CS272364B1 - Method of mixed netting agent preparation for polymer materials - Google Patents

Abstract

Polymeric crosslinking agent with a mixture of 10-99.5% by weight of 2,4,6-trimercapto-1,3,5-triazine and 90 to 0.5 wt 2 (R) -4,6-dimercapto-1,3,5-triazine (R is hydroxyl or R, 'R', N, wherein R'a R "is alkyl, hydroxyalkyl or cyclohexyl with a total number of carbons 1 to 8) by reacting cyanuric chloride in an aqueous suspension with an aqueous solution of sulfide or acid sulfide sodium and further by reaction with an aqueous solution alkali hydroxide or equivalent primary or secondary amine. The ratio of substances in the mixture is solved using calculated the number of reacting components.

Description

The invention relates to the preparation of a mixed crosslinking agent consisting of 10 to 99.5% by weight. 2,4,6-trimercapto-1,3,5-triazine and 90% to 0.5% by weight. dimercapto-1,3,5-triazine substituted in position 2 by a hydroxyl group or alkyl, dialkyl, alkoxy or thialkoxyamine groups. The composition is intended for crosslinking certain polymers and copolymers, especially polyvinyl chloride, chlorinated or chlorosulfonated polyethylene, polypropylene and some synthetic rubbers.

Modification of polyvinyl chloride by crosslinking is a known method for altering the properties of this polymer. An improvement in a number of properties can be expected from the crosslinked modified polymer. Modification by crosslinking increases, for example, hardness, tensile strength, heat resistance, thermal dimensional stability, resistance to solvents, hot water and weathering.

Polyvinyl chloride chains can be chemically crosslinked by the direct action of crosslinking agents on the polymer chains, or by the crosslinking reaction of incorporated comonomers in the polymer chain or side chains introduced into the PVC macromolecule by a grafting reaction. The same applies not only to PVC, but also to other types of said polymers.

One of the methods for direct crosslinking of PVC polymer has been described as the use of substituted triazine compounds, of which 4,6-dimercapto-s-triazines substituted further in item 2 have been shown to be highly effective non-degradative crosslinkers. The rate of crosslinking depends on the substitution of the triazine core, but achieving the highest crosslinking rate is not the desired optimum, as is the degree of crosslinking, as different crosslinking rates and degrees of crosslinking can affect certain predetermined properties of the resulting polymer that are required.

Until now, crosslinking agents have been prepared as a single chemical individual, and for their own application, according to the required physical properties of the product, their regulation has been carried out by dosing them by changing their amount or by changing their type or using a mixture of crosslinking agents. There are several disadvantages to this approach. It is a problem with binding and mixing of two, sometimes more components, not each of which is always available, there is not always a guarantee for the same composition of the mixture and thus the same effect. The preparation of the components themselves in the form of pure substances is relatively difficult. Although trimercaptotriazine of the formula I can be prepared by several patented processes using sodium sulfide and cyanuric chloride in an aqueous medium without great technological demands, substituted dimercapto-1,3,5-triazines of the formula II are very difficult to prepare in the pure state by reactions in heterogeneous phases and solvents ( eg Czechoslovak Patent No. 156 446/1973) in a multistage synthesis, the intermediates having to be purified by vacuum rectification.

It has now been found that difficulties in the preparation and application of these substances are eliminated by the use of a mixed crosslinking agent prepared by the process of this invention. In this way, a mixed crosslinking agent containing 10 to 99.5% by weight can be prepared. 2,4,6-

-trimercaptotriazine of formula I

SH SH i a and 90 to 0.5 wt. dimercapto-1,3,5-triazine substituted in position 2 of formula II, wherein R is hydroxyl or a group R, 'RN, in which R' and R is alkyl, hydroxyalkyl or cyclohexyl with a total number of carbons of 1 to 8, one of substituents, R 'or R' may be hydrogen.

CS 272364 Bl

The ratio of substances in the mixture can be determined in advance using the calculated amounts of reactants. The preparation method consists in reacting a suspension of cyanuric chloride in water with a theoretically calculated amount of an aqueous solution of sulfide or sodium hydrogen sulfide, the reaction being completed by adding the appropriate primary or secondary-amine of formula R'R NH, where R 'and R are as defined above. alkali hydroxide at a temperature of 60 to 100 ° C and the product is isolated by acidifying the reaction mixture with a mineral acid.

A practical embodiment consists in first preparing a suspension of cyanuric chloride in water in the reactor by adding a suitable wetting agent to the mixture of water and ice and adding the required amount of cyanuric chloride with stirring at a temperature of up to 5 ° C. Then, a pre-prepared solution of sulfide or acid sulfide is slowly admitted into this suspension so that no major hydrogen sulfide leaks occur and the mixture is not overheated locally. It is advisable to keep the reaction temperature as low as possible, especially initially, so that the final product contains as few by-products as possible from the hydrolysis of unreacted cyanuric chloride with water. A much less suitable process, especially from an ecological point of view, is the process of forming an initial suspension or even a solution by dissolving cyanuric chloride in acetone. After adding all the calculated amount of solution and checking the end of the reaction of cyanuric chloride with sulfide, the required amount of primary or secondary amine or alkali hydroxide is added to the reactor, and the reaction is completed by brief heating to 60-100 ° C depending on the amine used. It is advisable to keep the reaction mixture in solution throughout the reaction, because in the case of a heterogeneous mixture, the reaction will be greatly slowed down. Therefore, if an aqueous solution of sodium bisulfite is used, the addition of an equivalent amount of alkali, whether in the form of alkali carbonate or alkali hydroxide in the form of lye, must be used to keep the intermediates in solution. The use of alkali carbonate is more advantageous because the pH of the reaction solution does not rise too high, so that the final product does not contain a large amount of by-products derived from the competitive hydrolysis of cyanuric chloride.

