AU3362189A - Composition for electrically insulating material - Google Patents

Description

COMPOSITION FOR ELECTRICAL ISULATING MATERIAL Field of the Art The invention relates to the field of polymer compo sitions in particular to a composition for-electrical in 5 sulating material and can find application, for instance, for .n production of parts and units for electrical equip ment. Background Art Known in the art is a composition for electrical in 10 sulating material based on epoxy diane resin and polymethyl phenysiloxane (SU, A, 237973). This known composition for electrical insulating mate rial contains components in the following ratio, % by mass: compound 38-43 15 mica 33-43 glass 19-24 The compound is a mixture of epoxy diane resin with polymethylphenylsiloxane and a curing agent taken in the ratio 4:1:3. The composition contains cis-3,6-endomethy 20 lene-1,2,3,6-tetrahydrophthalic anhydride as a curing agent. This composition for electrical insulating material is used as insulation of windings in electrical machines operating in the temperature range from 50 to 1500C, that is its scope of application is limited. 25 Known in the art is a composition for electrical in sulating material containing epoxy diane resin, filler and curing agent in the following ratio of components, parts by mass: epoxy diane resin 100 30 filler 200-250 curing agent 55-70 (SU, A, 964738). The composition contains powdered quarts sand as a filler and a mixture of.polyanhydride, sebacic acid and 35 cis-3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride taken in the ratio from 1:3 to 1:1, as a curing agent.

-2 The applicability of this composition is also limit ed since at a temperature above 150*0 its physico-mechanical and dielectric properties drastically drop. Disclosure of the Invention 5 The present invention is based on the problem of providing a composition for electrical insulating material, by introducing a novel component, which would improve its physico-mechanical and insulating properties at high tempe ratures (up to 30000). 10 The object is attained by that the proposed compositi on for electrical insulating material, comprising epoxy diane resin with.20 epoxy groups and a filler, according to the invention, contains additionally oligocarbodiimide of the general formula: X-R N= C =N - R X, where 15 X=- N =C N-, -N = C =0; R = 0 QCH2&

CH

3 CH3 n = 0.01-10; and triethylamine with the following ratio of components, parts by mass: epoxy diane resin with 20 epoxy 20 groups 20.0-50.0 filler 36.0-69.0 oligocarbodiimide 5Q.0-80.0 triethylamine 0.01-1.0 The proposed composition makes it possible to produce 25 electrical insulating material with the following thermal, physico-mechanical and insulating prop/erties: -3 heat stability, 0C 420 initial mass loss- temperature by gravimetric analysis, 0.0 450 impact strength at 2000C, kJ/m 2 37 5 impact strength at 300 0 C, kJ/m 2 29 Brinell hardness, MPa, at 20000 130 at 30000 115 loss tangent of dielectric at 20C, .tgd' 2,1*10 10 at 200OC,tg 6 2,0*101 at 3000Ctg6" 3,0 1015 resistivity at 200C, fv Ohm cm 1,4-1015 at 200 0 c,v Ohm cm 2,31015 15 at 300*C0fy Ohm cm 2.2.1014 As a filler, it is expedient to use a mixture of chrysolite asbestos, glass fibers in the form of a braid 1-5 mm long and 5 mm wide and highly di-spersible amorphous silica in the weight ratio 30-50:5-15:1-4, respectively. 20 This allows to additionally improve physico-mechani cal properties of the material produced from the proposed composition at temperatures up to 300OC: impact strength at 20000, kJ/m 2 48 at 3000C, kJ/m 2 32 25 Brinell hardness at 30000, Ma 129 The indicated thermal, physico-mechanical and electri cal insulating properties of the produced material at high temperatures (up to 3000C) exceed those of the electrical insulating material produced by the known method (SU, A, 30 964748) and make it possible to use the material obtained from the proposed composition in products requiring high insulating and physico-mechanical characteristics and ope rating at temperatures up to 300*C. Best Mode to Carry aut the Invention 35 Oligocarbodiimide of the general formula: -4 X = -R =N = C N-Rn X, where X = - N = C= N-, - N =C -=0; R = CH'2

