JP6553427B2 - Method for producing reinforced flexible printed wiring board, thermosetting resin composition, and thermosetting adhesive sheet - Google Patents

Description

  The present invention relates to a method for producing a reinforced flexible printed wiring board in which a flexible printed wiring board and a connection base material are adhered via a thermosetting adhesive layer, a thermosetting resin composition, and a thermosetting adhesive sheet.

  It has been practiced to increase the strength of a flexible printed wiring board by backing the terminal portions and the like of the flexible printed wiring board with a connection base material. In this case, generally, the flexible printed wiring board and the connection base material are bonded via a thermosetting adhesive layer.

  As a thermosetting adhesive layer, what consists of an adhesive composition containing a thermoplastic resin, an epoxy resin, an inorganic filler, an imidazole silane, and an imidazole compound is known, for example (refer patent document 1).

  For bonding of the flexible printed wiring board and the connection base, for example, after heat lamination, a method of performing heat pressure (for example, heat pressure of 0.5 MPa or more) and further heat treatment is performed.

JP 2006-176664 A

  In recent years, from the viewpoints of reduction of process load, reduction of equipment investment, improvement of workability, etc., it is required to omit heat and pressure after heat lamination.

  However, when using a highly hygroscopic base material for connection, the moisture and the like in the vaporized base material for connection tends to remain as air bubbles at the adhesive interface of the thermosetting adhesive layer, and the above-mentioned air bubbles are It is difficult to eliminate. When the bubbles remain at the adhesive interface of the thermosetting adhesive layer, it is difficult to obtain sufficient heat resistance.

  The present invention has been proposed in view of such conventional circumstances, and a method for producing a reinforced flexible printed wiring board capable of suppressing air bubbles at the adhesive interface of a thermosetting adhesive layer, a thermosetting resin composition, and a thermosetting resin composition. A curable adhesive sheet is provided.

  The inventors of the present application have found that (meth) acrylic polymer, an epoxy resin having a melt viscosity at 140 to 180 ° C. equal to or less than a predetermined value, and an epoxy resin curing agent It has been found that the above problems can be solved by using a thermosetting resin composition having a predetermined viscosity.

  That is, in the method of producing a reinforced flexible printed wiring board according to the present invention, the step of thermally laminating the flexible printed wiring board and the connection base material at a temperature of 120 to 160 ° C. via a thermosetting adhesive layer; Heat-treating at a temperature of -180 ° C., and the thermosetting adhesive layer comprises (meth) acrylic polymer and an epoxy resin having a melt viscosity of 0.1 Pa · s or less at 140-180 ° C. And an epoxy resin curing agent, and the melt viscosity at 120 to 160 ° C. is formed from a thermosetting resin composition having a viscosity of 5000 to 50000 Pa · s.

  The reinforced flexible printed wiring board according to the present invention is obtained by the method of manufacturing the reinforced flexible printed wiring board.

  The thermosetting resin composition according to the present invention comprises a (meth) acrylic polymer, an epoxy resin having a melt viscosity of 0.1 Pa · s or less at 140 to 180 ° C., and an epoxy resin curing agent, and 120 The melt viscosity at 160 ° C. is 5000 to 50000 Pa · s.

  The thermosetting adhesive sheet according to the present invention comprises a (meth) acrylic polymer, an epoxy resin having a melt viscosity of 0.1 Pa · s or less at 140 to 180 ° C., and an epoxy resin curing agent, and 120 to 160 The thermosetting adhesive layer formed from the thermosetting resin composition whose melt viscosity in ° C is 5000-50000 Pa.s is formed on a substrate film.

  The present invention comprises a (meth) acrylic polymer, an epoxy resin having a melt viscosity at 140 to 180 ° C. equal to or less than a predetermined value, and an epoxy resin curing agent, and the melt viscosity at 120 to 160 ° C. has a predetermined value. By using the thermosetting resin composition, the moisture and the like in the vaporized connection base material can be easily removed from the thermosetting adhesive layer. Therefore, bubbles at the adhesion interface of the thermosetting adhesive layer can be suppressed.

