JPS6386707A - Production of heat-resistant polymer - Google Patents

Abstract

PURPOSE:To obtain a polymer outstanding in heat and impact resistances and fluidity in the molding, by polymerization of two or more kinds of monomer in the presence of a rubbery polymer, in which the maleimide monomer is added after the phase conversion of the rubbery polymer instead of adding at the beggining. CONSTITUTION:In carrying out bulk or bulk-suspension polymerization of a monomer mixture comprising a maleimide monomer (e.g., N-phenyl maleimide, N-cyclohexyl maleimide, accounting for 3-40wt%), aromatic vinyl compound (e.g., styrene, accounting for 40-80wt%) and unsaturated nitrile compound (e.g., acrylonitrile accounting for 10-30wt%) in the presence of a rubbery polymer such as polybutadiene or styrene-butadiene rubber (pref., in general, accounting for 5-15wt%). The monomers except the maleimide one are involved in the reaction; and after the virtual phase conversion of the rubbery polymer, said maleimide monomer is added to the system to proceed with the polymerization, thus obtaining the objective polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a heat-resistant polymer that has excellent heat resistance and impact resistance, and also has good fluidity during molding.

[Prior art and its problems]

Conventionally, styrene and acrylonitrile are bulk polymerized in the presence of a diene rubber such as polybutadiene, the diene rubber is dispersed in the form of particles in a styrene-acrylonitrile copolymer matrix, and then converted to a suspension polymerization system for further polymerization. As a result, it is widely practiced to manufacture so-called ABS resin.

On the other hand, in order to improve the heat resistance of ABS resin, N-
Recently, it has become popular to copolymerize phenylmale with a maleic monomer such as do to obtain a quaternary copolymer.
1-162510, etc.).

However, in the presence of butadiene rubber, styrene,
When a specific polymer obtained by copolymerization of acrylonitrile (N-phenylmaleimide) is molded by extrusion molding, injection molding, etc., the surface of the molded product becomes rough and there is a problem that it cannot be put to practical use.

[Kth means for solving the problem] Therefore, in the present invention, in the presence of rubber, an aromatic vinyl compound such as styrene and an unsaturated nitrile compound such as acrylonitrile are first added and polymerized in a bulk polymerization system. The above problems were solved by proceeding with the process, adding a maleimide monomer such as N-phenylmaleimide after the rubber had undergone substantial phase conversion, and proceeding with polymerization in a bulk polymerization system or suspension polymerization system.

The method for producing a heat-resistant polymer of the present invention involves polymerizing three or more monomers such as a maleimide monomer, an aromatic vinyl compound, and an unsaturated nitrile compound in the presence of a rubbery polymer. First, a monomer other than the maleimide-based AAA is added to proceed with the polymerization, and after the rubber-like polymer undergoes substantial phase conversion, a maleimide-based monomer is added to proceed with the polymerization.

The rubbery polymers used in this invention include polybutadiene (FB)L), styrene-butadiene rubber (SBR
) and other diene rubbers are used. Regarding polybutadiene, it is preferable that the Munie viscosity (ML 100° C.) is in the range of 35 to 55, and the cis key is preferably 30 to 98%.

Further, as for styrene-butadiene rubber, it is desirable that the Muny viscosity is in the range of 35 to 55, and the cis content is also in the range of 30 to 98%, if necessary. The amount of this rubbery polymer to be used is determined by the polymerization of the impact strength required for the heat-resistant polymer to be obtained, and is usually 5% of the total amount.
It is used in a range of ~15 wt%.

The maleimide monomer used in the present invention is a compound represented by the following general formula.

R8 (In the formula, R,, R1, and R represent hydrogen, halogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group, or a cycloalkyl group) Specific examples of maleimide-based monoisomers Examples include maleimide, hemethylmaleimide, N
-Ethylmaleimide, N-butylmaleimide, N-laurylmaleimide, N-phenylmaleimide, N-o-
the law of nature.

Examples include luphenylmaleimide and N-cyclohexylmaleimide, and 18il or 281 or more of these are used, with N-phenylmaleimide and N-cyclohexylmaleimide being particularly preferred.

The amount of maleimide monomer used is determined depending on the degree of improvement in heat resistance, but is usually 3 to 40 wt% based on the total amount.
It can be determined within the range of Generally, the addition of N-phenylmaleido flaws increases the heat resistance temperature of the obtained polymer by 1.5 to 2°C.

