Method for producing vinyl chloride resin composition

Abstract

The purpose of the present invention is to provide a method for producing a vinyl chloride resin composition capable of forming a molded vinyl chloride resin having excellent low-temperature tensile elongation. This method for producing a vinyl chloride resin composition is characterized by including a kneading step in which a vinyl chloride resin and an additive are kneaded to obtain a kneaded product and a crushing step in which the kneaded product is crushed by a crusher, and is also characterized in that the crusher is configured so that the contents are crushed with rotating blades affixed concentrically to a shaft and fixed blades corresponding to the rotating blades.

Description

Method for producing vinyl chloride resin composition

[0001] The present invention relates to a method for producing a vinyl chloride resin composition.

[0002] Vinyl chloride resins are generally used in a variety of applications due to their excellent properties, such as cold resistance, heat resistance, and oil resistance. Specifically, for example, automotive interior parts such as automotive instrument panels and door trims are formed using automotive interior materials such as skins made of vinyl chloride resin molded articles and laminates made of vinyl chloride resin molded articles backed with foam such as polyurethane foam. Vinyl chloride resin molded articles that constitute the skins of automotive interior parts such as automotive instrument panels are produced, for example, by molding a vinyl chloride resin composition containing vinyl chloride resin, a plasticizer, and additives such as pigments using a known molding method such as powder slush molding.

[0003] In recent years, with the aim of improving the physical properties of such vinyl chloride resin molded articles, studies have been conducted on producing a vinyl chloride resin composition by kneading a vinyl chloride resin with additives such as a plasticizer and then pulverizing the resulting mixture (kneaded product). For example, Patent Document 1 discloses a method for producing a vinyl chloride resin composition, which includes a step of kneading a vinyl chloride resin, a plasticizer, and an inorganic substance to obtain a mixture, and a step of pulverizing the mixture to obtain mixture particles.

[0004] International Publication No. 2022 / 210779

[0005] However, vinyl chloride resin molded articles formed using vinyl chloride resin compositions obtained by the above-mentioned conventional manufacturing methods have room for improvement in tensile elongation when evaluated at low temperatures (hereinafter also referred to as "low-temperature tensile elongation").

[0006] Therefore, an object of the present invention is to provide a method for producing a vinyl chloride resin composition that can form a vinyl chloride resin molded article having excellent low-temperature tensile elongation.

[0007] The present inventors have conducted extensive research with the aim of solving the above problems, and have newly discovered that a vinyl chloride resin composition capable of forming a vinyl chloride resin molded article having excellent low-temperature tensile elongation can be obtained by pulverizing a kneaded mixture of vinyl chloride resin and additives using a pulverizer having a predetermined configuration, thereby completing the present invention.

[0008]

[0010] The present invention aims to advantageously solve the above-mentioned problems, and [1] the present invention is a method for producing a vinyl chloride resin composition, comprising a kneading step of kneading a vinyl chloride resin and an additive to obtain a kneaded mixture, and a pulverizing step of pulverizing the kneaded mixture using a pulverizer, the pulverizer being configured to pulverize the contents with a rotary blade concentrically attached to a shaft and a fixed blade corresponding to the rotary blade. In this way, if a vinyl chloride resin composition is produced by pulverizing a kneaded mixture of a vinyl chloride resin and an additive using a predetermined pulverizer, a vinyl chloride resin molded article having excellent low-temperature tensile elongation can be formed using the vinyl chloride resin composition.

[0009] [2] In the method for producing a vinyl chloride resin composition according to [1] above, it is preferable that the clearance between the rotary blade and the fixed blade is 0.01 mm or more and 2.0 mm or less. As described above, when the clearance between the rotary blade and the fixed blade provided in the pulverizer is within the above-mentioned range, a vinyl chloride resin composition capable of forming a vinyl chloride resin molded product having even better low-temperature tensile elongation can be obtained.

[0010] [3] In the method for producing a vinyl chloride resin composition according to [1] or [2] above, the additive preferably contains a plasticizer in a proportion of 40 to 200 parts by mass per 100 parts by mass of the vinyl chloride resin. Thus, when the content of the plasticizer as an additive is equal to or greater than the lower limit, sufficient flexibility can be imparted to a vinyl chloride resin molded article formed using the resulting vinyl chloride resin composition, and the low-temperature tensile elongation of the vinyl chloride resin molded article can be further improved. Furthermore, when the content of the plasticizer as an additive is equal to or less than the upper limit, the kneaded product of the vinyl chloride resin and the additive can be pulverized well, and the low-temperature tensile elongation of the vinyl chloride resin molded article can be further improved.

[0011] [4] In the method for producing a vinyl chloride resin composition according to any one of the above [1] to [3], the kneading step preferably includes a step of pelletizing the kneaded mixture. By forming the kneaded mixture of vinyl chloride resin into pellets in this way, the kneaded mixture can be easily pulverized with a pulverizer to obtain the vinyl chloride resin composition.

[0012] [5] In the method for producing a vinyl chloride resin composition according to any one of the above [1] to [4], the aspect ratio b / l of the vinyl chloride resin composition is ３ In this way, the aspect ratio b / l of the vinyl chloride resin composition produced is preferably 0.550 or more and less than 0.698. ３ In the present invention, when the aspect ratio b / l of the vinyl chloride resin composition is within the above-mentioned range, the vinyl chloride resin composition has excellent powder flowability. ３ can be determined by the method described in the Examples.

[0013] According to the present invention, there is provided a method for producing a vinyl chloride resin composition that can form a vinyl chloride resin molded article having excellent low-temperature tensile elongation.

[0014] 1 is a front view of an example of a crusher used in the present invention; FIG. 2 is a side view of the crusher of FIG. 1; FIG. 3 is a plan sectional view of the crusher of FIG. 1; and FIG. 4 is a side sectional view of the crusher of FIG.

[0015] Hereinafter, embodiments of the present invention will be described in detail. The method for producing a vinyl chloride resin composition of the present invention can be used to produce a vinyl chloride resin composition. The vinyl chloride resin composition produced by the method for producing a vinyl chloride resin composition of the present invention can be used, for example, to form a vinyl chloride resin molded article. The vinyl chloride resin molded article can be suitably used, for example, as an automotive interior material such as the skin of an automotive interior part, such as an automotive instrument panel or door trim.

[0016] (Method for Producing Vinyl Chloride Resin Composition) The method for producing a vinyl chloride resin composition of the present invention comprises a kneading step of kneading a vinyl chloride resin and an additive to obtain a kneaded mixture, and a pulverizing step of pulverizing the kneaded mixture using a pulverizer, wherein the pulverizer is configured to pulverize the contents using a rotary blade concentrically attached to a shaft and a fixed blade corresponding to the rotary blade. According to the method for producing a vinyl chloride resin composition of the present invention, a vinyl chloride resin composition capable of forming a vinyl chloride resin molded article having excellent low-temperature tensile elongation can be produced.

[0017] <Kneading Step> In the kneading step, a vinyl chloride resin and additives are kneaded to obtain a kneaded mixture. By kneading the vinyl chloride resin and additives, it is possible to improve the low-temperature tensile elongation of a vinyl chloride resin molded article formed using the obtained vinyl chloride resin composition.