Hereinafter, embodiments of the present invention will be described in detail in the following order. In the present specification, the (meth) acrylic polymer includes an acrylic polymer and a methacrylic polymer. In the present specification, the melt viscosity is a value measured with a cone plate viscometer.
1. 1. Thermosetting resin composition 2. Thermosetting adhesive sheet Manufacturing method of reinforced flexible printed wiring board Example

<1. Thermosetting resin composition>
The thermosetting resin composition according to the present embodiment contains a (meth) acrylic polymer, an epoxy resin having a melt viscosity of 0.1 Pa · s or less at 140 to 180 ° C., and an epoxy resin curing agent. The melt viscosity at 120 to 160 ° C. is 5000 to 50000 Pa · s.

  The thermosetting resin composition has a melt viscosity at 1,500 to 50000 Pa · s at 120 to 160 ° C., for example, via a thermosetting adhesive layer formed from the thermosetting resin composition, a flexible printed wiring At the time of thermal lamination of the plate and the connection base, or at the time of heat treatment after the thermal lamination, air bubbles at the adhesion interface of the thermosetting adhesive layer can be suppressed. It is preferable that melt viscosity in 120-160 degreeC of the thermosetting resin composition is 6000 Pa.s or more, and it is more preferable that it is 7000 Pa.s or more. Moreover, it is preferable that it is 45000 Pa.s or less, and, as for the upper limit of melt viscosity in 120-160 degreeC, it is more preferable that it is 40000 Pa.s or less. The thermosetting resin composition preferably has a melt viscosity at 140 ° C. of 5000 to 50000 Pa · s. Hereinafter, each component of the thermosetting resin composition will be described in detail.

[(Meth) acrylic polymer]
The (meth) acrylic polymer is a polymer of (meth) acrylic monomers. The polymerization method of the (meth) acrylic polymer is not particularly limited, and for example, pearl polymerization is preferably used from the viewpoint of obtaining a high molecular weight.

  Examples of (meth) acrylic monomers include butyl acrylate, 2-ethylhexyl acrylate, ethyl acrylate, nitrile acrylic acid, glycidyl methacrylate and the like. These (meth) acrylic monomers can be used singly or in combination of two or more.

  The (meth) acrylic polymer preferably has a glass transition temperature of -5 to 15 ° C. By satisfying such a condition, bubbles at the adhesion interface of the thermosetting adhesive layer can be more effectively suppressed.

The glass transition temperature of the (meth) acrylic polymer can be calculated by the following formula (1) (FOX formula).
1 / Tg = W1 / T1 + W2 / T2 +... Wn / Tn (1)
In the formula (1), W1, W2... Wn are mass fractions of respective monomers, and T1, T2... Tn are glass transition temperatures (K) of respective monomers.

[Epoxy resin]
The epoxy resin has a melt viscosity at 140 to 180 ° C. of 0.1 Pa · s or less. With such a configuration, for example, at the time of the above-described heat treatment, the flowability of the epoxy resin in the thermosetting adhesive layer is improved, so that air bubbles at the adhesive interface of the thermosetting adhesive layer can be suppressed.

  From the viewpoint of achieving suppression of the bubbles more effectively, the epoxy resin preferably has a melt viscosity of 0.1 Pa · s or less at 140 to 160 ° C., and a melt viscosity at 140 to 160 ° C. of 0. It is more preferable that the viscosity be less than 08 Pa · s, and it is further preferable that the melt viscosity at 150 ° C. be less than 0.08 Pa · s. The lower limit of the melt viscosity at 140 to 180 ° C. is preferably 0.01 Pa · s or more.

  The epoxy resin preferably has a softening point of 85 ° C. or lower. With such a configuration, the epoxy resin in the thermosetting adhesive layer is softened quickly, for example, at the time of the above-described thermal lamination and heat treatment, so that bubbles at the adhesive interface of the thermosetting adhesive layer are more effectively suppressed. be able to.

  Specific examples of the epoxy resin include, for example, dicyclopentadiene type epoxy resin, bisphenol type epoxy resin, naphthalene type epoxy resin, novolac phenol type epoxy resin, biphenyl type epoxy resin and the like, and the melt viscosity at 140 to 180 ° C. Can satisfy the condition of 0.1 Pa · s or less. In particular, dicyclopentadiene type epoxy resins and bisphenol type epoxy resins are preferable from the viewpoint of more effectively suppressing the air bubbles at the adhesive interface of the thermosetting adhesive layer.

  5 mass parts or more are preferable with respect to 100 mass parts of (meth) acrylic polymers, and, as for content of an epoxy resin, 10 mass parts or more are more preferable. Moreover, 30 mass parts or less are preferable with respect to 100 mass parts of (meth) acrylic polymers, and, as for the upper limit of content of an epoxy resin, 25 mass parts or less is more preferable. While setting it as such a range, while suppressing the bubble in the adhesion interface of a thermosetting adhesive layer more effectively, peeling strength can be improved more. An epoxy resin may be used individually by 1 type, and may use 2 or more types together. When using 2 or more types together, it is preferable that total amount satisfy | fills the said range.

[Epoxy resin curing agent]
As an epoxy resin curing agent, a phenol type curing agent, an amine type curing agent, an imidazole type curing agent, an acid anhydride type curing agent, an organic peroxide type curing agent, etc. can be used, and a phenol type curing agent and an amine type curing agent Agents are preferred.

  Examples of the phenol-based curing agent include phenol novolac, bisphenol A novolac, cresol novolac and the like, and phenol novolac is preferable. Specific examples of the phenolic curing agent include PHENOLITE TD-2131, TD-2106, TD-2093, TD-2091, TD-2090 (all manufactured by DIC Corporation) and the like.

  Use amine-based curing agents such as aromatic amines such as diaminodiphenylmethane and diaminodiphenylsulfone, aliphatic amines, imidazole derivatives, dicyandiamide, tetramethylguanidine, thiourea addition amines, and isomers and modified products thereof. Can do. Among these, diaminodiphenyl sulfone is preferable.

  Examples of the imidazole curing agent include 2-methylimidazole and 2-phenylimidazole.

  Examples of the acid anhydride curing agent include phthalic anhydride and maleic anhydride.

  Examples of the organic peroxide curing agent include rhoyl peroxide, butyl peroxide, benzyl peroxide, dilauroyl peroxide, dibutyl peroxide, benzyl peroxide, peroxydicarbonate, benzoyl peroxide, and the like.

  The content of the epoxy resin curing agent is preferably 1 to 30 parts by mass, and more preferably 5 to 20 parts by mass, with respect to 100 parts by mass of the (meth) acrylic polymer. By setting it as such a range, sclerosis | hardenability can be made more favorable. An epoxy resin hardening | curing agent may be used individually by 1 type, and may use 2 or more types together. When using 2 or more types together, it is preferable that total amount satisfy | fills the said range.

[Other additives]
The thermosetting resin composition may optionally contain other additives other than the above-described compounds, or may not substantially contain other additives. Other additives include conductive particles, heat conductive particles, film forming resins, acrylic rubber, monomers for dilution such as various acrylic monomers, fillers, softeners, colorants, flame retardants, thixotropic agents, Coupling agents and the like can be mentioned.

  As described above, since the thermosetting resin composition according to the present embodiment has a small tackiness, it is difficult to cause air bubbles to be caught during bonding, and dust is not easily attached. In addition, even if the tack is small, it exhibits excellent temporary adhesion properties to metals such as SUS, aluminum and gold, and has excellent workability. Therefore, it can be suitably used for applications in which the flexible printed wiring board and the connection base material are bonded together.

  A thermosetting resin composition can be prepared by mixing each component mentioned above uniformly by a conventional method. The thermosetting resin composition can be in the form of a paste, a film, a dispersed liquid, or the like. In particular, a thermosetting adhesive layer having a thermosetting adhesive layer formed from the above-mentioned thermosetting resin composition on a substrate film (release substrate) subjected to release treatment from the viewpoint of storage properties and handling properties at the time of use, etc. The form of an adhesive sheet is preferable.

<2. Thermosetting adhesive sheet>
In the thermosetting adhesive sheet according to the present embodiment, a thermosetting adhesive layer formed from the above-mentioned thermosetting resin composition is formed on a base film.

  The thermosetting adhesive sheet is, for example, coated with the above-mentioned thermosetting resin composition on a base film by a bar coater, a roll coater or the like so that the thickness after drying becomes 10 to 60 μm. It can be obtained by drying by the method.

  The base film can use the peeling base material in which the peeling process was carried out with silicone etc. as needed to base materials, such as a polyethylene terephthalate film and a polyimide film.

  The thermosetting adhesive sheet can be preferably applied, for example, in order to bond and fix a terminal portion of a flexible printed wiring board and a connection base for backing. In addition, since the thermosetting adhesive sheet and the connection substrate can be easily brought into close contact with each other by the heat lamination, the workability can be improved.

