Polyolefins hydroxybenzophenones

Poly[styrene-co-(2-hydroxy-4 -vinylbenzophenone)] was less efficient in PS than 2-hydroxy-4-methoxybenzophenone [334]. Similarly, PE films doped with 4-dodecyloxy-2-hydroxybenzophenone (0.1 mol%) were more stable than PE doped with copolymers of ethylene with polymerisable benzophenones having a comparable content of chromophores [54]. The efficiency of a SAN type LS, a terpolymer of 2-hydroxy-4-(4-vinylbenzyloxy)benzophenone with acrylonitrile and styrene did not exceed that of conventional LS [84]. No efficiency loss of 2-hydroxy-4-methacryloyloxybenzophenone in ABS was observed after bonding into a terpolymer with styrene and acrylonitrile. The homopolymer was slightly inferior to both the monomer and terpolymer [84]. A better protection of PP was provided by poly[(2-hydroxy-3-allyl-4-methoxyphenylbenzophenone)-co-dibutyl maleate] than with 2-hydroxy-3-allyl-4-methoxybenzophenone [335] (stabilization tests were performed in the presence of phenolic antioxidants). A comparable or better light stabilizing efficiency of poly[vinyl acetate-co-(5-methylacryloyloxy salicylate)] or poly(2-allylphenyl salicylate-co-dioctyl maleate) than that of alkyl-phenyl salicylates was observed in polyolefins [335]. 

UV absorber, PMMA 2-[2-Hydroxy-3,5-d i-( 1,1 -di methyl benzyl) phenyl]-2H-benzotri azole UV absorber, polishes Phenyl salicylate UV absorber, polyamide 2-[2-Hy d roxy-3,5-d i -(1,1 -d i methyl benzyl) phenyl]-2H-benzotri azole UV absorber, polyester Benzophenone-3 Bis [2-hydroxy-5-methyl-3-(benzotriazol-2-yl) phenyl] methane UV absorber, polyester dyed fabrics Benzophenone-1 UV absorber, polyesters Benzophenone-2 Benzophenone-6 Bis [2-hydroxy-5-t-octyl-3-(benzotriazol-2-yl) phenyl] methane Bumetrizole 4-Dodecyloxy-2-hydroxybenzophenone Drometrizole Octrizole Phenyl salicylate 2,4,4 -Trihydroxybenzophenone UV absorber, polymers 4-(2-Acryloyloxyethoxy)-2-hydroxybenzophenone polymer Benzophenone-1 Dipropylene glycol salicylate Drometrizole 2,4,4 -T ri hydroxybenzophenone UV absorber, polymethyl methacrylate 2,4,4 -Tri hydroxybenzophenone UV absorber, polyolefins Bumetrizole 2-(3, 5 -Di-t-butyl-2 -hydroxyphenyl)-5-chlorobenzotriazole 2-(2 -Hydroxy-3,5 -di-t-amylphenyl) benzotriazole Nickel bis [0-ethyl (3,5-di-t-butyl-4-hydroxybenzyl)] phosphonate Nickel diisobutyidithiocarbamate UV absorber, polyvinyl butyral Octrizole UV absorber, PP... 

Reaction of resorcinol with benzotrichloride or benzoyl chloride yields 2,4-di-hydroxybenzophenone, which, with octyl chloride, forms 2-hydroxy-4-octyloxy-benzophenone, one of the most important UV absorbers for the stabilization of polyolefin films. 

The most effective light stabilizers based on benzophenone are cited in Table 11. Their recommended concentrations for polyolefins are 0.2-1.5% by weight. Light stabilizers based on benzophenone can be divided into two basic tsqjes mono-2-hydroxybenzophenones and 2,2 -dihydroxy-benzophenones. 

Phenyl-substituted p-hydroxybenzoates (Structure 4) have been used as light Stabilizers in polyolefins for some time. They were shown to operate through a photo-Fries rearrangement to give a more effective 2-hydroxy-benzophenone product by the following reaction sequence (Scheme 4) to give 2-hydroxybenzophenones as products [1,2]. Obviously for such a reaction to occur, the original stabilizer must absorb appreciably in... 

Allen, N. S., Edge, M. et al. Effect of processing on the thermal and photooxidative behaviour of 2-hydroxybenzophenone stabilizers in polyolefin fihns Influence of 2,2,6,6-tetramethylpiperidine, Polymer Degradation and Stability, 44 (1994), p. 99 - 105... 

Commercial light stabilizers for polyolefins of the 2-hydroxybenzophenone class ... 

Allen, N.S., Edge, M., He, J., Chen, W., Kikkawa, K., Minagawa, M. Thermal and photooxidative behaviour of 2-hydroxybenzophenone stabilisers in polyolefin films Effeet of 4-butoxy-4-amino-tetramethylpiperidine substitution. Polym. Degrad. Stab. 42, 293-306 (1993)... 

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