JPS6079950A - Radiation-resistant film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to radiation-resistant films.

Conventionally, biaxially oriented polypropylene film (hereinafter abbreviated as OFF film) has been widely used as a variety of packaging materials because it has strength, stay-7ness, impact resistance, etc., good transparency, and excellent moisture resistance. It is being However, among various packages, this common bacteria is sterilized by injection in the evening, but these packages do not contain O.
When using a PP film, 5, op
P-film could not be used as a packaging material for radiation sterilization because it was significantly decomposed and deteriorated and its mechanical strength decreased.

Therefore, we considered making the OPP film radiation resistant, but in order to make it radiation resistant, various problems may occur during film formation due to the large amount of additives added to the resin. Resin loss due to quality deterioration due to plateout of the agent)! There are problems in that processing, film forming process control, film lot control, etc. are complicated, resulting in poor workability and high manufacturing costs.

The present invention was made for the purpose of solving the above-mentioned problems regarding radiation-resistant OPP films, and includes (a) a hindered amine compound and (an organophosphorus compound and/or (0) The present invention provides a radiation-resistant film formed by laminating a hindered phenol compound and a stretched polypropylene film.

The hindered amine compound used in the present invention preferably has a low molecular weight of 500 or less, such as bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, Gutudrite-5054 (trade name,
TMN 20 (Manufactured by Gutdrich Chemical Co., Ltd.), Hex)
(Product name, manufactured by Hoechst), UV-545y (Product name,
manufactured by American Cyanamite), Tetrakis (2,2
,6,6-tetramethyl-4-piperidyl)-'1,2
, 5,4-butane tetracarboxylate and the like. High molecular weight hindered amine compounds are not preferred because they make it difficult to transfer from the polyolefin layer to the OPP film, which will be described later.

The organic phosphorus compounds used in the present invention include organic phosphites, such as 1,1.5-)lis(2-methyl-
4-ditridecylphosphite-5-t-butyl)butane, 4,4-butylidene-bis(5-methyl-6-t-
butylphenyl-ditridecyl) phosphite, tris(2,4-di-t-butylphenyl) phosphite, or an organic phosphonite such as tetrakis(2°4-di-t-butylphenyl)4,4-biphenylene diphosphonite etc. can be mentioned.

Examples of the hindered phenol compounds used in the present invention include 1,3,5-to-17s(5-hydroxy-2,6-dimethyl-4-t-butylbenzyl)isocyanurate, 1,3,5,- ) dimethyl-2,4,6
-Tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 2,6-di-t-butyl-p-cresol, 4,4-thiobis-(6-t-butyl-m-cresol) , Tetrakis[methylene-5-(5,5-di-t-butyl-4-hydroxyphenyl)-propionate comethane, Stearyl-β-(3,5-di-butyl-4-hydroxyphenyl)gropionate, 1. 1.
Examples include 5-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane and tris(3,5-di-t-butyl-4-hydroxybenzyl)in cyanurate. In addition, if necessary, thioesters such as distearylthiodiglopionate, dilaurylthiodiglopionate, tetrakis-(methylene-3
-dodecylthioglobionate) methane, simiristylthiodipropionate, etc. may be added.

Examples of the polyolefin used in the present invention include high density, medium density and low density polyethylene, linear low density polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer, etc. Polymers such as ethylene-propylene rubber, ethylene-butene rubber, etc., or mixtures thereof may be used.

A polyolefin layer containing a hindered amine compound, an organic phosphorus compound, and/or a hindered phenol compound is prepared by adding a radiation resistance imparting agent such as the hindered amine compound or compound to the polyolefin and mixing the mixture uniformly. It is a film or sheet-like product made of

Further, the method of mixing the radiation resistance imparting agent is not particularly limited, and any known method can be applied. For example, there is a method in which a radiation resistance imparting agent is added to a polyolefin powder or pellet, premixed, and then melt-kneaded at a temperature equal to or higher than the melting point of the polyolefin to form a film or sheet.

