Study On Preparation And Properties Of UV-cured Polyurethane Release Agents

The release films have anti-sticking and protective effect,which are prepared by coating release agents with special molecular structure on the surface of the substrate.Currently,the main release agents are solvent-based silicone release agents on the market.But the catalysts for such release agents are platinum-based compounds with high cost.In addition,organic dilution solvents must be used during the coating process,which inevitably causes environmental problems and is harmful for the human body.If the release film made of the silicone release agent is left for a long time during use,different degrees of silicon transfer may occur,resulting in a sticking phenomenon,which does not provide the proper anti-sticking and protection effect.Therefore,the development of release agents with high performance,environmentally friendly coating and low cost has very important research significance.In this paper,a series of release film samples were prepared by incorporating photocuring cross-linking technology into polyurethane release agents,and their properties were tested.The research contents of full text are exhibited as follows:?1?A fluorine-containing chain extender?FMPG?was prepared using amidation reaction in this paper.Then,a series of UV-cured fluorosilicon block polyurethane release agents?FSPU?were then synthesized with hydroxypropyl-terminated polydimethylsiloxane?PSi?,fluorine-containing chain extender?FMPG?,isophorone diisocyanate?IPDI?and 2-hydroxyethyl methacrylate?HEMA?as reactants.Finally,a series of fluorosilicone release film samples were prepared by using the obtained release agents as the main resin and the reactive diluent hexafluorobutyl methacrylate?HFMA?under the action of 1173 photoinitiator by UV curing.The results showed that the release agents had good compatibility with the reactive diluent,and all the samples had excellent heat resistance and solvent resistance.With the increase of the content of fluorine-containing chain extender,the contact angles of H₂O and CH₂I₂ on the surface of the release films increased to 116.54°and 80.11°,respectively,and the surface free energy decreased from 22.03 mN/m to 17.81 mN/m.The peel strength,permanent peel strength and aging peel strength were reduced from 6.94 g/25 mm,7.55 g/25 mm and8.23 g/25 mm to 5.70 g/25 mm,6.31 g/25 mm and 6.99 g/25 mm,respectively,which were light release types.And the adhesion can be up to grade 1 and above.?2?A UV-cured polysiloxane polyurethane release agent?SPU?was prepared in this paper by using the above reactants other than the fluorine-containing chain extender.The release agent was used as the main resin while trifluoroethyl methacrylate?TFMA?,hexafluorobutyl methacrylate?HFMA?and dodecafluoroheptyl methacrylate?DFMA?were selected as three different reactive diluents.A series of fluorosilicone release films were prepared by UV curing with the help of 1173 photoinitiator.The results showed that the release agent had good compatibility with different active dilution monomers,and all samples had excellent thermal stability and solvent resistance.With the increase of the fluorine-containing chain length of the diluted monomer,the contact anglesa of H₂O and CH₂I₂ on the surface of the release films increased to 119.46°and 82.25°,respectively,and the surface free energy decreased from 24.07 mN/m to 16.70 mN/m.The peel strength,permanent peel strength and aging peel strength were reduced from7.42 g/25mm,8.03 g/25mm and 8.55 g/25mm to 5.36 g/25mm,5.87 g/25mm and 6.54g/25mm,respectively,which were light release types.And the adhesion can be up to grade 1 and above.?3?A UV-cured butadiene urethane acrylate release agent?HTPU?was prepared by the catalysis of dibutyltin laurate?DBTDL?with polyhydroxybutadiene?HTPB?,octadecyldiethanolamine?ODDEA?,isophorone diisocyanate?IPDI?and hydroxyethyl methacrylate?HEMA?as reactants in this paper.A series of non-silicone release film samples were prepared by using the obtained release agent as the main resin with three different reactive diluents such as isooctyl methacrylate?IOMA?,lauryl methacrylate?LMA?and octadecyl methacrylate?ODMA?under the action of 1173 photoinitiator by UV curing.The results showed that the release agent had good compatibility with different reactive diluents,and all the samples had excellent heat resistance and solvent resistance.When the diluted monomer was octadecyl methacrylate?ODMA?and the addition amount was 30 wt.%,the contact angles of H₂O and CH₂I₂ on the surface of the release films were 119.46°and 82.25°,respectively,and the surface free energy was17.43.mN/m.The peel strength,permanent peel strength and aging peel strength were27.65 g/25 mm,28.14 g/25 mm and 30.64 g/25 mm,respectively.At this time,the peel strength of the release film was low and the adhesion was high,up to grade 0,and the release property was excellent.