Vinyl chloride resin composition for powder molding, vinyl chloride resin molded body, and laminate

Abstract

The present invention aims to provide a powder molding vinyl chloride resin composition capable of forming a vinyl chloride resin molded body having few pinholes. The powder molding vinyl chloride resin composition of the present invention is characterized by containing a vinyl chloride resin, a plasticizer containing at least one of a trimellitate ester and a polyester, and an acrylic polymer having a weight average molecular weight of 1,000 or more and 50,000 or less. In addition, the powder molding vinyl chloride resin composition is preferably used for powder slush molding.

Description

Technical Field

[0001] This invention relates to a vinyl chloride resin composition for powder molding, a vinyl chloride resin molded body, and a laminate. Background Technology

[0002] Vinyl chloride resins typically exhibit excellent cold resistance, heat resistance, and oil resistance, making them suitable for a wide range of applications.

[0003] Specifically, for example, in the formation of automotive interior components such as car dashboards and door trims, automotive interior materials such as skins formed from vinyl chloride resin molding bodies and laminates formed by adding foamed materials such as polyurethane foam to skins formed from vinyl chloride resin molding bodies are used.

[0004] Furthermore, the vinyl chloride resin molded body constituting the skin of automotive interior parts such as the dashboard can be manufactured by powder molding of a vinyl chloride resin composition containing additives such as vinyl chloride resin, plasticizer, and release agent using known molding methods such as powder slush molding (for example, see Patent Document 1).

[0005] Specifically, for example, in Patent Document 1, a skin formed from a vinyl chloride resin molded body is manufactured by powder slush molding of a vinyl chloride resin composition containing plasticizers such as vinyl chloride resin, trimellitate and polyester, and additives such as 12-hydroxystearic acid as a release agent.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2020 / 090556. Summary of the Invention

[0009] The problem the invention aims to solve

[0010] Here, when the vinyl chloride resin composition is powder molded, tiny pores (hereinafter referred to as "micropores") are sometimes generated on the surface of the formed vinyl chloride resin molded body. The fewer micropores on the surface of the vinyl chloride resin molded body, the better the appearance, and therefore it is suitable for use as the surface of automotive interior parts, etc.

[0011] However, the aforementioned conventional vinyl chloride resin compositions have room for improvement in reducing the micropores on the surface of the formed vinyl chloride resin molded articles.

[0012] Therefore, the object of the present invention is to provide a vinyl chloride resin composition for powder molding that can form vinyl chloride resin molded articles with few micropores.

[0013] Furthermore, the present invention aims to provide a vinyl chloride resin molded article with fewer micropores.

[0014] Furthermore, the object of the present invention is to provide a laminate having the vinyl chloride resin molded body.

[0015] Solution for solving the problem

[0016] The inventors conducted in-depth research with the aim of solving the above-mentioned problems. Then, the inventors discovered that if a vinyl chloride resin composition containing vinyl chloride resin, a specified plasticizer, and an acrylic polymer with a weight-average molecular weight within a specified range is subjected to powder molding, a vinyl chloride resin molded article with fewer micropores can be obtained, thereby completing the present invention.

[0017] That is, the purpose of the present invention is to advantageously solve the above-mentioned problems. The present invention is [1] a vinyl chloride resin composition for powder molding, which comprises vinyl chloride resin, a plasticizer containing at least one of trimellitate and polyester, and an acrylic polymer with a weight average molecular weight of 1,000 or more and 50,000 or less.

[0018] If a vinyl chloride resin composition containing vinyl chloride resin, a specified plasticizer, and an acrylic polymer with a weight-average molecular weight within a specified range is powder molded, a vinyl chloride resin molded body with few micropores can be formed.

[0019] In addition, in this invention, the "weight-average molecular weight" of acrylic polymers refers to the converted value based on standard polystyrene, determined by gel permeation chromatography.

[0020] [2] In the above-mentioned [1] vinyl chloride resin composition for powder molding, it is preferable that the content of the above-mentioned acrylic polymer is 0.05 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the above-mentioned vinyl chloride resin.

[0021] If the content of acrylic polymer in the vinyl chloride resin composition for powder molding is within the range specified above, the micropores on the surface of the formed vinyl chloride resin molded body can be further reduced.

[0022] [3] In the above-mentioned [1] or [2] vinyl chloride resin composition for powder molding, it is preferable that the total content of the above-mentioned trimellitate and the above-mentioned polyester is 30 parts by mass or more and 200 parts by mass or less relative to 100 parts by mass of the above-mentioned vinyl chloride resin.

[0023] If the total content of trimellitate and polyester in the vinyl chloride resin composition for powder molding is within the range specified above, the tensile properties (especially elongation) of the formed vinyl chloride resin molded article can be further improved.

[0024] [4] In any of the above [1] to [3], the vinyl chloride resin composition for powder molding preferably contains a structural unit derived from 2-ethylhexyl acrylate.

[0025] If an acrylic polymer containing structural units derived from 2-ethylhexyl acrylate is used, the micropores on the surface of the formed vinyl chloride resin molded body can be further reduced.

[0026] [5] Of the vinyl chloride resin compositions for powder molding in any of the above [1] to [4], it is preferred that the vinyl chloride resin composition for powder molding is used for powder slush molding.

[0027] If the vinyl chloride resin composition for powder molding is used in powder slush molding, it is easier to obtain vinyl chloride resin molded articles that can be well used as automotive interior materials such as dashboard covers.

[0028] Furthermore, the purpose of this invention is to advantageously solve the above-mentioned problems. This invention is [6] a vinyl chloride resin molded body, which is formed by powder molding of the vinyl chloride resin composition for powder molding of any one of [1] to [5] above.

[0029] The vinyl chloride resin molded body obtained by powder molding the above-mentioned vinyl chloride resin composition for powder molding has few micropores and excellent appearance.

[0030] [7] The vinyl chloride resin molded body described above [6] is preferably used for the surface of automotive interior parts.

[0031] This is because if vinyl chloride resin moldings are used for the surface of automotive interior parts, it is possible to manufacture automotive interior parts such as dashboards with fewer micropores and a superior appearance.

