# US 4,399,173 A · Multilayer films comprising low pressure, low density polyethylene

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- Number: US 4,399,173 A
- Document ID: US4399173A
- Status: Granted
- Kind: A
- Application number: 06/336,592
- Filed: 1982-01-04
- Granted: 1983-08-16
- Earliest claimed: 1982-01-04
- Assignees: Union Carbide Corporation
- Inventors: John Anthony; Stuart J. Kurtz
- Web page: https://patentgrep.com/patent/US4399173A

## CPC

- B32B 27/32: comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)}
- B32B 2323/046: LDPE, i.e. low density polyethylene
- Y10T 428/1334: Nonself-supporting tubular film or bag [e.g., pouch, envelope, packet, etc.]
- Y10T 428/31913: Monoolefin polymer
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A multilayer plastic film free of melt fracture suitable for use in packaging and making bags wherein the film comprises a core layer of low melt index, low pressure, low density polyethylene, and two outer layers of a high melt index, low pressure, low density polyethylene. The process of making the multilayer film is also disclosed.

## Claims

### Claim 1

A multilayer film free of melt fracture comprising a core layer of low melt index, low pressure, low density polyethylene between two outer layers of a high melt index, low pressure, low density polyethylene said low melt index polyethylene having a melt index of between about 0.2 decigrams per minute and about 3.0 decigrams per minute, and said high melt index polyethylene having a melt index of greater than about 3.0 decigrams per minute.

### Claim 2 (depends on 1)

A multilayer film as in claim 1 wherein said core layer of said polyethylene has a melt index of between about 0.2 and about 2.0 decigrams per minute.

### Claim 3 (depends on 1)

A multilayer film as in claim 1 wherein said outer layers of said polyethylene have a melt index of between about 5.0 decigrams per minute and about 20.0 decigrams per minute.

### Claim 4 (depends on 1)

A multilayer film as in claim 1 wherein the thickness of said film is between about 1 mil and about 3 mils.

### Claim 5 (depends on 4)

A multilayer film as in claim 4 wherein the thickness of said film is between about 1.3 and about 1.8 mils.

### Claim 6 (depends on 1)

A multilayer film as in claim 1 wherein the ratio of thicknesses between said core layer and said two outer layers is on the order of about 1:5:1.

### Claim 7 (depends on 1)

A multilayer film as in claim 1 wherein said film contains at least one colorant.

### Claim 8 (depends on 1)

A multilayer film as in claim 1 wherein said film is formed into a bag.