CA2142373A1 - Polymer products - Google Patents
Polymer productsInfo
- Publication number
- CA2142373A1 CA2142373A1 CA 2142373 CA2142373A CA2142373A1 CA 2142373 A1 CA2142373 A1 CA 2142373A1 CA 2142373 CA2142373 CA 2142373 CA 2142373 A CA2142373 A CA 2142373A CA 2142373 A1 CA2142373 A1 CA 2142373A1
- Authority
- CA
- Canada
- Prior art keywords
- composition
- precursor
- compositions
- hydrophilic polyurethane
- polyurethane
- 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
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
- C09D175/04—Polyurethanes
-
- 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
- C08G2290/00—Compositions for creating anti-fogging
Abstract
Polymer and polymerisable composition suitable for use as anti-fogging materials comprise blends of hydrophilic polyure-thane together with polymers preferably derived from monomers or oligomers containing ethylenic unsaturation or with curable polymer precursors which have acrylic unsaturation.
Description
~ W094/04587` 2 1 12 ~ 7 ~ PCT/GB93/017~
Pol~mer ~roducts .
~ his invention rela~es ~o polymer composl~ions and` more particularly tO compositions for use in the manufacture of transparent or reflective articles.
The use of polymer films for improving the Li~ht transmission through or from transparent or reflective articles is known. For exampLe, in U.S. Patent No.
a844983 there is descri~ed a glass or plastics substrate which in use is susceptible to misting which has on at least one surface an antimist coating of a hydrophllic polyurethane which when hydrated contains from 35 to 60% by weight ~ater and which has a thickness o~ 3 ~m to 50 ~m., Whilst such coatings have good antimist properties, they are not very scratch or abrasion resistant. Moreover, the hydrophilic polyurethanes have tO be employed as coatlngs since they are not amenaible ~o fabrication as free-slanding structures such as rilms or sheets.
In US-A-480012~ there are described scratch resistant coatin~s for peroxide curable polyurethane elastomers which comprise a polyfunc~ional monomer having three or more acryloioxy groups per molecule and at least one ~J-vlnyl imido group con~ain~ng monomer.
~he coatin~s are formed by first coatin~ the inside o~
21~2373 the mold for the polyurelhane with the ~cryloloxy-N-vinyi/imido group containing monomers, ~uring ~he in-mold coaling, ~as~ing the urethane composi~ion into ~he mold and curing the urethane.
The surface characteristics of products formed by this process are stated to include scratch resistance.
However, such coatings ào not confer antimist properties to the surface.
The invenlion seeks to provide a polymer composition which not only has the good antimist properties of the ~nown hydrophilic polyurethane materials but also has-good scratch and abrasion resistance and is capable of being formed into free standing structures sucn as films or sheets as well as being useful for co~tin~ substrates such as those of glass or plastic ~ateria~.
The presen~ Lnvenlion ~herefore provides a composition of matt~r having antifog properties comprising a hydr~philic polyurethane in admixture wlth a compatible polymer.
By the term 'compa~ible' is meant that the polymers will co-exist with the polyurethane componen~
wi~hou~ any phase separa~iQn ~hen the polyurethane and .~ke~rnP~a 3 polymer components are admixed. Suitably such polyurethane polymer mixtures will exhibit good light transmitting properties.
The compatible polymers may be homopolymers or copolymers or mixtures of such polymers. Aptly such polymers are derived from monomers or oligomers having ethylenic unsaturation.
The composition of the invention may be formed by, for example, drying mixtures of the polyurethane and other polymer components from a solution thereof or by polymerising the precursors for compatible polymer in the presence of the hydrophilic polyurethane component, optionally in the presence of suitable 15 catalysts and/or polymerisation initiators. Suitable precursors include monomers or oligomers which contain ethylenic saturation.
Thus in accordance with an embodiment of the present invention there is provided a curable composition comprising a 20 hydrophilic polyurethane and a polymerisable compound containing polyfunctional acrylic unsaturation The polymerisable compound containing acryiic unsaturation (hereinafter called 'acrylic component') may be oligomeric in nature.
25 The component may contain acrylate or methacrylate groups. Aptly the acrylic component contains at least three acrylically unsaturated groups. Favoured acrylic components are polyfunctional ether acrylates, preferably containing at least three acryloloxy groups.
More favoured ether acrylates are penta or hexacrylates. Preferred 30 acrylic components for use in the present invention are dipentaerithrytol penta- and hexacrylates pentaerithrytol triacrylate and 1,6 hexane diol - diacrylate.
Suitable hardness and antimist properties may be achieved by 35 the use of less than 50% by weight of the acrylic component.
At~
21~12~7~
The compositions of the invention contain acrylic unsaturation and are cured by cross-linking through the ethylenic bonds.
Accordingly, the compositions of the invention may desirably contain initiators to promote cross-linking. The compositions may be cured 5 by radiation including thermal radiation, actinic, infra-red and ultra-violet radiation and electron beam. Favoured compositions may contain a photo-initiator reactive to U.V. Iight. Such initiators may be present in the compositions of the invention or solutions thereof in conventional amounts.
Ai/lE~JDED SHEET
W094/04587 2 1~ 2 3 7 ~ PCT/GB93/017~
_ 5 _ In addition to c~oss-Lin~Lng of the acrylic component of the composition, ~he polyurethane component may also contain ethylenic unsaturation which may be cross-linkable. For example, the polyurethane may be a urethane-acr~late bloc~ copolymer.
Oligomeric materials which contain unsaturation and which are suitable ~or use in the present invention include hexafunctional aliphatic or aromatic urethane acrylates, difunctional aliphatic or aromatic urethane acrylates, epoxy Novalac acrylates, polyester tetra-acrylates and siloxane di-or hexa acrylates. A
less preferred but still useful component is methyl methacrylate.
In accordance with another embodiment of the invention the composition will comprise a mixture of a hydrophilic polyurethane and a~ least one other compatible polymer conlaining residues of a monomer having vinyl unsaturation. Drecursors for compositions of this type may comprise a mixture of the polyurethane and =he compatible polymer in a single or mixture of co-solvents. Suita~ly the compositions of the invention are formed upon drylng precursor mixture and evaporating the solvenl thererom.
W094/04587 2 ~ ~ 2 3 7 ~ PCT/GB93/017~ ~
Apt polymer materials derived from vinyl or e~hylenically unsa~urated precursors nerein after referred to as the ~inyl component' include vinyl ~hloride-vinyl acelate copolymers, hydroxy modified vinyl chloride-vinyl ace~ate copolymers, vinyl chloride-vinyl acetate copolymers modified with alpha-beta unsalurated carboxylic acids or epoxy compounds, polyacrylates and methacrylates, for example polymethyl methacr~la~es and styrene polymers and polymer blends such as slyrene-acrylonitrile and styrene-maleic acid anAydrid polymers. Suitable vinyl components are available under the trade name UCAR from Union Carbide.
Aptly, composltions of the present invention based on hydrophi~i- polyurethanes and vinyl components will contain at leas~ S~ by wei~ht of the total composition of vin~ mponent. Favourably, the composition will conlaln at least 50% by weight of hydrophilic polyurelhane. Preferably, the compositions of the present inven~ion will contain at least 10~ by weight of the vinyl _omponent and typically will contain about 15~ be weiqht of vinyl component.
The hydrophiLic polyurethane contributes properties of ~ater-~sorption to the compositions of the invention. ~uitably, the compositions of the ' ~ W094/~87 2~ 73 PCT/GB93/017 invention, when cured, will contain a~ leas~ 30~ bv ~eight ~ater when nydrated.
Aptly the hyàrophilic polyurethanes for use in the composition of the invention will contain at leas 35% by weight water when hydrated. Favourably, the hydrophilic polyurethane will contain at least ~0~ by weight when hydrated and more favourably may contain up to 60% or up to 90% waler when hydrated. Suitable hydrophilic polyurethanes for use in the compositions of the invention include those described in US-A-4844983.
Hydrophilic polyurethanes which may be used in the present invention will be any of those which have the water content as hereinbefore described. The saturation water content of the hydrophilic polyurethane will not however be such as to cause it to delaminate from a substrate. Favoured hydrophilic polyurethanes for use in the invention are those which are linear, that is are substantially free of cross links and which therefore are soluble in organic solvents.
The hvdrophilic polyure~hanes suitable for use in the present invention may be polyether or polyester polyurethanes. Sui~able p~lyesters which ~ive rise WOg4/o4582l 12 3 7 ~ PCT/GB93/0l7~ ~
;~
polyurethanes include polyesters of adipic acid such as ~u~ylene aaipate. However it is preferred to use hydropnilic polyurethanes which are polyether polyurethanes. It is particularly preferred therefore to use hydrophilic Dolyurethanes which are linear polyether polyure~hanes.
Apt linear polyelher polyurethanes may be random polymers containina e~her units derived from diolic compounds which have been reacted with diisocyanates.
Suitable linear polye~her polyurethanes include those described in European Patent Specification No.050035 at page 12 line l to page 14 line 10 and at page 32 line 7 to 33 line 12, which are incorporated herein by cross-reference and which have the required water content when hydrated.
Particularl~ apl LS a linear polyether polyurethane which employs poly (ethylene glycol) derived blocks alon~ ~oge~her with a chain extender and a diisocyanate. Suitably the poly (ethylene glycol) may have a molecular weight of between 600 and 6000 and more suitably or belween 800 and 2000. A particularly preferred poly (ethyiene glycol) has a molecular weight of 1540. Suitably the chain extender will be an aliphatic diol or diamine or amineol containing up to lO carbon atoms and most suitably up to 4 carbon atoms.
W094/04587 PCT/GB93/017~
~1 21~7~
g Suitably the aiisocyanate such as toluene diisocyanate, 1, 6-hexamethylene diisocyanate or 4, 4'-dicyclohexyl-methane diisocyanate. A preferred diisocyanate is 4,4'-dicyclohexylmethane diisocyanate.
The ratio of hydrophilic polyurethane to acrylic vinyl component as well as the hydrophilic nature of the polyurethane will affect the physical properties of the cured composition of the invention. The greater the amount of polymer component the greater will be the resistance to abrasion, especially where acrylic components are employed whereas the greater the amount of hydrophilic polyurethane and/or the greater the hydrophilicity of the polyurethane component the better will be the antimist properties. The concentration o~
hydrophilic polyurethane in the composition may range from 10% to 99.0% by weight of the total weight of the composition. Aptly the composition of the present invention may contain from 10 to 90% by weight of the hydrophilic polyurethane.
