CA1078733A - Bandages containing polyurethane urea gels - Google Patents
Bandages containing polyurethane urea gelsInfo
- Publication number
- CA1078733A CA1078733A CA258,926A CA258926A CA1078733A CA 1078733 A CA1078733 A CA 1078733A CA 258926 A CA258926 A CA 258926A CA 1078733 A CA1078733 A CA 1078733A
- Authority
- CA
- Canada
- Prior art keywords
- gel
- weight
- water
- isocyanate
- bandage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
- A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
- A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
- A61L15/26—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof
Abstract
ABSTRACT OF THE DISCLOSURE
This invention relates to the manufacture of novel bandages which are based on stable polyurethane urea gels.
The gels are prepared from NCO prepolymers, which are obtained from polyethers which contain at least 40% of ethylene oxide units, and chain extending agents such as water and/or poly-amines. The gels may be prepared with perfumes, pharmaceutical preparations and other additives. The bandage is optionally made with supporting, intermediate and/or covering layers.
This invention relates to the manufacture of novel bandages which are based on stable polyurethane urea gels.
The gels are prepared from NCO prepolymers, which are obtained from polyethers which contain at least 40% of ethylene oxide units, and chain extending agents such as water and/or poly-amines. The gels may be prepared with perfumes, pharmaceutical preparations and other additives. The bandage is optionally made with supporting, intermediate and/or covering layers.
Description
This invention relates to bandages and their pre-paration.
Bandages according to the present state of the art consist of woven or knitted materials which may also be com-bined with plastic sheets. Both natural and synthetic fibers may be used for the manufacture of the woven or knitted ;
fabrics. Bandages which are required to have a cooling effect for the treatment of inflammatory swellings are usually dipped in water, but such swellings may also be treated with wet towels, handkerchiefs or other woven or knitted materials inqtead of bandages. The same method of treatment is also used for reducing high body temperatures, for example, in infants and small children. -In that case, wet towels or handkerchiefs are wrapped around the patient's calves. This procedure has numerous disadvantages. The main disadvantage is that textile materials of the above-mentioned type may only hold a very limited quantity of water and any excess would drip from the bandage and wet the surrounding areas.
It has now been found that the disadvantages of the bandages previouqly used may be overcome by using bandages made of materials based on polyurethane urea gels~
The materials used according to the present invention may consist of the gels alone or they may advantageously consist of combinations of the gels with any supporting layers of textile or non-textile products. These supporting layers may be bonded to the polyurethane on one or both sides.
The hydrogels and alcohol gels to be used according to the present invention, which are based on polyurethane polyureas, have been essentially disclosed in German DOS
Bandages according to the present state of the art consist of woven or knitted materials which may also be com-bined with plastic sheets. Both natural and synthetic fibers may be used for the manufacture of the woven or knitted ;
fabrics. Bandages which are required to have a cooling effect for the treatment of inflammatory swellings are usually dipped in water, but such swellings may also be treated with wet towels, handkerchiefs or other woven or knitted materials inqtead of bandages. The same method of treatment is also used for reducing high body temperatures, for example, in infants and small children. -In that case, wet towels or handkerchiefs are wrapped around the patient's calves. This procedure has numerous disadvantages. The main disadvantage is that textile materials of the above-mentioned type may only hold a very limited quantity of water and any excess would drip from the bandage and wet the surrounding areas.
It has now been found that the disadvantages of the bandages previouqly used may be overcome by using bandages made of materials based on polyurethane urea gels~
The materials used according to the present invention may consist of the gels alone or they may advantageously consist of combinations of the gels with any supporting layers of textile or non-textile products. These supporting layers may be bonded to the polyurethane on one or both sides.
The hydrogels and alcohol gels to be used according to the present invention, which are based on polyurethane polyureas, have been essentially disclosed in German DOS
2,347,299. They may be obtained by reacting isocyanate pre-polymers of polyethers containing at least 40YO o~ ethylene ~. ~
rA ~ - 1 -., j~ , .: '' ` .. :
``-`` 10~8733 , .
oxide units with diamines or higher polyamines or water as chain lengthening agents in the presence of water and/or alcohols as dispersing agents, as well as perfumes and optionally other additives. The term "gel" is used herein to described the physical nature of the gel-like end product rather than the exact polymer physical structure according to the present day views of the colloid chemistry of this state.
It has been found that bandages based on such gels, preferably polyurethane polyurea hydrogels, have numerous surprising advantages:
~ The water content in the gels may be greater than 9~h, by weight, and have any value below this figure.
The water is absolutely-firmly fixed in the polymer network even if the water content is 95%, by weight and will not migrate from the gels.
2. The gels are mechanically strong and may be elastically stretched. They are found to have a high ultimate tensile strength.
rA ~ - 1 -., j~ , .: '' ` .. :
``-`` 10~8733 , .
oxide units with diamines or higher polyamines or water as chain lengthening agents in the presence of water and/or alcohols as dispersing agents, as well as perfumes and optionally other additives. The term "gel" is used herein to described the physical nature of the gel-like end product rather than the exact polymer physical structure according to the present day views of the colloid chemistry of this state.
It has been found that bandages based on such gels, preferably polyurethane polyurea hydrogels, have numerous surprising advantages:
~ The water content in the gels may be greater than 9~h, by weight, and have any value below this figure.
The water is absolutely-firmly fixed in the polymer network even if the water content is 95%, by weight and will not migrate from the gels.
2. The gels are mechanically strong and may be elastically stretched. They are found to have a high ultimate tensile strength.
3. Syneresis does not take place when the gels or bandages are left to stand. The water is immobilized so that the gel may be regarded as consiting of "solid water".
4. The gels or bandages containing the gels may be frozen at temperatures below the freezing point of water without destruction of or damage to the gel structure.
Freezing is reversible and thawing and refreezing may be repeated indefinitely.
Freezing is reversible and thawing and refreezing may be repeated indefinitely.
5. When the bandage is applied, a cooling effect takes place and water is slowly liberated from the gel 30- or bandage. The water lost by this process may be restored to the polymer structure by leaving the gel or bandage in water, r - 2 -that is to say the liberation and absorption of water are reversible.
6. The gel products may easily be combined with the support materials. One particularly striking feature is the firm bond obtained between the gel and textile sheets.
7. The gel masses may easily be shaped. They may be obtained as flat structures or they may be converted into any desired shapes in suitable molds. This shaping is particularly useful if the dressings are required for the treatment of parts of the body which are difficult to bandage in the conventional way.
The present invention thus relates to the use, as dressing, of polyurethane urea gels-containing water and/or alcohols and optionally also comprising supporting layers, intermediate layers and/or covering layers.
In particular the invention relates to a bandage comprising (A) a polyurethane urea gel comprising (i) a polyaddition product of an isocyanate prepolymer which has been prepared from a polyisocyanate and a polyether polyol, said polyether polyol containing at least 4~/O, by weight, of ethylene oxide units, and a chain lengthening agent selected from the group consisting of water, polyamines and mixtures thereof, and (ii) 30 to 95%, by weight~ based on the total weight of the gel, of a dispersing agent selected from the group consisting of water, aliphatic monohydric alcohols, aliphatic polyhydric alcohols and mixtures thereof, (B) bonded to at least one textile support layer.
The present invention also relates to a process for the manufacture of bandages based on polyurethane urea gels containing water and/or alcohols, characterized in that isocyanate group-containing prepolymers which are obtained from ~' 10~8733 polyethers containing at least 4G%~ by weight, of ethylene oxide units are mixed with water and/or polyamine~ as chain lengthening agents in the presence of water and/or alcohols and optionally also perfumes, pharmaceutical preparation~
and other additives. The re~ulting mixture is applied to or ~-between layers of support materials before the components complete their reaction. This procedure is optionally accompanied by a shaping process.
In particular the invention relates to a process for the preparation of a bandage comprising i) preparing an isocyanate prepolymer from a polyisocyanate and a poly-ether polyol which contains at least 40 weight percent of ethylene oxide units, and ii) forming a polyurethane urea gel on a textile substrate by cross-linking said prepolymer with an agent selected from the group consisting of water, polyamines and mixture~ thereof in the presence of 30 to 95 wt. %, based on the weight of the gel, of a dispersing agent ~elected from the group consisting of water, aliphatic monohydric alcohols aliphatic polyhydric alcohols and mixtures ~-thereof.
Either water or alcohols or mixtures of both may be used for the preparation of the gels. The products of the process may therefore be divided into hydrogels and alcohol gels. The alcohols used may be either readily volatile monohydric alcohols, such as ethanol, isopropanol or butanol, or comparatively non-volatile polyhydric alcohols, such as ethylene glycol, diethylene glycol, glycerol or trimethylol-propane. In the preferred gels acc~rding to the present invention, at least 5~/0, by weight, of the dispersing agent consists of water.
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~ ~078733 Preparation of the gels may be carried out by various methods. For example, all the components, i.e., the prepolymer the dispersing agent, i.e. water and/or alcohol, perfumes, pharmacuetical preparations, chain lengthening agents and any other additives may be added all at once, but ~ey are - preferably added stepwise. In that case, the perfumes, pharmaceutical preparations and any other additives, as well as cross-linking agents if used, e.g, polyamines, are dis-solved in the dispersing agent. At the same time, an emulsion or solution of the prepolymer in the dispersing agent is prepared and the two batches are-then mixed in suitable stoi-chiometric proportions. The resulting mixture is poured - :
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- 4a -, , . ,., "
1~78'733 into molds or applied to textile or non-textile support materials. Whichever procedure is adopted, the reaction to form the gel which is used as bandage or part of a bandage takes place within a few seconds or minutes.
The end-product obtained may be a non-cellular solid or a foam, depending on the chain lengthening agent used.
Non-cellular gels are obtained when amines are used as chain lengthening agents. However, when water is used the products are foams due to the concomitant reaction of the isocyanate groups with water to produce gaseous carbon dioxide.
Vigorous mixing of the starting components facilitates the preparation of the gels and improves their quality.
In the simplest case, mixing may be achieved in a zone of high turbulence produced by mechanical stirrers. Better results are obtained by using high speed mixing apparatus, such as impeller homogenizers or mixing chambers with agitators of the type described in the literature or used in commercial polyurethane foaming machines. Vigorous mixing may also be achieved with the aid of mixing devices of polyurethane foaming machines in which the components are mixed by counterflow injection.
The gels may be poured or spread out to form endless webs of any desired thickness befoxe they are cross-linked, and, if desired, these webs may be profiled.
It is particularly advantageous to apply the gels to support materials before they are cross-linked. These support materials may consist, for example, of woven or knitted fabrics, non-woven webs, foils or mesh fabrics based on natural and/or synthetic polymers. These support LeA 16,684 -5-;:
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materials may also have a foam structure. Suitable foams for use as support materials are, in particular, the well known soft and semi-hard polyurethane foams. The thickness of the layers of gel may vary within wide limits and basically depends only on the requirements of the bandage. The gel layers generally have thicknesses of from about 1 to about 50 mm.
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The prepolymers used for the preparation of the gels, consisting of polyethers containing at least 40%,by weight, of ethylene oxide and of higher functional polyisocyanates still containing free isocyanate end groups, are prepared by reacting suitable polyethers with an excess quantity of polyisocyanate, i.e. using an isocyanate: hydroxyl ratio greater than 1:1, preferably from 1.5:1 to 20:1 and , 15 most preferably from 2:1 to 10:1.
The optimum ratio for carrying out the process depends on the molecular weight, functionality and structure of the polyether. The isocyanate contents of the prepolymers should generally be from about 2 to about 20%, by weight, preferably from 3.5 to 10%, by weight.
When amines are used as chain lengthening agents, the prepolymers and amines are required to be used in substantially stoichiometric quantities for producing the bandage gels, but when carrying out the process on a technical scale, it has been found that in order to obtain a suitable residence time of the reactants in the mixing assemblies it is advantageous to use an excess of amine component, i.e.
an NH2:NCO ratio greater than 1:1 and preferably from 1:1 to 1.2:1.
LeA 16,684 -6-.. . .
1078733 ~`
When water is used as chain lengthening agent, the isocyanate groups and water may also be used in stoi-chiometrically equivalent proportions. However, if desired and especially for producing foam gels, a substantially larger quantity of water may used. In that case, it is particularly advantageous also to use water as dispersing agent so that hydrogels in ~he form of foams are obtained.
Water in that case fulfills a double function, first as reactant for the reaction with isocyanate groups and second as dispersing agent.
The quantity of water and/or alcohol present when the gels are being formed may vary within wide limits and is not critical. The weight of alcohol and/or water may be up to 98%, based on the total mass of gel. However, the properties of the gels obtained are strongly influenced by the proportion of polymer to dispersing agent. As a general rule, the gels obtained are progressively more stable and harder with increasing polymer content and softer and structurally less rigid with decreasing polymer content down to the lower limit of about 2~, by weight.
The gels used according to the present invention preferably contain from about 30 to 95~, by weight, of water and/or alcohol.
It is particularly surprising that the gel-based bandages according to the present invention are exceptionally stable. Even after prolonged storage, the gels undergo no visible phase separation which would be noticed, for example, by the material becoming cloudy. The dimensional stability is preserved even when the gels are stored at elevated temperatures and again no phase separation is observed. The dispersing agent is very firmly fixed in the gel, but may be LeA 16,684 -7-liberated from it quite rapidly, depending on its vapor pressure, and the body of the gel then gradually shrinks proportionately to its external dimensions. At this stage, perfumes and pharmaceutical preparationsmay also diffuse 5 from the gel to be liberated to its surroundings, for example `~
to the patient's skin. The liberation of dispersing agent causes additional cooling, especially if the dispersing agent is water. The liberation and reabsorption of dis-persing agent from and into the gel is reversible. This means that when the gels have lost some of their dispersing agent, they may reabsorb fresh dispersing agent and build it into the polymer structure when stored in pure dispersing agent.
Another surprising characteristic of the gels is that they may be frozen and thawed repeatedly any number of times without destruction of their structure. This property is particularly advantageous when water is used as dispersing agent by virtue of its high thermal or cooling capacity.
The bandages according to the present invention may therefore be stored indefinitely in refrigerators or cooling chests until they are required.
The starting materials required for the ~els used according to the present invention include polyethers having a molecular weight of from about 500 to about 10,000, preferably from 2,000 to 8,000, which have at least two active hydrogen atoms and contain at least 40~, by weight, of ethylene oxide groups. Polyethers of this type may be prepared by reacting compounds containing reactive hydrogen atoms, e.g.
polyhydric alcohols, with ethylene oxide and optionally also other alkylene oxides, such as propylene oxide, butylene oxide, styrene oxide, epichlorohydrin or mixtures of these alkylene oxides.
LeA 16,684 -~-Suitable polyhydricalcohols and phenols include ethylene glycol, diethylene glycol, polyethylene glycol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, hexane-1,6-diol, decane-1,2-diol, butyne-2-diol-(1,4),glycerol, butane-2,4-diol, hexane-1,3,6-triol, trimethylolpropane, resorcinol, hydroquinone, 4,6-di-tert.-butyl pyrocatechol, 3-hydroxy-2-naphthol, 6,7-dihydroxy-1-naphthol, 2,5-dihydroxy-l-naphthol, 2,2-bis-(_-hydroxyphenyl)-propane, bis-(_-hydroxy-phenyl)-methane and ~ -tris-(hydroxyphenyl)-alkanes, such as 1,1,2-tris-(hydroxyphenyl)-ethane or 1,1,3-tris-(hydroxy-phenyl)-propane.
Other suitable polyethers include the 1,2-alkylene oxide derivatives of aliphatic or aromatic monoamines or poly-amines, such as ammonia, methylamine, ethylene diamine, N,N-dimethylethylenediamine, tetra- or hexamethylenediamine, diethylene triamine, ethanolamine, diethanolamine, oleyl-diethanolamine, methyl diethanolamine, triethanolamine, aminoethyl piperazine, o, _ and ~-phenylene diamine, 2,4-and 2,6-diaminotoluene, 2,6-diamino-~-xylene and multinuclear 20 and condensed aromatic polyamines, such as 1,4-naphthylene ~:
diamine, 1,5-naphthylene diamine, benzidine, toluidine, 2,2-dichloro-4,4'-diaminodiphenylmethane, l-fluorenamine, 1,4-anthradiamine, 9,10-diaminophenanthrene and 4,4'-diamino-azobenzene. Resinous materials, such as phenols and resols, may also be used as starting molecules for the polyethers.
Ethylene oxide is included in the synthesis of all these polyethers.
The starting components used according to the present invention also include aliphatic, cycloaliphatic, araliphatic, ;-LeA 16,684 -9-~078733 aromatic and heterocyclic polyisocyanates of the type which have been described, for example, by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136. The following are examples: ethylene diioscyanate; tetramethylene-1,4-diisocyanate; hexamethylene-1,6-diisocyanate; dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,3- and -1,4-diisocyanate and mixtures of these isomers;
l-isocyanato-3,3,5-trimethyl-5-isocyanato-methyl-cyclohexane (German Auslegeschrift No. 1,202,785); hexahydrotolylene-2,4- and -2,6-diisocyanate and mixtures of these isomers;
hexahydrophenylene-1,3- and/or -1,4-diisocyanate; perhydro-diphenylmethane-2,4'- and/or 4,4'-diisocyanate; phenylene-1,3- and-1,4-diisocyanate; tolylene-2,4- and -2,6-diisocyanate and mixtures of these isomers; diphenylmethane-2,4'- and/or 4,4'-diisocyanate; naphthylene-1,5-diisocyanate; triphenyl-methane-4,4',4"-triisocyanate; polyphenyl-polymethylene polyisocyanates which may be obtained by aniline-formaldehyde condensation followed by phosgenation and which have been described, for example, in British Patents 874,430 and 848,671; perchlorinated aryl polyisocyanates as described, e.g. in German Auslegeschrift No. 1,157,601; polyisocyanates containing carbodiimide groups as described in German Patent 1,092,007; the diisocyanates described in U.S. Patent 3,492,330; polyisocyanates having allophanate groups according to British Patent 994,890, Belgian Patent 761,626 and published Dutch Patent Application 7,102,524; polyisocyanates having ; isocyanurate groups as described, e.g. in German Patents 1,022,789; 1,222,067 and 1,027,394 and in German Offenlegung-sschrift Nos. 1,929,034 and 2,004,048; polyisocyanates having urethane groups as described, e.g. in Belgian Patent 752,261 or in U.S. Patent 3,394,164; polyisocyanates having acylated urea groups according to German Patent 1,230,778; poly-- LeA 16,684 -10-., : . : . . .
~(~78733 isocyanates containing biuret groups as described, e.g.
in German Patent 1,101,394, British Patent 889,050 and in French Patent 7,017,514; polyisocyanates prepared by telomerization reactions, e.g. as described in Belgian Patent 723,640; polyisocyanates containing ester groups as mentioned, e.g. in British Patents 956,474 and 1,072,956, in U.S. Patent 3,567,763 and in German Patent 1,231,688; and reaction products of the above-mentioned isocyanates with acetals according to German Patent 1,072,385.
The low molecular weight cross-linking or chain lengthening agents used may be aliphatic, cycloaliphatic, or aromatic diamines or higher polyamines, for example, ethylene diamine, hexamethylene diamine, diethylene triamine, hydrazine, guanidine carbonate, N,N'-bis-(3-aminopropyl)-ethylene diamine, N,N'-bis-(2-aminopropyl)-ethylenediamine, N,N'-bis-(2-aminoethyl)-ethylenediamine, 4,4'-dimethylamino-diphenylmethane, 4,4'-diamino-diphenyl-methane and 2,4-and 2,6-diaminotoluene.
Preparation of the prepolymers from polyethers and polyisocyanate is carried out by known methods, using NCO:OH
ratios greater than 1:1.
A considerable quantity of both water-soluble and water-insoluble additives (i.e. additives which may be 25 emulsified in water, if required with the addition of ;
dispersing agents) may be added to the reaction mixtures for preparing the gels used in the manufacture of the bandages.
Examples of suitable additives include: haemostatic agents, various pharmaceutical preparations, disinfectants, dyes, LeA 16,684 -11-perfumes and cosmetic preparations for the skin, for example to regulate its moisture content. Other suitable additives include natural or other synthetic gel formers, such as gelatin, carrageenates, alginates, polyvinyl alcohol and methyl cellulose. All these additives may be added to the gel compositions in quantities of up to about 20 volumes percent.
Considerable quantities (up to about 50 volume percent)of various fillers may also be added in the preparation of the gels. These include silicates obtained from various silicic acids, aluminum oxides, tin oxides, antimony tri-oxide, titanium dioxide, graphite and graphitic carbon, carbon black, retort carbon, air-borne sand, pulverulent cements and various inorganic and organic dye pigments, such as iron oxide pigments, lead chromate, lead oxide and red lead. Short or long fibers of natural or synthetic materials, for example powdered cellulose, may also be used as fillers.
` One advantage of using fillers is that it delays the liberation of the dispersing agent, i.e. of water and/or alcohol, as well as of any other additives, and therefore ~` prolongs the time during which the bandage may be left on the patient before it must be removed.
If desired, a gaseous component (generally air) may be added to the reaction mixture during gel formation.
Gel bandages with a foam structure are thereby obtained, ; in which the unit weight (kg/m ) is substantially lower than that of the non-cellular materials, depending on the ~` quantity of gas incorporated.
LeA 16,684 -12-,:
: ' One particular advantage of the process according to the present invention is that it may very easily be rendered continuous.
In a continuous process, the isocyanate prepolymers and, separately therefrom, the chain lengthening agent and dispersing agent are continuously introduced into a mixing zone at a temperature above the melting point and below the decomposition point of the isocyanate prepolymer and chain lengthening agent at such a rate that the isocyanate polyaddition reaction is not completed in the mixing zone.
