Vinyl chloride resin composition, method for producing vinyl chloride resin composition, vinyl chloride resin molding, and vinyl chloride resin pipe

Abstract

To provide a vinyl chloride resin composition that allows suppression of appearance defects, improvement of heat resistance, and enhancement of impact resistance in a produced vinyl chloride resin molding.SOLUTION: A vinyl chloride resin composition according to the present invention comprises a crushed material of a vinyl chloride resin molding and a dicarboxylate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a vinyl chloride resin composition containing a pulverized vinyl chloride resin molded article. The present invention also relates to a method for producing the vinyl chloride resin composition. The present invention also relates to a vinyl chloride resin molded article and a vinyl chloride resin pipe using the vinyl chloride resin composition. [Background technology]

[0002] Vinyl chloride resins have excellent mechanical strength, weather resistance, heat resistance, and chemical resistance, and are therefore processed into various molded articles such as pipes, plates, and containers, and are used in many fields.

[0003] From the viewpoint of resource conservation and cost reduction, there is a demand for recycling of vinyl chloride resin molded articles collected from the public (such as discarded articles). However, when vinyl chloride resin molded articles collected from the public are crushed and reused, there is a problem that the thermal stability during remolding decreases. As a result, molded articles (recycled articles) obtained by remolding crushed vinyl chloride resin molded articles may have poor appearance such as discoloration or fading, or may have reduced heat resistance or mechanical strength.

[0004] In order to solve such problems, a heat stabilizer is sometimes added to the pulverized vinyl chloride resin molded articles when they are recycled.

[0005] Patent Document 1 below discloses a method for manufacturing a resin sash, including the steps of recovering used resin pipes containing polyvinyl chloride as a main component, crushing the used resin pipes to produce a recycled material, mixing the recycled material with an additive containing a torque improver to produce a kneaded mixture, and extrusion molding the kneaded mixture. A heat stabilizer may be used in the method for manufacturing the resin sash. The heat stabilizer may be a lead-based heat stabilizer or a calcium-zinc-based heat stabilizer.

[0006] Patent Document 2 below discloses a molding method for recycled raw materials containing polyvinyl chloride resin. In this molding method, 0.2 parts by weight or more of a color-preventing stabilizer is added to 100 parts by weight of a mixed recycled raw material that is a mixture of recycled polyvinyl chloride resin raw materials containing a lead-based heat stabilizer and recycled polyvinyl chloride resin raw materials containing a tin-based heat stabilizer, and the resulting composition is then melt-molded. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-159468 [Patent Document 2] Japanese Patent Application Publication No. 6-107886 Summary of the Invention [Problem to be solved by the invention]

[0008] When a vinyl chloride resin composition contains a lead-based heat stabilizer or an organic acid metal salt-based heat stabilizer, such as a calcium- or zinc-based heat stabilizer, the lubricity during molding increases, which can make it difficult to apply shear energy to the pulverized vinyl chloride resin molded body. As a result, the pulverized material may not melt sufficiently, resulting in reduced impact resistance (mechanical strength) of the resulting molded body. Furthermore, tin-based heat stabilizers, such as those described in Patent Document 2, are expensive. Furthermore, lead-based heat stabilizers are widely used in waste vinyl chloride resin molded bodies collected from the market. However, since tin-based heat stabilizers generally contain sulfur, the sulfur component reacts with the lead-based heat stabilizer in the pulverized vinyl chloride resin molded body to form lead sulfide, which can cause the resulting molded body to discolor to a brownish-black or blackish-brown, resulting in poor appearance.

[0009] That is, with conventional methods for recycling vinyl chloride resin molded articles using heat stabilizers, it is difficult to suppress the occurrence of defective appearance, improve the heat resistance, and improve the impact resistance of the resulting vinyl chloride resin molded articles.

[0010] An object of the present invention is to provide a vinyl chloride resin composition that can suppress the occurrence of defective appearance, improve heat resistance, and improve impact resistance in the resulting vinyl chloride resin molded article. Another object of the present invention is to provide a method for producing the vinyl chloride resin composition, and a vinyl chloride resin molded article and a vinyl chloride resin pipe that use the vinyl chloride resin composition. [Means for solving the problem]

[0011] This specification discloses the following vinyl chloride resin composition, method for producing a vinyl chloride resin composition, vinyl chloride resin molded article, and vinyl chloride resin pipe.

[0012] Item 1. A vinyl chloride resin composition comprising a pulverized vinyl chloride resin molded article and a dicarboxylic acid salt.

[0013] Item 2. The vinyl chloride resin composition according to Item 1, further comprising a vinyl chloride resin.

[0014] Item 3. The vinyl chloride resin composition according to Item 1 or 2, wherein the content of the dicarboxylate is 0.1 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of the total content of components excluding the dicarboxylate in the vinyl chloride resin composition.

[0015] Item 4. The vinyl chloride resin composition according to any one of Items 1 to 3, wherein the dicarboxylate has 2 or more and 22 or less carbon atoms.

[0016] Item 5. The vinyl chloride resin composition according to any one of Items 1 to 4, wherein the dicarboxylate is an alkali metal dicarboxylate or an alkaline earth metal dicarboxylate.

[0017] Item 6. The vinyl chloride resin composition according to any one of Items 1 to 5, wherein the dicarboxylate is a sodium dicarboxylate.

[0018] Item 7. The vinyl chloride resin composition according to any one of Items 1 to 6, wherein the dicarboxylate is disodium adipate.

[0019] Item 8. A method for producing a vinyl chloride resin composition, comprising a mixing step of mixing a pulverized vinyl chloride resin molded body with a dicarboxylic acid salt.

[0020] Item 9. The method for producing a vinyl chloride resin composition according to Item 8, wherein the mixing step is a mixing step of mixing the pulverized vinyl chloride resin molded article, the dicarboxylic acid salt, and a vinyl chloride resin.

