PVC and TPEE blending modified alloy and refrigerator sealing strip containing alloy

Abstract

The invention discloses a PVC (polyvinyl chloride) SG3-TPEE (thermoplastic elastomer) composite material which comprises the following components in parts by mass: PVC SG3, a TPEE prefabricated mixture, a stabilizer, DOTP (dioctyl terephthalate), coarse whiting, a processing aid, an antioxidant 626 and a lubricant. The TPEE prefabricated mixture comprises the following components in parts by weight: 70-80 parts of ATPEE with the shore hardness of 80, 2-5 parts of a viscosity reducer, 20-30 parts of talcum powder with the particle size of 2000-3000 meshes, 1-3 parts of macrogol ester and 1-2 parts of polyethylene wax with the average molecular weight of 2000-5000. The low-temperature brittleness temperature range of the refrigerator sealing strip is-45 DEG C to-48 DEG C, the low-temperature hardness change rate is smaller than 10%, the tensile strength is larger than or equal to 15 mpa, the elongation at break is larger than or equal to 300%, and the migration resistance is excellent.

Description

Technical Field

[0001] The invention relates to the field of alloys, and in particular to a PVC and TPEE blended modified refrigerator door seal alloy. Background Art

[0002] The door seal is an extremely important part of the refrigerator. It is not only an appearance part, but also a structural part and a performance part. The performance of the door seal directly affects the use of the refrigerator, and the door seal material plays a vital role in the performance of this part. As the main sealing part of the refrigerator, the door seal should, on the one hand, have a better sealing effect on the refrigerator and reduce the heat exchange between the air in the box and the outside world; on the other hand, it should reduce the heat conduction effect of the material itself, which is also conducive to reducing heat exchange.

[0003] At present, the commonly used refrigerator sealing strip material is PVC. Due to the excellent performance, low price and sufficient market supply of PVC, soft PVC materials are still the main sealing materials in refrigerators, freezers, thermostats, and residential doors and windows. PVC sealing strips are not only low in cost and easy to process, but also have the appearance properties similar to rubber after adding modifiers. They have rubber-like surface smoothness, softness and resilience, so they have been widely used.

[0004] However, the current PVC sealing strips still have many defects in use, such as poor resilience and insufficient low-temperature resistance, which affect the use and quality of refrigerators and increase electricity consumption. Therefore, there is still room for further improvement. Summary of the invention

[0005] In a first aspect, the present application provides a PVC and TPEE blended modified alloy, comprising the following components in parts by weight: PVC SG3 40-60 parts TPEE prefabricated mixture 15-20 parts Stabilizer 6-10 parts DOTP 32-35 copies 15-25 parts of heavy calcium 1-3 parts of processing aid Antioxidant 626 0.05-0.3 parts Lubricant 0.05-0.3 parts Preferably, the TPEE prefabricated mixture is composed of the following components in parts by weight: Shore hardness 80A TPEE 70-80 parts 2-5 parts of viscosity reducer 20-30 parts of talcum powder with mesh size of 2000-3000 Polyethylene glycol ester 1-3 parts 1-2 parts of polyethylene wax with an average molecular weight of 2000-5000 Since TPEE has excellent low temperature resistance (-70℃), no brittleness, low temperature flexibility, resilience and mechanical properties, the original intention of the experiment was to combine PVC and TPEE to overcome the defects of PVC.

[0006] In order to better combine the two resins, according to multiple system rheology theories, the viscosity of the suspension system composed of resin particles is generally determined by the free amount and the interaction force between the resin particles. The simple dispersion system composed of PVC and TPEE makes the wetting process easier and faster through the wetting of resin particles by DOTP and epoxidized soybean oil. When the resin particles are wetted, under the action of shear force, diffusion force and van der Waals force, DOTP small molecules begin to penetrate into the pores of the resin particles. In fact, this is also the beginning of solvation. After such continuous solvation, the penetration of DOTP small molecules into the pores causes the resin particles to swell, the secondary particles to disintegrate, the small molecules and the chain segments to interact, and the small molecules drill into the molecular chains of PVC and TPEE. In theory, it can be done, but in practice, it is found that if TPEE and PVC are directly fused through other additives, it will be found that the interface of TPEE and PVC is difficult to penetrate each other, resulting in DOTP and epoxidized soybean oil can only penetrate in the PVC system, and it is difficult to play well in TPEE, and it is also difficult to fuse the two to form an alloy.

