Crosslinking of photoiniator-initialized polyacrylates
View Patent ↗A process for increasing the molecular weight of polyacrylates, characterized in that polyacrylates which are functionalized at least on one part of their chain ends by photoinitiator groups X are exposed to actinic radiation, so that a direct linking reaction of the polyacrylates takes place.
1. A process for increasing the molecular weight of polyacrylates, wherein polyacrylates which are functionalized at least on one part of their chain ends by photoinitiator groups X are exposed to actinic radiation, so that a direct linking reaction of the polyacrylates takes place.
2. A process for increasing the molecular weight of polyacrylates, wherein polyacrylates which are functionalized at least on one part of their chain ends by suitable photoinitiator groups X are exposed to actinic radiation in the presence of at least one crosslinker substance, so that a linking reaction of the polyacrylates which includes the crosslinker substance takes place.
3. A process according to claim 1 or 2 , wherein the polyacrylates functionalized with photoinitiator groups have an average molecular weight (number average) M n in the range from 2 000 to 1 000 000 g/mol.
4. A process according to claim 1 or 2 , wherein the photoinitiator groups are those of UV photoinitiators of the Norrish I and/or Norrish II type.
5. A process according to claim 1 or 2 , wherein the increase in the molecular weight comprises a crosslinking reaction.
6. A process as claimed in claim 1 or 2 , wherein the linking reactions link the polyacrylate molecules linearly to one another.
7. A process as claimed in claim 1 or 2 , wherein the polyacrylates functionalized with photoinitiator groups contain at least one chain branching site.
8. A process as claimed in claim 7 , wherein the polyacrylates have at least three photoinitiator groups.
9. A process as claimed in claim 1 or 2 , wherein at least one difunctional or polyfunctional vinyl compound is added to the polyacrylate functionalized with photoinitiator groups.
10. A pressure sensitive adhesive for single-sided and double-sided pressure sensitive adhesive tapes comprising at least one Polyacrylate prepared by the process of claim 1 or 2 .
11. A process according to claim 9 , wherein said vinyl compound is a methacrylate-based compound.
12. A process according to claim 9 , wherein said vinyl compound is an acrylate-based compound.