KR100487785B1 - Vinly chloride based resin composition containing wood meal and method for preparing the same - Google Patents

Abstract

100 parts by weight of (A) vinyl chloride resin, (B) 65 to 88% by weight of methacrylate, 35 to 12% by weight of (meth) acrylate having a glass transition point of the homopolymer of -20 ° C or less, and copolymerization with these if necessary. 5 to 30 parts by weight of a methacrylic acid ester resin having a specific viscosity of 1.5 to 4.0 and a monomer unit of 100 to 100% by weight in total of possible monomers of 0 to 10% by weight, (C) 0.1 to 3.0 parts by weight of a thermally decomposable blowing agent, and ( D) 5 to 150 parts by weight of wood powder having an average particle diameter of 50 to 500 µm is formulated, wherein the methacrylic acid ester resin is composed of particles having a core-cell structure, and the core layer is a homopolymer of methyl methacrylate. Or a copolymer containing 70% by weight or more of methyl methacrylate units and 30% by weight or less of (meth) acrylate units having a glass transition point of the homopolymer of -20 ° C or less, and the cell layer is a glass transition of the homopolymer. (Meta) arc with point below -20 ℃ The amount of (meth) acrylate units in the copolymer constituting the cell layer is higher than the amount of (meth) acrylate in the copolymer constituting the core layer. Provided is a vinyl chloride resin composition characterized by many. The molded article obtained in this composition has a uniform fine foam cell structure and a smooth skin, and has a high mechanical strength and a rich wood texture, making it suitable for building materials and furniture materials.

Description

VINLY CHLORIDE BASED RESIN COMPOSITION CONTAINING WOOD MEAL AND METHOD FOR PREPARING THE SAME

(Technology)

The present invention relates to a vinyl chloride resin composition comprising wood flour and a method for producing the same. This wood flour-containing vinyl chloride-based resin composition has a uniform fine foamed cell structure and a smooth skin, and is rich in wood feel and can provide molded articles suitable for building materials and furniture materials.

(Background)

Since wood can be repeatedly produced by photosynthesis, it is being reassessed as a resource with abundant prospects different from petroleum resins. Attempts are being made to use wood as a resource for human life as a resource for rapidly growing forests, reducing carbon dioxide concentrations in the atmosphere, and regenerating a healthy global environment. . Under such circumstances, harmonizing the length of harmonized use of earth resources if vinyl chloride resin, which is a general purpose resin with high mechanical strength and easy molding, can be mixed with wood powder to develop a vinyl chloride resin composition that is widely used in building materials. It will be greatly pioneered.

Conventionally, wood powder is blended and molded into vinyl chloride-based resins for the purpose of showing the appearance and feel similar to wood. However, since a significant amount of wood powder must be blended, there is a problem in that mechanical strength such as tensile strength is drastically lowered and natural wood is not yet realized.

In order to improve the clarity of wood grains and the ease of processing, vinyl chloride-based resin compositions containing urea resins other than wood flour have been proposed (Japanese Patent Application Laid-Open Nos. 60-42007, 60-73807, and 60-73808). report). In addition, it has been disclosed that vinyl chloride resin compositions containing inorganic fillers such as mica and polyethylene, ethylene-vinyl acetate copolymers or ABS resins in addition to wood flour have a low coefficient of linear expansion and excellent impact resistance and moldability. -192746, Japanese Patent Application Laid-Open No. 60-192747). However, these also lack the uniform mixing properties of the wood powder, and the appearance of wood texture of the molded article is insufficient.

The uniform dispersibility of wood powder is greatly improved by blending wood powder with inorganic powder or plastic powder in plastic processing (JP-A-5-177610, JP-A-5-261708) .By simply mixing wood powder with vinyl chloride resin The resin molded article rich in wood texture was not obtained only by doing it.

(Initiation of invention)

In view of the above situation, an object of the present invention is to provide a uniform foam cell structure and a smooth skin, and to maintain the good mechanical strength of the vinyl chloride-based resin molded article inherently, and to be rich in wood texture. It is to provide a vinyl chloride-based resin composition that can provide a molded article suitable for building materials or furniture.

Another object of the present invention is to provide an industrially advantageous method for producing such a vinyl chloride resin composition.

