CS261085B1 - Mixed thermal and thermooxidative stabilizer and method of its preparation - Google Patents

Description

The invention relates to a mixed thermal and thermo-oxidizing stabilizer based on aralkylated diphenylamine derivatives as a process for its preparation.

Most industrially produced polymeric materials and mineral oils need the presence of certain deliberately added substances to provide the desired stability during storage and processing as well as exploitation in finished products. These substances the stabilizers retard or eventually inhibit undesirable oxidation phenomena in the substrate, so that it is not completely destroyed by oxygen, elevated UV-radiation temperature and mechanical stress.

A wide variety of antioxidant properties meet the above requirements. Among the best known and most commonly used are the group of amine antidegradants. The chemical structure of these compounds, which can be easily modified, makes it possible to obtain substances having the properties required for a wide range of the most diverse materials as well as processing and processing. exploitation conditions. Amine antidegradants are commonly used as latex stabilizers of synthetic rubbers, polyolefins, polyamides and oils, as antidegradants in latex mixtures or

X dry mixtures based on rubbers of natural and / or synthetic origin.

Examples include naphthylamines (Franta I .: Rubber raw materials, Prague, SNTL 1979), diphenylamine derivatives (e.g. OS AO 190 838), p-phenylenediamine, condensation products based on ketones and aniline, respectively. diphenylamine (Svoboda J .: Antidegradants for Rubber and Rubber, Gottwaldov 1975).

The mentioned substances have good protective properties, but their disadvantage is that they all intensely color the protected substrate, they are objections to their health (toxicity, carcinogenicity and allergic effects) - naphthylamine derivatives - PBN and p-phenylenediamine, their production is resource intensive and technologically demanding , limited availability. Moreover, they are not versatile and in many cases need to be modified before the actual application.

It has now been found that most of the above drawbacks can be overcome by using a mixed thermal and thermooxidizing stabilizer based on the aralkylated diphenylamine derivatives of the invention. The essence of the invention is that the mixed thermal and thermo-oxidizing stabilizer consists of up to 20 pens. wt. compounds of formula I

K 7 in which

^R1 is an alpha, alpha 'dimethylbenzyl, R ² is alfametylbenzyl, x and y are integers of 1 to 2 and 80 to 99 ° / o by weight. compounds of formula II

R

NH

R, (/ I) in which

R is alpha-methylbenzyl, alpha-dimethylbenzyl, z is an integer of 0.1 or 2, y is an integer of 1 or 2, and the ratio of alpha-methylbenzyl substituents to alpha, alpha-dimethylbenzyl is 1: 9 to 9: 1.

The mixture of the thermal and thermo-oxidizing stabilizers according to the invention is added to the substrate in an amount of 0.05 to 5% by weight, preferably 0.1 to 3% by weight. and can be used with other additives common to a given substrate.

Furthermore, it has been found that a mixed thermal and thermo-oxidative stabilizer can be prepared by the following process, which comprises reacting diphenylamine with a mixture of alpha-methylstyrene-styrene, at a temperature of 80 to 140 ° C, at normal pressure, catalysis in a mixture of insoluble bleaching clay catalysts, montmorillonite, aluminosilicate), wherein the diphenylamine to styrene ratio of 1: 1.3 to 3 and the alpha-methylstyrene to styrene ratio of 1: 9 to 9: 1 have also been found. unstabilized synthetic rubber latex, latex blend based on natural and / or synthetic rubbers poly-alpha-olefins, polyamides and oils.

The mixed aralkylated diphenylamine is a clear colorless to brownish viscous liquid, gradually lightly gradually turning to a reddish brown color, with low volatility, which significantly less stains the protected substrate. It is easily incorporated into the polymer substrate or oil by conventional techniques; is harmless to health, has no allergic effects.

Tahko available basic raw materials are used for its production. Own production is substantially less demanding in terms of raw materials, time, energy and overall technologists, such as in the case of p-phenylenediamine derivatives; condensation products of aniline and ketones.

Another advantage of mixed aralkylated diphenylamine is the possibility of replacing more expensive and less available p-phenylenediamine derivatives, ketone-aniline condensation products, alkylated diphenylamine derivatives (octyl-, nonyl-, ...) and the like, respectively. from the health point of view of the controversial phenyl-beta-naphthylamine, which outweighs the stabilizing effects in terms of the NH-content.

The preferred liquid form allows for easy preparation of the aqueous emulsion or solution in a suitable carrier, which is necessary for dispensing the stabilizer into the latex of natural or synthetic rubber, optionally in the latex mixture.

To facilitate the preparation of the required emulsion, suitable nonionics may be added to the subject stabilizer, optionally an anionic active emulsifier, e.g. based on alkyl polyglycol ether, respectively. alkylphenyl polyglycol ether in an amount of 3 to 10% by weight, whereby the actual stabilizer is converted into an emulsion by the addition of the necessary amount of water.

