CA2114411A1 - Polyurethane foams - Google Patents
Polyurethane foamsInfo
- Publication number
- CA2114411A1 CA2114411A1 CA002114411A CA2114411A CA2114411A1 CA 2114411 A1 CA2114411 A1 CA 2114411A1 CA 002114411 A CA002114411 A CA 002114411A CA 2114411 A CA2114411 A CA 2114411A CA 2114411 A1 CA2114411 A1 CA 2114411A1
- Authority
- CA
- Canada
- Prior art keywords
- isocyanate
- foam
- prepolymer
- ether
- aliphatic
- 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.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/721—Two or more polyisocyanates not provided for in one single group C08G18/73 - C08G18/80
- C08G18/724—Combination of aromatic polyisocyanates with (cyclo)aliphatic polyisocyanates
-
- 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
-
- 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
- A61L15/42—Use of materials characterised by their function or physical properties
- A61L15/425—Porous materials, e.g. foams or sponges
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/2805—Compounds having only one group containing active hydrogen
- C08G18/2815—Monohydroxy compounds
- C08G18/283—Compounds containing ether groups, e.g. oxyalkylated monohydroxy compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/48—Polyethers
- C08G18/4833—Polyethers containing oxyethylene units
- C08G18/4837—Polyethers containing oxyethylene units and other oxyalkylene units
- C08G18/4841—Polyethers containing oxyethylene units and other oxyalkylene units containing oxyethylene end groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0008—Foam properties flexible
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0041—Foam properties having specified density
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0083—Foam properties prepared using water as the sole blowing agent
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Organic Chemistry (AREA)
- Polymers & Plastics (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Epidemiology (AREA)
- Materials Engineering (AREA)
- Hematology (AREA)
- Dispersion Chemistry (AREA)
- Polyurethanes Or Polyureas (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
A hydrophilic polyurethane foam for use in first aid dressings which comprises residues from an aromatic isocyanate prepolymer and an aliphatic isocyanate prepolymer and in which at least one of said prepolymers contains residues from polyether polyol. A
process for the formation of the hydrophilic polyurethane and absorptive devices of hydrophilic polyurethane foam such as wound dressings and sanitary devices.
process for the formation of the hydrophilic polyurethane and absorptive devices of hydrophilic polyurethane foam such as wound dressings and sanitary devices.
Description
2 1 1 4 4 1 ~ PCI`/GB92/01527 POLYURETHANE FOAMS
The present invention relates to hydrophilic polyurethane foams, blends used to prepare these foams, absorptive devices co~prising the foams and methods for their preparation.
There have been several proposals to the use of hydrophilic polyur~thane foams, fcr example as an absorbent material, in hygienic and medical absorptive devices such as sanitary towels, tampons, diapers, incqntinence pads and wound dressings. Hydrophilic polyurethane foams, however, are usually more expensive than the conventional cellulosie absor~ent materials used in such devices and have there~ore not been ex~ensively used in commercial absorptive devices.
British Patent No. 1429711 (see also United States Patent Nos. 3Bl~618, 3812619 t 3874694, 388g417, 3928138, 3929574 and 4137200~ discloses a hydrophilic polyurethane foam formed by reacting with water an isocyanate capped polyoxyethylene glycol prepolymer.
It was found, however, that a large molar excess of wa~er was r quired to obtain satisfactory foams.
Removal of this excess water, for example, by drying, rendered these foams relatively expensive to manu~acture.
WO 93/W101 - 2 - PCr/GB92/01527 2114~11 British Patent No. 2188055 discloses hydrophilic polyurethane foams formed by reacting with water the reaction product of polyisocyanate which has a functionality of greater than 2 and polyalkylene glycol mono alkyl or alkaryl ether. These prepolymers require t~ be mixed with only relatively low a~ounts of water, ~hus obviating the need for an elaborate drying stage~
~he foams are therefore more econo~ical to manufacture than previously known hy~ropilic foa~s.
The reaction rates of aliphatic isocyanate based polyurethane foam systems tend to be ~ndesirably slow for commerical use unless high levels of ethylene oxide containing residues are incorporated into ~he reactive system.
The presence of high levels of such residues increases the linear swell value of the foa~ when hydra~ed. Whil~ this effect may not be del~terious for foa~ ptoducts such as ta~pons or sanitary towels, high linear swell will adver ely affect thin foam p~oducts such as wound dressings and in particular dressings such as first aid dressings, Such dressings need to be able ~o absorb aqueous materials such as wound exudate and to be produced ;
The present invention relates to hydrophilic polyurethane foams, blends used to prepare these foams, absorptive devices co~prising the foams and methods for their preparation.
There have been several proposals to the use of hydrophilic polyur~thane foams, fcr example as an absorbent material, in hygienic and medical absorptive devices such as sanitary towels, tampons, diapers, incqntinence pads and wound dressings. Hydrophilic polyurethane foams, however, are usually more expensive than the conventional cellulosie absor~ent materials used in such devices and have there~ore not been ex~ensively used in commercial absorptive devices.
British Patent No. 1429711 (see also United States Patent Nos. 3Bl~618, 3812619 t 3874694, 388g417, 3928138, 3929574 and 4137200~ discloses a hydrophilic polyurethane foam formed by reacting with water an isocyanate capped polyoxyethylene glycol prepolymer.
It was found, however, that a large molar excess of wa~er was r quired to obtain satisfactory foams.
Removal of this excess water, for example, by drying, rendered these foams relatively expensive to manu~acture.
WO 93/W101 - 2 - PCr/GB92/01527 2114~11 British Patent No. 2188055 discloses hydrophilic polyurethane foams formed by reacting with water the reaction product of polyisocyanate which has a functionality of greater than 2 and polyalkylene glycol mono alkyl or alkaryl ether. These prepolymers require t~ be mixed with only relatively low a~ounts of water, ~hus obviating the need for an elaborate drying stage~
~he foams are therefore more econo~ical to manufacture than previously known hy~ropilic foa~s.
The reaction rates of aliphatic isocyanate based polyurethane foam systems tend to be ~ndesirably slow for commerical use unless high levels of ethylene oxide containing residues are incorporated into ~he reactive system.
The presence of high levels of such residues increases the linear swell value of the foa~ when hydra~ed. Whil~ this effect may not be del~terious for foa~ ptoducts such as ta~pons or sanitary towels, high linear swell will adver ely affect thin foam p~oducts such as wound dressings and in particular dressings such as first aid dressings, Such dressings need to be able ~o absorb aqueous materials such as wound exudate and to be produced ;
- 3 - 2 1 1 ~ I 1 1 PCr/GB92/01527 quickly and economically to compare f-~ourably with conventional fa~ric and pad dressings.
