JP3107668B2 - Extrusion molding resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

[0003] In particular, for applications requiring impact resistance and weather resistance, a vinyl chloride composition comprising a mixture of a vinyl chloride resin, an acrylic rubber-based reinforcing agent and an acrylic rubber-based processing aid (JP-A-60-161449). Publication). However, there is a problem that the above composition has poor extrusion moldability and non-uniform fluidity, so that a molded article having a predetermined shape cannot be obtained.

On the other hand, in order to improve moldability,
A polymer obtained by graft-polymerizing vinyl chloride to a partially crosslinked alkyl (meth) acrylate polymer is used. Although the above-mentioned 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 of the present invention is to obtain a molded article having excellent moldability, excellent impact resistance and excellent mechanical strength. And 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 having a homopolymer having a secondary transition point of -20 ° C. or less, and has a crosslink rate of 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 secondary transition point of -20 ° C. or lower. For example, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl Examples thereof include acrylate, n-octyl methacrylate, n-decyl methacrylate, and n-dodecyl methacrylate, and one or more of these are used.

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

Other monomers polymerizable with the alkyl (meth) acrylate include, for example, styrene, α-
Styrene monomers of methylstyrene; acrylonitrile; alkyl (meth) acrylate monomers having a secondary transition point of higher than −20 ° C .;

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

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

Regardless of whether the crosslinking ratio of the above alkyl (meth) acrylate polymer is small or large, the impact strength of the molded article becomes insufficient, so that the crosslinking ratio is limited to 50 to 95% by weight.

[0013] The above-mentioned cross-linking ratio is based on 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 above-mentioned alkyl (meth) acrylate polymer, it is preferable to react a polyfunctional monomer. 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 maleate.

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

The additives used in the above emulsion polymerization are not particularly limited, and examples thereof include a dispersion emulsifier, a polymerization initiator and the like.

Examples of the dispersion emulsifier include anionic surfactants, nonionic surfactants, partially saponified polyvinyl alcohol, cellulose dispersants, and gelatin. Examples of the polymerization initiator include persulfate. Water-soluble initiators such as potassium, ammonium sulfate and hydrogen peroxide; and oil-soluble initiators such as benzoyl peroxide and lauroyl peroxide.

At the time of the above emulsion polymerization, a pH adjuster, an antioxidant and the like may be further added as necessary.

The graft polymer used in the present invention is a polymer obtained by graft-polymerizing a vinyl chloride monomer on the above-mentioned alkyl (meth) acrylate polymer.

In general, the vinyl chloride homopolymer used for extrusion molding has a viscosity average degree of polymerization of 600 to 1400.
Are preferred. Therefore, when graft-polymerizing vinyl chloride in the present invention, the viscosity-average polymerization degree is 600 to 1400 by a viscosity-average polymerization method using a calibration curve of the viscosity-average polymerization degree prepared from a vinyl chloride homopolymer. It is preferable to carry out polymerization under suitable conditions.

The above graft polymer may be copolymerized with vinyl chloride and a monomer other than vinyl chloride as long as the properties 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; Vinylidene, etc., 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 is small, the impact strength of the obtained molded article becomes insufficient, and when the amount is large, the elastic modulus of the obtained molded article is reduced. Therefore, the alkyl (meth) acrylate polymer is 4 to 30% by weight. Limited to, preferably 6
-20% by weight.

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

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

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

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

[0028]

Embedded image In the formula, R ¹ and R ² are 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 when the number of carbon atoms is large, it is difficult to obtain.

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 the carbon number is large, the lubricity becomes too strong and the physical properties of the molded article are impaired. ~ 27.

In the resin composition of the present invention, when the amount of the organotin compound is small, the effect of improving the fluidity is not obtained, and when the amount is large, the lubricity of the plate becomes strong and the impact resistance becomes insufficient. It is limited to 0.2 to 3 parts by weight based on 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 stabilizer, barium-zinc stabilizer, barium-cadmium stabilizer, epoxidized soybean oil, phosphate esters, etc. Stabilizing aid; paraffin wax, polyethylene wax,
Lubricants such as stearyl alcohol stearate and butyl stearate; acrylic processing aids having a weight average molecular weight of less than 1,000,000; antioxidants; ultraviolet absorbers; light stabilizers; fillers such as calcium carbonate and talc; titanium oxide and 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 in order to improve the processability of the molded article.

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

[0035]

Next, an embodiment of the present invention will be described. (Examples 1 to 5, Comparative Examples 1 to 8) 100 parts by weight of a vinyl chloride graft polymer having the composition shown in Table 1 were added with a predetermined amount of an organotin compound shown in Table 1 and dibutyltin maleate as an additive. Polymer (“BM (N)” manufactured by Sankyoki Gosei Co., Ltd.)
5 parts by weight, 2.5 parts by weight of dibutyltin mercapto (“JF-10B” manufactured by Sankyoki 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")
0.5 part by weight, 0.5 part by weight of calcium stearate (“SC-100” manufactured by Sakai Chemical Co., Ltd.), and 1 part by weight of an acrylic processing aid (“METABLEN P-501” manufactured by Mitsubishi Rayon Co., Ltd.) are added and mixed with a mixer. The mixture was uniformly mixed, and a molded body 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 measurement was carried out on the test piece taken from the above molded product, and the results are shown in Table 1. (1) Moldability A molded body having the cross-sectional shape shown in FIG. 1 was molded, and the ratio (A / B) of the extrusion speeds of the portions A and B was measured. It was judged to be excellent. (2) Izod impact strength Measured according to JIS K7110. (3) Flexural modulus Measured according to JIS K7203.

[0037]

[Table 1]

[0038]

As described above, the resin composition for extrusion molding of the present invention is excellent in moldability, impact resistance, and mechanical strength, and therefore, is used in building material parts, vehicle parts, and audio / communication equipment. And OA equipment and the like.

[Brief description of the drawings]

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

Claims (1)

(57) [Claims] An alkyl (meth) acrylate monomer mainly comprising an alkyl (meth) acrylate monomer having a secondary transition point of -20 ° C. or lower and a crosslink rate of 50 to 95% by weight.
100 to 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% by weight of an organotin compound represented by the general formula (I) A resin composition for extrusion molding, comprising: Embedded image (Wherein, R ¹ and R ² are an alkyl group having 4 to 8 carbon atoms,
R ³ and R ⁴ each represent an alkyl group having 16 to 27 carbon atoms. )