JPS5962111A - Preparation of prepreg - Google Patents

Abstract

PURPOSE:To obtain a prepreg which is almost free from moisture, evenly impregnated with resin and suitable for preparing a paper substrate copper plated laminated board, etc. excellent in electric insulating capacity by such an arrangement wherein a cellulose substrate impregnated with resin solution is heated by microwave under hot moisture atmosphere and then it is dried. CONSTITUTION:A resin impregnated substrate 2 is prepared by passing a substrate 1 through a resin solution tank 11 and it is sent to a hot moisture microwave processing chamber 13 through squeeze rolls 12 and microwave heated under hot moisture atmosphere (preferably under heated hot moisture atmosphere of which relative humidity is 100%), and then sent to a drying machine 16 and dried there, and the titled prepreg (preferably resin content is 10-60wt%) is thus obtained. As said substrate, a kind of kraft paper, e.g., is used and as a resin solution, e.g., a solution wherein preferably 60-100wt% of phenol resin are dissolved in a solvent such as water, etc. is used.

Description

Detailed Description of the Invention This investigation relates to a prepreg manufacturing method. Since the laminate is made of prepreg, which is a cellulose base material impregnated with a resin liquid, moisture that impairs electrical insulation is removed from the prepreg before the laminate is manufactured.

That is, the moisture in the pulley preg is removed by heating the prepreg with hot air, steam, electric heat, or the like. However, the moisture in this prepreg is due to the moisture contained in the cellulose base material.
Because the cellulose base material itself is highly hydrophilic, it cannot be easily removed by the external heating method described above. Furthermore, when the temperature is as high as 130° C. or higher, a keratinization phenomenon occurs and the base material becomes brittle. Furthermore, according to the external heating method, the impregnated resin of the prepreg is cured first, so there is a limit to how much water can be removed. Therefore, the obtained laminate had a problem in electrical insulation (particularly electrical insulation after cooking). It has been considered to use a thin cellulose base material, but this also results in poor productivity and increased costs, so this also requires some time.

Therefore, as a result of repeated research to solve these problems, the inventor developed a method of applying microwave heating in a moist heat atmosphere to a resin-impregnated base material (prepreg), which is a cellulose base material impregnated with a resin liquid. They discovered that the desired purpose could be achieved by drying the product after application, and arrived at this invention.

That is, the gist of this invention is to apply microwave heating in a moist heat atmosphere to a resin-impregnated base material obtained by impregnating a cellulose base material with a resin liquid, and then dry it.

It is believed that the reason why this invention provides good results is as follows. In other words, by heating the resin-impregnated base material (prepreg) with microwaves, water fleas in the cellulose base material are selectively heated (internal heating).
It is vaporized and discharged to the outside, which causes the internal structure to become coarse, and when this is cooled by stopping microwave heating, the internal pressure is reduced, and the surface side of the cellulose base material is then dried. The resin has migrated into the interior, and the prepreg is now uniformly impregnated with resin with almost no moisture.
It is thought that it will become possible to use I. By performing microwave heating in a moist heat atmosphere, it becomes possible to achieve a uniform distribution of microwaves and a cooling prevention effect due to convection, thereby further improving the effectiveness of microwave heating.

Next, this invention will be explained in detail.

Examples of the cellulose base material used in this invention include base materials containing cellulose such as kraft paper, cotton linter paper, patterned paper, and plain woven cotton cloth. As a resin liquid,
Examples include phenol resins (water-soluble resol resins), amine resins (area, melamine), unsaturated polyester resins, or epoxy resins dissolved in a suitable solvent.

Even if no particular solvent is added, the resin may contain a monomer and the monomer may serve as a solvent. Any resin that exhibits a liquid state can be used as is. Note that the above-mentioned solvents include those containing water, methanol, ethanol, acetone, or methyl ethyl ketone as a main component. In some cases, two or more of these solvents may be mixed.

The concentration of the resin liquid is 60 to 10100 N% (hereinafter abbreviated as "chi") for non-volatile content (resin content) for enol resins and amino resins, and 70 to 100% for epoxy resins.
Although it is possible to achieve sufficient impregnation even if the amount is 70% to 90%, it is practically preferable. However, the concentration of the resin liquid is not limited to this range, and it goes without saying that a resin liquid with a lower error rate than this, such as [+11%] of about 40%, can be used.

