# US 5,350,476 A · Extrusion coating process for producing a high gloss polyethylene coating

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- Number: US 5,350,476 A
- Document ID: US5350476A
- Status: Granted
- Kind: A
- Application number: 08/151,314
- Filed: 1993-11-12
- Granted: 1994-09-27
- Earliest claimed: 1992-02-28
- Assignees: Eastman Chemical Company
- Inventors: Ray Edwards
- Web page: https://patentgrep.com/patent/US5350476A

## CPC

- C09D 123/06: Polyethylene
- B05D 1/265: {Extrusion coatings}
- B05D 3/0446: {of a polymeric substrate}
- B05D 3/08: by flames
- B05D 3/101: {Pretreatment of polymeric substrate}
- Y10T 428/31: Surface property or characteristic of web, sheet or block
- Y10T 428/31504: Composite [nonstructural laminate]
- Y10T 428/31855: Of addition polymer from unsaturated monomers
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A process of producing a high gloss oxidizable extrusion coated polyethylene is provided. This process entails extrusion coating a low density polyethylene of narrow molecular weight distribution having a low melt index, a low swell ratio, and a polydispersity index below 9.

## Claims

### Claim 1

An extrusion coating process comprising; extrusion coating onto a substrate against a glossy chill roll, a low density polyethylene of narrow molecular weight distribution having a melt index of 2 to 4-dg/min at 190.degree. C., a swell ratio of 1.2 to 1.3, an annealed density of 0.92 to 0.93-g/cc, and a polydispersity index of 6 to 9.

### Claim 2 (depends on 1)

The extrusion coating process according to claim 1 wherein the low density polyethylene has a melt index of 2.2 to 3-dg/min, a swell ratio of 1.25 to 1.27, an annealed density of 0.922 to 0.927-g/cc, and a polydispersity index of 6.0 to 7.8.

### Claim 3 (depends on 2)

The process according to claim 2 wherein the low density polyethylene has a melt index of 2.5-dg/min, a swell ratio of 1.26, an annealed density of 0.926-g/cc, and a polydispersity index of about 7.

### Claim 4 (depends on 1)

The process according to claim 1 wherein the glossy chill roll has a root mean square surface finish less than 10.

### Claim 5 (depends on 4)

The process according to claim 4 wherein the glossy chill roll has a root mean square surface finish of at least 1, but no more than 6.

### Claim 6 (depends on 5)

The process according to claim 5 wherein the glossy chill roll has a root mean square surface finish of no more than 2.

### Claim 7 (depends on 1)

The process according to claim 1 wherein the glossy chill roll surface temperature is less than 20.degree. C., but higher than the environmental dew point of water.

### Claim 8 (depends on 1)

The process according to claim 1 wherein the low density polyethylene is extruded at a temperature greater than 300.degree. C.

### Claim 9 (depends on 1)

The process according to claim 1 further comprising oxidizing the resultant coated substrate under conditions sufficient to impart surface oxidation.

### Claim 10 (depends on 9)

The process according to claim 9 wherein the oxidation is conducted by direct flame impingement, corona discharge, or ozone exposure.

### Claim 11 (depends on 1)

The process according to claim 1 wherein the low density polyethylene is a low density polyethylene homopolymer.