[0018] <<Vinyl Chloride Resin>> As the vinyl chloride resin, a particulate vinyl chloride resin is usually used. The vinyl chloride resin may contain, for example, one or more types of vinyl chloride resin particles, and may optionally further contain one or more types of vinyl chloride resin microparticles. Among these, the vinyl chloride resin preferably contains at least vinyl chloride resin particles, and more preferably contains vinyl chloride resin particles and vinyl chloride resin microparticles. The vinyl chloride resin may be produced by any conventionally known production method, such as suspension polymerization, emulsion polymerization, solution polymerization, or bulk polymerization. In the present invention, "resin particles" refers to particles having a particle diameter of 30 μm or more, and "resin microparticles" refers to particles having a particle diameter of less than 30 μm.

[0019] Examples of vinyl chloride resins include homopolymers composed of vinyl chloride monomer units, as well as vinyl chloride copolymers containing preferably 50% by mass or more, more preferably 70% by mass or more, of vinyl chloride monomer units. Specific examples of monomers (comonomers) copolymerizable with vinyl chloride monomers that can constitute vinyl chloride copolymers include those described in International Publication No. WO 2016 / 098344. These components may be used alone or in combination of two or more in any ratio.

[0020] [Vinyl chloride resin particles] Vinyl chloride resin particles usually function as a matrix resin (substrate) in the resulting vinyl chloride resin composition. The vinyl chloride resin particles are preferably produced by suspension polymerization.

[0021] -Average Degree of Polymerization- The average degree of polymerization of the vinyl chloride resin constituting the vinyl chloride resin particles is preferably 800 or more, more preferably 1000 or more, even more preferably 1300 or more, and preferably 5000 or less, more preferably 3000 or less, even more preferably 2800 or less, particularly preferably 2300 or less, and even more preferably 1900 or less. If the average degree of polymerization of the vinyl chloride resin constituting the vinyl chloride resin particles is equal to or greater than the above-mentioned lower limit, the physical strength of the vinyl chloride resin molded article formed using the resulting vinyl chloride resin composition can be sufficiently ensured, while, for example, the tensile properties, particularly the tensile elongation, can be improved. Furthermore, if the average degree of polymerization of the vinyl chloride resin constituting the vinyl chloride resin particles is equal to or less than the above-mentioned upper limit, the meltability of the resulting vinyl chloride resin composition can be improved. In the present invention, the "average degree of polymerization" of the vinyl chloride resin can be measured in accordance with JIS K6720-2.

[0022] -Volume average particle diameter- The volume average particle diameter of the vinyl chloride resin particles is typically 30 μm or more, preferably 50 μm or more, more preferably 100 μm or more, and preferably 500 μm or less, more preferably 200 μm or less. When the volume average particle diameter of the vinyl chloride resin particles is within the above-mentioned range, the vinyl chloride resin can be well mixed in the kneaded product prepared, thereby further improving the low-temperature tensile elongation of a vinyl chloride resin molded article formed using a vinyl chloride resin composition produced by pulverizing the kneaded product. In the present invention, the "volume average particle diameter of the vinyl chloride resin particles" can be measured by laser diffraction in accordance with JIS Z8825.

[0023] -Content- The content of vinyl chloride resin particles in the vinyl chloride resin is preferably 70% by mass or more, more preferably 80% by mass or more, and can be 100% by mass, and is preferably 95% by mass or less, and more preferably 90% by mass or less. When the content of vinyl chloride resin particles in the vinyl chloride resin is equal to or greater than the above-mentioned lower limit, the vinyl chloride resin molded article formed using the obtained vinyl chloride resin composition can have good tensile elongation while ensuring sufficient physical strength. Furthermore, when the content of vinyl chloride resin particles in the vinyl chloride resin is equal to or less than the above-mentioned upper limit, the powder flowability of the obtained vinyl chloride resin composition is improved.

[0024] <<Vinyl chloride resin fine particles>> Vinyl chloride resin fine particles usually function as a dusting agent (powder flow improver) in the resulting vinyl chloride resin composition. The vinyl chloride resin fine particles are preferably produced by emulsion polymerization.

[0025] -Average Degree of Polymerization- The average degree of polymerization of the vinyl chloride resin constituting the vinyl chloride resin microparticles is preferably 500 or more, more preferably 700 or more, and preferably 2600 or less, more preferably 2400 or less. When the average degree of polymerization of the vinyl chloride resin constituting the vinyl chloride resin microparticles as a dusting agent is equal to or greater than the above-mentioned lower limit, the powder fluidity of the resulting vinyl chloride resin composition is improved, and the tensile elongation of a molded article obtained using the composition is improved. Furthermore, when the average degree of polymerization of the vinyl chloride resin constituting the vinyl chloride resin microparticles is equal to or less than the above-mentioned upper limit, the meltability of the resulting vinyl chloride resin composition is improved, and the surface smoothness of a vinyl chloride resin molded article formed using the composition is improved.

[0026] -Volume average particle diameter- The volume average particle diameter of the vinyl chloride resin microparticles is typically less than 30 μm, preferably 10 μm or less, more preferably 5 μm or less, and preferably 0.1 μm or more, more preferably 1 μm or more. When the volume average particle diameter of the vinyl chloride resin microparticles is equal to or greater than the above-mentioned lower limit, the powder flowability of the resulting vinyl chloride resin composition can be further improved, for example, without excessively reducing the size of the particles used as a dusting agent. When the volume average particle diameter of the vinyl chloride resin microparticles is equal to or less than the above-mentioned upper limit, the meltability of the resulting vinyl chloride resin composition can be enhanced, and the surface smoothness of the resulting vinyl chloride resin molded article can be further improved. In the present invention, the "volume average particle diameter of the vinyl chloride resin microparticles" can be measured by laser diffraction in accordance with JIS Z8825.

[0027] -Content- The content of vinyl chloride resin microparticles in the vinyl chloride resin may be 0% by mass, but is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 30% by mass or less, and more preferably 20% by mass or less. If the content of vinyl chloride resin microparticles in the vinyl chloride resin is equal to or greater than the above-mentioned lower limit, the powder fluidity of the resulting vinyl chloride resin composition is further improved. Furthermore, if the content of vinyl chloride resin microparticles in the vinyl chloride resin is equal to or less than the above-mentioned upper limit, the physical strength of a vinyl chloride resin molded article formed using the resulting vinyl chloride resin composition can be further increased.

[0028] <<Additives>> Examples of additives to be kneaded with the vinyl chloride resin include plasticizers; lubricants; stabilizers such as perchloric acid-treated hydrotalcite, zeolite, β-diketone, and fatty acid metal salts; mold release agents; dusting agents other than the vinyl chloride resin fine particles; impact modifiers; perchloric acid compounds other than perchloric acid-treated hydrotalcite (e.g., sodium perchlorate and potassium perchlorate); antioxidants; mildew inhibitors; flame retardants; antistatic agents; fillers; light stabilizers; foaming agents; and pigments. These additives may be used alone or in combination of two or more in any ratio. Among these, from the viewpoint of improving the flexibility of the resulting vinyl chloride resin molded article and further improving the low-temperature tensile elongation, it is preferable that the additives include a plasticizer.

[0029] The plasticizer is not particularly limited, but it is preferable to use at least one of polyester and trimellitic acid ester. Plasticizers other than polyester and trimellitic acid ester (hereinafter, sometimes referred to as "other plasticizers") may also be used as the plasticizer. By using a plasticizer, the vinyl chloride resin molded body formed can exhibit sufficient flexibility, and can therefore be suitably used, for example, as an automotive interior material. When a polyester is kneaded as a plasticizer with vinyl chloride resin to form a kneaded product, the kneaded product may not be pulverized using a conventional disk-type pulverizer (disk mill) described in International Publication No. WO 2022 / 210779. However, according to the pulverization step of the method for producing a vinyl chloride resin composition of the present invention described below, which uses a rotary cutter, even a kneaded product containing polyester can be pulverized well, and a vinyl chloride resin composition capable of forming a vinyl chloride resin molded body having excellent low-temperature tensile elongation can be obtained.

[0030] The amount of plasticizer is preferably 40 parts by mass or more, more preferably 105 parts by mass or more, even more preferably 110 parts by mass or more, and preferably 200 parts by mass or less, more preferably 180 parts by mass or less, per 100 parts by mass of vinyl chloride resin. If the amount of plasticizer is above the lower limit per 100 parts by mass of vinyl chloride resin, the flexibility of the vinyl chloride resin molded body formed can be increased and the low-temperature tensile elongation can be further improved. On the other hand, if the amount of plasticizer is below the upper limit per 100 parts by mass of vinyl chloride resin, the kneaded product of vinyl chloride resin and additives can be well pulverized, while the low-temperature tensile elongation of the vinyl chloride resin molded body can be further improved. Note that when the plasticizer is used in a high amount (for example, 140 parts by mass or more per 100 parts by mass of vinyl chloride resin), the kneaded product may not be pulverized using conventional disk-type pulverizers (disk mills) such as those described in International Publication No. WO 2022 / 210779. However, according to the pulverization step of the method for producing a vinyl chloride resin composition of the present invention described below, which uses a rotary cutter, the kneaded product can be pulverized well even when the blending amount of plasticizer is high, and a vinyl chloride resin composition that can be used to form a vinyl chloride resin molded article having excellent low-temperature tensile elongation can be obtained well.

[0031] [Polyester] The plasticizer preferably contains a polyester, which can improve the heat shrinkage resistance of the vinyl chloride resin molded article formed.

[0032] The polyester that can be contained in the plasticizer is not particularly limited, and examples thereof include polyesters containing structural units derived from adipic acid (adipic acid-based polyesters), polyesters containing structural units derived from sebacic acid (sebacic acid-based polyesters), and polyesters containing structural units derived from phthalic acid (phthalic acid-based polyesters). These polyesters may be used alone or in combination of two or more in any ratio. Among these, from the viewpoint of further enhancing the heat shrinkage resistance of the vinyl chloride resin molded article to be formed, it is preferable to use a polyester containing structural units derived from adipic acid, and it is particularly preferable to use a polyester containing structural units derived from adipic acid and structural units derived from 3-methyl-1,5-pentanediol.

[0033] Hereinafter, for convenience of explanation, a polyester containing structural units derived from adipic acid and structural units derived from 3-methyl-1,5-pentanediol will be referred to as "polyester A." Here, polyester A containing the above-mentioned specified structural units may have structural units other than structural units derived from adipic acid and structural units derived from 3-methyl-1,5-pentanediol, but the total of structural units derived from adipic acid and structural units derived from 3-methyl-1,5-pentanediol is preferably 50% by mass or more, and more preferably 80% by mass or more, of all structural units. Furthermore, polyester A containing the above-mentioned specified structural units preferably has only structural units derived from adipic acid and structural units derived from 3-methyl-1,5-pentanediol as repeating units.

[0034] The polyester A containing the above-described predetermined structural unit can be obtained by condensation polymerization of adipic acid and 3-methyl-1,5-pentanediol, without any particular limitation. The condensation polymerization can be carried out in the presence of a catalyst. The condensation polymerization can be carried out using an alcohol and / or a monobasic acid as a terminal-terminating component. The condensation polymerization of adipic acid and 3-methyl-1,5-pentanediol and the termination reaction of the resulting condensation polymer with the terminal-terminating component can be carried out simultaneously or separately. The product obtained through the condensation polymerization and termination reaction can be subjected to post-treatment such as distillation. The reaction conditions for the condensation polymerization, such as the amounts of the monomers, catalyst, and terminal-terminating component used, can be any known condition. The polyester A containing the above-described predetermined structural unit may be a commercially available product.

[0035] The catalyst used in the condensation polymerization reaction is not particularly limited, and examples thereof include dibutyltin oxide and tetraalkyl titanate.

[0036] Examples of alcohols that can be used as end-stopping components include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, hexanol, isohexanol, heptanol, isoheptanol, octanol, isooctanol, 2-ethylhexanol, nonanol, isononanol, decanol, isodecanol, undecanol, isoundecanol, dodecanol, tridecanol, isotridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, cellosolve, carbitol, phenol, nonylphenol, benzyl alcohol, and mixtures thereof. Furthermore, examples of monobasic acids that can be used as end-stopping components include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, pivalic acid, caproic acid, heptanoic acid, caprylic acid, 2-ethylhexylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, benzoic acid, and mixtures thereof. Among these, 2-ethylhexanol is preferred as the end-stopping component.

[0037] The polyester A containing the predetermined structural unit preferably has a weight average molecular weight of 1,000 or more, more preferably 2,000 or more, and preferably 10,000 or less, more preferably 7,000 or less. The "weight average molecular weight" can be determined as a polystyrene-equivalent value by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent. The polyester A containing the predetermined structural unit preferably has an acid value of 1 or less. Furthermore, the polyester A containing the predetermined structural unit preferably has a hydroxyl value of 30 or less.

[0038] Furthermore, the viscosity of the polyester A containing the above-mentioned predetermined structural unit is preferably 500 mPa·s or more, more preferably 1000 mPa·s or more, and is preferably 8000 mPa·s or less, more preferably 5000 mPa·s or less. The "viscosity" can be measured in accordance with JIS Z8803 at a temperature of 23°C.

[0039] The content of polyester in the plasticizer is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more, and is preferably 97% by mass or less, and more preferably 96% by mass or less. If the content of polyester in the plasticizer is equal to or greater than the above-mentioned lower limit, the heat shrinkage resistance of the vinyl chloride resin molded article formed can be further improved. On the other hand, if the content of polyester in the plasticizer is equal to or less than the above-mentioned upper limit, the flexibility of the vinyl chloride resin molded article formed at low temperatures can be well maintained.

[0040] The blending amount of the polyester is preferably 40 parts by mass or more, more preferably 60 parts by mass or more, and even more preferably 80 parts by mass or more, and is preferably 200 parts by mass or less, and more preferably 160 parts by mass or less, per 100 parts by mass of the vinyl chloride resin. When the blending amount of the polyester is equal to or more than the above-mentioned lower limit, the heat shrinkage resistance of the vinyl chloride resin molded article formed can be further improved. On the other hand, when the blending amount of the polyester is equal to or less than the above-mentioned upper limit, the powder flowability of the resulting vinyl chloride resin composition can be improved.

[0041] - Trimellitic acid ester - The plasticizer preferably contains a trimellitic acid ester. If the plasticizer contains a trimellitic acid ester, the trimellitic acid ester is well absorbed into the vinyl chloride resin, thereby improving the powder fluidity of the resulting vinyl chloride resin composition. Furthermore, if the plasticizer contains a trimellitic acid ester, the flexibility of the resulting vinyl chloride resin molded article at low temperatures can be improved.

[0042] The trimellitic acid ester contained in the plasticizer is preferably an ester compound of trimellitic acid and a monohydric alcohol.

[0043] Specific examples of the monohydric alcohol include, but are not limited to, aliphatic alcohols such as 1-hexanol, 1-heptanol, 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, etc. Among these, the monohydric alcohol is preferably an aliphatic alcohol having 6 to 18 carbon atoms, and more preferably a linear aliphatic alcohol having 6 to 18 carbon atoms.

[0044] Among these, the trimellitic acid ester is preferably a triester product in which substantially all of the carboxy groups of trimellitic acid are esterified with the monohydric alcohol. The alcohol residues in the triester product may be derived from the same alcohol or from different alcohols. The trimellitic acid ester may be composed of a single compound or a mixture of different compounds.

[0045] Specific examples of suitable trimellitic acid esters include tri-n-hexyl trimellitate, tri-n-heptyl trimellitate, tri-n-octyl trimellitate, tri-(2-ethylhexyl) trimellitate, tri-n-nonyl trimellitate, tri-n-decyl trimellitate, triisodecyl trimellitate, tri-n-undecyl trimellitate, tri-n-dodecyl trimellitate, tri-n-alkyl trimellitate esters (esters having two or more alkyl groups with different carbon numbers [with the carbon number being 6 to 18] in the molecule), tri-n-alkyl trimellitate esters (esters having two or more alkyl groups with different carbon numbers [with the carbon number being 6 to 18] in the molecule), and mixtures thereof. More preferred specific examples of trimellitic acid esters include tri-n-octyl trimellitate, tri-(2-ethylhexyl) trimellitate, tri-n-nonyl trimellitate, tri-n-decyl trimellitate, tri-n-alkyl trimellitate (esters having two or more alkyl groups with different carbon numbers [however, the number of carbon atoms is 6 to 18] in the molecule), and mixtures thereof.

[0046] The content of the trimellitic acid ester in the plasticizer is preferably 5% by mass or more, more preferably 10% by mass or more, more preferably 97% by mass or less, and even more preferably 96% by mass or less. When the content of the trimellitic acid ester in the plasticizer is equal to or greater than the above-mentioned lower limit, the powder fluidity of the resulting vinyl chloride resin composition can be further increased, and the flexibility of the resulting vinyl chloride resin molded article at low temperatures can be further increased. On the other hand, when the content of the trimellitic acid ester in the plasticizer is equal to or less than the above-mentioned upper limit, the heat shrinkage resistance of the resulting vinyl chloride resin molded article can be improved.

[0047] The blending amount of the trimellitate ester is preferably 40 parts by mass or more, more preferably 60 parts by mass or more, and even more preferably 80 parts by mass or more, and is preferably 200 parts by mass or less, and more preferably 160 parts by mass or less, per 100 parts by mass of the vinyl chloride resin. When the blending amount of the trimellitate ester is equal to or greater than the above-mentioned lower limit, the powder fluidity of the resulting vinyl chloride resin composition can be further increased, and the flexibility of the resulting vinyl chloride resin molded article at low temperatures can be further increased. On the other hand, when the blending amount of the trimellitate ester is equal to or less than the above-mentioned upper limit, the heat shrinkage resistance of the resulting vinyl chloride resin molded article can be improved.

[0048] [Other Plasticizers] The plasticizer may optionally include other plasticizers in addition to the polyester and trimellitic acid ester described above.

[0049] Specific examples of other plasticizers include plasticizers other than the polyesters and trimellitic acid esters described above among the plasticizers described in WO 2016 / 098344. Among them, it is preferable to use epoxidized soybean oil from the viewpoint of further increasing the flexibility of the vinyl chloride resin molded article formed at low temperatures.

[0050] The content of the other plasticizer in the plasticizer is not particularly limited, but is preferably from 0% by mass to 15% by mass. When the content of the other plasticizer in the plasticizer is within the above range, the flexibility of the resulting vinyl chloride resin molded article at low temperatures after heating can be improved.

[0051] The amount of the other plasticizer is not particularly limited, but can be from 0 to 15 parts by mass per 100 parts by mass of the vinyl chloride resin. From the viewpoint of further enhancing the flexibility of the vinyl chloride resin molded article at low temperatures, it is preferable to use an epoxidized vegetable oil such as epoxidized soybean oil as the other plasticizer in an amount of from 2 to 7 parts by mass per 100 parts by mass of the vinyl chloride resin.

[0052] As the additives other than the plasticizer, for example, those described in WO 2016 / 098344 can be used, and the suitable blending amount thereof can be the same as that described in WO 2016 / 098344.

[0053] In the kneading step, for example, the vinyl chloride resin and the additives may be separately charged into a kneader described below and kneaded. However, it is preferable to premix the components to form a premix, which is then charged into the kneader and kneaded. If the components are premixed in advance and then the premix is ​​kneaded, the components can be more effectively mixed and dispersed in the resulting kneaded product and in the vinyl chloride resin composition obtained by pulverizing the kneaded product. Therefore, the low-temperature tensile elongation of a vinyl chloride resin molded article formed using the vinyl chloride resin composition can be further improved.

[0054] The method for premixing the above components is not particularly limited, and examples thereof include a method of mixing by dry blending. For example, a method is used in which components other than the dusting agent (including vinyl chloride resin fine particles) are mixed by dry blending, and then the dusting agent is added and mixed. Here, it is preferable to use a Henschel mixer for dry blending. In addition, the temperature during dry blending is not particularly limited, and is preferably 50°C or higher, more preferably 70°C or higher, and preferably 200°C or lower.

[0055] The pre-mixture containing the vinyl chloride resin and additives is preferably kneaded using a kneader, although there are no particular limitations thereon. Examples of kneaders that can be used include open-roll continuous kneaders, extruders, and twin-screw extruders. Among these, it is preferable to use a twin-screw extruder. For example, the "Kneedex" manufactured by Nippon Coke & Engineering Co., Ltd. can be used as the open-roll continuous kneader. For example, the "ZSK32Mc18" manufactured by Coperion can be used as the twin-screw extruder.

[0056] The temperature during kneading is not particularly limited, but is preferably 40° C. or higher and 200° C. or lower. For example, when kneading is performed using an open-roll continuous kneader (Kneedex), it is preferable to set the inlet temperature to 90 to 200° C., preferably 100 to 180° C., and the outlet temperature to 40 to 170° C., preferably 50 to 150° C. Furthermore, for example, when kneading is performed using a twin-screw extruder, it is preferable to set the barrel temperature to 30 to 140° C., the rotation speed to 200 rpm, and the resin temperature at the outlet to 150 to 200° C.

[0057] Furthermore, the kneaded product obtained in the kneading step is preferably formed into pellets by a known method, although this is not particularly limited. If the kneaded product obtained in the kneading step is formed into pellets, the kneaded product can be easily pulverized in the pulverization step described below to obtain a vinyl chloride resin composition.

[0058] <Pulverization Step> In the pulverization step, a pulverizer is used to pulverize the kneaded material obtained in the kneading step to obtain a powdered vinyl chloride resin composition. Here, the pulverizer used in the present invention is a shear-type pulverizer, also known as a rotary cutter or cutter mill, configured to pulverize the contents using a rotary blade concentrically attached to a shaft and a fixed blade corresponding to the rotary blade. In addition to the rotary blade and fixed blade attached to the shaft, the pulverizer usually further includes a shaft rotation mechanism; a hopper inside which the kneaded material is pulverized by the rotary blade and fixed blade; an inlet for introducing the kneaded material into the hopper; and an outlet for discharging the pulverized material.

[0059] The rotary blade is typically a flat blade and is concentrically attached to a rotatable shaft so that the blade surface extends horizontally. The fixed blade is also typically a flat blade and is fixed in the pulverizer so that the blade surface extends horizontally. The rotary blade and the fixed blade are arranged so that they mesh with each other via a clearance (gap) when the rotary blade is rotated. That is, the rotary blade rotates vertically together with the shaft by rotating the shaft vertically, and repeatedly meshes with the horizontally extending fixed blade. By repeatedly meshing the rotary blade and the fixed blade in this manner, the kneaded material fed into the pulverizer is repeatedly cut and pulverized by the rotary blade and the fixed blade. As a result, a powdered vinyl chloride resin composition is obtained.

[0060] Here, the clearance (gap) between the rotary blade and the fixed blade when they are meshed (i.e., when they are aligned horizontally in a straight line) is preferably 0.01 mm or more, more preferably 0.05 mm or more, and even more preferably 0.5 mm or more, and is preferably 5.0 mm or less, more preferably 3.0 mm or less, and even more preferably 2.0 mm or less. If the clearance between the rotary blade and the fixed blade is within the above-mentioned specified range, the kneaded material can be well pulverized, and a vinyl chloride resin composition can be obtained that can form a vinyl chloride resin molded product having even better low-temperature tensile elongation.

[0061] The number of rotary blades is not particularly limited, but is preferably 2 or more, and can be, for example, 4. Here, the intervals between the rotary blades (blade surfaces) are not particularly limited, but are preferably equal intervals.

[0062] The number of fixed blades is not particularly limited, but is preferably 2 or more, and more preferably 4 or more, and can be, for example, 8. The position of the fixed blade is not particularly limited, but can be, for example, provided directly below the hopper inlet.

[0063] An example of a crusher (rotary cutter) according to the present invention will be described below with reference to the drawings. FIG. 1 is a front view of an example of the crusher, FIG. 2 is a side view of the crusher, FIG. 3 is a plan cross-sectional view of the crusher, and FIG. 4 is a side cross-sectional view of the crusher. Referring to each figure, the crusher 1 has a pulley 2 on its side, which is connected to a motor 4 via a belt 3. The crusher 1 also has a hopper 9 composed of an upper cover 5, a side plate 6, and a screen 8 having openings 7. Within the hopper 9, a shaft 10 extending in the longitudinal direction of the crusher 1 is rotatably mounted by a bearing support 19. The pulley 2 is attached to one end of the shaft 10.

[0064] 3, two rotating plates 14 are fixed to the shaft 10. The inner surface of each rotating plate 14 is flush with the side plate 6, and a gap 15 is provided between the outer periphery of the rotating plate 14 and the side plate 6. The gap 15 communicates with a discharge port 16 (FIGS. 1 and 2) for discharging the pulverized material to the outside.

[0065] Referring to FIG. 4 , four rotary blades 11 are attached to a shaft 10 at regular intervals in a radial pattern, and two fixed blades 13 are attached to a receiving stand 12 at regular intervals. A screen 8 having a plurality of apertures 7 is provided below the rotary blades. The screen 8 is supported by a screen retainer 18. When the motor 4 is driven, the pulley 2 rotates via the belt 3, and the shaft attached to the pulley 2 rotates vertically (up and down in FIG. 4 ). This causes the rotary blades 11 to also rotate vertically (up and down in FIG. 4 ), repeatedly meshing with the fixed blades 13, whose blade surfaces extend horizontally (in the direction protruding from the page in FIG. 4 ). The mixture introduced into the hopper 9 through the hopper inlet 17 is repeatedly cut and pulverized by the rotary blades 11 and the fixed blades 13. When the kneaded material is pulverized to a size that can pass through the openings 7 of the screen 8, the pulverized material passes through the openings 7 of the screen 8 and is discharged from the discharge port 16 as a powdered vinyl chloride resin composition.

[0066] The pulverizer used in the present invention may be connected to devices such as a blower for air-transporting the pulverized material, a cyclone and rotary valve for separating the pulverized material from the air and extracting only the pulverized material, and a bag filter for recovering the finely pulverized material that could not be separated by the cyclone. An example of a pulverizer configured by connecting the above-mentioned devices to a pulverizer is the "SRC-200" manufactured by Yoshikosha.

[0067] (Vinyl chloride resin composition) The vinyl chloride resin composition is produced via the method for producing a vinyl chloride resin composition of the present invention described above. Therefore, the vinyl chloride resin composition contains at least the vinyl chloride resin and additives described above. Here, the suitable content ratios of the vinyl chloride resin (vinyl chloride resin particles, vinyl chloride resin fine particles) and additives such as plasticizers in the vinyl chloride resin composition can be the same as those described above in the section "Method for producing a vinyl chloride resin composition."

[0068] <Particle diameter D50> The particle diameter D50 of the vinyl chloride resin composition is preferably 300 μm or more, more preferably 340 μm or more, even more preferably 354 μm or more, and preferably 400 μm or less, more preferably 380 μm or less. If the particle diameter D50 of the vinyl chloride resin composition is within the above range, the vinyl chloride resin composition can be suitably used for powder molding, and is more suitably used for powder slush molding. The particle diameter D50 of the vinyl chloride resin composition can be controlled, for example, by changing the clearance between the rotary blade and the fixed blade, the size of the screen openings, etc. In addition, in the present invention, the particle diameter D50 of the vinyl chloride resin composition can be measured in accordance with JIS Z 8815 by the method described in the Examples.

[0069] <Drop Time> The drop time of the vinyl chloride resin composition is preferably 45 seconds or less, more preferably 35 seconds or less, and even more preferably 25 seconds or less. When the drop time of the vinyl chloride resin composition is not more than the above upper limit, the vinyl chloride resin composition has excellent powder fluidity, and therefore the vinyl chloride resin composition can be suitably used for powder molding, and can be suitably used for powder slush molding. In the present invention, the drop time of the vinyl chloride resin composition can be measured by the method described in the Examples.

