JPH04100559A - Apparatus for forming, applying and circulating foamed adhesive - Google Patents

Abstract

PURPOSE:To uniformly and well apply a foamed adhesive by alternately transferring a mixture of an adhesive and air to the long groove of an inner rotary cylindrical body and that of an outer rotary cylindrical body and replacing the same by the rotation of the inner rotary cylindrical body to mix the same and applying the mixture to the upper surface of veneer. CONSTITUTION:A plurality of long grooves 10c, 11c divided at a plurality of places are provided to the outer surface of the inner rotary cylindrical body 10 and the inner surface of the outer fixed cylindrical body 11 of a foaming machine 5 and ring- shape closure parts 10d, 11d are provided to the divided places of the long grooves of both of them at a relational position shifted in the axial direction or opposed each other. An adhesive supply means 3 weighing an adhesive to supply the same to one end space of the foaming machine 5 and an air supply means 9 weighing air to supply the same thereto are provided. A size receiving hopper 18 receiving the uncoated adhesive among the foamed adhesive formed by the foaming machine 5 and flowing down in a definite amount from an extruder 17 is provided so as to hold the running path of veneer A along with the extruder 17. The adhesive is defoamed by a vacuum defoaming machine 20 to be returned to a tank 1.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to the production of a foam adhesive used in the production of plywood using a foam adhesive, application to the top surface of a veneer, defoaming of the foam adhesive, and adhesion. It relates to a series of devices for circulating agents.

[Conventional technology]

For example, as a means for forming a foam adhesive by mixing a liquid adhesive such as urea resin, melamine resin, or phenolic resin with a gas such as air, and applying it to the upper surface of each veneer composing plywood, there is a method described in US Pat. 3.895.984 discloses the production of plywood using a foam adhesive, and JP-A-1-164468 discloses an extrusion device for a foam adhesive.

[Problem to be solved by the invention]

The foaming machine disclosed in U.S. Pat. No. 3,895,984 has a plurality of recesses 92 and recesses 86 on the outer cylindrical surface of the inner rotor 82 and the inner cylindrical surface of the outer stator 80, respectively. By flowing adhesive and gas into the gap between the rotor 82 and the stator 80, each recess 86, 9
2, the adhesive and gas are stirred and mixed to produce a foamed adhesive. However, since the adhesive and gas mainly flow in the axial direction through the gap between the rotor 82 and the stator 80, sufficient stirring is required. There is a problem that a good foaming adhesive cannot be produced due to the lack of action, and also
The foam adhesive extrusion device disclosed in Japanese Patent No. 4468 is as follows:
A pair of impellers 27g and 27b connected to the foaming machine 7
is equipped with an impeller-type extruder 21 like a gear pump housed in a casing 28, and an intermittent drive device consisting of a motor 29 and an electromagnetic clutch brake 30 that operate the impeller intermittently. A fixed amount of foamed adhesive is applied to the regular veneer veneer that is transported directly below by extrusion coating operation intermittently at each cut in the transport direction.
A pair of impeller 27
It is very difficult to quantitatively control a, 27b,
There is a problem that changes in the foaming rate cause an increase or decrease in the amount of adhesive, and since the extruder 21 is operated intermittently, it is necessary to waste some adhesive at the front and rear ends of the regular veneer veneer in order to achieve uniform application. However, if you try to remove this, there is a problem of uneven coating.

[Means to solve the problem]

The outer cylindrical surface of the inner rotating cylindrical body and the inner cylindrical surface of the outer fixed cylindrical body of the foaming machine are each drilled with a plurality of long grooves divided at multiple points in the axial direction, and a ring-shaped blockage is formed at each divided point of both long grooves. Adhesive supply means is attached to the parts that are axially sliding or facing each other in relation to each other, and supplies a measured amount of adhesive to one end space of the foaming machine, and a gas that supplies a measured amount of gas such as air. A glue receiving hopper is provided below the extruder with a veneer running path in between, and is equipped with a supply means and receives uncoated foamed adhesive produced by the foaming machine and flowing down as a fixed amount by the extruder. The hopper is connected to a vacuum defoaming machine equipped with a stirring means, and an adhesive returning means is provided for feeding the adhesive defoamed by the vacuum defoaming machine to the glue tank.

