JPS62225344A - Multilayer film and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a multilayer film containing a heat- or radiation-curable resin and a method for producing the same.

(Conventional technology) Multilayering of coating films is one of the technologies to ensure comprehensive performance by having each layer maintain a separate function.
Multilayer films are used in many fields, such as coating metal structures for the purpose of corrosion protection, insulation, coated magnetic recording media, etc.

However, since most of them use thermosetting resins, there are many restrictions on handling, such as the need for a high-temperature process called baking.

In addition, in the field of coated magnetic recording media such as magnetic tapes and magnetic disks, a thermoplastic resin or thermosetting resin layer is formed on a substrate such as a polyester film, and one or more magnetic layers are roughly coated on top of it. There are also attempts to do so.

(Problem to be Solved by the Invention) However, when such a thermosetting resin layer is overcoated on the base layer, the base layer melts out when the thermosetting resin layer is applied and the base layer is damaged. This often results in inconveniences such as peeling off from the surface of the substrate or impairing the surface properties of the upper layer. In addition, when forming one or more thermosetting resin layers such as magnetic layers by coating, the issues are always the curing properties of the coating film and the pot life of the paint, but it is necessary to satisfy both of these at the same time. This has been difficult with conventional technology. When manufacturing ZaraNi magnetic tape, a high temperature heat treatment process is required to accelerate hardening.
After such a step, surface roughening and blocking of the magnetic layer, which is called transfer, may occur, and improvements have been desired.

The present invention has been made in order to solve the above-mentioned problems, and aims to provide a multilayer film that achieves both curability and pot life, and that can be easily and quickly formed, and a method for manufacturing the same.

[Structure of the invention] (Means and effects for solving the problems) That is, the multilayer film of the present invention is a multilayer film in which at least one layer containing a heat or radiation curable resin is formed on a substrate. A curing accelerator for the curable resin is contained in at least one layer adjacent to the curable resin-containing layer, and the method for producing the same includes at least one layer containing a heat or radiation curable resin on a substrate. The method for producing the formed multilayer film includes a step of applying and curing a paint containing this curable resin to form a curable resin-containing layer, and a step of applying and curing a paint containing a curing accelerator for the curable resin. and forming a curing accelerator-containing layer adjacent to the curable resin-containing layer.

In the present invention, when forming a paint film by coating a paint containing a curable resin on a substrate, instead of adding a curing accelerator for the curable resin to the paint, By incorporating a curing accelerator into the paint to be applied, the curing accelerator is supplied from the coating film formed first or subsequently, and the curing of the coating film is accelerated.

In the present invention, the layer containing the curing accelerator does not necessarily have to be a curable resin layer, but the coating layer adjacent to this layer must be a curable resin layer. It is possible to apply multiple layers while sequentially curing the thermosetting resin layers, or it is also possible to form a multilayer coating by combining an ultraviolet ray or electron beam curable coating and a thermosetting coating. When a curing accelerator is not required, such as an electron beam curable resin, the electron beam curable resin layer becomes a layer containing the curing accelerator of the adjacent layer.

The curable resin used to form the multilayer film in the present invention can be any resin as long as it has good film-forming properties and satisfies the intended physical properties, but it is particularly good in curability and film-forming properties. Preferred are curable resins having functional groups such as glycidyl groups, acroyl groups, and isocyanate groups.

Examples of resins having a glycidyl group include bisphenol A epoxy resin, sphenol F epoxy resin, phenol novolac epoxy resin, talesol novolac epoxy resin, alicyclic epoxy resin, triglycidyl isocyanate, and hydantoin epoxy. Heterocyclic epoxy resins, hydrogenated bisphenol A type epoxy resins, aliphatic epoxy resins such as propylene glycol diglycidyl ether and pentaerythritol polyglycidyl ether, aromatic, aliphatic or alicyclic carboxylic acids and epichlorohydrin Epoxy resin obtained by reaction with, spiro ring-containing epoxy resin,
Glycidyl ether type epoxy resin is a reaction product of an ortho-allyl-phenol novolac compound and epichlorohydrin, and glycidyl ether is a reaction product of a diallylbisphenol compound having an allyl group at the ortho position of each hydroxyl group of bisphenol A and epichlorohydrin. Cover with mold epoxy resin, etc.

Compounds with acroyl groups are cured using radiation such as ultraviolet rays or electron beams, but they usually introduce acroyl groups into oligomers (molecular weight 200 to 50,000) such as polyurethane, epoxy resins, polyesters, polyols, and polybutadiene. Preferably.

Examples of these include urethane (meth)acrylate-1~
, epoxy (meth)acrylate, polyester (meth)acrylate, polyol (meth)acrylate, polybutadiene (meth)acrylate, melamine (meth)acrylate
Acrylates include polyacetal (meth)acrylate, silicone (meth)acrylate, polyamide (meth)acrylate, and heterocycle-containing (meth)acrylate, but there are also various resins for coatings that are modified to have (meth)acryloyl groups in the molecule. It is also possible to use resins into which these are introduced, and these may be used alone or in combination.

Examples of compounds having an isocyanate group include 2.4-tolylene diisocyanate, 2.6-tolylene diisocyanate, 1.3-xylene diisocyanate, 1.4-xylene diisocyanate, 1.5-naphthalene diisocyanate, m-phenylene diisocyanate, and p-phenylene diisocyanate. -phenylene diisocyanate, methylene bis-(4-phenylisocyanate), methylene bis-(3-methyl-4
-phenyl isocyanate), 3.3'-dimethylbiphenylene diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, tremethylhexamethylene diisocyanate, lysine diisocyanate, dimer acid diisocyanate, isophorone diisocyanate, methylcyclohexane-2
, 4-diisocyanate, methylcyclohexane-2,
6-diisocyanate, 1,3-(isocyanatomethyl)cyclohexane, 4,4'-methylenebis-(cyclohexyl isocyanate), etc., but adducts of these isocyanate compounds with polyhydric alcohols, such as trimethylolpropylene, are preferable. Pantry tolylene diisocyanate adducts and the like are used.

Other examples of curable resins that can be used include melamine resins, urea resins, phenolic resins, ketone resins, furan resins, polyimide resins, unsaturated polyester resins, spiran resins, diallyl phthalate resins, and polybutadiene. Yes, but not limited to these.

These curable resins may be used alone or in combination of two or more. It is also possible to use it in combination with a thermoplastic resin to improve properties. In this case, copolymerization using a thermoplastic resin having a functional group is also possible.
It is also effective to form an interpenetrating network (IPN) structure without copolymerization.

Curing accelerators for these curable resins vary depending on the type of resin, and amine compounds, fatty acid metal salts, complex salts, and the like are often used for curing epoxy resins and isocyanates. An amine compound is used as the acrylic photocuring accelerator. Further, a radical curing agent is used for resins having unsaturated double bonds, such as unsaturated polyester resins.

In the case of a two-component catalyst, it is possible to add the catalyst components in separate layers. An example of this is an epoxy resin using a two-component aluminum chelator silanol catalyst.

Further, the curing accelerator added to the cured resin layer can also be used in common with the accelerator in the adjacent layer.

Depending on the purpose, it is also possible to use a resin that uses a Lewis acid as a curing accelerator, such as an epoxy resin or a furan resin.

It is also possible to add carbon and a non-R filler to the resin composition system of the present invention.

In particular, applying the present invention to multilayer magnetic recording media is extremely effective from the standpoint of stabilizing the process, improving characteristics, and reliability.

Furthermore, depending on the application, additives such as surfactants such as dispersants, lubricants, antistatic agents, antiaging agents, dyes, pigments, and plasticizers may be added to the multilayer film.

In the multilayer film of the present invention, a coating material containing a composition containing a curable resin mixed in an organic solvent and a coating material containing a composition containing a curing accelerator for this curable resin mixed in an organic solvent are sequentially applied to each layer as necessary. and then drying.

(Example) Next, the present invention will be explained in detail using examples.

Example 1 Benzyldimethylamine (5 phr), a curing accelerator for the second layer, was placed on a polyester film (33 μm thick).
) A 10% solution of cyclohexanone containing polyurethane resin (N-3135, manufactured by Nippon Polyurethane Co., Ltd.) was applied to a thickness of 0.5 μm using an applicator and dried.

Next, an epoxy resin (Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.) and an acid anhydride (HN-220
A toluene solution of a 1:1 mixture of 0:0: manufactured by Hitachi Chemical Co., Ltd.) was prepared. Next, this was coated on the polyurethane resin film described above to a thickness of about 3 μm and dried at 80° C. for 4 hours to produce a two-layer film.

Comparative Example 1 A two-layer film was produced in the same manner as in Example 1, except that the polyurethane resin solution used in Example 1 did not contain benzyldimethylamine.

Example 2 Dibutyltin dilaurate (DBTL) was added to the epoxy resin solution in Example 1 as a curing accelerator for the third layer.
A two-layer film was produced in the same manner as in Example 1 except that phr was added.

Next, a polyurethane resin (N
-3135> was overcoated to a thickness of 2 μm on the epoxy resin layer and dried at 60° C. for 2 hours.

Comparative Example 2 A three-layer film was produced in the same manner as in Example 2, except that the epoxy resin solution in Example 2 did not contain dibutyltin dilaurate.

Table 1 shows the state of the coating film obtained as described above.

As is clear from the table, there is a significant difference in the degree of curing between the films with and without a curing accelerator added to the adjacent layer.

(Margin below) Table-1 Example 3 Epicote 828 (trade name, Yuka Shell Epoxy Co., Ltd. 1)
io part, Chisson Knox 206 (product name, manufactured by Chisso Corporation)
40 parts, Epikote 8 which is a polyol type epoxy resin
12 (trade name, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy purpose 160), 30 parts of acetylacetonatobisdipivaloylmethanatoaluminum, and 3 parts of diphenylvinylpropenyloxysilane were mixed and applied to an aluminum plate. It was cured at 60°C for 10 hours to obtain a coating film.

Next, 5 parts of diphenylvinylpropenyloxysilane, which is one of the two-component catalyst components, was added to the resin system and dissolved in methyl ethyl ketone, and a layer of 5 μm thick was added onto the coating film.
When it was applied to a thick layer and left at 40'C for 5 hours, it was cured to form a two-layer film. Next, 5 parts of acedelacetobisdipivaloylmethanatoaluminum, which is another component of the catalyst, was added to the same resin composition system, diluted with methyl ethyl ketone, and coated again to a thickness of 3 μm to form a three-layer film. When this film was left at 40°C, it hardened to form a tough film.

In addition, in the resin system of the first layer in this example, only diphenylvinylpropenyloxysilane was added as a curing catalyst.
When it was coated on an aluminum plate, avoiding the presence of a certain amount, and left at 40° C. for 5 hours, a good coating film was not obtained.

Example 4 20 parts of Viscoat #540 (epoxy acrylate oligomer, manufactured by Osaka Organic Chemical Industry Co., Ltd.) as a binder,
60 parts of pentaerythritol tetraacrylate, polyurethane resin N-2301 (manufactured by Nippon Polyurethane Co., Ltd.) 2
0 parts, carbon black (specific surface area 700 m2/(])
20 parts to 200 parts of toluene and 2 parts of methyl ethyl ketone
00 parts and using paint conditioner 4
Spread out time. After filtering the obtained paint with a 5 μm stainless steel filter, 7 parts of benzoin ethyl ether,
10 parts of 4,4'-diethylaminobenzophenone was added and applied to a 13 μm thick polyester film by gravure coating. After drying, the coating was cured using an 80 W/CTII high pressure mercury lamp to form an undercoat with a thickness of 0.5 μm. layer(
A) was obtained.

This upper layer is coated with magnetic paint (30 parts of vinylite VAGH, Co
-T Fe20370 parts, Diocchisiftale-1 to 5
2 parts of lecithin were dissolved in 150 parts of toluene and 150 parts of methyl ethyl ketone and dispersed in a sand grinder for 2 hours.
After drying the coating film, the surface was smoothed using a super calender and left at room temperature for one week to obtain a magnetic recording medium. A part of this magnetic recording medium was cut out and tested for solvent resistance by immersion in acetone, and it was confirmed that it was sufficiently cured as it was not attacked by acetone.

Comparative Example 3 The same magnetic paint as in Example 4 was applied directly to a polyester base without using the undercoat layer (A) used in Example 4, and when cut out and subjected to an acetone immersion test, the coating film changed color in spots. However, it swelled and was insufficiently cured.

[Effects of the Invention] As explained above, according to the present invention, the curing accelerator is not added to the curable resin layer to be cured by the curing accelerator, but is added to the layer adjacent thereto. In addition to being easy to handle, it is possible to efficiently produce multilayer films soaked in curability with high productivity.

Claims (9)

[Claims] (1) In a multilayer film in which at least one layer containing a heat- or radiation-curable resin is formed on a substrate, a curing accelerator for this curable resin is contained in at least one layer adjacent to the curable resin-containing layer. A multilayer film characterized by: (2) The multilayer film according to claim 1, wherein all the multilayer films are layers containing heat or radiation curing resin. (3) The multilayer film according to claim 1 or 2, wherein at least one layer contains a dye or pigment. (4) The multilayer film according to claim 1 or 2, wherein at least one layer contains an inorganic or organic filler. (5) Claim 4 in which the inorganic filler is magnetic powder
Multilayer film described in section. (6) The multilayer film according to claim 4, wherein the inorganic filler is carbon. (7) The multilayer film according to any one of claims 1 to 6, wherein the heat- or radiation-curable resin is a resin having at least one of a glycidyl group, an acroyl group, and an isocyanate group. (8) Claim 1 that the multilayer film is a magnetic recording medium
Multilayer film described in section. (9) In a method for producing a multilayer film in which at least one layer containing a heat or radiation curable resin is formed on a substrate, a curable resin-containing layer is formed by applying and curing a paint containing this curable resin. and a step of applying and curing a paint containing a curing accelerator for the curable resin to form a curing accelerator-containing layer adjacent to the curable resin-containing layer. Method for manufacturing multilayer films.