JPH06322195A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:To provide a polypropylene resin composition having excellent dispersibility of nucleation agent and improved transparency. CONSTITUTION:The polypropylene resin composition is composed of 80-100 pts.wt. of a polypropylene, 0.005-3.0 pts.wt. of a nucleation agent consisting of an aromatic phosphoric acid compound metal salt and 2-20 pts.wt. of an aliphatic or an alicyclic hydrocarbon resin having a softening point of 70-160 deg.C. Since the aliphatic or alicyclic hydrocarbon resin is used in combination with the nucleation agent consisting of a metal salt of an aromatic phosphoric acid compound, the composition has excellent dispersibility of the nucleation agent and improved transparency. Accordingly, the composition can be used for packaging material, container, etc.

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 used for films, sheets, molded articles and the like, and more particularly to a polypropylene resin composition excellent in transparency and moldability. Is.

[0002]

2. Description of the Related Art Polypropylene is widely used as a packaging material, sundries, and industrial parts because it has high strength for its specific gravity, excellent heat resistance, and is inexpensive. However, polypropylene has a drawback that it is inferior in transparency to polystyrene or vinyl chloride resin due to crystals formed during or after molding, and its application is often limited.

In order to eliminate such drawbacks, various transparency improving agents have hitherto been proposed. Examples of these transparency improving agents include inorganic nucleating agents such as talc, metal salts of aliphatic carboxylic acids, aluminum salts of aromatic carboxylic acids, dibenzylidene sorbitols, and metal salts of aromatic phosphate compounds. There is known a method of adding an organic nucleating agent such as JP-A-55-16004, JP-A-56-45934, JP-A-56-62843, JP-A-58-165858, and JP-A-58-165858. Sho 58-25341
No., Japanese Examined Sho 63-8980).

All of these nucleating agents are not sufficiently effective, and moreover, many of them accelerate deterioration of the resin or lower mechanical strength, which are not practically satisfactory. A polypropylene resin composition to which a sorbitol-based nucleating agent is added has a bad odor, and has a brittle appearance during molding.
There were some drawbacks.

Regarding the metal salt type nucleating agent of an aromatic phosphoric acid compound, the effect of improving the transparency is insufficient, and the compatibility and dispersibility with respect to polypropylene are insufficient, and the dispersion in the molded product is visually observed. It could be confirmed at.

Further, a method in which a sorbitol-based nucleating agent is used in combination with a hindered phenol-based or aromatic phosphorus-based antioxidant (JP-A-4-153240), and a phosphorus-based compound metal salt (nucleating agent) The method of adding a thermoplastic elastomer and an organic peroxide to a heat treatment (Japanese Patent Laid-Open No. 4-216841) has been proposed, but in these methods, transparency and dispersibility of the nucleating agent are proposed. Is still insufficient.

Further, in JP-A-4-23843, a method of blending a nucleating agent and a hydrogenated coumarone indene resin is known, but there is only an example of a sorbitol-based nucleating agent, and in this case There is still room for improvement in some cases.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polypropylene resin composition having excellent dispersibility of a nucleating agent and improved transparency.

[0009]

Therefore, the present inventor conducted research to solve the above-mentioned problems, and blended polypropylene with a metal salt-based nucleating agent of an aromatic phosphoric acid compound and further softening point 70 The inventors have found that a composition containing an aliphatic or alicyclic hydrocarbon resin at ˜160 ° C. has excellent dispersibility of the nucleating agent and improved transparency, and completed the present invention.

That is, the present invention relates to polypropylene 80-
From 100 parts by weight, a metal salt-based nucleating agent of an aromatic phosphoric acid compound 0.005 to 3.0 parts by weight, and an aliphatic or alicyclic hydrocarbon resin having a softening point of 70 to 160 ° C. from 2 to 20 parts by weight The polypropylene resin composition has excellent dispersibility of the nucleating agent and has improved transparency.

The polypropylene used in the present invention is homopolypropylene or a random copolymer of propylene and an α-olefin such as ethylene or butene-1.

The metal salt nucleating agent of an aromatic phosphoric acid compound used in the present invention is a compound as disclosed in JP-B-63-8980, more preferably sodium-2,2.
-Methylene-bis- (4,6-di-t-butylphenyl) phosphate, sodium-2,2-ethylidene-bis- (4,6-di-t-butylphenyl) phosphate, lithium-2 , 2-methylene-bis- (4,6
Examples thereof include -di-t-butylphenyl) phosphate and lithium-2,2-ethylidene-bis- (4,6-di-t-butylphenyl) phosphate.

