JPH01263106A - Novel crosslinked copolymer, gel thereof and structure thereof - Google Patents

Abstract

PURPOSE:To obtain a novel copolymer consisting of a unit of an alkali metal of sulfoalkyI methacrylate, a unit of 2-hydroxyalkyl methacrylate and a unit of polyethylene glycol dimethacrylate. CONSTITUTION:A novel crosslinked copolymer consisting of 10-80wt.% unit of an alkali metal of sulfoalkyl methacrylate shown by formula I (R1 is -CH2CH2- or -CH2CH2CH2-; M is Na or K), 20-90wt.% unit of 2-hydroxyalkyl methacrylate shown by formula II (R2 is -CH2CH2- or -CH2C(CH3)H-) and 0.25-5wt.% unit of polyethylene glycol dimethacrylate shown by formula III [R3 is -(CH2-CH2O)n-(n is 0-22)]. The copolymer can be blended with water and 1-6C polyhydric alcohol to give gel having high transparency, the gel is reinforced with nonwoven fabric or woven fabric or laminated to a film, etc., to give a laminate and is useful as an electrode for electrocardiograph or a hydrous patch such as fomentation.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention is applicable to adhesive adhesives for electrocardiographs, adhesive electrodes for low-frequency treatment devices, ultrasound transmission media for ultrasound diagnosis, and water-containing adhesive patches such as poultices. This invention relates to a new crosslinked copolymer, its gel, and its tub body.

(Prior art) Conventionally, as a biomedical electrode, a method using natural water-soluble polymers such as gelatin has been known (Japanese Patent Publication No. 50-2
No. 7317), and as a method using a synthetic polymer, a hydrophilic polymer containing at least 5 mol% of monomer units containing a salt of a carboxylic acid is used (Japanese Patent Laid-Open No. 56
-36939), an electrode material obtained by polymerizing a precursor consisting of a water-soluble polyhydric alcohol, an ionic unsaturated material, a polyfunctional unsaturated material, and a free radical initiator on an electrode plate No. 500003) etc. are also known. Furthermore, the present inventors have discovered that an ionic unsaturated monomer, a trialkoxyalkyl (meth)acrylate, a polyalkylene glycol (meth)acrylate, and a water-soluble polyhydric alcohol are polymerized and crosslinked in the presence of water. The company has discovered that the conductive adhesive is excellent for biomedical electrodes, and has already filed an application. (Unexamined Japanese Patent Publication No. 61-268767) (Problems to be Solved by the Invention) However, when using natural water-soluble polymers, the quality is not stable because they are natural products, and the quality is unstable due to contamination and impurities. Deterioration etc. will occur.

On the other hand, when synthetic polymers are used, they do not have the above drawbacks. However, in conventional technology, polyhydric alcohols such as glycerin are often used for moisturizing purposes, and the presence of these polyhydric alcohols provides a suitable place for mold to grow. This is a problem not only for natural polymers but also for synthetic polymers, and there is a need to use antifungal agents. In addition, in the case of copolymers of polyacrylic acid and polyacrylate salts, which have been mainly used in the past, there is a problem that physical properties such as water absorption and cohesiveness change depending on the pH of the system. If an attempt is made to include the copolymer, there are problems in that the properties change depending on the drug, or that the copolymer and the drug react or interact. Also, JP-A No. 61-26876
There are cases where No. 7 mold does not develop, but the stickiness may change over a long period of time.

(Means for Solving the Problems) The present invention has excellent water retention, cohesion, and antibacterial properties, and has P H
The purpose of the present invention is to provide a new crosslinked copolymer that is hydrophilic and has a water content and solubility that are not affected by water, and also to provide a gel made of this new crosslinked copolymer and a gel containing the same.

The above object of the present invention is to CH.

The alkaline value of sulfoalkyl methacrylate represented by the formula +CH2-C) is C=0. ■ So, M 10 to 80% by weight of metal salt units (hereinafter abbreviated as A units), CH.

2-Hydroxyalkyl MEC of the formula +CHx C+ 1. Ru 1~C=0 01-■ m position (hereinafter abbreviated as B unit) 20-90% by weight and polyethylene glycol dimethacrylate-1 bleached R1 represented by CH3 (CH2-C) formula) C=O 1+CH, -C-)- glance CH.

The new bridge consisting of 0.2 to 5% by weight of C units (hereinafter abbreviated as C units) is a copolymer (R1 is 10H, -CH2
- or -CH2-CH2-CH,-, R2 is 10) (2CH2- or CH2-CH-, and R3 is CH.

-(CH2-C)-720+, CH2-CH,-(n=
o ~22), and M is Na or K. ), and is determined by a gel consisting of the above-mentioned new crosslinked copolymer, water, and a polyhydric alcohol with a carbon number of 6 or less, and a structure in which the gel is reinforced with a nonwoven fabric or laminated with a film, etc. achieved.

(Function) The present invention relates to a novel crosslinked copolymer consisting of A units, B units, and C units. These structural units will be explained below.

First, the sulfoalkyl methacrylate in the A unit is
It is a compound having a structure in which the sulfonic acid group of a methacrylic ester of an aliphatic alcohol having a sulfonic acid group is neutralized with an alkali, and sodium salt or potassium salt of 2-sulfoethyl methacrylate or 3-sulfoalkyl methacrylate is preferably used. . These monomers are salts of strong acids and strong bases, and because they have a neutralized structure, they have strong hydrophilic properties and are less likely to interact with pond additives and drugs. In addition, it has a moderately long alkyl group, so it can be used as a salt.
It is estimated that the glass transition temperature is not very high, giving the polymer relatively flexible properties. B units have traditionally been used as raw materials for water-insoluble, hydrophilic copolymers;
In the present invention, the above-mentioned sulfoalkyl methacrylate is copolymerized for the purpose of further enhancing hydrophilicity.

Further, as the C unit, there are ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate (n = 9.14.23 etc.), all of which are preferably used. If the vine used is tetraethylene glycol dimethacrylate, a particularly pleasant texture can be obtained. It is desirable to adjust the proportions of each component in the crosslinked copolymer of the present invention appropriately depending on the purpose of use, but the A unit is 10 to 80% by weight of the total monomer, and the B unit is 20 to 80% by weight.
90% by weight, and the C unit is appropriately determined in the range of 0.2 to 5% by weight. The crosslinked copolymer of the present invention can be particularly usefully used as a gel containing water and a polyhydric alcohol having 6 or less carbon atoms.

In the present invention, examples of polyhydric alcohols having 6 or less carbon atoms include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, diethylene glycol, glycerin, diglycerin,
2,3-butanediol, 1,2-butanediol, 1
．． Examples include 3-butanediol, 3-methyl 1,3-butanediol, 3-methyl 1,3,5-pentanediol, and the like.

The blending ratio of the crosslinked copolymer, water, and glycerin in the gel of the present invention must be appropriately determined depending on the desired physical properties (e.g., flexibility, adhesiveness, electrical conductivity, etc.); is 20-40% by weight of the gel, preferably 25-35% by weight, water is 5-50% by weight, preferably 15-40% by weight, and polyhydric alcohol is 25-70% by weight.
% by weight, preferably from 30 to 60% by weight.

Depending on the composition and form of the copolymer, the gel of the present invention has physical properties that are suitable for use as a gel alone, but depending on the composition and form, the gel may have strong stickiness, or may have good form stability, such as those that are flexible and thin. Sometimes there isn't. In such cases, in order to improve the morphological stability, reinforcing materials such as non-woven fabrics, woven fabrics, or lil materials may be added to the gel to make it into a sheet-like product, or sheet-like materials such as films or cloth may be used. By laminating it with a material, it can be used in practical applications (it can be rubbed).The gel, structure, etc. may be mixed with electrolytes such as salt, coloring agents such as dyes and pigments, and drugs such as analgesics as necessary. Good too.

The crosslinked copolymer of the present invention can be obtained by polymerizing constituent monomers. Since the crosslinked copolymer of the present invention is insoluble in various solvents, it can be polymerized in a solvent that dissolves the monomers to obtain a gel-like product, and then the solvent can be removed by extraction or heating. You can let go. Since the monomers of the present invention undergo radical polymerization easily, a method of heating in the presence of a thermal polymerization catalyst such as azobisisobutyronitrile, benzoyl peroxide, lauroyl peroxide, etc., a method of heating in the presence of a thermal polymerization catalyst such as azobisisobutyronitrile, benzoyl peroxide, lauroyl peroxide, etc. Usual radical polymerization techniques can be used, such as a method of irradiating ultraviolet rays in the presence of a photopolymerization initiator such as hexylphenylgetone, or a method of using both in combination. The gel, which is an important form of the present invention, can also be obtained by swelling the crosslinked copolymer isolated as described above with a mixture of water and polyhydric alcohol, but the monomer constituting the crosslinked copolymer A gel of a desired shape can be obtained by placing a mixture of a polyhydric alcohol having 6 or less carbon atoms and water in a container of a desired shape and polymerizing the mixture. According to such a method, in addition to the advantage that a gel can be obtained in one step, the polymerization proceeds while the system is homogeneous from the beginning, so that a gel having a transparent and beautiful appearance can be obtained.

