JPS6346776B2 - - Google Patents

Description

[Detailed description of the invention]

[]Object of the Invention The present invention is a composition consisting essentially of chlorinated polyethylene and low molecular weight polyethylene, and an object of the present invention is to provide a chlorinated polyethylene composition suitable for medical devices. [] Background of the Invention For some time now, crosslinking agents, vulcanizing agents, vulcanization accelerators, and vulcanization accelerators have been used in thermoplastic resin compositions and elastomers obtained by blending lubricants, plasticizers, etc. with thermoplastic resins. Rubber elastic compositions, such as plastic and rubber products, obtained by vulcanization or crosslinking by heat treatment with additives such as anti-oxidants and anti-aging agents are used in medical devices. It is well known that Japan contributes greatly to the maintenance and improvement of health and hygiene. However, thermoplastic resin compositions with high rigidity contain large amounts of plasticizers, stabilizers, etc. in order to produce appropriate flexibility and stability against heat. As a result, plasticizers, stabilizers, etc. bleed out, creating a safety problem. On the other hand, since the elastomer itself has double bonds, rubber elastic compositions also have heat resistance,
Weather resistance needs to be improved. For this purpose, anti-aging agents are added, but not only do anti-aging agents bleed out, but the process of creating a vulcanized (cross-linked) product using a vulcanizing agent (cross-linking agent) is required. is necessary. Moreover, if the product is used for a long period of time, it has drawbacks such as a decrease in rubber elasticity due to deterioration of the elastomer. For these reasons, both thermoplastic resin compositions and rubber elastomer compositions naturally have limitations in terms of use. [] Structure of the Invention Based on the above, the present inventors have conducted various searches to obtain a composition suitable for medical devices, and found that the composition consists essentially of chlorinated polyethylene and low molecular weight polyethylene, and that the composition consists essentially of chlorinated polyethylene and low molecular weight polyethylene. We have discovered that a chlorinated polyethylene composition in which the proportion of chlorinated polyethylene in the total amount of molecular weight polyethylene is 80 to 97% by weight is a composition suitable for medical devices,
We have arrived at the present invention. [] Effects of the Invention The chlorinated polyethylene composition obtained by the present invention exhibits the following effects (characteristics). (1) Good heat resistance and flexibility. (2) Has weather resistance. (3) The dimensional accuracy of the molded product is excellent. (4) Not only does it have good moldability, but it also has a low shrinkage rate during molding. (5) By adding a nucleating agent, molded products with excellent transparency can be obtained. (6) There is almost no shrinkage even after sterilization. (7) The elastic modulus of the molded product is low. The composition obtained by the present invention has the above-mentioned excellent effects and can be used in a wide variety of fields. In particular, it holds promise as a medical device. Its uses are shown below. (1) Medical equipment such as blood, infusions, blood transfusions, and blood collection sets; (2) Conduits for blood, body fluids, drugs, blood transfusions, blood collection, and infusions; Medical devices used (5) Bags for infusions, blood transfusions, etc. [] Detailed description of the invention (A) Chlorinated polyethylene The chlorinated polyethylene used in the present invention is obtained by chlorinating polyethylene powder or particles in an aqueous suspension. Alternatively, it can be obtained by chlorinating polyethylene dissolved in an organic solvent (preferably by chlorinating it in an aqueous suspension). In general, amorphous or crystalline chlorinated polyethylene with a chlorine content of 20 to 50% by weight is preferred, and amorphous or crystalline chlorinated polyethylene with a chlorine content of 25 to 45% by weight is particularly preferred. . The polyethylene is obtained by homopolymerizing ethylene or copolymerizing ethylene with at most 10% by weight of α-olefin (generally having at most 6 carbon atoms). Its density is generally between 0.910 and 0.970 g/cc. Moreover, its molecular weight is 50,000 to 700,000. In producing the composition of the present invention, only chlorinated polyethylene may be used, but other types of polymeric substances that are miscible with chlorinated polyethylene may also be blended. The polymer substance includes natural rubber,
Rubbery materials such as butadiene homopolymer rubber, styrene-butadiene random or block copolymer rubber (SBR), and acrylonitrile-butadiene copolymer rubber, and vinyl chloride resins whose main component is vinyl chloride (the degree of polymerization is generally 600 to
1800). The Mooney viscosity (ML ₁₊₄ ) of the rubbery material is 10-150.
Regarding these rubber-like substances and resin-like substances, please refer to “Synthetic Rubber Handbook” edited by Kambara et al. (Asakura Shoten,
