JPH1025657A - Flatting of glass woven cloth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for flatting a glass woven cloth without impairing a resin permeability, by which the glass cloth is capable of imparting an excellent water absorbency, heat stability and surface flatness to a laminated plate and responding to a requirement of densification of a printed circuit board. SOLUTION: This flatting of a glass woven cloth is performed by applying a corona electrical discharge machining on a gray fabric of a glass cloth to activate the glass surface, imparting 3-30wt.%, preferably 5-20wt.% solvent such as water to the activated glass cloth by a spray device, heat treating the solvent-imparted glass cloth by a heated roll 4 at 40-300 deg.C, preferably 60-200 deg.C, further continuously heat-press treating the heat treated glass cloth by a heat-press device 5 under 5-100kg/cm, preferably 10-70kg/cm linear load and thereafter carrying out not only a heat cleaning but also a treatment for retaining the shape of the treated glass cloth by introducing the pressed glass cloth into a heat cleaning device 8 in the method for flatting the glass woven cloth.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for flattening a woven fabric, particularly a glass cloth used as a base material of a printed wiring board.

[0002]

2. Description of the Related Art There is an increasing tendency for printed wiring boards to have higher density mounting, higher multilayers, and thinner boards, and accordingly, there is an increasing demand for characteristics of laminated boards as materials and glass cloth used as base materials. . The following summarizes the particularly important characteristics required for the laminated plate and the characteristics required for the glass cloth to be paired therewith. Required properties for laminated board: Water absorption and heat resistance → Required properties for glass cloth: Improved resin impregnation, water intrusion suppression Required properties for laminated board: Surface smoothness → Required properties for glass cloth: Surface irregularities Decrease

Among the requirements for these glass cloths, the requirements for improving the resin impregnating property and reducing the surface unevenness are mainly caused by the shape of the glass cloth, and are one of the physical processing of conventional textiles. It has been responding with a technique called opening. However, in regions where high levels of water absorption resistance and heat resistance are required, fiber-opened glass cloth is not sufficient, and the effect of suppressing the intrusion of water from the surface of the laminated board by the glass cloth is more expected.

It has been confirmed that the effect of suppressing the invasion of water by the glass cloth is exhibited by converging and flattening the yarn bundles forming the glass cloth. However, in this case, the impregnation of the resin into the yarn bundle is extremely deteriorated, which causes a problem such as a decrease in productivity of the laminated board. Therefore, application to glass cloth in a special field has been limited.

[0005]

SUMMARY OF THE INVENTION The present invention satisfies the required properties of resin impregnation, water intrusion suppression, and surface irregularities at the same time, and has a tendency to achieve high-density mounting, high multilayering, and thinning of printed wiring boards. It is an object of the present invention to provide a glass cloth that can respond to the following.

[0006]

Means for Solving the Problems As a result of diligent studies on the above-mentioned problems, the present inventor has found that flattening glass cloth without impairing the resin impregnating property is performed by physically processing the glass cloth in a green state. It becomes possible to
The present inventors have found that the water absorption, heat resistance and surface smoothness of a laminated board using this are significantly improved, and have completed the present invention.

That is, the present invention relates to a method of flattening a glass cloth woven fabric obtained by weaving a warp and a weft, wherein the woven fabric is a greige machine, a step of applying a solvent to the woven fabric, This is a method for flattening a woven fabric, comprising a step of heating the cloth and a step of continuously compressing the woven cloth. Further, the method is characterized in that the flattening method of the glass cloth comprises a series of continuous steps, and after the step of compressing the woven cloth, the step of maintaining the shape of the woven cloth by heating is also continuously performed. Have. Further, after the greige fabric is subjected to the activation treatment, the step of applying water as a solvent to the woven fabric, heating and compressing the woven fabric is performed by two rolls including one or more heating rolls. It is also characterized in that it is performed by at least one pair of compression rolls.
It is also characterized in that the activation treatment is corona discharge machining.

Hereinafter, the present invention will be described in detail. (I) greige fabric (a) The greige herein is a form immediately after the glass cloth woven fabric is woven, and the glass thread forming the woven fabric adheres organic substances such as a binder and a sizing agent. 1 shows a woven fabric in a crushed state, including a glass cloth using plastic-sized yarn.

(B) Flattening a woven fabric means that the yarns forming the woven fabric and further the single yarns constituting the yarns are uniformly distributed and rearranged on the woven fabric. For that purpose, it is necessary to create a state in which the yarn forming the woven fabric is easy to move, to move the yarn so as to be rearranged, and to maintain the state. However, when the yarns forming the woven fabric, and further, the single yarns constituting the yarns are rearranged on the woven fabric, the single yarns particularly move in the direction of closest packing,
The spacing between the single yarns is reduced, and as a result, the resin impregnating property of the glass cloth is reduced.

(C) In order to prevent this, it is necessary to have a filler finally removed between the single yarns, and the role is achieved by the presence of organic substances such as a binder and a sizing agent on the glass yarn. be able to. That is, in the flattening method of the present invention, the target glass cloth is preferably a green fabric, and in the flattening process, it is preferable that organic substances such as a binder and a sizing agent remain between single yarns as much as possible. As a result, although the cross-sectional shape of the yarn constituting the flattened glass cloth has a high degree of flatness, the cross-sectional area is equivalent to that of the yarn constituting the non-processed glass cloth, and no reduction in the resin impregnation property is observed. It is.

(Ii) Configuration of the flattening method: (a) Solvent application step; in order to facilitate the movement of the yarn including the single yarn, it is important to reduce friction between the single yarns as much as possible. It is desirable that a lubricant or the like be present on the yarn surface.
In the case of the present invention, what plays a role of the lubricant is an organic substance such as a binder and a sizing agent on the glass thread, and further, a solvent such as water is applied to the woven fabric to partially remove the organic substance on the glass thread. Eluting target and / or whole is effective against slippage between single yarns.

(B) Heating step: In addition, the viscosity of the organic substances eluted on the glass thread is reduced by increasing the temperature,
A more lubricating effect is exhibited. (C) Compression process: Uniform distribution and rearrangement of yarns including single yarns can be achieved by applying pressure continuously and uniformly. (D) Retaining the shape: Further, the rearrangement of the glass cloth is maintained by removing the solvent used as a lubricant or the solvent and the eluted organic substances, and the binder, glue, etc. on the glass thread. In order to achieve the flattened state, it is necessary to apply the pressure continuously and uniformly, and immediately remove the lubricant.

(Iii) Each aspect of the flattening method: The above flattening mechanism is specifically achieved by the present invention as described below. (A) Activation treatment: However, since greige is generally poor in wettability with water due to organic substances on the surface, in order to improve water impregnation, the glass surface to which a binder, a sizing agent, etc. are attached is activated. It is necessary to make it. For example, pretreatment such as corona discharge machining and plasma discharge machining is effective. In particular, corona discharge machining is a preferable method for activating the greige machine. As the processing conditions, the applied power is 0.1 kW to 4
0.0 kW, preferably 0.3 kW to 20.0 kW; frequency is 1 kHz to 120 kHz, preferably 5 kHz to
50 kHz; treatment time is 0.05 to 5 seconds, preferably 0.1 to 3 seconds.

(B) Type of solvent, etc .: A solvent to be used as a lubricant for the glass thread and the constituent single thread, and a binder, a sizing agent, etc. on the glass thread to act more effectively as a lubricant. (Hereinafter, simply referred to as a solvent) must be well adapted to and impregnated with the glass cloth and the glass thread bundle. The type of the solvent is not particularly limited as long as it acts as a lubricant, or a substance that can elute the binder on the glass thread, the sizing agent, etc., and an aqueous solution or an organic solvent can be used. Water is the most preferable solvent in consideration of the removal of the solvent, cost and the like.

(C) Method of applying a solvent: As a method of applying a solvent, a general liquid applying method such as a dipping method, a spray method, a coater method, a rotor dump method, a foam applying method, and the like can be applied.
Although not particularly limited in the present invention, a liquid applying method in which a binder, a sizing agent, and the like on glass are not dropped in the process is preferable, and a spray method, a rotor dump method, and the like are suitably used. (D) Amount of solvent to be applied: The amount of the solvent to be applied is 3% by weight to 30% by weight, preferably 5% by weight, based on the glass cloth to be applied.
% To 20% by weight. If the amount is less than 3% by weight, the effect of the solvent as a lubricant is small, and if it exceeds 30% by weight, dripping from the glass cloth occurs.

