JP5217511B2 - Prepreg manufacturing method and prepreg manufacturing apparatus - Google Patents

Description

  The present invention relates to a prepreg manufacturing method and a prepreg manufacturing apparatus used for printed wiring boards and the like.

  A prepreg as a thermosetting resin-impregnated coating fabric used for a laminated board for printed wiring boards is usually produced as follows. That is, as shown in FIG. 2, the substrate 1 made of fibers is continuously unwound and immersed in an impregnation tank 4 storing a resin varnish obtained by diluting a thermosetting resin with an organic solvent, and then a squeeze roll 3 or a cut bar. The amount of the resin is adjusted, the solvent is volatilized in the drying furnace 6, the thermosetting resin is semi-cured, cooled, and a continuous prepreg is manufactured. To manufacture. At this time, the resin scraped off by the squeeze roll or the cut bar returns to the impregnation tank 4.

  Conventional prepreg manufacturing apparatuses are described in Patent Documents 1 and 2. Among these, double-sided coating using a die described in Patent Document 1 has a problem of poor impregnation. Further, the method of applying with a comma coater after pre-impregnation described in Patent Document 2 has a problem that the flatness is inferior.

  In order to solve these problems, a die coating with an adjusted coating angle is proposed in Patent Document 3, but depending on the type of resin varnish to be coated, the thickness of the glass cloth, etc., the removal of bubbles may be There is a problem that it is insufficient and inferior in impregnation.

Japanese Patent Laid-Open No. 10-314647 JP 2001-122992 A Japanese Patent Laid-Open No. 2004-290771

  An object of this invention is to provide the manufacturing method and manufacturing apparatus of a prepreg which are flat and excellent in the impregnation property.

  The present inventors have found that the above-mentioned problems can be solved by immersing a substrate made of a fiber cloth in a solvent or a resin varnish, and after drying, by performing double-sided coating with a die, and have completed the present invention. .

  That is, in the present invention, a base material made of a fiber cloth is immersed in an impregnation tank containing a solvent or a resin varnish, and after passing between two squeeze rolls or cut bars installed above the impregnation tank or after drying. Further, the present invention relates to a method for producing a prepreg characterized in that a resin varnish is applied to both sides by a pair of dies arranged opposite to both sides of a substrate conveyance path and dried.

  The present invention also relates to an impregnation tank, a squeeze roll or cut bar installed above the impregnation tank, at least two drying means, and a prepreg manufacturing apparatus having dies disposed opposite to both sides of a substrate conveyance path. .

  Further, according to the present invention, the drying means includes a first drying means and a second drying means, and the first drying means is provided in the substrate conveyance path between the squeeze roll or the cut bar and the die. The prepreg manufacturing apparatus is installed, and the second drying means is installed in the base material conveyance path behind the die.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method and manufacturing apparatus of a prepreg which reduced the bubble rate of the prepreg and the front-back difference, and were excellent in the impregnation property can be provided.

Hereinafter, the best mode for carrying out the invention will be described in detail with reference to FIG.
FIG. 1 is an overall schematic diagram showing an example of a manufacturing apparatus according to an embodiment of the present invention. The main structure of the apparatus is a drying furnace 6 having a conveying path in the vertical direction, an unwinding 7 for continuously unwinding the substrate 1, an impregnation tank 4, a squeeze roll 3 or a cut bar for adjusting the amount of resin. Is applied by the left die A10 and the right die B11 disposed opposite to both sides of the substrate conveyance path, and is wound by the winder 8 or cut by the cutting machine 9 to manufacture the device. .

  In addition, the left die A10 and the right die B11 installed on both sides of the substrate conveyance path are usually a manifold portion that holds the coating liquid between the upper die and the lower die, a land portion that is a flow path, and a lip portion that serves as a discharge port. The internal pressure measuring means for measuring the internal pressure and the liquid supply means for supplying the coating liquid are connected to each other.

  In FIG. 1, when the coating liquid is supplied into each die by the liquid supply means, it remains in the manifold portion formed inside. The coating liquid equalizes the pressure distribution in the width direction in the manifold portion, passes through the land portion, is discharged from the lip portion, and is applied to the surface of the substrate.

  The base material carried in between the dies disposed opposite to both sides of the base material conveyance path has air sandwiched between the spaces between the fibers. In the opposite die coating method, when the varnish is directly applied from the die facing the substrate, the force that the resin varnish penetrates into the substrate is small, and the air inside the substrate may remain inside .

  Below, the case where the manufacturing apparatus of FIG. 2 is used is described as an example about the prepreg manufacturing method of this invention. The substrate 1 made of fiber cloth is continuously unwound from the unwinding 7 and immersed in a resin varnish in which the resin is diluted with a solvent or an impregnation tank 4 in which the solvent is stored, and then is extra in either a squeeze roll 3 or a cut bar. Remove any resin varnish or solvent and flatten.

  The solvent is volatilized in the drying furnace 6, the resin is made into a semi-cured state, cooled, and the resin varnish obtained by diluting the resin with the solvent is supplied from the liquid supply means to the die A10 and the die B11. The resin varnish is applied simultaneously. Thereafter, the solvent is volatilized in the drying furnace 6 to make the resin semi-cured, cooled, and a continuous prepreg is manufactured, and then wound by the winder 8 or cut by the cutting machine 9 as before. .

  Examples of the substrate made of the fiber cloth used in the present invention include a glass cloth substrate and a paper substrate. Examples of the resin used for the resin varnish include a phenol resin, an epoxy resin, a polyimide resin, and a bismaleide-triazine resin. Thermosetting resins, fluororesins, polyphenylene ether resins, and other thermoplastic resins can be used.

  Moreover, as a solvent used as a dilution liquid of a resin varnish or as an impregnation liquid in an impregnation tank, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, etc. can be used, for example.

Below, the Example of the method of manufacturing a prepreg using the prepreg manufacturing apparatus shown in FIG. 2 is described in detail.
Example 1
A glass cloth having a thickness of 96 μm was used as the substrate. As a resin varnish to be applied to the glass cloth from a die, 100 parts by weight of a phenol novolac type epoxy resin, 60 parts by weight of a cresol novolac resin, 0.5 parts by weight of ethylmethylimitazole, and 90 weights of filler such as aluminum hydroxide. A resin varnish having a resin content of 70% by weight obtained by diluting a resin composition consisting of parts with a methyl ethyl ketone solvent was used.

  The resin varnish filled in the impregnation tank was prepared by diluting the above resin composition with a methyl ethyl ketone solvent and using a resin varnish having a resin content of 30% by weight. Similarly, resin varnishes for various resins were obtained by diluting with a solvent.

  The glass cloth substrate was supplied at a rate of 4 m / min, immersed in an impregnation tank 4 storing a resin varnish with a resin content of 30% by weight, and then the excess resin varnish was scraped off with a cut bar. Then, the thermosetting resin was made into a semi-cured state, and a resin varnish having a resin content of 70% by weight was simultaneously applied to both surfaces of the substrate by the die A10 and the die B11. After the die coating, the solvent was volatilized in a drying oven to prepare a semi-cured prepreg.

The obtained prepreg had a good appearance. When the cross section of the prepreg was observed with a microscope, both the front and back resin layers on the glass cloth had a uniform thickness of 25 μm.
In order to check the bubbles present inside, the cross section of the prepreg was observed with a microscope, the presence or absence of bubbles was counted in the overlapping portion of the weft and the warp, and the ratio was defined as the bubble ratio. As a result, the bubble rate was 60%.

Example 2
A prepreg was produced in the same manner as in Example 1, except that a glass cloth having a thickness of 20 μm was used instead of the glass cloth having a thickness of 96 μm. Both the front and back resin layers on the glass cloth had a uniform thickness of 10 μm, and the front and back thickness was 1%.

Example 3
As a result of producing a prepreg in the same manner as in Example 1 except that the resin varnish filled in the impregnation tank was replaced with a resin varnish with a resin content of 30% by weight, and a resin content of 45% by weight was used. Both the front and back resin layers had a uniform thickness and a cell ratio of 70%.

Example 4
As a result of producing a prepreg in the same manner as in Example 2 except that the resin varnish filled in the impregnation tank was replaced with a resin varnish with a resin content of 30% by weight and a resin content of about 45% by weight was used, a glass cloth was obtained. Both the upper and lower resin layers had a uniform thickness, and the bubble ratio was 1%.

Comparative Example 1
Without performing immersion in the impregnation tank, flattening with a cut bar, and drying, the substrate was conveyed from the unwinding 7 to the die, and the prepreg was manufactured in the same manner as in Example 1 only in die coating and the subsequent steps. . As a result, the bubble ratio of the obtained prepreg was 80%.

Comparative Example 2
As a result of producing a prepreg in the same manner as in Comparative Example 1 except that a glass cloth having a thickness of 20 μm was used instead of the glass cloth having a thickness of 96 μm as the base material, the cell ratio of the obtained prepreg was 2%. .

1 is an overall schematic diagram showing a prepreg manufacturing apparatus according to an embodiment of the present invention. It is the whole schematic diagram which shows the manufacturing apparatus of the conventional prepreg.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Resin varnish 3 Squeeze roll 4 Impregnation tank 5 Guide roll 6 Drying furnace 7 Unwinding 8 Winding machine 9 Cutting machine,
10 Die A
11 Die B
12 Metering pump A
13 Metering pump B

Claims (1)

  An apparatus for producing a prepreg having an impregnation tank, a squeeze roll or cut bar installed above the impregnation tank, at least two drying means, and dies disposed opposite to both sides of the substrate conveyance path.

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