JP2005336289A - Apparatus and method for producing prepreg - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing prepreg by which the dispersion of viscosity or specific gravity is reduced, a response time required until the convergence to a set value is decreased, and the yield of a material is improved when a small amount of varnish is used, as the method for regulating the viscosity or the specific gravity when producing the prepreg for a copper-clad laminate; and to provide an apparatus for producing the prepreg. <P>SOLUTION: The method for producing the prepreg by continuously sending out a fibrous base material wound into a roll shape, impregnating the fibrous base material with a thermosetting resin varnish having a regulated viscosity and a specific gravity, regulating the amount of the resin by a coating amount-regulator, and semi-curing the varnish involves mixing a small amount of the resin varnish in-line by an impregnation vessel for impregnating the prepreg with the varnish, and a varnish-circulating device arranged so as to circulate the prepreg to the impregnation vessel. The apparatus for producing the prepreg is also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a prepreg manufacturing apparatus and a prepreg manufacturing method for a copper-clad laminate used in electronic equipment.

  As shown in FIG. 1, the prepreg is usually manufactured as follows. The fiber base material 1 is continuously fed out and impregnated with a resin varnish 2 whose viscosity or specific gravity is adjusted, and then the resin amount is adjusted by a coating amount control device 3 and the solvent is volatilized in a drying furnace 4. Here, the resin varnish 2 is in a semi-cured state and is manufactured by winding or cutting.

In order to adjust the viscosity or specific gravity of the conventional resin varnish 2, generally the resin varnish 2 is circulated between the viscosity / specific gravity adjusting tank 6 with the stirrer 5 and the impregnation tank 7, and the viscosity or specific gravity is measured in the process. When the measured value deviates from the set value, the resin varnish undiluted solution 8 or the diluting solvent 9 is introduced into the viscosity / specific gravity adjusting tank 6 as necessary, and stirred by the stirrer 5. However, in this method, the resin varnish undiluted solution 8 and the diluting solvent 9 are replenished so that the varnish is fed by the metering pump 10 before these charged solutions are uniformly dispersed in the viscosity / specific gravity adjusting tank 6. Variations in viscosity or specific gravity occur in various places. Due to this phenomenon, it takes time to adjust the target viscosity or specific gravity.
In addition, since the viscosity / specific gravity adjusting tank 6 is used separately from the impregnation tank 7, when the resin varnish 2 that is less than the controllable amount of the viscosity / specific gravity adjusting tank 6 is used in the production of the product, Surplus occurs and material loss occurs. Furthermore, since the viscosity / specific gravity adjusting tank 6 needs to be cleaned, the area to be cleaned is large, and secondary losses such as cleaning solvent and cleaning time occur.
In order to reduce the influence on the viscosity or specific gravity due to disturbance such as replenishment of the resin varnish undiluted solution 8 or solvent volatilization, the capacity of the viscosity / specific gravity adjusting tank 6 may be increased. Even if the variation is improved, the loss of time and materials required for the control is further increased.

  As a method for controlling the viscosity of a liquid, a method similar to that shown in FIG. 1 is often used as in Patent Document 1, and it is difficult to accurately control viscosity or specific gravity, making it difficult to manufacture a highly accurate prepreg.

JP-A-10-320058

In the first aspect of the invention, the fiber base material wound in a roll shape is continuously fed out, impregnated with a resin varnish whose viscosity or specific gravity is adjusted, the resin amount is adjusted by a coating amount control device, In the method for producing a copper-clad laminate prepreg for volatilizing a solvent, as shown in FIG. 2, an impregnation tank impregnated with a resin varnish, a circulation pipe attached to an impregnation tank having a continuous mixing device, a viscometer, and a hydrometer By circulating the resin varnish in the circulation system, the viscosity or specific gravity of the resin varnish is controlled in the circulation system, so that the viscosity or specific gravity variation is reduced to the target value ± 1% or less only by the amount of the resin varnish in the impregnation tank and the circulation system. A method of controlling and manufacturing a prepreg is provided.
In the invention according to claim 2, when the viscosity or specific gravity of the resin varnish is controlled, a control switching set value is provided separately from the set value, and when the viscosity or specific gravity is higher than the control switching set value, the calibration of the resin varnish is performed. By adding the amount of diluting solvent required to dilute from the line to the control switching set value, roughly adjust the viscosity or specific gravity, and if it is lower than the switching set value, fine-tune it with a known control method such as PID control or fuzzy control The present invention provides a method for producing a prepreg characterized in that the time required for the viscosity or specific gravity to converge to a set value is 10 seconds or less.

In the present invention, the resin varnish is circulated in the impregnation tank and the circulation pipe attached to the impregnation tank, the resin varnish stock solution and the diluting solvent are directly introduced into the circulation pipe system, and the uniform mixing is performed by the continuous mixing device provided in the circulation system. To reduce the viscosity or specific gravity variation in the circulation system. Further, according to the method of the present invention, a viscosity / specific gravity adjusting tank can be abolished, the amount of materials and cleaning solvent can be reduced, and the time required for setup is also reduced. .
In addition, when controlling the viscosity or specific gravity of the resin varnish, it is controlled in two stages: coarse adjustment that introduces the adjustment amount of the dilution solvent predicted from the current viscosity or specific gravity value, and fine adjustment by PID control or fuzzy control, etc. The method is configured to provide two stages of setting values, coarse adjustment and target setting values. If the viscosity or specific gravity is higher than the rough adjustment set value, the viscosity or specific gravity is roughly adjusted by adding the amount of diluent solvent required for dilution from the resin varnish calibration curve to the control switching set value. Alternatively, the present invention relates to a control method characterized in that the time required for the viscosity or specific gravity to converge to a set value is reduced to 10 seconds or less by fine adjustment by a known control method such as fuzzy control.

The prepreg manufacturing apparatus of the present invention is a prepreg manufacturing apparatus that can reduce variations in viscosity or specific gravity and can improve the yield of resin varnish and cleaning solvent.
The prepreg production method of the present invention is a prepreg production method that can reduce the time required for the viscosity or specific gravity to converge to a set value, and can reduce the setup time for viscosity adjustment at the time of product switching.

The manufacturing method of the prepreg for copper clad laminated boards of this invention is described below.
First, the object to be controlled is selected from viscosity and specific gravity based on the restrictions of the characteristics of the resin varnish and management items. Here, regarding the resin varnish that can be controlled by either the viscosity or the specific gravity, the same effect can be obtained regardless of which is controlled, and therefore an arbitrary control target is selected.
Next, in the control unit 11 shown in FIG. 2, after setting the viscosity or specific gravity at the time of prepreg production, the resin varnish stock solution 8 is supplied to the impregnation tank 7 by the metering pump 10. In this state, since the viscosity or specific gravity value of the resin varnish is higher than the impregnation condition at the time of prepreg production, it is necessary to dilute with the diluting solvent 9. The resin varnish is circulated in the impregnation tank 7 and the circulation pipe attached to the impregnation tank by the circulation metering pump 10, and the viscosity or specific gravity is measured by the viscometer 12 or the hydrometer 13 installed in the circulation system. Based on the measurement result, the control unit 11 performs arithmetic processing to calculate the required amount of diluted solvent. Next, the opening control valve 14 and the diluted solvent charging pump 15 are controlled to supply the diluted solvent into the circulation system. Thereafter, the value of the viscosity or specific gravity of the resin varnish is continuously measured, and the opening amount of the opening adjustment valve 14 is continuously adjusted to finely adjust the amount of the diluted solvent 9 charged.

  According to the above production method, a resin varnish having a stable viscosity or specific gravity can be supplied to the impregnation tank, and a prepreg can be produced with high accuracy.

Further, the viscosity or specific gravity of the resin varnish is controlled by switching the control method from the deviation between the set value and the current value, and reducing the response time until the viscosity or specific gravity converges to the set value.
As a basic viscosity control method, a known technique such as PID control or fuzzy control is used. However, in the viscosity or specific gravity control only by these controls, it takes time to converge because the viscosity or specific gravity that is gradually set while repeating hunting is reached. Therefore, as shown in FIG. 3, a control switching set value is provided, and when the viscosity or specific gravity is less than this set value, control is performed by a known technique such as PID control or fuzzy control, but the current value is greater than the control switching set value. In this case, the control unit 11 calculates the flow rate of the diluted solvent required from the calibration curve of the resin varnish and the flow rate of the circulation metering pump 10, and the indicated value of the flow meter 16 indicates the required flow rate of the diluted solvent. Until then, the opening degree adjustment valve 14 is opened, and stirring is performed by the continuous mixing device 17, and rough adjustment is performed at once to the control switching set value. Here, when the instruction value changes below the viscosity or specific gravity control switching set value, the control is switched to a known control such as PID control or fuzzy control, and the viscosity and specific gravity are continuously finely adjusted.
The control switching setting value is set within a range about 5% higher than the target viscosity or specific gravity value of the resin varnish, taking into account the characteristic variation during production of the resin varnish stock solution used, and is selected according to the properties of the resin varnish used. .

By the above control method, variations in viscosity or specific gravity in the circulation system can be reduced, and the time required for the viscosity or specific gravity to converge to the set value can be reduced.
The present invention can be applied to the adjustment of viscosity or specific gravity when a substrate such as glass fiber, paper, or film is impregnated or coated with a resin varnish such as epoxy or phenol.

  Hereinafter, the present invention will be described by way of examples.

Example 1
As shown in FIG. 2, the resin varnish is circulated through the impregnation tank and the circulation pipe attached to the impregnation tank, and the resin varnish stock solution and the diluting solvent are directly fed into this circulation system, and the continuous mixing device provided in the circulation system The viscosity and specific gravity were controlled by a method of uniformly dispersing and a method of switching the control method from the deviation between the set value of the viscosity or specific gravity and the current value. As the resin varnish for measuring the viscosity or specific gravity, a thermosetting epoxy resin varnish having a resin content of about 50% by weight dissolved and mixed in a methyl ethyl ketone solvent so as to have a viscosity of 300 mPa · s was used.
The temperature of the resin varnish was controlled to 30 ± 1 ° C., and the target viscosity was set to 100 mPa · s. The impregnation tank and the circulation system were filled with a total of 100 liters of resin varnish, and the viscosity was adjusted while circulating at a capacity of 30 liters / minute with a metering pump. As a result of the evaluation, the viscosity variation could be set to a set value ± 1 mPa · s or less (set value ± 1% or less). Further, the convergence time until the viscosity was stable (set value ± 1 mPa · s or less) was 5 seconds in the viscosity measuring section. Similar results were obtained for specific gravity control.

Comparative Example 1
As a result of the evaluation shown in FIG. 1 under the same conditions as in the examples (however, the viscosity adjustment tank capacity is 100 liters), the viscosity variation is set value ± 4 mPa · s (set value ± 4%). The convergence time until the viscosity was stable (set value ± 4 mPa · s or less) was about 900 seconds in the viscosity measuring section. Similar results were obtained for specific gravity control.

By applying the present invention, in this comparative experiment, the viscosity or specific gravity variation was reduced from ± 4% to ± 1%, and the time required to converge the viscosity or specific gravity could be reduced from 900 seconds to 5 seconds. The amount of cleaning solvent and the cleaning time could be reduced by 60%.
Thereby, by applying the present invention, the amount of cleaning solvent can be reduced, and stable viscosity or specific gravity control can be accurately performed.

It is a schematic diagram which shows the prior art example of a prepreg manufacturing method. It is a figure which shows the example of improvement of the viscosity or specific gravity adjustment of a resin varnish. It is a flowchart of viscosity or specific gravity control of a resin varnish.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fiber base material 2 Resin varnish 3 Coating amount control apparatus 4 Drying furnace 5 Stirrer 6 Viscosity / specific gravity adjustment tank 7 Impregnation tank 8 Resin varnish undiluted solution 9 Diluent solvent 10 Metering pump 11 Control unit 12 Viscometer 13 Hydrometer 14 Opening Control valve 15 Dilution solvent charging pump 16 Flow meter 17 Continuous mixing device

Claims (2)

The fiber base material wound in a roll is continuously fed out and impregnated with a thermosetting resin varnish whose viscosity or specific gravity is adjusted, the resin amount is adjusted with a coating amount controller, and the solvent is volatilized in a drying furnace. In the method for producing a prepreg for copper-clad laminate to be cured, a small amount of resin varnish is prepared in-line by an impregnation tank for impregnating the prepreg into the varnish and a varnish circulation device arranged to circulate the impregnation tank to produce the prepreg. The prepreg manufacturing apparatus characterized by the above-mentioned. In resin varnish preparation, when controlling viscosity or specific gravity, coarse adjustment to introduce the adjustment amount of dilution solvent predicted from the current viscosity or specific gravity value and fine adjustment by PID control or fuzzy control by deviation from set value The prepreg manufacturing method according to claim 1, wherein the varnish blending control is provided.

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