JP2005515312A - Composite doctor blade - Google Patents

Abstract

  A doctor blade 10 is provided which is suitable for paper manufacture, in particular for use in calendaring. The doctor blade includes a plurality of composite layers 32 in which most of the fibers are arranged in a direction substantially parallel to the longitudinal direction of the doctor blade.

Description

  The present invention relates to a composite doctor blade. In particular, the present invention relates to a composite doctor blade for use in a paper industry, for example, a calendar device for printing paper. Here, the term “calendar” and similar terms are used here for the production of calendar paper, which is an independent calendar unit in a super calendar, or a paper making device such as a calendar device, a gloss calendar device, and a nip calender device. It means the calendar unit inside.

  Doctor blades are widely used for removing various things attached to a roll surface in a roll member for a papermaking apparatus. Due to the characteristics of the doctor blade, when removing contaminants from the roll surface, the roll surface, the doctor blade itself, or both are worn. Also, the paper component, particularly the coating component, tends to wear, and the roll surface of the roll member of the papermaking apparatus tends to be polished and worn. Conventional doctor blades are composed of, for example, steel, stainless steel, nickel, bronze, or a metal or plastic coated with a metal or ceramic, or a composite material such as a fiber reinforced polymer material. For example, FIG. 1 shows an outline of a typical paper making apparatus in which a doctor blade 2 is arranged on a roll surface 16 of a roll member 12 such as a calendar roll. As shown in FIG. 1, the doctor blade is provided with a blade end portion 14 that is normally inclined at 45 degrees.

  In general, a metal blade has high rigidity and excellent grindability in the direction of the apparatus, that is, in the direction perpendicular to the rotation axis of the papermaking roll member. Here, the direction of the apparatus in the papermaking process usually refers to the traveling direction of the paper web passing through the papermaking apparatus, and refers to the direction indicated by the arrow 18 in FIG. Such a blade is easily corroded and causes the roll member to be extremely worn.

  Plastic blades are used in places unsuitable for metal blades. However, in general, the plastic blade has a drawback that the rigidity is lowered and deteriorates easily under a temperature environment usually exposed in the papermaking process.

  A blade composed of a composite material is generally composed of a plurality of fiber layers impregnated with a resin, and each fiber layer is in a direction perpendicular to the direction of the apparatus, that is, a paper roll member. Each of the fibers extending along the direction parallel to the rotation axis is a woven structure in which the fibers are woven at a certain ratio. Here, the direction perpendicular to the machine refers to the direction indicated by the arrow 20 in FIG. 2 as the direction perpendicular to the traveling direction of the paper web, that is, the direction parallel to the rotation axis of the papermaking roll member. Blades made of composite material wear faster than metal blades, but have less wear on the roll surface than metal blades. Short blade life is considered a drawback of composite blades, and improved wear resistance is desired for many doctor applications. In conventional calendering, wear of composite doctor blades is usually allowed because extreme wear of the roll member has a detrimental effect on the final properties of the paper.

  Composite doctor blades are often used for on-line calendars where the nip pressure and roll temperature are relatively high. Under such operating conditions, many additives and contaminants are likely to adhere to the calendar roll surface. For this reason, when the roll member is not repaired continuously, additives and contaminants accumulate beyond the allowable value, which directly affects the final paper characteristics such as gloss and slip. Furthermore, the roll surface deteriorates due to wear by debris and contaminants, and eventually becomes unrepairable. Such deterioration of the roll surface causes a reduction in roll performance due to an uneven surface that causes unevenness over the entire width of the paper web during calendar processing. Therefore, in order to keep the paper quality constant under high productivity and high efficiency, almost continuous repairs for removing contaminants on the calendar roll member are performed during operation. As a result, improvements in wear resistance and lifetime of composite doctor blades have been made by various methods.

  In order to improve the wear resistance of the calendar roll member, various efforts are made with respect to the operating conditions in the calendar process. As such a method, a method of forming a thin thermal spray coating layer on the roll surface is being frequently used in order to prevent deterioration of the roll surface leading to a decrease in roll performance. Thermal spray here is usually heated in powder form by one of three standard processes such as plasma, high-speed oxygen-combustant gas mixture (HVOF), or spray gun, It means welding on the roll surface. Such thermal spray coating is performed using ceramic or metal as a base material. The roll surface coated by thermal spraying has a very small surface roughness, and obtains high characteristics necessary for a roll member used for producing glossy coated paper.

  The above-mentioned thermal spray coating prevents the roll surface from being scratched during the repair work that is intermittently performed such as peeling the paper wound on the roll when the paper web breaks. However, in general, in the case of a spray-coated roll member, the roll surface is deteriorated during repairs that are performed almost continuously. The roll surface coated by thermal spraying becomes rough because its surface is deformed by the action of a doctor blade and contaminants after a long period of use. When the roll shape and roll surface roughness are deteriorated to such an extent that the paper quality is adversely affected, the roll member is removed for grinding the roll surface. Such a grinding process has a significant impact on productivity reduction and associated cost increase. In addition, this grinding process removes various thermal spray coating layers from the roll surface. Such a thermal spray coating layer occupies a large proportion of the manufacturing cost and equipment of the roll member, and it is strongly desired to reduce the cost of the thermal spray coating.

