JPS591741B2 - Polypropylene horns - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving the impact resistance of polypropylene compositions.

Specifically, crystalline polypropylene with a melt index of 10 or less or a propylene-ethylene block copolymer with an ethylene content of 3 to 30 weight and an average particle size of 20
Improving the impact resistance of a composition containing an inorganic filler of less than μ,
The invention also relates to a method for improving rigidity, heat resistance, and dimensional stability. In general, polyolefins are used to improve the rigidity, dimensional stability, heat resistance, hardness, etc. of polyolefins such as polyethylene and polypropylene, to reduce product costs by increasing the amount of polyolefins, and to make them easier to burn during disposal. Inorganic fillers have been added to these materials.

However, when inorganic fillers are added to polyolefins, while the above improvements and modifications are achieved, the impact resistance decreases, and this is a major drawback when adding inorganic fillers in the past. It was one of the.

Adding inorganic fine powders such as talc and silica, and nucleating agents such as aliphatic dibasic acids and aromatic carboxylic acids to crystalline thermoplastic resins promotes the generation of crystal nuclei and produces a large number of nuclei. Therefore, the crystals become finer, which improves the transparency of the resin and improves the crystallization speed, which provides molding benefits such as shortening the molding cycle and reducing the appearance of burrs in injection molding, as well as a high degree of crystallinity. This provides the advantage of improved tensile strength, rigidity, etc.

However, the addition of a nucleating agent has drawbacks such as a significant decrease in elongation and a decrease in ball impact strength.

Attempts to improve impact resistance using inorganic fillers have been made for a long time.

These improvement methods focus on the fact that the elastic modulus of inorganic fillers is higher than that of polymers, and improve impact resistance by filling the composite with inorganic fillers and improving the elastic modulus of composites. It is something. However, in these modulus-dependent improvement methods, in the presence of stress concentrators such as notches and wedges, the impact resistance significantly decreases or becomes non-existent. In order to improve the impact resistance in the presence of stress concentrators, it is required to disperse or alleviate the impact stress.

An object of the present invention is to provide a method for improving the above-mentioned drawbacks and improving the rigidity, dimensional stability, heat resistance, etc. of polypropylene compositions, as well as improving the impact resistance.

It is another object of the present invention to provide a method for shortening molding cycles and other molding benefits and improving tensile strength, stiffness, and impact resistance.

The present invention achieves the above object, and uses a specific nucleating agent of 0.05 to 0.5% by weight. Melt index 10
Is the following crystalline polypropylene or ethylene content 30% by weight? A method for improving impact resistance characterized by blending and kneading the following propylene-ethylene block copolymer into a blend of 30 to 95 inorganic fillers having a weight average particle size of 20 μ or less and 70 to 70 by weight. be.

In the present invention, the reason why the effect of improving impact resistance is expressed by filling the above-mentioned polypropylene with an inorganic filler and a nucleating agent is not necessarily clear, but the improvement in elastic modulus by adding an inorganic filler and the nucleating agent This is thought to be due to a synergistic effect with the improvement in elastic modulus due to the increase in the crystallinity of polypropylene due to the addition of the nucleating agent, and the effect of facilitating the dispersion of impact stress due to the refinement of the spherulites of polypropylene due to the addition of the nucleating agent.

Therefore, the effect of improving impact resistance in the presence of stress concentrators such as notches and wedges is improved to a greater extent than that of the conventional elastic modulus dependence, and furthermore, the effect of improving impact resistance in the presence of stress concentrators such as notches and wedges is further improved.

The filler used in the present invention has an average particle size of 20μ
The following are preferably 0.05 to 5μ of silica, alumina, oxides of various metals other than talc, hydroxides, carbonates, sulfates, silicates, silicate minerals, carbides, ceramics, etc. Typical examples include titanium oxide, zinc oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, calcium sulfate, barium disulfate, calcium sulfite, calcium silicate, magnesium silicate, celite, kaolin, zeolite, carbon black, and titanium. barium oxide, lead titanate, etc., and these may be used alone or as a mixture, preferably 5 to 70% by weight. 10～
40 weight 70 is blended.

It is desirable that the surface of this type of inorganic filler be modified in order to increase its affinity with polypropylene.

Surface-hydrophilic inorganic fillers have strong cohesiveness among fillers, and the inorganic fillers filled in polypropylene aggregate and become a source of impact stress concentration. Therefore, the surface of the inorganic filler is modified, It is desirable to disperse the impact stress uniformly in the polypropylene in multiple directions. This surface modification includes surface modification with a lipophilic surfactant treatment, surface modification with a lipophilic reactive reagent, surface grafting or coating with a polymerizable monomer or oligomer, surface coating with a resin, electrical This can be carried out by a general surface treatment method such as coating with an inorganic material having a different charge.

As a nucleating agent, one that has the effect of regulating the crystal nucleation rate of polypropylene, accelerating the crystallization rate, and at the same time suppressing the crystal size, that is, an organic nucleating agent,
Metal salts of organic acids, such as benzoic acid, cyclohexanecarboxylic acid, diphenylacetic acid, isonicotinic acid, adipic acid, sebacic acid, phthalic acid, benzenesulfonic acid, glycolic acid, etc. Metals such as magnesium, calcium, sodium, aluminum, titanium, etc. Salts; amine salts of organic acids such as benzoic acid. Amines derived from phthalic acid, adipic acid, etc. are used.

