US3936339A
Expired / Lapsed
US
⏱️ 0.0 years remaining
In-line process for the production of corrugated board
Assignee: International Paper Co
•
Filing: 1973-05-29
•
Granted: 1976-02-03
•
Expires: 1993-05-29
Abstract
Abstract An efficient, inexpensive, in-line process is provided for producing additive-impregnated corrugated board, such as those having excellent rigid-when-wet and rigid-when-humid strengths. The process comprises applying an additive, such as water- and moisture-resistant resin, flame retardant, fire proofing agent, fungicide, mold-inhibitor, insecticide, or the like, in the form of a collapsible foam of a dispersion or solution of the additive to the corrugated medium, and desirably the liners, at the time the corrugated board is being formed.
Inventors
- 👤 James A. Lock
- 👤 Leroy C. Hofmann
- 👤 Chester P. Kulesza
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:37
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/10; B31; B31F; B31F1/00; B31F1/20; B31F1/24; B31F1/26; B31F1/28; B31F1/2804; B31F1/2809; B31F1/2886; B32B27/18; B32B27/42; B32B29/00; B32B29/002; B32B29/007; B32B29/08; B32B5/00; B32B5/18; B32B7/00; B32B7/04; B32B7/12; B32B2307/00; B32B2307/30; B32B2307/306; B32B2307/3065; B32B2307/70; B32B2307/726; B32B2307/7265; B32B2317/00; B32B2317/12; B32B2317/127; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1002; Y10T156/1007; Y10T156/1016; Y10T156/1025; Y10T428/00; Y10T428/31504; Y10T428/31942; Y10T428/31949; Y10T428/31964
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
101 words
An in-line method of making corrugated paperboard with excellent rigid-when-wet strength and having a corrugated medium and at least one liner attached thereto, which method comprises applying to at least one liner or said corrugated medium a rapidly collapsible foam of a dispersion of a water resistant impregnating resin, bringing said corrugated medium and said liner into adhesive contact with each other, heating the resulting composite to complete collapsing of said foam and to thereby complete the impregnation of said medium with said resin, and finally drying said composite after the completion of the collapse of said foam by further heating.
Claim 2
Dependent Claim
101 words
An in-line method of making corrugated paperboard with excellent rigid-when-wet strength and having a corrugated medium and at least one liner attached thereto, which method comprises applying to at least one liner or said corrugated medium a rapidly collapsible foam of a dispersion of a water resistant impregnating resin, bringing said corrugated medium and said liner into adhesive contact with each other, heating the resulting composite to complete collapsing of said foam and to thereby complete the impregnation of said medium with said resin, and finally drying said composite after the completion of the collapse of said foam by further heating.
Claim 3
Dependent Claim
34 words
An in-line method according to claim 1 wherein said dispersion contains an additional additive which is a member selected from the class consisting of resins, flame retardants, fire retardants, mold inhibitors, fungicides, and insecticides.
Claim 4
Dependent Claim
15 words
An in-line method according to claim 2, wherein the additional additive is a fire retardant.
Claim 5
Dependent Claim
15 words
An in-line method according to claim 2, wherein the additional additive is a mold inhibitor.
Claim 6
Dependent Claim
14 words
An in-line method according to claim 2, wherein the additional additive is a fungicide.
Claim 7
Dependent Claim
14 words
An in-line method according to claim 2, wherein the additional additive is an insecticide.
Claim 8
Dependent Claim
26 words
An in-line method according to claim 1, wherein there is also applied to the foam treated medium a defoaming agent to accelerate collapse of the foam.
Claim 9
Dependent Claim
26 words
An in-line method according to claim 1 wherein the resin used is a thermosetting resin selected from the group consisting of phenol-aldehyde, urea-aldehyde, and melamine-aldehyde resins.
Claim 10
Dependent Claim
15 words
An in-line method according to claim 8 wherein the thermosetting resin is a urea-formaldehyde resin.
Claim 11
Dependent Claim
30 words
An in-line method according to claim 1 wherein the resin employed is applied in an amount ranging from about 10 to 30 lbs. per thousand square feet of corrugated board.
Claim 12
Dependent Claim
13 words
An in-line method according to claim 1 wherein the resin is subsequently cured.
Claim 13
Dependent Claim
29 words
A method according to claim 1 wherein the resin employed is applied in an amount ranging from about 16 to 20 lbs. per thousand square feet of corrugated board.
Claim 14
Dependent Claim
30 words
A method according to claim 1 wherein the resin employed is a urea-formaldehyde resin characterized by a mol ratio of about 1.5 and 2.0 to 1 of formaldehyde to urea.
Claim 15
Dependent Claim
22 words
A method according to claim 1 wherein the foam has a density of about 2 lbs. to 8 lbs. per cubic foot.
Claim 16
Dependent Claim
25 words
A method according to claim 1 wherein the corrugated medium having said foam applied is heated to a temperature of between about 300° to 450°F.
Claim 17
Dependent Claim
16 words
A method according to claim 1 wherein the collapsible impregnating foam is applied to the liner.
Claim 18
Dependent Claim
17 words
A method according to claim 1 wherein the collapsible impregnating foam is applied to the corrugating medium.
Claim 19
Dependent Claim
26 words
A method according to claim 1 wherein the foam has a volume of from about 8 to 30 times the original volume of the resin dispersion.
References Cited (Backward Citations)
CA849480A
Cited
US3002873A
Cited
US3025963A
Cited
US3547854A
Cited
GB1039540A
Cited
US3607598A
Cited
US3741854A
Cited
US3796599A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-02 | 1979-08-04 | 1980-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-02 | 1983-08-04 | 1984-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-02 | 1987-08-04 | 1988-02-03 | $7700.00 | Window Closed / Lapsed |