JPH06157862A - Extrusion molding resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. excellent in impact strength, weatherability. extrudability, and mechanical strengths by compounding a specific graft polymer with a specific organotin compd. in a specified wt. ratio. CONSTITUTION:This resin compsn. is obtd. by compounding 0.2-3 pts.wt. organotin compd. of the formula (wherin R<1> and R<2> are each 4-8C alkyl; and R<3> and R<4> are each 16-17C alkyl) into 100 pts.wt. graft polymer obtd. by grafting 96-70wt.% vinyl chloride onto 4-30wt.% alkyl (meth)acrylate polymer which has a degree of crosslinking of 50-95wt.% and is produced from a monomer component mainly comprising an alkyl (meth)acrylate whose homopolymer has a glass transition point of -20 deg.C or lower (e.g. m-butyl acrylate).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion molding resin composition having excellent impact resistance, weather resistance and extrusion moldability.

[0002]

2. Description of the Related Art Vinyl chloride resins are used in a wide range of applications because they have many excellent characteristics such as impact resistance, weather resistance and water resistance.

Particularly, for applications requiring impact resistance and weather resistance, a vinyl chloride composition containing a vinyl chloride resin, an acrylic rubber-based reinforcing agent and an acrylic rubber-based processing aid mixed therein (Japanese Patent Laid-Open No. 60-161449). Issue). However, the above-mentioned composition has a problem that a molded article having a predetermined shape cannot be obtained because the extrusion moldability is poor and the fluidity becomes nonuniform.

On the other hand, in order to improve the moldability,
A polymer obtained by graft-polymerizing vinyl chloride on a partially crosslinked alkyl (meth) acrylate polymer is used. Since the above polymer can be molded with low viscosity, the moldability is slightly improved, but there is a problem that uniform fluidity cannot be obtained.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to obtain a molded article having excellent moldability, impact resistance and mechanical strength. The present invention relates to a resin composition for extrusion molding.

[0006]

The alkyl (meth) acrylate polymer used in the present invention is mainly composed of an alkyl (meth) acrylate monomer whose homopolymer has a second-order transition point of -20 ° C or lower, and has a crosslinking rate. It is a polymer of 50 to 95% by weight.

The alkyl (meth) acrylate monomer is not particularly limited as long as it has a second-order transition point of -20 ° C. or lower. For example, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl. Acrylate, n-octyl methacrylate, n-decyl methacrylate, n-dodecyl methacrylate and the like can be mentioned, and one or more of these can be used.

In the present invention, if necessary, the alkyl (meth) acrylate may be used in combination with another monomer which is polymerizable with the alkyl (meth) acrylate.

Other monomers polymerizable with the above alkyl (meth) acrylate include, for example, styrene and α-
Examples thereof include a styrene-based monomer of methylstyrene; acrylonitrile; and an alkyl (meth) acrylate monomer having a second-order transition point of higher than -20 ° C.

Examples of the alkyl (meth) acrylate monomer having a second-order transition point exceeding -20 ° C include, for example, methyl acrylate, methyl methacrylate, isopropyl acrylate, n-butyl methacrylate, t-butyl acrylate, n-hexyl methacrylate and n. -Alkyl acrylates such as tetradecyl (meth) acrylate, n-hexadecyl acrylate, lauryl acrylate and cyclohexyl acrylate are mentioned, and one or more of these monomers are used.

The amount of the other monomer in the alkyl (meth) acrylate polymer is preferably 10% by weight or less, since the impact resistance decreases as the amount increases.

Even if the cross-linking ratio of the above-mentioned alkyl (meth) acrylate polymer is small or large, the impact strength of the molded product becomes insufficient, so that the cross-linking ratio is limited to 50 to 95% by weight.

The above-mentioned cross-linking ratio is a certain amount of alkyl (meth)
It is determined by dissolving the acrylate polymer in THF at 30 ° C. and measuring the weight ratio of the insoluble portion.

