Vinyl chloride polymer composition, its production method and uses

Abstract

To provide a polyvinyl chloride polymer composition that gives a molding that retains the flame retardancy and high heat insulation inherent in the polyvinyl chloride polymer and has excellent rigidity and heat resistance, the polyvinyl chloride polymer composition suitable for window frames and the like, and a method for efficiently producing the same.SOLUTION: A polyvinyl chloride polymer composition contains a micro-fibrillated hydrophobic cellulose fiber (A), a fibrillation agent (B1) and a polyvinyl chloride polymer (C), and optionally contains an ethylene vinyl acetate-based copolymer (D). The micro-fibrillated hydrophobic cellulose fiber (A) is modified with a C2-5 acyl group, and the fibrillation agent (B1) is at least one compound selected from the group consisting of a polyhydric alcohol with a molecular weight of 130-400 and a lactone with a molecular weight of 86-115.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a vinyl chloride polymer composition, a production method thereof, and uses thereof. In particular, the present invention relates to a vinyl chloride polymer composition that maintains flame retardancy and high thermal insulation properties and that can give a molded article having excellent rigidity, heat resistance, and environmental properties, a production method thereof, and uses thereof, such as window frames. [Background technology]

[0002] Vinyl chloride polymers and compositions thereof have been widely used in the fields of pipes, window frames, flat plates, sheets, etc., by extrusion molding or the like, because they are excellent in rigidity, weather resistance, flame retardancy, etc., and are inexpensive and highly productive.

[0003] Among these, when it comes to applications such as window frames, while it excels in terms of high insulation and moisture-proofing performance, its rigidity is only around 2000-3000 MPa. Therefore, in order to obtain the wind pressure resistance required for window frames, the frame material must be designed to be thicker and have larger external dimensions, and metal reinforcing materials must be inserted into the frame material, which increases material costs. Therefore, although it has advantages in terms of use such as insulation performance, it is a product that is difficult to meet market demands economically.

[0004] Furthermore, since the upper limit of heat resistance for vinyl chloride resins is approximately 70 to 90°C, when they are used as exterior components, they may be deformed due to solar heat. In particular, exterior components for window frames are susceptible to deformation due to exposure to sunlight. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a vinyl chloride polymer composition which maintains the flame retardancy and high heat insulating properties inherent to vinyl chloride polymers, gives a molded article having excellent rigidity and heat resistance, and is suitable for applications such as window frames, and to provide an efficient method for producing the same. [Means for solving the problem]

[0006] The present inventors have found that when a mixture of a cellulose fiber assembly modified with a specific chemical modifying group to be hydrophobic and a vinyl chloride polymer is melt-kneaded in the presence of a polyhydric alcohol or lactone having a specific molecular weight, defibration of the cellulose fiber assembly is promoted during melt-kneading, and a vinyl chloride polymer composition containing microfibrillated hydrophobic cellulose fibers is obtained. That is, it has been found that polyhydric alcohols or lactones of a specific molecular weight act as defibration promoters (defibration agents) for hydrophobized cellulosic fiber aggregates. The present invention was completed based on this finding.

[0007] The present invention relates to a vinyl chloride polymer composition, a molded article, and a method for producing a vinyl chloride polymer composition, as described in the following items. Section 1. Microfibrillated hydrophobic cellulosic fibers (A )、 A vinyl chloride polymer composition containing a defibrator (B1) and a vinyl chloride polymer (C), the microfibrillated hydrophobic cellulosic fibers (A) are modified with an acyl group having 2 to 5 carbon atoms, and the defibrating agent (B1) is at least one compound selected from the group consisting of dipropylene glycol, triethylene glycol, diglycerol, tripropylene glycol, tetraethylene glycol, polyethylene glycol (number average molecular weight 200 to 400), polyoxypropylene glycol (number average molecular weight 200 to 400), and polyoxypropylene glyceryl ether (number average molecular weight 200 to 400); the content of the microfibrillated hydrophobic cellulose fibers (A) is 1 to 40% by mass based on the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C), the content of the defibrating agent (B1) is 0.001% by mass or more and 5% by mass or less based on the total mass of the vinyl chloride polymer composition, A vinyl chloride polymer composition, wherein the content of the vinyl chloride polymer (C) is 60 to 99 mass% based on the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C). Section 2. Item 2. The vinyl chloride polymer composition according to Item 1, further comprising an ethylene-vinyl acetate copolymer (D), wherein the ethylene-vinyl acetate copolymer (D) has a vinyl acetate content of 3% by mass or more and 85% by mass or less, wherein acetyl groups of the vinyl acetate constituting the ethylene-vinyl acetate copolymer (D) are substituted with hydrogen atoms by a saponification reaction, and the saponification degree is 0% or more and 95% or less. Section 3. Item 3. The vinyl chloride polymer composition according to Item 1 or 2, wherein all or part of the vinyl chloride polymer (C) is a vinyl chloride copolymer (F) obtained by copolymerizing vinyl chloride and vinyl acetate, and the vinyl chloride copolymer (F) has a vinyl acetate content of 0.3 mass% or more and 30 mass% or less. Section 4. Item 3. The vinyl chloride polymer composition according to Item 1 or 2, further comprising a defibrating agent (B2) different from the defibrating agent (B1), wherein the defibrating agent (B2) is at least one selected from the group consisting of talc, clay, zeolite, aluminum oxide, calcium carbonate, titanium oxide, silica, magnesium oxide, and mica. Section 5. Item 3. The vinyl chloride polymer composition according to Item 1 or 2, wherein the microfibrillated hydrophobic cellulosic fibers (A) are modified with acetyl groups, and the defibrating agent (B1) is at least one selected from the group consisting of dipropylene glycol, tripropylene glycol, polyoxypropylene glycol (average molecular weight 200), and polyoxypropylene glyceryl ether (average molecular weight 250). Section 6. Item 6. The vinyl chloride polymer composition according to any one of Items 1 to 5, wherein the microfibrillated hydrophobic cellulosic fibers (A) are microfibrillated hydrophobic lignocellulose fibers (MFLC). Section 7. Item 7. A molded article made of the vinyl chloride polymer composition according to any one of items 1 to 6. Section 8. Item 7. A window frame material comprising the vinyl chloride polymer composition according to any one of Items 1 to 6. Section 9. A hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms, a defibrating agent (B1), a vinyl chloride polymer (C), and optionally an ethylene-vinyl acetate copolymer (D), the amount of the defibrating agent (B1) used is 0.1 to 5 parts by mass per part by mass of the hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms, The amount of the vinyl chloride polymer (C) used is 3 to 100 parts by mass per part by mass of the hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms; and When an ethylene-vinyl acetate copolymer (D) is used as needed, the amount of the ethylene-vinyl acetate copolymer (D) used is 0.1 to 3 parts by mass per part by mass of the hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms, and mixing the hydrophobized cellulose fiber aggregate (AP) with the mixture, and defibrating and microfibrillating the hydrophobized cellulose fiber aggregate (AP) during the mixing operation. 1. A method for producing a vinyl chloride polymer composition containing microfibrillated hydrophobic cellulose fibers (A), a vinyl chloride polymer (C), and optionally an ethylene-vinyl acetate copolymer (D), comprising: the microfibrillated hydrophobic cellulose fibers (A) are modified with an acyl group having 2 to 5 carbon atoms, The defibrating agent (B1) is at least one compound selected from the group consisting of dipropylene glycol, triethylene glycol, diglycerol, tripropylene glycol, tetraethylene glycol, polyethylene glycol (number average molecular weight 200 to 400), polyoxypropylene glycol (number average molecular weight 200 to 400), and polyoxypropylene glyceryl ether (number average molecular weight 200 to 400). A method for producing a vinyl chloride polymer composition. Section 10. Item 11. A method for producing a vinyl chloride polymer composition according to Item 10, wherein a defibrating agent (B2) different from the defibrating agent (B1) is further mixed in the step to produce a vinyl chloride polymer composition further containing a defibrating agent (B2), wherein the defibrating agent (B2) is at least one selected from the group consisting of talc, clay, zeolite, aluminum oxide, calcium carbonate, titanium oxide, silica, magnesium oxide, and mica. Section 11. (1) A hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms, a defibrating agent (B1), a vinyl chloride polymer (C), and optionally an ethylene-vinyl acetate copolymer (D), the amount of the defibrating agent (B1) used is 0.1 to 5 parts by mass per part by mass of the hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms, The amount of the vinyl chloride polymer (C) used is 3 to 100 parts by mass per part by mass of the hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms; and When an ethylene-vinyl acetate copolymer (D) is used as needed, the amount of the ethylene-vinyl acetate copolymer (D) used is 0.1 to 3 parts by mass per part by mass of the hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms, a first step of mixing the hydrophobized cellulose fiber aggregate (AP) and defibrating and microfibrillating the AP during the mixing operation; (2) A second step of removing the defibrating agent (B1) from the mixture obtained in the first step, which contains the microfibrillated hydrophobic cellulose fibers (A), the defibrating agent (B1), the vinyl chloride polymer (C), and optionally the ethylene-vinyl acetate copolymer (D), A method for producing a vinyl chloride polymer composition, wherein the microfibrillated hydrophobic cellulose fibers (A) are modified with an acyl group having 2 to 5 carbon atoms, The defibrating agent (B1) is at least one compound selected from the group consisting of dipropylene glycol, triethylene glycol, diglycerol, tripropylene glycol, tetraethylene glycol, polyethylene glycol (number average molecular weight 200 to 400), polyoxypropylene glycol (number average molecular weight 200 to 400), and polyoxypropylene glyceryl ether (number average molecular weight 200 to 400). A method for producing a vinyl chloride polymer composition. Section 12. Item 12. A method for producing a vinyl chloride polymer composition according to Item 11, wherein in the first step, a defibrating agent (B2) different from the defibrating agent (B1) is further mixed to produce a vinyl chloride polymer composition further containing a defibrating agent (B2), wherein the defibrating agent (B2) is at least one selected from the group consisting of talc, clay, zeolite, aluminum oxide, calcium carbonate, titanium oxide, silica, magnesium oxide, and mica. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a vinyl chloride polymer composition that maintains the flame retardancy and high heat insulating properties inherent to vinyl chloride polymers and that gives a molded article having excellent rigidity and heat resistance, and a method for producing the same. Furthermore, in the production method of the present invention, by making the defibrating agent (B1) present when melt-kneading the hydrophobized cellulose fiber aggregate and the vinyl chloride polymer, the hydrophobized cellulose fiber aggregate is easily microfibrillated during melt-kneading, and therefore a melt-kneaded product containing the hydrophobized MFC (i.e., the vinyl chloride polymer composition of the present invention) can be efficiently produced. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an electron microscope image of defibrated fibers in the composition produced in Example 1. [Figure 2] 1 is an electron microscope image of the defibrated raw material used in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1. Explanation of terms and abbreviations As used herein, the following terms have the following meanings:

[0011] Cellulosic fibers refer to fibers containing cellulose and / or lignocellulose that are derived from plants, microorganisms, algae, or tunicates (ascidians).

