JPH0959452A - Polypropylene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polypropylene resin compsn. which has a high stiffness and is excellent in impact resistance, elongation, and the balance among physical properties. SOLUTION: This compsn. comprises 70-90wt.% polypropylene, 5-20wt.% polystyrene-ethylene/propylene-polystyrene triblock copolymer (A) having a styrene content of 15-40wt.%, 5-20wt.% polystyrene-ethylene/butene-polystyrene triblock copolymer (B) having a styrene content of 15-40wt.%, and 1-3wt.% polyethylene-ethylene/butene-polyethylene triblock copolymer (C), the wt. ratio of triblock copolymer A to the sum of the triblock copolymers A and B being 0.2 to 0.8.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polypropylene resin composition which is excellent in impact resistance and rigidity and is suitable as a material for home electric appliances and the like.

[0002]

2. Description of the Related Art Polypropylene resin compositions having excellent impact resistance and rigidity have hitherto been known as polypropylene homopolymers, propylene block copolymers, propylene random copolymers and the like, and polypropylene-ethylene rubber. Blends, polypropylene and ethylene
Examples include blend polymers of propylene rubber and ethylene-butene rubber.

[0003]

However, a material composed of a blended polymer of polypropylene and ethylene-propylene rubber has sufficient impact resistance but insufficient elongation and rigidity, while polypropylene and ethylene-propylene rubber Although the material composed of the blend polymer with ethylene-butene rubber has improved elongation and rigidity, it has a drawback of low impact resistance at low temperature.

The present invention has been made to solve these problems, and provides a polypropylene resin composition having high rigidity, excellent impact resistance and elongation, and having an excellent balance of physical properties. Is.

[0005]

Means for Solving the Problems The above-mentioned problems are addressed by the following: (A) Polypropylene-70 to 90% by weight and (B) Styrene content of 15 to 40% by weight polystyrene-ethylene / propylene-polystyrene triblock copolymer 5 to 20
5% to 20% by weight of (C) polystyrene-ethylene / butene-polystyrene triblock copolymer having a styrene content of 15 to 40% by weight, and (D) polyethylene-ethylene / butene-polyethylene triblock copolymer 1 to 3% by weight of the polymer, and the polystyrene-ethylene / propylene-polystyrene triblock copolymer component (B) and the polystyrene-ethylene / butene-
The ratio of the polystyrene-ethylene / propylene-polystyrene triblock copolymer component (B) to the total amount of the polystyrene triblock copolymer component (C) is 20 to.
It can be solved by a polypropylene resin composition of 80% by weight.

Hereinafter, the present invention will be described in detail. (A) Polypropylene As the polypropylene used in the present invention, any one of a propylene homopolymer (homopolypropylene), a block copolymer, a random copolymer, or a combination of two or more thereof may be used. it can.
As the comonomer of the block copolymer or the random copolymer, α-olefins other than propylene such as ethylene, butene-1, pentene-1, and hexene-1 are used, and among them, ethylene is particularly preferable. The propylene content in these copolymers is preferably 60 to 100 mol%, particularly preferably 80 to 99 mol%. In the block copolymer using ethylene as the α-olefin, the ethylene-propylene block in the molecule is dispersed in the homopolypropylene block and exhibits rubber elasticity, and functions as a rubber component. The content of the rubber component is preferably 10 to 25% by weight of the block copolymer.

Melt flow rate of polypropylene (J
It is preferably 5 to 500 g / 10 minutes, as measured by IS K6758 and hereinafter sometimes referred to as MFR). MFR
Is less than 5 g / 10 minutes, the fluidity of the obtained resin composition is poor and the moldability is deteriorated. If the MFR exceeds 500 g / 10 minutes, the impact resistance of the resin composition will be poor. These polypropylenes may be those having a low MFR within the above range by kneading and bisbreaking with an organic peroxide. Further, two or more kinds of polypropylenes having different fluidity may be mixed and the MFR may be within the above range.

(B) Polystyrene-ethylene / propylene-polystyrene triblock copolymer (hereinafter referred to as "SE
The polystyrene-ethylene / propylene-polystyrene triblock copolymer used in the present invention has an ethylene / propylene alternating copolymer block located at the center of the molecule, and is located on both sides of the block. This is where the polystyrene block is located. The content of the polystyrene block in this SEPS is preferably 15 to 40% by weight. When the content of the polystyrene block is less than 15% by weight, the rigidity and surface hardness of the obtained propylene-based resin composition decrease, and when it exceeds 40% by weight, the low temperature impact resistance of the propylene-based resin composition decreases.

