DE2433832C3 - Electrical insulating material - Google Patents

Description

Summary of the description

It is an electrical insulating material. that

a) 1,2-polybutadiene as a major part.

b) 10 to 150 parts by weight of styrene or styrene derivative

per 100 parts by weight of 1,2-polybutadiene,

c) 15 to 150 parts by weight of 2,4,6-tribromophenyl acrylate per 100 parts by weight of the mixture of 1,2-polybutadiene and styrene and

d) 100 to 300 parts by weight of talc powder per 100 parts by weight Contains 2,4,6-tribromophenyl acrylate.

The invention relates to an electrical insulating material.

There are various types of electrical insulation organic polymer compounds such as thermoplastic and thermosetting resins are known. In particular are used as insulating materials for back casting. Encapsulate and immerse electrical Components various thermosetting resins, such as. B. refractory epoxy resin and resin unsaturated polyester known. However, these resins generally have dielectric properties, which change strongly with 1 temperature changes, a high dielectric loss factor at high Temperature, low arc resistance and low tracking resistance. For these reasons are a fireproof epoxy resin and an unsaturated polyester resin as electrical insulating materials of electrical components for high frequency and high voltage not suitable.

The invention is based on the object of providing an electrical insulating material for back casting, overmolding, To propose encapsulation and immersion of electrical components for high frequency and high voltage, which has a low dielectric constant and a low dielectric loss angle, In addition, the dielectric properties hardly change over a wide temperature range change, which has a large arc resistance and a large leakage current resistance, a large fire resistance and has good mechanical properties, such as high crack resistance and fast curing speed, owns.

The invention is explained in more detail below on the basis of the description.

1.2 and 3 of the drawing are diagrams obtained by plotting the dielectric constant of electrical insulation materials after hardening the temperature have been obtained.

The electrical insulating material according to the invention consists of a major proportion of 1,2-polybutadiene. 10 to 150 parts by weight of styrene or styrene derivative per 100 parts by weight 1,2-polybutadiene, 15 to 150 parts by weight of 2,4,6-tribromophenyl acrylate per 100 parts by weight the mixture of 1,2-polybutadiene and styrene or styrene derivative and 100 to 300 parts by weight of talc powder per 100 parts by weight of 2,4,6-tribromophenyl acrylate.

The proposed electrical insulating material is superior in electrical properties Characteristics such as a low dielectric constant, a low dielectric loss tangent, a high arc resistance and high tracking resistance, and at the same time high fire resistance and good mechanical properties, such as z. B. high crack resistance. Accordingly, electrical components with superior characteristics, especially with regard to the electrical properties and flammability, using the new one Insulating material are produced according to the invention.

Furthermore, by using the proposed electrical insulating material, electrical components can be produced without affecting the properties of the embedded materials, such as e.g. B. Coils. Semiconductors and the like, because the resin is at a relatively low temperature hardened.

The 1,2-polybutadiene used in the electrical insulation material is a liquid prepolymer with a number average molecular weight (MW) preferably from 2000 to 5000 and a viscosity preferably from 5000 to 20,000 ocP at 25 ° C. This 1,2-polybutadiene is preferably subject to in Presence of 0.5 to 5% dicumyl peroxide as a catalyst when heated to 130 to 150 ° C is preferred for more than 60 minutes of a crosslinking reaction.

The hardened 1,2-polybutadiene has the following properties:

Hardness (Rockwell) .. M 80 (ASTM D 785)

Tear resistance It tears (ASTM D 1674)

Flammability ... It burns (ASTM D 635)

Dielectric constant 2.4 (ASTM D 150)

Dielectric

Lost tangent .. 0.001 (ASYM D 150)

Arc resistance 80 seconds (ASTM D 495)

Volume resistance 10 ¹⁶ ii-cm (ASTM D 257)

The above values show that the cured 1,2-polybutadiene homopolymer has a low dielectric Has Loss Factor However, as indicated above, is the length of time required for curing too long and the temperature required for hardening is too high for industrial use. Besides that has the 1,2-polybutadiene homopolymer, such as indicated above, other disadvantages, such as poor tear strength when the electrical component is in this is embedded. Another disadvantage of the 1,2-polybutadiene homopolymer is the easy flammability. Therefore it is not suitable for 1,2-polybutadiene only to be used as insulating material for electrical components.

