JPS61190540A - Modification of polypropylene resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled modified composition free from generation of residual odor, causing no coarse surface with improved mechanical strength, suitable for use in automobile sector, etc., by incorporating polypropylene resin with organic peroxide and glycerin fatty acid ester as a crosslinking promotor. CONSTITUTION:The objective composition can be obtained by incorporating (A) 100pts.wt. of polypropylene resin composition with (B) 0.01-1(pref. 0.02-0.1)pt.wt. of an organic peroxide (e.g., benzoyl peroxide) and (C) 0.01-5(pref. 0.02-0.8)pts.wt. of a glycerin fatty acid ester as a crosslinking promotor (e.g., glycerol monomethacrylate, glycerol dimethacrylate) so as to be 3-20 (pref. 5-15) in the weight ratio (B)/(C).

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for modifying a polypropylene resin composition,
More specifically, it is a modified polypropylene resin composition that does not cause deterioration in surface appearance even when subjected to modification treatment, has no residual odor from the crosslinking aid used, and has improved mechanical strength such as rigidity and impact strength. Concerning how things can be obtained.

[Technical Background of the Invention and Problems Therein] Efforts have been made to improve the rigidity and impact strength of polypropylene resin compositions by modifying them with organic peroxides and crosslinking aids. (See Japanese Patent Application Laid-Open No. 58-187412 and Japanese Patent Application Laid-Open No. 59-93709).

However, in the conventional modification method disclosed herein, although it is true that the mechanical strength properties of the modified polypropylene resin composition are improved, on the other hand, the crosslinking aid used is divinylbenzene, paraquinone divinylbenzene, Oxime, phenylmaleimide, etc. have a strong residual odor, and furthermore, the surface appearance of the modified polypropylene resin composition deteriorates significantly compared to that before modification, which poses problems in terms of practicality in various application fields. is occurring.

[Purpose of the invention] The present invention is a conventional modification of polypropylene resin compositions.

We have developed a new modification method that solves the above-mentioned problems in the manufacturing method and improves mechanical strength properties, but also does not generate residual odor or cause any deterioration of surface appearance. For the purpose of providing.

[Summary of the Invention] The present inventors have conducted extensive research to achieve the above object, and
After various searches and studies regarding the crosslinking aid to be used, it was discovered that the fatty acid ester of glycerin (glyceride) described below is extremely effective, leading to the development of the modification method of the present invention.

That is, the method for modifying a polypropylene resin composition of the present invention is a method for modifying a polypropylene resin composition with an organic peroxide and a crosslinking aid, characterized in that the crosslinking aid is a fatty acid ester of glycerin. do.

First, the polypropylene resin composition to which the method of the present invention is applied includes, for example, a single resin such as a polypropylene homopolymer, a propylene-ethylene copolymer, or a mixture thereof; or a single resin (or a mixture thereof). A resin composition comprising an elastomer such as ethylene-propylene rubber is included.

Next, as the organic peroxide, known ones can be used, such as benzoyl peroxide, diglorbenzoyl peroxide, dicumyl peroxide, di-t-
Butyl peroxide, 2,5-dimethyl-2,5-di (peroxide benzoate) hexyne-3,1,3
-Bis(t-butylperoxyisopropyl)benzene, lauroyl peroxide.

t-Butyl peracetate, 2,5-dimethyl-2,5
-di(t-butylperoxy)hexyne-3,2,5-
Dimethyl-2,5,-di(t-butylperoxy)hexane, 1-butyl perbenzoate, t-butyl perphenylacetate, t-butyl perisobutyrate,
Examples include t-butyl per5ec-octate, t-butyl perpivalate, cumyl perpivalate, and t-butyl perdiethyl acetate. Among these, 1,3-bis(t-butylperoxyisopropyl)benzene, dicumyl peroxide, di-1-butylperoxide, 2,5-dimethyl-2,5-di(1-butylperoxy)hexyne -3,2,5-dimethyl-2,
5-di(t-butylperoxy)hexane and the like are preferred.

These organic peroxides are used in polypropylene resin composition 1.
0.01 to 1.0 parts by weight per 00 parts by weight. If the blending amount is less than 0.01 part by weight, the improvement in mechanical strength properties will be insufficient, and if it exceeds 1.0 parts by weight, the polypropylene resin will undergo many molecular breaks, resulting in the overall mechanical strength. properties deteriorate. Preferably 002~
It is 0.11 parts by weight.

The crosslinking aid in the method of the invention is a fatty acid ester of glycerin. The fatty acid ester of glycerin used may be any of molyglyceride, diglyceride, and triglyceride, and the fatty acid to be esterified and bonded to these glycerides may have an alkyl group or alkenyl group having 1 to 50 carbon atoms as a backbone. Examples include monovalent saturated fatty acids or aphasic fatty acids.

Specific examples of such crosslinking aids include glycerol monomethacrylate, glycerol dimethacrylate, and glycerol methacrylate.

Glycerol methacrylate alkylate or glycerol methacrylate alkylate represented by the following formula: % (wherein R represents an alkyl group or alkenyl group having 1 to 50 carbon atoms) can be mentioned.

Each of these may be blended alone, or two or more types may be blended in an appropriate combination, in which case the blending amount is approximately 0.01 to 5 parts by weight per 100 parts by weight of the polypropylene resin composition. .0 parts by weight. The blending amount is 0.
If the amount is less than 0.01 parts by weight, the effect as a crosslinking aid will not be fully exhibited, and if it is added in excess of 5.0 parts by weight, no improvement in mechanical strength properties will be obtained, so it is meaningless. It is. Preferably, it is 0.02 to 0.8 parts by weight.

