DE1494253C - Vulcanizable molding compounds - Google Patents

Description

table

Water absorption Isolation constant dielectric dielectric
48 hours at 60 ^° C strain tensile strenght Basic Megohms ■ km vulcanized in steam kept in water Lead stearate 7 days at 70 ° (mg / cm ² ) 0.05 0.02. % kg / mm ² 180.64 0.13 0.20 650 0.430 O 90.32 4.5. 4.2 655. 0.420 1.5 83.87 370 237 660 0.415 3 58.87 1000 1150 665 0.400 6th 51.61 670 0.395 12th

These values clearly show the influence of the metal soap on the water absorption and the insulation constant, while the mechanical properties are practically unchanged.

The insulation constant [Ki) is defined by the following formula:

Table 2

20th

Ki =

Megohm * L log ₁₀ y * 1000 metal base

where Megohm = measured Megohm, L = length of the insulated cable in m, D = outer diameter of the insulation, d = diameter of the cable.

To the two values of the insulation constant given in the examples, i.e. to their value of vulcanization in steam, and after treatment in water, it should be noted, that cables that are in steam vulcanized at high temperature, saturated with moisture immediately after vulcanization are and-care to dry when left lying. A measurement of the isolation obtained under these conditions will therefore give different results depending on the humidity in the environment. This is the reason why, in the examples, the cable was kept in water for an additional 48 hours at 60 ° C and the measurements were taken after placing the cord in water for an additional hour had been kept at 15 ° C. This measure reveals the water content of the insulation kept constant so that the measurement results are definitely comparable. .

It is unimportant for the purposes of the invention that the metallic soap is added directly as such to the mixture will. According to a particular embodiment of the invention, the mixture can be prepared by the. Metal base and the organic acid are added separately. These two components react with one another in situ to form a corresponding soap. It should be emphasized here that magnesium or Calcium soaps are practically ineffective. Furthermore, an excess of the metal base (e.g. Pb- or Zn oxide) contributes to further improved results. This is illustrated in the following example.

Lead oxide

Zinc oxide .......

Magnesia.
Calcium hydroxide

Isolation constant, megohm km

dielectric

after

Vulcanization in steam

1800
2600

0.07

Dielectric kept for 48 hours at 6O ⁰ C in water

1500 1440

less than 0.01 3

While Pb and Zn significantly improve the results compared to Example 1, they are Mg and Ca oxides apparently ineffective. The situation remains unchanged even if in place of the separate addition of the latter oxides and stearic acid, an appropriate soap was added directly as described in the following example.

., B e i s ρ i e 1 3

In the mixture described in Example 1, the basic lead stearate was in one case by 6 parts Magnesium stearate and in another case replaced with 6 parts calcium stearate. The following results were received:

·. · ■ · ■ 'Table 3

Example 2

In the mixtures according to Example 1, the basic lead stearate was replaced by 5 parts of stearic acid and 10 parts of PbO, ZnO, MgO or Ca (OH) ₂ . The following results were obtained:

Magnesium stearate ..
Calcium stearate

Isolation constant, megohm km

dielectric

after

Vulcanization in steam

1.5
0.65

dielectric

48 hours

at 60 ° C in water

held

0.38 0.20

65 It can therefore be concluded that metallic soaps with a lead or zinc base lead to unexpectedly advantageous results, which by an excess the base can still be improved via the acid used, as by the values in the following Table is confirmed.

Table 4

Ethylene propylene copolymer

Sodium polybutadiene

Calcined kaolin

Chlorinated tert-butyl peroxide

sulfur

Stearic acid

Zinc oxide

Insulation constant after vulcanization in steam, megohms' km

Isolation constant after water treatment

Strain, %

Tensile strength, kg / mm ²

Water absorption after 7 days at 70 ^° C., mg / cm ² '

80

20th

100

4th

0.45

0.042

0.021 650 0.430

161.29 80

20th

100

0.45

1.2

130

76
600
0.480

65.81

80

20th

100

0.45

■ 2.4

2700

1060
700
■ 0.440

78.71

100

0.45

4.8

5800

2300
700
0.440

43.23

80

20th

100

. 4th

0.45

10

2600

1440
500
0.415

26.77

It should be added that the excess base does not necessarily go along with the soap base in the mixture must be identical, as has been confirmed by numerous other experiments. For example, the Prepare the mixture directly from the lead soap, while the excess base for example of zinc oxide, or it can for example of stearic acid and lead and zinc oxide can be assumed, the total oxides being in excess over the acid. After subsequent Treatment (kneading, calendering; extrusion, vulcanizing) are lead and zinc soaps formed within the mixture, the respective oxides partly in the unbound state stay and thereby improve the effect that is solely attributable to the soaps.

The amount of the above-mentioned excess of the metal base of the soap cannot here be definitive be determined, but it is to be assumed that the values in the table above will be familiar to those skilled in the art give adequate teaching in this regard. It can thus be seen that the increase in the zinc oxide content brings some decrease in tensile strength in conjunction with a decrease in elongation. It can also be seen that the insulation constant of mixture E with 10 parts of zinc oxide is somewhat higher than that of mixture C, which contains only 2.4 parts of zinc oxide, while it is well below the constant of the mixture D, which contains 4.8 parts of zinc oxide. So it can be clearly seen that a certain excess the metal base leads to an increase in the insulation constant, but this is the most favorable value this excess is determined in each individual case depending on the circumstances and desired results must become.

With regard to the influence of the various acids used in the context of the invention, refer to Table 5 referenced. The results are listed here with 12 different mixtures in which different Acids representative of the classes claimed in accordance with the invention were used should be.

Table 5

10

11th

Ethylene propylene

Copolymer

Sodium polybutadiene. '..

Calcined kaolin

Chlorinated tert-butyl per-

oxide

sulfur

Lead oxide

Caproic acid

Caprylic acid

Lauric acid

Palmitic acid

Stearic acid

Oleic acid

Benzoic acid

Salicylic acid

/ 3-oxynaphthalene carbon

acid

rosin

Naphthenic acid

100

0.75

1.5

80

20th

100

0.75 10

2.5

80

20th

100

0.75 10

3.5

80

20th

100

0.75 10

4.5

0.75
10

5.5

80

20th

100

0.75
10

80

20th

100

0.75
10

80

20th

100

0.75
10

100

0.75
10

80

20th

100

0.75
10

80

20th

100

0.75
10

continuation

1 2 3. • 4 5 6th 7th 8th 9 10 11th 12th Insulation constant according to
Vulcanization in steam,
Megohm * km 0.008 *)
0.018 *) 465
850 450
720 630
1000 750
1100 1800
1200 830
730 65
65 3400
2000 2600
2330 8400
11600 806
1500 Insulation constant according to
Water treatment ....

*) Increases after drying and then decreases again.

Mixture 1 was made without acid as a comparative sample. The isolation constants (0.008 and 0.018), those with this mixture (and, more generally, with mixtures, the copolymers of ethylene with α-olefins contain no zinc or lead soap), but care for the product as it dries to rise. However, this increase actually has no meaning as it is completely reversed if the product is kept in a humid environment for a certain period of time. Conversely, you can those obtained with mixtures 2 to 12 and, more generally, with mixtures according to the invention Insulation constants rise at most above the values determined after the water treatment, which the Maximum moisture absorbed, but in no case sink.

The addition of the acids provided according to the invention leads alone without the associated metal bases to barely remarkable results.

Example 4

In the mixture according to Example 1, the metal soap was replaced by 5 parts of stearic acid. After vulcanization of the mixture obtained in steam, an insulation constant of 21 megohm · km was determined. After treatment with water at 6O ⁰ C, the constant rose to 28 megohms · km.

When adding metal oxides alone, such as PbO and ZnO, even poorer results are obtained.

B e i s ρ i e 1 5

In the mixture according to Example 1, the metal soap was replaced by lead oxide in various amounts The following results were obtained:

Table 6

Ethylene propylene copolymer 80

Sodium polybutadiene.

(as plasticizer) 20

Calcined Kaolin 100

Dicumyl peroxide 2.5

Sulfur 0.12

After vulcanization in steam, the insulation constant had a value of 3. As a result of the stay in water at 60 ° C the constant rose to 6.

The same mixture, to which 10 parts of lead oxide and 5 parts of stearic acid were added, showed Vulcanization in steam has an insulation constant of 1500, which after being in water at 60 ° C rose to 1800.

It can therefore be concluded that the effect of the soaps used according to the invention by the nature of the Vulcanizing agent is not affected, at least not when using peroxides.

