JPH06178959A - Striped film coating method and its nozzle assembly - Google Patents

Abstract

PURPOSE:To definitely delineate the boundary lines at both side edges of a coated striped film and to uniformize the thickness of the film by blowing air flows from both sides to the thick parts at both side edges of the bamboo leaf shape liquid films discharged from a nozzle, thereby holding the liquid film under a pressure. CONSTITUTION:The air flows A1a, A1b, A2a, A2b are struck from two pairs of air nozzle holes 3a1, 3a2, 4a1, 4a2 opposing each other against the air spots As1, As2 at two spots of the thick parts on both side edges Fe1, Fe2 from diagonal above both sides of the liquid film F1 onto the bamboo leaf shape liquid film F1 discharged form the liquid discharge nozzle 1 for an extremely small- width curtain coater, by which the mentioned above thick parts are clamped under the pressure and are made thinner. In addition, the small liquid drops Ld generated and splashed together with the discharged liquid film F1 by the air downflows A1f, A2f on both sides where the air flows A1a, A1b, A2a, A2b join are confined into the inner side. As a result, the striped film which is distinctly delineated at the boundary line edges on both sides and is uniformized in the thickness is coated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stripe film coating method using a liquid discharge nozzle for a curtain curtain coater having a very small width, and a nozzle assembly thereof.

[0002]

2. Description of the Related Art Heretofore, plastic film coatings have been widely used for paper and the like. However, recently, those that target small items such as electronic boards,
That is, the number of coatings for narrow width has increased rapidly. The conventional T
Instead of a die-type nozzle, a small liquid discharge nozzle for a curtain curtain coater with a very small width is used. Because the nozzle is small, it closely resembles an airless spray nozzle.
The nozzle holes are slit-shaped or eye-shaped with a lateral width of 2 to 3 mm. From the same nozzle, low viscosity (10
cps / 20 ° C) k liquid resin at low pressure (1 kg / c
(around m ² ), it is discharged onto a bamboo leaf-shaped liquid film and its width is relatively narrow (10 to 30 mm), and it is applied to the surface of the object to be coated. However, various problems occurred in the coating. It is Figure 1
As shown in 1- (C) and (D), a large number of droplets (Ld) are applied (Lda) on both sides (Fe ₃ a, Fe ₄ a) of the coated stripe. As a result, the border lines are blurred, and the other side is that the edges of both sides of the coated striped film are irregularly thickened, and thin folds (Ff) are formed inside them.

The former reason is that the small droplets (Ld) are scattered and scattered at the same time when the liquid film ejected from the nozzle hole is ejected (FIGS. 11- (A) and (B)), and the latter. The reason for the thickening is as follows. That is, when the liquid is ejected from the slit-shaped nozzle hole having a narrow width, both end portions (72e) of the nozzle hole have a greater resistance to the flow than the central portion (72c) thereof, so that the ejected liquid film Since the flow velocity (v ₂ ) of both side edge portions (Fe ₃ , Fe ₄ ) of (Fl) is smaller than the flow velocity (v ₁ ) of the central portion, it is thicker than the central portion. Then, the liquid film in the central portion where the flow velocity is large becomes thinner and reaches the surface of the object to be coated one after another, and folds (Ff) occur because the layers are applied and overlapped with each other. The film or striped film has a non-uniform thickness. As described above, there are various problems in coating the striped film.

[0004]

In the stripe coating of a liquid by a liquid discharge nozzle for an extremely small width curtain coater, small droplets are applied to the outer sides of both side edges of the coated striped film so that their boundary lines are formed. It is unclear and the thickness of the coating film is not uniform, and it is an object of the present invention to solve these problems.

[0005]

DISCLOSURE OF THE INVENTION The object of the present invention is, in coating with a liquid discharge nozzle for a very small width curtain coater, to sharpen the boundary lines on both side edges of the coated striped film, and Providing a method of uniform thickness and a nozzle assembly therefor.

