Method for producing FRP precursor and method for producing FRP

Abstract

The invention provides a method for manufacturing an FRP precursor and a method for manufacturing FRP, wherein the size change rate of FRP before and after copper foil etching and heat drying is reduced. Specifically, provided is a method for producing an FRP precursor by a step in which a thermosetting resin film is adhered to at least one surface of a sheet-like aggregate, and after the adhesion, a step in which the FRP precursor is conveyed while applying a tension of 1.5-5.5 N / 25 mm to the FRP precursor.

Description

Technical Field

[0001] The present invention relates to a method for producing an FRP precursor and a method for producing FRP. Background Art

[0002] FRP (Fiber Reinforced Plastics) is a composite material that uses materials with high elastic modulus such as fibers as aggregates and adds the aggregates to a base material (matrix) such as plastic to increase strength. It is a composite material that exhibits weather resistance, heat resistance, chemical resistance, and light weight, and is inexpensive, lightweight, and highly durable.

[0003] FRP is used in a wide range of fields by taking advantage of these properties. For example, FRP is used as a structural material for housing equipment, ships, vehicles, and aircraft due to its shapeability and high strength, and is used in a wide range of fields such as electronic equipment due to its insulating properties.

[0004] Examples of methods for manufacturing FRP include: (1) the RTM (Resin Transfer Molding) method of injecting resin into a mold filled with aggregate; (2) the hand lay-up method and spray molding method of laying aggregate and laminating multiple layers while degassing the resin; and (3) the SMC (Sheet Molding Compound) pressing method of compression molding a sheet obtained by pre-mixing aggregate and resin using a mold.

[0005] When FRP is used for printed circuit boards, the thickness of the FRP for printed circuit boards is required to be thinner than that of FRP for other purposes. In addition, the FRP for printed circuit boards is required to have a narrow tolerance range for thickness deviation after FRP molding and high specifications such as no voids.

[0006] Therefore, FRP for printed circuit boards is mostly manufactured by the hand lay-up (HLU) method. The hand lay-up method is a manufacturing method in which a resin varnish in which a resin component is dissolved is applied to aggregate using a coating machine, and the resin varnish is dried to remove the solvent and heat-cured. The following vertical coating method is used in industry: the aggregate is transported to a container in which the resin varnish is placed, and the FRP precursor impregnated with the resin varnish is lifted up in a roll-to-roll manner and transported to a vertical drying furnace (see Patent Document 1).

[0007] However, in recent years, electronic components used in electronic equipment have been required to be further lightweight and miniaturized from the perspective of convenience in use. Printed circuit boards used in electronic components have also been thinned and miniaturized, and the wiring patterns have been refined and the thickness of the insulating layer has been thinned. Therefore, the thinning of FRP is required, and the thinning of the aggregate contained in FRP is gradually required. If the aggregate is gradually thinned in the vertical coating method, when the FRP precursor impregnated with the resin varnish is pulled in a roll-to-roll manner, the weight of the FRP precursor itself sometimes exceeds the load-bearing capacity of the aggregate and breaks.

[0008] On the other hand, as a method other than the vertical coating method, there is known a method for producing an FRP precursor, which comprises the steps of preparing a resin film obtained by forming a thermosetting resin into a film form, bonding aggregates to the resin film, and then performing a heat treatment (see Patent Document 2).

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 01-272416

[0012] Patent Document 2: International Publication No. 2018 / 181513 Summary of the invention

[0013] Problems to be solved by the invention

[0014] The present inventors have conducted in-depth research on the method described in Patent Document 2, and found that in FRP, which is a cured product of an FRP precursor, especially FRP with copper foil, the manufacturing conditions of the FRP precursor affect the "dimensional change rate" before and after "copper foil etching and heating and drying". The dimensional change rate of FRP is usually not a big problem if it is a fixed value and does not change between batches, but if the dimensional change rate itself is small, there is a tendency that the change between batches is also suppressed, so when it is implemented in industry, it is preferred that the dimensional change rate is smaller. Here, a batch refers to a product manufactured under the same conditions.

[0015] Therefore, an object of the present invention is to provide a method for producing an FRP precursor and a method for producing FRP in which the dimensional change rate after etching and heat drying of copper foil of FRP is reduced.

[0016] Means for solving problems

[0017] The present inventors have conducted intensive studies to solve the above problems and have found that the above problems can be solved by the present invention. The present invention includes the following embodiments [1] to [5].

[0018] [1] A method for producing an FRP precursor, the method comprising the steps of attaching a thermosetting resin film to at least one surface of a sheet-like aggregate,

[0019] After the above-mentioned attachment, the method includes a step of conveying the FRP precursor while applying a tension of 1.5 to 5.5 N / 25 mm to the FRP precursor.

[0020] [2] The method for producing an FRP precursor according to [1] above, wherein the thickness of the aggregate is 25 μm or less.

[0021] [3] The method for producing an FRP precursor according to [1] or [2] above, wherein the aggregate has a tensile strength of 20 to 150 N / 25 mm.

[0022] [4] The method for producing an FRP precursor according to any one of [1] to [3] above, wherein the step of attaching a thermosetting resin film to at least one surface of the sheet-like aggregate is carried out under atmospheric pressure.

[0023] [5] A method for producing FRP, comprising the step of curing the FRP precursor obtained by the production method according to any one of [1] to [4] above.

[0024] Effects of the Invention

[0025] According to the present invention, it is possible to provide a method for producing an FRP precursor and a method for producing FRP in which the dimensional change rate after etching and heat drying of copper foil of FRP is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram showing one mode of the method for producing the FRP precursor according to the present embodiment. DETAILED DESCRIPTION

[0027] In the numerical range described in this specification, the upper limit or lower limit of the numerical range can be replaced by the value shown in the embodiment. In addition, the lower limit and upper limit of the numerical range can be arbitrarily combined with the lower limit or upper limit of other numerical ranges. In the expression of the numerical range "AA to BB", the numerical values ​​AA and BB at both ends are included in the numerical range as the lower limit and upper limit, respectively.

