JPH02102764A - Method and equipment for coating - Google Patents

Abstract

PURPOSE:To form a uniformly coated face by blowing coating liquid on the surface of a sheetlike material in an atomizing state through an atomizing nozzle and smoothing the upper layer part of the coated layer with an air knife and regulating thickness of the coated layer to final coated thickness. CONSTITUTION:A plurality of atomizing nozzles 7 are arranged oppositely to the surface of a sheetlike material 1 in the width direction thereof. A coated layer is formed by blowing coating liquid 9 of 1-2 times of applying amount necessary for formation of the coated layer having final coated thickness on the surface of the sheetlike material 1 in an atomizing state through the nozzles 7. Then thickness of the coated layer is regulated to the final coated thickness by smoothing the upper layer part of the coated layer with an air knife 4 provided oppositely to the surface of the sheetlike material 1 in the downstream side from the position of the nozzles 7 for the running direction of the material 1. As a result, uniformly coated film free from deterioration of quality due to mixing of refuse, etc., can be formed without impairing the surface of the sheetlike material in noncontact.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to improvements in a coating method and apparatus for continuously and uniformly applying a coating liquid to a sheet-like object traveling in a predetermined direction with a maximum coating thickness of n. .

(Prior art and its problems) Conventionally, a method and apparatus for uniformly coating the surface of a sheet-like object with a coating liquid to the final coating thickness include a method using an air knife coater (for example, Japanese Patent Publication No. 61-39867). , Japanese Patent Publication No. 62-31625, etc.) and those using a spray nozzle (for example, Japanese Patent Publication No. 57-235).
No. 46, actual 1m No. 59-70763, etc.).

Among these, those using an air knife coater require a coating layer (hereinafter referred to as "essential coating layer") necessary to form a coating layer of the final coating thickness on the surface of a sheet-like object in advance by coating means such as a fountain or an applicator roll. ) After coating the surface of the sheet-like object with an excess coating liquid, the excess coating liquid is blown off by air blown from an air knife to adjust the thickness of the coating layer to the final coating thickness. In this method, the coating thickness can be adjusted by using an air needle that blows air from an air knife.

Further, the method using a spray nozzle is a method in which the spray nozzle turns the coating liquid into particles (spray i) and applies a predetermined amount onto the surface of the sheet-like object to obtain a predetermined coating thickness. Also,
In some cases, it may be applied in several layers.

All of these methods have the advantage of being able to coat the surface of the sheet with the coating liquid without contacting the sheet, so there is less damage to the surface of the sheet and the coating can be done at high speed. .

However, both methods have the following problems.

In the air knife coater, the excess coating liquid that is blown off by the air knife is circulated and reused, so there is a risk of dust getting mixed in at the position where the excess coating liquid is blown off or in the pan that receives the excess coating liquid that has been blown off. Therefore, there is a problem that the quality of the coating surface deteriorates.

Here, in order to solve this problem, the excessive amount of the coating liquid supplied to the surface of the sheet-like object by a coating means such as a fountain is reduced as much as possible. It is conceivable to bring δ) closer to the essential coating layer. However, if the amount of coating liquid supplied is reduced, uneven coating occurs in the width direction, making it impossible to coat with a uniform thickness. Therefore, it is still necessary to supply more than 5 times as much Φ liquid as the required coating layer. There is a b limit to quantity reduction.

On the other hand, the latter method using a spray nozzle turns the coating liquid into particles and fills it! Since the amount corresponding to the coating thickness is applied to the surface of the sheet-like object, the above-mentioned problems (contamination of dust, etc. into the coating liquid) do not occur, but the coated surface may be prone to the accumulation of particulate coating liquid. Since the shape of the coating liquid is reflected on the surface of the coating, there is a problem that a uniform coating surface cannot be obtained, that is, unevenness occurs on the coating surface corresponding to the size of the particles.