  Improving the wear resistance of the composite doctor blade will accelerate the deterioration of the roll surface. On the other hand, a predetermined level of wear resistance is required to minimize the interruption of the manufacturing process associated with the replacement of the doctor blade. A doctor that can effectively remove contaminants almost always from the spray-coated roll surface, has practically sufficient wear resistance, and can keep the roll surface roughness at a low level while minimizing the degradation of the spray coating. A blade is required.

  In the present invention, since the doctor blade is provided with a large number of unidirectional fibers having an abrasive property arranged in a direction parallel to the longitudinal direction of the doctor blade, contamination from the roll surface is minimized while minimizing deterioration of the roll surface. Can be removed. Further, the roll surface can be continuously contacted without serious damage to the roll surface.

  Moreover, according to the doctor blade which concerns on this invention, it can be used conveniently for a papermaking apparatus, especially a calendar apparatus. Moreover, according to the doctor blade which concerns on this invention, the abrasiveness for making it the clean roll surface without the deterioration required for manufacture of paper can be provided. Furthermore, the doctor blade according to the present invention can make the rigidity in both the longitudinal direction and the vertical direction thereof necessary for proper repair. Further, the doctor blade according to the present invention can make the progress of wear slower and more uniform than before. In addition, the doctor blade according to the present invention can maintain the surface roughness of the roll surface at the design level.

  The present invention has one aspect characterized in that the doctor blade includes a composite material having a plurality of unidirectional fibers impregnated with a resin, and further includes the following more preferable characteristics.

In other words, the doctor blade according to the present invention is characterized in that it includes a laminate of a plurality of layers of the composite material. The doctor blade according to the present invention is characterized in that the unidirectional fibers are selected from the group consisting of glass fibers, ceramics, and mixtures thereof. The unidirectional fibers are preferably made of long continuous fibers or twisted yarns thereof. This fiber is more preferably a glass fiber. Further, the unidirectional fiber is supplied from a unidirectional fabric. The unidirectional fabric has at least 60% or more of the total weight of the unidirectional fibers, preferably at least 75%, more preferably at least 90%. The remaining fibers are second fibers here, but are preferably aligned in a direction other than the direction parallel to the longitudinal direction. The outer diameter of the one-way fiber is equal to or greater than the outer diameter of the second fiber. The outer diameter of the unidirectional fiber is preferably about 450 to 1500 μm, and the outer diameter of the second fiber is preferably about 400 to 700 μm. The doctor blade according to the present invention is characterized in that the unidirectional fabric further comprises non-abrasive fibers selected from the group consisting of carbon, rayon, aramid, polyester, and mixtures thereof. The non-abrasive fibers preferably include carbon fibers oriented in a direction substantially perpendicular to the longitudinal direction. The unidirectional fabric may have a weight per unit area in a range of about 230 to 610 g / m ² . The resin includes a thermoplastic resin or an epoxy resin, that is, an epoxide, an oxylene, or an exoxylene. The glass transition temperature (hereinafter referred to as Tg) of this resin is preferably about 65 to 315 ° C, and more preferably about 85 to 315 ° C. The resin is selected from the group consisting of glass spheres, glass fibers, glass fragments, synthetic or industrial diamond pieces, silica pieces, silicon carbide pieces, boron pieces, zirconium pieces, aluminum oxide pieces, and mixtures thereof. The polishing additive is further provided.

  According to another aspect of the present invention, a doctor blade having a plurality of unidirectional fibers for polishing impregnated with a resin is disposed so that a longitudinal direction thereof is substantially parallel to a rotation axis of the roll member. Provided is a method for cleaning a roll surface of a roll member that rotates about a rotation axis, comprising a first step of bringing the member close to a roll surface of the member and a second step of pressing a blade end of the doctor blade against the roll surface. It is.

  Moreover, the finish of a roll surface can also be performed by the method mentioned above.

  The present invention further has the following more preferable features. That is, the above-described method according to the present invention is characterized in that the blade end portion of the doctor blade is kept in contact with the roll surface almost continuously during operation of the roll member. Further, the first step is characterized in that the doctor blade is disposed at an operation angle inclined by approximately 25 to 30 degrees. Further, the pressure of the doctor blade in the second step is approximately 85 to 700 N / m, preferably approximately 175 to 440 N / m. When finishing the roll surface, the surface roughness of the roll surface is maintained at approximately 0.025 to 0.20 μmRa, preferably 0.025 to 0.20 μm, during the useful life of the doctor blade. It is characterized by that.

  Another aspect of the present invention is to provide a method for producing a doctor blade, comprising a step of impregnating a composite material containing unidirectional fibers with a resin. Further, the present invention further has more preferable features shown below. That is, the method further includes a step of stacking a plurality of the composite material layers impregnated with the resin to form a laminated structure. The method further comprises a step of curing the resin impregnated in the composite material by increasing the temperature and pressure. The cured composite material further includes a step of cutting the plurality of doctor blades into a plurality of doctor blades each having a longitudinal axis.

