JPS60212441A - Propylene polymer composition - Google Patents

Abstract

PURPOSE:A composition, obtained by adding a copolymer prepared by graft modifying an unsaturated carboxylic acid (derivative) onto a specific ethylene-alpha- olefin copolymer to a mixed system of polypropylene with an inorganic filler, and having improved impact resistance, surface hardness and rigidity. CONSTITUTION:A propylene polymer composition obtained by incorporating (A) 98-49wt% propylene polymer, preferably homopolymer or a copolymer thereof with ethylene having preferably 0.89-0.93g/cm<3> density and 0.01-50g/10min melt flow rate with (B) 1-50wt% powdery inorganic filler, preferably talc having 1- 20mu average particle diameter and (C) 1-50wt% ethylene-alpha-olefin copolymer prepared by graft modifying 0.01-5pts.wt. unsaturated carboxylic acid (derivative), preferably maleic anhydride onto 100pts.wt. ethylene-alpha-olefin copolymer having 0-50% crystallinity measured by X-ray diffractometry and 55-95mol% ethylene content, and melt kneading the resultant mixture in an extruder, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polypropylene composition having excellent impact resistance, surface hardness and rigidity.

Crystalline polypropylene (hereinafter sometimes referred to as PP) has excellent rigidity, surface hardness, heat resistance, etc., but has the drawback of poor impact resistance. As a method of improving impact resistance, it has been known and widely practiced to mix rubber-like substances such as polyisobutylene, polybutadiene, amorphous ethylene-propylene copolymer, or polyethylene with PP. . However, on the other hand, these modified materials are softer than PP and have a lower softening point, so they have the disadvantage of reducing the inherent characteristics of PP, such as rigidity, surface hardness, heat resistance, etc.

As a method to eliminate such drawbacks, a method of mixing a specific talc into a mixture of a crystalline ethylene/propylene block copolymer and an amorphous ethylene/α-olefin copolymer (Japanese Patent Application Laid-Open No. 53-64257), A method of mixing specific calcium carbonate into a mixture of propylene polymer and ethylene-propylene copolymer rubber (Japanese Patent Laid-Open No. 57-70
No. 141) Furthermore, there is a method of mixing an inorganic filler, such as a method of mixing an ethylene polymer and a specific talc etc. with a mixture of a crystalline propylene polymer and a rubbery component (Japanese Patent Application Laid-open No. 73034/1983). Proposed.

However, although these methods improve rigidity and heat resistance, they have the disadvantage of decreasing impact resistance.

On the other hand, when an inorganic filler such as calcium carbonate or talc is added to PP, a method of adding a polyolefin having a carboxylic anhydride group to increase the affinity between the PP and the inorganic filler (Japanese Unexamined Patent Publication No. 48/1989) 97947), and a method of melt-mixing an organic peroxide in addition to an unsaturated carboxylic acid-modified polyolefin resin (Japanese Patent Application Laid-Open No. 131031/1982), but these systems have poor impact resistance. Not improved.

In view of the current situation, the present inventor investigated the development of polypropylene that has a good balance between iφi impact resistance, surface hardness, and rigidity. It has been found that the object of the present invention can be achieved by adding a modified ethylene copolymer graft-modified with an unsaturated carboxylic acid or a derivative thereof to the polymer, and the present invention has been achieved.

That is, the present invention provides a propylene polymer (A > 98 to 49% by weight, powdered inorganic filler (B) 1 to 50% by weight, X-ray crystallinity O to 50%, and ethylene content 55 to 95 mol%). To 100 parts by weight of the ethylene/α-olefin copolymer (C) was added 0.0 parts of a graft monomer selected from unsaturated carboxylic acids or derivatives thereof.
01 to 5 parts by weight graft-modified modified ethylene α
-Olefin copolymer (D) A propylene polymer composition characterized by comprising 1 to 50% by weight and having excellent impact resistance, surface hardness and rigidity.

The propylene polymer (A) used in the present invention is crystalline and preferably has a density of 0.89 to 0.93.
g/cJ and melt flow rate (MFR: A
S TM 0123B, L) is 0.01 to 50g
/10m1n, and 30 mol% or less of propylene homopolymer or propylene, more preferably,
25 mol% or less of ethylene, 1-butene, 4-methyl-
It is a block or random copolymer with α-olefins such as 1-pentene, 1-hexene, and 1-octene. Among these, propylene homopolymers and block copolymers with ethylene are preferred.

