JPH10182911A - Vinyl chloride-based resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vinyl chloride-based resin composition capable of providing a molding product having uniform and fine foamed cell structure and smooth epidermis, high mechanical strength, rich in woody feeling and suitable for building materials and materials for furniture. SOLUTION: This resin composition is obtained by compounding 100 pts.wt. vinyl chloride-based resin with 7-30 pts.wt. methyl methacrylate-based copolymer containing >=60wt.% methyl methacrylate unit and having 50-90 deg.C glass transition point of the copolymer and 1.5-4.0 specific viscosity, 0.1-3.0 pts.wt. heat decomposition type foaming agent and 5-150 pts.wt. wood powder having 50-500μm average particle diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride resin composition containing wood flour, and more particularly to a building material and a furniture material having a uniform and fine foamed cell structure and a smooth skin, and being rich in a wooden texture. The present invention relates to a vinyl chloride-based resin composition capable of providing a molded article suitable for a resin.

[0002]

2. Description of the Related Art Wood can be repeatedly produced by photosynthesis, and is therefore being reviewed as a promising resource that is different from petroleum-based resins. Attempts are being made to grow forests with fast-growing species and reduce the concentration of carbon dioxide in the atmosphere to restore a healthy global environment, while at the same time planning to cut down and use wood as a resource for human life. It is taking place.
Under these circumstances, we developed a vinyl chloride resin composition that is frequently used in building materials by blending wood flour with vinyl chloride resin, a general-purpose resin that has high mechanical strength and is easy to mold. If possible, a harmonious way to use earth resources will be greatly pioneered. 2. Description of the Related Art Conventionally, it is often practiced to mix wood powder with a vinyl chloride resin to form a wood-like appearance and tactile sensation. However, a vinyl chloride resin composition containing a considerable amount of wood flour has a problem that the mechanical strength such as tensile strength is significantly reduced, and a natural woody feeling has not yet been realized.

In order to improve the clarity and ease of processing of wood grain, a vinyl chloride resin composition to which wood powder is added in addition to a urea resin has been proposed (JP-A-60-42007, JP-A-60-73807, JP-A-60-73
808). In addition, an inorganic filler such as mica in addition to wood flour, polyethylene, ethylene-vinyl acetate copolymer or a vinyl chloride resin composition to which an ABS resin is added,
It has been disclosed that the coefficient of linear expansion is small and the impact resistance and moldability are excellent (JP-A-60-192746 and JP-A-60-192747). However, these also lack the uniform mixing property of wood flour and the appearance of the woody texture of the molded product is insufficient. Dispersion uniformity was greatly improved by blending wood powder to which inorganic powder or plastic powder was attached during plastic processing (Japanese Patent Laid-Open No. 5-177).
No. 610, JP-A-5-261708), a resin molded product rich in woody feeling has not yet been obtained simply by blending such a wood powder with a vinyl chloride resin.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention provides a window having a uniform and fine foam cell structure and a smooth skin, and having a low mechanical strength, a rich woody feeling, and a window. It is an object of the present invention to provide a vinyl chloride resin composition capable of providing a molded product reaching a building material such as a frame or a furniture material.

[0005]

