JPH05339433A - Polyolefinic resin composition - Google Patents

Abstract

PURPOSE:To provide the subject composition high in viscosity and melt-tension, excellent in processability, impact resistance and rigidity and useful for molding, etc., which comprises a polyolefin and a specific core-shell graft copolymer in a specified ratio. CONSTITUTION:The objective composition comprises (A) 100 pts.wt. of a polyolefin such as a polymer obtained by polymerizing monomers containing >=50wt.% of propylene and (B) 0.1-100 pts.wt. of a core-shell graft copolymer obtained by graft-copolymerizing (i) 40-95 pts. of a rubbery polymer such as polybutadiene and (ii) 60-5 pts. of a monomer component comprising a vinylic compound such as styrene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin composition which is obtained by mixing a polyolefin and a core-shell graft copolymer and is excellent in processability, impact resistance, rigidity and the like.

[0002]

2. Description of the Related Art Polyolefin is widely used because it is inexpensive and has excellent physical properties. However, polypropylene, for example, has the following drawbacks. That is, 1) the viscosity and tension at the time of melting are low, and therefore the vacuum formability (hereinafter referred to as thermoformability) of the sheet, the calender moldability, the blow moldability, the foam moldability, etc. are low. It is lower than that of polyvinyl chloride, ABS resin, etc., and 3) it has low impact resistance at low temperature.

In order to improve the processability of the polypropylene, it is widely and generally practiced to mechanically mix polyethylene and the like, but the effect of improving the processability is still insufficient, and therefore many polyethylene components are added. Required, which leads to a decrease in rigidity.

Further, the viscosity and the tension at the time of melting have been improved by increasing the molecular weight of polyolefin, but polyolefin having a large molecular weight makes it difficult to perform extrusion molding, injection molding and the like, which are important processing methods. It is not preferable because

Conventionally, a core-shell type modifier which has been widely used as an impact resistance improver in a polyvinyl chloride resin or the like can efficiently disperse a rubber component (core portion) having a preset particle diameter. It is an excellent method of suppressing the decrease in rigidity and improving the impact resistance. However, in non-polar polyolefins,
It is considered that the core-shell type modifier has low compatibility and cannot be used. Therefore, no attempt has been made to improve the processability by mixing the core-shell type modifier alone with the polyolefin.

It is disclosed in Japanese Patent Application Laid-open No. HEI 3-103 that a core-shell type modifier is added to a polyolefin in the presence of a specific compatibilizer.
Although known from 185037, U.S. Pat.No. 4,997,884, etc., there is a problem that the synthesis of the compatibilizing agent is complicated and the cost of using the compatibilizing agent and the system are complicated. Not preferable.

As described above, the fact is that a polyolefin resin having excellent workability, impact resistance, rigidity and the like has not yet been obtained.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a polyolefin resin composition having excellent processability, impact resistance and rigidity by mixing a core-shell graft copolymer with polyolefin. .

[0009]

Means for Solving the Problems As a result of intensive studies, the inventors have found that mixing a core-shell graft copolymer with a polyolefin increases the tension at the time of melting, improves the workability, and improves the impact resistance, The present invention has been completed by finding that a polyolefin resin composition having excellent rigidity can be obtained.

That is, the present invention relates to A) polyolefin 10
A core obtained by graft-copolymerizing 0 parts (parts by weight, the same applies hereinafter) and 40 to 95 parts of B) a rubber-like polymer (a) with 60 to 5 parts of a monomer component (b) consisting of a vinyl compound. The present invention relates to a polyolefin-based resin composition comprising 0.1 to 100 parts of shell graft copolymer.

[0011]

In the present invention, by controlling the viscosity and / or tension at the time of melting, the drawdown of the sheet and the parison, the continuous foaming of the foam cells, etc. are improved, and the thermoformability, calender moldability, Provided is a polyolefin resin composition having excellent blow moldability and foam moldability. The impact resistance is improved in all processing methods related to polyolefin such as injection molding, extrusion molding, thermoforming, calender molding, blow molding and foam molding.

The polyolefin used in the present invention includes:
For example, polypropylene, high density, low density, and linear low density polyethylene, poly-1-butene, polyisobutylene, copolymers of ethylene and propylene in all ratios, diene components of 10 in all ratios of ethylene and propylene. % (% By weight, the same shall apply hereinafter) or less ethylene-propylene-diene terpolymer, polymethylpentene, ethylene or propylene and 50% or less vinyl acetate, methacrylic acid alkyl ester, acrylic acid alkyl ester, aromatic vinyl Random, block, and graft copolymers with vinyl compounds and the like. As a polyolefin, propylene is 50
% Of propylene-based polyolefin obtained by polymerizing monomers containing 50% or more of propylene, and polyethylene 0-10.
It is preferable that 0 part of the mixture has a melt flow index at 230 ° C. of 4 or less so that the kneading and dispersibility of the graft copolymer are good and the effect of the present invention is exhibited.

