Crosslinked Polyacrylate Adhesive Tape for Display Shock Absorption
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Solution Overview
Problem
Existing adhesive tapes fail to provide effective shock absorption and bending stress compensation for both glass and transparent plastics in consumer electronics, and they lack high temperature cohesion resistance, making them unsuitable for protecting display modules from mechanical impacts and temperature fluctuations.
Innovation Solution
A double-sided adhesive tape with a thickness of 100 to 300 µm, comprising a backing layer and two outer layers of pressure-sensitive adhesive, where at least one adhesive is a crosslinked product of a polyacrylate polymer composition with specific monomers and a crosslinker, optimized for glass transition temperature and frequency to ensure shock absorption and temperature resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass is used as protective window, then scratch resistance and UV resistance are improved, but shock resistance and impact protection deteriorate
Solution Approach 1:
The patent employs a composite adhesive system combining polyacrylate polymer with epoxy crosslinker to create a material that exhibits both flexibility for shock absorption and strength for bonding. The crosslinked network structure provides mechanical strength while the polymer matrix maintains elasticity, resolving the contradiction between glass hardness and shock resistance.
Solution Approach 2:
The patent modifies the adhesive properties by controlling the crosslinking degree through specific ratios of crosslinker to polymer (0.05-0.50 by weight). This parameter adjustment allows the adhesive to transition between rigid and flexible states, enabling it to compensate for both the brittleness of glass and the softness of plastics while maintaining strong bonding.
2Reliability
If polymer sheets are used as protective window, then shock absorption and impact resistance are improved, but scratch resistance and UV resistance deteriorate
Solution Approach 1:
The crosslinked polyacrylate-epoxy adhesive system provides a composite structure that combines the flexibility needed for impact absorption with the crosslinked network that provides surface hardness and scratch resistance, thereby protecting polymer windows without sacrificing impact resistance.
3Temperature
If adhesive tape with high crosslinking is used, then temperature cohesion resistance is improved, but shock absorption and bending stress compensation deteriorate
Solution Approach 1:
The patent precisely controls the crosslinking degree by limiting the crosslinker content to 0.05-0.50 by weight relative to the polymer. This optimized parameter range ensures sufficient thermal stability while maintaining enough flexibility for shock absorption. The glass transition temperature is specifically adjusted to balance these competing requirements.
Solution Approach 2:
The adhesive is designed with heterogeneous properties: the crosslinked network provides localized thermal stability and strength, while the uncrosslinked polymer segments maintain flexibility and shock absorption capability. This spatial differentiation of properties resolves the contradiction between temperature resistance and shock absorption.
4Reliability
If adhesive tape with low resin content is used, then shock absorption is improved, but bonding strength and adhesion to substrates deteriorate
Solution Approach 1:
The patent creates a composite adhesive where the polyacrylate polymer provides shock absorption through its viscoelasticity, while the epoxy crosslinker enhances bonding strength through chemical bonding to substrates. The synergistic combination allows low resin content (5-20 parts per hundred polymer) while maintaining both shock absorption and adhesion.
Solution Approach 2:
The patent replaces purely mechanical interlocking adhesion with chemical bonding through crosslinking. The epoxy groups form covalent bonds with substrate surfaces, providing strong adhesion without requiring high resin content or thick adhesive layers, thereby preserving shock absorption capabilities.
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 tape effectively compensates for bending stresses and absorbs shock impacts, maintaining cohesion across a wide temperature range, thus providing enhanced protection for electronic devices with transparent components.
Implementation Method 1
the adhesive tape effectively compensates for bending stresses and absorbs shock impacts
Implementation Method 2
tapes with a certain degree of shock absorption are typically used for bonding glass, thus cushioning mechanical impacts
Implementation Method 3
the adhesive tape should preferably also possess high temperature cohesion resistance
Implementation Method 4
at least one of the adhesive layers is the crosslinking product of a polymer mass comprising at least the following components: A) a polymer component comprising 88 to 100 wt.% of one or more polyacrylates
Implementation Method 5
for bonding plastics (polymer discs), the focus is more on compensating for bending stresses
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a double-sided adhesive tape, comprising a carrier layer and two exterior pressure-sensitive adhesive compound layers, wherein at least one of the pressure-sensitive adhesive compounds is the crosslinking product composed of a polymer compound which comprises at least the following components: A) a polymer component (component A) comprising 88 to 100 wt % of one or more polyacrylates (component A1) composed of at least: a) 1 to 15 wt %, relative to component A1, of one or more monomers having at least one ethylenically unsaturated bond, each being selected such that the glass transition temperatures TG of the corresponding homopolymers composed of the respective monomers are at least 0°C (monomers a), wherein at least some of the monomers (a) still comprise at least one carboxylic acid (monomers a1), b) 85 to 99 wt %, relative to component A1, of one or more monomers from the group of acrylic acid esters and methacrylic acid esters, each being selected such that the glass transition temperatures TG of the corresponding homopolymers composed of the respective monomers are not higher than -30°C (monomers b), B) at least one covalently cross-linking bifunctional or polyfunctional crosslinking agent (component B), wherein components A and B in total amount to at least 95 wt % of the polymer compound, and wherein the at least one crosslinking agent is added in a quantity such that the quantity ratio V = nZ/nP of the substance quantity nZ of the crosslinking-active centers of the crosslinking agent to the theoretical substance quantity nP of the macromolecule of polymer component A1 has a value between 0.15 and 0.60, wherein the substance quantity nZ of the crosslinking-active centers of the crosslinking agent is obtained from the mass mV of the crosslinking agent, multiplied by the number f of crosslinking-active centers per crosslinking agent molecule, divided by the molecular weight Mv of the crosslinking agent, that is, nZ= f.mV/MV, and the theoretical substance quantity nP of the macromolecule of polymer component A1 is obtained from the mass mP of the polymer component in the pressure-sensitive adhesive compound, divided by the average molecular weight Mn,P of said component, that is nP = mP/Mn,P.