[0021] Item 10. The method for producing a vinyl chloride resin composition according to Item 9, wherein the mixing step comprises a first mixing step of mixing the pulverized vinyl chloride resin molded product with the dicarboxylate, and a second mixing step of mixing the vinyl chloride resin with the mixture of the pulverized vinyl chloride resin molded product and the dicarboxylate.

[0022] Item 11. A method for producing a vinyl chloride resin composition according to any one of Items 8 to 10, comprising a pulverization step of pulverizing a vinyl chloride resin molded body to obtain a pulverized product of the vinyl chloride resin molded body.

[0023] Item 12. 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 7.

[0024] Item 13. The vinyl chloride resin molded article according to Item 12, wherein the molded article is an extrusion molded article.

[0025] Item 14. A vinyl chloride resin pipe that is a single-layer pipe having a one-layer structure or a multi-layer pipe having a laminated structure of two or more layers, wherein one layer in the single-layer pipe or at least one layer in the multi-layer pipe is a molded article of the vinyl chloride resin composition according to any one of Items 1 to 7.

[0026] Item 15. The vinyl chloride resin pipe according to Item 14, wherein the single-layer pipe has a one-layer structure, and one layer in the single-layer pipe is a molded body of the vinyl chloride resin composition.

[0027] Item 16. The multi-layer pipe according to Item 14, having a laminated structure of two or more layers, wherein at least one layer of the multi-layer pipe is a molded article of the vinyl chloride resin composition.

[0028] Item 17. The vinyl chloride resin pipe according to any one of Items 14 to 16, which is a rigid vinyl chloride resin pipe. [Effects of the Invention]

[0029] The vinyl chloride resin composition according to the present invention comprises a pulverized vinyl chloride resin molded product and a dicarboxylate. The method for producing the vinyl chloride resin composition according to the present invention comprises a mixing step of mixing a pulverized vinyl chloride resin molded product with a dicarboxylate. Therefore, the vinyl chloride resin molded product obtained by the method for producing a vinyl chloride resin composition according to the present invention comprises a pulverized vinyl chloride resin molded product and a dicarboxylate. The vinyl chloride resin composition according to the present invention and the method for producing a vinyl chloride resin composition according to the present invention have the above-mentioned features, and therefore the vinyl chloride resin molded product obtained can 1) suppress the occurrence of defective appearance, 2) improve heat resistance, and 3) improve impact resistance. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a cross-sectional view schematically showing a vinyl chloride resin pipe according to a first embodiment of the present invention. [Figure 2]FIG. 2 is a cross-sectional view schematically showing a vinyl chloride resin pipe according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be described in detail below.

[0032] (Vinyl chloride resin composition) The vinyl chloride resin composition according to the present invention contains a pulverized vinyl chloride resin molded article and a dicarboxylate.

[0033] The vinyl chloride resin composition according to the present invention has the above-mentioned features, which enable 1) the occurrence of defective appearance of the resulting vinyl chloride resin molded article to be suppressed. Furthermore, the vinyl chloride resin composition according to the present invention has the above-mentioned features, which enables 2) the heat resistance of the resulting vinyl chloride resin molded article to be improved. Furthermore, the vinyl chloride resin composition according to the present invention has the above-mentioned features, which enables 3) the impact resistance of the resulting vinyl chloride resin molded article to be improved.

[0034] The vinyl chloride resin composition according to the present invention is suitable for use in recycling vinyl chloride resin molded articles, particularly in material recycling of vinyl chloride resin molded articles.

[0035] The vinyl chloride resin composition according to the present invention has the above-described features, and therefore does not require the use of a lead-based heat stabilizer. Without the use of a lead-based heat stabilizer, the toxicity of the vinyl chloride resin composition can be reduced, and harmful effects on the human body and the environment can be reduced. However, the vinyl chloride resin composition according to the present invention may contain a lead-based heat stabilizer.

[0036] The vinyl chloride resin composition according to the present invention is suitably used for obtaining a vinyl chloride resin molded article. A vinyl chloride resin molded article can be obtained using the vinyl chloride resin composition according to the present invention. The vinyl chloride resin molded article obtained using the vinyl chloride resin composition according to the present invention is a recycled vinyl chloride resin molded article (recycled product).

[0037] The vinyl chloride resin composition is preferably used to obtain a vinyl chloride resin pipe. The vinyl chloride resin composition is particularly preferably used to obtain a rigid vinyl chloride resin pipe. The vinyl chloride resin composition is preferably a vinyl chloride resin composition for a vinyl chloride resin pipe, and more preferably a vinyl chloride resin composition for a rigid vinyl chloride resin pipe.

[0038] Hereinafter, each component contained in the vinyl chloride resin composition will be described.

[0039] <Pulverized vinyl chloride resin molded body> In this specification, the pulverized vinyl chloride resin molded product refers to a substance obtained by pulverizing a molded product obtained by molding a composition containing a vinyl chloride resin. The pulverized vinyl chloride resin molded product may be a pulverized vinyl chloride resin molded product that has been used (e.g., collected from the community, etc.), or may be a pulverized vinyl chloride resin molded product that has not been used (e.g., defective products, scraps, etc.). The pulverized vinyl chloride resin molded product may be one type, or two or more types may be used in combination. The pulverized vinyl chloride resin molded product may include a pulverized vinyl chloride resin molded product that has been used and a pulverized vinyl chloride resin molded product that has not been used.

[0040] The used vinyl chloride resin molded body may be a vinyl chloride resin molded body that is a product. The unused vinyl chloride resin molded body may be a vinyl chloride resin molded body that has not been used as a product but has been produced to obtain a product. The unused vinyl chloride resin molded body may be a vinyl chloride resin molded body that has not been used as a product and has been collected. The vinyl chloride resin molded body and its pulverized product are preferably materials (non-new materials) that have been used to obtain a product. The materials used to obtain the product include materials that have been used as products. Vinyl chloride resin molded bodies and their pulverized products that are collected from the community, as well as vinyl chloride resin molded bodies and their pulverized products that are defective products and scraps, are different from new materials that have never been used to obtain a product. By using the pulverized vinyl chloride resin molded body, it is possible to eliminate or reduce the number of vinyl chloride resin molded bodies that are discarded, thereby significantly reducing the environmental impact.

[0041] The use of the vinyl chloride resin molded article is not particularly limited. The vinyl chloride resin molded article may be, for example, a vinyl chloride resin molded article manufactured or used as a pipe (a vinyl chloride resin pipe such as a rigid vinyl chloride resin pipe), or may be a vinyl chloride resin molded article manufactured or used as a vinyl chloride resin product. Examples of the vinyl chloride resin product include vinyl chloride resin manholes such as rigid vinyl chloride resin manholes, vinyl chloride resin gutters, vinyl chloride resin sashes, and vinyl chloride resin boards.

[0042] The pulverized vinyl chloride resin molded body can be obtained through a pulverization step in which a vinyl chloride resin molded body is pulverized to obtain the pulverized vinyl chloride resin molded body. The method for pulverizing the vinyl chloride resin molded body is not particularly limited. Examples of the method for pulverizing the vinyl chloride resin molded body include a method in which the vinyl chloride resin molded body is pulverized using a pulverizer (for example, "ZA-5070" manufactured by Horai Co., Ltd.).

[0043] The shape of the pulverized vinyl chloride resin molded product is not particularly limited. The pulverized vinyl chloride resin molded product may be granular. The pulverized vinyl chloride resin molded product may be pellet-shaped. From the viewpoint of further increasing the affinity with other components such as a heat stabilizer, the pulverized vinyl chloride resin molded product is preferably granular. From the viewpoint of further increasing the heat resistance of the resulting vinyl chloride resin molded product, the pulverized vinyl chloride resin molded product is preferably pellet-shaped. The shape of the pulverized vinyl chloride resin molded product may be spherical, columnar, or flat.

[0044] The size of the pulverized vinyl chloride resin molded product is not particularly limited. The particle size of the pulverized vinyl chloride resin molded product is preferably 0.3 mm or more, more preferably 1.0 mm or more, even more preferably 2.0 mm or more, and preferably 15 mm or less, more preferably 10 mm or less, even more preferably 5.0 mm or less. When the particle size of the pulverized vinyl chloride resin molded product is equal to or greater than the above lower limit and equal to or less than the above upper limit, the heat resistance of the obtained vinyl chloride resin molded product can be further improved, and the mechanical strength of the obtained vinyl chloride resin molded product can be further improved.

[0045] When the pulverized vinyl chloride resin molded product is in granular form, the particle size of the pulverized granular vinyl chloride resin molded product is about 1.0 mm or more and 10 mm or less.When the pulverized vinyl chloride resin molded product is in pellet form, the particle size of the pulverized vinyl chloride resin molded product is about 2.0 mm or more and 5.0 mm or less.

[0046] The particle size of the pulverized vinyl chloride resin molded article is preferably a volume-average particle size. The volume-average particle size is an average diameter 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.

[0047] The pulverized vinyl chloride resin molded product contains a vinyl chloride resin. The vinyl chloride resin in the pulverized vinyl chloride resin molded product (hereinafter, sometimes referred to as vinyl chloride resin A) may be a conventionally known vinyl chloride resin. Examples of the vinyl chloride resin A 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 A may be used alone or in combination of two or more.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The average degree of polymerization of the vinyl chloride resin A is preferably 300 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 A is at least the above-mentioned lower limit, the mechanical strength and impact resistance of the resulting vinyl chloride resin molded article can be further 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 A is at most the above-mentioned upper limit, the heat resistance of the resulting vinyl chloride resin molded article can be further increased, and processability can be further improved.

[0052] The average degree of polymerization of the vinyl chloride resin A can be measured, for example, as follows. The pulverized vinyl chloride resin molded product 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 defined as the average degree of polymerization of the vinyl chloride resin A.

[0053] 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.

[0054] The pulverized vinyl chloride resin molded product may or may not contain a chlorinated vinyl chloride resin. The vinyl chloride resin A may be a chlorinated vinyl chloride resin or a non-chlorinated vinyl chloride resin.

[0055] The material for the vinyl chloride resin molded body and the pulverized vinyl chloride resin molded body may contain components other than the vinyl chloride resin A. The components other than the vinyl chloride resin A are not particularly limited. Examples of the components other than the vinyl chloride resin A include heat stabilizers, heat stabilization aids, antioxidants, lubricants, processing aids, impact modifiers, heat resistance improvers, UV absorbers, antistatic agents, light stabilizers, fillers, colorants, and plasticizers. The components other than the vinyl chloride resin A may be used alone or in combination of two or more.

[0056] The material for the vinyl chloride resin molded body and the pulverized vinyl chloride resin molded body may contain a heat stabilizer. The material for the vinyl chloride resin molded body and the pulverized vinyl chloride resin molded body may contain a lead-based heat stabilizer, an organic acid metal salt-based heat stabilizer, or a tin-based heat stabilizer.

[0057] The content of the pulverized vinyl chloride resin molded product in 100% by weight of the vinyl chloride resin composition is preferably 1.0% by weight or more, more preferably 5.0% by weight or more, even more preferably 10% by weight or more, particularly preferably 20% by weight or more, and is preferably 99.9% by weight or less, more preferably 99% by weight or less, even more preferably 95% by weight or less, particularly preferably 90% by weight or less. When the content of the pulverized vinyl chloride resin molded product is above the lower limit, resource circulation can be further improved and the environmental load can be further reduced. When the content of the pulverized vinyl chloride resin molded product is below the upper limit, processability can be further improved.

