Vinyl chloride-based resin composition and vinyl chloride-based resin molded body

Abstract

Provided is a vinyl chloride-based resin composition capable of suppressing discoloration if an obtained vinyl chloride-based resin molded body is irradiated with light for a long period of time.　A vinyl chloride-based resin composition according to the present invention contains a vinyl chloride-based resin, a heat stabilizer, an isocyanurate compound, and a phosphite compound.

Description

Vinyl chloride resin composition and vinyl chloride resin molded article

[0001] The present invention relates to a vinyl chloride resin composition and a vinyl chloride resin molded article using the vinyl chloride resin composition.

[0002] Vinyl chloride resins are processed into various molded articles such as joints, pipes, plates, containers, etc., and are used in many fields. Vinyl chloride resins are particularly suitable for use in pipes because of their excellent mechanical strength, weather resistance, heat resistance, and chemical resistance.

[0003] However, the weather resistance of vinyl chloride resin molded articles (vinyl chloride resin pipes) obtained using conventional vinyl chloride resin compositions may decrease with use. Specifically, when conventional vinyl chloride resin molded articles are used outdoors, the vinyl chloride resin may decompose due to ultraviolet rays, ambient temperature, etc., causing discoloration of the outer surface and a decrease in design appeal.

[0004] To solve these problems, an ultraviolet absorber is sometimes added to the vinyl chloride resin composition.

[0005] Patent Document 1 below discloses an exterior cover for a cooler that is a molded article of a vinyl chloride resin composition. The vinyl chloride resin composition contains 100 parts by weight of vinyl chloride resin or chlorinated vinyl chloride resin, 0.01 to 1 part by weight of an ultraviolet absorber, 1 to 3 parts by weight of an organotin-based heat stabilizer, and 1 to 5 parts by weight of hydrotalcite represented by a specific formula.

[0006] Japanese Patent Application Publication No. 10-217358

[0007] Molded articles of vinyl chloride resin compositions such as those described in Patent Document 1 may not be able to sufficiently improve weather resistance. In particular, when molded articles of vinyl chloride resin compositions are dark colors such as black and gray, there is a problem that when molded articles of conventional vinyl chloride resin compositions are used outdoors for a long period of time (e.g., one year or more), chalking (whitening) occurs, resulting in a deterioration in design. It is believed that chalking occurs due to surface deterioration caused by light, surface deterioration caused by moisture, the effects of colorants, the effects of dispersants, and the bloom phenomenon of additives.

[0008] Furthermore, when a molded article of a vinyl chloride resin composition is light in color, discoloration may occur when a molded article of a conventional vinyl chloride resin composition is used outdoors, resulting in a deterioration in design.

[0009] That is, with conventional vinyl chloride resin compositions, it is difficult to improve the weather resistance of the resulting vinyl chloride resin molded article, and it is also difficult to suppress discoloration when the vinyl chloride resin molded article is irradiated with light for a long period of time.

[0010] An object of the present invention is to provide a vinyl chloride resin composition that can suppress discoloration of the resulting vinyl chloride resin molded article when exposed to light for a long period of time. Another object of the present invention is to provide a vinyl chloride resin molded article using the vinyl chloride resin composition.

[0011] This specification discloses the following vinyl chloride resin composition and vinyl chloride resin molded article.

[0012] Item 1. A vinyl chloride resin composition comprising a vinyl chloride resin, a heat stabilizer, an isocyanurate compound, and a phosphite compound.

[0013] Item 2. The vinyl chloride resin composition according to Item 1, wherein the amount of the isocyanurate compound is 0.01 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

[0014] Item 3. The vinyl chloride resin composition according to Item 1, wherein the content of the phosphite compound is 0.01 parts by weight or more and 2.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

[0015] Item 4. The vinyl chloride resin composition according to Item 1, wherein the amount of the isocyanurate compound is 0.01 parts by weight or more and 5.0 parts by weight or less relative to 100 parts by weight of the vinyl chloride resin, and the amount of the phosphite compound is 0.01 parts by weight or more and 2.0 parts by weight or less relative to 100 parts by weight of the vinyl chloride resin.

[0016] Item 5. The vinyl chloride resin composition according to any one of Items 1 to 4, wherein the isocyanurate compound includes an isocyanurate compound having a hydroxyl group or a carboxyl group.

[0017] Item 6. The vinyl chloride resin composition according to any one of Items 1 to 5, wherein the isocyanurate compound includes tris(2-hydroxyethyl)isocyanurate.

[0018] Item 7. The vinyl chloride resin composition according to any one of Items 1 to 6, wherein the phosphite compound includes a trialkyl phosphite.

[0019] Item 8. The vinyl chloride resin composition according to Item 7, wherein the phosphite compound includes trilauryl phosphite.

[0020] Item 9. The vinyl chloride resin composition according to any one of Items 1 to 8, wherein the heat stabilizer includes an organic acid zinc heat stabilizer.

[0021] Item 10. The vinyl chloride resin composition according to any one of Items 1 to 9, wherein the content of the heat stabilizer is 0.20 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

[0022] Item 11. The vinyl chloride resin composition according to any one of Items 1 to 10, wherein the amount of the phosphite compound is 1.0 part by weight or more and 1,000 parts by weight or less per 100 parts by weight of the isocyanurate compound.

[0023] Item 12. The vinyl chloride resin composition according to Item 11, wherein the amount of the phosphite compound is 10 parts by weight or more and 1,000 parts by weight or less per 100 parts by weight of the isocyanurate compound.

[0024] Item 13. The vinyl chloride resin composition according to any one of items 1 to 12, wherein the total content of the isocyanurate compound and the phosphite compound is 0.02 parts by weight or more and 5.0 parts by weight or less, based on 100 parts by weight of the vinyl chloride resin.

[0025] Item 14. A vinyl chloride resin molded article, which is a molded article of the vinyl chloride resin composition according to any one of Items 1 to 13.

[0026] Item 15. The vinyl chloride resin molded article according to Item 14, wherein the color difference ΔE of the vinyl chloride resin molded article before and after the following weather resistance test is 10 or less.

[0027] Weather resistance test: Using a metal weather tester, temperature 50°C, humidity 50% RH, wavelength 295 nm to 780 nm, illuminance 40 mW / cm ２ The light irradiation step of irradiating the vinyl chloride resin molded body with light under conditions of 50°C, 98% RH, and 6 hours and the high-humidity step of placing the vinyl chloride resin molded body in a dark place under conditions of 50°C, 98% RH, and 6 hours are alternately repeated. The light irradiation step and the high-humidity step are each performed 8 times, and the weather resistance test is carried out for a total of 96 hours.

[0028] The vinyl chloride resin composition according to the present invention contains a vinyl chloride resin, a heat stabilizer, an isocyanurate compound, and a phosphite compound. Because the vinyl chloride resin composition according to the present invention has the above-described configuration, discoloration of the resulting vinyl chloride resin molded article can be suppressed when the article is irradiated with light for a long period of time.

[0029] The present invention will be described in detail below.

[0030] (Vinyl chloride resin composition) The vinyl chloride resin composition according to the present invention contains a vinyl chloride resin, a heat stabilizer, an isocyanurate compound, and a phosphite compound.

[0031] When a molded article made from a vinyl chloride resin composition has a dark color such as black or gray, chalking (whitening) occurs when the molded article made from a conventional vinyl chloride resin composition is used outdoors for a long period of time (for example, one year or more), resulting in a problem of poor design. Furthermore, when a molded article made from a light-colored vinyl chloride resin composition is used outdoors, discoloration may occur, resulting in a poor design. In other words, with conventional vinyl chloride resin compositions, it is difficult to improve the weather resistance of the resulting vinyl chloride resin molded article, and it is difficult to prevent discoloration when the vinyl chloride resin molded article is irradiated with light for a long period of time.

[0032] Furthermore, vinyl chloride resin compositions generally contain a heat stabilizer containing zinc, which can lead to problems such as a decrease in the weather resistance of the resulting vinyl chloride resin molded article and a tendency for discoloration to occur.

[0033] On the other hand, since the vinyl chloride resin composition according to the present invention has the above-mentioned constitution, the weather resistance of the obtained vinyl chloride resin molded article can be improved and discoloration can be suppressed when the obtained vinyl chloride resin molded article is irradiated with light for a long period of time. In particular, since the vinyl chloride resin composition according to the present invention has the above-mentioned constitution, the weather resistance of the obtained vinyl chloride resin molded article can be improved and discoloration can be suppressed even when a heat stabilizer containing zinc is used.

[0034] The vinyl chloride resin composition according to the present invention is suitably used for obtaining a vinyl chloride resin molded article. The vinyl chloride resin composition according to the present invention can be used to obtain a vinyl chloride resin molded article.

[0035] Hereinafter, each component contained in the vinyl chloride resin composition will be described.

[0036] <Vinyl chloride resin> As the vinyl chloride resin, conventionally known vinyl chloride resins can be used. Examples of the vinyl chloride resin include (1) a homopolymer of a vinyl chloride monomer, (2) a copolymer of a vinyl chloride monomer and a monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer, and (3) a graft polymer in which vinyl chloride is graft-polymerized onto a polymer or copolymer other than vinyl chloride. The vinyl chloride resin may be used alone or in combination of two or more.

[0037] Examples of monomers having an unsaturated bond copolymerizable with the vinyl chloride monomer include α-olefin compounds such as ethylene, propylene, and butylene; vinyl ester compounds such as vinyl acetate and vinyl propionate; vinyl ether compounds such as butyl vinyl ether and cetyl vinyl ether; alkyl (meth)acrylate compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate; aryl (meth)acrylate compounds such as phenyl (meth)acrylate; aromatic vinyl compounds such as styrene and α-methylstyrene; dicarboxylic acid compounds such as maleic anhydride; halogenated vinyl compounds such as vinylidene chloride and vinylidene fluoride; and N-substituted maleimide compounds such as N-phenylmaleimide and N-cyclohexylmaleimide. The monomers having an unsaturated bond copolymerizable with the vinyl chloride monomer may be used alone or in combination of two or more.

[0038] The copolymer of the vinyl chloride monomer and the monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer may be a random copolymer, a block copolymer, or a graft copolymer.

[0039] Examples of the polymers and copolymers other than vinyl chloride include copolymers of an α-olefin compound and a vinyl ester compound, such as ethylene-vinyl acetate copolymer; copolymers of an α-olefin compound, a vinyl ester compound, and carbon monoxide, such as ethylene-vinyl acetate-carbon monoxide copolymer; copolymers of an α-olefin compound and an alkyl (meth)acrylate compound, such as ethylene-methyl methacrylate copolymer and ethylene-ethyl acrylate copolymer; and copolymers of an α-olefin compound, an alkyl (meth)acrylate compound, and carbon monoxide, such as ethylene-butyl acrylate-carbon monoxide copolymer; copolymers of two or more different α-olefin compounds, such as ethylene-propylene copolymer; copolymers of unsaturated nitrile compounds and diene compounds, such as acrylonitrile-butadiene copolymer; polyurethane; and chlorinated polyolefin compounds, such as chlorinated polyethylene and chlorinated polypropylene. The polymers and copolymers other than vinyl chloride may be used alone, or two or more may be used in combination.

[0040] The vinyl chloride resin contained in the vinyl chloride resin composition is preferably in the form of particles. The volume average particle diameter of the particulate vinyl chloride resin is preferably 0.1 μm or more and preferably 500 μm or less. When the volume average particle diameter is equal to or greater than the lower limit, the handleability can be improved. When the volume average particle diameter is equal to or less than the upper limit, the moldability of the vinyl chloride resin composition can be improved.

[0041] The volume average particle size of the vinyl chloride resin is the average particle size measured on a volume basis, and is the median diameter (D50) at 50%. The volume average particle size can be measured by a laser diffraction / scattering method or the like.

[0042] The average degree of polymerization of the vinyl chloride resin is preferably 500 or more, more preferably 600 or more, even more preferably 800 or more, and preferably 5000 or less, more preferably 3000 or less, even more preferably 2000 or less, and particularly preferably 1400 or less. When the average degree of polymerization of the vinyl chloride resin is at least the above-mentioned lower limit, the mechanical strength and impact resistance of the obtained vinyl chloride resin molded article can be increased, and long-term performance such as fatigue properties can be made less likely to be impaired. When the average degree of polymerization of the vinyl chloride resin is at most the above-mentioned upper limit, there is no need to raise the temperature during molding of the vinyl chloride resin composition, and moldability is improved.

[0043] The average degree of polymerization of the vinyl chloride resin can be measured, for example, as follows. The vinyl chloride resin is dissolved in tetrahydrofuran (THF), and then insoluble components are removed by filtration. The THF in the filtrate is dried and removed to obtain a measurement sample. The average degree of polymerization of the measurement sample measured in accordance with JIS K6721 "Testing Methods for Vinyl Chloride Resins" is taken as the average degree of polymerization of the vinyl chloride resin.

[0044] The polymerization method of the vinyl chloride monomer and the polymerization method of the vinyl chloride monomer and the monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer are not particularly limited. Examples of the polymerization method include suspension polymerization, emulsion polymerization, solution polymerization, bulk polymerization, and precipitation polymerization. From the viewpoint of efficiently obtaining a vinyl chloride resin, the polymerization method is preferably suspension polymerization, emulsion polymerization, solution polymerization, or precipitation polymerization.

[0045] The vinyl chloride resin may be a chlorinated vinyl chloride resin or a non-chlorinated vinyl chloride resin. From the viewpoint of improving heat resistance, the vinyl chloride resin is preferably a chlorinated vinyl chloride resin. The chlorinated vinyl chloride resin is a resin obtained by chlorinating a vinyl chloride resin.

[0046] The chlorinated vinyl chloride resin is preferably obtained by polymerizing the vinyl chloride monomer or the vinyl chloride monomer with a monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer to obtain a vinyl chloride resin, and then chlorinating the vinyl chloride resin.

[0047] The method for chlorinating the vinyl chloride resin is not particularly limited. Examples of the method for chlorinating the vinyl chloride resin include a method in which the vinyl chloride resin is placed in an aqueous solvent to obtain a suspension, and then chlorine is added to react the vinyl chloride resin with chlorine. This chlorination reaction proceeds under heating conditions or light irradiation conditions.

[0048] From the viewpoint of enhancing the thermal stability of the resulting chlorinated vinyl chloride resin, the chlorination reaction is preferably carried out under heating conditions.

[0049] From the viewpoint of increasing the efficiency of the chlorination reaction, the temperature during the heating is preferably 80°C or higher and preferably 140°C or lower.

[0050] The chlorine content of the vinyl chloride resin is preferably 56.8% by weight or more and preferably 72% by weight or less. The chlorine content of the vinyl chloride resin is the content of chlorine atoms in 100% by weight of the vinyl chloride resin. When the chlorine content of the vinyl chloride resin is equal to or more than the lower limit, the heat resistance of the obtained vinyl chloride resin molded article can be further improved. When the chlorine content of the vinyl chloride resin is equal to or less than the upper limit, the moldability of the vinyl chloride resin composition can be improved, and the impact resistance and surface smoothness of the obtained vinyl chloride resin molded article can be improved.

[0051] When the vinyl chloride resin is a chlorinated vinyl chloride resin, the chlorine content of the chlorinated vinyl chloride resin is preferably 56.8% by weight or more, more preferably 60% by weight or more, even more preferably 61.5% by weight or more, and preferably 72% by weight or less, more preferably 67.5% by weight or less. When the chlorine content of the chlorinated vinyl chloride resin is equal to or greater than the above lower limit, the heat resistance of the obtained vinyl chloride resin molded article can be further improved. When the chlorine content of the chlorinated vinyl chloride resin is equal to or less than the above upper limit, the moldability of the vinyl chloride resin composition can be improved, and the impact resistance and surface smoothness of the obtained vinyl chloride resin molded article can be improved.

[0052] The chlorine content of the vinyl chloride resin (when the vinyl chloride resin is a chlorinated vinyl chloride resin, the chlorine content of the chlorinated vinyl chloride resin) can be determined by potentiometric titration in accordance with JIS K7229.

[0053] The content of the vinyl chloride resin in 100% by weight of the vinyl chloride resin composition is preferably 10% by weight or more, more preferably 20% by weight or more, even more preferably 25% by weight or more, and is preferably 99.9% by weight or less, more preferably 99% by weight or less, even more preferably 97% by weight or less. When the content of the vinyl chloride resin is equal to or greater than the lower limit, the mechanical strength and impact resistance of the resulting vinyl chloride resin molded article can be increased. When the content of the vinyl chloride resin is equal to or less than the upper limit, high temperatures are not required during molding of the vinyl chloride resin composition, resulting in good moldability.

[0054] <Heat stabilizer> The vinyl chloride resin composition according to the present invention contains the heat stabilizer, which can capture hydrogen chloride generated during decomposition of the vinyl chloride resin, thereby suppressing resin deterioration due to hydrogen chloride, improving the thermal stability of the vinyl chloride resin composition during molding, and enhancing the weather resistance and suppressing discoloration of the resulting vinyl chloride resin molded article.

[0055] Examples of the heat stabilizer include a tin-based heat stabilizer, a lead-based heat stabilizer, and an organic acid metal salt-based heat stabilizer. From the viewpoint of further improving the thermal stability of the vinyl chloride resin composition during molding, the heat stabilizer is preferably a tin-based heat stabilizer, a lead-based heat stabilizer, or an organic acid metal salt-based heat stabilizer. The heat stabilizers may be used alone or in combination of two or more.

[0056] Examples of the tin-based heat stabilizer include organic tin-based heat stabilizers. Examples of the organic tin-based heat stabilizers include tin mercapto-based heat stabilizers, tin malate-based heat stabilizers, and tin carboxylate-based heat stabilizers. Examples of the tin mercapto-based heat stabilizers include monoalkyltin mercapto, dialkyltin mercapto, monoalkyltin mercapto polymer, dialkyltin mercapto polymer, monoalkyltin mercapto sulfide, and dialkyltin mercapto sulfide. Examples of the tin malate-based heat stabilizers include monoalkyltin maleates, dialkyltin maleates, monoalkyltin maleate polymers, and dialkyltin maleate polymers. Examples of the tin carboxylate-based heat stabilizers include monoalkyltin carboxylates and dialkyltin carboxylates. The tin-based heat stabilizers may be used alone or in combination of two or more.

[0057] Examples of the lead-based heat stabilizer include tribasic lead sulfate, tetrabasic lead sulfate, basic lead sulfite, dibasic lead phosphite, dibasic lead phthalate, tribasic lead maleate, dibasic lead stearate, and basic lead sulfite phosphite.

[0058] Examples of the organic acid metal salt-based heat stabilizer include calcium-zinc-based heat stabilizers, barium-zinc-based heat stabilizers, barium-cadmium-based heat stabilizers, calcium stearate, zinc stearate, barium stearate, etc. The material constituting the organic acid metal salt-based heat stabilizer is not particularly limited, and examples thereof include stearic acid, lauric acid, and ricinoleic acid.

[0059] From the viewpoint of improving heat resistance, the heat stabilizer preferably contains an organic acid metal salt-based heat stabilizer. From the viewpoint of suppressing the occurrence of discoloration, the organic acid metal salt-based heat stabilizer more preferably contains zinc. From the viewpoint of suppressing the occurrence of discoloration, the heat stabilizer more preferably contains an organic acid zinc-based heat stabilizer. However, depending on the type of zinc-containing heat stabilizer, although discoloration can be suppressed, there is a possibility that zinc discoloration may occur to some extent. From the viewpoint of suppressing zinc discoloration, the heat stabilizer preferably contains a calcium-zinc-based heat stabilizer.

[0060] From the viewpoint of reducing the toxicity of the vinyl chloride resin composition, it is preferable that the heat stabilizer does not contain the lead-based heat stabilizer.

[0061] The content of the heat stabilizer in 100% by weight of the vinyl chloride resin composition is preferably 0.2% by weight or more, more preferably 0.5% by weight or more, even more preferably 0.8% by weight or more, particularly preferably 1.0% by weight or more, and is preferably 5.0% by weight or less, more preferably 2.5% by weight or less, even more preferably 2.2% by weight or less, particularly preferably 2.0% by weight or less. When the content of the heat stabilizer is at least the above lower limit, the heat resistance of the resulting vinyl chloride resin molded article can be further improved, and the generation of bubbles in the resulting vinyl chloride resin molded article can be effectively suppressed. When the content of the heat stabilizer is at most the above upper limit, the heat resistance of the resulting vinyl chloride resin molded article can be further improved.

[0062] The content of the heat stabilizer relative to 100 parts by weight of the vinyl chloride resin is preferably 0.20 parts by weight or more, more preferably 0.25 parts by weight or more, even more preferably 0.30 parts by weight or more, and preferably 5.0 parts by weight or less, more preferably 4.5 parts by weight or less, and even more preferably 4.0 parts by weight or less. When the content of the heat stabilizer is equal to or greater than the lower limit, the heat resistance of the resulting vinyl chloride resin molded article can be further improved, and the generation of bubbles in the resulting vinyl chloride resin molded article can be effectively suppressed. When the content of the heat stabilizer is equal to or less than the upper limit, the heat resistance of the resulting vinyl chloride resin molded article can be further improved.

[0063] <Isocyanurate Compound> The isocyanurate compound has an isocyanurate structure. The isocyanurate structure is a structure containing an isocyanurate ring formed in association with a trimerization reaction of an isocyanate group in an isocyanate compound. That is, the isocyanurate compound contains an isocyanurate ring.

[0064] The vinyl chloride resin composition according to the present invention contains the above-mentioned isocyanurate compound, which can suppress resin deterioration by capturing hydrogen chloride generated during decomposition of the vinyl chloride resin, improve the thermal stability of the vinyl chloride resin composition during molding, and enhance the weather resistance and suppress discoloration of the resulting vinyl chloride resin molded article.

[0065] From the viewpoint of more effectively exerting the effects of the present invention, the isocyanurate compound preferably contains an isocyanurate compound having a hydroxyl group or a carboxyl group. From the viewpoint of more effectively exerting the effects of the present invention, the isocyanurate compound preferably contains an isocyanurate compound having a hydroxyl group or an isocyanurate compound having a carboxyl group, and more preferably contains an isocyanurate compound having a hydroxyl group.

[0066] In order to more effectively exert the effects of the present invention, the isocyanurate compound preferably has a structure represented by the following formula (1):

[0067]

[0068] In the above formula (1), R1, R2, and R3 each represent a group containing a hydroxyl group or a group containing a carboxyl group.

[0069] Examples of the hydroxyl group-containing group include a hydroxyl group, a hydroxymethyl group, and a hydroxyethyl group. Examples of the carboxyl group-containing group include a carboxyl group, a carboxymethyl group, and a carboxyethyl group. In the formula (1), R1, R2, and R3 may be the same or different.

[0070] In order to more effectively exert the effects of the present invention, it is preferable that R1, R2, and R3 in the above formula (1) each represent a hydroxymethyl group, a hydroxyethyl group, a carboxymethyl group, or a carboxyethyl group.

[0071] Examples of the isocyanurate compound include tris(hydroxymethyl)isocyanurate, tris(2-hydroxyethyl)isocyanurate, and tris(carboxyethyl)isocyanurate. The isocyanurate compounds may be used alone or in combination of two or more.

[0072] From the viewpoint of more effectively exerting the effects of the present invention, it is particularly preferable that the isocyanurate compound contains tris(2-hydroxyethyl)isocyanurate.

[0073] The content of the isocyanurate compound in 100% by weight of the vinyl chloride resin composition is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, even more preferably 0.10% by weight or more, even more preferably 0.12% by weight or more, particularly preferably 0.14% by weight or more, and most preferably 0.16% by weight or more, and is preferably 5.0% by weight or less, more preferably 4.0% by weight or less, even more preferably 3.5% by weight or less, even more preferably 3.0% by weight or less, particularly preferably 2.5% by weight or less, and most preferably 2.0% by weight or less. The content of the isocyanurate compound in 100% by weight of the vinyl chloride resin composition may be 0.2% by weight or more, 0.3% by weight or more, 1.5% by weight or less, 1.0% by weight or less, or 0.5% by weight or less. When the content of the isocyanurate compound is equal to or greater than the lower limit, thermal stability can be improved. When the content of the isocyanurate compound is equal to or less than the upper limit, discoloration can be suppressed.

[0074] The content of the isocyanurate compound relative to 100 parts by weight of the vinyl chloride resin is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, even more preferably 0.10 parts by weight or more, particularly preferably 0.12 parts by weight or more, and most preferably 0.14 parts by weight or more, and is preferably 5.0 parts by weight or less, more preferably 4.0 parts by weight or less, even more preferably 3.5 parts by weight or less, even more preferably 3.0 parts by weight or less, particularly preferably 2.5 parts by weight or less, and most preferably 2.0 parts by weight or less. The content of the isocyanurate compound relative to 100 parts by weight of the vinyl chloride resin may be 1.0 part by weight or less. When the content of the isocyanurate compound is equal to or greater than the lower limit, thermal stability can be improved. When the content of the isocyanurate compound is equal to or less than the upper limit, discoloration can be suppressed.

[0075] <Phosphite Compound> The vinyl chloride resin composition contains a phosphite compound. When the vinyl chloride resin composition according to the present invention contains the phosphite compound, it can capture hydrogen chloride generated during decomposition of the vinyl chloride resin, thereby suppressing the generation of bubbles due to hydrogen chloride, improving the thermal stability of the vinyl chloride resin composition during molding, and increasing the weather resistance and suppressing discoloration of the resulting vinyl chloride resin molded article. The phosphite compounds may be used alone or in combination of two or more.

[0076] In order to more effectively exert the effects of the present invention, the phosphite compound is preferably an organic phosphite compound.

[0077] From the viewpoint of more effectively exerting the effects of the present invention, the molecular weight of the phosphite compound is preferably 300 or more, more preferably 400 or more, and even more preferably 500 or more, and is preferably 1,000 or less, more preferably 900 or less, and even more preferably 800 or less.

[0078] Examples of the phosphite compound include trialkyl phosphites, alkylaryl phosphites, triaryl phosphites, and oligophosphites. The phosphite compounds may be used alone or in combination of two or more.

[0079] Examples of trialkyl phosphites include tributyl phosphite, triethyl phosphite, tridecyl phosphite, and trilauryl phosphite.

[0080] Examples of the alkylaryl phosphites include mono-iso-octyldiphenyl phosphite, monotridecyldiphenyl phosphite, and di-iso-decylmonophenyl phosphite.

[0081] Examples of triaryl phosphites include triphenyl phosphite, tris(p-phenylphenyl) phosphite, and tris(p-nonylphenyl) phosphite.

[0082] Examples of oligophosphites include tetraphenyldipropylene diphosphite, distearyl pentaerythritol diphosphite, and dinonylphenyl pentaerythritol diphosphite.

[0083] From the viewpoint of more effectively exerting the effects of the present invention, the phosphite compound preferably contains a trialkyl phosphite or an oligophosphite, and more preferably contains a trialkyl phosphite.

[0084] From the viewpoint of improving weather resistance, the number of carbon atoms in the alkyl group in the trialkyl phosphite is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more, and is preferably 18 or less, more preferably 16 or less, and even more preferably 14 or less.

[0085] In order to more effectively exert the effects of the present invention, the phosphite compound preferably contains trilauryl phosphite.

[0086] The content of the phosphite compound in 100% by weight of the vinyl chloride resin composition is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, even more preferably 0.10% by weight or more, even more preferably 0.15% by weight or more, particularly preferably 0.2% by weight or more, and most preferably 0.3% by weight or more, and is preferably 5.0% by weight or less, more preferably 2.0% by weight or less, even more preferably 1.9% by weight or less, even more preferably 1.7% by weight or less, particularly preferably 1.5% by weight or less, and most preferably 1.0% by weight or less. The content of the phosphite compound in 100% by weight of the vinyl chloride resin composition may be 0.3% by weight or more, or may be 0.5% by weight or less. When the content of the phosphite compound is equal to or greater than the lower limit, weather resistance can be further improved. When the content of the phosphite compound is equal to or less than the upper limit, bleeding can be suppressed.

[0087] The content of the phosphite compound is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, even more preferably 0.1 parts by weight or more, and particularly preferably 0.5 parts by weight or more, relative to 100 parts by weight of the vinyl chloride resin; it is preferably 5.0 parts by weight or less, more preferably 4.0 parts by weight or less, even more preferably 3.0 parts by weight or less, even more preferably 2.0 parts by weight or less, even more preferably 1.9 parts by weight or less, particularly preferably 1.7 parts by weight or less, especially more preferably 1.5 parts by weight or less, and most preferably 1.0 part by weight or less. When the content of the phosphite compound is equal to or greater than the lower limit, weather resistance can be further improved. When the content of the phosphite compound is equal to or less than the upper limit, bleeding can be suppressed.

[0088] The content of the phosphite compound is preferably 1.0 part by weight or more, more preferably 10 parts by weight or more, even more preferably 50 parts by weight or more, particularly preferably 100 parts by weight or more, and is preferably 1000 parts by weight or less, more preferably 900 parts by weight or less, and even more preferably 800 parts by weight or less, relative to 100 parts by weight of the isocyanurate compound. When the content of the phosphite compound is equal to or greater than the lower limit, weather resistance can be further improved. When the content of the phosphite compound is equal to or less than the upper limit, bleeding can be suppressed ... 20 parts by weight, relative to 100 parts by weight of the isocyanurate compound, the content of the phosphite compound may be 20 parts by weight or less, or may be 200 parts by weight or more.

[0089] The content of the phosphite compound preferably satisfies at least one of the ranges of 1.0 part by weight to 20 parts by weight and the range of 100 parts by weight to 1,000 parts by weight per 100 parts by weight of the isocyanurate compound. Even when such a range is adopted, the thermal stability during molding of the vinyl chloride resin composition can be effectively improved, the weather resistance of the obtained vinyl chloride resin molded article can be effectively enhanced, and discoloration can be effectively suppressed.

[0090] The content of the phosphite compound, relative to 100 parts by weight of the isocyanurate compound, preferably satisfies at least one of the ranges of 1.0 part by weight to 20 parts by weight and the range of 200 parts by weight to 1000 parts by weight. Even when such a range is adopted, the thermal stability of the vinyl chloride resin composition during molding can be effectively improved, the weather resistance of the resulting vinyl chloride resin molded article can be effectively enhanced, and discoloration can be effectively suppressed.

[0091] In 100% by weight of the vinyl chloride resin composition, the total content of the isocyanurate compound and the phosphite compound is preferably 0.02% by weight or more, more preferably 0.05% by weight or more, even more preferably 0.1% by weight or more, even more preferably 0.3% by weight or more, even more preferably 0.5% by weight or more, particularly preferably 0.6% by weight or more, and is preferably 10% by weight or less, more preferably 8.0% by weight or less, and even more preferably 6.0% by weight or less. When the total content of the isocyanurate compound and the phosphite compound is equal to or greater than the lower limit, weather resistance can be further improved. When the total content of the isocyanurate compound and the phosphite compound is equal to or less than the upper limit, discoloration can be suppressed.

[0092] The total content of the isocyanurate compound and the phosphite compound is preferably 0.3% by weight or more and 10% by weight or less, based on 100% by weight of the vinyl chloride resin composition, which further improves the thermal stability of the vinyl chloride resin composition during molding, further enhances the weather resistance of the resulting vinyl chloride resin molded article, and further suppresses discoloration.

[0093] The total content of the isocyanurate compound and the phosphite compound is preferably 0.6% by weight or more and 10% by weight or less, based on 100% by weight of the vinyl chloride resin composition, which further improves the thermal stability of the vinyl chloride resin composition during molding, further enhances the weather resistance of the resulting vinyl chloride resin molded article, and further suppresses discoloration.

[0094] The total content of the isocyanurate compound and the phosphite compound relative to 100 parts by weight of the vinyl chloride resin is preferably 0.01 parts by weight or more, more preferably 0.02 parts by weight or more, even more preferably 0.03 parts by weight or more, even more preferably 0.2 parts by weight or more, even more preferably 0.4 parts by weight or more, even more preferably 0.5 parts by weight or more, particularly preferably 0.7 parts by weight or more, and is preferably 5.0 parts by weight or less, more preferably 4.0 parts by weight or less, and even more preferably 3.0 parts by weight or less. When the total content of the isocyanurate compound and the phosphite compound is equal to or greater than the lower limit, weather resistance can be further improved. When the total content of the isocyanurate compound and the phosphite compound is equal to or less than the upper limit, discoloration can be suppressed.