The composition of the invention may be cast, for example, from solution, to form self supporting sheets or film coatings. Thus the compositions may also contain other processing aids such as flow promoters.
Suitable flow aids may include fully reacted materials such as silicone fluids or reactive materials such as W094/04587 2 ~ ~ 2 3 ~ ~ PCT/GBg3/017~
o di-and hexa-func~lonal silicone acrylates.
Both the nature and concentration of the acrylic or vinyl componenl will also affect the shaping or forming properties of the composition. The composition of the invention may be in the form of a solution suitable for casting or moulding in which the solvents for each of the resin components are compatible with each other. Aptly bo~h ~he polyurethane and acrylic or vinyl componen~s will be dissolved in a common solvent therefor. Favourably the solvent or solvents will be chosen to provide a solution having a viscosity suitable for it to be cast into a sheet or formed into a film. Apt solvents ~or use in the present invention are ketones, esters and alcohols as well as mixtures thereof. Examples of ~uitable organic solvents include propyl acetate, haloaenated hydrocarbons such as methylene dichloride, alkanols such as methanol or ethanol (optionally contalning small amounts of water), ketones such as ace~one or methyl ethyl ketone, methyl iso~utylketone, 2-methoxyethanol 2-ethoxyethanol, diacetone alcohol or ~ixtures of these solvents.
Preferred solvents are Z-ethyoxyethanol, industrial methylated spirits (IMS) or IMS together with 2 methoxyethanol in a ratio of 3:1. Normally and prererably the hydrophilic polyurethane component will be applied in its non-hydrated state.
W O 94/04587 ~ 1 ~ 2~ 7 ~ PC~r/G B93/01744 Those compositions or precursors of the invention which contain acrylic unsaturation are cured by cross-linking through the ethylenic bonds.
Accordingly, the compositions of the invention may desirably contain initiators to promote cross-linking.
The compositions may be cured by radiation including thermal radiation, actinic, infra-red and ultra-violet radiation and electron beam.
Favoured compositions may contain a photo-iniator reactive to U.V. light. Such inhibitors may be present in the compositions of the invention or solutions thereof in conventional amounts.
In addition to cross-linking of the acrylic component of the composition, the polyurethane component may also contain ethylenic unsaturation which may be cross-linkable. For example, the polyurethane may be a urethane-acrylate block copolymer. Preferably the compositions of the invention are dried to remove solvent prior to cross linking.
The solids contents of solutions of compositions of the invention are chosen to provide a balance of good rheological, drying and film-forming properties.
Aptly, the solids content (polyurethane and acrylic or W094/04587 2 14 2 3 73 PCT/GBg3/017~ ~
vinyl components) will be less than 50%, ~ore aptly less than about 25~. ~
Coatings in accordance with the invention may be prepared by conventional methods of coating surfaces such as dip coatin~, sprayinq, painting, knife-coating, on line coating or by printing. In such processes the composition of the invention is dissolved in a suitable organic solvent, for exampie having a solids content of up to 30~ (by wei~nt) or more favourably as a 5 to 15%
solution for dip coating and 5 to 25% for spray coating.
When the coating is to be used in a high quality optical product, such as on a lens, it is preferred that the coating is applied as the result of dip coating. In this process the solution of the polymer composition is placed in a suitable container which is raised mechanically in a controlled manner to immerse the substrate. Th~ container is then lowered at an appropriate rate to qive the desired coating thickness.
The thickness of the coating depends upon both the solution strength, the ~iscosity of the solution and the rate of withdrawal of the substrate from the container. Favourably the process is carried out at between 15 and 30C. The solvent is removed from the coatina after withdrawal from the solution using a s~ I A ~ ~ r~ ~ PCI/GB93/01744 WO 94/04587 ~ h curren~ of air and preferably a current of warm air at a temperature of ~0 to 70. Drying at this temperature imparts a qloss to the coating thereby presenting a better optical appearance to the coated substrate.
It is possible, to apply a coating by preforming the thin film of the hydrophilic polyurethane - polymer compositions of the invention and adhering it to the surface of the glass or plastics substrate which is required to be rendered antimisting. Aptly, the thin film may be adhered by means of a transparent adhesive which is inert to the film and the substrate.
The composition of the invention may be cast, for example, from solution, to form self supporting sheets or film coatings. Thus the compositions may also contain other processing aids such as flow promoters.
When cast into sheets the compositions may be used for glazing purposes such as for window panes.
Alternatively, the compositions may be cast as films onto preformed substrates such as those formed from glass or plastics materials, e.g. polyacrylic or polycarbonate resins ~o maintain or improve light transmission or, if used as mirror, to improve or maintain reflective properties. When C~st into films W094/04587 21 ~ 2 ~ 7 3 PCT/GB93/017~ ~ ' the compositions or the invention may be applied from solutions typically containing greater than 30% by weight solids e.g. 30-40% by weight solids.
Although the compositions of the present invention are light transmitting some sacrifice of the light transmitting properties compared with the base polyurethane in favour of scratch or abrasion resistance may occur when the compositions comprise an acrylic component. We have found however that the light transmitting properties of the hydrophilic polurethane can be retained when vinyl component formations are utilised. Such compositions although not so scratch resistant as the urethane-acrylic components may be formulated into free-standing films for use in multilayer applications such as 'peel-off' visors for helmets such as those for motor-cycling and sports activities withoul loss of optical clarity.
