EP1598115A2 - Curtain coating apparatus - Google Patents

Abstract

Curtain coater has caper head (3) with slot (s2) at edge which is broadly framed than the other part of slot (s1). The widened slot is arranged in a distance from the edge side of the caper head. Broader slot has different shape such as rectangle, circle or oval. The caper head is built up from two caper bodies (3b). The broader part of the slot has a width dimension double of the other slot. The slots are provided at the caper head for track spacing purpose.

Description

The invention relates to a curtain coating with a coating head the one coating color from a slot provided on the coating head from above to a running under it, especially from paper or cardboard, falls and forms a coating curtain, which on a Side of the aforementioned train arrives.

Coated papers such as for catalogs, brochures, Thermal paper or automatically canceled tickets are by applying a coating color to the surface of a raw paper existing railway produced.

Machines for applying these coating colors are generally referred to as Whiskers, with such a coating, by a Position above the example of paper or cardboard existing Apply the coating paint on this web as a curtain coating (Curtain Coater).

As shown in Fig. 6 (a), coating paint of a predetermined thickness is applied to the The top of the train is applied in the head body 101 [head body] coating paint from the curtain coating unit 100 from above in with respect to the conveyed web (not shown) so delivered that it forms perpendicular to the plane of the paper in Fig. 6 (a) a curtain tc.

This curtain coating 100 generally occurs in the case of Curtains tc with a low flow rate (from 6 to 7 l / min / m width and less) the problem that, as shown in Fig. 6 (b), due to inward acting surface tension the edge areas ce of Curtain tc be pulled inside, causing the curtain tc the Coating color t becomes unstable.

To solve this problem, in the case of the curtain coating shown in FIG 200 at the two ends of the (not shown) slot, the the dispensing opening for the coating color in the coating head body 201 (head body), guide rods gb or plates provided. With help of these devices is the curtain formed by the coating color t tc guided and the destabilization of the curtain tc avoided.

As a publicly available document in which one refers to the The present application is described in the present application is the Japanese Laid-Open Patent Publication JP-A 8-1061 is known.

As mentioned above, curtain coating works 100 in such cases, where the flow rate of the delivered Coating color t is low, in general the problem that the Edge areas ce of the curtain tc are drawn inward, resulting in destabilization of the curtain tc of the coating color t.

At even lower coating color flow rates, the curtain will then become tc uneven and turns into a rain. In this case, the Maintaining the specified strike performance significantly difficult.

The coating color t must always flow at a certain minimum flow rate, so that this defect can be remedied. This results in the Disadvantage that actually unnecessary coating color t is consumed.

In long-term operation, it comes with the guide rods gb or - In addition, Curtain Brush 200, which is provided with panels, also causes Coating color t adheres to the guide rods gb or plates and himself solidified there after drying. This causes the curtain tc in Clutter and leadership functionality is lost.

At the beginning of the coating application, there are also disturbances between the guide rods gb or plates on the one hand and the (not shown) paint tray in which the coating color is collected. Also As a result, the curtain tc of the coating color t disadvantageously Disarray.

The use of guide rods gb or plates also have the Disadvantage that they are similar in the execution of maintenance or similar. to disturb. They thus lead to a decline in labor productivity.

Given this situation, it is an object of the invention, a To provide curtain coating, which at a low Coating color flow rate with simple means the stabilization of the coating color curtain enables and shows good order performance.

According to the invention according to claim 1, this object is achieved by that the slot also at least one next to the web surface, or forms outside the width of the web falling curtain part, wherein the Slot in the area outside the web surface or the web width at least partially wider than the slot that forms the rest or gives actual curtain on the web surface.

As a result, the flow rate of the coating curtain, which rises from the wider slot next to the web surface is delivered to. hereby becomes the influence of the inside of the curtain Coating color surface tension decreases and prevents the Curtain over the rail surface gets in disorder.

There are thus stable coating color curtains at low flow rates receive. The invention thus allows for a reduced Coating color flow rate good coating performance.

In an embodiment of the invention, it is provided that the slot on Coating head is designed so that at least one of its two marginal ends is shaped wider than the remaining part of the slot. This allows to reduce the width of the curtain coating.

An expedient embodiment of the novel curtain coating unit is that the wider part of the slot Width dimension, which is at least twice the width dimension the remaining slot responsible for hitting the track, is.

The flow rate of the coating color therefore exceeds a certain one here necessary degree, so that the force acting in Vorhangsgabgabichtung direction increases and an even more stable coating color curtain is obtained.

