Vinyl chloride resin composition and molded body

Abstract

PROBLEM TO BE SOLVED: To provide a vinyl chloride resin composition that is substantially free of tin-based stabilizers and has transparency and heat resistance. SOLUTION: A vinyl chloride resin composition containing at least 100 mass parts of a vinyl chloride resin, 0.5-2.6 mass parts of an organic acid zinc salt stabilizer, and 2-5 mass parts of a bisphenol A-type epoxy resin (excluding those containing an organotin stabilizer).

Description

Vinyl chloride resin composition and molded article

[0001] The present invention relates to a vinyl chloride resin composition, and more particularly to a vinyl chloride resin composition that has excellent transparency and heat resistance even when it is substantially free of tin-based stabilizers, and a molded article thereof.

[0002] Vinyl chloride resins are used in a variety of applications because they have excellent flame retardancy, chemical resistance, mechanical stability, transparency, adhesiveness, printability, etc., and their hardness can be easily adjusted from hard to soft by adding plasticizers. However, vinyl chloride resins have insufficient stability to light and heat, and they are susceptible to decomposition due to dehydrohalogenation. Therefore, attempts have been made to incorporate various stabilizers, such as metal salts of organic acids, organotin compounds, organic phosphite compounds, epoxy compounds, β-diketone compounds, antioxidants, and ultraviolet absorbers.

[0003] In particular, many of the transparent rigid vinyl chloride resins used in various industrial products use tin-based stabilizers as stabilizers. For example, Patent Document 1 proposes a transparent rigid vinyl chloride sheet using an octyltin-based stabilizer. Furthermore, Patent Documents 2 and 3 teach that organotin-based stabilizers are preferred as heat stabilizers in rigid vinyl chloride compositions containing chlorinated vinyl chloride resins.

[0004] Japanese Patent Application Laid-Open No. 04-085338 International Publication No. 2020 / 203863 Japanese Patent Application Laid-Open No. 2022-000520

[0005] However, some organotins have been subject to restrictions under the European REACH standard, limiting their use, and therefore there is a demand for vinyl chloride resin compositions that do not contain tin-based stabilizers. In particular, for transparent rigid vinyl chloride resin compositions that have used tin-based stabilizers, there is a demand for novel vinyl chloride resin compositions that do not contain tin-based stabilizers and that are comparable in transparency and heat resistance to conventional vinyl chloride resin compositions that contain tin-based stabilizers.

[0006] Therefore, an object of the present invention is to provide a vinyl chloride resin composition that is substantially free of tin-based stabilizers and that has transparency and heat resistance.

[0007] The present inventors have conducted extensive research into stabilizers that can replace conventional tin-based stabilizers and have discovered that by using a predetermined amount of an organic acid zinc salt-based stabilizer in combination with a predetermined amount of a bisphenol A-type epoxy resin, it is possible to achieve a vinyl chloride resin composition that does not contain a tin-based stabilizer and that has transparency and heat resistance comparable to vinyl chloride resin compositions that contain conventional tin-based stabilizers. The present invention is based on this discovery. Specifically, the gist of the present invention is as follows.

[0008] [1] A vinyl chloride resin composition (excluding those containing an organotin stabilizer) comprising at least 100 parts by mass of a vinyl chloride resin, 0.5 to 2.6 parts by mass of an organic acid zinc salt stabilizer, and 2 to 5 parts by mass of a bisphenol A-type epoxy resin. [2] The vinyl chloride resin composition according to [1], wherein the organic acid zinc salt stabilizer is a zinc salt of at least one organic acid selected from the group consisting of zinc benzoate, zinc toluate, zinc 4-tert-butylbenzoate, zinc stearate, zinc laurate, zinc versatate, zinc octoate, zinc oleate, zinc palmitate, and zinc myristate. [3] The vinyl chloride resin composition according to [1] or [2], further comprising a phosphite ester compound. [4] The vinyl chloride resin composition according to any one of [1] to [3], further comprising a methyl methacrylate-butadiene-styrene copolymer. [5] The vinyl chloride resin composition according to any one of [1] to [4], further comprising a processing aid. [6] The vinyl chloride resin composition according to any one of [1] to [5], further comprising a lubricant. [7] A molded article comprising the vinyl chloride resin composition according to any one of [1] to [6].

[0009] According to the present invention, it is possible to realize a vinyl chloride resin composition that is substantially free of tin-based stabilizers and that has transparency and heat resistance comparable to conventional vinyl chloride resin compositions that contain tin-based stabilizers.

