KR20240050687A - Insulation composition comprising a thermoplastic polymer - Google Patents

Abstract

The present invention relates to an insulating composition that can be used for various power components, and more specifically, to provide an insulating composition in which a very small amount of thermoplastic polymer is mixed with a polymer substrate to improve the insulating properties of insulators used in power components. It is characterized by

Description

Insulating composition comprising a thermoplastic polymer {INSULATION COMPOSITION COMPRISING A THERMOPLASTIC POLYMER}

The present invention relates to an insulating composition comprising a thermoplastic polymer.

Polymer materials, known as electrically insulating materials, have been widely used in a variety of high voltage (HV) insulation applications. For example, cross-linked polyethylene (PE) or polypropylene (PP) is mainly used as an insulating material for high-voltage power cables due to its mechanical compatibility and ease of processing. However, these polymers are composed of a complex structure including crystalline and amorphous regions and their interface regions, so they are vulnerable to charges injected under high electric fields. When charge carriers are injected into a polymer under high voltage, the injected charge carriers easily accumulate in the amorphous or interface region where the molecules are loosely arranged, causing partial destruction and reducing the insulation lifespan.

A common method to improve the electrical properties of polymers with unfavorable chemical structures is to introduce inorganic nanoparticles into the polymers. Studies have been reporting for a long time that the volume resistance or breakdown strength of polymers can be improved when small amounts of metal oxide-based inorganic nanoparticles are incorporated. Since inorganic nanoparticles are difficult to disperse within the polymer, organic substances are used to improve the surface. It is an essential method to improve affinity with polymers and improve dispersibility through processing.

A technology for a polymer-based insulating composition incorporating surface-treated inorganic nanoparticles, "a method for producing an organic-inorganic nanocomposite using inorganic nanoparticles surface-treated with hydroxy acid and a thermoplastic polymer, and an organic-inorganic nanocomposite manufactured therefrom" "Composite (KR 10-2021-0054135 A)" discloses a method of treating the surface of magnesium oxide nanoparticles with hydroxy acid and dispersing it in a thermoplastic polymer substrate, thereby obtaining the effect of increasing insulation breakdown strength. In "DC power cable with space charge reduction effect (KR 10-1161360 B1)", the surface of magnesium oxide nanoparticles is treated with vinyl silane to improve dispersibility, thereby increasing volume resistance and dielectric breakdown strength. Rather, it discloses suppressing space charge accumulation. In "Epoxy-silica nanohybrid resin with improved insulating properties, resin manufacturing method, and voltage stabilizer for epoxy resin (KR 10-2018-0047440 A)", the surface of silica nanoparticles is treated with alkoxy silane, dispersed in an epoxy substrate, and then It is disclosed that the insulation breakdown voltage increases. In "Insulating materials containing nanosilica and cross-linked polyethylene and cables using the same (KR 10-2019-0125731 A)", the surface of silica nanoparticles is treated with fatty acid, vinyl silane, or polymer resin to improve dispersibility in polyethylene. and a cable incorporating this is disclosed.

In addition to using the inorganic nanoparticles, organic single molecules based on aromatic compounds are used as voltage stabilizers. “Voltage-stabilized polymer composition (KR 10-2236518 B1)” uses organic carboxylic esters containing at least one aromatic ring and 1 to 2 carboxyl alkyl ester substituents as voltage stabilizers to improve the alternating current breakdown strength of polyethylene. Start improving. "Energy Cable with Voltage Stabilized Thermoplastic Electrical Insulating Layer (KR 10-2017-0139696 A)" proposes to improve insulation breakdown strength by using benzophenone-based organic material as a voltage stabilizer.

However, the surface treatment process for dispersing inorganic nanoparticles is mainly carried out using solvents, which not only poses environmental problems, but also has disadvantages due to the high price of surface treatment agents and complicated processes. Voltage stabilizers based on organic single molecules are There is a possibility that it may elute even after being mixed into the polymer, and there is a problem with long-term stability, making it difficult to solve the instability of the insulating composition.

