US3708333A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing on impregnated waterlaid sheet and resultant product
Assignee: 3M Co
•
Filing: 1970-10-08
•
Granted: 1973-01-02
•
Expires: 1990-10-08
Abstract
Abstract A leatherlike sheet material having a low apparent density (high void volume), good internal bond strength, and a slow rate of water pickup is provided by forming a waterlaid sheet containing leather fiber, impregnating the waterlaid sheet with an uncured polyurethane, polyurethane-urea, or polyurea elastomeric resin system, and permitting the uncured resin system to cure in situ. The uncured resin system should be mixed together and quickly brought into contact with the waterlaid sheet, so that little, if any, curing occurs prior to the impregnation step.
Inventors
- 👤 R Carlson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:06
CPC Classifications
D; D06; D06M; D06M15/00; D06M15/19; D06M15/37; D06M15/564; C; C08; C08L; C08L75/00; C08L75/04; D04; D04H; D04H1/00; D04H1/40; D04H1/58; D04H1/64; Y; Y10; Y10S; Y10S428/00; Y10S428/904
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
59 words
mixing together a curable liquid impregnant system comprising a. a polyisocyanate, b. a compound containing a polymeric chain selected from the group consisting of a polyester chain and a polyoxyalkylene chain, said compound further containing at least two active hydrogen-bearing substituents, and c. a chain propogating agent containing at least two active hydrogen-bearing substituents, and d. an organic solvent,
Claim 2
Dependent Claim
18 words
A process according to claim 1 wherein said impregnating is commenced less than 10 minutes after said mixing.
Claim 3
Dependent Claim
12 words
An impregnated fibrous sheet made according to the process of claim 1.
Claim 4
Dependent Claim
21 words
impregnating said fibrous sheet uniformly throughout its thickness with said curable liquid impregnant system less than 2 hours after said mixing,
Claim 5
Dependent Claim
51 words
substantially preventing loss of said solvent from said curable liquid impregnant system and from said fibrous sheet at least until said curable liquid impregnant system has cured in situ in said fibrous sheet to a stage at which said curable liquid impregnant system has become a substantially immobile, gel-like solid, and
Claim 6
Dependent Claim
11 words
removing said solvent by evaporation after said step (4) is completed.
References Cited (Backward Citations)
BE511423A
Cited
US2774687A
Cited
US2769712A
Cited
US2723935A
Cited
US3116200A
Cited
US2977330A
Cited
US3102835A
Cited
US3282726A
Cited
US3296016A
Cited
US3384506A
Cited
US3436303A
Cited
US3519478A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-02 | 1976-07-03 | 1977-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-02 | 1980-07-03 | 1981-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-02 | 1984-07-03 | 1985-01-02 | $7700.00 | Window Closed / Lapsed |