US4526831A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for thermoforming reinforced polymer sheets
Assignee: Individual
•
Filing: 1984-02-07
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Granted: 1985-07-02
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Expires: 2004-02-07
Abstract
Abstract Reinforced poly(ethylene terephthalate) sheets are thermoformed to articles having one or more surfaces in contact with the mold of such a degree of smoothness that they virtually completely replicate the mold face. When the mold face is completely smooth, the concave imperfections caused by air entrapment in the plastic material account for less than 6% of the surface area. Composite articles consisting of a face member and a backing member are made by thermoforming in a single mold a face member having one or more surfaces in contact with the mold face of such a degree of smoothness that it completely replicates the mold face, and its proportion of concave imperfections is less than about 6% of the surface area. The backing member is bonded in the mold with an adhesive to the face member, and the composite structure is allowed to remain in the mold for a sufficient time to permit subsequent removal without distortion. The initial polymer sheets are less than about 5% crystalline, but the thermoformed article is left in the mold until it crystallizes to the desired degree.
Inventors
- 👤 Edward Hatchadoorian
- 👤 George J. Ostapchenko
- 👤 James L. Patton
- 👤 Harlan S. Young
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:37
CPC Classifications
B; B29; B29C; B29C51/00; B29C51/002; B29C43/00; B29C43/02; B29C43/20; B29C43/203; B29C51/006; B29C51/26; B29C51/42; B29C51/426; B60; B60R; B60R13/00; B60R13/02; B60R13/0212; B60R13/0225; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249924; Y10T428/24994; Y10T428/24995; Y10T428/31504; Y10T428/31551; Y10T428/31616
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
118 words
An article thermoformed from a poly(ethylene terephthalate) sheet reinforced with glass fibers, which fibers are present in an amount within the range of about 5-50% by weight of the sheet composition, said thermoformed article having been thermoformed at a draw ratio of less than about 1.8, defined as the ratio of the initial thickness of the poly(ethylene terephthalate) sheet to the minimum wall thickness of the article, said article having without any further treatment at least one surface having an average roughness, R A , of about 0.1-0.8 μm, and a concave optical imperfection index of less than about 6% of the surface area as determined by image analysis using a microscope having a magnification of 70 times.
Claim 2
Dependent Claim
118 words
An article thermoformed from a poly(ethylene terephthalate) sheet reinforced with glass fibers, which fibers are present in an amount within the range of about 5-50% by weight of the sheet composition, said thermoformed article having been thermoformed at a draw ratio of less than about 1.8, defined as the ratio of the initial thickness of the poly(ethylene terephthalate) sheet to the minimum wall thickness of the article, said article having without any further treatment at least one surface having an average roughness, R A , of about 0.1-0.8 μm, and a concave optical imperfection index of less than about 6% of the surface area as determined by image analysis using a microscope having a magnification of 70 times.
Claim 3
Dependent Claim
19 words
The article of claim 1 wherein the fibers have an average length to diameter ratio of at least 10.
Claim 4
Dependent Claim
21 words
The article of claim 1 wherein the amount of glass fibers in the reinforced polymer composition is about 10-35 weight percent.
Claim 5
Dependent Claim
131 words
An article of claim 1 wherein the reinforced polymer composition also contains another polymer material selected from the group consisting of dipolymers of ethylene with an unsaturated carboxylic acid, terpolymers of ethylene with an unsaturated carboxylic acid and an ester of an unsaturated carboxylic acid, and terpolymers of ethylene with an unsaturated carboxylic acid, and a vinyl ester, the proportion of the carboxylic acid in the dipolymers being about 2-20 weight percent, and the respective proportions of the carboxylic acid and of the ester in the dipolymers being about 1-30 weight percent of each; and the amount of the dipolymer or terpolymer being about 1-20% based on the weight of the reinforced polymer composition, with the proviso that the carboxylic groups may be completely or partially neutralized with divalent metal ions.
Claim 6
Dependent Claim
20 words
The article of claim 4, wherein the carboxylic groups are partially or completely neutralized with zinc, magnesium, or calcium ions.
Claim 7
Dependent Claim
21 words
The article of claim 3 wherein the proportion of the dipolymer or terpolymer in the reinforced polymer composition is about 3-10%.
Claim 8
Dependent Claim
151 words
An article having a face member and a backing member adhesively bonded to the face member, each member being thermoformed from a sheet of a poly(ethylene terephthalate) composition reinforced with a mineral filler, the face member having been thermoformed at a draw ratio of less than about 1.8, defined as the ratio of the initial thickness of the poly(ethylene terephthalate) sheet to the minimum wall thickness of the face member, said face member having without any further treatment at least one surface having an average roughness, R A , of about 0.1-0.8 μm, and a concave optical imperfection index of less than about 6% of the surface area, as determined by image analysis using a microscope having a magnification of 70 times; with the proviso the mineral filler in the face member is glass fibers, and the amount of the glass fibers is about 5-50% by weight of the sheet composition.
Claim 9
Dependent Claim
151 words
An article having a face member and a backing member adhesively bonded to the face member, each member being thermoformed from a sheet of a poly(ethylene terephthalate) composition reinforced with a mineral filler, the face member having been thermoformed at a draw ratio of less than about 1.8, defined as the ratio of the initial thickness of the poly(ethylene terephthalate) sheet to the minimum wall thickness of the face member, said face member having without any further treatment at least one surface having an average roughness, R A , of about 0.1-0.8 μm, and a concave optical imperfection index of less than about 6% of the surface area, as determined by image analysis using a microscope having a magnification of 70 times; with the proviso the mineral filler in the face member is glass fibers, and the amount of the glass fibers is about 5-50% by weight of the sheet composition.
Claim 10
Dependent Claim
19 words
The article of claim 7 wherein the face member is thermoformed at a draw ratio of at most 1.3.
Claim 11
Dependent Claim
17 words
The article of claim 7 wherein the backing member has the same composition as the face member.
Claim 12
Dependent Claim
20 words
The article of claim 9 wherein the average length to diameter ratio of the glass fibers is at least 10.
Claim 13
Dependent Claim
20 words
The article of claim 9 wherein the amount of glass fibers in the poly(ethylene terephthalate) composition is 10-35% by weight.
Claim 14
Dependent Claim
115 words
The article of claim 7 wherein the poly(ethylene terephthalate) sheet material also contains another polymeric material selected from the group consisting of dipolymers of ethylene with an unsaturated carboxylic acid, terpolymers of ethylene with an unaturated carboxylic acid and an ester of an unsaturated carboxylic acid, and terpolymers of ethylene with an unsaturated carboxylic acid and a vinyl ester, the proportion of the carboxylic acid in the dipolymers being about 2-20 weight percent, and the respective proportions of the carboxylic acid and of the ester in the terpolymers being about 1-30 weight percent of each; and the amount of the dipolymer or terpolymer being about 1-20% based on the weight of the reinforced polymer composition.
Claim 15
Dependent Claim
20 words
The article of claim 12, wherein the carboxylic groups are partially or completely neutralized with zinc, magnesium, or calcium ions.
Claim 16
Dependent Claim
24 words
The article of claim 13 wherein the amount of the dipolymer or terpolymer is 3-10% based on the weight of the reinforced polymer composition.
Claim 17
Dependent Claim
32 words
An article of claim 1 selected from the class consisting of automotive parts, aircraft parts, construction elements, marine parts, appliance parts, food service trays, sanitary articles, solar collectors, equipment housings, and furniture.
Claim 18
Dependent Claim
19 words
An article of claim 2 made of a composition containing a filler having an aspect ratio of about 10-35.
Claim 19
Dependent Claim
11 words
An article of claim 16 wherein the filler is glass fibers.
Claim 20
Dependent Claim
10 words
An article of claim 17 which is an automotive part.
Claim 21
Dependent Claim
10 words
An article of claim 17 which is an aircraft part.
Claim 22
Dependent Claim
10 words
An article of claim 17 which is a marine part.
Claim 23
Dependent Claim
10 words
An article of claim 17 which is a construction element.
Claim 24
Dependent Claim
11 words
An article of claim 17 which is a food service tray.
Claim 25
Dependent Claim
10 words
An article of claim 17 which is a sanitary article.
Claim 26
Dependent Claim
10 words
An article of claim 17 which is a solar collector.
Claim 27
Dependent Claim
10 words
An article of claim 17 which is an equipment housing.
Claim 28
Dependent Claim
11 words
An article of claim 17 which is an article of furniture.
Claim 29
Dependent Claim
32 words
An article of claim 7 selected from the class consisting of automotive parts, aircraft parts, construction elements, marine parts, appliance parts, food service trays, sanitary articles, solar collectors, equipment housings, and furniture.
Claim 30
Dependent Claim
19 words
An article of claim 27 made of a composition containing a filler having an aspect ratio of about 10-35.
Claim 31
Dependent Claim
11 words
An article of claim 28 wherein the filler is glass fibers.
Claim 32
Dependent Claim
10 words
An article of claim 29 which is an automotive part.
Claim 33
Dependent Claim
10 words
An article of claim 29 which is an aircraft part.
Claim 34
Dependent Claim
10 words
An article of claim 29 which is a marine part.
Claim 35
Dependent Claim
10 words
An article of claim 29 which is a construction element.
Claim 36
Dependent Claim
11 words
An article of claim 29 which is a food service tray.
Claim 37
Dependent Claim
10 words
An article of claim 29 which is a sanitary article.
Claim 38
Dependent Claim
10 words
An article of claim 29 which is a solar collector.
Claim 39
Dependent Claim
10 words
An article of claim 29 which is an equipment housing.
Claim 40
Dependent Claim
11 words
An article of claim 29 which is an article of furniture.
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) | 1988-07-01 | 1988-12-31 | 1989-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-01 | 1992-12-31 | 1993-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-01 | 1996-12-31 | 1997-07-02 | $7700.00 | Window Closed / Lapsed |