Means for Solving the Problems The present inventors have solved the above problems by adding a methyl methacrylate copolymer having a specific glass transition point as a processing aid to a vinyl chloride resin. The present inventors have found that the above object can be achieved by blending wood powder and performing foam molding, and have completed the present invention based on this finding. That is, the present invention
(A) 100 parts by weight of a vinyl chloride resin, (B) 60% by weight or more of a methyl methacrylate unit, the copolymer has a glass transition point of 50 to 90 ° C. and a specific viscosity of 1.5 to 90 ° C.
4.0-methyl methacrylate copolymer 7-30
Parts by weight, (C) 0.1 to 3.0 parts by weight of a pyrolytic foaming agent,
And (D) wood flour 5 to 15 having an average particle size of 50 to 500 μm.
The present invention provides a vinyl chloride resin composition containing 0 parts by weight.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The vinyl chloride resin used as the component (A) in the composition of the present invention is a homopolymer of vinyl chloride or a copolymer containing 50% by weight or more of vinyl chloride as a main component. Examples of the comonomer in the case of the vinyl chloride copolymer include olefins such as ethylene and propylene; allyl chloride, vinylidene chloride, vinyl fluoride,
Halogenated olefins such as ethylene trifluoride chloride;
Carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as isobutyl vinyl ether and cetyl vinyl ether; allyl ethers such as allyl-3-chloro-2-oxypropyl ether and allyl glycidyl ether; acrylic acid and maleic acid , Itaconic acid, 2-hydroxyethyl acrylate,
Unsaturated carboxylic acids such as methyl methacrylate, monomethyl maleate, diethyl maleate and maleic anhydride, esters or acid anhydrides thereof; unsaturated nitriles such as acrylonitrile and methacrylonitrile; acrylamide, N-methylolacrylamide, acrylamide Acrylamides such as -2-methylpropanesulfonic acid and (meth) acrylamidopropyltrimethylammonium chloride; allylamine such as allylamine benzoate and diallyldimethylammonium chloride; and derivatives thereof. The monomers exemplified above are only a part of copolymerizable monomers, and are exemplified in “Polyvinyl Chloride” edited by Kinki Chemical Association Vinyl Subcommittee, Nikkan Kogyo Shimbun (1988), pp. 75-104. Various monomers can be used. Ethylene-
Graft polymerization of vinyl chloride or vinyl chloride and the copolymerizable monomer to a resin such as vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, or chlorinated polyethylene. Such resins are also included. These vinyl chloride resins are
It may be produced by any conventionally known production method such as suspension polymerization, emulsion polymerization, solution polymerization and bulk polymerization. The average degree of polymerization is preferably from 400 to 1500, more preferably from 600 to 1500, as measured according to JIS K 6721.
Those in the range of 1100 can be suitably used. If the average degree of polymerization of the vinyl chloride resin is less than 400, the expansion ratio tends to be difficult to increase, and
If it is larger, many coarse cells may be mixed in the foam cells.

In the present invention, the copolymer (B) contains methyl methacrylate units in an amount of 60% by weight or more, the copolymer has a glass transition point of 50 to 90 ° C. and a specific viscosity of 1.5.
A methyl methacrylate copolymer having a molecular weight of from 4.0 to 4.0 is used. Since the glass transition point of the methyl methacrylate homopolymer is 105 ° C., in order to obtain the copolymer of the component (B), the homopolymer having a sufficiently low glass transition point as a comonomer of methyl methacrylate is required. Needs to be selected. Such monomers include:
Methyl acrylate (glass transition point of homopolymer 8
° C), ethyl acrylate (-22 ° C), n-propyl acrylate (-52 ° C), n-butyl acrylate (-54 ° C), isobutyl acrylate (-24 ° C)
° C), n-octyl acrylate (-65 ° C), 2-
Ethylhexyl acrylate (-85 ° C), n-lauryl acrylate (15 ° C), n-tetradecyl acrylate (20 ° C), methoxyethyl acrylate (-85 ° C), ethoxyethyl acrylate (-5 ° C)
Acrylates such as cyclohexyl acrylate (15 ° C.) and benzyl acrylate (6 ° C.); n
-Amyl methacrylate (10 ° C), n-octyl methacrylate (-20 ° C), n-decyl methacrylate (-65 ° C), n-lauryl methacrylate (-
Methacrylates such as n-cetyl methacrylate (15 ° C.) and dienes such as butadiene and isoprene; these may be used alone or may be used.
A combination of more than one species may be used. Particularly, n-butyl acrylate is preferred. The copolymer of the component (B) contains methyl methacrylate monomer unit in an amount of 60% by weight or more and has a glass transition point of 60 to 90 ° C., so that methyl methacrylate and the above comonomer can be used. May be contained as a third monomer unit. Examples of such a copolymerizable monomer include aromatic vinyl compounds such as styrene, vinyltoluene, and α-methylstyrene; unsaturated nitriles such as (meth) acrylonitrile and vinylidene cyanide; Rate, hydroxybutyl vinyl ether, monobutyl maleate, glycidyl methacrylate, butoxyethyl methacrylate and the like.