[0032] Furthermore, the object of the present invention is to advantageously solve the above-mentioned problems. The present invention is [8] a laminate having a foamed polyurethane molded body and the vinyl chloride resin molded body of [6] or [7] described above.

[0033] The laminate having a foamed polyurethane molded body and the aforementioned vinyl chloride resin molded body is suitable for use as an automotive interior material that can be used to manufacture automotive interior parts such as automotive dashboards with excellent appearance.

[0034] Invention Effects

[0035] According to the present invention, a vinyl chloride resin composition for powder molding capable of forming vinyl chloride resin molded articles with few micropores can be provided.

[0036] Furthermore, according to the present invention, vinyl chloride resin molded articles with fewer micropores can be provided.

[0037] Furthermore, according to the present invention, it is possible to provide a laminate having the vinyl chloride resin molded body. Detailed Implementation

[0038] The embodiments of the present invention will now be described in detail.

[0039] The vinyl chloride resin composition for powder molding of the present invention can be used, for example, when powder molding into a vinyl chloride resin molded body of the present invention. Furthermore, the vinyl chloride resin molded body formed by powder molding using the vinyl chloride resin composition for powder molding of the present invention is suitable for use as an automotive interior material, such as the surface material of automotive interior parts like dashboards and door trims.

[0040] Furthermore, the vinyl chloride resin molded body of the present invention can be used, for example, in forming the laminate of the present invention. Moreover, the laminate formed using the vinyl chloride resin molded body of the present invention is suitable for use as an automotive interior material, for example, in manufacturing automotive interior parts such as dashboards and door trims.

[0041] (Vinyl chloride resin composition for powder molding)

[0042] The vinyl chloride resin composition for powder molding of the present invention comprises (a) vinyl chloride resin, (b) a plasticizer comprising at least one of trimellitate and polyester, and (c) an acrylic polymer with a weight-average molecular weight within a specified range, and may optionally further comprise additives. Furthermore, since the vinyl chloride resin composition for powder molding of the present invention comprises at least the aforementioned (a) vinyl chloride resin, (b) plasticizer, and (c) acrylic polymer, the pores on the surface of the formed vinyl chloride resin molded article can be reduced. Therefore, if the vinyl chloride resin composition for powder molding of the present invention is used, a vinyl chloride resin molded article suitable for, for example, automotive interior materials such as dashboard panels and door trim panels with low pore size and excellent appearance can be obtained.

[0043] Furthermore, for example, from the viewpoint that vinyl chloride resin molded articles that can be well used as automotive interior materials can be easily obtained using the vinyl chloride resin composition for powder molding of the present invention, the vinyl chloride resin composition for powder molding of the present invention is preferably used for powder slush molding.

[0044] <(a) Vinyl chloride resin>

[0045] As (a) vinyl chloride resin, granular vinyl chloride resin is typically used. Furthermore, as (a) vinyl chloride resin, it can contain, for example, one or more types of vinyl chloride resin particles, and can optionally further contain one or more types of vinyl chloride resin microparticles. In particular, (a) vinyl chloride resin preferably contains at least vinyl chloride resin particles, and more preferably contains both vinyl chloride resin particles and vinyl chloride resin microparticles.

[0046] Moreover, (a) vinyl chloride resin can also be manufactured by any of the existing known manufacturing methods, such as suspension polymerization, emulsion polymerization, solution polymerization, and bulk polymerization.

[0047] In addition, in this specification, "resin particles" refers to particles with a diameter of 30 μm or larger, and "resin microparticles" refers to particles with a diameter of less than 30 μm.

[0048] Furthermore, as for (a) vinyl chloride resin, in addition to homopolymers formed from vinyl chloride monomer units, examples include vinyl chloride copolymers preferably containing 50% by mass or more, more preferably 70% by mass or more, of vinyl chloride monomer units. Moreover, as specific examples of monomers (comonomers) capable of constituting vinyl chloride copolymers and capable of copolymerizing with vinyl chloride monomers, monomers described, for example, in International Publication No. 2016 / 098344 can be used. Furthermore, these components can be used individually or in combination of two or more in any ratio.

[0049] <<Vinyl Chloride Resin Granules>>

[0050] In vinyl chloride resin compositions for powder molding, vinyl chloride resin particles typically function as the matrix resin (substrate). Furthermore, vinyl chloride resin particles are preferably manufactured via suspension polymerization.

[0051] [Average Degree of Polymerization]

[0052] Furthermore, 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, more preferably 5000 or less, more preferably 3000 or less, and even more preferably 2800 or less. This is because if the average degree of polymerization of the vinyl chloride resin constituting the vinyl chloride resin particles is at or above the aforementioned lower limit, the physical strength of the vinyl chloride resin molded body formed using the vinyl chloride resin composition for powder molding can be sufficiently ensured, and for example, tensile properties, especially tensile elongation, are better. Moreover, the vinyl chloride resin molded body with good tensile elongation is suitable for use as an automotive interior material such as the dashboard of an automobile with excellent ductility, for example, when an airbag inflates and deploys, the fragments do not scatter but crack according to the design. In addition, if the average degree of polymerization of the vinyl chloride resin constituting the vinyl chloride resin particles is at or below the aforementioned upper limit, the meltability of the vinyl chloride resin composition for powder molding can be improved.

[0053] In addition, in this invention, the "average degree of polymerization" can be measured according to JIS K6720-2.

[0054] [Average Particle Size]

[0055] Furthermore, the average particle size of the vinyl chloride resin particles is typically 30 μm or more, preferably 50 μm or more, more preferably 100 μm or more, more preferably 500 μm or less, and more preferably 200 μm or less. This is because if the average particle size of the vinyl chloride resin particles is above or below the aforementioned lower limit, the powder flowability of the vinyl chloride resin composition for powder molding is further improved. Furthermore, if the average particle size of the vinyl chloride resin particles is below or below the aforementioned upper limit, the meltability of the vinyl chloride resin composition for powder molding is further improved, and the surface smoothness of the vinyl chloride resin molded article formed using this composition can be improved.