The viscosity of the stabilizer can be further adjusted by the addition of an aromatic oil conventionally used as a wetting agent in the rubber industry, preferably a mixture of mono- to tri-aromatic hydrocarbons of the Furex 433 type, with an active ingredient content of 40 to 60% by weight, e.g. for direct use in the stabilization of synthetic rubber latexes, in particular butadiene styrene.

The final form of the liquid mixed aralkylated diphenylamine can also be treated by adsorption to an inert inorganic carrier, with an active ingredient content of 40 to 70 washings. by weight to obtain a powdered powdered product suitable for lightweight weighing and dosing into dry rubber compositions, polyamides, polyolefins, and the like, where no liquid product dispensing device is available.

These examples illustrate but do not limit the invention. .

Example 1

Place in a 500 ml four-necked flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser.

169.23 g (1 mol) of diphenylamine. Heat the contents of the flask to 70 ° C and add 35.8 g of bleaching earth with stirring. The temperature of the reaction mixture was raised to 100 ° C and 189 g of a mixture consisting of 88.53 g (0.85 mol of styrene and 100.5 grams (0.85 mol of alpha-methylstyrene) were added with stirring over 3 h. the reaction mixture was kept at 100-105 ° C for 3 hours. the crude reaction was finalized by filtration. the kinematic viscosity of the product at 60 ^q C: 610 mm ² / s.

The following proportions of aralkylated diphenylamine derivatives were found by chromatography:

WITH

8.8% w / w:

4-alpha-methylbenzyl, 4‘-alpha, alis‘-dimethylbenzyl-diphenylamine

45.6 wt.

mixtures of mono (2-, and 4-) and di (2,4- and 4,4 4,4-) alphamethylbenzyldiphenylamine

45.6% by weight:

mixtures of mono (4) and di (4,4‘-) alpha, alpha‘-dimethylbenzyldiphenylamine

Yield: 336.8 g (94%).

Example 2

The procedure of Example 1 is as follows:

169.23 g (1 mol) of diphenylamine

39.2 g (bleaching earth)

104.2 g g (1 mol) styrene

118.2 g (1 mol) of alpha-methylstyrene.

The crude reaction mixture is finalized by filtration followed by mixing with a wetting agent into rubber campaigns based on a mixture of predominantly mono-, di- and tri-aromatic hydrocarbons (Furex 433) in a ratio of 1: 1. Kinematic, viscosity of Furex treated stabilizer at 50 ° C: 428 mm ² / sec.

Composition of a mixture of aralkylated diphenylamine:

% by weight:

Mixtures of 4-alpha-methylbenzyl, 4‘-alpha-alpha-dimethylbenzyl- and 2,4-di-alpha-methylbenzyl, 4‘-alpha, alpha‘-dimethylbenzyldiphenylamine% by weight:

% of a mixture of mono (4-) and di (4,4‘-) alpha, alpha‘-dimethylbenzyldiphenylamine

mixtures of mono (2- and 4-), di (2,4- and 4,4‘-) and tri (2,4,4‘-alpha-methylbenzyldiphenylamine), Yield: 376 g (96%).

Example 3

The procedure is as in Example 1 of the following weights

169.23 g (1 mol) of diphenylamine

35.8 g bleaching clay

37.8 g (0.36 mol) styrene

151.2 g (1.28 mol) of alpha-methylstyrene. Chromatography determined:

4.3 wt.

4-alpha-methylbenzyl, 4‘-alpha, alpha‘-dimethylbenzyldiphenylamine

21.0% wt.

mixtures of mono- (2- and 4-) and di- (2,4- and 4,4 ‘) alphamethylbenzyl diphenylamine

74.7 wt.

mixtures of mono (4-) and di- (4,4 ‘-) alpha, alpha‘-dimethylbenzyldiphenylamine

The crude reaction mixture was finalized by filtration followed by mixing with a plasticizer (Example 2) (1: 1).

Kinematic viscosity of the plasticized product at 50 ° C: 556 mm ² / s. Yield: 340 g (95%).

Example 4

The procedure of Example 1 is as follows:

169.23 g (1 mol) of diphenylamine

39.1 g bleaching clay

177.9 g (1.7 mol.) Of styrene

44.5 g (0.38) alpha-methylstyrene

The crude reaction mixture was finalized by filtration. The viscosity of the filtrate at 50 ° C is 483 mm ² / / q / s.

Composition of the reaction mixture:

2.7 wt.

4-alpha-methylbenzyl, 4‘-alpha, alpha‘-dimethylbenzyldiphenylamine

79.9% wt.

mixtures of mono- (2- and 4-), di- (2,4- and 4,4 4,4) and tri- (2,4,4‘-) alpha-amylbenzyldiphenylamine

17.4 wt.

Mixtures of mono- (4-) and di- (4,4 ‘-) alpha, alpha‘-dimethylbenzyldiphenylamine

Yield, 364 g (93%).

Example 5

The mixed thermal and thermo-oxidizing stabilizer of the invention prepared according to Example 1 (Stabifizer 1), is in the form of a toluene solution at a concentration of 1.0 wt. to dry matter in the usual manner dosed into cream of butadiene-styrene latex type 1500 used for production of Kralex 010.401 rubber. After coagulation and drying of the obtained rubber, the stabilizing efficiency of the subject stabilizer was monitored by thermo-oxidative loading of the raw rubber in a forced air 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 - 4 ‘/ 100 ° C rubber, which is caused by oxidation at higher temperatures.

Table 1

Stabilization of aralkylated or diphenylamine in Kralex 010 401, 130 ° C

Stabilizer Viscosity MQONEY ° ML 1 - 4 '/ 100 ⁰ hours of stress

0 1 2 4 6 8 difference 0 58.5 58.5 68.5 74.9 74.5 76.0 +22.5 stabilizer 1 50.0 45.0 43.0 44.5 49.0 91.0 + 1.0 % phenyl-beta-naphthylamine, 1.5 wt. 49.0 55.0 54.0 51.5 51.0 33.0 + 4.0 % mixed diphenyl-p-phenylene diamine, 0.75 wt. 51.0 54.0 54.0 51.0 53.0 50.5 - 0,5

The stabilizing efficiency of the subject stabilizer is at the level of the stabilizing efficiency of the available stabilizers used at their normal dosage levels.

Example 6

Mixed thermal and thermo-oxidizing stabilizer according to the invention, prepared according to example 4 (Stabilizer 2). Treated on an inorganic carrier of hydrated SiO ₂ type, containing 60% active ingredient and added (3.0 parts by weight of active ingredient per 100 parts by weight of rubber) to a mixture based on Neoprene GS chloroprene rubber, containing HAF soot and the ZnO (ethylenethiourea) tetramethylliuram disulfide vulcanization system.

In the case of vulcanizates prepared by pressing of the raw mixture into the optimum, the following values of heated physico-mechanical properties were achieved after accelerated thermo-oxidative aging according to ČSN 621 511 at 130 degrees Celsius for 1 to 7 days:

Table 2

Properties of CR rubber vulcanizates, 160 ° C

parameter 0 Stabilizer 2 2,2,4-trimethyl-l, 2-i hydroxyquinoline residual 2 days 59 65 52 ductility (%) 3 days 42 55 36 4 days 30 49 29 5 days 6 40 21 7 days 6 18 10 dynamic fatigue according to de Mattia - crack formation, kc original 5.8 12.9 10.8

In the case of chloroprene rubber, the ductility (the so-called critical variable) is the property that changes most significantly during aging. The subject stabilizer exhibits the highest stabilizing stiffness.

EXAMPLE 7 The nylamine of Example 2 (Stabilizer) was dosed in a conventional manner at a concentration of 1.5% by weight on the active ingredient into the butadiene-styrene rubber latex type 1712. Further procedure as in Example 1.

Stabilizer based on aralkylated dife261035

Table 3

Stabilization of stabilizers in Kralex 011.403 at 130 ° C

Stabilizer used: Mooney viscosity, ° ML 1-47100 ° C loading time, hr.

0 1 2 4 6 8 Stabilizer 3 50.5 44.0 36.0 22.5 19.5 19.0 fenylbetanaftylamín 1.5 wt. 49.0 38.5 37.5 22.0 18.5 18.0 mixed diphenyl-p-phenylenediamine 0.75 wt. 50.5 38.0 35.0 19.0 17.0 15.5

The stabilizing efficacy of the present stability of the available stabilizers used in the lyser is at the level of the stabilizing effective dosage levels.

Claims (2)

OBJECT OF THE INVENTION A miscible thermal and thermo-oxidative stabilizer based on aralkylated diphenylamine derivatives, characterized in that it comprises 1 to 20 wt. the compounds of formula (I) Λ NI in which R ¹ is alpha, alpha'-dimethylbenzyl, R ² is alpha-methylbenzyl, x and y are integers 1 to 2 and 80 to 99% by weight; compounds of formula II wherein: R is allylmethylbenzyl. and α, α-dimethylbenzyl, γ is as defined above, z is an integer of 0, 1 or 2 and the ratio of α-α-methylbenzyl substituents to α, α-dimethylbenzylin is 1: 9 already 9: 1. 2. A process for preparing a mixed stabilizer according to claim 1, wherein the diphenylamine is reacted with an alphamethylstyrene: styrene mixture at a temperature of 80 to 140 degrees Celsius, under normal pressure and in the presence of a mixture of insoluble catalysts containing bleaching clay, montmorillonite and aluminosilicate. the ratio of diphenylamine to styrene mixture is 1 _: 1.3 to 3, and the ratio of alpha-methyl-styrone: to styrene is 1: 9 to 9: 1.