[0012] Lignocellulose is a complex hydrocarbon polymer (a mixture of natural polymers) that constitutes the cell walls of trees, and is known to be composed mainly of the polysaccharides cellulose and hemicellulose and the aromatic polymer lignin. In the present invention, lignocellulose refers to a substance composed of cellulose, hemicellulose, and lignin, regardless of the amount of lignin content or the presence or absence of chemical bonds between the cellulose, hemicellulose, and / or lignin.

[0013] Cellulosic pulp refers to a fiber aggregate made of cellulose polymers. Cellulosic pulp (CP) includes pulp that does not contain lignin (pulp made of cellulose, holo These include pulps containing cellulose (such as pulp made of cellulose) and pulp containing lignin (lignopulp). Cellulosic pulp can also be classified according to its origin as follows: cellulosic fiber aggregates isolated from whole plants or plant parts such as wood, bamboo, rice straw, and cotton (plant-derived pulp); cellulosic fiber aggregates isolated from a mixture of cellulose produced by microorganisms and microbial cells (microorganism-derived pulp); cellulosic fiber aggregates isolated from algae (algae-derived pulp); and cellulosic fiber aggregates isolated from tunicates (sea squirts) (sea squirt-derived pulp).

[0014] As used herein, hydrophobized cellulose fiber aggregate refers to pulp chemically modified with hydrophobic groups (acyl groups in the present invention). In this specification, "chemical modification" means that a substituent (chemically modified group) has been introduced in place of the hydrogen atom of the hydroxyl group of the sugar chain constituting the cellulose fiber (the hydroxyl group has been chemically modified). Therefore, the hydrophobized cellulose fiber aggregate is one aspect of chemically modified pulp (chemically modified cellulose fiber aggregate), and in the present invention, it is a hydrophobized cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms.

[0015] Chemically modified microfibrillated cellulose fiber (chemically modified MFC) means a cellulose fiber that has been chemically modified and microfibrillated. In the present invention, the chemically modified MFC is a hydrophobic MFC (a microfibrillated hydrophobic cellulose fiber (A)), that is, a cellulose fiber that has been microfibrillated and into which an acyl group having 2 to 5 carbon atoms has been introduced.

[0016] In this specification, microfibrillation means that the diameter of a fiber is on the nano order, or that the fibers present inside or on the surface of a fiber are on the nano order. Therefore, fibers that have been defibrated to a nano order diameter, fibers whose diameter at the thickest part is on the nano order or larger (for example, several μm) but whose inside or surface has been defibrated to the nano order, and fibers that are a mixture of these fibers are also considered to be microfibrillated fibers.

[0017] The following abbreviations used in this specification have the following meanings: Acyl: acyl group Ac: acetyl group LP: Lignopulp CP: Cellulosic fiber aggregate (cellulosic pulp) AcCP: A pulp in which the hydrogen atoms of some of the hydroxyl groups in the sugar chains that make up the cellulosic fibers of a cellulosic fiber aggregate (cellulosic pulp), or in the sugar chains and lignin, are substituted with acetyl groups. MFC: Microfibrillated cellulosic fibres AcylMFC: Cellulosic fiber in which the hydrogen atoms of some of the hydroxyl groups in the sugar chains that make up the fiber, or in the sugar chains and lignin, have been replaced with acyl groups, and the fiber has been microfibrillated. MFLC: Microfibrillated lignocellulosic fibers AcMFLC: Microfibrillated fibers in which the hydrogen atoms of some of the hydroxyl groups in the sugar chains that make up lignocellulosic fibers, or in the sugar chains and lignin, have been replaced with acetyl groups.

[0018] 2. Fiber raw material (defibrated raw material) used in the composition of the present invention The fiber raw material used in the composition of the present invention is a hydrophobic cellulosic fiber aggregate (AcylCP) in which the hydrogen atoms of some of the hydroxyl groups in the sugar chains that constitute the cellulosic fibers, or in the sugar chains and lignin, have been substituted with specific acyl groups.

[0019] To prepare AcylCP, cellulosic fiber aggregates derived from plants, microorganisms, algae, or urochordata (sea squirts) can be used. Among these, plant-derived cellulosic fiber aggregates are preferred because they are readily available in large quantities. Examples of raw materials for plant-derived cellulosic fiber aggregates include wood, bamboo, hemp, jute, kenaf, cotton, beet, agricultural waste, waste paper, and woven fabrics. Among these, wood-derived cellulosic fiber aggregates (also known as wood pulp) are preferred because they are readily available.

[0020] Wood pulp includes those that do not contain lignin and those that contain lignin (called lignopulp). Both can be used to produce defibrating raw materials. From the viewpoint of production costs, lignopulp is preferred.

[0021] Examples of wood that can be used as a raw material for wood pulp include wood derived from conifers such as Sitka spruce, pine (such as Abies sachalinensis and red pine), cedar, and cypress, and wood derived from broad-leaved trees such as eucalyptus and acacia. Wood pulp obtained from these is preferably used for producing defibrating raw materials.

[0022] Furthermore, among wood pulps, pulp derived from conifers, particularly lignopulp (LP) obtained from Abies sachalinensis, Akamatsu (Japanese red pine), or Sugi (Japanese cedar), is preferred because by incorporating chemically modified MFC produced using it, a vinyl chloride polymer composition having excellent strength properties and heat resistance can be obtained.

[0023] Wood pulp can be obtained by processing raw wood using mechanical pulping, chemical pulping, or a combination of mechanical and chemical pulping. Examples of such pulps include kraft pulp and mechanical pulp (MP). Examples of kraft pulp include unbleached softwood kraft pulp (NUKP), oxygen-bleached unbleached softwood kraft pulp (NOKP), and bleached softwood kraft pulp (NBKP). Examples of mechanical pulp (MP) include groundwood pulp (GP), refined GP (RGP), thermomechanical pulp (TMP), and chemithermomechanical pulp (CTMP). Pulp can also be made from deinked waste paper, recycled corrugated cardboard, magazines, copy paper, etc. One type of pulp may be used alone, or two or more types may be mixed together. Wood pulp contains lignocellulose, which is mainly composed of cellulose, hemicellulose, and lignin. In this specification, pulp from which lignin has not been completely removed and even a small amount of lignin is present in the pulp is referred to as lignopulp. Therefore, all pulp obtained by the above-mentioned various pulping methods and containing detectable lignin, even in small amounts, is included in the lignopulp category.

[0024] Lignopulp is advantageous in terms of production cost because it requires fewer production steps, has a good yield from raw materials (e.g., wood), requires fewer chemicals, and can be produced with less energy than lignin-free cellulose fibers or pulp. Therefore, lignopulp can be advantageously used in the present invention. The amount of lignin contained can be quantified by the Klason method.

[0025] In the present invention, wood pulp is previously subjected to processes such as maceration, beating, and defibration using a refiner or beater, or a combination of these, and the wood pulp that can be used has a Canadian Standard Freeness (CSF) value (freeness) after the process of typically 40 mL to 500 mL, preferably 40 mL to 300 mL, and more preferably 40 mL to 200 mL.

[0026] Microbial cellulosic fibers can be obtained, for example, from microbial pulp obtained by removing proteins and other impurities from a mixture of cellulose fibers and bacterial cells recovered from a culture medium in which acetic acid bacteria are cultured. Microbial cellulosic fibers are usually composed of nano-level cellulose fibers intertwined in a network, and can be used as a raw material for hydrophobic cellulosic fiber aggregates.

[0027] The defibrating raw material used in the present invention is characterized in that the hydrogen atoms of some of the hydroxyl groups in the sugar chains or sugar chains and lignin that make up the cellulosic fibers are substituted with a specific acyl group A (i.e., an acyl group having 2 to 5 carbon atoms) described below, making them more hydrophobic than before the substitution. In this specification, the substitution of hydrogen atoms of some of the hydroxyl groups in the sugar chains or sugar chains and lignin that make up the cellulosic fibers is also referred to as "chemical modification," and the substituent introduced in place of the hydrogen atoms of the hydroxyl groups is sometimes referred to as a "chemically modified group."

[0028] By selecting a specific acyl group A as a substituent for the hydrogen atoms of some of the hydroxyl groups in the defibrating raw material, the defibrating raw material chemically modified with such a substituent not only has improved thermal stability, but also becomes more susceptible to microfibrillation during the defibrating process by the defibrating agent used in the present invention, and is easily defibrated into chemically modified MFC. This is thought to be because the hydrogen bonds between hydroxyl groups originally present on the surface of cellulosic fibers are partially lost by acylation in the defibrating raw material, and the action of the defibrating agent makes it more susceptible to microfibrillation during the defibrating process.

[0029] Furthermore, this chemically modified MFC is also hydrophobicized by being chemically modified with a specific acyl group A, and therefore is more hydrophobic than original cellulosic fibers, and therefore has a high affinity with the vinyl chloride polymer (C), making it more likely to be uniformly dispersed in the resin. Therefore, the molded article of the present invention produced from a composition containing the chemically modified MFC produced using the defibrating agent (B1) and the vinyl chloride polymer (C) has excellent strength properties and heat resistance.

[0030] The defibrating raw material has an acyl group A as a substituent. The defibrating raw material is defibrated using a defibrating agent (B1), and the resulting cellulose-based fibers modified with the acyl group A and microfibrillated (these cellulose-based fibers are also referred to as "Acyl(A)MFC") have a high affinity for vinyl chloride polymers and can be uniformly dispersed in the vinyl chloride polymers. Furthermore, when the defibrated raw material is chemically modified with the acyl group A, not only can the high crystallinity of the cellulose originally present in the raw pulp be maintained during preparation, but this high crystallinity can also be maintained in the Acyl(A) MFC produced by microfibrillating the above-mentioned defibrated raw material.

