DE2328037C3 - Process for the fluorination of the surface of vulcanized rubber moldings - Google Patents

Description

The invention relates to methods for fluorinating the surface of vulcanized rubber molded articles with antimony pentafluoride.

Vulcanized rubber with a fluorinated surface has a low coefficient of friction, whereby products made of such material, e.g. B. reinforced sealing sleeves, for hermetic sealing of friction assemblies be used.

It is a process for fluorinating the surface of rubber molded articles by immersing them in a bath with a fluorinating agent, the liquid antimony pentafluoride, and then washing the Products with water, a 5 to 20% aqueous solution of alkali metal carbonate and known again with water (see SU-PS 3 30 177).

A disadvantage of this process is a very large consumption of antimony pentafluoride as a result of it Entrainment through the surface of the molded body. Particularly large amounts of antimony pentafluoride are carried away by figures. If you have such moldings after taking them out of the bathroom leaves over this bath for the most complete possible drainage of the liquid, this takes a lot of time. resulting in uneven fluorination of the surface of the molded body and even its destruction leads.

On average, ^{2 to 4 kg of antimony pentafluoride are consumed per 1 m 2 of} the surface of the shaped bodies (for example reinforced rubber seals with an outside diameter of about 100 mm). As a result of such a high consumption of the fluorinating agent, it is unprofitable to use the known method for fluorinating the surface of vulcanized rubber on an industrial scale.

Another disadvantage of the known method is that when immersing a Molded body with a complicated configuration in the bath with the antimony pentafluoride on its surface individual places can form air bags, which the access! of the fluorinating agent in these areas. This makes the fluorination of the surface uneven.

Another disadvantage of the known method is the entrainment of the antimony pentafluoride through the Shaped body connected especially at the points where a longer adhesion of the liquid is possible. At the Transferring the body from the bath with the antimony pentafluoride reacted into the water for washing the antimony penia fluoride violently with water with evolution of hydrogen fluoride and a significant Amount of heat. These two factors have an intense effect on rubber and lead to its localization Damage.

In addition, some disadvantages of fluorination with the liquid antimony pentafluoride are necessary associated with working with larger masses of the aggressive liquid (effort for the transport of the Liquid, for heating it, etc.).

The fluorination process described in "Sovjet Rubber technology" 3, 1969, 25-26 consists in that one rubber molded body immediately above the surface of liquid antimony pentafluoride, where the Concentration of the vapors is sufficient for the fluorination to hold.

It is technically impracticable for the following reasons:

1. As a result of uncontrollable convection currents it is not possible to obtain the required amount at the point where the body to be fluorinated is located To keep the antimony pentafluoride concentration constant, which is why a constant process management is also excluded.

2. There are huge free areas for the treatment of a large number of rubber moldings of antimony pentafluoride is required, since the fluorination only takes place in the immediate vicinity of these surfaces can be carried out.

3. The entire mass of antimony pentafluoride is quickly contaminated by the fluorination products of the vulcanized rubber (FH, SbF ₃ , Sb fluorochlorides when treating vulcanized rubbers containing Cl, etc.), which means heavy consumption and frequent replacement in the reaction zone .

The situation is completely different when using SbF ₅ vapors mixed with a carrier gas.This mixture (hereinafter referred to as the gas reagent) can easily be conveyed into the fluorination reactor, i.e. the production of the gas reagent and the fluorination of the vulcanized rubber take place in different ways Apparatus. The concentration of the SbFs vapors in the gas reagent can easily be regulated and kept constant.

Regarding technical progress, it should also be said that this essentially consists in the fact that one According to the invention, the fluorination can be carried out on an industrial scale. the Application of the vapors with a carrier gas wit nitrogen makes it possible to do this in a simple manner can be transported by cables, it is easy to dose and thermostate. By being able to: Controlling processes to the extent desired will significantly reduce the percentage of waste.

