Abstract: Thermoplastic vulcanizate elastomer obtained by dynamic vulcanization of a heterophasic polyolefin composition in presence of at least (i) an alkenyl-substituted alkoxysilane grafting agent and (ii) water; wherein said heterophasic polyolefin composition has flexural modulus equal to or lower than 150 MPa, and comprises: (a) a crystalline propylene homopolymer or copolymer of propylene with up to 15% of ethylene or other alpha-olefin comonomer(s), or their combinations, and (b) a copolymer or a composition of copolymers of ethylene with other alpha-olefins, containing from 15% to 40% of ethylene, said thermoplastic vulcanizate elastomer having compression set values in the range from 45-65%, the ratio of elongation at break to compression set values over 10 and hardness shore A values below 90.

Abstract: A high solids, non-aqueous dispersion, clearcoat composition is disclosed, comprising a functional polymer selected from the group consisting of a) carbamate-functional polymers and b) hydroxyl-functional polymers; c) a curing agent selected from the group consisting of aminoplast resins and blocked polyisocyanates; and d) a weak non-polar solvent, wherein the coating is high solids, substantially clear and transparent, and further comprises a dispersed phase and a continuous phase.

Abstract: The adhesive composition of the invention comprises a thermoplastic resin, a radical polymerizing compound, a radical polymerization initiator and a radical polymerization regulator. According to the present invention it is possible to provide an adhesive composition, a circuit connecting material, a connection structure for a circuit member and a semiconductor device whereby curing treatment can be carried out with sufficient speed at low temperature, curing treatment can be carried out with a wide process margin, and adequately stable adhesive strength can be obtained.

Abstract: An object of the present invention is to provide a rubber composition which not only realizes sufficiently low heat generation properties but also exhibits more excellent crack growth resistance than the conventional rubber composition. The rubber composition contains in 100 mass % of rubber components thereof: 20-80 mass % of natural rubber in which the total nitrogen content in natural rubber latex is in the range of 0.1 mass % to 0.4 mass % (exclusive of 0.1 mass % and inclusive of 0.4 mass %); and butadiene-based polymer having cis content of 90% or higher.

Abstract: A cured adhesive composition comprising: (a) a copolymer comprising the reaction product of: 65 to 94.5 wt % of a C?8#191 acrylate ester, 0.5 to 5 wt % of a polar cross-linkable monomer, and 5-30 wt % of a non polar monomer, wherein the copolymer has a weight average molecular weight of 400,000 to 2,200,000 grains/mole; (b) 30 to 70 parts of a hydrogenated hydrocarbon tackifier per 100 parts of the copolymer; and (c) 0.01 to 3 parts (solid/solid) of a cross-linking agent per 100 parts of the copolymer wherein the cured adhesive has a peel value greater than 6 N/cm when tested according to FINAT test method No. 2 on a low density polyethylene; and further wherein the cured adhesive has a shear value greater than 2000 minutes when tested according to FINAT test method No. 8 on low density polyethylene. The cured adhesive of this disclosure is found to exhibit excellent adhesion to low surface energy substrates.

Abstract: A single-layered acrylic pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer formed of an acrylic pressure-sensitive composition. The acrylic pressure-sensitive adhesive composition contains an acrylic polymer (A) and a (meth)acrylic polymer (B) having glass transition temperature (Tg) such that Tg?45° C. and a mass average molecular weight (Mw) is such that 1500?Mw?4000.

Abstract: Processes for manufacturing a composition of a solvolysis product of an ethylene-vinyl ester copolymer, which comprises: conducting solvolysis of an ethylene-vinyl ester copolymer (A?) and a modified ethylene-vinyl ester copolymer (B?) comprising a unit derived from a compound represented by the general formula (2) in one system to manufacture the composition of a solvolysis product of an ethylene-vinyl ester copolymer comprising a solvolysis product (A) of the ethylene-vinyl ester copolymer and a solvolysis product (B) of the modified ethylene-vinyl ester copolymer comprising a unit represented by the general formula (1), wherein a ratio of an ethylene content (B?)/(A?) of copolymer (A?) and copolymer (B?) in conducting solvolysis is 1 or more, and a blending ratio (B?)/(A?) of the ethylene-vinyl ester copolymer (A?) and the modified ethylene-vinyl ester copolymer (B?) is from 50/50 to 1/99 by weight:

Abstract: This invention relates to a composition comprising a multiblock polyolefin represented by the formula: PO—C(R11)(R12)—C(R13)?C(R14)—C(R15)(R16)—PO*, or isomers thereof, wherein R11, R12, R13, R14, R15, and R16, are each independently a substituted or unsubstituted C1 through C4 hydrocarbyl group or a hydrogen; PO and PO* are polyolefins; PO and PO* are each independently a substituted or unsubstituted hydrocarbyl group having 9 to 4000 carbon atoms, provided that at least one of PO and PO* are C20 or greater, said polyolefin having: 1) an internal unsaturation as shown by the 13C NMR peak at between about 128 and about 132 ppm; 2) an Mn ratio “Z”=0.1 to 10 where Z is the Mn (as determined by 13C NMR) divided by Mn (as determined according to Gel Permeation Chromotography using polystyrene standards); and 3) optionally, from 0.3(J) and 0.

Abstract: Golf balls containing a core having at least one layer and cover having at least one layer are provided. A thermoplastic ionomeric composition is used to form at least one layer of the ball. The composition is prepared by providing a masterbatch comprising cycloalkene (polyalkenamer) rubber and neutralizing agent and mixing the masterbatch with ethylene acid copolymer. The acid groups are neutralized to 30 weight percent or greater, preferably 50% or greater, and more preferably 70% or greater. The resulting ball has high resiliency and rebounding properties along with a soft feel.

Abstract: Provided is a fiber-reinforced composite. The composite has a propylene polymer including 90 wt % or more of propylene monomeric units based on the weight of the propylene polymer; a plurality of fibers of a solid, flexible material grafted to the propylene polymer; and an elastomer. The fibers are present in the composite at 10 wt % to 80 wt % based on the total weight of the composite. The propylene polymer is present in the composite at from 30 wt % to 95 wt % based on the total weight of the composite. The elastomer is present in the composite at from 5 wt % to 50 wt % based on the total weight of the composite. Greater than 50 wt % of the fibers are dispersed within the propylene polymer based on the total weight of the fibers in the composite. There is also provided a process for making a fiber-reinforced composite.

Abstract: A material from which a cured film exhibiting high solvent resistance, liquid crystal-alignment performance, heat resistance and high transparency can be formed. A composition for forming a thermoset film having photo alignment properties, the composition comprising: a component (A) that is an acrylic copolymer having a photodimerizing moiety and a thermal cross-linking moiety; a component (B) that is an acrylic polymer having at least one of a C2-5 alkyl ester group and a C2-5 hydroxyalkyl ester group and at least one of a carboxy group and a phenolic hydroxy group; and a component (C) that is a cross-linking agent.

Abstract: A process for manufacturing a self-sealing elastomer composition, said process comprising the following steps: a masterbatch, comprising at least one diene elastomer and more than 30 phr of a hydrocarbon resin, is firstly manufactured by compounding these various components in a mixer at a temperature or up to a temperature called the “hot compounding” temperature which is above the softening point of the hydrocarbon resin; and then at least one crosslinking system is incorporated into the masterbatch thus prepared, by compounding everything in the same mixer or in a different mixer, at a temperature or up to a temperature which is kept below 100° C., in order to obtain said self-sealing composition.

Abstract: Blown films and processes of forming the same are described herein. The processes generally include providing a bimodal ethylene based polymer, blending the bimodal ethylene based polymer with at least about 30 ppm peroxide to form modified polyethylene and forming the modified polyethylene into a blown film.

Abstract: This invention relates to processes for the preparation of a dynamically vulcanized alloy comprising at least one isobutylene-containing elastomer and at least one thermoplastic resin. More specifically, the processes produce dynamically vulcanized alloys with unique morphological features which have good impermeability and low temperature flexibility.

Abstract: Dendritic macroinitiator compositions are provided comprising a compound of the general formula, Fx-[G-n]-I, where F is the chain end functional group of the dendrimer, x is the number of chain end functional groups, G is the dendrimer, n is the generation number of the dendrimer, and I is the initiating group. Hybrid dendritic-linear copolymers made from these macroinitators can act as highly efficient dispersing agents for a range of nanoparticles in matrix materials.

Abstract: This invention relates to a process to make a multimodal polyolefin composition comprising: (i) contacting at least one first olefin monomer with a mixed catalyst system, under polymerization conditions, to produce at least a first polyolefin component having a Mw of 5,000 g/mol to 600,000 g/mol, wherein the mixed catalyst system comprises: (a) at least one polymerization catalyst comprising a Group 4 or Group 5 transition metal; (b) at least one organochromium polymerization catalyst; (c) an activator; and (d) a support material; (ii) thereafter, contacting the first polyolefin component/mixed catalyst system combination with a molecular switch; (iii) contacting the first polyolefin component/mixed catalyst system combination with at least one second olefin monomer, which may be the same or different, under polymerization conditions; and (iv) obtaining a multimodal polyolefin composition.

Abstract: The invention relates to a polyethylene composition for the production of peroxide crosslinked polyethylene and a method for the production thereof. The invention further relates to the use of such a polymer composition and to a peroxide crosslinked polyethylene pipe made from the polyethylene composition.

Abstract: A method for producing an olefinic thermoplastic elastomer comprising the steps of kneading an olefin copolymer rubber (A) obtained by polymerizing ethylene, an ?-olefin having 3 to 20 carbon atoms and a non-conjugated polyene, a volatile organic solvent (B) and, an olefin resin (C) in an extruder, removing the volatile organic solvent (B) while kneading, then adding a crosslinking agent (E) and further removing the volatile organic solvent (B) while kneading in the extruder to obtain the olefinic thermoplastic elastomer.

Abstract: The adhesive composition of the invention comprises a thermoplastic resin, a radical polymerizing compound, a radical polymerization initiator and a radical polymerization regulator. According to the present invention it is possible to provide an adhesive composition, a circuit connecting material, a connection structure for a circuit member and a semiconductor device whereby curing treatment can be carried out with sufficient speed at low temperature, curing treatment can be carried out with a wide process margin, and adequately stable adhesive strength can be obtained.

Abstract: A dynamically vulcanized alloy contains at least one isobutylene-containing elastomer and at least one thermoplastic resin, wherein the elastomer is present as a dispersed phase of small particles in a continuous phase of the thermoplastic resin. The elastomer in the alloy is cured by means of a cure system comprising an increased amount of curative and preferably with no cure accelerators present in the cure system. The elastomer obtains at least seventy five percent cure in not more than 15 minutes at temperatures 220° C. or greater.

Abstract: A heterogeneous polymer blend comprises a dispersed phase comprising a thermoplastic first polymer having a crystallinity of at least 30% and a continuous phase comprising a second polymer different from the first polymer. The second polymer has a crystallinity of less than 20% and is at least partially cross-linked.

Abstract: The invention relates to processes for the production of microgel-containing rubber mixtures, to rubber mixtures obtainable by the processes, to processes for the production of vulcanizates, and also to vulcanizates after the vulcanization process, in particular in the form of tires, parts of tires, or industrial rubber items.

Abstract: The present invention relates to a partially-crystalline copolymer comprising tetrafluoroethylene, hexafluoropropylene in an amount corresponding to hexafluoropropylene index (HFPI) of from about 2.8 to 5.3, and preferably from about 0.2% to 3% by weight of perfluoro(alkyl vinyl ether), said copolymer having less than about 50 ppm alkali metal ion, having a melt flow rate of within the range of about 30±3 g/10 min, and having no more than about 50 unstable endgroups/106 carbon atoms and which can be extruded at high speed onto conductor over a broad polymer melt temperature range to give insulated wire of high quality.

Abstract: A method for producing an elastomeric sealing article including preparing a thermoplastic elastomeric resin composition having (a) 100 parts by weight of a hydrogenated block copolymer including at least two polymeric blocks (A) of styrene, and at least one polymeric block (B) of isoprene; (b) 70 to 130 parts by weight of an ethylene-octene copolymer including ethylene in an amount of more than 50% by weight; and (c) 30 to 60 parts by weight of polypropylene. The thermoplastic elastomeric resin composition does not contain a non-aromatic softening agent, and none of components (a), (b), and (c) is cross-linked. The method also includes molding the thermoplastic elastomeric resin composition into an elastomeric sealing article.

Abstract: A curable composition and an adhesive which exhibit a temporarily fixing effect very quickly and which are completely cured quickly at room temperature, and a bonding method using such a composition. The curable composition including a component (A)], which is a polymerizable acrylic liquid composition, a component (B), which is cumene hydroperoxide, a component (C), which is a reducing agent containing vanadium or copper, or a reducing agent comprising ethylene thiourea, and a component (D), which is a basic compound having a primary, secondary, or tertiary amine structure.

Abstract: Blends of syndiotactic 1,2-polybutadiene and rubbery elastomers are prepared by a process that comprises polymerizing 1,3-butadiene monomer into syndiotactic 1,2-polybutadiene within a rubber cement of an elastomeric terpolymer by using a chromium-based, molybdenum-based, or iron-based catalyst composition. Polymer composition comprising the blend with improved properties is also provided.

Abstract: Curable perfluoroelastomer compounds are prepared by mixing a composition comprising perfluoroelastomer, 1-20 phr fibrillating PTFE, and curative for a time ML (ASTM D5289), measured on sequential samples of compound taken at 5 minute intervals, differ by less than 5%. Articles are made therefrom by curing the compounds to form crosslinks.

Abstract: A cross-metathesized product mixture is prepared by contacting a metathesis catalyst under metathesis conditions with a composition comprising two or more chemically distinguishable ethylenically unsaturated polymers, at least one of said ethylenically unsaturated polymers (first polymer) having from 0.001 to 50 mole percent unsaturation and at least one other of said ethylenically unsaturated polymers (second polymer) being an amorphous polymer having a Tg less than 0° C. and having from 0.001 to 5 mole percent unsaturation.

Abstract: The present invention relates to a process for preparing a thermoplastic vulcanizate (TPV) comprising: contacting a thermoplastic polymer, a cross-linkable elastomer, at least one curative, and at least one cure activator in a solvent to form Composition A. The solvent is then removed, and thereafter the cross-linkable elastomer is at least partially cured. The average particle size of the cross-linkable elastomer is 10 microns or less after the solvent is removed.

Abstract: The invention provides polymer blends containing polyhydroxyamide and one or more flammable polymers. The polymer blends are flame retardant and have improved durability and heat stability compared to the flammable polymer portion of the blends. Articles containing the polymer blends are also provided.

Abstract: A method for preparing a thermoplastic vulcanizate, the method comprising dynamically vulcanizing a rubber within a blend that includes the rubber and a thermoplastic polymer, where said dynamically vulcanizing is effected with a cure system that includes a hydrosilating agent and a catalyst, where the hydrosilating agent includes a compound including at least 3 silicon hydride groups defined by the formula where each R is independently a monovalent organic group or hydrogen, and where the silicon atoms of the respective silicon hydride groups are spatially separated by at least 6 atoms.

Abstract: The invention provides a composition that contains at least one specific non-crosslinkable organic medium at least one microgel and at least one thickening agent, a process for the preparation thereof and uses of the compositions.

Abstract: Provided are a pressure sensitive adhesive composition for optical members and a pressure sensitive adhesive composition for optical members. The pressure sensitive adhesive composition for optical members according to the present invention comprises 100 parts by weight of an acrylic polymer (A) having a weight-average molecular weight of 500,000 or more, containing at least 50 wt % alkyl (meth)acrylate having an alkyl group with 5 or more carbon atoms and 0.2 to 2 wt % unsaturated carboxylic acid as the monomer unit, 0.1 to 4 parts by weight of an acrylic polymer (B) having a weight-average molecular weight of 2,000 to 50,000, containing at least 70 wt % alkyl (meth)acrylate and 1 to 7 wt % unsaturated carboxylic acid as the monomer unit and having a higher carboxylic acid equivalent than that of the acrylic polymer (A), 0.01 to 1 part by weight of a silane coupling agent, and a crosslinking agent.

Abstract: A hyperbranched polymer synthesizing method employs living radical polymerization of a monomer in the presence of a metal catalyst.

Abstract: In one embodiment is a thermoplastic vulcanizates having improved extrusion properties formed from a composition that includes from 20% to about 80% by weight of an elastomer, from about 80% to about 20% by weight of a thermoplastic, from about 0.05 to about 12 phr of a multifunctional methacrylate monomer peroxide curing coagent; and from about 0.02 to about 6 phr of a phosphorous containing stabilizer. The resultant thermoplastic vulcanizate may be cured with a peroxide curing agent and shows improved die lip build up compared to conventionally prepared thermoplastic vulcanizates. Methods of forming thermoplastic vulcanizates having improved die lip build up are also taught.