[0031] Specific examples of the acyl group A having 2 to 5 carbon atoms include an acetyl group, an ethylcarbonyl group, an n-propylcarbonyl group, and a pivaloyl group. These are preferred because the acylating agent used for acylation is available at lower cost than other acylating agents. Among these, an acetyl group is more preferred. From the above, as the microfibrillated hydrophobic cellulose fiber (A), hydrophobic lignocellulose fiber (AcylMFLC) that has been microfibrillated and modified with an acyl group A is preferred, and hydrophobic lignocellulose fiber (AcMFLC) that has been modified with an acetyl group is particularly preferred.

[0032] 3. Degree of substitution of the hydrophobic cellulose fiber assembly used in the present invention The degree of modification with acyl groups (also called the degree of substitution or DS) in the hydrophobized cellulose fiber aggregate (hydrophobized CP, specifically AcylCP) used in the present invention is expressed as the degree to which the hydrogen atoms of the hydroxyl groups present in one unit (repeating unit) of the cellulose polymer that constitutes the cellulose fiber aggregate are replaced by the above-mentioned substituent. When the hydrophobized cellulose fiber aggregate is a hydrophobized lignocellulose fiber aggregate (hydrophobized LP, specifically AcLP), the degree of substitution can be calculated, for example, based on the description in paragraphs 0253 to 0261 of JP 2018-150414, by replacing "ASA" in these paragraphs with an acyl group (e.g., an acetyl group) and "apparent mass" with "formula weight of unmodified lignocellulose (formula weight of repeating unit)."

[0033] When the cellulosic fiber assembly is composed entirely of cellulose (in the case of cellulose), the repeating units are glucopyranose residues, and the number of hydroxyl groups per unit is three, so the upper limit of the degree of substitution is three. On the other hand, when the cellulosic fiber assembly is lignocellulose, the lignocellulose contains hemicellulose and lignin in addition to cellulose. The number of hydroxyl groups in the xylose residues in the xylan and the galactose residues in the arabinogalactan contained in the hemicellulose is two, and the number of hydroxyl groups in standard lignin residues is also two, which is less than three. Therefore, the upper limit of the degree of substitution in a lignocellulose fiber assembly (lignopulp) is less than 3. The upper limit of this degree of substitution is about 2.7 to 2.8, depending on the contents of hemicellulose and lignin contained in the lignocellulose fiber (lignopulp).

[0034] As mentioned above, the degree of substitution (DS) depends on the hemicellulose or lignin content in the cellulosic fiber assembly. However, for both the hydrophobized cellulosic assembly (CP) used in the present invention and the chemically modified microfibrillated cellulosic fibers (chemically modified MFC) obtained by defibrating it, the degree of substitution (DS) with acyl groups is preferably about 0.2 to 2.0. The degree of substitution (DS) is more preferably about 0.3 to 1.5, and even more preferably about 0.3 to 1.4. In particular, when the acyl group is an acetyl group, the degree of substitution (DS) is more preferably about 0.4 to 1.3. Chemically modified MFC having a DS within the above range has an appropriate degree of crystallinity and SP (solubility parameter), and therefore is uniformly dispersed in the matrix (vinyl chloride polymer), and a melt-kneaded composition containing such chemically modified MFC has excellent physical properties. The degree of substitution (DS) can be analyzed by various analytical methods such as neutralization titration, FTIR, and two-dimensional NMR ( 1 H and 13 C-NMR).

[0035] 4. Fiber size and observation methods In the present invention, microfibrillated cellulose fiber (MFC) does not only mean fibers in which all of the fibers constituting the above-mentioned cellulose fiber assembly have been microfibrillated to nanometer-order diameters, but also means cellulose fiber containing at least a microfibrillated portion, and refers to the above-mentioned cellulose fiber having a nanometer-order diameter or the diameter of the fibers inside or on the surface of the fiber. The same applies to chemically modified MFC.

[0036] The fiber diameters of the microfibrillated cellulose fibers (MFC) and chemically modified microfibrillated cellulose fibers (chemically modified MFC) referred to in this specification are each approximately several tens of nm to several μm.

[0037] When taking an SEM photograph of the chemically modified MFC in the vinyl chloride polymer composition, it is preferable to elute the vinyl chloride polymer in the vinyl chloride polymer composition with a solvent (e.g., tetrahydrofuran) in which the vinyl chloride polymer is soluble but the chemically modified MFC is insoluble, and then take an SEM photograph of the remaining chemically modified MFC.

[0038] 5. Method for producing the hydrophobic cellulose fiber aggregate (fibrillation raw material) used in the present invention The method for preparing defibrated raw materials (acylation reaction) will be explained.

[0039] The modification of the raw material pulp with acyl groups can be carried out by a known method, for example, by reacting the raw material pulp with an acylating agent having an acyl group in a solvent while stirring or while standing. Examples of the acylating agent include carboxylic acid anhydrides, carboxylic acid halides such as carboxylic acid chlorides, and vinyl carboxylates. Among these, vinyl carboxylates are preferred because by-products can be easily removed from the reaction system.

[0040] In chemical modification with acyl groups, the use of the corresponding vinyl carboxylic acid ester (vinyl carboxylate) as the acylating agent reduces the coloration of the chemically modified cellulosic fibers obtained by acylation, and in turn reduces the coloration of the melt-kneaded composition (composite) produced by compounding these fibers. Of course, acylating agents other than vinyl carboxylate esters (e.g., carboxylic acid chlorides, carboxylic acid anhydrides) can also be used. In this case, it is preferable to add an organic or inorganic base to capture the acid (hydrochloric acid, carboxylic acid, etc.) by-produced in the acylation reaction during the reaction. However, the salts produced are likely to be mixed into the acylated cellulose fiber, which may cause discoloration of the target acylated cellulose fiber, making careful purification necessary in this case. Among these acylating agents, it is preferable to use an acylating agent having an acyl group selected from the group consisting of an acetyl group, a propionyl group, and a pivaloyl group, since this allows the production of acylated microfibrillated cellulosic fibers with particularly good thermal stability. Specific examples of the acylating agent having an acyl group include vinyl acetate, acetic anhydride, vinyl pivalate, and pivalic anhydride. Among these, acylating agents having an acetyl group (vinyl acetate and acetic anhydride) are preferred from the viewpoint of production costs.

[0041] The acylation reaction is preferably carried out in a solvent in the presence of a base. A solvent that does not react with the acylating agent, easily swells the acylation raw material, and can be easily removed from the reaction system after the reaction with the acylation raw material is preferred. Examples of such solvents include polar aprotic solvents such as N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), and dioxane. The amount of solvent used is approximately 20 to 200 parts by mass per part by mass of the acylation raw material in a dry state.

[0042] However, if the acylating agent is liquid at the reaction temperature and the by-products of the reaction are also liquid, the acylating agent and the by-products can be used as a solvent. In this case, the amount of solvent used is about 0 to 3 parts by mass per 1 part by mass of the acylation raw material. For example, when acylation (i.e., acetylation) is performed using acetic anhydride as the acylating agent, the amount of solvent used is about 0 (no solvent) to 3 parts by mass per 1 part by mass of the acylation raw material.

[0043] Examples of the base include amines such as pyridine and dimethylaniline, alkali metal salts of acetic acid such as potassium acetate and sodium acetate, and alkali metal carbonates such as lithium carbonate, potassium carbonate and sodium carbonate. The amount of the base used is about 0.1 to 1 mole per mole of hydroxyl groups in the acylation raw material.

[0044] The amount of acylating agent used relative to the raw pulp can be adjusted appropriately depending on the water content of the raw pulp, the desired degree of acylation (degree of substitution, DS), etc., but is usually about 0.5 to 2 times the number of moles of hydroxyl groups present in the raw pulp. When the raw pulp contains water, it is preferable to use a larger amount of acylating agent than the above, taking into account the amount of acylating agent consumed by the water.

[0045] The degree of acylation (degree of substitution, DS) during the acylation reaction can be determined by taking an amount required for analysis from the reaction mixture, removing unreacted acylating agent, acylation by-products, etc. by washing, extraction, etc., measuring the FTIR spectrum, and quantifying the result using a pre-prepared calibration curve. Therefore, the reaction is stopped when the desired DS is reached, and the reaction mixture is subjected to conventional purification procedures such as filtration, washing, and extraction, to obtain an acylated cellulose fiber aggregate (acylated pulp) having the desired DS.

[0046] The reaction temperature is usually about 10 to 130°C, and preferably about 20 to 125°C.

[0047] The reaction time is usually about 2 to 24 hours when acylation of raw material pulp derived from wood, and usually about 4 to 100 hours when acylation of raw material pulp derived from microorganisms.

[0048] 6. Defibrator (B1) The defibrating agent (B1) used in the present invention is at least one compound selected from polyhydric alcohols having a molecular weight of 130-400 and lactones having a molecular weight of 86-115.

[0049] The molecular weight of the defibrating agent (B1) referred to in this specification refers to the molecular weight of the compound when it is a single compound, and refers to the number average molecular weight of the mixture when it is a mixture of polymers or oligomers.

[0050] The polyhydric alcohol of the defibrating agent (B1) is preferably a polypropylene glycol-based diol (hereinafter also referred to as a "PPG-based diol"). Examples of PPG-based diols include dipropylene glycol, tripropylene glycol, polyoxypropylene glycol having a number-average molecular weight of 200, polyoxypropylene glycol having a number-average molecular weight of 400, polyether polyols obtained by addition polymerization of propylene oxide (hereinafter also referred to as "PO") to a dihydric alcohol, and polyether polyols obtained by addition polymerization of PO and an alkylene oxide other than PO (such as ethylene oxide (hereinafter also referred to as "EO")). The addition polymerization of PO and another alkylene oxide may be random addition polymerization or block addition polymerization. The above polyhydric alcohols can be used alone or in combination of two or more.

[0051] Examples of the dihydric alcohol include dihydric alcohols having 2 to 4 carbon atoms, such as ethylene glycol, propylene glycol, 1,3-butanediol, and 1,4-butanediol. PPG diols have structural isomers depending on the mode of addition polymerization of PO, and the PPG diols referred to in this specification include each of these isomers and mixtures thereof. The molecular weight of the PPG diol is not particularly limited as long as it is in the range of 130 to 400, but is preferably 130 to 350, more preferably 130 to 300, and particularly preferably 150 to 250.