The present invention seeks to ~-rovide a -~
polyurethane foam which is hydrophili- ~nd has good di~ensional sta~ility whe~ produced i~ thin flat sheets and which can be produ~ed rapidly and economically.
Accordingly the present inventi~n provides a polyurethane hydrophilic foam, suitab'e ~or u~,e as first aid dressing which and comprise residues of a aromatic isocyanate, of an aliphatic :socyanate, of a polyoxyalkylene monoether and of a pc:yoxyalkylene polyol such as a polyether polyol.
In another aspect the present i~.vention further provides an absorptive device which c~prises a hydrophilic polyurethane foam of the ~nvention. The absorptive device of the invention is preferably a medical or hygienic device such as a Yound dressing eg.
a first aid dre~sing~ sanitary towel, diaper, incontinence pad ta~pon, or th~ e.
In a further aspect the invention provides a process for preparing a hydrophilic ~lyurethane foam of the invention whi~h comprises bler.~ing at least one aromatic based prepolymer with at least one WO93~04101 ~ ~ 4 ~ PCT/GB92/01527 21 l 1~11 aliphatic based prepolymer. An aqueous phase is then added to effect the foaming reaction and the foam formed is allowed to set.
According to an embodiment of the present invention there is provided a hydrophilic polyurethane foam comprising resid~es of a first isocyanate prepolymer derived from a polyoxyalkylene mono ether and an aro~atic isocyanate containing at least two isocy~nate groups and residues of a second isocyanate prepolymer derived from a polyoxyalkylene mono ether and an aliphatic isocyanate containing at least two isocyanate g~oups and in which at least one of said isocyanate prepolymers contains residues fro~ a polyether polyol.
The present invention also p~ovides a hydrophilic polyurethane foam for~ed by blend~ng at least one of said aromatic isocyanate based prepoly~ers and at least one aliphatic isocya~ate based prepoly~ers and subsequently adding an aqeous phase to ea~alyse the foaming reaction wherein at least one of the prepolymers is additionally derived from a polyether polyol.
According to the process of the present invention, control over a wider ran~e of processing W093~04101 211 4 4 1 1 PCT/GB92/01527 variables and foam properties can be ~-hieved than was hitherto possib.~
Processing variables which may ~e controlled more readily than was previously possible :~clude efficiency of mixing and ease of dispensing, cre~ ti~e, rise time, gel time and cure time.
Foa~ properties which may be cc-trolled more ~;
.. readily according to the pro~ess of t~e invention include softness and resiliency, dens:ty, cell size and .
structure, water content and capacit~. linear swell on :~:
hydrat`ion and rate of wicking. :~
~ hese properties may be ~chieve~ by blending the prepolymers over a wide range of rati-s of the aromatic b~sed prepolymer to ~he aliphata~ bac~ prepolymer properties. Thus foams displaying e~^ellent water uptake, water ~apacity ~nd strength ~ve been found.
The foa~s also possess a low~r level ^f ex~ractables.
Furthermore they can be form~d in~o ~~in sheets which show excellen~ confsrMabil~ty.
S~itably the prepolymer blend s~ould contain at least lOw/w% of the solids weight of ~liphatic based prepolymer. Similarly it has been fc_nd that the blend should contain at least lOw/w% of th~ solids weight of WO93/~101 ` 211 4 41 1 - 6 - PCT/GB92/01527 aromatic based prepolymer. Aptly the ratio of aromatic isocyanate to aliphatic isocyanate prepolymers will be from 25-75 to 75:25 weight percent. ~ore aptly the ratio of prepolymers will be about 50:50 weight percent.
The hydrophilic polyurethane foa~s of the invention can be formed by mixing the blend with a stoichiometri~ amoun~ of water~ It is preferr~d, however, to mix the blend with a low ~olar exce~s af wa~er for example 10% by weight of water. It has been found that this low molar ex~ess of water can be easily absorb~d by the hydrophilic foa~.
Suitable polyoxyalkylene ~ono ethers for preparin~ the prepolymer co~ponents of the blend of the presen~ invention, may be polyoxyalkylene monoalkyl or monoalkaryl ethers. Prefera~ly the ~ono ethers are polyalkylene glycol monoethers.
The al~ylene ~oiety of the ~ono ethers ~ay contain l to 4 carbons~
Preferred polyalkylene glycol ~ono alkaryl ethers are those in w~ich the alkylene group is ethylene.
Suitable polyalkylene glycol mono alkaryl ethers WO93/~101 ~ 211 ~1;41 1 PCT/GB92/01527 ~
include those in which the a~yl moeity is phenyl.
Preferred ethers are those in which the alkyl moeity contains from 1 to 20 carbon atoms eg. octyl or nonyl.
Suitable polyalkylene qlycol mono alkyl ethers for forming the reaction product are those in which the alkyl group contains 1 to 20 carbon atoms. Aikylene favoured ethers are thos~ in which the alkyl group is a methyl group. Another class of preferred poly~lkylene glycol mono alkyl ethers are those in which the alkyl group contains 10 to 18 carbon atoms, eg. lauryl or cetyl~
Preferred polyalkylene glycol ~ono alkyl ethers are those in which the alkyle~ie grs~up is ethylene.
The polyalkylene glycol alkyl or alkaryl ether can suitably have an average ~olecular weight of 180 to 6000.
Apt e~her~ are polyethylene glycol ~ono lauryl ether~ haviny an average molecular weight of approxi~ately 1090 and 360 known 25 Brij 35 and ~rij 30 respectively, available from Hone~well Atlas and polyethylene glycol mono methyl ethers having an average molecular weight of approximately 500 and 5000 known as PEG monomethylethe~ ~olecular weight 550 and WO93/04101 , 211 9 ~ 1 1 PCT/GB92/01527 5000 respectively, available from Aldrich Chemicals.
Suitable polyethylene glycol ~ono nonyl phenyl ethers are commercially available under the Trade names Antarox C0-320 / Antarox Co-990, available f rom GAF
( Great ~ri tain ) Co . Ltd . Apt polyethylene glycol mono nonyl phenyl ethers t are Dowafax 9N6 and 9N20 having an average molecular wieght in the range of 400-500 and 1100-1200 respectively and av~ilable from K~l~ Greeft Ltd. Typically tbe ethylene oxide molecular weight can vary in the range 220 to 2200.
The polyethylene glycol ~ono al~yl or alkaryl ether used in the invention will nor~a}ly contain water. It is preferr~d, however, that the ether contains less than 1% by weight water, to li~it the number of urea groups formed in the reaction with the polyisocyanate during the prepolymer formul3tion.
The polye~her polyol residues present in at least one of the blend prepolymers, ~ay be derived from polyhydric alcohol~, alkylene polya~ines, ~lkylene amines, cyclic amines, amides and polycarboxylic acids.
In addition suitable polyols ~ay be derived from hydrophilic reactants. A particularly suitable hydrophilic reactant is ethylene oxide.
