JP2006232951A - Method for producing prepreg - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for reducing the amount of remaining voids in a prepreg by reducing the lack of impregnation of a resin varnish in the prepreg to suppress the occurrence of migration of CAF (conductive anodic filaments) or the like in a printed wiring board manufactured by the prepreg. <P>SOLUTION: The method comprises a process comprising passing a long substrate 1 sequentially a tension-applying means 4 which applies predetermined tension to a long substrate 1 by applying stress in a direction orthogonal to the transfer direction of the substrate 1 while conveying the substrate 1 in its length direction continuously, and a resin-impregnating means 5 for immersing the substrate 1 in a resin varnish 2. The tension-applying means 4 comprises a tension-applying roll 7 for pressing the surface of the substrate 1 with a predetermined load by driving force transmitted from a torque motor. Control of the torque motor applies desired tension to prevent the occurrence of the slack of the substrate 1. Thus, the occurrence of fine voids between the fibers composing the substrate 1 is prevented to suppress the lack of impregnation of the resin varnish 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a prepreg used for manufacturing a printed wiring board.

  Conventionally, a laminated board used in the production of a printed wiring board, for example, impregnates a base material such as a glass cloth with a thermosetting resin varnish such as an epoxy resin, and then prepares a prepreg by heat drying and semi-curing, The prepreg is manufactured by stacking a required number of sheets and, if necessary, placing a metal foil such as a copper foil on one side or both sides and laminating and heating and pressing to form. In addition, the multilayer laminate is formed by etching the metal foil on the surface of the metal foil-clad laminate obtained by the above method to form a circuit, and then, on the front and back of the laminate on which the circuit is formed, Are laminated by placing a metal foil on one side or both sides as necessary, and forming by heating and pressing.

  Since the resin varnish generally has a high viscosity, the resin varnish is not sufficiently impregnated into the inside of the base material, and bubbles may remain in the prepreg. Such residual bubbles cause migration and cause insulation failure of the printed wiring board.

For this reason, in order to suppress the occurrence of non-impregnation of the resin varnish 2 in the prepreg, various studies have been made heretofore. A method has been proposed in which the resin varnish is further impregnated with the base material in a state in which the base material contains the solvent and the like after being removed (see Patent Document 1).
Japanese Patent Laid-Open No. 9-227699

  Along with the recent improvement in wiring density in printed wiring boards, the distance between walls of through holes and via holes in printed wiring boards has been reduced from about 500 μm to about 250 μm. Migration (Conductive Anodical Filaments) is more likely to occur. For this reason, it is necessary to further reduce the remaining amount of bubbles in the prepreg and further suppress the occurrence of migration, but the conventional method as described above has a limit in suppressing the unimpregnation of the resin varnish, A technique for further reducing the remaining amount of bubbles has been demanded.

  The present invention has been made in view of the above points, and in the printed wiring board manufactured with this prepreg, the amount of remaining bubbles in the prepreg is reduced by reducing the unimpregnation of the resin varnish in the prepreg. An object of the present invention is to provide a method for producing a prepreg capable of suppressing the occurrence of migration such as CAF (Conductive Anodical Filaments).

  The present invention relates to a method for producing a prepreg 3 in which a base material 1 is impregnated with a resin varnish 2 and then dried, while the long base material 1 is continuously transported in the longitudinal direction, Including a step of sequentially passing tension applying means 4 for applying a constant tension to the base material 1 by applying stress in a direction orthogonal to the resin impregnating means 5 for immersing the base material 1 in the resin varnish 2; The tension applying means 4 includes a tension applying roll 7 that presses the surface of the substrate 1 with a constant load by a driving force transmitted from a torque motor. If it does in this way, desired tension can be easily given to substrate 1 immersed in resin varnish 2 by resin impregnation means 5 by control of a torque motor, and tension is given to substrate 1 in this way. By doing so, it is possible to prevent the occurrence of slack in the base material 1 and prevent the formation of fine voids between the fibers constituting the base material 1. For this reason, the base material 1 is impregnated with the resin varnish 2. The occurrence of unimpregnation in the case can be suppressed.

