Process for producing polyvinyl alcohol articles

• US 9,797,073 B1
• Filed: 06/26/2012
• Issued: 10/24/2017
• Est. Priority Date: 07/18/2011
• Status: Active Grant

• Current Assignee: Lakeland Industries Incorporated
• Original Assignee: Lakeland Industries Incorporated
• Inventors: Smith, Novis, Roberson, Charles
• Primary Examiner(s): Salvatore, Lynda
• Application Number:
  US13/533,392
• Time in Patent Office: 1,946 Days
• Field of Search: 442101, 428323
• CPC Class Codes: B29C 35/049 using steam or damp
• CPC Class Codes: B29C 59/00 Surface shaping of articles, e.g. embossing; Apparatus therefor in-mould printing B29C37/0025; by using liquids B29C71/0009; by using gases without chemical reaction B29C71/009; for decorating in general B44; abrasive blasting B24C; chemical aspects C08J7/00
• CPC Class Codes: B29C 59/04 using rollers or endless belts
• CPC Class Codes: B29C 71/0009 using liquids, e.g. solvents, swelling agents spectacle cases, e.g. for cleaning contact lenses A45C11/04; disinfecting or sterilising contact lenses A61L12/00, using liquid substances A61L2/20; cleaning involving the use of liquid in general B08B3/00; for hydrating contact lenses B29D11/00067
• 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 2307/73 Hydrophobic
• CPC Class Codes: B32B 2437/00 Clothing anti-ballistic clothing B32B2571/02
• CPC Class Codes: B32B 2571/00 Protective equipment
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/306 comprising vinyl acetate or vinyl alcohol (co)polymers
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: D04H 13/00 Other non-woven fabrics
• CPC Class Codes: D06B 1/00 Applying liquids, gases or vapours onto textile materials to effect treatment, e.g. washing, dyeing, bleaching, sizing or impregnating mercerising D06B7/00; solvent-treatment D06B9/00; treatment of selected parts of textile materials D06B11/00; with aid of vibration D06B13/00
• CPC Class Codes: D06C 7/00 Heating or cooling textile fabrics
• CPC Class Codes: D06M 11/05 with water, e.g. steam; with heavy water
• CPC Class Codes: D06M 11/84 combined with mechanical treatment combined with mechanical tension, e.g. mercerising D06M11/40
• CPC Class Codes: D06M 15/00 Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment D06M10/00, D06M14/00 take precedence; treatment with inorganic polyphosphates D06M11/72
• CPC Class Codes: D06M 16/00 Biochemical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. enzymatic
• CPC Class Codes: D06M 2101/24 Polymers or copolymers of alkenylalcohols or esters thereof; Polymers or copolymers of alkenylethers, acetals or ketones
• CPC Class Codes: D06N 3/00 : Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
• CPC Class Codes: D06N 3/0011 : using non-woven fabrics
• CPC Class Codes: Y10T 442/2213 : Coating or impregnation is specified as weather proof, water vapor resistant, or moisture resistant
• CPC Class Codes: Y10T 442/2221 : Coating or impregnation is specified as water proof
• CPC Class Codes: Y10T 442/656 : Preformed metallic film or foil or sheet [film or foil or sheet had structural integrity prior to association with the nonwoven fabric]
• CPC Class Codes: Y10T 442/679 : Natural or synthetic rubber sheet or film

Abstract

The present invention provides a process for modifying the surface of a polyvinyl alcohol film or fabric by applying heat and pressure to the film or fabric to increase the moisture on the surface which is held by the fabric and to coalesce the surface fibers and reduce the porosity of the surface.

Claims

1. A process for producing a polyvinyl alcohol fabric having at least one surface that is coalesced and has a reduced porosity which comprises the step of applying heat and pressure to a polyvinyl alcohol fabric having a moisture content of at least 5-10% by weight so as to increase the moisture at the surface and cause surface fibers on a surface of the fabric to coalesce and to lower its surface porosity to a desired level, wherein the initial fabric is passed through a pair of calendar rolls, wherein one of the rolls is a heated roller and an opposed one of the rolls is an unheated roller having a surface coating of a high melting polymer film.

2. The process of claim 1 wherein both surfaces of the fiber have been treated to form a coalesced and reduced porosity surface.

3. The process of claim 1 wherein the unheated calendar roll is relatively softer than the heated calendar roll.

4. The process of claim 1 wherein the polymer film is selected from the group consisting of polyamide, polytetrafluoroethylene, polyurethane and silicone rubber.

5. The process of claim 1 wherein the fabric is treated with an additive on the surface to be coalesced.

6. The process of claim 5 where the additive is selected from the group consisting of an anti-static agent, water repellant, and a dye.

7. The process of claim 1 wherein the moisture content of the initial fabric is between 5 to 15% by weight.

8. The process of claim 1 wherein the fabric is a laminate of another thermoplastic.

9. The process of claim 8 wherein the other thermoplastic comprises a polyolefin.

10. The process of claim 9 wherein said polyolefin is polyethylene.

11. A polyvinyl alcohol fabric having at least one coalesced surface with a reduced porosity prepared by the process of claim 1.

12. The polyvinyl alcohol fabric of claim 11 which comprises a water repellant coating on the coalesced surface.

13. The process of claim 1 wherein the polyvinyl alcohol in the fabric has 98 percent or greater hydrolyzed acetyl groups.

14. The process of claim 1 wherein the heated roll is heated to a temperature of between about 120 to 190°

C., and wherein the pair of opposed rolls apply the heat and pressure to the polyvinyl alcohol fabric.

15. The process of claim 14 wherein the unheated roll has a relatively softer surface than the heated roll.

16. The process of claim 1 further comprising after applying heat and pressure, passing the fabric through a further pair of opposed rolls, wherein one or both of the rolls are cooled.

17. The process of claim 16 wherein one or both of the further pair of opposed rolls are chilled at a temperature below room temperature.

18. The process of claim 16 wherein before the passing the fabric through the further pair of opposed rolls, spraying an additive onto the surface of the fabric.

19. A process for producing a polyvinyl alcohol fabric having at least one surface that is coalesced and has a reduced porosity which comprises the step of applying heat and pressure to a polyvinyl alcohol fabric by a pair of opposed calendar rollers wherein one of the rollers is a heated metal roller and the other one of the rollers is unheated and includes a surface coating of a high melting polymer film and is relatively softer that the heated metal roller, wherein the polyvinyl fabric has a moisture content of 5 to 15% by weight so as to increase the moisture at the surface and cause surface fibers on a surface of the fabric to coalesce and to lower its surface porosity to a desired level, further comprising after applying heat and pressure, passing the fabric through a further pair of opposed rolls, wherein one or both of the further pair of opposed rolls are cooled.

20. A process for producing a polyvinyl alcohol fabric having at least one surface that is coalesced and has a reduced porosity which comprises the step of applying heat and pressure to a polyvinyl alcohol fabric having a moisture content of at least 5-10% by weight so as to increase the moisture at the surface and cause surface fibers on a surface of the fabric to coalesce and to lower its surface porosity to a desired level, wherein the initial fabric is passed through a pair of calendar rolls, wherein one of the rolls is a heated roller and an opposed one of the rolls is an unheated roller, and wherein the unheated calendar roll is relatively softer than the heated calendar roll.