JPH06192534A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a composition composed of a thermoplastic resin and a specific impact modifier at a specific ratio, having excellent impact resistance and exhibiting good moldability and weather resistance. CONSTITUTION:The composition is composed of (A) 100 pts.wt. of a thermoplastic resin and (B) 3-50 pts.wt. of an impact modifier produced by compounding (i) 100 pts.wt. of a graft copolymer containing 0.1-5wt.% of a polyfunctional crosslinking agent (e.g. triallyl cyanurate) and produced by the graft- copolymerization of an acrylic elastomer with a monomer or monomer mixture composed of 95-100wt.% of a monomer consisting of alkyl methacrylate, aromatic vinyl compound and vinyl cyanide compound and 0-5wt.% of a polyfunctional crosslinking agent with (ii) 0.1-20 pts.wt. of a copolymer composed of 3-30wt.% of an unsaturated acid monomer and 97-70wt.% of a vinyl monomer. The copolymer of the acrylic elastomer, unsaturated acid monomer and vinyl monomer is preferably produced by emulsion polymerization method.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Thermoplastic resins, particularly vinyl chloride resins (hereinafter abbreviated as PVC) are widely used as general-purpose resins, but their mechanical properties are not always satisfactory. That is, PVC is inferior in impact strength, particularly impact strength with a notch, and various modifiers have been proposed for the purpose of improving such impact strength.

The most effective method among these proposals is so-called MBS resin in which a conjugated diene elastic body is graft-polymerized with a methacrylic acid alkyl ester and an aromatic vinyl compound, and a conjugated diene elastic body is graft-polymerized with a vinyl cyan compound and an aromatic vinyl compound. It is known to blend the ABS resin with PVC. However, since these MBS resins and ABS resins contain many double bonds in the main chain of the elastic body component, when used outdoors for a long time, they tend to cause a choking phenomenon, a drop in impact strength, etc. and are not suitable for outdoor applications. .

Also proposed is a method of using an elastic body in which a saturated alkyl acrylate is partially replaced by a conjugated diene. In this case, although a high impact strength improving effect is exhibited, it has a drawback that the weather resistance is not so good as that of the MBS resin or the ABS resin.

Further, a resin composition having a good weather resistance is prepared by blending a copolymer obtained by graft-polymerizing a methacrylic acid alkyl ester, an aromatic vinyl compound, a vinyl cyan compound, etc., with a saturated polyacrylic acid alkyl ester as an elastic body with PVC. Have also been proposed.

However, these copolymers show a considerable effect of improving the impact strength, even though they are not as good as the MBS resin under the condition that they are well kneaded, but when a large amount of lubricant is used, or they are processed at a relatively low temperature. In the case of no kneading, such as in the case of crushing, almost no effect of improving impact strength is exhibited.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention uniformly disperse a graft copolymer obtained by graft-polymerizing a resin-forming monomer on an acrylic elastic body containing alkyl acrylate as a main component in PVC. We paid attention to that it greatly contributes to the impact strength development. As a result, it was found that the resin composition obtained by blending PVC, which is a well-known graft copolymer having the above acrylic elastomer as a component, with PVC has a very poor dispersion state under molding conditions in which gelation is slow and shear stress is low. did.

The present inventors have made the above graft copolymer a PV
As a result of intensive studies on promoting gelation in order to disperse well in C, surprisingly, the above-mentioned graft copolymer, which is well known in the art, and an unsaturated acid monomer as essential constituents When the impact modifier containing a specific copolymer is blended with PVC in a specific range and is molded and molded, gelation is very fast even under conditions where the shear stress at the time of molding is low and kneading is difficult. It is needless to say that it is dispersed and gives high impact strength, and further gives high impact strength under conditions where it is well kneaded, and gives high impact resistance to PVC under a wide range of molding conditions, Moreover, they have found that they have improved workability and surface gloss and are also excellent in weather resistance, and have reached the present invention.

