JPS60225669A - Coating method - Google Patents

Abstract

PURPOSE:To regulate a partial coating amount, by providing the blade contacted with a part of the surface of a rotary bar to a position separate from a web. CONSTITUTION:A coating solution 3 is supplied into the supplied solution guide groove formed between a bar support member 4 and a weir member 6 from the solution supply port 5 supplied to said support member 4 and a blade 11 contacted with a part of the surface of a rotary bar 1 is provided and the supply of the solution to a support can be partially stopped only at the part of the blade 11. Then, only a desired coating amount is applied to a web 2 and the remainder is flowed down to form a liquid sump along with the newly supplied coating solution 3. The coating solution 3 is applied to the web 1 through the blade 11. By this method, the surface property of a film 9 is enhanced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to photographic materials such as photographic film and photographic paper, photolithographic materials, magnetic recording materials such as magnetic recording tape, pressure-sensitive recording paper, and heat-sensitive recording paper. The present invention relates to an improvement in the process of applying a liquid coating composition to a continuously running long flexible support (hereinafter referred to as a "web") in the production of recording materials, and more specifically relates to an improved par coating method. be.

[Prior art]

Conventionally, various methods have been proposed for applying a coating liquid to a continuously running web. Generally, the coating process involves the part where the coating liquid is transferred to the web (hereinafter referred to as "
"Application system". ) and a part that measures the coating liquid transferred to the web to the desired coating amount (hereinafter referred to as the "measuring system"), so coating methods are classified according to the differences between the application system and the measuring system. Ta.

Based on differences in application systems, roller coating methods, dip coating methods, fountain coating methods, etc., and based on differences in metering systems, air knife coating methods, blade coating methods, par coating methods, etc. have been known. In addition, extrusion coating methods, beat coating methods, and curtain coating methods are known as methods in which application and measurement are performed in the same part.

Among these coating methods, the par coating method transfers excess coating liquid to the web, and then scrapes off the excess coating liquid with a parr that is stationary or rotating at a slower circumferential speed in the opposite direction to the web. It is widely used because it allows the desired amount of coating to be applied, and it is capable of coating a thin layer at high speed with simple equipment and operation. Although any method can be used as an application system in the per coating method, the roller coating method, especially the kiss coating method, has been most commonly used to take advantage of its simplicity.

However, in the traditional bar coating method.

Because the application system and measurement system were completely independent, it was not only complicated to set conditions for each separately when dispensing.

It has the disadvantage that it requires a large amount of space and is uneconomical in terms of space utilization.

Japanese Unexamined Patent Publication No. 13-223μ3 proposes a method in which the coating liquid is applied by the parr by supplying the coating liquid so that a liquid pool is formed just before the contact area between the parr and the web, and the operation is easy. It is used as an improved coating method that is easy to use, does not require a large amount of space, and can form a coating film with excellent surface properties.

In the above-mentioned coating process, due to the action of the surface tension of the liquid coating composition, a thick coated film part is generated at both edges in the width direction of the web, and the thick film part is dried in the subsequent drying process. It is desirable to remove this before the drying process because it causes non-uniformity of the color. US Patent No. 2. In such a process, Nozzles for absorbing the coating liquid are provided on both edges of the web in the width direction, and the nozzles have an L-shaped co-pipe structure, and the outer periphery of No. 1R9 and No. 33 is A method and apparatus are disclosed in which a spray or jet stream of a diluent/solvent is supplied from a central part and a coating liquid is sucked together with the diluent/solvent from a central part.

[Purpose of the invention]

It is an object of the present invention to provide an improved coating method that does not involve removing the thick film coating solution using a nozzle or the like as described above and does not generate a thick film part at the edge of the image in the width direction. purpose.

The present invention also aims to provide an improved coating method that allows stripe coating.

[Structure and operation of the invention]

The object of the present invention is to provide a method of applying the coating liquid to the web by supplying the coating liquid so that a pool of liquid is formed just before the contact point between the parr rotating once and the continuously running web. This is achieved by a coating method characterized in that a blade is provided in contact with a part of the surface of the rotating par at a position apart from the web to partially adjust the coating amount.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the content of the present invention will be explained in more detail in comparison with the prior art based on the accompanying drawings.

