Curtain Wall Primer Composition for Humidity-Stable Adhesion
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Solution Overview
Problem
Existing primer compositions face challenges in achieving good adhesion to difficultly bondable adherends such as acrylic electrophoretic painted aluminum and fluororesin-painted aluminum, with issues of durability and stability in humid environments, and require a short working life for coating operations.
Innovation Solution
A primer composition is formulated by mixing an organopolysiloxane resin with a specific titanium compound and solvent in a predetermined ratio, eliminating the need for high activity titanates, ensuring adhesion to various adherends and improving durability and working life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high activity titanate is used to improve adhesion to painted metal surfaces, then adhesion performance is improved, but the primer composition becomes unstable in humid environments and working life is shortened
Solution Approach 1:
The patent changes the chemical parameters of the titanate compound by specifying exact molecular structures (formulae 1-4) with particular alkoxy groups and chelating ligands. This parameter optimization allows the titanate to provide strong adhesion while maintaining stability in humid conditions, resolving the contradiction between adhesion strength and environmental stability.
Solution Approach 2:
The primer composition uses a composite system combining organopolysiloxane resin with specifically formulated titanate compounds. This composite approach leverages the complementary properties of both components: the organopolysiloxane provides base adhesion and stability, while the optimized titanate enhances adhesion to painted surfaces without sacrificing stability.
2Strength
If high activity titanate is used to improve adhesion, then adhesion performance is improved, but working life for coating operation is reduced
Solution Approach 1:
The patent optimizes the molecular parameters of the titanate compound to control its reactivity. By selecting specific alkoxy groups (such as tert-butoxy, 2-ethylhexyloxy) and chelating ligands, the patent achieves a balance where the titanate remains stable enough during storage and application (providing adequate working life) but still forms strong adhesive bonds with painted metal surfaces.
3Reliability
If silane base primers are used to achieve heat resistance and weather resistance, then durability is improved, but adhesion to organic adherends such as acrylic electrophoretic painted aluminum is insufficient
Solution Approach 1:
The patent creates a composite primer system that combines organopolysiloxane resin (providing heat and weather resistance) with specifically formulated titanate compounds (providing adhesion to organic and painted surfaces). This composite approach allows simultaneous achievement of durability and adhesion performance that neither component could provide alone.
Solution Approach 2:
The primer composition is designed to provide multiple functions simultaneously: adhesion to metal substrates, adhesion to painted surfaces, heat resistance, and weather resistance. The combination of organopolysiloxane and optimized titanate compounds enables this multi-functional performance across different adherend types including acrylic electrophoretic painted aluminum.
4Strength
If acrylic primers are used to improve adhesion to acrylic painted surfaces, then adhesion is improved, but heat resistance and weather resistance are reduced compared to silicone base primers
Solution Approach 1:
The patent formulates a composite primer using organopolysiloxane resin as the base (providing superior heat and weather resistance) combined with optimized titanate compounds (providing adhesion to acrylic and other organic painted surfaces). This composite system achieves both adhesion performance and environmental resistance that pure acrylic primers cannot provide.
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 primer composition provides enhanced adhesion to difficultly bondable adherends, with improved durability and a working life of at least 20 minutes in humid conditions, suitable for bonding silicone rubber layers to metal and painted metal surfaces.
Implementation Method 1
a primer composition comprising (A) an organosiloxane polymer of three-dimensional network structure comprising R3SiO1/2 units and SiO4/2 units, a molar ratio of R3SiO1/2 units to SiO4/2 units being 0.6 to 1.2
Implementation Method 2
an organosiloxane polymer of three-dimensional network structure comprising R3SiO1/2 units and SiO4/2 units
Implementation Method 3
an organosiloxane polymer of three-dimensional network structure comprising R3SiO1/2 units and SiO4/2 units
Data Source
AI summary
Provided are a primer composition that can adhere well to a variety of adherends and ensures a long workable time together with excellent durability, and a curtain wall unit. A primer composition comprising: (A) 100 parts by mass of an organosiloxane polymer having a three-dimensional network structure comprising R3SiO1/2 units (R independently represents a C1-6 substituted or unsubstituted monovalent hydrocarbon group) and SiO4/2 units, the molar ratio of R3SiO1/2 units to SiO4/2 units being 0.6-1.2; (B) 300-1,000 parts by mass of a mixture of organo-oxy-group-containing titanium compounds containing 75 mol % or more of an organo-oxy-group-containing titanium compound represented by formula (1)Ti(OR1)3(R2CH2COCHCOOCH2R2)1 (1)(R1 may be the same or different and are substituted or unsubstituted monovalent hydrocarbon groups, R2 may be the same or different and are hydrogen atoms and/or substituted or unsubstituted monovalent hydrocarbon groups); and (C) 1,000-8,000 parts by mass of a solvent.