Biodegradable Coated Paper Composition to Prevent Cracks and Pinholes

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Solution Overview

Problem

Conventional coated papers using non-biodegradable resins face environmental degradation issues, and biodegradable alternatives like poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) suffer from coating defects such as cracks and pinholes.

Innovation Solution

A coated paper design incorporating a coating layer with poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and an adhesive, with a specific weight ratio, on a paper base material, optionally with a seal layer, to enhance adhesion and reduce defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If biodegradable plastic poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is used as coating material, then environmental degradability is improved, but coating defects such as cracks and pinholes occur

Engineering Contradiction:
Improveenvironmental degradationVSAvoidcoating quality
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The invention uses a composite coating system combining biodegradable polyester (P3HB3HH) with adhesive resins (polyvinyl alcohol, carboxymethyl cellulose, or starch) to create a coating layer that maintains both biodegradability and coating integrity. The adhesive components fill and seal potential defect areas while the biodegradable polyester provides environmental breakdown capability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention optimizes specific parameters including the weight ratio of biodegradable polyester to adhesive (99.9/0.1 to 60.0/40.0), coating amount (1.0 to 20.0 g/m²), and molecular weight of the polyester (50,000 to 500,000). These parameter adjustments ensure proper film formation while preventing coating defects.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional non-biodegradable resin is used for coating, then coating performance and durability are improved, but environmental load increases

Engineering Contradiction:
Improvecoating performanceVSAvoidenvironmental load
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention modifies the chemical composition parameters of the coating material by using biodegradable polyester with specific molecular weights (50,000 to 500,000) and controlled composition ratios, enabling environmental degradation while maintaining coating functionality through optimized formulation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite coating system that integrates biodegradable polyester with adhesive resins, combining the environmental benefits of biodegradability with the performance characteristics of conventional adhesives, achieving both reliability and reduced environmental impact.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If high coating amount is applied to reduce defects, then coating quality is improved, but material cost and processing load increase

Engineering Contradiction:
Improvecoating qualityVSAvoidcoating material consumption
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The invention optimizes the coating amount parameter to a specific range (1.0 to 20.0 g/m²) that achieves adequate coverage and defect prevention without excessive material consumption. This optimal parameter range balances coating quality with material efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The adhesive components (polyvinyl alcohol, carboxymethyl cellulose, or starch) act as intermediaries that enhance coating uniformity and fill potential defect areas, allowing effective coating at lower material amounts by improving distribution and reducing waste.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 coated paper achieves biodegradability with minimal coating defects, maintaining quality and functionality, suitable for various applications including heat-sealing, water-resistance, and oil-resistance.

Implementation Method 1

an aqueous dispersion liquid of biodegradable polyester that contains poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

excellent in film forming property and gives a resin coating film that is flexible, extends well, and resists bending

Methodology Applied
Scientific EffectFilm forming:

Implementation Method 3

a coating layer including poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and an adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4166716B1Coated paper
Publication Date: 2026.03.04 NIPPON PAPER IND CO LTD

AI summary

An object of the present invention is to provide a coated paper that includes a coating layer containing poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with few coating defects. As a solution, the present invention provides a coated paper including a coating layer containing poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and an adhesive, on at least one side of a paper substrate. A solid content weight ratio of the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) to the adhesive in the coating layer is 99.9/0.1 to 60.0/40.0.