JPH0881607A - Production of polyvinyl chloride-based resin composition - Google Patents

Abstract

PURPOSE: To obtain a polyvinyl chloride-based resin composition capable of suppressing aggregation of wood powder and generation of acidic gas and having stable extrusion moldability and useful as a substitute material for wood by blending a mixture obtained by preliminarily mixing wooden powder with a metal soap or a lead compound with a polyvinyl chloride-based resin, etc. CONSTITUTION: This composition is obtained by preliminarily mixing (B) 100 pts.wt. of wooden powder with (C) >=0.5 pts.wt. of a metal soap or a lead compound and adding the component A and the component C in a ratio of <=20 pts.wt. of the component C based on 100 pts.wt. of the component A to the resultant mixture or mixing the component A with the component C and then mixing the mixture with the resultant mixture.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vinyl chloride resin composition.

[0002]

2. Description of the Related Art In recent years, various attempts have been made to use synthetic resin compositions as substitute materials for wood by imparting properties close to those of natural wood. As one of the methods, there is a method of adding a powdery woody material to a synthetic resin as a compounding agent. Such a wood substitute material can be an effective material for applications such as interior materials for homes, furniture materials, and structural materials with high rigidity.

[0003] However, since the woody material is poorly compatible with the resin in the molten resin and easily aggregates, the dispersion in the resin becomes nonuniform, and therefore the addition of the woody material generally lowers the strength and appearance of the molded body. Will be invited. Furthermore, the addition of the wood-based material has a problem in that it is caught on the inner surface of the molding machine, causing so-called "build-up", or scratching the inner surface of the molding machine. Further, since the wood-based material generates an acid gas when heated, there is a problem that the molding machine gradually corrodes and shortens its life. Further, when added to the polyvinyl chloride resin, there is a problem that the acidic gas generated from the woody material accelerates the deterioration reaction of the resin and colors the molded body.

In order to solve these problems, a method of neutralizing the generated acidic gas with a urea resin to render it harmless is disclosed (Japanese Patent Laid-Open No. 55-116752).
JP-A-61-2505). However, with this method, the odor derived from the urea-based resin remains in the product, which is not suitable for interior materials for houses.

Further, there is disclosed a method of suppressing the generation of acid gas by coating the surface of wood powder with a white inorganic pigment or the like using a ball mill (Japanese Patent Laid-Open No. 5-17761).
No. 0). However, in this method, only the effect of covering the surface of the wood powder, essentially, it is not possible to suppress the generation of acid gas, the more wood powder added to the resin, the more adverse effect of acid gas. There was a problem that it became remarkable.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and an object thereof is polychlorination that effectively suppresses an acidic gas generated from a wood material and does not impair the moldability. It is to provide a method for producing a vinyl resin composition.

[0007]

The method for producing a vinyl chloride resin composition of the present invention is a method for producing a polyvinyl chloride resin composition comprising a polyvinyl chloride resin (a) and a wood powder (b). In addition, the wood powder (b) is preliminarily mixed with the metal soap (c) and / or the lead-based compound (d).

As the polyvinyl chloride resin (a), those conventionally known as foam moldings can be used. For example, a homopolymer of vinyl chloride or a polymer other than vinyl chloride and vinyl chloride. Copolymers with water-soluble monomers, graft copolymers obtained by grafting vinyl chloride onto polymers other than vinyl chloride; chlorination obtained by post-chlorinating these (co) polymers by a conventionally known method. Vinyl chloride resin; a mixture of the (co) polymer and chlorinated vinyl chloride resin, and the like.

The polymerizable monomer other than vinyl chloride is not particularly limited as long as it has a reactive double bond, and for example, α-such as ethylene, propylene and butylene.
Olefin; Vinyl acetates such as vinyl acetate and vinyl propionate; Vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; Methyl acrylate
Acrylic acid esters such as ethyl acrylate; Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, phenyl methacrylate; styrene, α
-Aromatic vinyls such as methylstyrene; vinyl halides such as vinylidene chloride and vinyl fluoride; N- such as N-phenylmaleimide and N-cyclohexylmaleimide
Substituted maleimides and the like may be used alone or in combination of two or more.

The polymer other than vinyl chloride used in the graft copolymer is not particularly limited, and examples thereof include ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene. -Ethyl acrylate copolymer, ethylene-ethyl acrylate-carbon monoxide copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, acrylonitrile-butadiene copolymer, polyurethane resin, chlorinated polyethylene resin, chlorine And the like. These may be used alone or in combination of two or more.

If the average degree of polymerization of the above polyvinyl chloride resin is small, the mechanical properties of the obtained molded product will be insufficient, and if it is large, the melt viscosity at the time of molding will be high and molding will be difficult. , 000 is preferable, and 400 to 800 is more preferable particularly when foam molding is performed.

As the wood powder (b), natural wood,
Rice husks, those made by atomizing those composed of natural cellulosic fibers such as pulp by a known method, as the natural wood, for example, those commonly used as wood such as stalks, cypress, pine, and lauan. It is preferably used.

When the average particle size and the maximum particle size of the wood powder (b) become large, the wood powder stays inside the molding machine and becomes "clogged".
The average particle size is 300 because it may cause burns
It is preferably not more than 100 μm, more preferably not more than 100 μm, and the maximum particle size is preferably not more than 500 μm.

If the water content of the above wood powder (b) increases, water bubbles during molding to roughen the surface of the molded body,
Since it accelerates the deterioration of the resin during molding, it is preferably 10% by weight or less.

In the polyvinyl chloride resin composition, when the amount of the wood powder (b) used is small, it is difficult to impart properties close to those of natural wood, and when the amount is large, the melt viscosity of the resin increases and molding becomes difficult. Therefore, it is limited to 5 to 80 parts by weight with respect to 100 parts by weight of the polyvinyl chloride resin.

In the production method of the present invention, the surface of the wood powder (b) is previously coated with the wood powder (b) so that the surface is coated with the metal soap (c) and / or the lead compound (d). The metal soap (c) and / or the lead-based compound (d) are premixed.

The metal soap (c) is a metal salt of a higher fatty acid, and examples of the metal include lithium, magnesium, calcium, strontium, barium, cadmium and zinc. Examples of higher fatty acids include stearic acid, lauric acid, ricinoleic acid, naphthenic acid, 2-ethylhexoisoic acid and the like.

Examples of the metal soap (c) include lithium stearate, magnesium stearate, calcium stearate, calcium laurate, calcium ricinoleate, strontium stearate, barium stearate, barium laurate, barium ricinoleate, stearic acid. Cadmium, cadmium laurate, cadmium naphthenate, cadmium 2-ethylhexisoisoate, zinc stearate, zinc laurate, zinc ricinoleate, zinc 2-ethylhexisoate, and the like, which may be used alone or in combination of two or more. May be used in combination.

Examples of the lead compound (d) include:
Lead white, basic lead sulfite, dibasic lead sulfite, tribasic lead sulfate, dibasic lead phosphite, silica gel co-precipitated lead silicate, lead stearate, lead benzoate, dibasic lead stearate,
Examples thereof include lead naphthenate, and these may be used alone or in combination of two or more kinds.

In the polyvinyl chloride resin composition, if the amount of the metal soap (c) and / or the lead compound (d) used is reduced, the surface of the wood powder (b) cannot be sufficiently covered. Therefore, there is no effect of suppressing the deterioration of the resin, and if the amount is large, the moldability and heat resistance may be impaired, and the appearance of the molded product may be deteriorated. Therefore, with respect to 100 parts by weight of the polyvinyl chloride resin (a), It is limited to 20 parts by weight or less, and preferably 0.5 parts by weight or more based on 100 parts by weight of the wood powder (b).

Additives such as stabilizers, stabilizing aids, release agents, foaming agents, pigments, fillers and the like may be added to the polyvinyl chloride resin composition. The stabilizer is added at the time of mixing the polyvinyl chloride resin (a) and the wood powder (b) in order to obtain sufficient heat stability during molding, and as the stabilizer, wood powder ( Metal soap (c) and / or lead-based compound (d) used during premixing with b)
May be used, and other stabilizers may be used.

Examples of the other stabilizers include organic tin compounds such as dibutyltin malate and dioctyltin laurate. When the lead-based compound (d) is used, other stabilizers include calcium stearate,
Metal soaps such as barium stearate and zinc stearate can also be used. However, the stabilizer having a mercapto group is not preferable because it reacts with the lead-based compound (d) to form a sulfide and contaminates the molded body.

When the above-mentioned metal soap (c) is used, in order to improve the effect of the metal soap (c) as a stabilizer, it is possible to stabilize the epoxy compound, phosphite, β-diketone, polyol and the like. A chemical assistant may be used in combination.

If desired, additives other than the above stabilizers may be premixed with the wood powder (b) in advance. For example, in order to prevent the wood powder (b) from being scattered during mixing, a plasticizer such as dioctyl phthalate and the metal soap (c) and / or the lead compound (d) may be premixed at the same time.

The method for producing a polyvinyl chloride resin composition of the present invention comprises: (a) mixing wood powder (b) with metal soap (c) and / or lead compound (d) to obtain wood powder (b). (2) a step of coating the surface of (1), (b) a surface-treated wood powder (b) and a polyvinyl chloride resin (a), and optionally additives and simultaneously mixing them You may go in.

Further, in the above-mentioned manufacturing process, (c) a step of mixing the wood powder (b) with the metal soap (c) and / or the lead compound (d) to coat the surface of the wood powder (b). ,
It is carried out in three steps: (d) a step of mixing the polyvinyl chloride resin (a) and the additive, and (e) a step of mixing the mixtures obtained in the above (c) and (d) together. You may break.

As a device used for mixing the respective components in the above manufacturing process, a generally known mixing device can be used. For example, a flat plate type, a propeller type, a Fidler type stirring blade is rotated in a mixing tank. Mixer with structure
A ball mill having a structure in which a stirring ball is made to flow in a mixing tank;
Crushing machine; shakers and the like.

An extrusion molding method is used for molding the above vinyl chloride resin composition, and any extruder may be used as the extrusion molding method, such as a single-screw extruder or a twin-screw extruder. It is preferably used.

In the case of molding by an extruder, the molding temperature is
The linder temperature is the supply side temperature (hereinafter C ₁Called), the central side
Temperature (hereinafter C₂Discharge temperature (hereinafter C₃Toi
), The temperature of the adapter that connects the extruder and the die (hereinafter A
D) and mold temperature (hereinafter D)
Set to the temperature of.

[0030]

Embodiments of the present invention will be described below. [Preparation of Preliminary Mixture of Wood Powder] The predetermined amounts of wood powder (b) and metal soap (c) shown in Table 1 were put in a super mixer (20 liters, manufactured by Kawada Kogyo Co., Ltd.), and 40 to 8
Pre-treatment was carried out by mixing at 0 ° C. for 1 hour. The following materials were used as the wood powder (b), the metal soap (c) and the stabilizing aid. -Wood powder (b): Wood for building materials is dried and crushed, water content 5.0% by weight, average particle size 100 μm (maximum particle size 30
0 μm). Metallic soap (c): 1) Calcium stearate (SC-10 manufactured by Sakai Chemical Co., Ltd.
0 ”). 2) Zinc stearate ("SZ-200" manufactured by Sakai Chemical Industry Co., Ltd.
0 ”). -Stabilizing aid: 1) Trisnonylphenyl phosphite ("Adeka Stub 329" manufactured by Asahi Denka Co., Ltd.). 2) Dialkyl monoallyl phosphite (“Adeka Stub 517” manufactured by Asahi Denka Co., Ltd.). (Similar wood powder, metal soap and stabilizing aid are used in the following examples.)

[0031]

[Table 1]

(Examples 1 to 6, Comparative Examples 1 and 2) A predetermined amount of polyvinyl chloride resin (a), wood powder (b) (preliminary mixture), metal soap (c) and The stabilizing aid was put in a super mixer and mixed at 70 to 120 ° C. for 15 minutes to prepare a polyvinyl chloride resin composition.