(Object of the invention) The present invention has been made to solve the above problems,
An object of the present invention is to provide a coating method and an apparatus thereof capable of forming a uniform film coating without contacting the surface of a sheet-like object without damaging it and without degrading the quality due to dirt or other contaminants.

(Means for Achieving the Object) The invention according to claim 1 provides a coating method for uniformly applying a coating liquid to a final coating thickness on a sheet-like object traveling in a predetermined direction continuously. In order to form a coating layer having the final coating thickness on the surface of the sheet-like object from a plurality of spray nozzles arranged in the width direction facing the surface of the sheet-like object toward the surface of the sheet-like object. The coating liquid is sprayed in an amount of 1 to 2 times the required coating m to form a coating layer. An air knife placed facing the object surface allows
The upper layer of the coating layer was scraped to adjust the coating thickness of the coating layer to the maximum coating thickness of 1yJ.

Further, the invention according to claim 2 provides a coating device that continuously and uniformly applies a coating liquid to a final coating thickness on a sheet-like object traveling in a predetermined direction. A plurality of spray nozzles for spraying a liquid at a spray angle α are arranged at a pitch L in the width direction facing the surface of the sheet-like object, and a distance 111ta between the surface of the sheet-like object and the spray nozzles faces each other. a≧L/2tan (
a/2), from the spray nozzle toward the surface of the sheet-like object, 1 to 1 of the coating layers necessary for forming a coating layer of the maximum coating thickness on the surface of the sheet-like object. a coating means for forming a coating layer by spraying twice as much of the coating liquid in the form of a spray; An air knife is provided to face the coating layer and scrape the upper N portion of the coating layer to adjust the thickness of the coating layer to the final coating thickness.

(Example) FIG. 1 is a schematic configuration diagram showing an embodiment of a coating apparatus according to the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a top view of FIG. It is a picture of 'l arrow congratulations. As shown in FIG. 1, the coating apparatus includes a conveying means (not shown) for moving a sheet-like material 1 in a predetermined direction, and a coating means 2.
, a booth 3, an air knife 4, a pan 5, and a backup roller 6.

The coating means 2 is provided upstream of the backup 1-ra 6 with respect to the traveling direction of the sheet-like material 1, and is composed of a spray nozzle 7 and a coating liquid supply pipe 8. That is, the spray nozzles 7 are arranged at a pitch Llt! along the width direction of the sheet-like material 1. A coating liquid 9 is screwed into the liquid supply pipe 8 and is supplied from a pump (not shown) via the coating liquid supply pipe 8.
The spray 10 is applied onto the surface of the sheet-like material 1. The coating fluid supply pipe 8 is supported at both ends thereof with respect to the base 11 so as to be able to rise and fall and rotate freely, and is movable in the vertical direction and around the rotation axis N by means of a pipe driving means (not shown). It is configured to be rotatable. Here, as can be easily seen from FIG. 3, the spray nozzles 7 normally have a spray angle α, but when the spray nozzles 7 are arranged at a pitch L in the width direction of the sheet-like material 1, the spray nozzles 7 If the facing distance 11ia between the sheet material 7 and the sheet material 1 is a<1/2jan (cz/2) . Set so that 1! separation a opposite to L satisfies a≧L/2(an(cr/2)−(2), and the boundaries of spray n 10 of adjacent spray nozzles 7 coincide, The pitch of the spray nozzles 7 should be such that the spray 10 emitted from one spray nozzle 7 toward the surface of the sheet material 1 every φ time. q, total sum of coating liquid 9 supplied from the pump to each spray nozzle 7 per medium time ff1
It is determined by substituting Q and the width S of the coating surface to be coated on the surface of the sheet-like article 1 into the following equation.

L=S/(Q/Q)=S(1/Q...(3)
Furthermore, when the arrangement pitch L obtained from equation (3) is narrower than the individual width of the spray nozzle 7, it is physically impossible to arrange them in a straight line in the width direction of the sheet-like material 1, as described above. However, in such a case, it is sufficient to provide a plurality of coating liquid supply pipes 8 and arrange them in a staggered manner so that the arrangement pitch L can be ensured.

