Abstract: A foamed, non-crosslinked resin particle having a bulk density of not greater than 0.045 g/cm.sup.3 and an average cell diameter of at least 200 .mu.m. The non-crosslinked resin includes a polypropylene resin to which a vinyl comonomer is graft-polymerized in such an amount that the weight ratio of the polypropylene resin to the grafted polymer of the vinyl comonomer is in the range of 97:3 to 65:35. The foamed resin particles are produced by grafting a vinyl comonomer to polypropylene resin particles at a temperature of less than 90.degree. C. in the presence of a specific radical polymerization initiator to obtain modified polypropylene resin particles and, then, expanding the modified polypropylene resin particles. The initiator used requires a temperature of not higher than 70.degree. C. for obtaining a half life of 10 hours.

Abstract: The present invention relates to a process for preparing a polymer dispersion foam L, where:a) a mixture M which comprises at least one conjugated diene monomer A and at least one ethylenically unsaturated comonomer B is polymerized by free-radical aqueous emulsion polymerization in the presence of at least one emulsifier to give a fine polymer dispersion P,b) the fine polymer dispersion P is pressure-agglomerated to give a coarse polymer dispersion G,c) the polymer dispersion G is concentrated, if desired, and is mixed, if desired, with a reinforcer dispersion H, andd) the dispersion from c) is foamed to give a polymer dispersion foam L,which comprises adjusting the average particle size and the particle size distribution of G by varying a parameter selected from:I) the solids content of P,II) the agglomeration temperature in step b),III) the agglomeration pressure in step b),IV) the content of comonomer B in the mixture M,V) the concentration of the emulsifier in P,VI) the agglomeration throughput,to polyme

Abstract: The present invention relates to a porous crosslinked hydrophilic polymeric material having cavities joined by interconnecting pores wherein at least some of the cavities at the interior of the material communicate with the surface of the material. The present invention also relates to a process for producing the polymeric material. This process involves combining a hydrophilic monomer phase with an oil discontinuous phase to form an emulsion, and polymerizing the emulsion. The emulsion can be a high internal phase emulsion (i.e., a "HIPE"). The polymeric material can be produced in a variety of forms. In one embodiment the emulsion is suspended in an oil suspension medium, and emulsion droplets are polymerized to produce polymeric microbeads.

Abstract: In a process for producing preferably graphite-containing, expandable styrene polymers by polymerization of styrene in aqueous suspension in the presence of two peroxides which decompose at different temperatures, the peroxide which decomposes at the higher temperature is di-tert-amyl peroxide.

Abstract: Provided is a method of preparing a light-weight and inexpensive void type plastic pigment having enhanced hiding power and whiteness relative to inorganic pigments such as titanium oxide or organic pigments such as conventional styrene polymeric plastic pigments by regulating the content of each monomer in the sheath polymerization after core polymerization and controlling the glass transition temperature of the first sheath which is the shell obtained by initial polymerization less than that of the core by 70 to 120.degree. C., thus increasing the difference of refractive index between the polymeric matrices.

Abstract: The invention relates to a composite foam comprising from 10 to 90% by volume of SiO.sub.2 aerogel particles and from 90 to 10% by volume of a foam, preferably a polyurethane and/or polyolefin foam, a process for its preparation and its use.

Abstract: Disclosed herein is an molded article of foamed and expanded beads of a propylene resin, which is obtained by heating and molding the foamed beads of the propylene resin, wherein the apparent density of the molded article is 0.11 to 0.45 g/cm.sup.3, a value obtained by dividing its maximum bending strength (kgf/cm.sup.2) determined in accordance with JIS K 7221 by the apparent density (g/cm.sup.3) is at least 160 (kgf/cm.sup.2)/(g/cm.sup.3), and the average number of cells at its section is within a range of 5 to 100 cells/mm.sup.2.

Abstract: A foamed styrene resin material has a density .rho. of 0.02 to 0.008 and a melt tension of the styrene resin of 5 to 40 gf. The relation between an average cell diameter d (.mu.m) and the density .rho. is given by the expression: ##EQU1## and a relation between a thermal conductivity .lambda. (kcal/m.multidot.h.multidot..degree. C.) and the density .rho. given by the expression: ##EQU2## Accordingly, the foamed styrene resin material has a low thermal conductivity and excellent insulating property in spite of a low density (high expansion ratio foam) thereof.

Abstract: The present invention provides pre-expanded noncrosslinked polyethylene resin beads which are made of a mixed resin, as a base resin, comprising a high-pressure-process low-density polyethylene, a linear low-density polyethylene, and a linear high-density polyethylene and, when analyzed with a differential scanning calorimeter (DSC), give a fusion endothermic curve which is a mountain-shaped curve having a single peak and in which, when the peak point of the mountain-shaped curve is referred to as A, the point of intersection of the perpendicular line drawn to the temperature axis from A and the base line of the fusion endothermic curve is referred to as B, and the two points at which the straight line drawn through the point C interiorly dividing segment AB in the perpendicular line in a ratio of 9:1 and parallel to the temperature axis intersects the fusion endothermic curve are referred to as D and E, then that temperature width of the mountain-shaped curve part which is the length of segment DE is 15.

Abstract: Methods for impregnating polymer beads comprise providing polymer beads in an impregnation chamber at a temperature from about 150.degree. F. to about 200.degree. F. and a pressure of from about 25 psig to about 100 psig, and simultaneously fluidising the polymer beads in the impregnation chamber with an impregnating gas. The gas is delivered to the chamber at a rate sufficient to cause individual polymer beads to be fluidised and for a time sufficient to impregnate the gas in the polymer beads. The apparatus adapted for such methods includes a heater, a compressor and a plurality of vents for supplying a gas to the impregnating chamber to fluidise polymer beads contained therein simultaneously with the heating and pressurising of the beads.

Abstract: Unsupported pressure sensitive adhesive (PSA) films of tacky, polymeric microspheres are provided. The opposite major surfaces of the film provide different levels of peel adhesion, allowing for removability without substrate damage. In addition, the PSA films provide high shear strength and good tensile properties.

Abstract: Polyolefinic foam beads which can be processed over a wide temperature range to give molded articles where a ratio of the areas of low-temperature peak and high-temperature peak in the DSC curve during the first heating has a value of not more than 3, and where the heat of fusion of the secondary crystals is greater than 10 J/g.

Abstract: The invention relates to a process for producing loose fill in the form of spherical segments having a convex outer surface and a concave inner surface, and the granules formed. It is provided that starch granules are fed into a drum, and that in the drum, a nucleating agent is drum-coated onto the starch granules, and that the starch granules drum-coated with the nucleating agent are fed to an extruder, in which the starch granules are converted from their solid state into a viscous-liquid state. A starch foam created, by furnishing heat, in the extruder by the decomposition of the nucleating agent emerges from a forming opening of the extruder with a curved surface as a result of the difference in speed prevailing over the cross section of the composition, and that the skein of starch emerging from this forming opening is cut off directly at the forming opening, before any considerable expansion has taken place. The thus-created starch particles are received in a storage container.

Abstract: A shaped article composed of an aromatic polyimide has a hollow, essentially spherical structure and a particle size of about 100 to about 1500 .mu.m, a density of about 1 to about 6 pounds/ft.sup.3 and a volume change of 1 to about 20% by a pressure treatment of 30 psi for 10 minutes at room temperature. A syntactic foam, made of a multiplicity of the shaped articles which are bounded together by a matrix resin to form an integral composite structure, has a density of about 3 to about 30 pounds/ft.sup.3 and a compression strength of about 100 to about 1400 pounds/in.sup.2.

Abstract: An improved process for manufacture of expandable polymer particles is provided. The continuous process disclosed produces expandable polymer pellets in a single step while eliminating many of the dangers inherent in processes of prior art employed for the same. The polymers produced herein are of uniform size, and may be molded into various articles of manufacture using existing equipment and techniques known to those skilled in the art.

Abstract: Expanded polyolefin particles are produced by impregnation of polyolefin granules with a volatile blowing agent in suspension under pressure and subsequent decompression. The blowing agent used is ammonia.

Abstract: Impurities dissolved in a solid polymer and/or trapped in the spacial volume of the polymer can be removed quickly and efficiently in one or more relatively short pressurization/depressurization cycles, using a penetrant fluid (e.g. carbon dioxide) having at least some solubility in the polymer. Polymers with inherently slow or delayed elastic recovery at the temperature or temperatures at which the cycle is carried out (e.g. within the range of 20 to 200.degree. C.) or polymers with a high T.sub.g are the ones most efficiently treated. The penetrant is used to expand the polymer matrix, increasing its spacial volume. The pressure is then decreased rapidly, so that the impurities will migrate out of the polymer matrix before the matrix has a chance to relax or return to substantially its original volume. Each complete cycle should last seconds or minutes rather than hours.

Abstract: In a process for producing expandable styrene polymers containing graphite particles by polymerization of styrene in aqueous suspension in the presence of two peroxides which decompose at different temperatures, the peroxide which decomposes at lower temperature is multifunctional and on decomposition forms two or more linked polymer chains.

Abstract: A continuous process for preparing bead-form expandable styrene polymers in which the styrene is prepolymerized in bulk to a conversion of 10 to 80%, the prepolymer is dispersed in liquid form in an aqueous phase in the presence of suspension stabilizers, and the polymerization of the prepolymer is completed in an aqueous suspension to a residual styrene content of less than 2000 ppm.

Abstract: A method of producing open porous spherical particles by polymerizing monovinyl monomers and divinyl monomers and/or polyvinyl monomers (cross-linkers) in an emulsion with the aid of an initiator. The method is characterized by the steps of (i) preparing a w/o/w emulsion which comprises an aqueous phase having emulsified therein droplets which contain a water-in-oil emulsion, wherein the oil phase in the droplets includes vinyl monomers and an emulsifier which provides an inverse emulsion and the droplets have a diameter smaller than 2,000 .mu.m, and wherein the total amount of water is between 75-99% (w/w); and (ii) thereafter initiating polymerization and isolating the particles, optionally after sieving, from the reaction mixture after the polymerization process. A population of open spherical porous polymer particles which have a diameter within the range of 50 .mu.m-2,000 .mu.

Abstract: The present invention aims to improve soundproof and heat insulating properties of a foamed plastic by reducing internal cells pressure inside foamed resins. A base polymer such as a polyester-based polyol and a volatile foaming agent having an conjugate unsaturated group (i.e., conjugate double carbon bonds and/or triple carbon bonds) such as chloroprene (bp. 51.degree. C.) and calcium stearate were blended and then mixed with a hardening agent such as hexamethylene diisocyanate. The volatile foaming agent existing in open cells of the foamed plastic sealed in the Al laminated film and between the film and the foamed plastic, i.e., gap, possesses an unsaturated group, such as isoprene. Thus polymerization may occur by irradiating with electron rays, and the inside of the foams and the gap region may be reduced in pressure while the bag of the laminated film retains its shape.

Abstract: A process for preparing polyolefin resin pre-expanded particles comprising imparting expandability to polyolefin resin expanded particles having a crystal structure which shows two melting points in a DSC curve and heat expanding expanded particles having expandability, in which the relation between heat expansion temperature and the amount of a fusion preventing agent being attached to the surface of the polyolefin resin expanded particles is represented by the inequality: t-T.sub.V .ltoreq.49.1C-27.0 (t is heat expansion temperature, C is the amount of the fusion preventing agent being attached to the surface of the polyolefin resin expanded particles and T.sub.V is saddle temperature between two peaks showing two respective melting points in the DSC curve), and t is within the temperature range represented by the inequality: T.sub.L -30.ltoreq.t.ltoreq.T.sub.V (T.sub.V is the same as defined above and T.sub.L is lower melting point of the two melting points).