[0010] [Vinyl chloride resin composition] The vinyl chloride resin composition according to the present invention contains at least a vinyl chloride resin, an organic acid zinc salt stabilizer, and a bisphenol A-type epoxy resin, and is substantially free of an organotin stabilizer. Each component constituting the vinyl chloride resin composition according to the present invention will be described below.

[0011] <Vinyl chloride resin> Vinyl chloride resin is a -CH ２ It refers to all polymers having a group represented by -CHCl-, and examples thereof include a homopolymer of vinyl chloride, a copolymer of a vinyl chloride monomer and another monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer, and a graft copolymer in which a vinyl chloride monomer is graft copolymerized onto a polymer other than a polyvinyl chloride resin. These may be used alone or in combination of two or more, but a homopolymer of vinyl chloride is preferred.

[0012] Examples of other monomers having an unsaturated bond copolymerizable with vinyl chloride monomer include α-olefins such as ethylene, propylene, and butylene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, and butyl acrylate; aromatic vinyls such as styrene and α-methylstyrene; N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide, etc. These other monomers may be used alone or in combination of two or more.

[0013] Examples of polymers that can be graft copolymerized with vinyl chloride monomer include ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate-carbon monoxide copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, acrylonitrile-butadiene copolymer, polyurethane, chlorinated polyethylene, chlorinated polypropylene, etc. These polymers may be used alone or in combination of two or more.

[0014] The average degree of polymerization of vinyl chloride resins is usually 300 or more and 5000 or less, and may be 500 or more, more preferably 600 or more. On the other hand, from the viewpoint of moldability, it may be preferably 3000 or less, more preferably 1500 or less. If the average degree of polymerization is too low, heat resistance and the like will decrease, and if it is too high, moldability will decrease. The average degree of polymerization means the average degree of polymerization calculated from the specific viscosity in accordance with the appendix of JIS K6720-2:1999.

[0015] The polyvinyl chloride resin may be crosslinked. Examples of methods for crosslinking the polyvinyl chloride resin include a method of adding a crosslinking agent and a peroxide, a method of irradiating with an electron beam, and a method of using a water-crosslinkable material.

[0016] <Organic Acid Zinc Salt Stabilizer> The vinyl chloride resin composition according to the present invention contains an organic acid zinc salt stabilizer as a stabilizer. That is, it is substantially free of organotin stabilizers such as diorganotin oxides and sulfides, dibutyltin salts of maleic acid and maleic acid derivatives, dibutyltin salts of organic acids, and sulfur-containing organotin compounds, which have been used in conventional transparent rigid vinyl chloride resin compositions. In the present invention, "substantially free" means either that the content of organotin compounds as stabilizers is 0% by mass, or that organotin compounds are contained as unavoidable impurities but no organotin is contained as a stabilizer.

[0017] By incorporating specific amounts of an organic acid zinc salt stabilizer and a bisphenol-type epoxy resin described below, the vinyl chloride resin composition of the present invention can have transparency and heat resistance that are comparable to those of compositions using conventional tin-based stabilizers. The organic acid zinc salt stabilizer is described below.

[0018] The stabilizer used in the vinyl chloride resin composition according to the present invention is a zinc salt of an organic acid, and is different from calcium-zinc stabilizers containing a zinc salt and a calcium salt, and barium-zinc stabilizers containing a zinc salt and a barium salt. The organic acid constituting the metal salt of the organic acid in the zinc salt of an organic acid is not particularly limited, but examples thereof include organic carboxylic acids and organic phosphoric acids. Organic carboxylic acids are preferred. Examples of the organic carboxylic acid constituting the organic carboxylic acid zinc salt include, but are not limited to, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, neooctanoic acid, 2-ethylhexyl acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, isostearic acid, stearic acid, 2-hydroxystearic acid, behenic acid, montanic acid, benzoic acid, monochlorobenzoic acid, p-tert-butylbenzoic acid, dimethylhydroxybenzoic acid, 3,5-di-tert-butyl-4-hydroxybenzoic acid, octylic acid, toluic acid, dimethylbenzoic acid, ethylbenzoic acid, cumic acid, n-propylbenzoic acid, aminobenzoic acid, N,N-dimethylaminobenzoic acid, and acetoxybenzoic acid. , monovalent carboxylic acids such as salicylic acid, p-tert-octyl salicylic acid, oleic acid, elaidic acid, linoleic acid, linolenic acid, thioglycolic acid, mercaptopropionic acid, and octylmercaptopropionic acid; monoesters or monoamide compounds of divalent carboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, oxyphthalic acid, chlorophthalic acid, aminophthalic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, aconitic acid, and thiodipropionic acid; and di- or triester compounds of trivalent or tetravalent carboxylic acids such as hemimellitic acid, trimellitic acid, mellophanic acid, and pyromellitic acid.

[0019] The organic phosphoric acids are not particularly limited, but examples thereof include mono- or dioctyl phosphoric acid, mono- or didodecyl phosphoric acid, mono- or dioctadecyl phosphoric acid, mono- or di-(nonylphenyl) phosphoric acid, phosphonic acid nonylphenyl ester, and phosphonic acid stearyl ester.

[0020] Of the above organic acids, benzoic acid, toluic acid, 4-tert-butylbenzoic acid, stearic acid, lauric acid, versatic acid, octylic acid, oleic acid, palmitic acid, and myristic acid are preferred.

[0021] The zinc salt of an organic acid may be an acidic salt, a neutral salt, a basic salt, or an overbased complex in which part or all of the base of the basic salt is neutralized with carbonic acid. Furthermore, the zinc salt of an organic acid may be composed of two or more organic acids. For example, in the case of a zinc salt of a monovalent organic acid, the same organic acid may form the anionic moiety and form a salt with divalent zinc that forms the cationic moiety, or two different monovalent organic acids may form the anionic moiety and form a salt with divalent zinc that forms the cationic moiety.

[0022] The content of the organic acid zinc salt stabilizer is 0.5 to 2.6 parts by mass, and more preferably 1.1 to 2.1 parts by mass, per 100 parts by mass of the vinyl chloride resin. A blending amount of the organic acid zinc salt stabilizer of 0.5 parts by mass or more is preferred from the viewpoint of heat resistance, and a blending amount of 2.6 parts by mass or less is preferred from the viewpoint of impact resistance.

[0023] In the present invention, the heat stabilizer may include a heat stabilizer other than the above-mentioned organic acid zinc salt stabilizer, and may include, for example, known heat stabilizers such as lead-based stabilizers such as lead stearate, dibasic lead phosphite, and tribasic lead sulfate, calcium-zinc-based stabilizers, barium-zinc-based stabilizers, and barium-cadmium-based stabilizers.

[0024] <Bisphenol A Epoxy Resin> The vinyl chloride resin composition according to the present invention contains 2 to 5 parts by mass of a bisphenol A epoxy resin in combination with the organic acid zinc salt stabilizer described above. The inventors surprisingly discovered that by including a predetermined amount of a bisphenol A epoxy resin in addition to a predetermined amount of an organic acid zinc salt stabilizer, the transparency and heat resistance of the vinyl chloride resin composition are improved even without the inclusion of an organotin stabilizer. While the reason for this is unclear, it can be inferred as follows. Specifically, it is believed that the transparency of the vinyl chloride resin composition is maintained due to the relationship between the refractive index of the organic acid zinc salt stabilizer, such as zinc laurate, and the vinyl chloride resin. Furthermore, the high molecular weight and large number of constituent epoxy groups of bisphenol A epoxy resin are believed to improve the heat resistance and stability of the vinyl chloride resin composition.

[0025] The epoxy group equivalent of the bisphenol A type epoxy resin is preferably 50 g / eq. or more, and more preferably 100 to 250 g / eq. The epoxy group equivalent can be measured in accordance with JIS K 7236:2001.

[0026] The content of the bisphenol A epoxy resin is 2 to 5 parts by mass, and more preferably 2 to 4 parts by mass, per 100 parts by mass of the vinyl chloride resin. A content of bisphenol A epoxy resin of 2 parts by mass or more is preferred from the viewpoint of thermal stability, and a content of 5 parts by mass or less is preferred from the viewpoint of softening temperature.

