Liquid Silicone Rubber Composition for Soft, Non-Tacky Textile Coatings
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Solution Overview
Problem
Current liquid silicone rubber (LSR) compositions used for textile coating result in a tacky and unsatisfactory film appearance, and increasing viscosity or crosslinking density to address this issue leads to difficulties in coating and increased stiffness of the treated textiles.
Innovation Solution
A liquid silicone rubber composition comprising a liquid polydiorganosiloxane with alkenyl radicals, an organohydrogenpolysiloxane, a reinforcing filler like silica, a polydiorganosiloxane-polyether copolymer, and a hydrosilylation catalyst, optimized to provide improved film appearance and physical properties such as softness and low-tackiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If viscosity and crosslinking density of liquid polydiorganosiloxane are increased to reduce tackiness and improve film appearance, then film appearance and tackiness are improved, but coating difficulty increases and textile stiffness increases
Solution Approach 1:
The invention changes the chemical composition parameters of the liquid silicone rubber by incorporating specific ratios of polyether-modified components (0.1-10 wt%) and adjusting crosslinking density through controlled organometallic catalyst amounts (0.01-5 wt%). This allows achieving non-tacky film appearance while maintaining coating processability and textile softness, resolving the contradiction between film quality and processing ease.
Solution Approach 2:
The invention creates a composite liquid silicone rubber system combining polydiorganosiloxane base polymer with polyether-modified segments and organometallic catalyst components. This composite structure provides synergistic effects where the polyether segments reduce tackiness and improve film appearance, while the controlled crosslinking system maintains coating ease and textile flexibility, simultaneously addressing multiple conflicting requirements.
2Object-generated harmful factors
If crosslinking density is increased to improve film appearance, then film appearance is improved, but elongation properties deteriorate
Solution Approach 1:
The invention optimizes the crosslinking density parameter within a specific range by controlling the amount of organometallic catalyst (0.01-5 wt%) and polyether-modified component (0.1-10 wt%). This controlled parameter adjustment achieves the right balance between film appearance quality and elongation properties, preventing excessive crosslinking that would harm elongation while still improving film appearance.
Solution Approach 2:
The invention introduces polyether-modified segments that create local flexible regions within the crosslinked silicone rubber matrix. These local soft segments maintain elongation capability even when the overall crosslinking density is increased for improved film appearance, allowing different parts of the material to have different properties - rigid crosslinked network for film quality and flexible polyether segments for elongation.
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 soft and non-tacky film with enhanced elongation properties, improving the coating process and physical characteristics of the treated textiles without the drawbacks of increased stiffness or coating difficulties.
Implementation Method 1
a liquid silicone rubber (LSR) composition useful for textile coating, which comprises: (A) 100 parts by weight of a liquid polydiorganosiloxane containing at least two alkenyl radicals in each molecule, (B) an organohydrogenpolysiloxane containing at least three silicon-bonded hydrogen atoms in each molecule
Data Source
AI summary
The present invention relates to a liquid silicone rubber composition useful for textile coating, in particular for textile coating by screen-printing. The LSR composition of the present invention shows better film appearance and better physical properties such as softness, low-tackiness, and elongation.