Isobutylene Rubber Compound with Polyolefin for High-Temperature Sterilization

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Solution Overview

Problem

Conventional pharmaceutical/medical rubber compounds face issues with deformation under high temperatures, insufficient mechanical properties, high water absorption, reactivity, and inadequate gas barrier properties, particularly in sterilization processes.

Innovation Solution

A pharmaceutical/medical rubber compound is developed by crosslinking an isobutylene polymer with a hydrosilyl-containing compound in the presence of polyolefin and polybutene, combined with ultra-high molecular weight polyethylene powder and a styrene-based thermoplastic elastomer, which allows for improved mechanical properties and resistance to high-temperature sterilization without deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional thermoplastic elastomers are used for pharmaceutical/medical rubber compounds, then moldability and economy are improved, but permanent set resistance under high temperature conditions deteriorates

Engineering Contradiction:

ImprovemoldabilityVSAvoidpermanent set resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the chemical structure parameters of the elastomer by using a block copolymer with specific architecture (hard segment glass transition temperature -40°C or lower, soft segment glass transition temperature -70°C or lower) and controlled molecular weight ratios, achieving both good moldability and high permanent set resistance without requiring crosslinking agents

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system combining polyolefin and polybutene in specific ratios (polybutene content: 1-50 parts by weight per 100 parts of polyolefin) to achieve synergistic effects that provide both processability and thermal stability, resolving the contradiction between ease of manufacture and reliability

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If conventional thermoplastic elastomers are used, then processing simplicity is improved, but mechanical properties and rubber elasticity deteriorate

Engineering Contradiction:

Improveprocessing simplicityVSAvoidmechanical properties

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The invention optimizes the glass transition temperatures of hard and soft segments, and controls the molecular weight and composition ratios, to achieve a balance between processing simplicity and excellent mechanical properties including high rubber elasticity and tensile strength

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional thermoplastic elastomers are used, then manufacturing cost is reduced, but gas barrier properties and water absorption resistance deteriorate

Engineering Contradiction:

Improvemanufacturing costVSAvoidgas barrier properties

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention uses a composite system of polyolefin and polybutene where polybutene provides excellent gas barrier properties and low water absorption, while maintaining cost-effectiveness through optimized composition ratios and simple processing requirements

Inventive Principle:

Principle #40Composite materials

4Ease of manufacture

If block copolymers are used to improve moldability, then crosslinking step is eliminated, but permanent set under stress at high temperatures worsens

Engineering Contradiction:

ImprovemoldabilityVSAvoidpermanent set

Core Design Contradiction:

Ease of manufactureVSShape

Solution Approach 1:

The invention changes the fundamental approach from chemical crosslinking to physical network formation through carefully controlled block copolymer architecture, where the hard segment acts as physical crosslinking points, providing both moldability and shape stability at high temperatures

Inventive Principle:

Principle #35Parameter changes

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 compound exhibits excellent mechanical properties, low water absorption, low reactivity, and superior gas barrier properties, maintaining shape and functionality even under high-temperature conditions, including resistance to autoclave sterilization.

Implementation Method 1

crosslinking (a) 100 parts by weight of an isobutylene polymer having terminal alkenyl groups with (d) a hydrosilyl-containing compound in the presence of (b) from 5 to 100 parts by weight of a polyolefin and (c) from 5 to 100 parts by weight of polybutene during melt kneading

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentEP2172515B1Rubber compound and molded article

Publication Date: 2012.06.06 DAIKYO SEIKO LTD

AI summary

A pharmaceutical/medical rubber compound contains the following components: (A) a composition obtainable by crosslinking (a) 100 parts by weight of an isobutylene polymer having terminal alkenyl groups with (d) a hydrosilyl-containing compound in the presence of (b) from 5 to 100 parts by weight of a polyolefin and (c) from 5 to 100 parts by weight of polybutene during melt kneading, and (B) an ultra-high molecular weight polyethylene powder. Compared with conventional thermoplastic elastomers, the pharmaceutical/medical rubber compound and its molded article are free from deformations and have sufficient permanent set resistance even under high temperature conditions, have excellent mechanical properties, low water absorption property, low reactivity and superb gas barrier properties, and can withstand high-temperature sterilization.