Plastisol composition

Abstract

Provided are: a plastisol composition having excellent storage stability, excellent processability and mechanical properties under low-temperature processing at about 80°C, and excellent characteristics as a coating agent, especially for automobile underbody coats and automobile sealants; and a use for the plastisol composition.　The plastisol composition includes at least a vinyl chloride-vinyl acetate copolymer (A) having an average vinyl acetate polymerization unit content of 5-20 wt%, a compound (B) meeting the criteria of (1) a viscosity of 4000-500,000 mPa∙s and (2) a solubility parameter of 16-22 (J / cm3)1 / 2, and a compound (C) meeting the criteria of (3) a weight-average molecular weight of 300-2000. The total amount of the compound (B) and the compound (C) per 100 weight parts of the vinyl chloride-vinyl acetate copolymer (A) is 80-250 weight parts, and the proportion of the compound (C) to the total amount of the compound (B) and the compound (C) is 10-60 wt%.

Description

Plastisol composition

[0001] The present invention relates to a plastisol composition. More specifically, by comprising a combination of compounds having at least specific properties for a specific vinyl chloride-vinyl acetate copolymer, preferably a combination of a specific epoxy resin and a specific compound, the plastisol composition is suitably applicable to low-temperature processing at about 80°C, and is useful as a coating agent, particularly for automotive underbody coatings and automotive sealants suitable for low-temperature processing, and relates to uses thereof.

[0002] From the perspective of reducing environmental impact, measures to reduce carbon dioxide emissions and save energy are being promoted in the automotive underbody coating and automotive sealant painting processes. As part of these efforts, there is a demand to reduce carbon dioxide emissions generated by energy consumption in the baking and drying ovens in the painting process, and lowering the temperature of baking and drying ovens is required to achieve energy savings and carbon dioxide emission reduction. However, simply adopting low-temperature processing makes it difficult to achieve the inherent functions and performances such as mechanical properties of the molded product, which is not practical. Therefore, the emergence of materials, coating agents, and coating materials suitable for low-temperature processing is expected.

[0003] Vinyl chloride-based resins for paste processing (hereinafter sometimes referred to as paste vinyl chloride) are generally kneaded with plasticizers, fillers, stabilizers or other compounding agents to prepare plastisol compositions, which can be molded and formed into films by solidification (gelation) under heating (usually about 180 to 200°C), and are widely used for automotive underbody coatings and automotive sealants. A vinyl chloride / vinyl acetate copolymer resin has been proposed as a paste vinyl chloride resin that can be gelled and melted at a relatively low temperature of about 140°C and has excellent mechanical strength (see, for example, Patent Document 1). Further, as a plastisol composition that can obtain mechanical strength at a processing temperature of 100 to 120°C, a composition obtained by blending a vinyl chloride-vinyl acetate copolymer resin and a (meth)acrylic resin and incorporating a blocked isocyanate as an adhesion agent has been proposed (see, for example, Patent Document 2).

[0004] JP 2018-76477 A JP 2021-11525 A

[0005] However, in recent years, the demand for reducing energy consumption in manufacturing processes in the industrial sector, particularly the automotive industry, has become even higher. Raw materials, coating agents, and covering agents that can be processed at lower temperatures, particularly 80°C or lower, are required. Even in the proposals of Patent Documents 1 and 2, processability at a baking temperature below 100°C, mechanical properties and the like have not been studied at all, making it difficult to meet this demand. In addition, long-term storage stability after plastisol preparation is required for these applications, and a plastisol with little change in sol viscosity over time is demanded.

[0006] Note that low-temperature materials and technologies during molding processing contribute to the reduction of carbon dioxide emissions and energy conservation, contribute to the promotion of inclusive and sustainable industries, and are expected as one of the basic technologies necessary for a sustainable society such as the SDGs.

[0007] Accordingly, the present invention aims to provide a plastisol composition that is excellent in storage stability, processability during low-temperature (more specifically, 80°C) processing, and mechanical properties, and has excellent properties as a coating agent, particularly for automotive underbody coating and automotive sealant, as well as uses thereof.

[0008] As a result of extensive and intensive studies on the above problems, the present inventors have found that a plastisol composition containing a vinyl chloride-vinyl acetate copolymer having a specific vinyl acetate polymerization unit content, a compound having a specific viscosity and solubility parameter, and a compound having a specific molecular weight in a specific ratio is excellent in storage stability, processability during low-temperature (specifically 70 to 90°C, preferably 75 to 85°C, particularly 80°C) processing, mechanical strength and elongation, and have completed the present invention.

[0009] That is, the present invention resides in the following [1] to

[13] .

[0010] [1] A plastisol composition comprising at least a vinyl chloride-vinyl acetate copolymer (A) having an average content of vinyl acetate polymerization units of 5 to 20% by weight, a compound (B) satisfying the following (1) and (2), and a compound (C) satisfying the following (3), wherein the total amount of compound (B) and compound (C) is 80 to 250 parts by weight per 100 parts by weight of the vinyl chloride-vinyl acetate copolymer (A), and the ratio of compound (C) to the total amount of compound (B) and compound (C) is 10 to 60% by weight. (1); 23°C, shear rate 4s －１ Viscoelasticity measured under the following conditions: (2) Viscosity of 4,000 to 500,000 mPa·s; Hasnsen solubility parameter of 16 to 22 (J / cm²). ３ ) １／２ (3) Weight-average molecular weight is 300 to 2000 [2] The plastisol composition according to [1], characterized in that the vinyl chloride-vinyl acetate copolymer (A) is a vinyl chloride-vinyl acetate copolymer containing primary particle sizes of volume-based median diameter of 0.5 to 30 μm. [3] The plastisol composition according to [1] or [2], characterized in that the compound (B) is one or more compounds selected from the group consisting of aromatic epoxy resins (B1), alicyclic epoxy resins (B2), and polyester compounds (B3). [4] The plastisol composition according to any one of [1] to [3], characterized in that the compound (C) is at least one compound selected from the group consisting of compounds having an aromatic ring and an aliphatic hydrocarbon group (C1), aliphatic ester compounds (C2), aliphatic oligomers (C3), all-aliphatic epoxy compounds (C4), and silicon oligomers (C5).

[0011] [5] The plastisol composition according to any one of [1] to [4], characterized in that it is for low-temperature processing at a molding temperature of 70 to 90°C. [6] The plastisol composition according to any one of [1] to [5], characterized in that a JIS No. 3 dumbbell test piece prepared from a 2 mm thick sheet under heating conditions of 80°C for 30 minutes has a tensile strength of 0.5 MPa or more and a tensile elongation of 50% or more in accordance with JIS K6251. [7] The plastisol composition according to any one of [1] to [6], characterized in that compound (B) is an aromatic epoxy resin (B1), and compound (C) is a compound (C1) having an aromatic ring and an aliphatic hydrocarbon group. [8] The plastisol composition according to [7], characterized in that the aromatic epoxy resin (B1) is a bisphenol A type epoxy resin. [9] The plastisol composition according to [7] or [8], characterized in that the compound (C1) having an aromatic ring and an aliphatic hydrocarbon group is one or more compounds selected from the group consisting of phthalates, trimellitic acid esters, pyromellitic acid esters and phenyl sulfonates.

[10] The plastisol composition according to any one of [7] to [9], characterized in that a JIS No. 3 dumbbell test piece prepared from a 2 mm thick sheet under heating conditions of 80°C for 30 minutes has a tensile strength of 0.5 MPa or more and a tensile elongation of 60% or more in accordance with JIS K6251.

[11] The plastisol composition according to any one of [1] to

[10] , further characterized in that it contains one or more additives selected from the group consisting of fillers, stabilizers, antioxidants, flame retardants, lubricants, ultraviolet absorbers, colorants, adhesives, surfactants, antistatic agents and epoxy curing agents.

[12] An automotive underbody coating agent characterized by containing the plastisol composition according to any one of [1] to

[11] .

[13] An automotive sealant characterized by comprising the plastisol composition described in any of [1] to

[11] .

[0012] The plastisol composition of the present invention exhibits excellent storage stability and mechanical properties when processed at low temperatures (specifically, 70 to 90°C, particularly 80°C), and has excellent properties as a coating agent, especially for automotive underbody coatings and automotive sealants.

