SU649728A1 - Method of obtaining low-molecular copolymers - Google Patents

Description

a pier weights (5-800) thousand. Receive a product with a mol. weighing 1000. The polymer obtained is added to lubricating oils as viscosity additives.

However, judging by the molecular weight of the polymer equal to 1000, adding it to the oil to form a composition with 10 cSt will be about 20% and the solnors with 1–10% dienes are not stable due to mechanical and thermal destruction.

In order to obtain the final product, mol. weighing 2000-4000 with increased resistance to thermal and mechanical effects and suitable for use as a viscosity additive for lubricating oils, heat treatment is carried out at 350-380 ° C for 5-40 minutes.

The resulting low molecular weight copolymers after degradation are resistant to thermal and mechanical stress and are used as a viscosity agent for lubricating oils. The method consists in obtaining low molecular weight copolymers by thermal destruction of high molecular weight copolymers of ethylene with propylene at 350-380 ° C and 10-80 mm Hg. Art. within 5-40 minutes

The conditions of thermal decomposition of ethylene-propylene rubber with a content of propylene from 25 to 40% are shown in the examples.

In addition, the examples of the thickened composition of autol-4 and the degraded polymer show the resistance to thermal and mechanical impact of the obtained new viscosity agent.

The qualities of the oil base of autol-4

Density p 200,870;

Boiling range

fractions, ° С380-430

Viscosity at 100 ° С3.88 сСг T. freezing, ° С-2

Example. The thermal decomposition of ethylene propylene copolymer is carried out at 250-400 ° C and 10-80 mm Hg. Art. from 5 to 60 min. The resulting polymer thickens the oil with VIQO 4 cSt to a viscosity of 10 cSt at 100 ° C.

5 Using a copolymer of ethylene with propylene mol. weighing (86-500) thousand, with a propylene content of 25-40%.

Temperature dependence is studied 30 at 250-400 ° C and 20 mm Hg. Art. during

12 min

The results are shown in Table. 1 (PSV is an indicator of viscosity stabilization).

Table 1

As follows from the above data, the best results were obtained using polymers with mol. weighing 2000-4000, which are at a temperature of 350-380 ° C. The polymers obtained at this temperature have better resistance to mechanical and thermal degradation, compared to polymers obtained at other temperatures.

The results of the decomposition of the ethylene-propylene copolymer as a function of time are given in table. 2

As seen from the data presented, the optimal decomposition time is 5-40 minutes. At this decomposition time, polymers can be obtained with an optimal molecular weight of 2000-4000. Best results are obtained with a decomposition time of 12 minutes. The polymer obtained is highly resistant to thermal and mechanical degradation. The amount of polymer to be added to obtain ULT is 10 cc (6.5%). Destruction, with a decomposition time of 20-40 minutes, also results in a stable polymer mol. weighing 2400-2300.

amount

polymer,

%

6.5

6.2

12.0

12.0

As follows from the above data, the change in pressure is from 10 to 80 mm Hg. Art. results in a polymer with mol. weighing between 2,000 and 4,000. The optimum pressure for decomposition is 20 mm Hg. as the polymer is consumed in a small amount and is highly resistant to mechanical and thermal degradation. With a pressure of 10 mm Hg. Art. good results are also obtained. However, maintaining such pressure presents technical difficulties. With a residual pressure of 40, 60, 80 mm Hg. Art. the resulting polymers have a mol. weight of 2000, which increases the consumption of Pbbl 2

However, in order to thicken the oil to a viscosity of 10 cSt, a large amount of polymer (9-10%) is required with a decomposition time of about .min, the polymer obtained is less stable than the time of 12min, with a percentage of 3% depolymerization.

Decomposition of ethylene-propylene copolymer depending on pressure. Splitting of the copolymer was carried out at 380 ° C for 12 minutes, the pressure was changed in the range of 10-100 ML of mercury. Art.

The test results are shown in Table. 3

T a b l ia 3 Quality of baked butter

to 12%, to obtain the necessary viscosity — 10 cCg at 100 ° C.

Thus, conducting thermal degradation at 350-380 ° C, a pressure of 10–80 mm Hg. Art., decomposition time 5-

40 minutes and allows to obtain polymers with mol. weighing from 4 thousand to 2 thousand. The optimal conditions are: temperature - 350-380 ° C; pressure of 20 mm Hg. st; time 12 min., allowing to obtain polymers with mol. weighing 2000, 4000, having the best values of thermal and mechanical stability; in addition, the required amount of polymer for thickening the oil to cSt does not exceed 6.2%.

Claims (2)

1. US Patent No. 3687849, cl. 252-47,5, publ. 1972. 2. US patent No. 3687905, cl. 260-78.4, publ. 1972.