JPS6049048A - Impact-resistant polypropylene resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition of markedly improved impact resistance with enhanced gloss and elongation, by incorporating polypropylene resin with calcium carbonate surface-modified with a mixture of higher fatty acid and its ester. CONSTITUTION:The objective composition can be obtained by incorporating (A) a polypropylene resin with (B) calcium carbonate (of an average size 0.3-1.1mu) which is surface-modified with a mixture of a higher fatty acid and its ester in a ratio 10:90-90:10 (pref. 50:50). Said mixture should be used 2.0-9.0 in wt% based on the original calcium carbonate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inorganic-filled polypropylene resin composition having improved 1J impact resistance, heat resistance, gloss and elongation. In particular, the object is to provide a material with remarkable improvement in impact resistance.

Traditionally, polypropylene resin has been widely filled with inorganic substances such as talc, asbestos, and calcium carbonate to improve rigidity, heat resistance, and dimensional stability. is weak, resulting in a significant drop in impact strength. In order to improve these drawbacks, methods have been used such as coating the surface of the inorganic filler with surfactants, etc., or polymerizing other components with polypropylene by graft polymerization to increase the affinity with the filler. . On the other hand, attempts have been made to increase the contact area with polypropylene by using calcium carbonate with a small particle size and therefore a large specific surface area, thereby improving various physical properties to some extent. The smaller the particle size, the more difficult it is for calcium carbonate to aggregate and disperse uniformly in the resin. Also, the smaller the particle size, the larger the surface area, so there will be more adsorbed and attached water, and if the particle size is 0.3μ or less, The amount of moisture such as adsorbed water and attached water is as much as 0.6 to 1.2%, and this moisture evaporates during kneading with polypropylene, resulting in many product defects and making it difficult to use.

In order to eliminate the above-mentioned drawbacks, the present invention has been made based on various studies on filler addition techniques that do not require much effort or cost even when a large amount of filler is added, and do not reduce physical properties. By selecting the particle size of calcium carbonate and the type and combination of surface treatment agents, the above-mentioned drawbacks can be solved, resulting in improved impact resistance and heat resistance.

The gloss and workability were significantly improved, and we discovered remarkable effects that could not be expected from the single addition of conventional surface treatment agents.
This completes the present invention.

The gist thereof is an impact-resistant polypropylene resin composition containing calcium carbonate whose surface has been modified with a mixture of a higher fatty acid and a higher fatty acid ester, and more specifically, a particle size of 0.3 to 1. Higher fatty acids and higher fatty acid esters are each added to 1μ of calcium carbonate from 90 to 10%.
A mixture of 2.0 to 9.0 in the range of 10 to 90
Calcium carbonate-containing polypropylene with improved impact resistance, heat resistance, elongation and gloss and good workability, consisting of 10 to 50 parts by weight of calcium carbonate surface-treated and 50 to 90 parts by weight of polypropylene resin. It is a type resin composition.

The higher fatty acids used in the present invention are those whose main components are C12 to G20, which are generally called higher fatty acids, and higher fatty acid esters.

It is an ester of a monohydric alcohol with a mixture of two higher fatty acids or alone. For example, methyl palmitate, butyl dianthate, etc. 4 Surface modification of such higher fatty acids and higher fatty acid esters @JJk compared to calcium carbonate The impact resistance of the product is not significantly improved, and when the amount added is 9 parts by weight, the softening effect is large and the general physical properties and impact resistance are deteriorated.

Higher fatty acids and higher fatty acid esters have been investigated as modifiers for calcium carbonate, but until now they have been recognized as belonging to a category that is not very effective. However, they have discovered that the modification effect of calcium carbonate is significantly improved when treated with a mixture of higher fatty acids and higher fatty acid esters.

As mentioned above, from the mixed ratio number of both, 0:10~
Effective in a wide range of 10:90, especially 200:
20-20: Remarkable performance improvement at 80, 50
: The maximum value can be obtained around 50.

For example, calcium carbonate treated with varying mixing ratios from a single main treatment of a complex higher fatty acid with a CI of 8+ + 8 to a single treatment of a complex higher fatty acid ester of the same FIG. 1 shows the Izot impact strength of 30 parts added to MI=4 and MI=7). In addition, other physical properties such as elongation at break and gloss are significantly improved, and thermal deformation temperature and elastic modulus are also slightly improved, resulting in strength.

In this way, it is the higher fatty acids and higher fatty acid esters as surface treatment agents that improve the film properties such as heat resistance and other properties in the present invention. This is presumed to be due to the effective contact effect at the interface with the resin.

According to the present invention, it is possible to obtain a resin composition that has excellent impact resistance, heat resistance, gloss, and elongation, and is easy to work with, so that it can be used easily and inexpensively for general electrical appliance parts, household appliances, etc. .

Next, examples of the present invention will be described.

Example contents: 10θQ ribbon blender with average particle size of 0.8μ
After stirring for about 30 minutes at a temperature of 200°C, 1 kg of stearic acid and 1 kg of a composite ester of methyl palmitate and methyl oleate were added gradually, stirring and heating were continued. was taken out after about 2 hours, and after cooling, it was pulverized with an ultra-fine pulverizer to obtain a surface-modified carbonate resin. The above surface-modified calcium carbonate type 30 side (kneaded for 10 minutes at 190° C. in a mixing mixer was formed into pellets using an extruder).

The pellets were molded into test pieces for measuring grain quality using an injection molding machine 'rS-150 (manufactured by Nippon Steel).

At the same time, general-purpose heavy calcium carbonate (average particle size 1.7 μm) and the above-mentioned untreated calcium carbonate (average particle size 0.8 μm) were mixed under the same conditions and test pieces were prepared as comparison samples. The physical property measurement results are shown in Tables 1 to 3. Moreover, the various physical property values illustrated are measured values based on the following method.

Tensile test; ASTM D-638 Izod 1 to impact strength; ASTM D-256 heat distortion temperature; ASTM D-648 load = 18.6 kg1
0f Glossiness; JIS Z-8741 Heat resistance: Visual observation of thermal discoloration and appearance As is clear from the above examples, the products of the present invention are Izotsu? The value of the lf impact test is based on the block type l]P(MI
4) yields surprising results. Different types of l) P in Tables 2 and 3 are 40% to 150% of PP alone.
This shows an increase in impact strength, indicating that the material is particularly excellent.

It has excellent gloss and heat resistance, and the elongation of tensile properties is also excellent.
It has great features such as strength and excellent performance. .

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the mixing ratio of higher fatty acids and higher fatty acid esters and the impact strength of calcium carbonate-added polypropylene resin modified thereby. I-11 Applicant Bihoku Funka Kogyo Co., Ltd. Agent Patent Attorney Hirozo Mori

Claims (1)

[Scope of Claims] 1. An impact-resistant polypropylene resin composition containing calcium carbonate surface-modified with a mixture of a higher fatty acid and a higher fatty acid ester. The mixing ratio of 2 higher fatty acids and higher fatty acid esters is lO
The impact-resistant polypropylene resin composition according to claim 1, which has a hardness of 90 to 90 to 10. 2. The impact-resistant polypropylene resin composition according to claim 1, wherein the total amount of the higher fatty acid and the higher fatty acid ester is 2.0 to 9.0 parts by weight based on calcium carbonate. The impact-resistant polypropylene resin composition according to claim 1 or 3, wherein the average particle diameter of the calcium tetracarbonate is 0.3 to 1.1 μ.