JPS5818364B2 - Kakiyoji Yugo Taisoseibutsu no Seizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a novel crosslinked polymer composition, and more specifically to a method for producing a novel crosslinked polymer composition, which provides a highly water-containing, transparent, and highly strong hydrogel, and has excellent polymerization formability. The purpose is to produce crosslinked polymer compositions.

In recent years, as the use of polymeric materials in the medical industry has progressed, interest in hydrophilic polymers (water-insoluble,
In addition, polymeric materials with large water-absorbing capacities have been tested or used as embedding materials for various membranes, catheters, cannulae, contact lenses, blood storage containers, enzyme medicines, etc.

However, in most of these hydrogels, the mechanical properties rapidly decrease as the water content increases, or transparency is lost when trying to increase permeability to substances (water, oxygen, etc.). It is no exaggeration to say that until now there have been few hydrogels that simultaneously satisfy mechanical properties, optical properties, and material permeability.

The present inventors conducted intensive studies to discover a new crosslinked polymer and composition in order to obtain a hydrogel having excellent mechanical properties, optical properties, and material permeability, and also further improved its polymerization formability. We have discovered a new method that significantly improves this, and have arrived at the present invention.

That is, the present invention cross-links and polymerizes a composition containing N-vinyl lactams, a water-insoluble polymer, a vinyl monomer that gives a water-insoluble polymer when homopolymerized, and N-N'-divinylbislactams as essential components. The present invention provides a method for producing a novel polymer composition in which a crosslinked polymer containing vinyl lactams as a main molecule and a polymer containing a water-insoluble component as a main molecule coexist without macrophase separation. .

By allowing the polymer composition having a crosslinked structure obtained in the present invention to absorb water, a hydrogel with high strength, transparency, and high permeability, which cannot be produced by conventional methods, can be obtained.

In particular, since the method of the present invention provides a method for producing a crosslinked polymer composition with excellent polymerization formability, it is also possible to directly obtain a molded product of hydrogel by performing cast polymerization.

N-vinyl lactams that can be preferably used in the present invention include N-vinylpyrrolidone, N-vinylpiperidone,
-Vinylpyrrolidone, etc., and one or more of them can be used simultaneously.

The other vinyl monomer is a vinyl monomer whose sole polymer is a water-insoluble polymer, and particularly preferred is a vinyl monomer that can be copolymerized with N-vinyl lactams.

Such vinyl monomer groups include acrylic acid or methacrylic acid or their esters, unsaturated nitriles such as acrylonitrinobemethacrylate, aromatic olefins such as styrene, acrylamide, dimethylacrylamide, diethylmethacrylamide diacetone acrylamide. One or two of acrylamide, methacrylamide, or derivatives thereof, such as
More than a species.

In this case, vinyl esters such as vinyl acetate, which can be copolymerized to some extent with both vinyl monomer groups, olefins such as inbutylene, vinyl halides such as vinyl chloride,
Vinyl ether such as vinyl methyl ether can also be added in an amount of about 10% by weight or less of the total weight.

In the present invention, it is desirable that the water-insoluble polymer-forming vinyl monomer is difficult to copolymerize with N-vinyl lactams, but the following criteria can be used in selecting it.

That is, it is desirable that the monomer reactivity ratio (MRR) is 1/r1>1 and 1/r2<1 when N-vinyl lactams are M1 and the other vinyl monomer group is M2.

The water-insoluble polymer used in the present invention is preferably a water-soluble polymer whose main precursor is a vinyl monomer group that is difficult to copolymerize with N-vinyl lactams as described above. Examples of such polymers include polystyrene, polymethyl methacrylate, methyl methacrylate, and methacrylic acid. Copolymers include polymethacrylonitrile, styrene/butadiene copolymer, styrene/acrylonitrile copolymer, vinyl chloride/methyl methacrylate copolymer, polyvinylidene chloride vinyl polymer or copolymer.

These are preferably soluble in N-vinyl lactams or water-insoluble polymer-forming vinyl monomers.

In the present invention, the charging ratio of N-vinyl lactams is
It is preferable that the proportion of the other vinyl monomer group is 15 to 95% by weight of the total, 2 to 50% by weight, and the proportion of the water-insoluble polymer is 1 to 35% by weight, but it is not limited to this range. do not have.

It is also possible to add a solvent to the polymerization stock solution, but in this case it is desirable to use it within a range of 15% by weight or less of the total weight.

The N -N'-divinylbislactams used mainly for crosslinking N-vinyllactams in the present invention are preferably of the general formula [wherein R, , R2 are the same or different, hydrogen or a lower group such as methyl] Represents an alkyl group, m is 0.2 or 4, when m=o or 2, n=2, and when m=4, n
=0 and l is O or 1].

In addition, the multi-sensitivity compounds that are easily copolymerized with the water-insoluble polymer-forming vinyl monomer group used in the present invention include glycerin trimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate, and polyethylene. A known crosslinking agent such as glycol dimethacrylate, bisphenol A bismethacrylate, N-N'-methylenebisacrylamide, trihinyl trinolitate divinylbenzene is added in an amount of 0.01 to 10% based on the vinyl monomer group.
It can be added in a range of mol%.

To further explain the method of the present invention, N-vinyl lactams, water-insoluble polymer-forming vinyl monomers that are difficult to copolymerize with N-vinyl lactams, water-insoluble polymers, N-vinyl lactams,
A composition containing -N'-divinylbislactam as an essential component is mixed into a homogeneous solution state, and a polymerization catalyst, a sensitizer, or both are appropriately added to carry out a polymerization reaction. It is preferable to use radical polymerization.

As the polymerization catalyst or sensitizer, those used in ordinary radical polymerization can be used.

Note that N-N'-divinylbislactam is preferably used in an amount of 0.005 to 5 mol% based on N-vinyllactams.

Now, the biggest problem in direct polymerization is polymerization shrinkage.

For this reason, even if you try to obtain a smooth, uniform, and homogeneous cast surface, or even if you try to obtain a film-like, tube-like, or lens-like molded product in a uniform state, various defects will occur unless you carefully avoid polymerization shrinkage. arise.

The method of the present invention is an attempt to solve this problem, and when producing a crosslinked polymer composition consisting of N-vinyl lactams and a water-insoluble polymer-forming vinyl monomer group, N- - By first cross-linking a group of vinyl monomers that are poorly copolymerizable with vinyl lactams, gelling the whole, and then cross-linking polymerizing N-vinyl lactams, macro phase separation of the resulting composition is avoided. .

Furthermore, we have adopted a method in which a water-insoluble polymer whose main precursor is a vinyl monomer group that is difficult to copolymerize with N-vinyl lactams is present in the system before the start of cross-linking polymerization, and this is fixed during cross-linking polymerization. Efforts are being made to reduce polymerization shrinkage.

A transparent polymer composition without macrophase separation can be obtained from a multi-component polymerization composition as in the present invention, and its transparency can be maintained even in the state of a hydrogel by swelling it with water. This is completely unprecedented and shows how novel the method of the present invention is.

The reason why such polymerization was possible is that N -N/-divinylbislactam is used as a crosslinking agent for N-vinyllactams, and that time-lag crosslinking polymerization of N-vinyllactams and other vinyl monomers is performed. The key to success is that the water-insoluble polymer is immobilized within the crosslinked structure to prevent macrophase separation.

As mentioned in the introduction, the polymer composition obtained by the method of the present invention has excellent mechanical properties, optical properties, material permeability, and polymerization formability. is shown, but is not limited to this.

Example 1 10 parts of polymethyl methacrylate with a molecular weight of about 110,000 prepared by radical polymerization using azobisisobutyronitrile as a catalyst was dissolved in 70 parts of N-vinylpyrrolidone and 20 parts of methyl methacrylate, and N- 0.5 mol % isopropylidene-bis-5-(N-vinylcaprolactam) based on vinylpyrrolidone, 0.05 mol % diethylene glycol dimethacrylate based on methyl methacrylate, and 0.5 mol % based on total vinyl monomers.
2 mol % of azobisisobutyronitrile was added to prepare a stock solution for polymerization.

This stock solution was heated to 60°C for 5 hours on a convex cast mold with a radius of curvature of 5 mm and two surfaces were chrome plated and polished, and then the polymerization temperature was increased to 70°C, 90°C, and 120°C to carry out crosslinking polymerization. I did it.

When the polymer block was removed after polymerization, the concave surface of the cast was extremely smooth, and when a disc piece was cut out from the polymer block and swollen in water, it became a transparent hydrogel with a water content of 72% and a tensile strength of 12 kg and 10 A.

Example 10 Impropylidene) bis- from the polymerization stock solution
When similar polymerization was carried out using threads except for 5-(N-vinylcaprolactam), the resulting hydrogel became cloudy.

In addition, polymethyl methacrylate was removed from the polymerization stock solution in Example 10, and methyl methacrylate was used instead for a total of 30
When the same polymerization was carried out using the same yarn, air bubbles sometimes appeared on the cast surface of the resulting polymer composition.

Example 2 A homogeneous solution was prepared consisting of 5 parts of polystyrene having a molecular weight of about 130,000, 15 parts of N-vinylcaprolactam, 60 parts of N-vinylpyrrolidone, and 20 parts of styrene.
0.5 mol% ethylethene-bis-3-(N-vinylpyrrolidone) based on vinyl lactam, 0.8 mol% bisphenol A bismethacrylate based on styrene, 0.5 mol% azo based on total vinyl monomers. Bisdimethylvaleronitrile, also 0.0% based on total vinyl monomers.
5 mol % of benzoin was added to prepare a polymerization stock solution.

This was poured into a glass container, replaced with argon and then sealed), placed in a constant salt bath at 10°C, photopolymerized for 24 hours using a 450-watt high-pressure mercury lamp, and then heat-treated in an oven at 120°C for 24 hours. Polymerization was completed by

The obtained polymer was transparent and became a transparent hydrogel having a water content of 68% and a tensile strength of 10.5 kg/ca in a horizontally conflicting state.

Claims (1)

[Claims] 1. A method for producing a crosslinked polymer composition, which comprises crosslinking a composition containing N-vinyllactam, a water-insoluble polymer, and a water-insoluble polymer-forming vinyl monomer in the coexistence of N·N'-divinylbislactam. .