Composition for cable sheath

 

(57) Abstract:

Describes a composition for cable sheath consisting of a multimodal mixture of olefinic polymers and representing multimodal mixture of olefinic polymers, telenovelas or propyleneglycol obtained by polymerization of at least one-olefin in more than one stage and having a density of about 0,915-0,955 g/cm3and the rate of melt flow of about 0.1 to 3.0 g/10 min, and the mixture of olefinic polymers contains at least first and second olefin polymers, the first of which has the density and velocity of the melt is selected from (a) about 0,930 is 0.975 g/cm3and about 50-2000 g/10 min and (b) approximately 0.88-0,93 g/cm3and about 0.1-0.8 g/10 min Technical result is a composition with a given density and velocity of the melt. 3 S. and 9 C.p. f-crystals, 3 tables.

The present invention relates to compositions for cable sheath, and also to its use as the outer sheath power cable or a communication cable.

The cables, which means power cables high voltage, medium voltage or low voltage and communication cables, such as optical cables, knogo or more layers. The outer layer is called the outer sheath or shielding layer, and in our time it is made from a polymeric material, preferably of polyacyladipate. A very wide range of applications different types of cables, such as telecommunications cables, including conventional copper cables and fiber optic cables, and power cables, make up for the fact that the sheath material must meet several requirements on properties that are in some ways contradictory. Thus, an important material properties for the shell of the cable are good machinability, i.e., the material should be easily handled in a wide temperature range; low shrinkage; high mechanical strength; good processing quality coating, and high resistance to cracking under stress environment (STNAS). Because before that it was difficult or even impossible to satisfy all these requirements on the properties, prototype materials shell were the result of a compromise that good properties in one respect was achieved through the worst properties in some other respect. The closest solution essence and the achieved technical resulatem molecular weight and ethylene polymers with a low molecular weight, used for the cable jacket.

However, the specified polymer mixtures inherent in the above-described disadvantages.

The basis of the invention is the composition for the shell of the cable, which would be advantageously reduced or even eliminated compromise regarding material properties for the shell of the cable, namely improve STNAS material and reduce its shrinkage at a given workability.

The problem is solved in that the composition for cable sheath consisting of a multimodal mixture of olefinic polymers according to the invention is a multimodal mixture of olefin polymers telenovelas or propyleneglycol obtained by polymerization of at least one-olefin in more than one stage and having a density of about 0,915-0,955 g/cm3and the rate of melt flow of about 0.1 to 3.0 g/10 min, and the mixture of olefinic polymers contains at least first and second olefin polymers, the first of which has the density and velocity of the melt is selected from (a) about 0,930 is 0.975 g/cm3and about 50-2000 g/10 min and (b) approximately 0.88-0,93 g/cm3and about 0.01 to 0.8 g/10 min.

The composition of the shell Kabel for cable sheath, consists of a multimodal mixture of olefin polymers having certain specified values of the density and velocity of the melt with respect to polymer blends, and polymer, forming a part thereof, has improved properties. In addition, the invention relates to the use of this composition for cable sheath outer sheath power cable or a communication cable.

However, before the invention will be described in more detail, will identify some of the key expressions. Under the "modality" of a polymer refers to the structure of the molecular mass distribution of the polymer, i.e. the appearance of the curve indicating the number of molecules as a function of molecular weight. If the curve has a maximum, say that the polymer is a "unimodal", while in the case of a curve with a very wide maximum or with two or more peaks, and when the polymer consists of two or more fractions, say that the polymer is "bimodal", "multimodal" and so on In subsequent all the polymers, for which the curve of the molecular mass distribution is very wide, or has more than one maximum, together referred to as "multimodal".

The term " / min net which has been created the term "melt index". The flow rate of the melt is indicated in g/10 min, shows fluidity, and therefore, the workability of the polymer. The higher the flow velocity of the melt, the lower the viscosity of the polymer.

The term "resistance to cracking under stress environment" (STNAS) implies stability of the polymer to the formation of cracks under the influence of mechanical stress and the reagent in the form of surfactants. STNAS determined in accordance with ASTM D 1693 And, with the used reagent is Igepal CO-630.

The term "polietylenowych" refers to plastic-based polyethylene or copolymers of ethylene and a monomer ethylene is the bulk.

As stated previously, the composition for cable sheath in accordance with the invention is characterized in that it consists of a multimodal mixture of olefinic polymers with a given density and velocity of the melt.

It was previously known about receiving multimodal, in particular bimodal olefin polymers, preferably multimodal polyethyleneglycol in two or more reactors connected in series. As examples of the prior art may be mentioned the EP IN accordance with the data links each of the stages of the polymerization can be performed in the liquid phase, in suspension or in the gas phase.

In accordance with the present invention the main stage polymerization is preferably carried out in combination, a suspension polymerization/gas-phase polymerization or gas-phase polymerization/gas-phase polymerization. Suspension polymerization is preferably carried out in the so-called reactor with circulation. The use of suspension polymerization in the reactor mixture is not preferred in the present invention, since such a method is not flexible enough to obtain compositions according to the invention and has problems with solubility. In order to obtain the composition according to the invention, with improved properties, require a flexible method. For this reason, it is preferable that the composition was obtained in two main stages of polymerization in combination reactor circulation/gas-phase reactor or a gas-phase reactor/gas-phase reactor. Particularly preferably, the composition received on the two main stages of the polymerization, when the first stage is carried out in the form of suspension polymerization in the reactor circulation, and the second stage is carried out in the form of a gas-phase polymerization in the gas-phase reactor. The basis of the EU.%, preferably 1-10 wt.% of the total number of polymers. Typically, this technique leads to a multimodal mixture of polymers by polymerization with chromium, metallocene or catalyst of Ziegler-Coloring in several sequential polymerization reactors. When receiving, for example, bimodal polyacyladipate, which is in accordance with the invention is a preferred polymer, the first ethylene polymer is produced in the first reactor under certain conditions in respect of the Monomeric composition, the pressure of the hydrogen gas, temperature, pressure, etc. After polymerization in the first reactor, the reaction mixture containing the obtained polymer, served in the second reactor, where a further polymerization under other conditions. Usually in the first reactor to obtain a first polymer with high melt flow (low molecular weight) with moderate or small addition of co monomer or without this addition, while in the second reactor to receive the second polymer with a low rate of flow of the melt (high molecular weight) with a larger addition of co monomer. As co monomer in copolymerization of ethylene usually use other olefins, Iman, hexene, octene, daken and so on, the final product consists of a homogeneous mixture of the polymers of the two reactors, and the various curves of the molecular-mass distribution for these polymers together form the curve of molecular weight distribution, having a high maximum or two maxima, i.e. the end product is a bimodal polimeros mixture. As multimodal and especially bimodal polymers, preferably ethylene polymers, and methods for their production are owned by the state of the art, they are not involved in the detailed description, however, reference is made to the above description.

Here you must specify that upon the receipt of two or more polymer components in the corresponding number of reactors connected in series, the flow velocity of the melt, density and other properties can be measured directly extracted material only if the component obtained in the first stage reactor, and in the case of the final product. The relevant properties of the polymer component obtained in the stages in the reactor after the first stage, can only be determined indirectly on the basis of relevant quantities of materials added and VIV getting known in themselves, it is unknown what previously such multimodal polymer mixture used in the compositions of the cable jacket. In addition, previously was not aware of any use in this context, multimodal polymer mixtures having special values of density and velocity of the melt, which are required in the present invention.

As mentioned above, preferably, the multimodal blend of olefin polymers in compositions for cable sheath in accordance with the present invention was bimodal polymer mixture. Also preferably, this bimodal polymer blend was obtained by polymerization as described above, under different conditions of polymerization in two or more polymerization reactors connected in series. Thanks achieved thus flexibility in regard to the reaction conditions most preferably, the polymerization was performed in the reactor with circulation/gas-phase reactor, gas-phase reactor/gas-phase reactor or in a reactor with a circulation reactor with circulation as the polymerization of one, two or more olefin monomers, and various stages of polymerization would have a variable content of co monomer. Preferably, the preferably in the first stage, is formed of a relatively low molecular weight polymer having moderate, low or preferably zero the contents of the co monomer, due to the high content of the carrier kinetic chain (gaseous hydrogen); and on the other, preferably in the second stage, the obtained high-molecular polymer having a higher content of co monomer. However, the order of these stages may be reversed.

Preferably, the multimodal blend of olefin polymers in accordance with the invention was a mixture of polypropyleneglycol or most preferably of polyethyleneglycol. Comonomer or comonomers in the present invention are selected from the group consisting of a-olefins having up to 12 carbon atoms; in the case of polyacyladipate this means that comonomer or comonomers selected from among-olefins having 3-12 carbon atoms. Particularly preferred comonomers are butene, 4-methyl-1-penten, 1-hexene and 1-octene.

In view of the foregoing, the preferred mixture of polyethyleneglycol in accordance with the invention consists of low molecular weight homopolymer ethylene mixed with high molecular weight copolymer of ethylene and butene, 4-methyl - 1-pentene, 1-hexene or 1-OCTT selected to the final mixture of olefinic polymer had a density of about 0.915-0.955 g/CC, preferably about 0.920-0.950 g/CC, and the rate of melt flow of about 0.1-3.0 g/10 min, preferably about 0.2-2.0 g/10 min In accordance with the invention is preferably achieved using a mixture of olefinic polymers containing the first olefin polymer having a density of about 0.930-0.975 g/CC, preferably about 0.955-0.975 g/CC, and the rate of melt flow of about 50-2000 g/10 min, preferably about 100 to 1000 g/10 min and most preferably about 200-600 g/10 min; and at least a second olefin polymer having a density and a flow velocity of the melt, the mixture of olefinic polymers acquires the density and velocity of the melt above.

If multimodal mixture of olefinic polymer is bimodal, i.e. a mixture of two olefinic polymers (the first olefinic polymer and a second olefin polymer), and the first olefin polymer is produced in the first reactor and it is above the density and velocity of the melt flow, the density and the flow velocity of the melt of the second olefinic polymer, which is obtained in the second stage reactor, as ukazanii in the reactor.

When the mixture of olefinic polymers and the first olefin polymer have the above values of the density and velocity of the melt flow, the calculation shows that the second olefinic polymer obtained in the second stage, should have a density of approximately 0.88-0.93 g/CC, preferably 0.91-0.93 g/CC, and the rate of melt flow of approximately 0.01-0.8 g/10 min, preferably about 0.05-0.3 g/10 min.

As indicated earlier, the order of the stages may be reversed; this means that if the final mixture of the olefin polymer has a density of about 0.915-0.955 g/CC, preferably about 0.920-0.950 g/CC, and the rate of melt flow of about 0.1-3.0 g/10 min, preferably about 0.2-2.0 g/10 min, and the first olefin polymer obtained in the first stage, has a density of about 0.88 - 0.93 g/CC, preferably about 0.91-0.93 g/CC, and the rate of flow of the melt 0.01-0.8 g/10 min, preferably about 0.05-0.3 g/10 min, according to the above calculations, the second olefinic polymer obtained in the second stage of the two-stage method has a density of approximately 0.93-0.975 g/CC, preferably about 0.955-0.975 g/CC, and the speed of the melt 50-2000 g/10 min, preferably about 100 to 1000 g/10 min and most preferably about 200 to 600 g/1 is m invention is less preferred.

In order to optimize the properties of the composition for a cable sheath in accordance with the invention, the individual polymers should be present in the mixture of olefin polymers in such a weight ratio to the required properties, which contribute to the individual polymers were also achieved in a finite mixture of olefinic polymers. In the individual polymers must not be present in such small amounts, for example about 10 wt.% or less, in which they do not affect the properties of the mixture of olefinic polymers. More specifically, it is preferable that the amount of olefin polymer having a high flow velocity of the melt (low molecular weight), was at least 25 wt.%, but not more than 75 wt.% of the total polymer, preferably 35-55 wt.% of the total polymer to thus optimize the properties of the final product.

The use of multimodal mixtures of olefin polymers of the above type leads to compositions for cable sheath according to the invention, which have much better properties than conventional compositions for cable sheathing, especially in regard to shrinkage, STNAS and machinability. In particular, the big advantage of the Yayoi, composition for cable sheath in accordance with the invention can be used for outer covers of the cables, including power cables and communication cables. From the number of power cables, the outer shell which can be an advantage obtained from the composition for cable sheath according to the invention, mention can be made of the high-voltage cables, medium voltage cables and of nizkovolnye cables. From the number of communication cables, external shell which can be with advantage made of compositions for cable sheath according to the invention, mention can be made of cables, paired cables, coaxial cables and optical cables.

Here are some non-limiting examples are intended to further clarify the invention and its advantages.

Example 1

In the polymerization, consisting of a reactor with circulation, connected in series with the gas-phase reactor, and comprising a catalyst of the Ziegler-Coloring, polymerizable bimodal polietylenowych under the following conditions.

The first reactor (reactor circulation)

In this first reactor polymer (polymer 1) was obtained by polymerization of ethylene in the presence of water the density of 0.975 g/cubic cm

The second reactor (gas-phase reactor)

In this reactor, the second polymer (polymer 2) was obtained by polymerization of ethylene and butene (molar ratio of ethylene to butene in the gas phase 0.22:1, hydrogen to ethylene 0.03:1). The resulting copolymer of ethylene and butene are present in the form of a homogeneous mixture with homopolymer ethylene from the first reactor, and the weight ratio of polymer 1 polymer 2 was 45:55.

