JP4148747B2 - Laminate production method - Google Patents

Description

【００６４】
本発明における積層板特性評価結果、表１から明らかなように、実施例１〜実施例１０は、板厚精度、成形性、生産性において優れていた。
また、特に実施例１〜４、６および１０は、外観にも優れていた。
【００６５】
【発明の効果】
本発明の方法では、高品質で生産性の高い積層板の製造方法を提供できる。
また、ロールの表面層を弾性材料で構成しているため、プリプレグと金属箔等との接合をより強固に均一に行うことができる。
更に、テンションを掛けながら連続的に硬化させることにより、金属箔外観に優れた積層板を得ることができる。
また、粘着性樹脂を有する金属箔を用いる場合、樹脂バンクの発生を防止することができ、積層板を安定的に製造できる。
また、プリプレグの第１層と第２層を構成する熱硬化性樹脂の反応率を所定の値にした場合、特に板厚精度及び成形性に優れた積層板を得ることができる。
【図面の簡単な説明】
【図１】本発明における積層板の製造工程を示す概略図である。
【図２】本発明におけるプリプレグの一例を模式的に示す断面図である。
【図３】本発明において用いられるロールの一例を示す側面図である。
【符号の説明】
１ プリプレグ供給部
２ プリプレグ
３ 金属箔供給部
４ 金属箔
５ ロール
６ 巻き取り部
７ 予備加熱部
８ 後加熱部
９ ベ−キングロ−ル
１０ 硬化炉
１１ ピンチロ−ル
２０ シート状基材
２１ 第１層
２２ａ 第２層
２２ｂ 第２層
５１ ロール基材
５２ ロール軸
５３ 表面層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a laminated board.
[0002]
[Prior art]
There is a strong demand for miniaturization and higher functionality for printed circuit boards, but price competition is fierce. In particular, multilayer boards used for printed circuit boards, glass cloth base epoxy resin laminates, or glass nonwoven fabrics are used as intermediate layers. As for the laminated board which used the material and the glass woven fabric as the surface layer base material, reduction of a price has become a big subject in all.
In recent years, electrical equipment, electronic equipment, communication equipment, etc. have been digitized and a stable impedance in printed circuit boards has been required. With this, in copper-clad laminates that are the raw materials for printed circuit boards, Thickness accuracy has been required.
[0003]
Conventionally, in the case of laminating a multi-layer laminate used for a printed circuit board, a glass cloth base epoxy resin laminate, or a laminate comprising a glass nonwoven fabric as an intermediate layer base material and a glass woven cloth as a surface layer base material, A multi-stage batch press is generally used in which a number of copper foils, prepregs, printed circuit boards for inner layers, mirror plates, and the like are stacked between the heating plates and are heated and pressed. (For example, see Non-Patent Document 1)
However, in such a multi-stage batch press, the heat history applied to each laminated board during lamination molding differs depending on the position of each laminated board in the hot platen, so in terms of quality such as formability, warpage, and dimensional change rate. Due to the difference, it was difficult to supply products with little variation in quality. Furthermore, since the laminated board is formed at a high pressure of ^{20 to} 100 kg / cm ² , there is a problem that the thickness accuracy cannot be obtained by the resin flow.
Also, multi-stage batch presses require a huge amount of heat to heat and cool jigs required to form laminated plates such as hot plates, cover plates, cushion materials, etc. It was difficult to save energy for the global environment.
[0004]
In addition, horizontal continuous belt presses and the like have been developed as a laminated board with less quality variation and equipment that can save energy. (For example, see Patent Document 1 and Non-Patent Document 1)
However, even with the horizontal continuous belt press method, the formability (particularly the generation of voids) and the copper due to the problem of pressure unevenness and temperature unevenness when sandwiched between belts, the adhesion due to gravity, and the difference in the entrance angle of the material. There have been problems such as variations in the front and back surfaces due to the adhesive strength of the foil, and warpage and dimensional changes due to differences in the tension of the copper foil and the substrate.
[0005]
[Patent Literature]
Japanese Patent Publication No. 3-44574 (p.2-3, Fig. 2)
[Non-Patent Document 1]
Susumu Honda, edited by Masamitsu Aoki, “High Density Printed Wiring Board Mounting Technology”, published by Realize Inc., September 20, 1991, p. 66-72
[0006]
[Problems to be solved by the invention]
The objective of this invention is providing the manufacturing method of a laminated board for providing the laminated board which is excellent in a moldability and has few variations, such as board | plate thickness precision and curvature.
[0007]
[Means for Solving the Problems]
Such an object is achieved by the present invention described in the following (1) to (5).
