Polymer foams containing gas barrier resins

• US 5,532,284 A
• Filed: 02/17/1995
• Issued: 07/02/1996
• Est. Priority Date: 03/23/1990
• Status: Expired due to Term

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Hammel, Howard S., Creazzo, Joseph A., Bartlett, Philip L.
• Primary Examiner(s): Nutter, Nathan M.
• Assistant Examiner(s): COONEY, JOHN M
• Application Number:
  US08/390,911
• Time in Patent Office: 501 Days
• Field of Search: 521/134, 521/131, 521/137, 521/142, 521/155
• US Class Current: 521/134
• CPC Class Codes: C08J 2205/052 Closed cells, i.e. more than 50% of the pores are closed
• CPC Class Codes: C08J 9/0061 characterized by the use of several polymeric components
• CPC Class Codes: C08J 9/14 organic

Abstract

An improved closed cell polymer foam and foaming agent involving the use of a halocarbon blowing agent (e.g., HCFC-22, HCFC-123, HCFC-123a, and HCFC-141b) in combination with an effective amount of a gas barrier resin (e.g., an ethylene/vinyl acetate copolymer, ethylene/acrylic ester copolymer or acrylic ester polymer) uniformly dispersed in the continuous polymeric phase. The presence of the gas barrier resin is shown to significantly reduce the escape of blowing agent from and/or entry of air into the foam resulting in low thermal conductivity over a longer period of time and improved thermal insulation value.

Claims

1. In a closed cell thermoplastic or thermoset polymer foam characterized by a continuous polymeric phase and discontinuous gaseous phase, the improvement comprising:

an effective amount of a gas barrier resin substantially uniformly dispersed in the continuous polymeric phase which reduces the permeability of the foam;

thereby maintaining a blowing agent in the cells of the foam wherein said blowing agent comprises at least one member from the group consisting of HCFC-22, HCFC-142b, methyl formate, C₃ to C₆ hydrocarbons, HFC-143a, HFC-152, HFC-152a, CO₂, HFC-32, HFC-125, HFC-134, and HFC-134a, wherein said continuous polymeric phase comprises a material selected from the group consisting of polyurethanes, polyisocyanurates, and polystyrene, and;

wherein said gas barrier resin comprises a material selected from the group consisting of;

ethylene/vinyl alcohol copolymers;

polyvinyl alcohol;

polyacrylonitrile and copolymers;

polyvinylidene fluoride;

polyamides;

admixtures of ethylene/vinyl alcohol copolymers and mica; and

mixtures thereof.

2. An improved closed cell thermoplastic or thermoset polymer foam of claim 1 wherein said gas barrier resin is present in the range of from about 0.1 to about 20 weight percent of said foam.

3. An improved closed cell thermoplastic or thermoset polymer foam of claim 1 wherein said gaseous phase comprises a blowing agent gas selected from the group consisting of:

CFCl₃ ;

CF₂ Cl₂ ;

CCl₂ FCClF₂ ;

CClF₂ CClF₂ ;

CHClF₂ ;

CF₃ CHCl₂ ;

CClF₂ CHClF;

CF₃ CHClF;

CCl₂ FCH₃ ;

CClF₂ CH₃ ;

CH₂ F₂ ;

CF₃ CHF₂ ;

CHF₂ CHF₂ ;

CF₃ CH₂ F;

CH₂ FCH₂ F;

CF₃ CH₃ ;

CHF₂ CH₃ ;

CO₂ ;

C₃ to C₆ hydrocarbons;

methyl formate; and

mixtures thereof.

10. The foam of claim 1 or 5 wherein said blowing agent comprises HFC-134a.

11. The foam of claim 1 or 5 wherein said blowing agent comprises HFC-152a.

14. The foam of claim 1 or 5 wherein said blowing agent comprises 1,1,2,2-Tetrafluoroethane.

4. In a process for manufacturing an insulating closed-cell polymer foam wherein a blowing agent is admixed with a molten thermoplastic or a liquid thermoset resin precursor and allowed to expand forming a polymer foam as the polymeric phase solidifies, the improvement comprising the step of:

dispersing in said molten thermoplastic or liquid thermoset resin precursor an effective amount of a gas barrier resin, prior to expansion, such that said gas barrier resin is substantially uniformly dispersed in the resulting polymeric phase of the polymer foam, wherein the gas barrier resin reduces the gas permeability of the polymer foam;

wherein said blowing agent comprises at least one member from the group consisting of HCFC-22, HCFC-142b, methyl formate, C₃ to C₆ hydrocarbons, HFC-143a, HFC-152, HFC-152a, CO₂, HFC-32, HFC-125, HFC-134, and HFC134a, wherein said polymeric phase comprises a material selected from the group consisting of polyurethanes, polyisocyanurates, and polystyrene said gas barrier resin comprises a material selected from the group consisting of;

ethylene/vinyl alcohol copolymers;

polyvinyl alcohol;

polyacrylonitrile and copolymers;

polyvinylidene fluoride;

polyamides;

admixtures of ethylene/vinyl alcohol copolymers and mica; and

mixtures thereof, and;

wherein said gas barrier resin agent is present in the range of from about 0.1 to about 20 weight percent of said foam.

12. The process of claim 4 wherein said blowing agent comprises HFC-134a.

13. The process of claim 4 wherein said blowing agent comprises HFC-152a.

15. The process of claim 4 wherein said blowing agent comprises 1,1,2,2-Tetrafluoroethane.

5. In a closed cell thermoplastic or thermoset polymer foam characterized by a continuous polymeric phase and discontinuous gaseous phase, the improvement comprising:

(a) a gaseous phase comprising at least one blowing agent;

(b) a continuous polymeric phase comprising a material selected from the group consisting of;

polyurethanes, polyisocyanurates, and polystyrene; and

(c) an effective amount of a gas barrier resin substantially uniformly dispersed in the continuous polymeric phase, which reduces the permeability of the foam;

thereby maintaining said blowing agent, which has a lower vapor thermal conductivity than air, in the cells of the foam, wherein said blowing agent comprises at least one member from the group consisting of HCFC-22, HCFC-142b, methyl formate, C₃ to C₆ hydrocarbons, HFC-143a, HFC-152, HFC-152a, CO₂, HFC-32, HFC-125, HFC-134, and HFC-134a, wherein said gas barrier resin comprises at least one material selected from the group consisting of;

ethylene/vinyl alcohol copolymers;

polyvinyl alcohol;

polyacrylonitrile and copolymers;

polyvinylidene fluoride;

polyamides;

admixtures of ethylene/vinyl alcohol

copolymers and mica; and

mixtures thereof.

6. An improved closed cell thermoplastic or thermoset polymer foam of claim 5 wherein said gaseous phase comprises a blowing agent gas selected from the group consisting of:

CFCl₃ ;

CF₂ Cl₂ ;

CCl₂ FCClF₂ ;

CClF₂ CClF₂ ;

CHClF₂ ;

CF₃ CHCl₂ ;

CClF₂ CHClF;

CF₃ CHClF;

CCl₂ FCH₃ ;

CClF₂ CH₃ ;

CH₂ F₂ ;

CF₃ CHF₂ ;

;

CHF₂ CHF₂ ;

CF₃ CH₂ F;

CH₂ FCH₂ F;

CF₃ CH₃ ;

CHF₂ CH₃ ;

CO₂ ;

C₃ to C₆ hydrocarbons;

methyl formate; and

mixtures thereof.

7. An improved thermoplastic or thermoset closed-cell polymer composition comprising:

(a) a polymer; and

(b) an effective amount of a gas barrier resin uniformly dispersed in said polymer resin to reduce the permeation of the gas comprising the blowing agent, wherein said gas barrier resin comprises a material selected from the group consisting of;

ethylene/vinyl alcohol copolymers;

polyvinyl alcohol;

polyacrylonitrile and copolymers;

polyvinylidene fluoride;

polyamides;

admixtures of ethylene/vinyl alcohol copolymers and mica; and

mixtures thereof, and;

wherein said gas barrier resin agent is present in the range of from about 0.1 to about 20 weight percent of said foam, said blowing agent having a vapor thermal conductivity which is lower than air, through the foam made using said improved thermoplastic of thermoset polymer composition wherein said blowing agent comprises at least one member from the group consisting of HCFC-22, HCFC-142b, methyl formate, C₃ to C₆ hydrocarbons, HFC-143a, HFC-152, HFC-152a, CO₂, HFC-32, HFC-125, HFC-134, and HFC-134a, wherein said polymer comprises a material selected from the group consisting of;

polyurethanes, polyisocyanurates, and polystyrene.

8. An improved intermediate for a closed-cell polymer foam composition comprising:

(a) a polyol or an isocyanate; and

(b) an effective amount of a gas barrier resin uniformly dispersed in said polyol, or an isocyanate to reduce the permeation of gas through a foam made using said improved intermediate composition, wherein said gas barrier resin comprises a material selected from the group consisting of;

ethylene/vinyl alcohol copolymers;

polyvinyl alcohol;

polyacrylonitrile and copolymers;

polyvinylidene fluoride;

polyamides;

admixtures of ethylene/vinyl alcohol copolymers and mica; and

mixtures thereof, and;

wherein said gas barrier resin agent is present in the range of from about 0.1 to about 20 weight percent of said foam.

9. An improved foaming composition comprising:

(a) at least one blowing agent; and

(b) an effective amount of a gas barrier resin admixed in said blowing agent to reduce the permeation of gas through a closed-cell polymer foam made using said improved foaming composition, wherein said continuous polymeric phase comprises a material selected from the group consisting of polyurethanes, polyisocyanurates, and polystyrene, and;

wherein said gas barrier resin comprises a material selected from the group consisting of;

ethylene/vinyl alcohol copolymers;

polyvinyl alcohol;

polyacrylonitrile and copolymers;

polyvinylidene fluoride;

polyamides;

admixtures of ethylene/vinyl alcohol copolymers and mica; and

mixtures thereof.