Polysiloxane Composite Coating for Oxidative Decomposition Resistance
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Solution Overview
Problem
Photocatalyst-containing water-based curable coating compositions face challenges in forming durable, crack-resistant, and weather-resistant films due to oxidative decomposition effects, with poor compatibility between inorganic and organic components leading to reduced long-term durability and weather resistance.
Innovation Solution
A two-component water-based coating composition using a polysiloxane segment as a base, combined with a polymer segment having a neutralized acid group and fine particles of photocatalytic oxide, and a curing agent to form a composite resin that is chemically bonded via silicon-oxygen bonds, enhancing durability and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic resins or inorganic-organic composite resins are used as binder resin to resist oxidative decomposition, then durability is improved, but compatibility between inorganic and organic components is poor and crosslinking reaction is limited
Solution Approach 1:
The invention uses a composite resin containing both inorganic polysiloxane segments and organic polymer segments with carboxyl groups. The polysiloxane provides oxidation resistance while the organic polymer enhances compatibility and crosslinking. The composite structure allows both components to work synergistically, resolving the contradiction between durability and compositional stability.
Solution Approach 2:
The invention modifies the chemical parameters of the binder resin by introducing carboxyl groups into the organic polymer segment. This parameter change enables chemical interaction between the organic and inorganic components through crosslinking reactions, improving compatibility while maintaining the oxidation resistance provided by polysiloxane segments.
2Reliability
If inorganic resins are used as binder resin to achieve solvent resistance and water resistance, then weather resistance is improved, but crosslinking reaction proceeds only among polysiloxane portion
Solution Approach 1:
The composite resin combines polysiloxane segments for weather resistance with organic polymer segments containing carboxyl groups for extended crosslinking capability. This composite structure enables crosslinking reactions to occur both within the polysiloxane portion and within the organic polymer portion, creating a more durable three-dimensional network that maintains weather resistance while improving long-term durability.
3Ease of manufacture
If common organic resins are used as binder resin, then ease of manufacture is improved, but organic matter decomposes due to oxidative decomposition effect
Solution Approach 1:
The invention creates a composite resin where polysiloxane segments provide oxidation resistance to protect against photocatalytic decomposition, while organic polymer segments maintain ease of manufacture characteristics. The composite structure allows the system to retain processing advantages of organic resins while gaining the oxidation stability of inorganic polysiloxane, resolving the contradiction between ease of manufacture and durability.
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 solution achieves a cured coating film with improved durability against oxidative decomposition, excellent crack resistance, and enhanced weather and stain resistance, suitable for various applications including exterior constructions.
Implementation Method 1
a polysiloxane segment (B) forming a composite resin (AB) by chemically bonding with the polymer segment (A)
Implementation Method 2
the polysiloxane segment (C) forming a composite resin (ABC) by coupling with the polymer segment (A) and the polysiloxane segment (B) via silicon-oxygen bonds
Implementation Method 3
the oxidative decomposition effect or effect of rendering a superhydrophilic surface, caused by the irradiation of sunlight
Implementation Method 4
a photocatalytic material is attracting attention in various fields typified by the field of exterior construction as a material having a self-cleaning function
Data Source
AI summary
The present invention provides a photocatalyst-containing water-based curable coating composition capable of forming a cured coating film having an excellent durability against the oxidative decomposition effect caused by the photocatalyst, and an excellent crack resistance, as well as excellent weather resistance and stain resistance; and a method for producing the coating composition. Specifically, the present invention provides a photocatalyst-containing water-based curable coating composition comprising: one of a water-based dispersion (X1) or a water-based dispersion (X2), which includes a water-based medium, a polymer segment (A) having a neutralized acid group, a polysiloxane segment (B) forming a composite resin (AB) by chemically bonding with the polymer segment (A), a polysiloxane segment (C) derived from an alkyltrialkoxysilane condensate (c) with an alkyl group of 1 to 3 carbon atoms, the polysiloxane segment (C) forming a composite resin (ABC) by coupling with the polymer segment (A) and the polysiloxane segment (B) via silicon-oxygen bonds, and fine particles of a photocatalytic oxide (D), wherein the water-based dispersion (X1) is formed by dispersing or dissolving the composite resin (ABC) and dispersing the fine particles of a photocatalytic oxide (D) in the water-based medium, the water-based dispersion (X2) is formed by dispersing resin particles in a water-based medium, the resin particles formed by the encapsulation of the fine particles of a photocatalytic oxide (D) within the composite resin (ABC); and a curing agent (E) for curing the composite resin (ABC), and a method for producing the coating composition.