[0013] The present invention will now be described in detail. The plastisol composition of the present invention is a plastisol composition comprising at least a vinyl chloride-vinyl acetate copolymer (A), a compound (B) that satisfies (1) and (2) above, and a compound (C) that satisfies (3) above.

[0014] The vinyl chloride-vinyl acetate copolymer (A) constituting the plastisol composition of the present invention is a vinyl chloride-vinyl acetate copolymer having an average content of vinyl acetate polymerization units of 5 to 20% by weight. It is particularly suitable for automotive underbody coatings and automotive sealants, which are suitable for low-temperature processing, and is excellent in terms of strength characteristics. Therefore, it is preferable that the average content of vinyl acetate polymerization units be 7 to 18% by weight, particularly 7 to 16% by weight, and even more preferably 8 to 13% by weight. If the average content of vinyl acetate polymerization units is less than 5% by weight, low-temperature processing of the plastisol composition becomes difficult, or the molded product subjected to low-temperature processing has low mechanical strength. On the other hand, if the average content of vinyl acetate polymerization units exceeds 20% by weight, the viscosity of the sol changes significantly over time, resulting in poor long-term storage stability. The average content of vinyl acetate polymerization units can be measured, for example, with an infrared spectrophotometer at 1430 cm⁻¹. －１ Absorption values ​​at the absorption peak top due to in-plane angle bending in the vicinity of C-H and 1740 cm －１ It can be calculated from the absorption value of the absorption peak top due to the expansion and contraction of the C=O region in the vicinity.

[0015] The vinyl chloride-vinyl acetate copolymer is preferably a vinyl chloride-vinyl acetate copolymer for paste processing, as it is suitable for plastisol compositions and paste processing. The vinyl chloride-vinyl acetate copolymer for paste processing may be any vinyl chloride-vinyl acetate copolymer known to be suitable for paste processing, such as those obtained by polymerizing vinyl chloride monomer and vinyl acetate monomer by emulsion polymerization, microsuspension polymerization, seed emulsion polymerization, seed microsuspension polymerization, etc. Commercial products may also be used.

[0016] Further, the vinyl chloride-vinyl acetate copolymer is not only excellent in handleability when formed into a plastisol composition, but also excellent in absorbability for compounds acting as plasticizers, making it possible to provide a plastisol composition with excellent long-term storage stability and mechanical strength. For this reason, vinyl chloride-vinyl acetate copolymer particles composed of primary particles with a volume-based median diameter of 0.5 to 30 μm, particularly 0.8 to 10 μm, and further 1 to 5 μm are preferred. Such vinyl chloride-vinyl acetate copolymer particles can be produced by removing water from a vinyl chloride-vinyl acetate copolymer latex obtained by, for example, an emulsion polymerization method, a microsuspension polymerization method, a seed emulsion polymerization method, a seed microsuspension polymerization method, or the like. At that time, examples of the method for removing water from the vinyl chloride-vinyl acetate copolymer latex include methods by spray drying, fluidized bed drying, ventilation drying, rotary drying, conductive heating drying and the like. Among these, the method of obtaining granules / particles by spray drying is preferred since water can be removed efficiently. Further, when the granules / particles are too large, pulverization or the like may be performed. The volume-based median diameter of the primary particles can be determined, for example, from the central value of the volume-based particle size distribution measured with a disk centrifugal particle size distribution analyzer using the vinyl chloride-vinyl acetate copolymer latex before water removal, a dispersion liquid in which the vinyl chloride-vinyl acetate copolymer particles are dispersed into primary particles, or the like.

[0017] The compound (B) constituting the plastisol composition of the present invention has a (1) viscosity in viscoelasticity measurement under the measurement conditions of 23°C and a shear rate of 4 s －１ of 4000 to 500000 mPa·s, and (2) a Hansen solubility parameter of 16 to 22 (J / cm ３ ) １／２ The compound (B) is not particularly limited as long as it satisfies the above (1) and (2), and examples thereof include aromatic epoxy resins (B1), alicyclic epoxy resins (B2), polyester compounds (B3) and the like. Among these, a plastisol composition that is particularly excellent in long-term storage stability and heat moldability during solidification (gelation) is obtained, so that the viscosity is preferably 4000 to 300000 mPa·s, particularly 8000 to 50000 mPa·s, and the solubility parameter is 18 to 22 (J / cm ３) １／２ A compound that satisfies the following conditions is preferred. Here, if the viscosity at 23°C is less than 4000 mPa·s, it will have poor long-term storage stability and poor gelation moldability after storage. On the other hand, if it exceeds 500,000 mPa·s, the viscosity when forming a sol will be high, resulting in poor workability and difficulty in preparing the plastisol composition. Also, a solubility parameter of 16 (J / cm) is preferred. ３ ) １ / ２ If it is less than 22 (J / cm²), or if it is less than 22 (J / cm²), ３ ) １ / ２ If the viscosity exceeds this value, the molded product obtained by processing the plastisol composition at low temperatures will have inferior strength. The viscosity of compound (B) can be measured, for example, with a viscoelasticity measuring device, such as the MCR302 (product name) manufactured by Anton-Paar. Furthermore, the Hansen solubility parameter can be calculated, for example, using computer software (product name) HSPiP (Hansen Solubility Parameter in Practice).

[0018] The aromatic epoxy resin (B1) can be any resin belonging to the category of aromatic epoxy resins, having a glycidyl group in one molecule and having one or more aromatic skeletons such as a benzene ring core, a naphthalene ring core, or anthracene ring core in its skeleton. The glycidyl group and the aromatic skeleton may be directly bonded or bonded via ether bonds, ester bonds, amide bonds, urethane bonds, etc. Examples include epoxy resins that are bisphenol-type glycidyl ethers, epoxy resins that are phenol novolac-type glycidyl ethers, epoxy resins that are glycidylamines of aromatic amines, epoxy resins that are glycidyl esters of aromatic carboxylic acids, and mixtures of several of these may also be used. In particular, it is preferable that it acts as a plasticizer for the vinyl chloride-vinyl acetate copolymer (A).

[0019] Examples of bisphenol-type epoxy resins include bisphenol A diglycidyl ether (Hansen's solubility parameter (calculated value) 20.4 (J / cm²). ３ ) １／２), bisphenol F diglycidyl ether (Hansen's solubility parameter (calculated value) 21.4 (J / cm²) ３ ) １／２ Examples of epoxy resins include bisphenol S diglycidyl ether, bisphenol AD ​​diglycidyl ether, bromized bisphenol A diglycidyl ether, bisphenol glycidyl ether, etc.; phenol novolac type epoxy resins include, for example, phenol novolac epoxy resin, cresol novolac epoxy resin, etc.; aromatic amine type epoxy resins include, for example, tetraglycidyl diaminodiphenylmethane, tetraglycidyl dimetoxylendiamine, diglycidylaniline, diglycidyl toluidine, etc.; aromatic carboxylic acid type epoxy resins include, for example, diglycidyl phthalate ester, diglycidyl isophthalate ester, diglycidyl terephthalate ester, etc., and liquid bisphenol type epoxy resins, especially bisphenol A type epoxy resins, are preferred because they result in a plastisol composition with excellent long-term storage stability and heat moldability during solidification (gelling).

[0020] The alicyclic epoxy resin (B2) can be any resin belonging to the category of alicyclic epoxy resins, having a glycidyl group in one molecule and having one or more alicyclic skeletons such as a cyclopropane ring core, a cyclobutane ring core, or a cyclohexane ring core in its backbone. The glycidyl group and the alicyclic skeleton may be directly bonded or bonded via ether bonds, ester bonds, amide bonds, urethane bonds, etc. Examples include epoxy resins that are cyclohexane-type glycidyl ethers and epoxy resins that are glycidyl esters of alicyclic carboxylic acids, and mixtures of several of these may also be used. In particular, it is preferable that it acts as a plasticizer for the vinyl chloride-vinyl acetate copolymer (A).