The polyurethane gel obtained in a still fluid and deformable state with a high water or alcohol content is continuously removed from the mixing zone. If required, the still fluid gel is passed through a short reaction tube fitted with a shaped mouthpiece so that the resulting polyurethane gel is obtained as a completely shaped endless strand, band or sheet.
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This gel may then be used as a bandage on its own, but it is preferably combined with a support material.
This may be done by applying the vigorously mixed mass of gel continuously or intermittently to the textile or non-textile supports in conventional coating installations, for example, by means of coating knives or by brush ; coating or casting.
The bandages obtained in this way may be sold :~ open, but they are preferably sealed into waterproof foils which may be opened as required. This method of packaging may be carried out in conventional commercial automatic heat sealing machines.
LeA 16,684 -13-~78733 The term "bandage" used in this application is intended to encompass a broad category of materials made from the polyurethane urea gels. The opportunity to shape the gel allows for the bandage to be useful in a number of applications, particularly for the external treatment of animals or the human body for cosmetic and/or medicinal purposes. A bandage may be generally defined as a flexible strip or band used to cover, strengthen or compress the external body or to dress or bind up wounds. For example, the gels may be used as bandages for the treatment of inflammatory swellings, as leg compresses for reducing the body temperature of infants, as compresses for localized or general lowering of the body temperature, for carrying out operations on undercooled patients, and as face masks and ice packs.
LeA 16,684 -14-~078733 EXAMPLES
Example 1 ; (a) Preparation of the prepolymer:
159 parts, by weight, of tolylene diisocyanate (80% 2,4- and 20% 2,6-isomer) are heated to 80C in a reaction ; vessel.
1,200 parts, by weight, of a polyether having a polyhydroxyl number of 28 which has been obtained by the chemical addition of 60%, by weight, of ethylene oxide and 40%, by weight, of propylene oxide to glycerol are added dropwise with stirring over a period of 3 hours. The reaction mixture is then heated for one more hour at 80C
and left to cool to room temperature with stirring. The resulting prepolymer has an isocyanate content of 4.2%, by weight, and a viscosity of 5,200 centipoises at 25C.
(b) Manufacture of the bandage:
7 parts, by weight of the prepolymer described .=
under (a) are added to 59 partsj by weight, of water over a period of 3 seconds with mechanical stirring (rate of stirring 1165 revs/min). When the reaction mixture has been stirred for 50 seconds, it is poured into a mold.
~; The interior of the mold measures 25 x 8 x 0.5 cm. A cotton fabric (muslin bandage, 34 g/m2) 8 cm in width is placed longitudinally on the base measuring 25 x8 cm so that 10 cm of bandage overhangs the base at both ends.
60 seconds after the beginning of mixing, the reaction sets in with slight foaming (cream time). The gel time is 90 seconds. 10 minutes later, the foaming reaction is ccmpleted. The shaped product is removed from the mold after 5 minutes and sealed into an aluminum foil which LeA 16,684 -15-1~178733 has been coated with polyethylene on the side facing the bandage. The density of the gel product is 660 kg/m3.
The sealed bandage is stored at -20C for 24 hours.
The water in the bandage i8 then left to thaw and return to room temperature. The use properties of the bandage are not altered even when this process is repeated several times.
Example 2 The procedure is exactly the same as in Example l(b), but a polyamide-based fabric with a mesh of 1 mm and a weight of 130 g/m2 is used instead of the cotton fabric.
Example 3 The procedure is exactly the same as in Example l(b), but a polyamine -based fabric (130 g/m2) i9 used insted of a cotton fabric and a polyethylene foil con-forming to the dimensions of the base of the mold (25 x 8 cm) is placed on the reaction mixture at the beginning of the reaction so that the mixture is completely covered by the ~ foil.
i~ 20 Example 4 '~' The procedure is exactly the same as in Example l(b), but in~tead of 59 parts, by weight, of water there - is used an emulsion of 0.2 parts, by weight, of a dye of color index No. 42,085, 3.5 parts, by weight, of a perfume oil (mixture of 60%, by weight, of isobornyl acetate and 40%, by weight, of the condensation product of 1 mol of nonyl phenol and 10 mol of ethylene oxide) and 55.3 parts, by weight, of water.
LeA 16,684 -16-, 1~78733 Example 5 The procedure is exactly the same as in Example l(b), but the 59 parts, by weight, of water are replaced by an emulsion of 56 parts, by weight, of water and 3 parts, by weight, of an ointment for cuts and burns having the following composition: Phenolum liquefactum 1 g, Bismutum sUbgallicum S g, Emplastrum Lithargyri 20 g, ointment base ; ad 100 g.
Example 6 The procedure is exactly as in Example l(b), but using a suspension of 55 parts, by weight, of water and 4 parts, by weight, of pulverulent titanium dioxide instead of 59 parts, by weight, of water.
Example 7 The procedure is exactly the same as in Example l(b), but using a mixture of 46 parts, by weight, of water and 13 par~s, by weight, of propan-2-ol instead of 59 parts, by weight, of water.
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. Example 8 The procedure is exactly the same as in Example l(b), but the reaction mixture used is a mixture of 9O5 parts, by weight, of the prepolymer described in Example l(a) and 53.5 parts, by weight, of a solution consisting of 52 parts, by weight, of water and 1.5 parts, by weight, of the aluminum salt of acetic acid. The gel mass has a density of 630 kg/m .
LeA 16,684 -17-107~733 Example 9 The procedure is exactly the same as in Example 1 (b), but the reaction mixture used is a mixture of 9.5 parts, by weight, of the prepolymer described in Example l(a), and 53.5 parts, by weight, of a mixture of 52 parts, by weight, of water and 1.5 parts, by weight, of menthol.
Measured from the beginning of the process of mixing the two reactants, the stirring time is 45 seconds, the cream time 60 seconds and the gel time 70 seconds. The density of the gel i= 630 kg/m3.
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LeA 16,684 -18-
The present invention thus relates to the use, as dressing, of polyurethane urea gels-containing water and/or alcohols and optionally also comprising supporting layers, intermediate layers and/or covering layers.
In particular the invention relates to a bandage comprising (A) a polyurethane urea gel comprising (i) a polyaddition product of an isocyanate prepolymer which has been prepared from a polyisocyanate and a polyether polyol, said polyether polyol containing at least 4~/O, by weight, of ethylene oxide units, and a chain lengthening agent selected from the group consisting of water, polyamines and mixtures thereof, and (ii) 30 to 95%, by weight~ based on the total weight of the gel, of a dispersing agent selected from the group consisting of water, aliphatic monohydric alcohols, aliphatic polyhydric alcohols and mixtures thereof, (B) bonded to at least one textile support layer.
The present invention also relates to a process for the manufacture of bandages based on polyurethane urea gels containing water and/or alcohols, characterized in that isocyanate group-containing prepolymers which are obtained from ~' 10~8733 polyethers containing at least 4G%~ by weight, of ethylene oxide units are mixed with water and/or polyamine~ as chain lengthening agents in the presence of water and/or alcohols and optionally also perfumes, pharmaceutical preparation~
and other additives. The re~ulting mixture is applied to or ~-between layers of support materials before the components complete their reaction. This procedure is optionally accompanied by a shaping process.