Bimodal mixture of polymer 1 and polymer 2 had a density of 0.941 g/CC, and a P value of 0.4 g/10 min. After mixing with soot obtained a final product containing 2.5 weight. % black carbon, which led to a final density of 0.951 g/cubic cm In the future, this final product will be called bimodal polyethyleneglycol 1.

Bimodal polietylenowych 1 was used as the compound for cable sheath, and the properties of this composition were determined and compared with the properties of conventional compositions for cable sheath from the unimodal polyacyladipate (reference 1). Standard 1 had a density of 0.941 g/CC (after mixing up soot 2.5 wt.% the density of 0.951 g/CC) and the P value 0.24 g/10 min.

In this example, as well as in the following examples, the shrinkage of the obtained compositions was determined in accordance with the s for shells to shrinkage. Shrinkage is determined as follows.

The cable samples to assess ekstragiruyut as follows.

Conductor: - 3.0 mm solid A1 Explorer

Wall thickness: mm - 1.0 mm

The temperature of the head: - +210oC or +180oC

The distance between the head and water bath: - 35 cm

The temperature of the water bath at +23oC

The linear speed of 75 m/min

Head type - Polustrovo

Nozzle - 3.65 mm

Head - 5.9 mm

Design of screw - Elise

Distributive lattice

Shrinkage in percent measured after 24 hours in a room with constant temperature (+23oC) and after 24 hours at a temperature of +100oC.

Measure the cables of approximately 40 cm is Convenient to sample the cable was marked so that the measurement after kondicionirovanie could be performed on the same point of the sample cable.

If you find that the sample usedat during measurement, you must first make a mark at about 40 see then cut along the length and a second dimension. From each of the analyzed cable select double samples. The sample is placed in a room with constant temperature for 24 hours, then measure and calculate the magnitude ubrcy measure and calculate the total shrinkage in percent based on the original length. The measurement results are listed in table 1 (see end of description).

From the following table 1 values it is obvious that the material for the shell according to the invention exhibits improved properties in respect of shrinkage, especially at room temperature, and resistance to cracking under stress environment (STNAS). Mechanical tensile properties of the material for the shell in accordance with the present invention are at the level of properties of the standard 1. In addition, the machinability of the material for the shell in accordance with the invention, which can be judged by the value of P, is as good as machinability for reference 1. It should be emphasized that while the material for the shell of the standard 1 has good properties of workability to be achieved at the expense of the poor shrinkage properties, especially at room temperature, the material for the shell in accordance with the invention has good properties machinability, and good (low) shrink properties. This is a significant advantage, which increases improved properties on STNAS material for the shell in accordance with the invention.

Example 2

Installation for p is ctor (reactor circulation)

In this first reactor polymer (polymer 1) was obtained by polymerization of ethylene in the presence of hydrogen (molar ratio of hydrogen to ethylene 0.38 : 1). The obtained homopolymer of ethylene mattered PAGE 444 g/10 min and a density of 0.975 g/cubic cm

The second reactor (gas-phase reactor)

In this reactor, the second polymer (polymer 2) was obtained by polymerization of ethylene and butene (molar ratio of butene to ethylene 0.23:1, the molar ratio of hydrogen to ethylene 0.09 : 1). The resulting copolymer of ethylene and butene are present in the form of a homogeneous mixture with homopolymer ethylene from the first reactor, and the weight ratio of polymer 1 polymer 2 was 40:60.

Bimodal mixture of polymer 1 and polymer 2, which formed the final product had a density of 0.941 g/CC (after adding 2.5 wt.% soot 0,951 g/CC) and a P value of 1.4 g/10 minutes In the future, this final product will be called bimodal polyethyleneglycol 2. A similar image was obtained another bimodal polietylenowych (hereinafter called bimodal polyethyleneglycol 3), the molar ratio of hydrogen to ethylene in the first reactor was 0.39:1, and the obtained homopolymer of ethylene (polymer 1) in the first reactor had in the 2), moreover, the molar ratio of butene to ethylene was 0.24:1 and the molar ratio of hydrogen to ethylene was 0.07:1. The weight ratio of polymer 1 polymer 2 was 45:55. The final product (bimodal polietylenowych 4) had a density of 0.941 g/CC (after mixing with 2.5 weight. % soot 0,951 g/CC) and a P value of 1.3 g/10 min.