[0056] In addition, in this invention, the "average particle size" can be measured as the volume average particle size by laser diffraction in accordance with JIS Z8825.

[0057] [Contains percentage]

[0058] Furthermore, the content of vinyl chloride resin particles in (a) vinyl chloride resin is preferably 70% by mass or more, more preferably 80% by mass or more, and can be 100% by mass, preferably 95% by mass or less, and more preferably 90% by mass or less. This is because if the content of vinyl chloride resin particles in (a) vinyl chloride resin is at or above the aforementioned lower limit, the physical strength of the vinyl chloride resin molded article formed using the vinyl chloride resin composition for powder molding can be sufficiently ensured, and the tensile elongation is good. Furthermore, if the content of vinyl chloride resin particles in (a) vinyl chloride resin is at or below the aforementioned upper limit, the powder flowability of the vinyl chloride resin composition for powder molding is improved.

[0059] <<Vinyl Chloride Resin Microparticles>>

[0060] In vinyl chloride resin compositions for powder molding, vinyl chloride resin microparticles typically function as a dusting agent (powder flowability improver). Furthermore, vinyl chloride resin microparticles are preferably manufactured via emulsion polymerization.

[0061] [Average Degree of Polymerization]

[0062] Furthermore, 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, more preferably 2000 or less, and more preferably 1800 or less. This is because if the average degree of polymerization of the vinyl chloride resin constituting the vinyl chloride resin microparticles as a separating agent is above the aforementioned lower limit, the powder flowability of the vinyl chloride resin composition for powder molding becomes better, and the tensile elongation of the molded article obtained using the composition becomes better. Furthermore, if the average degree of polymerization of the vinyl chloride resin constituting the vinyl chloride resin microparticles is below the aforementioned upper limit, the meltability of the vinyl chloride resin composition for powder molding is improved, and the surface smoothness of the vinyl chloride resin molded article formed using the composition is improved.

[0063] [Average Particle Size]

[0064] Furthermore, the average particle size of the vinyl chloride resin particles is typically less than 30 μm, preferably 10 μm or less, more preferably 5 μm or less, more preferably 0.1 μm or more, and even more preferably 1 μm or more. This is because if the average particle size of the vinyl chloride resin particles is at or above the aforementioned lower limit, the size of the separating agent can be prevented from being too small, resulting in better powder flowability of the vinyl chloride resin composition for powder molding. Furthermore, if the average particle size of the vinyl chloride resin particles is at or below the aforementioned upper limit, the meltability of the vinyl chloride resin composition for powder molding is further improved, thereby further improving the surface smoothness of the formed vinyl chloride resin molded body.

[0065] [Contains percentage]

[0066] Furthermore, the content of vinyl chloride resin particles in (a) vinyl chloride resin can be 0% by mass, preferably 5% by mass or more, more preferably 10% by mass or more, preferably 30% by mass or less, and more preferably 20% by mass or less. This is because if the content of vinyl chloride resin particles in (a) vinyl chloride resin is at or above the aforementioned lower limit, the powder flowability of the vinyl chloride resin composition for powder molding is further improved. Furthermore, if the content of vinyl chloride resin particles in (a) vinyl chloride resin is at or below the aforementioned upper limit, the physical strength of the vinyl chloride resin molded article formed using the vinyl chloride resin composition for powder molding can be further improved.

[0067] <(b) Plasticizers>

[0068] (b) The plasticizer comprises at least one of (b1) trimellitate and (b2) polyester. If the plasticizer (b) used as the powder molding vinyl chloride resin composition of the present invention comprises at least one of (b1) trimellitate and (b2) polyester, a vinyl chloride resin molded body with sufficiently excellent tensile properties (especially tensile elongation) can be formed.

[0069] In addition, (b) the plasticizer may include other plasticizers besides (b1) trimellitate and (b2) polyester.

[0070] <<(b1) Trimethicone>>

[0071] (b) The trimellitate contained in the plasticizer is preferably an ester compound of trimellitic acid and a monohydric alcohol.

[0072] Specific examples of the aforementioned monohydric alcohols are not particularly limited, and include aliphatic alcohols such as 1-hexanol, 1-heptanol, 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, and 1-dodecanol. Aliphatic alcohols with 6 to 18 carbon atoms are particularly preferred as monohydric alcohols, and straight-chain aliphatic alcohols with 6 to 18 carbon atoms are more preferred.

[0073] As the aforementioned (b1) trimellitic acid ester, a trimellitic acid ...

[0074] The aforementioned (b1) trimellitic acid ester can be formed from a single compound or a mixture of different compounds.

[0075] Suitable examples of trimellitic esters include trihexyl trimellitate, triheptyl trimellitate, trioctyl trimellitate, tri(2-ethylhexyl) trimellitate, trinonyl trimellitate, tridecyl trimellitate, triisodecyl trimellitate, triundecyl trimellitate, tridodecyl trimellitate, trialkyl trimellitate (esters having two or more alkyl groups with different numbers of carbon atoms [wherein the number of carbon atoms is 6 to 18]), trialkyl trimellitate (esters having two or more alkyl groups with different numbers of carbon atoms [wherein the number of carbon atoms is 6 to 18]), and mixtures thereof.

[0076] More preferred (b1) examples of trimellitic esters include trioctyl trimellitate, tri(2-ethylhexyl) trimellitate, trinonyl trimellitate, tridecyl trimellitate, trialkyl trimellitate (esters having two or more alkyl groups with different numbers of carbon atoms [wherein the number of carbon atoms is 6 to 18]) and mixtures thereof.

[0077] (b) The content of trimellitate (b1) in the plasticizer can be 0% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and can be 100% by mass or less, preferably 65% ​​by mass or less, more preferably 55% by mass or less, even more preferably 45% by mass or less. If the content of trimellitate (b1) in the plasticizer is within the above-specified range, the tensile properties (especially elongation) of the formed vinyl chloride resin molded article can be further improved.

