Multilayer Packaging Structure with Water-Soluble Adhesive Layer
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Solution Overview
Problem
Current multilayer structures for plastic packaging face challenges in achieving both high humidity interlayer adhesiveness and peelability during separation, which are essential for effective recycling, particularly due to the high melting points of materials like polyethylene terephthalate and chlorine resins.
Innovation Solution
A multilayer structure comprising a substrate layer with a thermoplastic resin, a polyolefin layer, and a water-soluble layer containing a hydroxyl group-containing resin and alkali metal ions, with a density difference between layers to enhance peelability and oxygen barrier properties, allowing for efficient separation and recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a water-soluble layer is used to enable separation of different packaging materials, then peelability during separation is improved, but interlayer adhesiveness under high humidity deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the solubility characteristics and chemical composition of the water-soluble layer. By adjusting parameters such as the type of hydroxyl group-containing resin, molecular weight, and concentration, the layer achieves optimal balance between adhesion and solubility. This allows the layer to maintain strong bonding under high humidity while still dissolving effectively during the separation process.
Solution Approach 2:
The patent employs composite materials by combining multiple components in the water-soluble layer, including hydroxyl group-containing resins, plasticizers, and other additives. This composite approach enables the layer to exhibit both adequate adhesiveness for packaging application and sufficient solubility for separation, resolving the contradiction between these opposing requirements.
2Strength
If high melting point materials like polyethylene terephthalate are used to enhance mechanical properties, then strength is improved, but recyclability deteriorates due to difficulty in mixing with other materials
Solution Approach 1:
The patent applies segmentation by dividing the packaging structure into distinct layers with different materials, each serving specific functions. The water-soluble layer acts as a separable interface that allows high-strength materials like polyethylene terephthalate to be used in one layer while enabling separation from other layers during recycling. This segmentation enables selective recycling of different materials without requiring them to be mixed during manufacturing.
Solution Approach 2:
The water-soluble layer serves as an intermediary between different packaging materials with different melting points and properties. It provides a common interface that facilitates bonding between dissimilar materials during packaging while enabling their separation during recycling. This intermediary layer resolves the incompatibility issue between high melting point materials and recyclability by allowing independent processing of each material after use.
3Reliability
If polyvinylidene chloride is used to enhance gas barrier properties, then oxygen barrier property is improved, but recyclability deteriorates due to influences on processing facilities and quality deterioration
Solution Approach 1:
The patent segments the packaging structure into separate layers, placing polyvinylidene chloride in a specific layer that can be independently separated. The water-soluble layer acts as a barrier to mixing during packaging while enabling clean separation during recycling. This allows polyvinylidene chloride to provide excellent oxygen barrier properties in its designated layer without compromising the recyclability of other materials in the packaging structure.
Solution Approach 2:
The water-soluble layer functions as an intermediary that isolates polyvinylidene chloride from direct contact with other packaging materials during the packaging function, preventing quality deterioration. During recycling, the same intermediary layer facilitates clean separation, allowing polyvinylidene chloride to be recovered or disposed of independently without affecting processing facilities or the quality of recycled materials from other layers.
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 proposed multilayer structure exhibits superior interlayer adhesiveness under high humidity and peelability during separation, ensuring effective recycling of materials by maintaining the quality of contents and facilitating the separation of different types of plastics.
Implementation Method 1
dissolving a part or all of the water-soluble layer (A) by bringing the multilayer structure into contact with water
Implementation Method 2
sedimenting the layer structure (X) and floating the layer structure (Y) in the water
Implementation Method 3
a density difference (X-Y) between the layer structure (X) and the layer structure (Y) is 0.2 g/cm³ or more
Implementation Method 4
superior in interlayer adhesiveness under high humidity
Implementation Method 5
superior in an oxygen barrier property
Data Source
AI summary
Present disclosure provides a multilayer structure including a layer structure (X) and a layer structure (Y) which are laminated via a water-soluble layer (A).