The purpose of the present invention is to avoid the disadvantages mentioned
'The invention was based on the object in, _m method for fluorinating the surfaces of ulcanized rubber moldings, which in their treatment with a fluorinating agent, the anti-ion pentafluoride, at a temperature of 20 to 140 ^c C _n d subsequent washing with a 5- to 20% igen ^ aqueous solution of alkali metal carbonate and with water is to change the conditions of the treatment of the moldings with the antimony pentafluoride in such a way that the unproductive entrainment by the moldings is practically completely excluded, the access of the fluorinating agent to any point on the surface of the to be fluorinated vulcanized rubber molded body is enabled, local damage to the fluorinated molded body as a result of overheating and the action of hydrogen fluoride during washing are excluded and the necessity of working with larger masses of the liquid antimony pentafluoride is avoided.

The invention therefore relates to a process for fluorinating the surface of vulcanized rubber moldings by treatment with vaporous antimony pentafluoride mixed with a carrier gas at a temperature of 20 to 140'C and Washing the fluorinated surface with a 5-20% aqueous solution of alkali carbonate and with water, which is characterized in that one the moldings with a mixture of antimony pentafluoride vapors and nitrogen or air as the inert carrier gas at a concentration of 150 to 310 mg / l of the antimony pentafluoride in the gas mixture in the fluorination reactor with a degree of exchange of 10 to Treated 20 volumes / hour at a temperature of 40 to tOO ° C, with the treatment of the Shaped body directed flow of the reaction gas by continuous evaporation of one in the flow of the Carrier gas at a temperature of 150 to 170 ° C Generated introduced stream of antimony pentafluoride

Such a gas phase treatment makes it possible to practically completely exclude the unproductive consumption of antimony pentafluoride as a result of being carried away through the surface of the moldings mentioned and the consumption of the fluorinating agent of 2 to 4 kg / m ^{2 of} vulcanized rubber, as in the known liquid phase process is the case to decrease to 100 to 200 g / m ^2.

Another advantage of the proposed method is that the antimony pentafluoride in the gas phase has equal access to the entire surface of the molding regardless of its configuration, whereby a uniform fluorination of this surface is brought about. When performing the Fluorination under the conditions of the proposed process increases the possibility of damage of the fluorinated molding completely excluded during washing, because on the surface after only traces of antimony pentafluoride remain after the discharge from the fluorination reactor Presence does not lead to a violent reaction with water. The proposed method possesses compared to the known some advantages, which with the exclusion from the work of larger masses of the liquid antimony pentafluoride are connected (economy of the transport of the liquid antimony dentafluoride and low energy consumption for heating it).

The flow of the reagent gas, passed for the treatment of the molded bodies made of vulcanized rubber, can be generated by bubbling the carrier gas through liquid antimony pentafluoride, which has a temperature of 20 to 80 ° C., or by continuously evaporating a jet of the liquid antimony pentafluoride which is introduced into the flow the carrier gas is introduced at a temperature of 150 to 170 ⁰ C ίο.

Any gas which under the treatment conditions with the fluorinating agent can be used as the carrier gas is inert, e.g. B. helium, argon, nitrogen, can be used. The latter is due to it Accessibility preferred. In the process of fluorinating the surface of vulcanized material resistant to oxidation Rubber, e.g. based on fluororubbers, can also use air as a carrier gas will.

The method of the invention is as follows accomplished.

The liquid antimony pentafluoride is introduced into an evaporator. A container made of a material resistant to the action of antimony pentafluoride, for example aluminum, serves as the evaporator. The inside of the container can be lined with rough polytetrafluorethylene. Said container is provided with a pressure mixer for introducing the carrier gas and a pipe for leading out the reagent gas. Said container also has a heating mantle, preferably with electric heating, for holding the liquid antimony pentafluoride in the evaporator at the required temperature (in a range of 20 to 8O ⁰ C) depending on the type of rubber to be fluorinated.

