DE2917559A1 - ELECTRICAL INSULATION MATERIAL BASED ON CELLULAR AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Description

2 9 1 7 R 5

DESCRIPTION

The present invention relates to electrical insulating materials and processes for their production, and in particular an electrical insulating material based on Pulp and a process for its manufacture.

The demand for such materials (insulating paper and pressboard for electrical engineering) is increasing regardless of the fact that Electrical insulation materials based on synthetic polymers, Ceramic and other more developed and used more and more extensively.

Electrical insulation materials based on cellulose correspond in a number of their important dielectric properties as well as in their time stability and in one wide range of working temperatures does not meet the growing quality requirements imposed by the electrotechnical and radio technology industry.

The most important properties of it are dielectric energy losses in isolators that operate in AC networks are, for example, as intermediate layers in paper capacitors or as a cable winding. These become quantitative Losses evaluated according to the size of the tangent of the loss angle, which is referred to in the text as tg6. The lower this Value is, the less energy - for heat loss - is consumed, the more durable are the products in which it is respective electrical insulation material is used.

Another important property of electrical insulation materials is their specific resistance, which is usually found in Ohm cm is measured.

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ORIGINAL INSPECTED

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The mentioned dielectric properties influence the third important value, the electrical strength - this influence is the stronger, the less tgö and the specific electrical resistance in the range of working temperatures is more stable and the more they change during the use of products. It was for example found that the slope tgö due to the aging of cellulose increases the temperature inside a condenser which in turn accelerates the aging of cellulose and the further slope tgö and der mentioned temperature up to the occurrence of an electrical breakdown and failure of a capacitor or cable will. The lowering of the specific electrical resistance in connection with the Increase in working temperatures for other external reasons to lead.

A number of electrical insulation materials are known on the Base of pulp and a number of processes for their Manufacture aimed at improving the stabilization tgö and the specific electrical resistance. The processes mentioned consist of preparing paper pulp, pouring, compressing and drying the paper web. The lowering of dielectric losses through the introduction of chemical reagents, for example zinc salts {SU-PS 540003) and magnesium salts, (SU-PS 300562), into the paper pulp.

The reduction in the size tgö of the electrical insulation material can only be observed at elevated temperatures (80 to 140 ° C); at low temperatures (30 to 80 ^° C.) this reduction is insignificant.

An electrical insulating material based on this is also known of modified pulp and a process for its manufacture.

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ORIGINAL INSPECTED

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As modified pulp, borilated pulp is used / the one obtained by processing the cellulose with a Melt of the mixture of boric acid and urea or borax at a temperature of 180 to 260 ° C. with subsequent washing out .the unreacted boric acid is obtained with water (SU-PS'en 303390, 536275). The one produced in the aforementioned process Electrical insulation material has low dielectric dipole losses. The dielectric ion losses remain but unchanged. The aforementioned method is also complicated on a large scale and therefore found no practical application.

The aim of the present invention is to eliminate the drawbacks mentioned.

The object of the invention was based on the selection of a new chemical reactant for the processing to develop an electrical insulation material on the basis of cellulose from paper pulp or from paper web, which ensured the improvement of the quantity tg <S and the specific electrical resistance.

The main aim of the present invention is to reduce the size tgo and the increase in the specific electrical resistance of electrical insulation materials on the basis of the pulp and in the stabilization of the mentioned parameters during operation.

This object has been achieved in that the electrical insulation material on the basis of the pulp contains from 0.02 to 1.1% by weight of boron, based on absolutely dry material.

The process for the production of electrical insulation material on the basis of the pulp includes the preparation of Paper pulp on the basis of the pulp, its pouring off

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with production of paper web, compression, processing with a chemical reagent, the drying and the manufacture of the final product, according to the invention is called chemical reagent boric acid or boron compounds, which form boric acid when reacted with water and which are separated or taken together in an amount which relates to a boron content in the end product of 0.02 to 1.1% by weight on the absolutely dry material.

To simplify the processing of the paper pulp or the paper web with the chemical reagent, the boric acid should can expediently be used as an aqueous or aqueous-alcoholic solution. The use of boric acid in the form an aqueous-alcoholic solution enables paper with practically constant density without its significant deformations produce, which excludes the subsequent compaction of the paper web.

It should preferably be used as a pre-connection that is involved in the implementation forms boric acid with water, boric anhydride, metaboric acid or triethyl borate can be used, which are expediently are to be used as an alcoholic solution for the purpose of better processing of the paper pulp or paper web.

The substances used as a chemical reagent, namely boric acid or boron compounds, which react with water Form boric acid and which can be taken separately or together, both in the step of preparing the pulp as well as before pressing or drying.

The method according to the invention is carried out as follows. In a process known to specialists, paper pulp is prepared, the main ingredients of which are wood or cotton cellulose is.

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It can already be used in the pulp preparation stage Boric acid or boron compounds, such as boric anhydride, metaboric acid, triethyl borate or their mixtures are introduced will. The boric acid dissolves in water contained in the paper pulp, and the boric anhydride, metaboric acid or triethyl borate react with water to produce a boric acid solution. The amount of Boric acid or one of the boron compounds or their ^ mixture calculated so that the boron content in the end product is equal to from 0.2 to 1.1% by weight, based on the absolutely dry material, is secured.

The boric acid and the boron compounds can both be crystalline Form as well as in the form of solutions.

The boric acid should expediently be in the form of an aqueous or aqueous-alcoholic solution and a boron compound as the alcoholic solution Solution come into play.

The paper pulp thus produced is cast in one of the conventional methods and then pressed together and dried, for which the equipment available in paper mills and well known to the specialists is used will. When it is necessary to produce electrical insulating material with increased density, the paper web is calendered.

The introduction of boric acid, boron compounds or their mixture is also possible in other process stages, the production of paper pulp and the casting of the paper web before pressing or drying.

The introduction of boric acid or boron compounds into the paper pulp or in the paper web not only reduces dielectric ion losses in an electrical insulating material, but considerably reduces dielectric dipole losses and stabilizes the size tg6 of the absolutely dry electrical

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ORIGINAL INSPECTED

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insulating material in a wide temperature range - at a temperature of 60 to 120 ° C and a content of boron in electrical insulating paper from 0.27 to 0.45% by weight is exemplary show the quantity tgö practically constant.

When increasing the boron content in absolutely dry electrical insulation material to 1.1% by weight, the variable tgö changes insignificantly at different temperatures.

The electrical insulation materials produced in the process described based on cellulose have the following technical characteristics:

- Thickness, ym 5 -

- Volume mass, g / cm ^ 0.6-1.35

- Content of boron in wt .-%, based on

absolutely dry material 0.02 - 1.1

- tgö of dry electrical insulating paper, which is based on wood cellulose and has a density of 0.7 g / cm:

Tempera- For paper that is under For paper that is under Vertur C twist from deionized twist from technological Water is made water is made that

an electrical conductivity of about 250 mkS / cm and about 0.5 iriVal / 1 Contains sodium salts

0.00040 0.00035 0.00040 0.00050

tgö of dry paper, which is based on electrical insulating pulp and has a density of 1.2 g / cm:

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30th 0.00040 60 0.00035 100 0.00030 120 0.00035

29 "75ü9 - 10 -

Temperature for paper, which water is prepared under comparable For paper that is under ⁰ C Vertur application of deionized application of technoligschem water produced, the

has an electrical conductivity of about 250 mkS / cm and about 0.5 mVal / 1 Contains sodium salts

60 0.0008 0.0008

100 0.0008 0.0010

120 0.0008 0.0013

For a better understanding of the present invention, the following Examples listed.

Example 1

The electrical insulation paper is produced under laboratory conditions on the basis of pure electrical insulation pulp, which is obtained from softwood species using desalinated water.

The paper pulp is crushed in a laboratory mixer 10 g Elektroisolierzellstof fes, poured over with 1000 ml of 0.1% aqueous boric acid for one hour at 1000 rpm and by grinding the resulting suspension up to 95 ° SR in a laboratory grinder for 12 hours manufactured.

The paper pulp prepared in this way is diluted with 1000 ml of demineralized water, after which it is poured in a laboratory system, Pressing and drying the respective paper web produces paper that has a density of 0.7 g / cm ^, a thickness of 50 Has micrometers and 0.02 wt .-% boron, based on absolutely dry material contains.

