JP2017069294A - Manufacturing method of prepreg for printed wiring board and manufacturing equipment of prepreg for printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of prepreg for printed wiring board, and manufacturing equipment of prepreg for printed wiring board capable of efficiently producing a thin prepreg by applying a resin liquid to a base material while eliminating or reducing unapplied area in a plane applied with the resin liquid.SOLUTION: The manufacturing method of a prepreg for printed wiring board in which a long base material 3 is transported in a longitudinal direction, and resin liquid 13 is dried after being applied to the base material 3. The manufacturing method further includes a preparation step before applying the resin liquid 13 in which the base material is impregnated with a solvent.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a prepreg for a printed wiring board and an apparatus for manufacturing a prepreg for a printed wiring board.

  In recent years, as electronic components themselves have become denser, smaller, and thinner, the printed wiring board used for them has become thinner, and the prepreg used for printed wiring boards is also strongly demanded to be thinner. It has become to.

  Conventionally, a dip squeeze method or the like is known as a method for producing a prepreg for a printed wiring board. In this dip squeeze method, the substrate surface is immersed in a resin solution in which a resin for forming an insulating material is dissolved, impregnated with the resin solution, and then passed between squeeze rolls. The excess resin film adhering to the surface is scraped off, and the thickness of the resin film of the prepreg is adjusted to manufacture. However, in this method, it is difficult to control the resin thickness on the front and back of the prepreg. Therefore, a method of controlling the resin thickness of the front and back surfaces of the prepreg and applying a resin solution from the front and back surfaces of the base material with a die coater has come out.

  In Patent Document 1, the coating tip portions of two die coaters are arranged opposite to both sides of the substrate with respect to the substrate having a thickness of more than 50 μm, and both sides of the substrate are individually and simultaneously discharged pressure. A method of coating a resin solution over the same time is disclosed. Furthermore, by controlling the angle of inclination of the discharge direction of the two coating tips from the surface perpendicular to the substrate transport path, and simultaneously applying to both surfaces of the substrate, the bubbles are removed and the resin impregnation is achieved. It is possible to increase.

Japanese Patent Laid-Open No. 2004-290771

  However, for example, in order to produce a thin prepreg having a thickness of 20 μm or less, it is necessary to select a thin substrate having a thickness of 12 μm or less or to apply a small amount of resin liquid on both surfaces of the substrate. is there.

  The conventional dip squeeze method and the method of applying a resin liquid by simultaneously applying a discharge pressure with a die facing both sides of the base material of Patent Document 1 are applied via a resin liquid while applying tension to the base material in the traveling direction. Since pressure is simultaneously applied to both surfaces of the substrate, there is a concern that if the substrate is thin, the substrate is easily cut and the productivity is deteriorated.

  Moreover, when the base material is, for example, a fiber cloth woven with fiber yarns and the thickness of the thin base material is used as described above, the base material itself is reduced in rigidity, thereby reducing the rigidity of the base material itself.

  Furthermore, when the substrate is conveyed and applied while applying tensile tension in the longitudinal direction of the long thin substrate, the Poisson's ratio is compressed in the width direction of the substrate, so that the substrate surface Tends to form locally uneven lines in the longitudinal direction of the base material, and the surface of the base material becomes more non-smooth at that portion.

In particular, in the fiber cloth woven with the above-described fiber yarn, uneven lines are easily formed at a weakly woven portion in the substrate surface.

  Therefore, when applying the resin liquid to both sides of a thin substrate, if it is applied with a small amount of resin due to thickness restrictions, uncoated parts are likely to occur in non-smooth places due to uneven lines on the surface of the substrate. There was a problem that the productivity of the prepreg was lowered due to the failure at the part.

  Therefore, unlike the conventional resin liquid impregnation property that prevents bubbles from being contained in the base material, in particular, in the resin liquid coating on the thin base material, the local non-surface property that can be formed on the thin base material surface. It was necessary to improve the coating property to a smooth part.

