Multilayered Liquid Container Discharge Port Welding

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Solution Overview

Problem

Multilayered liquid containers face challenges in preventing effective components of a content fluid from adsorption or penetration into both the container body and discharge port resins, while also requiring high-temperature sterilization resistance and robust weld and drop strength.

Innovation Solution

A multilayered liquid container design featuring a discharge port with an innermost layer of cycloolefin resin and a surface layer of metallocene-catalyzed polyethylene, where the cycloolefin resin is exposed as a band at the welded surface, providing high weld strength and impact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a discharge port member is formed entirely of COP resin to ensure compatibility with the innermost layer, then weld strength is improved, but the structure becomes brittle and prone to breakage upon impact

Engineering Contradiction:
Improveweld strengthVSAvoidimpact resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The discharge port member is constructed as a composite structure with an innermost layer of COP resin for chemical compatibility and weld strength, and an outer layer of flexible resin (such as polyolefin) for impact resistance. This composite approach allows each material to contribute its advantageous properties to the overall structure.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different regions of the discharge port member have different material compositions tailored to their specific functional requirements. The innermost layer contacting the fluid uses COP resin for compatibility, while the outer layer uses flexible resin for mechanical protection, creating local quality variations that optimize overall performance.

Inventive Principle:
Principle #3Local quality

2Reliability

If polyethylene resin is used as the innermost layer to improve flexibility and drop impact strength, then mechanical durability is improved, but component adsorption and interaction with content fluid increases

Engineering Contradiction:
Improvedrop impact strengthVSAvoidcomponent adsorption
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The container wall and discharge port are segmented into multiple layers with distinct functions. The innermost layer is dedicated to fluid contact with COP resin for chemical inertness, while the outer layers provide mechanical flexibility and impact resistance, separating the chemical barrier function from the mechanical protection function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A multilayered composite structure combines COP resin (for chemical compatibility) with flexible polyethylene or polyolefin resins (for mechanical durability and flexibility). This composite construction allows the system to achieve both non-adsorptive properties and impact resistance simultaneously.

Inventive Principle:
Principle #40Composite materials

3Object-generated harmful factors

If COP resin is used throughout the discharge port structure to maintain chemical compatibility, then prevention of medicinal adsorption is improved, but manufacturing cost increases due to higher resin price and greater material consumption

Engineering Contradiction:
Improvemedicinal adsorptionVSAvoidmanufacturing cost
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The COP resin is extracted from the entire discharge port structure and applied only where it is most critical - in the innermost layer that directly contacts the medicinal solution. The outer layers use more economical flexible resins, reducing overall material cost while maintaining chemical compatibility where it matters most.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

COP resin is applied locally only to the innermost layer requiring chemical compatibility, rather than throughout the entire discharge port structure. This localized application minimizes the quantity of expensive COP resin used while maintaining effectiveness at the critical fluid-contact interface.

Inventive Principle:
Principle #3Local quality

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

Prevents fluid component adsorption and penetration into both the container body and discharge port, enables high-temperature sterilization, and achieves strong weld and drop resistance, ensuring the container's integrity and functionality.

Implementation Method 1

an innermost layer forming a discharge path of the discharge port is constituted of a resin including a cycloolefin resin as a main component... preventing effective components of a content fluid from adsorption on or penetration through the container body and discharge port

Methodology Applied
Scientific EffectAdsorption prevention: Adsorption

Implementation Method 2

a main part of a surface layer is constituted of a resin including, as a main component, polyethylene polymerized by use of a metallocene catalyst... high drop strength

Methodology Applied
Scientific EffectImpact resistance: Impact Force

Implementation Method 3

the discharge port is welded with a sealant composed of a resin including a cycloolefin resin as a main component... high weld strength

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP2330048B1Multilayered liquid container
Publication Date: 2013.07.03 FUJIMORI KOGYO CO LTD
  • EP2330048B1 patent drawingFigure 1
  • EP2330048B1 patent drawingFigure 2~3
  • EP2330048B1 patent drawingFigure 4~5

AI summary

A multilayered liquid container having a discharge port welded under specified conditions to a sealant, which is constituted of a resin comprising a cycloolefin resin as a main component. The discharge port is composed of: an innermost layer constituted of a resin comprising a cycloolefin as a main component; and a surface layer whose main part is constituted of a resin comprising a specific type of polyethylene as a main component. According to the present invention, there can be provided a multilayered liquid container, which can prevent an effective component of a content fluid from being adsorbed onto or penetrating through not only the container body, but also the resin constituting the discharge port, and enables high temperature sterilization treatment, coupled with the discharge port having high welded strength and drop strength.