JPH0129378B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyolefin composition with excellent radiation resistance. Conventionally, polyolefins such as polypropylene and poly4-methyl-1-pentene have been widely used in medical instruments such as syringes, forceps, clamps, pipettes, containers, and food packaging materials such as films and packs. By the way, when used in the medical and food fields, boiling or gas sterilization is usually performed. However, boiling sterilization may not completely sterilize, and gas sterilization may leave toxic gases in the container or syringe cylinder, so sterilization using radioactivity (gamma rays) is attracting attention in the future. . However, when polyolefin is irradiated with radiation, the resin decomposes and deteriorates, resulting in a decrease in mechanical strength, and discoloration occurs due to the decomposition of various compounding agents contained in the resin, reducing product value. You can see the phenomenon. Therefore, the inventor of the present invention has conducted intensive studies on the formulation of compounding agents to prevent a decrease in mechanical strength and prevent product coloring even when irradiated with radiation, and has found that the combination of thiodicarboxylic acid ester and a specific compound can achieve the above-mentioned goals. The inventors have discovered that this can be achieved, and have completed the present invention. That is, 0.001 to 10 parts by weight of a thiodicarboxylic acid ester compound and tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite per 100 parts by weight of polyolefin.
A radiation-resistant polyolefin composition characterized by containing 0.001 to 10 parts by weight of a thiodicarboxylic acid ester compound and 0.001 to 10 parts by weight of a thiodicarboxylic acid ester compound and tetrakis (2,4-di- tert-butylphenyl) 4,
This invention relates to a radiation-resistant polyolefin composition characterized in that it contains 0.001 to 10 parts by weight of 4'-biphenylene diphosphonite and 0.001 to 10 parts by weight of a phosphite compound. The thiodicarboxylic acid ester compounds used in the present invention have a carboxylic acid ester attached to a thio group, such as dilaurylthiodipropionate, distearylthiodipropionate, laurylstearylthiodipropionate, and dimyristylthiodipropionate. pionate and distearyl β,
Examples include β'-thiodibutyrate, which may be used alone or in combination of two or more. Among these, dilaurylthiodipropionate and distearylthiodipropionate are particularly preferred. The compound used in combination with the thiodicarboxylic acid ester compound is tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite. Furthermore, in the second invention, the phosphite compound used in combination with the above composition is represented by the following general formula (). (Here, R ₁ to _{R 3} are hydrogen, an alkyl group, a cycloalkyl group, or an aryl group, and each may be the same or different.) More specifically, trilauryl phosphite,
Trioctyl phosphite, triotadecyl phosphite, triphenyl phosphite, trinonylphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, dilauryl phosphite, distearyl pentaerythritol diphosphite, 4 , 4'-butylidene-bis(3-methyl-6-tert-butylphenyl)tridecylphosphite and 1,1,3-tris(2-methyl-4-di-tridecylphosphite-5-tert-butylphenyl) Examples include butane, which may be used alone or in combination of two or more. Among these, those in which all of R ₁ to _{R 3} are substituted with aryl groups are particularly preferred,
Tris(2,4-di-tert-butylphenyl) phosphite is particularly preferred among triphenyl phosphite, trinonylphenyl phosphite, and tris(2,4-di-tert-butylphenyl) phosphite. In the present invention, the combination of compounds blended into the polyolefin is a thiodicarboxylic acid ester and a phosphonite, or a thiodicarboxylic acid ester, a phosphonite, and a phosphite. The amount of each compounded thiodicarboxylic acid ester is 0.001 to 100 parts by weight of polyolefin.
10, especially 0.01 to 5 parts by weight of phosphonite
10, especially 0.01 to 5 parts by weight. When using phosphite in combination, the phosphite is 0.001 to 10
Add parts by weight. If the amount of each blended compound is outside the above range, radiation resistance may not be sufficient or bleed-out may occur, resulting in stickiness, which is not preferable. Examples of polyolefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene,
1-octene, 1-decene, 1-dodecene, 1-
Tetradecene, 1-octadecene, 3-methyl-
Homopolymers of α-olefins such as 1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, copolymers of two or more comonomers, and copolymers of α-olefins with other copolymers. Copolymers with possible monomers such as styrene, acrylonitrile, vinyl chloride, vinyl acetate, acrylic esters, methacrylic esters, etc., or alternatively blends with the above or with other thermoplastic resins, block copolymers. Any polyolefin such as a polymer or a graft copolymer may be used. The radiation-resistant polyolefin composition of the present invention may contain other known compounding agents, such as heat stabilizers,
Weathering stabilizers, halogen scavengers, antistatic agents, antiblocking agents, lubricants, dyes, pigments, inorganic/organic fillers, etc. may be added. Various methods can be used to obtain the composition of the present invention; for example, each component may be mixed using a ribbon blender, tumbler blender, Henschel mixer, etc., or the components may be mixed and then melt-mixed using an extruder, Banbury mixer, two rolls, etc. It is dissolved in a hydrocarbon or aromatic solvent and mixed into a polymer solution, and then used in a single screw extruder, vented extruder, two screw extruder, three screw extruder, conical double screw extruder, co-kneader, plastic extruder, etc. Teifuikata,
Extrusion molding, injection molding, blow molding, etc. are performed using mixtruders, twin-screw conical screw extruders, planetary screw extruders, gear type extruders, screwless extruders, etc. In particular, the composition of the present invention has little discoloration or deterioration of mechanical properties not only during irradiation with radiation but also when heated afterwards, and also has improved sanitary and toxic aspects such as hemolysis and cytotoxicity, making it suitable for medical treatment. It can be suitably used for utensils, food packaging materials, etc. Preferred examples of the present invention are shown below as Examples, but the present invention is not limited to these Examples unless otherwise specified. Example 1 Poly4-methyl-1-pentene (hereinafter referred to as P4MP)
100 parts by weight (Product name: Mitsui Petrochemical Industries TPX
RT18), dilauryl thiodipropionate (hereinafter referred to as compound A) 0.3 parts by weight, tetrakis (2,
0.1 part by weight of 4-di-tert-butylphenyl) 4,4'-biphenylene diphosphonite (hereinafter referred to as compound B) and 0.005 part by weight of calcium stearate as a halogen scavenger were measured using a measuring device. After stirring with a 25 Henschel mixer at low speed for 10 seconds and high speed for 30 seconds.
It was granulated using a 50mmφ granulator. Tensile test pieces (ASTM type) were made from this sample using an injection molding machine with a mold clamping pressure of 100 tons, and irradiated with radiation (gamma rays) at 2.5 megarads and 5 megarads. After that, it was placed in a gear oven at 60℃ to accelerate deterioration. After 10, 20, and 30 days, the samples were taken out and the haze value was measured using a Lab at Color Studio (Nippon Denshoku) and a haze meter (Nippon Denshoku). Further, mechanical properties were measured using an Instron measuring machine. The results are shown in Table 1. Lab measured the b value by stacking 10 2mm square plates. The larger the b value, the stronger the yellowness. Example 2 The same procedure as Example 1 was carried out except that 0.5 parts by weight of Compound A and 0.5 parts by weight of Compound B were added to 100 parts by weight of P4MP. The results are shown in Table 1. Example 3 1 part by weight of compound A for 100 parts by weight of P4MP,
The procedure was the same as in Example 1 except that 0.5 parts by weight of Compound B was added. The results are shown in Table 1. Example 4 In addition to Example 1, 0.2 parts by weight of tris(2,4-di-tert-butylphenyl) phosphite is added.
The rest was the same as in Example 1. Example 5 100 parts by weight of homopolypropylene (product name: Mitsui Petrochemical Polypropylene J700 manufactured by Mitsui Petrochemical Industries)
For distearyl thiodipropionate
Weigh out 0.5 parts by weight of tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite and 0.2 parts by weight. Other details were the same as in Example 1. Example 6 100 parts by weight of propylene copolymer (trade name: Mitsui Petrochemical Polypro F630, manufactured by Mitsui Petrochemical Industries)
For distearyl thiodipropionate
Weigh out 0.5 parts by weight of tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite and 0.3 parts by weight. Other details were the same as in Example 1. Comparative Example 1 Tetrakis[methylene(3,5
-di-tert-butyl-4-hydroxy)hydroxynamate]methane (Product name: Irganox
Weigh 0.2 parts by weight of 1010). Others are Example 1
I made it the same as Comparative Example 2 Tetrakis[methylene(3,5-
Weigh out 0.2 parts by weight of di-tert-butyl-4-hydroxy)hydroxynamate]methane. Other details were the same as in Example 1. The results are shown in Table 1. Comparative Example 3 Same as Example 1 except that compound B was removed from Example 1.
I made it the same as The results are shown in Table 1. Comparative Example 4 Example 6 except that compound A was removed from Example 6
I made it the same as The results are shown in Table 1.