The particle structure of the methyl methacrylate copolymer of the component (B) may be a polymer composition obtained by a one-stage polymerization reaction and having a substantially uniform polymer composition inside the particles, or a so-called core-shell structure or the like. The polymer composition may be different for each fault. When the particle structure of the methyl methacrylate copolymer (B) is a core-shell particle, the weight ratio of the core to the shell is preferably 1/1 to 15/1,
The difference between the glass transition points of the core and the shell is preferably 50 ° C. or less. The glass transition point of the methyl methacrylate copolymer of the component (B) needs to be 50 to 90 ° C, preferably 60 to 75 ° C. When the glass transition point of the component (B) is less than 50 ° C., the powders tend to stick to each other (blocking) during storage in a warehouse or the like in summer,
If the glass transition point of the component (B) is higher than 90 ° C., the molded article is liable to cause poor foaming. In the present invention, the glass transition point is measured by a differential thermal analyzer.

The methyl methacrylate copolymer used as the component (B) has a specific viscosity at 25 ° C. of 100 ml of a chloroform solution in which 0.2 gr is dissolved.
It is necessary to be 5 to 4.0, and it is preferable to be in the range of 2.0 to 3.0. When the specific viscosity is less than 1.5, the surface of the molded article becomes rough, and when it exceeds 4.0, time is required for uniform melting. For adjusting the specific viscosity, a general method such as selection of a polymerization reaction temperature and use of a chain transfer agent such as t-dodecyl mercaptan and carbon tetrachloride can be adopted. The methyl methacrylate copolymer of the component (B) is
It has the effect of improving the melt viscosity characteristics of the vinyl chloride resin, dispersing the wood powder evenly in the vinyl chloride resin, maintaining the film strength of the foam cell, and making it less susceptible to breakage. The compounding amount of the component (B) in the present invention is required to be 7 to 30 parts by weight, preferably 10 to 20 parts by weight, per 100 parts by weight of the vinyl chloride resin of the component (A). (B) The amount of the component is 7
When the amount is less than the weight part, the holding strength of the film strength at the time of foaming becomes weak, and the foam cells are easily broken. On the other hand, if the amount exceeds 30 parts by weight, the melt viscosity increases, the heat generation increases, and the resin tends to be thermally degraded, and the size of the foam cells tends to be uneven.

As the thermal decomposition type foaming agent which is the component (C) of the composition of the present invention, a thermal decomposition type organic foaming agent and / or a thermal decomposition type inorganic foaming agent are used. Examples of the former are N,
N'-dinitrosopentamethylenetetramine, N, N '
Nitroso compounds such as -dimethyl-N, N'-dinitrosoterephthalamide; azo compounds such as azodicarbonamide and azobisisobutyronitrile; benzenesulfonylhydrazide, p, p'-oxybis (benzenesulfonylhydrazide), toluenesulfonylhydrazide And the like. Examples of the latter include sodium bicarbonate, ammonium bicarbonate, ammonium carbonate and the like. In the present invention, one or more kinds selected from the group of the organic or / and inorganic pyrolytic foaming agents described above can be used. In the present invention, it is inappropriate to heat and volatilize low-boiling organic compounds such as trifluoromethane and petroleum ether for use as a blowing agent. This is because the foam cells become coarse, and it becomes difficult for the molded product to be nailed or screwed, and may not be suitable for building materials. In the present invention, the compounding amount of the thermal decomposition type foaming agent of the component (C) is 100 parts of the vinyl chloride resin of the component (A).
0.1 to 3.0 parts by weight per part by weight is required, and preferably 0.5 to 1.5 parts by weight. If the amount of the component (C) is less than 0.1 part by weight, the molded article obtained with a low expansion ratio tends to lack woody feel, and conversely 3.0.
If the amount is more than the weight part, the surface of the molded article tends to be rough and the surface hardness tends to decrease.