WO93/04101 ` 21 i 4 4 1 1PcT/GB92/ols27 Preferred polyether polyols are ~erived from ethylene oxide and aliphatic polyhydr_- alcohols.
Suitable alcohols may have from 2 to ~ carbon atoms eg.
ethylene glycol, pentaerythritol, prorvlene glycol, 2,3-butylene glycol, glycerol, 1,5-pe-:anediol and the like.
The polyether polyols may be derived from the polymerisation of ethylene oxide in t~e presence of the above mentioned di- or polyfunctional reactants.
Particularly suitable polyether ?olyols for the preparàtion of foams of the present i-~ention are polyether t~iols. Preferred polyethe: triols are polyoxypropylene lPPG) ether triols, ~d-capped with p~lyethylene oxide (PEG). Suitably t~- PEG may comprise 2 to 30w/w~ of the polyether ~riol. Typi~ally the PEG comprises 5 to 15w/w% of the -Q~yether.
Apt polyoxypropylene ether tric:s, end-capped with PEG have an aYerage ~olecular we~ght of 700 to 7000. Typically the PPG ether triols, end c~pped with PEG will have an average molecular we:ght in the range of 3000-3500 eg. Arcol 132 available -rom Arco Chemical Products Europe~
At least one of the blend prepc:ymers may further WO93/04101 211 4 4 1 1 1 o PCT/GB92/01527 be derived from a copolymer polyether triol d~rived from the polyether polyols described -erein. A
particularly preferred copolymer poly~ther is based on PPG and PEG blocks. Suitably the PEG may be present in the range of 40 to 75w/w of the copol~mer. More suitably the PEG may comprise 45-55w~%. Preferably the PEG comprises 45w/w% of the copol~mer. A preferred copolymer polyether is Voranol CP1421 which has an average molecular weight in the range of 3000-3500 and is supplied by Dow Chemicals Europe.
The ratio of triol equivalents :o mono ether equivalents may be varied to alter t~.~ processing variables and the foam properties. ~ has been found that suitably the ratio of triol equ~Jalents to mono ether equivalents is in the range of ~,3 1 to 10:1, more suitab}y from 1:1 to 5:1 and pre~erably about 3:1.
The isocyanates used for for~i~ the blend prepolymers will have a functionalit~ of at least 2.
Suitably both the aliphatic aro~atic isocyanates will have a functionality of le~s than ab~u~ 2.5.
Suitable aliphatic polyisocyana~es for use in the invention include 4,4'-dicyclohexyl nethane di-isocyanate (Desmodur W) which has a functionali~y of 2.0 and is available from Bayer A.G. ~nd hexamethylene W093/0410l 2 1 1 ~-4 1 1 di-isocyanate.
Suitable aromatic isocyanates f_- forming the blend prepolymers are polymeric methy:Gne di-isocyanates. Polymeric methylene ~-isocyanates comprise a mixture of 4,4'-diphenyl ~hane diisocyanates and one or more of poly~eric homologues.
Apt polymeric methylene di-isocyanates are known as suprasec VM 10, VM 20 and VM 50 available from ICI and have a functionality of 2.07, 2.13 an~ 2.49 respectively. Further aromatic isocyanates which may be used include toluene di-isocyanate, methylene-bis-(4-phenyl isocyanate), 3,3'-bitolylene-4,4'-di-is~cyanate, 1.4-phenylene di-isocyana~e, naphthalene-l,S-di-iso~yanate and the lilc~ .
A favoured blend for for~ing fo~s of the present inven~ion comprises an aliphatic base_ prepoly~Qer de r ived f rom polyoxyethylene glycol ~no-nonyl phenyl ether, a polyoxypropylene ether trioli end-capped with PEG; a copolymer poplyether triol and 4~4' dicyclohexyl meth~ne di-isocyana~e (~esmodur W~ ~he blend further comprises an aromatic based prepolymer derived f r~m polyoxyethylene gylcol mono-nonyl phe~yl ether, a polyoxypropylene ether triol, end-ca~_ed with PEG and a polymeric methylene di-isocyanate c-~prising a WO93/~101 21~14~ 12 - PCT/GB92/01~27 mixture of 4,4'-diphenyl methane di-isocyanate and one or more polymeric homologues.
In forming the prepolymers, the isocyanate and reactive hydrogen containing compound are present in an amount to ensure that the prepolymers contain an excess of isoycanate groups. Aptly the isocyanate ~o hydroxyl ratio ~NCO:OH) is at least 2:1. Suitably the ~CO:OH
ratio should be less than 6:l. Typifally the NCO:OH
ratio is in the range of 2.7:l and 4:l.
. The prepolymers employed in the invention contain an excess of isocyanate groups. Suit~bly they contain an excess of at least 2 w/w% NCO groups, more suitably upto l2~w/w excess NCO groups; Typicall~ the prepolymers contain an excess of 5 tc 7w/w% NCO groups.
Normally the mono ethers and pclyols will be pre-dried to a wa~er content of less than 1%.
The blend can be reacted with an aqueous phase to form a hydrophili~ polyurethane foa~ of the inventio~.
The hydrophilic polyurethane so formed will normally be a cross-linked hydrophilic polyureth~ne foam. The hydrophilicity of the foam is believed to be dependent on the oxyethylene groups. Varying the wei~ht % of oxyethylene groups in the constituents of the blend, WO 93/04101 2i~
can provide the hydrophilic polyurethane foams of the invention with a wide range of water absorption properties. Suitably the hydrophilic foam will absorb at lea~t 5% by weight of its weight of water. The water absorption of the hydrophilic polyurethane foams aptly ranqe from 25% to 95% by weight of polym~r.
Preferred hydrophilic polyurethane foams of the invention, however, have a water absorption of 50% to 92% by weight of polymer.
The water absorption of the foa~ is determined by wei~hing a lcm cube of the foam, then immersing the foam in water (at 20C) for ~4 hours, removing excess water by lightly blotting the foam with absorbent paper and then re-weighing the foam cube. The water absorption of the foam (% by weight) can then be calculated as weiqht of wet foaml q) - wei~ht of_dry_foam (~_x 100 weight of wet foa~
The hydrophilic polyureth~ne foa~ of the invention will normally be an open cell foam. The open cell foam can suitably have a density of 20 to 350 Rg/m3 and can preferably have a density of 4 to 150Rg/m3.
WO93tO4101 21 l 4 ~ 14 - PCT/GR92/01527 The hydrophilic polyurethane f~æn can be in a sheet, moulded or particulate form.
The hydrophilic polyurethane foa~s of the invention can be used in absorptive devices for example as an absorbent component thereof.
