Silane Adducts for Scratch-Resistant Coatings

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing scratch-resistant clear coats face challenges with low solids content due to high molecular weights of silane-functional crosslinkers, leading to inadequate flexibility and surface defects from crystallization, especially at curing temperatures below 100 °C.

Innovation Solution

The use of low molecular weight adducts of isocyanatoalkyl-trialkoxysilanes and aliphatic branched diols or polyols, which are liquid at temperatures above 0 °C, forming coatings that are scratch-resistant, flexible, and maintain their properties over a wide temperature range, including below 100 °C.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high molecular weight silane-functional crosslinkers are used to achieve scratch resistance, then crosslinking density and scratch resistance are improved, but solids content decreases and flexibility deteriorates

Engineering Contradiction:

Improvescratch resistanceVSAvoidsolids content

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent segments the crosslinking function by using low molecular weight silane compounds (solid content >80%) that react with isocyanates to form crosslinks. This segmentation allows high solids content while maintaining scratch resistance through efficient crosslinking at lower molecular weights.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the molecular weight parameter of silane compounds from high to low (<310 g/mol), which simultaneously increases solids content and maintains scratch resistance. It also optimizes the NCO:Si ratio parameter (0.4:1 to 2:1) to achieve optimal crosslinking density with low molecular weight silanes.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If low molecular weight silane adducts are used to increase solids content, then flexibility is improved, but tendency to crystallize increases causing surface defects

Engineering Contradiction:

Improvesolids contentVSAvoidcrystallization tendency

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state parameter by selecting silane compounds that remain liquid at application temperatures (>0°C). It optimizes molecular weight (62-310 g/mol) and structural parameters to prevent crystallization while maintaining high solids content and flexibility.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses low molecular weight silane compounds that are liquid at room temperature, avoiding the need for high-temperature curing that would be required for crystalline adducts. This enables application at lower temperatures without surface defects.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Strength

If adducts from isocyanatopropyltrialkoxysilanes and low molecular weight diols are used to achieve high solids content, then scratch resistance is improved, but flexibility becomes inadequate and crystallization occurs

Engineering Contradiction:

Improvescratch resistanceVSAvoidflexibility

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent changes the molecular weight parameter of silane compounds to 62-310 g/mol and optimizes the NCO:Si ratio to achieve adequate flexibility while maintaining high scratch resistance. It selects silanes that remain liquid at application temperatures to prevent crystallization-related flexibility loss.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite crosslinking system combining low molecular weight silanes with isocyanate groups that react to form flexible urethane linkages while maintaining high crosslink density for scratch resistance. The resulting coating combines flexibility and hardness.

Inventive Principle:

Principle #40Composite materials

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 coatings exhibit high scratch resistance, excellent leveling, and gloss, with a solids content greater than 80% by weight, and are curable at temperatures between 20 to 100 °C, ensuring flexibility and mechanical stress resistance.

Implementation Method 1

The NCO groups of the compounds of the formula (I) react with the OH groups of the compounds of the formula (II) to form -NH-CO-O groups

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

The adducts lead to surprisingly scratch-resistant coatings

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

silane crosslinking

Methodology Applied

Scientific EffectCondensation: Condensation

Data Source

PatentEP2641925B1Adducts from isocyanatoalkyl trialkoxysilanes and aliphatic, alkyl-branched diols or polyols

Publication Date: 2017.02.01 EVONIK OPERATIONS GMBH

AI summary

Adduct obtained by reacting isocyanato-alkyl trialkoxysilane compounds (I) with diol compounds (II), is claimed. Adduct obtained by reacting isocyanato-alkyl trialkoxysilane compounds of formula (OCN-(A1)-Si(A2) 3) (I) with diol compounds of formula (HO-(R)-OH) (II), is claimed. A1 : 1-4C alkylene; A2 : OCH 3, ethoxy, propoxy or butoxy; and R : branched 2-20C alkylene or 2-20C cycloalkylene (both optionally substituted by OH). Independent claims are also included for: (1) a coating agent comprising (A) the above adduct, and optionally (B) at least one binder component, (C) up to 3 wt.% at least one catalyst, (D) auxiliaries and additives, and (E) an organic solvent; and (2) a metal coating composition and a coating compositions for glass-, plastic- or wood coatings, comprising the above coating agent.