WO2007085614A2 - Device and method for the surface treatment of rollers in the paper industry - Google Patents

Abstract

The invention relates to a device for the ion implantation in roller surfaces for the production of paper, comprising at least one ion source, an accelerator, a vacuum chamber and a deviation device, at least a part of the roller surface to be treated being received in the vacuum chamber. The invention is characterized in that foreign ions are inserted into the roller surface in such a manner that a strong adherence of materials, which are treated with the roller, is largely prevented.

Description

 Apparatus and method for surface treatment of rolls in the paper industry

The present invention relates to an apparatus and a method for foreign ion implantation in surfaces of rolls in the paper industry. Furthermore, the invention also relates to the use of a corresponding device or method for foreign ion implantation in rolls produced on surfaces and their use for the production of paper.

Devices and methods for foreign ion implantation in surfaces of components in the paper industry are known in the art. Thus, for example, the German Utility Model Publication DE 200 21 552 describes a screen basket, in particular for a paper and board machine, in which foreign ions are stored in the surface of the basket to increase the service life. As foreign ions in this case only the hardness of the treated material increasing substances such as nitrogen, carbon, molybdenum, boron, tungsten or titanium are proposed.

Increasing papermaking speeds, water loop closures, higher temperatures used in the dryer section, higher pressures applied in the press section, and the abrasive fillers used in the paper as it is being manufactured, are increasing the demands on the rollers and their surfaces required for manufacture. In particular, there is an increased load on the roll surface with respect to corrosion, increased abrasion and contamination from operating and processing materials. Especially in recent years, the problem of production disturbances caused by the so-called organic contaminants has become increasingly topical. The deposits include biological and non-biological materials of organic and inorganic origin. It is to be expected during the production of wood-containing and waste paper-containing papers by the neutral driving style and the tightly closed water cycles with more deposits on the rollers, as in the production of wood-free papers, especially when using dry pulp.

Increased constriction of the water cycles in the paper mills also leads to the accumulation of dissolved and colloidal substances. Although these can interact with cationic auxiliaries during the production process, agglomerates or coacervates can also be strongly formed.

The most common causes of production disruptions to be addressed in the chemical-physical papermaking process are considered below:

Waste paper consumption in Europe has almost doubled in the past 10 years to about 11 million tons per year and is still on the rise. Above all, deposits are caused by self-adhesive tapes, the adhesive backing of books, brochures and paraffin-coated papers, and they have a noticeably sticky character.

Increasing the paper machine speed and at the same time increasing the filler content on eg newsprint paper from 10% to 20% ash content, the basis weight has been reduced from 52 g / m ² in 1975 to 42.5 g / m ² today. This contributes to increasing the risk of demolition and to difficult separation of the paper sheet from the central and transfer or guide roller. Due to the increased filler content, there is also a high water cycle load, which in turn contributes to increased deposit formation. In addition, the strength of the paper is reduced. The constriction of the water cycles leads to an increase in the temperature in the material system and thus to an increased extraction of dissolved and colloidally dissolved substances, which in turn form further interfering substances and can lead to production disruptions on the paper machine. Due to the accumulation of impurities, it is necessary to add further auxiliaries. The addition of additional aids can cause additional deposits.

With the neutral or alkaline driving style, the papermaker has an inexpensive pigment - the calcium carbonate - in the mass, as well as for brushing available. In addition, the use of this material shows a quality improvement of the paper in terms of aging resistance, higher whiteness and higher opacity.

However, calcium carbonate can only be used in a neutral or pseudo-neutral mode of operation and the addition of excess aluminum sulphate leads to gypsum formation, dissolved calcium carbonate or carbon dioxide formation in the material system and thus to flotation effects, which in turn contribute to production disruptions. With increasing use of calcium carbonate, whether in bulk or by the reprocessing line or returned coating color, the neutral driving at elevated pH is required. In the pH range of 6.5 and 7.2, however, the tendency for the deposition of sticky substances is particularly strong. In addition, the carbonate hardness increases, which in turn promotes the deposition tendency of resins from TMP and pulp. It is therefore very important in this procedure to ensure that the negatively charged resin particles and anionic impurities in the increased pH range are well bonded to the fiber, otherwise must be expected with increased problems, especially on the roll surfaces.

