JP2009095687A - Method and apparatus for coating liquid, absorbing article and method of manufacturing the article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent hooking at the beginning of coating with a spiral spray. <P>SOLUTION: A liquid coater 1 for coating a substrate with a liquid has a liquid discharge hole 15, two or more air spraying holes 17 formed around the liquid discharge hole and spraying compressed air in such a way as to make the compressed air nearly in contact with the outer periphery of the beads of the liquid discharged from the liquid discharge hole, a valve 31 carrying out starting and stopping of the discharge of the liquid from the liquid discharge hole, a pressure switching device 50 switching the pressure of the compressed air sprayed from the air spraying holes between the first pressure and the second pressure higher than the first pressure, and a controller 63 controlling the pressure switching device so as to spray compressed air at the first pressure during stopping of the discharge of the liquid and to spray compressed air at the second pressure at the same time as the beginning of the discharge of the liquid or a specified time after the beginning of the discharge of the liquid. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and apparatus for applying a liquid, an absorbent article, and a method for manufacturing the same.

  Conventionally, there is a spiral spray gun using a controlled fiberization method. Spiral spray guns discharge hot melt as a single continuous bead and apply hot air to the bead to stretch the hot melt bead and apply it to the substrate in a continuous fiber state without breaking into a spiral. .

  FIG. 6 is a view showing a conventional liquid coating apparatus 101. The liquid application apparatus 101 includes a spiral spray gun 103 that applies hot melt as a liquid to a substrate. Further, the liquid coating apparatus 101 includes a hot melt supply system 102 that supplies hot melt to the spiral spray gun 103 and a valve body operating air supply system that supplies compressed air for controlling discharge of the hot melt to the spiral spray gun 103. 104 and a hot air supply system 106 that supplies hot air that gives a swirl motion to the hot melt fiber to the spiral spray gun 103.

The spiral spray gun 103 includes a hot melt valve 105 and a spiral nozzle 107.
The spiral nozzle 107 has a hot melt discharge hole 108 and a plurality of hot air discharge holes 110 around the hot melt discharge hole 108. The hot melt is discharged from the hot melt discharge hole 108 to form a hot melt bead. The plurality of hot air ejection holes 110 are oriented so that the pressurized hot air ejected from the plurality of hot air ejection holes 110 substantially contacts the outer periphery of the hot melt bead. The pressurized hot air stretches the hot melt bead into a fiber shape, and imparts a swirling motion to the stretched hot melt fiber to form the spiral spray pattern 112.

  The hot melt supply system 102 includes a hot melt tank 109. Hot melt is supplied from the hot melt tank 109 to the hot melt inlet 111 of the spiral spray gun 103.

  The hot melt is sent from a hot melt inlet 111 to a hot melt chamber 119 formed inside the hot melt valve 105. A valve seat 123 is provided at the outlet 121 of the hot melt chamber 119. The valve body 125 moves between a closed position in which the valve seat 123 abuts and closes the outlet 121, and an open position in which the outlet 121 is opened away from the valve seat 123 and the hot melt chamber 119 communicates with the hot melt passage 127. it can. The valve body 125 is provided at one end of the valve rod 126. A piston 129 is provided at the other end of the valve rod 126. The piston 129 is slidable in a cylinder chamber 131 formed inside the hot melt valve 105.

  The valve body operating air supply system 104 includes an air regulator 133 and an electromagnetic valve 135. The compressed air is adjusted to a predetermined pressure by the air regulator 133 and sent to the electromagnetic valve 135. The pressure-adjusted compressed air is sent to the cylinder chamber 131 through the compressed air inlet 130 of the hot melt valve 105 when the electromagnetic valve 135 is opened. Thereby, the compressed air moves the piston 129 in the cylinder chamber 131 upward, and moves the valve rod 126 upward. The valve body 125 opens away from the valve seat 123 and opens the outlet 121. Hot melt in the hot melt chamber 119 passes through the hot melt passage 127 from the outlet 121 and is discharged as a hot melt bead from the hot melt discharge hole 108 communicating with the hot melt passage 127.

  When the electromagnetic valve 135 is closed, the supply of compressed air to the cylinder chamber 131 is stopped and the cylinder chamber 131 is opened to the atmosphere. As a result, the piston 129 is moved downward by the urging force of the spring 137 provided in the hot melt valve 105 and moves the valve rod 126 downward. The valve body 125 abuts on the valve seat 123 to close the outlet 121 and stops the discharge of the hot melt beads from the hot melt discharge hole 108.

