JPS606710A - Production of hydrogel molding - Google Patents

Abstract

PURPOSE:To produce a strain-free hydrogel molding in good reproducibility, by polymerizing a mixture of an alkylene glycol mono(meth)acrylate, a polymer prepared from this monomer and other monomers and an organic solvent in a mold. CONSTITUTION:The following mixture is polymerized in a mold having any desired shape: a mixture comprising (A) an alkylene glycol mono(meth)acrylate or a monomer mixture based thereon, (B) a polymer having double bonds in the molecule, prepared from an alkylene glycol mono(meth)acrylate or a mixture thereof with other monomers, and (C) an organic solvent, wherein component B is present in an amount (wt%) higher than that of component A. Although the organic solvents may be any of those which can dissolve components A and B uniformly to form a clear solution, water-soluble organic solvents are particularly preferable because they can be readily removed by extraction during the hydration of the hydrogel molding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for producing a water-insoluble and hydrophilic hydrogel molded article, and the hydrogel molded article is mainly used as a medical material.

[Prior art]

In recent years, the application of polymeric polymers to the medical field has been actively studied. Among them, hydrogels that are insoluble in water and hydrophilic have attracted attention for their permeability to substances (gases, ions, molecules, etc.) and water-retaining properties, and are used in various separation membranes, catheters, soft contact lenses, blood storage containers, and cell culture. It has come to be used as a substrate, blood flow circuit, and embedding material for enzymes, pharmaceuticals, etc.

For this purpose, alkylene glycol mono(meth)acrylate has been widely used.

Many methods for producing hydrogel molded articles using this material have also been proposed. For example, a widely used method for manufacturing lenses is to bulk polymerize monomers to obtain rod-shaped polymers, which are then cut. However, with this method, due to deformation due to moisture absorption of the polymer during processing,
Many difficulties are involved in obtaining soft contact lenses of the same shape with good reproducibility. In order to overcome this problem, for example, Japanese Patent Publication No. 44-26475 proposes α, β-
A mixture of polyhydric alcohol ester of unsaturated motsucarubonic acid and a subtotal (0.1 to 20 parts) of crosslinking agent is used after being diluted with an inert liquid that is easily mixed with water, and a soft contact is made by the double confluence pouring method. Methods of manufacturing lenses, membranes, etc. are described.

However, if only the monomer is diluted with a solvent and used in this way, the polymerization shrinkage associated with the polymerization of the monomer is large.
Therefore, there is a problem that distortion easily occurs in the hydrogel molded product.

[Purpose of the invention]

An object of the present invention is to provide a method for producing distortion-free hydrogel molded articles with good reproducibility.

[Structure of the invention]

That is, the present invention.

A, alkylene glycol mono(meth)acrylate or a monomer mixture mainly composed of alkylene glycol mono(meth)acrylate B, 1 synthesized from a mixture of alkylene glycol mono(meth)acrylate) and other monomers A mixture consisting of a polymer C1 having a polymerizable double bond in the molecule and an organic solvent (I), in which the B component is larger than the A component on a weight basis, is polymerized in a mold having a desired shape. This is a method for producing a hydrogel molded article.

The alkylene glycol mono(meth)acrylate of component A is expressed by the general formula %] However, R is hydrogen or methyl group 2m2゜or 4
．． n is an integer from 1 to Ot, and is a mono(meth)acrylate such as ethylene glycol, diethylene glycol, or tetodiethylene glycol. These can be used alone or as a mixture. In addition, a monomer mixture mainly composed of alkylene glycol mono(meth)acrylate means the above-mentioned alkylene glycol mono(meth)acrylate and one of the following monomers.
It is a mixture of two species or two species.

(1) Hydrophobic monomers (meth)acrylic acid alkyl esters, unsaturated nitriles such as (meth)acrylonitrile, aromatic olefins such as styrene, vinyl compounds such as vinyl chloride, vinyl acetate, etc. (2) Hydrophilic monomers meric alkoxypolyethylene glycol mono(meth)acrylate, N-vinyl lactams such as N-vinylpyrrolidone and N-vinylpiperidone, (meth)acrylic acid, (meth)acrylamide, glycerin mono(meth)acrylate, and the like.

These hydrophobic and hydrophilic monomers are used for the purpose of improving the root properties of the hydrogel and increasing the water content, and the amount used is up to 40% by weight of the component A.

A polymer having polymerizable double bonds in two molecules synthesized from component B alkylene glycol mono(meth)acrylate or a mixture of alkylene glycol mono(meth)acrylate and other monomers is an alkylene glycol. A (co)polymer obtained by (co)polymerizing mono(meth)acrylate or alkylene glycol mono(meth)acrylate with a hydrophobic or hydrophilic monomer described as component A, the (co) It is a (co)polymer obtained by reacting a compound having a functional group that reacts with a hydroxyl group present in the polymer and a polymerizable double bond.

What about functional groups that react with hydroxyl groups?

-GOOR group, C001 group, NGO group, -CH-CH2
Basic＼. / I can give you something. Furthermore, "double hydrophobic."