(E) Heating step: In order to further enhance the lubricating effect of the solvent, it is desirable to perform heating. The heating temperature of the glass cloth is 40 ° C to 300 ° C, preferably 60 ° C.
C. to 200 C. are selected. If the temperature is lower than 40 ° C., there is no heating effect, and if it is higher than 300 ° C., the solvent evaporates at once, which is not preferable. In the compression step described below, it is preferable that the pressure is applied while the solvent remains as much as possible. Therefore, it is more preferable that the heating is performed immediately before the pressure is continuously applied to the glass cloth.

As the heating method, general hot air, I
R can be applied in a heating furnace, application of high-pressure steam, microwave heating, contact with a heating roll, etc. It is used in the roll compression method generally used in the process of applying a continuous uniform pressure. A method in which the heated roll is used as a heated roll and heating is performed simultaneously with compression is efficient and preferable. Further, a combination of a compression heating roll and a general heating method is also possible.

(F) Compression step: Continuous uniform compression for uniform distribution and rearrangement of yarns including single yarns is achieved by roll compression. Roll compression consists of a combination of at least two rolls in pairs, and is performed by a plurality of roll pairs as needed. Compression pressure is 5 by linear pressure
-100 kg / cm, preferably 10-70 kg / cm
Is selected. If the linear pressure is less than 5 kg / cm, the effect of compression cannot be obtained, and if it exceeds 100 kg / cm, single breakage of the glass thread becomes remarkable due to the pressure.

(G) Shape maintaining step: Next, the rearranged and flattened state is maintained by a solvent serving as a lubricant or the solvent and eluted organic matter, a binder on a glass thread, a sizing agent, etc. , Specifically, by heating. In order to further maintain the flat state, it is necessary to heat immediately after the compression step to remove the lubricant. The heating method may be a normal drying method, and more efficiently by applying a general heat cleaning step of glass cloth. The heating temperature is set at 80 ° C. for efficient solvent removal and organic matter retention on the glass surface in the case of the solvent removal alone.
About 200 ° C. to 200 ° C., and when removing organic substances on the glass surface together with the solvent, 200 ° C. to 800 ° C.
The degree is desirable for burning organic substances and maintaining strength of the glass itself.

(H) Post-treatment: The glass cloth processed by the flattening method of the present invention may be treated with a surface treatment agent, for example, a silane coupling agent, after the above-mentioned high-temperature desizing treatment. (iii) Production of a laminated plate: Further, in order to produce a laminated plate using the glass cloth according to the present invention, a conventional method may be used.
For example, a glass cloth is impregnated with a matrix resin such as an epoxy resin to prepare a resin-impregnated prepreg,
It can be obtained by laminating one or a plurality of these and subjecting them to heat and pressure molding.

(Iv) Glass cloth: The flattening method of the present invention is generally used as a substrate for a printed wiring board.
The present invention can be applied not only to glass but also to glass cloth made of a material such as D, T, C, and H glass. Further, the weave structure of the glass cloth can be applied not only to ordinary plain weave but also to glass cloth such as nanako weave, twill weave and satin weave.

[0022]

EXAMPLES The present invention will be described in detail with reference to the following examples, which do not limit the scope of the present invention. <Evaluation Method of Glass Cloth> The evaluation of the glass cloth by the flattening method of the present invention was performed by the following method. Evaluation of Cloth Characteristics 1) Measurement of Cloth Thickness was measured according to JIS R 3420. 2) Measurement of cross air permeability Measured according to JIS L 1096. 3) Measurement of flattening A glass cloth was embedded in an epoxy resin or the like that was cured at room temperature, and the yarn cross section was cut out, observed with a microscope, and the yarn cross section shape was measured. Ratio of yarn width to yarn thickness (flatness = yarn width / yarn thickness)
From, the flattened state was determined. When the value of the flatness is large, it is determined that the flattening is performed.

4) Measurement of the cross-sectional area of the yarn The cross-sectional shape of the yarn was approximated by an ellipse, and the area was calculated using the yarn width and the yarn thickness obtained by the measurement of the flattening, and the area was calculated as the cross-sectional area of the yarn. Evaluation of Resin Impregnation A prepreg having the following resin composition was prepared, the appearance (remaining state of voids, transparency) was observed, and the impregnation state was visually judged. The results indicate that the impregnating property deteriorated in the order of →→ ○ → △ → ×.