If desired, the prepolymer forming reaction may be catalysed. Suitable catalysts inc~ude Dioctyl tin dilaurate (Metatin 812 ES ); dioctyl t rl mercapt.ide ester (Metatin 813 and Metatin 713); cibutyl tin dilaurate (T-12); stannous octate (T -~ and Bismuth neodecanoate (Coscat 83). Suitably t~.~ catalysts may be added in the range o f O . 5 to O . OOl~w %.
Suitably the a~ueous phase may :~nt~in a catalyst to increase the rate of reaction.
It has been found that a suitab'e amount of water required to be added to the prepoly~e~ blend can be the s~oichiometric amount of water needed to react with the NC~ groups in the prepolymers. ~ is pre~erred, however, in order to o~tain a homogen~us mixture of water and prepolymers to use up ~o 12~ eg. 4 to 10% by weight of water and preferably 5% by ~eight water in the process.
A suitable catalyst for the reaction is an alkali metal carbonate such as potassium carbonate which can be present in amounts of 0~5 to 1.5~ by weight of the blend.
In the process of the in~ention water or an aqueous solution will normally be provided in liquid form which is mixed and reacted with the prepolymer blend. The water in the process, however, can also be provided by a material such as a metal salt hy~drate which releases water in liquid or vapour ~orm when heated. Suitable metal hydrates for use in the invention include Na2B40~.10H20, ~a2 SO4 . 1OH2 0, Na~SiO3.9H20 and M~SO4.7H20 which is preferred. In the process the metal salt hydrate which is preferably in particulate form is mixed into the prepolymer blend.
The mixture can then be heated to a suitable temperature to release the water for reaction with the prepolymer blend.
The foam can be formed into a sheet or a desired shape by casting the foaming mixture into a release carrier or into a shaped mould and allowing the mixture to rise and set 4 The foams produced by the process of the invention can then be incorporated into absorptive WO93/~101 211 ~ 41 1 - 16 - PCT/GB92/01527 devices using conventional methods. -n particular the hydrophilic foams of the present inver.~ion may be used in the preparation of first aid dressings sinee they can be used to form thin flexible and onformable sheets which are ideally suited for ~a~ing such dressings.
Aptly the polyurethane foam co~position of the invention may cast into first aid dressings, for ~:
example as disclosed in WO91/01706 and WO91/01707. ~
Suitably su~h dressin~s may be cast to thi~knesses of ~:
O.5.to 20mm, more aptly fro~ 0.75 to 4~m.
The invention will now be illustrated by referen~e to the following example:
W0 93/04101 _ 17 ~ L PCI /GB92/01527 ALIPHATIC PREPOLYMEX FORMULATION
Polyoxypropylene (PP~) ether triol, 2 equiv.
polyethylene oxide (PEG) end-capped lArcol 1132) Polyoxyethylene mono-nonyl phenyl 1 equiv.
ether (Dowfax 9N20) Copolymer polyether triol (Voranol CP 1421) 1 equiv.
The present invention seeks to ~-rovide a -~
polyurethane foam which is hydrophili- ~nd has good di~ensional sta~ility whe~ produced i~ thin flat sheets and which can be produ~ed rapidly and economically.
Accordingly the present inventi~n provides a polyurethane hydrophilic foam, suitab'e ~or u~,e as first aid dressing which and comprise residues of a aromatic isocyanate, of an aliphatic :socyanate, of a polyoxyalkylene monoether and of a pc:yoxyalkylene polyol such as a polyether polyol.
In another aspect the present i~.vention further provides an absorptive device which c~prises a hydrophilic polyurethane foam of the ~nvention. The absorptive device of the invention is preferably a medical or hygienic device such as a Yound dressing eg.
a first aid dre~sing~ sanitary towel, diaper, incontinence pad ta~pon, or th~ e.
In a further aspect the invention provides a process for preparing a hydrophilic ~lyurethane foam of the invention whi~h comprises bler.~ing at least one aromatic based prepolymer with at least one WO93~04101 ~ ~ 4 ~ PCT/GB92/01527 21 l 1~11 aliphatic based prepolymer. An aqueous phase is then added to effect the foaming reaction and the foam formed is allowed to set.
According to an embodiment of the present invention there is provided a hydrophilic polyurethane foam comprising resid~es of a first isocyanate prepolymer derived from a polyoxyalkylene mono ether and an aro~atic isocyanate containing at least two isocy~nate groups and residues of a second isocyanate prepolymer derived from a polyoxyalkylene mono ether and an aliphatic isocyanate containing at least two isocyanate g~oups and in which at least one of said isocyanate prepolymers contains residues fro~ a polyether polyol.
The present invention also p~ovides a hydrophilic polyurethane foam for~ed by blend~ng at least one of said aromatic isocyanate based prepoly~ers and at least one aliphatic isocya~ate based prepoly~ers and subsequently adding an aqeous phase to ea~alyse the foaming reaction wherein at least one of the prepolymers is additionally derived from a polyether polyol.
According to the process of the present invention, control over a wider ran~e of processing W093~04101 211 4 4 1 1 PCT/GB92/01527 variables and foam properties can be ~-hieved than was hitherto possib.~
Processing variables which may ~e controlled more readily than was previously possible :~clude efficiency of mixing and ease of dispensing, cre~ ti~e, rise time, gel time and cure time.
Foa~ properties which may be cc-trolled more ~;
.. readily according to the pro~ess of t~e invention include softness and resiliency, dens:ty, cell size and .
structure, water content and capacit~. linear swell on :~:
hydrat`ion and rate of wicking. :~
~ hese properties may be ~chieve~ by blending the prepolymers over a wide range of rati-s of the aromatic b~sed prepolymer to ~he aliphata~ bac~ prepolymer properties. Thus foams displaying e~^ellent water uptake, water ~apacity ~nd strength ~ve been found.
The foa~s also possess a low~r level ^f ex~ractables.
Furthermore they can be form~d in~o ~~in sheets which show excellen~ confsrMabil~ty.
S~itably the prepolymer blend s~ould contain at least lOw/w% of the solids weight of ~liphatic based prepolymer. Similarly it has been fc_nd that the blend should contain at least lOw/w% of th~ solids weight of WO93/~101 ` 211 4 41 1 - 6 - PCT/GB92/01527 aromatic based prepolymer. Aptly the ratio of aromatic isocyanate to aliphatic isocyanate prepolymers will be from 25-75 to 75:25 weight percent. ~ore aptly the ratio of prepolymers will be about 50:50 weight percent.
The hydrophilic polyurethane foa~s of the invention can be formed by mixing the blend with a stoichiometri~ amoun~ of water~ It is preferr~d, however, to mix the blend with a low ~olar exce~s af wa~er for example 10% by weight of water. It has been found that this low molar ex~ess of water can be easily absorb~d by the hydrophilic foa~.
