Organopolysiloxane Coating Composition for Fast Cure and Weather Resistance
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Solution Overview
Problem
Existing organopolysiloxane coatings have slow cure rates and inferior crack resistance, flex resistance, chemical resistance, stain resistance, and weather resistance when combined with organic resins, and require complex synthesis equipment for composite formation.
Innovation Solution
A coating composition comprising polyols, polyisocyanate, and hydroxyl group-containing organopolysiloxane, which can be mixed at room temperature, resulting in a cured film with enhanced chemical resistance, stain resistance, and weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an organopolysiloxane is used as a coating material, then heat resistance and weather resistance are improved, but the cure rate becomes slow and crack resistance deteriorates
Solution Approach 1:
The patent combines organopolysiloxane with organic resin components (polyol and polyisocyanate) to create a composite coating system. This composite approach allows the coating to exhibit both the heat and weather resistance of organopolysiloxane and the fast cure rate and crack resistance of organic resin crosslinking networks.
Solution Approach 2:
The patent modifies the chemical composition parameters by introducing specific ratios of polyol, polyisocyanate, and organopolysiloxane. By controlling these compositional parameters, the coating achieves optimized cure characteristics while maintaining the protective properties of organopolysiloxane.
2Productivity
If an organopolysiloxane is mixed with an organic resin to improve curability and crack resistance, then the cure rate and crack resistance are improved, but chemical resistance and stain resistance deteriorate
Solution Approach 1:
The patent creates a composite system where organopolysiloxane molecules are integrated within the organic resin crosslinked network. This composite structure allows the coating to simultaneously achieve the mechanical properties (crack resistance) and protective properties (chemical and stain resistance) of both material types.
Solution Approach 2:
The patent achieves different local properties within the coating film: the organopolysiloxane domains provide chemical and stain resistance, while the organic resin crosslinked network provides mechanical strength and crack resistance. This local differentiation of functions resolves the contradiction between mechanical and chemical properties.
3Reliability
If a composite of organic resin and organosilane is synthesized to achieve desired properties, then performance is improved, but manufacturing complexity increases due to required synthesis equipment
Solution Approach 1:
The patent uses pre-synthesized organopolysiloxane as a starting material, eliminating the need for on-site synthesis equipment. The organopolysiloxane is prepared in advance with the desired molecular structure and properties, and then simply mixed with the organic resin components to form the final coating composition.
Solution Approach 2:
The patent extracts the complex synthesis step from the coating formulation process. Instead of requiring synthesis equipment to create the composite in situ, the patent separates the synthesis of organopolysiloxane as a preliminary step, leaving only simple mixing operations for the final coating application.
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 provides a cured film with improved chemical resistance, stain resistance, and weather resistance, suitable for various coated articles without the need for complex synthesis equipment.
Implementation Method 1
a polyol, a polyisocyanate and a given hydroxyl group-containing organopolysiloxane are mixed together in given proportions is curable at room temperature
Implementation Method 2
by formulating an organopolysiloxane having alkoxy groups on the ends with a curing catalyst and applying external energy such as heat energy, the terminal alkoxy groups mutually react, forming a strong siloxane network
Data Source
AI summary
Provided is a coating composition that contains (A) a polyol such as an acrylic polyol, (B) a compound having two or more isocyanate groups per molecule, and (C) a hydroxyl group-containing organopolysiloxane represented by formula (I) (SiO4/2)a(R1SiO3/2)b(R12SiO2/2)c(R13SiO1/2)d(R2O1/2)e(R3O1/2)f (I) (R1 is a monovalent saturated hydrocarbon group, etc., R2 is a methyl group, etc., R3 is a group represented by formula (II), a, b, c, and d are numbers that satisfy 0 ≤ a < 1, 0 < b ≤ 1, 0 ≤ c ≤ 0.5, 0 ≤ d < 1, and a+b+c+d = 1, and e and f are numbers that satisfy 0 ≤ e ≤ 1, 0 < f < 4, and 0 < e + f < 4.) (R4 is a monovalent saturated hydrocarbon group, etc., R5 is a hydrogen atom, etc., X is a divalent hydrocarbon group, n is a number of 0-400, and * represents a bond with an oxygen atom.), the ratio of the number of isocyanate groups in component (B) to the sum of the number of hydroxyl groups in components (A) and (C) being 0.8-1.4.