According to the invention it is provided that the at least one wider Slot at the edge end the shape of a rectangle, circle, oval or the like.

It is very advantageous if the coating head consists of two bodies is, with the broadened slot only in one body, or in both Body is incorporated. The coating head is thus easier to produce.

The curtain coating can be further developed by the widened slot at a certain distance from at least one edge end of the coating head or its body is arranged. He therefore does not need to be at the very end, but instead can also be positioned at other locations outside the web width.

Preferred embodiments of the invention:

In the following the invention is based on embodiments below Referring to the drawings:

Show it:

Figs. 1 (a) and (b) show the concept of the operation of the curtain coating machine according to the embodiment 1, wherein Fig. 1 (b) is in the direction of the arrow A in Fig. 1 (a).

Figures 2 (a), (b) and (c) show cross-sections along the lines CC and BB, respectively, of the coating head in Figure 1 (b) and the underside of the curtain coating system shown in Figure 1, respectively.

Figures 3 (a), (b), (c) and (d) illustrate the operation of the curtain coating unit of Embodiment 2 of the invention, wherein Figure (b) shows the underside of the coating head in Figure (a), Figs. (c) show a cross section along the straight line DD in Fig. (a) and Fig. d show a cross section along the straight line EE in Fig. (a).

4 (a) and (b) show a first and a second variation of the curtain coating unit of Embodiment 2.

Figs. 5 (a), (b) and (c) show the underside of the coating heads in Embodiments 1 and 2 with variations in the shape of the widened slots.

Figures 6 (a) and (b) illustrate the operation of a conventional curtain coating and the operation of the curtain coating shown in Figure 6 (a) in a low-flow-rate (prior art) paint application.

Fig. 7 shows the operation of a conventional curtain coating with guide plates (prior art).

Embodiment 1

In the curtain coating 1 of this first embodiment For example, as shown in Fig. 1 (a), it is a device based on the Surface of a base paper web 2 a coating color t applies, wherein the Lane 2 at a speed of 100 to 2000 m / min in the α marked arrow direction is promoted.

Fig. 1 (b) is a view of the device shown in Fig. 1 (a) Direction of the arrow A. The curtain brush 1 gives a coating color t starting from a coating ink feed tk the closer below discussed chamber of a coating head 3 is supplied via a Slit s1 and the wider slots s2 in the form of a curtain tc on the Top of the conveyed web 2. Here are Coating color curtain part (inner part) tc1 and tc2 as edge-side Curtain part gebi Idet. As a result, on the top of the web 2 a Coating color layer in a predetermined thickness of, for example, 10 formed to 50 microns.

The particular feature of this curtain coating 1 is that the thickness m _c1 for the inner part of the coating color curtain tc1 above the top of the web 2 0.3 mm are specified, while the thickness m _{c2 of} the edge coating curtain parts tc2, which forms part of Show coating paint curtain next to the top of the web 2, 1 to 3 mm are given. As a result, higher flow rates are achieved in the coating color curtain parts tc2 at the two side edges than in the inner part of the coating color curtain tc1. As a result of the associated increase in weight, a resistance to the surface tension acting with orientation inwards on the marginal coating color curtain parts tc2 is built up and thus a stabilization of the coating color curtain tc is achieved.

This feature makes it possible for the curtain coater 1 to have a specified order performance with a specific coating color quantity t at low flow rate.

As shown in Fig. 1, so that forms from the on the coating head. 3 slits s1 and s2 provided coating color t the Coating color curtains tc1 and tc2 and then in a predetermined thickness applied to the top of the web 2. At the same time, as in Fig. 1 (b) shown, the next to the top of the web 2 issued and therefore not on the web applied excess coating color t in the paint tray kp caught.

The collected coating color t is in a tank, not shown returned and together with newly supplied coating color t with a predetermined pressure by means of a pump circulated. To Defoaming, filtration and the like, they will then over the Coating ink supply inlet tk of the chamber 3c (see Fig. 2 (a), which has a Cross section along the line B-B in Fig. 1 (b) shows) of the coating head 3 supplied.

The coating color t fed into the chamber 3c becomes the coating equipment the top of the web 2 through the slots s1, s2 in the form of curtains tc1, tc2 are delivered to the top of the web 2.

The brush head, as shown in FIG. 1 (b), has a body 3b, two-sided seals 3p, which seal the body 3b and thus a Prevent leakage of coating color t, and double-sided coating end plates 3e, which the seals 3p closely following the Keep body 3b.

As shown in FIG. 2 (c) showing the underside of the coating head shown in FIG. 1 (b), a slit s1 is provided on this coating head 3. The slit s1 serves to form the inner coating color curtain tc1 and is provided on the coating head body 3b1, 3b2 with a width dimension m _s1 of 0.3 mm, the slits s2 are again provided with a width m _s21 of 1 to 3 mm at the seals 3p and serve to form the two marginal coating color curtain parts tc2.

Here, a width m _s1 = 0.3 mm for slit s1 and a width m _s21 of at least 0.6 mm for slit s2 is preferred. In particular values of 1 to 3 mm have proven to be ideal.

As a result of this different choice of the width dimensions m _s1 and m _s21 for slit s1 and slit s2, a higher flow rate is achieved in the edge-side coating color curtain parts tc2 than in the inner portion of the coating color curtain tc1.

In this embodiment, by way of example, 0.3 mm was selected as the width dimension m _s1 of slot s1, but it is possible to specify values of 0.2 to 0.5 mm as the width dimension m _s1 instead. Thus, the width dimensions m _s1 and m _s21 for slit s1 and slit s2, respectively, can be suitably selected according to the coating conditions, such as the thickness of the coating _color layer to be applied to the web 2.

The swab body 3b has, as shown in Figs. 2 (a) and 2 (c) first brush body 3b1 and a second brush body 3b2, the Together form the body 3 and 3 strokes, and a first lip 311 and a second lip 312, in the first and second Streichkopfkörper 3b1, 3b2 are included and to adjust the Width of slot s1 serve.

The first and second coating head bodies 3b1, 3b2 are made, for example each made of stainless steel, as shown in Fig. 1 (b) and Fig. 2 (c) shown, cutouts on which the chamber 3c with defined geometry and one side portion of the slot s1 each having the specified width of 0.3 mm, and are made in an elongated shape, so that they correspond to the width of the web 2 from 1 to 10 m or wider.

The lips 311, 312 are made of stainless steel, for example. In they are drilled through a hole that is part of the 0.3 mm wide Slit s1 forms, as shown in Fig. 2 (a), by the one (not shown) Screw for adjusting and adjusting the width of the slot s1 out becomes.

The gaskets 3p are shown in FIG. 2 (b), a cross section along the straight line CC in FIG. 1 (b). These are, for example, components made of rubber or rubber, for example butadiene rubber. As shown in Fig. 2 (c), a slot s2 formed therein is formed by a slit s21 having a width dimension m _s21 of 1 to 3 mm around the slit s1 of the swab bodies 3b1 and 3b2 and a slit s22 which along the slit s1, the swab body 3b1 and 3b2 is provided and has the same width dimension m _s22 = 0.3 mm. At the same time, a hole 3p1 corresponding to the chamber 3c in the coating head body 3b is formed in the gaskets.

Thus, since the width dimension m _{s21 of} the slit s21 in slit s2 is larger than the width dimension m _s1 (= 0.3 mm) of slit s1 in slit s2, a larger cross-sectional area is formed than in slit s1, therefore the coating color t passes through Slot s2 flows at a higher flow rate than through slot s1. Accordingly, the coating color curtain tc2, tc2 discharged from slit s2 is thicker than the coating color curtain tc1 discharged from slit s1.

In this example, as shown in Fig. 2 (b), the wider portion s21 the slit s2 provided in the gasket 3p from the slit opening s2k ago over part of the total length of the slot s2 inwards However, it can also over the total length of the slot s2 be formed when it from the slot opening inwards is formed.

Thus, as shown in Figs. 1 (b) and 2 (c), the slots s2 have the a portion of the coating color curtain next to the top of the web. 2 forming slits and the edge sections tc2, tc2 of Coating color curtain form, a wider width than the slot s1, the the inner portion tc1 of the coating color curtain and thus the above the upper side of the web 2 lying part of the coating color curtain forms. This causes an increase in the flow rate of the marginal Coating curtain parts tc2 causes and due to it accompanying weight increase will be the influence of the inside directed surface tension on the edge side Paint curtain parts tc2 diminished and thus prevents the edge coating color curtain parts tc2 are drawn inwards.

This prevents rest of the coating curtain, thereby a stabilization of the coating color curtain is achieved and a stabilized application or a coating of the web in high quality is possible.

Due to the increase in the flow rate in the marginal Coating color curtain parts tc2, since this increase to a Stabilization of the curtain leads to a reduction of the Total flow rate tc1 in the coating curtain possible.

For example, if a flow rate of 7.4 l / min / m was previously required to achieve a given coating performance, as has been verified by adjusting the slot s1, (which defines the inside coating color curtain tc1 above the top of the web 2) and the width of the web corresponds to 2), to a width m _s1 of 0.3 mm and adjusting the slits s2, which form the edge coating color curtain tc2 next to the top of the web 2 (ie outside the web width), to a width m _s21 of 3 mm, a reduction of the coating color flow rate to 5.4 l / min / m can be achieved.

By increasing the flow rate of the edge coating color curtains tc2 becomes, as the contraction of the coating curtain inside is correspondingly low, the coating color curtain at the smallest Width dimensions stabilized. Therefore, it is now possible that Curtain brush with the smallest possible overall width perform.

The invention thus enables a curtain coating, which at high Coating achieves a stable coating color curtain and with low coating color flow rates works.

Therefore, the fields of application of curtain-brushing expanded and universal application areas for curtain coating be opened.

Embodiment 2:

In the case of the curtain coating 21 of the invention Embodiment 2, as in FIGS. 3 (a) and 3 (b), becomes one enlarged view of the underside of the coating head 23 in Fig. 3 (a), shown on the formation of slots in the seals 23p, 23p omitted, instead are exclusively in the prank head body 23b a Slot 2s1 and wider slots 2s2 provided.

In this embodiment of the invention is over the top of the Web 22 by dispensing coating color t by the in the coating head body 23b slit 2s1 provided an in-line coating curtain 2tc1 formed, the edge coating color curtains 2tc2, 2tc2 with high Flow rate adjacent to the top of the web 22 are partially through Dispensing of coating color t formed by the slots 2s2, 2s2. hereby Stabilization of the coating color curtains 2tc1 and 2tc2 is achieved and the achievement of predetermined strike performance ensured.

In this curtain coating machine 21, as shown in Fig. 3 (a) and Fig. 3 (c), a cross section taken along the line DD of the coating head 23 in Fig. 3 (a), a chamber is formed to form the inside coating paint curtain 2tc1 23c for supplying the first coating body 23b1 and the second coating body 23b2 with coating color t and a slit 2s1 which adjoins the chamber 23c and has a width dimension m _s1 .

On the first and second coating body 23b1, 23b2 are each a first and second lips 2311, 2312 are provided, of which at least one or both kept adjustable by a setting screw become. At the first lip 2311 and the second lip 2312 is the Slit 2s1 formed so that to him the first coating head body 23b1 and the second brush body 23b2.

As shown in Fig. 3 (a), as also in Fig. 3 (d), a cross section along the straight line EE of the coating head 23 in Fig. 3 (a) is to form the edge coating paint curtain portions 2tc2 adjacent to the upper surface the web 22 are formed at a high flow rate, at the first and second swab bodies 23b1, 23b2 adjacent to the chamber 23c and parallel to slit 2s1, there is provided a slit 2s22 having a width dimension m _s22 which is identical to width dimension m _s1 .

At the coating head bodies 23b1 and 23b2, a first and a second lip 2311 and 2312 are provided, which are held adjustable by means of adjusting screws. At these lips, the slit 2s22 is formed so as to be connected to the first swab body 23b1 and the second swab body 23b2. Below this, a slit 2s21 is provided which widens toward the first lip 2311 and has a width dimension m _s21 which is larger than the width of slit 2s22.

When the width dimension m _s1 of slit 2s1, over which the inside-side coating curtain part 2tc1 is formed, is 0.3 mm, as the width dimension m _s2 for the slits 2s2 through which the edge-side coating color curtain parts 2tc2 are formed, at least 0.6 mm must be selected, however, it is preferably selected in a range of 1 to 3 mm.

By the features of Embodiment 2, the same Achieved advantages as described in Example 1.

In the following two variations of embodiment 2 are under Referring to Fig. 4 explained.

In Embodiment 2, as shown in FIG. 3 (b), in FIG Extension of the slots 2s2, which are the marginal Coating color curtain parts 2tc2 form, only an extension on the first Coating head body 23b1 made. In the case of the coating head 23 'of However, in variation 1, the slots 2s2 'are instead provided such that As shown in Fig. 4 (a), a drawing of the bottom, their ends are shown each by the same measure m3 in the first and second Expand the brush body 23b1 ', 23b2' into it.

In Variation 1, the slots 2s2 'are also symmetrical to the plane, in the first coating body 23b1 'to the second coating head body 23b2 connects, arranged. The slots can, however, also to each other be arranged asymmetrically.

When coating head 23 "in Variation 2, as shown in Fig. 4 (b), a view of the underside of this variation, the slots 2s2 ', which form the thicker coating color curtain, each m at a distance ₄ to the ends of the first and second Coating body 23b1 ", 23b2" provided.

The wider slots 2s2 "so do not necessarily on the two be formed outermost ends of the coating color curtain, but can also be provided widened in other places.

The widened slots can thus be positioned at the coating head be that their position outside the top of the web 2 and destabilization of the curtain is avoided (see FIG. 1 (b), Fig. 3 (a)). The position of the widened slots is thus by no means limited to a particular position.

In the above embodiments 1 and 2, the broadening of the Slots on both sides outside the top of the track However, some effect is already achieved when the Widening only on one side outside the top of the track is made.

The material in which the widened slots are provided can can be chosen arbitrarily, for example, they can widened slots provided on both the first and second coaters In addition, they can, as in Example 1, in the Coating body seal or even be provided so that they connect both to the brush head body and its gasket.

As a cross section of the widened slots was in the Embodiments 1 and 2, a four-sided cross-section shown in However, as shown in FIG. 3 (b), the cross section of slit 2s2 may also be as shown in FIG 5 (a), are made round, and that shown in FIG. 4 (a) Cross-section of slot 2s2 'may also be round, as shown in Fig. 5 (b) be executed. In the same way, also in Fig. 4 (b) shown Slot 2s2 ", as shown in Fig. 5 (c), performed round.

The cross-section of the widened slots s2, 2s2, etc., except the in the embodiments illustrated four-edged or round shape Another form, such as an ellipse or an oval or a take another form, as long as it is ensured that the slot a Width at which the thickness of the curtain formed at least twice the thickness of the inner slot part s1, 2s1, etc. formed Curtain is.

Application examples of the invention are brush strokes of cardboard and papers for calendars, catalogs, brochures, thermal paper or pressure-sensitive paper, and brushes for one-sided brushing of automatically validated tickets with a magnetic Coating color. As long as it concerns Schreichwerke, which on tracks apply a coating color are the applications of the Invention no limits.

reference numeral

1, 21, 100, 200

Curtain coater

2.22

train

3, 23, 23 ', 23 "

String head

s1, 2s1, 2s1 ', 2s1 ", s21, s22, 2s21, 2s22

slot

s2, 2s2, 2s2 ', 2s2 "

Slotted or widened slot

tc

Coating color curtain

tc1, 2tc1

Upper edge of coated coating curtain

tc2, 2tc2

shaped next to the track top Coating curtain with larger curtain thickness

t

coating color

3b, 23b, 3b1, 23b1, 23b1 ', 23b1 ", 3b2, 23b2, 23b2 ', 23b2 ", 101, 201

String head body

3p, 23p, 23p, 23p "

poetry

2311.311

String head lips

2312.312

String head lips

3e, 23e, 23e ', 23e "

endplate

m _c1 , m _c2

slot width

m _s , m _s1 , m _s2 , m _s21 , m _s22

slot width

m ₃ , m ₄

distance

ce

border area

gb

guide rod

α

arrow

3c, 23c

chamber

tk

Coating color supply inlet

3p1

hole

s2k

slot opening

Claims (6)

Curtain coating unit (1) with a coating head (3) from which a coating color (t) from a slot (s1) provided on the coating head (3) falls from above onto a web (2), in particular from paper or cardboard, running underneath, and a curtain color curtain (tc), which on one side of the aforementioned path (2) passes, characterized in that the slot also forms at least one next to the web surface or outside the width of the web a falling curtain part, wherein the slot in the area is formed at least partially wider outside the web surface or the web width than the slot which emits the curtain on the web surface. Curtain brushing according to claim 1, characterized in that the slot is formed on the coating head so that at least one of its edge-side ends (s2) is formed wider than the remaining part (s1) of the slot. Curtain coating system according to claim 1 or 2, characterized in that the wider part of the slot (s2) has a width dimension which is at least twice the width dimension of the remaining slots (s1). Curtain brushing according to claim 1 to 3, characterized in that the wider slot (s2) has the shape of a rectangle, circle, oval or the like. Curtain brushing according to claim 1 to 4, characterized in that the coating head (3) consists of two bodies (3b1, 3b2, 23b1, 23b2) is constructed, wherein the widened slot (s2) is incorporated only in one body or in both bodies , Curtain brushing according to claim 1 to 5, characterized in that the widened slot (s2) at a distance (m ₄ ) from the edge end of the coating head (3) or the or the body is arranged.

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