JPS6244779B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ethylene resin composition having excellent antistatic properties.

Polyethylene is widely used as a raw material for films, pipes, fibers, and other molded products due to its excellent chemical and physical properties, but like many other plastics, it has high electrical insulation resistance and is therefore susceptible to friction, etc. more likely to be charged with static electricity,
It causes various troubles and disasters, and also has the disadvantage that the surface of the molded product becomes dirty due to the adhesion of dust. Therefore, it is extremely important in practice to prevent polyethylene from being charged.

Antistatic agents such as polyethylene are required to have properties such as compatibility with resins and processing stability in addition to antistatic properties. Further, it is not preferable that the antistatic agent excessively precipitates (bleeds) on the surface, causing stickiness, whitening, etc., and significantly deteriorating the appearance and physical properties of the surface of the molded product. However, an antistatic agent that satisfies all these requirements has not yet been found.

The present inventors have conducted extensive research to obtain a polyethylene resin composition with excellent antistatic properties in these respects, and as a result, the inventors have found that a specific tertiary amine and an oxidized polyethylene wax can be used in combination. It has been found that this method improves the stickiness and synergistically improves the antistatic effect.

The present invention is based on the general formula (In the formula, R represents an alkyl group or alkenyl group having 12 to 22 carbon atoms) and an alkyl- or alkenyldihydroxyethylamine having a molecular weight of 1000
This is an electrically-proof resin composition characterized by containing an oxidized polyethylene wax having an acid value of 5 to 9000 and an ethylene polymer of 5 to 70.

R of the amine in the formula has 12 to 22 carbon atoms;
Alkyl or alkenyl groups are suitable. Those with a carbon number of 11 or less have a low boiling point and may evaporate when heated and kneaded with a resin. Also, the number of carbon
Polymers of 23 or more are not preferred because their industrial availability is restricted from the viewpoint of raw materials.

Oxidized polyethylene wax has a molecular weight of 1000~
9000, and those with an acid value of 5 to 70 are used. molecular weight
If the molecular weight is less than 1,000, it has a low melting point, poor heat resistance, and tends to precipitate (bleed) on the resin surface.If the molecular weight exceeds 9,000, the melting point is too high, resulting in poor processability. Further, if the acid value is less than 5, a sufficient synergistic effect cannot be obtained, and if it exceeds 70, thermal stability deteriorates.

As the ethylene polymer, polyethylene and ethylene copolymers are used. Mixtures of these polymers can of course also be used.

Any of low density, medium density and high density polyethylene can be used. As the ethylene copolymer, a copolymer containing 60% or more of ethylene, such as an ethylene/vinyl acetate copolymer, an ethylene/acrylic acid ester copolymer, etc., is used.

When producing the electrically conductive resin composition of the present invention, an amine of the formula and an oxidized polyethylene wax are added to polyethylene or an ethylene copolymer. The amount of amine added is 0.05 to 0.05 to the resin composition.
2% by weight, and 0.05-5% by weight of oxidized polyethylene wax is preferred. The blending ratio of these components can be changed as appropriate depending on the required antistatic properties and surface condition of the final molded product.

Next, this mixture is uniformly kneaded using a kneading device such as a roller mill, Banbury mixer, or extruder to obtain the composition of the present invention.

In addition, the composition of the present invention may also contain antioxidants, light stabilizers, lubricants, pigments, and other additives.

Films and other molded products obtained from the resin composition of the present invention have improved stickiness and excellent electrical resistance.

In the examples below, % means weight.

Example 1 0.15% of tetradecyl-dihydroxyethylamine and 0.15% of oxidized polyethylene wax (molecular weight 2000, acid value 10) were added to commercially available polyethylene (trade name: Asahi Dow Polyethylene F1920), mixed in a V-shaped tumbler, and then extruded. The mixture was granulated into pellets using a machine, and a film (A) was produced using the pellets by an inflation method.

For comparison, use the same method, but with tetradecyl-
A film with only 0.15% dihydroxyethylamine added to polyethylene (B) and a film made only of polyethylene without additives (C) were produced. The surface resistivity and stickiness of these films were examined using the following methods.

The surface resistivity was measured using a super megohmmeter SM-5E manufactured by Toa Denpa Kogyo. After molding the sample, it was conditioned for 7 days under standard conditions of a temperature of 20°C and a relative humidity of 65%, and measurements were conducted under the same conditions.

For stickiness, measure two samples with a width of 3 cm and a length of 4 cm.
After placing a 500g weight on top of this and adjusting it for 24 hours in an atmosphere with a temperature of 20℃ and a relative humidity of 65%, the two samples were peeled off by hand and graded according to the ease of peeling: large, medium, The evaluation was divided into three levels: small.

The test results are shown in Table 1. Note that antioxidants are added to commercially available polyethylene. According to this result, it is recognized that A has an excellent surface resistivity.

Table 1 Sample Surface specific resistance Stickiness A 3 x 10 ¹⁰ Ω Medium B 2 x 10 ¹¹ Ω Large C > 10 ¹⁴ Ω Small Example 2 To the polyethylene used in Example 1, 0.3% octadecyl-dihydroxyethylamine and polyethylene oxide were added. Wax (molecular weight 2000, acid value 10) 0.3
% was added, and a film (D) was produced in the same manner as in Example 1.

Also, octadecyl-dihydroxyethylamine
Film (E) with only 0.3% added and oxidized polyethylene wax (molecular weight 2000, acid value 10)
A film (F) containing only 0.3% was produced. Using these films and additive-free film (C),
The same test as in Example 1 was conducted. The results are shown in Table 2. In sample D, a clear synergistic effect was observed.

Table 2 Sample Surface specific resistance Stickiness D 5 x 10 ¹⁰ Ω Medium E 9 x 10 ¹¹ Ω Large F > 10 ¹⁴ Ω Small C > 10 ¹⁴ Ω Small Example 3 Tetradecyl-dihydroxy was added to the polyethylene used in Example 1. Ethylamine 0.3% and oxidized polyethylene wax (molecular weight 2000, acid value 10) 1.5
% added film (G), as well as 0.3% tetradecyl-dihydroxyethylamine and oxidized polyethylene wax (molecular weight 5000, oxidation 30) 0.3%
A film (H) to which was added was produced in the same manner as in Example 1. Further, a film (I) containing only 0.3% of tetradecyl-dihydroxyethylamine was produced and the same test as in Example 1 was conducted. The results are shown in Table 3. In addition, film (C) was also used for comparison. A clear synergistic effect was observed in samples G and H.

Table 3 Sample Surface specific resistance Surface resistance G 2×10 ⁹ Ω Medium H 8×10 ⁸ Ω Medium I 7×10 ¹⁰ Ω Large C ＞10 ¹⁴ Ω Small

Claims (1)

[Claims] 1. General formula (In the formula, R represents an alkyl group or alkenyl group having 12 to 22 carbon atoms) and an alkyl- or alkenyldihydroxyethylamine having a molecular weight of 1000
9,000 and an acid value of 5 to 70 in an ethylene polymer.