Copolymers for Flexible Substrate Coatings Without Hot Embossing Tack
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Solution Overview
Problem
Existing binders for flexible substrates, such as leather and imitation leathers, face challenges in embossing at high temperatures without becoming tacky or experiencing cuts, with inadequate mechanical properties and formaldehyde issues in crosslinking processes.
Innovation Solution
Development of copolymers through specific copolymerization of ethylenically unsaturated monocarboxylic and dicarboxylic acids, along with other monomers, which are then used in aqueous dispersions for coating, allowing for improved embossability at temperatures above 90°C without tackiness and formaldehyde-free processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If existing binders are used for coating flexible substrates, then the substrates can be coated, but the substrates become tacky and experience cuts during embossing at high temperatures above 90°C
Solution Approach 1:
The patent modifies the chemical composition parameters of the binder by incorporating specific compounds (carboxylic acids, amides, esters) in controlled amounts to change the thermal properties of the coating, enabling it to resist tack at embossing temperatures above 90°C while maintaining proper adhesion and flexibility
Solution Approach 2:
The invention creates a composite binder system combining multiple monomer types (acrylates, carboxylic acids, amides, esters) with specific functional groups that work synergistically to provide both high-temperature tack resistance and proper embossing performance, forming a multi-component polymer architecture
2Strength
If crosslinking processes are used to improve mechanical properties, then the coating strength increases, but formaldehyde is released which is harmful
Solution Approach 1:
The patent eliminates formaldehyde as a crosslinking agent and replaces it with alternative crosslinking mechanisms using compounds like methylolacrylamide or carboxylic acids that can form crosslinks without releasing harmful formaldehyde, thereby converting the harmful crosslinking method into a beneficial formaldehyde-free crosslinking system that maintains coating strength
Solution Approach 2:
The invention extracts and removes formaldehyde from the crosslinking process entirely, replacing the traditional formaldehyde-based crosslinking mechanism with alternative crosslinking agents and methods that achieve the same mechanical property enhancement without the harmful byproduct
3Force
If the finish has high tack at room temperature, then the coating adheres well, but the embossing tools stick at high temperatures
Solution Approach 1:
The patent designs the binder with dynamic thermal response characteristics, where the coating's adhesive properties are optimized for room temperature application but automatically reduce tack at embossing temperatures through the thermal behavior of the incorporated carboxylic acid and amide groups, creating a temperature-dependent adhesion profile
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 copolymers enable flexible substrates to be readily embossed at high temperatures without sticking or cutting, with enhanced mechanical properties and a formaldehyde-free process, resulting in high-quality, soft, and flexible coated substrates suitable for various applications.
Implementation Method 1
copolymers prepared by copolymerization of (a) a total of from 3.5 to 20% by weight of at least one polymerizable acid selected from (a1) ethylenically unsaturated C3-C10-monocarboxylic acids and (a2) ethylenically unsaturated C4-C10-dicarboxylic acids or their anhydrides
Implementation Method 2
aqueous dispersions of the copolymers according to the invention for coating flexible substrates, in particular leather and imitation leathers
Implementation Method 3
embossing can be effected as quickly as possible at temperatures above 90° C. or even better above 100° C. without the embossing tools sticking
Data Source
AI summary
Copolymers prepared by copolymerization of(a) a total of from 3.5 to 20% by weight of at least one polymerizable acid selected from(a1) ethylenically unsaturated C3-C10-monocarboxylic acid and(a2) ethylenically unsaturated C4-C10-dicarboxylic acid or their anhydrides,(b) from 4 to 10% by weight of at least one compound of the general formula I the sum of (a) and (b) being in the range from 7.5 to 24% by weight,(c) from 60 to 92.5% by weight of at least one compound of the general formula II(d) from 0 to 0.5% by weight of at least one compound of the general formula III(e) from 0 to 10% by weight of (meth)acrylonitrile,(f) from 0 to 10% by weight of at least one conjugated diolefin,(g) from 0 to 10% by weight of at least one vinylaromatic compound of the general formula IVthe variables being defined as follows:R1 and R2 are identical or different and are selected from hydrogen and C1-C10-alkyl,R3 and R4 are identical or different and are selected from hydrogen, C1-C20-alkyl, phenyl, or R3 and R4 together are C2-C10-alkylene, substituted or unsubstituted,R5 is selected from C1-C20-alkyl and phenyl,R6, R7, R8, R9, R10 and R11 are identical or different and are selected from hydrogen and C1-C10-alkyl,x is an integer in the range from 0 to 12,y is selected from 0 and 1, x being chosen to be not equal to 0 when y is 1,k is an integer in the range from 0 to 3,it being possible for the copolymers to be completely or partly neutralized with alkali or ammonium anddata in % by weight being based in each case on the total copolymer.