Hot-Melt Organopolysiloxane Composition for Low-Temperature Clear Adhesion
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Solution Overview
Problem
Conventional hot-melt silicone compositions face challenges in achieving low-temperature curing, maintaining transparency, and ensuring adequate pressure-sensitive adhesive strength, particularly for applications requiring low heat resistance and reduced energy consumption.
Innovation Solution
A hot-melt curable organopolysiloxane composition comprising a chain organopolysiloxane with two or more alkenyl groups, an organopolysiloxane resin with a specific M to Q unit ratio, and a radical polymerization initiator, allowing for curing over a wide temperature range through heat or high-energy beam irradiation, ensuring excellent adhesion and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional hot-melt silicone compositions use high-temperature heat curing (exceeding 150°C), then sufficient curing reaction rate and physical strength are achieved, but deformation and degradation of organic resin with low heat resistance occur
Solution Approach 1:
The patent changes the curing temperature parameter from conventional high temperatures (>150°C) to low temperatures (room temperature or slightly elevated), enabling curing of organic resins without degradation while maintaining sufficient curing reaction rate through the use of radical polymerization initiators and alkenyl group-containing organopolysiloxane
Solution Approach 2:
The patent substitutes thermal curing mechanism with radical polymerization mechanism initiated by high-energy beam irradiation or chemical initiators, replacing the need for high-temperature heat curing with a chemical reaction-based curing process that occurs at low temperatures
2Productivity
If active energy beam-curable hot-melt silicone composition uses thiol-ene reaction, then quick curability at room temperature is achieved, but yellowing resistance deteriorates
Solution Approach 1:
The patent extracts the problematic thiol-ene reaction system and replaces it with a radical polymerization system using alkenyl group-containing organopolysiloxane and radical polymerization initiators, retaining the low-temperature curability benefit while eliminating the yellowing resistance drawback
Solution Approach 2:
The patent creates a composite curing system combining alkenyl group-containing organopolysiloxane with radical polymerization initiators, achieving both quick curability at room temperature and excellent yellowing resistance through the synergistic interaction of these components
3Strength
If conventional hot-melt silicone compositions are designed for high-temperature curing, then excellent physical strength and durability are achieved, but handling workability of overmolding and transparency deteriorate at low temperatures
Solution Approach 1:
The patent creates a dynamic curing system that can adapt to different temperature conditions, maintaining excellent physical strength and durability while providing good handling workability at low temperatures through the use of room-temperature-curable radical polymerization initiators and alkenyl group-containing organopolysiloxane
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 enables favorable curing at low temperatures, maintains transparency, and provides strong adhesion and durability, making it suitable for various sealing and adhering processes, including semiconductor devices, with improved handling workability and energy efficiency.
Implementation Method 1
a hot-melt curable organopolysiloxane composition containing (A) 1 to 50 parts by mass of a chain organopolysiloxane having two or more alkenyl groups in a molecule, (B) 50 to 99 parts by mass of an organopolysiloxane resin containing an M unit expressed by R3SiO1/2 and a siloxane unit (Q unit) expressed by SiO4/2, and (C) 0.1 to 10 parts by mass of a radical polymerization initiator
Implementation Method 2
curing over a wide temperature range through heat or high-energy beam irradiation
Data Source
AI summary
Provided is a hot-melt silicone composition that can be cured at various temperatures, that enables the design of the pressure-sensitive adhesive strength of a resulting cured product to a base material over a wide range, that has excellent transparency and yellowing resistance, and that has excellent handling workability. The composition comprises (A) 1 to 50 parts by mass of a chain organopolysiloxane having two or more alkenyl groups in a molecule, (B) 50 to 99 parts by mass of an MQ organopolysiloxane resin in which the molar ratio of M units to 1 mol of Q units is in the range of 0.5 to 2.0, and (C) 0.1 to 10 parts by mass of a radical polymerization initiator. Optionally, the composition comprises (D) another radical reactive component. The amount of component (B) is 50 mass % or more with respect to the total mass of the solid fraction of the composition.