(1) A method of transferring a prepreg having a resin composition attached to a sheet-like fiber base material and continuously producing a laminated board, wherein one or a plurality of the prepregs are preheated; A process of bonding a metal foil or carrier film having an adhesive resin layer after the heating, a process of joining the prepreg and the metal foil or carrier film with a roll whose surface is made of an elastic material, and a step of post-heating the laminate is, the laminated board after the heating, the step of passing the roll heated to 100 to 200 ° C., the b - the laminate after the step of passing the Le, further while applying a tension, internal A method for producing a laminated board, comprising: a step of continuously heating using a hot air circulation type curing furnace having a plurality of rolls to promote curing.
(2) The method for manufacturing a laminated board according to (1), wherein the inside of the curing furnace is continuously heated while applying a tension of 10 kgf or more before and after the curing furnace to accelerate the curing.
(3) The method for manufacturing a laminated board according to (1) or (2), wherein the transport direction of the prepreg is a vertical direction.
(4) The said prepreg is a manufacturing method of the laminated board in any one of (1) thru | or (3) which has several thermosetting resin layers.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the manufacturing method of the laminated board of this invention is demonstrated in detail based on suitable embodiment shown to an accompanying drawing.
FIG. 1 is a schematic view for explaining a method for producing a laminated board according to the present invention. As shown in FIG. 1, the prepreg 2 supplied from the prepreg supply unit 1 is transferred in the vertical direction while being preheated by the preheating heating unit 7 using a feed roll.
Moreover, the metal foil 4 which has an adhesive resin layer is supplied from the metal foil supply part 3 using a feed roll.
The prepreg 2 and the metal foil 4 having an adhesive resin layer are bonded together by passing between rolls 5 whose surfaces are made of an elastic material. The bonded laminates are post-heated by the post-heating unit 8, further cured by the baking roll 9, and finally the tension is applied by the pinch roll 11 provided in the curing furnace 10 before and after the curing furnace. Then, it is transferred to the winding unit 6 by a feed roll. And a laminated board is continuously manufactured by winding up by the winding-up part 6. FIG.
[0009]
The prepreg used in the present invention is obtained by adhering a resin composition to a sheet-like substrate.
Examples of the sheet-like base material include, for example, glass fiber base materials such as glass woven fabric, glass non-woven fabric, and glass paper, woven fabric and non-woven fabric made of paper, synthetic fibers, etc., metal fibers, carbon fibers, mineral fibers, and the like. The base material of these base materials may be used alone or in combination. Among these, a glass fiber base material is preferable. This improves the rigidity and dimensional stability of the laminate.
[0010]
Examples of the resin constituting the resin composition include thermosetting resins such as epoxy resins, polyimide resins, phenol resins, melamine resins, and phenoxy resins, or thermoplastic resins such as modified resins, polyester resins, and polyamide resins, and natural resins. Examples of the resin include resins. Among these, an epoxy resin is preferable, and a bisphenol A type epoxy resin is particularly preferable. Thereby, electrical insulation and adhesiveness can be improved.
Furthermore, it is preferable to use a bisphenol A type epoxy resin and a novolac type epoxy resin in a weight ratio of 95: 5 to 60:40, particularly preferably 80:20 to 70:30. Thereby, in addition to the said effect, heat resistance can also be improved.
[0011]
You may mix | blend a hardening | curing agent, a hardening accelerator, a filler, etc. with the said resin composition as needed.
Examples of the curing agent include amine compounds such as dicyandiamide, metaphenylenediamine, and diaminodiphenylsulfone, acid anhydrides such as novolak resin, trimellitic anhydride, and benzophenone tetracarboxylic anhydride, and boron trifluoride and monoethylamine. Imidazoles such as amine complex compounds and 2-phenyl-imidazole can be used.
Further, as the curing accelerator, for example, imidazoles such as 2-phenyl-4-methylimidazole and 2-methyl-4-ethyl-imidazole can be used.
[0012]
As said filler, although an inorganic filler and an organic filler can be mentioned, for example, an inorganic filler is preferable. Thereby, characteristics, such as a tracking resistance of a laminated board, heat resistance, and the fall of a thermal expansion coefficient, can be provided.
Examples of the inorganic filler include hydroxides such as aluminum hydroxide and magnesium hydroxide, calcium carbonate, talc, wollastonite, alumina, silica, unfired clay, fired clay, and barium sulfate. Among these, aluminum hydroxide is particularly preferable. Thereby, tracking resistance can be further provided. The inorganic filler is preferably contained in an amount of 50 to 300 parts by weight, preferably 60 to 280 parts by weight, based on 100 parts by weight of the thermosetting resin. If the content is less than the lower limit, the effect of improving tracking resistance may be reduced, and if the content exceeds the upper limit, solderability may be reduced.
[0013]
The prepreg used in the present invention is not particularly limited, but preferably has a plurality of thermosetting resin layers. Thereby, it can design so that each layer may exhibit a different function.