In addition, to obtain a laminate with a sheet-like material, film, cloth, etc. containing a reinforcing agent, a mixture of raw material monomers, water, polyhydric alcohol, etc. and nonwoven fabric, woven fabric, knitted fabric, film, cloth, etc. are prepared in the desired form. The desired structure can be easily obtained by polymerizing the structure.

[Firepower color example]

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 5 parts by weight of potassium salt of 3-sulfopropyl methacrylate (hereinafter abbreviated as SPM) was dissolved in 15 parts by weight of water to obtain a uniform aqueous solution. 1-Hydroxycyclohexylphenylgetone (trade name Irgacure 184>0.1
A solution of 25 parts by weight and 0.2 parts by weight of tetratactic ethylene glycol dimethacrylate in 35 parts of 2-hydroxypropyl methacrylate was further mixed with 44.7 parts of propylene glycol. This mixed solution was added to the SP
A monomer mixture was obtained by mixing with an aqueous solution of M. This monomer mixture was poured into a silicone resin mold having a recess of 10 cm in length, 20 cm in width, and 3 cm in depth.
3cm) gemical rung (F L 30 manufactured by Toshiba)
It was placed at a position 15 ae below S B L'), and after the whole was replaced with nitrogen, it was irradiated with ultraviolet rays for 10 minutes. Upon release from the silicone resin mold, a transparent hydrogel with rubber-like elasticity and almost no surface tackiness was obtained. When this product was applied to a person's neck or abdomen, it fit the skin well. When the ultrasound probe was applied from above the hydrous gel, we were able to obtain good ultrasound images.

Example 2 15 parts by weight of SPM was dissolved in 17.5 parts by weight of water, and SP
An aqueous solution of M was prepared. 0.1 parts by weight of 1-hydroxycyclohexyl phenyl ketone and 0.1 parts by weight of tetraethylene glycol dimethacrylate (7-i) were dissolved in 15 parts by weight of 2-hydroxyethyl methacrylate, and this solution was mixed with the SPM aqueous solution. . This mixed solution was placed in a petri dish placed horizontally so as to have a thickness of 1/4 inch, and polymerization was carried out in the same manner as in Example 1 to obtain a hydrogel. This gel was heated in an oven at 80°C for 3
After drying for several days, a glassy polymer was obtained.

When this was soaked in water, it only swelled and did not dissolve. From this, it is clear that this polymer is a crosslinked copolymer. In addition, this polymer can be crushed into KB
When an infrared spectrum was taken using the gamma tablet method, the spectrum shown in Figure 1 was obtained. That is 3400CI+-
The absorption of ) fE ' indicates the presence of <OH based on MA;
The broad absorption around 1150c+-' is based on SPM (SO
It shows the existence of i.

Example 3 15.2 parts by weight of SPM and 0.8 parts by weight of common salt.
A SPM aqueous solution was prepared by dissolving in 4 parts by weight of water. 8. 20.1 parts by weight of 1-hydroxycyclohexylphenyl keto and 0.4 parts by weight of tetraethylene glycol dimethacrylate were added to 2-hydroxyethyl methacrylate with an ethylene glycol dimethacrylate content of 0.3%.
It was dissolved in 8 parts of Li and further mixed with 52.6 parts of glycerin. This mixed solution was mixed with the above SPM aqueous solution to form a monomer mixture. A polyester film whose surface had been siliconized was placed on a glass plate held horizontally. On top of this, 3 c of rayon nonwoven fabric with a basis weight of 1Qg/nf
x h When ultraviolet rays were irradiated for 7 minutes in a N2 atmosphere in the same manner as in Example 1, a sticky, soft, and morphologically stable hydrogel was obtained. When this material was peeled off from the film, attached to an electrode plate made of conductive rubber with an electrical cord attached, and applied to the skin, it was able to be held properly on the skin due to the adhesive strength of the hydrogel. When the cord was brought into contact with a low-frequency treatment device and electricity was applied to it, it was found to have good conductivity. This gel was used for about 10 minutes once a day for one week and was left hanging indoors for three months, but no mold growth was observed. In addition, although there was a decrease in tackiness due to sewage and dirt during use, no change in physical properties was observed when left unused.

