DE2164560C3 - Process for deforming and vulcanizing a vulcanizable material - Google Patents

Description

The invention relates to a method for deforming and vulcanizing rubbers or synthetic polymers mixed with an organic peroxide (this mixture is referred to below referred to as "vulcanizable material"). The invention specifically provides an excellent one Method for producing elongated molded bodies from a vulcanizable material accessible, in which the material flows through a nozzle with a long flow path, which causes the deformation and vulcanization to be led.

It is a common method to make elongated articles of vulcanized material by the vulcanizable material through a nozzle with a short flow path (which is only used to deform the Material is used) is pressed and the extrudate obtained by a high-pressure steam filled, elongated vulcanization chamber is performed.

A method for producing vulcanized elongated molded bodies has already been proposed, like vulcanized rods, pipes or

insulating cable with a vulcanized layer in which a vulcanizable material, such as a vulcanizing agent containing polyethylene, is extruded and vulcanized by passing it through a to the Vulcanization temperature of the material heated nozzle is pressed with a long flow path. This method will hereinafter referred to as vulcanization in a nozzle with a long flow path

The vulcanization in a nozzle with a long flow path has the following advantages over the conventional one Method of steam vulcanization:

1) The vulcanizate has exact dimensions and shows uniform dimensions in the longitudinal direction because the material in the nozzle with a long flow path during the entire deformation and vulcanization stage is firmly enclosed

2) The outer surface of the vulcanizate thus obtained is shiny and smooth, because during vulcanization the surface of the product is not covered with water droplets comes into contact, which often adversely affect the surfaces of the product.

3) When the vulcanization temperature is increased in steam vulcanization, the vulcanization pressure also increases. It is therefore difficult to perform the steam vulcanization at a temperature of more than 200 ⁰ C, because a vulcanization chamber must be constructed so that it can withstand considerably high pressures at these high temperatures. In contrast, in vulcanization using a nozzle with a long flow path, vulcanization at a high temperature, for example 250 ° C., can be easily carried out because the vulcanization temperature is set independently of the vulcanization pressure. The vulcanization time can therefore be shortened considerably.

4) The deforming and shrinking device can be made remarkably small and simple will.

Despite the described advantages to be maintained, the vulcanization was carried out with the help of a nozzle long flow path not used industrially. One of the difficulties which the industrial application of the The difficulty in preventing vulcanization in a nozzle with a long flow path is the molded To feed product smoothly through a nozzle with a long flow path.

To overcome these problems, numerous proposals have been made to improve the smooth passage of the to enable molded product through a closed narrow channel. It was using a Proposed channel whose inner wall is provided with a polished surface. An other suggestion consisted in the use of a passage or channel, the inner wall of which with a thin Layer of a perfluorocarbon resin is coated. Another possibility was mixing a molding aid, such as chlorinated hydrocarbon lubricants, Silicone oil or other lubricating fluids to the vulcanizable mass (US patent 29 72 780). Another suggestion is to apply a liquid lubricant, such as oil, to the inside surface of the Apply through the passage (US Pat. No. 3,054,142). The liquid lubricant acts as a release agent and avoids scorching and sticking of the molded product on the nozzle surface and serves also as a lubricant that facilitates the passage of the molded product.

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65 However, it has been found that even when a long flow path nozzle having a polished surface is used, only vulcanized products having rough or cracked surfaces can be obtained. It has also been found that the problem cannot be solved by using a long-travel nozzle coated with perfluorocarbon resin because the coating layer is easily damaged after a short period of processing. It has also been found that when using lubricants or molding aids, which are commonly used for shaping plastics and rubber, such as silicone oil and other oils, for vulcanization in a nozzle with a long flow path, the surface of the Vulcanizate became rough or cracked even though the molding aid was continuously fed onto the surface of the product. It has been found that, surprisingly, this phenomenon is caused by the loss of the lubricating and separating properties of the molding aid caused by gelatinization due to the action of the organic peroxide exuding from the vulcanizable material. The resulting gel sticks to the surface of the molded product or penetrates the molded product, creating a rough or cracked surface.

The invention is based on the discovery that, through the use of a very specific class of Molding auxiliaries with specific, critical physical properties are available for the first time is given, the deformation and vulcanization in a nozzle with a long flow path in a continuous to carry out industrial processes.

The invention relates to a method for deforming and vulcanizing a vulcanizable Material in which a mixture of a polymer vulcanizable with the aid of organic peroxide and of an organic peroxide is passed through a long flow path nozzle having a molding zone and a having subsequent vulcanization zone, while at the same time a molding aid on the inner surface of the Long flow path nozzle is fed in such a way that an uninterrupted film between the Inner surface of the nozzle and the polymer product! is maintained, which is characterized by that the molding aid used

a) a viscosity of at least 1.1 centistokes and not more than 3000 centistokes at 235 ° C,

b) has an absorption ratio in the polymer of less than 100 mg / cm ² at 150 ^° C. for 45 hours.

c) is not gelatinized in contact with the organic peroxide during vulcanization and

d) does not boil during vulcanization.

In the practical implementation of the method according to the invention, the molding aid has the effect of the inner surface of the long flow path nozzle and the molded product, its chemical and physical properties during vulcanization with the help of the mixed in organic Peroxyds constantly change, separate from each other. The molding tool that is on the inside surface of the nozzle is provided with a sloping flow path and in this way separates the nozzle from the deformed product, should be distributed over the entire interface and form an uninterrupted film. That on the

Molding agents transferred to the surface of the molded product should not be missing anywhere as the molded product moves through the nozzle.

The molding aids used for the purposes of the invention must have a viscosity of at least 1.1 centistokes at 235 ⁰ C, preferably about 5 Cenüstokes have.

If the viscosity of the molding agent is less than 1.1 centistokes, the molding agent tends to flow locally, and it is difficult to cause the molding agent to spread evenly over the entire interface between the inner surface of the long-travel nozzle and the surface of the molded product, so that an uninterrupted film is not easily formed. A viscosity of 3000 centistokes is a practical upper limit. If the viscosity of the molding aid is more than 3000 centistokes, the molding aid cannot easily be supplied to a nozzle having a long flow path. In addition, the molding aid used for the purposes of the invention must have an absorption ratio of less than 100 mg / cm ² , preferably less than 30 mg / cm ² , with regard to the vulcanizable material to be used. This absorbance ratio is determined for the purposes of the invention in the following manner: One of the prepared to be used vulcanizable material vulcanized sheet (30 mm χ 30 mm χ 1 mm) is dipped for 45 hours at a temperature of 150 ⁰ C in the to use a molding aid The Plate is weighed before and after immersion. The weight difference divided by the total surface area of the plate before immersion gives the absorption ratio.

If the absorption ratio of the molding aid is too high, it is also difficult to fail one Forming and maintaining the discontinuous film of the mold material. In general, a Distribution of the layer of molding aid in a uniform thickness cannot be expected. Especially then. if the long-travel nozzle is set horizontally, the molding aid tends to flow predominantly in the upper region of the interface. if Therefore, if a molding aid with too high an absorption ratio is used, then in the range in Since it flows relatively little, the molding aid is absorbed by the molded product, resulting in a partial Drying of the molding aid leads. This partial drying is not switched off even if the supply of the molding aid is increased because the additional molding aid is not in the dried-up Area comes but predominantly occurs in the area in which the flow of the form aid occurs takes place more easily In addition, excess molding aid tends to be added to the area in which the flow takes place more easily tends to close the surface of the molded product spoil

The absorption ratio of some molding aids increases as a result of the chemical changes «) under the conditions of molding and vulcanization to values of more than 100 mg / cm ² . These molding aids cannot be used for the purposes of the invention even if the original absorption ratio is within the limits required by b5. In addition, the molding aid to be used for the invention must not gelatinize in the course of a mixing process.