  The hot air supply system 106 includes an air regulator 113 and a hot air manifold 115. The compressed air is adjusted to a predetermined pressure by the air regulator 113 and sent to the hot air manifold 115. The compressed air is heated by the hot air manifold 115 and supplied as pressurized hot air from the hot air manifold 115 to the hot air inlet 117 of the spiral spray gun 103. The pressurized hot air is sent from the hot air inlet 117 to the hot air chamber 141 through the hot air passage 139. Since the hot air chamber 141 communicates with the plurality of hot air ejection holes 110, the pressurized hot air is ejected from the plurality of hot air ejection holes 110. The pressurized hot air stretches the hot melt bead discharged from the hot melt discharge hole 108 into a fiber shape, and imparts a swirling motion to the stretched hot melt fiber to form the spiral spray pattern 112.

  The operation of the conventional liquid coating apparatus 101 will be described below.

  When the liquid coating apparatus 101 starts operating, the compressed air is adjusted to a predetermined pressure by the hot air supply system 106 and heated, and is constantly supplied to the hot air inlet 117. Thereby, the pressurized hot air is constantly ejected from the plurality of hot air ejection holes 110 provided in the spiral nozzle 107. At this time, the flow rate of the pressurized hot air that is constantly ejected from the plurality of hot air ejection holes 110 is sufficient to swirl the drawn hot melt fiber to obtain a spiral coating pattern having a desired coating width W. This is the flow rate required to give motion.

  When the electromagnetic valve 135 is opened to start application of hot melt to the substrate, the compressed air raises the piston 129 to release the valve body 125 from the valve seat 123 and open the outlet 121. As a result, the hot melt in the hot melt chamber 119 is discharged from the hot melt discharge hole 108 of the spiral nozzle 107 through the hot melt passage 127.

  The hot melt discharged from the hot melt discharge hole 108 forms a hot melt bead. The pressurized hot air ejected from the plurality of hot air ejection holes 110 comes into contact with the outer periphery of the hot melt bead. The hot melt bead becomes a hot melt fiber drawn by pressurized hot air, and a swirl motion is imparted to the drawn hot melt fiber to form a spiral spray pattern 112. The spiral spray pattern 112 is attached on a substrate that moves relative to the spiral spray gun 103 to form a spiral coating pattern.

  In addition to the conventional liquid application apparatus 101, a liquid application method and apparatus for preventing a hook phenomenon due to spiral spray have been proposed (see, for example, Patent Document 1). The liquid coating apparatus of Patent Document 1 is adjacent to the hot melt discharge hole in addition to the air injection hole for bringing the hot melt bead into a hot melt fiber by bringing the pressurized air into contact with the hot melt bead. The second air injection hole is provided. The hook phenomenon is prevented by causing the pressurized air from the second air injection hole to act on the hot melt bead prior to the hot melt bead contacting the pressurized air from the air injection hole.

Japanese Patent Laid-Open No. 9-136053 (paragraphs 0012 to 0014, FIGS. 1, 6, 8, and 10)

When the spiral spray pattern 112 is formed by the conventional liquid coating apparatus 101 shown in FIG. 6 and attached to the substrate, a hook is generated at the start of coating.
FIG. 7 is a diagram showing a spiral application pattern adhered on a substrate. FIGS. 7A, 7B, and 7C show spiral application patterns 151, 153, and 155 attached on the substrate 150, respectively. The substrate 150 is conveyed in the direction indicated by the arrow X, and the broken line P indicates the application start position. The spiral application pattern has a desired application width W.

  When the hot hot beads ejected from the plurality of hot air ejection holes 110 come into contact with the tips of the hot melt beads ejected from the hot melt ejection holes 108 at the start of coating, before the spiral spiral pattern is formed. The tip of the hot melt bead is blown away in an unpredictable direction. For this reason, the tip of the hot melt bead adheres to an unspecified position on the base material 150 to generate hooks HA, HB, and HC.