[0052] As the polyhydric alcohol for the defibrating agent (B1), addition polymers of ethylene oxide (EO) (addition polymers of 3 to 8 EO units) having a molecular weight of 130 to 400 are also preferred. Examples of addition polymers of EO include triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, octaethylene glycol, and mixtures thereof. A mixture of addition polymers of EO with a number average molecular weight of 200 is called PEG200, and a mixture with a number average molecular weight of 400 is called PEG400.

[0053] As the polyhydric alcohol for the defibrating agent (B1), glycerin derivatives and mixtures of glycerin derivatives having a molecular weight of 130 to 400 can also be used. Specific examples of these glycerin derivatives include glycerin dimers (diglycerol) and products obtained by addition polymerization of PO with glycerin (polyoxypropylene glyceryl ether). Polyoxypropylene glyceryl ethers have structural isomers depending on the mode of addition polymerization of PO, and the term "polyoxypropylene glyceryl ether" as used herein encompasses these structural isomers and mixtures thereof. A preferred polyoxypropylene glyceryl ether is polyoxypropylene glyceryl ether (number average molecular weight 250).

[0054] Among the polyhydric alcohols for the defibrating agent (B1), from the viewpoints of defibration ability and mechanical strength when formed into a molded article, at least one polyhydric alcohol selected from the group consisting of dipropylene glycol, triethylene glycol, diglycerol, tripropylene glycol, tetraethylene glycol, polyethylene glycol (number average molecular weight 200 to 400), polyoxypropylene glycol (number average molecular weight 200 to 400), and polyoxypropylene glyceryl ether (number average molecular weight 200 to 400) is preferred, and at least one polyhydric alcohol selected from the group consisting of dipropylene glycol, triethylene glycol, diglycerol, tripropylene glycol, tetraethylene glycol, polyoxypropylene glycol (number average molecular weight 200), polyoxypropylene glycol (number average molecular weight 400), polyoxypropylene glyceryl ether (number average molecular weight 250), and polyoxypropylene glycol (number average molecular weight 400) is more preferred.

[0055] Among these, at least one polyhydric alcohol selected from the group consisting of dipropylene glycol, tripropylene glycol, polyoxypropylene glycol (number average molecular weight 200) and polyoxypropylene glyceryl ether (number average molecular weight 250) is particularly preferred from the standpoint of defibration ability.

[0056] The polyhydric alcohol used as the defibrating agent (B1) has a flash point of 100°C or higher, and is therefore preferred from the standpoint of disaster prevention and safety during the production of the composition of the present invention.

[0057] The defibrating agent (B1) can be a lactone having a molecular weight of 86 to 115. Among these, δ-valerolactone and ε-caprolactone are preferred in terms of defibrating ability and safety in use.

[0058] If a large amount of the defibrating agent (B1) remains in the vinyl chloride polymer composition, the strength properties of a molded body using this resin composition as a molded body material tend to decrease. Therefore, it is preferable to remove the defibrating agent (B1) remaining in the resin composition from the molded body material or the molded body.

[0059] The defibrating agent (B1) (a polyhydric alcohol having a molecular weight of 130 to 400 and a lactone having a molecular weight of 86 to 115) can be removed easily and preferably by vaporizing and separating it from the molded body material or molded body by heating under reduced pressure (for example, to 125 to 280°C), since the boiling point of the defibrating agent (B1) at room temperature and atmospheric pressure is approximately 290°C or less.

[0060] The above dipropylene glycol, tripropylene glycol, polyoxypropylene glycol (average molecular weight 200), polyoxypropylene glyceryl ether (average molecular weight 250), and polyoxypropylene glycol (average molecular weight 400) each have structural isomers, and these isomers or mixtures thereof are also included in the defibrating agent (B1) of the present invention.

[0061] The content of the defibrating agent (B1) is preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.01% by mass or more and 3% by mass or less, based on the total mass of the vinyl chloride polymer composition.

[0062] The vinyl chloride polymer composition may contain a defibrating agent (B2) different from the defibrating agent (B1). The defibrating agent (B2) is used in combination with the defibrating agent (B1) to improve defibration properties. The defibrating agent (B2) is preferably at least one filler selected from the group consisting of talc, clay, zeolite, aluminum oxide, calcium carbonate, titanium oxide, silica, magnesium oxide, and mica.

[0063] The addition of a defibrating agent (B2) to the raw material for the vinyl chloride polymer composition makes the defibrating raw material even easier. The defibrating agent (B2) may be used by adding it to the defibrating raw material simultaneously with the defibrating agent (B1), or before or after the defibrating agent (B1).

[0064] When the defibrating agent (B2) is added, the blending ratio of the defibrating agent (B2) is preferably 0.001 to 0.5 parts by mass, more preferably 0.01 to 0.1 parts by mass, per 1 part by mass of the vinyl chloride polymer composition.

[0065] 7. Vinyl chloride polymers The vinyl chloride polymer (C) in the present invention may be a homopolymer of vinyl chloride, a copolymer of vinyl chloride and another vinyl monomer copolymerizable with vinyl chloride, or a partially crosslinked vinyl chloride polymer obtained by copolymerization of vinyl chloride, if necessary, another copolymerizable vinyl monomer, and a polyfunctional monomer.

[0066] Examples of copolymers of vinyl chloride with other vinyl monomers copolymerizable with vinyl chloride include copolymers of vinyl chloride with at least one other vinyl monomer copolymerizable with vinyl chloride selected from the group consisting of α-monoolefin monomers such as ethylene, propylene, and butylene; vinyl esters such as vinyl acetate and vinyl propionate; alkyl vinyl ethers such as methyl vinyl ether and cetyl vinyl ether; styrene derivatives such as styrene and α-methylstyrene; (meth)acrylic acid esters such as n-butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate; vinyl cyanides such as acrylonitrile and methacrylonitrile; N-substituted maleimides such as cyclohexylmaleimide and phenylmaleimide; and vinylidenes such as vinylidene chloride.

[0067] Furthermore, examples of partially crosslinked vinyl chloride polymers obtained by copolymerization of vinyl chloride with a polyfunctional monomer include copolymers of vinyl chloride with at least one polyfunctional monomer copolymerizable with vinyl chloride, such as polyfunctional allyl compounds such as diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl fumarate, diallyl adipate, and triallyl cyanurate; polyfunctional vinyl ethers such as ethylene glycol divinyl ether and octadecane divinyl ether; and polyfunctional (meth)acrylates such as 1,3-butylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate, and are vinyl chloride polymers having a partially crosslinked structure.

[0068] The average degree of polymerization of the vinyl chloride polymer (C) is preferably 600 or more and 3000 or less. By setting it in this range, it is possible to achieve a good balance of moldability of the mixture with the present defibrating raw material. Here, when the average degree of polymerization of the vinyl chloride polymer (C) is in the range of 700 or more and 2000 or less, it is possible to achieve a better balance of moldability of the mixture with the present defibrating raw material.

[0069] The method for producing the vinyl chloride polymer (C) is not particularly limited and may be any of suspension polymerization, emulsion polymerization, solution polymerization, bulk polymerization, etc., but suspension polymerization is preferred because it produces less residual monomer.

[0070] The suspension polymerization method for producing the vinyl chloride polymer (C) is well known, and any known method may be used without any particular limitation. In addition, when producing the vinyl chloride polymer by a suspension polymerization method such as emulsion polymerization, solution polymerization, or bulk polymerization, a known method may also be used.

[0071] 8. Ethylene vinyl acetate copolymer (D) The vinyl chloride polymer composition of the present invention preferably further contains an ethylene-vinyl acetate copolymer (D) which is a copolymer of a vinyl ester monomer and an ethylene monomer, It is more preferable that the content of vinyl acetate constituting the vinyl chloride copolymer is 3% by mass or more and 85% by mass or less (hereinafter also referred to as requirement (d)), and that the acetyl groups of the vinyl acetate constituting the ethylene-vinyl acetate copolymer (D) are substituted with hydrogen atoms by a saponification reaction, with a saponification degree of 0% or more and 95% or less (hereinafter also referred to as requirement (e)).

[0072] Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristylates, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylate, vinyl pivalate, vinyl octylate, vinyl monochloroacetate, vinyl adipate, vinyl methacrylate, vinyl crotonate, vinyl sorbate, vinyl benzoate, vinyl cinnamate, and vinyl versate. Among these, a homopolymer of vinyl acetate is preferred.

[0073] The vinyl acetate content constituting the ethylene-vinyl acetate copolymer (D) is 3% by mass or more and 85% by mass or less, and preferably 15% by mass or more and 50% by mass or less, as required by the above requirement (d). If the vinyl acetate content is 3% by mass or more, the compatibility with the defibrating raw material of the present invention is improved, and if it is 85% by mass or less, the strength properties and heat resistance of the molded body of the present invention are improved. Furthermore, as per the requirement (e), the ethylene vinyl acetate copolymer has a degree of saponification of 0% or more and 95% or less, preferably 0% or more and 90% or less. If the degree of saponification is 95% or less, it can exhibit compatibility with the present defibrated raw material. In terms of the strength characteristics and heat resistance of the molded article of the present invention, the content of the ethylene vinyl acetate copolymer (D) is preferably 0.3 mass % or more and 40 mass % or less, and particularly preferably 0.5 mass % or more and 30 mass % or less.

[0074] The vinyl chloride polymer (C) in the present invention is a vinyl chloride copolymer (E) (hereinafter also referred to as vinyl chloride copolymer (E)) in which all or a part (preferably 10% by mass or more and 90% by mass or less) of vinyl chloride is graft-polymerized onto an ethylene-vinyl acetate-based copolymer, and the ethylene-vinyl acetate-based copolymer constituting the vinyl chloride-based copolymer (E) is preferably an ethylene-vinyl acetate-based copolymer (D) with a content of 0.3% by mass or more and 40% by mass or less, from the viewpoint of the defibration property of the present defibration raw material and the strength properties and heat resistance of the molded body of the present invention. Furthermore, the vinyl chloride polymer (C) in the present invention is a vinyl chloride copolymer (F) (hereinafter also referred to as vinyl chloride copolymer (F)) in which all or a part (preferably 10% by mass or more and 90% by mass or less) of vinyl chloride and vinyl acetate are copolymerized, and it is preferable that the content of vinyl acetate constituting the vinyl chloride copolymer (F) is 0.3% by mass or more and 30% by mass or less from the viewpoint of the defibration property of the present defibration raw material and the strength properties and heat resistance of the molded body of the present invention.

