JP2006021372A - Mold release laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold release laminated film excellent in heat resistance, chemical resistance, hydrolysis resistance and mold releasability, having flexibility and cushioning properties following the stepped parts of the circuit of a circuit board, excellent in press workability, not containing a substance which is bled out of a mold release material to stain the circuit board and optimum to a circuit board manufacturing process using a press. <P>SOLUTION: The mold release laminated film is formed by laminating biaxially stretched films (layers A), which comprises a resin composition based on polyphenylene sulfide, on both sides of a resin composition layer (layer B) with a thermal deformation temperature of 70-150°C and constituted so that the ratio of the thickness of the layers A [thickness of layers A/(thickness of layers A + thickness of layer B)] to the whole thickness of the laminated film becomes 0.05-0.5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

   The present invention relates to a laminated film for mold release using a biaxially stretched polyphenylene sulfide film, and in particular, a mold release for a circuit board manufacturing process that requires heat resistance, chemical resistance, hydrolysis resistance, cushioning properties, and the like. The present invention relates to a release film that is optimal for a film.

   In recent years, with the remarkable development of IT equipment, digital equipment, etc., development of multi-function and high-performance circuit boards has been intense, and rigid multi-layer boards, build-up multi-layer boards, flexible printed boards (hereinafter abbreviated as FPCs). And circuit boards that combine these are widely used. These circuit boards are generally laminated by a hot plate press. For example, in the case of a build-up multilayer substrate, a metal layer of a conductor is laminated on a previously manufactured circuit substrate through an adhesive layer having heat resistance insulation, and the circuit processing is performed in the case of FPC. A circuit board is multilayered or an insulating layer called a coverlay is laminated on the surface layer, and a reinforcing plate is laminated on the back surface of the connector portion of the FPC via an adhesive to improve the strength of the connector portion. In many cases, these are laminated after punching or punching, and a release sheet is inserted between the circuit boards to prevent sticking between the circuit boards due to bleeding of the adhesive. Moreover, it is necessary to laminate | stack so that an insulating layer may fit between the formed circuits, and the followability and the cushioning property are requested | required of a release sheet so that a press pressure may be equally applied to a circuit board. In particular, the circuit density of recent circuit boards has been increasing, and the demand has become increasingly strict. The general hot press temperature is about 160 to 190 ° C, but the softening temperature of the adhesive used for the circuit board and the insulating resin layer is different, and the press processing may be performed at a temperature of 200 ° C or higher. There is a demand for improved performance. The press working time is as long as several tens of minutes to several hours, and resistance to gases (chemical resistance) from the adhesive and insulating resin and resistance to hydrolysis by moisture (hydrolysis resistance) are also required. In addition, it is required from the side of the release material that no substance bleeds out from the viewpoint of preventing contamination of the circuit board.

  Conventionally, polyolefin sheets and films and fluorine films are known in this field. Olefin-based sheets and films are excellent in releasability but low in heat resistance. In addition, since a fluorine-based film is not stiff, workability is poor and cost is high. Also, polymethylpentene sheets and laminates of special olefin sheets (see, for example, Patent Document 1) are used.

  On the other hand, it is known that a biaxially stretched polyphenylene sulfide film (hereinafter sometimes abbreviated as a PPS film) is excellent in heat resistance, chemical resistance and mechanical properties (see, for example, Patent Document 2). In addition, the following is known that PPS films are used for mold release.

 (1) A PPS film is used as it is for mold release of a liquid crystal film or the like (see, for example, Patent Documents 3 and 4).

(2) A release film obtained by applying a silicone resin to a PPS film is used as a carrier sheet (release sheet) for a manufacturing process such as a ceramic sheet or a urethane sheet (see Patent Document 5).
(3) A laminated film of a PPS film and a separate organic polymer film in which the adhesion between each film can be peeled is used as a release material for a ceramic green sheet processing process, and the PPS film is used in the processing process. Use while peeling (see, for example, Patent Document 6).
Plastic Film / Resin Material Handbook 1997/98 (Processing Technology Research Group, issued on December 18, 1997) P305-306 JP-A-56-62121 JP 09-278912 A JP 09-300365 A Japanese Patent Laid-Open No. 04-90774 JP 05-261868 A

However, the above TPX sheet, laminated film thereof, PPS film and processed product thereof have the following problems, and development has been limited in the field of release films for circuit board manufacturing processes. Those using TPX sheets are excellent in releasability, chemical resistance, hydrolysis resistance and cushioning properties, but contain a lot of additives such as plasticizers. It has been pointed out that plasticizers bleed out and contaminate circuit boards,
The heat resistance is poor and its use has been limited in press processing at a high temperature exceeding 200 ° C. such as processing of BT resin. In the future, the demand for improvement in heat resistance will be stricter in circuit boards that are multifunctional and highly functional, and contamination of the circuit will become a major problem.

  The PPS film of (1) and the release PPS film of (2) are excellent in heat resistance, chemical resistance, hydrolysis resistance and releasability, but are inferior in cushioning and formed of a conductor such as copper foil. The insulating layer laminated by pressing without the flexibility of following the step of the insulating layer of the circuit floats at the interface between the circuit and the insulating layer after the circuit board is laminated. This phenomenon causes insulation failure and also causes conduction and discharge between circuits and causes a short circuit.

  The laminated film for release using the PPS film of (3) is designed to be used while being peeled in the processing step, so that the adhesion is weak, and another organic polymer sheet is used as the support layer. Therefore, the entire release laminate film is hard and does not easily soften even when heated, and there is a problem in cushioning properties and followability required for the present invention.

  Therefore, in view of the above problems, the present invention is excellent in heat resistance, chemical resistance, hydrolysis resistance and releasability, and gives flexibility and cushioning to follow the steps of the circuit on the circuit board, and press It is intended to provide a release film that is excellent in workability and is optimal for a circuit board manufacturing process using a press.

