JP2017205902A - Release film suitable for manufacture of multilayer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a release film for process which can be easily and sufficiently peeled from a metal surface having high degree of roughness such as blacking-treated copper foil even after a process on a severe condition such as hot press on such a condition that a temperature, a pressure and the like are higher than a conventional one or hot press for a longer time.SOLUTION: A releaser film for process contains a thermoplastic resin, where at least one surface thereof has the following characteristics: (1) a film restorability value R measured by a nanoindentation method at a test temperature of 180°C is R≥70(%).SELECTED DRAWING: None

Description

  The present invention relates to a release film for a process excellent in releasability from a metal surface having a high surface roughness such as so-called blackened copper foil, more specifically, a roughened copper foil layer. The present invention relates to a process release film suitably used for the production of a metal / resin laminate such as a multilayer printed wiring board, and a method for producing a metal / resin laminate such as a multilayer printed wiring board using the same.

In recent years, with the rapid progress of electronic devices, as the degree of integration of ICs increases, printed wiring boards are frequently used for the purpose of meeting demands for higher accuracy, higher density, and higher reliability.
As this printed wiring board, there are a single-sided printed wiring board, a double-sided printed wiring board, a multilayer printed wiring board, and a flexible printed wiring board. Among them, a multilayer printed board (hereinafter also referred to as “MLB”) is that an insulating layer is integrated in the middle of three or more conductors so that any conductors and electronic components to be mounted can be connected to any conductor layer. ) Is expanding.
This MLB has, for example, a pair of single-sided copper-clad laminates or a pair of double-sided copper-clad laminates with double-sided exteriors, and one or two or more inner-layer circuit boards intervening with prepregs (epoxy resin, etc.) interposed therebetween. Stack them, pinch them with a jig and heat press them with a hot platen with a cushioning material to cure the prepreg to form a tightly integrated laminate, drill holes, through hole plating, etc. After that, the surface is etched.
In the process of manufacturing such MLB, a release film is usually used between a copper clad laminate (exterior plate) and a jig. The release film for this process is a high heat-resistant resin that does not melt in the heating and pressurizing step during hot pressing, such as 4-methyl-1-pentene copolymer, polytetrafluoroethylene, polyester, syndiotactic polystyrene. A film having a high rigidity and surface smoothness is used (see, for example, Patent Document 1 to Patent Document 4).

  The copper foil of the copper-clad laminate has a roughened surface like a so-called blackened copper foil that has been roughened by oxidizing the surface to improve adhesion to the epoxy resin or by etching with acid. Treated copper foil is often used. In this case, in the release film for each process described above, there may be a problem that the copper foil surface bites into the film surface in the heating and pressurizing step at the time of hot pressing, and the release film cannot be peeled off.

  On the other hand, a polypropylene and / or polyethylene layer (B) comprising at least one outermost layer of the layer (A) comprising a 4-methyl-1-pentene (co) polymer and substantially free of wax or silicone. A film obtained by uniaxially stretching a sheet provided with 4.3 times or more and then peeling off and removing at least one outermost polypropylene and / or polyethylene layer (B) of the sheet, wherein the film shrinks in the stretching direction. It has been proposed to use a stretched film having a rate of 20% or more (for example, see Patent Document 5).

  However, with the development of this technical field, the level of demand for process release films such as release films for multilayer printed wiring boards is increasing year by year, and even under severe process conditions such as hot presses at higher temperatures and higher pressures. There is a strong demand for a release film for a process that can be easily and sufficiently peeled from a metal surface having a high degree. Simply increasing the rigidity and surface smoothness of the release film has not always been able to meet such requirements.

JP 2004-082717 A Japanese Patent Laid-Open No. 10-67027 JP 2014-8720 A JP 2001-246635 A Japanese Patent No. 4,489,699

  The present invention has been made in view of the above circumstances, even after a process under severe conditions such as a hot press under conditions where the temperature, pressure, etc. are higher than before, or a hot press for a longer time, etc. It is an object of the present invention to provide a release film for a process that can be easily and sufficiently peeled from a metal surface having a high roughness such as a blackened copper foil.

As a result of intensive studies to solve the above problems, the present inventors have focused on the film resilience value R measured by the nanoindentation method at a test temperature of 180 ° C., and the film resilience value R is a constant value. When it was above, it discovered that the said subject was solved effectively and came to complete this invention.
That is, the present invention and each aspect thereof are as described in [1] to [10] below.

[1]
Process release film comprising a thermoplastic resin, the process release film having at least one surface having the following characteristics:
(1) The film resilience value R measured by the nanoindentation method at a test temperature of 180 ° C.
R ≧ 70 (%)
It is.
[2]
Process release film comprising a thermoplastic resin, wherein at least one surface has the following characteristics: Process release film according to [1]:
(2) Hardness H measured by the nanoindentation method at a test temperature of 180 ° C.
H ≧ 40 (MPa)
It is.
[3]
The release film for process according to [2], wherein at least one surface having the characteristic (1) and at least one surface having the characteristic (2) are the same surface.
[4]
The release film for a process according to any one of [1] to [3], comprising a polyester resin and / or a polyamide resin.
[5]
The release film for process according to any one of [1] to [4], which has a stretched or unstretched polyester film layer or a stretched or unstretched polyamide film layer.
[6]
The release film for process according to any one of [1] to [5], which is used for peeling from a roughened metal surface.
[7]
The release film for process according to any one of [1] to [5], which is used for peeling from a metal surface having a surface roughness Ra of 1.0 to 6.5 μm.
[8]
The release film according to any one of [1] to [7] is brought into contact with a roughened metal foil layer on at least one surface having the characteristics of (1) above and subjected to hot press And a step of peeling the process release film from the metal foil layer,
A method for producing a metal / resin laminate, comprising:
[9] The manufacturing method according to [8], wherein the metal / resin laminate is a multilayer printed wiring board.
[10]
An electrical and electronic apparatus having a multilayer printed circuit board manufactured by the manufacturing method according to [9].

