Polyrotaxane Composition Transparency via Alkyl Group Modification
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Solution Overview
Problem
Polyrotaxane-containing compositions, such as thermosetting urethane elastomers and pressure-sensitive adhesives, face issues with transparency and weather resistance when used with long-chain alkyl (meth)acrylates, leading to turbidity due to poor compatibility between polyrotaxanes and these materials.
Innovation Solution
Introducing a C4-C18 alkyl group into the cyclic molecule of polyrotaxanes improves their compatibility with long-chain alkyl (meth)acrylates, resulting in a composition with enhanced transparency and weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyrotaxane is used as a crosslinking agent for long-chain alkyl (meth)acrylate, then stress relaxation properties and hysteresis loss are improved, but transparency deteriorates due to turbidity
Solution Approach 1:
The patent changes the chemical structure parameters of the polyrotaxane by introducing long-chain alkyl groups (C4-C18) into the cyclic molecule. This parameter change modifies the compatibility between polyrotaxane and long-chain alkyl (meth)acrylate, preventing phase separation and maintaining transparency while preserving the stress relaxation properties provided by the polyrotaxane crosslinking structure.
Solution Approach 2:
The patent creates a composite system where polyrotaxane with modified cyclic molecules (containing C4-C18 alkyl groups) is combined with long-chain alkyl (meth)acrylate. This composite material achieves both the desired mechanical properties (stress relaxation, low hysteresis) and optical properties (transparency) by ensuring molecular-level compatibility between the crosslinking agent and the base polymer.
2Reliability
If a polyrotaxane is mixed with long-chain alkyl (meth)acrylate, then stress relaxation properties are improved, but compatibility deteriorates leading to turbidity
Solution Approach 1:
The patent modifies the compositional parameters of the polyrotaxane by incorporating C4-C18 alkyl groups into the cyclic molecule structure. This changes the hydrophobicity and molecular interactions, improving compatibility with long-chain alkyl (meth)acrylate and preventing composition instability or phase separation while maintaining the stress relaxation functionality.
3Ease of manufacture
If a solvent is used for mixing (meth) acrylic acid ester copolymer with polyrotaxane, then mixing is facilitated, but additional processing steps are required for solvent removal
Solution Approach 1:
The patent extracts and eliminates the solvent from the mixing process by designing a polyrotaxane composition that is directly compatible with long-chain alkyl (meth)acrylate. The modified polyrotaxane (with C4-C18 alkyl groups in cyclic molecules) can be mixed with the monomer without requiring external solvents, thereby removing the need for subsequent solvent removal steps and simplifying the overall manufacturing process.
Data Source
AI summary
The present invention aims to provide a polyrotaxane-containing composition having excellent transparency.The present invention relates to a polyrotaxane-containing composition including: a polyrotaxane that has a cyclic molecule, a linear molecule threading through a cavity of the cyclic molecule in a skewered manner, and capping groups capping both ends of the linear molecule; and an alkyl (meth) acrylate that has a C4-C18 alkyl group, the polyrotaxane having at least one cyclic molecule that has a C4-C18 alkyl group.