Example7

To investigate the influence of sulfur, two mixtures of the following composition were used manufactured: .

Isolation constant, Megohms ■ km Lead oxide Dielectric after crowd Dielectric after. Stay in water Vulcanization in steam at 6O ⁰ C 1.5 0.015 0.015 3 ■ 0.008 0.008 6th 0.019 0.019 12th 0.038 0.038

F. G 40- ethylene propylene copolymer ...
Sodium polybutadiene
(as plasticizer)
Calcined kaolin
Stearic acid
Zinc oxide
sulfur 80
20th
100
5
10
4th ■ 80
20th
100: Chlorinated tert-butyl peroxide ... 4th

Similar results were obtained with zinc and magnesium oxide.

The influence of the vulcanizing agent and sulfur on those achievable by using metallic soaps Results were also examined.

Example 6

The chlorinated p-tert-butyl peroxide was replaced by dicumyl peroxide. The mixture made had the following composition:

After vulcanization in steam, mixtures F and G had an insulation constant of 19 600 or only 0.032. After staying in water at 60 ° C values of 6860 and 0.014 were determined. This leads to the conclusion that sulfur has absolutely nothing to do with the effect attributed to the soaps.

Although the above examples relate specifically to the use of Zn and Pb oxides, it should be noted note that certain basic salts of the metals mentioned have a similar improving effect due to the fact that they are able to bond with the added organic acids at the expense of the basic part of their molecule.

Example 8

In the mixture according to Example 1, the metal soap was in one case by 5 parts of stearic acid and 10 parts of basic lead sulfate (PbSO ₄ -PbO) and

309 620/153

in another case replaced by 5 parts of stearic acid and 10 parts of basic lead carbonate (2 PbCO ₃ · Pb (OH) ₂ ). In the first case, the insulation constant was 650 after vulcanization and 950 after being in water at 60 ° C, while the corresponding values in the second case were 1500 and 1700, respectively.

When the experiments were repeated with basic salts in the absence of stearic acid, the isolation constant fell to values of the order of 0.01.

10

Example 9

IO Four mixtures of the following composition were prepared:, .α

Ethylene-propylene copolymer '.'..... 100
Paraffin oil (plasticizer) .... ,, .. ' p

Calcined kaolin 100

Chlorinated tert-butyl peroxide .... ^p 4

Sulfur 0.45

Basic lead stearate. (see table 7)

Table 7. Basic Water absorption in 7 days Isolation constant, megohm km Dielectric - 48 hours at 60 ^G C strain tensile strenght Lead stearate at 70 ⁰ C more relative dielectric vulcanized in steam kept in water humidity 0.06 0.04 % kg / mm ² O 27 0.14 0.19 660 ' 0.425 1.5 14th 4.7 4.3 667 0.417 3 13th 350 220 672 0.413 6th 10 980 1100 678. 0.397 12th 9 682 0.390

A comparison of the above example with Example 1 shows that the sodium polybutadiene used as a plasticizer without significant changes in the mechanical and insulating properties of the vulcanized Mixture can be replaced by another plasticizer.

The invention is also feasible with active soap mixes, e.g. B. with soaps of fatty acid mixtures (commercial stearin, so essentially a mixture of stearic and palmitic acid in different proportions), and soap mixes, containing various bases provided they contain zinc and / or lead. According to a further embodiment of the invention, each of the fillers in the mixture can act as a carrier serve its respective acid. For this purpose, the acid and filler can be pretreated in a suitable manner are to coat or soak the filler particles with the acid, whereupon the formed Mixture for kneading together with the remaining ingredients, d. H. the copolymer den Oxides or basic salts of the above metals, the vulcanizing agent, etc., into the mixer is given.

As a result of their good electrical insulating properties, the mixtures prepared according to the various embodiments of the invention can be used for numerous uses in all technical fields where these properties are required, to be needed. First and foremost is the field of insulating coatings on cables and conductors, insulating seals, To name insulation panels and floors. Another interesting application of the masses according to the invention are protective coatings, for example for pipes, against leakage currents and Corrosion.

