DE1960255B2 - PROCESS FOR MANUFACTURING INSULATING PAPER WITH LOW DIELECTRIC LOSS FACTOR - Google Patents

Description

mechanical strength. If z. B. the paper tape of low density helically wound on a conductor and then the paper-wrapped If the conductor is bent, wrinkles or tears will result in the wrapped paper.

As described by H. Stamm and M. K ah 1 e in "The improvement of the electrical properties of cable and capacitor paper" in the scientific journal of the Technische Hochschule Ilmenau, vol. 9 (1% 3), issue 5, p. 661 bis 666, published, there is also known another method in which paper is placed in a circuit of deionized water with a conductivity of 0.4 to 0.7 μS / cm between parallel electrodes to which a direct voltage is applied. The principle of this process consists in the use of the gradient of the ion concentration, based on the difference in the ion content between the papic and the deionized water that surrounds the paper. In this process, the greater the gradient of ion concentration, the greater the ion diffusion achieved, so that a large amount of low-conductivity deionized water must flow through the system and, moreover, it takes more than 1 hour to remove the remaining ions sufficient to remove. In this process, the application of the voltage only serves to accelerate the ion diffusion. In the literary magazine SCh. Kitajewa, WW Korolew, "Investigation of the Cellulose Electrodialysis Process" from "Bumasnaja Promyslennost" [Paper Industry] [6], pp. 4 to 7 [1957], describes that pulp was subjected to a treatment similar to that given above. However, this process takes 1 hour to reduce the ash content from 0.3 to 0.12% and is therefore unsuitable for industrial use. In addition, cellulose fiber treated in this way in the pulpy state is susceptible to renewed contamination by foreign materials, which increase the loss factor in the subsequent papermaking process.

The object of the present invention is to provide a method with which insulating paper in far less time than that of the above-mentioned methods at a satisfactorily reduced Loss factor can be produced.

This object of the invention is achieved in that the paper continuously through a liquid Medium with a conductivity of at least 10 11 S cm is moved and then dried will.

According to the invention, the paper can be treated using significantly reduced working hours will.

The paper treated according to the invention has excellent mechanical strength and can exposed to high voltage in high voltage equipment. Here is the loss factor in the insulating paper reduced evenly at every point, and the paper can be used without problems and economically Scale to be manufactured.

The principle of the treatment according to the invention to achieve a noticeable reduction in the The loss factor in a short time from a few seconds to 10 minutes has not yet been clarified. It however, it can be attributed to the fact that the paper has a higher electrical load is exposed. induced by the presence of liquid extraction medium with a conductivity of not less than 10 μ S / cm, so that soluble and hardly soluble ionic substances on the surface and inside the paper easily into ions separated and these ions will soon be extracted into the liquid extraction medium, and further the fact that that the paper continuously introduced into the electric field releases the ions into the liquid extraction medium releases to keep its conductivity at a higher level.

In this respect the invention differs considerably from the above-mentioned known methods, for example that of H. Stamm, which is a liquid with a lower ionic concentration used as deionized water (conductivity 0.4 to 0.7 μS / cm) to facilitate ion diffusion to accelerate, which results from the difference in the ion concentration.

According to the invention it is necessary that the liquid extraction medium located between the electrodes a conductivity "cm" has at least 10aS / cm. If the conductivity is lower is than 10μ S'cm, can only have poor extraction efficiency and the treatment required a long time, more than 1 hour, as in the method of H. Stamm. Even if the applied voltage is high, In this case, the extraction efficiency cannot be improved, nor can the time for the extraction be shortened. The higher the conductivity of the extraction medium located between the electrodes, the greater the effect of the ion extraction. Preferably, the conductivity of the liquid medium is not more than 300 μS / cm Though a liquid medium whose conductivity is higher than 300 μS cm can be used according to the invention can, the increase in conductivity da / u tends to increase power consumption and the generation of Accelerate heat and gases as a result of the electrolysis of water. That is why the conductivity lies preferably in the range from 20 to 300 μS cm. That liquid extraction medium with a conductivity of not less than 10 μ S / cm is available throughout Length of electrodes is present, but it is not necessary to have the medium on top of them Way to provide provided the liquid extraction medium has a conductivity of 10 μ S cm or higher is only filled between the electrodes over the effective length of the electrode. where is the effective length is represented by the following equation:

Effective length of the electrode in meters = V x f, where V is a pulling speed (m see) of the paper and r is the time (seconds) it takes to reduce the dissipation factor of the paper to be treated to the desired extent.

At the start of operation, the conductivity of the liquid medium to be used according to the invention is required does not necessarily have to be 10 μS cm or more, but it can also be a liquid medium with a: conductivity of less than 10 μ S / cm be used because soluble ionic substances are dissolved in the liquid medium of the paper, which is continuously introduced into the medium to increase the conductivity of the liquid Medium to achieve progressively. So if a nutritious medium with an original conductivity less than 10 μ S / cm is used, the continuous feeding of paper takes place in

the liquid medium with or without the application of voltage before the extraction process until its conductivity 10 μ S / cm is reached, and then the process of the invention is initiated. As a liquid extraction medium are water or aqueous solutions that contain various chemicals dissolved in it, economical and effective. The invention is particularly advantageous because they use industrial water can, which is cheap to get. In order to increase the conductivity of water, it will at least added one of the ionic substances which are soluble to dissociate into ions. The amount The correct selection of the ionic substances to be added enables the operator to adjust the conductivity of water to a suitable value. As ionic substances are preferred water-soluble salts of inorganic or organic acids can be used, provided they are exert no adverse influence on the paper to be treated and on the electrode. The preferred inorganic salts are ammonium, alkali and alkaline earth salts of inorganic acids, such as Hydrochloric acid, sulfuric acid, phosphoric acid, carbonic acid, etc. are preferable examples

NH ₄ Cl (NH _{4 I 2} SO ₄ , NH ₄ NO _3. NaNO. ,, NaCl,
Na ₂ SO ₄ , Na ₂ CO ₃ , NaHCO ₃ , KCl, K ₂ SO ₄ ,
K ₂ CO ₃ , KNO ₃ , CaCl ₂ , Ca (NO ₃ ) ₂ , MgCl ₂ ,
MgSO ₄ , Mg (NO ₃ J ₂ , Ba (NO ₃ J ₂ , BaCl ₂ etc.

