DE1028330B - Process for stabilizing hydrocarbon polymers - Google Patents

Description

GERMAN

The polymers of polymerizable hydrocarbons are resistant to the action of heat, oxygen and light not constant. Rather, they change their properties to their disadvantage, in particular worsen them the mechanical and electrical properties, the appearance and possibly also the processability. You can prevent these disadvantageous changes or at least stop them if you use the polymers so-called stabilizing agents are added. A wide variety of substances have already been proposed as such been. However, these usually only work in one direction or the other; so far there are no stabilizers known that the polymers in a satisfactory manner at the same time against the action of Protect heat, oxygen and light.

It has been found that polymers of polymerizable Hydrocarbons can stabilize more advantageously if you use small amounts of dianils of the general formula

R ₁ R ₂

= C-C =

Tan

ho

X, process for stabilizing hydrocarbon polymers

Applicant:

Chemical works Hüls Aktiengesellschaft, Marl (Kr.Recklinghausen)

Dr. Franz Broich, Dr. Kurt Kopetz, Dr. Hermann Paul and Dr. Ferdinand List, Marl (district of Recklinghausen),

have been named as inventors

lower carbon number are substituted. The total number of carbon atoms in the radicals R ₁ to R ₆ should be 2 to 32, expediently 2 to 22. The radicals R ₁ to R ₆ can all be different, but in general the symmetrical dianiles are preferred because of their easier accessibility. Suitable dianiles are, for example:

CH ₃ CH ₃

used, in which R ₁ and R _{2 are} hydrogen, alkyl or aryl groups, the total number of carbon atoms present in the two groups is not more than 12, and R ₃ , R ₄ , R ₅ and R _{6 are} hydrogen or alkyl groups having a maximum of 10 carbon atoms where the total number of _{carbon atoms present in the radicals R 1} , R ₂ , R ₃ , R ₄ , R ₅ and R _{6 is} between 2 and 32. The dianils corresponding to the above formula CH, are obtained in a manner known per se by condensation of 1,2-dioxo compounds with o-aminophenols. The 1,2-dioxo compounds chosen are, for example, glyoxal, ketoaldehydes, such as methylglyoxal, or 1,2-diketones, such as hexanedione- (3,4), diacetyl, 2-methylhexanedione- (4,5) and benzil. With the same success one can also use cyclic diketones,]

like cyclopentanedione- (1,2), l-methyl-cyclohexanedione- (3,4) and 1,2-cyclohexanedione. Generally preferred one symmetrical 1,2-diketones. As o-aminophenols are in addition to the o-aminophenol itself with a or o-aminophenols substituted by two alkyl groups are suitable. The chain length of the alkyl radicals can be up to 12 carbon atoms. In general, good results will be obtained if the total number of Carbon atoms in the alkyl chains of the o-aminophenols is up to 24. It is particularly advantageous from o-aminophenols starting with a tertiary alkyl radical, for example with the tertiary butyl radical, as well as optionally with a further alkyl radical

N = C C = N-

OH

HO

Diacetyl-di- (2,2'-oxy-anil)

CH,

-C

CHo CHq

-N = C C = N

-OHH O

CH ₈ X / ~ "- \ / CH ₃

Diacetyl-di- (2,2'-oxy-5,5'-tertiary-butyl-anil)

CH ₃ CH ₃

j—

OH

- C = N - * HO-L

Diacetyl-di- (2,2'-oxy-5,5'-hexyl-anü)

Ho Η «
CC

H ₂ C

CH "

-N = C C = N -

OHH O

V
Cyclohexanedione- (1,2) -di (2,2'-oxy-anil)

709 960/434

also benzu-di- (2,2'-oxy-5,5'-tertiary-butyl-anil), diacetyl-di- (2,2'-oxy-3,3'-methyl-5,5'-tertiary -butyl-anil). These dianiles are used in "amounts of 0.001 to 0.1 percent by weight, based on the polymer, applied and in a manner known per se prior to exposure to Incorporated heat, oxygen or light.

Polymers of polymerizable hydrocarbons are thermoplastic and elastomeric Materials such as high-pressure polyethylene, low-pressure polyethylene, polyisobutylene, polystyrene, polybutadiene, Polyisoprene and their copolymers, as well as similarly structured natural substances, such as natural rubber, understood. Furthermore, the not so high molecular weight hard wax, soft wax or ointment-like ones are added to these polymers Products of the polymerization of hydrocarbons as well as corresponding natural products.

Even in the small amounts mentioned above, the dianils protect the polymers from polymerizable ones Hydrocarbons satisfactory from the action of heat, oxygen and light. The dianiles are physiological flawless and, in contrast to the well-known, highly effective stabilizers, do not cause any discoloration. The physiologically questionable stabilizing agents known from US Pat. No. 2,582,510, for example, namely combinations of sulfur with thiuram disulfides, severe discoloration and one unpleasant odor of the stabilized polymers. Also that in British Patents 571,943 and 594 891 proposed stabilizers, namely phenols or non-primary aromatic amines or Mixtures of phenyl-a-naphthylamine and diphenylp-phenyldiamine, result in strong and undesirable discoloration of brown or gray and are physiological not flawless, so they are therefore suitable for other areas of application out of the question.

example 1

A low-pressure polyethylene with a molecular weight of 100,000, which was produced by discontinuous polymerization, is intimately mixed with varying amounts of a dianil and granulated. The granules are processed into test specimens at 190 ° C. by injection molding. After aging at 100 ° C. in a drying cabinet after 5, 10 and 20 days, the molecular weight, the dielectric loss factor at tgö, the impact strength, the softening point, the boiling stability and the reduced viscosity are determined on these test specimens.

The cooking stability is determined by looking at

A normal injection molding machine made 2 mm thick plates of 45 x 45 mm, one edge of which is rounded is, immersed in boiling water for half an hour, then the shortening of the platelets in the longitudinal direction, d. H. determined from the apex of the rounded edges to the base edge and this shortening calculated in percent.

For comparison, one is not stabilized and one with the most commonly used stabilizing agent 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol) stabilized sample, which is prepared and treated in the same way, used. The values obtained are summarized in the table below.

Test item duration
at 100 ° C

Molecular weight

tg δ · ΙΟ " ³ at 800 Hz impact strength
cm kg / cm ²

Softening point

Cooking stability

Vo
Shortening

Reduced
viscosity

? 7 ~ red

Stabilized with 0.01% diacetyl-di- (2,2'-oxy-anil)

5 days ,
10 days,
20 days

82,000 82,000 78,000

0.1 5.0

no break
no break

6O ⁰ C
71 ° C
66 ⁰ C

Stabilized with 0.01% cyclohexanedione- (1,2) -di (2,2'-oxy-anil)

5 days
10 days
20 days

5 days
10 days
20 days

82,000 80,000 73,000

0.1 4.6

no break
no break

65 ° C
67 ° C
70 ° C

Stabilized with 0.01% diacetyl-di- [2,2'-oxy-5,5 '- (tert-butyl) -anil]

after 5 days
after 10 days
after 20 days

after 5 days
after 10 days
after 20 days

1.3

1.0

0 0

20th , 0

2.8 2.7

20th , 0

2.75
2.55

78,000
73,000
72,000 0.1
5.6 no break
no break no break
4.5 65 ° C
73 ° C
68 ° C 1.1
0
0.4 -t with 0.01% 2,2'-methylene-bis- (4-methyl-6-tert-butyl-phenol) 0.1
8.0 no break
3.5 70 ° C
68 ° C
86 ° C 0.9
0.7
0 2.70
2.55
2.50 Not stabilized 82,000
65,000
39,000 78,000
55,000
43,000 ° ±
9.6 63 ° C
70 ° C
78 ° C 0
0
0.5 2.7
2.0
1.7 2.8
2.3
1.55

Example 2 ⁶ 5 does not discolor and the molecular weight remains

unchanged.

A 1 mm thick plate made of low-pressure polyethylene. Even if only 0.01 percent by weight of diacetyl

with a molecular weight of 100,000, di- (2,2'-oxy-anil) is used with 0.1 weight for stabilization percent diacetyl-di- (2,2'-oxy-anil) stabilized and then plate after 30 days of exposure to ultraviolet light Irradiated with ultraviolet light for 30 days. The plate 70 no change.

The same good results are also obtained when using a sheet made of polystyrene with 0.1 percent by weight Diacetyl-di- (2,2'-oxy-anil) stabilized and then irradiated with ultraviolet light for 30 days.

Example 3

A butadiene-styrene copolymer known under the trade name Buna S are 0.1, 0.5 and 1% diacetyl-di- (2,2'-oxy-anil) fed. Then the oxygen increase of the mixture at constant gas pressure measured at 130 ° C. according to Mesrobian and Tobolsky (cf. Journ. Polymers Science, Vol. 2, 1947, p. 463). The most favorable delay in oxygen uptake is achieved with 0.1% of the dianil.

Claims (1)

PATENT CLAIM: Process for stabilizing hydrocarbon polymers, characterized in that the stabilizing agent used is dianils of the formula
R ₁ R ₂ / V Γ XN - v- <■ ν, * -
-OH used, in which R ₁ and R _{2 are} hydrogen, alkyl or aryl groups, the total number of carbon atoms present in the two groups is not more than 12, and R ₃ , R ₄ , R ₅ and R _{6 are} hydrogen or alkyl groups having a maximum of 10 carbon atoms and the total number of _{carbon atoms present in the radicals R 1} , R ₂ , R ₃ , R ₄ , R ₅ and R _{6 is} between 2 and 32. Considered publications:
British Patent Nos. 571,943,594,891;
U.S. Patent No. 2,582,510. © 709 960/434 4.58