In the tension applying means 4, it is preferable to apply a tension of 11 to 21 N / m ^{2 to} the substrate 1. In such a range, the looseness of the base material 1 can be sufficiently suppressed, and the non-impregnation of the resin varnish 2 in the base material 1 can be further suppressed.

  In the method for producing the prepreg 3, the primary impregnation means 8 for impregnating the base material 1 by injecting the primary impregnation liquid 6 made of a solvent or a resin varnish before the base material 1 passes through the resin impregnation means 5. It is also preferable to allow the substrate 1 to pass through. In this way, the resin impregnating means 5 can be impregnated with the primary impregnating liquid 6 in the state where the primary impregnating means 6 has impregnated the details of the base material 1 with the primary impregnating means 8 so that the resin varnish 2 can be impregnated. In addition, the non-impregnation can be further suppressed, and even when the primary impregnation means 8 is impregnated with the primary impregnation liquid 6, the base material 1 is under tension, so that the non-impregnation is further suppressed. Is something that can be done.

  In addition, it is also preferable that a load is applied to the surface of the base material 1 after passing through the primary impregnation means 8 as described above and before passing through the resin impregnation means 5 with a pressing roll 9. In this way, the primary impregnating liquid 6 impregnated in the base material 1 by the primary impregnation means 8 can be further pushed into the base material 1 by the pushing roll 9, and the occurrence of non-impregnation can be further suppressed. It is.

  According to the present invention, since non-impregnation of the resin varnish in the base material in the prepreg can be suppressed, when a printed wiring board is produced with this prepreg, bubbles in the insulating layer formed with the prepreg Residue is reduced, thereby preventing the occurrence of migration such as CAF (Conductive Anodical Filaments), that is, a printed wiring board having excellent migration resistance can be obtained.

  Hereinafter, the present invention will be described based on the best mode for carrying out the invention.

  As the base material 1, an appropriate material used for the production of the prepreg 3 can be adopted, and it is not particularly limited. For example, various glass cloths such as roving cloth, cloth, chopped mat, and surfacing mat. , Asbestos cloth, metal fiber cloth, other synthetic or natural inorganic fiber cloth; woven or non-woven fabric obtained from liquid crystal fiber such as wholly aromatic polyamide fiber, wholly aromatic polyester fiber, polybenzozar fiber; polyvinyl alcohol fiber, Woven or non-woven fabrics obtained from synthetic fibers such as polyester fibers and acrylic fibers; natural fiber woven fabrics such as cotton cloth, linen and felt; carbon fiber cloth; natural cellulosic materials such as kraft paper, cotton paper and paper-glass mixed paper Cloth etc. can be mentioned.

  Further, as the resin varnish 2, an appropriate thermosetting resin varnish 2 used for manufacturing the prepreg 3 can be used. For example, it is prepared by blending and mixing an epoxy resin, a curing agent, a curing accelerator, a solvent and the like. It has been done. In addition, as the thermosetting resin varnish 2, a varnish containing various thermosetting resins such as a polyimide resin, a polyester resin, and a phenol resin can be used in addition to the epoxy resin.

  FIG. 1 shows an example of steps for carrying out the present invention. As the substrate 1, a long one is used, and the resin varnish 2 is impregnated while the substrate 1 is continuously conveyed along the longitudinal direction from a payoff reel (not shown) or the like.

  A tension applying unit 4 and a resin impregnating unit 5 are provided in this order in the conveyance path of the substrate 1.

  The tension applying means 4 applies a constant tension to the base material 1 by applying a stress in a direction orthogonal to the transport direction to the base material 1, and the surface of the base material 1 is driven by a driving force transmitted from a torque motor. Is provided with a tension imparting roll 7 that presses with a constant load.