It is well known from books such as "Plastic Handbook" edited by Murahashi et al. (published by Asakura Shoten, published in 1962), etc. When these polymeric substances are blended, the blending ratio is at most 30 parts by weight based on the chlorinated polyethylene. (B) Low molecular weight polyethylene The molecular weight of the low molecular weight polyethylene used in the present invention is generally from 300 to 10,000, and preferably from 1,500 to 9,000. The low molecular weight polyethylene is a milky white, translucent powder, pellet or liquid. This low molecular weight polyethylene can be broadly classified into (1) a wax type with a softening point of 50 to 120°C and a specific gravity of 0.85 to 0.95, and (2) a wax type with a softening point of 100 to 140°C and a specific gravity of 0.90 to 0.95. A certain emulsion type (3) has a softening point of 60 to 110℃ and a specific gravity of 0.90 to
copolymer type whose softening point is 0.95 and (4)
There is an oxidized homopolymer type that has a temperature of 100 to 140°C and a specific gravity of 0.90 to 1.00. Regarding these low molecular weight polyethylenes, please refer to "Handbook of Rubber/Plastic Compounded Chemicals" edited by Rubber Digest Co., Ltd.
(Rubber Digest Co., published in 1971) No. 303~
Their manufacturing methods and physical properties are described in pages 325 and 96 to 102 of "Fine Polymers & Engineering Plastics" (Kagaku Kogyo Nippo Publishing Co., Ltd., published in 1978), and are well known. It is something. (C) Nucleating agent Although the composition of the present invention can be obtained by mixing chlorinated polyethylene and low molecular weight polyethylene, transparency can be imparted by further adding a nucleating agent. be. The nucleating agent is generally used as a gelling accelerator for resins, and changes the spherulite structure of the resin. In other words, it is a compound that envelops resin crystals and imparts transparency so that a large number of small crystals are dispersed. Representative examples of this compound include organic carboxylic acids, aluminum salts of organic carboxylic acids, dibenzylidene sorbitol talc, unsaturated fatty acid amides, and metal salts of stearic acid and tobiloxystearic acid. (D) Stabilizer Generally, when chlorinated polyethylene is exposed to light, heat during melt-kneading, processing, and use for a long period of time, it undergoes dehydrochlorination, discoloration, and deterioration. A stabilizer (dehydrochlorination inhibitor) known as a stabilizer is added to the solution. When the composition of the present invention is used as a medical device, the use of stabilizers harmful to the human body (eg, cadmium stearate, tin-containing compounds, lead-based compounds) should be avoided. For the above reasons, metal soaps (for example, calcium stearate), epoxy derivatives, and composite stabilizers (powder, paste, liquid) that are harmless to the human body are used. These stabilizers are well known from pages 266 to 297 of the aforementioned "Handbook of Rubber and Plastic Compounded Chemicals." (E) Blending ratio In the composition of the present invention, the blending ratio of chlorinated polyethylene in the total amount of chlorinated polyethylene and low molecular weight polyethylene is 80 to 97% by weight, particularly preferably 80 to 95% by weight. If the proportion of chlorinated polyethylene in the total amount is less than 80% by weight, the heat resistance of the resulting composition will decrease. On the other hand, if the amount is 97% by weight or more, it is impossible to obtain a composition with excellent shrinkage stability in terms of processability and heat resistance during molding. As mentioned above, transparency can be improved by further adding the nucleating agent to the composition. It is generally at most 5 parts by weight, and generally 3 parts by weight or less is sufficient, based on 100 parts by weight of the total amount of chlorinated polyethylene and low molecular weight polyethylene. In addition, stabilizers added to improve heat and light stability are generally added in a total amount of 100% of the chlorinated polyethylene and low molecular weight polyethylene.
It is usually added in an amount of 10 parts by weight or less. Furthermore, 0.1 part by weight or more is added to exhibit sufficient stability. Particularly desirable is 0.5 to 5 parts by weight. (F) Manufacturing and molding method of chlorinated polyethylene composition Although the composition of the present invention can be obtained by uniformly blending the above substances, it is possible to obtain the composition of the present invention by uniformly blending the above substances. Additives such as release agents, oxygen, ozone and light (ultraviolet) stabilizers, binders, lubricants and colorants may be added depending on the intended use of the composition. In addition, sulfur vulcanizing agents, sulfur-releasing compound-based vulcanizing agents, amine-based vulcanizing agents, organic peroxide-based crosslinking agents, and organic peroxide-based crosslinking coagents commonly used in the rubber industry and resin industry, etc. Additives may be added depending on the intended use of the composition. When producing the composition of the present invention, the blending (mixing) method may be to use a mixer commonly used in the art, such as an open roll, dry blender, Banbury mixer, and kneader. Among these mixing methods, in order to obtain