Alkoxylated Polydimethylsiloxane Additive for Moulded Polyurethane Foam Demoulding
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Solution Overview
Problem
Existing release agents for moulded polyurethane foams face challenges such as adhesion to moulds, instability in formulation, interference with cellular structure, and unsatisfactory lubrication, leading to difficulties in demoulding and surface quality issues.
Innovation Solution
A new additive defined by the formula MeO(CH2CH2O)nCH2CH2CH2SiMe2O[SiMe2O]8SiMe2CH2CH2CH2(OCH2CH2)nOMe (n=6-7) is developed, which enhances demoulding properties and lubrication by improving compatibility with waxes, reducing residue, and providing conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal release agents (organopolysiloxanes with carboxyl groups) are used to improve releasability, then the polyurethane system gelling time is prolonged and stable mixtures with polyols cannot be formed
Solution Approach 1:
The patent changes the chemical parameters of the release agent by using siloxane compounds with specific functional groups (known from U.S. Pat. No. 4,076,695) that have different reactivity characteristics. These modified parameters allow the release agent to function without excessively prolonging the gelling time, thus resolving the contradiction between improving releasability and maintaining acceptable curing speed.
2Reliability
If internal release agents are used to improve demoulding, then the cellular structure development is hindered and foam collapse may occur
Solution Approach 1:
The patent extracts the release agent function from the internal polyol component and places it in the external mould release composition instead. This separation allows the internal polyol system to maintain its cellular structure stability while the external composition provides the demoulding function, thus resolving the contradiction between demoulding effectiveness and cellular structure integrity.
3Force
If conventional release agents are used to reduce adhesion, then lubrication is insufficient and surface quality issues occur
Solution Approach 1:
The patent uses a composite release composition containing siloxane compounds with specific functional groups combined with other compatible ingredients. This composite formulation provides both adequate lubrication for easy demoulding and maintains surface quality by preventing defects like orange peel effects, thus resolving the contradiction between reducing adhesion and maintaining surface 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
The additive achieves smooth demoulding with minimal force, maintains cellular structure integrity, and ensures high surface quality without orange peel effects, while being highly compatible with polyurethane systems.
Implementation Method 1
The additive achieves smooth demoulding with minimal force
Implementation Method 2
Release agents are used wherever the adhesion of moulding materials to the moulds is so great that non-destructive removal of the moulded part is not possible
Data Source
AI summary
An additive for a release agent for moulded polyurethane foams, having the structure of alkoxylated polydimethylsiloxane. Also, a process for preparing the additive, to a release composition including the additive. Further, a process for making a moulded polyurethane foam using a composition including the additive, and to the use of the additive and the release composition for making a moulded polyurethane foam.