JPH039125B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved medical soft vinyl chloride resin material. Currently, medical equipment made from soft vinyl chloride resin materials, such as blood transfusion sets, infusion sets,
Blood bags, catheters, tubes, etc. are used. The performance required for such equipment is that it has heat resistance that can withstand sterilization using high-pressure steam, that it can be easily thermally bonded, and that blood and infusion fluids do not change in quality and remain intact even after long periods of contact. In addition, it must not transfer foreign substances into the blood or absorb certain components of blood or transfusions. However, although the above-mentioned soft vinyl chloride resin material satisfies the above-mentioned performance to some extent, it contains liquid low-molecular-weight plasticizers such as phthalate ester compounds, especially dioctyl phthalate (DOP), so such plasticizers may be present in the blood. It easily migrates or elutes, which poses a problem for long-term use. Thermoplastic elastomers such as ethylene/vinyl acetate copolymers, thermoplastic SBRs, and ethylene/acrylic acid ester copolymers have recently been considered as products that do not have these drawbacks, but polymers with crystallinity in particular are being considered. Because the molded product is deformed during steam sterilization, it tends to have poor heat resistance. or,
Compared to the vinyl chloride resin/dioctyl phthalate system, it has a rubber-like feel, making it undesirable especially for medical tubes, and it has not been put into practical use yet. Currently, vinyl chloride resin/
No material that is superior enough to replace dioctyl phthalate has yet to be obtained. The inventor of the present invention attempted to develop a superior medical soft vinyl chloride resin material, and found that vinyl ester/
Grafting vinyl chloride monomer in the presence of ethylene copolymer and thermoplastic polyurethane, and
The soft vinyl chloride resin material treated with hot water at 80 to 150 degrees Celsius has passed the Japanese Pharmacopoeia Law's "Infusion Plastic Container Test Method," and has sufficient heat resistance, welder adhesion, and transparency to withstand high-pressure steam sterilization. The present invention has been accomplished by obtaining an improved medical soft vinyl chloride resin material that has a similar feel to vinyl chloride resin/dioctyl phthalate and also passes a cytotoxicity test. The present invention relates to (A) vinyl ester/ethylene copolymer
In the presence of 40 to 70 parts by weight and (B) 60 to 30 parts by weight of thermoplastic polyurethane, (C) a vinyl chloride monomer or a mixture of this monomer and other vinyl monomers copolymerizable with it.
30 to 70% by weight (based on the vinyl chloride graft copolymer) of a vinyl chloride graft copolymer obtained by hot water treatment to provide a medical soft vinyl chloride resin material. be. Vinyl esters that are constituent components of the vinyl ester/ethylene copolymer used in the present invention include vinyl acetate, vinyl propionate, vinyl versatate, and vinyl benzoate. Of course, there is no problem in using other vinyl monomers that can be copolymerized with ethylene or vinyl esters, and (meth)acrylic acid or esterified products thereof are representative examples. It will be done. In addition, the vinyl ester/ethylene copolymer preferably has a Mooney viscosity of about 5 to 40 from the viewpoint of processability, and in addition, considering the transparency and welder adhesion of the resin material of the present invention, the vinyl ester content is preferably 80 to 50% by weight. is preferred. In the present invention, the vinyl ester/ethylene copolymer and thermoplastic polyurethane are
parts by weight, the latter in a proportion of 60 to 30 parts by weight, and the amount of vinyl ester/ethylene copolymer is less than 40 parts by weight (40 parts by weight relative to the total with thermoplastic polyurethane).
If it is (less than % by weight), the urethane component will be large, resulting in poor hydrolyzability, heat resistance, and transparency when the resin material of the present invention is treated with hot water, and moreover, the color will change to yellow. On the other hand, if the amount exceeds 70 parts by weight (70% by weight based on the total amount including the thermoplastic polyurethane), the resin becomes hard and the effect of improving physical properties such as low temperature properties cannot be sufficiently achieved. On the other hand, the thermoplastic polyurethane as the backbone polymer usually has a number average molecular weight of 300 or more, preferably
500 or more, and refers to those obtained by the reaction of long chain glycols having OH groups at both ends with polyisocyanate compounds having NCO groups at both ends. Representative long-chain glycols include polyether glycols obtained by polymerizing alkylene oxides such as propylene oxide or tetrahydrofuran; polyether glycols obtained by polymerizing adipic acid and glycols such as ethylene glycol or propylene glycol; There are polyester glycols obtained by condensation and polyester glycols obtained by ring-opening polymerization of lactones. Typical polyisocyanate compounds include toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and naphthylene diisocyanate. There are isocyanates, etc. The graft polymerization of the vinyl chloride monomer or a mixture of this monomer and other monomers in the present invention takes place at the acetoxy group of the vinyl ester/ethylene copolymer and at the active part of the main chain of the thermoplastic polyurethane. The thermal stability of each polymer to be grafted tends to be improved by grafting vinyl chloride monomer or the like. The above-mentioned graft polymerization monomer (grafting monomer) as a grafting component includes vinyl chloride alone and monomers copolymerizable with vinyl chloride, such as vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl stearate. Acrylic monomers such as esters of acrylic acid, methacrylic acid or α-chloroacrylic acid and monovalent saturated aliphatic alcohols having 1 to 10 carbon atoms, typical Examples include methyl, ethyl, propyl, isopropyl, n-butyl, t
-butyl, 2-ethylhexyl acrylate or methacrylate; also vinylidene chloride,
Vinylpyrrolidene, styrene, α-methylstyrene, ring-substituted methyl or ethylstyrene, acrylonitrile, methacrylonitrile, lower alkyl vinyl or isopropenyl ethers and ketones of alkyl groups having 1 to 4 carbon atoms, and ethylene, propylene, butylene, isobutylene , 1-pentene, 1-hexene, and other terminally unsaturated monoolefins having 2 to about 6 carbon atoms (the terminally unsaturated monoolefin may be linear or have a side chain). The amount of copolymerizable monomers other than the vinyl chloride monomer used is usually 50% by weight or less, preferably 15% by weight or less, based on the total monomer mixture. In this way, in the method of the present invention, vinyl chloride alone or a mixture of vinyl chloride and other copolymerizable vinyl monomers,
By radical polymerizing a mixture of the ethylene-vinyl ester copolymer and thermoplastic polyurethane as the backbone polymer, a vinyl chloride polymer containing a graft polymer of each of these backbone polymers can be obtained, but the method of the present invention When performing this, the amount of such grafting monomer used is 30 to 30% of the target resin, the vinyl chloride graft copolymer.
It is in the range of 70% by weight, preferably 40-60% by weight. That is, when carrying out the method of the present invention, in the presence of the mixture of each of the above-mentioned backbone polymers, the amount of the grafted monomer is 30 to 30% based on the weight of the desired vinyl chloride graft copolymer to be obtained. Radical polymerization is carried out using a known and commonly used radical polymerization initiator at a concentration of 70% by weight,
The polymerization formation at this time may be in the form of a lump, solution, emulsification or suspension, but in particular,
Industrially, suspension polymerization is advantageous. Typical polymerization initiators used include organic peroxides such as lauroyl peroxide, benzoyl peroxide, and diisopropyl peroxydicarbonate; organic azo compounds such as azobisisobutyronitrile; or hydrogen peroxide; These include inorganic peroxides such as ammonium persulfate; or redox catalyst systems in which these peroxides are combined with various reducing agents such as sodium sulfite or ferrous sulfate. In addition, although there is no particular restriction on the polymerization temperature,
A range of ~100°C is preferable. The medical soft vinyl chloride resin material used in the present invention is obtained by graft polymerizing vinyl chloride monomer etc. in the presence of a polymer consisting of a vinyl ester/ethylene copolymer and a thermoplastic polyurethane, and then
Those treated with hot water at 150°C are preferred, and usually only the vinyl ester/ethylene copolymer and thermoplastic polyurethane grafted with vinyl chloride monomer etc. are removed from the solvent used during polymerization. Subjected to hot water treatment. For example, in the case of emulsion polymerization, salt is added and heated to coagulate, in the case of suspension polymerization, components other than the polymer are removed by filtration separation, and in the case of solution polymerization, components other than the polymer are removed by desolvent, and then water is added. In an autoclave heated to ℃, water-soluble components such as auxiliary agents added during polymerization are dissolved and removed, and at the same time unstable and easily decomposed parts present in the polymer are decomposed and stabilized. The one obtained by the method is preferable. The amount of water during hot water treatment is 1 to 10% of the amount of polymer.
It is preferable to use about twice the weight, and the temperature of the hot water is 110 to 140.
°C is preferred. Incidentally, the hot water treatment may normally be carried out once, but if the plastic container test for infusions is not passed, the treatment may be carried out two or more times without causing any problem in the physical properties of the resulting resin material. In the present invention, a stabilizer can be added to the vinyl chloride graft copolymer in order to improve its heat aging resistance during processing. Calcium stearate, zinc stearate, etc. are effective as stabilizers in this case, and addition of epoxidized soybean oil is practically useful. Furthermore, the resin material of the present invention includes polyvinyl chloride resin; vinyl chloride/ethylene copolymer; vinyl chloride/vinyl acetate copolymer; ethylene/acrylic acid ester copolymer, ethylene/carbon monoxide/vinyl acetate copolymer. , vinyl chloride grafted ethylene/vinyl acetate copolymer, vinyl chloride grafted chlorinated polyethylene polymer, vinyl chloride grafted acrylic rubber, vinyl chloride grafted ethylene/acrylic acid ester copolymer, vinyl chloride grafted ethylene/propylene A graft copolymer of vinyl chloride to a thermoplastic elastomer such as a copolymer may be mixed as long as the object of the present invention is not impaired, and the preferred amount thereof is up to 30% by weight. The medical soft vinyl chloride resin material of the present invention is
Because it is treated with hot water to remove soluble components and easily decomposable substances, it has excellent flexibility, hydrolyzability, transparency, and welding processability, and is a vinyl chloride resin / dioctyl phthalate medical soft vinyl chloride type. It has a feel (texture) that is very similar to the material, and passes the tests for plastic containers for infusions, and can be used as a single item or as a medical soft vinyl chloride material for infusion sets, blood transfusion sets, medical bandages, etc. Lamination with a general-purpose plastic film, such as an ethylene/vinyl acetate copolymer film, is extremely useful in practice. The present invention will be specifically described below with reference to Examples. Note that parts and percentages in the examples are based on weight. Example 1 After replacing the pressure polymerization vessel with nitrogen gas with a stirrer, vinyl acetate/ethylene copolymer (60/
Polyurethane 100 obtained by polymerizing 1,4-butanediol/adipic acid polyester polyol with a number average molecular weight of 1200 and hexamethylene diisocyanate in an equivalent ratio of 1:1. part, vinyl chloride monomer
250 parts, α,α′-azobisisobutyronitrile 1
1 part, 2 parts of polyvinyl alcohol, and 850 parts of water were charged and stirred at room temperature for 5 hours to melt the polymer into vinyl chloride. Next, polymerization was carried out at 70 to 80° C. for 15 hours to remove unreacted materials and obtain a suspended vinyl chloride graft copolymer. This slurry was filtered to separate and wash the polymer, and then transferred to a pressure-resistant reaction vessel.
Next, 2000 ml of water was added and treated with stirring at 130°C for 60 minutes. The obtained suspended vinyl chloride graft copolymer was filtered and the polymer content was dried at 60°C to obtain 375 parts of the target resin in powder form. Obtained. To this resin, 100 parts of toluene was added and treated in an Erlenmeyer flask equipped with a reflux condenser at 80 to 85°C for 5 hours, and 3.6 parts of undissolved resin was filtered off. or,
When the nitrogen content of the polymer dissolved in toluene was measured by the Kjeldahl method, 1.0 part of raw material polyurethane was detected, and the remaining polymer was 0.4 part of vinyl acetate/ethylene copolymer. As a result, the grafted resin contained 64% of the raw materials polyurethane and vinyl acetate/ethylene copolymer. Said vinyl chloride graft copolymer powder
100 parts contains 0.5 parts of calcium stearate, 0.5 parts of zinc stearate, and 5 parts of epoxidized soybean oil.
The mixture was kneaded with rolls at 120°C for 5 minutes to form a press sheet with a thickness of 0.5 mm. This sheet has been tested for leachables according to the "Plastic Container Test Method for Ring Liquors" in the Japanese Pharmacopoeia Law, including appearance evaporation residue, foaming, PH change, permanganate consumption, and ultraviolet absorption spectrum (220-240 nm, 241 nm).
~350nm) Passed the chloride and hemolytic tests, as well as the cytotoxicity test. The basic physical properties of the polymer are shown in Table 1. Examples 2 to 3, Comparative Examples 1 to 5 In Example 1, the types of vinyl acetate/ethylene copolymer, thermoplastic polyurethane, and vinyl chloride,
Polymerization, heat treatment, and processing were carried out in exactly the same manner as in Example 1, except for changing the amount. Among the obtained sheets, those of the present invention passed the above test according to the Japanese Pharmacopoeia Law. The physical properties of each polymer are summarized in Table 1. Comparative Example 6 A sheet obtained in the same manner as in Example 1 except that no heat treatment was performed failed the plastic infusion container test and showed hemolytic action. Example 4 Powdered resin synthesized in Example 1
A film processed by mixing 100 parts with 20 parts of vinyl chloride/ethylene copolymer (7% ethylene) is
The 100% modulus is 95Kg/cm ² , which makes it a little harder.
Passed the plastic container test for infusion, heat resistance,
Processing was possible without any particular problem with welder adhesion. As shown in Table 1, Comparative Examples 2 and 3 were hard and had poor low-temperature embrittlement, and Comparative Examples 1, 4, and 5 had poor heat resistance, whereas all of the Examples were excellent. .

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Claims (1)

[Claims] 1 (A) Vinyl ester/ethylene copolymer
40 to 70 parts by weight and (B) thermoplastic polyurethane
In the presence of 60 to 30 parts by weight, (C) a vinyl chloride monomer or a mixture of this monomer and other vinyl monomers copolymerizable with it;
A medical soft vinyl chloride resin material obtained by hot water treatment of a vinyl chloride graft copolymer obtained by reacting 30 to 70% by weight (based on the vinyl chloride graft copolymer).