Hollow Particle Elastomer Composition for Preventing Kneading Collapse
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Solution Overview
Problem
Existing elastomer compositions incorporating hollow particles face challenges in maintaining dimensional stability and preventing particle collapse during kneading and molding, leading to deteriorated properties and functions.
Innovation Solution
A hollow particle-containing elastomer composition with a shell made of a resin containing 50 parts by mass or more crosslinkable monomer units, having a storage elastic modulus of 2.5 MPa or less, is produced by preliminary kneading at a controlled temperature to minimize shear force, ensuring high dimensional stability and retention of hollow particle properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-shear kneading such as roll kneading is carried out for finishing kneading of hollow particles and base material elastomer, then mixing efficiency is improved, but hollow particles are likely to collapse during kneading
Solution Approach 1:
The kneading process is divided into two distinct stages: preliminary kneading (low shear force) and finishing kneading (high shear force). This segmentation allows the hollow particles to be gently incorporated first, then thoroughly mixed without excessive collapse, resolving the contradiction between mixing efficiency and particle integrity.
Solution Approach 2:
Preliminary kneading is performed before finishing kneading to pre-mix the hollow particles with the base material elastomer under low shear conditions. This preliminary action protects the hollow particles from collapse before the high-shear finishing kneading step, maintaining both particle integrity and eventual mixing efficiency.
2Weight of moving object
If hollow particles are incorporated in base material elastomer to reduce weight and provide heat insulation, then weight reduction and heat insulation properties are improved, but hollow particles are likely to collapse during molding
Solution Approach 1:
The hollow particles undergo preliminary kneading under low shear conditions before the molding process. This preliminary action prepares the mixture in a way that minimizes particle collapse during subsequent molding, ensuring both weight reduction benefits and particle stability are maintained.
Solution Approach 2:
The kneading temperature is controlled within a specific range (50-100°C for preliminary kneading, -50-100°C for finishing kneading) to optimize the viscosity and flow characteristics of the base material elastomer. This parameter control reduces shear stress on hollow particles during processing while maintaining mixing efficiency and preventing collapse during molding.
3Productivity
If conventional kneading temperature ranges are used for mixing hollow particles and base material elastomer, then processing efficiency is improved, but hollow particles collapse and dimensional stability deteriorates
Solution Approach 1:
The patent specifies precise temperature ranges for different kneading stages: preliminary kneading at 50-100°C and finishing kneading at -50-100°C. These controlled temperature parameters optimize the base material elastomer's viscosity to minimize hollow particle collapse while maintaining efficient processing, thereby achieving both productivity and dimensional stability.
Solution Approach 2:
The kneading process is segmented into temperature-controlled stages with different objectives. Preliminary kneading uses controlled temperatures to protect particles, while finishing kneading optimizes mixing efficiency. This segmented approach resolves the contradiction between processing efficiency and dimensional stability.
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 composition maintains high dimensional stability and retains the functional properties of hollow particles, preventing collapse during kneading and molding, while achieving a residual void ratio of 80% or more.
Implementation Method 1
the shell comprising a resin which is a polymer containing 50 parts by mass or more of a crosslinkable monomer unit in 100 parts by mass of all monomer units
Implementation Method 2
a base material elastomer is mixed with a foaming agent, and the mixture is foamed by heating in a molding step, thereby obtaining a foamed elastomer molded body
Data Source
AI summary
Provided are a hollow particle-containing elastomer composition in which high dimensional stability is retained in the molding step, and properties/functions of the hollow particles are less likely to deteriorate; and a method for production thereof in which the hollow particles are less likely to collapse in the kneading step. The provided elastomer composition comprises a base material and hollow particles comprising a specific resin, and has a storage elastic modulus G′ at 60° C. of 2.5 MPa or less; and also has a residual void ratio of 80% or more which is measured by a predetermined method. In the provided method, a raw material mixture is kneaded in both steps of preliminarily kneading and finishing kneading at a temperature at which the storage elastic modulus G′ becomes 2.5 MPa or less.