JPH05140873A - Production of glass cloth for reinforcing resin - Google Patents

Abstract

PURPOSE:To obtain a glass cloth, suitable for SMT(surface mounting technique) or multilayer board, excellent in varnish impregnating properties and good in dimensional stability and drill workability of the printed circuit boards and useful for the printed circuit boards. CONSTITUTION:A spinning sizing agent and warp sizing agent for glass cloth after weaving are prewashed with water or partially removed by washing with hot water, dried, heat-treated and completely desized. A surface treating agent is then applied thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a glass cloth for reinforcing a resin. For more details,
The present invention is a glass cloth useful for a printed circuit wiring board or the like on which electronic components are mounted, which significantly improves the varnish impregnation property, and has a dimensional stability of the obtained printed circuit wiring board and a drill. The present invention relates to a method for producing a glass cloth for resin reinforcement, which can improve workability.

[0002]

2. Description of the Related Art In recent years, with the shift to an advanced information society, in the field of information and communication that supports it, electronic parts, circuits, etc. are rapidly becoming denser, lighter, thinner and smaller, and electronic parts, etc. With respect to the printed circuit wiring boards on which the ICs are mounted, demands for higher reliability are further increasing due to high-density mounting and thinning. Surface mounting technology (SMT) that supports such high-density mounting is also rapidly advancing, which is accelerating the densification of printed circuit wiring boards. As the density of printed circuit boards increases, the trend toward thinner circuits of printed circuit wiring boards, smaller diameter of through holes, and multi-layering increases, and the adhesion strength of resist ink, film, etc. is reduced by the thinning of the boards for printed circuit wiring boards. Improvement of surface smoothness for improvement, reduction of drill diameter for reduction of small diameter through hole, breakage of drill due to increase of aspect ratio, and increase of hole misalignment, therefore improvement of drill workability is strongly desired. ..

Further, due to the development of surface mounting technology, it is expected that the dimensional change rate and warp / twist of these substrates will be reduced. In recent years, vacuum presses have become popular for such dimensional change rate and warp / twist reduction. , Which is one of the technologies that support high density. The advantage of this vacuum press is that the pressure is low and even over the prepreg, and
The fact that the voids in the prepreg disappeared is excellent. However, it is necessary to reduce the voids in the prepreg as much as possible in order to perform molding at a lower pressure, and from this viewpoint, further improvement of the varnish impregnation property to the glass cloth base material is desired.

On the other hand, a substrate for a printed circuit wiring board is a composite of an inorganic or organic fiber base material and a synthetic resin. As the base material, glass fiber, aramid fiber, fluororesin fiber or the like is used, and particularly glass. Fiber is mainly used because it is inexpensive and has excellent electric insulation. As a synthetic resin,
Epoxy resin, phenol resin, polyimide resin, fluororesin, etc. are often used.

Further, since a glass cloth used for a printed circuit wiring board usually has a spin glue and a warp glue for weaving adhered thereto, there is a heat treatment step as a step for removing them. It is general to perform heat treatment for 20 to 100 hours at around 350 to 450, and after heat treatment and desizing, a silane coupling agent is applied to the surface as an adhesive between the glass cloth and the synthetic resin. This surface-treated glass cloth is impregnated with a synthetic resin and heat-treated to form a so-called prepreg in a semi-cured state. A plurality of these prepregs are stacked, copper foil is placed on the outer layer, and heat-formed to form a copper-clad laminate. To create.

[0006]

However, the glass cloth used for the printed circuit wiring board as described above constitutes warps and wefts from strands of hundreds of filaments. Uses a sizing agent and a warp sizing agent as a sizing agent for spinning the generation of fluff due to filament breakage. Starch, wax, oil, and the like are used as the spinning paste, and polyvinyl alcohol, starch, acrylic paste, and the like are used as the warp paste, and these are attached to the warp and the weft. Since such a spinning paste and a warp paste bring the filaments into close contact with each other to make the shape of the strand round, the woven glass cloth has large irregularities, and even if it is heat-treated and desized. The morphology of the strands remains almost unchanged. Therefore, the filaments are in close contact with each other, which impedes the varnish impregnation property. The surface roughness of the obtained laminated plate was also large.

[0007] Further, since the properties of the laminated plate are such that the strands of the glass fibers are bundled, the homogenization of the glass fibers in the synthetic resin is lacking, and in order to cope with the recent required properties such as dimensional stability and drill workability. It was hard to say that it was enough. Therefore, as a means for improving the varnish impregnating ability into the glass cloth and improving the laminated plate characteristics, it is also proposed to reduce the focusing property due to the decrease in the amount of the spin sizing agent and the warp sizing agent,
The problem is that fluff occurs due to filament breakage due to insufficient adhesion of the sizing agent.

On the other hand, the woven glass cloth is heat treated to be desizing, and then the glass cloth surface-treated with a silane coupling agent or the like is physically processed by metal bar processing, ultrasonic processing or the like to unravel the glass fiber strands. However, flattening has been proposed, and it has been confirmed that there are some effects. However, in this case as well, fluff was generated due to contact with the glass cloth, and there was a problem in appearance and heat resistance.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, varnish impregnating property of glass cloth for printed circuit wiring, and dimensional stability of the obtained printed circuit wiring board, and a drill. In order to improve the processability, the spinning paste and warp paste attached to the woven glass cloth are partially removed by washing with water or warm water in advance, followed by heat treatment to completely remove the paste and then surface treatment. The present invention provides a method for producing a resin-reinforced glass cloth, which comprises treating the surface thereof with an agent.

The present invention will be described in detail below. First, in the method of the present invention, the woven glass cloth may be washed with water or warm water in either a batch system or a continuous system. It is preferable to use the continuous type, which is inexpensive in cost. That is, the woven glass cloth is continuously supplied to a bath in which water or hot water of which temperature is adjusted overflows, and is retained for a certain period of time to dissolve and remove the spinning paste agent and the warp glue agent, This is a method in which after squeezing out, it is squeezed with a padder roll or the like to further remove the sizing agent, and then dried by a dryer and wound up.

In this case, the temperature of the hot water used is not particularly limited. The treatment speed varies depending on the equipment such as the volume and drying capacity of the bath and is not particularly limited, but it is preferable to set the treatment speed such that the residence time of the glass cloth in the bath is 2 seconds to 60 seconds. If the residence time is shorter than 2 seconds, the amount of the sizing agent removed is small, and conversely, even if it is retained for an excessively long time, the effect reaches an equilibrium state and does not change so much. Or, the amount of overflowing hot water varies depending on the volume of the bath, the processing speed, the liquid temperature, etc. and is not particularly limited, but it is adjusted so that the amount of sizing agent attached after washing with water or warm water is 0.5% to 1.0%. Is desirable. If the overflow amount is small, the dissolving power is low, and if the overflow amount is large, there is a problem in cost. In addition, the traveling direction of the glass cloth and the flowing direction of water or warm water may be countercurrent. Further, it is preferable that the drawing pressure is such that the glass cloth does not wrinkle.

The glass cloth partially desized in this manner is heated at a heat treatment temperature of 350 ° C. to 450 ° C. for 20 hours.
After 100 to 100 hours, the sizing agent is completely desized and surface-treated with a surface treatment agent. As the surface treatment agent in this case, a silane coupling agent suitable for the synthetic resin used is generally selected. Further, the glass component of the glass cloth used in the present invention is preferably E glass, D glass, S glass, quartz glass or the like having excellent electrical characteristics, but is not particularly limited. Further, the single fiber diameter of the glass fiber and the thickness of the glass cloth are not particularly limited.

[0013]

In the present invention, since the spun glue and the warp glue of the woven glass cloth are partially removed in advance by washing with water or warm water, the adhesion between the filaments is reduced and the filaments are woven, so that the glass cloth is removed. The impregnating property of the varnish into the resin is remarkably improved, and the glass fibers in the resin are homogenized.

[0014]

The present invention will be described in more detail with reference to the following examples. Example 1 (1) ECG75 1/0 1.0 warp (weaving density 44/25 mm) in which a warp sizing agent PVA (polyvinyl alcohol) was attached to glass fiber threads at 1.0 wt% and weft ECG7
5 1/0 0.7Z (woven density 33 yarns / 25 mm) glass fiber yarn 180 μm thick plain woven glass cloth was continuously used in a bath with hot water at 50 ° C. at a cloth speed of 20 m / min. Was squeezed for 5 seconds, squeezed with a batter roll having a pressure of 0.5 kg / cm ² G for 1 minute in a dryer, and wound up. The amount of glue adhered to this washed glass cloth was 0.8 wt%.

Next, this glass cloth was heat treated at a temperature of 400 ° C. for 80 hours to completely desizing the sizing agent, and then 4.0 g of an active ingredient of silane coupling agent SZ-6032 (manufactured by Toray Dow Corning Silicone Co., Ltd.). Surface treatment was performed at a concentration of / 1. (2) 80 parts by weight of Epicoat 5045 (made by Yuka Shell), Epicoat 154 (made by Yuka Shell)
20 parts by weight, 3.2 parts by weight of dicyandiamide as a curing agent and a curing accelerator, 0.18 parts by weight of benzyldimethylamine,
35 g of an epoxy resin varnish (viscosity 600 cps <25 ° C>) consisting of dimethylformamide, methyl cellosolve and methyl ethyl ketone as a diluting solvent was added to a Petri dish.
Collect the sample, place it on the table of a stereomicroscope, and illuminate the transmitted light from the bottom. Next, the glass cloth test piece obtained in (1) above, which was cut into 2.5 cm square pieces, was immersed in a varnish in a Petri dish and the time until the capillary voids disappeared was observed with a stereomicroscope. It was measured. Table 1 shows the average values measured n = 5 times.

From Table 1, it is clear from the comparison with Comparative Example 1 below that the varnish impregnating ability of the glass cloth produced by the method of the present invention is remarkably improved. COMPARATIVE EXAMPLE 1 ECG75 1/0 1.0 A warp formed by adhering 1.0 wt% of a warp paste PVA to a glass fiber yarn of Z (weaving density 44 yarns / 25
mm) and a weft ECG75 1/0 0.7 Z (woven density 33 yarns / 25 mm) glass fiber yarn with a thickness of 180 μm was used for heat treatment at 400 ° C. for 80 hours to completely remove the sizing agent. After gluing, the silane coupling agent SZ6032 was surface-treated with a concentration of 4.0 g / 1 of active ingredient.

About this glass cloth, Example 1
The varnish impregnation property was evaluated in the same manner as in (b). The results are shown in Table 1. It can be seen that the varnish impregnation property is considerably inferior to that of Example 1 of the present invention.

[0018]

[Table 1]

Example 2 (1) 80 parts by weight of Epicoat 5045 (made by Yuka Shell Co., Ltd.) and Epicoat 1 were added to the glass cloth prepared in Example 1.
54 (manufactured by Yuka Shell) 20 parts by weight, dicyandiamide 3.2 parts by weight as a curing agent and a curing accelerator, benzyldimethylamine 0.18 parts by weight, dimethylformamide 20 parts by weight as a diluting solvent, methyl cellosolve 20 parts by weight, methyl ethyl ketone 15 parts by weight Was impregnated with the following epoxy resin varnish and then heat-treated at 150 ° C. for 5 minutes to prepare a prepreg having a resin content of 40 wt%. Eight sheets of this prepreg were stacked, and a laminate having a 35 μm copper foil as an outer layer was pressure-molded at a temperature of 170 ° C. and a pressure of 40 kg / cm ² for 60 minutes to obtain a copper-clad laminate. (2) With respect to the laminated plate obtained in (1) above, the dimensional change rate and the drill workability were evaluated according to the following specifications.

<1> Dimensional change rate JIS C-6486 (copper clad laminate for multilayer printed circuit) 7.
The measurement was performed using a three-dimensional coordinate measuring machine according to 14. <2> Drilling processability Drilling machine: ND-4K-18 (Hitachi Seiko Co., Ltd.) Drilling method: Drill diameter 0.4 mm, feed rate 27 mm
/ Sec, rotation speed 65000 rpm, plate thickness 1.6 mm x 3 stacked, 5000 hit contact plate 100 μm aluminum plate, bottom 1.
5mm Bakelite plate <3> Measuring method The hole position accuracy is measured from the NC origin and above the copper-clad laminate 3
The three-dimensional coordinate measuring machine (XYZA
X GT800D-31S manufactured by Tokyo Seimitsu Co., Ltd., n = 4
Five points were measured and the average value was calculated.

Table 2 shows these results.
As is clear from the comparison with Comparative Example 2 below, it can be seen that the glass cloth of the present invention is excellent in dimensional stability and drill workability. Comparative Example 2 A copper-clad laminate was obtained in the same manner as in Example 2 except that the glass cloth prepared in Comparative Example 1 was used.

Evaluations were made in the same manner as in Example 2 (2), and the results shown in Table 2 were obtained for the dimensional change rate and drill workability. It can be seen that it is considerably inferior to the second embodiment of the present invention.

[0023]

[Table 2]

[0024]

According to the present invention, the impregnating property of the varnish into the glass cloth is remarkably improved, and the obtained printed circuit wiring board has excellent dimensional stability and drilling workability. Therefore, a glass cloth for a printed circuit wiring board suitable for SMT and multilayer boards can be obtained.

Claims (1)

[Claims] 1. A spinning paste and a warp paste adhered to a woven glass cloth are partially removed in advance by washing with water or warm water and then heat-treated to completely remove the paste, and then treated with a surface treatment agent. A method for producing a glass cloth for resin reinforcement, comprising: