Ultraviolet crosslinking TPE (thermoplastic elastomer) insulating material capable of resisting temperature of 150 DEG C and preparation method thereof

Abstract

The invention relates to the technical field of cable materials, and particularly discloses a 150 DEG C-resistant ultraviolet crosslinking TPE insulating material and a preparation method thereof. The invention discloses an ultraviolet crosslinking TPE (thermoplastic elastomer) insulating material capable of resisting temperature of 150 DEG C. The ultraviolet crosslinking TPE insulating material comprises the following components in parts by weight: 100 parts of SEBS (styrene-ethylene-butylene-styrene) resin, 15-30 parts of EPDM (ethylene-propylene-diene monomer) rubber, 10-15 parts of KN resin, 1-2 parts of a photoinitiator, 1.5-2.5 parts of a crosslinking agent and 1.2-1.8 parts of an antioxidant, the KN resin is polyolefin resin with the density of 0.880-0.908 g / cm < 3 >, and the melt index of the KN resin is 3-18 g / 10 min. The insulation material provided by the invention can realize on-line rapid crosslinking through UV-LED irradiation equipment after being extruded, the production period is short, the efficiency is high, the energy consumption is low, and a cable prepared from the cable material has the characteristics of softness, high tensile strength and good thermal extension performance, and can meet the standard requirement of resisting the temperature of 150 DEG C.

Description

Technical Field

[0001] The present application relates to the technical field of cable materials, and more specifically, to a 150°C temperature-resistant ultraviolet light cross-linked TPE insulating material and a preparation method thereof. Background Art

[0002] For flexible cables such as mining cables, welding machine cables, marine cables, wind power cables, etc., the insulation material must be soft, high temperature resistant, and have good insulation properties. Cross-linked EPDM rubber insulation or silicone rubber insulation is usually used.

[0003] It is well known that polymer materials can improve their high temperature resistance and crack resistance after cross-linking. The main cross-linking methods for cable materials are sulfur wire (or peroxide cross-linking), electron accelerator irradiation cross-linking, silane cross-linking, and ultraviolet irradiation cross-linking. Among them, electron beam irradiation cross-linking requires the extruded wires and cables to be irradiated by irradiation equipment before cross-linking. The equipment is expensive, with a large one-time investment, and there are problems such as safety protection during the operation of electron beam irradiation equipment. Silane cross-linking requires boiling or steam cross-linking, and the boiling process will lead to the problem of increasing the product production cycle. In recent years, ultraviolet cross-linking technology has been widely used in the field of cross-linked polyethylene insulation materials for wires and cables. Compared with the above cross-linking process, ultraviolet cross-linking technology can achieve online rapid cross-linking, and has the characteristics of short production cycle, high efficiency and low energy consumption, but it has not yet been widely used in cross-linked soft insulating cable materials.

[0004] The existing cross-linking process of EPDM insulation materials has low production efficiency and high energy consumption. It is difficult for EPDM containing a large amount of inorganic reinforcing fillers to allow ultraviolet light to pass through and cross-link. Patent application CN14085482A discloses a UV-crosslinked low-voltage EPDM insulation material and its preparation method. The insulation material uses nano-silicon dioxide as a reinforcing agent to improve the mechanical properties and keep the material transparent, ensuring the transmittance of ultraviolet light. However, the material of the invention requires 11-13S of ultraviolet light irradiation time, low light cross-linking efficiency, and the material can only pass the 135℃×168h thermal aging test, which only meets the standard requirements of insulation materials with a temperature resistance level of 90℃.

[0005] TPE materials are usually prepared by blending SEBS with PP and other resins after oil filling. They have excellent rubber elasticity, excellent weather resistance, low temperature resistance, heat aging resistance and other characteristics. Thermoplastic TPE materials have been used in the field of cables with low temperature resistance requirements. There are 150℃ irradiation cross-linked halogen-free flame-retardant TPEs on the market, which are used in high-voltage cables in electric vehicles with halogen-free flame-retardant requirements. However, there are no related reports and applications of UV cross-linked TPE.

[0006] There are tertiary carbon atoms in the PP molecular chain structural units in the TPE component, which are significantly degraded under ultraviolet light irradiation, making it difficult to form a cross-linked structure. SEBS is usually filled with a large amount of white oil to improve the processing fluidity of TPE, but white oil does not participate in the cross-linking reaction and also has a serious impact on the ultraviolet light cross-linking of TPE. On the other hand, white oil has poor heat resistance and significant thermal weight loss at high temperatures. The upper limit of the operating temperature of thermoplastic TPE is usually 125-135°C, which cannot meet the 150°C usage requirement, let alone pass the 200°C thermal extension test in the cross-linked cable standard.

[0007] In summary, it is very necessary to provide a solution for preparing a 150°C temperature-resistant cross-linked TPE insulating material using a UV cross-linking process. Summary of the invention

[0008] In order to overcome the above-mentioned technical problems, the present application provides a 150°C temperature-resistant UV-cross-linked TPE insulating material and a preparation method thereof. The insulating material provided by the present application can be quickly cross-linked online through UV-LED irradiation equipment after extrusion, with a short production cycle, high efficiency and low energy consumption. The cable sheath prepared from the cable material has the characteristics of softness, high tensile strength and good thermal elongation performance, and can meet the standard requirement of temperature resistance of 150°C.

[0009] In order to achieve the above technical objectives, the present application provides a 150°C temperature-resistant UV-crosslinked TPE insulating material, which adopts the following technical solution: A 150°C temperature-resistant ultraviolet cross-linked TPE insulating material, comprising the following components in parts by weight: 100 parts of SEBS resin, 15-30 parts of EPDM rubber, 10-15 parts of KN resin, 1-2 parts of photoinitiator, 1.5-2.5 parts of cross-linking agent, and 1.2-1.8 parts of antioxidant; The styrene content of the SEBS resin is 13-20%, and the melt index is 3-6 g / 10 min; The EPDM rubber is a terpolymer copolymerized by ethylene, propylene and ENB, wherein the ethylene content is 65-75% and the ENB content is 4-6%; The KN resin has a density of 0.880-0.908 g / cm 3 The polyolefin resin has a melt index of 3-18g / 10min.

[0010] By adopting the above technical solution, SEBS resin with high styrene content is in powder form and needs to be filled with white oil for processing. The present application adopts granular SEBS with low styrene content as the main resin. The formula does not contain white oil and PP resin, has no adverse effect on UV cross-linking, has good fluidity, and eliminates the oil filling step, thereby improving production efficiency. The present application adds EPDM rubber with high ethylene content to the SEBS resin, provides a third cross-linking monomer as an auxiliary cross-linking point, and combines with a multi-functional cross-linking agent to obtain a very high cross-linking efficiency and degree of cross-linking under the initiation of a high-efficiency photoinitiator. The KN resin added in the present application has low crystallinity, high strength and excellent processing fluidity, and has good compatibility with SEBS resin and EPDM rubber. The blend can maintain a good transparent state in a molten state, which is conducive to further improving the production efficiency of UV cross-linking.

[0011] More preferably, the photoinitiator is one or more combinations of benzophenone, triphenylphosphine oxide, and benzoin diethyl ether.

[0012] Preferably, the photoinitiator is a mixture of benzophenone and triphenylphosphine oxide in a mass ratio of 3:1.

[0013] By adopting the above technical solution, the preferred photoinitiator of the present application can ensure that the resins and rubbers in the formula can be completely cross-linked and quickly cross-linked, which is manifested in that the product has higher mechanical properties on a macro scale.

[0014] More preferably, the crosslinking agent is one or more combinations of triallyl isocyanurate, trimethylolpropane trimethacrylate, and trimethylolpropane acrylate.

[0015] Preferably, the cross-linking agent is a mixture of triallyl isocyanurate and trimethylolpropane trimethacrylate in a mass ratio of 1:2.

[0016] By adopting the above technical solution, the preferred cross-linking agent of the present application can ensure that the resins and rubbers in the formula can be completely cross-linked and quickly cross-linked, which is manifested in that the product has higher mechanical properties on a macro scale.

[0017] More preferably, the antioxidant is one or more combinations of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol, thioethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-mercaptomethylbenzimidazole zinc salt, and tris[2,4-di-tert-butylphenyl]phosphite.

[0018] Preferably, the antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and ethylenedithiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] in a mass ratio of 3:2.

[0019] By adopting the above technical solution, the above preferred antioxidant combination can greatly improve the heat resistance of the formula, ensuring that the formula can meet the use requirement of 150°C after UV-LED irradiation cross-linking.

[0020] The present application also provides a method for preparing a 150°C temperature-resistant UV-crosslinked TPE insulating material, which adopts the following technical solution: A method for preparing a 150°C temperature-resistant ultraviolet cross-linked TPE insulating material comprises the following steps: S1, SEBS resin, EPDM rubber, KN resin, photoinitiator, crosslinking agent and antioxidant are mixed, and kneaded at 210° C. for 10-15 minutes to obtain a mixture; S2, extruding and granulating the mixed material in an extruder to obtain the 150° C. temperature-resistant UV-crosslinked TPE insulating material.

[0021] By adopting the above technical scheme, the formula provided in the present application does not require sulfur-linking equipment, electron irradiation or boiling steam cross-linking during ultraviolet light cross-linking. After the cable material is extruded, it can be quickly cross-linked online through UV-LED irradiation equipment, with a short production cycle, high efficiency and low energy consumption.

[0022] In summary, this application has the following beneficial effects: (1) The present application uses a special variety of SEBS as the main resin, and does not need to be filled with white oil or PP resin, thereby avoiding the adverse effects of white oil and PP resin on UV cross-linking. By adding EPDM with a high ethylene content (65-75%), a third cross-linking monomer is provided as an auxiliary cross-linking point, which is combined with a multifunctional cross-linking agent to obtain a very high cross-linking efficiency and degree under the initiation of a high-efficiency photoinitiator. (2) The addition of KN resin can improve the compatibility of SEBS resin and EPDM rubber, the transparency and fluidity under high temperature irradiation conditions, thereby improving the smoothness of the surface of the product after curing, and the cross-linking speed during UV curing. Therefore, a faster cross-linking speed can ensure the mechanical properties of the product after curing; (3) The preferred crosslinking agent and photoinitiator of the present application can ensure that the resins and rubbers in the formula can be completely crosslinked and crosslinked quickly, which is manifested in that the product has high mechanical properties on a macro scale; the preferred antioxidant of the present application can greatly improve the heat resistance of the formula, ensuring that the formula can meet the use requirement of 150°C after UV-LED irradiation crosslinking; (4) The formula provided in the present application does not require sulfur-linking equipment, electron irradiation or boiling steam cross-linking when cross-linking by ultraviolet light. After the cable material is extruded, it can be quickly cross-linked online through UV-LED irradiation equipment, with a short production cycle, high efficiency and low energy consumption. DETAILED DESCRIPTION

[0023] The present application is further described in detail below with reference to the embodiments.

[0024] A 150°C temperature-resistant ultraviolet cross-linked TPE insulating material comprises the following components in parts by weight: 100 parts of SEBS resin, 15-30 parts of EPDM rubber, 10-15 parts of KN resin, 1-2 parts of photoinitiator, 1.5-2.5 parts of cross-linking agent and 1.2-1.8 parts of antioxidant.

[0025] The preparation steps are: S1, SEBS resin, EPDM rubber, KN resin, photoinitiator, crosslinking agent and antioxidant are mixed, and kneaded at 210° C. for 10-15 minutes to obtain a mixture; S2, extruding and granulating the mixed material in an extruder to obtain the 150° C. temperature-resistant UV-crosslinked TPE insulating material.

[0026] The styrene content of the SEBS resin is 13-20%, and the melt index is 3-6 g / 10 min. Specific optional resin grades include Asahi Kasei H1062, Asahi Kasei H1052 or Kraton G1645.

[0027] The EPDM rubber is a terpolymer copolymerized by ethylene, propylene and ENB, wherein the ethylene content is 65-75% and the ENB content is 4-6%. Specific rubber grades available include ExxonMobil Vistalon 7001, Sinopec Mitsui 3092PM or Sinopec Mitsui 3112PM.

[0028] The KN resin has a density of 0.880-0.908 g / cm 3 The polyolefin resin has a melt index of 3-18g / 10min. The specific optional resin grades are Japan Mitsubishi KS560T, Japan Mitsubishi KS340T or Japan Mitsubishi KS571. Example

[0029] Example 1 A 150°C temperature-resistant UV-crosslinked TPE insulating material comprises the following components by mass: 100kg of SEBS resin (Asahi Kasei H1062), 15kg of EPDM rubber (ExxonMobil Vistalon 7001), 10kg of KN resin (Mitsubishi KS560T), 1kg of photoinitiator, 2kg of crosslinking agent, and 1.6kg of antioxidant.