The antifogging properties of composition of the present invention ~ill greatly exceed the performance specification described in DIN 4646 part 8 (1986) for 'Lenses for eye protectors - Antifogging test'.
Preferred compositions of the invention comprising 10%
of the vinyl based resins when tested to DIN 4646/8 will transmit 80% of the original transmittence for longer than lO seconds.
~ W094/04587 21 q 2 3 7 3 PCT/GB93/017~
, The present invention will be illustrateà by the following example.
ExamPle 1 Ninety parts by weight of a hydrophilic polyurethane, prepared in accordance with the method described at lines 4 to Z3, column 7 of US-A-4844983 were mixed with nine parts by weight dipentaerithrylol penta acrylate, 0.5 part of a photo initiator, 0.5 parts of a silicone fluid flow aid and blend of solvents comprising methylisobutylketone, propyl acetate 2-ethoxyethanol to produce a solution being a 15% by weight solids content.
The solution was sprayed onto a sheet of polymethyl methacrylate and cured under a W lamp. A
further sheet was left uncoated.
Both sheets were then placed over a water ba~h containing water at 45C. After two seconds the uncoated sheet be~an to mist over and was completely 'opaque' after about ten seconds. The coated sheet did not start mistinq over until two minutes had elapsed and then did not completely mist over.
W094/04587 2 1~ 2 ~ 7 3 PCT/GB93/017~ ~
Further samples of both sheets were affixed to a mirror mounted within a shower cubicle. The shower unit was operated at maximum temperature. Inspection of the sheets showed that the uncoated sheet misted over whereas the reflective properties of the coated sheet remained intact.
ExamPle 2 A solution of a hydrophilic polyurethane, prepared in accordance with the procedure described in Example 1, was found by slowly adding 80 parts by weight to 2 ethyoxyethanol maintained at room temperature. 19 parts by weight of dipentaaerithroytol hexa-acrylate were added slowly with agitation to the polyurethane solution until dissolved and thereafter a photo initiator (DAROCURE 1173, available from CIBA-GEIGY) and liquid flow aid (silicone acrylate) added. The solids content of the result mixture was adjusted to 17~ by weight.
The solution was then coated onto a sheet of perspex and passed through a drying tunnel maintained at 50C for a period of 5 minutes and then under a W
lamp to cure the resin. After drying and curing, the coated sheet was subjected to testing according to DIN
4646 part 8. Under the test conditions fogging did not commence until 15 seconds had elapsed.
~ W094/04587 2 1 ~ ~ 9 7 3 PCT/GBg3/017~
ExamPle 3 A 20% by weight solution was first formed by dissolving 85 parts by weight in ethoxyethanol. A
hydroxyl modified vinyl chloride-vinyl acetate copolymer (14.9 parts by weight) was added slowly with agitation until the mixture was clear and free from striations. Liquid silicone acrylate (0.1 part by weight) was then added as a flow aid and the solids concentration adjusted to 15% by weight. The solution was then applied as an antimist coating to a motor cycle helmet visor.
The coated visor was passed through a drying tunnel, maintained at 50C for a period of 5 minutes.
r~ t ' J ~
Pol~mer ~roducts .
~ his invention rela~es ~o polymer composl~ions and` more particularly tO compositions for use in the manufacture of transparent or reflective articles.
The use of polymer films for improving the Li~ht transmission through or from transparent or reflective articles is known. For exampLe, in U.S. Patent No.
a844983 there is descri~ed a glass or plastics substrate which in use is susceptible to misting which has on at least one surface an antimist coating of a hydrophllic polyurethane which when hydrated contains from 35 to 60% by weight ~ater and which has a thickness o~ 3 ~m to 50 ~m., Whilst such coatings have good antimist properties, they are not very scratch or abrasion resistant. Moreover, the hydrophilic polyurethanes have tO be employed as coatlngs since they are not amenaible ~o fabrication as free-slanding structures such as rilms or sheets.
In US-A-480012~ there are described scratch resistant coatin~s for peroxide curable polyurethane elastomers which comprise a polyfunc~ional monomer having three or more acryloioxy groups per molecule and at least one ~J-vlnyl imido group con~ain~ng monomer.
~he coatin~s are formed by first coatin~ the inside o~
21~2373 the mold for the polyurelhane with the ~cryloloxy-N-vinyi/imido group containing monomers, ~uring ~he in-mold coaling, ~as~ing the urethane composi~ion into ~he mold and curing the urethane.
The surface characteristics of products formed by this process are stated to include scratch resistance.
However, such coatings ào not confer antimist properties to the surface.
The invenlion seeks to provide a polymer composition which not only has the good antimist properties of the ~nown hydrophilic polyurethane materials but also has-good scratch and abrasion resistance and is capable of being formed into free standing structures sucn as films or sheets as well as being useful for co~tin~ substrates such as those of glass or plastic ~ateria~.
The presen~ Lnvenlion ~herefore provides a composition of matt~r having antifog properties comprising a hydr~philic polyurethane in admixture wlth a compatible polymer.
By the term 'compa~ible' is meant that the polymers will co-exist with the polyurethane componen~
wi~hou~ any phase separa~iQn ~hen the polyurethane and .~ke~rnP~a 3 polymer components are admixed. Suitably such polyurethane polymer mixtures will exhibit good light transmitting properties.
