JPS5926210A - Method for impregnating synthetic resin - Google Patents

Abstract

PURPOSE:To minimize generation and residue of voids, by a method wherein after a decompressed and defoamed synthetic resin is poured into a material to be impregnated under reduced pressure, the pressure is raised back to a normal pressure, and after decompressed again, it is raised back to a normal pressure and this process is repeated at least once. CONSTITUTION:Seven sheets of polyester non-woven cloth H-8010, 10cmX10cm manufactured by Japan Vilene Co., Ltd. are used in a state of piling-up as a material 3 to be impregnated. After the inside of a vacuum tank 1 is decompressed to degass the air contained in the material to be impregnated, an impregnated synthetic resin 4 is agitated and defoamed by a hopper. After the synthetic resin 4 is gradually poured into an impregnating tub 2 from its bottom until the material 3 to be impregnated is completely covered with, the inside of the vacuum pressure tank 1 is raised back to a normal pressure (1 atmospheric pressure). After decompressed by way of the same condition and procedure as mentioned above, it is raised back to a normal pressure. This process is repeated. By this method, the number of inevitably generating void can be minimized.

Description

[Detailed description of the invention] This invention relates to a method for impregnating synthetic resin,
More specifically, for example, a coil body of an induction electric device or the like is used as an object to be impregnated, and after injecting degassed epoxy (such as 1R1 resin) into the object under reduced pressure,
This invention relates to a method for impregnating a synthetic resin by returning the pressure to normal pressure and impregnating the object with the synthetic resin.

The conventional impregnation method of this type will be explained below. The coil body, which is the object to be impregnated, is stored in an impregnation tank, and the impregnation tank is stored in a vacuum pressurized tank2.Synthetic resins such as epoxy resin are stored in a mixing device (hereinafter referred to as The synthetic resin is injected into the impregnating tank in the vacuum pressurized tank under reduced pressure (x stirring and degassing. To explain this in more detail, first, the material to be impregnated is placed in an impregnating tank and stored in an IC air pressurized tank.Next, the lid of the vacuum pressurized tank is closed, and then the vacuum pressurized tank is removed. Reduce the pressure inside the tank and apply vacuum (forced by the material to be impregnated)
The air and moisture inside the coil (same as above) are discharged to the outside of the vacuum pressurized tank. Similarly, synthetic 464 fat is depressurized in the hopper and degassed by stirring. The degree of pressure reduction depends on the shape, size, and purpose of the object to be impregnated, but in general, it is approximately 3 m/m.
mHf~/θmtnHy culm degree. Next, the defoamed synthetic resin is passed through a pipe into an impregnating tank in a vacuum pressurized tank, where the material to be impregnated is completely immersed in Kfi, and 8-component resin is injected. After injecting the synthetic resin, close the pressure reducing valve and injection valve to return to normal pressure. After a predetermined time has elapsed, the soaking process is completed. The removal of the material to be impregnated after the impregnating process, the hardening process, etc. are not directly the object of the present invention. 1. When the material to be impregnated cannot be completely impregnated with +L'C, the fatal drawback is that of birds and ivy.I will explain and explain impregnation here, and show the reason for the drawback.The material to be impregnated is By reducing the pressure, the air in the object to be impregnated is expelled.The oil is returned to normal pressure by the volume of the air exhausted from the object to be impregnated. It is impregnated with air in a similar manner. However, in most impregnating operations, the object to be impregnated is often an insulating base material, such as polyethylene terephthalate, mica, a conductor, etc., wound around the main body. , due to the resistance of the base material, a-forming fat enters within 1.1 months, and K<<.

The purpose of pressurization in the conventional method is to promote the replacement of air initially released by depressurization with synthetic 11tt fat.

Therefore, increasing the pressure will cause the displacement rate to increase (i.e., the displacement rate will increase the rate of displacement) (i.e., 1ηi-J). void (
Synthesis (completely J with 01 fat)
It doesn't lead to Qi'L').ノ, rzef, ``Raba, air and synthesis ((I (on top of replacing fat,
Completely remove the air inside the object to be impregnated (actually, in addition to air, moisture and other generated gases can also be removed by 3 inches).