The gist of the present invention is that the air flow is opposed to the thick portions on the both side edges of the bamboo leaf liquid film discharged from the liquid discharge nozzle for an extremely small width curtain coater from diagonally above both sides of the liquid film. By spraying on both sides of the thick portion to reduce the thickness, and ejecting small droplets ejected from the nozzle hole to scatter,
A method for coating a striped film, which is surrounded by air descending flows from both sides to shield the film from scattering outward, and a nozzle assembly thereof.

The method of the present invention will be described with reference to the drawings. Please refer to FIGS. 1- (A) and (B) first. 5 cps / 20 from slit type (or eye type) nozzle (1) with narrow width
The low-viscosity liquid at around ℃ is discharged as a bamboo leaf liquid film under a low discharge pressure of around 0.3 kg / cm ² . As described in the section of the prior art, a thick portion is formed on both side edges (Fe ₁ , Fe ₂ ) of the bamboo leaf liquid film (Fl) (see FIG. 2).
Therefore, aiming at each spot (As _1, As ₂ ) on the same portion, air nozzle holes (3a ₁ , 3a ₂ ; 4a ₁ , 4a
₂ ) two air streams (A ₁ a, A ₁ b; A ₂ a,
A ₂ b) is blown out at a pressure of about 1 kg / cm ² , and the two spots (As ₁ , As ₂ ) are hit against each other at an acute angle (α) and sandwiched. The cross section C-C at that time is as shown in FIG. That is, the thick portions (Fe ₁ , Fe ₂ ) on both side edges of the liquid film are thinned by being pinched by the above two air streams (A ₁ a, A ₁ b; A ₂ a, A ₂ b) respectively. Fe ₁ a, Fe ₂ b).

The two pairs of air streams are connected to the spot (As
, As) and join and fall while surrounding both side edges of the liquid film. The air descending flow (A ₁ f, A ₂ f)
Is a thick part (Fe ₁ , Fe on both side edges of the liquid film (Fl)
₂ ) The flow velocity is in contact with both sides, but their velocity distribution is as shown in Fig. 4- (B). That is, both edges are large (v
a ₂ ), and the central part is small (va ₁ ).

This is the velocity distribution diagram (v) of the flow of the liquid film on the diagram of FIG. 11- (A) as explained in the section of the prior art mentioned above.
It is the opposite of ₁ > v ₂ ). That is, the air downflow (A ₁
f, A ₂ f) descends toward both side edges of the liquid film (Fl) flowing down with a velocity (va ₂ > va ₁ ) higher than that in the central portion, so that the same air descending flow ( The contact frictional force between the liquid film (A ₁ f, A ₂ f) and the liquid film (Fl) promotes an increase in the flow-down velocity of the thick wall portions on both sides of the liquid film, and promotes further thinning. Further, on the surface of the liquid film (Fc in FIG. 1- (A)) applied on the surface of the object to be coated (O), the air descending flow further presses the non-uniform portion of the wall thickness. The thickness of the liquid film coated on the entire surface, that is, the stripe film (Fc) is made uniform.

The above-mentioned air descending flow (A ₁ f, A ₂ f)
Since the hem is widened and surrounds both sides of the liquid film, the air flow also captures small droplets scattered at the same time as the liquid film to prevent them from scattering to the surroundings. It prevents the blurring.

As described above, according to the present method, the thickness of the coated stripe is uniform, the small droplets are not scattered outwardly on both sides of the stripe, and clear stripe coating of both side edges can be obtained. . The low viscosity of the above liquid of about 5 cps / 20 ° C. was 1 to 10 c
Within the range of ps / 20 ° C., and about 0.3 kg / cm ² of the discharge pressure of the liquid, 0.1 to 0.5 kg /
It is preferably within the range of cm ² .

[0012] Furthermore, about 1 kg / cm ² of ejection pressure of the air flow described above is preferably in the range of 0.7~1.3kg / cm ^2. Beyond that, the liquid film is damaged, and
This is because if it is less than that, the pressure applied to the thick portion of the air flow decreases.

Further, the air flow (A ₁ a, A ₁ a, from both sides at the center point (As ₁ p) of the spot where the air flows intersect.
The angle at which A ₁ b; A ₂ a, A ₂ b) intersect with each other is preferably within the range of 50 degrees to 70 degrees of the acute angle (α), and the position thereof is closer to the center than the nozzle hole (2). It is desirable to set the distance (H) within the range of 7 to 15 mm on the line. This is because, if the distance or height, when lower, for example, as shown in FIG. 5, when the height 5mm position (H _1), the mechanical structure of the nozzle assembly, from opposite sides The angle at the intersecting point (As ₁ pa) of the air flow (A ₃ a, A ₃ b) is an obtuse angle (α ₁ ). Then, the collision force of both airs becomes larger, the liquid film is more likely to be damaged again, and the confluence of both airs does not drop smoothly, and the thinning effect on the thick portion is also reduced.

When the distance is further increased, the space from the nozzle hole (2) to the center point of the spots (As ₁ , As ₂ ) becomes large as shown in FIG. Since it is (H ₂ ), the barrier against small droplets scattered from the nozzle hole becomes small, and as in the conventional case, they adhere to the periphery of the coated stripe and blur the boundary line of both side edges thereof. It will be. Further, since the distance is long, the viscosity of the thick portions on both side edges of the liquid film becomes large due to the air cooling during that time, the pressurizing effect by the air becomes small, and it becomes difficult to make the liquid film uniform.

Next, the structure of the nozzle assembly of the present invention based on the above method will be described. See Figures 7- (A) and (B) and Figure 8. Both side surfaces of the nozzle mounting neck shaft (13) on the gun (11) are parallel to each other, and air nozzle mountings having the same structure centered on the axis (CL) of the liquid discharge nozzle (1) are mounted on the surfaces. Body (10,1
0A) is attached via an air nozzle attachment body (15, 15A). The insides of these air nozzle mounting bodies are made flat surfaces (20, 20A) facing each other at a required angle (β), and laterally long grooves (19) are respectively provided on the surfaces, and the grooves are the air nozzle mounting bodies. (15, 15A) Air passage (1
8 and 17) and communicates with the air supply port (16).

Next, both flat surfaces (20, 20A)
The inclined plate (21, 21A), the sealing sheet (22, 22A), and the nozzle plate (21.
21A) are piled up and tightened by bolts (25) or the like. In addition, on these inclined plates (21, 21A),
A horizontally elongated hole (24) is formed along the horizontally elongated groove (19) on the flat surface (20, 20A) of the air nozzle mounting body (15, 15A). The nozzle plate (2
, 23A), a plurality of air nozzle holes (28a, 28b, 28c ...; 29) along the laterally long hole (24).
a, 29b, 29c ... / 28Aa, 28Ab, 28Ac
...; 29Aa, 29Ab, 29Ac ...) are provided, and these are symmetrically arranged in plural pairs about the longitudinal center plane (CF) of the plate. A sealing sheet (22, 22A) is sandwiched between the nozzle plate (23, 23A) and the inclined plate (21, 21A), and the sealing sheet (22, 22A) is placed on the sheet. The nozzle plate (23,
23A) a plurality of air nozzle holes (28a, 28b,
28c ...; 29a, 29b, 29c ... / 28Aa, 28
Ab, 28Ac ...; 29Aa, 29Ab, 29Ac ...)
Only one symmetrical pair of holes (26, 27) corresponding to the air nozzle holes is to be drilled.

The air nozzle holes (28a ...; 29)
a ... / 28Aa ...; 29Aa ...) is in principle perpendicular to the surface of the nozzle plate (23, 23A), but as in the inclined plate (21, 21A), the air flow In order to change the spray angle (α) of the nozzles without changing the angle of the inclined plate as described above, the angle (α) can be changed even if the nozzle holes are tilted and drilled. The same result is obtained.

Further, the sealing sheets (22, 22)
The pair of holes on A) needs to be prepared for each pair.

[0019]

The operation of the nozzle assembly of the above invention will be described. See Figures 7- (A) and (B) and Figure 8. Since this operation is almost the same as that described in detail in the method section of the means for solving the above-mentioned problems, only the point will be described. The thick portions on both side edges of the bamboo leaf liquid film (Fl) discharged from the liquid discharge nozzle (1) are
Air streams (A ₁ a, A ₁ b; A ₂ a, A) blown from the air nozzle holes (eg 28 b, 29 b) on both sides toward the air spots (As ₁ , As ₂ ) obliquely downward.
The clamping pressure of ₂ b) is thinned, and the liquid film (Fl)
At the same time, the small droplets that scatter are the air descending flow (A ₁
f, A ₂ f) and enclose them, and the thickness is made uniform on the coated object (O) surface by both of the above actions.
Moreover, a clear liquid film (Fc), that is, a stripe coating, on the boundary lines on both side edges can be obtained.

Further, the setting of the approach angle (α / 2) to the center point of the spots (As ₁ , As ₂ ) can be obtained by selecting various kinds of the inclined plates (21, 21A) having different inclination angles. At the same time, the height of the spot position can be adjusted. Further, the span of each pair of positions of the spots (As ₁ , As ₂ ) is set by the above-mentioned sealing sheet (2
2, 22A) with holes (eg 2
6 and 27) can be prepared in advance and can be set stepwise by selecting them.

Further, as a general rule, the axial center direction of the air nozzle hole is formed at a right angle on the surface of the nozzle plate (23, 23A). You can change the direction.

[0022]

【Example】

(First Embodiment) In the air flow for spraying described in the method section of the means for solving the problems, when the working atmosphere is particularly cold or when the viscosity of the liquid to be handled is particularly high. In order to make it have an appropriate small viscosity, etc., it is performed by heating the air stream to an appropriate temperature,
The thickness of the thick portion is reduced more effectively.

(Second Embodiment) The structure described in the section of the structure of the nozzle assembly in the section of means for solving the problem is that the air nozzle mounting body (30, 30A) is the nozzle assembly on the gun (11). The sliding block (44) is mounted and fixed on the three-dimensional neck shaft (43) in this embodiment, as shown in FIGS. 9- (A) and (B). The block (44) is slidably fitted on the cervical shaft (43) and vertically moved. Thereby, the air nozzle holes (28a, 28b, ...
, 29a, 29b, ...) vertically moved to move both spots (As ₁ , As ₁ , from the tip of the liquid discharge nozzle (1)).
Position of As ₂ ), that is, the intersection of both air flows (As ₁ p, As ₂
The height (H ₄ , H ₅ ) up to p) is adjusted steplessly.

(Third Embodiment) In the second embodiment, the position of the air nozzle hole is adjusted up and down by vertically moving the sliding block (44). -As shown in (A),
On the air nozzle mounting body (35, 35A), an inclined plate integrally combined with the nozzle plate,
The attached air nozzle mounting body (3
5, 35A) and is moved diagonally up and down along the flat surface (40, 40A) (in the s or t direction) to locate the nozzle hole, that is, the position of the intersection of the air flows from both sides (Asp ₁ or Asp _1). It changes a). Therefore, the bolt holes formed on the inclined plate, the nozzle plate, and the sealing sheet are oval (31, 32,
33).

(Fourth Embodiment) In the above two embodiments, the adjustment of the vertical direction of the nozzle holes was stepless, but the span of these nozzle holes was stepwise. In this embodiment, of course, the span and angle of each pair of nozzle holes are all stepless. First, the structure will be described. See Figures 10- (A) and (B). Neck shaft (53) for mounting the nozzle on the liquid discharge gun
The slide block (54), which slides on the upper side, is mounted in the same manner as in the second embodiment, but two pairs of directional mounts (55a, 55b) are mounted on both sides of the slide block (54). 56a, 56b) are symmetrically attached to each pair about the axis of the nozzle neck shaft (53), and tubular air nozzles (59a, 59b; 60a, 60b) are attached to the directional attachments, respectively. Are attached facing each other.

Next, the operation of the above nozzle assembly will be described.
The directions of the air nozzles are set in all directions. Therefore, the angle (α) where these air nozzles merge and the spot (As) of the air flow from the tip of the liquid ejection nozzle
The height (H6 or H7) up to the center point (As ₁ p or As ₁ pa) of ₁ , As ₂ ) can be set easily in a stepless manner. Also, the span of the two confluence points (for example, W ₁ or W ₂ shown in FIG. 10- (B)) can be changed steplessly by changing the directions of the nozzles, and further, the height (H5 ) Can be set steplessly by adjusting the sliding block (54) vertically.

[0027]

According to the method of the present invention and the use of the nozzle assembly based on the method, in the film coating by the liquid discharge nozzle for the ultra-small width curtain coater, the border lines on both sides of the coated striped film are sharp. In addition, the thickness of the film is uniform and a high quality striped film coating can be obtained.

[Brief description of drawings]

FIG. 1A is an explanatory view of a central cross section of a film forming state from a nozzle in the method of the present invention, and FIG.

FIG. 2 is a cross-sectional view taken along the line BB of FIG. 1- (A).

FIG. 3 is a cross-sectional view taken along line CC of FIG. 1- (A).

FIG. 4A is a cross-sectional view taken along the line DD of FIG. 1-A, and FIG. 4B is a velocity distribution diagram of the liquid film on the cross section on the left.

FIG. 5 is a diagram for explaining height of a position of a spot center point.

FIG. 6 is an explanatory view of the action on the liquid film when the spot position is low.

7A is a side sectional view of a nozzle assembly diagram of the present invention, and FIG. 7B is a sectional view taken along line EE thereof.

FIG. 8 is an explanatory view of a mounting sequence of the nozzle plate, the sealing sheet, the inclined plate and the like in the above invention.

FIG. 9A is a vertical cross-sectional view of the second embodiment,
(B) is the FF side sectional view.

10A is a side view of a nozzle assembly according to a fourth embodiment of the present invention, and FIG. 10B is a front view thereof.

FIG. 11A is an explanatory view of a film formation state of a bamboo leaf liquid film of a conventional low viscosity liquid at a low discharge pressure. (B) is a cross-sectional view taken along line GG in the above figure, (C) is a cross-sectional view of application of the liquid film,
(D) is a plan view of the above figure (C).

[Explanation of symbols]

2 liquid discharging nozzle holes _{3a 1, 3a 2, 4a 1} , 4a 2 air nozzle holes 10,10A air nozzle mount 13,43,53 peg nozzle mounted on gun 14, 54 sliding Day ring blocks 15, 15A, 35, 35a Air nozzle mounting body 19 Horizontal groove 20, 20A Flat surface 21, 21A Inclined plate 22, 22A Sealing sheet 23, 23 Nozzle plate 24 Horizontal hole 26, 27 A pair of selected holes 28a, 28b, 28c ...; 29a, 29b. , 29c ...
Each nozzle hole of each pair 30, 30A Air nozzle mounting body 50, 50A Universal air nozzle mounting body 55a, 55b, 56a, 56b Universal direction setting tool 59a, 59b, 60a, 60b Tubular air nozzle A ₁ a, A ₁ b, A ₂ a, A ₂ b Air flow A ₁ f, A ₂ f Air falling flow As ₁ , As ₂ spot As ₁ p, As ₂ p Center point of the above spot Fl Liquid film Fe ₁ , Fe ₂ Both side edges of liquid film H, H ₁ , H ₂ , H ₃ , H ₄ , H ₅ , H ₆ , H ₇ Distance from the tip of the liquid discharge nozzle hole to the center point where the air flow center line intersects

Claims (10)

[Claims] 1. A thick portion on both side edges (Fe ₁ , Fe ₂ ) of a bamboo leaf-shaped liquid film (F1) discharged from a liquid discharge nozzle (1) for a curtain curtain coater having an extremely small width. To the two spots (As ₁ , As ₂ ) of the liquid film through two pairs of air nozzle holes (3a ₁ , 3a ₂ ; 4a ₁ , 4a ₂ ) facing diagonally from both sides of the liquid film. A stream (A ₁ a, A ₁ b; A ₂ a, A ₂ b) is applied, and the thick portions are pressed to make them thinner (Fe ₁ a, F
e ₂ b) and the air descending flow (A ₁ f, A ₂ f) on both sides where the air flow merges, the small droplets (Ld) generated and scattered with the liquid film to be ejected are confined inside, and A striped film coating method for coating a striped film having a sharp edge and a uniform thickness. 2. The viscosity of the discharged liquid is 1 to 10 cs.
The striped film coating method according to claim 1, which is in the range of p / 20 ° C. 3. The discharge pressure of the liquid is 0.1 to 0.5 k.
The method of coating a striped film according to claim 1, which is in the range of g / cm ² . 4. The jet pressure of the air flow is 0.7 to 1.3.
The striped film coating method according to claim 1, which is in the range of kg / cm ² . 5. The position where the air flow strikes is 8 to 12 mm on the center line from the tip of the liquid discharge nozzle.
The method of coating a striped film according to claim 1, wherein 6. The striped film coating method according to claim 1, wherein the air is heated. 7. A pair of air nozzle mounts (10, 10A) having the same structure are symmetrically arranged on parallel surfaces on both outer sides of a neck shaft (13) for mounting a nozzle assembly on a liquid discharge gun (11). Attached to the body (15, 15) of the air nozzle mounting body.
A surface facing diagonally downward to the inside of A) is a flat surface (2
0, 20A), and each of the flat surfaces is provided with a laterally long groove (19), and the groove is formed in the air nozzle mounting body (1).
0,10A) air nozzle mounting body (15,15A)
A) the air passages (18, 17) provided inside and the air supply ports (16) thereof are communicated with each other, and the inclined plates (21, 21A) are provided on the respective flat surfaces (20, 20A).
A), the sealing sheet (22, 22A), the nozzle plate (23, 23A), etc. are piled up and joined together by a bolt (25), and the inclined plate (21, 21A) is aligned with the laterally long groove (19). A horizontal oblong hole (24)
Further, on the nozzle plate (23, 23A), nozzle holes (28a, 29a; 28b, 29b; 28c, 29) symmetrically distributed to both sides around the center plane (CF) are provided.
c)) is opened, and on the sealing sheets (22, 22A) sandwiched between them, in the plurality of pairs of air nozzle holes on the nozzle plate (23, 23A),
Only the required pair of air nozzle holes and corresponding holes (2
6, 27) are opened, and the holes are further provided with the inclined plate (21,
21A) a nozzle assembly for striped film coating, characterized in that the nozzle assembly is in communication with the oblong hole (24) above. 8. A nozzle assembly mounting neck shaft (43) on the liquid discharge gun is cylindrical, and a sliding block (44) is slidably fitted on the shaft (13) to form the block (4).
The striped film coating nozzle assembly according to claim 7, wherein air nozzle mounting bodies (30, 30A) having the same structure are mounted on the parallel surfaces outside the surface of (4). 9. The pair of inclined plates (21, 21A), the sealing sheets (22, 22A), and the nosle plates (23, 23A) have elliptical bolt holes (31, 32, 32).
33) The nozzle assembly for striped film coating according to claim 7. 10. A liquid ejecting nozzle mounting neck shaft (53)
A sliding block (54) is mounted on the upper side, and two pairs of free-direction setting tools (55a, 55b; 56a56b) are symmetrically arranged on both outer sides of the block, respectively, with respect to the central axis (CL) of the nozzle. Attached to the free direction setting tools (55a, 55b, 56)
The striped film coating nozzle assembly is characterized in that tube-shaped air nozzles (59a, 59b; 60a, 60b) are attached on a and 56b, respectively.