US4129530A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Soft ethylenic polymer foams
Assignee: Dow Chemical Co
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Filing: 1977-12-19
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Granted: 1978-12-12
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Expires: 1997-12-19
Abstract
Abstract Low density, closed cell, soft foam products having dimensional stability are made from ethylenic resins having low stiffness, especially comprising copolymers consisting essentially of ethylene and monoethylenically unsaturated non-ionic comonomers, by release to lower pressure of a flowable, foamable gel under pressure, e.g., by extrusion foaming, wherein the gel comprises the ethylenic polymer and a volatile mixed blowing agent. The starting polymers are preferably copolymers of ethylene and vinyl acetate having stiffness less than about 20,000 psi. The mixed blowing agents are particularly characterized as mixtures of dichlorodifluoromethane and at least one fluorocarbon constituent A, as defined. Exemplary mixtures contain (I) dichlorodifluoromethane and (II) from 35 to 50 percent chloropentafluoroethane, octafluoropropane or octafluorocyclobutane based on the mixtures of I and II.
Inventors
- 👤 Chung P. Park
- 👤 John M. Corbett
- 👤 Warren H. Griffin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:33
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/14; C08J9/143; C08J9/147; C08J2323/00; C08J2323/02; Y; Y10; Y10S; Y10S264/00; Y10S264/05
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
240 words
A method for making soft ethylenic polymer resin foams having substantially closed cell structure, dimensional stability, and thickness greater than about 0.5 inch from starting ethylenic polymer resins which have low stiffness less than about 20,000 psi and which comprise low stiffness copolymers of ethylene which copolymers consist essentially of ethylene and monoethylenically unsaturated non-ionic comonomers, by forming under heat and pressure a flowable gel composition of the starting polymer resin and a volatile blowing agent and releasing the resulting flowable gel to ambient air atmosphere whereby the blowing agent separates from the gel and forms gas bubbles in the polymer resin, particularly characterized in that the volatile blowing agent is composed of a mixture of dichlorodifluoromethane and an essential constituent A which is at least one fluorocarbon which has normal boiling point between -40° and 5° C. and a value for the critical quantity T b -0.5V c of not greater than 110, where T b is the normal boiling point temperature of the fluorocarbon in degrees Kelvin and V c is its critical volume in cubic centimeters per gram-mole, the mixed blowing agent containing, per 100 parts by weight, from about 35 to about 50 parts of fluorocarbon constituent A and at least about 75 parts of total fluorocarbon mixture of dichlorodifluoromethane and constituent A and there being up to about 0.18 gram-mole of such mixed blowing agent per 100 grams of polymer resin in the flowable gel.
Claim 2
Independent Claim
240 words
A method for making soft ethylenic polymer resin foams having substantially closed cell structure, dimensional stability, and thickness greater than about 0.5 inch from starting ethylenic polymer resins which have low stiffness less than about 20,000 psi and which comprise low stiffness copolymers of ethylene which copolymers consist essentially of ethylene and monoethylenically unsaturated non-ionic comonomers, by forming under heat and pressure a flowable gel composition of the starting polymer resin and a volatile blowing agent and releasing the resulting flowable gel to ambient air atmosphere whereby the blowing agent separates from the gel and forms gas bubbles in the polymer resin, particularly characterized in that the volatile blowing agent is composed of a mixture of dichlorodifluoromethane and an essential constituent A which is at least one fluorocarbon which has normal boiling point between -40° and 5° C. and a value for the critical quantity T b -0.5V c of not greater than 110, where T b is the normal boiling point temperature of the fluorocarbon in degrees Kelvin and V c is its critical volume in cubic centimeters per gram-mole, the mixed blowing agent containing, per 100 parts by weight, from about 35 to about 50 parts of fluorocarbon constituent A and at least about 75 parts of total fluorocarbon mixture of dichlorodifluoromethane and constituent A and there being up to about 0.18 gram-mole of such mixed blowing agent per 100 grams of polymer resin in the flowable gel.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent A of the blowing agent mixture is chloropentafluoroethane.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent A of the blowing agent mixture is octafluorocyclobutane.
Claim 5
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent A of the blowing agent mixture is octafluoropropane.
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent A of the blowing agent mixture is perfluoro-n-butane.
Claim 7
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent A of the blowing agent mixture is perfluoro-iso-butane.
Claim 8
Dependent Claim
35 words
The method according to claim 1 wherein the starting ethylenic polymer resin comprises a copolymer which consists essentially of ethylene and from about 5 to about 45 weight percent vinyl acetate based on the copolymer.
Claim 9
Dependent Claim
16 words
The method of claim 7 wherein the blowing agent is a mixture of dichlorodifluoromethane and chloropentafluoroethane.
Claim 10
Dependent Claim
16 words
The method of claim 7 wherein the blowing agent is a mixture of dichlorodifluoromethane and octafluorocyclobutane.
Claim 11
Dependent Claim
16 words
The method of claim 7 wherein the blowing agent is a mixture of dichlorodifluoromethane and octafluoropropane.
Claim 12
Dependent Claim
16 words
The method of claim 7 wherein the blowing agent is a mixture of dichlorodifluoromethane and perfluoro-n-butane.
Claim 13
Dependent Claim
16 words
The method of claim 7 wherein the blowing agent is a mixture of dichlorodifluoromethane and perfluoro-iso-butane.
Claim 14
Dependent Claim
200 words
As an article of manufacture, a soft ethylenic polymer resin foam having substantially closed cell structure and dimensional stability wherein the ethylenic polymer resin comprises a copolymer of ethylene which copolymer consists essentially of ethylene and monoethylenically unsaturated non-ionic comonomer and has stiffness less than about 20,000 psi, the foam having density from about 1.5 to about 20 pounds per cubic foot and particularly characterized in that the gas space of the foam cells originally consisting essentially of dichlorodifluoromethane and a constituent A which is at least one fluorocarbon which has normal boiling point between -40° and 5° C. and a value for the critical quantity T b -0.5V c not greater than 110 where T b is the normal boiling point temperature in degrees Kelvin of the fluorocarbon and V c is its critical volume in cubic centimeters per gram-mole, the mixed blowing agent containing, per 100 parts by weight, from about 35 to about 50 parts of fluorocarbon constituent A and at least about 75 parts of total fluorocarbon mixture of dichlorodifluoromethane and constituent A and there being up to about 0.18 gram-mole of such mixed blowing agent per 100 grams of polymer resin in the flowable gel.
Claim 15
Dependent Claim
200 words
As an article of manufacture, a soft ethylenic polymer resin foam having substantially closed cell structure and dimensional stability wherein the ethylenic polymer resin comprises a copolymer of ethylene which copolymer consists essentially of ethylene and monoethylenically unsaturated non-ionic comonomer and has stiffness less than about 20,000 psi, the foam having density from about 1.5 to about 20 pounds per cubic foot and particularly characterized in that the gas space of the foam cells originally consisting essentially of dichlorodifluoromethane and a constituent A which is at least one fluorocarbon which has normal boiling point between -40° and 5° C. and a value for the critical quantity T b -0.5V c not greater than 110 where T b is the normal boiling point temperature in degrees Kelvin of the fluorocarbon and V c is its critical volume in cubic centimeters per gram-mole, the mixed blowing agent containing, per 100 parts by weight, from about 35 to about 50 parts of fluorocarbon constituent A and at least about 75 parts of total fluorocarbon mixture of dichlorodifluoromethane and constituent A and there being up to about 0.18 gram-mole of such mixed blowing agent per 100 grams of polymer resin in the flowable gel.
Claim 16
Dependent Claim
58 words
An article of manufacture according to claim 13 wherein the ethylenic polymer foam has density from about 1.5 to about 6 pounds per cubic foot, and the ethylenic polymer resin is a copolymer which consists essentially of ethylene and from about 10 to about 45 weight percent vinyl acetate, which copolymer has stiffness less than about 10,000 psi.
References Cited (Backward Citations)
US3766099A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-12-11 | 1982-06-12 | 1982-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-11 | 1986-06-12 | 1986-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-11 | 1990-06-12 | 1990-12-12 | $7700.00 | Window Closed / Lapsed |