Simultaneously with it from the same substance and in the same process as well as with the same equipment only under

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Use of demineralized water will make control specimens the electrical insulating paper, which has the same thickness and density as the paper containing boric acid.

The meanings of the quantity tg <5 are determined on the test items of the two types of paper.

The meanings of the variable tg6 are determined as follows. Paper specimens are assembled into a package with a thickness of 280 to 320 μm. The package is flat between two Electrodes with a diameter of 46 mm held at a pressure of 0.3 kp / cm and in a vacuum at a residual pressure of

- Λ Q

5.10 Torr and a temperature of 125 C for 2 hours. Then, the Prüflingspakete in vacuum at the said value of the residual pressure are cooled to test temperature, 30 °, 60 °, is 100 ° and 120 ⁰ C, and thermostatted at one of said temperatures, the electrodes on the measuring path a Schering bridge connected will. The tests are carried out using industrial alternating current with a frequency of 50 Hz and a voltage of 5 V / mkm, with the significance of the variable tg <S being read off directly from the Schering Bridge after it has been adjusted.

The meanings of the variable tg5, which are listed in Table 1.

TABLE 1

Temperature ⁰ C tgfi - size of the test objects that

Contains boron in the control test specimens

30 0.00105 0 _r 00105

6O 0.00085-0.00O85

100 0.00085 O _r OOO85

120 OrOOTO O, 0012

63QQ.237Q53.-t

ÖRfGINÄL INSPECTED

Example 2

Electrical insulating paper is produced under laboratory conditions on the basis of pure electrical insulating cellulose, of softwood species using deionized water is won.

The paper pulp is crushed in a laboratory mixer for half an hour at 1000 rpm of 10 g of electrical insulating cellulose, which is poured over with 1000 ml of 1.2% aqueous solution of boric acid, and by grinding the Any suspension produced up to 96 ° SR in a laboratory grinder for 16 hours.

The paper pulp prepared in this way is diluted with 3000 ml of demineralized water, after which it is poured in a laboratory system, Pressing and drying the respective paper web produces paper that has a density of 0.7 g / cm and a thickness of 50 μm, and 0.11% by weight boron, based on absolute dry material.

At the same time from the same raw material and in the same Procedure and with the same equipment using only deionized water, control test specimens are ge is made of the electrical insulating paper which has the same thickness and density as the paper containing boric acid.

The meanings of the size tg5 determined according to the methodology and at the temperatures listed in Example 1.

The determined meanings of the variable tg5 are shown in Table 2 listed.

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TABLE 2

Temperature, ° C tg6-size of the test items that

Contains boron, control test items

0.00105 0.00085 0.00090 0.0012

-3Ό 0.0009 60 0.0007 100 O, 0007 120 O, 0007 Example 3

Electrical insulation paper is based on laboratory conditions made of pure electrical insulation pulp, which is obtained from softwood species using deionized water.

The paper pulp is produced in a laboratory mixer by comminuting 10 g of electrical insulating _{cellulose 7,} which is poured over one another with 100 ml of 28% aqueous solution of boric acid and 900 ml of deionized water, for half an hour at 1000 rpm.

The grinding, thinning and production of paper test specimens and the production of control test specimens from electrical insulating paper which does not contain boron are then carried out as in Example 2 described above. The thickness of the test specimens is 50 μm and the density is 0.7 g / cm ³ with a boron content of 0.25% by weight, based on absolutely dry material.

The test of specimens of the two types of paper is carried out as in Example 1.

The meanings of the quantity tgo, which are listed in Table 3, are found for the tested paper test specimens.

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- 14 TABLE 3

Temperature ⁰ C tgo size of the test items ^ that

Contains boron, control test items

0.00105 0.00085 0.00090 0.0012

0.0006 6O 0.0005 100 0.0005 120 0.0005 Example 4

Electrical insulation paper is based on laboratory conditions made of pure electrical insulating cellulose from Softwood species is obtained using deionized water.