FIG. 7 is a schematic diagram of a par coating apparatus disclosed in Japanese Unexamined Patent Publication No. 13-22 and μ3.

In Figure 7, l is a wire parr or a groove cutting parr,
It is rotated in the same direction as the continuously running web λ. μ is a bar support member that is provided over the entire length of the parl 1, and has the function of preventing the parr 7 from being bent and serving as a liquid supply device for supplying the coating liquid 3 to the parr 7.

That is, the coating liquid 3 is supplied from a liquid supply port j provided on the par support member into the liquid supply guide groove 7 formed between it and the weir member T, and is pulled up by the par rotating once. At this time, it is applied to the web λ.

The coating liquid 3 is measured at the contact area between the web λ and the par 7, and only the desired coating amount is applied to the web λ,
The remaining liquid flows down to form a liquid pool 1 together with the newly supplied coating liquid 3. Therefore, in a steady state, the coating liquid 3 is applied to the web λ via the liquid pool t. When the coating liquid 3 was applied to the web λ from the liquid pool t in this manner, it was surprisingly observed that the surface properties of the coating film were improved compared to the conventional method. Moreover, since Perl has both the function of transferring and applying the coating liquid onto the web and the function of measuring the desired amount of coating liquid, the entire device does not need to be attached to a container, making effective use of space. Not only is it possible to do this, but it is also easier to set and operate various conditions.

A conventional method for preventing thick coating of the edges of such a coating method is to scrape off excess liquid on the edges of the support with a metal doctor or the like before the drying process.

In order to completely dry thickly coated areas, methods such as blowing heated air onto thickly coated areas to forcefully dry them are used in addition to normal drying. The latter has problems such as scratches on the surface of the support due to contact between the two, and the latter requires a large-scale device and its operation is very troublesome.

Therefore, as shown in Figure 2, by inserting a thin base material lO between the support and the applicator at the edge of the support, the amount of thick coating at the edge has been reduced (wiper one type). Even with this method, there were problems such as poor durability because the coating was still a little thick and the base material was constantly being rubbed by the support and the bar. The thickness and material of the base material io used in this method are not particularly limited.

FIG. 3 is a sectional view when the blade /l is attached to the percoater in the present invention, and lλ is a blade holder. Figure μ is a perspective view when the blade is attached.

/3 indicates that it is not coated. That is, the third
In the figures and reference figures, a blade /l that contacts a part of the surface of the rotating bar l is provided at a position apart from the web λ, and the liquid supply to the support body is partially stopped only at the part of the blade /l. be able to. Therefore, the blade part can be left uncoated. In reality, the liquid pool is elongated in the direction of the support due to the effect of the liquid pool described above, so that the uncoated width becomes narrower than the blade width. This width varies depending on the physical properties of the coating liquid used, the running speed of the support, etc.

By using this blade, it is possible to completely prevent thick coating by leaving the ears of the support uncoated.

It has also been found that stripe coating is also possible by using the blade of the present invention.

That is, by attaching a blade wider than the width of the uncoated area to the area to be left uncoated, stripe coating can be performed to leave the target area uncoated by the desired width. Figure 1 shows a schematic diagram of stripe coating using a blade.

The material of the blade used in the present invention is not particularly limited. There are no particular restrictions on the thickness or shape of the Mayu blade as long as it can fit within the coater without coming into contact with the main support. It has been found that the same effect can be obtained by scraping off the coating liquid by bringing the blade 11 into contact with the bar as shown in FIG.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples.

Example 1 To wood pulp beaten to Canadian freeness 300σ (LBKP), sodium stearate was added per weight of bone-dry pulp, and then aluminum sulfate was added to wood pulp (LBKP) beaten to Canadian freeness 300σ.
, jtt4. Polyamide polyamine shrimp chlorhydrin (product name Kaimen 117 manufactured by Dick Percules)
By adding o, res, and 0.3% of alkyl ketene dimer (trade name: Acopel, Dick Vercules Co., Ltd.) per bone dry pulp weight, the basis weight was 1 sOfi/m2 using a normal papermaking method. The paper was made as follows. Next, calcium chloride was applied to the base paper to a thickness of 1/4 mm, depending on the surface size, and after drying, the thickness was adjusted to 1/40 mm using a calender. The back side of this base paper has a density of approximately 00230g/cr.
IL3 polyethylene is coated to a thickness of about 0.33-terres, and the surface is coated with titanium oxide with a density of about O1 containing 1 cent by weight of titanium oxide.
A long flexible support for photographic paper with a thickness of λ3oB and a width of 1700cm was obtained by coating polyethylene with a thickness of about 0.JO,m. The coating liquid (Table 7) was applied at a coating rate of 1jO1rL/min with a wire per coating device shown in Fig. 3 and Fig. μ/7?
pAcc was applied to L2.

Table 1 Here, stainless steel was used as the wire par and wire, the diameters of which were set to /2.7 mm and 0° ortn, respectively, and the wires were rotated at a circumferential speed equal to the coating speed. Moreover, polytetrafluoroethylene was used for the par support member.

In this embodiment, the blade // has a width of soH.
A polyethylene sheet with length 217111 and thickness 100ByH has the same width and thickness J! I used Ott@'s polyester holder/2 book sandwich structure.

After drying the coating film, the colloidal silica spear contained in the coating film was calibrated using a fluorescent X-ray measuring device, and the coating amount (vertical axis) was normalized to the width direction of the support (horizontal axis). Figure 7 is a plot of the above.

Comparative Example 1 A coating solution having the same composition as shown in Table 1 was applied onto the back side of the same long flexible support for photographic paper as in Example 1 using the conventional wire coater coating device shown in FIG. 7m2 at JOz/min) Apply AOC to the skin.

The wire par and application conditions were also the same as in Example 1, but 1
In this comparative example, the blade according to the present invention was not used.

After drying the coating film, Fig. r showing coating amount data similar to Fig. 7 was obtained. Comparing FIG. 7 and FIG. 1, it is confirmed that according to the present invention, no thick film portions are formed at the edges in the width direction.

Example 2 A coating solution having the same composition as shown in Table 7 was applied to the back side of the same long flexible support for photographic paper as in Example 1 using the wire coater of the present invention shown in the figure at a coating speed of 1jOTrL/. pAcc was applied in minutes/rlL2. The coating conditions were exactly the same as in Example 1 except for the installation position of the blade l/ in the width direction of the web λ.

When the coating amount distribution in the width direction of the support was measured in the same manner as in Example 1, it was confirmed that the width of the uncoated portion was about 0 mm.

〔Effect of the invention〕

According to the present invention, it is possible to prevent the formation of thick coated film portions on both edges in the width direction as described in the embodiments.

In the production of recording materials that involve coating and drying processes.

This reduces drying load, improves yield, and streamlines maintenance work.

Further, by appropriately selecting and setting the dimensions, number, and widthwise positions of the blades//, it is possible to perform stripe coating with a high degree of freedom.

[Brief explanation of drawings]

Figures 1 and 2 are schematic diagrams of conventional par coating equipment;
1 and 2 are schematic diagrams of a par coating apparatus showing an embodiment of the present invention. 1 and 2 are both schematic diagrams of a par coating apparatus showing another embodiment of the present invention. FIGS. 7 and 7 are diagrams showing example data. l...Applicator roll λ...Web 3...Coating liquid μ...Par support member j...Liquid supply port t...Weir member j...Liquid pool//...Blade 12 ...Blade Holder Patent Applicant Fuji Photo Film Co., Ltd. 3- (aim? 7allall) i * # (4 trout 1 n 1 book) 1t Voluntary procedure amendment April 1999 to the Commissioner of the Japan Patent Office t l, Incident display Showa! 2 years old patent application No. 1221t 2, title of the invention Coating method 3, relationship with the amended case 4IiP pestle applicant address 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Name (52
0) Fuji Photo Film Co., Ltd. Telephone (406) 253
7 4. Subject of amendment: ``Physical support'' in the ``Detailed Description of the Invention'' column of the specification + ``Fluorescent X-ray measuring device'' on page 9, line 9 of page 2111, to be amended to ``Fluorescent X-ray measuring device.'' .

Claims (1)

[Claims] In a method of applying a coating liquid to the web by supplying the coating liquid so as to form a liquid puddle immediately before the contact portion between a rotating par and a continuously running web, A coating method characterized in that a blade is provided at a position that contacts a part of the surface of the rotating par to partially adjust the coating amount.