JPH08291237A - Polypropylene-based resin composition - Google Patents

Abstract

PURPOSE: To obtain a polypropylene-based resin composition having high heat resistance and rigidity and excellent impact resistance at a low temperature and excellent in physical characteristics balance. CONSTITUTION: This resin composition comprises (A) 50-90wt.% polypropylene, (B) 1-35wt.% styrene-based saturated triblock copolymer consisting of polystyrene at the both ends and an ethylene-d-olefin copolymer in the central part, (C) 1-35wt.% styrene-based unsaturated triblock copolymer consisting of polystyrene at the both ends and a polymer containing carbon-carbon double bonds in the central part, (D) 1-30wt.% polyorganosiloxane having silicon atoms bound with hydrogen atoms and silicon atoms bound with groups having carbon- carbondouble.

Description

Detailed Description of the Invention

[0001]

This invention relates to a polypropylene resin composition having excellent low temperature impact resistance and rigidity as well as high heat resistance, which can be widely used as a material for various industrial members, foods, medical fields and the like. Regarding things.

[0002]

2. Description of the Related Art Polypropylene has excellent mechanical strength, moldability, chemical resistance, etc., and is used for industrial equipment such as office equipment, audio equipment, household appliances and various equipment such as housings and exterior materials. Widely used as a member. Furthermore, since it is excellent in hygiene, it is also used in applications such as food containers and medical instruments. As polypropylene used in these fields, a blend of polypropylene and ethylene-propylene rubber (Japanese Patent Publication No. 60-
3420), a blend polymer of polypropylene, ethylene-propylene rubber, and ethylene-butene rubber (JP-A-4-372637).

[0003]

However, in a material composed of a blend polymer of polypropylene and ethylene-propylene rubber, impact resistance is sufficient but rigidity and heat resistance are not sufficient, while polypropylene and ethylene-propylene rubber are not sufficient. A material composed of a blend polymer of rubber and ethylene-butene rubber has improved rigidity but has a drawback of low impact resistance at low temperature.

In order to solve these problems, it is an object of the present invention to provide a polypropylene resin composition having a high rigidity and an excellent low temperature impact resistance and an excellent balance of physical properties.

[0005]

[Means for Solving the Problems] The above-mentioned problems are (A) polypropylene (hereinafter referred to as (A) component) 50 to 90% by weight,
(B) Styrene-based saturated triblock copolymer (hereinafter, referred to as component (B)) 1 in which both ends of the molecule are polystyrene and the central portion is a copolymer of ethylene and α-olefin
35% by weight, both ends of the (C) molecule are polystyrene,
1 to 35% by weight of a styrene unsaturated triblock copolymer (hereinafter, referred to as component (C)) which is a polymer having a carbon-carbon double bond in the central portion, (D) a silicon atom bonded to a hydrogen atom And a polypropylene resin composition comprising 1 to 30% by weight of a polyorganosiloxane having a silicon atom bonded to a group having a carbon-carbon double bond (hereinafter referred to as component (D)). . 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, a block copolymer and a random copolymer, or a combination of two or more thereof can be used. As the comonomers of the block copolymer and the random copolymer, ethylene, butene-
Although α-olefins other than propylene such as 1, pentene-1, and hexene-1 are used, 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 100 g / 10 minutes, as measured by IS K6758 and hereinafter sometimes referred to as MFR). M
When FR is less than 5 g / 10 minutes, the fluidity of the obtained resin composition is poor and the moldability is deteriorated. MFR is 100g / 1
If it exceeds 0 minutes, the impact resistance of the resin composition is poor. These polypropylenes may be those having a low MFR within the above range by kneading and bisbreaking with an organic peroxide.