In particular, sodium-2,2-methylene-bis- (4,6-di-t-butylphenyl) phosphine
Are more preferable than other nucleating agents in improving transparency and impact resistance, and known ones can be used. Further, the particle size is preferably 50 μm or less, and particularly 30 μm or less,
More preferable.

The blending ratio of the aromatic salt phosphoric acid compound metal salt nucleating agent used in the present invention is 0.005 to 3.0 parts by weight based on 80 to 100 parts by weight of polypropylene. 0.0
If the amount is less than 05 parts by weight, the transparency improving effect will not be obtained, and if the amount is more than 3.0 parts by weight, the transparency improving effect will not be improved.

The aliphatic or alicyclic hydrocarbon resin used in the present invention has a softening point of 70 to 160 ° C. Molecular weight is 400
Those of up to 5000 are preferred. If the softening point is lower than 70 ° C, the composition containing the softening point may have poor heat discoloration resistance, smoke may be generated during melt processing, and the surface of the molded article may be sticky. If it exceeds 150 ° C, the effect of improving the transparency and the like becomes insufficient, and it becomes difficult to dissolve it in the composition.

The amount of the aliphatic or alicyclic hydrocarbon resin used in the present invention is preferably 2 to 20 parts by weight with respect to 80 to 100 parts by weight of polypropylene. When it is less than 2 parts by weight, the effect of improving transparency and nucleating agent dispersibility cannot be obtained, and when it is 20 parts by weight or more, the physical properties of the resin composition deteriorate.

Examples of usable resins include hydrogenated coumarone / indene resin, hydrogenated C9 petroleum resin, hydrogenated C5 petroleum resin, hydrogenated terpene resin and hydrogenated rosin resin. Hydrogenated C9 petroleum resins are preferred.

The hydrogenated coumarone-indene resin used in the present invention is a resin containing coumarone, indene or an alkylindene derivative, phenol or an alkylphenol derivative as an essential constituent monomer in the raw material resin. Accordingly, a gas oil produced during coal carbonization or a desulfurized refinement of a 130 to 200 ° C. fraction obtained by distillation of a coal can be used as a feedstock. The composition of the monomer in the raw material resin is coumarone: 1 to 10% by weight, indene or alkylindene derivative: 60 to 8
0% by weight, phenol or alkylphenol derivative: 1 to 15% by weight is preferred.

The hydrogenation ratio of the hydrogenated coumarone / indene resin used in the present invention is 80% or more, preferably 95%.
% Or more is preferable. If the hydrogenation rate is less than 80%, the polypropylene composition containing the resin has poor heat discoloration resistance and tends to yellow due to the heat history during molding.

The hydrogenated C9 petroleum resin used in the present invention is
Known ones can be used. Specifically, for example, an aromatic petroleum resin obtained by polymerizing a unit monomer represented by vinyltoluene, vinylxylene, styrene, α-methylstyrene, para-methylstyrene, indene, methylindene, ethylindene, etc. Examples include hydrogenated products.

Hydrogenated C9 used for the purposes of the present invention
Hydrogenation rate of petroleum resin is 80% or more, preferably 9
5% or more is preferable. If the hydrogenation rate is less than 80%,
A polypropylene composition containing a resin has poor heat discoloration resistance and tends to yellow due to heat history during molding.

The composition of the present invention may contain a stabilizer, if necessary.
Various additives which are usually added to polypropylene, such as an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, and a surfactant, can be added within a range that does not impair the transparency.

In the present invention, the method of mixing the above components is not particularly limited, and the components are simply thoroughly mixed with a Henschel mixer or the like, and then the melting point of polypropylene or higher, generally, the melting point to 260 ° C. or lower. It may be carried out by a method of melt-kneading at a temperature.

[0024]

[Function] The compatibility (dispersibility) of the metal salt type nucleating agent of an aromatic phosphoric acid compound with polypropylene has a softening point of 70 to 160 ° C. by blending an aliphatic or alicyclic hydrocarbon resin, Since it was remarkably improved, it is considered that the dispersibility and transparency of the nucleating agent are excellent.

[0025]

【Example】

Example. 1 Sodium-2,2-methylene-bis- (4,6) in 96 parts by weight of polypropylene (RB410, Tokuyama Soda Co., Ltd.)
-Di-t-butylphenyl) phosphate (Adeka Stab NA-11, Asahi Denka Co., Ltd.), a softening point of 100 ° C. obtained by hydrogenating a coumarone indene resin having the constituent monomer composition shown in Table 1. 4 parts by weight of hydrogenated coumarone indene resin with a hydrogenation rate of 99%, an antioxidant (Ciba-Geigy-
Co., Ltd., Irganox 1010) was used and mixed at the compounding ratio shown in Table 2. 30 for the above mixture at the set temperature
The polypropylene resin composition was pelletized by kneading and extruding with a mmφ twin-screw extruder.