As shown in FIGS. 2 and 3, the air knife 4 is supported at both ends thereof with respect to the base 11 so as to be movable up and down and back and forth, and is moved downward and downward by a knife moving means (not shown). It is configured to be movable in the front-back direction.

Further, a duct 12 is connected to both ends of the air knife 4, and air is supplied to the air knife 4 from a blower (not shown) through the duct 12, and air is also supplied from the tip 4a of the air knife 4 to the sheet-like material 1. It is designed to be sprayed onto a surface.

The air knife 4 is provided with an adjustment bolt 13, and the degree of opening and closing of the tip 4a of the air knife 4 is controlled by these adjustment bolts 1-13.

Next, the operation of the coating apparatus configured as described above will be explained. First, the resheet-like material 1 is
is fed in a predetermined direction at a substantially constant speed T:11, and at the same time, a coating liquid in an amount equal to or greater than the required coating area is sprayed onto the surface of the sheet-like material 1 from the coating means 2 along the width direction of the sheet-like material 1. to form a coating layer on the surface of the sheet-like material 1. Next, air is blown with the air knife 4 toward the upper layer of the coating layer on the surface of the sheet-like article 1 thus formed, to scrape off the upper part of the coating layer. In this case, the air blowing speed from the air knife 4 is adjusted as follows.

That is, when there is excess coating liquid 14 (FIG. 1) on the coating layer, the excess coating liquid 14 (FIG. 1) is removed by blowing air, and the surface of the coating layer is smoothed and flattened. When the layer 4 sprayed onto the surface of the sheet-like material 1 by the coating means 2 is an essential coating layer, in other words, when there is no excess coating liquid 14 in the coating layer 15, the coating liquid is 14 is not removed, but is simply adjusted to a value such that the surface of the coating layer is smoothed and flattened. In this way, a uniform coating film having a final coating thickness is formed. The removed coating liquid 14 is collected by the pan 5 and then supplied to the coating means 2 from a circulation means (not shown) to be reused. In addition, when forming a coating layer on the coating means 2, all the spray 10
does not adhere to the sheet-like material 1, and some of it is not attached and scatters in all directions, but after this scattered spray is collected by the booth 3, it is sent to the circulation means (not shown) in the same way as above. It is supplied to the coating means 2 and reused.

As described above, after the coating layer is formed by the coating means 2, the surface of the coating layer is scraped and flattened by the air knife 4, so that the surface of the sheet-like article 1 is not damaged without contact. , a uniform coating can be formed. Furthermore, when forming the coating layer, since the coating means 2 first coats the Zunawara coating liquid 9 onto the surface of the wetted sheet-like material 1 which has been sprayed wJ10, the excess coating liquid 14 is suspended. It is possible to minimize the amount of dust and the like that gets mixed in when the surplus coating liquid 14 is reused.

As a result of actually conducting various quality evaluation tests, we found that coating means 2
When the amount of coating sprayed onto the surface of the sheet-like material 1 is about 1 to 2 times the required coating layer, almost no deterioration in the quality of the coating due to the contamination of dust is observed.
It was found that products of excellent quality were obtained.

An example of the experimental results is shown below. In other words,
A polynisder film having a width of 1 TrL and a thickness of 30 μm is prepared as the sheet-like material 1, and is run in a predetermined direction at a speed of 200 m/In1. Further, as the spray nozzle 7, the shape of the spray 10 onto the sheet-like material 10 is a conical shape with a space inside as shown in FIG.
/4 HKB60063BW) is adopted, and the injection angle α is 6.
0°, this is a 20m pitch (L=204Il11)
Rn 40 pieces in a straight line in the width direction of the sheet-like material 1,
The facing distance between the spray nozzle 7 and the sheet material 1 (polyester) is 1! Let lla be 20 INR. Further, as the coating liquid 9, an aqueous low melting point polyester liquid having a viscosity of 2 cps is used, and is supplied to the spray nozzle 7 by a -axis eccentric screw pump (trade name: MONO PUMP). Furthermore, as the air knife 4, a jNNO36IIm with a discharge width of 800 m was used,
The Aero boat was adjusted so that the final coating thickness of R was 10 μm. Under the above conditions, the supply amount of n10 from the spray nozzle 7 to the surface of the sheet-like material 1 is gradually reduced, and
The corresponding coating form 11B was investigated.

The experimental results show that even if the amount of spray 10 supplied from the spray nozzle 7 to the surface of the sheet-like material 1 is 20% more than the essential coating layer, that is, about 1.2 times the essential coating layer m, excellent quality can be achieved. I got something. Note that with conventional equipment, uniform coating with a final coating thickness of 30 μm or less was impossible.

Also, one of the effects of the present invention! For fIH, the coated sheet material 1 was wrapped in adhesive [1-lue (made of polyurethane, hardness 300)], and the number of adhered dust particles of 50 μm or more was counted. In the conventional air knife coater, when the amount of dust supplied from the coating means to the sheet-like object was 10 times or more than the required coating M, the number of dust particles was 150 pieces/Td; Spray on surface 7110
When the supply m was reduced to 20% more than the required coating, it was reduced to 100 pieces/g. That is, as above,
By supplying the coating liquid 9 to the sheet-like object 1 through the spray nozzle 7 and suppressing the flow of excess coating liquid 14 as much as possible, the amount of dust that gets mixed in during the circulation of the coating liquid is reduced, and the coated surface becomes more uniform. The surface became beautiful and its quality improved.

In the above embodiment, the booth 3 was used to collect the spray n10 scattered around the spray nozzle 7 when the coating layer was formed by the coating means 2, but in addition to the booth 3, the booth 3 and the sheet Air may be sent between the shaped objects 1 or the inside of the booth 3 may be suctioned, and in these cases, the recovery efficiency is further improved.

In addition, in the above embodiment, the spray nozzle 7 used is one in which the shape of the spray ta 10 onto the sheet-like material 1 is a conical shape with a space inside as shown in FIG. 4, but the spray nozzle 7 is not limited to this. Rather, the point is that any shape can be used as long as it can supply a small amount of the spray 10 onto the surface of the sheet-like material 1, such as a conical shape with a solid interior as shown in FIG. 5, a fan shape as shown in FIG. 6, etc. good.

Further, as shown in the above embodiment, when the spray nozzles 7 are arranged in a straight line in the width direction of the sheet-like material 1, the spray 1 is sprayed from each spray nozzle 7 onto the surface of the sheet-like material 1.
There is a certain range for the suspension of 0, and there is no injection beyond this range.
10 cannot be changed. The reason is,
Although the suspension of the spray 10 is determined by the pump pressure and is proportional to the square root of that pressure, there is a certain upper limit to the pressure that can be applied to the spray nozzle 7, and the spray nozzle 7 This is because a pressure above a certain level is required in order to make the jet S''A 10.

However, by employing the method described below, it is possible to change the ti of the spray 10 beyond the above range.

First, as described above, the pitch L of the spray nozzle 7 is determined using equation (3). Then, as shown in FIG. 7(a),
Two coating liquid supply vibrators 8a and 8b are prepared, and 0 spray nozzles 7a and 7b are arranged in a staggered manner for each with a pitch of 21. It is off by L.). Here, for convenience of explanation, the range of the supply amount of the one-piece spray nozzles 7a and 7b is Q□~
Assume that there are 2QOs. At this time, as shown in FIG. 7(b), the amount of spray 10 supplied to the sheet-like material 1 when all the spray nozzles 7a and 7b are used is 2nqO to 4n
Q o.

Here, as shown in FIG. 7(C), the supply of the coating liquid 9 to one of the coating liquid supply vibrators 8b is stopped, and the spray nozzle 7a and the sheet-like material 1 are connected so that the formula (2) is satisfied. Adjust the distance a. That is, spray nozzle 7 with pip 2L
a are arranged in a straight line in the width direction of the sheet-like material 1, and the spray 10 is supplied to the sheet-like material 1 at an appropriate distance 11a. At this time, the supply amount is nq to 2 n q□, as in the above embodiment. Therefore, by appropriately switching the supply method and distance a of the coating liquid 9 as described above, the supply range from nq to 4 nqo can be covered, and the supply amount range is doubled. Although the case where two coating liquid supply vibrators 8a and 8b are prepared has been described here, it goes without saying that three or more may be prepared and the range of the supply 11 may be expanded in the same manner as described above.

Further, although a one-fluid nozzle is used in this embodiment, a two-fluid nozzle in which the coating liquid 7 and air are mixed may be used.

(Effects of the Invention) Hereinafter, as shown in F, according to the present invention, a coating layer that is necessary for forming a coating layer with a final coating thickness on the surface of the sheet-shaped article from the spray nozzle toward the surface of the sheet-shaped article. After spraying 1 to 2 times the amount of the coating liquid to form a coating layer, use an air knife to scrape the upper layer of the coating layer to adjust the thickness of the coating layer to the final coating thickness. Therefore, a thin and uniform coating surface can be formed on the sheet material without contact. Moreover, since the supply 1n of the sprayed coating liquid from the spray nozzle to the sheet-like object is 1 to 2 times the amount of coating m required to form the final coating layer on the surface of the sheet-like object. The amount of surplus coating liquid present in the coating layer is zero or very small, and the contamination of dust and the like during the circulation of the coating liquid is greatly reduced, and the quality of the coated surface can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of a coating apparatus according to the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a view taken along the line A-A in FIG. FIG. 4 to FIG. 6 are diagrams showing the shape of the spray supplied to the sheet-like material, and FIG. 7(a) is a diagram showing another embodiment of the coating apparatus according to the present invention. FIG. 7(b) is a partial plan view showing the configuration.
, (c) are diagrams for explaining the operations of the respective embodiments. 1...Sheet-like material, 2...Coating means, 4.
...Air knife, 7...Nozzle, 9...
Coating liquid, 10... Spraying, a... Distance,
shi...pitch, α...injection angle diagram L----1σ・7su)-87----) Sparuki-11kutA1 corner diagram a b b

Claims (2)

[Claims] (1) In a coating method in which a coating liquid is continuously and evenly applied to a final coating thickness on a sheet-like object traveling in a predetermined direction, a plurality of spray nozzles are arranged in the width direction of the sheet-like object facing the surface of the sheet-like object. Spray the coating liquid in a spray form from 1 to 2 times the coating layer required to form a coating layer with the final coating thickness on the surface of the sheet-shaped article, and apply. After forming the layer, an air knife provided facing the surface of the sheet-like material downstream from the position of the spray nozzle with respect to the traveling direction of the sheet-like material is used to scrape the upper layer of the applied layer. A coating method characterized in that the thickness of the coating layer is adjusted to the final coating thickness. (2) In a coating device that continuously and uniformly applies a coating liquid to a final coating thickness on a sheet-like object traveling in a predetermined direction, a spray nozzle that sprays the coating liquid at a spray angle α is provided on the surface of the sheet-like object. A plurality of spray nozzles are arranged facing each other at a pitch L in the width direction thereof, and are arranged such that a distance a between the sheet surface and the spray nozzle satisfies a≧L/2tan (α/2), Spraying the coating liquid in the form of a spray from a spray nozzle toward the surface of the sheet-like object in an amount of 1 to 2 times the amount during the coating period required to form a coating layer with the final coating thickness on the surface of the sheet-like object. a coating means for forming a coating layer; provided facing the surface of the sheet-like article downstream from the position of the coating means with respect to the traveling direction of the sheet-like article;
and an air knife for adjusting the thickness of the coating layer to the final coating thickness by scraping the upper layer of the coating layer.