An advantageous embodiment relates to an electrical insulating material that is used for electrical insulation is suitable, a fast cure rate, a low dielectric loss factor, a high arc resistance, high tracking resistance, has a high fire resistance and a high crack resistance. This insulating material contains 1,2-polybutadiene with a numerically average molecular weight preferably from 2000 to 5000, Styrene or styrene derivative, 2,4,6-tribromophenyl acrylate, Talc powder and organic peroxide as a catalyst. This material is treated by heating a temperature preferably higher than 100 ° C. in the presence, preferably from 0.5 to 3 percent by weight Catalyst, such as B. dicumyl peroxide, tert-butyl perbenzoate and benzoyl peroxide, hardened. Hardening can only take place at a temperature below 100 C. difficult to do.

It is a feature of the invention that the viscosity of the resin mixture can be lowered by using styrene or a styrene derivative as a crosslinking agent for 1,2-polybutadiene. Preferred resins include chlorostyrene. Divinylbenzene, vinyltoluene and ethylvinylbenzene. as shown below. CH - CH ₂

55

where X H, Cl, CH = CH ₂ . Is CH ₃ or C ₂ H _5.

A preferred amount of styrene or the styrene equivalent is 10 to 150 parts by weight each 100 parts by weight of 1,2-polybutadiene. With less than 10 parts by weight of Slyro! or styrene derivative the viscosity is not improved enough. With an increase in the relative amount of styrene or the styrene derivative decreases the viscosity of the resin mixture. If the amount is more than 150 parts by weight of styrene or styrene derivative have that Correspondingly hardened resin does not have a sufficiently high crack resistance wedge.

Another feature of the invention is that the 2,4,6-tribromophenyl acrylate is added to the mixture of 1,2-polybutadiene and styrene or styrene derivative as indicated above. 2,4,6-Tribromophenyl acrylate is polymerized with 1,2-polybutadiene and styrene or a styrene derivative (». The use of 2,4,6-tribromophenyl acrylate reduces the temperature and the time for curing of the mixed mixture and also increases the fire resistance As the relative amount of 2,4,6-tribromophenyl acrylate increases, the flammability of the cured resin decreases and the crack resistance of the cured resin also increases, but at the same time the dielectric loss factor and the degree of change in the dielectric loss factor decrease with change The preferred proportion of 2,4,6-tribromophenyl acrylate corresponds to 15 to 150 parts by weight per 100 parts by weight of the mixture of 1,2-polybutadiene and styrene or styrene derivative the fire resistance is insufficient and the crack resistance is not sufficiently improved If this proportion is more than 150 parts, the dielectric loss factor of the cured resin becomes higher. However, the hardened resin containing 2,4,6-tribromophenyl acrylate has the disadvantage of insufficient arc resistance and tracking resistance. Another feature of the invention is. that a talc powder is added to the resin mixture of 1,2-polybutadiene, styrene or styrene derivative and 2,4,6-tribromophenyl acrylate. By using a talc powder, the above-mentioned disadvantage is improved or mitigated. The general chemical formula of talc is Mg ₃ Si ₄ O ₁₀ (HO) I. and talc is also variously referred to as talc, talc powder, steatite, soapstone, pot stone, tailor's chalk or Spanish chalk. As the relative amount of talc powder increases, the arc resistance and the tracking resistance of the cured resin increase. Preferred proportions of talc powder correspond to 100 to 300 parts by weight per 100 parts by weight of 2,4,6-tribromophenyl acrylate. When the talc powder is less than 100 parts by weight per 100 parts by weight of 2,4.6-1 ribromophynyl acrylate, the corresponding cured resin is liable to be subjected to arc breakdown and current leakage. If the amount concerned is more than 300 parts, the blended mixture has too high a viscosity to allow for immersion / pouring. Back molding and encapsulation of electrical components to be suitable.