KR 10-2021-0054135 A KR 10-1161360 B1 KR 10-2018-0047440 A KR 10-2019-0125731 A KR 10-2236518 B1 KR 10-2017-0139696 A

The present invention was invented to solve the above problems, and its technical problem is to provide an insulating composition containing a thermoplastic polymer to improve insulating properties.

In order to solve the above technical problems, the present invention provides an insulating composition containing a thermoplastic polymer, which has insulating properties by mixing 0.001 to 1.0 phr of a thermoplastic polymer with respect to 100 phr of a polymer substrate.

In the present invention, the thermoplastic polymer is polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyphenyline sulfide, polyacetal, polyvinyl acetate, polyacrylate, fluorine resin, poly It is characterized in that it is at least one selected from the group consisting of vinylidene fluoride, polyvinyl chloride, acrylonitrile-butadiene-styrene rubber, ethylene-based elastomer, and ethylene-propylene rubber.

In the present invention, the polymer substrate is characterized in that it is at least one selected from the group consisting of thermoplastic polymer resin and thermosetting polymer resin.

In the present invention, the thermoplastic polymer resin includes polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyphenyline sulfide, polyacetal, polyvinyl acetate, polyacrylate, fluorine-based resin, It is characterized in that it is at least one selected from the group consisting of polyvinylidene fluoride, polyvinyl chloride, acrylonitrile-butadiene-styrene rubber, ethylene-based elastomer, and ethylene-propylene rubber.

In the present invention, the thermosetting polymer resin is one selected from the group consisting of epoxy resin, phenol resin, melamine resin, phenol resin, furan resin, urea resin, unsaturated ester resin, alkyd resin, polyurethane resin, and silicone rubber resin. It is characterized by being more than one species.

In the present invention, the heat distortion temperature of the thermoplastic polymer is characterized as a temperature below the melting point of the polymer substrate.

In the present invention, the thermoplastic polymer has a diameter of 1 to 100 nm and is dispersed in the polymer substrate.

According to the insulating composition containing the thermoplastic polymer of the present invention as a means of solving the above problem, the insulating properties of the polymer substrate can be improved only by mixing a very small amount of the thermoplastic polymer.

That is, when a thermoplastic polymer, which is an additive, is mixed with a polymer base, the thermoplastic polymer is doped with the polymer base, thereby improving the distribution of small-sized crystals in the polymer base and thereby effectively improving the insulation properties, and thus, conventionally used It has the effect of replacing voltage stabilizers based on inorganic nanoparticles or organic single molecules.

Figure 1(a) is a polarizing microscope image of an insulating composition mixed with a polystyrene-based thermoplastic polymer according to Example 1, and Figure 1(b) is a scanning electron microscope image.

Since the present invention can be subject to various changes and can have various forms, embodiments will be described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Throughout the specification, when a part is said to “include” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as having an ideal or excessively formal meaning unless clearly defined in this specification. .

The terms used herein are merely used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

The present invention relates to an insulating composition comprising a thermoplastic polymer for use in high voltage electrical components. That is, the present invention melts and mixes a very small amount of thermoplastic polymer as an additive in the polymer substrate constituting the polymer insulator for high-voltage electrical components, thereby increasing the breakdown strength and volume resistance of the polymer insulator composition due to the presence of thermoplastic polymer dispersed in small sizes. and suppresses the accumulation of space charges or increases the tree start voltage.

The insulating composition according to the present invention is characterized by having insulating properties by mixing 0.001 to 1.0 phr of thermoplastic polymer as an additive with 100 phr of the polymer base.

The polymer substrate constitutes the base resin of the insulating composition. Such a polymer substrate can be used by selecting one or more types from the group consisting of thermoplastic polymer resin and thermosetting polymer resin.

Thermoplastic polymer resins include polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyphenyline sulfide, polyacetal, polyvinyl acetate, polyacrylate, fluorine-based resin, polyvinylidene fluoride, It may be one or more selected from the group consisting of polyvinyl chloride, acrylonitrile-butadiene-styrene rubber, ethylene-based elastomer, and ethylene-propylene rubber. Among them, isotactic polypropylene can be used as polypropylene, and it is not limited to the above-mentioned types of thermoplastic polymer resins, and various thermoplastic polymer resins can be used.

In the case of thermosetting polymer resin, it may be one or more selected from the group consisting of epoxy resin, phenol resin, melamine resin, phenol resin, furan resin, urea resin, unsaturated ester resin, alkyd resin, polyurethane resin, and silicone rubber resin, and may be thermoplastic. As with polymer resins, it is not limited to the above types and various thermosetting polymer resins can be used.

The thermoplastic polymer is dispersed by melting and mixing it with an additive in a polymer substrate. Thermoplastic polymers that are melt-mixed and dispersed in polymer substrates include polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyphenyline sulfide, polyacetal, polyvinyl acetate, polyacrylate, and fluorine-based resin. , polyvinylidene fluoride, polyvinyl chloride, acrylonitrile-butadiene-styrene rubber, ethylene-based elastomer, and ethylene-propylene rubber.

Among the thermoplastic polymers, polystyrene has the structure shown in Chemical Formula 1 below, and the benzene group of polystyrene acts as a voltage stabilizer to improve the electrical properties of the insulating composition.

[Formula 1]

The heat distortion temperature of such a thermoplastic polymer is preferably a temperature below the melting point of the polymer substrate. For example, the heat distortion temperature of polystyrene, which is a thermoplastic polymer as an additive, is about 100 ℃, and the melting point of isotactic polypropylene, which is a polymer substrate, can be 160 to 165 ℃, which occurs during the process of melting and mixing the thermoplastic polymer as an additive with the polymer substrate. This is to allow the thermoplastic polymer added in very small amounts to act as a crystal nucleus and rearrange the crystals of the isotactic polypropylene resin so that the polymer substrate can grow uniformly from the crystal nucleus.

In the case of thermoplastic polymers dispersed in a polymer substrate, the diameter may be 1 to 100 nm. If the thermoplastic polymer is dispersed in a polymer substrate with a diameter of less than 1 nm, it is not helpful in improving the insulating properties due to its too small size. If the thermoplastic polymer is dispersed in a polymer substrate with a diameter exceeding 100 nm, it is difficult to serve as a crystal nucleus and also contains impurities. It has the disadvantage of deteriorating the insulation properties.

In particular, it is preferable that the thermoplastic polymer, which is an additive, is melt-mixed and dispersed within the polymer substrate in the range of 0.001 to 1.0 phr with respect to 100 phr of the polymer substrate. If the thermoplastic polymer as an additive is melt-mixed at less than 0.001 phr with respect to 100 phr of the polymer base, the thermoplastic polymer as an additive cannot serve as a crystal nucleus and ultimately cannot improve the electrical properties of the insulating composition. If it is melt-mixed in excess of 1.0 phr, It is undesirable because it aggregates with each other and exists as a large-sized dispersed phase, which may cause deterioration of the insulating properties.

The above insulating composition has the advantage of relatively increasing the breakdown strength and volume resistance of a single polymer substrate by dispersing the thermoplastic polymer into the polymer substrate through a melt mixing method as an additive, and is therefore widely used for high-voltage electrical components. possible.

Hereinafter, embodiments of the present invention will be described in more detail as follows. However, the following examples are merely illustrative to aid understanding of the present invention and are not intended to limit the scope of the present invention.

<Example 1>

Prepare a batch melt mixer (Brabender), add 0.001 phr of polystyrene, a thermoplastic polymer, to 100 phr of isotactic polypropylene resin, which is a polymer base, into the batch melt mixer, and then melt and mix at 200°C for 20 minutes to obtain thermoplasticity. An insulating composition containing a mixture of polymers was prepared.

<Example 2>

Prepare a batch melt mixer (Brabender), add 0.01 phr of polyvinylidene fluoride, a thermoplastic polymer, to 100 phr of isotactic polypropylene resin, which is a polymer base, into the batch melt mixer, and then mix at 200°C for 20 minutes. An insulating composition containing thermoplastic polymers was prepared by melt mixing.

<Example 3>

Prepare a batch melt mixer (Brabender), add 0.001 phr of polymethyl methacrylate, a thermoplastic polymer, to 100 phr of isotactic polypropylene resin, which is a polymer base, into the batch melt mixer, and then mix at 200°C for 20 minutes. An insulating composition containing thermoplastic polymers was prepared by melt mixing.

<Example 4>

Prepare a batch melt mixer (Brabender), add 1.0 phr of low-density polyethylene, a thermoplastic polymer, to 100 phr of isotactic polypropylene resin, which is a polymer base, into the batch melt mixer, and then melt and mix at 200°C for 20 minutes. An insulating composition containing a mixture of thermoplastic polymers was prepared.

<Example 5>

Prepare a batch melt mixer (Brabender), add 0.01 phr of impact-resistant polystyrene, a thermoplastic polymer, to 100 phr of isotactic polypropylene resin, which is a polymer base, into the batch melt mixer, and then melt and mix at 200°C for 20 minutes. An insulating composition containing a mixture of thermoplastic polymers was prepared.

<Comparative Example 1>

Unlike Examples 1 to 5, only pure polypropylene was used as the insulating composition.

In Examples 1 to 5 and Comparative Example 1, the content of the thermoplastic polymer added per 100 phr of the polymer-based isotactic polypropylene resin is summarized in Table 1 below. At this time, phr, the unit of content of the thermoplastic polymer, is part per hundred resin, which corresponds to the weight part of the thermoplastic polymer, which is an additive added per 100 parts by weight of the polymer base.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 polystyrene 0.001 - - - - - polyvinylidene fluoride - 0.01 - - - - polymethyl methacrylate - - 0.001 - - - low density polyethylene - - - 1.0 - - Impact resistant polystyrene - - - - 0.01 -

Meanwhile, Figure 1(a) is a polarizing microscope image of an insulating composition mixed with a polystyrene-based thermoplastic polymer according to Example 1, and Figure 1(b) is a scanning electron microscope image. Referring to Figures 1(a) and 1(b), it can be seen that polystyrene is mixed with isotactic polypropylene resin, which is a polymer base. Isotactic polypropylene resin, which is a polymer base, has crystallinity. In the process of melting and mixing the thermoplastic polymer, which is an additive, with the polymer base, a very small amount of thermoplastic polymer is added as a crystal nucleus, and the crystals of the isotactic polypropylene resin are regenerated. As the polymer substrate grows uniformly from the crystal nuclei while being arranged, the insulating properties of the insulating composition can be improved.

<Test Example 1>

In this test example, the physical properties of the insulating compositions according to Examples 1 to 5 and Comparative Example 1 were analyzed. In relation to this, the insulating compositions of Examples 1 to 5 and Comparative Example 1 were molded at 200°C at a pressure of 10 MPa using a hot press molding machine, and then rapidly cooled at a temperature of 10°C to form a film with a thickness of 150 ㎛. Samples were manufactured, and the volume resistance and breakdown strength of the film samples were tested in accordance with IEC 60243, and the values were measured at room temperature and 110 ° C, respectively, and are shown in Table 2 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Volume resistance (room temperature)
(Ω·cm) 1.47E18 1.56E18 3.17E18 8.38E17 2.38E18 1.09E18 Volume resistance (110 ℃)
(Ω·cm) 8.32E16 3.85E16 3.12E16 7.12E15 7.92E16 5.39E16 Direct current insulation breakdown strength (room temperature)
(kV/mm) 449.7 462.0 443.8 388.2 518.6 312.0 Direct current breakdown strength (110 ℃)
(kV/mm) 248.3 203.7 227.5 168.3 304.4 185.9

Referring to Table 2, compared to Comparative Example 1 using only pure polypropylene as the insulating composition, the relative volume resistance (room temperature/110 ℃) and direct current breakdown strength (room temperature/110 ℃) in Examples 1 to 5 were relatively high. It can be seen that one or more of the characteristics is further increased.

In particular, in the case of direct current dielectric breakdown strength (room temperature/110 ℃), the effect on direct current dielectric breakdown strength was evaluated at room temperature, which is low temperature, and 110 ℃, which is high temperature. For example, in Example 2, the additive polyvinylidene flow Fluoride is easily melt mixed with isotactic polypropylene resin and dispersed within the isotactic polypropylene resin matrix, enabling fluorine dispersion of polyvinylidene fluoride due to improved melt dispersibility and isotactic polypropylene. It serves as a crystal nucleus for crystallization of resin. In other words, the introduction of thermoplastic polyvinylidene fluoride improved the direct current breakdown strength at 110°C.

In summary, the present invention is characterized in that 0.001 to 1.0 phr of a thermoplastic polymer as an additive is melt-mixed with respect to 100 phr of a polymer base, and the thermoplastic polymer is doped with the polymer base to provide insulating properties. According to these characteristics, when thermoplastic polymers are mixed as additives, the distribution of small-sized crystals in the polymer substrate can be improved, thereby effectively improving the insulating properties, and thus, the conventionally used inorganic nanoparticles or organic single molecules-based It is expected that it can replace voltage stabilizers.

The above description is merely an illustrative explanation of the technical idea of the present invention, and various modifications and variations will be possible to those skilled in the art without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for explanation, and the scope of the technical idea of the present invention is not limited by these examples. The scope of protection of the present invention should be interpreted in accordance with the scope of the patent claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of the present invention.

Claims (7)

For 100 phr of polymer substrate,
An insulating composition containing a thermoplastic polymer, characterized in that it has insulating properties by mixing 0.001 to 1.0 phr of the thermoplastic polymer. According to claim 1,
The thermoplastic polymer is,
Polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyphenyline sulfide, polyacetal, polyvinyl acetate, polyacrylate, fluorine-based resin, polyvinylidene fluoride, polyvinyl chloride, acrylic. An insulating composition containing a thermoplastic polymer, characterized in that it is at least one selected from the group consisting of ronitrile-butadiene-styrene rubber, ethylene-based elastomer, and ethylene-propylene rubber. According to claim 1,
The polymer base is,
An insulating composition containing a thermoplastic polymer, characterized in that it is at least one selected from the group consisting of thermoplastic polymer resin and thermosetting polymer resin. According to clause 3,
The thermoplastic polymer resin is,
Polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyphenyline sulfide, polyacetal, polyvinyl acetate, polyacrylate, fluorine-based resin, polyvinylidene fluoride, polyvinyl chloride, acrylic. An insulating composition containing a thermoplastic polymer, characterized in that it is at least one selected from the group consisting of ronitrile-butadiene-styrene rubber, ethylene-based elastomer, and ethylene-propylene rubber. According to clause 3,
The thermosetting polymer resin is,
Contains a thermoplastic polymer, characterized in that it is at least one selected from the group consisting of epoxy resin, phenol resin, melamine resin, phenol resin, furan resin, urea resin, unsaturated ester resin, alkyd resin, polyurethane resin, and silicone rubber resin. An insulating composition. According to claim 1,
An insulating composition containing a thermoplastic polymer, characterized in that the heat distortion temperature of the thermoplastic polymer is a temperature below the melting point of the polymer substrate. According to claim 1,
An insulating composition containing a thermoplastic polymer, characterized in that the thermoplastic polymer has a diameter of 1 to 100 nm and is dispersed in the polymer substrate.