JPS6119645A - Heat-resistant, transparent polyolefin resin composition - Google Patents

Abstract

PURPOSE:The titled resin composition which has high heat resistance, gives a transparent molded article suffering neither blooming nor bleeding, and is made by incorporating a specified phenolic antioxidant and a specified thioic antioxidant into a polyethylene resin. CONSTITUTION:At least 2pts.wt. mixture of N,N'-hexamethylenebis(3,5-di-tert- butyl-4-hydrocinnamamide) (a phenolic antioxidant) and distearyl thiodipropionate (a thioic antioxidant) in a weight ratio of 1:1-6:1 is incorporated into 100pts.wt. polyethylene resin (e.g. polyethylene or an ethylene-vinyl acetate copolymer) to give the titled resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a heat-resistant transparent polyolenoin resin composition that has heat resistance and can yield transparent molded articles.

[Prior art] Recently, electric wires and wires used for electronic J3 and electrical equipment have been
In the case of gooples and dupes used for covering end treatments, materials that have not only good physical properties but also high heat resistance and transparency are required.

Polyethylene resins and copolymer resins mainly composed of ethylene have good transparency by themselves, but bloom and bleed occur when large amounts of antioxidants are added to give them heat resistance. However, there is a problem in that transparency may be impaired depending on the object.

[Problem to be Solved by the Invention 1] The present invention has been made based on the above, and provides a heat-resistant transparent polyolefin that has a high degree of heat resistance and can produce transparent molded products without bloom or bleed. The purpose is to provide a resin composition.

[Means for Solving the Problems] The resin composition of the present invention includes a polyethylene resin or a copolymer resin mainly composed of ethylene, and N, N', which are phenolic antioxidants that do not impair the transparency of these resins. -hexyl-methylenebis(3,5-di-tert-butyl-4-
Human [1synnormamide] and the thio-based antioxidant disde>7lyldiodibrobionate are used together in a weight ratio of 1:1 to 6:1, and these antioxidant 11- The total amount of the agent is 2 parts by weight or more based on 100 parts by weight of the resin.

In the present invention, polyethylene resins include low, medium,
Any high density polyethylene may be used.

As a copolymer resin mainly composed of ethylene, ethylene-
Examples thereof include propylene copolymer, dilefoubdene copolymer, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer.

These resins can be used alone or in combination of two or more.

In the present invention, the phenolic antioxidant IV agent N
It is important to use N'-hexamethylenebis(3,5-di-tert-butyl-4-hydrocinnamamide) in combination with disderyl thiodipropionate, which is a thio-based antioxidant. It has been discovered that the synergistic effect of both can provide a heat resistance of 250° C. for 4 hours, and also provide a molded product without bloom or bleed.

Furthermore, none of these antioxidants impairs the transparency of the resin.

The combination ratio of fuconol-based antioxidants and thio-based antioxidants must be in the range of 1:1 or 66:1, and if the amount of thio-based antioxidants exceeds 1:1, bloom will occur. If the amount of thio-based antioxidant is less than 6:1, a synergistic effect cannot be obtained.

In addition, these antioxidants are added at 2 parts by weight per 100 parts by weight of the resin.
It is necessary to add at least 1 part of the weight, and if it is less than this, the desired high degree of heat resistance cannot be imparted.

Although the molded article obtained from the resin composition of the present invention can be used in an uncrosslinked state, crosslinking can improve heat deformation resistance and chemical resistance.

Crosslinking methods include heating crosslinking and ionizing radiation irradiation.
Examples include 3-crosslinking.

When performing irradiation crosslinking, 0.5 to 10 parts by weight of polyfunctional nanatsuma is added in order to enable crosslinking with low radiation m and to prevent deterioration of the resin and antioxidant 1 agent due to ionizing radiation. Generally, it is added within the range of .

Examples of polyfunctional methacrylates include acrylates (di-1-dimethyl glycol diacrylate, etc.), dimethacrylates (
Trimethacrylates (trimethylolethane triacrylate, trimethyl ethane triacrylate, etc.), trimethacrylates (trimethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, dipropylene glycol dimethacrylate, etc.) Trimethacrylate.

Trimethylolp [pantrimethacrylate, etc.),
Examples include triallyl cyanurate, triallyl isocyanurate, diallyl maleate, and the like.

In the present invention, fillers 2, colorants, lubricants, etc. that do not impair transparency may be added in addition to the above-mentioned components.

[Example] A covering resin composition containing various components was prepared with the mixing ratios shown on each side of Table 1, and this was press-molded into a sheet.

For Examples 4 to 7 and Comparative Examples 4 to 6, a 10 Mrad electron beam was irradiated with a 1.5 Mev electron beam accelerator to form a sheet, and the evaluation results for each side were as shown in the lower column of Table 1. be.

The evaluation was based on the following.

Heat resistance test: For uncrosslinked sheets, a sheet with a thickness of 1 am is placed on top of a Teflon sheet, heated at 250°C for 4 hours, then bent at room temperature and judged by the presence or absence of cracks.For crosslinked sheets, the thickness 1 mm sheet at 250℃
After heating it for 4 hours, it was bent at room temperature and judged by the presence or absence of cracks.

Bloom and bleed test: A sheet with a thickness of 1# is left at room temperature, and the surface condition is visually judged with the naked eye (for those irradiated with an electron beam, the judgment is made after irradiation).

Transparency: Judging by visual inspection of a 0.5# thick sheet with the naked eye.

[Effects of the Invention] As explained above, by using the resin composition of the present invention, it is possible to produce a polyolefin resin molded article that has excellent transparency and heat resistance, and is free from bloom and bleed. It becomes possible.

Claims (1)

[Claims] (1) N,N'-hexamethylene bis(N,N'-hexamethylene bis(
3,5-di-tert-butyl-4-hydrocinnamamide) and distearyl thiodipropionate, a thio-based antioxidant, in a weight ratio of 1:1 to 6:1. A heat-resistant transparent polyolefin resin composition characterized in that when used in combination, the total amount of these antioxidants is 2 parts by weight or more based on 100 parts by weight of the resin content.