Organopolysiloxane Release Agent for Plastic Cracking
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Solution Overview
Problem
Existing release agents for plastics used in food containers and wraps face challenges with dilution stability, mechanical stability, and wettability, often leading to cracking issues, especially with plastics like OPS and PS, and do not meet safety standards for food contact as per the Japan Hygienic Olefin and Styrene Plastics Association's positive list.
Innovation Solution
A release agent comprising an organopolysiloxane emulsion with specific components such as anionic surfactants, polyoxyethylene alkyl ethers, polyoxyethylene sorbitan fatty acid esters, and sorbitan fatty acid esters, formulated to achieve an average particle size of 200 nm or less, ensuring excellent dilution and mechanical stability, and favorable wettability without causing stress cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an organopolysiloxane emulsion is diluted with water for application, then the concentration becomes suitable for coating (0.1 to 5.0%), but dilution stability deteriorates causing gel formation and oil floating
Solution Approach 1:
The patent introduces a specific nonionic surfactant (polyoxyethylene alkyl ether with m=12-20 and n=4-50) as an intermediary substance to stabilize the emulsion during dilution. This surfactant acts as a mediator between water and organopolysiloxane, preventing gel formation and oil floating while maintaining the required concentration range for application.
Solution Approach 2:
The patent optimizes the HLB value parameter of the nonionic surfactant within a specific range (13-17) to achieve optimal dilution stability. By controlling this physical parameter, the emulsion maintains stability across the required concentration range from 0.1% to 5.0% organopolysiloxane.
2Ease of operation
If vigorous stirring is used for rotor damping application, then the composition is well mixed and applied evenly, but the emulsion structure is destroyed causing gel formation and oil floating
Solution Approach 1:
The patent creates a composite emulsion system combining organopolysiloxane with a specifically designed nonionic surfactant mixture. This composite structure provides both ease of application and mechanical stability, allowing vigorous stirring for even distribution without emulsion breakdown.
Solution Approach 2:
The nonionic surfactant acts as a protective intermediary that shields the emulsion structure during mechanical processing. It allows vigorous stirring necessary for good application while preventing the destruction of the emulsion that would lead to gel formation and oil floating.
3Stability of the object's composition
If a large amount of nonionic surfactant is used to improve wettability and stability, then the emulsion is more stable and wets plastic better, but cracks occur in the plastic molding
Solution Approach 1:
The patent precisely controls the HLB value parameter of the nonionic surfactant within the range of 13-17, and limits the surfactant concentration to 1.0-30.0 parts by mass per 100 parts organopolysiloxane. This parameter optimization provides sufficient wettability and stability while preventing the excessive surfactant penetration that causes cracking in OPS and PS plastics.
Solution Approach 2:
The patent tailors the surfactant properties (specific HLB value range) to match the specific plastic substrate requirements. Different HLB values within the 13-17 range can be selected based on the specific plastic type, providing local optimization for each application to avoid cracking while maintaining stability.
4Ease of manufacture
If the average particle size is made large (200 nm or more), then the emulsion is easier to manufacture, but dilution stability and mechanical stability become poor
Solution Approach 1:
The patent controls the particle size parameter within the range of 50-200 nm by optimizing emulsification conditions and surfactant selection. This parameter control achieves a balance where particles are small enough to ensure excellent dilution and mechanical stability, yet large enough to be practically manufacturable with standard equipment.
Data Source
AI summary
A release agent for plastic contains the following components (A) to (E) and has an average particle size of 200 nm or less: (A) 100 parts by mass of an organopolysiloxane having a viscosity at 25° C. of 100 to 100,000 mm2/s; (B) 0.1 to 15.0 parts by mass of one or more anionic surfactants; (C) 1.0 to 30.0 parts by mass of a polyoxyethylene alkyl ether; (D) 0.5 to 15.0 parts by mass of a polyoxyethylene sorbitan fatty acid ester; and (E) 50 to 100,000 parts by mass of water. The release agent is an organopolysiloxane emulsion having excellent dilution stability and mechanical stability and favorable wettability, and hardly cracking plastic.