Biodegradable Polyester–Polyvinyl Alcohol Adhesive for Laminate Bonding

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Solution Overview

Problem

Conventional biodegradable laminates exhibit insufficient adhesive strength between polyvinyl alcohol resin and biodegradable resin layers.

Innovation Solution

An adhesive resin composition comprising a biodegradable polyester resin and polyvinyl alcohol resin, with a specific parameter (Y/X) ranging from 0.30 to 0.99, where X is the mass of polyvinyl alcohol resin in a film and Y is the mass extracted in hot water, forming a co-continuous structure that enhances adhesive strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional adhesive compositions are used in biodegradable laminates, then the laminate structure can be formed, but the adhesive strength between polyvinyl alcohol resin layer and biodegradable resin layer is insufficient

Engineering Contradiction:
Improveadhesive strengthVSAvoidbonding reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive layer by incorporating both polyvinyl alcohol resin and biodegradable polyester resin in specific proportions. This parameter change enables the adhesive layer to simultaneously achieve strong bonding to both polyvinyl alcohol resin layers and biodegradable resin layers, resolving the insufficient adhesive strength problem while maintaining biodegradability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite adhesive material combining polyvinyl alcohol resin and biodegradable polyester resin. This composite approach allows the adhesive layer to exhibit dual compatibility - bonding effectively to both polar polyvinyl alcohol surfaces and non-polar biodegradable resin surfaces - thereby achieving reliable bonding strength that conventional single-material adhesives cannot provide.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If biodegradable resins are used to prevent environmental pollution, then environmental friendliness is improved, but adhesive strength in laminate structures deteriorates

Engineering Contradiction:
Improveenvironmental pollutionVSAvoidadhesive strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The biodegradable polyester resin in the adhesive layer serves multiple functions: it provides bonding capability to biodegradable resin layers, maintains adhesive performance in moisture environments, and ensures overall laminate integrity. This multi-functionality allows the adhesive to achieve reliable strength while maintaining the biodegradable and environmentally friendly characteristics of the entire laminate structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The biodegradable polyester resin acts as an intermediary component in the adhesive layer, mediating between the polar polyvinyl alcohol resin layers and non-polar biodegradable resin layers. This intermediary material bridges the compatibility gap between different resin types, enabling effective bonding throughout the laminate while preserving biodegradability and environmental friendliness.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4636034A1Adhesive resin composition
Publication Date: 2025.10.22 KURARAY CO LTD
  • EP4636034A1 patent drawingFigure 1~2
  • EP4636034A1 patent drawingFigure 3
  • EP4636034A1 patent drawing

AI summary

The present invention relates to an adhesive resin composition including a biodegradable polyester resin (A) and a polyvinyl alcohol resin (B). In the adhesive resin composition, Expression (1): 0.30 < Y/X < 0.99 (1) [in which X represents the mass of the polyvinyl alcohol resin (B) included in a film including the adhesive resin composition and having a thickness of 300 µm, and Y represents the mass of the polyvinyl alcohol resin (B) extracted in hot water in immersion of the film in pure water at 80°C for 1 hour] is satisfied.