The compatible polymers may be homopolymers or copolymers or mixtures of such polymers. Aptly such polymers are derived from monomers or oligomers having ethylenic unsaturation.
The composition of the invention may be formed by, for example, drying mixtures of the polyurethane and other polymer components from a solution thereof or by polymerising the precursors for compatible polymer in the presence of the hydrophilic polyurethane component, optionally in the presence of suitable 15 catalysts and/or polymerisation initiators. Suitable precursors include monomers or oligomers which contain ethylenic saturation.
Thus in accordance with an embodiment of the present invention there is provided a curable composition comprising a 20 hydrophilic polyurethane and a polymerisable compound containing polyfunctional acrylic unsaturation The polymerisable compound containing acryiic unsaturation (hereinafter called 'acrylic component') may be oligomeric in nature.
25 The component may contain acrylate or methacrylate groups. Aptly the acrylic component contains at least three acrylically unsaturated groups. Favoured acrylic components are polyfunctional ether acrylates, preferably containing at least three acryloloxy groups.
More favoured ether acrylates are penta or hexacrylates. Preferred 30 acrylic components for use in the present invention are dipentaerithrytol penta- and hexacrylates pentaerithrytol triacrylate and 1,6 hexane diol - diacrylate.
Suitable hardness and antimist properties may be achieved by 35 the use of less than 50% by weight of the acrylic component.
At~
21~12~7~
The compositions of the invention contain acrylic unsaturation and are cured by cross-linking through the ethylenic bonds.
Accordingly, the compositions of the invention may desirably contain initiators to promote cross-linking. The compositions may be cured 5 by radiation including thermal radiation, actinic, infra-red and ultra-violet radiation and electron beam. Favoured compositions may contain a photo-initiator reactive to U.V. Iight. Such initiators may be present in the compositions of the invention or solutions thereof in conventional amounts.
Ai/lE~JDED SHEET
W094/04587 2 1~ 2 3 7 ~ PCT/GB93/017~
_ 5 _ In addition to c~oss-Lin~Lng of the acrylic component of the composition, ~he polyurethane component may also contain ethylenic unsaturation which may be cross-linkable. For example, the polyurethane may be a urethane-acr~late bloc~ copolymer.
Oligomeric materials which contain unsaturation and which are suitable ~or use in the present invention include hexafunctional aliphatic or aromatic urethane acrylates, difunctional aliphatic or aromatic urethane acrylates, epoxy Novalac acrylates, polyester tetra-acrylates and siloxane di-or hexa acrylates. A
less preferred but still useful component is methyl methacrylate.
In accordance with another embodiment of the invention the composition will comprise a mixture of a hydrophilic polyurethane and a~ least one other compatible polymer conlaining residues of a monomer having vinyl unsaturation. Drecursors for compositions of this type may comprise a mixture of the polyurethane and =he compatible polymer in a single or mixture of co-solvents. Suita~ly the compositions of the invention are formed upon drylng precursor mixture and evaporating the solvenl thererom.
W094/04587 2 ~ ~ 2 3 7 ~ PCT/GB93/017~ ~
Apt polymer materials derived from vinyl or e~hylenically unsa~urated precursors nerein after referred to as the ~inyl component' include vinyl ~hloride-vinyl acelate copolymers, hydroxy modified vinyl chloride-vinyl ace~ate copolymers, vinyl chloride-vinyl acetate copolymers modified with alpha-beta unsalurated carboxylic acids or epoxy compounds, polyacrylates and methacrylates, for example polymethyl methacr~la~es and styrene polymers and polymer blends such as slyrene-acrylonitrile and styrene-maleic acid anAydrid polymers. Suitable vinyl components are available under the trade name UCAR from Union Carbide.
Aptly, composltions of the present invention based on hydrophi~i- polyurethanes and vinyl components will contain at leas~ S~ by wei~ht of the total composition of vin~ mponent. Favourably, the composition will conlaln at least 50% by weight of hydrophilic polyurelhane. Preferably, the compositions of the present inven~ion will contain at least 10~ by weight of the vinyl _omponent and typically will contain about 15~ be weiqht of vinyl component.
The hydrophiLic polyurethane contributes properties of ~ater-~sorption to the compositions of the invention. ~uitably, the compositions of the ' ~ W094/~87 2~ 73 PCT/GB93/017 invention, when cured, will contain a~ leas~ 30~ bv ~eight ~ater when nydrated.
Aptly the hyàrophilic polyurethanes for use in the composition of the invention will contain at leas 35% by weight water when hydrated. Favourably, the hydrophilic polyurethane will contain at least ~0~ by weight when hydrated and more favourably may contain up to 60% or up to 90% waler when hydrated. Suitable hydrophilic polyurethanes for use in the compositions of the invention include those described in US-A-4844983.
Hydrophilic polyurethanes which may be used in the present invention will be any of those which have the water content as hereinbefore described. The saturation water content of the hydrophilic polyurethane will not however be such as to cause it to delaminate from a substrate. Favoured hydrophilic polyurethanes for use in the invention are those which are linear, that is are substantially free of cross links and which therefore are soluble in organic solvents.
