Vinyl chloride resin composition and vinyl chloride resin molded article

Abstract

To provide a vinyl chloride resin composition that achieves improved thermal stability in heat molding and allows suppression of plate-out during continuous production of molded articles over extended periods.SOLUTION: A vinyl chloride resin composition according to the present invention comprises a vinyl chloride resin, a magnesium-based heat stabilizer, a zinc-based heat stabilizer, and at least one of a calcium-based heat stabilizer and a polyol, wherein the total content of the calcium-based heat stabilizer and the polyol is 0.28 pt.wt. or less per 100 pts.wt. of the vinyl chloride resin.SELECTED DRAWING: None

Description

[Technical Field]

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

[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] When vinyl chloride resins are used to produce molded articles, stable molding can be difficult because vinyl chloride resins have low thermal stability and are prone to thermal decomposition due to the elimination of hydrogen chloride during heat molding, which can result in reduced mechanical strength and discoloration of the resulting molded articles.

[0004] To enhance the thermal stability of vinyl chloride resins, heat stabilizers are sometimes used together with vinyl chloride resins. Known examples of such heat stabilizers include tin-based heat stabilizers, calcium-zinc-based heat stabilizers, barium-zinc-based heat stabilizers, and barium-cadmium-based heat stabilizers.

[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. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-217358 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, an organotin-based heat stabilizer having a hydrogen chloride scavenging function is used, which inhibits decomposition of the vinyl chloride-based resin and can increase the thermal stability of the vinyl chloride-based resin composition to a certain extent.

[0008] However, further improvement in the thermal stability of vinyl chloride resin compositions is desired. Furthermore, when a molded article is obtained using a conventional vinyl chloride resin composition, if the molding operation is carried out continuously for a long period of time (e.g., 5 hours or more), components in the vinyl chloride resin composition may adhere to the surface of the mold (plate-out may occur). Plate-out may result in poor appearance, such as scratches or streaks, on the surface of the obtained molded article, or may reduce the productivity of vinyl chloride resin molded articles. This phenomenon is particularly likely to occur when the vinyl chloride resin composition contains a calcium-containing heat stabilizer or polyol.

[0009] An object of the present invention is to provide a vinyl chloride resin composition that can improve thermal stability during hot molding and can suppress the occurrence of plate-out when molded articles are produced continuously over 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. [Means for solving the problem]

[0010] This specification discloses the following vinyl chloride resin composition and vinyl chloride resin molded article.

[0011] Item 1. A vinyl chloride resin composition comprising a vinyl chloride resin, a magnesium-based heat stabilizer, a zinc-based heat stabilizer, a calcium-based heat stabilizer, and at least one of a polyol, wherein the total content of the calcium-based heat stabilizer and the polyol is 0.28 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

[0012] Item 2. The vinyl chloride resin composition according to Item 1, wherein the magnesium-based heat stabilizer includes hydrotalcite.

[0013] Item 3. The vinyl chloride resin composition according to Item 2, wherein the content of the hydrotalcite is 0.25 parts by weight or more per 100 parts by weight of the vinyl chloride resin.

[0014] Item 4. The vinyl chloride resin composition according to Item 2 or 3, wherein the content of the hydrotalcite is 5.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

[0015] Item 5. The vinyl chloride resin composition according to any one of Items 1 to 4, wherein the zinc-based heat stabilizer includes zinc stearate.

[0016] Item 6. The vinyl chloride resin composition according to Item 5, wherein the content of the zinc stearate is 5.0 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

[0017] Item 7. The vinyl chloride resin composition according to Item 5 or 6, wherein the content of the zinc stearate is 0.50 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

[0018] Item 8. The vinyl chloride resin composition according to any one of Items 1 to 7, wherein the calcium-based heat stabilizer includes calcium stearate.

[0019] Item 9. The vinyl chloride resin composition according to any one of Items 1 to 8, wherein the polyol contains dipentaerythritol or a salt thereof.

[0020] Item 10. The vinyl chloride resin composition according to any one of Items 1 to 9, wherein the vinyl chloride resin composition does not contain a filler or contains 15.0 parts by weight or less of a filler per 100 parts by weight of the vinyl chloride resin.

[0021] Item 11. The vinyl chloride resin composition according to Item 10, wherein the vinyl chloride resin composition does not contain a filler or contains 8.0 parts by weight or less of a filler per 100 parts by weight of the vinyl chloride resin.

[0022] Item 12. The vinyl chloride resin composition according to Item 10 or 11, wherein the filler contains calcium carbonate.

[0023] Item 13. 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 12. [Effects of the Invention]

[0024] The vinyl chloride resin composition according to the present invention comprises a vinyl chloride resin, a magnesium-based heat stabilizer, a zinc-based heat stabilizer, a calcium-based heat stabilizer, and at least one of a polyol. In the vinyl chloride resin composition according to the present invention, the total content of the calcium-based heat stabilizer and the polyol is 0.28 parts by weight or less per 100 parts by weight of the vinyl chloride resin. Because the vinyl chloride resin composition according to the present invention has the above-mentioned configuration, it is possible to improve thermal stability during hot molding and to suppress the occurrence of plate-out when molded articles are produced continuously over a long period of time. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention will be described in detail below.