The preferred salts of organic acids are ammonium, alkali and alkaline earth salts of various organic acids, such as acetic acid, oxalic acid, etc. Also usable are water-soluble complex salts and double salts of various metals, such as potassium chromium sulfate, etc. Other ionic substances, such as acid or alkali, can can also be added to the water in such an amount that the addition of acid or alkali does not have an undesirable effect on the quality of the paper to be treated and on the electrode. The acids to be added are organic or inorganic acids, but preference is given to inorganic acids such as, for example, hydrochloric acid, sulfuric acid, succinic acid, nitric acid, nitrous acid, and hydrocyanic acid. Carbonic acid, phosphoric acid, phosphorous acid, metaphosphoric acid, boric acid and chloric acid. Examples of the organic acids are carboxylic acids such as acetic acid, oxalic acid, etc., and amino acids. The alkali materials to be added include potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide, barium hydroxide and ammonium hydroxide, with calcium hydroxide and magnesium hydroxide being most preferred. It is also possible to use mixtures of water with water-soluble, non-ionic organic substances; Examples are various water-soluble organic substances such as monohydric alcohol, glycol, aldehyde, ketone, ketone alcohol, ether, ester and urea. The water-soluble non-ionic organic substances described are added to the water together with one or more ionic substances, as mentioned above. The amount of ionic substances to be added can be determined as a function of the desired conductivity of the liquid, but under all circumstances no addition should be made in an amount which impairs the quality of the paper and damages the electrode. As the paper to be treated according to the invention, insulating paper, which is produced by conventional methods and is known, is preferably used. Insulating paper is classified into a wide variety of types and grades, including column insulation paper, condenser tissue paper, high voltage capacitor paper, cable insulation paper, extra high voltage cable insulation paper, and the like. Papers of all of these types can be treated in accordance with the invention to look down dissipation factor. The method of the invention is preferably applied with advantage to conventional high-voltage insulating papers which have an apparent density of 0.5 to 1.3 g / cm ³ and an air resistance of at least ISO Gurley-sec / 100 cm ³ . The extra-high-voltage insulation paper with an apparent density of 0.55 to 0.95 g / cm ³ and an air resistance of 200 to 10000 cm ^{1 can} preferably be used. In addition, the invention can be applied to special insulating paper with improved electrical and mechanical properties, such as, for example: insulating paper coated with mica, described in T. Ya in amotor, M. Yamamoto, S. Na ka mot o and Y.Take, »Mica- Loaded Paper for EHV Power Cable ", Business Paper No. 69 TP 9 7-PWR, presented to the IEEE Winter Power Meeting, New York, NY January 26-31, 1969, combination insulation paper described in K. K o ji in a. H. Kub o and S. Mar uy a ma, "Development of Special Insulating Paper for EHV Power Cable," Business Paper No. 68 TP 64-PWR, submitted at the IEEE Winter Power Meeting, New York, NY, Jan. 28 through February 2, 1968. or insulating paper made on the multi-wire principle in which the layers of paper are brought together when wet and formed into a single sheet. However, the paper to be treated according to the present invention is not limited to the insulating papers mentioned above, but the present method is also applicable to paper.

that with regard to the electrical properties in particular the dissipation factor is too poor to be used as insulating paper. Such paper can also be used for Insulation purposes can be used after it has been treated by the method of the invention.

Furthermore, the invention is applicable to dried paper after it has been processed into sheets, as well as on undried paper, which is not thoroughly was dried or which was half-dried or undried. The by the present Method of treating paper type is selected depending on the purpose for which the insulating paper obtained is used.

The speed of the paper moving between the electrodes depends on the thickness, the Apparent density, the strength of the paper, the amount of ionic substances to be extracted from the paper, the applied voltage, the length of the electrodes, the conductivity and flow rate the liquid extraction medium and other conditions. However, the paper speed is in controlled in such a range that the paper is not subjected to excessive mechanical stress. It is in the range of 0.1 to 800 m / min, preferably 1 to 500 m / min, and more preferably im

Range from 10 to 300 m / min. The period of time for which the paper is exposed to electrical stress between exposure to electrodes (i.e. treatment time) depends on the above

Paper speed and the length of the electrodes. Desired results can usually be in some Seconds to 10 minutes can be reached. It is highly desirable to insert the paper so that the Paper surface faces the electrode surface, since the best extraction speed is in this position can be achieved, however, there is a slight slope, if any, relative to the electrode surface not to complain about.

preferably in the range from 0.5 to

m / min,

m / min. ,. ,.

In the case where the liquid extraction medium flows between the electrodes, it is done by electrolysis of the water generated hydrogen gas and oxygen gas from the space between the electrodes in the form of small bubbles along with. discharged from the flowing medium, whereby the

lauv to uc. u ^ '. ™ - Removal of the generated gases is thus facilitated.

not objectionable. At the same time, the above-mentioned increase

The voltage to be applied to the electrodes is .0 J «' ^c ^" f ^{K of} _{the liquid} extraction medium, preferably direct voltage, but it is also possible P Continuous movement of the

borrowed. AC voltage to use de en half below at _constant speed and conwave equal to or longer than the time is m oer ν liquid extraction medium stelionic substances in the paper to be ions d.sso- g "^ '^^^ _E ttraction treatment safe, ziiert, and the ions obtained de ^ ^"then -5"^"e" e Stoch ^ "^ _{of the} extracts _{according to the invention} into the liquid extraction medium. Anι wena- _neut ^ _ionic substances hnr is an alternating voltage with a frequency of ^ ^{"a" n} f _v;. Nen ^P _{H, the} liquid _{in the} used less than 1 kHz, as in the later beschn ^ J ^ * ^^ _{are able to} shown such ionic Examples, the effect of the invention J "~ an alternating chip can _{from the} surface of the paper of the course by the application. | ^u ° _ktionsbehand i _ung easily by washing with voltage with technical frequency ™ * ™ ^ d £ S Wa2er removed The lower AC voltages can also be superimposed on _{a G «chspan w however} ^ _the ^ _{wQ dw treatment. If the magnitude} of the electrical failure of the paper is _about 5 mec. G, the washing suitable voltage to be applied to the electrodes can be omitted, provided that it is in the range of 1 to 800 volts / cm of the distance & ^ ^ ^^ ^ between the electrodes, preferably ™ J * ™ ¹ ™ £ _{s should have a} loss factor. If it is desired from 15 to 500 volts / cm of the distance, although the _f ve _{Ver ^^] ustfaktor also} the conductivity of the liquid extraction 30 rap> ^ is _{about QH% reduced}

mediums depends. _diums ⁵ ^ - ^? ~ "-« '-— ^ -' «-M ™ hr

Although the temperature of the flux, genMediums increased due to the current flow ™ £ ^ *% £ desirable that the temperature rises excessively Preferably it does not exceed 80 C, preferably it is not higher than 60 ° C. If required, the vessel is therefore cooled from the outside.

According to the invention, the medium itself is at rest or r ^ weghch es w, rdjedo ^ch

preferably, the liquid Extraktionsmed.um a nut «* ^ ^ ₀ ^ _{invention with reference to the Z} calibration constant speed determined oner m ^ explained. It shows

• direction to flow, ™ / ^a P ^ "™ Fig. 1 is a partially sectioned side view,

uniform loss factor at each position of the paper s _preferred embodiment of the device

,,. ⁶ ", - λ: - CvtraVtionsbehalt ^ p _urehruhrung the method of the present invention

youj? represents, ^^. ^^^ j of _the extraction vessel

length of the line XX in Fig. 1, fixed distribution of the conductivity of the nusMgc ..--— - _partially cut side view,

tion medium can be achieved. Such FheB ^ _{other Favor} g _th embodiment of the

The state of the liquid extraction _{measurement is represented by} ββε5 and

continuous feeding of the M ^ ¹⁰ ™ ⁸ , ^ ¹ ^ - - ^ = - - '«-« ^ hmttene side view, the

very low level of about υ, ΐ ^ νο icuuticn iai, the conductivity of the washing liquid must not be more than 6 μ S / cm, preferably not 2 μ S / cm exceed, while for the production of paper, the loss factor is about 0.20%, the conductivity the washing liquid to be used is not greater than 18 μ S / cm, preferably not greater than 10 µ S / cm. In general, washing water is used whose conductivity is not more than 20 μS / cm

uniform loss factor at jeoeraw. ».-- · -κ ™ «- if the extraction treatment under the "condition is carried out that J,» «» ^ medium at a constant speed Flows in a certain direction came from places fixed distribution of the conductivity of the flux gene Extrak tion medium can be achieved. Such a rnew

continuous z, uiunren u «TV M« «iims from with respect to the direction of movement of the P" F " ™

represents extraction vessel, and F i g. 4 is a partially sectioned side view showing represents another preferred embodiment of the extraction vessel.