7. t (7, shape is completely true 4s shape k, 11, l, ←) cannot be obtained, and in many containing works, as mentioned above, /nm1lp~io Kui Kasumi Hq utilization 7), 121 can be submerged. 1. Now / t20 CC
The pressure of the container was reduced to 10mm 1Iy, about 8/Jcc
Since ancient times, there has been an air of
One point kT-this? ：j I feel like a void and the evening (Ji exists)
7, the electrical/I'S characteristics (for example, collapsing test results 1'll!, jnic Fi meeting) will result in an unfortunate result. Therefore, the pressure is high
l f7, J: M14 Shit/, J Cf2 air space l, r: (let, not only the volume decreases in proportion to the pressurizing force, but the final pressure is the same as the pressurizing force. When the air pressure inside the void increases, the contraction of the volume of the void ends.In most cases, after the pressurization ends, the pressure is returned to normal pressure and hardening is performed, so the pressure of the void is also normal pressure and the volume is up to /JCC. Expanding.

As described above, according to the conventional impregnation method, it is impossible to completely exhaust the air (including moisture and other generated gases) in the vacuum pressurized tank, that is, in the object to be impregnated (in a completely vacuum state). (unless it is possible to do so) there will always be a void and the result will be 91. c gal. The location and number of voids are influenced by the density distribution of the base material that makes up the impregnated material; in many cases, voids tend to remain concentrated at one point. Therefore, in today's induction electric 4D devices and the like which require higher level electrical characteristics, the occurrence of voids is a fatal drawback.

This invention was made in order to eliminate the drawbacks of the above-mentioned conventional methods, and aims to provide a synthetic resin impregnation method that minimizes the generation of voids and has excellent electrical properties. (voice).

As a result of intensive research, the inventors discovered the following 711 fruits.

Understood. That is, after reducing the Ilν impregnated material under reduced pressure and depressurizing it, the plastic resin is injected, and then the pressure is returned to normal pressure.
? '＞2Reducing the volume of voids generated by the synthetic resin impregnation method of impregnating an object with synthetic resinj), or microvoids3, u, +, An embodiment of this invention i# Unique using drawings Explanation -→ru. Fig. 1 is an explanatory diagram of impregnation showing an embodiment of the present invention, in which an object to be impregnated 3 is housed in a soaking tank λ in a glass tank 1, and the leached synthetic resin is inhabited. The status 1, I] indicates the internal pressure of the material J to be impregnated which is required for one kidney as explained below, and p't indicates the external pressure. Impregnation tank a and the object to be impregnated? 'tl'? Explaining the formation using P, 1% j diagram 6 Tate' diagram (a)
In the above, the impregnated culm v, 2 is formed by a sonorous plate, and the impregnated object 3 is a glass for spacer (/ (7 cm
X/0Crn)2/Fill the appropriate size through the rubber gasket l-,,! , 2 describes the role of cushion interest as 11 (
Sleeping. Therefore, it is possible to reduce the impregnated material, 7 to H: +
, +J ability, 1-)z is on. Impregnated material? Polyester non-1tc cloth H-gOlo manufactured by Nippon Vilene, 1
I used 7 pieces of 0crrr×/θω. No. 1,
Figure 7(b) shows this configuration viewed from the front, with the object to be impregnated 3.
Glass for spacer, 2/tozu jt 7': C is set so that it is raised above the bottom of the impregnating tank λ. When the synthetic resin for this impregnation is increased in size (☆1), the fat impregnates from around the flannel impregnated material J).

Next, the impregnation process will be explained in line '1. 'c'). Impregnated T Mu (
'1 Thoroughly expunge the inside of the vacuum tank 1 and remove the air inside the encapsulated container 3 by 14, as shown in the figure below. After compatibility defoaming of l,
Slowly start pouring from the bottom of the impregnating tank λ to the impregnated material.
? Pour until completely covered. Then, return the inside of the vacuum tank to normal pressure (/ATM). Step 1 (Straw, N, pressure → injection → normal pressure) is the 5th impregnation process.In the walk-in impregnation process, after this, the inside of the vacuum tank is constantly heated to 11・VC4.
) How to help L [end the process, but in this example decrease 1:E-)
After injection → normal pressure, add 1F → normal 1] 2 → steps 3
The oil work was carried out, and the state of impregnation was recorded by scanning the area in parallel with the passage of time. Therefore, the impregnation process and its results will be explained below.

Object to be impregnated made of the above nonwoven fabric, 7, that is, H-gθ1
0゜10α+X/(Actually measured average thickness of 7 cm x 7 sheets is i
A, 7 F+! Power in 1) Tsuta. When this was set in the impregnation tank 2, it was strongly compressed to a thickness between Ito and Ito. Actual average depth of impregnated object J'7.0
．． 1ggf, specific gravity using iJA. Also, the vacuum L during depressurization (1: is the average force of 9 ram Hy ('gauge pressure))]
Ivy.

FIG. 7 shows a simplified diagram for explaining the state of the impregnation process. In the same figure: F6, a is the vacuum tank/inside 2
・The state is shown immediately after the impregnation synthetic resin V is injected into the impregnation tank U.At this time, the inner JT:P and the outer pressure V are the same pressure, and from this, the n impregnation synthetic resin Impregnation of V begins. However, at this point, the internal pressure P = external pressure P'
Therefore, as shown in FIG. 6(b), even after several minutes have elapsed, the impregnating synthetic resin l remains at the level of capillary action, and the amount of the synthetic resin infiltrating is small. After that, in the process of pressurizing the inside of the vacuum tank, the internal pressure P and external pressure P' become p <p', and due to the pressure difference, impregnation of the synthetic resin for impregnation begins rapidly, and the pressure difference between the internal pressure P and external pressure P' becomes small. As the pressure increases, the infiltration speed slows down, and after a few minutes after returning to normal pressure, the internal pressure P = external pressure P', and the infiltration of the impregnating synthetic resin l is completed, leaving a central void 3/, which is the same as the conventional impregnation method.・Next, reduce pressure and normal pressure again! Again, a few seconds after the completion of depressurization again, the internal pressure P>external pressure P', and the central void, 7/, which is at normal pressure, starts to diffuse when the differential pressure with the external pressure P' becomes zero, and the same occurs. As shown in FIG.
The reduced pressure and center void 3/
The number of diffusion voids J,2 increases in proportion to the pressure difference with the internal pressure, and the volume of the central void 31 decreases. Same figure (d)
, (e) follows the time course of diffusion void 3.2,
(d) is a few seconds after the completion of decompression, and tel is the diffusion void at the time when several minutes have passed since then? This figure shows the state of λ, as the diffusion void 32 moves and diffuses over time and becomes
You can control the situation you are in.

As a result of repeating the process above, the reduction IF → normal 1F after the initial temperature and pressure of the bow → injection → normal pressure 1′), the central void 3/iμ
The diameter gradually became smaller than the diameter of the central bolt 3/ when the initial reduction F1→injection→normal IJ' occurred.

The first immersion process explained and illustrated in the above examples, namely, the depressurization (
In reality, the pressure is reduced once after the residents are in the room, and then returned to normal pressure. Yotsu1 Stable center point/f at normal pressure? I succeeded in taking a photograph of /, -Also, after normal pressure, the pressure was returned to normal at the stage of decompression, and the center void at this time (void of pressurized rη), 7
/ was also photographed.

To explain this photograph in detail, the central void 3/
The IF force in the central void, 7/, is equal to normal pressure,
The diameter of the central void 3/ decreases.However, since the pressure is reduced again after this, the pressure is returned to normal pressure once and the diameter of the central void 3/ is reduced.
Photographs were taken when the pressure inside the tank reached 7E (the expansion of the void had finished (stable)). Center void after returning to normal pressure? / becomes smaller (the dyed synthetic resin for impregnation shapes the link cuff of the void), but when the pressure is returned to normal, the center void J/ expands and one link cuff of the center void 3/ becomes visible. The inside of the inner link cuff has no A171 fat attached to it, so it is white in color, but the outer link cuff has a low resin density, so although it has 4j7.7 fat attached, it looks penta-colored. The outer part of the outer link cuff has a high 1δj fat density, so it has a dark color. Therefore, the diameter of the central void when photographing is possible and when the pressure is applied at 2ρG.

compared. As a result, the difference between the two could not be erased,
It was found that K is effective because the pressure increases the impregnation rate, but the effect of reducing voids is small/difficult.

The diameter of the central void 3/ at normal pressure is l' at the initial normal pressure.
12 days ago, about kma at normal pressure again, λth time J.

3rd time 1, 'r 111111, Fth time &maQ
A section, 1' /, (Tsl 0) Here, comparing the volume of the void at the initial normal pressure 'tt: and r#j diameter with the side cut value, impregnated material 3: polyester nonwoven fabric / θα × Measured average thickness of 10 sheets x 7 sheets: 1AJTrlTA Reduced thickness: 1=11.Order (forced compression) Measured average weight -ff1::W='ZθJglft Specific gravity: d==t J t.

Hei 1 Chaos 1J: Power: P-9 朋■(The apparent rest fiVl that looks at three spaces is V r --/ OX / OX O,/
4 = / A CC true volume ■yuke■, =w=-2o-jin-gg, medium j: / g CCd
iJ, A -srt(volume of space not including dimension V, 7 digits V,? = 1
1t -V, 2----/A-ta l agency τ10Kλcc The void rate η is injected with demu Hy and placed under normal pressure. The volume of void generated Vf is void width = reduced thickness = /6 city, therefore the void diameter Dl
Since V=-D't, the diameter of the void containing the V crystalline phase is 100 η, which is the actual value of 7. It is close to u2α, and it can be seen that there is no error in this example.

In the above examples, the occurrence of impregnation and diffusion voids is caused by the internal pressure P
It was found that the diffusion void J,20 is generated due to the differential pressure between As a result of investigating the differences in occurrence, we came to the conclusion as shown in Figure V. I 1, V
The figure shows a diffusion void J with a speed of 1x.
Figure 2 shows the difference between the two. (a) shows the decompression speed (time) for 03 minutes, and (b) shows the result for 22 minutes. If the decompression speed was done impulsively, the difference in JL. Central bojf to change,? A part of / is radially divided by P, IL, and when the decompression rate is slow, one side changes slowly, and the expanded void becomes buoyant and becomes a relatively large diffused void, 7.2. Is it central boiling? Translocate upward several times per 12 hours. 1iT'] In normal impregnation work, -C is also at normal pressure [■ After completion, the specified area 41J: Reduction LT at 1iT' when the force is reached, 1 fruitful, central void, 7
The advantage of dispersing / as a small void is the power.

Next, we investigated whether the impregnation method according to the present invention affects the electrical jl+ by using an induction coil.
Partial discharge initiation type J after impregnation was measured by applying the example.・5th
The figure shows the relationship between various impregnation treatment methods and partial discharge inception voltage. According to the figure, it is clearly understood that repeating the cycle from reduced pressure to normal pressure as in the present invention results in less variation in characteristics, and moreover, a higher level of characteristics can be obtained. As a result of these experiments, the pressure reduction was determined by the pressure reduction capacity of the vacuum bonder and the working time (equipment exclusive time).
~/! It is considered appropriate to perform this within the range of wHy (
/ When the temperature is below H2, the void becomes too large and difficult to process). Further, according to this embodiment, the ideal pressure reduction time (transition time) is within 30 seconds; if the time is longer than that, the diffusion force of the voids will be weakened and the effect will be weakened.

As explained in detail above, according to the present invention, in addition to the conventional impregnation method of reducing pressure → injection → normal pressure, by repeating reduced pressure and normal pressure again, the voids that inevitably occur can be minimized. It can be done. In addition, the generated voids can be diffused into minute voids and have less influence on electrical characteristics.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of an apparatus for explaining an embodiment of the present invention, FIG. b+
+ (C1゜(d) and (e) are simplified diagrams sequentially showing the states of the impregnation process, Figures ψ (al, (b)
Similarly, FIG. /...Vacuum tank, λ...Impregnation tank, 3...Object to be impregnated, l
・・Synthetic resin, glass plate for spacer 1.2.2・
・Rubber gasket. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Shin Kuzuno - Leather Figure 1 (b)

Claims (1)

[Claims] (1) In a synthetic resin impregnation method in which a synthetic resin defoamed under reduced pressure is injected into an object to be impregnated under reduced pressure, the pressure is returned to normal pressure, and the pressure difference at this time is used to impregnate the object with the synthetic resin.
A method for impregnating a synthetic resin, which comprises returning the pressure to normal pressure, reducing the pressure again, and returning to normal pressure, repeating the process at least seven times. (v) The method for impregnating a synthetic resin according to claim 1, wherein the pressure reduction is carried out within the range of /ShoH. (,7) When repeating reduced pressure and normal pressure, the transition time until reaching the predetermined reduced pressure after the predetermined normal pressure time is 70 seconds υ is impregnated with the synthetic resin according to claim 7. Method.