  The present invention employs the following means in order to solve such problems. That is, a laminated film in which a biaxially stretched film (A layer) made of a resin composition containing polyphenylene sulfide as a main component is laminated on both surfaces of a resin composition layer (B layer) having a heat deformation temperature of 70 to 150 ° C. The ratio of the thickness of the A layer to the total thickness of the laminated film (A layer thickness / (A layer thickness + B layer thickness)) is in the range of 0.05 to 0.5. It is a laminated film for mold release.

  In the above release film, the resin composition layer (B layer) having a heat distortion temperature of 70 to 150 ° C. is a resin composition layer mainly composed of a polyolefin resin.

  Furthermore, the thickness of the whole laminated film (A layer thickness + B layer thickness) is in the range of 40 to 250 μm.

  Since the laminated film for release of the present invention has the above configuration, it has excellent release properties, heat resistance, chemical resistance, hydrolysis resistance, etc., and has the flexibility to follow the circuit steps of the circuit board to the characteristics of the PPS film. Cushioning ability to equalize pressure could be given. Furthermore, there is no outgas or bleed-out substance even if the pressing process is performed for a long time, and the circuit board is not contaminated and the press workability is excellent. The release laminated film of the present invention has become an optimal film for press production release process of rigid multilayer circuit boards, build-up multilayer circuit boards, FPCs, multilayer flexible circuit boards, and circuit boards combining these.

  This invention solves the said subject by laminating | stacking a PPS film on both surfaces of the resin composition layer (B layer) which has specific heat deformation temperature, and controlling a lamination ratio to a specific range.

  In the present invention, the heat distortion temperature refers to the higher of the melting point and the glass transition temperature (peak temperature measured by DSC method), but generally in the case of a crystalline resin composition layer, In the case of an amorphous resin composition layer, it refers to the glass transition temperature.

  In the present invention, the heat-deformation temperature of the resin composition layer is in the range of 70 to 150 ° C. (more preferably 80 to 145 ° C.). It is an important requirement for fitting and making the press pressure uniform. That is, if the temperature is less than 70 ° C., the resin layer oozes out from the end of the release laminate film during hot pressing and adheres to the circuit board or adheres to another (upper and lower) release laminate films. As a result, the workability is significantly reduced. On the other hand, when the temperature exceeds 150 ° C., the flexibility of the release laminate film of the present invention is reduced during hot pressing, making it difficult to follow the steps of the circuit. Furthermore, the uniformity of the heating press pressure is also lacking, causing short circuits between circuits and circuit boards.

  The resin composition layer refers to a sheet or film in which a single organic polymer or several kinds of organic polymers are chemically reacted or mixed. The thickness is preferably in the range of 30 to 250 μm. Also, additives such as inorganic particles, plasticizers, colorants, and other polymers may be added. In that case, it is preferable that it is less than 30 weight% in a layer. This is because the adhesion to the PPS film is lowered or outgas is easily generated during heating.

  Examples of the resin layer include polyester-based, polyolefin-based, acrylic-based, polycarbonate, nylon-based, and acrylic-based, but polyolefin-based resins are particularly preferable in view of chemical resistance, hydrolysis resistance, flexibility, and the like. The resin layer may be unstretched or stretched, but an unstretched sheet is preferred from the viewpoint of thermal dimensional stability. Here, the olefin as referred to in the present invention refers to an olefin basically having an aliphatic hydrocarbon polymer compound composed of carbon atoms and hydrogen atoms as a basic structure. For example, polyethylene, polypropylene, vinyl, etc. These copolymers and those obtained by chemically bonding other derivatives based on hydrocarbon polymers or modified mixtures are also included. For example, an ethylene-ethyl acrylate copolymer (hereinafter sometimes abbreviated as EEA), an ethylene-vinyl acetate copolymer (hereinafter sometimes abbreviated as EVA), and an ethylene-methyl acrylate copolymer. (Hereinafter sometimes abbreviated as EMA), ethylene-methacrylic acid copolymer (hereinafter sometimes abbreviated as EMAA), ethylene-methyl methacrylic acid copolymer (hereinafter sometimes abbreviated as EMMA), ethylene- Examples include acrylic acid copolymers (hereinafter sometimes abbreviated as EAA), ethylene-vinyl alcohol copolymers (hereinafter sometimes abbreviated as EVOH), and the like.

  In addition, the olefin type means that the polymer compound is contained in an amount of 30% by weight or more. In addition, another polymer may be mixed, or a plasticizer, a colorant, an inorganic, an organic filler, or the like may be added. The resin layer (B layer) may be a laminate of several different resin layers as long as the heat deformation temperature is within the range of the present invention.

 The polyphenylene sulfide of the present invention (hereinafter sometimes abbreviated as PPS) is preferably a polymer composed of a structural unit represented by the following formula containing a PPS component of 90 mol% or more, more preferably 95 mol% or more. Say.

  When the PPS component is 90 mol% or more, the crystallinity and thermal transition temperature of the polymer, the melting point, etc. are high, and the heat resistance, dimensional stability, mechanical properties, which are the characteristics of the resin composition containing PPS as the main component, This is because chemical resistance, releasability, etc. can be fully exhibited. More preferably, the PPS is poly-p-phenylene sulfide.

  The PPS resin may contain other copolymerizable units containing sulfide bonds. In this case, the structural unit may be either a random type or a block type copolymerization method.

In the present invention, the resin composition containing PPS as a main component refers to a composition containing 60% by weight or more of PPS. When the content of PPS is less than 60% by weight, the mechanical properties, heat resistance, chemical resistance, hydrolysis resistance, mold release and the like of the layer made of the composition of the laminated film for release of the present invention are impaired. Further, the remaining less than 40% by weight in the composition may contain additives such as polymers other than PPS, inorganic or organic fillers, lubricants, and colorants. Further, the melt viscosity of the PPS composition is preferably 100 to 50000 poise, more preferably 500 to 20000 poise under a temperature of 300 ° C. and a shear rate of 200 sec ⁻¹ . This is because it is easy to form and form a film, and to easily perform lamination processing.

  The biaxially stretched film of the present invention is a film (hereinafter sometimes abbreviated as PPS-BO) obtained by melt-extruding, biaxially stretching and heat-treating the resin composition containing PPS as a main component. Is preferably in the range of 4 to 60 μm.

  In the crystal structure of the PPS-BO of the present invention, it is particularly preferable that the following three parameters measured by the wide angle X-ray diffraction method fall within the following specific ranges.

First, the film thickness uniformity and mechanical properties are those in which the degree of orientation measured from the Edge and End directions (hereinafter sometimes referred to as OF) is in the range of 0.2 to 0.8. From the viewpoint of heat resistance, it is preferable. Here, the degree of orientation measured from the Edge direction (or End direction) is an X-ray plate photograph by X-ray incidence from a direction parallel to the film surface and parallel to the width direction (or longitudinal direction), and PPS Similar to the degree of blackness (Iφ = 0 °) when the intensity of diffraction from the (200) plane of the crystal is scanned on the equator line in the radial direction with a microdensitometer (Iφ = 30). °) ratio Iφ = 30 ° / Iφ = 0 °.
If both of the OFs are less than 0.2, the mechanical properties and thermal dimensional stability are insufficient, while if both of them exceed 0.8, the thickness unevenness of the film is lowered and the heat resistance and hydrolysis resistance are impaired. Sometimes. When one direction is large and the other direction is small, the basic physical properties as a biaxially stretched film may be lowered.

  Second, the size of PPS crystallites in the film (hereinafter sometimes abbreviated as ACS) is preferably in the range of 50 to 100 angstroms from the viewpoints of heat resistance and flexibility of the film at high temperatures. The size of the microcrystal here means the apparent crystal particle size obtained by applying the Scheller equation to the half width of the (200) diffraction peak of the PPS crystal. If the ACS is less than 50 angstroms, there is a decrease in heat resistance such that the film tends to shrink and deform at high temperatures. Conversely, if the ACS exceeds 100 angstroms, embrittlement occurs at high temperatures, and the flexibility of the film tends to decrease significantly.

  Third, a relative crystallization index of 4 or more and 25 or less (more preferably 5 or more and 25 or less) is preferable in terms of dimensional stability at high temperatures and mechanical properties. Here, the relative crystallization index is defined as the ratio I200 / I25 of the maximum intensity (I200) of the (200) diffraction peak of the PPS crystal in the profile by wide-angle X-ray of the film and the intensity (I25) at 2θ = 25 °. Is done. If the relative crystallization index is less than 4, the dimensional change rate at high temperature is large, and conversely, a film having an index exceeding 25 is practically difficult to obtain, and even if obtained, the film becomes quite brittle.

  Furthermore, the heat shrinkage rate (JIS C 2151-1990 edition) of the film at 150 ° C. for 30 minutes is preferably 3% or less for both axes in view of curling prevention during lamination processing and dimensional stability during hot press processing. . Further, it is preferable that the surface of the film is subjected to a surface treatment for easy adhesion such as primer treatment, corona discharge treatment, plasma treatment or the like.

  In the release laminated film of the present invention, PPS-BO (A layer) is laminated on both surfaces of a resin composition layer (B layer) having a heat deformation temperature of 70 to 150 ° C. The release laminated film of the present invention is intended as a release material for the production process of a circuit board. One side of the release material is a release of an adhesive or resin that oozes out from the circuit material, and the other side is a high temperature. It is necessary to release from a press plate (metal plate) or a metal plate used as a spacer, and a PPS film excellent in heat resistance, release property, chemical resistance, hydrolysis resistance, etc. is laminated on both sides. .

  Further, the ratio of the thickness of the A layer to the thickness of the entire laminated film (A layer thickness + B layer thickness) (A layer thickness / (A layer thickness + B layer thickness)) is 0.05. It must be in the range of ~ 0.5. The A layer thickness referred to here is the total thickness of the A layers on both sides of the B layer. More preferably, it is the range of 0.06-0.45. In other words, if the thickness ratio is less than the above lower limit, the surface layer A becomes thin when the overall thickness is reduced, and wrinkles occur during lamination processing, and it is difficult to control film tension during processing, and curling occurs in the laminated film. It is easy to do and lamination workability falls. In addition, the workability of the circuit board pressing process also decreases. On the contrary, when the thickness ratio exceeds the above upper limit, the effect of the core layer (B layer) of the laminated film in which the heat distortion temperature is controlled within a specific range is lowered, and the laminated film for release at the time of hot press This is because the flexibility and cushioning properties are reduced, and the uniformity of the pressing pressure and the followability to the circuit step of the circuit board are lowered.

  The overall thickness of the release laminate film of the present invention is such that the release material handling property (handling property) in the circuit board manufacturing process and the effect of the present invention are the cushioning property of the release laminate film and the circuit step difference. A range of 40 to 250 μm is preferable from the viewpoint of followability and adhesion to the circuit board due to oozing out of the B layer during hot pressing, and workability. More preferably, it is the range of 45-245 micrometers. That is, when the thickness is less than the lower limit, handling in the circuit board manufacturing process is lowered, and heat resistance is also lowered. On the other hand, if the thickness exceeds the above upper limit value, the cushioning effect and follow-up effect referred to in the present invention are lost, or the oozing of the B layer resin softened during the heating press increases and adheres to the circuit board or during the multilayer press. This is because the manufacturing efficiency of the circuit board is lowered due to close contact with another release material. The difference in thickness between the PPS-BO layers on both sides of the release laminate film is preferably within a range of ± 10% in order to suppress curling of the laminate film. Moreover, another layer (a resin film, a fiber sheet, a metal, etc.) may be laminated | stacked on the front and back of the laminated | multilayer film for mold release of this invention.