[0095] The total content of the isocyanurate compound and the phosphite compound is preferably 0.4 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin, which further improves the thermal stability of the vinyl chloride resin composition during molding, further enhances the weather resistance of the resulting vinyl chloride resin molded article, and further suppresses discoloration.

[0096] The total content of the isocyanurate compound and the phosphite compound is preferably 0.7 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin, which further improves the thermal stability of the vinyl chloride resin composition during molding, further enhances the weather resistance of the resulting vinyl chloride resin molded article, and further suppresses discoloration.

[0097] <Other Components> The vinyl chloride resin composition may contain additives as needed. Examples of the additives include heat stabilization aids, antioxidants, lubricants, processing aids, impact modifiers, heat resistance improvers, UV absorbers, antistatic agents, light stabilizers, fillers, colorants, and plasticizers. The additives may be used alone or in combination of two or more.

[0098] Examples of the heat stabilization aid include epoxidized soybean oil, phosphate ester, polyol, hydrotalcite, zeolite, etc. The heat stabilization aid may be used alone or in combination of two or more.

[0099] Examples of the antioxidant include phenol-based antioxidants, amine-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, etc. The antioxidants may be used alone or in combination of two or more.

[0100] Examples of the lubricant include internal lubricants and external lubricants. The internal lubricant is used to reduce the flow viscosity of the molten resin during molding and prevent frictional heat generation. Examples of the internal lubricant include butyl stearate, lauryl alcohol, stearyl alcohol, epoxidized soybean oil, glycerin monostearate, stearic acid, and bisamide. The external lubricant is used to improve the sliding effect between the molten resin and the metal surface during molding. Examples of the external lubricant include paraffin wax, polyolefin wax, ester wax, and montanic acid wax. Only one type of the lubricant may be used, or two or more types may be used in combination.

[0101] Examples of the processing aid include acrylic processing aids. Examples of the acrylic processing aid include 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. Only one type of the processing aids may be used, or two or more types may be used in combination.

[0102] Examples of the impact modifier include methyl methacrylate-butadiene-styrene copolymer (MBS), chlorinated polyethylene, acrylic rubber, etc. The impact modifier may be used alone or in combination of two or more.

[0103] Examples of the heat resistance improver include α-methylstyrene-based and N-phenylmaleimide-based resins, etc. The heat resistance improver may be used alone or in combination of two or more.

[0104] Examples of the ultraviolet absorber include salicylic acid ester-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers. The ultraviolet absorbers may be used alone or in combination of two or more.

[0105] Examples of the light stabilizer include hindered amine light stabilizers, etc. The light stabilizers may be used alone or in combination of two or more.

[0106] Examples of the filler include calcium carbonate, talc, etc. The filler may be used alone or in combination of two or more.

[0107] Examples of the colorant include pigments and dyes. The colorant preferably contains a pigment. Examples of the pigment include organic pigments and inorganic pigments. Examples of the organic pigment include azo-based organic pigments, phthalocyanine-based organic pigments, threne-based organic pigments, and dye lake-based organic pigments. Examples of the inorganic pigment include oxide-based inorganic pigments, molybdenum chromate-based inorganic pigments, sulfide / selenide-based inorganic pigments, and ferrocyanide-based inorganic pigments. Only one type of the colorant may be used, or two or more types may be used in combination.

[0108] From the viewpoint of improving the design properties of the obtained vinyl chloride resin molded article, the vinyl chloride resin composition preferably contains a colorant, which may be a black colorant, a red colorant, a blue colorant, a yellow colorant, or a white colorant.

[0109] The content of the colorant is not particularly limited. The content of the colorant in 100% by weight of the vinyl chloride resin composition is preferably 0.02% by weight or more, more preferably 0.05% by weight or more, even more preferably 0.1% by weight or more, and is preferably 10% by weight or less, more preferably 8.0% by weight or less, even more preferably 6.0% by weight or less, and particularly preferably 4.0% by weight or less. When the content of the colorant is equal to or more than the lower limit and equal to or less than the upper limit, it is easy to appropriately color the vinyl chloride resin molded article.

[0110] The plasticizer may be added to improve processability during molding. Since the addition of a plasticizer may reduce the heat resistance of the molded product, it is preferable to add a small amount of plasticizer. Examples of the plasticizer include dibutyl phthalate, di-2-ethylhexyl phthalate, and di-2-ethylhexyl adipate. Only one type of the plasticizer may be used, or two or more types may be used in combination.

[0111] (Vinyl chloride resin molded article) The vinyl chloride resin molded article according to the present invention is a molded article of the vinyl chloride resin composition described above. The vinyl chloride resin molded article is formed using the vinyl chloride resin composition. The vinyl chloride resin molded article is obtained by molding the vinyl chloride resin composition.

[0112] The vinyl chloride resin molded article according to the present invention has the above-mentioned configuration, and therefore can improve heat resistance, prevent appearance defects, and improve impact resistance.

[0113] Examples of the shape of the vinyl chloride resin molded article include a pipe, a plate, and a container. The vinyl chloride resin molded article is preferably in the form of a pipe (tube). The vinyl chloride resin molded article is preferably a vinyl chloride resin pipe, and is preferably used as a vinyl chloride resin pipe (use of the vinyl chloride resin composition to obtain a vinyl chloride resin pipe). The vinyl chloride resin molded article is preferably a rain gutter, and is also preferably used as a rain gutter (use of the vinyl chloride resin composition to obtain a rain gutter).

[0114] Using a metal weather tester, the temperature was 50°C, humidity was 50% RH, wavelength was 295 nm to 780 nm, and illuminance was 40 mW / cm. ２ The weather resistance test is carried out by alternately repeating a light irradiation step in which the vinyl chloride resin molded body is irradiated with light under conditions of a temperature of 50°C, a humidity of 98% RH, and 6 hours, and a high-humidity step in which the vinyl chloride resin molded body is placed in a dark place under conditions of a temperature of 50°C, a humidity of 98% RH, and 6 hours. The light irradiation step and the high-humidity step are each carried out 8 times, and the weather resistance test is carried out for a total of 96 hours (the above is the weather resistance test). The number of repetitions is 8 ((6 hours + 6 hours) x 8 = 96 hours). The color difference ΔE of the vinyl chloride resin molded body before and after the weather resistance test is preferably 20 or less. The color difference ΔE of the vinyl chloride resin molded body before and after the weather resistance test is more preferably 15 or less, even more preferably 12 or less, particularly preferably 10 or less, even more preferably 8.0 or less, particularly preferably 6.0 or less, and most preferably 5.0 or less. When the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test is not more than the above upper limit, discoloration of the vinyl chloride resin molded article can be more effectively suppressed, and the occurrence of poor appearance can be more effectively prevented. There is no particular limitation on the lower limit of the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test. The color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test may be 0 or more, 0.1 or more, 0.5 or more, or 1.0 or more. The range of the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test can be set by appropriately selecting the above lower limit and upper limit.