[0030] The photoinitiator is benzophenone, the crosslinking agent is trimethylolpropane trimethacrylate, and the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0031] And prepared by the following steps: S1, SEBS resin, EPDM rubber, KN resin, photoinitiator, crosslinking agent and antioxidant are mixed and added into an internal mixer, and mixed at 210° C. for 10 min to obtain a mixture; S2, extruding the mixed material into granules in a single screw extruder, wherein the temperatures of the various sections of the single screw extruder are 170°C, 190°C, 210°C, and 220°C, respectively, and the head temperature is 230°C, to obtain the 150°C temperature-resistant UV-crosslinked TPE insulating material.

[0032] Example 2 A 150°C temperature-resistant UV-crosslinked TPE insulating material, the preparation steps of which are the same as those of Example 1, and the difference from Example 1 is that the components and amounts are different, specifically: 100kg of SEBS resin (Asahi Kasei H1052), 20kg of EPDM rubber (Sinopec Mitsui 3092PM), 13kg of KN resin (Japan Mitsubishi KS340T), 2kg of photoinitiator, 1.5kg of crosslinking agent, and 1.8kg of antioxidant.

[0033] The photoinitiator is benzophenone, the crosslinking agent is trimethylolpropane trimethacrylate, and the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0034] Example 3 A 150°C temperature-resistant UV-crosslinked TPE insulating material, the preparation steps are the same as those in Example 1, and the difference from Example 1 is that the components and amounts are different, specifically: 100kg of SEBS resin (Kraton G1645), 30kg of EPDM rubber (Sinopec Mitsui 3112PM), 15kg of KN resin (Japan Mitsubishi KS571), 1.5kg of photoinitiator, 2.5kg of crosslinking agent, and 1.2kg of antioxidant.

[0035] The photoinitiator is benzophenone, the crosslinking agent is trimethylolpropane trimethacrylate, and the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0036] Example 4 A 150°C temperature-resistant UV-crosslinked TPE insulating material, the component dosage and preparation steps are the same as those of Example 1, and the difference from Example 1 is that the photoinitiator is a mixture of benzophenone and triphenylphosphine oxide in a mass ratio of 3:1.

[0037] Example 5 A 150°C temperature-resistant UV-crosslinked TPE insulating material, the component dosage and preparation steps are the same as those of Example 1, and the difference from Example 1 is that the photoinitiator is a mixture of benzophenone, triphenylphosphine oxide and benzoin diethyl ether in a mass ratio of 1:1:1.

[0038] Example 6 A 150°C temperature-resistant UV-crosslinked TPE insulating material, the component dosage and preparation steps are the same as those of Example 1, and the difference from Example 1 is that the crosslinking agent is a mixture of triallyl isocyanurate and trimethylolpropane trimethacrylate in a mass ratio of 1:2.

[0039] Example 7 A 150°C temperature-resistant UV-crosslinked TPE insulating material, which is different from Example 1 in that the antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and ethylenedithiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] in a mass ratio of 3:2.

[0040] Comparative Example Comparative Example 1 A UV-crosslinked TPE insulating material, the preparation steps of which are the same as those of Example 1, and the difference from Example 1 is that EPDM rubber is not added to the formula.

[0041] Comparative Example 2 A UV-crosslinked TPE insulating material, the preparation steps of which are the same as those of Example 1, and the difference from Example 1 is that KN resin is not added to the formula.

[0042] Comparative Example 3 A UV-crosslinked TPE insulating material, the preparation steps of which are the same as those of Example 1, except that the amount of antioxidant added is adjusted to 0.6 kg.

[0043] Performance testing The UV-crosslinked TPE insulating materials prepared in the above embodiments and comparative examples were tested after being irradiated by UV-LED equipment. The light power during irradiation was 4W / cm 2 , the UV wavelength is 365nm, the irradiation time is 1s, and the irradiation speed is 60m / min. The performance of the product after UV cross-linking is tested and the test results are recorded in Table 1 below.

[0044] Table 1 Performance test results It can be seen from the test results in Table 1 that Examples 1-7 provided in the present application can achieve rapid crosslinking under ultraviolet irradiation, the crosslinked samples are soft, have high tensile strength, good thermal elongation performance, and the gel content can reach more than 75%. The air heat aging test shows that the crosslinked materials can meet the standard requirement of temperature resistance of 150°C. In the actual production process, the cable material provided in the present application can be crosslinked online through UV-LED equipment after extrusion, and the crosslinking speed can reach 100m / min. Both the inner and outer layers of the cable can be crosslinked, and various performance indicators can meet the relevant requirements of crosslinked cable insulation materials.

