JPH0226678A - Method and apparatus for applying foamable melt or foamable liquid - Google Patents

Abstract

PURPOSE:To keep a foaming characteristic by ejecting a foamable melt being a mixture of a pressurized melt and gas to the upward rotary surface of a coating roll from a nozzle in a state bringing the nozzle as near as possible to said rotary surface to transfer the same to a surface to be coated. CONSTITUTION:The foamable hot melt formed by a foamable hot melt applicator 6 is ejected from the nozzle 3 of a gun 4 through a supply tube 7 to be applied to the upper half surface rotating in an upward direction R of a roller 1 without generating the release and falling of said melt and the coating material FM1 is moved along with the surface of the roller 1. The coating material is leveled into a definite thickness by a doctor blade 5 to be bonded, transferred and applied to the surface of an article W to be coated under pressure. Since the moving time of the coating material is short, the reduction of the gas bubbles foamed in the foamable hot melt is not generated and the coating material can be transferred and applied to the surface to be coated without losing the characteristic thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method and apparatus for applying a foamable melt or liquid using a coating roll.

[Prior Art] The conventional roll coating method for a foamable melt or foamable liquid, which is a mixture of a melt or a liquid and a gas, is carried out by immersing the roll in the foamable melt. It was something. An example of this is shown in FIG. 4, which is an explanatory diagram of a roll-type transfer method for foaming hot melt (adhesive). Foaming hot melt FM
, are fed into the pan 73, and when they reach a fixed level, the roll 71 immersed therein is rotated. The foamed hot melt FM adhering to the roll surface comes out onto the above level as the roll 71 rotates, and after being leveled to a constant thickness FM by the doctor blade 75, it runs in contact with the roll 71. Transfer coating FM on the surface of the object W,. It will be done.

[Problem to be solved] However, the above method had one major drawback.

As mentioned above, it is a foamed hot melt FM immediately after production.
, is discharged into the pan 73, it is once quantified and then stored for a certain period of time.During this time, many fine air bubbles in the foamed hot melt are released into the atmosphere and expand, which increases over time. With the passage of time, many of them combine with each other and become coarse, or burst and disappear. That is, the number of bubbles decreased and the characteristics of the foamed hot melt were lost.

The motive of the present invention was to carry out transfer coating of a foamed hotmelt without reducing the air bubbles in the foamed hotmelt, ie, without losing its properties.

[Means for Solving the Problems] The gist of the present invention is to direct a foaming melt or foaming liquid, which is a melt or a mixture of liquid and gas, produced under pressure, from a nozzle to a roll surface. This is a method and an apparatus for discharging it onto the surface of the object and then transfer-coating it onto the surface of the object to be coated within a short period of time.

Next, the method of the present invention will be explained. Please refer to FIG. 1, which shows a foaming hot melt applicator 6 used in experiments of the present invention, although there are various methods for producing a foaming melt or foaming liquid. The outline is that hot melt (adhesive) is first melted by electric heating, and gas is pressurized into it using double gears. The pressure at this time is relatively high (40 to 70 kg/d>), and the gas is mixed into the hot melt melt in the form of fine invisible bubbles.They are discharged into the atmosphere from the nozzle. When coated, these bubbles expand and become visible bubbles.The expansion force of the bubbles allows the hot melt to penetrate into minute gaps on the surface of the object to be coated, thereby increasing the adhesion of the hot melt.

However, there is a limit to the time required for the bubble expansion process described above.

After a certain period of time has passed, not only does the expansion stop, but the bubbles combine with each other, become coarser, and even burst, causing the number of bubbles to be lost.When this happens, the properties of the foamed hotmelt are also lost. I'm going. In order to prevent this, the hot melt foam must adhere to the surface of the object within a short period of time after it is dispensed. Although it is difficult to quantitatively limit this period of time, it is usually less than 1 second. There is no doubt that it takes less than 10 seconds at most, and the method of the present invention makes it extremely easy to execute.

The generated foamed hot melt is discharged from the tip of the nozzle 3 via the gun 4, but at this time, its position is as close as possible to the contact point between the roll 1 and the object W to be coated, that is, the application portion.

It is desirable that the material be ejected onto the upper half of the rotating roll at an acute angle (α) to the tangent at that point, and the shape of the ejected material depends on the shape of the nozzle hole. However, various shapes such as a thin shape, a band shape, a plate shape, an intermittent dot shape, a square strip shape, etc. can be considered. Then, they move together with the roll, are smoothed to a uniform thickness by a doctor blade 5, and are then transferred and coated onto the surface of the object W that is moving in contact with the roll 1. During this time, the time can not only be on the order of several seconds, but also within a comma scale by further shortening the distance lIIL between the nozzle and the application section. These times vary depending on the type of foamable melt, but are generally within the applicable range.

In this way the foamable melts are bonded without losing their properties.

In addition, although the above description has been made regarding the case of roll-type transfer coating, this can also be applied to belt-type transfer coating. In the same system, as shown in FIG. 2, a flexible belt is used which has an incompatibility with heated melting substances. In this case, since the foamable melt discharged from the nozzle 13 is discharged on a horizontal plane, it has the advantage that even when the viscosity is particularly low, it is less likely to flow down and cause the pattern to collapse.

Also. It is also possible to apply transfer coating by discharging a foamable molten material from a nozzle onto a flat plate that has been given an incompatibility with heated molten substances, and then covering and pressing a sheet to be coated on top of the foamed molten material. . These operations can be done manually, but
FIG. 3 shows a method for automatically performing this process. That is, the applicator plate 21 on a flat plate is reciprocated, and in the first half S of the forward stroke S, the foamable melt is applied to the nozzle 23.
The coating material FM is then discharged onto the surface of the coating plate 21 (FMS), and after the plate moves forward through the latter half of the stroke S and stops, the coating material FM is applied from above onto the coating material at that position. In this method, sheets W and b are placed over each other and pressure is applied to transfer and coat the foamable melt onto the sheets.

Note that although the above description has been made regarding a foamable melt that is a mixture of a melt and a gas, the same can be applied to a foamable liquid that is a mixture of a liquid and a gas.

Next, the structure of the device based on the above method will be explained.

Referring also to FIG. 1, the roll 1 is connected to a rotary drive 2 in the conventional manner. Further, the tips of the gun 4 and its nozzle 3 connected to the foamed hot melt generating device 6 are placed on the surface of the upper half of the roll 1 and toward the rotational direction 'R# of the roll. It is desirable that the nozzle be oriented on the upper half of the nozzle and be placed at an acute angle (α) to the tangent at the point of contact on the centerline of the nozzle. Furthermore, the nozzle 3 and the application part spp
A doctor blade 5 is provided between the t and t if necessary.

It is desirable that the doctor blade forms a non-perpendicular angle β with respect to the rotational direction R of the roll, as shown in the plan view of its installation in FIG. 1A. In addition, when doctoring a relatively thick discharged material, the doctor blade should be installed with the cutting edge $5T held at the above two angles α and β1 as shown in Figure 1B. under,
It is desirable that the finishing process be performed with a radius equal to the radius r of the roll plus the thickness t of the transfer coating, that is, x+t.

Note 5: When the above-mentioned nozzle is provided in the lower half of the roll 1 in the upward rotation direction (3
In A), the doctor blade installed after that is.

As shown by the imaginary line in the same figure (5A). Rotation direction #R#
It may be perpendicular to the roll axis, that is, parallel to the roll axis. Further, the nozzle hole of the nozzle 3 may be of any desired shape, such as a round shape, a slit shape, or a slot shape.

[Effect] Please refer to Figure 1 again. The figure shows the case of foaming hot melt as mentioned above. The foamed hot melt produced by the foamed hot melt applicator 6 passes through a supply tube 7, passes through a gun 4, is discharged from a nozzle 3, and is sprayed onto the surface of the rotating roller 1. At this time, the discharged material F
Since the M workpiece is on the surface that rotates in the upward direction nRn of the upper half of the roller 1, it does not peel off and fall downward, and the discharged workpiece FM1 moves together with the roller 1.

Then, it is smoothed to a constant thickness by the doctor blade 5, continues to move, encounters the surface of the object W to be coated, is pressed, and is transferred and coated onto the surface. Since the above-mentioned transfer time is short, the bubbles formed in the foamed hot melt do not decrease, and transfer coating can be performed on the surface of the object to be coated without losing its properties.

The excess foamed melt scraped off by the doctor blade 5 moves forward along the inclination of the doctor blade and is discharged to the outside of the roll 1. However, if the doctor blade is provided on the lower half surface of the roll 1, even if the doctor blade 5A is perpendicular to the rotational direction R, the excess foamed melt that has been scraped off will be removed by its own weight. It falls downward.

Although the case of a foaming hot melt has been described above, the same effect can be achieved in the case of other foaming melts or foaming liquids.

[Examples] 1. First Example In this example, a coating belt was used in place of the coating roll in the above specific invention. The structure is shown in FIG. 2, an endless flat belt 11 coated with a release agent, etc.
is driven by a drive device 12 in a fixed direction 〃R1〉. A backup roll 10 is provided between the belt drive roll 9A and the driven roll 9B, extending upward from below the belt, and a pressure roll 19 is provided above the belt in opposition to the backup roll. provided.

Next, a foamable melt discharge nozzle 13 is provided on the belt and on the front side of the pressure roll 19 (in the belt traveling direction) at a required distance L1, facing the surface of the belt 11. Further, the nozzle gun 14 is arranged 11 (17) and connected to the foamable melt producing device 16, and further connected by wire to the controller 18 in parallel.

Depending on the situation, the nozzle and the doctor blade may be provided on the surface of the application belt 11 running on the surface of the driven roller 98 for belt running, as shown by the imaginary line in the figure (13A, 15A).

Next, the operation of the coating device described above will be explained. The foamable melt is discharged onto the surface of the flat belt 11 running at a required speed. The discharge material FM3 moves on the flat belt 11, reaches under the pressure roll 19, contacts and is pressurized by the object to be coated WI advancing along the roll, and is coated with the discharge material. A certain foamable melt FM3 is transfer-coated onto the surface of the object to be coated W0.

20 Second Embodiment In this example, a flat coating plate was used in place of the coating roll and coating belt described above. An applicator plate 21, a side view of which is shown in FIG. 3, is fixed on a reciprocating plate 20, which plate is connected via a rod 22 to an air cylinder 29. A foamable melt discharge nozzle 23 is provided facing the coating plate 21 above the inside and upper tip of the forward end of the reciprocating plate 20 in the traveling direction at the most retracted position of the stroke S of the air cylinder. And the stroke S of the reciprocating plate 20
A coating device 1241 for a sheet, which is an object to be coated, is provided on the outer side of the most advanced position, and this device is also connected to the air cylinder 42 . The above gun 24 and two types of air cylinders 29.4
2 are connected to the solenoid type air eight-way switching operation valves 36 and 55, respectively, and these solenoids are wired to the controller 28. Furthermore, if necessary, a sheet feeding device 40
and discharge device t! 60, an independent pressurizing device 50, etc. are further added.

Next, the operation of the coating device described above will be explained. First, in response to a signal from the controller 28, the air cylinder 29 of the reciprocating actuator 31 is activated via the solenoid type air eight-way switching operation valve 35.
starts from the starting point of the stroke, thereby causing the reciprocating plate 20 to begin moving. In accordance with this, the gun 24 is opened according to a signal from the controller 28, and the foaming melt is discharged (FM) onto the reciprocating plate 20. As the applicator plate 21 moves, the foaming melt is applied continuously and intermittently by the intermittent opening and closing of the gun 24. The moving applicator plate 21 continues to move, and at a slightly forward portion of the rear end of the applicator plate 21 (at the end of the first half of the stroke S1), the gun 24
is closed and discharge is interrupted. Further, the application plate 21 continues to move and stops at the end point of the remaining stroke S2. Subsequently, the sheet feeding device 40 and the coating device 41 are operated in accordance with the signals from the controller 28 in the same manner as described above. That is, one sheet W3 is supplied from the sheet supply device 40, and the sheet is stored on the sheet holder 44 in the coating device 41.

Then, the air cylinder 42 of the coating device 41 is actuated via the solenoid type air eight-way switching operation valve 55 in response to a signal from the controller 28, as described above, so that the sheet pedestal 44 is reversed about the fulcrum 46. , is placed over the above-mentioned discharged foamable melt FM, and is further pressurized and crimped by the sheet pedestal 44 by the above-mentioned air cylinder 42. In this way, the foamable melt FM is transfer-coated onto the surface of the sheet W.

[Effects of the Invention] According to the method and apparatus of the present invention, in transfer application of a pressurized melt or a mixture of a liquid and a gas, such as a foaming melt or a foaming liquid, through a roll, After they are discharged from a nozzle onto the roll surface, they are transferred and coated onto the surface of the object to be coated within a short time, without losing the characteristics of the foaming melt or foaming liquid at the time of transfer coating. Transfer coating can be performed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory side cross-sectional view of the method and apparatus of the present invention.
Figure A is a plan view of the installed state of the doctor blade. Figure 18 is a diagram of the cutting edge of the wide doctor blade. Figure 2 is the top view of the installed state of the doctor blade.
Figure 2A is a side view of the device in the embodiment; Figure 2A is a plan view of the doctor blade in the attached state; Figure 3 is a side view of the device in the second embodiment; Figure 3A is a plan view of the doctor blade in the attached state; Fig. 4 is an explanatory diagram of a side cross section of a conventional roll-type transfer coating device for foaming melt and explanation of main symbols.

Claims (1)

[Claims] 1. With respect to the upward facing surface of the rotating coating roll (1), place the coating portion (P) as close as possible to the coating portion (P) where the surface and the object to be coated (W) come into contact (L). A foamable melt, which is a mixture of pressurized melt and gas, is discharged from a nozzle (3) and sprayed onto the coating roll (1) surface (FM_1), and then the sprayed material is A method for applying a foamable melt material, which is characterized in that transfer coating is performed on the surface of an object (W) to be coated within a short period of time. 2. The method for coating a foamable melt according to claim 1, wherein the rotating coating roll (1) is a running coating belt (11). 3. During the first half of the reciprocating movement of the applicator plate (21), a gun (24) sprays a foamable melt, which is a mixture of pressurized melt and gas, onto the applicator plate surface. Nozzle (23
) and subsequently, in the latter half of the same operation, the material to be coated (W_3_6) is covered on the material to be coated (W_3_6) and pressure is applied to apply the foamable melt. Method. 4. Claim 1 or 2 in which the melt is a liquid
3. A method for applying a foaming liquid according to item 3. 5. Application roll (1) connected to rotation drive device (2)
(d) Foaming, which is a mixture of pressurized melt and gas, is applied to the surface as close as possible to the application part ("P") where the application roll and the object to be coated (W) come into contact. 1. A coating device for a foamable melt, comprising: a gun (4) and a nozzle (3) for discharging the foamable melt. 6. The foamable melt coating device according to claim 5, wherein the coating roll (1) is a coating belt (11). 7. The foamable melt coating device according to claim 5 or 6, wherein a doctor blade (5 or 15) is provided between the nozzle and the coating section. 8. a. A reciprocating applicator plate (21), and b. Pressurized melt and gas directed toward the reciprocating applicator plate on the first half of one stroke of the reciprocating applicator plate (21). A gun (24) and a nozzle (23) for discharging the foamable melt, which is a mixture, are provided, and c. An object sheet (W_
3) A coating device for a foamable melt, characterized in that the coating device (41) is provided. 9. In the first half of the stroke according to Claims 8-6 above, a doctor blade (25) is provided on the side in the advancing direction of the stroke from the nozzle (23). 10. The foamable body coating device according to claim 5, 6, 7, or 8, wherein the melt is a liquid.