The invention is suitable for electrical insulating materials which include a mineral powder, such as e.g. B. molten Contains quartz glass, silica, mica and aluminum oxide.

The following examples illustrate the advantages of the electrical insulating material of the invention. the The odor resistance values contained in the tables were determined in accordance with DIN 53 480.

example 1

Mixed mixtures of 1,2-polybutadiene, styrene. 2.4.6-tribromophenyl acrylate, talc powder, dicumyl peroxide and benzoyl peroxide were, as in the Table 1 indicated, produced.

table

Components

1,2-polybutadiene (MW: 5000)

Styrene

2,4,6-tribromophenyl acrylate

Talc powder

Benzoyl peroxide

Dicumyl perox id

In table 1 variie :! the slyrolanleil from 0 to 200 parts by weight per 100 parts by weight of 1,2-polybutadiene and the proportion of 2,4,6-tribromophenyl acrylate makes 50 parts by weight per 100 parts by weight of the mixture of 1,2-polybutadiene and styrene, and the The proportion of talc powder is 150 parts by weight per 100 parts by weight of 2,4,6-tribiomphenyl acrylate. to 100 parts by weight of the mixtures of 1,2-polybutadiene. Styrene and 2,4,6-tribromophenyl acrylate become 2 parts by weight of dicumylproxide and 1 part by weight Benzoyl peroxide given as a catalyst.

Each of the mixtures shown in Table 1 was poured into a mold in which a hexagonal steel rod was placed as indicated in ASTM (American Society for Testing Materials) D 1674-59T. The mixtures were heated in an air oven for one hour at 120 ⁰ C and converted into a cured hard resin, in which the hexagonal steel rod was imbedded. The crack resistance was tested using these samples. The dielek table 2

Vjewichtstcilc Il III IV V Vl Mixture number 100 100 100 100 100 I. 5 10 80 150 200 100
f \ 55 60 90 125 .150 U 78
1.6
3.2 80
1.8
3.6 135
3
6th 188
3.7
7.4 225
4.5
9 50 / 5
1.5
3

Ϊό U, r'f nSChaftCn ^{FROM EVERY RESIN} "" rden "ach bn, P f? ° i ^{CVOn AS} ™ ^D15 ° ßcP'M- The light- Ih ^{% L} ;" Ζ ⁰ " ^jcdcm hardened resin was The RS" ^{,, * hOdC tested by AS} "TMD 495-58, according to f JS u ^" ^jCdem constant resin the RiRf ", v ^{ih0dC was tested by} ASTM D495-58. Η hf ^CS ? R; ^{On jCdem} Schärleten HanT was

V ° ^{n DIN (Daitsche Industric} - ^Uft - ^{DlC En} ^ ncleability of each

^{WUrdC by DCR Melhodc of gCprÜft} · ^Dic viscosity of comparable

at ^ n ^m r "*""* ^{measured with cincm high} viscosity at 30 C. Each of the mixtures given in Table 1 was measured at 20 ° C. for in

telescopic, "/" ™ ^{Luftofal Cr warms and in} ™ Sehir-

V ^ ^{arZUdl Dicoben} a

this

properties

Viscosity (poise)

Crack resistance

Flammability

Arc resistance (s)
Tracking resistance

Dielectric constant
(10 kHz)

Dielectric loss

Results and measured values

Mixture number

1 II

more than

1000

no

Tear

no

Burn

183

KA3C

2.95

0.005

more than

1000

no

Tear

no

Burn

183

KA3C

3.01

0.005

no

Tear

no

Burn

183

KA3C

3.12

0.006

IV

31

no

Tear

no

Burn

183

KA3C

3.28

0.007

Vl

no Tear Tear no no Burn Burn 182 181 KA3C KA3C 331 3.42

Q-007

The values given in Table 2 clearly show that the resins with styrene in an amount of 10 to parts by weight per JOO parts by weight of U-polybutadiene, as in the mixtures with the numbers Hl to V is indicated, excellent properties in with regard to the viscosity of the mixtures and the crack resistance, flammability, arc resistance Creep Resistance, Dielectric Constant and 65 of the dielectric composite of the cured resin. The resin with little or no Proportion of styrene, as in numbers I and II of the mixtures 0.009