MEANS TO SOLVE THE PROBLEM The present inventors discovered that the said objective is achieved by mix | blending and shape | molding the vinyl chloride resin and the methacrylic acid ester type resin of a specific composition as processing aid together with wood powder, and based on this knowledge, this invention was discovered. Came to complete.

That is, in one aspect of the present invention, (A) 100 parts by weight of vinyl chloride resin, (B) 5 to 30 parts by weight of methacrylic acid ester resin, (C) 0.1 to 3.0 parts by weight of thermal decomposition foaming agent and (D A vinyl chloride resin composition comprising 5 to 150 parts by weight of wood powder having an average particle diameter of 50 to 500 µm, wherein the methacrylic acid ester resin is 65 to 88% by weight of methyl methacrylate and has a glass transition point of the homopolymer. Methacrylic having a specific viscosity of 1.5 to 4.0, consisting of 35 to 12% by weight of (meth) acrylate having a temperature of -20 ° C. or less and 100% by weight of a total of 0 to 10% by weight of comonomer copolymerizable therewith. It is an acid ester resin, and methacrylic acid ester resin consists of particle | grains which have a core-cell structure, The core layer contains 70 weight% or more of homopolymers of methyl methacrylate, or a methyl methacrylate unit. The glass transition point of homopolymer is -20 ℃ or less Ta) acrylate unit is composed of a copolymer containing 30% by weight or less, the cell layer is composed of a copolymer containing 20 to 50% by weight of the unit of (meth) acrylate having a glass transition point of the homopolymer of -20 ℃ or less. The amount of the (meth) acrylate unit in the copolymer which comprises a cell layer is more than the amount of the (meth) acrylate in the said copolymer which comprises a core layer, The vinyl chloride type resin composition is provided.

In another aspect of the present invention, 100 parts by weight of (A) vinyl chloride resin, 5 to 30 parts by weight of (B) methacrylate resin, and (D) 5 to 150 parts by weight of wood powder having an average particle diameter of 50 to 500 µm. The mixture was added to a mixer, the mixture was heated to 120 to 160 ° C, and then the mixture was transferred to a cooling mixer, followed by cooling by adding 0.1 to 3.0 parts by weight of the (C) pyrolysis blowing agent, followed by mixing. As the resin, 65 to 88% by weight of methyl methacrylate, 35 to 12% by weight of (meth) acrylate having a glass transition point of homopolymer of -20 ° C or lower, and 0 to 10% by weight of comonomer copolymerizable with these, if necessary It is composed of 100% by weight monomer units, has a specific viscosity of 1.5 to 4.0, and is composed of particles having a core-cell structure. The core layer is a homopolymer of methyl methacrylate or a methyl methacrylate unit. More than 70% by weight homopolymer Is composed of a copolymer containing 30% by weight or less of (meth) acrylate units having a glass transition point of -20 ° C or less, and the cell layer comprises 20 to 20 units of (meth) acrylate having a glass transition point of homopolymer of -20 ° C or less. A methacrylic acid ester-based resin which is composed of a copolymer containing 50% by weight and whose amount of (meth) acrylate units in the copolymer constituting the cell layer is higher than the amount of (meth) acrylate in the copolymer constituting the core layer. It provides a method for producing a vinyl chloride-based resin composition, characterized in that using.

(The best form to carry out invention)

Hereinafter, the present invention will be described in detail.

In the composition of the present invention, the vinyl chloride resin used as the component (A) includes a copolymer containing 50% by weight or more of vinyl chloride in addition to the vinyl chloride homopolymer. As comonomer in the case of a vinyl chloride copolymer, For example, olefins, such as ethylene and propylene; Halogenated olefins such as aryl chloride, vinylidene chloride, vinyl fluoride and ethylene trifluorochloride; Carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as isobutyl vinyl ether and cetyl vinyl ether; Aryl ethers such as aryl-3-chloro-2-oxypropyl ether and aryl glycidyl ether; Unsaturated carboxylic acids such as acrylic acid, maleic acid, itaconic acid, 2-hydroxyethyl acrylate, methyl methacrylate, monomethyl maleate, diethyl maleate, maleic anhydride, esters thereof or acid anhydrides thereof; Unsaturated nitriles such as acrylonitrile and methacrylonitrile; Acrylamides such as acrylamide, N-methylol acrylamide, acrylamide-2-methylpropanesulfonic acid and (meth) acrylamidepropyltrimethylammonium chloride; Allylamine, such as an arylamine benzoate and a diaryl dimethyl ammonium chloride, its derivatives, etc. are mentioned.