[0058] The content of the vinyl chloride resin A in 100% by weight of the pulverized vinyl chloride resin molded product is preferably 50% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, particularly preferably 90% by weight or more, and is preferably 100% by weight or less, more preferably 99.9% by weight or less, even more preferably 99% by weight or less, particularly preferably 98% by weight or less, and most preferably 97% by weight or less. When the content of the vinyl chloride resin A is above the lower limit, resource circulation can be further improved and the environmental load can be further reduced. When the content of the vinyl chloride resin A is below the upper limit, processability can be further improved.

[0059] <Dicarboxylic acid salt> The vinyl chloride resin composition contains a dicarboxylate. In the vinyl chloride resin composition according to the present invention, the dicarboxylate acts as a heat stabilizer. Specifically, the dicarboxylate captures hydrogen chloride generated during decomposition of the vinyl chloride resin, thereby suppressing the generation of bubbles due to the hydrogen chloride, improving the thermal stability of the vinyl chloride resin composition during molding, and increasing the heat resistance of the resulting vinyl chloride resin molded article.

[0060] Examples of the dicarboxylate include alkali metal dicarboxylates and alkaline earth metal dicarboxylates. The dicarboxylate is preferably a salt of a dicarboxylic acid with an alkali metal or a salt of a dicarboxylic acid with an alkaline earth metal. The alkaline earth metals refer to six metals: Be, Mg, Ca, Sr, Ba, and Ra.

[0061] The dicarboxylate salt is preferably a metal salt containing at least one metal selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba.

[0062] From the viewpoint of further enhancing the heat resistance of the vinyl chloride resin molded article to be obtained, the dicarboxylate is preferably an alkali metal dicarboxylate or an alkaline earth metal dicarboxylate, more preferably an alkali metal dicarboxylate, and even more preferably a sodium dicarboxylate.

[0063] Examples of the dicarboxylates include oxalate, malonate, succinate, glutarate, adipate, pimelate, suberate, azelaate, sebacate, fumarate, and maleate. Examples of dicarboxylic acids constituting the dicarboxylates include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, and maleic acid. Only one type of the dicarboxylates may be used, or two or more types may be used in combination.

[0064] From the viewpoint of further improving the heat resistance of the resulting vinyl chloride resin molded article, the carbon number of the dicarboxylate is preferably 2 or more, more preferably 4 or more, even more preferably 6 or more, and preferably 22 or less, more preferably 16 or less, even more preferably 12 or less. The carbon number of the dicarboxylate includes the number of carbon atoms in the portion derived from the carboxy group of the dicarboxylic acid.

[0065] From the viewpoint of further improving the heat resistance of the vinyl chloride resin molded article to be obtained, the dicarboxylate is preferably an adipate, and more preferably disodium adipate.

[0066] The content of the dicarboxylate salt in 100% by weight of the vinyl chloride resin composition is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, even more preferably 0.5% by weight or more, particularly preferably 0.7% by weight or more, and most preferably 1.0% by weight or more, and is preferably 5.0% by weight or less, more preferably 3.0% by weight or less, even more preferably 2.5% by weight or less, and particularly preferably 2.0% by weight or less. When the content of the dicarboxylate salt is at least the above-mentioned lower limit, the heat resistance of the resulting vinyl chloride resin molded article can be further improved, and the occurrence of fading and discoloration of the molded article can be more effectively suppressed. When the content of the dicarboxylate salt is at most the above-mentioned upper limit, the impact resistance of the resulting vinyl chloride resin molded article can be further improved.

[0067] The content of the dicarboxylate salt is preferably 0.5 parts by weight or more, more preferably 1.0 parts by weight or more, even more preferably 2.0 parts by weight or more, and particularly preferably 3.0 parts by weight or more, relative to 100 parts by weight of the pulverized vinyl chloride resin molded product, and is preferably 100 parts by weight or less, more preferably 50 parts by weight or less, even more preferably 10 parts by weight or less, and particularly preferably 5.0 parts by weight or less. When the content of the dicarboxylate salt is at least the above-mentioned lower limit, the heat resistance of the resulting vinyl chloride resin molded product can be further improved, and the occurrence of fading and discoloration of the molded product can be more effectively suppressed. When the content of the dicarboxylate salt is at most the above-mentioned upper limit, the impact resistance of the resulting vinyl chloride resin molded product can be further improved.

[0068] The content of the dicarboxylate salt is preferably 0.1 parts by weight or more, more preferably 0.3 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 most preferably 1.0 parts by weight or more, relative to 100 parts by weight of the total content of all components in the vinyl chloride resin composition excluding the dicarboxylate salt, and is preferably 5.0 parts by weight or less, more preferably 3.0 parts by weight or less, even more preferably 2.5 parts by weight or less, and particularly preferably 2.0 parts by weight or less. When the content of the dicarboxylate salt is at least the above-mentioned lower limit, the heat resistance of the resulting vinyl chloride resin molded article can be further improved, and the occurrence of fading and discoloration of the molded article can be more effectively suppressed. When the content of the dicarboxylate salt is at most the above-mentioned upper limit, the impact resistance of the resulting vinyl chloride resin molded article can be further improved.

[0069] <Vinyl chloride resin> The vinyl chloride resin composition may or may not further contain a vinyl chloride resin (hereinafter, sometimes referred to as vinyl chloride resin B). From the viewpoint of further increasing the impact resistance of the resulting vinyl chloride resin molded article, it is preferable that the vinyl chloride resin composition further contains a vinyl chloride resin. From the viewpoint of further increasing the impact resistance of the resulting vinyl chloride resin molded article, it is preferable that the vinyl chloride resin composition contains a pulverized vinyl chloride resin molded article, a dicarboxylic acid salt, and a vinyl chloride resin. It is preferable that the vinyl chloride resin is a new material that has never been used to obtain a product. The new material that has never been used to obtain a product includes a new material that has never been used as a product.