[0007] After continuous practice and research by the inventors, the viscosity reducer of the present application (cis-13-docoselenamide, cis-9-octadeceneamide and stearyl stearate are compounded in a mass ratio of 1: (0.8-1.5): (0.2-0.6)) is combined with 2000-3000 mesh talcum powder, polyethylene glycol ester and polyethylene wax with an average molecular weight of 2000-5000 to make TPEE into a premix. First, TPEE is added with talcum powder and lubricant to reduce the melt viscosity of TPEE, providing good processing conditions for blending PVC and TPEE. At the same time, it has a strong affinity for inorganic fillers, so that it can be fully activated and modified, destroying and preventing the agglomeration of inorganic matter, so that it is more evenly dispersed in the polymer, so that the amount of filler added can be increased, and at the same time, relying on strong interfacial bonding, the effect of toughening and strengthening can be achieved. It can improve the compatibility of the components of the system, promote plasticization, reduce melt viscosity, improve processing fluidity, reduce the torque of processing equipment, reduce processing energy consumption, and improve production efficiency.

[0008] The structure of the viscosity reducer greatly reduces the surface free energy of the interface between PVC and TPEE resin particles in the plastisol system. The shielding effect reduces the electrostatic force between resin particles, and the covering effect reduces the friction coefficient of collision and sliding between resin particles. The multi-functional structure with highly active anchoring groups modifies the surface of filler particles through multi-point adsorption of the "anchor" group and chemical reactions at the same time, achieving complete surface chemical reaction coating, making the filler surface organic, thereby effectively reducing the surface energy of the filler and preventing the agglomeration of fillers. In addition, the long polymer chain in the product macromolecule has a strong affinity and compatibility with the matrix polymer material, which greatly improves the processing performance of the composite material system without affecting the physical properties.

[0009] The premix is ​​processed with PVC and other additives to better integrate PVC and TPEE to form a PVC-TPEE alloy with excellent low-temperature resistance, low-temperature flexibility and resilience. The refrigerator sealing strip made of this alloy makes the refrigerator have good sealing performance and less electricity consumption, thereby obtaining an environmentally friendly refrigerator sealing strip alloy.

[0010] Preferably, the lubricant is compounded by aluminum stearate and glycerol random polyether in a mass ratio of 1:(1.5-3.6).

[0011] The above-mentioned solvation process is accelerated with the increase of temperature and the application of shear force. As the solvation proceeds, the amount of free plasticizer in the system continues to decrease and the viscosity continues to increase. If the processing time is relatively long when processing thick refrigerator sealing strips, the solvation process will be prolonged. At this time, the viscosity of the system will increase and affect the molding uniformity of the finished alloy product. The lubricant compounded by aluminum stearate and propylene glycol random polyether in a mass ratio of 1: (1.5-3.6) in this application can more fully reduce the system viscosity of PVC-TPEE, so that TPEE can always better blend with PVC during the processing process to form a PVC-TPEE alloy with a uniform texture, so as to use refrigerator sealing strips of various thicknesses.

[0012] Preferably, the preparation method of the TPEE prefabricated mixture is: TPEE is mixed with talc, polyethylene glycol ester and polyethylene wax and then granulated, wherein the granulation temperature is 120-130°C in the first zone of the feed port, 130-140°C in the second zone, 145-150°C in the third zone, 150-155°C in the fourth zone and 150-155°C in the die zone, resulting in particles that are TPEE prefabricated mixtures.

