Crosslinked polyethylene insulating material and preparation method thereof

Abstract

The invention relates to the technical field of insulating materials, and discloses a crosslinked polyethylene insulating material which comprises the following components: 40-50 parts of linear low-density polyethylene, 10-20 parts of low-density polyethylene, 3-8 parts of polypropylene resin, 2-3 parts of a silane coupling agent, 0.8-1.5 parts of an initiator and 0.9-1.5 parts of a polycyclic conjugated antioxidant, and further comprises a preparation method of the crosslinked polyethylene insulating material. Comprising the following steps: S1, compounding and pretreating a matrix material, namely mixing low-density polyethylene and linear low-density polyethylene, adding polypropylene resin, an antioxidant and a lubricant, premixing, and drying to form a polyethylene matrix; according to the invention, through a multi-component collaborative design concept, the cross-linked polyethylene insulating material has remarkable advantages in the aspect of electrical performance, and the long-acting stability of the insulating layer material is enhanced, so that the service life of the insulating layer material is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of insulating materials, and particularly to a cross-linked polyethylene insulating material and a preparation method thereof. Background Art

[0002] Cross-linked polyethylene insulating materials play an important role in the manufacture of wires and cables, and can effectively provide electrical isolation to ensure safety and reliability. Compared with traditional uncross-linked polyethylene insulating materials, cross-linked polyethylene has higher heat resistance and mechanical strength, and can withstand higher working temperatures. The cross-linking process can change the structure of polyethylene molecular chains to form a three-dimensional network structure, significantly improving the physical and chemical properties of the material, thereby enhancing the heat resistance and electrical insulation of the material.

[0003] In the field of high-voltage cable insulation, although traditional cross-linked polyethylene insulating materials already have good electrical properties and a certain service life, there are still some problems during their long-term operation. For example, traditional XLPE materials are prone to aging in high-temperature and humid environments, resulting in a decline in electrical properties and a shortening of the service life. In addition, although some existing antioxidant and filler modification technologies can improve the properties of the material to a certain extent, these improvements are usually scattered and lack a systematic optimization scheme, making it difficult to achieve a comprehensive improvement in overall performance. Summary of the Invention

[0004] (I) Technical Problems to be Solved Aiming at the deficiencies of the prior art, the present invention provides a cross-linked polyethylene insulating material and a preparation method thereof, which solve the problems that existing traditional cross-linked polyethylene insulating materials for high-voltage cable insulation are prone to aging in high-temperature and humid environments, resulting in a decline in electrical properties and a shortening of the service life. In addition, although some existing antioxidant and filler modification technologies can improve the properties of the material to a certain extent, these improvements are usually scattered and lack a systematic optimization scheme, making it difficult to achieve a comprehensive improvement in overall performance.

[0005] (II) Technical Solutions To achieve the above object, the present invention provides the following technical solutions: A cross-linked polyethylene insulating material, comprising the following components: 40-50 parts of linear low-density polyethylene, 10-20 parts of low-density polyethylene, 3-8 parts of polypropylene resin, 2-3 parts of silane coupling agent, 0.8-1.5 parts of initiator, 0.9-1.5 parts of polycyclic conjugated antioxidant, 0.8-2 parts of modified nano-aluminum oxide, 1-3 parts of antioxidant, 8-10 parts of carbon black masterbatch, 3-4 parts of ultraviolet absorber, 5-7 parts of catalyst, 0.5-1 part of lubricant, 3-4 parts of voltage stabilizer, and 2-7 parts of cross-linking agent.

[0006] Further, the antioxidant is a combination of a primary antioxidant and a secondary antioxidant. The primary antioxidant is one of vitamin E, antioxidant 300, and antioxidant 1010, and the secondary antioxidant is one of dilauryl thiodipropionate, mannitol, sorbitol, and tris(nonylphenyl) phosphite.

[0007] On the basis of the above, the silane coupling agent is vinyltrimethoxysilane (A2171) or vinyltriethoxysilane.

[0008] As a further aspect of the present invention, the lubricant is a stearate, and the crosslinking agent is dicumyl peroxide.

