Organopolysiloxane Release Modifier for Stable Heavy Release Force
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Solution Overview
Problem
Existing release coating compositions for pressure-sensitive adhesive tapes and labels face issues with temporal stability of release force, migration of coating components into the adhesive layer, increased viscosity, and difficulty in microadjusting release force, while also being costly due to the use of expensive materials like alkenyl-functional MQ resin.
Innovation Solution
A release modifier comprising an organopolysiloxane resin-organopolysiloxane condensation reaction product with specific hydroxyl group content and molar ratios, combined with a silylating agent, is used to create a composition that provides a heavy release effect with stable viscosity and minimal migration, allowing for easy adjustment of release force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a tacky polyorganosiloxane resin component is added to increase release force, then the release force is improved, but the viscosity increases and component migration into the adhesive layer occurs
Solution Approach 1:
The patent changes the chemical parameters of the polyorganosiloxane resin by controlling the molar ratio of hydroxyl-functional units to alkenyl-functional units, and by controlling the degree of condensation reaction. This allows achieving the desired release force while maintaining acceptable viscosity levels. Specifically, the patent specifies that the condensation reaction product should have a hydroxyl group content of 0.01-5 weight% and use a molar ratio of hydroxyl-functional units to alkenyl-functional units of 0.9-1.1, which optimizes both release force and viscosity.
Solution Approach 2:
The patent creates a composite release modifier by combining the condensation reaction product of hydroxyl-functional polyorganosiloxane with alkenyl-functional polyorganosiloxane. This composite material integrates the heavy release properties of the condensation product with the viscosity control and compatibility benefits of the alkenyl-functional component, achieving a balance between release force and viscosity.
2Force
If a condensation product of hydroxyl-functional polyorganosiloxane with hydroxyl-functional polydimethylsiloxane is used to provide heavy release, then the release force is improved, but the composition exhibits increased viscosity
Solution Approach 1:
The patent controls the viscosity by adjusting the molecular weight and structure of the polydimethylsiloxane component used in the condensation reaction. Specifically, the patent specifies using polydimethylsiloxane with a viscosity of 10-1000 mPa·s and controls the hydroxyl group content of the condensation product to 0.01-5 weight%. These parameter changes allow achieving heavy release force while keeping the composition viscosity within acceptable ranges for practical application.
3Force
If known release modifiers are used to achieve heavy release behavior, then the release force is improved, but the release force lightens with the passage of time (lack of temporal stability)
Solution Approach 1:
The patent creates a composite release modifier system combining the condensation reaction product of hydroxyl-functional polyorganosiloxane with alkenyl-functional polyorganosiloxane. This composite structure provides temporal stability because the alkenyl-functional component forms a stable crosslinked network upon curing, which maintains the release force characteristics over time. The specific molar ratio control (0.9-1.1) ensures stable network formation that prevents degradation of release force properties during storage and service.
4Reliability
If alkenyl-functional MQ resin is used as starting material for release modifiers, then the release properties are improved, but the cost increases
Solution Approach 1:
The patent changes the starting material from expensive alkenyl-functional MQ resin to a combination of hydroxyl-functional polyorganosiloxane and polydimethylsiloxane. By controlling the condensation reaction parameters and the molar ratio of functional groups, the patent achieves comparable or superior release properties using more cost-effective raw materials. The patent specifies using polyorganosiloxane with hydroxyl groups and polydimethylsiloxane in controlled amounts to achieve the desired release characteristics without relying on expensive specialized resins.
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 solution achieves a stable and adjustable heavy release effect with low viscosity, reducing component migration and improving handling properties, while utilizing readily available and cost-effective raw materials.
Implementation Method 1
an organopolysiloxane resin-organopolysiloxane condensation reaction product obtained by the condensation reaction of (a1) 100 weight parts of organopolysiloxane resin essentially comprising the R1
Implementation Method 2
combined with a silylating agent, is used to create a composition that provides a heavy release effect with stable viscosity and minimal migration
Data Source
AI summary
To provide a release modifier which provides a heavy release force to a cured release layer of silicone coating composition. The release modifier comprises an organopolysiloxane resin-organopolysiloxane condensation reaction product that is obtained by the condensation reaction of (a1) 100 weight parts of MQ-type organopolysiloxane resin in which the molar ratio of the M unit to the Q unit is 0.6 to 1.0 and the content of the hydroxyl group or alkoxy group is 0.3 to 2.0 weight% with (a2) 20 to 150 weight parts of chain-form diorganopolysiloxane that has an average degree of polymerization of 100 to 1000 and at least one hydroxyl group or alkoxy group; this organopolysiloxane resin-organopolysiloxane condensation reaction product preferably has a prescribed hydroxyl group content.