Aqueous Coating Agent Composition for Rubber Adhesion
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Solution Overview
Problem
Conventional aqueous emulsion-type coating agents for rubber and plastic surfaces lack sufficient adhesiveness, abrasion resistance, and durability, and often require organic solvents, which pose safety and environmental concerns, while using organotin compounds as curing catalysts is restricted due to toxicity issues.
Innovation Solution
An aqueous coating agent composition comprising polydiorganosiloxane with blocked terminals, polyorganohydrogensiloxane, a zinc compound as a curing catalyst, an organic compound with amino groups, an adhesion improving component, and spherical particles, which forms a coating film with excellent adhesiveness and abrasion resistance without using organotin compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an organic solvent diluted coating agent is applied as an aqueous coating agent, then water can be used as dispersion medium, but it is impossible to sufficiently obtain durability, adhesiveness, or the like of a coating film
Solution Approach 1:
The patent changes the chemical composition parameters by using polydiorganosiloxane with specifically controlled viscosity (50-10,000,000 mPa·s) and terminal hydroxyl groups, combined with polyorganohydrogensiloxane with controlled Si-H bond content. This parameter optimization enables the aqueous coating agent to achieve sufficient adhesiveness and durability without organic solvents.
Solution Approach 2:
The patent creates a composite coating system by combining multiple components: polydiorganosiloxane (A), polyorganohydrogensiloxane (B), zinc compound curing catalyst (C), adhesion improving component (D), and optional spherical particles (E). This composite formulation achieves both environmental friendliness and coating performance.
2Reliability
If organotin compound is used as a curing catalyst, then coating film can be cured, but toxicity concerns lead to restrictions and regulations on its use
Solution Approach 1:
The patent extracts and removes the harmful organotin compound from the curing catalyst system, replacing it with a zinc compound (such as zinc stearate, zinc oxide, or zinc acetate). This extraction eliminates the toxicity issue while preserving the essential curing function through the silicon-hydrogen bond reaction.
Solution Approach 2:
The patent employs a zinc compound as a safer, more environmentally friendly alternative to organotin compounds. The zinc-based curing system provides sufficient curing capability without the long-term environmental persistence and toxicity associated with organotin compounds.
3Object-affected harmful factors
If conventional aqueous emulsion-type coating agents are used, then organic solvents are eliminated, but adhesiveness and abrasion resistance of coating film are insufficient
Solution Approach 1:
The patent optimizes the viscosity parameter of polydiorganosiloxane to a specific range (50-10,000,000 mPa·s) and controls the Si-H bond content in polyorganohydrogensiloxane (0.1-10 mmol/g). These parameter changes enable the aqueous emulsion to achieve both environmental friendliness and sufficient coating strength.
Solution Approach 2:
The patent formulates a composite aqueous coating agent combining polydiorganosiloxane with terminal hydroxyl groups and polyorganohydrogensiloxane with Si-H bonds. This composite system undergoes condensation reaction to form a cross-linked network structure, providing both environmental compatibility and mechanical strength.
4Strength
If dealcoholized condensation type silicone-based emulsion is mixed with chlorinated polyolefin, then adhesiveness and abrasion resistance are improved, but satisfactory performance is still not obtained
Solution Approach 1:
The patent changes the fundamental composition parameters by using polydiorganosiloxane with terminal hydroxyl groups and polyorganohydrogensiloxane with Si-H bonds in an aqueous emulsion system. This parameter optimization achieves high adhesiveness and abrasion resistance without requiring complex multi-component mixtures like dealcoholized condensation type emulsions combined with chlorinated polyolefin.
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 a coating film with superior adhesiveness, slipperiness, and abrasion resistance on rubber and plastic surfaces, particularly on EPDM materials, while being safe and environmentally friendly, and can be used in various applications without the toxicity concerns associated with organotin compounds.
Implementation Method 1
a zinc compound as a curing catalyst
Implementation Method 2
the silane component with water to prevent emulsification
Implementation Method 3
an organic compound and/or polyorganosiloxane having at least one of a primary amino group and a secondary amino group
Data Source
AI summary
There is provided an aqueous coating agent composition that does not contain an organotin compound and forms a coating film having good slipperiness and having excellent adhesiveness (adhesion) and abrasion resistance. The aqueous coating agent composition contains: (A) polydiorganosiloxane having both terminals blocked with hydroxyl groups, the polydiorganosiloxane having a viscosity of 50 to 100,000,000 mPa·s (at 25° C.); (B) polyorganohydrogensiloxane having at least three hydrogen atoms in one molecule; (C) a zinc compound as a curing catalyst; (D) an organic compound and/or polyorganosiloxane having at least one of a primary amino group and a secondary amino group; (E) an adhesion improving component; and (F) spherical particles.