JPH04197712A - Manufacture of prepreg - Google Patents

Abstract

PURPOSE:To attempt to decrease burden of vacuum suction and treatment of exhaust gas by substituting a solvent vapour for air by passing a base material through a heated solvent vapour, introducing then it into a vacuum room wherein remaining air and part of the solvent vapour are removed under vacuum and impregnating it with a resin soln. CONSTITUTION:A long base material 10 wound on a roll is introduced into a solvent condensing room A wherein the base material 10 is pinched by means of rolls 21 and a solvent vapour from a heated solvent vapour room D penetrates into the base material and air in the base material is substantially substituted with a heated solvent vapour. The base material 11 substituted with the solvent vapour is introduced into a vacuum room B wherein the pressure is set at several hundreds mmHg through vacuum seal rolls. Sealing by means of the inlet rolls 22 of the vacuum room B makes that air carried in the vacuum room B is extremely little and majority is the solvent vapour and the amt. of air corresponds to the partial pressure and an effect which is similar to substantial decrease in pressure to the partial pressure can be obtd. The base material 12 wherein the remaining air and part of the solvent are removed in the vacuum room B is introduced into a resin soln. bath C through outlet rolls 23.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement in the manufacturing method of PlJ, 7' leg, which is suitably used for laminates, structural materials, and other uses. The method is characterized in that after the base material is passed through solvent vapor to replace the solvent vapor, a portion of the base material is removed in a closed pressure reduction system and immediately introduced into the resin solution.

Compared to the conventional vacuum impregnation method, the method of the present invention has substantially no or very little air flowing into the decompression chamber, so the conventional decompression power is converted to cooling and heating, and the required power is almost eliminated. This makes it possible to do this, and almost eliminates the need for exhaust gas treatment. In addition, for the solvent pre-impregnation method, it is possible to reduce the amount of solvent mixed into the resin solution tank to 1/200 or less at a reduced pressure of several hundred mmHg, and since only a small amount is replenished, the resin solution ( Since the solvent does not flow out during the process (fabrication process), there is no need to control the resin solution concentration. Moreover, since the air removal operation is performed by a gas/gas replacement operation, it is possible to achieve much greater operability (speed, therefore, it is possible with small equipment) compared to a method using a liquid.

[Conventional technology and its problems]

Traditionally, the mainstream manufacturing method for prepreg used in the manufacture of laminates, structural materials, and other products used in electrical applications has been to directly immerse the reinforcing base material in a resin solution (direct impregnation method■). However, there is a problem in that air remains in the prepreg in some of the fine continuous gaps in the fine monofilaments of the reinforcing base fibers. As a solution to this problem, methods have been proposed such as preliminary impregnation with a diluted resin solution or solvent and then main impregnation (pre-impregnation method ■), and method of immersing the resin solution in a reduced pressure chamber (vacuum impregnation method ■). ing.

In the case of the pre-impregnation method (■), if the pre-impregnation is completely achieved and it penetrates into the minute gaps, a good prepreg can be obtained. There is a problem in that the resin solution is diluted, and furthermore, the amount of the solvent carried in tends to fluctuate depending on temperature and other factors, making it difficult to control the concentration of the resin solution. In addition, in the case of the vacuum impregnation method (2), by maintaining a sufficient degree of vacuum (e.g. about 1QmmHg), a good prepreg can be obtained.Since the reinforcing base material has a continuous gap (orifice model), it is difficult to seal with a roll. , it is essential to increase the size of the vacuum pump. Moreover, in the large amount of exhaust gas generated during vacuum suction, it is inevitable that solvent from the resin solution tank will be mixed in, so there may be a risk of explosion in some cases. This created new problems.

[Problem to be solved by the invention]

As a result of intensive studies to solve the above problems, the present invention has been completed by discovering a method that combines solvent vapor replacement and removal using a closed chamber.

That is, the present invention provides a prepreg manufacturing method in which a base material is impregnated with a resin liquid and dried by heating, in which the base material is passed through a heated solvent vapor to substantially replace air with the solvent vapor, and then the base material is passed through a heated solvent vapor to substantially replace the air with the solvent vapor. A prepreg manufacturing method characterized by immediately impregnating with a resin liquid after removing a portion of the remaining air and solvent vapor under reduced pressure, and the method uses the same solvent as the resin liquid for the heated vapor. or the resin liquid is a solvent-free resin liquid.