[0033]

[Table 2]

In Table 2, the following were used. -Polyvinyl chloride resin: average degree of polymerization 1000

Regarding the above polyvinyl chloride resin composition,
The following performance evaluation was performed, and the results are shown in Table 3. (I) Thermal stability The polyvinyl chloride resin composition was kneaded with a 180 ° C mixing roll for 5 minutes to prepare a sheet having a thickness of 1 to 2 mm. It was left in the oven for a predetermined period of time, and the coloring state was visually observed.
The coloring of the sheet-like material changes from ocher color of wood powder to light brown → brown → black with heat deterioration when left to stand at high temperature, but the coloring during 30 minutes is not enough heat until molding until light brown. It was judged that the stability was sufficient.

(II) Extrudability The above polyvinyl chloride resin composition was applied to a single-screw extruder having the following specifications ("GT-32-A" manufactured by Plastic Engineering Laboratory Co., Ltd.).
It was supplied to a mold and molded under the following molding conditions to obtain a flat plate-shaped molded body. [Extruder specifications] 1) Cylinder: diameter 300 mm 2) Screw: L / D = 28 3) Mold: T die, lip: width 150 x thickness 2 mm [Molding conditions] 1) Molding temperature: C ₁ = 150 ° C , C ₂ = 170 ° C., C ₃
= 175 ° C., C ₄ = 180 ° C., AD = 180 ° C., D = 1
It was set at 75 ° C. The "clogged" condition during the above-mentioned molding and the surface condition of the obtained molded product were judged according to the following criteria. ◯: Smooth feel and gloss. Δ: The texture is not smooth and is rough. X: Unevenness is recognized with the naked eye.

[0037]

[Table 3]

In the thermal stability evaluation, it was confirmed that both Comparative Examples 1 and 2 turned black within 30 minutes, and rapid thermal deterioration occurred. Further, in the evaluation of extrusion moldability, in both Comparative Examples 1 and 2, “clog” was generated in the molding machine, discharge was stopped, and when the mold was disassembled, the resin composition became dark brown or black, and due to aggregation of the wood powder. Granules having a diameter of 1 to 2 mm were observed.

[Preparation of Preliminary Mixture of Wood Powder] The predetermined amounts of wood powder (b), lead compound (d) and plasticizer shown in Table 4 were put into a super mixer (20 liters, manufactured by Kawata Industry Co., Ltd.). The mixture was mixed at 40 to 80 ° C. for 1 hour for pretreatment. The following compounds were used as the lead compound (d) and the plasticizer.・ Lead compound (d): tribasic lead sulfate (“TL manufactured by Sakai Chemical Co., Ltd.”
# 7000 ").・ Plasticizer: Dioctyl phthalate (DOP)

[0040]

[Table 4]

(Examples 8 to 6, Comparative Examples 1 and 2) A predetermined amount of polyvinyl chloride resin (a), wood powder (b) (preliminary mixture), metal soap (c) and The stabilizing aid was put in a super mixer and mixed at 70 to 120 ° C. for 15 minutes to prepare a polyvinyl chloride resin composition.

[0042]

[Table 5]

Regarding the above polyvinyl chloride resin composition,
The same performance evaluation as in Example 1 was performed, and the results are shown in Table 6.

[0044]

[Table 6]

[0045]

The method for producing the vinyl chloride resin composition of the present invention is as described above, and since the surface of the wood powder is coated with the metallic soap and / or the lead compound, the generation of the wood powder occurs. The acidic gas generated is suppressed, the agglomeration of the wood powder is prevented, and the slidability is maintained, so that stable extrusion molding is possible.

Claims (1)

[Claims] 1. When producing a polyvinyl chloride resin composition comprising (a) 100 parts by weight of polyvinyl chloride resin and (b) 5 to 80 parts by weight of wood powder, (b) wood powder 10
0.5 parts by weight or more of (c) metal soap and / or (d) lead-based compound based on 0 parts by weight, and (a) metal soap or (c) based on 100 parts by weight of polyvinyl chloride resin. as well as/
Alternatively, (d) the lead-based compound is added in a proportion of 20 parts by weight or less, and (b) the wood powder and (c) the metal soap and / or (d) the lead-based compound are premixed in advance. A method for producing a polyvinyl chloride resin composition.