Patent US5645538A successfully refreshed from Google Patents.
US4421825A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Paperboard coated to minimize browning
Assignee: WestRock Minnesota Corp
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Filing: 1983-05-02
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Granted: 1983-12-20
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Expires: 2003-05-02
Abstract
Abstract The browning of paperboard subjected to temperatures of up to about 205 DEG C. is minimized by applying to the paperboard a first coating comprising titanium dioxide and an acrylic copolymer and one or more over-coatings comprising a clear acrylic copolymer.
Inventors
- 👤 George M. Seiter
- 👤 Curtis H. Broz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:58
CPC Classifications
D; D21; D21H; D21H19/00; D21H19/80; D21H19/82; D21H19/826; B; B65; B65D; B65D65/00; B65D65/38; B65D65/40; B65D65/403; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10T; Y10T428/00; Y10T428/26; Y10T428/28; Y10T428/2839; Y10T428/31504; Y10T428/31855; Y10T428/3188; Y10T428/31895; Y10T428/31906
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
116 words
A paperboard product resistant to browning at temperatures of up to about 205° C., said product comprising a paperboard substrate coated on at least one surface thereof with a plurality of distinct coatings including a first coating comprising titanium dioxide and a solution having from about 5 to 15 weight percent acrylic copolymer, said titanium dioxide being present in said first coating in amounts ranging from about 15 to about 35 weight percent of the acrylic copolymer in the first coating, and one or more overcoatings of a clear acrylic copolymer which is substantially free of titanium dioxide wherein the first coating and the one or more overcoatings have a combined thickness totaling about 0.20 mils.
Claim 2
Dependent Claim
116 words
A paperboard product resistant to browning at temperatures of up to about 205° C., said product comprising a paperboard substrate coated on at least one surface thereof with a plurality of distinct coatings including a first coating comprising titanium dioxide and a solution having from about 5 to 15 weight percent acrylic copolymer, said titanium dioxide being present in said first coating in amounts ranging from about 15 to about 35 weight percent of the acrylic copolymer in the first coating, and one or more overcoatings of a clear acrylic copolymer which is substantially free of titanium dioxide wherein the first coating and the one or more overcoatings have a combined thickness totaling about 0.20 mils.
Claim 3
Dependent Claim
20 words
A paperboard product according to claim 1 in which there are 1 to 2 overcoatings of a clear acrylic copolymer.
Claim 4
Dependent Claim
27 words
A paperboard product according to claim 2 in which the acrylic copolymer in said first coating and in said overcoatings is a copolymer of styrene and methylmethacrylate.
Claim 5
Dependent Claim
25 words
A paperboard product according to claim 1 which additionally comprises, on top of the overcoatings, a release coating comprising an acrylic copolymer and calcium stearate.
Claim 6
Independent Claim
144 words
A method for minimizing the browing of paperboard when said paperboard is subjected to temperatures of up to about 205° C. which comprises applying to at least one surface of the paperboard a first coating comprising titanium dioxide and an acrylic copolymer dissolved in an organic solvent, said acrylic copolymer being about 5 to 15 weight percent of the first coating and the titanium dioxide being present in said first coating in an amount from about 15 to 35 weight percent of the acrylic copolymer in the first coating and, after drying said first coating, applying one or more overcoatings of a clear acrylic copolymer solution which is substantially free of titanium dioxide to the so coated paperboard, with a drying step between each such overcoating wherein the first coating and the one or more overcoatings have a combined thickness totaling about 0.20 mils.
Claim 7
Independent Claim
144 words
A method for minimizing the browing of paperboard when said paperboard is subjected to temperatures of up to about 205° C. which comprises applying to at least one surface of the paperboard a first coating comprising titanium dioxide and an acrylic copolymer dissolved in an organic solvent, said acrylic copolymer being about 5 to 15 weight percent of the first coating and the titanium dioxide being present in said first coating in an amount from about 15 to 35 weight percent of the acrylic copolymer in the first coating and, after drying said first coating, applying one or more overcoatings of a clear acrylic copolymer solution which is substantially free of titanium dioxide to the so coated paperboard, with a drying step between each such overcoating wherein the first coating and the one or more overcoatings have a combined thickness totaling about 0.20 mils.
Claim 8
Independent Claim
19 words
A method according to claims 5 in which 1 to 3 overcoatings of a clear acrylic copolymer are applied.
Claim 9
Dependent Claim
27 words
A method according to claim 6 in which the acrylic copolymer in said first coating and in said overcoatings is a copolymer of styrene and methyl methacrylate.
Claim 10
Dependent Claim
27 words
A method according to claim 5 in which there is additionally applied, on top of the overcoatings, a release coating comprising an acrylic copolymer and calcium stearate.
Claim 11
Dependent Claim
53 words
A paperboard product according to claim 1 wherein said acrylic copolymer is derived from about 10 to about 90 weight percent of esters of acrylic and/or methacrylic acids with alcohols having 1 to 8 carbon atoms and a total of from about 90 to about 10 weight percent of other monomer copolymerizable therewith.
Claim 12
Dependent Claim
45 words
A paperboard product according to claim 1 wherein said first coating has the following composition: ______________________________________
titanium dioxide 17 parts by weight
Styrene-methyl methacrylate
10 parts by weight
copolymer
acetone 50 parts by weight
n-hexane 18 parts by weight
toluene 5 parts by weight
______________________________________
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-19 | 1987-06-20 | 1987-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-19 | 1991-06-20 | 1991-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-19 | 1995-06-20 | 1995-12-20 | $7700.00 | Window Closed / Lapsed |