Curable Composition Adhesiveness Viscosity Trade-off
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Solution Overview
Problem
Current curable compositions with reactive silicon groups face challenges in achieving broad adhesiveness to various substrates while maintaining low viscosity, as high Tg polymers can improve adhesiveness but increase viscosity, leading to poor workability.
Innovation Solution
A curable composition comprising a (meth)acrylic acid ester polymer with a reactive silicon group, specifically designed to have a low viscosity and high molecular weight, combined with an oxyalkylene polymer, to enhance adhesiveness and workability across a range of substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a (meth)acrylic acid ester polymer with high Tg is used to increase adhesiveness, then adhesiveness to adherends is improved, but viscosity of the composition increases leading to poor workability
Solution Approach 1:
The patent changes the molecular weight parameter of the (meth)acrylic acid ester polymer to a specific range (1,000 to 100,000) to optimize the balance between adhesiveness and viscosity. This parameter optimization allows the polymer to provide sufficient adhesive strength while maintaining acceptable workability, resolving the contradiction between these two properties.
Solution Approach 2:
The patent creates a composite curable composition by combining (meth)acrylic acid ester polymer with reactive silicon group-containing polyoxyalkylene polymer and other components. This composite approach allows the composition to achieve broad adhesiveness through synergistic effects while controlling viscosity through the specific molecular weight selection and formulation, thus resolving the contradiction between adhesiveness and workability.
2Reliability
If a polymer with high molecular weight is used to improve adhesiveness, then adhesiveness is improved, but viscosity increases leading to poor workability
Solution Approach 1:
The patent specifies a precise molecular weight range (1,000 to 100,000) for the (meth)acrylic acid ester polymer to optimize the balance between adhesiveness and viscosity. This parameter control ensures that the polymer provides sufficient adhesive strength without causing excessive viscosity that would impair workability.
Solution Approach 2:
The patent applies different functional requirements to different components: the (meth)acrylic acid ester polymer with specific molecular weight provides adhesiveness, while the reactive silicon group-containing polyoxyalkylene polymer contributes to workability and curing. This localized functional assignment allows each component to optimize its contribution without compromising the other.
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 achieves favorable adhesiveness to various substrates with low viscosity, improving workability and maintaining mechanical properties of the cured product.
Implementation Method 1
an organic polymer having a reactive silicon group which has a hydroxyl group or a hydrolyzable group on a silicon atom
Implementation Method 2
crosslinked by siloxane condensation reaction of a reactive silicon group
Implementation Method 3
form a siloxane bond
Data Source
AI summary
The present invention relates to a curable composition which contains a (meth)acrylic acid ester polymer (A) having as constituent monomers a monomer having a reactive silicon group represented by the general formula (1): -SiR1aX3-a (1) (in the formula, R1 represents a substituted or unsubstituted hydrocarbon group with 1 to 20 carbon atoms, X each independently represents a hydroxyl group or a hydrolyzable group, and a represents 0 or 1) and a polymerizable unsaturated group, and a macromonomer (a) having a polymerizable unsaturated group, in which the macromonomer (a) is a (meth)acrylic acid ester polymer, the hydrolyzable group is a hydrogen, a halogen, an alkoxy group, an alkenyloxy group, an aryloxy group, an acyloxy group, an amino group, an amide group, an aminooxy group, or a mercapto group, and Tg of a stem chain constituting the polymer (A) is 0°C to 130°C.