JPH0563232B2 - - 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.

[Conventional technology]

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 a method of forming a monomolecular layer of amphiphilic molecules, for example, as described by Langmiur et al. (Langmuir−Blodgett). “Physical Reuiew”
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 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 1980, 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 palmitic acid dissolved in volatile solvents 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 monomolecular film (agglomerated film) 6,
A monomolecular film 9 is formed on the surface of a substrate 8 guided by a guide roller 7 provided in water. In this case, if a monomolecular film is formed when the substrate is pulled up, a B-type film is formed when the A-type film is pulled in. 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 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 is wetted with the lower layer liquid, such as water, which may be preferable 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.
If a B-type film is to be formed, there is a possibility that a B-type film will be formed when the substrate is drawn into water, so special measures should be taken to limit the range in which the monomolecular layer can migrate to prevent this from occurring. I need to cheat.

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 provide 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 have found that the above object can be achieved by using a "two-roll" method, and have achieved the present invention. Ta.

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 developed on a lower layer liquid is rotated horizontally, and a portion of the solid monomolecular film is is pulled up along with an appropriate amount of lower layer liquid by a first rotating roll immersed in the liquid, and is brought into close contact with a second rotating roll placed close to above the first roll with a suitable small gap. This monomolecular film forming method is characterized in that the monomolecular film is transferred onto a moving web while forming a liquid pool between the web and the web.

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 amphiphilic molecules, when used as a protective layer,
tridecanoic acid, myristic acid, pentadecanoic acid,
Straight-chain fatty acids with 13 to 21 carbon atoms such as palmitic acid, margaric acid, stearic acid, nonadecanoic acid, and arachidic acid, or these Li, Na, K, Mg, Ca,
Salts such as Ba are used. Generally, pure water or an aqueous solution of an inorganic salt is used as the lower layer liquid. A preferable lower layer liquid contains divalent metal ions such as Ca ²⁺ , Cd ²⁺ , Ba ²⁺ , Mg ²⁺ and the like, and has its pH adjusted by adding carbonic acid or sodium hydrogen carbonate.

The monolayer formed on the water surface is then compressed and guided to the application area. 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 monomolecular film layer 6.

In the application area, a first rotary roll 10 is installed with its rotation axis set horizontally, with a part of it immersed in the liquid, and a first rotary roll 10 is installed close to above with a suitable small gap maintained. Two rotating rolls 11 are provided parallel to the rotating roll 10, and the web-like substrate 8 is continuously run in the direction of the arrow. The first rotating roll 10 is made of stainless steel or the like that has an affinity with the lower liquid,
By rotating in the direction of the arrow, only the solid monomolecular film 6 is transferred to the substrate 8 from the lower layer liquid surface together with an appropriate amount of the lower layer liquid, via the upper liquid surface of the first rotating roll and the liquid pool surface, and is deposited on the substrate. A monomolecular film 9a is formed. At that time, the surface speed of the first rotating roll V ₁
It is desirable to keep the speed as low as possible to maintain the liquid film on the roll surface and the liquid pool. Further, depending on the conditions, once the liquid puddle is formed, even if the rotation of the first rotating roll is stopped, the liquid film and the liquid puddle on the roll surface may be maintained. The solid monomolecular film transfer process of the present invention described above is described in the third step.
Compared to the conventional method shown in the figure, in the conventional method, the solid monomolecular film is transferred on the lower liquid surface, and
While the size of the liquid pool in the transfer section is sufficiently large, in the present invention, the transfer of the solid monomolecular film is performed in the liquid pool above the first rotating roll. Since the size of the liquid pool is also small, 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, it can be understood that the lower the speed of the first rotating roll, the greater the above-mentioned suppressing effect.

In the embodiment illustrated in FIG. 1, the diameter of the first rotating roll 10 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 a relatively small diameter are used in this way, the width of the base becomes wider and the roll as a whole becomes correspondingly longer, which may cause problems due to roll deflection. It is desirable to use a backup made of easy-to-use material. On the other hand, the second rotating roll 11
The diameter may be approximately the same as the diameter of the first rotating roll, but is preferably about 10 mm to 100 mm in order to prevent deflection.

In the case of a vapor-deposited tape, the substrate 8 is, for example, a polyethylene terephthalate film coated with Co-Ni.
A vapor-deposited magnetic recording medium or the like having a ferromagnetic thin film on which a system alloy is vapor-deposited is used, and a protective layer made of a monomolecular film of saturated fatty acid on the ferromagnetic thin film is formed by the above-described operation.

Substrates used in the present invention are not limited to those mentioned above, but may also be magnetic recording media having other types of ferromagnetic thin films, such as thin films formed by electrolytic plating or electroless plating. Furthermore, it may be made of not only a magnetic recording medium but also other materials. Furthermore, if necessary, a multilayer consisting of a desired number of monomolecular layers can be formed by repeating the above operations.

In the case shown in Fig. 1 above, the polar group of the monomolecular film attached to the substrate was an A-type film (Fig. 4), but as shown in Fig. 2, the rotation of the second rotating roll 11 was If it is reversed and the running direction of the base 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 situation is very different from the case of FIG. 1. 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 U ₁ of the first rotating roll is set as high as long as the liquid film on the roll is not disturbed. On the other hand, the diameters of both rolls are also different from those shown in FIG. The first rotating roll has a relatively large diameter of about 50 mm to 200 mm in order to stably obtain a high surface speed, and the second rotating roll has a diameter of 50 mm, which is the same as the first rotating roll.
~200mm is desirable.

[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 first rotating roll 10 is a stainless steel roll with a diameter of about 20 cm, and the second rotating roll 11 is a stainless steel roll with the same diameter.The vapor-deposited film is run in close contact with the second rotating roll 11, and both A liquid pool (bead) was created in between and the monomolecular film was transferred from the water surface to the film surface to continuously form a protective layer consisting of a palmitic acid monomolecular film. In this case, the rotation speed V ₁ of the first rotating roll is 10 r.
pm, the rotational speed V ₂ of the second rotating roll is 100 rpm, and the running speed of the tape is 6.3 m/min to form a good protective layer.

[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 the drawing]

FIG. 1 is an explanatory diagram of one embodiment of the present invention (rotating in opposite directions), and FIG. 2 is an explanatory diagram of another embodiment of the present invention (rotating in the same direction). Fig. 3 is an explanatory diagram of an example of the conventional technology, Fig. 4 is a principle diagram of A-type membrane, and Fig. 5 is B-type membrane.
It is a principle diagram of a form membrane. 1...Tank, 2...Lower liquid (aqueous layer), 3...
Nozzle, 4... Monomolecular tube, 5... Cylinder, 6
... solid monomolecular film (agglomerated film), 7 ... guide roller, 8 ... substrate, {9, 9a, 9b} ... monomolecular film, 10 ... first rotating roll, 11 ... second
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 developed on a lower layer liquid is rotated with the axis of rotation set horizontally; is pulled up together with an appropriate amount of the lower layer liquid by a first rotating roll immersed in the liquid, and is brought into close contact with a second rotating roll that is placed close to above the first roll with a suitable small gap maintained. A method for forming a monomolecular film, characterized in that the monomolecular film is transferred onto a moving web while forming a liquid pool between the web and the web. 2. The monomolecular film forming method according to claim 1, wherein the first roll surface and the moving web move in opposite directions in a portion where a liquid pool is formed. 3. The monomolecular film forming method according to claim 1, wherein the first roll surface and the moving web move in the same direction in a portion where a liquid pool is formed.