Carbonyl derivatives of 1-phenylindan suitable for use as polymerization photoinitiators, their preparation and use

A compound of general formula:

• ##STR13## where:
• n:
• ranges from 0 to 1
• R, R.sup.1, R.sup.2 :
• which are identical or different, each independently represent H, C.sub.1 -C.sub.3 alkyl
• Q:
• represents a ##STR14## group in which R.sup.3, R.sup.4, which are identical or different, independently represent:
• C.sub.1 -C.sub.8 alkyl
• together represent a C.sub.3 -C.sub.7 polyalkylene group
• together are coincident in an oxygen atom
• X:
• is Cl, OH, or OR in which R has the aforesaid meaning,
• having the property of acting as a photosensitive agent in the radical polymerisation of compounds with ethylenic double bonds to which it is added in an effective quantity.

A photopolymerisable composition comprising compounds or mixtures of compounds with olefinic double bonds and at least one compound of general formula:

• ##STR15## where:
• n:
• ranges from 0 to 1
• R, R.sup.1, R.sup.2 :
• which are identical or different, each independently represent H, C.sub.1 -C.sub.3 alkyl
• Q:
• represents a ##STR16## group in which R.sup.3, R.sup.4, which are identical or different independently represent:
• C.sub.1 -C.sub.8 alkyl
• together represent a C.sub.3 -C.sub.7 polyalkylene group
• together are coincident in an oxygen atom
• X:
• is Cl, OH, or OR in which R has the aforesaid meaning,
• in a quantity of between 0.1 and 10 parts by weight per 100 parts of composition.

A process for preparing carbonyl derivatives of 1-phenylindan, or a mixture thereof, having the following general formula:

• ##STR17## where:
• n:
• ranges from 0 to 1
• R, R.sup.1, R.sup.2 :
• which are identical or different, each
• independently represent H, C.sub.1 -C.sub.3 alkyl
• Q:
• represents a ##STR18## group in which R.sup.3, R.sup.4, which are identical or different independently represent:
• C.sub.1 -C.sub.8 alkyl
• together represent a C.sub.3 -C.sub.7 polyalkylene group
• together are coincident in an oxygen atom
• X:
• is Cl, OH, or OR in which R has the aforesaid meaning,
• consisting of:
• heating a compound of styrene type to a temperature of between -10.degree. C. and 150.degree. C. for a time of between 0.5 and 8 hours in the presence of an acid catalyst but in the absence of solvent;
• separating the acid catalyst from the reaction mixture;
• then treating in known manner said reaction mixture containing compounds with a 1-phenylindan structure to convert them into the desired carbonyl derivatives.