In Fig. 1 and 2, 1 denotes an extraction vessel, made of a non-conductive material such as synthetic resin. The vessel 1 is with a pair of Elkd provided those facing each other

with respect to the movementM ^ m ^ e --- ·. _k . made is uas uciaui ^ ₁ "" · - ---- -

are the same direction, provided in the ^ g ^{e "nchm"} ^ 4 _n te _n electrodes opposed to each other right direction or dnet _angeor in another 'S ^ ~, namely a same, for example, Pia-direction but is or | ^ »° g" _tin ^g _herges tellten anode 2 and a bespidsweae from Richtuni preferred _herges about the stationary state of the _{n] Het} tellten cathode 3. the platinum-conductivity distribution easily h ^e ^ ^e "e ⁿ _Fxtraktions _ anode 2 is thin from a Platinum plate made τλ: _ ci: -o """i," ^^^ ioVi.it of the liquid extraction ^ ^^ electrode holder 4 attached to the from

a heat-resistant synthetic resin is made. The electrode holder 4 is by means of bolts 6 on a

Mounting plate 5 arranged to be vertically movable

of the type of liquid ram · ** »» »- _{u The} plate 5 is also by screws 8 ω plan-

Conductivity, the applied voltage and the _{length η} ^^ ^ _{Rante des Geiäßes t attaches to}

of the electrodes. It is in the range of 0, U5 209551/415

the electrode holder 4 is bent upwards on one side, and the anode 2 is provided with a lead 9 connected, which is attached to the upper part of the electrode holder 4 and further to a power source (not shown) is connected. The cathode 3 is made of mercury, which is in a space is introduced through the inner wall of the vessel 1 and one extending from the bottom of the vessel 1 Partition wall 10 is limited. 11 with a lead to the cathode is referred to, which is connected to the power source (not shown) is connected.

The vessel 1 is also provided with an inlet pipe 12 for feeding a liquid medium into the vessel 1 and an outlet pipe 13 for draining the liquid medium from the vessel! Mistake. The tubes 12 and 13 are provided with valves 14 and 15, respectively. Denoted at 16 is a roll of paper P to be treated. The paper P is unwound from the roller 16 at a constant speed by a pair of pinch rollers 17 and fed into the vessel to pass between the electrodes 2 and 3, being immersed in the liquid medium M and over guide rollers 18, 19 and 20 to be led. The paper then comes out of the passage 1 and runs over a guide roller 21. Of these guide rollers, the rollers 19 and 20 are each arranged on bearings 22 and 23 in the vessel 1 so that they can rotate freely.

The paper taken from the passage 1 is passed over guide rollers 24, 25 and 26 and into a Wash container 27 out of which it is taken by means of pinch rollers 29. In this operation the paper surfaces are exposed to washing water exiting from nozzles 28.

With 30 heating rollers are designated by which the treated paper is dried. For the drying process an infrared heater can also be used. If the dryer is also available as a Device for removing treated paper is used, the pinch rollers 29 can be omitted will. Numeral 31 denotes a take-up roller.

Although that shown in FIG. 1 with a pair of electrodes facing each other is provided, multiple pairs of opposing electrodes can be placed along the desired Be arranged direction of movement of the paper. Each pair of these electrodes can be used in any Direction be arranged, horizontal, vertical or inclined.

The electrode can have a flat or curved plate shape. The distance between the electrodes is arranged so that the liquid medium flows in the desired manner and the paper in the desired manner Way can be moved. As long as the trouble-free movement of the paper is ensured, that can Paper in contact with the surface of the electrode. In the case of a mercury cathode, however preferably a small gap is provided between the surface of the mercury and the paper to avoid the To leave the mercury surface undisturbed. If the other conditions are the same, one is to large gap is undesirable because the electrical stress exerted on the paper is reduced, whereby the preferred distance between the electrodes is accordingly up to 5 cm.

Although various materials can be used for the electrode, it is used as the anode material Platinum or carbon desirable because they are rarely dissolved into ions. The cathode material is Platinum, carbon or mercury preferred. Aluminum. Iron, gold, silver, nickel, lead or the like. can also be used for the cathode. Mercury is advantageously used as the cathode material used because any deposit on the cathode is automatically attached to the peripheral edges of the Mercury electrode are brought and the electrode surface therefore always remains fresh. Preferred Combinations of anode material and cathode material are platinum-platinum, platinum mercury, Platinum-- carbon, carbon carbon, carbon mercury, and carbon platinum. The upper electrode can be designed so that the escape of gases (oxygen and hydrogen) generated by electrolysis of the liquid extraction medium, is easily made possible. To the Example, a number of electrodes are arranged at a suitable distance from one another, around the To allow the gases to escape in between, or a number of screen-like electrodes are connected to each other connected, each provided with gas outlets.

After the extraction treatment, the paper runs through the vessel containing washing water and if necessary, the paper is further washed with washing water exiting from a nozzle, as shown in FIG. 1 shown. In another embodiment of a washing device, an elongated trough-like Washer vessel used. In this washing vessel is taken out of the extraction vessel Paper inserted on one side, washed with a stream of washing water as it moves through the Trough moves and leads out on the other side. The wash water is from the outlet side of the paper fed, flows to the inlet side of the paper and is discharged there. In addition, the Washing device can be installed in the extraction vessel, as shown in FIG. 3 shown.

In Fig. 3, the same reference numerals denote as in Fig. 1 similar or identical parts. To the structure described in the previous embodiment the vessel 1 is provided with guide plates 32 and 33 facing each other, the Electrodes 2 and 3 and the guide plates 32 and 33 are arranged one behind the other. The top plate 32 is vertically movable on a mounting plate by means of bolts 34 in the same way as the electrode holder 4 35 attached, the fastening plate 35 being attached to the flange 7 of the vessel 1 by screws 36 is attached. On the other hand, the lower guide plate 33 has feet 37, which in at the bottom of the Vessel 1 fastened brackets 38 are fitted. Between electrodes 2 and 3 and the guide plates 32 and 33 the open end of a tube 39 is attached to the liquid extraction medium between to supply electrodes 2 and 3. The tube 39 is behind through the bottom of the Geiäßes inside and is provided with a valve 40 for adjusting the supply of the liquid medium, wherein the tube 39 extends through a retaining nut 41 which is attached to the bottom of the tub. Through an inlet pipe 42 Wasctovssser is introduced into the vessel 1 at the outlet side of the paper. The tube 42 is with a Valve 43 is provided and extends through the side wall on the outlet side of the paper into the vessel 1, the opening of the tube 42 being arranged close to the paper. The inlet pipe is from a

Retaining nut 44 held, which is attached to the vessel 1.

