DE1099166B - Sensitizers for the photopolymerization of unsaturated organic compounds - Google Patents

Description

It is known that photochemical polymerizations can be accelerated by adding sensitizers can. As sensitizers z. B. diacetyl, 2,3-pentadienone, benzyl-, phenylglyoxal, azodiisobutyronitrile, Disulfides and also mercaptans and thioethers, which are halogenated in the α-position to the sulfur atom, are used. It has also been proposed to use olefinically unsaturated compounds in the presence of N-nitrosoacyl and -aroylamines or N-nitrososulfamides as catalysts, without them being polymerized irradiate.

It has now been found that photochemical polymerizations can be carried out particularly advantageously, if N-nitrosoacylamine, N-nitrosoaroylamine or N-nitrososulfamide are used as sensitizers.

As N-nitroso compounds, which can be used, for example, as sensitizers for photochemical polymerizations suitable, may be mentioned: N-nitrosoacetanilide, N-nitrosoacetoacetic anilide, N-nitrosomethylacetamide, N-nitroso-N-butyl-n-valeroylamide, N-nitrosopyrrolidone, N-nitrosocaprolactam, N-nitroso-N-methylbenzamide, N-nitroso-N-benzylbenzamide, N-nitroso-N-benzylphenacetylamide, N-nitroso-N-butylcyanacetamide, N-nitroso-N-benzylcyanacetamide, N-nitroso-N-benzylstearoylamide, N-nitroso-N -benzyl-y-oxybutyroylamide, N-nitrosomethylurea, N-nitrosomethyl urethane, N-nitroso-N-butylbenzenesulfamide and N-nitroso-N- (2-ethylhexyl) -p-toluenesulfamide.

Such N-nitroso compounds sensitize the photopolymerization of olefinically unsaturated compounds, such as acrylic acid and methacrylic acid and their esters, vinyl acetate, vinyl propionate, styrene, a-methylstyrene, Acrylonitrile, methyl vinyl ether, cetyl vinyl ether, vinyl pyrrolidone and / or optionally mixtures such monomers. They are used in the monomers for photopolymerization in solid or dissolved form Amounts of 0.01 to 10 percent by weight, preferably 0.1 to 5 percent by weight, are added.

N-nitroso compounds of the type mentioned can be handled safely. If desired, theirs can be proportionate Good resistance can be improved by moistening with acetic acid. B. with N-nitrosocaptolactam and N-nitrosopyrrolidone is beneficial. You can also use them immediately before using them as sensitizers in a simple manner, e.g. B. by reacting the corresponding amides with sodium nitrite.

It is a particular advantage when using this readily available sensitizers that can be polymerized photochemically even at temperatures below 4O ⁰ C. When exposed to ultraviolet light or sunlight, these sensitizers break down into radicals, which then trigger the polymerization. You can therefore switch the

Sensitizers for photopolymerization
unsaturated organic compounds

Applicant:

Aniline & Soda Factory in Baden

Corporation,

Ludwigshafen / Rhine

Dr. Adolf Hrubesch, Dr. Hans Craubner

and Dr. Werner Luck, Ludwigshafen / Rhine,

have been named as inventors

Irradiation regulates the amount of radicals and thus the course of the polymerization, which is the case with block polymerizations is particularly advantageous. However, the sensitizers according to the invention can also be photochemical Polymerizations are used, which are carried out in solution, suspension or emulsion. The parts mentioned in the following examples are parts by weight.

example 1

100 parts of methyl methacrylate are mixed with 0.4 parts of N-nitrosocaprolactam and with a Mercury immersion lamp irradiated at 25 ° C. Polymerize it an average of 7% of the monomer per hour. After 3 hours, the reaction product is in 500 parts Dissolved benzene and the polymer precipitated from the solution by adding 1500 parts of light gasoline. The polymer has a molecular weight of 63,000.

Without the addition of N-nitrosocaprolactam, under otherwise identical conditions, only polymerize on average 1.9% of the monomer per hour.

Example 2

100 parts of methyl methacrylate are mixed with 2 parts of N-nitroso-N-benzyl-γ-oxybutyroylamide and irradiated with a mercury immersion lamp at 25.degree. It polymerize an average of 8 ° / ₀ of the monomers per hour. After 4 ^× _1/2 hours, the reaction product is dissolved in 500 parts of benzene and the polymer is precipitated from the solution by adding 1500 parts of gasoline. It has a molecular weight of 590,000.

Example 3

A mixture of 100 parts of methyl methacrylate and 2 parts of N-nitrosoacetoacetic anilide is mixed with

109 509/589

irradiated with a mercury immersion lamp for 5 hours at 25 ° C. It polymerize an average of 25 ° / ₀ of the monomers per hour. The reaction product is then dissolved in 500 parts of benzene and the polymer is precipitated from the solution by adding 1500 parts of gasoline. It has a molecular weight of 510,000.

Example 4

A mixture of 100 parts of acrylonitrile and 2 parts of N-nitrosoacetoacetic acid anilide is at 25 ° C with a Mercury immersion lamp irradiated. Complete conversion has occurred after 3 hours. The resulting polymer is insoluble in the monomer. Polymerize under otherwise identical conditions without adding a sensitizer on average only 0.5% of the monomer per hour.

Example 5

A solution of 2 parts of N-nitrosomethylformamide in 3 parts of chloroform is added to 100 parts of acrylic acid and the mixture is ^{irradiated with a mercury immersion lamp at 25 °} C. for 2 hours. On average, 6% of the monomer polymerize per hour. The resulting polymer is practically insoluble in the common organic solvents and has ίο the k value 94 in water at 25 ° C.

Claims (1)

Claim: Use of N-nitrosoacylamines, N-nitrosoaroylamines and N-nitrososulfamides as sensitizers for photochemical polymerizations of olefinically unsaturated compounds.