Microwave Heating for Multilayer Substrate Expansion

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Solution Overview

Problem

Conventional heating methods, such as thermal temperature sources, are inefficient in activating heat-expandable adhesives and coatings at production speeds, leading to limited thermal energy transfer and lower expansion efficiency, which slows down the manufacturing process of thermally-insulated packaging containers.

Innovation Solution

The use of an industrial microwave heater to rapidly heat the heat-expandable adhesives or coatings applied to sheet materials during the manufacturing process, leveraging microwave energy to quickly absorb and expand the materials, thereby enhancing insulation and rigidity in packaging substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional thermal heating methods are used to activate heat-expandable adhesives and coatings, then the activation process can be completed, but the production speed is reduced and thermal energy transfer efficiency is limited

Engineering Contradiction:

Improveproduction speedVSAvoidthermal energy transfer efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent replaces conventional thermal heating methods with microwave heating technology. The microwave heater generates electromagnetic radiation that directly excites the heat-expandable adhesive or coating material, causing rapid molecular vibration and heat generation within the material itself. This substitution of heating mechanism enables significantly faster activation and expansion of the adhesive/coating, thereby increasing production speed while improving thermal energy transfer efficiency through direct dielectric heating rather than conventional conduction or convection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If conventional heating methods are used to expand heat-expandable adhesives and coatings, then expansion occurs, but the expansion efficiency is reduced and manufacturing time increases

Engineering Contradiction:

Improvemanufacturing speedVSAvoidactivation time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent utilizes the phase transition properties of microwave energy to heat and expand the adhesive or coating material. The microwave radiation induces dielectric heating that rapidly increases the temperature of the material, triggering the phase transition from a compressed state to an expanded state. This rapid phase transition occurs much faster than with conventional heating methods, significantly reducing activation time and increasing manufacturing speed.

Inventive Principle:

Principle #36Phase transitions

3Strength

If heat-expandable adhesives and coatings are applied to sheet materials, then insulation and rigidity are provided, but the activation process is slow with conventional heating

Engineering Contradiction:

Improvemechanical strengthVSAvoidactivation speed

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The patent replaces conventional thermal heating with microwave heating to activate the heat-expandable adhesive or coating. The microwave heater generates electromagnetic radiation that directly excites the material, causing rapid molecular vibration and heat generation. This enables the adhesive/coating to expand and provide mechanical strength and insulation properties much faster, thereby increasing activation speed while maintaining the desired strength characteristics.

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

This method significantly increases the efficiency of activating heat-expandable adhesives, allowing for faster production speeds and improved thermal insulation and mechanical strength in packaging materials, while maintaining the ability to keep contents hot or cold.

Implementation Method 1

heating up sheet or roll web material and other substrates for containers with a microwave heater during the manufacturing process, causing a heat-expandable adhesive or coating applied to the sheet material or substrates to rapidly expand

Methodology Applied

Scientific EffectMicrowave heating: Dielectric Heating

Implementation Method 2

Such expandable adhesives and coatings expand upon being heated over a certain temperature

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2611588B1Method for manufacturing a multilayer substrate for packaging

Publication Date: 2019.12.04 LBP MANUFACTURING INC

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AI summary

A method for manufacturing a multilayer sheet material includes, at some point during passage of the sheet material through a machine system, heating the multilayer sheet material with a microwave heater to expand a heat-expandable adhesive or coating applied to or within the multilayer sheet material. Various types of multilayer substrates may be created depending on the steps used and the application of the heat-expandable adhesive or coating. Additionally, a monolayer sheet may be coated with a pattern of heat-expandable coating before passage of the monolayer sheet through the machine system that heats the monolayer sheet to expand the heat-expandable coating applied to the monolayer sheet. The microwave heater used by the machine system may be a planar type and have a plurality of microwave guides surrounding a space through which the sheet material(s) pass. The microwave heater may be operable at multiple frequencies.