DD149231A1 - STABILIZERS FOR HIGH POLYMERS, LOW-MOLECULAR ORGANIC COMPOUNDS AND OILS - Google Patents

Abstract

Stabilizers for high polymers, low molecular weight organic compounds and oils against degradation by oxidation and heat. It was intended to increase the stability of organic materials in their manufacture and use. This involves the use of stabilizers with high efficacy and high intrinsic stability. As stabilizers, pyrazoles of the general formula are added to the substrates during processing or during the production of molding materials. The stabilizers work in a wide temperature range (273 to 473 K). They are used in a concentration of 0.01 to 1% by mass and are suitable for the stabilization of e.g. Polyethylene, ethylene copolymers, polyvinyl chloride, oils, tetralin.

Description

-Ί-

VEB Leuna-Werke - Merseburg, d. 21. 12, 1979

."Walter Ulbricht"

LP 79115 Title of the invention

Stabilizers for high polymers, low molecular weight organic compounds and oils

Field of application of the invention

The invention relates to inhibitors for stabilizing high polymers, low molecular weight organic compounds and oils against degradation by oxidation and heat.

Characteristic of the known technical solutions

The stabilizing effect of some pyrazole compounds in polymers is known. For example, it is known that diaminopyrazoles act as oxidation inhibitors in polyethylene, ethylene-vinyl acetate copolymers, polyvinyl chloride etchers and in hydrocarbons such as paraffin oil and tetralin (DD-PS 114 612) known to stabilize, polypropylene, polyethylene and other polymers with metal-complexed pyrazoles against degradation by light and oxidation (DD-PS 111 396) _e In addition, the use of triaryl is known or ·, trialkyl-substituted pyrazoles against the degradation of polyvinyl chloride plasticized with plasticizers by Light and heat. (US Pat. No. 2,946,765).

- <> -. r; n ·; η π η, Γ · /.

The mentioned pyrazole derivatives have the disadvantage that they discolor the organic compounds to be protected either during incorporation, especially at high temperature or later higher thermal and / or oxidative continuous load, which limits their technical usefulness

Object of the invention

The aim of the invention is to improve the thermal and the thermo-oxidative stability of high polymers !! and low molecular weight organic compounds and oils,

Explanation of the invention of the invention

The object of the invention is to develop substances which cause both an increase in the thermal and the thermo-oxidative stability of organic compounds at low and very high temperatures. This object is achieved by stabilizers for high polymers, low molecular weight organic compounds and oils against degradation by oxidation and heat from the group of pyrazoles, according to the invention in particular pyrazoles of the general formula

in which R ₁ and R _{4 are the} same or different, optionally substituted radicals, wherein R and R, Alley I, cycloalkyl, aralkyl, aryl or heterocyclic radicals, R _{2 is} an unsubstituted or monosubstituted to polysubstituted aniline radical R 1 is hydrogen, alkyl, cycloalkyl, aryl, aralkyl, optionally substituted,

R- and R are optionally also closed to form a ring, are used as inhibitors,

Pyrazole derivatives which are particularly suitable as stabilizers,

1-phenyl-3-anilino-5-phenyl-pyrazole

- 1 ~ phenyl-3 - (pH ethylanilino) -5-phenyl-pyrazole

- 1 ~ (p-bromophenyl) -3- (pHethylanilino) -5-phenyl-pyrazole

- 1- (p-Methoxyphenyl) -3-anilino-5-phenyl-p.vazole

- 1- (p -tolyl) -3-anilino-5-phenyl-pyrazole

τ 1-Phenyl-3 - (p-chloroanilino) -5- (p -methoxyphenyl) pyrazole ~ 1-phenyl-3- (p-hydroxyanilino) -5- (p-tolyl) pyrazole

- 1- (p-1-iitrophenyl) -3-anilino-5-phenyl-pyrazole

The abovementioned alkyl-aryl-substituted 3-anilino-pyrazole compounds can also be used in combination with other stabilizers or plastic additives, such as quenchers, complexing agents, lubricants, UV absorbers and antistatic agents. Advantageously, the pyrazoles in a concentration of 0.01 to 1 percent by mass, in particular from 0.1 to 0.5 percent by mass, based on the amount of substrate and the known additives, in a concentration of 0.01 to 0.6 percent by mass, in particular of 0.05 to 0.3 percent by weight, based on the amount of substrate used. The amount of stabilizer to be added depends on the structure of the organic compounds to be stabilized. Thus, a stabilizer content of 0.01 to 0.3 percent by mass is required to stabilize polyolefins. To stabilize oils and low molecular weight organic compounds, 0.1 to T mass percent stabilizer has been found to be effective.

The incorporation of the stabilizers in the plastic without or with further additives is advantageously carried out in the processing phase to the molding material at the usual or elevated processing temperatures. In the stabilization of oils or low molecular weight organic compounds, the pyrazoles are either dissolved in these substances, suspended ^] or mixed with them »

The particular effect of the stabilizers according to the invention is that they give the high molecular weight and low molecular weight organic compounds a higher stability even at elevated temperature under the action of oxygen and are characterized by higher color stability than the known amino stabilizers *

 embodiments

In the tables, the following abbreviations are used for the stabilizers according to the invention:

1-phenyl-3-anilino-5-phenylpyrazole = A

1 ~ (p-ITitrophenyl) -3 ~ anilino ~ 5-phenyl-pyrazole = B 1-phenyl-3 - (p -methylanilino) ~ 5-phenyl-pyrazole = C

1 ~ (p-Methoxyphenyl) -3-anilino-5-phenylpyrazole = D

Purely the known stabilizers use the following abbreviations:

4.4 ^l -Thio bis (3-methyl-6-tert-butylphenol) = U

3- (p ~ Metho: c / anilino) -5-amino-pyrazol-carbonaäure-

(4) ethyl ester = V

2, 2 ^l- methylene-bis- (4-methyl-6-ct-niethyl-

cyclohexylphenol) = W

Phenyl-β-naphthylamine = X-

Phenyl-O-C-naphthylamine _ γ

example 1

0.2% by mass of 1-phenyl-3-anilino-5-phenyl-pyrazole (A) or, 1 ~ (p-nitrophenyl) -3-anilino-5-phenyl-pyrazole (B) are mixed in polyethylene. The mixture is processed at 383 K within 10 minutes on a rolling mill to 0.25 mm thick films. The color stability of the polymer films is assessed visually after aging in an air atmosphere at 423 K _e The following table shows the comparison to samples without stabilizer and with known stabilizers (U, V) »

, polyethylene

without stabilizer

Color of the foil

With A With B With U With V Example 2

after production

colorless colorless colorless colorless almost colorless

after 48 hrs. Aging in air at 423K

strong yellow colorless colorless almost colorless faint brown

0.2% by mass of 1-phenyl-3-anilino-5-pentenyl-pyrazole (A) or 1-phenyl-3- (p-methylanilino) -5-phenyl-pyrazole (C) at 383 K within 10 minutes mixed in polyethylene on a rolling mill. The mixture is then pressed under a pressure of 30. MPa to 0.03 mm thick films »The oxidation stability of the film samples is tested at 446 K in pure oxygen. The table shows the oxygen absorption compared to the film sample without stabilizer and with known stabilizers (U, V),

Absorption of 2 mmol oxygen / g PE after min

23

180

434

148

polyethylene Beginning d admission without stabilizer 8th with A 85 with C 62 with U 75 with V 22 Example 3

In an ethylene-vinyl acetate copolymer, 0.2 percent by mass of 1-phenyl-3-anilino-5-phenyl-pyrazole (A) or «. 1 ~ phenyl-3- (p

methylanilino) -5-phenyl-pyrazole (C). At 323 K on a rolling mill, the mixture becomes O at 10 minutes _? 25 mm thick films "The table shows the result of the visual evaluation of the film after aging in an air atmosphere at 423 K in comparison to the polysilicon without stabilizer and with known stabilizers (W, V),

 Ethylene-vinyl acetate copolymer The color of the film

after production after 48 hours »

Aging in the air at. 423 K

without stabilizer colorless strongly yellow

with A colorless colorless

with C colorless colorless

with W colorless almost colorless

with V colorless almost colorless

Example 4

0.2% by mass of 1-phenyl-3-anilino-5-phenyl-p: yrazole (A) or 1-phenyl-3- (p-methylanilino) -5-phenyl-pyrazole (C) are within 223 K within 10 minutes mixed in 'an ethylene-vinyl acetate copolymer. The. Mixture is then pressed under a pressure of 30 MPa to 0.05 mm thick films. The oxidation stability of the film samples is tested at 346 K in pure oxygen. The table shows the result in comparison to samples without stabilizer and with known stabilizers (W, V).

"Se ™ *

Ethylene-vinyl acetate beginning of the oxygen uptake of 1 mmol Copolyineres stoffaufnähme after oxygen / g after

min. , min

without stabilizer 6 17

with A 52 472

with C 60 516

with W 80 242

with V 55 360

Example 5.

0.01 m mol of 1-phenyl-3-anilino-5-phenyl-pyrazole (A) or 1-phenyl-3- (p-methylanilino) -5-phenyl-pyrazole (C) or 1- (p- Methoxyphenyl) -3-anilino-5-phenyl-pyrazole (D) and 0.2 moles of azoisobutyronitrile as an initiator are dissolved in 20 ml of tetralin, the solution is stirred at 333 K and an oxygen partial pressure of 0.1 MPa. The table shows the oxygen uptake in comparison to samples without stabilizer and with known stabilizers (X, U),

Tetralin + time [min]

Azoisobutyronitrile until the uptake of acid by

10 ml

without stabilizer 35 ·

with A 280

with C 380

with D 340

with X 255.

with U 210

Example 6

Commercially available purified paraffin oil (white oil) containing 0.05 mass% of azoisobutyronitrile as an initiator and 0.2 mass% of 1-phenyl-3-anilino-5-phenyl-pyrazole (A) is disclosed in U.S.Pat

The table shows the induction period compared to samples without stabilizer and with known stabilizer (Y),

Paraffin oil + induction period [. Min

Azoisobutyronitrile.

without stabilizer none

with Y 240

with A 430

Claims (3)

- 3 ".1 Invention claim 1. Stabilizers for high polymers, low molecular weight organic compounds and oils against degradation by oxidation and heat ', from the group of the pyrazoles, characterized in that in particular pyrazoles of the general formula, in which R ₁ and R are identical or different, optionally substituted radicals, wherein R ₁ and R are alkyl, cycloalkyl, aralkyl, aryl or heterocyclic radicals, Rp is an unsubstituted or a mono- to polysubstituted aniline radical is, R is hydrogen, alkyl, cycloalkyl, aralkyl, aryl radical which is optionally substituted iert, R ^ and R. are optionally closed to a ring, are used as inhibitors. 2, stabilizers according to item 1, characterized in that pyrazoles are used in combination with other known stabilizers such as quenchers, UV absorbers, complexing agents, lubricants, antistatic agents. Stabilizers according to item 1, characterized in that the pyrazoles are used in a concentration of 0.01 to 1% by mass, in particular of 0.1 to 0.5% by mass, based on the amount of substrate, and the known additives in a concentration of 0, 01 to 0.6 percent by weight, in particular from 0.05 to 0.3 percent by weight, based on the sub stratmenge be used.