TPE (thermoplastic elastomer) low-heat-conductivity material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of low-thermal-conductivity materials and refrigeration appliance sealing, in particular to a TPE low-thermal-conductivity material and a preparation method and application thereof. The TPE low-thermal-conductivity material is composed of a base material and a foaming master batch, and the weight ratio of the base material to the foaming master batch is 100: (1.5-4). Wherein the base material comprises an elastomer, white oil, polyolefin resin, a first lubricant, an antibacterial and mildew-proof agent, a first antioxidant and a compatilizer; the foaming master batch comprises POE, modified expanded microspheres, SEBS, white oil, a second lubricant, a second antioxidant, a cross-linking agent and a catalyst. The TPE low-heat-conductivity material has a lower heat conductivity coefficient, and can enable a refrigeration appliance to have a better sealing effect, so that the energy consumption of the refrigeration appliance is effectively reduced, meanwhile, the preparation method of the TPE low-heat-conductivity material is simple and easy to operate, the elasticity of the TPE material is improved, the deformation modulus of the TPE material is effectively improved, and the service life of the TPE material is prolonged. Therefore, the low-heat-conduction material can be widely applied to the field of manufacturing of refrigeration appliances.

Description

Technical Field

[0001] This invention relates to the field of low thermal conductivity materials and sealing technology for refrigeration appliances, specifically to a TPE low thermal conductivity material, its preparation method, and its application. Background Technology

[0002] The thermoplastic elastomer (TPE) used in the sealing strips of traditional refrigeration appliances has a density of 0.92-1.15 g / cm³. 3 Their thermal conductivity is all between 0.24-0.26 W / (m·K). In order to seek a lower thermal conductivity, two types of methods for reducing thermal conductivity have emerged in the market. One type uses chemical foaming agents or physical supercritical foaming to modify the foaming products of these foaming agents. The technology of using foaming agents has problems such as uncontrollable foaming ratio of cells, large particle size after foaming, or cell rupture, which cause cell rupture on the surface of the material. Especially for refrigerator sealing products, the thickness of the air bladder is 0.3-0.6mm. The thickness of the foamed material is thinner than that of traditional foamed materials. The product strength is reduced after foaming, and the uneven surface is unacceptable to customers. The other type uses hollow (glass microsphere silicate type) products to reduce thermal conductivity. During the processing, the breakage rate is high, and the thermal conductivity, density and strength of the material cannot be stably controlled, affecting the uniformity of the product.

[0003] Furthermore, existing TPE foam materials often struggle to balance flexibility and mechanical strength. After foaming, their resistance to compressive deformation decreases, making them prone to permanent deformation and affecting their service life. Simultaneously, traditional materials exhibit poor processability and reprocessability, limiting their application in complex structural components. Summary of the Invention

[0004] To address the problem that existing TPE foam materials struggle to balance flexibility and mechanical strength, and the inability to stably control the thermal conductivity, density, and strength of the resulting thermoplastic elastomers, this invention provides a low thermal conductivity TPE material, its preparation method, and its applications.

[0005] The TPE low thermal conductivity material of the present invention is based on the compound design of modified expanded microspheres and matrix material. Through the innovation of material system and foaming mechanism, the TPE low thermal conductivity material of the present invention has excellent surface quality, stable microbubble structure, good mechanical properties and processing feasibility while having a low thermal conductivity, thereby meeting the increasing demand of refrigeration equipment for efficient heat insulation and comprehensive material performance.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a TPE low thermal conductivity material, wherein the TPE low thermal conductivity material is composed of a base material and a foaming masterbatch, and the weight ratio of the base material to the foaming masterbatch is 100:1.5-4; wherein, The base material includes an elastomer, white oil, polyolefin resin, a first lubricant, an antibacterial and antifungal agent, a first antioxidant, and a compatibilizer; The foaming masterbatch includes POE, modified expanded microspheres, SEBS, white oil, a second lubricant, a second antioxidant, a crosslinking agent, and a catalyst; The modified expandable microspheres are prepared by reacting a modifier with expandable microspheres. The modifier includes EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane and DCP. The mass ratio of EVA, benzyltriethoxysilane, 3-(2,-epoxypropoxy)propyltrimethoxysilane, expanded microspheres and DCP is 45-50:1-2:1-2:9-14:1.

[0007] Preferably, the elastomer is a hydrogenated styrene-butadiene block copolymer and / or a styrene-butadiene block copolymer.

[0008] Preferably, the polyolefin resin is selected from one or more of high-density polyethylene, low-density polyethylene, polypropylene, and POE.

[0009] Preferably, the first lubricant and the second lubricant are each independently selected from one or more of polyethylene wax, paraffin wax, silicone, stearic acid, erucamide and oleamide.

[0010] Preferably, the antibacterial and antifungal agent is selected from one or more of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, zinc pyridinethione and 2-n-octyl-4-isothiazolin-3-one.

[0011] Preferably, the first antioxidant and the second antioxidant are each independently selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 1135 and antioxidant 168.

[0012] Preferably, the compatibilizer is a hydrogenated styrene-butadiene block copolymer grafted with maleic anhydride.

[0013] Preferably, the melting point of the POE is 50-110℃.

[0014] Preferably, the crosslinking agent is trimethylolpropane trimethacrylate.

[0015] Preferably, the catalyst is 1,4-di-tert-butylperoxyisopropylbenzene.

[0016] Preferably, the weight percentages of each component in the base material are as follows: 100 parts of elastomer; 40-140 parts white oil; 10-40 parts of polyolefin resin; 1-6 parts compatibilizer; Antibacterial and antifungal agent: 0.4-1.6 parts; First lubricant: 1-5 parts; First antioxidant 1-4 parts.

[0017] Preferably, the weight percentages of each component in the foaming masterbatch are as follows: 100 copies of POE; 50-100 parts of modified expanded microspheres; SEBS 15-20 copies; 40-140 parts white oil Second lubricant: 0.2-1 part; Second antioxidant 0.2-1 part; 1-2 parts of crosslinking agent; Catalyst 0.5-1 part.

[0018] Preferably, the mass ratio of EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, expanded microspheres and DCP is 45-50:1-2:1-2:9-14:1.

[0019] Secondly, the present invention provides a method for preparing the TPE low thermal conductivity material of the present invention, the preparation method comprising: 1) The elastomer and white oil are mixed and allowed to stand to obtain elastomer A; 2) Elastomer A, polyolefin resin, first lubricant, first antioxidant, antibacterial and antifungal agent and compatibilizer are mixed to prepare mixed powder B; 3) The mixed powder B is fed to a twin-screw extruder for the first extrusion, pelleting, and drying to obtain modified material C; 4) The modified expanded microspheres, the second antioxidant, the second lubricant, POE and SEBS were first mixed in an intensive kneading process. After the mixture was homogeneous, the catalyst and crosslinking agent were added and the mixture was mixed in a second intensive kneading process to obtain foaming masterbatch D. 5) Mix the modified material C with the foaming masterbatch D, and then feed the mixture into a single-screw extruder for the second extrusion.

[0020] Preferably, the elastomer is a hydrogenated styrene-butadiene block copolymer and / or a styrene-butadiene block copolymer.

[0021] Preferably, the polyolefin resin is selected from one or more of high-density polyethylene, low-density polyethylene, polypropylene, and POE.

[0022] Preferably, the first lubricant and the second lubricant are each independently selected from one or more of polyethylene wax, paraffin wax, silicone, stearic acid, erucamide and oleamide.

[0023] Preferably, the antibacterial and antifungal agent is selected from one or more of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, zinc pyridinethione and 2-n-octyl-4-isothiazolin-3-one.

[0024] Preferably, the first antioxidant and the second antioxidant are each independently selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 1135 and antioxidant 168.

[0025] Preferably, the compatibilizer is a hydrogenated styrene-butadiene block copolymer grafted with maleic anhydride.

[0026] Preferably, the melting point of the POE is 50-110℃; The crosslinking agent is trimethylolpropane trimethacrylate; The catalyst is 1,4-di-tert-butylperoxyisopropylbenzene.

[0027] Preferably, in step 2), the weight percentages of each component in the mixed powder B are as follows: 100 parts of elastomer; 40-140 parts white oil; 10-40 parts of polyolefin resin; 1-6 parts compatibilizer; Antibacterial and antifungal agent: 0.4-1.6 parts; First lubricant: 1-5 parts; First antioxidant 1-4 parts.

[0028] Preferably, in step 4), the weight percentages of each component in the foaming masterbatch D are as follows: 100 copies of POE; 50-100 parts of modified expanded microspheres; SEBS 15-20 copies; 40-140 parts white oil; Second lubricant: 0.2-1 part; Second antioxidant 0.2-1 part; 1-2 parts of crosslinking agent; Catalyst 0.5-1 part.

[0029] Preferably, in step 5), the weight ratio of the modified material C to the foaming masterbatch D is 100:1.5-4.

[0030] Preferably, the modified expandable microspheres are prepared by a modifier and expandable microspheres, wherein the modifier includes EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane and DCP.

[0031] Preferably, in step 1), the blending conditions include: in a horizontal mixing pot, for 5-15 minutes.

[0032] Preferably, in step 1), the settling time is 10-14 hours.

[0033] Preferably, in step 2), the mixing conditions include: in a high-speed mixing pot, the stirring speed is 500-600 rpm and the time is 3-8 min.

[0034] Preferably, in step 3), the temperature of the first extrusion is 140-200°C.

[0035] Preferably, in step 3), the pelleting is carried out underwater.

[0036] Preferably, in step 4), the conditions for the first internal mixing include: in the internal mixer, the rotation speed is 70-100 rpm, the temperature is 120-130℃, until the torque is stable, and then continue mixing for 2-5 minutes.

[0037] Preferably, in step 4), the conditions for the second internal mixing include: a rotation speed of 70-100 rpm, a temperature of 120-130°C, until the torque stabilizes, and then continuing internal mixing for 3-6 minutes.

[0038] Preferably, in step 5), the temperature of the second extrusion is 120-180°C.

[0039] Preferably, the preparation method of the modified expanded microspheres includes: EVA, benzyltriethoxysilane and 3-(2,3-epoxypropoxy)propyltrimethoxysilane are mixed in a mixer at a temperature of 80-90°C and a speed of 30-50 rpm, the temperature is raised to 110-120°C and expanded microspheres and DCP are added, the temperature is further raised to 120-125°C and the material is discharged and crushed to obtain modified expanded microspheres.

[0040] Preferably, the mass ratio of EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, expanded microspheres and DCP is 45-50:1-2:1-2:9-14:1.

[0041] Thirdly, the present invention provides an application of the TPE low thermal conductivity material described herein in sealing materials for refrigeration appliances.

[0042] Beneficial effects: (1) The TPE low thermal conductivity material of the present invention uses modified expandable microspheres to replace traditional glass microspheres, chemical foaming and physical supercritical foaming methods. The special polymer material is used to wrap the heated and vaporized gas and expand the polymer material to 10 times to form a special closed-cell hollow structure. The polymer hollow microspheres replace other fillers and are uniformly dispersed in the material. Due to the presence of the closed-cell hollow spheres, the heat conduction path is blocked and the heat transfer is delayed, thereby achieving the effect of reducing the thermal conductivity and effectively reducing the energy consumption of the refrigeration appliance.

[0043] (2) The present invention significantly alters the structure and foaming quality of the foaming masterbatch. The POE / SEBS / modified expanded microsphere ternary blend system forms a "sea-island" structure after dynamic vulcanization. POE is the continuous phase, while SEBS is the dispersed phase. The modified expanded microspheres contain EVA grafted with siloxane, which improves the compatibility between the two. This structure greatly improves the melt strength, enabling the melt to effectively encapsulate the gas when the expanded microspheres expand, avoiding cell merging and collapse, which is beneficial for obtaining small and dense expanded microspheres. Secondly, the greater melt strength allows the cell walls to withstand greater tensile force without breaking, thus achieving a higher expansion ratio and obtaining a lower density material, which also results in a lower defect rate in the cells.

[0044] (3) This invention achieves a combination of softness and high strength through cross-linking, resulting in a product that is both soft and comfortable, with excellent resilience and durability, and excellent resistance to permanent compression deformation, making it less prone to being flattened during use. Since the foaming masterbatch is dynamically vulcanized through POE / SEBS / modified expanded microspheres, it has good thermoplastic processability and a certain degree of reprocessability.

[0045] (4) The modified expanded microspheres use EVA as a carrier to adjust the softness and polarity of the POE / SEBS / EVA system in the TPE low thermal conductivity material of the present invention, so that the product can adapt to different application scenarios. Due to the presence of EVA component in the modified expanded microspheres, POE / SEBS / expansion masterbatch can be combined to achieve softness and high strength. As an excellent foaming substrate, EVA can better encapsulate the expanded microspheres by combining with the expanded microspheres to achieve the purpose of small and dense pores. Detailed Implementation

[0046] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0047] In a first aspect, the present invention provides a TPE low thermal conductivity material, wherein the TPE low thermal conductivity material is composed of a base material and a foaming masterbatch, and the weight ratio of the base material to the foaming masterbatch is 100:1.5-4; wherein, The base material includes an elastomer, white oil, polyolefin resin, a first lubricant, an antibacterial and antifungal agent, a first antioxidant, and a compatibilizer; The foaming masterbatch includes POE, modified expanded microspheres, SEBS, white oil, a second lubricant, a second antioxidant, a crosslinking agent, and a catalyst; The modified expandable microspheres are prepared by using a modifier and expandable microspheres. The modifier includes EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, and DCP.

[0048] The mass ratio of EVA, benzyltriethoxysilane, 3-(2,-epoxypropoxy)propyltrimethoxysilane, expanded microspheres and DCP is 45-50:1-2:1-2:9-14:1.

[0049] This invention significantly alters the structure and foaming quality of the foaming masterbatch. The POE / SEBS / EVA ternary blend system forms a "sea-island" structure after dynamic vulcanization. This structure greatly improves melt strength, allowing the melt to effectively encapsulate the expanded microspheres during expansion, preventing microsphere coalescence and rupture, and facilitating a small and dense distribution of expanded microspheres. Secondly, the higher melt strength allows the pore walls to withstand greater tensile forces without rupture, thus achieving a higher expansion ratio, resulting in a lower density material, and also giving the expanded microspheres a lower defect rate. In a preferred embodiment of this invention, the elastomer is a hydrogenated styrene-butadiene block copolymer and / or a styrene-butadiene block copolymer.

[0050] Meanwhile, due to the presence of POE and SEBS in the system, it possesses extremely high impact toughness and flexibility. Through cross-linking, it achieves a combination of softness and high strength, resulting in a product that is both soft and comfortable, with excellent resilience and durability, and excellent resistance to permanent compression deformation, making the product less prone to flattening during use. Since the foaming masterbatch is achieved through dynamic vulcanization of POE / SEBS / modified expanded microspheres, it exhibits good thermoplastic processability and a certain degree of reprocessability.

[0051] Using EVA as a carrier, the modified expanded microspheres can adjust the softness and polarity of the POE / SEBS / modified expanded microsphere system in the TPE low thermal conductivity material of this invention, enabling the product to adapt to different application scenarios. Due to the presence of the EVA component in the modified expanded microspheres, the POE / SEBS / modified expanded microspheres can be combined to achieve softness and high strength. As an excellent foaming substrate, EVA, by combining with the expanded microspheres to form modified expanded microspheres, can better encapsulate the expanded microspheres and achieve the purpose of small and dense pores.

[0052] In a preferred embodiment of the present invention, the elastomer is a hydrogenated styrene-butadiene block copolymer and / or a styrene-butadiene block copolymer.

[0053] In a preferred embodiment of the present invention, the polyolefin resin is selected from one or more of high-density polyethylene, low-density polyethylene, polypropylene, and POE.

[0054] In a preferred embodiment of the present invention, the first lubricant and the second lubricant are each independently selected from one or more of polyethylene wax, paraffin wax, silicone, stearic acid, erucamide and oleamide.

[0055] In a preferred embodiment of the present invention, the antibacterial and antifungal agent is selected from one or more of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, zinc pyridinethione and 2-n-octyl-4-isothiazolin-3-one.

[0056] In a preferred embodiment of the present invention, the first antioxidant and the second antioxidant are each independently selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 1135 and antioxidant 168.

[0057] In a preferred embodiment of the present invention, the compatibilizer is a hydrogenated styrene-butadiene block copolymer grafted with maleic anhydride.

[0058] In a preferred embodiment of the present invention, the melting point of the POE is 50-110°C.

[0059] In a preferred embodiment of the present invention, the crosslinking agent is trimethylolpropane trimethacrylate.

[0060] In a preferred embodiment of the present invention, the catalyst is 1,4-di-tert-butylperoxyisopropylbenzene.

[0061] In a preferred embodiment of the present invention, the weight percentages of each component in the base material are as follows: 100 parts of elastomer; 40-140 parts white oil; 10-40 parts of polyolefin resin; 1-6 parts compatibilizer; Antibacterial and antifungal agent: 0.4-1.6 parts; First lubricant: 1-5 parts; First antioxidant 1-4 parts.

[0062] In a preferred embodiment of the present invention, the weight percentages of each component in the foaming masterbatch are as follows: 100 copies of POE; 50-100 parts of modified expanded microspheres; SEBS 15-20 copies; 40-140 parts white oil Second lubricant: 0.2-1 part; Second antioxidant 0.2-1 part; 1-2 parts of crosslinking agent; Catalyst 0.5-1 part.

[0063] In a preferred embodiment of the present invention, the mass ratio of EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, expanded microspheres and DCP is 45-50:1-2:1-2:9-14:1.

[0064] Secondly, the present invention provides a method for preparing the TPE low thermal conductivity material of the present invention, the preparation method comprising: 1) The elastomer and white oil are mixed and allowed to stand to obtain elastomer A; 2) Elastomer A, polyolefin resin, first lubricant, first antioxidant, antibacterial and antifungal agent and compatibilizer are mixed to prepare mixed powder B; 3) The mixed powder B is fed to a twin-screw extruder for the first extrusion, pelleting, and drying to obtain modified material C; 4) The modified expanded microspheres, the second antioxidant, the second lubricant, POE and SEBS were first mixed in an intensive kneading process. After the mixture was homogeneous, the catalyst and crosslinking agent were added and the mixture was mixed in a second intensive kneading process to obtain foaming masterbatch D. 5) Mix the modified material C with the foaming masterbatch D, and then feed the mixture into a single-screw extruder for the second extrusion.

[0065] In a preferred embodiment of the present invention, the elastomer is a hydrogenated styrene-butadiene block copolymer and / or a styrene-butadiene block copolymer.

[0066] In a preferred embodiment of the present invention, the polyolefin resin is selected from one or more of high-density polyethylene, low-density polyethylene, polypropylene, and POE.

[0067] In a preferred embodiment of the present invention, the first lubricant and the second lubricant are each independently selected from one or more of polyethylene wax, paraffin wax, silicone, stearic acid, erucamide and oleamide.

[0068] In a preferred embodiment of the present invention, the antibacterial and antifungal agent is selected from one or more of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, zinc pyridinethione and 2-n-octyl-4-isothiazolin-3-one.

[0069] In a preferred embodiment of the present invention, the first antioxidant and the second antioxidant are each independently selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 1135 and antioxidant 168.

[0070] In a preferred embodiment of the present invention, the compatibilizer is a hydrogenated styrene-butadiene block copolymer grafted with maleic anhydride.

[0071] In a preferred embodiment of the present invention, the melting point of the POE is 50-110°C; The crosslinking agent is trimethylolpropane trimethacrylate; The catalyst is 1,4-di-tert-butylperoxyisopropylbenzene.

[0072] In a preferred embodiment of the present invention, in step 2), the weight percentages of each component in the mixed powder B are as follows: 100 parts of elastomer; 40-140 parts white oil; 10-40 parts of polyolefin resin; 1-6 parts compatibilizer; Antibacterial and antifungal agent: 0.4-1.6 parts; First lubricant: 1-5 parts; First antioxidant 1-4 parts.

[0073] In a preferred embodiment of the present invention, in step 4), the weight percentages of each component in the foaming masterbatch D are as follows: 100 copies of POE; 50-100 parts of modified expanded microspheres; SEBS 15-20 copies; 40-140 parts white oil; Second lubricant: 0.2-1 part; Second antioxidant 0.2-1 part; 1-2 parts of crosslinking agent; Catalyst 0.5-1 part.

[0074] In a preferred embodiment of the present invention, in step 5), the weight ratio of the modified material C to the foaming masterbatch D is 100:1.5-4.

[0075] In a preferred embodiment of the present invention, the modified expandable microspheres are prepared by a modifier and expandable microspheres, wherein the modifier includes EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane and DCP.

[0076] In a preferred embodiment of the present invention, in step 1), the blending conditions include: in a horizontal mixing pot, for 5-15 minutes.

[0077] In a preferred embodiment of the present invention, in step 1), the settling time is 10-14 hours.

[0078] In a preferred embodiment of the present invention, in step 2), the mixing conditions include: in a high-speed mixing pot, the stirring rate is 500-600 rpm and the time is 3-8 min.

[0079] In a preferred embodiment of the present invention, in step 3), the temperature of the first extrusion is 140-200°C.

[0080] In a preferred embodiment of the present invention, in step 3), the pelleting is carried out underwater.

[0081] In a preferred embodiment of the present invention, in step 4), the conditions for the first internal mixing include: in the internal mixer, the rotation speed is 70-100 rpm, the temperature is 120-130℃, until the torque is stable, and then continue internal mixing for 2-5 minutes.

[0082] In a preferred embodiment of the present invention, in step 4), the conditions for the second internal mixing include: a rotation speed of 70-100 rpm, a temperature of 120-130°C, until the torque stabilizes, and then continuing internal mixing for 3-6 minutes.

[0083] In a preferred embodiment of the present invention, in step 5), the temperature of the second extrusion is 120-180°C.

[0084] In a preferred embodiment of the present invention, the method for preparing the modified expanded microspheres includes: mixing EVA, benzyltriethoxysilane and 3-(2,3-epoxypropoxy)propyltrimethoxysilane in a mixer at a temperature of 80-90°C and a speed of 30-50 rpm; adding expanded microspheres and DCP at a temperature of 110-120°C; continuing to raise the temperature to 120-125°C to discharge the material; crushing the material to obtain the modified expanded microspheres.

[0085] In a preferred embodiment of the present invention, the mass ratio of EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, expanded microspheres and DCP is 45-50:1-2:1-2:9-14:1.

[0086] Thirdly, the present invention provides an application of the TPE low thermal conductivity material described herein in sealing materials for refrigeration appliances.

[0087] The present invention will be described in detail below through embodiments. Unless otherwise specified, the experimental methods and equipment described in the following embodiments are conventional methods and equipment.

[0088] Preparation Example 1 The method for preparing modified expanded microspheres is as follows: 45 parts of EVA, 1 part of benzyltriethoxysilane and 1 part of 3-(2,3-epoxypropoxy)propyltrimethoxysilane were mixed in a mixer at 85°C and 40 rpm. When the mixer temperature reached 115°C, expanded microspheres and DCP were added. The mixture was heated and stirred until the mixer temperature reached 120°C and the material was discharged. The material was then crushed to obtain modified expanded microspheres.

[0089] Example 1 (1) Preparation of TPE low thermal conductivity material base: Take 50 parts of hydrogenated styrene-butadiene block copolymer, 50 parts of styrene-butadiene block copolymer and 100 parts of white oil and add them to a horizontal mixing pot and mix for 10 min. After standing for 12 h, a uniform oil-filled elastomer A is obtained. (2) The elastomer A obtained in step (1) and 20 parts of high-density polyethylene, 3 parts of stearic acid, 2 parts of antioxidant 1010, 1.0 part of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one and 3 parts of hydrogenated styrene-butadiene block copolymer grafted maleic anhydride are added to a high-speed mixing pot and mixed at low speed for 5 minutes to obtain a dry and uniform mixed powder B. (3) The dry and uniform mixed powder B obtained in step (2) is fed to an open twin-screw extruder and extruded. The extrusion processing temperature is controlled within the range of 180°C. The powder is then granulated underwater and dried to obtain modified material C for later use. (4) 80 parts of the modified expanded microspheres prepared in Preparation Example 1, 0.8 parts of antioxidant 1010 and 0.5 parts of stearic acid were placed in a mixer and mixed at a temperature of 125°C and a speed of 80 rpm. After the torque stabilized for 2 minutes, 100 parts of POE and 15 parts of SEBS were added. After the torque stabilized again for 2 minutes, 0.2 parts of stearic acid, 1 part of 1,4-di-tert-butylperoxyisopropylbenzene and 1 part of trimethylolpropane trimethacrylate were added. After mixing for 4 minutes, the mixer was stopped, the material was taken out and transported to an open twin-screw extruder. The molding temperature was 80°C and the material was dried underwater to obtain foaming masterbatch D. (5) Take 100 parts of the modified granules C obtained in step (3) and 3 parts of foaming masterbatch D, mix them evenly to obtain CD, and finally send the mixture CD into a single screw extruder at a temperature of 160℃ to obtain a low-conductivity hot-sealing sleeve, which is denoted as B1.

[0090] Example 2 (1) Preparation of TPE low thermal conductivity material base: Take 100 parts of styrene-butadiene block copolymer and 120 parts of white oil and add them to a horizontal mixing pot and mix for 10 min. After standing for 12 h, a uniform oil-filled elastomer A is obtained. (2) The elastomer A obtained in step (1) and 20 parts of high-density polyethylene, 3 parts of stearic acid, 2 parts of antioxidant 1010, 1.0 part of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one and 3 parts of hydrogenated styrene-butadiene block copolymer grafted maleic anhydride are added to a high-speed mixing pot and mixed at low speed for 5 minutes to obtain a dry and uniform mixed powder B. (3) The dry and uniform mixed powder B obtained in step (2) is fed to an open twin-screw extruder and extruded. The extrusion processing temperature is controlled within the range of 180°C. The powder is then granulated underwater and dried to obtain modified material C for later use. (4) 100 parts of the modified expanded microspheres prepared in Preparation Example 1, 0.8 parts of antioxidant 1010 and 0.5 parts of stearic acid were placed in a mixer and mixed at a temperature of 125°C and a speed of 80 rpm. After the torque stabilized for 2 minutes, 100 parts of POE and 15 parts of SEBS were added. After the torque stabilized again for 2 minutes, 0.2 parts of stearic acid, 1 part of 1,4-di-tert-butylperoxyisopropylbenzene and 1 part of trimethylolpropane trimethacrylate were added. After mixing for 4 minutes, the mixer was stopped, the material was taken out and transported to an open twin-screw extruder. The molding temperature was 80°C and the material was dried underwater to obtain foaming masterbatch D. (5) Take 100 parts of the modified granules C obtained in step (3) and 3 parts of foaming masterbatch D, mix them evenly to obtain CD, and finally send the mixture CD into a single screw extruder at a temperature of 160℃ to obtain a low-conductivity hot-sealing sleeve, which is denoted as B2.

[0091] Example 3 (1) Preparation of TPE low thermal conductivity material base: Take 100 parts of hydrogenated styrene-butadiene block copolymer and 40 parts of white oil and add them to a horizontal mixing pot and mix for 10 min. After standing for 12 h, a uniform oil-filled elastomer A is obtained. (2) The elastomer A obtained in step (1) and 20 parts of high-density polyethylene, 3 parts of stearic acid, 2 parts of antioxidant 1010, 1.0 part of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one and 3 parts of hydrogenated styrene-butadiene block copolymer grafted maleic anhydride are added to a high-speed mixing pot and mixed at low speed for 5 minutes to obtain a dry and uniform mixed powder B. (3) The dry and uniform mixed powder B obtained in step (2) is fed to an open twin-screw extruder and extruded. The extrusion processing temperature is controlled within the range of 180°C. The powder is then granulated underwater and dried to obtain modified material C for later use. (4) 50 parts of the modified expanded microspheres prepared in Preparation Example 1, 0.8 parts of antioxidant 1010 and 0.5 parts of stearic acid were placed in a mixer and mixed at a temperature of 125°C and a speed of 80 rpm. After the torque stabilized for 2 minutes, 100 parts of POE and 15 parts of SEBS were added. After the torque stabilized again for 2 minutes, 0.2 parts of stearic acid, 1 part of 1,4-di-tert-butylperoxyisopropylbenzene and 1 part of trimethylolpropane trimethacrylate were added. After mixing for 4 minutes, the mixer was stopped, the material was taken out and transported to an open twin-screw extruder. The molding temperature was 80°C, and the material was dried underwater to obtain foaming masterbatch D. (5) Take 100 parts of the modified granules C obtained in step (3) and 3 parts of foaming masterbatch D, mix them evenly to obtain CD, and finally send the mixture CD into a single screw extruder at a temperature of 160℃ to obtain a low-conductivity hot-sealing sleeve, which is denoted as B3.

[0092] Comparative Example 1 The method of Example 1 was implemented, except that the modified expanded microspheres in step (4) were not added, and other conditions remained unchanged, and a door seal sleeve was obtained, which was denoted as D1.

[0093] Test Example 1 The performance of the TPE low-conductivity door seal prepared in Example 1 and the traditional TPE door seal were tested. The test items, test standards and test results are shown in Table 1.

[0094] Table 1

[0095] As shown in Table 1, the TPE low thermal conductivity material door seal of the present invention has a 45% lower thermal conductivity than the traditional TPE door seal, reduces refrigerator energy consumption by 3-4%, has a better tensile modulus of 50%, and a lower compression set. This proves that the TPE low thermal conductivity material has a smaller average particle size and higher cell density, and has significant advantages in low thermal conductivity and mechanical properties.

[0096] In summary, this invention solves the technical pain points of existing TPE foaming materials by synergistic design of modified expanded microspheres and base materials, combined with a specific preparation process. The provided TPE low thermal conductivity material can be widely used in the field of refrigeration appliance sealing and has good industrialization prospects.

[0097] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A TPE low thermal conductivity material, characterized in that, The TPE low thermal conductivity material is composed of a base material and foaming masterbatch, wherein the weight ratio of the base material to the foaming masterbatch is 100:1.5-4; wherein, The base material includes an elastomer, white oil, polyolefin resin, a first lubricant, an antibacterial and antifungal agent, a first antioxidant, and a compatibilizer; The foaming masterbatch includes POE, modified expanded microspheres, SEBS, white oil, a second lubricant, a second antioxidant, a crosslinking agent, and a catalyst; The modified expandable microspheres are prepared by reacting a modifier with expandable microspheres. The modifier includes EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane and DCP. The mass ratio of EVA, benzyltriethoxysilane, 3-(2,-epoxypropoxy)propyltrimethoxysilane, expanded microspheres and DCP is 45-50:1-2:1-2:9-14:

1.

2. The TPE low thermal conductivity material according to claim 1, characterized in that, The elastomer is a hydrogenated styrene-butadiene block copolymer and / or a styrene-butadiene block copolymer; The polyolefin resin is selected from one or more of high-density polyethylene, low-density polyethylene, polypropylene, and POE; The first lubricant and the second lubricant are each independently selected from one or more of polyethylene wax, paraffin wax, silicone, stearic acid, erucamide and oleamide; The antibacterial and antifungal agent is selected from one or more of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, zinc pyridinethione and 2-n-octyl-4-isothiazolin-3-one; The first antioxidant and the second antioxidant are each independently selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 1135 and antioxidant 168; The compatibilizer is a hydrogenated styrene-butadiene block copolymer grafted with maleic anhydride. The melting point of the POE is 50-110℃; The crosslinking agent is trimethylolpropane trimethacrylate; The catalyst is 1,4-di-tert-butylperoxyisopropylbenzene.

3. The TPE low thermal conductivity material according to claim 1 or 2, characterized in that, The weight percentages of each component in the base material are as follows: 100 parts of elastomer; 40-140 parts white oil; 10-40 parts of polyolefin resin; 1-6 parts compatibilizer; Antibacterial and antifungal agent: 0.4-1.6 parts; First lubricant: 1-5 parts; First antioxidant 1-4 parts; The weight percentages of each component in the foaming masterbatch are as follows: 100 copies of POE; 50-100 parts of modified expanded microspheres; SEBS 15-20 copies; 40-140 parts white oil Second lubricant: 0.2-1 part; Second antioxidant 0.2-1 part; 1-2 parts of crosslinking agent; Catalyst 0.5-1 part; The mass ratio of EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, expanded microspheres and DCP is 45-50:1-2:1-2:9-14:

1.

4. A method for preparing a TPE low thermal conductivity material as described in any one of claims 1-3, characterized in that, The preparation method includes: 1) The elastomer and white oil are mixed and allowed to stand to obtain elastomer A; 2) Elastomer A, polyolefin resin, first lubricant, first antioxidant, antibacterial and antifungal agent and compatibilizer are mixed to prepare mixed powder B; 3) The mixed powder B is fed to a twin-screw extruder for the first extrusion, pelleting, and drying to obtain modified material C; 4) The modified expanded microspheres, the second antioxidant, the second lubricant, POE and SEBS were subjected to a first internal mixing, and then a catalyst and a crosslinking agent were added for a second internal mixing to obtain foaming masterbatch D; 5) Mix the modified material C with the foaming masterbatch D, and feed the mixture to a single-screw extruder for the second extrusion.

5. The preparation method according to claim 4, characterized in that, The elastomer is a hydrogenated styrene-butadiene block copolymer and / or a styrene-butadiene block copolymer; The polyolefin resin is selected from one or more of high-density polyethylene, low-density polyethylene, polypropylene, and POE; The first lubricant and the second lubricant are each independently selected from one or more of polyethylene wax, paraffin wax, silicone, stearic acid, erucamide and oleamide; The antibacterial and antifungal agent is selected from one or more of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, zinc pyridinethione and 2-n-octyl-4-isothiazolin-3-one; The first antioxidant and the second antioxidant are each independently selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 1135 and antioxidant 168; The compatibilizer is a hydrogenated styrene-butadiene block copolymer grafted with maleic anhydride. The melting point of the POE is 50-110℃; The crosslinking agent is trimethylolpropane trimethacrylate; The catalyst is 1,4-di-tert-butylperoxyisopropylbenzene.

6. The preparation method according to claim 4 or 5, characterized in that, In step 2), the weight percentages of each component in the mixed powder B are as follows: 100 parts of elastomer; 40-140 parts white oil; 10-40 parts of polyolefin resin; 1-6 parts compatibilizer; Antibacterial and antifungal agent: 0.4-1.6 parts; First lubricant: 1-5 parts; First antioxidant 1-4 parts; In step 4), the weight percentages of each component in the foaming masterbatch D are as follows: 100 copies of POE; 50-100 parts of modified expanded microspheres; SEBS 15-20 copies; 40-140 parts white oil; Second lubricant: 0.2-1 part; Second antioxidant 0.2-1 part; 1-2 parts of crosslinking agent; Catalyst 0.5-1 part; Preferably, in step 5), the weight ratio of the modified material C to the foaming masterbatch D is 100:1.5-4.

7. The preparation method according to any one of claims 4-6, characterized in that, The modified expandable microspheres are prepared by using a modifier and expandable microspheres. The modifier includes EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, and DCP.

8. The preparation method according to any one of claims 4-7, characterized in that, In step 1), the blending conditions include: in a horizontal mixing pot, for 5-15 minutes; In step 1), the settling time is 10-14 hours; In step 2), the mixing conditions include: in a high-speed mixing pot, the stirring speed is 500-600 rpm and the time is 3-8 min; In step 3), the temperature of the first extrusion is 140-200℃; In step 3), the pelleting is carried out underwater; In step 4), the conditions for the first internal mixing include: in the internal mixer, the speed is 70-100 rpm and the temperature is 120-130℃, until the torque is stable, and then continue mixing for 2-5 minutes. In step 4), the conditions for the second internal mixing include: a rotation speed of 70-100 rpm, a temperature of 120-130℃, until the torque stabilizes, and then continue mixing for 3-6 minutes. In step 5), the temperature of the second extrusion is 120-180°C.

9. The preparation method according to any one of claims 4-8, characterized in that, The method for preparing the modified expanded microspheres includes: EVA, benzyltriethoxysilane and 3-(2,3-epoxypropoxy)propyltrimethoxysilane are mixed in a mixer at a temperature of 80-90℃ and a speed of 30-50 rpm, the temperature is raised to 110-120℃ and expanded microspheres and DCP are added, the temperature is further raised to 120-125℃ and the material is discharged and crushed to obtain the modified expanded microspheres; The mass ratio of EVA, benzyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, expanded microspheres and DCP is 45-50:1-2:1-2:9-14:

1.

10. The use of the TPE low thermal conductivity material according to any one of claims 1-3 in the preparation of sealing materials for refrigeration appliances.

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