Evaluation of Laminated Plate A prepreg having the following resin composition was prepared, and four prepregs were laminated. A copper foil having a thickness of 18 μ was laminated on both surface layers of the prepreg.
Under pressure and at 35 kgf / cm ² at 60 ° C. for 60 minutes, a double-sided copper-clad laminate was obtained. 1) Evaluation of surface smoothness The surface roughness (Rmax) of the warp and the weft in the 45-degree direction was measured with a surface roughness meter (SUFCOM E-MD S75A manufactured by Tokyo Seimitsu Co., Ltd.) to evaluate the surface smoothness. 2) Evaluation of water absorption and heat resistance The copper foil of the double-sided copper clad board is removed by etching, washed with water,
Air-dried, cut into 5 cm squares, and allowed to absorb water in a steam atmosphere at 120 ° C. for a predetermined time. From the weight change before and after the water absorption treatment,
The water absorption was determined and the water absorption was evaluated. Furthermore, it was immersed in molten solder at 260 ° C., and observed defects were observed. The evaluation was shown as (number of defective samples / total number of samples evaluated).

3) Resin composition Epicoat 5046B80 [manufactured by Yuka Shell Epoxy Co., Ltd.] 69.8% by weight Epicoat 180S75B70 [manufactured by Yuka Shell Epoxy Co., Ltd.] 14.1% by weight Dicyandiamide 1.6% by weight 2E4MZ 1% by weight Methyl cellosolve 7.2% by weight Dimethylformamide 7.2% by weight

(Example 1) The flattening process of the present invention was performed using the style 7628 cloth manufactured by Asahi Schwebel Co., Ltd. with the configuration shown in FIG. Each step was performed under the following conditions. Corona discharge machining: applied power → 1.5 Kw, frequency → 40 kHz, processing time → 1.5 seconds. Step of applying solvent: solvent → water, applying method → spray method, applied amount → 12% by weight. Heating process: 1) First stage, heating → contact with heating roll (120 ° C). 2) In the second stage, heating → compression process, one of the compression rolls is used as a heating roll (200 ° C). Compression step: linear pressure → 50 kg / cm. Shape holding process: Immediately after flattening, heat cleaning is applied continuously. ・ Temperature → 500 ° C., processing time → 5 seconds.

The glass cloth obtained through this step is
In a batch oven at 00 ° C., the surface is completely treated with a treating solution using a silane coupling agent (SZ6032: manufactured by Dow Corning Toray Silicone Co., Ltd.), dried, and dried for evaluation. Cross. Table 1 shows the evaluation results.

(Example 2) Using the style 7628 cloth manufactured by Asahi Schwebel Co., Ltd., the flattening process of the present invention was performed with the configuration shown in FIG. Each step was performed under the following conditions. Corona discharge machining: applied power → 1.5 Kw, frequency → 40 kHz, processing time → 0.5 seconds. Step of applying solvent: solvent → water, applying method → spray method, applied amount → 8% by weight. Heating process: 1) First stage, heating → contact with heating roll (120 ° C). 2) In the second stage, heating → compression process, one of the compression rolls is used as a heating roll (200 ° C).

Compression step: linear pressure → 30 kg / cm. Shape holding process: Immediately after flattening, heat cleaning is applied continuously. ・ Temperature → 500 ° C., processing time → 5 seconds. The glass cloth obtained through this step is completely desalted in a batch oven at 400 ° C., and subsequently treated with a treatment liquid using a silane coupling agent [SZ6032: manufactured by Dow Corning Toray Silicone Co., Ltd.]. Surface treatment, drying,
The glass cloth for evaluation was used. Table 1 shows the evaluation results.

Example 3 The flattening process of the present invention was performed using a style 216 cloth manufactured by Asahi Schwebel Co., Ltd. with the configuration shown in FIG. Each step was performed under the following conditions. Corona discharge machining: applied power → 1.5 Kw, frequency → 40 kHz, processing time → 0.5 seconds. Step of applying solvent: solvent → water, applying method → spray method, applied amount → 10% by weight. Heating process: 1) First stage, heating → contact with heating roll (120 ° C). 2) In the second stage, heating → compression process, one of the compression rolls is used as a heating roll (200 ° C).

