SK278615B6 - Method for preparation of the liquid concentrate for stabilizing polymeric materials - Google Patents

Abstract

The concentrate containing 30 up to 70 weight percent of mixture closed to the compounds with a general formula (I), where the symbols R1 and R2 are of the same meaning or of the different one and they mean alpha methyl benzyl or alpha dimethylbenzyl, the symbol x means integer in a value of 0 up to 2 and the symbol y means integer in a value of 0 up to 3 and this mixture is soluble in 70 up to 30 % of softener, while this softener consists of the mixture closed to aromatic and/or naphthenic hydrocarbons, is being prepared based on the alyklation of diphenylamine with styrene or with the mixture of styrene and alpha methyl styrene, at the temperature of 80 up to 120 Celsius degrees, while bleaching clay is present and acting as the catalyst, however the ration of diphenylamine and styrene is 1 : 1,5 up to 2,0. Water contained in the product, carried in that process by the used bleaching clay, however this product is created as a result of the reaction mixture filtration, is removed with the use of vacuum distillation, and the filtration cake is prepared which consists of the part closed to the reaction product and of the used catalyst, this cake is washed at the temperature of 80 up to 180 Celsius degrees, at the pressure of 2,5 up to 40 kPa, with the use of softener in a multiply excess (3 up to 8) related to the reaction product quantity contained in the filtration cake, and the such colature is mixed with the above mentioned isolated reaction product and softener, while water was removed of this cake before this mixing started. Water carried in this process also can be removed with the use of the vacuum distillation closed the starting the starting consisting of diphenylamine and bleaching clay, before feeding of styrene is started and the rest of water can be removed based on the distillation closed to the resulted reaction mixture, while the used catalyst can be removed of it. The liquid concentrate is applied to stabilise polymers, related to caoutchouc family especially, to prevent the thermic or thermo-oxidising degradation.

Description

Technical field

The invention relates to a process for the preparation of a liquid concentrate for stabilizing polymeric materials, in particular rubbers against thermal and thermo-oxidative degradation, based on aralkylated diphenylamines and an aromatic plasticizer.

The various derivatives of diphenylamine and p-phenylenediamine represent a group of important and widely used stabilizers of polymeric materials, especially rubbers. Because of the relatively high viscosity, they are often used in the form of oil solutions.

BACKGROUND OF THE INVENTION

Prior art processes for the preparation of alkylated diphenylamine derivatives are based on the alkylation of diphenylamine with olefins, for example diisobutene (US 3,714,258), styrene or alpha-methylstyrene (US 2,943,112) with catalysis of BF ₃ etherate, H ₂ SO ₄ , p-toluenesulfenoic acid, AlCl 3. (US 2,943,112, US 3,714,257, US 3,714,258, US 2,017,253). Their disadvantage is that, in addition to the various isomers of alkyl-substituted diphenylamines, a considerable amount of unreacted diphenylamine remains in the reaction mixture. This can be removed by demanding high-temperature fractional distillation, respectively. low vacuum. Commercial technical products contain up to 10% by weight of free diphenylamine. When applied in the rubber industry, under the conditions of processing of rubber mixtures at temperatures above 100 ° C, it becomes volatile, which results in not only air pollution in the working areas, but in fact also lower dosing of the anti-degradant. This, in turn, results in less effective protection of the polymeric materials against degradation effects. A further drawback of the known processes for the preparation of alkyl-substituted diphenylamines is that after the alkylation process is completed, the alkylation catalyst used must be scrubbed. Accordingly, the process is mostly conducted in organic solvents from which the catalysts are then washed with water. This results in a considerable amount of waste water, which can only be disposed of by demanding procedures. The high degree of reaction of the starting diphenylamine with the corresponding olefin and the simple isolation of the alkylation catalyst used from the resulting reaction mixture provides the process of CS 191 570, which operates with a mixture of insoluble catalysts such as bleaching clay impregnated with polyphosphoric acid. Its significant disadvantage is that a significant portion of the end product (9-15%) remains sorbed onto the filtered catalyst, resulting in considerable economic losses.

