JPS59161455A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a composition having high heat-deformation temperature and impact strength and excellent productivity, by compounding a multi-component copolymer obtained by the suspension polymerization of a specific vinyl monomer mixture, with a graft copolymer of a rubbery polymer and a specific vinyl monomer. CONSTITUTION:The objective composition is obtained by compounding (A) 50- 90pts.wt. of a multi-component copolymer obtained by the suspension polymerization of a mixture composed of 20-80wt% of p-alkylstyrene of formula (R1, R2 and R3 are H or methyl), 10-70wt% of alpha-methylstyrene, 10-45wt% of acrylonitrile, and 0-35wt% of other vinyl monomers, copolymerizable with the above monomers, and (B) 10-50pts.wt. of a graft copolymer obtained by polymerizing 80-30pts.wt. of a vinyl monomer selected from aromatic vinyl monomers, vinyl cyanide monomers and (meth)acrylic monomers in the presence of 20-70pts.wt. of a rubber polymer. The p-alkylstyrene in the component A is preferably p- methylstyrene, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermoplastic resin composition having an excellent balance of impact resistance, heat resistance and productivity.

Graft copolymers obtained by graft polymerizing vinyl monomers such as styrene, acrylonitrile p, and methyl methacrylate in the presence of rubbery polymers such as diene rubbers are called ABB resins and MABS resins. It is widely used as a chemical, and much research has been conducted on improving its manufacturing method and quality. In improving the quality of these graft copolymers, improving heat resistance in particular is a major issue, and a typical method for achieving this is to improve How to change all parts to α-methylstyrene, specific details
(1) A method of graft polymerizing α-methylstyrene and methacrylic acid p to a diene rubber-like polymer under suspension polymerization conditions (Japanese Patent Publication No. 57-697, Japanese Patent Publication No. 39/1989)
(20511 publication) and (2) diene-based comb-like polymer f, a graft copolymer obtained by graft polymerization of styrene and acrylonitrile, and a copolymer obtained by emulsion polymerization of acrylonitrile and a predominant amount of a-methylstyrene. Examples include a method of mixing polymers (Japanese Patent Publication No. 35-18194).

However, method (1) requires an extremely long time for graft polymerization due to the difficulty of polymerization of α-methylstyrene, and method (2) requires emulsion polymerization, making the polymer recovery process complicated. However, there is a problem in that it is difficult to avoid contamination with impurities.

On the other hand, para-alkylstyrenes such as Haller tertiary-butylstyrene (pt-methylstyrene) and para-methylstyrene (p-lflV7 styrene) have good polymerizability and are more polymerizable than styrene. Because of the high heat deformation humidity of these para-alkylstyrenes, heat-resistant resins using homopolymers or copolymers of these para-alkylstyrenes have been proposed.

(U.S. Patent No. 2,725,261, U.S. Patent No. 3,4
26.10! No. 1, Special Publication No. 55-4780 and Ace Polymer Preprints, No. 23
Vol. 2, No. 96, September 1982, etc.) However, the heat distortion temperature of resins produced using these para-alkylstyrenes is higher than that of resins mainly composed of styrene, such as ABe resin. However, it is still insufficient and does not have satisfactory heat resistance.

Therefore, the present inventors have a high heat distortion temperature and #impact strength,
As a result of intensive studies aimed at obtaining a thermoplastic resin composition with uncertain productivity, we found a vinyl monomer mixture with a specific composition containing para-alkylstyrene and a-methylstyrene. By mixing in a specific ratio a multicomponent copolymer obtained by turbid polymerization and a graft copolymer obtained by graft polymerization of a rubber-like polymer (e), a specific vinyl monomer (mixture), the above purpose can be achieved. The present invention has been achieved by discovering that this can be achieved efficiently.

That is, the present invention (A) para-alkylstyrene 20-
80% by weight, α-methylstyrene 10-70% by weight, acrylonitrile/l/10-45% by weight, and 0-23% by weight of other vinyl A/based monomers copolymerizable with these monomers. 50 to 90 parts by weight of a multicomponent copolymer obtained by suspension polymerization of a monomer mixture and (B) 20 to 7 parts by weight of a rubbery polymer
80 to 30 parts by weight of at least one vinyl monomer selected from aromatic vinyl monomers, vinyl cyanide monomers, and (meth)acrylic acid monomers.
The present invention provides a thermoplastic resin composition comprising 10 to 50 parts by weight of a graft copolymer obtained by polymerizing parts by weight.

