Solvent-Free Polyurethane Release Agent
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Solution Overview
Problem
Conventional release agents for polyurethane moldings, especially those solvent-based or water-based, face issues such as severe discoloration, environmental pollution, allergy risks, and the formation of resinous, sticky layers due to unsaturated hydrocarbons, which lead to polyurea build-up on mold surfaces and contamination of the working environment.
Innovation Solution
A mixture of classic separating waxes and oils without volatile solvents, specifically designed to be free of unsaturated hydrocarbons and volatile organic compounds, is used as a release agent, ensuring no water or VOCs are present, with a composition that includes at least 50% by weight of separating wax and up to 50% by weight of separating oil, along with optional auxiliaries and additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water is used as a solvent or carrier medium for separating substances, then environmental pollution with volatile organic material is reduced, but a thin film of water remains in the mold after evaporation that reacts with isocyanate compounds to form hard polyurea compounds and polyurea build-up on the mold surface
Solution Approach 1:
The invention extracts and eliminates water and volatile organic solvents from the release agent composition. The release agent consists essentially of non-volatile separating substances (waxes, oils, silicones) without any solvent carrier, thereby avoiding the formation of water films that react with isocyanates to form polyurea build-up on mold surfaces.
Solution Approach 2:
The invention changes the volatility parameter of the carrier medium by completely eliminating volatile components (water and organic solvents) and using only non-volatile separating substances. This parameter change prevents the formation of residual films that would react with polyurethane systems to create harmful build-up.
2Reliability
If unsaturated oligomeric or polymeric hydrocarbons with double bonds are used in release agents, then release effect is improved, but severe discoloration occurs due to oxidation of the double bonds and resinous, sticky layers form that are difficult to remove
Solution Approach 1:
The invention converts the harmful effect of oxidation-prone double bonds by completely excluding unsaturated hydrocarbons from the formulation. Instead of trying to protect the double bonds from oxidation, the solution is to use saturated hydrocarbons, silicones, and waxes that are inherently resistant to oxidation, thereby eliminating discoloration and resinous layer formation while maintaining release effectiveness.
Solution Approach 2:
The invention uses a composite composition of multiple non-volatile separating substances including waxes, saturated hydrocarbons, and silicones. This composite approach provides synergistic release effect while avoiding the oxidation problems associated with unsaturated hydrocarbons, as each component contributes to release performance without the harmful side effects.
3Reliability
If solvent-based release agents are used, then release effect and surface finish are maintained, but environmental pollution and contamination of the working environment occur
Solution Approach 1:
The invention extracts and removes volatile organic solvents from the release agent formulation. The release agent consists essentially of non-volatile separating substances without any solvent carrier, thereby eliminating environmental pollution and working environment contamination while maintaining effective release performance through the non-volatile components alone.
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
This solution prevents polyurea build-up on mold surfaces, reduces environmental contamination, minimizes discoloration and sticky layer formation, and lowers the risk of allergies, while maintaining a good release effect and smooth surface finish for polyurethane moldings.
Implementation Method 1
After the release agent has been applied to the mold, the solvent evaporates and the non-volatile release-active substances form a thin release film
Implementation Method 2
water always remains in the mold, which forms at the usual mold temperatures of 45 to 80 °C, preferably 50 up to 75 °C, does not volatilize and reacts with the isocyanate compounds of the polyurethane system, which lead to very hard polyurea compounds
Implementation Method 3
a particular disadvantage of these release agents is the severe discoloration that occurs, which is caused by oxidation of the double bonds
Data Source
AI summary
The invention relates to solvent-free release agents for the production of polyurethane molded bodies, comprising essentially A) at least one release-active wax, B) at least one release-active oil and C) optionally further auxiliary and additive substances, with the proviso that the release agent contains no water and no volatile organic solvents and the release-active oil is essentially free of unsaturated hydrocarbons.