Embossed oriented polymer films

• US 6,514,597 B1
• Filed: 02/04/2000
• Issued: 02/04/2003
• Est. Priority Date: 10/01/1997
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Strobel, Joan M., Kapaun, Ronald S., Strobel, Mark A., Hager, Patrick J.
• Primary Examiner(s): Pyon, Harold
• Assistant Examiner(s): Miggins, Michael C.
• Application Number:
  US09/497,971
• Time in Patent Office: 1,096 Days
• Field of Search: 428/174, 428/179, 428/181, 428/183, 428/184, 428/186, 428/213, 428/215, 428/216, 428/220, 428/506, 428/521, 428/523, 428/156, 428/167, 428/332, 428/337, 428/338, 428/339
• US Class Current: 428/167
• CPC Class Codes: B29C 35/0866 using particle radiation
• CPC Class Codes: B29C 59/04 using rollers or endless belts
• CPC Class Codes: B29D 7/01 Films or sheets
• CPC Class Codes: B29K 2995/0039 Amorphous
• CPC Class Codes: B29K 2995/0041 Crystalline
• CPC Class Codes: B29K 2995/005 Oriented
• CPC Class Codes: B29K 2995/0077 Yield strength; Tensile strength
• CPC Class Codes: Y10T 428/24479 including variation in thickness
• CPC Class Codes: Y10T 428/2457 Parallel ribs and/or grooves
• CPC Class Codes: Y10T 428/24628 Nonplanar uniform thickness material
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/24967 Absolute thicknesses specified
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/266 of base or substrate
• CPC Class Codes: Y10T 428/268 Monolayer with structurally defined element
• CPC Class Codes: Y10T 428/269 including synthetic resin or polymer layer or component

Abstract

Embossed oriented thermoplastic films and methods of making them are described. The embossed oriented thermoplastic films have substantially the same mechanical properties as unembossed oriented thermoplastic films. The depth of the embossments ranges from about 1 μm to about 200 μm. The methods include providing an oriented thermoplastic film having first and second major surfaces, softening at least one of the first and second major surfaces to produce a softened surface, embossing the softened surface to produce an embossed oriented thermoplastic film, and cooling the embossed oriented thermoplastic film.

Claims

1. An embossed biaxially oriented thermoplastic film comprising:

a biaxially oriented thermoplastic film having first and second major surfaces;

a plurality of embossments on at least one of the first and second major surfaces, wherein a plurality of the embossments have a depth of at least 1 micrometer and wherein the tensile strength-at-break and tensile elongation-at-break of the embossed biaxially oriented thermoplastic film have a variance of less than 10 percent from the tensile strength-at-break and tensile elongation-at-break of the biaxially oriented thermoplastic film before embossing.

2. The embossed biaxially oriented thermoplastic film of claim 1 wherein the tensile strength-at-break of the embossed biaxially oriented thermoplastic film has a variance of less than 5 percent from the tensile strength-at-break of the biaxially oriented thermoplastic film before embossing.

3. The embossed biaxially oriented thermoplastic film of claim 1 wherein the tensile elongation-at-break of the embossed biaxially oriented thermoplastic film has a variance of less than 5 percent from the tensile elongation-at-break of the biaxially oriented thermoplastic film before embossing.

4. The embossed biaxially oriented thermoplastic film of claim 1 wherein a plurality of the embossments form a plurality of indentations in one major surface and a corresponding plurality of protrusions in the other major surface, said indentations having a depth and said protrusions having a height from about 2 μ

m to about 20 μ

m.

5. The embossed biaxially oriented thermoplastic film of claim 1 selected from polypropylene and polyethylene terephthalate said film having an ASTM Wetting Tension value greater than that of the film before embossing.

6. The embossed biaxially oriented thermoplastic film of claim 1 selected from polypropylene and polyethylene terephthalate said film having an oxygen/carbon atomic ratio on one surface greater than that of such surface before embossing.

7. The embossed biaxially oriented thermoplastic film of claim 1 wherein the biaxially oriented thermoplastic film comprises an amorphous glassy polymer selected from cellulose acetate, poly(p-styrene), syndiotactic polystyrene, poly(vinyl chloride), poly(vinylidene chloride), poly(vinylidene fluoride), poly(vinylidone dichloride), and mixtures thereof.

8. An embossed biaxially oriented semi-crystalline thermoplastic film comprising:

a biaxially oriented semi-crystalline thermoplastic film having first and second major surfaces;

a plurality of embossments on at least one of the first and second major surfaces, wherein a plurality of the embossments have a depth of at least 1 micrometer and wherein the tensile strength-at-break and tensile elongation-at-break of the embossed biaxially oriented semi-crystalline thermoplastic film have a variance of less than 10 percent from the tensile strength-at-break and tensile elongation-at-break of the biaxially oriented semi-crystalline thermoplastic film before embossing.

9. The embossed biaxially oriented semi-crystalline thermoplastic film of claim 8 wherein the tensile strength-at-break of the embossed biaxially oriented thermoplastic film has a variance of less than 5 percent from the tensile strength-at-break of the biaxially oriented thermoplastic film.

10. The embossed biaxially oriented semi-crystalline thermoplastic film of claim 8 wherein the tensile elongation-at-break of the embossed biaxially oriented thermoplastic film has a variance of less than 5 percent from the tensile elongation-at-break of the biaxially oriented thermoplastic film.

11. The embossed biaxially oriented semi-crystalline thermoplastic film of claim 8 wherein a plurality of the embossments have a depth from about 2 μ

m to about 20 μ

m.

12. The embossed biaxially oriented semi-crystalline thermoplastic film of claim 8 wherein the biaxially oriented semi-crystalline thermoplastic film comprises a polymer selected from polyethylene, polypropylene, poly(ethylene/propylene), poly(ethylene/1-butylene), poly(propylene/1-butylene), poly(ethylene/propylene/1-butylene), poly(polyethylene terephthalate), poly(polyethylene butyrate), poly(polyethylene napthalate), and mixtures thereof.

13. The embossed biaxially oriented semi-crystalline thermoplastic film of claim 8 wherein the biaxially oriented semi-crystalline thermoplastic film comprises a polymer selected from linear-low-density polyethylene, high-density polyethylene, ultra-high-molecular-weight polyethylene, isotactic polypropylene, blends of isotactic polypropylene and substantially syndiotactic polypropylene and blends of isotactic polypropylene and polyethylene.

14. A layered film construction comprising at least two layers at least one of which is a biaxially oriented thermoplastic film layer having first and second major surfaces having a plurality of embossments on at least one of the first and second major surfaces wherein a plurality of the embossments have a depth of at least 1 micrometer, and another layer selected from the group of thermoplastic polymer films, porous films, metal foils, woven materials, non-woven materials, and combinations thereof;

wherein the tensile strength-at-break and tensile elongation-at-break of the layered film have a variance of less than 10 percent from the tensile strength-at-break and tensile elongation-at-break of the same film without embossing.

15. The layered film construction of claim 14 further comprising an adhesive layer on at least a portion of at least one major surface of the film.

16. The layered film construction of claim 14 wherein the tensile strength-at-break of the layered film has a variance of less than 5 percent from the tensile strength-at-break of the same film without embossing.

17. The layered film construction of claim 14 wherein the tensile elongation-at-break of the layered film has a variance of less than 5 percent from the tensile elongation-at-break of the same film without embossing.

18. The layered film construction of claim 14 wherein the biaxially oriented thermoplastic film layer comprises an amorphous glassy polymer selected from cellulose acetate, poly(p-styrene), syndiotactic polystyrene,-poly(vinyl chloride), poly(vinylidene chloride), poly(vinylidene fluoride), poly(vinylidone dichloride), and mixtures thereof.

19. The layered film construction of claim 14 wherein a plurality of the embossments have a depth from about 2 μ

m to about 20 μ

m.

20. The layered film construction of claim 14 wherein the biaxially oriented thermoplastic film layer comprises a semi-crystalline polymer.

21. The layered film construction of claim 20 wherein the biaxially oriented thermoplastic film layer comprises a polymer selected from polyethylene, polypropylene, poly(ethylene/propylene), poly(ethylene/1-butylene), poly(propylene/1-butylene), poly(ethylene/propylene/l-butylene), poly(polyethylene terephthalate), poly(polyethylene butyrate), poly(polyethylene napthalate), and mixtures thereof.

22. The layered film construction of claim 20 wherein the biaxially oriented thermoplastic film layer comprises a polymer selected from linear-low-density polyethylene, high-density polyethylene, ultra-high-molecular-weight polyethylene, isotactic polypropylene, blends of isotactic polypropylene and substantially syndiotactic polypropylene and blends of isotactic polypropylene and polyethylene.