Cinnamates and Related Types

Cinnamate-type UV absorbers have been patented by Bayer AG [66, 67] and Eastman Kodak/Eastman Chemical [68-81] for incorporation into polyalkylene terephthalates, mainly as reactive species incorporated into the polymer backbone. More recently low molecular weight additives of this type, which may or may not react into the polymer, have been commercialised by Clariant [82] and BASF AG [83-86]. 

Intellectual property assigned to Bayer covers benzylidene malonates and benzylidene bis-malonates [66], and includes the use of this type of stabiliser in the manufacture of polyesters [67]. It is likely 

The development of this type of chemistry built into polyesters was part of an extensive effort undertaken by Eastman over a number of years to develop various grades of self-coloured, UV-brightened and UV-stabilised polyester fibres. Initial polyesters utilised reactive versions of the simplest cinnamate chemistry, such as  

Also noted were PET copolymerised with these structures and with naphthalene dicarboxylic acid [79], and PEN itself with built-in cinnamate-type moieties [81]. 

Sanduvor PR-25 has been assessed as a UV stabiliser in a variety of polymers, including PET [82], where it is said to be photo-graftable to 

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