The washing water W added through the inlet pipe 42 mainly flows between the guide plates 32 and 33 along the paper path. On the paper inlet side of the vessel 1 there is arranged an outlet pipe 13 for the liquid extraction medium mixed with washing water. The washing water (flows from the open end of the pipe 42 to the outlet pipe 13. In the apparatus in FIG. 3, the liquid extraction medium between the electrodes 2 and 3 is a mixture of the washing water supplied through the pipe 42 and the liquid medium supplied through the pipe 39 The paper is subjected to the extraction treatment while passing between the electrodes 2 and 3, and thereafter the treated paper is sufficiently washed with washing water while it is advanced between the guide plates 32 and 33. The attachment of the guide plates is useful in controlling the The guide plates can also serve as electrodes if they are made of a suitable electrode material and connected to a voltage. In this case, the wash water between the guide plates is of very low conductivity and therefore becomes ionic substances in the paper hardly any d Extracted by the effect of the present invention, however, ions lying on the surface of the paper or ions in the washing water near the paper surface are removed upon ion diffusion, and thus washing is carried out more effectively. In the one shown in FIG. 3, the paper, after it has been subjected to the extraction treatment in the vessel 1, is washed and carried out of the vessel, whereupon, if necessary, it is stored in the apparatus shown in FIG. 1 is further washed and dried and then wound up in the same manner as in FIG. 1.

F i g. 4 illustrates an extraction vessel 1. which is provided with pairs of electrodes and a number of inlet pipes for supplying a liquid medium and / or washing water. In this drawing, similar parts are denoted by the same reference numerals as in FIG. The mercury cathode 3 is attached to the bottom of the vessel 1 at a corresponding depth and is connected by the supply line 11 to a power source (not shown). Opposite the mercury cathode 3, three platinum anodes 2 are arranged, which in the same way as in FIG. 1 and 3. As in the case of FIG. 1, paper is guided through the vessel 1 from left to right by means of guide rollers 19 and 20. Inlet pipes 45 and 46 are arranged on the paper outlet side and two inlet pipes 47 and 48 in the middle part, these pipes being provided with openings directed towards the paper infeed side. With 49 an outlet pipe for liquid is designated, which extends into the vessel 1 through its bottom and has an opening at a suitable height. The tubes 45 and 47 are secured in place by clamps 50 and 51 attached to the mounting plates 5 which each receive the anodes. The tubes 46, 48 and 49 are received by retaining nuts 52, 53 and 54, respectively.

For a better understanding of the present invention the following examples are given.

example 1

Wood chips were intensively decomposed by the Kraft method, and the sulfate pulp obtained for cables was then completely washed with deionized water to remove ionic substances. the Paper pulp was then rolled out in deionized water to the desired extent and passed through a Fourdrinier paper machine using

ίο deionized water processed into cable insulation paper. The cable insulating paper (hereinafter referred to as "insulating paper A") thus produced had the following properties which were measured according to JIS (Japanese Industrial Standard) C-2111 (1967).

Thickness (mm) 0.100

Apparent density (g / cm ³ ) 0.67

Air resistance (Gurley-sec / 100 cm ³ ). 2,230

Tensile strength (kg / mm ² ) 6.41

Strain (%) .".' 2.52

The insulating paper A was subjected to the extraction treatment using the apparatus shown in FIG. The device used contained a vessel 28 cm long, 28 cm wide, 12 cm high; Mercury served as the cathode and was placed in a container 25 cm long, 25 cm wide, 1 cm high; and a platinum plate 20cm long. 10 cm wide was attached above the mercury cathode and served as the anode, the platinum anode being arranged at a distance of 2 cm from the mercury cathode. 10 cm wide insulating paper A was introduced into the vessel along guide rollers 18 and 19 and moved continuously between the platinum anode and the mercury cathode at a speed of 120 cm / min (treatment time: 10 seconds), with the surfaces of the electrodes facing each other, but no contact with the paper while deionized water having a conductivity of 1 µS / cm was continuously introduced into the vessel through the inlet pipe 12 at a rate shown in Table 1 along the surface of the paper. The water was discharged from the outlet pipe 13, whereby the water level in the vessel was kept constant. DC voltage given in Table 1 was applied to the electrodes. In a few minutes, the conductivity of the water just below the paper at the end of the platinum electrode on the paper inlet side and the conductivity of the outflowing liquid increased and became stable to reach the same specific value of not less than 10 μS / cm. The conductivity of the outflowed water was given in Table 1 below. The paper moved between the electrodes in such a stationary state of conductivity distribution was completely washed by passing through the container 27 filled with washing water and then with deionized water having a conductivity of 1 μS / cm at the speed

speed of 50 to 200 ml / 100 cm ^{2 of} the surface of the paper was sprayed. The paper was then dried after it was pressed by means of the pinch rollers 2! was dehydrated, and thus treated paper was obtained.

The dielectric loss factors be; 100 "C de Paniers obtained calculated in the state of paper impregnated with oil by the following Procedures are given in Table 1.

Measurement of the dielectric loss factor of with oil impregnated paper

The calculation of the dielectric loss factor of the obtained paper was carried out in accordance with JIS C-211! (1967), except that the paper sample at a temperature of 105 ⁰ C vortrocknete first 10 hours in the air, the pre-dried paper 2. 4 hours mm at a temperature of 120 ° C under a pressure of about 0.1 Hg completely dried after it was placed between flat electrodes, which are specified in JIS C-2111, 3., the paper was impregnated with alkylbenzenes having a branched alkyl chain, the loss factor was at 80 ⁰ C is not more than 0.005%, and their The average molecular weight was about 258 and then the impregnated paper was measured at a load of 10 Ic V / mm. In this specification, unless otherwise specified, all values of the loss factor of paper have been determined in the same manner as above.

In this description, the conductivity of liquid medium was measured using a measuring electrode which contains two platinum wires α of one millimeter in diameter and 20 cm in length which are arranged at a distance of 1 mm from one another, as shown in FIG. 5 (the electrode constant of the measuring electrode was measured in advance using a calibrated reference electrode). The measuring electrode was brought into the measuring position, connected via lead wires to a Wheatstone bridge (not shown), provided with an input power source of 5VoIt, and a frequency of 1 kHz, the bridge was balanced, and the AC conductivity between the two platinum wires was measured.

Tabel

- Electricity in the stationary
State 100 ° C tan Λ from Conductivity of Supplied to the chamber
deionized water Applied voltage (A) received
treated paper drained water
in the stationary state (l / min) (V) (%) (μ S / cm) Isolation paper A
untreated 3 0.177 to 0.180 - 0.1 100 5 0.146 180 0.1 200 0.5 0.140 190 0.2 100 1.2 0.161 40 0.2 200 2.2 0.149 62 0.2 300 0.4 0.142 80 0.3 100 1.0 0.157 45 0.3 200 1.9 0.140 55 0.3 300 0.3 0.140 70 0.5 100 0.6 0.165 22nd 0.5 200 1.3 0.150 35 0.5 300 5.0 0.145 46 0.5 500 0.6 0.143 65 1.0 300 3.0 0.163 16 1.0 500 2.5 0.143 67 1.5 500 0.149 40

For comparison purposes, the following comparisons 1 and 2 were made.

Comparison 1

In this comparison 1, the same device as in example 1 was used. Insulating paper A 9 cm wide was attached between the opposing electrodes without touching the electrodes. About sixty-one of distilled water with a conductivity of 0.55 µS / cm was placed in the vessel and a DC voltage of 300 Volts was applied to the electrodes for 2.5 hours.

While the DC voltage was being applied, the conductivity of the distilled water was measured (The measuring point was directly under the paper), and it was found that the conductivity of the Liquid temporarily to a maximum value of 1 to 2 minutes after the voltage is applied about 6.0 μS / cm increased, then dropped to 2.0 μS / cm in 5 minutes and then an approximately constant one Value showed. After 150 minutes had passed, the value was still 2.5 μS / cm. 2.5 hours after when the voltage was applied, the

Delte paper taken from the jar and adequately treated with deionized water of a conductivity washed by 0.5 μ S / cm and dried.

The loss factor at 100 ^° C. of the paper obtained, measured in the same way as in Example 1, was

0.177%, and there was hardly any appreciable improvement in the loss factor compared with 0.180% which was the value before extraction. By carrying out the same treatment with distilled water as a liquid medium and having a conductivity of 1.0 μS / cm, the obtained treated paper was found to have a loss factor of 0.179% at 100 ° C. and no improvement in the loss factor thereof was found. In this case, the conductivity reached a maximum amount of about 7.0 μS / cm 1 to 2 minutes after the voltage was applied, decreased to 2.2 μS / cm in 5 minutes, and thereafter showed approximately a constant value. After the lapse of \ 50 minutes the value was 3 μ S / cm.

Comparison 2

/ Ο

Treated paper was obtained in the same manner as in Comparison 1 except that 9 cm wide insulating paper A was fixed in the vessel between the electrodes and immersed in deionized water whose conductivity was 1.0 µS / cm. DC voltage was applied 10 minutes after the paper was immersed. The loss factor of the paper obtained at 100 ^° C. was found to be 0.174%. The conductivity of the deionized water was measured at a point just under the paper. 8 minutes after immersing the paper, it was 5 μS / cm and after 10 minutes it was 10 μS / cm. After the DC voltage was applied, the conductivity value rose to 7 μS / cm in one minute,

then dropped to 2 μS / cm in 2 minutes and reached 4 μS / cm in 30 minutes.

Example 2

Treated paper was obtained in the same manner as in Example 1 except that 9 cm wide insulating paper A was advanced at a higher speed of 240 cm per minute (treatment time 5 seconds) and various voltages shown in Table 2 were applied and deionized water was introduced into the vessel with a conductivity of 1 μS / cm at various speeds given in Table 2. The loss factor of the paper at 100 ^° C. is also given in table 2.

Tabel

What is added to the vessel
deionized water Applied voltage Electricity in the stationary 100 ° C tan A from
received Conductivity of
drained water State treated paper in the stationary state (l / min) ' (V) (A) (%) (μ S / cm) Isolation paper A untreated - - 0.177 to 0.180 - 0.5 100 0.3 0.164 28 0.5 200 0.6 0.163 30th 0.5 300 1.5 0.147 80 . 0.3 100 0.3 0.163 30th 0.3 200 1.0 0.145 40 0.3 300 3.5 0.140 100 0.2 100 0.3 0.163 30th 0.2 200 2.5 0.145 100 0.2 300 3.5 0.140 100 0.1 200 4.5 0.138 190

In each of the cases recorded above, noticeable improvements in loss factor were achieved. It should be noted that under the low flow rate and high conductivity conditions of the liquid extraction medium, excellent loss factor improvements were obtained.

Example 3 5 <>

Using the same device as in Example 1, 10 cm wide insulating paper A was introduced at a speed of 1200 cm / min (treatment time: 1 second), and distilled water with a conductivity of 1 μ S / cm was fed into the vessel at a speed of 0, 5 l / min in a direction opposite to the direction of paper movement when a direct voltage of 500 volts is applied. A few minutes after the voltage was applied, the conductivity of the expelled water reached the constant value of J 30 μS / cm. The paper running between the electrodes in such a solid state was washed with deionized water with a conductivity of 0.5 μm and dried.

The loss factor of the paper so treated was found to be 0.142% for KX) 'C.

55

60 A similar treatment, carried out with a supply of the above-mentioned distilled water at a rate of 1 l / min, resulted in a loss factor of 0.148% at 100 ⁰ C. In this case, the conductivity of water reached approximately 6 minutes after the application of the voltage a constant value of 75 μS / cm.

Example 4

Treated paper was prepared in the same manner as in Example 1 except that industrial water having a conductivity of 150 µS / cm was introduced into the vessel at a rate of 0.1 / min and a DC voltage of 100 volts was applied. The loss factor of the paper obtained was at 100 ⁰ C, 0.145%. The conductivity of the discharged water in the stationary state was 180 μS / cm.

The insulating paper thus obtained was helically wound on a conductor with an outer diameter of 51.0 mm (and 1500 mm ² cross-sectional area) to a thickness of 19.5 mm and, after drying, was impregnated with laurylbenzene in vacuo to form an oil-filled 273 kV Manufacture cables. Untreated insulating paper A was also wrapped around a conductor of the same dimension to the same thickness

and after drying in vacuo, impregnated with laurylbenzene to give a conventional oil-filled 175-k V Cable to get. Various properties of these cables are given in Table 3 for comparison. Of these properties, the loss factor was measured with a Schering bridge, the electrostatic Capacitance with an ordinary capacitance measuring bridge, the insulation resistance with a direct one Method of deflection using a galvanometer, and the equivalent dielectric constant was calculated from the electrostatic capacity. About the maximum impulse breakdown load of the cable, the voltage applied to the cable was stepwise in steps of increased 10 kV each time up to 1550 kV, and at each At the increased voltage level, a negative pulse voltage was applied to the conductor 3 times for the test. the The amounts in the table are represented by the maximum impulse dielectric strength on the conductor, calculated from the values of the breakdown voltage. Furthermore, the maximum long-term AC breakdown load To determine, the voltage applied to the cable was increased stepwise by 15 kV at each step up to 520 kV, and each elevated voltage levels were held for 3 hours to cause breakdown. The recorded amounts are represented by the maximum dielectric strength on the conductor, calculated on the values of the breakdown voltage.

Tabel

properties
Cable samples

Tan (100 ⁰ C, 275 kV) (%)

Electrostatic capacity (20 ° C, 1 kHz) fcF / km)

Equivalent dielectric constant

Insulation resistance (20 ⁰ C) (megohm-km)

Maximum impulsive breakdown load (kV / mm).

