JP2009262064A - Curtain coater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of a curtain coater. <P>SOLUTION: The curtain coater comprises one or two or more downward dies 1A, 1B forming coating curtains by spraying a coating to the downward and a guide plate B receiving coating curtains sprayed through the downward dies 1A, 1B on a slanting surface Ba to be flowed down along the slanting surface and moving them as the coating curtains from the lower end of the downward curtain guide Bb onto the web w surface, wherein an upper ward die 1C spraying a coating toward the upper ward to be flowed down along the slanting surface Ba of the guide plate B is installed at the upper end of the guide plate B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a curtain coater.

  Coated paper such as printing paper, pressure-sensitive paper, and thermal paper used for catalogs and the like is produced by applying a paint onto a web (base material) that is a base paper by a coater and then drying. A machine for applying a paint in this way is called a coating machine. Conventionally, such a coating machine employs a post-metering method in which excessive paint is applied once on the web, and then scraped off with a blade or small-diameter rod or blown off with an air knife. Blade coaters, rod coaters, air knife coaters, etc. were the mainstream. However, in such post-metering coating, the paint penetrates the web a lot due to the hydraulic pressure when applying the paint to the web and the pressing force of the blade, etc., and maintenance due to wear of the blade and rod, etc. There are problems such as high costs.

  Therefore, in recent years, curtain coaters have been widely adopted in which a paint curtain film is ejected from a die (a chamber with a nozzle for producing a paint curtain film) onto a traveling web and applied onto the web. Curtain coaters have been used for a long time in fields such as photographic printing paper, but coating is stable due to air entrainment at high speed, bubbles mixed in paint, instability of paint curtain film due to insufficient mechanical accuracy, etc. Was not used in the paper industry.

  The present applicant has solved these problems, developed curtain coating technology as a stable technology, and has already supplied a large number of curtain coating machines to the whole world. Unlike conventional post metering type coating machines, curtain coating machines are easy to maintain because there are no consumables such as blades and rods, and the coating amount can be easily adjusted with high accuracy, and operability is good. There are features such as high effect of surface property improvement due to contour coating.

On the other hand, there is a multi-layer curtain coater using two or more dies. FIG. 5 is a partial cross-sectional view of a coating apparatus for a two-layer curtain coater of the invention disclosed in Patent Document 1.

JP 2006-247611 A

As shown in FIG. 5, the two-layer curtain coater according to the present invention includes two dies 1a and 1b for spraying paints ta and tb flowing through the slits da and db downward, respectively, and the two dies 1a. The paint curtains ca and cb sequentially ejected from 1b toward the slope Ba are sequentially stacked as the surface of the slope Ba is moved to form two paint layers. A guide plate B for transferring the paint layer from the downward curtain guide portion Bb onto the web w surface as two paint curtains ca and cb is provided. In this way, two coating layers sa (lower layer) and sb (upper layer) are formed on the running web w surface. In addition, the arrow is the advancing direction of the web w.

  By the way, the paint curtain films ca and cb fall free when they leave the dies 1a and 1b. However, the edge (edge) is pulled inward by the surface tension of the paint, and the width of the curtain films ca and cb becomes narrow. Will occur. An edge guide is provided to prevent such neck-in.

  FIG. 4 is a conceptual diagram of such an edge guide. In FIG. 4, 1 is a die, 2 is an edge guide, c is a curtain film of paint, and B is a guide plate. Since the edge guide 2 is made of metal and has hydrophilicity, it has an action of preventing neck-in. However, depending on the characteristics and flow rate of the paint, if the distance s from the die 1 to the guide plate B is inappropriate, the flow rate is small, and the paint curtain c is thin, the paint curtain c is as shown in the figure. It breaks in the width direction in the middle of free fall, resulting in a streaky flow.

In order to prevent such a phenomenon from occurring, the distance s from the die 1 to the guide plate B may be shortened to the distance s ₁ before it is broken in the width direction. If the upper paint layer r is disturbed, or if the distance s from the downstream second layer die 1b to the guide plate B in FIG. 5 is too short, the upstream first layer die 1a The paint layer ra on the formed guide plate B will be scratched. In general, the distance s from the die 1 to the guide plate B is preferably 5 mm or less. For this reason, the die 1 can be moved up and down to adjust its position.

  By the way, it is necessary to flow the coating material on the die 1 for ejecting the coating material before coating on the web. The paint spouted from the die 1 is received by the paint catch pan and circulated. If it doesn't flow in advance, it will take a considerable amount of time from the start of pouring paint to the die until the temperature and viscosity become constant and a stable curtain is obtained. End up.

  In this way, the die 1 can be moved and adjusted in the vertical direction in order to change the position of the die 1 from the state where the paint is received by the paint catch pan during the start-up preparation period to the position during normal operation. ing.

  Furthermore, the die 1 is preferably adjusted in profile in the width direction. FIG. 8 is a cross-sectional view of the die. In the figure, 1 is a die. Reference numeral 10 denotes a manifold that extends in the width direction of the die and into which the paint flows. The die 1 is assembled by joining a mold 10a having a manifold 10 and a mold 10b having no manifold 10 facing each other. Reference numeral 11 denotes a slit that communicates with the manifold and opens downward, and is formed between a fixed lip 10c and a movable lip 10d that are provided to face each other. The opening of the slit 11 is 0.3 to 0. .5 mm. The movable lip 10d is attached to the lower end of the mold 10b through a number of profile adjusting bolts.

  The profile adjustment bolt is a set of an upper push bolt 10e, a lower push bolt 10g, and an intermediate pull bolt 10f, which are attached at a pitch of about 50 mm in the die width direction. The paint curtain film profile is adjusted by fine adjustment in the width direction.

  The die 1 needs to adjust the spray width of the paint in accordance with the width of the web w to be coated. In order to change the opening width (spout width) of the slit 11, spacers are inserted into both ends of the slit 11 from below, and the spacer is pressed from the outside to prevent leakage and prevent the spacer from falling.

  By the way, Patent Document 2 discloses a slide die head type as a multi-layer curtain coater using two or more dies. FIG. 7 is a drawing of a slide die head type three-layer coating apparatus disclosed in the above document. In the figure, 20 is a slide die head, 20a is a slide surface, 21 is a metering pump, 22 is a manifold, 23 is a slit, t is a paint, w is a web, and c is a paint curtain.

JP-A-7-124510

  By the way, with respect to the multi-layer curtain coater shown in FIG. 5, the coating material is allowed to flow through the die before coating on the web, and each can be received and recirculated separately by the coating catch pan, or a profile adjusting device can be attached. On the other hand, there is a merit that all the dies require expensive moving devices in the vertical direction and the web traveling direction, and there is a demerit that the cost is increased.

  On the other hand, in the multi-layer curtain coater shown in FIG. 7, since all the dies are integrally formed, there is no need for a moving device for each, and there is a merit that it is less expensive. It is difficult to attach a profile adjusting device except for (die on the left side of FIG. 7). If the paint is poured into the die before coating on the web, the paint will be mixed. There is a big disadvantage that it cannot be reused even if it is received with a catch pan.

The present invention has been devised in view of such problems of the prior art, taking advantage of the merits of the multi-layer curtain coater shown in FIG. 5 and the multi-layer curtain coater shown in FIG. The object of the present invention is to provide a curtain coater that eliminates the disadvantages.

  In order to achieve the above object, the curtain coater of the present invention has one or two or more downward dies that form a paint curtain by jetting paint downward and a paint curtain jetted from the downward die on the slope. In the curtain coater having a guide plate that flows down along the slope and moves from the downward curtain guide at the lower end to the web surface as a paint curtain, the paint is directed upward at the upper end of the guide plate. An upward die that is ejected and flows down along the slope of the guide plate is disposed.

  Further, the position of the downward die can be adjusted in the height and the web traveling direction, and a pair of sliding edge guides whose lower surfaces are in contact with the upper surface of the guide plate are provided near both ends in the width direction of the guide plate. The pair of sliding edge guides are symmetrical to each other with respect to a vertical plane including the coater center line, and the dimension between the inner surfaces coincides with the paint ejection width from the downward die and the upward die. And the height changes along the slope of the guide plate, the upper surface is in contact with the lower end of the downward die, and the die is moved downward along the upper surface of the sliding edge guide. It is preferable to adjust the height of the paint curtain which is ejected from the die and reaches the guide plate.

  Furthermore, it is preferred that the paint jet width from the upward and downward dies and the dimension between the inner surfaces of the pair of sliding edge guides are adjustable.

The effects of the present invention are as follows.
The paint curtain spouted from one or two or more downward dies is received on the slope and flowed along the slope, and the upper end of the guide plate is moved from the downward curtain guide to the web surface as the paint curtain. In this configuration, an upward die that causes the coating material to be jetted toward and flows down along the slope of the guide plate is provided. Therefore,
(1) A profile adjusting device as shown in FIG. 8 can be provided for all downward and upward dies. This is superior to the slide die head type curtain coater shown in FIG.
(2) In order to allow paint to flow through each die before start-up at start-up, first, one or more downward dies above the guide plate are retracted downstream or upstream in the web traveling direction. The paint that has been moved is received by a paint catch pan disposed below it and used in a circulating manner. On the other hand, the paint flowing out from the upward die flows on the guide plate, flows down from the downward curtain guide, is received by the paint catch pan disposed below it, and is circulated for use. By circulating the paint in this way, it is possible to obtain a stable property value of the paint and to prevent plugging in the paint discharge slit. The downward-facing die moves from the state where the paint is received by the paint catch pan during the start-up preparation period or when the paper runs out to the upstream or downstream in the web traveling direction to the normal operating position. By moving to a certain extent, mixing of the paint during the movement of the die can be minimized. This point will be described in detail later with reference to the drawing (FIG. 6). In this respect, the present invention is superior to the slide die head type curtain coater shown in FIG. 7 in which the paint is mixed when the paint is poured before the application to the web.
(3) Since the upward die is fixed to the guide plate as described above, an expensive vertical and web moving device is not necessary for this die, and the cost is reduced.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 is a side view of a curtain forming portion of the curtain coater of the present invention, FIG. 2 is a cross-sectional view taken along arrow A in FIG. 1, and FIG. 3 is a cross-sectional view taken along arrow B in FIG. In these drawings, the same reference numerals are used for parts similar to those of the prior art described with reference to FIG. 4 or FIG.

In these drawings, 1A is an upstream downward die for ejecting paint downward to form a paint curtain, and 1B is a downstream downward die for ejecting paint downward to form a paint curtain. It is. These dies can be adjusted in height and position in the direction of web w travel. B is a guide plate that sequentially receives the paint curtains ejected from these dies on the slopes and flows down along the slopes so as to move from the downwardly directed curtain guide Bb to the web w surface as a paint curtain. c ₁ is the paint curtain from the upstream side of the down die 1A, c ₂ is the coating curtain from a downward die 1B downstream. r ₁ is a paint layer formed by the paint curtain c ₁ , and a paint layer r ₂ is a paint layer formed by the paint curtain c ₂ .

Reference numeral 1C denotes an upward die, which is fixed to the upper end of the guide plate B, jets the paint upward, and flows down along the slope Ba of the guide plate B. r ₀ is a paint layer formed by the upward die 1C. As shown in the figure, the paint layer r ₁ is formed on the paint layer r ₀ , and the paint layer r ₂ is formed thereon to form a three-layer paint layer, and the web is formed as a three-layer paint curtain from the curtain guide portion Bb. Move to w plane. The lip 30 (left lip) on the downstream side of the upward die 1C has the upper end flush with the upper surface Ba of the guide plate B, and the inner corner is chamfered so that the paint flows smoothly. It has become. The upper lip 31 (right lip) of the upward die 1 </ b> C is slightly higher at the upper end than the lip 30. 10 is a manifold, and 11 is a slit.

Reference numeral 2 denotes a pair of sliding edge guides whose lower surfaces are in contact with the upper surface of the guide plate B near both ends in the width direction of the guide plate B. The upper end of the slide type edge guide 2 covers the upward die 1C. The pair of sliding edge guides 2 are provided symmetrically to each other with respect to the vertical plane including the coater center line C, and the dimension between the inner faces coincides with the paint ejection width from the die. From a viewpoint of sliding the upper end of the edge guide 2 to point b on the downstream side is a constant height t _1, gradually height increases toward the downstream from the point b, the height t ₂ vertices c To. From the vertex c to the downstream, gradually height is low, leading to a point of height t ₃ d. Downstream from the point d remains constant height t _3.

  The position of the slide type edge guide 2 can be adjusted in the width direction. Reference numeral 3 denotes a position adjusting device, which is provided at two locations in the longitudinal direction of the slide type edge guide 2. The position adjusting device 3 includes a screw rod 4 rotatably attached to an outer side surface of the slide type edge guide 2, and a nut member 5 screwed to the screw rod 4 and fixed to an end surface of the guide plate B. .

  Although the paint spray width from the die is adjusted to match the dimension between the inner surfaces of the sliding edge guide 2, many methods have been disclosed. For example, in order to change the ejection width, spacers may be inserted at both ends of the slit of the die 1 and the spacers may be pressed from the outside to prevent leakage and prevent the spacers from jumping out.

In addition, there is a type in which a deck is inserted from the side and this deck is moved to adjust the ejection width from the slit 11. FIG. 9 is a perspective view of the ejection width adjusting device disclosed in Patent Document 3. As shown in FIG. In the figure, 1 is a die. Reference numeral 10 denotes a manifold that extends in the width direction of the die and into which the paint flows. A slit 11 communicates with the manifold and opens toward the tip. f is a deckle shaft, which is inserted into the manifold 10, and the tip end g is made of plastic and has a liquid-tight structure. The inside is hollow so that the paint flows. h is a deckle attached to the deckle shaft f, and the tip end portion i is made of plastic and has a liquid-tight structure, and is inserted into the slit 11. j is a paint.

JP-A-6-198240

Next, the function and effect of this embodiment will be described. (See Figure 1)
The paint curtain c ejected from the two downward dies 1A and 1B is received on the slope and flowed down along the slope Ba, and the lower end of the guide plate Bb is transferred to the web surface as the paint curtain from the downward curtain guide Bb. In this configuration, an upward die 1 </ b> C is provided that sprays paint upward and flows down along the slope of the guide plate. Therefore,
(1) A profile adjusting device as shown in FIG. 8 can be provided for all downward and upward dies. This is superior to the slide die head type curtain coater shown in FIG.
(2) FIG. 6 is a diagram showing the positions of the die and the catch pan from the start-up or out-of-paper state to the normal operation. In this figure, compared to FIG. A case where a total of three downward dies is used with the addition of the die 1D is described. FIG. 6 (A) is an explanatory diagram showing that the paint is allowed to flow through each die before coating at the time of start-up or when the paper runs out. The two downward dies 1A and 1B above the guide plate B are moved to the retracted position on the downstream side in the web traveling direction as indicated by the alternate long and short dash line, and the downward die 1D on the uppermost stream is upstream in the web traveling direction. The paint which has been moved to the retreat position on the side is received by the paint catch pans 40, 41 and 44 disposed below them and used in a circulating manner. On the other hand, as shown by the dotted line, the paint flowing out from the upward die 1C flows on the guide plate B, flows down from the downward curtain guide Bb, is received by the paint catch pan 42 disposed below, and is circulated for use. . Next, as shown in FIG. 6 (B), the downward-facing dies 1A and 1B are moved upstream in the web traveling direction from the state in which the paint is received by the paint catch pans 40 and 41 during the start-up preparation period or at the time of running out of paper. The paint catch pan 41 is placed in the same position, and the paint catch pan 40 is moved upstream in the meantime, toward the upstream end of the paint catch pan 40 toward the upstream. Since the guide plate 40a attached to extend obliquely upward covers the upper part of the paint catch pan 41, the paint flowing out from the downward die 1A can be circulated without being mixed with the paint flowing out from the downward die 1B. it can. On the other hand, when the uppermost downstream die 1D moves to the downstream side to reach the position during normal operation, the paint catch pan 44 is placed at the position as it is, but the downstream end of the paint catch pan 44 is placed downstream at the upper end. Since the guide plate 44a attached to extend obliquely upward toward the upper side covers the upper side of the upward die 1C, the paint flowing out from the downward die 1D can be circulated and used without contaminating the upward die 1C. On the other hand, the paint catch pan 42 disposed below the curtain guide Bb moves as indicated by an arrow in FIG. 6A, and the web travel direction during normal operation or when the mixed paint catch pan 43 is used. Move to the downstream retreat position. The mixed paint catch pan 43 moves as indicated by an arrow in FIG. 6A, and is positioned at the use position as shown in FIG. 6B to receive four types of paint. In this state, the paint is mixed and thrown away, but in this state, it may be a few seconds and therefore there is little loss. FIG. 6C shows a normal operation state. That is, the mixed paint catch pan 43 moves to the retracted position (shown on the downstream side in FIG. 6C, but may be on the upstream side as shown in FIG. 6A), and the mixed paint is It is applied to the web w. Incidentally, w ₁ indicated by the chain line in FIG. 6 (A) and FIG. 6 (B) is a passage of the web w in a state where no through web w. Further, when the paper runs out in the normal operation state shown in FIG. 6C, the state immediately shifts to the state shown in FIG. 6A. When the paper is recovered, the normal operation state shown in FIG. 6C is restored.
(3) Since the upward die 1C is fixed to the guide plate B, there is no need for an expensive vertical and web moving device for this die, and the cost is lower than that of the downward die alone. Become.

Returning again to FIG. A pair of sliding edge guides 2 are provided near both ends of the upper surface of the guide plate B in the width direction. By moving the dies 1A and 1B along the upper surface of the sliding edge guide 2, the dies 1A and 1B are moved. It is possible to easily adjust the heights of the paint curtains c ₁ and c ₂ that are ejected from the nozzles and reach the guide plate. Therefore, even if the flow rate is small and the thickness of the paint curtain is thin, the paint curtain will not break in the width direction in the middle of free fall and become a streaky flow (see FIG. 4). The paint layers r ₀ , r ₁ , r ₂ on the guide plate B are not disturbed, and the paint layer r ₀ on the guide plate is not scratched by the other dies 1A, 1B. A stable and uniform paint layer can be obtained.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention. For example, although it has been described that there are two or three downward dies, one or four or more dies may be used. Further, the guide plate B is described as being fixed, but the inclination angle of the slope Ba may be adjustable.

It is a side view of the curtain formation part of the curtain coater of this invention. It is A arrow sectional drawing of FIG. It is B arrow sectional drawing of FIG. It is a conceptual diagram of the conventional edge guide. It is a fragmentary sectional view of the coating device of the conventional 2 layer type curtain coater. It is explanatory drawing of pouring a coating material before coating to each die | dye. It is a side view of a three-layer coating apparatus of a slide die head type. It is sectional drawing of die | dye. It is a perspective view of an ejection width adjusting device.

Explanation of symbols

1A Upstream downward die 1B Downstream downward die 1C Upward die 2 Sliding edge guide B Guide plate w web w ₁ web passage

Claims (3)

  One or two or more downward dies that squirt paint downward to form a paint curtain and a paint curtain squirted from the downward die on the slope and flow down along the slope downward In a curtain coater having a guide plate that is moved from the curtain guide as a paint curtain onto the web surface, the paint is jetted upward on the upper end of the guide plate so as to flow down along the slope of the guide plate Curtain coater, characterized in that a die is arranged.   The downward-facing die can be adjusted in height and web moving direction, and a pair of sliding edge guides whose lower surfaces abut on the upper surface of the guide plate are provided near both ends in the width direction of the guide plate. The pair of sliding edge guides are symmetrical to each other with respect to a vertical plane including the coater center line, and the dimension between the inner surfaces is equal to the width of paint sprayed from the downward die and the upward die. The height is changing along the slope of the guide plate, the upper surface is in contact with the lower end of the downward die, and the die is moved along the upper surface of the sliding edge guide from the downward die. The curtain coater according to claim 1, wherein the height of the paint curtain which is ejected and reaches the guide plate is adjusted.   3. A curtain coater according to claim 2, wherein the width of the paint spray from the upward and downward dies and the dimension between the inner surfaces of the pair of sliding edge guides are adjustable.