JP2002079165A - Device and method for coating with liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform good finished coating to have a smooth surface on a woody material to be coated, which has unevenness, crack, worm-eaten spots on the surface. SOLUTION: A coating device is composed of a squeeze type coating quantity control member 1, in which a pushing member for transporting a plate like material 3 to be coated such as a plywood and a pressurizing device are installed, a surrounding member 2 for forming an adequate coating liquid pond between the control member 1 and the surrounding member 2, a coating liquid supply means 5 for supplying the coating liquid 4 to the coating liquid pond formed by the control member 1 and the surrounding member 2 and a coating liquid drying means, and one surface 2a of the surrounding member 2 is arranged in the vicinity of the control member 1 and on the upstream side in the transporting direction of the material 3 to be coated. The coating method is performed by using this device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a coating method for coating a coating liquid on a plate-like object such as plywood.

[0002]

2. Description of the Related Art Conventionally, a coating liquid such as an adhesive or a paint has been applied to the surface of plywood, veneer, Japanese paper, etc., and a roll coater, a flow coater, a natural reverse coater, a sprayer, etc. Coating devices such as a coater and a knife coater are used.

[0003]

However, when the coating apparatus according to the prior art described above is used for a curable coating liquid such as a dry type or a curable liquid, for example, a roll coater diffuses the reaction heat of the liquid pool, Heat cannot be dissipated and hardens on the roll. The flow coater cannot fill the unevenness of the object to be coated. The natural reverse coater warps and twists the object to be coated, so that smooth coating cannot be performed. The spray coater has various drawbacks, such as inability to fill a defective portion on the surface, resulting in a poor paint yield, and a knife coater having difficulty in controlling the amount of coating, and has not always been satisfactory.

On the other hand, recently, due to the log condition of the wooden board for formwork, the surface of the material has deteriorated, and the degree of irregularities and cracks has been remarkable.
In painting, defective parts must be completely repaired, and for that purpose the coating must be thickened. Therefore, in the urethane-based paints conventionally used, foaming occurs,
Due to whitening and reduced product value, it is changing to a quick-curing epoxy coating, but as described above, the current coating equipment cannot sufficiently cope with it, and the knife coater has good filling properties and a thick coat of roll coater. The development of a new coating apparatus which has a feeling and can put in a fast-curing paint on a first-in first-out basis is urgently required. SUMMARY OF THE INVENTION An object of the present invention is to improve the drawbacks of the conventional apparatus and to provide a coating apparatus suitable for coating a wooden formwork plate.

[0005]

The inventor of the present invention has made intensive studies to achieve this object, and as a result, a coating apparatus based on a special squeeze coater has a good filling property of the uneven portion and a coating film. The present inventors have found that it is possible to control thick coating and the like, and also to be able to handle warpage and twist, to be easy to handle, and to be able to perform first-in first-out even with a fast-curing and high-heat-generating paint. That is, according to the present invention, a pressing member for conveying a plate-shaped object to be coated such as a plywood, a squeeze type coating amount control member provided with a pressurizing device, and an appropriate coating liquid reservoir are formed between the pressing member and the control member. And a coating liquid supply unit for supplying a coating liquid to the coating liquid reservoir formed by the control member and the surrounding member, and a coating liquid drying unit. A liquid coating apparatus, which is installed in the vicinity and on the upstream side in the transport direction of an object to be coated.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pushing member is installed in front of a squeeze type coating amount control member, that is, upstream of a conveying direction in a conveying process of an object to be coated (wooden board), and is provided with a coating amount control member, a conveying belt and a conveying roller. To push the object to be coated and transport the object to be coated. The pushing speed is synchronized with the conveying speed of the object to be coated, or the speed is made faster so that the object to be coated (wood board) is continuously fed to the coating amount control member so that the objects to be coated are continuously butted. Is what you do.

[0007] The squeeze-type coating amount control member of the present invention is provided with a pressing device because it controls the coating amount so as to be in contact with the surface of the object to be coated in a constant pressurized state. The pressurizing device is installed above the coating amount control member, at the rear side (downstream side in the transport direction) of the workpiece in the transport direction, and at an angle of 5 to 45 with respect to the vertical direction of the workpiece surface. It is installed so that pressure can be applied to the object. By adjusting the contact width of the coating amount control member with respect to the surface of the plate-shaped object to be coated by the pressurizing device, uniform application of the coating liquid to the plate-shaped object can be facilitated.

