JP2007262629A - Heat cleaning method for glass fiber fabric - Google Patents

Abstract

An object of the present invention is to provide a heat cleaning method capable of quickly removing organic matter from a glass fiber fabric by suppressing carbonization of the organic matter due to heating of the glass fiber fabric.
A glass fiber fabric of a bundle of glass fibers coated with an organic substance is brought into contact with an acetic acid aqueous solution, and then heat-treated at 350 to 700 ° C. for heat cleaning. Prior to the heat treatment, it is preferable to perform preliminary heat cleaning by continuously passing through an oxidizing agent treatment such as aqueous hydrogen peroxide or a heating furnace having an atmospheric temperature of 350 to 600 ° C.
[Selection figure] None

Description

  The present invention relates to a method for manufacturing a glass fiber fabric, and more particularly to a heat cleaning method for a glass fiber fabric.

  A glass fiber fabric used as a reinforcing material for a laminated board for printed wiring boards is manufactured by weaving a glass fiber bundle obtained by drawing and spinning molten glass with an air jet loom or the like as warps and wefts. Usually, glass fiber bundles are coated with a sizing agent during spinning or aging of glass fiber bundles to prevent fluff and yarn breakage due to mechanical wear during winding and weaving. The This sizing agent is an aqueous liquid of a composition mainly composed of starch or a water-soluble synthetic resin, an oil agent, a surfactant or the like.

  However, glass fiber woven fabric as a reinforcing material for laminated boards for printed wiring boards is not preferred to adhere organic matter to obtain adhesion between glass and resin, and is usually subjected to a heat treatment called heat cleaning after weaving. The sizing agent which is an organic substance adhering to the glass fiber bundle is removed.

  This heat cleaning method is generally a batch type heat cleaning in which a glass fiber woven body wound around an iron core is placed in a heating furnace having an atmospheric temperature of 350 to 500 ° C. for 15 to 100 hours to remove organic substances. . In addition, prior to this batch type heat cleaning, the efficiency of heat cleaning is improved by performing preliminary heat cleaning by continuously passing through a heating furnace having an atmospheric temperature of 350 to 600 ° C. while winding the roll of glass fiber fabric. In some cases, Furthermore, as a technique for improving the efficiency of heat cleaning, for example, according to Patent Document 1, an organic substance is removed to about 90% by a preliminary heat cleaning process, and an aqueous solution containing an oxidizing agent such as water or hydrogen peroxide solution is applied. Further, heat treatment is performed at about 100 to 630 ° C., and organic substances are removed in a short time.

However, if the glass fiber fabric is rapidly heat-treated at a high temperature, the organic matter adhering to the glass fiber bundle is carbonized, and the organic matter once carbonized is difficult to remove even after heating. In some cases, the surface of the glass fiber fabric remains in the form of black spots, resulting in a poor appearance of the glass fiber fabric or a poor insulation of the laminate. In particular, when a heat treatment in which the glass fiber fabric is continuously passed through a heating furnace having a high temperature atmosphere of 500 ° C. or higher is applied, carbonization of the organic substance proceeds rapidly, so that black spot-like appearance defects tend to occur. This cannot be said to be sufficiently solved even by the technique described in Patent Document 1 described above. Further, even when no black spot-like appearance defect occurs in the glass fiber fabric, when a prepreg is produced by impregnating the glass fiber fabric with a thermosetting resin, spot-like foreign matter is generated in the prepreg, or yellow Appearance defects that exhibit a changed color tone may occur.
Japanese Patent Laid-Open No. 09-012633

  The present invention suppresses the carbonization of organic matter due to heating of the glass fiber fabric, and without causing the appearance of black spotted foreign matters or yellowing in the glass fiber fabric or prepreg, and further quickly removing the organic matter from the glass fiber fabric. A glass fiber fabric heat cleaning method that can be removed is provided.

The present inventors have found that black spots are generated in a prepreg in which a heat-cleaned glass fiber fabric is impregnated with a resin, or the appearance defect that becomes a yellowed color tone is a black spot appearance on the surface of the glass fiber fabric. Similar to defects, it is caused by carbonization of organic substances on the glass fiber surface, and it is found that calcium atoms on the surface of the glass fiber are generated as nuclei, and the present invention is achieved based on this finding. I went to.