In the present invention, as the component (D), wood powder having an average particle size of 50 to 500 μm is contained in an amount of 5 to 150 parts by weight, preferably 22 to 120 parts by weight, per 100 parts by weight of the vinyl chloride resin (A). More preferably, 25 to 100 parts by weight are used. If the amount of the wood flour is less than 5 parts by weight, it is difficult for the molded article to exhibit a woody feeling, and if it exceeds 150 parts by weight, the molded article becomes brittle. In the present invention, by mixing the component (B), wood flour can be reduced to 20%.
Even if blended in a high number of parts exceeding the weight part, it has good familiarity with the vinyl chloride resin and can be dispersed uniformly, so it has a uniform fine foam cell and a smooth skin by foam molding, and also has a strong wooden texture It can be expressed. The tree species of the wood flour used in the present invention is not particularly limited, and coniferous or hardwood timber pieces such as cedar, hemlock and lauan, and wood such as planing and sawdust can be used. In order to obtain the component (D) of the present invention from such wood, for example, the wood is preferably made into a relatively round wood powder having an average particle diameter of 500 μm or less by a pulverizer. The wood flour used in the present invention may be one obtained by adhering hard small particles to the surface as disclosed in JP-A-5-177610 and JP-A-5-261708. The mode in which the hard small particles adhere to the wood flour surface is hard, such as an entanglement bond including biting of the hard small particles into the wood flour, a narrowing bond between a plurality of bite-bonded hard small particles, and the like. Small particles may be adhered to the surface of wood flour by an external force, or hard small particles may be adhered to wood flour using an adhesive. In this case, the wood flour is replaced with hard small particles 1
It is charged in a ball mill or the like together with about 50% by weight, and is treated under a nitrogen atmosphere to prevent dust explosion.

The average particle size of the component (D) used in the present invention is 50 to 500 μm, preferably 30 to 100 μm. Here, the average particle diameter means a reading of the value of the mesh corresponding to 50% by weight of a curve obtained by analyzing the powder by sieve analysis to obtain a cumulative weight% curve with respect to the mesh. (D) The average particle size of the component is 50μ.
If it is less than m, the bulk specific gravity becomes small and the mixing operability for preparing the composition becomes poor, and if it is more than 500 μm, the molded article surface becomes rough and the foaming ratio decreases. The water content of the component (D) is preferably 10% by weight or less, more preferably 5% by weight or less. In the composition of the present invention,
In addition to the above components, in addition to heat stabilizers and lubricants used during the processing of ordinary vinyl chloride resin, ultraviolet absorbers,
An impact resistance enhancer, a pigment, a plasticizer, an antistatic agent and the like are appropriately added.

In order to prepare the composition of the present invention, first, components (A), (B) and (C) excluding the pyrolytic foaming agent of component (C) are mixed together in a Henschel mixer or the like. The temperature is increased to 120 to 160 ° C. with vigorous stirring and mixing. In this mixing process, the moisture absorbed in the wood flour is volatilized. When the above temperature is reached, the mixture is transferred to a cooling mixer, and the temperature is reduced to 50 to 60 ° C. after adding the pyrolytic foaming agent of the component (C). The removed powdery mixture can be used as a molding compound as it is, but is usually then pelletized. As a preferable method for producing pellets, a twin-screw extruder is used,
A method of producing pellets at a temperature of up to 170 ° C. and discharging residual moisture in wood flour through a vent hole. In the above method for preparing the composition of the present invention, the bulk components are large and the additives such as pigments are uniformly dispersed by adding and mixing all components except the foaming agent at the time of initial mixing with a Henschel mixer or the like. A mixture can be obtained. A molding method for obtaining a vinyl chloride resin molded product similar to natural wood using the composition of the present invention is not particularly limited, but usually an extrusion molding method is employed.