The proportion of copolymerization between hydrophilic monomers and alkylene glycol mono(meth)acrylates is similar to that of hydrophobic monomers.

Although the amount of hydrophilic monomer may be large, it is necessary to make it less than 40% by weight with respect to the total amount of +Ar & component and B component. -1
The amount of double bonds in a (co)polymer having a polymerizable double bond in one molecule is 1
．． It is preferable that there are about 1 to 40 pieces per DDO. If the amount of double bonds is higher than this, the mechanical properties of the resulting hydrogel.

In particular, the elongation at break is significantly reduced, and if the hydrogel molded product does not contain double bonds, the (co)polymer dissolves into water during water treatment of the hydrogel molded product, making it impossible to obtain a molded product of the desired shape. Note that the amount of double bonds can be determined by Fourier transform NMR or the like.

Regarding the ratio of component A and component B, it is necessary that component B is larger than component A on a 2 weight basis. When the amount of component B is equal to or less than component A.

Polymerization shrinkage increases, and distortion tends to occur in the obtained hydrogel molded product.

The organic solvent for component C may be one that can uniformly dissolve component A and component B and provide a transparent solution, but water-soluble organic solvents are easily extracted and removed during water conservation treatment of hydrogel molded products. Therefore, it can be preferably used. Examples of preferred organic solvents include alcohols such as 1+n-propyl alcohol and cyclohexanol, Nisdels such as ethylene glycol monoacetate, ethylene glycol monomethyl ether, and dimethyl sulfoxide.

Dimethylacetamide, dimethylformamide.

Examples include N-methyl-2-pyrrolidone. The amount of component C used is preferably within a range of 30 to 85 weights based on the total amount of components A, B, and C.

When the amount of solvent is less than this, the viscosity of the mixture becomes very high and handling becomes difficult. Furthermore, if the amount of solvent is too large, the strength of the gel containing the solvent will be weakened, and the gel will be easily damaged.

In the present invention, a crosslinking agent can be used if necessary. The crosslinking agent may be a monomer having two or more polymerizable double bonds in the molecule, and may be any crosslinking agent used in the production of ordinary hydrogels, such as di- or tri-vinyl compounds, allyl compounds, allyl vinyl compounds, etc. is used. The amount of crosslinking agent used is 0.0% for component A.
It is preferable to add 2 to 2 times in a dense manner.

Furthermore, a polymerization initiator can be used if necessary. As a polymerization initiator, 2 azo compounds used in ordinary polymerization,
Peroxide etc. are used.

A stock solution in which the above-mentioned components are uniformly dissolved is poured into a mold, and polymerization is performed by heat, light, radiation, or other means. After the polymerization is completed, the gel formed in the mold is removed from the mold, and at the same time water treatment is performed using pure water or physiological saline.

The solvent and unreacted monomers are extracted, forming a hydrogel molded product.

〔Effect of the invention〕 The effects of the present invention are as follows.

(1) Component B contains more polymers having polymerizable double bonds in its 9 molecules than the monomers of Component A.

In addition, since polymerization is carried out using a polymerization stock solution that also contains a solvent, the polymerization shrinkage rate is reduced, and a hydrogel with no distortion and excellent optical properties is produced. (2) Polymerizable double bonds are formed in the molecules. This occurs when a polymer that does not contain double bonds is used because a polymer that does not contain double bonds is used.'': Una 2
Changes in color of hydrogel molded products due to polymer extraction.

No deterioration of optical properties such as cloudiness occurs.

(3) A hydrogel molded article with excellent mechanical properties, especially elongation at break, can be obtained. This is because the viscosity of the stock solution is higher than when only the monomer and solvent are used because the stock solution in which the polymer is dissolved is used. it is conceivable that.

(4) The use of other monomers in addition to alkylene glycol mono(meth)acrylate.

The mechanical properties can be further improved or the water content can be increased without sacrificing the good optical properties.

[Application range]

The method for producing a hydrogel molded article of the present invention takes advantage of its dual characteristics and can be preferably used for producing soft contact lenses, capsule lenses, and the like.

The present invention will be described in detail below with reference to Examples.

In addition, 2 parts in the examples are parts by weight.

Example 1 1.90 parts of 2-hydroxyethyl methacrylate and 0.09 parts of azobisdimethylvaleronitrile kt "'rN-
The mixture was dissolved in 60 parts of dimethylacetamide, and polymerization was carried out at 50°C for 5 hours, 55°C for 2 hours, and 80°C for 2 hours in a distillate atmosphere. Cool the resulting solution to 20°C.
Then, while stirring this solution, 0.0% methacrylic acid chloride was added.
72 parts were added thereto, and the reaction was carried out for 4 hours using 0.55 part of pyridine as a catalyst.

Next, this solution was poured into 1,4-dioxane to precipitate a polymer of 2-hydroxyethyl methacrylate having two polymerizable double bonds within its molecules.

Removed impurities. The polymerization rate calculated from the weight of the polymer obtained by thorough drying was about 70%, and the polymerization rate was approximately 70%.
The amount of polymerizable double bonds measured by R was about 5 on average per 1000 molecules of 2-hydroxyethyl methacrylate.