[0013] Preferably, the stabilizer is a Ca / Zn composite and 3-5 parts of epoxidized soybean oil.

[0014] The combination of epoxidized soybean oil and Ca / Zn stabilizer system has a high synergistic effect. The HCL produced by degradation is absorbed by the epoxy group and metal soap salt, the HCL concentration is reduced, and the HCL removal rate of PVC is reduced, thereby improving the stability of PVC.

[0015] Preferably, the processing aid is 0.5-1.5 parts of 1,2-benzenedisulfonyl azide and 0.5-1.5 parts of tricresyl phosphate.

[0016] The use of macromolecular plasticizers can significantly improve the tensile strength, elongation at break and other mechanical properties of the door seal material, and extend the service life of the material. Considering the complexity of the refrigerator during use, the use of polyester plasticizers and epoxy soybean oil can improve the weather resistance and chemical resistance of the product. However, macromolecular plasticizers become brittle at low temperatures, so the plasticizer of this application also has small molecule DOTP to enhance the low temperature resistance of the alloy.

[0017] In the actual research and development process, it was found that no matter how the ratio and type of macromolecular plasticizers and small molecule plasticizers are adjusted, the migration of sealing strips will inevitably occur. Specifically, the refrigerator sealing strips will stick to the refrigerator, affecting the use and quality of the refrigerator, and will also increase electricity consumption. The migration phenomenon is mainly caused by the chemical reaction between the small molecule plasticizers in the door seal and the surface coating of the refrigerator's PCM board. In order to improve this problem, this application uses auxiliary agents 1,2-benzenedisulfonyl azide and tricresyl phosphate to produce a cross-linked network structure on the resin surface in the alloy, so that small molecules such as plasticizer DOTP are sealed in the alloy, thereby greatly improving the migration resistance of the refrigerator sealing strip.

[0018] Preferably, the stabilizer is: Ca / Zn composite stabilizer, epoxidized soybean oil and tetrahydroxymethyl cyclohexanol, and the mass ratio thereof is 1: (0.5-0.8): (0.2-0.5).

[0019] In practice, it is found that when the base material is PVC and TPEE, the pigment will precipitate when the color alloy is made, especially when the temperature is high. Therefore, the present application uses Ca / Zn composite stabilizer, epoxy soybean oil and tetrahydroxymethyl cyclohexanol in a specific ratio as stabilizers, which can make the pigment uniform and stable in the alloy.

[0020] In a second aspect, the present application discloses a method for preparing a PVC and TPEE blended modified alloy, comprising the following steps: S1: First, put TPEE, PVC SG3, antioxidant 626, lubricant, stabilizer, processing aid, TPEE premix, pigment, etc. into a high-speed mixer and mix to 60°C. Then, add epoxy soybean oil, DOTP and other plasticizers and mix to 90°C. Then, add heavy calcium and mix to 100°C before discharging. Among them, pigments account for 0-3% of the total weight of PVC and TPEE.

[0021] S2: The mixed material is put into an internal mixer for internal mixing to 150°C, and then the internal mixed PVC material is put into a single screw granulator for granulation to obtain alloy particles.

[0022] In the third aspect, the present application discloses a refrigerator sealing strip made of the above alloy, the low-temperature brittle temperature range of the refrigerator sealing strip is -45°C to -48°C, the low-temperature hardness change rate is <10%, the tensile strength is ≥15 MPa, the elongation at break is ≥300%, and the migration resistance is high.

[0023] Preferably, the manufacturing method of the refrigerator sealing strip is: putting the granulated particles into a single screw extruder to shape the door seal strip through an extrusion die; cutting the corners of the extruded door seal strip, passing the magnetic strip through the magnetic strip and welding it into a quadrilateral door seal.