The release film for a process of the present invention is a blackened copper foil or the like even after a process under severe conditions such as a heat press under conditions where temperature, pressure, etc. are higher than before, or a hot press for a longer time. It can be easily and sufficiently peeled from a metal surface having a high roughness without using a release agent or the like, and without using a high-melting engineering plastic that is expensive and difficult to process. That is, it realizes a technical effect having a high value in practical use, which could not be realized by the prior art.
The manufacturing method using the release film for a process of the present invention can manufacture an electrical / electronic component having a metal / resin laminated structure such as a multilayer printed wiring board with high flexibility and high productivity.

It is a schematic sectional drawing of the hardened double-sided copper clad laminated board which the copper foil layer laminated | stacked on both surfaces of the glass fiber-epoxy resin composite insulator. It is the schematic sectional drawing which showed the state which laminated | stacked the adhesive prepreg and the copper foil layer on the double-sided copper clad laminated board of FIG. 1, and laminated | stacked the release film on both surfaces. It is a schematic sectional drawing of the multilayer laminated board obtained by pressure-molding the multilayer laminated board of FIG. It is the schematic sectional drawing which showed the state which laminated | stacked the adhesive prepreg and the double-sided copper clad laminated board on the multilayer laminated board of FIG. 3, and laminated | stacked the release film on both surfaces. It is a schematic sectional drawing of the multilayer laminated board obtained by pressure-molding the multilayer laminated board of FIG.

(Release film for process)
The release film for a process of the present invention is a film comprising a thermoplastic resin, and at least one surface thereof is a film resilience value measured by a nanoindentation method with a maximum indentation load of 2 mN at a test temperature of 180 ° C. It has the characteristic (characteristic (1)) that R is 70 (%) or more.
When the film restorability value R is in the above range, peeling from a highly rough metal surface such as a blackened copper foil, especially a relatively high temperature, high pressure, and / or a long rough metal surface, Peeling after adhesion becomes easy. Therefore, the process release film of the present invention is a production of a metal / resin laminate having a metal layer having a surface with high roughness, particularly a multilayer printed wiring having a copper foil layer subjected to blackening treatment and roughening treatment. It can use especially suitably for manufacture of a board.
The film resilience value R is determined by unloading a triangular pyramid diamond indenter (Berkovich indenter) with a maximum indentation load of 2 mN into a film measurement surface using a nanoindenter at a measurement temperature of 180 ° C. From the ratio of the indentation depth at the time of the maximum indentation load (2 mN) and the indentation depth after unloading (0 mN), it is calculated according to the following formula.
Film restorability value R (%) = (indentation depth after unloading / indentation depth at maximum indentation load) × 100

The mechanism that the peeling from the metal surface with high roughness such as the blackened copper foil surface is facilitated by the film restoring value R being in the above range is not always clear, and is restricted by a specific theory. It is not intended to follow the uneven pattern on the metal surface with high roughness when it is hot pressed in close contact with the metal surface with high roughness at a relatively high temperature, high pressure and / or for a long time. It is presumed that the film surface deformed in this way has some relationship with the fact that the adhesion with the metal surface is partially eliminated by restoring to a smoother shape.
The film restorability value R is more preferably 73% or more, and particularly preferably 75% or more.
From the viewpoint of releasability, the film restorability value R is preferably higher. In the present invention, there is no particular upper limit, but from the viewpoint of processability, handling, etc., it is preferably 90% or less, and 85% or less. Particularly preferred.
The type of the resin used for setting the film restorability value R of the release film of the present invention in the above range is not particularly limited, and is a polytetrahedral resin including a polyester resin, a polyamide resin, and a structural unit derived from tetrafluoroethylene. It can be used by appropriately selecting from fluororesin such as fluoroethylene and ethylene-tetrafluoroethylene copolymer, urethane resin, polystyrene resin and the like. Moreover, these can also be used together.
The resin used may be a thermoplastic resin, or a thermosetting resin or an active energy ray curable resin that crosslinks by applying active energy rays such as ultraviolet rays and electron beams.
In order to make the film restorability value R of the release film of the present invention within the above range, a method of increasing the molecular weight of the resin, a method of adding a crosslinking agent containing a reactive group such as an epoxy group to the resin film, and stretching orientation It can be suitably adjusted by a method of aligning resin molecules, a method of heat-treating a resin film, or the like. The release film of the present invention includes, for example, a rubbing treatment for the film surface as another method for achieving the film restoring value R. When the surface hardness is to be achieved by performing a rubbing treatment on the surface of the release film, the rubbing method is not particularly limited, and for example, a known rubbing apparatus can be used.

In the process release film of the present invention, at least one surface has a characteristic that the hardness H measured by the nanoindentation method with a maximum indentation load of 2 mN at a test temperature of 180 ° C. is 40 (MPa) or more. It is preferable to have (2)).
Due to the hardness H being in the above range, peeling from a rough metal surface such as a roughened copper foil surface, in particular, adhesion to a high roughness metal surface at a relatively high temperature, high pressure, and / or long time. Later peeling becomes easier. Accordingly, the process release film of the present invention, which has the above-mentioned characteristic (2), is a method for producing a multilayer printed wiring board having a metal surface having a high roughness such as a blackened copper foil layer. Furthermore, it can be used more suitably.
Hardness H was measured when a triangular pyramid diamond indenter (Berkovich indenter) with a ridge angle of 115 ° was pushed into the film measurement surface with a maximum pushing load of 2 mN using a nanoindenter at a measurement temperature of 180 ° C. The maximum indentation load (F _max ) and the indentation depth (h _c ) are calculated according to the following formula.
Hardness H = F _max /(23.96×h _c ² )

The mechanism by which the hardness H is within the above range makes it easier to separate from a roughened metal surface, such as a blackened copper foil surface, is not always clear, and is bound by a specific theory. Although it is not intended to have a high hardness, the surface of the film having a high hardness has a high degree of roughness even when it is hot-pressed in close contact with a metal surface having a high roughness at a relatively high temperature, high pressure and / or for a long time. It is estimated that the degree of deformation following the uneven pattern on the high metal surface is small, and that there is some relationship with the low degree of adhesion to the metal surface.
The hardness H is more preferably 45 MPa or more, and particularly preferably 55 MPa or more.
From the viewpoint of releasability, the film preferably has a higher hardness H. In the present invention, there is no particular upper limit, but from the viewpoint of workability, handling, etc., it is preferably 130 MPa or less, and particularly preferably 115 MPa or less.

  In order to set the hardness H of the release film of the present invention in the above range, a method of increasing the molecular weight of the resin, a method of adding a cross-linking agent containing a reactive group such as an epoxy group to the resin film, a resin molecule by stretching orientation It can adjust suitably by the method of aligning orientation, the method of heat-processing a resin film, etc.

In the said aspect of the release film for processes of this invention, it is that at least 1 surface which has the characteristic of said (1) and at least 1 surface which has the characteristic of said (2) are the same surfaces. preferable. That is, in the above aspect of the present invention, it is preferable that at least one surface has the above-mentioned characteristic (1) and the characteristic (2) at the same time.
Since the at least one surface has the characteristics (1) and (2) at the same time, peeling from a metal surface having a high roughness is further facilitated. In particular, it is particularly suitable for use in contact with a metal surface having a high surface roughness such as a so-called blackened copper foil.

In the process release film of the present invention, the contact angle with respect to water of at least one surface thereof, preferably at least one surface having the above property (1), is preferably 90 ° to 130 °. By having such a contact angle, the release film for process of this embodiment has low wettability, excellent peelability from a highly rough metal surface, particularly a blackened copper foil surface, and a multilayer printed wiring board. It is possible to further facilitate the release of the molded product such as after the hot pressing.
The contact angle of at least one surface with respect to water is preferably 95 ° to 120 °, more preferably 98 ° to 115 °, and still more preferably 100 ° to 110 °.

Further, the release film for a process of the present invention preferably has a tensile elastic modulus at 120 ° C. of 75 MPa to 500 MPa, or a tensile elastic modulus at 170 ° C. of 75 MPa to 500 MPa. Further, the process release film of the present invention preferably has a tensile elastic modulus at 120 ° C. of 75 MPa to 500 MPa and a tensile elastic modulus at 170 ° C. of 75 MPa to 500 MPa.
When the tensile elastic modulus at 120 ° C. is from 75 MPa to 500 MPa, or the tensile elastic modulus at 170 ° C. is from 75 MPa to 500 MPa, generation of wrinkles in a hot press process or the like can be effectively suppressed.

The release film for a process of this embodiment preferably has a tensile modulus at 120 ° C. of 80 MPa to 400 MPa, more preferably 85 MPa to 350 MPa, further preferably 88 MPa to 300 MPa, 90 MPa To 280 MPa is particularly preferred.
The process release film of the present embodiment preferably has a tensile modulus at 170 ° C. of 80 MPa to 400 MPa, more preferably 85 MPa to 350 MPa, more preferably 88 MPa to 300 MPa, and 90 MPa. To 280 MPa, more preferably from 95 MPa to 200 MPa, and particularly preferably from 105 MPa to 170 MPa.
Since the release film for process of this embodiment has both the tensile elastic modulus at 120 ° C. and the tensile elastic modulus at 170 ° C. within the above-mentioned preferable range, the degree of freedom and application during processing are expanded. Particularly preferred.

Moreover, the mold release film for a process of the present invention has a thermal dimensional change rate from 23 ° C. to 120 ° C. in the TD direction (lateral direction) of 3% or less, or 23 in the TD direction (lateral direction). It is preferable that the thermal dimensional change rate from 0 ° C. to 170 ° C. is 4% or less. Furthermore, the thermal dimensional change rate from 23 ° C. to 120 ° C. in the TD direction (lateral direction) is 3% or less, and the thermal dimensional change rate from 23 ° C. to 170 ° C. in the TD direction (lateral direction) is 4% or less. It is more preferable that
The thermal dimensional change rate from 23 ° C. to 120 ° C. in the TD direction (lateral direction) is 3% or less, or the thermal dimensional change rate from 23 ° C. to 170 ° C. in the TD direction (lateral direction) is 4%. By being below, the generation | occurrence | production of soot in a hot press process etc. can be suppressed still more effectively. In this embodiment, the mechanism by which the rate of thermal dimensional change in the transverse (TD) direction exhibits the specific value described above is used to suppress the generation of wrinkles more effectively. It is presumed that the use of a film having a small shrinkage / shrinkage is related to the suppression of the thermal expansion / shrinkage of the process release film due to heating / cooling during the process.

The mold release film for a process according to this embodiment preferably has a thermal dimensional change rate from 23 ° C. to 120 ° C. in the TD direction (lateral direction) of 2.5% or less, and is 2.0% or less. More preferably, it is still more preferably 1.5% or less. On the other hand, the thermal dimensional change rate from 23 ° C. to 120 ° C. in the TD direction (lateral direction) is preferably −5.0% or more.
The mold release film for a process of the present embodiment preferably has a thermal dimensional change rate from 23 ° C. to 170 ° C. in the TD direction (lateral direction) of 3.5% or less, and is 3.0% or less. Is more preferable, and it is still more preferable that it is 2.0% or less. On the other hand, the thermal dimensional change rate from 23 ° C. to 170 ° C. in the TD direction (lateral direction) is preferably −5.0% or more.