In this case, the amount of the hindered amine compound, organic phosphorus compound, and hindered phenol compound added is α1 to 1% by weight, and particularly preferably 0.2 to 0.5% by weight.
It is 5 times i%. If the amount added is less than (11% by weight), OF
F When laminated and integrated with the film, there is little migration of the radiation resistance imparting agent from the polyolefin layer to the OPP film,
The radiation resistance and kneading properties of the OPP film are not improved. on the other hand,
If the amount added exceeds 1.0% by weight, the film will be colored, and the radiation resistance imparting agent will migrate too much, resulting in rate-out between the polyolefin layer and the OFF film, resulting in blocking in the film. Undesirable.

In addition, when adding the radiation resistance imparting agent, a neutralizing agent, a lubricant, an antistatic agent, an antiblocking agent, a nucleating agent, etc. can be added as necessary.

The OFF film used in the present invention is typically thick, but is limited to the extent that a biaxial stretching effect can be achieved, or is made of a copolymer of dipropylene and a small amount of other olefins. There may be.

Next, a polyolefin layer containing a radiation resistance imparting agent and an OP
As a method for laminating and integrating with p film, for example, O
A method of dry laminating a polyolefin film or sheet-like material containing a radiation resistance imparting agent and an OPP film onto the FF film using an adhesive such as a urethane-based or titanate-based adhesive can be used.

Moreover, lamination can be performed in any combination. The thickness of the laminated film is generally preferably 5 to 50 microns.

The obtained laminated film was heated at a temperature of 50°C or higher in an atmosphere of about 40% in order to promote the transfer of the radiation resistance imparting agent contained in the polyolefin layer to the OPP film.
It is preferable to ripen for more than an hour.

As described above, in the radiation resistant film of the present invention, the radiation resistance of the OFF film is improved by the transfer of the radiation resistance imparting agent contained in the polyolefin layer to the OPP film.

Therefore, it does not deteriorate even when used as a packaging material for radiation sterilization, and is suitable as a packaging material that has the characteristics of an OPP film. In addition, since the OPP film is generally commercially available, the production cost is low.

Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, in the examples, ``chi'' indicates weight, and the evaluation method of film physical properties is as follows.

Falling ball impact strength: A height of 1090 mm is placed on a film surface held by a crumbling ring with a diameter of 127 m. A ball weighing 175 tons was dropped from the ball, the time it took for the ball to fall 500 m from the film surface was measured, and from this the energy required for membrane rupture (falling ball impact strength) was calculated.

Example Crystalline propylene-ethylene copolymer (ethylene content = 5%, melt 70-index = 50 f7
10 minutes), add a hindered amine compound, an organic phosphorus compound, and a hindered phenol compound in the proportions shown in Table 1, and further add aOSqb's distearyl thiodipropionate and aosl's calcium stearate, respectively. After preliminary mixing, the mixture was melt-kneaded to obtain a composition. This composition was extrusion coated onto an OPP film to obtain a laminated film. This laminated film was aged for 24 hours in an atmosphere with a temperature of 50°C and a humidity of 40°C. This laminated film was exposed to r
After irradiation with @, the physical properties were measured and the results are shown in Table 1.

Additive AI = bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate A: Tetrakis(2,2,6,6-tetramethyl-4
-piperidyl) -1,2,5,4-butanetetracarboxylate A3: Hekis) TMN 20 (trade name, manufactured by Hoechst) B1: 1,1j-tris(2-methyl-4-ditridecylphosphite) -5-tert-butyl)butane B! Nidris(2,4-di-t-butylphenyl)phosphite Ol: 1,5.5-tris-(5-hydroxy-2
,6-dimethyl-4-t-butylbenzyl)in cyanurate 0,: 1,5.5-)dimethyl-2,4,6-tris(5゜5-di-t-butyl-4-hydroxybenzyl)benzene Agents 1) Akira’s agent Ryo Hagiwara −

Claims (1)

[Claims] A polyolefin layer containing 0.1 to 1% by weight of (a) a hindered amine compound, (b) an organic phosphorus compound, and/or (C) a hindered phenol compound, respectively, and a biaxially oriented polyglopyrene film are laminated. Radiation resistant film.