In particular the invention relates to a process for the preparation of a bandage comprising i) preparing an isocyanate prepolymer from a polyisocyanate and a poly-ether polyol which contains at least 40 weight percent of ethylene oxide units, and ii) forming a polyurethane urea gel on a textile substrate by cross-linking said prepolymer with an agent selected from the group consisting of water, polyamines and mixture~ thereof in the presence of 30 to 95 wt. %, based on the weight of the gel, of a dispersing agent ~elected from the group consisting of water, aliphatic monohydric alcohols aliphatic polyhydric alcohols and mixtures ~-thereof.
Either water or alcohols or mixtures of both may be used for the preparation of the gels. The products of the process may therefore be divided into hydrogels and alcohol gels. The alcohols used may be either readily volatile monohydric alcohols, such as ethanol, isopropanol or butanol, or comparatively non-volatile polyhydric alcohols, such as ethylene glycol, diethylene glycol, glycerol or trimethylol-propane. In the preferred gels acc~rding to the present invention, at least 5~/0, by weight, of the dispersing agent consists of water.
. .
; . .:
, . . . -:
~ ~078733 Preparation of the gels may be carried out by various methods. For example, all the components, i.e., the prepolymer the dispersing agent, i.e. water and/or alcohol, perfumes, pharmacuetical preparations, chain lengthening agents and any other additives may be added all at once, but ~ey are - preferably added stepwise. In that case, the perfumes, pharmaceutical preparations and any other additives, as well as cross-linking agents if used, e.g, polyamines, are dis-solved in the dispersing agent. At the same time, an emulsion or solution of the prepolymer in the dispersing agent is prepared and the two batches are-then mixed in suitable stoi-chiometric proportions. The resulting mixture is poured - :
..
- 4a -, , . ,., "
1~78'733 into molds or applied to textile or non-textile support materials. Whichever procedure is adopted, the reaction to form the gel which is used as bandage or part of a bandage takes place within a few seconds or minutes.
The end-product obtained may be a non-cellular solid or a foam, depending on the chain lengthening agent used.
Non-cellular gels are obtained when amines are used as chain lengthening agents. However, when water is used the products are foams due to the concomitant reaction of the isocyanate groups with water to produce gaseous carbon dioxide.
Vigorous mixing of the starting components facilitates the preparation of the gels and improves their quality.
In the simplest case, mixing may be achieved in a zone of high turbulence produced by mechanical stirrers. Better results are obtained by using high speed mixing apparatus, such as impeller homogenizers or mixing chambers with agitators of the type described in the literature or used in commercial polyurethane foaming machines. Vigorous mixing may also be achieved with the aid of mixing devices of polyurethane foaming machines in which the components are mixed by counterflow injection.
The gels may be poured or spread out to form endless webs of any desired thickness befoxe they are cross-linked, and, if desired, these webs may be profiled.
It is particularly advantageous to apply the gels to support materials before they are cross-linked. These support materials may consist, for example, of woven or knitted fabrics, non-woven webs, foils or mesh fabrics based on natural and/or synthetic polymers. These support LeA 16,684 -5-;:
.
materials may also have a foam structure. Suitable foams for use as support materials are, in particular, the well known soft and semi-hard polyurethane foams. The thickness of the layers of gel may vary within wide limits and basically depends only on the requirements of the bandage. The gel layers generally have thicknesses of from about 1 to about 50 mm.
. :
The prepolymers used for the preparation of the gels, consisting of polyethers containing at least 40%,by weight, of ethylene oxide and of higher functional polyisocyanates still containing free isocyanate end groups, are prepared by reacting suitable polyethers with an excess quantity of polyisocyanate, i.e. using an isocyanate: hydroxyl ratio greater than 1:1, preferably from 1.5:1 to 20:1 and , 15 most preferably from 2:1 to 10:1.
The optimum ratio for carrying out the process depends on the molecular weight, functionality and structure of the polyether. The isocyanate contents of the prepolymers should generally be from about 2 to about 20%, by weight, preferably from 3.5 to 10%, by weight.
When amines are used as chain lengthening agents, the prepolymers and amines are required to be used in substantially stoichiometric quantities for producing the bandage gels, but when carrying out the process on a technical scale, it has been found that in order to obtain a suitable residence time of the reactants in the mixing assemblies it is advantageous to use an excess of amine component, i.e.
an NH2:NCO ratio greater than 1:1 and preferably from 1:1 to 1.2:1.
LeA 16,684 -6-.. . .
1078733 ~`
When water is used as chain lengthening agent, the isocyanate groups and water may also be used in stoi-chiometrically equivalent proportions. However, if desired and especially for producing foam gels, a substantially larger quantity of water may used. In that case, it is particularly advantageous also to use water as dispersing agent so that hydrogels in ~he form of foams are obtained.
Water in that case fulfills a double function, first as reactant for the reaction with isocyanate groups and second as dispersing agent.
The quantity of water and/or alcohol present when the gels are being formed may vary within wide limits and is not critical. The weight of alcohol and/or water may be up to 98%, based on the total mass of gel. However, the properties of the gels obtained are strongly influenced by the proportion of polymer to dispersing agent. As a general rule, the gels obtained are progressively more stable and harder with increasing polymer content and softer and structurally less rigid with decreasing polymer content down to the lower limit of about 2~, by weight.
The gels used according to the present invention preferably contain from about 30 to 95~, by weight, of water and/or alcohol.
It is particularly surprising that the gel-based bandages according to the present invention are exceptionally stable. Even after prolonged storage, the gels undergo no visible phase separation which would be noticed, for example, by the material becoming cloudy. The dimensional stability is preserved even when the gels are stored at elevated temperatures and again no phase separation is observed. The dispersing agent is very firmly fixed in the gel, but may be LeA 16,684 -7-liberated from it quite rapidly, depending on its vapor pressure, and the body of the gel then gradually shrinks proportionately to its external dimensions. At this stage, perfumes and pharmaceutical preparationsmay also diffuse 5 from the gel to be liberated to its surroundings, for example `~
to the patient's skin. The liberation of dispersing agent causes additional cooling, especially if the dispersing agent is water. The liberation and reabsorption of dis-persing agent from and into the gel is reversible. This means that when the gels have lost some of their dispersing agent, they may reabsorb fresh dispersing agent and build it into the polymer structure when stored in pure dispersing agent.
Another surprising characteristic of the gels is that they may be frozen and thawed repeatedly any number of times without destruction of their structure. This property is particularly advantageous when water is used as dispersing agent by virtue of its high thermal or cooling capacity.
The bandages according to the present invention may therefore be stored indefinitely in refrigerators or cooling chests until they are required.
The starting materials required for the ~els used according to the present invention include polyethers having a molecular weight of from about 500 to about 10,000, preferably from 2,000 to 8,000, which have at least two active hydrogen atoms and contain at least 40~, by weight, of ethylene oxide groups. Polyethers of this type may be prepared by reacting compounds containing reactive hydrogen atoms, e.g.
polyhydric alcohols, with ethylene oxide and optionally also other alkylene oxides, such as propylene oxide, butylene oxide, styrene oxide, epichlorohydrin or mixtures of these alkylene oxides.