[0026] (Vinyl chloride resin composition) The vinyl chloride resin composition according to the present invention comprises a vinyl chloride resin, a magnesium-based heat stabilizer, a zinc-based heat stabilizer, a calcium-based heat stabilizer, and at least one of a polyol, wherein the total content of the calcium-based heat stabilizer and the polyol is 0.28 parts by weight or less per 100 parts by weight of the vinyl chloride resin.

[0027] The vinyl chloride resin composition contains a calcium-based heat stabilizer or a polyol. The vinyl chloride resin composition may contain a calcium-based heat stabilizer, may contain a polyol, or may contain both a calcium-based heat stabilizer and a polyol. The vinyl chloride resin composition may contain a vinyl chloride resin, a magnesium-based heat stabilizer, a zinc-based heat stabilizer, and a calcium-based heat stabilizer. The vinyl chloride resin composition may contain a vinyl chloride resin, a magnesium-based heat stabilizer, a zinc-based heat stabilizer, and a polyol. The vinyl chloride resin composition may contain a vinyl chloride resin, a magnesium-based heat stabilizer, a zinc-based heat stabilizer, a calcium-based heat stabilizer, and a polyol.

[0028] It is difficult to sufficiently improve the thermal stability of conventional vinyl chloride resin compositions. Furthermore, when a molded article is obtained using a conventional vinyl chloride resin composition, if the molded article is continuously produced for a long period of time (e.g., 5 hours or more), components in the vinyl chloride resin composition may adhere to the surface of the mold (plate-out may occur). Plate-out may result in poor appearance, such as fading or streaks, on the surface of the obtained vinyl chloride resin molded article, or may reduce the productivity of the vinyl chloride resin molded article. This phenomenon is particularly likely to occur when the vinyl chloride resin composition contains a calcium-containing heat stabilizer or polyol.

[0029] Furthermore, when the vinyl chloride resin composition contains a heat stabilizer containing magnesium or zinc, discoloration such as reddish or yellowish may occur in the obtained vinyl chloride resin molded article.

[0030] On the other hand, since the vinyl chloride resin composition according to the present invention has the above-mentioned features, it is possible to improve the thermal stability during hot molding and to suppress the occurrence of plate-out when molded articles are produced continuously over a long period of time. As a result, it is possible to suppress the occurrence of poor appearance such as fading and streaks on the surface of the obtained vinyl chloride resin molded article, and it is possible to increase the productivity of vinyl chloride resin molded articles. Furthermore, since the vinyl chloride resin composition according to the present invention has the above-mentioned features, it is possible to suppress the occurrence of discoloration such as reddish or yellowish in the obtained vinyl chloride resin molded article.

[0031] 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.

[0032] Hereinafter, each component contained in the vinyl chloride resin composition will be described.

[0033] <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 resins may be used alone or in combination of two or more.

[0034] 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; cyano group-containing compounds such as acrylonitrile; carboxyl group-containing compounds such as itaconic acid, maleic acid, and fumaric acid; 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.

[0035] 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.

[0036] Examples of the polymers and copolymers other than vinyl chloride include copolymers of α-olefin compounds and vinyl ester compounds, such as ethylene-vinyl acetate copolymer; copolymers of α-olefin compounds, vinyl ester compounds, and carbon monoxide, such as ethylene-vinyl acetate-carbon monoxide copolymer; copolymers of α-olefin compounds and alkyl (meth)acrylate compounds, such as ethylene-methyl methacrylate copolymer and ethylene-ethyl acrylate copolymer; and copolymers of α-olefin compounds, alkyl (meth)acrylate compounds, 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 in combination of two or more.

[0037] 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.

[0038] 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.

[0039] The average degree of polymerization of the vinyl chloride resin is preferably 500 or more, more preferably 600 or more, and preferably 2000 or less, more preferably 1200 or less, and even more preferably 900 or less. When the average degree of polymerization 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, 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 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] The chlorinated vinyl chloride resin is preferably obtained by polymerizing the vinyl chloride monomer or the vinyl chloride monomer and 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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 lower limit, the heat resistance of the resulting 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 upper limit, the moldability of the vinyl chloride resin composition can be improved, and the impact resistance and surface smoothness of the resulting vinyl chloride resin molded article can be improved.

[0049] 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.

[0050] 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 preferably 99.9% by weight or less, more preferably 99.5% by weight or less, and even more preferably 99.0% 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.

[0051] <Heat stabilizer> The vinyl chloride resin composition according to the present invention contains a 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.