The embodiments of the present invention are described below. (1) (A) 100 parts by weight of a vinyl chloride resin, (B) 60% by weight or more of a methyl methacrylate unit, the copolymer has a glass transition point of 50 to 90 ° C, and a specific viscosity of 1.5 to 90 ° C. 7 to 30 parts by weight of a methyl methacrylate-based copolymer of 4.0, (C) 0.1 to 3.0 of a pyrolytic foaming agent
Parts by weight and (D) 5-150 parts by weight of wood flour having an average particle size of 50 to 500 μm. (2) The average degree of polymerization of the vinyl chloride resin is 400 to 150.
The vinyl chloride resin composition according to the above (1), wherein 0 is 0. (3) (A) 100 parts by weight of a vinyl chloride resin, (B) 60% by weight or more of a methyl methacrylate unit, and the copolymer has a glass transition point of 50 to 90 ° C. and a specific viscosity of 2.0 to 2.0. 7 to 30 parts by weight of a methyl methacrylate-based copolymer of 3.0, and (C) a thermal decomposition type foaming agent of 0.1 to 3.0.
Parts by weight and (D) 5-150 parts by weight of wood flour having an average particle size of 50 to 500 μm. (4) The average degree of polymerization of the vinyl chloride resin is 400 to 150.
The vinyl chloride resin composition according to the above (3), which is 0. (5) (A) 100 parts by weight of a vinyl chloride resin, (B) 60% by weight or more of a methyl methacrylate unit, and the copolymer has a glass transition point of 60 to 75 ° C and a specific viscosity of 1.5 to 1.5. 7 to 30 parts by weight of a methyl methacrylate-based copolymer of 4.0, (C) 0.1 to 3.0 of a pyrolytic foaming agent
Parts by weight and (D) 5-150 parts by weight of wood flour having an average particle size of 50 to 500 μm. (6) The average degree of polymerization of the vinyl chloride resin is 400 to 150.
The vinyl chloride resin composition according to the above (5), wherein 0 is 0. (7) (A) 100 parts by weight of a vinyl chloride resin, (B) 60% by weight or more of a methyl methacrylate unit, the copolymer has a glass transition point of 60 to 75 ° C, and a specific viscosity of 2.0 to 2.0. 7 to 30 parts by weight of a methyl methacrylate-based copolymer of 3.0, and (C) a thermal decomposition type foaming agent of 0.1 to 3.0.
Parts by weight and (D) 5-150 parts by weight of wood flour having an average particle size of 50 to 500 μm. (8) The average degree of polymerization of the vinyl chloride resin is 400 to 150.
The vinyl chloride resin composition according to the above (7), which is 0. (9) (A) 100 parts by weight of a vinyl chloride resin, (B) 60% by weight or more of a methyl methacrylate unit, the copolymer has a glass transition point of 50 to 90 ° C, and a specific viscosity of 1.5 to 90%. 7 to 30 parts by weight of a methyl methacrylate-based copolymer of 4.0, (C) 0.1 to 3.0 of a pyrolytic foaming agent
A vinyl chloride-based resin composition comprising, by weight, 22 to 120 parts by weight of wood powder (D) having an average particle size of 50 to 500 μm. (10) (A) 100 parts by weight of vinyl chloride resin, (B)
7-30 parts by weight of a methyl methacrylate-based copolymer containing 60% by weight or more of methyl methacrylate units, having a glass transition point of 50 to 90 ° C. and a specific viscosity of 2.0 to 3.0. (C) Pyrolytic foaming agent 0.1 to 3.0
A vinyl chloride-based resin composition comprising, by weight, 22 to 120 parts by weight of wood powder (D) having an average particle size of 50 to 500 μm. (11) (A) 100 parts by weight of vinyl chloride resin, (B)
7-30 parts by weight of a methyl methacrylate-based copolymer containing 60% by weight or more of methyl methacrylate units, having a glass transition point of 60 to 75 ° C. and a specific viscosity of 1.5 to 4.0. (C) Pyrolytic foaming agent 0.1 to 3.0
A vinyl chloride-based resin composition comprising, by weight, 22 to 120 parts by weight of wood powder (D) having an average particle size of 50 to 500 μm. (12) (A) 100 parts by weight of vinyl chloride resin, (B)
7-30 parts by weight of a methyl methacrylate-based copolymer containing 60% by weight or more of methyl methacrylate units, having a glass transition point of 60 to 75 ° C. and a specific viscosity of 2.0 to 3.0. (C) Pyrolytic foaming agent 0.1 to 3.0
Parts by weight and (D) 5-150 parts by weight of wood flour having an average particle size of 50 to 500 μm.