[Effect]

A mixture of adhesive and gas is transferred between the long groove of the inner rotating cylinder and the outer fixing cylinder by a ring-shaped blockage attached to the dividing point of the long groove of the inner rotating cylinder and the outer fixing cylinder at a position that is offset or opposed to the axial direction. It alternates between the long grooves of the body, and the centrifugal force caused by the rotation of the inner rotating cylindrical body causes the exchange between the outer and outer long grooves, and this switching and the exchange caused by the rotation of the inner rotating cylindrical body ensure that the adhesive and gas are Since the supply of adhesive and gas to the foaming machine is controlled, the discharge volume of the extruder is regulated, and the glue installed below the extruder to receive the unapplied foamed adhesive is controlled. There is no need for intermittent discharge from the extruder due to the receiving hopper, and since a combination of vacuum and stirring is used to defoam the foamed adhesive, the bubbles easily burst due to the pressure difference between the inside and outside of the bubbles and the agitation, resulting in reliable defoaming. .

〔Example〕

The lower end of the glue tank 1 that stores liquid adhesive g such as urea resin, melamine resin, phenol resin, etc. is connected to the inlet side of a metering pump 3 such as a gear pump by a vibrator 2, and the outlet side of the metering pump 3 is used to supply adhesive. It is connected to one end of the foaming machine 5 by a tube 4. Further, one end of the foaming machine 5 is connected to a compressor 9 for gas such as air through a gas supply pipe 8 having a flow meter (digital mass flow meter) 6 and a flow rate adjustment valve 7 in the line.

As shown in FIGS. 2 to 4, the foaming machine 5 includes an inner rotating cylindrical body 10 located inwardly and an outer fixed cylindrical body 11 located outwardly.
The outer cylindrical surface of the inner rotating cylindrical body 10 and the outer fixed cylindrical body 1
A slight gap D (1, 5++n, etc.) is formed between the inner cylindrical surface of the inner rotary cylinder 10 and the outer fixed cylinder 11, and a space is formed between the side wall 10a and the side wall 11a at one end of the inner rotating cylinder 10 and the outer fixed cylinder 11. Sa,
A space sb is formed between the side wall 10b and the side wall 11b at the other end so as to communicate with the gap, and one space S
The adhesive supply pipe 4 and the gas supply pipe 8 are connected to the space a, and the discharge pipe 12 is connected to the other space sb. Furthermore, on the outer cylindrical surface of the inner rotating cylinder 10 and the inner cylindrical surface of the externally fixed cylinder 11, there are a plurality of long grooves 10c and long grooves 11C at appropriate intervals, and cuts at multiple locations in the axial direction of the cylinder. It is divided into two parts, and a part is drilled so that it communicates with the rain spaces Sa and Sb. In this case, it is desirable that the same number of long grooves 10c formed in the inner rotating cylindrical body 10 and long grooves 11c formed in the external fixing cylindrical body 11 be provided at opposing positions. And the long groove 10 of the inner rotating cylindrical body 10
C and the long groove 11C of the external fixing cylinder are each provided with a ring-shaped blocking part 10d such as an O-ring in the cut divided in the axial direction.
, a ring-shaped closing part 10d attached to the long groove 10c, and a ring-shaped closing part 11d attached to the long groove 11C.
As shown in FIG. 2, the two cylindrical bodies are attached at mutually shifted positions in the axial direction of the two cylindrical bodies. Further, although not shown in the drawings, the ring-shaped closing portion 10d and the ring-shaped closing portion 11d may be attached so as to be in opposing positions. The inner rotating cylinder 10 is rotated by a shaft 13 fixed to the side wall 10b, rotatably supported by a bearing 14, and by a drive mechanism 15 including a motor or the like in an appropriate direction and at an appropriate rotation speed. Cooling tube 1 provided on the outside of the externally fixed cylindrical body 11
Reference numeral 6 refers to cooling water taken in through the intake pipe 16a to cool the cylindrical portion of the externally fixed cylindrical body 11, and then taken out through the extraction pipe 16b to adjust the temperature of the mixture of adhesive g and gas.

The flow rate is measured by the metering pump 3 and the flow meter 6, and a predetermined flow rate of adhesive g and gas such as air are sent into the space Sa at one end of the foaming machine 5 by the adhesive supply pipe 4 and the gas supply pipe 8. is the space s at the other end from the space Sa
The adhesive g and gas that have entered the space Sa pass through the gap or directly into the long groove 10c drilled in the inner rotating cylinder 10 near the space Sa or the long groove drilled in the outer fixed cylinder 11. 11c, ring-shaped blockage 10d, ll
When the adhesive g and the gas that have entered the long groove 10c move in the direction of the space sb, they are blocked by the ring-shaped blockage part 10d and are attached to the long groove 11c facing each other through the gap. , the adhesive g and gas that have entered the long groove 11c move toward the space sb and close the ring-shaped blockage part 11.
d and moves to the opposing long groove 10c via a gap. Further, the adhesive g and gas that have entered the long groove 10c are directed toward the opposing long groove 11c due to the centrifugal force caused by the rotation of the cylindrical body, and the adhesive g and gas in the opposing long groove 11C are replaced through the gap. It will be done. The adhesive g and the gas move in the direction of the space Sd by repeating this transition and replacement, but the adhesive g and the gas are transferred and replaced from one long groove to the opposing long groove through the gap. When this is done, the rotation of the inner rotating cylindrical body 10 and the small gap provide a strong stirring effect, and the adhesive and gas are evenly mixed, and the gap reduces the size of air bubbles mixed into the adhesive. It is possible to produce a certain amount of foamed adhesive G in which bubbles of appropriate size are present in the adhesive. In addition, when attaching the ring-shaped closing portions 10d and lld to the respective long grooves 10c and 11C at opposing positions, the adhesive g and the gas have a stirring effect due to the rotation of the inner rotating cylinder 10 and the exchange between both long grooves. is applied, and the foaming rate decreases to some extent.

As the foaming machine 5, for example, an inner rotating cylindrical body 10 with a diameter of about 12 mm is used.
C1+m, a cylinder with a length of about 500cm, about 600r, p
, m, and feeds the urea resin adhesive g with an appropriate amount of foaming agent and hardening agent from the adhesive supply pipe 4 at a rate of about 10 g per minute. Space Sa
The compressed air of 5 Icg/CI' is supplied from the gas supply pipe 8 at approximately 40 times per minute! In the supplied test example, a suitable foamed adhesive G with a volume increased approximately five times and mixed with small air bubbles was obtained from the discharge pipe 12. The foamed adhesive G thus obtained is fed to the extruder 17 via the discharge pipe 12 as a substantially constant flow.

The falling type extruder 17 is commonly used for discharging this type of foamed adhesive G in a flowing manner, and is equipped with a number of nozzles 17a at the lower end, and a fixed amount of foamed adhesive G is linearly ejected from the nozzles 17a. It flows down as a stream, and is uniformly applied over the entire width of the upper surface of the veneer A, which is run by a belt conveyor or the like below. Below the flowing extruder 17,
A glue receiving hopper 18 is provided to receive the uncoated foam adhesive G flowing down from the extruder 17 across the running path of the veneer A and not being applied to the upper surface of the veneer A. The lower end of the glue receiving hopper 18 is connected to a vacuum defoamer 20 via a vibration line 19, a strainer 21 attached to the vibration line, and a stop valve 22.

The vacuum defoaming machine 20 is composed of a vacuum container 23 and a stirring means 24, and the stirring means 24 includes, for example, a rotating shaft 24a whose axis is substantially vertical and whose cross section is square, and a rotating shaft 24a that is positioned sequentially upward from the lower end of the rotating shaft 24a. A plurality of support rods 24b are attached by shifting the support rods 24b and changing the mounting surfaces, and a stirring plate 24c is attached to the attachment portion of each support rod 24b so as to be moderately inclined with respect to the horizontal plane, and the rotating shaft 24a is attached to the bearing 24d. Supported drive shaft 24
e, and the drive shaft 24e is connected to a drive mechanism 24 such as a motor.
The stirring plate 24c is rotated by rotating the stirring plate 24c.

The band heater 23a attached to the outside of the vacuum container 23 is for increasing the temperature of the foam adhesive G in the container, lowering the viscosity, and more effectively defoaming. Also, the vacuum container 23
A vibrator 25 is attached to the upper part and a vibrator 26 is attached to the lower part, and the vibrator 25 is connected to the vibe line 2 to the vacuum generator 27.
8 and connect to the vibe line 29 to the compressor 9,
The vibrator 26 returns to the vibrator 3 via the stop valve 30.
Connect to 1. A vacuum pressure gauge 32 and a stop valve 33 are attached to the vibration line 28, and the vibration line 29
A stop valve 34 and a pressure reducing valve 35 are attached to the valve.

Vacuum defoaming al! Defoaming of the foam adhesive G using No. 20 is carried out by the following procedure.

(1) Only the stop valve 33 is opened and the pressure inside the vacuum container 23 is appropriately reduced by the vacuum generator 27. (2) The stop valve 33 is closed and the stop valve 2
2 is opened, and an appropriate amount of the foamed adhesive G in the glue receiving hopper 18 is sucked into the vacuum container 23 by negative pressure.

(3) With only the stop valve 33 open, the inside of the vacuum container 23 is heated to -500 to -650+am by the vacuum generator 27.
) Vacuum to Ig.

(4) Close all the stop valves 22, 30, 33, and 34, drive the drive mechanism 24f, and operate the stirring means 24.

In this case, the bubbles in the foamed adhesive in the vacuum container 23 expand rapidly due to the reduced pressure in item (3) above, and the bubbles easily burst due to the synergistic effect of this expansion and the stirring by the stirring plate 24c of the stirring means 24. This ensures reliable and effective defoaming. Note that since the volume of the foamed adhesive G increases in the container due to the expansion of bubbles, it is desirable that the angle of inclination of the stirring plate 24C is set so that the stirring plate 24C pushes down the adhesive by rotation.

(5) Only the stop valve 34 is opened, and the inside of the vacuum container 23 is pressurized with compressed gas from the compressor 9.

(6) Next, the stop valve 30 is also opened, and the pressure of the compressor 9 is used to transfer the defoamed adhesive g in the vacuum container 23 to the adhesive tank 1 via the vibrator 26 and return vibrator 31.
to be sent to.

Foaming and defoaming test example: 100 parts of urea resin, 16 parts of wheat flour, 10 parts of water, 1 part of foaming agent
．． Adhesive g with a specific gravity of 0.94, which is a mixture of 2 parts, is added to the foaming machine 5.
As a result of foaming, a foamed adhesive G with a specific gravity of 0°193 is obtained, which is then heated to a vacuum degree of -60C1+ by an antifoaming machine 20.
As a result of stirring for about 30 seconds at mHg and a temperature of 30° C. in the vacuum container 23, a defoamed adhesive g having a specific gravity of 0.95 was obtained.

〔Effect of the invention〕

The foaming machine includes an inner rotating cylindrical body and an outer fixed cylindrical body with a small gap formed between the cylindrical surfaces, and a long groove divided in the axial direction is bored in the inner cylindrical surface and the outer cylindrical surface of each cylindrical body, A ring-shaped closing part is attached to each of the divided long grooves of the double cylinder body at a position shifted in the axial direction or a relative position facing each other, and adhesive and compressed gas are supplied from the space at one end of the double cylinder body. Since the structure is such that the mixture is metered and fed and the mixture is discharged from the space at the other end, the inflowing adhesive and gas move in the axial direction while shifting and/or switching from one long groove to the other long groove, This transfer and/or exchange and the rotation of the inner rotating cylinder provide a strong stirring action, and the adhesive and gas are reliably mixed to form a foamed adhesive. It is possible to create a foamed adhesive with a mixture of air bubbles of an appropriate size due to the limited size, and because the adhesive and gas are supplied to the foaming machine in a pre-measured amount, - a constant foaming rate can be obtained. Foamed adhesive is obtained, and the discharge amount (application amount) in the extruder is regulated, eliminating the difficulty of controlling the amount of foamed adhesive using the extruder as in the conventional method. Since the structure is equipped with a glue receiving hopper that receives the foamed adhesive to be applied, there is no need to intermittently discharge the extruder, and unlike conventional methods, there is no uneven coating or wasted adhesive due to intermittent discharge, and the foamed adhesive can be applied. The foamed adhesive is always uniformly and well applied to the top surface of the veneer, and the foamed adhesive received by the glue receiving hopper is defoamed by a vacuum defoaming machine equipped with a vacuum container and stirring means. The synergistic effect of expansion and agitation ensures reliable and good defoaming, and the defoamed adhesive can be reused.Furthermore, the compressor feeds the gas to the foaming machine and transfers the gas from the defoaming machine to the glue tank. The vacuum generator also serves to depressurize the vacuum container and transfer the foamed adhesive from the glue receiving hopper to the vacuum container, so the series of production, application, and circulation of this type of foamed adhesive is This has various effects such as simplifying the device and reducing equipment costs.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory diagram showing an outline of the generation, application, defoaming, and circulation of a foam adhesive, FIG. 2 is a sectional view of the foaming machine, and FIG. A cross-sectional view taken along line X-X in the figure,
FIG. 4 is a sectional view taken along line Y--Y in FIG. 2, and FIG. 5 is a side view of the vacuum foaming machine. DESCRIPTION OF SYMBOLS 1... Glue tank, 3... Metering pump, 5... Foaming machine, 9... Compressor 10... Inner rotating cylindrical body, 10c... Long groove, 10d... Ring-shaped blocking part, 1
1... External fixed cylindrical body, llc... Long groove, 1, 1 d
...Ring-shaped closure part, 17...Flux type extruder, 18
... Glue receiving hopper 20 ... Vacuum defoamer, 23
... Vacuum container, 24... Stirring means, 24c... Stirring plate, 27... Vacuum generator, A... Single plate, D...
Gap, G... foam adhesive, g... adhesive, Sa, Sb
···space. Tao male stem 3f! J. Form of correction for procedures (method) % formula %: Display of the case 1990 Patent Application No. 215208 Name of the invention Foaming adhesive generation coating circulation device Person making the correction Relationship to the case Patent applicant postal code 223 Address: 662 Nippa-cho, Kohoku-ku, Yokohama Representative: Takao Minami 4゜Date of amendment order

Claims (1)

[Claims] An inner rotating cylindrical body and an outer fixed cylindrical body are provided, each having a slight gap between their cylindrical surfaces and an appropriate space at both ends. A plurality of long grooves divided into a plurality of cylindrical positions in the axial direction are bored at appropriate intervals on the inner cylindrical surface, and ring-shaped closing parts are arranged at the dividing points of both long grooves so as to be offset from each other or opposite to each other in the axial direction. A foaming machine attached to a related position, an adhesive supply means consisting of a metering pump, etc., which meters and supplies liquid adhesive from a glue tank to one end space of the foaming machine, and a compressed gas such as air. A gas supply means consisting of a compressor or the like is connected to the other end space of the foaming machine, and a fixed amount of foam adhesive is applied in a line over the entire width of the veneer being conveyed on the track. A falling type extruder that causes the flow to flow down, a glue receiving popper that receives the unapplied foamed adhesive placed below the flowing extruder across a veneer track, a vacuum container, a stirring means, and a vacuum container that reduces the pressure inside the vacuum container. and a vacuum generator that sucks foamed adhesive from the glue receiving popper into a vacuum container, and a pipeline connecting the vacuum container of the vacuum defoamer to the compressor and the glue tank. 1. A foamed adhesive production and application circulation device comprising: an adhesive returning means;