The hvdrophilic polyure~hanes suitable for use in the present invention may be polyether or polyester polyurethanes. Sui~able p~lyesters which ~ive rise WOg4/o4582l 12 3 7 ~ PCT/GB93/0l7~ ~
;~
polyurethanes include polyesters of adipic acid such as ~u~ylene aaipate. However it is preferred to use hydropnilic polyurethanes which are polyether polyurethanes. It is particularly preferred therefore to use hydrophilic Dolyurethanes which are linear polyether polyure~hanes.
Apt linear polyelher polyurethanes may be random polymers containina e~her units derived from diolic compounds which have been reacted with diisocyanates.
Suitable linear polye~her polyurethanes include those described in European Patent Specification No.050035 at page 12 line l to page 14 line 10 and at page 32 line 7 to 33 line 12, which are incorporated herein by cross-reference and which have the required water content when hydrated.
Particularl~ apl LS a linear polyether polyurethane which employs poly (ethylene glycol) derived blocks alon~ ~oge~her with a chain extender and a diisocyanate. Suitably the poly (ethylene glycol) may have a molecular weight of between 600 and 6000 and more suitably or belween 800 and 2000. A particularly preferred poly (ethyiene glycol) has a molecular weight of 1540. Suitably the chain extender will be an aliphatic diol or diamine or amineol containing up to lO carbon atoms and most suitably up to 4 carbon atoms.
W094/04587 PCT/GB93/017~
~1 21~7~
g Suitably the aiisocyanate such as toluene diisocyanate, 1, 6-hexamethylene diisocyanate or 4, 4'-dicyclohexyl-methane diisocyanate. A preferred diisocyanate is 4,4'-dicyclohexylmethane diisocyanate.
The ratio of hydrophilic polyurethane to acrylic vinyl component as well as the hydrophilic nature of the polyurethane will affect the physical properties of the cured composition of the invention. The greater the amount of polymer component the greater will be the resistance to abrasion, especially where acrylic components are employed whereas the greater the amount of hydrophilic polyurethane and/or the greater the hydrophilicity of the polyurethane component the better will be the antimist properties. The concentration o~
hydrophilic polyurethane in the composition may range from 10% to 99.0% by weight of the total weight of the composition. Aptly the composition of the present invention may contain from 10 to 90% by weight of the hydrophilic polyurethane.
The composition of the invention may be cast, for example, from solution, to form self supporting sheets or film coatings. Thus the compositions may also contain other processing aids such as flow promoters.
Suitable flow aids may include fully reacted materials such as silicone fluids or reactive materials such as W094/04587 2 ~ ~ 2 3 ~ ~ PCT/GBg3/017~
o di-and hexa-func~lonal silicone acrylates.
Both the nature and concentration of the acrylic or vinyl componenl will also affect the shaping or forming properties of the composition. The composition of the invention may be in the form of a solution suitable for casting or moulding in which the solvents for each of the resin components are compatible with each other. Aptly bo~h ~he polyurethane and acrylic or vinyl componen~s will be dissolved in a common solvent therefor. Favourably the solvent or solvents will be chosen to provide a solution having a viscosity suitable for it to be cast into a sheet or formed into a film. Apt solvents ~or use in the present invention are ketones, esters and alcohols as well as mixtures thereof. Examples of ~uitable organic solvents include propyl acetate, haloaenated hydrocarbons such as methylene dichloride, alkanols such as methanol or ethanol (optionally contalning small amounts of water), ketones such as ace~one or methyl ethyl ketone, methyl iso~utylketone, 2-methoxyethanol 2-ethoxyethanol, diacetone alcohol or ~ixtures of these solvents.
Preferred solvents are Z-ethyoxyethanol, industrial methylated spirits (IMS) or IMS together with 2 methoxyethanol in a ratio of 3:1. Normally and prererably the hydrophilic polyurethane component will be applied in its non-hydrated state.
W O 94/04587 ~ 1 ~ 2~ 7 ~ PC~r/G B93/01744 Those compositions or precursors of the invention which contain acrylic unsaturation are cured by cross-linking through the ethylenic bonds.
Accordingly, the compositions of the invention may desirably contain initiators to promote cross-linking.
The compositions may be cured by radiation including thermal radiation, actinic, infra-red and ultra-violet radiation and electron beam.
Favoured compositions may contain a photo-iniator reactive to U.V. light. Such inhibitors may be present in the compositions of the invention or solutions thereof in conventional amounts.
In addition to cross-linking of the acrylic component of the composition, the polyurethane component may also contain ethylenic unsaturation which may be cross-linkable. For example, the polyurethane may be a urethane-acrylate block copolymer. Preferably the compositions of the invention are dried to remove solvent prior to cross linking.
The solids contents of solutions of compositions of the invention are chosen to provide a balance of good rheological, drying and film-forming properties.
Aptly, the solids content (polyurethane and acrylic or W094/04587 2 14 2 3 73 PCT/GBg3/017~ ~
vinyl components) will be less than 50%, ~ore aptly less than about 25~. ~
Coatings in accordance with the invention may be prepared by conventional methods of coating surfaces such as dip coatin~, sprayinq, painting, knife-coating, on line coating or by printing. In such processes the composition of the invention is dissolved in a suitable organic solvent, for exampie having a solids content of up to 30~ (by wei~nt) or more favourably as a 5 to 15%
solution for dip coating and 5 to 25% for spray coating.
