Resin composition for cap stock

Abstract

The present invention provides a resin composition for cap stock containing a vinyl chloride resin, which has high impact strength and elastic modulus, as well as excellent color development, resistance to hot water whitening, and processability. [Solution] The present invention provides a resin composition for cap stock containing a vinyl chloride resin (A), a block copolymer (B) comprising a polymer block (B1) containing acrylic acid ester units and a polymer block (B2) containing methacrylic acid ester units, a graft copolymer (C) obtained by polymerizing a monomer component containing one or more monomers selected from the group consisting of vinyl cyanide compounds, aromatic vinyl compounds, and alkyl (meth)acrylate esters to a rubbery polymer, and a copolymer (D) containing aromatic vinyl compound units and vinyl cyanide compound units.

Description

Technical Field

[0001] The present invention relates to a resin composition for capstock.

Background Art

[0002] Capstock is used to enhance weather resistance, design properties, etc. by covering the surface of materials such as polyvinyl chloride (PVC), and is also referred to as a decorative film or a decorative film. Capstock can be formed as an epidermis on the surface of a foam by co-extruding a resin composition for capstock and a foamed polyvinyl chloride composition. Such a foam with capstock is used for household decks and the like.

[0003] Examples of the resin composition for capstock include a thermoplastic composition containing a halogen-containing polymer, a thermoplastic polyurethane, and at least one acrylic polymer (for example, Patent Document 1), and a resin composition for capstock containing a block copolymer composed of 5 to 95% by weight of a methacrylic polymer block and 95 to 5% by weight of an acrylic polymer block (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, since cap stock can turn white after getting wet from rain or other sources and then being exposed to sunlight, excellent resistance to hot water whitening is also required. However, the cap stock described in Patent Document 1, which includes thermoplastic polyurethane, does not have a sufficient balance between resistance to hot water whitening and impact strength, and improvements were needed. Furthermore, when cap stock is used as a building material, it is important that it has excellent flame retardancy in order to delay the spread of fire. However, the cap stock described in Patent Document 2 does not have a sufficient balance between impact strength and flame retardancy, and improvements were needed. In addition, it is desirable that the cap stock contains a polyvinyl chloride resin in order to enhance its flame retardancy. Furthermore, when the cap stock is colored with pigments (such as carbon black), it may be required that the color appears beautifully (excellent color development). Furthermore, the cap stock may also be required to have a high modulus of elasticity from the standpoint of wear resistance and heat resistance. Furthermore, when producing cap stock from a cap stock resin composition, the cap stock resin composition may also be required to have excellent processability.

[0006] However, resin compositions for cap stocks containing vinyl chloride resins that exhibit high impact strength and elastic modulus, as well as excellent color development, resistance to hot water whitening, and processability, have not been sufficiently investigated to date.

[0007] Therefore, the object of the present invention is to provide a resin composition for cap stock containing a vinyl chloride resin that has high impact strength and elastic modulus, as well as excellent color development, resistance to whitening in hot water, and processability. [Means for solving the problem]

[0008] The present invention relates to a vinyl chloride resin (A), A block copolymer (B) comprising a polymer block (B1) containing acrylic acid ester units and a polymer block (B2) containing methacrylic acid ester units, A graft copolymer (C) obtained by polymerizing a rubbery polymer with a monomer component containing one or more monomers selected from the group consisting of vinyl cyanide compounds, aromatic vinyl compounds, and alkyl (meth)acrylate esters, Copolymer (D) containing aromatic vinyl compound units and vinyl cyanide compound units This relates to a resin composition for cap stock containing [a specific compound / component]. [Effects of the Invention]

[0009] According to the present invention, a resin composition for cap stock containing a vinyl chloride resin can be provided that has high impact strength and elastic modulus, as well as excellent color development, resistance to whitening in hot water, and processability. [Modes for carrying out the invention]

[0010] The following describes one embodiment of the present invention.

[0011] The resin composition for cap stock according to this embodiment (also referred to as the "resin composition") contains a vinyl chloride resin (A) (also referred to as "component (A)"), a block copolymer (B) (also referred to as "component (B)") comprising a polymer block (B1) containing acrylic acid ester units and a polymer block (B2) containing methacrylic acid ester units, a graft copolymer (C) (also referred to as "component (C)") obtained by polymerizing a monomer component containing one or more monomers selected from the group consisting of vinyl cyanide compounds, aromatic vinyl compounds, and alkyl (meth)acrylate esters to a rubbery polymer, and a copolymer (D) (also referred to as "component (D)") comprising aromatic vinyl compound units and vinyl cyanide compound units.

[0012] <<Vinyl chloride resin (A)>> The resin composition according to this embodiment contains a vinyl chloride resin (A). As a result, the resin composition according to this embodiment has high impact strength, flame retardancy, color development, resistance to whitening in hot water, and excellent processability. Furthermore, when the substrate to which the cap stock is attached is formed of a vinyl chloride resin, the adhesion between the cap stock and the substrate is improved.

[0013] Examples of vinyl chloride resins (A) include resins having a structure in which one or more hydrogen atoms in the monomer units of polyolefin or polydiene are replaced with chlorine. Examples of vinyl chloride resins (A) include polyvinyl chloride, polychlorinated vinyl chloride, polyvinylidene chloride, chlorinated polyethylene, vinyl chloride vinyl acetate copolymer, vinyl chloride ethylene copolymer, and chloroprene rubber. These may be used individually or in combination of two or more. The vinyl chloride resin (A) is preferably polyvinyl chloride.

[0014] The average degree of polymerization of the vinyl chloride resin (A) is preferably 300 to 7000, and more preferably 400 to 3000.

[0015] The resin composition according to this embodiment may further contain additives in addition to components (A), (B), (C), and (D).

[0016] The resin composition according to this embodiment may further contain a processing aid as an additive. By adding a processing aid, the processability of the resin composition can be further improved while simultaneously reducing melt viscosity and maintaining mechanical strength. The amount of processing aid is preferably 0.2 to 10 parts by weight, more preferably 0.5 to 7 parts by weight, and even more preferably 1 to 5 parts by weight, per 100 parts by weight of the vinyl chloride resin. Note that if the amount of processing aid is too large, there is a risk that the dispersibility of the processing aid in the vinyl chloride resin will decrease and the melt viscosity will increase. Examples of processing aids include Kane Ace (registered trademark) PA-20 (manufactured by Kaneka Corporation), Kane Ace (registered trademark) PA-40 (manufactured by Kaneka Corporation), etc. For example, the processing aid may be a polymer. Examples of monomers constituting the processing aid polymer include vinyl cyanide compounds, aromatic vinyl compounds, alkyl methacrylates, and other vinyl compounds copolymerizable with these. These may be used alone or in combination of two or more. The weight average molecular weight of the processing aid may be 100,000 or more, or may be 100,000 or more and 8,000,000 or less.

[0017] Examples of the additives include impact modifiers, stabilizers (e.g., Sn stabilizers, etc.), lubricants, plasticizers, colorants (e.g., pigments, etc.), fillers, foaming agents, etc., in addition to the processing aids. These may be used alone or in combination of two or more.

[0018] The vinyl chloride resin composition containing the additive and component (A) may be mixed with component (B), component (C), and component (D) to incorporate the additive into the resin composition according to this embodiment.

[0019] The vinyl chloride resin composition can be obtained by mixing various components and kneading at, for example, 100 to 200°C using a kneader such as a Banbury mixer, a kneader, a roll, a ribbon blender, a Henschel mixer, etc.

[0020] For the resin composition according to this embodiment, based on a total of 100% by weight of component (A), component (B), component (C), and component (D), the proportion of component (A) is preferably 20 to 60% by weight, more preferably 25 to 55% by weight, and still more preferably 30 to 50% by weight. Thereby, the resin composition according to this embodiment has even higher impact strength and is even more excellent in flame retardancy, color development, resistance to heat water whitening, and processability.

