Conductive multilayer sheet for thermal forming applications

• US 10,227,465 B2
• Filed: 04/20/2015
• Issued: 03/12/2019
• Est. Priority Date: 08/07/2014
• Status: Active Grant

• Current Assignee: SHPP Global Technologies BV
• Original Assignee: SABIC Global Technologies BV (Government of Saudi Arabia)
• Inventors: Feng, Wei, Xu, Yuzhen, Lai, Hengjie, Chen, Zhe, Xu, Yonglei
• Primary Examiner(s): Boykin, Terressa
• Application Number:
  US15/502,312
• Publication Number:
  US 20170226303A1
• Time in Patent Office: 1,422 Days
• Field of Search: 428411, 428412
• CPC Class Codes: B29B 11/12 Compression moulding
• CPC Class Codes: B29B 13/08 by using wave energy or particle radiation
• CPC Class Codes: B29C 51/002 characterised by the choice of material
• CPC Class Codes: B29C 51/02 Combined thermoforming and manufacture of the preform
• CPC Class Codes: B29C 51/10 Forming by pressure difference, e.g. vacuum
• CPC Class Codes: B29K 2069/00 Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2105/256 Sheets, plates, blanks or films
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 27/365 comprising polycarbonates
• CPC Class Codes: C08J 2367/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds; C08J2367/06 takes precedence
• CPC Class Codes: C08J 2369/00 Characterised by the use of polycarbonates; Derivatives of polycarbonates
• CPC Class Codes: C08J 2433/00 Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
• CPC Class Codes: C08J 2433/08 Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C08J 2435/02 Characterised by the use of homopolymers or copolymers of esters C08J2435/06, C08J2435/08 take precedence
• CPC Class Codes: C08J 2475/14 Polyurethanes having carbon-to-carbon unsaturated bonds
• CPC Class Codes: C08J 7/0423 with at least one layer of inorganic material and at least one layer of a composition containing a polymer binder
• CPC Class Codes: C08J 7/043 Improving the adhesiveness of the coatings per se, e.g. forming primers adhesives in the form of films or foils characterised by the primer layers between the polymer carriers and the adhesives C09J7/50
• CPC Class Codes: C08J 7/044 Forming conductive coatings; Forming coatings having anti-static properties
• CPC Class Codes: C08J 7/046 Forming abrasion-resistant coatings; Forming surface-hardening coatings
• CPC Class Codes: C08J 7/16 : with polymerisable compounds
• CPC Class Codes: C08J 7/18 : using wave energy or particle radiation

Abstract

A method of making a multilayer sheet includes: forming a substrate including a substrate first surface and a substrate second surface; applying a conductive layer including a base and a conductive coating to the substrate first surface; and applying an ultraviolet cured coating layer to a surface of the conductive layer opposite that in contact with the substrate second surface, wherein the ultraviolet cured coating layer comprises a multifunctional acrylate oligomer and an acrylate monomer; pressing the substrate, conductive layer, and ultraviolet cured coating layer together to form a stack; heating the stack; activating the ultraviolet cured coating layer with an ultraviolet radiation source; and removing the base from the stack leaving a conductive multilayer sheet; wherein the ultraviolet cured coating layer remains adhered to the conductive layer.

Claims

1. A multilayer sheet, comprising:

a substrate comprising a substrate first surface and a substrate second surface;

a conductive layer having a conductive layer first surface disposed on the substrate first surface; and

an ultraviolet curable coating layer, comprising

a multifunctional acrylate oligomer; and

an acrylate monomer;

wherein the ultraviolet curable coating layer includes a total weight, wherein 30% to 80% of the total weight comprises the multifunctional acrylate oligomer, and wherein 15% to 65% of the total weight comprises the acrylate monomer;

wherein the ultraviolet curable coating layer is disposed on a conductive layer second surface.

2. The multilayer sheet of claim 1, wherein the multifunctional acrylate oligomer comprises an aliphatic urethane acrylate oligomer, a pentaerythritol tetraacrylate, an aliphatic urethane acrylate, an acrylic ester, a dipentaerythritol dexaacrylate, an acrylated resin, a trimethylolpropane triacrylate (TMPTA), a dipentaerythritol pentaacrylate ester, or a combination comprising at least one of the foregoing.

3. The multilayer sheet of claim 1, wherein the multifunctional acrylate oligomer comprises an aliphatic urethane acrylate oligomer and a pentaerythritol tetraacrylate, wherein the multifunctional acrylate oligomer includes a multifunctional acrylate oligomer weight, wherein 30% to 50% of the multifunctional acrylate oligomer weight comprises the aliphatic urethane acrylate oligomer, and wherein 50% to 70% of the multifunctional acrylate oligomer weight comprises the pentaerythritol tetraacrylate.

4. The multilayer sheet of claim 1, wherein the ultraviolet curable coating layer further comprises a photoinitiator, wherein 3% to 7% of the total weight comprises the photoinitiator.

5. The multilayer sheet of claim 4, wherein the photoinitiator comprises an α

-hydroxyketone photoinitiator.

6. The multilayer sheet of claim 5, wherein the α

-hydroxyketone photoinitiator is 1-hydroxy-cyclohexylphenylketone.

7. The multilayer sheet of claim 1, wherein the acrylate monomer comprises 1,6-hexanediol diacrylate.

8. The multilayer sheet of claim 1, wherein the substrate comprises polycarbonate, poly(methyl methacrylate) (PMMA), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), a cyclic olefin copolymer (COC), polyetherimide (PEI), polystyrene, polyimide, polypropylene (PP), polyethylene (PE), polyvinyl fluouride (PVF), polyvinylidene fluoride (PVDF), glass, or a combination comprising at least one of the foregoing.

9. The multilayer sheet of claim 1, wherein the ultraviolet curable coating layer can adhere to a polycarbonate substrate with an adhesion strength of 5B as measured according to ASTM D3359.

10. The multilayer sheet of claim 1, wherein the multilayer sheet has a transmittance of greater than or equal to 80% as measured according to ASTM D1003 Procedure A using CIE standard illuminant C.

19. The multilayer sheet of claim 1, wherein the conductive layer comprises metal particles arranged in a network of interconnected metal traces defining randomly shaped openings on the substrate first surface.

11. A method of making a multilayer sheet, comprising:

forming a substrate comprising a substrate first surface and a substrate second surface;

applying a conductive layer comprising a base and a conductive coating to the substrate first surface; and

applying an ultraviolet cured coating layer to a surface of the conductive layer opposite that in contact with the substrate second surface, wherein the ultraviolet cured coating layer comprises a multifunctional acrylate oligomer and an acrylate monomer, wherein the ultraviolet cured coating layer includes a total weight, wherein 30% to 80% of the total weight comprises the multifunctional acrylate oligomer, and wherein 15% to 65% of the total weight comprises the acrylate monomer;

pressing the substrate, conductive layer, and ultraviolet cured coating layer together to form a stack;

heating the stack;

activating the ultraviolet cured coating layer with an ultraviolet radiation source; and

removing the base from the stack leaving a conductive multilayer sheet;

wherein the ultraviolet cured coating layer remains adhered to the conductive layer.

12. The multilayer sheet of claim 11, wherein the ultraviolet curable coating layer further comprises a photoinitiator, wherein 3% to 7% of the total weight comprises the photoinitiator.

13. The method of claim 11, further comprising thermoforming the multilayer sheet to form a thermoformed article.

14. The method of claim 13, wherein the thermoforming comprises:

placing the multilayer sheet on a clamp of a mold;

fixing the multilayer sheet to the clamp;

pushing the multilayer sheet out of the clamp by raising the mold;

lowering the mold;

heating the multilayer sheet while simultaneously beginning the vacuum and raising the mold to form the thermoformed article.

15. The method of claim 11, wherein the ultraviolet curable coating layer can adhere to a polycarbonate substrate with an adhesion strength of 5B as measured according to ASTM D3359.

16. The method of claim 11, wherein the thermoformed article has a transmittance of greater than or equal to 80% as measured according to ASTM D1003 Procedure A using CIE standard illuminant C.

17. The method of claim 11, wherein the surface resistivity of the thermoformed article is less than or equal to 60 Ohms.

18. The method of claim 11, wherein the thermoformed article has an elongation of less than or equal to 20% at a temperature of less than or equal to 130°

C., when measured by dynamic mechanical analysis.

20. The method of claim 11, wherein the conductive layer comprises metal particles arranged in a network of interconnected metal traces defining randomly shaped openings on the substrate first surface.