[0026]

[Table 1]

[0027]

[Table 2]

The polypropylene resin composition was injection-molded at a cylinder temperature of 220 ° C. and an injection pressure of 50 kg / cm ² .
A test piece of 40 mm × 60 mm × 1.2 mm was obtained. The appearance of this test piece was observed to confirm the dispersed state of the nucleating agent. In addition, the haze (HAZE%) measured by Haze meter (Nippon Denshoku Industries)
(JIS-K6714) was measured. The results are shown in Table 3. Further, the polypropylene resin composition was injection-molded under the same conditions to obtain a test piece for Izod impact test, and an impact test (JIS-K7110) was performed. The results are shown in Table 3.

Example. 2 except that 93 parts by weight of polypropylene and 7 parts by weight of hydrogenated coumarone / indene resin were mixed and mixed at the compounding ratios shown in Table 2, all of the examples. A test piece was obtained in the same manner as in 1.
The results are shown in Table 3.

Example. 3 Change hydrogenated coumarone indene resin to hydrogenated C9 petroleum resin (Arakawa Chemical Industry Co., Ltd., Alcon P100),
Except that the mixing ratios shown in Table 2 were used, all of the examples. 1
A test piece was obtained in the same manner as in. The results are shown in Table 3.

Example. 4 except that polypropylene was changed to 93 parts by weight and hydrogenated C9-based petroleum resin was changed to 7 parts by weight, and the mixing ratios shown in Table 2 were mixed,
All examples. A test piece was obtained in the same manner as in 3. The results are shown in Table 3.

[0032]

[Comparative example]

Comparative example. Example 1 except that the metal salt nucleating agent of the aromatic phosphoric acid compound and the hydrogenated coumarone indene resin were not included and mixed at the compounding ratio shown in Table 2. A test piece was obtained in the same manner as in 1.
The results are shown in Table 3. The transparency (haze) was inferior to the examples.

Comparative Example. 2 Hydrogenated coumarone indene resin was not included, and all were mixed in the mixing ratios shown in Table 2, except that the composition of Example. A test piece was obtained in the same manner as in 1. The results are shown in Table 3. In the molded product, a powder of a nucleating agent that was incompatible with polypropylene was confirmed, and the transparency (haze) was inferior to that of the example.

Comparative Example. Example 3 except that polypropylene was 99 parts by weight and hydrogenated coumarone indene resin was 1 part by weight, and the mixing ratios shown in Table 2 were used. A test piece was obtained in the same manner as in 1. The results are shown in Table 3. Nucleating agent powder that is not compatible with polypropylene was confirmed in the molded product, and transparency (haze)
Was inferior to the examples.

Comparative Example. Example 4 except that 70 parts by weight of polypropylene and 30 parts by weight of hydrogenated coumarone indene resin were mixed at the compounding ratios shown in Table 2 A test piece was obtained in the same manner as in 1.
The results are shown in Table 3. The dispersibility of the nucleating agent was good,
The moldability of the molded product deteriorated.

Comparative Example. 5 Polypropylene was 99 parts by weight, hydrogenated C9 petroleum resin was 1 part by weight, and all were mixed in the mixing ratios shown in Table 2 in Example. A test piece was obtained in the same manner as in 1. The results are shown in Table 3.
It was shown to. A powder of a nucleating agent that was not compatible with polypropylene was confirmed in the molded product, and the transparency (haze) was inferior to that of the example.

Comparative Example. 6 except that polypropylene was 70 parts by weight and hydrogenated C9 petroleum resin was 30 parts by weight, and the mixing ratios shown in Table 2 were used.
All examples. A test piece was obtained in the same manner as in 1. The results are shown in Table 3.

[0038]

[Table 3]

The dispersibility of the nucleating agent was good, but the moldability of the molded product was poor.

[0040]

EFFECT OF THE INVENTION The polypropylene resin composition obtained by the present invention has excellent transparency and can be applied to packaging materials, containers and the like.

Claims (2)

[Claims] 1. A polypropylene salt of 80 to 100 parts by weight, a metal salt type nucleating agent of an aromatic phosphoric acid compound of 0.005 to 3.0 parts by weight, and an aliphatic or alicyclic hydrocarbon resin of a softening point of 70 to 160 ° C. A polypropylene resin composition comprising 20 parts by weight. 2. A metal salt-based nucleating agent of an aromatic phosphoric acid compound,
Sodium-2,2-methylene-bis- (4,6-di-
The polypropylene resin composition according to claim 1, which is t-butylphenyl) phosphate.