[0008] The pressurizing means of the pressurizing device may be any method such as a hydraulic cylinder or a spring, but a pneumatic cylinder is preferable from the viewpoint of easy pressure control, and the diameter is 50 m.
3-5 pneumatic cylinders with a pressure of 0.1 m.
1-6 kg / cm ² , preferably 0.1-4.0 kg / cm ²
cm ² . When the pressure is out of the range, it is difficult to apply an appropriate amount of the coating liquid, and defects such as blurring and uneven coating may occur. When the pressing direction of the application amount control member is out of the range of 5 to 45 degrees with respect to the vertical direction, the application object slips or the application object sent to the application amount control member becomes intermittent. It interferes with normal painting work.

The squeeze type coating amount control member may be a roll or a roll, or a plate such as a rubber belt or a plastic having a curved surface in contact with the substrate. The surface of the coating amount control member that is in contact with the object to be coated has a hardness of 30 to 90 degrees, preferably 40 to 6, as measured by a C-type rubber hardness meter.
It is composed of 0 degree members. Usually, a roll made of a material such as plastic such as synthetic rubber and urethane rubber is used. If the hardness is 30 degrees or less, the generation of streaks increases due to the bite of a cured product of the paint or dust on the surface of the object to be coated. . Among them, the use of a roll having a hardness in the range of 40 to 60 degrees makes it possible to improve the filling property of the coating material, to cope with twisting and warping of the object to be coated, and to easily adjust the thickness of the coating film.

The angle of entry of the object to be applied to the roll or the roll-shaped object is 4 ° with respect to the vertical direction of the surface of the plate-shaped object to be coated.
It is set to be 5 to 85 degrees. Here, the entry angle refers to a contact angle between the surface of the object to be coated and a coating amount control surface of a roll or a roll-shaped object (coating amount control member) in contact with the surface. If the angle of entry of the object to be applied to the coating amount control member is 85 degrees or more, a streak occurs due to liquid leakage or dust, and the amount of coating liquid that stays on the upstream side (front surface) of the coating amount control member increases. The solution is easily gelled, and when the temperature is 45 degrees or less, the rotation of the coating solution in front of the coating amount control member is intense, and entrainment bubbles increase. The contact width between the coating amount control member and the object to be coated is 5 to 50 mm in the length in the transport direction of the object to be coated.
When the thickness is 5 mm or less, the filling limit of the coating solution is exceeded and uniform application cannot be performed. When the thickness is 50 mm or more, thick coating is not preferable because stripes are frequently generated and the commercial value is reduced.

The enclosing member has one surface disposed near the coating amount control member and within 300 mm upstream in the conveying direction of the object to be coated, and the coating liquid staying in the direction parallel and perpendicular to the coating amount control member. Is a device for enclosing the stagnant liquid in a box shape together with the squeeze roll, and is a device accompanying the coating amount control member (for example, a squeeze roll) constituted by a plate arranged to hold the coating liquid. It has functions such as preventing leakage to the outside, preventing rotation of retained paint (prevention of entrained bubbles), reducing the amount of liquid pool and heat generation (extending the usable time), and promoting the first-in first-out of the coating liquid. This is for suppressing the cured product to the limit and maintaining stable coating.

In order to adjust the contact width between the coating amount control member and the object to be coated, in addition to the pressurizing device, it is installed below a plate-shaped object to be coated in contact with the application amount controlling member, By providing a coating amount stabilizing member having a function of absorbing and relaxing the pressure of the member and adjusting the contact width, the stabilization of the coating operation can be improved. The application amount stabilizing member is a member that presses the object to be applied to the application amount control member from the lower surface of the object, and is urged from the back surface of the object by a spring, a hydraulic cylinder, or the like. It is preferable to provide it below the application amount control member. However, in order to apply a uniform force to the back surface of the work, it may be provided at both ends in the transport direction of the work or at any position. The member in contact with the back surface of the object may be a roller, but is preferably a plate-shaped member.