Next, the manufacturing method of the release laminated film of the present invention will be described.
First, the PPS used for the A layer of the release laminate film of the present invention can use, for example, a method in which an alkali sulfide and p-dichlorobenzene are reacted in a polar solvent under high temperature and high pressure. In particular, it is preferable to react sodium sulfide and p-dichlorobenzene in an amide-based high-boiling polar solvent such as N-methyl-pyrrolidone. In this case, in order to adjust the degree of polymerization, it is most preferable to add a so-called polymerization aid such as a caustic alkali or an alkali metal carboxylate and react at 230 to 280 ° C. The pressure in the polymerization system and the polymerization time are appropriately determined depending on the type and amount of the auxiliary agent used and the desired degree of polymerization. Furthermore, in order to remove the volatile matter etc. of the film finally obtained, the polymer (generally in powder form) is thoroughly washed with water, hot water or organic solvent not containing metal ions, and a by-product salt during polymerization. It is preferable to remove the polymerization aid.

  Inert inorganic particles and the like are mixed with the PPS polymer thus obtained to produce a PPS resin composition. In the mixing method, both are mixed and blended with a mixer or the like, and then extruded in a gut shape while being melt-extruded mixed by a melt extruder represented by an extruder, and then cut into pellets. Moreover, what melt-mixed the additive of a high density | concentration previously is pelletized, and this pellet may be diluted with another pellet in which the additive is not mixed and used.

  Next, a method for producing a biaxially stretched PPS film used for the release laminated film of the present invention will be described.

  The PPS resin composition obtained above was vacuum dried at a temperature of 130 to 180 ° C. for 2 to 10 hours, supplied to a melt extruder represented by an extruder, and melted from a slit die such as a T die. The polymer is continuously extruded and then forcibly cooled to obtain an unoriented amorphous sheet. As such forced cooling means, a method of casting on a cooled metal drum and cooling and solidifying the molten polymer below the glass transition point of PPS is most preferable because there is little thickness variation.

  The sheet thus obtained is stretched biaxially. As a stretching method, a sequential biaxial stretching method, a tenter method or a simultaneous biaxial stretching method using a tubular method can be used. The stretching conditions for controlling the orientation degree OF, ACS, and relative crystallization index of the biaxially stretched PPS film referred to in the present invention to a suitable range are slightly different depending on the properties of the polymer used and the stretching method. In the case of the stretching method, the stretching temperature is preferably in the range of 85 to 105 ° C. and the stretching ratio in the range of 1.5 to 4.5 in both the longitudinal direction and the width direction of the film.

  The biaxially stretched PPS film thus obtained is further heat-treated under a constant length or a limited shrinkage of 15% or less (a heat treatment under a restricted shrinkage is particularly preferred). The heat treatment temperature is preferably 240 ° C. to the melting point of the polymer and the time is in the range of 1 to 60 seconds.

  Next, preferred resins for the layer B of the present invention are olefin resins, such as polyethylene, polypropylene, and derivatives and mixtures thereof, which are commercially available such as EVA, EEA, EMA, EMAA, EMMA, EVOH. A sheet can be obtained by purchasing a sheet, a film, a pellet-like polymer, melting and extruding to a melting point or higher with a melt extruder represented by an extruder, quenching with a cooling roll, and casting. When a lubricant, a colorant, a plasticizer or the like is added, it can be uniformly mixed with a mixer or the like before melt extrusion molding.

Next, the release laminated film of the present invention is produced. As the production method, a dry laminating method in which an olefin resin sheet (B) and PPS-BO (A) are superposed in the order of A / B / A and heat-pressed or hot-rolled via an adhesive. There are two methods, namely, an extrusion laminating method in which the A layer is pressed and laminated on both sides of the layer while the B layer is extruded into a sheet by a melt extruder. When the A and B layers are heat-sealed by the dry laminating method, the films and sheets of each layer are superposed in the order of A / B / A, and the temperature is equal to or higher than the thermal deformation temperature of the B layer, 1 to 10 kg / cm ² . It is heat-sealed with a hot plate press under pressure or continuously with a hot press roll. When an adhesive is used, a solvent-based or solvent-free adhesive is applied to one side of the A layer or both sides of the B layer. As a coating method, a known method such as a gravure roll method, a reverse roll method, a die method, or a comma method can be used. When drying of a solvent is required, the range of 60-120 degreeC is preferable. The thickness of the adhesive is preferably in the range of 1 to 10 μm from the viewpoint of adhesion and workability. The adhesive used is preferably acrylic, olefin, epoxy, silicon, polyester, polyurethane or the like. Using the film or sheet with adhesive obtained above, the films are laminated in the order of A / B / A and press laminated with a heating roll at a temperature equal to or higher than the softening point of the adhesive layer. In the case of using a sheet-like adhesive, a hot plate press or a hot press is applied in the same manner in the order of A / B / A after being previously laminated on one side of the A layer or both sides of the B layer with a hot plate press or a heating roll. It can be laminated with a roll. The extrusion laminating method is a method of laminating B layers between two layers of PPS-BO immediately after being melt-extruded from a melt-extrusion die and then cold-roll pressing, or the same melting for one layer of PPS-BO. There is also a method in which, after extrusion lamination, the same B layer is melt-extruded between the B layer surface and the other PPS-BO and laminated integrally. In this case, the pressing pressure is preferably 1 to 10 kg / cm ² . Of course, a method combining the extrusion laminating method and the dry laminating method may be used, and the PPS resin (A) and the resin composition of the B layer are manufactured by a melt composite by a well-known method so as to have an A / B / A configuration. The film may be biaxially stretched. In this case, the B layer may be biaxially oriented, or may be heat-treated under the film forming conditions of the PPS film, and the orientation of the B layer may be melted and unoriented in the heat treatment zone. . Furthermore, it is preferable to apply a surface treatment for easy adhesion to each film, or to use an olefin sheet rich in adhesiveness between the respective layers in order to improve adhesion.

The following examples illustrate the present invention in more detail.
<Physical properties and evaluation methods, evaluation criteria>
(1) Thermal deformation temperature The resin of the peak of the melting point or the glass transition temperature measured by the differential calorimetry (DSC method) by taking out the resin of the B layer from the cross section of the release laminate film under the following conditions. The heat deformation temperature of
Measuring device: DSC7 manufactured by PERKIN ELMER
Assumed conditions: Temperature rising rate 20 ° C./min Sample amount 10 mg.

(2) Lamination ratio of release laminate film (A / A + B)
The cross section of the release film was obtained by taking an electron micrograph under the following conditions, measuring the thicknesses of the A layer and the B layer with a metal ruler, and calculating the lamination ratio.
Measuring device: S-4300 type field emission scanning electron microscope manufactured by Hitachi, Ltd. Measurement conditions: Accelerating voltage 3 kV
Magnification 1000 times in laminated film thickness.

(3) Thickness of laminated film for mold release According to JIS C2151 (1990), an average value measured with 5 or more points with a micrometer (M30, manufactured by Sony Corporation) was used.

(4) Followability Etch the copper foil side of 1 ounce (35 μm) electrolytic copper foil laminated product (Toray single-sided copper-clad polyimide) of polyimide film (25 μm) to a 1 mm width interval (line width 1 mm) to 20 cm A square printed circuit board was created. Meanwhile, a polyimide film (25 μm) coverlay film (Toray polyimide coverlay film H type) was prepared. The coverlay film was also made the size of the above-mentioned printed circuit board, and 1 mmφ holes were appropriately punched out at 10 locations. Ten layers of the adhesive layer side of the cover lay and the circuit side of the printed circuit board were stacked using a release film having the same size as the printed circuit board, and were laminated by a hot plate press. A 60-t hydraulic flat plate (heater heating method: manufactured by GONNO) press was used as the hot plate press, and the release film / coverlay / printed circuit board was repeated 10 layers, and finally a single layer release film was provided. Furthermore, it provided so that the 5 mm-thick stainless steel board might be pinched | interposed into the both sides of the accumulated base material. The pressing temperature was 170 ° C., the pressure was 20 kg / cm ² , and the pressing time was 0.75 hours to achieve a predetermined temperature.

  Under the above conditions, a cover lay is laminated on a printed circuit board, and the interface between the circuit board circuit and the circuit board base is observed at 20 places with a magnifying glass with a magnification of 2 times. The followability to the circuit step was evaluated.

○: Coverlay adhesive is properly contained up to the interface between the circuit and the circuit board base, and the coverlay is also properly adhered along the step of the circuit.
Δ: Although there is a portion where the adhesive is not properly contained in a part of the interface between the circuit and the circuit board base, there is no practical problem.
X: 30% or more of the observed locations include a portion where the coverlay adhesive is not contained up to the interface between the circuit and the circuit board base, and there is a portion where the coverlay is floating at a circuit step.

(5) Cushioning Hot plate pressing is performed in the same manner as in (4) above, and pressure sensitive paper is sandwiched between the upper and lower stainless steel plates and the release film. The uniformity of the pressure at that time was evaluated according to the following criteria by looking at the color change state of the pressure-sensitive paper having the same size as the release film. The pressure sensitive paper used was for Fuji Film Press Scale for ultra-low pressure (two-sheet type).
○: Almost uniformly discolored red.
(Triangle | delta): The pressure is applied equally 80% or more.
X: The part pressurized uniformly is less than 80%.

(6) Releasability By the same method as (4) above, the adhesion between the release film at the 10 holes formed in the cover lay and the printed circuit board on which the cover lay was laminated was confirmed by hand, and the following Judged by criteria.
○: It peels easily with almost no resistance.
Δ: Peeled but slightly resistant.
X: Not peeled off or has considerable resistance even when peeled off.

(7) B layer resin exuding state from release laminate film B layer resin composition softens and stains from end face of release release laminate film after hot pressing in the same manner as (4) above. The state to be taken out was visually observed and judged according to the following criteria.
○: There is no oozing out or a slight oozing, but there is no problem in workability.
Δ: Spilled out but no circuit adhered, and the level of adhesiveness with the top and bottom release laminate films that leaked out was also low so that there was no significant hindrance to workability.
X: A level that would cause troubles in workability because there was a large amount of oozing and adhered to the circuit, or was firmly bonded to the upper and lower release laminate films that had oozed out in the same manner.

(8) Heat resistance Assuming workability for heat-resistant rigid circuit boards, a release film is sandwiched on both sides of the printed circuit board used in (4) above, and a 5 mm thick stainless steel plate is attached to both sides of the substrate. The film was hot-pressed with a 60-ton hot plate press (heater heating method: manufactured by GONNO), and the state of the release film was observed and judged according to the following criteria. The temperature of the hot plate press at this time was 220 ° C., the pressure was 20 kg / cm ² , and the time was 1 hour after reaching the predetermined temperature.
○: The surface of the release film does not melt or deteriorate at all.
Δ: The surface of the release film is partially melted or discolored, but the release film functions.
X: Level at which the surface of the release film melts or deforms, or deteriorates and becomes brittle and does not function as a release material.
(9) Contamination state of the circuit board The surface layer of the circuit board obtained by the method (4) was observed with a microscope at 20 places and judged according to the following criteria. The microscope used for the observation was an OPTIPHOT Nomarski XF-NR manufactured by Nikon, and a field of view with a magnification of 150 was used as an observation area per place.
○: There is no contamination on the circuit board.
Δ: Contaminated part is less than 20%.
X: Contaminated part is 20% or more.

(10) Workability The workability of the circuit board hot pressing process was determined based on the following criteria for handling in the circuit board manufacturing process performed by stacking 10 layers as described in (4) above.
○: Workability before and after pressing is not particularly problematic, and can be efficiently pressed.
[Delta]: Some work is required due to the overlap of 10 layers before pressing and the exudation of layer B after pressing, but the working efficiency is not significantly reduced.
×: The generation of curling of the release material is poor and the flatness is poor, and it takes time to superimpose the 10 layers before pressing, or there is a large amount of B layer seepage after pressing, and it takes considerable time to remove the release material. Work efficiency is greatly reduced.

Example 1
(1) Polymerization of PPS In an autoclave, 32 kg (250 mol, containing 40 wt% of crystal water) of sodium sulfide, 100 g of sodium hydroxide, 36.1 kg (250 mol) of sodium benzoate, and N-methyl-2-pyridone (hereinafter referred to as NMP) 79.2 kg), and gradually heated to 205 ° C. while stirring to remove 7 liters of distillate containing 6.9 kg of water. To the residual mixture, 37.5 kg (255 mol) of 1,4-dichlorobenzene (hereinafter abbreviated as DCB) and 20 kg of NMP were added and polymerized at 250 ° C. for 5 hours. The obtained reaction product was washed 8 times alternately with hot water using ion-exchanged water and NMP, and dried in a vacuum dryer at 80 ° C. for 24 hours. The resulting PPS powder polymer had a melt viscosity of 4100 poise, a glass transition temperature of 90 ° C., and a melting point of 285 ° C.

(2) Preparation of PPS resin composition 1% of calcium carbonate powder having an average particle diameter of 1 μm was added to the PPS powder obtained in (1) above, mixed with a Henschel mixer, and then mixed with a 30 mmφ twin screw extruder. A PPS resin composition pellet was prepared by pushing out in a gut shape at a temperature of 0 ° C., and then cutting it short after cooling in water.
The obtained poly-p-phenylene sulfide resin composition was dried for 7 hours while stirring with a mixer under reduced pressure of 180 ° C. and 10 mmHg.

(3) Production of biaxially stretched PPS film The dried pellets of (3) above are supplied to a 50 mmφ single screw extruder, melted at a temperature of 320 ° C., extruded from a 300 mm slit-shaped T-die, and a surface temperature of 30 ° C. An unstretched PPS sheet having a thickness of about 200 μm was obtained by casting on a mirror surface metal drum. The sheet was guided to a longitudinal stretching apparatus composed of a roll group and stretched 3.6 times in the longitudinal direction at a temperature of 98 ° C. Thereafter, the uniaxially stretched film was guided to a transverse stretching apparatus (tenter), stretched in the width direction at a stretching temperature of 98 ° C. and a stretching ratio of 3.5 times, and heat-treated at a temperature of 270 ° C. for 10 seconds in the subsequent heat treatment chamber. Furthermore, relaxation was performed 5% in the width direction using the same tenter, and a biaxially stretched PPS film having a thickness of 16 μm was obtained.
The orientation degree OF of the film was 0.62 in the Edge direction and 0.68 in the End direction, the crystallite size (CAS) was 72 Å, and the relative crystallization index was 12. The heat shrinkage rate at 150 ° C. for 30 minutes was 1.2% in the longitudinal direction and 0.2% in the width direction. Further, the surface of the film was subjected to a corona discharge treatment of 6000 J / m ² . Further, a urethane-based anchor coating agent was adjusted on one side of the film by a gravure roll method so that the coating amount was 0.2 g / m ² . For the urethane-based anchor coating agent, Takelac A310 (main agent) / Takenate A3 (curing agent) manufactured by Takeda Pharmaceutical was used at a weight ratio of 9/1. Further, ethyl acetate was used as the solvent (the obtained PPS film is referred to as PPS-1).

(4) Preparation of B-layer resin composition An ethylene-vinyl acetate copolymer (EVA), type NUC-3150 manufactured by Nippon Unicar Co., Ltd. was prepared.

(5) Production of release laminated film EVA prepared in (4) was put into an extruder having a 50 mm hole diameter, melt-extruded at a temperature of 250 ° C., and discharged in a sheet form from a straight die lip. Immediately below the discharge polymer, the molten polymer is placed between the two layers of PPS-1 so that it can be extrusion laminated, and immediately after lamination, it is continuously laminated and solidified with a cooling roll press, so that PPS-1 / EVA / PPS A three-layer laminated film of -1 was obtained. The pressing pressure was 3 kg / cm ² and the cooling temperature was 4 ° C. The film width was adjusted to 400 mm and the entire thickness of the release laminated film was adjusted to 120 μm. The lamination ratio A / A + B was 0.27. The thermal deformation temperature of the resin of the B layer was 75 ° C. The obtained laminated film is designated as laminated film-1.

(Example 2)
(1) Preparation of resin composition for layer B Nippon Unicar Co., Ltd. ethylene-ethyl acrylate copolymer (EEA), type N
UC-6170 was prepared.

(2) Manufacture of laminated film for release In the same manner as in Example 1, a three-layer laminated film of PPS-1 / EEA / PPS-1 was obtained. The resin temperature at the time of melt extrusion was 250 ° C. The thickness of the laminated film was adjusted to 120 μm. The heat distortion temperature of the resin of the B layer was 88 ° C. Let the obtained laminated | multilayer film be laminated | multilayer film-2.

Example 3
Nippon Unicar polyethylene (PE), type NUC-8010 was prepared as the resin for the B layer. Using this polymer, a three-layer film of PPS-1 / PE / PPS-1 was obtained by the method of Example 1. The resin temperature during melt extrusion was 320 ° C., and the thickness of the laminated film was adjusted to 120 μm. The heat distortion temperature of the resin of the B layer was 115 ° C. The laminated film thus obtained is designated as laminated film-3.

Example 4
A modified polypropylene (PP-1) of Sumitomo Chemical Polyolefin, trade name: “Tuffsen” T3712, was prepared as the resin for layer B, and a three-layer laminated film of PPS-1 / PP-1 / PPS-1 was prepared by the method of Example 1. Obtained. The resin temperature during melt extrusion was 330 ° C., and the thickness of the laminated film was adjusted to 120 μm. The heat distortion temperature of the resin of the B layer was 135 ° C. The laminated film thus obtained is designated as laminated film-4.

(Example 5)
A modified polypropylene (PP-2) manufactured by Nippon Polyolefin Co., Ltd., trademark: “Adtex” ER3531LA was prepared as the resin for the B layer, and PPS-1 / PP-2 / PPS-1 was prepared in the same manner as in Example 1. A three-layer laminated film was obtained. The resin temperature during melt extrusion was 350 ° C., and the thickness of the laminated film was adjusted to 120 μm. The heat distortion temperature of the resin of the B layer was 148 ° C. The laminated film thus obtained is designated as laminated film-5.

(Comparative Example 1)
A three-layer laminated film of PPS-1 / PP-3 / PPS-1 in the same manner as in Example 1 using Sumitomo Chemical polyolefin-modified polypropylene (PP-3), trademark: “Tuffsen” T3512, as the resin for layer B Got. The resin temperature during melt extrusion was 350 ° C., and the thickness of the laminated film was adjusted to 120 μm. The thermal deformation temperature of the B layer resin layer was 160 ° C. The laminated film thus obtained is designated as laminated film-6.

(Comparative Example 2)
(1) Production of biaxially stretched PPS film A PPS polymer was polymerized in the same manner as in Example 1 to obtain a biaxially stretched film. The discharge amount of molten PPS was controlled to adjust the thickness of the unstretched PPS sheet to 45 μm so that the thickness of the biaxially stretched PPS film was 3.5 μm. The stretch ratio of the film was 3.5 times in both length and width, the heat treatment conditions were 260 ° C., and the time was 10 seconds. Further, the relaxation rate in the width direction was set to 5% as in the first embodiment. Further, a corona discharge treatment of 6000 J / m ² was performed on one side of the film. Take this film with PPS-2.

(2) Production of Release Laminated Film Using the method of Example 3 and the same B-layer resin, a three-layer laminated film of PPS-2 / PE / PPS-2 was produced. The thickness of the laminated film was adjusted to 160 μm, and the lamination ratio (A / A + B) was 0.043. The laminated film thus obtained had a very thin PPS film layer, which was prone to wrinkles during lamination and was not workable. This laminated film is designated as laminated film-7.

(Example 6)
PPS-BO having a thickness of 5 μm was obtained in the same manner as in Example 1 (PPS-3). Using the film, a three-layer laminated film of PPS-3 / PE / PPS-3 was obtained by the method of Example 3. The thickness of layer B was controlled so that the thickness of the laminated film was 160 μm, and the lamination ratio was 0.063. The laminated film thus obtained is designated as laminated film-8.

(Example 7)
PPS-BO having a thickness of 35 μm was obtained in the same manner as in Example 1 (PPS-4). Using the film, a three-layer laminated film of PPS-4 / PE / PPS-4 was obtained by the method of Example 3. The thickness of the laminated film was 160 μm, and the lamination ratio was adjusted to 0.44. The laminated film thus obtained is designated as laminated film-9.

(Comparative Example 3)
PPS-BO having a thickness of 50 μm was obtained by the method of Example 1 (PPS-5). A three-layer laminated film of PPS-5 / PE / PPS-5 was produced by the method of Example 3 using the film. The thickness of the laminated film was 160 μm, and the lamination ratio was adjusted to 0.63. Let the obtained laminated | multilayer film be laminated | multilayer film-10.

(Example 8)
Using PPS-2 (thickness 3.5 μm) created in Comparative Example 2, three layers were stacked in the same manner as in Example 3, and the thickness of Layer B was adjusted to adjust the stack thickness to 38 μm. did. It was easy to get wrinkles at the time of lamination, and the tension control of PPS-2 on the front and back sides was quite difficult and the laminated film was easy to curl. Let the obtained laminated | multilayer film be the laminated | multilayer film-11.

Example 9
Using PPS-3 obtained in Example 6, three layers were laminated in the same manner as in Example 3, and the thickness of the B layer resin layer was controlled to adjust the thickness of the laminated film to 45 μm. Although it was easier to control than the laminated film 11 of Example 8, wrinkles were liable to occur during the lamination process, and it was liable to curl due to the difference in tension between the front and back PPS-3. Let the obtained laminated film be laminated film-12.

(Example 10)
A PPS-4 obtained in Example 7 was produced in the same manner as in Example 3 to produce a three-layer laminated film, and the thickness of the laminated film was adjusted to 245 μm by controlling the thickness of the B layer resin layer. . Let the obtained laminated film be laminated film-13.

(Example 11)
In the same manner as in the laminated film-13 of Example 10, the thickness of the B layer was adjusted so that the laminated film had a thickness of 253 μm. The resulting laminated film was designated as laminated film-14.
To do.

(Comparative Example 4)
A 150 μm thickness of CR-1024, a laminated processed film of Mitsui Chemicals polymethylpentene film (trademark: Opylan), was prepared. The laminated film is designated as laminated film-15. When the thermal deformation temperature of the resin of the B layer of the laminated film was analyzed, it was 91 ° C.

(Comparative Example 5)
PPS-BO having a thickness of 120 μm was obtained in the same manner as in Example 1. Let the obtained film be PPS-5.

(Comparative Example 6)
For comparison, a heat-resistant polyimide film (PI) 25 μm (Toray-DuPont Kapton 100H) was prepared, and a polyurethane resin was anchor-coated on one side of the film in the same manner as in Example 3. PE and extrusion laminate. The total thickness of the obtained PI / PE / PI three-layer laminated film was adjusted to 120 μm. The obtained laminated film was designated as laminated film-16.

(Comparative Example 7)
Using PPS-BO (PPS-4) having a thickness of 35 μm obtained in Example 7, two layers of PPS-4 / EVA were laminated in the same manner as in Example 2. The thickness of the laminated film was adjusted to 120 μm by adjusting the EVA thickness of the B layer. The obtained two-layer laminated film was named laminated film-17.

  The results of evaluation of each example and comparative example are shown in Tables 1 and 2 in comparison.

(Summary)
The laminated film for mold release of the present invention is a circuit required as a mold release material for the circuit board pressing process by taking advantage of the excellent heat resistance, hydrolysis resistance, chemical resistance, mold release characteristics, etc. of the PPS film. It was possible to provide the ability to follow the level difference, cushioning for uniform press pressure, workability, and the like. This indicates that followability and cushioning properties are imparted when compared to the case of each release laminate film of each example of the present invention and the PPS film alone of Comparative Example 5. Further, it can be seen that the heat release property is excellent even when compared with a film using the polyimide film 16 of Comparative Example 6 having a very high heat resistance. Furthermore, compared to the release film using a polymethylpentene sheet that has been used in the past, the heat resistance is improved and the plasticizer in the sheet does not bleed out and contaminate the circuit board. It can be understood by comparing each laminated film shown in the Examples with laminated film-13 of Comparative Example 4. Furthermore, the laminated film for release of the present invention has no change in mechanical properties or discoloration even after the circuit board manufacturing press step, hydrolyzed deterioration of the circuit substrate with respect to water content or adhesive residual solvent, etc., due to residual solvent gas It was also resistant to degradation.

  Moreover, it turns out that it can be set as the laminated | multilayer film for mold release which has followable | trackability, cushioning property, the bleeding property of the resin of B layer, and workability | operativity by setting it as the structure of this invention. From Examples 1 to 6 and Comparative Example 1, the above-described characteristics are balanced by controlling the heat deformation temperature of the resin layer of the B layer to a specific range of 70 to 150 ° C. That is, when the temperature is less than 70 ° C., the resin of the B layer is softened, and the amount of the resin that oozes out from the end face of the release laminate film during pressing increases, and the release laminate films adhere to each other through the resin by hot pressing. Resulting in. For this reason, workability after press working is reduced. On the other hand, when the temperature exceeds 150 ° C., the followability to the level difference of the circuit and the cushioning property are deteriorated, and an electrical defect and an appearance defect of the circuit board occur, and the object of the present invention cannot be achieved.

  Further, the lamination ratio (A / (A + B)) of the PPS film of the surface layer is also a large requirement that works for the balance of the following characteristics, cushioning properties, and workability. This is the same as in Examples 6 and 7 and the comparison. By comparing Examples 2 and 3, it is well understood that the proper range is 0.05 to 0.5. That is, when the ratio is less than 0.05, the processability of the laminated film is lowered, and wrinkles and curls are generated in the laminated film. This defect reduces workability when the circuit board is pressed. On the other hand, when the ratio exceeds 0.5, the followability and cushioning properties referred to in the present invention are deteriorated and cannot be applied to a high-density circuit board.

  Further, the total thickness of the laminated film for release according to the present invention is preferably in the range of 40 to 250 μm from the viewpoint of heat resistance of press working, workability and follow-up of circuit steps, cushioning and B-layer resin oozing. It can be seen from a comparison between Example 3 and Examples 8 to 11 having the same A layer stacking ratio.

  Moreover, the laminated film -17 of Comparative Example 7 is an A / B two-layer laminated film. Compared with each of the three-layer laminated films (A / B / A) shown in the examples of the present invention, the layer on which PPS-BO is not laminated is eluted rapidly, and the circuit board material and the metal plate of the press are separated. It can be seen that the moldability and heat resistance are lowered and the workability of the press working is remarkably lowered, so that the object of the present invention cannot be achieved.

The release laminate film of the present invention is a rigid multilayer circuit board, a build-up multilayer circuit board, a flexible printed wiring board (coverlay, a connector reinforcement plate), a multilayer flexible circuit board, and a circuit board that combines these. It is optimal as a mold material. However, it is not limited to these.

Claims (3)

A laminated film in which a biaxially stretched film (A layer) made of a resin composition mainly composed of polyphenylene sulfide is laminated on both surfaces of a resin composition layer (B layer) having a heat deformation temperature of 70 to 150 ° C. The ratio of the thickness of the A layer to the total thickness of the laminated film (A layer thickness / (A layer thickness + B layer thickness)) is in the range of 0.05 to 0.5. Mold laminated film. The laminated film for mold release according to claim 1, wherein the B layer is a resin composition layer containing a polyolefin resin as a main component. The laminated film for mold release according to claim 1 or 2, wherein the total thickness of the laminated film (A layer thickness + B layer thickness) is in the range of 40 to 250 µm.