JP2010137513A - Laminate sheet and printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed circuit board which is superior in thermal conductivity and flexibility and facilitates manufacture. <P>SOLUTION: A laminate sheet L used for forming the printed circuit board having an insulating layer and a circuit layer and constituted by laminating a prepreg sheet layer 1 constituted by carrying an epoxy resin composition 3 containing inorganic filler on a base material sheet 2 in a semi-hardened state and used for forming the insulating layer a metal foil layer M constituted by using a metal foil M and used for forming the circuit layer is characterized in that a woven cloth is used in the base material sheet 2 constituting the prepreg sheet layer 1 and a heat-fusible fiber 20 which has a core-sheath structure and in which core parts is formed of polyester resin and sheath parts are formed of low melting temperature polyester resin having a lower melting temperature than the polyester resin used in the core parts is used as a thread forming the woven cloth. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laminated sheet used to form a printed circuit board having an insulating layer and a circuit layer, and a printed circuit board.

Conventionally, a prepreg sheet in which a glass cloth or the like is used as a base sheet and a semi-cured epoxy resin composition is supported on the base sheet is widely used, and a metal foil such as a copper foil is used for such a prepreg sheet. Laminated sheets in which a prepreg sheet layer and a metal foil layer are formed are widely used as printed circuit board forming materials in electronic component applications.
For example, an epoxy resin composition that forms a prepreg sheet layer while adhering and integrating a plurality of the metal foil layers patterned by etching and forming a circuit layer by stacking them together and performing a hot press. An insulating layer is formed by thermosetting, and a multilayer board in which a plurality of insulating layers and circuit layers are alternately laminated is formed.
The prepreg sheet used for the formation of such a laminated sheet is usually a printed circuit because the glass cloth itself is formed in a state in which a plurality of bundles of glass fibers are tightly woven into a plain and high bending strength. Even if it is preferable to have flexibility in the manufacturing process of the substrate, it is difficult to satisfy the demand.
In contrast to this, in order to impart flexibility to the prepreg sheet, it is conceivable to use a base sheet woven with yarn made of soft resin fibers instead of glass cloth.

By the way, it is known that an epoxy resin composition becomes brittle when it is brought into a semi-cured state called a B stage, and cracks and the like are caused by a slight stress.
Therefore, even if the base sheet itself is made flexible, the epoxy resin composition is removed from the base sheet by the stress applied to the prepreg sheet unless it has excellent adhesion between the base sheet and the epoxy resin composition. There is a risk of falling off.
On the other hand, resin fibers excellent in adhesion to the epoxy resin composition have not been sufficiently studied so far, and it is difficult to impart flexibility to the prepreg sheet.

  In recent years, as shown in Patent Document 1 below, attempts have been made to improve the thermal conductivity of a prepreg sheet using an epoxy resin composition containing an inorganic filler, but the inorganic filler is contained. In the epoxy resin composition, embrittlement in the B-stage state is remarkable as compared with the case where no inorganic filler is included, and it is much more difficult to prevent the resin sheet from falling off.

For this reason, in the prepreg sheet having excellent thermal conductivity in which the epoxy resin composition containing the inorganic filler is supported on the base sheet in a semi-cured state, it is particularly difficult to impart flexibility. It has become.
Therefore, it is difficult to ensure flexibility even in the laminated sheet, and in the printed circuit board using the laminated sheet, there is a possibility that the workability in the production may be hindered.

JP 2008-274046 A

  An object of the present invention is to solve the above problems, and an epoxy resin composition containing an inorganic filler is used to form a printed circuit board having an insulating layer and a circuit layer. A laminate in which a prepreg sheet layer supported on a base sheet in a semi-cured state and used for forming the insulating layer and a metal foil layer used for forming the circuit layer using a metal foil are stacked. An object of the present invention is to provide a printed circuit board that improves the flexibility of the sheet and is easy to manufacture.

  As a result of intensive studies on resin fibers excellent in adhesion to the epoxy resin composition, the present inventors have found that the epoxy resin composition has high adhesion to the polyester resin fiber and has a core-sheath structure. The heat-fusible fiber in which the core part is formed of a polyester resin and the sheath part is formed of a low-melting polyester resin having a lower melting point than the polyester resin used for the core part is an epoxy resin composition. The inventors have found that it is easy to make close contact, and have completed the present invention.

  That is, the present invention relating to a laminated sheet for solving the above problems is used to form a printed circuit board having an insulating layer and a circuit layer, and an epoxy resin composition containing an inorganic filler is semi-cured. A laminated sheet in which a prepreg sheet layer carried on the base sheet in a state and used for forming the insulating layer and a metal foil layer used for forming the circuit layer using a metal foil are laminated. A woven fabric is used for the base material sheet constituting the prepreg sheet layer, and the yarn constituting the woven fabric has a core-sheath structure, and a core portion is formed of a polyester resin. The heat-fusible fiber in which the sheath part is formed with the low melting polyester resin whose melting | fusing point is lower than the polyester resin used for the part is used.

  In addition, the present invention according to a printed circuit board for solving the above-mentioned problems includes a prepreg sheet layer in which an epoxy resin composition containing an inorganic filler is supported on a base sheet in a semi-cured state, and a metal foil A circuit sheet formed by patterning the metal foil layer, and an insulating layer formed by curing the epoxy resin composition; A woven fabric is used as a base sheet of the prepreg sheet layer, and the yarn constituting the woven fabric has a core-sheath structure, and a core portion is formed of a polyester resin. The heat-fusible fiber having a sheath part formed of a low-melting polyester resin having a lower melting point than that of the polyester resin used for the core part is used.

In the laminated sheet of the present invention, a woven fabric is used for the base sheet of the prepreg sheet, and the yarn constituting the woven fabric has a core-sheath structure, and the core is formed of a polyester resin. Since the heat-fusible fiber in which the said sheath part is formed with the low melting point polyester resin whose melting | fusing point is lower than the polyester resin used for this core part is used, a base sheet and an epoxy resin composition are used. Excellent adhesion.
And since this base material sheet is formed with the heat-fusible fiber by which a polyester resin is used, it can form a flexible laminated sheet compared with a glass cloth.
Therefore, even when high thermal conductivity is achieved by using an epoxy resin composition containing an inorganic filler, dropping of the epoxy resin composition is suppressed, and a laminated sheet having excellent flexibility can be obtained.
That is, according to this invention, the softness | flexibility of a laminated sheet is improved and a printed circuit board can be simply manufactured by using this laminated sheet excellent in the softness | flexibility.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing the laminated sheet of the present embodiment. As shown in FIG. 1, the laminated sheet L of the present embodiment includes a prepreg sheet layer using the prepreg sheet 1 and a metal foil M. Are laminated with a metal foil layer made of.
The laminated sheet L is for forming a printed circuit board, the metal foil layer is provided to form a circuit layer of the printed circuit board, and the prepreg sheet layer is insulated from the printed circuit board. Provided to form a layer.

First, the prepreg sheet 1 used for forming the prepreg sheet layer will be described with reference to FIGS.
2 is a cross-sectional view of the prepreg sheet 1 of the present embodiment, and FIG. 3 is a cross-sectional view showing a cross-sectional structure of the heat-fusible fiber used in the prepreg sheet 1 of the present embodiment.

  As shown in FIGS. 1 and 2, the prepreg sheet 1 according to the present embodiment is carried in a state in which a base sheet 2 is impregnated with a semi-cured epoxy resin composition 3 and is in the form of a sheet. Is formed.

  The base sheet 2 is a woven fabric in which yarns 20 made of heat-fusible fibers 20a are used, and the heat-fusible fibers have a core-sheath structure, and the core portion 20a1 is a polyester. The sheath portion 20a2 is formed of a low melting point polyester resin that is formed of resin and has a lower melting point than the polyester resin used for the core portion 20a1.

