrete units together to form a generally solid component with interstitial spaces, causing said elastomer gel to be present in said interstitial spaces, introducing a solvent to the solid component, reducing the discrete units of dissolvable substance by use of said solvent to leave voids in said solid component so that solid component has the appearance of a course foam of elastomer gel; wherein said foam is soft, stretchable, strong and supple.

29. A method as recited in claim 29 wherein said agglomeration step includes a process selected from the group consisting of pressing, heating, fusing and binding; and wherein said agglomeration step is conducted in a mold.

30. A method as recited in claim 29 wherein at least some of said discrete units of dissolvable substance are salt; and wherein said solvent is water.

31. A method as recited in claim 28 wherein said elastomer is an A-B-A triblock copolymer.

32. A method as recited in claim 31 wherein said A-B-A triblock copolymer is selected from the group consisting of SEPS, SEBS and SEEPS.

33. A method as recited in claim 32 wherein said elastomer gel is substantially solid and non-flowable at room temperature.

34. A method for making a course foamed material comprising the steps of: selecting a elastomer gel material to be foamed, wherein said elastomer gel includes: an elastomer, said elastomer being an A-B-A triblock copolymer, said A-B-A triblock copolymer being selected from the group consisting of SEPS, SEBS and SEEPS, and a plasticizer, said plasticizer being selected from the group consisting of resin, rosin, oil and combinations thereof, selecting a quantity of discrete units of dissolvable substance, agglomerating the discrete units together to form a generally solid component that includes interstitial spaces, causing said elastomer gel to be present in said interstitial spaces, introducing a solvent to the solid component, reducing the discrete units of dissolvable substance by use of said solvent to leave voids in said solid component so that the solid component has the appearance of a course foam of elastomer gel; wherein said foam elastomer gel is soft, stretchable, strong and supple.

35. A method as recited in claim 34 wherein said elastomer gel is substantially solid and non-flowable at room temperature.

36. A method for making a course foamed material comprising the steps of: accessing a material to be foamed, accessing a quantity of discrete units of dissolvable substance, agglomerating said discrete units into a solid component with interstitial spaces therein, introducing said material to be foamed into said interstitial spaces, introducing a solvent to the solid component, and reducing the discrete units of dissolvable substance by use of said solvent to leave voids in said solid component so that solid component has the appearance of a course foam.