[0028] In this specification, for example, a description such as "10 or more" refers to 10 and a value exceeding 10, and this shall prevail even if the values ​​are different. In addition, for example, a description such as "10 or less" refers to 10 and a value less than 10, and this shall prevail even if the values ​​are different.

[0029] In addition, each component and material exemplified in this specification may be used alone or in combination of two or more unless otherwise specified. In this specification, when there are a variety of substances corresponding to each component in the resin composition, the content of each component in the resin composition refers to the total amount of the various substances present in the resin composition unless otherwise specified.

[0030] In the present specification, the "resin component" is defined as all components other than inorganic compounds such as (C) inorganic fillers described later, among the solid contents constituting the resin composition.

[0031] In this specification, "solid content" refers to components other than the organic solvent in the resin composition. That is, the solid content includes substances that are liquid at around 25°C, and also includes substances that are syrupy or waxy at around 25°C.

[0032] Regarding the expression "containing..." described in the present specification, when the substance described at ... can react, it may be contained in a reacted state, may be contained only ..., and may include both forms.

[0033] Any combination of the matters described in this specification is included in the present invention and the embodiments.

[0034] [Method for producing FRP precursor]

[0035] One mode of the present embodiment is a method for producing an FRP precursor, wherein the method comprises the step of attaching a thermosetting resin film (hereinafter sometimes referred to as "resin film") to at least one surface of a sheet-like aggregate to produce the FRP precursor, and after the above-mentioned attachment, the step of conveying the FRP precursor while applying a tension of 1.5 to 5.5 N / 25 mm to the FRP precursor.

[0036] By setting the tension to 1.5 N / 25 mm or more, it is possible to avoid the resin film from penetrating into the aggregates when the aggregates are overlapped. In addition, by setting the tension to 5.5 N / 25 mm or less, it is possible to reduce the dimensional change rate (hereinafter sometimes referred to as the dimensional change rate of FRP) before and after "copper foil etching and heat drying" of the FRP, especially the FRP having copper foil, which is a cured product of the FRP precursor. It is speculated that the dimensional change rate of FRP can be reduced because the manufacturing method of this embodiment can reduce the stress or strain remaining in the FRP precursor.

[0037] From the same viewpoint, the tension is preferably 1.8 to 5.0 N / 25 mm, more preferably 1.8 to 4.5 N / 25 mm, further preferably 1.8 to 4.2 N / 25 mm, and particularly preferably 1.8 to 3.5 N / 25 mm.

[0038] Below, refer to Figure 1 The manufacturing method of the FRP precursor of the present embodiment and the manufacturing apparatus 1 of the FRP precursor that can be used in the manufacturing method are described. It should be noted that the manufacturing apparatus 1 of the FRP precursor is described as an apparatus that attaches a pair of resin films (thermosetting resin films) 54 to both surfaces of the sheet-like aggregate 40, but it can also be an apparatus that attaches one resin film 54 to only one surface of the sheet-like aggregate 40. In this case, Figure 1 In this embodiment, the resin film delivery device 3, the protective film peeling mechanism 4 and the protective film winding device 5 located on the lower side (or upper side) of the aggregate 40 are not required.

[0039] The manufacturing method of the FRP precursor of the present embodiment can be carried out using the manufacturing device 1 of the FRP precursor. The manufacturing device 1 of the FRP precursor is not particularly limited. From the viewpoint of avoiding the operability problems that are easily generated when a vacuum laminator or the like is used, it can be placed under atmospheric pressure, preferably under atmospheric pressure. That is, the step of attaching a thermosetting resin film to at least one surface of the sheet-like aggregate can be implemented under atmospheric pressure. Here, in this specification, "under atmospheric pressure" has the same meaning as "under normal pressure".

[0040] The manufacturing apparatus 1 of the FRP precursor comprises: an aggregate feeding device 2, a pair of resin film feeding devices 3 and 3, a sheet heating and pressing device 6, and an FRP precursor winding device 8. The manufacturing apparatus 1 of the FRP precursor preferably further comprises a sheet pressurizing and cooling device 7, a pair of protective film peeling mechanisms 4 and 4, and a pair of protective film winding devices 5 and 5.

[0041] It should be noted that “after the above-mentioned attachment, the FRP precursor is conveyed while being given a tension of 1.5 to 5.5 N / 25 mm” means that in the FRP precursor manufacturing device 1, a tension of 1.5 to 5.5 N / 25 mm is given to the FRP precursor conveyed from the sheet heating and pressing device 6 to the FRP precursor winding device 8. The tension given to the FRP precursor conveyed from the sheet heating and pressing device 6 to the FRP precursor winding device 8 can be adjusted by changing the winding speed of the FRP precursor winding device 8.

[0042] On the other hand, the tension applied to the aggregates delivered from the aggregate delivery device 2 to the sheet heating and pressing device 6 is preferably the same as the tension applied to the FRP precursor delivered from the sheet heating and pressing device 6 to the FRP precursor winding device 8, and specifically, it is preferably 1.5 to 5.5 N / 25 mm, more preferably 1.8 to 5.0 N / 25 mm, further preferably 1.8 to 4.5 N / 25 mm, particularly preferably 1.8 to 4.2 N / 25 mm, and most preferably 1.8 to 3.5 N / 25 mm. The tension applied to the aggregates delivered from the aggregate delivery device 2 to the sheet heating and pressing device 6 can be adjusted by changing the delivery speed of the aggregate delivery device 2.

[0043] The aggregate feeding device 2 is a device that feeds out the aggregate 40 wound around the roller by rotating the roller around which the sheet-shaped aggregate 40 is wound in a direction opposite to the winding direction. Figure 1 In the process, the aggregate feeding device 2 feeds the aggregate 40 from the lower side of the roller toward the sheet heating and pressing device 6.

[0044] The pair of resin film feeding devices 3, 3 are devices that include a roller on which the resin film 50 with a protective film is wound, and a support mechanism that rotatably supports the roller while applying a predetermined tension to the fed resin film 50 with a protective film, and rotates the roller on which the resin film 50 with a protective film is wound in a direction opposite to the winding direction to feed the resin film 50 with a protective film wound on the roller. Here, the tension applied to the resin film 50 with a protective film is preferably the same as the tension applied to the FRP precursor fed from the sheet heating and pressing device 6 to the FRP precursor winding device 8, and specifically, is preferably 1.5 to 5.5 N / 25 mm, more preferably 1.8 to 5.0 N / 25 mm, further preferably 1.8 to 4.5 N / 25 mm, particularly preferably 1.8 to 4.2 N / 25 mm, and most preferably 1.8 to 3.5 N / 25 mm. The tension applied to the resin film with a protective film 50 can be adjusted by changing the feeding speed of the resin film feeding devices 3 , 3 .

[0045] The resin film with protective film 50 is a sheet-shaped film including a resin film 54 and a protective film 52 laminated on one aggregate-side film surface 54 a of the resin film 54 (the surface on the aggregate 40 side of both surfaces of the resin film 54 ).

[0046] The pair of resin film feeding devices 3, 3 are respectively located on the front surface 40a side and the back surface 40b side of the aggregate 40 to be fed.

[0047] The one-side resin film delivery device 3 is a device that is located on the surface 40a side of the aggregate 40 being delivered, and delivers the resin film 50 with the one-side protective film from the lower side of the roller to the one-side protective film peeling mechanism 4 in a manner that the protective film 52 becomes the aggregate 40 side being delivered.

[0048] Similarly, the other side resin film delivery device 3 is a device located on the back side 40b of the aggregate 40 being delivered, and is a device that delivers the resin film 50 with the protective film on the other side from the upper side of the roller to the other side protective film peeling mechanism 4 in a manner such that the protective film 52 becomes the side of the aggregate 40 being delivered.

[0049] The pair of protective film peeling mechanisms 4, 4 are deflection rollers located on the front surface 40a side and the back surface 40b side of the aggregate 40 to be fed, respectively.

[0050] The one-side protective film peeling mechanism 4 is a mechanism that receives the resin film with a protective film 50 fed from the one-side resin film feeding device 3 and advancing toward the one-side protective film peeling mechanism 4 by the surface of the rotating steering roller, and advances the one-side resin film 54 of the one-side protective film 50 toward the sheet heating and pressing device 6, and advances the one-side protective film 52 toward the one-side protective film winding device 5, thereby peeling the one-side protective film 52 from the one-side protective film resin film 50. As a result, the aggregate side film surface 54a of the one-side resin film 54 is exposed.

[0051] Similarly, the other side protective film peeling mechanism 4 is a mechanism that receives the other side protective film-attached resin film 50 fed from the other side resin film feeding device 3 and advancing toward the other side protective film peeling mechanism 4 using the surface of the rotating steering roller, and advances the other side resin film 54 of the other side protective film-attached resin film 50 toward the sheet material heating and pressing device 6, and advances the other side protective film 52 toward the other side protective film winding device 5, thereby peeling the other side protective film 52 from the other side protective film-attached resin film 50. As a result, the aggregate side film surface 54a of the other side resin film 54 is exposed.

[0052] The pair of protective film winding devices 5 , 5 are winding devices which are respectively located on the surface 40 a side and the back surface 40 b side of the fed aggregate 40 and wind up the protective films 52 , 52 peeled off by the pair of protective film peeling mechanisms 4 , 4 .

[0053] The sheet material heating and pressing device 6 includes a pair of pressure rollers and a mechanism (not shown) for applying a compressive force to the pair of pressure rollers. The pair of pressure rollers have a heater inside so as to be heated at a predetermined set temperature.

[0054] The sheet heating and pressing device 6 presses the resin films 54 , 54 onto the entering aggregate 40 by a pair of rotating pressing rollers to form a sheet-shaped FRP precursor 60 (film pressing step), and delivers the FRP precursor 60 to the sheet press cooling device 7 .

[0055] Specifically, the aggregate 40 delivered from the aggregate delivery device 2 and the resin films 54, 54 delivered from the pair of protective film peeling mechanisms 4, 4 are caused to enter between a pair of pressure rollers in such a manner that the resin films 54, 54 delivered from the pair of protective film peeling mechanisms 4, 4 are respectively laminated on the surface 40a and the back surface 40b of the aggregate 40 delivered from the aggregate delivery device 2.

[0056] At this time, the resin film 54 on one side is laminated on the aggregate 40 in a manner that the aggregate side film surface 54a side of the resin film 54 on one side is bonded to the surface 40a side of the aggregate 40, and the resin film 54 on the other side is laminated on the aggregate 40 in a manner that the aggregate side film surface 54a side of the resin film 54 on the other side is bonded to the back side 40b side of the aggregate 40, and the resin film 54 is impregnated into the aggregate 40 by compression by the sheet material heating and compression bonding device 6, thereby forming the FRP precursor 60.

[0057] The sheet material pressurizing and cooling device 7 includes a pair of cooling and pressing rollers and a mechanism (not shown) for applying a compressive force to the pair of cooling and pressing rollers. The pair of cooling and pressing rollers compress and cool the high-temperature FRP precursor 60 sent out from the sheet material heating and pressing device 6 by the rotating pair of cooling and pressing rollers, and send it to the FRP precursor winding device 8.

[0058] The FRP precursor winding device 8 includes a roller for winding up the sheet-shaped FRP precursor 60 fed from the sheet press cooling device 7 and a driving mechanism (not shown) for rotating the roller.

[0059] The above-described FRP precursor production apparatus 1 operates as follows.

[0060] First, the sheet-shaped aggregate 40 is fed from the aggregate feeding device 2 toward the sheet material heating and pressing device 6. At this time, the front surface 40a and the back surface 40b of the aggregate 40 are exposed.

[0061] On the other hand, the resin film 50 with the protective film on one side is fed from the lower side of the roller of the resin film feeding device 3 on one side to the protective film stripping mechanism 4 on one side so that the protective film 52 becomes the side of the aggregate 40 to be fed. In addition, the resin film 50 with the protective film on the other side is fed from the upper side of the roller of the resin film feeding device 3 on the other side to the protective film stripping mechanism 4 on the other side so that the protective film 52 becomes the side of the aggregate 40 to be fed.

[0062] Next, when the resin film 50 with a protective film on the side to be sent out is turned around the turning roller as the one-side protective film peeling mechanism 4, the one-side protective film 52 is peeled from the resin film 50 with a protective film on one side so that the aggregate-side film surface 54a is exposed, and the one-side resin film 54 advances toward the sheet heating and pressing device 6. Thus, the aggregate-side film surface 54a of the one-side resin film 54 is exposed. Similarly, when the resin film 50 with a protective film on the other side to be sent out is turned around the turning roller as the other-side protective film peeling mechanism 4, the other-side protective film 52 is peeled from the resin film 50 with a protective film on the other side so that the aggregate-side film surface 54a is exposed, and the other-side resin film 54 advances toward the sheet heating and pressing device 6. Thus, the aggregate-side film surface 54a of the other-side resin film 54 is exposed.

[0063] The pair of peeled protective films 52, 52 are respectively wound up by the pair of protective film winding devices 5, 5.

[0064] The aggregate 40 sent out from the aggregate feeding device 2 and the resin films 54, 54 sent out from the pair of protective film peeling mechanisms 4, 4 are made to enter between a pair of pressure rollers in such a manner that the resin films 54, 54 are respectively laminated on the aggregate 40 sent out from the aggregate feeding device 2. Further, under normal pressure, the pair of resin films 54, 54 are pressed against the aggregate 40 by the sheet heating and pressing device 6 to obtain the FRP precursor 60 (film pressing process). At this time, by controlling the temperature of the heating body inside the pair of pressure rollers provided in the sheet heating and pressing device 6, the pair of pressure rollers are maintained at a specified temperature, and heating and pressing are performed simultaneously during the film pressing process.

[0065] It should be noted that, from the viewpoint of easily applying tension to the aggregate, a support roller (not shown) may be appropriately provided between the aggregate feeding device 2 and the sheet heating and pressing device 6.

[0066] Here, in one aspect of the present embodiment, when the resin film is heat-pressed onto the aggregate, from the viewpoint of resin filling property, the temperature of the pressure roller is preferably in the range of +5°C to +35°C, more preferably +8°C to +32°C, and further preferably +10°C to +30°C of the temperature at which the resin film exhibits the lowest melt viscosity. It should be noted that the temperature at which the resin film exhibits the lowest melt viscosity is a value measured using a rheometer, and more specifically, it is a value measured according to the method described in the examples. When the temperature of the pressure roller is within this condition, from the viewpoint of resin filling property, the roll line pressure (in Japanese: ロール線圧) of the pressure roller is preferably 10 to 100 N / cm, more preferably 20 to 100 N / cm, and further preferably 20 to 60 N / cm.

[0067] In another mode of the present embodiment, when the resin film is heat-pressed to the aggregate, even if the temperature of the pressure roller is lower than +5°C, which is the temperature at which the resin film exhibits the lowest melt viscosity, sufficient resin filling can be obtained if the roller line pressure of the pressure roller is 20 to 100 N / cm. The roller line pressure at this time may be 20 to 80 N / cm, 20 to 70 N / cm, or 20 to 60 N / cm.

[0068] In the present embodiment, the temperature at which the resin film exhibits the minimum melt viscosity varies depending on the raw material of the resin film, but is preferably 60 to 150°C, more preferably 80 to 140°C, further preferably 100 to 140°C, and particularly preferably 120 to 140°C from the viewpoint of productivity of the FRP precursor.

[0069] The FRP precursor 60 sent out from the sheet heating and pressure bonding device 6 is further pressurized and cooled by the sheet press cooling device 7 .

[0070] The FRP precursor 60 sent out from the sheet press cooling device 7 is wound up by the FRP precursor winding device 8 .

[0071] [Method for producing FRP]

[0072] The present invention also provides a method for producing FRP, comprising the step of curing (C-stage) the FRP precursor obtained by the method for producing the FRP precursor. In this specification, C-stage refers to a state of forming a C-stage defined in JIS K6900 (1994).

[0073] The conditions for curing the FRP precursor are not particularly limited, but curing is preferably performed by heating at 160 to 250° C. for 15 to 60 minutes.

[0074] It should be noted that, in the case of manufacturing FRP for printed wiring boards, a metal foil is placed on one FRP precursor or a material formed by stacking 2 to 20 FRP precursors, and the layers are stacked at a temperature of 100 to 250° C., a pressure of 0.2 to 10 MPa, and a heating time of 0.1 to 5 hours to form a laminate containing FRP. In this way, it is not necessary to cure the FRP precursor alone, and the FRP precursor can also be cured in a state of being stacked with a metal foil or various resin films.

[0075] Hereinafter, the aggregate and the resin film used for producing the FRP precursor will be described in detail.

[0076] 〔aggregate〕

[0077] As the aggregate, known aggregates used in various laminates for electrical insulating materials can be used. As the material of the aggregate, there can be mentioned: natural fibers such as paper and cotton wool; inorganic fibers such as glass fibers and asbestos; organic fibers such as aromatic polyamide, polyimide, polyvinyl alcohol, polyester, tetrafluoroethylene and acrylonitrile fibers; mixtures thereof, etc. Among them, from the viewpoint of flame retardancy, glass fibers are preferred. As glass fibers, there can be mentioned: glass woven fabrics obtained by bonding woven fabrics or short fibers using E glass, C glass, D glass, S glass, etc. with an organic binder; fibers obtained by mixing glass fibers with cellulose fibers, etc. More preferred is glass woven fabric, and more preferred is glass woven fabric using E glass.

[0078] Aggregate can have any shape such as woven fabric, nonwoven fabric, roving, chopped strand mat or surface mat. It should be noted that the material and shape are selected according to the purpose and performance of the target formed object. One kind can be used alone, or two or more materials and shapes can be combined as needed. As the shape of aggregate, woven fabric is preferred.

[0079] In one embodiment of the present invention, the thickness of the aggregate may be 25 μm or less. If the thickness of the aggregate is 25 μm or less, there is a tendency that the tensile strength of the aggregate is in the range of 20 to 150 N / 25 mm, but even if the aggregate has only this degree of tensile strength, the aggregate will not be torn apart, and the FRP precursor can be manufactured. The thickness of the aggregate may be 3 to 25 μm, 10 to 23 μm, or 10 to 20 μm. The mass per unit area of ​​the aggregate (weight per unit area) may be 7 to 30 g / m 2 , can also be 8 to 25 g / m 2 , can also be 10 ~ 20g / m 2 , can also be 10 ~ 15g / m 2 When the aggregate is a woven fabric, the density of the aggregate can be 50 to 120 strands / 25 mm in length and 50 to 120 strands / 25 mm in width, or 70 to 110 strands / 25 mm in length and 70 to 110 strands / 25 mm in width, or 80 to 105 strands / 25 mm in length and 80 to 105 strands / 25 mm in width. In addition, the tensile strength of the aggregate can be 20 to 150 N / 25 mm, or 40 to 100 N / 25 mm, or 45 to 80 N / 25 mm, or 45 to 65 N / 25 mm.

[0080] 〔Resin film〕

[0081] The resin film used in the manufacturing method of this embodiment is a thermosetting resin film obtained by forming a thermosetting resin composition into a film. The thickness of the resin film is not particularly limited, but is preferably 2 to 40 μm, more preferably 4 to 30 μm, and further preferably 5 to 20 μm.

[0082] The thermosetting resin composition contains at least a thermosetting resin. In addition to the thermosetting resin, as required, it may include: a curing agent, a curing accelerator, an inorganic filler, an organic filler, a coupling agent, a leveling agent, an antioxidant, a flame retardant, a flame retardant aid, a thixotropic agent, a thickener, a thixotropic agent, a flexible material, a surfactant, a photopolymerization initiator, etc., preferably containing at least one selected from them.

[0083] Hereinafter, each component contained in the thermosetting resin composition will be described in order.

[0084] (Thermosetting resin)

[0085] As the thermosetting resin, it is possible to cite: epoxy resin, maleimide compound, modified polyphenylene ether resin, phenolic resin, polyimide resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, amino resin, unsaturated polyester resin, allyl resin, dicyclopentadiene resin, silicone resin, triazine resin, melamine resin, etc. In addition, it is not particularly limited by these, and known thermosetting resins can be used. They can be used alone or in combination of two or more. As the thermosetting resin, it is preferred to include one or more selected from epoxy resin, maleimide compound, modified polyphenylene ether resin, phenolic resin, polyimide resin, cyanate resin and isocyanate resin, and from the viewpoint of operability, formability and manufacturing cost, it is more preferred to include epoxy resin.

[0086] Examples of the epoxy resin include phenolic epoxy resins such as cresol novolac epoxy resins, phenol novolac epoxy resins, naphthol novolac epoxy resins, aralkyl novolac epoxy resins, and biphenyl novolac epoxy resins; and bisphenolic epoxy resins such as bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol AD ​​epoxy resins, bisphenol S epoxy resins, bisphenol T epoxy resins, bisphenol Z epoxy resins, and tetrabromobisphenol A epoxy resins. ; biphenyl epoxy resin, tetramethylbiphenyl epoxy resin, triphenyl epoxy resin, tetraphenyl epoxy resin, naphthol aralkyl epoxy resin, naphthalene diol aralkyl epoxy resin, naphthol aralkyl epoxy resin, fluorene epoxy resin, epoxy resin having a hydrogenated dicyclopentadiene skeleton, epoxy resin having an ethylenically unsaturated group in the skeleton, alicyclic epoxy resin; diglycidyl ether of polyfunctional phenol; hydrogenated products thereof, etc. The epoxy resin may be used alone or in combination of two or more from the viewpoint of insulation reliability and heat resistance.

[0087] Here, the epoxy resin is not particularly limited, and from the viewpoint of imparting flexibility, it may be an epoxy resin having two or more epoxy groups in one molecule and having a structural unit derived from an alkylene glycol having 3 or more carbon atoms in the alkylene group in the main chain. In addition, from the viewpoint of further improving flexibility, the structural unit derived from an alkylene glycol having 3 or more carbon atoms in the alkylene group may be repeated two or more times in succession.

[0088] The alkylene glycol having 3 or more carbon atoms in the alkylene group is preferably 4 or more carbon atoms in the alkylene group. The upper limit of the carbon number of the alkylene group is not particularly limited, but is preferably 15 or less, more preferably 10 or less, and further preferably 8 or less.

[0089] In addition, as the epoxy resin, a halogenated epoxy resin can be used from the viewpoint of flame retardancy.

[0090] (Curing agent)

[0091] As the curing agent, when the thermosetting resin is an epoxy resin, phenolic curing agents, cyanate curing agents, anhydride curing agents, amine curing agents, active ester group-containing compounds and other curing agents for epoxy resins can be cited. It should be noted that, when the thermosetting resin is a resin other than an epoxy resin, a curing agent known as a curing agent for the thermosetting resin can be used. One curing agent can be used alone, or two or more can be used in combination.

[0092] The phenolic curing agent is not particularly limited, and preferably includes cresol novolac curing agents, biphenyl curing agents, phenol novolac curing agents, naphthyl ether curing agents, triazine skeleton-containing phenolic curing agents, etc. Among them, cresol novolac curing agents are preferred.

[0093] The cyanate curing agent is not particularly limited, and examples thereof include bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenylcyanate), 4,4'-ethylenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylene))benzene, bis(4-cyanatephenyl)sulfide, and bis(4-cyanatephenyl)ether.

[0094] The acid anhydride curing agent is not particularly limited, and examples thereof include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like.

[0095] The amine-based curing agent is not particularly limited, and examples thereof include aliphatic amines such as triethylenetetramine, tetraethylenepentamine, and diethylaminopropylamine; and aromatic amines such as m-phenylenediamine and 4,4′-diaminodiphenylmethane.

[0096] In addition, urea resin or the like can also be used as a curing agent.

[0097] When the thermosetting resin composition contains a curing agent, the content thereof is preferably 20 to 150 parts by mass, more preferably 20 to 100 parts by mass, and even more preferably 40 to 100 parts by mass, based on 100 parts by mass of the thermosetting resin.

[0098] It should be noted that the amount of the epoxy resin curing agent is preferably such that the reactive group equivalent ratio of the curing agent is 0.3 to 1.5 equivalents relative to the epoxy equivalent of the epoxy resin of 1. If the amount of the epoxy resin curing agent is within the above range, the degree of curing can be easily controlled and productivity can be improved.

[0099] (Curing accelerator)

[0100] As the curing accelerator, a common curing accelerator used in the curing of the above-mentioned thermosetting resin can be used. For example, when the thermosetting resin is an epoxy resin, the curing accelerator includes: imidazole compounds and their derivatives; phosphorus compounds; tertiary amine compounds; quaternary ammonium compounds, etc. From the viewpoint of promoting the curing reaction, imidazole compounds and their derivatives are preferred.

[0101] Specific examples of imidazole compounds and their derivatives include 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2-phenylimidazole, 1,2-dimethylimidazole, 2-ethyl-1-methylimidazole, 1-ethyl-2-methylimidazole, 2-ethyl-4-methylimidazole, 4-ethyl-2-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 2,4-diamino-6-[2'-methylimidazolyl-(1' )]ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]ethyl-s-triazine and other imidazole compounds; modified imidazole compounds such as isocyanate-masked imidazole (Japanese: イソシアネートマスクイミダゾール), epoxy-masked imidazole (Japanese: エポキシマスクイミダゾール); salts of the above-mentioned imidazole compounds and trimellitic acid such as 1-cyanoethyl-2-phenylimidazolium trimellitate; salts of the above-mentioned imidazole compounds and isocyanuric acid; salts of the above-mentioned imidazole compounds and hydrobromic acid, etc. Among them, modified imidazole compounds are preferred, and isocyanate-masked imidazoles are more preferred. The imidazole compounds may be used alone or in combination of two or more.

[0102] When the thermosetting resin composition contains a curing accelerator, the content thereof is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.5 to 6 parts by mass relative to 100 parts by mass of the thermosetting resin, from the viewpoint of storage stability and physical properties of the thermosetting resin composition.

[0103] (Inorganic filler)

[0104] The inorganic filler can improve the non-transmittance and abrasion resistance and reduce the thermal expansion coefficient.

[0105] Examples of the inorganic filler include oxides such as silicon dioxide, aluminum oxide, zirconium oxide, mullite, and magnesium oxide; hydroxides such as aluminum hydroxide, magnesium hydroxide, and hydrotalcite; nitride-based ceramics such as aluminum nitride, silicon nitride, and boron nitride; natural minerals such as talc, montmorillonite, and saponite; metal particles and carbon particles; molybdic acid compounds such as zinc molybdate, etc. Among them, oxides and hydroxides are preferred, silicon dioxide and aluminum hydroxide are more preferred, and aluminum hydroxide is further preferred.

[0106] In the case where the thermosetting resin composition contains an inorganic filler, its content varies according to the purpose of addition, and is preferably 0.1 to 65% by volume in the solid content of the thermosetting resin composition. For coloring and non-transmission purposes, if it is 0.1% by volume or more, there is a trend that can give full play to the effect. On the other hand, when added for the purpose of increment, by suppressing it to be less than 65% by volume, there is a trend that can suppress the reduction of bonding force, and the viscosity when there is a resin component does not become too high, and it is easy to suppress the trend of reduced operability. From the same point of view, the content of the inorganic filler is more preferably 5 to 50% by volume, and more preferably 10 to 40% by volume. Based on mass, the content of the inorganic filler is preferably 0.1 to 85% by mass in the solid content of the thermosetting resin composition, more preferably 10 to 75% by mass, and more preferably 20 to 65% by mass.

[0107] Here, the solid content in this specification refers to the components in the composition excluding volatile substances such as water and organic solvents described later. That is, the solid content also includes liquid, syrupy and waxy substances at room temperature around 25°C, and does not necessarily mean solid.

[0108] (Coupling agent)

[0109] The inclusion of a coupling agent has the effect of improving the dispersibility of the inorganic filler and the organic filler and improving the adhesion to the aggregate. The coupling agent may be used alone or in combination of two or more.

[0110] As the coupling agent, a silane coupling agent is preferred. Examples of the silane coupling agent include aminosilane coupling agents [e.g., 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, etc.], epoxysilane coupling agents [e.g., 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc.], phenylsilane coupling agents, alkylsilane coupling agents, alkenylsilane coupling agents [e.g., vinyltrichlorosilane, vinyltrimethoxysilane, etc.] The silane coupling agent may be a vinyl silane coupling agent such as ethoxysilane, etc.], an alkynyl silane coupling agent, a haloalkyl silane coupling agent, a siloxane coupling agent, a hydrogen silane coupling agent, a silazane coupling agent, an alkoxy silane coupling agent, a chlorosilane coupling agent, a (meth) acrylic silane coupling agent, an amino silane coupling agent, an isocyanurate silane coupling agent, a urea silane coupling agent, a mercapto silane coupling agent, a sulfide silane coupling agent, and an isocyanate silane coupling agent. Among them, an epoxy silane coupling agent is preferred, and 3-glycidoxypropyltrimethoxysilane is more preferred.

[0111] Furthermore, a so-called titanate coupling agent in which a silane moiety is replaced with a titanate may also be used.

[0112] When the thermosetting resin composition contains a coupling agent, the content thereof is preferably 0.1 to 5 parts by mass, more preferably 0.1 to 4 parts by mass, and still more preferably 0.5 to 3 parts by mass relative to 100 parts by mass of the thermosetting resin. If it is 0.01 parts by mass or more, there is a tendency that the surface of the aggregate and the surface of the filler can be sufficiently coated, and if it is 5 parts by mass or less, there is a tendency that the generation of excess coupling agent can be suppressed.

[0113] (Organic Solvent)

[0114] From the viewpoint of easy handling, the resin composition may further contain an organic solvent. In this specification, a resin composition containing an organic solvent is sometimes referred to as a resin varnish. When forming a resin film, it is preferably used as a resin varnish from the viewpoint of operability.

[0115] The organic solvent is not particularly limited, and examples thereof include: alcohol solvents such as methanol, ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and tripropylene glycol monomethyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, butanone, cyclohexanone, and 4-methyl-2-pentanone; ester solvents such as ethyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate; ether solvents such as tetrahydrofuran; aromatic solvents such as toluene, xylene, and mesitylene; nitrogen-containing solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfoxide, etc. Among them, from the viewpoint of solubility and appearance after coating, ketone solvents are preferred, cyclohexanone, methyl ethyl ketone, and methyl isobutyl ketone are more preferred, and cyclohexanone and methyl ethyl ketone are further preferred.

[0116] The organic solvent may be used alone or in combination of two or more.

[0117] The content of the organic solvent is adjusted so that the solid content of the resin composition is preferably 20 to 85% by mass, more preferably 40 to 80% by mass, from the viewpoint of ease of coating.

[0118] (Method for producing thermosetting resin film)

[0119] First, after adding the above-mentioned thermosetting resin and other components as needed to the above-mentioned solvent, various mixers are used to mix and stir, thereby making a resin varnish. As a mixer, there can be mentioned: mixers of ultrasonic dispersion method, high-pressure collision dispersion method, high-speed rotation dispersion method, bead mill method, high-speed shear dispersion method and rotation and revolution dispersion method. The obtained resin varnish is applied to a carrier film, and unnecessary organic solvents are removed, and then it is semi-cured (B-staged), thereby being able to manufacture a thermosetting resin film (resin film). Here, in this specification, B-staged refers to the state of forming the B-stage defined in JISK6900 (1994).

[0120] Examples of the carrier film include organic films such as polyethylene terephthalate (PET), biaxially oriented polypropylene (OPP), polyethylene, polyvinyl fluoride, and polyimide; films of copper, aluminum, and alloys of these metals; and films whose surfaces have been subjected to a release treatment using a release agent.

[0121] When the produced resin film is rolled up, it is preferable to arrange a carrier film on the surface on which the thermosetting resin composition is applied and semi-cured and roll up the film while sandwiching the thermosetting resin composition, because the workability is good.

[0122] It should be noted that the thickness of the above-mentioned resin film is not particularly limited. When using a resin film thinner than the thickness of the aggregate, one resin film can be attached to one face of the aggregate, or two or more resin films can be attached. In addition, when using two or more resin films, different resin film combinations such as the thermosetting degree of the resin film or the matching composition can be used.

[0123] The FRP precursor can be cut into any size as needed, and then bonded to a specified object as needed and then thermally cured. In addition, the FRP precursor can also be pre-wound onto a roll and used in a roll-to-roll manner.

[0124] Example

[0125] Hereinafter, the present embodiment will be described in detail with reference to examples, but the present embodiment is not limited to the following examples.

[0126] In addition, the tensile strength of the glass woven fabric used in each example was measured by the following method.

[0127] In addition, about the FRP precursor obtained in each example, the dimensional change rate was measured by the following method, and the appearance was evaluated.

[0128] (1. Tensile strength of glass fabric)

[0129] The tensile strength of the glass woven fabric used in each example was measured in accordance with JIS R3420 (2013).

[0130] (2. Dimensional change rate)

[0131] A copper-clad laminate (FRP) was prepared by laminating two FRP precursors prepared in each example with copper foil "3EC-M3-VLP-12" (Mitsui Kinzoku Co., Ltd.) on both sides of the laminate, and press-forming was performed under the conditions of temperature 230°C, pressure 3.0 MPa, and 120 minutes. A total of four identical copper-clad laminates were prepared, and the following operations (1) to (3) were performed on all the copper-clad laminates.

[0132] (1) After cutting out evaluation samples of 240 mm square from the center of the obtained copper-clad laminate, holes with a diameter of 1.0 mm were opened at the four corners (distance from one side: 10.0 mm) of four evaluation samples, and the distance between each hole was measured in the MD direction and the TD direction, and used as a reference (recorded as "L0").

[0133] (2) Next, the copper foil of the evaluation sample with holes prepared in (1) was etched with a cupric chloride solution, dried at 105°C for 30 minutes, and the distance between the holes was measured again (referred to as "L1"). The difference between the distance between the holes (L1) at this time and the distance between the holes (L0) measured in (1) was calculated, and the dimensional change rate was calculated according to the following calculation formula.

[0134] [Mathematical formula 1]

[0135] Dimension change rate (%) = 100 × (L1-L0) / L0

[0136] (3) Finally, the dried evaluation sample obtained in (2) was further dried at 180°C for 1 hour, and the distance between each hole in the MD direction and the TD direction was measured again (referred to as "L2"). The difference between the distance between each hole at this time (L2) and the distance between each hole (L0) measured in (1) was calculated, and the dimensional change rate was calculated according to the following calculation formula.

[0137] In addition, the said dimensional change rate used the average value of 2 sets of MD directions and the average value of 2 sets of TD directions in one evaluation sample, and also used the average value of 4 evaluation samples.

[0138] [Mathematical formula 2]

[0139] Dimension change rate (%) = 100 × (L2-L0) / L0

[0140] (3. Appearance)

[0141] The FRP precursor produced in each example was visually observed and evaluated according to the following evaluation criteria.

[0142] A: The surface of the FRP precursor appears smooth.

[0143] B: Streaks were generated on the surface of the FRP precursor, and it was found that the glass woven fabric was impregnated with the resin film in a folded state.

[0144] C: The glass fabric was torn into pieces and the FRP precursor could not be produced.

[0145] [Manufacturing Example 1] Manufacture of Resin Film 1

[0146] (Preparation of Thermosetting Resin Varnish 1)

[0147] 15 parts by mass of cyclohexanone and 130 parts by mass of methyl ethyl ketone were added to 100 parts by mass of cresol novolac epoxy resin "EPICLON (registered trademark) N-660" (manufactured by DIC Corporation) and 60 parts by mass of cresol novolac resin "PHENOLITE (registered trademark) KA-1165" (manufactured by DIC Corporation), and the mixture was stirred thoroughly to dissolve. 180 parts by mass of aluminum hydroxide, 1 part by mass of coupling agent "A-187" (manufactured by Momentive Performance Materials Co., Ltd.), and 2.5 parts by mass of isocyanate-masked imidazole "G8009L" (curing accelerator, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were added thereto, and the mixture was stirred to dissolve and disperse the mixture, thereby preparing a thermosetting resin varnish 1 having a solid content of 70% by mass.

[0148] (Manufacturing of Resin Film 1)

[0149] The thermosetting resin varnish 1 obtained above was applied to a PET film (G-2; manufactured by DuPont Teijin Films Co., Ltd.) having a width of 580 mm so that the coating width was 540 mm and the thickness after drying was 15 μm, and dried at 100° C. for 3 minutes to prepare a resin film 1. The minimum melt viscosity temperature of the prepared resin film 1 was measured at a temperature increase rate of 3° C. / min using a rheometer “AR-200ex” (manufactured by TA Instruments Japan Co., Ltd., with a 20 mm diameter fixture) and the result was 130° C.

[0150] [Examples 1 to 4 and Comparative Examples 1 to 2] Production of FRP Precursor

[0151] Using the manufacturing apparatus 1 of the FRP precursor, an FRP precursor having a solid content concentration of 76% by mass from a resin film was manufactured. As the resin film, the resin film 1 prepared in Manufacturing Example 1 was used, and as the aggregate, a glass woven fabric (thickness 15 μm, IPC#1017, aggregate width 550 mm, manufactured by Nitto Bosho Co., Ltd.) was used. It should be noted that the resin film was impregnated from both sides of the aggregate.

[0152] In addition, when manufacturing the FRP precursor, the conditions described in Table 1 were adopted. Using the FRP precursor obtained in each example, the appearance was evaluated and the dimensional change rate was measured. The results are shown in Table 1.

[0153] [Comparative Example 3] Production of FRP Precursor by Vertical Coating Method

[0154] An FRP precursor having a solid content concentration of 76% by mass from the thermosetting resin varnish 1 was attempted to be produced using the thermosetting resin varnish 1 and glass woven fabric as an aggregate (thickness 15 μm, IPC#1017, aggregate width 550 mm, manufactured by Nitto Bosho Co., Ltd.) using a vertical coater.

[0155] [Table 1]

[0156] Table 1

[0157]

[0158] *1: In the vertical coating method, the tension applied when the FRP precursor is pulled up after the varnish is impregnated.

[0159] As can be seen from Table 1, the FRP precursors obtained in Examples 1 to 4 are FRP precursors including thin glass woven fabrics, but have excellent appearance and the dimensional change rate of the copper-clad laminates produced from the FRP precursors is small.

[0160] On the other hand, in Comparative Example 1, in which the tension applied to the FRP precursor conveyed from the sheet processing and pressing device 6 to the FRP precursor winding device 8 was 1.0 N / 25 mm, the appearance was poor. In addition, in Comparative Example 2, in which the tension applied to the FRP precursor conveyed from the sheet processing and pressing device 6 to the FRP precursor winding device 8 was 6.0 N / 25 mm, the dimensional change rate was larger than that of the embodiment.

[0161] In Comparative Example 3 using the vertical coating method, after the varnish was applied to the glass fabric, the thin glass fabric broke in the step of pulling the FRP precursor, so that the production of the FRP precursor itself could not be performed.

[0162] Description of Reference Numerals

[0163] 1: FRP precursor manufacturing device

[0164] 2: Aggregate delivery device

[0165] 3: Resin film delivery device

[0166] 4: Protective film peeling mechanism

[0167] 5: Protective film winding device

[0168] 6: Sheet heating and pressing device

[0169] 7: Sheet pressurized cooling device

[0170] 8: FRP precursor coiling device

[0171] 40: Aggregate

[0172] 40a: Surface of aggregate

[0173] 40b: Back side of aggregate

[0174] 50: Resin film with protective film

[0175] 52: Protective film

[0176] 54: Resin film

[0177] 54a: Surface of the resin film on the aggregate side (aggregate side film surface)

[0178] 60: FRP precursor

Claims

1. A method for producing an FRP precursor, the method comprising the steps of attaching a thermosetting resin film to at least one surface of a sheet-like aggregate, After the above-mentioned attachment, the method includes the step of conveying the FRP precursor while applying a tension of 1.5 N / 25 mm to 5.5 N / 25 mm to the FRP precursor.

2. The method for producing a FRP precursor according to claim 1, wherein: The thickness of the aggregate is less than 25 μm.

3. The method for producing a FRP precursor according to claim 1, wherein: The tensile strength of the aggregate is 20N / 25mm to 150N / 25mm.

4. The method for producing a FRP precursor according to claim 1, wherein: The step of attaching a thermosetting resin film to at least one surface of the sheet-like aggregate is carried out under atmospheric pressure. 5 . A method for producing FRP, comprising the step of curing the FRP precursor obtained by the production method according to claim 1 .

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