The flowability of SEPS is preferably such that the MFR at 230 ° C. and 66 psi is 0.5 to 70 g / 10 minutes. MFR
If less than 0.5 g / 10 min, dispersion failure occurs and low temperature impact resistance lowers, and if MFR exceeds 70 g / 10 min, elastic modulus and elongation decrease. SEPS can be produced by hydrogenating a copolymer of styrene and isoprene. For this, styrene, isoprene, a method of hydrogenating after polymerizing styrene and a styrene-isoprene diblock copolymer are first produced,
There are a method of hydrogenating after forming a triblock copolymer by using a coupling agent and a method of directly polymerizing the triblock copolymer by using a bifunctional initiator and then hydrogenating. In any case, a diblock copolymer will be produced, but this proportion is preferably less than 40% by weight of the whole. This is because if it exceeds 40% by weight, the rigidity and the surface hardness decrease.

(C) Polystyrene-ethylene / butene-
Polystyrene triblock copolymer (hereinafter referred to as "SEB
Sometimes referred to as "S") Polystyrene used in the present invention-ethylene / butene-
The polystyrene triblock copolymer is a block in which an ethylene / butene alternating copolymer block is located in the center of the molecule and polystyrene blocks are located on both sides of the block. The content of polystyrene block in SEBS is 1
It is preferably 5 to 40% by weight. When the content of the polystyrene block is less than 15% by weight, the rigidity and surface hardness of the obtained propylene resin composition are lowered,
When it exceeds 40% by weight, the low temperature impact resistance of the propylene resin composition is lowered. Also, SEBS fluidity is 230 ° C.
A MFR at 66 psi of 0.5 to 70 g / 10 min is preferred. This is because if the MFR is less than 0.5 g / 10 minutes, poor dispersion will occur and the low-temperature impact resistance will be deteriorated, and if the MFR exceeds 70 g / 10 minutes, the elastic modulus and elongation will decrease.

SEBS can be produced by hydrogenating a triblock copolymer of styrene and butadiene. For this, a method in which styrene, butadiene, and styrene are sequentially polymerized and then hydrogenated, and a styrene-butadiene diblock copolymer is first produced, and a coupling agent is used to form a triblock copolymer. There is a method of hydrogenating afterwards and a method of directly polymerizing the triblock copolymer by using a bifunctional initiator and then hydrogenating. In any case, a diblock copolymer will be produced, but this proportion is preferably less than 40% by weight of the whole. This is because if it exceeds 40% by weight, the rigidity and the surface hardness decrease.

(D) Polyethylene-ethylene / butene-
Polyethylene triblock copolymer (hereinafter referred to as "CEB
It may be referred to as "C") Polyethylene-ethylene / butene-used in the present invention
The polyethylene triblock copolymer has an ethylene / butene alternating copolymer block located at the center of the molecule, and crystalline polyethylene blocks located on both sides of the block. The content of polyethylene block in CEBC is preferably 15 to 40% by weight. When the content of the polystyrene block is less than 15% by weight, rigidity, heat resistance and surface hardness of the obtained propylene resin composition are lowered, and when it exceeds 40% by weight, low temperature impact resistance of the propylene resin composition is low. descend. Also, the CEBC fluidity is 0.5 to 70 g / 10 in MFR at 230 ° C and 66 psi.
Minutes are preferred. If the MFR is less than 0.5g / 10 minutes,
This is because poor dispersion causes deterioration in low temperature impact resistance, and when MFR exceeds 70 g / 10 minutes, elastic modulus and elongation decrease.

CEBC can be produced by hydrogenating a triblock copolymer of 1,4-polymerized polybutadiene and 1,2-polymerized polybutadiene. For this, there is a method in which a diblock copolymer of butadiene is first produced, a triblock copolymer is formed using a coupling agent, and then hydrogenated. In this case, a diblock copolymer will be produced, but this proportion is preferably less than 40% by weight of the whole. This is because if it exceeds 40% by weight, it will dissolve in PP and the rigidity and surface hardness will decrease.

(Composition ratio) The ratio of the component (A) in the polypropylene resin composition of the present invention is 70 to 90.
% By weight. If the proportion of the component (A) is less than 70% by weight, the heat resistance will decrease, and if it exceeds 90% by weight, the impact resistance will decrease. On the other hand, the proportion of the component (B) in the polypropylene resin composition of the present invention is 5 to 20% by weight. When the composition ratio of the component (B) in the resin composition is less than 5% by weight, the low temperature impact resistance and surface hardness of the obtained polypropylene resin composition are lowered, and when it exceeds 20% by weight, the elongation is lowered. Similarly, the proportion of the component (C) in the polypropylene resin composition of the present invention is 5 to 20% by weight. When the composition ratio of the component (C) in the resin composition is less than 5% by weight, the elongation of the obtained polypropylene resin composition is lowered, and when it exceeds 20% by weight, the low temperature impact resistance and the surface hardness are lowered. Furthermore, the proportion of the component (D) in the polypropylene resin composition of the present invention is 1 to 3.
% By weight. If the composition ratio of the component (D) in the resin composition is less than 1% by weight, the effect of improving the tensile elongation of the obtained polypropylene resin composition is small, and if it exceeds 3% by weight, the rigidity and the surface hardness decrease.