[0024] In summary, in order to combine the advantages of PVC and TPEE resins, they need to be made into PVC-TPE alloys. The initial plan is to directly fuse TPEE and PVC through DOTP and epoxy soybean oil through other additives, but it is found that the interface of TPEE and PVC is difficult to penetrate each other. However, this application uses a viscosity reducer (cis-13-docoselenamide, cis-9-octadeceneamide and stearic acid octadecyl alcohol ester in a mass ratio of 1: (0.8-1.5): (0.2-0.6)) combined with 2000-3000 mesh talc, polyethylene glycol ester and polyethylene wax with an average molecular weight of 2000-5000 to make TPEE into a premix, and the premix is ​​processed with PVC and other additives to make PVC and TPEE better fused together to form a PVC-TPEE alloy with excellent low temperature resistance, low temperature flexibility and resilience. The refrigerator sealing strip made of this alloy makes the refrigerator have good sealing and less electricity consumption, thereby obtaining an environmentally friendly refrigerator sealing strip alloy.

[0025] In addition, if the processing time is relatively long when processing thick refrigerator sealing strips, the solvation process will be prolonged. At this time, the viscosity of the system will increase, which will affect the molding uniformity of the finished alloy product. The lubricant compounded by aluminum stearate and propylene glycol random polyether at a mass ratio of 1: (1.5-3.6) in this application can more fully reduce the system viscosity of PVC-TPEE, so that TPEE can always be better integrated with PVC during the processing process to form a uniform PVC-TPEE alloy, so as to use refrigerator sealing strips of various thicknesses.

[0026] Finally, since this application is a mixture of two resins, a certain proportion of small molecule plasticizer DOTP is selected to make the plasticizer penetrate well. Generally speaking, by adjusting the ratio of large molecules and small molecules, the migration and adhesion of the sealing strip can be controlled. However, in the PVC and TPEE system, adjusting the ratio and type of large molecule plasticizers and small molecule plasticizers will inevitably produce the phenomenon of sealing strip migration, which is specifically manifested in the adhesion of refrigerator sealing strips to the refrigerator, affecting the use and quality of the refrigerator, and also increasing electricity consumption. This application uses additives 1,2-benzenedisulfonyl azide and tricresyl phosphate to produce a cross-linked network structure on the resin surface in the alloy, so that small molecules such as plasticizer DOTP are sealed in the alloy, thereby greatly improving the migration resistance of the refrigerator sealing strip. DETAILED DESCRIPTION

[0027] Example Example 1 This embodiment discloses a refrigerator sealing strip made of a PVC and TPEE blended modified alloy, the raw materials are: 340 parts of PVCSG, 15 parts of TPEE prefabricated mixture, 6 parts of stabilizer (Ca / Zn composite stabilizer and epoxidized soybean oil are compounded in a mass ratio of 1:0.7), 32 parts of DOTP, 15 parts of heavy calcium, 1 part of processing aid (1,2-benzenedisulfonyl azide), 0.05 parts of antioxidant 626 and 0.05 parts of lubricant (compounded by aluminum stearate and glycerol random polyether in a mass ratio of 1:1.5). Among them, 1 part is 20g.

[0028] S1: First, put TPEE, PVC SG3, antioxidant 626, lubricant, stabilizer, processing aid, TPEE premix, pigment, etc. into a high-speed mixer and mix them to 60°C, then add epoxy soybean oil, DOTP and other plasticizers and mix them to 90°C, then add heavy calcium and mix them to 100°C before discharging; Among them, pigments account for 1% of the total weight of PVC and TPEE.

[0029] S2: The mixed material is put into an internal mixer for internal mixing to 150°C, and then the internal mixed PVC material is put into a single screw granulator for granulation to obtain alloy particles.

[0030] S3: Put the granulated particles into a single screw extruder to shape the door seal through an extrusion die, cut the extruded door seal at a 45-degree angle, pass the magnetic strip through the welding to form a quadrilateral door seal, and obtain a refrigerator seal. The thickness of the refrigerator seal is 2.5 cm.