LeA 16,684 -~-Suitable polyhydricalcohols and phenols include ethylene glycol, diethylene glycol, polyethylene glycol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, hexane-1,6-diol, decane-1,2-diol, butyne-2-diol-(1,4),glycerol, butane-2,4-diol, hexane-1,3,6-triol, trimethylolpropane, resorcinol, hydroquinone, 4,6-di-tert.-butyl pyrocatechol, 3-hydroxy-2-naphthol, 6,7-dihydroxy-1-naphthol, 2,5-dihydroxy-l-naphthol, 2,2-bis-(_-hydroxyphenyl)-propane, bis-(_-hydroxy-phenyl)-methane and ~ -tris-(hydroxyphenyl)-alkanes, such as 1,1,2-tris-(hydroxyphenyl)-ethane or 1,1,3-tris-(hydroxy-phenyl)-propane.
Other suitable polyethers include the 1,2-alkylene oxide derivatives of aliphatic or aromatic monoamines or poly-amines, such as ammonia, methylamine, ethylene diamine, N,N-dimethylethylenediamine, tetra- or hexamethylenediamine, diethylene triamine, ethanolamine, diethanolamine, oleyl-diethanolamine, methyl diethanolamine, triethanolamine, aminoethyl piperazine, o, _ and ~-phenylene diamine, 2,4-and 2,6-diaminotoluene, 2,6-diamino-~-xylene and multinuclear 20 and condensed aromatic polyamines, such as 1,4-naphthylene ~:
diamine, 1,5-naphthylene diamine, benzidine, toluidine, 2,2-dichloro-4,4'-diaminodiphenylmethane, l-fluorenamine, 1,4-anthradiamine, 9,10-diaminophenanthrene and 4,4'-diamino-azobenzene. Resinous materials, such as phenols and resols, may also be used as starting molecules for the polyethers.
Ethylene oxide is included in the synthesis of all these polyethers.
The starting components used according to the present invention also include aliphatic, cycloaliphatic, araliphatic, ;-LeA 16,684 -9-~078733 aromatic and heterocyclic polyisocyanates of the type which have been described, for example, by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136. The following are examples: ethylene diioscyanate; tetramethylene-1,4-diisocyanate; hexamethylene-1,6-diisocyanate; dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,3- and -1,4-diisocyanate and mixtures of these isomers;
l-isocyanato-3,3,5-trimethyl-5-isocyanato-methyl-cyclohexane (German Auslegeschrift No. 1,202,785); hexahydrotolylene-2,4- and -2,6-diisocyanate and mixtures of these isomers;
hexahydrophenylene-1,3- and/or -1,4-diisocyanate; perhydro-diphenylmethane-2,4'- and/or 4,4'-diisocyanate; phenylene-1,3- and-1,4-diisocyanate; tolylene-2,4- and -2,6-diisocyanate and mixtures of these isomers; diphenylmethane-2,4'- and/or 4,4'-diisocyanate; naphthylene-1,5-diisocyanate; triphenyl-methane-4,4',4"-triisocyanate; polyphenyl-polymethylene polyisocyanates which may be obtained by aniline-formaldehyde condensation followed by phosgenation and which have been described, for example, in British Patents 874,430 and 848,671; perchlorinated aryl polyisocyanates as described, e.g. in German Auslegeschrift No. 1,157,601; polyisocyanates containing carbodiimide groups as described in German Patent 1,092,007; the diisocyanates described in U.S. Patent 3,492,330; polyisocyanates having allophanate groups according to British Patent 994,890, Belgian Patent 761,626 and published Dutch Patent Application 7,102,524; polyisocyanates having ; isocyanurate groups as described, e.g. in German Patents 1,022,789; 1,222,067 and 1,027,394 and in German Offenlegung-sschrift Nos. 1,929,034 and 2,004,048; polyisocyanates having urethane groups as described, e.g. in Belgian Patent 752,261 or in U.S. Patent 3,394,164; polyisocyanates having acylated urea groups according to German Patent 1,230,778; poly-- LeA 16,684 -10-., : . : . . .
~(~78733 isocyanates containing biuret groups as described, e.g.
in German Patent 1,101,394, British Patent 889,050 and in French Patent 7,017,514; polyisocyanates prepared by telomerization reactions, e.g. as described in Belgian Patent 723,640; polyisocyanates containing ester groups as mentioned, e.g. in British Patents 956,474 and 1,072,956, in U.S. Patent 3,567,763 and in German Patent 1,231,688; and reaction products of the above-mentioned isocyanates with acetals according to German Patent 1,072,385.
The low molecular weight cross-linking or chain lengthening agents used may be aliphatic, cycloaliphatic, or aromatic diamines or higher polyamines, for example, ethylene diamine, hexamethylene diamine, diethylene triamine, hydrazine, guanidine carbonate, N,N'-bis-(3-aminopropyl)-ethylene diamine, N,N'-bis-(2-aminopropyl)-ethylenediamine, N,N'-bis-(2-aminoethyl)-ethylenediamine, 4,4'-dimethylamino-diphenylmethane, 4,4'-diamino-diphenyl-methane and 2,4-and 2,6-diaminotoluene.
Preparation of the prepolymers from polyethers and polyisocyanate is carried out by known methods, using NCO:OH
ratios greater than 1:1.
A considerable quantity of both water-soluble and water-insoluble additives (i.e. additives which may be 25 emulsified in water, if required with the addition of ;
dispersing agents) may be added to the reaction mixtures for preparing the gels used in the manufacture of the bandages.
Examples of suitable additives include: haemostatic agents, various pharmaceutical preparations, disinfectants, dyes, LeA 16,684 -11-perfumes and cosmetic preparations for the skin, for example to regulate its moisture content. Other suitable additives include natural or other synthetic gel formers, such as gelatin, carrageenates, alginates, polyvinyl alcohol and methyl cellulose. All these additives may be added to the gel compositions in quantities of up to about 20 volumes percent.
Considerable quantities (up to about 50 volume percent)of various fillers may also be added in the preparation of the gels. These include silicates obtained from various silicic acids, aluminum oxides, tin oxides, antimony tri-oxide, titanium dioxide, graphite and graphitic carbon, carbon black, retort carbon, air-borne sand, pulverulent cements and various inorganic and organic dye pigments, such as iron oxide pigments, lead chromate, lead oxide and red lead. Short or long fibers of natural or synthetic materials, for example powdered cellulose, may also be used as fillers.
` One advantage of using fillers is that it delays the liberation of the dispersing agent, i.e. of water and/or alcohol, as well as of any other additives, and therefore ~` prolongs the time during which the bandage may be left on the patient before it must be removed.
If desired, a gaseous component (generally air) may be added to the reaction mixture during gel formation.
Gel bandages with a foam structure are thereby obtained, ; in which the unit weight (kg/m ) is substantially lower than that of the non-cellular materials, depending on the ~` quantity of gas incorporated.
LeA 16,684 -12-,:
: ' One particular advantage of the process according to the present invention is that it may very easily be rendered continuous.
In a continuous process, the isocyanate prepolymers and, separately therefrom, the chain lengthening agent and dispersing agent are continuously introduced into a mixing zone at a temperature above the melting point and below the decomposition point of the isocyanate prepolymer and chain lengthening agent at such a rate that the isocyanate polyaddition reaction is not completed in the mixing zone.
The polyurethane gel obtained in a still fluid and deformable state with a high water or alcohol content is continuously removed from the mixing zone. If required, the still fluid gel is passed through a short reaction tube fitted with a shaped mouthpiece so that the resulting polyurethane gel is obtained as a completely shaped endless strand, band or sheet.
