CS263644B1 - Copolymers of acrylic or methacrylic acid or alkalic metal salts thereof - Google Patents

Abstract

The solution pertains to copolymers of acrylic acid or methacrylic acid or their alkaline metal salts with macromonomers based on oligourethanes terminated with an unsaturated group of acrylate and/or methacrylate type at one or both ends of the chain, the chemical structure of which corresponds to the general formula I <IMAGE> or general formula II <IMAGE> where R is the residue of a low-molecular-weight aliphatic diol with 2 to 4 carbon atoms, R' is the residue of an aliphatic aromatic, or aliphatic-aromatic diisocyanate, X is H or CH3, and n = 2-40, whereas their composition is given by the ratio of 0.5 to 10 wt. parts of the macromonomer to 100 wt. parts of acrylic acid or methacrylic acid or their alkaline metal salts. The above described copolymers have the capacity to absorb large amounts of water and therefore are suitable as materials removing water, above all for medical purposes, and for applications in the form of a gel in swollen state.

Description

The present invention relates to copolymers of acrylic or methacrylic acid or their alkali metal salts with macromonomers based on oligourethanes, which copolymers are capable of absorbing large amounts of water and are therefore suitable as water-removing materials or for use in the swollen gel form.

Until now, mainly natural materials such as non-woven cellulose or cotton non-woven fibers, natural or synthetic spongy materials used for the production of various medical articles, diapers, 2-tapes, etc. have been applied as water-absorbing materials. however, they are far from meeting the requirements regarding the ability to absorb sufficient amounts of water or other bodily fluids.

Therefore, materials based on water-soluble polymers or copolymers have recently been proposed for this purpose, the solubility of which is virtually eliminated by cross-linking with cross-linking agents, which are compounds containing two or more functional groups capable of reacting (e.g., unsaturated bonds, epoxy etc.). ). Another way to reduce solubility is to partially replace hydrophilic groups with lipophilic groups.

Such materials have been obtained, for example, by copolymerization of acrylic acid with ethylene glycol dimethacrylate or methacrylic acid with divinylbenzene (cf. АО 185 863 from 1978), arolamide with Ν, Ν'-alkylidenebisacrylamide (АО 219 835 from 1986) and further ethylene glycoldiacrylate and Jinyl No. 6,823,468), by crosslinking N-hydroxyacrylamide using light energy at low temperatures (Jpn. 6,931,823), copolymerizing polyolmethacrylate with unsaturated acids or basic group-containing monomers in the presence of ethylene glycol diacrylate, methylenebisacrylamide or divinylbenzene 325. 749), optionally by copolymerization of unsaturated carboxylic acids or sulfoacids with polyalkylene diacrylate or polyethylene glycol diglycidyl ether (GB. 2,081,725 of 1982).

It is further known to prepare a copolymer of ethylene, a vinyl ester such as vinyl acetate and an acrylic ester such as methyl ester with divinylbenzene, which is subsequently saponified (Jpn. 78 104 691). Acrylonitrile-grafted polysaccharides (starches, cellulose, and the like) also provide, after saponification, products with considerable water-absorbing capacity (U.S. Pat. No. 3,661,815 and U.S. Pat. No. 3,669,103). Similarly, the acrylic or methacrylic acid grafted polysaccharides formed by direct copolymerization are materials with similar properties (Jpn. 8 238 809) as well as materials formed by modifying polyvinyl alcohol with the sodium salt of acrylic or methacrylic acid (DE 2 935 712 from 1980). '

However, the above-mentioned materials have shown a number of problems in practical use, the main of which was the lack of water or body fluid absorption, and some of their preparation processes are very complicated. If some were then used for a long time in the swollen state, ie in the form of a gel, their structure was destroyed due to low stability.

The object of the invention, which removes the described drawbacks, is a copolymer of acrylic or methacrylic acid or their alkali metal salts and macromonomers based on oligourethanes terminated at one or both ends by an unsaturated bond of the acrylate or methacrylate type or mixtures thereof whose chemical structure is represented by the general formula I x

h [oR-OCONHR'.NHCo] _n OCH ₂ CH ₂ OCO-C = CH ₂ (I) or formula II

X

CH ₂ = C-COOCH ₂ CH ₂ OCONHR ~ .NHCo [oR-OCONHR'.NHCoJ

I _n OCH ₂ CH ₃ OCO-C = CH ₂ (II) wherein R represents a residue of a low molecular weight aliphatic diol having 2 to 4 carbon atoms, R 'represents a residue of an aliphatic, aromatic, or aliphatic-aromatic diisocyanate, X is H or CH 2 = 2 to 40, the composition of which is given by a ratio of from 0.5 to 10 parts by weight, parts by weight of macromonomer per 100 parts by weight, parts by weight of acrylic or methacrylic acid and their alkali metal salts, respectively.

