JPS62158034A - Metallic-foil composite body - 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] <Industrial Application Field> The present invention is capable of accurately reading the shapes and colors of characters, symbols, figures, etc. written on metal foil through a transparent polyimide resin layer, and performing secondary processing. The present invention relates to a metal foil composite that can be effectively used in such cases.

<Prior art and its problems> Polyimide resin is an “invention” (March 1985 issue, p.
As can be seen in 72), it is an engineering plastic with excellent heat resistance and electrical insulation properties, and is widely used in electronic circuit boards, laminates, heat-resistant electrical insulation materials, aircraft soft structural materials, OA equipment interior mechanical parts, etc. has been done. These uses include those that undergo further secondary processing in a composite system with metal foil, and those that are used in combination with other parts. Therefore, in such a case, it is advantageous in terms of processing accuracy if the characters, symbols, figures, etc. written on the metal foil can be used as they are.

Many examples of polyimide resins are known (°“
Japan Adhesive Association Magazine” Vol, 20 No. 9 P2B (
(1984)) Most of the products are semi-transparent, and no transparency data is available.

A few examples of polyimide adhesives are “plastic°”
Vol, 3B, No, 9. P53 (1985)
However, in this case as well, the product has a wall thickness of 50IL11, and the light transmittance is at a low level of 72%.

All polyimide resins with low light transmittance are colored deep yellow, and do not have excellent transparency, especially for yellow or pink printed matter.

<Object of the invention> The object of the invention is to provide characters, symbols,
A metal foil composite with heat resistance and insulation resistance, which forms a heat-resistant resin layer with excellent transparency on the surface of figures, etc., and makes it possible to advantageously develop secondary processing in the next process. It is about providing.

<Structure of the Invention> Conventionally, it has been widely practiced to coat metal products with polyimide resins having excellent heat resistance and insulation resistance, and it is also a well-known fact that polyimide resins are combined with metal foils.

However, commonly used polyimide resins are
Both have low transparency and are colored deep yellow, so even if the wall thickness is thinned, there is almost no transparency for yellowish printed matter, and pink and orange, blue and green There were problems such as no color difference being observed between the two systems.

When developing metal foil composite products, the inventors of the present invention conducted extensive studies with the aim of advantageously developing secondary processing using characters, symbols, figures, etc. printed in various colors on the surface of the foil. As a result, by using polyimide resin with performance limited to these surfaces within a limited wall thickness range,
The inventors have discovered that the object can be achieved and have completed the present invention.

According to the present invention, a polyimide resin having a light transmittance of 80% or more is coated on the surface of the metal foil on which the printed matter is printed, with a thickness of 10% or more.
A metal foil composite characterized by being laminated to a thickness of 0 gm or less is provided.

The present invention will be explained in detail below.

Practically, the polyimide resin used in the present invention is preferably a polyimide resin whose main component is a reaction product of a tetracarboxylic acid dianhydride having a specific cyclohydrocarbon structure and an aromatic diamide. As a specific example, as the tetracarboxylic acid dianhydride, cyclobutane-1,2;3
, 4-tetracarboxylic acid dianhydride, bicyclo(3,3
, 0) Octane-2,3; 6,8-tetracarboxylic acid.
2 anhydride, etc., and aromatic diamides include diaminodiphenyl ether, diaminodiphenylmethane, 2
．． 2-bis(4-(4-aminophenoxy)phenyl)
Examples include propane. Other components may be used in combination as long as transparency is not lost.

Polyimide resin obtained by the reaction of these compounds can be applied by directly applying a varnish in the form of a boriamic acid produced by a synthetic reaction to a metal foil, followed by heating and curing, or by applying a varnish that has been formed in advance. Possible methods include laminating a polyimide resin film, boriamix acid varnish, and metal foil, and curing the adhesive by heating.

On the other hand, the transparency of the obtained polyimide resin is naturally affected by its wall thickness. Generally speaking, if the wall thickness is thin, even if the parallel light transmittance is high, as the wall thickness increases, the transparency will decrease. There is a tendency for this to decrease. Since polyimide resin is an expensive material, it is desired to use it as thinly as possible, and 110
If the wall thickness is less than 0IL, it can be used for very fine figures, characters, etc.
It has been found that the shapes and colors of symbols etc. can be read and are economically advantageous.

Further, the light transmittance is preferably 80% or more. 80%
This is because if it is less than that, transparency will decrease and it will be impossible to achieve the object of the present invention.

On the other hand, the metal foil used in the present invention includes copper, aluminum, iron, stainless steel, titanium, soot, etc., as well as alloys with other metals containing these materials as main components.
Generally, it means a wall thickness up to about 1501L.

<Examples> Hereinafter, the present invention will be specifically described according to Examples and Comparative Examples. The measurement method followed the conditions below.

(1) Light transmittance: Measured using a digital colorimetric colorimeter manufactured by Suga Test Instruments. In the case of any polyimide resin,
A film having a wall thickness of 50 mm was formed, and the light transmittance was measured using this as a sample.

(Example 1) Yellow magic ink (oil-based ink) was used on the surface of 5O9-430 shown in Table 2, with a thickness of 1 mm and a gap of 1 mm.
Mark the base grain pattern with
C. for 1 hour to form a polyimide resin layer with a thickness of 30 points. The yellow printed matter (base grain pattern) was clearly distinguishable, and the transparency was good as shown in Table 2. Note that the light transmittance of a polyimide resin film with a thickness of 50 gm molded from the same boriamic acid was 80% or more in all cases.

Table-1 Table-2 (Example 2) on the surfaces of aluminum and copper foils shown in Table 3.

Using pink, orange, blue, and green magic ink,
In the same manner as in Example 1, the thickness lI and the gap 1+*
A base grain pattern is marked with m, and polyimide resin layers with various thicknesses shown in Table 3 are applied thereon using the polyimide resin A film used in Example 1 and the polyimide resin varnish A having the same composition as shown in Table 3. was formed. As shown in Table 3, all the results were clearly distinguishable and had good transparency.

Table 3 (Comparative Example 1) As in Example 1, a base grain pattern was drawn on a 5OS-430 foil, and then the boriamix acid varnish shown in Table 4 was applied over it, and polyimide resins of various thicknesses were coated. As shown in Table 5, these polyimide resins in which a layer was formed had a light transmittance of less than 80%, and the transparency was poor, making it impossible to read the printed matter.

Table-4 Table-5 (Comparative Example 2) A similar base grain pattern was created on the same metal foil as in Example 2, and the boriamic acid varnishes C and D used in Example 1 were prepared.
As shown in Table 6, polyimide resin layers each having a thickness of 120 μm were formed using the following methods. Because of their thick walls, all of them had poor transparency. It is possible to obtain a metal foil composite with excellent transparency that allows the identification of the There are effects such as being made possible by relationships.

/′

Claims (1)

[Claims] (1) A metal foil composite, characterized in that a polyimide resin having a light transmittance of 80% or more is laminated to a thickness of 100 μm or less on a metal foil surface with a printed matter on the surface.