[0078] Furthermore, the content of trimellitate (b1) in the vinyl chloride resin composition for powder molding is preferably 0 parts by mass or more, more preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, preferably 100 parts by mass or less, more preferably 65 parts by mass or less, even more preferably 55 parts by mass or less, and even more preferably 45 parts by mass or less, relative to 100 parts by mass. If the content of trimellitate (b) in the vinyl chloride resin composition for powder molding is within the above-specified range, the tensile properties (especially elongation at break) of the formed vinyl chloride resin molded article can be further improved. Furthermore, if the content of trimellitate (b) in the vinyl chloride resin composition for powder molding is below the above-specified upper limit, the micropores on the surface of the formed vinyl chloride resin molded article can be sufficiently reduced.

[0079] <<(b2) Polyester>>

[0080] The polyester included in (b) plasticizer (b2) is not particularly limited, and polyesters such as those containing structural units from adipic acid (adipic acid-based polyesters), those containing structural units from sebacic acid (sebacic acid-based polyesters), and those containing structural units from phthalic acid (phthalic acid-based polyesters) can be used. Furthermore, these polyesters can be used alone or in mixtures of two or more in any ratio.

[0081] Furthermore, the polyester included as (b) plasticizer is not particularly limited, and polyesters containing, for example, structural units from diol compounds such as 3-methyl-1,5-pentanediol and 1,3-butanediol can be used.

[0082] Furthermore, from the viewpoint of further improving the tensile properties (especially the elongation at break) of the formed vinyl chloride resin molded body, as (b2) polyester, it is preferable to use a polyester containing structural units derived from bisacrylic acid, more preferably a polyester containing structural units derived from bisacrylic acid and structural units derived from diol compounds, and particularly preferably a polyester containing structural units derived from bisacrylic acid and structural units derived from 3-methyl-1,5-pentanediol.

[0083] For ease of explanation, polyesters containing structural units from dioxic acid and structural units from 3-methyl-1,5-pentanediol will be referred to as "polyester A".

[0084] Here, polyester A containing the structural units specified above may have structural units other than those derived from ascorbic acid and those derived from 3-methyl-1,5-pentanediol. The total percentage of the structural units derived from ascorbic acid and those derived from 3-methyl-1,5-pentanediol is preferably 50% by mass or more, more preferably 80% by mass or more, of all structural units. Furthermore, polyester A containing the structural units specified above preferably has only the structural units derived from ascorbic acid and those derived from 3-methyl-1,5-pentanediol as repeating units.

[0085] Furthermore, polyester A containing the aforementioned structural units can be obtained without particular limitation by polycondensation of adipic acid and 3-methyl-1,5-pentanediol. Additionally, the polycondensation can be carried out in the presence of a catalyst. Furthermore, the polycondensation can be carried out using alcohols and / or monocarboxylic acids as terminating agents. Moreover, the polycondensation of adipic acid and 3-methyl-1,5-pentanediol, and the termination reaction of the resulting polycondensate with the aforementioned terminating agent can be carried out simultaneously or separately. Furthermore, the product obtained after polycondensation and the termination reaction can be subjected to post-treatment such as distillation. Moreover, known conditions can be used for the polycondensation reaction conditions, such as the amount of monomer, catalyst, and terminating agent used.

[0086] In addition, commercially available products can be used as polyester A, which contains the structural units specified above.

[0087] There are no particular limitations on the catalysts used in polycondensation reactions; examples include dibutyltin oxide and tetraalkyl titanates.

[0088] In addition, examples of alcohols that can be used as terminal terminating components include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, hexanol, isohexanol, heptanol, isoheptanol, octanol, isooctanol, 2-ethylhexanol, nonanol, isononol, decanol, isodecanol, undecyl alcohol, isoundecyl alcohol, dodecyl alcohol, tridecyl alcohol, isotridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecanol, octadecyl alcohol, cellosol, carbitol, phenol, nonylphenol, benzyl alcohol, and mixtures thereof.

[0089] Furthermore, examples of monocarboxylic acids that can be used as terminal terminating components include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, neovaleric acid, hexanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, benzoic acid, and mixtures thereof.

[0090] 2-Ethylhexanol is particularly preferred as the terminal terminating component.

[0091] Furthermore, the number average molecular weight of the polyester A containing the structural units specified above is preferably 1,000 or more, more preferably 2,000 or more, more preferably 10,000 or less, and more preferably 7,000 or less.

[0092] In addition, the number-average molecular weight can be determined using the VPO (vapor pressure osmotic pressure) method.

[0093] Furthermore, the acid value of polyester A containing the structural units specified above is preferably below 1 mg KOH / g.

[0094] Furthermore, the hydroxyl value of polyester A containing the structural units specified above is preferably 30 mg KOH / g or less.

[0095] Furthermore, the viscosity of polyester A containing the structural units specified above is preferably 500 mPa·s or more, more preferably 1000 mPa·s or more, more preferably 8000 mPa·s or less, and more preferably 5000 mPa·s or less.

[0096] In addition, the viscosity can be measured at 23°C according to JIS Z8803.

[0097] (b) The content of (b2) polyester in the plasticizer can be 0% by mass or more, preferably 35% by mass or more, more preferably 45% by mass or more, even more preferably 55% by mass or more, and can be 100% by mass or less, preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less. If the content of (b2) polyester in the plasticizer is within the above-specified range, the tensile properties (especially elongation) of the formed vinyl chloride resin molded article can be further improved.

[0098] Furthermore, the content of (b2) polyester in the vinyl chloride resin composition for powder molding can be 0 parts by mass or more relative to 100 parts by mass of the aforementioned (a) vinyl chloride resin, preferably 20 parts by mass or more, more preferably 35 parts by mass or more, further preferably 45 parts by mass or more, even more preferably 55 parts by mass or more, preferably 100 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 85 parts by mass or less, and even more preferably 80 parts by mass or less. If the content of (b2) polyester in the vinyl chloride resin composition for powder molding is within the above-specified range, the tensile properties (especially elongation at break) of the vinyl chloride resin molded article can be further improved. In addition, if the content of (b2) polyester in the vinyl chloride resin composition for powder molding is below the above-specified upper limit, the micropores on the surface of the formed vinyl chloride resin molded article can be sufficiently reduced.