In the production of general vinyl-based polymers, the exposure polymerization method is superior in productivity compared to the emulsion polymerization method in that the polymer can be easily recovered. However, when a vinyl monomer mixture containing σ-methylene p-styrene is subjected to suspension polymerization, there is a problem in that the polymerization rate is extremely slow.

On the other hand, monomer mixtures containing para-alkylstyrene such as pt-butystyrene and p-methylstyrene can be easily suspension polymerized, and the resulting polymer has a sufficient heat distortion temperature. A vinyl monomer mixture having the above composition containing para-alkylstyrene and α-methylstyrene can be easily polymerized by suspension polymerization. The resulting multicomponent copolymer has a high heat distortion temperature. Furthermore, by mixing the obtained multi-component copolymer with the above-mentioned graft copolymer, a thermoplastic resin composition having both heat resistance and impact resistance can be obtained.

The multicomponent copolymer (A) in the present invention is para-alkyl styrene 20 to 80% by weight, and (25 to 70% by weight,
σ-Methylnutylene 10-70% by weight, especially 20-70%
60% by weight, 10-45% by weight of acrylonitrile, especially 15-40% by weight, and 0-55% by weight of other vinyl monomers copolymerizable with these monomers, especially 0-55% by weight.
It is obtained by suspension polymerization of 30% by weight using water as a medium.

The para-alkylstyrene used in the production of multicomponent copolymers (gradients) refers to the para-alkylstyrenes represented by the general formula l2 (wherein R, R, and R3 represent hydrogen or megthyl groups). This is a styrene derivative having an alkyl substituent.Specific examples include p-methylstyrene, p-ethylstyrene, p-isopropylene, p-butylene, and especially p-methylstyrene and p-methylstyrene. -t-butylstyrene is preferably used.

The para-alkylstyrene used in the present invention may contain ortho- and/or meta-isomers as long as the effects of the present invention are not impaired, but it usually contains 80% by weight of para-alkylstyrene, preferably The one containing 90% by weight or more is used.

The multi-component copolymer (A) is obtained mainly by copolymerizing para-alkyl styrene, α-methylstyrene and acrylonitrile, but if desired, it can also be obtained by copolymerizing a small proportion of other copolymerizable vinyl monomers. You can. There are no particular restrictions on the other vinyl monomers that can be copolymerized, but specific examples include aromatic vinyl monomers such as styrene, and (
A meth)acrylic acid monomer or the like can be used.

Furthermore, isomers at the ortho and meta positions of para-alkylstyrene can also be used.

In the multi-component copolymer (A)t of the present invention, if the content of para-alkylstyrene is less than 20% by weight, the polymerization rate becomes extremely slow, making it difficult to complete the polymerization by suspension polymerization, and If it exceeds %, the heat distortion temperature of the resulting copolymer will decrease and sufficient heat resistance will not be obtained, which is not preferable. Multi-component copolymer (A) If α-methylstyrene is less than 10% by weight, the resulting copolymer will have an insufficient heat distortion temperature, and if it exceeds 70% by weight, the polymerization rate will decrease, This is not preferred because it is difficult to complete the polymerization using the suspension polymerization method. Multicomponent copolymer (if the acrylonitrium μ is less than 10% by weight, a resin composition with excellent impact resistance cannot be obtained, and if it exceeds 45% by weight, the moldability and thermal stability of the resin composition will decrease, so it is preferable. do not have.

Suspension polymerization is essential for the polymerization method of the multi-component copolymer (A). In solution polymerization, recovering the solvent is complicated, and in emulsion polymerization, recovering the polymer is not only complicated, but also the recovery of the polymer. This is not preferred because impurities such as emulsifiers tend to remain and excellent heat resistance cannot be achieved.

The method of suspension polymerization of the multi-component copolymer (A) is not particularly limited and can be carried out by any commonly known method.

For example, an inorganic or This is carried out by polymerization under vigorous stirring in the presence of an organic S clouding agent. The monomer mixture may be charged in its entirety into the polymerization tank at the beginning of the polymerization (or, some of the monomers may be charged in advance and the remaining amount may be charged continuously or in one batch at a time). In addition, a chain transfer agent, a lubricant, etc. may be mixed with the monomer mixture (e). 8BR), diene-based comb-like polymers such as acrylonitrilene tadiene copolymer rubber (NBR),
Acrylic acid copolymer rubber such as polybutyl acrylate and ethylene-propylene-nonconjugated diene copolymer (
KPDM) Aromatic vinyl monomers such as styrene, vinyltonolenine, t-butylstyrene, etc., cyanide vinyl p-based monomers typified by acrylonitrile, in the presence of 20 to 70 parts by weight of a rubber-like enriched polymer such as rubber; Methyl methacrylate
and one or more vinyl monomers selected from the (meth)acrylic acid monomers represented by methyl acrylate 80
This is obtained by polymerizing ~30 parts by weight.

