JPH0445145A - Flame-retardant impact-resistant resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition having excellent thermal stability in molding, heat-resistance, solvent resistance and rigidity and suitable for appliance part, etc., by compounding specific amounts of a vinyl chloride polymer having a specific polymerization degree with two kinds of rubbery graft copolymers and a compatibilizing agent. CONSTITUTION:The objective composition is produced by compounding (A) 30-60pts.wt. of a vinyl chloride polymer having an average polymerization degree of 400-1,700 with (B) 10-50pts.wt. of a graft polymer of (B1) 5-30wt.% of a rubbery polymer having a glass transition point of <=25 deg.C (e.g. polybutadiene rubber) and (B2) 70-95wt.% of an aromatic vinyl compound (e.g. styrene), (C) 5-20pts.wt. of a graft copolymer composed of (C1) 40-90wt.% of a rubbery polymer having a glass transition point of <=25 deg.C, (C2) an aromatic vinyl compound (e.g. styrene) and (C3) a methacrylic acid ester (e.g. methyl methacrylate) (the sum of the components C2 and C3 is 10-60wt.%) and (D) 3-20pts.wt. of a compatibilizing agent.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a novel flame-retardant and impact-resistant resin composition, and more specifically, a composition that has thermal stability during processing, heat resistance, solvent resistance, and rigidity. The present invention relates to a flame-retardant and impact-resistant resin composition.

[Conventional technology]

Styrene-based resins have excellent moldability and dimensional stability, as well as rigidity and electrical insulation properties, so they are used in a wide variety of fields including home appliance parts and OA equipment parts. Its use is limited due to its flammability.

To make styrene resin flame retardant, a method of adding a flame retardant or a method of blending a flame retardant resin is used. As the former method, it is known to add a halogenated organic compound, but in order to have sufficient flame retardancy, a large amount is required, resulting in discoloration during molding and This poses many problems as it often has an adverse effect or reduces the heat resistance and weather resistance of the resin composition.

On the other hand, the latter method involves blending polystyrene with vinyl chloride resin, which is a typical flame-retardant resin. The strength of the resulting polymer composition is also low. (See Comparative Example 1 described below) As an example of compatibilization between vinyl chloride resin and styrene resin, Japanese Patent Publication No. 57-26616 describes (A) acrylonitrile-styrene copolymer and (B) vinyl chloride resin. A flame-retardant resin composition consisting of a polymer and (C) a methyl methacrylate-containing polymer has been disclosed, but although it has excellent flame retardancy, it does not contain a rubber component and therefore has low impact resistance. Different from the resin composition of the invention. Moreover, in Japanese Patent Publication No. 57-56939, (D) Chloride 1. :”Nyl-based resin, (B) styrene-based graft resin consisting of butadiene, styrene, acrylonitrile, and methyl methacrylate, (F) styrene-based resin, and (G) ethylene-
Flame retardant resin compositions made of vinyl acetate-vinyl chloride graft resins or chlorinated polyethylene have been disclosed;
It differs from the resin composition of the present invention in that the above (G) is an essential component.

Furthermore, in Japanese Patent Application Laid-Open No. 57-42754, (H)
A thermoplastic resin composition comprising polystyrene, (I) polyvinyl chloride, and (J) a chlorinated styrene-butadiene block copolymer has been disclosed, but the present invention is unique in that the above (J) is an essential component. Different from resin composition.

In addition, Japanese Patent Publication No. 60-16469 discloses that (K) a monomer consisting of a monovinyl aromatic monomer, an unsaturated nitrile monomer, and an α,β-monoolefinic unsaturated carboxylic acid derivative in a rubbery polymer. A resin composition comprising a graft polymer grafted with a mixture of polyester, (L) a monovinyl aromatic monomer, (M) polyvinyl chloride, and (N) chlorinated polyethylene is disclosed. It differs from the resin composition of the present invention in that it is an essential component. On the other hand, JP-A-62-
Publication No. 39653 discloses (D) styrene resin and (P
) A flame retardant resin composition comprising a vinyl chloride resin, (Q) an organotin compound and a cyanurate derivative, and JP-A No. 6
Publication No. 0-166337 discloses a resin composition comprising (R) a vinyl chloride resin, (S) an α-methylstyrene-acrylonitrile copolymer, and (T) an impact reinforcement agent. Because the vinyl chloride resin is reinforced with a single impact-resistance reinforcing agent, it has the effect of improving impact resistance, but the heat resistance and rigidity are significantly reduced, which limits its industrial use. As a result of intensive research into improving the strength of vinyl chloride polymers, the present invention has made it possible to improve rigidity and heat resistance while maintaining impact resistance by combining two types of rubber-like graft copolymers. Ta.