[0045] Comparing Example 1 and Example 4-7, Example 4-7 is compared with Example 1, and the composition of the photoinitiator, crosslinker, and antioxidant are changed respectively. It can be seen that the performance of Examples 4-7 is improved to varying degrees, and the performance of Example 7 is the best, which is the best example. In summary, the best composition of the photoinitiator is: benzophenone: triphenylphosphine oxide = 3:1; the best composition of the crosslinker is: triallyl isocyanurate: trimethylolpropane trimethacrylate = 1:2; the best composition of the antioxidant is: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], ethylenedithiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] = 3:2.

[0046] Comparing Example 1 and Comparative Example 1, the formula of Comparative Example 1 does not add EPDM rubber, and the UV cross-linking efficiency is significantly reduced. The thermal elongation is 200%, which is much larger than the standard requirement of 175%, while the gel content is only 54%, which is less than the standard requirement of 60% of the gel content of the cross-linked insulating material (refer to the standard of silane cross-linked polyethylene insulating material).

[0047] Comparing Example 1 and Comparative Example 2, KN resin was not added to the formula of Comparative Example 2, and the tensile strength was obviously low. The UV cross-linking performance was not affected, but the processing performance was poor. Under the same wire laying process, the wire surface was rough and not smooth.

[0048] Comparing Example 1 and Comparative Example 3, the formula of Comparative Example 3 reduces the amount of antioxidant used, and the irradiated sample cannot pass the 180°C × 168h heat aging test and cannot meet the standard requirement of temperature resistance of 150°C.

[0049] The above is only the preferred implementation of the present application. The protection scope of the present application is not limited to the above embodiments. All technical solutions under the concept of the present application belong to the protection scope of the present application. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present application should also be regarded as the protection scope of the present application.

Claims

1. A 150°C temperature-resistant UV-crosslinked TPE insulating material, characterized in that: The invention comprises the following components in parts by weight: 100 parts of SEBS resin, 15-30 parts of EPDM rubber, 10-15 parts of KN resin, 1-2 parts of photoinitiator, 1.5-2.5 parts of crosslinking agent, and 1.2-1.8 parts of antioxidant; The styrene content of the SEBS resin is 13-20%, and the melt index is 3-6g / 10min; The EPDM rubber is a terpolymer copolymerized by ethylene, propylene and ENB, wherein the ethylene content is 65-75% and the ENB content is 4-6%; The KN resin has a density of 0.880-0.908 g / cm 3 The polyolefin resin has a melt index of 3-18g / 10min.

2. The 150°C temperature-resistant UV-crosslinked TPE insulating material according to claim 1, characterized in that: The photoinitiator is one or more combinations of benzophenone, triphenylphosphine oxide and benzoin diethyl ether.

3. The 150°C temperature-resistant UV-crosslinked TPE insulating material according to claim 2, characterized in that: The photoinitiator is a mixture of benzophenone and triphenylphosphine oxide in a mass ratio of 3:

1.

4. The 150°C temperature-resistant UV-crosslinked TPE insulating material according to claim 1, characterized in that: The crosslinking agent is one or more combinations of triallyl isocyanurate, trimethylolpropane trimethacrylate, and trimethylolpropane acrylate.

5. The 150°C temperature-resistant UV-crosslinked TPE insulating material according to claim 4, characterized in that: The crosslinking agent is a mixture of triallyl isocyanurate and trimethylolpropane trimethacrylate in a mass ratio of 1:

2.

6. The 150°C temperature-resistant UV-crosslinked TPE insulating material according to claim 1, characterized in that: The antioxidant is one or more combinations of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol, thioethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-mercaptomethylbenzimidazole zinc salt, and tris[2,4-di-tert-butylphenyl]phosphite.

7. The 150°C temperature-resistant UV-crosslinked TPE insulating material according to claim 6, characterized in that: The antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and ethylenedithiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] in a mass ratio of 3:

2.

8. The method for preparing the 150°C temperature-resistant UV-crosslinked TPE insulating material according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, SEBS resin, EPDM rubber, KN resin, photoinitiator, crosslinking agent and antioxidant are mixed, and kneaded at 210° C. for 10-15 minutes to obtain a mixture; S2, extruding and granulating the mixed material in an extruder to obtain the 150° C. temperature-resistant UV-crosslinked TPE insulating material.

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