If the proportion of the rubbery polymer in the graft copolymer (B) is less than 20 parts by weight, it is difficult to obtain a resin composition with a good balance between impact strength and heat distortion temperature, and if it exceeds 70 parts by weight, it is sufficient. This is not desirable because graft polymerization becomes difficult and sufficient impact strength cannot be obtained.

There are no particular restrictions on the polymerization method for the graft copolymer.
Generally known methods are used, such as emulsion polymerization, emulsion-suspension polymerization, solution polymerization, and suspension polymerization. Polymerization initiator t
Although there is no particular restriction on this, radical generating initiators such as organic and non-profitable peroxide-based initiators are usually used. Any method can be used to introduce the monomer mixture into the polymerization system, including adding it all at once at the beginning, adding it continuously during polymerization, or changing the composition of the monomer mixture during polymerization. A method of controlling the composition of the graft copolymer can also be used. It is also possible to use a chain transfer agent in combination, if necessary.

In the thermoplastic resin composition of the present invention, a multicomponent copolymer (
Gradient and graft copolymer (the average mixing ratio is 50 to 90 parts by weight of multi-component copolymer (A) to 50 to 90 parts by weight of graft copolymer (
b) is 10 to 50 parts by weight. Mixing ratios other than this are not preferred because it is difficult to obtain a resin composition that is superior in both heat distortion temperature and impact strength.

In the production of the thermoplastic resin composition of the present invention, a multi-component copolymer (gradient and graft copolymer) is produced. Although there are no particular restrictions regarding the mixing method, an extruder or kneader is usually used. The mixture is melt-mixed using

The thermoplastic resin composition of the present invention may also contain other polymers, such as nutylene-acrylonitrile copolymer, nutylene-methyl methacrylate-acrylonitrile copolymer, styrene-α-methylstyrene-acrylonitrile copolymer, etc. Desired performance can be adjusted by mixing a nitrile copolymer, a-methylnutylene-acrylonitrile copolymer, etc. In addition, various stabilizers, lubricants, additives,
Flame retardants, colorants, glass and metal fibers, reinforcing agents, fillers, etc. can also be mixed.

Hereinafter, the present invention will be explained by reference examples, examples, and comparative examples.
Let me explain in more detail. Parts and q represent parts by weight and % by weight, respectively. Heat distortion temperature is ASTM D
-648-56, Izot impact strength is ASTM D
-256-56Method A. The polymerization rate was measured by dissolving the polymer in a solvent (dimethylformamide) and quantifying the residual monomer using a Ganuchromatography.

Reference Example 1 (Multicomponent copolymer (manufacture of gradient)) 100 parts of a monomer mixture having the composition shown in Table 1 was mixed with 200 parts of pure water and 0.2 parts of acrylamide-methyl methacrylate copolymer (suspending agent). and 0.5 parts of sodium phosphate under high-speed stirring to form a suspension, and suspension polymerization was carried out under predetermined polymerization conditions (polymerization temperature and polymerization time). After the polymerization was completed, it was cooled. The mixture was washed with water, filtered and dried to obtain granular multi-component copolymers A-1 to A-12.

The polymerization temperature was as follows except for A-3.

The temperature was gradually raised from 70°C to 90°C over 300 minutes, then raised to 105°C over 10 minutes, and held at that temperature for 60 minutes to complete the polymerization. Only for A-5, the following polymerization temperature conditions were adopted. The temperature was maintained at 90° C. for 500 minutes, then the temperature was raised to 110° C. over 10 minutes, and the temperature was maintained at that temperature for 60 minutes.

Usually, the monomer mixture was charged in its entirety at once at the beginning, but only A-2 and A-3 were charged in the following manner. A
In -2, only α-methylstyrene was divided into four equal parts and charged at the initial, 30th, 60th, and 150th minutes. In A-1t, 4 out of 100 parts of the total monomer mixture
0 parts was initially charged, and the remaining amount was charged at constant speed over 120 minutes from the start of polymerization.

The obtained multicomponent copolymer was used in the following Examples and Comparative Examples, but only A-12 had a low final polymerization rate, so it was used after removing residual monomers by steam distillation.