[0099] Furthermore, the total content of (b1) trimellitate and (b2) polyester in the vinyl chloride resin composition for powder molding is preferably 30 parts by mass or more, more preferably 45 parts by mass or more, further preferably 65 parts by mass or more, even more preferably 80 parts by mass or more, even more preferably 90 parts by mass or more, preferably 200 parts by mass or less, more preferably 155 parts by mass or less, even more preferably 140 parts by mass or less, and even more preferably 125 parts by mass or less. If the total content of (b1) trimellitate and (b2) polyester in the vinyl chloride resin composition for powder molding is within the above-specified range, the tensile properties (especially elongation at break) of the formed vinyl chloride resin molded article can be further improved. In addition, if the total content of (b1) trimellitate and (b2) polyester in the vinyl chloride resin composition for powder molding is below the above-specified upper limit, the micropores on the surface of the formed vinyl chloride resin molded article can be sufficiently reduced.

[0100] Furthermore, the mass ratio (triptyl phthalate / polyester) of (b1) trimellitate to (b2) polyester in the vinyl chloride resin composition for powder molding is preferably 1 / 9 or more, more preferably 1 / 4 or more, even more preferably 1 / 3 or more, preferably 9 / 1, more preferably 2 / 1 or less, even more preferably 1 / 1 or less, and even more preferably 2 / 3 or less. If the mass ratio (triptyl phthalate / polyester) of (b1) trimellitate to (b2) polyester in the vinyl chloride resin composition for powder molding is within the above-specified range, the tensile properties (especially elongation) of the formed vinyl chloride resin molded article can be further improved.

[0101] <<(b3) Other Plasticizers>>

[0102] The plasticizer contained in the vinyl chloride resin composition for powder molding may optionally include plasticizers other than the trimellitate and polyester described above (sometimes referred to as "(b3) other plasticizers").

[0103] As specific examples of other plasticizers (b3), examples include primary plasticizers other than trimellitate (b1) and polyester (b2) described in International Publication No. 2016 / 098344, as well as auxiliary plasticizers.

[0104] From the viewpoint of further improving the tensile properties (especially elongation) of the formed vinyl chloride resin molded articles, epoxidized vegetable oil is particularly preferred, and epoxidized soybean oil is even more preferred.

[0105] (b) The content of the other plasticizers mentioned in (b3) in the plasticizer is not particularly limited, but is preferably 0% by mass or more and 5% by mass or less. If the content of the other plasticizers mentioned in (b3) in the plasticizer is within the above range, the tensile properties (especially the elongation at break) of the formed vinyl chloride resin molded article can be further improved.

[0106] Furthermore, the content of the other plasticizers in the vinyl chloride resin composition for powder molding is not particularly limited, and can be 0 parts by mass or more and 5 parts by mass or less relative to 100 parts by mass of the vinyl chloride resin in (a) above.

[0107] Furthermore, the total content of the aforementioned (b1) trimellitate, (b2) polyester, and (b3) other plasticizers in the vinyl chloride resin composition for powder molding (i.e., the content of (b) plasticizer) relative to 100 parts by weight of the aforementioned (a) vinyl chloride resin is preferably 30 parts by weight or more, more preferably 45 parts by weight or more, even more preferably 65 parts by weight or more, even more preferably 80 parts by weight or more, even more preferably 90 parts by weight or more, preferably 200 parts by weight or less, more preferably 155 parts by weight or less, even more preferably 140 parts by weight or less, and even more preferably 125 parts by weight or less. If the content of (b) plasticizer in the vinyl chloride resin composition for powder molding is within the aforementioned specified range, the tensile properties (especially elongation at break) of the formed vinyl chloride resin molded article can be further improved. In addition, if the content of (b) plasticizer in the vinyl chloride resin composition for powder molding is below the aforementioned upper limit, the micropores on the surface of the formed vinyl chloride resin molded article can be sufficiently reduced.

[0108] <Acrylic polymers>

[0109] In vinyl chloride resin compositions for powder molding, (c) acrylic polymers typically function as release agents. The vinyl chloride resin compositions for powder molding of the present invention, containing (c) acrylic polymers, can reduce the micropores on the surface of the formed vinyl chloride resin molded articles.

[0110] In this specification, "acrylic polymer" refers to a polymer containing structural units derived from alkyl esters of (meth)acrylate. Additionally, in this specification, "(meth)acrylic acid" refers to acrylic acid and / or methacrylic acid.

[0111] As an acrylic polymer, a polymer containing only structural units from (meth)acrylate (i.e., a homopolymer of (meth)acrylate) can be used, or a polymer containing structural units from (meth)acrylate and structural units from compounds other than (meth)acrylate (i.e., a copolymer of (meth)acrylate and other compounds) can be used.

[0112] Moreover, acrylic polymers can be prepared by polymerizing alkyl (meth)acrylates with other compounds as needed using conventional methods.

[0113] Alkyl methacrylates that can be used in the preparation of acrylic polymers are not particularly limited, and examples include butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, and decyl methacrylate. Octyl methacrylate is particularly preferred as an alkyl methacrylate, 2-ethylhexyl methacrylate is more preferred, and 2-ethylhexyl acrylate (2-ethylhexyl acrylate) is especially preferred.

[0114] Furthermore, there are no particular limitations on other compounds that can be used in preparing copolymers of (meth)acrylates and other compounds as acrylic polymers, as long as they are compounds other than vinyl chloride that can copolymerize with (meth)acrylates.

[0115] The proportion of structural units derived from (meth)acrylates in the acrylic polymer is not particularly limited, but is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 100% by mass or more. That is, it is particularly preferred that the acrylic polymer is a homopolymer of (meth)acrylates.

[0116] Furthermore, the weight-average molecular weight of the acrylic polymer needs to be 1000 or more, preferably 1500 or more, more preferably 2000 or more, even more preferably 2500 or more, particularly preferably 5000 or more, preferably 50000 or less, preferably 30000 or less, more preferably 20000 or less, even more preferably 10000 or less, and particularly preferably 6000 or less. If the weight-average molecular weight of the acrylic polymer is within the above-specified range, the micropores on the surface of the formed vinyl chloride resin molded article can be reduced.

