DE1543178C - Process for the production of polyisocyanates with a biuret structure - Google Patents

Description

3 4

The polyisocyanates with a biuret structure are converted into valuable 3-pentanol. Implementation starts at

Starting materials for the production and modification 95 ⁰ C, as the development of carbon dioxide shows. Man

from plastics after isocyanate polyaddition, a liquid polyisocyanate with a biuret structure is obtained,

Process, especially for the production of lightfast which is practically free of solids.

Lacquer coatings. . . , 5. .

Example 1 Example 3

In a procedure according to Example 1 with a heating jacket, thermometer and cooler, parts by weight of concentrated sulfuric acid are added to the reaction components by weight of 0.001 Ge-dry ice-acetone cold trap equipped with a sodium hydroxide-asbestos absorber and the reaction components mentioned there. 100 parts by weight of hexamethylene The reaction vessel ¹⁰ begins at 7O ⁰ C as the Kohlendioxidcyanat and 5 parts by weight of tert-butyl alcohol shows overall development. The polyisocyanate obtained is also mixed. The temperature is raised and the biuret structure corresponds to the isocyanate from Example 1. slowly. At 150 ⁰ C the development of coal. .
dioxide observed. At 195 to 200 ⁰ C is shown lively ι s ρ ι e 1 4
sticky reaction. In the cold trap, a ¹⁵ in one with a heating mantle, thermometer and liquid with a hydrocarbon-like odor forms. It cooler with a sodium hydroxide asbestos absorber is isobutane. The temperature in the reaction vessel equipped with the reaction vessel and dry ice / acetone cold trap is maintained at 200 to 205 ° C. for 60 minutes, 100 parts by weight of hexamethylene are then cooled. Unreacted hexa-diisocyanate, 100 parts by weight of triethylene glycol diacetate methylene diisocyanate is ^{mixed with the polyiso-ao formed} and 15 parts by weight of tert-butyl alcohol, cyanate with a biuret structure is heated by distillation and the temperature is allowed to rise slowly, separated. 28.4 parts by weight of a liquid biuret triisocyanate, free of solids, begins at about 145 ° C. as back dioxide. At 195 to 200 ⁰ C there is a lively level in the distillation vessel. Amine equivalent 197.1; Reaction. The temperature is kept at the reaction NCO content of 21.3%. * ⁵ jar at 200 to 205 ° C for one hour and then cool. away. The solution obtained can be used directly as a solution in Example 2 of a polyisocyanate with a biuret structure.

In the procedure according to Example 1 you can also by distilling off the solvent

1,2-Di- (isocyanatomethyl) -cyclobutane and 3-methyl- are concentrated under reduced pressure.

Claims (5)

1 2 vinyl diisocyanate, aliphatic claims containing ether groups: table diisocyanates such as 1,3-bis- {y-isocyanatopropoxy) - 2,2-dimethylpropane, 1,3-bis - (}> - isocyanatopropoxy) - 1. Process for the preparation of polyisocyanates 2-methyl-2-propylpropane, 1-methyl-2,4-diisocyanatomite Biuret structure, characterized by 5 cyclohexane, 1-methyl-2,6-diisocyanatocyclohexane, net that you have at least 2.5 moles of an aliphatic bis ^ Isocyanatocylohexyty-methane, 1,4-diisocyanatotic or cycloaliphatic diisocyanate with cyclohexane and!, S-diisocyanatocyclohexane. 1 mol of a monohydric tertiary alcohol in the case of monohydric tertiary alcohols are examples Temperatures of at least 70 ⁰ C converts. to name wisely: tert-butyl alcohol, 2-methyl-2-buta- 2. The method according to claim 1, characterized in that the reaction is carried out at 150 to S-ethyl-3-pentanoI, S-ethyl S-nonanoI, 3-methyl-205 ⁰ C carries out. l-butyn-3-ol, S-methyl-l-pentyn-S-ol, 3,5-dimethyl- 3. The method according to claim 2, characterized in l-hexyne-3-oil, l-methylcyclopentanol, 1-methylcyclograph, that at least 3 moles of a diiso- hexanol, 1-ethylcyclohexanol, 1,1-diphenylethanol, Reacts cyanate with 1 mole of alcohol. 15 1,1,2-triphenyl ethanol. : 4. The method according to claim 1 to 3, characterized in that Preferred diisocyanates are: hexamethylene diisocyanates, that the reaction with cyanate, the isomer mixture of l-methyl-2,4-diiso-hexamethylene diisocyanate, the isomer mixture cyanato-cyclohexane and l-methyl ^ ö-diisocyanato from 1-methyl-2,4-diisocyanatocyclohexane and cyclohexane, and bis- (4-isocyanato-cyclohexyl) -mel-methyl-jo-diisocyanatocyclohexane or with up to 30 than. The preferred alcohol is tert-butyl alcohol. (4-Isocyanatocyclohexyl) methane carries out. There are at least 2.5 moles of the Diisocyanats.mit 5. The method according to claim 1 to 4, characterized in that 1 mole of alcohol is reacted. It is preferred to have at least that you use the reaction with at least 3 moles of diisocyanate. An optimal one tert-butyl alcohol carries out. Result is achieved with 9 moles of diisocyanate 35 used very high excess of diisocyanate, so it may be desirable not to be implemented Diisocyanate from the process product by distillation or extraction, whereby it is Polyisocyanates with a biuret structure are known. refuses to keep temperatures too high for long periods of time They are obtained by reacting aromatic poly-30 uses. A thin film evaporator or a Isocyanate with water or hydrogen sulfide via rapid evaporator is recommended. Will not the intermediate stages of a urea diisocyanate, used in a substantial excess of diisocyanate, see above which is further diisocyanate via the hydrogen, a separation is not necessary as it is at all Atoms of the urea groups are deposited. This may be desirable to combine the polyisocyanate with biuret drive have the disadvantage that there is an undesirable structure mixed with monomers! Diisocyanate Form solids that leave the equipment clogged. and their regular shutdown and cleaning The temperature for the requirements according to the invention, settlement must be at least 70 ° C. A preferred The subject of the invention is an improved temperature range between 150 and 205 ^° C. Process for the preparation of polyisocyanates with 40 The polyisocyanates obtained with a biuret structure Biuret structure which eliminate these disadvantages have the general formula
allowed. The procedure is characterized by that at least 2.5 moles of an aliphatic or an O cycloaliphatic diisocyanate with 1 mol of an Il (jf | Trihydric tertiary alcohol at temperatures of 45 O C - NH - R - NCO at least 70 ⁰ C are implemented. Il I The reaction takes place via the formation of an OCN R NH C N R NCO unsaturated hydrocarbon, the development
of carbon dioxide and via the non-isolated intermediate stages of a urea diisocyanate, from which the polyisocyanate with a biuret structure is then formed in the R denotes the aliphatic or cycloaliphatic. Means the remainder of the diisocyanate. If the temperature is surprisingly no solids occur. exceeded of 205 ⁰ C, so the excess can The unsaturated hydrocarbons can be used as the diisocyanate with the hydrogen atoms of the condensed by-product biuret and the formed structure to higher functional isocyanates react, carbon dioxide can be connected to suitable means such. B. Sodium 55 which is generally absorbed because of the formation of solids hydroxide-asbestos preparation. Which is not wanted. The amount of carbon dioxide developed gives an indication The use of catalysts is generally about the progress of the reaction. The procedural base is not necessary. To speed up the product remains in the reaction vessel without a reaction, such as boron trifluoride, sulfuric acid, disruptive formation of solids. 60 phosphoric acid, phosphorous acid, hydrochloric acid or Suitable aliphatic or cycloaliphatic diiso- aluminum trichloride in question. Cyanates as starting materials are e.g .: Ethylidene- The reaction is generally carried out in the melt diisocyanate; Butylene diisocyanate, pentamethylene diisocyanate, but can also be carried out in inert solution jyanate, hexamethylene diisocyanate, 1,3-cyclopentylene agents such as dioxane, tetrahydrofuran, triethylene Jiisocyanat, 1 ^ cyclohexylene diisocyanate, 1,2-cyclo- 65 glycol diacetate, toluene, benzene, chlorobenzene, o-di- lexylene diisocyanate, hexahydroxylylene diisocyanate, dichlorobenzene, butyl acetate, ethylene glycol monoethyl : Chlorhexamethylene diisocyanate, 4,4'-dicyclohexyldi- ether acetate or methylene chloride made socyanate, 1,2-di- (isocyanatomethyl) -cyclobutane, trans- become.