JPH0464552B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to an internally kneaded antistatic agent composition for plastics. Prior Art Plastics generally have high electrical insulation properties, and are prone to generating and accumulating static electricity due to friction. If such electrification occurs, for example, it may become difficult to peel off the thin plastic film, reducing the efficiency of the manufacturing and packaging process, and in extreme cases, there is even a risk of accidents due to spark discharge. In addition, it absorbs dirt such as dust from plastic products, impairing its appearance and impeding printing and painting. As a method to prevent this phenomenon, antistatic surfactants are used.
There are two methods for this: one is to apply the surfactant to the surface, and the other is to knead it into the interior. In particular, the method using an internally kneaded antistatic agent is superior in that it can be kneaded into the molding resin in advance to form master pellets and in that the antistatic effect is sustainable. Internally kneaded antistatic agents are effective by bleeding onto the surface of the resin after molding and forming a conductive layer, so they are fast-acting and exhibit their antistatic effect quickly. Both the effect and the sustainability are required. Conventionally, various surfactants such as amine compounds, fatty acid polyhydric alcohol esters, polyoxyethylene alkyl ethers, and alkylaryl sulfonates have been proposed as internally kneaded antistatic agents. However, no antistatic agent has yet been found that is physiologically safe, exhibits antistatic effects quickly, and has a long-lasting effect. For example, glycerin monofatty acid esters have long been used in food emulsifiers and the like, and are known to be highly safe. Regarding the antistatic properties of glycerin monofatty acid esters in polyolefin resins, as reported in Karimae, Yushi 31. No. 5.77 (1978), glycerin monodecanoate esters having an alkyl group having 10 carbon atoms are the best; It is known that the antistatic effect decreases as the chain length of the alkyl group becomes shorter or longer than 10 carbon atoms. However, short chain length glycerin monofatty acid esters such as glycerin monodecanoate esters are highly volatile when kneaded into resins, so they cannot be put to practical use. On the other hand, the number of carbon
Glycerin monofatty acid esters with long chain lengths 16 and 18 have insufficient antistatic effect, and
It has been reported that the antistatic effect decreases over time and there are problems with sustainability (Japanese Patent Application Laid-Open No. 1973-
Publication No. 92853). Therefore, for example,
As shown in Publication No. 925, a method has been proposed to improve the antistatic effect by using an amino compound in combination with a surfactant, but the onset of the effect is slow and the antistatic property is not sufficiently satisfactory. It wasn't a kimono. Further, JP-A No. 59-12957 reports that antistatic properties are imparted to methacrylic resin by using high purity glycerin monolaurate and alkanol or glycerin. however,
This method is still unsatisfactory, as it is a general-purpose plastic and cannot provide a sufficient antistatic effect for polyolefin resins. Purpose of the Invention The present invention provides a rapid onset of antistatic effect, and
The object of the present invention is to provide an internally kneaded antistatic agent composition for plastics that has long-lasting properties. Structure of the Invention The antistatic composition for plastics of the present invention comprises the following components (A) and (B) in a weight ratio of (A)/(B)=3/
It is characterized by containing in the range of 7 to 8/2. (A) The following (A-1) component and (A-2) component in a weight ratio of (A-1):(A-2) = 90:10 ~
Mixed glycerin monofatty acid ester (A-1) containing glycerin monostearate (A-2) glycerin monopalmitate (B) containing the following components (B-1) and (B-2) in a ratio of 20:80 by weight Ratio (B-1):(B-2)=90:10~
Mixed higher alcohol (B-1) Stearyl alcohol (B-2) Cetyl alcohol contained in a ratio of 10:90 The present invention will be explained in more detail below. The blending ratio of the mixed glycerin monofatty acid ester of component (A) is glycerin monostearate:glycerin monopalmitate = 90:10-20:
It is necessary to set the ratio to 80:20, preferably 80:20~
The range is 30:70. If the blending ratio deviates from the above range, sufficient antistatic ability will not be obtained. (A) Mixed glycerin monofatty acid ester is, for example, glycerin monostearate obtained by an esterification reaction of glycerin and stearic acid, and glycerin monopalminate obtained by an esterification reaction of glycerin and palmitic acid. It can be obtained by blending with tate in a predetermined ratio. It can also be obtained by an esterification reaction of a mixed fatty acid of stearic acid and palmitic acid, or a fatty acid derived from oil such as natural beef tallow or soybean oil with glycerin. When using fatty acids derived from natural fats and oils, it is appropriate to adjust the fatty acids so that they contain 90% by weight or more of saturated fatty acids having 18 and 16 carbon atoms. Further, the mixed glycerin monofatty acid ester of the present invention can also be obtained by the above-mentioned transesterification reaction between oil and fat and glycerin. The mixed glycerin monofatty acid ester of component (A) may contain byproducts glycerin difatty acid ester and glycerin trifatty acid ester, but the content of these impurities must be 10% by weight or less. is desirable. The lack of sustainability of the antistatic effect of glycerin monofatty acid ester is thought to be due to changes in the association structure of the conductive layer formed on the resin surface. It is effective to combine a higher alcohol having a carbon skeleton similar to the alkyl chain of the fatty acid residue of the glycerin monofatty acid ester. Therefore,