The blending ratio of the organic peroxide and the crosslinking aid is 3 to 20% by weight (organic peroxide/crosslinking aid). Preferably 5~
It is set to 15. This is because when this ratio is less than 3, the crosslinking phenomenon does not progress to a significant degree, and when it exceeds 20, the crosslinking aid remains, resulting in a decrease in the mechanical strength characteristics of the resulting modified resin composition.

The method of the present invention is carried out as follows.

That is, a predetermined amount of an organic peroxide and a crosslinking aid may be blended into the polypropylene resin composition to be modified as described in detail above, and the R compound may be melt-kneaded after sufficiently stirring and mixing.
The temperature applied during this melting and cross-wiring is 190 to 260℃.
, preferably 200 to 250°C. Temperature is 190℃
If it is lower, the mechanical strength characteristics of the modified resin composition will not improve, and if it is higher than 260°C, decomposition will occur more favorably than crosslinking during melt mixing, which is not preferable.

The time for performing melt crossing is 0.5 to 10 minutes, preferably 1
~5 minutes. If this time is shorter than 0.5 minutes, the decomposition of the blended organic peroxide will not be completed, and if it is longer than 10 minutes, molecular cleavage due to shearing will proceed excessively, resulting in poor mechanical strength properties after modification. In particular, this results in a decrease in impact strength.

[Examples of the Invention] Examples 1 to 5 Four types of polypropylene resins whose molded articles had the characteristics shown in Table 7iIJ1 were prepared. These are the target resins to be modified.

Table 1 Zero 1: Compliant with JISK7203 Clothes 2: Using a melt tension tester made by Toyo Seiki, from an orifice with a diameter of 2.09 m and a length of 8 cm, 2
Each resin in Table 1 heated to 30° C. was extruded at a speed of 20 σ in, the extrudate was passed through a tension sensing pulley, and the extrudate was wound at a speed such that the pulley rotated at 20 rpm. Advantage 3 of the tension that acts when taking the sample: 1,3-bis (tertiary-butylperoxy) isopropylbenzene and 2 digimyl peroxide were prepared as organic peroxides in accordance with JIS K7110.

Furthermore, as a crosslinking aid, a, glycerol methacrylate acrylate, b, glycerol dimethacrylate,
C, divinylbenzene, d, baraquinone dioxime, e
, phenylmaleimide was prepared.

The above components were mixed in the proportions (parts by weight) shown in Table 2, and further stirred and mixed using a super floater to obtain a uniform composition. Each of these compositions was pelletized using an axle extruder, and the pellets were injection molded to give test pieces of a predetermined shape.

For each test piece obtained, the flexural modulus, melt tension, and Izod impact strength were measured in the same manner as above, and the surface appearance and residual odor were also examined.

The above results are collectively shown in Table 2. Note that the characteristic values in Table 1 are ratios to the characteristic values of each polypropylene resin shown in Table 1.

Examples 6 to 7 Examples 1 to 7 except that the composition shown in Table 3 was used in place of the polypropylene resin used in Examples 1 to 5.
A test piece was manufactured in the same manner as in Example 5.

That is, after mixing a predetermined amount of polypropylene resin and ethylene-propylene rubber shown in Table 3 and granulating the mixture using an axle extruder, organic peroxide and crosslinking agent were added to the resulting pellets in the proportions shown in Table 4 ( (parts by weight) and further stirred and mixed using a super floater to obtain a homogeneous composition. Each of the compositions was pelletized using an axle extruder and then injection molded to obtain a test piece.

The properties of the obtained test pieces were investigated using the same specifications as in Examples 1 to 5, and the results are summarized in Table 4.

[Effects of the Invention] As is clear from the above explanation, when the method of the present invention is applied, the modified polypropylene resin composition has both improved rigidity and impact strength compared to before modification, and There is no residual odor, and the surface appearance is the same as before modification. Therefore, the polypropylene resin composition modified by the method of the present invention is useful as a material for automobiles, light electrical equipment, etc., extruded sheets, films, and blow molding.

Procedural amendment February 9, 1988 Michibe Uga, Commissioner of the Patent Office 1, *n indication 1985 Patent Application No. 30267 2, Title of invention Method for modifying polypropylene resin composition 3, Amendments made Relationship with patent applicant Name of patent applicant Idemitsu Petrochemical Co., Ltd. 4, Agent 5, Date of amendment order Voluntary action 6, Subject of amendment Column 7 for detailed explanation of the invention in the specification, Contents of amendment'... ′・t′ ji,”l.

(1) [Deterioration phenomenon of surface appearance] described in lines 12 and 13 of page 1 of the specification is corrected to ``surface roughness such that many shark-skin-like irregularities occur on the surface.''

(2) "Appearance" stated in the 8th line of page 2 of the specification is deleted.

(3) "Deteriorated" stated in the 9th line of page 2 of the specification is replaced with "
"It's rough," he corrected.

(4) "Surface appearance deterioration phenomenon" stated in the 15th line of page 2 of the specification is corrected to "surface roughness."

(5) "Moriglyceride" stated on page 5, line 5 of the specification is corrected to "monoglyceride."

(6) "Surface appearance" described in lines 5 and 6 on page 15 of the specification is corrected to "surface roughness."

Claims (1)

[Claims] A method for modifying a polypropylene resin composition with an organic peroxide and a crosslinking aid, wherein the crosslinking aid is a fatty acid ester of glycerin.