[0075] 9. Vinyl chloride copolymer (E) The vinyl chloride copolymer (E) in the present invention is a graft copolymer obtained by graft polymerizing vinyl chloride onto the ethylene-vinyl acetate copolymer (D). There are no particular limitations on the vinyl chloride copolymer (E), but polymers with various properties can be obtained depending on the type of ethylene-vinyl acetate copolymer used and the vinyl acetate content.

[0076] In terms of compatibility with the defibrating raw material of the present invention, it is preferable that the ethylene vinyl acetate copolymer constituting the vinyl chloride copolymer (E) used in the present invention satisfies the requirements (d) and (e) above, and in terms of the strength characteristics and heat resistance of the molded body of the present invention, the content of the ethylene vinyl acetate copolymer is preferably 0.3 mass% or more and 40 mass% or less, and particularly preferably 0.5 mass% or more and 30 mass% or less.

[0077] 10. Vinyl chloride copolymer (F) The vinyl chloride copolymer (F) of the present invention can be obtained by copolymerizing vinyl chloride monomer and vinyl acetate monomer in an appropriate ratio. In terms of compatibility with the present fibrillation raw material, the vinyl chloride copolymer (F) used in the present invention preferably has a vinyl acetate content of 0.3 mass% or more and 30 mass% or less, and particularly preferably 0.5 mass% or more and 25 mass% or less.

[0078] 11. Method for defibrating defibrated raw material and method for producing a composition containing defibrated chemically modified microfibrillated cellulosic fibers The defibrating raw material can be defibrated by adding the defibrating raw material together with the defibrating agent (B1) to the vinyl chloride polymer (C), and subjecting the mixture to defibrating treatment such as stirring and kneading. Alternatively, the defibrating raw material can be defibrated by adding the defibrating raw material together with the defibrating agent (B1) to a defibrating medium (water or a mixed solvent of water and a water-soluble organic solvent, or an organic solvent in which the chemically modified cellulose fiber and the vinyl chloride polymer (C) are insoluble), and then subjecting the defibrating raw material to defibration treatment such as stirring and kneading while dispersed in the defibrating medium.

[0079] The amount of the defibrating raw material used in the defibrating treatment can be preferably 1 to 30 mass %, more preferably 3 to 25 mass %, based on the total mass of the vinyl chloride polymer (C) in the vinyl chloride polymer composition. The amount of the defibrating agent (B1) used can be preferably 0.1 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, per part by mass of the chemically modified cellulosic fibers.

[0080] The amount of vinyl chloride polymer (C) used in the defibration treatment is preferably 3 to 100 parts by mass, more preferably 4 to 30 parts by mass, and particularly preferably 10 to 30 parts by mass, per part by mass of the chemically modified cellulosic fibers.

[0081] The amount of defibrating medium used in the defibrating treatment can be preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, per 1 part by mass of the chemically modified cellulosic fibers.

[0082] When the defibrating agent (B2) is used in the defibrating treatment, the amount of the defibrating agent (B2) used can be preferably 0.01 to 1 part by mass, more preferably 0.03 to 0.5 parts by mass, per part by mass of the vinyl chloride polymer (C).

[0083] When an ethylene-vinyl acetate copolymer (D) is used in the defibration treatment, the amount of the ethylene-vinyl acetate copolymer (D) used is preferably 0.1 to 3 parts by mass, more preferably 0.3 to 2 parts by mass, per 1 part by mass of the chemically modified cellulosic fiber.

[0084] When a composite containing a resin and chemically modified cellulosic fibers is produced by a melt-kneading method, it is efficient to carry out the defibration treatment using a single-screw or multi-screw kneader.

[0085] As the defibrating agent, defibrating agent (B1) is used, but from the standpoint of strength characteristics and material cost, it is preferable to use defibrating agent (B1) in combination with an inorganic filler, i.e., defibrating agent (B2), rather than using only defibrating agent (B1).

[0086] The defibrating agent (B1) used may be contained in the vinyl chloride polymer composition or may be removed. From the viewpoint of the strength characteristics of the formed molded article, it is preferable to remove the defibrating agent (B1) from the vinyl chloride polymer composition. However, it is not necessary to completely remove the defibrating agent (B1); it is sufficient to remove it to the extent that it does not affect the physical properties of the resulting vinyl chloride polymer composition. Even if the amount of defibrating agent (B1) remaining in the vinyl chloride polymer composition is small, by analyzing and detecting it, it is possible to know that the vinyl chloride polymer composition was produced by the production method of the present invention, which is convenient for product tracing.

[0087] The amount of the defibrating agent (B1) remaining in the vinyl chloride polymer composition is 0.001 to 5 mass %, preferably 0.01 to 3 mass %, based on the total amount of the vinyl chloride polymer composition. Molded articles made from the vinyl chloride polymer composition containing this amount of defibrating agent (B1) have excellent flame retardancy, heat insulation, strength properties, and heat resistance.

[0088] The following methods I to III can be mentioned as production methods of the present invention for vinyl chloride polymer compositions containing chemically modified microfibrillated cellulose fibers (chemically modified MFC).

[0089] Method I is a method for producing a vinyl chloride polymer composition containing microfibrillated hydrophobic cellulose fibers (A) and a vinyl chloride polymer (C), which comprises the steps of mixing a hydrophobic cellulose fiber aggregate (AcylCP, hereinafter also referred to as AP), a defibrating agent (B1), and a vinyl chloride polymer (C), and defibrating and microfibrillating the cellulose fiber aggregate (AP) during this mixing operation.

[0090] Specifically, the method for producing a vinyl chloride polymer composition containing microfibrillated hydrophobic cellulose fibers (A) and a vinyl chloride polymer (C) includes a step of mixing a hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms, a defibrating agent (B1), and a vinyl chloride polymer (C), and defibrating and microfibrillating the hydrophobic cellulose fiber assembly (AP) during this mixing operation, wherein the microfibrillated hydrophobic cellulose fibers (A) are modified with an acyl group having 2 to 5 carbon atoms, and the defibrating agent (B1) is at least one compound selected from the group consisting of polyhydric alcohols having a molecular weight of 130 to 400 and lactones having a molecular weight of 86 to 115.

[0091] Method II is a method in which a defibrating agent (B1), a hydrophobic cellulose fiber aggregate (AP), and a vinyl chloride polymer (C) are mixed to defibrate and composite the hydrophobic cellulose fiber aggregate (AP), and then the defibrating agent (B1) is removed to produce a vinyl chloride copolymer composition containing microfibrillated hydrophobic cellulose fibers (A) and a vinyl chloride polymer (C).

[0092] For more details, (1) a first step of mixing a hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms, a defibrating agent (B1), and a vinyl chloride polymer (C), and defibrating and microfibrillating the hydrophobic cellulose fiber assembly (AP) during this mixing operation; (2) A second step of removing the defibrating agent (B1) from the mixture obtained in the first step, which contains the microfibrillated hydrophobized cellulosic fibers (A), the defibrating agent (B1), and the vinyl chloride polymer (C), A method for producing a vinyl chloride polymer composition containing microfibrillated hydrophobic cellulose fibers (A) and a vinyl chloride polymer (C), comprising: This is a method for producing a vinyl chloride polymer composition, wherein the microfibrillated hydrophobic cellulose fibers (A) are modified with acyl groups having 2 to 5 carbon atoms, and the defibrating agent (B1) is at least one compound selected from the group consisting of polyhydric alcohols having a molecular weight of 130 to 400 and lactones having a molecular weight of 86 to 115.

[0093] Method III is a method in which a hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms is defibrated and then composited with a vinyl chloride polymer (C) to produce a vinyl chloride polymer composition containing microfibrillated hydrophobic cellulose fibers (A) and a vinyl chloride polymer (C).

[0094] For more details, (1) a first step of producing microfibrillated hydrophobic cellulose fibers (A) by defibrating a hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms using a defibrating agent (B1); and (2) A second step of mixing the microfibrillated hydrophobic cellulose fibers (A) obtained in the first step with a vinyl chloride polymer (C). The present invention relates to a method for producing a vinyl chloride polymer composition containing microfibrillated hydrophobic cellulosic fibers (A) and a vinyl chloride polymer (C), the method comprising the steps of:

[0095] The defibration and microfibrillation of the defibrated raw material in the above-mentioned Method III can be carried out, for example, by making the defibrated raw material into a suspension or slurry and using known means such as mechanical grinding or beating using a refiner, high-pressure homogenizer, grinder, single-screw or multi-screw kneader (preferably a multi-screw kneader), bead mill, etc. In the above-mentioned Method III, if the defibrating raw material is defibrated and microfibrillated in the first step using a single-screw or multi-screw kneader, and the mixing in the second step is carried out using the single-screw or multi-screw kneader used in the first step, then the vinyl chloride polymer composition can be produced efficiently using a single type of equipment.

[0096] Of the above-mentioned production methods, Methods I and II are useful because they involve mixing the defibrating raw material, the defibrating agent (B1), and the vinyl chloride polymer (C), and optionally the ethylene-vinyl acetate copolymer (D), by melt kneading, and defibrating the defibrating raw material during the kneading operation, thereby enabling a vinyl chloride polymer composition containing hydrophobic MFC (microfibrillated hydrophobic cellulose fiber (A)) to be obtained by a simple operation.

[0097] The vinyl chloride polymer composition of the present invention contains microfibrillated hydrophobic cellulose fibers ((A); hydrophobic MFC) that have excellent dispersibility in resins and that have been easily defibrated from a defibrating raw material by the defibrating agent (B1). This hydrophobic MFC is excellent in terms of ease of production and dispersibility in vinyl chloride polymer compositions because the hydrogen atoms of some of the hydroxyl groups in the sugar chains that make up the cellulosic fibers of the MFC have been modified with acyl groups having 2 to 5 carbon atoms. Specific examples of such acyl groups include acetyl, ethylcarbonyl (also known as propionyl), n-propylcarbonyl (also known as butanoyl), and pivaloyl. Among these acyl groups, modified MFCs with an acyl group selected from the group consisting of an acetyl group, an ethylcarbonyl group, and a pivaloyl group have particularly good thermal stability and favorable dispersibility in vinyl chloride polymer compositions. Of these, the acetyl group is most preferred from the standpoints of ease of production and production costs. Two or more types of chemically modified MFCs can be combined (used in combination) and contained in the vinyl chloride polymer composition of the present invention. By using two or more types of chemically modified MFCs in combination, these chemically modified MFCs can be well dispersed in the vinyl chloride polymer composition.

