Thermoforming Permeable Infusion Packets via Heated Mould Contact

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional thermoforming processes are unsuitable for manufacturing three-dimensional infusion packets due to the non-thermoformability and porosity of infusion packet materials like paper, which leads to inefficient heat transfer and impractical air pressure formation, limiting the ability to create a variety of shapes.

Innovation Solution

A thermoforming process involving a gas and liquid permeable layer of thermoplastic material with low heat capacity, where the material is brought into contact with a heated mould to raise its temperature for thermoforming, allowing the material to conform to a mould shape without prior heating, and then a particulate product is deposited and sealed to form infusion packets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional thermoforming processes are used, then three-dimensional shapes can be formed, but infusion packet material cannot be thermoformed due to its non-thermoformability and porosity

Engineering Contradiction:

Improvethree-dimensional shapeVSAvoidthermoformability

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

The invention changes the thermal parameters of the process by eliminating pre-heating and instead using direct contact with a heated mould. The mould temperature is maintained above the thermoforming temperature of the thermoplastic material, allowing the material to heat up rapidly during pressing due to its low heat capacity and thinness.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of heating the material first and then forming it (conventional approach), the invention inverts the sequence by bringing the cold material into contact with a pre-heated mould, allowing the material to heat up during the forming process itself.

Inventive Principle:

Principle #13The other way round (Inversion)

2Shape

If air pressure is used for thermoforming, then material can be formed, but air pressure equalises quickly due to porosity making the approach impractical

Engineering Contradiction:

Improveformed shapeVSAvoidair pressure retention

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The invention replaces the pneumatic system (air pressure) with a direct mechanical pressing system. A mould is pressed into contact with the thermoplastic material, using mechanical force to deform the material during the brief period it remains thermoformable after contact with the heated mould.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Shape

If material is pressed into contact with mould, then shape can be formed, but limited shapes can be created due to fragility of porous and thin material

Engineering Contradiction:

Improvethree-dimensional shapeVSAvoidshape variety

Core Design Contradiction:

ShapeVSAdaptability or versatility

Solution Approach 1:

The invention performs preliminary heating of the mould before contact with the material. This ensures the material heats up rapidly and achieves adequate deformability during the pressing operation, reducing fragility and enabling more complex shape formation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the temperature parameter dynamically during the process - the mould is maintained at a temperature above the thermoforming temperature, creating a temperature gradient that allows the material to become sufficiently pliable during contact to form complex shapes.

Inventive Principle:

Principle #35Parameter changes

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 process effectively generates a range of three-dimensional shapes, including tetrahedral and hemispherical forms, that are gas and liquid permeable, suitable for infusion packets, overcoming the limitations of conventional methods by leveraging the low heat capacity and porosity of the material.

Implementation Method 1

pressing the mould into contact with the layer of thermoplastic material, the contact between mould and thermoplastic material causing heat to transfer from the mould to the thermoplastic material and raising the temperature of the thermoplastic material to a thermoformable temperature

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

such pressing thereby causing thermoforming of the thermoplastic material to conform to the shape of the mould

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP2663447B1Process for thermoforming infusion packets

Publication Date: 2015.05.06 UNILEVER PLC

Figure 1~2

AI summary

Provided is a process for thermoforming a gas and liquid permeable layer (10) of thermoplastic material having an average thickness of less than 1.0 mm, the process comprising the steps of bringing the layer of thermoplastic material, at a temperature below that required for thermoforming, into contact with a mould (16) at a temperature above that of a thermoforming temperature of the thermoplastic material; pressing the mould into contact with the layer of thermoplastic material, the contact between mould and thermoplastic material causing heat to transfer from the mould to the thermoplastic material and raising the temperature of the thermoplastic material to a thermoformable temperature; such pressing thereby causing thermoforming of the thermoplastic material to conform to the shape of the mould.