Further, the ratio of the component (B) to the total amount of the component (B) and the component (C) needs to be 20 to 80% by weight. More preferably, it is 30 to 70% by weight. More preferably, it is 35 to 65% by weight.
When the proportion of the component (B) is less than 20% by weight, SEPS
The synergistic improvement in impact resistance does not appear due to the combined use of SEBS and SEBS.

(Method for producing propylene-based resin composition) In producing the propylene-based resin composition of the present invention, a stabilizer, flame retardant against heat, oxygen and light, which is widely used in the field of synthetic resins and synthetic rubbers. ,filler,
Additives such as a colorant, a lubricant, a plasticizer and an antistatic agent may be added depending on the purpose of use within a range that does not essentially impair the characteristics of the polypropylene resin composition of the present invention.

Examples of the antioxidant include the following. Dibutyl hydroxytoluene, alkylated phenol, 4,4'-thiobis- (6-t-butyl-3-methylphenol), 4,4'-butylidenebis- (6-t-butyl-3-methylphenol), 2, 2'-methylenebis- (4-
Methyl-6-t-butylphenol), 2,2'-methylenebis- (4-methyl-6-t-butylphenol), 2,2'-methylenebis- (4-ethyl-6-t-butylphenol), 2,6
-Di-t-butyl-4-ethylphenol, 1,1,3-tris
(2-Methyl-4-hydroxy-5-t-butylphenyl) butane, n-octadecyl-3- (4-hydroxy-3,5-di-t-
Butylphenyl) propionate, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl)]
Propionate] Methane, dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiopropionate. Further, as the hindered phenol type, triethylene glycol-bis [3-
(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,3
5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3, 5-triazine, pentaerythrityl-tetrakis [3- (3,5-di-t
-Butyl-4-hydroxyphenyl) propionate],
2,2-Thio-diethylenebis [3- (3,5-di-t-butyl-
4-Hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-
t-Butyl-4-hydroxy-hydrocinnamamide), 3,5
-Di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-
Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5, -di-t-butyl-4-hydroxybenzyl) -isocyanurate, octylated diphenylamine, 2,4 -Bis [(octylthio) methyl] -O-cresol. Further, as the hydrazine type, N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl)
Propionyl] hydrazine and the like. Besides, a phenol-based antioxidant, a phosphite-based antioxidant, a thioether-based antioxidant, a heavy metal deactivator, etc. can be applied.

Examples of the ultraviolet absorber include 2 (2'-
Hydroxy-5'-methylphenyl) benzotriazole,
2 (2'-hydroxy-3'-t-butyl-5'-methylphenyl) 5chlorobenzotriazole, 2 (2'-hydroxy-
3 ', 5-di-t-butylphenyl) 5chlorobenzotriazole, 2-hydroxy-4-n-octoxybenzophenone, phenyl salicylate, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [ 2-hydroxy-
3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-
Benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2 -(3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5
-Di-t-amyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl)
Examples include benzotriazole and hydroxyphenyl benzotriazole derivatives. Or dimethyl succinate
1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6
-Tetramethylpiperidine polycondensate, poly [{6- (1,
1,3,3-Tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-
Hyperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], N, N'-bis
(3-Aminopropyl) ethylenediamine ・ 2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4piperidyl) amino] -6-chloro-1,3,5-triazine Condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis ( 1,2,2,6,6-pentamethyl-4-piperidyl), 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate and the like.

The following can be applied as the flame retardant. Polybromodiphenyl oxide, tetrabromobisphenol A, brominated epoxy hexabromocyclododecane, ethylenebistetrabrimophthalimide, brominated polystyrene dechlorane, brominated polycarbonate, polyphosphonate compound, halogenated polyphosphonate, triazine, red phosphorus, Tricresyl phosphate, triphenyl phosphate, cresyl diphenyl phosphate, triallyl phosphate, trixylyl phosphate, trialkyl phosphate, trischloroethyl phosphate, trischloropropyl phosphate, tris (dichloropropyl phosphate), antimony trioxide, aluminum hydroxide, Magnesium hydroxide. Alternatively, silicone oil, stearic acid, calcium stearate, magnesium stearate, carbon black, titanium dioxide, silica, mica, montmorillonite and the like.

The propylene resin composition of the present invention can be produced by uniformly blending the components (A), (B), (C) and (D) and the additives. The method of mixing (mixing method) is not particularly limited, and a method generally used in the field of synthetic resins may be applied. As a mixing method, generally used is a method of dry blending using a mixer such as a Henschel mixer, a tumbler and a ribbon mixer, and a melting method such as an open roll, an extrusion mixer, a kneader and a Banbury mixer. There is a method of mixing. Of these methods, two or more of these mixing methods may be used in combination to obtain a more uniform resin composition (for example, after dry-blending in advance, the mixture is melt-mixed). Even when using dry blending together, even when using one or two or more methods of melt-mixing, in producing a molded article by the molding method described below, it is particularly preferable to use pelletizing by manufacturing pellets. .