[0009]

The present invention provides a thermoplastic resin 1
Acrylic elastomer containing acrylic acid alkyl ester as a main component, containing 100 parts by weight and 0.1 to 5% by weight of a polyfunctional crosslinking agent, and a methacrylic acid alkyl ester, an aromatic vinyl compound, and a vinyl cyan compound. 95-100% by weight of at least one monomer selected from the group of monomers
And 100% by weight of a graft copolymer (A) obtained by graft-polymerizing a monomer or monomer mixture consisting of 0 to 5% by weight of a polyfunctional crosslinking agent in one stage or in multiple stages, and a unsaturated acid monomer 3 to 30% by weight and vinyl monomer 9 copolymerizable therewith
Copolymer (B) obtained by copolymerizing 7 to 70% by weight
Weather resistance, impact resistance consisting of 3 to 50 parts by weight of impact resistance modifier having good weather resistance of 0.1 to 20 parts by weight.
And a thermoplastic resin composition having good moldability.

The alkyl acrylate used as a component of the acrylic elastomer which is a constituent of the graft copolymer (A) in the present invention has an alkyl group having 2 to 10 carbon atoms, and its specific Examples include ethyl acrylate, propyl acrylate, acrylic acid n-
Butyl, isobutyl acrylate, hexyl acrylate,
Examples include n-octyl acrylate and 2-ethylhexyl acrylate. Further, other copolymerizable vinyl monomers can be copolymerized with the acrylic elastic body within a range in which elasticity is not lost.

It is necessary that the acrylic elastic body contains a polyfunctional cross-linking agent that facilitates the graft cross-linking, and the amount thereof is 0.1 to the acrylic elastic body.
~ 5% by weight. If it is less than 0.1% by weight, sufficient graft crosslinkage cannot be obtained, and if it exceeds 5% by weight, elastic properties are impaired, which is not preferable. Specific examples of the polyfunctional crosslinking agent, divinylbenzene, those having a diacrylic acid ester or dimethacrylic acid ester or an allyl group which is an ester of acrylic acid or methacrylic acid and a polyhydric alcohol, such as triallyl cyanurate, triallyl isocyanurate, Examples thereof include allyl acrylate, allyl methacrylate, diallyl itaconic acid, diallyl phthalate and the like. An allyl group-containing crosslinking agent is particularly preferable from the viewpoint of graft crossing property.

The acrylic elastic body is preferably produced by a usual emulsion polymerization method.

Examples of emulsifiers include anionic surfactants such as fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, alkyl phosphate ester salts, dialkyl sulfosuccinates, polyoxyethylene alkyl ethers, and polyoxyethylene. Nonionic surfactants such as fatty acid esters, sorbitan fatty acid esters and glycerin fatty acid esters, and cationic surfactants such as alkylamine salts can be used. These surfactants can be used alone or in combination. Further, depending on the kind of the emulsifier, when the pH of the polymerization system is on the alkaline side, an appropriate pH adjusting agent can be used in order to prevent the hydrolysis of the alkyl acrylate.

As the polymerization initiator, an ordinary inorganic initiator such as persulfate, an organic peroxide, an azo compound or the like may be used alone, or the above compound and a sulfite, a hydrogen sulfite or a thiosulfate may be used. , A first metal salt, sodium formaldehyde sulfoxylate, etc. can be used in combination as a redox initiator. Preferred persulfates as initiators are sodium persulfate, potassium persulfate,
Examples of organic peroxides include ammonium persulfate and the like.
Examples thereof include t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide and the like.

A chain transfer agent may be used to control the molecular weight of the polymer, and an alkylmercaptan having 5 to 20 carbon atoms can be used.

The polymerization can be carried out at a temperature equal to or higher than the decomposition temperature of the polymerization initiator under ordinary emulsion polymerization conditions. The polymerization can be carried out at once with the whole amount of the monomer or the mixture of the monomers, or while continuously adding the whole amount or a part thereof.
However, from the viewpoints of stability of polymerization, removal of heat of polymerization reaction, etc., it is preferable to carry out the polymerization while adding the whole amount or a part thereof.

