JP3370373B2 - Polypropylene resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition, and more particularly to a polypropylene resin composition containing a specific compound and having good physical properties.

[0002]

2. Description of the Related Art Polypropylene has various moldability, has a relatively good balance of physical properties, has excellent electrical, mechanical and chemical properties, and can be obtained at low cost. Is very well used in various fields.

Particularly, in recent years, the physical properties such as rigidity, heat distortion resistance, and surface hardness have been further improved by improving the performance of catalysts, progress of polymerization technology, and improvement of addition effect of crystallization nucleating agent. Research and improvements are being made.

Polypropylene is an inexpensive resin having excellent heat resistance and rigidity, but its crystallinity is relatively small. Therefore, if molded by an ordinary method, the balance between the rigidity and impact resistance of the molded product is the original of the resin. There is a problem that it is inferior to that of the ones, and in order to solve this problem, the molecular weight distribution is changed, the method of mixing polypropylenes having different physical properties or the addition of various nucleating agents to increase the rigidity The method of adding various rubbers to improve impact resistance is
Is generally known.

[0005]

However, although it is easy to improve either rigidity or impact resistance by the conventional methods, it is difficult to improve them in a well-balanced manner. For example, in the method of adding a nucleating agent, since the crystallinity of polypropylene only increases, the rigidity increases, but the impact resistance decreases. In addition, in the method of improving impact resistance by adding rubber, there is a problem that impact resistance can be improved because soft rubber is added, but rigidity is reduced, and the balance of physical properties is not always satisfactory. There is a desire to develop other useful compositions.

[0006]

Means for Solving the Problems The inventors of the present invention have made a diligent search for a new composition in which the balance between the rigidity and the impact resistance of polypropylene has been improved, and as a result, a composition having excellent physical properties by combining specific compounds has been obtained. The present invention has been completed by finding out that

That is, the present invention relates to crystalline polypropylene (A)
And a reactive monomer (II) different from the reactive monomer (I) capable of reacting with the grafted polypropylene (a) and the grafted polypropylene (a) in which the reactive monomer (I) is grafted to the polypropylene. A polypropylene resin composition obtained by heating and mixing a mixture (B) obtained by melt-mixing a grafted polyolefin rubber (b) grafted with rubber.

The crystalline polypropylene (A) used in the present invention is not only a propylene homopolymer but also propylene and ethylene, butene-1, as long as it is crystalline.
It may be a random copolymer or a block copolymer with other olefins such as hexene-1, and those which are commercially available or widely available in the market can be used without any trouble. The molecular weight of this crystalline polypropylene is 0.1 to 10 dl / g as the intrinsic viscosity number (hereinafter referred to as [η]) measured with a tetralin solution at 135 ° C.
The content of other olefins is 0 to 50% by weight.

In the production of these crystalline polypropylenes, the catalyst used for polymerization is, for example, a titanium trichloride catalyst or a catalyst component in which a titanium compound such as titanium trichloride or titanium tetrachloride is supported on a magnesium compound, and an alkylaluminum cocatalyst. A carrier catalyst as a component is used. Furthermore, a catalyst composed of a metal complex of a group 3 or 4 of the periodic table having a cyclopentadienyl compound represented by a combination of dicyclopentadienyl zirconium dichloride and an aluminoxane and an aluminoxane compound, or A homogeneous catalyst using a metal cation complex of Groups 3 and 4 of the Periodic Table having a cyclopentadienyl compound as a ligand can also be used.

As the polymerization method, a conventional method such as a solvent polymerization method, a bulk polymerization method in which substantially no solvent is present, or a gas phase polymerization method can be used, and the polymerization conditions are not particularly limited, and the reaction temperature is usually room temperature. ~ 200 ℃, normal pressure ~ 50kg
/ Is carried out in cm ^2.

The grafted polypropylene (a) used in the present invention is obtained by grafting a reactive monomer onto the ordinary polypropylene obtained by the above-mentioned method, and the reactive monomer (I) is Maleic anhydride, acrylic acid, methacrylic acid, glycidyl methacrylate, itaconic acid, maleic acid, fumaric acid, itaconic anhydride, N- [4- (2,3-epoxypropyl) -3,5-dimethylbenzyl] methacrylamide, Glucidyl acrylate, hydroxyl ethyl acrylate, hydroxyl ethyl methacrylate, N- [4- (2,3-epoxypropyl) -3,
5-Dimethylbenzyl] acrylamide and the like can be mentioned, which can be obtained by grafting at least one of these compounds onto polypropylene.

Further, the grafted polyolefin rubber (b) means ethylene-propylene copolymer rubber (EPR),
Ethylene-butene-1 copolymer rubber (EBR), propylene-butene-1 copolymer rubber (PBR), ethylene-propylene-diene copolymer rubber (EPDM),
Ethylene / propylene / butene terpolymer rubber (EP
BR), styrene-butadiene copolymer rubber (SB
R), hydrogenated styrene-butadiene copolymer rubber (SE
(BR) and other polyolefin-based rubbers which are grafted with a reactive monomer capable of reacting with the grafted polypropylene (a). The reactive monomers (II) include maleic anhydride, acrylic acid, methacrylic acid, Glycidyl methacrylate, itaconic acid, maleic acid, fumaric acid, itaconic anhydride, N- [4- (2,3-epoxypropyl) -3,
5-Dimethylbenzyl] methacrylamide, glycidyl acrylate, hydroxylethyl acrylate, hydroxylethyl methacrylate, N- [4- (2,3-epoxypropyl) -3,5-dimethylbenzyl] acrylamide and the like, and at least these It is obtained by grafting a kind of compound onto a polyolefin rubber.

The reactive monomer (I) used for the grafting of the polypropylene of the present invention and the reactive monomer (II) used for the grafting of the polyolefin rubber are selected from the same kind of monomers as described above. , Each of which is used as a different reactive monomer, and which can react with the grafted polypropylene (a) is a reactive monomer (I
It is essential to use as I).

As a method for synthesizing the grafted polypropylene (a) and the grafted polyolefin rubber (b), a method in which a reactive monomer is grafted to polypropylene or polyolefin rubber is usually used. For example, as a method of grafting in a solution, a polyolefin, a reactive monomer and a catalyst are dissolved in an aromatic solvent such as xylene or chlorobenzene and stirred at a temperature of 90 to 200 ° C for 0.5 to 20 hours with stirring. Perform the reaction. Further, as a method of grafting at the time of melt-kneading, after mixing the polyolefin, the reactive monomer and the catalyst, the mixture is heated at a temperature of 180 to 300 ° C. by using an extruder or a kneader to obtain 0.1 to 10 in a molten state.
It is obtained by kneading for a minute.

In any of these reactions, as a catalyst, a commonly used radical polymerization initiator can be used. Examples of the radical polymerization initiator include benzoyl peroxide, lauroyl peroxide, and peroxide. Di-t-butyl, dicumyl peroxide, cumyl butyl peroxide, peroxybenzoic acid, acetyl peroxide, t-butylperoxybenzoic acid, bis (2-ethylhexyl) peroxydicarbonate, di (n-propyl) peroxydicarbonate, etc. Can be mentioned. The amount of these catalysts used is usually 0.1 to 10 parts by weight based on 100 parts by weight of the reactive monomer.

Here, the grafting amount of the reactive monomer to the polypropylene or polyolefin rubber is 0.1 to 25% by weight of the whole, preferably 0.5 to
20% by weight.

In the present invention, the grafted polypropylene (a) and the grafted polyolefin rubber (b) are preliminarily melt-mixed with each other so that a part of each grafted portion reacts with each other to form a crosslinked structure. It is burned.
Therefore, the combination of the grafted polypropylene (a) and the grafted polyolefin rubber (b) can be arbitrarily combined, but at least the grafted reactive monomers undergo a chemical reaction to form a bond. It is necessary.

In the melt mixing of these, if necessary, as a reaction aid, for example, p-toluenesulfonic acid,
Acid catalyst such as methanesulfonic acid, sodium methoxide,
A base catalyst such as triethylamine or a Lewis acid catalyst such as tetrabutoxytitanium or dibutyltin dilaurate may be used. When using a catalyst, the addition amount is about 0.01 to 5% by weight with respect to the above mixture.

The mixing ratio of the grafted polypropylene (a) and the grafted polyolefin rubber (b) varies depending on the ratio of the respective reactive monomers grafted, but is usually 100 parts by weight of the grafted polypropylene (a). The appropriate amount of the grafted polyolefin rubber (b) is 10 to 1000 parts by weight, and the melt mixture (B) is heated and mixed at a ratio of 0.1 to 20 parts by weight with respect to 100 parts by weight of the crystalline polypropylene (A). To be done. If the use ratio exceeds the above range, the moldability is remarkably lowered and the appearance of the molded product is deteriorated, and the effect is not particularly enhanced. On the other hand, if the amount is less than that, there is no effect of improving physical properties.

To the composition of the present invention, various additives which are usually added to polypropylene, such as stabilizers, ultraviolet absorbers, lubricants, surfactants and fillers, can be added.

In the present invention, the method for mixing the above components is not particularly limited, and the components are simply mixed in advance with a tumbler, a Henschel mixer or the like, and then polypropylene is prepared by using a melt-kneading device such as an extruder or a Banbury mixer. The melting and kneading may be carried out at a temperature not lower than the melting point, generally not lower than the melting point and not higher than 280 ° C.

[0022]

The present invention will be further described with reference to the following examples.

Examples 1 to 3 Polypropylene grafted with 1.1% by weight of maleic anhydride and 1.0% by weight of N- [4- (2,3-epoxypropyl) -3,5-dimethylbenzyl] methacrylamide were grafted. Ethylene / propylene rubber was added at the ratio shown in (Table 1) and melt-mixed at 230 ° C. Further, this mixture was mixed with a polypropylene block copolymer (manufactured by Mitsui Toatsu Chemicals, Inc.,
(BJ4H) to 100 parts by weight shown in (Table 1), 0.1 part by weight of antioxidant and 0.1 part by weight of calcium stearate were added and mixed in a Henschel mixer, and then mixed by heating at 230 ° C. in an extruder. Pellets were obtained.

[Examples 1 to 3] Polypropylene grafted with 1.1% by weight of maleic anhydride (as polypropylene, manufactured by Mitsui Toatsu Chemicals, Inc.
Well Noblen ^TM (using grade JHH) and N- [4- (2,
3-epoxypropyl) -3,5-dimethylbenzyl] methacrylamide 1.0% by weight grafted ethylene / propylene rubber (as ethylene / propylene rubber Mitsui Sekiyu KK
Toughmer ^TM (Grade P-0480, manufactured by Gaku Kogyo Co., Ltd.
Using a ethylene content of 73.6% by weight, [η] = 1.94)
Added use) (in the proportions shown in Table 1) were melt-mixed at 230 ° C.. Further, this mixture was added at a ratio shown in (Table 1) to 100 parts by weight of polypropylene block copolymer (BJ4H manufactured by Mitsui Toatsu Chemicals, Inc.), and 0.1 part by weight of antioxidant and 0.1 part of calcium stearate were further added. After adding parts by weight and mixing with a Henschel mixer, 230 with an extruder
The mixture was heated and mixed at ℃ to obtain pellets.

Comparative Example 1 A polypropylene block copolymer (BJ4H, manufactured by Mitsui Toatsu Chemicals, Inc.) was used without mixing the melted mixture of grafted polypropylene and grafted ethylene / propylene rubber.
The same procedure as in Example 1 was carried out except that only the above was used. The results are shown in (Table 1).

Examples 4 to 6 Example 1 except that tetrabutoxytitanium was added as a catalyst in the proportion shown in Table 1 during the melt mixing of the grafted polypropylene and the grafted ethylene / propylene rubber.
I went the same way. The results are shown in (Table 1).

Examples 7-9 N- [4- (2,3-epoxypropyl) -3,5-dimethylbenzyl]
Example 1 was repeated except that 1.0% by weight of methacrylamide grafted polypropylene and 1.1% by weight of maleic anhydride ethylene / propylene rubber were used in the proportions shown in Table 1. The results are shown in (Table 1).

[0028]

[Table 1]

[0029]

EFFECTS OF THE INVENTION The composition of the present invention has an excellent balance of rigidity and impact resistance as compared with hitherto known compositions, and it is possible to reduce the thickness of molded products, which is extremely industrially valuable.

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Claims (3)

(57) [Claims] 1. A crystalline polypropylene (A), a grafted polypropylene (a) obtained by grafting a reactive monomer (I) onto polypropylene, and a grafted polypropylene.
a mixture (B) obtained by melt-mixing a grafted polyolefin rubber (b) in which a reactive monomer (II) different from the reactive monomer (I) capable of reacting with (a) is grafted onto a polyolefin rubber; A polypropylene resin composition obtained by heating and mixing. 2. The polypropylene resin composition according to claim 1, wherein the crystalline polypropylene (A) is 100 parts by weight and the mixture (B) is 0.1 to 20 parts by weight. 3. The polypropylene resin composition according to claim 1, wherein the melt mixing is carried out in the presence of a catalyst comprising a reaction aid.