When the coating is to be used in a high quality optical product, such as on a lens, it is preferred that the coating is applied as the result of dip coating. In this process the solution of the polymer composition is placed in a suitable container which is raised mechanically in a controlled manner to immerse the substrate. Th~ container is then lowered at an appropriate rate to qive the desired coating thickness.
The thickness of the coating depends upon both the solution strength, the ~iscosity of the solution and the rate of withdrawal of the substrate from the container. Favourably the process is carried out at between 15 and 30C. The solvent is removed from the coatina after withdrawal from the solution using a s~ I A ~ ~ r~ ~ PCI/GB93/01744 WO 94/04587 ~ h curren~ of air and preferably a current of warm air at a temperature of ~0 to 70. Drying at this temperature imparts a qloss to the coating thereby presenting a better optical appearance to the coated substrate.
It is possible, to apply a coating by preforming the thin film of the hydrophilic polyurethane - polymer compositions of the invention and adhering it to the surface of the glass or plastics substrate which is required to be rendered antimisting. Aptly, the thin film may be adhered by means of a transparent adhesive which is inert to the film and the substrate.
The composition of the invention may be cast, for example, from solution, to form self supporting sheets or film coatings. Thus the compositions may also contain other processing aids such as flow promoters.
When cast into sheets the compositions may be used for glazing purposes such as for window panes.
Alternatively, the compositions may be cast as films onto preformed substrates such as those formed from glass or plastics materials, e.g. polyacrylic or polycarbonate resins ~o maintain or improve light transmission or, if used as mirror, to improve or maintain reflective properties. When C~st into films W094/04587 21 ~ 2 ~ 7 3 PCT/GB93/017~ ~ ' the compositions or the invention may be applied from solutions typically containing greater than 30% by weight solids e.g. 30-40% by weight solids.
Although the compositions of the present invention are light transmitting some sacrifice of the light transmitting properties compared with the base polyurethane in favour of scratch or abrasion resistance may occur when the compositions comprise an acrylic component. We have found however that the light transmitting properties of the hydrophilic polurethane can be retained when vinyl component formations are utilised. Such compositions although not so scratch resistant as the urethane-acrylic components may be formulated into free-standing films for use in multilayer applications such as 'peel-off' visors for helmets such as those for motor-cycling and sports activities withoul loss of optical clarity.
The antifogging properties of composition of the present invention ~ill greatly exceed the performance specification described in DIN 4646 part 8 (1986) for 'Lenses for eye protectors - Antifogging test'.
Preferred compositions of the invention comprising 10%
of the vinyl based resins when tested to DIN 4646/8 will transmit 80% of the original transmittence for longer than lO seconds.
~ W094/04587 21 q 2 3 7 3 PCT/GB93/017~
, The present invention will be illustrateà by the following example.
ExamPle 1 Ninety parts by weight of a hydrophilic polyurethane, prepared in accordance with the method described at lines 4 to Z3, column 7 of US-A-4844983 were mixed with nine parts by weight dipentaerithrylol penta acrylate, 0.5 part of a photo initiator, 0.5 parts of a silicone fluid flow aid and blend of solvents comprising methylisobutylketone, propyl acetate 2-ethoxyethanol to produce a solution being a 15% by weight solids content.
The solution was sprayed onto a sheet of polymethyl methacrylate and cured under a W lamp. A
further sheet was left uncoated.
Both sheets were then placed over a water ba~h containing water at 45C. After two seconds the uncoated sheet be~an to mist over and was completely 'opaque' after about ten seconds. The coated sheet did not start mistinq over until two minutes had elapsed and then did not completely mist over.
W094/04587 2 1~ 2 ~ 7 3 PCT/GB93/017~ ~
Further samples of both sheets were affixed to a mirror mounted within a shower cubicle. The shower unit was operated at maximum temperature. Inspection of the sheets showed that the uncoated sheet misted over whereas the reflective properties of the coated sheet remained intact.
ExamPle 2 A solution of a hydrophilic polyurethane, prepared in accordance with the procedure described in Example 1, was found by slowly adding 80 parts by weight to 2 ethyoxyethanol maintained at room temperature. 19 parts by weight of dipentaaerithroytol hexa-acrylate were added slowly with agitation to the polyurethane solution until dissolved and thereafter a photo initiator (DAROCURE 1173, available from CIBA-GEIGY) and liquid flow aid (silicone acrylate) added. The solids content of the result mixture was adjusted to 17~ by weight.
The solution was then coated onto a sheet of perspex and passed through a drying tunnel maintained at 50C for a period of 5 minutes and then under a W
lamp to cure the resin. After drying and curing, the coated sheet was subjected to testing according to DIN
4646 part 8. Under the test conditions fogging did not commence until 15 seconds had elapsed.
~ W094/04587 2 1 ~ ~ 9 7 3 PCT/GBg3/017~
ExamPle 3 A 20% by weight solution was first formed by dissolving 85 parts by weight in ethoxyethanol. A
hydroxyl modified vinyl chloride-vinyl acetate copolymer (14.9 parts by weight) was added slowly with agitation until the mixture was clear and free from striations. Liquid silicone acrylate (0.1 part by weight) was then added as a flow aid and the solids concentration adjusted to 15% by weight. The solution was then applied as an antimist coating to a motor cycle helmet visor.
