JPS604849B2 - Method for manufacturing hydrophilic medical hard plastic molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, most of the plastics used for medical purposes are lipophilic and have poor wettability with water, blood, and the like.

An exceptional hydrophilic plastic is polyvinyl alcohol aldehyde (called poval), which is soft. Polyvinyl chloride resin (polyvinyl chloride resin plasticized with a plasticizer) is hydrophilic, but this is also a European quality. Non-hydrophilic plastics have certain advantages in medical applications, but they can also be used in areas where wettability with blood is important, such as the disks and capillaries of rotating disk oxygenators, and where the internal parts become cloudy due to condensation of water vapor. In applications where loss of permeability is a problem, such as cases for various artificial organs and medical devices that keep blood warm and circulate, hydrophilicity is strongly required, and in these applications, it may be difficult to make it soft when molded. It is customary.

There are many hydrophilic polymers, but many are hydrophilic;
Those made water-insoluble by crosslinking, such as polyhydroxylalkyl methacrylate, are normally hard, but when they come into contact with water, they absorb water and become soft, resulting in a significant decrease in strength. In addition, hydrophilic monomer
Copolymerization of oleophilic polymers with monomers forming lipophilic hard plastics or blending of hydrophilic polymers with lipophilic hard plastics may also be considered, but these polymers with homogeneously dispersed hydrophilic groups are When a hydrophilic group is introduced in an amount that exhibits sufficient hydrophilicity, there is a problem that it swells upon contact with water, reduces strength, and becomes unusable for the above-mentioned purposes. As a result of searching for various plastics that can be used for these purposes, the present inventors have found that by introducing sulfate or sulfonic acid groups into the surface of molded plastics, they can be made hydrophilic to achieve the desired purpose. I saw what would be achieved and put it out there.

That is, the present invention is a method for producing a molded product having sufficient hydrophilicity for practical use by sulfating or sulfonating the surface of hard plastics containing double bonds. The amount of this heavy bond required for this hydrophilicity is preferably 1 mol% or more, preferably 2 mol% or more, calculated in terms of the monomer having a conjugated double bond, and if this amount is excessive, Since the produced polymer is flexible, it becomes a molded product like a soft card and cannot be used for the purpose of the present invention, so the amount is 20 mol % based on the monomer having conjugated double bonds. Must be less than or equal to Specific hard plastics having conjugated double bonds that can be used in the present invention include polybutadiene-styrene graft polymers, polybutadiene-styrene acrylonitrile graft polymers,
Styrene/putadiene copolymer - styrene graft polymer, styrene/putadiene copolymer - styrene/acrylonitrile graft polymer, styrene/butadiene copolymer - styrene/methyl methacrylate graft polymer,
Acrylonitrile/putadiene copolymer - acrylonitrile/acrylic acid ester graft polymer, putadiene/acrylonitrile/styrene copolymer, putadiene/
Styrene copolymer, butadiene/methyl methacrylate copolymer, isoprene/acrylonitrile/styrene copolymer, isoprene/styrene copolymer, 1,3-pentadiene/styrene copolymer, 1,3-bentadiene/styrene copolymer,
Examples include styrene/acrylonitrile copolymer.

The sulfation reaction in the present invention is carried out by immersing a molded hard plastic having double bonds in concentrated sulfuric acid heated at room temperature or at a temperature at which the plastic will not be deformed under the processing conditions of the plastic.

It is also possible to use fuming sulfuric acid. In the above process, it is also possible to reduce the sulfuric acid concentration by using chromic anhydride in combination. Further, the sulfonation reaction can be carried out by diluting the molded hard plastic having double bonds in fuming sulfuric acid or chlorosulfonic acid at a concentration of 50 oo or less. After treatment with these acids, it may be sufficient to simply wash with water, or, if necessary, it may be neutralized with alkali IJ to form a salt of these acids. Example 1 A polymer obtained by grafting 20 parts by weight of acrylonitrile and 8 parts by weight of styrene to parts by weight of polybutadiene 1 was molded into two plates, washed, and one of them was dried to form a 40q.
98% sulfuric acid for 20 minutes, and then washed with water.

The treated specimen and the untreated specimen were each immersed in distilled water and gently pulled out.

There were only a few water droplets adhering to the surface of the untreated pieces, but a film of water was attached to the entire surface of the treated pieces. Example 2 A polymer obtained by graft polymerizing 95 parts by weight of styrene to 5 parts by weight of a copolymer of 25% by weight of styrene and 75% by weight of butadiene was molded into two plates, and after washing, one of the plates was dried and kept at room temperature. The sample was soaked in chlorosulfonic acid for 10 minutes, then washed with water, neutralized by soaking in a 5% aqueous solution of caustic soda, and further washed with water.

The treated specimen and the untreated mystery specimen were each immersed in distilled water, and both were gently pulled out.

Claims (1)

[Claims] 1 Monomers with conjugated double bonds are added to the total monomers from 1 to 1.
1. A method for producing a hydrophilic medical hard plastic molded article, which comprises bringing the surface of a hard plastic molded article made of a polymer containing 20 mol% into contact with sulfuric acid to sulfate or fulfionize the surface.