Silicone Emulsion Adhesion to Plastic Film via Silane Coupling
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Solution Overview
Problem
Existing silicone emulsion compositions face challenges in achieving satisfactory adhesiveness to plastic film substrates while maintaining suitable release properties, particularly due to high surface tension and poor wettability associated with water-based emulsions.
Innovation Solution
An addition reaction-curable silicone emulsion composition is developed, comprising a water-soluble silane coupling agent, an organopolysiloxane with alkenyl groups, an organohydrogenpolysiloxane, and polyvinyl alcohol, which enhances adhesiveness and release properties by improving film formation and substrate interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If emulsion type silicone is used to reduce solvent usage, then environmental safety is improved, but adhesiveness to plastic film substrate deteriorates due to high surface tension of water
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance between the water-based silicone emulsion and the plastic film substrate. The silane coupling agent contains both hydrophilic groups (that interact with water) and hydrophobic groups (that interact with the plastic substrate), thereby bridging the interface between the emulsion and substrate to improve adhesiveness while maintaining the environmental benefits of water-based formulation
Solution Approach 2:
The surface tension parameter of the water-based emulsion is modified by adding surfactants and silane coupling agents. These additives change the physical-chemical parameters of the emulsion system, reducing surface tension and improving wetting properties on the plastic film substrate, thereby enhancing adhesiveness without requiring organic solvents
2Ease of manufacture
If water is used as dispersion medium in silicone emulsion, then application cost is reduced, but curability deteriorates due to high latent heat of evaporation
Solution Approach 1:
The invention extracts and removes water from the curing process by using a two-stage approach: first applying the water-based silicone emulsion containing crosslinking agents, then separately applying a crosslinking catalyst solution. The actual crosslinking reaction occurs after water evaporation, eliminating the need to evaporate large amounts of water during curing and significantly reducing cure time while maintaining the cost advantages of water-based formulation
Solution Approach 2:
The silicone emulsion is prepared in advance with crosslinking agents (such as organohydrogenpolysiloxane) already incorporated into the water-based formulation. This preliminary incorporation of crosslinking components allows the system to proceed directly to crosslinking after application, without requiring extensive drying time, thereby reducing the overall cure time while maintaining low application costs
3Ease of manufacture
If water-based emulsion is used for silicone coating, then expensive application apparatus is not necessary, but film thickness uniformity deteriorates
Solution Approach 1:
The silicone emulsion is pre-formulated with optimal viscosity and rheological properties by selecting specific base polymers and additives. This preliminary optimization of the formulation ensures that the emulsion can be applied with simple equipment while still achieving uniform film thickness, as the pre-adjusted flow characteristics compensate for the lack of sophisticated application apparatus
Solution Approach 2:
The viscosity and surface tension parameters of the water-based emulsion are carefully adjusted through formulation optimization. By controlling these physical parameters, the emulsion achieves optimal flow and leveling properties that enable uniform film formation even when applied with cost-effective, simple equipment, thereby maintaining manufacturing precision without requiring expensive application apparatus
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 excellent adhesiveness to plastic film substrates and maintains suitable release properties, making it suitable for delamination films and reducing the need for expensive application apparatuses.
Implementation Method 1
the water-soluble silane coupling agent (I) has (i) one or more groups selected from among a succinic anhydride group and an ureido group
Implementation Method 2
an addition reaction-curable silicone emulsion composition comprising a water-soluble silane coupling agent (I), an organopolysiloxane (II) having at least two alkenyl groups in one molecule thereof, an organohydrogenpolysiloxane (III) having at least two hydrogen atoms directly bonded to a Si atom
Data Source
AI summary
The present invention is an addition reaction-curable silicone emulsion composition containing a water-soluble silane coupling agent (I) and an organopolysiloxane (II) having at least two alkenyl groups in one molecule thereof, where the water-soluble silane coupling agent (I) has at least one group selected from among a succinic anhydride group, a quaternary ammonium group, and a ureido group, and 1 part by mass or more of the water-soluble silane coupling agent (I) is contained relative to 100 parts by mass of the organopolysiloxane (II). This provides: a silicone emulsion composition that gives a cured film adhering well to plastic film substrates regardless of the type, while having suitable release properties regarding adhesives; and a delamination film made by forming a cured film of the silicone emulsion composition.