(B) Styrene-based saturated triblock copolymer The styrene-based saturated triblock copolymer used in the present invention (hereinafter sometimes referred to as the saturated triblock copolymer) has ethylene in the central part of the molecule. Is a polymer alone or a mixture thereof in which random or alternating copolymer blocks of α-olefin and α-olefin (hereinafter sometimes referred to as ethylene / α-olefin block) are located, and polystyrene blocks are located on both sides thereof. The α-olefin referred to here is propylene, butene-1, pentene-
1, hexene-1, octene-1, 4-methyl-pentene-1 and the like. Generally, a styrene-butadiene-styrene polymer or styrene-isoprene-
It can be produced by hydrogenating a styrene polymer or the like.
In this saturated triblock copolymer molecule, polystyrene blocks located at both ends and ethylene / α-in the center
In the bonding portion with the olefin block, each component may not be clearly separated, and styrene and ethylene / α
-The components of the olefin may be mixed with each other, and the concentration of each component gradually changes from the component of one block to the component of the other block, which is a so-called tapered type. May be. The polystyrene block content of this saturated triblock copolymer is preferably 10 to 70% by weight. When the content of the polystyrene block is less than 10% by weight, impact resistance and rigidity of the obtained polypropylene resin composition are reduced, and when it exceeds 70% by weight, impact resistance and fluidity of the polypropylene resin composition are reduced. To do.

The MFR of the saturated triblock copolymer is
0.5 to 100 g / 10 minutes is preferable, 5 to 50 g / 1
0 minutes is more preferred. If the MFR is less than 0.5 g / 10 minutes, the fluidity of the resulting resin composition will be poor and the moldability will be poor, and if it exceeds 100 g / 10 minutes, the impact resistance of the resin composition will be poor.

The content of α-olefin in the random or alternating copolymer block of ethylene and α-olefin located in the central portion of the saturated triblock copolymer is
5-60 mol% is preferable. If the content of butene and propylene is outside this range, the compatibility of the (B) saturated triblock copolymer and (A) polypropylene deteriorates and the impact resistance of the resulting polypropylene resin composition decreases. Further, when it exceeds 60 mol%, the heat resistance of the polypropylene resin composition is lowered.

(C) Styrene-based unsaturated triblock copolymer The styrene-based unsaturated triblock copolymer (hereinafter sometimes referred to as unsaturated triblock copolymer) used in the present invention has a molecular center. A polymer block containing a carbon-carbon double bond is located in a part, and polystyrene blocks are located on both sides of the polymer block. A homopolymer or a copolymer of a conjugated double bond compound such as butadiene, isoprene, and 1,3-pentadiene can be used in the central portion here. In the bonding portion of the polystyrene block located at both ends and the polymer block located in the center located in the unsaturated triblock copolymer molecule, the respective components are not clearly separated. Alternatively, styrene and each component of the polymer containing a carbon-carbon double bond may have a mixed portion, and the concentration of each component gradually increases from the component of one block to the component of the other block. It may be a so-called tapered type that changes into components. The content of polystyrene block in this unsaturated triblock copolymer is 5-80.
% By weight. When the content of polystyrene block is less than 5% by weight, (C) an unsaturated triblock copolymer and (B)
When the compatibility with the saturated triblock copolymer deteriorates, the impact resistance of the polypropylene resin composition obtained decreases,
If it exceeds 0% by weight, low-temperature impact resistance and fluidity of the polypropylene resin composition are deteriorated.

Further, the polymer block containing a carbon-carbon double bond located in the central portion of the unsaturated triblock copolymer may be partially hydrogenated.

The MFR of the unsaturated triblock copolymer is
0.5 to 100 g / 10 minutes is preferable, 1 to 50 g / 1
0 minutes is more preferred. If the MFR is less than 0.5 g / 10 minutes, the fluidity of the obtained resin composition will be poor and the moldability will be poor, and if the MFR is more than 100 g / 10 minutes, the impact resistance of the resin composition will be poor.

(D) Polyorganosiloxane The polyorganosiloxane used in the present invention has a silicon atom bonded to a hydrogen atom and a silicon atom bonded to a group having a carbon-carbon double bond. The number of repeating units (degree of polymerization) is in the range of 10 to 50,000. Specifically, a polyorganosiloxane having at least one silicon atom bonded to a hydrogen atom and at least one silicon atom bonded to a group having a carbon-carbon double bond in one molecule. (Hereinafter, also referred to as polysiloxane A), or having a polyorganosiloxane having two or more silicon atoms bonded to hydrogen atoms and a carbon-carbon double bond in one molecule. It may be a mixture of polyorganosiloxanes having two or more silicon atoms bonded to a group (hereinafter also referred to as polysiloxane B) or a mixture of polysiloxane A and polysiloxane B.

