US4543289A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laminated skin-foamed core sandwich structures and method for their preparation
Assignee: Occidental Chemical Corp
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Filing: 1984-12-24
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Granted: 1985-09-24
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Expires: 2004-12-24
Abstract
Abstract Laminated skin-foamed core sandwich structures characterized by an excellent stiffness and load-bearing capability to weight ratio are prepared by heating in a closed mold a sandwich construction that comprises skin layers that comprise a thermoplastic polymer having a glass transition temperature in the range of 75 DEG to 85 DEG C. and reinforcing fibers and a core that comprises a thermoplastic polymer that is compatible with the polymer in the skin layers and that has a glass transition temperature that is 10 DEG to 20 DEG C. lower than that of the polymer in the skin layers and a blowing agent at a temperature sufficient to fuse and expand the core and to fuse the skin layers and bond them to the expanded core.
Inventors
- 👤 Im K. Park
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:12
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/065; B32B7/00; B32B7/02; B32B7/027; B32B27/30; B32B27/304; B32B37/00; B32B37/06; B32B5/00; B32B5/18; B32B2262/00; B32B2262/10; B32B2262/101; B32B2266/00; B32B2266/02; B32B2266/0214; B32B2266/0221; B32B2266/0235; B32B2309/00; B32B2309/02; B32B2309/025; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249987; Y10T428/249988; Y10T428/249991; Y10T428/249992
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
146 words
The method of forming reinforced skin-foamed core sandwich structures that comprises the steps of A. forming a sandwich construction comprising 1. two skin layers, each comprising at least two plies of a thermoplastic polymer composition having a glass transition temperature in the range of 75° to 85° C. and at least one ply of reinforcing fibers, 2. a core composition comprising a thermoplastic polymer composition having a glass transition temperature in the range of 60° to 70° C., said glass transition temperature being 10° to 20° C. lower than that of the resin in the skin layers and said polymer being compatible with that in the skin layers, and a chemical blowing agent, and B. heating said sandwich construction in a closed mold at a temperature sufficient to fuse and expand the core and to fuse the skin layers and bond them to the expanded core.
Claim 2
Independent Claim
146 words
The method of forming reinforced skin-foamed core sandwich structures that comprises the steps of A. forming a sandwich construction comprising 1. two skin layers, each comprising at least two plies of a thermoplastic polymer composition having a glass transition temperature in the range of 75° to 85° C. and at least one ply of reinforcing fibers, 2. a core composition comprising a thermoplastic polymer composition having a glass transition temperature in the range of 60° to 70° C., said glass transition temperature being 10° to 20° C. lower than that of the resin in the skin layers and said polymer being compatible with that in the skin layers, and a chemical blowing agent, and B. heating said sandwich construction in a closed mold at a temperature sufficient to fuse and expand the core and to fuse the skin layers and bond them to the expanded core.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein the thermoplastic polymer in the skin layers has a glass transition temperature of about 80° C.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein the thermoplastic polymer in the skin layers is polyvinyl chloride.
Claim 5
Dependent Claim
26 words
The method of claim 1 wherein the thermoplastic polymer in the core is a vinyl chloride copolymer having a glass transition temperature of about 62° C.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein the thermoplastic polymer in the core is a vinyl chloride-vinyl acetate copolymer.
Claim 7
Dependent Claim
12 words
The method of claim 1 wherein the reinforcing fibers are glass fibers.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein the reinforcing plies are glass fiber mats.
Claim 9
Dependent Claim
12 words
The method of claim 1 wherein the chemical blowing agent comprises azodicarbonamide.
Claim 10
Dependent Claim
26 words
The method of claim 3 wherein the polyvinyl chloride in the skin layers has a melt processing temperature in the range of 160° to 200° C.
Claim 11
Dependent Claim
27 words
The method of claim 5 wherein the vinyl chloride-vinyl acetate copolymer in the core has a melt processing temperature in the range of 135° to 165° C.
Claim 12
Dependent Claim
31 words
The method of claim 1 wherein in step B the sandwich construction is heated to a temperature in the range of 160° to 200° C. for from 5 to 15 minutes.
Claim 13
Dependent Claim
98 words
The method of claim 1 wherein a sandwich structure comprising A. two skin layers, each formed of alternating plies of polyvinyl chloride having a glass transition temperature of about 80° C. and glass fiber mats and B. a cord comprising a vinyl chloride-vinyl acetate copolymer having a glass transition temperature of about 62° C. and a blowing agent is heated in a closed mold at a temperature in the range of 160° to 200° C. for a time sufficient to fuse and expand the core and to fuse the skin layers and bond them to the expanded core.
Claim 14
Dependent Claim
26 words
The method of claim 1 wherein the skin layers are prelaminated by heating the interleafed plies of resin and reinforcing fibers in a mold under pressure.
Claim 15
Dependent Claim
147 words
A reinforced skin-foamed core sandwich structure that is the product obtained by A. forming a sandwich construction comprising 1. two skin layers, each of which comprises at least two plies of a thermoplastic polymer composition having a glass transition temperature in the range of 75° to 85° C. and at least one ply of reinforcing fibers and 2. a core comprising a thermoplastic polymer composition having a glass transition temperature in the range of 60° to 70° C., said glass transition temperature being 10° to 20° C. lower than that of the polymer in the skin layers and said polymer being compatible with the polymer in the skin layers, and a chemical blowing agent and B. heating said sandwich construction in a closed mold at a temperature sufficient to fuse and expand the core and to fuse the skin layers and bond them to the expanded core.
Claim 16
Dependent Claim
147 words
A reinforced skin-foamed core sandwich structure that is the product obtained by A. forming a sandwich construction comprising 1. two skin layers, each of which comprises at least two plies of a thermoplastic polymer composition having a glass transition temperature in the range of 75° to 85° C. and at least one ply of reinforcing fibers and 2. a core comprising a thermoplastic polymer composition having a glass transition temperature in the range of 60° to 70° C., said glass transition temperature being 10° to 20° C. lower than that of the polymer in the skin layers and said polymer being compatible with the polymer in the skin layers, and a chemical blowing agent and B. heating said sandwich construction in a closed mold at a temperature sufficient to fuse and expand the core and to fuse the skin layers and bond them to the expanded core.
Claim 17
Dependent Claim
126 words
The reinforced skin-foamed core sandwich structure defined in claim 14 that is the product obtained by A. forming a sandwich construction that comprises 1. two skin layers, each of which comprises at least two plies of polyvinyl chloride that has a glass transition temperature of about 80° C. and at least one ply of glass fiber mat and 2. a core comprising a vinyl chloride-vinyl acetate copolymer that has a glass transition temperature of about 62° C. and a chemical blowing agent and B. heating said sandwich construction in a closed mold at a temperature in the range of 160° to 200° C. for a time sufficient to fuse and expand the core and to fuse the skin layers and bond them to the expanded core.
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) | 1988-09-23 | 1989-03-25 | 1989-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-23 | 1993-03-25 | 1993-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-23 | 1997-03-25 | 1997-09-24 | $7700.00 | Window Closed / Lapsed |