[0031] The raw materials of TPEE prefabricated mixture are: 70 parts of ATPEE with Shore hardness of 80, 2 parts of viscosity reducer (compounded with cis-13-docosahexaenoic acid amide, cis-9-octadecenoic acid amide and stearyl stearate in a mass ratio of 1:0.8:0.2), 20 parts of talc powder with a mesh size of 2000-3000, 1 part of polyethylene glycol ester and 1 part of polyethylene wax with an average molecular weight of 2000-5000. Among them, 1 part is 10g.

[0032] TPEE, talcum powder, polyethylene glycol ester and polyethylene wax are put into a high-speed mixer for mixing and granulation, wherein the granulation temperature is 120°C in zone 1 of the feed port, 130°C in zone 2, 145°C in zone 3, 150°C in zone 4 and 150°C in the die zone, resulting in particles that are TPEE prefabricated mixtures.

[0033] Example 2 This embodiment discloses a refrigerator sealing strip made of a PVC and TPEE blended modified alloy, the raw materials are: 360 parts of PVCSG, 20 parts of TPEE prefabricated mixture, 10 parts of stabilizer (Ca / Zn composite stabilizer and epoxidized soybean oil are compounded in a mass ratio of 1:1.3), 35 parts of DOTP, 25 parts of heavy calcium, 3 parts of processing aid (1,2-benzenedisulfonyl azide), 0.3 parts of antioxidant 626 and 0.3 parts of lubricant (compounded by aluminum stearate and glycerol random polyether in a mass ratio of 1:3.6). Among them, 1 part is 20g.

[0034] S1: First, put TPEE, PVC SG3, antioxidant 626, lubricant, stabilizer, processing aid, TPEE premix, pigment, etc. into a high-speed mixer and mix them to 60°C, then add epoxy soybean oil, DOTP and other plasticizers and mix them to 90°C, then add heavy calcium and mix them to 100°C before discharging; Among them, pigments account for 1% of the total weight of PVC and TPEE.

[0035] S2: The mixed material is put into an internal mixer for internal mixing to 150°C, and then the internal mixed PVC material is put into a single screw granulator for granulation to obtain alloy particles.

[0036] S3: Put the granulated particles into a single screw extruder to shape the door seal through an extrusion die, cut the extruded door seal at a 45-degree angle, pass the magnetic strip through the welding to form a quadrilateral door seal, and obtain a refrigerator seal. The thickness of the refrigerator seal is 2.5 cm.

[0037] The raw materials of TPEE prefabricated mixture are: 70-80 parts of ATPEE with Shore hardness of 80, 5 parts of viscosity reducer (compounded with cis-13-docosahexaenoic acid amide, cis-9-octadecenoic acid amide and stearyl stearate in a mass ratio of 1:1.5:0.6), 30 parts of talc powder with a mesh size of 2000-3000, 3 parts of polyethylene glycol ester and 2 parts of polyethylene wax with an average molecular weight of 2000-5000. Among them, 1 part is 10g.

[0038] TPEE, talcum powder, polyethylene glycol ester and polyethylene wax are put into a high-speed mixer for mixing and granulation, wherein the granulation temperature is 130°C in the first zone of the feed port, 140°C in the second zone, 150°C in the third zone, 155°C in the fourth zone and 155°C in the die zone, resulting in particles that are TPEE prefabricated mixtures.

[0039] Example 3 This embodiment discloses a refrigerator sealing strip made of a PVC and TPEE blended modified alloy. The difference from Embodiment 1 is that the processing aids are 0.5 parts of 1,2-benzenedisulfonyl azide and 0.5 parts of tricresyl phosphate.

[0040] Example 4 This embodiment discloses a refrigerator sealing strip made of a PVC and TPEE blended modified alloy. The difference from Embodiment 1 is that the processing aids are 1.5 parts of 1,2-benzenedisulfonyl azide and 1.5 parts of tricresyl phosphate.

[0041] The low temperature resistance is improved, and the migration resistance of the refrigerator sealing strip is improved.

