JP2009028604A - Multi-layer coating die - Google Patents

Abstract

Provided is a multi-layer coating die which is a small and scaled simultaneous multi-layer slide hopper type coater while maintaining the coating amount distribution accuracy in the width direction.
A plurality of blocks 21 to 28 are connected to form a coating liquid slide surface 12a on an upper surface of the block, and a coating liquid flow path 40 is formed to a mating surface of the connected blocks. In the multi-layer coating die 12 in which a plurality of coating liquids discharged from the channel 40 are superimposed on the flow surface 12a and applied simultaneously to the web 16, the coating liquid flow path 40 supplies the coating liquid to the coating liquid flow path. The flow path width is continuously expanded in the web width direction from the mouth, the supply port, and the flow spreading slit that spreads to the coating width applied to the web 16, and the flow path width from the terminal end of the flow spreading slit to the flow lower surface 12a Is a uniform coating die, and has an interference slit that circulates to reach the flow surface 12a while maintaining the coating width.
[Selection] Figure 1

Description

  The present invention relates to a multilayer coating die, and is used in the production of films for photographic photosensitive materials, photographic paper, magnetic recording tapes, etc., and various coating compositions of various liquids to be coated on a continuously running belt-like support. The present invention relates to a slide hopper type multilayer coating die used as a coating device.

  Slide coating and sliding curtain coating are methods suitable for multilayer simultaneous coating, and the coating apparatus is configured to fasten several blocks together and form a pocket between adjacent blocks. The fastening accuracy of these blocks is related to the gap accuracy of each slot, and is an important requirement for determining the accuracy of the final coating film thickness.

  As such a coating apparatus, the following patent documents 1 and 2 describe a multilayer coating die in which a plurality of blocks are connected by a fastening member and multilayer coating is performed. FIG. 5 shows an example described in Patent Document 2 as such a conventional multilayer coating die. In the multilayer coating die 112 of FIG. 5, a pocket 121 and a coating liquid channel 140 are formed for each block 120 in order to push the coating liquid uniformly in the width direction. As shown in FIG. 5, the thickness of the block 120 is necessary to provide the block 120 with the pocket 121. The block 120 that constitutes the slide coater for simultaneous multi-layer coating of Patent Document 2 has a thickness of 30 mm or more. Moreover, the block thickness described in patent document 1 was using the block of 20-25 mm.

On the other hand, as a method for reducing the thickness of the coating head of the extrusion die, the following Patent Document 3 discloses a coating head that can form a uniform coating film over the entire coating width without providing a pocket. Are listed. FIG. 6 shows an example of a coating head described in Patent Document 3. FIG. 6A is a front view, and FIG. 6B is a perspective view. 6 extends continuously from the supply port 241 to the opening of the slit 240 in the width direction of the slit 240 and continuously reduces in the thickness direction of the slit 240 to apply the coating liquid. By supplying, a uniform coating film can be formed over the entire coating width.
JP 2001-70855 A JP 2003-117463 A JP-A 63-298044

  However, as described in Patent Documents 1 and 2, if the thickness of the block is increased, the entire coater becomes heavier and bulky, so the number of layers that can be applied simultaneously is limited, and a film with a desired number of layers can be obtained. There was a problem that it could not be formed at one time.

  Further, the block of Patent Document 3 has a complicated processing method and requires a long processing time. Further, when this block is used as a multilayer coating die, there is a problem that the block is continuously reduced in the thickness direction, so that the number of layers of the block increases, and the size and weight cannot be reduced.

  The present invention has been made in view of such circumstances, and provides a multilayer coating die that is reduced in size and weight of the simultaneous multilayer slide hopper type coater while maintaining the coating amount distribution accuracy in the width direction. Objective.

  According to a first aspect of the present invention, in order to achieve the above object, a plurality of blocks are connected to form a flow surface of the coating liquid on the upper surface of the block, and the flow surface is connected to a mating surface of the connected blocks. A plurality of coating liquid flow paths are formed, and a plurality of coating liquids discharged from the coating liquid flow paths are superposed on the flow surface, and the multi-layer coating is simultaneously applied to the web running the superposed coating liquid. In the die, the coating liquid flow path includes a supply port that supplies the coating liquid to the coating liquid flow path, and a flow path width that extends continuously from the supply port in the web width direction, and is supplied to the supply port. A spreading slit that spreads the applied coating liquid to a coating width that is applied to the web, and a channel width that is constant from the end of the spreading slit to the bottom surface, and the spread coating liquid is The flow down while maintaining the coating width Further comprising a, interference slit for flowing so as to extend to provide a multilayer coating die according to claim.