The monomers exemplified above are only a part of the copolymerizable monomers, and various monomers exemplified on the Kinki Chemical Association Vinyl Subpart “Polyvinyl Chloride” Daily Industrial News, Ltd. (1988), pages 75 to 104 can be used. Moreover, the resin which graft-polymerized the vinyl chloride or vinyl chloride and said copolymerizable monomer to resin, such as an ethylene-vinyl acetate copolymer, an ethylene-methylmethacrylate copolymer, an ethylene-ethyl acrylate copolymer, and chlorinated polyethylene, is also contained. .

These vinyl chloride-based resins may be made by any known manufacturing method, such as suspension polymerization, emulsion polymerization, solution polymerization, or bulk polymerization. The average degree of polymerization of the vinyl chloride-based resin is preferably 400 to 1,500, more preferably 600 to 1100 in the measuring method of JIS K 6721. If the average degree of polymerization of the vinyl chloride-based resin is less than 400, the foaming ratio tends to be difficult to rise, whereas if the average degree of polymerization of the vinyl chloride-based resin is greater than 1,500, many coarse ones may be mixed in the foaming cells.

In the present invention, as the component (B), 65 to 88% by weight of methyl methacrylate, 35 to 12% by weight of (meth) acrylate having a glass transition point of the homopolymer of -20 ° C or less, and a copolymer copolymerizable with these as necessary. Methacrylic acid ester resin which is comprised from the monomer unit of 100 weight% of monomers total of 0-10 weight%, and whose specific viscosity is 1.5-4.0 is used. Here, (meth) acrylate means acrylate or methacrylate. As (meth) acrylate which gives a homopolymer whose glass transition point is -20 degrees C or less, for example, ethyl acrylate (glass transition point of a homopolymer -22 degreeC), n-propylacrylate (copper-52 degreeC), n-butyl Acrylate (copper-54 ° C), isobutyl acrylate (copper-24 ° C), n-octylacrylate (copper-65 ° C), 2-ethylhexyl acrylate (copper-85 ° C), methoxyethylacrylate (Copper -85 degreeC), ethoxyethyl acrylate (copper -50 degreeC), n-octyl methacrylate (copper -20 degreeC), n-decyl methacrylate (copper -65 degreeC), n-lauryl meta Acrylate (copper-65 ° C.) and the like. 1 type may be used for these (meth) acrylates, and 2 or more types may be used in combination. In particular, n-butylacrylate is preferable.

Moreover, as a monomer copolymerizable with (meth) acrylate which gives methyl methacrylate and the homopolymer whose glass transition point is -20 degrees C or less, aromatic vinyl compounds, such as styrene, vinyltoluene, and (alpha) -methylstyrene; (meth) acryl Vinyl cyanide compounds such as nitrile and vinylidene cyanide; And 2-hydroxyethyl methacrylate, hydroxybutyl vinyl ether, monobutyl maleate, glycidyl methacrylate, butoxyethyl methacrylate, and the like.

The monomer composition as the whole particle | grains of methacrylic acid ester-type resin which is (B) component is 65-88 weight% of methyl methacrylate units, Preferably it is 70-85 weight%, The glass transition point of a homopolymer is -20 degrees C or less, Preferably it is 35-12 weight% of a (meth) acrylate unit which is -30 degrees C or less, Preferably it is 30-15 weight%, Moreover, if necessary, it contains 0-10 weight% of comonomer units copolymerizable with these, 100 weight% in total. If the content of the methyl methacrylate unit is less than 65% by weight, the foaming ratio of the foamed molded product does not increase.On the contrary, if the content of the methyl methacrylate unit is more than 88% by weight, the fusion of wood powder of the methacrylic acid ester resin deteriorates and the wood powder aggregates or the foam cell size. Is nonuniform, resulting in a nonuniform composition of the molded article.