After completion of the reaction, the product is precipitated from the mixture by acidification with mineral acid (preferably to a pH value in the range from 3.5 to 4.5) and the precipitated product is filtered off with suction and washed with water. If necessary, the dried substance is adjusted by grinding to the desired particle size.

Condensation products of fatty acids with amino acids or amines, alkyl polyglycols, tert, dialkyl sulfosuccinates, condensation products of enphthalene sulfoic acids with formaldehyde or condensation products of fatty acids with ethylene oxide can be used as wetting agents.

The advantage of this mixed sulfurizing agent lies in its ease of preparation and simplicity of its application. For a given purpose, the sulfurizing agent can be easily and economically produced in large quantities, its constant composition is guaranteed, mechanical operations such as weighing, mixing, etc. are eliminated during the actual application.

The following examples describe the performance of syntheses of some mixed sulfurizing agents. The examples given are by weight.

Example 1

100 parts of water are introduced into the reactor, to which 0.5 parts of Slovasol 0 (wetting agent) are added and, after stirring is started, 25 parts of cyanuric chloride are introduced. A solution of 35.3 parts of technical sodium sulfide containing 75% of active substance in 100 parts of water is added to this mixture over a period of 30 minutes, maintaining a temperature of up to 30 ° C. After all the sulfide solution has been added, the temperature is raised to 60 DEG C., 6.65 parts of cyclohexylamine are added dropwise and the mixture is heated to 90 DEG C. and maintained at this temperature for a total of 3 hours. The reaction mixture is then cooled to 50 [deg.] C., the mixture is quenched with kane, hydrochloric acid for a positive reaction to Congo red and the precipitated product is filtered off while still hot. The product cake is washed on the filter with water until acidity is lost and dried in a hazelnut oven at 110 ° C. Yield of a product with a composition of 50% of 2-cyclohexylamino-4,6-dimercapto-1,3,5-triazine (formula I, R = cyclohexylamino) and 50% of 2.4,

6-trimercaptotriazine (I, R = SH) is 28 parts, which corresponds to about 85% of theory.

Example 2

100 parts of cold water are introduced into the reactor, to which 0.5 parts of Spolion 8 are added and, after starting the stirring, 25 parts of cyanuric chloride are introduced. Meanwhile, a solution of sodium sulphide is prepared by pouring into 150 parts of water a solution of technical acid sodium sulphide containing 400 g of NaHS / l and 122 g of NagS / l in an amount of 54 parts (h = 1,250) and dissolving 10.5 parts of sodium carbonate. The solution thus prepared is added to the present cyanuric chloride suspension under cooling over a period of 2 hours so that the temperature does not exceed 40 ° C. After all the sulfide solution has been added, the reaction mixture is stirred for a further 2 hours, then 0.9 parts of monoethanolamine are added and the reaction solution is heated to 90 DEG C. for 1 hour and maintained at this temperature for 1 hour. After completion of the reaction, the reaction solution is cooled to 60 DEG C., acidified by adding 50X sulfuric acid to give a positive reaction to Congo red, and the precipitated product is filtered off with suction while hot and washed thoroughly with water on the filter. A dried product consisting of 10% 2-hydroxy ethylamino-4,6-dimercapto-1,3,5-triazine and 90 X 2,4,6-trimercapto-1,3,5-triazine as a pale yellow non-melting powder was obtained in a yield of 17.6 parts, which corresponds to about 73% of theory.

Example 3

80 parts of water are introduced into the reactor, to which 0.5 parts of nonionic wetting agent are added and, after stirring is started, 25 parts of cyanuric chloride are added. Meanwhile, a solution of 30.5 parts of technical sodium sulfide at a concentration of 78% of active substance in 120 parts of water is prepared, which is then added to the cyanuric chloride suspension over a period of 1 hour at 40 ° C. The solution is stirred at this temperature for a further 2 hours, then 4.1 parts of solid sodium hydroxide are added and the solution is heated to 95 ° C. It is maintained at this temperature until the reaction is complete (pyridine test), then the reaction mixture is cooled to 50 [deg.] C. and acidified to pH 3.5-4.5 by the addition of dilute sulfuric acid. The precipitated yellow product is filtered off with suction, washed on the filter with water and dried at 110 [deg.] C. A product of about 25% 2-hydroxy-4,6-dimercapto-1,3,5-triazine and 75% 2,4,6-trimercapto-1,3,5-triazine was obtained in a yield of 18.1 parts. which corresponds to about 77 X theory. (Analysis was performed using standards and thin layer chromatography).

Claims (2)

OBJECT OF THE INVENTION Process for the preparation of a mixed crosslinking agent for polymeric materials consisting of 10 to 99.5% by weight. 2,4,6-trimercapto-13,5-triazine of formula I XH (I), and 90 to 0.5% by weight of dimercapto-1,3,5-triazine substituted in position 2 of formula II (II), wherein R is hydroxyl or a group R 'and R ¹ , ¹ N-, wherein R' and R are acrylic, hydroxyalkyl or cyclohexyl having a total number of carbons of 1 to 8, wherein one of the substituents R 'or R 1 may be hydrogen, characterized in that a suspension of cyanuric chloride in water is reacted with a calculated amount of sulfide or sodium bisulfite in aqueous solution and, after completion of the reaction, an aqueous solution containing a calculated amount of alkali hydroxide or primary or secondary amine of formula III is added. R'R NH (III), where R'and R are as defined above, at a temperature of 60 to 100 ° C and the product is isolated by acidifying the reaction mixture with a mineral acid.