In order to crosslink the alkyl (meth) acrylate polymer, it is preferable to react a polyfunctional monomer, and examples of such a polyfunctional monomer include ethylene glycol diacrylate, diethylene glycol diacrylate and triethylene glycol. Examples thereof include diacrylate, ethylene glycol dimethacrylate, diallyl phthalate and diallyl malate.

In the present invention, the method for obtaining the crosslinked alkyl (meth) acrylate polymer is not particularly limited, and examples thereof include emulsion polymerization method and suspension polymerization method. Is preferred.

The additive used in the emulsion polymerization is not particularly limited, and examples thereof include a dispersion emulsifier and a polymerization initiator.

Examples of the dispersant emulsifier include anionic surfactants, nonionic surfactants, partially saponified polyvinyl alcohol, cellulosic dispersants, gelatin, and the like. Polymerization initiators include, for example, persulfuric acid. Examples thereof include water-soluble initiators such as potassium, ammonium sulfate and hydrogen peroxide; oil-soluble initiators such as benzoyl peroxide and lauroyl peroxide.

At the time of the emulsion polymerization, a pH adjusting agent, an antioxidant and the like may be added, if necessary.

The graft polymer used in the present invention is a polymer in which a vinyl chloride monomer is graft-polymerized to the above-mentioned alkyl (meth) acrylate polymer.

Generally, the vinyl chloride homopolymer used in extrusion molding has a viscosity average degree of polymerization of 600 to 1400.
Are preferred. Therefore, in the present invention, when the vinyl chloride is graft-polymerized, the viscosity average polymerization degree is 600 to 1400 by the viscosity average polymerization method using the calibration curve of the viscosity average polymerization degree prepared from the vinyl chloride homopolymer. It is preferable to polymerize under various conditions.

The above graft polymer may be copolymerized with vinyl chloride and a monomer other than vinyl chloride, as long as the characteristics of vinyl chloride are not impaired. Examples of such a monomer include α-olefins such as ethylene and propylene; vinyl esters such as vinyl acetate and vinyl stearate; N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide; Examples thereof include vinylidene, and one or more of these are used.

In the above graft polymer, the amount of monomers other than vinyl chloride is preferably 20% by weight or less.

Alkyl (meth) in the above graft polymer
When the amount of the acrylate polymer decreases, the impact strength of the obtained molded product becomes insufficient, and when the amount of the acrylate polymer increases, the elastic modulus of the obtained molded product lowers. Limited to, preferably 6
Is about 20% by weight.

As the polymerization method for graft-polymerizing vinyl chloride onto the above alkyl (meth) acrylate polymer, for example, emulsion polymerization method, suspension polymerization method, solution polymerization method and the like can be used. Among them, the suspension polymerization method is used. Is preferred.

In the above suspension polymerization method, as a dispersion emulsifier,
Examples include anionic surfactants, nonionic surfactants, partially saponified polyvinyl alcohol, and cellulose-based dispersants. Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, and 2
-Peroxides such as ethylhexyl peroxydicarbonate; 2,2-azobisisobutyronitrile,
Examples thereof include azo compounds such as 2,2-azobis-2,4-dimethylvaleronitrile.

In the above suspension polymerization method, a pH adjusting agent, a polymerization degree adjusting agent, an antioxidant and the like may be added, if necessary.

The organotin compound used in the present invention is represented by the general formula (I).

[0028]

[Chemical 2] In the formula, R ¹ and R ² are each an alkyl group having 4 to 8 carbon atoms, R ³ ,
R ⁴ represents an alkyl group having 16 to 27 carbon atoms.

When the number of carbon atoms of the alkyl group represented by R ¹ and R ² is small, there is no effect of improving fluidity, and it is difficult to obtain a large one, so the number of carbon atoms is limited to 4 to 8.

When the carbon number of the alkyl group represented by R ³ and R ⁴ is small, there is no effect of improving the fluidity, and when it is large, the slipperiness becomes too strong and the physical properties of the molded article are impaired. Limited to ~ 27.

In the resin composition of the present invention, if the amount of the above-mentioned organotin compound is small, there is no effect of improving the fluidity, and if it is too large, the slipperiness of the plate becomes strong and the impact strength becomes insufficient. It is limited to 0.2 to 3 parts by weight with respect to 100 parts by weight of the graft polymer.

In the resin composition of the present invention, if necessary,
Organic tin stabilizers such as dibutyltin mercapto, dioctyltin mercapto, dimethyltin mercapto, dibutyltin malate, dibutyltin malate polymer, dioctyltin malate, dioctyltin malate polymer, dibutyltin laurate; tribasic lead sulfate, dibasic Lead stabilizers such as lead phosphite and lead stearate; heat stabilizers such as calcium-zinc stabilizers, barium-zinc stabilizers, barium-cadmium stabilizers, epoxidized soybean oil, phosphate esters, etc. Stabilizing aids; paraffin wax, polyethylene wax,
Lubricants such as stearyl stearate and butyl stearate; Acrylic processing aids having a weight average molecular weight of less than 1,000,000; Antioxidants; UV absorbers; Light stabilizers; Fillers such as calcium carbonate and talc; Titanium oxide, carbon A pigment such as black may be added.

Further, a small amount of a plasticizer such as di-2-ethylhexyl phthalate, dibutyl phthalate or di-2-ethylhexyl adipate may be added to improve the processability of the molded product.

As a method for mixing the resin composition of the present invention, any method such as a hot blending method and a cold blending method may be used. If necessary, pelletization may be performed.

[0035]

Embodiments of the present invention will be described below. (Examples 1 to 5 and Comparative Examples 1 to 8) 100 parts by weight of a vinyl chloride graft polymer having the composition shown in Table 1 was added with a predetermined amount of the organotin compound shown in Table 1 and dibutyltin malate as an additive. Polymer (“BM (N)” manufactured by Sankyo Machine Gosei Co., Ltd.) 0.
5 parts by weight, 2.5 parts by weight of dibutyltin mercapto (“JF-10B” manufactured by Sankyo Machine Gosei Co., Ltd.), 1.5 parts by weight of stearic acid (“F-3” manufactured by Kawaken Fine Chemical Co., Ltd.), polyethylene wax (Mitsui Petrochemical "4202E")
Add 0.5 parts by weight, 0.5 parts by weight of calcium stearate ("SC-100" manufactured by Sakai Chemical Industry Co., Ltd.), and 1 part by weight of acrylic processing aid ("Metablene P-501" manufactured by Mitsubishi Rayon Co., Ltd.) with a mixer. The mixture was uniformly mixed, and a 50 mm different-direction biaxial extruder was used to extrude a molded product having the shape shown in FIG.
At this time, the resin temperature is 190 ° C and the extrusion rate is about 50 kg / hr.
Met.

The following measurements were carried out on the test pieces collected from the above-mentioned molded product, and the results are shown in Table 1. (1) Moldability A molded article having the cross-sectional shape shown in FIG. 1 is molded, and the ratio (A / B) of the extrusion speeds of the A part and the B part is measured. It was judged to be excellent. (2) Izod impact strength It was measured according to JIS K7110. (3) Bending elastic modulus It was measured according to JIS K7203.

[0037]

[Table 1]

[0038]

The resin composition for extrusion molding of the present invention is as described above, and is excellent in moldability, impact resistance and mechanical strength, so that it is a building material part, a vehicle part, an audio / communication device. It is preferably used for housings of OA equipment and the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a molded body used for evaluation of moldability in Examples and Comparative Examples.

Claims (1)

[Claims] 1. An alkyl (meth) which is mainly composed of an alkyl (meth) acrylate monomer having a homopolymer having a second-order transition temperature of -20 ° C. or lower and a crosslinking rate of 50 to 95% by weight.
100 parts by weight of a graft polymer in which 96 to 70% by weight of a vinyl chloride monomer is graft-polymerized to 4 to 30% by weight of an acrylate polymer, and 0.2 to 3 parts by weight of an organotin compound represented by the general formula (I). And a resin composition for extrusion molding. [Chemical 1] (In the formula, R ¹ and R ² are alkyl groups having 4 to 8 carbon atoms,
R ³ and R ⁴ each represent an alkyl group having 16 to 27 carbon atoms. )