The ratio of the silicon atom bonded to the group having a carbon-carbon double bond to the silicon atom bonded to the hydrogen atom in the polyorganosiloxane is preferably 0.1 to 1.3. If this ratio is larger than 1.3, the heat resistance of the polypropylene-based resin composition obtained from the remaining groups having a carbon-carbon double bond decreases, and if it is smaller than 0.1, the production of the polypropylene-based resin composition. It is easy to foam inside or during molding of the obtained resin composition.

The polyorganosiloxane may be linear or branched, and may be used as a mixture thereof. Examples of the group having a carbon-carbon double bond in this case include a vinyl group, an allyl group, 1-
Although a butenyl group and the like can be mentioned, a vinyl group is most preferable in terms of easiness of synthesis. The organic group bonded to a silicon atom excluding a group having a hydrogen atom bonded to the silicon atom and a carbon-carbon double bond in the molecule of the polyorganosiloxane, for example, a methyl group,
Alkyl groups such as ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, aryl groups such as phenyl group, β-phenylethyl group, β-
An unsubstituted hydrocarbon group such as an aralkyl group such as a phenylpropyl group, and a chloromethyl group, a cyanoethyl group,
Substituted hydrocarbon groups such as 3,3,3-trifluoropropyl group and the like can be mentioned. Of these, a methyl group is preferable from the viewpoint of ease of synthesis and good physical properties of the resulting polypropylene resin composition, and in order to improve low temperature impact resistance, 10 mol of these organic groups are preferable. %
It is more preferable that the following are phenyl groups.

The polyorganosiloxane has a viscosity at 25 ° C. of preferably 1 to 1000 P, more preferably 3 to 50 P. If the viscosity is too high, it will be difficult to mix it uniformly in the composition, and if it is too low, the impact resistance of the resulting polypropylene resin composition will be reduced.

Further, the polyorganosiloxane used in the present invention includes (D) a group having a hydrogen atom bonded to a silicon atom in the polyorganosiloxane and a carbon-carbon double bond bonded to the silicon atom, and (C) an unsaturated group. A catalyst for addition reaction used for promoting the reaction with the carbon-carbon double bond in the triblock copolymer may be added. For example, chloroplatinic acid, an alcohol-modified solution of chloroplatinic acid, platinum-based compounds such as coordination compounds of chloroplatinic acid and olefins or vinyl siloxane, tetrakis (triphenylphosphine) palladium, chlorotris (triphenylphosphine) rhodium, etc. And a platinum-based compound is preferable.

In addition to the above addition reaction catalyst, conventionally known reaction inhibitors such as polymethylvinylsiloxane cyclic compounds, acetylene compounds, organic phosphorus compounds, so-called silicone rubber curing accelerators, silicone rubber curing inhibitors, etc. It can be added to control the reaction between the component (D) and the component (C).

Examples of such polyorganosiloxanes include those generally called modified silicone oils, addition reaction type silicone adhesives, addition reaction type silicone gels, addition reaction type silicone RTV rubbers, and the like.

(Composition ratio) The ratio of the component (A) in the polypropylene resin composition of the present invention is 50 to 90% by weight.
Is. If the proportion of the component (A) is less than 50% by weight, the heat resistance will decrease, and if it exceeds 90% by weight, the impact resistance will decrease. On the other hand, it occupies in the polypropylene resin composition of the present invention
The proportion of the component (B) is 1 to 35% by weight, preferably 2 to 15% by weight. If the composition ratio of the component (B) in the resin composition is less than 1% by weight, the impact resistance of the obtained polypropylene resin composition is lowered, and if it exceeds 35% by weight, heat resistance and rigidity (flexural modulus) Becomes worse. Similarly, the proportion of the component (C) in the polypropylene resin composition of the present invention is 1 to 35% by weight, preferably 2 to 15% by weight. The composition ratio of the component (C) in the resin composition is 1
If it is less than 35% by weight, the impact resistance of the resulting polypropylene resin composition is lowered, and if it exceeds 35% by weight, heat resistance and rigidity (flexural modulus) are deteriorated.