The methacrylic acid ester-based resin (B) is a particle having a core cell structure, the core layer of which is 70% by weight or more of methyl methacrylate homopolymer or methyl methacrylate unit, and the glass transition point of the homopolymer. It consists of a copolymer containing 30 weight% or less of (meth) acrylate units which are 20 degrees C or less, and the cell layer contains 20-50 weight% of (meth) acrylate units whose glass transition point of a homopolymer is -20 degrees C or less. The amount of the (meth) acrylate units in the copolymer constituting the cell layer is greater than the amount of the (meth) acrylate units in the copolymer constituting the core layer. Resin which has such a core cell structure has the core cell structure also in preparation of a composition besides the advantage of performing latex coagulation after superposition | polymerization at the comparatively low temperature of 55-80 degreeC in manufacture of methacrylic acid ester resin of (B) component. The particles possessed are easily fused to wood flour, and the uniformity of mixing and dispersing is improved, so that further homogenization of the foamed molded article can be achieved. In the core-cell particle | grains which comprise methacrylic acid ester type resin which is (B) component, 1 / 1-15 / 1 are preferable for the weight ratio of a core and a cell.

The methacrylic acid ester resin used as the component (B) needs to have a specific viscosity of 1.5 to 4.0 at 25 ° C. of 100 ml of a chloroform solution in which 0.2 gr is dissolved, and is preferably in the range of 2.0 to 3.0. If the specific viscosity value is less than 1.5, the surface of the molded article is rough, and if it exceeds 4.0, time is required for uniform melting. In order to control the specific viscosity, a general method such as selecting a polymerization temperature and using a salt transfer agent such as t-dodecylmedcaptan and carbon tetrachloride can be adopted.

Methacrylic acid ester-based resin of component (B) improves the melt viscosity characteristics of vinyl chloride-based resin, disperses wood powder uniformly in vinyl chloride-based resin, maintains film strength of foaming cell and makes it difficult to break. have.

(B) component compounding quantity in this invention is 5-30 weight part per 100 weight part of vinyl chloride-type resin of the said (A) component, Preferably it is 10-20 weight part. If the amount of the component (B) is less than 5 parts by weight, the film strength holding force during foaming is weakened and the foaming cells are easily broken. In addition, when the blending amount exceeds 30 parts by weight, the melt viscosity is increased, the heat generation is large, and thermal deterioration of the resin is likely to occur, and the foam cell size is likely to be nonuniform.

As a thermal decomposition type foaming agent which is (C) component of the composition of this invention, a thermal decomposition type organic foaming agent and / or a thermal decomposition type inorganic foaming agent are used. Examples of the former include nitroso compounds such as N, N'-dinitropentamethyleneteramine and N, N'-dimethyl-N, N'-dinitrosotelephthalamide; Azo compounds such as azodicarbonamide, azobisisophthalonitrile, sulfonylhydrazides such as benzenesulfonylhydrazide, P, P'-oxybis (benzenesulfonylhydrazide), toluenesulfonylhydrazide, etc. Can be mentioned. Examples of the latter include sodium bicarbonate, ammonium bicarbonate, ammonium carbonate and the like. The present invention may use one or two or more selected from the group of organic and / or inorganic pyrolytic blowing agents.

In the present invention, low boiling point organic compounds such as trifluoromethane and petroleum ether are heated and volatilized to be used for the blowing agent. This is because the foam cell becomes rough and the molded product is hardly fixed or the bistable is difficult to be suitable for building materials.

The thermal decomposition type foaming agent compounding quantity of (C) component in this invention is 0.1-3.0 weight part per 100 weight of vinyl chloride-type resin of (A) component, Preferably it is 0.5-1.5 weight part. If the amount of component (C) is less than 0.1 part by weight, the foaming ratio is small, and thus the inside of the molded product obtained tends to lack wood texture. On the contrary, when the content of the component is more than 3.0 parts by weight, the surface of the molded product tends to be rough or the surface hardness tends to decrease.

In the present invention, the wood powder having an average particle diameter of 50 to 500 µm as the component (D) is 5 to 150 parts by weight, preferably 22 to 120 parts by weight, more preferably 25 to 100 parts by weight of 100 parts by weight of the vinyl chloride resin (A). Parts by weight are used. If the amount of the wood powder is less than 5 parts by weight, it is difficult to express the wood texture in the molded article, and if it exceeds 150 parts by weight, the molded article becomes fragile. In the present invention, by blending the above-mentioned (B) component, even if the wood powder is blended in a high quantity of more than 20 parts by weight, it is easy to fuse to the vinyl chloride-based resin and can be dispersed uniformly. It has a smooth epidermis and can express strongly wood texture.