[0070] Examples of the vinyl chloride resin B include the vinyl chloride resins described above. The vinyl chloride resin B may be the same as or different from the vinyl chloride resin (vinyl chloride resin A) in the pulverized vinyl chloride resin molded product.

[0071] The vinyl chloride resin B may or may not be a rigid vinyl chloride resin. From the viewpoint of further increasing the mechanical strength and impact resistance of the resulting vinyl chloride resin molded article, the vinyl chloride resin B is preferably a rigid vinyl chloride resin.

[0072] The average degree of polymerization of the vinyl chloride resin B is preferably 500 or more, more preferably 600 or more, even more preferably 800 or more, and preferably 3000 or less, more preferably 2000 or less, even more preferably 1500 or less, and particularly preferably 1400 or less. When the average degree of polymerization of the vinyl chloride resin B is at least the above-mentioned lower limit, the mechanical strength and impact resistance of the resulting vinyl chloride resin molded article can be further 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 B is at most the above-mentioned upper limit, the heat resistance of the resulting vinyl chloride resin molded article can be further increased, and processability can be further improved.

[0073] The average degree of polymerization of the vinyl chloride resin B can be measured, for example, as follows. The vinyl chloride resin B 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 B.

[0074] When the vinyl chloride resin composition contains the vinyl chloride resin B, the content of the vinyl chloride resin B in 100% by weight of the vinyl chloride resin composition is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 40% by weight or more, and preferably 99% by weight or less, more preferably 90% by weight or less, even more preferably 80% by weight or less, and particularly preferably 70% by weight or less. When the content of the vinyl chloride resin B is above the lower limit, the heat resistance, processability, mechanical strength, and impact resistance of the resulting vinyl chloride resin molded article can be further improved, and long-term performance such as fatigue properties can be made less likely to be impaired. When the content of the vinyl chloride resin B is below the upper limit, resource circulation can be further improved and the environmental load can be further reduced.

[0075] When the vinyl chloride resin composition contains the vinyl chloride resin B, the content of the vinyl chloride resin B is preferably 50 parts by weight or more, more preferably 70 parts by weight or more, even more preferably 100 parts by weight or more, and preferably 900 parts by weight or less, more preferably 500 parts by weight or less, even more preferably 300 parts by weight or less, particularly preferably 250 parts by weight or less, and most preferably 200 parts by weight or less, per 100 parts by weight of the pulverized vinyl chloride resin molded article. When the content of the vinyl chloride resin B is above the lower limit, the heat resistance, processability, mechanical strength, and impact resistance of the resulting vinyl chloride resin molded article can be further improved, and long-term performance such as fatigue properties can be less likely to be impaired. When the content of the vinyl chloride resin B is below the upper limit, resource circulation can be further improved, and the environmental impact can be further reduced.

[0076] When the vinyl chloride resin composition contains the vinyl chloride resin B, the total content of the pulverized vinyl chloride resin molded product and the vinyl chloride resin B, based on 100% by weight of the vinyl chloride resin composition, is preferably 50% by weight or more, more preferably 60% by weight or more, even more preferably 70% by weight or more, and preferably 99.9% by weight or less, more preferably 99% by weight or less, even more preferably 97% by weight or less. When the total content of the pulverized vinyl chloride resin molded product and the vinyl chloride resin B is above the lower limit, the mechanical strength and impact resistance of the resulting vinyl chloride resin molded product can be further increased, and long-term performance such as fatigue properties can be made less likely to be impaired. When the total content of the pulverized vinyl chloride resin molded product and the vinyl chloride resin B is below the upper limit, the heat resistance of the resulting vinyl chloride resin molded product can be further increased, and processability can be further improved.

[0077] <Other ingredients> The vinyl chloride resin composition may contain additives as needed. Examples of the additives include heat stabilizers other than dicarboxylates, 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.

[0078] The vinyl chloride resin composition may or may not contain a heat stabilizer other than the dicarboxylate. Examples of the heat stabilizer other than the dicarboxylate include a tin-based heat stabilizer, a lead-based heat stabilizer, a calcium-zinc-based heat stabilizer, and a barium-zinc-based heat stabilizer. The heat stabilizer other than the dicarboxylate may be used alone or in combination of two or more.

[0079] 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.

[0080] Examples of the lead-based heat stabilizer include lead stearate, 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.

[0081] The heat stabilizer other than the dicarboxylate may be an organic acid metal salt-based heat stabilizer, such as calcium stearate, barium stearate, or zinc stearate.

[0082] From the viewpoint of further reducing the toxicity of the vinyl chloride resin composition, it is preferable that the vinyl chloride resin composition does not contain the lead-based heat stabilizer. When the pulverized vinyl chloride resin molded product contains a lead-based heat stabilizer, from the viewpoint of suppressing the occurrence of defective appearance of the resulting vinyl chloride resin molded product, it is preferable that the vinyl chloride resin composition does not contain a tin-based heat stabilizer.

[0083] The content of the heat stabilizer other than the dicarboxylate salt, based on 100% by weight of the vinyl chloride resin composition, is preferably 0.3% by weight or more, more preferably 0.5% by weight or more, even more preferably 1.0% by weight or more, and preferably 5.0% by weight or less, more preferably 3.0% by weight or less, and even more preferably 2.0% by weight or less. When the content of the heat stabilizer other than the dicarboxylate salt 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 occurrence of fading and discoloration of the molded article can be more effectively suppressed. When the content of the heat stabilizer other than the dicarboxylate salt is equal to or less than the upper limit, the impact resistance of the resulting vinyl chloride resin molded article can be further improved.

[0084] 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.

[0085] 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.

[0086] 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, epoxy 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] Examples of the filler include calcium carbonate, talc, etc. The filler may be used alone or in combination of two or more.

[0093] 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.

[0094] (Method of producing vinyl chloride resin composition) The method for producing a vinyl chloride resin composition according to the present invention includes a mixing step of mixing a pulverized vinyl chloride resin molded product with a dicarboxylate. This method is for producing a vinyl chloride resin composition containing the pulverized vinyl chloride resin molded product and the dicarboxylate (optionally with a vinyl chloride resin and optionally with other components).