Compression step: linear pressure → 40 kg / cm. Shape holding process: Immediately after the flattening process, heat cleaning process is applied continuously. ・ Temperature → 500 ° C, Processing time → 5 seconds Completely desizing the obtained glass cloth in a 400 ° C batch oven, followed by Silane coupling agent [SZ
6032: Dow Corning Toray Silicone Co., Ltd.
Surface treatment with a treating solution using the above method, and dried to obtain a glass cloth for evaluation. Table 1 shows the evaluation results.

Example 4 The flattening process of the present invention was performed using the style 216 cloth manufactured by Asahi Schwebel Co., Ltd. with the configuration shown in FIG. Each step was performed under the following conditions. Corona discharge machining: applied power → 1.5 Kw, frequency → 40 kHz, processing time → 0.5 seconds. Solvent application step: solvent → water, application method → spray method, application amount → 15% by weight. Heating process: 1) First stage, heating → contact with heating roll (120 ° C). 2) In the second stage, heating → compression process, one of the compression rolls is used as a heating roll (200 ° C).

Compression step: linear pressure → 30 kg / cm. Shape holding process: Immediately after flattening, heat cleaning is applied continuously. ・ Temperature → 500 ° C., processing time → 5 seconds. The obtained glass cloth is completely desalted in a batch oven at 400 ° C., followed by a silane coupling agent [SZ
6032: Dow Corning Toray Silicone Co., Ltd.
Surface treatment with a treating solution using the above method, and dried to obtain a glass cloth for evaluation. Table 1 shows the evaluation results.

(Comparative Example 1) Using a style 7628 greige cloth manufactured by Asahi Schwebel Co., Ltd., a continuous heat cleaning process applied while maintaining the shape as in the example was performed. After complete desizing, the surface was treated with a treatment liquid using a silane coupling agent (SZ6032, manufactured by Dow Corning Toray Silicone Co., Ltd.) and dried to obtain a glass cloth for evaluation. Table 1 shows the evaluation results.

(Comparative Example 2) Using a style 216 greige cloth manufactured by Asahi Schwebel Co., Ltd., a continuous heat cleaning process applied while maintaining the shape in the example was performed, and then, in a batch oven at 400 ° C. After complete desizing, the surface was treated with a treatment liquid using a silane coupling agent (SZ6032, manufactured by Dow Corning Toray Silicone Co., Ltd.) and dried to obtain a glass cloth for evaluation. Table 1 shows the evaluation results.

[0036]

[Table 1]

[0037]

As described above, when the method for flattening a woven fabric of the present invention is used, the water absorption (that is, the water infiltration of water) of the laminate can be achieved without impairing the impregnation of the resin into the glass cloth. Suppression), heat resistance and surface smoothness (ie, reduction of surface irregularities)
There is an effect that a glass cloth having excellent characteristics can be obtained. Therefore, by using this glass cloth, it is possible to provide a laminated board that can cope with the tendency of high-density mounting, higher layers, and thinner printed wiring boards.

[Brief description of the drawings]

FIG. 1 is a process diagram illustrating a flattening method according to the present invention.

[Explanation of symbols]

 A Green cloth glass cloth 1 Corona discharge machining 2 Spray device 3 Deflection roll 4 Heating roll (first stage heating) 5 Heat pressurizing device 6 Heat cleaning device 7 Flattened glass cloth

Claims (4)

[Claims] 1. A method for flattening a glass cloth woven fabric obtained by weaving warps and wefts, wherein the woven fabric is a greige machine,
And a step of applying a solvent to the woven cloth, a step of heating the woven cloth, and a step of continuously compressing the woven cloth. 2. The method for flattening a woven glass cloth according to claim 1, comprising a series of continuous steps, and a step of maintaining the shape of the woven cloth by heating after the step of compressing the woven cloth. The method for flattening a woven fabric according to claim 1, wherein the flattening is performed. 3. After activating the greige fabric, water is applied to the woven fabric as a solvent, and the woven fabric is heated.
3. The method of flattening a woven fabric according to claim 1, wherein the step of compressing is performed by at least one pair of two pairs of compression rolls including one or more heating rolls. 4. The method for flattening a woven fabric according to claim 3, wherein said activation treatment is corona discharge machining.