Note that fine powder of silica, alumina 6-talc, etc. is used as the inorganic nucleating agent. The combination of the above-mentioned types of inorganic nucleating agent and filler may be different as long as they are different.
If the composition is the same, the impact resistance will not be improved.

Is the amount of nucleating agent 0.05 to 0.5 by weight? When added to the filler-containing polypropylene described above, it provides the desired effect of improving impact resistance.

The polypropylene used in the present invention is a crystalline polypropylene having a melt index of 10 or less, or a propylene-ethylene block copolymer having an ethylene content of 30 to 70 by weight, preferably 3 to 30 to 70 by weight.
5 weight? ,Preferably. ．． 60-90 weight 70 is blended.

Note that other reinforcing agents such as glass fiber may be added.

Further, desired additives such as heat stabilizers, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, pigments, etc. may be blended. The above-mentioned inorganic filler and nucleating agent need to be sufficiently cross-dispersed.

Therefore, the order of filling polypropylene is to first uniformly disperse the nucleating agent into the polypropylene, then mix the inorganic filler, or to uniformly coat the surface of the inorganic filler with the nucleating agent. Filling into polymers is desirable. According to the present invention, the impact resistance of a polypropylene composition can be improved, and a material with excellent impact resistance, well-balanced physical properties, and good moldability can be provided.

Furthermore, a wide range of uses can be selected by selecting the inorganic filler and nucleating agent. In particular, industrial supplies, containers, large containers,
It is advantageous to mold it into products in the field of pipes, cardboard boxes, etc. The impact resistance improving method of the present invention will be explained below with reference to Examples, and the following test method was used. Example 1> Crystalline polypropylene 809 with a melt index of 0.3 was melted in a 6-inch roll heated to 210°C, and aluminum p-(t-butyl)benzoate, sodium benzenesulfonate, and amine talc phthalate were added as nucleating agents. ,silica,
0.259% of each alumina was added and kneaded well.

Furthermore, rutile titanium oxide with an average particle size of 0.38μ 19.7
59 was filled and kneaded thoroughly, the mixture was placed in a push mold, and an Izod test piece was molded using a 40-ton hot press. Test piece at temperature 2
After being left for 3 days at 0° C. and humidity of 5° C., an Izod impact test was conducted. Table 1 shows the results in comparison with Comparative Example 1 shown below. Comparative Example 1> Table 1 shows the results when rutile titanium oxide was not filled, when a nucleating agent was not filled, and when neither rutile titanium oxide nor nucleating agent was filled using the same method as in Example 1. This is shown in comparison with Example 1.

Example 2 The same procedure as in Example 1 was carried out except that aluminum P-(t-butyl)benzoate was used as a nucleating agent at 0.259 kg and various fillers were used at 19.759 kg.

Table 2 shows the results in comparison with Comparative Example 2 shown below. Comparative Example 2 Table 2 compares the cases in which the nucleating agent of Example 2 was not added, the case in which the filler was not added, and the cases in which both the filler and the nucleating agent were not added. and showed.

<Example 3> Crystalline polypropylene of various melt indexes or propylene-ethylene block copolymer 809, aluminum P-(t-butyl)benzoate 0.2 as a nucleating agent
5) The same procedure as in Example 1 was conducted using rutile titanium oxide 19.759 as the filler.

Table 3 shows the results in comparison with Comparative Example 3 shown below. <Comparative Example 3> The case where the nucleating agent of Example 3 was not added is shown in Table 3 in comparison with Example 3.

Example 4> Crystalline polypropylene 70 with melt index 0.3
0.25 parts by weight of aluminum P-(t-butyl)benzoate was added to each part by weight, and pelletized using a screw type extruder.

29.75 parts by weight of rutile-type titanium oxide was added to the pellets, mixed for 20 minutes in a single-type blender, and then re-pelletized using a single-screw extruder. This pellet was used to make Izod impact test pieces, falling ball impact test pieces, bending stiffness, and heat distortion temperature test pieces using a plunger type injection molding machine, and after being left at a temperature of 20°C and humidity of 60% for 3 days. Each test was conducted. Table 4 shows the results in comparison with Comparative Example 4 shown below. Comparative Example 4 Table 4 shows the results when the filler of Example 4 was not filled, when the nucleating agent was not filled, and when both the filler and nucleating agent were not filled. Shown in comparison.

<Example 5> The results of the Izod impact test when different types of inorganic fillers and nucleating agents were combined as shown in Table 5 in the same manner as in Example 1 were compared with Comparative Example 5 shown below. It is shown in Table 5.

Comparative Example 5 Table 5 shows the results when the same inorganic filler and nucleating agent as in Example 5 were used in combination, and when no filler was used in comparison with Example 5.

Claims (1)

[Claims] 1 One type of nucleating agent selected from metal salts or amine salts of non-higher fatty acid organic acids, silica, alumina, and talc0
．． Crystalline polypropylene with a melt index of 10 or less or propylene with an ethylene content of 30% or less A method for improving impact resistance, which comprises blending and kneading 30 to 95% by weight of an ethylene block copolymer.