JPH09302242A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin compsn. which can provide a molding having excellent impact resistance, slidability, moldability, water repellency, and lubricity by incorporating a specific silicone-acrylic block/graft copolymer into a thermoplastic resin. SOLUTION: A thermoplastic resin (A) in an amt. of 100 pts.wt. is mixed with 0.5 to 50 pts.wt. block or graft copolymer (B), of an organopolysiloxane with a (meth)acrylic acid polymer, prepd. by radical copolymn. in the presence of a mercapto compd., represented by formula I or II (wherein R<1> represents a 1-12C divalent hydrocarbon group; (k) is 0 to 10; (n) is 1 to 200; and L is 1 to 10), as a chain transfer agent, the content of the organopolysiloxane in the copolymer being 10 to 60wt.%, to obtain a thermoplastic resin compsn.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to impact resistance, slidability,
The present invention relates to a thermoplastic resin composition which gives a molded article excellent in molding processability, water repellency and lubricity. More specifically, it relates to a thermoplastic resin composition obtained by blending a specific organopolysiloxane and a block / graft copolymer of a (meth) acrylic polymer.

[0002]

2. Description of the Related Art Conventionally, by internally adding diorganopolysiloxane to a thermoplastic resin, it has been attempted to impart mold releasability, moldability such as dimensional stability and shortening of molding time, Many attempts have been made to impart functions such as surface lubricity and impact resistance to the obtained molded product. For example, as disclosed in Japanese Patent Laid-Open No. 63-277263, there is disclosed a method in which a dimethylpolysiloxane having a viscosity of 150,000 cSt or more is blended with a thermoplastic resin to obtain a molded article having excellent slidability. ing.

[0003]

However, when dimethylpolysiloxane exceeds 200 ° C., it is thermally decomposed to form a low-molecular-weight siloxane, so that it is kneaded with a thermoplastic resin or molded of a resin composition containing dimethylpolysiloxane. In the meantime, there is a problem in that this is thermally decomposed to deteriorate the appearance of the molded product (decrease in gloss and generation of silver strips) and the strength of the weld line is reduced. In addition, since the above-mentioned dimethylpolysiloxane is generally poor in compatibility with these thermoplastic resins, there is a problem that bleeding out occurs after molding and stickiness remains or stains easily occur. Therefore, for the purpose of improving the bleed-out property, there has been proposed a resin composition which is grafted with an organopolysiloxane on an acrylic polymer and has sufficient lubricity and water repellency without stickiness (JP-A-2-58667). 5-311054). However, when an organopolysiloxane-grafted acrylic polymer is kneaded with a low-melting resin such as polyolefin or vinyl chloride resin, it can be kneaded without thermal decomposition, but when kneaded with a high-melting resin such as a polyester resin or a polycarbonate resin. Has a problem that it is thermally decomposed to deteriorate the appearance of the molded product, and excellent slidability does not last for a long time.

Further, polytetrafluoroethylene powder is also widely used as a material which is not thermally decomposed during kneading or molding and is provided with slidability, but such a halogen compound is molded by containing it. When a product is incinerated as waste, it produces hydrofluoric acid, so it is currently being used like an organic halogen-based flame retardant.

[0005]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to solve the above-mentioned problems, and as a result, do not cause thermal decomposition even if the kneading temperature or molding temperature of the composition is high.
We have discovered a thermoplastic resin composition in which a silicone acrylic block or graft copolymer is blended with a thermoplastic resin. By using this resin composition, it is possible to provide a molded article having excellent impact resistance, slidability, moldability, water repellency and lubricity.

That is, according to the present invention, 100 parts by weight of a thermoplastic resin and 0.5 to 50 parts by weight of a block or graft copolymer of an organopolysiloxane and a (meth) acrylic polymer obtained by radical polymerization using a mercapto compound as a chain transfer agent. A thermoplastic resin composition having a high melting temperature because the organopolysiloxane of the present invention and the block or graft copolymer of the (meth) acrylic polymer have a high thermal decomposition initiation temperature. It is suitable for a composition with

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As the thermoplastic resin used in the present invention, a polyolefin resin such as polyethylene or polypropylene; a vinyl chloride resin; polystyrene, AS, A
Styrene resin such as BS; Polyester resin such as polyethylene terephthalate and polybutylene terephthalate; Polycarbonate resin; Polyether resin such as polyoxymethylene and polyoxyphenylene; Nylon 6,
Polyamide resins such as nylon 6,6, nylon 6,10 and polyhexamethylene terephthalamide; polyarylene sulfide resins and the like are exemplified, and particularly polyester resins, polycarbonate resins, polyether resins, polyarylene sulfide resins, polyamide resins, etc. The high melting point resin of is suitable.

Next, the silicone / acrylic block / graft copolymer blended with the thermoplastic resin in the present invention is obtained by radical polymerization using a mercapto compound as a chain transfer agent. It is different from polymers and silicone-grafted acrylic resins. That is, since the terminal group of the silicone / acrylic block / graft copolymer compounded in the present invention is terminated by a sulfide bond, an unsaturated group or radical initiator residue formed by conventional radical polymerization is terminated. Since it is different from the terminal, the resulting thermoplastic resin composition has extremely high heat resistance.

Further, since the copolymer of the present invention has a relatively low molecular weight and excellent fluidity at high temperature, it is easy to knead when it is made into a composition, and it is easy to handle because it is solid at room temperature. Also, the composition has no sticky feeling even after molding and can be used as a solid lubricant.

The organopolysiloxane of the present invention can be obtained by radical copolymerization in the presence of the following various mercapto compounds. That is, copolymers and general formulas of alkyl mercaptans such as decyl mercaptan and dodecyl mercaptan with radically polymerizable unsaturated group-containing dimethylpolysiloxane and other radically polymerizable monomers

Embedded image (In the formula, R ¹ is a divalent hydrocarbon group having 1 to 12 carbon atoms, and k is 0.
Is an integer from 1 to 10, and n is an integer from 1 to 200. In all the chemical formulas below, Me represents a methyl group and nBu represents an n-butyl group), a copolymer of dimethylpolysiloxane and another radically polymerizable monomer, and further, a general formula

Embedded image A copolymer of dimethylpolysiloxane represented by the formula (wherein R ¹ and n are the same as above, L is an integer of 1 to 10) and another radically polymerizable monomer is used.

Specific examples of the radical-polymerizable unsaturated group-containing dimethylpolysiloxane used in the present invention include the following, but the invention is not limited thereto.

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[Chemical 6]

[Chemical 7]

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[Chemical 12]

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In the present invention, a part of a plurality of methyl groups bonded to Si atoms in dimethylpolysiloxane is n-.
Propyl group, phenyl group, n-hexyl group, 3,3,3
-Although it may be substituted with a trifluoropropyl group or the like, the methyl group content is preferably 50 mol% or more in order to sufficiently impart the characteristics to the thermoplastic resin composition of the present invention. The molecular weight of dimethylpolysiloxane in the present invention is preferably from 500 to 20,000, and when it is less than 500, the characteristics of the thermoplastic resin composition of the present invention cannot be obtained,
When it exceeds 20,000, thermal decomposition of dimethylpolysiloxane occurs, which is not preferable. Radical polymerizable monomers copolymerizable with these dimethylpolysiloxanes include methyl (meth) acrylate, ethyl (meth) acrylate,
Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, perfluorobutyl (meth) acrylate, trifluoropropyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, (Meth) acrylic acid esters such as benzyl (meth) acrylate; styrene, α-methylstyrene, p-tert-
Butylstyrene and other styrenes; vinyl acetate; (meth)
Acrylonitrile, N, N-dimethylacrylamide,
N, N-dimethylaminopropylacrylamide, N,
Acrylamides such as N-diethylacrylamide; diethyl maleate, dibutyl fumarate, dibutyl itaconate and vinylpyrrolidone, 3-meth (acrylic acid) -3-tris (trimethylsilyloxy) silylpropyl, (meth) acrylic acid-3-bis ( (Trimethylsilyloxy)
Examples include methylsilylpropyl and 3- (meth) acryloxypropyltrimethoxysilane. Methyl methacrylate and styrene are particularly preferable.

The following are specific examples of the mercapto group-containing organopolysiloxane represented by (Chemical Formula 1) and (Chemical Formula 2).

[Chemical 21]

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[Chemical formula 26]

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[Chemical 29]

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[Chemical 31]

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[Chemical 33]

In the above-mentioned mercapto group-containing organopolysiloxane, a part of a plurality of methyl groups bonded to Si atoms is n-propyl group, phenyl group, n-hexyl group, 3,3,3 as in the case of dimethylpolysiloxane. -Although it may be substituted with a trifluoropropyl group or the like, the methyl group content is preferably 50 mol% or more for the same reason. Examples of R ¹ in (Chemical Formula 1) and (Chemical Formula 2) include a methylene group, a propylene group, a butylene group, an isobutylene group, a phenylene group and the like, and a propylene group is industrially widely used. In addition, k is an integer of 0 to 10 is preferable, and if it exceeds 10, the grafted portion becomes too much and the resin becomes hard and brittle.
Poor fluidity at high temperature is not preferable. n is preferably an integer of 1 to 200, and if it exceeds 200, the molecular weight of the block copolymer becomes too large, it does not liquefy even at high temperature, and the kneading property becomes poor. L is also preferably 1 to 10,
If it exceeds, it is not preferable for the same reason as in the case of k.

The content of the organopolysiloxane in the block / graft copolymer of the organopolysiloxane and the (meth) acrylic polymer is preferably 10 to 60% by weight, and when it is less than 10% by weight, sufficient water repellency and lubricity are obtained. It cannot be expected, and if it exceeds 60% by weight, the copolymer becomes sticky and economically disadvantageous.

Copolymer of organopolysiloxane and (meth) acrylic polymer in the present invention [hereinafter, referred to as silicone / (meth) acrylic polymer copolymer]
Are represented by the following general formulas (Formula 34) to (Formula 40), but are not limited thereto.

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Embedded image (In the formula, R ² is a monovalent hydrocarbon group having 4 to 20 carbon atoms, R ³ is hydrogen or a methyl group, R ⁵ is a methyl group or a butyl group, X is COOCH ₃ , COOC ₂ H ₅ , COOC ₄ H ₉ , P is an integer of 5 to 200, and x is a value such that the value of this portion is 40 to 90% by weight with respect to the copolymer, y
Indicates the value at which this portion is 10 to 60% by weight based on the copolymer. )

Embedded image [In the formula, n is an integer of 1 to 200, R ¹ is a divalent hydrocarbon group having 1 to 12 carbon atoms, R ³ is hydrogen or a methyl group, X is the same as above, (x ₁ + x ₂ ) is The total value of the parts is 40 to 90% by weight based on the copolymer. ]

Embedded image [In the formula, (x ₁ + x ₂ + x ₃ ) represents a value such that the total value of this portion is 40 to 90% by weight with respect to the copolymer, and all other symbols are the same as above. ]

Embedded image [In the formula, x represents a value such that the value of this portion is 40 to 90% by weight with respect to the copolymer. All other symbols are the same as above. ]

Embedded image [Wherein (x ₁ + x ₂ ) represents a value such that the total value of this part is 40 to 90% by weight with respect to the copolymer, and (y ₁ + y ₂ ) and both ends of mercaptoalkyldimethylpolysiloxane The total value is 10 to 60% by weight based on the copolymer. All other symbols are the same as above. ]

Embedded image [All symbols in the formula are the same as above. ]

The copolymerization reaction in the present invention includes benzoyl peroxide for both graft copolymerization and block copolymerization.
Organic peroxides such as dicumyl peroxide and lauroyl peroxide; normal azo compounds such as 2,2′-azobis (2-methylbutyronitrile) and 2,2′-azobisisobutyronitrile The polymerization is carried out in the presence of a radical polymerization initiator, and any one of solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization can be applied. Further, during polymerization, since a mercapto compound is used as a molecular weight modifier, it is controlled to some extent, but carbon tetrachloride, α-methylstyrene dimer, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, etc. You may use together.

In the present invention, the solution polymerization method among these polymerization methods is particularly preferable because it is easy to adjust the molecular weight of the obtained silicone / (meth) acrylic polymer copolymer to the optimum range. . As the solvent used in this case, aromatic hydrocarbons such as benzene, toluene, xylene; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; ethyl acetate, acetic acid n-
Butyl, isobutyl acetate and other esters; ethanol,
Examples thereof include one kind or a mixture of two or more kinds selected from alcohols such as isopropanol, n-butanol and isobutanol. Polymerization temperature is 50 ~ 180 ℃, especially
The temperature is preferably in the range of 60 to 120 ° C. Under this temperature condition, the polymerization reaction can be completed in about 5 to 10 hours. The method of taking out the copolymer from the copolymerization solution is not particularly limited, but examples thereof include a method of evaporating a solvent, a method of adding a poor solvent such as water and methanol to the copolymerization solution, and precipitating and drying the copolymer. .

The silicone / (meth) acrylic polymer copolymer used in the present invention has a polystyrene-equivalent weight average molecular weight of 2,000 to 100,000, as determined by GPC.
It is preferably in the range of 3,000 to 50,000. If the weight average molecular weight is less than 2,000, slidability and lubricity will be poor,
If it exceeds 100,000, the fluidity becomes poor even during heating and the moldability becomes poor. The thermoplastic resin composition of the present invention preferably contains 0.5 to 50 parts by weight of a copolymer of a silicone / (meth) acrylic polymer, and particularly 1 to 30 parts by weight, based on 100 parts by weight of the thermoplastic resin. It is suitable. Blending amount of silicone / (meth) acrylic copolymer is 0.5
If it is less than 50 parts by weight, long-term wear resistance properties and excellent workability cannot be obtained, and if it exceeds 50 parts by weight, mechanical strength and the like are remarkably reduced.

In the composition of the present invention, for the purpose of further improving slidability, a silicone oil having a high phenyl group content, a side chain mercapto-modified silicone oil, a silicone oil such as metallosiloxane such as cerium or titanium is blended,
Solid lubricants such as graphite, molybdenum disulfide and metallic soap, polytetrafluoroethylene powder, etc. can also be added. Further, additives such as an antioxidant, a heat stabilizer, a weather resistance-imparting agent, a flame retardant, a coloring agent and an antistatic agent may be blended depending on the purpose. Further, for example, a fibrous, plate-like, or granular inorganic filler such as glass fiber can be appropriately added.

The composition of the present invention may be prepared, for example, by kneading with a hot roll, Banbury mixer, heat kneader, etc., and then pelletizing with a uniaxial or biaxial extruder. Then, it is molded by pressing, injection or the like. Also, make a silicone / (meth) acrylic polymer copolymer at a high concentration (for example, 30 to 50% by weight), make a masterbatch, and add it to a molding machine so that a predetermined amount of the mixture is obtained, and then mold it. Is also possible.

[0022]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. All parts in the examples are parts by weight. (Synthesis Example 1) 30 parts of an organopolysiloxane represented by the following formula (Formula 41),

Embedded image 70 parts of MMA, 100 parts of toluene, and 1 part of α, α'-azobis (isobutyronitrile) were placed in a 500-ml glass flask equipped with a stirrer, cooling tube, and thermometer. Polymerization reaction was carried out for a time. After completion of the polymerization, the polymerization solution was stripped under the condition of 150 ° C / 10 mmHg, and the obtained reaction product was cooled and pulverized to obtain a copolymer A.
I got As a result of the measurement of this product by TG-DTA (thermal balance), the heating loss in air at 25 to 300 ° C is
It was 3.2% by weight, the softening point was 115 ° C, and the viscosity at 150 ° C was 25,000 cP.

(Synthesis Example 2) 50 parts of an organopolysiloxane represented by the following formula (Formula 42),

Embedded image 48 parts of MMA, 2 parts of dodecyl mercaptan, and 1 part of α, α′-azobis (isobutyronitrile) were placed in the same glass flask as in Synthesis Example 1, and the polymerization reaction was carried out for 8 hours under aeration of nitrogen. After completion of the polymerization, the same post-treatment as in Synthesis Example 1 was carried out to obtain a copolymer B. The loss on heating of this product in air at 25 to 300 ° C was 4.5% by weight, and the softening point was 104 ° C.
The viscosity at 150 ° C was 3,900 cP.

(Synthesis Example 3) 5 parts of the organopolysiloxane represented by the following formula (formula 43) and 35 parts of the organopolysiloxane represented by the following formula (formula 44),

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Embedded image 60 parts of MMA, 100 parts of toluene, and 1 part of α, α′-azobis (isobutyronitrile) were charged in the same glass flask as in Synthesis Example 1, and the polymerization reaction was carried out for 5 hours under aeration of nitrogen.
After completion of the polymerization, copolymer C was subjected to the same post-treatment as in Synthesis Example 1.
I got The loss on heating of this product in air at 25 to 300 ° C was 2.8% by weight, and the viscosity at a softening point of 102 ° C and 150 ° C was 3,400 cP.

Synthesis Example 4 The following formula (Formula 45)

Embedded image Polymeric initiator represented by MAI-001 (Wako Pure Chemical Industries, trade name, n = approx. 7 in the formula) 30 parts, MMA 70 parts, toluene 100 parts 500 ml capacity equipped with stirrer, cooling tube, thermometer Into a glass flask at 90 ° C, nitrogen aeration, 90 ° C, 7
The polymerization reaction was carried out for a time. After the polymerization, post-treatment was carried out according to Synthesis Example 1 to obtain a copolymer D. The weight loss on heating of this product in air at 25 to 300 ° C was 18.1% by weight. The softening point was 138 ° C, and even when heated to 150 ° C, the fluidity was poor and viscosity measurement was difficult.

(Examples and Comparative Examples) Each of the copolymers A to D obtained in the above Synthesis Example and dimethylpolysiloxane oil / KF
-96 [Shin-Etsu Chemical Co., Ltd. product name, viscosity 100,000 cS]
In the ratio shown in Table 1, polybutylene terephthalate resin / Duranex 2000 [trade name of Polyplastics Co., Ltd.] was blended with the Laboplast mill [Co., Ltd.].
Manufactured by Toyo Seiki Seisakusho, Ltd.] and kneaded at 235 ° C. for 10 minutes and then extruded to prepare a pelletized composition. Then, a test piece was prepared by injection molding (240 ° C.) using this pellet, and evaluated by the following various tests. The evaluation results are also shown in Table 1. The tensile strength is ASTM
According to the measuring method of No. 1, the dynamic friction characteristics and the friction noise characteristics were measured by the following methods. <Dynamic friction characteristics> Using a HEIDON-14 type friction tester manufactured by Shinto Kagaku Co., Ltd., the friction element is a stainless steel ball, a load of 20 g, and a linear velocity of 1,500 mm / min. <Frictional sound characteristics> Using a Suzuki-type friction and wear tester, pressure 3.5
After the materials of the same kind were slid for 10 hours at kg / cm ² , a linear velocity of 50 mm / min, and a contact area of 2.0 cm ² , the squeak noise generation state was examined. The moldability was evaluated according to the following criteria. Good ……… Easily removable from the injection molding machine. Somewhat bad ... Sometimes it takes a little air pressure to take it out of the injection molding machine.

[0027]

[Table 1]

[0028]

By using the resin composition of the present invention, it is possible to provide a molded article having excellent impact resistance, slidability, moldability, water repellency and lubricity.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 69/00 LPT C08L 69/00 LPT 71/12 LQP 71/12 LQP 77/00 LQR 77/00 LQR 81/02 LRG 81/02 LRG 83/08 LRY 83/08 LRY

Claims (5)

[Claims] 1. A blend of 100 parts by weight of a thermoplastic resin and 0.5 to 50 parts by weight of a block or graft copolymer of an organopolysiloxane and a (meth) acrylic polymer obtained by radical copolymerization using a mercapto compound as a chain transfer agent. A thermoplastic resin composition obtained by 2. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin is a polyester resin, a polycarbonate resin, a polyether resin, a polyarylene sulfide resin or a polyamide resin. 3. A mercapto compound is represented by the following general formula: (In the formula, R ¹ is a divalent hydrocarbon group having 1 to 12 carbon atoms, and k is 0.
The thermoplastic resin composition according to claim 1, wherein n is an integer of 1 to 200, n is an integer of 1 to 200, and Me is a methyl group. 4. A mercapto compound is represented by the following general formula: The thermoplastic resin composition according to claim 1, wherein R ¹ and n are the same as those in the preceding paragraph, L represents an integer of 1 to 10, and Me represents a methyl group. 5. The thermoplastic resin composition according to claim 1, wherein the content of the organopolysiloxane in the block or graft copolymer of the organopolysiloxane and the (meth) acrylic polymer is 10 to 60% by weight. .