WO2011111826A1

WO2011111826A1 - Mold release film and method for manufacturing mold release film

Info

Publication number: WO2011111826A1
Application number: PCT/JP2011/055798
Authority: WO
Inventors: 洋祐中尾; 弘丈松本; 靖志五藤; 雅弘土谷
Original assignee: 積水化学工業株式会社
Priority date: 2010-03-12
Filing date: 2011-03-11
Publication date: 2011-09-15
Also published as: CN102791480A; CN102791480B; JPWO2011111826A1; JP5837976B2; TWI540051B; JP2015083379A; KR101873071B1; TW201144072A; KR20130043623A; JP5719290B2

Abstract

Disclosed is a mold release film, which has excellent mold releasability and excellent conforming characteristics to the substrate surface, and which can suppress flow out of an adhesive in heat press molding. The mold release film has a surface layer, and a mold release layer is observed only in a region within a thickness of 50-300 nm from the surface of the surface layer.

Description

Release film and method for producing release film

The present invention relates to a release film that is excellent in releasability, excellent in followability to a substrate surface, and can suppress the flow of adhesive during hot press molding.

In the manufacturing process of a printed wiring board, a flexible printed board, a multilayer printed wiring board, and the like, a release film is used when a copper-clad laminate or a copper foil is hot-pressed on a board via a prepreg or a heat-resistant film. In the manufacturing process of the flexible printed circuit board, when the cover lay film is hot-press bonded to the flexible printed circuit board body on which the copper circuit is formed with a thermosetting adhesive or a thermosetting adhesive sheet, Release films are widely used to prevent the hot press plate from adhering.

For the release film, for example, heat resistance that can withstand hot press molding, release properties for printed wiring boards and hot press plates, ease of disposal, and the like are required. In addition, non-contamination to the copper circuit is also important for improving the product yield during hot press molding.

Conventionally, as a release film, a fluorine-based film, a silicone-coated polyethylene terephthalate film, a polymethylpentene film, a polypropylene film, and the like have been used (for example, Patent Document 1).
However, the fluorine-based film is excellent in heat resistance, releasability, and non-contamination, but is expensive and hardly burns when incinerated in the disposal process, and generates toxic gas. In addition, the silicone-coated polyethylene terephthalate film and the polymethylpentene film may cause contamination of a printed wiring board, particularly a copper circuit, due to migration of a low molecular weight substance in silicone or a constituent component, and may impair quality. Moreover, a polypropylene film is inferior in heat resistance, and its mold release property is also insufficient.

In addition, release films made of polyester resins such as polybutylene terephthalate have been studied. Such release films are excellent in heat resistance, ease of disposal, and non-contamination, but release. There is room for improvement in terms of sex.

On the other hand, the applicant of the present application invented a release film composed of a polyester-based resin and a predetermined amount of polypropylene as a release film having excellent non-contamination properties and excellent release properties. Is disclosed. Here, in order to further improve the releasability of the release film as described in Patent Document 2, as described in Patent Document 2, the release film is subjected to heat treatment. Is effective.
However, such heat treatment is performed at a high temperature and requires a long time, which may increase the cost. Furthermore, since the release film subjected to heat treatment is reduced in flexibility as a whole film, the followability to the unevenness of the substrate surface (embedding property) is reduced, for example, a void is generated during hot press molding, The adhesive formed on the coverlay film may flow out to the electrode portion of the flexible printed circuit board, which may cause problems such as an obstacle to the plating treatment of the electrode portion. Therefore, there is a demand for a release film having a further excellent releasability without impairing the ability to follow irregularities on the substrate surface.

JP-A-5-283862 JP 2009-132806 A

An object of this invention is to provide the release film which is excellent in mold release property, is excellent in the followable | trackability to a substrate surface, and can suppress the outflow of the adhesive agent at the time of hot press molding.

The first aspect of the present invention is a release film having a surface layer, wherein the release treatment layer is observed only in a region from the surface layer to a thickness of 50 to 300 nm.
2nd this invention is a release film which has a surface layer containing a polyester-type resin, Comprising: In the area | region from the surface of the said surface layer to thickness 1 micrometer, it is with respect to the surface among the carbonyl groups contained in the said polyester-type resin. The release film has a proportion of carbonyl groups oriented in parallel to 45% or more.
The third aspect of the present invention is a release film having a surface layer, wherein the surface layer has a surface roughness Rz of 250 to 450 nm, a surface distortion Rsk of +0.3 to +1.1, and a surface edge Rku of The release film is 5-11.
The present invention is described in detail below.

The inventors of the present invention have the following three surface layers: (1) a surface layer where a predetermined release treatment layer is observed, and (2) a ratio of carbonyl groups oriented parallel to the plane satisfies a predetermined range. The release film having any one of the surface layer and (3) the surface roughness Rz, the surface distortion Rsk, and the surface edge Rku satisfying a predetermined range does not impair the followability to the substrate surface. The present inventors have found that an excellent release property can be exhibited at the same time while suppressing the flow of the adhesive during hot press molding, and have completed the present invention.

The release film of the first aspect of the present invention has a surface layer, and the release treatment layer is observed only in a region from the surface of the surface layer to a thickness of 50 to 300 nm.
In the present specification, the release treatment layer means a layer having an appearance different from that of other regions in the surface layer and excellent in releasability. Further, in the present specification, the release treatment layer includes not only a case where the entire layer has a uniform appearance, but also a portion having a part having a different appearance as a whole. This includes cases where

In the release treatment layer, a different pattern is observed as compared with other regions in the surface layer. Examples of the pattern observed in the release treatment layer include a streak pattern parallel to the surface. Although the pattern observed in the other area | region in the said surface layer is not specifically limited, For example, sandy patterns, spiral patterns, and other non-uniform patterns are mentioned.
1, 2 and 3 are cross-sectional views schematically showing a part of the surface layer of the release film of the first invention. 1, 2 and 3, the upper side is the surface of the surface layer, that is, the surface of the release film. A part of the surface layer shown in FIGS. 1, 2, and 3 has a release treatment layer 1 on the surface side where a streak pattern parallel to the surface is observed. In FIG. 1, the other region 2 in the surface layer has a sand-like pattern, and in FIG. 2, the other region 2 ′ in the surface layer has a spiral pattern, The other region 2 ″ in the surface layer has other non-uniform patterns.