[0021] Examples of glycidyl esters of alicyclic carboxylic acids include 1,2-cyclohexanedicarboxylic acid diglycidyl (Hansen solubility parameter (calculated value) 19.9 (J / cm²). ３ ) １／２Examples include 4,5-epoxycyclohexane-1,2-dicarboxylate di(2-ethylhexyl), 4,5-epoxycyclohexane-1,2-dicarboxylate di(9,10-epoxystearyl), etc.

[0022] The polyester compound (B3) can be any compound belonging to the category of polyester compounds, and can have multiple ester (carbonate-containing) bonds in one molecule, preferably 8 or more, and particularly preferably 10 or more. Examples include aliphatic polyesters of polycarboxylic acids and aliphatic polycarbonates of polyols, and mixtures of several of these are also acceptable. In particular, it is preferable that it acts as a plasticizer for the vinyl chloride-vinyl acetate copolymer (A).

[0023] Examples of aliphatic polyesters of polycarboxylic acids include adipic acid-based polyesters (Hansen solubility parameter (calculated value) 18.8 (J / cm²) ３ ) １／２ Examples include ), sebaciate-based polyesters, etc. As for aliphatic polycarbonates of polyhydric ols, for example, polycarbonate polyol (Hansen solubility parameter (calculated value) 19.1 (J / cm²) ３ ) １／２ Examples include:

[0024] Compound (C) constituting the plastisol composition of the present invention is a compound satisfying (3) a weight-average molecular weight of 300 to 2000. Any compound that satisfies (3) can be used as compound (C), for example, compounds having an aromatic ring and an aliphatic hydrocarbon group (C1), aliphatic ester compounds (C2), aliphatic oligomers (C3), all-aliphatic epoxy compounds (C4), silicon oligomers (C5), etc. Among these, compounds satisfying a weight-average molecular weight of 350 to 2000 are particularly preferred because they result in a plastisol composition with excellent long-term storage stability and heat moldability during solidification (gelation). If the weight-average molecular weight is less than 300, it will have poor long-term storage stability and poor gelation moldability after storage. On the other hand, if it exceeds 2000, the viscosity when forming a sol will be high, resulting in poor workability and difficulty in preparing the plastisol composition. The weight-average molecular weight can be measured using measuring devices such as gas chromatography, liquid chromatography, or gel permeation chromatography, depending on the acceptable range of weight-average molecular weight measurement.

[0025] The compound (C1) having an aromatic ring and an aliphatic hydrocarbon group can be any compound having an aromatic ring and an aliphatic hydrocarbon group, and the aromatic ring and the aliphatic hydrocarbon group may be directly bonded or bonded via a linkage such as an ester bond, amide bond, urethane bond, or ether bond. Examples of the aromatic ring include a benzene ring, a naphthalene ring, anthracene ring, etc. Examples of the aliphatic hydrocarbon group include an aliphatic hydrocarbon group having 1 to 20 carbon atoms, and particularly alkyl groups having 4 to 20 carbon atoms such as a butyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, a dodecyl group, an isononyl group, and an isodecyl group, and among these, it is preferable that it acts as a plasticizer for the vinyl chloride-vinyl acetate copolymer (A).

[0026] More specific examples of compounds (C1) having an aromatic ring and an aliphatic hydrocarbon group include, for example, phthalate esters such as bis(2-ethylhexyl) terephthalate, diisononyl phthalate, bis(2-ethylhexyl) phthalate, benzyl butyl phthalate, and diisodecyl phthalate; trimellitic acid esters such as trioctyl trimellitic acid, triisononyl 1,2,4-benzenetricarboxylic acid, tridecyl trimellitic acid, tributyl trimellitic acid, and trimethyl trimellitic acid; pyromellitic acid esters such as pyromellitic acid (2-ethylhexyl) ester; aromatic sulfonic acid esters such as alkylsulfonic acid phenyl esters; and alkylbenzenes such as octylbenzene, nonylbenzene, decylbenzene, and dodecylbenzene. Among these, phthalate esters, trimellitic acid esters, pyromellitic acid esters, and aromatic sulfonic acid esters are particularly preferred because they have excellent low-temperature processability and mechanical strength, making them excellent for automotive underbody coatings and automotive sealants.

[0027] The aliphatic ester compound (C2) can be any compound belonging to the category known as aliphatic ester compounds, and any compound having an ester bond with an aliphatic hydrocarbon group. Examples of aliphatic hydrocarbon groups include aliphatic hydrocarbon groups having 1 to 20 carbon atoms, and in particular alkyl groups having 4 to 20 carbon atoms such as butyl, hexyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, and isononyl groups. Other examples include aliphatic polyester oligomers and aliphatic polycarbonate oligomers with a weight-average molecular weight of 300 to 2000.

[0028] More specific examples of aliphatic ester compounds (C2) include, for example, adipic acid esters such as bis(2-ethylhexyl) adipate, diisononyl adipate, and diisodecyl adipate; citrate esters such as tributyl acetylcitrate; sebacate acid esters such as bis(2-ethylhexyl) sebacate; and alicyclic carboxylic acid esters such as diisononyl cyclohexane-1,2-dicarboxylic acid. Furthermore, adipic acid-based polyester oligomers and sebacate acid-based polyester oligomers can also be mentioned. Note that an aliphatic polyester oligomer with a weight-average molecular weight of 2000 (for example, an adipic acid-based polyester oligomer) was subjected to a shear rate of 4s at 23°C. －１ When viscoelasticity measurements were performed under these measurement conditions, the viscosity was approximately 3000 mPa·s, and the aliphatic ester compound (C2) satisfying a weight-average molecular weight of 300 to 2000 is distinguished from the polyester compound (B3) satisfying a viscosity of 4000 to 500000 mPa·s.

[0029] Aliphatic oligomers (C3) can be any compound or macromolecule oligomer belonging to the category of aliphatic compounds, and examples include alkyls, which are saturated hydrocarbon compounds; alkylenes, acetylenes, and their macromers, which are unsaturated hydrocarbon compounds; polyalkylenes; polyoxyalkylenes; polyacrylics, etc.

[0030] More specific examples of aliphatic oligomers (C3) include, for example, polyalkylenes such as polyethylene, polypropylene, polybutene, and polyhexene; polyoxyalkylenes such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; liquid paraffin; and acrylics such as polyethyl (meth)acrylate, polymethyl (meth)acrylate, polybutyl (meth)acrylate, poly-2-ethylhexyl (meth)acrylate, polyhydroxyethyl (meth)acrylate, polyglycidyl (meth)acrylate, and poly(meth)acrylic acid. Examples include acrylic polyols, which are homopolymers or copolymers of hydroxyl-containing (meth)acrylic monomers such as hydroxyalkyl (meth)acrylic acid esters like 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; glycerin (meth)acrylic acid monoesters; triol (meth)acrylic acid monoesters such as trimethylolpropane (meth)acrylic acid monoesters; and others.

[0031] The total aliphatic epoxy compound (C4) can be any aliphatic compound having an epoxy group, such as epoxidized soybean oil or epoxidized linseed oil.

[0032] More specific examples of silicon-based oligomers (C5) include, for example, dimethylpolysiloxane oligomers, methylpolysiloxane oligomers, methylphenylpolysiloxane oligomers, methylhydrogenpolysiloxane oligomers, octamethylcyclotetrasiloxane oligomers, octamethylcyclopentasiloxane oligomers, decamethylcyclohexasiloxane oligomers, stearoxysilicon, and the like.

[0033] The plastisol composition of the present invention contains at least a vinyl chloride-vinyl acetate copolymer (A), compound (B), and compound (C), particularly a combination of the vinyl chloride-vinyl acetate copolymer (A), an aromatic epoxy resin (B1), and a compound (C1) having an aromatic ring and an aliphatic hydrocarbon group, resulting in excellent storage stability and excellent processability and mechanical strength even when processed under low temperature conditions such as 70 to 90°C, preferably 75 to 85°C, and especially 80°C. It is particularly excellent as a coating agent, and even more so for automotive underbody coatings and automotive sealants. The blending ratio is 80 to 250 parts by weight of compound (B) and compound (C) per 100 parts by weight of vinyl chloride-vinyl acetate copolymer (A). It is preferable that the blending ratio is 90 to 200 parts by weight, particularly 100 to 180 parts by weight, and more preferably 110 to 170 parts by weight, as this provides an excellent balance between long-term storage stability and low-temperature processability, making it suitable for low-temperature processing as a plastisol composition for automotive underbody coatings and automotive sealants. Here, if the total amount of compound (B) and compound (C) is less than 80 parts by weight, plasticization will be insufficient, making it difficult to prepare a plastisol composition. On the other hand, if the total amount exceeds 250 parts by weight, the molded product obtained by processing the plastisol composition at low temperatures will have inferior strength.

