Localized Heat Sealable Coating on Water Repellent Paper

Solution Overview

Problem

Current methods for making paper cups require a thick polyethylene layer for heat sealability and water repellency, which increases material usage and reduces recyclability, while also relying on fossil fuel-derived materials.

Innovation Solution

A process where a heat sealable coating layer is applied only on selected areas of a water repellent substrate, such as paper or paper board, using a water borne or solvent borne formulation with a surface tension similar to the water repellent layer, typically below 30 dynes per cm, to enhance adhesion and reduce material usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thick polyethylene layer is applied on paper substrate for heat sealability and water repellency, then the barrier properties and heat sealability are improved, but the material usage increases and recyclability decreases

Engineering Contradiction:

Improvebarrier properties and heat sealabilityVSAvoidcoating weight

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies heat sealable coating only on selected areas of the paper substrate where heat sealing is actually needed (such as sealing flaps and joining areas), rather than coating the entire surface. This localized application maintains the necessary heat sealability and water repellency at critical points while significantly reducing the total quantity of polyethylene material used.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The coating process is segmented into selective application zones. The substrate is divided into areas requiring heat sealable coating and areas where only water repellent coating is applied. This segmentation allows optimization of material usage by applying the thicker heat sealable layer only where functionally necessary.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a thick polyethylene layer is applied for full coverage, then the water repellency and pinhole-free barrier are achieved, but the fossil fuel-derived material usage increases

Engineering Contradiction:

Improvepinhole-free barrierVSAvoidfossil fuel-derived materials

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies heat sealable coating only on selected areas of the paper substrate where heat sealing is actually needed (such as sealing flaps and joining areas), rather than coating the entire surface. This localized application maintains the necessary heat sealability and water repellency at critical points while significantly reducing the total quantity of polyethylene material used.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If a thick coating layer is applied from liquid phase, then better coverage is obtained, but the coating weight and material consumption increase

Engineering Contradiction:

Improvecoverage qualityVSAvoidcoating weight

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent applies heat sealable coating only on selected areas of the paper substrate where heat sealing is actually needed (such as sealing flaps and joining areas), rather than coating the entire surface. This localized application maintains the necessary heat sealability and water repellency at critical points while significantly reducing the total quantity of polyethylene material used.

Inventive Principle:

Principle #3Local quality

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

This approach reduces the amount of heat sealable coating material needed, improves recyclability, and enhances the sustainability profile of the paper cups by minimizing fossil fuel-derived materials and optimizing material application.

Implementation Method 1

a heat sealable coating layer is applied on selected areas of a water repellent substrate... wherein the surface tension of the heat sealable coating layer is similar to the surface tension of the water repellent coating layer

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

the heat sealable coating layer comprises a surfactant or a solvent... wherein the surfactant or the solvent is selected to reduce the surface tension of the heat sealable coating layer below 30 dynes per cm

Methodology Applied

Scientific EffectSurface tension reduction: Surfactant

Implementation Method 3

a water repellent substrate... wherein the water repellent substrate comprises a water repellent coating layer

Methodology Applied

Scientific EffectHydrophobicity: Hydrophobe

Data Source

PatentEP3491189B1Paper with water repellent and partially heat sealing properties

Publication Date: 2025.06.04 SOLENIS BELGIUM BV

Figure 1

AI summary

The present invention relates to a process for making a heat sealable substrate starting from a water repellent substrate. In particular, the present invention relates to a process for making water repellent paper cups. In particular, the present invention discloses a process for applying one or more heat sealable strips on a water repellent substrate, for example paper or paper board. Further, the present invention also relates to a heat sealable substrate obtained by said process for making paper cups.