The gelatinization of the molding aid under normal process conditions is determined by the following test: A mixture of 10 parts by weight of a molding aid and 1 part by weight of an organic peroxide is heated in a closed vessel equipped with a stirrer at a rate of about 10 ° C per minute up to 235 ° C and held at this temperature for 5 minutes. Then the viscosity (η \) of the resulting liquid is measured at 235 ° C. The original viscosity (ηο) of the molding aid even at 235 ° C is also measured. If the molding aid has a ji / tjo ratio of less than 30, it is considered non-gelatinizing for the purposes of the invention and it is expected that it will not produce a gelatinized film in a continuous process for at least several hours the inner surface of a nozzle with a long flow path. If the organic peroxide used is non-volatile, the heat treatment can be carried out in an open vessel. In the test described it is not always necessary to use the organic peroxide which is actually admixed with the vulcanizable material. Other typical peroxides, for example dicumyl peroxide, can be used without an error in the determination occurring.

In addition, the molding aid used for the purposes of the invention should be used under vulcanization conditions not boiling.

When the molding aid boils, bubbles appear on the surface of the vulcanized product generated pockmarks. When heavy boiling occurs, the lubricating and separating properties go of the molding aid is lost and the surface of the vulcanized product therefore becomes rough and in in extreme cases cracking occurs. However, a slightly boiling molding aid can be tolerated because gentle boiling does not significantly affect the surface of the product

The following classes of compounds are suitable and exemplary for use as molding auxiliaries?

1) Polyoxyalkylenes and their derivatives, random, block or graft copolymers of two or several alkylene oxides and their derivatives, the molecular weight of which is more than 120 and less than 100,000

2) polyhydric alcohols (including their corresponding dehydrated products) from 4 to 50 Carbon atoms, their alkyl esters or ethers,

3) Fatty acid alcohol amides with a total of more than 8 Carbon atoms obtained from fatty acids with 2 to 30 carbon atoms and alcohol amines with 1 to 30 Carbon atoms were obtained,

4) fatty acid amides with 8 to 90 carbon atoms,

5) fatty acids with 8 to 90 carbon atoms and their metal salts,

6) Esters of polycarboxylic acids with 6 to 22 carbon atoms and monoalcohols with 1 to 20 Carbon atoms,

7) phosphoric acid esters of alkyl alcohols with 3 to 30 carbon atoms,

8) polyesters with a molecular weight of more than 200 and less than 30,000,

9) metal nitrates and metal halides,

10) Polysiloxane compositions with a molecular weight of more than 2,000 and less than 100,000 and gelatinization inhibitors (which will be described in detail later).

11) Polysiloxane compositions with a molecular weight of more than 2,000 and less than 100,000 is, and an alkali or alkaline earth metal hydroxide or oxide.

These compounds are based on their physical properties and less on the basis of their chemical properties Properties selected based on their ability to meet the stringent physical requirements described to meet. Typical examples of these compounds are given below: ι ο

1) Polyoxyalkylenes and their derivatives, random, block or graft copolymers of two or more alkylene oxides and their derivatives, the molecular weight of which is more than 120 and less than 100,000; of the alkyl ether type, such as
Polyethylene glycol lauryl ether, alkyl aryl ether,

how

Polyoxyethylene nonylphenyl ether,
Alkylthioethers, such as polyethylene glycol stearylthioethers,
Alkyl esters, such as
Polyoxyethylene valley oil ester,
Polyoxyethylene rosin ester,
Sorbitan alkyl esters, such as polyoxyethylene sorbitan monopalmitate,
Polyoxyethylene sorbitan tristearate,
Polyoxyethylene sorbitan monooleate,
Phosphoric acid esters, such as

Polyoxyäthylendikresylphosphat, condensation products with amines, such as
'N, N-di (polyoxyethylene) -stearylamine,
Condensation products with amides, such as
Polyoxyethylene stearylamide,

Polyoxyethylene nonylbenzenesulfonamide, and the like;

2) polyhydric alcohols (including their dehydration products) having 4 to 50 carbon atoms and their alkyl esters or ethers;
polyhydric alcohols, such as sorbitan and saccharides, alkyl esters or ethers of polyhydric alcohols (including their dehydration products), such as dehydrated sorbitan palmitate, esters of polyhydric alcohols and fatty acids, such as mono- or diglyceride, of linear fatty acids, such as palmitic acid, stearic acid, or Resin acids such as rhodic acid, naphthenic acid, caproic acid esters of pentaerythritol and alkyl esters of sucrose, myristyl galactose ether and the like;

3) fatty acid alcohol amides with a total of more than 8 carbon atoms, which are formed from fatty acids with 2 to 30 carbon atoms and alcohols with 1 to 30 carbon atoms;
Laurylethanolamide, Stean! ^ F 1! ylolamide, Palmhy ^1, oxymethylethanolamide and the like;

4) fatty acid amides with 8 to 90 carbon atoms, such as

Stearic acid amide, oleic acid amide and the like;

5) Fatty acids with 8 to 30 carbon atoms and their metal salts, such as

Fatty acids such as stearic acid, oleic acid, palmitic acid and the like. Metal salts of fatty acids, such as Stearic acid, oleic acid, palmitic acid, lauric acid, 12-hydroxystearic acid and naphthenic acid and a metal such as Li. Cu, Be, Mg. Ca, Sr, Ba, Zn, Cd, Al, Ce. Ti. Zr. Pb, Cr. Mn. Co. Ni, Fe, Hg, Ag, Tl, Sn and the same;

6) Esters of polycarboxylic acids with 6 to 22 carbon atoms and monoalcohols with 1 to 20 Carbon atoms, like

Dibutyl phthalate, di-2-ethylhexyl phthalate,

Dinonyl phthalate, di-n-octyl phthalate,

Dibutyl sebacate, di-2-ethylhexyl adipate,

Tri-n-butyl citrate, tri-2-ethylhexyl trimellitate,

Tri-n-octyl trimellitate,

Tetra-2-ethylhexylpyromellitate

and the same;

7) Phosphoric acid esters of alkyl alcohols having 3 to 30 carbon atoms, such as

Tributyl phosphate, tri-2-ethylhexyl phosphate and like;

8) Polyesters with a molecular weight of more than 200 and less than 30,000, such as
Polyethylene succinate, polypropylene adipate,
Polyäthylcna / elat,

Poly (1,3-butanediol) sebacate,

Poly (diethylene glycol) adipate,

Poly (1,6-hexanediol) adipate,

Polyprcp; Phthalate and the like;

9) metal nitrates and metal halides, such as

BiCl ₃ , BiBr ₃ , AgNO ₃ , TlNO ₃ , mixtures of NaNO ₃ , KNO3 and Ca (NO ₃ ) ₂ and the like;

10) Mixtures of polysiloxanes with a molecular weight of more than 2,000 and less than 100,000 and gelatinization inhibitors (to be described in detail below), how

a composition of matter consisting of liquid organopolysiloxane, such as polydimethylsiloxane, Polymethylphenylsiloxane, and an inhibitor. If polysiloxane is used alone as a molding aid is, the gelatinization of the polysiloxane occurs in a short time during vulcanization. However, polysiloxane can be used as a satisfactory molding aid if it is a Inhibitor is added, which reacts with the organic peroxide and the crosslinking of the polysiloxane prevented by the peroxide. Examples of these inhibitors include phenols and amines, such as a-naphthol, / S-naphthol, pyrogallol, catechol, 4,4'-thio-bis (6-t-butyl-m-cresol), 1,2-dihydro-2,2,4-trimethylquinoline (and its polymerization products), bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, Dinaphthyl-p-phenylenediamine hydroquinone and the same. The amount of the inhibitor to be added to the polysiloxane is in generally in the range of 5 to 30 parts by weight, preferably 10 to 20 parts by weight, per 100 Parts by weight of the polysiloxane.