Using this polymer, stir and dissolve a mixture with the following composition,
A homogeneous and transparent polymerization stock solution was obtained.

Polymer having a polymerizable double bond in the above molecule 26 parts 2-hydroxyethyl methacrylate 19 parts triethylene glycol dimethacrylate 0.19 parts azobisdimethylvaleronitrile 0.057 parts dimethyl sulfoxide 5811 (This stock solution was It was poured between two glass plates using a polyethylene terephthalate film as a spacer in a nitrogen atmosphere and fixed with a fastener.Then, this was placed in an electric furnace and heated from 40'O to 90'c''z for 6 hours. After polymerization, the resulting film was removed from the glass plate and boiled in a 0.9% NaCl aqueous solution to extract the solvent and unreacted monodisperse. It is hydrated to form a hydrogel film.

The water content was about 40, the breaking strength measured with a Tensilon tensile tester was 8 kg/cn2+, and the elongation at break was 400, which was particularly excellent. The transparency is good, and the transmittance of 1liT visual rays is 95 per 0.1 mm thickness.
91, that's all.

Example 2 Using a polymer of 2-hydroxyethyl methacrylate having a polymerizable double bond in the molecule obtained in the same manner as in Example 1, a transparent polymer stock solution having the following composition was obtained.

26 parts of a polymer having a polymerizable double bond in the molecule 16 parts of 2-hydroxyethyl methacrylate 0.16 parts of trimethylolpropane trimethacrylate 0.016 parts of azobisdimethylvaleronitrile 58 parts of dimethyl sulfoxide This polymerization stock solution was dissolved in a nitrogen atmosphere. After pouring into a mold to form the shape of a contact lens, it was heated in an electric furnace for 40 minutes.
'a to 85°Cj for 5 hours to polymerize 'f: h
became. After the polymerization was completed, the lens was removed from the mold and hydrated by boiling in physiological saline, and the solvent and residual monomers were extracted. The obtained lens was transparent, and when the resolution was measured using a lens meter manufactured by Nippon Kogaku Co., Ltd., the projected pattern image was clear and no distortion was observed.

Example 6 50 parts of methyl methacrylate, 50 parts of 2-hydroxyethyl methacrylate, and 5 parts of methacrylic acid were dissolved in 700 parts of 1,4-dioxane, 042 parts of azobisdimethylvaleronitrile was added, and 50 parts of methacrylic acid was dissolved in a nitrogen atmosphere. Q: Polymerization was carried out for 8 hours. After polymerization, methacrylic acid chloride 0
9 parts were added, and a reaction was carried out using pyridine as a catalyst.

Next, this solution was poured into water to precipitate and collect a copolymer having polymerizable double bonds in 8 molecules, which was then dried.

Using this copolymer, we obtained a uniform and transparent polymer stock solution with the following composition.

Copolymer 257 having a polymerizable double bond in the above molecule
Part 2-Hydroxyethyl methacrylate 18 parts Methacrylic acid 018 parts Trimethylolpropane trimethacrylate 0.18 parts Azobisdimethylvaleroni l-') 0.018 parts Dimethyl sulfoxide 65.8 parts This polymerization stock solution was applied to the shape of a contact lens. Injected in a nitrogen atmosphere into a mold to form a
The temperature was then increased to 85℃ over 4 hours.

Polymerization was carried out. After the polymerization was completed, the lenses were removed from the molds and boiled in physiological saline to carry out water treatment and extraction of solvents and unreacted monomers. The water content of the obtained lens is approximately 5
6, and the breaking strength is approximately 17 kg/cm2. ' The elongation at break was approximately 260 modulus. It also had good transparency, and no optical defects were observed even when observed with a 10x magnifying glass.

Example 4 Using a polymer of 2-hydroxyethyl methacrylate having a polymerizable double bond in the molecule obtained in the same manner as in Example 1, a uniform and transparent polymer stock solution having the following composition was obtained. .

Polymer of 2-hydroxyethyl methacrylate having a polymerizable double bond in the molecule 20 parts Methyl methacrylate 88 parts Methacrylic acid 11 parts Trimethylolpropane trimethacrylate 015 parts Azobisdimethylvaleronitrile 0.025 parts Dimethyl sulfoxide 80 parts This polymerization stock solution was placed between glass plates in the same manner as in Example 1, and polymerized in an electric furnace at 95'Q-d from 40°C for 5 hours. A transparent hydrogel film was obtained by processing and extracting the solvent and unreacted monomer. The moisture content is about 50%, and the breaking strength is about 17 bags/river 2. The elongation at break was about 400%, indicating good mechanical properties.

Patent applicant Higashi Shikikai Co., Ltd.

Claims (1)

[Scope of Claims] A, alkylene glycol mono(meth)acrylate or a monomer mixture mainly composed of alkylene glycol mono(meth)acrylate B, alkylene glycol mono(meth)acrylate or alkylene glycol mono(meth)acrylate A method for producing a hydrogel molded article, which comprises polymerizing a mixture consisting of a solvent and in which component B is greater than component A on a weight basis in a mold having a desired shape.