On this base sheet 2, yarns 20 having a thickness of 50 to 150 μm and formed of the heat-fusible fiber 20 a are plain woven at a weave density of 40 to 80 pieces / inch respectively. A woven fabric is preferably used.
The base sheet 2 preferably has a basis weight of 10 to 50 g / m ² .

  The yarn 20 may be a single yarn made of the heat-fusible fiber, or may be twisted even if a plurality of the heat-fusible fibers are twisted. An “arrangement yarn” may be used, and the heat-fusible fiber 20a constituting the yarn 20 is usually 25 to 300 dTex.

In the present embodiment, the core portion 20a1 is made of a polyester resin such as a polyethylene terephthalate resin, and the sheath portion 20a2 is a low-melting polyester resin having a lower melting point than the polyester resin used for the core portion 20a1. Is used.
Among these, as the material for forming the core portion 20a1, a polyethylene terephthalate resin in which a substantially repeating unit has only a condensed structure of terephthalic acid and ethylene glycol as described below is preferable.

  A polyethylene terephthalate resin not containing a polymerization component other than terephthalic acid and ethylene glycol is preferably used as the material for forming the core 20a1, while the material for forming the sheath 20a2 is isophthalic acid in addition to ethylene glycol and terephthalic acid. It is preferable that it is a low melting-point polyethylene terephthalate resin which contains as a copolymerization component.

In addition, the thread | yarn 20 which comprises the base material sheet 2 does not need to be comprised only with the above heat-fusible fibers 20a, if necessary, natural fibers, such as cotton, wool, silk, polyethylene resin fiber, Synthetic resin fibers such as polypropylene resin fiber, polyamide resin fiber, polyimide resin fiber, and fluorine resin fiber, alumina (aluminum oxide) fiber, silica (silicon dioxide) fiber, alumina-silica composite fiber, boron fiber, glass fiber, rock wool, For example, a yarn obtained by blending inorganic fibers such as those with the heat-fusible fiber 20a may be used.
However, from the viewpoint of obtaining a prepreg sheet rich in flexibility, the base sheet 2 is preferably composed only of the heat-fusible fiber 20a.

The epoxy resin composition 3 supported on the base sheet 2 in a semi-cured state contains an epoxy resin and an inorganic filler.
Whether or not the epoxy resin composition is in a semi-cured state can be determined by using a differential scanning calorimeter (DSC) based on whether or not a thermal change due to the curing reaction of the epoxy resin is observed.

Examples of the epoxy resin used in the epoxy resin composition include a bisphenol type and a novolac type. Examples of the bisphenol type include a bisphenol A type epoxy resin and a bisphenol F type epoxy resin, and Examples thereof include those obtained by modifying these with CTBN, and those having an epoxy equivalent of 180 to 2500 g / eq. In addition, this epoxy equivalent can be calculated | required based on JISK7236.
Of these, a bisphenol A type epoxy resin having an epoxy equivalent of any one of 900 to 2500 g / eq, which is not modified such as CTBN modification, is preferable.
Moreover, as a novolak type thing, a cresol novolak type epoxy resin and a phenol novolak type epoxy resin are mentioned, for example, o-cresol novolak type epoxy resin which has any softening point of 70-90 degreeC may be illustrated. it can. The softening point can be measured by the ring and ball method of JIS K 7234.
These epoxy resins can be contained in the epoxy resin composition alone or in a mixed state.

As the inorganic filler, from the viewpoint of imparting excellent thermal conductivity to the prepreg sheet 1, it is preferable to contain a larger amount of high thermal conductivity.
Examples of such inorganic fillers include boron nitride particles, aluminum nitride particles, silicon nitride particles, gallium nitride particles, aluminum oxide particles, silicon carbide particles, silicon dioxide particles, and diamond particles having a particle size of 10 nm to 100 μm. Can be mentioned.
Among these, boron nitride particles are suitable in that they have a high thermal conductivity while being relatively inexpensive.
The blending ratio of such an inorganic filler is appropriately determined according to the use of the printed circuit board, etc., but the prepreg sheet in which the glass cloth is used as the base sheet causes peeling with a slight stress. From the viewpoint that the effect of the present invention can be more prominent because it is difficult to carry it from the base material, it is preferably blended in the solid content of the epoxy resin composition at a ratio of 40% by volume or more.