[0027] The vinyl chloride resin composition according to the present invention may further contain an epoxy compound other than the above-mentioned bisphenol A-type epoxy resin. Examples of the epoxy compound include bisphenol F-type epoxy resin, novolac epoxy resin, hexanediol polyglycidyl ether, polypropylene glycol polyglycidyl ether, 3-methylpentanediol polyglycidyl ether, neopentyl glycol polyglycidyl ether, trimethylolpropane polyglycidyl ether, glycerin polyglycidyl ether, epoxidized animal and vegetable oils such as epoxidized soybean oil, epoxidized linseed oil, epoxidized tung oil, epoxidized fish oil, epoxidized beef tallow oil, epoxidized castor oil, and epoxidized safflower oil, epoxidized methyl-butyl-2-ethylhexyl-stearyl stearate, epoxidized polybutadiene, tris(epoxypropyl)isocyanurate, epoxidized tall oil fatty acid ester, epoxidized linseed oil fatty acid ester, vinylcyclohexene diepoxide, dicyclohexene carboxylate, and 3,4-epoxycyclohexene methylepoxycyclohexane carboxylate.

[0028] <Phosphite Compound> From the viewpoint of thermal stability, the vinyl chloride resin composition according to the present invention may contain one or more phosphite compounds. Examples of the phosphite compound include trialkyl phosphites, dialkyl phosphites, dialkyl monoallyl phosphites, alkyl allyl phosphites, monoalkyl diallyl phosphites, diallyl phosphites, and triallyl phosphites.

[0029] Among the above-mentioned phosphorous ester compounds, phosphites can be preferably used in the present invention, and examples thereof include diphenyldecyl phosphite, triphenyl phosphite, tris-nonylphenyl phosphite, tridecyl phosphite, tris(2-ethylhexyl) phosphite, tributyl phosphite, tris(dinonylphenyl) phosphite, trilauryl trithiophosphite, trilauryl phosphite, bis(neopentyl glycol)-1,4-cyclohexanedimethyl phosphite, and distearyl pentaerythritol. tridecyl-1,1,3-tris(2'-methyl-5'-tert-butyl-4'-oxyphenyl)butane diphosphite, tetra(C12-C15 mixed alkyl)4,4'-isopropylidenediphenyl phosphite, tris(4-oxy-2,5-di-tert-butylphenyl)phosphite, tris(4-oxy-3,5-di-tert-butylphenyl)phosphite, 2-ethylhexyldiphenyl phosphite, Tris(mixed mono- and di-nonylphenyl)phosphite, hydrogenated 4,4'-isopropylidenediphenol polyphosphite, diphenyl bis[4,4'-n-butylidenebis(2-tert-butyl-5-methylphenol)]thiodiethanol diphosphite, bis(octylphenyl)bis[4,4'-n-butylidenebis(2-tert-butyl-5-methylphenol)]-1,6-hexanediol diphosphite, phenyl 4,4'-isopropylidenediphenol pentaerythritol diphosphite, phenyl diisodecyl phosphite , tetratridecyl-4,4'-n-butylidenebis(2-tert-butyl-5-methylphenol)diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, tristearyl phosphite, octyldiphenyl phosphite, diphenyltridecyl phosphite, phenyldi(tridecyl)phosphite, tris(2-cyclohexylphenyl)phosphite, ditridecyldi(2-cyclohexylphenyl)hydrogenated bisphenol A diphosphite, di(2,4-di-tert-butylphenyl)cyclohexyl phosphite, 2,Examples of suitable phosphate phosphates include 4-di-tert-butylphenyl diisodecyl phosphite, tris(butoxyethoxyethyl) phosphite, poly-4,4'-isopropylidenediphenol neodol 25 alcohol phosphite, diphenyl acid phosphite, bis(2-cyclohexylphenyl) acid phosphite, bis(2,4-di-tert-butylphenyl) acid phosphite, bis(nonylphenyl) acid phosphite, dibenzyl acid phosphite, polydipropylene glycol phenyl phosphite, and 4,4'-isopropylidenediphenyl alkyl phosphite. These may be used alone or in combination of two or more.

[0030] The content of the phosphite is not particularly limited, but from the viewpoint of thermal stability, it is preferably 0.1 to 1.5 parts by mass, and more preferably 0.2 to 1.0 part by mass, per 100 parts by mass of the vinyl chloride resin.