Since the release treatment layer observed in this way has a high density and acts as a barrier layer, the surface layer can suppress the penetration of the epoxy adhesive, for example, when in contact with the epoxy adhesive. it can. Therefore, the release film of the first aspect of the present invention can exhibit excellent release properties.
The method of observing the release treatment layer is not particularly limited, but a method of observing a cross section obtained by cutting in the thickness direction using a microtome or the like with a transmission electron microscope is preferable. Moreover, as a method for observing the release treatment layer, a method of observing a cross section obtained by cutting in the thickness direction using a microtome or the like with a polarizing microscope, an atomic force microscope, or the like may be used. The transmission electron microscope (TEM) is not particularly limited, and examples thereof include a Hitachi transmission electron microscope (model H-9500, manufactured by Hitachi High-Technology Corporation). The microtome is not particularly limited, and examples thereof include a sliding microtome (model SM2000-R, manufactured by Ikeda Rika Co., Ltd.).

In addition, the release film of the first aspect of the present invention has a release treatment layer only in the region from the surface layer surface to a thickness of 50 to 300 nm. Unlike the conventional release film, the flexibility of the entire film can be maintained even if it has excellent release properties. Therefore, the release film of the first aspect of the present invention has excellent followability to the substrate surface, and can suppress the flow of adhesive during hot press molding.

When the thickness of the release treatment layer is less than 50 nm from the surface of the surface layer, the surface layer cannot sufficiently suppress the penetration of the epoxy adhesive when contacting the epoxy adhesive, for example. The release film thus obtained has a low release property. When the thickness of the release treatment layer exceeds 300 nm from the surface of the surface layer, the resulting release film is less flexible, the followability to the substrate surface is lowered, and the adhesive flows out during hot press molding. Is difficult to suppress.
The thickness of the release treatment layer is preferably 70 nm or more from the surface of the surface layer, and preferably 250 nm or less from the surface of the surface layer.

The release film of the second aspect of the present invention has a surface layer containing a polyester resin.
In the release film of the second aspect of the present invention, in the region from the surface layer to the thickness of 1 μm, the proportion of carbonyl groups oriented parallel to the surface of the carbonyl groups contained in the polyester resin is 45%. That's it.
In the present specification, the ratio X of carbonyl groups oriented parallel to the surface of the carbonyl groups contained in the polyester resin is calculated by the following formula (1).
X = {A / (A + B)} × 100 (1)

In formula (1), A represents the peak intensity of the carbonyl group oriented in parallel to the plane obtained by X-ray analysis, and B represents the perpendicular to the plane obtained by X-ray analysis. It represents the peak intensity of the oriented carbonyl group. In this specification, being parallel or perpendicular to the surface means being parallel or perpendicular to the surface of the release film.

When the ratio of the carbonyl group oriented parallel to the plane is within the above range, the release film of the second aspect of the present invention can exhibit excellent release properties. This is presumed to be because the hydrophobicity of the surface of the surface layer is increased by increasing the proportion of carbonyl groups oriented parallel to the surface in the region from the surface of the surface layer to a thickness of 1 μm.

Further, in the release film of the second aspect of the present invention, the region in which the ratio of the carbonyl group oriented parallel to the surface is within the above range is a region from the surface of the surface layer to a thickness of 1 μm. Unlike conventional release films that have been subjected to heat treatment or the like to improve moldability, the flexibility of the entire film can be maintained even with excellent release properties. Therefore, the release film of the second aspect of the present invention is excellent in followability to the substrate surface, and can suppress the flow of adhesive during hot press molding.

When the ratio of the carbonyl group oriented in parallel to the plane is less than 45%, the hydrophobicity of the surface of the surface layer is lowered, so that the obtained release film has a reduced release property.
The proportion of carbonyl groups oriented parallel to the plane is preferably 55% or more.

The upper limit of the proportion of carbonyl groups oriented parallel to the plane is not particularly limited, and may be 100%, but is preferably 90% or less. When the proportion of carbonyl groups oriented parallel to the plane exceeds 90%, for example, the amount of work energy of friction treatment when producing a release film becomes too large, so that the obtained release film is wrinkled. Damage such as scratches may occur.
The proportion of carbonyl groups oriented parallel to the plane is more preferably 70% or less.

Examples of the method for performing the X-ray analysis include a method for measuring diffraction of X-rays obliquely incident on the surface of the surface layer (In-PLane). The X-ray analysis apparatus for performing the X-ray analysis is not particularly limited, and examples thereof include a sample horizontal X-ray diffractometer for thin film evaluation (model Smart Lab, manufactured by Rigaku Corporation).

The release film of the third aspect of the present invention has a surface layer, and the surface layer has a lower limit of the surface roughness Rz of 250 nm. When the surface roughness Rz is less than 250 nm, the obtained surface layer becomes smooth, the contact area of the surface layer increases, and the releasability decreases. A preferable lower limit of the surface roughness Rz is 280 nm.
The upper limit of the surface roughness Rz is 450 nm. When the surface roughness Rz exceeds 450 nm, the resulting surface layer has unevenness. For example, when used for adherends with high fluidity or flexibility such as epoxy adhesive, contact with the adherend The area increases and the releasability decreases.

In the present specification, the surface roughness Rz means that the surface height of the surface layer is Yp1, Yp2, Yp3, Yp4 and Yp5, which are the deepest from the highest peak to the fifth highest in the reference length L, respectively. When the elevation of the valley bottom from the valley bottom to the fifth depth is Yv1, Yv2, Yv3, Yv4 and Yv5, it means a value obtained by the following formula (2), and the larger the value, the rougher the surface, A smaller value means a smoother surface as a whole.

In the surface layer, the lower limit of the surface distortion Rsk is +0.3. When the surface distortion Rsk is less than +0.3, the convex component of the obtained surface layer is decreased, the contact area of the surface layer is increased, the releasability is lowered, and the appearance of the obtained surface layer is poor. . A preferable lower limit of the surface distortion Rsk is +0.5, and a more preferable lower limit is +0.8.
The upper limit of the surface distortion Rsk is +1.1. When the surface distortion Rsk exceeds 1.1, the resulting surface layer has an increased convex component. For example, when used for an adherend having high fluidity or flexibility such as an epoxy adhesive, the adherend This increases the contact area with the material and causes a decrease in releasability.

In the present specification, the surface distortion Rsk means a value obtained by the following formula (3) when the root mean square roughness is Rq and the peak height is Yi, and is a positive value. If so, it means that there are many convex components with respect to the average line on the surface, and a negative value means there are many concave components with respect to the average line on the surface.

The surface layer has a lower limit of the surface edge Rku of 5. When the surface sharpness Rku is less than 5, the resulting convex shape of the surface layer becomes gradual, the contact area of the surface layer increases, and the releasability decreases. The preferable lower limit of the surface sharpness Rku is 6, and the more preferable lower limit is 7.
The upper limit of the surface sharpness Rku is 11. When the surface sharpness Rku exceeds 11, the resulting surface layer becomes smooth and the contact area of the surface layer increases, and the releasability decreases.