In addition, the epoxy resin composition may contain a so-called curing agent or accelerator for curing the epoxy resin.
The curing agent is not particularly limited, and examples thereof include amine curing agents such as diaminodiphenyl sulfone, dicyandiamide, diaminodiphenylmethane, and triethylenetetramine, phenol novolac resins, aralkyl type phenol resins, and dicyclopentadiene modified phenols. Resin, phenolic curing agents such as naphthalene type phenolic resin and bisphenolic phenolic resin, acid anhydrides and the like can be used.
In particular, when the prepreg sheet is strongly required to have electrical insulation, phenol novolac resin, diaminodiphenyl sulfone, and the like are preferable in that it is easy to ensure reliability in electrical characteristics.
The curing accelerator is not particularly limited, but an amine-based curing accelerator such as imidazoles, triphenyl phosphate (TPP), or boron trifluoride monoethylamine is a curing reaction during storage of the prepreg sheet. It is suitable at the point which can suppress progress of this.

  In addition to the above epoxy resin, inorganic filler, curing agent, accelerator, dispersant, tackifier, anti-aging agent, antioxidant, processing aid, stabilizer, antifoaming agent, flame retardant, Rubbers such as thickeners and pigments, and those generally used as plastic compounding chemicals can be appropriately contained in the epoxy resin composition.

  Next, a prepreg sheet 1, a laminated sheet L using the prepreg sheet, and a method for manufacturing a printed circuit board using the laminated sheet L will be described with reference to FIG. 4.

In the manufacturing method of the prepreg sheet 1 in the present embodiment, an epoxy resin varnish in which the epoxy resin composition is liquefied in advance is prepared, and then the manufactured epoxy resin varnish is long as shown in FIG. The prepreg sheet 1 is produced by continuously coating and drying the belt-shaped base sheet.
As a method for producing this epoxy resin varnish, since the softening point of a bisphenol type epoxy resin or a novolac type epoxy resin is usually 120 ° C. or lower, it is heated to a temperature higher than this softening point (for example, 120 ° C. or higher). The method of obtaining a liquid epoxy resin composition by doing is mentioned.
Moreover, it can replace with such a method and can produce a liquid epoxy resin composition using the organic solvent in which an epoxy resin is soluble.
For example, a liquid epoxy resin composition can be prepared by dispersing an epoxy resin, an inorganic filler, a curing agent, an accelerator, and other compounding agents in an organic solvent such as methyl ethyl ketone.

In addition, in FIG. 4, the epoxy resin varnish 3r produced using the organic solvent is applied to the base material sheet 2s continuously drawn from the base material sheet roll 2r in which the belt-like base material sheet 2s is wound up in a roll shape. A mode that it coats continuously with the spray coater 4 is shown.
In this embodiment, after this coating, the base sheet 2s is introduced into the drying furnace 5 in a state where the epoxy resin varnish 3r is supported, and is heated and dried to produce a strip-shaped prepreg sheet 1, The belt-shaped prepreg sheet 1s is wound into a roll shape to form a prepreg sheet roll 1r.

In the case where it is difficult to impregnate the base sheet 2 with the epoxy resin varnish 3r by such coating because the interval between the yarns constituting the base sheet 2s is wide, for example, The base sheet is supported by a film that has been released from the lower surface side, and the film is introduced into the drying furnace 5 together with the base sheet 2s while the epoxy resin varnish 3r is supported on the base sheet 2s. What is necessary is just to heat-dry.
Further, by using a metal foil for forming a metal foil layer in place of the film subjected to the mold release treatment, it is possible to omit the lamination process described later.