[0031] <Rubber Polymer> From the viewpoint of impact resistance, the vinyl chloride resin composition according to the present invention may contain a rubber polymer. The rubber polymer refers to a polymer made of a rubber component having a glass transition temperature of 10°C or lower, preferably -10°C or lower, and more preferably -30°C or lower, as well as a copolymer obtained by bonding another polymer chain to the polymer made of the rubber component. Examples of rubbery polymers include SB (styrene-butadiene) copolymer, ABS (acrylonitrile-butadiene-styrene) copolymer, MBS (methyl methacrylate-butadiene-styrene) copolymer, MABS (methyl methacrylate-acrylonitrile-butadiene-styrene) copolymer, MB (methyl methacrylate-butadiene) copolymer, ASA (acrylonitrile-styrene-acrylic rubber) copolymer, AES (acrylonitrile-ethylene propylene rubber-styrene) copolymer, MA (methyl methacrylate-acrylic rubber) copolymer, MAS (methyl methacrylate-acrylic rubber-styrene) copolymer, methyl methacrylate-acrylic-butadiene rubber copolymer, methyl methacrylate-acrylic-butadiene rubber-styrene copolymer, methyl methacrylate-(acrylic-silicone IPN rubber) copolymer, and natural rubber. Among these, SB copolymer, ABS copolymer, MBS copolymer, methyl methacrylate-acrylic-butadiene rubber copolymer, methyl methacrylate-(acrylic-silicone IPN rubber) copolymer, and natural rubber are particularly preferred. These may be used alone or in combination of two or more.

[0032] The vinyl chloride resin composition according to the present invention preferably contains an MBS (methyl methacrylate-butadiene-styrene) copolymer, among the rubber polymers described above. The MBS copolymer is preferably granular with an average particle size of about 0.1 to 1.0 μm, more preferably granular with an average particle size of 0.1 to 0.5 μm.

[0033] The content of the methyl methacrylate-butadiene-styrene copolymer is preferably 2.5 to 40 parts by mass, more preferably 5 to 35 parts by mass, and even more preferably 5 to 30 parts by mass, per 100 parts by mass of the vinyl chloride resin.

[0034] <Processing Aid> From the viewpoint of moldability, it is preferable that the vinyl chloride resin composition according to the present invention further contains a processing aid. Examples of processing aids are not particularly limited, but include acrylic processing aids that are alkyl acrylate / alkyl methacrylate copolymers having a weight-average molecular weight of 100,000 to 2,000,000, specific examples include n-butyl acrylate / methyl methacrylate copolymers and 2-ethylhexyl acrylate / methyl methacrylate / butyl methacrylate copolymers. One type may be used alone, or two or more types may be used in combination.

[0035] The content of the processing aid is not particularly limited, but from the viewpoint of moldability, it is preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 3 parts by mass, per 100 parts by mass of the vinyl chloride resin.

[0036] <Lubricant> From the viewpoint of processability, the vinyl chloride resin composition according to the present invention may further contain a lubricant. Examples of lubricants include internal lubricants and external lubricants. Internal lubricants are used to reduce the flow viscosity of the molten resin during molding and prevent frictional heat generation. Specific examples include butyl stearate, lauryl alcohol, stearyl alcohol, epoxy soybean oil, glycerin monostearate, stearic acid, and bisamide. These may be used alone or in combination of two or more. External lubricants are used to improve the sliding effect between the molten resin and the metal surfaces of the mold, barrel, and the like during molding. Specific examples include paraffin wax, polyolefin wax, ester wax, and montanic acid wax. These may be used alone or in combination of two or more.

[0037] The content of the lubricant can be adjusted appropriately taking into consideration processability, but is preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 3 parts by mass, per 100 parts by mass of the vinyl chloride resin. The lubricant content within this range allows for suitable extrusion or injection molding.

[0038] Furthermore, the vinyl chloride resin composition according to the present invention may contain, as necessary and as desired, other heat stabilizers, light stabilizers, plasticizers, ultraviolet absorbers, antioxidants, fillers, and the like, within the limits of the object of the present invention.

[0039] The vinyl chloride resin composition of the present invention is particularly suitable for use as a rigid vinyl chloride resin. Here, "rigid" means that the vinyl chloride resin composition does not contain any plasticizer, or that the vinyl chloride resin composition contains a plasticizer in an amount of 10% by weight or less. When a plasticizer is contained, any of the conventionally known plasticizers used in vinyl chloride resin compositions can be used without limitation.

[0040] The vinyl chloride resin composition according to the present invention can be obtained by blending the above-mentioned components using an apparatus such as a Henschel mixer, a V-type mixer, or a ribbon blender, and kneading the blend at a temperature of 140 to 200° C. using an apparatus such as a Banbury mixer, a single-screw extruder, a twin-screw extruder, a roll, or a kneader. The obtained vinyl chloride resin compound is preferably pelletized using an appropriate pelletizing apparatus or the like.