The wood flour species used in the present invention are not particularly limited, and wood such as sapwood such as cedar, pine, nawang, and hardwood lumber, sawdust, and wild rice. In order to obtain (D) component of this invention from these woods, it is good to make the wood into comparatively round wood powder with an average particle diameter of 500 micrometers or less, for example.

The wood powder used in the present invention may be wood powder having a small particle firmly attached to the surface, as disclosed in Japanese Patent Laid-Open Nos. 5-177610 and 5-261708. Hard particle | grains are particle | grains whose hardness is larger than wood powder and whose average particle diameter is smaller than the particle size of wood powder, A metal, a metal oxide and a metal salt, an inorganic compound, a plastic particle, etc. are mentioned specifically ,. Preferred component (D) is wood powder having inorganic or metal particles such as titanium oxide, nickel, calcium carbonate, silica and mica attached to the surface. The mode in which hard particles are attached to the surface of the wood powder is solid wood particles, such as a bonding bond including a dent of hard particles to the wood powder, and an interlocking bond by a plurality of hard small particles that are pierced. The adhesion by external force pressurized against the surface may be sufficient, or hard particle | grains may be made to adhere to wood powder with an adhesive agent. In this case, the wood powder is placed in a ball mill or the like with 1 to 50% by weight of small particles, and treated under conditions that prevent dust explosion, such as nitrogen atmosphere.

The average particle diameter of (D) component used for this invention is 50-500 micrometers, Preferably it is 30-100 micrometers. Here, the average particle diameter is obtained by screen analysis on the powder to obtain a cumulative weight percent curve for eye opening, and to read the value of eye opening corresponding to the 50% by weight. If the average particle diameter of (D) component is smaller than 50 micrometers, a volume specific gravity will become small, the mixing operation for composition preparation will worsen, and when larger than 500 micrometers, the molded article surface will be rough and foaming ratio will fall. The moisture in the component (D) is preferably 10% by weight or less, more preferably 5% by weight or less.

In addition to each of the above components, a UV absorber, an impact strengthening agent, a pigment, a plasticizer, an antistatic agent, and the like are appropriately added to the composition of the present invention, in addition to the heat stabilizer or lubricant used in processing of normal vinyl chloride resin.

In preparing the composition of the present invention, the components (A), (B) and (D), except for the thermal decomposition type blowing agent of the component (C), are firstly collectively added to a mixer such as a Henschel mixer, preferably severely. It heats up at 120-160 degreeC, mixing by stirring. In this mixing process, the moisture absorbed in the wood powder is volatilized. When the temperature is reached, the mixture is transferred to a cooling mixer, and cooled by adding a thermal decomposition type blowing agent of component (C). Usually, temperature is reduced to about 50-60 degreeC. The powdered mixture taken out can be used as a molding compound as it is, but is usually pelletized. Preferred methods for pelletizing include a method for producing pellets using a twin screw extruder at 150 to 170 DEG C and discharging the residual moisture in the wood powder from the vent hole.

In the above-mentioned composition preparation method of the present invention, a mixture of all components except the foaming agent is added in a batch at the time of the first mixing in a Henschel mixer or the like, whereby a mixture having a high volume specific gravity and uniformly dispersed additives such as pigments can be obtained.

Using the composition of the present invention, the molding method for obtaining a vinyl chloride-based resin molded article similar to natural wood is not particularly limited, but extrusion molding is usually employed. The extrusion molding conditions are the same as those of extrusion molding of general vinyl chloride resin.

The extruded foamed article thus obtained has fine cells uniformly distributed. Usually, the average diameter of a cell is 100 micrometers or less. Moreover, as for the expansion ratio of an extrusion foamed molded article, 1.5-2.0 are preferable. If the foaming ratio is too low, the texture is degraded. On the contrary, if the foaming ratio is too high, the mechanical strength is lowered. What is necessary is just to form the extrusion molded product according to the use of building materials, furniture materials, etc., and generally a plate shape, a sheet shape, a columnar shape, columnar mold release, etc. are mentioned.

(Examples and Comparative Examples)

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Incidentally, parts and percentages are based on weight.

Methacrylic acid ester system A-G was prepared as follows. The specific viscosity of each resin was sampled from 100 ml of chloroform solution in which 0.2 gr of resin was dissolved, and measured at 25 ° C.

Methacrylic acid ester resin production example 1

Emulsion polymerization was carried out at a polymerization temperature of 55 ° C. while stirring and stirring 60 parts of methyl methacrylate, 15 parts of n-butyl acrylate, 1 part of alkyl sodium sulfate having 12 to 18 carbon atoms, 0.1 part of potassium persulfate and 150 parts of water to a stainless reactor. Was performed. The completion | finish of reaction was confirmed by solid content concentration of the sampled reaction liquid, 15 parts of methacrylates were completed to the obtained latex (using polymer particle as nucleus), and the latex of 40.2% of solid content concentration was obtained.

The obtained latex was salted by adding aluminum sulfate under heating, dehydrated, washed and dried to obtain Resin A. The composition and specific viscosity of the resin A are shown in Table 1.

Methacrylic acid ester resin production example 2

Instead of 25 parts of n-butyl acrylate, 30 parts of ethyl acrylate is used, and 55 parts of methyl methacrylate and 20 parts of ethyl acrylate are used as monomers to be added during the first stage polymerization. The same procedure as in Production Example 1 of Methacrylic Acid Ester Resin was carried out except that 0.1 part of t-dodecyl mercaptan was added and 15 parts of methyl methacrylate and 10 parts of ethyl acrylate were used as monomers to be added during the second stage polymerization. And resin B were obtained. The composition and specific viscosity of Resin B are shown in Table 1.

Methacrylic acid ester resin production example 3

Instead of 25 parts of n-butyl acrylate type, 20 parts of n-butyl methacrylate type is used, and 65 parts of methyl methacrylate and 10 parts of n-butyl methacrylate are used as monomers to be added during the first stage polymerization. Further, 0.03 parts of t-dodecyl mercaptan is added, and 15 parts of methyl methacrylate and 10 parts of n-butyl methacrylate (20 ° C of glass transition point of homopolymer) as monomers to be added during the second stage polymerization. Except what was used, it carried out similarly to the methacrylic acid ester-type resin manufacture example 1, and obtained resin C. The composition and specific viscosity of the resin C are shown in Table 1.

Methacrylic acid ester resin production example 4

93 parts of methyl methacrylate, 7 parts of ethyl acrylate, 0.05 parts of t-dodecyl mercaptan, 1 part of alkyl sodium sulfate of 12 to 18 carbon atoms, 0.1 part of potassium persulfate and 150 parts of water were added to the stainless reactor, and stirred. The emulsion was polymerized at 70 ° C. while the completion of the reaction was confirmed by the solid concentration of the sampled reaction solution.

The obtained latex was salted by adding aluminum sulfate under heating, dehydrated, washed and dried to obtain Resin D. The composition and specific viscosity of the resin D are shown in Table 1.

Methacrylic acid ester resin production example 5

As the monomer for the polymerization reaction, 60 parts of methyl methacrylate and 40 parts of n-butyl acrylate were used, and the amount of t-dodecyl mercaptan was changed to 0.07 parts. It carried out and obtained resin E. The composition and specific viscosity of the resin E are shown in Table 1.

Methacrylic acid ester production example 6

As the monomer for the polymerization reaction, 75 parts of methyl methacrylate and 25 parts of n-butyl acrylate were used, and the amount of t-dodecyl mercaptan was 0.20 parts. It carried out and obtained resin F. The composition and specific viscosity of the resin F are shown in Table 1.

Methacrylic acid ester resin manufacture example 7

Without adding t-dodecyl mercaptan, instead of 0.1 part of potassium persulfate as a radical initiator, 0.20 part of cumene hydroperoxide, 0.1 part of sodium formaldehyde sulfoxylate, 0.02 part of iron ethylenediamine tetraacetate and sodium ethylenediamine tetraacetate 0.01 Resin G was obtained by carrying out similarly to 6 in the manufacture of methacrylic acid ester-type resin except having used the part and making reaction temperature into 5 degreeC. The composition and specific viscosity of resin G are shown in Table 1.

Foamed article properties were investigated by the following method.

1) Foam cell state

The cut surface of the molded article was observed with an optical microscope and evaluated as the following 4 grades.

A: The cell diameter is a fine and uniform state of 100 µm or less.

B: Cells that are destroyed and roughened are rarely found.

C: Many cells are destroyed and roughened.

D: Most of the cells that are destroyed and roughened.

2) Molded product surface properties

It evaluated by the following 4 grades by visual and finger touch of the molded article surface.

A: smooth

B: slightly rough skin

C: rough skin

D: Many granular projections.

3) Specific gravity and specific gravity of molded products

It is measured by the submerged method according to JIS K 7112.

4) Foam rate of molded products

It is calculated | required by the following formula using the value of specific gravity by the said measurement.

Foaming ratio = Partial weight / Molded product weight

5) tensile strength

The test piece of JIS K 7113 No. 1 is measured at a tensile rate of 10 mm / minute.

Examples 1-3 and Comparative Examples 1-8

Each component of the kind and quantity shown in Table 2 was mix | blended with the following trick in a Henschel mixer. A vinyl chloride resin, a methacrylic acid ester resin (except for Comparative Example 1), wood flour, a heat stabilizer, a lubricant, a filler, and a pigment were added thereto, followed by vigorous stirring and mixing to vaporize the water vapor. When the temperature rose to 140 ° C, the mixture was transferred to a cooling mixer and mixed, a blowing agent was added at 100 ° C, and the temperature was lowered to 60 ° C. The obtained powdery mixture was pelletized under the following conditions using a uniaxial extruder having a cylinder diameter of 65 mm. In addition, the moisture remaining in the wood powder was volatilized from the vent hole.

Screw: L / D = 24, Compression Ratio 2.5, Speed 30rpm

Set temperature: C ₁ = 130 ℃, C ₂ = 140 ℃, C ₃ = 150 ℃

C ₄ = 160 ° C, head 160 ° C, dies 160 ° C

Dies: 3 mm Φ pellet x 12 holes

Land Length: 10mm

The pellets thus obtained were extruded and molded under the following conditions by a single screw extruder having a cylinder diameter of 40 mm. The molded article characteristics are shown in Table 1.

Screw: L / D = 22, Compression Ratio 2.5, Speed 25rpm

Set temperature: C ₁ = 140 ℃, C ₂ = 160 ℃, C ₃ = 170 ℃, C ₄ = 180 ℃, Head 160 ℃, D ₁ = 160 ℃, D ₂ = 160 ℃

Dies: thickness 4 mm width x 50 mm belt

Land Length: 5mm

Suzy  Composition weight ratio  Boiling point MMA nBA E A nBMA  A  75  25   -   -    3.3  B  70   -  30   -    1.8  C  80   -   -   20    2.6  D  93   -   7   -    2.2  E  60  40   -   -    2.4  F  75  25   -   -    1.1  G  75  25   -   -    4.2  Main MMA Methyl methacrylate nBA n-butylacrylate EA Ethyl acrylate nBMA n-butyl methacrylate

Examples 1 to 3 molded using the composition satisfying the requirements of the present invention resulted in a molded article having a good foaming cell state and surface properties, having sufficient foaming ratio, abundant wood texture, and satisfying tensile strength. .

In Comparative Example 1 in which the methacrylic acid ester resin was not blended, the foam cell state, surface properties, and foaming ratio were all poor.

As methacrylic acid ester resin, Comparative Example 2 or 3 using resin C which contains a comonomer unit whose glass transition point is higher than a prescribed range, and resin D which has a low content even if it is a copolymer in a prescribed range is foamed The cell became coarse, the foaming ratio did not rise, and the molded article had a rough skin. In addition, the use of methacrylic acid ester-based resin E containing more comonomers having a glass transition point in the specified range than the specified ratio yielded a molded article having a high foaming ratio but a rough foamed surface and a rough surface property, resulting in poor saddle strength ( Comparative Example 4). Even when the methacrylic acid ester system containing a prescribed amount of the comonomer at the specified glass transition temperature is out of the specified range, it becomes small or large, or a molded article with a foamed cell state and a molded article surface (Comparative Example 5, 6).

