JPH0586815B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is a thermoplastic resin with excellent heat resistance and impact resistance, which is made by blending a polyorganosiloxane-based graft copolymer and an α-methylstyrene-acrylonitrile-based copolymer in a specific ratio. Regarding the composition. (Prior art) A method of blending an α-methylstyrene-acrylonitrile copolymer and an ABS resin as a resin composition having high heat resistance and impact resistance is already known, for example, in Japanese Patent Publication No. 18194/1983. be. (Problems to be Solved by the Invention) However, although the resin composition formed by blending such α-methylstyrene-acrylonitrile copolymer with ABS resin has high heat resistance and impact resistance, the rubber of ABS resin Since polybutadiene or butadiene copolymer is used as a source, weather resistance is poor, and outdoor use has been restricted. (Means for Solving the Problems) As a result of intensive studies in view of the above-mentioned points, the present inventors have found that by using polyorganosiloxane rubber instead of polybutadiene or butadiene copolymer, which is the rubber source of the above-mentioned ABS resin, The present inventors have discovered that it is possible to make a thermoplastic heat resistant material with excellent heat resistance and impact resistance without being subject to any restrictions on its use, and have thus arrived at the present invention. That is, in the present invention, in the presence of 1 to 50 parts by weight of a polyorganosiloxane polymer, 60 parts by weight of an aromatic vinyl monomer
~90% by weight, vinyl cyanide monomer 10-40% by weight
50 to 99 parts by weight of a monomer mixture consisting of (total amount 100
10 to 60 parts by weight of graft copolymer (A) obtained by graft polymerization of
and other vinyl monomers copolymerizable with these 0
90 to 40 parts by weight of copolymer (B) obtained by copolymerizing a monomer mixture consisting of ~20% by weight (total amount of (A) and (B))
100 parts by weight). The graft copolymer (A) in the present invention is obtained by graft polymerizing a monomer mixture of an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of a polyorganosiloxane polymer. . It is preferable to first produce a polyorganosiloxane-based polymer by adding a grafting agent to organosiloxane and polymerizing it. By the way, polyorganosiloxanes generally have poor reactivity with vinyl monomers, making it difficult to form chemical bonds. Therefore, although several methods have been proposed for forming a bond between the two components, these methods have not always been satisfactory. US Pat. No. 3,898,300 discloses a method using vinylsiloxane as a graft cross-agent, and US Pat. No. 4,071,577 discloses a method using mercaptosiloxane as a graft cross-agent. As the organosiloxane, for example, hexamethyltrisiloxane, octamethyltetracyclosiloxane, decamethylpentacyclosiloxane, dodecamethylhexacyclosiloxane, trimethyltriphenyltricyclosiloxane, etc. are used. Also, as a grafting agent,

[Chemical Formula] (In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a phenyl group, n is 0, 1 or 2, and p is a number from 1 to 6. ) (Meta)acryloxysiloxane having a unit represented by CH ₂ =CH-SiR ² nO _(3-o)/2 ( ) Vinyl siloxane having a unit represented by (in the formula, R ² and n are the same as above) and HS(-CH ₂ ) _p ---SiR ² nO _(3-o)/2 () (in the formula, R ² and n are the same as above). It is possible, but from the viewpoint of high grafting rate and good fluidity of the polymer, etc. ()
A (meth)acryloxysiloxane represented by the formula is preferred, and a methacryloxysiloxane in which R ¹ in the formula () is a methyl group is particularly preferred. The amount of the graft cross-agent additive is 0.001 to 10 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the organosiloxane. If the amount of the grafting agent added is less than 0.001 part by weight, the grafting ratio will be too small, making it difficult to obtain a good grafting effect. Also, the amount of graft cross-agent added is
If it exceeds 10 parts by weight, the condensation with the organosiloxane will not be successful, making it difficult to obtain a homogeneous polymer. Polyorganosiloxanes are covered by U.S. Patent No.
Produced by the method described in Specification No. 2891920, Specification No. 3294725, etc., that is, a method of shearing and mixing organosiloxane and grafting agent in the presence of an emulsifier such as alkylbenzenesulfonic acid using, for example, a homogenizer. It is preferable to do so. Alkylbenzenesulfonic acid is suitable because it acts as an emulsifier for polyorganosiloxane and also serves as a polymerization initiator. In addition, in such emulsion polymerization of organosiloxane, a trifunctional or tetrafunctional silicon atom can also be included in the polyorganosiloxane.
These polyfunctional silicon atoms act as so-called crosslinking agents, and crosslinked polyorganosiloxanes using them are effective when used as a rubber source for impact-resistant resins. As a specific example,
Examples include trifunctional crosslinking agents such as methyltrimethoxysilane, phenyltrimethoxysilane, and ethyltriethoxysilane, and tetrafunctional crosslinking agents such as tetraethoxysilane. Crosslinking of the polyorganosiloxane is formed by preparing an emulsion using 0.1 to 10 parts by weight of these based on 100 parts by weight of the polyorganosiloxane polymer. Next, the above polyorganosiloxane polymer 1~
A monomer mixture consisting of 60-90% by weight of aromatic vinyl monomers and 10-40% by weight of vinyl cyanide monomers in the presence of 50-99% by weight of vinyl cyanide monomers in the presence of 50-99% by weight, preferably 10-40 parts by weight
parts by weight, preferably 60 to 90 parts by weight (the total amount of the polyorganosiloxane polymer and the monomer mixture
100 parts by weight) to obtain the graft copolymer (A) of the present invention. Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, chlorostyrene, t-butylstyrene, and the like. Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile. Depending on the case, a portion of the aromatic vinyl monomer and vinyl cyanide monomer may be used in place of the alkyl methacrylate and/or alkyl acrylate. The copolymer (B) in the present invention is 40 to 90% by weight of α-methylstyrene and 10 to 60% by weight of acrylonitrile.
and other vinyl monomers copolymerizable with these 0
It is a copolymer of a monomer mixture consisting of ~20% by weight. Other copolymerizable vinyl monomers include methacrylic acid alkyl esters having an alkyl group having 1 to 4 carbon atoms, acrylic acid alkyl esters having an alkyl group having 1 to 8 carbon atoms, etc. When the polymerization amount exceeds 20% by weight, heat resistance and impact resistance tend to decrease. The above-mentioned graft copolymer (A) and copolymer (B) can be produced by a conventional emulsion radical polymerization method, but the method is not limited thereto. Note that in the emulsion polymerization method, monomers are reacted in an aqueous dispersion medium in the presence of a radical initiator. As a radical initiator, potassium persulfate, t-butyl hydroperoxide,
Cumene hydroperoxide, benzoyl peroxide, etc. are used, and can be used in combination with radical initiation aids, reducing agents, etc. The thermoplastic resin composition of the present invention contains 10 to 60 parts by weight of the above-mentioned graft copolymer (A) and 90 to 40 parts by weight of the copolymer (B). The total amount
The desired heat resistance and impact resistance can be obtained by adjusting the blending ratio of each component, but in order to obtain the desired heat resistance and impact resistance, it is necessary to The graft copolymer (A) and the copolymer (B) are preferably blended so that the content of the polyorganosiloxane polymer is 5 to 30% by weight, preferably 15 to 25% by weight. The thermoplastic resin composition of the present invention can be prepared, for example, by mixing the latexes of the graft copolymer (A) and the copolymer (B), salting out, coagulating, and drying to obtain a mixture; Both latexes of polymer (A) and copolymer (B) are individually salted out, coagulated and dried to obtain a powdery polymer, which is then rolled, screwed, etc.
Knead with a Banbury mixer, kneader, etc., or
Alternatively, it can be obtained by pelletizing these powdered polymers and then kneading them by the above method. The thermoplastic resin composition of the present invention may contain stabilizers, pigments, lubricants, etc., if necessary. (Example) The present invention will be specifically described below with reference to Examples. The heat distortion temperature in each example and comparative example is
According to ASTM D-648-56 (load 18.56Kg/cm ² ),
In addition, the notched Izot impact strength at 23℃ is
Each was measured according to ASTM D-256-56. Examples 1 to 8, Comparative Examples 1 to 4 (1) Polyorganosiloxane graft copolymer (A)
Production of ethyl orthosilicate 1.0 parts by weight, γ-methacryloxypropyldimethoxymethylsilane 0.75
parts by weight and 100 parts by weight of octamethyltetracyclosiloxane were mixed, put into 300 parts by weight of distilled water in which 1.0 part by weight of dodecylbenzenesulfonic acid was dissolved, prestirred with a homomixer, and then mixed with a homogenizer at 250 kg/cm ² 2 at the pressure of
It was emulsified and dispersed by passing it through. This mixed solution was transferred to a separable flask equipped with a condenser, a nitrogen inlet, and a stirring blade, and heated at 90° C. for 6 hours while stirring and mixing to complete the polymerization of polydimethylsiloxane. The polymerization rate of the obtained polyorganosiloxane was 91.6%, and the particle size of the polyorganosiloxane polymer measured by turbidity method was 0.13 μm. This polyorganosiloxane latex was neutralized with an aqueous sodium carbonate solution to a pH of 8. 690 parts by weight of distilled water was added to this, and the mixture was transferred to a separable flask equipped with a dropping bottle, a condenser, a nitrogen inlet, and a stirring blade, and the temperature was raised to 75° C. while flowing nitrogen. Next, a mixed monomer mixture of 37.5 parts by weight of acrylonitrile and 112.5 parts by weight of styrene was graft-polymerized. The particle size of the obtained polymer latex is
It was 0.23 μm. 15 parts by weight of this latex
The polymer was separated by pouring it into hot water in which CaCl ₂ .2H ₂ O was dissolved and performing salting out coagulation. After thoroughly washing with water, it was dried at 80°C for 16 hours to obtain a polyorganosiloxane graft copolymer (A). The polymerization rate of the graft monomer was 99.8%. (2) Production of α-methylstyrene copolymer (B) α-methylstyrene, acrylonitrile, and methyl methacrylate were emulsion polymerized in the composition ratios shown in Table 1 using a conventional method to produce various α-methylstyrene copolymers. Polymer (B) was produced.

【table】

[Table] (3) Preparation of resin composition The polyorganosiloxane graft copolymer (A) obtained in (1) above and various α-methylstyrene copolymers (B) obtained in (2) were mixed into a second Test pieces for measuring various physical properties were prepared by melting and kneading the mixture in the proportions shown in the table.
Various physical properties were measured. These results are also shown in Table 2.

【table】

[Table] Example 9 In producing the polyorganosiloxane graft copolymer (A) in (1) of Examples 1 to 8, graft cross-polymer was used instead of γ-methacryloxypropyldimethoxymethylsilane during polymerization of polydimethylsiloxane. Polydimethylsiloxane was produced in the same manner except that 0.75 parts by weight of tetravinyltetramethyltetracyclosiloxane or 0.75 parts by weight of γ-mercaptopropyldimethoxysilane was used as the agent, and then acrylonitrile and styrene were graft-polymerized. Various physical properties of a mixture of 50 parts by weight of the obtained polyorganosiloxane graft copolymer and 50 parts by weight of the above-mentioned α-methylstyrene copolymer (B-2) were measured in the same manner as described above. These results are shown in the third
Shown in the table.

[Table] (Effects of the invention) The thermoplastic resin composition of the present invention has heat resistance, heat resistance, and This results in a resin composition with excellent impact resistance.

Claims (1)

^[ Claims] ^1. Based on 100 parts by weight of organosiloxane, the following formula: (meth)acryloxysiloxane having a unit represented by n is 0, 1 or 2, p is a number from 1 to 6), CH ₂ = CH-SiR ² nO _(3-o)/2 () (formula Vinylsiloxane having a unit represented by HS( _{-CH 2} ⁾ _p ---SiR ² nO _(3-o)/2 () (wherein R ² and n are the same as above) In the presence of 1 to 50 parts by weight of a polyorganosiloxane polymer obtained by adding 0.001 to 10 parts by weight of a grafting agent selected from mercaptosiloxanes having units represented by monomer 60
~90% by weight, vinyl cyanide monomer 10-40% by weight
50 to 99 parts by weight of a monomer mixture consisting of (total amount 100
10 to 60 parts by weight of graft copolymer (A) obtained by graft polymerization of
and other vinyl monomers copolymerizable with these 0
90 to 40 parts by weight of copolymer (B) obtained by copolymerizing a monomer mixture consisting of ~20% by weight (total amount of (A) and (B))
100 parts by weight).