[0052] The vinyl chloride resin composition contains, as a heat stabilizer, at least one of a magnesium-based heat stabilizer, a zinc-based heat stabilizer, a calcium-based heat stabilizer, and a polyol.

[0053] The vinyl chloride resin composition contains a specific heat stabilizer in combination, which can sufficiently enhance the thermal stability during hot molding and prevent the resulting vinyl chloride resin molded article from turning black. Furthermore, despite the use of a calcium-based heat stabilizer or a polyol, the vinyl chloride resin composition can suppress plate-out when molded articles are continuously produced over an extended period of time. Furthermore, despite the use of a magnesium-based heat stabilizer and a zinc-based heat stabilizer, the vinyl chloride resin composition can suppress discoloration, such as reddish or yellowish discoloration, in the resulting vinyl chloride resin molded article.

[0054] <Magnesium-based heat stabilizer> The magnesium-based heat stabilizer, when used in combination with the zinc-based heat stabilizer, can effectively improve the thermal stability during hot molding. Furthermore, since the vinyl chloride resin composition contains the magnesium-based heat stabilizer, the resulting vinyl chloride resin molded article can be prevented from discoloring to black.

[0055] Examples of the magnesium-based heat stabilizer include magnesium oxide, magnesium stearate, magnesium hydroxide, hydrotalcite, etc. The magnesium-based heat stabilizer may be used alone or in combination of two or more.

[0056] From the viewpoint of further improving the thermal stability during heat molding, the magnesium-based thermal stabilizer preferably contains hydrotalcite.

[0057] The above hydrotalcite is not particularly limited. From the perspective of further enhancing the thermal stability during heat molding, it is preferable that the above hydrotalcite contains magnesium and aluminum, and more preferably contains magnesium, zinc, and aluminum. In this specification, when the above hydrotalcite contains zinc, the above hydrotalcite is classified as a magnesium-based heat stabilizer. When the above hydrotalcite contains zinc, the above vinyl chloride-based resin composition contains the above hydrotalcite and a zinc-based heat stabilizer other than the above hydrotalcite.

[0058] From the perspective of further enhancing the thermal stability during heat molding and improving the heat resistance of the obtained vinyl chloride-based resin molded body, it is preferable that the above hydrotalcite is a compound represented by the following formula (1).

[0059] {(Mg) x (Zn) y}(Al) z (OH)2(A n- ) x / n·mH2O ···(1)

[0060] In the above formula (1), A n- represents an n-valent interlayer anion. In the above formula (1), x, y, and z satisfy 0 < x < 1, 0 ≤ y < 1, 0.2 ≤ z ≤ 0.4, and x + y + z = 1, and satisfy (x + y) / z ≤ 2.2. In the above formula (1), n represents an integer from 1 to 4, and m represents an integer of 0 or more.

[0061] In the above formula (1), A n- includes hydroxide ions (OH - ), carbonate ions (CO3 2- ), sulfate ions (SO4 2- ), etc. In the above formula (1), A n- may be only one kind or two or more kinds. From the perspective of enhancing the reactivity between hydrogen chloride generated by the decomposition of the vinyl chloride-based resin and the hydrotalcite, in the above formula (1), A n-Preferably, the ions are hydroxide ions, carbonate ions, or sulfate ions, and more preferably carbonate ions.

[0062] The hydrotalcite may be hydrotalcite from which water of crystallization has been dehydrated.

[0063] The hydrotalcite may be a natural product or a synthetic product. The hydrotalcite may be one whose surface is coated with a coating agent. Examples of the coating agent include higher fatty acids such as stearic acid, higher fatty acid metal salts such as alkali metal oleates, organic sulfonic acid metal salts such as alkali metal dodecylbenzenesulfonates, higher fatty acid amides, higher fatty acid esters, and waxes.

[0064] The hydrotalcite may be a commercially available product. Examples of commercially available hydrotalcite include Alkamiser 1, Alkamiser 2, Alkamiser P93, Alkamiser 5, Alkamiser 7, and DHT-4A (all manufactured by Kyowa Chemical Industry Co., Ltd.).

[0065] The content of the magnesium-based heat stabilizer in 100% by weight of the vinyl chloride resin composition is preferably 0.10% by weight or more, more preferably 0.20% by weight or more, even more preferably 0.25% by weight or more, and preferably 4.2% by weight or less, more preferably 3.8% by weight or less, and even more preferably 3.4% by weight or less. When the content of the magnesium-based heat stabilizer is equal to or greater than the lower limit, the thermal stability during thermoforming can be further improved, and the resulting vinyl chloride resin molded article can be prevented from discoloring to black. When the content of the magnesium-based heat stabilizer is equal to or less than the upper limit, the resulting vinyl chloride resin molded article can be prevented from discoloring to red or yellow, for example.