[0041] <Molded Article> A desired molded article can be obtained from the vinyl chloride resin composition according to the present invention. The method for obtaining the molded article is not particularly limited, and conventionally known methods such as extrusion molding, injection molding, calendar molding, and press molding can be applied. It is particularly preferable to obtain a molded article by extrusion molding. Among extrusion molding methods, profile extrusion molding, which is used to obtain molded articles such as resin sashes and window frames that require high designability, requires high molding temperatures. However, according to the present invention, a molded article can be obtained from a vinyl chloride resin composition that has excellent transparency and heat resistance, even if it does not substantially contain a tin-based stabilizer.

[0042] The present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples.

[0043] <Raw materials used> (a) Vinyl chloride resin (a-1) Polyvinyl chloride "P-700 (product name)" (average degree of polymerization 700) manufactured by Shin-Etsu Chemical Co., Ltd.

[0044] (b) Stabilizers (b-1) Zinc stearate-based stabilizer "QP-2535 (trade name)" manufactured by ADEKA Corporation (b'-1) Ca-Zn-based stabilizer "RX-222 (trade name)" manufactured by ADEKA Corporation (b'-2) Tin-based stabilizer "TM-181FSJ (trade name)" manufactured by Katsuta Chemical Industry Co., Ltd.

[0045] (c) Epoxy Compounds (c-1) Adeka Cizer EP-13 (trade name) bisphenol A epoxy resin manufactured by ADEKA Corporation (epoxy equivalent: 180 to 200 g / eq.) (c'-1) O-130P (trade name) epoxidized soybean oil manufactured by ADEKA Corporation (acid value: 0.3 KOH mg / g)

[0046] (d) Rubber Polymer (d-1) Methyl methacrylate-butadiene-styrene copolymer "Kane Ace B-22 (trade name)" manufactured by Kaneka Corporation

[0047] (e) Phosphite ester compound (e-1) Diphenyldecyl phosphite "ADEKA STAB 135A (trade name)" manufactured by ADEKA Corporation

[0048] (f) Processing aid (f-1) Kane Ace PA-50 (trade name) copolymer of methyl methacrylate / butyl acrylate manufactured by Kaneka Corporation

[0049] (g) Lubricant (g-1) Lubricant "Rikemal LUB-22 (trade name)" manufactured by Riken Vitamin Co., Ltd. (a blend of "Rikemal S-100 (trade name)" manufactured by Riken Vitamin Co., Ltd. with a polymer composite ester and oxidized polyolefin wax)

[0050] Examples 1 to 14, Comparative Examples 1 to 5 Raw materials were blended so that the respective components were in the proportions shown in Tables 1 and 2, and the molten resin was extruded using a twin-screw extruder (ZSK-25) with the cylinder temperature set to 160 to 200°C, to obtain a vinyl chloride resin composition. The vinyl chloride resin compositions were subjected to the following evaluation tests (1) to (5). Furthermore, the following evaluation tests (6) and (7) were performed using blends in which the raw materials were blended in the proportions shown in Tables 1 and 2. The evaluation results were as shown in Table 1 (Examples) and Table 2 (Comparative Examples). A reference example was prepared using a conventional tin-based stabilizer.

[0051] <Evaluation Methods> In this specification, the manufacturing methods, evaluation methods and raw materials of the test pieces used in the examples and comparative examples are as follows.

[0052] (1) Specific Gravity Specific gravity was measured in accordance with JIS K7112-1 using a 1 mm thick press sheet as a test piece.

[0053] (2) Impact resistance (Charpy impact strength) In accordance with JIS K 7111, a 4 mm thick test piece (edgewise method, 4 mm thick single notch) was used to measure the Charpy impact strength under the test conditions of JIS K 7111-1 / 1eA. (Evaluation criteria) Charpy impact strength of 1.5 kJ / m ２ For applications requiring strength, 3 kJ / m ２ The above is considered a pass.

[0054] (3) Vicat Softening Temperature According to JIS K7206 (Method B 50N), a 4 mm thick test piece prepared by compression molding was used, and the temperature at which a flat-tipped needle penetrated the test piece to a specified depth was measured at a heating rate of 50°C / h and a load of 50N. (Evaluation Criteria) A Vicat softening temperature of 70°C or higher was considered acceptable. Note that if the Vicat softening temperature is too low, deformation due to heat is likely to occur, and the test piece may not be suitable for certain industrial product applications.