[0115] When the lightness L value of the vinyl chloride resin molded article is 60 or more, the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test is preferably 12 or less, more preferably 10 or less, even more preferably 8.0 or less, particularly preferably 6.0 or less, and most preferably 5.0 or less. When the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test is not more than the above upper limit, discoloration of the vinyl chloride resin molded article can be more effectively suppressed, and the occurrence of poor appearance can be more effectively prevented. When the lightness L value of the vinyl chloride resin molded article is 60 or more, there is no particular limitation on the lower limit of the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test. When the lightness L value of the vinyl chloride resin molded article is 60 or more, the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test may be 0 or more, 0.1 or more, 0.5 or more, or 1.0 or more. The color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test may be 8.0 or less, 6.0 or less, or 5.0 or less. The range of the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test can be set by appropriately selecting the lower limit and the upper limit.

[0116] When the lightness L value of the vinyl chloride resin molded article is less than 40 (preferably less than 30), the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test is preferably 20 or less, more preferably 15 or less, even more preferably 12 or less, and particularly preferably 10 or less. When the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test is not more than the above upper limit, discoloration of the vinyl chloride resin molded article can be more effectively suppressed, and the occurrence of poor appearance can be more effectively prevented. When the lightness L value of the vinyl chloride resin molded article is less than 40, there is no particular limitation on the lower limit of the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test. When the lightness L value of the vinyl chloride resin molded article is less than 40, the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test may be 0 or more, 0.1 or more, 0.5 or more, or 1.0 or more. The color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test may be 8.0 or less, 6.0 or less, or 5.0 or less. The range of the color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test can be set by appropriately selecting the lower limit and the upper limit.

[0117] The color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test can be measured, for example, as follows. The vinyl chloride resin molded article is placed in a metal weather (e.g., "METALWEATHER" manufactured by Daipla Wintes). Next, the weather resistance test is performed by alternately repeating the light irradiation step and the high humidity step. Thereafter, using a color difference meter (e.g., "Spectrophotometer" manufactured by Konica Minolta), the L, a, and b values ​​of the vinyl chloride resin molded article before and after the weather resistance test are measured in accordance with JIS Z8722 condition a. The color difference ΔE of the vinyl chloride resin molded article before and after the weather resistance test is calculated using the following formula from the L, a, and b values ​​of the vinyl chloride resin molded article before the weather resistance test and the L, a, and b values ​​of the vinyl chloride resin molded article after the weather resistance test.

[0118] ΔE = [(ΔL) ２ + (Δa) ２ +(Δb) ２ ] １／２

[0119] In the weather resistance test, a shower step may be performed before and after the high humidity step. In the weather resistance test, water may be sprayed onto the vinyl chloride resin molded article before and after the high humidity step.

[0120] The method for molding the vinyl chloride resin composition is not particularly limited, and examples of the method for molding the vinyl chloride resin composition include extrusion molding, injection molding, calendar molding, blow molding, and press molding.

[0121] Examples of molding machines used for molding include single-screw extruders, twin-screw counter-rotating parallel extruders, twin-screw counter-rotating conical extruders, and twin-screw co-rotating extruders. The heating temperature when molding using the above molding machines is preferably 80°C or higher and preferably 140°C or lower.

[0122] From the viewpoints of improving the heat resistance of the vinyl chloride resin molded article, preventing the occurrence of defective appearance, and improving impact resistance, the vinyl chloride resin molded article is preferably a vinyl chloride resin extrusion molded article of the vinyl chloride resin composition described above.

[0123] The vinyl chloride resin molded article according to the present invention is preferably a vinyl chloride resin pipe. The vinyl chloride resin molded article according to the present invention is suitably used as a vinyl chloride resin pipe. Furthermore, the vinyl chloride resin molded article according to the present invention is suitably used as a vinyl chloride resin pipe.

[0124] From the viewpoint of further increasing the mechanical strength and impact resistance of the vinyl chloride resin pipe, the vinyl chloride resin pipe is preferably a rigid vinyl chloride resin pipe. From the viewpoint of further increasing the mechanical strength and impact resistance of the vinyl chloride resin pipe, the molded product of the vinyl chloride resin composition (vinyl chloride resin molded product) is preferably a rigid vinyl chloride resin molded product. From the viewpoint of further increasing the mechanical strength and impact resistance of the vinyl chloride resin pipe, the vinyl chloride resin pipe preferably includes a rigid vinyl chloride resin molded product.

[0125] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0126] The following materials were prepared:

[0127] Vinyl chloride resin: "TS1000R" manufactured by Tokuyama Sekisui Kogyo Co., Ltd. (vinyl chloride resin, average degree of polymerization: 1000)

[0128] Heat stabilizer: calcium-zinc based heat stabilizer ("MDZ-CP102" manufactured by San Ace Co., Ltd.) Tin based heat stabilizer ("KK6528" manufactured by Nitto Kasei Co., Ltd.)

[0129] Isocyanurate compound: Tris(2-hydroxyethyl) isocyanurate ("THEIC" manufactured by Shikoku Kasei Holdings Co., Ltd.)

[0130] Phosphite compounds: Trilauryl phosphite ("JP-312L" manufactured by Johoku Chemical Industry Co., Ltd.) Oligophosphite ("ADEKA STAB 1500" manufactured by ADEKA Corporation)

[0131] Other ingredients: Lubricant (ester wax, "Rikemal EW-250" manufactured by Riken Vitamin Co., Ltd.) Lubricant (polyethylene wax, "Hiwax 4202E" manufactured by Mitsui Chemicals, Inc.) Antioxidant (hindered phenol antioxidant, "Irganox 1076" manufactured by BASF) Colorant (black pigment, carbon black) Colorant (white pigment) (in this specification, a white pigment that colors the product white is classified as a colorant)

[0132] Examples 1 to 5 Preparation of vinyl chloride resin compositions: The materials shown in Table 1 were blended in the amounts shown in Table 1 and mixed by stirring for 5 minutes using a Henschel mixer (Kawada Kogyosho Co., Ltd.) to obtain vinyl chloride resin compositions (vinyl chloride resin compositions containing a colorant). In addition, a vinyl chloride resin composition for evaluation of thermal stability (vinyl chloride resin composition not containing a colorant) was obtained in the same manner, except that no colorant was blended.