[0066] The content of the hydrotalcite in 100% by weight of the vinyl chloride resin composition is preferably 0.10% by weight or more, more preferably 0.20% by weight or more, even more preferably 0.25% by weight or more, and is preferably 4.2% by weight or less, more preferably 3.8% by weight or less, and even more preferably 3.4% by weight or less. When the content of the hydrotalcite is equal to or greater than the lower limit, the thermal stability during hot molding can be further improved, and the resulting vinyl chloride resin molded article can be prevented from discoloring to black. When the content of the hydrotalcite is equal to or less than the upper limit, the resulting vinyl chloride resin molded article can be prevented from discoloring to reddish or yellowish, for example.

[0067] The content of the magnesium-based heat stabilizer relative to 100 parts by weight of the vinyl chloride resin is preferably 0.10 parts by weight or more, more preferably 0.20 parts by weight or more, even more preferably 0.25 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 magnesium-based heat stabilizer is equal to or greater than the lower limit, the thermal stability during hot molding can be further improved, and the resulting vinyl chloride resin molded article can be prevented from discoloring to black. When the content of the magnesium-based heat stabilizer is equal to or less than the upper limit, the occurrence of discoloration such as reddish or yellowish tinge can be suppressed in the resulting vinyl chloride resin molded article.

[0068] The content of the hydrotalcite is preferably 0.10 parts by weight or more, more preferably 0.20 parts by weight or more, even more preferably 0.25 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, relative to 100 parts by weight of the vinyl chloride resin. When the content of the hydrotalcite is equal to or greater than the lower limit, the thermal stability during hot molding can be further improved, and the resulting vinyl chloride resin molded article can be prevented from discoloring to black. When the content of the hydrotalcite is equal to or less than the upper limit, the occurrence of discoloration such as reddish or yellowish tinge can be suppressed in the resulting vinyl chloride resin molded article.

[0069] <Zinc-based heat stabilizer> Examples of the zinc-based heat stabilizer include inorganic zinc compounds and organic acid zinc salts, etc. The zinc-based heat stabilizer may be used alone or in combination of two or more.

[0070] Examples of the inorganic zinc compound include inorganic acid zinc salts such as zinc carbonate, zinc oxide, zinc hydroxide, etc. Carbonic acid is classified as an inorganic acid.

[0071] Examples of the organic acid zinc salts include zinc 2-ethylhexylate, zinc stearate, zinc 12-hydroxystearate, zinc montanate, zinc oleate, zinc linoleate, zinc adipate, and zinc phthalate.

[0072] From the viewpoint of further improving the thermal stability during heat molding, the zinc-based heat stabilizer preferably contains an organic acid zinc salt, and more preferably contains zinc stearate.

[0073] The content of the zinc-based heat stabilizer in 100% by weight of the vinyl chloride resin composition is preferably 0.10% by weight or more, more preferably 0.20% by weight or more, even more preferably 0.30% by weight or more, and is preferably 4.2% by weight or less, more preferably 2.5% by weight or less, and even more preferably 1.7% by weight or less. When the content of the zinc-based heat stabilizer is equal to or greater than the lower limit, the thermal stability during hot molding can be further improved, and the resulting vinyl chloride resin molded article can be prevented from discoloring to black. When the content of the zinc-based heat stabilizer is equal to or less than the upper limit, the resulting vinyl chloride resin molded article can be prevented from discoloring to red or yellow, for example.

[0074] When the zinc-based heat stabilizer contains zinc stearate, the content of the zinc stearate in 100% by weight of the vinyl chloride resin composition is preferably 0.10% by weight or more, more preferably 0.20% by weight or more, even more preferably 0.30% by weight or more, and preferably 4.2% by weight or less, more preferably 2.5% by weight or less, and even more preferably 1.7% by weight or less. When the content of zinc stearate is above the lower limit, the thermal stability during heat molding can be further improved, and the resulting vinyl chloride resin molded article can be prevented from discoloring to black. When the content of zinc stearate is below the upper limit, the occurrence of discoloration such as reddish or yellowish tinge can be suppressed in the resulting vinyl chloride resin molded article.

[0075] The content of the zinc-based heat stabilizer relative to 100 parts by weight of the vinyl chloride resin is preferably 0.10 parts by weight or more, more preferably 0.15 parts by weight or more, even more preferably 0.20 parts by weight or more, and is preferably 5.0 parts by weight or less, more preferably 3.0 parts by weight or less, even more preferably 2.0 parts by weight or less, particularly preferably 1.0 parts by weight or less, and most preferably 0.5 parts by weight or less. When the content of the zinc-based heat stabilizer is above the lower limit, the thermal stability during hot molding can be further improved, and the resulting vinyl chloride resin molded article can be prevented from discoloring to black. When the content of the zinc-based heat stabilizer is below the upper limit, the occurrence of discoloration such as reddish or yellowish tinge can be suppressed in the resulting vinyl chloride resin molded article.

