Siliceous Substrate Coating Process for Scrubbing Durability

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Solution Overview

Problem

Existing automotive coatings fail to provide sustained water repellency and durability on siliceous substrates, especially after scrubbing, as they lack effective interaction between components that enhance contact angles and friction reduction.

Innovation Solution

A process involving a first composition of at least partially hydrolyzed amine-reactive organosilane followed by a second composition of amino-functional silane or cyclic azasilane and condensation-curable polyorganosiloxane, forming a thin layer on siliceous substrates that improves contact angles and friction properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single coating composition is applied to provide water repellency and gloss, then the initial contact angle is improved, but the durability after scrubbing and repeated washing cycles deteriorates

Engineering Contradiction:

Improvedurability after scrubbingVSAvoidcoating process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The coating system is divided into two separate compositions applied in sequence: a first composition containing amine-reactive organosilane compound that forms a base layer, and a second composition containing amino-functional silane or cyclic azasilane with condensation-curable polyorganosiloxane that forms a top layer. This segmentation allows each composition to be optimized for specific functions - the first for adhesion and durability, the second for water repellency and gloss - thereby resolving the contradiction between durability and coating complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite coating system where the first and second compositions work together synergistically. The amine-reactive organosilane in the first composition reacts with amino-functional groups in the second composition to form a crosslinked network structure. This composite approach combines the durability benefits of the first composition with the water repellency and gloss of the second composition, achieving both improved reliability and functional performance.

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional automotive coatings are used to improve water repellency, then the contact angle is increased, but the friction reduction property after scrubbing deteriorates

Engineering Contradiction:

Improvefriction reduction after scrubbingVSAvoidwater spotting and staining

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical parameters of the coating system by incorporating specific amino-functional groups (primary, secondary, or tertiary amines) and cyclic azasilane structures. These chemical parameter changes enable the formation of a crosslinked network that maintains low coefficient of friction even after scrubbing, while the hydrophobic groups provide water repellency. This resolves the contradiction by adjusting molecular structure to achieve both friction reduction and water spot resistance.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a thick coating layer is applied to enhance durability, then the protection against weather and contaminants is improved, but the uniformity of water repellency and gloss deteriorates

Engineering Contradiction:

Improveprotection against weather and contaminantsVSAvoiduniformity of water repellency

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

By segmenting the coating into two applied layers with distinct functions, the invention achieves uniform water repellency and gloss on the surface while maintaining durability through the crosslinked network formed by the interaction of the two compositions. The first composition provides a uniform base layer for adhesion, while the second composition provides a uniform top layer for water repellency, preventing the uniformity issues that would arise from a single thick layer.

Inventive Principle:

Principle #1Segmentation

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 process achieves high receding contact angles and low coefficients of friction even after scrubbing, providing a durable and water-repellent coating that maintains performance through repeated washing cycles.

Implementation Method 1

The first composition includes an amine-reactive organosilane compound that is at least partially hydrolyzed

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

The second coating composition includes at least one of an amino-functional silane or cyclic azasilane and a condensation-curable polyorganosiloxane

Methodology Applied

Scientific EffectCondensation: Condensation

Data Source

PatentUS20230406760A1Process for making a coated article

Publication Date: 2023.12.21 3M INNOVATIVE PROPERTIES CO

AI summary

The process includes applying a first composition on at least the portion of a siliceous substrate and subsequently applying a second composition on at least a portion of the first composition. The first composition includes an amine-reactive organosilane compound that is at least partially hydrolyzed. The second coating composition includes at least one of an amino-functional silane or cyclic azasilane and a condensation-curable polyorganosiloxane having divalent units represented by formula (I). The use of the first composition to improve the durability of the second composition, a kit including the first composition and the second composition, and a coated article made by the process are also described.