Low-Temperature Coating Composition Using Alkylidene-1,3-dioxolan-2-one Crosslinkers
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Solution Overview
Problem
Current coating compositions based on polyurethanes for automotive painting and refinishing face challenges such as high reactivity leading to moisture sensitivity, discoloration issues, health risks from diisocyanates, and unsatisfactory reactivity of polymers with 1,3-dioxolan-2-one groups, which necessitate the development of alternative solutions that do not require polyisocyanates or melamine-formaldehyde resins.
Innovation Solution
Non-aqueous coating compositions containing polyamino groups and oligomeric/polymeric compounds with at least two alkylidene-1,3-dioxolan-2-one groups, specifically using monomers of formula (I) and different comonomers to enhance reactivity and eliminate the need for polyisocyanates and melamine-formaldehyde resins, while ensuring low inherent color and reversible thermal yellowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyhydric isocyanates are used in polyurethane coating compositions, then crosslinking reactivity is improved, but moisture sensitivity increases and health risks arise
Solution Approach 1:
The patent removes polyisocyanates and melamine-formaldehyde resins from the coating composition, extracting the harmful crosslinking agents while maintaining crosslinking functionality through an alternative mechanism using polymers with 1,3-dioxolan-2-one groups that cure under basic conditions without requiring these toxic substances
Solution Approach 2:
The patent employs a catalyst system based on readily available basic compounds (amines, metal oxides, hydroxides) that can be easily handled and disposed of, replacing the expensive and hazardous polyisocyanates while achieving comparable or superior crosslinking performance
2Object-affected harmful factors
If polymers with 1,3-dioxolan-2-one groups are used as crosslinking agents, then polyisocyanates can be eliminated, but reactivity is insufficient
Solution Approach 1:
The patent introduces basic compounds (amines, metal oxides, hydroxides) as intermediary catalysts that activate the 1,3-dioxolan-2-one groups, enabling them to react with hydroxyl-containing polymers at practical curing temperatures and times, thereby achieving sufficient crosslinking reactivity without polyisocyanates
Solution Approach 2:
The patent optimizes the molecular weight, hydroxyl value, and composition of the polymer components to enhance reactivity of the 1,3-dioxolan-2-one groups, adjusting physical and chemical parameters to achieve adequate crosslinking speed and extent under practical curing conditions
3Productivity
If conventional polyurethane crosslinking agents are used, then crosslinking speed is improved, but discoloration and yellowing occur
Solution Approach 1:
The patent converts the typically slow-reacting 1,3-dioxolan-2-one groups into beneficial low-yellowing crosslinking agents by using basic catalysts that accelerate their reactivity, thereby achieving both fast curing and excellent color stability that conventional polyisocyanate systems 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 coating compositions achieve sufficient crosslinking under common curing conditions, avoid ecological issues, and exhibit significantly lower inherent color with reversible thermal yellowing, meeting the requirements for automotive series painting and refinishing without the use of toxic compounds.
Implementation Method 1
polymerizable alkylidene-1,3-dioxolan-2-one monomers, their preparation, and their use in the production of the corresponding homo- or copolymers
Implementation Method 2
containing at least one polyamino group-containing compound (A) and at least one compound (B) with at least two alkylidene-1,3-dioxolan-2-one groups
Data Source
AI summary
The present invention relates to a non-aqueous coating material composition comprising at least one compound (A) having at least two amino groups and also at least one oligomeric and/or polymeric compound (B) having at least two alkylidene-1,3-dioxolan-2-one groups, characterized in that the compound (B) is obtainable using at least one monomer (B1) of the formula (I) where R1 and R2 independently of one another are hydrogen, C1-C6-alkyl, C1-C4-alkoxy-C1-C4-alkyl, C5-C6-cycloalkyl, phenyl or phenyl-C1-C4- alkyl; R3 is hydrogen, C1-C6-alkyl, C1-C4-alkoxy-C1-C4-alkyl, C5-C6- cycloalkyl, phenyl or phenyl-C1-C4-alkyl; R4 is hydrogen, C1-C4-alkyl, CH2COOR8, phenyl or phenyl-C1-C4-alkyl; R5 and R6 independently of one another are hydrogen or C1-C4-alkyl, or else one of the radicals R5 or R6 may be COOR8 or CH2COOR8; A is a chemical bond or C1-C4-alkanediyl; X is O or NR7; Z is a chemical bond, PO2, SO2 or C=O; Y is a chemical bond, CH2 or CHCH3; R7, if present, is C1-C6-alkyl; R8, if present, is hydrogen or C1-C6-alkyl; and at least two different comonomers (B2) und (B3), each different from the monomer (B1). Also subjects of the present invention are the coatings produced from these coating material compositions, and their use.