. .
This gel may then be used as a bandage on its own, but it is preferably combined with a support material.
This may be done by applying the vigorously mixed mass of gel continuously or intermittently to the textile or non-textile supports in conventional coating installations, for example, by means of coating knives or by brush ; coating or casting.
The bandages obtained in this way may be sold :~ open, but they are preferably sealed into waterproof foils which may be opened as required. This method of packaging may be carried out in conventional commercial automatic heat sealing machines.
LeA 16,684 -13-~78733 The term "bandage" used in this application is intended to encompass a broad category of materials made from the polyurethane urea gels. The opportunity to shape the gel allows for the bandage to be useful in a number of applications, particularly for the external treatment of animals or the human body for cosmetic and/or medicinal purposes. A bandage may be generally defined as a flexible strip or band used to cover, strengthen or compress the external body or to dress or bind up wounds. For example, the gels may be used as bandages for the treatment of inflammatory swellings, as leg compresses for reducing the body temperature of infants, as compresses for localized or general lowering of the body temperature, for carrying out operations on undercooled patients, and as face masks and ice packs.
LeA 16,684 -14-~078733 EXAMPLES
Example 1 ; (a) Preparation of the prepolymer:
159 parts, by weight, of tolylene diisocyanate (80% 2,4- and 20% 2,6-isomer) are heated to 80C in a reaction ; vessel.
1,200 parts, by weight, of a polyether having a polyhydroxyl number of 28 which has been obtained by the chemical addition of 60%, by weight, of ethylene oxide and 40%, by weight, of propylene oxide to glycerol are added dropwise with stirring over a period of 3 hours. The reaction mixture is then heated for one more hour at 80C
and left to cool to room temperature with stirring. The resulting prepolymer has an isocyanate content of 4.2%, by weight, and a viscosity of 5,200 centipoises at 25C.
(b) Manufacture of the bandage:
7 parts, by weight of the prepolymer described .=
under (a) are added to 59 partsj by weight, of water over a period of 3 seconds with mechanical stirring (rate of stirring 1165 revs/min). When the reaction mixture has been stirred for 50 seconds, it is poured into a mold.
~; The interior of the mold measures 25 x 8 x 0.5 cm. A cotton fabric (muslin bandage, 34 g/m2) 8 cm in width is placed longitudinally on the base measuring 25 x8 cm so that 10 cm of bandage overhangs the base at both ends.
60 seconds after the beginning of mixing, the reaction sets in with slight foaming (cream time). The gel time is 90 seconds. 10 minutes later, the foaming reaction is ccmpleted. The shaped product is removed from the mold after 5 minutes and sealed into an aluminum foil which LeA 16,684 -15-1~178733 has been coated with polyethylene on the side facing the bandage. The density of the gel product is 660 kg/m3.
The sealed bandage is stored at -20C for 24 hours.
The water in the bandage i8 then left to thaw and return to room temperature. The use properties of the bandage are not altered even when this process is repeated several times.
Example 2 The procedure is exactly the same as in Example l(b), but a polyamide-based fabric with a mesh of 1 mm and a weight of 130 g/m2 is used instead of the cotton fabric.
Example 3 The procedure is exactly the same as in Example l(b), but a polyamine -based fabric (130 g/m2) i9 used insted of a cotton fabric and a polyethylene foil con-forming to the dimensions of the base of the mold (25 x 8 cm) is placed on the reaction mixture at the beginning of the reaction so that the mixture is completely covered by the ~ foil.
i~ 20 Example 4 '~' The procedure is exactly the same as in Example l(b), but in~tead of 59 parts, by weight, of water there - is used an emulsion of 0.2 parts, by weight, of a dye of color index No. 42,085, 3.5 parts, by weight, of a perfume oil (mixture of 60%, by weight, of isobornyl acetate and 40%, by weight, of the condensation product of 1 mol of nonyl phenol and 10 mol of ethylene oxide) and 55.3 parts, by weight, of water.
LeA 16,684 -16-, 1~78733 Example 5 The procedure is exactly the same as in Example l(b), but the 59 parts, by weight, of water are replaced by an emulsion of 56 parts, by weight, of water and 3 parts, by weight, of an ointment for cuts and burns having the following composition: Phenolum liquefactum 1 g, Bismutum sUbgallicum S g, Emplastrum Lithargyri 20 g, ointment base ; ad 100 g.
Example 6 The procedure is exactly as in Example l(b), but using a suspension of 55 parts, by weight, of water and 4 parts, by weight, of pulverulent titanium dioxide instead of 59 parts, by weight, of water.
Example 7 The procedure is exactly the same as in Example l(b), but using a mixture of 46 parts, by weight, of water and 13 par~s, by weight, of propan-2-ol instead of 59 parts, by weight, of water.
., .
. Example 8 The procedure is exactly the same as in Example l(b), but the reaction mixture used is a mixture of 9O5 parts, by weight, of the prepolymer described in Example l(a) and 53.5 parts, by weight, of a solution consisting of 52 parts, by weight, of water and 1.5 parts, by weight, of the aluminum salt of acetic acid. The gel mass has a density of 630 kg/m .
LeA 16,684 -17-107~733 Example 9 The procedure is exactly the same as in Example 1 (b), but the reaction mixture used is a mixture of 9.5 parts, by weight, of the prepolymer described in Example l(a), and 53.5 parts, by weight, of a mixture of 52 parts, by weight, of water and 1.5 parts, by weight, of menthol.
Measured from the beginning of the process of mixing the two reactants, the stirring time is 45 seconds, the cream time 60 seconds and the gel time 70 seconds. The density of the gel i= 630 kg/m3.
., , ., :
:.
LeA 16,684 -18-
Claims (18)
1. A bandage comprising (A) a polyurethane urea gel comprising (i) a polyaddition product of an isocyanate prepolymer which has been prepared from a polyisocyanate and a polyether polyol, said polyether polyol containing at least 40%, by weight, of ethylene oxide units, and a chain lengthening agent selected from the group consisting of water, poly-amines and mixtures thereof, and (ii) 30 to 95%, by weight, based on the total weight of the gel, of a dispersing agent selected from the group consisting of water, aliphatic monohydric alcohols, aliphatic polyhydric alcohols and mixtures thereof, (B) bonded to at least one textile support layer.
2. A bandage according to claim 1, wherein said dispersing agent comprises a monohydric alcohol selected from the group consisting of ethanol, isopropanol and butanol.
3. A bandage according to claim 1, wherein said dispersing agent comprises a polyhydric alcohol selected from the group consisting of ethylene glycol, diethylene glycol, glycerol and trimethylolpropane.
4. A bandage according to claim 1, wherein at least 50% by weight of said dispersing agent consists of water.
5. A bandage according to claim 1, wherein said gel is a hydrogel.
6. A bandage according to claim 1, 2 or 3, wherein said gel is an alcohol gel.
7. A bandage according to claim 1, 2 or 3, wherein said gel forms a layer having a thickness of from about 1 to about 50 mm.
8. A bandage according to claim 5, wherein said gel forms a layer having a thickness of from about 1 to about 50 mm.
9. A bandage according to claim 1, wherein said isocyanate prepolymer is prepared by reacting said poly-isocyanate and said polyether polyol in an isocyanate:
hydroxyl ratio of 1.5:1 to 20:1.
hydroxyl ratio of 1.5:1 to 20:1.
10. A bandage according to claim 1, wherein said isocyanate prepolymer is prepared by reacting said poly-isocyanate and said polyether polyol, in an isocyanate:
hydroxyl ratio of 2:1 to 10:1.
hydroxyl ratio of 2:1 to 10:1.
11. A bandage according to claim 1, 4 or 10, wherein said prepolymer has an isocyanate content of 3.5 to 10%, by weight.
12. A bandage according to claim 1, 4 or 10, wherein said chain lengthening agent is a polyamine, said polyamine being reacted with said prepolymer in a NH2:NCO ratio of 1:1 to 1.2:1.
13. A bandage according to claim 1 or 4, wherein said chain lengthening agent is water.
14. A bandage according to claim 1, 4 or 10, wherein said polyether polyol has a molecular weight of 2,000 to 8,000.
15. A bandage comprising a layer of a polyurethane urea gel comprising i) a polyaddition product of a) an isocyanate prepolymer prepared by reacting a polyisocyanate and a polyether polyol in an isocyanate:hydroxyl ratio of 2:1 to 10:1, said polyether polyol having a molecular weight from 2,000 to 8,000, having at least two active hydrogen atoms and containing at least 40%, by weight, of ethylene oxide units, and b) at least one chain lengthening agent selected from the group consisting of-water and polyamines, ii) 30 to 95%, by weight, based on the total weight of the gel of a dispersing agent selected from the group consisting of a) water, b) a monohydric alcohol selected from the group consisting of ethanol, isopropanol and butanol, and c) a polyhydric alcohol selected from the group consisting of ethylene glycol, di-ethylene glycol, glycerol and trimethylol-propane, said layer having a thickness of about 1 to about 50 mm, and bonded to at least one textile support layer.
16. A process for the preparation of a bandage com-prising i) preparing an isocyanate prepolymer from a poly-isocyanate and a polyether polyol which contains at least 40 wt. % of ethylene oxide units, and ii) forming a polyurethane urea gel on a textile substrate by cross-linking said prepolymer with an agent selected from the group consisting of water, polyamines and mixtures thereof in the presence of 30 to 95 wt. %, based on the weight of the gel, of a dispersing agent selected from the group consisting of water, aliphatic mono-hydric alcohols aliphatic polyhydric alcohols and mixtures thereof.
17. A process according to claim 16, wherein in step ii) said gel is formed on said substrate as a layer having a thickness of about 1 to about 50 mm.
18. A process according to claim 16 or 17, wherein step ii) comprises applying a mixture of the polyurethane gel forming components to said textile substrate and effecting said cross-linking.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2538716A DE2538716C3 (en) | 1975-08-30 | 1975-08-30 | Gel-based dressings |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078733A true CA1078733A (en) | 1980-06-03 |
Family
ID=5955263
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA258,926A Expired CA1078733A (en) | 1975-08-30 | 1976-08-11 | Bandages containing polyurethane urea gels |
Country Status (13)
| Country | Link |
|---|---|
| JP (1) | JPS5915653B2 (en) |
| AT (1) | AT361128B (en) |
| BE (1) | BE845658A (en) |
| BR (1) | BR7605620A (en) |
| CA (1) | CA1078733A (en) |
| CH (1) | CH630530A5 (en) |
| DE (1) | DE2538716C3 (en) |
| ES (1) | ES451041A1 (en) |
| FR (1) | FR2321901A1 (en) |
| GB (1) | GB1489052A (en) |
| IT (1) | IT1066342B (en) |
| NL (1) | NL7609583A (en) |
| SE (1) | SE426358B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3224382A1 (en) * | 1982-06-30 | 1984-01-12 | Beiersdorf Ag, 2000 Hamburg | HYDROGEL-BASED FABRIC MATERIAL AND METHOD FOR THE PRODUCTION THEREOF |
| GB2188055B (en) * | 1986-03-20 | 1989-12-28 | Smith & Nephew Ass | Hydrophilic polyurethane foams |
| GB8606988D0 (en) * | 1986-03-20 | 1986-04-23 | Smith & Nephew Ass | Foams |
| US4795764A (en) * | 1987-06-01 | 1989-01-03 | Minnesota Mining & Manufacturing Company | Poly(oxyalkylene) poly(aliphatic isocyanate) prepolymer and polyurea polymer derived therefrom by reaction with polyamine |
| CA2447782C (en) | 2001-05-21 | 2009-10-20 | Huntsman International Llc | Very soft polyurethane elastomer |
| DE102010061474B4 (en) | 2010-04-07 | 2012-10-18 | Ilona Rabi-Hack | Medical wrap |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3419006A (en) * | 1966-08-08 | 1968-12-31 | Union Carbide Corp | Novel dressing and use thereof |
| CA1042600A (en) * | 1972-05-03 | 1978-11-14 | Louis L. Wood | Crosslinked hydrophilic polyurethane foams |
| US3939123A (en) * | 1974-06-18 | 1976-02-17 | Union Carbide Corporation | Lightly cross-linked polyurethane hydrogels based on poly(alkylene ether) polyols |
| US3939105A (en) * | 1974-06-18 | 1976-02-17 | Union Carbide Corporation | Microporous polyurethane hydrogels, method and composites with natural and other synthetic fibers or films |
-
1975
- 1975-08-30 DE DE2538716A patent/DE2538716C3/en not_active Expired
-
1976
- 1976-08-11 CA CA258,926A patent/CA1078733A/en not_active Expired
- 1976-08-25 CH CH1078576A patent/CH630530A5/en not_active IP Right Cessation
- 1976-08-25 GB GB35331/76A patent/GB1489052A/en not_active Expired
- 1976-08-26 BR BR7605620A patent/BR7605620A/en unknown
- 1976-08-26 SE SE7609461A patent/SE426358B/en unknown
- 1976-08-27 ES ES451041A patent/ES451041A1/en not_active Expired
- 1976-08-27 AT AT637876A patent/AT361128B/en not_active IP Right Cessation
- 1976-08-27 IT IT51049/76A patent/IT1066342B/en active
- 1976-08-27 NL NL7609583A patent/NL7609583A/en not_active Application Discontinuation
- 1976-08-30 JP JP51102738A patent/JPS5915653B2/en not_active Expired
- 1976-08-30 BE BE170193A patent/BE845658A/en not_active IP Right Cessation
- 1976-08-30 FR FR7626158A patent/FR2321901A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| BR7605620A (en) | 1977-08-09 |
| SE426358B (en) | 1983-01-17 |
| DE2538716B2 (en) | 1980-07-31 |
| AU1709876A (en) | 1978-03-02 |
| FR2321901B1 (en) | 1980-08-01 |
| ES451041A1 (en) | 1977-12-16 |
| IT1066342B (en) | 1985-03-04 |
| AT361128B (en) | 1981-02-25 |
| FR2321901A1 (en) | 1977-03-25 |
| BE845658A (en) | 1977-02-28 |
| DE2538716A1 (en) | 1977-03-10 |
| GB1489052A (en) | 1977-10-19 |
| ATA637876A (en) | 1980-07-15 |
| CH630530A5 (en) | 1982-06-30 |
| NL7609583A (en) | 1977-03-02 |
| JPS5230094A (en) | 1977-03-07 |
| SE7609461L (en) | 1977-03-01 |
| JPS5915653B2 (en) | 1984-04-11 |
| DE2538716C3 (en) | 1981-03-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |