Repulpable Paper Fiber Insulation for Recyclable Mailers

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Solution Overview

Problem

Insulated boxes are typically made from disparate materials, making recycling impossible due to the combination of different components, which limits their recyclability.

Innovation Solution

A method and system for producing repulpable insulation materials and containers using repulpable insulation material, where fibrous paper or cellulose material is mixed with recyclable binder fibers, formed into a batt, and combined with recyclable paper layers to create a recyclable insulation material that can be used in shipping containers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If insulated boxes are made from disparate materials to achieve thermal insulation and protection functions, then the insulation performance and protective functions are improved, but the recyclability deteriorates because different materials cannot be recycled together

Engineering Contradiction:
Improveinsulation performanceVSAvoidrecyclability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies homogeneity by using only repulpable materials (paper, cardboard, fiberboard) for both the insulation layer and the container structure. This ensures that all components are made from the same material family, enabling them to be recycled together in a single stream without requiring separation of different material types. The insulation material is formed from repulpable fibers that can be processed with the container materials through conventional recycling operations.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The patent changes the material parameter from using disparate materials (plastics, foams, metals) to using repulpable materials throughout. This parameter change enables the insulation material to be integrated with container materials in the recycling process, transforming a multi-material system into a single-material system that can be handled by existing recycling infrastructure.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If traditional insulation materials are used to maintain thermal properties, then thermal insulation is achieved, but the ability to recycle through single-stream processing is lost due to material contamination

Engineering Contradiction:
Improvethermal insulationVSAvoidrecycling efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The patent ensures homogeneity of material composition by using repulpable materials for both insulation and container structure. This eliminates material contamination issues that would arise from combining different material types in recycling streams, thereby enabling efficient single-stream recycling processing without requiring complex sorting or separation operations.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The patent embraces a disposable design philosophy where the insulation material and container are made from inexpensive, easily recyclable repulpable materials. The focus is on creating a simple, single-use product that can be efficiently recycled after use, rather than designing for durability or reuse, thereby optimizing for recycling efficiency rather than product longevity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 insulation material achieves over 85% repulpability, allowing for single-stream recycling without material separation, and maintains thermal insulation properties while being adaptable for various shipping needs.

Implementation Method 1

mixing paper reinforcement fibers with a thermoplastic binder fiber and melting the thermoplastic binder fiber to bind the paper reinforcement fibers together

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

The insulation material achieves over 85% repulpability, allowing for single-stream recycling without material separation, and maintains thermal insulation properties

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4321681B1Method of making an insulation material and an insulated mailer
Publication Date: 2025.12.24 PRATT RETAIL SPECIALTIES LLC
  • EP4321681B1 patent drawingFigure 1
  • EP4321681B1 patent drawingFigure 2
  • EP4321681B1 patent drawingFigure 3

AI summary

A method and system for producing an insulated mailer and an insulated box having an insulative paper fiber pad substructure with a density of less than about 10 pounds per cubic foot. The insulative paper fiber pad has entangled reinforcement fibers. A method of forming an insulative paper fiber pad using recycling-compatible or water soluble adhesive and paper layers is provided.