Fluoroalkylsilane Coating Composition Storage Stability

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Solution Overview

Problem

Existing easy-to-clean coatings based on fluoroorgano-functional silanes and siloxanes have short storage stability, low abrasion resistance, and lose their oleophobic effect quickly, with a need for improved weathering stability and durability.

Innovation Solution

A coating composition comprising hydrolyzable fluoroalkylsilane, HCl, water, isopropanol, and a solvent or diluent, with a silane:water molar ratio of 1:4.5 to 1:9, undergoes controlled hydrolysis and condensation, providing a stable, abrasion-resistant, and weathering-stable easy-to-clean coating for inorganic surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing fluoroorgano-functional silane coating systems are used, then easy-clean properties are achieved, but storage stability is short and abrasion resistance is low

Engineering Contradiction:
Improvestorage stabilityVSAvoidcoating durability
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical composition parameters by introducing specific fluoroalkylsilane compounds with controlled hydrolyzable groups (chlorine, methoxy, ethoxy, isopropoxy, or n-propoxy) and adjusting the silane-to-water molar ratio to 1:4.5 to 1:9. This parameter optimization enables the coating to maintain storage stability of at least one year while achieving excellent abrasion resistance and weathering stability.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If fluoroalkylsilane coatings are applied, then oleophobic effect is provided, but the effect is lost after short time

Engineering Contradiction:
Improveeasy-clean propertiesVSAvoidoleophobic effect duration
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent creates a composite coating system combining fluoroalkylsilane components with specific solvents (isopropanol and other solvents/diluents) and controlled water content. This composite formulation maintains the oleophobic and hydrophobic properties while significantly extending the duration of the easy-clean effect through optimized molecular structure and composition.

Inventive Principle:
Principle #40Composite materials

3Reliability

If weathering stability is improved, then outdoor application suitability increases, but formulation complexity increases

Engineering Contradiction:
Improveweathering stabilityVSAvoidformulation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by selectively introducing fluoroalkyl groups with specific chain lengths (n=3-9) and terminal CF3 groups at targeted positions in the molecular structure. This localized modification of the silane molecule provides enhanced weathering stability and outdoor durability without requiring complex multi-component formulations or additional processing steps.

Inventive Principle:
Principle #3Local quality

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 outstanding storage stability, excellent abrasion resistance, and high weathering and chemical resistance, maintaining easy-clean properties for over a year, suitable for outdoor applications on smooth inorganic surfaces.

Implementation Method 1

a storage-stable, easy-to-clean coating composition based on components a) at least one hydrolyzable fluoroalkylsilane of the formula (I)... c) water... undergoes controlled hydrolysis and condensation

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

a storage-stable, easy-to-clean coating composition based on components a) at least one hydrolyzable fluoroalkylsilane of the formula (I)... undergoes controlled hydrolysis and condensation

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentUS7666257B2Storage-stable coating composition for abrasion-resistantly and weathering-stably providing smooth inorganic surfaces with easy-to-clean properties
Publication Date: 2010.02.23 EVONIK OPERATIONS GMBH

AI summary

The present invention relates to a special coating composition based on components a) at least one hydrolysable fluoroalkylsilane of the formula (I) CF3(CF2)n(CH2)2Si(CH3)yX3-y, in which X is a group from the series chlorine, methoxy, ethoxy, isopropoxy, and n-propoxy and n is a number from the series 3, 4, 5, 6, 7, 8, and 9, and y is 0 or 1, b) HCl, c) water, d) isopropanol, and e) at least one further solvent and/or diluent from the series of the alcohols, glycols, glycol ethers, ethers, esters, ketones, and aliphatic and aromatic hydrocarbons, wherein the silane component (a):water molar ratio of 1:4.5 to 1:9. The invention further relates to a process for preparing such a composition and also to its use for providing smooth, inorganic substrate surfaces with an abrasion-resistant and weathering-stable easy-to-clean coating.