Laser Marking Composition With Triazine Crosslinking for Readable Codes

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Solution Overview

Problem

Existing laser marking compositions using bismuth-based agents and (meth)acrylic resins suffer from heat-induced carbonization, gas generation, and blistering, leading to readability issues in printing one-dimensional or two-dimensional codes, particularly due to the decolorization of bismuth and poor heat resistance.

Innovation Solution

A laser marking composition comprising a (meth)acrylic resin, a bismuth-containing compound, and a crosslinking agent with a triazine-ring skeleton, where the proportion of structural units derived from methacrylic acid and methacrylic acid alkyl ester is less than 45% by mass, along with optional urethane resin and filler, to enhance heat resistance and readability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a bismuth-based laser color developing agent is used, then color development and visibility are improved, but heat resistance deteriorates due to decolorization at elevated temperatures

Engineering Contradiction:

ImprovevisibilityVSAvoidheat resistance

Core Design Contradiction:

Measurement precisionVSTemperature

Solution Approach 1:

The patent uses a composite resin system combining (meth)acrylic resin with polyurethane resin and cellulose derivative, where the polyurethane resin contains hydroxy groups that coordinate with bismuth to prevent decolorization, while the cellulose derivative provides thermal stability. This composite approach maintains visibility while improving heat resistance.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent specifies precise compositional parameters: the polyurethane resin must contain 5-50 mass% hydroxy groups, and the cellulose derivative must be a lower acyl group-substituted or lower alkyl group-substituted type with specific substitution degrees. These parameter controls optimize the balance between color development and heat resistance.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If (meth)acrylic resin is used, then ease of manufacture is improved, but gas generation and blistering occur during laser marking

Engineering Contradiction:

Improveease of manufactureVSAvoidgas generation

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent introduces polyurethane resin as an intermediary component that contains 5-50 mass% hydroxy groups. This intermediary coordinates with bismuth atoms to form stable complexes, preventing the heat-induced decolorization and reducing gas generation during laser marking, while still allowing the (meth)acrylic resin to provide ease of manufacture.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite system where (meth)acrylic resin is combined with polyurethane resin (containing hydroxy groups) and cellulose derivative. This composite material suppresses gas generation and blistering during laser marking while maintaining the manufacturability benefits of (meth)acrylic resin.

Inventive Principle:

Principle #40Composite materials

3Temperature

If urethane resin with high hydroxy group content is used to prevent decolorization, then heat resistance is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveheat resistanceVSAvoidmanufacturing complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent specifies precise parameter ranges to balance heat resistance and manufacturing complexity: polyurethane resin must contain 5-50 mass% hydroxy groups (optimized to prevent decolorization without excessive complexity), and the cellulose derivative must have specific substitution patterns. These controlled parameters simplify manufacturing while achieving the desired heat resistance.

Inventive Principle:

Principle #35Parameter changes

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 suppresses gas generation and blistering, improving the heat resistance and readability of printed codes by reducing tertiary carbon content and stabilizing bismuth coloration through triazine-ring skeleton crosslinking.

Implementation Method 1

bismuth-based laser color developing agents such as bismuth oxide generate bismuth through a reduction reaction caused by a laser

Methodology Applied

Scientific EffectReduction reaction: Reduction

Implementation Method 2

During reduction, heat is generated, which causes carbonization of the resin or generation of gas

Methodology Applied

Scientific EffectHeat generation: Heating

Implementation Method 3

Since the (meth)acrylic resin contained in the laser marking composition contains a hydroxy group or a carboxy group as a crosslinking point, decolorization of bismuth due to the (meth)acrylic resin may occur

Methodology Applied

Scientific EffectCoordination:

Data Source

PatentUS20260103614A1Laser marking composition, resin film, and layered body

Publication Date: 2026.04.16 NIPPON CARBIDE KOGYO KK

AI summary

A laser marking composition includes at least one (meth)acrylic resin, a bismuth-containing compound, and a crosslinking agent having a triazine-ring skeleton, in which a total of proportions of structural units derived from methacrylic acid and structural units derived from a methacrylic acid alkyl ester with respect to all structural units of the (meth)acrylic resin is less than 45% by mass.