RU2640784C1 - Rubber mixture on basis of propylenoxide rubber for frozen-oil resistant products - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: rubber mixture includes, pts wt: propylenoxide rubber SKPO - 75-95, epichlorhydrine rubber SKEHG-ST - 5-25, stearic acid 0.5-3.0, zinc oxide - 2.0-10.0, captax - 0.3-1.0, thiuram - and 0.5-2.0, sulfur - 0.5-2.0, filler-technical carbon - 0-100.

EFFECT: rubber mixture according to the invention makes it possible to obtain rubber with high frost resistance and strength while maintaining oil resistance.

1 tbl, 1 ex

Description

The invention relates to rubber compounds for frost, oil resistant products based on propylene oxide rubber. Such rubber compounds are intended for use in the automotive, oil and oil refining industries, as well as other industries where high oil and frost resistance are required.

A rubber mixture based on propylene oxide rubber of the following composition is known: SKPO propylene oxide rubber (100.0 parts by mass), stearic acid (1.0 parts by mass), zinc oxide (5.0 parts by mass), natural zeolites ( 3.5-14.0 parts by mass), dibutyl phthalate (1.5-6.0 parts by mass), captax 2-Mercaptobenzthiazole (2.0 parts by mass), thiuram disulfide (2.0 parts by mass) .), carbon black P-803 (60.0 mass parts), sulfur (1.5 mass parts).

Vulcanizates have a high coefficient of frost resistance to elastic recovery under compression (KV) at -35 ° C 0.64-0.7.

However, these vulcanizates have medium physical and mechanical properties:

- tensile strength 10.4-12.4 MPa;

- elongation at break of 239-262%.

([RU 2294341] C08L 19/00, C08K 13/02, published 09.27.2006, priority 03.06.2005.)

In addition, the rubber composition contains a dibutyl phthalate plasticizer, which is washed out over time, which leads to a sharp deterioration in frost resistance and physical and mechanical properties.

A known rubber mixture based on propylene oxide rubber of the following composition: SKPO propylene oxide rubber (100.0 parts by mass), stearic acid (1.0 parts by mass), zinc oxide (5.0 parts by mass), dibenzothiazole disulfide (1 5 parts by mass), thiuram disulfide (1.0 parts by mass), phenyl-β-naphthylamine (2.0 parts by mass), natural bentonites (0.5; 1.0; 3.0; 5 , 0; 10.0 mass parts), P-803 carbon black (60.0 mass parts), sulfur (1.5 mass parts), dibutoxyethyl adipate (10.0 mass parts)

([RU 2493183] C08L 71/02, C08K 13/02, C08K 3/06, C08K 5/09, C08K 5/372, C08K 5/10, published 09/20/2013, priority 05/11/2012.)

Vulcanizates have a high coefficient of frost resistance to elastic recovery under compression (KV) at -35 ° C 0.78-0.88.

However, the physical and mechanical properties are quite low:

- tensile strength 6.8-7.8 MPa;

- elongation at break 104-192%.

In addition, the rubber composition contains a plasticizer dibutoxyethyl adipate, which is washed out over time. Frost resistance is sharply deteriorating.

The closest analogue in technical essence and the achieved result is a rubber mixture based on propylene oxide and epichlorohydrin rubbers. The composition contains: epichlorohydrin rubber (SKEHG-ST) (50.00 parts by mass), propylene oxide rubber (SKPO) (50.00 parts by mass), sulfur (1.10 parts by mass), magnesium oxide (MgO ) (1.00 parts by mass), zinc oxide (ZnO) (5.00 parts by mass), P-803 carbon black (75.00 parts by mass), P-324 carbon black (15.00 parts by mass), dibutyl sebacinate (DBL) (8.00 parts by mass), stearin (1.00 parts by mass), captax (0.80 parts by mass), thiuram (0.50 parts by mass) .), nickel dibutyl dithiocarbomatate (Ni DBDTK) (1.00 mass parts).

([RU 2284338] C08L 19/00, C08K 3/06, published September 27, 2006, priority June 3, 2005.)

The rubber compound provides effective oil- and good frost resistance. But at the same time, the rubber mixture has a low conditional tensile strength - not more than 7.8 MPa, elongation at break ~ 230%. In addition, to achieve good frost resistance, the introduction of a plasticizer is necessary, and during operation, as a result of washing out the latter, frost resistance deteriorates.

A method of obtaining a rubber mixture according to the above recipe consists in mixing the ingredients on standard equipment in the following sequence of their introduction:

The objective of the invention is to provide a rubber mixture based on propylene oxide rubber, the vulcanizates of which have, along with good oil resistance, high strength characteristics and high frost resistance.

The problem is achieved in that the rubber mixture for frost, oil-resistant products based on propylene oxide rubber, including epichlorohydrin rubber, sulfur, captax, thiuram, stearic acid, zinc oxide, if necessary, filler, contains components in the following ratio, mass. hours:

 Propylene oxide rubber 95.0-75.0  Epichlorohydrin rubber 5.0-25.0  Stearic acid 0.5-3.0  Zinc oxide 2.0-10.0  Captax 0.3-1.0  Tiuram 0.5-2.0  Sulfur 0.5-2.0  Filler 0.0-100.0

The essence of the invention lies in the fact that the rubber mixture is obtained by mixing on rollers at a temperature of 55-65 ° C, followed by vulcanization according to the regime of 160 ° C × 15 minutes

SKPO rubber (TU 2294-067-16810126-2003) is used as propylene oxide rubber. As epichlorohydrin rubber, for example, rubber SKEHG-ST (TU 2294-075-00151963-2001) is used.

Kaptax (GOST 739-74), thiuram (GOST 740-76), stearic acid (GOST 6484-96) are used as vulcanization accelerators; zinc oxide (GOST 10262-73) is used as an activator of vulcanization accelerators; sulfur is used as a vulcanizing agent (GOST 127.1-93).

As a filler of the rubber mixture, carbon black is used, for example, grades P-324, P-234, P-514, P-803 (GOST 7885-86).

The following examples illustrate but do not limit the technical solution:

Example 1

On the rollers at a temperature of rolls of 55-65 ° C, 95.0 masses are heated for 3 minutes. including propylene oxide rubber SKPO and add to it 5.0 mass. including epichlorohydrin rubber SKEHG-ST. The rubbers are mixed for 2 minutes. Then, 0.5 masses are introduced into the rubber mixture. including stearic acid and roll for another 2 minutes. After that, 2.0 masses are introduced. including zinc oxide, roll 3 minutes. After zinc oxide, 0.3 masses are added. including captax, 0.5 mass. h. Tiurama and all together roll another 2 minutes. Then enter 0.5 mass. including sulfur and roll the rubber mixture for a minute. The resulting rubber mixture is passed on a thin gap (0.4 mm) roll 6 times, after which it is released in the form of a sheet. The total mixing time is 18 minutes. The resulting mixture was vulcanized in a press at a temperature of 160 ° C for 15 minutes.

For convenience, all examples are summarized in table 1.

The resulting rubber compounds were subjected to the following tests: determination of physical and mechanical properties (GOST 270-75), determination of the coefficient of frost resistance by elastic recovery under compression (Kv) (GOST 13808-79), determination of the degree of swelling in a hydrocarbon medium (GOST 9.030-74).

As shown by the tests (table 1), the proposed rubber compound has higher frost resistance and strength characteristics while maintaining oil resistance compared to the prototype. It should be noted that the rubber mixture has improved frost resistance without the use of a plasticizer.

Claims (2)

A rubber mixture based on propylene oxide rubber, including epichlorohydrin rubber, stearic acid, zinc oxide, captax, thiuram, sulfur, if necessary, a filler, characterized in that it contains components in the following ratio, wt. hours:  propylene oxide rubber 95.0-75.0  epichlorohydrin rubber 5.0-25.0  stearic acid 0.5-3.0  zinc oxide 2.0-10.0  captax 0.3-1.0  tiuram 0.5-2.0  sulfur 0.5-2.0  filler 0.0-100.0