EP0062385A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Food or beverage cans made from plastic coated steel sheet
Assignee: Dow Chemical Co
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Filing: 1982-04-01
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Granted: —
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Expires: 2002-04-01
Abstract
Abstract The use of organic solvent-based coating compositions in the preparation of coated steel feedstock for use in the manufacture of retortable draw-redraw food and beverage cans is eliminated by using as such can feedstock a laminated or extrusion coated steel sheet comprising a steel sheet material (e.g., such as electrolytic chrome/chrome oxide coated steel) having adhered to at least one major planar surface thereof a multilayered synthetic thermoplastic resin coating comprising (1) an adhesive synthetic thermoplastic resin inner layer (e.g., such as a layer of a normally solid random ethylene/acrylic acid copolymer) bonded directly to the surface of said steel sheet material and (2) an outer layer of a synthetic thermoplastic polymer resin which has a crystalline melting point of at least about 121 DEG C and which is adhered to said adhesive resin inner layer.
Inventors
- 👤 Martin Keith Hitchcock
- 👤 Craig William Potter
- 👤 Floyd Eugene Romesberg
- 👤 Lyle Wilson Colburn
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 13:53
CPC Classifications
B; B32; B32B; B32B15/00; B32B15/04; B32B15/08; B32B15/18; B32B27/00; B32B27/32; B32B7/00; B32B7/04; B32B7/12; B65; B65D; B65D1/00; B65D1/22; B65D1/26; B65D1/28; B65D25/00; B65D25/14; B32B2255/00; B32B2255/20; B32B2270/00; B32B2310/00; B32B2310/04; B32B2310/0445; B32B2310/0454; B32B2310/08; B32B2310/0875; B32B2310/0887; B32B2323/00; B32B2323/04; B32B2323/043; B32B2439/00; B32B2439/40; B32B2439/66
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
123 words
A drawn food or beverage container body which is made of a laminated or extrusion coated steel sheet comprising a steel sheet having adhered to at least one major surface thereof a multilayered synthetic thermoplastic resin coating comprising an adhesive synthetic thermoplastic resin inner layer which is composed of at least a major proportion of a normally solid random copolymer of ethylene with from 1 to 30 weight percent, based upon said copolymer, of an ethylenically unsaturated carboxylic acid monomer and which copolymer is bonded on one side directly to the surface of said steel sheet and is adhered on its other side to an outer layer of a synthetic thermoplastic polymer resin having a crystalline melting point of at least about 121°C.
Claim 2
Dependent Claim
123 words
A drawn food or beverage container body which is made of a laminated or extrusion coated steel sheet comprising a steel sheet having adhered to at least one major surface thereof a multilayered synthetic thermoplastic resin coating comprising an adhesive synthetic thermoplastic resin inner layer which is composed of at least a major proportion of a normally solid random copolymer of ethylene with from 1 to 30 weight percent, based upon said copolymer, of an ethylenically unsaturated carboxylic acid monomer and which copolymer is bonded on one side directly to the surface of said steel sheet and is adhered on its other side to an outer layer of a synthetic thermoplastic polymer resin having a crystalline melting point of at least about 121°C.
Claim 3
Dependent Claim
15 words
The container body of Claim 1, wherein the steel sheet is chrome/chrome oxide coated steel.
Claim 4
Dependent Claim
42 words
The container body of Claim 1 or 2, wherein the adhesive layer comprises a copolymer of a major proportion of ethylene and from 2 to 20 weight percent, based upon the weight of such copolymer, of an ethylenically unsaturated carboxylic acid monomer.
Claim 5
Dependent Claim
40 words
The container body of Claim 1, 2 or 3, wherein the outer layer comprises a high density polyethylene resin having a density of from 0.950 to 0.965 g/cc and a melt index from 0.05 to 5 or a polyamide resin.
Claim 6
Dependent Claim
60 words
The container body of Claim 1, 2 or 3, wherein the outer layer comprises a blend of a high density polyethylene resin having a melt index of from 0.05 to 3 and a density of from 0.960 to 0.965 g/cc with up to about 30 weight percent based upon the weight of such blend of a low density polyethylene resin.
Claim 7
Dependent Claim
68 words
The container body of Claim 1, 2 or 3, wherein the adhesive layer comprises a copolymer of a major proportion of ethylene with from 2 to 20 weight percent, based upon such copolymer, of acrylic or methacrylic acid, and wherein the outer layer comprises a high density polyethylene resin having melt index of 3 or less and a density of at least about 0.960 or a polyamide resin.
Claim 8
Dependent Claim
41 words
The container body of any one of the preceding Claims, wherein the steel sheet material has a thickness of from 5 to 15 mils, and the multilayered synthetic thermoplastic resin coating has an overall thickness of from 0.2 to 2.8 mils.
Claim 9
Dependent Claim
69 words
The container body of any one of the preceding Claims, which has been post-baked after its formation but prior to its use in food or beverage canning operations at a temperature above the crystalline melting point of the highest melting point resin employed in said thermoplastic resin coating for a period of time sufficient to relieve the stress created in such coating during the formation of said can body.
Claim 10
Dependent Claim
26 words
The container body of any one of Claims 1 to 7, having been exposed to an electron beam irradiation dosage of from 2 to 20 megarads.
Claim 11
Dependent Claim
24 words
A container comprising the container body of any one of the preceding Claims, and a food or beverage hermetically contained within the container body.
Claim 12
Independent Claim
108 words
A method for forming a food or beverage container body, comprising the steps of adhering to at least one planar surface of a steel sheet material the multilayered synthetic thermoplastic resin coating of any one of Claims 1 to 7, forming the resulting coated steel sheet material into said container body via a draw-redraw container forming process, post-baking the coated container body formed by said draw-redraw process at a temperature above the crystalline melting point of the highest melting point resin employed in said thermoplastic resin coating for a period of time sufficient to relieve the stress created in such coating during the formation of said can body.
Claim 13
Dependent Claim
47 words
The method of Claim 11, wherein post-baking of the formed container body takes place in a hot air oven maintained at a temperature of from 149° to 260°C for a period of from 0.2 to 5 minutes prior to its use in food or beverage canning operations.
Claim 14
Independent Claim
90 words
A method for forming a food or beverage container body, comprising the steps of adhering to at least one planar surface of a steel sheet material the multilayered synthetic thermoplastic resin coating of any one of Claims 1 to 7, exposing the coating to an electron beam irradiation dosage of from 2 to 20 megarads either prior to, during or subsequent to, the application of such coatings to said steel sheet material, and forming the resulting coated steel sheet material into said container body via a draw-redraw container forming process.
Claim 15
Dependent Claim
18 words
The process of Claim 13, wherein the electron beam irradiation dosage employed is from 5 to 10 megarads.
Claim 16
Dependent Claim
37 words
The process of Claim 13 or 14, wherein the electron beam irradiation of the coating is conducted prior to the draw-redraw formation of the food or beverage can body from the laminated or extrusion coated steel sheet.
Claim 17
Dependent Claim
33 words
The process of Claim 13 or 14, wherein the electron beam irradiation is conducted on the coating in free film form prior to the application of such coating to the steel sheet material.
Claim 18
Independent Claim
86 words
A method of making draw-redraw food or beverage can bodies comprising the steps of extrusion coating or laminating to both sides of a steel sheet material the multilayered synthetic thermoplastic coating of any one of Claims 1 to 7, irradiating both multilayered thermoplastic coatings either prior, during, or subsequent to the application thereof to the steel sheet material with an electron beam irradiation dosage of from 2 to 20 megarads; and forming the coated metal sheet into a container body via a draw-redraw can forming process.
References Cited (Backward Citations)
No citation records indexed.
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