[Table] □: No yellowing ○: Transparent △: Slight yellowing ×: Yellowing

【table】

Claims (1)

[Claims] 1. 0.001 to 10 parts by weight of a thiodicarboxylic acid ester compound and 0.001 parts by weight of tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite per 100 parts by weight of polyolefin.
A radiation-resistant polyolefin composition, characterized in that it contains ~10 parts by weight of a radiation-resistant polyolefin composition. 2 0.001 to 10 parts by weight of a thiodicarboxylic acid ester compound, tetrakis (2,4-di-tert-butylphenyl) per 100 parts by weight of polyolefin
4,4'-biphenylene diphosphonite 0.001~10
1. A radiation-resistant polyolefin composition, characterized in that it contains 0.001 to 10 parts by weight of a phosphite compound. 3. The thiodicarboxylic acid ester compound was selected from dilaurylthiodipropionate, distearylthiodipropionate, laurylstearylthiodipropionate, dimyristylthiodipropionate, and distearyl β,β′-thiodibutyrate. A radiation-resistant polyolefin composition according to claim 1. 4 The thiodicarboxylic acid ester compound was selected from dilaurylthiodipropionate, distearylthiodipropionate, laurylstearylthiodipropionate, dimyristylthiodipropionate, and distearyl β,β′-thiodibutyrate. The radiation-resistant polyolefin composition according to claim 2, which is a polyolefin composition. 5 Phosphite compounds include trilauryl phosphite, trioctyl phosphite, triotadecyl phosphite, triphenyl phosphite, trinonylphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, dilauryl phosphite , distearyl pentaerythritol diphosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl)tridecyl phosphite and 1,1,
The radiation-resistant polyolefin composition according to claim 2, which is selected from 3-tris(2-methyl-4-di-tridecylphosphite-5-tert-butylphenyl)butane.