Suitable diisocyanates are aliphatic hexamethylenediisocyanate, aromatic p-phenylenediisocyanate, 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate (or a mixture thereof), m-xylylenediisocyanate, 1,5-naphthalenediisocyanate and aliphatic-4,4'-diisocyanate. bis (phenylisocyanate) and 4,4'-ethylene-bis (phenylisocyanate). Difunctional oligourethane is formed by a polyaddition reaction in the presence of low molecular weight diols such as ethylene glycol, propylene glycol, 1,2-propanediol,

1,4-butanediol and diethylene glycol (3-oxa-1,5-pentanediol).

Oligourethane with one or two terminal vinyl groups is prepared either sequentially, i.e. first, the diisocyanate is first reacted with hydroxyacrylate and / or hydroxyacrylate. methacrylate and after completion of the reaction, the addition is carried out with the appropriate diol. The reaction can also be carried out in a single step, in which both the hydroxy compounds, monohydroxy and dihydroxy, react simultaneously with the diisocyanate. In both the first and second cases, the hydroxyalkyl ester functions as a terminator.

The preparation of these oligourethane-based macromonomers terminated at one or both ends of the molecules with an unsaturated double bond of the acrylate or methacrylate type is described in U.S. Pat. АО 223 409 (1983) and GB Pat. 2,099,437 (1984).

The ability to absorb water or body fluids and, indirectly, the mechanical strength of the gels in the swollen state is dependent on the ratio of the two components of the copolymer. According to the claims for one or the other, a ratio of macromonomer of up to 0.5 to 10% by weight, parts per 100 parts of acrylic or methacrylic acid or their alkali metal salts, i.e. sodium or potassium, is chosen.

The actual copolymerization reaction can be carried out by any generally known method using initiators of non-initiating systems leading to free-radical copolymerization, such as dibenzoyl peroxide, cumene hydroperoxide, cyclohexanol peroxide, diacetyl peroxide, di-tert-butyl peroxide, diisopropyl percarbonate, azo-bis-isobutyronitrile, ammonium and their possible combination with reducing agents such as thiosulfate

2+ + sodium, ascorbic acid, hydroxyacetone, and metal ions such as Fe or Cu. The reactions may be carried out either in the absence or in the presence of a solvent (in a block), i.e. in water, alcohols, ketones, or aprotic solvents such as dimethylformamide or N-methylpyrrolidone, optionally mixed with water.

As previously shown, the copolymerization of commercial low molecular weight monomers of 2-hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, N-vinylpyrrolidone - with an oligourethane-type macromonomer conditional upon the relatively high mechanical strength of the resulting products in the swollen state of the MS. АО 250 939. This phenomenon has also been shown to occur in the case of copolymerization of acrylic or methacrylic acid or their alkali metal salts, which, even when swollen, have distilled water per 10 000 to 35 000 of the original mass, i.e. at a content of 1 to 0.286 % solids good mechanical strength.

The swelling determination of these highly swellable materials was carried out by placing 0.5 g of crushed (ground) copolymer in a 250 ml graduated cylinder and pouring it into distilled water until the cylinder was filled. By deducting the gel volume in the cylinder after 24 hours of standing, the swelling was determined by dividing the obtained value by 0.5 or multiplying by 2, respectively. If we multiply the result by 100, we get the final result in%.

As follows from the present description and from other examples, the process for the preparation of these copolymers is easy and does not differ from the usual processes.

Example 1

Preparation of oligourethane (macromonomer) with a molecular weight of 2,300 (according to MS АО 223 409).

In a 1000 ml glass kettle equipped with a jacket connected to a thermostat, a reflux condenser with a chloro-calcium cap, a nitrogen inlet and a thermometer was placed 82.4 ml hexamethylenediisocyanate (NCO content: 98.3% th.), 9.15 ml, 2-hydroxyethyl methacrylate and 1.5 g of tetrabutyltin. After 2 hours at 50 ° C, with stirring and in an N-atmosphere, 300 ml of dimethylformamide was added, followed by homogenization of 53 g of 2,2-oxy (diethanol), (diethylene glycol) dissolved in 300 ml of dimethylformamide in the presence of 4.5. ml tetrabutyltin. Allowed to react for another 6 hours. The product was then precipitated by pouring the reaction mixture into 8 L of distilled water with stirring, leaving the precipitate in water overnight at normal temperature. The filtered precipitate was washed with water and dried under vacuum to constant weight.

108 g of dry powder product were obtained, the average molecular weight of which was determined from the content of terminal double bonds (11 mol%) by NMR.

Example 2

To a 100 ml Erlenmeyer flask was added 50 g of freshly pre-distilled acrylic acid, 2.5 g of macromonomer based on 2300 molecular weight oligourethane and containing 11 mol% of the double bonds prepared according to Example 1 and 50 mg of azobisisobutyronitrile was added. After thorough mixing on an electromagnetic stirrer, the mixture was divided into 8 10 ml ampoules, which were first purged with nitrogen, and after melting the copolymerization reaction was carried out in two steps: first 20 hours at room temperature (the main reaction took about 3 hours), then 16 hours at 40 ° C. After removal from the ampoules, the product was ground on a cross mill and poured over 12,500 ml of 0.05 M sodium hydroxide (NaOH). After 24 hours, the liquid over the swollen gel was decanted and washed twice with 10,000 ml of distilled water. After the last decantation of the water (pH 6.5), 500 ml of ethanol was added resulting in substantial gel swelling while maintaining a granular structure. This was filtered and dried in a vacuum oven at 40 ° C. The powdered product was swelled to 210 ml with 1 g of distilled water.

Example 3

Preparation of an oligourethane (macromonomer) based on diphenylmethane diisocyanate of M @ 2 = 2800.

60 g of 4,4-methylenebis (phenylisocyanate) (MDI), 440 g of dimethylformamide and 4.68 g of 2-hydroxyethyl methacrylate (HEMA) were weighed into the glass kettle described in Example 1. The mixture was warmed to -50 ° C under nitrogen and held at that temperature for 2 hours. A mixture of 15.26 g diethylene glycol (DEG) and 8.47 g 1,4-butanediol (BD) was then added. Continue the reaction for a further 4 hours.

Used molar ratio of starting components:

MDI: HEMA: DEG: BD = 1.0: 0.15: 0.6: 0.4

After completion of the reaction, the reaction mixture was cooled to room temperature and the product precipitated with vigorous stirring in 10 L of distilled water and worked up analogously to Example 1. After drying, 86 g (98% of theory) of a macromonomer powder with M &gt; ⁿ by the end-group method (H-NMR).

Example 1 a d 4

Into a glass flask equipped with a stirrer, nitrogen inlet and thermometer was charged 10 g of freshly distilled acrylic acid, 50 ml of 3 M aqueous sodium hydroxide (NaOH) and

0.02 g of macromonomer o = 2870 (see Example 3). After the reaction mixture was stirred and purged with nitrogen, 0.25 ml (NH ₄ ) ₂ S ₂ 0g was added as a 1% aq.

0.25 ml of a 6% aqueous solution of triethanolamine. While stirring, the temperature was raised to 40 ° C and held for 6 hours. The reaction product was washed with 50% aqueous ethanol and dried under reduced pressure at 50 ° C for 24 hours. The absorption of distilled water was 31,000%.

Claims (1)

Copolymers of acrylic or methacrylic acid or their alkali metal salts and macromonomers based on oligourethanes terminated at one or both ends by an unsaturated bond of the acrylate or methacrylate type, or mixtures thereof, whose chemical structure is represented by the general formula I X h-o-R-OCONHR'NHCo _n OCH ₂ CH ₂ OCO-C = CH ₂ (I) or formula II XX •. - ¹ CH ₂ = C-COOCH ₂ CH ₂ OCONHR.NHCO 1 R -OCONHR.NHCO 1 _n OCH ₂ CH ₃ OCO-C-CH ₂ (II) wherein R represents the remainder of a low molecular weight aliphatic diol having 2 to 4 carbon atoms, R 1 represents a residue of an aliphatic, aromatic or aliphatic-aromatic diisocyanate, X is H or CH 3 and n = 2 to 40, the composition of which is given by a ratio of 0.5 to 10 parts by weight, parts by weight of macromonomer per 100 parts by weight or methacrylic or their alkali metal salts, respectively.