Abstract: The present invention relates to a process for preparing a thermoplastic vulcanizate (TPV) comprising: contacting a thermoplastic polymer, a cross-linkable elastomer, at least one curative, and at least one cure activator in a solvent to form Composition A. The solvent is then removed, and thereafter the cross-linkable elastomer is at least partially cured. The average particle size of the cross-linkable elastomer is 10 microns or less after the solvent is removed.

Abstract: A composition that includes functionalized polymers and one or more types of particulate filler exhibits both an increased gum Mooney viscosity and a decreased compound Mooney viscosity relative to a comparable composition that includes only one such functionalized polymer. The functionalized polymers include first and second types of functionalities which exhibit a non-covalent interaction that has a bond energy of from about 0.1 to about 20 kJ/mol.

Abstract: The present invention provides a crosslinked propylene-based elastomer having an isotactic propylene triad tacticity of from 65 to 95%, a melting point by DSC equal to or less than 110° C., a heat of fusion of from 5 J/g to 50 J/g, and a haze % per 100 mil thickness of 95 or less, and comprising at least 75 wt % propylene-derived units, at least 5 wt % ethylene-derived units, and optionally 10 wt % or less of diene-derived units. In an embodiment, the present invention is a blend of a continuous phase of the crosslinked propylene-based elastomer and a dispersed phase of a crystalline polymeric compound. The present invention also provides elastomeric compositions comprising a crosslinked propylene-based elastomer as described herein and 100 parts by weight or less of a pigment per 100 parts of polymer. The present invention also provides films, fibers, nonwovens, molded objects, and extruded forms which include any of the inventive compositions described herein.

Abstract: This invention relates to the preparation of thermoplastic vulcanizates (TPVs) with unique morphological features, more specifically, this invention relates to a method for preparing TPV compositions wherein the mixing of plastomers and elastomers are carried out in solvent with curatives to induce cross-linking.

Abstract: Interpolymer resin particles comprised of 20% to 60% by weight of uncross-linked polyolefin e.g. polyethylene, polypropylene, and from 40% to 80% by weight based on the weight of the particles of a vinyl aromatic monomer, e.g. styrene, that is polymerized in a suspension process to form an interpenetrating network of polyolefin with polymerized vinyl aromatic monomer particles and having a gel content of 0 to 1.5% by weight based on the weight of the particles for improved processability in end-use applications and improved ESCR properties. The interpolymer resin particles have a VICAT softening temperature from about 90° C. to about 115° C., and a melt index from 0.2 to 35.0 g/10 minutes (Condition G). The particles can be mixed with a blowing agent to form extruded foam articles, such as foam board, and can be used in extrusion, injection molding, rotomolding, and thermoforming processes to form a layer, e.g.

Abstract: The present invention provides an organopolysilmethylene represented by the following general formula (1): wherein R1 is, independently of each other, a group selected from the group consisting of an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group, a hydroxy group, R3SiCH2— and R3SiO—, wherein R is, independently of each other, a group selected from the group consisting of an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group, and a hydroxy group, m is an integer of 1 to 100, and n is an integer of 1 to 100, and wherein at least two out of R1's and R's are an alkenyl group.

Abstract: A tire prepared by using a rubber composition compounded with a modified conjugated diene base polymer obtained by reacting an active site of a conjugated diene base polymer with a hydrocarbyloxysilane compound which may have a functional group to introduce a functional group having high affinity with precipitated silica and precipitated silica in which a cetyltrimethylammonium bromide-adsorbing specific surface area (CTAB) (m2/g) and the mode Aac in diameters (nm) of primary aggregates determined by acoustic measurement of particle size distribution satisfy equation (A) shown below: Aac??0.

Abstract: A method of preparing a thermoplastic vulcanizate, the method comprising continuously dynamically vulcanizing a rubber within a blend with a thermoplastic resin, where the dynamic vulcanization is effected with a cure system that includes a free-radical cure agent, and a coagent-wetted carrier where the coagent-wetted carrier includes a multi-functional acrylate coagent, a multi-functional methacrylate coagent, or both a multi-functional acrylate and multi-functional methacrylate coagent.

