Metallocene Polyethylene Film Strength and Processability

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Solution Overview

Problem

Polyethylene-based resin films containing calcium carbonate suffer from inferior bag-making processability and film strength, limiting their usability in packaging applications.

Innovation Solution

A polyethylene-based resin composition incorporating an ethylene-α-olefin copolymer polymerized with a metallocene-based catalyst, combined with an inorganic compound like calcium carbonate, ensures excellent moldability and film strength, with specific ratios of resin and inorganic compound optimizing bag-making processability and film properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If calcium carbonate is added to reduce resin usage, then resin consumption is reduced, but bag-making processability deteriorates

Engineering Contradiction:
Improveresin consumptionVSAvoidbag-making processability
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The invention changes the chemical composition parameters of the resin by introducing a specific copolymer (ethylene-vinyl alcohol copolymer) with controlled vinyl alcohol content (30-80 mass%) and copolymerization ratio (20-70 mass%). This parameter adjustment allows the film to maintain good heat sealing properties and bag-making processability even with 20-60 mass% calcium carbonate addition, thus reducing resin consumption while preserving manufacturability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system consisting of calcium carbonate (inorganic filler), ethylene-vinyl alcohol copolymer (functional polymer), and polyethylene (base resin). This composite structure leverages the heat-resistant properties of the copolymer to compensate for the heat sealing issues caused by calcium carbonate, achieving both reduced resin usage and maintained processability

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If calcium carbonate is added to reduce resin usage, then resin consumption is reduced, but film strength deteriorates

Engineering Contradiction:
Improveresin consumptionVSAvoidfilm strength
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The invention adjusts the vinyl alcohol content parameter in the ethylene-vinyl alcohol copolymer to be within 30-80 mass%, which provides optimal balance between heat resistance and film strength. Additionally, the copolymerization ratio is controlled at 20-70 mass%, ensuring sufficient polymer matrix continuity to maintain film strength even with high calcium carbonate content (20-60 mass%), thereby reducing resin consumption without sacrificing mechanical properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite material system combines calcium carbonate particles with the ethylene-vinyl alcohol copolymer matrix, where the copolymer's molecular structure and intermolecular forces provide reinforcement to the film. The specific composition ratios create a synergistic effect where the inorganic filler and organic polymer work together to maintain film strength while reducing overall resin consumption

Inventive Principle:
Principle #40Composite materials

3Quantity of substance

If inorganic compound is added to ensure moldability, then resin usage is reduced, but bag-making processability deteriorates

Engineering Contradiction:
Improveresin usageVSAvoidbag-making processability
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The invention modifies the resin composition parameters by incorporating ethylene-vinyl alcohol copolymer with specifically controlled vinyl alcohol content (30-80 mass%) and copolymerization ratio (20-70 mass%). These parameter changes enhance the film's thermal and mechanical properties, enabling good heat sealing and bag-making processability even with 20-60 mass% inorganic compound addition, thus reducing resin usage while maintaining operational ease

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention develops a composite material comprising inorganic compound (calcium carbonate), ethylene-vinyl alcohol copolymer, and polyethylene. The copolymer component provides heat-resistant properties that compensate for the heat sealing deficiencies caused by inorganic fillers, creating a synergistic composite that achieves both reduced resin usage and preserved bag-making processability

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS20230331967A1Polyethylene-based-resin composition, polyethylene-based-resin packaging material, and method for producing same
Publication Date: 2023.10.19 SANIPAK OF JAPAN

AI summary

An object of the present invention is to provide a polyethylene-based resin composition from which a film can be obtained which has excellent moldability even in a case where an inorganic compound is added, and has excellent bag-making processability and film strength; and a polyethylene-based resin packaging material formed of the polyethylene-based resin composition. In a polyethylene-based resin composition containing an inorganic compound and an ethylene-α-olefin copolymer, the amount of a resin component is 25% by mass or more and less than 90% by mass, a proportion of the ethylene-α-olefin copolymer in the resin component is 50% by mass or more, and a proportion of an ethylene-α-olefin copolymer A polymerized with a metallocene-based catalyst in the ethylene-α-olefin copolymer is 10% by mass or more.