As a laminated sheet manufacturing method for manufacturing the laminated sheet L using the strip-shaped prepreg sheet 1s thus obtained, for example, as shown in FIG. 4, the prepreg sheet 1s is fixed to a certain length from a prepreg sheet roll 1r. A temperature at which the prepreg sheet 1 and the metal foil M cut into a predetermined size are superposed on each other after being cut out by a cutting device 6 and then the epoxy resin composition is not completely cured by the hot press 8. What is necessary is just to perform the lamination | stacking process heat-pressed on conditions, and the lamination sheet L in which heat bonding is possible by this can be produced.
Since the metal foil M at this time is used for forming the circuit layer of the printed circuit board, it can be appropriately selected according to the use of the printed circuit board. For general printed circuit boards, electrolytic copper foil, rolled copper foil, electrolytic aluminum foil, rolled aluminum foil, nickel-plated copper foil, aluminum / copper bi-layer clad foil, etc. having a thickness of 5 to 300 μm can be used. .

Next, in order to form a printed circuit board using the obtained laminated sheet L, a circuit pattern to be formed using the etching resist R on the surface of the metal foil layer of the laminated sheet L formed of the metal foil M is formed. Print.
Then, the etching is performed by the etching machine 9a, the metal foil is removed from the portion where the etching resist R is not printed, the circuit layer is formed (patterning), and then the etching resist R is removed by the resist removing device 9b. Let

  The insulating sheet is formed by thermally curing the epoxy resin composition constituting the prepreg sheet layer, for example, by heating the preformed sheet in which the metal foil layer is patterned into a circuit layer, as it is. The printed circuit board P formed and having the circuit layer formed only on one side can be manufactured.

  Also, using the laminated sheet with the metal foil adhered to both sides of the prepreg sheet 1, the above patterning and the thermosetting of the epoxy resin composition are performed, and if necessary, the conduction between the front and back sides through the through hole is performed. Thus, a printed circuit board (double-sided board) in which circuit layers are formed on both sides of the insulating layer can be produced.

Furthermore, as shown in FIG. 4, a multilayer board can be formed using a plurality of preformed sheets in which a circuit layer is formed on the surface of a semi-cured prepreg sheet layer.
In FIG. 4, circuit layers and insulating layers are alternately and repeatedly laminated using three preformed sheets 9, 9 ′, 9 ″, for a total of four circuit layers and three insulating layers. The case where the multilayer board which has is formed is illustrated.

In addition, in the case where a metal base circuit board is formed by adhering a single-sided board, a double-sided board, or a laminated sheet to a copper plate, an aluminum plate, a stainless steel (SUS) plate, etc., the epoxy resin composition is subjected to heat curing. It is also possible to carry out patterning of the metal foil layer.
For example, a laminated sheet having a metal foil layer on one side and an aluminum plate are hot-pressed, and the laminated sheet and the aluminum plate are thermally bonded by the epoxy resin composition constituting the prepreg sheet layer and heated by this hot press. Alternatively, the epoxy resin composition is completely cured by after-curing that can be additionally performed, and after the prepreg sheet layer forms an insulating layer between the metal foil layer and the aluminum plate, the metal foil is etched. Thus, a metal base circuit board can be manufactured by forming a circuit layer.
In addition, the metal plate such as a copper plate for producing the metal base circuit board is not particularly limited in thickness, but usually any one of 0.5 to 3.0 mm can be used.

  The laminated sheet of the present embodiment does not require careful handling when manufacturing a printed circuit board including the case of manufacturing such a metal base circuit board, and therefore, these manufactures are simpler than conventional manufacturing methods. Can be implemented.

For example, handling with a roll-to-roll as shown in FIG. 4 is possible, and improvement in work efficiency can be expected not only during manufacturing but also during processing.
FIG. 4 illustrates the method of cutting the prepreg sheet and then laminating it with the metal foil. However, the prepreg sheet is used in the form of a long strip without being cut, and is also heated together with the roll-shaped metal foil. It is also possible to produce a long belt-like laminated sheet by heat laminating with a thing such as a casting roller.
Thus, the production efficiency of the laminated sheet itself using the epoxy resin composition containing the inorganic filler is not only improved as compared with the case of the conventional laminated sheet, but also by subsequent etching resist patterning and etching. The patterning of the metal foil layer can also be performed in a roll shape, and as a result, the production of the printed circuit board becomes easier than in the past.

  Moreover, even in the housing form of the members in each process, in order to prevent the peeling of the epoxy resin composition, it is possible to reduce the bending radius of the roll winding due to the flexibility of the prepreg sheet and the laminated sheet. It is not necessary to use a thick core material, and the storage space can be reduced.

For this reason, careful handling is required to prevent the epoxy resin composition from falling off the base sheet even when the epoxy resin composition is highly filled with an inorganic filler, for example, 40% by volume or more. And not.
In addition, by carrying out high filling of an inorganic filler in this way, when drilling with a drill etc. with respect to a lamination sheet, it can suppress that resin adhesion arises around the blade and hole of a drill.
Therefore, it is possible to reduce the effort required to remove the deposit when forming a through hole in a double-sided board or multilayer board, and it is possible to carry out drilling with excellent shape accuracy, and also the effort required for through hole plating etc. Can be reduced.

Normally, when a prepreg sheet using a plain woven fabric as a base sheet is used, pressure is concentrated at the portion where the yarns are overlapped during pressing, resulting in misalignment and uneven application of pressure. As a result, the adhesive force tends to vary.
On the other hand, the laminated sheet of the present embodiment uses a heat-fusible fiber in which a polyester resin having a melting point lower than that of the core is used for the sheath of the base sheet of the prepreg sheet. By adopting a press temperature that is equal to or higher than the melting point of the polyester resin having a melting point or close to the melting point, misalignment of the yarn can be suppressed and the adhesive strength can be made uniform.

  Therefore, when a metal base circuit board is manufactured by hot pressing with an aluminum plate after patterning of the metal foil layer, or when a multilayer board is formed, pattern displacement due to misalignment or pressure variation is suppressed. In addition, an improvement in the quality of the printed circuit board can be expected.

  In the present embodiment, the laminated sheet and the printed circuit board are configured as described above, and the case of manufacturing as described above is illustrated, but in addition to the above illustration, when producing a prepreg sheet, It is also possible to provide a step of further improving the adhesion between the base sheet and the epoxy resin composition.

This will be described more specifically. In the laminated sheet of this embodiment, the yarn constituting the base sheet of the prepreg sheet is formed of heat-fusible fibers using a polyester resin.
Usually, polyethylene terephthalate resin has a melting point of 250 ° C. or higher, and other polyester resins are similarly heated to a melting temperature of epoxy resin or a drying temperature for volatilizing an organic solvent (for example, 100 to 160 ° C.). It has a higher melting point.
Therefore, for example, even when an epoxy resin varnish is produced by a method using an organic solvent and dried at a temperature of 100 to 160 ° C., the epoxy resin varnish is obtained by thermally melting the epoxy resin at a heating temperature of about 100 to 160 ° C. Even when manufactured, there is a sufficiently low possibility of causing a problem in supporting the substrate sheet.

Further, the heat-fusible fiber constituting the base sheet has a core-sheath structure, and the sheath 20a2 is composed of a low-melting polyester resin having a lower melting point than the polyester resin used for the core 20a1. Therefore, the adhesiveness of a base material sheet and an epoxy resin composition can be improved using this difference in melting point.
That is, the contact temperature between the epoxy resin composition and the heat-fusible fiber by contact with the heat-melted epoxy resin varnish or heat when the epoxy resin varnish using the organic solvent is heated and dried on the base sheet, The adhesion between the epoxy resin composition and the heat-fusible fiber can be improved in the vicinity of the melting point of the low-melting polyester resin constituting the sheath 20a2 or higher than the melting point.

  For example, in a fiber that does not have a core-sheath structure and is made of the same resin up to the inside, the inside of the fiber softens when heated to the melting point temperature of the resin constituting the fiber for the purpose of improving adhesion. Therefore, the fiber will be cut, but the base sheet according to the present embodiment is made of the heat-fusible fiber and the epoxy resin composition by adjusting the temperature conditions in the process while suppressing such a fear. Adhesion can be improved.

In other words, the melting point of the low melting point polyester resin constituting the sheath part 20a2 is made sufficiently low than that of the polyethylene terephthalate resin while the core part 20a1 is made of a general polyethylene terephthalate resin having a melting point of 250 ° C. or higher. By setting the temperature to 160 ° C. or lower, even when general conditions are set, the adhesion of the epoxy resin composition to the substrate sheet can be made excellent.
That is, since the melting of the epoxy resin and the drying for volatilizing the organic solvent are usually performed in a temperature range of 100 to 160 ° C., a melting point of 160 ° C. or less (preferably as a resin for constituting the sheath portion 20a2). Can improve the adhesiveness between the base sheet and the epoxy resin composition by adopting a material having a melting point of 140 ° C. or lower.
In addition, about melting | fusing point of this resin, it can obtain | require by measuring a melting peak value by the thermal analysis with the temperature increase rate of 10 degrees C / min using DSC.

  Moreover, in addition to the method for improving the adhesion between the base material sheet and the epoxy resin composition by selecting the material of the core portion 20a1 and the sheath portion 20a2, for example, hot pressing is performed on the prepreg sheet once produced. Therefore, the adhesion can be further improved.

For example, the prepreg sheet is hot-pressed at a temperature not lower than the melting point of the low-melting polyester resin constituting the sheath portion 20a2 and not higher than the melting point of the polyester resin constituting the core portion 20a1, and the base sheet and the epoxy resin composition It is possible to improve the adhesion to objects.
At that time, the degree of curing of the epoxy resin composition (B stage state) can be adjusted at the same time, and the quality of the prepreg sheet can be made uniform.

In this way, a laminated sheet having excellent flexibility can be obtained while the epoxy resin composition containing the inorganic filler is supported in a semi-cured state.
Although not described in detail here, conventionally known technical matters in the laminated sheet and the printed circuit board can also be adopted in the present invention.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.

(Prepreg sheet 1)
An epoxy resin composition containing 60% by volume of aluminum oxide particles has a core-sheath structure, the core is formed of a polyester resin, and has a lower melting point than the polyester resin used in the core Thickness 130 μm × width 20 mm × length 50 mm supported in a semi-cured state on a base sheet (weight per unit 20 g / m ² ) using a heat-fusible fiber having a sheath part formed of a polyester resin A prepreg sheet having a shape was prepared and used as a first prepreg sheet.

(Prepreg sheet 2)
A prepreg sheet having a shape of thickness 130 μm × width 20 mm × length 50 mm was produced without using a base sheet, and was used as a second prepreg sheet.

(Prepreg sheet 3)
A base sheet having the same structure as the base sheet used in the prepreg sheet 1 is used except that polyester fibers not having a core-sheath structure are used. 3 prepreg sheets were prepared.

(Evaluation 1: Bending test)
Each state when the prepreg sheet 1 and the prepreg sheet 2 were bent so as to be bent at an angle of 90 degrees in the middle portion in the length direction was observed.
As a result, while the prepreg sheet 2 was completely broken, the prepreg sheet 1 was seen to be broken like the prepreg sheet 2 to the extent that some cracks were observed in the bent portion. There wasn't.

(Evaluation 2: Adhesive strength test)
A copper foil peeling test piece simulating a printed circuit board by sandwiching a prepreg sheet 1 between an electrolytic copper foil having a thickness of 35 μm and an aluminum plate having a thickness of 2 mm, and performing heat bonding by hot pressing (Example 1) Was made.
Moreover, the test piece for copper foil peeling (comparative example 1) was similarly produced using the prepreg sheet 3. FIG.
About each of these test pieces, the 90 degree | times peeling test of the copper foil was implemented according to JISC6481.
The measurement was performed in two ways: in the initial state and after performing a solder heat resistance test in which the test piece was floated in a 260 ° C. solder bath for 2 minutes.
As a result, the minimum value and the maximum value of the peel strength in each measurement were as shown in Table 1 below.

As can be seen from Table 1, it can be seen that the prepreg sheet used in the laminated sheet of the present invention is excellent in adhesion between the base sheet and the epoxy resin composition.
Moreover, it turns out that there is little variation in the adhesive force of the circuit layer and insulating layer of a printed circuit board by using the lamination sheet of this invention.
As described above, according to the present invention, it is possible to provide a laminated sheet having excellent flexibility while adopting an epoxy resin composition whose thermal conductivity is improved by containing an inorganic filler, and a printed circuit board. It can be seen that the manufacture of can be made easy.

Sectional drawing of the lamination sheet in one Embodiment. Sectional drawing of the prepreg sheet | seat used for the lamination sheet of the embodiment. Sectional drawing showing the heat-fusible fiber currently used for the prepreg sheet. The side view which shows the outline manufacturing process of the lamination sheet and printed circuit board of one Embodiment.

Explanation of symbols

  1: prepreg sheet, 2: base sheet, 3: epoxy resin composition, 20: yarn, 20a: heat-fusible fiber, 20a1: core, 20a2: sheath, L: laminated sheet, M: metal foil, P: Printed circuit board

Claims (10)

Used to form a printed circuit board having an insulating layer and a circuit layer, and an epoxy resin composition containing an inorganic filler is supported on a base sheet in a semi-cured state and used for forming the insulating layer. A prepreg sheet layer and a laminated sheet in which a metal foil is used and a metal foil layer used for forming the circuit layer is laminated,
A woven fabric is used for the base material sheet constituting the prepreg sheet layer, and the yarn constituting the woven fabric has a core-sheath structure, the core is formed of a polyester resin, and is used for the core A laminated sheet comprising a heat-fusible fiber having a sheath part formed of a low-melting-point polyester resin having a lower melting point than the polyester resin used.   The laminated sheet according to claim 1, wherein the proportion of the inorganic filler in the solid content of the epoxy resin composition is 40% by volume or more.   The laminated sheet according to claim 1 or 2, wherein the heat-fusible fiber has a core part formed of a polyethylene terephthalate resin and a sheath part formed of a low melting point polyethylene terephthalate resin containing isophthalic acid as a copolymerization component.   The base material sheet is a woven fabric in which a yarn having a thickness of 50 to 150 µm is woven at a woven density of 40 to 80 pieces / inch. The laminated sheet according to item. A laminated sheet is formed by laminating a prepreg sheet layer in which an epoxy resin composition containing an inorganic filler is supported on a base sheet in a semi-cured state and a metal foil layer in which a metal foil is used. A printed circuit board having a circuit layer formed by patterning the metal foil layer and an insulating layer formed by curing the epoxy resin composition,
A woven fabric is used as the base sheet of the prepreg sheet layer, and the yarn constituting the woven fabric has a core-sheath structure, the core portion is formed of a polyester resin, and is used for the core portion. A printed circuit board comprising: a heat-fusible fiber having a sheath formed of a low-melting polyester resin having a lower melting point than that of the polyester resin.   The printed circuit board according to claim 5, wherein the printed circuit board is a double-sided board having circuit layers on both sides of the insulating layer.   The printed circuit board according to claim 5, wherein the printed circuit board is a multilayer board in which a plurality of the insulating layers and the circuit layers are alternately laminated.   The printed circuit board according to any one of claims 5 to 7, wherein a ratio of the inorganic filler to a solid content of the epoxy resin composition is 40% by volume or more.   9. The heat-fusible fiber according to claim 5, wherein the core part is formed of a polyethylene terephthalate resin and the sheath part is formed of a low melting point polyethylene terephthalate resin containing isophthalic acid as a copolymerization component. A printed circuit board according to 1.   10. The substrate sheet according to claim 5, wherein the base sheet is a woven fabric in which a yarn having a thickness of 50 to 150 μm is woven at a woven density of 40 to 80 pieces / inch. A printed circuit board according to the item.

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