Claims (1)

1 2 seeds from ethylene and α-olefins, b) organic patent claims : oxides and c) sulfur surprisingly good electrical Have insulating properties and due to the moisture-vulcanizable Molding materials from the environment practically not a) amorphous saturated copolymers of ⁵ ^ ™ * -? ^ ^will , ⁿ ' ^if they- in addition. 1 _ to ethylene and «-olefins, 30 percent by weight based on the polymers, one b) organic peroxides and metal soap with at least 6 carbon atoms in the { _e F c ι ^J acid residue from zinc, lead, cadmium or tin or the c) sulfur, ·. u j »* ■ ^ · t. , corresponding amounts of a mixture of one characterized in that they.zusatz- io corresponding organic acid and a base borrowed 1 to 30 percent by weight, based on that of the metal. Polymers, a metal soap with at least The metal base of the soap can be the above ge-6 Carbon atoms in the acid residue from zinc, lead, called metals in the form of oxides or basic Contain cadmium or tin or the corresponding salts. Suitable organic acids are Quantities of a mixture of an appropriate 15 saturated aliphatic acids. Also unsaturated organic acid and a base of the metal ent-. aliphatic acids can be used, beware. Assume that the reactivity of their double bonds is so low that vulcanization does not is disturbed. Palmithic, stearic, oleic acid can 20 are preferably used as aliphatic acids. Also suitable as acids for the purposes of The invention relates to vulcanizable invention aromatic or cycloaliphatic mono- Molding compounds, the amorphous saturated copolymers, carboxylic acids and resin acids. Of the former r of ethylene with α-olefins, especially ethylene. be naphthenic acid, benzoic acid and their homo- ^ Propylene and ethylene-butylene copolymers, containing halogen, o-oxybenzoic acid and ß-oxynaphthalene car- th. bonsäure including its homologues in the first place Process for the preparation of this line of copolymers recommended, while of the latter KoIo- and their elastomeric properties are known. phonium should be mentioned. Also, certain blends have been mentioned that are within the range of those mentioned above Containing copolymers, as well as the plasticizer 30 quantitative ratios are the. Improvements to the effect of low molecular weight properties of the masses that can be vulcanized with it, both with regard to the Polymers, e.g. B. butadiene polymers, on the electrical insulation capacity as well as in relation to named copolymers, described. Resistance to humidity of the environment In vulcanization mixtures, the copolymers (water repellency) the more pronounced the higher the soap of ethylene with α-olefins are included as 35 percent. This contradicts any logical expectation; Vulcanizing agents mostly organic peroxides, because of the high purity of the polymer used optionally in the presence of sulfur, 'quinone-' would require the addition of fairly small amounts of soap compounds and mineral and / or organic suggest to the harmful effect of such small see fillers, used. To counteract the amount of contamination. When mixing in suitable mineral 40 it has also been found that when using and / or organic fillers and / or the above-vulcanizable mixtures, the halogenated per-mentioned mitvulkanisbaren low polymers bil- oxyde and sulfur contain, the presence of the the mixtures without particular difficulty metal soap according to the invention, in particular the so that they can be used, for example, for zinc soap for electrical cables, tarnishing or fogging of electrical cables Kind and quite generally for use as 45 see lines completely prevented so that the ( electrical insulation molded or extruded expensive surface protection treatment of the cables, can be. . e.g. tin-plating of copper cables should be avoided In special circumstances, especially at May, when the lines with the improved Wed use be isolated from copolymers of very high loads. Molecular weight, e.g. B. 300,000 to 1,000,000 in the 50 The vulcanizable mixtures according to the invention Mixtures, however, are the electrical insulation properties and can contain other components, such as fillers Shafts made from these mixtures and plasticizers contain. Suitable as plasticizers Items not as it is for the use of the sodium polybutadiene or low polymer Mixtures in the field of electrical insulating paraffin oil. in general or in the field of electrical engineering.
would. Furthermore, depending on the manufacturing process used, large differences were found in the electrical components
tric insulating properties of the one and the same ,,. ... . , ■, " Mixture produced objects noted. Fer- 60 ^Four mixtures of the following composition were ner are objects made from ethylene copolymers. Mixtures containing seeds are produced, even ethylene-propylene copolymer 80 in the absence of fillers in environments of sodium polybutadiene (as soft high relative humidity highly hygroscopic, macher) 20 making their use in electrical engineering 65 Calcined kaolin 100 is further restricted. Chlorinated tert-butyl peroxide 4 It has now been found that vulcanizable mold sulfur 0.45 masses of a) amorphous saturated mixed polymer! - basic lead stearate (see table 1)