JP4857217B2 - Coating method and coating apparatus - Google Patents

Description

This invention relates to a coating method and coating equipment supplying coating as coating liquid for example an adhesive to a substrate, particularly to uniformly applying a technique containing insoluble particulate adhesive to a substrate .

  As a coating means, a direct method or a reverse method using a roll for coating a coating liquid on a long base material such as paper or a plastic film is known. Further, insoluble pigments and dyes are dispersed to color the coating liquid, or insoluble inorganic or organic particles are dispersed as fillers.

  However, when these coating liquids are applied to the substrate by the above-described method, the coating liquid stays and flows in the liquid reservoir portion with the rotation of the roll, so that the dispersion becomes hard. As a result, there was a problem that the dispersion was applied to the substrate in a non-uniform state, causing defects due to uneven color due to non-uniform pigments and uneven physical properties due to non-uniform fillers.

In order to solve these problems, as shown in FIG. 9, a roll-shaped rotating body 32 is provided in the liquid reservoir 3 so as to face the comma roll 30 and the coater roll 31, and a drive source 33 such as a motor is interposed. The adhesive s is forcibly circulated by rotating and the adhesive s is agitated to make the distribution of the dispersion uniform (see Patent Document 1).
JP 2000-225370 A

However, the conventional means described above has the following problems.
When powder having an insoluble and different specific gravity is dispersed in the coating liquid by the above means, the dispersion having a different specific gravity is separated or precipitated by the circulating flow actively generated in the liquid reservoir, resulting in the pigment being dispersed. There is a problem in that unevenness in color and dispersion of fillers are non-uniform, and quality defects cannot be eliminated.

The present invention has been made in view of such circumstances, and a coating method and a coating method that can be applied to a substrate while maintaining a uniform distribution of a dispersion contained in a pressure-sensitive adhesive as a coating liquid. a main object to provide a KoSo location.

The present invention has the following configuration in order to achieve the above object.
In the first invention, the pressure-sensitive adhesive stored in the liquid reservoir is fed from a gap formed between upper and lower opposed rolls and applied to a substrate that is wound around at least one of the rolls and travels. In the roll coating method of coating,
The adhesive is applied to the base material while supplying the adhesive between the two rolls through a stirring member provided with a plurality of holes provided in the liquid reservoir so as to face the roll. And

  (Operation / Effect) According to the above method, the circulation of the pressure-sensitive adhesive is generated in the liquid reservoir by the rotation of the pair of rolls. When the pressure-sensitive adhesive is drawn between the rolls on the circulating flow, it passes through the holes of the stirring member disposed opposite to the rolls. At this time, the flow rate of the pressure-sensitive adhesive passing through the hole is increased, and a stirring action is generated between the stirring member and the roll. That is, the content of the dispersion contained per unit flow rate is made uniform by the stirring action. Moreover, it can suppress that a dispersion precipitates in the bottom part of a liquid reservoir part with a stirring member.

  Therefore, since a pressure-sensitive adhesive in which a dispersion of pigments, dyes or fillers is uniformly distributed can be applied to the substrate, a high-quality pressure-sensitive adhesive tape with no color unevenness or stable physical properties can be produced.

The second invention is a coating apparatus for coating the base material with the adhesive stored in the liquid reservoir.
A pair of upper and lower rolls arranged opposite to each other while being laid around the liquid reservoir and winding a base material on one side,
A stirring member having a plurality of holes formed in the front liquid reservoir and facing at least the lower roll of the rolls;
It is provided with.

  (Operation / Effect) According to this configuration, the pressure-sensitive adhesive passing through the stirring member provided in the liquid reservoir is stirred. Moreover, precipitation of the dispersion contained in the pressure-sensitive adhesive is suppressed by the stirring member. That is, the first method invention can be suitably realized.

According to a third invention, in the second invention,
An adhesive supply pipe arranged with the outlet positioned below the liquid level of the liquid reservoir, and
An adhesive supply means for pumping the adhesive to the adhesive supply pipe;
Control means for controlling the operation of the adhesive supply means so that the liquid level of the adhesive stored in the liquid reservoir is higher than the stirring member;
It is provided with.

  (Operation / Effect) According to this configuration, the liquid level of the adhesive in the liquid reservoir supplied from the adhesive supply means is configured to be maintained higher than that of the agitating member. The agent will not adhere and dry. Therefore, the solid material of the pressure-sensitive adhesive does not mix with the liquid and cause a quality defect.

4th invention is 2nd or 3rd invention,
The diameter of the hole formed in the stirring member is 3 to 15 mm, and the opening ratio is 30 to 80%.

  (Operation / Effect) According to this configuration, the adhesive is efficiently passed through the hole without hindering the circulation of the adhesive. That is, the stirring efficiency of the adhesive is not reduced. As a result, the dispersion contained in the pressure-sensitive adhesive can be uniformly distributed.

  According to the coating method and the coating apparatus according to the present invention, by disposing the stirring member having a plurality of holes formed in the liquid reservoir so as to face the roller, the adhesive that passes through the stirring member is provided. The flow rate is increased, and the adhesive is stirred between the stirring member and the roll. Therefore, a high-quality pressure-sensitive adhesive tape capable of coating a base material with a pressure-sensitive adhesive having a uniform distribution can be produced. Moreover, it can also suppress that the dispersion contained in an adhesive precipitates in the bottom part of a liquid storage part by a stirring member.

  An embodiment of the present invention will be described below with reference to the drawings.

  1 and 2 show a schematic configuration of a coating apparatus according to the present invention. This coating apparatus is a roll coat system, and is composed of a coating roll 1, a back roll 2, and a liquid reservoir 3 that are arranged opposite to each other at a predetermined interval.

  The coating roll 1 controls the transfer amount of the adhesive s. For example, the back roll 2 is wound around a flexible support 4 having a belt shape, and the transfer amount of the adhesive s is controlled by a gap formed by the coating roll 1.

  The liquid reservoir 3 is composed of a liquid reservoir plate 5 for storing the adhesive s and a pair of side plates 6 for adjusting the coating width.

  In the liquid reservoir, a stirring plate 7 is provided in close proximity so as to face the back roll 2. As shown in FIGS. 2 to 4, the stirring plate 7 has a plurality of holes 8 formed on the surface thereof and is refracted along the curvature of the back roll 2.

  The hole 8 of the apparatus of this embodiment is circular, and its diameter is set in the range of 3 to 15 mm, preferably in the range of 5 to 12 mm, depending on the adhesive s used. Further, the opening ratio of the stirring plate 7 is set to 30 to 80%, more preferably 40 to 70% by the holes 8 having the size and shape. With this configuration, the pressure-sensitive adhesive s stored in the liquid reservoir 3 is smoothly passed through the hole 8 without preventing the pressure-sensitive adhesive s from circulating with the rotation of the two rolls 1 and 2. Increase flow rate.

  Therefore, even if the adhesive s contains a dispersion such as a pigment, dye, or filler, the adhesive s drawn between the rolls 1 and 2 along the roll surface as the back roll 2 rotates is The back roll 2 and the stirring plate 7 are stirred by the drawing flow and the flow having a high flow velocity passing through the stirring plate 7. That is, the pressure-sensitive adhesive s is applied to the support 4 in a state where the dispersion is uniformly distributed in the pressure-sensitive adhesive s by the stirring action.

  Further, as shown in FIG. 4, the refraction angle θ of the stirring plate 7 is preferably set to 150 to 170 °, and the distance from the coating roll 1 and the back roll 2 is set to a range of 5 to 50 mm. It is preferable. When this distance exceeds 50 mm, a circulating vortex is generated between the rolls 1 and 2 and the stirring plate 7. Due to this circulation vortex, the dispersion is centrifuged and unevenly distributed. On the other hand, when the distance is less than 5 mm, the shearing force acting between the rolls 1 and 2 and the stirring plate 7 increases, and the temperature of the adhesive s rises and changes the physical properties.

  In addition, as a material of the stirring plate 7, the material which does not change with the adhesive s is preferable, for example, stainless steel is used. The thickness is set to a thickness that does not hinder the circulation of the adhesive s and does not reduce the stirring action. In this embodiment, the thickness is set to 1 to 3 mm.

  In this embodiment, as shown in FIG. 5, a pair of upper and lower laminate rolls 10 and 11 are arranged at a predetermined interval, and strip separators 12 a and 12 b are wound around the respective laminate rolls 10 and 11. The configuration is the same as in Example 1 except that the transfer is performed while supplying the adhesive s to both gaps.

  Next, a comparison result of an experiment for manufacturing an adhesive tape or a double-sided adhesive tape using the apparatuses of Examples 1 and 2 and a conventional apparatus in which the stirring plate 7 is omitted from both apparatuses will be shown.

  First, the manufacturing conditions of the adhesive tape by the apparatus of Example 1 are as follows. That is, an adhesive coating solution colored by mixing 3 parts of coronate L and 0.01 part of carbon black into an acrylic adhesive polymerized at 30% base in toluene with BA / BB = 95 parts / 5 parts. Using. In the apparatus of Example 1, WET having a thickness of 100 μm is applied on a PET substrate having a thickness of 38 μm that has been subjected to a peeling process on the back surface.

  After the coating, a drying process was performed at 120 ° C. for 2 minutes in a hot air oven, and the black pressure-sensitive adhesive tape was manufactured by winding and collecting.

  On the other hand, the black adhesive tape was manufactured by the comparative example apparatus which is not equipped with the stirring board 7 on the same conditions as the apparatus of the said Example 1. FIG.

  As a result of the both production experiments, the surface of the pressure-sensitive adhesive tape produced by the apparatus of Example 1 was uniform black. That is, it was confirmed that carbon black was uniformly dispersed in the pressure-sensitive adhesive. On the other hand, as shown in FIG. 6, the adhesive tape T manufactured by the comparative apparatus had a light gray spot pattern on the surface. That is, it was confirmed that the carbon black is unevenly distributed and nonuniform.

  Next, the manufacturing conditions of the double-sided pressure-sensitive adhesive tape by the apparatus of Example 2 are as follows. In other words, 90 parts by weight of 2EHA, 10 parts by weight of AA, and 2,2-dimethoxy-1,2-diphenylethane-1-one as a photoinitiator were added to a 0.1 part by weight stirring tank. The tank is irradiated with ultraviolet rays using an optical fiber type ultraviolet ray device to increase the viscosity to about 30 Pa · s. Thereafter, 0.3 parts by weight of 2,2-dimethoxy-1,2-diphenylethane-1-one as a photopolymerization initiator and 0 hexanediol diacrylate as a cross-linking agent are added to 100 parts by weight of the liquid. Mix 2 parts by weight and stir. Furthermore, 10 parts by weight of glass balloon (Tokai Kogyo Co., Ltd.) was mixed, and then a pressure-sensitive adhesive coating solution colored by mixing 0.01 part of carbon black was used.

This pressure-sensitive adhesive is supplied to the apparatus of Example 2 shown in FIG. 5, and as the upper and lower supports, a non-adhesive treated transparent PET separator having a thickness of 50 μm is used. The gap between the laminate rolls 10 and 11 was adjusted so as to be 1 mm. Also, the feeding speed of the separator is about 5 m / min, and the UV irradiation device uses a high-pressure mercury lamp to irradiate the adhesive tape with UV light at a maximum illuminance of about 300 mW / cm ² and an integrated light quantity of 4000 mJ / cm ² . Curing treatment was performed. Then, the black double-sided adhesive tape was manufactured by winding and collecting.

  On the other hand, a black double-sided pressure-sensitive adhesive tape was produced under the same conditions as in the apparatus of Example 2 above using a comparative apparatus without the stirring plate 7 (Comparative Example 1).

  Moreover, the black double-sided adhesive tape was manufactured using the flat stirring plate 7 in which the hole 8 was not formed on the same conditions as the apparatus of the said Example 2 (comparative example 2).

  As a result of the above production experiments, the double-sided pressure-sensitive adhesive tape produced by the apparatus of Example 2 was uniform black on both the front and back surfaces. That is, it was confirmed that carbon black was uniformly dispersed in the pressure-sensitive adhesive. On the other hand, the double-sided pressure-sensitive adhesive tape produced by the apparatuses of Comparative Examples 1 and 2 had light gray spots on the front and back surfaces, as shown in FIG. That is, it was confirmed that carbon black was unevenly distributed and became non-uniform. Furthermore, in the apparatus of Comparative Example 3, it was confirmed that carbon black was precipitated at the bottom of the liquid reservoir 3. That is, it was confirmed that carbon black having a high specific gravity was not evenly stirred in the liquid reservoir and was unevenly distributed.

  As described above, according to this embodiment apparatus, the stirring plate 7 in which the plurality of holes 8 are formed is disposed close to the coating roll 1, the back roll 2, or the laminate roll 11, The flow rate of the pressure-sensitive adhesive s passing through the holes 8 can be increased to stir the pressure-sensitive adhesive s between the roll 2 or 11 and the stirring plate 7, and the contained dispersion can be uniformly distributed.

  Further, it is possible to avoid the dispersion from being precipitated at the bottom of the liquid reservoir 3 by the stirring action of the stirring plate 7.

  The present invention is not limited to the embodiment described above, and can be modified as follows.

  (1) In each of the above embodiments, the stirring plate 7 is opposed to the back roll 2 or the lower laminating roll 11 and has a refractive shape, but both the stirring plates 7 are connected to the upper coating roll 1 or the laminating roll 10. You may deploy across. Further, as shown in FIG. 7, the shape of the stirring plate 7 may be a curved shape so as to face each other according to the curvature of the rolls such as the back roll 2 and the coating roll 11 instead of the refractive shape.

  By making the stirring plate 7 into the curved shape, the distance between the surface of the back roll 1 or the coating roll 11 and the opposing surface of the stirring plate 7 can be kept the same, so that disturbance of the circulation flow in the gap is avoided. can do.

  (2) As shown in FIG. 8, the liquid reservoir 3 is provided with an upper plate 15 and a brace 16 that is cantilevered so as to be erected on the laminate roll 10 from the tip portion of the upper plate 15. To do. That is, the liquid reservoir 3 is closed. Further, the liquid reservoir 3 is filled with the adhesive s so as to come into contact with the upper plate 15 and the blade 16. In other words, the state where the stirring plate 7 is always immersed in the adhesive s is maintained.

  The blade 16 is flexible, and its tip is preferably tapered so that it is substantially sharp, and a resinous material is used. Further, the blade 16 can be adjusted for sliding movement in the front-rear direction with respect to the laminate roll 10 by loosening a screw 17 attached and fixed to the upper plate 15.

  The tip of the blade 16 is brought into contact with the laminating roll 10 so that the liquid reservoir 3 is substantially sealed, and the stir plate 7 is immersed in the adhesive s so that the laminating rolls 10 and 11 are rotated. Along with this, it is possible to suppress the generation of large bubbles with a diameter of several hundred to several thousand μm, which are generated by the entrainment of air from the liquid surface side. As a result, even when the adhesive s laminated with the separators 12a and 12b is irradiated with ultraviolet rays and cured by photopolymerization to produce an adhesive tape, through holes are generated in the adhesive layer due to the inclusion of bubbles. Can be suppressed, and there is no appearance defect, and a high-quality pressure-sensitive adhesive tape can be produced.

  Moreover, it can prevent that the adhesive s adhering to the stirring board 7 dries and mixes in the adhesive s as a foreign material.

  The attachment of the blade 16 may be configured as follows. That is, pressure sensors are provided at predetermined intervals in the width direction of the blade 16, and the blade 16 is slid by a driving device such as a cylinder based on the result detected by the pressure sensor, and the width direction of the laminate roll 10 is determined. The blade 16 may be adjusted so that the tip of the blade 16 always contacts with a uniform pressure.

  (3) In each of the above-described embodiments and modification examples, the adhesive s is continuously supplied to the liquid reservoir 3 so that the liquid level of the liquid reservoir 3 continues to be higher than the height of the stirring plate 7. It is preferable to configure. As an example of this configuration, the apparatus of the first embodiment will be described as follows.

  The pressure-sensitive adhesive s stored in the pressure-sensitive adhesive tank 18 is pumped to the liquid reservoir 3 by the replenishment pump 19. As the replenishment pump 19, a motor drive type or an electromagnetic drive type connected to the control device 20 is used, and the discharge amount can be arbitrarily adjusted and controlled. Further, an operation unit 21 is connected to the control device 20, and a coating amount is calculated by inputting operating conditions such as a feed speed, a support width, and a coating thickness of the separators 12a and 12b, and its consumption. It is configured such that the same amount of adhesive is supplied. With these settings, the pressure-sensitive adhesive s can be stably supplied so that the liquid level in the liquid reservoir 3 is maintained at a position higher than the height of the stirring plate 7.

  According to this structure, the adhesive s adhering to the stirring plate 7 is not dried. That is, it can be avoided that the dried foreign matter of the adhesive s is mixed in the coating liquid and causes poor coating.

  (4) In each of the above embodiments, instead of the stirring plate 7, a metal wire may be formed in a lattice shape. In this case, the aperture ratio is adjusted by overlapping a plurality of metal grids.

It is a side view which shows schematic structure of the coating apparatus which concerns on Example 1 of this invention. It is a perspective view which shows schematic structure of the roll coater of the coating apparatus which concerns on Example 1 of this invention. It is a top view of a stirring plate. It is a side view of a stirring plate. It is a side view which shows schematic structure of the coating apparatus which concerns on Example 2 of this invention. It is the figure which showed the surface state of the adhesive tape manufactured with the comparative example apparatus. It is a perspective view of the stirring plate of a modification apparatus. It is a side view which shows schematic structure of a modification apparatus. It is a side view which shows schematic structure of a conventional apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coating roll 2 ... Back roll 3 ... Liquid reservoir part 4 ... Support body 7 ... Stirring board s ... Adhesive

Claims (4)

A roll coating method in which the adhesive stored in the liquid reservoir is fed from the gap formed between the rolls facing each other up and down and applied to the substrate that is wound around at least one of the rolls and travels. In the coating method of
The adhesive is applied to the base material while supplying the adhesive between the two rolls through a stirring member provided with a plurality of holes provided in the liquid reservoir so as to face the roll. Coating method. In the coating device that coats the base material with the adhesive stored in the liquid reservoir,
A pair of upper and lower rolls arranged opposite to each other while being laid around the liquid reservoir and winding a base material on one side,
A stirring member having a plurality of holes formed in the front liquid reservoir and facing at least the lower roll of the rolls;
A coating apparatus comprising: In the coating device according to claim 2,
An adhesive supply pipe arranged with the outlet positioned below the liquid level of the liquid reservoir, and
An adhesive supply means for pumping the adhesive to the adhesive supply pipe;
Control means for controlling the operation of the adhesive supply means so that the liquid level of the adhesive stored in the liquid reservoir is higher than the stirring member;
A coating apparatus comprising: In the coating device according to claim 2 or claim 3,
The diameter of the hole formed in the said stirring member is 3-15 mm, and the opening rate is 30-80%. The coating apparatus characterized by the above-mentioned.

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