JP5557208B2 - Contaminated objects, apparatus for cleaning contaminated objects with dry ice, methods for removing contaminants, and use of functional coatings - Google Patents

Description

  The present invention relates to a method for removing contaminants by injecting an injection medium onto a contaminated part of an object coated with a functional layer. The jetting medium is jetted onto the contaminants by a gas flow, and the jetting medium consists of dry ice or contains dry ice. The present invention further provides that the contaminated object having a functional layer, which can be cleaned very well by the method according to the present invention, and the contaminated object that can be carried out very effectively by dry ice are treated with dry ice. The present invention relates to an apparatus for cleaning. The invention further relates to the use of a functional coating to delay the temperature equilibrium between the contaminant and the object when the object contaminant is removed with dry ice. Thereby, the method according to the invention can be carried out very well.

  In many technical fields, the tools, production equipment or auxiliary equipment used are regularly contaminated by materials used, such as paints, adhesives, processing aids or dough and fats and oils. Such materials often burn or crack on the surface of the device, thereby creating a layer of contaminants that are extremely stubborn and easy to adhere.

  A very effective method for removing (cleaning) such partially stubborn contaminants (dirt) is dry ice cleaning. In this method, the cleaning action is based on various mechanical and physical factors. Here, in addition to (i) mechanical wear caused by impinging dry ice against contaminants, (ii) large temperature difference with respect to the base layer caused by the low temperature of dry ice (at about −78 ° C. at atmospheric pressure) In relation to (thermal stress), weakening contaminants at low temperatures; (iii) additional cooling by sublimation in some cases; and (iv) rapid volume of dry ice during sublimation. Increase mechanical action.

  In the usual manner, dry ice pellets are jetted from the jetting device into the contaminated area of the object to be cleaned by means of a gas flow with a velocity higher than 150 m / s, preferably 300 m / s. The size of the injection material in the case of pellets is about 3 mm in diameter, and the length is not fixed. Additional equipment can reduce the size of the pellets. A typical injection angle with respect to the contaminant surface is about 60-90 °.

  The method of removing contaminants using dry ice (dry ice cleaning), which is common today, has a series of drawbacks. If the gas flow is large and the flow rate of dry ice particles is high, a very loud noise of 110 dB (A) or more is generated.

  A number of reports have been made on automatic cleaning of molds so that noise can be suppressed by storing them in capsules, but this has not been recognized in the market so far. In the case of automatic mold cleaning with a standard injection pipe (when installed in a large machine), it is difficult to clean undercuts that are difficult or difficult to clean, especially when the surface of the parts is complex, due to the limited movement of the mechanism. A shadow part occurs. This drawback can be mitigated by hand, but the cleaning result is only slightly improved, despite the very cumbersome work. Thus, today, complex equipment or dirty parts of complex equipment are typically disassembled for manual cleaning to obtain an optimal cleaning effect. In addition, contaminants with good thermal conductivity make cleaning difficult. This is because the temperature difference effect of the dry ice cleaning action is reduced by rapid temperature equilibrium. The same is true for small heat capacity objects or object surfaces with good heat transfer, for example thin objects that are rapidly cooled. In this specification, heat conduction is understood to be heat conductivity.

  Furthermore, contaminants with a low cohesive force have no cleaning effect depending on the object surface. This is because the contaminant becomes more fragile than the delamination action at the interface between the object and the contaminant, thus leaving the remainder of the contaminant attached. For example, the paint that is overcoated many times by the paint apparatus is removed one after another for each layer.

  Due to the high pressure of the carrier gas stream used, not only contaminants, but also the objects to be cleaned are exposed to high mechanical loads. This load is even greater when external water effects such as high humidity cause water in the ice mold to be sprayed onto the object with dry ice, thereby creating dents and defects on the surface to be cleaned. become. The large mechanical load on the surface to be cleaned is important. This is because in many applications, the object can be re-submitted to the intended use of the object that causes new contamination by cleaning. Thereby, cleaning is carried out in a regular cycle with a sustained material load.

  Patent Document 1 describes an apparatus and a method for removing a film from a base layer. In this case, the dry ice cleaning is assisted by a needle device for applying an additional mechanical shock. By the method proposed in this document, particularly hard or fixed contaminants can be removed appropriately. The disadvantage of this device is that the surface shape and object material are limited. Complex shapes, such as tire shapes or grooves or shapes with deep cuts, do not remove contaminants or remove only more or less vertical surface areas. Furthermore, even when using a synthetic resin needle, it should be considered that soft surfaces such as metal surfaces made of copper or aluminum are damaged.

