Aqueous Dispersion Adhesive for Low-Temperature Heat Sealing

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Solution Overview

Problem

Conventional heat sealing methods require longer times and higher temperatures, which can be inefficient for certain substrates and adherends, and often result in adhesion issues such as blocking between laminates.

Innovation Solution

An aqueous dispersion containing ethylene-unsaturated carboxylic acid copolymer, polymer with acrylic acid ester units, and ethylene-vinyl acetate copolymer, which forms composite particles that provide excellent adhesive strength and anti-blocking properties, even with short heat sealing times and low temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional heat sealing methods are used, then substrates can be bonded, but heat sealing time is long and temperature is high

Engineering Contradiction:
Improveheat sealing speedVSAvoidheat sealing temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive layer by incorporating specific polymers (ethylene-unsaturated carboxylic acid copolymer with 10-25 mass% unsaturated carboxylic acid content, and ethylene-vinyl acetate copolymer with 5-50 mass% vinyl acetate content) to enable heat sealing at lower temperatures and shorter times while maintaining bonding performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite adhesive system combining multiple polymer components (ethylene-unsaturated carboxylic acid copolymer, ethylene-vinyl acetate copolymer, and optionally acrylic polymer) with specific content ratios to achieve both low-temperature heat sealing capability and high bonding strength

Inventive Principle:
Principle #40Composite materials

2Strength

If conventional adhesive layers are used, then substrates can be bonded, but adhesive strength is insufficient

Engineering Contradiction:
Improveadhesive strengthVSAvoidheat sealing time
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent optimizes the molecular composition parameters of the adhesive by controlling the content of functional groups and polymer types to achieve rapid adhesion development within 3 seconds at 150°C, balancing bonding strength and processing speed

Inventive Principle:
Principle #35Parameter changes

3Strength

If conventional heat seal materials are used, then bonding can be achieved, but blocking occurs between laminates

Engineering Contradiction:
Improveadhesive strengthVSAvoidblocking between laminates
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality control by forming an adhesive layer with specific thickness (1-10 μm) and controlled composition that provides sufficient bonding strength at the interface while preventing excessive adhesion between laminate surfaces, thereby eliminating blocking

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent adjusts the chemical composition parameters of the adhesive layer, specifically controlling the content of ethylene-vinyl acetate copolymer (5-50 mass% vinyl acetate) and ethylene-unsaturated carboxylic acid copolymer to achieve optimal balance between adhesive strength and anti-blocking properties

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 aqueous dispersion and resulting laminate exhibit strong adhesive strength and prevent blocking, making them suitable for various industrial applications with improved productivity and reduced energy consumption.

Implementation Method 1

the resin component contains ethylene-unsaturated carboxylic acid copolymer (A), polymer having an acrylic acid ester unit as a polymerization unit (B), and ethylene-vinyl acetate copolymer (C); and contains composite particles (D) having the ethylene-unsaturated carboxylic acid copolymer (A) and the polymer having an acrylic acid ester unit as a polymerization unit (B) and composite particles (E) having the ethylene-unsaturated carboxylic acid copolymer (A) and the ethylene-vinyl acetate copolymer (C)

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

a substrate such as a plastic film, vapor deposition film, metal foil, paper, and nonwoven fabric is bonded (that is, heat sealed) by heat and pressure

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3578601B1Aqueous dispersion and laminate
Publication Date: 2023.10.25 MITSUI CHEMICALS INC
  • EP3578601B1 patent drawingFigure 1

AI summary

An aqueous dispersion contains a resin component and water, wherein the resin component contains composite particles (D) having the ethylene-unsaturated carboxylic acid copolymer (A) and the polymer having an acrylic acid ester unit as a polymerization unit (B), and composite particles (E) having the ethylene-unsaturated carboxylic acid copolymer (A) and the ethylene-vinyl acetate copolymer (C).