SUMMARY OF THE INVENTION

The diphenylamine derivatives as well as the p-phenylenediamine derivatives produced in this way are advantageous to be converted into oil solutions due to their relatively high viscosity, but this is associated with the construction of a warehouse management system including reservoirs, pipelines, pumps and scoops. oil. Said components are maintained at the necessary processing viscosity by heating. The actual mixing of the oil and the stabilizer requires additional equipment - tank with stirrer and heating and measuring cup with pump. It has now been found that most of the above drawbacks are overcome by the process for preparing a liquid concentrate for stabilizing 5 polymeric materials, especially rubbers, against thermal and thermooxidative degradation containing 30 to 70% by weight of a mixture of aryl alkylated diphenylamines of formula (I).

d) wherein R ¹ and R ² are the same or different and are alpha-methylbenzyl or alpha, alpha-dimethylbenzyl, x is an integer from 0 to 2 and y is an integer from 1 to 3 soluble in 70 to 30% by weight of a plasticizer consisting of mixtures of aromatic and / or naphthenic hydrocarbons, alkylation of diphenylamine with styrene or a mixture of styrene and alpha-methylstyrene at a temperature of 80 to

120 ° C, in the presence of bleaching clay as a catalyst and at a molar ratio of diphenylamine to styrene of 1: 1.5 to 2.0 according to the invention. SUMMARY OF THE INVENTION After filtering the resulting reaction mixture, the filtrate consisting of the reaction product is freed from the water introduced into the process using bleached clay vacuum distillation, the filter cake consisting of part of the reaction product and the catalyst used is washed at 80 to 120 ° C and with a 3 to 8-fold excess of plasticizer, calculated on the reaction product content of the filter cake, and the filtrate thus obtained is mixed with the water-free reaction product already isolated and the plasticizer.

It has also been found to be advantageous to remove the bulk of the water introduced into the bleaching clay process by vacuum distillation of the initial diphenylamine / bleaching clay mixture prior to the start of the styrene or styrene / alpha-methylstyrene mixture and remove the residual water by vacuum distilling the resulting reaction mixture. thus saving pumping operations in particular.

For example, a plasticizer based on a mixture of predominantly mono-, di- and tri-aromatic hydrocarbons (Furex 433), a mixture of aromatic and naphthenic hydrocarbons (Triumf), or based on a mixture of naphthenic hydrocarbons, may be used as the plasticizer having the function of a solvent. Washing the filter cake with a plasticizer will reduce the content of the reaction product to be adsorbed to the alkylation catalyst used to a minimum (1-2%).

A decisive advantage of the process according to the invention over the known processes for the production of similar products is that it conveniently combines the isolation of the technical product from the resulting reaction mixture with its treatment into an oil concentrate in one operation, which means a reduction in investment costs of approximately 50%. and laboriousness. The considerable elimination of losses on the technical product due to its sorption to the alkylation catalyst used significantly improves not only the economic but also the environmental characteristics of the process. The liquid concentrate prepared by the process of the present invention is a low viscous brown viscous liquid with a low dustiness, a very low coloring polymer substrate. It is harmless to health and its production is considerably less demanding in terms of raw materials, energy and technology than in the case of naphthylamine and p-phenylene derivatives2.

-diamine. In addition, its oil component sets an adequate amount of rubber hydrocarbon, thereby reducing the cost per unit amount of rubber produced, respectively. it replaces a commonly used plasticizer (a proportion thereof) in a rubber composition. The liquid form of the concentrate allows the use of an automatic dosing system and subsequent immediate incorporation, for example, into the prepared unstabilized latex without prior treatment.

The liquid concentrate prepared by the process according to the invention is distinguished by its versatility for all common types of synthetic rubber latexes (butadiene-styrene, isoprene, butadiene and butadiene-acrylonitrile), respectively. rubber mixtures. It is added to the polymer substrate in an amount of 0.5 to 5.0% by weight, preferably 1 to 3% by weight, and can be used together with other additives suitable for the substrate, to which it is incorporated by conventional processing techniques as other additives.

Examples:

The following examples illustrate but do not limit the scope of the invention.

Example 1

To a 600 L reactor equipped with a stirrer, reflux condenser, thermometer and measuring cup was charged 215.5 kg (1.27 kmol) of diphenylamine and allowed to melt. At 75 ° C the stirrer is switched on and 44 kg of bleaching clay (catalyst) are metered in. The reaction mixture is heated to 95 ° C and styrene is metered in at a rate such that the reaction temperature is between 98 and 105 ° C. After the addition of 225.5 kg (2.16 kmol), the reaction mixture was further stirred for 3 h and then filtered on a pressure filter. 397 kg (90%) of filtrate are obtained, from which excess water is removed by vacuum distillation. Filter cake containing 50 wt. (44 kg) of the aralkylated diphenylamine mixture is washed with 285 kg of Furex 433 aromatic softener at 80 ° C and at a pressure of 2.5 to 10 kPa. The filtered oil solution of the substituted diphenylamine mixture in an amount of 168 kg containing 23 wt. acc. % of the component and 77 wt. The oil is mixed with the undiluted product and made up by adding an appropriate amount of aromatic oil to a concentration of 50% by weight. active ingredient. The liquid concentrate is characterized by: viscosity kinematic at 50 ° C = 293 mm ² / s,% N = 2.21.

Example 2

The procedure is as in Example 1 from the same batches. 369 kg of filtrate (84% by weight) were obtained from which water was distilled off. The filter cake containing 62% by weight (72 kg) of the mixture of aralkylated diphenylamines is washed at 110 ° C at a pressure of 30 to 40 kPa with 504 kg of Furon 433 armonate softener. % of the oil is further mixed with the isolated reaction product and finalized by adding an appropriate amount of aromatic oil to a concentration of 40% of the active ingredient. The liquid concentrate is characterized by: viscosity kinematic, 50 ° C = 224 mm ² / s,% N = 1.64.

Example 3

A 4-necked flask equipped with a stirrer, reflux condenser, thermometer and dropping funnel was charged with 169.23 g (1 mol) of diphenylamine and heated to 75 ° C. After thawing, 39.2 bleaching earth is added, mixed, the temperature is raised to 100 ° C and 104.2 g (1 mol) of styrene and 118.2 g (1 mol) of alphamethylstyrene are added. After filtering off the catalyst, 359.0 g of an active ingredient filtrate are obtained, from which water is distilled off. The filter cake containing 44% by weight of the active ingredient - a mixture of aralkylated diphenylamines, is washed at 100 ° C at a pressure of 3 to 6 kPa with five times the Triumf type aromatic-naphthenic plasticizer. Further processing according to Examples 1 and 2. The product is finalized to a concentration of 70% by weight of the mixture of aralkylated diphenylamines. The liquid concentrate is characterized by: viscosity kinematic at 50 ° C = 485 mm ² / s,% N = 2.52.

Example 4

The liquid concentrate prepared according to Example 1 (stabilizer 1) was added to the dry solids of rubber at a concentration of 2.2% by weight (i.e. 1.1% of active ingredient) to the dry solids of butadiene-styrene rubber of type 1,500. After coagulation and drying the obtained rubber by monitoring the stabilizing efficiency of the subject stabilizer by thermo-oxidative loading of the raw rubber in an air circulation oven at 130 ° C for 0 to 8 hours. The measure of the stabilizing efficiency is always the change in the viscosity of MOONEY ° ML 1 - 47100 ° C rubber, which occurs due to degradation processes during oxidation at higher temperatures. The measured values are in Table 1.

Oabult · 2

StabillUtor (> hMtnoBtao) 0 Utolltl uoarsx M1 - 4/100 ° 0 8 h 1 2 4 6 - 53,0 66.0 77.0 82.0 64.0 SteMlieátol * 1 47.5 51.0 51.5 53.5 55.0 54.0 f-jl.-hyi-tr * - tjrlarfft -1.6.5 49.5 55.0 54.0 51.0 50.0 »5 (smm / Oi-fejyl- + UMMtl9k4 MKfc- Barriers 1 and 2) - 51.0 54.0 54.0 51.5 53.5 50.0

The stabilizing activity of the subject stabilizer with respect to the active ingredient content exceeds that of the phenyl-beta-naphthylamine as well as the p-phenylenediamine derivative with two functional groups, calculated on the concentration of the -NH group in the stabilizer.

Example 5

The liquid concentrate for the thermal and thermo-oxidative stabilization of the polymeric materials of the invention, prepared according to Example 2 (Stabilizer 2), was applied to the dry solids of rubber at a concentration of 2.5% by weight (i.e. 1.0% of active ingredient) to the creamed latex of butadiene-styrene rubber. Type 1 712. Further procedure according to Example 4. MOONEY ML-4/100 ° C viscosity values are given in Table 2.

TatelTk · 3

SteMl teater U heetnortaU) 0 žlakoalta B0 «r híl, - 4/100“ N 1 2 4 6 8 h Stablll ether 2 46.0 44.0 43.0 36.5 24.5 21.0 ftayUtetMeftrl- to 2.0 and 44.0 36.5 34.5 20.0 13.0 11.0 (re-di-phenylP-fMrtáMUou + Et ametieká eeftk- 46,5 S «ved ·, 1 i 2) · - 2.4 S • n, o 38.0 2 »> 0 19.0 17.5

II I

The stabilizing efficacy of the subject stabilizer exceeds the stabilizing efficacy of the known amine stabilizers, in terms of the concentration of -NH groups in the stabilizer.

Example 6

The liquid concentrate prepared according to Example 3 (Stabilizer 3), at a concentration of 3.6% by weight (2.5% per active ingredient), calculated on rubber, was added to the GS based chloroprene rubber composition containing the carbon black, HAF type, aromatic plasticizer , stearic acid and a crosslinking system consisting of a combination of MgO / ZnO / tetramethylthiurane disulfide / ethylene thiourea.

For vulcanizates prepared by pressing the raw mixture to the optimum at 160 ° C, the following values of selected physico-mechanical properties were achieved after accelerated thermo-oxidative aging according to ČSN 02 1511 at 130 ° C for 1 to 7 days, the critical quantity ( aging) is the difficulty.

íatuCIu J

i-aramter dipped diphangrleain Lteblllsátor 3 1, 2,1-triethyl-1,2,2-dihydro- srjíkwá J dM 55 6 t> 65 M 3 dol 42 51 % 35 4 days 30 42 48 17 5 da £ 6 35 41 * 13 7 days - 15 20 1 J dyneeiekí ´íixeva {Faint Uattia (rsalk t »hl_ £ a) to and 12.5 1 4.6

comprising a mixture of aromatic and / or naphthenic hydrocarbons, alkylation of diphenylamine with styrene or a mixture of styrene and alpha-methylstyrene at a temperature of 80 to 120 ° C, in the presence of a bleaching clay catalyst and 5 at a molar ratio of diphenylamine and styrene of Characterized in that the resulting reaction mixture is filtered, the filtrate consisting of the reaction product is freed from the water introduced into the process using the bleached clay by vacuum distillation, 10 the filter cake consisting of part of the reaction product and the catalyst used is washed at a temperature of 80 to 120 ° C and a pressure of 2.5 to 40 kPa with a 3- to 8-fold excess of plasticizer, calculated on the reaction product content of the filter cake, and the filtrate thus obtained is mixed with the already isolated water-free reaction product and plasticizer.

2. The process of claim 1 wherein the bulk of the water introduced into the bleaching clay process is removed by vacuum desillation of the initial diphenylamine / bleaching earth mixture prior to the start of styrene / alpha-methylstyrene and the rest of the water is added. It is removed by vacuum distillation of the resultant reaction mixture or the catalyst used.

End of document

The subject stabilizer exhibits the highest stabilizing effect.

Example 7

Using the same starting material weights and the same equipment as in Example 1. From the mixture of molten diphenylamine and bleached clay heated to 95 ° C, the bulk of the water introduced into the bleaching clay process was removed by vacuum distillation prior to dosing. Example 1. The resulting reaction mixture was freed of residual water by vacuum distillation and filtered on a pressure filter to give 394 kg (89%) of the reaction product, which was further worked up analogously to Example 1.

Claims (1)

PATENT CLAIMS Process for the preparation of a liquid concentrate for stabilizing polymeric materials, in particular rubbers, against thermal and thermo-oxidative degradation, comprising 30 to 70% by weight of a mixture of aralkylated diphenylamines of the general formula (I), (d) where R ¹ and R ² are the same or different and are alpha-methylbenzyl or alpha, alpha-dimethylybenzyl, x is an integer from 0 to 2 and y is an integer from 0 to 3 dissolved in 70 to 30% by weight of a plasticizer