Pressure Sensitive Adhesive Co-Extrusion Solvent Elimination
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Solution Overview
Problem
Current protective films used for materials like metal and glass plates face environmental pollution issues due to solvent use in solution coating processes and require repeated coating to achieve sufficient thickness, necessitating a novel adhesive composition with high initial viscosity suitable for melting gel co-extrusion processes.
Innovation Solution
A pressure sensitive adhesive composition comprising 30-45 parts by weight of a tackifier and 55-70 parts by weight of a polymer, where the polymer includes at least one block copolymer. The block copolymer consists of a vinyl aromatic block and a conjugated diene block, meeting specific weight percentage conditions for vinyl aromatic monomer and vinyl group content, enabling high initial viscosity and suitability for co-extrusion processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solution coating process is used to form protective film, then adhesive layer can be formed on substrate, but large amount of solvent causes environmental pollution and repeated coating is needed to achieve sufficient thickness
Solution Approach 1:
The patent changes the physical state of the adhesive from solution-based to melt-based processing. The adhesive composition is designed to be processed in molten state through co-extrusion, eliminating the need for solvents entirely. This parameter change from solution coating to melt co-extrusion resolves the environmental pollution issue while maintaining adhesive layer formation capability
Solution Approach 2:
The patent replaces the chemical solution coating process with a mechanical co-extrusion process. Instead of applying adhesive through solution spraying or dipping, the adhesive is integrated into the extrusion process where materials are forced through a die in molten state, creating a laminate structure. This substitution eliminates solvent usage and achieves both adhesive bonding and protective film formation in one process
2Ease of manufacture
If solution coating process is used to form protective film, then adhesive layer can be applied to substrate, but repeated coating process is required to achieve sufficient thickness
Solution Approach 1:
The patent merges the adhesive layer formation with the protective film formation into a single co-extrusion process. Both layers are extruded simultaneously in one operation, creating an integrated laminate structure. This eliminates the need for repeated separate coating operations and achieves sufficient thickness in a single pass
Solution Approach 2:
The adhesive composition is pre-formulated with specific polymer ratios and additives to ensure it achieves sufficient viscosity and bonding characteristics during the single co-extrusion process. The composition is designed so that the adhesive layer reaches its functional thickness and bonding capability in one extrusion cycle, eliminating the need for repeated coating
3Reliability
If conventional adhesive composition is used, then adhesive properties can be achieved, but medium initial viscosity is not suitable for melting gel co-extrusion process
Solution Approach 1:
The patent modifies the viscosity parameters of the adhesive composition by selecting specific polymer ratios and additives. The composition is formulated to achieve medium initial viscosity that is suitable for melt co-extrusion processing. This parameter adjustment allows the adhesive to be processed in molten state while maintaining reliable adhesive properties after cooling and bonding
4Ease of manufacture
If block copolymer with specific vinyl aromatic monomer content is used, then high initial viscosity is achieved for co-extrusion, but adhesive bonding strength must be maintained
Solution Approach 1:
The patent uses a composite adhesive composition combining specific block copolymers with vinyl aromatic monomers and conjugated diene blocks in controlled ratios. This composite formulation achieves the right balance between initial viscosity for co-extrusion and final adhesive bonding strength. The specific combination of polymer components provides both processability and bonding performance
Solution Approach 2:
The patent optimizes the molecular weight and composition parameters of the block copolymer to achieve the desired balance. By controlling the vinyl aromatic monomer content (15-25 wt%) and conjugated diene block vinyl group content (<45 wt%), the composition achieves medium initial viscosity for co-extrusion while maintaining sufficient adhesive bonding strength through proper polymer architecture and composition
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 composition exhibits high initial viscosity, allowing for effective formation of a laminate via co-extrusion molding, and demonstrates high peeling strength and loop tack, ensuring close contact with substrates like metal or plastic, while avoiding environmental pollution concerns.
Implementation Method 1
a novel adhesive composition, which exhibits characteristics of rubber, has a medium (or high) initial viscosity and is suitable to form a laminate by melting gel co-extrusion process
Implementation Method 2
This protective film can force a substrate to be adhered to a coating surface of a plate material via an adhesive layer
Data Source
AI summary
A pressure sensitive adhesive composition and a protective film employing the same are provided. The pressure sensitive adhesive composition includes 30-45 parts by weight of a tackifier and 55-70 parts by weight of a polymer. The polymer includes at least one block copolymer. The block copolymer includes a vinyl aromatic block polymerized by a vinyl aromatic monomer and a conjugated diene block polymerized by a conjugated diene monomer. The block copolymer meets one of the following conditions: (1) the content of the vinyl aromatic monomer is from 15 wt % to 25 wt % and the content of the vinyl group of the conjugated diene block is less than or equal to 45 wt % or, (2) the content of the vinyl aromatic monomer is from 10 wt % to 15 wt % and the content of the vinyl group of the conjugated diene block is less than or equal to 45 wt %, or greater than or equal to 60 wt %.