In the present invention, C ₁₆ and C ₁₈ saturated alcohols having the same number of carbon atoms are used in combination with the above mixed fatty acid ester. It is thought that these glycerin monofatty acid esters and higher alcohols form a mixed crystal, contributing to the sustainability of the antistatic effect. The blending ratio of the mixed higher alcohol of component (B) is stearyl alcohol: cetyl alcohol = 90:10 to 10:90, preferably 90:10 to
It is 20:80. If this blending ratio deviates from the above range, sufficient antistatic ability will not be obtained. This mixed higher alcohol can be obtained, for example, by blending stearyl alcohol and cetyl alcohol in a predetermined ratio, and can also be derived from natural fats and oils such as beef tallow and soybean oil. In the latter case, it is appropriate to adjust the content of saturated higher alcohols having 16 and 18 carbon atoms to 90% by weight or more. The antistatic agent composition of the present invention comprises (A) component mixed glycerin monofatty acid ester and (B) component mixed higher alcohol in a weight ratio of (A) component/(B) component = 3/
Contained in the range of 7 to 8/2. If the proportion of (A) mixed glycerin fatty acid ester is less than this, the antistatic effect will be reduced, and if it is too much, the antistatic effect will not last long enough. The amount of the antistatic agent composition of the present invention added is suitably 0.05 to 5 parts by weight per 100 parts by weight of plastic. If the amount added is less than 0.05 parts by weight, a satisfactory antistatic effect will not be exhibited, while if it exceeds 5 parts by weight, bleed-out will increase more than necessary, resulting in stickiness on the product surface, which is undesirable. . The amount added is more preferably 0.1 to 2 parts by weight than in the composition of the present invention. The antistatic agent composition of the present invention is effective when kneaded into plastics, and is particularly suitable for polyolefin resins. Polyolefin resins include polyethylene, polypropylene, poly-1-butene, poly-1-pentene, poly-1
- Polymers such as hexane and poly-1-octene,
Alternatively, copolymers of monomers having these structures, mixtures of these polymers, etc. may be used. The antistatic agent composition of the present invention may be kneaded when molding plastic, or components (A) and (B) may be added separately and kneaded. Alternatively, the antistatic agent composition may be kneaded in advance at a high concentration to form master pellets, which may be diluted and molded. Additives such as stabilizers, colorants, fillers, lubricants, UV absorbers, etc. can also be added to the plastics. The resin containing the antistatic agent composition of the present invention is
It can be molded into sheets, films, and various other shapes by conventional molding methods such as press processing, injection molding, blow molding, extrusion molding, powder molding, and calendar molding. Effects of the Invention The antistatic agent composition for plastics of the present invention has the following properties:
By kneading it into plastic, the antistatic effect can be quickly exerted and the effect can be sustained over a long period of time. Example An antistatic agent composition having the composition shown in Table 1 is added to 100 parts by weight of a polypropylene resin having a melt index of 5.0 (manufactured by Mitsubishi Yuka Co., Ltd., Mitsubishi Noblen MA-4).
0.4 part by weight was added and kneaded using an extruder to prepare strand pellets. Next, this pellet is molded into a cylinder at a temperature of 230°C using an injection molding machine.
The sample was molded into a plate-like sample measuring 76 mm x 76 mm x 1.6 mm, and used to measure the antistatic effect. The antistatic effect was determined by holding the sample at a constant temperature of 20° C. and 65% humidity for a predetermined period of time, and then measuring the half-life of the charging voltage and stain resistance. The measurement results of the antistatic effect are shown in Table 1. The half-life of the charged voltage was measured using a statistical honesty meter (manufactured by Shishi Shokai), and the contamination resistance was determined by placing the sample in a dirt chamber and visually determining the degree of contamination by carbon at that time. ○: No contamination △: Contamination ×: Considerable contamination

【table】

[Table] *1: Glycerin monohardened beef tallow fatty acid ester *2: Hardened beef tallow alcohol *3: Yoneyama Pharmaceutical Co., Ltd. reagent stearyl alcohol

Claims (1)

[Claims] 1 (A) Glycerin monostearate and glycerin monopalmitate in a weight ratio of 90:10 to 20:
Mixed glycerin monofatty acid ester containing in the range of 80 and (B) mixed higher alcohol containing stearyl alcohol and cetyl alcohol in the range of 90:10 to 10:90 in weight ratio, (A) / (B) = An antistatic agent composition for plastics, characterized in that the composition contains an antistatic agent in the range of 3/7 to 8/2.