Low-Temperature Silicone Adhesive Composition for Engineering Plastics

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Solution Overview

Problem

Conventional silicone adhesives lack sufficient adhesive strength for high-performance engineering plastics and cause dimensional deformation due to high-temperature curing processes.

Innovation Solution

A silicone composition comprising specific organopolysiloxanes and organohydrogen siloxanes, along with adhesion promoters and catalysts, allows for rapid curing at low temperatures, providing strong adhesion to plastics like polycarbonate, polyethylene terephthalate, and polymethyl methacrylate while minimizing deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional thermosetting silicone adhesive is used, then adhesive strength is insufficient for high-performance engineering plastics, but using conventional adhesives without functional groups also limits adhesion to such plastics

Engineering Contradiction:
Improveadhesive strengthVSAvoidcompatibility with high-performance engineering plastics
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent modifies the chemical structure of silicone adhesives by introducing functional groups (such as silane groups) that can chemically bond with high-performance engineering plastics like PC, PET, and PMMA. This changes the chemical parameters of the adhesive to enable specific interactions with plastic surfaces, thereby improving both adhesive strength and compatibility simultaneously.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite adhesive system by combining silicone base polymers with functional groups (e.g., silane-modified polymers). This composite structure integrates the flexible properties of silicone with the chemical bonding capability of functional groups, achieving both strong adhesion to plastics and maintained flexibility.

Inventive Principle:
Principle #40Composite materials

2Strength

If high-temperature curing process is used for thermosetting silicone adhesive, then adhesive strength is improved, but dimensional deformation of plastic substrate occurs

Engineering Contradiction:
Improveadhesive strengthVSAvoiddimensional stability of plastic substrate
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent changes the curing temperature parameter from high-temperature thermosetting processes to low-temperature curing (near room temperature). This parameter change enables the adhesive to cure without causing thermal deformation to plastic substrates while still achieving sufficient adhesive strength through the chemical bonding mechanism of the functional groups.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the thermal curing mechanism with a chemical bonding mechanism. Instead of relying on heat-induced crosslinking that causes dimensional changes, the adhesive uses functional groups (such as silane groups) that form chemical bonds with plastic surfaces at low temperatures, substituting thermal energy with chemical reactivity to achieve adhesion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If conventional silicone adhesive is used, then adhesion to general substrates is maintained, but adhesion to high-performance engineering plastics is insufficient

Engineering Contradiction:
Improvegeneral substrate adhesionVSAvoidadhesive strength to engineering plastics
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent develops a universal adhesive formulation that incorporates functional groups capable of bonding with multiple substrate types, including high-performance engineering plastics. The adhesive maintains its ability to adhere to general substrates while adding specific chemical bonding capability for plastics through the incorporated functional groups, achieving multi-functionality in a single formulation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 exhibits stable adhesion and rapid curing, suitable for bonding and assembly of electronic and automotive components, with excellent heat resistance and stress relief properties, particularly beneficial for outdoor displays and curved designs.

Implementation Method 1

a first organopolysiloxane including a C2 to C20 alkenyl group bonded to at least one Si at both ends or a chain

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

an organohydrogen siloxane comprising at least two SiH functional groups per molecule

Methodology Applied
Scientific EffectHydrosilylation: Chemical Bonding

Implementation Method 3

a high stability as an interlayer adhesive material by virtue of its characteristics due to the flexible structure such as low shrinkage rate and stress relief function

Methodology Applied
Scientific EffectStress Relaxation: Stress Relaxation

Data Source

PatentUS20260055239A1Silicone compositions
Publication Date: 2026.02.26 WACKER CHEMIE AG

AI summary

The present disclosure provides a silicone composition including: (a1) a first organopolysiloxane including a C2 to C20 alkenyl group bonded to at least one Si at both ends or a chain, the first organopolysiloxane formed from a unit represented by (R3SiO1/2)a(R2SiO2/2)b(RSiO3/2)c(SiO4/2)d (wherein a is in a range of 1 to 50, b is in a range of 100 to 500, c is in a range of 0 to 50, and d is in a range of 0 to 50); (a2) a second organopolysiloxane including a C2 to C20 alkenyl group bonded to at least one Si at both ends or a chain, and including at least one unit represented by SiO4/2; and (b) an organohydrogen siloxane comprising at least two SiH functional groups per molecule and comprising at least one C6 to C20 aryl group.