[0013] The coated object is subjected to a booth adjusted at room temperature or at an appropriate temperature and humidity to correct the fluctuation of the coating solution after squeezing before the drying process and to thoroughly level the coating solution. (Applying and smoothing means for the coating solution). In the coating apparatus of the present invention, the paint to be used is not particularly limited. However, in consideration of the above-described circumstances of the wooden board for formwork, a paint having a gelation time at 60 ° C. within a range of 2 to 7 minutes, particularly a feature. The viscosity is 20-200dPa.
s / 25 ° C. epoxy compound and viscosity of 0.5 to 30 dP
A paint having a solvent content of 5% or less, which comprises an active hydrogen compound having a value of a · s / 25 ° C. or less, and which satisfies the formula (1) representing the dryness to the touch of a coating film is preferable. log (m) = − 0.009 (T) + k (1) where (T) is the drying temperature (° C.) of the coating film, and (m) is the time required for touch drying (minutes) k is 1.4 to A value of 2.0 is shown.
It is not easy to judge the workability, productivity, finish of the coating film as a product at the manufacturing site, but from the drying temperature and the touch drying time at the temperature, the formula (1) is used. The value can be easily determined by determining the k value based on the calculated value and determining whether the k value is within the above range. in this case,
The touch drying time is 30 to 30 minutes.
It refers to the time until the coating is evenly applied to a film thickness of 70 μm and the coating film remains behind even when touched with a finger or the like.

The paint is preferably a liquid in consideration of workability at a temperature normally used, and particularly preferably has a viscosity of 20 to 20.
0 dPa · s / 25 ° C. epoxy compound and viscosity 0.5
A paint comprising an active hydrogen-containing compound at a temperature of 30 dPa · s / 25 ° C. is preferred. Considering the working environment and occupational hygiene, a paint having a solvent content of 5% by weight or less is desirable. As the epoxy compound, any compound having the above properties can be used. For example, bisphenol A diglycidyl ether,
Bisphenol F diglycidyl ether, phenol novolak polyglycidyl ether, cresol novolak polyglycidyl ether, halogenated bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, tetrafunctional polyglycidylamine, aliphatic polyglycidyl ether, aromatic polyglycidyl Epoxy resins having one or more epoxy groups in the molecule, such as ether, aliphatic glycidyl ether and aromatic glycidyl ether, may be used. These epoxy compounds can be used alone or in combination of two or more.

The active hydrogen-containing compound includes active hydrogen such as aromatic amines, aliphatic amines, cycloaliphatic amines, polyamidoamines, mercaptans, alcohols, organic acids and their anhydrides, and complex compounds of Lewis acids and amines. (-
_{OH, -SH, -NH 2, =} NH, -COOH) can be the mentioned compounds containing in the molecule, these can be used in conjunction least one or two. Also,
If necessary, an organic base such as a tertiary amine, an inorganic base such as potassium hydroxide, or thiourea can be used as a catalyst. Further, a curing accelerator such as bisphenol A may be used.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. 1 and 2 are views showing the relationship between the squeeze-type application amount control member and the surrounding member. FIG. 1 is a side sectional view, and FIG. 2 is a top view.
As shown in the drawing, one surface (front plate 2a) of the surrounding member 2 is located near the roll 1 on the upstream side in the transport direction of the plate-shaped workpiece 3 with respect to the roll 1 as the coating amount control member. The coating liquid 4 supplied between the roll 1 and the front plate 2a is always held in an appropriate amount. The surrounding member 2 is shown in FIG.
As shown in FIG. 3, side plates 2b and 2b are provided on both sides of the roll 1 so as to surround the roll 1, and the coating liquid 4 is prevented from flowing out from both ends of the roll 1 together with the front plate 2a, and the liquid is applied to the front of the roll. A reservoir is formed, and first-in first-out application of a coating liquid is enabled. Reference numeral 4a denotes a coating film applied on the surface of the object 3 to be coated. Front plate 2a and both side plates 2b, 2 of surrounding member 2
b may be formed integrally, or may be separately supported to form the surrounding member 2. The surrounding member may be formed of a material such as fluororesin or polyethylene, from which the adhered paint can be easily peeled off, or may be a material that is easy to clean, for example, a metal such as stainless steel. In FIG. 1, reference numeral 5 denotes a coating liquid supply nozzle.

FIG. 3 shows another example of the squeeze type coating amount control member. In the present invention, since the coating amount control member is of a squeeze type, even in the case of the roll 1 shown in FIGS. For this reason, only a portion (contacting member) having a moderately curved surface may be used as a handling (ironing) member only in a portion in contact with the surface of the object to be coated 3. FIG. 3 shows a squeeze member 1 a in which both side surfaces of a roll are cut off. It is an example. As compared with the case of the roll 1 in FIG. 1, the front plate 2a of the surrounding member 2 can be made closer to the roll side, and the amount of the coating liquid 4 stored can be reduced.

In the case of squeeze coating, since the coating thickness is determined by the degree of pressing of the coating amount control member in contact with the surface of the object, the coating amount control member is pressurized. FIG. 4 is a diagram illustrating an example of a method of pressing the application amount control member. The application amount control member may be pressurized only by pressurizing the roll 1 serving as the control member, but in the case of this example, an example in which the pressurization is also applied from the lower surface of the work 3 is shown. The pressure of the roll 1 on the surface of the substrate is
This is performed by a pressurizing device 6 such as an air cylinder, a hydraulic cylinder, or a spring. An air cylinder is preferable in terms of ease of control, and the roll is uniformly pressed by two or three cylinders and pressed against the surface of the article 3 to be coated. In the drawing, reference numeral 7 denotes a support member for pressing the object 3 against the roll 1 from the lower surface. The support member 7 is a flat plate having a smooth surface because the object 3 is a plate-like material such as a wooden board. Then, a pressure means such as an air cylinder, a hydraulic cylinder, or a spring is provided at a lower portion. In FIG. 7, the spring 8
Here is an example using. The support member 7 has an application amount stabilizing action together with the application amount control member. The workpiece 3 is sequentially fed between the roll 1 and the support member 7 by a feed roll (push member) 9 and applied.

FIG. 5 shows still another example of the coating amount control member. The application amount control member 1b in the case of the present example has a shaft 10
A plate-like member made of hard rubber, plastic or metal, which is held by the pressurizing device 6 and shows a moderate bending when pressed. FIG. 6 shows an example of a coating amount control member including the endless belt 1c. The squeeze-type coating amount control member of the present invention controls the coating amount by contacting the tip with the surface of the object to be coated, but depending on the coating liquid, solidified paint scum accumulates at the tip of the coating amount control member and controls the coating amount correctly. Some things will not be possible. Therefore, a short plate-shaped control member c is connected in an endless belt shape as shown in the figure, and is moved at regular intervals so that a new control member c is always in contact with the workpiece 3. In the figure, the endless belt 1c is configured to rotate in a circular shape.
It may be circular, elliptical, or square. The direction of rotation of the endless belt may be either direction. However, when the endless belt is rotated in a direction opposite to the conveying direction of the object to be coated, the filling property and the coating property of the coating liquid are improved. Further, when the washing step and the drying step of the belt are provided above the endless belt, the finish of the coated surface is further improved.

FIG. 7 is a diagram for explaining the entry angle of the article to be coated and the like. The line indicated by Y in FIG. 7 is a vertical line with respect to the surface of the plate-shaped object to be coated, and X indicates a line along the surface of the object to be coated. A point at which the coating amount control surface of the roll or the roll-shaped material (coating amount control member 1) is in contact with the surface of the workpiece is defined as a base point O.
A line along the inclined coating amount control surface is indicated by an extension line y. The “entrance angle” referred to in the present invention indicates an angle ΔYOy = θ ₁ between the vertical line Y and the extension line y. In the case of the present invention, ΔY
When the relationship between the coating amount control member 1 and the object 3 is set such that Oy = 45 to 85 °, good results can be obtained. Also shows the direction of the pressure applied by the pressure device 6 with respect to the coating amount control member 1 at theta _3. Along the line z which is inclined at an angle of theta ₃ with respect to the vertical line Y as shown in Fig application amount control member 1
Press. The angle θ ₃ = ∠YOz = 5 to 45 °. In the figure, L indicates the contact width between the coating amount control member 1 and the article 3 to be coated. The contact width L is adjusted mainly by the pressing force applied to the application amount control member 1.

FIG. 8 is a diagram showing all the steps of the present invention. The workpiece 3 placed on the workpiece supply device 11 at the right end in the figure is sequentially sent to the coating amount control member 1 by the pushing member 9 and is coated with a predetermined coating liquid. The object (coating plate 3a) to which the coating liquid has been applied is sent to a coating liquid habituation / smoothing chamber 12 and then dried by a coating liquid drying device 13, and the coating plate 3a is sequentially sent to a product deposition device 14. Stacked and sent to subsequent processing as a product. In the above, the adaptation / smoothing chamber 12 is a room for holding the applied coating liquid in a flat state for several seconds to several tens of seconds so that the applied coating liquid is adapted to the surface of the object to be coated. Is not sprayed. As the drying device 13, a normal drying means using hot air, infrared rays, electric heat or the like is used. In the case where the paint or object to be thermally degraded is a plate-like material such as softwood plywood, which warps at a high temperature, a cooling zone may be provided between the drying device 13 and the product deposition device 14.

[0022]

The present invention has a thickness like a wooden board,
A coating having a thickness of 50 μm or more can be applied to an object to be coated having irregularities such as knots and insect bites on a surface by a single application, and a coated product having a smooth surface and a uniform film thickness can be obtained. Further, in applying the coating liquid, since the coating liquid can be applied in a first-in first-out manner, the dried or cured product of the coating liquid does not adhere to a roll or a roll-shaped coating amount control member, and the workability and productivity are good. There are various advantages such as.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a coating apparatus of the present invention.

FIG. 2 is a top view illustrating an example of the coating apparatus of the present invention.

FIG. 3 is a side view showing another example of the coating apparatus of the present invention.

FIG. 4 is a side view showing an example of a pressurizing device for an application amount control member of the present invention.

FIG. 5 is a side view showing another example of the coating amount control member of the present invention.

FIG. 6 is a side view showing another example of the coating amount control member of the present invention.

FIG. 7 is a side view of an application amount control member for describing an approach angle according to the present invention.

FIG. 8 is a schematic view showing all steps of the coating apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roll (coating amount control member) 2 Surrounding member 3 Coating object 4 Coating liquid 5 Coating liquid supply nozzle 6 Pressure device

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4D075 AC16 AC53 AC54 AC72 AC74 AC92 AC93 AC95 AC96 BB05Y BB24Z CA48 DA06 DB22 DC03 EA09 EB33 EB45 4F040 AA02 AB04 AC01 BA35 DB12 DB30 4F042 AA02 DD07 DD09 DD17 DD18 DD21 DD27 DD45

Claims (10)

[Claims] 1. A squeeze-type application amount control member provided with a pressing device for conveying a plate-like object to be coated such as a plywood, and a pressurizing device, and an appropriate application liquid reservoir is formed between the control member and the squeeze type application amount control member. An enclosing member for supplying an application liquid to an application liquid reservoir formed by the control member and the enclosing member;
And a coating liquid drying means, and one surface of the surrounding member is installed near the control member and upstream in the transport direction of the object to be coated. 2. A pressurizing device, which is located above the squeeze-type application amount control member and on the downstream side in the transport direction, and is 5 mm apart from the vertical direction.
The coating amount control member is installed so as to be able to press against the surface of the object to be coated at an angle of up to 45, and the contact width of the application amount control member with the surface of the object to be coated can be adjusted. The liquid coating apparatus according to claim 1. 3. A contact width between the control member and the surface of the object to be coated, which is provided below the plate-shaped object to be coated by the application amount control member and absorbs and relaxes the pressure of the application amount control member. The liquid application apparatus according to claim 1, further comprising a coating amount stabilizing member having a function of performing the operation. 4. A squeeze-type coating amount control member comprising a roll or a roll having a hardness of 30 to 90 degrees measured by a C-type rubber hardness meter, and an angle of entry of a plate-like coating object with respect to the roll or the roll. The liquid coating apparatus according to any one of claims 1 to 3, wherein the angle is 45 to 85 with respect to the vertical direction of the surface of the plate-shaped object to be coated. 5. The liquid coating according to claim 1, wherein a contact width between the coating amount control member and the object to be coated in the object conveying direction is 5 to 50 mm. apparatus. 6. An enclosing member, one surface of which is placed within 300 mm upstream in the conveying direction of the object to be coated in the vicinity of the coating amount control member, and arranged in a direction parallel and at a right angle to the coating amount control member. The coating liquid according to any one of claims 1 to 5, wherein the coating liquid is configured to be stored and held in an interior surrounded by the plate and the coating amount control member. Liquid application equipment. 7. A stationary coating liquid in the surrounding member, which is 0.2 to 10 times the coating amount to be applied per minute to the plate-like coating object,
The liquid coating apparatus according to claim 6, wherein the liquid coating apparatus is held. 8. A method for coating a liquid, comprising using the coating apparatus according to claim 1. 9. The method for coating a liquid according to claim 8, wherein a coating material having a gel time at 60 ° C. within a range of 2 to 7 minutes is used. 10. The coating material to be applied has a viscosity of 20 to 200.
dPa · s / 25 ° C. epoxy compound and viscosity of 0.5 to
A paint containing 30 dPa · s / 25 ° C. or less of an active hydrogen compound and having a solvent content of 5% or less, wherein K is 1.4 to 2.0 in the formula (1) representing the dryness to touch of the coating film. The method for coating a liquid according to claim 8, wherein the coating is: log (m) =-0.009T + K (1) Here, (T) indicates the drying temperature (° C.) of the coating film, and (m) indicates the time (minute) required for touch drying.