As the aromatic vinyl compound, two or more types of 1at-th&H such as styrene, α-methylstyrene, p-methylstyrene, t-butylstyrene, and chlorostyrene are used, and styrene and chlorostyrene are particularly preferred. The amount of this aromatic vinyl compound used is 40 to 40g based on the total amount.
It can be determined as appropriate within the range of Q wt .

Examples of the unsaturated nitrile compound include acrylonitrile, metacyclonitrile, fumaronitrile, maleonitrile and the like, and one or more of these can be used, with acrylonitrile being preferred.

Nine, the amount of unsaturated nitrile compound used is 10 to 3 of the total amount.
Although it is set to be about 0 wt%, it is not limited to this range.

Furthermore, in the present invention, in addition to the above-mentioned monomers, acrylic acid esters such as methyl acrylate, methacrylic powder esters such as methyl methacrylate, etc. can be used at the same time as necessary. The amount of monomer such as methyl methacrylate used is usually 0 to 30% of the total amount.
wt1, and is determined according to the required characteristics.

Next, the polymerization method will be specifically explained.

First, the above-mentioned rubbery polymer is dissolved in an aromatic vinyl compound such as styrene, an unsaturated nitrile compound such as acrylonitrile, and a monomer such as methyl methacrylate added as necessary, and lauryl peroxide is added as a polymerization initiator. oxide, benzoyl peroxide, t-butyl perlaurate, t-butyl perbenzoate, and other organic peroxides, azobisisobutyronitrile, etc., at a ratio of 0.1 to 0.5 vt relative to the total monomer amount. 0.05 to 0.5 wt based on the total monomer amount of mercaptans such as n-octylmercaptan, n-dodecylmercaptan, t-dodecylmercaptan, etc. as a chain transfer agent.
48111 and polymerized for 1 to 5 hours at 50 to 80°C using a bulk polymerization system. Through this polymerization, the above-mentioned monomers are copolymerized, and some of them are graft-polymerized to the rubber-like polymer, so that the amount of monomers decreases. On the other hand, in the insect repellent nine copolymer, the rubber-like polymer and the monomer are distributed in one part, and the two solutions are phase-separated.As the polymerization progresses, the volume of the copolymer solution increases, and a phase transformation occurs at a certain point. , the rubbery polymer is dispersed in the form of particles in the monomer-copolymer solution.

The polymerization rate of the monomer mixture at this point is about 20-30%.

After this phase conversion, a maleimide monomer is added to the polymerization system to further advance the polymerization. At this time, the previous bulk polymerization system is
The polymerization may proceed continuously, or the polymerization may proceed by converting from a bulk polymerization system to a suspension polymerization system.

When proceeding with the polymerization in a bulk polymerization system, a small amount of Kamikiei initiator is additionally added, and the polymerization is proceeded at 60 to 120° C. for 1 to 5 hours.

When converting to a suspension polymerization system, the entire reaction system is suspended in 1 to 2 times the amount of pure water. This vA.

As a dispersant (suspending agent), add 0.1 to 1 wt of @3 calcium phosphate soap to water. Furthermore, 1 [combined starting 1111 currency is added, 70
Polymerization is carried out with stirring at ~140°C for 4-7 hours. On this occasion,
Polymerization may be carried out by changing the temperature cycle.

In addition to adding the maleimide monomer in its entirety at once, it is also possible to add it gradually.

Through this secondary polymerization, the maleimide monomer.

It is copolymerized with the remaining aromatic vinyl compound, unsaturated nitrile compound, etc. to obtain the desired heat-resistant polymer.

The Ft2 heat-resistant enriched material thus obtained can be molded using an extruder or injection molding machine with appropriate noise, and the resulting J-shaped product is
Excellent foreign bonds with no rough skin due to good melt fluidity,
It exhibits P-side Motozawa et al. Ill Hayabusa! i! High IK and high heat resistance.

In the production method of the present invention, the rubbery polymer is dispersed in the form of particles, undergoes phase transformation, and after t, the maleimide monomer is added and polymerized, so that the rubber phase is not made into particles. Complete and uniform dispersion of rubber particles. Therefore, the melt flowability of the single polymer is good, and a molded article with an excellent appearance without rough skin can be obtained.