[0034] Furthermore, the blending ratio of compound (B) and compound (C) in the plastisol composition of the present invention is such that the ratio of compound (C) to the total amount of compound (B) and compound (C) is 10 to 60% by weight, in order to achieve excellent storage stability and excellent processability and mechanical strength even when processed under low temperature conditions of 80°C. In particular, a plastisol composition for automotive underbody coatings and a plastisol composition for automotive sealants that has an excellent balance between long-term storage stability and low-temperature processability and is suitable for low-temperature processing at 70 to 90°C, preferably 75 to 85°C, and especially 80°C is preferable, so the ratio of compound (C) to the total amount of compound (B) and compound (C) is 11 to 55% by weight, and more preferably 12 to 52% by weight. Here, if the blending ratio of compound (C) is less than 10% by weight, the mechanical elongation when subjected to low-temperature processing will be poor. On the other hand, if it exceeds 60% by weight, the long-term storage stability will be poor.

[0035] The plastisol composition of the present invention may contain additives commonly added to plastisol compositions made of vinyl chloride resin for paste processing, such as fillers, stabilizers, antioxidants, flame retardants, lubricants, ultraviolet absorbers, colorants such as pigments, surfactants, adhesives, antistatic agents, and epoxy curing agents, without departing from the objectives of the present invention, and the amounts of these additives may also be within the range of general use.

[0036] The plastisol composition of the present invention can be prepared by uniformly mixing and dispersing a vinyl chloride-vinyl acetate copolymer (A), compound (B), compound (C), and other additives as needed, using conventionally known mixing and dispersing machines and kneaders, such as a kneader, disper, planetary mixer, attritor, ball mill, grain mill, blender, twin-screw mixer, vertical high-speed stirrer, roll mill, dissolver, etc.

[0037] Furthermore, the plastisol composition of the present invention exhibits excellent mechanical properties, especially in low-temperature processing, and is particularly excellent for automotive underbody coatings and sealants. Therefore, it is preferable that the tensile strength conforming to JIS K6251 is 0.5 MPa or higher, and the tensile elongation is 50% or higher, particularly 60% or higher. As a method for measuring the tensile strength in this case, for example, the plastisol composition is heated at 80°C for 30 minutes to form a 2 mm thick sheet, a JIS No. 3 dumbbell test piece is prepared from the sheet, and the tensile strength is measured at 23°C and 50 mm / min in accordance with JIS K6251.

[0038] The plastisol composition of the present invention exhibits excellent storage stability, and even under low processing conditions of 70 to 90°C, preferably 75 to 85°C, and especially 80°C, it has excellent processability and mechanical properties, making it suitable for various applications such as films, sheets, wallpaper, flooring materials, and foamed sheets, particularly as a coating agent, and even as an automotive underbody coating agent and automotive sealant.

[0039] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0040] The following describes the evaluation and measurement methods for vinyl chloride-vinyl acetate copolymers and plastisol compositions.

[0041] <Average Content of Vinyl Acetate Polymerization Units> The average content (by weight) of vinyl acetate polymerization units contained in the vinyl chloride-vinyl acetate copolymer (sometimes referred to as VAc content) was calculated using the following formula with a measurement sample prepared by mixing 100 mg of vinyl chloride-vinyl acetate copolymer and 10 mg of potassium bromide, grinding and molding it, and using an infrared spectrophotometer (Shimadzu Corporation, product name FTIR-8100A).

[0042] VAc content = (3.73 x B / A + 0.024) x 1.04 A: 1430 cm －１ Abs. value of the absorption peak top due to in-plane bending of C-H plane in the vicinity.

[0043] B: 1740cm －１ Abs. value of the absorption peak top due to C=O stretching in the vicinity.

[0044] <Primary particle size of vinyl chloride-vinyl acetate copolymer> The obtained vinyl chloride-vinyl acetate copolymer latex was measured using a disk centrifugal particle size distribution analyzer (manufactured by Nippon Luft Co., Ltd., product name DC24000UHR) to measure the volume-based primary particle size distribution, and the volume-based median diameter, which is the central value, was defined as the particle size.

[0045] <Solubility parameter of compound (B) Hansen> The solubility parameter (SP value) of Hansen is expressed as δ by the following formula (unit: (J / cm) ３ ) １／２ )

[0046] δ = (δd ２ +δp ２ +δh ２ ) １／２ Here, δd represents the dispersion term, δp represents the polarity term, and δh represents the hydrogen bonding term (all units are (J / cm)). ３ ) １／２ ).

[0047] The δ, δd, δp, and δh values ​​for each plasticizer were calculated using commercially available computer software (product name) HSPiP (Hansen Solubility Parameter in Practice).

[0048] <Viscosity of Compound (B)> Viscoelasticity was measured at 23°C and 80°C using a viscoelasticity measuring device (Anton-Paar, product name MCR302) with a parallel plate PP25 / P2 at a shear rate of 4s. －１ It was measured using [this method].

[0049] <Thickening Rate of Plastisol Composition> After storing the obtained plastisol composition at 23°C for 24 hours, the viscoelasticity was measured using a parallel plate PP25 / P2 with a shear rate of 4s using an Anton-Paar (product name) MCR302 viscoelasticity measuring device. －１ The viscosity measured was defined as the initial viscosity (α). Furthermore, after storage at 40°C for 7 days, the viscosity (β) was measured using the same method as the initial viscosity, and the viscosity increase rate (%) was calculated from this value and the initial viscosity (α) using the following formula. As one guideline for evaluating long-term storage stability, a viscosity increase rate of 1000% or less was judged to have excellent long-term storage stability.

[0050] Thickening rate (%) = ((β - α) / α) × 100 <Tensile strength and tensile elongation> A plastisol composition that had been kneaded and defoamed was applied to release paper and heated at 80°C for 30 minutes to produce a 2 mm thick paste PVC sheet. A test specimen was made from the obtained paste PVC sheet using a JIS No. 3 dumbbell, and markings were made in the center of the test specimen at 20 mm intervals. The specimen was pulled at a speed of 50 mm / min at 23°C in accordance with JIS K6251, and the load at the time of breakage was measured to determine the breaking strength and elongation. As one guideline for evaluating strength, a tensile strength of 0.5 MPa or higher was judged to be excellent in strength. Also, as one guideline for evaluating flexibility, a tensile elongation of 50% or higher was judged to be excellent in flexibility.

[0051] Synthesis Example 1 (Synthesis example of seeds containing initiators, etc.) 1 m ３360 kg of deionized water, 300 kg of vinyl chloride monomer, 10.5 kg of lauroyl peroxide, and 30 kg of 15% by weight sodium dodecylbenzenesulfonate aqueous solution were charged into an autoclave. The polymerization solution was circulated using a homogenizer for 2 hours to homogenize it, and then the temperature was raised to 45°C to proceed with polymerization. After the pressure dropped by 0.2 MPa from the saturated vapor pressure of vinyl chloride monomer at 45°C, the unreacted vinyl chloride monomer was recovered. The resulting initiator-containing seed latex (hereinafter abbreviated as Seed 1) had a particle size of 0.60 μm and a solid content concentration of 32%.