a more uniform composition, two or more of these mixing methods may be applied (for example, after mixing in advance with a dry blender, the mixture may be mixed using an open roll). how to). The composition of the present invention may be molded into a desired shape using molding machines commonly used in the rubber industry, such as extrusion molding machines, injection molding machines, compression molding machines, and calender molding machines. In addition, a method of manufacturing a molded product by adding chlorinated polyethylene or the above-mentioned composition and vulcanizing (crosslinking) it in the rubber technology field, that is, a method of simultaneously proceeding vulcanization and molding, is applied. It may be formed into a desired shape. [] Examples and Comparative Examples The present invention will be explained in more detail below using Examples. In addition, in the examples and comparative examples, the tensile test was measured according to JIS K-6301. The elastic modulus test was performed using a Tensilon measuring machine (manufactured by Toyo Seiki Co., Ltd.) under conditions of a tensile speed of 5 mm/min and a chart speed of 600 mm/min. Furthermore, in the autoclaveability test, the shrinkage rate of the sample was measured using a retort processing device at a temperature of 121° C. and a time of 20 minutes. In addition, transparency (HAZE) was measured using a transparency meter (Clarity Meter TM-ID). The ingredients used in the Examples and Comparative Examples have the following manufacturing methods, shapes, and physical properties, respectively. [Chlorinated polyethylene] As chlorinated polyethylene, the density is 0.950g/cm ³
By chlorinating polyethylene (average molecular weight approximately 250,000) using an aqueous suspension method, amorphous chlorinated polyethylene with a chlorine content of 40.4% by weight [hereinafter referred to as "CPE (1)"] ] and the density is
Polyethylene with an average molecular weight of 0.926g/ ^cm3 (average molecular weight approximately 10
A crystalline chlorinated polyethylene (hereinafter referred to as "CPE(2)") having a chlorine content of 30.2% by weight was used by chlorinating CPE(2) by an aqueous suspension method. [Low molecular weight polyethylene] Also, as a low molecular weight polyethylene, the softening point is
Low molecular weight homopolymer [density
0.940g/cm ³ , hereinafter referred to as "LPE(a)"], the softening point is
Oxidized homopolymer with a temperature of 104℃ [density 0.930g/cm ³ ,
A low molecular weight ethylene monovinyl acetate copolymer (density 0.920 g/cm ³ , hereinafter referred to as "LPE(C)") having a softening point of 95° C. was used. [Rubber-like material] Furthermore, a styrene-butadiene block copolymer rubber (styrene content: 25.0% by weight, hereinafter referred to as "SBR") having a Mooney viscosity (ML ₁₊₄ ) of 60 was used as the rubber-like material. [Thermoplastic resin] Also, as a thermoplastic resin, vinyl chloride homopolymer (hereinafter referred to as "PVC") with a degree of polymerization of approximately 700 is used.
was used. [Stabilizer] Furthermore, as a stabilizer, epoxidized soybean oil with a molecular weight of approximately 1000 [manufactured by Adeka Argus Co., Ltd.] is used. Product name ADEKA Sizer 0-130S, specific gravity 0.982~
1.002, hereinafter referred to as ``stabilizer (1)''] and calcium-zinc complex [manufactured by ADEKA ARGUS, trade name ADEKA MARK AO-40, specific gravity 2.3, hereinafter referred to as ``stabilizer (2)'']. . [Nucleating agent] In addition, dibenzylidene sorbitol (manufactured by Eshi Chemical Co., Ltd., trade name EC-1, decomposition temperature 230° C. or less, referred to as "DBS") having a melting point of 208 to 210° C. was used as a nucleating agent. Examples 1 to 3, Comparative Examples 1 to 6 As the above composition components, “chlorinated polyethylene,
rubber-like materials, thermoplastic resins” (hereinafter referred to as “chlorinated polyethylene, etc.”), low molecular weight polyethylene,
The stabilizer and nucleating agent were mixed in the amounts shown in Table 1 (all parts by weight) for 10 minutes using a roll preset at 50°C. A mixture (composition) was produced by melt-kneading each of the obtained mixtures using a kneader at a temperature range of 100 to 130°C. Each composition was further melt-kneaded using a mixing roll to create a sheet. A pulverized product was prepared by pulverizing each of the sheets thus obtained. Each sheet was extruded using an extruder (tube shape with a die diameter of 4 mm, diameter 32 mm, L/
D20) was used to manufacture tubes under the following conditions: cylinder 1 temperature 130°C, cylinder 2 temperature 150°C, die temperature 180°C, and rotation speed 30 rpm. Tensile test and elastic modulus test of each tube obtained. Autoclave tests and clarity tests were conducted. The results obtained are shown in Table 2.

【table】

【table】

[Table] In Comparative Example 6, dehydrochlorination occurred during extrusion molding to produce tubes, and tubes could not be produced.

Claims (1)

[Claims] 1. A chlorinated polyethylene composition consisting essentially of chlorinated polyethylene and low molecular weight polyethylene, wherein the proportion of the chlorinated polyethylene in the total amount of the chlorinated polyethylene and the low molecular weight polyethylene is 80 to 97% by weight.