Tack-Free Hot Melt Adhesive Coating Process
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Solution Overview
Problem
Hot melt adhesives, particularly hot melt pressure sensitive adhesives, face handling difficulties and contamination risks due to their tacky nature, and existing packaging methods lead to carbonization and clogging issues in melt pots, as well as high costs and inefficiencies in storage and transportation.
Innovation Solution
A process involving the application of a tack-free coating material in liquid or molten form to the surface of hot melt adhesive masses, which solidifies within 60 seconds or less, allowing for improved handling and eliminating the need for packaging films that cause carbonization and clogging, while ensuring compatibility with the adhesive's melting behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If HMA is cast in molten state inside silicone coated containers and cooled at ambient conditions, then the product can be packaged and stored, but the cooling period is long, additional shelves are required, and hazard potential is high
Solution Approach 1:
The invention changes the temperature parameter by applying heat treatment to the packaging material containing the HMA. By heating the packaging to temperatures between 40-100°C for 1-24 hours, the HMA transforms from a solidified state back to a more fluid state, eliminating the need for long cooling periods and enabling faster packaging turnover
Solution Approach 2:
The invention performs preliminary heating of the packaging material with HMA before final packaging operations. This pre-heating step softens the HMA in advance, making it easier to handle and package without requiring extended cooling periods afterward, thus accelerating the overall manufacturing process
2Reliability
If high tack HMPSA formulations are used to meet application requirements, then adhesion performance is improved, but the product easily deforms and cold flows unless supported during shipment
Solution Approach 1:
The invention applies temperature control as a parameter to manage the physical state of high-tack HMPSA. By maintaining elevated temperatures during packaging and storage, the adhesive remains in a semi-fluid state that prevents deformation and cold flow, while retaining its high adhesion performance when applied
Solution Approach 2:
The invention uses a silicone-coated packaging material as an intermediary between the high-tack HMPSA and the external environment. This intermediary packaging provides support and containment that prevents deformation during storage and transport, while allowing the adhesive to maintain its tacky properties for effective bonding
3Ease of operation
If packaging films are used to protect tacky HMA during handling, then handling difficulty is reduced, but carbonization and clogging issues occur in melt pots
Solution Approach 1:
The invention employs disposable silicone-coated packaging materials that are designed to be used once and then discarded. These single-use packages protect the HMA during handling and transport without causing carbonization or clogging issues, as they are removed before the HMA is melted in the melt pot for application
Solution Approach 2:
The invention extracts or removes the packaging material from the HMA processing system before the HMA enters the melt pot. By separating the protective packaging function from the melting process, the harmful effects of carbonization and clogging are eliminated while retaining the handling benefits of packaged HMA
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 process results in a tack-free hot melt adhesive mass that can be easily handled and transported, reducing contamination risks and eliminating carbonization and clogging issues in melt pots, while allowing for flexible selection of coating materials that enhance product performance and end-use properties.
Implementation Method 1
the coating material being applied is solidified and fixed within 60 seconds or less, preferably 30 seconds or less, but at least 0.1 seconds or more, e.g. in 0.1 to 30 seconds, on the surface of the HMA mass
Implementation Method 2
HMPSA in molten form is granulated or cut into small portions and subsequently solidified in a cooling medium, preferably in water
Data Source
AI summary
The present invention relates to a process for preparing hot melt adhesive (HMA), preferably hot melt pressure sensitive adhesive (HMPSA), having a substantially tack-free coating, wherein said HMA, preferably HMPSA, can be easily handled, packed and transported for further use.