In FIG. 7A, the hook HA exists inside the desired application width W, but protrudes greatly from the application start position P to the outside.
In FIG. 7B, the hook HB protrudes greatly above the desired application width W and also protrudes outward from the application start position P.
In FIG. 7C, the hook HC protrudes greatly below the desired application width W and also protrudes outward from the application start position P.

  As described above, the tip of the hot melt bead discharged from the spiral spray nozzle 107 at the start of coating greatly deviates from the expected pattern coating start position P and the expected pattern coating width W before starting to turn. Adhere to the position. And the position to which it adheres is not decided, it cannot be predicted, and it changes for every application start. The hook may be present within the expected coating width W, but may be attached to a position separated by about five times the coating width W.

  As a result, the hot melt is applied to a position that is not required, so that a product defect occurs or the manufacturing machine is soiled to reduce productivity. In addition, the hook-shaped hot melt bead tip becomes a lump having a width of 3 to 10 times the diameter of the hot melt fiber forming the spiral pattern (teall-like drops, large drop of drops). The retained heat of the hot melt bead melts the product and makes holes, loses the uniformity of the product, damages the surface of the product, and the adhesive strength is too strong.

  An object of this invention is to provide the liquid application method and apparatus which can prevent the hook at the time of the start of application | coating in spiral spray.

In order to solve the above-described problems, the present invention adopts the following method.
That is, in a method of applying a liquid to a substrate,
A first injection step of injecting pressurized air at a first pressure from a plurality of air injection holes;
A discharge step of discharging the liquid in a bead shape from the liquid discharge hole;
Providing a second injection step of injecting pressurized air from the plurality of air injection holes so as to contact the liquid bead at a second pressure higher than the first pressure;
By starting the second injection step simultaneously with the start of the discharge step or after a predetermined time delay from the start of the discharge step, the pressurized air is brought into contact with the tip of the liquid bead at the first pressure, and then the first A method of applying a spiral coating pattern of liquid on a substrate by bringing pressurized air into contact with a liquid bead at two pressures and stretching to form a liquid fiber, and applying a swirling motion to the liquid fiber.

In the present invention, the following liquid coating apparatus is used.
That is, in the liquid application device (1) for applying a liquid to a substrate,
A liquid discharge hole (15);
A plurality of air injection holes (17) provided around the liquid discharge holes and for injecting pressurized air so as to substantially contact the outer periphery of the beads of the liquid discharged from the liquid discharge holes;
A valve body (31) for starting and stopping the discharge of liquid from the liquid discharge hole;
A pressure switching device (50) for switching the pressure of the pressurized air injected from the plurality of air injection holes between a first pressure and a second pressure higher than the first pressure;
The pressure switching device is configured to inject pressurized air at a first pressure while stopping liquid discharge, and to inject pressurized air at a second pressure simultaneously with the start of liquid discharge or after a predetermined time delay from the start of liquid discharge. And a control device (63) for controlling.

Moreover, in this invention, it was set as the manufacturing method of the following absorbent articles.
That is, in the method for manufacturing an absorbent article,
A transporting process for transporting the absorbent substrate in a predetermined direction;
A first injection step of injecting pressurized air at a first pressure from a plurality of air injection holes;
A discharge step of discharging the liquid in a bead shape from the liquid discharge hole;
A second injection step of injecting pressurized air from the plurality of air injection holes so as to contact the liquid bead at a second pressure higher than the first pressure;
By starting the second injection step simultaneously with the start of the discharge step or after a predetermined time delay from the start of the discharge step, the pressurized air is brought into contact with the tip of the liquid bead at the first pressure, and then the first At two pressures, pressurized air is brought into contact with the liquid bead and stretched to form a liquid fiber, and the liquid fiber is swirled to attach a liquid spiral coating pattern on the absorbent substrate being conveyed. And a process for producing an absorbent article.

  Moreover, in this invention, the absorbent article manufactured with the said manufacturing method is provided.

  According to the present invention, it is possible to prevent a hook at the start of spiral spray application.

  Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

  FIG. 1 is a diagram showing a liquid coating apparatus 1 according to the present invention. The liquid coating apparatus 1 includes a spiral spray gun 3 that applies hot melt as a liquid to a substrate. The liquid coating apparatus 1 includes a hot melt supply system 5 that supplies hot melt to the spiral spray gun 3 and a valve body operating air supply system that supplies compressed air for controlling the discharge of the hot melt to the spiral spray gun 3. 7 and a hot air supply system 9 for supplying hot air to the spiral spray gun 3 for applying a swirling motion to the hot melt fiber.

The spiral spray gun 3 includes a hot melt valve 11 and a spiral nozzle 13.
The spiral nozzle 13 has a hot melt discharge hole 15 as a liquid discharge hole, and a hot air ejection hole 17 as a plurality of air ejection holes around the hot melt discharge hole 15. The hot melt is discharged from the hot melt discharge hole 15 to form a hot melt bead. The plurality of hot air ejection holes 17 are oriented so that the pressurized hot air ejected from the plurality of hot air ejection holes 17 substantially contacts the outer periphery of the hot melt bead. The pressurized hot air draws a hot melt bead into a fiber shape, and imparts a swirling motion to the drawn hot melt fiber to form a spiral spray pattern 19.

  The hot melt supply system 5 includes a hot melt tank 21. Hot melt is supplied from the hot melt tank 21 to the hot melt inlet 23 of the spiral spray gun 3.

  The hot melt is sent from the hot melt inlet 23 to a hot melt chamber 25 formed inside the hot melt valve 11. A valve seat 29 is provided at the outlet 27 of the hot melt chamber 25. The valve body 31 moves between a closed position in which the valve seat 29 abuts and closes the outlet 27, and an open position in which the outlet 27 is opened away from the valve seat 29 and the hot melt chamber 25 communicates with the hot melt passage 33. it can. The valve body 31 is provided at one end of the valve rod 35. A piston 37 is provided at the other end of the valve stem 35. The piston 37 is slidable in a cylinder chamber 39 formed inside the hot melt valve 11.

  The valve body working air supply system 7 includes an air regulator 41 and an electromagnetic valve 43. The compressed air is adjusted to a predetermined pressure by the air regulator 41 and sent to the electromagnetic valve 43. The pressure-adjusted compressed air is sent to the cylinder chamber 39 through the compressed air inlet 45 of the hot melt valve 11 when the electromagnetic valve 43 is opened. Thereby, the compressed air moves the piston 37 in the cylinder chamber 39 upward, and moves the valve rod 35 upward. The valve body 31 opens away from the valve seat 29 and opens the outlet 27. The hot melt in the hot melt chamber 25 passes through the hot melt passage 33 from the outlet 27 and is discharged as a hot melt bead from the hot melt discharge hole 15 communicating with the hot melt passage 33.

  When the solenoid valve 43 is closed, the supply of compressed air to the cylinder chamber 39 is stopped and the cylinder chamber 39 is opened to the atmosphere. As a result, the piston 37 is moved downward by the urging force of the spring 47 provided in the hot melt valve 11 and moves the valve rod 35 downward. The valve body 31 abuts on the valve seat 29 to close the outlet 27 and stops the discharge of the hot melt bead from the hot melt discharge hole 15.

  The hot air supply system 9 includes an air regulator 49, a throttle valve 51, a solenoid valve 53, and a hot air manifold 55. The compressed air is adjusted to a predetermined pressure by the air regulator 49. The compressed air whose pressure has been adjusted is sent to the throttle valve 51 and the electromagnetic valve 53. The throttle valve 51 is shown as a variable throttle valve, but may be a fixed throttle valve.

The throttle valve 51 adjusts the flow rate of the compressed air flowing from the air regulator 49 to the hot air manifold 55 to the first predetermined flow rate when the electromagnetic valve 53 is closed.
When the electromagnetic valve 53 is opened, the flow rate of the compressed air flowing from the air regulator 49 to the hot air manifold 55 through the throttle valve 51 and the electromagnetic valve 53 becomes the second predetermined flow rate.

  The compressed air is heated by the hot air manifold 55 and supplied as pressurized hot air from the hot air manifold 55 to the hot air inlet 57 of the spiral spray gun 3. The pressurized hot air is sent from the hot air inlet 57 to the hot air chamber 61 through the hot air passage 59. Since the hot air chamber 61 communicates with the plurality of hot air ejection holes 17, the pressurized hot air is ejected from the plurality of hot air ejection holes 17. The pressurized hot air stretches the hot melt bead discharged from the hot melt discharge hole 15 into a fiber shape, and imparts a swirling motion to the stretched hot melt fiber to form a spiral spray pattern 19.

  The throttle valve 51 and the electromagnetic valve 53 constitute a pressure switching device 50 that switches the pressure near the inlet M of the hot air manifold 55. The pressure switching device 50 can change the flow rate of the pressurized hot air ejected from the plurality of hot air ejection holes 17 by switching the pressure of the compressed air near the inlet M.

  When the electromagnetic valve 53 is closed, the throttle valve 51 throttles the compressed air flowing from the air regulator 49 to the hot air manifold 55, and the pressure near the inlet M of the hot air manifold 55 is set to the first predetermined pressure. Thus, the flow rate of the pressurized hot air ejected from the plurality of hot air ejection holes 17 is set to the first predetermined flow rate. The pressurized hot air of the first predetermined flow rate draws the hot melt bead discharged from the hot melt discharge hole 15 into a fiber shape, and imparts a small swirl motion to the drawn hot melt fiber. The diameter of this small swivel motion is much smaller than the desired application width W of the helical application pattern to be deposited on the substrate and should be about one-half or less. Preferably, the diameter is about one third or less, about one quarter or less, or about one fifth. If the first predetermined flow rate is large, the swirling motion of the hot melt fiber becomes large, which causes a hook. On the other hand, if the first predetermined flow rate is too small, the hot melt fiber is not swirled, so that the mass at the tip of the hot melt fiber becomes large.

  On the other hand, when the solenoid valve 53 is opened, the solenoid valve 53 permits the flow of compressed air flowing from the air regulator 49 through the solenoid valve 53 to the hot air manifold 55, so that the pressure near the inlet M of the hot air manifold 55 is the first. (2) Become a predetermined pressure. Thereby, the flow rate of the pressurized hot air ejected from the plurality of hot air ejection holes 17 becomes the second predetermined flow rate. The pressurized hot air at the second predetermined flow rate is obtained by drawing the hot melt bead discharged from the hot melt discharge hole 15 into a fiber shape, and imparting a swirling motion to the drawn hot melt fiber so as to form a desired spiral shape. A spray pattern 19 is formed. When the desired spiral spray pattern 19 adheres to the substrate, it forms a spiral application pattern having a desired application width W.

  The second predetermined pressure is greater than the first predetermined pressure. The second predetermined pressure is a flow rate of pressurized hot air that can impart sufficient swirling motion to the stretched hot melt fiber in order to obtain a spiral coating pattern having a desired coating width W (in this embodiment). Is the pressure required to obtain the second predetermined flow rate). The first predetermined pressure may be about one half to about one quarter of the second predetermined pressure, and preferably about one third.

  The solenoid valve 43 and the solenoid valve 53 are electrically connected to the control device 63. The control device 63 controls the opening / closing of the electromagnetic valve 43 and the opening / closing of the electromagnetic valve 53.

FIG. 2 is a diagram conceptually illustrating an example of a spiral application pattern attached on a substrate. The substrate 65 was conveyed in the direction indicated by the arrow X. A broken line P indicates the application start position. The spiral application pattern 67 attached on the substrate 65 has a desired application width W.
The tip 67LE of the spiral application pattern 67 is within the desired application width W and does not protrude from the application start position P. That is, the occurrence of hooks could be prevented.

  The operation of the liquid coating apparatus 1 of the present invention will be described below.

  FIG. 3 is a time chart showing the start and stop of hot melt discharge and the start and stop of hot air injection in the first embodiment.

  When the liquid coating apparatus 1 starts operating, the compressed air is adjusted to a predetermined pressure by the air regulator 49 and supplied to the throttle valve 51. At this time, since the electromagnetic valve 53 is closed, the compressed air is throttled by the throttle valve 51, and the pressure in the vicinity of the inlet M of the hot air manifold 55 is maintained at the first predetermined pressure. In this example, the first predetermined pressure was set to 0.012 MPa. Thereby, the pressurized hot air is injected at a first predetermined flow rate from the plurality of hot air injection holes 17 provided in the spiral nozzle 13 (first injection step).

  In order to start the application of the hot melt to the base material, the control device 63 opens the electromagnetic valve 43 of the valve body operating air supply system 7 and the electromagnetic valve 53 of the hot air supply system 9 simultaneously at time T1 in FIG. .