[0098] In the above methods I to III, it is preferable to further mix an ethylene-vinyl acetate copolymer (D) in the step of mixing the hydrophobic cellulose fiber aggregate or the microfibrillated hydrophobic cellulose fibers with the resin.

[0099] By mixing the ethylene-vinyl acetate copolymer (D), the mixing state of the chemically modified MFC and the vinyl chloride polymer (C) is improved, and as a result, the strength characteristics and heat resistance of the molded article of the present invention made of the vinyl chloride polymer composition are improved.

[0100] When the vinyl chloride polymer composition of the present invention contains an ethylene-vinyl acetate copolymer (D), the content of the ethylene-vinyl acetate copolymer (D) in the composition can be preferably 0.1 to 5 parts by mass, more preferably 0.5 to 5 parts by mass, per part by mass of the chemically modified MFC (A) contained.

[0101] In the above-mentioned Methods I to III, in the step of mixing the hydrophobic cellulose fiber aggregate or the microfibrillated hydrophobic cellulose fibers with the resin, it is preferable to further mix the defibrating agent (B2) different from the defibrating agent (B1) in terms of strength properties and material costs.

[0102] In the above-mentioned production methods and the vinyl chloride polymer composition of the present invention, the vinyl chloride polymer (C) used is preferably one or more types of vinyl chloride polymer (C) (for example, a homopolymer of vinyl chloride, the vinyl chloride polymer (E), the vinyl chloride polymer (F), etc.).

[0103] In each of the above-mentioned production methods, the melt-kneading step carried out during the mixing operation of the various raw materials is a step in which the defibrating raw material and the vinyl chloride polymer (C) are melt-kneaded together, and the defibrating raw material is defibrated into chemically modified microfibrillated cellulose fibers (chemically modified MFC) in the molten vinyl chloride polymer (C), thereby producing a vinyl chloride polymer composition (melt-kneaded composition).

[0104] When the melt-kneaded composition contains additives other than the defibrating agent, it is preferable to add them in the mixing step of the raw materials to be melt-kneaded or in this melt-kneading step, and melt-knead both the defibrating material and the vinyl chloride polymer (C).

[0105] The heating temperature in the melt-kneading step is preferably 90°C to 200°C, more preferably 140°C to 190°C, in order to uniformly mix the chemically modified MFC and the vinyl chloride polymer (C).

[0106] In this melt-kneading step, the defibrating raw material is defibrated and microfibrillated by the shear stress during kneading and the action of the defibrating agent, and the resulting chemically modified microfibrillated cellulose fibers are well dispersed in the vinyl chloride polymer (C) with the aggregation of the fibers suppressed.

[0107] In this kneading step, the defibrated raw material having a fiber diameter of several tens of micrometers to several hundreds of micrometers is defibrated into chemically modified microfibrillated cellulosic fibers having a fiber diameter of several tens of nanometers to several micrometers during kneading.

[0108] The defibrating raw material can be composited with the vinyl chloride polymer (C) while being defibrated by the shear stress of the melt kneader and the action of the defibrating agent during melt-kneading with the vinyl chloride polymer (C). Therefore, the melt-kneading method simplifies the production process and enables reduction in production costs.

[0109] Examples of the melt kneader include batch kneaders such as pressure kneaders and mixers; extrusion kneaders such as single-screw extruders, co-rotating twin-screw extruders, and counter-rotating twin-screw extruders; and calendar roll kneaders, and any combination of these may be used.

[0110] It is also possible to mix the defibrating raw material and the vinyl chloride polymer (C) in advance before melt-kneading them. For example, (i) a dry defibrating raw material can be mixed with a powdered or granular vinyl chloride polymer (C) and the resulting mixture can be supplied to a kneader. Alternatively, (ii) the defibrating raw material and the powdered or granular vinyl chloride polymer (C) can be dispersed in a dispersion liquid in which they are insoluble, mixed, and then dried and supplied to a kneader. As a mixing means, it is preferable to use a bench roll, a Banbury mixer, a kneader, a planetary mixer, a Henschel mixer, a mixer with stirring blades, or a revolution or rotation type mixer.

[0111] As in (i) above, when the dry defibrating raw material and the powdery or granular vinyl chloride polymer (C) are mixed in advance before melt-kneading, it is also possible to add additives during this mixing.

[0112] The content of the chemically modified microfibrillated cellulose fiber (chemically modified MFC) (A) in the vinyl chloride polymer composition (melt-kneaded composition) produced by the production method of the present invention is usually about 1 to 40 mass%, preferably 3 to 30 mass%, based on the total mass of the vinyl chloride polymer (C) and the chemically modified MFC (A). The content of the vinyl chloride polymer (C) in the melt-kneaded composition is usually about 60 to 99 mass%, preferably 70 to 97 mass%, based on the total mass of the resin (C) and the chemically modified MFC (A). By setting the content of the chemically modified MFC within the above range, a vinyl chloride polymer composition with excellent strength properties and heat resistance can be obtained.

[0113] The vinyl chloride polymer composition produced by the production method of the present invention can also be used as a masterbatch. When used as a masterbatch, the content of the chemically modified MFC (A) is preferably about 10 to 40 mass% based on the total mass of the vinyl chloride polymer (C) and the chemically modified MFC (A).

[0114] The vinyl chloride polymer composition of the present invention may contain additives to the extent that the effects of the present invention are not impaired. Examples of additives include compatibilizers, surfactants, starches, polysaccharides such as alginic acid, natural proteins such as gelatin, glue and casein, tannins, zeolites, ceramics, metal powders, inorganic compounds such as calcium carbonate, talc and mica, colorants, plasticizers, flame retardants, processing aids, impact modifiers, pigments, heat stabilizers, antistatic agents, ultraviolet absorbers and antioxidants.

[0115] 12. Molded body The vinyl chloride polymer composition of the present invention can be used to produce the molded article of the present invention. When producing the molded article, the vinyl chloride polymer composition can be processed into various shapes, such as pellets, powder, sheet, plate, or film, and used as a molding material.

[0116] Examples of molding methods include injection molding, mold molding, and extrusion molding. Examples of the shape of the molded product include sheet, plate, film, and three-dimensional structure. Molded products of various shapes depending on the application can be produced by the above molding methods. By using the vinyl chloride polymer composition of the present invention, molded products excellent in strength properties, heat resistance, and the like can be obtained.

[0117] Molded articles produced from the vinyl chloride polymer composition of the present invention can be used in fields requiring mechanical strength (such as tensile strength). Specific examples include building materials such as window frames, gutters, water and sewer pipes, joints, drainage basins, and siding; interior, exterior, and structural materials for transportation equipment such as automobiles, trains, ships, and airplanes; housings, structural materials, and internal parts for electrical appliances such as personal computers, televisions, telephones, and watches; housings, structural materials, and internal parts for mobile communication devices such as mobile phones; housings, structural materials, and internal parts for portable music players, video players, printers, copiers, sporting goods, and other office equipment; and containers and vessels for stationery and other office equipment. Among these, window frame materials are particularly effective and preferred. [Example]

[0118] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0119] The meanings of the abbreviations used in the examples and comparative examples are as follows: Ac: acetyl group TUKP: Unbleached kraft pulp from Todomatsu AcTUKP: A TUKP in which some of the hydrogen atoms of hydroxyl groups in the TUKP have been replaced with acetyl groups. TPG: Tripropylene glycol

[0120] Furthermore, the following terms used in the examples, comparative examples, figures, and tables have the following meanings. Pass: The number of times the material to be processed (test material) is supplied to the twin-screw kneader and passed through the kneader is called a "pass." For example, "1 pass" means that the material is passed through the kneader once, "1st pass" means that the test material is passed through the kneader for the first time (first time), and "2nd pass" means that the material that has been passed through the kneader once is then passed through the kneader for the second time. · Extrusion: This means feeding the material to be processed (test material) into a kneading machine (also called an extruder) and kneading it.

[0121] (A) Raw materials used In the following Production Examples, Examples and Comparative Examples, the following raw materials were used. (1) Resin Vinyl chloride homopolymer (hereinafter referred to as "PVC"): Taiyo PVC, TH-1000, powder ·workman Vinyl chloride in ethylene vinyl acetate copolymer Ru Graft-polymerized vinyl chloride copolymer (hereinafter also referred to as "EVA-G-PVC"): Taiyo PVC, powder Amount of ethylene vinyl acetate copolymer in EVA-G-PVC: 13% by mass Amount of vinyl chloride in EVA-G-PVC: 87% by mass Ethylene vinyl acetate copolymer; vinyl acetate (saponification degree: 0) content 26% by mass (2) Fiber ·AcTUKP:DS=0.86, crystallinity 81.3% (3) Defibrating agent ·TPG: isomer mixture (4) Additives Ca-Zn composite stabilizer (hereinafter simply referred to as "stabilizer") (5) Resin compound EVA-G-PVC compound: A compound blending 100 parts of EVA-G-PVC with 5 parts of stabilizer. PVC compound: A compound blending 100 parts by weight of PVC with 5 parts by weight of stabilizer.

[0122] (B) Equipment used Twin-screw kneader: Technobel, screw diameter φ15 mm, L / D=45 (L / D is the ratio of screw length (L) to screw diameter (D)) Roller: Kansai Roll, 8-inch hot water roll Compression molding machine: 50 ton automatic compression molding machine manufactured by Shinto Metal Industries.

[0123] (C) Method for producing a molded body The vinyl chloride polymer composition of the present invention was kneaded for 3 minutes using a roller set at a temperature of 185°C to prepare a roll-kneaded sheet. The obtained roll-kneaded sheet was press-molded for 20 minutes under conditions of a temperature of 185°C and a pressure of 15 MPa to prepare a molded product.

[0124] (D) Test Method (1) Microscopic observation of cellulosic fibers (hereinafter simply referred to as "fibers") The state of the fibers, or the defibrated or dispersed state of the fibers in the composition, was observed using an electron microscope as follows.