[0117] The content of the acrylic polymer (c) in the vinyl chloride resin composition for powder molding is preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, even more preferably 0.15 parts by weight or more, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, even more preferably 1 part by weight or less, and particularly preferably 0.4 parts by weight or less, relative to 100 parts by weight of the aforementioned vinyl chloride resin. If the content of the acrylic polymer (c) in the vinyl chloride resin composition for powder molding is within the above-specified range, the micropores on the surface of the formed vinyl chloride resin molded article can be further reduced.

[0118] <Additives>

[0119] In addition to the above-mentioned components, the vinyl chloride resin composition for powder molding of the present invention may also contain various additives. As additives, there are no particular limitations, but examples include: components that can function as plasticizers other than (b) trimellitate and (c) polyesters containing specified structural units (other plasticizers); lubricants; stabilizers such as perchloric acid-treated hydrotalcite, zeolite, β-diketone, and fatty acid metal salts; release agents; release agents other than the above-mentioned vinyl chloride resin particles; impact resistance modifiers; perchloric acid compounds other than perchloric acid-treated hydrotalcite (sodium perchlorate, potassium perchlorate, etc.); antioxidants; mildew inhibitors; flame retardants; antistatic agents; fillers; light stabilizers; foaming agents; pigments, etc.

[0120] Furthermore, the additives that may be included in the vinyl chloride resin composition for powder molding of the present invention can be, for example, those described in International Publication No. 2016 / 098344, and their preferred content can also be the same as that described in International Publication No. 2016 / 098344.

[0121] Furthermore, from the viewpoint of further reducing the micropores on the surface of the formed vinyl chloride resin molded body, the vinyl chloride resin composition for powder molding of the present invention preferably does not contain a foaming agent.

[0122] Specific examples of foaming agents include: azo compounds such as azodicarbonamide and azobisisobutyronitrile; nitroso compounds such as N,N'-dinitrospentamethylenetetramine; sulfonyl hydrazide compounds such as p-toluenesulfonyl hydrazide and p,p-oxobis(benzenesulfonyl hydrazide); volatile hydrocarbon compounds such as Freon gas, carbon dioxide, water, and pentane; and foaming agents for gaseous systems such as microcapsules containing these compounds.

[0123] Furthermore, the vinyl chloride resin composition for powder molding of the present invention preferably contains 12-hydroxystearic acid. If the above-mentioned (c) acrylic polymer and 12-hydroxystearic acid are used together, the micropores on the surface of the formed vinyl chloride resin molded article can be further reduced.

[0124] The content of 12-hydroxystearic acid in the vinyl chloride resin composition for powder molding is preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, even more preferably 0.15 parts by weight or more, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, even more preferably 1 part by weight or less, and particularly preferably 0.4 parts by weight or less, relative to 100 parts by weight of the vinyl chloride resin composition for powder molding. If the content of 12-hydroxystearic acid in the vinyl chloride resin composition for powder molding is within the above-specified range, the micropores on the surface of the formed vinyl chloride resin molded article can be further reduced.

[0125] Furthermore, the vinyl chloride resin composition for powder molding of the present invention may contain silicone oil.

[0126] In addition, silicone oils that can be included in the vinyl chloride resin composition for powder molding include, for example, the silicone oil described in Japanese Patent Application Publication No. 2018-35304.

[0127] Furthermore, the content of silicone oil in the vinyl chloride resin composition for powder molding is not particularly limited, but is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, more preferably 1 part by mass or less, and more preferably 0.8 parts by mass or less, relative to 100 parts by mass of the above-mentioned (a) vinyl chloride resin.

[0128] <Preparation Method of Vinyl Chloride Resin Composition for Powder Molding>

[0129] The vinyl chloride resin composition for powder molding of the present invention can be prepared by mixing the above-mentioned components.

[0130] Here, the mixing method for (a) vinyl chloride resin, (b) plasticizer, (c) acrylic polymer, and various additives further formulated as needed is not particularly limited. Examples include methods such as dry mixing of the components except for the release agent (containing vinyl chloride resin particles), followed by adding and mixing the release agent. Here, a Henschel mixer is preferably used for dry mixing. Furthermore, the temperature during dry mixing is not particularly limited, but is preferably 50°C or higher, more preferably 70°C or higher, and most preferably 200°C or lower.

[0131] <Applications of vinyl chloride resin compositions for powder molding>

[0132] Furthermore, the obtained vinyl chloride resin composition for powder molding can be used for powder molding and is suitable for powder slush molding.

[0133] (vinyl chloride resin molded body)

[0134] The vinyl chloride resin molded article of the present invention is characterized in that it is obtained by powder molding the above-mentioned vinyl chloride resin composition for powder molding using any powder molding method. Moreover, since the vinyl chloride resin molded article of the present invention is formed using the above-mentioned vinyl chloride resin composition for powder molding, it generally contains at least (a) vinyl chloride resin, (b) plasticizer and (c) acrylic polymer and has few micropores.

[0135] Therefore, the vinyl chloride resin molded articles of the present invention are suitable for use in manufacturing the skins of automotive interior parts such as dashboards and door trims, which have fewer micropores and excellent appearance.

[0136] In addition, in this invention, "micropore" refers to a recess observed on the surface of a vinyl chloride resin molded body, wherein the equivalent diameter of the circle (equivalent area equivalent diameter of the circle) is 100 μm or more and 200 μm or less.

[0137] Furthermore, on the surface of the vinyl chloride resin molded article of the present invention, the number of micropores observed in an area with dimensions of 2 cm x 2 cm is preferably 150 or less, more preferably 120 or less, and even more preferably 100 or less. If the number of micropores on the surface of the vinyl chloride resin molded article is less than or equal to the above-mentioned specified value, the appearance of the vinyl chloride resin molded article can be improved. In addition, the number of micropores observed on the surface of the vinyl chloride resin molded article of the present invention in an area with dimensions of 2 cm x 2 cm is not particularly limited, and is generally 10 or more.