11) Compositions of substances consisting of polysiloxanes having a molecular weight of more than 2,000 and less than 100,000 and an alkali metal Alkaline earth metal hydroxide or oxide, such as

a mixture of polysiloxane and a metal oxide, such as calcium oxide, or metal hydroxides, such as Potassium hydroxide, sodium hydroxide, lithium hydroxide and the like. That the form help center! mixed metal hydroxide or oxide has the function of the degree of polymerization of the polysiloxane to be reduced by hydrolysis. In this way, the crosslinking is acted upon of the organic peroxide caused increase in the degree of polymerization of polysiloxane compensated Such a composition of matter can be used in a satisfactory manner for the purposes of

Invention can be used as a molding aid. The amount of to be added to the polysiloxane Metal hydroxide or oxide generally ranges from 1 to 10 parts by weight, preferably from 3 to 7 parts by weight, per 100 parts by weight of the polysiloxane. Among the many used in the present invention Molding auxiliaries are preferably polyoxyalkylenes and their derivatives, random, block or Graft copolymers of 2 or more alkylene oxides and their derivatives, and aliphatic polyesters, used.

A molding aid that is a solid or a highly viscous liquid can be in the form of the melt or in the form of a mixture with a suitable liquid, for example Alky'bcnzcl, used will. Such a mixture must of course meet the above physical requirements for the Meet mold auxiliaries.

Synthetic polymers suitable for the purposes of the invention are addition polymers, such as homo- or Copolymers of olefins, diolefins, vinyl esters, vinyl ethers, vinyl ketones and other vinyl or Vinylidene monomers. Further examples of synthetic polymers are polyamides, thermoplastic polyesters and polyorganosiloxanes. Polymers such as

Polyethylene, ethylene-propylene copolymers, Ätlij.vin-propylene-diene terpolymers, Ethylene vinyl acetate copolymer,

Ethylene-ethyl acrylate copolymer, styrene-butadiene copolymer,
Polycis-1,4-isoprene, polychloroprene, polybutadiene, polydimethylsiloxane or polyphenylmethylsiloxane.

However, any synthetic polymer can be used to carry out the method according to the invention can be used, which can be vulcanized with the help of an organic peroxide.

Examples of suitable organic peroxides are dialkyl peroxides, such as

Dimethyl peroxide, methyl ethyl peroxide, diethyl peroxide, 1,1-dihydroxydiethyl peroxide, ethyl cyclohexyl peroxide, propylhexyl peroxide, di-tert-butyl peroxide, di-n-butyl peroxide, tert-butyl-tert-amyl peroxide,
tert-butyl-phenol-methyl peroxide, tert-butyl vinyl peroxide,
tert-butylcumyl peroxide,

Dichloro-tert-butyl peroxide, di-tert-pentyl peroxide,
tert-Pentyl-tert-hexyl peroxide, di-n-hexyl peroxide, di-tert-hexyl peroxide, dicyclohexyl peroxide, di-n-heptyl peroxide, diphenyl-methyl-9-xanthenyl peroxide, dicumyl peroxide, 1,1'-di-tert-butyl peroxyethane, 2.2 -Bis (tert-butyIperoxy) butane, 1,4-bis (cumylperoxy) butane,
1,10-bis (cumylperoxy) decane,

2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (tert-burylperoxy) -3-hexyne, 1,3-bis (tert-butylperoxy) diisopropylbenzene, 1,4-bis (tert-butylperoxy) diisopropylbenzene and the same,

Hydroperoxides, such as 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethylhexin-2,5-dihydroperoxide and the same;

Peroxy acids and their esters, such as
tert-butyl peroxybenzoate,
Di-tert-butyl diperoxyphthalate,
2,5-di (benzoylperoxy) hexane and the like.

Mixtures of the organic peroxides mentioned can also be used in the process according to the invention will.

The specified organic peroxides can be added to the vulcanizable material in an amount of 0.05 to 10 parts by weight per 100 parts by weight of the synthetic polymer. The vulcanizable materials used for the process according to the invention can contain various additives, such as antioxidants. Vulcanization accelerators, vulcanization retarders, other vulcanization auxiliaries. Stress stabilizers, plasticizers, color pigments, carbon black or dyes. Examples of antioxidants that can be used are 4,4'-bis (3-methyl-6-tert-butylphenol), N, N'-di-2-naphthyl-p-phenylenediamine. Examples of suitable vulcanization accelerators are ρ, ρ'-dibenzoylquinone dioxime, tetramethylthiuram disulfide. Examples of vulcanization retarders are 2,6-di-tert-butyl-p-cresol, phthalic anhydride. Examples of other vulcanization auxiliaries are triallyl isocyanurate and diallyl phthalate. Examples of saving stabilizers are 9,10-Dibromanthract: n, DipUeuyid ^ iP-l N ₁ N'-Dialkylkupferdithiocarbarriaii.

For a better understanding of the inventive method should el. .Iliegenden serve ^l drawings which illustrate schematic diagrams of specific embodiments of the invention. In these drawings shows

F i g. 1 is a longitudinal section of an apparatus for manufacturing an electrical cable with vulcanized Insulation layer and

2 shows a longitudinal section of a device for Manufacture of a tube from vulcanized polymer.

In Fig. 1 shows a nozzle 3 with a long flow path, which by means of a nozzle holder 7 is connected to the Cross-head 1 of an extruder is connected and which consists of the nozzle parts 31, 32 and 33, which through Flanges are connected to one another in a row and can therefore be disassembled into individual parts.

The flange 4, which is screwed onto the end of the nozzle part 31, forms an annular recess 47 and an annular projection 46. This annular recess 47 results in a step 48. In this recess 47 is a porous tube 41 inserted The inner diameter of the nozzle part 31, des The protrusion 46 and the porous tube 41 are the same. An annular chamber 42 surrounds the porous tube 41. This chamber 42 is connected to a bore 44 in the flange 45, and the bore 44 is via a Connecting part 45 connected to a line 43.

