EP0342826A2
Expired / Lapsed
EP
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Release film
Assignee: Imperial Chemical Industries Ltd
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Filing: 1989-05-05
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Granted: —
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Expires: 2009-05-05
Abstract
Abstract A release film comprising an oriented film substrate having an abherent surface layer comprising a chain extended polyurethane resin derived from an isocyanate-reactive polydialkyl siloxane. A preferred substrate is a biaxially oriented polyethylene terephthalate film, and the release film is of particular utility in the production of asphalt roofing materials.
Inventors
- 👤 David Edward Higgins
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 07:01
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/0804; C08J; C08J5/00; C08J5/18; C08G18/28; C08G18/40; C08G18/61; C08J7/00; C08J7/04; C08J7/0427; C08J7/043; C08J7/046; C08J7/056; C09; C09J; C09J7/00; C09J7/20; C09J7/201; C09J7/22; C09J7/40; C09J7/401; D; D06; D06N; D06N5/00; E; E04; E04D; E04D5/00; E04D5/12; C08J2367/00; C08J2367/02; C08J2475/00; C09J2400/00; C09J2400/20; C09J2400/22; C09J2400/226; C09J2467/00; C09J2467/006; C09J2475/00; C09J2475/005; Y; Y10; Y10T; Y10T428/00; Y10T428/14; Y10T428/1452; Y10T428/1457; Y10T428/24; Y10T428/24355; Y10T428/31504; Y10T428/31551; Y10T428/31565; Y10T428/31815
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
80 words
A release film comprising a self-supporting, polymeric film substrate having, on at least one surface thereof, a polymeric abherent layer characterised in that the abherent layer comprises a polyurethane resin which is the reaction product of : (A) a prepolymer obtained by reacting : (i) an organic polyisocyanate, (ii) a polydialkylsiloxane having at least two isocyanate- reactive groups, and (iii) a compound containing a hydrophilic centre and at least two isocyanate and/or isocyanate-reactive groups, and (B) a polyfunctional chain extender.
Claim 2
Dependent Claim
80 words
A release film comprising a self-supporting, polymeric film substrate having, on at least one surface thereof, a polymeric abherent layer characterised in that the abherent layer comprises a polyurethane resin which is the reaction product of : (A) a prepolymer obtained by reacting : (i) an organic polyisocyanate, (ii) a polydialkylsiloxane having at least two isocyanate- reactive groups, and (iii) a compound containing a hydrophilic centre and at least two isocyanate and/or isocyanate-reactive groups, and (B) a polyfunctional chain extender.
Claim 3
Dependent Claim
15 words
A release film according to claim 1 wherein the polymeric film is a thermoplastics film.
Claim 4
Dependent Claim
46 words
A release film according to either of claims 1 and 2 wherein the prepolymer is derived from an additional reactant comprising: (iv) at least one organic polyol having a molecular weight in the range 62 to 6000 and being free from silicon atoms and hydrophilic centres.
Claim 5
Dependent Claim
21 words
A release film according to any one of the preceding claims wherein component (ii) comprises a polydimethyl siloxane diol or triol.
Claim 6
Dependent Claim
18 words
A release film according to any one of the preceding claims wherein component (iii) comprises 2,2-dimethylol propionic acid.
Claim 7
Dependent Claim
22 words
A release film according to any one of the preceding claims wherein the polyfunctional chain extender comprises a resinous inter-molecular cross-linking agent.
Claim 8
Dependent Claim
15 words
A release film according to claim 6 wherein the chain extender comprises a methoxymethyl melamine.
Claim 9
Dependent Claim
21 words
A release film according to any one of the preceding claims wherein the substrate comprises a biaxially oriented polyethylene terephthalate film.
Claim 10
Independent Claim
116 words
A method of producing a release film comprising applying an abherent medium to at least one surface of a self-supporting, polymeric film substrate, the abherent medium being applied before, during or after, any stretching operation employed to effect molecular orientation of the film substrate, and drying the applied medium to form a polymeric abherent layer, characterised in that the abherent medium comprises a dispersion of a polyurethane resin which is the reaction product of: (A) a prepolymer obtained by reacting : (i) an organic polyisocyanate, (ii) a polydimethylsiloxane having at least two isocyanate-reactive groups, and (iii) a compound containing a hydrophilic centre and at least two isocyanate and/or isocyanate-reactive groups, and (B) a polyfunctional chain extender.
Claim 11
Independent Claim
116 words
A method of producing a release film comprising applying an abherent medium to at least one surface of a self-supporting, polymeric film substrate, the abherent medium being applied before, during or after, any stretching operation employed to effect molecular orientation of the film substrate, and drying the applied medium to form a polymeric abherent layer, characterised in that the abherent medium comprises a dispersion of a polyurethane resin which is the reaction product of: (A) a prepolymer obtained by reacting : (i) an organic polyisocyanate, (ii) a polydimethylsiloxane having at least two isocyanate-reactive groups, and (iii) a compound containing a hydrophilic centre and at least two isocyanate and/or isocyanate-reactive groups, and (B) a polyfunctional chain extender.
Claim 12
Dependent Claim
16 words
A method according to claim 9 wherein the abherent medium is applied as an aqueous dispersion.
Claim 13
Dependent Claim
80 words
An asphalt roofing sheet or shingle having an adhesive element on a first surface thereof and a release tape on the second surface thereof, the release tape being positioned to engage with the adhesive element on an adjacent sheet or shingle when the sheets or shingles are stacked, characterised in that the release tape comprises a release film according to any one of claims 1 to 8 or produced by a method according to either of claims 9 and 10.
References Cited (Backward Citations)
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