[Problem to be solved by the invention]

In view of the current situation, the present invention aims to provide a flame-retardant and impact-resistant resin composition that does not have the above-mentioned problems, that is, has thermal stability during processing, heat resistance, solvent resistance, and rigidity. This is the purpose.

[Means to solve the problem]

That is, the present invention comprises: (1) (A) 30 to 60 parts by weight of a vinyl chloride polymer having an average degree of polymerization of 400 to 1,700; (B) a rubbery polymer having a glass transition point (Tg) of 25°C or lower and an aromatic composition; Graft polymer with group vinyl compound 10-5
0 parts by weight, (C) 5 to 20 parts by weight of a graft copolymer of a rubbery polymer having a glass transition point (Tg) of 25° C. or less, an aromatic vinyl compound, and a methacrylic acid ester, and (D) a compatibility improver. The present invention provides a flame-retardant and impact-resistant resin composition comprising 3 to 20 parts by weight.

The present invention will be explained in detail below.

The resin composition of the present invention comprises a specific vinyl chloride polymer (hereinafter abbreviated as polymer a) and a graft polymer of a rubbery polymer and an aromatic vinyl compound (hereinafter abbreviated as polymer). , a graft copolymer of a rubbery polymer, an aromatic vinyl compound, and a methacrylic ester (hereinafter abbreviated as polymer C), and a methacrylic ester, an aromatic vinyl compound, and a copolymer thereof as a compatibility improver. A copolymer of a possible copolymer (hereinafter referred to as polymer d) or a copolymer of an unsaturated nitrile compound, an aromatic vinyl compound, and a copolymer that can be copolymerized with these (hereinafter referred to as polymer d) (abbreviated as e) results in surprising advantages.

First, the polymer a is a vinyl chloride homopolymer or a copolymer containing 70% by weight or more of vinyl chloride units, and its production method is by a known bulk polymerization method, suspension polymerization method, or emulsion polymerization method. Here, the average degree of polymerization of polymer a is 400
~1700 is essential. When this average degree of polymerization is less than 400, the impact resistance of the resulting resin composition is low;
If it exceeds 1,700, blending with the polymer, c, and compatibility improver will be poor, the resin composition will deteriorate, the appearance of the molded product will turn brown, and the product value will be significantly impaired.

On the other hand, the polymer is obtained by graft polymerizing an aromatic vinyl compound in the presence of a rubbery polymer.

Here, the aromatic vinyl compounds include styrene, α-methylstyrene, vinyltoluene, 10genated styrene, etc., and the content thereof is 70 to 95% by weight in the polymer.
is preferred. If 70% by weight is not added, the fluidity decreases and 95%
If the weight percentage is exceeded, the impact resistance will decrease.

Furthermore, the rubbery polymers having a glass transition point (Tg) of 25°C or lower include polybutadiene rubber, styrene-butadiene copolymer rubber, ethylene-propylene-butadiene copolymer rubber, etc., and the content thereof is higher than that of the polymer. It is preferably 5 to 30% by weight. If it is less than 5% by weight, impact resistance decreases,
If it exceeds 30% by weight, heat resistance, fluidity, and rigidity will decrease.

Regarding the manufacturing method of the polymer, known bulk polymerization, bulk suspension polymerization, emulsion polymerization, etc. can be adopted, but rubber-like polymers,
Generally, a bulk polymerization method is used in which a homogeneous polymerization stock solution consisting of an aromatic vinyl compound and a polymerization solvent is supplied to a continuous multistage bulk polymerization reactor equipped with a stirrer, and is continuously polymerized and devolatilized.

Moreover, the polymer C is obtained by graft polymerizing an aromatic vinyl compound and a methacrylic acid ester in the presence of a rubbery polymer.

Here, aromatic vinyl compounds include styrene, α-methylstyrene, vinyltoluene, halogenated styrene, etc., and methacrylic esters include methyl methacrylate,
Ethyl methacrylate, propyl methacrylate, etc.
The total amount of both monomers is 10 to 60% by weight in polymer C.
is preferred.

If it is less than 10% by weight, fluidity decreases, and if it exceeds 60% by weight, impact resistance decreases.

Furthermore, the rubbery polymers having a glass transition point (Tg) of 25°C or lower include polybutadiene rubber, styrene-butadiene copolymer rubber, ethylene-propylene-butadiene copolymer rubber, etc., and the content thereof is higher than that of the polymer. Among C, 40 to 90% by weight is preferable. If it is less than 40% by weight, impact resistance will decrease, and if it exceeds 90% by weight, heat resistance, fluidity, and rigidity will decrease.

As for the method for producing the polymer C, known bulk polymerization, bulk suspension polymerization, emulsion polymerization, etc. can be employed.

For boat fishing, an emulsion polymerization method is selected in which the monomer is emulsion-graft polymerized in the presence of latex in which a rubbery polymer is dispersed in an aqueous medium.

The compatibility improver in the resin composition of the present invention may be any resin that is effective in making the vinyl chloride polymer and the styrene polymer compatible, and polymer d or polymer e is particularly effective.

Regarding polymer d, the essential component methacrylate ester is methyl methacrylate, ethyl methacrylate, propyl methacrylate, etc., and methyl methacrylate is particularly preferred. Another essential component, aromatic vinyl, is styrene, α-methylstyrene, paramethylstyrene, p-
Chlorostyrene, p-bromostyrene, 2,4.5-)
Libromostyrene, etc., and styrene is most preferred, but a copolymer consisting mainly of styrene mixed with the aromatic vinyl of the above type may also be used. As a component of this polymer d, one or more monomer components copolymerizable with the methacrylic ester and the aromatic vinyl may be introduced. Polymer a, b
If it is necessary to further improve the blendability with , c or to lower the melt viscosity during blending, use
An acrylic ester consisting of 8 alkyl groups can be used. Moreover, when it is necessary to improve the heat resistance of the resin composition, monomers such as acrylic acid, methacrylic acid, maleic anhydride, and N-substituted maleimide are selected. The number of methacrylic acid ester units in the composition of polymer d is 20
~100% by weight, aromatic vinyl units from 80 to 0% by weight,
The monomer units that can be copolymerized with these need to be in the range of 0 to 30% by weight; outside this range, the blendability with polymers a, b, and c will decrease, and the impact resistance of the resin composition will deteriorate. The strength and rigidity decrease.

Further, regarding the polymer e, the unsaturated nitrile as an essential component thereof includes acrylonitrile, methacrylonitrile, etc., and acrylonitrile is particularly preferred, but a copolymer containing methacrylonitrile mainly consisting of acrylonitrile may also be used. Another essential component, aromatic vinyl, is styrene, α-methylstyrene, paramethylstyrene, p-
-chlorostyrene, p-bromostyrene, 2.4.5-
) ribomostyrene, etc., and styrene is most preferred, but a copolymer containing styrene as a main component mixed with other aromatic vinyls mentioned above may also be used. As a component of this polymer e,
One or more monomer components copolymerizable with unsaturated nitrile and aromatic vinyl may be introduced. Polymer a, b
, If it is necessary to further improve the blendability with c or to lower the melt viscosity during blending, use a compound with a carbon number of 1
an alkyl acrylate consisting of ~8 alkyl groups, and
Alternatively, alkyl methacrylates can be used.

In addition, if it is necessary to increase the heat resistance of the resin composition,
The monomer is selected from monomers such as acrylic acid, methacrylic acid, maleic anhydride, and N-substituted maleimide, with N-phenylmaleimide being particularly preferred.

The number of unsaturated 2) IJ units in the composition of polymer e is 10
~40% by weight, aromatic vinyl units from 90 to 60% by weight,
The monomer units that can be copolymerized with these need to be in the range of 0 to 30% by weight; outside this range, the blendability with polymers a, b, and c will decrease, and the impact resistance of the resin composition will deteriorate. The strength and rigidity decrease.

Polymers a and b constituting the resin composition of the present invention.

Regarding the amount ratio of C and the compatibility improver, polymer a is 30
~60 parts by weight, 10 to 50 parts by weight of polymer C, polymer C
is in the range of 5 to 20 parts by weight, and the compatibility improver is in the range of 3 to 20 parts by weight. Here, polymer a is 3
If it is less than 0 parts by weight, flame retardancy will be reduced, and if it exceeds 60 parts by weight, thermal stability and impact resistance will be reduced. In addition, polymer suga 1
If it is less than 0 parts by weight, impact resistance will be poor, and if it exceeds 50 parts by weight, rigidity, fluidity, and heat resistance will be reduced. Furthermore, if the amount of polymer C is less than 5 parts by weight, the impact resistance will be poor, and if it exceeds 20 parts by weight, the rigidity, fluidity, and heat resistance will be reduced.

On the other hand, if the compatibility improver is less than 3 parts by weight, the effect of making polymers a and b compatibilizing will be small and the IS resistance will be poor, and if it exceeds 20 parts by weight, the total amount of polymers a, b, and c will decrease, resulting in difficulty. The balance between flammability, impact resistance, and rigidity becomes unbalanced.

When polymers a, b, c and the compatibility improver are heat-melted and mixed in an extruder, known tin-based heat stabilizers, lubricants such as stearic acid and zinc stearate, and light resistance such as ultraviolet 'a absorbers are used. It is possible to add additives, antioxidants such as BIT, flame retardant aids such as antimony oxide, and colorants.

〔Example〕

The present invention will be specifically described below with reference to Examples and Comparative Examples. The methods for measuring each physical property used in the present invention are as follows.

(1) Tensile strength, tensile elongation It was measured by a method based on ASTM-0638.

(178” test piece) (2) Bending strength, bending modulus ^ Measured by a method based on STM-0790.

(178" test piece) The flexural modulus was used as a measure of the rigidity of the polymer.

(3) Izot impact strength Measured in accordance with ASTM-0256 and used as a measure of impact resistance. (178” test piece V-notch) (4) Thermogravimetric balance test: Using a high-grade thermal analyzer DT-40, under a nitrogen stream,
The temperature was increased at a rate of °C/min and the temperature at which the weight decreased by 5% by weight was taken as a measure of thermal stability.

(5) Vicat softening temperature ^ Measured by a method based on STM-01525 and used as a measure of heat resistance.

(6) Flame retardant VB (Vertical Bur) compliant with UL-94
ning) method. (1/8" test piece) (7) Solvent resistance A 178" test piece was immersed in gasoline at room temperature for 24 hours, and its appearance was observed.

(8) Observation of morphology of resin composition An ultrathin section of 0.5 m square or less is prepared from the resin composition, and the surface is cut and finished using a diamond knife. This sample was immersed in an osmic acid aqueous solution and stained, and the acceleration voltage was 1
Observation was made using a transmission electron microscope at 00 kV.

Reference Example 1 Production of polymer 10 parts by weight of polybutadiene rubber was dissolved in a mixed solution containing 90 parts by weight of styrene and a small amount of chain transfer agent, and the solution was continuously added to a multistage reactor equipped with a stirrer equipped with a devolatilization device. Polymer b- with a rubber content of 12.2% by weight was produced by thermal polymerization
I got 1. Further, according to electron microscope observation, the average rubber particle size was 1.15 μm.

Reference Example 2 Production of Polymer C 70 parts by weight of polybutadiene rubber, 0.05 parts by weight of dihexyl sulfosuccinate, 0.0 parts by weight of ammonium persulfate.
An aqueous emulsion containing 200 parts by weight of ion-exchanged water and 200 parts by weight of ion-exchanged water was charged into a reactor, and the internal temperature was controlled at 75°C. Next, 30 parts by weight of a monomer mixture of 50% by weight of methyl methacrylate and 50% by weight of styrene was added continuously over 2 hours, and after the addition was completed, polymerization was continued for another 2 hours. Polymer c-1 was obtained. The reaction rate was 98%. The weight ratio of methyl methacrylate units to styrene units in this polymer was 50,150. Further, according to electron microscope observation, the average rubber particle diameter was 0.4 μm.

Example 1 Polyvinyl chloride with a degree of polymerization of 700 (manufactured by Shin-Etsu Chemical, trade name: T 700), polymer b-1 of Reference Example 1, and Reference Example 2
Polymer c-1 and methacrylic resin (copolymer of methyl methacrylate and methyl acrylate, weight ratio 98/2) as a compatibility improver were mixed in a weight ratio of 40/40/10/10, and After adding 3 parts by weight of an organotin malate stabilizer, 1 part by weight of an organotin sulfur-containing stabilizer and 1 part by weight of a higher alcohol fatty acid ester as a lubricant to the mixture as a heat stabilizer per 100 parts by weight of polyvinyl chloride. The mixture was extruded at 200° C. using a 20 mmφ twin-screw extruder to produce pellets.

A test piece for evaluation was prepared by hot pressing this pellet using a compression molding machine.

Table 1 shows various measurement results.

When this resin composition was observed using an electron microscope, it was found that polyvinyl chloride and polystyrene were dispersed to a size of 1 μm or less, and rubber particles were also uniformly dispersed.

Moreover, according to Table 1, it can be seen that this resin composition has thermal stability, impact resistance, rigidity, solvent resistance, heat resistance, and flame retardance.

Example 2 The same experiment as in Example 1 was repeated and evaluated except that MS resin (copolymer of methyl methacrylate and styrene, weight ratio 30/70) was used instead of methacrylic resin as the compatibility improver. did.

Table 1 shows various measurement results.

When this resin composition was observed using an electron microscope, it was found to be well dispersed as in Example 1.

Moreover, according to Table 1, it can be seen that this resin composition has thermal stability, impact resistance, rigidity, solvent resistance, heat resistance, and flame retardance.

Example 3 The same experiment as in Example 1 was repeated and evaluated except that AS resin (copolymer of acrylonitrile and styrene, weight ratio 25/75) was used instead of methacrylic resin as a compatibility improver. .

Table 1 shows various measurement results.

When this resin composition was observed using an electron microscope, it was found to be well dispersed as in Example 1.

Moreover, according to Table 1, it can be seen that this resin composition has thermal stabilizer, impact resistance, rigidity, solvent resistance, heat resistance, and flame retardancy.

Comparative Example 1 Polyvinyl chloride used in Example 1 and polymer b of Reference Example 1
-1 and the polymer c-1 of Reference Example 2 in a weight ratio of 40150/
The same experiment as in Example 1 was repeated and evaluated. Table 1 lists the various measurement results.

When this resin composition was observed under an electron microscope, it was found that polyvinyl chloride and polystyrene had phase separated on the order of several micrometers to several tens of micrometers due to the absence of a compatibility improver.

Furthermore, according to Table 1, it can be seen that polymers a, b, and C are inferior in mechanical properties such as Izot impact strength and tensile strength.

Comparative Example 2 Polyvinyl chloride used in Example 1 and Reference Example IC Polymer b
-1 and the methacrylic tree 11i used in Example 1 were mixed at a weight ratio of 40150/10, and the same experiment as in Example 1 was repeated and evaluated. Table 1 shows the results of measurements of famous species.

According to Table 1, the Izod impact strength is low in the system of polymers a and b and the compatibility improver.

Comparative Example 3 Polyvinyl chloride used in Example 1 and Reference Example 2C Polymer c
-1 and the methacrylic catalyst used in Example 1 at a weight ratio of 40
The same experiment as in Example 1 was repeated and evaluated by mixing at a ratio of 150/10. Table 1 shows the results of measurements of famous species.

According to Table 1, it can be seen that the system of polymers a and C and the compatibility improver has low rigidity and heat resistance.

Comparative Example 4 The same experiment as in Example 1 was repeated and evaluated by adding a heat stabilizer and a lubricant to the polyvinyl chloride used in Example 1. Table 1 shows various measurement results.

According to Table 1, it can be seen that the Izot impact strength, heat resistance, and thermal stability are low.

Comparative Example 5 Reference Example 10 Polymer b-1 was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

According to Table 1, it can be seen that the flame retardance and solvent resistance are poor.

(The following is a blank space) [Effects of the Invention] As explained above, the resin composition of the present invention is a flame-retardant and impact-resistant resin composition that has thermal stability during processing, heat resistance, solvent resistance, and rigidity. . This resin composition is used for home appliance parts, O
It is suitable for A-equipment equipment, etc., and plays a large role in industry.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] (1) (A) 30 to 60 parts by weight of a vinyl chloride polymer with an average degree of polymerization of 400 to 1,700; (B) a rubbery polymer with a glass transition point (Tg) of 25°C or lower and an aromatic vinyl compound; Graft polymer 10-50
parts by weight, (C) 5 to 20 parts by weight of a graft copolymer of a rubbery polymer having a glass transition point (Tg) of 25°C or lower, an aromatic vinyl compound, and a methacrylic acid ester, and (D) a compatibility improver. A flame-retardant and impact-resistant resin composition comprising 3 to 20 parts by weight.