  When the electromagnetic valve 43 is opened, the compressed air raises the piston 37 to release the valve body 31 from the valve seat 29 and open the outlet 27. Thereby, the hot melt in the hot melt chamber 25 passes through the hot melt passage 33 and is discharged from the hot melt discharge hole 15 of the spiral nozzle 13 (discharge step). The hot melt discharged from the hot melt discharge hole 15 forms a hot melt bead. The pressurized hot air ejected from the plurality of hot air ejection holes 17 comes into contact with the outer periphery of the hot melt bead. At this time, the flow rate of the pressurized hot air ejected from the plurality of hot air ejection holes 17 is still the first predetermined flow rate or a flow rate slightly higher than the first predetermined flow rate. Therefore, the hot melt bead is drawn by hot hot air to form a hot melt fiber, but the swirl motion imparted to the drawn hot melt fiber is small. Thus, the tip of the hot melt bead can be prevented from being blown away in an undesired direction, and the hot melt bead can be drawn into a hot melt fiber shape.

  When the solenoid valve 43 of the hot air supply system 9 is opened simultaneously with the opening of the solenoid valve 43 of the valve body operating air supply system 7, the solenoid valve 53 flows from the air regulator 49 through the solenoid valve 53 to the hot air manifold 55. Since the flow of compressed air is permitted, the pressure in the vicinity of the inlet M of the hot air manifold 55 becomes the second predetermined pressure. In the present example, the second predetermined pressure was set to 0.031 MPa. Thus, the pressurized hot air is injected at a second predetermined flow rate from the plurality of hot air injection holes 17 provided in the spiral nozzle 13 (second injection step).

  The solenoid valve 43 of the valve body operating air supply system 7 and the solenoid valve 53 of the hot air supply system 9 are simultaneously opened at time T1 in FIG. 3, but the second predetermined flow rate of pressurized hot air contacts the hot melt bead. This is after the first predetermined flow rate of pressurized hot air contacts the tip of the hot melt bead. Therefore, even if the pressurized hot air at the second predetermined flow rate contacts the hot melt bead, the tip of the hot melt bead is not greatly blown away in an undesired direction. The pressurized hot air at the second predetermined flow rate is obtained by drawing a hot melt bead discharged from the hot melt discharge hole 15 into a fiber shape, and imparting a swirling motion to the drawn hot melt fiber to form a desired spiral shape. A spray pattern 19 is formed. As a result, a spiral coating pattern having a desired coating width W is formed on the substrate that moves relative to the spiral spray gun 3.

  In the first embodiment, the solenoid valve 43 of the valve body operating air supply system 7 and the solenoid valve 53 of the hot air supply system 9 are simultaneously closed at time T2 in FIG.

According to this embodiment, it is possible to prevent the occurrence of hooks at the start of spiral spray application. And the amount of hot melt used can be reduced by reducing hooks. In addition, since the device can be prevented from being contaminated with the hook, the maintenance of the device can be simplified.
Furthermore, according to the embodiment, while the hot melt discharge is stopped, the air flow rate is reduced to about one third of the conventional amount, so that the amount of air used can be greatly reduced.
According to the present embodiment, the lump at the tip of the hot melt bead at the start of application can be made small, so that the base material can be prevented from being melted by the heat retained by the hot melt bead. Therefore, it is possible to apply the hot melt bead to a base material that is thinner than the conventional one.

  The second embodiment has the same configuration as that of the first embodiment shown in FIG. The difference from the first embodiment is the opening / closing timing of the electromagnetic valve 43 of the valve element operating air supply system 7 and the electromagnetic valve 53 of the hot air supply system 9 by the control device 63.

  FIG. 4 is a time chart showing the start and stop of hot melt discharge and the start and stop of hot air injection in the second embodiment.

  In Example 1, the control device 63 simultaneously opened the electromagnetic valve 43 of the valve element operating air supply system 7 and the electromagnetic valve 53 of the hot air supply system 9 at time T1 in FIG. In the second embodiment, the time T3 for opening the electromagnetic valve 53 of the hot air supply system 9 is delayed by the time Td with respect to the time T1 for opening the electromagnetic valve 43 of the valve body operating air supply system 7. In this embodiment, the delay time Td is set to 5 milliseconds. Thereby, the favorable spiral application pattern which does not generate | occur | produce a hook was able to be obtained.

  In the second embodiment, the same effect as in the first embodiment can be obtained.

  The delay time Td varies depending on the configuration of the liquid coating apparatus, but is in the range of 0 to 100 milliseconds. Usually, 0 to 5 milliseconds, or 0 to 10 milliseconds is preferable. The delay time Td is the length from the solenoid valve 53 of the hot air supply system 9 to the hot air ejection hole 17 of the spiral nozzle 13, the volume of the hot air manifold 55, the volume of the hot air chamber 61, the spiral nozzle 13 and the base material. Depending on parameters such as the distance between.

  The tip of the hot melt bead discharged from the hot melt discharge hole 15 is first stretched in contact with the first predetermined flow rate of pressurized hot air and given a small swirling motion, and then the tip of the hot melt bead is Before adhering to the substrate, a second predetermined flow rate of pressurized hot air may be drawn into contact with the hot melt beads to be drawn into hot melt fibers, and the drawn hot melt fibers may have a desired spiral spray pattern.

  If the tip of the hot melt bead suddenly comes into contact with the first predetermined flow rate of pressurized hot air and then comes into contact with the second predetermined flow rate of pressurized hot air, the tip of the hot melt bead is blown away in an undesired direction. It will occur. On the other hand, even if the second predetermined flow rate of the pressurized hot air comes into contact with the hot melt bead after the hot melt bead tip is attached to the substrate, the hot melt bead is pulled by the tip first attached to the substrate. There is a risk of creating large lumps.

  Therefore, the tip of the hot melt bead first comes into contact with the first predetermined flow of pressurized hot air, and then the second predetermined flow of pressurized hot air is hot before the tip of the hot melt bead adheres to the substrate. The delay time Td may be set so as to contact the melt bead. However, depending on the configuration of the liquid application device, the flow rate of the pressurized hot air injected from the hot air injection hole 17 after opening the electromagnetic valve 53 of the hot air supply system 9 is the second predetermined flow rate due to the influence of the above parameters. It may take some time to reach. In that case, on the contrary, it is necessary to open the solenoid valve 53 of the hot air supply system 9 first and then open the solenoid valve 43 of the valve body operating air supply system 7.

  FIG. 5 is a view showing a liquid coating apparatus according to Embodiment 3 of the present invention. In the liquid coating apparatus 1 shown in FIG. 1, the control device 63 controls the opening / closing of the electromagnetic valve 43 of the valve body operating air supply system 7 and the opening / closing of the electromagnetic valve 53 of the hot air supply system 9. On the other hand, in the liquid coating apparatus 81 of the third embodiment, the solenoid valve 53 of the hot air supply system 9 is replaced with a spool valve type switching valve 73 that is switched by air drive, and a valve element operating air supply system is obtained. The spool valve type switching valve 73 is opened and closed by compressed air from the electromagnetic valve 43 of FIG. This eliminates the need for electrical wiring from the control device 63 to the electromagnetic valve 53, and simplifies the configuration of the control system.

  Referring to FIG. 5, a passage 72 communicating with the spool valve type switching valve 73 is connected to a passage 71 connecting the electromagnetic valve 43 of the valve body operating air supply system 7 and the compressed air inlet 45 of the hot melt valve 11. Yes. The electromagnetic valve 43 is electrically connected to the control device 70. The control device 70 controls opening and closing of the electromagnetic valve 43.

  In order to start application of hot melt to the base material, the control device 70 opens the electromagnetic valve 43 of the valve body operating air supply system 7. When the electromagnetic valve 43 is opened, compressed air is sent through the passage 71 to the cylinder chamber 38 to raise the valve body 31 and start discharging hot melt. At the same time, the compressed air passes from the passage 71 to the passage 72 and opens the spool valve type switching valve 73. As a result, the pressure in the vicinity of the inlet M of the hot air manifold 55 rises from the first predetermined pressure to the second predetermined pressure, and the injection of pressurized hot air at the second predetermined flow rate from the hot air ejection hole 17 is started. Since the internal flow path of the hot air manifold 55 is long, the pressurized hot air from the hot air ejection hole 17 rises from the first predetermined flow rate to the second predetermined flow rate because hot melt is discharged from the hot melt discharge hole 15. Slightly behind the start. Thereby, the spiral application pattern without a hook can be formed on a base material.

  Using the liquid application method shown in Examples 1 to 3, the hot melt adhesive can be applied to the absorbent base material to produce an absorbent article. The absorbent article manufactured by this method has a good texture on the product surface and good usability. Absorbent articles include napkins, diaper products, and pet care products.

  The present invention is not limited to the above embodiments, and can be implemented in various other forms without departing from the features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is shown by the scope of claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

The figure which shows the liquid application apparatus of this invention. The figure which shows notionally an example of the helical application pattern adhering on the base material. 3 is a time chart showing the start and stop of hot melt discharge and the start and stop of hot air injection in Embodiment 1. FIG. 9 is a time chart showing the start and stop of hot melt discharge and the start and stop of hot air injection in Example 2. FIG. The figure which shows the liquid application apparatus by Example 3 of this invention. The figure which shows the conventional liquid application apparatus. The figure which shows the spiral application pattern adhering on a base material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid coating device 3 Spiral spray gun 5 Hot melt supply system 7 Valve body operating air supply system 9 Hot air supply system 11 Hot melt valve 13 Spiral nozzle 15 Hot melt discharge hole (liquid discharge hole)
17 Hot air injection holes (air injection holes)
19 spiral spray pattern 21 hot melt tank 23 hot melt inlet 25 hot melt chamber 27 outlet 29 valve seat 31 valve element 33 hot melt passage 33
35 Valve rod 37 Piston 39 Cylinder chamber 41 Air regulator 43 Electromagnetic valve 45 Compressed air inlet 47 Spring 49 Air regulator 50 Pressure switching device 51 Throttle valve 53 Electromagnetic valve 55 Hot air manifold 57 Hot air inlet 59 Hot air passage 61 Hot air chamber 63 Control device 65 Substrate 67 Spiral application pattern 67LE Tip 70 Control device 71 Passage 72 Passage 73 Spool valve type switching valve 81 Liquid application device W Application width P Application start position T1 Start time T2 Stop time T3 Start time Td Delay time HA Hook HB hook HC hook

Claims (4)

A method of applying a liquid to a substrate,
A first injection step of injecting pressurized air at a first pressure from a plurality of air injection holes;
A discharge step of discharging the liquid in a bead shape from the liquid discharge hole;
A second injection step of injecting pressurized air from the plurality of air injection holes to contact the liquid bead at a second pressure higher than the first pressure;
By starting the second injection step simultaneously with the start of the discharge step or after a predetermined time delay from the start of the discharge step, the pressurized air is brought into contact with the tip of the liquid bead at the first pressure, and then the first A method of applying a spiral coating pattern of a liquid on a substrate by bringing pressurized air into contact with a liquid bead at two pressures and drawing into a liquid fiber, and applying a swirling motion to the liquid fiber. . A liquid application device for applying a liquid to a substrate,
A liquid ejection hole;
A plurality of air injection holes which are provided around the liquid discharge holes and which inject pressurized air so as to substantially contact the outer periphery of the beads of the liquid discharged from the liquid discharge holes;
A valve body for starting and stopping the discharge of liquid from the liquid discharge hole;
A pressure switching device for switching the pressure of pressurized air injected from the plurality of air injection holes between a first pressure and a second pressure higher than the first pressure;
The pressure switching device is configured to inject pressurized air at a first pressure while stopping liquid discharge, and to inject pressurized air at a second pressure simultaneously with the start of liquid discharge or after a predetermined time delay from the start of liquid discharge. A liquid application apparatus including a control device for controlling. A method of manufacturing an absorbent article,
A transporting process for transporting the absorbent substrate in a predetermined direction;
A first injection step of injecting pressurized air at a first pressure from a plurality of air injection holes;
A discharge step of discharging the liquid in a bead shape from the liquid discharge hole;
A second injection step of injecting pressurized air from the plurality of air injection holes so as to contact the liquid bead at a second pressure higher than the first pressure;
By starting the second injection step simultaneously with the start of the discharge step or after a predetermined time delay from the start of the discharge step, the pressurized air is brought into contact with the tip of the liquid bead at the first pressure, and then the first At two pressures, pressurized air is brought into contact with the liquid bead and stretched to form a liquid fiber, and the liquid fiber is swirled to attach a liquid spiral coating pattern on the absorbent substrate being conveyed. And manufacturing the absorbent article.   The absorbent article manufactured by the manufacturing method of Claim 3.

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