A flange 4 'of the nozzle part 32 is hermetically sealed with the aid of bolts 49 and nuts 50 Flange 4 attached. The molding aid is removed from a molding aid container through line 43 and bore 44 (which is not shown) with the help of a high pressure pump (not shown), such as a multiple piston pump, in particular a Bosch-type pump, inserted into chamber 42

The chamber 42 serves as a storage container for the molding aid. The mold tool that is included in the Chamber 42 is filled, seeps out of the porous tube 41. The molding aid spreads from the inner surface of the porous tube 41 on the entire inner surface of the subsequent part of the long-path nozzle and facilitated

through the smooth passage of a molded product the channel of the nozzle with long flow away 3.

The molding aid is fed to the inner surface of the nozzle in the area of the entry into the nozzle channel, preferably it is fed within 1 m of the entry into the nozzle channel. The entry area of the nozzle channel of the long flow path nozzle is maintained at a temperature high enough to melt a vulcanizable material to be deformed, but low enough to prevent premature vulcanization (this area is hereinafter referred to as the deformation zone ). The subsequent portion of the nozzle with a long flow path is maintained at a temperature high enough;? SL to the material \> vulcanize The heating this zone success' by means of a nozzle with a long flow path surrounding band heater 6 (this area is hereinafter referred to as Vulcanization zone). The length of the deformation zone is not subject to any restriction, but is preferably less than ¹ m. The deformation zone can be restricted to the actual entry of the nozzle channel of the nozzle with a long flow path.

A molten vulcanizable material R is extruded by means of an extruder, not shown, on an electrical conductor W , which is continuously introduced into a "cross-die head through a guide part 2, and is deformed to form predetermined dimensions while the deformation zone of the nozzle with a long flow path The molded layer on the electrical conductor IV is heated and vulcanized while passing through the vulcanizing zone of the nozzle with a long flow path, and is fed into a water-cooled device 5 directly connected to the nozzle part 33 after exiting the nozzle. There, water is continuously supplied and discharged under high pressure, for example of about 30 kg / cm ² , in the direction of the arrow shown in FIG.

It has surprisingly been found that the formation of cavities or bubbles in the insulating layer is negligibly small if a cable insulation after the exit of the cable from the nozzle with long flow path is immediately cooled in pressurized water.

It was found that a vulcanizate obtained by steam distillation shows numerous micro voids when observed under a microscope. It has also been found that in conventional steam vulcanization, which is mostly carried out at a pressure between 15 and 20 kg / cm ² , a cooling water pressure of more than about 10 kg / cm ² has little effect on the number of cavities in the Isolation occur.

In contrast, it was found that the vulcanizate obtained according to the invention has no voids when the cooling is carried out at a pressure of more than 10 kg / cm ² .

All of these observations were made under a differential interference microscope to identify cavities to be able to distinguish clearly from the insulating material.

Void-free insulation, which was believed to be ideal for high voltage cables, was able to get through the method according to the invention can now be implemented for the first time.

Networking a device for making a pipe! Polymers! is in the accompanying Fig. 2 shown. In Fig. 2, the vulcanizable material R is extruded into the channel of the attachment (adapter) 1 with the aid of an extruder and, after passing through the passages of the branches 7 of the distributor 3, is deformed into a cylindrical shape in the area of the inlet of a nozzle with a long flow path 4. At this stage, the temperature of the vulcanizable material is still below its vulcanization temperature. The vulcanizable material thus formed is then heated and vulcanized as it moves through the annular channel (vulcanization zone) enclosed by the long flow path nozzle 4 and the long mandrel 5. The molding agent is fed both to the inner surface of the nozzle with a long path 4 through the porous tube 10 in the manner described in connection with FIG the mandrel 5 is inserted and attached. This mandrel 5 is screwed onto the distributor 3 and extends as far as the exit of the cooling device 6. To feed the molding aid onto the mandrel 5, this is the molding aid center! through channel 16 and Bohr mg 17 in the same way as in FIG. 1 is inserted into the annular chamber 12. The mandrel 5 is heated to the vulcanization temperature with the aid of the heating cartridge 19 inserted into the mandrel. The hay cartridge 19 is connected to a power source via the lead wires 18. After the vulcanized tube has emerged from the outlet of the nozzle with a long flow path 4, it is cooled under pressure in the cooling device 6, which is directly connected to the nozzle with a long flow path 4, for example at about 10 kg / cm ² . The up to the exit of the cooling device 6 in the in F i g. The mandrel 5, which extends in the manner shown in FIG. 2, serves to prevent the tube from being deformed by the pressure of the cooling medium. However, a mandrel 5 can also be used which extends only as far as the exit of the nozzle with long flow path 4, provided that the deformation of the vulcanized pipe by the pressurized cooling medium is permissible or that there is no risk of deformation of the pipe by the pressurized cooling medium exists. To produce a vulcanized product free of bubbles or voids, a pressure of the cooling medium of 5 to 50 kg / cm ² , preferably 5 to 30 kg / cm ² and in particular 20 to 30 kg / cm ^{2 is} recommended. It is also preferred to use a cooling device 5 which is constructed so that it can be easily moved, for example

so by using wheels attached to it. With the help of this design it is more convenient to increase the number of To reduce or increase nozzle parts or to replace the nozzle parts and, moreover, the Cooling device itself depending on the thermal expansion of the nozzle with a long flow path 3 Due to temperature changes. In the method according to the invention, in Depending on the cross-section and size of the desired product, you can choose between long nozzles Flow path of different cross-sectional shapes and dimensions used. It is possible that this Nozzles with a long flow path are composed of two or more nozzle parts which are shown in FIG. 1 illustrated manner are connected in series. As a material for the nozzle with a long flow path materials with good thermal conductivity such as iron, brass, copper or aluminum are preferred used. The nozzle with a long flow path can after

can be heated in numerous ways, for example with the help of an electric one placed around the nozzle Heating band, with the help of a jacket arranged around the nozzle and heated with hot oil direct supply of electrical current to the wall of the nozzle or by induction heating. The nozzle The long flow path is usually 1 to 20 m or longer if necessary.

The term "nozzle with a long flow path" is used for a nozzle with a long nozzle channel that is used in the English is referred to as "the juggling country".

The method of applying molding aid to the inner surface of the nozzle with long flow path can be freely may be selected provided that the molding aid supplied extends over the entire inner surface of the nozzle is distributed with a long flow path or at least over the entire inner surface of its vulcanization zone. It It is believed that the use of a porous tube as shown in FIG. 1 shown is the best Possibility of supplying the molding aid; However, it may also be the application of another Method may be possible, such as supplying the molding aid through an in the nozzle with a long flow path provided slot.

The molding aid is usually supplied in the deformation zone with a long flow path, however, the deformation zone is extremely short, see above it takes place at the inlet opening of the nozzle with a long flow path. Additional feeding is also possible. For example, the additional introduction can take place at a predetermined point in the vulcanization zone. This additional introduction of molding aids is preferably carried out in the bottom part of the horizontal arranged nozzle with a long flow path, because this area tends to dry out.

With the kind of the molding aid, the size of the molded products, and the molding and vulcanization conditions, the rate of supply of the molding aid varies; however, it is usually in the range of about 0.001 to 0.04 cm ³ per 1 cm ^{2 of} the surface of the molded product.