Suitable polyoxyalkylene ~ono ethers for preparin~ the prepolymer co~ponents of the blend of the presen~ invention, may be polyoxyalkylene monoalkyl or monoalkaryl ethers. Prefera~ly the ~ono ethers are polyalkylene glycol monoethers.
The al~ylene ~oiety of the ~ono ethers ~ay contain l to 4 carbons~
Preferred polyalkylene glycol ~ono alkaryl ethers are those in w~ich the alkylene group is ethylene.
Suitable polyalkylene glycol mono alkaryl ethers WO93/~101 ~ 211 ~1;41 1 PCT/GB92/01527 ~
include those in which the a~yl moeity is phenyl.
Preferred ethers are those in which the alkyl moeity contains from 1 to 20 carbon atoms eg. octyl or nonyl.
Suitable polyalkylene qlycol mono alkyl ethers for forming the reaction product are those in which the alkyl group contains 1 to 20 carbon atoms. Aikylene favoured ethers are thos~ in which the alkyl group is a methyl group. Another class of preferred poly~lkylene glycol mono alkyl ethers are those in which the alkyl group contains 10 to 18 carbon atoms, eg. lauryl or cetyl~
Preferred polyalkylene glycol ~ono alkyl ethers are those in which the alkyle~ie grs~up is ethylene.
The polyalkylene glycol alkyl or alkaryl ether can suitably have an average ~olecular weight of 180 to 6000.
Apt e~her~ are polyethylene glycol ~ono lauryl ether~ haviny an average molecular weight of approxi~ately 1090 and 360 known 25 Brij 35 and ~rij 30 respectively, available from Hone~well Atlas and polyethylene glycol mono methyl ethers having an average molecular weight of approximately 500 and 5000 known as PEG monomethylethe~ ~olecular weight 550 and WO93/04101 , 211 9 ~ 1 1 PCT/GB92/01527 5000 respectively, available from Aldrich Chemicals.
Suitable polyethylene glycol ~ono nonyl phenyl ethers are commercially available under the Trade names Antarox C0-320 / Antarox Co-990, available f rom GAF
( Great ~ri tain ) Co . Ltd . Apt polyethylene glycol mono nonyl phenyl ethers t are Dowafax 9N6 and 9N20 having an average molecular wieght in the range of 400-500 and 1100-1200 respectively and av~ilable from K~l~ Greeft Ltd. Typically tbe ethylene oxide molecular weight can vary in the range 220 to 2200.
The polyethylene glycol ~ono al~yl or alkaryl ether used in the invention will nor~a}ly contain water. It is preferr~d, however, that the ether contains less than 1% by weight water, to li~it the number of urea groups formed in the reaction with the polyisocyanate during the prepolymer formul3tion.
The polye~her polyol residues present in at least one of the blend prepolymers, ~ay be derived from polyhydric alcohol~, alkylene polya~ines, ~lkylene amines, cyclic amines, amides and polycarboxylic acids.
In addition suitable polyols ~ay be derived from hydrophilic reactants. A particularly suitable hydrophilic reactant is ethylene oxide.
WO93/04101 ` 21 i 4 4 1 1PcT/GB92/ols27 Preferred polyether polyols are ~erived from ethylene oxide and aliphatic polyhydr_- alcohols.
Suitable alcohols may have from 2 to ~ carbon atoms eg.
ethylene glycol, pentaerythritol, prorvlene glycol, 2,3-butylene glycol, glycerol, 1,5-pe-:anediol and the like.
The polyether polyols may be derived from the polymerisation of ethylene oxide in t~e presence of the above mentioned di- or polyfunctional reactants.
Particularly suitable polyether ?olyols for the preparàtion of foams of the present i-~ention are polyether t~iols. Preferred polyethe: triols are polyoxypropylene lPPG) ether triols, ~d-capped with p~lyethylene oxide (PEG). Suitably t~- PEG may comprise 2 to 30w/w~ of the polyether ~riol. Typi~ally the PEG comprises 5 to 15w/w% of the -Q~yether.
Apt polyoxypropylene ether tric:s, end-capped with PEG have an aYerage ~olecular we~ght of 700 to 7000. Typically the PPG ether triols, end c~pped with PEG will have an average molecular we:ght in the range of 3000-3500 eg. Arcol 132 available -rom Arco Chemical Products Europe~
At least one of the blend prepc:ymers may further WO93/04101 211 4 4 1 1 1 o PCT/GB92/01527 be derived from a copolymer polyether triol d~rived from the polyether polyols described -erein. A
particularly preferred copolymer poly~ther is based on PPG and PEG blocks. Suitably the PEG may be present in the range of 40 to 75w/w of the copol~mer. More suitably the PEG may comprise 45-55w~%. Preferably the PEG comprises 45w/w% of the copol~mer. A preferred copolymer polyether is Voranol CP1421 which has an average molecular weight in the range of 3000-3500 and is supplied by Dow Chemicals Europe.
The ratio of triol equivalents :o mono ether equivalents may be varied to alter t~.~ processing variables and the foam properties. ~ has been found that suitably the ratio of triol equ~Jalents to mono ether equivalents is in the range of ~,3 1 to 10:1, more suitab}y from 1:1 to 5:1 and pre~erably about 3:1.
The isocyanates used for for~i~ the blend prepolymers will have a functionalit~ of at least 2.
Suitably both the aliphatic aro~atic isocyanates will have a functionality of le~s than ab~u~ 2.5.
Suitable aliphatic polyisocyana~es for use in the invention include 4,4'-dicyclohexyl nethane di-isocyanate (Desmodur W) which has a functionali~y of 2.0 and is available from Bayer A.G. ~nd hexamethylene W093/0410l 2 1 1 ~-4 1 1 di-isocyanate.
Suitable aromatic isocyanates f_- forming the blend prepolymers are polymeric methy:Gne di-isocyanates. Polymeric methylene ~-isocyanates comprise a mixture of 4,4'-diphenyl ~hane diisocyanates and one or more of poly~eric homologues.
Apt polymeric methylene di-isocyanates are known as suprasec VM 10, VM 20 and VM 50 available from ICI and have a functionality of 2.07, 2.13 an~ 2.49 respectively. Further aromatic isocyanates which may be used include toluene di-isocyanate, methylene-bis-(4-phenyl isocyanate), 3,3'-bitolylene-4,4'-di-is~cyanate, 1.4-phenylene di-isocyana~e, naphthalene-l,S-di-iso~yanate and the lilc~ .
A favoured blend for for~ing fo~s of the present inven~ion comprises an aliphatic base_ prepoly~Qer de r ived f rom polyoxyethylene glycol ~no-nonyl phenyl ether, a polyoxypropylene ether trioli end-capped with PEG; a copolymer poplyether triol and 4~4' dicyclohexyl meth~ne di-isocyana~e (~esmodur W~ ~he blend further comprises an aromatic based prepolymer derived f r~m polyoxyethylene gylcol mono-nonyl phe~yl ether, a polyoxypropylene ether triol, end-ca~_ed with PEG and a polymeric methylene di-isocyanate c-~prising a WO93/~101 21~14~ 12 - PCT/GB92/01~27 mixture of 4,4'-diphenyl methane di-isocyanate and one or more polymeric homologues.
