Long-Chain Branched Polyethylene Medical Container

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Solution Overview

Problem

Medical containers made of polyethylene resin generate acid substances during radiation sterilization, which can adversely affect the contents, particularly liquid medicines, and fail to meet the required standards for chemical resistance, gas barrier performance, and mechanical strength.

Innovation Solution

A medical container with an inner surface made of polyethylene resin having a long-chain branch structure, manufactured using an organic modified clay mineral catalyst and an organic aluminum compound, which suppresses the generation of acid substances during radiation sterilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polyethylene resin is used for medical container, then ease of manufacture and cost are improved, but acid substance generation during radiation sterilization increases

Engineering Contradiction:
Improveease of manufactureVSAvoidacid substance generation
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention changes the molecular structure parameter of polyethylene from conventional linear or short-chain branched structure to long-chain branched structure. This parameter change fundamentally alters the resin's behavior during radiation sterilization, suppressing acid substance generation while maintaining ease of manufacture and other desirable properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality by specifying that the inner surface layer (which contacts the medical content) must be made of long-chain branched polyethylene. This localized application of the special resin structure where it is most needed (at the inner surface) effectively prevents acid migration to contents while allowing other layers to use conventional resins for manufacturing efficiency.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If conventional polyethylene resin is used, then manufacturing cost is reduced, but chemical resistance and gas barrier performance deteriorate

Engineering Contradiction:
Improvemanufacturing costVSAvoidchemical resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention employs composite material structure with multiple layers having different functions. The inner surface layer uses long-chain branched polyethylene for chemical resistance and low acid generation, while outer layers can use conventional polyethylene for cost efficiency. This composite approach achieves both chemical resistance and economical manufacturing.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

By changing the molecular architecture parameter of polyethylene to long-chain branched structure, the invention simultaneously improves chemical resistance, gas barrier performance, and acid substance suppression while maintaining manufacturing feasibility through established blow molding processes.

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If radiation sterilization is applied, then sterilization time and cost are improved, but acid substance generation increases

Engineering Contradiction:
Improvesterilization timeVSAvoidacid substance generation
Core Design Contradiction:
Loss of timeVSObject-generated harmful factors

Solution Approach 1:

The invention changes the chemical composition parameter of the polyethylene resin to long-chain branched structure, which fundamentally alters the resin's stability under radiation. This parameter change enables the container to withstand radiation sterilization (achieving fast, low-cost sterilization) without generating harmful acid substances.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The long-chain branched polyethylene structure acts as a preliminary protective measure against acid generation during radiation sterilization. By pre-configuring the resin with this stable molecular structure before sterilization, the container is prepared to resist acid formation, allowing radiation sterilization to proceed without harmful byproducts.

Inventive Principle:
Principle #9Preliminary anti-action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The container maintains excellent chemical resistance, gas barrier performance, transparency, and mechanical strength while minimizing acid substance generation during radiation sterilization, ensuring the integrity of the contents.

Implementation Method 1

the sterilization treatment by radiation irradiation is coming into wider use

Methodology Applied
Scientific EffectRadiation sterilization: Radiation

Data Source

PatentEP2898872B1Medical container
Publication Date: 2018.08.15 KYORAKU CO LTD

AI summary

[Problem] A medical container that generates few acid substances even when subjected to a sterilization treatment by radiation irradiation is provided. [Solution] The medical container is subjected to a sterilization treatment by radiation irradiation. At least an inner surface of the medical container is made of a polyethylene resin having a long-chain branch structure. The medical container may be made of a blow molding product. Alternatively, the medical container may be made of a multi-layered molding product such that its inner and outer layers are made of a polyethylene resin having a long-chain branch structure.