[0076] When the zinc-based heat stabilizer contains zinc stearate, the content of the zinc stearate is preferably at least 0.10 parts by weight, more preferably at least 0.15 parts by weight, even more preferably at least 0.20 parts by weight, and preferably at most 5.0 parts by weight, more preferably at most 3.0 parts by weight, even more preferably at most 2.0 parts by weight, particularly preferably at most 1.0 part by weight, and most preferably at most 0.50 parts by weight, per 100 parts by weight of the vinyl chloride resin. When the content of the zinc stearate is at least the lower limit, the thermal stability during thermoforming can be further improved, and the resulting vinyl chloride resin molded article can be prevented from discoloring to black. When the content of the zinc stearate is at most the upper limit, the occurrence of discoloration such as reddish or yellowish tinges can be suppressed in the resulting vinyl chloride resin molded article.

[0077] <Calcium-based heat stabilizer> The calcium-based heat stabilizer, when used in combination with the zinc-based heat stabilizer, can effectively improve the thermal stability during hot molding. Furthermore, since the vinyl chloride resin composition contains the calcium-based heat stabilizer or the polyol, discoloration such as reddish or yellowish can be suppressed in the vinyl chloride resin molded article obtained, despite the use of the magnesium-based heat stabilizer and the zinc-based heat stabilizer.

[0078] Examples of the calcium-based heat stabilizer include organic acid calcium salts and inorganic calcium salts. The calcium-based heat stabilizer may be used alone or in combination of two or more.

[0079] Examples of the organic acid calcium salts include calcium 2-ethylhexylate, calcium stearate, calcium 12-hydroxystearate, calcium montanate, calcium oleate, calcium linoleate, calcium adipate, and calcium phthalate.

[0080] From the viewpoint of further improving the thermal stability during heat molding, the calcium-based thermal stabilizer preferably contains an organic acid calcium salt, and more preferably contains calcium stearate.

[0081] When the vinyl chloride resin composition contains the calcium-based heat stabilizer, the content of the calcium-based heat stabilizer 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 0.07% by weight or more, and preferably 0.30% by weight or less, more preferably 0.25% by weight or less, and even more preferably 0.20% by weight or less. When the content of the calcium-based heat stabilizer is equal to or greater than the lower limit, the thermal stability during thermoforming can be further improved, and discoloration such as reddish or yellowish can be suppressed in the obtained vinyl chloride resin molded article. When the content of the calcium-based heat stabilizer is equal to or less than the upper limit, the occurrence of plate-out can be more effectively suppressed when molded articles are continuously produced over a long period of time.

[0082] When the vinyl chloride resin composition contains the calcium-based heat stabilizer, the content of the calcium-based heat stabilizer is preferably at least 0.01 parts by weight, more preferably at least 0.05 parts by weight, and preferably at most 0.28 parts by weight, more preferably at most 0.25 parts by weight, even more preferably at most 0.20 parts by weight, and particularly preferably at most 0.15 parts by weight, per 100 parts by weight of the vinyl chloride resin. When the content of the calcium-based heat stabilizer is at least the lower limit, thermal stability during thermoforming can be further improved, and discoloration such as reddish or yellowish discoloration can be suppressed in the resulting vinyl chloride resin molded article. When the content of the calcium-based heat stabilizer is at most the upper limit, plate-out can be more effectively suppressed when molded articles are continuously produced over a long period of time.

[0083] When the vinyl chloride resin composition contains calcium stearate, the content of calcium stearate is preferably at least 0.01 parts by weight, more preferably at least 0.05 parts by weight, and preferably at most 0.28 parts by weight, more preferably at most 0.25 parts by weight, even more preferably at most 0.20 parts by weight, and particularly preferably at most 0.15 parts by weight, relative to 100 parts by weight of the vinyl chloride resin. When the content of calcium stearate is at least the above-mentioned lower limit, the thermal stability during hot molding can be further improved, and discoloration such as reddish or yellowish can be suppressed in the obtained vinyl chloride resin molded article. When the content of calcium stearate is at most the above-mentioned upper limit, the occurrence of plate-out can be more effectively suppressed when molded articles are continuously produced over a long period of time.

[0084] <Polyol> The vinyl chloride resin composition contains a calcium-based heat stabilizer or a polyol, and therefore, discoloration such as reddish or yellowish can be suppressed in the vinyl chloride resin molded article obtained, despite the use of a magnesium-based heat stabilizer and a zinc-based heat stabilizer.

[0085] Examples of the polyol include dipentaerythritol, glycerin, diglycerin, and tris(2-hydroxyethyl)isocyanurate. The polyol may be a salt of dipentaerythritol. The polyol may be used alone or in combination of two or more.

[0086] Examples of the salts of dipentaerythritol include dipentaerythritol adipate (a partial ester of dipentaerythritol with adipic acid), dipentaerythritol hexastearate (a stearate of dipentaerythritol), and the like.