Abstract: Compositions comprising a plurality of carbon nanotubes, a host polymer, and A block copolymer comprising a first block and a second block, wherein no block is compatible with the host polymer. In one aspect, the block copolymer is amphiphilic. In another aspect, the block copolymer may comprise a first block and a second block, wherein at least one of the first and second blocks comprises repeating units derived from a monomer having the general formula: (R)2C?C(R)(Rf) wherein Rf is selected from fluorine, a C1 to C10 fluorinated or perfluorinated alkyl group, and a C1 to C10 fluorinated or perfluorinated alkoxy group; each R is independently selected from F, H, Cl, Rf, a C1 to C10 alkyl group, and R2A, wherein R2 is a C1 to C10 alkylene group and A is selected from CO2M and SO3M, wherein M is selected from H, an ammonium and organo onium group.

Abstract: A thermoplastic vulcanizate comprising a dynamically-cured rubber, where the rubber is selected from the group consisting of ethylene-propylene-non-conjugated diene rubber, propylene-based rubbery copolymers with units derived from non-conjugated diene monomers, and butyl rubber, where dynamic vulcanization is effected with a phenolic resin or a silicon-containing curative, and where the rubber is dynamically cured to an extent where greater than 94% by weight of the rubber is insoluble in cyclohexane at 23° C., and from about 25 to about 250 parts by weight of a thermoplastic polymer phase per 100 parts by weight rubber, where from about 75% to about 100% by weight of said thermoplastic polymer phase includes a butene-1-based polymer.

Abstract: A method for compounding a plastic material is provided, wherein the following steps are carried out: a) providing at least one ethylenic polymer; b) addition of at least one cross-linking agent to the ethylenic polymer; c) at least partial cross-linking of the ethylenic polymer by the cross-linking agent; d) addition of at least one propylenic polymer to the product obtained in step c); and e) at least partial cross-linking of the propylenic polymer with the product obtained in step c). Further, a plastic material producible by this method, and a plastic product made out of it are provided.

Abstract: A highly active and environment-friendly catalyst for use in a living radical polymerization is provided. A catalyst for use in a living radical polymerization method is provided. The catalyst comprises a central element, which is selected from nitrogen and phosphorus, and at least one halogen atom, which is bound to the central element. A monomer having a radical reactive unsaturated bond is subjected to a radical polymerization reaction in the presence of the catalyst, thereby it is possible to obtain a polymer having narrow molecular weight distribution. The present invention has the merits such as low toxicity of the catalyst, a small amount of the catalyst being required, high solubility of the catalyst in the polymerization media, mild reaction conditions, no coloration, no odor (unnecessary post-treatment of molded products). The method of the present invention is more environment-friendly and economical than other living radical polymerization methods.

Abstract: At least partially hydrolyzed chlorosulfonated polyolefin elastomers containing 0.5-10 weight percent chlorine and 0.25 to 5 weight percent sulfur are prepared from low density polyethylene or from linear ethylene/alpha-olefin copolymer base resins having a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) less than 3.5.

Abstract: The present invention relates to a polymer electrolyte membrane for a fuel cell, a method for manufacturing the polymer electrolyte membrane, a membrane-electrode assembly for a fuel cell including the polymer electrolyte membrane, and a fuel cell system including the membrane-electrode assembly. The polymer electrolyte membrane includes a proton-conductive polymer membrane including a polymer micelle inside a hydrophilic channel. Herein, the micelle includes a vinyl-based polymer obtained from polymerization of a vinyl-based monomer and an anionic surfactant surrounding the vinyl-based polymer.

Abstract: A polyol-crosslinkable fluororubber composition comprises 100 parts by weight of polyol-crosslinkable fluororubber; 0.5 to 10 parts by weight of a perfluoroalkane represented by the general formula F(CF2)2nF (n: 5˜30), a 1H-perfluoroalkane represented by the general formula F(CF2)mH (m: 10˜30), or a mixture thereof; 0.5 to 2 parts by weight of basic magnesium aluminum hydroxycarbonate hydrate; and 1 to 5 parts by weight of an acid acceptor compound excluding Ca compounds.