  According to the first aspect, the coating liquid flow path formed on the mating surface between the blocks of the multilayer coating die has a structure including an interference slit after the flow spreading slit. Accordingly, the coating liquid can be spread in the width direction by the flow spreading slit, and the coating amount of the coating liquid can be made uniform in the width direction by the interference slit. Therefore, it is possible to improve the application amount distribution accuracy in the width direction as compared with the case of only the flow spreading slit. Therefore, even if there is no conventional pocket, the amount of coating liquid in the width direction can be made uniform and applied with high accuracy. Further, since the block can be configured without a pocket, the thickness of the block can be reduced, and the entire multilayer coating die can be reduced in size and weight.

  A second aspect of the present invention is the method according to the first aspect, wherein the flow channel thickness of the flow spreading slit and the interference slit is constant from the supply port to the flow bottom surface at 1.5 mm or less, and the flow spreading of the interference slit. The length from the end of the slit to the flow surface is 40 mm or more.

  According to claim 2, since the coating liquid flow path is formed on the mating surfaces of the blocks, and the flow path thickness of the flow spreading slit and the interference slit is formed uniformly from the supply port to the flow bottom surface, Block processing and molding can be performed easily. In addition, by setting the length of the interference slit to 40 mm or more, when the coating liquid passes through the interference slit, the coating liquid supplied from the supply port is stabilized because the amount of the coating liquid is stabilized in the width direction. It can be uniformly applied in the width direction.

  A third aspect of the present invention is characterized in that, in the first or second aspect, the diameter of the supply port is formed in a tapered shape so as to be the same as the thickness of the spreading slit.

  According to the third aspect, since the diameter of the supply port and the thickness of the flow spreading slit are made equal, the coating solution supplied from the supply port can be easily supplied into the coating solution channel.

  A fourth aspect of the present invention is characterized in that in the first to third aspects, the thickness of the block is 1 mm or more and 10 mm or less.

  The fourth aspect defines the thickness of each block. According to the present invention, since it is possible to apply uniformly in the width direction without providing pockets, the block can be made thinner than the conventional block. By setting it as the said range, a coating device can be reduced in size and the number of layers which can be apply | coated at once can be increased.

  A fifth aspect of the present invention is characterized in that in the first to fourth aspects, the plurality of blocks are connected by a fastening member.

  According to the fifth aspect, a plurality of blocks are connected by a fastening member. Therefore, since the connecting surface of each block can be accurately maintained, each layer can be accurately maintained at a desired film thickness.

  A sixth aspect is characterized in that, in the fifth aspect, the fastening member is a bolt, and all of the plurality of blocks are connected by a single bolt.

  According to claim 6, all of the plurality of blocks are connected by one bolt. Therefore, the joint can be maintained with higher accuracy. In the present invention, since the block can be formed without providing a pocket, the thickness of the block can be reduced, and it is possible to connect with a single bolt. In addition, since the number of bolt heads and nuts can be reduced, the size and weight can be reduced.

  A seventh aspect according to the first to sixth aspects is characterized in that a length of the interference slit is 40 mm or more and 200 mm or less.

  The seventh aspect defines the length of the interference slit, and the interference slit is preferably within the above range. If the interference slit is short, sufficient pressure cannot be applied when applying the coating liquid, and a uniform coating film cannot be formed. Further, even if the length of the interference slit exceeds 200 mm, the effect of the uniformity of the coating film does not change and the apparatus becomes large, which is not preferable.

  According to the present invention, since the interference slit is provided after the flow spreading slit is provided in the block, after the coating liquid is spread in the block, the amount of the coating liquid is stably stabilized in the width direction by the interference slit. Can be made. Therefore, multilayer coating can be performed while maintaining the coating amount distribution accuracy in the width direction. Further, according to the present invention, since the block can be manufactured without providing a pocket, the thickness of the block can be reduced, and a multi-layer coating die that is reduced in size and weight can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a slide bead coating apparatus having a multilayer coating die according to the present invention. As shown in FIG. 1, the slide bead coating apparatus 10 includes a coating roll 11, a multilayer coating die 12 of the present invention, a die mount 13, and a decompression chamber 14 that also serves as a liquid receiver. A web 16 is wound around the coating roll 11 and conveyed, and a coating solution is applied to the conveyed web 16 from the slide surface (flow surface) 12a of the multilayer coating die 12.

  The multi-layer coating die 12 is configured by arranging a large number of blocks 21 to 28 in a vertical direction, arranging them in a horizontal direction, sandwiching them between a first block 19 and a final block 29, and fastening them with bolts 31. In the present embodiment, eight layers 21 to 28 are used to simultaneously apply eight layers. And in connection of each block 21-28, all the blocks are connected with the volt | bolt 31, and it connects using this volt | bolt 31 with two or more.

  The slide surface (flow surface) 12a is formed on the upper surfaces of the connected blocks 21 to 28. And the coating liquid flow path 40 from the supply port to the slide surface 12a is formed in the mating surface of the connected block. The coating liquid flow path 40 is formed outside one block, and the coating liquid flow path 40 can be formed by sandwiching this between the other blocks. Therefore, since it is not necessary to process the inside of the block, the block processing method becomes easy.

  The coating solution supplied from the supply port passes through the coating solution channel 40 formed on the mating surface between the blocks and reaches the slide surface 12a. In FIG. 1, eight layers can be applied simultaneously, and the eight types of coating liquid discharged from the coating liquid flow path 40 onto the slide surface are successively superimposed while flowing down the slide surface 12a. Is formed. In FIG. 1, the coating liquid discharged from the coating liquid flow path 40 formed by the block 21 and the first block 19 is the lowest layer. And as it goes to the upstream side of the slide surface 12a, it becomes the upper layer of the coating liquid, and the coating liquid discharged from the coating liquid flow path formed by the block 27 and the block 28 becomes the uppermost eighth layer. The multi-layered cloth liquid thus formed flows down to the tip of the slide surface 12a and is applied to the web 16 that runs from the tip of the slide surface 12a.

  FIG. 2 shows a partial side view and a sectional view of the first block 19 and the block 21 used in the multilayer coating die. 2A is a side view of the first block 19 and the block 21, and FIG. 2B is a cross-sectional view taken along the line A-A 'in FIG. As shown in FIG. 2A, the coating liquid channel 40 through which the coating liquid passes through the coating die is formed on the mating surface of the first block 19 and the block 21. 2A shows the example of the first block 19 and the block 21 as a representative example, the same applies to other blocks. The coating liquid channel 40 formed in the block 21 includes a supply port 41 that supplies the coating solution to the coating solution channel 40, and a channel width that is continuously expanded from the supply port 41 in the width direction of the web 16. A spreading slit 42 for spreading the coating solution supplied to the mouth 41 to the coating width applied to the web 16, and a flow path width W from the end of the spreading slit 42 to the flow lower surface 19a are formed to be constant. An interference slit 43 is provided for flowing the applied coating solution so as to reach the flow surface 19a while maintaining the coating width.

  The supply port 41 is preferably provided at the center of the block 21 in the width direction. By providing it in the center, the coating liquid supplied from the supply port 41 can be uniformly diffused.

  As shown in FIG. 2B, the coating liquid channel 40 formed in the block 21 extends in the width direction from the supply port 41 at a predetermined liquid supply angle θ. Then, after that, an interference slit 43 is provided, and the coating liquid spread in the width direction by the flow spreading slit 42 is maintained at a predetermined width. In this way, the coating liquid supplied from the supply port 41 is spread in the width direction of the web by the flow spreading slit 42, and then the coating liquid is made uniform by the interference slit 43. In the interference slit 43, a spacer 44 is provided on the side surface of the block 21 in order to maintain the coating solution uniformly in the width direction. The spacer 44 is preferably movable in the width direction of the block 21. By making the spacer 44 movable in the width direction, it is possible to deal with webs having various application widths.

  Moreover, it is preferable that each block 21-28 connects a some block with a single volt | bolt, as shown in FIG. And each block 21-28 is connected by passing the volt | bolt 31 through the fixing hole 45, as shown in FIG.2 (b). By connecting a plurality of blocks using a single bolt, there is no variation and coating can be performed with high accuracy. Further, the weight of the apparatus can be reduced.

  Next, the size of the coating liquid channel 40 formed in the block 21 will be described. The flow path thickness D of the flow spreading slit 42 and the interference slit 43 of the block 21 is preferably 1.5 mm or less and constant from the supply port 41 to the flow lower surface 21a. By setting the flow path thickness D within the above range, the coating liquid can be uniformly diffused in the width direction of the block 21. In addition, since the block thickness per layer can be reduced, more blocks can be stacked. When the channel thickness D exceeds 1.5 mm, the flow in the coating solution channel extends in multiple directions, so that the uniformity of the coating solution cannot be maintained.

  Moreover, it is preferable that the length from the termination | terminus of the flow spreading slit 42 of the interference slit 43 to the flow surface 21a is 40 mm or more. By making the length of the interference slit 43 sufficiently long, it is possible to take a long time to hold the coating liquid in the interference slit 43, so that the coating can be performed stably. If the length of the interference slit 43 is 40 mm or more, coating can be performed stably, but it is preferably 60 mm or more. In addition, the upper limit is preferably 200 mm or less, and more preferably 150 mm or less, from the viewpoint of reducing the size and weight of the coating die. The channel thickness D is preferably 1.5 mm or less, and more preferably 1.0 mm or less. This is because each of the blocks 21 to 28 used in the multilayer coating die 12 of the present invention can be applied uniformly in the width direction, and is particularly effective for the blocks in the above range.

  In the above embodiment, the multilayer coating die 12 used in the slide bead coating apparatus has been described. However, the coating die of the present invention is not limited to the slide curtain method, the extrusion bead method, the extrusion curtain method, and the like. It may be used for the coating method.

<Test Example 1: Confirmation of application amount distribution in width direction>
[Used liquid conditions]
A commercially available surfactant (Lapisol A90 (Nippon Yushi Co., Ltd.)) and a thickener (sodium polystyrene sulfonate (Fujifilm Fine Chemicals Co., Ltd.)) were added to a 5% gelatin aqueous solution, and the viscosity was 50 mPa · sec. The liquid properties were adjusted so that the static surface tension was 30 mN / m.

[Experimental method and evaluation method]
Using the slide bead coating apparatus shown in FIG. 1, the distribution of the coating amount in the width direction was measured. A block having a thickness of 3 mm was used, and the application amount distribution was measured by changing the liquid supply amount using the liquid supply angle, the slit clearance (CL) and the interference slit length as the apparatus parameters and the application operation conditions. The test parameters are shown in FIG.

The measurement was performed by sampling the amount of liquid at a fixed time at five points in the slide surface width direction and measuring the weight. Evaluation was performed according to the following criteria.
○: A sufficiently satisfactory coating amount distribution was shown.
Δ: An almost satisfactory coating amount distribution was shown.
X: An unsatisfactory coating amount distribution was shown.

[result]
The results are shown in FIG. When the slit clearance (CL) was 0.5 mm, the liquid supply angle was 66 °, and the interference slit length was 60 mm, a good coating amount distribution was obtained within the range of the liquid feeding amount examined. By shortening the interference slit length, an almost satisfactory coating amount distribution was obtained at 40 mm, but when it was shortened to 20 mm, a satisfactory coating amount distribution was not obtained in all flow ranges.

  In addition, when the slit clearance was 1 mm, the liquid supply angle was 66 °, and the interference slit length was 60 mm, an almost satisfactory coating amount distribution was obtained. However, when the slit clearance was 3.0 mm under the same conditions, The coating amount distribution deteriorated.

  From the above, it can be confirmed that a nearly satisfactory coating amount distribution can be obtained by setting the slit clearance to 1 mm or less and the interference slit length to 40 mm or more, regardless of the liquid supply angle and the amount of coating liquid fed. It was.

<Test Example 2: Confirmation of coated surface state with ultra-thin layer coater>
[Used liquid conditions]
A commercially available surfactant (Lapisol A90 (Nippon Yushi Co., Ltd.)) and a thickener (sodium polystyrene sulfonate (Fujifilm Fine Chemicals Co., Ltd.)) were added to a 5% gelatin aqueous solution, and the viscosity was 50 mPa · sec. The liquid properties were adjusted so that the static surface tension was 30 mN / m.

[Experimental method and evaluation method]
The test was conducted using a multi-layer coating die capable of performing simultaneous multi-layer coating having a three-layer structure on the slide bead coating apparatus shown in FIG. The coating die is the front and back of a plurality of ultra-thin layer blocks having a block thickness of 3 mm, a liquid supply angle of 66 °, a slit clearance of 0.5 mm, and an interference slit length of 60 mm in which the effect in the width direction coating amount distribution is recognized in Test Example 1. A die processed by sandwiching a 20 mm thick block was used. As a method of incorporating this die into the coating apparatus, as shown in FIG. 1, all the blocks were skewered and fixed on the bolt. Then, using this ultra-thin layer coater, simultaneous multi-layer coating with a three-layer structure was performed, and the coating surface state at that time was confirmed. In the test, the coating amount of the first layer and the third layer was fixed, the coating amount of the second layer was changed, and the surface state of the entire three layers was visually evaluated. As Comparative Example 6, a test was performed using a conventional coating coater (described in FIG. 5). Evaluation was performed according to the following criteria.

○: The coated surface shape is equal to or better than the coating using a conventional coating coater.
Δ: The coated surface is slightly inferior to a conventional coating coater.
X: The coated surface is inferior to the conventional coating coater.

[result]
The results are shown in FIG. As shown in FIG. 4, regardless of the amount of the coating solution for the second layer, the film surface of the three layers was good, and a coated surface shape having no problem as compared with the conventional case could be obtained.

  As described above, an interference slit is provided after the spreading slit, the clearance is the same, 1 mm or less, and the interference slit is 40 mm or more, so that the block can be thinned and coating is performed while maintaining coating accuracy. The die can be reduced in size and weight. In addition, it became possible to manufacture a super multi-layer slide coater by sandwiching the thinned block between the first block and the final block, which were thickened, and sandwiching all the blocks with one bolt. .

It is the schematic of a slide bead coating device provided with the die for multilayer coating of the present invention. It is the (a) side view and (b) A-A 'sectional view of the block used for the multilayer application die. 6 is a table showing the results of Test Example 1. FIG. 10 is a table showing the results of Test Example 2. FIG. It is the schematic of a coating device provided with the conventional die for multilayer coating. The block (a) front view and (b) perspective view of the block used for the conventional application | coating are shown.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Slide bead coating device, 12 ... Multi-layer coating die, 12a, 19a, 21a ... Slide surface, 13 ... Die mount, 14 ... Decompression chamber, 16 ... Web, 19 ... First block, 21-28 ... Block, 29 ... last block, 31 ... bolt, 40 ... coating liquid flow path, 41 ... supply port, 42 ... spreading slit, 43 ... interference slit, 44 ... spacer

Claims (7)

A plurality of blocks are connected to form a flow surface of the coating liquid on the upper surface of the block, and a flow path of the coating liquid reaching the flow surface is formed on the mating surface of the connected blocks. In a multi-layer coating die that simultaneously superimposes a plurality of coating liquids discharged from the flow surface, and simultaneously coats the superimposed coating liquid on a traveling web,
The coating liquid channel is
A supply port for supplying the coating liquid to the coating liquid channel;
A flow spreading width is continuously expanded from the supply port in the web width direction, and a spreading slit for spreading the coating liquid supplied to the supply port to a coating width applied to the web;
An interference slit that has a constant flow path width from the end of the flow spreading slit to the flow lower surface, and allows the spread coating liquid to flow to the flow lower surface while maintaining the coating width. A multilayer coating die characterized by that.   The flow channel thickness of the flow spreading slit and the interference slit is formed to be constant at 1.5 mm or less from the supply port to the flow lower surface, and from the terminal end of the flow expansion slit to the flow lower surface of the interference slit. 2. The multilayer coating die according to claim 1, wherein the length is 40 mm or more.   3. The multilayer coating die according to claim 1, wherein the supply port has a tapered shape so that a diameter of the supply port is the same as a thickness of the spreading slit.   The multilayer coating die according to any one of claims 1 to 3, wherein the block has a thickness of 1 mm or more and 10 mm or less.   The multilayer coating die according to any one of claims 1 to 4, wherein a plurality of the blocks are connected by a fastening member.   6. The multilayer coating die according to claim 5, wherein the fastening member is a bolt, and all of the plurality of blocks are connected by a single bolt.   The multi-layer coating die according to any one of claims 1 to 6, wherein a length from an end of the spreading slit of the interference slit to the flow surface is 40 mm or more and 200 mm or less.

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