Aqueous Dispersion Adhesive for Heat-Resistant Packaging Bonds
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Solution Overview
Problem
Existing adhesives face challenges in achieving both high heat resistance and cold resistance, particularly in hot filled packaging applications, and struggle with bonding on difficult substrates like acrylic and polycarbonate sheets, which require adhesives that can maintain strength and adhesion under varying environmental conditions.
Innovation Solution
The development of aqueous dispersions containing polymers, tackifying resins, waxes, or oils, which can be selectively activated through heat or pressure to form adhesive bonds, allowing for application at lower temperatures and on a variety of substrates, including hard-to-bond materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high molecular weight components are used to achieve high heat resistance, then heat resistance is improved, but application viscosity and adhesive properties deteriorate
Solution Approach 1:
The invention uses a composite adhesive system combining a polyolefin resin (providing heat resistance) with a polyester resin (providing adhesion and processability). This composite approach allows the adhesive to achieve both high heat resistance (from the polyolefin) and good application properties (from the polyester), resolving the contradiction between heat resistance and application viscosity.
2Strength
If softer or more amorphous components are added to improve adhesion, then adhesion is improved, but heat resistance deteriorates
Solution Approach 1:
The invention employs a composite resin system where the polyolefin resin (crystalline structure) provides heat resistance while the polyester resin (amorphous structure) provides adhesion. The synergistic combination allows the adhesive to maintain both strong adhesion and high heat resistance, eliminating the need to choose between these opposing requirements.
3Ease of operation
If conventional PSAs are used for easy application, then ease of application is improved, but strength and durability under environmental conditions deteriorate
Solution Approach 1:
The invention modifies the chemical composition parameters of the adhesive by incorporating specific polyester resins with particular glass transition temperatures and molecular weights. This parameter change enables the adhesive to maintain its adhesive properties at lower temperatures while achieving durable bonds that resist environmental factors like heat and humidity, thus improving reliability without sacrificing ease of application.
4Strength
If adhesives are applied to outgassing materials like acrylic and polycarbonate, then bonding is achieved, but bubbling and delamination occur
Solution Approach 1:
The invention adjusts the chemical composition parameters of the adhesive, specifically using polyolefin resins with appropriate molecular weights and polyester resins with suitable glass transition temperatures. These parameter changes enable the adhesive to bond effectively to outgassing materials while minimizing harmful effects like bubbling and delamination by improving compatibility and reducing stress.
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
These dispersions enable the formation of strong, durable adhesive bonds that withstand heat, cold, and environmental stress, improving the versatility and reliability of adhesives in packaging and other applications.
Implementation Method 1
selectively activating at least a portion of the coated substrate to form the adhesive bond
Implementation Method 2
selectively activating at least a portion of the coated substrate to form the adhesive bond
Implementation Method 3
a polymer capable of forming an adhesive
Data Source
AI summary
A method and composition for forming an adhesive bond is described. The method includes depositing an aqueous dispersion on a substrate to form a selectively activatable coating, the aqueous dispersion including (A) a polymer capable of forming an adhesive, (B) at least one dispersing agent; and (C) at least one of a tackifying resin, a wax, or an oil wherein the dispersion has at least one of an average particle size of from about 0.1 to about 100 microns and a polydispersity of less than 5; and selectively activating at least a portion of the coated substrate to form the adhesive bond.