(Blank below on this page) Reference Example 2 (Production of graft copolymer (B)) Graft copolymers B-1 to B-3 and B-5 were prepared using the following emulsion polymerization recipe.
, B-6 was produced. 120% pure water in a nitrogen-substituted polymerization tank
part, glucose 0.5 part, sodium pyrophosphate 0.5 part, ferrous sulfate o, oos part, and a predetermined amount of polybutadiene latex shown in Table 2 were charged while controlling the temperature to 60°C. Next, the monomer mixture shown in Table 2t was added at a constant rate over 5 hours, and 30 parts of pure water, 2.5 parts of potassium oleate, and 0.0 parts of cumene hydroperoquine were added from another charging port.
Two parts of the aqueous solution were added uniformly over a period of 6 hours. After the addition was completed, the temperature was raised to 75°C and polymerization was continued for an additional hour. After the polymerization was completed, the polymer was coagulated with magnesium sulfate, washed, dehydrated, and dried to obtain a powdery graft copolymer.

B-4 was polymerized by the following method. Table 2 in the polymerization tank with nitrogen substitution? The indicated amount of ethylene-propylene-nonconjugated diene copolymer rubber (manufactured by Mitsui Petrochemical Industries, Ltd., Mitsui EPT40)
70), styrene, and acrylonitrile were charged together with 110.5 parts of pencil peroxide, 150 parts of toluene, and 150 parts of n-hexane, stirred thoroughly to dissolve them, and then polymerized at 80°C for 5 hours. After the polymerization was completed, toluene, n-hexane and residual monomers were removed by steam distillation to obtain a graft copolymer (B-4).

Table 2 *1) PBD Polybutadiene latex (parts are converted to solid content) EPDM Ethylene-propylene-nonconjugated diene copolymer rubber (Mitsui Petrochemical Industries +
M, Mitsui FiPT4070) Examples and Comparative Examples Multi-component copolymers A-1 to A'-12 produced in Reference Example 1
and graft copolymers B-1 to B- produced in Reference Example 2
6 were mixed at the blending ratio shown in Table 3, 0.5 part of triphenyl phosphite was added as a stabilizer, and then melted and mixed in an extruder and pelletized. Next, each pellet was injection molded to create each evaluation test piece, and the physical properties were measured. The measurement results are shown in Table 6.

(Blank below on this page) Table 5 The following is clear from Table 3. The thermoplastic resin compositions (Ya 1 to 10) of the present invention have excellent mechanical properties represented by impact strength and thermal deformation temperature.

On the other hand, when the multi-component copolymer (A) contains only para-alkylstyrene and acrylonitrile but does not contain α-methylstyrene (12.13), when a styrene-acrylonitrile copolymer is used. (Jiill)r
Compared to this, although the heat distortion temperature is slightly higher, a sufficiently high heat distortion temperature cannot be obtained. When the multi-component copolymer (A) contains only α-methylstyrene and acrylonitrile and does not contain para-alkiflastyrene,
Not only does the polymerization rate not increase during suspension polymerization of the multicomponent copolymer (A-12), but the resulting resin composition (tK 1
2) Impact strength is extremely low. In addition, in the graft copolymer (B), when the proportion of the rubbery polymer exceeds 70 parts by weight (A15) or less than 20 parts by weight (
A16) provides only low impact strength.

In other words, the thermoplastic resin composition of the present invention has excellent heat resistance and impact resistance, as well as excellent productivity, so it is expected that it will be applied to various fields in the future by taking advantage of these characteristics. .

Patent applicant Higashi Shikikai Co., Ltd.

Claims (1)

[Claims] (A) - General formula (wherein RI s R1 and R3 are hydrogen or methyl
Show the base. ) para-alkylstyrene 20
-80% by weight, α-methyleneμ styrene 10 to 70% by weight,
Acrylonitrile A/10-45x amount and other vinyl ρ monomers copolymerizable with these monomers O-35% by weight
50 to 90 parts by weight of a multicomponent copolymer obtained by suspension polymerization of a monomer mixture consisting of (B) and 20 to 70 parts by weight of a rubbery polymer.
80 to 30 parts by weight of one or more vinyl monomers selected from aromatic vinyl monomers, vinyl cyanide monomers, and (meth)acrylic acid monomers. A thermoplastic resin composition prepared by mixing 10 to 50 parts by weight of a graft copolymer obtained by polymerizing parts by weight.