The method of impregnating the base material with resin is the roll coater method,
Various methods such as dipping and brush coating can be used. Regarding the application of the resin liquid, the resin liquid may be applied to only one side of the base material, or may be applied to both sides. The resin liquid to be impregnated into the base material is preferably in a range such that the resin content of the prepreg after drying is 10 to 60%.The microwave heating of the prepreg in a moist heat atmosphere can be performed using a known microwave heating device. The heating is carried out in a moist heat atmosphere, for example, in a heated atmosphere with a relative humidity of 10t1%. Heating time depends on the type of resin liquid, magnetism,
It is selected appropriately depending on the thickness of the base material.

Tests are conducted in advance to select the most suitable time. In this case, microwave heating directly heats only the moisture inside the inn, so the heating time is 1/l compared to normal external heating.
O~1. It can be shortened to /100. That is, the temperature of the resin of the prepreg does not rise, but only the temperature of the water rises, vaporizes, and evaporates from the surface of the prepreg. Due to this transpiration, the internal structure of the cellulose base material becomes coarse due to the evaporation of water. A moist heat atmosphere improves the efficiency of this microwave heating. Drying after microwave heating is usually performed using a known hot air dryer. During this hot air drying, the inside of the cellulose base material becomes lower than during microwave heating, and is in a cooled state, so the inside of the base material is in a reduced pressure state, and the impregnated resin on the surface side becomes rough inside. Penetrates the part of the body. As a result, a prepreg with almost no moisture and uniformly impregnated with resin can be obtained.

FIG. 1 shows an embodiment of an apparatus used for the manufacturing method according to the present invention. In the figure, a base material l such as roll vapor that has passed through a resin liquid 4w11 becomes a resin-impregnated base material 2, and is sent to a moist heat microwave processing chamber 13 via a squeeze roll 12. Warmed moist air is held in this chamber 13, and the resin-impregnated base material 2 is subjected to microwave heating in a moist heat atmosphere. In this case, the humidity of the moist heat microwave processing chamber 13 is set to 100% RH. Microwave heating may be performed while directly applying heated steam to the resin-impregnated base material.

By microwave heating in this moist heat atmosphere, only the moisture in the base material can be selectively heated and expelled from the base material while preventing the impregnated resin in the resin-impregnated base material from drying. Then, the resin-impregnated base material 2 that has left the wet heat microwave treatment chamber 13 is sent to a dryer 16, dried, and then comes out of the dryer 16. In the figure, 15 is a microwave oscillator, 17 is a steam heating Erofin for heating the air taken into the dryer 16, and 18 is a sushi air duct.

Next, the practical implementation will be discussed together with the comparative example 111' and the conventional example.

[Example, comparative example and conventional example]

A resin with the following formulation was prepared.

(Resin A) Brominated epoxy resin (Ebikuron 153 manufactured by Dainippon Ink Chemical Industries, Ltd.) 27 g
Arashi part (hereinafter abbreviated as "r part") Chain epoxy resin (Epicron 1600 manufactured by Dainippon Ink and Chemicals) lo
part hardener paravinylphenol lo part accelerator
Benzyldimethylamine 0.005 part (#i
, l fat B) Hisphenol Am solid epoxy resin (epoxy m475) 70 parts Epoxy resin (engineering boxy part 180) 18 parts Hardening agent Dicyandiamide 4 parts Promoting agent Benzyldimethylamine 0.1 m (Resin C) Bisphenol A type epoxy resin (Epicote 828) 37 parts Curing agent Paravinylphenol 10 parts Accelerator Penzyldimethylaquine 0.005 parts (Resin D) Add phenol 940j to a flask equipped with a stirrer, thermometer, and condenser. ' (equivalent to 10 moles), 470f of tung oil, and 1.759f of para-toluenesulfonic acid were added and mixed with stirring.

Heat this mixture with stirring and after about 40 minutes
℃ and then refluxed for 30 minutes. After refluxing, the mixture was immediately cooled down to room temperature in about 30 minutes. To this, 37% formaldehyde 1095F (formaldehyde 13.
5 mol of ammonia) and 27.29 mol of 25% ammonia water (corresponding to 0.4 mol of ammonia) were added thereto and thoroughly stirred and mixed. The mixture was heated with continued stirring to boiling for about 30 minutes and then refluxed for 60 minutes. Immediately after the reflux was completed, the internal pressure inside the flask was reduced to 100 to 150 μHg, and dehydration was carried out under reduced pressure while continuing heating to obtain a resin. The resin content of the obtained resin was 87%.

(Ji Ha”) Ky7lene formaldehyde resin (molecule Jt450) 1
70 (Hl, phenol 850f, para-toluene sulfone) 4. Oy was placed in a four-bottle flask equipped with a stirring rod and a condenser, heated to 100-105°C, reacted for 30 minutes, and then further reacted for 120 minutes while dehydrating. This was cooled to 40" IC, paraformaldehyde 3309. triethylamine 5.2 F and 800 g of toluene were added as a solvent, and the mixture was reacted at 90° C. for 150 minutes. Then, it was concentrated under reduced pressure to obtain a solution containing toluene containing ft20%,
A resin with a resin content of 70% was obtained.

(Resin F) In a four-loaf flask equipped with a stirrer and a condenser, 7 e/-
94Of (equivalent to 10-T-l), 80% formaldehyde 488F (equivalent to 13 moles of formaldehyde)
, aniline 15M (equivalent to 0.16 mol) and triethylamine 10. I F (equivalent to 0.1 mol) was reacted at 100° C. for 90 minutes to obtain an aniline-modified resol resin. The resin content of this resin was 73%.

(Resin G) In a fourth flask equipped with a stirrer and a condenser, 940 g of phenol (equivalent to 10 mol), 55% formaldehyde 655F (equivalent to 12 mol of formaldehyde) and triethylamine 101f (equivalent to 0.01 mol) as a catalyst were added. ), refluxed with a knife for 45 minutes at J'C
Saze, I got the other side of Resol. The resin content was 63%.Example resin A was diluted with methyl ethyl ketone to obtain a resin content of 75%.
% resin liquid. As a base material, density 0.52y/an
r* A resin-impregnated base material using 10 mils (2544B) cotton linter paper and dip-coated with the resin solution was heated in a microwave (5 KW) at 2450 Mllz in steam at 100°C (100% RH). Processed for 5 seconds. After that, hot air drying is carried out, and the resin kanyu h15
Prepregs of 0 to 51 inches were obtained.

[Execution [Nri 2]] Resin B was diluted with acetone to obtain a resin liquid having a shoulder content of 85 cm. Other than using this resin liquid as the resin liquid,
After processing under the same conditions as in Example 1, it contained resin! 1j
', I obtained 50-51 prepregs.

[Actual strength or fren 3] Resin C was mixed with resin liquid (5 ml) without adding any other thickening agent.
It was coated by dip coating on cotton linter paper of 08 μm) and then irradiated with microwave (5 KW) of 24 soM Obtained.

[Example 4] A resin solution was diluted with methanol to obtain a resin solution with a resin content of 50%. As a base material, the density is 0.51 f/cd.

A kraft base paper having a thickness of 20 mils (508 μrrL) was coated with the resin liquid by dip coating, and then water vapor at 100° C. was sprayed on the paper and then microwaved at 245 QMHz (5 KW) was irradiated for 5 seconds. [After 2 hours, hot air drying was performed to obtain a prepreg with a resin content of 49 to 50%.

[Implementation f! I 5 ] The resin solution was diluted with methanol to obtain a resin solution with a resin content of 65%. As base material 2, density 0.45 y7csi
.

Using kraft base paper with a thickness of 30 mils (762 μrrL), the resin solution was applied by dip coating, and then 2450 MHz microwave (5 KW) was irradiated for 5 seconds while blowing 100°C steam. Afterwards, drying was performed using a Hatake frequency heating device to obtain resin-containing M, 50-51.
I got the prepreg of Chi.

[Example 6] The resin liquid used in Example 5 had a density of 0.65 f/cd.
, coated on one side of kraft paper with a thickness of 13 mils (33 ottgl), then sprayed with steam at 100°C and heated with microwave (5 KW) at a power of 2450 + 4111.
) was irradiated for 10 seconds. Thereafter, hot air drying was performed to obtain a prepreg containing 48 to 50% resin gold.

Example resin 1) was diluted with methanol to obtain a resin liquid with a resin content of 75%. As a base material, dense MO, 68 f/d.

A kraft base paper with a thickness of 20 mils (508 μm) was used, and the material was treated under the same conditions as in Example 4 to remove a resin gold + 4' j + i: 49-50% prepreg.

Example resin 1) was diluted with methanol to obtain a resin liquid with a resin content of 80%. As a base material, density 0.51 f/cti
.

Using kraft base paper with a thickness of 10 mils (254 μrIL), the resin solution was applied by dip coating 12 at 100°C.
2450 A4) lx microwave (5 KW) was irradiated for 5 seconds. Thereafter, it was dried with hot air to obtain a prepreg with a resin content of 49%.

Example Resin E was used as the kneaded resin liquid. The pond was treated under the same conditions as in Example 8 to obtain prepreg.

[Implementation Framework 10] Resin G was used as it was as a resin liquid. The base material has a density of 0.47 f/cd and a thickness of 10 mils (254 μr).
Using a cotton linter paper (rL), soak it with the resin solution and apply it for 10 minutes. Then, while blowing 100℃ water vapor, 2450% 4Hz microwave (5KW) was applied for 10 minutes.
Irradiated for seconds. Afterwards, it is dried with hot air, and the resin-containing shoulder rack 46
% prepreg was obtained.

[Example 11] Resin F was diluted with methanol to obtain a resin liquid with a resin content of 70%. Then, using a plain-woven cotton cloth as a base material, the resin liquid was dip-coated onto it, and then microwaved at 2450 MHz (5 KW) was applied for 1 hour in a steam atmosphere at 100°C.
It was irradiated for 5 seconds. After that, it is dried with hot air and the resin content is 5.
A 0% prepreg was obtained.

[Example 12] A resin solution was diluted with methanol to obtain a resin solution with a resin content of 65%. And as a base material, density 0.51f/cd
, ) Using 10 mils (254 μnL) W-milled kraft paper, the resin solution was dip-coated onto it, and then,
The coating substrate was introduced into a room with a temperature of 80°C and a relative humidity of 50% by blowing out water vapor, and a 2450MHz microwave (5K
W) was irradiated for 10 seconds. Thereafter, hot air drying was performed to obtain a prepreg with a resin content of 49 inches.

[Act 7 + Tii I41113] The above actual case ξ except that the conditions of the steam treatment 441 were that the treatment was carried out for 5 seconds indoors at a temperature of 60 °C and a relative humidity of 30 °C.
A prepreg was obtained by processing under the same conditions as in Example 12.

[Comparative Examples 1 to 11] In actual M+j VIJ 1 to 11, the same manufacturing conditions as those of the corresponding numbered implementation β and ri were used, but moist heat microwave treatment was performed, and after applying the resin liquid. Drying was performed immediately.

[Conventional Reli 1] Resin A was diluted with methyl ethyl ketone to a resin content of 6.
It was made into a 5% resin liquid. This has a density of 0.52'I/d
The prepreg was coated at t=l-Ut on cotton linter paper having a thickness of 10 mils (254 .mu.rrL) and then dried to obtain a prepreg with a resin content of 50 to 51%.

[Conventional Example 2] A resin solution was diluted with methanol to obtain a resin solution with a resin content of 5°. This was applied by dip coating onto kraft paper with a density of 0.50 f/c4 and a thickness of 10 mils (254 μrrL), and then dried with hot air to obtain a resin content of 49 to 50
% prepreg was obtained.

(Manufacture of M-layer board) A predetermined number of prepregs obtained in each of the Examples, Comparative Examples, and Conventional Examples were superimposed, and one adhesive-coated copper foil (35 μm thick) was added from each of the seven prepregs. East, gold 1
The product, a single-sided copper laminate, was produced by sandwiching it between plates and heat-forming it using a conventional method. The production conditions are the 16th im l
It was y.

(sex song) Table 2 shows the performance of the single-sided cap laminate plate.

(1,000 margins) <'i'+ 1 From Table 2, it can be seen that the actual Am (s41 product has superior performance compared to the comparative product and the conventional example product.

As described above, the present invention is characterized in that a 4MJ fat-impregnated base made by impregnating a cellulose base with a resin liquid is subjected to microwave heating in a moist heat atmosphere and then dried. #1 moisture content without increasing costs
It is possible to prepare a prepreg (11) from which the resin has been completely removed and the resin is uniformly impregnated.

[Brief explanation of the drawing]

! Figure 1 shows the equipment used to carry out this invention b9. FIG. 1...Left hand 2-Resin-impregnated base material 12...Squeeze roll 13...Heat microwave treatment chamber 15...
Microwave oscillator +′? , 16... Dryer 17.
...Steam heating Erofin 18...Exhaust duct agent Patent attorney Takehiko Matsuki 1 Figure 1

Claims (2)

[Claims] (1) A prepreg manufacturing method characterized by subjecting a resin-impregnated base material, which is a cellulose base material impregnated with a resin liquid, to microwave heating in a moist heat atmosphere, and then drying the resin-impregnated base material. (2) The method for producing a plastic knob according to claim 1, wherein the moist heat atmosphere is a heated steam atmosphere with a relative humidity of 100%.