[0015]

EXAMPLES Next, the resin composition of the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, the number of parts and% are based on weight. Methyl methacrylate copolymers A to G were prepared as follows.

Preparation Example 1 of Methyl Methacrylate Copolymer 150 parts of water was put into a stainless steel reactor, degassed, and then 85 parts of methyl methacrylate and 15 parts of n-butyl acrylate were added.
Parts, 1 part of sodium alkyl sulfate having 12 to 18 carbon atoms and 0.1 part of potassium persulfate were added thereto, and emulsion polymerization was carried out at a polymerization temperature of 55 ° C. with stirring. After confirming the polymerization rate of 91%, the reaction was terminated to obtain a latex. The obtained latex was added to a 1% by weight aqueous solution of aluminum sulfate at 50 ° C. with stirring, and further heated to 90 ° C. for salting out, coagulating, dehydrating, washing, and drying to obtain a copolymer A. . Composition of copolymer A, differential thermal analyzer (SEIKO SSC / 520)
Table 1 shows the glass transition point, the specific viscosity, the solidification property, and the fixability measured by DSC 220). The evaluation of the coagulability was as follows. That is, 0.0 g of carbon was added to 50 g of the powder obtained by coagulation.
5 g was added, and the raw tap was subjected to sieve analysis for 30 minutes, and evaluated by the following three steps. ：: 50% by weight of 150 to 500 μm and 150 mesh passing amount <1% by weight Δ: 50% by weight of 150 to 500 μm and 150 mesh passing amount of 1 to 5% by weight ×: 50 The weight% passage diameter is 150 to 500 μm, and the 150 mesh passage amount is greater than 5% by weight. Fill the cylinder with a diameter of 77 mm and a length of 75 mm with the solidified powder by natural fall, remove the load on it over 1 minute, turn the container sideways and break the unity of powder within 1 minute. Observe if not. When the powder collapses, the load is sequentially increased, and the load at which the powder is fixed without collapsing is examined, and evaluated in the following three stages. ：: Does not stick even with a load of 1000 g. Δ: fixed with a load of 500 to 1000 g. X: It adheres with a load smaller than 500 g.

Preparation Example 2 of Methyl Methacrylate Copolymer The same procedure was carried out as in Preparation Example 1 of methyl methacrylate copolymer except that 80 parts of methyl methacrylate was used and 20 parts of ethyl acrylate was used instead of 15 parts of n-butyl acrylate. Copolymer B was obtained. Table 1 also shows the test results such as the composition of the copolymer B.

Production Example 3 of Methyl Methacrylate Copolymer 150 parts of water was put into a stainless steel container, degassed, and 0.8 parts of sodium alkyl sulfate having 12 to 18 carbon atoms was prepared.
0.8 part of lauryl alcohol, 0.2 part of lauroyl peroxide, 60 parts of methyl methacrylate, 30 parts of methyl acrylate and 10 parts of styrene are mixed, mixed at room temperature for 30 minutes, homogenized with a homogenizer, and transferred to a stainless steel reactor. did. The reactor temperature was raised to 55
The polymerization reaction was carried out at a temperature of ° C., and after confirming the polymerization rate of 90% by the solid content concentration of the reaction solution sampled in a small amount, the reaction was terminated to obtain a latex. After salting out, washing and drying in the same manner as in Production Example 1 of methyl methacrylate copolymer,
I got Table 1 shows the test results such as the composition of the resin C.