[0125] (1-1) Observation of the defibration state of fibers in a fiber-reinforced resin composition using a scanning electron microscope (a) Preparation of specimen for observation For the roll-kneaded sheet prepared by the method (C) above, the resin component (vinyl chloride polymer) was extracted and removed from the vinyl chloride polymer composition using tetrahydrofuran as an extraction solvent for the resin component, to prepare a sample. Specifically, the vinyl chloride polymer composition was placed in the extraction solvent and heated at 40 to 50°C, and the resin component was extracted and removed, obtaining an extraction residue mainly composed of fibers. This was removed as a sample piece, dried, and then osmium-coated using a sputtering device, and used as a sample for observation. (b) Observation The observation sample obtained in (a) above was subjected to secondary electron image observation using a field emission scanning electron microscope (JSM-7100F, manufactured by JEOL Ltd.).

[0126] (2) Tensile test method Measurements were carried out in accordance with JIS-K7161.

[0127] (3) Bending test method Measurements were carried out in accordance with JIS-K7171.

[0128] (4) Thermal conductivity measurement method Measurements were carried out in accordance with JIS-R1611.

[0129] (5) Vicat softening temperature measurement method Old JISK6760 1981 Measurements were carried out in accordance with the

[0130] (6) Measurement method of linear expansion coefficient Measurements were performed in the scanning range of 0 to 90°C, and the slope was calculated from 0 to 60°C.

[0131] Example 1 Manufacture of vinyl chloride polymer composition (composition ratio: AcTUKP / EVA-G-PVC compound / PVC compound = ((2.61 + 10) / 12.39 / 75)) The raw materials were mixed in a composition ratio of AcTUKP / EVA-G-PVC compound / TPG / water = (2.61+10) / 12.39 / 15 / 10 to prepare a mixture. Using this as the starting material, the title vinyl chloride polymer composition was produced according to the following steps (1st pass to 3rd pass). Composition ratio notation: The composition ratio of the above mixture fed into the twin-screw mixer is: AcTUKP / EVA-G-PVC compound / TPG / water = The numbers in (2.61+10) / 12.39 / 15 / 10 have the following meanings: (2.61 + 10): This represents the mass proportion of AcTUKP in the total mass of the mixture. Here, the 2.61 in (2.61 + 10) above refers to the mass proportion of the combined acetyl group (Ac) of AcTUKP (calculated from the DS value of AcTUKP) and lignin in the total mass of the mixture. Additionally, the 10 in (2.61 + 10) above refers to the mass proportion of the fiber components (i.e., cellulose + hemicellulose) in the total mass of the mixture. Therefore, (2.61 + 10) = 12.61 is the mass proportion of AcTUKP in the total mass of the mixture. 12.39: Mass proportion of EVA-G-PVC compound in the total mass of the mixture 15: Mass ratio of TPG in the total mass of the mixture 10: Mass ratio of water in the total mass of the mixture Unless otherwise specified, the composition ratios of mixtures and kneaded products will be described in accordance with this notation method. Furthermore, when the contents of water and defibrating agent (B1) in the melt-kneaded product and molded body (test piece) are very small, the composition ratios of water and defibrating agent (B1) are omitted from the composition ratio of the melt-kneaded product.

[0132] The manufacturing method will be described in detail below. (1st pass: dewatering extrusion) The starting material was subjected to dehydration extrusion by passing it through a twin-screw kneader equipped with a vent, with the kneader cylinder heated at a gradient temperature from 80°C (upstream) to 130°C (downstream). Water was expelled from the starting material, and the mixture was kneaded and discharged in an integrated state.

[0133] (2nd pass: melt kneading) The kneaded material after one pass was passed through a twin-screw kneader with the kneader cylinder set at 80°C and kneaded and extruded. Water and TPG were discharged from the kneaded material after one pass. The composition ratio of the kneaded material after two passes was AcTUKP / EVA-G-PVC compound / (TPG+water) = (2.61+10) / 12.39 / 14.85 (total parts by mass of the composition: 39.85).

[0134] (3rd pass: Dilution extrusion with PVC compound) The two-pass kneaded mixture was mixed with a PVC compound to obtain a mixture with a composition ratio of (two-pass mixture) / PVC compound = 39.85 / 75, which was melt-kneaded in a twin-screw kneader at a cylinder temperature of 175°C. During the melt-kneading process, degassing was performed using a vent installed in the twin-screw kneader to reduce the water and TPG in the mixture to an extent that would not significantly affect the strength properties of the vinyl chloride polymer composition produced, thereby obtaining the vinyl chloride polymer composition (melt-kneaded mixture) of Example 1, which contained 3 mass% or less of TPG as the defibrating agent (B1). The composition ratio of the resulting melt-kneaded mixture was AcTUKP / EVA-G-PVC compound / PVC compound = (2.61 + 10) / 12.39 / 75. As described above, the melt-kneaded product contains a small amount of TPG, which is the defibrating agent (B1), but because the compositional ratio is small, the compositional ratios of water and TPG, which is the defibrating agent (B1), are omitted in the notation of the compositional ratio.) This also applies to the vinyl chloride polymer compositions (melt-kneaded products) of Examples 2 to 4 below. The content of the defibrating agent (B1) in the vinyl chloride polymer compositions of Examples 2 to 4 was also 3 mass% or less. Amount of microfibrillated hydrophobic cellulose fiber (A): 12.61 parts by mass Amount of vinyl chloride polymer (C): 81.695 parts by mass The content (mass%) of the microfibrillated hydrophobic cellulose fibers (A) relative to the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C): 13.37 mass% The content of the vinyl chloride polymer (C) relative to the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C): 86.63% by mass Amount of hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms: 12.61 parts by mass Amount of defibrating agent (B1) used: 15 parts by weight Amount of vinyl chloride polymer (C) used: 81.695 parts by mass Amount of ethylene vinyl acetate copolymer (D): 1.534 parts by mass Amount of defibrating agent (B1) used per part by mass of hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms: 1.19 parts by mass Amount of vinyl chloride polymer (C) used per part by mass of hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms: 6.48 parts by mass The amount of ethylene-vinyl acetate copolymer (D) used per part by mass of the hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms: 0.12 parts by mass Test pieces (molded articles) were prepared from the resulting compositions according to the above conditions, and the test pieces were subjected to various tests according to the above methods. The results are shown in Table 1.

[0135] Example 2 A mixture was prepared by mixing AcTUKP / EVA-G-PVC compound / TPG / water in a composition ratio of (2.61+10) / 12.39 / 5 / 10, and this mixture was used as the starting material. A vinyl chloride polymer composition (melt-kneaded product) of Example 2 was obtained in the same manner as in Example 1, except that the cylinder temperature in the second pass was set to 95°C. Amount of microfibrillated hydrophobic cellulose fiber (A): 12.61 parts by mass Amount of vinyl chloride polymer (C): 81.695 parts by mass The content (mass%) of the microfibrillated hydrophobic cellulose fibers (A) relative to the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C): 13.37 mass% The content of the vinyl chloride polymer (C) relative to the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C): 86.63% by mass Amount of hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms: 12.61 parts by mass Amount of defibrating agent (B1) used: 5 parts by weight Amount of vinyl chloride polymer (C) used: 81.695 parts by mass Amount of ethylene vinyl acetate copolymer (D): 1.534 parts by mass Amount of defibrating agent (B1) used per part by mass of hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms: 0.40 parts by mass Amount of vinyl chloride polymer (C) used per part by mass of hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms: 6.48 parts by mass The amount of ethylene-vinyl acetate copolymer (D) used per part by mass of the hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms: 0.12 parts by mass Test pieces (molded articles) were prepared from the obtained compositions according to the above conditions, and the test pieces were subjected to various tests in the same manner as in Example 1. The results are shown in Table 1.

[0136] Example 3 A mixture was prepared by mixing AcTUKP / EVA-G-PVC compound / TPG / water in a composition ratio of (2.61+10) / 12.39 / 10 / 10, and this mixture was used as a starting material. The vinyl chloride polymer composition (melt-kneaded product) of Example 3 was obtained in the same manner as in Example 1, except that the resulting composition was washed with warm water at 80°C for 2 hours to remove the TPG. Amount of microfibrillated hydrophobic cellulose fiber (A): 12.61 parts by mass Amount of vinyl chloride polymer (C): 81.695 parts by mass The content (mass%) of the microfibrillated hydrophobic cellulose fibers (A) relative to the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C): 13.37 mass% The content of the vinyl chloride polymer (C) relative to the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C): 86.63% by mass Amount of hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms: 12.61 parts by mass Amount of defibrating agent (B1) used: 10 parts by weight Amount of vinyl chloride polymer (C) used: 81.695 parts by mass Amount of ethylene vinyl acetate copolymer (D): 1.534 parts by mass Amount of defibrating agent (B1) used per part by mass of hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms: 0.79 parts by mass Amount of vinyl chloride polymer (C) used per part by mass of hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms: 6.48 parts by mass The amount of ethylene-vinyl acetate copolymer (D) used per part by mass of the hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms: 0.12 parts by mass Test pieces (molded articles) were prepared from the obtained compositions according to the above conditions, and the test pieces were subjected to various tests in the same manner as in Example 1. The results are shown in Table 1.

[0137] Example 4 A mixture was prepared by mixing AcTUKP / EVA-G-PVC compound / TPG in a composition ratio of (2.61+10) / 12.39 / 10, and this mixture was used as a starting material. A vinyl chloride polymer composition of Example 4 was obtained in the same manner as in Example 1, except that the first pass (dehydration extrusion) was not performed and the cylinder temperature in the second pass was set to 90°C. Amount of microfibrillated hydrophobic cellulose fiber (A): 12.61 parts by mass Amount of vinyl chloride polymer (C): 81.695 parts by mass The content (mass%) of the microfibrillated hydrophobic cellulose fibers (A) relative to the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C): 13.37 mass% The content of the vinyl chloride polymer (C) relative to the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C): 86.63% by mass Amount of hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms: 12.61 parts by mass Amount of defibrating agent (B1) used: 10 parts by weight Amount of vinyl chloride polymer (C) used: 81.695 parts by mass Amount of ethylene vinyl acetate copolymer (D): 1.534 parts by mass Amount of defibrating agent (B1) used per part by mass of hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms: 0.79 parts by mass Amount of vinyl chloride polymer (C) used per part by mass of hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms: 6.48 parts by mass The amount of ethylene-vinyl acetate copolymer (D) used per part by mass of the hydrophobic cellulose fiber assembly (AP) modified with an acyl group having 2 to 5 carbon atoms: 0.12 parts by mass Test pieces (molded articles) were prepared from the obtained compositions according to the above conditions, and the test pieces were subjected to various tests in the same manner as in Example 1. The results are shown in Table 1.