[0133] Preparation of vinyl chloride resin molded article: The obtained vinyl chloride resin composition (vinyl chloride resin composition containing a colorant) was kneaded and molded under the following conditions to obtain a sheet (vinyl chloride resin molded article containing a colorant) having a thickness of 3.0 mm. In addition, a vinyl chloride resin molded article (vinyl chloride resin molded article not containing a colorant) for evaluation of thermal stability was obtained in the same manner, except that a vinyl chloride resin composition for evaluation of thermal stability (vinyl chloride resin composition not containing a colorant) was used.

[0134] [Mixing conditions] Mixing roll: manufactured by Yasuda Seiki Seisakusho Roll temperature: 200°C Roll time: 1 minute (after wrapping)

[0135] [Molding conditions] Press: manufactured by Kodaira Manufacturing Co., Ltd. Press temperature: 200°C Pressing time: 3 minutes Cooling time: 3 minutes

[0136] Comparative Examples 1 to 6 Vinyl chloride resin compositions (including vinyl chloride resin compositions for evaluation of thermal stability) and vinyl chloride resin molded articles (including vinyl chloride resin molded articles for evaluation of thermal stability) were obtained in the same manner as in Example 1, except that the formulations of the vinyl chloride resin compositions were changed as shown in Table 2.

[0137] (Evaluation) (1) Discoloration Inhibition A vinyl chloride resin molded body (sheet) containing a colorant was placed in a metal weatherer ("METALWEATHER" manufactured by Daipla Wintes). Next, the metal weatherer was operated under the following conditions, and a weather resistance test was performed by repeating 8 cycles (total of 96 hours) of an ultraviolet irradiation step (L) and a high humidity step (D). Using a color difference meter ("Spectrophotometer" manufactured by Konica Minolta), the L, a, and b values ​​of the vinyl chloride resin molded body before and after the weather resistance test were measured in accordance with JIS Z8722 condition a. The color difference ΔE of the vinyl chloride resin molded body before and after the weather resistance test was calculated using the following formula from the L, a, and b values ​​of the vinyl chloride resin molded body before the weather resistance test and the L, a, and b values ​​of the vinyl chloride resin molded body after the weather resistance test. Discoloration inhibition (weather resistance) was evaluated according to the following criteria.

[0138] ΔE = [(ΔL) ２ + (Δa) ２ +(Δb) ２ ] １／２

[0139] Operation mode: L+D L: wavelength 365 nm, illuminance 40 mW / cm ２ , black panel temperature 50°C, humidity 50% RH, 6 hours D: No irradiation (dark place), black panel temperature 50°C, humidity 98% RH, 6 hours

[0140] [Evaluation criteria for discoloration prevention] ○○○: ΔE is 5.0 or less ○○: ΔE is more than 5.0 and 6.0 or less ○: ΔE is more than 6.0 and 10.0 or less ×: ΔE is more than 10.0

[0141] (2) Thermal Stability Using a vinyl chloride resin molding (sheet) containing no colorant, the thermal stability was evaluated as follows.

[0142] The obtained sheet was cut into pieces measuring 3 mm x 3 mm. The cut sheets were then placed in a gear oven at 195°C. The degree of coloring of the sheet placed in the gear oven was visually checked every 10 minutes, and the sheet was removed when it had turned brown.

[0143] [Criteria for thermal stability] ○○: Time required for browning is 80 minutes or more ○: Time required for browning is 60 to 70 minutes △: Time required for browning is 30 to 50 minutes ×: Time required for browning is 20 minutes or less

[0144] The compositions of the vinyl chloride resin compositions and the results are shown in Tables 1 to 4.

[0145]

[0146]

[0147]

[0148]

Claims

1. A vinyl chloride resin composition comprising a vinyl chloride resin, a heat stabilizer, an isocyanurate compound, and a phosphite compound.

2. The vinyl chloride resin composition according to claim 1, wherein the content of said isocyanurate compound is 0.01 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of said vinyl chloride resin.

3. The vinyl chloride resin composition according to claim 1, wherein the content of said phosphite compound is 0.01 parts by weight or more and 2.0 parts by weight or less per 100 parts by weight of said vinyl chloride resin.

4. The vinyl chloride resin composition according to claim 1, wherein the content of the isocyanurate compound is 0.01 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin, and the content of the phosphite compound is 0.01 parts by weight or more and 2.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

5. The vinyl chloride resin composition according to any one of claims 1 to 4, wherein the isocyanurate compound includes an isocyanurate compound having a hydroxyl group or a carboxyl group.

6. The vinyl chloride resin composition according to any one of claims 1 to 5, wherein the isocyanurate compound comprises tris(2-hydroxyethyl) isocyanurate.

7. The vinyl chloride resin composition according to any one of claims 1 to 6, wherein the phosphite compound comprises a trialkyl phosphite.

8. The vinyl chloride resin composition according to claim 7, wherein the phosphite compound comprises trilauryl phosphite.

9. The vinyl chloride resin composition according to any one of claims 1 to 8, wherein the heat stabilizer comprises an organic acid zinc heat stabilizer.

10. The vinyl chloride resin composition according to any one of claims 1 to 9, wherein the content of the heat stabilizer is 0.20 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

11. The vinyl chloride resin composition according to any one of claims 1 to 10, wherein the content of the phosphite compound is 1.0 part by weight or more and 1,000 parts by weight or less per 100 parts by weight of the isocyanurate compound.

12. The vinyl chloride resin composition according to claim 11, wherein the content of the phosphite compound is 10 parts by weight or more and 1,000 parts by weight or less per 100 parts by weight of the isocyanurate compound.

13. The vinyl chloride resin composition according to any one of claims 1 to 12, wherein the total content of the isocyanurate compound and the phosphite compound is 0.02 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

14. A vinyl chloride resin molded article, which is a molded article of the vinyl chloride resin composition according to any one of claims 1 to 13.

15. The vinyl chloride resin molded article according to claim 14, wherein the color difference ΔE of the vinyl chloride resin molded article before and after the following weather resistance test is 10 or less. Weather resistance test: Using a metal weather tester, temperature 50°C, humidity 50% RH, wavelength 295 nm to 780 nm, illuminance 40 mW / cm ２ A light irradiation step in which the vinyl chloride resin molded body is irradiated with light under conditions of 50°C, 98% RH, and 6 hours, and a high-humidity step in which the vinyl chloride resin molded body is placed in a dark place under conditions of 50°C, 98% RH, and 6 hours, are alternately repeated. The light irradiation step and the high humidity step are each carried out eight times, and the weather resistance test is carried out for a total of 96 hours.

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