DE1222926B - Protect organic substances against UV radiation - Google Patents

Description

Protecting organic substances against UV radiation Numerous organic Compounds have the property of electromagnetic radiation in the area absorbing from 2900 to 3700 Å, and if they are in various plastic materials, For example, transparent films are incorporated, the film obtained acts like a filter for the incoming light and only lets through the rays that are not absorbed by the film and / or the absorbent. That's the way it is possible to screen out undesirable radiations and the transparent film obtained to use as a filter for many technical and economic purposes, for example for packing food or the like.

There are already numerous organic compounds as absorbents proposed for the radiation range described, referred to as the ultraviolet range been. Their intended use includes incorporation in plastic films and generally the stabilization of transparent plastic bodies. By far that the most important of all ultraviolet radiation is that of the sun. Most of these rays have wavelengths between 250 and 400 millimicrons. The effect of this radiation on human skin, which causes sunburn and tan, is natural known.

Another economically important factor is that from ultraviolet radiation caused photochemical decomposition. Lots of off-the-shelf products are out there, though exposed to such radiations either become impermanent or so extensive impaired that they are unusable and unsaleable.

Many plastic materials learn when subjected to this radiation considerable degradation, thereby developing undesirable color bodies and the transparency is decreased. Food often discolor and are also often inedible. So are fruits, food oils, and butter other prepared foods go bad and rancid if left in ultraviolet for a long time Exposed to light. It is also known that colored objects, such as colored Textiles that are faded by sunlight, especially ultraviolet light. Many plastics not only form color compounds and become more opaque, they also become brittle, lose their elasticity, tear and decompose finally in the sunlight completely. Paints, varnishes and varnishes are also available exposed to these effects, although in this case the transparency is not so is essential.

It was found that by incorporation of a-cyano-B, 8-diphenylaryl derivatives obtained in a large number of film-forming plastics, resins, waxes materials are having good ultraviolet absorbing properties in the general in question coming ultraviolet range of 250 to 400 millimicrons. The connections, used in the mixtures and methods of the invention not only very good absorption properties near the visible range of the electromagnetic Field, but are also essentially colorless compounds in which guaranteed is that in normal way colorless materials produce no color and also not the color of colored materials, such as colored film or colored ones Textiles. Many in the blends and methods of the invention The compounds used also absorb part of the visible light on the violet End of the spectrum, which makes them particularly suitable for preparations that are used for protection of visible light decomposable products. This includes known polyester and polyethylene, in which the compounds according to the invention proved extremely successful as a stabilizer.

The compounds to be used according to the invention are also particular useful as they do not have to contain a phenolic hydroxyl group in order to be lightfast to surrender. The hydroxybenzophenones previously used as absorbents own such a group. The presence of a salt-forming phenolic hydroxyl group makes these absorbents for use in alkaline media and especially unsuitable in basic plastics such as melamines.

However, the compounds to be used can also contain hydroxyl groups if the compounds to be protected do not contain any basic groups.

It is therefore the purpose of the invention to propose new UV protection agents, contained as such or in a transparent film, organic compounds give improved protection against degradation by ultraviolet radiation.

The present invention therefore relates to the use of organic compounds of the general formula which do not contain nitro groups in which (Ar) 1 and (Ar) 2 aromatic carbocyclic, optionally substituted nuclei free of kera-bonded amino groups, and Z yYi - OY or - N residues Y2 mean, where dY, Y1 and Y2 are hydrogen atoms or organic radicals or their oxyalkylation products, for protecting organic substances against UV radiation.

Preferably (Ar) 1 and (Ar) 2 represent phenyl groups or substituted phenyl groups, so that the more detailed formula 1 of the formula corresponds, where Z is as defined above and X1 and X2 are a low molecular weight alkyl group, halogen, a hydroxy or low molecular weight alkoxy group or aryl radicals.

In the above formulas, the substituents Y, Y1 and Y2 except hydrogen, alkyl (C1-C8), alkenyl (C3-C4), cyanoalkyl (up to 18 carbon atoms in the alkyl group), hydroxyalkyl (up to 18 carbon atoms in the alkyl group), Carbalkoxy-alkyl (up to 4 carbon atoms in the alkoxy or alkyl group), Haloalkyl (up to 12 carbon atoms in the alkyl group), alkoxyalkyl (up to to 12 carbon atoms in the alkyl group), polyhydroxyalkyls, e.g. B. glyceryl, heterocyclic radicals, such as tetrahydrofurfuryl, aryl radicals, phenol ether, hydroxyalkylaryl, Chlorine, bromine, nitro, carboxy, carbalkoxy, acylaryl, acylalkylamino, acylamino or sulfamylphenyl derivatives.

In addition to the above-mentioned derivatives, according to the invention, their polyoxyalkylated derivatives can be used. Each of the derivatives mentioned, the at least Contains a reactive hydrogen atom, can with an alkylene oxide or a as an oxide acting compound, such as ethylene oxide, propylene oxide, butylene oxide, butylene dioxide, Cyclohexane oxide, glycid, epichlorohydrin, butadiene dioxide, isobutylene oxide or styrene oxide implemented.

Several different alkylene oxide groups can also be introduced into the molecule. Examples of such compounds can be characterized by the following general formulas: where R is H, alkyl, aryl or (XO) aH and R1 is (XO) bH, where X is the radical introduced by the alkylene oxide and a and b are the number of these radicals introduced.

If X1 and / or X2 are hydroxyl groups in formula II, then their polyoxyalkylation products are also suitable according to the invention, with a total of 30 moles of ethylene oxide per mole of a-cyano, ß-di- (4-hydroxyphenyl) - acrylic acid amide used can be.

The compounds used according to the invention are, depending on their type and are soluble in many solvents, plastics, synthetic resins and waxes therefore particularly suitable for stabilizing organic substances. They don't Oxyalkylated products are insoluble in water. Compounds that have smaller quantities contain on oxyalkyl groups, d. H. up to about 4 to 6 groups per molecule generally soluble in polar organic solvents and readily in water dispersible.

The compounds that contain a large number of alkylene oxide groups d. H. over about 6 moles per mole of the reactive hydrogen containing compound, are soluble to highly soluble in water, the solubility increasing with the The number of oxyalkyl groups increases.

To achieve the claimed effect, the one to be stabilized Incorporate only the required amount of stabilizer into the material.

In general, between 0.1 and 10 percent by weight is sufficient, preferably between about 0.5 and 2 percent by weight, based on the organic to be stabilized Material. As already mentioned above, the ultraviolet used according to the invention Absorbents are not only used to stabilize clear films or plastics will; they are also suitable for use in opaque, semi-transparent or translucent Materials whose surface is affected by ultraviolet Light is damaged. The different types of materials include foamed ones Plastics, opaque foils and coatings, opaque types of paper, translucent and opaque fibers, transparent and opaque colored plastics, fluorescent pigments, polishes, creams or lotions, whether they are opaque, clear or translucent. The ones used according to the invention Connections provide paints, enamels, and lacquer and varnish coatings excellent Protection against fading of the pigments and dyes it contains. The most essential However, the improvement brought about by the invention lies in the protection of polyoxymethylene and compositions containing nitrocellulose against deterioration by ultraviolet Light. It was found that those used in the blends of the present invention Stabilization compounds are at least five times more effective than before Hydroxybenzophenones used for these purposes.

It has also been found that those used according to the invention Compounds excellent for use in transparent and translucent Base layers for the various types of pressure sensitive products commonly used today Adhesive tapes are suitable. By using these compounds on the above In the area, the duration of the adhesive strength of the pressure sensitive adhesive becomes essential elevated. The compounds can not only be incorporated directly into the carrier, they can also be used in a film coating that acts as a film former contains any material adhering to the back of the carrier. For example the back of a regenerated cellulose tape with one of those in the examples 1 and 2 described cellulosic paints are coated. For direct incorporation Any compound described is suitable in regenerated cellulose; particularly suitable however, the alkylene oxide adducts are those containing at least one reactive H atom Basic connections, e.g. B. the compounds according to Example 13.

In this case, the regenerated cellulose is preferably still as Gel impregnated before final drying.

The following examples serve to illustrate the invention.

Example 1 Ultraviolet Stabilization of Nitrocellulose Film One Mixture of 20 parts of solution A and 80 parts of solution B, the solution being A from 46 parts of nitrocellulose (1/2 sec), 4 parts of o - cyano - ß, ß - diphenylacrylic acid ethyl ester, 35 parts of a non-drying, plasticizing alkyl resin, 15 parts of dibutyl phthalate and solution B of 35 parts of butyl acetate, 15 parts of butanol, 50 parts of toluene duration, became one by means of a conventional spreader on a metal plate Film pulled out with a thickness of 0.075mm. A similar movie was made in the same Way by pulling out a lacquer mixture in which, however, the 4 parts of a-cyano-ß, fl-diphenylacrylic acid ethyl ester replaced by 4 parts of nitrocellulose (1/2 sec).

After 100 hours of exposure the developed without the a-cyano-ß, ß-diphenylacrylic acid ethyl ester produced film a distinctly yellow color, while that of the ultraviolet absorbent containing film remained colorless after a 100 hour fadeometer exposure. Will the experiment with the corresponding tetrahydrofurfuryl ester (that = 36 at 303 ml) repeated, similar results are obtained.

Example 2 Stabilization of cellulose acetate films or those packaged therein Food 0.375 g a - cyan - fl, fl - (4 - chlorophenyl) - acrylic acid ethyl ester, 3.5 g ethanol, 6.5 g ethylene glycol monomethyl ether, 9.0 g ethyl acetate, 26 g cellulose acetate varnish, which consisted of 3.75 g of cellulose acetate in 21 g of acetone were mixed with stirring, until a clear solution was obtained. The solution was poured into a mold and the solvent evaporated to give a 3 mm thick casting. A similar casting was made in the same way, but with the a-cyano, ß- (4-chlorophenyl) -acrylic acid ethyl ester was omitted. That the ultraviolet Material containing absorbent showed in the case of the foodstuffs packaged therein, z. B. meat, a better light stability than that without the ultraviolet absorbent.

The acrylic acid ester used is prepared as follows. The production the UV protection agents to be used according to the invention are not claimed.

In one with a stirrer, a thermometer, a reflux condenser, A 500 cc flask fitted with a water trap and heating mantle became the following Charge added: 28.25 g of ethyl cyanoacetate (0.25 mole), 62.75 g of 4,4'-dichlorobenzophenone (0.25 mole), 3.85 g ammonium acetate, 12 cc glacial acetic acid, and 75 cc benzene.

The feed was stirred at reflux for 12 hours, whereupon the benzene is distilled off and the residue is diluted with 150ccm water and was filtered. The lumps were broken up and the solids in 100 cc of water Slurried and filtered, whereupon the cake on the funnel with 200 cc of water washed and the product air dried. Then the product distilled at a pressure of 2.5 mm and a temperature of 185 to 200 "C.

The 16 g of the material was made from 150 cc of ethanol and 300 cc of water recrystallized after being treated with activated charcoal and filtered.

M.p. = 81 ° C.

EXAMPLE 3 Stabilization of polyethylene films or meat packaged therein A mixture of 99.5 g of polyethylene and 0.5 ga-cyano, B-phenyl, B- (4-n-dodecyloxyphenyl) -acrylic acid ethyl ester was fused to a solution at 120 "C.

The material then became a film about 0.75 thick mm pressed out. Meat that contains the ultraviolet absorbent Film was packaged showed lower levels after exposure to ultraviolet light Discoloration as meat that is in a similar slide without the absorbent was packed.

The manufacture of the UV absorber used that is not claimed was carried out as follows: 300 cc of n-butyl alcohol and 4.0 g of sodium hydroxide spheres (0.1 mole) were mixed together and then 19.8 g (0.1 mole) of 4-hydroxybenzophenone first and then 44.2 g (0.15 mol) of 1-iodo-n-dodecane were added. The loading was then stirred for 15 hours at a temperature of 680 C, then to room temperature cooled and diluted to a volume of 1 l with methanol. Subsequently were 0.6 g of sodium hydroxide was added to render the material phenolphthalein alkaline. The material was then filtered to give 4- (n-dodecyl) oxybenzophenone. This was, as described in Example 2, condensed with ethyl cyanoacetate, wherein however, instead of the dihalobenzophenone used in this example, 0.25 mol 4- (n-dodecyl) oxybenzophenone were used.

Example 4 Stabilization of polyester films or those packaged therein Textiles 1.0 g of a-cyano-β- (2-chlorophenyl) -p- (4-chlorophenyl) -acrylate methyl ester in 100g of a polyester resin made from 300/0 styrene and 700/0 glyceryl phthalate maleate, which contained 10 / o of an organic peroxide dispersed with a filler, dissolved. Between opal glass plates treated with a silicone mold release agent a casting was made. The sealing material was between the Plates placed and clamped together. Then the polyester was in the Mold poured and cured as follows: The initial oven temperature was 65 "C, and this was then slowly increased to 90 ° C. and at this temperature for 1 hour maintain.

The temperature was then increased to 1200C and this 1/2 hour maintained to complete curing. Thereupon the material on the cut to desired size. The polyester produced in this way offers better protection against sunlight in clothes exhibited under his protection are, as a material produced in a similar manner, but without the use of the ultraviolet absorbent.

Example 5 Stabilization of leather The following mixture became a leather care emulsion prepared: 160 g methyl acrylate, 16 g butyl acrylate, 1.7 g a-cyano-ß-phenyl-ß- (4-methoxyphenyl) acrylate ethyl ester (prepared accordingly the method according to Example 2), 20 g dispersant (alkylaryl polyether sulfonate), 0.3 g ammonium persulfate, 176 g water.

The mixture was shaken until it became uniform milk white emulsion resulted. The emulsion was thereupon within 21/2 hours gradually poured into 500ccm of water and then refluxed for 3 hours. That The product obtained was then sprayed onto leather, which was then placed between panels pressed and dried. The leather treated in this way and the one applied Coatings were less prone to yellowing than when non-ultraviolet coatings were used Absorbent.

Example 6 Stabilization of leather a-cyano-A, -di (p-tolyl) -acrylic acid ethyl ester was incorporated into a synthetic rubber compound in the following manner: Off the above-mentioned ultraviolet absorbent was made by kneading for several hours of 20 g of the compound with 20 g of formaldehyde naphthalene-2-sodium sulfonate in one Werner Pfleiderer mixer in the presence of an amount of water sufficient to generate the To give the material a viscous consistency, a 500% dispersion is prepared.

The material was then evaporated to dryness, creating the absorbent was obtained in dispersed form. Then the dispersed absorbent incorporated into an acrylonitrile butadiene latex, with 50/0 absorbent, based on based on the weight of the latex used. The latex was then sprayed onto leather, and the film produced in this way was less prone to sagging upon exposure Yellowing as a similar film made in the same way but without the use of the ultraviolet absorbent. Even the leather was through the film effectively protected against UV rays.

Example 7 Stabilization of a polyvinyl chloride foam Es was a 50% solution of a-cyano-ß, ß-diphenylacrylic acid ester in methyl ether of sithylene glycol. In this solution was a sponge immersed in polyvinyl chloride foam.

The sponge was then removed from the solution by squeezing it out freed from the remaining solvent and dried in vacuo. That on material impregnated in this way with the ultraviolet absorbent is against more resistant to ultraviolet light than untreated material.

Example 8 Stabilization of a polyurethane foam a 50% solution of a-cyano-di (4-hydroxyphenyl) -acrylic acid ethyl ester in sithylene glycol monomethyl ether and dipped a polyurethane sponge into this solution. Then was Remove the sponge from the solution by squeezing out the remaining solvent freed and dried in a vacuum oven. The impregnated material tipped exposure to ultraviolet light is less likely to yellow than an untreated one Material.

Example 9 Stabilization of cellulose acetate 4-phenylbenzophenone was condensed with ethyl cyanoacetate according to Example 2, the a-Cyanoß - phenyl - fl - (4-biphenyl) - ethyl acrylate was obtained. This connection was as the compound according to Example 2 applied in cellulose acetate, excellent Protective properties for substances packed in it showed.

Example 10 Stabilization of colored paper on glossy paper a lacquer layer was made of 2% of the dye: anthranilic acid o 4-sulfophenylmethylpyrazolone, Chromium, dicyclohexylamine salt and 2 0 / o a - cyan - fl - phenyl - - (4 - methoxyphenyl) - Acrylic acid ethyl ester applied in nitrocellulose, this was used for comparison Repeat the process, but using a nitrocellulose lacquer mixture, which contained 20/0 of said dye, but no ultraviolet absorber. After 500 hours of exposure to the fadeometer, it showed the ultraviolet absorbent lacquer containing significantly less yellowing.

Example 11 Stabilization of cellulose acetate films or those packaged therein Food a - cyano - ß, ß-diphenylacrylic acid amide was wrapped in a cellulose acetate film incorporated according to Example 2 and resulted in films through which the foodstuffs packaged therein, z. B. Meat, and other articles showed increased lightfastness.

The same results were obtained with a-cyano-ß, ß-diphenylacrylic acid-N, N-dimethylamide achieved.

Example 12 Stabilization of an Epoxy Resin A mixture was made from 2 parts of an epoxy resin made from alkylenebisphenol and epichlorohydrin, 1 part m-phenylenediamine and - based on the total polymer - 5 percent by weight of a-cyano, p - diphenylacrylic acid - N, N - dimethylamide produced. The material was thereupon for 24 hours Heat solidified in a mold at 120 "C. This product showed on exposure less color change with ultraviolet light than a material that is based on similarly, but without the absorbent being heat solidified.

Example 13 Stabilization of Cellulose-Containing Products Ein by Addition of 6 moles of ethylene oxide to the stabilizer described in Example 8 obtained Product (Kmax = 21 at 344 mm dispersed easily in water and could be used for treatment of paper or other cellulose-containing products, for example cotton or Jute, can be used. This polyoxyalkylated product is also an excellent one Dispersant for pigments and dyes and provides when used with these materials provide excellent protection against degradation by ultraviolet rays Light.

The adduct containing 20 moles of ethylene oxide has excellent properties Surface properties and can be used to produce emulsion of the El-in-water or. Water-in-ul type can be used. Such emulsions are anti-impairment well protected by ultraviolet light.

The adduct of a-cyano-phenyl-fl- (2-sulfaemylphenyl) -acrylic acid ethyl ester, which contains 9 moles of propylene oxide, is likewise water and oil soluble as well as surface active.

The manufacture of the UV absorbers does not fall under the present invention Invention.

With a similar stabilizer that has only 2 ethylene oxide groups instead of 6 similar results were obtained.

Example 14 Stabilization of formaldehyde polymers Polyoxymethylene was mixed with 1 percent by weight of a-cyano - p, p - diphenylacrylic acid ethyl ester and produced from them films at 190 to 200 "C and a pressure of 140 kg / cm2. Films were also produced without the UV absorbent.

The foils produced in this way were exposed to a "weatherometer" after 30 days it was found that the film with the stabilizer was practical was unchanged; there was no impairment, such as B. cracks or scratches, to be determined on the surface. However, the unstabilized film showed considerable cracks and scratches. Larger ones can also be used without adverse consequences Amounts of stabilizer can be obtained.

Similar results were obtained with a - Cyanp, fl - (4 - chlorophenyl) - ethyl acrylate, a - cyano - (2-chlorophenyl) - fl - (4-chlorophenyl) - methyl acrylate and a-cyano-ß, ß-bis (4-hydroxyphenyl) acrylic acid ethyl ester achieved.

The improvement in the stability of the polyoxymethylene described above is in view of the fact that there are many other ultraviolet absorbers proved to be completely ineffective in such connections, regarded as remarkable. It is important that the invention used as a stabilizer Compounds can also be used during the polymerization of formaldehyde and do not adversely affect the course of the polymerization.

Claims (3)

Claims: 1. Use of organic compounds of the general formula which are free of nitro groups. in which (Ar) 1 and (Ar) 2 aromatic carbocyclic, optionally substituted nuclei free of nucleus-bound amino groups, and Z jYl OY or N \ residues N \ yRSt mean, where Y, Y1 and Y2 are hydrogen atoms, organic radicals or their oxyalkylation products, for protecting organic substances against UV radiation. 2. Embodiment according to claim 1, characterized in that about 0.1 to 10 weight percent UV absorber based on the weight of the organic Substance, can be used. 3. Use of with a compound of the general formula des Claim 1, in which (Ar) l and (Ar), benzene nuclei and Z denote an alkoxy group, in particular from α-cyano, ß-diphenylacrylic acid ethyl ester, finished nitrocellulose according to claim 1 as a transparent protective film or lacquer. Documents considered: German Auslegeschrift No. 1,021,981.