  Other features and effects of the present invention are shown in the following detailed description and drawings.

  The composite doctor blade 2 shown in FIG. 1 is capable of removing contaminants from the roll surface 16 of the papermaking roll member 12 whose blade end portion 14 rotates about the axis indicated by the arrow 22 with respect to the roll member 12. It is arranged. The direction of the apparatus is indicated by an arrow 18, and the direction intersecting this is indicated by an arrow 20. Hereinafter, a doctor blade is demonstrated as what is used by the state and method shown in FIG.

  As shown in FIGS. 2 and 3, the doctor blade 10 according to the present invention includes a laminate composed of a plurality of composite layers 32 each having a large number of unidirectional fibers 31 and a plurality of fibrous reinforcing layers 30. I have. The composite layer 32 includes a layer in which unidirectional fibers 31 arranged in a direction substantially parallel to the longitudinal direction of the doctor blade 10 are laminated. Unlike the composite layer 32, the reinforcing layer 30 is arranged such that most of the fibers constituting the reinforcing layer 30 are not parallel to the longitudinal direction of the doctor blade 10. The reinforcing layer 30 includes a laminated body for reinforcing the doctor blade such as rigidity and strength and providing an appropriate thickness. 2 and 3 show an outline of the reinforcing layer 30 in which the fiber direction is omitted. The reinforcing layer 30 may be a woven fabric or a non-woven fabric, and the fiber direction is the device direction. Alternatively, two directions or more directions may be used.

  In the embodiment of the doctor blade 10 according to the present invention shown in FIG. 2 and FIG. 3, respectively, it has a laminated structure of 9 layers. In general, the doctor blade has 5 to 20 layers, but depending on the thickness required for the doctor blade 10, there may be more layers. The number of layers suitable for such a composite doctor blade is determined based on individual repair requirements as is well known to those skilled in the art. Each of the composite layer 32 and the reinforcing layer 30 is impregnated with an epoxy resin or a thermoplastic resin so that these layers are laminated, and is fixed under pressure and temperature to form a single laminated structure. .

  The doctor blade 10 in the embodiment shown in FIG. 2 is formed by alternately laminating reinforcing layers 30 and composite layers 32. The reinforcing layer 30 is preferably provided with glass fibers having a woven structure in two or more directions. The doctor blade 10 according to the embodiment shown in FIG. 2 is relatively high for calendering a coated paper web with a relatively high water content, for example approximately 4 to 10%, which causes increased pigment adhesion to the roll surface. Suitable for cases where abrasiveness is required.

  In the doctor blade 10 in the embodiment shown in FIG. 3, the composite layer 32 is laminated at the center, and the reinforcing layer 32 is laminated on the outside thereof. The reinforcing layer 30 preferably includes carbon fibers. In the embodiment shown in FIG. 3, for example, a doctor blade having a low abrasiveness requirement for a calendar unit using a paper web having a moisture content of approximately 1 to 4% and a relatively dry and less contaminated roll surface. Are suitable.

  The laminated structure of the doctor blade 10 in the laminated body is such that the reinforcing layer 30 in FIG. 2 and the central layer 34, which is the composite layer 32 in FIG. If the center layer 34 is not symmetrical, there is a risk of bending or twisting with respect to the longitudinal direction of the doctor blade.

  As the fibers of the composite layer 32, glass fibers, ceramic fibers, and fibers obtained by mixing them are suitable, but glass fibers are preferable. Here, the term fiber includes a single filament (filament) having a length larger than the width or a strand composed of a plurality of filaments. The composite layer comprises relatively short fiber segments or continuous fibers long in the longitudinal direction of the doctor blade. It is preferable that the composite layer mainly includes long continuous fibers.

  Suitable fibers for the composite layer include cast iron, chilled cast iron, cast steel that form the roll surface of the papermaking roll member, or those that have sufficient abrasiveness to thermal spray coatings containing ceramic or metal base materials. Thus, the roll surface can be cleaned and / or polished. Further, as the fiber of the composite layer, a fiber having sufficient hardness to give strength in the longitudinal direction of the doctor blade is suitable. Therefore, if the fibers that make up the composite layer are not hard enough, it becomes a highly flexible doctor blade, and the doctor blade tends to bend when pressure is applied to clean the roll surface. The roll surface repair effect cannot be obtained.

  Unidirectional fibers are usually provided in the form of a fabric. A woven fabric having unidirectional fibers is regarded as a “unidirectional woven fabric” in the art even if a predetermined percentage of fibers are woven in a different direction from the other fibers. In the present embodiment, other fibers including unidirectional fibers arranged in a direction different from the main fibers arranged in the longitudinal direction of the doctor blade will be referred to as “second fibers”. The second fiber is used as a basic structure for preventing the unidirectional fibers from being separated when impregnated with resin or laminated. Such a second fiber is mainly abrasive to the material constituting the roll surface of the papermaking roll member. Suitable unidirectional fabrics comprise 60% of the weight by unidirectional fibers, but are preferably at least 75%, more preferably 90% or more.

  The unidirectional woven fabric preferably has a woven structure, and can retain its shape when impregnating with resin or manufacturing a doctor blade. During manufacture of the doctor blade, a large unidirectional fabric sheet and preferably a reinforcing layer is impregnated with resin. After impregnation, these impregnated layers are laminated together. High temperature and high pressure are applied to the laminate to cure the resin, and the layers are bonded. Then, the cured laminate is cut into one or a plurality of doctor blades each having a longitudinal direction.

  Unidirectional fabrics further comprise non-abrasive fibers such as carbon, rayon, cotton, aramid or aromatic polyamide, polyester, and mixtures thereof, to a lesser extent. Such non-abrasive fibers are used to provide other aspects such as reduced wear or structural strength. The directions of the non-abrasive fibers are all aligned in the direction of the device, the direction intersecting the device, or a plurality of directions. The direction of the non-abrasive fiber is an important factor because it gives the doctor blade strength. For example, in an embodiment according to the present invention, a carbon fiber fabric is used for the unidirectional fabric in order to reduce wear of the doctor blade and add strength. When strength is required in the longitudinal direction of the blade, the orientation of the carbon fibers is arranged substantially parallel to the longitudinal direction. When strength is required in the width direction of the doctor blade, carbon fibers are arranged in a direction substantially orthogonal to the longitudinal direction. Here, when the non-wearable fiber has a glass transition temperature Tg, the temperature should be higher than the surface temperature of the roll member in which the doctor blade is used. If the Tg of the fiber is the same as or lower than the temperature of the roll surface, the melted fiber becomes a contaminant on the roll surface. Here, a person skilled in the art can select the most suitable non-abrasive fiber in order to reduce wear and / or increase the strength according to the individual repair situation.

  When using a conventional doctor blade, the pigments and contaminants removed from the roll surface block the gaps and cracks between the fibers on the blade surface that contacts the work surface of the doctor blade, that is, the roll surface. As a result, the effect of the blade is reduced. On the other hand, in the doctor blade 10 according to the present invention, the direction of the unidirectional fibers is the direction intersecting the direction of the apparatus, so there are almost no gaps and cracks as described above, and clogging of pigments and contaminants occurs. Few. Further, since the unidirectional fibers are arranged in parallel with the roll surface and intersecting the direction of the apparatus, the composite layer 32 shown in FIGS. 2 and 3 also exposes the surface of more fibers to the roll surface. During operation, the unidirectional fibers on the working surface of the doctor blade are broken apart with adjacent unidirectional fibers appearing on the surface one after the other. This disassembly regenerates the working surface of the blade end 14 of the doctor blade shown in FIG. Unidirectional fibers are usually very small pieces that are removed from the roll surface along with contaminants during repair.

  In the conventional doctor blade, the end portion of the abrasive fiber easily affects the roll surface and easily forms a scratch on the roll surface. Since the direction of the main fiber in the general doctor blade is the direction of the apparatus, the roll surface is repaired at the end portion rather than the side surface of the fiber. Under conditions where repairs are almost always made, the roll surface becomes more and more rough in the state described above due to the end of the fiber, and eventually the roll surface and paper quality are unacceptably deteriorated. End up.

  The doctor blade according to the present invention is provided with second fibers or non-abrasive fibers along the direction of the apparatus, but since these fibers are very few, scratches are hardly formed. In addition, it is possible to suppress the end of the fiber from acting on the roll surface. The composite layer of the doctor blade according to the present invention can finish the roll surface as shown in FIGS. 4A and 4B. Here, FIG. 4A is a cross-section of the roll surface 16 of the roll member 12 in FIG. 1 before using the doctor blade 10 of the present embodiment, and the ends of the fibers arranged in the direction of contaminants and / or equipment. It is an enlarged view which shows the surface shape made uneven by the part. FIG. 4B shows the cross-sectional shape at the same position of the roll surface 16 after using the doctor blade 10 of the present embodiment. The doctor blade 10 can unify the convex portions 40 to a certain height L with respect to the roll surface 16 and reduce the surface roughness. The doctor blade 10 according to the present embodiment can finish the surface roughness of the roll surface to about 0.050 to 0.13 μmRa, preferably about 0.050 to 0.13 μmRa. Further, the doctor blade 10 according to the present embodiment has a roll surface roughness of approximately 0.025 to 0.20 μmRa, preferably approximately 0.050 to 0.13 μmRa over the useful life of the blade. Can be maintained. The level of surface roughness achievable by the use of the doctor blade according to the invention depends on the material forming the surface of the papermaking roll member and the individual repair conditions.

  The larger the surface area of the unidirectional fiber that appears on the surface of the composite layer, the more uniform the polished surface is supplied when the roll surface is repaired. And by having a uniform polished surface, the shape of the roll surface can be made more uniform. Also, the larger the abrasive, i.e., the area of the long axis unidirectional fibers that are exposed to the table during repair, the slower and more uniform the doctor blade wear.

The unidirectional woven fabric is preferably a plain woven fabric structure having a relatively low basis weight in which unidirectional fibers and second fibers are woven to cross each other. Here, the unidirectional fabric may be knitted with different openings. This basis weight is indicated by the weight per unit area of the unidirectional fabric. The weight per unit area of the unidirectional fabric is preferably about 230 to 610 g / m ² . Such loose and light weaves have less wear and tend to disintegrate faster under the same conditions compared to firm and heavy knitted ones. However, heavy unidirectional fabrics that are clogged are suitable for repairs that require more abrasiveness to avoid significant wear on the blades and faster disassembly that shortens blade life.

  Loose and light unidirectional fabrics are suitable for repairs that require less abrasiveness, such as paper webs that do not require low moisture content coatings that are less contaminated on the roll surface. On the other hand, clogged and heavy unidirectional woven fabrics are suitable for repairs requiring high abrasiveness and high abrasion resistance, such as coated paper webs with high moisture content that have many contaminants on the roll surface. In addition, as the degree of clogging or weight of the eyes increases, the proportion of the end of the second unit area fiber that contacts the roll surface increases. And as the second fibers are woven, more abrasive material appears on the surface, tangling occurs in the unidirectional fabric, and the higher the degree of clogging and weight, the higher the abrasiveness per unit area. Will show. A person skilled in the art can decide whether to loosen or tighten the weave according to such a policy.

  The outer diameter of the unidirectional fiber is larger than the outer diameter of the second fiber. The outer diameter of the unidirectional fiber is equal to or preferably larger than the outer diameter of the second fiber. Preferably, the outer diameter of the unidirectional fiber is about 450 to 1500 μm, and the outer diameter of the second fiber is about 400 to 700 μm. Here, when the second fiber has an outer diameter larger than that of the unidirectional fiber, it is easy to form a scratch on the roll surface, and the width of the scratch tends to be large.

Unidirectional fabrics with numerous unidirectional fibers include 1093 E-Glass Fabric from Fiber Glast Developments Corporation in Brookville, Ohio, and E-LPb425 from Brunswick Technologies Inc. in Brunswick, Maine. E-LPb567 0 ^o UniDirectional fabric is suitable.

  Resins suitable for impregnation are thermoplastic or epoxy resins. And it is preferable to use the epoxy resin system which has an epoxy resin and a hardening | curing agent for formation of the laminated body of the doctor blade which concerns on this invention. As the resin used for the doctor blade according to the present invention, a resin that can withstand the temperature under individual repair conditions is selected. During operation, the resin used for the doctor blade contacts the roll surface. The resin used should not melt or contaminate the roll surface, but must abrade the unidirectional fibers that appear on the surface. Since the resin is not abrasive, it is preferred that the resin wear away faster than the unidirectional fibers.

  The glass transition temperature (Tg) of the resin is shown as an operating temperature that can be withstood by design. The resin suitable for the doctor blade according to the present invention is preferably in the range of approximately 55 to 315 ° C. depending on the temperature of the roll surface to be repaired. An epoxy resin having a temperature range of about 65 to 315 ° C., more preferably about 85 to 315 ° C. is preferable under a high temperature such as calendering. This is because if the Tg for curing the resin is too low under the respective repair conditions, the resin melts and becomes a contaminant on the roll surface. For doctor blades for rolls performed at relatively low operating temperatures, high Tg resins are not required.

  The epoxy resin systems mentioned above include the System 2000 Epoxy Resin used with Fiber Glast Developments Corporation 2020, 2060 or 2120 Epoxy Hardeners, and EPICURE Curing Agent 9552 from Resolution Performance Products in Houston, Texas. EPON Resin 828 used or EPON Resin 826 used with EPI-CURE Curing Agent W are suitable. EPON Resin 828 or EPON Resin 826 from Resolution Performance Products is cured with other curing agents such as ETHACURE 100 Curative from Albemarle Corporation, Baton Rouge, Louisiana, or Methylene dianiline. A person skilled in the art can select a suitable resin exhibiting the optimum Tg according to the individual repair conditions and, for example, ease of use such as curing time and safety prevention.

  In the doctor blade according to the present invention, the fiber material accounts for about 50 to 70%, preferably about 60 to 70% of the total weight, and the resin accounts for about 25 to 50%, preferably about 30 to 40%. Since the fiber material has a glass transition temperature higher than that of the resin, the Tg of the doctor blade becomes higher as the weight percentage of the fiber of the doctor blade increases. The doctor blade according to the present invention has a Tg of about 75 to 315 ° C. depending on the temperature of the roll surface to be repaired. In the case of calendering at a high temperature, the Tg of the blade is preferably about 100 to 315 ° C, and more preferably about 150 to 315 ° C. As the percentage of fiber increases, the abrasiveness of the doctor blade also increases.

  In general, the thickness of each layer before the laminated structure is about 0.20 to 0.50 mm for the composite layer and about 0.09 to 0.50 mm for the second layer. The thickness of the doctor blade 10 is set to a range of about 1.50 to 3.20 mm, although it depends on an arrangement place in the papermaking process and an exposed environment. The thinner the doctor blade, the more effectively the roll surface can be cleaned while the blade is provided. This is because the blade edge portion of the thin blade is thinner than the blade edge portion of the thick blade, so that a higher pressing force can be applied per unit area than the blade edge portion of the thick blade. On the other hand, the thicker the doctor blade, the greater the material strength and the longer the blade life. Although the width | variety of a doctor blade is also decided by the arrangement | positioning place and exposure environment in a paper manufacturing process, it is about 50-100 mm. A person skilled in the art can select the optimum thickness and width of the doctor blade from the balance between the life of the doctor blade and the degree of contamination of the roll surface.

  Resin used for the composite fiber layer is glass spherules, glass fibers, glass fragments, synthetic or industrial diamond pieces, silica pieces, silicon carbide pieces, boron pieces, zirconium pieces, aluminum oxide pieces, or a mixture thereof. A polishing additive is provided. The impregnating resin also includes friction reducing additives such as carbon pieces and polytetrafluoroethylene powder. Reducing friction between the doctor blade and the roll surface suppresses heat generation during repair and improves the life of the doctor blade. A person skilled in the art can select an optimum additive according to individual repair conditions such as increase / decrease in abrasiveness, reduction of friction, and final desired quality of the product.

The reinforcing layer generally comprises carbon fibers, aramid fibers, ceramic fibers, glass fibers, and mixtures thereof, preferably glass fibers. The reinforcing layer has a woven or non-woven structure, and the fiber direction is mainly the device direction, or two or more directions. The woven structure has higher abrasiveness than the non-woven structure. The reinforcing layer has a plain weave, satin weave, or oblique weave, preferably a plain weave or satin weave structure. The weight per unit area of the reinforcing layer is preferably about 60 to 350 g / m ² .

  Reinforcing layers with carbon fibers are typically used to increase the strength by reducing the friction of the doctor blade relative to the direction of the device. Carbon fiber has high tensile strength and high rigidity, but is not abrasive. Therefore, even if the end portion of the carbon fiber acts on the roll surface, the roll surface is hardly damaged. Aramid fibers also improve the doctor blade's tensile strength and wear resistance. Also, the ceramic or glass fiber reinforcing layer provides the doctor blade with abrasiveness. A person skilled in the art can determine the configuration and the number of layers of the reinforcing layer in the laminated body in accordance with individual repair requirements such as reduction of frictional force, improvement of rigidity, improvement of abrasiveness in consideration of the above-mentioned characteristics. it can.

  Suitable materials for the reinforcing layer include Fiber Glast Developments Corporation's 241 Woven Fiberglass Fabric, 530 3K Graphite Fabric, and 549 5HS Kevlar Fabric, and Brunswick Technology Inc., CBX 300 6k Carbon and ARBX 350 Aramid fabric. preferable.

  FIG. 5 shows a typical multi-stage calendar apparatus including two calendar units 50 each having two soft rolls 52 and one metal roll 54. The soft roll 52 is usually made of an elastic material such as a reinforcing fiber made of an epoxy resin. The metal roll 54 is made of cast iron, chilled cast iron, ductile cast iron, forged steel, or cast steel. Further, the metal roll 54 is subjected to thermal spray coating including ceramic or a metal base material containing carbide, for example. The thickness of the thermal spray coating is usually about 75 to 305 μm. In general, the thermal spray coating can be applied to a base having a surface roughness of 0.20 μmRa or less. The direction of rotation of each metal roll 54 is indicated by an arrow 22. The paper web 60 passes through the calendar unit 50 with the help of a guide roll 62.

  Of the two doctor blades, the first doctor blade 56 is arranged with respect to the metal roll 54 of the first unit 50, and the second doctor blade 58 is arranged with respect to the metal roll 54 of the second unit 50. It is arranged. As shown in FIG. 5, the doctor blades 56 and 58 are arranged at arbitrary positions on the circumference of the metal roll 54 so that the blade end portion 14 shown in FIG. 1 acts in the rotation direction of the metal roll. The Each blade is preferably disposed at a position after the paper web 60 has passed through the nip formed in each unit 50 by the soft roll 52 and the metal roll 54. Such a position allows the doctor blade to more reliably clean the metal roll after the paper web has passed through it. A person skilled in the art can determine the optimum position of the doctor blade in accordance with the individual operating conditions determined by the direction in which the paper web passes and the equipment in the vicinity of the roll to be repaired, as well as safety and maintainability.

  The blade end 14 shown in FIG. 1 is usually formed with an inclination angle of 45 degrees with respect to the reference plane of the doctor blade. The operating angle A of the doctor blades 56 and 58 is usually within a range of approximately 25 to 30 degrees with respect to the tangent line of the roll surface at the position where the blade edge portion of the doctor blade is disposed. The pressing force of the doctor blade against the roll member is mainly about 85 to 700 N / m, preferably about 175 to 440 N / m.

  The doctor blades 56 and 58 are in intermittent contact with the surface of the metal roll 54 as in cleaning. More preferably, during operation of the roll member, it is preferable that the roll member is in contact with the roll surface of the metal roll 54 substantially continuously. By using the doctor blade almost continuously, the polished contaminants can be reliably removed continuously from the roll surface. Therefore, deterioration of the roll surface can be significantly suppressed. Moreover, by using it substantially continuously in this way, the surface roughness of a roll surface can be reduced and a uniform roll surface can be maintained. By suppressing the deterioration of the roll surface and reducing the surface roughness of the roll surface to obtain a uniform roll surface, it is possible to improve the productivity more effectively and manufacture a product with a constant quality. In addition, by maintaining the surface roughness at a desired level while minimizing the deterioration of the roll surface, the life of the roll member is improved, and in the case of a roll member on which thermal spray coating is applied, the life of the surface coating is improved. be able to.

  In the first calendar unit 50, since the paper web is in a state of high moisture content immediately after being coated with the pigment and dried, a doctor blade having a higher abrasiveness as in the embodiment shown in FIG. 56 is usually arranged. In the case of paper or coated paper having a high water content, there is a high possibility that the paper web will adhere to the metal roll 54, and a thin layer of pigment will be formed on the roll surface. Such a coating layer reduces the thermal conductivity from the roll surface to the paper and reduces the gloss level of the paper web. When a blade having low abradability is used in the first unit, it is necessary to increase the pressing force of the doctor blade against the roll surface in order to make it easier to scrape the residue on the roll surface.

  The doctor blade 58 having a low abrasiveness as in the embodiment shown in FIG. 3 is mainly disposed in the second unit 50 in which the paper web is further dried and the adhesion to the metal roll 54 is low. Since the roll member is in a relatively clean state against contaminants, the pressing force of the highly abrasive blade against the roll member is carefully controlled so as not to cause excessive wear on the roll member. When a doctor blade with higher abrasiveness is used for the roll member, the roll surface is severely peeled and the life of the roll surface is reduced. As described above, the abrasiveness of the doctor blade depends on the usage and configuration of the reinforcing layer, the abrasive, the ratio of the impregnating resin in the fiber material, and the degree of opening of the composite material.

  A composite doctor blade was made from 4 reinforcing layers and 3 composite layers. As shown in FIG. 2 in which the outermost layer and the central layer are the reinforcing layers, the laminated structure was formed by alternately stacking the reinforcing layers and the composite layers. The reinforcing layer was formed from a glass fiber fabric of a plain weave type manufactured by Essco Inc. The unidirectional fabric used for the composite layer was Fiber Glast Developments Corporation's 1093 E-Glass Fabric, which is a glass fiber fabric in which the weight of unidirectional fibers accounts for 95% of the total. As the resin for impregnation, an epoxy resin manufactured by Essco Inc. having a Tg of about 90 to 150 ° C. was used. This doctor blade was used in a second calendar unit similar to the second unit 50 shown in FIG. The pressing force of the doctor blade against the metal roll on which the thermal spray coating was applied was about 350 N / m, and the angle was about 27 degrees. The surface roughness of the roll surface after the doctor blade was brought into contact with the roll surface almost continuously for about 21 days was about 0.05 to 0.08 μmRa. After a further 27 days of use, the surface roughness of the roll surface was approximately 0.08 to 0.13 μmRa. Surface roughness was measured using a Surtronic 3+ manufactured by Taylor Hobson Inc., Rolling Meadow, Illinois. As the surface of the roll surface of the roll member becomes smooth, the level of surface roughness becomes a very low value to minimize roll surface degradation. The surface roughness of the roll surface obtained by the doctor blade is convenient for the production of glossy coated paper. The life of each doctor blade that can tolerate wear resistance in an almost continuous use environment was about 5 to 7 days.

  Other embodiments are also included in the scope of the claims. For example, the doctor blade according to the present invention is suitable for use in webs in other industrial fields that use roll members such as printed materials, chemical films, flooring materials, and fabrics. The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is a perspective view which shows the state which made the doctor blade which concerns on the 1st and 2nd embodiment of this invention contact the paper roll member. It is a perspective view which shows the state which decomposed | disassembled the doctor blade which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the state which decomposed | disassembled the doctor blade which concerns on the 2nd Embodiment of this invention. It is an expanded sectional view which shows the surface of the roll member for paper manufacture before using the doctor blade which concerns on the 1st and 2nd embodiment of this invention. It is an expanded sectional view which shows the surface of the roll member for paper manufacture after using the doctor blade which concerns on the 1st and 2nd embodiment of this invention. It is the schematic which shows the calendar unit provided with the doctor blade which concerns on the 1st and 2nd embodiment of this invention.

Explanation of symbols

2, 10 Doctor blade 31 Unidirectional fiber

Claims (40)

A long-axis doctor blade used for a roll surface of a roll member rotating around a rotation axis,
A doctor blade comprising a composite material having a plurality of polishing unidirectional fibers impregnated with a resin.   The doctor blade according to claim 1, comprising a laminate of a plurality of layers of the composite material.   The doctor blade according to claim 1, wherein the unidirectional fibers are selected from the group consisting of glass fibers, ceramics, and mixtures thereof.   The doctor blade according to claim 3, wherein the unidirectional fibers include glass fibers.   The doctor blade according to claim 1, wherein the unidirectional fibers are mainly composed of long continuous fibers.   The doctor blade according to claim 1, wherein the unidirectional fibers are supplied from a unidirectional fabric in which the unidirectional fibers occupy at least 60% or more of the total weight.   The doctor blade according to claim 6, wherein at least 75% of the weight of the unidirectional fabric is unidirectional fibers.   The doctor blade according to claim 6, wherein at least 90% of the weight of the unidirectional fabric is unidirectional fibers.   The doctor blade according to claim 6, wherein the unidirectional fabric includes a second fiber.   The doctor blade according to claim 9, wherein the outer diameter of the one-way fiber is equal to or larger than the outer diameter of the second fiber. The outer diameter of the unidirectional fiber is about 450 μm to 1500 μm,
11. The doctor blade according to claim 10, wherein an outer diameter of the second fiber is approximately 400 μm to 700 μm.   The doctor blade according to claim 6, wherein the unidirectional fabric further comprises non-abrasive fibers.   The doctor blade according to claim 12, wherein the non-abrasive fiber is selected from the group consisting of carbon, rayon, aramid, polyester, and a mixture thereof.   The doctor blade according to claim 13, wherein the non-abrasive fiber includes carbon fibers oriented in a direction substantially perpendicular to the longitudinal direction. The doctor blade according to claim 6, wherein the weight per unit area of the unidirectional fabric, characterized in that it is in a range of approximately 230 to 610 g / m ^2.   The doctor blade according to claim 1, wherein the resin is a thermoplastic resin.   The doctor blade according to claim 1, wherein the resin is an epoxy resin.   The doctor blade according to claim 1, wherein the resin has a glass transition temperature of about 65 to 315 ° C.   The doctor blade according to claim 18, wherein the resin has a glass transition temperature of about 85 to 315 ° C.   The resin is selected from the group consisting of glass spheres, glass fibers, glass fragments, synthetic or industrial diamond pieces, silica pieces, silicon carbide pieces, boron pieces, zirconium pieces, aluminum oxide pieces, and mixtures thereof. The doctor blade according to claim 1, further comprising a polishing additive. First, a doctor blade having a plurality of unidirectional fibers for polishing impregnated with resin is arranged so that its longitudinal direction is substantially parallel to the rotation axis of the roll member, and is close to the roll surface of the roll member. Process,
And a second step of pressing the edge of the doctor blade against the roll surface. A method for cleaning a roll surface of a roll member rotating about a rotation axis. A first step in which a doctor blade having a plurality of unidirectional fibers for polishing impregnated with a resin is disposed so that the longitudinal direction thereof is substantially parallel to the rotation axis of the roll member, and close to the roll surface;
And a second step of pressing the blade end of the doctor blade against the roll surface. A method for finishing a roll surface of a roll member that rotates about a rotation axis.   The method according to claim 21 or 22, wherein the blade end portion of the doctor blade is kept in contact with the roll surface substantially continuously during operation of the roll member.   23. A method according to claim 21 or 22, wherein the first step comprises the step of arranging the doctor blade at an operating angle of approximately 25-30 degrees.   The method according to claim 21 or 22, wherein the pressure of the doctor blade in the second step is approximately 85 to 700 N / m.   The method according to claim 25, wherein the pressure of the doctor blade in the second step is approximately 175 to 440 N / m.   The method according to claim 22, wherein the surface roughness of the roll surface is approximately 0.025 to 0.20 μmRa.   28. The method according to claim 27, wherein the surface roughness of the roll member is approximately 0.05 to 0.13 [mu] mRa.   23. The method of claim 22, wherein the surface roughness of the roll surface is maintained at approximately 0.025 to 0.20 [mu] mRa during the useful life of the doctor blade.   30. The method of claim 29, wherein the surface roughness of the roll surface is maintained at approximately 0.05 to 0.13 [mu] mRa during the useful life of the doctor blade.   A method for producing a doctor blade, comprising a step of impregnating a composite material containing unidirectional fibers with a resin.   32. The method of manufacturing a doctor blade according to claim 31, further comprising a step of stacking a plurality of layers of the composite material impregnated with the resin to form a laminated structure.   33. The method of manufacturing a doctor blade according to claim 31 or 32, further comprising a step of curing the resin impregnated in the composite material by increasing temperature and pressure.   The doctor blade manufacturing method according to claim 33, further comprising a step of cutting the cured composite material into a plurality of doctor blades.   32. The method of manufacturing a doctor blade according to claim 31, wherein the unidirectional fibers are selected from the group consisting of glass fibers, ceramics, and mixtures thereof.   36. The method of manufacturing a doctor blade according to claim 35, wherein the unidirectional fibers include glass fibers.   32. The method of manufacturing a doctor blade according to claim 31, wherein the unidirectional fibers are mainly composed of long continuous fibers.   32. The method of manufacturing a doctor blade according to claim 31, wherein the unidirectional fibers are supplied from a unidirectional fabric in which the unidirectional fibers occupy at least 60% of the total weight.   The doctor blade manufacturing method according to claim 38, wherein at least 75% of the weight of the unidirectional fabric is unidirectional fibers. 40. The method of manufacturing a doctor blade according to claim 39, wherein at least 90% of the weight of the unidirectional fabric is unidirectional fibers.

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