Cardboard-Plastic Tray Lamination Without Vent Holes or Adhesives
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Solution Overview
Problem
Existing methods for producing cardboard-plastic composite trays require ventilation holes to remove air during bonding, which complicates the process and increases material waste, and often use adhesives that hinder recyclability.
Innovation Solution
A method involving pre-forming a plastic film to match the tray shape, folding an unfolded cardboard blank onto the film without overlaps, and laminating them together without adhesives, ensuring air escapes naturally during folding, allowing for rapid, cost-effective, and recyclable tray production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ventilation holes are added to the cardboard box to remove air during bonding, then air can escape during the bonding process, but the device complexity and material waste increase
Solution Approach 1:
The invention extracts the harmful element (air bubbles) by creating a one-way valve system that allows air to escape during bonding but prevents plastic material from leaking out. This resolves the contradiction by enabling air removal without compromising bonding integrity or increasing overall device complexity.
Solution Approach 2:
The invention applies local quality by creating ventilation channels with specific geometric features (inclined surfaces, rough surfaces) only in specific locations where air needs to escape. The one-way valve mechanism is localized to particular areas of the mold, allowing air removal functionality without complicating the entire mold structure.
2Reliability
If ventilation holes are added to the cardboard box to remove air during bonding, then air can escape during the bonding process, but material waste increases
Solution Approach 1:
The invention extracts the harmful element (air bubbles) by creating a one-way valve system that allows air to escape during bonding but prevents plastic material from leaking out. This resolves the contradiction by enabling air removal without compromising bonding integrity or increasing overall device complexity.
Solution Approach 2:
The invention uses porous or permeable structures in the ventilation channels that allow air passage while blocking plastic material. The rough surfaces and inclined surfaces create a filter-like effect that permits gas escape but retains liquid plastic, eliminating material waste.
3Strength
If adhesives are used to join cardboard blank to plastic film, then bonding strength is improved, but recyclability deteriorates
Solution Approach 1:
The invention applies self-service by using the plastic material itself to create the bonding connection between cardboard and plastic film, eliminating the need for separate adhesive substances. The plastic forms mechanical interlocks and molecular bonds with the cardboard through direct contact and heating, providing both bonding strength and recyclability.
Solution Approach 2:
The invention creates a composite structure where plastic and cardboard are directly bonded through thermal and mechanical processes. The resulting composite material maintains the properties of both components while achieving strong adhesion without additional adhesive layers, ensuring recyclability.
4Shape
If the cardboard blank is completely folded before bonding, then the tray shape is well-defined, but air trapping occurs during bonding
Solution Approach 1:
The invention applies preliminary action by pre-forming the plastic material into a tray shape before bonding to the cardboard. This allows the plastic to conform to the desired shape while remaining flexible enough to allow air escape during the bonding process, resolving the contradiction between shape definition and air trapping.
Solution Approach 2:
The invention uses dynamics by allowing the plastic material to change state during bonding - transitioning from a flexible, air-permeable state during the bonding process to a rigid, shape-defining state after bonding. The plastic film is heated to become more pliable during bonding, then cools to maintain the defined tray shape.
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 simplifies and speeds up the production process, reduces material waste, and enhances recyclability by eliminating the need for ventilation holes and adhesives, resulting in a sealed, gap-free tray with improved environmental compatibility.
Implementation Method 1
the plastic film is pre-formed (8) by means of a punch tool (36) into a shell shape (14) which preferably already corresponds at least substantially to the desired inner surface (44) of the cardboard-plastic composite shell (10)
Implementation Method 2
the plastic film (12) is subsequently joined (68) to the cardboard blank (16) following the pre-forming step (66)
Implementation Method 3
the cardboard blank (16) is folded onto the pre-formed plastic film (12) by means of a folding mechanism (22)
Data Source
Figure 1~2
Figure 3~5
Figure 6~7b
AI summary
The invention relates to a method for producing a cardboard-plastic composite shell (10), in particular a MAP cardboard-plastic composite shell for food, having at least the steps (66, 68, 82, 88) of: - providing a plastic film (12), - pre-deforming the plastic film (12) in order to form a shell shape (14), - providing a cardboard blank (16), and - connecting the cardboard blank (16) to a plastic film (12) which has already been pre-deformed in order to form the cardboard-plastic composite shell (10). According to the invention, the provided cardboard blank (16) is not folded or is not completely folded immediately prior to the process of connecting the pre-deformed plastic film (12).