[0087] From the viewpoint of more effectively suppressing discoloration such as reddishness and yellowishness in the vinyl chloride resin molded article obtained, the polyol preferably contains dipentaerythritol or a salt thereof. From the viewpoint of more effectively improving thermal stability during heat molding, the polyol particularly preferably contains dipentaerythritol. From the viewpoint of more effectively suppressing plate-out when molded articles are continuously produced over a long period of time, the polyol more preferably contains a salt of dipentaerythritol, and particularly preferably contains dipentaerythritol adipate.

[0088] The total content of the calcium-based heat stabilizer and the polyol 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 0.07% by weight or more, and preferably 0.35% by weight or less, more preferably 0.25% by weight or less, and even more preferably 0.13% by weight or less. When the total content of the calcium-based heat stabilizer and the polyol is equal to or greater than the lower limit, the thermal stability during thermoforming can be further improved, and discoloration such as reddish or yellowish can be suppressed in the obtained vinyl chloride resin molded article. When the total content of the calcium-based heat stabilizer and the polyol is equal to or less than the upper limit, the occurrence of plate-out can be more effectively suppressed when molded articles are continuously produced over a long period of time. The total content of the calcium-based heat stabilizer and the polyol indicates the content of the calcium-based heat stabilizer when the vinyl chloride resin composition contains the calcium-based heat stabilizer but not the polyol, and indicates the content of the polyol when the vinyl chloride resin composition contains the polyol but not the calcium-based heat stabilizer (the same applies hereinafter).

[0089] When the vinyl chloride resin composition contains the polyol, the content of the polyol, based on 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 0.07% by weight or more, and preferably 0.20% by weight or less, more preferably 0.16% by weight or less, and even more preferably 0.13% by weight or less. When the content of the polyol is equal to or greater than the lower limit, the thermal stability during hot molding can be further improved, and discoloration such as reddish or yellowish can be suppressed in the obtained vinyl chloride resin molded article. When the content of the polyol is equal to or less than the upper limit, the occurrence of plate-out can be more effectively suppressed when molded articles are continuously produced over a long period of time.

[0090] When the vinyl chloride resin composition contains the polyol, the content of the polyol is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, and preferably 0.28 parts by weight or less, more preferably 0.25 parts by weight or less, even more preferably 0.20 parts by weight or less, and particularly preferably 0.15 parts by weight or less, relative to 100 parts by weight of the vinyl chloride resin. When the content of the polyol is equal to or greater than the lower limit, the thermal stability during hot molding can be further improved, and discoloration such as reddish or yellowish discoloration can be suppressed in the obtained vinyl chloride resin molded article. When the content of the polyol is equal to or less than the upper limit, the occurrence of plate-out can be more effectively suppressed when molded articles are continuously produced over a long period of time.

[0091] The total content of the calcium-based heat stabilizer and the polyol is 0.28 parts by weight or less per 100 parts by weight of the vinyl chloride resin. The total content of the calcium-based heat stabilizer and the polyol 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, and preferably 0.25 parts by weight or less, more preferably 0.20 parts by weight or less, and even more preferably 0.15 parts by weight or less per 100 parts by weight of the vinyl chloride resin. When the total content of the calcium-based heat stabilizer and the polyol is above the lower limit, the thermal stability during thermoforming can be further improved, and discoloration such as reddish or yellowish discoloration can be suppressed in the resulting vinyl chloride resin molded article. When the total content of the calcium-based heat stabilizer and the polyol is below the upper limit, the occurrence of plate-out can be more effectively suppressed when molded articles are continuously produced over a long period of time.

[0092] <Other ingredients> The vinyl chloride resin composition may contain additives as needed. Examples of the additives include thermal 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.

[0093] Examples of the heat stabilization aid include β-diketone compounds, epoxidized soybean oil, phosphate esters, hydrotalcite, and zeolites. The heat stabilization aids may be used alone or in combination of two or more. Examples of the β-diketone compounds include acetylacetone, dibenzoylmethane, steroylbenzoylmethane, and dihydroacetic acid.

[0094] 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.

[0095] 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, polyethylene 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.

[0096] 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. The processing aids may be used alone or in combination of two or more.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] Examples of the filler include calcium carbonate, talc, etc. The filler may be used alone or in combination of two or more.

[0102] From the viewpoint of cost reduction, the filler preferably contains calcium carbonate.

[0103] The content of the filler in 100% by weight of the vinyl chloride resin composition is preferably 30% by weight or less, more preferably 15% by weight or less, even more preferably 10% by weight or less, and particularly preferably 3% by weight or less. When the content of the filler is equal to or less than the above upper limit, the thermal stability during heat molding can be further improved. There is no particular limitation on the lower limit of the content of the filler in 100% by weight of the vinyl chloride resin composition. The content of the filler in 100% by weight of the vinyl chloride resin composition may be 0% by weight or more, or may be 0.1% by weight or more.