In forming the prepolymers, the isocyanate and reactive hydrogen containing compound are present in an amount to ensure that the prepolymers contain an excess of isoycanate groups. Aptly the isocyanate ~o hydroxyl ratio ~NCO:OH) is at least 2:1. Suitably the ~CO:OH
ratio should be less than 6:l. Typifally the NCO:OH
ratio is in the range of 2.7:l and 4:l.
. The prepolymers employed in the invention contain an excess of isocyanate groups. Suit~bly they contain an excess of at least 2 w/w% NCO groups, more suitably upto l2~w/w excess NCO groups; Typicall~ the prepolymers contain an excess of 5 tc 7w/w% NCO groups.
Normally the mono ethers and pclyols will be pre-dried to a wa~er content of less than 1%.
The blend can be reacted with an aqueous phase to form a hydrophili~ polyurethane foa~ of the inventio~.
The hydrophilic polyurethane so formed will normally be a cross-linked hydrophilic polyureth~ne foam. The hydrophilicity of the foam is believed to be dependent on the oxyethylene groups. Varying the wei~ht % of oxyethylene groups in the constituents of the blend, WO 93/04101 2i~
can provide the hydrophilic polyurethane foams of the invention with a wide range of water absorption properties. Suitably the hydrophilic foam will absorb at lea~t 5% by weight of its weight of water. The water absorption of the hydrophilic polyurethane foams aptly ranqe from 25% to 95% by weight of polym~r.
Preferred hydrophilic polyurethane foams of the invention, however, have a water absorption of 50% to 92% by weight of polymer.
The water absorption of the foa~ is determined by wei~hing a lcm cube of the foam, then immersing the foam in water (at 20C) for ~4 hours, removing excess water by lightly blotting the foam with absorbent paper and then re-weighing the foam cube. The water absorption of the foam (% by weight) can then be calculated as weiqht of wet foaml q) - wei~ht of_dry_foam (~_x 100 weight of wet foa~
The hydrophilic polyureth~ne foa~ of the invention will normally be an open cell foam. The open cell foam can suitably have a density of 20 to 350 Rg/m3 and can preferably have a density of 4 to 150Rg/m3.
WO93tO4101 21 l 4 ~ 14 - PCT/GR92/01527 The hydrophilic polyurethane f~æn can be in a sheet, moulded or particulate form.
The hydrophilic polyurethane foa~s of the invention can be used in absorptive devices for example as an absorbent component thereof.
If desired, the prepolymer forming reaction may be catalysed. Suitable catalysts inc~ude Dioctyl tin dilaurate (Metatin 812 ES ); dioctyl t rl mercapt.ide ester (Metatin 813 and Metatin 713); cibutyl tin dilaurate (T-12); stannous octate (T -~ and Bismuth neodecanoate (Coscat 83). Suitably t~.~ catalysts may be added in the range o f O . 5 to O . OOl~w %.
Suitably the a~ueous phase may :~nt~in a catalyst to increase the rate of reaction.
It has been found that a suitab'e amount of water required to be added to the prepoly~e~ blend can be the s~oichiometric amount of water needed to react with the NC~ groups in the prepolymers. ~ is pre~erred, however, in order to o~tain a homogen~us mixture of water and prepolymers to use up ~o 12~ eg. 4 to 10% by weight of water and preferably 5% by ~eight water in the process.
A suitable catalyst for the reaction is an alkali metal carbonate such as potassium carbonate which can be present in amounts of 0~5 to 1.5~ by weight of the blend.
In the process of the in~ention water or an aqueous solution will normally be provided in liquid form which is mixed and reacted with the prepolymer blend. The water in the process, however, can also be provided by a material such as a metal salt hy~drate which releases water in liquid or vapour ~orm when heated. Suitable metal hydrates for use in the invention include Na2B40~.10H20, ~a2 SO4 . 1OH2 0, Na~SiO3.9H20 and M~SO4.7H20 which is preferred. In the process the metal salt hydrate which is preferably in particulate form is mixed into the prepolymer blend.
The mixture can then be heated to a suitable temperature to release the water for reaction with the prepolymer blend.
The foam can be formed into a sheet or a desired shape by casting the foaming mixture into a release carrier or into a shaped mould and allowing the mixture to rise and set 4 The foams produced by the process of the invention can then be incorporated into absorptive WO93/~101 211 ~ 41 1 - 16 - PCT/GB92/01527 devices using conventional methods. -n particular the hydrophilic foams of the present inver.~ion may be used in the preparation of first aid dressings sinee they can be used to form thin flexible and onformable sheets which are ideally suited for ~a~ing such dressings.
Aptly the polyurethane foam co~position of the invention may cast into first aid dressings, for ~:
example as disclosed in WO91/01706 and WO91/01707. ~
Suitably su~h dressin~s may be cast to thi~knesses of ~:
O.5.to 20mm, more aptly fro~ 0.75 to 4~m.
The invention will now be illustrated by referen~e to the following example:
W0 93/04101 _ 17 ~ L PCI /GB92/01527 ALIPHATIC PREPOLYMEX FORMULATION
Polyoxypropylene (PP~) ether triol, 2 equiv.
polyethylene oxide (PEG) end-capped lArcol 1132) Polyoxyethylene mono-nonyl phenyl 1 equiv.
ether (Dowfax 9N20) Copolymer polyether triol (Voranol CP 1421) 1 equiv.
4,4'-dicyclohexylmethane di-isocyanate (Desmodur W~ to give an NCO:OH ratio of 3.0:1.
Tin catalyst lMetatin 812ES, ~cima Chemicals L~d) 0.05 w~w%
.
AROMATIC PR POLYM R_FORMU~ATION
Arcol 1132 2 equiv Polyoxyethylene ~ono-n~nyl phenyl ether l equiv~
lDowfax 9N6~
Methylene diphenyl di-isocyanate (VM10) to sive an NCO:O~ ratio of 3.5:1 Tin catalyst (Metatin 812ES) 0.01 w/w~
.:, . .
, . . .
WO93/~101 - 18 - PCT/GB92/01527 2111~11 The aliphatie prepolymer is syn~esised ~y first heating the triols and mono ethe~ in an oven at 60~C to melt them. The melted triols and monc ether are then added to a 700ml flange flask followe~ by the d,-isocyanate. The flask is fitted ~ith an ai r-driven anchor stirrer, a lid, a dry nitrogen blanket and placed in a water bath at 60~C. The co~ponents are stirred vigourously until homogenous. The tin catlayst is added via a diposable syringe, whi'e the contents o the flask are being stirred continuously. The water bath is adjusted to 90C and the reac~ion is allowed to continue for 60 minutes until complet ~n, as indicated by the subsiding exotherm. After ~o~letion, the prepolymer is poured while still war~ into an air-tight jar.
.. .
The aromatic prepolymer is for~d by followin~
the sa~e steps as indicated above for preparation of the aliphatic prepoly~er, except that after sdjusting the water bath t~ gOC, the reaction is all~wed to proceed for 30 rathe~ than 60 ~inute~.
The aliphatic and aromatic prepoly~ers are then blended~ When a homogenous prepolyme~ blend is obtained the aqueous phase is added t~ effect foaming.
.. ... . , ~ .........
2114 ~ ~ PCT/GB92/01527 WO93/~101 The foam formed possesses all the properties discussed a~ove which render it ideally suited for use in absorptive devices, particularly first-aid dressings.
Tin catalyst lMetatin 812ES, ~cima Chemicals L~d) 0.05 w~w%
.
AROMATIC PR POLYM R_FORMU~ATION
Arcol 1132 2 equiv Polyoxyethylene ~ono-n~nyl phenyl ether l equiv~
lDowfax 9N6~
Methylene diphenyl di-isocyanate (VM10) to sive an NCO:O~ ratio of 3.5:1 Tin catalyst (Metatin 812ES) 0.01 w/w~
.:, . .
, . . .
WO93/~101 - 18 - PCT/GB92/01527 2111~11 The aliphatie prepolymer is syn~esised ~y first heating the triols and mono ethe~ in an oven at 60~C to melt them. The melted triols and monc ether are then added to a 700ml flange flask followe~ by the d,-isocyanate. The flask is fitted ~ith an ai r-driven anchor stirrer, a lid, a dry nitrogen blanket and placed in a water bath at 60~C. The co~ponents are stirred vigourously until homogenous. The tin catlayst is added via a diposable syringe, whi'e the contents o the flask are being stirred continuously. The water bath is adjusted to 90C and the reac~ion is allowed to continue for 60 minutes until complet ~n, as indicated by the subsiding exotherm. After ~o~letion, the prepolymer is poured while still war~ into an air-tight jar.
.. .
The aromatic prepolymer is for~d by followin~
the sa~e steps as indicated above for preparation of the aliphatic prepoly~er, except that after sdjusting the water bath t~ gOC, the reaction is all~wed to proceed for 30 rathe~ than 60 ~inute~.
The aliphatic and aromatic prepoly~ers are then blended~ When a homogenous prepolyme~ blend is obtained the aqueous phase is added t~ effect foaming.
.. ... . , ~ .........
2114 ~ ~ PCT/GB92/01527 WO93/~101 The foam formed possesses all the properties discussed a~ove which render it ideally suited for use in absorptive devices, particularly first-aid dressings.
Claims (25)
1. A hydrophilic polyurethane foam, which comprises residues of an aromatic isocyanate, an aliphatic isocyanate, a polyoxyalkylene mono ether and a polyether polyol.
2. A hydrophilic polyurethane foam, which comprises residues of a first isocyanate prepolymer derived from a polyoxyalkylene mono ether and an aromatic isocyanate containing at least two isocyanate groups and residues of a second isocyanate prepolymer derived from a polyoxyalkylene mono ether and an aliphatic isocyanate containing at least two isocyanate groups and in which at least one of said prepolymers contains residues from a polyether polyol.
3. A foam according to claim 1, wherein the polyether polyol is a polyoxyalkylene polyol.
4. A foam according to any of claims 1 to 3, wherein the polyether polyol residues in at least one of the blend prepolymers is derived from hydrophilic reactants.
5. A foam according to any of claims 1 to 4, wherein the polyol residues are polyether triols.
6. A foam according to claim 5, wherein the polyether triol is polyoxypropylene (PPG) ether triols, end-capped with polyethylene oxide (PEG).
7. A foam according to claim 6, wherein the PEG
comprises 2 to 30 w/w% of polyether triol.
comprises 2 to 30 w/w% of polyether triol.
8. A foam according to claim 6 or claim 7, wherein the PPG either triol, end-capped with PEG has a molecular weight in the range of 700 to 7000.
9. A foam according to any of claims 6 to 8, wherein the PEG is present in the range of 40 to 75 w/w% of copolymer.
10. A foam according to any of the preceding claims, wherein the ratio of polyol equivalents to mono ether equivalents is in the range of 1.3:1 to 10:1.
11. A foam according to any of the preceding claims, wherein the isocyanates have a functionality of at least 2.
12. A foam according to any one of claims 2 to 11, wherein the aliphatic based prepolymer is derived from polyoxyethylene glycol mono-nonyl phenyl ether, a polyoxypropylene ether triol, end-capped with PEG, a copolymer polyether triol and an aliphatic di-isocyanate.
13. A foam according to claims 2 to 12, wherein the aromatic based prepolymer is derived from a polyoxyethylene glycol mono-nonyl phenyl ether, a polyoxypropylene ether triol, end-capped with PEG and a polyermic methylene di-isocyanate.
..
..
14. A foam according to any of claims 2 to 13, wherein the prepolymers contain an excess of isocyanate groups.
15. A foam according to claim 14, wherein the prepolymers conkain an excess of at least 2 w/w% NCO
groups.
groups.
16. A process for the preparation of a hydrophilic polyurethane foam which comprises reacting at least one of each of an aromatic isocyanate, an aliphatic isocyanate, a polyoxyalkylene mono ether and a PCT/GB92/0152?
polyether polyol to form a foam precursor and thereafter foaming the precursor.
polyether polyol to form a foam precursor and thereafter foaming the precursor.
17. A process according to claim 16, in which the foam precursor is a single prepolymer derived from an aromatic isocyanate, an aliphatic isocyanate, a polyoxyalkylene mono ether and a polyether polyol.
18. A process according to claim 16, in which the foam precursor comprises a mixture of isocyanate prepolymers derived from the aromatic isocyanate, the aliphatic isocyanate, the polyoxyalkylene mono ether and the polyether polyol.
19. A process for the preparation of hydrophilic polyurethane foam comprising the steps of:-- blending at least one aromatic-based, isocyanate based prepolymer and at least one aliphatic-based, isocyanate based prepolymer.
- adding an aqueous foaming phase; wherein at least one of the prepolymers is derived from polyoxyalkylene polyol.
- adding an aqueous foaming phase; wherein at least one of the prepolymers is derived from polyoxyalkylene polyol.
20. A process according to claim 19, wherein the prepolymer blend contains at least 10 w/w% of solids weight of the first isocyanate based prepolymer and 10 w/w% of solids weight of the second isocyanate based prepolymer.