The described evaporator with the liquid antimony pentafluoride is run at constant speed the carrier gas and leads the reagent gas out of the vaporizer, which is a Is a mixture of antimony pentafluoride vapors with the carrier gas. The concentration of antimony pentafluoride in the reagent gas may be vulcanized depending on the type of the to be fluorinated Rubber by the rate of bubbling of the carrier gas through the liquid antimony pentafluoride as well as by the temperature of the antimony pentafluoride in the evaporator, preferably after the latter method, can be controlled by adjusting the rate of bubbling of the carrier gas is kept constant and optimal for the particular volume of the fluorination reactor. The preferred one The concentration of the antimony pentafluoride in the carrier gas is in a range from 150 to 310 mg / l 5: ü reagent gas.

The reagent gas emerging from the vaporizer in the form of a continuous stream is fed to the Fluorination reactor for treating the molded body.

In addition to the method described, the flow of the reagent gas which is fed to the fluorination reactor can be generated as follows. An evaporator, which is a heated container of small dimensions made of a material resistant to the action of antimony pentafluoride, is passed at a temperature above the boiling point of the antimony pentafluoride, namely at 150 to 170 ^° C. at constant speed

the flow of the reagent gas through. In the mentioned Current is continuously introduced in the form of a jet of liquid antimony pentafluoride, which upon entry momentarily evaporated into the heated vaporizer, entrained by the flow of reagent gas and out of the Evaporator led out wi. d.

The vulcanized rubber molded bodies to be fluorinated should have a clean surface that free from mechanical impurities, from the oil migrating from the rubber (softening agent) is. Therefore, if necessary, the molded articles made of vulcanized rubber are washed before the Fluorination with an aqueous solution of soap or other surfactant, for example of the polyoxyethylated alkylphenol, or with an organic solvent, for example acetone, and then dries.

The fluorination of the surface of molded bodies made of vulcanized rubber is carried out in a reactor, which is a container made of a material resistant to the action of antimony pentafluoride, with a hermetically sealable lid, pipelines for introducing the reagent gas and for discharging the exhaust gas as well as with a heating jacket, preferably with electrical heating, is provided. Before they are introduced into the reactor, the molded bodies made of vulcanized rubber are placed in a container that represents aluminum disks which are drawn together in the center with a steel or aluminum rod. The shaped bodies are arranged in the reactor in such a way that free access of the reagent gas to all surfaces to be fluorinated is ensured. The molded bodies are then clamped between the aforementioned disks and the container is introduced into the fluorination reactor together with the molded bodies made of vulcanized rubber. The reactor is closed and the temperature necessary for carrying out the fluorination process is generated in it. As pointed out above, the fluorination temperature is in a range from 20 to 140 ⁰ C, preferably from 40 to 100 ° C, and is selected depending on the type of the vulcanized rubber to be fluorinated. A stream of the reagent gas emerging from the evaporator is then passed through the reactor at a rate which corresponds to the predetermined degree of exchange of the reagent gas in the reactor, which is preferably 10 to 20 volumes / hour. amounts to. The degree of exchange of the reagent gas in the reactor can be increased or decreased compared to the aforementioned optimal limit. However, lowering the exchange rate to less than 10 volumes / hour. lead to a deterioration in the uniformity of the fluorination, while an increase in the degree of exchange to more than 20 volumes / hour. leads to an unproductive breakthrough of larger amounts of the unreacted antimony pentafluoride through the fluorination reactor and a great burden on the device collecting the antimony pentafluoride.

The fluorination is carried out under the above-mentioned conditions for a period of time is determined by the type of vulcanized rubber to be fluorinated, and preferably in one Range from 10 to 60 minutes. After the fluorination has ended for 6 seconds, the reactor is filled with pure carrier gas to blow off the unreacted antimony pentafluoride and other volatile fluorine compounds from the Surface of the molded body made of vulcanized rubber and of the inner walls of the reactor flushed. Blowing off is expedient until a concentration of the antimony pentafluoride has been achieved carried out in the atmosphere of the reactor of less than 0.003 mg / l.

The gases emerging from the reactor during fluorination and purging are passed through Facilities by the unreacted antimony pentafluoride and for the discharge into the atmosphere Catch unwanted additions (hydrogen fluoride) and the Anlimonpemafiuorid in the evaporator redirect. The pure carrier gas, separated from the unreacted antimony pentafluoride and the others volatile fluorine compounds, can be discharged into the atmosphere or returned to the technological cycle (the vaporizer for producing reagent gas and the fluorination reactor for venting supplied).

After the blow-off has ended, the reactor is opened, from which the container with the shaped bodies is opened Carried out of vulcanized rubber and placed in a washing bath, which has a 5- to 20% aqueous solution of alkali metal carbonate, for example sodium carbonate. The intended purpose of the wash bath is to remove the fluorine and antimony compounds from the surface of the molded body to remove vulcanized rubber that remain there after blowing off. The container is held in the said bath 5 to 10 minutes, then brings into the water where the molded body is made of vulcanized Wash rubber for 5 to 10 minutes. Then you take the container out of the water out, carries out of this the molded body made of vulcanized rubber and dries it, for. B. at in the air or in a drying drum (with warm air).

The fluorination according to the proposed method can vulcanized rubbers that are against the The action of strong heterolytic reagents (antimony pentafluoride is one such reagent) is persistent are e.g. B. vulcanized rubber based on hydrocarbon or halogenated hydrocarbon polymers (e.g. from natural rubber, stereoregular butadiene and isoprene rubbers, butadiene-styrene, Chloroprene rubber, ethylene propylene rubber and copolymers of fluorine-containing monomers) and butadiene-acrylonitrile.

In the proposed method, the consumption of the antimony pentafluoride depends on the type of vulcanized rubber to be fluorinated. For example, in the fluorination of vulcanized rubber based on natural, butadiene-styrene and butadiene-acrylonitrile rubber, the consumption of antimony pentafluoride is around 50 to 100 g / m ^{2 of} the fluorinated surface and in the fluorination of vulcanized rubber on the base of chloroprene rubber 200 g / m ^{2 of} the fluorinated surface.

For a better understanding of the present invention, the following examples of the implementation of the proposed procedure.

example 1

For the production of reagent gas one used a vaporizer, which an aluminum container of Representing 30 cm in diameter and 40 cm in height, the one with a jacket with electric heating and piping for introducing the carrier gas (the dry

Nitrogen) and leading out the reagent gas is provided. To the pipeline for introducing nitrogen a pressure mixer was connected, which reached almost to the bottom of the evaporator.

10 kg of liquid ammonium pentafluoride were introduced into the evaporator and the electric heater was switched on. After the liquid antimony pentafluoride had reached a temperature of 40 ^° C. in the evaporator, nitrogen was blown through it. The resulting reagent gas, which is a mixture of the vapors of antimony pentafluoride with the carrier gas, emerged from the evaporator and entered the fluorination reactor as a continuous stream for treating the molded articles made of vulcanized rubber, ι S

Surfaces made of vulcanized rubber based on butadiene-acrylonitrile rubber containing 40% acrylonitrile members were subjected to fluorination. The molded bodies made of vulcanized rubber were metal-reinforced sealing collars with an outer diameter of 100 mm and plates with the dimensions 140x 140x2 mm. The aforementioned sealing collars in a number of 300 pieces and the plates in a number of 3 pieces were placed in a container which Represents aluminum disks pulled together at the center with a steel or aluminum rod. These bodies were arranged in the container in such a way that free access of the reagent gas to all surfaces to be fluorinated is ensured. The molded bodies made of vulcanized rubber were then clamped between the abovementioned aluminum disks and the container was placed together with them in the fluorination reactor. The reactor was closed and heated until an internal temperature of 50 ^° C. was established. A stream of the reagent gas emerging from the evaporator was then passed through the reactor at the temperature mentioned for 40 minutes. The degree of exchange of the reagent gas in the fluorination reactor was 20 volumes / hour, and the concentration of the antimony pentafluoride in the reagent gas was 250 mg / l of the reagent gas.

After the completion of the fluorination, the reactor was ^{purged with pure nitrogen at 50 °} C. for 40 minutes. The supply of nitrogen was then interrupted, the reactor was opened and the container with the molded bodies made of vulcanized rubber was placed in a vessel with a 10% strength aqueous solution of sodium carbonate, where this was kept for 5 to 10 minutes while the solution was stirred. Then the container was placed in a vessel with water, where the vulcanized rubber moldings were washed for 5 to 10 minutes, after which the container was taken out of the water, the vulcanized rubber moldings were carried out therefrom and exposed to air or in a drying drum (with warm air) dried.

The molded bodies made of vulcanized rubber with a fluorinated surface were subjected to a test to determine the coefficient of sliding friction, the temperature in the "rubber / metal" contact zone (in the friction zone) and the tensile strength of the vulcanized rubber. The coefficient of sliding friction and the temperature in the friction zone were measured at a speed of 2 m / s and a pressure of the vulcanized rubber against the metal of 2 kp / cm ² .

The following results were obtained (in brackets are the same characteristic values for non-fluorinated vulcanized rubber):

Coefficient of sliding friction 0.3 (1.4); Temperature in the friction zone 88 ⁰ C (210 ° C); Tensile strength of the vulcanized rubber 140 kgf / cm ² (150 kgf / cm ² ). The vulcanized rubber fluorinated with liquid ammonium pentafluoride had a tensile strength of 110 kgf / cm ² with the same coefficient of sliding friction.

The life of the sealing sleeves with fluorinated surface in an automotive assembly is up to to the occurrence of a leak associated with the bursting and keratinization of the working edge of the cuff, was 160,000 km and for similar sleeves with a non-fluorinated surface 80,000 km.

Example 2

Moldings made of vulcanized rubber, which are made of vulcanized rubber on the basis of butadiene-acrylonitrile, which contains 40% acrylonitrile members, with a large content of plasticizer (30% dibutyl sebazinate) were washed before fluorination with acetone to remove the surface of the vulcanized rubber leaked plasticizer and held for 15 minutes in the air Removal of acetone.

The preparation of the reagent gas and the fluorination of the surface of the vulcanized molded body Rubber with subsequent rinsing of the fluorination reactor and washing of the moldings Vulcanized rubber was carried out as described in Example 1.

When testing the molded body made of vulcanized rubber with a fluorinated surface under the im In the conditions described in Example 1, the following results were obtained (in brackets are the same Characteristic values listed for non-fluorinated vulcanized rubber):

Coefficient of sliding friction 0.3 (1.5); Temperature in the friction zone 86 ⁰ C (220 ⁰ C); Tensile strength of the vulcanized rubber 150 kgf / cm ² (150 kgf / cm ² ).

Example 3

Moldings made of vulcanized rubber, which are made of vulcanized rubber on the basis of butadiene-acrylonitrile, containing 40% acrylonitrile members and a heavily contaminated surface had, they were washed with stirring before fluorination with an aqueous solution of a surfactant (sodium stearate or polyoxyethyl octylphenol) and then with water and air dried.

The preparation of the gas as well as the fluorination the surface of the molded body made of vulcanized rubber with subsequent rinsing of the The fluorination reactor and the washing of the vulcanized rubber moldings were carried out as in Example I. described carried out.

When testing the molded body made of vulcanized rubber with a fluorinated surface under the im In the conditions described in Example 1, the following results were obtained (in brackets are the same Characteristic values listed for non-fluorinated vulcanized rubber):

Equation number 0.3 (1.4); Temperature in the friction ^{zone 81 0} C (210T); Tensile strength of

709 441/293

ίο

vulcanized rubber 150kp / cm ² (150 kgf / cm ^2).

Example 4

The surface of the molded articles made of vulcanized rubber, which consists of Vulcanized rubber on the basis of ethylene-propylene rubber were made and sheets with represented the dimensions 140 χ 140 χ 2 mm.

The preparation of the reagent gas and the fluorination of the surface of the vulcanized molded body Rubber with subsequent rinsing of the fluorination reactor and washing of the moldings Vulcanized rubber was carried out analogously to Example 1.

In this case, the temperature of liquid antimony pentafluoride was in the evaporator 3O ⁰ C, the temperature in the fluorination 7O ⁰ C, the degree of exchange of the reagent gas in the fluorination reactor 10 VoIumen / hr., The concentration of antimony pentafluoride in the reagent 200 mg / 1 reagent, the duration of fluorination 10 minutes, the duration of rinsing the Fluorierungsreaktors at a temperature of 70 ⁰ C for 30 minutes.

The molded bodies made of vulcanized rubber with a fluorinated surface were subjected to a test,

Table I.

by looking at the coefficient of static friction on a tribometer as well as the tensile strength of the vulcanized rubber determined. The following results were obtained (in brackets are the same Characteristic values listed for non-fluorinated vulcanized rubber):

Static friction coefficient 0.15 (1.0);

Tensile strength of the vulcanized rubber was 120 kg / cm ² (120 kg / cm ² ).

Example 5

The surface of the moldings made from vulcanized rubber was subjected to the fluorination Made of vulcanized rubber based on chloroprene rubber.

The preparation of the reagent gas and the fluorination of the surface of the vulcanized molded body Rubber with subsequent rinsing of the fluorination reactor and washing of the moldings Vulcanized rubber was carried out analogously to Example 1. The conditions under which the Preparation of the reagent gas, the fluorination of the surface of the molded body made of vulcanized rubber and the flushing of the fluorination reactor are carried out are listed in Table 1.

No. of
Try it

Temperature of
liquid antimony pema fluoride
in the evaporator

( ⁰ C)

Temperature in the multiple of the concentration of the duration of the fluorination exchange of the reagent antimony pcnta- fluo-

gases im fluorinating fluoride im

reactor reagent gas

(Volume / h)

reactor

rc)

20th

25th
30th

40
45
55

(mg / 1)

20 20 10

150
180
200

riening

(min)

30th
45
60

Conditions of
Flushing the
Fluorination reactor

temperature
("C)

40
45
55

Duration of

Flushing

(min)

30th
30th
30th

The molded bodies made of vulcanized rubber are listed with 7 ,, ™ ν ι ■ u ·. ■ j

fluorinated surface was subjected to a test Ereebni "- Sn ^{V <} T ^g ' ^Clch _D ^Smd '" ^der ^

under the conditions described in Example I and 4 Bcdingun ₄ s vufkti learned? "Tu"! ΐ "" ^{F? rmkö} A ^P _K ^Cr T

The test results are shown in Table 2 chea _n gc? üiT ^Kai " ^{SChuk mM} mchtfluonerlcr Obcrfla-

Tabcllc 2

Designation of the characteristic values

^ ΓοΑιιΓγ ^ ¹¹ ^ ' ¹ ! ^^ ¹¹¹ ^ ¹¹¹¹¹ ^ ¹¹ ^ "^ rmk ^ pVr from vi.lk-.ni- ~" wrschiedencr ν! 'search """™ ^Bcdin e ^un S <= n« learn Kaulschuk mil »i.' fluorinated surface

Attempt I.

Attempt 2

Attempt 3

Static friction coefficient 0.12

Equal friction factor 0.3

Temperature in the contact zone »vulcanized rubber / metals (" C)

Tensile strength of the vulcanized 170 rubber (kp / cm ² )

Example b

The Fkioricriing one subjected the surface of the Molded body made of vulcanized rubber, manufactured from vulcanized rubber on the basis of Natural rubber.

0.12 0.12 1.2 0.3 0.25 1.7 81 75 230 170 155 17i)

The preparation of the reagent gas as well as the lluoric-jiing the surface of the molded body made of vulcanize rubber with subsequent rinsing of the Huorierungsrcaktors and washing of the molded body vulcanized rubber was carried out analogously to Example I. The temperature was des

liquid antimony pentafluoride in the evaporator 30 ° C, the temperature in the fluorination reactor 45 ° C, the degree of exchange of the reagent gas in the fluorination reactor 20 volume / hour, the duration of the fluorination process 60 minutes, the duration of the flushing of the fluorination reactor at a temperature of 45 ° C 60 minutes.