Abstract: The present invention aims to improve soundproof and heat insulating properties of a foamed plastic by reducing internal cells pressure inside foamed resins. A base polymer such as a polyester-based polyol and a volatile foaming agent having an conjugate unsaturated group (i. e., conjugate double carbon bonds and/or triple carbon bonds) such as chloroprene (bp. 51.degree. C.) and calcium stearate were blended and then mixed with a hardening agent such as hexamethylene diisocyanate. The volatile foaming agent existing in open cells of the foamed plastic sealed in the Al laminated film and between the film and the foamed plastic, i.e., gap, possesses an unsaturated group, such as isoprene. Thus polymerization may occur by irradiating with electron rays, and the inside of the foams and the gap region may be reduced in pressure while the bag of the laminated film retains its shape.

Abstract: The object of the present invention is to provide a thermoexpandable microcapsule which can be expanded at a lower temperature without decrease of various properties such as chemical resistance and heat resistance; said thermoexpandable microcapsule contains at least two kinds of volatile expanding agents having different boiling points lower than softening temperature of a polymeric material forming a shell, production thereof; and a method of expanding the microcapsule in which it is subjected to first heating below the starting temperature of expanding and then to the second heating.

Abstract: The invention provides a process for the preparation of polyurethane microspheres, which comprises of preparing a solution of diol or polyol having a molecular weight in the range of 200-2000, crosslinker and a catalyst selected from amino or organometallic compounds, dispersing, this solution in dilute solution of stabilizer which consists of a block copolymer having the general formula ?A!.sub.n -?B!.sub.m where A and B are chemically and compositionally dissimilar segments and n and m segments are in between 30-115 and 10-60 units respectively, such that the sum of n and m does not exceed 175 units, in an aliphatic hydrocarbon, adding an isocyanate dropwise to this dispersion agitating the mixture at high speed of 100-1200 revolutions per minute, a temperature between 30.degree. to 55.degree. C. to permit the formation of polyurethane microspheres, separating these microspheres by filtration, washing with lower aliphatic hydrocarbon and drying the microspheres under vacuun.

Abstract: Foam materials based on copolymers of styrene with from 2 to 50 mol % of 1,1-diphenylethene have a high heat distortion resistance.

Abstract: Microspheres are described which have a shell of thermally expandable polymer and a hollow interior that contains a fluorinated hydrocarbon that boils at a temperature below the melting point of the polymer, and contains an organic ester or ether or ketone. The ester or ether or ketone improves the quality of microsphere product. The expandable particles are useful in insulation, packaging, for expanding other polymer such as polytetrafluoroethylene, and the like.

Abstract: Partially expanded polyolefin granules are post-expanded by a process comprising charging a vessel containing foamed polyolefin beads having a bulk density of from 20-450 g/l with an inert gas under a pressure of from 2-25 bar and at a temperature of from T.sub.m -150.degree. C. to T.sub.m -40.degree. C. over a period of from 1-48 h, and then continuously or discontinuously transferring the pressurized foam beads into an apparatus in which a fluidized bed is created, where the beads expand further at a temperature of from T.sub.m -75.degree. C. to T.sub.m +20.degree. C.The resultant foamed beads are suitable for producing foamed moldings.

Abstract: The invention provides a process for the preparation of polyurethane microspheres, which comprises of preparing a solution of diol or polyol having a molecular weight in the range of 200-2000, crosslinker and a catalyst selected from amino or organometallic compounds, dispersing this solution in dilute solution of stabilizer which consists of a block copolymer having the general formula ?A!.sub.n-- ?B!.sub.m where A and B are chemically and compositionally dissimilar segments and n and m segments are in between 30-115 and 10-60 units respectively, such that the sum of n and m does not exceed 175 units, in an aliphatic hydrocarbon, adding an isocyanate dropwise to this dispersion, agitating the mixture at high speed of 100-1200 revolutions per minute, a temperature between 30.degree. to 55.degree. C. to permit the formation of polyurethane microspheres, separating these microspheres by filtration, washing with lower aliphatic hydrocarbon and drying the microspheres under vacuum.

Abstract: Expandable styrene bead polymers having improved expandability contain from 1 to 20% by weight of a liquid oligomeric aliphatic olefin having 2 to 20 carbon atoms and a degree of polymerization of from 2 to 200.

Abstract: A continuous process for making moldable foam beads comprising a non-crosslinked or crosslinked thermoplastic polymer foam are produced by mixing a composition comprising a non-crosslinkable or crosslinkable thermoplastic polymer or a thermoplastic polymer with a crosslinking agent, additives to achieve specific properties, a blowing agent, extruding the admixture under pressure, crosslinking, when applicable, the admixture under pressure, modulating the admixtures temperature to achieve the desired foaming properties, and then expanding the admixture in a zone of lower pressure to form a foam bead that can be molded.

Abstract: A large-sized in-mold expansion-molded article of an olefin synthetic resin having 150 mm or more in thickness, 50% or more in fusion ratio and 10% or less in density distribution is disclosed. The expansion-molded article is obtainable by adoption of a process in which pre-expanded beads are charged into a mold, preheated and steamed before molding. Large-sized expansion-molded article of an olefin synthetic resin 500 mm or even more in thickness is obtainable by the present invention.

Abstract: A process for producing non-scattering hollow plastic balloons which comprises: (a) heating a mixture (A) of non-foamed plastic balloons and a first wetting agent, which is a plasticizer, to a temperature from 40.degree. C. to a temperature which is 40.degree. C. below an exit temperature of a heat exchanger, (b) contacting the mixture (A) with a second wetting agent being heated to a temperature equal to or above the foaming starting temperature of the non-foamed plastic balloons, wherein a ratio of the mixture (A) to the second wetting agent (B) is 1:0.5 to 1:1.5, the contacting being within 1 minute after heating the mixture (A) by the heat exchanger to a temperature ranging from 20.degree. to 50.degree. C. below the foaming starting temperature of the non-foamed plastic balloons, (c) foaming the non-foamed plastic balloons, and (d) cooling the resultant mixture from step (c) containing the foamed plastic balloons. Non-scattering foamed plastic balloons can thus be obtained simultaneously with the foaming.

Abstract: The subject invention pertains to a continuous process for expanding thermoplastic minipellets, particularly polypropylene. The minipellets are continuously expanded by continuously charging and mixing water and minipellets in a slurry tank to form a slurry which is subsequently pressurized. A blowing agent such as butane is entrained into the pressurized slurry flow, which said slurry is then heated by a heating means, such as a shell and tube heat exchanger, to the softening point of the minipellets. The heated minipellets are given the time necessary for impregnation by permitting them to flow through one or more impregnation vessels. The impregnated minipellets are released through an orifice into an expansion vessel where the blowing agent flashes off, thereby expanding the minipellets.

Abstract: The molded articles of foamed particles, which are produced by using foamed particles composed of a polypropylene-based polymer, have had excellent cushioning characteristics and impact resilience, but have been not always satisfactory in stiffness such as compressive strength.The invention is directed to foamed particles comprising a polypropylene homopolymer as a base resin and having a tensile modulus of 15,000-25,000 kg/cm.sup.2 and a crystal structure that an inherent peak and a high-temperature peak appear as endothermic peaks on a DSC curve obtained by differential scanning calorimetry of the foamed particles. A quantity of heat at the high-temperature peak is 30-60 J/g.A molded article of foamed particles according to the invention is obtained by using the foamed particles as described above and molding them, and has a density of 0.01-0.3 g/cm.sup.3 and a tensile modulus of 15,000-25,000 kg/cm.sup.2.