[0009] On the basis of the above, the voltage stabilizer is one of 5 - oleoyloxy - 1,4 - naphthoquinone, 4 - methyldibenzoyl, and triallyl isocyanurate.

[0010] As a further aspect of the present invention, a method for preparing a cross - linked polyethylene insulating material is also proposed, which includes the following steps: S1: Matrix material compounding and pretreatment: Mix low - density polyethylene and linear low - density polyethylene, add polypropylene resin, add antioxidants and lubricants, and after premixing, perform drying treatment to form a polyethylene matrix. S2: Nano - reinforcement and functionalized dispersion of stabilizers: Uniformly disperse modified nano - alumina into the polyethylene matrix through melt blending technology to prevent nanoparticle agglomeration, add a voltage stabilizer, and perform surface coating treatment. S3: Preparation of cross - linking material A: Add a silane coupling agent and an initiator to a twin - screw extruder, control the temperature at 140 - 160 °C, and achieve grafting of silane and polyethylene through a free - radical reaction to form a cross - linkable grafted material. Then add a polycyclic conjugated antioxidant and a cross - linking agent and stir evenly to obtain material A. S4: Preparation of catalytic masterbatch: Mix a catalyst with an ultraviolet absorber and a carbon black masterbatch and granulate to form a catalytic masterbatch, i.e., material B. S5: Mixing and extrusion: Mix material A and material B in a ratio of 9:1 and form an insulating layer through an extruder.

[0011] S6: Removal of by - products: Use vacuum drying or hot - air circulation to remove cross - linking by - products such as water and alcohols, and dynamically adjust the curing time to 48 - 72 hours according to the thickness of the insulating layer to avoid the formation of internal defects.

[0012] Further, the preparation method of the modified nano-aluminum oxide is as follows: Mix nano-aluminum oxide with a particle size of 50-100 nm and absolute ethanol at a mass ratio of 1:10, and ultrasonically disperse for 35-40 min until a uniform suspension is formed. Then add o-xylene and continue ultrasonic treatment for 18-20 min. Evaporate ethanol by heating in an oil bath at 70-75 °C to obtain an o-xylene suspension. Gradually add 3-aminopropyltriethoxysilane dropwise to the suspension, and the addition amount is 2.5-3% of the mass of nano-aluminum oxide. Adjust the pH to 5, which can be controlled by 0.1 M hydrochloric acid. Reflux in a water bath at 60 °C for 2-2.3 hours, and the rotation speed of synchronous mechanical stirring is 300-320 rpm to promote the hydrolysis of KH550 and the condensation with the hydroxyl groups on the alumina surface. Then raise the temperature to 80 °C to evaporate o-xylene and vacuum dry for 10-12 hours at a temperature of 58-60 °C to obtain a silylated intermediate product. Then disperse the silylated intermediate product in absolute ethanol, add 4,4'-diaminodiphenyl sulfone and polyethylene glycol-2000, and ultrasonically treat at 50 °C for 0.9-1 hour to make the DDS amino group react with the terminal amino group of KH550 and the PEG hydroxyl group bond to the alumina surface. After filtration, wash with ethanol 3 times and vacuum dry at 60 °C for 24 hours to obtain modified nano-aluminum oxide with surface-grafted organic functional groups.

[0013] On the basis of the above, the melt blending in S2 is controlled at three stages. The feeding section is 120-140 °C, the melting section is 60-180 °C, and the extrusion section is 140-150 °C. (III) Beneficial effects Compared with the prior art, the present invention provides a cross-linked polyethylene insulating material, its preparation method and its application in automotive anti-corrosion, and has the following beneficial effects: 1. Through the concept of multi-component collaborative design, that is, by combining a new type of voltage stabilizer, a primary and secondary antioxidant system, nano-filler modification and precise process control, the present invention realizes a comprehensive improvement in electrical performance and significantly enhances the long-term stability. Especially through the combination of a lubricant and a cross-linking agent, it not only ensures the smoothness during the processing, but also effectively controls the cross-linking density and improves the overall quality of the material. Therefore, the present invention not only shows significant advantages in electrical performance, but also its service life is extended, thus providing a more reliable choice for the application of high-voltage cable insulating materials.