[0052] Preparation Example 1: 500 g of deionized water, 484 g of vinyl chloride monomer and 108 g of vinyl acetate monomer as the first stage monomers, 8.6 g of 5% sodium lauryl sulfate aqueous solution, 84 g of Seed 1, 4 g of 0.1% copper sulfate aqueous solution, and 10.6 g of a 2 wt% sodium phosphate / 1 wt% potassium hydroxide mixture as a buffer were charged into a 2.5 liter autoclave. The temperature of this reaction mixture was then raised to 35°C to start the first stage polymerization, and a 0.06 wt% ascorbic acid aqueous solution was continuously added throughout the entire polymerization time to maintain the polymerization temperature. A total of 218 g of 0.06 wt% ascorbic acid aqueous solution was added throughout the entire polymerization time. When the polymerization conversion rate reached 50%, 138 g of vinyl chloride monomer was charged into the 2.5 liter autoclave as the second stage monomer, and the second stage polymerization was continued at a polymerization temperature of 35°C. Furthermore, when the polymerization conversion rate reached 80% of the sum of the first and second stage monomers, 69 g of vinyl chloride monomer was added to a 2.5-liter autoclave as the third stage monomer, and the third stage polymerization was continued at a polymerization temperature of 35°C until the polymerization was terminated when the polymerization conversion rate reached 89% of the sum of the mixed monomers. During the entire polymerization process, 120 g of a 5% sodium lauryl sulfate aqueous solution was continuously added. The total polymerization time from start to finish was 792 minutes.

[0053] Then, the unreacted monomers were recovered to form a latex, which was spray-dried in a spray dryer at a hot air inlet temperature of 158°C and an outlet temperature of 55°C to obtain vinyl chloride-vinyl acetate copolymer particles for paste processing.

[0054] The obtained vinyl chloride-vinyl acetate copolymer had an average vinyl acetate polymerization unit content of 9.0% by weight and a primary particle volume-based median diameter of 1.4 μm.

[0055] Preparation Example 2: 500 g of deionized water, 473 g of vinyl chloride monomer and 124 g of vinyl acetate monomer as the first stage monomers, 8.6 g of 5% sodium lauryl sulfate aqueous solution, 84 g of Seed 1, 4 g of 0.1% copper sulfate aqueous solution, and 10.6 g of a 2 wt% sodium phosphate / 1 wt% potassium hydroxide mixed aqueous solution as a buffer were charged into a 2.5 liter autoclave. The temperature of this reaction mixture was then raised to 35°C to start the first stage polymerization, and a 0.06 wt% ascorbic acid aqueous solution was continuously added throughout the entire polymerization time to maintain the polymerization temperature. A total of 128 g of 0.06 wt% ascorbic acid aqueous solution was added throughout the entire polymerization time. When the polymerization conversion rate reached 50%, 135 g of vinyl chloride monomer was charged into the 2.5 liter autoclave as the second stage monomer, and the second stage polymerization was continued at a polymerization temperature of 35°C. Furthermore, when the polymerization conversion rate reached 80% of the sum of the first and second stage monomers, 68 g of vinyl chloride monomer was added to a 2.5-liter autoclave as the third stage monomer, and the third stage polymerization was continued at a polymerization temperature of 35°C until the polymerization was terminated when the polymerization conversion rate reached 89% of the sum of the mixed monomers. During the entire polymerization process, 120 g of a 5% sodium lauryl sulfate aqueous solution was continuously added. The total polymerization time from start to finish was 782 minutes.

[0056] Then, the unreacted monomers were recovered to form a latex, which was spray-dried in a spray dryer at a hot air inlet temperature of 158°C and an outlet temperature of 55°C to obtain vinyl chloride-vinyl acetate copolymer particles for paste processing.

[0057] The obtained vinyl chloride-vinyl acetate copolymer had an average vinyl acetate polymerization unit content of 11.7% by weight and a primary particle volume-based median diameter of 1.4 μm.

[0058] Preparation Example 3 In a 2.5-liter autoclave equipped with a stirrer, 210 g of deionized water, 25 g of lauroyl peroxide, 792 g of 2% by weight of water-soluble polyvinyl alcohol (product name Kuraray Poval 7-92, manufactured by Kuraray Co., Ltd.), and 56 g of a 2% by weight sodium phosphate / 1% by weight potassium hydroxide mixture as a buffer were charged, and vacuum degassing was performed. After degassing, 576 g of vinyl chloride monomer and 143 g of vinyl acetate monomer were charged, and homogenization treatment was performed using a homogenizer for 40 minutes. After homogenization treatment, the temperature inside the can was heated to 35°C, and polymerization was started. Polymerization was stopped when the pressure inside the can reached 0.18 MPa. After polymerization was completed, the unreacted monomers in the can were recovered to form latex, which was filtered, and then spray-dried using a spray dryer at a hot air inlet temperature of 158°C and an outlet temperature of 55°C to obtain vinyl chloride-vinyl acetate copolymer as vinyl chloride-vinyl acetate copolymer particles for paste processing.

[0059] The obtained vinyl chloride-vinyl acetate copolymer had an average vinyl acetate polymerization unit content of 10.9% by weight and a primary particle volume-based median diameter of 14.1 μm.

[0060] Preparation Example 4: 500 g of deionized water, 484 g of vinyl chloride monomer and 108 g of vinyl acetate monomer as the first stage monomers, 8.6 g of 5% sodium lauryl sulfate aqueous solution, 84 g of Seed 1, 4 g of 0.1% copper sulfate aqueous solution, and 10.6 g of a 2 wt% sodium phosphate / 1 wt% potassium hydroxide mixture as a buffer were charged into a 2.5 liter autoclave. The temperature of this reaction mixture was then raised to 35°C to start the first stage polymerization, and a 0.06 wt% ascorbic acid aqueous solution was continuously added throughout the entire polymerization time to maintain the polymerization temperature. A total of 218 g of 0.06 wt% ascorbic acid aqueous solution was added throughout the entire polymerization time. When the polymerization conversion rate reached 50%, 138 g of vinyl chloride monomer was charged into the 2.5 liter autoclave as the second stage monomer, and the second stage polymerization was continued at a polymerization temperature of 35°C. Furthermore, when the polymerization conversion rate reached 80% of the sum of the first and second stage monomers, 69 g of vinyl chloride monomer was added to a 2.5-liter autoclave as the third stage monomer, and the third stage polymerization was continued at a polymerization temperature of 35°C until the polymerization was terminated when the polymerization conversion rate reached 89% of the sum of the mixed monomers. During the entire polymerization process, 120 g of a 5% sodium lauryl sulfate aqueous solution was continuously added. The total polymerization time from start to finish was 792 minutes.

[0061] Then, the unreacted monomers were recovered to form latex, and 400 g of a 2% by weight aqueous solution of water-soluble polyvinyl alcohol (product name Kuraray Poval 7-92, manufactured by Kuraray Co., Ltd.) was added. Spray drying was performed using a spray dryer with a hot air inlet temperature of 158°C and an outlet temperature of 55°C to obtain vinyl chloride-vinyl acetate copolymer as vinyl chloride-vinyl acetate copolymer particles for paste processing.

[0062] The obtained vinyl chloride-vinyl acetate copolymer had an average vinyl acetate polymerization unit content of 9.0% by weight and a primary particle volume-based median diameter of 1.4 μm.

[0063] Example 1: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, add bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm²). ３ ) １／２ 105 parts by weight of ) and 15 parts by weight of diisononyl phthalate ((trade name) DINP, manufactured by J-Plus Co., Ltd.; molecular weight 419) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition. The physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 1.

[0064] Example 2 A plastisol composition was obtained in the same manner as in Example 1, except that the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 2 was used. A paste vinyl sheet was then prepared and its physical properties were evaluated. The results are shown in Table 1.

[0065] Example 3: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was added. ３ ) １／２ ) 107 parts by weight, diisononyl phthalate ((trade name) DINP, manufactured by J-Plus Co., Ltd.; molecular weight 419) 53 parts by weight, fatty acid treated calcium carbonate ((trade name) SP-60, manufactured by Takehara Chemical Industry Co., Ltd.) 40 parts by weight as a thixotropic agent, and amine-based curing agent ((trade name) ADEKA Hardener EH-4357S, manufactured by ADEKA Corporation) 4 parts by weight as an epoxy curing agent were mixed and kneaded and defoamed at 23°C for 3 minutes using a dissolver to obtain a plastisol composition.

[0066] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 1.

[0067] Example 4: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was used as a plasticizer. ３ ) １／２ 60 parts by weight of ) and 60 parts by weight of diisononyl phthalate ((trade name) DINP, manufactured by J-Plus Co., Ltd.; molecular weight 419) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition.

[0068] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 1.

[0069] Example 5: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was used as a plasticizer. ３ ) １／２ 70 parts by weight of ), 50 parts by weight of diisononyl phthalate ((trade name) DINP, manufactured by J-Plus Co., Ltd.; molecular weight 419), 30 parts by weight of fatty acid-treated calcium carbonate ((trade name) SP-60, manufactured by Takehara Chemical Industry Co., Ltd.) as a thixotropic agent, and 20 parts by weight of heavy calcium carbonate ((trade name) NN500, manufactured by Sankyo Seifun Co., Ltd.) as a filler were mixed and kneaded and defoamed at 23°C for 3 minutes using a dissolver to obtain a plastisol composition.

[0070] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 1.

[0071]

[0072] Example 6 A plastisol composition was obtained using the same method as in Example 1, except that bis(2-ethylhexyl) phthalate (trade name DOP, manufactured by J-Plus Co., Ltd.; molecular weight 390) was used instead of diisononyl phthalate. A paste PVC sheet was then prepared and its physical properties were evaluated. The results are shown in Table 2.

[0073] In Example 7, a plastisol composition was obtained using the same method as in Example 1, except that bis(2-ethylhexyl) terephthalate ((trade name) DOTP, manufactured by J-Plus Co., Ltd.; molecular weight 391) was used instead of diisononyl phthalate. A paste PVC sheet was then prepared, and its physical properties were evaluated. The results are shown in Table 2.

[0074] Example 8 A plastisol composition was obtained using the same method as in Example 1, except that trioctyl trimellitate (trade name TOTM, manufactured by J-Plus Co., Ltd.; molecular weight 546) was used instead of diisononyl phthalate. A paste PVC sheet was then prepared and its physical properties were evaluated. The results are shown in Table 2.

[0075] Example 9: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was added. ３ ) １／２ 70 parts by weight of ), 50 parts by weight of trioctyl trimellitate ((trade name) TOTM, manufactured by J-Plus Co., Ltd.; molecular weight 546), and 30 parts by weight of fatty acid-treated calcium carbonate ((trade name) SP-60, manufactured by Takehara Chemical Industry Co., Ltd.) as a thixotropic agent were mixed and kneaded and defoamed at 23°C for 3 minutes using a dissolver to obtain a plastisol composition.

[0076] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 2.

[0077] Example 10: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was added. ３ ) １／２70 parts by weight of ), 50 parts by weight of pyromellitic acid (2-ethylhexyl) ester ((product name) Adekasizer UL-80, manufactured by ADEKA Corporation; molecular weight 479), and 30 parts by weight of fatty acid-treated calcium carbonate ((product name) SP-60, manufactured by Takehara Chemical Industry Co., Ltd.) as a thixotropic agent were mixed and kneaded and defoamed at 23°C for 3 minutes using a dissolver to obtain a plastisol composition.

[0078] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 2.

[0079] In Example 11, a plastisol composition was obtained using the same method as in Example 1, except that phenyl alkylsulfonate ((trade name) MESAMOLL, manufactured by LANXESS; molecular weight 382) was used instead of diisononyl phthalate. A paste PVC sheet was then prepared and its physical properties were evaluated. The results are shown in Table 2.

[0080] Example 12 A plastisol composition was obtained using the same method as in Example 1, except that the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 3 was used. A paste vinyl sheet was then prepared and its physical properties were evaluated. The results are shown in Table 2.

[0081] Example 13: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 4, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was added as a plasticizer. ３ ) １／２ 70 parts by weight of ), 50 parts by weight of diisononyl phthalate ((trade name) DINP, manufactured by J-Plus Co., Ltd.; molecular weight 419), 30 parts by weight of fatty acid-treated calcium carbonate ((trade name) SP-60, manufactured by Takehara Chemical Industry Co., Ltd.) as a thixotropic agent, and 30 parts by weight of heavy calcium carbonate ((trade name) NN500, manufactured by Sankyo Seifun Co., Ltd.) as a filler were mixed and kneaded and defoamed at 23°C for 3 minutes using a dissolver to obtain a plastisol composition.

[0082] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 2.

[0083]

[0084] Synthesis Example 2 (Synthesis example of seed containing initiator, etc.) 1 m ３ 360 kg of deionized water, 300 kg of vinyl chloride monomer, 5.3 kg of lauroyl peroxide, and 30 kg of 15 wt% sodium dodecylbenzenesulfonate aqueous solution were charged into a stainless steel autoclave. The mixture was homogenized by circulating it in a homogenizer for 3 hours, and then the temperature of the reaction system was raised to 45°C to start polymerization. After the pressure in the polymerization system decreased, the unreacted vinyl chloride monomer was recovered. The resulting initiator-containing seed latex (hereinafter abbreviated as Seed 2) had a particle size of 0.55 μm and a solid content concentration of 35 wt%.

[0085] Preparation Example 5: 500 g of deionized water, 449 g of vinyl chloride monomer and 159 g of vinyl acetate monomer as the first stage monomers, 8.6 g of 5% sodium lauryl sulfate aqueous solution, 81 g of Seed 1, 4 g of 0.1% copper sulfate aqueous solution, and 10.6 g of 2 wt% sodium phosphate / 1 wt% potassium hydroxide mixed aqueous solution as a buffer were charged into a 2.5 liter autoclave. The temperature of this reaction mixture was then raised to 35°C to start the first stage polymerization, and a 0.06 wt% ascorbic acid aqueous solution was continuously added throughout the entire polymerization time to maintain the polymerization temperature. A total of 210 g of 0.06 wt% ascorbic acid aqueous solution was added throughout the entire polymerization time. When the polymerization conversion rate reached 50%, 128 g of vinyl chloride monomer was charged into the 2.5 liter autoclave as the second stage monomer, and the second stage polymerization was continued at a polymerization temperature of 35°C. Furthermore, when the polymerization conversion rate reached 80% of the sum of the first and second stage monomers, 64 g of vinyl chloride monomer was added to a 2.5-liter autoclave as the third stage monomer, and the third stage polymerization was continued at a polymerization temperature of 35°C until the polymerization was terminated when the polymerization conversion rate reached 89% of the sum of the mixed monomers. During the entire polymerization process, 120 g of a 5% sodium lauryl sulfate aqueous solution was continuously added. The total polymerization time from start to finish was 758 minutes.

[0086] Then, the unreacted monomers were recovered to form a latex, which was spray-dried in a spray dryer at a hot air inlet temperature of 158°C and an outlet temperature of 55°C to obtain vinyl chloride-vinyl acetate copolymer particles for paste processing.

[0087] The obtained vinyl chloride-vinyl acetate copolymer had an average vinyl acetate polymerization unit content of 13.9% by weight and a primary particle volume-based median diameter of 1.4 μm.

[0088] Preparation Example 6: 720 g of deionized water, 800 g of vinyl chloride monomer, 8.8 g of 5% sodium lauryl sulfate aqueous solution, 98 g of Seed 2, 8 g of 0.1% copper sulfate aqueous solution, and 18.5 g of 0.9 wt% boric acid / 0.1 wt% potassium hydroxide mixed aqueous solution as a buffer were charged into a 2.5 liter autoclave. The temperature of this reaction mixture was then raised to 48°C to start polymerization, and 0.05 wt% ascorbic acid aqueous solution was continuously added throughout the entire polymerization time to maintain the polymerization temperature. A total of 139 g of 0.05 wt% ascorbic acid aqueous solution was added throughout the entire polymerization time. Polymerization was terminated when the polymerization conversion rate reached 86% of the monomer. During the period from the start to the end of polymerization, 60 g of 5% sodium lauryl sulfate aqueous solution was continuously added. The total polymerization time from the start to the end of polymerization was 583 minutes.

[0089] Then, the unreacted monomer was recovered to form latex, which was spray-dried in a spray dryer at a hot air inlet temperature of 158°C and an outlet temperature of 55°C to obtain vinyl chloride polymer as vinyl chloride polymer particles for paste processing.

[0090] The obtained vinyl chloride polymer had a primary particle volume-based median diameter of 1.3 μm.