Example 4 A SPM aqueous solution was prepared by dissolving 15 parts by weight of SPM and 0.8 parts by weight of common salt in 17.5 parts by weight of water. 0.1 part by weight of 1-droxycyclohexyl phenylgetone, 0.4 part by weight of tetraethylene glycol dimethacrylate,
0.42 parts by weight of fluorescent dye Fluorescent Orange,
0.1 parts by weight of ethylene glycol dimethacrylate and 15 parts by weight of 2-droxyethyl methacrylate were mixed with 52.5 parts by weight of glycerin. This liquid mixture was mixed with the SPM aqueous solution to form a monomer mixture. A polyester film whose surface had not been siliconized was placed on a glass plate held horizontally. Place gauze on top of this 3 x 5 cm
2.6 g of the monomer was dropped onto it, and the liquid was spread into a gauze shape. When ultraviolet rays were irradiated for 7 minutes in a N2 atmosphere in the same manner as in Example 1, a sticky, fluorescent, pinkish-orange hydrogel was obtained. Since this product was colored, it had a beautiful appearance, and like Example 3, it had excellent performance as a low-frequency treatment device, and no mold was observed.

Example 5 Sodium salt of 2-sulfoethyl methacrylate (hereinafter abbreviated as SEM) was dissolved in 37.5 parts by weight of water, and SE
An aqueous solution of M was obtained. 0.1 parts by weight of 1-human 0-oxycyclohexyl phenyl getone, 5 parts by weight of polyethylene glycol dimethacrylate (n=23), 1 part by weight of methyl salicylate
Parts by weight, 2-hydroxyethyl methacrylate 17,5
parts by weight and 0.0 parts by weight of ethylene glycol dimethacrylate.
08 parts by weight were mixed to form a homogeneous solution, and further mixed with diglycerin. This solution was uniformly mixed with the SEM aqueous solution to obtain a monomer mixture. A 25 μm thick polynisdel film was placed horizontally and coated with the monomer mixture using a bar coater to a thickness of 150 μm.

When exposed to ultraviolet rays for 7 minutes in a N4 atmosphere in the same manner as in Example 1, a laminate of a transparent and sticky film and a hydrous gel was obtained. The gel layer was extracted with methanol and analyzed by gas chromatography. As a result, it was found that the amount of methyl salicylate contained was the same as the amount charged.

Example 6 In Example 3, a small amount of sulfuric acid was added to the SPM aqueous solution, and S
The pH of the PM aqueous solution was lowered to 2. A hydrogel was obtained in the same manner as in Example 3 using this SPM. The adhesiveness and aggregation properties of this gel were similar to those of the gel of Example 3, and no mold growth was observed.This gel was pasted on two stainless steel flat plates each measuring 60 boxes in length and width. The two stainless steel plates were connected to the measuring gauge of F Impedance Analyzer 4192A (manufactured by Yokogawa Hewlett-Baccard) and the impedance was measured at a frequency of IQHz. It was 97.2Ω (phase angle 59°).On the other hand, when similar measurements were made using the gel of Example 3, it was 186Ω.
．． By lowering the pH, which was 3Ω (phase angle 63.4°), the conductivity could be changed without changing almost any other physical properties.

(Effects of the Invention) According to the present invention, it is possible to obtain a hydrophilic and water-insoluble crosslinked copolymer that is stable in quality, has excellent mold resistance and stability over time, and shows little change in physical properties due to PH. Furthermore, it is possible to obtain a hydrogel using this crosslinked copolymer and a structure using the hydrogel.

[Brief explanation of the drawing]

FIG. 1 shows an infrared spectrum of the novel crosslinked copolymer of the present invention obtained in Example 2.

Claims (4)

[Claims] (1) Alkali metal salt unit of sulfoalkyl methacrylate represented by formula ▲ Numerical formula, chemical formula, table, etc. ▼
0 to 80% by weight, 2-hydroxyalkyl methacrylate units represented by the formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ 20 to 90% by weight
and a new crosslinked copolymer consisting of 0.2 to 5% by weight of polyethylene glycol dimethacrylate units represented by the formula ▲ (numerical formula, chemical formula, table, etc.). (However, R_1 is -CH_2-CH_2- or -C
H_2-CH_2-CH_2-, R_2 is -CH_2-CH_- or ▲ mathematical formula, chemical formula,
There are tables, etc. ▼, and R_3 is M is Na or K. ) (2) A gel comprising the novel crosslinked copolymer described in claim 1, water, and a polyhydric alcohol having 6 or less carbon atoms. (3) A homogeneously mixed highly transparent gel according to claim 2. (4) A gel structure obtained by reinforcing the gel described in claim 2 with nonwoven fabric, woven fabric, knitted fabric, etc., or laminating it with a film body, conductive material, etc.