21. A process according to claim 19 or 20, wherein the ratio of the first isocyanate based prepolymer to the second isocyanate prepolymer is between 25:75 to 75:25 weight per cent.
22. Process according to any of claims 19 to 21, wherein the prepolymer blend is mixed with 10% by weight of water.
23. A foam produced by the process as claimed in any of claims 16 to 22 and having a composition as claimed in any of claims 1 to 15.
24. An absorptive device comprising a foam as claimed in any of claims 1 to 15.
25. An absorptive device according to claim 24 in the form of a first aid dressing.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9117913.5 | 1991-08-20 | ||
| GB919117913A GB9117913D0 (en) | 1991-08-20 | 1991-08-20 | Polyurethane foams |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2114411A1 true CA2114411A1 (en) | 1993-03-04 |
Family
ID=10700213
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002114411A Abandoned CA2114411A1 (en) | 1991-08-20 | 1992-08-19 | Polyurethane foams |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0599932A1 (en) |
| JP (1) | JPH06510312A (en) |
| AU (1) | AU656997B2 (en) |
| CA (1) | CA2114411A1 (en) |
| GB (2) | GB9117913D0 (en) |
| MX (1) | MX9204833A (en) |
| WO (1) | WO1993004101A1 (en) |
| ZA (1) | ZA926233B (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4328190A1 (en) * | 1993-08-23 | 1995-03-02 | Beiersdorf Ag | Wound care articles with selective absorbency |
| ATE485323T1 (en) | 2001-05-21 | 2010-11-15 | Huntsman Int Llc | VERY SOFT POLYURETHANE ELASTOMER |
| WO2008112712A1 (en) | 2007-03-13 | 2008-09-18 | Avery Dennison Corporation | Foam compositions and articles including cyclodextrin crosslinked with polyurethane prepolymer and preparation thereof |
| EP2289959A1 (en) * | 2009-08-29 | 2011-03-02 | Bayer Material Science AG | Hydrophilic aliphatic polyurethane foams |
| KR20120082407A (en) * | 2009-09-18 | 2012-07-23 | 아사히 가라스 가부시키가이샤 | Process for production of flexible polyurethane foam |
| FR2974004B1 (en) | 2011-04-15 | 2014-05-02 | Urgo Lab | HYDROCELLULAR ABSORBENT DRESSING, ITS USES FOR THE TREATMENT OF CHRONIC AND ACUTE WOUNDS |
| FR2974005B1 (en) | 2011-04-15 | 2014-05-02 | Urgo Lab | THIN ABSORBENT THIN ADHESIVE DRESSING, ITS USES FOR THE TREATMENT OF CHRONIC WOUNDS |
| EP3508182A1 (en) | 2011-07-14 | 2019-07-10 | Smith & Nephew PLC | Wound dressing and method of treatment |
| FR3003463B1 (en) | 2013-03-20 | 2015-04-10 | Urgo Lab | DRESSING HAVING AN ADHESIVE PERIPHERAL EDGE WITH AN INUTED ROUND |
| US9422394B2 (en) | 2013-06-28 | 2016-08-23 | Sabic Global Technologies B.V. | Thermoplastic polyurethane and associated method and article |
| US9169368B2 (en) | 2013-07-30 | 2015-10-27 | Sabic Global Technologies B.V. | Rigid foam and associated article |
| US9266997B2 (en) * | 2013-09-20 | 2016-02-23 | Sabic Global Technologies B.V. | Polyurethane foam and associated method and article |
| FR3056100B1 (en) | 2016-09-20 | 2019-07-05 | Urgo Recherche Innovation Et Developpement | ABSORBENT DRESSING COMPRISING A HYDRODELITABLE SUPERABSORBENT NON-WOVEN |
| GB201818824D0 (en) | 2018-11-19 | 2019-01-02 | Smith & Nephew | Absorbent yarn |
| GB201818829D0 (en) | 2018-11-19 | 2019-01-02 | Smith & Nephew | Absorbent component |
| GB201912071D0 (en) | 2019-08-22 | 2019-10-09 | Smith & Nephew | Wound dressing |
| GB201912076D0 (en) | 2019-08-22 | 2019-10-09 | Smith & Nephew | Absorbent component |
| FR3133122B1 (en) | 2022-03-03 | 2024-03-01 | Urgo Rech Innovation Et Developpement | Modular dressing |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH433740A (en) * | 1964-10-14 | 1967-04-15 | Elekal Societe Anonyme | Process for manufacturing a hydrophilic polyurethane foam |
| US3457203A (en) * | 1966-04-25 | 1969-07-22 | Olin Mathieson | Hydrophilic polyurethane foams and a process for preparing them |
| US4292412A (en) * | 1980-01-16 | 1981-09-29 | W. R. Grace & Co. | Hydrophilic, fabric softener foam compositions and method of making |
| US4439553A (en) * | 1983-01-17 | 1984-03-27 | W. R. Grace & Co. | High molecular weight aromatic amine scavengers and method of use |
| DE3778361D1 (en) * | 1987-07-15 | 1992-05-21 | Proni Creations Inc | A FORCE CONCENTRATING UNIFIED PIPE CONNECTION. |
| ATE65528T1 (en) * | 1987-07-17 | 1991-08-15 | Smith & Nephew | HYDROPHILIC POLYURETHANE FOAM. |
-
1991
- 1991-08-20 GB GB919117913A patent/GB9117913D0/en active Pending
-
1992
- 1992-08-19 EP EP92917631A patent/EP0599932A1/en not_active Withdrawn
- 1992-08-19 CA CA002114411A patent/CA2114411A1/en not_active Abandoned
- 1992-08-19 AU AU24404/92A patent/AU656997B2/en not_active Ceased
- 1992-08-19 WO PCT/GB1992/001527 patent/WO1993004101A1/en not_active Application Discontinuation
- 1992-08-19 JP JP5504197A patent/JPH06510312A/en active Pending
- 1992-08-19 GB GB9400982A patent/GB2273296B/en not_active Expired - Fee Related
- 1992-08-19 ZA ZA926233A patent/ZA926233B/en unknown
- 1992-08-20 MX MX9204833A patent/MX9204833A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| AU2440492A (en) | 1993-03-16 |
| GB2273296B (en) | 1995-05-24 |
| GB9117913D0 (en) | 1991-10-09 |
| GB2273296A (en) | 1994-06-15 |
| AU656997B2 (en) | 1995-02-23 |
| WO1993004101A1 (en) | 1993-03-04 |
| EP0599932A1 (en) | 1994-06-08 |
| MX9204833A (en) | 1993-03-01 |
| GB9400982D0 (en) | 1994-03-16 |
| JPH06510312A (en) | 1994-11-17 |
| ZA926233B (en) | 1994-03-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |