Patent US3935358A successfully refreshed from Google Patents.
US3935358A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing a hollow, rib-reinforced laminated structure
Assignee: EIDP Inc
•
Filing: 1974-02-15
•
Granted: 1976-01-27
•
Expires: 1994-02-15
Abstract
Abstract The invention provides a process for preparing a hollow, rib-reinforced, laminated article by: A. placing two sheets between opposing mold platens, the sheets being aligned such that the sheet surfaces oppose each other, at least one of the sheets being a thermoplastic material heated to its thermoforming temperature and at least one of the sheets being provided with grooves or integral projections which form fluid passageways, and at least one of the mold platens being provided with a mold caivty to form a shaped article having ribs; B. closing the mold platens to contact the sheets; and C. introducing a fluid into the fluid passageways to distend the thermoplastic sheet into its mold cavity forming a shaped article having ribs, while the sheets maintain contact in the nondistended areas.
Inventors
- 👤 Nathaniel Convers Wyeth
- 👤 Frank William Arnoth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:04
CPC Classifications
B; B32; B32B; B32B3/00; B32B3/26; B32B3/30; B32B27/00; B29; B29C; B29C49/00; B29C49/02; B29C49/06905; B29C49/0691; B32B27/06; B32B27/08; B32B27/18; B32B27/20; B32B27/32; B29C2791/00; B29C2791/004; B29C2791/006; B32B2315/00; B32B2315/16; B32B2323/00; B32B2323/04; B32B2323/10; B32B37/00; B32B37/14; B32B37/15; B32B37/153; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24479; Y10T428/24562; Y10T428/2457
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
170 words
A process for preparing a hollow, ribreinforced, laminated article consisting essentially of: a. placing two sheets between opposing mold platens, the sheets being aligned such that the sheet surfaces are in interfacial contact, at least one of the sheets being a thermoplastic material heated to its thermoforming temperature and at least one of the sheets being provided with grooves or integral projections, on the surface which contacts the other sheet, which form fluid passageways, and at least one of the mold platens being provided with a mold cavity to form a shaped article having ribs; b. closing the mold platens to contact the sheets and position the mold cavity contiguous to the thermoplastic sheet which is at its thermoforming temperature; c. introducing a fluid into the fluid passageways to distend the thermoplastic sheet into its mold cavity forming a shaped article having ribs, while the closed mold platens maintain contact between the sheets in the nondistended areas; and (d) adhering the sheets in the nondistended areas to form a laminate.
Claim 2
Dependent Claim
170 words
A process for preparing a hollow, ribreinforced, laminated article consisting essentially of: a. placing two sheets between opposing mold platens, the sheets being aligned such that the sheet surfaces are in interfacial contact, at least one of the sheets being a thermoplastic material heated to its thermoforming temperature and at least one of the sheets being provided with grooves or integral projections, on the surface which contacts the other sheet, which form fluid passageways, and at least one of the mold platens being provided with a mold cavity to form a shaped article having ribs; b. closing the mold platens to contact the sheets and position the mold cavity contiguous to the thermoplastic sheet which is at its thermoforming temperature; c. introducing a fluid into the fluid passageways to distend the thermoplastic sheet into its mold cavity forming a shaped article having ribs, while the closed mold platens maintain contact between the sheets in the nondistended areas; and (d) adhering the sheets in the nondistended areas to form a laminate.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein both sheets are a thermoplastic material.
Claim 4
Dependent Claim
13 words
The process of claim 2 wherein the thermoplastic material is polyethylene or polypropylene.
Claim 5
Dependent Claim
13 words
The process of claim 2 wherein both sheets are distended in step (c).
Claim 6
Dependent Claim
15 words
The process of claim 2 wherein fluid is introduced into the fluid passageways under pressure.
Claim 7
Dependent Claim
11 words
The process of claim 5 wherein the fluid is heated air.
Claim 8
Dependent Claim
13 words
The process of claim 6 wherein a vacuum is drawn in the mold.
Claim 9
Dependent Claim
23 words
The process of claim 2 wherein the projections of the sheet are ridges having a width less than the thickness of the sheet.
Claim 10
Dependent Claim
22 words
The process of claim 1 wherein, in step (d), the mold platens are further closed to seal nondistended portions of the sheets.
Claim 11
Dependent Claim
12 words
The process of claim 9 wherein both sheets are a thermoplastic material.
Claim 12
Dependent Claim
22 words
The process of claim 10 wherein a composite preform of two thermoplastic sheets is placed between the mold platens in step (a).
Claim 13
Dependent Claim
20 words
The process of claim 11 wherein one of the thermoplastic sheets has projections and the other thermoplastic sheet is smooth.
Claim 14
Dependent Claim
11 words
The process of claim 11 wherein both thermoplastic sheets have projections.
Claim 15
Dependent Claim
13 words
The process of claim 11 wherein both sheets are distended in step (c).
Claim 16
Dependent Claim
16 words
The process of claim 11 wherein fluid is introduced into the fluid passageways under positive pressure.
Claim 17
Dependent Claim
11 words
The process of claim 15 wherein the fluid is heated air.
Claim 18
Dependent Claim
19 words
The process of claim 11 wherein the preform is heated by placing the preform between two opposing hot platens.
Claim 19
Dependent Claim
17 words
The process of claim 11 wherein the preform is heated by subjecting the preform to radiant heat.
Claim 20
Dependent Claim
13 words
The process of claim 11 including the step of heating the mold platens.
Claim 21
Dependent Claim
19 words
The process of claim 11 wherein fluid is introduced into the preform passageways through at least one marginal edge.
Claim 22
Dependent Claim
34 words
The process of claim 11 wherein the fluid is introduced into the preform passageways by drawing a vacuum in the mold to draw the fluid into the passageways through at least one marginal edge.
Claim 23
Dependent Claim
12 words
The process of claim 21 wherein the fluid is introduced under pressure.
Claim 24
Dependent Claim
11 words
The process of claim 22 wherein the fluid is heated air.
Claim 25
Dependent Claim
77 words
The process of claim 11 wherein the opposing mold platens are closed on the preform with the mold platens spaced apart a distance equivalent to about the thickness of the preform and said mold platens remain in this position until the thermoplastic article has been formed by introducing a fluid into the fluid passages of the preform whereupon the opposing mold platens are closed an incremental amount sufficient to pressure seal the nondistended areas of the preform.
Claim 26
Dependent Claim
11 words
The process of claim 11 wherein the thermoplastic material is polyethylene.
Claim 27
Dependent Claim
11 words
The process of claim 11 wherein the thermoplastic material is polypropylene.
Claim 28
Dependent Claim
34 words
The process of claim 11 wherein the thermoplastic contains an inert filler material in the amount of about 1 to 70 weight percent based on the total weight of the polymer and filler present.
Claim 29
Dependent Claim
32 words
The process of claim 11 wherein the thermoplastic contains a filler material of clay in the amount of about 30 to 60 weight percent based on the weight of the polymer present.
Claim 30
Dependent Claim
48 words
The process of claim 11 wherein the fluid passages on an interfacial surface of the preform is made up of a pattern which in cross section consists of trapezoidal-shaped protuberances extending in a continuous parallel pattern across the width of the sheet with trapezoidal valleys between the protuberances.
Claim 31
Dependent Claim
14 words
The process of claim 11 wherein the fluid passages in the preform are interconnected.
Claim 32
Dependent Claim
16 words
The process of claim 11 wherein the thermoplastic sheets of the preform are adhesively bonded together.
Claim 33
Dependent Claim
23 words
The process of claim 11 wherein the projections of the sheet are ridges having a width less than the thickness of the sheet.
Claim 34
Dependent Claim
11 words
The process of claim 11 wherein the mole is vertically aligned.
Claim 35
Dependent Claim
12 words
A hollow, rib-reinforced, laminated article made by the process of claim 1.
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) | 1979-01-26 | 1979-07-28 | 1980-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-26 | 1983-07-28 | 1984-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-26 | 1987-07-28 | 1988-01-27 | $7700.00 | Window Closed / Lapsed |