The graft copolymer (A) in the present invention is added in an amount of 25 to 1 in the presence of 100 parts by weight of the acrylic elastomer.
It is preferably obtained by graft-polymerizing 25 parts by weight of a monomer or a mixture of monomers. If the amount of the monomer or monomer mixture to be graft-polymerized is less than 25 parts by weight, the moldability of the resin composition when blended with PVC is extremely poor and the impact strength tends to be low, which is not preferable. If it exceeds 125 parts by weight, PV
When blended with C, the impact resistance improving effect is small.

As the monomer to be grafted, at least one kind of monomer selected from the group of monomers consisting of methacrylic acid alkyl ester, aromatic vinyl compound and vinyl cyan compound can be used, each of which may be used alone or It is possible to mix and carry out graft polymerization in one step or in multiple steps.

As the methacrylic acid alkyl ester,
An alkyl group having 1 to 4 carbon atoms is preferable, and examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and tert-butyl methacrylate. To be Considering the compatibility with PVC, methyl methacrylate is preferable.

Examples of the aromatic vinyl compound include, in addition to styrene, α-substituted styrene, nucleus-substituted styrene and derivatives thereof, such as α-methylstyrene, chlorostyrene and vinyltoluene.

Further, examples of the vinyl cyan compound include acrylonitrile and methacrylonitrile.

Graft polymerization may be carried out following the production of the acrylic elastic body or under a normal emulsion polymerization condition in a separate reactor, if necessary, with an initiator, a polymerization degree modifier, a polyfunctional crosslinking agent and the like. It can be added. As the initiator, the chain transfer agent, and the polyfunctional crosslinking agent, those described for the acrylic elastic body can be used. In the case of graft polymerization, a monomer or monomer comprising 95 to 100% by weight of at least one monomer selected from the group of monomers to be grafted and 0 to 5% by weight of a polyfunctional crosslinking agent. The mixture is obtained by one-step or multi-step graft polymerization. Further, in this graft polymerization, the total amount of each monomer can be continuously or discontinuously added at one stage to proceed the polymerization.

The copolymer (B) in the present invention is obtained by copolymerizing 3 to 30% by weight of an unsaturated acid monomer and 97 to 70% by weight of a vinyl monomer copolymerizable therewith. The emulsion polymerization method is preferable as the production method.

The unsaturated acid monomer is an acid group-containing monomer such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, cinnamic acid, maleic anhydride or butenetricarboxylic acid. The amount of unsaturated acid monomer in the copolymer (B) is 3% by weight.
If the amount is less than the above range, the impact resistance improving effect is not preferable because it is blended with the graft copolymer (A) and used as an impact resistance modifier. If it exceeds 30% by weight, the latex obtained by emulsion polymerization is not stable, and when blended with the latex of the graft copolymer (A), the latex stability is deteriorated or the processability is deteriorated. It is not preferable because it may happen.

Examples of vinyl monomers copolymerizable with unsaturated acid monomers include acrylic acid alkyl esters, methacrylic acid alkyl esters, aromatic vinyl compounds, and the like.
These can be used alone or as a mixture thereof.

When the copolymer (B) is produced by an emulsion polymerization method, the same emulsifier, polymerization initiator, chain transfer agent, etc. which can be used in the production of the graft copolymer (A) are used. It is possible to carry out copolymerization in the same manner as in the production of the graft copolymer (A).

The impact modifier of the present invention is a blend of the graft copolymer (A) and the copolymer (B) obtained as described above, and the blending ratio thereof is 1 for the graft copolymer (A).
The copolymer (B) is 0.1 to 20 parts by weight with respect to 00 parts by weight. If the blending amount of the copolymer (B) is less than 0.1 part by weight, the impact resistance improving effect is small, and if the blending amount exceeds 20 parts by weight, a copolymer mixture obtained by latex blending both copolymers is good. It is not preferable because it cannot be obtained as powder.

In carrying out the present invention, the graft copolymer (A) and the copolymer (B) are blended by mixing the respective latexes in the above-mentioned mixing ratio in terms of solid content, and the blended latex is usually salted out. Alternatively, it may be collected by powdering after acidification and coagulation, washing with filtered water, or by spray drying or freeze drying. Furthermore, JP-A-5
It can also be recovered by the method described in JP-A-7-187322.

By blending the impact modifier of the present invention with various thermoplastic resins, it imparts high impact properties and good processability to the thermoplastic resin, and the molded product also has good weather resistance. It is what

The proportion of the impact modifier of the present invention incorporated into the thermoplastic resin is 3 to 100 parts by weight of the thermoplastic resin.
It is 50 parts by weight. If it is less than 3 parts by weight, the impact resistance improving effect is small, and if it exceeds 50 parts by weight, the mechanical properties originally possessed by the thermoplastic resin are impaired, which is not preferable. Here, the thermoplastic resin is PV
C, a polycarbonate resin, a polyester resin, an acrylonitrile-styrene-based resin, a methyl methacrylate-styrene-based resin, and the like. As PVC, in addition to polyvinyl chloride, a vinyl chloride-based copolymer containing 70% by weight or more of vinyl chloride can be used. Monomers copolymerizable with vinyl chloride include ethylene, propylene, vinyl bromide,
Vinylidene chloride, vinyl acetate, acrylic acid ester, methacrylic acid ester and the like are used.

The impact modifier of the present invention and the thermoplastic resin are preferably mixed in a powder form, for example, by a ribbon blender, a Henschel mixer or the like, and a known kneading machine,
For example, it is molded by a mixing roll, a Banbury mixer, an extruder, an injection molding machine and the like. When blending, known stabilizers, plasticizers, lubricants, colorants and the like may be added as necessary.

[0032]

The present invention will be described in detail with reference to the following examples. In the examples, "part" and "%" are "part by weight",
It means "% by weight".

Example 1 (1) Production of Graft Copolymer (A) 180 parts of nitrogen-exchanged deionized water was placed in a reaction vessel,
0.3 parts of boric acid, 0.03 parts of anhydrous sodium carbonate, 1.5 parts of potassium oleate and 0.15 parts of potassium persulfate are dissolved,
A mixture of 99.5 parts of n-butyl acrylate and 0.5 part of allyl methacrylate was added dropwise over 4 hours while stirring at 70 ° C. After completion of the dropping, the temperature was maintained for 2 hours while maintaining the same temperature to complete the polymerization. The polymerization rate was 99.2%, and the system pH was 7.2.

Obtained acrylic elastic latex 10
0 parts (as solid content), 100 parts of ion-exchanged water, 0.2 parts of sodium formaldehyde sulfoxylate and 0.3 parts of potassium oleate were charged into a reaction vessel, and methyl methacrylate 50 was added while stirring at 70 ° C. Part, styrene 10 parts, acrylonitrile 5 parts, allyl methacrylate 0.25 parts and cumene hydroperoxide 0.2 parts were added dropwise over 2 hours. After the dropping was completed, the temperature was kept at the same temperature for 2 hours to complete the polymerization, and a graft copolymer (A) latex was obtained. The polymerization rate in the graft copolymerization was 99% or more for each monomer, and the average particle size of the obtained graft copolymer was 0.23 μm.

(2) Manufacture of copolymer (B) 200 parts of ion-exchanged water which had been purged with nitrogen was put in a reaction vessel,
Dissolve 3 parts of semi-hardened tallow fatty acid soap and 0.6 part of potassium persulfate, 45 parts of ethyl acrylate, 4 parts of methyl methacrylate
A mixture of 5 parts and 10 parts of methacrylic acid was added at a temperature of 70.
While maintaining the temperature at 0 ° C., the mixture was added dropwise over 4 hours, maintained for 3 hours and polymerized to obtain a copolymer (B) latex. The polymerization rate was 99.9% or more.

(3) Latex Blend and Polymer Recovery 100 parts (as solid content) of the graft copolymer (A) latex was placed in a reaction kettle equipped with a stirrer to obtain the copolymer (B).
2 parts of latex (as solid content) was added with stirring for 10 seconds and stirred for 5 minutes.

The latex mixture thus obtained was added to an aqueous sulfuric acid solution, acidified and coagulated, washed, dehydrated and dried to recover a polymer in powder form (Example 1-1)).

Table 1 also shows various changes in the addition amount of the copolymer (B).

(4) Production of compounded composition with vinyl chloride resin 100 parts of vinyl chloride resin having an average degree of polymerization of 1100, 1.0 part of tribasic lead sulfate, 0.3 part of dibasic stearic acid, lead stearate 2.4 parts, 0.3 parts of stearic acid, 0.3 parts of polyethylene wax, 13 parts of each modifier obtained in the above (3) were added, and 11 parts were added in a Henschel mixer.
The temperature was raised to 5 ° C. to obtain a uniform mixture. This vinyl chloride resin composition was molded into a square rod under the following conditions with a 30 mm single screw extruder.

Cylinder 1 150 ° C. Cylinder 2 165 ° C. Cylinder 3 180 ° C. Die 200 ° C. Screw CR = 3.0, 30 mmφ full flight screw The impact strength of the molded product is the same except that a specimen with a 2 mm deep U-notch is used. It was measured according to ASTM D-256.

The results of these measurements are shown in Table 1.

[0042]

[Table 1]

From the above results, it is understood that the impact resistance improving effect is improved by blending the copolymer (B) in a specific amount.

Example 2 As a copolymer (B), a mixture of 50 parts of n-butyl acrylate, 35 parts of methyl methacrylate and 15 parts of acrylic acid was polymerized in the same manner as in (2) of Example 1. A copolymer (B) latex was obtained.

3 parts (as solid content) of this copolymer (B) latex were blended with 100 parts (as solid content) of the graft copolymer (A) latex obtained in (1) of Example 1 and carried out. Table 2 shows the results obtained by measuring the impact resistance of the vinyl chloride resin composition obtained by the same operation as in (3) and (4) of Example 1 by the same evaluation method. Table 2 also shows the evaluation results of the copolymer (B) whose composition and addition amount were changed.

[0046]

[Table 2]

The abbreviations in Table 2 are as follows, and the same applies to the subsequent cases.

BA: n-butyl acrylate MAA: methacrylic acid MMA: methyl methacrylate IA: itaconic acid AA: acrylic acid St: styrene EA: ethyl acrylate CA: crotonic acid MA: methyl acrylate It can be seen that in the combined (B) latex, the one having a small amount of unsaturated acid has a small effect of improving impact resistance, and the one having a large amount thereof deteriorates the latex stability after blending.

Example 3 An acrylic elastic latex was obtained in the same manner as in Example 1 (a) except that 2-ethylhexyl acrylate was used as the alkyl acrylate instead of n-butyl acrylate. Three kinds of graft copolymers were obtained by changing three kinds of the amount of the monomer mixture to be graft-polymerized to 100 parts (as a solid content) of the acrylic elastic body as shown in Table 3. However, 0.75% was used as an additional emulsifier with respect to the monomer mixture in which potassium oleate was graft-polymerized. Further, sodium formaldehyde sulfoxylate and tertiary butyl hydroperoxide were used as polymerization initiators in an amount of 0.3% and 0.35%, respectively, with respect to the monomer mixture for graft polymerization. The ratio of each monomer in the graft-polymerized monomer mixture is 75
%, Styrene 15%, and acrylonitrile 10%.

The resulting graft copolymer (A)
100 parts (as solid content) of the latex was blended with 2 parts (as solid content) of the copolymer (B) latex obtained in (2) of Example 1, respectively, and the same procedure as in (3) of Example 1 was performed. To obtain a polymer. This polymer was treated in the same manner as in (4) of Example 1 to obtain a vinyl chloride resin composition.

Table 3 shows the results of measuring the impact resistance of these vinyl chloride resin compositions by the same evaluation method as in (4) of Example 1.