[0021] <<Block copolymer (B)>> The resin composition according to this embodiment contains one or more polymer blocks (B1) containing acrylic acid ester units and a block copolymer (B) containing one or more polymer blocks (B2) containing methacrylic acid ester units. As a result, the resin composition according to this embodiment has high impact strength, excellent color development, resistance to whitening in hot water, and excellent processability.

[0022] <Polymer block (B1)> The block copolymer (B) comprises a polymer block (B1) containing acrylic acid ester units. Examples of acrylic acid esters include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, isobornyl acrylate, lauryl acrylate, and benzyl acrylate. Other examples include acrylic acid esters having functional groups such as phenoxyethyl acrylate. These may be used individually or in combination of two or more. Among these, acrylic acid esters without functional groups are preferred, and n-butyl acrylate is more preferred.

[0023] The content of acrylic acid ester units in the polymer block (B1) is preferably more than 50% by weight and 100% by weight or less, and may be 100% by weight. The lower limit of the content is preferably 60% by weight or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0024] The proportion of polymer blocks (B1) in the block copolymer (B) is preferably 40 to 90% by weight. As a result, the resin composition according to this embodiment has even higher impact strength and even better color development, resistance to whitening in hot water, and processability. This proportion is more preferably 45-85% by weight, and even more preferably 50-80% by weight. Furthermore, from the viewpoint of further increasing the modulus of elasticity, this ratio is more preferably 40% by weight or more and less than 80% by weight, even more preferably 45-75% by weight, and particularly preferably 50-70% by weight. This ratio can be measured by the method described in the examples below.

[0025] <Polymer Block (B2)> The polymer block (B2) includes a polymer block (B2) containing methacrylate units. Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, isobornyl methacrylate, phenyl methacrylate, and benzyl methacrylate, which do not have functional groups; and methacrylic acid esters having functional groups such as methoxyethyl methacrylate, ethoxyethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2-aminoethyl methacrylate, glycidyl methacrylate, and tetrahydrofurfuryl methacrylate. These may be used individually or in combination of two or more types. Among these, methyl methacrylate, ethyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, phenyl methacrylate, and benzyl methacrylate are preferred, with methyl methacrylate being more preferred because it results in clearer phase separation between polymer block (B1) and polymer block (B2), and thus improves the mechanical properties of the resin composition.

[0026] The content of methacrylate ester units in the polymer block (B2) is preferably more than 50% by weight and 100% by weight or less, and may be 100% by weight. The lower limit of the content is preferably 60% by weight or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0027] The proportion of polymer blocks (B2) in the block copolymer (B) is preferably 10 to 60% by weight. As a result, the resin composition according to this embodiment has even higher impact strength and even better color development, resistance to whitening in hot water, and processability. This proportion is more preferably 15-55% by weight, and even more preferably 20-50% by weight. This ratio can be measured by the method described in the examples below.

[0028] Polymer block (B1) may contain methacrylic acid ester units to the extent that it does not impair the effects of the present invention. Polymer block (B2) may also contain acrylic acid ester units to the extent that it does not impair the effects of the present invention. Polymer block (B1) and polymer block (B2) may each contain monomer units other than (meth)acrylic acid ester. Examples of such other monomers include vinyl monomers having carboxyl groups such as (meth)acrylic acid, crotonic acid, maleic acid, and fumaric acid; aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, and m-methylstyrene; conjugated diene monomers such as butadiene and isoprene; olefin monomers such as ethylene, propylene, isobutene, and octene; lactone monomers such as ε-caprolactone and valerolactone; and (meth)acrylamide, (meth)acrylonitrile, maleic anhydride, vinyl acetate, vinyl chloride, and vinylidene chloride.

[0029] <Other polymer blocks> The block copolymer (B) may have other polymer blocks in addition to the polymer block (B1) and the polymer block (B2), as needed. Other polymer blocks include, for example, polymer blocks containing structural units derived from monomers such as styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, acrylonitrile, methacrylonitrile, ethylene, propylene, isobutene, butadiene, isoprene, octene, vinyl acetate, maleic anhydride, vinyl chloride, and vinylidene chloride; and polymer blocks consisting of polyethylene terephthalate, polylactic acid, polyurethane, and polydimethylsiloxane. Furthermore, the concept of other polymer blocks also includes hydrogenated polymer blocks containing structural units derived from conjugated dienes such as butadiene and isoprene.

[0030] The block copolymer (B) preferably has two or more polymer blocks (B2). In this case, the polymer blocks (B2) may be the same or different. Furthermore, it is more preferable that the block copolymer (B) is a triblock copolymer composed of polymer block (B2)-polymer block (B1)-polymer block (B2). As a result, the resin composition according to this embodiment has even higher impact strength and even better color development, resistance to whitening in hot water, and processability.

[0031] The weight-average molecular weight of the block copolymer (B) is preferably 30,000 to 300,000. This results in the resin composition according to this embodiment having even higher impact strength, and even better color development, resistance to whitening in hot water, and processability. The weight-average molecular weight is more preferably 40,000 to 200,000, and even more preferably 50,000 to 150,000. The weight-average molecular weight can be measured by the method described in the examples below.

[0032] In the resin composition according to this embodiment, the proportion of component (B) is preferably 8 to 30% by weight, and more preferably 9 to 25% by weight, relative to 100% by weight of the total of components (A), (B), (C), and (D).

[0033] <Method for producing block copolymer (B)> The method for producing the block copolymer (B) can be a known method and is not particularly limited, but for example, living polymerization can be used. Examples of methods for producing block copolymers (B) by living polymerization include a method of living polymerization using an organo-rare-earth metal complex as a polymerization initiator (see Japanese Patent Publication No. 06-93060), a method of living anionic polymerization using an organo-alkali metal compound as a polymerization initiator in the presence of mineral salts such as alkali metals or alkaline earth metals (see Japanese Patent Publication No. 05-507737), a method of living anionic polymerization using an organo-alkali metal compound as a polymerization initiator in the presence of an organo-aluminum compound (see Japanese Patent Publication No. 11-335432), and atomic transfer radical polymerization (ATRP) (see Macromolecular Chemistry and Physics, 2000, Vol. 201, pp. 1108-1114). Of the above methods, the method of living anionic polymerization using an organoalkali metal compound as a polymerization initiator in the presence of an organoaluminum compound is preferred because it results in a highly transparent block copolymer, has fewer residual monomers and suppresses odor, and can suppress the generation of bubbles when preparing the resin composition. It is also preferred because the molecular structure of the polymer block (B2) containing methacrylate units becomes highly syndiotactic, which has the effect of improving the heat resistance of the resin composition.

[0034] <<Graft copolymer (C)>> The resin composition according to this embodiment contains a graft copolymer (C) obtained by polymerizing a rubbery polymer with a monomer component comprising one or more monomers selected from the group consisting of vinyl cyanide compounds, aromatic vinyl compounds, and alkyl (meth)acrylate esters. As a result, the resin composition according to this embodiment has even higher impact strength and even better color development. The graft copolymer (C) comprises a trunk portion that is a rubbery polymer and branch portions.

[0035] <Rubber-based polymer> Examples of the aforementioned rubbery mass include diene-based rubbery masses, acrylic-based rubbery masses, polyorganosiloxane-based rubbery masses, and natural rubbery masses. These may be used individually or in combination of two or more types.

[0036] (Diene-based rubbery mass) A diene-based rubbery mass is a rubbery mass that contains constituent units derived from diene monomers as its constituent units.

[0037] Examples of diene monomers include 1,3-butadiene, isoprene(2-methyl-1,3-butadiene), and 2-chloro-1,3-butadiene. These diene monomers may be used individually or in combination of two or more.

[0038] The diene-based rubbery mass may further contain, as constituent units, constituent units derived from vinyl monomers other than diene monomers that are copolymerizable with diene monomers.

[0039] Examples of vinyl monomers other than diene monomers that can copolymerize with diene monomers (hereinafter also referred to as vinyl monomer A) include: (a) aromatic vinyl monomers such as styrene, α-methylstyrene, monochlorostyrene, and dichlorostyrene; (b) vinyl carboxylic acids such as acrylic acid and methacrylic acid; (c) alkyl (meth)acrylates such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate; (d) methacrylate Examples include (a) hydroxyl group-containing vinyl monomers such as 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate; (b) glycidyl group-containing vinyl monomers such as glycidyl methacrylate and 4-hydroxybutyl acrylate glycidyl ether; (c) unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile; (d) vinyl halides such as vinyl chloride, vinyl bromide, and chloroprene; (e) vinyl acetate; and (i) alkenes such as ethylene, propylene, butylene, and isobutylene. The vinyl monomer A described above may be used alone or in combination of two or more types.

[0040] The content of constituent units derived from vinyl monomer A in the diene-based rubbery mass is not particularly limited. Preferably, the diene-based rubbery mass contains, out of 100% by weight of constituent units, more than 50% by weight and 100% by weight or less of constituent units derived from diene monomer, and 0% by weight or more and less than 50% by weight of constituent units derived from vinyl monomer A. The diene-based rubbery mass may further contain as constituent units units derived from polyfunctional monomers such as diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, divinylbenzene, allyl methacrylate, ethylene glycol dimethacrylate, and 1,3-butylenedimethacrylate. In other words, these polyfunctional monomers may be used in the polymerization of the diene-based rubbery mass. Suitable diene-based rubbery masses include butadiene rubber (polybutadiene rubber), styrene / butadiene copolymer rubber (poly(styrene / butadiene) rubber), poly(acrylonitrile / butadiene) rubber, and butadiene / acrylic acid ester copolymer. Butadiene rubber is a rubbery mass containing more than 50% by weight and up to 100% by weight of butadiene-derived constituent units out of 100% by weight of constituent units.

[0041] (Acrylic rubber-based heavy material) Acrylic rubbery masses are rubbery masses that contain constituent units derived from (meth)acrylate monomers as constituent units.

[0042] Examples of (meth)acrylate monomers include (a) alkyl (meth)acrylate esters having an alkyl group with 1 to 22 carbon atoms, such as (a)methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate; (b) aromatic ring-containing (meth)acrylate esters such as phenoxyethyl (meth)acrylate and benzyl (meth)acrylate; (c) hydroxyalkyl (meth)acrylate esters such as 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate; (d) glycidyl group-containing (meth)acrylate esters such as glycidyl (meth)acrylate and glycidyl alkyl (meth)acrylate; and (e) alkoxyalkyl (meth)acrylate esters. These (meth)acrylate monomers may be used individually or in combination of two or more.

[0043] The acrylic rubbery mass may further contain, as constituent units, constituent units derived from vinyl monomers other than (meth)acrylate monomers that are copolymerizable with (meth)acrylate monomers.

[0044] Examples of vinyl monomers other than (meth)acrylate monomers that can copolymerize with (meth)acrylate monomers include (a) the diene monomers mentioned above, and (b) monomers other than (meth)acrylate monomers among vinyl monomer A. The acrylic rubbery mass may have a crosslinked structure. To introduce a crosslinked structure, for example, a crosslinking agent and / or a graft crossing agent can be used when polymerizing monomer components to synthesize the acrylic rubbery mass. Examples of crosslinking agents and graft crossing agents include (a) allylalkyl(meth)acrylates such as allyl(meth)acrylate and allylalkyl(meth)acrylate; (b) polyfunctional (meth)acrylates such as monoethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate and tetraethylene glycol di(meth)acrylate; and (c) polyfunctional monomers such as diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and divinylbenzene. These crosslinking agents and graft crossing agents may be used individually or in combination of two or more. Suitable examples of acrylic rubbery masses include acrylate-based rubbers such as butyl polyacrylate rubber and butyl acrylate / 2-ethylhexyl acrylate copolymer rubber. Butyl polyacrylate rubber is a rubbery mass containing more than 50% by weight and up to 100% by weight of constituent units derived from butyl acrylate out of 100% by weight of constituent units.

[0045] (Polyorganosiloxane-based rubbery mass) Examples of polyorganosiloxane-based rubbery masses include silicone rubber and silicone / acrylate-based rubber. Examples of silicone rubbers include polymethyl silicone rubber and polymethylphenyl silicone rubber. Examples of silicone / acrylate-based rubbers include polyorganosiloxane / butyl acrylate copolymer.

[0046] The weight percentage of the rubbery polymer in the total graft copolymer (C) is preferably 45 to 85% by weight, more preferably 50 to 75% by weight, and even more preferably 55 to 70% by weight. As a result, the resin composition according to this embodiment has even higher impact strength and even better color development, resistance to whitening in hot water, and processability.

[0047] The graft copolymer (C) preferably includes a graft copolymer (C1) containing an acrylic rubber polymer as the rubber polymer (also referred to as "acrylic graft copolymer (C1)") and a graft copolymer (C2) containing a diene rubber polymer as the rubber polymer (also referred to as "diene graft copolymer (C2)"). As a result, the resin composition according to this embodiment has even higher impact strength and even better color development.

[0048] The proportion of diene-based graft copolymer (C2) in graft copolymer (C) is preferably 2 to 80% by weight, more preferably 5 to 40% by weight, and even more preferably 7 to 20% by weight. This results in the resin composition according to this embodiment having even higher impact strength and even better color development. Furthermore, because the upper limit of this proportion is as described above, the resin composition according to this embodiment has excellent weather resistance.

[0049] From the viewpoint of achieving even higher impact strength, superior color development, and better resistance to whitening in hot water, it is preferable that the graft copolymer (C) contains butadiene units. The butadiene unit content in the graft copolymer (C) is preferably 0.5 to 40% by weight, more preferably 1.0 to 30% by weight, and even more preferably 2.0 to 25% by weight.

[0050] <Vinyl cyanide compound> Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile. These may be used individually or in combination of two or more. Of these, acrylonitrile is preferred.

[0051] <Aromatic vinyl compounds> Examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, p-isopropylstyrene, o-chlorostyrene, p-chlorostyrene, and dichlorostyrene. These may be used individually or in combination of two or more. Of these, styrene is preferred.

[0052] <(meth)acrylate alkyl ester> Examples of the alkyl (meth)acrylate esters include alkyl (meth)acrylate esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate; aromatic ring-containing (meth)acrylates such as phenoxyethyl (meth)acrylate and benzyl (meth)acrylate; hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate; glycidyl (meth)acrylates such as glycidyl (meth)acrylate and glycidylalkyl (meth)acrylate; and alkoxyalkyl (meth)acrylates. These may be used individually or in combination of two or more.

[0053] From the viewpoint of further increasing impact strength, it is preferable that the particle size distribution of the graft copolymer (C) is multi-peaked. The presence or absence of multimodality in the particle size distribution of graft copolymer (C) can be confirmed by measuring the particle size distribution of the graft copolymer (C) in its latex state using a volume-based particle size measuring device. For example, the particle size distribution can be measured in the latex state using a particle size analyzer (Nikkiso Co., Ltd., Nanotracwave) with a wavelength of 546 nm and light scattering. Graft copolymers (C) with a multimodal particle size distribution can be obtained by mixing two or more graft copolymers with different volume-average particle sizes. Furthermore, the volume-average particle size of the graft copolymer can be controlled by the type and amount of polymerization initiators, chain transfer agents, redox agents, emulsifiers, etc., as well as the polymerization temperature and polymerization time. Furthermore, when mixing two or more graft copolymers with different volume-average particle diameters, it is possible to confirm that the particle diameter distribution of graft copolymer (C) is multimodal by checking if the difference between the volume-average particle diameter of one graft copolymer and the volume-average particle diameter of the other graft copolymers is 100 nm or more. In the graft copolymer (C), the difference between the volume-average particle diameter of one graft copolymer and the volume-average particle diameter of the other graft copolymer is preferably 100 nm or more, and more preferably 100 nm or more and 2000 nm or less.

[0054] The graft copolymer (C) may also be core-shell type polymer particles consisting of a shell layer and one or more core layers. The shell layer refers to the polymer layer located on the surface side of the polymer particle, and is also called the graft layer. The core layer refers to the polymer layer located inside the polymer particle, and is composed of a rubbery polymer. The core layer may be a single layer or may consist of two or more layers with different monomer compositions. The innermost core layer is sometimes called the seed particle. The shell layer covers the surface of the core layer, but is not limited to covering the entire surface of the core layer; it is sufficient to cover at least a part of the surface of the core layer.

[0055] In the resin composition according to this embodiment, the proportion of component (C) is preferably 10 to 40% by weight, more preferably 15 to 35% by weight, and even more preferably 20 to 30% by weight, based on a total weight of 100% by weight of components (A), (B), (C), and (D). As a result, the resin composition according to this embodiment has even higher impact strength and even better color development, resistance to whitening in hot water, and processability.

[0056] <Method for producing graft copolymer (C)> While known methods can be used to produce the graft copolymer (C), and are not particularly limited, it is preferable to obtain it by a water-based polymerization method such as emulsion polymerization or suspension polymerization, from the viewpoint of ease of recovery, low odor of the polymer, handling properties, blocking resistance, and economic efficiency. Of these, emulsion polymerization is more preferable from the viewpoint of dispersibility of the graft copolymer (C) in the vinyl chloride resin. In polymerization using water as a medium, a latex containing graft copolymer (C) (also called "graft copolymer (C) latex") is obtained.

[0057] In emulsion polymerization, an emulsifier is used. Conventional emulsifiers can be used, including anionic emulsifiers such as polyoxyalkylene ether phosphate salts, fatty acid salts, alkyl sulfate salts, alkylbenzene sulfonates, alkyl phosphate salts, and sulfosuccinate diesters; cationic emulsifiers such as alkylamine salts; and nonionic emulsifiers such as polyoxyethylene alkyl ethers and polyoxyethylene fatty acid esters. In particular, anionic emulsifiers are preferred in terms of polymerization stability, fatty acid salts and sulfosuccinate diester salts are more preferred, and semi-hydrogenated beef tallow fatty acid potassium and dioctyl sulfosuccinate sodium are even more preferred. Furthermore, from the viewpoint of reducing residual impurities and improving resistance to whitening in hot water, polyoxyalkylene ether phosphate salts are preferred. These may be used individually, or two or more may be used in combination. Furthermore, ethylenediaminetetraacetate disodium salt, formaldehyde sulfoxylate sodium, ferrous sulfate, etc. may be used as co-catalysts for polymerization, sodium sulfate, etc. may be used as viscosity modifiers for latex, and sodium hydroxide, etc. may be used as pH adjusters.

[0058] In emulsion polymerization, radical polymerization agents are used. These radical polymerization agents may include organic hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, and t-butyl peroxylaurate; redox initiators formed by combining an oxidizing agent (an organic hydroperoxide) with a reducing agent such as sulfites, bisulfites, thiosulfates, metalloid salts, or sodium formaldehyde sulfoxylate; persulfates such as potassium persulfate and ammonium persulfate; azo compounds such as azobisisobutyronitrile, dimethyl-2,2'-azobisisobutyrate, and 2-carbamoyl azaisobutyronitrile; and organic peroxides such as benzoyl peroxide and lauroyl peroxide. These may be used individually or in combination of two or more. Among these, the radical polymerization agent is preferably an organic hydroperoxide, and more preferably t-butyl hydroperoxide.

[0059] The amount of radical polymerization agent used (preferably the amount of radical polymerization agent used when polymerizing the rubbery mass) is, for example, 0.01 to 5.0 parts by weight, preferably 0.1 to 3.5 parts by weight, and more preferably 0.5 to 3.0 parts by weight, per 100 parts by weight of monomer used. If the amount of radical polymerization agent is large, the weight-average molecular weight tends to decrease, and if the amount of radical polymerization agent is small, the weight-average molecular weight tends to increase.

[0060] In emulsion polymerization, a chain transfer agent may be used as needed. Examples of chain transfer agents include mercaptans such as octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, and t-tetradecyl mercaptan; hydrocarbon salts such as tetraethyl thiuram sulfide, carbon tetrachloride, ethylene bromide, and pentanephenylethane; terpenes, acrolein, methacrolein, allyl alcohol, 2-ethylhexylthioglycol, and α-methylstyrene dimer. Among these, the chain transfer agent is preferably a mercaptan, and more preferably t-dodecyl mercaptan. These may be used individually or in combination of two or more.

[0061] The amount of chain transfer agent used (preferably the amount of chain transfer agent used during polymerization of the rubbery mass) is, for example, 0 to 3 parts by weight, preferably 0.001 to 2.5 parts by weight, more preferably 0.01 to 2 parts by weight, and even more preferably 0.1 to 1.5 parts by weight, per 100 parts by weight of monomer. If the amount of chain transfer agent is too high, the impact strength may deteriorate.

[0062] The polymerization time in emulsion polymerization can be adjusted depending on the monomers, emulsifiers, radical polymerizers, and chain transfer agents used as needed, and their amounts, but is for example 1 to 50 hours, preferably 5 to 24 hours. The polymerization temperature can be adjusted depending on the monomers, emulsifiers, radical polymerizers, and chain transfer agents used as needed, and their amounts, but is for example 10°C to 90°C, preferably 40°C to 80°C.

[0063] The weight-average molecular weights of the graft copolymer (C), the rubbery mass of the trunk, and the branch portions can be adjusted by adjusting the ratio of the monomers that constitute each. Furthermore, these weight-average molecular weights can also be adjusted by adjusting the amount of radical polymerization agent and, if necessary, chain transfer agent used, as well as the polymerization temperature and polymerization time.

[0064] In the production of core-shell type graft copolymer (C) by emulsion polymerization, specifically, first, latex particles corresponding to the core layer are produced by emulsion polymerization, and then monomer components for the shell layer and polymerization initiators are added to the latex to polymerize the monomer components. As an efficient method for producing relatively large-particle core-shell type graft copolymers (C) using conventional emulsion polymerization, a method is known in which water-soluble electrolytes or acid group-containing copolymer latex are added to enlarge the particles before or during graft polymerization. Methods for enlarging particles using water-soluble electrolytes are disclosed in Japanese Patent Publication No. 4-170458 and Japanese Patent Publication No. 60-192754, among others. Methods for enlarging particles using acid group-containing copolymer latex are disclosed in Japanese Patent Publication No. 10-245468 and Japanese Patent Publication No. 8-12704, among others.

[0065] A method for producing graft copolymer (C) preferably includes a coagulation step in which the latex of the graft copolymer (C) is coagulated with a coagulant, the coagulated graft copolymer (C) is washed with water (such as deionized water), and the washed graft copolymer (C) is dried.

[0066] The coagulant can be any substance that has the property of coagulating and solidifying the graft copolymer (C) in the latex of the graft copolymer (C). Examples of coagulants include inorganic acids, inorganic acid salts, organic acids, organic acid salts, and polymer coagulants. One of these coagulants may be used alone, or two or more may be used in combination. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. Examples of inorganic salts include alkali metal halides such as sodium chloride, potassium chloride, lithium chloride, sodium bromide, potassium bromide, lithium bromide, potassium iodide, and sodium iodide; alkali metal sulfides such as potassium sulfate and sodium sulfate; ammonium sulfate; ammonium chloride; alkali metal nitrides such as sodium nitrate and potassium nitrate; calcium chloride, ferrous sulfate, magnesium sulfate, zinc sulfate, copper sulfate, barium chloride, ferrous chloride, ferric chloride, magnesium chloride, ferric sulfate, aluminum sulfate, potassium alum, and iron alum. Examples of organic acids include acetic acid and formic acid. Examples of organic acid salts include calcium acetate, magnesium acetate, sodium acetate, sodium formate, and calcium formate.

[0067] Among the coagulants mentioned above, monovalent or divalent inorganic salts such as sodium chloride, potassium chloride, sodium sulfate, ammonium chloride, calcium chloride, magnesium chloride, magnesium sulfate, and barium chloride; and monovalent or divalent inorganic acids such as hydrochloric acid and sulfuric acid are preferably used from the viewpoint of coagulation ability and availability. Furthermore, from the viewpoint of resistance to whitening in hot water, calcium chloride and calcium acetate are particularly desirable as the coagulant.

[0068] In the aforementioned solidification step, the washing can reduce the amount of residual ions (such as chloride ions) in the graft copolymer (C) that originate from the coagulant. From the viewpoint of further improving resistance to hot water whitening, the residual ion content of the graft copolymer (C) is preferably 0 ppm or more and 300 ppm or less. The upper limit of the residual ion content is preferably 270 ppm or less, and more preferably 250 ppm or less. The amount of residual ions can be measured using a fluorescent X-ray device or similar equipment. The amount of residual chloride ions can be defined as the amount of residual ions, and this amount of residual chloride ions can be measured using a fluorescent X-ray device or similar equipment.

[0069] Examples of methods for producing a resin composition containing a graft copolymer with a multimodal particle size distribution include the following methods. (a) A method of obtaining a resin composition by dry blending two or more graft copolymers with different volume-average particle sizes (for example, mixing two or more graft copolymers with different volume-average particle sizes obtained in a solidification step) to obtain a graft copolymer (C) with a multimodal particle size distribution, and mixing the graft copolymer (C) with other components such as component (A). (b) A method in which two or more graft copolymer latexes with different volume-average particle sizes are mixed, the mixed latex is solidified in the solidification step, and the resulting graft copolymer (C) is mixed with other components such as component (A) to obtain a resin composition. (c) A method for obtaining a resin composition by mixing two or more graft copolymers with different volume-average particle sizes together with other components such as component (A).

[0070] <<Copolymer (D)>> The resin composition according to this embodiment contains a copolymer (D) comprising aromatic vinyl compound units and vinyl cyanide compound units. As a result, the resin composition according to this embodiment has high impact strength and elastic modulus, as well as excellent color development, resistance to whitening in hot water, and processability.

[0071] The aromatic vinyl compound constituting the copolymer (D) is not particularly limited, but examples include styrene, α-methylstyrene, p-methylstyrene, p-isopropylstyrene, o-chlorostyrene, p-chlorostyrene, and dichlorostyrene. One of these may be used alone, or two or more may be used in combination. Of these, styrene and α-methylstyrene are preferred, and styrene is particularly preferred.

[0072] The vinyl cyanide compound constituting the copolymer (D) is not particularly limited, but examples include acrylonitrile and methacrylonitrile. One of these may be used alone, or two may be used in combination. Of these, acrylonitrile is preferred.

[0073] The copolymer (D) may be a copolymer composed only of aromatic vinyl compound units and vinyl cyanide compound units, but it may also be a copolymer that further contains other copolymerizable vinyl compound units in addition to these two types of units.

[0074] Other copolymerizable vinyl compounds are not particularly limited, but examples include alkyl (meth)acrylates having C1-C12 alkyl groups such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; maleimide compounds such as maleimide, N-phenylmaleimide, and cyclohexylmaleimide; and acrylic acid, methacrylic acid, isopropenylnaphthalene, acrylamide, methacrylamide, glycidyl acrylate, and glycidyl methacrylate. These may be used individually or in combination of two or more.

[0075] The content of the aromatic vinyl compound in the copolymer (D) is not particularly limited, but is preferably 60 to 85% by weight, and more preferably 65 to 80% by weight. The content of the vinyl cyanide compound is also not particularly limited, but is preferably 15 to 40% by weight, and more preferably 20 to 35% by weight. The content of the other copolymerizable vinyl compound is also not particularly limited, but is preferably 0 to 25% by weight, and more preferably 0 to 15% by weight.

[0076] Specific examples of the copolymer (D) include styrene-acrylonitrile copolymer, α-methylstyrene-acrylonitrile copolymer, styrene-α-methylstyrene-acrylonitrile copolymer, styrene-maleimide-acrylonitrile copolymer, styrene-α-methylstyrene-maleimide-acrylonitrile copolymer, styrene-acrylonitrile-methyl methacrylate copolymer, α-methylstyrene-acrylonitrile-methyl methacrylate copolymer, styrene-α-methylstyrene-acrylonitrile-methyl methacrylate copolymer, styrene-maleimide-acrylonitrile-methyl methacrylate copolymer, and styrene-α-methylstyrene-maleimide-acrylonitrile-methyl methacrylate copolymer. These may be used individually or in combination of two or more.

[0077] In the resin composition according to this embodiment, the proportion of component (D) is preferably 8 to 30% by weight, and more preferably 12 to 25% by weight, relative to the total weight of components (A), (B), (C), and (D) of 100% by weight. As a result, the resin composition according to this embodiment has even higher impact strength and elastic modulus, and is even better in terms of color development, resistance to whitening in hot water, and processability.

[0078] <<Additives>> As described above, the resin composition according to this embodiment may contain additives, and examples of such additives, in addition to those mentioned above, include matting agents, flame retardants, mold release agents, antistatic agents, antibacterial and antifungal agents. Examples of such pigments include carbon black. Additives may be used individually or in combination of two or more types.

[0079] The method for mixing materials to produce the resin composition according to this embodiment is not particularly limited, and existing methods such as mechanical mixing using known equipment such as a Banbury mixer, roll mill, or twin-screw extruder can be used.

[0080] <<Applications>> The resin composition according to this embodiment is a resin composition for cap stock. Capstock is useful, for example, as a protective layer for PVC building products (e.g., PVC siding, window frames, fences, decks, and gutters). Methods for molding cap stocks from resin compositions include extrusion molding, compression molding, blow molding, calendering, vacuum forming, and injection molding, but extrusion molding is preferred in terms of manufacturing process and cost. Extrusion molding can be performed by melting and extruding material from a die of the desired shape and dimensions, such as a T-die or ring-die, and then cooling it. It is also possible to stretch the material uniaxially or biaxially simultaneously with or after extrusion.

[0081] Methods for manufacturing a cap stock-attached substrate include, for example, a method of co-extruding a resin composition for the cap stock and a resin composition for the substrate, a method of heating the substrate and the cap stock in contact under pressure, and a method of bonding the substrate and the cap stock with an adhesive.

[0082] Examples of resins included in the aforementioned substrate resin composition include polyvinyl chloride (PVC) and other vinyl chloride resins, high-impact polystyrene (HIPS), polypropylene (PP), and acrylonitrile-butadiene-styrene resin (ABS resin).

[0083] The thickness of the cap stock is not particularly limited, but is, for example, 0.05 to 3 mm, more specifically 0.1 to 1.5 mm, and even more specifically 0.2 to 1.0 mm.

[0084] Furthermore, the present invention is not limited to the embodiments described above. Nor is it limited by the effects and advantages described above. Moreover, the present invention can be modified in various ways without departing from the spirit of the invention.

[0085] [Disclosure items] Each of the following items is a disclosure of a preferred embodiment.

[0086] [Item 1] Vinyl chloride resin (A), A block copolymer (B) comprising a polymer block (B1) containing acrylic acid ester units and a polymer block (B2) containing methacrylic acid ester units, A graft copolymer (C) obtained by polymerizing a rubbery polymer with a monomer component containing one or more monomers selected from the group consisting of vinyl cyanide compounds, aromatic vinyl compounds, and alkyl (meth)acrylate esters, Copolymer (D) containing aromatic vinyl compound units and vinyl cyanide compound units A resin composition for cap stock containing [the specified ingredient]. [Item 2] The resin composition for cap stock described in item 1, wherein the residual ion content of the graft copolymer (C) is 300 ppm or less. [Item 3] A resin composition for cap stock according to item 1 or 2, wherein the particle size distribution of the graft copolymer (C) is multimodal. [Item 4] A resin composition for cap stock according to any one of items 1 to 3, wherein the graft copolymer (C) comprises a graft copolymer (C1) containing an acrylic rubber polymer as the rubber polymer, and a graft copolymer (C2) containing a diene rubber polymer as the rubber polymer. [Item 5] The resin composition for cap stock described in item 4, wherein the proportion of diene-based graft copolymer (C2) in graft copolymer (C) is 5 to 40% by weight. [Item 6] A resin composition for cap stock according to any one of items 1 to 5, wherein the proportion of polymer blocks (B2) in the block copolymer (B) is 15 to 60% by weight. [Item 7] A resin composition for cap stock according to any one of items 1 to 6, wherein the block copolymer (B) is a triblock copolymer composed of polymer block (B2) - polymer block (B1) - polymer block (B2). [Item 8] A resin composition for cap stock according to any one of items 1 to 7, wherein the weight-average molecular weight of the block copolymer (B) is 30,000 to 300,000. [Item 9] A resin composition for cap stock as described in any one of items 1 to 8, wherein, based on a total weight of 100% of components (A), (B), (C), and (D), component (A) accounts for 20-60% by weight, component (B) accounts for 8-30% by weight, component (C) accounts for 10-40% by weight, and component (D) accounts for 8-30% by weight. [Examples]

[0087] The present invention will be described in detail below with reference to examples, but these examples are not intended to limit the present invention. In the examples, unless otherwise specified, "parts" refers to "parts by weight" when referring to quantity.