[0014] 2. Through the synergistic use of a primary antioxidant and a secondary antioxidant, through a multi-path mechanism of free radical capture-peroxide decomposition-metal passivation, the present invention realizes a comprehensive improvement in the heat-oxygen aging resistance, electrical properties and mechanical stability of the material.

[0015] 3. In the present invention, 5 - oleoyloxy - 1,4 - naphthoquinone containing a polycyclic conjugated structure is used as a voltage stabilizer, which can efficiently consume the energy of high - energy electrons, significantly improve the electrical resistance performance of the material, and solve the problem of easy migration loss of traditional stabilizers. The combination of carbon black masterbatch and ultraviolet absorber meets the long - term stability of overhead cables in humid and ultraviolet environments. The polycyclic conjugated antioxidant significantly improves the electrical breakdown resistance and thermal - oxidative stability of cross - linked polyethylene insulating materials through a dual mechanism of free - radical capture - charge neutralization, reduces space charge accumulation, and improves the electrical breakdown resistance performance of the material. When compounded with a cross - linking agent, it inhibits thermal - oxidative degradation during high - temperature processing and long - term operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic flow structure diagram of a preparation method of a cross - linked polyethylene insulating material in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0018] Example 1 Refer to Figure 1 , a cross - linked polyethylene insulating material, comprising the following components: 40 parts of linear low - density polyethylene, 10 parts of low - density polyethylene, 3 parts of polypropylene resin, 2 parts of silane coupling agent, 0.8 part of initiator, 1 part of polycyclic conjugated antioxidant, 1 part of modified nano - alumina, 2 parts of antioxidant, 8 parts of carbon black masterbatch, 3 parts of ultraviolet absorber, 5 parts of catalyst, 0.5 part of lubricant, 3 parts of voltage stabilizer, 2 parts of cross - linking agent. The antioxidant uses the cooperation of a main antioxidant and a co - antioxidant. The main antioxidant is vitamin E, and the co - antioxidant is sorbitol. The silane coupling agent is vinyltrimethoxysilane (A2171), the lubricant is stearate, which prevents moisture interference in the cross - linking reaction during processing and optimizes the extrusion processing performance. The cross - linking agent is dicumyl peroxide, and the voltage stabilizer is 5 - oleoyloxy - 1,4 - naphthoquinone. As a new type of voltage stabilizer, 5 - oleoyloxy - 1,4 - naphthoquinone significantly improves the electrical resistance of cross - linked polyethylene by quickly consuming the energy of high - energy electrons, and at the same time reduces migration loss during production, storage, and use.

[0019] The present invention also proposes a preparation method of a cross - linked polyethylene insulating material, comprising the following steps: S1: Matrix material compounding and pretreatment: Mix low-density polyethylene with linear low-density polyethylene, add polypropylene resin to improve heat resistance, add antioxidants and lubricants, and perform drying treatment after premixing to form a polyethylene matrix, avoiding moisture interference with subsequent reactions; S2: Nano-enhancement and functionalized dispersion of stabilizers: Uniformly disperse modified nano-aluminum oxide into the polyethylene matrix through melt blending technology to prevent nanoparticle agglomeration. Add a voltage stabilizer and perform surface coating treatment to reduce the migration loss of the voltage stabilizer during subsequent use, ensuring its stable functioning and guaranteeing the performance stability and reliability of the material system. The melt blending is divided into three sections for temperature control. The feeding section is at 120 °C to avoid premature melting of the material and resulting agglomeration. The melting section is at 60 °C to achieve sufficient melting and mixing of the polymer and the stabilizer. The extrusion section is at 140 °C to reduce the damage of the shear force to the coating layer structure; S3: Preparation of crosslinking A material: Add a silane coupling agent and an initiator to a twin-screw extruder, control the temperature at 140 °C, and achieve grafting of silane and polyethylene through a free radical reaction to form a crosslinkable grafted material. Then add a polycyclic conjugated antioxidant and a crosslinking agent and stir evenly to obtain A material; S4: Preparation of catalytic masterbatch: Mix a catalyst with an ultraviolet absorber and a carbon black masterbatch and granulate to produce a catalytic masterbatch, i.e., B material; S5: Mixing and extrusion: Mix material A and material B in a ratio of 9:1 and form an insulating layer through an extruder.

[0020] S6: By-product removal: Use vacuum drying or hot air circulation to remove crosslinking by-products such as water and alcohols. Dynamically adjust the curing time to 48 hours according to the thickness of the insulating layer to avoid the formation of internal defects.

[0021] It should be noted that the preparation method of the modified nano-aluminum oxide is as follows: Mix nano-aluminum oxide with a particle size of 50 nm and absolute ethanol in a mass ratio of 1:10, and ultrasonically disperse for 35 min to form a uniform suspension. Then add o-xylene and continue ultrasonic treatment for 18 min. Evaporate ethanol by heating in an oil bath at 70 °C to obtain an o-xylene suspension. Dropwise add 3-aminopropyltriethoxysilane to the suspension, and the addition amount is 2.5% of the mass of nano-aluminum oxide. Adjust the pH to 5, which can be controlled by 0.1 M hydrochloric acid. Carry out water bath reflux at 60 °C for 2 hours, and the rotation speed of synchronous mechanical stirring is 300 rpm to promote the hydrolysis of KH550 and its condensation with the hydroxyl groups on the surface of aluminum oxide. Then raise the temperature to 80 °C to evaporate o-xylene, and carry out vacuum drying for 10 hours at a temperature of 58 °C to obtain a silylated intermediate product. Then disperse the silylated intermediate product in absolute ethanol, add 4,4'-diaminodiphenyl sulfone and polyethylene glycol-2000, and carry out ultrasonic treatment at 50 °C for 0.9 hours to make the DDS amino group react with the terminal amino group of KH550, and the PEG hydroxyl group bond with the surface of aluminum oxide. After filtration, wash with ethanol 3 times, and carry out vacuum drying at 60 °C for 24 hours to obtain the modified nano-aluminum oxide with surface-grafted organic functional groups.

[0022] Example 2 Refer to Figure 1 , a cross-linked polyethylene insulating material, comprising the following components: 50 parts of linear low-density polyethylene, 20 parts of low-density polyethylene, 8 parts of polypropylene resin, 3 parts of silane coupling agent, 1.5 parts of initiator, 1.5 parts of polycyclic conjugated antioxidant, 2 parts of modified nano-aluminum oxide, 3 parts of antioxidant, 10 parts of carbon black masterbatch, 4 parts of ultraviolet absorption inhibitor, 7 parts of catalyst, 1 part of lubricant, 4 parts of voltage stabilizer, 7 parts of cross-linking agent. The antioxidant adopts the cooperation of a main antioxidant and a co-antioxidant. The main antioxidant is antioxidant 1010, and the co-antioxidant is tris(nonylphenyl) phosphite. The silane coupling agent is vinyltriethoxysilane, and the lubricant is stearate to prevent moisture interference in the cross-linking reaction during processing and optimize the extrusion processing performance. The cross-linking agent is dicumyl peroxide, and the voltage stabilizer is 4-methyldibenzophenone.

[0023] The present invention also provides a preparation method of a cross-linked polyethylene insulating material, comprising the following steps: S1: Matrix material compounding and pretreatment. Mix low-density polyethylene and linear low-density polyethylene, add polypropylene resin to improve heat resistance, add antioxidant and lubricant, and carry out drying treatment after premixing to form a polyethylene matrix to avoid moisture interference in subsequent reactions; S2: Nano-enhancement and stabilizer functionalization and dispersion. The modified nano-aluminum oxide is evenly dispersed into the polyethylene matrix through a melt blending technique to prevent nanoparticle agglomeration. A voltage stabilizer is added, and surface coating treatment is carried out to reduce the migration loss of the voltage stabilizer during subsequent use, ensuring its stable functioning and guaranteeing the performance stability and reliability of the material system; S3: Preparation of crosslinked material A. A silane coupling agent and an initiator are added to a twin-screw extruder, and the temperature is controlled at 140 - 160 °C. Through a free radical reaction, grafting of silane and polyethylene is achieved to form a crosslinkable grafted material. Then, a polycyclic conjugated antioxidant and a crosslinking agent are added and stirred evenly to obtain material A; S4: Preparation of catalytic masterbatch. A catalyst, an ultraviolet absorber, and a carbon black masterbatch are mixed and granulated to prepare a catalytic masterbatch, namely material B; S5: Mixing and extrusion. Material A and material B are mixed in a ratio of 9:1 and formed into an insulating layer through an extruder.

[0024] S6: By-product removal. Vacuum drying or hot air circulation is used to remove crosslinking by-products such as water and alcohols. The curing time is dynamically adjusted to 72 hours according to the thickness of the insulating layer to avoid the formation of internal defects.

[0025] It should be noted that the preparation method of the modified nano-aluminum oxide is as follows: Nano-aluminum oxide with a particle size of 100 nm is mixed with absolute ethanol at a mass ratio of 1:10, and ultrasonically dispersed for 40 min to form a uniform suspension. Then, o-xylene is added, and ultrasonic treatment is continued for 20 min. Ethanol is evaporated by heating in an oil bath at 75 °C to obtain an o-xylene suspension. 3-aminopropyltriethoxysilane is added dropwise to the suspension, and the addition amount is 3% of the mass of nano-aluminum oxide. The pH is adjusted to 5, which can be controlled by 0.1 M hydrochloric acid. It is refluxed in a water bath at 60 °C for 2.3 hours, and the rotational speed of synchronous mechanical stirring is 320 rpm to promote the hydrolysis of KH550 and the condensation with the hydroxyl groups on the surface of aluminum oxide. Then, the temperature is raised to 80 °C to evaporate o-xylene, and vacuum dried for 12 hours at a temperature of 60 °C to obtain a silylated intermediate product. The silylated intermediate product is then dispersed in absolute ethanol, and 4,4'-diaminodiphenyl sulfone and polyethylene glycol-2000 are added. Ultrasonic treatment is carried out at 50 °C for 1 hour to make the DDS amino group react with the terminal amino group of KH550, and the PEG hydroxyl group bond to the surface of aluminum oxide. After filtration, it is washed 3 times with ethanol and vacuum dried at 60 °C for 24 hours to obtain modified nano-aluminum oxide with surface-grafted organic functional groups. In S2, the melt blending is temperature-controlled in three stages. The feeding section is at 40 °C to avoid premature melting of the material and resulting in agglomeration. The melting section is at 180 °C to achieve sufficient melting and mixing of the polymer and the stabilizer. The extrusion section is at 150 °C to reduce the damage of the shear force to the structure of the coating layer.

[0026] The present invention further includes a controller, a voice receiver, and an operating device. The voice receiver is electrically connected to the controller, and the controller is electrically connected to the operating device. The voice receiver receives the external operating voice information and sends the operation signal of the operating voice information to the controller, and the controller controls the operating device to execute the operation signal.

[0027] In the description herein, it should be noted that relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0028] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A cross-linked polyethylene insulating material, characterized in that, It includes the following components: 40 - 50 parts of linear low density polyethylene, 10 - 20 parts of low density polyethylene, 3 - 8 parts of polypropylene resin, 2 - 3 parts of silane coupling agent, 0.8 - 1.5 parts of initiator, 0.9 - 1.5 parts of polycyclic conjugated antioxidant, 0.8 - 2 parts of modified nano-aluminum oxide, 1 - 3 parts of antioxidant, 8 - 10 parts of carbon black masterbatch, 3 - 4 parts of ultraviolet absorber, 5 - 7 parts of catalyst, 0.5 - 1 part of lubricant, 3 - 4 parts of voltage stabilizer, 2 - 7 parts of crosslinking agent.

2. The cross-linked polyethylene insulating material according to claim 1, characterized in that The antioxidant adopts the cooperation of a primary antioxidant and a secondary antioxidant. The primary antioxidant is one of vitamin E, antioxidant 300 and antioxidant 1010, and the secondary antioxidant is one of dilauryl thiodipropionate, mannitol, sorbitol and tris(nonylphenyl) phosphite.

3. The cross-linked polyethylene insulating material according to claim 2, characterized in that, The silane coupling agent is vinyltrimethoxysilane (A2171) or vinyltriethoxysilane.

4. A cross-linked polyethylene insulating material according to claim 1, characterized in that, The lubricant is stearate, and the crosslinking agent is dicumyl peroxide.

5. A crosslinked polyethylene insulating material according to claim 1, characterized in that, The voltage stabilizer is one of 5 - oleoyloxy-1,4-naphthoquinone, 4 - methyldibenzoyl methane and triallyl isocyanurate.

6. The preparation method of a cross-linked polyethylene insulating material according to claim 1, characterized in that, It includes the following steps: S1: Matrix material compounding and pretreatment. Mix low density polyethylene and linear low density polyethylene, add polypropylene resin, add antioxidant and lubricant, and after premixing, conduct drying treatment to form a polyethylene matrix. S2: Nano-enhancement and functionalized dispersion of stabilizer. Uniformly disperse the modified nano-aluminum oxide into the polyethylene matrix through melt blending technology to prevent nanoparticle agglomeration, add the voltage stabilizer, and conduct surface coating treatment. S3: Preparation of crosslinking A material. Add the silane coupling agent and initiator into a twin-screw extruder, control the temperature at 140 - 160 °C, and achieve the grafting of silane and polyethylene through a free radical reaction to form a crosslinkable grafted material, and then add the polycyclic conjugated antioxidant and crosslinking agent and stir evenly to obtain material A. S4: Preparation of catalytic masterbatch. Mix the catalyst with the ultraviolet absorber and carbon black masterbatch and granulate to make the catalytic masterbatch, that is, material B. S5: Mixing and extrusion. Mix material A and material B in a ratio of 9:1 and form an insulating layer through an extruder. S6: Removal of by-products. Adopt vacuum drying or hot air circulation to remove crosslinking by-products such as water and alcohols, and dynamically adjust the curing time to 48 - 72 hours according to the thickness of the insulating layer to avoid the formation of internal defects.

7. The preparation method of a crosslinked polyethylene insulating material according to claim 6, characterized in that, The preparation method of the modified nano-aluminum oxide is as follows: Mix nano-aluminum oxide with a particle size of 50-100 nm and absolute ethanol in a mass ratio of 1:10, and ultrasonically disperse for 35-40 min until a uniform suspension is formed. Then add o-xylene and continue ultrasonic treatment for 18-20 min. Evaporate ethanol by heating in an oil bath at 70-75 °C to obtain an o-xylene suspension. Dropwise add 3-aminopropyltriethoxysilane to the suspension, and the addition amount is 2.5-3% of the mass of nano-aluminum oxide. Adjust the pH to 5, which can be controlled by 0.1 M hydrochloric acid. Carry out water bath reflux at 60 °C for 2-2.3 hours, and the rotation speed of synchronous mechanical stirring is 300-320 rpm to promote the hydrolysis of KH550 and the condensation with the hydroxyl groups on the alumina surface. Then raise the temperature to 80 °C to evaporate o-xylene, and carry out vacuum drying for 10-12 hours at a temperature of 58-60 °C to obtain a silylated intermediate product. Then disperse the silylated intermediate product in absolute ethanol, add 4,4'-diaminodiphenyl sulfone and polyethylene glycol-2000, and carry out ultrasonic treatment at 50 °C for 0.9-1 hour to make the DDS amino group react with the terminal amino group of KH550 and the PEG hydroxyl group bond with the alumina surface. After filtration, wash with ethanol 3 times and carry out vacuum drying at 60 °C for 24 hours to obtain modified nano-aluminum oxide with surface-grafted organic functional groups.

8. The preparation method of a cross-linked polyethylene insulating material according to claim 6, characterized in that, In the melt blending in S2, the temperature is controlled in three stages. The feeding section is 120-140 °C, the melting section is 60-180 °C, and the extrusion section is 140-150 °C.

Images