When the compounding quantity of methacrylic acid ester-type resin was too small or excessive, it became a foamed cell or the molded article which passed through the surface remarkably (comparative example 7,8).

(Industrial availability)

The vinyl chloride-based resin composition molded article of the present invention has a uniform fine foamed cell structure and a smooth skin, and is rich in wood texture and has sufficient mechanical strength.

Therefore, this molded article is suitable as building materials and furniture materials.

Claims (8)

100 parts by weight of (A) vinyl chloride-based resin, 5-30 parts by weight of (B) methacrylic acid ester resin, (C) 0.1-3.0 parts by weight of thermal decomposition foaming agent, and (D) wood powder having an average particle diameter of 50-500 μm 5 As a vinyl chloride-based resin composition containing -150 parts by weight, This methacrylic acid ester resin is 65 to 88% by weight of methyl methacrylate, 35 to 12% by weight of (meth) acrylate having a glass transition point of homopolymer of -20 ° C or less, and comonomers copolymerizable therewith as required. It is methacrylic acid ester-type resin which is comprised from 100 weight% of monomeric units of -10 weight% in total, and has a specific viscosity of 1.5-4.0, and this methacrylic acid ester-type resin consists of particle | grains which have a core-cell structure. The core layer is made of a homopolymer of methyl methacrylate, or air containing at least 70% by weight of methyl methacrylate units and 30% by weight or less of (meth) acrylate units having a glass transition point of homopolymer of not more than -20 ° C. It is composed of a copolymer, the cell layer is composed of a copolymer containing 20 to 50% by weight of units of (meth) acrylate having a glass transition point of homopolymer of -20 ° C or less, ) Acrylate units of the copolymer to the amount constitutes a core layer of the (meth) acrylate amounts to many of the characteristics of a vinyl chloride-based resin composition for more. The vinyl chloride resin composition according to claim 1, wherein the average degree of polymerization of the vinyl chloride resin is 400 to 1,500. The vinyl chloride resin composition according to claim 1 or 2, wherein the specific viscosity at 25 ° C of 100 ml of the chloroform solution in which the methacrylic acid ester resin is dissolved 0.2 gr is 2.0 to 3.0. The vinyl chloride-based resin composition according to claim 1 or 2, wherein the weight ratio of the core and the cell is 1/1 to 15/1. The vinyl chloride resin composition according to claim 1 or 2, wherein the amount of the wood powder is 22 to 120 parts by weight. 100 parts by weight of (A) vinyl chloride resin, 5 to 30 parts by weight of (B) methacrylic acid ester resin, and (D) 5 to 150 parts by weight of wood powder having an average particle diameter of 50 to 500 µm were added to a mixer and mixed. The temperature is raised to ˜160 ° C., and then the mixture is transferred to a cooling mixer, followed by cooling by adding 0.1 to 3.0 parts by weight of the (C) pyrolysis blowing agent, followed by mixing. As the methacrylic acid ester resin, 65 to 88% by weight of methyl methacrylate, 35 to 12% by weight of (meth) acrylate having a glass transition point of the homopolymer of -20 ° C or less, and comonomers copolymerizable therewith as required 0 It consists of the monomer unit of 100 weight% of total of -10 weight%, the specific viscosity is 1.5-4.0, and is comprised from the particle which has a core-cell structure, The core layer is a homopolymer of methyl methacrylate, or It is composed of a copolymer containing at least 70% by weight of methyl methacrylate units and at most 30% by weight of (meth) acrylate units having a glass transition point of homopolymer of -20 DEG C or less, and the cell layer has a glass transition point of homopolymer- It is composed of a copolymer containing 20 to 50% by weight of units of (meth) acrylate which is 20 ° C. or less, and the amount of (meth) acrylate units in the copolymer constituting the cell layer constitutes the core layer. A method for producing a vinyl chloride resin composition, characterized by using more methacrylic acid ester resins than the amount of (meth) acrylate. The method for producing a vinyl chloride-based resin composition according to claim 6, wherein the cooling mixer is cooled to 50 to 60 DEG C or lower while adding and mixing the (C) pyrolysis blowing agent. The method for producing a vinyl chloride-based resin composition according to claim 6 or 7, wherein after cooling, the mixture is taken out of a cooling mixer and pelletized in an extruder.