  The present invention has been made in view of the above points. The method for producing a prepreg for a printed wiring board and a prepreg for a printed wiring board with improved productivity of resin coating on a base material and higher productivity than before. An object of the present invention is to provide a manufacturing apparatus.

  According to the method for manufacturing a prepreg for a printed wiring board according to the present invention, a printed wiring board including a step of drying a long base material after transporting the base material in the longitudinal direction, coating a resin liquid on the base material, and the like. In the method for producing a prepreg for a plate, a solvent impregnation step of impregnating the base material with a solvent is provided in a step before applying the resin liquid.

  According to the prepreg manufacturing apparatus for a printed wiring board according to the present invention, a long base material is sequentially conveyed from the unwinding side to the winding side including the coating unit for applying the resin liquid and the dryer. In the printed wiring board prepreg manufacturing apparatus manufactured in this manner, a solvent impregnation apparatus for impregnating the base material with a solvent is provided on the front side of the coating part.

  According to the method for manufacturing a prepreg for a printed wiring board and the apparatus for manufacturing a prepreg for a printed wiring board according to the present invention, it is possible to improve the resin coating property to the substrate more than before and increase the productivity of the prepreg. Become.

It is a schematic block diagram of the whole prepreg manufacturing apparatus which concerns on embodiment of this invention. It is a schematic fragmentary view of the principal part of the prepreg manufacturing apparatus which concerns on embodiment of this invention. It is a schematic sectional drawing of the base-material width direction before the solvent impregnation concerning embodiment of this invention. It is a schematic sectional drawing of the base-material width direction of the state which carried out the solvent impregnation to the base material which concerns on embodiment of this invention. It is a schematic sectional drawing of the base-material width direction of the state which carried out resin impregnation to the base material which concerns on embodiment of this invention, and resin-coated. It is a schematic sectional drawing of the base-material width direction of the uncoated part which generate | occur | produced when applying the resin liquid to the base material.

Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a schematic configuration diagram illustrating an entire prepreg manufacturing apparatus 1 according to an embodiment of the present invention.

The prepreg manufacturing apparatus 1 shown in FIG. 1 is provided on one side of an unwinding machine 2 for unwinding a base material 3, a plurality of guide rollers 4, 4,... A tank 6a, a solvent supply pump 6b, a solvent amount control device 6c, and a solvent impregnation device 6 including a solvent discharge unit 6d are provided. A first die coater 7 and a second die coater 8 are disposed on both sides of the substrate conveyance path 5 on the subsequent stage side, and the first die coater 7 is a resin liquid 13.
Are composed of a first resin liquid tank 7a, a first resin liquid supply pump 7b, a first resin amount control device 7c, and a first resin liquid discharge section 7d. The second die coater 8 is also connected to the first die coater 7. Similarly, it comprises a second resin liquid tank 8a, a second resin liquid supply pump 8b, a second resin amount control device 8c, and a second resin liquid discharge part 8d. Further, a heating dryer 9a, a heating dryer 9b, and a winder 10 that winds up the prepreg are provided on the subsequent stage side.

  As described above, the prepreg manufacturing apparatus 1 of the present embodiment is schematically configured.

  Then, operation | movement and a manufacturing method of a prepreg manufacturing apparatus are demonstrated in detail using FIG.1 and FIG.2. FIG. 2 is a schematic partial view of a main part of the prepreg manufacturing apparatus. The long base material 3 unwound from the unwinder 2 is transported while applying tension to the transport direction of the base material. The base material 3 is, for example, shown in FIG. 3, and FIG. 3 represents a schematic cross-sectional view in the width direction with respect to the transport direction of the base material 3. Reference numeral 15 denotes a fiber thread in which the base material 3 is formed of, for example, a fiber cloth. Reference numeral 16 denotes a cross section of the streak portion, which is an unevenness that can be locally formed in the longitudinal direction of the base material 3 in the base material plane when the long thin base material 3 is conveyed while applying tension in the longitudinal direction. It represents the streak.