Among the above-mentioned mixing methods, it is necessary to carry out at a temperature at which the resin used is melted, regardless of whether they are melt-mixed or molded by the molding method described later. However, if it is carried out at a high temperature, the resin is thermally decomposed or deteriorated, so that it is generally carried out at 170 to 350 ° C, preferably 180 to 260 ° C.

The polypropylene resin composition of the present invention is molded into a desired shape by applying a molding method such as an injection molding method, an extrusion molding method, a compression molding method or a hollow molding method which is generally practiced in the field of synthetic resins. You may let me. Alternatively, after being formed into a sheet using an extrusion molding machine, this sheet may be formed into a desired shape by a secondary processing method such as a vacuum forming method or a pressure forming method.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on Examples, but it goes without saying that these Examples do not limit the present invention.

[0024]

EXAMPLES In the following Examples and Comparative Examples, each physical property was measured by the following methods. Izod impact strength (unit: kgf · cm / cm) conforms to ASTM D265,
It was measured with a notch at room temperature and a temperature of -30 ° C. Flexural modulus (unit: kgf / cm ² ) is ASTM D
According to 790, it was measured at a temperature of 23 ° C. Tensile elongation (%) was measured at a temperature of 23 ° C. according to ASTM D638.

The types and physical properties of the components (A), (B), (C) and (D) used in Examples and Comparative Examples are as follows. (A) Polypropylene As polypropylene (PP-1), MFR manufactured by Showa Denko KK is 30 g / 10 minutes and homotype polypropylene “MA810B” (PP-2) is manufactured, and MFR manufactured by the same company is 40 g / min. A block type polypropylene "MK711H" having a rubber content of 15% by weight for 10 minutes was used.

As the polystyrene-ethylene / propylene-polystyrene triblock copolymer (SEPS) (B), two kinds shown in Table 1 were used.

[Table 1]

(C) Polystyrene-ethylene / butene-
The polystyrene triblock copolymer (SEBS) is shown in Table 2.
Two types were used.

[Table 2]

(D) Polyethylene-ethylene / butene-
Table 3 shows polyethylene triblock copolymer (CEBC).
Two types were used.

[Table 3]

For comparison, instead of the triblock copolymer (TBC), ethylene / propylene rubber (intrinsic viscosity [η] = 2.5 dl / g, propylene content 25% by weight, hereinafter referred to as EPR), ethylene / butene rubber (Intrinsic viscosity [η] = 3.5 dl / g, butene content 15% by weight,
Hereinafter referred to as EBR).

Each of these components was blended in the proportions shown in Table 4 and dry blended for 5 minutes with a Henschel mixer. The obtained mixture was continuously mixed using a same-direction twin-screw extruder (diameter 30 mm) set at 180 ° C. to produce pellets. The pellets were injection molded using an injection molding machine set at 200 ° C. to prepare test pieces for measurement. Table 4 shows the results of Izod impact test, flexural modulus and tensile elongation of each test piece.

[0031]

[Table 4]

From Table 4, Examples 1 to 5 corresponding to the present invention
It can be seen that each of them has excellent impact resistance, rigidity and tensile elongation, and particularly has good impact resistance.

[0033]

The polypropylene resin composition of the present invention has the following effects. (1) Excellent impact resistance. (2) Excellent elongation. (3) High rigidity. From these effects, the polypropylene resin composition of the present invention is particularly suitable as a material for home electric appliances and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Beppu 3-2, Chidori-cho, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Showa Denko K.K. 2 Showa Denko KK Kawasaki Plastics Research Laboratory (72) Inventor Kazuhiko Sakai 3-2 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Showa Denko KK Kawasaki Plastics Research Laboratory

Claims (1)

[Claims] 1. Polypropylene in an amount of 70 to 90% by weight,
5-20% by weight of a polystyrene-ethylene / propylene-polystyrene triblock copolymer having a styrene content of 15-40% by weight, and a polystyrene-ethylene / butene-polystyrene triblock copolymer having a styrene content of 15-40% by weight. It comprises 5 to 20% by weight of a polymer and 1 to 3% by weight of a polyethylene-ethylene / butene-polyethylene triblock copolymer. The polystyrene-ethylene / propylene-polystyrene triblock copolymer component and the polystyrene- A polypropylene-based resin composition, wherein the ratio of the polystyrene-ethylene / propylene-polystyrene triblock copolymer component to the total amount of the ethylene / butene-polystyrene triblock copolymer component is 20 to 80% by weight.