  In the tension applying means 4 shown in the figure, a rope body 11 composed of a chain, a belt or the like is hung between two pulleys 10 arranged vertically, and a tension applying roll 7 which can be moved up and down on the rope body 11. It is linked to. A torque motor that applies a predetermined torque to the pulley 10a is connected to at least one of the two pulleys 10a. At this time, the stress due to the torque applied to the pulley 10a by the torque motor is transmitted to the tension applying roll 7 via the strip body 11, and a constant urging force toward the tension applying roll 7 toward the surface of the substrate 1 in the transport path. As a result, the tension applying roll 7 presses the surface of the base material 1 with a constant load to apply a constant tension to the base material 1. Here, in the example shown in the figure, the tension applying roll 7 is arranged above the conveying path of the base material 1 so as to be in contact with the upper surface of the base material 1, and in this state, the tension applying roll 7 is fixed downward toward the tension applying roll 7. The torque motor is operated so that the urging force is applied, and the upper surface of the substrate 1 is pressed with a constant load.

  A plurality of transport rolls 12 are arranged on the downstream side of the tension applying means 4 in the transport path of the base material 1, and the base material 1 is transported while being supported by the transport rolls 12. In the illustrated example, one of the transport rolls 12 on the downstream side of the tension applying unit 4 is provided with a tension measuring unit such as a load cell for measuring the tension applied to the substrate 1. It is formed as a tension measuring roll 13. At this time, by controlling the torque motor of the tension applying means 4 based on the tension value measured by the tension measuring roll 13, a predetermined constant tension is applied to the substrate 1. be able to.

  A resin impregnation means 5 for immersing the base material 1 in the resin varnish 2 is provided further downstream of the transport path of the base material 1. The resin impregnation means 5 in the illustrated example is configured by disposing a dip roll 15 in a container 14 in which the resin varnish 2 is stored, and the base material 1 introduced into the container 14 is the dip roll 15. It is supported by and pulled out upward. In addition, a pair of squeeze rolls 16, 16 are disposed above the container 14, and the base material 1 drawn upward passes between the squeeze rolls 16, 16 and the excess resin varnish 2 is squeezed. Thus, the resin impregnation amount is adjusted.

  Above the squeeze rolls 16, 16, an inverted U-shaped conveyance path is formed by the plurality of conveyance rolls 12, and a heating and drying furnace 17 is disposed in this portion. Thereby, after the base material 1 which passed the squeeze rolls 16 and 16 is introduce | transduced in the heating-drying furnace 17, and it heat-drys while conveying in reverse U shape, it is pulled out below.

  On the downstream side of the heating and drying furnace 17, the base material 1 is supported by the transport roll 12 and pulled out in the lateral direction, and is pressed above the transport path of the base material 1 so as to be in contact with the upper surface of the base material 1. A roll 18 is provided. The pressing roll 18 presses a load toward the upper surface of the substrate 1.

When the prepreg 3 is produced by the above-described process, the substrate 1 is first given a constant tension by the pressing force of the tension applying roll 7 when passing through the tension applying means 4. This tension is in an appropriate range, but is preferably in the range of 11 to 21 N / m ² . If the tension applied to the substrate 1 is too small, the fibers constituting the substrate 1 may not be sufficiently slackened, and if the tension is excessive, the substrate 1 may tear off, There is a possibility that the substrate 1 is excessively bent.

  Next, the base material 1 is immersed in the resin varnish 2 in the resin impregnation means 5 in a state where the constant tension as described above is applied, and the resin varnish 2 is impregnated. At this time, since a constant tension is applied to the base material 1 as described above, loosening of the fibers constituting the base material 1 is reduced. Here, if the fibers constituting the base material 1 are slack, the fine gaps between the fibers in the base material 1 increase, which is sufficient for the above-described gaps when the resin varnish 2 is impregnated. It is difficult to infiltrate the resin varnish 2 into the base material, but if tension is applied to the base material 1 as described above, the slackness of the fibers constituting the base material 1 is reduced. Therefore, the occurrence of non-impregnation when the base material 1 is impregnated with the resin varnish 2 can be suppressed. The immersion time of the base material 1 in the resin impregnation means 5 is appropriately adjusted so that the base material 1 is sufficiently impregnated with the resin varnish 2, but is preferably in the range of 5 to 10 seconds.

  Next, when the base material 1 passes through the heating and drying furnace 17, the resin varnish 2 impregnated in the base material 1 becomes a semi-cured state (B stage state), and the prepreg 3 is formed. Next, the substrate 1 (prepreg 3) is subjected to pressing by the pressing roll 18, and at this time, when the prepreg 3 has irregularities formed on the surface due to formation of a resin pool during heating and drying, the pressing The surface is smoothed by pressing with the roll 18. The prepreg 3 formed in this way is further conveyed downstream in the conveyance path, and is cut into a single sheet by a cutting means such as a shear cutter, if necessary.

  With such a prepreg 3, a laminated board and a printed wiring board can be produced.

  For example, by stacking a single prepreg 3 or a plurality of prepregs 3 with a metal foil such as a copper foil disposed on both sides thereof, the laminated plate is integrated by heating and pressing. Can be produced.

  And a printed wiring board can be obtained by performing wiring processing and via-hole processing by an additive method, a subtractive method, etc. with respect to the laminated board obtained in this way. Moreover, a multilayer printed wiring board can also be formed by laminating | stacking and forming an insulating layer and a conductor layer by the buildup method etc. on the outer surface of such a printed wiring board.

  In the printed wiring board obtained in this way, since the residual bubbles in the insulating layer formed by the prepreg 3 is reduced, the occurrence of migration such as CAF (Conductive Anodical Filaments) can be prevented. That is, a printed wiring board excellent in migration resistance can be obtained.

  FIG. 2 shows another example of the process for carrying out the present invention. In the structure shown in FIG. 1, a primary impregnation means 8 is added.

  The primary impregnation means 8 is provided on the upstream side of the resin impregnation means 5. In the illustrated example, the primary impregnation means 8 is provided on the downstream side of the tension measuring means between the tension applying means 4 and the resin impregnation means 5.

  The primary impregnation means 8 is for impregnating the base material 1 with a primary impregnation liquid 6 made of a solvent or a resin varnish before the base material 1 passes through the resin impregnation means 5. Then, the injection nozzle 19 for injecting the primary impregnation liquid 6 toward the upper surface of the base material 1 is provided.

  Here, as the primary impregnation means 8, in addition to the above-described primary impregnation liquid 6 sprayed, the base 1 is impregnated with the primary impregnation liquid 6 by an appropriate means such as shower, float, single-side coating, etc. Although it is possible to provide the primary impregnating liquid 6 as described above, the impregnating property of the primary impregnating liquid 6 with respect to the substrate 1 can be enhanced by the injection from above.

  When the primary impregnation means 8 is impregnated with a solvent as the primary impregnation liquid 6, an appropriate solvent used for manufacturing the prepreg 3 can be used as the solvent, but the resin impregnation means 5 impregnates. The same solvent as that contained in the resin varnish 2 is preferably used.

  In the case of impregnating the resin varnish as the primary impregnation liquid 6 in the primary impregnation means 8, an appropriate resin varnish used for manufacturing the prepreg 3 can be used. For example, the resin impregnation means 5 The resin varnish having the same composition as the resin varnish 2 to be impregnated with can be used, and this resin varnish is less viscous than the resin varnish 2 used in the resin impregnation means 5 by adjusting the amount of the solvent. By doing so, it is preferable to improve the impregnation property to the base material 1.

  The injection amount of the primary impregnating liquid 6 in the primary impregnation means 8 is appropriately adjusted, but is preferably in the range of 2 to 10 L / min.

  Moreover, in the example of illustration, in the injection position of the primary impregnation liquid 6 by the primary impregnation means 8, between the two conveyance rolls 12 (upper position conveyance rolls 20 and 20), the conveyance position is lower than the conveyance roll 12. A roll 12 (lower position transport roll 21) is disposed, and in these three transport rolls 20, 21, 20, the base material 1 is placed on the upper surface side of one upper position transport roll 20, the lower surface side of the lower position transport roll 21, The base material 1 is transported in a substantially V-shaped or substantially U-shaped transport path by sequentially hanging and supporting on the upper surface side of the other upper position transport roll 20. Then, the primary impregnating liquid 6 is jetted toward the upper surface of the base material 1 that is substantially V-shaped or substantially U-shaped between the two upper position transport rollers 20 and 20. In this way, the primary impregnating liquid 6 sprayed toward the base material 1 is impregnated in the base material 1, and the material not impregnated in the base material 1 flows down along the surface of the base material 1. As a result, the primary primary impregnating liquid 6 is prevented from adhering to the base material 1.

  Other configurations are the same as those shown in FIG.

When the prepreg 3 is produced by the above-described process, the substrate 1 is first given a constant tension by the pressing force of the tension applying roll 7 when passing through the tension applying means 4. This tension is in an appropriate range, but is preferably in the range of 11 to 21 N / m ² .

  Next, the base material 1 is impregnated with the primary impregnation liquid 6 in the primary impregnation means 8 in a state in which a constant tension as described above is applied. At this time, by impregnating the primary impregnating liquid 6 having a lower viscosity than the resin varnish 2 in the resin impregnating means 5, it is possible to easily impregnate the details of the base material 1, thereby further suppressing the occurrence of non-impregnation. The Rukoto. Further, since the substrate 1 is applied with a constant tension as described above, the slackness of the fibers constituting the substrate 1 is reduced and the fine gaps between the fibers are reduced. The occurrence of non-impregnation of the primary impregnation liquid 6 is further suppressed.

  Next, the base material 1 is immersed in the resin varnish 2 in the resin impregnation means 5 in a state where a certain tension is applied. At this time, the primary impregnation liquid 6 impregnated in the primary impregnation means 8 is replaced with the resin varnish 2 in the resin impregnation means 5, and the resin varnish 2 is impregnated to the details of the substrate 1. Further, even when the resin varnish 2 is impregnated by the resin impregnation means 5, since the substrate 1 is applied with a constant tension as described above, the slackness of the fibers constituting the substrate 1 is reduced. Fine voids between the cage fibers are reduced, so that the occurrence of non-impregnation of the resin varnish 2 in the substrate 1 is further suppressed.

  Next, similarly to the embodiment shown in FIG. 1, the base material 1 is cut into a sheet by a cutting means such as a shear cutter after passing through the heating and drying furnace 17 and the pressing roll 18.

  Using the prepreg 3 thus obtained, a laminated board or a printed wiring board can be produced in the same manner as in the embodiment shown in FIG.

  In the printed wiring board obtained in this way, the remaining of bubbles in the insulating layer formed by the prepreg 3 is further reduced, thereby further preventing the occurrence of migration such as CAF (Conductive Anodic Filaments). In other words, a printed wiring board having excellent migration resistance can be obtained.

  FIG. 3 shows still another example of the process for carrying out the present invention. In the configuration shown in FIG. 2, a pushing roll 9 is added.

  The pressing roll applies a load to the surface of the base material 1 after passing through the primary impregnation means 8 and before passing through the resin impregnation means 5, and in the illustrated example, the two pressing rolls 9, 9, the load is sequentially applied to the one surface side and the other surface side of the substrate 1 respectively. The push roll 9 may be provided with a free rotating roll that is rotated by frictional force with the base material 1 when the base material 1 is transported, and is driven to rotate and drive the base material 1 with a driving force for transport. A roll may be provided.

  The pushing roll 9 is formed so as to bend the conveying path of the base material 1 by hanging and supporting the base material 1. In the illustrated example, the pushing roll 9 disposed on the upstream side of the base material 1 The conveyance path of the base material 1 is bent upward by hanging and supporting the upper surface, and the push roll 9 disposed on the downstream side is disposed at a position higher than the push roll 9 on the upstream side. The conveying path of the base material 1 is bent downward by hanging and supporting the lower surface of the material 1. By disposing the pushing roll 9 in this way, a load is applied to the one surface and the other surface of the base material 1 by the pushing roll 9 sequentially. The load applied to the base material 1 by the pushing roll 9 can be adjusted as appropriate by changing the position of the pushing roll 9 or the like, but is preferably in the range of 49 to 147N.

  Other configurations are the same as those shown in FIG.

When the prepreg 3 is produced by the above-described process, the substrate 1 is first given a constant tension by the pressing force of the tension applying roll 7 when passing through the tension applying means 4. This tension is in an appropriate range, but is preferably in the range of 11 to 21 N / m ² .

  Next, the base material 1 is impregnated with the primary impregnation liquid 6 in the primary impregnation means 8 in a state in which a constant tension as described above is applied. At this time, in the same manner as shown in FIG. 2, the occurrence of non-impregnation of the primary impregnating liquid 6 in the substrate 1 is suppressed.

  Next, the substrate 1 passes through the two pressing rolls 9, so that a load is sequentially applied from the respective pressing rolls 9 to the one surface side and the lower surface side. As a result, the primary impregnating liquid 6 is further pushed into the base material 1, and the occurrence of non-impregnation of the primary impregnating liquid 6 in the base material 1 is further suppressed.

  Next, the base material 1 is immersed in the resin varnish 2 in the resin impregnation means 5 in a state where a certain tension is applied. At this time, as in the case shown in FIG. 2, the primary impregnating liquid 6 impregnated in the primary impregnation means 8 is replaced with the resin varnish 2 in the resin impregnation means 5, and the resin varnish 2 reaches the details of the substrate 1. Although impregnated, since the occurrence of non-impregnation of the primary impregnating liquid 6 in the base material 1 is further suppressed in advance by the pushing roll 9 as described above, the resin varnish 2 that is impregnated by replacing these is impregnated. The occurrence of unimpregnation is further suppressed.

  Next, the substrate 1 passes through the heating and drying furnace 17 and the pressing roll 18 as in the above-described embodiments, and is then cut into sheets by a cutting means such as a shear cutter as necessary.

  Using the prepreg 3 thus obtained, a laminated board and a printed wiring board can be produced in the same manner as in the above embodiments.

  In the printed wiring board obtained in this way, the residual of bubbles in the insulating layer formed by the prepreg 3 is further reduced as compared with the embodiment shown in FIG. 2, and CAF (Conductive Anodic) is obtained. The occurrence of migration such as Films) can be further prevented, that is, a printed wiring board having further excellent migration resistance can be obtained.

Example 1
The prepreg 3 was produced using the equipment having the configuration shown in FIG.

  At this time, as the substrate 1, a long glass cloth having a thickness of 0.1 mm, a number of warp yarns of 59/25 mm, and a number of warp yarns of 57/25 mm was used.

  Moreover, as the resin varnish 2 impregnated in the base material 1 in the resin impregnation means 5, an FR-4 type epoxy resin composition having a viscosity of 100 cps was used, and the immersion time of the base material 1 in the resin impregnation means 5 was 7 seconds. .

In the tension applying means 4, the torque motor was operated so as to apply a tension of 13.7 N / m ^{2 to} the substrate 1.

  The heating conditions in the heating and drying furnace 17 were 180 ° C. and 4 minutes.

  Six sheets of prepregs 3 obtained by such a process are stacked, and further, 18 μm thick copper foil is stacked on both sides, and then heat and pressure molding is performed at 180 ° C. and 4 MPa for 90 minutes, molding and integration are performed on both sides. A copper clad laminate was prepared.

  The double-sided copper clad laminate thus obtained was 121 ° C., R.P. H. When exposed to 100% condition and observed the presence or absence of peeling between the insulating layer and the copper foil every hour, peeling occurred in 48 hours.

(Example 2)
The prepreg 3 was produced using equipment having the configuration shown in FIG.

At this time, in the tension applying means 4, the torque motor was operated so as to apply a tension of 16 N / m ^{2 to} the substrate 1.

  As the primary impregnation liquid 6 in the primary impregnation means 8, an FR-4 type epoxy resin composition having a viscosity of 80 cps was used, and the injection amount was 7 L / min.

  Other conditions were the same as in Example 1.

  Using the prepreg 3 obtained in such a process, a double-sided copper-clad laminate was prepared in the same manner as in Example 1. H. When it was exposed to 100% condition and the presence or absence of peeling between the insulating layer and the copper foil was observed every hour, peeling occurred in 96 hours.

(Example 3)
The prepreg 3 was produced using equipment having the configuration shown in FIG.

  At this time, the load to the base material 1 by the two pressing rolls 9 was set to 98 N, respectively.

  Other conditions were the same as in Example 2.

  Using the prepreg 3 obtained in such a process, a double-sided copper-clad laminate was prepared in the same manner as in Example 1. H. When it was exposed to 100% condition and the presence or absence of peeling between the insulating layer and the copper foil was observed every hour, peeling occurred in 168 hours.

(Comparative Example 1)
A prepreg 3 was produced using equipment having the configuration shown in FIG. 1 except that the tension applying means 4 was not provided as shown in FIG.

At this time, the tension measured by the tension measuring roll 13 was 9.2 N / m ² .

  Other conditions were the same as in Example 1.

  Using the prepreg 3 obtained in such a process, a double-sided copper-clad laminate was prepared in the same manner as in Example 1. H. When exposed to 100% condition and observed the presence or absence of peeling between the insulating layer and the copper foil every hour, peeling occurred in 24 hours.

(Evaluation)
When the double-sided copper-clad laminate is exposed to a high-temperature and high-humidity atmosphere as described above, separation occurs between the insulating layer and the copper foil because the air present in the voids in the insulating layer of this double-sided copper-clad laminate It is considered that water or water floats at the interface between the insulating layer and the copper foil.

  Therefore, the double-sided copper-clad laminates obtained in Examples 1 to 3 did not peel for a longer time than the case of Comparative Example 1 when exposed to a high-temperature and high-humidity atmosphere, so the double-sided copper obtained in Comparative Example 1 It can be evaluated that the void amount in the insulating layer is reduced as compared with the tension laminate.

  Further, in Examples 1 to 3, since the time during which separation does not occur sequentially becomes longer, the amount of voids in the insulating layer is reduced in the case of Example 2 than in the case of Example 1, and further implemented. In Example 3, it can be evaluated that the void amount is further reduced.

It is the schematic which shows the manufacturing process of the prepreg in an example of Embodiment of this invention, and Example 1. FIG. It is the schematic which shows the manufacturing process of the prepreg in the other example of embodiment of this invention, and Example 2. FIG. It is the schematic which shows the manufacturing process of the prepreg in the further of embodiment of this invention, and Example 3. FIG. 5 is a schematic view showing a manufacturing process of a prepreg 3 in Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Resin varnish 3 Prepreg 4 Tension applying means 5 Resin impregnating means 6 Primary impregnating liquid 7 Tension applying roll 8 Primary impregnating means 9 Pushing roll

Claims (4)

  In a method for producing a prepreg that is impregnated with a resin varnish and then dried, by applying a stress in a direction perpendicular to the conveyance direction to the substrate while continuously conveying the long substrate in the longitudinal direction Including a step of sequentially passing tension applying means for applying a constant tension to the base material and resin impregnation means for immersing the base material in a resin varnish, wherein the tension applying means is a driving force transmitted from a torque motor. A method for producing a prepreg comprising a tension applying roll that presses the surface of a substrate with a constant load. ^2. The method for producing a prepreg according to claim 1, wherein the tension applying means applies a tension of 11 to 21 N / m ² to the base material.   The base material passes through a primary impregnation means for impregnating the base material by injecting a primary impregnation liquid comprising a solvent or a resin varnish before the base material passes through the resin impregnation means. The manufacturing method of the prepreg of 1 or 2. 4. The method for producing a prepreg according to claim 3, wherein a load is applied to the surface of the base material after passing through the primary impregnation means and before passing through the resin impregnation means with a pressing roll.

Images