Foam gasket and bonding tape based on polyurethane dispersions

Patent metadata

Field	Value
Publication number	US-9751241-B2
Application number	US-201414300813-A
Country	US
Kind code	B2
Filing date	Jun 10, 2014
Priority date	Jun 13, 2013
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A polymer sheet includes a polyurethane core. The polyurethane core has a first major surface and a second major surface opposite the first major surface. The polymer sheet can have at least one functional layer overlying a major surface. The polymer sheet has a thickness t PS . The polyurethane core has a thickness t PC . In embodiments t PC can be at least 0.3 t PS . The polyurethane core can have at least one of the following property:
(i) a Scratch Resistance Rating, as further described herein, of not greater than about 10 wt %, (ii) an elongation at break of at least 200%, (iii) a tensile strength at break of at least 0.3 MPa, (iv) a loss of tensile strength of not greater than about 30% when exposed to UV light according to standard SAE J1960 (Rev. August 2003).

The polymer sheet can be used for gaskets or bonding tapes.

First claim

The invention claimed is:

1. A polymer sheet comprising:
a polyurethane core, having a first major surface and a second major surface opposite the first major surface; and
at least one functional layer;
wherein the polymer sheet has a thickness tPS and the polyurethane core has a thickness tPC,
wherein tPC is at least 0.3 tPS,
wherein the polyurethane core comprises polyurethane polymer, and
wherein the polyurethane core has a loss of tensile strength when exposed to UV light according to standard SAE J1960 (Rev. August 2003) of not greater than 30%.

2. The polymer sheet according to claim 1 , wherein the polymer sheet has a primary aspect ratio of at least 400.

3. The polymer sheet according to claim 1 , wherein the functional layer is selected from the group consisting of a permanent liner, a release liner, a topcoat, and an adhesive.

4. The polymer sheet according to claim 1 , wherein the functional layer comprises a permanent liner, and the permanent liner comprises a thermoplastic selected from the group consisting of polyethylene, polyester, and polyimide.

5. The polymer sheet according to claim 1 , wherein the functional layer comprises a permanent liner, and the permanent liner comprises ultra-high molecular weight polyethylene.

6. The polymer sheet according to claim 1 , wherein the functional layer is selected from the group consisting of a permanent liner, a release liner, and an adhesive layer, and wherein the functional layer has a thickness of in a range of from 0.01 mm to 0.1 mm.

7. The polymer sheet according to claim 1 , wherein the functional layer is a release liner, and wherein the release liner includes a-polyester, polyethylene, polypropylene, or paper.

8. The polymer sheet according to claim 1 , wherein the functional layer is a topcoat, and wherein the topcoat has a thickness in a range of from 0.001 mm to 0.01 mm.

9. The polymer sheet according to claim 1 , wherein the functional layer is a pressure sensitive adhesive selected from the group consisting of an acrylic adhesive, a silicon adhesive, a rubber hot melt adhesive, an acrylic copolymer, and a rubber acrylic copolymer.

10. The polymer sheet according to claim 1 , wherein the polymer sheet is in a form of a roll.

11. The polymer sheet according to claim 1 , wherein the polyurethane core has a thickness in a range of from 0.2 mm to 3.0 mm.

12. The polymer sheet according to claim 1 , wherein the loss of tensile strength when exposed to UV light according to standard SAE J1960 (Rev. August 2003) is not greater than 25%.

13. The polymer sheet according to claim 1 , wherein the polyurethane core has a compression force deflection at 25% compression of at least 3 kPa.

14. The polymer sheet according to claim 1 , wherein the polyurethane core when exposed to UV light according to standard SAE J1960 (Rev. August 2003) has a discoloration ΔE of not greater than 4.0.

15. The polymer sheet according to claim 1 , wherein the polyurethane core when exposed to UV light according to standard SAE J1960 (Rev. August 2003) has a yellowing Δb of not greater than 2.

16. The polymer sheet according to claim 1 , wherein the polyurethane core is free of pigment.

17. A method of preparing a polymer sheet, the method comprising:
frothing a polyurethane dispersion into a froth;
casting the froth onto a liner;
treating the froth to have a uniform thickness;
drying the froth to form a polyurethane core having a thickness of at least 0.5 of a total thickness of the polymer sheet,
wherein the polyurethane core comprises polyurethane polymer, wherein the polyurethane core has a loss of tensile strength when exposed to UV light according to standard SAE J1960 (Rev. August 2003) of not greater than about 30%.

18. The method according to claim 17 further comprising casting a topcoat layer onto the polymer sheet, wherein the topcoat layer comprises a polyurethane coating, and wherein the topcoat has a thickness in a range of from 0.001 mm to 0.01 mm.

19. An assembly comprising:
a first member;
a second member; and
a gasket;
wherein the gasket includes a polyurethane core,
wherein the polyurethane core has a first major surface and a second major surface opposite the first major surface,
wherein the gasket is compressed between the first member and the second member at a compression of at least about 10%,
wherein the polyurethane core comprises a polyurethane polymer, and
wherein the polyurethane core has a loss of tensile strength when exposed to UV light according to standard SAE J1960 (Rev. August 2003) of not greater than 30%.

20. The assembly according to claim 19 , wherein the assembly is an electronic device and wherein the first member and the second member are components of the electronic device.

Assignees

• Saint Gobain Performance Plastics Corp

Inventors

• Guan Jing
• Dong Yue
• Moineau Georges

Classifications

• B29L2009/005

  coated · CPC title

• Y10T428/1457

  Silicon · CPC title

• B29C39/203 Primary

  Making multilayered articles · CPC title

• B29K2995/0087

  Wear resistance · CPC title

• B29L2031/265

  Packings, Gaskets · CPC title