The powdered inorganic filler (B) used in the present invention is an inorganic powdered filler, and specifically includes, for example, heavy calcium carbonate, precipitated calcium carbonate, hydrous basic magnesium carbonate, kaolin clay, and pyrophyllide. Examples include light, talc, sericite, calcined ray, asbestos, mica, calcium silicate, barium sulfate, calcium sulfate, silica, and the like. Among them, talc with an average particle size of 1 to 20 μm is preferred.

The modified ethylene/α-olefin copolymer [1]) used in the present invention has a crystallinity of 0 to 50% by X-rays, preferably 0 to 40%, more preferably 10 to 30% and ethylene. Ethylene/α-olefin copolymer (with a content of 55 to 95 mol%, preferably 60 to 93 mol%, more preferably 85 to 93 mol%)
C) 0.01 to 5 of a graft monomer selected from unsaturated carboxylic acids or derivatives thereof per 100 parts by weight.
Parts by weight, preferably 0.1 to 4 parts by weight, of a graft-modified copolymer.

Even if a copolymer graft-modified with an ethylene/α-olefin copolymer (C) with a crystallinity of 50% and an ethylene content of more than 95 mol% is used, the impact resistance of the propylene polymer composition remains the same. Not improved. On the other hand, even if a copolymer obtained by modifying an ethylene/α-olefin copolymer having an ethylene content of less than 55 mol % is used, the impact resistance of the propylene polymer composition is not improved, and the heat resistance etc. are also lowered. The ethylene/α-olefin copolymer (C) usually has a melt flow rate (MFR: ASTM D 1238.
L) is preferably in the range of 0.01 to 20 g/10 m1n, more preferably 0.05 to 10 g/10 m1n. When a copolymer having a VFR outside the above range is used, the difference in melt viscosity between the modified ethylene/α-olefin copolymer (D) obtained from the copolymer and the propylene polymer (A) The dispersion of each component is not necessarily sufficient, and the effect of improving impact resistance may not be sufficient.

The α-olefin component unit constituting the ethylene/d-olefin copolymer (C) is an α-olefin having 3 or more carbon atoms, particularly about 3 to 18 carbon atoms, such as propylene, ■-butene, ■-hexene, Examples include 4-methyl-1-pentene and 1-decene, and they are one kind or a mixture of two or more kinds thereof. Among these, α-olefins having 4 or more carbon atoms are preferred. The ethylene
The α-olefin copolymer is usually a copolymer of an ethylene component and an α-olefin, but in some cases it may contain a trace amount, for example, 0.5 mol % or less, of a diene component.

Examples of unsaturated carboxylic acids or derivatives thereof include acrylic acid, methacrylic acid, maleic acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadic acid (endocys-bicyclo(2,2,
1) unsaturated carboxylic acids such as hept-5-ene-2,3-dicarboxylic acid, or derivatives thereof, such as acid halides, amides, imides, anhydrides, esters, etc.
Specifically, methyl acrylate, methyl methacrylate,
Malenyl chloride, maleimide, maleic anhydride, citracone anhydride, monomethyl maleate, dimethyl maleate,
Examples include glycidyl maleate. Among these, anhydrides are preferred, with maleic anhydride and nadic anhydride (2) being particularly preferred.

The grafting ratio of the graft monomer of the modified ethylene/α-olefin copolymer (D) used in the present invention is in the range of 0.01 to 5 parts by weight based on 100 parts by weight of the ethylene/α-olefin copolymer. The content is preferably in the range of 0.1 to 4 parts by weight. If the grafting ratio of the graft monomer is less than 0.01 parts by weight, the effect of improving impact resistance will be reduced.

Furthermore, if the grafting ratio exceeds 5 parts by weight, the degree of crosslinking of the graft modified product increases, and the effect of improving the impact resistance of the propylene polymer composition decreases. Furthermore, the melt flow rate of the modified ethylene/α-olefin copolymer (D) ('M F'R, A S T M D 12
38°L) is usually in the range of 0.01 to 20 g/10 min, preferably 0.05 to 10 g/10 min.

A graft monomer selected from unsaturated carboxylic acids or derivatives thereof is used as an ethylene/α-olefin copolymer (C).
Various conventionally known methods can be used to graft copolymerize. For example, there is a method in which the ethylene/α-olefin copolymer (C) is melted or dissolved in a solvent, and a graft monomer is added to carry out graft polymerization.

During the graph l-polymerization, other hynyl monomers such as styrene may also be present. A modified ethylene/α-olefin polymer (D) obtained by efficiently performing graft polymerization using a radical generator in It is suitable for this purpose as it has little decomposition. Examples of radical generators include organic peroxides, organic besesters, such as hensyl peroxide 1-, dichlorobenzoyl peroxide 1, dicumyl peroxide, diter
t-Butyl peroxide, 2,5-dimethyl-2,5-
Di(peroxide benzoate) hexyne-3,1,4
-bis(tert-butylperoxyisopropyl)
Benzene, lauroyl peroxide, tert-phthylberacetate, 2,5-dimethyl-2,5-di(te
tert-butylperoxy)hexane-3,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylperbenzoate, tert
tert-butyl perphenylacetate, tert-butyl perisobutyrate, tert-butylperu 5ec
-octoate, tert-butyl perpivalate, cumyl perpivalate and tert-butyl perdiethyl acetate, as well as other azo compounds such as azobisisobutyronitrile, dimethylazoisobutyrate. Among these are dicumyl peroxide, diter
t-Butyl peroxide, 2,5-dimethyl-2,5-
di(tert-butylperoxy)hexyne-3,2,
Dialkyl peroxides such as 5-dimethyl-2,5-di(tert-butylperoxy)hexane and 1,4-bis(tert-butylperoxyisopropyl)benzene are preferred.

In the propylene polymer composition of the present invention, the propylene polymer (A) contains 98 to 49% by weight, preferably 93 to 53% by weight, and the powdery inorganic filler (B) contains 1 to 5% by weight.
0% by weight, preferably 2 to 45% by weight and 1 to 50% by weight of modified ethylene/α-olefin copolymer,
It preferably comprises 2 to 45% by weight. If the amount of powdered inorganic filler (B) is less than 1% by weight, surface hardness, rigidity, heat distortion temperature, etc. will not be improved, while if it exceeds 50% by weight, it will become brittle and therefore not practical.

In addition, the modified ethylene/α-olefin copolymer (D) is
If it is less than 50% by weight, impact resistance will not be improved, and if it exceeds 50% by weight, surface hardness, rigidity, heat distortion temperature, etc. will decrease.

In order to obtain the propylene polymer composition of the present invention, the propylene polymer (A), the powdered inorganic filler (B) and the modified ethylene/α-olefin copolymer (D) can be prepared by various known methods within the above ranges. For example, by mixing with a Henschel mixer, ■-blender, ribbon blender, tumbler blender, etc., or after mixing, by melting and mixing with a screw extruder, twin-screw extruder, kneader, Banbury mixer, etc.
A method of granulation or pulverization may be adopted.

The propylene polymer composition of the present invention contains heat stabilizers, weather stabilizers, antistatic agents, lubricants, slip agents, nucleating agents, pigments or dyes, glass fibers, potassium titanate whiskers, carbon fibers, carbon black, etc. Reinforcing materials and the like may be added within a range that does not impair the purpose of the present invention.

Further, unmodified polyolefin may be blended within a range that does not impair the purpose.

The propylene polymer composition of the present invention has excellent impact resistance etc. compared to conventional compositions consisting of a propylene polymer, a powdered inorganic filler, and ethylene/propylene rubber. It can be molded by extrusion molding or the like and suitably used for automobile parts, industrial parts, parts for home appliances, etc.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these examples in any way as long as the gist thereof is not exceeded.

Example 1 VFR of propylene polymer (A) is 15.8 g/1
0mln, 85% by weight of a block copolymer with an ethylene content of 12 mol%, and talc (trade name Micron White 5000I') as a powdered inorganic filler (B).