  In other methods known in the prior art, dry ice cleaning is laser cleaning (patent document 2), additional metering of conventional cleaning media (patent document 3) and metering of solid jetting media (patent document 2). 4). Each of these combinations expands the application of dry ice cleaning for contaminants and objects to be cleaned and at the same time enhances the cleaning effect.

  Another approach for enhancing the contaminant removal effect is pursued in Patent Document 5, for example. By increasing the collision speed of the ejection medium, the mechanical effect of dry ice cleaning is enhanced. However, this approach increases the mechanical load and limits the object surface that can be cleaned. Furthermore, increasing the pressure increases the noise.

  Patent Documents 6, 7, 8, and 9 describe methods and apparatuses that enable automatic cleaning. Most of the above methods serve to clean the mold, especially the inner wall of the tire mold, and reduce noise generation. The common point between these methods and devices is to use a soundproof cover and use a robot device / running device. However, this solution has a series of drawbacks, particularly in order to reduce noise. For example, robotic / running devices are expensive and heavy, must be newly adjusted for each mold, and additionally adapted to different shapes. Since the optical check is impossible during the operation, the portion that has not been cleaned is not known until the end of the operation. Furthermore, it cannot be recognized that the parts of the object to be cleaned are removed and swung by a large amount of gas flow, and the object surface is damaged.

  Patent Document 10 describes a method for ejecting an object with an ejection medium. In this case, the ejection medium is guided to the surface of the object by the gas flow. At least dry ice is used as the jetting medium. The contaminants to be removed described in this document must have a hardness greater than that of dry ice, but must have a lower thermal conductivity than the object to be cleaned. Patent Document 10 further requires that at least a part of the contaminants have a different thermal expansion coefficient from the object surface. This greatly limits the material selection of the object to be decontaminated (cleaned) in combination with the respective contaminant (dirt).

The reason for the limitation is apparent from the action of the method described in Patent Document 10. Dry ice has a temperature of about −78 ° C. and therefore has a large temperature difference (ΔT) with respect to the contaminants to be stripped off at normal working ambient temperatures (approximately room temperature, ie 20 ° C.). Dry ice provides rapid surface cooling when in contact with contaminants. This cooling begins at the contaminant surface. As a result, the desired thermal stress based on the temperature difference, in part, the formation of cracks in the contaminants caused by this thermal stress, the contaminants are caused by the collision of the CO ₂ pellets based on the additional mechanical action. Peel off. Therefore, it is advantageous for the CO ₂ pellets to impact at high speed on the surface from which contaminants are to be removed. Furthermore, as described above, CO ₂ rapidly evaporates due to the collision, and its volume becomes very large (sublimation action), and pressure impact occurs. This pressure shock acts strongly in the crack, and when the adherence of contaminants on the object surface is less than the cohesive force in the contaminants, the pressure impact is very effective at the interface between the object surface and the contaminants. Works. Thus, materials with low condensing power are difficult to remove as contaminants, for example powder paints consisting of spray spray areas that are not optimally sintered together. This is because the material is divided into individual pieces due to thermal brittleness.

  Due to the different coefficients of thermal expansion of the object surface and the contaminant required in Patent Document 10, thermal stress is generated between the contaminant and the object surface when the material is cooled with dry ice. This thermal stress will produce the desired shearing action at the interface. This shearing action facilitates the separation of contaminants from the surface of the object to be cleaned.

  In the case of the cleaning method described in patent document 10, it is important that the contaminants are subjected to the action of dry ice and are cooled much stronger and faster than the object to be cleaned. For this purpose, it is assumed that the object to be cleaned has a large heat capacity and a good thermal conductivity. This is because when this is not the case, the rapid temperature equilibrium between the object surface and the contaminants (on both sides of the interface) will counter the important action of dry ice. This is especially true for long-lasting cleaning in the case of large areas and / or stubborn dirt. In general, the longer the contact between the object to be cleaned and the dry ice, the more difficult it is to clean. This is because thermal stress is reduced based on temperature equilibrium. As a result, in extreme cases, it is no longer possible to remove stubborn and extensive dirt effectively by the above method without repeatedly performing the method (after heating the object in the middle). .

  Furthermore, cleaning complex surface shapes is problematic. In particular, surface depressions, deep corners or undercuts are important. This is because the dirt is rapidly removed from the surrounding area, so that the object surface in the immediate vicinity of the remaining contaminants is rapidly cooled, and the dirt in the deep position is determined based on the good thermal conductivity of the object. This is because the thermal stress is lost.

From Patent Document 10, it is clear that the following conditions are important for the effect of CO ₂ jet cleaning.
-The thermal conductivity of the contaminant must be smaller than the surface to be cleaned.
-The object to be cleaned must have a large heat capacity.
-The heat load capacity of contaminants must be small. Thereby, thermal stress is generated.
- in order to keep the results of the washing is to increase the amount of injection medium used (CO ₂ pellets), it is necessary to increase the collision pressure.
-Contaminants must adhere to the surface to be cleaned with a force less than the cohesive force in them.

These conditions ultimately lead to limited choice of object surfaces and removable contaminant materials. In addition, the above conditions require a high collision speed of the CO ₂ pellets in particular. This will cause a loud noise.

German Patent Invention No. 199469957 Specification German Patent Invention No. 20308788 German patent invention No. 10233304 German Patent Invention No. 10010012 German patent invention No. 10254159 German Patent Invention No. 19712513 German Patent Invention No. 19830397 German Patent Invention No. 1937698 International Publication No. 98/07548 Pamphlet International Publication No. 02/07312 Pamphlet

  Accordingly, it is an object of the present invention to provide a method for removing contaminants on an object that reduces or avoids some or all of the above-mentioned drawbacks known from the prior art. In particular, the object is to be able to reduce the generation of noise when cleaning the surface of an object with dry ice. Furthermore, it should be possible to reduce the mechanical load on the surface. Another object is to increase the variety of material combinations of the object to be cleaned (or its surface) and contaminants.

This object is in accordance with the invention in the next step a) preparing a contaminated object, in which case the object has a functional layer on which at least part of the surface adheres the contaminant,
(I) The contaminant adheres to the functional layer with a force that is weaker than the force that the functional layer adheres to the surface of the object located below,
(Ii) the functional layer has a lower thermal conductivity than the object (particularly the area of the object surface);
(Iii) The functional layer can withstand a temperature difference that occurs upon contact with dry ice in the range from −78 ° C. to room temperature,
b) preparing the dry ice, and c) the pollutant by injecting a spray medium consisting of or containing dry ice onto the contaminated part of the object, which is jetted onto the pollutant using a gas stream. Remove,
It is solved by a contaminant removal method having

  If the functional layer is a layer of plasma polymer containing oxygen, carbon and silicon, the object may be a component for a coating device, but in certain circumstances, the object and the functional layer It is advisable to select the combination as the above combination.

For various applications, when the functional layer used in accordance with the present invention is a plasma polymer layer, it is advantageous that the functional layer does not meet some or all of the following characteristics.
-For the measurement using ESCA, the substance amount ratio O: Si is greater than 1.1 and less than 2.6, and the substance amount ratio C: Si is greater than 0.6 and from 2.2 Is also small,
The plasma polymer layer is a gradient layer that can be produced by changing the polymerization conditions over time;
The plasma polymer coating contains hydrogen and / or fluorine, in which case
1.8: 1> n (H and / or F): n (C) <3.6: 1
Is true.

In particular, the plasma polymer layer that does not satisfy the plurality or all of the above characteristics has a plurality or all of the following characteristics.
-Amount ratio O: Si is greater than 0.75 to 1.1,
-Ratio C of substance amount: Si is 2.2 or more and less than 2.5,
The functional layer of the plasma polymer consists of carbon, silicon, oxygen, hydrogen and possibly ordinary contaminants, calibrated to the C 1s peak aliphatic component at 285.00 eV in the ESCA spectrum of the plasma polymer product In contrast, compared to polydimethylsiloxane (PDMS) whose end group is trimethylsiloxy having a kinematic viscosity of 350 mm ² / s at 25 ° C. and a density of 0.97 g / mL at 25 ° C., the Si 2p peak Having a binding energy value shifted by up to 0.44 eV for higher or lower binding energies, and the O 1s peak shifted by up to 0.50 eV for higher or lower binding energies (In addition, further restrictions on this feature are possible or advantageous, see below).

  The advantageous method according to the invention is carried out by a contaminated object having a functional layer. In the case of this object, one or more of the parameters “object type”, “contaminant type” and “functional layer composition” may be advantageous as described below and / or in an embodiment characterized in detail. Have

  As used herein, a contaminant is understood to be a soil that remains regularly attached to the surface of an object during a given application or use of the respective object. The contaminant may further be a removable layer applied to the object. Contaminants are generally natural products, printing inks, adhesives, rubber, raw rubber, synthetic resins, paints, foods, inorganic materials that can be cured (partially) as raw materials for building materials such as polymer concrete, For example, deposits of chemicals such as oils and / or fats, metal layers such as galvanizing, chemical products, biotechnological products or raw materials for producing chemicals, for example biological materials such as algae It may be a peelable organic and / or inorganic (metal and non-metal) material. The contaminant may be the remainder or precursor of the material.