Further, the proportion of the component (D) in the polypropylene resin composition of the present invention is 1 to 30% by weight, preferably 2 to 15% by weight. When the composition ratio of the component (D) in the resin composition is less than 1% by weight, the low temperature impact resistance of the obtained polypropylene resin composition decreases, and when it exceeds 30% by weight, heat resistance and rigidity (flexural modulus) )
Not only deteriorates, but also the impact resistance decreases.

The content of the addition reaction catalyst in the present invention is 0.
It is preferably 1 to 10000 ppm by weight, and 3 to
More preferably 100 ppm by weight. 10,000 weight p
If it exceeds pm, discoloration due to heat deterioration or the like may occur, and 0.
If it is less than 1 ppm by weight, the effect as a catalyst is not obtained and the impact resistance is lowered.

Further, the rubber component in the component (A) and the component (B),
The total amount of the component (C) and the component (D) (hereinafter sometimes referred to as the total rubber component) is preferably 5 to 50% by weight based on the entire polypropylene resin composition. If the content of all rubber components in the total polypropylene-based resin composition is less than 5% by weight, impact resistance of the obtained polypropylene-based resin composition decreases, and if it exceeds 50% by weight, heat resistance decreases.

(Method for Producing Polypropylene Resin Composition) In producing the polypropylene resin composition of the present invention, a stabilizer against heat, oxygen and light and a flame retardant widely used in the field of synthetic resins and synthetic rubbers. , Additives such as fillers, colorants, lubricants, plasticizers and antistatic agents, polyethylene-based polymers, poly-4-
The characteristics of the polypropylene resin composition of the present invention are essentially obtained by using a polymer such as methyl-1-pentene polymer, polystyrene, polybutadiene or styrene graft polymer of polyisoprene, polyester, polyamide, polycarbonate, etc. according to the purpose of use. You may add it in the range which does not impair.

Further, in the polypropylene resin composition of the present invention, the addition reaction catalyst, the reaction inhibitor, the silicone rubber curing accelerator, the silicone rubber curing inhibitor and the like are added separately from the (D) polyorganosiloxane, (D) component and (C)
It is also possible to control the reaction with the components.

The polypropylene resin composition of the present invention achieves the object by uniformly blending the above-mentioned respective components (A), (B), (C) and (D), an addition reaction catalyst and an additive. You can The compounding method (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 or a ribbon mixer, and a melting method such as an open roll, an extrusion mixer, a kneader or a Banbury while melting. There is a method of mixing. Among these methods, in order to obtain a more uniform resin composition, it is advisable to use two or more of these mixing methods in combination (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, whether it is melt-mixed or molded by the molding method described later. However, since the resin is thermally decomposed and deteriorated when it is carried out at a high temperature, it is generally carried out at 150 to 350 ° C (preferably 170 to 250 ° 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 and a hollow molding method which are 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.

[0030]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. In the following examples and comparative examples, each physical property was measured by the following methods. Izod impact strength (IZOD) is -30 according to ASTM D265
It was measured with a notch at a temperature of ° C. Heat distortion temperature (HDT) was measured according to ASTM D648 under a load of 66 psi. The flexural modulus was measured according to ASTM D790 at a temperature of 23 ° C.

The types and physical properties of the components (A), (B), (C) and (D) used in the examples and comparative examples are as follows.

(A) Polypropylene (PP) As polypropylene, MFR3 manufactured by Showa Denko KK
Homotype polypropylene MA810 for 0 g / 10 min
B (PP-1), MFR 40g / 10 minutes, rubber content 18
Weight% block type polypropylene MK712H
(PP-2) was used.

(B) Saturated triblock copolymer and (C)
Unsaturated triblock copolymer Saturated triblock copolymer and unsaturated triblock copolymer (hereinafter abbreviated as TBC1 and TBC2) are shown in Table 1.
I used the one.

[0034]

[Table 1]

(D) Polyorganosiloxane As the polyorganosiloxane, a group having a carbon-carbon double bond bonded to a silicon atom and a hydrogen atom bonded to the silicon atom react with each other by heating to crosslink / gelate,
KE1055 manufactured by Shin-Etsu Chemical Co., Ltd., which has an unreacted state and a viscosity of 7 P at 25 ° C.
The viscosity at 25 ° C. in the unreacted state with (POS-1) is 3
5P addition reaction type silicone adhesive KE1842 (POS-2) manufactured by Shin-Etsu Chemical Co., Ltd. was used.

For comparison, instead of the components (B), (C) and (D), ethylene / propylene rubber (intrinsic viscosity [η]
= 2.5 dl / g, propylene content 25% by weight, hereinafter E
PR), ethylene / butene rubber (intrinsic viscosity [η]
= 3.5 dl / g, butene content 15% by weight, below, EB
R) was used.

These components were blended in the proportions shown in Table 2 and dry blended for 5 minutes with a Henschel mixer. The obtained mixture was kneaded using a twin-screw extruder of the same direction (diameter 30 mm) set at 200 ° C. to produce pellets. The pellets were injection molded using an injection molding machine set at 230 ° C. to prepare test pieces for measurement. Table 2 shows the results of Izod impact test, flexural modulus, and tensile elongation of each test piece.

[0038]

[Table 2]

(Example 1) In Example 1 of Table 2, the homotype polypropylene MA810B (PP) was used as the component (A).
-1) and (B) component TBC1-1 which is ethylene / butene random copolymer in the central part, (C) component TBC2-1 whose central part is polybutadiene, and (D) addition reaction type silicone gel Is a polypropylene-based resin composition of the present invention obtained by blending POS-1 of 80% by weight, 8% by weight, 6% by weight, and 6% by weight, respectively. Example 1 was excellent in low-temperature impact resistance, rigidity and heat resistance, and particularly good in impact resistance.

(Comparative Examples 1 and 2) Comparative Examples 1 and 2 in contrast to Example 1 are combinations of polypropylene and ethylene-propylene rubber, which are known as prior art, and polypropylene and ethylene-butene rubber. The polypropylene-based resin composition obtained in the same manner as in Example 1 with the total amount of rubber components had a poor balance of low temperature impact resistance, rigidity and heat resistance, and particularly poor low temperature impact resistance.

(Examples 2 to 6) Polypropylene in which the composition ratios and types of the components (A), (B), (C) and (D) were changed from those of Example 1 as shown in Table 2. The resin composition was also excellent in low temperature impact resistance, rigidity and heat resistance, and particularly good in impact resistance.

(Comparative Examples 3 and 4) In the case of Comparative Examples 3 and 4 in which the composition ratio, structure and kind of the polypropylene resin composition were out of the scope of the present invention, the physical properties of the resin compositions obtained were poor.

[0043]

The polypropylene resin composition of the present invention exhibits the following effects. (1) Excellent low temperature impact resistance. (2) It has excellent heat resistance. (3) High rigidity. Since the polypropylene resin composition of the present invention exhibits the above effects, it is suitable as a material from various industrial members to foods, medical fields and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Maeda Inventor Hiroyuki Maeda 3-2 Chidori-cho, Kawasaki-ku, Kanagawa Prefecture Showa Electric Works Ltd. Kawasaki Plastic Research Laboratory (72) Yoshimi Shimizu Chidori-cho, Kawasaki-ku, Kanagawa Prefecture No. 3 No. 2 Showa Electric Co., Ltd. Kawasaki Plastics Research Laboratory (72) Inventor Yoshihiro Mogi 3-2 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Showa Electric Co., Ltd. Kawasaki Plastics Research Laboratory

Claims (2)

[Claims] 1. (A) 50 to 90% by weight of polypropylene (hereinafter referred to as "component (A)"), (B) both ends of the molecule are polystyrene, and the central part is a copolymer of ethylene and α-olefin. Styrene-based saturated triblock copolymer (hereinafter, referred to as (B) component) 1 to 35% by weight, (C) molecule has polystyrene at both ends, and a central portion is a polymer containing a carbon-carbon double bond A certain styrene unsaturated triblock copolymer (hereinafter referred to as (C) component) 1 to 35% by weight,
(D) a polyorganosiloxane having a silicon atom bonded to a hydrogen atom and a silicon atom bonded to a group having a carbon-carbon double bond (hereinafter referred to as (D) component) 1 to
A polypropylene resin composition comprising 30% by weight. 2. A rubber component, a component (B) and a component (C) in the component (A).
The total amount of the component and the component (D) is 5 to 50% by weight in the composition.
The polypropylene-based resin composition according to claim 1, wherein