JPS6247217B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyolefin resin composition prepared by adding a surfactant and an organic compound nucleating agent to a polyolefin resin such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc. This is a polyolefin resin composition that suppresses bleeding of surfactants. In general, polyolefin resins are hydrophobic in structure, so when molded products made from polyolefin resins are placed under high humidity, water droplets aggregate on the surface, resulting in cloudiness. In addition, since polyolefin resins generally have high electrical insulation properties, they tend to be electrostatically charged, and have the disadvantage that their commercial value decreases due to the adhesion of dust and the like. In order to compensate for the above drawbacks, various surfactants have traditionally been kneaded into polyolefin resins as antifogging agents or antistatic agents to make the surface of molded products made of polyolefin resin compositions hydrophilic. It also prevents fogging due to agglomeration of water droplets, and has an antistatic effect to prevent dust from adhering to the surface. However, although surfactants blended into polyolefin resins by kneading, etc. have excellent effects on modifying polyolefin resins, they generally have poor compatibility with polyolefin resins, and therefore, depending on the conditions. Eventually, a phenomenon called so-called bleed or blooming occurs, in which excessive exudation occurs on the surface of the polyolefin resin. In particular, when these surfactants are high melting point substances, they have the disadvantage of devitrification or impairing the appearance due to whitening, and when they are low melting point substances, they become sticky, resulting in a decrease in slip properties, printability, adhesion, etc. This results in quality deterioration such as dust adhesion. Particularly when used in packaging containers, etc., there is a problem of migration to the package contents. Furthermore, if the amount of surfactant added is reduced in order to prevent the bleed phenomenon, the effect is reduced and the intended purpose cannot be achieved in many cases. As a countermeasure to this problem, conventional methods include adding a combination of surfactants with different structures to polyolefin resin, or mixing inorganic compounds such as silica and calcium carbonate together with the surfactant to adsorb the surfactant. Methods have been taken to suppress bleeding, but in the former case, the original function of the surfactant is reduced, and in the latter case, the transparency of the polyolefin resin may be reduced, or the polyolefin resin may be used in large amounts. Since the effect cannot be seen unless it is kneaded into the mixture, there are also problems with workability. The present invention relates to a polyolefin resin composition that can address the above-mentioned problems, and utilizes the advantages of surfactants that have excellent effects on improving polyolefin resins, while also eliminating the drawbacks associated with the blending of surfactants. This is the solution. That is, it is a polyolefin resin composition containing a surfactant and an organic compound nucleating agent. Polyolefin resins related to the present invention include polyethylene, polypropylene, ethylene-
Propylene copolymer, polybutene, ethylene-
A vinyl acetate copolymer or the like may be used, and a mixture thereof may also be used. The surfactants used in the present invention include glycerin fatty acid esters, ethylene oxide adducts of glycerin fatty acid esters, sorbitan fatty acid esters, ethylene oxide adducts of sorbitan fatty acid esters, propylene glycol fatty acid esters, sucrose fatty acid esters, and citric acid mono (di) or tri) stearic acid ester, bentaerythritol fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxypropylene fatty acid ester, polyoxyethylene dodecyl ether, polyoxyethylene alkyl phenyl ether, N,N-bis(2 -hydroxyethyl) fatty acid amide, polyoxyethylene polypropylene block polymer,
Nonionic surfactants such as polyethylene glycol and polypropylene glycol are mainly used, but anionic surfactants, cationic surfactants, and amphoteric surfactants are also used depending on the purpose.
These surfactants are usually polyolefin resins.
It is used in an amount of 0.1 to 5 parts by weight per 100 parts by weight. Nucleating agents for organic compounds according to the present invention include organic acids and their derivatives, sorbitol derivatives, and polymeric compounds having a higher melting point than polyolefin resins. Examples of organic acids include benzoic acid, salicylic acid, adipic acid, and thiodiglycolic acid.
As derivatives of organic acids, sodium salts of organic acids,
Examples include metal salts such as potassium salts, magnesium salts, and aluminum salts, and amine salts of organic acids.
As a sorbitol derivative, dibenzylidene-D
-Sorbitol etc. Examples of the polymer compound include polyethylene terephthalate and polyamide. The amount of these nucleating agents is in the range of 0.001 to 1.0 parts by weight, preferably 0.005 to 0.1 parts by weight, per 100 parts by weight of the polyolefin resin. If the amount is too high, not only will the effect not be expected to increase, but on the contrary, it will be excessively dispersed in the polyolefin resin, which will cause the polyolefin resin to lose its original transparency and deteriorate the physical properties of the polyolefin resin. I'm coming too. Incidentally, inorganic compounds such as alumina, silica, and talc are known as nucleating agents, but these are ineffective compared to organic compound nucleating agents unless they are kneaded into the polyolefin resin in large quantities. Therefore, it not only has a problem with workability when kneaded into the polyolefin resin or has an adverse effect on the various physical properties of the polyolefin resin, but also has the disadvantage of impairing the inherent transparency of the polyolefin resin. Next, a surfactant or an organic compound nucleating agent is added to the polyolefin resin, but a general method of addition may be used. A nucleating agent is added at the same time as the activator, and after thorough mixing, the mixture is kneaded using an extractor, and the resulting pellets are extruded, injection molded, etc. to obtain films, sheets, and other molded products. It is also possible to prepare a high-concentration masterbatch and dilute it to the concentration required for the polyolefin resin during molding. In the present invention, by adding a nucleating agent, which is conventionally used to increase the rigidity, transparency, gloss, etc. of resin, excessive bleeding of the kneaded surfactant to the surface of molded products, etc. can be prevented. Alternatively, blooming is significantly suppressed, and it has a high degree of sustainability, and it also increases the rigidity, transparency, gloss, etc. of the polyolefin resin, which is the original purpose of the nucleating agent. Next, examples will be shown. Example 1 100 parts by weight of ethylene-propylene copolymer (Mitsubishi Noblen FW-3 manufactured by Mitsubishi Yuka) 2 parts by weight of glycerin fatty acid ester The following nucleating agents were added to the above composition in an amount of 0.002 parts,
After adding 0.01 and 0.05 parts by weight and mixing well with a Benciel mixer, the pellets obtained by kneading with an extractor were inflation molded at 200°C to obtain a 40 μm film. The anti-fogging property and surface bleed state of the above films were compared immediately after molding and after being left for 1 week, 2 weeks, and 4 weeks in an environment of 25° C. and 60% relative humidity. Nucleating agent 1 Benzoic acid aluminum salt 2 Dibenzylidene-D-sorbitol 3 Polyethylene terephthalate (melting point 265°C)

