US4101467A
Expired / Lapsed
US
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Soft ethylenic polymer foams
Assignee: Dow Chemical Co
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Filing: 1977-01-27
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Granted: 1978-07-18
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Expires: 1997-01-27
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 stating 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 at least one fluorocarbon constituent I and at least one fluorocarbon constituent II, as defined. Exemplary mixtures contain (I) 1,2-dichloro-1,1,2,2-tetrafluoroethane and (II) from 25 to 50 percent chloropentafluoroethane, octafluoropropane or octafluorocyclobutane based on the mixtures of I and II.
Inventors
- 👤 Chung Poo Park
- 👤 Warren H. Griffin
- 👤 John M. Corbett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:37
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/14; C08J9/143; C08J9/147; C08J2323/00; C08J2323/02; C08J2323/04; C08J2323/08; Y; Y10; Y10S; Y10S264/00; Y10S264/05
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
286 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 an essential constituent I which is at least one fluorocarbon which has normal boiling point between -25° and 20° C, from 2 to 4 carbon atoms in its molecular structure, and a value for the critical quantity T b -0.5V c of not less than 125 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, and an essential constituent II which is at least one fluorocarbon which has normal boiling point between -40° and 5° C and a value for its critical quantity T b -0.5V c as above defined of not greater than 110, the mixed blowing agent containing, per 100 parts by weight, from about 10 to about 50 parts of fluorocarbon constituent II and at least about 75 parts of total fluorocarbon constituents I and II, 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
286 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 an essential constituent I which is at least one fluorocarbon which has normal boiling point between -25° and 20° C, from 2 to 4 carbon atoms in its molecular structure, and a value for the critical quantity T b -0.5V c of not less than 125 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, and an essential constituent II which is at least one fluorocarbon which has normal boiling point between -40° and 5° C and a value for its critical quantity T b -0.5V c as above defined of not greater than 110, the mixed blowing agent containing, per 100 parts by weight, from about 10 to about 50 parts of fluorocarbon constituent II and at least about 75 parts of total fluorocarbon constituents I and II, 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
27 words
The method of claim 1 wherein the mixed blowing agent containing, per 100 parts by weight, from about 15 to about 50 parts of fluorocarbon constituent II.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent I of the blowing agent mixture is 1,2,-dichloro-1,1,2,2-tetrafluoroethane.
Claim 5
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent I of the blowing agent mixture is 1,1,1-trifluoropropane.
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent I of the blowing agent mixture is 1,1-difluoroethane.
Claim 7
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent I of the blowing agent mixture is 1,1,2,2-tetrafluoroethane.
Claim 8
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent II of the blowing agent mixture is chloropentafluoroethane.
Claim 9
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent II of the blowing agent mixture is octafluorocyclobutane.
Claim 10
Dependent Claim
17 words
The method of claim 1 wherein the fluorocarbon constituent II of the blowing agent mixture is octafluoropropane.
Claim 11
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 12
Dependent Claim
16 words
The method of claim 10 wherein the blowing agent is a mixture of 1,2-dichloro-1,1,2,2-tetrafluoroethane and chloropentafluoroethane.
Claim 13
Dependent Claim
16 words
The method of claim 10 wherein the blowing agent is a mixture of 1,2-dichloro-1,1,2,2-tetrafluoroethane and octafluorocyclobutane.
Claim 14
Dependent Claim
16 words
The method of claim 10 wherein the blowing agent is a mixture of 1,1,1-trifluoropropane and octafluorocyclobutane.
Claim 15
Dependent Claim
16 words
The method of claim 10 wherein the blowing agent is a mixture of 1,1-difluoroethane and octafluorocyclobutane.
Claim 16
Dependent Claim
16 words
The method of claim 10 wherein the blowing agent is a mixture of 1,1,2,2-tetrafluoroethane and octafluorocyclobutane.
Claim 17
Dependent Claim
16 words
The method of claim 10 wherein the blowing agent is a mixture of 1,2-dichloro-1,1,2,2-tetrafluoroethane and octafluoropropane.
Claim 18
Dependent Claim
16 words
The method of claim 10 wherein the blowing agent is a mixture of 1,1,1-trifluoropropane and octafluoropropane.
Claim 19
Dependent Claim
16 words
The method of claim 10 wherein the blowing agent is a mixture of 1,1-difluoroethane and octafluoropropane.
Claim 20
Dependent Claim
16 words
The method of claim 10 wherein the blowing agent is a mixture of 1,1,2,2-tetrafluoroethane and octafluoropropane.
Claim 21
Dependent Claim
193 words
As an article of manufacture, a soft ethylenic polymer resin foam having substantially closed cell structure, dimensional stability, and thickness greater than about 0.5 inch 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 a constituent I which is at least one fluorocarbon which has normal boiling point between -25° and 20° C, from 2 to 4 carbon atoms in its molecular structure and a value for the critical quantity T b -0.5V c not less than 125 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, and a constituent II which is at least one fluorocarbon which has normal boiling point between -40° and 5° C and a value for its critical quantity T b -0.5V c as above defined not greater than 110.
Claim 22
Dependent Claim
193 words
As an article of manufacture, a soft ethylenic polymer resin foam having substantially closed cell structure, dimensional stability, and thickness greater than about 0.5 inch 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 a constituent I which is at least one fluorocarbon which has normal boiling point between -25° and 20° C, from 2 to 4 carbon atoms in its molecular structure and a value for the critical quantity T b -0.5V c not less than 125 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, and a constituent II which is at least one fluorocarbon which has normal boiling point between -40° and 5° C and a value for its critical quantity T b -0.5V c as above defined not greater than 110.
Claim 23
Dependent Claim
58 words
An article of manufacture according to claim 20 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)
US3449268A
Cited
US3766099A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-17 | 1982-01-16 | 1982-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-17 | 1986-01-16 | 1986-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-17 | 1990-01-16 | 1990-07-18 | $7700.00 | Window Closed / Lapsed |