The functional layer should satisfy the following characteristics:
-Since the functional layer has a low energy anti-adhesion surface on the opposite side of the object surface, the adhesion / adhesion action of contaminants is reduced.
The functional layer has sufficient adhesion to the object surface so that it is not removed together with contaminants;
The functional layer has a sufficiently large internal strength / surface hardness; Thereby, the functional layer is not damaged by the collision of dry ice and the subsequent sublimation of dry ice.
-The functional layer can withstand the temperature differences that occur during contact with dry ice, starting from normal working conditions, i.e. in particular at room temperature (20 ° C). This means that the functional layer can withstand a temperature difference of from about 20 ° C. to at least −78 ° C. without causing low temperature embrittlement. The functional layer does not cause low temperature embrittlement, and a temperature difference of 120K, more preferably a temperature difference of 140K, more preferably a temperature difference of 220K, very preferably a temperature difference of 350K, even more preferably a temperature difference of 428K. It is advantageous to withstand. The functional layer withstands low temperature embrittlement in the range of 250 ° C. to −78 ° C., preferably 350 ° C. to −78 ° C., more preferably in the range of 350 ° C. to −85 ° C. or lower.
The functional layer has a lower thermal conductivity than the object / object surface in order to assist the cleaning action performed by dry ice. The functional layer actually acts adiabatically and can prevent the rapid occurrence of temperature equilibrium between the object and the contaminant.
It is therefore advantageous if the functional layer has a lower thermal conductivity than the contaminants. This aids the cleaning action performed by dry ice. Thermal stress is strongly generated due to the delayed temperature equilibrium between the contaminant and the functional layer. Thereby, an exfoliating action will occur, particularly at the interface between the contaminant and the functional layer. At the same time, the functional coating is a thermal insulation for the object surface. Thus, an object having a small heat capacity and a large thermal conductivity can be treated by the method according to the present invention. Due to the thermal insulation of the functional coating, the high temperature condition of the original object surface is not very important for the contaminant removal result. An important part of the present invention is that when removing contaminants of an object using dry ice, contaminants (contaminants as specified herein are advantageous) and objects (also The use of functional coatings in the advantageous embodiments described below, in particular, to delay the temperature equilibrium between the object and the object as specified.

  All the proposed individual properties of the functional layer contribute to the implementation of the method according to the invention. However, not all properties need to be met to enable this method. In general, the more the proposed properties of the functional layer used, the easier it is to carry out the method according to the invention.

  Due to the proposed properties, the functional layer can improve the thermal action of dry ice cleaning. At the same time, the functional layer reduces the adhesion of contaminants, so that dry ice can be injected at a lower pressure when removing contaminants. Thereby, the mechanical load on the surface is reduced and in particular the noise generated during dry ice cleaning is reduced. At the same time, a low surface temperature of −78 ° C. or lower can be achieved quickly. The functional layer further reduces the risk of damage to the object to be cleaned and broadens the material selection for the object to be cleaned. It is important that the functional layer does not cause weakening or thermal stress at the above temperature and temperature difference. Thus, dry ice carrier gas streams at a speed of 150 m / s or less, preferably 120 m / s or less, can be used in the process according to the invention. Similarly, it is advantageous if dry ice contains little water, thereby reducing the risk of damage by water ice and / or if dry ice is used in the form of snow and / or pellets.

In order to use the method according to the invention, it has been found that an apparatus equipped with an injection device for cleaning contaminated objects with dry ice is very effective. This injection device itself
a) having more aligned paths, each path having a hole at the injection outlet, which makes the propellant flow out at an angle of 30-50 ° with respect to the longitudinal axis of the injection device, and / or Or b) with a device, which ensures that the dry ice passes through a hole with a diameter of 0.3 mm or less before it flows out of the jetting device.

  The device described in b) is for example a sieve or something similar. This device guarantees the desired pellet size and may be a passage device in the form of a perforated plate, for example. This device prevents the passage of large pellets and brings the pellets to the required dimensions.

  Instead of a size limiting device or a pellet injection system, a snow injection system can be used.

  The advantage of the above device for cleaning contaminated objects with dry ice is that, in particular, the same cleaning effect as in the case of a standard injection device with a high-speed gas flow is obtained by generating rotational motion and at the same time optimizing the collision angle. It is to be done. Due to the rotation and impact angle, there are almost no shadows in the uncleaned cut due to the limited movement in removing contaminants in the assembled object, such as a mold. In order to reduce the mechanical load of the functional layer by reducing the sound pressure during cleaning to 100 dB (A) or less, and also reducing the pressure of the carrier gas flow, especially by combining the device with a functional coating. Contribute to. This is because the impact force of the dry ice jet is highly dependent on the jet pressure and is not greatly affected by the size of the particles. Furthermore, the impact force of the dry ice jet flow is not affected by the flow rate, and is likewise not affected by the work interval if it is within appropriate limits.

It is a cross-sectional view of an injection device. It is the schematic for clarifying an injection angle. It is a figure which shows the injection pattern of the apparatus which concerns on this invention. It is a figure which shows the injection pattern of the conventional apparatus for wash | cleaning with dry ice.

FIG. 1 schematically shows the important parts of the apparatus according to the invention for carrying out the method according to the invention.
The operation of the part of the apparatus according to the invention shown in FIGS. 1a to 1d for washing contaminated objects with dry ice is as follows.

  From the pellet inlet 1, the pellets are carried into the injection device under the action of the carrier gas flow. Generally used pellets are in the form of rollers with a diameter of 3 mm and an unspecified length. The pellets are pressed against the die plate 2 having a hole of 0.3 mm or less under the pressure of the carrier gas flow. Thereby, a pellet is shattered. Thereby, dry ice pieces are produced. The dry ice pieces can pass through the die plate and are carried together by the carrier gas stream. A large piece of dry ice bounces back and hits the die plate again under the action of the carrier gas flow. This is repeated until the dry ice pieces are completely crushed so that they can pass through the die plate.

When path split 3 is initiated, the material flow is split into three paths that are separated from one another. At the beginning of the path split 3, as can be seen from the cross-sectional view 8, the paths are not yet completely separated. This can improve material flow. The complete separation of the paths is shown in a schematic cross-sectional view labeled 9. The propellant (crushed pellets) flows out from the jet flow part 4. In this case, the position of the path is shown by a cross-sectional view 10. Outflow occurs at an injection angle of 40-60 °. This will flow out at an angle of 30-50 ° with respect to the longitudinal axis of the injector. The device generates a spray pattern having a centrifugal force action 6. Unlike the known spray pattern 7 according to the prior art, this spray pattern has a lateral movement of the spray medium, so that the spray medium can satisfactorily reach a complicated surface structure such as an undercut. The method according to the invention is very suitable for dirty objects having a functional layer on a part of the surface to which contaminants adhere. in this case,
-The contaminants are weaker than the surface of the object located below the functional layer and adhere to the functional layer.
-The functional layer has a lower thermal conductivity than the object.
-Can withstand temperature differences caused by contact with dry ice at room temperature.
Therefore, such an object is also a component of the present invention. Such an object is preferably not a component of a painting work device.

  For such an object according to the present invention, it is advantageous if the functional layer is based on a fluorine organic material and / or a silicon organic material.

  A plasma polymerized coating is advantageously used as the functional layer. A plasma polymerization coating is a coating generated by gas phase deposition using a plasma source. In this case, a precursor that is fragmented in the gas phase is used for the gas phase precipitation. This fragmentation is carried out in such a way that the substance to be deposited is polymerized (plasma polymerization) in the gas phase and / or on the surface to be deposited.

  During plasma polymerization, gaseous substances containing a minute amount of at least carbon, silicon and / or sulfur are excited and fragmented in the plasma. Excitation and fragmentation of these materials, especially molecules of plasma-polymerizable precursors (often referred to as monomers), in the gas or vapor state can result in electrons and / or energy-rich ions and / or energy-rich photons. This is done by irradiating. In so doing, charged or electrically neutrally excited molecular fragments are produced. These molecular fragments can already react with each other in the gas chamber. Furthermore, the molecular fragments are electrically neutralized and / or reverse excited and / or reflected by impact interaction with the surface. Furthermore, molecular fragments or their reaction products can be deposited on the surface and form a layer there. This layer is often formed by forming a chemical bond.

  Plasma deposition and its ion irradiation and / or electron irradiation and / or photon irradiation continuously act on the deposited layer. Thus, other reactions can be initiated in the deposited layer, such as the formation of free valences while separating atoms or molecular fragments. This free valence can be recombined by bonding reactive species from the gas layer or by cross-linking within the layer with adjacent valences. Thereby, a high degree of crosslinking can be achieved in the coating.

  During plasma polymerization, the height structure, relief and relief of the surface to be coated is usually well maintained. This is often referred to as surface structure mimicry.

The properties of the plasma polymer layer usually depend on the monomers used and the production conditions. The plasma polymer layer is distinctly different from the polymer, for example in terms of its structure, due to the typical properties of the plasma polymer.
-The structure of the plasma polymer is totally in common with the structure of the precursors used, based on fragmentation during plasma excitation.
-The plasma polymer layer does not have a regular structure due to fragmentation during plasma excitation. The plasma polymer is highly cross-linked but can nevertheless have covalent bonds.
The plasma polymer layer usually has long-lived free radicals that are saturated by oxygen and / or moisture in the air only after production and over time.
-The plasma polymer layer does not have tacticity (that is, there is no regularity of repeating repeating units). This is because the repeating unit of the configuration is not generated by the coordination chain reaction.
The plasma polymer layer is amorphous.

  In the present invention, a functional layer of a gradient layer of a plasma polymer that can be produced by changing the polymerization conditions over time is advantageous. The polymerization conditions mean parameters that are particularly important for precipitation during the polymerization. Such a gradient layer is described, for example, in DE 100 00 737, in particular in the claims.

When measuring using ESCA, the substance ratio O: Si is greater than 0.75 and less than 2.6, and the substance ratio C: Si is greater than 0.6 and less than 2.5. (Such layers are described in particular in WO 03/002269 and DE 10131156 A1, in particular in the claims) and / or the functional layer of the plasma polymer It is particularly advantageous for the functional layer to consist of carbon, silicon, oxygen, hydrogen and possibly ordinary soils. In this case, in the ESCA spectrum of the plasma polymer product, kinematic viscosity of 350 mm ² / s at 25 ° C. and 0.97 g / mL at 25 ° C. when calibrated to the C 1s peak aliphatic component at 285.00 eV. Compared to trimethylsiloxy-time-limited polydimethylsiloxane (PDMS) having a density of: the Si 2p peak has a binding energy value shifted by up to 0.44 eV for higher or lower binding energies And the O 1s peak has a binding energy value shifted by up to 0.50 eV for higher or lower binding energies (such a layer in particular in the application of German document No. 102006018476.9 In particular in the claims).

For contaminated objects according to the invention, it is very advantageous if the plasma polymer coating (functional layer) contains hydrogen and / or fluorine. in this case,
1.8: 1 <n (H and / or F): n (C) <3.6: 1
Preferably 2.2: 1 <n (H and / or F): n (C) <3.3: 1
Is true.

  A ratio of 1.5 ≦ n (C): n (O) ≦ 2.5 is particularly advantageous for the functional layer.

  In the present invention, it is advantageous if the functional layer is bonded to the surface of the object via a binder or primer. In this case, the binder may comprise a plasma polymer coating. It is advantageous if the functional layer has a thermal conductivity of 0.5 W / mk or 0.1 W / mk to 1 W / mk. For a given application, it is advantageous if the functional layer is thicker than 1 μm. However, a thickness of 0.01-1 μm is advantageous.

  A plasma polymer coating having a thermal conductivity of 0.05 to 1 W / mk and silicon organic properties and / or fluorine organic properties is particularly suitable.

  Plasma polymer coatings are extremely contour mimicry and can be made very thin, so that the object that is the mold does not need to be made with smaller dimensions than it actually is and can adhere well to the object surface So very suitable. The plasma polymer layer has high hardness and internal strength. This is because the plasma polymer layer is cross-linked in all three directions in a clogged manner. In that case, the silicon organic base and / or fluorine organic base plasma polymer coating can be very well constructed as a gradient layer, so that it adheres well to the surface of the object and can form a low-energy non-stick surface. . Depending on the layer composition and the deposition conditions, the layer can then be optimally adapted in a contamination manner to the method according to the invention, in particular to the object surface to be cleaned. Optimization in this range is easily possible with few attempts for the expert.

  The plasma polymer layer described above, particularly the plasma polymer layer described as being advantageous, maximizes the temperature gradient in a highly advantageous manner, thereby maximizing the thermal effects of dry ice cleaning. At the same time, the adhesion of contaminants is reduced. Thereby, the working pressure of the carrier gas flow for dry ice and thus the flow velocity can be reduced by the above method. As a result, the spray pressure is lowered and the surface temperature is lowered, so that the action of heat can be further enhanced. The reduction in the working pressure or impact force of the dry ice grains further makes it possible to process mechanically sensitive materials. In particular, noise is reduced. Basically, it was possible to work with dry ice of any size, especially pellets with a maximum diameter of 0.3 mm proved to be effective.

  The method according to the invention is very well applicable to objects that must be cleaned regularly. This method is further suitable for removing coatings (on the functional layer) and cleaning contaminants that are deposited in the normal manner.

  Applications are especially adhesive processing, synthetic resin processing, rubber processing, especially tire manufacturing, paint processing, food processing, surface improvement as in the case of electrolytic layer galvanization, printing ink processing, construction material manufacturing, textile industry, chemical industry, The biotechnology and pharmaceutical industry.

  Objects to be removed of contaminants include, for example, molding dies (including embossing dies) or parts thereof, presses or parts thereof, devices or parts for applying adhesive, vulcanizing dies or parts thereof, soldering Jigs, printing presses or casings of printing machines or other parts, eg coating equipment components such as grids, tension frames (dough modification), cutting devices (garbage or other materials deposited by compression), grill grate , Industrial baking molds (waffle baking molds), embedded lamp prisms (airfield marker lamps), chemicals, chemical ingredients, inks, paints, polymers, foods and / or other natural substances mixed, refilled, transported, transported Devices for film formation, measurement, metering, heating, cooling, drying, separation, crushing, storage, curing and / or washing, eg filters, sieves, Exchangers, cutters, chemical, biochemical or biotechnological reactors, extrusion-type components, the remainder of the treated material, especially parts of the above equipment and equipment peripheral equipment contaminated by splashed material .

  Part of the invention is a contaminated object with a functional layer. The object has a thermal conductivity of 20 W / mk or more in the range of the functional layer and / or the functional layer has a thermal conductivity of 10 W / mk or less.

The method according to the invention for the following areas is of particular economic importance.
-Tire manufacturing and rubber processing: When vulcanizing a tire (synthetic rubber, natural rubber) (up to about 180 ° C) in a geometrically detailed mold, the rest of the rubber And the rest of the processing aid grows slowly in the mold. This processing aid is sprayed onto the molding blank (molding blank pretreatment). In this case, the mold must be cleaned in a regular cycle. The same applies to other areas of rubber processing.
-Synthetic resin processing: of high temperature embossing when manufactured and processed (typically in the range of 200-240 ° C) by high temperature embossing dies (for example when forming and using adhesives such as polyester adhesives). Sometimes the applied temperature will cause the adhesive to crack. This grows slowly in the mold. The same effect occurs when processing soft elastic foamed synthetic resins (eg PU or foamed melanin) and technical nonwovens. Therefore, in this case as well, contaminant removal must be performed periodically.
For example, mold release agents are used regularly when processing synthetic resins such as polyurethane, epoxy resins or hot melts. This release agent grows slowly in the mold. This contaminant must also be removed at regular cleaning time intervals.
-Adhesive processing: adhesive (1K, 2K, with or without solvent), hot glue, cold glue, photoresist, paint, solder resist, linoleum, oil, resin, eg roller application tool, When processing and metering in a press, laminating device, casting device or sealing device, a residue often occurs. This remainder should be periodically washed away.
-When processing printing inks / black inks for printing, the tools used should be regularly decontaminated.
-Food sector: for example, coffee processing, chocolate processing, cheese processing, meat processing, sausage processing and fish processing, or for the production of bread confectionery and cereals, stirrers and transporters are contaminated by food components and their function Should be cleaned regularly to maintain

  It should be noted that the contaminant is the precursor or component of the final product or the remainder of the precursor or component.

  When the tire is vulcanized, the remainder of the rubber and the rest of the processing aid remain on the surface of the vulcanization mold of the vulcanization press. This is slowly cracked by high temperature and repeated vulcanization processes. Adhering and fixing contaminants are generated. This contaminant requires periodic cleaning of the mold.

  In particular, mold valves are contaminated. Therefore, the valve does not perform its function for a long time.

  In order to clean the tire mold according to the method according to the invention, the vulcanization mold provided with a valve has a functional layer of plasma polymer. This functional layer was manufactured as follows.

  With this coating, which has a thermal conductivity of less than 1 W / mk and mimics the contour, the mold can be quickly and dry ice dried when a dry ice carrier gas stream with a speed of up to 150 m / s is used. It can be cleaned effectively. As a result, the generation of noise during cleaning was greatly reduced. Furthermore, dry ice consumption could be reduced by about 50%. Furthermore, the above-mentioned functional layer was able to extend the time cleaning interval by 8 to 10 times. The valve is no longer almost closed, so it can be easily cleaned and hardly needs to be replaced. The valve also has a low mechanical load.

1 Pellet inlet 2 Die plate (hole size is 0.3mm or less)
3 Start of path separation (feathered pitch consisting of three parts)
4 Injection outlet 5 Injection angle 6 Injection pattern (centrifugal action according to the present invention)
7 Injection pattern (dots in the prior art)
8 Schematic cross-sectional view of path separation to be started 9 Schematic cross-sectional view of path separation 10 Schematic cross-sectional view of the path position at the injection outlet 11 Schematic diagram of the path in the injection device (broken line)

Claims (13)

A contaminated object having a functional layer on at least a portion of its surface to which contaminants adhere;
(A) The contaminant adheres to the functional layer with a force that is weaker than the force that the functional layer adheres to the surface of the object located below,
(B) the functional layer has a lower thermal conductivity than the object;
(C) The functional layer can withstand a temperature difference that occurs upon contact with dry ice in the range from −78 ° C. to room temperature,
(D) objects rather than the components for the coating operation device,
The functional layer is based on a fluorine organic material and / or a silicon organic material,
(A) For the measurement using ESCA, for the functional layer,
The mass ratio O: Si is greater than 0.75 and less than 2.6, and
The mass ratio C: Si is greater than 0.6 and less than 2.5 and / or (B) the functional layer of the plasma polymer is carbon, silicon, oxygen, hydrogen and possibly normal contamination In the ESCA spectrum of the plasma polymer product, when calibrated to the aliphatic component of the C 1s peak at 285.00 eV, a kinematic viscosity of 350 mm ² / s at 25 ° C. and 0.97 g / 25 at 25 ° C. Bonds with a Si 2p peak shifted by up to 0.44 eV for higher or lower binding energies compared to polydimethylsiloxane (PDMS) with a trimethylsiloxy end group having a density of mL The O 1s peak has a binding energy value that is offset by a maximum of 0.50 eV with respect to the higher or lower binding energy. Have
Contaminated object. The contaminated object of claim 1 , wherein the functional layer is a plasma polymer coating. The contaminated object according to claim 2 , wherein the functional layer is a plasma polymer gradient layer that can be fabricated by changing the polymerization conditions over time. The plasma polymer coating contains hydrogen and / or fluorine,
1.8: 1 <n (H and / or F): n (C) <3.6: 1
Preferably 2.2: 1 <n (H and / or F): n (C) <3.3: 1
The contaminated object according to claim 1 , wherein: Objects are adhesive processing, rubber processing, synthetic resin processing, food processing, surface improvement, printing ink processing, construction material manufacturing, component parts of equipment for fiber manufacturing and processing, lamps, prisms, optical components and chemical industry, Contaminated object according to any one of claims 1 to 4 , selected from the group consisting of components for the pharmaceutical industry and biotechnology. Contaminants are raw materials, biological materials or precursors for producing adhesives, synthetic resins, rubber, paints, food components, metal layers, printing inks, construction materials, chemical products, biotechnological products or drugs. 6. A contaminated object according to any one of claims 1 to 5 , which is selected from the group consisting of a body or its residue. The contaminated object according to any one of claims 1 to 6 , wherein the object has a thermal conductivity of 20 W / mk or more in the range of the functional layer, or the functional layer has a thermal conductivity of 10 W / mk or less. . An apparatus for cleaning a contaminated object with dry ice, the apparatus comprising an injection device, the injection device having a path (11) aligned with (a), each path being an injection outlet (4) With a hole in the nozzle, which causes the propellant to flow out (5) at an angle of 30-50 ° with respect to the longitudinal axis of the injector, or (b) comprises a die (2), An apparatus in which dry ice is guaranteed to pass through a hole with a diameter of 0.3 mm or less before flowing out of the jetting device. A method for removing contaminants, the method comprising the following step a): A contaminated object or object according to any one of claims 1 to 7 is a component of an apparatus for paint processing Preparing an object that differs from the object according to any one of claims 1 to 7 only in respect,
b) preparing the dry ice, and c) the pollutant by injecting a spray medium consisting of or containing dry ice onto the contaminated part of the object, which is jetted onto the pollutant using a gas stream. Removing, including, methods. 10. A method according to claim 9 , wherein the apparatus according to claim 8 is used in step c). 11. A method according to claim 9 or 10 , wherein in step c) a dry ice carrier gas stream with a velocity of 150 m / s or less is used. 12. A process according to any one of claims 9 to 11 , wherein the dry ice is substantially free of water and / or is used in the form of snow or pellets. Contaminants as described in any one of claims 1, 6 , 7 and objects as described in claims 1, 5 , 7 during the removal of contaminants from the object by dry ice Alternatively claim 1, for the object from the object as described retards temperature equilibrium between the only different objects point is a component of a paint processing device 5,7, claim 1-4 Use of a functional coating as described in any one of the above.

Images