Preparation Example 4 of Methyl Methacrylate Copolymer The same procedure was carried out as in Preparation Example 1 of methyl methacrylate copolymer except that 90 parts of methyl methacrylate was used and 10 parts of ethyl acrylate was used instead of 15 parts of n-butyl acrylate. Copolymer D was obtained. Table 1 also shows the test results such as the composition of Copolymer D.

Production Example 5 of Methyl Methacrylate Copolymer In addition to 65 parts of methyl methacrylate, 35 parts of 2-ethylhexyl acrylate instead of 40 parts of methyl acrylate and styrene in total, and 0.1 part of t-dodecyl mercaptan were added. Was performed in the same manner as in Production Example 3 of a methyl methacrylate copolymer to obtain a copolymer E. Table 1 also shows the test results such as the composition of the copolymer E.

Preparation Example 6 of Methyl Methacrylate Copolymer The same procedure was carried out as in Preparation Example 1 of methyl methacrylate copolymer except that 40 parts of methyl methacrylate was used and 60 parts of methyl acrylate was used instead of 15 parts of n-butyl acrylate. Copolymer F was obtained. Table 1 also shows the test results such as the composition of the copolymer F.

Production Example 7 of Methyl Methacrylate Copolymer 70 parts of methyl methacrylate and 30 parts of ethyl acrylate instead of 15 parts of n-butyl acrylate
Except that 0.3 part of t-dodecyl mercaptan was added, the same procedure was performed as in Production Example 1 of methyl methacrylate copolymer,
Copolymer G was obtained. Table 1 also shows the test results such as the composition of the copolymer G.

Preparation Example 8 of Methyl Methacrylate Copolymer Preparation Example 1 of methyl methacrylate copolymer except that ethyl acrylate was used instead of n-butyl acrylate
Was carried out in the same manner as in the above to obtain a copolymer H. Table 1 also shows the test results such as the composition of the copolymer H.

The properties of the foam molded article were examined by the following methods. 1) Foam Cell State The cut surface of the molded product is observed with an optical microscope and evaluated according to the following rank. A: The cell is fine and uniform with a cell diameter of 100 μm or less. B: Some cells are broken and coarse. C: Many cells are broken and coarse. D: Most of the cells are broken and coarse. 2) Molded product surface properties The surface of the molded product is visually observed and touched, and evaluated according to the following rank. A: Smooth B: Slightly shark skin C: Shark skin D: Many granular projections. 3) True specific gravity and molded product specific gravity Measured by the underwater substitution method according to JIS K 7112. 4) Molding product expansion ratio Using the specific gravity value obtained by the above measurement, the expansion ratio is determined by the following equation. Expansion ratio = true specific gravity / specific gravity of molded product 5) Tensile strength Tensile speed of 10 mm with JIS K 7113 No. 1 test piece
/ Min.

Examples 1 to 4 and Comparative Examples 1 to 7 The components and types shown in Table 2 were blended in a Henschel mixer in the following manner. Water vapor was volatilized while charging and mixing a vinyl chloride resin, a methacrylic ester resin (except for Comparative Example 1), wood flour, a heat stabilizer, a lubricant, a filler, and a pigment. When the temperature rose to 140 ° C., the mixture was transferred to a cooling mixer and mixed, and after the temperature dropped to 60 ° C., the blowing agent was added. The obtained powdery mixture was formed into pellets under the following conditions using a single screw extruder having a cylinder diameter of 65 mm. In addition, the water remaining in the wood powder was volatilized from the vent hole. Screw: L / D = 24, compression ratio 2.5, rotation speed 30
rpm Set temperature: C ₁ = 130 ° C., C ₂ = 140 ° C., C ₃ =
150 ° C. C ₄ = 160 ° C., head 160 ° C., die 160 ° C. Dice: 3 mmφ pellet × 12 holes Land length: 10 mm The pellet thus obtained was extruded and foamed by a uniaxial extruder having a cylinder diameter of 40 mm under the following conditions. . Table 1 shows the characteristics of the molded product. Screw: L / D = 24, compression ratio 2.5, rotation speed 25
rpm Set temperature: C ₁ = 140 ° C., C ₂ = 160 ° C., C ₃ =
170 ° C. C ₄ = 180 ° C., head 160 ° C., D ₁ = 160 ° C. D ₂ = 160 ° C. Dice: thickness 4 mm width × 50 mm belt land length: 5 mm

[0026]

[Table 1]

Note MMA: methyl methacrylate MA: methyl acrylate EA: ethyl acrylate n-BA: n-butyl acrylate 2-EHA: 2-ethylhexyl acrylate ST: styrene

[0028]

[Table 2]

Note * 1 ZEST 700L, manufactured by Shin-Daiichi PVC Co., Ltd., vinyl chloride resin, average degree of polymerization 680 * 2 Wood powder with titanium oxide particles attached, manufactured by Misawa Techno Co., Ltd.
E60-T5-3, titanium oxide content 5% by weight, average particle size 60 μm, water content 5% * 3 Celluunt, manufactured by Shimada Shokai Co., Ltd., wood flour, average particle size 80 μm, moisture 5% by weight * 4 three bases Lead sulfate / lead stearate composite heat stabilizer * 5 Polyethylene wax * 6 Calcium carbonate CCR, Shiraishi calcium
* 7 Carbon black (TPH0012, manufactured by Toyo Ink Mfg. Co., Ltd.) / Condensed azo red (TXH4360,
Company pigment) / Bisazo Yellow (TXH2110, Company) composite pigment

In Examples 1 to 4 molded using the composition satisfying the requirements of the present invention, molded articles having good foaming cell state and surface properties and sufficient expansion ratio were obtained. However, in Comparative Example 1 using a copolymer D having a glass transition point of a methyl methacrylate copolymer exceeding 90 ° C., a foam having many broken cells and coarse cells and a slightly shark-skin-like surface was obtained. Conversely, in Comparative Examples 2 and 3 using copolymers E or F having a glass transition point of less than 50 ° C., the foam cell state was good, but the foam surface was slightly shark-skin-like and unsatisfactory. became. Comparative Example 4 using the copolymer G having a specific viscosity of the methyl methacrylate copolymer smaller than the specified value also gave a slightly shark-skin foam surface, and conversely, used the copolymer H having the specific viscosity larger than the specified value. In Comparative Example 5, both the cell state and the surface of the foam were slightly rough, and the expansion ratio was poor. In Comparative Example 6 in which the number of parts of the methyl methacrylate-based copolymer was smaller than the specified value and Comparative Example 7 in which the number of the methyl methacrylate-based copolymer was larger than the specified value, a foam having a cell state and a rough surface was obtained.

[0031]

EFFECTS OF THE INVENTION By using the composition of the present invention, it is possible to obtain a building material and a furniture material having a uniform and fine foamed cell structure and a smooth skin, and having a sufficient wooden strength and sufficient mechanical strength. Goods are obtained.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shinichi Akaya 1-2-1 Kawasaki-ku, Kawasaki-ku, Kawasaki, Kanagawa Prefecture Inside the ZEON Kasei Co., Ltd.Kawasaki Research Laboratories (72) Inventor Toshiya Kobayashi, Kanagawa No. 2 ZEON Kasei Co., Ltd. Kawasaki Laboratory

Claims (1)

[Claims] (A) 100 parts by weight of a vinyl chloride resin,
(B) Methyl methacrylate-based copolymers 7 to 30 containing 60% by weight or more of methyl methacrylate units, having a glass transition point of 50 to 90 ° C. and a specific viscosity of 1.5 to 4.0. Parts by weight, (C) pyrolytic foaming agent 0.1 to
3.0 parts by weight, and (D) average particle size of 50 to 500 μm
A vinyl chloride resin composition comprising 5-150 parts by weight of wood flour.