The coated visor was passed through a drying tunnel, maintained at 50C for a period of 5 minutes.
r~ t ' J ~
Claims (16)
1. A composition of matter having antifog properties comprising a hydrophilic polyurethane in admixture with a compatible polymer derived from a polymerisable compound containing polyfunctional acrylic unsaturation.
2. A composition according to claim 1 wherein the polymer comprises a mixture of homo- or co-polymers.
3. A composition according to any one of claims 1 to 2 wherein the polymer is derived from at least one monomer or oligomer containing vinyl unsaturation.
4. Precursor for a composition as defined in any one of the preceding claims comprising a hydrophilic polyurethane and a polymerisable compound containing polyfunctional acrylic unsaturation.
5. A precursor according to claim 6 wherein the polymerisable compound contains at least three acrylically unsaturated groups.
6. A precursor according to claim 4 or 5 wherein the polymerisable compound is a polyfunctional ether acrylate.
7. A precursor according to claim 6 wherein the acrylate is dipentaerithrytol pent- or hexa- acrylate.
8. A precursor according to any one of claims 4 to 7 comprising a photo initiator.
9. A composition according to any one of claims 3 to 10 wherein the ethylenically unsaturated monomer is a vinyl monomer.
10. A composition or precursor according to any one of the preceding claims wherein the hydrophilic polyurethane contains at least 35% by weight water when hydrated.
11. A composition or precursor according to claim 11 wherein the hydrophilic polyurethane contains up to 60% by weight water when hydrated.
12. A composition or precursor according to any one of the preceding claims comprising up to 30% by weight water when hydrated.
13. A light transmitting article formed from a composition or precursor as defined in any one of the preceding claims.
14. An article according to claim 13 comprising a light transmitting substrate having coated thereon a layer of composition or precursor as defined in any one of claims 1 to 12.
15. An article according to claim 13 moulded, formed or shaped from a composition or precursor as defined in any one of claims 1 to 12.
16. An article according to any one of claims 13 to 15 in form of an eye-protector.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB929217625A GB9217625D0 (en) | 1992-08-19 | 1992-08-19 | Polymer materials |
| GB9217625.4 | 1992-08-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2142373A1 true CA2142373A1 (en) | 1994-03-03 |
Family
ID=10720610
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2142373 Abandoned CA2142373A1 (en) | 1992-08-19 | 1993-08-17 | Polymer products |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0656022A1 (en) |
| JP (1) | JPH08500381A (en) |
| AU (1) | AU4727493A (en) |
| CA (1) | CA2142373A1 (en) |
| GB (2) | GB9217625D0 (en) |
| WO (1) | WO1994004587A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030205059A1 (en) | 2002-05-02 | 2003-11-06 | Hussmann Corporation | Merchandisers having anti-fog coatings and methods for making the same |
| US20050202178A1 (en) | 2002-05-02 | 2005-09-15 | Hussmann Corporation | Merchandisers having anti-fog coatings and methods for making the same |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2806217A1 (en) * | 1978-02-14 | 1979-08-16 | Bayer Ag | Anti-mist coatings for glass etc. - comprising a poly:isocyanate, an amine cpd., a poly:hydroxy cpd. and sulphonic or sulphinic acid |
| US4467073A (en) * | 1982-10-20 | 1984-08-21 | Hydromer, Inc. | Transparent anti-fog coating compositions |
| GB2150938B (en) * | 1983-12-05 | 1987-04-23 | Tyndale Plains Hunter Limited | Hydrophilic polyurethane acrylate compositions |
| AU588910B2 (en) * | 1985-08-20 | 1989-09-28 | Smith & Nephew Associated Companies Plc | Coated glass |
| AU594500B2 (en) * | 1987-04-21 | 1990-03-08 | W.L. Gore & Associates, Inc. | Radiation curable compositions for hydrophilic coatings |
| US4800123A (en) * | 1987-09-03 | 1989-01-24 | Freeman Chemical Corporation | In-mold scratch resistant coating for peroxide curable urethane elastomers |
| US5115056A (en) * | 1989-06-20 | 1992-05-19 | Ciba-Geigy Corporation | Fluorine and/or silicone containing poly(alkylene-oxide)-block copolymers and contact lenses thereof |
| JP2816036B2 (en) * | 1991-07-09 | 1998-10-27 | 早川ゴム株式会社 | Oligomers for antifogging compositions |
-
1992
- 1992-08-19 GB GB929217625A patent/GB9217625D0/en active Pending
-
1993
- 1993-08-17 WO PCT/GB1993/001744 patent/WO1994004587A1/en not_active Application Discontinuation
- 1993-08-17 EP EP93918041A patent/EP0656022A1/en not_active Withdrawn
- 1993-08-17 AU AU47274/93A patent/AU4727493A/en not_active Abandoned
- 1993-08-17 JP JP6506037A patent/JPH08500381A/en active Pending
- 1993-08-17 GB GB9502155A patent/GB2284821A/en not_active Withdrawn
- 1993-08-17 CA CA 2142373 patent/CA2142373A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| AU4727493A (en) | 1994-03-15 |
| WO1994004587A1 (en) | 1994-03-03 |
| JPH08500381A (en) | 1996-01-16 |
| GB9217625D0 (en) | 1992-09-30 |
| GB2284821A (en) | 1995-06-21 |
| GB9502155D0 (en) | 1995-03-22 |
| EP0656022A1 (en) | 1995-06-07 |
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