[0042] Example 5 This embodiment discloses a refrigerator sealing strip made of a PVC and TPEE blended modified alloy, wherein the stabilizer is a Ca / Zn composite stabilizer, epoxy soybean oil and tetrahydroxymethyl cyclohexanol, and the mass ratio thereof is 1:0.5:0.2.

[0043] Example 6 The stabilizer is a Ca / Zn composite stabilizer, epoxidized soybean oil and tetrahydroxymethyl cyclohexanol, with a mass ratio of 1:0.8:0.5, and color uniformity.

[0044] Comparative Example Comparative Example 1 The difference from Example 1 is that the viscosity reducer is prepared by compounding cis-13-docosahexylamide, cis-9-octadecenoic acid amide and stearyl stearate in a mass ratio other than 1:0.5:0.1.

[0045] Comparative Example 2 The difference from Example 1 is that the viscosity reducer uses an equal mass of cis-13-docosaenoic acid amide instead of cis-9-octadecenoic acid amide.

[0046] Comparative Example 3 The difference from Example 1 is that the lubricant is prepared by compounding aluminum stearate and glycerol random polyether in a mass ratio of 1:1.

[0047] Comparative Example 4 The difference from Example 1 is that the lubricant uses aluminum stearate of equal quality instead of glycerol random polyether.

[0048] Comparative Example 5 The difference from Example 1 is that the lubricant uses propylene glycol random polyether of equal quality instead of aluminum stearate.

[0049] Experimental testing 1. Low temperature resistance: Brittleness temperature GB / T 5470-2008 "Determination of brittleness temperature of plastics by impact method".

[0050] Change rate <10%, tensile strength ≥15mpa, elongation at break ≥300%, GB1040 2. Migration resistance 3. Weather resistance and aging resistance 4. Power consumption performance test 5. Magnetic determination GB 3217 TPEE and PVC are directly fused through DOTP and epoxy soybean oil through other additives, but it is found that the interface of TPEE and PVC is difficult to penetrate each other. This application uses a viscosity reducer (cis-13-docoselenamide, cis-9-octadeceneamide and stearyl stearate in a mass ratio of 1: (0.8-1.5): (0.2-0.6)) combined with 2000-3000 mesh talc, polyethylene glycol ester and polyethylene wax with an average molecular weight of 2000-5000 to make TPEE into a premix, and the premix is ​​processed with PVC and other additives to make PVC and TPEE better fused together to form a PVC-TPEE alloy with excellent low temperature resistance, low temperature flexibility and resilience. The refrigerator sealing strip made of this alloy makes the refrigerator have good sealing and less electricity consumption, thereby obtaining an environmentally friendly refrigerator sealing strip alloy.

[0051] The lubricant compounded by aluminum stearate and propylene glycol random polyether in a mass ratio of 1: (1.5-3.6) in the present application can more fully reduce the system viscosity of PVC-TPEE, so that TPEE can be better integrated with PVC during the processing process to form a PVC-TPEE alloy with uniform texture, thereby using refrigerator sealing strips of various thicknesses.

[0052] In order to make the plasticizer penetrate well, a certain proportion of small molecule plasticizer DOTP is selected. Generally speaking, adjusting the ratio of large molecule and small molecule plasticizers can effectively control the migration and adhesion of sealing strips. However, in the PVC and TPEE system, adjusting the ratio and type of large molecule plasticizers and small molecule plasticizers will inevitably produce the phenomenon of sealing strip migration, which is specifically manifested as the refrigerator sealing strip sticking to the refrigerator, affecting the use and quality of the refrigerator, and also increasing electricity consumption. The present application uses auxiliary agents 1,2-benzenedisulfonyl azide and tritolyl phosphate to produce a cross-linked network structure on the resin surface in the alloy, so that small molecules such as plasticizer DOTP are sealed in the alloy, thereby greatly improving the migration resistance of the refrigerator sealing strip.

[0053] The above-described embodiments are only preferred embodiments of the present invention, which are used to explain the present invention but are not used to limit the scope of the present invention. The invention name of the present invention has been described through specific embodiments. Those skilled in the art can refer to the content of the present invention to appropriately change the raw materials, process conditions and other links to achieve corresponding other purposes, and the relevant changes do not deviate from the content of the present invention. All similar replacements and modifications are obvious to those skilled in the art and are deemed to be included in the scope of the present invention.

Claims

1. A PVC and TPEE blended modified alloy, characterized in that: The composition includes the following components in parts by weight: PVC SG3 40-60 parts TPEE prefabricated mixture 15-20 parts Stabilizer 6-10 parts DOTP 32-35 copies 15-25 parts of heavy calcium 1-3 parts of processing aid Antioxidant 626 0.05-0.3 parts Lubricant 0.05-0.3 parts.

2. The PVC and TPEE blended modified alloy according to claim 1, characterized in that: The TPEE prefabricated mixture is composed of the following components in parts by mass: Shore hardness 80A TPEE Processing temperature below 150℃ 70-80 parts 2-5 parts of viscosity reducer 20-30 parts of talcum powder with mesh size of 2000-3000 Polyethylene glycol ester 1-3 parts 1-2 parts of polyethylene wax with an average molecular weight of 2000-5000.

3. The PVC and TPEE blended modified alloy according to claim 1, characterized in that: The lubricant is prepared by compounding aluminum stearate and glycerol random polyether in a mass ratio of 1:(1.5-3.6).

4. The PVC and TPEE blended modified alloy according to claim 1, characterized in that: The preparation method of the TPEE prefabricated mixture is: TPEE is mixed with talcum powder, polyethylene glycol ester and polyethylene wax and then granulated, wherein the granulation temperature is 120-130° C. in the feeding port zone 1, 130-140° C. in the zone 2, 145-150° C. in the zone 3, 150-155° C. in the zone 4 and 150-155° C. in the die zone, so that the particles are TPEE prefabricated mixture.

5. The PVC and TPEE blended modified alloy according to claim 1, characterized in that: The stabilizer is a Ca / Zn composite and 3-5 parts of epoxidized soybean oil.

6. The PVC and TPEE blended modified alloy according to claim 1, characterized in that: The processing aid is 0.5-1.5 parts of 1,2-benzenedisulfonyl azide and 0.5-1.5 parts of tricresyl phosphate.

7. The PVC and TPEE blended modified alloy according to claim 1, characterized in that: The stabilizer comprises: a Ca / Zn composite stabilizer, epoxy soybean oil and tetrahydroxymethyl cyclohexanol, and the mass ratio thereof is 1: (0.5-0.8): (0.2-0.5).

8. A method for preparing a PVC and TPEE blended modified alloy, characterized in that: The following steps are involved: S1: First, put TPEE, PVC SG3, antioxidant 626, lubricant, stabilizer, processing aid, TPEE premix, pigment, etc. into a high-speed mixer and mix to 60°C. Then, add epoxy soybean oil, DOTP and other plasticizers and mix to 90°C. Then, add heavy calcium and mix to 100°C before discharging. Among them, pigments account for 0-3% of the total weight of PVC and TPEE; S2: The mixed material is put into an internal mixer for internal mixing to 150°C, and then the internal mixed PVC material is put into a single screw granulator for granulation to obtain alloy particles.

9. A refrigerator sealing strip, characterized in that: Made of a modified alloy blended with any one of PVC in claims 1-7 and TPEE; The low-temperature brittle temperature range of the refrigerator sealing strip is -45°C to -48°C, the low-temperature hardness change rate is <10%, the tensile strength is ≥15 MPa, the elongation at break is ≥300%, and the migration resistance is high.

10. A refrigerator sealing strip according to claim 9, characterized in that: The manufacturing method of the refrigerator sealing strip comprises the following steps: putting the granulated particles into a single screw extruder to shape the door sealing strip through an extrusion die; cutting the corners of the extruded door sealing strip, passing the magnetic strip through the strip and welding the strip into a quadrilateral door sealing strip.