^height

et, care Example 2

^Volume

Table 3

Components Parts by weight VIII IX X Xl XII Mixture number 100 100 100 100 100 VII 50 50 50 50 50 1,2-polybutadiene (MW 4000) 100 15th 22.5 100 225 300 Styrene 50 23 33 150 340 450 2,4,6-tribromophenyl acrylate 0 1.9 2.5 4th 6th 8.5 Talc powder 0 3.8 5 8th 12th 17th Benzoyl peroxide 1.5 Dicumyl peroxide 3

In Table 3 the amount of 2,4,6-tribromophenyl acrylate varies from 0 to 200 parts by weight per 100 parts by weight of the mixture of 1,2-polybutadiene and Styrene, the talc powder quantity is 150 parts by weight per 100 parts by weight of 2,4,6-tribiomphenyl acrylate and the amount of styrene is 50 parts by weight per 100 parts by weight of 1,2-polybutadine. 2 parts by weight Dicumyl peroxide and 1 part by weight of benzoyl peroxide

per 100 parts by weight of the mixture of 1,2-polybutadiene, Styrene and 2,4,6-tribromophenyl acrylate are added as a catalyst.

Each of the mixtures was heated for one hour in a test tube immersed in an oil bath, namely at 100, 120 and 140 ° C. The outer one Appearance of the resins was observed. The results are given in Table 4.

table 4th Properties of the
Mixture number VIII Har7.es X Xl XIl Heating
mingling
tempe-
rature VIl half
fixed IX hard hard hard fluid soft hard hard hard hard 100 ° C soft hard hard hard hard hard 120 ° C hard hard 140'C

Each of the mixtures in Table 3 was used for constant and dielectric loss tangents Hard resins, which were subjected to 40 hours at 120 or 140 ° C. in an air oven, were made according to those in Example 1 warmed up. The crack resistance. Flammability, arc-specified methods tested. The strength of the result obtained, Tracking resistance. The dielectric constant is given in table 5.

Table 5

properties

Results and measured values
Mixture number
VII VIII

IX

XI

XlI

Heating temperature

Crack resistance Flammability

Arc resistance (s) Tracking resistance Dielectric constant {10 kHz) Dielectric component

140 140 120 120 120 120 no no no no no no Tear Tear Tear Tear Tear Tear Burn self- no no no no extinguishing Burn Burn Burn Burn 120 181 181 182 182 184 KA3b KA3C KA3C KA 3C KA 3 C KA 3 C 2.70 2.86 3.00 3.21 3.48 3.90

© $ 02

0.004

0.005

0.007

0, Θί5

Table 5 shows that mixtures with the Nenunem &. up to Xl very good properties in terms of crack resistance, flammability . Show arc resistance, creep resistance, dielectric constants and the electrical loss tangent . In other words, the resins are

709614/373

with 2,4,6-tribromophenyl acrylate in the range of 15 to ISO parts by weight per 100 parts by weight of the mixture of 1,2-polybutadiene and styrene of superior quality. The mixture that reveals little or no 2,4,6-tribromophenylai.rvlate. as with the mixtures with the numbers VI! and VIII is shown. require a relatively high temperature in order to be / hardened to a hard shark, and furthermore, the hardened hard resins inherit poor results in indability. The dielectric constant in the range of 25 to 175 ° C of hardened hard resins is in Table 6

Fig. I shown. The shark / with a large crowd 2.4,6-tribromophenyl acrylate. as shown for the mixture with the number XII. has a higher Dielectric constant than other mixtures and exhibits a large change in dielectric constant with change in temperature.

Example 3

Mixed mixtures of 1.2-polybutadiene, Styrene. 14.6-tribromophenylacrylate. Talc powder. Dicumvl peroxide and ben / oyl peroxide were as shown in Table 6. manufactured.

Components

1,2-polybutadiene (MW 3000)

Styrene

2,4,6-tribromophenyl acrylate

Talc powder

Benzoyl peroxide

Dicumyl peroxide

Parts by weight Mixture number XM! XIV

100

50

75

2.2

4.4

100 50

75 38 2.2 4.4

In Table 6, the styrene content makes 50 parts by weight per 100 parts by weight of 1,2-poly butadiene and the

ί r Γ ^{11 e} 7 ' ^{aCI7lalanleil 50 parts by} weight per 100 parts by weight of the mixture of 1,2-polybutadiene and styrene and the proportion of talc powder varies from 0 to 400 parts by weight per 100 parts by weight of 2,4,6-tribromophenyl acrylate. Benzoyl peroxide and di cumyl peroxide are added as a catalyst.

XV

100
50

75
75
2.2
4.4

XVi

100
50

75
150
2.2
4.4

XVl!

100 50

75 225 1 2

4.4

XVlII

100 50

75 300 2.2 4.4

35

Table 7

properties

Viscosity (poise)
Crack resistance

Flammability

Arc resistance (s)
Tracking resistance

Dielectric constant
kHz)

Dielectric loss tangent

Each of the mixtures was heated in an air oven at i-i) L for one hour. The crack resistance, flammability. Arc resistance. Leakage current resistance, Dielectric constant and the dielectric loss tangent of each unhardened hard one Resin were tested according to the flat methods in Example 1. Those in table 7 apply results were received ""

Results and measured values Mixture numbers XIIl XlV

no

Tear

no

Burn

KAI

2.68

0.002

no

Tear

no

Burn

100

KA2

2.81

0.003

XV

10

no

Tear

no

Burn

180

KA 3C

2.92

0.004 XVI

48

no

Tear

no

Burn

182

KA3C

3.08

0.006

XVIi

100

no

Tear

no

Burn

193

KA3C

3.30

0.007

XVIII

more than 1000

no

Tear

no

Burn

198

KA3C

3.64

0.009

It can be seen from Table 7 that the mixtures with the numbers XV to XVII show very good properties in terms of viscosity, crack resistance, flammability, arc resistance, tracking resistance, dielectric constant and dielectric loss tangent. In other words, the resins with TaJfcpolver in the range of up to 300 parts by weight per 100 parts by weight of Iaftriformnphenytacrylat are of superior quality. 65

The hardened Haiz, which drives containing no or only a gerince amount TaOcpuIver how the mixtures nrt numbers XIH and XiV show poor trgebmssen the Lichtbogenfestigkeii and aerKnechstromfestigkeit shows respect to the resin with a ffoOai amount lalkpulver as in the Geaiisdh sur fa of Number XVIlJ _{m is} seen to be a m feo & e viscosity, usable to industries tough.

Example 4

^Gemis * e of 1,2-polybutadiene ³ * - ^ S-Tribromophenylacryiat TaBc-PeTOXJd Blid ond «t-

12th

Table 8

Components

1,2-polybutadiene (MW 4000)
Styrene
Chlorostyrene
Vinyl toluene
Divinylbenzene
Ethyl vinyl benzene
2,4,6-tribromophenyl acrylate
Talc powder
Dicumyl peroxide
tert-butyl perbenzoate
Benzoyl peroxide

Weight lines XX XXI XXIl Gcmisch-Nuinnicr 100 100 100 XIX - ■ —- 100 80 50 30th 50

XXIlI

100

50

XXlV

100

80 ._. 60 75 30th 120 90 100 20th 75 5.2 75 3.8 4th 75 100 100 1.9 2 100 4th 4th 4th 2 2

2.6

Each of the mixtures in Table 8 was heated for one hour at 120 ⁰ C in an air oven. The crack resistance, flammability, light arc resistance, tracking resistance, dielectric constant and dielectric loss tangent of the cured resins were tested according to the methods given in Example 1. The results shown in Table 9 were obtained.

Table 9

properties

Results and measured values

Mixture number

XlX XX XXl

XXIl

XXlIl

XXIV

Viscosity (poise) 20th 32 40 45 30th 44 Crack resistance no no no no no no Tear Tear Tear Tear Tear Tear Flammability no no no no no no Burn Burn Burn Burn Burn Burn Arc resistance (s) 181 182 181 181 181 182 Tracking resistance KA3C KA3C KA3C KA3C KA3C KA3C Dielectric constant (10 kHz) 3.02 3.15 3.05 2.91 3.04 3.00 Dielectric loss tangent 0.005 0.007 0.006 0.005 0.005 0.005

From Table 9 it can be seen that all Mixtures specified there have very good properties in terms of viscosity and crack resistance. Flammability, Arc resistance. Tracking resistance. Dielectric constant and dielectric loss tangent show. The dielectric constant in the range of 25 to 175 C of unhardened hard

5 °

constant of each mixture hardly changes over a wide temperature range.

Example 5

Mixed mixtures of 1,2-polybutadiene, a styrene derivative, 2,4,6-tribromophenyl acrylate. Talc powder, Dicumyl Peroxide, Benzoyl Peroxide, and Mineral

Resin is shown in FIG. 2 shown . The F i iz. 2 can powder were. like in the Table 10 specified can be seen that the Dielectric constancy manufactured. Table 10 Components Weight Mixture number XXV XXVI XXVlI XXVIII XXIX XXX U-polybutadiene (MW 3000) 100 100 100 100 100 100 Styrene 40 40 - - 20th 20th Chlorostyrene - 60 60 20th 20th 2,4,6-tribromophenyl acrylate 60 60 40 40 70 70

V

13th

14th

continuation

Components

Talc powder powder from molten quaiz glass Aluminum oxide hydrate powder Silica powder Antimony trioxide Benzoyl peroxide Dicumyl peroxide

Each of the mixtures in Table 10 was heated for one hour at 120 ° C in an air oven. The crack resistance, flammability. Arc resistance, tracking resistance, dielectric constant and dielectric loss tangent of cured resins were tested according to the methods given in Example 1. The results shown in Table 11 were obtained.

(iewichlstcile XXVJ XXVH XXVIII XXlX xx.x Mixture number 70 100 - XXV 160 - - ._ - 80 70 140 - _ 80 _ .. _ 80 180 30th 20th 20th 40 40 _ 2 2 -> 2.1 2.1 30th 4th 4th 4th 4.2 4.2 2 4th

Table 11 Results and measured values XXVI XXVIl XXVlII XXlX XXX properties Mixture number 55 65 50 81 68 XXV no no no no no 72 Tear Tear Tear Tear Tear Viscosity (poise) no no no no no no Crack resistance Tear Burn Burn Burn Burn Burn no 25th 185 120 182 31 Flammability Burn KA2 KA3C KA3a KA3C KA 2 181 3.12 3.39 3.50 3.23 3.35 Arc resistance (s) KA3C Tracking resistance 3.15 0.005 0.009 0.013 0.007 0.008 Dielectric constant (10 kHz) 0.006 Dielectric loss tangent

From Table 11 it can be seen that the resins with talc powder, as with the mixtures with the Numbers XXV, XXVII and XXIX are shown to have good properties in terms of arc resistance and Have tracking resistance. Resins without talc powder lead, however, as with the mixtures with the numbers XXVI, XXVIII and XXX, gave poor results in terms of arc resistance and tracking resistance.

For this purpose 2 pale drawings

Claims (4)

Patent claims: 1. Electrical insulating material, characterized in that that it a) 1,2-polybutadiene as a major part, b) 10 to 150 parts by weight of styrene or styrene derivative per 100 parts by weight of 1,2-polybutadiene, c) 15 to 150 parts by weight of 2,4,6-tribromophenyl acrylate per 100 parts by weight of the mixture of 1,2-polybutadiene and styrene or styrene derivative and d) 100 to 300 parts by weight of talc powder per 100 parts by weight of 2,4,6-tribromophenyl acrylate contains. 2. Electrical insulating material according to claim 1, characterized in that it becomes a hard one Resin has been cured by heating at a temperature of 100 "C in the presence of a peroxide is. 3. Electrical insulating material according to claim 1, characterized in that the 1,2-polybutadiene has an average molecular weight of 2000 to 5000. 4. Electrical insulating material according to claim 1, characterized in that the styrene derivative Chlorostyrene, divinylbenzene, vinyltoluene or ethylvinylbenzene is.