Hayashi Kasei, 10% by weight of average particle size 4μ) and modified ethylene/α-olefin copolymer (1)), X-ray crystallinity 17%, ethylene content 90 mol%, maleic anhydride graft amount 0. 47 g / 100 g base polymer, V F R2,5 g / 10 m1n modified ethylene.
5% by weight of 1-butene copolymer (A)+ (B)+
(D) = 100 parts by weight, tetrakis[methylene (3,5-di-tert-butyl-4
-Hydroxy)hydrocinnamate comethane 0.05
Part by weight, 0.1 part by weight of 2,5-di-tert-butyl-4-hydroxytoluene, and 0.1 part by weight of calcium stearate as a hydrochloric acid absorbent were mixed in a Henschel mixer, and then mixed at a resin temperature of 250°C using a 40 mmφ extruder. A propylene polymer composition was obtained by melt-kneading. Next, the composition was injection molded using 15-50 manufactured by Toshiba Machine Co., Ltd. under conditions of a resin temperature of 250°C and a mold temperature of 50°C.

The obtained molded product was evaluated by the following method.

Bending test; bending stiffness FM according to ASTM D790
(kg/c111) and bending strength FS (kg/d
+ ) was completed.

Izot impact strength: 23 according to ASTM D256
A notched IZ (kg-cm 7cm) was placed at -10°C and -10°C.

Dropping impact strength: At -10°C, the weight of a fixed-shaped weight was changed from a height of 7 Qcm on a test piece (12 x 13 x O, 2 cm) placed horizontally, and 50% of a certain number of test pieces were broken. The impact strength F D (kg-cm) was calculated based on the energy required to do so.

Heat distortion temperature; 18.6 according to ASTM 064B
kg/C - HDT under load ("C) was calculated.

Surface Hardness i Rockwell hardness, R scale, according to ASTM 0785.

The results are shown in Table 1.

Example 2.3 The propylene polymer (A), powdered inorganic filler (B), and modified ethylene/α-olefin copolymer (D) used in Example were mixed in the proportions shown in Table 1. The same procedure as in Example (2) was carried out. The results are shown in Table 1.

Example 4 Propylene polymer (A), powdered inorganic filler (B), modified ethylene/α-olefin copolymer (D) used in Example 1, crystallinity 5%, ethylene content 80%, M
The same procedure as in Example 1 was carried out except that 1 g/10 ml of ethylene/propylene copolymer was mixed in the proportions shown in Table 1. The results are shown in Table 1. , /' -1-11--11 Example 5 Instead of the propylene polymer (A) used in Example I,
Example 1 except that a propylene homopolymer with a VFR of 9.50 g/10 m1n was used and mixed in the proportions shown in Table 1.
I did the same thing. The results are shown in Table 1.

Example 6 The propylene polymer (A), powdered inorganic filler (B), modified ethylene/α-olefin copolymer (D) used in Example 5 and the density 0, 956 g/co! .

Butene-1 content 2.5mol1%, M F R2, 42g
The same procedure as in Example 5 was carried out except that 10ml/1n of high-density polyethylene was mixed in the proportions shown in Table 1. The results are shown in Table 1.

Example 7.8 The same procedure as in Example 3 was carried out except that the talc used in Example 3 and glass fiber or potassium titanate whiskers (manufactured by Ogaki Chemicals, Teismo D) were used in combination. The results are shown in Table 1.

Example 9 Instead of the modified ethylene/l-butene copolymer used in Example 2, crystallinity by X-rays was 6% and ethylene content was 8.
0 mol%, maleic anhydride graft amount 0.44 parts by weight,
The same procedure as in Example 2 was carried out except that a modified ethylene/propylene copolymer of MFR1,51g/10ml was used. The results are shown in Table 1.

Comparative Example 1.2 Instead of the modified ethylene/1-butene copolymer used in Examples 3 and 5, an untreated polymer with an X-ray crystallinity of 18%, an ethylene content of 90 mol%, and a VFR of 3.1 g/lOmjn was used. The same procedure as in Example 3 and Example 5 was carried out except that the modified ethylene/]-butene copolymer was used. The results are shown in Table 1. ′− /−12 ′ //′ /−/ /゛7−/

Claims (1)

[Claims] (98 to 49% by weight of 11 propylene polymer (A),
Powdered inorganic filler (B) 1 to 50% by weight, X-ray crystallinity 0 to 50% and ethylene content 55
to 95 mol% of ethylene/α-olefin copolymer (C) 0.01 to 5 parts by weight of a graft monomer selected from unsaturated carboxylic acids or derivatives thereof
A propylene polymer composition comprising 1 to 50% by weight of a graft-modified ethylene/α-olefin copolymer (D).