Patent GB-862276-A (GB)
Title: Photosensitive polyamide resin molding powders
IPC: G03F5/20
Filed: 1958-04-15
Abstract: A photo-sensitive moulding powder comprises (i) a photo-sensitive synthetic polyamide composition comprising an unsaturated polyamide bearing stilbene units and/or a polyamide admixed with a photo-sensitive ethylenically unsaturated monomer capable of photopolymerizing or cross-linking with the polyamide, a and (ii) a polymerization inhibitor of the formula <FORM:0862276/IV (a)/1> <FORM:0862276/IV (a)/2> where R is hydrogen, an alkyl or alkoxy radical having one to five carbon atoms or an arylalkoxy radical having six to eleven carbon atoms, R1 is as R or an hydroxy radical and X is a salt-forming anion.  Specified photopolymerization inhibitors are pyrogallol, hydroquinone, methylene blue, quinone, t-butyl catechol, methyl hydroquinone, hydroquinone monobenzyl ether, amyl qiunone, amyloxyhydroquinone, n-butyl phenol, phenol and hydroquinone monopropyl ether.  Many unsaturated monomers are specified.  Specified photo initiators include benzil, benzoin, benzaldehyde, benzophenone, p - chlorobenzophenone, p - benzoyl benzoic acid, p,p1-dimethylaminobenzophenone, p - hydroxybenzophenone, p,p1 - dihydroxybenzophenone, p,p1 - dichlorobenzophenone, p - methoxybenzophenone, benzoin acetate, benzilic acid, acetophenone and benzoyl peroxide.  Fillers, e.g. polyamides, glass fibres, polyethylene, silicates, clays and alumina may be present in the compositions. The compositions may be made by grinding or by solution of the components in a common solvent. Polymerization is effected by exposing the composition to a source of actinic light, the unexposed areas being dissolved away.  In the examples: (1) an interpolyamide is made from e -caprolactam, dimethyl 4,4-stilbene dicarboxylic acid and hexamethylene diamine in the presence of pyrogallol, the reaction product being comminuted, pressed into a sheet and exposed to light; (2), (8) and (9) an interpolyamide is made from e -caprolactam, hexamethylene diammonium adipate and hexamethylene diammonium sebacate, the product being finely divided, mixed with benzophenone, methylene blue and N,N1-methylene bisacrylamide, moulded into a sheet or plate and exposed to light; (3) the polyamide of Example (1) is mixed with methylene blue, N,N-methylene bisacrylamide and benzophenone, cast into a film on a glass plate and exposed to light; (4) a plaque comprising a mixture of polyhexamethylene adipamide benzophenone, 5-acrylylamino-N-allyl caproamide and methylene blue is exposed to light; (5) a plaque comprising a mixture of methylene blue, benzophenone, N,N1-methylene bisacrylamide and an hydroxyethyl polyamide made by reacting an interpolyamide of e -caprolactam, hexamethylene diammonium adipate and hexamethylene diammonium sebacate with ethylene oxide is exposed to light; (6) and (7) a plate comprising a mixture of an interpolyamide similar to that of Example (2), benzonphenone, methylene blue and N,N1-methylene bismethyl acrylamide is exposed to light; and (13) a composition of an interpolymer similar to that of Example (2), N,N1-methylene bis acrylamide, benzophenone and hydroquinone is moulded into plates with or without cotton fibre and exposed to light.  Examples (10), (11), (12) and (14) describe the preparation and exposure to light of printing plates made from the composition of Example (9) containing: (10) cotton fibres; (11) polyhexamethylene adipamide cloth; (12) glass fibre cloth; and (14) asbestos fibres.  U.S.A. Specifications 2,071,250, 2,071,253, 2,130,523, 2,320,088, 2,430,860 and 2,441,057 are referred to.