Manufacturing process for coated polyester film

• US 9,522,983 B2
• Filed: 05/15/2014
• Issued: 12/20/2016
• Est. Priority Date: 02/09/2006
• Status: Active Grant

• Current Assignee: DuPont Performance Elastomers L (Bristol-Myers Squibb Company)
• Original Assignee: DuPont Performance Elastomers L (Bristol-Myers Squibb Company)
• Inventors: Eveson, Robert William, Hodgson, Andrew Nathan, MacKerron, Duncan Henry, Hashimoto, Katsuyuki
• Primary Examiner(s): Webb, Gregory
• Application Number:
  US14/278,191
• Publication Number:
  US 20140295174A1
• Time in Patent Office: 950 Days
• US Class Current: 1/1
• CPC Class Codes: B29C 2071/022 Annealing
• CPC Class Codes: B29C 71/02 Thermal after-treatment B29C71/0063 and B29C71/0072 take precedence
• CPC Class Codes: B29K 2067/00 Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2995/0048 Without internal tensions
• CPC Class Codes: C08J 2367/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds; C08J2367/06 takes precedence
• 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 7/0427 with only one layer of a composition containing a polymer binder with more layers C08J7/042
• 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 7/046 Forming abrasion-resistant coatings; Forming surface-hardening coatings
• CPC Class Codes: Y10S 428/91 Product with molecular orientation
• CPC Class Codes: Y10T 428/263 Coating layer not in excess of 5 mils thick or equivalent
• CPC Class Codes: Y10T 428/264 Up to 3 mils
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/266 of base or substrate
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane
• CPC Class Codes: Y10T 428/31736 Next to polyester
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31797 Next to addition polymer from unsaturated monomers

Abstract

A biaxially oriented composite film includes a polyester substrate supporting one or more coatings on one or both surfaces of said substrate,

• • wherein the polyester substrate is a biaxially oriented film;
  • wherein the one or more coatings is/are derived from a predominantly inorganic hardcoat coating composition including inorganic particles contained in a polymerisable predominantly inorganic matrix; and wherein the biaxially oriented composite film has been annealed at a temperature T_a (° C.) above Tg where Tg<T_a≦Tg+100 (° C.) for a time t after thermal equilibrium where 1 hour ≦t≦72 hours. A method of making the film is provided.

Claims

1. A method of producing a biaxially oriented composite film comprising a polyester substrate supporting one or more coatings on one or both surfaces of said substrate, wherein said polyester substrate is a biaxially oriented film, said method comprising the steps of:

disposing on one or both surfaces of said polyester substrate said coating wherein said coating is derived from a predominantly inorganic hardcoat coating composition comprising inorganic particles contained in a polymerisable predominantly inorganic matrix; and

subsequently annealing said biaxially oriented composite film at a temperature T_a (°

C.) above Tg where Tg<

T_a≦

Tg+100 (°

C.) for a time t after thermal equilibrium where 1 hour ≦

t≦

72 hours.

2. The method according to claim 1, wherein 1 hour≦

t≦

48 hours.

3. The method according to claim 1, wherein 1 hour≦

t≦

24 hours.

4. The method according to claim 1, wherein after said annealing, the annealed composite film is cooled.

5. The method according to claim 1, wherein said coating is derived from a predominantly inorganic hardcoat coating composition comprising inorganic particles contained in a polymerisable predominantly inorganic matrix selected from polysiloxanes.

6. The method according to claim 1, wherein the coating is derived from a composition comprising:

(a) from about 5 to about 50 weight percent solids, the solids comprising from about 10 to about 70 weight percent silica and from about 90 to about 30 weight percent of a partially polymerized organic silanol of the general formula RSi(OH)₃, wherein R is selected from methyl and up to about 40% of a group selected from the group consisting of vinyl, phenyl, gamma-glycidoxypropyl, and gamma-methacryloxypropyl, and

(b) from about 95 to about 50 weight percent solvent, the solvent comprising from about 10 to about 90 weight percent water and from about 90 to about 10 weight percent lower aliphatic alcohol, wherein the coating composition has a pH of from about 3.0 to about 8.0.

7. The method according to claim 1, wherein a coating has a dry thickness of from 1 to 20 microns.

8. The method according to claim 1, wherein the annealed and coated film exhibits a haze value of less than 10%.

9. The method according to claim 1, wherein the coated and annealed film exhibits a haze value which is no more than a 10% increase on the haze value of the coated film before annealing.

10. The method according to claim 1, wherein said polyester is poly(ethylene terephthalate).

11. The method according to claim 1, wherein said polyester is poly(ethylene naphthalate).

12. The method according to claim 11, wherein said polyester is derived from 2,6-naphthalenedicarboxylic acid.

13. The method according to claim 11, wherein the poly(ethylene naphthalate) has an intrinsic viscosity of 0.5-1.5.

14. The method according to claim 1, wherein said biaxially oriented polyester film is a heat-stabilised, heat-set, biaxially oriented film.

15. The method according to claim 14, wherein said heat-stabilised, heat-set, biaxially oriented film exhibits one or more of:

(i) a shrinkage at 30 mins at 230°

C. of less than 1%;

(ii) a residual dimensional change Δ

L_r measured at 25°

C. before and after heating the film from 8°

C. to 200°

C. and then cooling to 8°

C., of less than 0.75%; and

/or

(iii) a coefficient of linear thermal expansion (CLTE) within the temperature range from −

40°

C. to +100°

C. of less than 40×

10<sup>−

6</sup>/°

C.

16. The method according to claim 1, wherein said biaxially oriented polyester film has a thickness in a range from 25 μ

m to 250 μ

m.

17. A biaxially oriented composite film comprising a polyester substrate supporting one or more coatings on one or both surfaces of said substrate,

wherein said polyester substrate is a biaxially oriented film;

wherein said one or more coatings is/are derived from a predominantly inorganic hardcoat coating composition comprising inorganic particles contained in a polymerisable predominantly inorganic matrix; and

wherein the biaxially oriented composite film has been annealed at a temperature T_a (°

C.) above Tg where Tg<

T_a≦

Tg+100(°

C.) for a time t after thermal equilibrium where 1 hour ≦

t≦

72 hours.

18. The film according to claim 17, wherein 1 hour ≦

t≦

48 hours.

19. The film according to claim 17, wherein 1 hour ≦

t≦

24 hours.

20. The film according to claim 17, wherein said coating is derived from a predominantly inorganic hardcoat coating composition comprising inorganic particles contained in a polymerisable predominantly inorganic matrix selected from polysiloxanes.

21. The film according to claim 17, wherein the coating is derived from a composition comprising:

(a) from about 5 to about 50 weight percent solids, the solids comprising from about 10 to about 70 weight percent silica and from about 90 to about 30 weight percent of a partially polymerized organic silanol of the general formula RSi(OH)₃, wherein R is selected from methyl and up to about 40% of a group selected from the group consisting of vinyl, phenyl, gamma-glycidoxypropyl, and gamma-methacryloxypropyl, and

(b) from about 95 to about 50 weight percent solvent, the solvent comprising from about 10 to about 90 weight percent water and from about 90 to about 10 weight percent lower aliphatic alcohol, wherein the coating composition has a pH of from about 3.0 to about 8.0.

22. The film according to claim 17, wherein said at least one coating has a dry thickness of from 1 to 20 microns.

23. The film according to claim 17, wherein the annealed composite film exhibits a haze value of less than 10%.

24. The film according to claim 17, wherein the annealed composite film exhibits a haze value which is no more than a 10% increase on the initial haze value of the coated film before annealing.

25. The film according to claim 17, wherein said polyester is poly(ethylene terephthalate).

26. The film according to claim 17, wherein said polyester is poly(ethylene naphthalate).

27. The film according to claim 26, wherein said polyester is derived from 2,6-naphthalenedicarboxylic acid.

28. The film according to claim 26, wherein the poly(ethylene naphthalate) has an intrinsic viscosity of 0.5-1.5.

29. The film according to claim 17, wherein said polyester substrate is a heat-stabilised, heat-set, biaxially oriented film.

30. The film according to claim 17, wherein said polyester substrate exhibits one or more of:

(i) a shrinkage at 30 mins at 230°

C. of less than 1%;

(ii) a residual dimensional change Δ

L_r measured at 25°

C. before and after heating the biaxially oriented film from 8°

C. to 200°

C. and then cooling to 8°

C., of less than 0.75%; and

/or

(iii) a coefficient of linear thermal expansion (CLTE) within the temperature range from −

40°

C. to +100°

C. of less than 40×

10<sup>−

6</sup>/°

C.

31. The film according to claim 17, wherein said polyester substrate has a thickness in a range from 25 μ

m to 250 μ

m.