[0138] In addition, the number of micropores on the surface of the vinyl chloride resin molded body can be determined by the method described in the examples of this specification.

[0139] <Method for forming vinyl chloride resin molded articles>

[0140] Here, when forming a vinyl chloride resin molded body by powder slush molding, there is no particular limitation on the mold temperature during powder slush molding, but it is preferably 200°C or higher, more preferably 220°C or higher, more preferably 300°C or lower, and more preferably 280°C or lower.

[0141] Furthermore, there are no particular limitations in manufacturing the vinyl chloride resin molded body; for example, the following method can be used: The vinyl chloride resin composition for powder molding of the present invention is sprinkled into a mold within the aforementioned temperature range, and after being left for 5 seconds to 30 seconds, the remaining vinyl chloride resin composition for powder molding is shaken off. Then, it is left at any temperature for 30 seconds to 3 minutes. Afterward, the mold is cooled to 10°C to 60°C, and the obtained vinyl chloride resin molded body of the present invention is demolded from the mold. Then, a sheet-like molded body resembling the shape of the mold is obtained.

[0142] (Layered structure)

[0143] The laminate of the present invention comprises a foamed polyurethane molded body and the aforementioned vinyl chloride resin molded body. Furthermore, the vinyl chloride resin molded body typically forms one surface of the laminate.

[0144] Furthermore, the laminate of the present invention has an excellent appearance because it is a vinyl chloride resin molded body with few pores, for example, formed using the vinyl chloride resin composition for powder molding of the present invention. Therefore, the laminate of the present invention is suitable for use as an automotive interior material, for example, forming automotive interior parts such as dashboards and door trims.

[0145] Here, the lamination method of the polyurethane foam and the vinyl chloride resin molded body is not particularly limited, and the following methods can be used, for example: (1) after preparing the polyurethane foam and the vinyl chloride resin molded body separately, a method of bonding them together using hot melt welding, hot bonding, or a known adhesive; (2) a method of reacting isocyanates and polyols, which are raw materials for the polyurethane foam, on the vinyl chloride resin molded body to polymerize them, and foaming the polyurethane using a known method, thereby directly forming the polyurethane foam on the vinyl chloride resin molded body. From the perspective of simplifying the process and from the viewpoint that it is easy to firmly bond the vinyl chloride resin molded body and the polyurethane foam in the case of obtaining laminates of various shapes, the latter method (2) is particularly preferred.

[0146] Example

[0147] The present invention will now be specifically described based on embodiments, but the present invention is not limited to these embodiments. Furthermore, in the following description, unless otherwise specified, "%" and "parts" refer to quantities based on mass.

[0148] Furthermore, the tensile elongation and pinholes of the vinyl chloride resin molded articles were determined and evaluated using the following methods.

[0149] <Elongation at break>

[0150] Vinyl chloride resin molded sheets were punched using the No. 1 dumbbell cutter described in JIS K6251. The tensile elongation at break (%) was measured at room temperature (23°C) and low temperature (-10°C) conditions at a tensile speed of 200 mm / min, according to JIS K7113. Furthermore, a higher value of tensile elongation at break indicates better tensile elongation of the vinyl chloride resin molded sheet.

[0151] <Micropores>

[0152] The number of micropores on the surface of the obtained vinyl chloride resin molded sheet was determined as follows.

[0153] Specifically, a digital microscope (Keyence, product name "VHX-6000") was used at 50x magnification, with the field of view connected. An area measuring 2cm x 2cm was defined as the measurement area. Within this area, recesses with a circular equivalent diameter (equivalent area circular equivalent diameter) of 100μm or more but less than 200μm were counted as micropores, and their total number was determined. The fewer the number of micropores, the smoother and more uniform the surface of the vinyl chloride resin molded sheet, resulting in a superior appearance.

[0154] (Manufacturing example)

[0155] The polyester and acrylic polymers used in the examples and comparative examples were prepared as described below.

[0156] <Polyester A>

[0157] Adipic acid (a polycarboxylic acid), 3-methyl-1,5-pentanediol (a polyol), and 2-ethylhexanol (a terminator / terminant) were added to a reaction vessel. Tetraisopropyl titanate (a catalyst) was added, along with an appropriate amount of solvent. The mixture was stirred and heated. Concurrent water was removed under normal and reduced pressure. Finally, the temperature was raised to 220–230 °C to terminate the dehydration condensation reaction. Polyester A (viscosity: 3600 mPa·s, number-average molecular weight: 5300, acid value: 0.32, hydroxyl value: 14.5) was obtained, terminated by a 2-ethylhexyloxy group.

[0158] <Acrylic polymer (homogeneous polymer of 2-ethylhexyl acrylate)>

[0159] By polymerizing 2-ethylhexyl acrylate using conventional methods, a homopolymer of 2-ethylhexyl acrylate (weight average molecular weight: 5227) was obtained as an acrylic polymer.

[0160] (Example 1)

[0161] <Preparation of Vinyl Chloride Resin Compositions for Powder Molding>

[0162] All components of the formulation shown in Table 1, except for the plasticizers (trimethoate, polyester A, and epoxidized soybean oil) and the vinyl chloride resin microparticles as a release agent, were added to a Henschel mixer and mixed. Then, when the temperature of the mixture reached 80°C, all of the aforementioned plasticizer was added, thereby allowing it to dry completely (meaning the plasticizer was absorbed by the vinyl chloride resin particles, resulting in a dry mixture). Then, when the temperature of the dried mixture cooled to below 70°C, the vinyl chloride resin microparticles as a release agent were added to prepare a vinyl chloride resin composition for powder molding.

[0163] <Formation of Vinyl Chloride Resin Molded Components>

[0164] A vinyl chloride resin molded sheet with dimensions of 145mm × 175mm × 1mm is produced as described below.

[0165] Specifically, the obtained vinyl chloride resin composition for powder molding is sprinkled into a textured mold heated to 250°C. After melting for an arbitrary period of time, the remaining vinyl chloride resin composition for powder molding is shaken off. Then, the textured mold containing the vinyl chloride resin composition for powder molding is placed in an oven set to 200°C and left to stand. After 60 seconds of standing, the textured mold is cooled with cooling water. When the temperature of the mold cools to 40°C, the vinyl chloride resin molded sheet, which is the vinyl chloride resin molded body, is demolded from the mold.