[0088] The physical properties were measured according to the following method.

[0089] (Weight ratio of each polymer block in block copolymer (B)) The weight ratio of each polymer block in block copolymer (B) was determined by 1H-NMR measurement. The measurement apparatus and conditions used for the 1H-NMR measurement are as follows: • Equipment: Bruker AVANCE NEO 700 • Deuterated solvent: Deuterated chloroform

[0090] (Weight-average molecular weight (Mw) of component (B)) The block copolymer (B) to be measured was dissolved in chloroform, and the soluble portion was filtered through a PTFE disposable filter with a pore size of 0.45 μm. The weight-average molecular weight was then determined by GPC measurement using the filtrate under the following conditions. GPC measurement device: Shimadzu Corporation High-Performance Liquid Chromatograph 20A System Columns: Showa Denko KG 4A (1 piece), K-806M (2 pieces) Sample concentration: 1 mg / ml Free solution: Chloroform solution Free liquid flow rate: 1.0ml / min Sample injection volume: 100 μL Analysis time: 30 minutes Standard sample: Standard polystyrene

[0091] (Amount of residual ions in component (C)) 4.0 g of each component (C) was weighed out, and the amount of chlorine element (residual chloride ions) (residual ions) was measured using the energy-dispersive X-ray fluorescence spectrometer "SPECTRO XEPOS" manufactured by Rigaku Denki Kogyo Co., Ltd. The obtained measurement values ​​are shown in ppm in Table 4 below. Furthermore, the total amount of residual ions in component (C) was calculated from the residual ion amounts and blending ratios of each component. The calculated values ​​are shown in Tables 5 and 6 below.

[0092] (Presence or absence of multimodality in the particle size distribution of component (C)) The presence or absence of multimodality in the particle size distribution of component (C) was confirmed by the method described above. The presence or absence of multimodality is shown in Tables 5 and 6 below.

[0093] (Manufacturing of PVC Blend 1) PVC Blend 1 was prepared with the formulation shown in Table 1 below. Specifically, first, all materials except the Sn stabilizer were placed in a container and stirred at low speed. Next, the Sn stabilizer (liquid) was slowly added to the container and stirred at high speed. Then, the temperature was raised to 110°C, and after the heating stopped, it was cooled to 80°C. Note that "phr" means "parts by weight".

[0094] [Table 1]

[0095] (Manufacturing of PVC Blend 2) PVC Blend 2 was prepared in the same manner as PVC Blend 1, except that the composition was as shown in Table 2 below.

[0096] [Table 2]

[0097] (Manufacturing example B-1: Manufacturing of block copolymer (B-1)) A three-way stopcock was attached to a 2L three-necked flask, and the inside was purged with nitrogen. Then, 1154g of toluene and 24.9g of 1,2-dimethoxyethane were added while stirring at room temperature. Subsequently, 37.8g of a toluene solution containing 19.0 mmol of isobutylbis(2,6-di-butyl-4-methylphenoxy)aluminum was added, followed by 2.12g of a cyclohexane solution of sec-butyllithium (s-BuLi sol) containing 3.62 mmol of sec-butyllithium (s-BuLi). Next, 39.4 g of methyl methacrylate (MMA) was added. The reaction solution was initially yellow, but became colorless after stirring at room temperature for 60 minutes. Next, the internal temperature of the polymerization solution was cooled to -30°C, and 105.3 g of n-butyl acrylate (BA) was added dropwise over 2 hours. After the addition was complete, the mixture was stirred at -30°C for 5 minutes. Furthermore, 65.8g of methyl methacrylate (MMA) was added to this mixture, and it was stirred overnight at room temperature. After adding 12.2 g of methanol to stop the polymerization reaction, the resulting reaction solution was poured into 15 kg of methanol to precipitate a white precipitate. The white precipitate was then collected and dried to obtain acrylic block copolymer (B-1). The proportion of polymer blocks (B1) in block copolymer (B-1) was 50% by weight, and the proportion of polymer blocks (B2) was also 50% by weight. The weight-average molecular weight (Mw) of block copolymer (B-1) is shown in Table 3 below.

[0098] (Manufacturing examples B-1 to B-4: Manufacturing of block copolymers (B-2 to B-4)) Except for the changes in the quantities shown in Table 3 below, block copolymers (B-2 to B-4) were prepared using the same method as the method for producing block copolymer (B-1) described above. The proportion of polymer blocks (B1) in the block copolymer (B-2) was 69% by weight, and the proportion of polymer blocks (B2) was 31% by weight. The proportion of polymer blocks (B1) in the block copolymer (B-3) was 60% by weight, and the proportion of polymer blocks (B2) was 40% by weight. The proportion of polymer block (B1) in the block copolymer (B-4) was 80% by weight, and the proportion of polymer block (B2) was 20% by weight. The weight-average molecular weight (Mw) of each block copolymer (B-2 to B-4) is shown in Table 3 below.

[0099] Furthermore, all block copolymers (B-1 to B-4) are triblock copolymers composed of polymer block (B2) - polymer block (B1) - polymer block (B2).

[0100] [Table 3]

[0101] (Manufacturing example C1-1: Manufacturing of acrylic graft copolymer (C1-1)) 180 parts of pure water were charged into the polymerization reactor, the reactor was degassed, and nitrogen was purged before 0.40 parts of sodium palmitate were added. The temperature was raised to 45°C, and 0.01 parts of disodium ethylenediaminetetraacetate, 0.0015 parts of ferrous sulfate (heptahydrate), and 0.2 parts of sodium formaldehyde sulfoxylate were added. A mixture of 45 parts of butyl acrylate, 0.5 parts of allyl methacrylate, and 0.017 parts of cumene hydroperoxide was added dropwise as the first monomer for 2 hours, and after the dropwise addition was complete, the mixture was stirred at 45°C for 1 hour. 0.1 parts of sodium palmitate were added at 10, 20, 40, and 60 minutes after addition. Subsequently, the mixture was stirred for 1 hour after the dropwise addition was complete to obtain an acrylic rubber polymer. One hour after the end of dropwise addition, the temperature was raised to 70°C. Then, 10 parts of acrylonitrile, 40 parts of styrene, and 0.2 parts of t-butyl peroxide were continuously added dropwise for 3 hours as the second monomer (MA). After the end of dropwise addition, the mixture was stirred for 1 hour to complete the polymerization. The polymerization conversion rate was 99%. The volume-average particle size of the latex of the obtained acrylic graft copolymer was 140 nm. Acrylic graft copolymer latex was solidified by adding hydrochloric acid. The solidified slurry was heat-treated and dehydrated to obtain acrylic graft copolymer powder (C1-1).