[0095] The method for producing a vinyl chloride resin composition according to the present invention has the above-mentioned features, and therefore, in a vinyl chloride resin molded article obtained using the vinyl chloride resin composition, it is possible to suppress the occurrence of defective appearance, improve heat resistance, and improve impact resistance.

[0096] From the viewpoint of further improving the impact resistance of the resulting vinyl chloride resin molded article, it is preferable that the vinyl chloride resin composition further contains a vinyl chloride resin. Therefore, it is preferable that the mixing step is a step of mixing a pulverized product of the vinyl chloride resin molded article, the dicarboxylate, and a vinyl chloride resin. In this case, the method for producing the vinyl chloride resin composition is a mixing step of mixing a pulverized product of the vinyl chloride resin molded article, the dicarboxylate, and a vinyl chloride resin. This method for producing a vinyl chloride resin composition is a method for producing a vinyl chloride resin composition containing the pulverized product of the vinyl chloride resin molded article, the dicarboxylate, and the vinyl chloride resin.

[0097] The mixing step preferably includes a first mixing step of mixing the pulverized vinyl chloride resin molded product with the dicarboxylate, and a second mixing step of mixing the vinyl chloride resin with the mixture of the pulverized vinyl chloride resin molded product and the dicarboxylate. That is, the mixing step is preferably a multi-stage mixing step in which the three specific components are mixed in multiple stages rather than all at once in a single stage. The method for producing a vinyl chloride resin composition is a method for producing a vinyl chloride resin composition containing a pulverized vinyl chloride resin molded product, a dicarboxylate, and a vinyl chloride resin (optionally with other components).

[0098] By carrying out the multi-stage mixing process including the first and second mixing processes, the toxicity of the vinyl chloride resin composition can be more effectively reduced, and the occurrence of defective appearance can be more effectively suppressed, the heat resistance can be more effectively improved, and the impact resistance can be more effectively improved in a vinyl chloride resin molded article obtained using the vinyl chloride resin composition.

[0099] The method for mixing the pulverized vinyl chloride resin molded product with the dicarboxylate is not particularly limited. Furthermore, the method for mixing the pulverized vinyl chloride resin molded product with the dicarboxylate and the vinyl chloride resin is not particularly limited. Furthermore, the method for mixing the vinyl chloride resin with the mixture of the pulverized vinyl chloride resin molded product and the dicarboxylate is not particularly limited. The materials may be mixed using a mixer (for example, a "ribbon blender" manufactured by Nippon Color Industries Co., Ltd.).

[0100] In the method for producing a vinyl chloride resin composition according to the present invention, a pulverized vinyl chloride resin molded article that has been previously obtained or prepared may be used. Since this increases the recycling efficiency, the method for producing a vinyl chloride resin composition according to the present invention preferably includes a pulverization step of pulverizing a vinyl chloride resin molded article to obtain the pulverized vinyl chloride resin molded article.

[0101] (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 described above. The vinyl chloride resin molded article is obtained by molding the vinyl chloride resin composition described above. The vinyl chloride resin molded article according to the present invention is a recycled vinyl chloride resin molded article (recycled product).

[0102] The vinyl chloride resin molded article according to the present invention has the above-described configuration, and therefore can improve heat resistance, suppress the occurrence of defective appearance, and improve impact resistance.

[0103] 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, and more preferably as a rigid vinyl chloride resin pipe. The vinyl chloride resin molded article may be a molded article other than a vinyl chloride resin pipe.

[0104] 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, and press molding.

[0105] Examples of molding machines used for molding include single-screw extruders, twin-screw counter-rotating parallel extruders, twin-screw counter-rotating conical extruders, twin-screw co-rotating extruders, etc. The heating temperature when molding using the above molding machines is preferably 140°C or higher and preferably 190°C or lower.

[0106] From the viewpoints of improving the heat resistance of the vinyl chloride resin molded article, suppressing the occurrence of defective appearance, and improving impact resistance, the molded article of the vinyl chloride resin composition (vinyl chloride resin molded article) is preferably an extrusion molded article of the vinyl chloride resin composition described above. That is, the molded article (vinyl chloride resin molded article) is preferably an extrusion molded article.

[0107] (Vinyl chloride resin pipe) The vinyl chloride resin pipe of the present invention is a single-layer pipe having a single layer structure or a multi-layer pipe having a laminated structure of two or more layers. In the vinyl chloride resin pipe of the present invention, one layer of the single-layer pipe or at least one layer of the multi-layer pipe is a molded article of the vinyl chloride resin composition described above (vinyl chloride resin molded article).

[0108] The vinyl chloride resin pipe according to the present invention has the above-mentioned configuration, and therefore can improve heat resistance, suppress the occurrence of poor appearance, and improve impact resistance.

[0109] FIG. 1 is a cross-sectional view schematically showing a vinyl chloride resin pipe according to a first embodiment of the present invention.

[0110] The vinyl chloride resin pipe 11 includes a first layer 1. The first layer 1 is tubular. The vinyl chloride resin pipe 11 is a single-layer pipe including only the first layer 1. The first layer 1 is a molded article of the vinyl chloride resin composition described above.

[0111] The vinyl chloride resin pipe is preferably a single-layer pipe having a one-layer structure, and one layer of the single-layer pipe is preferably a molded article of the vinyl chloride resin composition. When the vinyl chloride resin pipe according to the present invention is a single-layer pipe, the single-layer pipe is a molded article of the vinyl chloride resin composition described above.

[0112] FIG. 2 is a cross-sectional view schematically showing a vinyl chloride resin pipe according to a second embodiment of the present invention.

[0113] The vinyl chloride resin pipe 11A comprises a first layer 1A, a second layer 2A, and a third layer 3A. The second layer 2A is laminated on the inner surface of the first layer 1A. The third layer 3A is laminated on the inner surface of the second layer 2A. The first layer 1A, the second layer 2A, and the third layer 3A are each tubular. The first layer 1A is the outermost layer, the second layer 2A is the middle layer, and the third layer 3A is the innermost layer. The first layer 1A, the second layer 2A, and the third layer 3A each extend to both ends of the vinyl chloride resin pipe 11A. The vinyl chloride resin pipe 11A is a multi-layer pipe having a three-layer structure. At least one of the first layer 1A, the second layer 2A, and the third layer 3A is a molded article made of the vinyl chloride resin composition.

[0114] It is also preferable that the vinyl chloride resin pipe is a multi-layer pipe having a laminated structure of two or more layers, at least one layer of which is a molded article of the vinyl chloride resin composition. When the vinyl chloride resin pipe according to the present invention is a multi-layer pipe, the multi-layer pipe has one or more layers which are molded articles of the vinyl chloride resin composition.

[0115] The multi-layer pipe preferably includes an inner layer and an outer layer disposed on the outer surface of the inner layer. In the multi-layer pipe, the outer layer is preferably laminated on the outer surface of the inner layer.

[0116] The multilayer pipe may have a laminated structure of two layers, a laminated structure of three layers, a laminated structure of three or more layers, a laminated structure of ten or fewer layers, or a laminated structure of five or fewer layers.

[0117] The multi-layer pipe may include an intermediate layer. The multi-layer pipe may have an intermediate layer between the inner layer and the outer layer. The multi-layer pipe preferably includes the inner layer, an intermediate layer disposed on the outer surface of the inner layer, and an outer layer disposed on the outer surface of the intermediate layer. The inner layer is a layer located inside the intermediate layer. The outer layer is a layer located outside the intermediate layer. The multi-layer pipe preferably includes the inner layer, intermediate layer, and outer layer in this order from the center to the outside.

[0118] The inner layer may be a single layer or multiple layers. The inner layer may be a single layer, two layers, two or more layers, or three or more layers. The intermediate layer may be a single layer or multiple layers. The intermediate layer may be a single layer, two layers, two or more layers, or three or more layers. The outer layer may be a single layer or multiple layers. The outer layer may be a single layer, two layers, two or more layers, or three or more layers.

[0119] In the multi-layer pipe, the inner layer may be a molded article of the vinyl chloride resin composition, the outer layer may be a molded article of the vinyl chloride resin composition, and the intermediate layer may be a molded article of the vinyl chloride resin composition. In the multi-layer pipe, the inner layer and the intermediate layer may be molded articles of the vinyl chloride resin composition, the inner layer and the outer layer may be molded articles of the vinyl chloride resin composition, or the intermediate layer and the outer layer may be molded articles of the vinyl chloride resin composition. In the multi-layer pipe, the inner layer, the intermediate layer, and the outer layer may be molded articles of the vinyl chloride resin composition. The layer that is a molded article of the vinyl chloride resin composition may be the inner layer, the intermediate layer, or the outer layer.

[0120] 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.

[0121] From the viewpoint of improving processability, the thickness of the layer that is the molded product of the vinyl chloride resin composition is preferably 0.3 mm or more, more preferably 0.5 mm or more, even more preferably 1.0 mm or more, and is preferably 15 mm or less, more preferably 10 mm or less, even more preferably 7.0 mm or less.

[0122] The configuration of the layers other than the layer that is a molded product of the vinyl chloride resin composition is not particularly limited, and the material of the layers other than the layer that is a molded product of the vinyl chloride resin composition may or may not contain a vinyl chloride resin.

[0123] 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.

[0124] The following materials were prepared:

[0125] Crushed polyvinyl chloride resin moldings: Used polyvinyl chloride resin pipes (collected from the community) were crushed in a crusher (HORAI Co., Ltd. "ZA-5070") to obtain crushed material (granular, particle size (volume average particle size): 6 mm).

[0126] Dicarboxylates: Disodium adipate Disodium succinate

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

[0128] Other Ingredients: Lubricant (ester wax, Riken Vitamin Co., Ltd. "Rikemar EW-250") Lubricant (polyethylene wax, Mitsui Chemicals "Hiwax 4202E") Colorant (gray pigment) Filler (calcium carbonate, Toyo Fine Chemical Co., Ltd. "Whiten 305") Heat stabilizer (lead-based heat stabilizer (lead stearate), Sakai Chemical Industry Co., Ltd. "SL-1000") Heat stabilizer (tin-based heat stabilizer (di-n-octyltin-S,S'-bis(2-ethylhexylmercaptoacetate)), "TVS#8832" manufactured by Nitto Kasei Co., Ltd.) Heat stabilizer (organic acid metal salt heat stabilizer (calcium stearate), Sakai Chemical Industry Co., Ltd. "SC-100")

[0129] Example 1 Preparation of vinyl chloride resin composition: The following materials were blended and stirred using a Henschel mixer while heating to 80°C to obtain a mixture (first mixing step): 66.4 parts by weight of vinyl chloride resin, 0.2 parts by weight of lubricant (ester wax), 0.2 parts by weight of lubricant (polyethylene wax), 0.2 parts by weight of colorant, 2.0 parts by weight of filler, and 1.0 part by weight of heat stabilizer (lead-based heat stabilizer).

[0130] The obtained mixture, 30 parts by weight of pulverized vinyl chloride resin molded body, and 1.0 part by weight of disodium adipate were placed in a blender and mixed by stirring for 10 minutes to obtain a vinyl chloride resin composition (second mixing step).

[0131] Preparation of PVC tubes: The obtained vinyl chloride resin composition was extrusion molded under the following conditions using a twin-screw parallel extruder ("SLM-90" manufactured by Nagata Seisakusho) to obtain a vinyl chloride resin molded product (a vinyl chloride resin pipe with a nominal diameter of VP50 and a thickness of 4.5 mm).