[0166] Then, for the obtained vinyl chloride resin molded sheets (size: 145mm × 175mm × 1mm), the tensile elongation and micropores were measured and evaluated according to the method described above. The results are shown in Table 1.

[0167] (Example 2)

[0168] The amount of acrylic polymer used was varied as shown in Table 1. Otherwise, the process was the same as in Example 1 to prepare polyester A, a vinyl chloride resin composition for powder molding, and a vinyl chloride resin molded body. Then, the measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0169] (Example 3)

[0170] Using the amounts of 12-hydroxystearic acid shown in Table 1, except as in Example 1, polyester A, a vinyl chloride resin composition for powder molding, and a vinyl chloride resin molded body were prepared. Then, measurements and evaluations were performed as in Example 1. The results are shown in Table 1.

[0171] (Example 4)

[0172] As shown in Table 1, trimellitate as a plasticizer was omitted, and the amount of polyester A was increased. Otherwise, the same procedure as in Example 2 was followed to prepare polyester A, a vinyl chloride resin composition for powder molding, and a vinyl chloride resin molded body. Then, the measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0173] (Example 5)

[0174] As shown in Table 1, the type of vinyl chloride resin particles was changed, and the amount of vinyl chloride resin microparticles as a separating agent and the amount of trimellitate and polyester A as plasticizers were reduced. Otherwise, the process was the same as in Example 2, producing polyester A, a vinyl chloride resin composition for powder molding, and a vinyl chloride resin molded body. Then, the measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0175] (Comparative Example 1)

[0176] Without using acrylic polymers, the same procedures as in Example 3 were followed to prepare polyester A, a vinyl chloride resin composition for powder molding, and a vinyl chloride resin molded body. Then, the measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0177] (Comparative Example 2)

[0178] Without using acrylic polymers, the same procedures as in Example 1 were followed to prepare polyester A, a vinyl chloride resin composition for powder molding, and a vinyl chloride resin molded body. Then, the measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0179] [Table 1]

[0180]

[0181] 1) Manufactured by Shinichi Chloride Co., Ltd., product name "ZEST (registered trademark) 1700ZI" (prepared by suspension polymerization, average degree of polymerization: 1700, average particle size: 129μm).

[0182] 2) Manufactured by Shinichi Chloride Co., Ltd., product name "ZEST (registered trademark) 1300SI" (prepared by suspension polymerization, average degree of polymerization: 1300, average particle size: 132μm).

[0183] 3) Manufactured by Shinichi Chloride Co., Ltd., product name "ZEST PQLTX" (prepared by emulsion polymerization, average degree of polymerization: 800, average particle size: 1.8μm)

[0184] 4) Manufactured by Kao Corporation, product name "Trimex N-08"

[0185] 5) Manufactured by ADK Corporation, product name "ADK CIZER O-130S"

[0186] 6) Manufactured by Kyowa Chemical Industry Co., Ltd., product name "ALCAMAIZER (registered trademark) 5"

[0187] 7) Manufactured by Mizusawa Chemical Industry Co., Ltd., product name "MIZUKALIZER DS"

[0188] 8) Manufactured by Showa Denko Co., Ltd., product name "Karenz DK-1"

[0189] 9) Sakai Chemical Industry Co., Ltd., product name "SAKAI SZ2000"

[0190] 10) Manufactured by ADK STAB Co., Ltd., product name "ADK STAB LS-12"

[0191] 11) Manufactured by Shin-Etsu Silicone Co., Ltd., product name "KF-96H-300,000 cs" (unmodified silicone oil (polydimethylsiloxane), viscosity: 30×10⁴ cs)

[0192] 12) Manufactured by Daihatsu Seika Co., Ltd., product name "DA PX 1720(A)BLACK"

[0193] As shown in Table 1, the vinyl chloride resin compositions for powder molding of Examples 1 to 5, which contain vinyl chloride resin, a specified plasticizer, and an acrylic polymer with a weight-average molecular weight within a specified range, can yield vinyl chloride resin molded articles with fewer micropores.

[0194] Furthermore, as shown in Table 1, when the vinyl chloride resin compositions for powder molding of Comparative Examples 1 and 2, which do not contain acrylic polymers with a weight-average molecular weight within the specified range, are used, the surface of the formed vinyl chloride resin molded articles has more micropores.

[0195] Industrial availability

[0196] According to the present invention, a vinyl chloride resin composition for powder molding capable of forming vinyl chloride resin molded articles with few micropores can be provided.

[0197] Furthermore, according to the present invention, vinyl chloride resin molded articles with fewer micropores can be provided.

[0198] Furthermore, according to the present invention, it is possible to provide a laminate having the vinyl chloride resin molded body.

Claims

1. A vinyl chloride resin composition for powder molding, comprising: Vinyl chloride resin, Plasticizers containing at least one of trimellitate and polyester, and Acrylic polymers with a weight-average molecular weight of 5000 or higher but less than 6000. The content of the acrylic polymer is 0.05 parts by weight or more and 10 parts by weight or less relative to 100 parts by weight of the vinyl chloride resin. The total content of the trimellitate and the polyester is 30 parts by weight or more and 200 parts by weight or less relative to 100 parts by weight of the vinyl chloride resin. The acrylic polymer contains structural units derived from 2-ethylhexyl acrylate.

2. The vinyl chloride resin composition for powder molding according to claim 1, wherein, The vinyl chloride resin composition for powder molding is used for powder slush molding.

3. A vinyl chloride resin molded body, which is formed by powder molding of the vinyl chloride resin composition for powder molding as described in claim 1 or 2.

4. The vinyl chloride resin molded article according to claim 3, wherein, The vinyl chloride resin molded body is used for the surface layer of automotive interior parts.

5. A laminate comprising a foamed polyurethane molded body and a vinyl chloride resin molded body as described in claim 3.

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