The temperature conditions during deformation and vulcanization and the cooling conditions with regard to the pressure of the cooling medium depend on the vulcanizable materials to be used. For example, when using polyethylene is low density with a content of dicumyl peroxide, the pressure of the cooling medium in the range of about 5 to 50 kg / cm ^2, the temperature of the deformation zone in the temperature range of about 110 to 14O ⁰ C and the temperature of the vulcanization zone in the range of about 150 to 300 ° C selected. Generally, the pressure are de Kühimediums ^c, the temperature of the deformation zone and the temperature of the vulcanization zone in the range of 5 to 50 kg / cm ^2, 100 to 150 ⁰ C and 140 to 300 ° C.

In the method according to the invention, the deformed product can before it enters the vulcanization zone occurs, are coated with a layer that does not contain any organic peroxide. This can be done by suitable means, for example with the aid of an extruder, take place. The applied layer prevents that direct contact of the molding aid with the organic peroxide emerging from the molded product and therefore reduce the risk of destruction of the e: Mold aid by the organic peroxide.

As covering materials it is advantageous to use poly others thermoplastic polymers used to manufacture an electrical cable with a vulcanized Overcoat layer, this overcoat layer can be a semiconducting layer. Coating layers of a Thicknesses of 0.5 to 1 mm are usually sufficient to allow the molding aid to come into contact with the organic To prevent peroxide.

The invention makes it possible to use vulcanization with the aid of a nozzle with a long flow path Applicable for the first time, and it can vulcanized objects with good surface finish in can be produced in a more efficient and economical manner. The invention is also suitable Method particularly good for manufacturing insulated high-voltage cables because the manufactured vulcanized insulation is free of voids and bubbles

The process according to the invention is described below using examples.

example 1

A vulcanizable polyethylene, consisting of 100 parts by weight of low-density polyethylene with a density of 0.920 and a melt index of 0.5 (according to ASTM D 1238-1970. Method A, Condition E), 2.0 parts by weight of dicumyl peroxide. 0.5 part by weight of 4,4'-thio-bis (3-methyl-6-t-butylphenol) and 0.25 part by weight of diallyl phthalate, was fed into an electrically heated extruder (cylinder channel: 120 mm, IVD: 14, compression ratio: 2) and extruded onto a cable core which was continuously fed into the crosshead of the extruder at a linear speed of 3.5 m / min. The cable core had a vulcanizable, semiconducting polyethylene layer with a thickness of 1 mm on a strand (diameter 600 mm ² ) made of 91 copper wires, the outer diameter was 2.9 mm.

A nozzle with a long flow path with a length of 6000 mm and an inner diameter of 69.9 mm was attached directly to the exit of the cross-head, and the deformation zone (500 mm) was at 130 ⁼ C, the Vuikariisaiionzone (remaining 5500 mm) was at 250 ⁰ C held. A molding aid feeder was placed 100 mm from the end of the long flow path nozzle which was adjacent to the crosshead. As a molding aid, a ethylene oxide-propylene oxide block copolymer has (a molding aid 1), the following data was: Density (ρ) 1.05 at 20 ⁰ C, refractive index (nl °): 1.459. Viscosity: 5.76 centistokes at 235 ° C, boiling point: more than 300 ⁰ C, ηι / ηο: below 2, absorption ratio: - 0.15 mg / cm ² (note 1). This molding aid was continuously fed through the feeder at a rate of 1.5 cm ^J / min (0.012 cm ³ per 1 cm ^{2 of} the surface of the extruded product) using a high pressure piston pump. The non-vulcanizable polyethylene was extruded onto the cable core and deformed as it passed through the deformation zone and then heated and vulcanized as it passed through the vulcanization zone. After passing through the nozzle with a long flow path, the cable, insulated with vulcanized polyethylene, was cooled ^{with the aid of high-pressure cooling water of 25 kg / cm 2.} In this way, a vulcanized polyethylene-covered cable (thickness

18 mm), which had a glossy surface (Grade No. 1, Note 2). In no area of Cable insulation voids were found (Note 3).

Examples 2 to 24

The deforming and vulcanization of insulating materials on a cable core was carried out according to the invention Procedure carried out under the conditions shown in Table 1. the number of Voids in the insulating layer were determined according to the method of Example 1 (Note 3) No voids were found in the cable insulation made according to each example became. The duration of the continuous implementation of the process and the nature of the surface of the insulating layer of the cable according to each of the examples are shown in Table 1.

Remarks:

1. It is assumed that the negative value of the absorption ratio is due to the extraction of certain additives from which polyethylene is caused into the molding aid.

2. The surface of the vulcanizate is made in the following manner rated: rating

No. 1: Shiny

No. 2: Shiny but slightly cloudy

No. 3: Not shiny, but with a smooth handle

No. 4: Honeycomb-shaped fine cracks

3. The determination of the number of voids in the insulating layer was made as follows: One The test piece cut from the insulation layer is cooled in liquid nitrogen for 30 minutes, then the Cut the piece into slices about 10 microns thick using a microtome. The number of cavities in the Disc is counted under an optical microscope (differential interference type microscope, 300 times Enlargement).

Tabel Ί b
mm C.
el c2 c3 Molding aid
d e
cSt /
⁰ C G A.
mg / cm- ' i
cc / cm ² NJ
t — k
CT> H-*.
OO at
game
No. Structure of the electric cable
a 18th LDPE
(ο: 0.920,
MI: 0.5) DCP
2.0 parts 4,4'-thiobis- (3-me-
ethyl-6-t-butyl-
phenol) 0.5 parts
Diallyl phthalate
0.25 parts Molding aid 2 28.00 300 < 2> -0.82 0.01 [ 560 2 Copper strand (91/2.9 mm, diam
diameter: 600 m ² covered) with
vulcanized semi-conductive
Polyethylene layer (1 mm thick) 18th LDPE
(ρ: 0.920,
MI: 1.0) TBCP
2.5 parts 4,4'-thiobis- (3-me-
thyI-6-t-butyl-
phenol) 0.3 parts
p.p'-dibenzoylquinone-
dioxime 0.5 parts Molding aid 2 8.96 300 < 2> -1.03 0.011 3 dito 18th EVA
(ρ: 0.93,
MI: 3.5,
VAc content:
14% weight%) TBCP
2.5 parts 4,4'-thiobis- (3-me-
ethyl-6-t-butyl-
phenol) 0.3 parts
p, p'-dibenzoylquinone-
dioxime 0.5 parts Molding aid 2 4.42 300 < 2> -1.08 0.015 4th dito 18th LDPE
(ρ: 0.920,
MI: 0.5) BBPB
3.0 parts N, N'-dinaphthyl-
p-phenylene diamine
0.5 parts
p, p'-dibenzoylquinone-
dioxime 0.2 parts Nonylphenyl
polyoxyethylene *) 1.98 245 < 2> 0.35 0.65 5 Copper strand (91/2.9 mm, diam
knife: 600mm ² ) covered with
vulcanized semi-conductive
Polyethylene layer (1 mm thick) 17th LDPE
(ρ: 0.920,
MI: 0.3) TBCP
2.0 parts Triallyl iso-
cyanurate 1.0 parts
Phthalic acid
anhydride 0.8 parts Oleic acid amide **) 1.17 350 < 2> 0.85 1.65 '6 Copper strand (37 / 2.6 mm, diam
diameter: 600 m ² covered) with
vulcanized semi-conductive
Polyethylene layer (1 mm thick) 17th dito dito dito Stearic acid ***) 1.13 360 < 2> 0.92 1.86 7th dito 16 LDPE
(ρ: 0.920,
MI: 1.0) BBPB
2.0 parts Triallyl iso-
cyanurate 2.0 parts
2,6-di-t-butyl-
paracresol 0.5 parts Polydimethyl
siloxane
(200OcSt at 3O ⁰ C)
100 parts
Pyrogallol 20 parts 141 400 < 3.5 1.18 3.2 8th Copper strand (19 / 2.6 mm. Dia
knife: 100mm ² ) covered with
vulcanized semi-conductive
Polyethylene layer (1 mm thick) 16 LDPE
(ρ: 0.920,
MI: 1.0) DCP
2.0 parts Triallyl iso-
cyanurate 2.0 parts
ρ, ρ'-dibenzoylquinone-
dioxim 0.7 parts Polydimethyl
siloxane
(200OcSt at 30 ⁰ C)
100 parts
KOH 5 parts 132 400 < 3.8 3.56 6.4 9 Copper strand (19 / 2.6 mm, diam
knife: 100mm ² ) covered with
vulcanized semi-conductive
Polyethylene layer (1 mm thick)