[Table] Example 2 0.05 parts by weight of benzoic acid aluminum salt as a nucleating agent was added to the same polyolefin resin as in Example 1, and the same experiment as in Example 1 was carried out using the following several types of surfactants. Comparison was made with one without the addition of nucleating agent. Surfactant 1 Glycerin fatty acid ester 2 Pentaerythritol fatty acid ester 3 Sorbitan fatty acid ester 4 Propylene oxide nonyl phenyl ether 5 Propylene oxide fatty acid ester

[Table] Example 3 High-density polyethylene (Hizex manufactured by Mitsui Petrochemicals)
2100J) 100 parts by weight Pentaerythritol fatty acid ester 2 parts by weight 1. 0.005 parts by weight, 2. 0.01 parts by weight, and 3. 0.05 parts by weight of benzoic acid aluminum salt as a nucleating agent were added to the above composition, and Example 1 and Molded products obtained by injection molding pellets obtained in a similar manner at 220°C were heated at 25°C and 60% relative humidity immediately after molding.
Changes in surface resistance and surface bleed state after being left for one week, two weeks, and four weeks were compared. In addition, experimental results are also shown for cases in which only high-density polyethylene and only high-density polyethylene and pentaerythritol fatty acid ester were used without containing a nucleating agent.

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Claims (1)

[Claims] 1. Based on 100 parts by weight of polyolefin resin,
A polyolefin resin composition containing 0.1 to 5 parts by weight of a surfactant and 0.001 to 1.0 parts by weight of an organic compound nucleating agent, and substantially free of barium sulfate having an average particle size of 3 μm or less. 2. The polyolefin resin composition according to claim 1, wherein the surfactant is a nonionic surfactant.