In the case of conventional aromatic vinyl compounds, which are maleate-based monomers, which are polymerized at the same time as unsaturated and tolyl compounds, the particle formation of this rubber phase is incomplete, resulting in non-uniform dispersion, resulting in poor dissolution of the polymer. This results in poor mobility. The state of granulation of the rubber phase is confirmed by observation using a phase contrast microscope.

〔Example〕

Below, examples will be shown to clarify the functions and effects.

In addition, "parts" and "regret" are all parts by weight.

(*Ml) Polybutadiene 151Rs, styrene 63.8ffi,
It was completely dissolved in 21.3 parts of acrylonitrile, and 0.2 parts of lauroyl peroxide as a polymerization initiator and 0.1 parts of t-dodecyl mercaptan as a chain transfer agent were added thereto, and bulk polymerization was carried out at 70°C for 2.5 hours. .

As a result, the polybutadiene completed its phase transformation and was stably formed into particles. The polymerization rate of the monomer mixture at this point is 2
At 24. Here, the reaction was temporarily stopped, 21.3 parts of N-phenylmaleimide was added, and the entire mixture was diluted with 1 part of water.
681! I! S cloudy inside.

As a suspending agent, a calcium soap was used.

To this suspension, 0.2 ml of lauroyl peroxide and 0.2 ml of t-butyl peroxylaure were added as polymerization initiators.
Add 241 and heat at 80°C for 2 hours.

Raise the temperature at 120'C1 for 1 hour, % 120°C for 2 hours,
The temperature was further raised to 135°C in 1 hour to complete the polymerization.90 Properties of the resulting heat-resistant polymer! -1 is a friend.

(Execution M2) The 10W polybutadiene & 9 staples were obtained in the same manner as in Example 1, using a heat-resistant polymer. The properties of this product are shown in Table 1.

(Example 3) Nine heat-resistant polymers were obtained in the same manner as in Example 11 using styrene-butadiene rubber instead of polybutadiene. The properties of this product are shown in Table 1.

(Example 4) A polymer was obtained in the same manner as in Example 1 except that 21.3 parts of acrylonitrile was replaced by a warm mixture of 15 parts of acrylonitrile and 6.3 parts of methyl methacrylate. The properties of this are shown in Table-1.

(Example 5) A polymer was obtained in the same manner as in Example 1 except that N-cyclohexylmaleimide was used instead of N-phenylmaleimide. The properties of this are shown in Table-1.

(Example 6) A polymer was obtained in the same manner as in Example 1 except that 7.0 parts of polybutadiene was used. The properties of this are shown in Table-1.

(Comparison gAJ1) Add N-phenylmaleimide from the beginning and then carry out 4i
A polymer was obtained in the same manner as yrU6. In this case, the polybutadiene was not sufficiently pulverized. The properties of the polymer are shown in Table 1.

In Table I, as is clear from the comparison of Example 6 and Comparative Example 1, in Comparative Example 11, the dispersion of rubber particles was incomplete, the appearance of the molded product was poor, and the composition was the same. Despite this, it can be seen that the softening point, tensile strength, and impact strength are also inferior to Example 6.

[Effects of the Invention] As explained above, according to the method for producing a heat-resistant polymer of the present invention, even in a maleimide monomer copolymer system, the rubber-like polymer is completely formed into particles, and the rubber-like polymer is completely formed into particles. A uniformly dispersed system of shaped polymer particles is obtained. Second, the polymer has good melt flowability, making it possible to obtain molded products with a good appearance without rough skin, and because the rubber phase is homogeneously dispersed, the softening point, tensile strength, and impact strength are also high. Polymers can be obtained.

Showa Denko Co., Ltd.

Claims (1)

[Claims] A method for carrying out bulk polymerization or bulk-suspension polymerization of monomers mainly consisting of maleimide monomers, aromatic vinyl compounds, and unsaturated nitrile compounds in the presence of a rubbery polymer. , First, a monomer other than the maleimide monomer is added to the rubbery polymer to proceed with polymerization, and after the rubbery polymer has substantially undergone phase conversion, a maleimide monomer is added to proceed with the polymerization. A method for producing a heat-resistant polymer characterized by: