JPH0249012A - Production of novel graft copolymer - Google Patents

Abstract

PURPOSE:To provide the subject hydrophilic copolymer having excellent anti- thrombogenic and substance-permeable properties and utilized for various catheters, etc., by graft-polymerizing polyethylene glycol mono(meth)acrylate ester to a vinyl polymer component containing vinyl chloride units. CONSTITUTION:A polyethylene glycol mono(meth)acrylate ester of the formula (R1 is H or CH3; R2 is H, CH3 or C2H5; n is >=5) is graft-polymerized to a vinyl polymer component containing vinyl chloride units to provide the objective copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a novel polyvinyl chloride copolymer.

[Prior art] Polyvinyl chloride resin has traditionally been widely used as a general-purpose resin in sheets, films, tubes, injection molded products, etc. due to its excellent and wide range of mechanical properties, good moldability, and economic efficiency. has been done. In order to use polyvinyl chloride for various purposes, it has been made into a copolymer with other components or added with various additives and plasticizers.

[Problems to be Solved by the Invention] An object of the present invention is to provide a method for producing a novel polyvinyl chloride polymer having even better performance.

[Means for Solving the Problems] That is, the present invention provides a monomer (A) represented by the formula % (wherein R1 is H or CH3, R2 is H1CH3 or C2H5, an integer of n≧5). , is a method for producing a novel graft copolymer, which comprises graft polymerizing a vinyl polymer component (B) containing vinyl chloride units.

The graft copolymer of the present invention is produced by producing polyethylene glycol monoacrylic acid or methacrylic acid ester as component A, and graft polymerizing this onto a vinyl polymer component (B) containing vinyl chloride units. Component B may be any vinyl polymer containing vinyl chloride units, such as vinyl chloride homopolymers, copolymers of vinyl chloride and vinyl acetate, and terpolymer copolymers of vinyl chloride, vinyl acetate, and ethylene. In the case of copolymers, poly(vinyl chloride) has a
In order to make the most of this characteristic, it is preferable to contain 10% by weight or more of vinyl chloride units.

Further, the polyethylene glycol monoacrylic acid or methacrylic acid ester used as component A can be obtained by transesterification of the corresponding polyethylene glycol and methyl acrylate or methyl methacrylate. For example, a compound in which R = R2 = CH3 can be obtained by transesterification of one-end methoxy polyethylene glycol obtained by adding ethylene oxide to methanol and methyl methacrylate. Here, the degree of polymerization n of the polyethylene glycol moiety is 5 or more, and preferably 5 to 200 for n.

As a method for grafting the acrylic acid and methacrylic acid ester monomer (A) thus obtained onto component B, A is heated in the presence of component B using a hydrogen abstracting radical initiator such as benzoyl peroxide. Although methods such as polymerization and chain transfer to obtain a graft polymer can also be used, so-called photografting involves introducing a photofunctional group into component B and grafting component A to component B using radicals generated from photolysis. In polymerization, it is possible to specify the amount, structure, position, etc. of active sites, and it is possible to obtain a graft polymer with a higher graft ratio with a better molecular design than the graft polymerization using chain transfer described above. This is the preferred method.

As such a photofunctional group, an N,N-dialkyldithiocarbamate group is preferable, and a diethyldithiocarbamate group (DTC group) is particularly preferable from the viewpoint of ease of introduction and stability of the product. DTC groups are easily incorporated into polymeric components containing vinyl chloride units. for example,
A photofunctional backbone polymer containing a DTC group (B' ) can be obtained.

Photograft polymerization of monomer A to component B' involves dissolving A and B' in a solvent such as tetrahydrofuran, dimethylformamide, or cyclohexanone, and irradiating light with a wavelength in the ultraviolet region using a high-pressure mercury lamp or the like under a stream of inert gas. This is easily done by irradiation.

Although the graft copolymerization ratio of component A and component B can be arbitrary, it is preferable that the copolymerization effect starts to appear when the former is 5% by weight or more, and more preferably 10% by weight.
That's all. A vinyl monomer component C copolymerizable with component A can be added within a range that satisfies this condition.

Examples of component C include methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, and 2-hydroxyethyl methacrylate, styrene, and vinyl acetate.

Thus, the graft copolymer obtained according to the present invention has different hydrophilic properties depending on the graft copolymerization ratio, and the equilibrium water content can be arbitrarily adjusted depending on the purpose.

In other words, as the A component increases, the hydrophilicity increases,
Equilibrium moisture content increases.

Further, the specific viscosity of the graft polymer obtained by the present invention is 0.
2 or more is preferable, and 0.5 or more is more preferable. Here, the specific viscosity refers to the specific viscosity measured at 25° C. of a solution prepared by dissolving the polymer of the present invention at a concentration of 1 g/100 ml in N,N-dimethylformamide as a solvent.

[Example] Examples are shown below.

Example 1 0.0 diethyldithiocarbamate group as photofunctional group
Polyvinyl chloride 5 with a degree of polymerization of 1100 containing 32 mol%
0 g and 50 g of methoxypolyethylene glycol methacrylate (M-9G) having polyethylene gelcol units with a degree of polymerization of 9 (n = 9) were dissolved in 500 g of tetrahydrofuran, and a light source internal immersion type photopolymerization device ( Using a high-pressure mercury lamp (UM-102, manufactured by Ushio Inc.) in a Ushio Inc. (ULO-6DQ), light was irradiated at 30°C for 8 hours under an argon stream to remove grafts of M-9G grafted onto polyvinyl chloride. A polymer was obtained.

The elemental analysis values of this graft polymer were as follows.

From this elemental analysis value, it was found that M-
It was found that 69.8% by weight of 9G was contained.

The obtained graft copolymer was dissolved in dimethylformamide and a film produced by a solvent casting method had a water content of 63.7%. The specific viscosity of this material is 0.83
Met.

Example 2 250 g of vinyl chloride-vinyl acetate-ethylene copolymer containing 0.05 mol% of diethyldithiocarbamate group (Nippon Zeon "Graftomer R3, vinyl chloride unit content 56 mol%) and a polymerization degree of 23 (n- 23) and 150 g of methoxypolyethylene glycol methacrylate (M-23G) having polyethylene glycol units.
g of cyclohexanone and 10 cm from the reaction vessel.
Using a 450W high-pressure mercury lamp (manufactured by Ushio Inc., UM-452) installed at a distance of A copolymer was obtained.

The elemental analysis values of this gutt copolymer were as follows.

From this elemental analysis value, it was found that M-
It was found that 29.2% by weight of 23G was contained.

The specific viscosity of this product was 1.2.

Example 3 The graft copolymer prepared in Example 1 was dissolved in N,N-dimethylformamide at a concentration of 5%, and used as a core material with a diameter of 1.5%. A tube was created by a dipping method using a stainless steel rod with a diameter of 5 mm and a length of about 30 cm. This tube was extracted in methanol and water at 60° C. for 3 days each, then vacuum dried and further sterilized with ethylene oxide gas.

An adult (approximately 15 kg) was anesthetized by intravenously injecting bendoparbital soda, the stepped vein was incised, a tube was inserted from the incision to the vicinity of the right atrium inflow of the vena cava, and the tube was left in place for 5 days. After removal of blood, the laparotomy was performed to open the engineered vena cava, and as a result of observing the state of thrombus adhesion on the surface of the material, almost no thrombus was observed on the surface of the graft made of the graft copolymer of the present invention, indicating that this material is superior. It was found that the material exhibited antithrombotic properties and had properties useful as a medical material.

[Effects of the Invention] The graft copolymer obtained by the present invention is hydrophilic and has excellent antithrombotic properties and substance permeability, so it can be used as medical materials such as various catheters and blood circuits, electrophoresis and liquid chromatography. It can be used as a carrier for graphics, various coating agents for antifouling and antifogging purposes, food packaging materials, selectively permeable membranes, etc.

Claims (1)

[Claims] (1) Formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 is H or CH_3, R_2 is H, CH
_3 or C_2H_5, an integer of n≧5) is graft-polymerized to a vinyl polymer component (B) containing vinyl chloride units. .