Biodegradable Coated Paper With Crack-Resistant Film Formation

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Solution Overview

Problem

Conventional coated papers using biodegradable resins like poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) suffer from coating defects such as cracks and pinholes, and the biodegradation rate is slow, reducing the environmental benefits.

Innovation Solution

A coated paper design incorporating a coating layer with poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and an adhesive, with a specific solid content weight ratio of 99.9/0.1 to 60.0/40.0, applied on a paper base material, optionally with a seal layer to enhance adhesion and prevent soaking, using biodegradable adhesives and binders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an aqueous dispersion liquid of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is applied to form a coating layer, then the coated paper achieves biodegradability and environmental friendliness, but the coating layer develops defects such as cracks and pinholes

Engineering Contradiction:
ImprovebiodegradabilityVSAvoidcoating uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent combines poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with specific additives including plasticizers, nucleating agents, and processing aids to create a composite coating system. This composite approach maintains the biodegradability of the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) while the additives prevent coating defects through improved film formation and reduced stress cracking.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes multiple parameters including the molecular weight distribution of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), the concentration of additives in the aqueous dispersion liquid, drying temperature, and coating thickness. By carefully controlling these parameters, the coating forms uniformly without cracks or pinholes while preserving the biodegradable properties of the polymer.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is used as the coating resin, then the coated paper exhibits excellent degradation properties under aerobic and anaerobic conditions, but the biodegradation rate in the natural environment such as the ocean is slow

Engineering Contradiction:
Improvedegradation propertyVSAvoidbiodegradation rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent introduces biodegradation promoters and enzyme catalysts as intermediary substances in the coating layer. These intermediaries facilitate the breakdown of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) by natural microorganisms in the environment, accelerating the biodegradation rate while maintaining the polymer's inherent ability to decompose under both aerobic and anaerobic conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the molecular structure and physical properties of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) by controlling its molecular weight, crystallinity, and copolymer composition. These parameter changes optimize the balance between mechanical properties for coating formation and biodegradation rate for environmental decomposition.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the coating layer is made with high resin content to ensure functional properties, then the coated paper achieves water resistance, oil resistance, and heat-sealing property, but the coating layer becomes prone to cracks and pinholes

Engineering Contradiction:
Improvefunctional propertiesVSAvoidcoating defect reduction
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent creates a composite coating system combining poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with flexible plasticizers, nucleating agents, and processing aids. This composite formulation allows the coating layer to achieve sufficient resin content for functional properties (water resistance, oil resistance, heat-sealing) while the additives prevent crack and pinhole formation by improving film continuity and reducing internal stress.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent replaces purely mechanical coating application with a chemically optimized coating system where the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and additives work together to form a defect-free film. The chemical composition and molecular interactions between components enable uniform film formation without relying solely on mechanical coating parameters.

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 coated paper achieves a uniform coating layer with reduced defects, ensuring biodegradability and maintaining functional properties like heat-sealing, water-resistance, and oil-resistance, while rapidly decomposing in the environment.

Implementation Method 1

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

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the coating layer is a water-resistant layer

Methodology Applied
Scientific EffectHydrophobicity: Hydrophobe

Implementation Method 3

the coating layer is an oil-resistant layer

Methodology Applied
Scientific EffectOleophobicity: Hydrophobe

Implementation Method 4

the coating layer is a heat-sealing layer

Methodology Applied
Scientific EffectThermal bonding: Heating

Implementation Method 5

a poly(3-hydroxybutyrate)-based resin is a microbially produced thermoplastic plastic that uses plant material and has excellent degradation property under aerobic and anaerobic conditions

Methodology Applied
Scientific EffectBiodegradation: Decomposition (biological)

Data Source

PatentUS12351985B2Coated paper
Publication Date: 2025.07.08 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.