JP2995623B1 - Surface treated steel sheet with excellent heat release properties - Google Patents

Abstract

A surface-treated steel sheet that can be used repeatedly and is useful for a release material having excellent heat resistance, release properties, surface smoothness, and thermal properties (thermal conductivity, linear expansion coefficient, etc.). Offer. SOLUTION: When a contact angle is measured at a steel sheet surface temperature of 180 ° C. using a gear oil of viscosity grade ISO VG460 for a surface-treated steel sheet in which a resin film is formed on a steel sheet or a plated steel sheet. A surface-treated steel sheet having an excellent heat release property, wherein the contact angle of the gear oil is 15 ° or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated steel sheet exhibiting good releasability even when exposed to high temperatures and having excellent heat releasability. The surface-treated steel sheet of the present invention is used for hot pressing during the manufacturing process of a printed circuit board, in order to prevent the mold and the copper foil on the printed circuit board from being in close contact with each other, or when hot-pressing a plurality of printed circuit boards at once. It is useful as a release material used for preventing copper foils from adhering to each other between layers. In addition, as a highly oil-repellent steel sheet,
It can also be used for various applications.

[0002]

2. Description of the Related Art Copper-clad laminates are known as printed wiring boards. The copper-clad laminate is manufactured by laminating a copper foil on a prepreg obtained by impregnating a base material such as paper or glass cloth with a thermosetting resin, and pressing and pressing with a press. For example, in the case of a double-sided copper-clad laminate, contact is made in the following order: mold of press machine-copper foil-prepreg-mold plate-prepreg-copper foil-mold of press machine. At this time,
In order to prevent the unevenness of the mold surface from being transferred to the copper foil or to prevent the mold and the copper foil from sticking together, a member called a release material is interposed between the mold and the copper foil. Be mounted.

[0003] The properties required of the release material include good releasability, no contamination of the copper foil, and the ability to keep the copper foil surface smooth (the surface roughness of the release material does not transfer to the copper foil. Or that the surface properties of the mold material do not transfer to the copper foil), and excellent heat resistance. One of the required characteristics is that the thermal expansion coefficient is substantially the same as that of the copper foil so that the positional relationship between the copper foil and the release material does not shift during pressurization and heating. Furthermore, when performing a multi-layer press, it is desired that the release material has good thermal conductivity. This is because heat is quickly transmitted to each laminated plate, and the pressing time can be reduced. Recently, there has been a demand for using a release material repeatedly to eliminate waste of resources.

[0004] Release materials that have been used so far include:
A release film made of a non-adhesive resin such as a fluororesin,
Examples include metal foil (aluminum foil or the like) coated with a release agent, release paper, and a mirror-finished stainless steel plate. However, these release materials have various problems in view of the required characteristics. That is, the release film, the release metal foil, and the release paper have insufficient flatness and cannot be applied when the copper foil is required to have a high degree of smoothness. In addition, there is a problem that it is thin and the handling workability is not good. Moreover, since it is assumed to be disposable, there is no device for reusing it. On the other hand, a mirror-finished stainless steel plate has excellent surface smoothness, but requires a polishing and cleaning step for reuse, leading to an increase in the cost of the release material.

[0005]

Therefore, the present invention can be used repeatedly and has excellent heat resistance, releasability, surface smoothness, thermal properties (thermal conductivity, coefficient of linear expansion, etc.). The task was to provide a surface-treated steel sheet that can be used as a release material.

[0006]

That is, the surface-treated steel sheet of the present invention having excellent heat-releasing properties is a surface-treated steel sheet in which a resin film is formed on a steel sheet or a plated steel sheet. A resin, a phenol resin, a polyimide resin, a polyamide imide, a ketone resin, a wholly aromatic polyester, an unsaturated polyester resin, or a silicone resin, and a viscosity grade of ISOVG460 When the contact angle is measured at a steel sheet surface temperature of 180 ° C. using the above gear oil, the gist is that the contact angle of the gear oil is 15 ° or more. The present inventors have found that the oil repellency of the resin film at a high temperature greatly affects the releasability of the release material, and the oil repellency is reproduced by the value of the contact angle under the above specific conditions. Since it was also found that it was possible to grasp the characteristics well, the above requirements were made essential.

