CN111757782A

CN111757782A - Non-woven fabric coating machine

Info

Publication number: CN111757782A
Application number: CN201980014159.XA
Authority: CN
Inventors: 鬼头昌利; 金田安生; 加藤真; 佐藤友洋
Original assignee: Mitsubishi Paper Mills Ltd
Current assignee: Mitsubishi Paper Mills Ltd
Priority date: 2018-02-20
Filing date: 2019-02-14
Publication date: 2020-10-09
Also published as: JP2020054986A; JP7211831B2

Abstract

The invention provides a non-woven fabric coating machine, which can highly avoid the generation of defects such as pinholes caused by the penetration of a coating liquid when the coating liquid which enables the non-volatile component to be dispersed or dissolved in a medium is coated on a non-woven fabric. A non-woven fabric coating machine is characterized in that in the non-woven fabric coating machine provided with a coating mechanism for applying a coating liquid to a non-woven fabric, a conveying mechanism for supporting and conveying the non-woven fabric applied with the coating liquid on a conveying roller and a drying mechanism for drying the applied coating liquid, the surface of the conveying roller is provided with a concavo-convex shape and water repellency.

Description

Non-woven fabric coating machine

Technical Field

The present invention relates to a nonwoven fabric coater for coating a nonwoven fabric.

Background

A functional product is produced by applying a coating liquid in which nonvolatile components are dispersed or dissolved in a medium to a nonwoven fabric as a substrate. Examples of the nonvolatile components include resins, inorganic particles, organic particles, and the like; examples of the medium include water and an organic solvent. Examples of products to which functionality is imparted include separators for lithium ion batteries, filtration membranes, and the like.

In a lithium ion battery separator (hereinafter, may be simply referred to as "separator"), a thin separator having a thickness of 30 μm or less is required in order to reduce the volume ratio of the separator, which is a non-power generating element, in the battery. Among the filtration membranes, in order to improve filtration performance, it is desirable to be able to accommodate a large-area filtration membrane in a module having the same volume, and a thin filtration membrane is required.

In order to make the product thin, it is necessary to use a thin nonwoven fabric as a substrate. When a thin nonwoven fabric having a thickness of 30 μm or less is used as the base material, a phenomenon of "penetration of the coating liquid (pulling out け)" occurs. "penetration of the coating liquid" refers to a phenomenon in which the coating liquid oozes out to the opposite surface of the nonwoven fabric. Hereinafter, "penetration of the coating liquid" may be referred to as "penetration". Various problems arise due to permeation. Specifically, the following problems arise: the problem that the non-woven fabric is difficult to convey because the coating liquid seeps out is adhered to a conveying roller and a conveying support body; a problem that the application amount of the coating liquid to the nonwoven fabric is locally insufficient and a coating defect such as a pinhole (ピンホール) is generated; the coating liquid is temporarily transferred to a transport roller, the coating liquid on a support is transported, and the dried solid is transferred to a nonwoven fabric, which causes a problem of decrease in coating uniformity. In particular, in a separator for a lithium ion battery, a filtration membrane, and the like, since physical properties such as pore diameter are required to be uniform, the occurrence of coating defects such as pinholes and the reduction in coating uniformity are serious problems that degrade performance.

In order to solve many problems associated with infiltration, the following techniques have been proposed. For example, a method has been proposed in which a nonwoven fabric and a coating layer coated with a coating liquid are laminated on a transport support, and the transport support is peeled off after drying to obtain a product (see, for example, patent documents 1 to 4). As the transport support, dense paper and resin sheets that do not cause penetration are disclosed. Further, a method has been proposed in which 2 layers of nonwoven fabrics are laminated, the coating solution is impregnated into both of the nonwoven fabrics, the coating solution is solidified from one surface, and then the 2 layers of nonwoven fabrics are peeled off, and one of the two is obtained as a product (see, for example, patent document 5). However, these methods have a problem that since one of the used transport supports and the nonwoven fabric is discarded, the cost is increased, and a large amount of waste is generated.

Further, there has been proposed a method of preventing the deterioration of surface quality (facial sprines) associated with penetration by conveying a nonwoven fabric to which a coating liquid has been applied using a specific roller (see, for example, patent documents 6 to 8). Patent document 6 discloses a roller provided with grooves in a direction substantially parallel to the running direction. Further, patent document 7 discloses a roller having a diameter of 25mm or less. Further, patent document 8 discloses a smoothing roll. However, in the methods disclosed in patent documents 6 to 8, when a very thin nonwoven fabric is used as a base material, defects such as pinholes may occur, and the effects thereof still leave room for improvement.

Methods of preventing penetration by using a nonwoven fabric having specific physical properties (for example, see patent document 9) and methods of using a coating liquid having specific physical properties (for example, see patent documents 10 and 11) have also been proposed. However, in these methods, since the selection range of the nonwoven fabric and the coating liquid is narrow, the nonwoven fabric and the coating liquid may not be selected optimally from the viewpoint of product performance and cost. In particular, a nonwoven fabric having little permeation inevitably becomes a nonwoven fabric having low permeability to liquid and gas, and therefore, the nonwoven fabric is often a significant limitation in products intended for permeation of substances and ions, such as a separator and a filtration membrane for a lithium ion battery.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2005-268096

Patent document 2: japanese patent laid-open publication No. 2005-302341

Patent document 3: japanese patent laid-open publication No. 2013-186958

Patent document 4: japanese patent laid-open publication No. 2013-229118

Patent document 5: international publication No. 2008/153117 pamphlet

Patent document 6: japanese patent laid-open publication No. 2014-192027

Patent document 7: japanese patent laid-open publication No. 2014-192147

Patent document 8: japanese laid-open patent publication (JP 2015-8109)

Patent document 9: japanese patent laid-open publication No. 2013-154304

Patent document 10: japanese patent laid-open publication No. 2013-115031

Patent document 11: japanese patent laid-open publication No. 2014-44857

Disclosure of Invention

Technical problem to be solved by the invention

The invention provides a non-woven fabric coating machine which can highly avoid the generation of defects such as pinholes caused by the penetration of a coating liquid when the coating liquid which enables the non-volatile component to be dispersed or dissolved in a medium is coated on a non-woven fabric.

Means for solving the problems

Means for solving the problems of the present invention are as follows.

(1) A nonwoven fabric coater comprising a coating means for applying a coating liquid to a nonwoven fabric, a transport means for supporting and transporting the nonwoven fabric to which the coating liquid has been applied on a transport roller, and a drying means for drying the applied coating liquid, wherein the surface of the transport roller has a concavo-convex shape and water repellency ( water).

(2) The nonwoven fabric coater according to (1) above, wherein the transport roller is a roller whose surface is covered with a water-repellent uneven sheet (unevenness シート).

(3) The nonwoven fabric coater according to (1) above, wherein the feed roller is a roller having a surface made of polyolefin and a surface having a concavo-convex shape formed by machining.

(4) The nonwoven fabric applicator according to (1) above, wherein the feed roller is a roller having on its surface an uneven shape formed by a processing method selected from the group consisting of cutting and knurling (cutting ローレット), roll-embossing (pellet ローレット), and laser engraving.

(5) The nonwoven fabric coater according to (4), wherein the feed roller is a metal roller.

(6) The nonwoven fabric coating machine according to any one of the above (2) - (5), wherein the pitch (ピッチ) of the protrusions and recessions is 300-1000 μm, the gap/pitch (gap/ピッチ) is 0.3-0.6, the height of the protrusions and recessions is 50-200 μm, and the contact angle of the surface is 85 ° or more.

(7) The nonwoven fabric coater according to (1) above, wherein the feed roller is a roller subjected to thermal spray water repellent processing.

(8) The nonwoven fabric coater according to (1) above, wherein the feed roller is a roller subjected to water repellent plating by sandblasting (ブラスト).

(9) The nonwoven fabric coater according to (1) above, wherein the feed roller is a roller whose surface is covered with a water-repellent fabric (ファブリック).

Advantageous effects

The nonwoven fabric coater of the present invention can highly suppress the occurrence of defects such as pinholes due to the penetration of the coating liquid when the coating liquid in which the nonvolatile component is dispersed or dissolved in the medium is applied to the nonwoven fabric.

Drawings

Fig. 1 is a schematic view showing an example of a nonwoven fabric coater of the present invention.

Fig. 2 is a cross-sectional view showing an example of a pattern of a concave-convex shape formed on the conveying roller used in the present invention.