Bimodal polietylenowych 2 and bimodal polietylenowych 3 was used as a compound for cable sheath, and the properties of these compositions were determined and compared with the properties of the prototype composition for the shell (reference 2). Standard 2 was a special composition intended for use in those cases when it is required particularly low shrinkage, for example in fiber optic applications, and this composition consisted of a mixture of melt fractions of polyethylene, having a density of 0.960 g/CC, and the value of P 3.0 g/10 min, and another fraction of polyethylene, having a density of 0.920 g/CC, and a P value of 1.0 g/10 minutes, This resulted in an end product having a density of 0.943 g/CC (after adding 2.5 wt.% soot 0,953 g/CC) and a P value of 1.7 g/10 min.

The results of measurements of the properties of the three songs for the shell shown in table 2 (see end of description).

Kista at room temperature. However, the shrinking properties of the standard 2 is achieved at the expense of the poor properties of workability, which, among other things, to the value of the quality of surface treatment. Typically, the material for the shell pattern 2 can be processed only within a narrow "window treatments", i.e. in the narrow limits of processing parameters. Unlike standard 2 materials for the shell in accordance with the invention (bimodal polietilenplastika 2 and 3) show the same good shrink properties as the standard 2, representing the best properties machinability (wider processing window), including the best surface quality of the cable sheath. In addition, the materials for the shell in accordance with the invention exhibit a better resistance to cracking under stress environment (STNAS) and provide good tensile strength.

Example 3

The apparatus for polymerization used in examples 1 and 2, received bimodal polietylenowych (polietylenowych 4) under the following conditions.

The first reactor (reactor circulation)

In this first reactor polymer (polymer 1) was obtained by polymerization of ethylene in the presence of 1-bout the giving PAGE 310 g/10 min and a density of 0.939 g/cubic cm

The second reactor (gas-phase reactor)

The polymer from the reactor with circulation moved in gas-phase reactor, where they spent an additional polymerization of ethylene with 1-butene in the presence of gaseous hydrogen (molar ratio of 1-butene:gaseous hydrogen:ethylene 0.80:0.02:1), which led to a new polymer component (polymer 2). The weight ratio of polymer 1 polymer 2 was 42:58. The value of P obtained product was 0.3 g/10 min, and the density was equal to 0.922 g/cubic cm

In this case, when both the polymer component contained 1-butene as co monomer, also achieved excellent mechanical properties, good STNAS and good shrinkage properties, as is clear from table 3 (see the end of the description).

1. Composition for cable sheath consisting of a multimodal mixture of olefinic polymers, characterized in that it is a multimodal mixture of olefin polymers telenovelas or propyleneglycol obtained by polymerization of at least one-olefin in more than one stage and having a density of about 0,915 - 0,955 g/cm3and the rate of melt flow of about 0.1 to 3.0 g/10 min, and the mixture of olefin polymers sodergreen, selected from (a) about 0,930 is 0.975 g/cm3and about 50 to 2000 g/10 min and (b) approximately 0.88 - 0,93 g/cm3and about 0.01 to 0.8 g/10 min.

2. The composition according to p. 1, wherein the first olefin polymer has a density of about 0,930 is 0.975 g/cm3and the rate of melt flow of about 50 to 2000 g/10 min.

3. Composition under item 1 or 2, characterized in that the mixture of the olefin polymer has a density of about 0,920 - 0,950 g/cm3and the rate of melt flow of about 0.2 - 2.0 g/10 min and that of the first olefin polymer has a density of about 0,955 - 0, 975 g/cm3and the rate of melt flow of about 100 to 1,000 g/10 min.

4. Composition according to any one of paragraphs.1 to 3, characterized in that the mixture of olefin polymers is a mixture of polyethyleneglycol.

5. Composition according to any one of paragraphs.1 to 4, characterized in that it is obtained by coordinating and catalytic polymerization of ethylene in at least two stages and a-olefin co monomer having 3 to 12 carbon atoms, at least one stage.

6. The composition according to p. 5, characterized in that stage polymerization is carried out in the form of a slurry polymerization, gas phase polymerization or combinations thereof.

7. The composition according to p. 6, characterized in that it is connected with the fact, the process is carried out in a circulation reactor/gas-phase reactor, where at least one circulation of the reactor should be at least one gas-phase reactor.

9. Composition according to any one of the preceding paragraphs, characterized in that it is a bimodal mixture of polyethyleneglycol.

10. The composition according to p. 9, characterized in that the first polietylenowych up to 25 to 75 wt.% of the total number of polymers in the composition.

11. Composition for cable sheath, characterized in that it is a composition according to any one of the preceding paragraphs.1 to 10 and is used as the outer sheath of the power cable.

12. Composition for cable sheath, characterized in that it is a composition according to any one of the preceding paragraphs.1 to 10 and is used as the outer sheath of communication cable.

 

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