Abstract: The invention relates polysilazane-containing coatings for increasing the light permeability of sun-facing covers of solar cells. The coating for surfaces contains at least one polysilazane of formula (1) —(SiRR?R?—NR??1)n- (1), wherein R?, R?, R?? are the same or different or represent an optionally substituted alkyl, aryl, vinyl or (trialkoxysilyl)alkyl group, n being an integer and n being chosen in such a manner that the perhydropolysilazane has a number average molecular weight of 150 to 150,000 g/mol, a solvent and a catalyst. The cured coating has a thickness of at least 0.50-10 micrometer, preferably 0.2 to 5 micrometer, especially preferred 0.5 to 1.5 micrometer. It is especially suitable as transmission-promoting coating for use in sun-facing covers of solar cells.

Abstract: The invention relates to a method for producing passivation layers on crystalline silicon by a) coating the silicon with a solution containing at least one polysilazane of the general formula (1): —(SiR?R?—NR??)-n, wherein R?, R?, R?? are the same or different and stand independently of each other for hydrogen or a possibly substituted alkyl, aryl, vinyl, or (trialkoxysilyl)alkyl group, wherein n is an integer and n is chosen such that the polysilazane has a number average molecular weight of 150 to 150,000 g/mol, b) subsequently removing the solvent by evaporation, whereby polysilazane layers of 50-500 nm thickness remain on the silicon wafer, and c) heating the polysilazane layer at normal pressure to 200-1000° C. in the presence of air or nitrogen, wherein upon tempering the ceramic layers release hydrogen for bulk passivation of the silicon.

Abstract: The invention relates to a method for producing passivation layers on crystalline silicon by a) coating the silicon with a solution containing at least one polysilazane of the general formula (1): —(SiR?R?—NR??)-n, wherein R?, R?, R?? are the same or different and stand independently of each other for hydrogen or a possibly substituted alkyl, aryl, vinyl, or (trialkoxysilyl)alkyl group, wherein n is an integer and n is chosen such that the polysilazane has a number average molecular weight of 150 to 150,000 g/mol, b) subsequently removing the solvent by evaporation, whereby polysilazane layers of 50-500 nm thickness remain on the silicon wafer, and c) heating the polysilazane layer at normal pressure to 200-1000° C. in the presence of air or nitrogen, wherein upon tempering the ceramic layers release hydrogen for bulk passivation of the silicon.

Abstract: A process for the production of N-acylaminophenols by the concurrent hydrogenation of a nitrophenol to an aminophenol and the acylation of the aminophenol with acyl anhydride takes place on a continuous basis in a stirred tank reactor in which liquid product is continuously withdrawn from the reactor. Of particular interest is the manufacture of acetaminophen, N-acetyl-p-aminophenol by continuous reaction of p-ntirophenol, hydrogen and acetic anhydride.

Abstract: Radiation-polymerizable composition which comprisesa) a constituent that can be polymerized by free radicals and has a boiling point above 100.degree. C.,b) a photoinitiator, andc) a copolymer comprising units ofc1) an .alpha., .beta.-unsaturated aliphatic carboxylic acid,c2) an alkyl, cycloalkyl or cycloalkenyl methacrylate, andc3) an alkyl, cycloalkyl or cycloalkenyl acrylateand has an acid number of 78 to 176 and a glass transition temperature of 290 to 340 K. The composition is characterized by its ready developability at a low acid number and its good resistance to alkaline etching solutions.

Abstract: The invention describes a process for stabilizing a leuco-dye solution in an organic solvent against oxidation in air. In the process, a compound containing at least one 2,2,6,6-tetraalkylpiperidine, 2,2-dialkylpiperidine-6-spiro-cycloalkane or piperidine-2,6-dispiro-cycloalkane grouping is added to the solution. The process is, in particular, used for stabilizing photoresist solutions which, apart from the leuco dye, contain polymerizable compounds and photoinitiators, especially radiation-sensitive trihalomethyl compounds.

Abstract: The invention comprises a photopolymerizable mixture comprising as the essential constituents a polymeric binder, a compound capable of forming a polymer by free-radical initiated polymerization, a photoinitiator, a leuco dye and a leuco dye stabilizer having at least one epoxy group. The mixture has a better shelf life in the dark than known compositions and is preferably used in the preparation of dry photoresists.

Abstract: The reaction for the preparation of 1-oxa-3,8-diaza-4-oxo-spiro[4.5]decane compounds of the formula ##STR1## proceeds more rapidly and more completely if it is performed in the presence of a phase transfer catalyst in an aromatic hydrocarbon which is liquid at room temperature.

Abstract: New polyalkyldiazaspirodecanylacetic acid derivatives are prepared by reacting diazaspirodecanes of the formula ##STR1## in which X is ##STR2## with halogenoacetic acid derivatives, and, if desired, reacting products thus obtained further with alcohols or amines. The compounds can be used as light stabilizers for plastics and lacquers.

Abstract: Polyalkyldiazaspirodecanes which are substituted in the 2-position by functional radicals and have the formula ##STR1## are prepared from polyalkylpiperidine cyanohydrins and ketones which are substituted by functional radicals.The products are suitable for stabilizing organic polymers against photo-oxidative degradation.

Abstract: Polytriazinylpiperidylamines of the general formula ##STR1## are obtained by reacting cyanuric halides with a monofunctional amino compound and a difunctional amine, it being necessary for at least the difunctional amine to be substituted by a polyalkylpiperidyl radical. The new resinous polymers have a very low volatility. They have an atactic structure and are used to stabilize synthetic polymers towards photoinduced oxidative degradation.

Abstract: Hitherto unknown polyalkylpiperidinylaminotriazines having a structure of the type ##STR1## are obtained from halogenotriazinyl compounds and aminoethylaminoethanols and can be converted into further derivatives with isocyanates, esters and acid chlorides to give new stabilizers for polymers, which stabilizers are distinguished by very good migration resistance.

Abstract: New esters and urethanes containing polyalkylpiperidylaminotriazine groups of the formula ##STR1## are prepared from carboxylic acid exters or isocyanates and triazinyl alcohols. The compounds are valuable stabilizers for polymeric materials.

Abstract: Poly-bis-triazinylimides of the formula ##STR1## are prepared from bis-(2,4-dichloro-1,3,5-triazin-6-yl)imides and polyalkylpiperidylamines.They are used as light stabilizers for polymers.

Abstract: Halogenophosphazenes of the formula ##STR1## in which n denotes 3 to 100, are reacted with alcohols or amines having polyalkylpiperidyl groups to give compounds which are suitable for stabilizing synthetic polymers and are distinguished by a very high migration resistance.

Abstract: The invention relates to new light stabilizers and heat stabilizers which have a low volatility and are migration-resistant, for use in organic polymers. They are obtained by reacting cyanuric halides with a monoamine containing piperidine groups and a polyamine component.

Abstract: Poly-bis-triazinylaminotriazinylamines are prepared from cyanuric chloride, triazinylamines and two different diamino compounds. They are light stabilizers, of low volatility and resistant to migration, for synthetic polymers.

Abstract: Diazaspirodecanes of the general formulae ##STR1## are reacted with epoxides or aldehydes to give alcohols and the latter are reacted with bifunctional compounds to form oligomers or polymers which can be used as light stabilizers for synthetic polymers. The alcohols can also be obtained if epoxy compounds which are substituted by the above diazaspirodecanes are converted into their formic acid esters and the latter are saponified.

Abstract: Triazinylaminotriazines of the general formula ##STR1## which are used as stabilizers for polymers, are prepared by reacting a cyanuric halide with amines containing triazinyl and polyalkylpiperidylamino groups.

Abstract: In the synthesis of 2,2,6,6-tetramethylpiperidone-4 (triacetone-amine) from acetone and ammonia, a partially halogenated or perhalogenated aliphatic or cyclic hydrocarbon is used as catalyst in an amount of from 0.01 to 5 mol %, relative to acetone.