To continue

example
No. a

Structure of the electric cable

C.
el c2 c3 Molding aid e
cSt ■ F
⁰ C G H
mg / cm- ¹ i
cc / cm ³ b
mm LDPE
(ρ: 0.920,
Ml: 0.3) TBCP
2.5 parts Triallyl iso-
cyanurate 2.0 parts
Tetramethylthiuram
dilsufid 0.7 parts d 12.8 270 < 2> 0.78 0.32 17th dito DCP
2.5 parts Triallyl iso-
cyanurate 2.0 parts
4,4'-thiobis (3-methyl-
6-t-butyl-
phenol) 0.5 parts Poly (1,6-hexane
diol adipate) 2.13 260 < 2> 3.62 1.43 13th LDPE
(o: 0.920,
MI: 0.3 DCP
2.5 parts Triallyl iso-
cyanurate 2.0 parts
4,4'-thiobis (3-methyl-
6-t-butyl-
phenol) 0.5 parts Sorbitan
monolaurate 3.62 270 < 2> -0.20 0.32 13th Polyoxyethylene
sorbitan monolaurate

Copper strand (37 / 2.6 mm, diameter: 200 mm ² ) covered with a vulcanized, semi-conductive polyethylene layer (1 mm thick)

Copper strand (7 / 2.0 mm, diameter: 22 mm ² ) covered with a vulcanized, semi-conductive polyethylene layer (1 mm thick)

Copper strand (7 / 2.0 mm, diameter: 22 mm ² ) covered with a vulcanized, semi-conductive polyethylene layer (1 mm thick)

dito

dito

Copper strand (19 / 2.6 mm, diameter: 100 mm ² ) covered with a vulcanized, semi-conductive polyethylene layer (1 mm thick)

13 ditto ditto ditto

13 ditto ditto ditto

16 EPDM DCP zinc white 5.0 parts

3.0 parts of poly (2,2,4-trimethyl-1,2-dihydroquinone) 1.5 parts MT carbon 12.5 parts chemically pretreated clay 125 parts P-200 paraffin oil 2.0 parts

Minimum 5.0 parts paraffin wax 5.0 parts laurylethanolamide 1.26 260 <2>

1.61

0.69

Tetra-n-octyl pyromelitate

Molding aid 1

1.67 250 <2>

5.73 300 <2>

25.2 0.73

-0.15 0.012

continuation

example
No. ti

Structure of the electric cable

b mm

Form tools!
d

c2

c3

Λ i

mg at ² cc / cm- '

Copper strand (19 / 2.6 mm, diameter: 100 mm ² ) covered with a vulcanized, semi-conductive polyethylene layer (1 mm thick)

Copper strand (19 / 2.6 mm, diameter ^{100 mm 2} ) covered with a vulcanized semi-conductive polyethylene layer (1 mm thick)

dito

Copper strand (19 / 2.6 mm, diameter: 100 mm ² ) covered with a vulcanized, semi-conductive polyethylene layer (1 mm thick)

dito

16

16

16

16

16

SBR DCP Zinc white 5.0 parts molding aid 1 Molding aid 3 3.0 parts Poly (2,2,4-trimethyl- 1,2-dihydro- quinone) 1.0 part Stearic acid 2.0 parts MT Carbon 50 parts Dibenzothiazyl disulfide 1.25 parts Calcium carbonate 37.5 parts Paraffin wax 3.0 parts Mixture of Polycis DCP Zinc white 3.0 parts Glycerine and poly- 1,4-isoprene 2.0 parts Poly (2,2,4-trimethyl-
1,2-dihydro-
quinone 0.75 parts propylene adipate Stearic acid 1.0 part (1: 1) N-phenyl-N'-iso- propyl-p-phenylene- Mixture of diamine 0.75 parts Molding aid 1 Lead dimethyl and dioctyl sebacate
(1: 1) dithiocarbamate Mixture of 0.3 parts Sorbitan mono- 4,4'-thiobis (3-methyl- laurate and LDPE dito 6-t-butyl- Stearic acid (1: 1) (ρ: 0.92, phenol) 0.5 parts MI: 1.0) Diallyl phthalate 0.25 parts 4,4'-thiobis (3-methyl- LDPE DCP 6-t-butyl- (ρ: 0.92, 2.0 parts phenol) 0.5 parts
Diallyl
phthalate 0.25 parts MI: 1.0) dito dito dito

5.73 300 <2> -3.18

0.012

8.96

300 <2>

-1.07

0.012

7.1

290 <2>

3.52 250 <2>

1.83

64

0.36

20.5

1.8

260 <2>

3.3

0.74

Structure of the electric cable J ™ b egg c2 m c3 ra2 Molding aid • f 8 Hi K) KJ K) mm LDPE DCP ml 4,4'-thiobis (3-methyl- ⁰ C ⁰ C mg / cm ² cc / cm ² continuation a mm mm 16 (ο: 0.92, 2.0 parts mm 6-t-butyl- 250 d e 255 <2> 35.5 17.6 at 6,000 69.9 Μ1: Ί, 0) 5,500 phenol) 0.5 parts 250 cSt game Copper strand (19 / 2.6 mm, diam 6,000 69.9 5,500 Diallyl 250 80% solution of 0.65 Wl No. knife; 100 mm ² ) covered with 10,000 69.9 9 500 phthalate 0.25 parts 250 Oleic acid amide in O vulcanized semi-conductive 10,000 69.9 9 500 250 Alkylbenzene 21 Polyethylene layer (1 mm thick) 20,000 54.2 LDPE DCP 19 700 4,4'-thiobis (3-methyl- 250 Viscosity 13 cSt 20,000 54.2 16 (ο: 0.92, 2.0 parts 19 700 6-t-butyl- 260 at 30 ° C and 250 <2> 11.0 5.3 10,000 47.0 MI: 1.0) 9,990 phenol) 0.5 parts 260 nl °: 1.487 Copper strand (19 / 2.6 mm, diam 10,000 47.0 9,990 Diallyl 270 80% solution of 0.71 knife: 100mm ² ) covered with 3,000 '54.2 2,800 phthalate 0.25 parts 250 Magnesium stearates vulcanized semi-conductive 3,000 33.0 dito dito 2,700 dito in triamylamine 22nd Polyethylene layer (1 mm thick) 16 LDPE dito dito 260 <2> 8.31 4.0 18th (ο: 0.920, 320 <2> -0.08 0.012 dito MI: 0.1) Tri-n-butyl citrate 0.68 Copper strand (91/2.9 mm, diam Molding Aids 5,348 knife: 600mm ² ) covered with 23 vulcanized semi-conductive 24 Polyethylene layer (1 mm thick) Duration of the surfaces Table 1 (continued) continuous nature Example nozzle with a long flow path / / 2 Procedure No. /1 ⁰ C execution mm 130 ο ρ hours 500 130 300 < 1 500 125 cm / min. kg / cm ² 250 < 2 2 500 125 35 25 250 < 2 3 500 125 35 25 200 < 3 4th 300 125 55 25 100 < 3 5 300 130 55 25 100 < 3 6th 10 130 112 25 20 < 1 7th 10 125 114 25 25 < 2 8th 200 130 61 25 100 < 2 9 300 61 25 70 < 3 10 28 22 11th 21 20

miBi ^

• OrtsetzLing

Example no.

