Tetramer Acid Polyester Adhesive for Retort-Resistant Packaging
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Solution Overview
Problem
Existing adhesives used in packaging materials fail to meet the increased demands for retorting resistance and content resistance, particularly in applications involving high-temperature treatments and strong-smelling products.
Innovation Solution
An adhesive comprising a polyol composition with a polyester polyol derived from a tetramer acid and a polyisocyanate composition, which provides enhanced retorting and content resistance due to its branch structure and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional polyol composition and polyisocyanate composition are used to form a two-component curable adhesive, then the adhesive can be obtained with basic bonding properties, but the adhesive lacks sufficient retorting resistance and content resistance under high-temperature and high-pressure conditions
Solution Approach 1:
The patent changes the chemical parameters of the polyol composition by introducing a polyester polyol with specific molecular structure (containing ether oxygen atoms and hydroxyl groups at specific positions) to improve retorting resistance. This involves modifying the chemical composition parameters rather than changing the overall adhesive formulation approach.
Solution Approach 2:
The patent creates a composite adhesive system by combining the specifically structured polyester polyol with polyisocyanate composition and other additives. The composite nature of the adhesive allows the polyester polyol to provide thermal stability while the polyisocyanate provides bonding capability, achieving both retorting resistance and basic adhesive function.
2Stability of the object's composition
If the adhesive is designed to maintain flexibility under high-temperature conditions, then retorting resistance is improved, but the adhesive may lose bonding strength
Solution Approach 1:
The patent carefully controls the molecular weight and structural parameters of the polyester polyol to achieve the right balance between flexibility and bonding strength. By adjusting the hydroxyl value and molecular structure, the adhesive maintains flexibility for retorting resistance while preserving sufficient bonding strength through the polyisocyanate crosslinking.
3Reliability
If the adhesive is used for packaging strong-smelling products, then content resistance is required, but conventional adhesives decompose or peel under these conditions
Solution Approach 1:
The patent modifies the chemical parameters of the adhesive by using a polyester polyol with specific functional groups (ether oxygen atoms and positioned hydroxyl groups) that are resistant to chemical attack from low-molecular-weight compounds. This chemical parameter change provides inherent resistance to decomposition and peeling when exposed to fragrances and other content molecules.
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 adhesive maintains adhesion and flexibility under high-temperature conditions and in the presence of low-molecular-weight migrants, preventing decomposition and peeling, thus ensuring effective packaging performance.
Implementation Method 1
a polyol composition (A) including a polyester polyol (A1); and a polyisocyanate composition (B) including a polyisocyanate compound (B1)
Data Source
AI summary
Provided are a laminating adhesive, a laminate, and a packaging material which are excellent in retorting resistance and content resistance. The adhesive includes a polyol composition (A) including a polyester polyol (A1), and a polyisocyanate composition (B) including a polyisocyanate compound (B1), in which the polyester polyol (A1) is a reaction product of a composition including a polycarboxylic acid and a polyhydric alcohol, the polycarboxylic acid including a tetramer acid. The laminate and the packaging material are produced using the adhesive.