Fig. 3 is a cross-sectional view showing an example of a pattern of a concave-convex shape formed on the conveying roller used in the present invention.

Fig. 4 is a cross-sectional view showing an example of a pattern of a concave-convex shape formed on the conveying roller used in the present invention.

Fig. 5 is a cross-sectional view showing an example of the surface shape of the conveying roller subjected to the thermal spraying process.

Fig. 6 is a cross-sectional view showing an example of the surface shape of the conveying roll subjected to the thermal spray water repellent process.

Fig. 7 is a cross-sectional view (before damage) showing an example of the surface shape of the conveying roll subjected to the thermal spray water repellent process.

Fig. 8 is a cross-sectional view (after being damaged) showing an example of the surface shape of the conveying roller subjected to the thermal spray water repellent process.

Fig. 9 is a cross-sectional view showing an example of a pattern of the concave and convex shape in the conveying roller subjected to the blast processing used in the present invention.

Fig. 10 is a cross-sectional view showing an example of a pattern of a concave and convex shape in the conveying roller subjected to the blasting water-repellent plating process used in the present invention.

Fig. 11 is a view showing an example of a surface pattern of a glass cloth used for the water repellent cloth used in the present invention.

Fig. 12 is a cross-sectional view showing one example of the water-repellent fabric used in the present invention.

Detailed Description

The invention relates to a non-woven fabric coating machine for coating non-woven fabrics. More specifically, the present invention relates to a nonwoven fabric coater for coating a nonwoven fabric with a coating liquid in which nonvolatile components are dispersed or dissolved in a medium. The non-woven fabric coating machine of the invention is provided with a coating mechanism for applying a coating liquid to a non-woven fabric, a conveying mechanism for supporting and conveying the non-woven fabric applied with the coating liquid on a conveying roller, and a drying mechanism for drying the applied coating liquid.

Fig. 1 is a schematic view showing an example of a nonwoven fabric coater of the present invention. The nonwoven is pulled out of the nonwoven roll M by an unwinder. The nonwoven fabric is supported by a conveying roller T1 and conveyed to the coating mechanism H. Next, a coating liquid is applied to one surface of the nonwoven fabric by the coating mechanism H. Then, the nonwoven fabric travels while being supported by one or more of the conveying roller T2, conveying roller T3, and conveying roller T4 on the side opposite to the side to which the coating liquid is applied, and is dried by the drying mechanism D. The conveying roller T3 is a conveying roller immediately before the drying mechanism D, and is a conveying roller affected by heat from the drying mechanism D. The conveying roller T2 is a conveying roller present between the coating mechanism H and the conveying roller T3, and is a conveying roller that is not affected by heat from the drying mechanism D. The conveying roller T4 is a conveying roller inside the drying mechanism D, and is more affected by heat than the conveying roller T3.

The conveying roller is a roller used in the nonwoven fabric coating machine to determine the traveling direction of the nonwoven fabric or to stabilize the traveling of the nonwoven fabric. As the core material of the conveying roller, metal, plastic, fiber-reinforced plastic, or the like can be used. Examples of the metal include iron, stainless steel, aluminum, brass, and phosphor bronze. Examples of the plastic include fluorine-based resins; a silicone-based resin; a urethane resin; an acrylic resin; and olefin resins such as acrylonitrile-butadiene-styrene copolymer (ABS) resins, polyethylene, polypropylene, and ethylene-propylene copolymer resins. Examples of the fiber-reinforced plastic include a composite of a fiber material having a high elastic modulus such as carbon fiber, glass fiber, aramid (アラミド) fiber, boron fiber, and the like, a thermosetting resin such as an unsaturated polyester resin, an epoxy resin, a phenolic resin, a melamine resin, and the like, and a thermoplastic resin such as an acrylic resin such as polymethyl methacrylate, and the like.

The technical characteristic of the non-woven fabric coating machine of the invention is that the surface of the conveying roller has concave-convex shape and water repellency. Hereinafter, the "conveying roller having a surface with irregularities and water repellency" may be simply referred to as "conveying roller Z". The contact angle of water in the transport roller is preferably 85 ° or more. However, its maximum value is theoretically 180 °. When the contact angle of water is 85 ° or more, the nonwoven fabric is easily prevented from sticking to the conveying roller, and the penetrated coating liquid is hardly stuck to the conveying roller. The larger the contact angle, the more difficult the penetrated coating liquid is to adhere to the conveyance roller, and therefore, this is preferable. The contact angle was measured by automatically measuring the static contact angle at 10 points in a 5cm square range using a portable contact angle meter PG-X + (Fibo System AB, Sweden) in a room at room temperature of 23 ℃ and a relative humidity of 50%, and the average value was defined as the contact angle. The amount of distilled water added was 4.0. mu.L. As a method for imparting water repellency to a conveyance roller, a method of forming a concave-convex shape on a roller made of a water-repellent material; a method of coating the surface of the conveying roller with a material having water repellency by a method such as adhesion, coating, or plating.

The conveying roller z (i) is a roller whose surface is covered with a water-repellent uneven sheet. The material of the convex and concave pieces is not particularly limited, but a sheet made of polyethylene, polypropylene, fluororesin, or silicone resin having a water contact angle of 85 ° or more is preferable. Further, a sheet having a water repellent agent applied to the surface of the sheet having a water contact angle of less than 85 ° may be used. As the water repellent agent, a fluororesin or a silicone resin is preferable.

The conveying roller z (ii) is a roller whose surface is made of polyolefin and whose surface has a concavo-convex shape formed by machining. When the material of the surface of the conveying roller is polyolefin, it has water repellency and does not require any special treatment. A conveying roller formed into a concavo-convex shape by processing a metal roller or the like needs to be covered with a material made of polyolefin after the processing. Examples of the polyolefin include ultrahigh molecular weight polyethylene and polypropylene having a contact angle of water of 85 ° or more. The conveying roller z (ii) is more excellent in durability than the conveying roller z (i).

The conveying roller z (iii) is a roller having a surface with a concave-convex shape formed by a processing method selected from the group consisting of cutting knurling, roll knurling, and laser engraving. Among them, in the cutting and knurling process, the uneven shape can be formed in a short time, the processing can be performed in accordance with the optimum material and shape of the coating method, and the load on the conveying roller is small.

In the conveying rollers z (iii), when the material of the original roller surface itself has water repellency, no special treatment is necessary. When the uneven shape is formed by processing a metal roll or the like, water repellent treatment processing is performed thereafter. As the water-repellent treatment process, a method such as coating with a water-repellent resin, water-repellent plating, or the like can be used. From the viewpoint of durability, water repellent plating is preferable, and further, composite plating containing Polytetrafluoroethylene (PTFE) is suitably used.

In the conveying rollers z (i) to z (iii), the shape pattern in the concave-convex shape is not particularly limited. Examples of the convex portion shape include a cone, a polygonal pyramid, a dome (ドーム), a silk pattern ( mesh), a diamond (ダイヤモンド), and the like. In the conveying roller z (iii), from the viewpoint of ease of processing and reduction in contact area, silk or diamond is more preferable, and diamond is further preferable. Fig. 2 to 4 are cross-sectional views showing examples of the uneven pattern of the conveying rollers z (i) to z (iii).

In the conveying rollers Z (I) to Z (III), the pitch W1 of the projections and the depressions is preferably 300 to 1000 μm, more preferably 400 to 700 μm. In the present invention, the "pitch" of the concavities and convexities refers to the distance from the top to the top of the adjacent convexities. When the pitch W1 is 300 to 1000 μm, the effect that the penetrated coating liquid is not easily transferred to the conveying roller Z is easily obtained.

In the conveying rollers Z (I) to Z (III), the height h of the irregularities is preferably 50 to 200 μm, more preferably 75 to 120 μm. In the present invention, the "height" of the concavities and convexities is the height (distance in the Z direction) from the crests of the convexities to the troughs of the concavities. When the height h is 50 to 200 μm, the nonwoven fabric is easily prevented from sticking to the conveying roller and the uneven pattern is not transferred to the coating layer.

In the transport rollers Z (I) to Z (III), the concave-convex gap W2/pitch W1 is preferably 0.3 to 0.6, more preferably 0.4 to 0.5. In the present invention, as shown in fig. 2, the gap W2 is a distance connecting h/2 between the convex top of the adjacent convex portion and the middle point (middle point) of the concave trough. When the gap W2/pitch W1 is 0.3 to 0.6, the effect that the penetrated coating liquid is not easily transferred to the conveying roller is easily obtained.

The transport rolls z (iv) are rolls subjected to thermal spraying water repellent processing. The thermal spraying water repellent processing refers to processing in which water repellent processing is performed after thermal spraying processing is performed on the surface of the conveying roller material. The thermal spraying process is a process of forming a coating by bringing a coating material into a molten or semi-molten state and then colliding with the surface of a conveyor roll material to laminate the coating material, and thereby a conveyor roll having excellent wear resistance and heat resistance can be formed. As the coating material, metal, alloy, ceramic, plastic, glass, or the like can be used, and metal or ceramic is more preferable. Examples of the metal or ceramic include nickel-based, tungsten-based, and nickel-aluminum-based. In the thermal spraying process, a surface is formed with irregularities. In the thermal spraying of nickel and tungsten, Ra: 3-15 μm, Rz: a surface shape having moderate unevenness of about 30 to 100 μm and excellent abrasion resistance, and therefore, is suitably used.

The roller subjected to thermal spraying has a surface having irregularities, but has a surface having a period of irregularities having a fine interval of several tens of μm or less, and is conveyed while being brought into contact with the nonwoven fabric being conveyed in a state close to point contact. Therefore, the penetrated coating liquid is difficult to transfer onto the conveying roller.

In addition, the recessed portions having a fine-pitch uneven cycle formed by thermal spraying are usually subjected to a sealing treatment by a method such as resin application, thereby preventing adhesion of dirt and improving the performance of the coating film. In the present invention, the water repellent treatment after the thermal spraying treatment may be any water repellent treatment in which a water repellent resin such as a silicone resin or a fluorine-based resin is formed on the surface by a method such as coating, plating, or plasma treatment, but it is preferable to form a water repellent resin layer on the entire surface and form the water repellent resin layer so as to fill the fine recessed and projected periodic recesses formed by the thermal spraying treatment, and resin coating using a silicone resin or a fluorine-based resin is suitable. As the fluorine-based resin, Polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and the like are used. Examples of the silicone-based resin include silicone resins and silicone rubbers. Before the water repellent processing, the surface after the thermal spraying processing may be cleaned and polished to finely adjust the shape of the surface, thereby improving the adhesion with the water repellent resin. In order to improve the water-vapor-emission resistance (water-vapor-emission resistance) of the water-vapor-emitting resin layer, a scratch-resistant filler such as scaly mica, mica-like iron oxide, plate-like titanium oxide, and plate-like silicon carbide may be mixed as the filler.

In the conveying roller z (iv), as long as it is formed by thermal spraying, the uneven shape of the surface of the conveying roller subjected to thermal spraying water repellent processing may be any of various shapes. It is difficult to control the surface shape in detail by thermal spraying and the shape expression is also difficult, and the description will be made with reference to fig. 5 and 6. Fig. 5 is a cross-sectional view showing an example of the surface shape of the conveying roller subjected to the thermal spraying process. The surface shape 1 after thermal spraying has a fine uneven period of several tens of μm or less, expressed by β, in addition to the uneven period of 100 μm or more, expressed by α. Fig. 6 is a cross-sectional view showing an example of the surface shape of the conveying roll subjected to the thermal spraying water-repellent processing, and is a cross-sectional view showing a water-repellent processed surface shape 2 obtained by applying a water-repellent resin to the thermally sprayed surface shape 1 shown in fig. 5. As shown in fig. 6, the water-repellent resin layer is formed by applying a water-repellent resin so as to cover the entire surface, but the water-repellent resin layer is formed so as to fill the recessed portions of the surface shape 1 after the thermal spraying process.

In the nonwoven fabric coater of the present invention, the roll surface may be repeatedly subjected to physical contact to wear or may be damaged by sudden mechanical contact to cause damage during long-term use or maintenance work including cleaning work and the like. In such a case, if the roll is subjected to a normal water repellent process, the water repellency of the damaged portion may be reduced, and the effect of making it difficult to transfer the coating liquid onto the roll may be reduced. In such a case, the roller needs to be replaced with a new one in the worst case, but such a decrease in effect is unlikely to occur in the transport roller z (iv) subjected to the thermal spray water repellent process. Fig. 7 and 8 show the surface shape of the conveying roller subjected to the thermal spraying water repellent process before and after being damaged. These are the surface shapes of the conveying rolls having the surface shape 2 after the water repellent processing formed by performing the water repellent processing on the surface shape 1 after the thermal spraying processing. The water-repellent resin layer formed on the projections 3 of the surface shape before damage shown in fig. 7 is removed from the projections 4 of the surface shape after damage shown in fig. 8, and the surface shape 1 after thermal spraying is in a state not covered with the water-repellent resin layer. The convex portions (reference numeral 3 in fig. 7 and reference numeral 4 in fig. 8) are portions that are in point contact with the nonwoven fabric being conveyed, but in the present invention, even if the water-repellent resin layer of the convex portions 4 is not present, a sufficient water-repellent resin layer is still present around the convex portions, and therefore, the effect of suppressing the transfer by the penetration can be maintained well.

The conveying rolls z (v) are those subjected to sandblasting water-repellent plating. The sandblasting water-repellent plating process is a process in which the surface of the conveyor roll material is sandblasted and then subjected to a water-repellent plating process. The sandblasting is a processing method of grinding a surface of a material by jetting an abrasive to the surface of the material to deform the shape. The abrasive used in blasting is also called blasting material (blasting material), and any material other than metal particles and ceramic particles can be used as the blasting material as long as it can perform blasting. By controlling the kind of blasting material (particle diameter, composition, density, hardness, strength), blasting conditions (speed, blasting angle, blasting amount), and the like, a desired surface shape can be formed on the conveying roller.

The sandblasting water-repellent plating process is a water-repellent plating process performed after the sandblasting process. The surface of the sandblasted roll has a concavo-convex shape, but is usually in a state where surface contaminants such as oil and the like adhering to the surface of the roll before the blasting are completely removed, and is a surface made of only the roll material, and therefore, is suitable for the subsequent water-repellent plating process. That is, if the water repellent plating process is performed without performing the blasting process, the dirt on the roll surface causes poor plating, and prevents formation of a good plated coating film. Therefore, by performing the blasting before the water-repellent plating process, a strong plating film can be uniformly formed on the surface of the roll, and a conveying roll that can be used for a long period of time can be obtained.

The water-repellent plating process uses a process method of imparting water repellency to the surface by a composite plating technique. The composite plating technique is a technique in which a small amount of solid particles are contained in a plating solution during plating, and the solid particles are also deposited in a plating film (co-precipitation) during metal deposition, thereby imparting characteristics, which cannot be obtained by a normal plating film, to the plating film depending on the type of the solid particles. In the water-repellent plating process of the present invention, the water-repellent plating process is performed using solid particles to which water repellency is imparted as the solid particles. Examples of the solid particles to which water repellency is imparted include fluorine-based resins such as Polytetrafluoroethylene (PTFE) resins, and graphite fluoride.

In the conveying roller z (v), any shape may be used as long as it is formed by blasting, and the uneven shape of the surface of the conveying roller subjected to blasting water repellent plating processing is used. The description will be made with reference to fig. 9 and 10. Fig. 9 is a sectional view showing the surface shape 1' after the sandblasting process. Fig. 10 shows a surface shape 2' after water-repellent plating processing is performed on a concavo-convex shape having a period of 100 μm or more and 1000 μm or less, which is denoted by symbol a. As shown in fig. 10, the water-repellent plating process is performed so as to cover the entire surface. Period a uses the RSm value of the surface roughness parameter.

In the nonwoven fabric coater of the present invention, the roll surface may be repeatedly subjected to physical contact or sudden mechanical contact during long-term use or maintenance work including cleaning work and the like. In such a case, if the feed roller z (v) is subjected to the water-repellent plating process, it is less likely to be damaged. That is, the component contributing to water repellency in the water-repellent plating process of the present invention is solid particles that exhibit water repellency during composite plating, and the solid particles are not easily damaged because they are contained in a strong plating film. The conveyor roll subjected to the composite plating process is less likely to be damaged than a conveyor roll having a water-repellent resin layer formed by applying a water-repellent resin, has excellent abrasion resistance, and can maintain good water repellency for a long period of time.

In the blasting process for the conveying roller z (v), any of metallic blasting materials and non-metallic blasting materials can be used as the blasting material. The surface shape with moderate unevenness and Ra of about 5-30 μm is formed in the sand blasting processing. Thereby, adhesion of the coating liquid is suppressed, and a clean surface suitable for water-repellent plating is formed.

In the present invention, in the measurement of parameters relating to surface roughness such as Ra and period A, Rz, a contact surface roughness meter (SURFCOM FLEX (registered trademark), manufactured by tokyo co) was used with a cutoff value (カットオフ value) of 2.5mm and an evaluation length of 12.5mm, and was measured in accordance with JIS B0601: 2001 were measured.

As the composite plating used in the water repellent plating process, any combination of metal plating and solid particles imparting water repellency can be used, but as the composite plating capable of forming a strong and uniform plating film satisfactorily and obtaining high water repellency, nickel-PTFE composite plating can be suitably used.

The conveying roller z (vi) is a roller coated with a water repellent fabric. The water-repellent fabric is a fabric obtained by coating water-repellent resin on a fabric.

Fig. 11 is a view showing an example of a surface pattern of a glass cloth used for the water-repellent fabric of the conveying roller z (vi). In the present invention, as shown in fig. 11, the woven fabric has a portion where warp yarn a and weft yarn b overlap and a portion where they do not overlap, and has a gap c in the portion where they do not overlap, and has a concave-convex shape unique to the woven fabric. As the material constituting the fabric, there is no particular limitation. However, in order to be used as the conveying roller T4, it is preferable that the conveying roller T4 is made of a material that does not undergo irreversible thermal deformation at the temperature used in the drying means D, and examples thereof include glass fibers, aramid resin fibers, polyimide resin fibers, and phenol resin fibers.

The water-repellent resin used for the conveying rolls z (vi) is not particularly limited as long as it is a material that does not undergo irreversible thermal deformation at the temperature used in the drying means D, and examples thereof include fluorine-based resins such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and the like; silicone resins such as silicone resins and silicone rubbers.

In order to improve scratch resistance, a scratch resistant filler such as scaly mica, micaceous iron oxide, tabular titanium oxide, tabular silicon carbide and the like may be mixed as a filler in the water repellent resin.

Fig. 12 is a cross-sectional view showing one example of the water-repellent fabric used in the present invention. As shown in fig. 12, by coating the woven fabric composed of the warp yarn a and the weft yarn b with the water-repellent resin layer d, the gap c in the portion where the warp yarn a and the weft yarn b do not overlap as shown in fig. 11 disappears, and the penetrating coating liquid can be suppressed from entering the gap c.

Since the gaps c are covered with the water-repellent resin layer d, the number of warps and wefts (double hand) is preferably 5.6tex to 200tex, the weaving density is preferably 30 to 25mm, and 80 to 25mm, and the weave texture is preferably a plain weave (a flat-coated article), a satin weave (a brown coated article), or a twill weave ( mesh). The count, weave density may vary in the warp and weft. Since the contact area between the conveying roller and the nonwoven fabric can be reduced, Ra on the surface of the conveying roller is preferably 3 to 30 μm. Further, even if the conveying roller z (vi) is damaged due to physical contact during long-term use or maintenance work, the conveying roller z (vi) can be easily replaced, and a good effect can be maintained for a long period of time by easy maintenance.

The following advantageous effects can be obtained by the conveying roller Z. That is, since the penetrated coating liquid is difficult to transfer to the conveying roller, the nonwoven fabric is difficult to adhere to the conveying roller, and the conveyance becomes stable. Further, coating defects such as pinholes are less likely to occur in the obtained coating layer. Further, the coating liquid transferred onto the transfer roller is prevented from being transferred onto the nonwoven fabric again, and the coating layer is prevented from becoming uneven. The reason for obtaining these effects is that the contact area between the conveying roller and the nonwoven fabric can be reduced by the irregularities on the surface of the conveying roller.

In the present invention, the conveying roller Z conveys the nonwoven fabric from the step of applying the coating liquid to one surface of the nonwoven fabric (coating step) to the step of drying the nonwoven fabric (drying step). At this time, the surface of the nonwoven fabric opposite to the surface to which the coating liquid is applied is appropriately supported by the conveying roller. The conveying roller Z is used as at least one of the conveying rollers T2 to T4. Therefore, the conveying roller Z may be used for all of the conveying rollers T2 to T4. As for the conveying roller T2 present between the coating mechanism H and the conveying roller T3 immediately before the drying mechanism D, since it is a conveying roller that is not affected by heat from the drying mechanism D, any conveying roller having a surface with irregularities and having water repellency may be used.

The conveying roller z (i) and the conveying roller z (ii) may function as the conveying roller T2 and the conveying roller T3. Further, the heat resistance of the conveying rollers z (iii) is more excellent than that of the conveying rollers z (i) and z (ii). Therefore, the conveying roller z (iii) can be used not only as the conveying roller T2 and the conveying roller T3 but also as the conveying roller T4. Particularly, in the case of a metal roll having excellent heat resistance, it is suitable for the transport roll T4. In the drying mechanism D, a process at a higher drying temperature can be performed.

The conveying rollers z (iv) to z (vi) may have high heat resistance, and may be used not only as the conveying rollers T2 and T3 but also as the conveying rollers T4 inside the drying mechanism D. By using the conveyor roller T4, the drying temperature of the drying mechanism D can be increased, the degree of freedom of the process can be increased, and productivity can be improved.

Further, when the coating liquid adheres to the conveying roller T4 for some reason and the dirt is fixed, it is necessary to clean the surface, and in this cleaning, a physical force may be applied to the surface of the conveying roller to remove the fixed matter. By using the conveying roller T4 having improved wear resistance, the conveying roller surface is less likely to be damaged even if the above-described physical contact exists on the surface of the T4 roller, and the transfer inhibiting effect of the penetration is maintained well. It is also preferable to use the conveyance rollers z (iv) to z (vi) having excellent wear resistance as conveyance rollers at positions on the surface where mechanical contact is likely to occur and at positions where mechanical contact is necessary during maintenance work, such as surface cleaning.

In the present invention, the coating mechanism H is not particularly limited. However, in the case where an excessive amount of the coating liquid permeates, it is difficult to avoid adverse effects caused by permeation even according to the present invention, and therefore it is preferable to use a coating mechanism that is difficult to generate dynamic pressure in the thickness direction. The dynamic pressure in the thickness direction becomes a cause of penetration of a large amount of the coating liquid. Specifically, a coating mechanism such as a kiss gravure coater, kiss roll coater, die coater, curtain coater, or spray coater is preferably used.

In the present invention, the drying mechanism D is also not particularly limited. An air dryer that blows hot air or dry air onto the surface of the nonwoven fabric to dry the nonwoven fabric; a cylinder dryer for heating and drying the nonwoven fabric by bringing the nonwoven fabric into contact with the surface of the heated metal cylinder; and a drying means such as an infrared dryer for heating the nonwoven fabric with infrared rays.

From the viewpoint of a small amount of coating liquid adhering to the surface and the viewpoint of rapid drying, it is preferable that the surface opposite to the surface to which the coating liquid is applied be dried first.

In the present invention, the nonwoven fabric is not particularly limited. However, when a thick nonwoven fabric is used, penetration of the coating liquid is inherently difficult to occur, and there is no motivation to use the technique of the present invention. On the contrary, when a thin nonwoven fabric, specifically, a nonwoven fabric having a thickness of 30 μm or less is used, the uniformity of application can be greatly improved by the present invention.

The conveying roller T1 existing before the application mechanism H is not particularly limited, and any of metals, resins, and fiber-reinforced plastics can be used. Examples of the metal include iron, stainless steel, aluminum, brass, and phosphor bronze. Examples of the resin include fluorine-based resins; a silicone-based resin; a urethane resin; an acrylic resin; an ABS resin; polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer resins. Examples of the fiber-reinforced plastic include a composite of a material having a high elastic modulus such as carbon fiber, glass fiber, aramid fiber, or boron fiber, a thermosetting resin such as an unsaturated polyester resin, an epoxy resin, a phenol resin, or a melamine resin, and a thermoplastic resin such as an acrylic resin such as polymethyl methacrylate.

Inside the drying mechanism D and after the drying mechanism D, at least a part of the medium is evaporated, the conveying roller for supporting the nonwoven fabric after the applied coating liquid loses fluidity does not need to have a penetrating transfer inhibiting effect. That is, a conveying roller having no uneven shape and water repellency can be used. However, as the conveying roller used inside the drying mechanism D, it is necessary to use a conveying roller having resistance to the temperature inside the drying mechanism D.

Examples

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[ nonwoven Fabric ]

Using a polyethylene terephthalate having a fineness of 0.1dtex and a cut length of 3mm70 parts by mass of a bulk short fiber (ステープル), 30 parts by mass of a polyethylene terephthalate binder fiber short fiber having a fineness of 0.2dtex and a cut length of 3mm, and 8g/m in weight per square meter (basis weight) obtained by applying strength and adjusting thickness by hot calendering at a surface temperature of 200 DEG C²And a wet-type papermaking nonwoven fabric having a thickness of 12 μm.

[ coating solution ]

A coating solution was prepared which contained 100 parts by mass (in terms of solid content) of alumina hydrate (boehmite), 2.0 parts by mass (in terms of solid content) of a latex of an acrylic polymer, 0.4 parts by mass (in terms of solid content) of a sodium salt of a maleic acid-acrylic acid copolymer, and 0.2 parts by mass (in terms of solid content) of sodium carboxymethyl cellulose (CMC-Na), and the medium was water. The coating liquid had a solid content concentration of 20% by mass. As CMC-Na, CMC-Na having a viscosity of 7000 mPasec at 20 ℃ in a 1 mass% aqueous solution was used.

[ Water repellency measurement ]

In the present invention, the water repellency was measured automatically at 10 static contact angles in a 5cm square range in a room at room temperature of 23 ℃ and a relative humidity of 50% by using a portable contact angle meter PG-X + (Fibo System AB, Sweden), and the average value thereof was used. The amount of distilled water added was 4.0. mu.L.

< conveying roller Z (I) >

[ example I-1]

The WET coating amount of the nonwoven fabric with the medium (water) was 50g/m by the apparatus schematically shown in FIG. 1²The coating liquid is applied. As the coating mechanism H, a die coater was used. As the drying means D, hot air was blown onto the non-woven fabric side to which the coating solution was not applied by using a single-sided air dryer having an effective length of 30cm, and then hot air was blown onto the non-woven fabric side to which the coating solution was applied by using two single-sided air dryers having an effective length of 30 cm. As the conveying roller T2 and the conveying roller T3 located between the coating mechanism H and the drying mechanism D, rollers having a diameter of 60mm with an aluminum alloy as a core material covered with a concave-convex Polyethylene (PE) sheet were used. As the conveying roller T4, a roller having a diameter of 60mm and having an aluminum alloy as a core material was used. The concave-convex PE sheets are not overlapped with each other and no gap is generatedThe mode of (1) is to use spray glue for sticking. In the uneven PE sheet, the projections were conical in shape, the pitch W1 of the projections and the depressions was 600. mu.m, the height h of the projections and the depressions was 100. mu.m, the gap W2/pitch W1 of the projections and the water contact angle were 88 °. The coating speed was 2 m/min.

[ example I-2]

A nonwoven fabric was coated in the same manner as in example I-1, except that an embossed polypropylene (PP) sheet was used instead of the embossed PE sheet. In the embossed PP sheet, the pitch W1 of the projections and depressions was 700 μm, the height h of the projections and depressions was 120 μm, the gap W2/pitch W1 of the projections and depressions was 0.40, and the contact angle of water was 94 °.

[ example I-3]

A nonwoven fabric was coated in the same manner as in example I-1, except that an uneven Polytetrafluoroethylene (PTFE) sheet was used instead of the uneven PE sheet. In the uneven PTFE sheet, the pitch W1 of the unevenness was 600 μm, the height h of the unevenness was 100 μm, the gap W2/pitch W1 of the unevenness was 0.45, and the contact angle of water was 110 °.

[ example I-4]

A nonwoven fabric was coated in the same manner as in example I-1 except that the pitch W1 between the irregularities, the height h between the irregularities, and the gap W2/pitch W1 between the irregularities, were 450 μm, 110 μm, and the contact angle was 90 degrees, respectively, in the uneven PE sheet.

[ example I-5]

A nonwoven fabric was coated in the same manner as in example I-1 except that the uneven PE sheet had an uneven pitch W1 of 560 μm, an uneven height h of 200 μm, an uneven gap W2/pitch W1 of 0.57 and a water contact angle of 89 °.

[ example I-6]

A nonwoven fabric was coated in the same manner as in example I-1 except that the pitch W1 between the irregularities, the height h between the irregularities, and the gap W2/pitch W1 between the irregularities, were 600 μm, 50 μm, 0.60, and the contact angle of water was 89 ℃ in the uneven PE sheet.

[ examples I-7]

A nonwoven fabric was coated in the same manner as in example I-1 except that the pitch W1 between the irregularities was changed to 1500 μm, the height h was changed to 300 μm, and the gap W2/pitch W1 was changed to 0.57 in the uneven PE sheet. The contact angle of water was 89 °.

[ examples I to 8]

A nonwoven fabric was coated in the same manner as in example I-1 except that the pitch W1 between the irregularities of the irregular PE sheet was 600. mu.m, the height h was 100. mu.m, and the gap W2/pitch W1 was 0.22. The contact angle of water was 89 °.

[ examples I-9]

A nonwoven fabric was coated in the same manner as in example I-1 except that the pitch W1 between the irregularities of the irregular PE sheet was 300. mu.m, the height h was 100. mu.m, and the gap W2/pitch W1 was 0.60. The contact angle of water was 89 °.

[ examples I-10]

A nonwoven fabric was coated in the same manner as in example I-1 except that the pitch W1 between the irregularities of the irregular PE sheet was 1000. mu.m, the height h was 120. mu.m, and the gap W2/pitch W1 was 0.50. The contact angle of water was 89 °.

[ example I-11]

A nonwoven fabric was coated in the same manner as in example I-1 except that the pitch W1 between the irregularities of the irregular PE sheet was 700 μm, the height h was 75 μm, and the gap W2/pitch W1 was 0.40. The contact angle of water was 89 °.

[ examples I-12]

A nonwoven fabric was coated in the same manner as in example I-1 except that the pitch W1 between the irregularities of the irregular PE sheet was 500. mu.m, the height h was 100. mu.m, and the gap W2/pitch W1 was 0.45. The contact angle of water was 89 °.

[ examples I-13]

A nonwoven fabric was coated in the same manner as in example I-1 except that the pitch W1 between the irregularities of the irregular PE sheet was 600. mu.m, the height h was 100. mu.m, and the gap W2/pitch W1 was 0.25. The contact angle of water is 85 °.

[ examples I to 14]

A nonwoven fabric was coated in the same manner as in example I-1 except that the pitch W1 between the irregularities of the irregular PE sheet was 600. mu.m, the height h was 130. mu.m, and the gap W2/pitch W1 was 0.60. The contact angle of water is 80 °.

Comparative example I-1

A nonwoven fabric was coated in the same manner as in example I-1 except that a PE sheet having no unevenness was used in place of the uneven PE sheet. The contact angle of water was 89 °.

Comparative example I-2

A nonwoven fabric was coated in the same manner as in example I-3, except that a PTFE sheet having no unevenness was used in place of the uneven PTFE sheet. The contact angle of water is 112 °.

Comparative example I-3

Coating of a nonwoven fabric was carried out in the same manner as in example I-1, except that metal rolls made of an aluminum alloy were used as the conveying rolls T2 and T3 located between the coating mechanism H and the drying mechanism D, and the roll surfaces were not covered with the uneven PE sheet. The contact angle of the metal roll was 80 °.

[ evaluation ]

The nonwoven fabric after coating was scanned over a 100mm × 100mm area with a transmission scanner having a resolution of 600dpi, and pixels having a high luminance of 5 σ were regarded as pinholes based on the mode of the obtained luminance histogram, and the uniformity was determined based on the number thereof. In the case where a plurality of pixels having high luminance of 5 σ or more are adjacent to each other, it is regarded as 1 pinhole. The smaller the number of pin holes, the more uniform the coating can be judged. Samples were taken after 10m of coating. The results are shown in Table 1.

[ Table 1]

In examples I-1 to I-14 in which the surfaces of the conveying roller T2 and the conveying roller T3 were covered with water-repellent concave and convex pieces, there were less than 500 pinholes. In contrast, in comparative examples I-1 to I-3, the surfaces of the conveying roller T2 and the conveying roller T3 were not covered with the water-repellent uneven sheet, and therefore the contact between the conveying roller T2 and the conveying roller T3 and the nonwoven fabric was increased, and the number of pinholes was more than 500.

Comparing examples I-1 to I-14, 493 pinholes were present in example I-7 with a spacing W1 of 1500 μm, 475 pinholes were present in example I-8 with a gap W2/spacing W1 of 0.22, 460 pinholes were present in example I-13 with a gap W2/spacing W1 of 0.25, and 480 pinholes were present in example I-14 with a contact angle of 80 °; on the other hand, in examples I-1 to I-6 and I-9 to I-12, in which the pitch W1 is 300 to 1000 μm, the gap W2/pitch W1 is 0.3 to 0.6, the height h of the asperities is 50 to 200 μm, and the contact angle of the asperity sheet is 85 ° or more, the number of pinholes is 0 to 70, and is very small.

In examples I-1 to I-14, the coating speed was limited to 2m/min due to the effective length of the drying means, but since the penetration of the coating liquid is a phenomenon that deteriorates with time, it is advantageous to increase the coating speed, and if an air dryer having a long effective length is used, the speed can be increased easily.

< conveying roller Z (II) >

[ example II-1]

The WET coating amount of the nonwoven fabric containing the medium (water) was 50g/m by a nonwoven fabric coater schematically shown in FIG. 1²The coating liquid is applied. As the coating mechanism H, a die coater was used. As the drying means D, hot air was blown onto the non-woven fabric side to which the coating solution was not applied by using a single-sided air dryer having an effective length of 30cm, and then hot air was blown onto the non-woven fabric side to which the coating solution was applied by using two single-sided air dryers having an effective length of 30 cm. The drying temperature was 100 ℃. As the conveying roller T2 located between the coating mechanism H and the conveying roller T3 immediately before the drying mechanism D, a roller of 60mm diameter having an aluminum alloy as a core material covered with a concave-convex Polyethylene (PE) sheet was used. The concave-convex PE sheets are adhered by spraying glue in a manner that the concave-convex PE sheets are not overlapped with each other and gaps are not generated. In the uneven PE sheet, the projections were conical in shape, the pitch W1 of the projections and the depressions was 600. mu.m, the height h of the projections and the depressions was 100. mu.m, the gap W2/pitch W1 of the projections and the water contact angle were 88 °. The coating speed was 30 m/min.

As the conveying roller T3 immediately before the drying means D and the conveying roller T4 inside the drying means D, a conveying roller having a diamond pattern formed as an uneven shape on the surface by cutting and knurling on a roller made of ultra-high molecular weight polyethylene having a diameter of 60mm was used.

The cutting and knurling process performed on the surfaces of the conveying roller T3 and the conveying roller T4 was performed so that a flat region was left on the convex top portion of the uneven shape with a pitch W1 of 500 μm, a height h of 190 μm, and a gap W2 of 226 μm, as shown in fig. 3. The contact angle of water is 88 deg..

[ example II-2]

The nonwoven fabric was coated in the same manner as in example II-1 except that the pattern of the cutting and knurling process performed on the surfaces of the conveying roller T3 and the conveying roller T4 was processed so that the pitch W1 was 364 μm, the height h was 157 μm, and the gap W2 was 182 μm, as shown in fig. 4, and no flat region remained at the top. The contact angle of water is 88 deg..

[ example II-3]

The nonwoven fabric was coated in the same manner as in example II-1 except that the pattern of the cutting and knurling process performed on the surfaces of the conveying roller T3 and the conveying roller T4 was processed so that the pitch W1 was 210 μm, the height h was 94 μm, and the gap W2 was 105 μm, as shown in fig. 4, and no flat region remained on the top. The contact angle of water is 88 deg..

[ example II-4]

The nonwoven fabric was coated in the same manner as in example II-1 except that the pattern of the cutting and knurling performed on the surfaces of the conveying roller T3 and the conveying roller T4 was processed so that the pitch W1 was 940 μm, the height h was 400 μm, and the gap W2 was 470 μm, and no flat area remained on the top, as shown in fig. 4. The contact angle of water is 88 deg..

[ example II-5]

Coating of a nonwoven fabric was performed in the same manner as in example II-1 except that the surface processing pattern of the conveying roller T3 and the conveying roller T4 was processed by laser engraving without cutting knurling so that the pitch W1 was 600 μm, the height h was 100 μm, and the gap W2 was 270 μm as shown in fig. 4 and no flat region remained at the top. The contact angle of water is 88 deg..

[ examples II-6]

The coating of the nonwoven fabric was carried out in the same manner as in example II-1 except that the surface processing pattern of the conveying roller T3 and the conveying roller T4 was processed by laser engraving without cutting knurling so that the pitch W1 was 940 μm, the height h was 120 μm, and the gap W2 was 475 μm as shown in fig. 4 and no flat region remained at the top. The contact angle of water is 88 deg..

[ examples II-7]

As the conveying roller T3 and the conveying roller T4, rollers are used: a nonwoven fabric was coated in the same manner as in example II-1 except that a pyramid (ピラミッド) pattern was formed as an uneven shape on the surface of a roll made of stainless steel by milling (ミール engraving) without knurling, a heat-shrinkable polypropylene film was wound around the roll after the processing, and the roll was attached and covered by blowing with a blower at a drying temperature of 80 ℃ while the pitch W1 was 700 μm, the height h was 120 μm, the gap W2 was 350 μm, and the height h was 700 μm as shown in fig. 4. The contact angle of water is 92 °.

[ examples II-8]

The nonwoven fabric was coated in the same manner as in example II-1 except that the feed roll T3 and the feed roll T4 were formed into an uneven shape having a pitch W1 of 940 μm, a height h of 120 μm, and a gap W2 of 475 μm by laser engraving without cutting and knurling on a roll made of polypropylene instead of an ultra-high-molecular-weight polyethylene roll. The contact angle of water was 93 °.

[ examples II-9]

A nonwoven fabric was coated in the same manner as in example II-1 except that a concave-convex polyethylene sheet having a pitch W1 of 600 μm, a height h of 100 μm, and a gap W2 of 270 μm was fixed to the surface of an aluminum alloy roll having a diameter of 60mm with a polyimide tape so as not to overlap each other and to form a gap, and that the transport rolls were used as the transport roll T3 and the transport roll T4. The shape of the convex portion of the embossing (エンボス processing) is a conical shape. The contact angle of water is 90 °.

Comparative example II-1

A nonwoven fabric was coated in the same manner as in example II-1 except that ultra-high-molecular-weight polyethylene rolls having a diameter of 60mm and having no uneven surface were used as the conveying rolls T3 and T4. The contact angle of water is 88 deg..

Comparative example II-2

A nonwoven fabric was coated in the same manner as in example II-1 except that a diamond pattern was formed as an uneven shape on the surface of a roller made of stainless steel having a diameter of 60mm as a conveying roller T3 and a conveying roller T4 by milling and engraving, as shown in fig. 4, such that the pitch W1 was 580 μm, the height h was 250 μm, the gap W2 was 260 μm, and no flat region remained on the top. The contact angle of water is 60 °.

The results of evaluation of pinholes and uneven coating (ムラ) in the observation of the coated surface after the nonwoven fabric was coated are shown in table 2.

In examples II-1 to II-8, a good coating surface was formed.

In example II-9, in the conveying roller T4 in the drying mechanism D, the uneven PE sheet fixed on the surface of the conveying roller was deformed by heat, and streaks were generated on the coated surface. The conveying roller Z covered with the uneven PE sheet can be used as the conveying roller T2 and the conveying roller T3, but is difficult to use as the conveying roller T4.

Further, in comparative example II-1 and comparative example II-2, the surfaces of the conveying roller T3 and conveying roller T4 were stained due to the penetration of the coating liquid, and streaks were generated on the coated surface due to the reverse transfer thereof.

< conveying roller Z (III) >

[ example III-1]

The nonwoven fabric was coated with a WET containing medium (water) in an amount of 50g/m by an apparatus schematically shown in FIG. 1²The coating liquid is applied. As the coating mechanism H, a die coater was used. As the drying means D, hot air was blown onto the non-woven fabric side to which the coating solution was not applied by using a single-sided air dryer having an effective length of 30cm, and then hot air was blown onto the non-woven fabric side to which the coating solution was applied by using two single-sided air dryers having an effective length of 30 cm. As the conveying roller T2 positioned between the coating mechanism H and the conveying roller immediately before the drying mechanism D, a roller having a diameter of 60mm with an aluminum alloy as a core material, which is covered with a concave-convex Polyethylene (PE) sheet, was used. The concave-convex PE sheets are adhered by spraying glue in a manner that the concave-convex PE sheets are not overlapped with each other and gaps are not generated. In the uneven PE sheet, the unevennessThe shape of the section was conical, the pitch W1 of the concavities and convexities was 600 μm, the height h of the concavities and convexities was 100 μm, the gap W2/pitch W1 of the concavities and convexities was 0.45, and the contact angle of water was 88 °. The coating speed was 30 m/min.

As the conveying roller T3 and the conveying roller T4 immediately before and inside the drying means D, a conveying roller was used which was formed by forming a diamond pattern as an uneven shape on the surface by cutting knurling on a stainless steel roller and then subjected to a PTFE composite plating treatment to perform a water repellent treatment.

The surfaces of the conveying roller T3 and the conveying roller T4 were subjected to cutting and knurling so that flat regions were left on the convex tops of the uneven shape at a pitch W1 of 580 μm and a height h of 200 μm as shown in fig. 3.

[ example III-2]

The nonwoven fabric was coated in the same manner as in example III-1 except that the pattern of the cutting and knurling performed on the surfaces of the conveying roller T3 and the conveying roller T4 was processed so that the pitch W1 was 580 μm and the height h was 250 μm as shown in fig. 4 and no flat region remained at the top.

[ example III-3]

Coating of a nonwoven fabric was carried out in the same manner as in example III-1, except that the method of water repellency treatment for the conveying roller T3 and the conveying roller T4 was changed to the PTFE resin coating treatment.

[ example III-4]

Coating of a nonwoven fabric was carried out in the same manner as in example III-1, except that a roll made of an aluminum alloy was used instead of the roll made of stainless steel.

[ example III-5]

A nonwoven fabric was coated in the same manner as in example III-4 except that the cutting knurling process in example III-4 was not performed, but the roll knurling process was performed, and the uneven shape having the pitch W1 of 500 μm and the height h of 250 μm was formed.

[ examples III-6]

A nonwoven fabric was coated in the same manner as in example III-1, except that a concave-convex shape having a pitch W1 of 600 μm and a height h of 100 μm was formed by laser engraving without performing a cutting knurling process, and the water repellent treatment was changed to PTFE resin coating.

[ examples III to 7]

A nonwoven fabric was coated in the same manner as in example III-1 except that a teflon (registered trademark) sheet was embossed at a pitch W1 of 600 μm and a height h of 250 μm, and a roll obtained by fixing the sheet to the surface of an aluminum alloy roll using a polyimide tape was used for the feed roll T3 and the feed roll T4. The shape of the embossed projection is a conical shape.

[ examples III to 8]

A nonwoven fabric was coated in the same manner as in example III-1, except that a roll in which an uneven PE sheet having a pitch W1 of 600 μm and a height h of 100 μm was fixed to the surface of an aluminum roll was used for the conveying roll T3 and the conveying roll T4. The shape of the embossed projection is a conical shape.

Comparative example III-1

A nonwoven fabric was coated in the same manner as in example III-1, except that a stainless steel roll having no uneven surface was used for the conveying roll T3 and the conveying roll T4.

Comparative example III-2

A nonwoven fabric was coated in the same manner as in example III-1, except that a stainless steel roll having an uneven surface formed by cutting and knurling was used for the conveying roll T3 and the conveying roll T4. The surface was not subjected to water repellency treatment.

The results of observation of the coated surface after coating the nonwoven fabric and evaluation of pinholes and coating unevenness are shown in table 3.

In examples III-1 to III-7, a good coating surface was formed. However, in example III-5, the aluminum alloy roll had dimensional changes (strain) due to the roll knurling process, and variations in the pass line of the sheet during conveyance were observed. However, no effect on the coated side was found.

In the laser engraving process used in example III-6, the production takes time compared with the cutting and knurling process, and the height h is also limited.

In the conveying roller T3 and the conveying roller T4 used in example III-7, the teflon sheet was damaged and had to be replaced.

In example III-8, in the conveying roller T4 in the drying mechanism D, the PE sheet formed on the surface of the conveying roller was deformed by heat, and streaks were generated on the coated surface. The conveying roller Z covered with the uneven PE sheet can be used as the conveying roller T2 and the conveying roller T3, but is difficult to use as the conveying roller T4.

In comparative example III-1 and comparative example III-2, the surfaces of the transport roller T3 and the transport roller T4 were contaminated with the permeate liquid, and streaks were generated on the coated surface by the reverse transfer.

< conveying roller Z (IV) >

[ example IV-1]

Fig. 1 is a schematic view showing an example of the nonwoven fabric coater of the present invention. This is an apparatus for feeding a nonwoven fabric from a nonwoven fabric roll M made of the nonwoven fabric, conveying the nonwoven fabric by a conveying mechanism made of a conveying roller T1 to a conveying roller T4, and applying and drying the coating liquid by an application mechanism H and a drying mechanism D.

As the coating means H, a die coater was used so that the WET coating amount of the medium (water) was 50g/m²Coating is performed in the manner of (1). As the drying means D, hot air was blown onto the non-woven fabric side to which the coating solution was not applied by using a single-sided air dryer having an effective length of 30cm, and then hot air was blown onto the non-woven fabric side to which the coating solution was applied by using two single-sided air dryers having an effective length of 30 cm. The drying temperature was 100 ℃.

As the conveying roller T2 located between the coating mechanism H and the conveying roller T3 immediately before the drying mechanism D, a roller of 60mm diameter having an aluminum alloy as a core material covered with a concave-convex Polyethylene (PE) sheet was used. The concave-convex PE sheets are adhered by spraying glue in a manner that the concave-convex PE sheets are not overlapped with each other and gaps are not generated. The coating speed was 30 m/min.

As the conveying roller T3 immediately before the drying mechanism D and the conveying roller T4 inside the drying mechanism D, a roller subjected to thermal spray water repellent processing was used. The thermal spraying is nickel-based thermal spraying, and a roll coated with a silicone-based resin is used for water repellent processing. Surface roughness Ra: 10 μm, Rz: 75 μm. The contact angle was 106 °.

When the coated surface of the nonwoven fabric was observed, no pinholes or coating unevenness due to permeation was observed, and a good coated surface was formed.

For the purpose of confirming the durability, the coating liquid was forcibly fixed to the conveying roller T4 of the drying mechanism D, and then the cleaning and removing operation was performed, and the coating was performed again in the same manner as described above, and the coated surface was observed. The washing removal operation is performed by washing with water, and the removal of the fixed matter is performed by applying a physical force to the remaining many coating liquid fixed portions by a metal blade. The fixed material in the recess is removed by attaching an adhesive sheet.

The coated surface after coating was observed to form a coated surface as good as before the cleaning operation.

The roller T4 was further subjected to the above-described fixing-washing removal operation 30 times, and then was coated again in the same manner as described above, and the coated surface was observed to form a coated surface that was as good as the initial coated surface.

Comparative example IV-1

A nonwoven fabric was coated and the coated surface was observed in the same manner as in example 30, except that in example IV-1, a roll subjected to only thermal spraying but not water repellent processing was used instead of the roll subjected to thermal spraying water repellent processing, on the transfer roll T3 immediately before the drying mechanism D and the transfer roll T4 inside the drying mechanism D. The surface roughness of the roll subjected to only thermal spraying processing was Ra: 15 μm, Rz: 100 μm, contact angle 80 deg..

When the coated surface of the nonwoven fabric was observed, pinholes and coating unevenness due to permeation were observed, and a good coated surface could not be formed.

Comparative example IV-2

A nonwoven fabric was coated and the coated surface was observed in the same manner as in example 30, except that in example IV-1, a roll having only water repellent finish without thermal spraying was used as the transport roll T3 immediately before the drying means D and the transport roll T4 inside the drying means D. The surface roughness of the roll subjected only to water repellent processing was Ra: 1 μm, Rz: 5 μm, contact angle 102 deg..

< conveying roller Z (V) >

Example V-1

As the conveying roller T3 immediately before the drying mechanism D and the conveying roller T4 inside the drying mechanism D, a roller subjected to sandblast water-repellent plating processing was used. The sand blasting uses glass beads as a blasting material, and the water repellent plating uses nickel-PTFE composite plating. Surface roughness Ra: 15 μm. The contact angle was 120 °. The period A was 500. mu.m.

For the purpose of confirming the durability, the coating liquid was forcibly fixed to the conveying roller T4 of the drying mechanism D, and then the cleaning and removing operation was performed, and the coating was performed again in the same manner as described above, and the coated surface was observed. The cleaning and removing operation is performed by water washing. When the coating liquid fixed portion remains, the fixed object is removed by applying a physical force with a cloth wiper.

Comparative example V-1

The nonwoven fabric was coated and the coated surface was observed in the same manner as in example V-1, except that in example V-1, the roll subjected to the water-repellent coating process by sandblasting only was used instead of the roll subjected to the water-repellent coating process by sandblasting immediately before the drying means D in the conveying roll T3 and the conveying roll T4 inside the drying means D. The surface roughness of the roll subjected to only the blasting was Ra: 15 μm, contact angle 60 deg.. The period A was 500. mu.m.

As a result of the application of the nonwoven fabric, the coating liquid permeated through the transfer roller T3 and the transfer roller T4 was transferred, pinholes and coating unevenness were observed in the coated surface, and a good coated surface could not be formed.

Comparative example V-2

The nonwoven fabric was coated and the coated surface was observed in the same manner as in example V-1, except that in example V-1, the conveying roller T3 immediately before the drying device D and the conveying roller T4 inside the drying device D were rollers subjected to only the water-repellent plating process without performing the blasting process. The surface roughness of the roll subjected only to the water-repellent plating process was Ra: 1 μm, contact angle 120 °. The period A was 150. mu.m.

As a result of the application of the nonwoven fabric, the coating liquid permeated through the transfer roller T3 and the transfer roller T4 was transferred, pinholes and coating unevenness were observed on the coated surface, and a good coated surface could not be formed.

< conveying roller Z (VI) >

[ example VI-1]

The WET coating amount of the nonwoven fabric containing the medium (water) was 50g/m by a nonwoven fabric coater schematically shown in FIG. 1²The coating liquid is applied. As the coating mechanism H, a die coater was used. As the drying means D, hot air was blown onto the non-woven fabric side to which the coating solution was not applied by using a single-sided air dryer having an effective length of 30cm, and then hot air was blown onto the non-woven fabric side to which the coating solution was applied by using two single-sided air dryers having an effective length of 30 cm. The drying temperature was 100 ℃. The coating speed was 30 m/min.

As the conveying roller T2 positioned between the coating mechanism H and the conveying roller immediately before the drying mechanism D, a roller having a diameter of 60mm and an aluminum alloy as a core material, which is covered with a concave-convex polyethylene sheet, was used. The concave-convex polyethylene sheets are adhered by spraying glue in a mode of not overlapping each other and not generating gaps.

As the conveying roller T3 immediately before the drying mechanism D and the conveying roller T4 inside the drying mechanism D, a roller having a diameter of 60mm and having an aluminum alloy core material covered with a water-repellent cloth was used. The water-repellent fabrics were fixed with a polyimide tape in such a manner that they did not overlap each other and no gap was generated.

As the water-repellent fabric for the conveying roller T3 and the conveying roller T4, JIS R3414: 2012 EP08B discloses a woven fabric in which a polytetrafluoroethylene resin is impregnated into a glass cloth to provide a water-repellent resin layer. Surface roughness Ra: 5 μm, contact angle of water is 110 deg.

[ example VI-2]

As the water-repellent fabric for the conveying roller T3 and the conveying roller T4, JIS R3414: 2012, a nonwoven fabric was coated in the same manner as in example VI-1 except that the glass cloth of EP06B was impregnated with a polytetrafluoroethylene resin to provide a woven fabric having a water-repellent resin layer. Surface roughness Ra: 3 μm, contact angle of water is 110 deg.

[ example VI-3]

As the water-repellent fabric for the conveying roller T3 and the conveying roller T4, JIS R3414: 2012, a nonwoven fabric was coated in the same manner as in example VI-1 except that the glass cloth of EP25 was impregnated with a polytetrafluoroethylene resin to provide a woven fabric having a water-repellent resin layer. Surface roughness Ra: 30 μm and a contact angle of water of 110 °.

In examples VI-1 to VI-2, no pinholes or coating unevenness due to permeation was observed, and a good coating surface was formed. In example VI-3, the uneven pattern of the water-repellent fabric was transferred, but pinholes and coating unevenness due to permeation were not observed. Further, even if the coating liquid is intentionally fixed to the conveying roller T3 and the conveying roller T4, the coating liquid can be easily wiped off with a wiper made of cloth wetted with water. This facilitates the cleaning and removal operation even when the coating liquid is fixed during coating. After the fixing and washing operation was performed 30 times, the nonwoven fabric was coated again in the same manner as described above, and a coated surface was formed which was as good as in the initial stage.

Comparative example VI-1

As the conveying roller T3 and the conveying roller T4, a polyimide tape was used to fix JIS R3414: 2012 to EP06B, a nonwoven fabric was coated in the same manner as in example VI-1. Surface roughness Ra: 3 μm, the contact angle of water cannot be determined.

Comparative example VI-2

A nonwoven fabric was coated in the same manner as in example VI-1, except that a polytetrafluoroethylene resin-coated roll was used as the conveying roll T3 and the conveying roll T4 instead of the roll coated with the water-repellent fabric. Surface roughness Ra: 1 μm, contact angle of water is 110 °.

In comparative examples VI-1 and VI-2, pinholes and coating unevenness due to bleeding were observed, and a good coating surface could not be formed. In comparative example VI-1, the coating liquid penetrated through the surface of the conveying roller was fixed to the conveying roller T4 in the drying mechanism D.

Industrial applicability

The coating of the nonwoven fabric using the nonwoven fabric coater of the present invention can be suitably used for producing products in which various coating liquids are applied to the nonwoven fabric, for example, for producing a separator for a lithium ion secondary battery in which inorganic particles are applied to the nonwoven fabric.

Reference numerals

1 surface shape after thermal spraying

2 Water repellent processed surface shape

3 convex part (before damage)

4 convex part (after damage)

1' surface shape after sandblasting

Surface shape after 2' water repellent plating

D drying mechanism

T1 conveying roller

T2 conveying roller

T3 conveying roller

T4 conveying roller

H coating mechanism

M non-woven fabric roll

W1 distance

W2 gap

h height

Period of alpha unevenness

Fine concavo-convex period of beta

Period A

a warp yarn

b weft yarns

c gap

d Water-repellent resin layer

Claims

1. A non-woven fabric coating machine is characterized in that in the non-woven fabric coating machine provided with a coating mechanism for applying a coating liquid to a non-woven fabric, a conveying mechanism for supporting and conveying the non-woven fabric applied with the coating liquid on a conveying roller and a drying mechanism for drying the applied coating liquid, the surface of the conveying roller is provided with a concavo-convex shape and water repellency.

2. The nonwoven fabric coater according to claim 1, wherein the transport roller is a roller whose surface is coated with a water-repellent concave-convex sheet.

3. The nonwoven fabric coater according to claim 1, wherein the transport roller is a roller having a surface made of polyolefin and a surface having a concavo-convex shape formed by machining.

4. The non-woven fabric coater according to claim 1, wherein the conveying roller is a roller having a surface with a concavo-convex shape formed by a processing method selected from the group consisting of cutting knurling, roll knurling, and laser engraving.

5. The non-woven fabric coater according to claim 4, wherein the feed roller is a metal roller.

6. A nonwoven fabric coater according to any one of claims 2 to 5, wherein the pitch of the irregularities is 300 to 1000 μm, the gap/pitch is 0.3 to 0.6, the height of the irregularities is 50 to 200 μm, and the contact angle of the surface is 85 ° or more.

7. The nonwoven fabric coater according to claim 1, wherein the feed roller is a roller subjected to thermal spraying water repellent processing.

8. The nonwoven fabric coater according to claim 1, wherein the feed roller is a roller subjected to sand blasting water repellent plating.

9. The non-woven fabric coater according to claim 1, wherein the feed roller is a roller covered with a water repellent fabric.