In the present specification, the surface sharpness Rku means the value obtained by the following formula (4) when the root mean square roughness is Rq and the height of the mountain is Yi, and the value is large. As the convex shape becomes sharper, the flat portion with respect to the average line increases, and as the value decreases, the convex shape becomes gentler and the flat portion with respect to the average line decreases.

In the release film of the first aspect of the present invention, in order for the release treatment layer to be observed only in the region from the surface surface to a thickness of 50 to 300 nm, for example, surface treatment such as friction treatment on the surface layer. It is preferable to carry out. Moreover, in order to make the ratio of the carbonyl group oriented parallel to the plane in the release film of the second invention within the above range, the surface satisfying the above range in the release film of the third invention Similarly, in order to impart a surface shape such as roughness Rz, it is preferable to perform surface treatment such as friction treatment on the surface layer.
The friction treatment is not particularly limited, but is preferably performed so that the work energy amount En (KJ) represented by the following formula (5) is 50 to 500 KJ.
En = (Ar × J) / (W × LS) (5)

In the formula (5), Ar represents an area (m ² ) where the friction processing device performs friction processing, J represents a work amount per unit time (KJ / min) for friction processing, and W is subjected to friction processing. Represents the width (m) of the film, and LS represents the line speed (m / min) of the film being rubbed.

In the above formula (5), the area Ar (m ² ) on which the friction processing device performs friction processing is the area of the film on which the friction processing device performs friction processing.
Further, the amount of work J (KJ / min) per unit time for the friction processing is the amount of load energy per unit time (the friction power source of the friction processing device generated by the friction processing device applying pressure to the film). It is obtained by multiplying the amount of applied load energy) and the number of times of friction treatment.
Further, the width W (m) of the film to be subjected to friction processing is the width of the film to be subjected to friction processing by the friction processing device.
Further, the line speed LS (m / min) of the film subjected to the friction treatment is a speed at which the film passes through the friction treatment apparatus.

When the work energy En (KJ) is less than 50 KJ, no release treatment layer is observed in the region from the surface surface to the thickness of 50 to 300 nm as described above, or the film is oriented parallel to the surface. In some cases, the ratio of the carbonyl group may not be within the above range, or the surface shape such as the surface roughness Rz that satisfies the above range may not be imparted, and the obtained release film It may not be possible to impart excellent releasability. When the amount of work energy En (KJ) exceeds 500 KJ, the resulting release film has reduced flexibility, followability to the substrate surface due to damage such as wrinkles and scratches, In some cases, the flow of adhesive during hot press molding cannot be sufficiently suppressed.
The friction treatment is more preferably performed such that the upper limit of the work energy amount En (KJ) represented by the above formula (5) is 300 KJ.

In the friction treatment, the fabric fiber used as the material of the surface of the friction treatment material has a preferable lower limit of tensile strength of 1.0 g / d and a preferable upper limit of 5.0 g / d. When the tensile strength of the fiber is less than 1.0 g / d, the fiber may be stretched in the friction treatment, and the fiber may adhere to the obtained release film. If the tensile strength of the fiber exceeds 5.0 g / d, the resulting release film will be damaged, such as wrinkles and scratches, and the followability to the substrate surface will be reduced, causing the adhesive to flow out during hot press molding. May not be sufficiently suppressed. The upper limit with more preferable tensile strength of the said fiber is 3.0 g / d.
In this specification, the tensile strength of a fiber means the tensile strength of a single fiber obtained by a method based on JIS-L-1095.

The fiber has a preferred lower limit of elongation of 1% and a preferred upper limit of 30%. When the elongation of the fiber is less than 1%, the fiber may be stretched in the friction treatment, and the fiber may adhere to the obtained release film. If the elongation of the fibers exceeds 30%, the resulting release film will be damaged, such as wrinkles and scratches, and the followability to the substrate surface will be reduced, allowing the adhesive to flow out sufficiently during hot press molding. It may not be possible to suppress. A more preferable upper limit of the elongation of the fiber is 29%.
In the present specification, the fiber elongation means the tensile elongation of a single fiber determined by a method based on JIS-L-1095.

Specific examples of the fiber include PET, rayon, cotton, wool, and acetate. In particular, it is possible to obtain a release film excellent in followability to the substrate surface by further suppressing damage such as wrinkles and scratches generated in the release film by performing a friction treatment. Rayon and wool are preferred because the attached fibers can be reduced.

In addition, the fabric used for the material of the friction treatment material has a preferable lower limit of the friction coefficient of 0.1 and a preferable upper limit of 0.8. If the friction coefficient of the woven fabric is less than 0.1, the release property of the obtained release film may be lowered. If the friction coefficient of the woven fabric exceeds 0.8, the resulting release film will be damaged, such as wrinkles and scratches, the followability to the substrate surface will be reduced, and the adhesive will flow sufficiently during hot press molding. May not be suppressed. The minimum with a more preferable friction coefficient of the said textile fabric is 0.3, and a more preferable upper limit is 0.7.
In this specification, the coefficient of friction of the fabric means the coefficient of friction of the fabric against a 2 mm polycarbonate plate obtained by a method according to JIS-K-7125.

The woven fabric has a preferable lower limit of the elastic modulus of 0.1 MPa and a preferable upper limit of 4.0 MPa. When the elastic modulus of the woven fabric is less than 0.1 MPa, the release property of the obtained release film may be lowered. If the elastic modulus of the woven fabric exceeds 4.0 MPa, the resulting release film will be damaged, such as wrinkles and scratches, the followability to the substrate surface will be reduced, and the adhesive will flow sufficiently during hot press molding May not be suppressed. The more preferable lower limit of the elastic modulus of the woven fabric is 0.7 MPa, and the more preferable upper limit is 3.9 MPa.
In this specification, the elastic modulus of the fabric means the hardness of the fabric obtained by a method according to JIS-K-7127.

The fabric has a preferred lower limit of tensile strength of 1.5 N / 10 mm and a preferred upper limit of 2.5 N / 10 mm. If the tensile strength of the woven fabric is less than 1.5 N / 10 mm, the fibers may be stretched in the friction treatment, and the fibers may adhere to the resulting release film. If the tensile strength of the woven fabric exceeds 2.5 N / 10 mm, the resulting release film will be damaged, such as wrinkles and scratches, and the followability to the substrate surface will be reduced, causing the adhesive to flow out during hot press molding. May not be sufficiently suppressed. The more preferable lower limit of the tensile strength of the woven fabric is 1.6 N / 10 mm, the more preferable upper limit is 2.3 N / 10 mm, and the still more preferable upper limit is 1.8 N / 10 mm.
In the present specification, the tensile strength of the fabric means the tensile strength of the fabric determined by a method according to JIS-K-7127.

The friction processing apparatus for performing the above-described friction processing is not particularly limited, and examples thereof include a polishing processing apparatus (model YCM-150M, manufactured by Yamagata Machine Co., Ltd.).

In the release film of the second aspect of the present invention, the surface layer contains a polyester resin. In the release films of the first and third inventions, the surface layer is not particularly limited, but preferably contains a polyester resin.

Hereinafter, matters common to the release films of the first, second and third inventions will be described in detail. In the present specification, when the release film of the present invention is simply referred to, it means that it corresponds to any of the first, second and third release films of the present invention.

The polyester resin is not particularly limited. By using the polyester-based resin, the obtained release film can exhibit excellent mechanical performance, in particular, excellent mechanical performance in a temperature range of about 170 ° C. in which normal hot press molding is performed. In addition, by using the polyester resin, the obtained release film reduces the environmental load during incineration and is economically advantageous. Furthermore, since the polyester resin has a small amount of low molecular weight components, the resulting release film is excellent in non-contaminating property, and the low molecular weight component bleed-out due to hot pressing causes plating defects on the electrode portion of the flexible printed circuit board. This problem can also be suppressed.

As the polyester-based resin, for example, a crystalline aromatic polyester resin is preferable.
Although the said crystalline aromatic polyester resin is not specifically limited, For example, the crystalline aromatic polyester resin etc. which are obtained by making aromatic dicarboxylic acid or its ester-forming derivative, and low molecular weight aliphatic diol react are mentioned.
As the crystalline aromatic polyester resin, a crystalline aromatic polyester resin (hereinafter referred to as “polyester”) obtained by reacting an aromatic dicarboxylic acid or an ester-forming derivative thereof with a low molecular weight aliphatic diol and a high molecular weight diol. A crystalline aromatic polyester resin having an ether skeleton in the main chain ”), a crystalline aromatic polyester resin obtained by reacting an aromatic dicarboxylic acid or an ester-forming derivative thereof with a low molecular weight aliphatic diol; Examples thereof include a crystalline aromatic polyester resin obtained by dissolving in caprolactone monomer and then ring-opening polymerization of caprolactone (hereinafter also referred to as “crystalline aromatic polyester resin having a polycaprolactone skeleton in the main chain”). .

Among them, the release film obtained is more heat resistant than when a crystalline aromatic polyester resin obtained by reacting an aromatic dicarboxylic acid or an ester-forming derivative thereof with a low molecular weight aliphatic diol is used. The crystalline aromatic polyester resin having a polyether skeleton in the main chain and the crystalline aromatic polyester resin having a polycaprolactone skeleton in the main chain are preferable because they are excellent in flexibility and releasability while maintaining the above.

Examples of the aromatic dicarboxylic acid or its ester-forming derivative include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, paraphenylene dicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, dimethyl orthophthalate, dimethyl naphthalenedicarboxylate, And dimethyl paraphenylene dicarboxylate. These may be used alone or in combination of two or more.

Examples of the low molecular weight aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and 1,5-pentane. Examples thereof include diol, 1,6-hexanediol, 1,4-cyclohexanedimethanol and the like. These may be used alone or in combination of two or more.

Examples of the high molecular weight diol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyhexamethylene glycol. These may be used alone or in combination of two or more.

More specifically, examples of the crystalline aromatic polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, butanediol terephthalate-polytetramethylene glycol copolymer. And butanediol terephthalate-polycaprolactone copolymer. These may be used alone or in combination of two or more. Among these, polybutylene terephthalate is preferable because the obtained release film is particularly excellent in non-contamination and crystallinity.

The crystalline aromatic polyester resin preferably has a melting point of 200 ° C. or higher measured using a differential scanning calorimeter.
Usually, since hot press molding is performed at less than 200 ° C., by using a resin having such a high melting point, the obtained release film does not melt even during hot press molding and has releasability. And breakage during hot press molding is suppressed. An example of the differential scanning calorimeter is DSC 2920 (manufactured by TA Instruments).

When the melting point of the crystalline aromatic polyester resin measured using a differential scanning calorimeter is less than 200 ° C., the resulting release film has low heat resistance and may melt during hot press molding. More preferably, the crystalline aromatic polyester resin has a melting point of 220 ° C. or higher measured using a differential scanning calorimeter.

The crystalline aromatic polyester resin having a melting point of 200 ° C. or higher measured using the differential scanning calorimeter is not particularly limited. For example, polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polyethylene naphthalate, polybutylene Examples thereof include phthalates and butanediol terephthalate-polytetramethylene glycol copolymers. These may be used alone or in combination of two or more. Of these, polybutylene terephthalate is preferred because the resulting release film is excellent in non-staining and crystallinity.

The surface layer may contain a stabilizer. The said stabilizer is not specifically limited, For example, a hindered phenolic antioxidant, a heat stabilizer, etc. are mentioned.
The hindered phenol antioxidant is not particularly limited. For example, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 3 , 9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxa Examples include spiro [5,5] undecane.
The heat stabilizer is not particularly limited, and examples thereof include tris (2,4-di-t-butylphenyl) phosphite, trilauryl phosphite, 2-t-butyl-α- (3-t-butyl-4- Hydroxyphenyl) -p-cumenylbis (p-nonylphenyl) phosphite, dimyristyl 3,3′-thiodipropionate, distearyl 3,3′-thiodipropionate, pentaerythryltetrakis (3-laurylthiopropio) Nate) and ditridecyl 3,3′-thiodipropionate.

The said surface layer may also contain additives, such as a fiber, an inorganic filler, a flame retardant, an ultraviolet absorber, an antistatic agent, an inorganic substance, a higher fatty acid salt, in the range which does not impair the effect of this invention.

The fiber may be an inorganic fiber or an organic fiber. The inorganic fiber is not particularly limited, and examples thereof include glass fiber, carbon fiber, boron fiber, silicon carbide fiber, alumina fiber, amorphous fiber, and silicon-titanium-carbon fiber. The said organic fiber is not specifically limited, For example, an aramid fiber etc. are mentioned.

The inorganic filler is not particularly limited, and examples thereof include calcium carbonate, titanium oxide, mica and talc.
The flame retardant is not particularly limited, and examples thereof include hexabromocyclododecane, tris- (2,3-dichloropropyl) phosphate, pentabromophenyl allyl ether, and the like.

The ultraviolet absorber is not particularly limited, and examples thereof include pt-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2,4,5-tri And hydroxybutyrophenone.
The antistatic agent is not particularly limited, and examples thereof include N, N-bis (hydroxyethyl) alkylamine, alkylallyl sulfonate, and alkyl sulfonate.

The inorganic material is not particularly limited, and examples thereof include barium sulfate, alumina, and silicon oxide.
The higher fatty acid salt is not particularly limited, and examples thereof include sodium stearate, barium stearate, and sodium palmitate.

The surface layer may contain a thermoplastic resin and a rubber component in order to modify the properties of the surface layer.
The thermoplastic resin is not particularly limited, and examples thereof include polyolefin, modified polyolefin, polystyrene, polyvinyl chloride, polyamide, polycarbonate, polysulfone, and polyester.
The rubber component is not particularly limited. For example, natural rubber, styrene-butadiene copolymer, polybutadiene, polyisoprene, acrylonitrile-butadiene copolymer, ethylene-propylene copolymer (EPM, EPDM), polychloroprene, butyl rubber Acrylic rubber, silicone rubber, urethane rubber, olefin thermoplastic elastomer, styrene thermoplastic elastomer, vinyl chloride thermoplastic elastomer, ester thermoplastic elastomer, amide thermoplastic elastomer, and the like.

The surface layer may also contain an inorganic compound having a large aspect ratio.
By including an inorganic compound having a large aspect ratio, the release film obtained has improved release properties at high temperatures, and further, additives, low molecular weight substances, etc. contained in the release film are brought to the release film surface. Bleed-out can be suppressed, and cleanliness during hot press molding is improved.
The inorganic compound having a large aspect ratio is not particularly limited, and examples thereof include layered silicates such as clay and layered double hydrates such as hydrotalcite.

The surface layer preferably has a crystallinity of 25% or less. When the crystallinity exceeds 25%, the followability of the obtained release film may be lowered. The crystallinity of the surface layer is more preferably 20 to 23%.
In the present specification, the degree of crystallinity means a value obtained from a peak intensity ratio between a crystalline part and an amorphous part obtained by an X-ray diffraction method.

The surface layer may be subjected to a heat treatment in order to further improve the heat resistance, dimensional stability, and release property of the obtained release film as long as the effects of the present invention are not impaired.
Although the method of the said heat processing is not specifically limited, For example, the method of passing a film between the rolls heated to fixed temperature, the method of heating a film with a heater, etc. are preferable.
The temperature of the heat treatment is not particularly limited as long as it is not lower than the glass transition temperature and not higher than the melting point of the resin contained in the surface layer such as the polyester resin, but a preferable lower limit is 120 ° C. and a preferable upper limit is 200 ° C. If the temperature of the heat treatment is less than 120 ° C., the effect of improving the releasability by the heat treatment may be hardly obtained. If the temperature of the heat treatment exceeds 200 ° C., the surface layer tends to be deformed during the heat treatment, and a release film may not be produced. The more preferable lower limit of the heat treatment temperature is 170 ° C., and the more preferable upper limit is 190 ° C.

Although the thickness of the said surface layer is not specifically limited, A preferable minimum is 5 micrometers and a preferable upper limit is 20 micrometers. When the thickness of the surface layer is less than 5 μm, the strength of the surface layer is impaired, and the surface layer may be destroyed at the time of hot press molding or peeling of the release film. When the thickness of the surface layer exceeds 20 μm, the obtained release film is less flexible, the followability to the substrate surface is lowered, and the flow of the adhesive during hot press molding cannot be sufficiently suppressed. is there. The more preferable lower limit of the thickness of the surface layer is 10 μm, and the more preferable upper limit is 15 μm.

The release film of the present invention may be a single-layer film or a multi-layer film having two or more layers as long as it has the surface layer.

When the release film of the present invention is a multilayer film, it may have an intermediate layer.
The intermediate layer preferably contains a polyolefin resin having a melting point of 60 ° C. or higher and lower than 130 ° C. measured using a differential scanning calorimeter.
By using the polyolefin-based resin, the obtained intermediate layer starts to soften at a temperature near the temperature at which the adhesive of the coverlay film starts to melt. Therefore, the release film having such an intermediate layer is applied to the substrate surface. It has excellent followability and has sufficient followability even with respect to a flexible printed circuit board having a fine copper circuit pitch of, for example, 100 μm or less, and can suppress the flow of adhesive.

When the melting point of the polyolefin resin measured with a differential scanning calorimeter is less than 60 ° C., the intermediate layer resin melts and stains when the release film is stored and the ambient temperature is 50 to 60 ° C. May cause blocking. When the melting point of the polyolefin resin measured using a differential scanning calorimeter is 130 ° C. or higher, the resulting release film may have a poor followability to the substrate surface. The melting point of the polyolefin resin measured by using a differential scanning calorimeter is more preferably 65 ° C. or higher and 100 ° C. or lower.

Specific examples of the polyolefin resin include polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, ethylene-methyl methacrylate copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer. And an ethylene-acrylic acid copolymer. These may be used alone or in combination of two or more. Among these, low density polyethylene, linear low density polyethylene, ethylene-methyl methacrylate copolymer, and ethylene-vinyl acetate copolymer are preferable.

The intermediate layer preferably further contains a resin having a melting point of 130 ° C. or higher measured using a differential scanning calorimeter.
When a resin having a low softening temperature such as a polyolefin resin having a melting point of 60 ° C. or higher and lower than 130 ° C. measured using the above differential scanning calorimeter is used for the intermediate layer, the release temperature depends on the pressure during hot press molding. The resin may ooze out from the intermediate layer at the end of the mold film and may contaminate the printed wiring board, the hot press plate, and the like. On the other hand, by using a resin having a melting point of 130 ° C. or higher measured using the differential scanning calorimeter, the resin oozes out from the intermediate layer generated at the end of the release film during hot press molding. Can be suppressed.
The resin having a melting point of 130 ° C. or higher measured using the differential scanning calorimeter is not particularly limited, and examples thereof include polypropylene and crystalline aromatic polyester resin.

When the intermediate layer contains a resin having a melting point of 130 ° C. or higher measured using the differential scanning calorimeter, the amount of such a resin is not particularly limited, but a preferred lower limit in the intermediate layer is 5% by weight. The preferred upper limit is 50% by weight. When the blending amount of the resin having a melting point of 130 ° C. or higher measured using the differential scanning calorimeter is less than 5% by weight, the resin stain from the intermediate layer generated at the end of the release film during hot press molding The effect of suppressing the ejection may not be sufficiently obtained. When the blending amount of the resin having a melting point of 130 ° C. or higher measured using the differential scanning calorimeter exceeds 50% by weight, the resulting release film may have a low followability to the substrate surface.

The said intermediate | middle layer may contain additives, such as a fiber, an inorganic filler, a flame retardant, a ultraviolet absorber, an antistatic agent, an inorganic substance, and a higher fatty acid salt similarly to the said surface layer.

Although the thickness of the said intermediate | middle layer is not specifically limited, A preferable minimum is 10 micrometers and a preferable upper limit is 200 micrometers. When the thickness of the intermediate layer is less than 10 μm, the intermediate layer is too thin, and when the intermediate layer is softened during hot press molding, a portion where the intermediate layer does not exist partially occurs, and the press pressure is uniformly applied to the substrate. May not be able to load. If the thickness of the intermediate layer exceeds 200 μm, the intermediate layer is unnecessarily thick, so that the resin exudation from the intermediate layer that occurs at the end of the film during hot press molding may not be suppressed. A more preferable lower limit of the thickness of the intermediate layer is 20 μm, and a more preferable upper limit is 100 μm.

The release film of the present invention preferably has a dimensional change rate of 1.5% or less when pressed at 170 ° C. with a load of 3 MPa for 60 minutes. If the dimensional change rate exceeds 1.5%, the circuit pattern of the flexible printed circuit board may be damaged during hot press molding. The dimensional change rate is more preferably 1.0% or less.
Moreover, it is preferable that the dimensional change rate of the width direction (henceforth TD) and length direction (henceforth MD) of the release film of this invention is the same direction and is equivalent grade. When the vertical and horizontal dimensional changes are different such that one (for example, MD) contracts and the other (for example, TD) expands, the release film damages the circuit pattern of the flexible printed circuit board during hot press molding. Sometimes.

Although the use of the release film of the present invention is not particularly limited, for example, the release film of the present invention is formed by hot press molding a copper clad laminate or a copper foil on a substrate via a prepreg or a heat-resistant film, When manufacturing a flexible printed circuit board or a multilayer printed wiring board, it is preferably used for preventing adhesion between the hot press board and the obtained printed wiring board, flexible printed circuit board or multilayer printed wiring board.
In addition, the release film of the present invention is obtained by bonding a coverlay film to a substrate on which a copper circuit is formed via a thermosetting adhesive by hot press molding, It is also preferred to be used for preventing adhesion with the coverlay film or adhesion between the coverlay films.
Furthermore, the release film of the present invention is also preferably used for preventing adhesion between a molding die and a mold resin when a semiconductor mold is produced by hot press molding.

The method for producing the release film of the present invention is not particularly limited, but a method in which after the film having the surface layer is formed, the surface treatment such as friction treatment as described above is performed on the surface layer is more preferable. Specifically, for example, the surface of the surface layer is subjected to a friction treatment with a friction treatment material, and the material of the surface of the friction treatment material is made of fibers having a tensile strength of 1.0 to 5.0 g / d. It is a woven fabric, and the friction treatment is preferably performed such that the work energy amount En (KJ) represented by the above formula (5) is 50 to 500 KJ.

The film forming method of the release film of the present invention is not particularly limited. For example, a water-cooled or air-cooled co-extrusion inflation method, a method of forming a film by a co-extrusion T-die method, and after producing the above surface layer, Examples thereof include a method of laminating layers by an extrusion lamination method, a method of dry lamination of the above-described surface layer film and an intermediate layer film, a solvent casting method, a hot press molding method, and the like. In particular, when the release film of the present invention is a film having a plurality of layers, a method of forming a film by a coextrusion T-die method is preferable because of excellent thickness control of each layer.

In the solvent casting method, for example, an anchor layer is undercoated on a film serving as an intermediate layer, and then a resin composition serving as a surface layer in which the polyester resin or the like is dissolved in a solvent is coated on the anchor layer. The coating film is uniformly heated and dried to form a surface layer.
Moreover, in the said hot press molding method, the film used as the said surface layer and the film used as an intermediate | middle layer are piled up and hot-press-molded, for example.

ADVANTAGE OF THE INVENTION According to this invention, the mold release film which is excellent in mold release property, is excellent in the followable | trackability to a substrate surface, and can suppress the outflow of the adhesive agent at the time of hot press molding can be provided.

It is sectional drawing which showed typically a part of surface layer of the release film of 1st this invention. It is sectional drawing which showed typically a part of surface layer of the release film of 1st this invention. It is sectional drawing which showed typically a part of surface layer of the release film of 1st this invention. It is the image obtained by observing the cross section obtained by cut | disconnecting the thickness direction using a microtome about the release film obtained in Example 1 with a transmission electron microscope. It is the image obtained by observing the cross section obtained by cut | disconnecting the thickness direction using a microtome about the release film obtained in Example 2 with a transmission electron microscope. It is the image obtained by observing the cross section obtained by cut | disconnecting the thickness direction using a microtome about the release film obtained in Example 3 with a transmission electron microscope. It is the image obtained by observing the cross section obtained by cut | disconnecting the thickness direction using a microtome about the release film obtained in Example 5 with a transmission electron microscope. It is the obtained image which observed the cross section obtained by cut | disconnecting the thickness direction using a microtome about the release film obtained in the comparative example 1 with the transmission electron microscope.

Examples of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.
In the following examples and comparative examples, “Toraysee” manufactured by Toray and “Tetron” manufactured by Teijin Fibers, which are used as the material of the surface of the friction treatment material, are PET.

Example 1
Polybutylene terephthalate (Novaduran 5010R5, manufactured by Mitsubishi Engineering Plastics Co., Ltd., melting point 224 ° C.) as the crystalline aromatic polyester resin for the surface layer, and linear low-density polyethylene (Excellen FX (CX5501) as the polyolefin resin for the intermediate layer , Sumitomo Chemical Co., Ltd., melting point 66 ° C.) and ethylene-methyl methacrylate copolymer (Aklift (WH401), Sumitomo Chemical Co., Ltd., melting point 86 ° C.) and polypropylene (PS207A, Sun Allomer Co., Ltd., melting point 160 ° C.) The film was put into an extruder and coextruded from a T-die to obtain a film having a surface layer thickness of 10 μm and an intermediate layer thickness of 80 μm. The melting point was measured using a differential scanning calorimeter (DSC 2920, manufactured by TA Instruments).

The surface of the surface layer of the obtained film was subjected to a friction treatment device (abrasion treatment device, model YCM-150M, manufactured by Yamagata Kikai Co., Ltd.) using a friction treatment material having a woven fabric composed of fibers shown in Table 1 as a surface material. Friction treatment was performed so that the amount of work energy (KJ) shown in Table 1 was obtained, and a release film was obtained.
The amount of work energy is the area Ar (m ² ) where the friction processing device performs friction processing, the amount of work J (KJ / min) per unit time for friction processing, and the width W (m) of the film subjected to friction processing. And the line speed LS (m / min) of the film subjected to the friction treatment was calculated by applying the equation (5).

The obtained release film was cut in the thickness direction using a sliding microtome (model SM2000R, manufactured by Ikeda Rika Co., Ltd.), and the cross section was obtained by using a transmission electron microscope (TEM) (model H-9500, Hitachi High Technologies). When observed by the company), the release treatment layer was observed only in the region from the surface of the surface layer to the thickness (nm) shown in Table 1. An image observed with a transmission electron microscope in Example 1 is shown in FIG. Further, the degree of crystallinity (%) of the surface layer was calculated from the peak intensity ratio between the crystal part and the non-crystal part obtained by the X-ray diffraction method.

(Examples 2 to 5)
A release film was obtained in the same manner as in Example 1 except that the material on the surface of the friction treatment material and the amount of work energy (KJ) were changed as shown in Table 1.
The obtained release film was cut in the thickness direction using a sliding microtome (model SM2000R, manufactured by Ikeda Rika Co., Ltd.), and the cross section was obtained by using a transmission electron microscope (TEM) (model H-9500, Hitachi High Technologies). When observed by the company), the release treatment layer was observed only in the region from the surface of the surface layer to the thickness (nm) shown in Table 1. FIG. 5 shows an image observed with a transmission electron microscope in Example 2, FIG. 6 shows an image observed with a transmission electron microscope in Example 3, and FIG. 6 shows an image observed with a transmission electron microscope in Example 5. This is shown in FIG. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 1.

(Comparative Example 1)
A release film was obtained in the same manner as in Example 1 except that the friction treatment was not performed.
The obtained release film was cut in the thickness direction using a sliding microtome (model SM2000R, manufactured by Ikeda Rika Co., Ltd.), and the cross section was obtained by using a transmission electron microscope (TEM) (model H-9500, Hitachi High Technologies). The mold release layer was not observed. An image observed with a transmission electron microscope is shown in FIG. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 1.

(Comparative Examples 2-3)
A release film was obtained in the same manner as in Example 1 except that the material on the surface of the friction treatment material and the amount of work energy (KJ) were changed as shown in Table 2.
The obtained release film was cut in the thickness direction using a sliding microtome (model SM2000R, manufactured by Ikeda Rika Co., Ltd.), and the cross section was obtained by using a transmission electron microscope (TEM) (model H-9500, Hitachi High Technologies). When observed by the company), the release treatment layer was observed only in the region from the surface of the surface layer to the thickness (nm) shown in Table 2. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 1.

(Example 6)
Polybutylene terephthalate (Novaduran 5010R5, manufactured by Mitsubishi Engineering Plastics Co., Ltd., melting point 224 ° C.) as the crystalline aromatic polyester resin for the surface layer, and linear low-density polyethylene (Excellen FX (CX5501) as the polyolefin resin for the intermediate layer , Sumitomo Chemical Co., Ltd., melting point 66 ° C.) and ethylene-methyl methacrylate copolymer (Aklift (WH401), Sumitomo Chemical Co., Ltd., melting point 86 ° C.) and polypropylene (PS207A, Sun Allomer Co., Ltd., melting point 160 ° C.) The film was put into an extruder and coextruded from a T-die to obtain a film having a surface layer thickness of 10 μm and an intermediate layer thickness of 80 μm. The melting point was measured using a differential scanning calorimeter (DSC 2920, manufactured by TA Instruments).

The surface of the surface layer of the obtained film was subjected to a friction treatment device (abrasion treatment device, model YCM-150M, manufactured by Yamagata Machinery Co., Ltd.) using a friction treatment material having a woven fabric composed of fibers shown in Table 3 as a surface material. Friction treatment was performed so that the amount of work energy (KJ) shown in Table 3 was obtained, and a release film was obtained.
The amount of work energy is the area Ar (m ² ) where the friction processing device performs friction processing, the amount of work J (KJ / min) per unit time for friction processing, and the width W (m) of the film subjected to friction processing. And the line speed LS (m / min) of the film subjected to the friction treatment was calculated by applying the equation (5).

The region from the surface of the obtained release film to the thickness of 1 μm is subjected to X-ray analysis using a sample horizontal X-ray diffractometer for thin film evaluation (model Smart Lab, manufactured by Rigaku Corporation). The ratio (%) of carbonyl groups oriented in parallel was determined.
In addition, the ratio (%) of the carbonyl group oriented parallel to the plane was obtained by X-ray analysis, and the peak intensity A of the carbonyl group oriented parallel to the plane was aligned perpendicular to the plane. The peak intensity B of the carbonyl group was calculated by applying the formula (1). Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 1.

(Examples 7 to 9)
A release film was obtained in the same manner as in Example 6 except that the material on the surface of the friction treatment material and the amount of work energy (KJ) were changed as shown in Table 3.
The region from the surface of the obtained release film to the thickness of 1 μm is subjected to X-ray analysis using a sample horizontal X-ray diffractometer for thin film evaluation (model Smart Lab, manufactured by Rigaku Corporation). The ratio (%) of carbonyl groups oriented in parallel was determined. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 6.

(Comparative Example 4)
A release film was obtained in the same manner as in Example 6 except that the friction treatment was not performed.
The region from the surface of the obtained release film to the thickness of 1 μm is subjected to X-ray analysis using a sample horizontal X-ray diffractometer for thin film evaluation (model Smart Lab, manufactured by Rigaku Corporation). The ratio (%) of carbonyl groups oriented in parallel was determined. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 6.

(Example 10)
Polybutylene terephthalate (Novaduran 5010R5, manufactured by Mitsubishi Engineering Plastics Co., Ltd., melting point 224 ° C.) as the crystalline aromatic polyester resin for the surface layer, and linear low-density polyethylene (Excellen FX (CX5501) as the polyolefin resin for the intermediate layer , Sumitomo Chemical Co., Ltd., melting point 66 ° C.) and ethylene-methyl methacrylate copolymer (Aklift (WH401), Sumitomo Chemical Co., Ltd., melting point 86 ° C.) and polypropylene (PS207A, Sun Allomer Co., Ltd., melting point 160 ° C.) The film was put into an extruder and coextruded from a T-die to obtain a film having a surface layer thickness of 10 μm and an intermediate layer thickness of 80 μm. The melting point was measured using a differential scanning calorimeter (DSC 2920, manufactured by TA Instruments).

Using a friction processing device (model YCM-150M, manufactured by Yamagata Machinery Co., Ltd.), the surface layer of the obtained film is a friction made of a woven fabric made of cotton as the surface material so that the work energy (KJ) shown in Table 4 is obtained. A release film having a surface roughness Rz of 250 nm, a surface distortion Rsk of +0.80, and a surface edge Rku of 8 was obtained by friction treatment with the treatment material. The surface roughness Rz, the surface distortion Rsk, and the surface edge Rku were calculated using the above formulas (2), (3), and (4), respectively. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 1.

(Example 11)
Except that the amount of work energy (KJ) was changed as shown in Table 4, the surface roughness Rz of the surface layer was 250 nm, the surface distortion Rsk was +0.30, and the surface sharpness Rku was the same as in Example 10. A release film of 5 was obtained. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 10.

(Example 12)
The amount of work energy (KJ) was changed as shown in Table 4, except that it was friction-treated with a friction treatment material with a woven fabric made of wool as a surface material instead of a friction treatment material with a woven fabric made of cotton as a surface material. In the same manner as in Example 10, a release film having a surface roughness Rz of 380 nm, a surface distortion Rsk of +0.85, and a surface sharpness Rku of 7 was obtained. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 10.

(Example 13)
The surface roughness Rz of the surface layer is the same as in Example 10, except that the friction treatment is performed using the wool woven fabric as the surface material instead of the cotton woven fabric as the surface treatment. A release film having 430 nm, surface distortion Rsk of +1.10, and surface edge Rku of 11 was obtained. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 10.

(Comparative Example 5)
A release film having a surface roughness Rz of 200 nm, a surface distortion Rsk of +0.50, and a surface edge Rku of 3 was obtained in the same manner as in Example 10 except that the friction treatment was not performed. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 10.

(Comparative Example 6)
The amount of work energy (KJ) was changed as shown in Table 4, except that the friction processing material with a surface fabric made of PET was used instead of the friction processing material with a surface fabric made of cotton. In the same manner as in Example 10, a release film having a surface roughness Rz of 258 nm, a surface distortion Rsk of −0.34, and a surface edge Rku of 3 was obtained. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 10.

(Comparative Example 7)
The amount of work energy (KJ) was changed as shown in Table 4, except that the friction processing material with a surface fabric made of PET was used instead of the friction processing material with a surface fabric made of cotton. In the same manner as in Example 10, a release film having a surface roughness Rz of 280 nm, a surface distortion Rsk of +0.29, and a surface sharpness Rku of 3 was obtained. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 10.

(Comparative Example 8)
The amount of work energy (KJ) was changed as shown in Table 4, except that it was friction-treated with a friction treatment material with a woven fabric made of wool as a surface material instead of a friction treatment material with a woven fabric made of cotton as a surface material. In the same manner as in Example 10, a release film having a surface roughness Rz of 240 nm, a surface distortion Rsk of +0.25, and a surface sharpness Rku of 4 was obtained. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 10.

(Comparative Example 9)
The amount of work energy (KJ) was changed as shown in Table 4, except that it was friction-treated with a friction treatment material with a woven fabric made of wool as a surface material instead of a friction treatment material with a woven fabric made of cotton as a surface material. In the same manner as in Example 10, a release film having a surface roughness Rz of 460 nm, a surface distortion Rsk of +1.15, and a surface sharpness Rku of 12 was obtained. Further, the crystallinity (%) of the surface layer was calculated in the same manner as in Example 10.

(Evaluation)
The following evaluation was performed about the release film obtained by the Example and the comparative example. The results are shown in Tables 1 to 4.

(1) Releasability (peeling force)
Overlay the epoxy adhesive surface of the coverlay film (CISV-2535, manufactured by Nikkan Kogyo Co., Ltd.) cut into 200 mm square and the surface layer of the obtained release film, and slide vacuum heater press (MKP-3000v-MH- ST, manufactured by Mikado Technos Co., Ltd.) was pressed at a pressure of 30 kgf and 180 ° C. for 6 minutes, and then cured at 23 ° C. and 50% RH for 1 day. Thereafter, an evaluation sample having a width of 30 mm and a length of 150 mm was cut out from the sample after curing, and this evaluation sample was peeled at a peeling speed of 500 mm / min and a peeling angle of 180 ° using Tensilon (STA-1150, manufactured by A & D). The peel force (N / 30 mm) was measured.

(2) Follow-up (embeddability)
Copper-clad laminate (20 cm × 20 cm, polyimide thickness 25 μm, copper foil 18 μm, hereinafter referred to as “CCL”), coverlay film (20 cm × 20 cm, polyimide thickness 12 μm, epoxy resin adhesive layer 15 μm), and obtained The release films were stacked in this order from the bottom, and pressed under the conditions of 160 ° C., 30 kg / cm ² , 30 minutes using a vacuum press to prepare an FPC evaluation sample composed of CCL and a coverlay film. Note that a pattern (200 μm pitch, 100 μm pitch) for evaluating the adhesive flow-out amount was prepared in advance on the coverlay film.
Thereafter, the FPC evaluation sample and the release film were taken out, and the length of the adhesive flowed out was measured by observing the adhesive flow-out amount evaluation hole on the coverlay film with a microscope. The case where the length of the flowed-out adhesive was less than 10 μm, ◯, the case where it was 10 μm or more and less than 20 μm, the case where it was 20 μm or more and less than 30 μm, Δ, and the case where it was 30 μm or more × As evaluated.

1

Release processing layer

2, 2 ', 2 "Other area in surface layer

Claims

A release film having a surface layer,
A release film, wherein a release treatment layer is observed only in a region from the surface of the surface layer to a thickness of 50 to 300 nm.
A release film having a surface layer containing a polyester resin,
In the region from the surface of the surface layer to a thickness of 1 μm, the release film is characterized in that the proportion of carbonyl groups oriented parallel to the surface of the carbonyl groups contained in the polyester resin is 45% or more .
A release film having a surface layer,
The release film is characterized in that the surface layer has a surface roughness Rz of 250 to 450 nm, a surface distortion Rsk of +0.3 to +1.1, and a surface edge Rku of 5 to 11.
The release layer according to claim 1 or 3, wherein the surface layer contains a polyester resin.
The mold release film according to claim 1, 2, 3, or 4, wherein the surface layer has a crystallinity of 25% or less.
When a printed wiring board, a flexible printed board or a multilayer printed wiring board is manufactured by hot press molding a copper-clad laminate or copper foil on a board through a prepreg or a heat-resistant film, and the obtained printed wiring 6. The release film according to claim 1, wherein the release film is used for preventing adhesion to a substrate, a flexible printed circuit board or a multilayer printed wiring board.
When a cover lay film is bonded to a substrate on which a copper circuit is formed by hot press molding via a thermosetting adhesive, and a flexible printed circuit board is manufactured, the bonding between the hot press plate and the cover lay film, or The release film according to claim 1, 2, 3, 4 or 5, which is used for preventing adhesion between the coverlay films.
6. The release film according to claim 1, wherein the mold release film is used for preventing adhesion between a molding die and a molding resin when a semiconductor mold is manufactured by hot press molding.