Maximum long-term AC breakdown load (kV / mm)

The results given in the table show that the lead wire with the according to the present Invention produced insulating paper has electrical properties that the conventional Cables are far superior. Both cables were disassembled and each assembled material was examined. No wrinkles were found in either the treated or untreated paper Cracks found.

Example 5

Five types of liquid media with a conductivity of 80 ^{μS / cm at 20 0} C, given in Table 4, power cables, insulated with
treated paper

0.14

0.32

3.15

11 χ 10 *
125

51

Power cable, insulated with
untreated insulating paper A

0.22
0.33
3.30

5 χ 10 *

112

47

were made by soldering various chemicals in deionized water or an equal volume mixture of deionized water and methyl alcohol. The extraction treatment was carried out in the same manner as in Example 1 except that the liquid media thus prepared were each brought into the vessel at a rate of 0.1 / min and a DC voltage of 300 volts was applied. The loss factor of the paper thus treated at 100 ^° C. was given in Table 4, which shows that a satisfactory improvement in the loss factor was achieved in each case.

45

Tabel

Liquid medium Into the vessel
introduced
liquid medium
(l / min) Current under
stationary
State
(A) I0O ° C tan Λ des
received
treated paper
(%) Conductivity of
outcast
Liquid in
steady state
(μ ίί / cm) CaCLi deionized water
Ca (OH) ₂ deionized water
H ₂ SO ₄ -deionized water
NaCl deionized water
Ca (OH) _r deionized water methyl
alcohol 0.1
0.1
0.1
0.1
0.1 5
3.5
5
5.5
4.5 0.138
0.140
0.148
0.154
0.138 150
145
110
140
147

Example 6

Treated paper was obtained in the same manner as in Example 1 except that the distance between the electrodes was set at 4.0cm and that deionized water with a conductivity of 3 μS / cm at one viewed in Table 5

Speed was introduced and that the voltage indicated in Table 5 was applied. The received

Loss factor of the paper at 100 ° C was measured and the results are shown in Table 5.

Tabel

Supplied to the vessel
deionized water
(l / min) Applied voltage
(V) Electricity in the stationary
State
(A) 100 ° C tan 6 of
received
treated paper
(%) Conductivity of
drained water
in the stationary state
(μ S / cm) Isolation paper A
untreated
0.5
0.5
1.0
1.0 300
500
300
500 0.2
0.75
0.15
0.54 0.177 to 0.180
0.165
0.155
0.168
0.162 15.5 '
46.0
12.8
17.3

Example 7

In this example, the apparatus used in Example 1 was used, except that the distance between the electrodes was set to 1.5 cm. Extraction treatment was carried out in the same manner as in Example 1 except that deionized water having a conductivity of 3 μS 'cm was supplied at a speed shown in Tables 6 and 7, and insulating paper A 10 cm wide was supplied at speeds of 120 cm per Minute (treatment time: 10 seconds) or 600cm per minute (treatment time: 2 seconds) was introduced. The results are given in Table 6 (treatment at 120 cm / min) and in Table 7 (at 600 cm / min). Comparing Table 6 with Table 7, it can be seen that the higher the feeding speed of the paper, the more significant the improvement in the loss factor. This fact is quite advantageous in continuous industrial production.

Tabel

What has been added to the chamber
deionized water

(l / min)

Isolation paper A
untreated

1.5
1.5
3.0

Applied voltage
(V)

300
500
500

100 ° C tan Λ from Conductivity of Electricity in the stationary received drained water State treated paper in the stationary state (A) (%) (μ S / cm) 0.177 to 0.180 2.0 0.169 14th 2.5 0.159 25th 1.5 0.163 17th

Tabel

Added to the vessel
deionized water

(l / min)

1.5
1.5
3.0

Applied voltage
(V)

300
500
500

Electricity in the stationary
State

(A)

3.2

3.2 2.3

Example 8

55

100 't tan Λ of Conductivity of received drained water treated paper in the stationary state (%) (μ S / cm) 0.163 15th 0.143 63 0.160 23

6o

Sulphate pulp obtained by decomposing wood chips was washed sufficiently with industrial water. The pulp obtained was then in Industrial water rolled out and on a Fourdrinier paper machine using industrial water processed into cable insulation paper. So that produced cable insulating paper (hereinafter referred to as "insulating paper ß") had the following Characteristics:

Thickness (mm) 0.105

Apparent density (g / cm ³ ) 0.77

Air resistance (Gurley-sec / 100cnr ⁵ ) 576

Tensile strength (kg / mm ² ) 11.2

Elongation (%) 2.47

The same device was used as in Example 1, in which the electrodes are spaced 1.0 cm apart. The extraction treatment was carried out in the same manner as in Example 1 except that the insulating paper B of 10 cm in width was fed at speeds of 30 cm / min (treatment time: 40 seconds) and 3 cm / min (treatment time: 400 seconds), respectively, during Deionized water with a conductivity of 1 μ S / cm

was introduced into the vessel at an amount of 2 l / min while applying the voltage shown in Table 8. After washing with deionized water having a conductivity of 10 μS / cm, the paper obtained was dried. The loss factor of the treated paper at 100 ° C was measured, and the results are shown in Table 8. Lashing Comparison Table 8 contains the loss factor prior untreated insulating B at 100 ^c 'C and those of the insulating paper, which has been / cm gewascher only with deionized water has a conductivity of 10 μ S.

Table 8

Exlraklionzeit

(Seconds)

Insulating paper B
untreated

Insulating paper B, washed
with deionized water

40

40
400
400
400

Applied voltage
(V)

500
300
500
300
100

Current under 100 "C tan Λ of Conductivity of steady state received treated expelled water paper in steady state (A) (%) (μ S / cm) - 0.255 to 0.260 - 0.230 to 0.240 5.0 0.197 80 3.5 0.210 15th 4.5 0.1% 65 3.4 0.200 20th 0.5 0.215 12th

Example 9

Insulating paper A and insulating paper B were each subjected to the extraction treatment using the same apparatus as in Example 1 except that the material of the anodes was changed. The treatment conditions were: paper feed speed 120 cm / min (treatment time: 10 seconds); Conductivity of distilled water as a liquid medium 2 μ S / cm; Water supply 1 l / min; and applied DC voltage 500VoIt. As shown in Table 9, platinum or carbon dust (graphite) was used as the anode. The treated paper was sufficiently washed with deionized water having a conductivity of 1 μS / cm and then dried. The properties of the treated papers are given in Table 9 together with the untreated insulating paper A and B for comparison. The extraction treatment of the present invention gave little change in apparent density, air resistance, tensile strength and forward voltage except for the loss factor. Before these properties, the breakdown voltage; measured according to the method described in P. Ga ζ zana Priaroggia and G. PaIa η dri, "Rcse arch on the electric breakdown of fully impregnate"., paper insulation for high-voltage cables ", AIEi

Trans. (Power Apparatus and Systems) Vol. 74. P. 134 ^ and 1345 (1956), except that Laurylber.zo! zui Impregnation was used instead of conventional mineral cable oil. The one at different Temperatures measured loss factor was given in table 9 specified. The other values were determined according to the method of JIS C-2111.

Table 9

Thickness (mm)

Apparent density (g / cm ³ )

Air resistance

(Gurley-sec / lOOcm ³ ) ..
Tensile strength (kg / mm ² ) ..

Strain (%)

Dielectric strength

(kV / mm)

Ash content (%)

23 ° C

60 ° C

tan ό (%) 80 ° C

100 ¹ C

Before treatment

Insulating paper

0.100
0.67

2230
6.41
2.52

81

0.26
0.155
0.135
0.150
0.180

Insulating paper ß

0.105

0.77

576
11.2
2.47

79
0.38
0.245 0.200 0.220 0.260 After treatment

Plane anode

Insulating paper
A.

0.101
0.67

2280
6.49
2.50

82
0.13
0.150
0.130
0.135
0.140

Insulating paper
B.

0.104
0.77

580
11.8

2.43

81

0.22
0.235
0.182
0.180
0.196

Carbon Tanoclc

Isolation paper A

0.100

0.67

2250 6.48 2.49

82 0.11 0.150 0.132 0.136 0.142

Insulating paper B

0.105

0.77

585 11.9 2.41

81

0.22 0.235 0.181 0.180 0.195

Example 10

Extraction treatment was carried out using the same equipment as in Example 1. However, the inlet pipe 12 and the outlet pipe 13 were closed for the liquid, and there

Vessel 1 was filled with about 6 liters of deionized water with a conductivity of 1 μS / cm. 10 cm wide insulating paper A was inserted into the vessel 1 at a speed of 4 cm / min (treatment time: 5 minutes) and passed between a pair of the opposing electrodes immersed in the deionized water. A DC voltage of 30OVoIt was applied to the electrodes. The conductivity of the deionized water in the center of the electrode under the paper reached 12 μS / cm after 2 minutes, 18 μS / cm after 5 minutes and 20 μS / cm after 10 minutes after the start of the extraction treatment. The paper taken out of the vessel was completely washed with deionized water having a conductivity of 2 μS / cm and then dried. The loss factor of the part of the paper, which was taken 10 minutes after the start of extraction from the vessel at 10O ⁰ C was found improved to 0.160%.

Example 11

The same equipment as in Example 1 was used. However, the extraction medium was introduced through the pipe 13 on the paper inlet side and taken out from the pipe 12 on the paper outlet side with the liquid extraction medium moved in the same direction as the paper. Insulating paper A was moved between the pair of opposing electrodes at a speed of 60 cm / min (treatment time: 20 seconds), while deionized water having a conductivity of 1 μS / cm in the manner described above in the amount of 1 l / min was fed. A DC voltage of 300 volts was applied to the electrodes. The paper thus treated was sufficiently washed with deionized water having a conductivity of 0.5 μS / cm and then dried. The loss factor of the paper was 0.140% at 100 ⁰ C. In the stationary state, the conductivity of the liquid extraction medium just below the insulating paper A in the central part of the electrode was 40 μS / cm.

Example i2

The same apparatus as in Example 10 was used except that a pair of carbon electrodes were used as an anode and a cathode, respectively, facing each other with a space of 1.3 cm therebetween. 10 cm wide insulating paper A was moved at a speed of 30 cm / min (treatment time: 40 seconds) between the stationary electrodes in a stationary liquid with a conductivity of 32 μS / cm while an alternating voltage of 200VoIt and 60Hz was applied. The treated paper was then sufficiently washed with deionized water, the conductivity / amounted to 1.7 μ S cm, and then dried The loss factor of the part of the paper that 5 minutes after the start of extraction was taken out of the vessel was at 100 ⁰ C 0.150% . A part of the treated paper besides the above paper part was cut out as a sample and impregnated with conventional mineral cable oil, the loss factor of which at 100 ^° C. was 0.05%. The loss factor of this paper was found to be 0.152%.

Example 13

In this example, the extraction treatment was carried out using the method shown in FIG. 4 shown vessel executed. In the 210 cm long, 40 cm wide and 10 cm high vessel 1 was mercury at a height 0.8 cm filled as a cathode. Three platinum anodes 50 cm long and 30 cm wide were spaced apart 3 cm from each other. The distance

ίο between the anode and the cathode was on 2 cm set. The respective inlet pipes 45, 46, 47 and 48 had a diameter of 0.5 cm, and the outlet pipe 49 had a height of 3.5 cm.

30 cm wide insulating paper A was moved between the electrodes at a speed of 45 m / min (treatment time: 2 seconds), and water having a conductivity of 8 µS / cm was added to the space between the electrodes through the inlet pipes 45 and 46 in an amount of 15 l / min in total in the direction opposite to the direction of movement of the paper and discharged from the outlet pipe 49 in order to keep the level of the liquid medium constant. A DC voltage of 300 volts was applied to the electrodes. In this example the inlet pipes 47 and 48 were kept closed. The steady state of the conductivity distribution was established in a few minutes. In the steady state, both the conductivity of the water just below the paper on the side of the anode on the paper inlet side and that of the exiting water were 175 μS / cm. The paper was then sufficiently washed with deionized water having a conductivity of 0.5 μS / cm and then dried. The loss factor of the treated paper at 100 ° C. was 0.136%, which showed that a considerable reduction in loss factor was achieved compared to the 0.180% of the untreated paper.

Example 14

The chemicals shown in Table 10 were each mixed in an amount of 6 to 50 mg / l in deionized water having a conductivity of 0.5 µ S / cm to prepare three kinds of extraction liquid media having a conductivity of 30 µ S / cm. This extraction liquid medium was then introduced into the same vessel 1 as in Example 13 through the inlet pipe 48 at two different speeds shown in Table 10 to move the liquid medium in the direction of the paper feed side. Deionized water having a conductivity of 0.5 µS / cm and an amount of 5 L / min in total was supplied through the inlet pipes 45 and 46 to cause the water to flow to the paper inlet side. The inlet pipe 47 was kept closed. A direct voltage of 200 volts was applied to the electrodes. Insulating paper A was passed between the electrodes at a speed of 14 m / sec. The paper treated in this way was sufficiently washed with deionized water having a conductivity of 0.5 μS / cm and then dried. The loss factors of these papers at 100 ° C. are summarized in Table 10. The conductivity of the liquid extraction medium just below the paper at the end of the anode on the paper inlet side is also given in Table 10.

209551/415

Tabel

Added chemicals

CaCl ₂

HCl

MgSO ₄

Steady state electricity

60 40

45

32

65

42

By the

Inlet pipe 4 "

flowing liquid

medium

(l / min)

100 C tan Λ of
r retained treated
paper Leillahigkcit
of the liquid
Extraction medium 1%) (μ S / cm) 0.138 170 0.145 110 0.140 120 OU 50 90 0.138 180 0.140 115

Example 15

12 NHCl was added to deionized water with a conductivity of 0.5 μS / cm in an amount of about 6 mg / 1 in order to prepare a liquid extraction medium, the conductivity of which was 30 μS / cm, which was then described as in Example 13 , was introduced into the vessel by the inlet stirrer 47 'at 8 l / min to move the liquid towards the paper inlet side. Further, under the same conditions as in Example 14, the deionized water having a conductivity of 0.5 μS / cm was supplied through the inlet pipes 45 and 46. The inlet tube 48 was kept closed. A direct voltage of 200 volts was applied to the electrodes. In the same manner as in Example 14, 30 cm wide insulating paper A was passed between the electrodes at a speed of 14 m / min. The paper taken out of the vessel was sufficiently washed with deionized water having a conductivity of 0.5 μS / cm and then dried. The loss factor of the treated paper at 100 ° C. was 0.140%, while in the steady state the conductivity of the liquid extraction medium just below the paper at the end of the anode on the paper feed side was 119 μS / cm.

Example 16

35

45

The extraction treatment was carried out under the same conditions as in Example 15 except that the extraction liquid medium having a conductivity of 40 μS / cm prepared by adding HCl to deionized water having a conductivity of 0.5 μS / cm the inlet tube 47 was inserted into the vessel and that the liquid extraction medium with a conductivity of 15 μS / cm, produced by the addition of Ca (OH) ₂ in an amount of a few mg per liter of deionized water with a conductivity of 0, 5 μ S / cm, was also introduced into the vessel through the inlet line 46 at 2 l / min and that the deionized water with a conductivity of 0.5 μ S / cm was also introduced into the vessel through the inlet roller 45 at 2 l / min was introduced. The tube 48 remained closed. The loss factor of the treated paper at 100 ⁿ C was 0.138%. The steady state conductivity of the ejected liquid was 160 μS / cm.

Example 17

The extraction treatment was carried out under the same conditions as in Example 4, except that industrial water having a conductivity of 200 μS / cm was used as the extraction liquid medium. The paper was then washed sufficiently with deionized water having a conductivity of 5 µS.-crn and then dried. The loss factor of the treated paper at 100 ^° C. was found to be 0.145%. The result was exactly identical to that of Example 4.

The conductivity of the industrial water was measured during the treatment. Although the liquid added had a conductivity of 200 μS / cm. In this example, the conductivity of the discharged liquid in the steady state had a reduced value of 180 μS / cm. As can be seen in this example, the decrease in conductivity sometimes takes place depending on the feed speed and the type of paper, the amount and type of liquid medium added and the type of electrode material.

Protection is only sought for the process within the scope of the patent claims

For this purpose 2 sheets of drawings

Claims (6)

Claims: 14. The method according to claim 1 to 13, characterized in that an anode (2) made of platinum or carbon and a cathode (3) made of platinum, carbon, mercury, aluminum, iron, gold, silver, nickel or as a pair of electrodes Lead is used. 15. The method according to claim 14, characterized in that an anode (2) made of platinum and a cathode (3) made of mercury is used. 1. Method of manufacturing electrical insulating paper with a reduced dielectric 5 Loss factor at which the paper is sandwiched between at least one pair of opposing electrodes, to which voltage is applied, is placed in a vessel containing a liquid medium, characterized in that io the paper (P) continuously through a liquid Medium (Af) with a conductivity of little at least 10 μS / cm is moved and then the paper treated in this way is dried. 2. The method according to claim 1, characterized in that the invention relates to a method for manufacturing that the liquid medium (M) water ment of electrical insulating paper with a vermit a conductivity of at least 10 μ S / cm reduced dielectric loss factor at which the is. Paper between at least one pair facing each other 3. The method according to claim 1, characterized in that protruding electrodes are applied to the voltage shows that the liquid medium (M) is an aqueous 20, is introduced into a vessel that is a liquid rige solution is that contains at least one then dissolved medium. contains water-soluble ionic substance and an insulating paper is largely used as an insulating material Has conductivity of at least 10 μS / cm. rial in electrical power cables, electrical conductors 4. The method according to claim 3, characterized in that it identifies capacitors, transformers, etc. that the ionic substance is an aqueous 25 det. With the rapid growth of the performance-soluble Is a salt of inorganic acid. in recent years there has been a tendency to greater power transmission capacity due to higher Operating voltages existed in these electrical devices. As transmission voltages increase, dielectric losses become more and more of a limiting factor in power transmission capacity. Accordingly, there is an increasing need to reduce the dielectric loss factor of the insulating material. Since the dielectric loss factor of the insulation material is proportional to the square of the applied voltage, frequency and dielectric constant and the dielectric dispersion factor (tangent ό) of the insulation material, the increase in the indicated that the ionic substance corresponds to a voltage applied to it Increase in niche acid, organic acid or alkali is. dielectric dissipation factor. Therefore it is necessary- 7. The method as claimed in claim 1, characterized in that the dielectric constant and / or the dielectric is identified, that the liquid medium (M) has an aqueous-fresh scattering factor of the insulation material The solution is that a water-soluble one does not reduce the dielectric loss factor so contains ionic organic matter and keep a 45 low as possible. Has conductivity of at least 10 μS / cm. Although various attempts have been made so far 8. The method according to claim 7, characterized in that the dielectric loss factor draws that the aqueous solution also reduce one of insulating paper, none has contains ionic substance. these attempts have proven to be satisfactory. To 9. The method according to claim 1 to 8, characterized 50 in a previously known method of manufacture, characterized in that the liquid medium is one of insulating paper z. B. wood chips by the conductivity of 20 to 300 μ S / cm. Kraft method intensely decomposed, and the obtained 10. The method according to claim 1, characterized in that sulfate pulp is sufficient with a large indicates that the paper (P) is continuously washed in order to amount of deionized water to remove ionic substances through the liquid medium (Af) with a gel. The crowd will speed of 0.1 to 800 m / min is moved. then in deionized water in the desired 11. The method according to claim 1, characterized in the extent rolled out and marked with a Fourdrinier paper, that the paper (P) then machine using deionized Wasmit a washing water is washed, the water processed into cable insulating paper. After this However, the ionic substance in the process can have a conductivity of less than 20 μS / cm fibers are not removed sufficiently, and that 12. The method according to claim 11, characterized paper is not satisfactorily low in the characterization, that the wash water is a key factor. It also affects a long time ability of no more than 6 μS / cm. washing the mechanical strength of the paper. 13. The method according to claim 1 to 12, characterized in 65 Although it is possible to reduce the denoted, that the constant flow rate factor of the paper to some extent Maintaining the fluid medium (M) in the area at the expense of density results in the vervon 0.05 to 500 m / min. reduction in density results in a considerable loss 5. The method according to claim 4, characterized in that the salt of the inorganic acid from at least one of the compounds NH ₄ Cl (NH ₄ J ₂ SO ₄ , NH ₄ NO ₃ , NaCl,
Na ₂ SO ₄ , NaNO ₃ , Na ₂ CO ₃ , NaHCO ₃ ,
KCl, K ₂ SO ₄ , K ₂ CO ₃ , KNO ₃ , CaCl ₂ ,
Ca (NO ₃ ) ₂ , MgCl ₂ , MgSO ₄ , Mg (NO ₃ J ₂ ,
BaCl ₂ and Ba (NO ₃ ) ₂ consists. 6. The method according to claim 3, characterized