[0138] (Comparative Example 1) Of the raw materials used in Example 1, only the PVC compound was melt-extruded (cylinder temperature 175°C) in a twin-screw kneader to obtain a vinyl chloride polymer composition (melt-kneaded product) of Comparative Example 1. Test pieces (molded articles) were prepared from the obtained composition according to the above-mentioned conditions, and the test pieces were subjected to various tests using the above-mentioned methods. The results are shown in Table 1.

[0139] (Comparative Example 2) Of the raw materials used in Example 1, an EVA-G-PVC compound / PVC compound was mixed in a composition ratio of EVA-G-PVC compound / PVC compound = 12.39 / 75, and the mixture was melt-extruded (cylinder temperature 175°C) in a twin-screw kneader to obtain a vinyl chloride polymer composition (melt-kneaded product) of Comparative Example 2. Test pieces (molded articles) were prepared from the resulting compositions according to the above conditions, and the test pieces were subjected to various tests according to the above methods. The results are shown in Table 1.

[0140] (Comparative Example 3) Among the raw materials used in Example 1, AcTUKP / EVA-G- A mixture was prepared by mixing the PVC compound and the AcTUKP in a composition ratio of AcTUKP / PVC compound = (2.61 + 10) / 12.39, and this mixture was used as a starting material. A vinyl chloride polymer composition (melt-kneaded product) of Comparative Example 3 was obtained in the same manner as in Example 1, except that the first pass (dehydration extrusion) was not performed and the cylinder temperature in the second pass was set to 175°C. Test pieces (molded articles) were prepared from the obtained compositions according to the above conditions, and the test pieces were subjected to various tests in the same manner as in Example 1. The results are shown in Table 1.

[0141] [Table 1]

[0142] Table 1 shows that all of the molded articles produced from the vinyl chloride polymer compositions of Examples 1 to 4 using the defibrating agent (B1) had improved tensile modulus, flexural strength, flexural modulus, and Vicat softening temperature, reduced linear expansion coefficient, and maintained thermal conductivity, compared to the molded article produced from the vinyl chloride polymer composition of Comparative Example 1 consisting only of PVC and the molded articles produced from the vinyl chloride polymer compositions of Comparative Examples 2 and 3 not using the defibrating agent (B1).

[0143] A sample for microscopic observation was prepared from the vinyl chloride polymer composition of Example 1 according to the conditions described above, and the state of the fibers in the sample was observed using an electron microscope. The electron microscope image is shown in Figure 1. For comparison, an electron microscope image of AcTUKP, which was used as a raw material for preparing the composition of Example 1, is shown in Figure 2.

[0144] Comparing Figures 1 and 2, it can be seen that the fiber diameter of AcTUKP before melt-kneading was approximately 10 μm or more, but was defibrated to several tens of nanometers to 5 μm by kneading.

Claims

1. A vinyl chloride polymer composition comprising microfibrillated hydrophobized cellulose fibers (A), a defibrating agent (B1), and a vinyl chloride polymer (C), the microfibrillated hydrophobic cellulosic fibers (A) are modified with an acyl group having 2 to 5 carbon atoms, and the defibrating agent (B1) is at least one compound selected from the group consisting of dipropylene glycol, triethylene glycol, diglycerol, tripropylene glycol, tetraethylene glycol, polyethylene glycol (number average molecular weight 200 to 400), polyoxypropylene glycol (number average molecular weight 200 to 400), and polyoxypropylene glyceryl ether (number average molecular weight 200 to 400); the content of the microfibrillated hydrophobic cellulose fibers (A) is 1 to 40% by mass based on the total mass of the microfibrillated hydrophobic cellulose fibers (A) and the vinyl chloride polymer (C), the content of the defibrating agent (B1) is 0.001% by mass or more and 5% by mass or less, based on the total mass of the vinyl chloride polymer composition; a content of the vinyl chloride polymer (C) in the vinyl chloride polymer composition is 60 to 99 mass% based on the total mass of the microfibrillated hydrophobized cellulose fibers (A) and the vinyl chloride polymer (C).

2. 2. The vinyl chloride polymer composition according to claim 1, further comprising an ethylene-vinyl acetate copolymer (D), wherein the ethylene-vinyl acetate copolymer (D) has a vinyl acetate content of 3% by mass or more and 85% by mass or less, and wherein acetyl groups of the vinyl acetate constituting the ethylene-vinyl acetate copolymer (D) have been substituted with hydrogen atoms by a saponification reaction, and the saponification degree is 0% or more and 95% or less.

3. 3. The vinyl chloride polymer composition according to claim 1, wherein all or a part of the vinyl chloride polymer (C) is a vinyl chloride copolymer (F) obtained by copolymerization of vinyl chloride and vinyl acetate, and the vinyl chloride copolymer (F) has a vinyl acetate content of 0.3 mass% or more and 30 mass% or less.

4. 3. The vinyl chloride polymer composition according to claim 1 or 2, further comprising a defibrating agent (B2) different from the defibrating agent (B1), wherein the defibrating agent (B2) is at least one selected from the group consisting of talc, clay, zeolite, aluminum oxide, calcium carbonate, titanium oxide, silica, magnesium oxide, and mica.

5. 3. The vinyl chloride polymer composition according to claim 1 or 2, wherein the microfibrillated hydrophobic cellulosic fibers (A) are modified with acetyl groups, and the defibrating agent (B1) is at least one selected from the group consisting of dipropylene glycol, tripropylene glycol, polyoxypropylene glycol (average molecular weight 200), and polyoxypropylene glyceryl ether (average molecular weight 250).

6. The vinyl chloride polymer composition according to any one of claims 1 to 5, wherein the microfibrillated hydrophobized cellulosic fibers (A) are microfibrillated hydrophobized lignocellulose fibers (MFLC).

7. A molded article comprising the vinyl chloride polymer composition according to any one of claims 1 to 6.

8. A window frame material comprising the vinyl chloride polymer composition according to any one of claims 1 to 6.

9. A hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms, a defibrating agent (B1), a vinyl chloride polymer (C), and optionally an ethylene-vinyl acetate copolymer (D), the amount of the defibrating agent (B1) used is 0.1 to 5 parts by mass per part by mass of the hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms, The amount of the vinyl chloride polymer (C) used is 3 to 100 parts by mass per part by mass of the hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms; and When an ethylene-vinyl acetate copolymer (D) is used as needed, the amount of the ethylene-vinyl acetate copolymer (D) used is set to 0.1 to 3 parts by mass per part by mass of the hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms, and mixing the hydrophobized cellulose fiber aggregate (AP) with the mixture, and defibrating and microfibrillating the hydrophobized cellulose fiber aggregate (AP) during the mixing operation.

1. A method for producing a vinyl chloride polymer composition containing microfibrillated hydrophobic cellulose fibers (A), a vinyl chloride polymer (C), and optionally an ethylene-vinyl acetate copolymer (D), comprising: the microfibrillated hydrophobic cellulosic fibers (A) are modified with an acyl group having 2 to 5 carbon atoms; The defibrating agent (B1) is at least one compound selected from the group consisting of dipropylene glycol, triethylene glycol, diglycerol, tripropylene glycol, tetraethylene glycol, polyethylene glycol (number average molecular weight 200 to 400), polyoxypropylene glycol (number average molecular weight 200 to 400), and polyoxypropylene glyceryl ether (number average molecular weight 200 to 400). A method for producing a vinyl chloride polymer composition.

10. 10. The method for producing a vinyl chloride polymer composition according to claim 9, wherein a defibrating agent (B2) different from the defibrating agent (B1) is further mixed in the step to produce a vinyl chloride polymer composition further containing a defibrating agent (B2), wherein the defibrating agent (B2) is at least one selected from the group consisting of talc, clay, zeolite, aluminum oxide, calcium carbonate, titanium oxide, silica, magnesium oxide, and mica.

11. (1) A hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms, a defibrating agent (B1), a vinyl chloride polymer (C), and optionally an ethylene-vinyl acetate copolymer (D), the amount of the defibrating agent (B1) used is 0.1 to 5 parts by mass per part by mass of the hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms, The amount of the vinyl chloride polymer (C) used is 3 to 100 parts by mass per part by mass of the hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms; and When an ethylene-vinyl acetate copolymer (D) is used as needed, the amount of the ethylene-vinyl acetate copolymer (D) used is set to 0.1 to 3 parts by mass per part by mass of the hydrophobic cellulose fiber aggregate (AP) modified with an acyl group having 2 to 5 carbon atoms, a first step of mixing the hydrophobic cellulosic fiber aggregate (AP) and defibrating and microfibrillating the hydrophobic cellulosic fiber aggregate (AP) during the mixing operation; (2) A second step of removing the defibrating agent (B1) from the mixture obtained in the first step, which contains the microfibrillated hydrophobic cellulose fibers (A), the defibrating agent (B1), the vinyl chloride polymer (C), and, if necessary, the ethylene-vinyl acetate copolymer (D), A method for producing a vinyl chloride polymer composition, comprising the steps of: modifying the microfibrillated hydrophobic cellulose fibers (A) with an acyl group having 2 to 5 carbon atoms; The defibrating agent (B1) is at least one compound selected from the group consisting of dipropylene glycol, triethylene glycol, diglycerol, tripropylene glycol, tetraethylene glycol, polyethylene glycol (number average molecular weight 200 to 400), polyoxypropylene glycol (number average molecular weight 200 to 400), and polyoxypropylene glyceryl ether (number average molecular weight 200 to 400). A method for producing a vinyl chloride polymer composition.

12. 12. The method for producing a vinyl chloride polymer composition according to claim 11, wherein a defibrating agent (B2) different from the defibrating agent (B1) is further mixed in the first step to produce a vinyl chloride polymer composition further containing a defibrating agent (B2), wherein the defibrating agent (B2) is at least one selected from the group consisting of talc, clay, zeolite, aluminum oxide, calcium carbonate, titanium oxide, silica, magnesium oxide, and mica.

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