For example, as shown in FIG. 2, it can be comprised from the prepreg 2 which has a three-layer thermosetting resin layer. That is, the prepreg 2 includes a first layer 21 in which a sheet-like base material 20 is impregnated with a thermosetting resin, and second layers 22a and 22b formed by applying the thermosetting resin to both surfaces of the first layer. It has. Thereby, different functions can be imparted between the first layer and the second layer. The interface between the first layer and the second layer may have a continuous structure by mixing them.
[0014]
The thermosetting resin used for the first layer and the second layer may be the same, but those with different conditions are preferred.
The reaction rate of the thermosetting resin of the first layer is preferably higher than the reaction rate of the thermosetting resin of the second layer. Thereby, the plate | board thickness precision of a 1st layer improves a laminated board. Further, the second layer has improved adhesion with the metal foil.
[0015]
The reaction rate of the thermosetting resin in the first layer is not particularly limited, but is preferably 85% or more. Thereby, the plate | board thickness precision of a laminated board further improves. Further, the reaction rate of the thermosetting resin in the second layer is not particularly limited, but is preferably 65% or less. Thereby, adhesiveness with metal foil further improves. Furthermore, the reaction rate of the thermosetting resin in the first layer is preferably 85% or more, and the reaction rate of the thermosetting resin in the second layer is preferably 65% or less. Thereby, in addition to the above two effects, the resin powder is not easily generated by bending the prepreg or the like.
[0016]
As a preferable thing of the said reaction rate, the reaction rate of the thermosetting resin in a 1st layer is 90 to 95%. The reaction rate of the thermosetting resin in the second layer is preferably 20% or less, particularly preferably 0.1 to 20%. Most preferably, the reaction rate of the thermosetting resin in the first layer is 90 to 95%, and the reaction rate of the thermosetting resin in the second layer is 20% or less. Thereby, in addition to the improvement of adhesiveness, the thickness accuracy of a laminated board, generation | occurrence | production prevention of resin powder, the flow out of resin can be prevented and a moldability improves.
[0017]
The reaction rate can be determined by differential scanning calorimetry (DSC). That is, by comparing the area of the exothermic peak due to the DSC reaction for both the unreacted resin and the resin of each layer, it can be obtained by the following formula (I). Note that the measurement may be performed in a nitrogen atmosphere at a heating rate of 10 ° C./min.
Reaction rate (%) = (1-resin reaction peak area / unreacted resin reaction peak area) × 100 (I)
The reaction rate of the prepreg can be controlled by various methods such as heating temperature, heating time, and irradiation with light, electron beam, etc. However, it is possible to control with the heating temperature and heating time simply and accurately. preferable.
[0018]
Examples of the method for adhering the resin composition to the sheet-like substrate include, for example, a method of immersing the sheet-like substrate in a resin varnish, a coating method using various coaters, a spraying method using a spray, a method of spraying a resin composition powder, and the like. Is mentioned. Among these, the method of immersing the resin varnish in the sheet-like substrate is preferable. Thereby, a resin composition can be made to adhere uniformly to a sheet-like base material.
The amount of the resin composition attached is not particularly limited because it varies depending on the fiber material, properties, and weight (per unit area) of the sheet-like fiber base material.
When the prepreg has a plurality of thermosetting resin layers, the resin weight ratio of the second layer / first layer is not particularly limited, but is preferably 0.05 to 2.5, and particularly preferably 0.1 to 2. 0 is preferred. Thereby, the plate thickness accuracy and the embedding property to the unevenness are improved. If the weight ratio exceeds the upper limit, the effect of improving the thickness accuracy after molding may be reduced. If the amount is less than the lower limit, the effect of preventing the formation of residual voids after molding, or mistling or blistering in a hygroscopic solder test may be reduced.
[0019]
The production method of the present invention includes a step of preheating the prepreg. Thereby, a laminated board can be manufactured continuously stably for a long time.
Although the said preheating temperature is not specifically limited, 150-250 degreeC is preferable and especially 170-240 degreeC is preferable. Thereby, the adhesiveness at the time of lamination with a prepreg and metal foil can be improved. Moreover, the prepreg void can be further reduced. When the heating temperature is less than the lower limit value, the adhesion may be lowered, and when the heating temperature exceeds the upper limit value, the resin component of the prepreg may be thermally decomposed. The transfer speed of the prepreg is not particularly limited, but is preferably 0.5 to 20 m / min, and particularly preferably 1 to 10 m / min. Thereby, a laminated board can be produced uniformly, without reducing productivity.
[0020]
The heat transfer area of the heater used in the preliminary heating step is not particularly limited, but is preferably 1 m ² or more, particularly preferably 1.2 to 1.5 m ² . If the heat transfer area is less than the lower limit, the effect of improving the continuous stable formability of the laminate may be reduced. If the upper limit is exceeded, there is an increase in ambient temperature due to excess energy release, and the prepreg It may be difficult to manage the degree of cure.
Although the shape of the said heater is not specifically limited, It is preferable that it is a flat panel shape. Thereby, an effective amount of heat can be given to the prepreg moving in the vertical direction. Moreover, the said heater is although it does not specifically limit, It is preferable that it is a panel heater, such as a far infrared ray which can be heated to 250 degreeC. Thereby, by reducing the melt viscosity of the resin adhering to the prepreg, it is possible to compensate for a shortage of heat during molding by the heating roll, and to prevent molding defects (particularly voids).
[0021]
In the manufacturing method of this invention, it has the process of bonding the metal foil or carrier film which has an adhesive resin layer after the said preheating. When metal foil has an adhesive resin layer, the adhesiveness of metal foil and a prepreg can be improved. Furthermore, the metal foil having an adhesive resin can suppress the formation of banks when laminating the prepreg and the metal foil, thereby preventing voids and wrinkles generated in the laminate. Examples of the metal constituting the metal foil include copper or a copper-based alloy, aluminum, or an aluminum-based alloy. Although the thickness of metal foil is not specifically limited, 9-70 micrometers is preferable and 12-35 micrometers is especially preferable.
Examples of the carrier film include a PET film, a PBT film, a stretched nylon film, a polycarbonate film, a stretched polypropylene film, and a polyimide film. Although the thickness of a carrier film is not specifically limited, 9-50 micrometers is preferable and 12-35 micrometers is especially preferable.
[0022]
Although it does not specifically limit as resin which comprises the said adhesive resin layer, For example, an epoxy resin, a phenoxy resin, etc. can be mentioned.
The resin constituting the adhesive resin layer is preferably a thermoplastic resin such as a phenoxy resin having a weight average molecular weight of 10,000 or more. When the weight average molecular weight is less than 10,000, the continuous formability may deteriorate due to the formation of a resin bank when the prepreg and the metal foil are joined.
[0023]
Furthermore, the resin constituting the adhesive resin layer preferably contains two or more types of epoxy resins, and particularly preferably contains epoxy resins having different molecular weights. Further, a resin containing a bisphenol type epoxy resin having a weight average molecular weight of 10,000 or more, a bisphenol type epoxy resin having an epoxy equivalent of 500 or less, and a curing agent is most preferable. Thereby, the fluidity | liquidity at the time of laminating with a heating roll can be restrained low, and high adhesiveness can be provided to a composition while keeping interlayer thickness. A bisphenol-type epoxy resin alone having a weight average molecular weight of 10,000 or more may be too flexible due to low crosslinking density after curing, and has a high viscosity when used as a varnish of a predetermined concentration. Workability may be reduced. When a bisphenol-type epoxy resin having an epoxy equivalent of 500 or less is used alone, resin stagnation (resin bank) may occur at the time of joining the metal foil and the prepreg, and the continuous moldability may deteriorate. Examples of the curing agent include amine compounds such as dicyandiamide.
[0024]
The resin constituting the adhesive resin layer is a blend of 50 to 70% by weight: 50 to 30% by weight of a bisphenol type epoxy resin having a weight average molecular weight of 10,000 or more and a bisphenol type epoxy resin having an epoxy equivalent of 500 or less. It is preferable. If the bisphenol type epoxy resin having a weight average molecular weight of 10,000 or more is less than the lower limit value, continuous formability may be deteriorated due to the occurrence of a resin bank at the time of joining the prepreg and the metal foil, and if the upper limit value is exceeded, the prepreg is exceeded. There is a case where the adhesion between the metal foil and the metal foil is lowered.
The weight average molecular weight can be measured by GPC, for example. The epoxy equivalent can be measured, for example, by perchloric acid titration.
In addition, although the thickness of the adhesive resin layer to metal foil is not specifically limited, 5-50 micrometers is preferable and 10-30 micrometers is especially preferable.
[0025]
In the manufacturing method of this invention, it has the process of joining the said prepreg, the said metal foil, etc. with the roll by which the surface was comprised with the elastic material. Thereby, joining of a prepreg, metal foil, etc. can be made further uniform.
In the roll 5 whose surface is made of an elastic material, for example, as shown in FIG. 3, the surface layer 53 is made of an elastic material. That is, it has the surface layer 53 comprised with an elastic material in the roll base-material 51 surface peripheral surface. The elastic material is not particularly limited, and examples thereof include various rubbers such as silicon rubber, isoprene rubber, and ethylene-propylene rubber, and various thermoplastic elastomers such as polyamide-based thermoplastic elastomer, polyester-based thermoplastic elastomer, and polyolefin-based thermoplastic elastomer. It is done. Among these, silicone rubber is preferable.
When joining the prepreg and the metal foil in the roll, the surface pressure between the rolls is not particularly limited, but is preferably 5~30kg / cm ^2, in particular 10-15 kg / cm ² is preferred.
Although the temperature of the said roll is not specifically limited, 100-200 degreeC is preferable and especially 120-180 degreeC is preferable.
[0026]
The rubber shore hardness of the surface layer is not particularly limited, but is preferably 50 degrees or more, particularly preferably 70 to 90 degrees. If the rubber shore hardness is less than the lower limit, the durability of the elastic material may be lowered.
The thickness of the surface layer is preferably 0.5 mm or more, particularly preferably 0.5 to 3.5 mm. When the thickness of the surface layer is less than the lower limit value, it may be difficult to uniformly bond the prepreg and the metal foil, and as a result, the appearance of the laminated plate surface may be deteriorated.
[0027]
In the manufacturing method of this invention, it has the process of further post-heating the laminated board obtained at the said process. As a result, it is possible to prevent characteristic deterioration such as poor appearance due to the occurrence of wrinkles on the copper foil surface and poor formability due to the occurrence of voids.
Although the said post-heating temperature is not specifically limited, 120-250 degreeC is preferable and especially 140-230 degreeC is preferable. Thereby, hardening of resin which comprises a laminated board can be accelerated | stimulated. Moreover, the thermal contraction of the copper foil and the prepreg due to heat dissipation before winding up the laminated plate can be suppressed, whereby the appearance at the time of molding (particularly the wrinkles of the metal foil portion) can be improved. If the heating temperature is less than the lower limit, adhesion may be reduced due to insufficient degree of cure, and if it exceeds the upper limit, the peel strength may be reduced due to thermal decomposition of the resin component of the prepreg. .
[0028]
The heat transfer area of the heater used in the post-heating step is not particularly limited, but is preferably 1 m ² or more, and particularly preferably 1.2 to 1.5 m ² . If the heat transfer area is less than the lower limit value, the effect of improving the continuous stable formability of the laminate may be reduced. If the heat transfer area exceeds the upper limit value, the energy cost increases due to excessive energy release and the equipment cost increases. Increase.
Although the shape of the said post-heater is not specifically limited, It is preferable that it is a flat panel shape. Thereby, effective calorie | heat amount can be given to the laminated board obtained by the said process.
Moreover, the said post-heater is although it does not specifically limit, It is preferable that it is a panel heater, such as a far infrared ray which can be heated to 250 degreeC.
[0029]
In the manufacturing method of this invention, it has the process of letting the laminated board post-heated at the said process pass a roll. As a result, it is possible to further prevent deterioration of characteristics such as poor appearance due to the occurrence of wrinkles on the copper foil surface due to rapid cooling of the laminated plate coming out of the post-heating machine, and poor formability due to void generation, and heating. Further, since the curing of the resin layer of the laminate can be further accelerated by contacting the roll surface, it is possible to prevent deterioration of characteristics such as peel strength and heat resistance failure. It is preferable to use a baking roll from the viewpoint of the heating temperature described later.
[0030]
The heating temperature of the roll is not particularly limited, but is preferably 100 to 200 ° C, particularly preferably 120 to 180 ° C. Thereby, hardening of resin which comprises a laminated board can be accelerated | stimulated. Moreover, the thermal contraction of the copper foil and the prepreg due to heat dissipation before winding up the laminated plate can be suppressed, whereby the appearance at the time of molding (particularly the wrinkles of the metal foil portion) can be improved. If the heating temperature is less than the lower limit value, the temperature difference with the laminated plate coming out from the post-heater increases, so that the appearance defect becomes large and the adhesiveness may decrease due to insufficient curing, the upper limit If the value is exceeded, the peel strength may decrease due to thermal decomposition of the resin component of the prepreg.
Wherein b - contact surface heat transfer area of Le is not particularly limited, preferably 0.1 m ² or more, especially 0.3～0.6M ² is preferred. If the contact surface heat transfer area is less than the lower limit value, the effect of promoting the hardening of the laminate may be reduced, and if the upper limit value is exceeded, the roll diameter increases, resulting in excess energy release. This increases energy costs and equipment costs.
[0032]
The manufacturing method of the present invention includes a step of promoting curing by further heating the laminated plate whose curing has been accelerated by the roll of the above step while applying tension. Thereby, since hardening can be accelerated | stimulated while pulling a laminated board, the surface external appearance of a laminated board can be improved especially.
Specifically, for example, it has a step of passing through a hot air circulation type curing furnace having a plurality of rolls inside. In that case, it hardens | cures, applying a tension | tensile_strength with the pinch roll provided before and behind the curing furnace. Thereby, since hardening of the resin layer of the laminated board which passed the baking roll can further be accelerated | stimulated, a peeling strength improvement and a heat resistant improvement can be aimed at. Moreover, the external appearance (wrinkles of the metal foil portion) of the laminate is improved by applying tension and curing. Furthermore, by providing a plurality of rolls in the curing furnace, the effect of reducing warpage can be improved because the laminate is alternately stretched while receiving heat.
[0033]
The shape of the curing furnace is not particularly limited, but a hot air circulation dryer having a plurality of rolls inside is preferable. In particular, a vertical tatami mat drier having a plurality of rolls inside is preferable. As a result, not only the heat energy can be used efficiently, but also by providing a plurality of rolls inside, it is stretched by the rolls in a heated state, so that the warpage can be improved. Also, by providing multiple rolls inside the dryer, multi-stage drying is possible, so the drying length can be increased in a limited space and the equipment cost can be reduced by downsizing the equipment. And energy saving can be achieved.
[0034]
The tension between the pinch rolls provided before and after the curing furnace is not particularly limited, but it is preferably passed through the curing furnace while applying a tension of 10 kgf or more, particularly preferably 20 to 30 kgf. Thereby, since it can extend | stretch, heating a laminated board, the external appearance of a laminated board can be improved. If the tension is less than the lower limit, the effect of improving the appearance (particularly the wrinkles of the metal foil) of the laminated plate that has come out of the curing furnace may be reduced. Wrinkles may easily enter.
[0035]
Although the heating temperature of the said curing furnace is not specifically limited, 100-250 degreeC is preferable and especially 140-220 degreeC is preferable. Thereby, hardening of resin which comprises a laminated board can further be accelerated | stimulated. Moreover, the thermal contraction of the copper foil and the prepreg due to heat dissipation before winding up the laminated plate can be suppressed, whereby the appearance at the time of molding (particularly the wrinkles of the metal foil portion) can be improved. When the heating temperature is less than the lower limit value, the peel strength and the glass transition temperature (Tg) may be lowered due to insufficient degree of curing of the laminated plate that has come out of the curing furnace. Peel strength may decrease due to thermal decomposition of components. [0036]
The drying length of the curing furnace is not particularly limited, but is preferably 20 m or more, particularly preferably 25 to 35 m. If the drying length is less than the lower limit of the previous period, the effect of promoting the curing of the laminate may be further reduced. If the upper limit is exceeded, not only will the peel strength decrease due to excessive curing, but also the curing furnace Therefore, there is a case where the energy cost increases due to the excessive energy release and the equipment cost increases.
[0037]
The transport direction of the prepreg is not particularly limited, but the vertical direction is preferable. As a result, it is possible to prevent wrinkles during lamination due to bending of the prepreg and to prevent abnormal appearance due to bending of the laminated board after lamination.
[0038]
After the hardening is accelerated by the roll, the laminate is continuously wound by a winder. Moreover, it can cut | judge to predetermined length with a cutting machine.
In addition, in the manufacturing method of this invention, it is preferable to transfer a prepreg to a perpendicular direction and to manufacture a laminated board continuously. Thereby, variations in quality such as warpage and dimensional change can be reduced.
[0039]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited to this.
[0040]
(Example 1)
<Create prepreg>
(1) Preparation of varnish 70 parts by weight of a bisphenol A type epoxy resin having an epoxy equivalent of about 450 and 30 parts by weight of a phenol novolac type epoxy resin having an epoxy equivalent of about 190 were dissolved in 100 parts by weight of methyl ethyl ketone. A solution prepared by dissolving 3 parts by weight of dicyandiamide and 0.15 parts by weight of 2-phenyl-4-methylimidazole in 20 parts by weight of dimethylformamide was added to this solution and mixed by stirring. In this way, an epoxy resin varnish for coating glass cloth was prepared.
[0041]
(2) Impregnation and application of thermosetting resin to sheet-like fiber base material A glass cloth having a thickness of 0.08 mm as a sheet-like base material (WEA 116E manufactured by Nittobo Co., Ltd., width) 1060 mm) is impregnated so that the resin solid content is 35 parts by weight with respect to 100 parts by weight of the glass cloth, and is dried in a drying furnace at 170 ° C. for 3 minutes to form a first layer made of a thermosetting resin-impregnated glass cloth. Created.
Next, the above-mentioned thermosetting epoxy resin varnish is applied to each of both surfaces of the first layer so that the resin solid content is 45 parts by weight with respect to 100 parts by weight of the glass cloth. Dry for 5 minutes to make a second layer. Thus, a prepreg composed of the first layer and the second layer formed on both surfaces thereof was obtained.
[0042]
(3) Confirmation of reaction rate The first layer was obtained by impregnating a glass cloth with an epoxy resin varnish as described above and drying it in a drying furnace at 170 ° C. for 3 minutes.
The sample of the second layer was obtained by scraping the surface of the prepreg composed of the first layer and the second layer prepared by the above method.
The exothermic peak was measured with the DSC apparatus (made by TA Instruments) about the sample of each layer. About the area of the exothermic peak due to the curing reaction near 160 ° C., the resin before the reaction and the resin of each layer were compared, and the reaction rate was calculated according to the above formula (I). As a result, the reaction rate of the first layer was 92%, and the reaction rate of the second layer was 40%.
[0043]
<Creation of metal foil having adhesive resin>
100 parts by weight of brominated phenoxy resin (bromination rate 25%, average molecular weight 30000) and 40 parts by weight of bisphenol F type epoxy resin (Epicron 830 manufactured by Dainippon Ink Chemical Co., Ltd.) 3 parts by weight of methoxyimidazole was stirred and dissolved in a mixed solvent of xylene, propylene glycol monomethyl ether and methyl ethyl ketone to obtain an adhesive resin varnish. The obtained varnish was applied to a copper foil having a thickness of 18 μm (FGP manufactured by Nippon Electrolytic Co., Ltd., width: 580 mm) to obtain a metal foil having an adhesive resin. The thickness of the adhesive resin layer was 15 μm.
[0044]
<Formation of laminated plate>
The above-described prepreg is mounted on the prepreg supply unit, and the prepreg is transferred from the upper side to the lower side at a speed of approximately 1.0 m / min as shown in FIG. 1, and 170 ° C. using far infrared heaters from both sides of the prepreg. And preheated with a panel-like preheater (heat transfer area 1.2 m ² ). Moreover, the above-mentioned copper foil was supplied from the horizontal direction with respect to the transfer direction of a prepreg. The prepreg and the copper foil were passed between a pair of rolls heated to 140 ° C. (roll surface pressure: 10 kg / cm ² ). Next, it post-heated at 150 degreeC using the panel-shaped post-heater (heat-transfer area 1.5m < ² >). After that, they were alternately brought into contact with three baking rolls (contact surface heat transfer area 0.4 m ² ) arranged in the vertical direction, passed while heating at 130 ° C., and then applied with a tension of 25 kgf. Curing was accelerated by a curing furnace (dry length 30 m) heated to 0 ° C., and finally a double-sided copper clad laminate having a thickness of 0.15 mm was obtained.
In addition, the roll comprised the surface layer with silicon rubber (Maywa Rubber Industrial Co., Ltd. product: Silic Super H80) having a thickness of 2 mm and a rubber Shore hardness of 80 degrees.
[0045]
(Example 2)
Example 1 was repeated except that the reaction rate of the first layer of the prepreg was 85%.
[0046]
(Example 3)
Example 1 was repeated except that the reaction rate of the first layer of the prepreg was 70%.
[0047]
Example 4
The same procedure as in Example 1 was conducted except that the reaction rate of the second layer of the prepreg was changed to 70%.
[0048]
(Example 5)
The same procedure as in Example 1 was performed except that a post-heater having a heat transfer area of 0.8 m ² was used.
[0049]
(Example 6)
The procedure was the same as Example 1 except that three baking rolls having a contact surface heat transfer area of 0.08 m ² were used.
[0050]
(Example 7)
The same procedure as in Example 1 was conducted except that the baking temperature was 200 ° C.
[0051]
(Example 8)
Example 1 was repeated except that the heating temperature of the curing furnace was 250 ° C.
[0052]
Example 9
The varnish obtained in Example 1 is a sheet-like base material glass cloth having a thickness of 0.08 mm (WEA 116E manufactured by Nittobo Co., Ltd., width: 1060 mm) and the resin solid content is 45 weights with respect to 100 parts by weight of the glass cloth. And then dried in a drying furnace at 170 ° C. for 5 minutes to prepare a thermosetting resin-impregnated glass cloth.
The same procedure as in Example 1 was performed except that the prepreg was used in the laminate forming process.
[0053]
(Example 10)
The same procedure as in Example 1 was performed except that the tension in the curing furnace was 10 kgf.
[0054]
(Example 11)
The same procedure as in Example 1 was performed except that a 25 μm PET film (Diafoil Hoechst, Diafoil S100) was used as the carrier film instead of the metal foil.
[0055]
(Comparative Example 1)
The procedure was the same as Example 1 except that no curing furnace was used.
[0056]
(Comparative Example 2)
The prepreg obtained in Example 1 was assembled into a paper, and a copper foil having a thickness of 18 μm was stacked on top and bottom of one prepreg to form one set, and 200 sets were prepared. They were hot-press molded at a pressure of 40 kgf / cm ² and a temperature of 170 ° C. for 60 minutes. After the thermoforming, the laminated product at each stage was separated to obtain a double-sided copper-clad laminate with an insulating layer thickness of 0.1 mm.
[0057]
The laminated board obtained by each of the above-mentioned examples and comparative examples was subjected to the following evaluation, and the results obtained are shown in Table 1. Each evaluation was performed by the following method. The plate thickness accuracy and formability were measured by using a double-sided copper clad laminate having a size of 500 mm × 500 mm as a sample by removing the copper foil by etching and using only an insulating layer.
<Evaluation of laminated board>
1. Plate thickness accuracy The plate thickness accuracy was set at 36 measurement points in a grid pattern, and the thickness was measured. The average value and range were obtained and used as the plate thickness accuracy.
[0058]
2 Formability Formability was confirmed visually and by an optical microscope to confirm the presence or absence of voids and other abnormalities. Each code is as follows.
◎: No void ○: There is a void of less than 10 μm, but practical use Δ: There is a void exceeding 10 μm of void, impractical use ×: There are many voids [0059]
3 About the board | substrate of external appearance size 500mm x 500mm, the presence or absence of a wrinkle, a dent, a pit, etc. was confirmed visually.
◎: No wrinkles, etc. ○: There are wrinkles of less than 100 μm, but practical use Δ: There are wrinkles of over 100 μm, impractical use ×: There are many wrinkles etc.
4 Copper foil peel strength The 18 μm copper foil peel strength was measured according to JIS C 6481.
[0061]
5 Solder heat resistance For solder heat resistance, only one surface was etched and cut to a size of 50 mm × 50 mm, and then moisture absorption treatment was performed for 1 hour and boiling 2 hours under pressure cooker conditions of 121 ° C. and 2.0 atmospheres. Subsequently, after being immersed in a 260 ° C. solder bath for 30 seconds, the evaluation of swelling and mistling was confirmed visually and with an optical microscope.
[0062]
6 Productivity comparison example 1 (laminated plate obtained by batch press) As the production amount per hour 1.0, the production amount of the laminated plate obtained by the method of Examples 1-10 was compared.
[0063]
[Table 1]

[0064]
As is clear from the results of evaluation of laminated board characteristics in the present invention and Table 1, Examples 1 to 10 were excellent in plate thickness accuracy, formability, and productivity.
In particular, Examples 1 to 4, 6 and 10 were also excellent in appearance.
[0065]
【The invention's effect】
The method of the present invention can provide a method for producing a laminate with high quality and high productivity.
Moreover, since the surface layer of the roll is made of an elastic material, the prepreg can be joined to the metal foil or the like more firmly and uniformly.
Furthermore, the laminated board excellent in the metal foil external appearance can be obtained by making it harden | cure continuously, applying tension.
Moreover, when using metal foil which has adhesive resin, generation | occurrence | production of a resin bank can be prevented and a laminated board can be manufactured stably.
Moreover, when the reaction rate of the thermosetting resin which comprises the 1st layer of a prepreg and a 2nd layer is made into a predetermined value, the laminated board which was excellent in especially plate | board thickness precision and a moldability can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a production process of a laminated board in the present invention.
FIG. 2 is a cross-sectional view schematically showing an example of a prepreg in the present invention.
FIG. 3 is a side view showing an example of a roll used in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Prepreg supply part 2 Prepreg 3 Metal foil supply part 4 Metal foil 5 Roll 6 Winding part 7 Preheating part 8 Post-heating part 9 Baking roll 10 Curing furnace 11 Pinch roll 20 Sheet-like base material 21 1st layer 22a Second layer 22b Second layer 51 Roll substrate 52 Roll shaft 53 Surface layer

Claims (4)

Transferring a prepreg having a resin composition attached to a sheet-like fiber base material, and continuously producing a laminate,
Preheating one or more of the prepregs;
Bonding the metal foil or carrier film having an adhesive resin layer after the heating;
Bonding the prepreg and the metal foil or carrier film with a roll whose surface is made of an elastic material;
A step of post-heating the laminate obtained in the step;
Passing the laminated plate through a roll heated to 100 to 200 ° C. after the heating;
After the step of passing the roll, the laminate has a step of accelerating the curing by continuously heating the laminate using a hot air circulation type curing furnace having a plurality of rolls inside while applying tension. The manufacturing method of the laminated board characterized by these.   The manufacturing method of the laminated board of Claim 1 which heats the inside of a hardening furnace continuously and applies hardening, applying the tension | tensile_strength of 10 kgf or more before and after the said hardening furnace.   The method for manufacturing a laminated board according to claim 1, wherein a transfer direction of the prepreg is a vertical direction.   The method for producing a laminated board according to any one of claims 1 to 3, wherein the prepreg has a plurality of thermosetting resin layers.

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