[0132] Molding temperature: Cylinder supply side 160℃, cylinder center 165℃, cylinder discharge side 170℃, mold 180℃ Screw rotation speed: 30 rpm Extrusion rate: 200 kg / hr

[0133] (Examples 2 to 6 and Comparative Examples 1 to 4) Vinyl chloride resin compositions and vinyl chloride resin molded articles 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.

[0134] In Example 5, which did not use a vinyl chloride resin, a single-stage mixing process in which all components were mixed in one stage was carried out instead of the multi-stage mixing process including the first and second mixing processes.

[0135] (1) Poor appearance of vinyl chloride resin molded products The vinyl chloride resin molded articles obtained were visually inspected for appearance defects such as discoloration and discoloration, etc. The appearance defects of the vinyl chloride resin molded articles were judged according to the following criteria.

[0136] [Criteria for determining appearance defects in vinyl chloride resin molded products] ○: No appearance defects ×: Poor appearance

[0137] (2) Heat resistance of vinyl chloride resin molded products A 30 mm x 30 mm test piece was cut from the obtained vinyl chloride resin molded article and placed in a Geer oven heated to 180°C. The test piece was then removed every 10 minutes and the time it took for the test piece to start to turn brown was measured. The heat resistance of the vinyl chloride resin molded article was evaluated according to the following criteria.

[0138] [Criteria for determining heat resistance of vinyl chloride resin molded products] 〇〇: Discoloration begins after 70 minutes or more ○: Discoloration begins after 60 minutes ×: Discoloration begins in 50 minutes or less

[0139] (3) Impact resistance of vinyl chloride resin molded products The vinyl chloride resin molded articles were cut into lengths of 150 mm ± 5 mm according to JIS K 6741 (Appendix JA) to obtain five test specimens. After allowing the test specimens to stand at 0°C ± 3°C for 60 minutes, a 3 kg cylindrical flat-bottomed weight was dropped onto the specimens from a height of 100 cm, and the five specimens were checked for cracks. The impact resistance of the vinyl chloride resin molded articles was evaluated according to the following criteria. If none of the five specimens in the first test were crack-free, they were judged as "Good: Resistant to cracks and cracks." If two or more of the five specimens in the first test were crack-free, they were judged as "Poor: Resistant to cracks and cracks." If one of the five specimens in the first test was crack-free, the same test was conducted again (a second time) on the remaining five specimens. If none of the five specimens in the second test were crack-free, they were judged as "Good: Resistant to cracks and cracks." If one or more of the five test specimens in the second test had a crack or fissure, the specimen was judged as "x: prone to crack or fissure."

[0140] [Criteria for determining impact resistance of vinyl chloride resin molded products] 〇: Less likely to crack or break ×: Breaks and cracks are likely to occur

[0141] The compositions of the vinyl chloride resin compositions and the results are shown in Tables 1 and 2.

[0142] [Table 1]

[0143] [Table 2] [Explanation of symbols]

[0144] 1,1A...first layer 2A...Second layer 3A...Third layer 11, 11A...Vinyl chloride resin pipe

Claims

1. A vinyl chloride resin composition comprising a pulverized vinyl chloride resin molded article and a dicarboxylic acid salt.

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

3. 3. The vinyl chloride resin composition according to claim 1, wherein the content of the dicarboxylate is 0.1 parts by weight or more and 5.0 parts by weight or less, based on 100 parts by weight of the total content of components excluding the dicarboxylate in the vinyl chloride resin composition.

4. 3. The vinyl chloride resin composition according to claim 1, wherein the dicarboxylate has 2 or more and 22 or less carbon atoms.

5. 3. The vinyl chloride resin composition according to claim 1, wherein the dicarboxylate is an alkali metal dicarboxylate or an alkaline earth metal dicarboxylate.

6. 3. The vinyl chloride resin composition according to claim 1, wherein the dicarboxylate is a sodium dicarboxylate.

7. 3. The vinyl chloride resin composition according to claim 1, wherein the dicarboxylate is disodium adipate.

8. A method for producing a vinyl chloride resin composition, comprising a mixing step of mixing a pulverized vinyl chloride resin molded article with a dicarboxylic acid salt.

9. 9. The method for producing a vinyl chloride resin composition according to claim 8, wherein the mixing step is a step of mixing the pulverized vinyl chloride resin molded article, the dicarboxylic acid salt, and a vinyl chloride resin.

10. 10. The method for producing a vinyl chloride resin composition according to claim 9, wherein the mixing step comprises: a first mixing step of mixing the pulverized vinyl chloride resin molded product with the dicarboxylate; and a second mixing step of mixing the vinyl chloride resin with the mixture of the pulverized vinyl chloride resin molded product and the dicarboxylate.

11. The method for producing a vinyl chloride resin composition according to any one of claims 8 to 10, further comprising a pulverization step of pulverizing a vinyl chloride resin molded body to obtain a pulverized product of the vinyl chloride resin molded body.

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

13. The vinyl chloride resin molded article according to claim 12, which is an extrusion molded article.

14. It is a single-layer pipe having a single layer structure or a multi-layer pipe having a laminated structure of two or more layers, A vinyl chloride resin pipe, wherein one layer of the single-layer pipe or at least one layer of the multi-layer pipe is a molded article of the vinyl chloride resin composition according to claim 1 or 2.

15. The single-layer pipe has a one-layer structure, 15. The vinyl chloride resin pipe according to claim 14, wherein one layer of the single-layer pipe is a molded article of the vinyl chloride resin composition.

16. The multilayer pipe has a laminated structure of two or more layers, 15. The vinyl chloride resin pipe according to claim 14, wherein at least one layer of the multi-layer pipe is a molded article of the vinyl chloride resin composition.

17. The polyvinyl chloride resin pipe according to claim 14, which is a rigid polyvinyl chloride resin pipe.

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