JPS6116939A - Heat-resistant and transparent polyolefin resin composition - Google Patents

Abstract

PURPOSE:The titled composition capable of providing a transparent molded article having high heat resistance free from bloom and bleeding, obtained by blending polyethylene resin with a specific phenolic antioxidant and thio antioxidant. CONSTITUTION:(A) 100pts.wt. polyethylene resin or copolymer resin consisting essentially of ethylene is blended with (B) tetrakis-[methylene-3-(3',5'-di-tertiary- butyl-4'-hydroxyphenyl)propionate]methane as a phenolic antioxidant and a tetrakis-[methylene-(dodecy)thiopropionate]methane as a thio antioxidant in a weight ratio of the former to the latter of 1:1-6:1 in an amount to give >=2pts. wt. total amount, to give a composition having 250 deg.C-4hr heat resistance. Heat distortion properties and chemical resistance can be further improved by crosslinking.

Description

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

[Prior Art] Recently, electric wires and cables used for electronic and electrical equipment, and tubes used for covering terminals, have not only good physical properties but also a high degree of heat resistance. However, there is a growing demand for materials that have transparency v1.

Polyethylene resin and ethylene-based copolymer resins themselves have good transparency, but they are heat resistant (?
If a large amount of antioxidant is added to absorb I, bloom or bleed will occur, and there is a problem in that the transparency will be impaired if the product is contaminated.

[Problems to be Solved by the Invention] 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 2R 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, propionate comethane, and a thio-based thickening inhibitor, Tel-Lakis [ It is important to use methylene-(dodecyl)thiopropionate] methane in combination, and the synergistic effect of both allows for
It has been found that it is possible to obtain a molded product that has long heat resistance and is free from blue and bleed.

Moreover, these antioxidant 11 agents do not impair the transparency of the resin.

The combination ratio of the phenolic antioxidant IL agent and the thio-based antioxidant needs to be in the range of 1:1 to 6:1, and if the thio-based antioxidant becomes more than 1:1, Bloom and bleed occurs, and the A-based antioxidant II-
If the amount of the agent is reduced, synergistic effects cannot be obtained.

Further, it is necessary to add 1 part or more of these antioxidants to 100 parts by weight of the resin, and if the amount is less than this, the desired high heat resistance cannot be imparted.

The molded article made from the resin composition of the present invention can be used in an uncrosslinked state, but by crosslinking, heat deformation resistance and chemical resistance can be improved.

Examples of crosslinking methods include heating crosslinking and ionizing radiation crosslinking.

When performing irradiation crosslinking, in order to enable crosslinking with low irradiation wire drawing and to prevent deterioration of the resin and antioxidant due to ionizing radiation, the polyfunctional surface is Generally, it is added in an amount of 1.5 parts.

Examples of polyfunctional monomers include acrylate-1~ (diethylene glycol cyacrylate 1 note, etc.), dimethacrylate-1
(diethylene glycol dimethacrylate, dipropylene glycol dimethacrylate 1~, etc.), triacrylates (1~rimebrolethane 1~reacrylate 1~, trimedylolpropane triacrylate 1~, etc.), Methacrylates (trimethylolethane trimethacrylate.

Examples include 1-helimedium [1-propane 1-remethacrylate, etc.], 1-realyl cyanurate, triallyl isocyanurate, diallyl maleate, and the like. In the present invention, in addition to the above-mentioned components, 4T filler 9, a coloring agent, a lubricant, etc. may be added without impairing transparency.

[Example] Resin compositions containing various components were prepared at the mixing ratios shown in Table 1, and the resin compositions were press-molded into sheets.

For Examples 4 to 7 and Comparative Examples 1 to 6, a 10 Mrad electron beam was irradiated with a 1.5 Mev electron beam accelerator after molding.

The evaluation results for each item are shown in the lower column of Table 1.

The evaluation was based on the following.

Heat resistance test: For uncrosslinked seams 1~, thickness 1 mm
Place the sheet on a Teflon sheet and heat it at 250℃ for 4 hours, then bend it at room temperature and judge by the presence or absence of cracks. After heating for a period of time, bend it at room temperature and judge by the presence or absence of cracks.

Bloom and Blee 1 - Test: A sheet with a thickness of 1 mm was left at room temperature, and the surface condition was visually judged with the naked eye (for those irradiated with electron beams, the judgment was made after irradiation).

Transparency: Judging by visual inspection of a 0.5 mm 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 obtain a polyolefin resin molded article that has transparency and heat resistance of 250°C for 4 hours, and is free from bloom and bleed. becomes possible.

Claims (1)

[Claims] (1) Tetrakis-[methylene-3-(
3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane and the thio-based antioxidant, tetrakis-[methylene-(dodecyl)thiopropionate]methane, by weight of the former and latter. These antioxidants are used in combination at a ratio of 1:1 to 6:1, and the total amount of these antioxidants is 1:1 to 6:1.
A heat-resistant transparent polyolefin resin composition characterized in that the amount is 2 parts by weight or more per 00 parts by weight.