Long flow path nozzle jk

/1

mm

/ 2 ⁰ C

ml

mm

m2 ⁰ C

cm / min

P kg / cm ²

Duration of the
continuous
Procedure
execution surfaces
nature hours 80 < 2 100 < 2 100 < 3 50 < 1 45 < 1 45 < 2 150 < 3 25 < 2 25 < 2 25 < 3 25 < 3 20 < 3 600 < 1

12 13 14 15 16 17 18 19 20 21 22 23 24

3 3 3 3 3 3 3 3 3 3 3 3 6

33.0 33.0 33.0 47.0 47.0 47.0 47.0 47.0 47.0 47.0 47.0 47.0 69.9

300 300 300 200 200 200 200 200 200 200 200 200 500

130 130 130 130 130 130 130 130 130 130 130 130 130

2 2 2 2 2 2 2 2 2 2 2 2 5

Note: The symbols in the table have the following meanings:

a: cable core

b: Thickness of the insulating layer applied to the cable core (mm)

c: Composition of the vulcanizable to be applied to the cable core Materials

el: synthetic resin (ρ: density, MI: melt index (ASTM D 1238-1970, method A, condition "E), VAc: vinyl acetate)

c 2: organic peroxide

c3: other additives

d: Art

e: Viscosity (v ₀₎ (centistokes at 235 ⁰ C)

/: Boiling point ( ⁰ C)

g ". V \ / V0

h: absorption ratio at 150 ° C, 45 hours (mg / cm ² )

/ ': Feed rate (cmVcm ^{2 of} the outer surface of the insulating layer)

j: length of the nozzle channel (mm)

k: inner diameter (mm)

/: Deformation zone

/ 1: length (mm)

12: temperature ("C)

m: vulcanization zone

ml: length (mm)

m2: temperature ( ⁰ C)

o: feed speed of the cable core (cm / min)

p: pressure of the cooling water (kg / cm ² )

250
250
250
210
210
210
210
210
210
210
210
210
250

DDTBH:

21
21
21
48
45
47
47
47
47
47
47
47
35

20 20 20 18 18 18 18 18 18 18 18 18 25

Low density polyethylene

Ethylene vinyl acetate copolymer

Ethylene-propylene-diene terpolymer

Dicumyl peroxide

t-buticumyl peroxide

1,3-bis (t-butylperoxy) diisopropylbenzene

2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3

Molding aid 1:
Molding aid 2:

Molding aid 3:
Molding aid 4:
Molding aid 5:

Ethylene oxide-propylene oxide block copolymer (ο: 1.05 at 2O ⁰ C,

nl °: 1.459)

Ethylene oxide-propylene oxide block copolymer (Q: 1.061 at 2O ⁰ C,

nf: 1.462)

Copolymer in which ethylene oxide is graft copolymerized is grafted onto polypropylene oxide (average molecular weight: 3300)

Copolymer in which ethylene oxide is graft polymerized is grafted onto polypropylene oxide (average molecular weight: 2200)

Ethylene oxide-propylene oxide block copolymer (ρ: 1.095 at 2O ⁰ C, n $: 1.466)

*) That which is withdrawn from the interface between the nozzle and the product at the end of the nozzle Molding aid boiled slightly before attaching the cooler to the nozzle end.

* *) ***) This form aids were melted by the feeders were kept for the molding aid at 100 ⁰ C, and then supplied.

Example 25

A vulcanized cable was produced in the manner described in Example 1 with the modification that polyoxyethylene stearylamide instead of molding auxiliary 1 and di-t-butyl peroxide instead of DCP was used. The process was carried out continuously for 60 hours.

Example! 26th

An insulated cable was produced in the same manner as in Example 11 except that sorbitan was used in place of sorbitan monolaurate. Molten Sorbitan was supplied by the Zufiihrungsvorrichtung was maintained for the molding aid at 160 ⁰ C. Continuous operation was achieved for 60 hours with grade 3 surface finish.

Example 27

An insulated cable was manufactured in the same manner as in Example 14 except that Dibutyl phthalate instead of tetra n-octyl pyromellitate was used. The process could be carried out continuously for 40 hours, with a surface finish corresponding to Grade No. 3 was obtained.

Example 28

A 3000 mm long nozzle with a long flow path and an inner diameter of 25.8 mm was connected to the outlet of the longitudinal head of a piston extruder. The 300 mm long forming zone was maintained at 150 ⁰ C and the subsequent 2700 mm long vulcanization zone was heated to 200 ⁰ C. This extruder was a mixture of 1.0 part by weight of 2,5-dimethyl-2,5-di (t-butylperoxy ) hexyne-3, 1.0 part by weight of N, N'-di-2-naphthyl-p-phenylenediamine and 100 parts by weight of high-density polyethylene (ρ: 0.965, melt index MI: 0.2 [ASTM D 1238-1970, method A, Condition F]) fed to a vulcanized

Table 2

Manufacture of high-density polyethylene rod with an outside diameter of 25.8 mm at a speed of 33 m / min. Shape help center! 1 was delivered to the outer surface of the product at a rate of 0.01 cnvVcm ^2. Continuous operation of the process was ensured for 120 hours, with a grade No. 1 surface finish being obtained.

Example 29

Using an apparatus shown in Fig. 2, a vulcanizable polyethylene composed of 100 parts by weight of high density polyethylene having a density of 0.96 and 2 parts by weight of dicumyl peroxide was extruded from the extruder into a long flow path nozzle 4 (5000 mm long). At the entrance of the nozzle 4, molding aid 1 was fed to both the inner surface of the nozzle 4 and the outer surface of the mandrel 5 ^{at a rate of 0.015 cmVcm 2 of the surface of the molded product.} While the molded product moved through the die with long flow path 4, it was vulcanized at a temperature of 230 ⁰ C. The vulcanized product was then cooled in the cooling device 6 (length 5000 mm) under a pressure of 15 kg / cm ^2. An excellent vulcanized polyethylene pipe was formed, the wall thickness of which was 4 mm and the outer diameter of which was 400 mm.

Comparative Examples 1 to 6

The deformation and vulcanization of insulation materials on cable cores was carried out under the conditions shown in Table 2 conditions shown. In Comparative Example 1 was for 3 hours after the start of An insulated cable with a good surface finish (grade No. 1) was obtained, after which it was made however, the surface of the cable gradually became rough and finely cracked about 10 minutes later. Pieces of gelled film of the molding aid (silicone oil) were on the cracked surface of the Product. In Comparative Examples 2 to 6, only products with severely cracked surfaces were obtained.