<3. Method of manufacturing reinforced flexible printed wiring board>
In the method of producing a reinforced flexible printed wiring board according to the present embodiment, the step of thermally laminating the flexible printed wiring board and the connection base material at a temperature of 120 to 160 ° C. via a thermosetting adhesive layer; Heat treating at a temperature of -180 ° C.

[Step of heat laminating]
In the heat laminating step, the flexible printed wiring board and the connection base material are heat laminated at a temperature of 120 to 160 ° C. via a thermosetting adhesive layer.

  The thermosetting adhesive layer uses the above-described thermosetting resin composition. That is, the thermosetting resin composition constituting the thermosetting adhesive layer exhibits fluidity at the time of heat lamination since it exhibits a melt viscosity of 5000 to 50000 Pa · s at the setting temperature at the time of heat lamination, that is, 120 to 160 ° C. Becomes better. Therefore, air bubbles can be easily removed from the thermosetting adhesive layer at the time of heat lamination, and air bubbles at the adhesive interface of the thermosetting adhesive layer can be suppressed.

  The flexible printed wiring board has, for example, a substrate on which a conductor pattern having a terminal portion coated with a plating film is formed on a base material. As the substrate, for example, a resin film can be used, and a polyimide film is preferable. The thickness of the substrate is usually about 12 to 25 μm.

  As the base material for connection, for example, a base material such as a polyimide film, a glass epoxy plate, or a metal plate can be used. The thickness of the connecting substrate is usually about 50 μm to 2 mm.

  The temperature for heat laminating is 120 to 160 ° C, preferably 130 to 150 ° C. By setting it as such a range, the bubble in the adhesion interface of a thermosetting contact bonding layer can be suppressed more effectively. The heat lamination can be performed, for example, using a heat laminating apparatus, and is preferably performed using a heat roll laminating apparatus. When using a hot roll laminator, the laminating speed is preferably 0.1 to 1.0 m / min. Moreover, it is preferable to set roll temperature to 120-160 degreeC.

  The following method is mentioned as a specific example of the process of heat laminating. First, a thermosetting adhesive sheet cut into a predetermined size is temporarily attached to a connection substrate, and the substrate film is removed from the thermosetting adhesive sheet to expose the thermosetting adhesive layer. Then, the terminal portion of the flexible printed wiring board is superimposed on the exposed thermosetting adhesive layer, and heat lamination is performed using a heat roll laminating apparatus.

[Step of heat treatment]
In the heat treatment step, the heat treatment temperature is 140 to 180 ° C, preferably 140 to 160 ° C. By setting it as such a range, the bubble in the adhesion interface of a thermosetting contact bonding layer can be suppressed more effectively. The heat treatment can be performed using, for example, an oven. The heat treatment time is usually preferably 60 minutes or more.

  In the heat treatment step, the epoxy resin in the thermosetting adhesive layer mentioned above has a set temperature at the time of heat treatment, that is, a melt viscosity at 140 to 180 ° C. of 0.1 Pa · s or less. The fluidity of the thermosetting resin composition constituting the adhesive layer is improved. Therefore, air bubbles can be easily removed from the thermosetting adhesive layer at the time of heat treatment, and air bubbles at the adhesive interface of the thermosetting adhesive layer can be suppressed.

  As described above, according to the method of manufacturing a reinforced flexible printed wiring board according to the present embodiment, a thermosetting adhesive layer is formed by using the thermosetting adhesive layer formed from the above-described thermosetting resin composition. Air bubbles at the bonding interface can be suppressed. Therefore, it is not necessary to have substantially other processes other than the heat laminating process and the heat treatment process described above. Specifically, it does not have a heat-pressing step (for example, a step of heat-pressurizing at a pressure of 0.5 MPa or more after the above-described heat-laminating step) or the like conventionally required for the purpose of suppressing air bubbles. May be. Moreover, the step of thermally laminating and the step of heat treatment described above can be performed under normal pressure, not under a pressurized atmosphere or a reduced pressure atmosphere. Therefore, it is possible to reduce the process load, the equipment investment, the workability, and the like.

  Further, the reinforced flexible printed wiring board obtained by the above-described method for producing a reinforced flexible printed wiring board has good peel strength and heat resistance because air bubbles at the adhesion interface of the thermosetting adhesive layer are suppressed.

  Examples of the present invention will be described below. In this example, a thermosetting resin composition containing a (meth) acrylic polymer, an epoxy resin and an epoxy resin curing agent was produced, and a thermosetting adhesive sheet was produced using this thermosetting resin composition. . And the reinforcement flexible printed wiring board (test pieces 1-3) for a test was produced using the thermosetting adhesive sheet, and it evaluated about the item of following (1)-(4). The present invention is not limited to these examples.

Example 1
[Preparation of Thermosetting Resin Composition]
100 parts by mass of a (meth) acrylic polymer having a glass transition temperature of −4 ° C. and an epoxy resin (melt viscosity at 150 ° C .: 0.03 Pa · s, trade name: HP-7200L, manufactured by DIC Corporation) 20 A thermosetting resin composition was prepared by mixing 20 parts by mass of an epoxy resin curing agent (trade name: PHENOLITE TD2131, manufactured by DIC Corporation) with a mass part. The melt viscosity at 140 ° C. of the obtained thermosetting resin composition was 7.65E + 03 Pa · s.

Example 2
100 parts by mass of (meth) acrylic polymer having a glass transition temperature of 13 ° C. and 10 parts by mass of epoxy resin (melt viscosity at 150 ° C .: 0.03 Pa · s, trade name: HP-7200 L, manufactured by DIC Corporation) Parts, 10 parts by mass of epoxy resin (melt viscosity at 150 ° C .: 0.01 Pa · s, trade name: YSLV-80XY, manufactured by Nippon Steel Sumikin Chemical Co., Ltd.), epoxy resin curing agent (trade name: PHENOLITE TD2131 , Manufactured by DIC Corporation) was mixed with 15 parts by mass to prepare a thermosetting resin composition. The melt viscosity at 140 ° C. of the obtained thermosetting resin composition was 3.34E + 04 Pa · s.

[Example 3]
100 parts by mass of (meth) acrylic polymer having a glass transition temperature of 13 ° C., and 15 parts of an epoxy resin (melt viscosity at 150 ° C .: 0.08 Pa · s, trade name: HP-4770, manufactured by DIC Corporation) Parts, 10 parts by mass of epoxy resin (melt viscosity at 150 ° C .: 0.01 Pa · s, trade name: YSLV-80XY, manufactured by Nippon Steel Sumikin Chemical Co., Ltd.), epoxy resin curing agent (4, 4′- A thermosetting resin composition was prepared by mixing 5 parts by mass of diaminodiphenylsulfone (4,4′-DDS). The melt viscosity at 140 ° C. of the obtained thermosetting resin composition was 2.54E + 04 Pa · s.

Comparative Example 1
100 parts by mass of (meth) acrylic polymer having a glass transition temperature of −4 ° C., and epoxy resin (melt viscosity at 150 ° C .: 0.75 Pa · s, trade name: N-775, manufactured by DIC Corporation) 20 The thermosetting resin composition was prepared by mixing a mass part and 15 mass parts of epoxy resin hardening agents (brand name: PHENOLITE TD2131, DIC Corporation make). The melt viscosity at 140 ° C. of the obtained thermosetting resin composition was 9.88E + 04 Pa · s.

Comparative Example 2
100 parts by weight of a (meth) acrylic polymer having a glass transition temperature of 13 ° C. and 20 parts by weight of an epoxy resin (melt viscosity at 150 ° C .: 0.4 Pa · s, trade name: HP-7200H, manufactured by DIC Corporation) The thermosetting resin composition was prepared by mixing 15 parts by mass with an epoxy resin curing agent (trade name: PHENOLITE TD2131, manufactured by DIC Corporation). The melt viscosity at 140 ° C. of the obtained thermosetting resin composition was 2.99 E + 04 Pa · s.

Comparative Example 3
100 parts by mass of (meth) acrylic polymer having a glass transition temperature of 23 ° C., and 20 parts by mass of epoxy resin (melt viscosity at 150 ° C .: 0.03 Pa · s, trade name: HP-7200 L, manufactured by DIC Corporation) A thermosetting resin composition was prepared by mixing 20 parts by mass of an epoxy resin curing agent (trade name: PHENOLITE TD2131, manufactured by DIC Corporation) and an epoxy resin curing agent. The melt viscosity at 140 ° C. of the obtained thermosetting resin composition was 1.21E + 05 Pa · s.

Comparative Example 4
100 parts by mass of (meth) acrylic polymer having a glass transition temperature of −10 ° C., and an epoxy resin (melt viscosity at 150 ° C .: 0.03 Pa · s, trade name: HP-7200 L, manufactured by DIC Corporation) 20 The thermosetting resin composition was prepared by mixing a mass part and 5 mass parts of epoxy resin hardeners (4,4'- diamino diphenyl sulfone (4,4'-DDS)). The melt viscosity at 140 ° C. of the obtained thermosetting resin composition was 3.54E + 03 Pa · s.

[Preparation of thermosetting adhesive sheet]
The thermosetting resin composition was applied to a polyethylene terephthalate film subjected to peeling treatment and dried in a drying oven at 50 to 130 ° C. to produce a thermosetting adhesive sheet having a thickness of 35 μm.

  Test pieces (reinforcing flexible printed wiring boards for test) 1 to 3 were produced using the thermosetting adhesive sheets obtained in Examples and Comparative Examples.

[Preparation of Specimen 1]
The thermosetting adhesive layer of the thermosetting adhesive sheet cut into a strip (5 cm × 10 cm) was temporarily attached with a polyimide film (Apical 175H, manufactured by Kaneka Corporation) having a thickness of 175 μm. Subsequently, the base film was removed from the thermosetting adhesive sheet to expose the thermosetting adhesive layer. A 50 μm thick polyimide film (Kapton 200H, manufactured by DuPont) of the same size is superimposed on the exposed thermosetting adhesive layer from above, and a roll laminator set at 140 ° C. and a speed of 0.3 m / min is used. Pasted together. Then, it was kept in an oven at 140 ° C. for 60 minutes. Thus, a test piece 1 was obtained.

[Preparation of Specimen 2]
A test piece 2 was obtained by the same method as the preparation of the test piece 1 except that the polyimide film having a thickness of 175 μm was changed to a SUS304 plate having a thickness of 0.5 mm in the preparation of the test piece 1.

[Preparation of Specimen 3]
A test piece 3 was obtained in the same manner as the test piece 1 except that the 175 μm thick polyimide film was changed to a 1 mm thick glass epoxy plate (FR 4) in the preparation of the test piece 1.

[(1) Presence of air bubbles in the thermosetting adhesive layer]
About each test piece 1, the presence or absence of the bubble in the interface of a polyimide film and a thermosetting contact bonding layer was observed visually. The case where almost no bubbles were observed and the heat resistance was not affected was evaluated as “◎”. The case where air bubbles could be confirmed but did not affect the heat resistance was evaluated as “◯”. The case where bubbles were observed and the heat resistance was affected was evaluated as “x”. The results are shown in Table 1.

[(2) Peel strength]
For each of the test pieces 1 to 3, a polyimide film having a thickness of 50 μm was subjected to a 90 ° peeling test at a peeling speed of 50 mm / min to measure the force required for peeling. The results are shown in Table 1.

[(3) Moisture absorption solder float heat resistance test]
Each of the test pieces 1 was floated on the liquid surface of a solder bath set at 288 ° C. for 10 seconds, and was visually observed whether the test piece 1 swelled or peeled off. The case where the appearance was not abnormal at all, or the case where a slight swelling was observed on the test piece 1 but there was no problem in practical use was evaluated as “o”. A case where swelling due to foaming was observed on the test piece 1 was evaluated as “x”. The results are shown in Table 1.

[(4) Reflow heat resistance test]
The test piece 1 was left for 96 hours in a wet heat oven at 140 ° C. and a relative humidity of 90%. Next, the test piece 1 immediately after the wet heat treatment is passed through a reflow furnace set at a top temperature of 260 ° C. for 30 seconds three times (total of 5 minutes), and the test piece 1 after the passage is swollen and there is no appearance abnormality such as peeling Was visually observed. The evaluation in the case where there was no abnormality in the appearance or in a case where a slight swelling was observed on the test piece 1 but there was no problem in practical use was evaluated as "○". The evaluation in the case where swelling due to foaming was observed on the test piece 1 was evaluated as “x”. The results are shown in Table 1.

  As in Examples 1 to 3, it contains (meth) acrylic polymer, an epoxy resin having a melt viscosity of 0.1 Pa · s or less at 140 to 180 ° C., and an epoxy resin curing agent, at 120 to 160 ° C. It has been found that when a thermosetting resin composition having a melt viscosity of 5000 to 50000 Pa · s is used, it is possible to suppress air bubbles at the adhesion interface of the thermosetting adhesive layer.

  In particular, when using a thermosetting resin composition containing an epoxy resin having a melt viscosity at 140 to 180 ° C. of less than 0.08 Pa · s as in Examples 1 and 2, adhesion of a thermosetting adhesive layer It was found that bubbles at the interface can be more effectively suppressed. Moreover, in Examples 1-3, it turned out that heat resistance and peeling strength are also favorable.

  On the other hand, when a thermosetting resin composition not containing an epoxy resin having a melt viscosity at 140 to 180 ° C. of 0.1 Pa · s or less is used as in Comparative Examples 1 and 2, the thermosetting adhesive layer It has been found that it is difficult to suppress bubbles at the bonding interface. Moreover, in Comparative Examples 1 and 2, it turned out that heat resistance is not favorable. Furthermore, in Comparative Examples 1 and 2, it turned out that the peeling strength is inferior compared with an Example.

Moreover, when the thermosetting resin composition whose melt viscosity in 120-160 degreeC does not satisfy 5000-50000 Pa.s is used like Comparative example 3 and 4, the bubble in the adhesion interface of a thermosetting adhesive layer is It proved to be difficult to suppress. In Comparative Examples 3 and 4, it was found that the heat resistance was not good. Furthermore, in Comparative Example 4, it was found that the peel strength was inferior to that of the Example.

Claims (12)

Thermally laminating the flexible printed wiring board and the connection base material at a temperature of 120 to 160 ° C. through a thermosetting adhesive layer, and heat treating at a temperature of 140 to 180 ° C.
The thermosetting adhesive layer contains a (meth) acrylic polymer, an epoxy resin having a melt viscosity of 0.1 Pa · s or less at 140 to 180 ° C., and an epoxy resin curing agent, and the 120 to 160 ° C. The manufacturing method of the reinforcement flexible printed wiring board which is formed from the thermosetting resin composition whose melt viscosity in above is 5000-50000 Pa.s.   The manufacturing method of the reinforced flexible printed wiring board of Claim 1 whose glass transition temperature of said (meth) acrylic polymer is -5-15 degreeC.   The manufacturing method of the reinforced flexible printed wiring board of Claim 1 or 2 whose softening point of the said epoxy resin is 85 degrees C or less.   The method for producing a reinforced flexible printed wiring board according to any one of claims 1 to 3, wherein the epoxy resin contains at least one of dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, and bisphenol type epoxy resin. .   The content of the said epoxy resin in the said thermosetting resin composition is 5-30 mass parts with respect to 100 mass parts of said (meth) acrylic polymers, The said any one of Claims 1-4 Manufacturing method of a reinforced flexible printed wiring board.   The method for producing a reinforced flexible printed wiring board according to any one of claims 1 to 5, wherein the epoxy resin has a melt viscosity at 150 ° C of less than 0.08 Pa · s.   The method for producing a reinforced flexible printed wiring board according to any one of claims 1 to 6, wherein the thermosetting resin composition has a melt viscosity at 1400C of 5000 to 50000 Pa · s.   The manufacturing method of the reinforcement flexible printed wiring board of any one of Claims 1-7 which performs the said heat lamination using a heat roll laminating apparatus.   The manufacturing method of the reinforcement flexible printed wiring board of any one of Claims 1-8 which do not have the process of heat-pressing by the pressure of 0.5 Mpa or more after the process of carrying out the said heat lamination.   The method for producing a reinforced flexible printed wiring board according to any one of claims 1 to 9, wherein the step of thermally laminating and the step of thermally treating are performed under normal pressure. (Meth) acrylic polymer having a glass transition temperature of -5 to 15 ° C, an epoxy resin having a melt viscosity at 140 to 180 ° C of 0.1 Pa · s or less, and an epoxy resin curing agent, 120 to 160 A thermosetting resin composition having a melt viscosity of 5000 to 50000 Pa · s at ° C. (Meth) acrylic polymer having a glass transition temperature of -5 to 15 ° C, an epoxy resin having a melt viscosity at 140 to 180 ° C of 0.1 Pa · s or less, and an epoxy resin curing agent, 120 to 160 The thermosetting adhesive sheet in which the thermosetting adhesive layer formed from the thermosetting resin composition whose melt viscosity in 5 degreeC is 5000-50000 Pa.s is formed on the base film.