The molded bodies made of vulcanized rubber with a fluorinated surface were subjected to a test, by looking at the coefficient of static friction on a tribometer as well as the tensile strength of the vulcanized rubber and the elongation at break. The following results were obtained (in brackets the same characteristic values are given for non-fluorinated vulcanized rubber):

Static friction coefficient 0.15 (1.0); Tensile strength of the vulcanized rubber 220 kg / cm ² ; Elongation at break 430% (460%).

Example 7

For the production of reagent gas one used an evaporator, which is a 300 mm long aluminum tube with an inner diameter of 50 mm and a wall thickness of 20 mm. To the The vaporizer had end faces on one side with a nozzle with a tube for introducing the carrier gas and on the other side a nozzle for leading out the reagent gas. On the outside surface of the evaporator was a heating element with thermal insulation arranged and built into the wall of the evaporator a resistance thermometer. At a distance of 50 mm from the end face with the nozzle for introducing the antimony pentafluoride there was in the wall of the evaporator has an opening into which a polytetrafluoroethylene capillary 0.1 min diameter that was used with a container that was liquid Containing antimony pentafluoride.

The evaporator was heated until a temperature of 160 ^° C. was reached. The carrier gas (air) was then passed through the evaporator and liquid antimony pentafluoride was introduced through the capillary in the form of a thin jet at a rate of 2 g / min. The reagent gas formed in the evaporator was fed in the form of a continuous stream to the fluorination reactor by previously passing it through an intermediate container with a capacity of 50 liters, where the reagent gas was heated to a temperature which is equal to the temperature in the fluorination reactor.

Made from vulcanized rubber based on fluororubber (copolymer of vinylidene fluoride with trifluorochloroethylene) molded bodies made of vulcanized rubber were brought into the Reactor and introduced the fluorination of the surface of the molded body made of vulcanized rubber subsequent rinsing of the reactor and washing of the molded bodies made of vulcanized rubber analogously to Example 1 through. The temperature in the fluorination reactor was 100 ° C. and the degree of exchange was Reagent gas in said reactor 20 volumes / hour, the concentration of antimony pentafluoride in the reagent gas 310 mg / 1 reagent gas, the duration of the fluorination process 15 minutes, the duration of the Flush the fluorination reactor at a temperature of 100 ° C for 30 minutes.

The molded bodies made of vulcanized rubber with a fluorinated surface were subjected to a test under the conditions described in Examples 1 and 4. The following results were obtained (the same characteristic values for non-fluorinated vulcanized rubber are given in brackets):
Static friction coefficient 0.11 (1.0); Coefficient of sliding friction 0.28 (1.5); Temperature in the contact zone "vulcanized rubber / metal" 75 ° C (19O ⁰ C); Tensile strength of the vulcanized rubber 220 kgf / cm ² (230 kgf / cm ² ).

Claims (1)

Patent claims: 1. Process for the fluorination of the surface of vulcanized rubber moldings by treatment with vaporous antimony pentafluoride mixed with a carrier gas at a temperature of 20 to 140 ° C and washing of the fluorinated surface with a 5 to 20% aqueous solution of Alkali carbonate and water, characterized in that the shaped bodies are treated with a mixture of antimony pentafluoride vapors and nitrogen or air as the inert carrier gas at a concentration of 150 to 310 mg / 1 of the antimony pentafluoride in the gas mixture in the fluorination reactor at an exchange rate of 10 to 20 volume / hour treated at a temperature of 40 to 100 ° C, wherein the current conducted to treat the shaped body flow of reaction gas is generated by continuously vaporizing a in the flow of carrier gas at a temperature of 150 to 170 ⁰ C introduced stream of antimony pentafluoride. 2, method according to claim 1, characterized in, that the flow of the reaction gas, which is passed over the shaped body for treatment is, by bubbling the carrier gas through the liquid antimony pentafluoride, which is a Has a temperature of 20 to 80 ° C is generated. 3 °