Abstract: Prefoamed polyolefin beads, produced by extrusion followed by granulation, have a crystal structure with a double peak.

Abstract: An expanded, memory molded, increased density, highly impact-resistant polystyrene construct, and method of making the construct. The construct is formed by molding pre-expanded non-equilibrated polystyrene beads to a first volume, cooling rapidly, and then compression molding to a final, smaller volume. The resultant constructs have increased density, and high impact strength without increase in embrittlement. Also, the construct has "memory" in the sense that it returns substantially to its original shape after impact.

Abstract: A coating powder consisting essentially of generally spherical particles ranging in size from less than 2 to about 40 microns, 75% of whose volume consists of particles of from about 2 to about 20 microns in size, is provided by dissolving the components of the coating powder in a supercritical fluid without the aid of a surfactant and spraying the solution into a zone whose pressure is less than that of the fluid. A very smooth continuous film of a cured thermosettable coating powder is achieved even when the film thickness is less than 1 mil, e.g., from about 0.2 and greater. The advantages of powder coatings may now be realized fully in the automobile and can industries.

Abstract: The present invention relates to expandable styrene polymers containing recycled polystyrene, having a recycled material content of from 10 to 50% by weight, based on the total weight of the polystyrene, to which alkyldi(2-hydroxyethyl)amines have been added during the polymerization.

Abstract: Stable and water-resistant aqueous foam composition containing (1) a long chain cationic organic compound and (2) a long-chain anionic organic compound in a weight ratio of from 0.05:1 to 15:1. The stable foam composition of the invention may be mixed with various water-soluble or water-dispersible organic, polymeric, or inorganic substances and used in applications where lightweight, heat, sound or other insulative, barrier properties or homogeneous material distribution are needed. Such applications include cementitious or gypsum containing substances, adhesives, binders, paper treating materials, coatings, ceramics, landfills, geofills, and firefighting and fireproofing materials.

Abstract: An expandable styrene resin bead containing voids therein, wherein the number of the voids present in the area from the surface of the bead to a depth of 0.1 mm along the radial direction is not more than 100 per mm.sup.2 as counted on a cross section passing through approximately the center of the bead. A process for producing expandable styrene resin beads by suspension polymerization is also disclosed in which a styrene monomer is suspended in an aqueous medium in the presence of an initiator and a suspending agent, and a blowing agent is incorporated into polymer beads produced, wherein an alkali metal salt or ammonium salt of persulfuric acid is added to the reaction system in an amount of 0.5 to 30 ppm based on the aqueous medium while the degree of conversion of said monomer is in the range of from 0 to 30%, and an electrolyte is added to the reaction system in a concentration of 0.02 to 5.0 mol/l based on the aqueous medium when the degree of conversion is 30% or higher.

Abstract: Polyurethane/urea elastomers having an isocyanate equivalent index below 100, preferably from about 15 to about 80; containing an effective amount of polyisocyanate component, and an effective amount of an isocyanate reactive component comprising at least one polyamine and at least one polyol, wherein said elastomer contains from about 1 to about 199 equivalent percent amine per isocyanate equivalent.

Abstract: The present invention relates to expandable beads based on a polymer of a vinylaromatic compound containing a blowing agent and, in an amount of 0.1 up to 2% wt, preferably 0.3 up to 1.5% wt calculated on the beads, of a plasticizer that is based on oligomers of styrene and/or alpha-methylstyrene having a number-average molecular weight (M.sub.n) in the range of 200 to 500, preferably of 260 to 460; and a process for preparing these expandable beads.

Abstract: A composite material is disclosed which comprises a shaped, expanded body having a closed cellular structure, and a layer of a thermosetting resin directly bonded to a surface of the shaped body, wherein the shaped body is formed of a mixed thermoplastic resin having a xylene-insoluble content of not greater than 1% by weight and containing at least 50% by weight of a polyolefin resin and at least 2% by weight of a polyene polymer having vinyl group-containing side chains.

Abstract: A substantially cylindrical bar of microporous PTFE is non-fibrillated and incorporates pores within any cylindrical surface within the bar centred about the central longitudinal axis of the bar that are of substantially uniform size and are substantially uniformly distributed within that surface. The process for producing such a bar includes the step of applying a substantially radial compressive force to pre-heated and cooled granules of PTFE and subsequently re-heating and cooling the compressed granules, while a film of non-fibrillated, microporous PTFE is formed from the cooled bar, the plane of the film being perpendicular to the direction of the radial compressive force whereby the pores within any plane substantially perpendicular to the thickness of the film are of substantially uniform size and are substantially uniformly distributed within that plane and all such parallel planes.

Abstract: The present invention relates to powdery, insoluble, water-swellable, cross-linked polymers absorbing water, aqueous or serous liquids, which are formed ofa) 55-99.9%-wt. polymerized unsaturated, polymerizable acid-groups--comprising monomers which are neutralized to the extent of at least 25 mol-%,b) 0-40%-wt. polymerized unsaturated monomers which are co-polymerizable with a),c) 0.1-5.0%-wt. of a cross-linking agent, andd) 0-30%-wt. of a water-soluble polymer,with the weight amounts of a) to d) being relative to anhydrous polymer, and the polymer powder is heated with an at least bifunctional compound reactive with acid groups to a temperature of 150.degree. C.-250.degree. C. under cross-linkage of the surface, and the polymer powder that is thus already surface-cross-linked is subjected to a repeated surface-cross-linking treatment using an at least bifunctional compound reactive with acid groups at a temperature of 150.degree. to 250.degree. C.

Abstract: In this invention a new form of polytetrafluoroethylene has been found to be compression moldable to provide exceptionally strong molded articles. It is also useful as an additive or strength binder. The new form is a compression molding powder comprised of comminuted, sheared particles of expanded porous polytetrafluoroethylene, said particles having a nudular-microfibrilar structure of irregular shape, and a mean particle size between 5 and 500 micrometers. By irregular shape is meant that the nodes and fibrils do not have an ordered arrangement. The bulk density is about 0.06 to 0.2 g/cc.

Abstract: A process for the preparation of bead-form expandable styrene polymers by polymerizing styrene, if desired in the presence of further comonomers, in aqueous suspension in the presence of organic molecular colloids as suspension stabilizers and conventional styrene-soluble polymerization catalysts and with addition of a blowing agent and, if desired, conventional additives in effective amounts, wherein the aqueous suspension contains at least one olefinically unsaturated carboxylic acid or a water-soluble salt thereof in an amount, based on the organic phase, of from 0.002 to 0.3% by weight of carboxylate anions.

Abstract: Expandable styrene resin beads are described, which, when expanded to a bulk density of 20 g/l, give pre-expanded beads in which the number of cells present along those surface parts of radii which range from the bead surface to a depth of 0.2 mm from the surface is from 3 to 20 per mm and the number of cells present along those inner parts of the radii which range from a depth of 1 mm from the bead surface to the bead center is 10 or larger per mm, the number of cells present along said surface parts being smaller than the number of cells present along said inner parts.

Abstract: A strippable pressure-sensitive adhesive and an adhesive material using the same are disclosed, adhesive comprising a highly elastic base polymer whose dynamic modulus of elasticity is in the range of from 250,000 to 10,000,000 dyne/cm.sup.2 at a temperature between ambient temperature and 150.degree. C. with a small rate of change with temperature, having incorporated therein a blowing agent, which adhesive reduces or loses its adhesiveness on expansion or blowing of blowing agent. The adhesive and adhesive material are easily re-applied, is capable of satisfactorily following the shape of an adherent during forming of the adherent, reduces its adhesiveness on heating, and is applicable to various adherents with excellent workability.