The release film for process of the present invention is the sum of the thermal dimensional change rate in the TD direction (transverse direction) and the thermal dimensional change rate in the MD direction (longitudinal direction at the time of manufacturing the film; hereinafter also referred to as “longitudinal direction”). Is preferably not more than a specific value.
That is, the sum of the thermal dimensional change rate from 23 ° C. to 120 ° C. in the transverse (TD) direction and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the longitudinal (MD) direction of the release film for process is 6%. On the other hand, the sum of the thermal dimensional change rate from 23 ° C. to 120 ° C. in the TD direction (lateral direction) and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the vertical (MD) direction is − It is preferably 5.0% or more.
In the release film for process of this embodiment, the sum of the thermal dimensional change rate from 23 ° C. to 120 ° C. in the transverse (TD) direction and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the vertical (MD) direction is 6. % Or less, generation of wrinkles in a hot press process or the like can be further effectively suppressed.

Moreover, the sum of the thermal dimensional change rate from 23 ° C. to 170 ° C. in the transverse (TD) direction and the thermal dimensional change rate from 23 ° C. to 170 ° C. in the longitudinal (MD) direction of the release film for process of the present invention is: It is preferably 7% or less. On the other hand, the sum of the thermal dimensional change rate from 23 ° C. to 170 ° C. in the TD direction (lateral direction) and the thermal dimensional change rate from 23 ° C. to 170 ° C. in the vertical (MD) direction. Is preferably −5.0% or more.
In the release film for process of this embodiment, the sum of the thermal dimensional change rate from 23 ° C. to 170 ° C. in the transverse (TD) direction and the thermal dimensional change rate from 23 ° C. to 170 ° C. in the vertical (MD) direction is 7 % Or less makes it possible to more effectively suppress the generation of wrinkles in a hot press process or the like.

  The thickness of the release film for a process of the present invention is not particularly limited as long as it can be formed as a film and can be used as a release film, but is usually 5 to 150 μm, preferably 15 to 15 μm. The thickness is 100 μm, more preferably 25 to 80 μm.

  The at least one surface of the release film for a process of the present invention satisfies the characteristic (1) that the film restoration value R measured by the nanoindentation method at a test temperature of 180 ° C. is R ≧ 70 (%). There is no particular limitation on the material and the like, but it is desirable to include a polyester resin and / or a polyamide resin because an appropriate film restoring value R can be realized relatively easily and inexpensively.

(Polyester resin)
The polyester resin preferably used in the present invention may be a homopolyester or a copolyester. When using a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Typical polyesters include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and the like. On the other hand, examples of the dicarboxylic acid component used in the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, P-oxybenzoic acid, etc.), etc. As the glycol component, one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like can be mentioned.

The polyester preferably used in the present invention may be obtained by a melt polymerization reaction, but is included in the raw material if a raw material obtained by solid-phase polymerization of a polyester formed into a chip after melt polymerization is used. This is particularly preferable because the amount of oligomer can be reduced.
The amount of oligomer contained in the polyester is preferably 0.7% by weight or less, and more preferably 0.5% by weight or less. When the amount of the oligomer of the polyester is small, the amount of the oligomer contained in the process release film of the present invention is reduced, and further, the effect of preventing oligomer precipitation on the film surface is exhibited to a high degree.

In the aspect in which the release film for process contains a polyester resin, particles can be blended in the layer containing the polyester resin for the main purpose of imparting slipperiness. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples of the particles include magnesium, kaolin, aluminum oxide, and titanium oxide. Further, the heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, during the polyester production process, it is possible to use precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed. On the other hand, the shape of the particles to be used is not particularly limited. Either a rod shape or a flat shape may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.
Moreover, the average particle diameter of the particle | grains to be used is 0.01-3 micrometers normally, Preferably it is the range of 0.01-1 micrometer. If the average particle diameter is 0.01 μm or more, aggregation of the particles is suppressed and sufficient dispersibility can be easily realized, while if it is 3 μm or less, the surface roughness of the film is within a practically preferable fixed limit. To be suppressed.

Furthermore, the particle content in the polyester layer is usually in the range of 0.001 to 5% by weight, preferably 0.005 to 3% by weight. If the particle content is 0.001% by weight or more, the slipperiness of the film is sufficient, while if it is 5% by weight or less, sufficient transparency of the film is ensured.
The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage of producing the polyester constituting each layer, but preferably a polycondensation reaction may be carried out after the esterification stage or after the transesterification reaction.
Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a blending of dried particles and a polyester raw material using a kneading extruder. You may carry out by the method etc.

(Polyamide resin)
The polyamide resin preferably used in the present invention may be an aliphatic polyamide resin or an aromatic polyamide resin, but an aliphatic polyamide resin is more preferable.
The aliphatic polyamide resin can be produced by ring-opening polymerization of lactam; polycondensation reaction between an aliphatic diamine component and an aliphatic dicarboxylic acid component; polycondensation of an aliphatic aminocarboxylic acid, or the like.

  Examples of the aliphatic polyamide obtained by ring-opening polymerization of lactam include polyamide 6, polyamide 11, polyamide 12 and polyamide 612. Examples of the aliphatic polyamide obtained by polycondensation of an aliphatic diamine component and an aliphatic dicarboxylic acid component include polyamide 66, polyamide 610, polyamide 46, polyamide MXD6, polyamide 6T, polyamide 6I, and polyamide 9T.

Of these, polyamide 6 or polyamide 66 is preferred; polyamide 66 is more preferred. This is because these polyamides can realize the above-mentioned property (1) relatively easily, have a high melting point and a high elastic modulus, and are excellent in heat resistance and mechanical properties. Moreover, since adhesiveness with another layer is comparatively favorable, it is advantageous also when comprising a laminated film.
Films made of polyamide with a high melting point and high elastic modulus, and excellent heat resistance and mechanical properties are suitable from the viewpoint of keeping molded products and press devices clean because wrinkles, tears, etc. are effectively suppressed. is there.
The melting point of aliphatic polyamide measured by DSC method is preferably 190 ° C. or higher. By having a melting point of 190 ° C. or higher, soot can be effectively suppressed even when subjected to a process such as hot pressing at a relatively high temperature.

(Other resins)
The above-described polyester resin or polyamide resin may further include other resins other than the polyester resin or the polyamide resin. Preferred examples of other resins include heat-resistant elastomers that are excellent in creep resistance against tensile stress and compressive stress at high temperatures, and heat-resistant elastomers that are less susceptible to stress relaxation and have high elastic recovery properties.
As such a heat-resistant elastomer, in view of the affinity with a polyester resin or a polyamide resin, a thermoplastic polyamide-based elastomer, a thermoplastic polyester-based elastomer, or the like is preferable.
Examples of the thermoplastic polyamide-based elastomer include a block copolymer having polyamide as a hard segment and polyester or polyether as a soft segment. Examples of the polyamide constituting the hard segment include polyamide 6, polyamide 66, polyamide 610, polyamide 612, polyamide 11 and the like. Examples of the polyether constituting the soft segment include polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG), and the like.

  Examples of thermoplastic polyester elastomers include block copolymers in which a crystalline polymer composed of crystalline aromatic polyester units is used as a hard segment, and an amorphous polymer composed of polyether units or aliphatic polyester units is used as a soft segment. A polymer is included. Examples of the crystalline polymer comprising crystalline aromatic polyester units constituting the hard segment include polybutylene terephthalate (PBT) and polybutylene naphthalate (PBN). Examples of the amorphous polymer composed of polyether units constituting the soft segment include polytetramethylene ether glycol (PTMG). Examples of the amorphous polymer composed of aliphatic polyester units constituting the soft segment include aliphatic polyesters such as polycaprolactone (PCL).

  Specific examples of the thermoplastic polyester elastomer include a block copolymer of polybutylene terephthalate (PBT) and polytetramethylene ether glycol (PTMG); a block copolymer of polybutylene terephthalate (PBT) and polycaprolactone (PCL). Polymers; block copolymers of polybutylene naphthalate (PBN) and aliphatic polyesters are included.

  The melting point of the thermoplastic polyamide-based elastomer and the thermoplastic polyester-based elastomer measured by the DSC method is preferably 190 ° C. or higher. Even if the melting point of the thermoplastic elastomer is less than 190 ° C., the thermoplastic elastomer is chemically crosslinked with a crosslinking agent or a crosslinking aid, or physically crosslinked with ultraviolet rays, electron beams, gamma rays, or the like. Thus, creep resistance and elastic recovery at high temperatures may be improved.

  The said polyester resin or polyamide resin may further contain the well-known additive in the range which does not impair the objective of this invention. Additives are known additives such as antistatic agents, antioxidants, heat stabilizers including, for example, copper compound systems, lubricants such as calcium stearate and aluminum stearate, thermal stabilizers, lubricants, dyes, pigments, etc. Any of these agents or a combination thereof may be used.

(Polyester film layer and polyamide film layer)
The polyester resin or polyamide resin preferably used in the present invention is usually used in the form of a stretched or unstretched film. That is, the process release film of the present invention preferably has a stretched or unstretched polyester film layer or a stretched or unstretched polyamide film layer.

  The thickness of the polyester film layer suitable for constituting all or part of the release film for a process of the present invention is not particularly limited as long as it can be formed as a film. It is 250 μm, preferably 25 to 188 μm, more preferably 38 to 125 μm. When it is a stretched polyester film, it is preferably 3 to 50 μm, preferably 5 to 35 μm, and more preferably 7 to 20 μm. Moreover, when it is an unstretched polyester film, it is preferable that it is 5-80 micrometers, It is more preferable that it is 8-50 micrometers, It is especially preferable that it is 10-35 micrometers.

There is no restriction | limiting in particular in the manufacturing method of the said polyester film, Although it can manufacture suitably by a conventionally well-known method, when it is a stretched polyester film, it is preferable to manufacture according to the guideline described below, for example.
First, a method of using the polyester resin described above and cooling and solidifying a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet is preferable. In this case, in order to improve the flatness of the sheet, it is necessary to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed. Next, the obtained unstretched sheet is preferably stretched in the biaxial direction. In the case of sequential biaxial stretching, the unstretched sheet is first stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Subsequently, it can extend | stretch in the direction orthogonal to the extending | stretching direction of the 1st step | paragraph. The stretching temperature is usually 70 to 170 ° C., and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% to obtain a biaxially oriented film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  In addition, the simultaneous biaxial stretching method can be adopted for the production of the polyester film in this embodiment. The simultaneous biaxial stretching method is a method in which the unstretched sheet is usually stretched and oriented in the machine direction and the width direction at 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is as follows: The area magnification is generally 4 to 50 times, preferably 7 to 35 times, more preferably 10 to 25 times. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a stretched oriented film. Regarding the simultaneous biaxial stretching apparatus that employs the above-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, a linear drive method, and the like can be appropriately employed.

  Furthermore, when the above-mentioned polyester film layer has the coating layer provided in the surface, what is called the coating extending | stretching method (in-line coating) which processes a film surface during the extending | stretching process of the above-mentioned polyester film can be given. When a coating layer is provided on a polyester film by a coating stretching method, the coating film can be applied simultaneously with stretching and the thickness of the coating layer can be reduced according to the stretching ratio, and a polyester film having a desired coating layer The layer can be manufactured efficiently.

  The thickness of the polyamide film suitable for constituting all or part of the release film for process of the present invention is not particularly limited as long as it can be formed as a film, but is usually 12 to 250 μm. , Preferably 25 to 188 μm, more preferably 38 to 125 μm. When it is a stretched polyamide film, it is preferably 3 to 50 μm, preferably 5 to 35 μm, and more preferably 7 to 20 μm. Moreover, when it is an unstretched polyamide film, it is preferable that it is 5-80 micrometers, It is more preferable that it is 8-50 micrometers, It is especially preferable that it is 10-35 micrometers.

There is no restriction | limiting in particular in the manufacturing method of the said polyamide film, Although it can manufacture suitably by a conventionally well-known method, when it is a stretched polyamide film, it is preferable to manufacture according to the following description, for example.
The stretched polyamide film can be obtained by, for example, extruding a polyamide resin to form a film (raw film) and then stretching. When extruding a polyamide resin, the polyamide resin may be extruded alone, or may be used by dry blending a polyamide resin and another resin, for example, a thermoplastic polyamide-based elastomer. Or what was melt-kneaded using the twin-screw extruder can also be used.
When producing a biaxially stretched polyamide film, it is preferable to stretch the resulting unstretched film in the biaxial direction. In the case of sequential biaxial stretching, the unstretched sheet is first stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 30 to 220 ° C., preferably 50 to 210 ° C., and the stretching ratio is usually 1.5 to 4.5 times, preferably 2.5 to 4.0 times. Subsequently, it can extend | stretch in the direction orthogonal to the extending | stretching direction of the 1st step | paragraph. The stretching temperature is usually 30 to 220 ° C., and the stretching ratio is usually 1.5 to 4.5 times, preferably 2.5 to 4.0 times.
And it heat-processes at the temperature of 190-210 degreeC continuously, and obtains a biaxially stretched polyamide film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  For the production of the polyamide film in this embodiment, a simultaneous biaxial stretching method can also be employed. The simultaneous biaxial stretching method is a method in which the unstretched polyamide film is usually stretched and oriented in the machine direction and the width direction at 30 to 220 ° C., preferably 50 to 210 ° C., and the stretching ratio is as follows. The area magnification is generally 1.5 to 20 times, preferably 5 to 15 times, more preferably 8 to 12 times. Subsequently, heat treatment is performed at a temperature of 190 to 210 ° C. to obtain a stretch-oriented polyamide film. Regarding the simultaneous biaxial stretching apparatus that employs the above-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, a linear drive method, and the like can be appropriately employed.

(Multilayer film)
As long as the object of the present invention is not contrary to the object of the present invention, it may be a single layer or a multilayer film having two or more layers.
In the case of a multilayer film of two or more layers, at least one surface of at least one layer located in the outermost layer has (1) a film resilience value R measured by a nanoindentation method at a test temperature of 180 ° C. R ≧ 70 (%).
There is no particular limitation on the material of each film constituting the multilayer film of two or more layers, but the film restoration value R measured by the nanoindentation method at the test temperature of 180 ° C. is R ≧ 70 (% It is preferable that the at least 1 layer which has the characteristic that it is) contains the polyester resin and / or the polyamide resin.

  The layer other than the at least one layer having the characteristic (1) may be a layer containing a polyester resin and / or a polyamide resin, or other resin, for example, other thermoplastic resin. It may be a layer comprising. More specifically, for example, polyphenylene sulfide resin (PPS resin), polysulfone resin (PSF resin), polyether sulfone resin (PES resin), polyether ether ketone resin (PEEK resin), polyimide resin (PI resin), Polyamideimide resin (PAI resin), polyetherimide resin (PEI resin), polyethylene naphthalate resin (PEN resin), polyacetal resin (POM resin), polycarbonate resin (PC resin), polyphenylene ether resin (PPE resin), polybutylene Terephthalate resin (PBT resin), polyethylene terephthalate resin (PET resin), cyclic polyolefin resin (COP resin), syndiotactic polystyrene resin (SPS resin), polymethylpentene resin (PMP resin), Methyl methacrylate resin (PMMA resin), polyethylene resin (PE resin), polypropylene resin (PP resin), polystyrene resin (PS resin), polyvinyl acetate resin (PVAc resin), acrylonitrile butadiene styrene resin (ABS resin) or acrylonitrile styrene resin It may be a layer comprising (AS resin) or a combination thereof.

  In the above embodiment, the method for laminating two or more resin layers is not particularly limited, and a conventionally known method can be appropriately used. For example, a layer containing a polyester resin and / or a polyamide resin, and the like can be used. When laminating a layer made of the above resin, a polyester resin and / or a polyamide resin and another resin may be coextruded to obtain a multilayer film (raw film), which may be stretched. Or you may laminate | stack the stretched film which consists of the polyester resin and / or polyamide resin which were obtained separately, and the stretched film which consists of other resin by thermocompression bonding, an adhesive agent, an adhesive layer, etc. In order to obtain a raw film by coextruding a polyester resin and / or a polyamide resin and another resin, a film forming method such as a normal T die method or a cylindrical die method (inflation method) can be used.

  Adhesive, adhesive when laminating with an adhesive layer, resin used for the adhesive layer is not particularly limited as long as it can improve the adhesive force between the two layers. Adhesives typified by system compounds, acrylic compounds and urethane compounds can be appropriately selected and used. Further, a resin obtained by graft-modifying a polyester resin, a polyamide resin, another resin, or a resin that is the same or similar to a plurality thereof with an unsaturated carboxylic acid and / or an acid anhydride thereof may be used. Good.

Examples of unsaturated carboxylic acids and / or acid anhydrides used as graft monomers include unsaturated compounds having one or more carboxylic acid groups having 3 to 20 carbon atoms and unsaturated compounds having one or more carboxylic anhydride groups. Examples of the unsaturated group include a vinyl group, a vinylene group, and an unsaturated cyclic hydrocarbon group. Specifically, unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid; maleic acid, fumaric acid, itaconic acid, citraconic acid, allyl succinic acid, mesaconic acid, glutaconic acid, nadic acid TM, methyl nadic acid, tetrahydrophthalic acid Unsaturated dicarboxylic acids such as methylhexahydrophthalic acid; maleic anhydride, itaconic anhydride, citraconic anhydride, allyl succinic anhydride, glutaconic anhydride, nadic acid TM, anhydrous methyl nadic acid, tetrahydrophthalic anhydride, methyl anhydride And unsaturated dicarboxylic acid anhydrides such as tetrahydrophthalic acid. These can be used alone or in combination of two or more. Of these, maleic acid, maleic anhydride, nadic acid, and nadic anhydride are preferable.
The graft ratio is usually less than 20% by weight, preferably 0.1 to 5% by weight, more preferably 0.5 to 2% by weight. When the graft amount is in the above range, the graft-modified resin can achieve sufficient adhesion without impairing mechanical properties, stability, and the like as the resin. The graft-modified resin can be produced by a known graft polymerization method such as a solution method or a melt-kneading method. Among them, a solution method obtained in the form of a solution is preferable.

The release film for a process of the present invention is a metal surface such as a copper foil having a high roughness even under severe conditions such as hot pressing under conditions of higher temperature, pressure, etc. Therefore, it is possible to easily and sufficiently peel off a metal surface having a large surface roughness, a process involving peeling from a roughened metal surface, for example, metal / including multilayer printed wiring boards, It can use preferably in the manufacturing process of a resin laminated body.
When the process release film of the present invention is used in a metal / resin laminate manufacturing process, the process release film of the present invention is measured by (1) a nanoindentation method at a test temperature of 180 ° C. And at least one surface having the characteristic that the film restorability value R is R ≧ 70 (%), is hot-pressed in contact with the roughened metal foil layer, and then separated for the process. The mold film is peeled from the metal foil layer.
The surface roughness of a copper foil layer such as a single-sided copper-clad laminate or a double-sided copper-clad laminate used as a material for a multilayer printed wiring board is usually 1.0 to 6.5 μm in Rz, typically 1.5 to 4 The release film for process of the present invention is particularly suitable for peeling from a metal surface such as a copper foil layer having such surface roughness.

  Hereinafter, the use of the process release film of the present invention in the production of a multilayer printed wiring board will be described by taking the production of a five-layer printed wiring board as an example.

  After forming a printed wiring pattern on the copper foil layer 2 and the copper foil layer 3 of the double-sided copper-clad laminate composed of the copper foil layer 2, the copper foil layer 3, and the cured glass fiber-epoxy resin composite insulator 1, the copper foil layer 2. A blackening treatment or an etching treatment using an organic acid-based etching treatment agent is performed on the copper foil layer 3. The etching process such as the blackening process is a process of roughening the surface of the copper foil, and can improve the adhesion to the adhesive prepreg.

Next, the first multilayer lamination is performed between the substrate and the copper foil layer 7 using the adhesive prepreg 6. At this time, the process release film 4 corresponding to the present invention is placed outside the copper foil layer 2, and the process release film 5 also corresponding to the present invention is placed outside the copper foil layer 7, and laminated. Heating and pressing are performed by hot pressing in a direction perpendicular to the surface (FIG. 2). The conditions for heating and pressurization are preferably, for example, 190 ° C., pressure 30 kg / cm ² , and time 40 minutes.
After heating and pressing, the process release films 4 and 5 of the present invention can be easily peeled off, and the occurrence of scratches on the surfaces of the copper foil layers 2 and 7 can be effectively suppressed (see FIG. 3).

Then, as shown in FIG. 4, the laminated board which consists of the copper foil layer 11, the copper foil layer 9, and the hardened glass fiber-epoxy resin composite insulator 10, and the copper foil layer 2, the copper foil layer 3, copper which were created previously A second multi-layer lamination is performed on the three-layer substrate made of the foil layer 7 using the adhesive prepreg 8. The release film 5 and the release film 4 are placed on the outer sides of the copper foil layer 11 and the copper foil layer 2 and heated and pressurized to perform lamination integration. The heating and pressing conditions are preferably, for example, 190 ° C., pressure 30 kg / cm ² , and time 40 minutes.
After heating and pressing, the process release films 4 and 5 of the present invention can be easily peeled off, and the occurrence of scratches on the surfaces of the copper foil layers 2 and 11 can be effectively suppressed (see FIG. 5).

  In the above, the use of the process release film of the present invention in the manufacture of a multilayer printed wiring board has been described by taking the production of a five-layer printed wiring board as an example, but the process release film of the present invention has other configurations. It can be suitably used in the production of multilayer printed wiring boards. Moreover, not only in multilayer printed wiring boards, but also in manufacturing processes that heat and press members with high roughness metal surfaces, such as in the manufacture of metal / resin laminates, take advantage of the excellent peelability from rough surfaces. And can be preferably used.

  By using the process release film of the present invention, a multilayer printed wiring board can be produced with high quality, low cost, and high production efficiency. Such a multilayer printed wiring board can be suitably used for mounting electronic components, and is suitably mounted on electrical and electronic equipment used for information processing equipment, displays, communication equipment, transportation equipment, and the like.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by this.

In the following examples / comparative examples, physical properties / characteristics were evaluated by the following methods.
(Restorability value R of film by nanoindentation method at 180 ° C)
At a measurement temperature of 180 ° C., a triangular pyramid diamond indenter (Berkovich indenter) with a ridge angle of 115 ° was pushed into the film measurement surface with a maximum indentation load of 2 mN using a nanoindenter, and then unloaded to obtain a maximum indentation load (2 mN). ) And the indentation depth after unloading (0 mN) were measured. The ratio of the indentation depth at the maximum indentation load obtained (2 mN) and the indentation depth after unloading (0 mN), calculated according to the following equation, was defined as a film resilience value R.

Film resilience value R = indentation depth after unloading / indentation depth at maximum indentation load

(Hardness H by nanoindentation at 180 ° C)
At a measurement temperature of 180 ° C., the maximum indentation load when unloading a triangular pyramid diamond indenter (Berkovich indenter) with a ridge angle of 115 ° with a maximum indentation load of 2 mN using a nano indenter and then unloading it. F _max ) and indentation depth (h _c ) were calculated according to the following formula.

Hardness H = F _max /(23.96×h _c ² )

(Releasability)
Process release film is used for the production of copper-clad laminates by hot pressing. After releasing the press and cooling, it is attempted to peel by applying tension to the release film for process by hand, and the peelability is evaluated according to the following criteria. did.
○: When a tension was applied after the press was released, the release film for the process was easily peeled from the surface of the copper foil layer.
X: The mold release film for process has adhered to the copper foil layer surface, and cannot be removed by hand.

[Example 1]
A biaxially stretched PET (polyethylene terephthalate) film (manufactured by Unitika Ltd., product name: emblet PET12) having a film thickness of 12 μm was used as a release film for the process.
The biaxially stretched PET film has a film resilience value R measured by the nanoindentation method at a test temperature of 180 ° C. of 70.8%, and the hardness H measured by the nanoindentation method at the test temperature of 180 ° C. is 111.0 MPa.
The copper clad laminate uses FR4 (both glass epoxy / copper foil 18 μm, 250 × 200 mm × 0.2 mmt), and is an organic acid type etching agent (product name: MEC V Bond BO-7790V). A roughened copper-clad laminate that was etched so that the copper foil surface roughness was Ra: 2 μm was used. The copper-clad laminate and the copper-clad laminate are overlapped via a resin layer (adhesive prepreg), and a process release film is further disposed on the uppermost and lowermost surfaces, and then 180 ° C., 25 kg, 60 minutes. The film was hot-pressed under conditions to confirm the peelability of the film from the copper foil.
When tension was applied by hand after releasing the press and cooling, the release film for the process was easily peeled from the copper foil layer.
[Example 2]
A biaxially stretched nylon film having a film thickness of 15 μm (manufactured by Kojin Film & Chemicals Co., Ltd., product name: Bonil RX) was used as a release film for the process.
The biaxially stretched nylon film had a film resilience value R measured by the nanoindentation method at a test temperature of 180 ° C. of 77.7%, and the hardness H measured by the nanoindentation method at the test temperature of 180 ° C. , 58.7 MPa.
Under the same conditions as in Example 1, the laminate was used in the manufacturing process.
When tension was applied after press release and cooling, the release film was easily peeled from the copper foil layer.
[Example 3]
Commercially available PBT (polybutylene terephthalate) resin (Tm = 224 ° C., IV = 1.2, manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name: NOVADURAN 5020)
) Using a T-die film molding machine of an extruder with a screw diameter of 40 mm, a 20 μm unstretched PBT film is produced under the conditions of a resin temperature of 250 ° C., a chill roll temperature of 80 ° C., and an air chamber static pressure of 440 mm HG, Used as release film for process.
The unstretched PBT film had a film resilience value R measured by the nanoindentation method at a test temperature of 180 ° C. of 78.3%, and the hardness H measured by the nanoindentation method at the test temperature of 180 ° C. It was 68.0 MPa.
Under the same conditions as in Example 1, the laminate was used in the manufacturing process.
When tension was applied after press release and cooling, the release film was easily peeled from the copper foil layer.
[Example 4]
An unstretched nylon film (product name: Reyfan NO1401 manufactured by Toray Film Processing Co., Ltd.) having a film thickness of 20 μm was used as a release film for the process.
The non-stretched nylon film had a film resilience value R measured by the nanoindentation method at a test temperature of 180 ° C. of 76.6%, and the hardness H measured by the nanoindentation method at the test temperature of 180 ° C. It was 81.9 MPa.
Under the same conditions as in Example 1, the laminate was used in the manufacturing process.
When tension was applied after the press was released, the release film was easily peeled from the copper foil layer.
[Comparative Example 1]
A biaxially stretched polyethylene terephthalate (PET) film (manufactured by Toray Film Processing Co., Ltd., product name: Lumirror F865) having a film thickness of 16 μm was used as a release film for the process.
The biaxially stretched PET film had a film resilience value R measured by the nanoindentation method at a test temperature of 180 ° C. of 68.5%, and the hardness H measured by the nanoindentation method at the test temperature of 180 ° C. 34.7 MPa.
Under the same conditions as in Example 1, the laminate was used in the manufacturing process.
Although tension was applied after the press was released, the release film was in close contact with the copper foil layer surface and could not be peeled off by hand.
The results are summarized in Table 1.

  The process release film of the present invention can be easily and sufficiently peeled off from a metal surface having a high roughness even after processing under severe conditions. In the field of electrical and electronic industries including manufacturing of

1: Glass fiber-epoxy resin composite insulator 2: Copper foil layer 3: Copper foil layer 4: Release film 5: Release film 6: Adhesive prepreg 7: Copper foil layer 8: Adhesive prepreg 9: Copper foil layer 10: Glass fiber-epoxy resin composite insulator 11: copper foil layer

Claims (10)

Process release film comprising a thermoplastic resin, the process release film having at least one surface having the following characteristics:
(1) The film resilience value R measured by the nanoindentation method at a test temperature of 180 ° C.
R ≧ 70 (%)
It is. A process release film comprising a thermoplastic resin, wherein at least one surface has the following characteristics:
(2) Hardness H measured by the nanoindentation method at a test temperature of 180 ° C.
H ≧ 40 (MPa)
It is.   The process release film according to claim 2, wherein at least one surface having the characteristic (1) and at least one surface having the characteristic (2) are the same surface.   The mold release film for a process according to any one of claims 1 to 3, comprising a polyester resin and / or a polyamide resin.   The release film for a process according to any one of claims 1 to 4, which has a stretched or unstretched polyester film layer or a stretched or unstretched polyamide film layer.   The release film for a process according to any one of claims 1 to 5, which is used for peeling from a roughened metal surface.   The release film for processes according to any one of claims 1 to 5, which is used for peeling from a metal surface having a surface roughness Rz of 1.0 to 6.5 µm. The process release film according to any one of claims 1 to 7 is brought into contact with a roughened metal foil layer on at least one surface having the characteristics of (1) above and subjected to hot press. And a step of peeling the process release film from the metal foil layer,
A method for producing a metal / resin laminate, comprising:   The manufacturing method according to claim 8, wherein the metal / resin laminate is a multilayer printed wiring board.   An electrical and electronic apparatus having a multilayer printed circuit board manufactured by the manufacturing method according to claim 9.