[0104] The vinyl chloride resin composition preferably does not contain the filler or contains 15.0 parts by weight or less of the filler per 100 parts by weight of the vinyl chloride resin. The vinyl chloride resin composition more preferably does not contain the filler or contains 8.0 parts by weight or less of the filler per 100 parts by weight of the vinyl chloride resin. When the vinyl chloride resin composition contains the filler, the content of the filler per 100 parts by weight of the vinyl chloride resin is preferably 15.0 parts by weight or less, more preferably 10.0 parts by weight or less, even more preferably 8.0 parts by weight or less, particularly preferably 6.0 parts by weight or less, and most preferably 5.0 parts by weight or less. When the content of the filler is below the upper limit, thermal stability during hot molding can be further improved. When the vinyl chloride resin composition contains the filler, there is no particular lower limit on the content of the filler per 100 parts by weight of the vinyl chloride resin. The content of the filler may be more than 0 part by weight, 0.1 part by weight or more, or 0.5 part by weight or more, relative to 100 parts by weight of the vinyl chloride resin. From the viewpoint of further improving the thermal stability during hot molding, it is most preferable that the vinyl chloride resin composition does not contain the filler.

[0105] 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. The colorant may be used alone or in combination of two or more.

[0106] From the viewpoint of improving the design of the resulting vinyl chloride resin molded article, the vinyl chloride resin composition preferably contains a colorant. The colorant may be a black colorant, a red colorant, a blue colorant, a yellow colorant, or a white colorant. The colorant may also be a gray colorant.

[0107] 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 0.10% 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 between the lower limit and the upper limit, it is easy to appropriately color the vinyl chloride resin molded article.

[0108] The content of the colorant relative to 100 parts by weight of the vinyl chloride resin is preferably 0.02 parts by weight or more, more preferably 0.05 parts by weight or more, even more preferably 0.10 parts by weight or more, and is preferably 10 parts by weight or less, more preferably 8.0 parts by weight or less, even more preferably 6.0 parts by weight or less, and particularly preferably 4.0 parts by weight or less. When the content of the colorant is at least the above lower limit and at most the above upper limit, it is easy to appropriately color the vinyl chloride resin molded article.

[0109] The plasticizer may be added to improve processability during molding. Since the addition of a plasticizer can 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. The plasticizer may be used alone or in combination of two or more.

[0110] (Vinyl chloride resin molded body) 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.

[0111] 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.

[0112] Examples of the shape of the vinyl chloride resin molded article include a pipe, a plate, a container, and the like. The vinyl chloride resin molded article is preferably in the form of a pipe (tube). The vinyl chloride resin molded article is preferably used as a vinyl chloride resin pipe. The vinyl chloride resin molded article is also preferably used as a rain gutter.

[0113] 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.

[0114] Examples of molding machines used for molding include a single-screw extruder, a twin-screw counter-rotating parallel extruder, a twin-screw counter-rotating conical extruder, and a twin-screw co-rotating extruder, etc. The heating temperature when molding using the above molding machines is preferably 80°C or higher and preferably 140°C or lower.

[0115] 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 extrusion molded article of the vinyl chloride resin composition described above.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] The following materials were prepared:

[0120] PVC resin: Vinyl chloride resin (Tokuyama Sekisui Kogyo Co., Ltd. "TS-1000R", average degree of polymerization: 1000)

[0121] Heat stabilizer: Magnesium-based heat stabilizer (Kyowa Chemical Industry Co., Ltd.'s "Alcamizer 2") Zinc-based heat stabilizer (NOF Corporation "GF-200") Calcium-based heat stabilizer (Sakai Chemical Industry Co., Ltd. "SC-100") Polyol (TCI "Dipentaerythritol") Polyol (AFT "Dipentaerythritol adipate")

[0122] Other Ingredients: Heat stabilization aid (TCI "acetylacetone") Heat stabilization aid (TCI "Dibenzoylmethane") Antioxidant (hindered phenol antioxidant, BASF "Irganox 1010") Filler (calcium carbonate, Shiraishi Calcium Co., Ltd. "W-305S") Lubricant (polyethylene wax, Nippon Seiro "LUVAX2191") Lubricant (polyethylene wax, Mitsui Chemicals "HW4202E") Lubricant (polyethylene wax, Mitsui Chemicals "HW220RKT") Lubricant (ester wax, Riken Vitamin "SG22") Lubricant (ester wax, Emery "G21") Colorant (pigment (organic pigment, gray), Dainichiseika Color & Chemicals Mfg. Co., Ltd. "PMP SK1422")

[0123] Example 1 Preparation of vinyl chloride resin composition: The materials shown in Table 1 were blended in the amounts shown in Table 1, and the mixture was stirred and mixed at 110° C. for 5 minutes using a Henschel mixer (manufactured by Kawada Kogyo Co., Ltd.) to obtain a vinyl chloride resin composition.

