Functionalized Particles for Pressure-Sensitive Adhesive Crosslinking
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Solution Overview
Problem
Pressure-sensitive adhesives (PSAs) face challenges in achieving a balance between good processing properties and product properties, particularly coatability, due to crosslinking which often leads to reduced fluidity and increased elasticity, making solvent-free processing difficult and resulting in inhomogeneous coatings.
Innovation Solution
A process involving functionalized particles with blocked or deactivated functionalities that are linked to polymeric constituents through thermal or radiation energy during or after coating, allowing for controlled crosslinking and improved cohesion without compromising processing characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crosslinking is performed to improve cohesion and adhesion properties, then bond strength and holding power increase, but fluidity decreases and elasticity increases making coating difficult
Solution Approach 1:
The particles are pre-functionalized with blocked or deactivated functionalities before coating, allowing them to be incorporated into the PSA formulation without causing premature crosslinking. The actual crosslinking action is postponed until after coating when thermal or radiation energy is applied, thus preserving fluidity during processing while enabling cohesion enhancement afterward.
Solution Approach 2:
The functional groups on particle surfaces are transformed from blocked/deactivated state to active state through parameter changes (thermal energy or radiation energy) after coating. This parameter change activates the crosslinking functionality at the appropriate stage, resolving the contradiction between maintaining fluidity for coating and enabling crosslinking for strength.
2Stability of the object's composition
If crosslinking is performed before coating to enhance product properties, then cohesion improves, but inhomogeneous coatings result due to reduced fluidity
Solution Approach 1:
Particles are pre-functionalized with blocked functionalities that prevent premature crosslinking during mixing and coating operations. This preliminary preparation ensures uniform distribution of functional particles throughout the PSA formulation without causing early network formation, thereby maintaining coating homogeneity while preparing for subsequent cohesion enhancement.
Solution Approach 2:
The crosslinking functionality is extracted or separated from the mixing/coating process by using blocked functional groups. The actual crosslinking action is removed from the coating stage and postponed to a separate post-coating activation stage, preventing interference with coating homogeneity while preserving the ability to enhance cohesion.
3Device complexity
If solvent-free processing is used to improve environmental properties and simplify formulation, then processing complexity reduces, but achieving uniform coating becomes difficult due to high elasticity
Solution Approach 1:
Blocked functional groups are incorporated into the solvent-free PSA formulation in advance, preventing premature crosslinking that would otherwise cause high elasticity and coating difficulties. This preliminary configuration allows solvent-free processing to proceed with good flow properties while reserving crosslinking for post-coating activation.
Solution Approach 2:
The physical state of functional groups is changed from blocked to active through thermal or radiation energy input after coating. This parameter change enables the solvent-free formulation to maintain processability during coating while achieving the desired crosslinked structure and uniformity after activation.
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 solution enables PSAs with enhanced cohesion and adhesion while maintaining good processing properties, such as increased pot life and improved coatability, resulting in higher holding power and bond strength without melt inhomogeneities.
Implementation Method 1
the particles can be linked to at least one kind of polymeric constituents of the PSA formulation by exposure to, in particular, thermal energy and/or radiation energy
Implementation Method 2
the particles can be linked to at least one kind of polymeric constituents of the PSA formulation by exposure to, in particular, thermal energy and/or radiation energy, in particular to electromagnetic radiation or particulate radiation
Implementation Method 3
the particles can be linked to at least one kind of polymeric constituents of the PSA formulation by exposure to, in particular, thermal energy and/or radiation energy, in particular to electromagnetic radiation or particulate radiation and/or to sound energy
Data Source
AI summary
The invention relates to a process for preparing a pressure-sensitive adhesive based on at least one polymer, in the course of which said at least one polymer is crosslinked, the polymer having functional groups Y and having been admixed, further, with at least one kind of functionalized particles which have at least one nonpolymeric base unit, wherein the particles having a surface modification of the base unit, the surface modification of the particles having at least one kind of functional groups Z, which can not undergo any reaction with the functional group Y and is converted into group X by thermal energy, electromagnetic radiation, particulate radiation and/or sound energy and the crosslinking of the polymer being brought about at least in part by a reaction of the functional groups X of the particles and the functional groups Y of the polymer, and further to pressure-sensitive adhesives based on at least one crosslinked polymer component, the crosslinking of the polymer component being brought about at least in part by incorporation of the functionalized particles, the particles having at least one nonpolymeric base unit and also a surface modification of this base unit, and the surface modification of the particles having at least one kind of functional groups Z which, after conversion to group X by way of thermal energy, electromagnetic radiation, particulate radiation and/or sound energy, are capable of reacting with functional groups Y present in the polymer component, and also to the use of surface-modified functionalized particles having a nonpolymeric base unit as crosslinking reagents for crosslinking polymers for preparing pressure-sensitive adhesives.