[0055] (4) Transparency (Haze) In accordance with JIS K7136:2000, a 3 mm thick test piece prepared by compression molding was used, and the turbidity was measured using a turbidity meter "NDH2000 (product name)" manufactured by Nippon Denshoku Industries Co., Ltd., under the condition that light was incident on the surface on the light diffusion layer side. (Evaluation Criteria) A haze of 15% or less was considered to be acceptable.

[0056] (5) Transparency (total light transmittance) In accordance with JIS K7361-1:1997, a test piece having a thickness of 3 mm prepared by compression molding was used, and the turbidity was measured using a turbidity meter "NDH2000 (product name)" manufactured by Nippon Denshoku Industries Co., Ltd., under the condition that light was incident on the surface on the light diffusion layer side. (Evaluation criteria) A total light transmittance of 80% or more was considered to be acceptable.

[0057] (6) Heat Resistance (Metrastat) The compound was kneaded with a test roll at 180°C for 5 minutes, and a sheet was taken out. Next, a test piece measuring 30 cm in length, 2 cm in width, and 0.3 mm in thickness was cut from the sheet and placed in a heat stability tester (Metrastat) at 190°C. The progress of blackening was checked every 30 minutes, and the time at which blackening finally began was measured. (Evaluation Criteria) Heat resistance (Metrastat) of 200 minutes or more was considered to be acceptable.

[0058] (7) Heat Resistance (Labo Plastomill) The compound was placed in a Labo Plastomill mixer (Toyo Seiki Seisakusho) and kneaded at 190°C and 60 rpm. The time until complete blackening (the timing at which the torque began to increase rapidly) was measured. (Evaluation Criteria) Heat resistance (Labo Plastomill) was considered to be acceptable when it took 7 minutes or more.

[0059]

[0060]

[0061] As is clear from the evaluation results in Tables 1 and 2, the vinyl chloride resin compositions (Examples 1 to 14) containing 0.5 to 2.6 parts by mass of an organic acid zinc salt as a stabilizer and 2 to 5 parts by mass of a bisphenol A epoxy resin have superior transparency and heat resistance to the vinyl chloride resin composition (Reference Example) that uses a conventional tin-based stabilizer. On the other hand, the vinyl chloride resin composition (Comparative Example 1) containing 1.6 parts by mass of a Ca-Zn-based stabilizer as a stabilizer and 2 to 5 parts by mass of a bisphenol A epoxy resin is insufficient in both transparency and heat resistance. Furthermore, vinyl chloride resin compositions containing 0.5 to 2.6 parts by mass of an organic acid zinc salt as a stabilizer but containing less than 2 parts by mass of bisphenol A epoxy resin (Comparative Examples 2 and 5) and a vinyl chloride resin composition containing 0.5 to 2.6 parts by mass of an organic acid zinc salt as a stabilizer but containing no bisphenol A epoxy resin (Comparative Example 3) are found to have excellent transparency but insufficient heat resistance. Furthermore, a vinyl chloride resin composition containing 1.6 parts by mass of a Ca—Zn stabilizer as a stabilizer but containing no bisphenol A epoxy resin (Comparative Example 4) is found to have insufficient transparency and heat resistance.

Claims

1. A vinyl chloride resin composition (excluding those containing an organic tin stabilizer) comprising at least 100 parts by mass of vinyl chloride resin, 0.5 to 2.6 parts by mass of an organic acid zinc salt stabilizer, and 2 to 5 parts by mass of a bisphenol A type epoxy resin.

2. The vinyl chloride resin composition according to claim 1, wherein the organic acid zinc salt stabilizer is a zinc salt of at least one organic acid selected from the group consisting of zinc benzoate, zinc toluate, zinc 4-tert-butylbenzoate, zinc stearate, zinc laurate, zinc versatate, zinc octoate, zinc oleate, zinc palmitate, and zinc myristate.

3. The vinyl chloride resin composition according to claim 1, further comprising a phosphite ester compound.

4. The vinyl chloride resin composition according to claim 1, further comprising a methyl methacrylate-butadiene-styrene copolymer.

5. The vinyl chloride resin composition according to claim 1, further comprising a processing aid.

6. The vinyl chloride resin composition according to claim 1, further comprising a lubricant.

7. A molded article comprising the vinyl chloride resin composition according to any one of claims 1 to 6.

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