[0124] (Examples 2 to 4 and Comparative Examples 1 to 6) Vinyl chloride resin compositions were obtained in the same manner as in Example 1, except that the formulation of the vinyl chloride resin composition was changed as shown in Tables 1 and 2.

[0125] (evaluation) (1) Thermal stability The obtained vinyl chloride resin composition was kneaded and molded under the following conditions to obtain a sheet (vinyl chloride resin molded article) having a thickness of 3.0 mm.

[0126] [Mixing conditions] Mixing roll: Yasuda Seiki Manufacturing Co., Ltd. Roll temperature: 200℃ Roll time: 1 minute (after wrapping)

[0127] [Molding conditions] Press machine: manufactured by Kodaira Manufacturing Co., Ltd. Press temperature: 200℃ Pressurization time: 10 minutes Cooling time: 3 minutes

[0128] During the heating and pressurizing process for molding a vinyl chloride resin composition, the sheet placed in the press was visually inspected for discoloration every 30 seconds, and the sheet was removed when it turned black. The sheet was visually inspected for discoloration for 10 minutes. Thermal stability was evaluated according to the following criteria:

[0129] [Criteria for determining thermal stability] ○○: No black discoloration after 10 minutes ○: Turns black after 8 to 10 minutes ×: Turns black after 7 minutes and 30 seconds or less

[0130] (2) Suppression of plate-out occurrence The obtained vinyl chloride resin composition was molded under the following conditions to obtain a sheet (vinyl chloride resin molded article) having a thickness of 3.0 mm.

[0131] [Molding conditions] Extruder: Plastics Engineering Research Institute "Twin-screw extruder SLM50" Extrusion rate: 30 kg / hour Resin temperature: 190℃ Continuous extrusion molding time: 5 hours

[0132] After 5 hours of continuous extrusion molding, the mold was disassembled, and the presence or absence of components in the vinyl chloride resin composition adhering to the surface of the flow path in the mold and the presence or absence of streaks on the surface of the sheet (vinyl chloride resin molded article) were visually confirmed. The suppression of plate-out occurrence was evaluated according to the following criteria.

[0133] [Criteria for determining plate-out suppression] ○○: No adhesion on the surface of the mold flow path ○: A small amount of adhesion on the surface of the mold flow path ×: A large amount of adhesion was observed on the surface of the flow path of the mold, or streaks were observed on the surface of the sheet (vinyl chloride resin molded product).

[0134] The compositions of the vinyl chloride resin compositions and the results are shown in Tables 1 and 2. In Comparative Examples 3 to 6, extrusion molding was not possible.

[0135] Table 1

[0136] Table 2

Claims

1. The composition contains a vinyl chloride resin, a magnesium-based heat stabilizer, a zinc-based heat stabilizer, a calcium-based heat stabilizer, and at least one of a polyol, a total content of the calcium-based heat stabilizer and the polyol being 0.28 parts by weight or less relative to 100 parts by weight of the vinyl chloride resin;

2. 2. The vinyl chloride resin composition according to claim 1, wherein the magnesium-based heat stabilizer comprises hydrotalcite.

3. 3. The vinyl chloride resin composition according to claim 2, wherein the content of the hydrotalcite is 0.25 parts by weight or more based on 100 parts by weight of the vinyl chloride resin.

4. 4. The vinyl chloride resin composition according to claim 2, wherein the content of the hydrotalcite is 5.0 parts by weight or less based on 100 parts by weight of the vinyl chloride resin.

5. 3. The vinyl chloride resin composition according to claim 1, wherein the zinc-based heat stabilizer comprises zinc stearate.

6. 6. The vinyl chloride resin composition according to claim 5, wherein the content of the zinc stearate is 5.0 parts by weight or less based on 100 parts by weight of the vinyl chloride resin.

7. 7. The vinyl chloride resin composition according to claim 6, wherein the content of the zinc stearate is 0.50 parts by weight or less based on 100 parts by weight of the vinyl chloride resin.

8. 3. The vinyl chloride resin composition according to claim 1, wherein the calcium-based heat stabilizer comprises calcium stearate.

9. 3. The vinyl chloride resin composition according to claim 1, wherein the polyol comprises dipentaerythritol or a salt thereof.

10. 2. The vinyl chloride resin composition according to claim 1, wherein the vinyl chloride resin composition does not contain a filler or contains 15.0 parts by weight or less of a filler per 100 parts by weight of the vinyl chloride resin.

11. 11. The vinyl chloride resin composition according to claim 10, wherein the vinyl chloride resin composition does not contain a filler or contains 8.0 parts by weight or less of a filler per 100 parts by weight of the vinyl chloride resin.

12. The vinyl chloride resin composition according to claim 10 or 11, wherein the filler comprises calcium carbonate.

13. A vinyl chloride resin molded article, which is a molded article of the vinyl chloride resin composition according to claim 1 or 2.

Images