[0007] The above resin film is JIS
It is preferable that a pencil scratch value (pencil hardness) obtained when a test machine method of a pencil scratch test specified in K5400 is performed is 2H or more. Pencil hardness is 2
If the value is smaller than H, it is difficult to maintain the smoothness of the copper foil.

[0008] JIS B 060 for the above resin film
The arithmetic average surface roughness (Ra) measured according to 1.
Preferably it is 5 μm or less. If the surface of the release material is rough, it may be transferred to a copper foil and an accurate printed circuit may not be formed.

[0009] It is a preferred embodiment of the surface-treated steel sheet of the present invention that the resin film contains a silicone resin and / or a fluororesin as a releasing agent and a surface roughening agent. It is more effective for improving moldability and preventing copper foil contamination. Further, in order to exhibit good characteristics as a release material, the amount of the resin film adhered is 0.5%.
It is preferable that it is ８8.0 g / m ² .

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The surface-treated steel sheet of the present invention is obtained by forming a resin film on a steel sheet or a plated steel sheet. When used as a release material, the aluminum plate has high thermal conductivity and the heat of the press die is transmitted quickly to the laminate, which is preferable for thermal efficiency.However, the linear expansion coefficient is larger than that of the copper foil, Is not preferable because of misalignment. The steel sheet has a moderately good thermal conductivity and a linear expansion coefficient of 12.5.
× 10 ^−6, which is close to the coefficient of linear expansion of the copper foil of 17 × 10 ⁻⁶ , so that there is no inconvenience that the copper foil and the release material are displaced. As the steel sheet, a stainless steel sheet having excellent corrosion resistance or a steel sheet other than the stainless steel sheet can be used as it is or after being plated. Plating is performed by a known method using a single metal or various alloys. The plating method is not particularly limited. Zn-plated steel sheets and Zn alloy-plated steel sheets are preferable because of their good properties. When using a plated steel sheet, before providing the resin film on the plating layer,
Chromate treatment may be performed. This is because the presence of the chromate film improves the adhesion to the resin film and also imparts a rust-preventive effect.

The surface-treated steel sheet of the present invention must have a resin film having oil repellency at a high temperature. The present inventors have found that the oil repellency of the resin film at a high temperature has a great effect on the releasability of the release material, and that the oil repellency is reproducible depending on the value of the contact angle under specific conditions. This is because it has been found that it can be grasped well.

The contact angle of the resin film is measured under the following conditions. The viscosity grade IS used to make the droplets
OVG460 gear oil. It is considered that the viscosity of the gear oil affects the contact angle, and the higher the flash point, the better the safety. Therefore, gear oil of the above viscosity grade is used. For example, "Daphne Super Gear Oil 460" manufactured by Idemitsu Kosan Co., Ltd. can be used.
0 ℃ 30.85mm ² at 459.9mm ² s, 100 ℃ in
s, flash point 274 ° C, density (15 ° C) 0.9028,
The total acid value is 0.38 mg KOH / g. The contact angle measurement temperature is 180 ° C. That is, the measurement is performed in a state where the surface temperature of the surface-treated steel sheet indicates 180 ° C. Drops are formed on the resin film surface with gear oil, and the contact angle is measured with a contact angle meter (for example, “CD-DT · A type” manufactured by Kyowa Interface Chemical Co., Ltd.).

In the present invention, the contact angle of the gear oil must be 15 ° or more. If the contact angle is less than 15 °, oil repellency is not exhibited, and a release material having poor releasability is not preferred.

[0014] The above resin film is JIS
It is preferable that a pencil scratch value (pencil hardness) obtained when a test machine method of a pencil scratch test specified in K5400 is performed is 2H or more. Pencil hardness is 2
If it is smaller than H, the resin film is likely to be damaged,
This flaw may be undesirably transferred to the copper foil.

Regarding the above resin film, JIS B 060
The arithmetic average surface roughness (Ra) measured according to 1.
Preferably it is 5 μm or less. If the surface of the release material is rough, it may be transferred to a copper foil and an accurate printed circuit may not be formed.

The main component of the resin film is an organic resin. When the surface-treated steel sheet of the present invention is used as a release material, an organic resin having excellent heat resistance is used because a high-temperature environment occurs during hot pressing. Specific examples include epoxy resins, phenol resins, polyimide resins, polyamide imides, ketone resins such as polyether ether ketone, wholly aromatic polyesters, unsaturated polyester resins, silicone resins, and the like. Known crosslinking agents known to be combined with these resins may be added. Since a dense film is formed by crosslinking the polymer chains in the resin, it is possible to improve the film hardness.

In order to enhance the releasability of the resin film, it is preferable to add a release agent as a component of the film. As the release agent, a silicone resin or a fluorine resin is used. This is for reducing the surface energy of the resin film and improving the oil repellency. The amount of the release agent is 0.5 to 10% by weight in the film.
Is preferred. If the amount of the release agent is too small, the releasability is not exhibited. On the other hand, if the amount is too large, the release agent is transferred from the resin film to the copper foil side, which is not preferable because ink is repelled during circuit printing.

Further, in order to enhance the releasability, it is preferable to include a surface roughening agent having a function of roughening the surface of the film in the film. The film surface is too rough and Ra is 0.5
It is not preferable that the thickness be more than μm, but if the film surface is finely roughened, the releasability becomes better. As the surface roughening agent, a particulate inorganic additive such as SiO ₂ , Al ₂ O ₃ , and MgO can be used.

The adhesion amount of the resin film is 0.5 to 8.0 g /
m ² is preferable. If the amount of adhesion is small, the unevenness of the steel sheet base cannot be smoothed by the resin film,
Irregularities may be transferred to the copper foil. In addition, the releasability and corrosion resistance become insufficient. If it is within the above range, the resin film is formed on the hard steel plate with an appropriate amount of adhesion,
Unevenness of the mold located under the copper foil and prepreg (15
程度 80 μm) is not transferred to the resin film of the release material via the prepreg or the copper foil. However, when the amount of the resin film attached exceeds 8.0 g / m ² , the influence of the binding force of the steel sheet does not reach the film surface, and the unevenness of the mold material is transferred to the resin film, and the release material can be reused. May disappear.

The surface-treated steel sheet of the present invention is prepared by preparing a resin film composition obtained by mixing a resin film constituent component with a steel sheet or a plated steel sheet, and applying a known method such as a dipping method, a roll coater method, a knife coater method, and a spray method. It can be manufactured from a load by applying by a coating method and heat-solidifying the film.

The surface-treated steel sheet of the present invention is useful as a release material for producing a copper-clad laminate. It can be used in place of the conventionally used mirror-finished stainless steel plate or release film, and can be used over and over again. In order to obtain a laminate using a release material, a copper foil and a prepreg or a mold material are laminated, and between a mold and a copper foil, or one copper foil for a laminate and another copper foil for a laminate adjacent thereto. Pressing may be performed with a release material interposed therebetween.

[0022]

EXAMPLES The present invention will be described in more detail with reference to the following examples. However, the following examples do not limit the present invention, and all modifications that can be made without departing from the spirit of the present invention are included in the present invention. .

Example 1 A steel sheet was an electrogalvanized steel sheet (20 g / m ^{2 of} Zn adhesion) subjected to chromate treatment (20 g / m ^{2 of} adhesion of Cr).
The thickness was 0.8 mm). Tables 1 to 3 show all the experimental Nos. About resin film formulation, contact angle, pencil hardness,
The arithmetic average roughness Ra is shown. In the table, the base resin of the resin film is an epoxy resin (A), a polyimide resin (B), a phenol resin (C), a ketone resin (D),
One of the silicone resins (E) was used. The release material used was a silicone resin (a) or a fluororesin (b), and was blended so as to be 0 to 15% by weight in the film. Surface roughening agents include Al ₂ O ₃ , SiO ₂ ,
Using any of MgO, the weight in the film is 0 to 20.
% By weight. The coating weight of the film was varied between 0.25 and 15 g / m ² as shown in the table.
An isocyanate-based cross-linking agent was added as necessary for adjusting conditions such as oil repellency, pencil hardness, and Ra.

[Test Method] The test method used in the following examples is as follows.

(1) Contact Angle In a state where the surface temperature of the surface-treated steel sheet is 180 ° C., droplets are formed on the resin film surface with a gear oil (“Daphni Super Gear Oil 460” manufactured by Idemitsu Kosan Co., Ltd.) The contact angle was measured using "CD-D T / A type" manufactured by Interface Chemistry.

(2) Surface Roughness Surface Roughness Profiler "Surfcom 554" manufactured by Tokyo Seimitsu Co., Ltd.
Using "A", the arithmetic average surface roughness Ra was determined in accordance with the method specified in JIS B0601.

(3) Pencil hardness The pencil scratch value (pencil hardness) when the coating film was scratched was measured according to the tester method of the pencil scratch test specified in JIS K 5400.

(4) Release Property Between the upper and lower molds of the hot press, a release material-prepreg powder-
The layers were laminated in the order of copper foil (35 μm) -prepreg powder-release material, pressed at 30 kgf / cm ² , and kept at 180 ° C. for 60 minutes. Thereafter, the mixture was cooled to room temperature, the mold was opened, and the release material and the laminate of copper foil and prepreg were peeled off. Whether the prepreg powder was adhered to the surface of the release material was visually observed and evaluated according to the following criteria. The prepreg powder was prepared by impregnating a glass cloth with an epoxy resin, and then drying and semi-curing the glass cloth to a size of 2 to 5 mm. The evaluation criteria are shown below. ◎: no adhesion ○: slight adhesion △: less than 10% of attached powder ×: 10% or more of attached powder

(5) Repeat Release Property The above operation was repeatedly performed using the same release material, and the point at which the prepreg powder adhered to the release material was defined as the limit (number of times) of repetitive use.

(6) Transfer Resistance A release material-copper foil (35 μm) is placed between the upper and lower molds of the hot press.
m)-prepreg-mold material-copper foil (35 µm)-prepreg powder-release material laminated in order and pressurized.
Hold for minutes. Thereafter, the mixture was cooled to room temperature, and the release material and the laminate were separated. The unevenness of the mold material was visually observed for transfer on the surface of the release material, and evaluated according to the following criteria. ：: no transfer ○: slight transfer △: transfer area less than 10% ×: transfer area 10% or more

(7) Copper Foil Contamination After a press test was carried out in the same manner as in (6), the laminate was immersed in ethanol, pulled up and visually observed for the wet state of the copper foil surface. Whether or not the mold material contaminated the copper foil was evaluated according to the following criteria. ◎: Wet area 100% ○: Wet area 99% or more and less than 100% △: Wet area 95% or more and less than 99% ×: Wet area less than 95%

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

Example 2 In order to examine the effects of the contact angle, the film hardness, and the arithmetic average surface roughness Ra on the performance as a release material, Table 4 shows the results of Example Nos. 1 to 9 and the results of Comparative Examples 33 to 34 and Reference Examples 38 to 42 are summarized. In Comparative Examples 33 to 34 in which the oil contact angle is smaller than 15 °, the releasability is poor. Reference example no. Nos. 38 to 40 and Ra with a large Ra.
41 to 42 show particularly poor transfer resistance.

[0036]

[Table 4]

Example 3 In order to study the amount of the resin film deposited and the type of the base resin, Table 5 of the present invention Example No. 28-32 and 10-14, and Reference Example Nos. The results of 51 to 52 are summarized. It was found that when the amount of adhesion was large, the releasability and transfer resistance tended to deteriorate. All of the base resins A to E showed good characteristics.

[0038]

[Table 5]

Example 4 The type and amount of the release agent were examined, and the results are shown in Table 6. Comparative Example No. In the case of 35 to 37, any properties such as release property and transfer resistance are inferior, but if the release agent is too much,
Poor stain resistance to copper foil (Reference Examples No. 44, 4
5, 43). The release agent showed good characteristics for both a and b.

[0040]

[Table 6]

Example 5 The type and amount of the surface roughening agent were examined, and the results are shown in Table 7.
It was shown to. Reference Example No. with small amount of surface roughening agent. 46-4
No. 8 is inferior in repetitive release property and transfer resistance.
However, as the amount of addition increased, the properties tended to decrease overall. Each of the surface roughening agents showed good characteristics.

[0042]

[Table 7]

[0043]

The surface-treated steel sheet of the present invention has an oil-repellent resin film formed on the surface of the steel sheet or the plated steel sheet, and is excellent in heat releasability, surface hardness and smoothness. Therefore, it can be used as a release material when pressing a laminate such as a printed wiring board. In particular, the surface-treated steel sheet of the present invention is excellent in heat resistance, mold release property, transfer resistance, etc., and is different from a conventional mold release material such as a mirror-finished stainless steel sheet or an aluminum foil coated with a mold release agent. Since it can be used repeatedly without special processing, it is a useful invention in terms of cost reduction and resource protection. The surface-treated steel sheet of the present invention can be applied to various fields as an oil-repellent steel sheet in addition to the release material.

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Tomio Kajita 1 Kanazawacho, Kakogawa City, Hyogo Prefecture Kobe Steel, Ltd. Inside the Kakogawa Works (72) Inventor Hideki Nakamura 1 Kanazawacho, Kakogawa City, Hyogo Prefecture Kobe Steel, Ltd. Inside the Kakogawa Works (72) Inventor Kenki Masuda 1 Kanazawa-cho, Kakogawa City, Hyogo Prefecture Kobe Steel Works, Ltd.Kakogawa Works (72) Inventor Tetsuo Ono 260, Roppo-cho, Inage-ku, Chiba City, Chiba Prefecture (56) References JP-A-9-53026 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B32B 15/08 B05D 7/14 B29C 43/32

Claims (6)

(57) [Claims] 1. A surface-treated steel sheet in which a resin film is formed on a steel sheet or a plated steel sheet, wherein the resin film is an air-treated steel sheet.
Poxy resin, phenol resin, polyimide resin, polya
Midimide, ketone resin, wholly aromatic polyester,
Any of unsaturated polyester resin and silicone resin
The contact angle of the gear oil was 15 when the contact angle of the gear oil was measured at 180 ° C. using a gear oil of viscosity grade ISO VG460. ° or higher, a surface-treated steel sheet with excellent heat release properties. 2. The resin film according to JIS K5
The surface-treated steel sheet excellent in heat release resistance according to claim 1, wherein a pencil scratch value obtained by performing a pencil scratch test method specified in 400 is 2H or more. 3. An arithmetic average surface roughness (Ra) of the resin film measured according to JIS B 0601 is 0.5 μm.
The surface-treated steel sheet having excellent heat release properties according to claim 1 or 2, which is: 4. The surface-treated steel sheet having excellent heat-releasability according to claim 1, wherein the resin film contains a silicone resin and / or a fluororesin as a release agent. 5. The surface-treated steel sheet according to claim 1, wherein the resin film contains a surface roughening agent. 6. The method according to claim 1, wherein the resin film has an adhesion amount of 0.5 to 8.
Excellent surface treated steel sheet in heat releasing property according to any one of claims 1 to 5 is 0 g / m ^2.