[0102] (Manufacturing Example C1-2 (Manufacturing Example AIM-0): Manufacturing of acrylic graft copolymer (C1-2)) In a pressure polymerizer equipped with a stirrer, 100 parts of pure water and 0.014 parts of sodium polyoxyethylene alkyl ether phosphate as a surfactant were added while blowing in nitrogen. Next, while stirring the added raw materials, the oxygen inside the pressure polymerizer was thoroughly removed by purging the gas inside with nitrogen. Then, the temperature of the solution in the pressure vessel was raised to 50°C. Subsequently, 8.5 parts of butyl acrylate (BA), 0.04 parts of allyl methacrylate, and 0.002 parts of t-butyl hydroperoxide (BHP) were added to the pressure vessel all at once. Then, 0.002 parts of ethylenediaminetetraacetate disodium salt (EDTA), 0.0012 parts of ferrous sulfate, and 0.05 parts of sodium formaldehyde sulfoxylate (SFS) were added to the pressure vessel. Polymerization was then carried out for 1 hour. Subsequently, a mixture of 0.68 parts of sodium polyoxyethylene alkyl ether phosphate, 64.5 parts of BA, 0.32 parts of allyl methacrylate, and 0.02 parts of BHP, which are surfactants, was added to the pressure vessel over 210 minutes. Then, the reaction solution in the pressure polymerization reactor was maintained at 50°C for 45 minutes to carry out polymerization and obtain an aqueous latex containing an elastic material. Next, 73 parts of the solid component of the elastic material (50°C) and 150 parts of pure water (50°C) were added to a glass reactor. The glass reactor was equipped with a thermometer, a stirrer, a reflux condenser, a nitrogen inlet, and a monomer addition device. The added raw materials were stirred at 50°C while replacing the gas in the glass reactor with nitrogen. Next, a mixture of 25.3 parts of methyl methacrylate (MMA) and 1.7 parts of BA, as monomer components, was added to the glass reactor over 1 hour. Simultaneously with the addition of the monomer components (i.e., MMA and BA), the addition of 0.0125 parts of BHP to the glass reactor was started. After the addition of BHP was completed, the temperature of the reaction solution in the glass reactor was maintained at 50°C for 1 hour to carry out polymerization, obtaining an aqueous latex containing a rubber-containing graft copolymer. The volume-average particle size of the rubber-containing graft copolymer contained in the obtained aqueous latex was 200 nm. Calcium chloride was added to the latex of an acrylic graft copolymer and allowed to solidify. After heat treatment and dehydration of the solidified slurry, it was washed with 350 parts by weight of deionized water per 100 parts by weight of solids of the acrylic graft copolymer, and then dehydrated and dried again to obtain an acrylic graft copolymer powder (C1-2).

[0103] (Manufacturing examples C1-3~6: Manufacturing of acrylic graft copolymers (C1-3~6)) Except for using ion-exchanged water (washing water) at concentrations of 50 parts by weight, 150 parts by weight, 500 parts by weight, and 1000 parts by weight, respectively, per 100 parts by weight of solids in the acrylic graft copolymer, powders of the acrylic graft copolymer (C1-3 to C6) were obtained in the same manner as in Production Example C1-2 (Production Example AIM-0).

[0104] (Manufacturing of acid group-containing latex (S)) The acid group-containing latex (S) used in the production of the acrylic butadiene graft copolymer (C2) described later was obtained as follows. Specifically, a latex containing acid group copolymer with a composition of styrene / butyl acrylate / methacrylic acid = 55 / 30 / 15 was synthesized by the emulsion polymerization method described in Japanese Patent Publication No. 8-134316, and an acid group containing latex (S) with a volume-average particle size of 200 nm was obtained.

[0105] (Manufacturing example C2: Manufacturing of acrylic butadiene graft copolymer (C2)) 200 parts of water were charged into a pressure polymerizer (100 L), the polymerizer was degassed, and the chamber was purged with nitrogen. Then, 60 parts of butadiene, 40 parts of butyl acrylate, 0.4 parts of tripotassium phosphate aqueous solution, and 2 parts of sodium oleate were charged. The temperature was raised to 45°C, and 0.2 parts of sodium formaldehyde sulfoxylate and 0.01 parts of paramenthane hydroperoxide were added to start polymerization. 0.01 parts of paramenthane hydroperoxide was added as needed, and polymerization was terminated after 12 hours to obtain a rubbery polymer latex. The polymerization conversion rate of the obtained latex was 97%, and the volume-average particle size was 80 nm. Fifty parts of the above rubbery polymer were adjusted to a latex with a solid content of 33% and a pH of 9 or higher. 1.8 parts of acid group-containing latex (S) were added at 70°C and stirred for 3 hours to obtain a rubbery polymer latex with a volume-average particle size of 650 nm. Subsequently, 0.004 parts of disodium ethylenediaminetetraacetate, 0.001 parts of ferrous sulfate (heptahydrate), and 0.2 parts of sodium formaldehyde sulfoxylate were added. A mixture of 10 parts of acrylonitrile, 40 parts of styrene, and 0.1 parts of t-butyl hydroperoxide, as monomer components, was continuously added over 5 hours. After the completion of dropwise addition, stirring was performed for 2 hours to obtain an acrylic butadiene-based graft copolymer latex. The polymerization conversion rate was 99%. A phenolic antioxidant was added to the latex of an acrylic butadiene graft copolymer, and then hydrochloric acid was added to allow it to solidify. The solidified slurry was heat-treated and dehydrated to obtain a powder of acrylic butadiene graft copolymer (C2).

[0106] (Manufacturing example C3: Manufacturing of acrylic graft copolymer (C3)) In a glass reactor equipped with a thermometer, stirrer, reflux condenser, nitrogen inlet, and monomer and emulsifier addition device, 180 parts by weight of deionized water and 0.023 parts by weight of a 0.5% by weight sodium dioctyl sulfosuccinate aqueous solution were charged, and the temperature was raised to 60°C while stirring in a nitrogen atmosphere. A mixture of 4.75 parts by weight of methyl methacrylate (hereinafter referred to as MMA), 0.25 parts by weight of butyl acrylate (hereinafter referred to as BA), 0.25 parts by weight of allyl methacrylate, and 0.015 parts by weight of cumene hydroperoxide was added. Next, 0.0033 parts by weight of a mixture of disodium ethylenediaminetetraacetate and ferrous sulfate dissolved in deionized water in a 4:1 ratio to a concentration of 0.5% by weight was charged, along with 0.04 parts by weight of a 5% by weight sodium formaldehyde sulfoxylate solution. The mixture was stirred for 60 minutes to form seed particles with a polymerization conversion rate of 97%. Then, 0.005 parts by weight of cumene hydroperoxide was added, and a mixture of 42.5 parts by weight of BA and 0.2 parts by weight of allyl methacrylate was added over 120 minutes. During the addition process, 0.005 parts by weight of cumene hydroperoxide was added depending on the degree of polymerization. After the addition, the mixture was stirred for 60 minutes while raising the temperature to 65°C to form the first core layer with a polymerization conversion rate of 98%. To this, 0.0027 parts by weight of a mixture of disodium ethylenediaminetetraacetate and ferrous sulfate in a 4:1 ratio, dissolved in deionized water to a concentration of 0.5% by weight, was added. A mixture of 2.5 parts by weight of BA, 0.06 parts by weight of allyl methacrylate, and 0.0063 parts by weight of cumene hydroperoxide was added over 10 minutes. After addition, the mixture was stirred for 60 minutes to form a second core layer with a volume-average particle size of 400 nm and a polymerization conversion rate of 99%. To this, 0.16 parts by weight of 5% by weight of sodium formaldehyde sulfoxylate was added. A mixture of 12.7 parts by weight of acrylonitrile (hereinafter referred to as AN), 36.3 parts by weight of styrene (hereinafter referred to as ST), 1.0 part by weight of BA, 0.12 parts by weight of t-dodecyl mercaptan, and 0.2 parts by weight of t-butyl hydroperoxide was added over 180 minutes. After addition, 0.0051 parts by weight of a mixture of disodium ethylenediaminetetraacetate and ferrous sulfate dissolved in deionized water in a 4:1 ratio to a concentration of 0.5% by weight was added, along with 0.05 parts by weight of 5% sodium formaldehyde sulfoxylate, and the mixture was stirred for 10 minutes. Then, 0.05 parts by weight of t-butyl hydroperoxide was added and the mixture was stirred for 20 minutes. Subsequently, 0.05 parts by weight of t-butyl hydroperoxide was added and the mixture was stirred for 40 minutes to form a shell layer with a polymerization conversion rate of 99.5%. As a result, an acrylic graft copolymer latex consisting of a core layer (seed particles, first core layer, and second core layer) and a shell layer was obtained. Calcium chloride was added to the latex of an acrylic graft copolymer and allowed to solidify. After heat treatment and dehydration of the solidified slurry, it was washed with 500 parts by weight of deionized water per 100 parts by weight of solids of the acrylic graft copolymer, and then dehydrated and dried again to obtain acrylic graft copolymer powder (C3).

[0107] The acrylic graft copolymers (C1-1 to C1-6) and acrylic graft copolymer (C3) used in the examples are graft copolymers (C1) that contain an acrylic rubber polymer as the rubber polymer. Furthermore, the acrylic butadiene-based graft copolymer (C2) used in the examples is a graft copolymer (C2) that contains a diene-based rubber polymer as the rubber polymer.

[0108] (Material information) Table 4 below shows information about the materials used to prepare the resin compositions of the examples and comparative examples.

[0109] [Table 4]

[0110] (Resin compositions of examples and comparative examples) The resin compositions of the examples and comparative examples were obtained by dry blending the materials according to the formulations shown in Tables 5 and 6 below. Note that the values ​​for each component in Tables 5 and 6 represent parts by weight. In Comparative Example 6, Sumipex LG was used instead of copolymer (D).

[0111] (Method for preparing test specimens) 250.0 g each of the resin compositions of the examples and comparative examples was kneaded at 170°C for 6 minutes using two rolls (Nippon Roll Co., Ltd., 8-inch mixing rolls) to produce sheets. Subsequently, a hot press (Shinto Metal Industry Co., Ltd., 37t press) was used to press the sheets at 180°C at 100 kgf / cm². 2 After applying pressure for 15 minutes, test specimens for Izod impact strength testing (12.7 mm × 63.5 mm × 3 mm thick), color change and hot water whitening testing (30 mm × 40 mm × 1 mm thick), and tensile testing (JIS K7133-1 type, 1 mm thick) were prepared.

[0112] (Impact resistance) The aforementioned Izod impact strength test specimens were measured at 23°C in accordance with JIS K-7110 for notched Izod impact strength (IZOD). The IZODs are shown in Tables 5 and 6 below.

[0113] (color tone) For the aforementioned color tone and hot water whitening test specimens, the reflectance YI value was measured as the color tone YI (also called "L value" or "L") using a color difference meter (model: SE-2000) manufactured by Nippon Denshoku Industries Co., Ltd., in accordance with the JIS K8722 standard. L is shown in Tables 5 and 6 below.

[0114] (Hot water whitening test) 100 mL of deionized water adjusted to 82°C was placed in a 125 mL glass bottle, and then the test specimens for the color and hot water whitening test, whose L values ​​had already been measured, were placed inside. The bottle was lightly capped, and the bottle was placed in an oven pre-set to 82°C and removed after 4 days. After adjusting at 23°C for 24 hours, the same procedure as for the color measurement was performed to measure the L value after the hot water whitening test. The difference between the L value after the hot water whitening test and the L value at the time of color measurement (before being placed in the glass bottle) was defined as ΔL2, and this value was taken as an indicator of hot water whitening ability. A large ΔL2 indicates poor hot water whitening ability. ΔL2 is shown in Tables 5 and 6 below.

[0115] (Tensile modulus of elasticity) The aforementioned tensile test specimens were subjected to tensile testing at 23°C in accordance with JIS K-7113, and the tensile modulus was measured. The tensile modulus is shown in Tables 5 and 6 below.

[0116] [Table 5]

[0117] [Table 6]

[0118] As shown in Tables 5 and 6, in Examples 1 to 17, IZOD was high, L was low, and ΔL2 was low. Furthermore, in Examples 1 to 17, sheet-like test pieces could be produced, demonstrating excellent processability. On the other hand, in Comparative Examples 1-3 and 9, which used TPU instead of block copolymer (B), and in Comparative Examples 5 and 7, which did not contain block copolymer (B), the L value was higher compared to the example. Furthermore, in Comparative Example 4, where TPU was used instead of block copolymer (B), ΔL2 was higher compared to the example. Furthermore, in Comparative Example 6, where PMMA resin was used instead of copolymer (D), the tensile modulus was lower than in Example. A lower modulus results in inferior abrasion resistance and heat resistance. Additionally, Example 6 had a higher IZOD compared to Comparative Example 6, which was prepared similarly except for the use of PMMA resin instead of copolymer (D). Furthermore, in Comparative Example 8, where TPU was used instead of block copolymer (B), the IZOD was lower compared to the example. Therefore, according to the present invention, it is possible to provide a resin composition for cap stocks containing a vinyl chloride resin that has high impact strength and elastic modulus, as well as excellent color development, resistance to whitening in hot water, and processability.

[0119] In the production of the acrylic graft copolymer component (C), when comparing Examples 6, 11-14, and 13, where the resin compositions were prepared similarly except for the amount of deionized water used during washing, the ΔL2 was lower in Examples 6, 13, and 14, where the residual ion content of component (C) was 300 ppm or less, compared to Examples 11 and 12, where the residual ion content of component (C) was 400 ppm and 305 ppm, respectively. Therefore, it can be seen that the resistance to whitening in hot water is even better when the residual ion amount of component (C) is 300 ppm or less.

[0120] In Examples 2, 5, and 7, where the proportion of polymer blocks (B1) in component (B) was less than 80% by weight, the elastic modulus was higher compared to Example 3, which was prepared in the same way except for the higher proportion of polymer blocks (B1) at 80% by weight. Therefore, it can be seen that having this ratio of less than 80% by weight results in an even higher modulus of elasticity. As a result, it can be seen that the material has excellent wear resistance and heat resistance.

Claims

1. Vinyl chloride resin (A), A block copolymer (B) comprising a polymer block (B1) containing acrylic acid ester units and a polymer block (B2) containing methacrylic acid ester units, A graft copolymer (C) obtained by polymerizing a rubbery polymer with a monomer component containing one or more monomers selected from the group consisting of vinyl cyanide compounds, aromatic vinyl compounds, and alkyl (meth)acrylate esters, Copolymer (D) containing aromatic vinyl compound units and vinyl cyanide compound units A resin composition for cap stock containing [the specified ingredient].

2. The resin composition for cap stock according to claim 1, wherein the residual ion content of the graft copolymer (C) is 300 ppm or less.

3. The resin composition for cap stock according to claim 1 or 2, wherein the particle size distribution of the graft copolymer (C) is multimodal.

4. The resin composition for cap stock according to claim 1 or 2, wherein the graft copolymer (C) comprises a graft copolymer (C1) containing an acrylic rubber polymer as the rubber polymer, and a graft copolymer (C2) containing a diene rubber polymer as the rubber polymer.

5. The resin composition for cap stock according to claim 4, wherein the proportion of diene-based graft copolymer (C2) in graft copolymer (C) is 5 to 40% by weight.

6. The resin composition for cap stock according to claim 1 or 2, wherein the proportion of polymer blocks (B2) in the block copolymer (B) is 15 to 60% by weight.

7. The resin composition for cap stock according to claim 1 or 2, wherein the block copolymer (B) is a triblock copolymer composed of polymer block (B2) - polymer block (B1) - polymer block (B2).

8. The resin composition for cap stock according to claim 1 or 2, wherein the weight-average molecular weight of the block copolymer (B) is 30,000 to 300,000.

9. The resin composition for cap stock according to claim 1 or 2, wherein, based on a total of 100% by weight of components (A), (B), (C), and (D), component (A) accounts for 20 to 60% by weight, component (B) accounts for 8 to 30% by weight, component (C) accounts for 10 to 40% by weight, and component (D) accounts for 8 to 30% by weight.

Images