For the production of laboratory paper test specimens, paper pulp is used which contains 2% cellulose and which is used on an industrial scale will be produced. 100 g of the paper pulp mentioned are ground up to 96.5 ° SR in a laboratory grinder. then 30 g of boric acid are added to the same, and the volume of the mixture by adding deionized water to 1000 ml brought. After mixing the diluted paper pulp for three minutes by casting, pressing and drying the respective paper web in a laboratory paper machine are electrical insulating paper test specimens with a thickness of 50 μm and a density of 0.7 g / cm, which contain 1.1% by weight of boron, based on absolutely dry material.

Same way, just using deionize ~ water, control specimens are made from electrical insulation paper that does not contain boron. Determining the size tgö is carried out as in Example 1.

The meanings of the tgS size, which are listed in Table 4.

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TABLE 4

temperature

tg5 size of the test items that

Contain boron,

Control test items

30th 0.00050 60 O, 00040 100 0.00035 120 0.00040 Example 5

0.00105 0.00085 0.00090 O, 0012 O

Capacitor paper that is produced on a large scale using deionized Water is produced in all process stages and that has a mass of 13 g per 1 m, a moisture content of 8% and a density of 0/8 g / cm _, is wetted with an 8% aqueous solution of boric acid until a moisture content of 26% is reached. That Moistened paper is subjected to calendering to a density of 1.2 g / cm and dried. From the same paper which is only moistened with deionized water, control specimens are produced in the same process.

The test specimens produced are subjected to the complex tests. The meaning of the tg6 size is as in Example 1 determined. The other technical values mentioned below are determined by known methods.

The meanings of the values of the test and control specimens made of electrical insulating papers are shown in Table 5.

If-

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TABEL

No. Description of
Characteristic value

Examinees who

Contain boron,

Control test items

Thickness, μία
Density, g / cm
Tear length, km

Specific electrical conductivity of a aqueous extract,

10.6 1, 20 9.6

Specific electrical resistance of dry paper, ohm · cm at one Temperature of 120 ° C

Dielectric constant 3.9 * 10
2.9

16

Tangent of the dielectric loss angle of the paper soaked with trichlorophenyl (in small capacitors) at a temperature of ⁰ C

20 0.0021

60 0.0018

10Q 0.0017

120 0.0020

Content of. For,% by weight based on absolutely dry Material O, 27

10.4 1.19 9.7

mkS / cm 11 10 pH aqueous extract
Breakdown voltage
for a layer of paper V 6.8
490 7.0
490 Tangent of the dielectri
loss angle
of dry paper
at one temperature
from ⁰ C 30th 0.0012 0.0020 6O 0.00095 0.00165 100 0.00095 0.0018 120 0010 0023

2.8 x 10 3.1

0.0035 0.0030 O, O032 0.040

ORIGINAL INSPECTED

Example 6

Ordinary capacitor paper that is used on a large scale using in all process stages of water with an electrical conductivity of 250 mkS / cm and a content of sodium salts of 0.5 mVal / 1, which has a density of 0.76 g / cm, is with 8% aqueous solution of boric acid until a moisture content is reached of 25%, moistened, subjected to calendering until a density of 1.2 g / cmr ^ is reached and dried.

The same paper, which is only moistened with technological water, will have the properties mentioned above processed in the same process for the purpose of producing control specimens.

The manufactured test items are subjected to complex tests , the results of which are shown in Table 6.

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TABEL

No. Designation of the characteristic value

Examinees who

Contain boron,

Control test items

Thickness, pm 8.2

Density, g / cm ³ 1.20

Tearing length, km 9.7

Specific electrical conductivity of an aqueous extract, mkS / cm at a module of 1: 50

pH aqueous extract 7.3

Breakdown voltage for a paper layer, V 400

Tangent of the dielectric loss angle of the dry paper at a temperature of ⁰ ° C

30 0.0010

60 0.0008

100 0.0010

120 O, OO135

Specific electrical resistance of dry paper, ohm-cm at one Temperature of 120 ° C 6.1

Dielectric constant

of dry paper 2.7

Tangent of the dielectric loss angle of a paper soaked in trichlorodiphenyl (in small capacitors) at a temperature of ⁰ C

2Ό

60
100 120

Boron content,% by weight, based on absolute

dry material O, 45

8.2

1.20

9.5

26th
7.6

400

0.0023 0.0019 0.0032 0.0068

2.8-10 3.1

0.0021 0.0035 0.0018 0.0032 0.0018 0.0046 0.0025 0.0081

::; 3/053 ORIGINAL INSPECTED

2317553

Example 7

Electrical insulation paper on the basis of pure electrical insulating pulp made from softwood species from deionized: water is prepared as follows.

Paper pulp which is produced on an industrial scale and which has a concentration of 0.23% by weight pulp, and up to 96 ° SR is ground, the headbox becomes a Taken from paper machine. 14 g of boric anhydride are added to the 1000 ml of the paper pulp mentioned, with mixing and mixed for 3 minutes.

When introduced into the paper pulp, the boric anhydride reacts together with the water contained therein with the formation of boric acid according to the following reaction scheme:

^B 2 ° 3 ^{+ 3 H} 2 ° ~ * ^{2 H} 3 ^B ° 3

From the paper pulp processed in this way in a laboratory paper machine by casting, pressing and drying the paper web test specimens are produced from electrical insulating paper with a thickness of 50 μm and a density of 0.7 g / cm, the 0.9% by weight boron, based on absolutely dry material.

By doing. same procedure, with the exception of the introduction of Boric anhydride, and with the same equipment become control specimens made of electrical insulation paper that does not contain boron with the same thickness and density,

On the specimens of the types of paper mentioned, according to the In the methodology described in Example 1, the meanings of the tg <5 size which are listed in Table 7.

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TABLE 7

Temperature ⁰ C tg5 size of the test items that

Boron contain control specimens

0.00105 0.00O85 O.00090 0.0012

30th 0.0005 60 O, 0004 too O, 0004 120 Ο, Ο0Ο4 Example 8

Similar to Example 7 with the use of metaboric acid as A boron compound becomes test specimens from the electrical insulation paper, the 0.9 wt .-% boron, based on absolutely dry Material, containing, and control specimens not containing boron prepared.

When interacting with water contained in the paper pulp, the metaboric acid forms boric acid according to the following Reaction scheme:

HBO ₂ + H ₂ O > ^H 3 ^BO 3

The meanings of the tgö-size, which are listed in Table 8.

TABLE 8

Temperature ⁰ C tg & -size of the test items that

Boron contain control specimens

30 0.00O5 0.001O5

60 O, 0004 O, 00O85

100 0.0004. 0.0009

12O 0.0004 0.0012

03 0 & 2 3 /

- '' ORIGINAL INSPECTED

7 Ο ■ ~ τ: c q - 21 -

Electrical insulation paper wixd under iäborbedingungen on the Based on pure electrical insulation pulp made from softwood using deionized water is won.

The paper pulp is crushed in a laboratory mixer for half an hour at 1000 rpm of 20 g of electrical insulating cellulose ^ which is filled with 1000 ml of deionized water, and by grinding the resulting suspension Manufactured up to 95 ° SR in a laboratory mill for 12 hours.

The paper pulp produced in this way is additionally diluted with 1000 ml of deionized water, after which it is carried out in a laboratory system produces a paper web by potting and pressing.

Half of the paper web produced is evenly processed over the entire surface with 10 ml of 0.1% aqueous solution of boric acid using an atomizer, repeatedly subjected to pressing and dried, producing electrical insulating paper which has a thickness of 50 micrometers and a density of 0.7 g / cmr and 0.04% by weight boron, based on absolutely dry material.

The second half of the paper web is dried and control test specimens are obtained from electrical insulation paper that does not contain boron and which have the same thickness and density.

Using the methodology described in Example 1, the meanings of the specimens mentioned for the two types of paper the tgö-variable, which are listed in Table 9.

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ORIGINAL INSPECTED

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TABLE 9

Temperature ⁰ C tg.fi-size of the test items, the

30th 0.0010 60 O, OOO8 100 0.0008 12O 0.0010 Example 10

Boron ^ contain control specimens

0.0011 Ό, 00085 0.0009 0 ^ 0012

Similar to example 9, test specimens made of electrical insulating paper, that is processed with boric acid, and control specimens made of the electrical insulation paper that does not contain boron, manufactured.

The test specimens have a thickness of 50 μm and a density of 0.7 g / cm.

The processing of the paper web for the production of the test pieces from the electrical insulating paper is carried out with 6% strength aqueous solution of boric acid. The test specimens produced in this way contain 0.9% by weight of I3or, based on absolutely dry Material-

On the test specimens of the two types of electrical insulation paper, according to the methodology described in Example 1, the meanings the tgö-size, which are listed in Table 10.

TABLE 10
Temperature ⁰ C tgö-size of the test items, the

Contain boron. ■ Control specimens

6O-0.0004'O.00085

100 0.00035 0.0009

120 Ό, 0004 0.0012

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, ORIGINAL INSPECTED

Example 11

Test specimens made of cable electrical insulation paper with a thickness of 120 micrometers and a density of 0.80 g / cm are made from pure electrical insulation pulp, which is obtained from softwood using deionized water, on an industrial scale using deionized water for the production of the paper pulp ³ manufactured.

The specimens mentioned are immersed in a 6% aqueous solution of boric acid for 5 seconds and dried. The density of the dry test specimens is 0.7 g / cm ³ and the boron content is 1.1% by weight, based on absolutely dry material.

On the test objects from the cable paper, which according to the invention processed with boric acid, and the specimens from the output cable paper, which does not contain boron, are processed according to The methodology described in Example 1 determined the meanings of the tgS variable, which are listed in Table 11.

TABLE TT

Temperature ⁰ C tg6-size of the test objects that

Boron contain control test line

60 0.0008 O, QOT8

100 O _t 0O09 O, 0025

12O Ο, ΟΟΤΤ Ο, 0049

Example 12

Made of pure electrical insulating cellulose, which is made of softwood underneath Application of en tionisxertem water is obtained on a large scale on the basis of deionized water, a suspension is prepared which contains 0.2% by weight of electrical insulation. having pulp. After grinding the aforementioned aqueous

ORIGINAL

Pulp suspension up to 96 ° SR will be two servings 150 g each taken.

One of the mentioned portions becomes 100 ml one after the other 0.08% aqueous suspension of the active alumina and 50 ml of 28% aqueous solution of boric acid and the other portion only Ϊ00 ml 0.08% aqueous suspension of the active γ-aluminum oxide added.

The volume of each of the portions after the addition of the ingredients mentioned is made up to 1000 ml with deionized water brought, mixed for 5 minutes at 1000 rpm, and from the paper pulps obtained in this way in one Laboratory system by potting, pressing and drying paper webs, test objects are made of electrical insulation paper, the 0.55 % By weight of boron, and specimens made of electrical insulating paper that does not contain boron. The fat of all test specimens is 50 μm and density 0.7 g / cm.

The meanings of the tgö variable are determined on the specimens mentioned in accordance with the methodology described in Example 1, which are listed in Table 12.

TABLE 12
Temperature ⁰ C tg6-size of the test objects that

60 13th O, 00045 100 O, 00040 120 0, 0OO45 example

Boron contain control specimens

O, OOO9 0.0010 0.00115

Electrical insulation paper is produced under laboratory conditions on the Based on pure electrical insulation pulp,

ff 3t: .13 / 05Jt. . "^ - '' ": ORIGINAL INSPECTED

the·; from '^ iaa ^ Xhol-z ^ - ^^ B ^. ^^ r-agile; sr <Dn enfeionized water

The paper pulp is crushed in a laboratory. jtiisofter during half an hour ibex 1000 rpm of 10g illegal sQl-iörzeiastGfE ^ which is overgassed with ΐΟΩΟml egg-salty hater., and -by grinding -on -accumulated suspension up to 6 "° SiR in a laboratory grinder for 16 hours . ^1, the thus prepared paper mass is diluted ±± m. 300Q ml desalted water, and then 73 g Triathylborat be the same verBiischt added and for 5.

When reacting the triethyl borate with water in the paper masae is contained, boric acid is formed according to the following reaction scheme :

₃ B + 3H ₂ O y 3C ₃ H ₅ OH + H ₃ BO ₃

The paper pulp then becomes test specimens from the electrical insulation paper with a density of 0.7 g / cm and a thickness of 50 μm and with a boron content of 0.37% by weight on absolutely dry material.

At the same time from the same raw material, in the same process and with the same equipment, but using only deionized water, become control specimens made of the electrical insulating paper having the same thickness and density as the paper containing boric acid.

The meanings of the tgö-variable according to the methodology and the temperatures are shown on the test items of the two types of paper determined, which are mentioned in Example 1. The determined characteristic values are listed in Table 13.

3 -j -11 -> 1 0 ΰ 3 1 ORIGINAL INSPECTED

ι a

* ife * - ^ öH3 ^ öi3e- derr ParäfXtnge / -die

Bar ejithaiten control specimens

3Q ", .-;" _ "," ■ - ■ JCf

6Q -_: ---_. O ^ QQQ4O; 0.00085

V30 .- "■"■■■■; . · ■ '- € "00035 0.00050

T20 ■ ;. "." .., eu.00040 0.00120

Example 14

Electrical insulating paper based on pure electrical insulating cellulose, obtained from softwood using deionized water is produced as follows.

Paper pulp which is prepared on an industrial scale and which contains 0.23% by weight of pulp, as well as ground up to 9 6 ° SR is taken from the headbox of the paper machine. A mixture of boric acid and boric anhydride is added to the 1000 ml of the paper pulp mentioned while mixing in an amount of 5 g and 1.4 g and mixed the same.

When introducing the above boric anhydride it reacts with the water it contains, producing boric acid according to the following reaction scheme:

^B 2 ° 3 ^{+ 3 H} 2 ° * " ^{2 H} 3 ^BO 3

From the paper pulp processed in this way in a laboratory paper machine by casting, pressing and drying of the paper web, test specimens are produced from Elektroisolxerpapier that have a thickness of 50 μm and a density of 0.7 g / cm and 0.27% by weight boron in the absolutely dry Paper included.

03ü J -. J / 053 1 -. ORIGINAL INSPECTiD

: - 27 - ^ -

In the same process, with ÄH & nalsine the introduction of the Equipment made from boric acid and boric anhydridef and with the same equipment are made control tests from the electrical insulation paper made that, the same thickness and density have, but do not contain boron,.

On the specimens of the types of paper mentioned in accordance with the example 1 described method, the sediments of tgjS size, which are listed in Table 14 .:

TABLE- 14 Test specimens Temperature, ⁰ C tgö-size of the Kcmtroll — test specimens Contain boron 0.001O5 30th 0.00070 0.000S5 60 0.0O06Q O, 00030 1OO O, 00055 σ, σοι 20 120 0.00055 Example 15

Similar to Example 14 using a mixture of boric acid and metaboric acid as the boron-containing reagent in an amount of 7.5 g and 3.5 g test specimens from the electrical insulation paper, the 0.45 wt .-% boron, based on absolute dry material, contains, and control specimens »the do not contain boron.

When reacting with water contained in the paper pulp, the above-mentioned metaboric acid forms boric acid "according to the following reaction scheme:. -./.-■ .... - ...".

HBO ₂ +

On the test specimens of the types of paper mentioned in accordance with the methodology described in Example 1, the significance of the tg6 size is determined, which is listed in Table 1S ^; are., ^ - ^;

$ 291,755

TABLE TS

Temperature, ° C tgö-size of the Examinees who Contain boron Control test items 30th 0.0OQSO OrOOlOS 60 Q, 00040 Q, OOO8S 100 0.00040 0.00090 120 O, 0004O 0.0012 Example 16

Similar to Example 14 using a mixture from boric acid and triethyl borate as a boron-containing reagent in an amount of 5 g and 12 g are test specimens made of electrical insulating paper, which contains 0.35% by weight of boron, based on absolutely dry material, and control test specimens are produced, which do not contain boron.

The above-mentioned triethyl borate forms boric acid when it reacts with water contained in the paper pulp following reaction scheme:

(C ₂ H ₅ O) ₃ B + H ₃ O y 3 C ₂ H ₅ OH + H ₅ BO ₃

The meanings of the tgS size, which are listed in Table 16.

TABLE 16
Temperature, ⁰ C tgS size of the test items that

Boron contain control specimens

3O O _r OOOS5 Θ, ΟΟΊΟ5

60 Q, 0004S O, 00O85

TOO 0 * 00045 0.0OQ9Q

T20 Q _r QQQ45 Ο, QO12α

ORIGINAL INSPECTED

Example 47

Electrical insulation paper is produced under laboratory conditions on the
Basis of the pure electrical insulation pulp, which is made of
Softwood obtained using desalinated water "is produced similarly to Example 1.

Then some of the paper test specimens are removed from an atomizer with a 4% aqueous-alcoholic solution of boric acid O weight ratio water: alcohol "is <6: 4)
processed in an amount of 0.3 ml Xosiing per 1 g of the absolutely dry paper. After the uniform processing, the test specimens are dried. The boron content is 0.36% by weight, based on absolutely dry paper. The density of the paper is 0.7 g / cm and a thickness of 50 μm.

On the paper test specimens processed in this way and not processed in accordance with those described in Example 1
Methodology, the meanings of the tgö variable are determined,
those listed in Table 17 below
will.

TABLE 17

Temperature, C tgö-size of the test objects, the

Boron contain control specimens

0.00105
0.00085
0.0009
0.0012

30th 0.0006 6O 0.0005 100 0.0005 120 0.0005 Example 18

Electrical insulating paper is produced under laboratory conditions similar to example ·.! ■ on the basis of .the pure electrical insulating cellulose, made from softwood.

030323/0531

■ ■ '", 2317559

- "3Θ -.

After this, Bin becomes part of the test items with a 3% grade
Alcoholic-aqueous solution of boric acid (weight ratio alcohol: "water is 14;" 1 ") processed in an amount of 1 ml of solution per 1 g of the absolutely dry paper.

The meanings of the tgS variable are determined on the test specimens of the paper processed according to the methodology described in Example 1 and not processed, as shown in Table 18
are listed. The density of the paper is 0.7
g / cm and thickness to 50 μκι.

TABLE 18
Temperature, ⁰ C tgS size of the test items that

Boron contain control specimens

30 Ό, Ο005 0.00105

6O 0.0004 0.00085

100 0.0004 0.0009

120 0.0004 0.0012

030023 / 0S31

Claims (8)

SHIP ν. FÜNER STREHL SCHÜBEi.-HOPi-- EBB1NGHAUS FINCK MARIAHILFPLÄTZ 2 & 3, MUNICH 9O POSTAL ADDRESS: POSTFACH 95 O1 6O, D-8OOO MDNCHEN 95 PROFESSIONAL REPRESENTATIVES ALSIAHILFPLÄTZOctr. £ ^ Γ ^^ ΙΖ Socialistitschesko j Revoljucii d.pl.chem. or. ursula, DIPL. INQ. DIETER EBBINGHAUS DR. ING. DIETER FINCK TELEFON (089) Λ Β 20 54 TELEX 5-23 565 AURO D TELEGRAMS AUROMARCPAT MUNICH DEA-19 287 April 30, 1979 Electrical insulation material based on cellulose and process for its production 1 ^.: Electrical insulating material based on cellulose, characterized in that it contains from 0.02 to 1.1 wt .-% boron, based on absolutely dry material. 2. A method for producing the electrical insulating material on the basis of the pulp according to claim 1, which the Production of paper pulp on the basis of cellulose, its casting with production of paper web, pressing, processing with a chemical reagent, includes drying and manufacturing the final product, characterized in, that as a chemical reagent boric acid or a boron compound 030023/053 * ORIGINAL INSPECTED bond is used, which on reaction with water forms boric acid, which are separated or taken together in one amount taken that the content of boron in the end product in the amount of 0.02 to 1.1 wt .-%, based on absolutely dry material, secures. 3. The method according to claim 2, characterized in that boric acid in the form of its aqueous or aqueous-alcoholic solution is used. 4. The method according to claim 2, characterized in that boric anhydride is used as a boron compound, Metaboric acid or trioxide borate is used. 5. The method according to claim 2 and 4, characterized in that the boron compound is used as an alcoholic Solution used. 6. The method according to claim 2 to 5, characterized in that active ingredients are used as a chemical reagent be taken at the pulp preparation stage. 7. The method according to claim 2 to 5, characterized in that active ingredients that are used as a chemical reagent taken before pressing. 03CC23 / 0 531 2 9 ί 7 υ 5 9 - 8. The method according to claim 2 to 5, characterized g e k e η η draws that one active ingredients. which are taken as a chemical reagent _{f introduces} before drying. ORIGINAL INSPECTED