  Then, the base material 3 is guided by the guide rollers 4, 4..., And then, as a solvent impregnation step for the base material 3, the base material 3 is provided by a solvent impregnation device 6 installed on one side of the base material conveyance path 5. The solvent 11 is impregnated from the one side surface. FIG. 4 shows the base material 3 impregnated with the solvent, and represents a schematic cross-sectional view of the base material 3 in the width direction. The base material 3 including the non-smooth streak portions 16 is impregnated with the solvent 11, and the solvent film 12 is formed on the front and back surfaces of the base material 3.

  The solvent discharge amount for impregnating the base material 3 with the solvent 11 is controlled by adjusting the pump rotation speed of the solvent supply pump 6b to a predetermined frequency by the solvent amount control device 6c. The solvent discharge amount is quantitatively detected by a flow meter. Although the solvent impregnation apparatus 6 is not specifically limited, The apparatus which can control the solvent discharge amount to the base material 3 is preferable. Furthermore, a sealed liquid feeding type solvent impregnation apparatus is preferable from the viewpoint of preventing foreign matter from entering the path until the solvent is discharged and reducing solvent volatilization.

  The solvent impregnation apparatus 6 according to the present embodiment uses a die coater as a preferred embodiment thereof.

  Moreover, the solvent impregnation apparatus 6 should just be installed so that a solvent impregnation may be carried out before the 1st die coater 7 of a post process, and one side of the base material conveyance path 5, or both sides, and also more than one unit It may be arranged.

  Subsequently, as a resin liquid coating process on the base material 3 on which the solvent film 12 is formed, the first die coater 7 and the second die coater 8 installed on both sides of the base material conveyance path 5 are applied to the base material 3. The resin liquid 13 is applied, and the resin film 14 is formed on both surfaces of the substrate 3.

  FIG. 5 shows a schematic cross-sectional view in the width direction of the base material 3 in which the base material 3 is impregnated with a solvent and resin-coated. By impregnating the base material 3 with the solvent 11 in advance, the resin liquid 13 diffuses and penetrates into the base material 3 while being compatible with the solvent through the solvent of the solvent film 12. A film 14 is formed.

Therefore, when the base material 3 is not impregnated with the solvent in advance and the resin liquid 13 is applied to the base material 3, for example, as shown in FIG. 16, the resin liquid 13 does not sufficiently permeate, and an uncoated part 17 is generated. However, before the resin liquid coating process to the base material 3 as in the present application, a solvent is applied to the base material 3. By providing the solvent impregnation step for impregnation, it is possible to eliminate or reduce the uncoated portion of the resin liquid coated surface of the substrate 3.

  The amount of resin liquid discharged from the first die coater 7 for applying the resin liquid 13 is controlled by adjusting the pump rotation speed of the first resin liquid supply pump 7b to a predetermined frequency by the first resin liquid amount control device 7c. ing. The resin liquid discharge amount is quantitatively detected by a calibration meter. The second die coater 8 has the same mechanism as the first die coater 7 and controls the resin liquid discharge amount. The first die coater 7 and the second die coater 8 are preferably arranged so that the amount of resin liquid can be controlled and applied to the substrate 3 from both sides of the substrate conveyance path 5. Furthermore, in order to prevent the presence of bubbles in the base material and to prevent the thin base material from being cut off during coating, the base material 3 is arranged separated by a certain distance in the transport direction, and coating is performed sequentially from one side. It is preferable to do this.

  Subsequently, the base material 3 on which the resin film 14 is formed, as a drying process, produces a prepreg by drying the resin film 14 that has been applied and formed by the heat dryers 9a and 9b. By this heat drying, the resin film 14 is made to be semi-cured while the solvent in the resin film is volatilized or the solvent is volatilized, and the prepreg can be manufactured.

  The finally manufactured prepreg is wound up by the winder 10.

  As the base material 3 according to the present embodiment, any appropriate material can be used as long as it is used for forming a prepreg for a printed wiring board. As such, for example, various glass cloths such as roving cloth, cloth, chopped mat, and surfacing mat, metal fiber cloth, other synthetic or natural inorganic fiber cloth; wholly aromatic polyamide fiber, wholly aromatic polyester Woven or non-woven fabric obtained from liquid crystal fibers such as fibers and polybenzozar fibers; Woven or non-woven fabric obtained from synthetic fibers such as polyvinyl alcohol fibers, polyester fibers and acrylic fibers; Woven fabrics and non-woven fabrics such as cotton cloth, linen cloth and felt Carbon fiber cloth; natural cellulosic cloth such as kraft paper, cotton paper, and paper-glass mixed paper. Although the thickness of the base material 3 is suitably selected according to the thickness of the prepreg to be produced, the thin base material of the base material 3 is 5 to 12 μm. For example, when producing a thin prepreg having a thickness of 20 μm, it is preferable to use a substrate having a thickness of 8 to 12 μm as the substrate 3 to be used.

  In addition, as the solvent 11 in the solvent impregnation step, any appropriate one can be used as long as it is used for forming a printed wiring board prepreg. For example, methyl ethyl ketone, acetone, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether acetate, 1-methoxy-2-propanol, and the like may be mentioned, and one or a mixture of two or more of these solvents may be used.

  Moreover, it is preferable from the point of compatibility with the resin liquid 13 that the solvent 11 uses the solvent contained in the resin liquid 13 applied to the base material 3. Furthermore, the solvent viscosity is preferably 1 mPa · S or less from the viewpoint of improving the impregnation property to the substrate.

  Further, in the solvent impregnation step of impregnating the base material 3 with the solvent 11, the amount of the impregnating solvent to the base material per unit area of the base material is calculated by the following formula as the base material holding solvent amount.

Substrate holding solvent amount (g / m ² ) = solvent discharge amount (g / min) ÷ conveying speed (m / min) ÷ solvent impregnation width (m)
Here, the solvent discharge amount is an amount by which the solvent is discharged from the solvent impregnation device 6 to the base material 3, and the transport speed represents the transport speed of the base material 3. The solvent impregnation width represents the length of the base material 3 in the width direction where the solvent 3 is impregnated with the solvent.

The amount of the solvent possessed by the base material is preferably 6.0 to 12.0 g / m ² , and more preferably 8.0 to 11.0 g / m ² . If the amount of the solvent retained by the substrate is less than 6.0 g / m ² , sufficient solvent cannot be impregnated on the front and back surfaces of the substrate 3, and the solvent film 12 may not be formed. Therefore, when the resin liquid 13 is applied to the subsequent base material 3, there may be a large number of uncoated portions on the non-smooth surface of the base material 3 with uneven lines. On the other hand, if it is greater than 12.0 g / m ² , the resin liquid may drip in the direction of gravity on the coated surface after the resin liquid 13 is applied after impregnation with the solvent, resulting in a poor appearance of the resin film 14.

  Moreover, the conveyance speed of the base material 3 becomes like this. Preferably it is 1-20 m / min, More preferably, it is 4-20 m / min. If it is less than 1 m / min, productivity may be deteriorated. On the contrary, if the conveyance speed of the base material 3 is higher than 20 m / min, the front and back surfaces of the base material 3 cannot be impregnated with a sufficient solvent, and the solvent film 12 may not be formed. For this reason, when the resin liquid 13 is applied to the subsequent base material 3, many uncoated portions 17 may be generated on the non-smooth surface of the base material 3 with uneven lines.

  Subsequently, as the resin liquid 13 in the resin liquid coating step, any appropriate one can be used as long as it is used for forming a prepreg for a printed wiring board. As such, for example, various thermosetting resins such as epoxy resins, polyimide resins, polyester resins, phenol resins, polyphenylene ether resins, polyphenylene oxide resins, curing agents, curing accelerators, solvents, etc. And the like prepared by blending and mixing. In addition, an inorganic filler or the like may be mixed in the resin liquid.

  The resin content ratio of the prepreg is preferably 40 to 80% by weight from the viewpoint of moldability of the prepreg in producing a printed wiring board using the prepreg, and the resin content range It is preferable to apply the resin liquid to the base material 3 so as to be inside.

The resin content of the prepreg shown here is a ratio of the weight obtained by subtracting the weight of the substrate 3 of the same area from the weight of the prepreg with respect to the weight of the prepreg in a predetermined area. If the resin content ratio is too small, for example, when a prepreg is laminated and molded on a circuit board, there is a possibility that an amount of resin sufficient to fill the circuit may not be ensured. Further, if the resin content is too large, the resin flowability at the time of prepreg molding is increased, and the dimensional stability may be deteriorated. As described above, according to the method and apparatus for manufacturing a prepreg for a printed wiring board, Before the resin liquid coating step on the base material 3, by providing a solvent impregnation step for impregnating the base material 3 with a solvent, the uncoated portion of the resin liquid coating surface on the base material 3 can be eliminated, Can be reduced. Thereby, the prepreg for printed wiring boards with good productivity can be manufactured.

(Example)
Examples according to the present embodiment will be specifically described below. By these examples, it is not restricted at all.

  Using the printed wiring board prepreg manufacturing apparatus shown in FIG. 1, the prepreg was manufactured and evaluated. Here, the conveyance speed of the base material 3 for producing the prepreg was set to 10 m / min, and the tension in the conveyance direction of the base material 3 was set to 150 N / m. Further, the solvent impregnation device 6 and the first die coater 7 are arranged at an interval of 300 mm in the substrate transport direction, and the second die coater 8 is further spaced from the first die coater 7 at an interval of 300 mm in the substrate transport direction. Arranged. The solvent impregnation apparatus 6 in the solvent impregnation step used a die coater to impregnate the solvent impregnation width of 1070 mm of the base material 3 with the amount of solvent contained in the base material shown in Table 1. The solvent discharge amount was set to each value in Table 1.

  A glass cloth is used for the base material 3, and the glass cloth base material style, the base material thickness, and the weight of the base material alone shown in Table 1 are used, and methyl ethyl ketone (MEK) is used for the solvent 11. .

Subsequently, in the resin liquid coating process, the resin liquid 13 was an epoxy resin liquid varnish containing methyl ethyl ketone and an epoxy resin and having a viscosity of 50 mPa · s. Moreover, about the coating to the base material 3 of the resin liquid 13, the resin liquid 13 was apply | coated to the base material 3 by width 1070mm so that it might become the resin content of a prepreg as shown in Table 1. And the base material 3 after the coating of the resin liquid 13 was heat-dried with the heat dryer 9a and the heat dryer 9b, and the prepreg of the prepreg thickness shown in Table 1 was produced. For the measurement of the resin content ratio of the prepreg, the weight of the produced prepreg and the glass cloth used at an area of 0.08 m ² was measured and calculated.

  About evaluation, the coating property to the base material 3 of the resin liquid 13 was evaluated after applying the resin liquid 13 to the base material 3 in the prepreg preparation process.

  About evaluation of the said coating property, after applying the resin liquid 13 to the base material 3 visually, evaluation was performed by the extent of generation | occurrence | production of the uncoated part of the resin liquid 13. FIG.

  After the resin liquid 13 is applied to the base material 3 by the second die coater 8, the presence of an uncoated portion of the resin liquid 13 within the range of 100 m in the longitudinal direction of the base material 3 with respect to the width of 1070 mm of the base material 3. It was counted and evaluated as the number of unexposed portions of the resin liquid, and determined according to the following criteria.

The number of existing resin liquid uncoated parts is 10 or more: bad quality (×), 5-9: good quality (◯), 0-4: very good quality (◎) Evaluation and pass / fail judgment were performed.
(Comparative example)
In the comparative example shown in Table 1, as a difference from the examples, the resin liquid 13 was applied to the base material 3 without impregnating the base material 3 with the solvent 13 in the solvent impregnation step, and a prepreg was manufactured. The prepreg was produced and evaluated in the same manner as in the Examples.

  From Comparative Examples 1-2, the number of resin liquid uncoated portions is greater than that of the Examples, and the quality after coating becomes poor. On the other hand, Example 1-2 has few generation | occurrence | production of the resin liquid uncoated part, and quality is favorable. This has shown that the coating property to the base material 3 of the resin liquid 13 can be improved and productivity can be improved on the same conveyance speed conditions as a comparative example.

DESCRIPTION OF SYMBOLS 1 Preprint manufacturing apparatus for printed wiring boards 2 Unwinder 3 Base material 4 Guide roller 5 Base material conveyance path 6 Solvent impregnation device 6a Solvent tank 6b Solvent supply pump 6c Solvent amount control device 6d Solvent discharge part 7 First die coater 7a 1 resin liquid tank 7b 1st resin liquid supply pump 7c 1st resin amount control apparatus 7d 1st resin liquid discharge part 8 2nd die coater 8a 2nd resin liquid tank 8b 2nd resin liquid supply pump 8c 2nd resin amount control apparatus 8d 2nd resin liquid discharge part 9a Heating / drying machine 9b Heating / drying machine 10 Winding machine 11 Solvent 12 Solvent film 13 Resin liquid 14 Resin film 15 Fiber thread 16 Stitch 17 Uncoated part

Claims (8)

  In the method for producing a prepreg for a printed wiring board, which includes a step of transporting a long base material in the longitudinal direction and applying a resin liquid to the base material and then drying it, before applying the resin liquid A method for producing a prepreg for a printed wiring board, wherein a solvent impregnation step of impregnating the base material with a solvent is provided in the step.   The thickness of the said base material is 5-12 micrometers, The manufacturing method of the prepreg for printed wiring boards of Claim 1 characterized by the above-mentioned. In the solvent impregnation step, the amount of the substrate-containing solvent that is solvent-impregnated into the substrate is:
Substrate possessed solvent amount (g / m ² ) = solvent discharge amount (g / min) ÷ conveyance speed of the substrate (m / min) ÷ solvent impregnation width (m) of the substrate
Wherein the substrate held by the solvent amount, method for producing a prepreg for a printed wiring board according to claim 1 or 2, characterized in that a 6.0~12.0g / m ^2.   4. The resin content of the prepreg is 40 to 80% by weight excluding the weight of the base material having the predetermined area from the weight of the entire prepreg having a predetermined area. The manufacturing method of the prepreg for printed wiring boards as described in any one of these.   In the manufacturing apparatus of a prepreg for a printed wiring board, which is produced by sequentially transporting a long base material from the unwinding side to the winding side, including a coating part for coating the resin liquid and a dryer, the coating An apparatus for producing a prepreg for a printed wiring board, wherein a solvent impregnation device for impregnating the base material with a solvent is provided on the front side of the section.   The said solvent impregnation apparatus is a die coater, The manufacturing apparatus of the prepreg for printed wiring boards of Claim 5 characterized by the above-mentioned.   The said resin liquid application part is a die-coater arrange | positioned at the both sides of the conveyance path of the said base material, Comprising: Resin liquid can be applied to both surfaces of the said base material. Prepreg manufacturing equipment for printed wiring boards. 8. The apparatus for producing a prepreg for a printed wiring board according to claim 7, wherein the die coaters arranged on both sides of the substrate conveyance path are arranged at regular intervals in the substrate conveyance direction.

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