JPH0563231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for continuously forming a monomolecular film of amphipathic molecules on a web-like substrate or on a layer provided on a web-like substrate.

[Prior Art] Conventionally, various methods have been used to form thin films of organic compounds on substrates such as glass, metal materials, metal vapor deposited films, etc. One of these methods is to form a monomolecular layer of amphiphilic molecules. For example, the method is Langmuir-Blodgett. "Physical Review", 51, 664 (1937). In this method, a solution of a saturated fatty acid, which is an amphipathic molecule, dissolved in a volatile solvent such as benzene is gently dropped onto the water surface, and a monomolecular film is left behind after the solvent evaporates. After compressing the monomolecular layer thus formed to a predetermined surface pressure, the glass substrate is immersed in water and pulled up to form a monomolecular film on the glass surface. In this case, when the glass substrate is pulled up, the hydrophilic groups facing water in the monomolecular film are attached to the substrate side, and the hydrophobic groups (or lipophilic groups) are lined up on the surface, forming a monomolecular film structure, as shown in Figure 4. (referred to as A-type membrane). Further, when a glass substrate is immersed, a monomolecular film structure is formed in which the hydrophobic groups (or lipophilic groups) are attached to the substrate side and the hydrophilic groups are arranged on the surface as shown in FIG. 5 (referred to as a B-type film). (“Thin Film Handbook”,
pp. 268-269, edited by the Japan Society for the Promotion of Science, December 1982,
Published by Ohmsha Co., Ltd.).

Monomolecular layers produced by such a method have recently come to be used as insulating layers in fields such as electronics, and various improvements have been proposed (for example, Japanese Patent Laid-Open No. 52-98038).

In addition, the applicant has applied this method to a magnetic recording medium in which a thin ferromagnetic alloy film has been formed on a support by vapor deposition or electrolytic plating to protect a monomolecular film of saturated fatty acid or its metal salt. It was proposed to provide it as a layer (Special Publication No. 56-30609).

In these improved methods, for example, as shown in Figure 3, saturated fatty acids such as stearic acid and valmitic acid dissolved in a volatile solvent such as benzene and chloroform are added to the surface of the lower liquid (aqueous layer) 2 in the tank 1. The solution is dropped to form a monomolecular layer of saturated fatty acids on the water surface, and the monomolecular layer 4 is formed by suitable compression means such as a cylinder 5 partially immersed below the water surface.
is compressed to form a solid film (agglomerated film) 6, and a monomolecular film 9 is formed on the surface of a substrate 8 guided by guide rollers 7 provided in water. in this case,
If a monomolecular film is formed when the substrate is pulled up, an A-type film is formed, and a B-type film is formed when the substrate is pulled up. The monomolecular layer deposited on the substrate and spilled out is intercalated by supplying the fatty acid solution from the nozzle.

[Problems to be Solved by the Invention] The above technology is a major advance compared to the conventional batch method in that it continuously forms a solid film on the lower liquid (aqueous phase), but it is not suitable for industrial production. From this point of view, when making an A-type film, for example, there is a drawback in that the moving speed of the substrate must be extremely slow during the transfer process of the monomolecular film onto the substrate. In other words, when making an A-type film, if the pulling speed of the substrate is increased, the lower layer liquid will also be pulled up, and this will get under the monomolecular film.
This is because this evaporation is inhibited by the monomolecular layer and is very slow, and even after complete evaporation, defects occur in the density of the monomolecular film that is formed.

Furthermore, in these conventional methods, since the substrate must be drawn into the lower layer liquid once, the entire substrate becomes wet with the lower layer liquid, such as water, which may be undesirable depending on the type of substrate.
Further, there are problems such as drying time and effort.

In some cases, a monomolecular layer may also be deposited on the back surface of the substrate, for example by a pulling method.
When forming a B-type film, there is a possibility that a B-type film will be formed when the substrate is drawn into water, so special measures are taken to limit the range in which the monomolecular layer can migrate to prevent this from occurring. There is a need.

Therefore, an object of the present invention is to provide a method for forming a monomolecular film on a substrate at high speed without causing the above-mentioned problems.

Another object of the present invention is to propose a method for forming a monomolecular film on a substrate without immersing the substrate in water.

[Means for Solving the Problems] As a result of various studies, the present inventors found that the above object can be achieved by utilizing the principle of the roller coating method, and were able to obtain the present invention.

That is, the present invention provides a method for forming a monomolecular film of amphiphilic molecules on a web-like substrate, in which a solid monomolecular film spread on a lower layer liquid is rotated horizontally, and one of the solid monomolecular films is part is pulled up along with an appropriate amount of lower layer liquid by a rotating roll immersed in the liquid,
The solid monomolecular film is transferred to the web-like substrate while forming a liquid pool between the web-like substrates that are continuously running in a substantially horizontal direction with a suitable small gap maintained close to the top of the rotating roll. This is a monomolecular film forming method characterized by the following.

The present invention will be described below with reference to the case where a protective layer is provided on a vapor-deposited magnetic recording medium, but the present invention is not limited to this only, and can of course be applied to the formation of monomolecular films in electronics and other fields.

FIG. 1 shows an example of the present invention, in which a solution of amphiphilic molecules dissolved in a volatile catalyst is dropped from a nozzle 3 into a lower liquid (aqueous layer) 2 in a tank 1, and a solution of amphiphilic molecules dissolved in a volatile catalyst is dropped onto the lower liquid level. to form a monolayer 4 of amphiphilic molecules.

As volatile solvents, hexane, chloroform, dichloromethane, benzene, etc. are used, and as amphipathic molecules, when used as a protective layer, tridecanoic acid, syristinic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, Carbon number 13-21 such as nonadecanoic acid, arachidic acid, etc.
linear fatty acids or these Li, Na, K,
Salts such as Mg, Ca, Ba, etc. are used. Generally, pure water or an aqueous solution of an inorganic salt is used as the lower layer liquid. Commonly used lower layer liquids are Ca ²⁺ , Cd ²⁺ ,
It contains divalent metal ions such as Ba ²⁺ and Mg ²⁺ , and its pH has been adjusted by adding hydrochloric acid, sodium hydrogen carbonate, etc.

Next, the monolayer formed on the water surface is compressed and guided to the coating castle. For this purpose, a cylinder 5 made of a hydrophobic material such as Teflon or polyethylene or a material such as Pyrex glass or an aluminum alloy is partially immersed in water and rotated in the direction of the arrow to remove only the monomolecular layer 4 on the surface. is sent to the application area and compressed to form a solid film layer 6.

In the coating area, a rotating roll 10 is installed with its rotating shaft set horizontally, with a part of it immersed in the liquid, and a guide roll 11 is installed close to the top of the rotating roll 10 with a suitable small gap maintained. , 12, the web-like substrate 8 is caused to run continuously in substantially parallel manner. The rotating roll 10 is made of stainless steel or the like that has an affinity for the lower layer liquid, and by rotating it in the direction of the arrow, it pulls up the solid monomolecular layer 6 along with an appropriate amount of the lower layer liquid along the roll surface, and guides it along the guide rolls 11 and 12. A liquid pool is formed between the web-like substrate 8 and the web-like substrate 8 that moves closely above the rotating roll 10, and solid single molecules are transferred from the lower layer liquid surface through the liquid surface on the rotating roll 10 and the liquid pool surface. Only the film 6 is transferred to the substrate 8, and a solid monomolecular film 9- is formed on the substrate.
form 1. At this time, it is desirable to keep the surface speed V ₁ of the rotating roll 10 as low as possible to maintain the liquid film on the roll surface and the liquid pool.
Further, depending on the conditions, after a carrier liquid pool is formed, even if the rotation of the rotary roll 10 is stopped, the liquid film and the liquid pool on the roll surface may be maintained. Comparing the solid monomolecular film transfer process of the present invention described above with the conventional method shown in FIG. In contrast, in the present invention, the solid molecular film is transferred in a liquid pool above the rotating roll 10, so a negative pressure due to gravity acts inside the liquid pool, and the size of the liquid pool is small. Therefore, the tendency of the lower layer liquid to be pulled up to the substrate from the liquid pool is suppressed, and it is thought that this makes it possible to transfer the monomolecular film at high speed. Moreover, in that case, the lower the speed of the rotating roll 10, the greater the above-mentioned suppressing effect.

In the embodiment illustrated in FIG.
The diameter of 0 is preferably about 5 mm to 50 mm. If it is less than 5 mm, it will be difficult to transfer at high speed, and if it is more than 50 mm, it will be difficult to maintain a stable liquid film and liquid pool on the roll surface. Since rolls with relatively small diameters are used in this way, the width of the base becomes wider and the length of the rolls becomes correspondingly longer, which may cause the rolls to bend or cause problems. It is desirable to back it up with a slippery material such as Teflon.

In the case of a vapor-deposited tape, the substrate 8 is, for example, a vapor-deposited magnetic recording medium having a ferromagnetic thin film formed by vapor-depositing a Co-Ni alloy on a polyethylene terephthalate film, and the saturated fatty acid on the ferromagnetic thin film is A protective layer consisting of a monomolecular film of is formed.

Substrates used in the present invention are not limited to those described above, and may be magnetic recording media having other types of ferromagnetic thin films, such as thin films formed by electrolytic plating or electroless plating. often,
Furthermore, not only magnetic recording media but also other materials may be used.

Also, if desired, heating means can be used in the application area to evaporate the monolayer of solvent and assist in forming a solid monolayer.

Furthermore, by repeating the above operations, a multilayer consisting of a desired type of monomolecular layer can be formed.

Furthermore, if the speed of the rotating roller is increased, the monomolecular layer on the lower liquid level can be compressed, and other compression members such as the cylinder 5 can be blown away in some cases.

The diameter of the rotating roll 10 should be as small as possible; for example, the width of the base should be 50 to 100 cm.
In this case, the diameter of the roll is preferably about 15 to 25 cm.

In the case of Fig. 1 above, the polar substrate of the monomolecular film attached to the substrate was an A-type film (Fig. 4);
If the rotation of the second rotating roll 11 is reversed as shown in FIG. 2 and the running direction of the substrate 8 is in the direction of the arrow, a B-type film (FIG. 5) can be formed. In this case, since the base body and the first rotating roll move in the same direction at the part where the base body leaves the liquid pool, the first rotating roll moves in the same direction.
The situation is very different from the case shown in the figure. That is, in order to suppress the transfer of the lower layer liquid to the substrate 8 in FIG. 2, it is desirable that the surface speed V ₁ of the rotating roll be as high as possible as long as the liquid film on the roll is not disturbed.

On the other hand, the diameter of the roll is different from that shown in FIG. 1, and is preferably a relatively large diameter of about 50 mm to 200 mm in order to stably obtain a high surface speed.

[Example] Next, an example in which the present invention is applied to a case where a protective layer is provided on a vapor-deposited magnetic tape will be described.

A polyethylene terephthalate film with a thickness of 25 μm and a width of 50 cm was placed in a vacuum evaporation apparatus, and a film having a composition of 75% Co and 25% Ni was deposited onto the film to a thickness of 0.3 μm in a vacuum degree of 5.0 + 10 ^-6 Torr from an evaporation source filament. It was vapor-deposited so that it became thick.

A solution of 0.005 g of palmitic acid dissolved in 100 cc of benzene is dropped onto the water surface of tank 1 of the apparatus shown in Figure 1 to form a monomolecular layer, and compressed with a Teflon cylinder 5 to form a solid monomolecular layer. And so.

The rotating roll 10 is a stainless steel roll with a diameter of about 20 cm, and the vapor-deposited film is continuously run on the rotating roll 10 by guide rolls 11 and 12 with a slight gap between the two. ) and transferred the monomolecular film from the water surface to the film surface to continuously form a protective layer consisting of a palmitic acid monomolecular film. In this case, a good protective layer can be formed when the rotation speed V ₁ of the rotating roll is 10 rpm and the running speed of the tape is 6.3 m/min.

[Effects of the Invention] According to the present invention, a monomolecular film can be formed on a substrate at high speed without involving the lower layer liquid using the Langmiure method, and the monomolecular film can be formed by submerging the substrate in water. Because it is done without drawing in,
A desired monomolecular film can be formed without causing phenomena such as the substrate becoming wet with water or the monomolecular film adhering to the back layer of the substrate.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one aspect of the monolayer forming method of the present invention, FIG. 2 is an explanatory diagram showing another aspect of the present invention, and FIG. 3 is an explanatory diagram showing one aspect of the conventional monolayer forming method. The explanatory diagrams shown in FIGS. 4 and 5 are explanatory diagrams showing the principle of monomolecular film formation. 2... Lower layer liquid, 3... Nozzle, 4... Monomolecular film, 5... Cylinder, 6... Solid monomolecular film, 8...
...Substrate, 9,9-1... Monomolecular film, 10... Rotating roll.

Claims (1)

[Claims] 1. A method for forming a monomolecular film of amphiphilic molecules on a web-like substrate, in which a solid monomolecular film spread on a lower layer liquid is rotated with the axis of rotation set horizontally. A portion of the substrate is immersed in the liquid and pulled up together with an appropriate amount of the lower layer liquid, and placed between web-like substrates that run continuously in an approximately horizontal direction with a suitable small gap maintained close to the top of the rotating roll. A method for forming a monomolecular film, comprising transferring the solid monomolecular film onto the web-like substrate while forming a liquid pool. 2. The monomolecular film forming method according to claim 1, wherein the rotating roll and the web-like substrate move in opposite directions in the portion where the liquid pool is formed. 3. The monomolecular film forming method according to claim 1, wherein the rotating roll and the web substrate move in the same direction in the portion where the liquid pool is formed.