That is, the glass fiber fabric as a reinforcing material of the laminated board for printed wiring boards uses glass fibers having a glass composition generally referred to as E glass. E glass is a standard shown in the following Table 1, for example, the glass composition of the actually measured values in Table 1. E glass contains 16 to 25% by weight of calcium atoms as calcium oxide. For this reason, when a glass fiber fabric made of glass fibers having an E glass composition to which an organic substance is attached is exposed to a high temperature atmosphere, the organic substance tends to be carbonized with calcium atoms serving as a nucleus.

The reason for this is not clear, but the calcium content in the glass composition of the glass fiber elutes on the surface of the glass fiber to form calcium carbonate, and then cements with silicon oxide, which is the main component of the glass composition. This is because the organic substance in the film is formed into a microcapsule, and the organic substance inside the coated film no longer burns and decomposes and remains in a carbonized state on the glass fiber surface even after heating. Conceivable.

Therefore, in the heat cleaning method for glass fiber fabric of the present invention, the glass fiber fabric formed by weaving the glass fiber bundle coated with the organic sizing agent as warp and weft is brought into contact with an acetic acid aqueous solution, and then the glass fiber The woven fabric is put into a heating furnace and heat-treated at an atmospheric temperature of 350 to 700 ° C.
In the heat cleaning method of the present invention, since the glass fiber fabric is brought into contact with the aqueous acetic acid solution before the heat treatment, the glass fiber fabric can be efficiently heat cleaned without carbonized organic matter remaining on the glass fiber surface. it can. This is because when the glass fiber fabric is brought into contact with an aqueous acetic acid solution, the calcium carbonate on the surface of the glass fiber becomes a form of water-soluble calcium acetate and dissolves in the aqueous solution, so that the organic matter on the surface of the glass fiber is not coated. It is believed that there is.
In addition, unlike hydrochloric acid and nitric acid, acetic acid is an organic acid and a weak acid, so it does not alter the physical properties of the glass fiber and does not remain in the glass fiber fabric, affecting the physical properties of the printed wiring board. There is nothing to do.

The heat treatment in the heat cleaning method of the present invention may be carried out in a heating furnace in a wound state in which a glass fiber fabric is wound around an iron core, and may be performed by a batch method, or a glass fiber fabric is wound from a wound body of glass fiber fabric. While taking out, the glass fiber fabric may be continuously passed through a heating furnace. However, from the viewpoint of work efficiency, it is preferable to heat-treat by continuously passing through a heating furnace having an atmospheric temperature of 500 to 700 ° C. while unwinding the glass fiber fabric from the roll of glass fiber fabric.
In the heat cleaning method of the present invention, since the glass fiber fabric is brought into contact with the acetic acid aqueous solution prior to the heat treatment, the organic matter is suppressed from carbonizing even when passed through a heating furnace in a relatively high temperature atmosphere. Organic substances can be efficiently removed from the fiber surface.
Furthermore, in the heat cleaning method of the present invention, prior to bringing the glass fiber fabric into contact with the acetic acid aqueous solution, the glass fiber fabric is preferably brought into contact with the oxidizing agent aqueous solution to form an oxidizing agent treated fiber fabric. This is because the organic matter adhering to the glass fiber can be decomposed by bringing the glass fiber fabric into contact with the oxidizing agent aqueous solution, and the subsequent heat treatment can be performed efficiently.

Further, in the heat cleaning method of the present invention, the glass fiber fabric is continuously passed through a heating furnace at an ambient temperature of 350 ° C. to 600 ° C. while unwinding the glass fiber fabric before contacting the glass fiber fabric with the aqueous oxidizing agent solution or the acetic acid aqueous solution. It is preferable to perform preliminary heat cleaning to reduce the amount of organic matter adhering to the glass fiber. As a result, the treatment with the aqueous oxidizing agent solution or the aqueous acetic acid solution can be performed efficiently, the subsequent heat treatment is facilitated, and the heat cleaning can be performed efficiently.

  According to the heat-cleaning treatment method for glass fiber fabrics of the present invention, carbonization of organic matter due to heating can be suppressed, and heat-cleaning treatment can be efficiently performed without generating black spotted appearance defects of glass fiber fabrics. it can. In addition, the usual batch-type heat cleaning process involves heat-treating the glass fiber fabric in a wound state for a long time, so it is a rate-limiting process in the manufacturing process of the glass fiber fabric, and many iron cores are used. However, according to the treatment method of the present invention, a glass fiber fabric can be efficiently produced without preparing a large number of iron cores.

The glass fiber bundle is drawn and spun from molten glass and wound as a fiber bundle having a filament diameter of 3 to 13 μm and a bundle number of 50 to 400. At this time, for the purpose of preventing generation of fluff and yarn breakage due to mechanical wear, the glass fiber bundle is coated with a primary sizing agent mainly composed of organic matter. The organic material of the primary sizing agent is attached in an amount of 0.3 to 1.0% by weight based on the weight of the glass fiber.
Further, prior to weaving the glass fiber bundle as warp and weft, the warp is coated with a secondary sizing agent mainly composed of organic matter during aging. The organic substance of the secondary sizing agent is attached in an amount of 0.5 to 2.0% by weight based on the weight of the glass fiber.

In the glass fiber fabric heat cleaning method of the present invention, the glass fiber fabric obtained by weaving the glass fiber bundle to which the organic matter is adhered is brought into contact with an aqueous acetic acid solution. The method for bringing the glass fiber fabric into contact with the acetic acid aqueous solution may be any method such as dipping, coating, spraying, etc., but it is most efficient and preferable to bring the glass fiber fabric into contact with the acetic acid aqueous solution by dipping. In the case of immersion, the concentration of the acetic acid aqueous solution is preferably 0.05 to 3.0% by weight, and the immersion time is preferably 30 to 120 seconds.
In addition, after making a glass fiber fabric contact an acetic acid aqueous solution, in order to suppress taking-out of an acetic acid aqueous solution, it is preferable to perform a squeezing liquid and drying.

After bringing the glass fiber woven fabric into contact with the aqueous acetic acid solution, the glass fiber woven fabric is placed in a heating furnace having an atmospheric temperature of 350 to 700 ° C. and subjected to heat treatment.
As the first method of heat treatment, the glass fiber fabric is put in a heating furnace in an atmosphere of 350 to 450 ° C. in a wound state for 15 to 80 hours and heat-treated batchwise. At this time, since the glass fiber fabric is treated with an acetic acid aqueous solution, heat cleaning can be performed in a shorter time without carbonization of organic matter than when not treated with an acetic acid aqueous solution. In addition, when heating temperature and a heating time exceed this range, it will expose to a high temperature state for a long time, and the intensity | strength as a reinforcing material of a glass fiber fabric may fall.
As a second method of the heat treatment, the glass fiber fabric is continuously passed through a heating furnace while being unwound from the roll of glass fiber fabric. At this time, the ambient temperature is set to 400 to 700 ° C., and the heat treatment time is set to 30 to 300 seconds. If the ambient temperature of the glass fiber fabric surface in the heating furnace is less than 400 ° C., the organic matter will not be thermally decomposed, it is necessary to lengthen the heating time, the efficiency is lowered, and the strength as a reinforcing material of the glass fiber fabric tends to be lowered. It is in. Moreover, when the atmospheric temperature in a heating furnace exceeds 700 degreeC, there exists a tendency for the intensity | strength as a reinforcing material of a glass fiber fabric to fall. In addition, when the heat treatment time is less than 30 seconds, thermal decomposition of the organic matter may be insufficient, and when it exceeds 300 seconds, the strength as a reinforcing material of the glass fiber fabric may be reduced. The second heat treatment method is more efficient because it is completed in a shorter time than the first heat treatment method described above. Further, in the second method of heat treatment, in order to perform heat cleaning more efficiently, the atmosphere temperature of the glass fiber fabric surface is heated to a relatively high temperature of 500 to 700 ° C., and the heat treatment time is reduced. It is preferable to set to be 30 to 150 seconds. In addition, what is necessary is just to select this heat processing temperature and heat processing time suitably with the organic substance component and adhesion amount of a sizing agent, the glass composition of glass fiber, etc. For example, in the case of the glass fiber which consists of E glass composition, it is preferable that heat processing temperature is 500-650 degreeC, and heat processing time is 30-120 second.

  Furthermore, in the glass fiber fabric heat cleaning method of the present invention, it is preferable to contact the glass fiber fabric with the aqueous oxidizer solution prior to the step of bringing the glass fiber fabric into contact with the aqueous acetic acid solution. It is preferable that the oxidizing agent aqueous solution is a hydrogen peroxide solution. The method of bringing the glass fiber fabric into contact with an aqueous oxidant solution such as aqueous hydrogen peroxide may be any method such as dipping, coating, spraying, etc., but it is most efficient and preferred to contact the aqueous oxidant solution by dipping. When the glass fiber fabric is immersed in the hydrogen peroxide solution, the concentration of the hydrogen peroxide solution is preferably 0.5 to 5% by weight, and the immersion time is preferably 30 to 200 seconds. Furthermore, since ammonia improves the oxidizing power of hydrogen peroxide as a catalyst, the hydrogen peroxide solution preferably contains 0.05 to 3% by weight of ammonia. In addition, after making a glass fiber fabric contact an oxidizing agent aqueous solution, in order to suppress taking-out of oxidizing agent aqueous solution, it is preferable to perform a squeezing liquid and drying.

In the glass fiber fabric heat cleaning method of the present invention, prior to the step of bringing the glass fiber fabric into contact with an aqueous acetic acid solution, the glass fiber fabric is continuously passed through a heating furnace at an ambient temperature of 350 ° C. to 600 ° C. It is preferable to perform heat cleaning. Although the glass fiber fabric is entirely brown by this preliminary heat cleaning, the organic matter adhering to the glass fiber fabric can be reduced to 0.1 to 0.5% by weight with respect to the glass fiber weight. Therefore, after making a glass fiber fabric contact with acetic acid aqueous solution, heat processing can be performed easily and heat cleaning can be performed efficiently. In the preliminary heat cleaning, the heating time is preferably 30 to 200 seconds. If the ambient temperature or heating time exceeds the above range, the appearance of black spots on the surface of the glass fiber fabric may be caused.
In the heat cleaning method for glass fiber fabrics of the present invention, the step of contacting with the oxidant aqueous solution and the preliminary heat cleaning step may be used in combination. In this case, it is preferable that the glass fiber fabric is preheat-cleaned, then contacted with an aqueous oxidizer solution and then contacted with an aqueous acetic acid solution, because heat cleaning can be performed efficiently.

[Glass fiber fabric]
(1) Glass fiber woven fabric (IPC cloth style 2116 yarn used) composed of glass fibers having an E glass composition shown in the actual measurement values of Table 1 and having a starch-based sizing agent attached to 1.0% by weight with respect to the weight of the glass fibers. ECE225 1/0 0.7Z) was used as the glass fiber fabric (a).
(2) The glass fiber fabric (a) is heat-treated by passing through a heating furnace set so that the atmospheric temperature on the surface of the glass fiber fabric is 540 ° C. for 90 seconds, and the amount of organic matter deposited is reduced to 0.1% by weight. Glass fiber fabric (b).
(3) The glass fiber fabric (b) was immersed in a 0.1 wt% aqueous acetic acid solution for 60 seconds to obtain a glass fiber fabric (c).
(4) The glass fiber fabric (a) is immersed in 3.0% by weight of hydrogen peroxide containing 0.1% by weight of ammonia for 60 seconds, and then in 0.1% by weight of acetic acid aqueous solution. The glass fiber fabric (d) was dipped for a second.
(5) A glass fiber woven fabric (e) was prepared in the same manner as in the above (4) except that the glass fiber woven fabric (a) was replaced with the glass fiber woven fabric (b).

[Evaluation of ease of heat treatment]
The glass fiber fabrics (a) to (e) of 10 cm square are put into a heating furnace having an atmospheric temperature of 600 ° C., heat-treated, and the time until the YI value becomes 27 is measured with a color difference meter. It was set as the time until the fiber fabric became white. Moreover, the spot-like foreign material on this glass fiber fabric surface was observed, and the following reference | standard evaluated. The results are shown in Table 2.
A: No occurrence at all.
B: Slight occurrence is observed, but it is not a problem.
C: Occurs to the extent that becomes a problem.

[Heat treatment of glass fiber fabric]
The glass fiber fabrics (b) to (e) were passed through a heating furnace whose temperature was adjusted so that the ambient temperature on the surface of the glass fiber fabric was 600 ° C., and then heat-treated in a continuous manner.
Moreover, the wound body of glass fiber fabric (a), (b), (d) was put into the heating furnace with an atmospheric temperature of 400 degreeC, and was heat-processed by the batch type. In addition, since the time for heat-processing glass fiber fabric (a) is extremely long, the roll of glass fiber fabric was heat-processed only by the batch type.
The heating time of the glass fiber fabric is shown in Table 2, and the value of the heating time is a time set based on the evaluation result of the ease of the heat treatment described above, and the glass fiber fabric heat cleaning is performed stably. It is time that can be considered as time that can be.

[Strength evaluation of heat-cleaned glass fiber fabric]
Tensile strength was measured for the heat-treated glass fiber fabrics (a) to (d) based on JIS R3420 Glass Fiber General Test Method 7.4 Tensile Strength. The measurement results are shown in Table 2.

[Preparation of prepreg]
Heat-treated glass fiber fabrics (a) to (d) are immersed in 0.4% by weight of aminopropyltriethoxysilane, squeezed and dried, impregnated with an epoxy resin varnish having the following composition, and 125 ° C. for 500 seconds. By heating, a prepreg containing 45% by weight of a glass fiber fabric was obtained. The YI value of this prepreg was measured with a color difference meter, and the degree of coloring of the prepreg was evaluated. It can be judged that it is colored, so that this figure is large. The measurement results are shown in Table 2.
Araldite 8011: 75 parts by weight Epicoat 154: 9 parts by weight 2-ethyl, 4-methylimidazole: 0.2 parts by weight Dicyandiamide: 1 part by weight Methyl cellosolve: 15 parts by weight

[Production of laminates]
Four prepregs were stacked and heated and pressurized at 170 ° C. for 2 hours at a pressure of 2 MPa to produce a laminate. This laminate is cut into 4 cm square, left under a saturated vapor pressure of 133 ° C. for 2 hours, then floated in a solder bath at 260 ° C. for 20 seconds, and the appearance of the laminate is observed. evaluated. The evaluation results are shown in Table 2.
A: No swelling occurs at all.
B: Swelling is slightly generated, but neither the size nor the number is a problem.
C: Remarkably generated to the extent that blistering becomes a problem.

  ADVANTAGE OF THE INVENTION According to this invention, the heat cleaning process peculiar to the glass fiber fabric used for reinforcing materials, such as a laminated board for printed wiring boards, can be performed efficiently.

Claims (5)

  A glass fiber fabric heat-cleaning method comprising contacting a glass fiber fabric formed by weaving a glass fiber bundle coated with an organic substance with an acetic acid aqueous solution and then heat-treating the glass fiber fabric at an ambient temperature of 350 to 700 ° C.   The method for heat cleaning a glass fiber fabric according to claim 1, wherein the glass fiber fabric is a glass fiber fabric brought into contact with an oxidizing solution.   The method for heat cleaning a glass fiber fabric according to claim 1, wherein the glass fiber fabric is a glass fiber fabric that has been subjected to preliminary heat cleaning by continuously passing through a heating furnace having an ambient temperature of 350C to 600C.   2. The glass fiber according to claim 1, wherein the glass fiber fabric is a glass fiber fabric which is continuously passed through a heating furnace having an atmospheric temperature of 350 ° C. to 600 ° C., subjected to preliminary heat cleaning, and then contacted with an oxidizing agent aqueous solution. Heat cleaning method for textiles.   The method for heat cleaning a glass fiber fabric according to any one of claims 1 to 4, wherein the heat treatment is a process of continuously passing the glass fiber fabric through a heating furnace having an atmospheric temperature of 500 to 700 ° C. .