Comparison
example Structure of the electric cable b C. c2 c3 a c \ TBCP Triallyl isocyanurate 1.0 part 1 12th LDPE 3.0 parts Tetramethylthiuram disulfide Copper braid (19 / 2.0 mm, cross (ρ: 0.920 0.5 parts cut 60 mm ² ), coated with MI: 0.5) vulcanized, semiconducting dito dito 2 Polyethylene layer (1 mm thick) 12th dito TBCP Triallyl isocyanurate 1.0 part 3 dito 12th LDPE 3.0 parts Tetramethylthiuram disulfide Copper braid (19 / 2.0 mm. Cross (ρ: 0.920 0.5 parts cut 60 mm ² ), coated with MI: 0.5) vulcanized, bisecting dito dito 4th Polyethylene layer (1 mm thick) dito dito dito dito 5 dito dito dito dito dito 6th dito dito dito dito

Table 2 (continued)

Comparative molding agent
example

H
mg / cm ²

ι
cc / cm ²

Polydimethylsiloxane (2000 cSt

at 30 ⁰ C)

castor oil

Eugenol

water

Paraffin oil

Soap solution (25% aqueous

Solution of potassium soap from

Soybean oil)

400 <

Table 2 (continued)

2.39

1.36

2.56 300 < 2> 200 30.5 0.38 250 < 2> 17th 10.8 100 2> -032 1.2 2.55 300 < 51 120 7.5 110 2> 1.8 1.25

VergL nozzle with a long foot path
Example jk 1

mm mm mm

/ 2

⁰ C

ml

mm

m2
⁰ C

ο
cm / min

P.
kg / cm ²

Duration of the continuous process management
hours

1 3000 36.0 200 125 2800 250 41 25th 2 3000 36.0 200 125 2800 250 41 25th 3 3000 36.0 200 125 2800 250 41 25th 4th 3000 36.0 200 125 2800 250 41 25th 5 3000 36.0 200 125 2800 250 41 25th 6th 3000 36.0 200 125 2800 250 41 25th Comparative example 7 Middle class of the Ka beliso

Using the same vulcanizable polyethylene, an extruder of the same size and the same cable core as in Example 1, a vulcanized polyethylene insulated cable was produced using a conventional vertical steam vulcanizer at a speed of 0.28 m / min. The length of the Dampfvulkanisationskammer was 12 m, m is the length of the water cooling chamber. 11, the steam had a temperature of 205 ⁰ C and a pressure of 18 kg / cm ^2. The resulting cable had a No. 4 surface area. The number of voids in the insulating layer was determined by the method described in Example 1 (Note 3), and about 100 voids greater than 3/4 microns in diameter were found in one area of 170x 120 microns ^{2 found} in one from the be.

Comparative example 8

A vulcanized cable was produced in the manner described in Example 2 with the modification, that the molding aid (molding aid 1) not through a feed device for the molding aid but with the vulcanizable base material consisting of low-density polyethylene was mixed in an amount of 2.0 parts by weight per 100 parts by weight of the material. the However, extrusion of a vulcanized product was not possible because the material was on the inside The surface of the nozzle with a long flow path was severely vulcanized and stuck.

For this purpose 2 sheets of drawings

Claims (11)

Patent claims: 1. A method for deforming and vulcanizing a vulcanizable material, in which a Mixture of a polymer vulcanizable with the aid of organic peroxide and an organic one Peroxide is passed through a nozzle with a long flow path, which is a forming zone and an adjoining one Has vulcanization zone, while at the same time a molding aid on the inner surface of the Long flow path nozzle is fed in such a way that an uninterrupted film is between the inner surface of the nozzle and the polymer product is maintained, characterized in that that the molding aid used a) a viscosity of at least 1.1 centistokes and not more than 3000 centistokes at 235 ° C, b) has an absorption ratio in the polymer of less than 100 mg / cm ² at 150 ° C for 45 hours, c) does not gelatinize in contact with the organic peroxide during vulcanization will and d) does not boil during vulcanization. 2. The method according to claim 1, characterized in that one of the following as molding aid Connections is used: 1) Polyoxyalkylenes and their derivatives, random, block or graft copolymers of at least two alkylene oxides or their derivatives, with a molecular weight of more than 120 and less than 100,000, 2) polyhydric alcohols, including dehydration products of these compounds, with 4 to 50 carbon atoms and their alkyl esters or ethers, 3) Fatty acid alcohol amides with a total of more than 8 carbon atoms obtained from Fatty acids with 2 to 30 carbon atoms and alcohols with 1 to 30 carbon atoms, 4) fatty acid amides with 8 to 90 carbon atoms, 5) fatty acids with 8 to 30 carbon atoms and their metal salts, 6) Esters of polycarboxylic acids with 6 to 22 carbon atoms and monoalcohols with 1 up to 20 carbon atoms, 7) phosphoric acid esters of alkyl alcohols with 3 to 30 carbon atoms, 8) polyesters with a molecular weight of more than 200 and less than 30,000, 9) metal nitrates and metal halides, 10) Mixtures of polysiloxanes with a molecular weight of more than 2,000 and less than 100,000 and gelatinization inhibitors, 11) Mixtures of polysiloxanes with a molecular weight of more than 2,000 and less than 100,000 and an alkali metal hydroxide, alkali metal oxide, Alkaline earth metal hydroxide or alkaline earth metal oxide, and that the molding aid used as a continuous film between the inner surface of the The nozzle and the polymer product is arranged. 3. The method according to claims 1 or 2, characterized in that the deformed and vulcanized Polymeric polyethylene with a melt index of 0.1 to 2 is. 4. The method according to claims 1 to 3, characterized characterized in that for making an electrical Cable with a vulcanized coating a) a molten vulcanizable material consisting of a with the help of organic Peroxide vulcanizable polymers and an organic peroxide, continuously on one electrical conductor is extruded, b) the material is deformed and vulcanized by placing it at elevated temperature and elevated temperature Pressure is passed through a nozzle with a long flow path, which has a molding zone and a subsequent vulcanization zone, while at the same time applying a molding tool to the inner surface of the nozzle with long Flow path is applied, which 1) a viscosity of at least 1.1 centistokes and at most 3000 centistokes 235 ° C, 2) has an absorption ratio in the polymer of less than 30 mg / cm ² for 45 hours at 150 ^° C, 3) not gelatinized in contact with the organic peroxide during vulcanization will and 4) does not boil during vulcanization,
and c) the coated conductor, after exiting the end of the nozzle with a long flow path, is cooled ^{with the aid of cooling water under pressure of 15 to 30 kg / cm 2.} 5. The method according to claim 4, characterized in that the polymer used is polyethylene with a melt index of 0.1 to 2.0, the vulcanization zone of the nozzle with a long flow path is kept at a temperature between 200 ⁰ C and 300 ⁰ C and that the molding aid is selected from the following compounds: polyoxyalkylenes and their derivatives, random, block or graft copolymers of at least 2 alkylene oxides and their derivatives, the molecular weight of which is more than 120 and less than 100,000, or a mixture of these materials.