[0091] Preparation Example 7: 500 g of deionized water, 379 g of vinyl chloride monomer and 259 g of vinyl acetate monomer as the first stage monomers, 8.6 g of 5% sodium lauryl sulfate aqueous solution, 83 g of Seed 1, 4 g of 0.1% copper sulfate aqueous solution, and 10.6 g of a 2 wt% sodium phosphate / 1 wt% potassium hydroxide mixture as a buffer were charged into a 2.5 liter autoclave. The temperature of this reaction mixture was then raised to 35°C to start the first stage polymerization, and a 0.06 wt% ascorbic acid aqueous solution was continuously added throughout the entire polymerization time to maintain the polymerization temperature. A total of 268 g of 0.06 wt% ascorbic acid aqueous solution was added throughout the entire polymerization time. When the polymerization conversion rate reached 50%, 108 g of vinyl chloride monomer was charged into the 2.5 liter autoclave as the second stage monomer, and the second stage polymerization was continued at a polymerization temperature of 35°C. Furthermore, when the polymerization conversion rate reached 80% of the sum of the first and second stage monomers, 54 g of vinyl chloride monomer was added to a 2.5-liter autoclave as the third stage monomer, and the third stage polymerization was continued at a polymerization temperature of 35°C until the polymerization was terminated when the polymerization conversion rate reached 89% of the sum of the mixed monomers. During the entire polymerization process, 120 g of a 5% sodium lauryl sulfate aqueous solution was continuously added. The total polymerization time from start to finish was 1276 minutes.

[0092] Then, the unreacted monomers were recovered to form a latex, which was spray-dried in a spray dryer at a hot air inlet temperature of 158°C and an outlet temperature of 55°C to obtain vinyl chloride-vinyl acetate copolymer particles for paste processing.

[0093] The obtained vinyl chloride-vinyl acetate copolymer had an average vinyl acetate polymerization unit content of 22.7% by weight, and the volume-based median diameter of the primary particles was 1.4 μm.

[0094] Comparative Example 1 To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 5, 100 parts by weight of diisononyl phthalate ((trade name) DINP, manufactured by J-Plus Co., Ltd.; molecular weight 419), 70 parts by weight of fatty acid-treated calcium carbonate ((trade name) SP-60, manufactured by Takehara Chemical Industry Co., Ltd.) as a thixotropic agent, 70 parts by weight of heavy calcium carbonate ((trade name) NN500, manufactured by Sankyo Seifun Co., Ltd.) as a filler, and 20 parts by weight of naphthenic hydrocarbon solvent ((trade name) Exxsol D80, manufactured by Tonen General Sekiyu K.K.) as a diluent were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition, and a paste PVC sheet was prepared and its physical properties were evaluated. The results are shown in Table 3. The obtained plastisol composition had a thickening rate of 4851% after storage at 40°C for 7 days, indicating poor long-term storage stability.

[0095] Comparative Example 2: A plastisol composition was obtained in the same manner as in Example 1, except that the vinyl chloride polymer obtained in Preparation Example 6 was used. An attempt was made to prepare a sheet by heating at 80°C for 30 minutes, but it did not harden (gel) and a sheet could not be prepared. The evaluation results are shown in Table 3.

[0096] Comparative Example 3: Except for using the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 7, the same method as in Example 1 was used, and kneading was attempted at 23°C using a dissolver. However, the resulting plastisol composition solidified (gelled) during the initial viscosity measurement, making it impossible to perform other evaluations.

[0097] Comparative Example 4: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was added. ３ ) １／２ When 51 parts by weight of ) and 9 parts by weight of diisononyl phthalate ((trade name) DINP, manufactured by J-Plus Co., Ltd.; molecular weight 419) were mixed and kneaded at 23°C using a dissolver, efficient kneading was difficult due to the absorption of the plasticizer, and a plastisol composition could not be prepared.

[0098] Comparative Example 5: 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, mixed with bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm²). ３ ) １／２ 215 parts by weight of ), 105 parts by weight of diisononyl phthalate ((trade name) DINP, manufactured by J-Plus Co., Ltd.; molecular weight 419), 80 parts by weight of fatty acid-treated calcium carbonate ((trade name) SP-60, manufactured by Takehara Chemical Industry Co., Ltd.) as a thixotropic agent, and 32 parts by weight of an amine-based curing agent ((trade name) ADEKA Hardener EH-4357S, manufactured by ADEKA Corporation) as an epoxy curing agent were mixed and kneaded and degassed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition, and a paste PVC sheet was prepared and its physical properties were evaluated. The results are shown in Table 3. The obtained sheet had a low tensile strength of 0.1 MPa.

[0099] Comparative Example 6: 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, mixed with bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm²). ３ ) １／２ 110 parts by weight of ) and 10 parts by weight of diisononyl phthalate ((trade name) DINP, manufactured by J-Plus Co., Ltd.; molecular weight 419) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition, and a paste PVC sheet was prepared and its physical properties were evaluated. The results are shown in Table 3. The obtained sheet had a low tensile elongation of 40%.

[0100] Comparative Example 7: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was added. ３ ) １／２40 parts by weight of ) and 80 parts by weight of diisononyl phthalate ((trade name) DINP, manufactured by J-Plus Co., Ltd.; molecular weight 419) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition, and a paste PVC sheet was prepared and its physical properties were evaluated. The results are shown in Table 3. The obtained plastisol composition had a thickness increase of 1018% after storage at 40°C for 7 days, indicating poor long-term storage stability.

[0101]

[0102] Example 14 A plastisol composition was obtained using the same method as in Example 1, except that tributyl acetylcitrate (trade name ATBC, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.; molecular weight 402) was used instead of diisononyl phthalate. A paste PVC sheet was then prepared and its physical properties were evaluated. The results are shown in Table 4.

[0103] Example 15: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was used as a plasticizer. ３ ) １／２ 90 parts by weight of ) and 30 parts by weight of tributyl acetylcitrate ((trade name) ATBC, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.; molecular weight 402) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition.

[0104] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 4.

[0105] Example 16: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was used as a plasticizer. ３ ) １／２90 parts by weight of ) and 30 parts by weight of acrylic oligomer ((product name) UP-1021, manufactured by Toagosei Co., Ltd.; molecular weight 1600) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition.

[0106] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 4.

[0107] Example 17: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, an adipic acid-based polyester (product name PN-5090, manufactured by ADEKA Corporation; viscosity 12400 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was added as a plasticizer. ３ ) １／２ 70 parts by weight of ) and 18 parts by weight of trioctyl trimellitate ((trade name) TOTM, manufactured by J-Plus Co., Ltd.; molecular weight 546) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition.

[0108] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 4.

[0109] Example 18: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was added as a plasticizer. ３ ) １／２ 70 parts by weight of ), 50 parts by weight of bis(2-ethylhexyl) terephthalate ((trade name) DOTP, manufactured by J-Plus Co., Ltd.; molecular weight 391), 25 parts by weight of fatty acid-treated calcium carbonate ((trade name) SP-60, manufactured by Takehara Chemical Industry Co., Ltd.) as a thixotropic agent, and 30 parts by weight of heavy calcium carbonate ((trade name) NN500, manufactured by Sankyo Seifun Co., Ltd.) as a filler were mixed and kneaded and defoamed at 23°C for 3 minutes using a dissolver to obtain a plastisol composition.

[0110] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 4.

[0111] Example 19 To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was added as a plasticizer. ３ ) １／２ 70 parts by weight of ), 50 parts by weight of diisodecyl phthalate ((trade name) DIDP, manufactured by J-Plus Co., Ltd.; molecular weight 447), 25 parts by weight of fatty acid-treated calcium carbonate ((trade name) LV-80, manufactured by Takehara Chemical Industry Co., Ltd.) as a thixotropic agent, and 40 parts by weight of heavy calcium carbonate ((trade name) BF300, manufactured by Shiraishi Calcium Co., Ltd.) as a filler were mixed and kneaded and defoamed at 23°C for 3 minutes using a dissolver to obtain a plastisol composition.

[0112] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 4.

[0113] Example 20: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was used as a plasticizer. ３ ) １／２ 70 parts by weight of ), 50 parts by weight of cyclohexane-1,2-dicarboxylic acid diisononyl ((trade name) DINCH, manufactured by BASF Japan Ltd.; molecular weight 423), 25 parts by weight of fatty acid-treated calcium carbonate ((trade name) SP-60, manufactured by Takehara Chemical Industry Co., Ltd.) as a thixotropic agent, and 30 parts by weight of heavy calcium carbonate ((trade name) NN500, manufactured by Sankyo Seifun Co., Ltd.) as a filler were mixed and kneaded and defoamed at 23°C for 3 minutes using a dissolver to obtain a plastisol composition.

[0114] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 4.

[0115]

[0116] Comparative Example 8: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, alkyl sulfonic acid phenyl ester ((trade name) MESAMOLL, manufactured by LANXESS; viscosity 125 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm)) was used as a plasticizer. ３ ) １／２ 90 parts by weight of ) and 30 parts by weight of trioctyl trimellitate ((trade name) TOTM, manufactured by J-Plus Co., Ltd.; molecular weight 546) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition, and a paste PVC sheet was prepared and its physical properties were evaluated. The results are shown in Table 5. The obtained plastisol composition had a thickness increase of 2919% after storage at 40°C for 7 days, indicating poor long-term storage stability.

[0117] Comparative Example 9: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a phenol novolac type epoxy resin ((trade name) jER154, manufactured by Mitsubishi Chemical Corporation; viscosity 608800 mPa·s, Hansen solubility parameter (calculated value) 21.3 (J / cm) was used as a plasticizer. ３ ) １／２ We attempted to prepare a plastisol composition by mixing 90 parts by weight of () with 30 parts by weight of trioctyl trimellitate ((trade name) TOTM, manufactured by J-Plus Co., Ltd.; molecular weight 546) and kneading it at 23°C using a dissolver. However, efficient kneading was difficult due to the absorption of the plasticizer, and we were unable to prepare a plastisol composition.

[0118] Comparative Example 10: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, dimethylpolysiloxane ((trade name) kf-96-30cs, manufactured by Shin-Etsu Chemical Co., Ltd.; viscosity 30 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was used as a plasticizer. ３ ) １／２90 parts by weight of ) and 30 parts by weight of 4-tert-butylphenyl glycidyl ether ((trade name) Adekaglycirol ED-509E, manufactured by ADEKA Corporation; molecular weight 206) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition. Attempts were made to prepare a sheet by heating at 80°C for 30 minutes, but the sheet did not harden (gel) and could not be prepared. The evaluation results are shown in Table 5.

[0119] Comparative Example 11: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, an acrylic oligomer ((trade name) UP-1021, manufactured by Toagosei Co., Ltd.; viscosity 400 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was used as a plasticizer. ３ ) １／２ 90 parts by weight of ) and 30 parts by weight of trioctyl trimellitate ((trade name) TOTM, manufactured by J-Plus Co., Ltd.; molecular weight 546) were mixed and kneaded and degassed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition. Attempts were made to prepare a sheet by heating at 80°C for 30 minutes, but the sheet did not harden (gel) and could not be prepared. The evaluation results are shown in Table 5.

[0120] Comparative Example 12: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was used as a plasticizer. ３ ) １／２ 90 parts by weight of ) and 30 parts by weight of 4-tert-butylphenyl glycidyl ether ((trade name) Adekaglycirol ED-509E, manufactured by ADEKA Corporation; molecular weight 206) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition, and a paste PVC sheet was prepared and its physical properties were evaluated. The results are shown in Table 5. The obtained plastisol composition had a thickness increase of 1086% after storage at 40°C for 7 days, indicating poor long-term storage stability.

[0121] Comparative Example 13: To 100 parts by weight of the vinyl chloride-vinyl acetate copolymer obtained in Preparation Example 1, a bisphenol A type epoxy resin ((product name) Adeka Resin EP-4100E, manufactured by ADEKA Corporation; viscosity 19600 mPa·s, Hansen solubility parameter (calculated value) 20.4 (J / cm) was used as a plasticizer. ３ ) １／２ 90 parts by weight of ) and 30 parts by weight of acrylic polyol ((product name) Alphon UH-2000, manufactured by Toagosei Co., Ltd.; molecular weight 11000) were mixed and kneaded and defoamed using a dissolver at 23°C for 3 minutes to obtain a plastisol composition.

[0122] The various physical properties and sheet properties of the obtained plastisol composition were evaluated. The results are shown in Table 5. The tensile elongation was low.

[0123]

[0124] Furthermore, the entire contents of the claims, description, and abstract of Japanese Patent Application No. 2025-068567, filed on April 18, 2025, and Japanese Patent Application No. 2025-200493, filed on November 20, 2025, are incorporated herein by reference as disclosure of the specification of the present invention.

[0125] The plastisol of the present invention exhibits excellent storage stability, as well as superior processability and mechanical properties even when processed at low temperatures such as 80°C. It possesses excellent properties as a coating agent, particularly for automotive underbody coatings and automotive sealants, and therefore has high industrial value.

Claims

1. A plastisol composition comprising at least a vinyl chloride-vinyl acetate copolymer (A) having an average content of vinyl acetate polymerization units of 5 to 20% by weight, a compound (B) satisfying the following (1) and (2), and a compound (C) satisfying the following (3), wherein the total amount of compound (B) and compound (C) is 80 to 250 parts by weight per 100 parts by weight of the vinyl chloride-vinyl acetate copolymer (A), and the ratio of compound (C) to the total amount of compound (B) and compound (C) is 10 to 60% by weight. (1); 23°C, shear rate 4s －１ Viscoelasticity measured under the following conditions: (2) Viscosity of 4,000 to 500,000 mPa·s; Hasnsen solubility parameter of 16 to 22 (J / cm²). ３ ) １／２ (3) Weight-average molecular weight is 300 to 2000 2. The plastisol composition according to claim 1, characterized in that the vinyl chloride-vinyl acetate copolymer (A) is a vinyl chloride-vinyl acetate copolymer containing primary particle sizes of 0.5 to 30 μm based on volume median diameter.

3. The plastisol composition according to claim 1 or 2, characterized in that the compound (B) is one or more compounds selected from the group consisting of aromatic epoxy resins (B1), alicyclic epoxy resins (B2), and polyester compounds (B3).

4. The plastisol composition according to any one of claims 1 to 3, characterized in that the compound (C) is at least one compound selected from the group consisting of compounds having an aromatic ring and an aliphatic hydrocarbon group (C1), aliphatic ester compounds (C2), aliphatic oligomers (C3), all-aliphatic epoxy compounds (C4), and silicon oligomers (C5).

5. The plastisol composition according to any one of claims 1 to 4, characterized in that it is for low-temperature processing at a molding temperature of 70 to 90°C.

6. A plastisol composition according to any one of claims 1 to 5, characterized in that a JIS No. 3 dumbbell test specimen prepared from a 2 mm thick sheet under heating conditions of 80°C for 30 minutes has a tensile strength of 0.5 MPa or more and a tensile elongation of 50% or more, in accordance with JIS K6251.

7. The plastisol composition according to any one of claims 1 to 6, characterized in that compound (B) is an aromatic epoxy resin (B1), and compound (C) is a compound (C1) having an aromatic ring and an aliphatic hydrocarbon group.

8. The plastisol composition according to claim 7, characterized in that the aromatic epoxy resin (B1) is a bisphenol A type epoxy resin.

9. The plastisol composition according to claim 7 or 8, characterized in that the compound (C1) having an aromatic ring and an aliphatic hydrocarbon group is one or more compounds selected from the group consisting of phthalates, trimellitic acid esters, pyromellitic acid esters, and phenyl sulfonate esters.

10. A plastisol composition according to any one of 7 to 9, characterized in that a JIS No. 3 dumbbell test specimen prepared from a 2 mm thick sheet under heating conditions of 80°C for 30 minutes has a tensile strength of 0.5 MPa or more and a tensile elongation of 60% or more, in accordance with JIS K6251.

11. The plastisol composition according to any one of claims 1 to 10, further comprising one or more additives selected from the group consisting of fillers, stabilizers, antioxidants, flame retardants, lubricants, ultraviolet absorbers, colorants, adhesives, surfactants, antistatic agents, and epoxy curing agents.

12. An automotive underbody coating agent characterized by comprising the plastisol composition described in any one of claims 1 to 11.

13. An automotive sealant characterized by comprising the plastisol composition described in any one of claims 1 to 11.

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