[0052]

[Table 3]

Example 4 In (1) of Example 1, n-octyl acrylate was used as the alkyl acrylate and 0.5 part of triallyl isocyanurate was used as the polyfunctional crosslinking agent. The same operation as in () was performed to obtain an acrylic elastic body. To 100 parts (solid content) of this acrylic elastic body, 59.6 parts of methyl methacrylate and 0.4% triallyl cyanurate.
The mixture of parts was operated in the same manner as in (1) of Example 1 to obtain a graft copolymer (A) latex.

This graft copolymer (A) latex 1
00 parts (as solid content) was blended with 3 parts (as solid content) of the copolymer (B) latex obtained in (2) of Example 1 and the polymer was recovered in the same manner as (3) of Example 1. Then, the same procedure as (4) of Example 1 was carried out to obtain a vinyl chloride resin composition. Table 4 shows the results of measuring the impact resistance of this vinyl chloride resin composition by the same evaluation method as (4) of Example 1. Table 4 also shows the results obtained by changing the amounts of the polyfunctional crosslinking agent in the acrylic elastic body and the graft layer.

[0055]

[Table 4]

The abbreviations in Table 4 are as follows.

OA: n-octyl acrylate TAIC: triallyl isocyanurate MMA: methyl methacrylic acid From the above results, the impact resistance improving effect is obtained when the amount of the polyfunctional crosslinking agent in the acrylic elastomer is too large or too small. Can be seen to decrease.

Example 5 Methyl methacrylate-butadiene-styrene resin (MBS resin) and chlorinated polyethylene (ClPE), which are commercially available PVC modifiers, and the modifications obtained in (1) to (3) of Example 1. The bulking agent was operated in the same manner as in (4) of Example 1 to obtain a vinyl chloride resin composition. Table 5 shows these weather resistances.
The weather resistance is indicated by the Izod impact strength and the degree of coloring after the accelerated exposure treatment with a weatherometer (Toyo Rika WE-II type).

[0059]

[Table 5]

The indication of the degree of coloring in the table is as follows. ◯: Almost no coloration and good. Δ: Slightly colored, which is not preferable. X: Colored and defective.

From the results shown in Table 5, it can be seen that the modifier according to the present invention has very good weather resistance (initial impact retention rate, coloration) as compared with the commercially available MBS resin and ClPE.

Example 6 30 parts of the modifier obtained in (1) to (3) of Example 1, 70 parts of a polycarbonate resin, 0.2 part of an antioxidant and 0.1 part of calcium stearate were placed in a Henschel mixer. 30m with the cylinder temperature set to 240 ℃
Pelletized with an mφ extruder. After drying, a test piece was prepared by an injection molding machine, and the impact strength was measured by the same evaluation method as in (4) of Example 1 and the results are shown in Table 6. The results of various changes in the addition amount of the copolymer (B) are also shown in Table 6.

[0063]

[Table 6]

As described above, the modifier according to the present invention exhibits a good impact resistance improving effect on the polycarbonate resin.

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Claims (2)

[Claims] 1. An acrylic elastomer mainly composed of an acrylic acid alkyl ester, which contains 100 parts by weight of a thermoplastic resin and 0.1 to 5% by weight of a polyfunctional crosslinking agent, and a methacrylic acid alkyl ester and an aromatic compound. 95 to 100% by weight of at least one monomer selected from the group of monomers consisting of a vinyl compound and a vinyl cyan compound, and a polyfunctional crosslinking agent 0 to
Graft copolymer (A) obtained by graft-polymerizing 5% by weight of a monomer or a mixture of monomers in one or more stages
Copolymer (B) 0.1-20 obtained by copolymerizing 100 parts by weight of unsaturated acid monomer 3-30% by weight and vinyl monomer 97-70% by weight copolymerizable therewith. A thermoplastic resin composition comprising 3 to 50 parts by weight of an impact resistance modifier having 3 parts by weight of good weather resistance and good weather resistance, impact resistance and molding processability. 2. A thermoplastic resin composition, wherein the resin mixed with the impact modifier according to claim 1 is at least one thermoplastic resin selected from vinyl chloride resins and polycarbonate resins.