JPS5820968B2 - Method for modifying the surface of mechanical rubber products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a technique for applying a coating to a molded product of a polymeric material, and more particularly to a method for modifying the surface of a rubber product for mechanical use.

The present invention is a mechanical rubber product (so-called "slip rubber") that has a very low friction coefficient and high wear resistance as a rubber.
It can be used in the rubber industry for manufacturing.

Modified mechanical rubber products have the particular advantage of being used in movable and fixed sealing structures of various machines and equipment, as well as in bearings and their low friction sensitive units.

In this case, the working surface of the modified chemical rubber part is low friction and chemically inert, so that the adhesion of the rubber to the metal in air, vacuum and water is completely eliminated and the sealing Starting movements and disengagement are facilitated, and operation is smooth and reliable for both rotational and reciprocating movements.

By reducing wear and tear on mechanical control devices through the use of "lubricious" resins, both the reliability and sensitivity of such devices are significantly increased.

The strong hydrothermal properties of water-resistant "slip" rubbers make them essential for hermetic seals in watches and other precision instruments and equipment.

The combination of low friction and chemical inertness allows for the widespread use of "lubricious" resins in the medical field, particularly where low friction helps reduce patient pain. .

Methods of modifying the surface of mechanical rubber articles by irradiation are known (1964 U.S. Pat.
, 142, 754).

This known method improves the physico-mechanical properties of the rubber article by forming a modified layer with improved adhesion on the surface of the rubber article, compared to the surface properties of materials not treated in this way.

However, this hardly changes the anti-friction properties of the rubber.

Most similar to the present invention, both in terms of technical outline and the results obtained, is a method for modifying the surface of mechanical rubber articles, which involves treating the article with chemically active particles. and by applying a polymer layer to their surfaces (see GB 1,120,803 of 1965).

This known method does not give the desired improvement in the antifriction properties of the material, ie the wear resistance and friction coefficient.

A device for modifying the surface of mechanical rubber products is further known (1964
No. 3,142,754 of 964).

This known device cannot be used to modify the surface of mechanical rubber products in vacuum.

Similar devices for modifying mechanical rubber products are also known, which include a sealed chamber containing an electrode connected to a power source located outside the chamber. (1953, Moscow Leningr
ard, USSR Academy of Sciences
es Publishing House, D, N
, An-dreev, Organichesk
i i sinteg v lek -triches
Organ-i by kikn razriadakn
c 5yntnesis in Electri
c Disch-arges”).

This known device does not modify the surface of a large number of mechanical rubber products and at the same time form a protective film on the surface.

Another object of the present invention is to provide a method for modifying the surface of mechanical rubber articles, which method helps improve the abrasion resistance of mechanical rubber articles.

One aspect of the present invention consists essentially in a method of modifying the surface of a mechanical rubber product by treating the mechanical rubber product with chemically active particles and depositing a polymer layer on the surface of the mechanical rubber product. The product is wetted with carbon tetrafluoride and then placed in a sealed chamber evacuated to a residual pressure less than IPa, during which a glow discharge is induced in this sealed chamber and the mechanical rubber article is brought into this glow discharge state. After that, a polymer layer is deposited on the surface of the mechanical rubber product, and then the mechanical rubber product is subjected to the action of a glow discharge with a specific power of up to 0.05/c1rL3 for one hour or more. 1. A method characterized in that the method is characterized by causing the subject to undergo

The effects of each step in the method of the present invention are listed below: (1) When a rubber product is wetted with carbon tetrafluoride, the surface layer of the product is saturated with carbon tetrafluoride.

If the next step is not carried out in step 5, the carbon tetrafluoride molecules will diffuse into the rubber product or volatilize.

Due to the surface properties of rubber products (particularly the coefficient of friction when rubbed against a solid object), it remains at 7x for a while after being wetted.

(2) Treatment with chemically active particles (in the case of the present invention, by wetting with carbon tetrafluoride) without adhering a new layer of another substance to the surface layer of the rubber product. It only causes destruction or cross-linking of raw rubber,
At this stage, there are no noticeable changes in the friction coefficient or wear resistance of the product.

(3) No change occurs even during glow discharge treatment without applying carbon tetrafluoride to the surface of the rubber product.

(4) The combined effect of the steps of wetting with carbon tetrafluoride and then treating the wetted product with active particles of a gas discharge plasma is that carbon tetrafluoride molecules are grafted onto the product material. This results in the formation of a fluorocarbon polymer film on the product surface.

This formed film changes the properties of the product surface.

In other words, the coefficient of friction is significantly reduced and the wear resistance is improved. (5) The second treatment with gas discharge plasma in the final engineering section ensures a sufficiently strong bond between the surface of the rubber product and the polymer film, i.e., the polymer layer. I'll make it like that.

Furthermore, an apparatus according to the present invention is an apparatus for modifying the surface of a mechanical rubber product, which apparatus includes a sealed chamber containing an electrode connected to a power source.
It comprises a mechanical rubber product transport mechanism located directly in the interelectrode space of the sealed chamber and a drive kinematically coupled to the transport mechanism.

Preferably, the conveying mechanism is in the form of a cage, the end elements of which serve as electrodes and are interconnected by electrically insulated spokes mounted around the end elements.

It is conceivable that the electrode is provided with at least one hole.

It is also conceivable that the electrodes are arranged on a mechanical rubber article transport mechanism, which mechanism is in the form of a hollow conical platform.

Preferably, the electrode is in the form of a ring with spokes.

The present invention aids in the production of mechanical rubber products (lubricious resins) that have very low coefficients of friction and high wear resistance for rubbers, and also helps in the formation of the starting materials and in the production of mechanical rubber products. This does not change the manufacturing technology in any way.

This allows the invention to be used for the purpose of increasing the service life and increasing the reliability of machines, equipment and devices.

When a mechanical rubber product with a modified surface is used to seal a watch, it ensures water resistance for 25 years.

When surface-modified mechanical rubber products are used to seal moving assemblies of motor vehicle units, they help to double the service life of such units.

The device for modifying the surface of large mechanical rubber products comprises a sealed chamber 1, on the end face of which two current leads 2 are arranged, these current leads are placed outside the chamber 1. A drive 4 is connected to the power source 3 and is also located outside the chamber 1, which drive 4 is kinematically coupled to a mechanism 5 for transporting mechanical rubber products, which mechanism 5 is connected to the chamber 1. It is located inside 1.

The mechanism 5 is in the form of a squirrel cage, the end elements of which serve as electrodes 6, which are connected via current leads 2 to a power source 3.

The electrodes 6 are interconnected by electrically insulated spokes 7 mounted around the cage end elements.

Furthermore, the apparatus according to the method embodiment of the present invention is in chamber 1.

A vacuum pump 8 is provided for evacuating air from the machine and removing impurities from the surface of the mechanical rubber product 9 being treated, as well as a loading batch 10 and a withdrawal batch 11.

In order to adjust the rotational speed r, p, m of the drive device 4, an autotransformer 12 is configured to be electrically connected to the drive device 4.

In order to inspect the fuselage that modifies the mechanical rubber product 9,
The chamber 1 has an inspection port 13 .

The end elements of the cage serving as electrodes 6 are shown schematically in FIG.

Six holes 14 are provided in the electrodes for loading mechanical rubber articles 9 into the interelectrode spaces of chamber 1.

To modify the surface of small mechanical rubber articles 9, the apparatus shown in FIG. 3 is used.

The device comprises a sealed chamber 1, on the end of which two current leads 2 are arranged, which are connected to a power supply 3 located outside the chamber 1, and which are further connected to a power source 3 placed outside the chamber 1. It also comprises a placed drive 4 which is kinematically coupled to a mechanism 5 for transporting mechanical rubber products, which mechanism is arranged inside the chamber 1 .

The transport mechanism 5 is placed below the electrode 15 and is in the form of a hollow conical platform 16.

Furthermore, the apparatus shown here comprises a vacuum pump 8 for evacuating air from the chamber 1 and removing impurities from the surface of the mechanical rubber product 9 being treated, as well as loading means 17 and unloading means 18; These are in the form of an air chamber connected to a vacuum pump 8, which air chamber is separated from chamber 1 by gate locks 19, 20 and from the atmosphere by gate locks 21, 22.

Reloading of the mechanical rubber article 9 from the chamber 1 into the removal means 18 takes place via a port 23 provided in the center of the conical platform 16, which port can be closed by a valve 24.

In order to adjust the rotational speed r, p, m of the drive device 4, an autotransformer 12 is configured to be electrically connected to the drive device 4.

In order to inspect the process of modifying mechanical rubber products 9,
The chamber 1 has an inspection port 13 .

Electrode 1 in the shape of a ring 25 with spokes 26
5 is shown generally in FIG.

When a product is wetted with carbon tetrafluoride, those molecules penetrate the material.

This ensures an increased implantability of the polymer deposited on the article during the additional treatment in the gage discharge and thus ultimately improves the antifriction properties of the material.

A device implementing the method of the invention for modifying the surface of large mechanical rubber articles operates as follows.

- The product 9 to be treated (FIG. 1), for example a rubber gasket, is introduced into the interior of the chamber 1 via a charging batch 10 and distributed between the electrodes 6 of the mechanism 5.

In this case, the stirring device is rotated slowly in order to pre-align the hole in the batch 10 with one of the holes 14 in the electrode 6.

At this time, the charging batch is closed and the chamber is opened using the vacuum pump 8 until a pressure of 1 to 0.1 Pa is reached.
All the air is removed.

A gas discharge is then induced in the sealed chamber and at the same time the device 4 is activated.

When rotating the basket, the product to be processed moves upwards under the action of centrifugal force, then upwards under the action of gravity, and falls into the spokes under the action of gravity.

During this time, the glow discharge freely spreads over the entire volume of chamber 1.

The desired mode of agitating the rubber product for the machine is set by varying the rotational speeds r, p, m of the cage with the aid of an autotransformer 12 and monitored via an inspection port 13.

At the end of processing the mechanical rubber product 9, the power supply 3 is switched off and the chamber 1 is unsealed.

The mechanism 5 has a mechanism in which one of the holes 14 of the electrode 6 takes out the batch 11.
It will be stopped at the position that matches the hole.

Batch 11 is then opened and product 9 is removed from chamber 1.

By using the mechanism 5 to fix the chamber 1 of the device of the invention, the design of the device is simplified, the operating conditions are facilitated and the reliability is increased.

Such a device can be used to reduce the coefficient of friction and at the same time increase the wear resistance of a large number of mechanical rubber products of similar or different shapes.

A device implementing the method of the invention for modifying small mechanical rubber products operates as follows.

The product 9 to be processed, for example a toroidal rubber backing with a diameter of up to 3 millimeters, is loaded into the loading means 17 (FIG. 3).
can be placed in

Using the vacuum pump 8, the chamber 1, the loading means 17 and the unloading means 18 are heated from 1 to 0. The chamber 1 is evacuated to a pressure of IPa, and then high pressure is applied from the power source 3 to the electrode 15.
A glow discharge is generated.

The drive 4 is turned on and the platform 16 is rotated, after which the gate lock 19 communicating the loading means 17 with the chamber 1 is opened and the products 9 are loaded onto the platform 16.

When rotating the platform, the product 9 to be processed is thrown by centrifugal force against the fixed walls of the chamber 1, hits these walls, rebounds and continues these movements within the chamber 1, eventually falling onto the platform 16.

Ring 25 with electrodes 15 having spokes 26 (FIG. 4)
, so that movement of the product 9 inside the chamber 1 is not inhibited during processing.

Platform 16 (FIG. 3) with the help of autotransformer 12
By adjusting the rotational speed of the chamber 1, a mode is set in which the product 9 to be treated moves over the entire volume of the chamber 1.

It is confirmed by viewing through the inspection port 13 that the optimum mode has been reached.

The valve 24 then serves to open the port 23 of the platform 16 and the gate lock 20 serves to place the removal means 18 in communication with the chamber 1.

The product 9 is reloaded from the platform 16 into the removal means 18, after which the gate lock 20 closes while the gate lock 22 opens and serves to communicate the removal means 18 to the atmosphere.

Thereby, the treated product 9 is removed from the means 18.

The next loft of product 9 to be processed is then applied via the loading means 17 to the chamber 2 of the device and the operating cycle of the device is repeated.

The device according to the method according to the invention described above reduces the coefficient of friction and at the same time increases the wear resistance of a large number of mechanical rubber products.

For a better understanding of the invention, reference will now be made to specific examples thereof.

Example 1 The method of the invention was used to modify the surface of rubber samples based on fluororubber, butadiene-nitrile rubber, ethylene-propylene triple rubber, and fluorosiloxane rubber.

A rubber sample with size 150X150X21111 was wetted with carbon tetrafluoride.

The sample was then placed in an evacuated sealed chamber 1 to allow the carbon tetrafluoride to be drawn into the starting material and cross-linked with the polymer applied during the subsequent modification step.
(Figure 1).

A glow discharge was induced by applying the voltage required to produce a visible glow in chamber 1 to electrode 6 inside chamber 1 with the aid of power supply 3 .

When the discharge is started and the air continues to be evacuated, the pressure in chamber 1 initially increases and then gradually decreases.

In this process, chamber 1 must be evacuated in advance to a residual gas pressure below IPa in order to prevent the discharge in chamber 1 from leaving during the pressure increase due to the removal of impurities contained in the rubber. The sample was then held under glow discharge conditions for over an hour, and a layer of polymer, such as polytetrafluoroethylene, was applied to the sample by conventional means.

Finally, the product should be between 0.001 and 0.05 W/CIr
It was treated once more in a vacuum chamber by glow discharge at a specific power of L3.

In this range of specific power values of the glow discharge, the maximum effect on the rubber in question is obtained within a minimum period of time, for example after 1 to 2 hours of treatment.

Increasing the power of the glow discharge further leads to partial destruction of the surface of the sample.

The denatured sample was then removed from chamber 1.

Example 2 The method of the invention was used to modify the surface of rubber samples based on fluorocomb, butadiene-nitrile rubber, ethylene-propylene triple rubber, fluorosiloxane rubber.

A rubber sample of size 150X150X2 mir was wetted with carbon tetrafluoride and evacuated in a sealed chamber 1 in order to draw the carbon tetrafluoride into the starting material and cross-link with the polymer provided during the subsequent modification step. (
1), and a glow discharge was induced by applying to the electrodes 6 inside the chamber 1 with the aid of the power source 3 the voltage required to form a visible glow in the chamber 1.

As the discharge begins and air continues to be evacuated, the pressure in the chamber initially increases and then gradually decreases.

In order to prevent the discharge of chamber 1 from leaving during the pressure increase due to the removal of impurities contained in the rubber in this process, chamber 1 must be evacuated in advance to a residual gas pressure below IPa, The sample was then held under glow discharge conditions for over an hour and a layer of polymer such as polytetrafluoroethylene was applied to the sample by conventional means.

Finally, rubber products are 0.001 to 0.05W/Cr
It was treated once more in a vacuum chamber by glow discharge at a specific power of 113.

In this range of specific power values of the glow discharge, the maximum effect on the rubber in question is obtained within a minimum period of time, for example after 1 to 2 hours of treatment.

Increasing the power of the glow discharge further will result in partial destruction of the sample surface.

The denatured sample was then removed from chamber 1.

The abrasion resistance and coefficient of friction of the modified samples were determined in a conventional abrasion tester using stainless steel ball indentations of 0.5 bar diameter.

The frictional properties of various rubbers before and after modification by the method of the invention and by known methods are listed in the table below.

These measured values indicate that the indenter is 0.1r' relative to the sample.
The sample unit slides at a speed of 11/s and has 4 sample units.
It was obtained in a state where it was loaded at 0x103Pa.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of an apparatus for carrying out the method of the present invention for modifying the surface of large mechanical rubber products, and Figure 2 is a
3 is a longitudinal sectional view of the device according to the method of the invention for modifying the surface of small mechanical rubber products, and FIG. 4 is a general view of the end element along the line IV- IV
FIG. 3 is a general view of the electrode along the line; 1... Sealed chamber, 2... Current lead, 3... Power supply, 4... Drive device, 5
...Mechanism for transporting mechanical rubber products, 6...
...Electrode, 7...Spoke, 8...
Vacuum pump, 9... Mechanical rubber products, 10...
... Loading batch, 11 ... Removal batch, 12 ... Single-turn transformer, 13 ... Inspection port, 14 ... Hole, 15. ...electrode, 16
...Platform, 17...Loading means, 18...Ejection means, 19, 20゜21
．． 22...Gate lock, 23...Boat, 24...Valve, 25...Ring,
26...Spoke.

Claims (1)

[Claims] 1. A method of modifying the surface of mechanical rubber articles 9 by subjecting them to chemically active particles and depositing a polymer layer on their surface, in which said mechanical rubber articles 9 are tetrafluorinated. Wet with carbon and IPa
in a vacuum with a lower residual pressure, the mechanical rubber article 9 is subjected to the action of chemically active particles in the form of a glow discharge and kept in the glow discharge for more than one hour; A method characterized in that, after application of the polymer layer, the mechanical rubber article is subjected to a glow discharge having a specific power of up to 0.05 W/cnL'' for at least one hour.