[0070] <Melt Temperature> The melt temperature of the vinyl chloride resin composition is preferably 290°C or lower, more preferably 270°C or lower. When the melt temperature of the vinyl chloride resin composition is equal to or lower than the above upper limit, the vinyl chloride resin composition can be suitably used for powder molding, and can be suitably used for powder slush molding. The melt temperature of the vinyl chloride resin composition can be lowered by performing a kneading step. In the present invention, the melt temperature of the vinyl chloride resin composition can be measured by the method described in the Examples.

[0071] <aspect ratio b / l ３ > Aspect ratio b / l of vinyl chloride resin composition ３ The aspect ratio b / l of the vinyl chloride resin composition is preferably 0.550 or more, more preferably 0.600 or more, even more preferably 0.640 or more, and even more preferably 0.660 or more, and is preferably less than 0.698, more preferably 0.695 or less, and even more preferably 0.690 or less. ３ When the aspect ratio b / l of the vinyl chloride resin composition is within the above range, excellent powder flowability can be obtained even without adding vinyl chloride resin fine particles to the particle surfaces of the vinyl chloride resin composition after pulverization. ３ can be controlled, for example, by adjusting the clearance between the rotary blade and the fixed blade.

[0072] <Uses of Vinyl Chloride Resin Composition> The obtained vinyl chloride resin composition can be suitably used for powder molding, and more suitably used for powder slush molding.

[0073] (Vinyl chloride resin molded article) A vinyl chloride resin molded article can be obtained by molding the above-mentioned vinyl chloride resin composition by any method. Since the vinyl chloride resin molded article is formed using the vinyl chloride resin composition produced by the above-mentioned method for producing a vinyl chloride resin composition of the present invention, it usually contains at least the above-mentioned vinyl chloride resin and additives and has excellent low-temperature tensile elongation. Therefore, the vinyl chloride resin molded article can be suitably used as an automobile interior material such as the skin of an automobile instrument panel.

[0074] <Storage modulus at 40°C> The storage modulus of the vinyl chloride resin molded article at 40°C is preferably 30 MPa or less, more preferably 20 MPa or less, and even more preferably 10 MPa or less. If the storage modulus of the vinyl chloride resin molded article at 40°C is not more than the above upper limit, the vinyl chloride resin molded article has excellent flexibility and can be suitably used as an automobile interior material such as the surface of an automobile instrument panel. In the present invention, the storage modulus of the vinyl chloride resin molded article can be measured by the method described in the examples.

[0075] <Production Method> When a vinyl chloride resin molded article is formed by powder slush molding, the mold temperature during powder slush molding is not particularly limited, but is preferably 200°C or higher, more preferably 220°C or higher, and preferably 300°C or lower, and more preferably 280°C or lower. When producing a vinyl chloride resin molded article, the temperature is not particularly limited, and the following method, for example, can be used. That is, a vinyl chloride resin composition is sprinkled onto a mold at the above temperature range, and the mold is left for 5 to 30 seconds, after which the excess vinyl chloride resin composition is shaken off. The mold is then left for 30 seconds to 3 minutes at a desired temperature. The mold is then cooled to 10 to 60°C, and the resulting vinyl chloride resin molded article is demolded from the mold. A sheet-like molded article conforming to the shape of the mold is then obtained.

[0076] (Laminate) The laminate has a polyurethane foam molded body and the above-mentioned vinyl chloride resin molded body. The vinyl chloride resin molded body usually constitutes one surface of the laminate. The laminate has a vinyl chloride resin molded body excellent in low-temperature tensile elongation formed using, for example, a vinyl chloride resin composition produced by the above-mentioned method for producing a vinyl chloride resin composition of the present invention, and is therefore suitable for use as an automobile interior part, particularly as an automobile interior material for forming an automobile instrument panel.

[0077] Here, the method for laminating a polyurethane foam molded body and a vinyl chloride resin molded body is not particularly limited, and the following methods can be used, for example. That is, (1) a method in which a polyurethane foam molded body and a vinyl chloride resin molded body are separately prepared and then bonded together by heat fusion, heat adhesion, or using a known adhesive, etc.; (2) a method in which isocyanates and polyols, which are raw materials for the polyurethane foam molded body, are reacted on the vinyl chloride resin molded body to polymerize, and polyurethane is foamed by a known method, thereby directly forming a polyurethane foam molded body on the vinyl chloride resin molded body; etc. Among these, the latter method (2) is preferred because of its simple process and the ease with which the vinyl chloride resin molded body and the polyurethane foam molded body can be firmly bonded together even when laminates of various shapes are obtained.

[0078] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. In the following description, "%" and "parts" representing amounts are based on mass unless otherwise specified. The physical properties of vinyl chloride resin compositions and vinyl chloride resin molded articles were measured or evaluated by the following methods.

[0079] <Powder Fluidity> For the vinyl chloride resin compositions obtained in the Examples and Comparative Examples, bulk density was measured from the weight of the composition in a 100 ml container using a bulk specific gravity measuring device as specified in JIS-K-6720. The powder in the 100 ml container obtained at that time was returned to the bulk specific gravity measuring device, and the time until all the powder flowed after immediately opening the damper was measured to obtain the falling time. Note that if the powder did not completely flow after waiting for one minute, it was recorded as "not flowing." All of the above operations were performed at room temperature (23°C). A shorter falling time indicates better powder fluidity for the vinyl chloride resin composition. <Particle Diameter D50> For the vinyl chloride resin compositions obtained in the Examples and Comparative Examples, particle diameter D50 was calculated using the following sieving device and sieve based on the "General Rules for Sieving Test Methods" as specified in JIS Z 8815. Sieving device: Robot Sifter RPS-105M (manufactured by Seishin Kogyo Co., Ltd.) Sieves: sieves with openings of 710 μm, 600 μm, 425 μm, 355 μm, 212 μm, 180 μm, 150 μm, and 106 μm The percentage of particles remaining on the sieve and the cumulative percentage of particles remaining on the sieve were calculated using the following formulas (1) and (2). R = (m / T) × 100 (1) Q = 100 - ΣR (2) R: sieve percentage [%] m: sieve mass [g] T: recovery test sample mass [g] Q: cumulative sieve percentage [%] ΣR: cumulative sieve percentage [%] Then, the sieve percentages were calculated in ascending order of mesh size, and the sieve openings and percentages before and after exceeding 50% were recorded. These two points were connected by a straight line to determine the 50% point, which was designated as the particle diameter D50. <Melting Temperature> The melting temperatures of the vinyl chloride resin compositions obtained in the examples and comparative examples were measured using a heated mold. Specifically, the mold was placed on a hot plate heated in stages at equal intervals from 170°C to 270°C, and a stepwise heated mold measuring 300 mm long, 60 mm wide, and 4 mm deep was obtained. The mold temperature was then measured and recorded at five points spaced 50 mm apart from the end of the mold in the longitudinal direction, and these were designated as the thermometer side points.The vinyl chloride resin composition was then sprinkled onto the mold that had been heated in stages to a thickness of 1 mm, and allowed to stand for 45 seconds to melt the composition.Next, the excess vinyl chloride resin composition was shaken off, and the mold was cooled with water to obtain a vinyl chloride resin molded sheet in which the vinyl chloride resin was molded into a belt shape. Then, marks were written on the vinyl chloride resin molded sheet at positions corresponding to the five thermometer-side points where the mold temperature was measured, and the sheet was then demolded from the mold. The surface of the demolded vinyl chloride resin molded sheet was visually observed, and the point where the vinyl chloride resin composition melted was designated the melting point. Of the two temperature measurement points sandwiching the melting point, the mold temperature at the higher thermometer-side point was designated the higher-temperature side mold temperature MLDH [°C], the mold temperature at the lower thermometer-side point was designated the lower-temperature side mold temperature MLDL [°C], and the distance from the lower thermometer-side point to the melting point was designated TML [mm]. The melting point temperature, i.e., the melting temperature TM [°C] of the vinyl chloride resin composition was calculated using the following formula: Melting temperature TM = (MLDH - MLDL) x (TML / 50) + MLDL [°C] TM: Melting temperature [°C] MLDH: High-temperature mold temperature [°C] MLDL: Low-temperature mold temperature [°C] TML: Distance from the low-temperature temperature measurement point to the melting point [mm] The melted point (melting point) was determined as a point on the molded vinyl chloride resin sheet that had a smooth surface without any particle-like residue. The lower the melting temperature, the better the vinyl chloride resin composition's meltability. <Storage Modulus at 40°C> Measurement samples were prepared by punching out vinyl chloride resin molded articles (sheets) produced in the Examples and Comparative Examples to a size of 10 mm wide x 40 mm long. Then, the storage modulus (MPa) of the measurement samples was measured at 40°C in accordance with JIS K7244-4 at a frequency of 10 Hz, a heating rate of 2°C / min, and a measurement temperature range of -90°C to +100°C. The lower the storage modulus at 40°C, the more excellent the flexibility of the vinyl chloride resin molded article. <Tensile Test> The vinyl chloride resin molded articles (sheets) produced in the Examples and Comparative Examples were punched out with a No. 1 dumbbell as specified in JIS K6251 to prepare measurement samples. The measurement samples were then measured for tensile elongation (%) and tensile stress (MPa) at -10°C at a pulling rate of 200 mm / min in accordance with JIS K7113. The higher the tensile elongation value, the more excellent the vinyl chloride resin molded article's low-temperature tensile elongation. <Aspect Ratio b / l. ３For the vinyl chloride resin compositions obtained in the examples and comparative examples, the particle width X was measured using a dynamic image analysis (Camsizer X2 (X-JET)) that records the projection of the shadow of the particulate matter with a camera to obtain the particle shape. Ｃ　ｍｉｎ and particle length X Ｆｅ　ＭＡＸ The volume-based aspect ratio b / l was calculated using the following formula: ３ was calculated. Here, the particle width X Ｃ　ｍｉｎ is the total measured particle width X Ｃ indicates the narrowest particle width among Ｆｅ　ＭＡＸ is the total measured Feret diameter X Ｆｅ Specifically, a powder sample of about 1 to 5 g is placed in the chute, and the aspect ratio b / l is measured with a feeder vibration of 70%, a dispersion pressure of 50 kPa, and 10,000 captured images. ３ The calculation was carried out using the CAMSIZER X2 evaluation software DIMENSIONS. Aspect ratio b / l ３ = particle width Ｃ　ｍｉｎ / particle length Ｆｅ　ＭＡＸ

[0080] (Production Example 1) <Preparation of Premix A> Of the ingredients shown in Table 1, all ingredients except for the plasticizer (trimellitic acid ester, adipic acid polyester, and epoxidized soybean oil) and the vinyl chloride resin fine particles serving as a dusting agent were placed in a Henschel mixer and mixed. Then, when the temperature of the mixture rose to 80°C, all of the plasticizer was added, and the mixture was allowed to dry up (referring to a state in which the plasticizer was absorbed into the vinyl chloride resin particles serving as the vinyl chloride resin, and the mixture became smooth). Then, when the dried-up mixture was cooled to a temperature of 70°C or below, the vinyl chloride resin fine particles serving as a dusting agent were added, and Premix A was prepared.

[0081] (Production Example 2) <Preparation of Premix B> Premix B was prepared in the same manner as in Production Example 1, except that the types and / or blending ratios of the vinyl chloride resin and various additives in Production Example 1 were changed as shown in Table 1.

[0082] (Production Example 3) <Preparation of Premix C> Premix C was prepared in the same manner as in Production Example 1, except that the types and / or blending ratios of the vinyl chloride resin and various additives in Production Example 1 were changed as shown in Table 1.

[0083] (Example 1) <Kneading Step> The premix A prepared in Production Example 1 was kneaded using a co-rotating twin-screw extruder ("ZSK32Mc18" manufactured by Coperion, diameter: 32 mm, L / D = 52) equipped with a three-hole die with a diameter of 5 mm under conditions of a barrel temperature of 30 to 140°C, a rotation speed of 200 rpm, and a discharge rate of 25 kg / h. The kneaded product was then extruded so that the resin temperature at the outlet became 150 to 200°C, thereby obtaining strands. The obtained strands were cooled in a water tank and then cut with a pelletizer to obtain pellets with a diameter of approximately 3 mm and a length of approximately 2 mm.

[0084] <Pulverization Step> The obtained pellets were put into a pulverizer ("SRC-200" manufactured by Yoshikosha Co., Ltd.) equipped with a pulverizer (rotary cutter) set at 4 rotary blades and 8 fixed blades, the rotation speed of the rotary blades = 1000 rpm, and the clearance between the rotary blades and the fixed blades = 0.5 mm, and pulverized to obtain a vinyl chloride resin composition. The falling time, bulk density, particle diameter D50, melting temperature, and aspect ratio b / l of the obtained vinyl chloride resin composition were then measured. ３ The results are shown in Table 2.

[0085] <Formation of Vinyl Chloride Resin Molded Article> The obtained vinyl chloride resin composition was sprinkled onto a textured mold heated to 250°C, left to melt for a desired period of time, and then the excess vinyl chloride resin composition was shaken off. The textured mold onto which the vinyl chloride resin composition had been sprinkled was then placed in an oven set to 200°C, and 60 seconds after being placed thereon, the textured mold was cooled with cooling water. When the mold temperature had cooled to 40°C, a vinyl chloride resin molded sheet measuring 145 mm x 175 mm x 1 mm was removed from the mold as a vinyl chloride resin molded article. The storage modulus and low-temperature tensile elongation of the vinyl chloride resin molded sheet were then measured and evaluated. The results are shown in Table 2.

[0086] (Example 2) A vinyl chloride resin composition and a vinyl chloride resin molded article were produced in the same manner as in Example 1, except that premix B was used instead of premix A. Various measurements and evaluations were carried out. The results are shown in Table 2.

[0087] (Example 3) A vinyl chloride resin composition and a vinyl chloride resin molded article were produced in the same manner as in Example 1, except that premix C was used instead of premix A. Various measurements and evaluations were carried out. The results are shown in Table 2.

[0088] Comparative Example 1 Various measurements and evaluations were carried out in the same manner as in Example 2, except that the kneading step and the pulverization step were not carried out and premix B was used as a vinyl chloride resin composition as is to produce a vinyl chloride resin molded article. The results are shown in Table 2.

[0089] Comparative Example 2 Various measurements and evaluations were carried out in the same manner as in Example 3, except that the kneading step and the pulverization step were not carried out and Premix C was used as is as the vinyl chloride resin composition to produce a vinyl chloride resin molded article. The results are shown in Table 2.

[0090] Comparative Example 3 A vinyl chloride resin composition and a vinyl chloride resin molded product were produced in the same manner as in Example 1, except that in the pulverization step, instead of the rotary cutter, a disk mill with a cooling mechanism (manufactured by Nippon Coke and Engineering Co., Ltd., Centri-cutter "UCM150") set under the following conditions: rotary blade temperature: -10°C, rotary blade gap: 0.2 mm, rotary blade rotation speed: 600 Hz was used to carry out pulverization. The results are shown in Table 2.

[0091] Comparative Example 4 An attempt was made to produce a vinyl chloride resin composition in the same manner as in Example 2, except that in the pulverization step, instead of the rotary cutter, pulverization was carried out using a disk mill with a cooling mechanism (manufactured by Nippon Coke and Engineering Co., Ltd., Centri-cutter "UCM150") set under the following conditions: rotary blade temperature: -10°C, rotary blade gap: 0.2 mm, rotary blade rotation speed: 600 Hz. However, the kneaded product (pellets) could not be pulverized, and a vinyl chloride resin composition and a vinyl chloride resin molded article could not be produced.

[0092] Comparative Example 5 An attempt was made to produce a vinyl chloride resin composition in the same manner as in Example 3, except that in the pulverization step, instead of the rotary cutter, pulverization was carried out using a disk mill with a cooling mechanism (manufactured by Nippon Coke and Engineering Co., Ltd., Centri-cutter "UCM150") set under the following conditions: rotary blade temperature: -10°C, rotary blade gap: 0.2 mm, rotary blade rotation speed: 600 Hz. However, the kneaded product (pellets) could not be pulverized, and a vinyl chloride resin composition and a vinyl chloride resin molded article could not be produced.

[0093] (Comparative Example 6) A vinyl chloride resin composition and a vinyl chloride resin molded product were produced, and various measurements and evaluations were carried out, in the same manner as in Example 1, except that in the pulverization step, instead of using a rotary cutter, the kneaded product (pellets) was pulverized by freeze pulverization as described below. The results are shown in Table 2. <Freeze pulverization> The obtained pellets were charged into a hammer-type pulverizer adjusted to −90°C using liquid nitrogen and pulverized to obtain a vinyl chloride resin composition.

[0094] Comparative Example 7 A vinyl chloride resin composition and a vinyl chloride resin molded product were produced, and various measurements and evaluations were carried out, in the same manner as in Example 2, except that in the pulverization step, instead of using a rotary cutter, the kneaded product (pellets) was pulverized by freeze pulverization as described below. The results are shown in Table 2. <Freeze pulverization> The obtained pellets were placed in a hammer-type pulverizer adjusted to −90°C using liquid nitrogen and pulverized to obtain a vinyl chloride resin composition.

[0095] (Comparative Example 8) A vinyl chloride resin composition and a vinyl chloride resin molded product were produced, and various measurements and evaluations were carried out, in the same manner as in Example 3, except that in the pulverization step, the kneaded product (pellets) was pulverized by freeze pulverization as described below instead of using a rotary cutter. The results are shown in Table 2. <Freeze pulverization> The obtained pellets were placed in a hammer-type pulverizer adjusted to −90°C using liquid nitrogen and pulverized to obtain a vinyl chloride resin composition. 1) Shin-Dai-Ichi Vinyl Corporation, product name "ZEST (registered trademark) 1700ZI" (prepared by suspension polymerization, average degree of polymerization: 1700, volume average particle size: 130 μm) 2) Shin-Dai-Ichi Vinyl Corporation, product name "ZEST (registered trademark) 1300SI" (prepared by suspension polymerization, average degree of polymerization: 1300, volume average particle size: 132 μm) 3) Shin-Dai-Ichi Vinyl Corporation, product name "ZEST PQLTX" (prepared by emulsion polymerization, average degree of polymerization: 800, volume average particle size: 1.8 μm) 4) Kao Corporation, product name "Trimex N-08" 5) Zhongshan Unicizers Industrial Co., Ltd., product name "UN620" 6) ADEKA Corporation, product name "Adeka Cizer HPN-3130" 7) ADEKA Corporation, product name "ADEKA CIZER O-130S" 8) Kyowa Chemical Industry Co., Ltd., product name "ALCAMIZER (registered trademark) 5" 9) Mizusawa Industrial Chemicals, Ltd., product name "MIZUKALIZER DS" 10) Showa Denko K.K., product name "KARENZ DK-1" 11) Sakai Chemical Industry Co., Ltd., product name "SAKAISZ2000" 12) ADEKA Corporation, product name "ADEKA STAB LS-12" 13) Mitsubishi Chemical Corporation, product name "SULIPAX O" (melting point: 119°C) 14) Dainichiseika Color & Chemicals Co., Ltd., product name "DAP 4720 Black"

[0096] The results shown in Table 2 show that in Examples 1 to 3, in which pulverization was carried out using a pulverizer (rotary cutter) configured to pulverize the contents with a rotary blade attached concentrically to a shaft and a fixed blade corresponding to the rotary blade, vinyl chloride resin molded products excellent in low-temperature tensile elongation could be obtained.

[0097] According to the present invention, there is provided a method for producing a vinyl chloride resin composition that can form a vinyl chloride resin molded article having excellent low-temperature tensile elongation.

[0098] REFERENCE SIGNS LIST 1 Crusher 2 Pulley 3 Belt 4 Motor 5 Top cover 6 Side plate 7 Opening 8 Screen 9 Hopper 10 Shaft 11 Rotary blade 12 Receiving base 13 Fixed blade 14 Rotary plate 15 Gap 16 Discharge outlet 17 Hopper inlet 18 Screen holder 19 Bearing holder

Claims

1. A method for producing a vinyl chloride resin composition, comprising: a kneading step of kneading vinyl chloride resin and additives to obtain a kneaded mixture; and a crushing step of crushing the kneaded mixture using a crusher, wherein the crusher is configured to crush the contents with a rotary blade attached concentrically to a shaft and a fixed blade corresponding to the rotary blade.

2. The method for producing a vinyl chloride resin composition according to claim 1, wherein the clearance between the rotary blade and the fixed blade is 0.01 mm or more and 2.0 mm or less.

3. A method for producing a vinyl chloride resin composition as described in claim 1, wherein the additive comprises a plasticizer in a proportion of 40 parts by mass or more and 200 parts by mass or less per 100 parts by mass of the vinyl chloride resin.

4. The method for producing a vinyl chloride resin composition according to claim 1, wherein the kneading step includes a step of pelletizing the kneaded mixture.

5. Aspect ratio b / l of the vinyl chloride resin composition ３ The method for producing a vinyl chloride resin composition according to any one of claims 1 to 4, wherein the Mn is 0.550 or more and less than 0.698.

Images