CH

3 CH 3 3 n = 0.01-10; contained in the proposed composition in the.amount of 5 50.0-80.0 parts by mass, acts as a copolymer, which consi derably improves the dielectric and thermal properties of the material produced from the proposed composition. Introduction of oligocarbodiimide of the indicated general formula in the amount exceeding 80.0 parts by mass, 10 is inexpedient since this provides no improvement of di electrical and thermal properties, but may cause the physico-mechanical properties of the material produced from the proposed composition to deteriorate due to the formation of dense network structure. 15 Introduction of oligocarbodiimide of the indicated general formula into the proposed composition in the amount below 50 parts by mass, causes the dielectric and thermal properties of the material produced from the proposed compo sition to deteriorate due the sparse network structure of 20 the cured composition. Triethylamine contained in the proposed composition for electrical insulating material acts a catalyst of the curing process when the indicated material is produced from the proposed composition. 25 Introduction of trietylamine into the proposed compo sition in the amount below 0.01 parts by mass, makes it impossible to achieve the required curing rate, thereby leading to insufficient structurization of the electrical insulating material produced from the proposed composition 30 and consequently to deterioration of the physico-mechanical properties of this material (impact strength, Brinell hard ness). Introduction of triethylamine into the proposed compo sition in the amount above 1.0 parts by mass accelerates -5 the curing rate above the required one, which may lead to defects in the structure of the electrical insulating ma terial produced from the proposed composition and deterio ration of its thermal and physico-mechanical characteris 5 tics. Introduction of chrysotile asbestos into the composi tion for electrical insulating material in the amount be low 30 parts by mass deteriorates the physico-mechanical properties of the material produced from the proposed com 10 position due to insufficient reinforcement of the composi tion. Introduction of chrysotile asbestos into the composi sition in the amount above 50 parts by mass fails to pro vide further improvement of the physico-mechanical proper 15 ties of the material produced from the proposed compositi on due to non-uniform distribution of chrysotile asbestos fibers in the mixture during mixing. Introduction of glass fibers in the form of a braid less than 1 mm long and 5 mm wide deteriorates the physico 20 -mechanical properties of the electrical insulating materi al produced from the proposed composition due to insuffi cient density of mass filling. Introduction of glass fibers in the form of a braid more than 5 mm long and 5 mm wide into the composition de 25 teriorates the physico-mechanical characteristics of the electrical insulating material due to non-uniform distribu tion of the fibers in the mass during mixing. Introduction of highly dispersible amorphous silica in the amount less than 1 part by mass into the proposed 30 composition deteriorates the rheological properties and, hence, deteriorates the molding of parts produced from this composition. Introduction of highly dispersible amorphous silica in the amount above 4 parts by mass leads to irregular 35 distribution of silica particles during mixing and fails to produce the required improvement of the rheological properties of the proposed composition, thereby deterio rating the molding of parts to be produced from this com position. The proposed composition for electrical insulating 5 material is obtained in the following way. First epoxy diane resin with 20 epoxy groups is blended in the given ratio with simultaneous mixing at 600C with oligocarbodiimide of the general formula: I - R fN = C = N - Rin I, where X - N = C = N -, -N=C =0; 10 R= 0 CH

CHE

3 QC3 n = 0.01-10; and triethylamine is introduced in the given ratio with simultaneous stirring. Thereafter the filler (a mixture of chrysotile asbestos, glass fibers 1-5 mm long and 5 mm 15 wide and highly dispersible amorphous silica) is added to the obtained mixture with simultaneous stirring to produce a homogeneous mass of the end product. To prepare the proposed composition it is possible to use chopped glass fibers in the form of a braid (1-5 mm 20 long and 5 mm wide) and highly dispersible amorphous sili ca with a specific surface of 175-380 m 2/g, the so called aerosil. To produce electrical insulating material from the proposed composition, it is cured in molds at a temperatu 25 re from 50 to 1800C for 10 hours at a pressure of 2 MPa. As a result electrical insulating material is produced in the form of electrotechnical and other items of various configurations and sizes. For a better understanding of the present invention 30 specific examples realizing various embodiments of the proposed composition are given herein below. Example 1 The proposed composition, consisting the following components, parts by mass: -7 epoxy diane resin with 20 epoxy groups 50.0 oligocarbodiimide of the general formula: X - R =C = N - R X, 5 where X =-N = C = 0 R = CH 2 50.0 n = 6; triethylamine 0.01 filler-powdered quartz sand 69.0 10 was prepared in the following way. First epoxy diane resin with 20 epoxy groups was mixed oligocarbodiimide of the indicated general formula in such a ratio that their con tent in the composition should be 50.0 and 50.0 parts by mass. Then 0.01 parts by mass triethylamine was added 15 during stirring followed by introducing a filler. Powdered quartz sand~in the amount of 69.0 parts by mass was used as a filler. The mixture was stirred to obtain a homogeneous mass. The obtained composition was cured in molds to pro 20 duce electrotechnical products at 50-180 0 C. As a result electrical insulating material was obtain ed in the form of a product with predetermined configura tion and dimensions. The results of tests of the thermal physico-mechanical and dielectric properties of the pro 25 posed composition are presented in Tables 1 and 2 given hereinbelow. Example 2 The proposed composition, consisting of the following components, parts by mass: 30 epoxy diane resin with 20 epoxy groups 20 oligocarbodiimide of the general formula; X - REN= C = N - R n where X =-N = C =N - R 35 n = 0.01 3 80 triethylamine 0 Q1 filler-powdered quartz sand 69.0 was proposed and cured as described in Example 1. The results of tests of the thermal, physico-mecha 5 nical and insulating properties of the material produced from the proposed composition are presented in Tables 1 and 2 given hereinbelow. Example 3 The proposed composition, consisting of the follow 10 ing components, parts by mass: epoxy diane resin with 20 epoxy groups 40.0 oligocarbodiimide of the general formula: X - R N = C =N - R X, 15 where X =-N = C = 0 R= 0 >-R( 60.0 n = 10 CH 3 triethylamine 0.5 filler-powdered quartz sand 69.0 was prepared and cured as described in Example 1. 20 The results of tests of the thermal, physico-mechani cal and insulating properties of the material produced from the proposed composition are presented in Tables 1 and 2 hereinbelow. Example 4 25 The proposed composition, consisting of the follow ing components, part by mass: epoxy diane resin with 20 epoxy groups 50.0 oligocarbodiimide of the general 30 formula: X = RfN = C = N -RX i, where X=- N = C = 0; R - CH 2 -& n = 6 50.0 triethylamine 1.0 chrysotile asbestos 50,0 35 glass fibers 1 mm long and 5 mm wide 15.0 highly dispersible amorphous silica with specific surface 175 m2/g 10 -9 was prepared and cured as described in Example 1. The results of tets of the thermal, physico-mechani cal and insulating properties of the material produced from the proposed composition are presented in the Tables 5 1 and 2 given hereinbelow. Example 5 The proposed composition, consisting of the follow ing components, parts by mass: epoxy diane resin with 10 20 epoxy groups 50.0 oligocarbodiimide of the general formula: X - R N =C 2 N - Rn X; where X = - N = C = 0; R =CH2 15 n = 6 50.0 chrysotile asbestos 5 mm long and 5 mm wide 5.0 highly dispersible amorphous silica highly specific surface 200 m 2 /g 1.0 20 was prepared and cured as described in Example 1. The results of tests of the thermal, physico-mechani cal and insulating properties of the material produced from the proposed composition are presented in the Tables 1 and 2 given hereinbelow. 25 Example 6 The proposed composition, consisting of the follow ing components, part by mass: epoxy diane resin with 20 epoxy groups 50,0 30 oligocarbodiimide of the genral formula: X - R EN = C = N - RI n X9 where I = - N = C = 0; R -& CH 2 50.0 n =6 35 chrysotile asbestos 40,0 glass fibers 3 mm long and 5 mm wide 10.0 highly dispersible amorphous silica with specific surface 380 m 2 /g 2.0 - 10 was prepared and cured as described in Example 1. The results of tests of the thermal, physico-mecha nical and insulating properties of the material produced from the proposed composition are presented in Tables 1 5 and 2 given hereinbelow.

- 11 Physico-mechanical characteristics of electrical insu lating material produced from the proposed composition Electrical Initial mass: Impact stren:Brinell hard insulating Heat :loss tempera:gth at 200 0 C ness at 20000, material stabi ture by ther: -tJ/m- a produced :ljty,-.Iflogravimet-.iLcat _; at at 1;at from compo-: 0C analysis, 00:2000C 300C-2000 .3000C sition Example 1 310 360 26 20 96 60 Example 2 360 450 22 15 100 80 Example 3 340 380 24 15 98 60 Example 4 420 400 40 29 131 115 Example 5 410 440 37 27 127 110 Example 6 410 440 39 27, 126 110 According to known inven tion (SU, A, 964738) 150 340 22 fragile 98 fragile - 12 Table 2 Insulating properties of the material produced from the proposed composition Electrical iisu- Loss tangent of dielectric, tgcP and lating material resistivity, fv produced from composition at 200C tgh :2f Ohmecm 1 2 3 Example 1 2.2.10-3 1.3-1015 Example 2 2.2.103 1.2-1015 Example 3 2.2.103 1.3*11015 Example 4 2.0.10-3 1.0.10 Example 5 2.0-10-3 1.3.1015 Example 6 2.0*10~3 1.2.101 According to known 2.5.10- 8.7.1014 invention( SU, A, 964738) - 13 Table 2 (cont.) Electrical in- Loss tangent of dielectric, tgd' and sulating mate- resistivity, JOv rial produced from composition at 20000 at 30090 t' :yv, Ohm. cm: tgd :Yv, Ohm. cm 1 4 5 6 7 Example 1 2,5-103 1.5,1025 3,6.10-3 2,510 14 Example 2 2.0.10 3 1.8.1015 3.4.10-3 2.3-10 14 Example 3 2.5.10-3 2.1-1015 3.5.10-3 2.5-10 14 Example 4 2.0.10~3 1.2.1015 3.0o-103 2.0.1014 Example 5 2.0.10-3 2.1.1015 3.0.10-3 2.1.1014 Example 6 2.0.10-3 2.3.1015 3.0-10-3 2.2.1014 According to known invention (SU,A, 8.0.10-2 1.3-1015 fragile fragile 964738) - 14 Industrial Applicability The proposed composition.for electrical insulating material can find application, for instance, in the pro duction of parts and units of electrical equipment, ope 5 rating at high temperatures (up to 3000C).

Claims (4)

1. A composition for electrical insulating material, containing epoxy diane resin with 20 epoxy groups, filler, characterized in that it additionally comprises oligocar 5 bodiimide of the general formula: I - R{N = C 2 N - R] I, where X= - N C 2 N -N = C = 0; R CH 3 3 n 0.01-10; 10 and triethylamine with the following ratio of the compo nents, parts by mass: epoxy diane resin with 20 epoxy groups

20.0-50.0 filler

36.0-69,0 15 oligocarbodiimide

50.0-8Q.0 triethylamine 0.01-1.0. 2. A composition, according to Claim 1, characterized in that as a filler it contains a mixture of chrysotile asbestos, glass fibers 1-5 mm long and 5 mm wide and high 20 ly dispersible-amorphous silica at their mass ratio of 30-50:5-15:1-4, respectively.