From studies it is known that the contamination of central rollers and the associated wet felts caused mainly by ingredients such as resins, waxes and binder constituents from the waste paper, or from the Streicherei Committee and recycled coating residues - A -

become. The higher the affinity of the roll cover materials to these "interfering substances", the more likely it is that the roll surfaces will be more or less heavily coated.

The paper machine speed has z. B. in newsprint paper since 1950 more than tripled. At high paper machine speeds, turbulences increasingly occur in the material systems which, after release of dissolved gases, cause unwanted flotation of the "disturbing" substances and resin particles, causing their kinetic energy to contact the surfaces of various machine parts and form agglomerates there. After reaching a certain size of these deposits they are discharged with the paper web and can in turn lead to disturbances on the rollers, felts and sieves.

With the plastic roll covers used, which are made of the matrix resin / fillers, the speed of high speed newsprint paper machines with 100% used paper was limited to 1500 m / min because the release properties were too weak and thus the paper web train was too large. The further development led to ceramic coverings, which have a very good paper sheet delivery and allowed an increase of the paper machine speed by up to 20%. However, they once again encountered limits that were as follows: a) No constant adhesion of the ceramic material (500 μ) to the roll core due to undercutting or insufficient core bonding. b) Decreasing paper sheet output due to abrasion and laying of the cover material (too high a pull = paper web breaks at maximum speed).

Disturbing material or deposits generally on rollers include biological and non-biological deposits of organic and inorganic origin. Table 1 shows the classification, which is equivalent to "interfering substances":

Table 1

The resin particles present in 1-5% pulp and wood pulp may, by reason of their nature, agglomerate into larger sticky agglomerates and deposit in the system, as already discussed. This is called harmful resin or "pitch".

Adhesive contaminants are generally known by the name of stickies and include sticky particles as they are directly present in the waste paper. The origin of this has already been described. As more and more waste paper is used in a wide range of grades and waste paper consumption is increasing, the paper industry will face more adhesive contaminants in the future.

Plastic binders or "Wight Pitch" are disturbing deposits in the production of coated paper, which from the plastic binder as an agglomerate stand. The plastic binder comes here from the Streicherei Committee or from the coating color return. The disturbing fabric "Wight Pitch" is found mainly at the central, transfer and guide rollers, which is intercepted by the scraper system.It is very strong adhesive and usually does not look "white", but has a brown to gray color.

Coacervates are the reaction products of cationic and anionic polyelectrolyte molecules.

By too concentrated dosage and unwanted interactions of the cationic and anionic aids, as well as by partial flocculation arise agglomerates in particular of these tools. The partial flocculations are formed by shock-like addition of auxiliaries and lead to agglomeration and fiber spinning. In summary, the classification of "interfering substances" is shown in Table 1.

For this reason, one uses today u. a. only mechanical aids, by trying to remove the deposited on the rollers contaminants by means of scraper. The contaminants also accumulate on the dryer screens of the dryer section. There cleaning units are used by means of high pressure water to keep the screens clean. On the one hand, no scraper units can be attached to rolls in the dryer section, on the other hand, in the warm or hot environment (about 100 ° C), the plastic deposits can not be eliminated mechanically. Thus, these accumulate in large quantities on the outer screen guide rollers and are thrown off again and again by the high centrifugal force, whereby production disturbances arise. Here, a corrosion-free and repelling roller would be necessary.

However, the high-pressure water purifiers bring so much moisture onto the roll surfaces that they very quickly corrode due to the existing heat in the dryer section. One is very aware of the difficult situation and works under heavy production pressure, whereby one can not get to the root cause of the actual causes, in order not to let emerge the occurring errors in the first place. The current papermaking process in Germany is characterized by a high use of waste paper, a growing use of calcium carbonate as a paper filler and coating pigment, an extensive conversion to a process procedure in the neutral or weakly alkaline pH range with predominantly adapted to this pH range polymeric chemical adjuvant systems, constricted water cycles with higher process temperatures, and the tendency for high levels of uncharged and anionic contaminants.

These paper and process factors place high demands on the surface materials of press rolls in paper machines and can lead to increased deposits of hydrophobic and adhesive contaminants on the press roll surfaces, the paper-contacting guide rolls and the dry wire guide rolls, thereby causing production disruptions, paper web breaks or paper machine downtimes high cost level.

The traditional granite press roll with its heterogeneous material structure generally shows good and stable paper web delivery even with variable production conditions with a very low tendency to fouling. Due to the high technological development in the papermaking process and the increase of the paper machine speed in higher temperature ranges, the granite roller is no longer usable due to the mechanical and thermal load capacity for safety reasons, even prohibited in Scandinavia.

Among other things, these requirements result in the requirement to provide roll surfaces which, in addition to high corrosion resistance, have a better abrasion behavior, ie less wear and whose surface properties have a different adhesion behavior with respect to the material to be processed. Furthermore, as far as possible, the given roughness of the roll surface should remain and the properties during paper sheet delivery in the production process should be improved. However, it also becomes clear between the Depending on the application focus in the manufacturing process different combinations of requirements must be observed.

There is also a desire to provide at least approximately such ratios as the granite roll surface presents during the paper process, i. H. the further development of paper-contacting roll surfaces, which have the same effect of stable paper web delivery and low tendency to fouling.

It should be ensured that correlation of surface topography and wettability characteristics of roll covers is ensured to assure paper machine operator trouble-free web sheet delivery.

The object of the present invention is achieved by a device according to claim 1. Furthermore, the object is achieved by a process for producing a surface-treated roll according to claim 11, by a roll according to claim 14 and the use of such a roll according to claim 19 for the production of paper.

Preferred embodiments of the device, the method, the roller and their use are the subject of the respective subclaims.

The inventive device for ion implantation in surfaces of

Rolls for papermaking comprise at least an ion source, an accelerator, a vacuum chamber and a deflection device. The vacuum chamber is designed such that at least a portion of the roll surface to be treated is received. The device according to the invention is characterized in that foreign ions are incorporated in the roll surface in such a way that a lasting adhesion of material, which is processed with the roll, is largely prevented.

In this case, ions which are selected from a group which, for example, nitrogen, carbonyl, are understood as foreign ions. fabric, molybdenum, boron, tungsten, titanium, argon, nickel, chromium, copper, zirconium, vanadium, yttrium, aluminum, nitrite-forming elements, combinations thereof, and the like.

It goes without saying that it is also within the meaning of the present invention that further ions, which are not listed above, can be part of the foreign ions in order to be stored in a roll surface of a paper-making roll by means of the device described above.

As the roll surface, not only the outermost roll boundary layer is considered according to the present invention. Rather, the surface is also understood to be an intended layer thickness of the outer roller region, which is between 0 μm and 1000 μm, preferably between 0 μm and 500 μm, and in particular smaller than 10 μm.

The roller surface is made according to a particularly preferred embodiment of a material having at least one component selected from a group of materials, in particular materials such as iron, nickel, chromium, copper, combinations thereof, in particular alloys such as stainless steels and like that.

The roll surface can also comprise plastics, such as, for example, polyurethane, polycarbonates, polyethylene, in particular of high density, polymethyl methacrylate, polystyrene, fiber-reinforced plastics, combinations thereof and the like.

The combination of various materials, such as metals and plastics, as well as ceramics, ceramic composites and composites of the general nature of the various materials can form the basis of a roll surface.

According to the present invention, the foreign ions are provided with a device for ion implantation of the surface of rolls for the papermaking industry. embedded with a penetration depth, which is between O .mu.m and 1000 .mu.m, preferably between 0 .mu.m and 500 .mu.m and in particular less than 10 microns.

The ions, in particular the foreign ions, are obtained according to a further particularly preferred embodiment by means of a method in which e.g. By gas discharge, a plasma of the corresponding ion is generated or provided by means of arc, eddy current heating or cathode sputtering.

According to another particularly preferred embodiment, the present ion implantation apparatus provides a bias voltage between the ion source and the roller surface which is between 1000 V and 1500 V, preferably between 1100 V and 1200 V. In ion implantation, the ions preferably have an energy which, according to a particular preferred embodiment, is between 10 eV and 1000 keV, in particular about 200 keV. The treated surfaces of rolls for papermaking, according to the present invention, in particular have a dose of ions which is between 10 ¹⁰ cm ^"2 and 10 ²⁰ cm ^{" 2} . According to a further particularly preferred embodiment, the dose is between 10 ¹³ cm ^"2 and 10 ¹⁶ cm ^{" 2} .

By a corresponding surface treatment of the rolls for papermaking, according to the present invention, a property of the roll surface is selected which is selected from a group of properties including electrical resistance, hardness, friction, wear, surface energy, surface energy density, surface energy Wetting behavior, the surface tension, the polarity, the adhesion, combinations thereof and the like.

According to a particularly preferred embodiment, the ion implantation in the surface of papermaking rolls provides a roll surface that is substantially self-cleaning. As a self-cleaning here is a surface property understood that at least partially reduces or prevents the adhesion of foreign materials to the surface.

This adhesion, in accordance with the understanding of the present invention, i.a. by adhesion forces (attachment forces), which act between the molecules of two bodies and lead to a mutual attraction. According to the understanding, adhesion forces act between solid, solid and liquid as well as between solid and gaseous bodies.

Self-cleaning is also understood to mean a surface property for rolls for papermaking, which can in particular largely dispense with mechanical cleaning during the production process.

It should be noted, however, that despite a corresponding treated surface, it can not be completely ruled out that adhesion of foreign material to a possibly limited extent takes place at least for a limited time, so that it is not ruled out that a correspondingly surface-treated roller will nevertheless be mechanical

Cleaning devices, in particular for ensuring the continuous manufacturing process, having.

The invention also claims a method for producing a surface-treated roll comprising the steps of: producing a directed ion beam and implanting a predetermined amount of at least one ion species in a given surface of a roll for the production of paper.

It is within the meaning of the present invention that, according to the embodiments of the device, both different types of ions and different amounts of ions per surface unit are used.

By means of this treatment, according to the invention, a surface is obtained whose properties largely prevent, in particular, permanent adhesion of materials which are processed with the roller. Such a roll surface can be described as self-cleaning and serves in particular special to improve the maintenance and service costs for the operation of such a roller.

The present invention also encompasses the papermaking roll produced by the apparatus and / or method, in the surface of which at least portions of foreign ions are incorporated. The storage takes place according to the invention in such a way that a permanent adhesion of materials which are processed with the roller is largely prevented.

In particular, according to the present invention, the specific surface properties of the roll, in particular the adhesion / adhesion force with respect to the materials to be processed, are changed in such a way that the repulsive forces exceed the attractive forces by a predetermined amount.

It is also within the meaning of a particularly preferred embodiment of the present invention that the type and amount of ions implanted in the surface of the roller in the axial direction of extension of the roller is different. In this way, in particular the edge regions of a correspondingly treated roll surface can be changed. Thus, for example, the surface portions of the material to be processed at least temporarily in contact with each other so changes in their surface properties that adhesion at least temporarily prevented or at least reduced. This can be done by the type and amount of implanted foreign ions in this area is performed differently to the remaining areas, in particular for the papermaking both the drive side, and the leader side edge region of the roller should be treated accordingly.

According to the invention, the rolls produced by the process or by the apparatus are used for use in papermaking, in particular as guide rolls in the wire, press and / or dryer section of a paper machine. The use as press rolls, as central press rolls, is within the meaning of the present invention. Furthermore, a Such roller can also be used as an embossing roll or as a calender roll, but in particular also as a coated embossing roll or as a corrugating roll.

Investigations show that hydrophilic roll surfaces have a higher tendency to deposit with respect to different kinds of water glass. On the other hand, hydrophobic impurities are deposited to a lesser extent on hydrophilic surfaces. The ceramic surfaces have surface structures that favor water glass deposits.

Since water glass deposit tendencies intensify (excess water glass from the insert for buffering the bleaching agent in the pulp), it is natural to use the current ceramic rollers in use. B. with hydrophobic particles such. B. Teflon to provide.

An essential conclusion of the investigations is that a detailed characterization, i. H. Determination and assessment of surface topography necessary to derive trend statements on wettability and deposit propensity of roll surfaces.

From this, roller surfaces should be treated with the ion implantation, since u. a. sealed ceramic surfaces (Teflon) better repel hydrophobic materials. In addition, the pore distribution and pore maintenance as well as texture retention of the surface is necessary to ensure a durable paper sheet delivery to the rolls. In the case of ion implantation, this is achieved by virtue of the structural change in that the cover can be made more abrasion-resistant and structure-preserving.

For the optimization of new high-performance press roll and guide roll covers with regard to trouble-free paper release behavior and minimized deposition affinity, all relevant physico-chemical and process engineering factors should be evaluated. The existing material selection and the reference surface finishing result in great possibilities for optimization. Here, the should optimal surface to the best paper sheet dispensing property are generated.

The ion implantation contributes to maintain this optimal surface during the paper production process and thus to meet the requirements of the practice. By these measures one avoids production disturbances and down times, whereby the higher expenditure of the coating amplification by the cost reductions (paper machine stoppages) is compensated.

In the following, the invention will be explained with reference to individual examples, it being understood in the sense of the present invention that the scope of the claimed subject matter is not thereby limited. It is rather in the sense of the present invention that deviations and changes of the following embodiments are also covered by the subject matter of the invention.

1 shows a diagram in which the hardness or the friction of steel is shown as a function of the foreign ions.

Fig. 2 is a graph showing the abrasion over time of untreated and treated aluminum.

3 shows the influence of yttrium implantation on the oxidation behavior of stainless steel.

Ion implantation is a special process for introducing foreign atoms into a solid. In this process, ions are shot in vacuo into a solid, the ions in an ion source being obtained from gaseous, liquid and solid substances. By means of an ion bombardment, it is possible to change a large number of properties of a solid surface or a layer close to the surface.

Fig. 1 shows the change in hardness (left) and friction (right) as a function of the dose of argon ions in the surface. Thus, the hardness of steel increases through the implantation of nitrogen, argon, boron and carbon ions. In Fig. 1 as an example the increase of the micro-raw hardness and the friction coefficient (lower line with Δ-sign) after the bombardment of steel with argon ions is plotted. The increase here can be more than the factor 2 or 3.

Also shown is the change in microhardness (top line with O sign) and friction as a function of dose for a 40 keV Ar imolation in steel.

It should be noted that nitrogen in particular increases the hardness of steel due to radiation damage and the formation of nitrides. The Vickery hardness of steel can be increased by bombardment with 10 ¹⁷ cm ^"2 eg from 300 kg mm ^{" 2} to 400 kg mm ^"2 .

In Fig. 2, the reduction of abrasion in implanted aluminum is shown.

This shows that the abrasion depends on the hardness of the material and the friction. It should be noted, however, that the implantation of metallic and non-metallic ions has a major influence on the coefficient of friction. In this case, a dependence on the type of ion is probably given by influences of the implanted ions on the oxidation behavior. In part, the effect of implantation could cause better lubrication through chemical alteration of the surface.

With ion implantation, surface finishing can also be performed when using ions that also prevent and reduce corrosion, such as nickel or chromium, as an alloying additive

Stole. In addition, the implantation is particularly suitable for the methodological investigation of corrosion mechanisms, since it offers the possibility to introduce virtually any substance in a known concentration and without changing the grain boundaries. Corrosion is an extremely complex process which, in addition to the electrochemical properties of the metal components and the oxidant, also depends on grain boundaries and grain boundary diffusion, stress, temperature and ambient atmosphere. Extensive studies on the oxidation of titanium and stainless steel were conducted. 10 different types of ions were tested for their antioxidant activity. After implantation, the samples were oxidized in oxygen dry for 25-30 min. It was generally found that the oxidation effect was reduced or prevented. Similar studies were carried out for aluminum. The oxidation follows in this case the Wagner-Hauffe rule, ie the thickness of the oxide is proportional to the root of the time (diffusion-limited oxidation).

In the case of chromium, it was found that primarily radiation damage determines the oxidation behavior of implanted layers. In the case of nickel, radiation damage has a major influence on the oxidation behavior, besides, the different atomic radius in particular also has an effect. Further experiments were carried out with copper and zirconium. With zirconium, all implanted elements increase the oxidation rate down to the transition elements (Fe, Ni, Cr). Has proven itself, for example, the implantation of yttrium in stainless steel to prevent oxidation at high temperatures. For this purpose, ion implantation is particularly suitable since in homogeneous alloys the hardness and toughness are likely to be low due to the deposition of yttrium at grain boundaries.

This type of implantation is of particular interest for roll surfaces in the dryer section of a paper machine.

Even studies with yttrium show a significant influence on the surface properties. For this purpose, at the dose of 3.5 × 10 ¹⁵ cm ^-2 , at energies between 80 and 410 keV, a layer of 0.2 mm thickness was doped as homogeneously as possible. The increase in weight due to oxidation is highest for the unalloyed steel and smallest for the implanted samples. At 800 ^° C. and 850 ^° C., the passivating effect of yttrium is even more pronounced. Fig. 3 shows the influence of yttrium implantation with a dose of 3.5 x 10 ¹⁵ cm ^"2 on the oxidation behavior of stainless steel in CO ₂ atmosphere at 700 ⁰ C compared to alloyed samples.

The surface energy can also be changed by the implantation. In industry, metallic surfaces are treated with vacuum plasma technology. By altering the molecular structure, one is able to influence the surface properties. The treatment in turbulent plasma does not limit the geometry of the workpieces.

It has been found that on chromed surfaces wear, anti-adhesion, corrosion and friction change positively. This agrees with the aforementioned properties. The surface energy of a chromium layer is about 24 mN / m, divided into 7 mN / m dispersively and 17 mN / m polar. Treatment with ion implantation drops the polar value to almost 0 mN / m. This thus results in a hydrophobic surface which repels the "interfering substances" during the paper production By this means one can keep the current pollution process to the rolls in a paper machine within limits, since the temperature control during the turbulent plasma between 50 ⁰ C -.. 480 ⁰ C can be controlled, even the processing of thermoplastic materials is also possible.

In the area of surface modification of polymers and ceramics, ion implantation offers advantages over other surface treatment methods, such as low process temperatures and the possibility of combining any ions and substrates.

The disadvantage may be that this technique over others

Surface treatment method has a low modified layer thickness. When implanted in plastics with energy up to 200 keV and an atomic mass of ions greater than 10, a projected range of less than 1 μm results. The change in properties of 10 ¹³ to 10 ¹⁶ ion-implanted plastic surfaces was investigated with a view to industrial application in semiconductor fabrication technology. Problems arise, for example, by static charge, particle generation by mechanical abrasion and outgassing from plastics. Boron, nitrogen, argon, chromium and arsenic ions having an energy of up to 200 keV and doses of 10 ¹³ cm ² to 10 ¹⁶ cm ^{2 were} implanted to produce a functional surface layer. The plastics studied were polycarbonate (PC), high density polyethylene (PE-HD), polymethylmethacrylate (PMMA) and polystyrene (PS). One focus is polycarbonate due to the wider use of silicon wafers and mask boxes. The focus of the investigations was the change of the electrical resistance and the mechanical properties, such as hardness, friction and wear. In addition, the wetting of the modified surface and the change in the outgassing behavior were investigated by the implantation.

The implantation resulted in the formation of a hard surface layer in all the plastics investigated with an increase of up to five times the microhardness. The formation of the hard layer is due to a change in stoichiometry due to outgassing of molecules and fragments and to the concomitant densification of the material by crosslinking during implantation. There is approximately a doubling of the carbon content and a halving of the hydrogen content. This creates an amorphous hydrocarbon layer. PC resistivity is reduced by up to 12 orders of magnitude. The increased conductivity is due to a modification of the structure and composition caused by the energy introduced during ion bombardment. The reduction in electrical resistance is not proportional to the total energy transfer, but increases with increasing electronic energy output. The wear of PE-HD is reduced to almost zero for a dose starting at 1x10 ¹⁴ cm ^"2 at 200 keV, which also results in a reduction in the coefficient of friction, which is due to a reduction in adhesive behavior combined with a reduction in the contact area between material The tribological investigations show that a very good reduction of wear can be achieved by ion implantation, but also Problems can arise due to the combination of a hard layer with a soft substrate.

The surface wetting of plastics can also be improved by implantation. A reduction in the contact angle from 84 ° to 62 ° for PC was measured, associated with an increase in the polar portion of the surface energy. By investigating the outgassing behavior of PE-HD, it has been shown that the atomic mass outgassing can be reduced from 1 to 600, whereby the condensed layer on the surface reduces the outdiffusion of short- and long-chain molecules. With respect to future applications, ion-implanted plastics offer the advantage that, by ion bombardment, simultaneously different surface properties, such as e.g. mechanical and electrical properties, can be modified.

Application examples from the paper industry

Due to the high amount of dirt accumulated, especially in the waste paper processing area, deposits in the wet part occur on roll surfaces and destruction due to aggressive abrasion. The increasingly intensive closed circuit causes the white water to salinize, this supports the corrosion on the rollers. The dirt is rejected by a hydrophobic roller surface. Higher corrosion resistance reduces the rust tendency and a harder roll surface counteracts the abrasion.

The force of the paper removal from the roll surface at the central press roll, where the paper is transferred to the 4th press or dryer section in free draw, increases with increasing speed in the square. These

Withdrawal forces can be altered by influencing the roll surface energy, which reduces the pull-off forces and thus maintains a residual expansion in the paper sheet for subsequent further processing. During papermaking, during the drying process, the dryer fabrics and, moreover, the guide rolls are soiled by latex binders, book back adhesives, hotmelts, and other adhesive materials. The ion-implanted roller surface would either not accept the abovementioned materials due to its strongly repellent behavior, or it could be removed more easily by a scraper. Corrosion resistance is a recurrent theme in dry wire guide rollers. Ion implantation - a change in the molecular structure - influences the surface properties of a material. This is not a coating, but a vacuum plasma technology with the benefit of additional ion implantation.

The most successful method is the doping of nitrogen atoms, which positively alters the surface in terms of wear, non-stick properties and corrosion. The wear resistance increases due to hardening of the roll surface. Corrosion is determined by the oxidation behavior of the material surface. Ion implantation significantly modifies this oxidation behavior and corrosion resistance is determined solely by the implanted layer thickness.

It is particularly important that the surface energy of a material is influenced by the implantation. It was found that the surface energy of a chromium layer of about 24 mN / m, divided into 7 mN / m dispersively and 17 mN / m polar, after the ion implantation in the polar

Changed value to almost 0 mN / m. This means a hydrophobic surface which, in turn, would promote paper sheet delivery and limit the contamination process on rolls in a paper machine.

Not only the three application areas presented in a paper machine would be useful, but embossing, hard calender rolls and drying cylinder in the paper and corrugating rolls in the corrugated industry also considered.

Further possibilities are that a base layer, such as e.g. Chrome, tungsten carbide or ceramic applies and this layer refined with implanted layers.

For these procedures u. a. closed spray booths used, so that the application of both methods is possible within a cabin.

Claims

claims 1. Apparatus for ion implantation in surfaces of rolls for papermaking with at least one ion source, an accelerator, a vacuum chamber and a deflection device, wherein in the vacuum chamber at least part of the roller surface to be treated is accommodated, characterized in that Foreign ions are incorporated in the roll surface in such a way that a substantial adhesion of materials which are processed with the roller is largely prevented. 2. Device for surface treatment according to claim 1, characterized in that the foreign ions are selected from a group of ions including nitrogen, carbon, molybdenum, boron, tungsten, titanium, argon, nickel, chromium, copper, zirconium, vanadium, yttrium, Aluminum ions, nitrite-forming elements, combinations thereof, and the like. 3. Surface treatment device according to one of the preceding claims, characterized in that the roll surface has at least one constituent selected from a group of materials including, but not limited to, metals such as, in particular, iron, nickel, chromium, copper, combinations thereof. special alloys such as stainless steels and the like, plastics such as in particular polyurethane, polycarbonates, especially high density polyethylene, polymethyl methacrylate, polystyrene, fiber reinforced plastics, combinations thereof and the like, composites, ceramics, ceramic composites, combinations of the various materials and the like. 4. Surface treatment device according to one of the preceding claims, characterized in that the ions preferably have a penetration depth into the roll surface which is between 0 μm and 1000 μm, preferably between 0.1 μm and 500 μm and in particular smaller than 10 μm. 5. Surface treatment device according to one of the preceding claims, characterized in that the ions are recovered by a method selected from a group of methods, which are generated by gas discharge generated plasma, electric arc, Wirbelstromerhitzung, sputtering, combinations thereof, and the like. 6. Surface treatment device according to one of the preceding claims, characterized in that the bias voltage between ion source and roll surface is between 1000 V and 1500 V, preferably between 1100 V and 1200 V. 7. Surface treatment device according to one of the preceding claims, characterized in that the energy of the ions is between 10 eV and 1000 keV, in particular »about 200 keV. 8. Surface treatment device according to one of the preceding claims, characterized in that the dose of ions to the surface treatment of between 10 ¹⁰ cm ^-2 and 10 ²⁰ cm ^"2 and in particular between 10 ^{13 cm"} is ² and 10 ¹⁶ cm ^"2. 9. Surface treatment device according to one of the preceding claims, characterized in that at least one property selected from a group of properties including electrical resistance, hardness, friction, wear, surface energy, surface energy density, wetting behavior, surface tension, polarity, adhesion, combinations thereof and the like. 10.Vorrichtung for surface treatment according to one of the preceding claims, characterized in that the roll surface is substantially self-cleaning. 11.A method for ion implantation in surfaces of a roll for producing paper, comprising the steps of: Generation of a directed ion beam; Implanting a predetermined amount of at least one kind of ions in a given surface of a roll for the production of paper; 12. The method according to claim 11, characterized in that the surface of the treated roll has a predetermined property, which in particular largely prevents permanent adhesion of materials which are processed with the roll. 13. The method according to any one of claims 11 to 12, characterized in that a surface treatment device according to at least one of claims 1 to 10 is used. 14. Roller for papermaking, in whose surface at least partially foreign ions are incorporated in such a way that a permanent adhesion of materials which are processed with the roller, is largely prevented. 15. Roller according to claim 14, characterized in that by incorporating a predetermined amount of at least one Fremdions, the specific surface properties of the roller, in particular the adhesion is changed with respect to the material to be processed. 16. Roller according to at least one of claims 14 or 15, characterized in that the nature and quantity of the implanted in the surface of the roller lo-> NEN in the axial direction of extension of the roller is different. 17. Roller according to at least one of claims 14 to 16, characterized in that in particular, the roll surface in the edge region, which at least temporarily comes into contact with an outer edge region of the processing material, having a different amount and / or type of foreign ions. 18. Roller according to at least one of claims 14 to 17, characterized in that it is produced with a device according to one of claims 1 to 10 and / or a method according to at least one of claims 11 to 13. 19. Use of a roll according to one of the preceding claims for use in the paper industry, in particular as a guide roll in the wire, press and / or dryer section of a paper machine, as a press roll, as a central press roll, as an embossing roll, in particular as a coated embossing roll, as a calender roll, as corrugating roll, combinations thereof and the like.