Polycarbonate Urethane Acrylate Coating for Scratch Resistance

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Solution Overview

Problem

Existing active energy ray-curable resin compositions lack excellent substrate followability, adhesion, car-wash scratching resistance, hardness, and weather resistance.

Innovation Solution

A composition containing urethane (meth)acrylate with a polycarbonate skeleton and multiple polymerizable unsaturated groups, combined with specific polymerizable unsaturated compounds and a photopolymerization initiator, within specific molecular weight ranges and ratios, to form a cured coating film with improved properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional active energy ray-curable resin compositions are used, then curing speed is fast and no heating is required, but substrate followability, adhesion, scratching resistance, hardness, and weather resistance are insufficient

Engineering Contradiction:
Improvecuring speedVSAvoidcoating film performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent uses a composite resin composition containing multiple components: (A) urethane (meth)acrylate with polycarbonate skeleton and 3+ unsaturated groups, (B) urethane (meth)acrylate with specific molecular weight, (C) polymerizable unsaturated compounds with specific structures, and (D) photopolymerization initiator. This composite approach allows the coating to achieve both fast curing and superior mechanical properties through synergistic effects of different components.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters including molecular weight ranges of components (A) and (B), the structure and concentration of compound (C), and the type and amount of photopolymerization initiator (D). By precisely controlling these parameters, the coating achieves optimal balance between curing speed and final film properties.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If thermosetting coating materials or lacquer are used, then substrate followability and adhesion may be improved, but productivity is poor due to required cooling and drying time

Engineering Contradiction:
Improvecoating film performanceVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces thermal curing mechanisms (heating and drying required for thermosetting coatings) with photopolymerization initiated by UV light or other active energy rays. This substitution eliminates the need for thermal processing time, enabling instant curing upon irradiation and dramatically improving productivity while maintaining coating quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 a coating film with enhanced substrate followability, adhesion, car-wash scratching resistance, hardness, and weather resistance, as evidenced by the specific molecular weight between crosslinks and glass transition temperature ranges.

Implementation Method 1

a photopolymerization initiator; wherein the active energy ray-curable coating composition is irradiated with an active energy ray to cure the coating composition

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS12060494B2Actinic-ray-curable coating composition, cured coating film, coated article, and method for forming coating film
Publication Date: 2024.08.13 KANSAI PAINT CO LTD

AI summary

An active energy ray-curable coating composition, includes the following components (A), (B), (C), and (D): (A) urethane (meth)acrylate having a polycarbonate skeleton and three or more polymerizable unsaturated groups in one molecule and having a weight average molecular weight in a range of 10,000 to 40,000; (B) urethane (meth)acrylate having a weight average molecular weight in a range of 1,000 or more and less than 10,000; (C) at least one compound selected from the group consisting of (c1) to (c3); and (D) a photopolymerization initiator.