EP0314348A2
Expired / Lapsed
EP
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Thermal transfer printing dyesheet and backcoat composition therefor
Assignee: Imperial Chemical Industries Ltd
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Filing: 1988-10-13
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Granted: —
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Expires: 2008-10-13
Abstract
Abstract For a thermal transfer dyesheet, a protective backcoat is provided by polymerising acrylic functional groups in a composition comprising: an organic resin comprising at least one polyfunctional material having a plurality of pendant or terminal acrylic groups per molecule available for cross-linking, at least 10% by weight of the polyfunctional material having 4-8 such acrylic groups per molecule; at least one linear organic polymer soluble or partially soluble in the resin, and comprising 1-40% by weight of the resin/polymer mixture; a slip agent selected from derivatives of long chain carboxylic or phosphoric acids, long alkyl chain esters of phosphoric acid, and long alkyl chain acrylates; an antistatic agent soluble in the resin, and a solid particulate antiblocking agent less than 5 µm in diameter. Resins having predominently 5-7 acrylic functional groups per molecule, are preferred for enhancing protection against the thermal head, especially when used in a mixture also containing molecules having only 2-4 such acrylic groups per molecule. The effect of using such mixtures to cross link molecules of both high and low acrylic functionalities in the presence of the linear polymers, is to enable good thermal protection to be provided by a durable low friction coating, which also cleans the thermal head during printing.
Inventors
- 👤 Richard Anthony Hann
- 👤 Barry Pack
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 20:09
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/26; B41M5/382; B41M5/385; B41M5/40; B41M5/405; B41M5/42; B41M5/423; B41M5/426; B41M5/44; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10S428/914; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31786; Y10T428/31797; Y10T428/31855
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
165 words
A dyesheet for thermal transfer printing, comprising a thermoplastic substrate film supporting on one surface at least a dyecoat containing a thermal transfer dye, and having a polymeric back-coat on the other surface, wherein the back-coat consists essentially of a reaction product of polymerising acrylic functional groups in a layer of a coating composition comprising: a) an organic resin comprising at least one polyfunctional material having a plurality of pendant or terminal acrylic groups per molecule available for cross-linking, at least 10% by weight of the polyfunctional material having 4-8 such acrylic groups per molecule; b) at least one linear organic polymer soluble or partially soluble in the resin, and comprising 1-40% by weight of the resin/polymer mixture; c) a slip agent selected from derivatives of long chain carboxylic or phosphoric acids, long alkyl chain esters of phosphoric acid, and long alkyl chain acrylates; d) an antistatic agent soluble in the resin, and e) a solid particulate antiblocking agent less than 5 µm in diameter.
Claim 2
Dependent Claim
165 words
A dyesheet for thermal transfer printing, comprising a thermoplastic substrate film supporting on one surface at least a dyecoat containing a thermal transfer dye, and having a polymeric back-coat on the other surface, wherein the back-coat consists essentially of a reaction product of polymerising acrylic functional groups in a layer of a coating composition comprising: a) an organic resin comprising at least one polyfunctional material having a plurality of pendant or terminal acrylic groups per molecule available for cross-linking, at least 10% by weight of the polyfunctional material having 4-8 such acrylic groups per molecule; b) at least one linear organic polymer soluble or partially soluble in the resin, and comprising 1-40% by weight of the resin/polymer mixture; c) a slip agent selected from derivatives of long chain carboxylic or phosphoric acids, long alkyl chain esters of phosphoric acid, and long alkyl chain acrylates; d) an antistatic agent soluble in the resin, and e) a solid particulate antiblocking agent less than 5 µm in diameter.
Claim 3
Dependent Claim
42 words
A dyesheet as claimed in claim 1, in which at least 10% by weight of the polyfunctional material has 2-4 such acrylic groups per molecule and at least 10% by weight of the polyfunctional material has 5-7 such acrylic groups per molecule.
Claim 4
Dependent Claim
25 words
A dyesheet as claimed in claim 2, in which at least 50% by weight of the polyfunctional material has 5-7 acrylic functional groups per molecule.
Claim 5
Dependent Claim
34 words
A dyesheet as claimed in any one of the preceding claims, in which the polyfunctional material comprises molecules having oligomer backbones selected from urethanes, epoxides and polyesters, to which the acrylic groups are attached.
Claim 6
Dependent Claim
18 words
A dyesheet as claimed in any one of claims 1-3, in which the resin comprises an alkyl diacrylate.
Claim 7
Dependent Claim
31 words
A dyesheet as claimed in any one of the preceding claims, wherein the linear organic polymer of component b is selected from polymethylmethacrylate, polyvinyl chloride, linear polyesters and acrylated polyester polyols.
Claim 8
Dependent Claim
23 words
A dyesheet as claimed in any one of the preceding claims, wherein the slip agent is a divalent metal salt of stearic acid.
Claim 9
Dependent Claim
32 words
A dyesheet as claimed in any one of the preceding claims, wherein a single compound is used to provide both slip and antistatic functional components c and d of the coating composition:
Claim 10
Dependent Claim
39 words
A dyesheet as claimed in any one of the preceding claims, having a dye-barrier layer between the dyecoat and the thermoplastic substrate film, thereby to restrict the amount of dye moving towards the printer head during the printing process.
Claim 11
Dependent Claim
91 words
A dyesheet as claimed in claim 9, wherein the dye-barrier layer comprises the reaction product of polymerising acrylic functional groups in a composition comprising: (a) an organic resin comprising at least one polyfunctional material having a plurality of pendant or terminal acrylic groups per molecule available for cross-linking, at least 50% by weight of the polyfunctional material having at least 4 such acrylic functional groups per molecule, and (b) at least one linear organic polymer soluble or partially soluble in the resin, and comprising 1-40% by weight of the resin/polymer mixture.
Claim 12
Dependent Claim
144 words
A coating compositing for use in the manufacture of dyesheets for thermal transfer printing, the composition comprising: (a) an organic resin comprising at least one polyfunctional material having a plurality of pendant or terminal acrylic groups per molecule available for cross-linking, at least 10% by weight of the polyfunctional material having 4-8 such acrylic groups per molecule; (b) at least one linear organic polymer soluble or partially soluble in the resin, and comprising 1-40% by weight of the resin/polymer mixtures; (c) a slip agent selected from derivatives of long chain carboxylic or phosphoric acids, long alkyl chain esters of phosphoric acid, and long alkyl chain acrylates; (d) a antistatic agent soluble in the resin; (e) a solid particulate antiblocking agent less than 5 µm in diameter, and (f) activation means responsive to thermal or optical stimulus for effecting polymerisation of the acrylic functional groups.
Claim 13
Dependent Claim
144 words
A coating compositing for use in the manufacture of dyesheets for thermal transfer printing, the composition comprising: (a) an organic resin comprising at least one polyfunctional material having a plurality of pendant or terminal acrylic groups per molecule available for cross-linking, at least 10% by weight of the polyfunctional material having 4-8 such acrylic groups per molecule; (b) at least one linear organic polymer soluble or partially soluble in the resin, and comprising 1-40% by weight of the resin/polymer mixtures; (c) a slip agent selected from derivatives of long chain carboxylic or phosphoric acids, long alkyl chain esters of phosphoric acid, and long alkyl chain acrylates; (d) a antistatic agent soluble in the resin; (e) a solid particulate antiblocking agent less than 5 µm in diameter, and (f) activation means responsive to thermal or optical stimulus for effecting polymerisation of the acrylic functional groups.
Claim 14
Dependent Claim
59 words
A process for manufacturing dyesheets for thermal transfer printing, comprising coating one surface of a thermoplastic substrate film with at least a dyecoat composition, and coating the other side with a backcoat composition as claimed in claim 11, thereafter applying the stimulus for effecting polymerisation of the acrylic functional groups to provide a protective backcoat on the substrate film.
Claim 15
Dependent Claim
82 words
A process as claimed in claim 12, in which the backcoat is provided by a continuous in-line process comprising the steps of passing a length of the substrate film through a coating apparatus, coating said other side of the moving film with a layer of the backcoat composition containing as activator means a radiation-responsive sensitiser system, drying the composition, and subjecting the coating to radiation appropriate to effect curing of the composition as the film continues to move through the coating apparatus.
References Cited (Backward Citations)
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