The present invention also provides, as the impregnation device, a solvent condensation chamber [A] equipped with a cooler, a heated solvent vapor chamber CD adjacent to the solvent condensation chamber A, the inlet and outlet of which are sealed with rolls, and equipped with a heater. ], a decompression chamber (B) adjacent to the heated solvent vapor chamber, the inlet and outlet of which are sealed by rolls, and a structure directly connected to the exit roll of the decompression chamber B, with the entire surface of the exit roll filled with resin liquid. This is a prepreg manufacturing method characterized by using an impregnating apparatus having at least a resin liquid tank [C].

The configuration of the present invention will be explained below.

The base material of the present invention refers to ordinary electrical, electronic materials, structural materials,
Other long reinforcing base materials used include, but are not limited to, kraft paper, linter paper; E glass, S glass, D glass, quartz glass, other types of glass, silicon carbide and other types of ceramics. Woven or non-woven fabrics such as carbon fiber woven fabrics or non-woven fabrics; fibers such as alumina and mica; wholly aromatic polyamides, fluorine V
=, heat-resistant engineering plastic fiber woven fabrics such as polyphenylene sulfide polyetheretherketone, polyetherimide, fully aromatic polyester, etc.
Non-woven fabric or porous sheet: Mixed fabric, non-woven fabric or paper made by mixing the above-mentioned fibers; Woven fabric or non-woven fabric using threads made by combining the above-mentioned fibers.

Examples of the solvent include acetone, methyl ethyl ketone, toluene, xylene, dimethylformamide, N-methylpyrrolidone, methanol, and other solvents commonly used for preparing resin solutions. In addition, more stable solvents such as chlorocene, freon, dichloromethane, trichloroethane, and water, which are different from those used in the resin solution, may be removed under reduced pressure when increasing the amount of solvent (increasing the degree of vacuum) or when the substrate used is one of these solvents. It can be used if it is not violated by solvents.

The resin liquid is not particularly limited, and can be either a resin solvent solution using a solvent or a solvent-free resin liquid, and those used for various purposes like the above-mentioned base material can be used. Specific examples include phenol resin, epoxy resin, unsaturated polyester resin, polyimide resin, cyanate ester resin or cyanate ester-maleimide resin composition, cyanate ester-epoxy resin composition, cyanate ester-maleimide. Examples include cyanate ester resins such as epoxy resin compositions, resins produced by polycondensation using dimethoxymethylbenzene as the main raw material (trade name "Zyrotsu Resin"), and thermosetting resin compositions mainly composed of these resins. .

Next, in order to facilitate understanding of the manufacturing method of the present invention, a description will be given with reference to the accompanying drawings.

FIGS. 1 and 2 are schematic diagrams of the impregnating process portion of the prepreg manufacturing apparatus of the present invention.

1 and 2, a long base material [10] wound on a roll is introduced into a solvent condensation chamber (A). The length, residence time, or degree of cooling is sufficient to ensure that the solvent vapor from the heated solvent vapor chamber is cooled and becomes a liquid.The base material 10 is then sandwiched between the rolls [21]. Here, the solvent vapor from the heated solvent vapor chamber [D] pressurized slightly higher than normal pressure enters the base material, and the air in the base material is substantially replaced by the heated solvent vapor, and the heated solvent The solvent vapor is introduced into the steam chamber.This operation of replacing the solvent vapor with air using the roll 21 reduces the pressure difference between the atmospheric pressure part (condensation chamber A) and the heated solvent vapor chamber to a small range of several mmHg to several tens of mmHg. It can be implemented with a small gap, there is no major problem with sealing properties, etc., and it is also possible to replace it with a simple gap.

The heated solvent vapor chamber is provided with a heater for heating the solvent vapor or maintaining the heated vapor state. Here, the air in the fine gaps in the substrate is further diffused into the solvent vapor and replaced by the solvent vapor. As a result, the air in the fine gaps becomes a base material [ll] that is substantially replaced by solvent vapor.

The base material 11 is a vacuum seal roll C22] (illustrated as a double roll, in consideration of the passage of the joint portion of the base material.

), and is introduced into a reduced pressure chamber [B] which is usually set at a pressure of several hundred mmHg or less. The sealing by the inlet roll 22 of the reduced pressure chamber B does not require maintaining the degree of reduced pressure (degree of vacuum) as in the conventional vacuum impregnation method.

In other words, since the amount of air carried into the decompression chamber B is very small and most of it is solvent vapor, the amount of air is equivalent to its partial pressure, and the same effect can be obtained as substantially reducing the pressure to the partial pressure. is possible. The base material [12] from which residual air and solvent vapor have been partially removed in the vacuum chamber B is transferred to the exit roll [2].
3] into the resin solution tank C. The rolls 21, 22, and 23 used in the roll are preferably made of a fluororesin, a polyolefin resin, or a silicone resin with at least the surface having excellent solvent resistance.

In the resin solution tank C, 13 resin-impregnated substrates (13 in number) are impregnated with the resin solution to the minute gaps of the substrate under conditions of room temperature to 80° C. for several seconds to 10 minutes, and are led to a heat drying step. Here, if the resin solution oozes out from the exit roll from the resin solution tank C to the decompression chamber B side, it becomes a problem if the pressure difference is large. However, the present invention is not particularly harmful because the pressure in the vacuum chamber is usually much higher than in the past, and the same solvent used in the festival can be used.

The degree of vacuum in the vacuum chamber is preferably set to such a pressure that solvent vapor does not condense on the inlet roll of the resin solution tank C.

In the above operation, a vacuum pump is connected to the decompression chamber B via a cooler, and the solvent vapor is recovered as a liquid in the cooler, converted into heated solvent vapor in the solvent evaporator, and then returned to the heated solvent vapor chamber. is circulated. Further, the solvent condensed in the condensation chamber A is also introduced into the solvent evaporator, where it is turned into vapor, and then introduced into the heater in the heated solvent vapor chamber for circulation use. The exhaust gas from the vacuum pump is treated depending on the type of solvent used.

By heating steam displacement and depressurization using the equipment shown in this figure, the load on vacuum sealing, vacuum pump load, exhaust gas treatment, etc. is significantly reduced, and resin solution concentration control is no longer required.
It is possible to manufacture a base material impregnated prepreg in which even minute gaps in the base material are sufficiently impregnated with resin.

The reason why control of the resin solution concentration is unnecessary is as follows. In other words, the volume of a gas in a normal organic solvent compared to a liquid is 100 to 100°C in the range of boiling point to boiling point +5°C under normal pressure.
It is about 250 times (several hundred times in the case of small molecular weight substances such as water). Therefore, the amount of solvent carried into the resin solution tank C together with the base material is such that the pressure in the decompression chamber is 1/2 to 1/1 of normal pressure.
When it is about 0, it is 1/1 compared to the solvent pre-impregnation method.
Since the concentration is reduced to 00/(2-10)-1/(200-1000) or less, there is substantially no decrease in the concentration of the resin solution in the resin solution tank C.

Moreover, the mixing of a small amount of solvent is expected to have the effect of promoting the penetration of the resin solution between fine base materials.

Although the present invention has been explained above with reference to the drawings, the present invention is not limited to the above-described drawings. First, the base material is passed through solvent vapor to remove most of the air. Various modifications can be made, except that the material is treated in a closed system to remove air along with excess solvent vapor and impregnated with resin solution.

For example, solvent vapor displacement is usually performed by replacing the roll 211 with a simple narrow gap; heating means such as a heated solvent vapor chamber are replaced by known methods such as heating roll contact, pressurized steam heating plate, electric heating, infrared rays, etc. Select as appropriate from heating and others; Change the roll seal to a double-rope belt roll or other as appropriate; Place a resin solution tank on the exit roll of the vacuum chamber; Pressurize the resin impregnation tank C. In addition, the sizes of the condensation chamber, heated solvent vapor chamber, resin solution tank, etc., and the vertical and horizontal positional relationships may be changed as appropriate. It is also possible to use a mixed solvent for the resin solution and a single solvent as the heated solvent vapor, since the pressure of the heated solvent vapor is comfortably higher than normal pressure, so it is possible to operate the distiller as an evaporator. Imparting a portion of the ability is easy and easily implementable. Furthermore, in this case, it is a preferred embodiment to provide a solvent recovery step in the drying step of the resin solution-impregnated base material and to use the overhead gas from the distiller in this step as heated solvent vapor.

〔Example〕

The present invention will be explained in detail below.

Study Example 1 In the flow shown in FIG. 1, the amount of solvent vapor flowing into the condensing chamber A and the amount of solvent vapor flowing into the decompression chamber B were studied.

First, the minimum pressure for the heated solvent vapor to move to the condensation chamber A is the moving speed of the base material of 30 m/min = 0.5 m.
/sec, when the solvent is methyl ethyl ketone (=MEK), the lower limit of the pressure difference (ΔP) for the solvent vapor to move against the movement of the base material is calculated from the following formula, ΔP
” 4X10-6ata.

■ ・ (20g book △P/r)" From the second result, it is possible to substantially prevent air from flowing into the decompression chamber by creating a slightly pressurized state. Therefore, the heated solvent vapor condenses. It can be seen that it is extremely easy to reduce the amount of air flowing into the chamber to the necessary minimum by combining it with a seal roll and to remove air almost completely from the base material.

Then, an outflow of MEK gas into the vacuum chamber is also easily produced. Solvent to MEK (M=72.11>, pressure (PL)
1ata steam, vacuum chamber pressure (P2) 0.23
3 ata, the thickness of the base material is 0.2 mm, the width of the base material is 1050 mm, and when the void ratio is 0.5, the inflow amount G of the solvent vapor into the decompression chamber has approximately the same cross-sectional area. It can be treated in the same way as the flow rate passing through an orifice. As a result, the inflow amount G is calculated by the following formula.

G=μ＊'! , * alI * Pi / (R book Tl)
μ in the formula: runoff coefficient G = 74.06 kg/h (1, Q3 kgmol/h
, or 23.0 Nm'/h).

This vapor is recycled by being condensed and evaporated by heating and cooling. The amount of heat is the latent heat of vaporization of MEK (
410kcal/kg) and 8.1910'kcal/
It is h. If this is converted into steam or cooling water, it is 0.
．． 0157 Ton/h, cooling water amount 0.819 To
n/h.

Furthermore, MEK per meter of base material carried into the resin liquid tank
The amount (well, 1.05 pieces 10-' X (1,549 pieces 0
．． 233) -0,0379g or less, which is a negligible amount.

Also, for comparison, when considering the case of the conventional vacuum impregnation method, assuming that pressure reduction to 10 mmHg = 0.013 ata is essential, in the above, a,: -7,35 pieces 10-
'm', G = 51.79 kg/h, (1,7
85 gmol/h, or 33.4 Nm'/h)
becomes.

[Operation and effects of the invention]

As is clear from the above detailed description of the invention and study examples, according to the prepreg manufacturing method of the present invention, air is substantially removed by heated solvent vapor. It is possible to extremely reduce the burden of vacuum suction and exhaust gas treatment.

In addition, there is no problem of changes in the concentration of the resin solution due to the mixing of a solvent into the resin solution as in the solvent pre-impregnation method, and variations in the amount of resin adhered to the substrate due to this.

In addition, the prepreg obtained is equivalent to or better than that obtained by vacuum impregnation method, which maintains a high degree of reduced pressure, so its industrial significance is extremely high.

[Brief explanation of the drawing]

FIGS. 1 and 2 are schematic diagrams of an impregnating apparatus which is the main part of the prepreg manufacturing method of the present invention. Numbers and symbols in the figure are A: Condensation chamber, B: Decompression chamber, C: Resin solution tank, D: Heating solvent vapor chamber, 10: Base material, 11: Solvent vapor displacement base material, 12: Solvent vapor removal base material , 13: each shows a resin-impregnated base material. Patent applicant Mitsubishi Gas Chemical Co., Ltd. agent (907
0) Patent Attorney Sadafumi Kobori 1st Figure Vacuum Pump Flit Solvent J

Claims (1)

[Claims] 1. A prepreg manufacturing method in which a base material is impregnated with a resin liquid and dried by heating, in which the base material is passed through heated solvent vapor to substantially replace air with solvent vapor, and then the pressure is reduced. A method for producing prepreg, which comprises introducing the prepreg into a chamber and removing a portion of residual air and solvent vapor under reduced pressure, and immediately impregnating it with a resin liquid. 2. The prepreg manufacturing method according to claim 1, wherein the heated steam is the same solvent as the resin liquid. 3. The prepreg manufacturing method according to claim 1, wherein the resin liquid is a solvent-free resin liquid. 4 Solvent condensation chamber [A] equipped with a cooler, the solvent condensation chamber A
A heated solvent vapor chamber [D] adjacent to the inlet and outlet of which is sealed by a roll and equipped with a heater, said heated solvent vapor chamber D
A decompression chamber [B] whose inlet and outlet are sealed by rolls, and a resin liquid tank [C] which is directly connected to the outlet roll of the decompression chamber B and whose entire surface is filled with resin liquid.
] The method for producing a prepreg according to claim 1, wherein an impregnating device having at least the following is used.