The graft copolymer used for improving the impact resistance and processability of the polyolefin in the present invention is a core-shell type graft having a rubber polymer as a core and a vinyl hard polymer as a shell. It is a copolymer. The core-shell graft copolymer referred to in the present invention is a concept including a graft copolymer of a hard shell component in the presence of a rubber-like polymer forming a core.

Conventionally, the core-shell type graft copolymer has been widely used as an impact resistance improving agent such as polyvinyl chloride, but the non-polar polyolefin and the core-shell graft copolymer are compatible with each other. Is completely unimaginable from the conventional knowledge, and no attempt has been made to use this as a polyolefin processability improving agent or impact resistance agent without the presence of a compatibilizing agent.

In the present invention, by mixing the core-shell graft copolymer with the polyolefin, the tension at the time of melting is increased, the processability is improved, and a polyolefin resin composition excellent in impact resistance and rigidity is obtained. available.

The core-shell graft copolymer used in the present invention can be obtained by graft-copolymerizing a rubber-like polymer (a) with a monomer component (b) composed of a vinyl compound.

The rubbery polymer (a) is a polymer having a glass transition temperature of 25 ° C. or lower, such as polybutadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, and diene acrylate-n-butyl-butadiene rubber. Acrylic rubbers such as rubbers, n-butyl polyacrylate, and 2-ethylhexyl polyacrylate,
Representative examples are ethylene-propylene-diene rubber, olefin rubber such as butyl rubber, and silicone rubber such as polydimethylsiloxane. These may be used alone or in combination of two or more. In particular, those obtained by polymerizing a monomer having a butadiene content of 50% or more are preferable in terms of compatibility with polyolefin.

Examples of the vinyl compound as the monomer component (b) include aromatic vinyl compounds such as styrene and α-methylstyrene, alkyl methacrylates such as methyl methacrylate, ethyl methacrylate and -n-butyl methacrylate, Acrylic alkyl esters such as ethyl acrylate, -n-butyl acrylate, acrylonitrile,
Representative examples include unsaturated nitrile compounds such as methacrylonitrile. Further, acid anhydride groups, carboxylic acid groups, amino groups, vinyl compounds having a reactive functional group such as a hydroxy group, for example, maleic anhydride, methacrylic acid, acrylic acid, methacrylamide, acrylamide, dimethylaminoethyl methacrylate, etc., It is also possible to use hydroxyethyl methacrylate, hydroxyethyl acrylate or the like.

These vinyl compounds may be used as a mixture of two or more, if necessary.

As the monomer component (b), at least one kind of the aromatic vinyl compound and / or the methacrylic acid alkyl ester is used in an amount of 100 to 50%, and 0 to 50% of other vinyl compounds copolymerizable therewith. % Is preferable. If the content of the components other than the aromatic vinyl compound and the methacrylic acid alkyl ester exceeds 50%, the polymerizability is lowered and the cost is increased, which is not preferable.

Among the above-mentioned monomer components, styrene and α-methylstyrene are used as the aromatic vinyl, and methacrylic acid alkyl ester having 1 to 4 carbon atoms is used as the methacrylic acid alkyl ester because of their high polymerizability and cost. Particularly preferred in terms of aspect.

The core-shell graft copolymer comprises 40 to 95 parts of the rubber-like polymer (a) and 60 to 5 parts of the monomer component (b) consisting of a vinyl compound, preferably the rubber-like polymer (a). Graft copolymerization of 40 to 95 parts with a monomer component (b) consisting of 100 to 50% of at least one of aromatic vinyl and alkyl methacrylate, and 0 to 50% of other copolymerizable vinyl compounds. To be When the content of the rubber-like polymer (a) is 40 parts or less, the processability and impact resistance improving effect are lowered, and when it is 95 parts or more, the graft copolymer is agglomerated, which is not preferable.

The core-shell graft copolymer can be polymerized by ordinary radical polymerization, and a polymerization method such as suspension polymerization or emulsion polymerization is used. From the viewpoint of controlling the particle system and particle structure, emulsion polymerization is preferred. Also, acid,
The particles can be enlarged by adding a salt, a coagulant or the like. The particle size is preferably 3 μm or less from the viewpoint of surface property.

The polyolefin composition having good processability, impact resistance and rigidity in the present invention can be obtained by mixing the polyolefin with the core-shell graft copolymer. The mixing ratio is preferably 0.1 to 100 parts of the core-shell graft copolymer with respect to 100 parts of the polyolefin, and particularly preferably 0.5 to 70 parts of the core-shell graft copolymer. When the content of the core-shell graft copolymer is less than 0.1 part, the effect of improving the processability and impact resistance is insufficient, and when it exceeds 100 parts, the original properties of the polyolefin are lost, which is not preferable.

If necessary, an inorganic filler such as calcium carbonate or talc, a stabilizer, a lubricant or the like may be added to the polyolefin resin compound of the present invention.
If necessary, a core-shell type processability improver used in conventional polyvinyl chloride resins can be added.

As a method for mixing the graft copolymer and the polyolefin, conventionally well-known methods such as extrusion kneading method and roll kneading method can be used. Also, a graft copolymer,
It is also possible to carry out multi-stage mixing such as mixing the inorganic filler and a part of the polyolefin and then adding and mixing the rest of the polyolefin.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Graft copolymerization of 30 parts of a monomer component consisting of 15 parts of methyl methacrylate and 15 parts of styrene by ordinary emulsion polymerization in the presence of 70 parts (solid content) of polybutadiene rubber latex having a particle size of 0.25 μm. did. Final conversion is 98%, particle size is 0.26
was μm.

The obtained polymer latex was salted out by a usual method, dehydrated and dried. 20 parts of the obtained graft copolymer powder was mixed with 100 parts of polypropylene (Highball-B-200) manufactured by Mitsui Petrochemical Co., Ltd., and various test pieces were obtained by roll kneading at 200 ° C. and press molding. The composition is shown in Table 1.

Using the above test piece, ASTM-D 256, A
According to STM-D790, Izod impact resistance test and bending elasticity test were performed.

Similarly, a 100 mm square and a thickness of 1.5 mm
Sheet, and fix it with a clamp with a 76 mm square opening,
Sheet drawdown was measured for 30 minutes during the 190 ° C open.

Further, 20 parts of the obtained graft copolymer powder was blended and mixed in the same manner as above, and the mixture was mixed with an extruder of Brabender Plasticorder made by Brabender Co., Ltd.
It was extruded at 40 ° C. and pelletized at 40 rpm. The obtained pellets are manufactured by Toyo Seiki Co., Ltd. using a Capillograph at 200 ° C and a die 2
mm × 10mm, extrusion speed 20mm / min, take-up speed 1
Melt tension in m / min was measured.

In addition, ASTM-
According to D1238, the melt flow index at 230 ° C. was measured.

The obtained results are shown in Table 2.

Example 2 Various test pieces were obtained in the same manner as in Example 1 except that the amount of the graft copolymer was changed as shown in Table 1, and various tests were conducted in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 1 Polypropylene manufactured by Mitsui Petrochemical (Hypol-B-200
) Alone, various tests were conducted in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 2 Mitsui Petrochemical Polypropylene (Hipol-B-200
) 20 parts of rhodenity polyethylene having a melt flow rate of 0.25 at 190 ° C. was added to 100 parts of each kind of test piece in the same manner as in Example 1, and the same test as in Example 1 was carried out. The results are shown in Table 2.

Comparative Example 3 Various test pieces were prepared in the same manner as in Example 1 except that the amount of rhodity polyethylene was changed as shown in Table 1, and the test was conducted in the same manner as in Example 1. The results are shown in Table 2.
Shown in.

[0039]

[Table 1]

[0040]

[Table 2]

From Tables 1 and 2, the polyolefin resin compositions of the present invention (Examples 1 and 2) in which the graft copolymer was mixed with polyolefin were polypropylene (Comparative Example 1) and conventional polyethylene mixed ( Comparative example 2,
Compared to 3), the viscosity due to melt flow index,
It can be seen that the melt tension is increased and the workability, especially the drawdown of the sheet, is improved. It is also found that the workability, impact resistance and rigidity are well balanced.

[0042]

EFFECT OF THE INVENTION The polyolefin resin composition of the present invention has high viscosity and melt tension according to the melt flow index, improved processability, and at the same time has a small drawdown when formed into a sheet. Furthermore, its workability and impact resistance,
Excellent balance with rigidity.

Claims (9)

[Claims] 1. A graft copolymerization of A) 100 parts by weight of polyolefin, B) 40 to 95 parts by weight of a rubber-like polymer (a) and 60 to 5 parts by weight of a monomer component (b) composed of a vinyl compound. A polyolefin resin composition comprising 0.1 to 100 parts by weight of the obtained core-shell graft copolymer. 2. At least 50% by weight of polyolefin.
The polyolefin resin composition according to claim 1, which is obtained by polymerizing the propylene-containing monomer. 3. At least 50% by weight of polyolefin.
100 parts by weight of propylene-based polyolefin obtained by polymerizing the propylene-containing monomer of
A mixture of 0 parts by weight and 0 parts by weight.
Alternatively, the polyolefin-based resin composition according to item 2. 4. The polyolefin resin composition according to claim 1, 2 or 3, wherein the polyolefin has a melt flow index at 230 ° C. of 4 or less. 5. The polyolefin resin composition according to claim 1, wherein the rubber-like polymer (a) is obtained by polymerizing a monomer containing butadiene in an amount of 50% by weight or more. 6. The monomer component (b) comprises 100 to 50% by weight of at least one kind of aromatic vinyl and / or methacrylic acid alkyl ester and 0 to 50% by weight of other copolymerizable vinyl compound. The polyolefin resin composition according to claim 1, wherein 7. The aromatic vinyl is styrene and / or α-methylstyrene, and the methacrylic acid alkyl ester is a methacrylic acid alkyl ester having 1 to 4 carbon atoms in the alkyl group. Polyolefin resin composition. 8. The core-shell graft copolymer is obtained by emulsion polymerization.
The polyolefin resin composition described. 9. The polyolefin resin composition according to claim 1, wherein the core-shell graft copolymer has an average particle diameter of 3 μm or less.