Ultra-low temperature nylon toughening agent, its preparation method and toughened nylon

Abstract

The present invention relates to the technical field of polymer materials, and particularly relates to an ultra-low temperature nylon toughening agent, a preparation method thereof, and toughened nylon. The ultra-low temperature nylon toughening agent is mainly prepared from the following components by weight: 95-98 parts of ethylene propylene diene monomer rubber, 1-3 parts of maleic anhydride, 0.1-1 part of initiator, 2-5 parts of polyether polyol, 2-5 parts of organic solvent, 0.1-1 part of antioxidant, and 0.5-1 part of ultraviolet absorber; the functionality of the polyether polyol is ≥3, and the number average molecular weight of the polyether polyol is 3000-5000. The nylon toughening agent of the present invention has excellent low temperature impact strength, has no odor, no small molecule migration, and has a simple preparation method. The toughened nylon prepared by using the ultra-low temperature nylon toughening agent of the present invention has a significantly improved impact strength at ultra-low temperature (-40°C).

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to an ultra-low temperature nylon toughening agent, a preparation method thereof, and toughened nylon. Background Art

[0002] As a commonly used polymer material, nylon has the advantages of high mechanical strength, easy processing, good heat resistance, wear resistance, chemical solvent resistance, self-lubrication, and good flame retardant performance. However, the low-temperature toughness of nylon is poor, which limits its application in certain specific environments. Therefore, in order to improve the low-temperature toughness of nylon and meet the needs of a wider range of industrial applications, nylon usually needs to be toughened.

[0003] Currently, there are mainly two types of nylon toughening agents: one is a nylon toughening agent based on polyolefin grafted maleic anhydride or ethylene propylene diene monomer grafted maleic anhydride; the other is a nylon toughening agent based on polyolefin grafted silane. The first type of nylon toughening agent has the advantages of simple preparation and low cost, but its low-temperature impact strength is relatively low and the odor is relatively large. The second type of nylon toughening agent has good low-temperature impact performance and low odor, but due to the large amount of residual organosilane monomers, it is easy to precipitate and migrate to the material surface, resulting in a decline in material performance.

[0004] Chinese Patent Application with Publication No. CN110591100A discloses an ultra-low temperature resistant nylon toughening agent, which is obtained by grafting a polar monomer onto a polyolefin elastomer and then reacting with amino silicone oil. A large amount of amino silicone oil is added to this nylon toughening agent, resulting in a large amount of residual organosilicon monomers, and problems such as monomer precipitation and migration are likely to occur during use, leading to a decline in material performance. Chinese Patent Application with Publication No. CN109880360A discloses a nylon composite material resistant to high-cold impact, which uses a modified toughening agent and a compounded cold-resistant plasticizer to be blended with nylon to improve the low-temperature impact resistance of nylon. The modified toughening agent is a product obtained by grafting a polyolefin or a polyurethane elastomer with a grafting agent. Although this application uses both a plasticizer and a toughening agent to modify nylon at the same time, multiple material blending preparations are required, and the preparation process is cumbersome and the process is complex.

[0005] The above-mentioned solutions all improve the toughness of nylon to a certain extent. With the application and popularization of nylon materials in high-cold regions, nylon needs to withstand high-cold environments, and the high-cold impact strength and toughness of nylon materials need to be further improved.

[0006] In view of this, the present invention is specifically proposed. Summary of the Invention

[0007] The purpose of the present invention is to provide an ultra-low temperature nylon toughening agent, a preparation method thereof, and toughened nylon. The nylon toughening agent of the present invention has excellent low-temperature impact strength, no odor, no small molecule migration, and a simple preparation method.

[0008] To achieve the above object of the present invention, the first aspect of the present invention provides a super-low temperature nylon toughening agent, which is mainly prepared from the following components by weight:

[0009] 95-98 parts of ethylene propylene diene monomer rubber, 1-3 parts of maleic anhydride, 0.1-1 part of initiator, 2-5 parts of polyether polyol, 2-5 parts of organic solvent, 0.1-1 part of antioxidant and 0.5-1 part of ultraviolet absorber;

[0010] The functionality of the polyether polyol is ≥3, and the number average molecular weight of the polyether polyol is 3000-5000.

[0011] In a specific embodiment of the present invention, the polyether polyol is a polyether triol with a number average molecular weight of 3000-5000.

[0012] In a specific embodiment of the present invention, the mass ratio of the maleic anhydride to the polyether polyol is 1:(1-2).

[0013] In a specific embodiment of the present invention, the third monomer of the ethylene propylene diene monomer rubber is ethylidene norbornene.

[0014] In a specific embodiment of the present invention, the density of the ethylene propylene diene monomer rubber is ≤0.88 g / cm 3 .

[0015] In a specific embodiment of the present invention, the initiator includes at least one of peroxide initiators. Further, the initiator includes at least one of dicumyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, tert-butyl laurate peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, tert-butyl cumyl peroxide, tert-butyl benzoate peroxide and tert-butyl acetate peroxide.

[0016] In a specific embodiment of the present invention, the organic solvent includes ethyl acetate.

[0017] The second aspect of the present invention provides a preparation method of the super-low temperature nylon toughening agent of the first aspect of the present invention, including the following steps:

[0018] Mix the ethylene propylene diene monomer rubber, maleic anhydride and initiator in proportion and carry out melt extrusion;

[0019] Add a mixture of polyether polyol, antioxidant, ultraviolet absorber and organic solvent at the end of the melt extrusion.

[0020] In a specific embodiment of the present invention, the temperature of the melt extrusion is 80-150°C.

[0021] The third aspect of the present invention provides a toughened nylon, which comprises nylon and the ultra-low temperature nylon toughening agent of the first aspect of the present invention.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) In the present invention, maleic anhydride is grafted onto ethylene-propylene-diene monomer (EPDM), and polyether polyol with excellent low-temperature toughness is introduced at the same time. By utilizing the reaction between maleic anhydride and polyether polyol, the polyether polyol is grafted onto the molecular chain of EPDM, and the energy is fully dissipated under external force, thus significantly improving the toughness of the material. At the same time, the polyether polyol is connected to EPDM in a grafted manner, avoiding the problem of material property degradation caused by the migration of polyether polyol.

[0024] (2) The preparation method of the ultra-low temperature nylon toughening agent of the present invention is simple in operation and can be obtained only by one-step melt extrusion, which is conducive to large-scale industrial production. The toughened nylon prepared by using the ultra-low temperature nylon toughening agent of the present invention has a significantly improved impact strength at ultra-low temperature (-40 °C). Specific Embodiments

[0025] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention. Those not specified in the embodiments are carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not specified in the manufacturer are all conventional products that can be obtained through commercial purchase.

[0026] The first aspect of the present invention provides an ultra-low temperature nylon toughening agent, which is mainly prepared from the following components by weight: 95-98 parts of ethylene-propylene-diene monomer (EPDM), 1-3 parts of maleic anhydride, 0.1-1 part of initiator, 2-5 parts of polyether polyol, 2-5 parts of organic solvent, 0.1-1 part of antioxidant, and 0.5-1 part of ultraviolet absorber;

[0027] The functionality of the polyether polyol ≥ 3, and the number-average molecular weight of the polyether polyol is 3000-5000.

[0028] In the present invention, maleic anhydride is grafted onto ethylene propylene diene monomer (EPDM) rubber, and polyether polyol with excellent low-temperature toughness is introduced. By using the reaction between maleic anhydride and polyether polyol, the polyether polyol is grafted onto the molecular chain of EPDM rubber, and under external force, energy is dissipated sufficiently, thus significantly improving the toughness of the material. At the same time, the polyether polyol is connected to the EPDM rubber in a grafting manner, avoiding the problem of material property degradation caused by the migration of polyether polyol.

[0029] As a toughening agent matrix, EPDM rubber can, to a certain extent, hinder crack propagation and provide energy absorption, thereby improving the toughness of nylon. Based on EPDM rubber, the present invention grafts maleic anhydride and then grafts polyether polyol through reaction, significantly improving the impact strength of nylon in an ultra-low temperature environment, etc. In different embodiments, by weight, the amount of EPDM rubber used can be 95 parts, 96 parts, 97 parts, 98 parts, or the range composed of any two of them.

[0030] After maleic anhydride is grafted onto EPDM rubber, on the one hand, the functional groups of maleic anhydride can react with polyether polyol to graft the polyether polyol onto the EPDM rubber chain, making full use of the characteristics of polyether polyol and avoiding the migration of polyether polyol. On the other hand, the remaining functional groups of maleic anhydride can react with the functional groups in the molecular chain of the nylon matrix, further improving the compatibility between the nylon toughening agent and the nylon matrix. However, the inventors of the present invention have found that if the amount of maleic anhydride used is too high, although the compatibility is improved, too much maleic anhydride will react excessively with nylon, forming too many chemical bonds and affecting the overall performance of the nylon material. If the amount of maleic anhydride used is too low, the compatibility cannot be guaranteed, and the amount of graftable polyether polyol is limited, resulting in limited toughening effect on nylon. In the present invention, by weight, the amount of maleic anhydride is regulated to be 1 to 3 parts, for example, it can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, or the range composed of any two of them, which helps to balance the compatibility with nylon, the toughening effect on nylon, and the overall performance of the toughened nylon.

[0031] Polyether polyols have a flexible ether bond structure. These flexible chain segments can play an isolating and buffering role between the rigid molecular chains of nylon. Polyether polyols can absorb and disperse the externally applied energy, effectively preventing the propagation of cracks in nylon materials. At the same time, for an appropriate amount of polyether polyols, the hydroxyl groups in their structure can form hydrogen bonds with groups such as amide bonds on the nylon molecular chains, improving the interfacial binding force between the two and better exerting the toughening effect of polyether polyols. In the present invention, by grafting polyether polyols onto ethylene-propylene-diene rubber (EPDM), on the one hand, the migration of polyether polyols is effectively avoided, and on the other hand, the dispersibility of polyether polyols in nylon is significantly improved. Multiple synergies significantly improve the toughening effect on nylon. When the dosage of polyether polyols is too low, the toughening effect is not obvious; while when the dosage of polyether polyols is too high, too much polyether polyols cannot be effectively grafted onto EPDM completely, and the free polyether polyols may cause phase separation, which will not only significantly reduce the strength of nylon materials but also fail to exert the toughening effect. In the present invention, calculated by weight parts, the dosage of polyether polyols is regulated to be 2 - 5 parts, for example, it can be 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts or the range composed of any two of them, which helps to improve the toughening effect and ensure the properties such as the strength of nylon materials.

[0032] In different embodiments, calculated by weight parts, the dosages of the initiator, organic solvent, antioxidant, and ultraviolet absorber can be as follows:

[0033] The dosage of the initiator can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part or the range composed of any two of them; the dosage of the organic solvent can be 2 parts, 3 parts, 4 parts, 5 parts or the range composed of any two of them; the dosage of the antioxidant can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part or the range composed of any two of them; the dosage of the ultraviolet absorber can be 0.5 part, 0.6 part, 0.8 part, 1 part or the range composed of any two of them.

[0034] The functionality of the polyether polyols of the present invention is ≥3, for example, it can be 3, 4, 5, etc. Using polyether polyols with a functionality of more than 3 can, on the one hand, form appropriate crosslinking within the toughening agent itself, and on the other hand, can form appropriate physical or chemical crosslinking with nylon materials, taking into account the improvement of the toughening effect on nylon and the improvement of strength.

[0035] The number-average molecular weight of the polyether polyol of the present invention is 3,000 to 5,000, and for example, it can be 3,000, 3,200, 3,500, 3,800, 4,000, 4,200, 4,500, 4,800, 5,000 or the range composed of any two of them. The inventors of the present invention have found through research that when the number-average molecular weight of the polyether polyol is small, its molecular chain is short, and the flexible chain segments that can be provided are limited, and it is unable to effectively prevent the propagation of cracks in the nylon matrix, resulting in an insignificant toughening effect; when the number-average molecular weight of the polyether polyol is too large, the molecular chain is too long, and the compatibility with the matrix becomes poor, resulting in difficulties in uniform dispersion during the processing and mixing process, and problems such as agglomeration are likely to occur, and the toughening effect cannot be well exerted. Using a polyether polyol that meets the above molecular weight range can significantly improve the low-temperature toughening effect on nylon.

[0036] In a specific embodiment of the present invention, the polyether polyol is a polyether triol with a number-average molecular weight of 3,000 to 5,000.

[0037] In a specific embodiment of the present invention, the mass ratio of maleic anhydride to the polyether polyol is 1:(1 to 2), and for example, it can be 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2 or the range composed of any two of them. The polyether polyol is grafted onto the ethylene-propylene-diene monomer (EPDM) through the reaction with maleic anhydride. Controlling the mass of maleic anhydride and the polyether polyol within the above range is more conducive to taking into account the grafting situation of the polyether polyol and ensuring the compatibility between the toughening agent and nylon, thereby fully improving the low-temperature toughening effect.

[0038] In a specific embodiment of the present invention, the third monomer of the ethylene-propylene-diene monomer (EPDM) is ethylidene norbornene. Further, the ethylene content in the ethylene-propylene-diene monomer (EPDM) is 65% to 75%, and for example, it can be 65%, 68%, 70%, 72%, 75% or the range composed of any two of them.

[0039] Ethylene-propylene-diene monomer (EPDM) is a copolymer of ethylene, propylene and a small amount of non-conjugated diene third monomer. Using ethylene-propylene-diene monomer (EPDM) with ethylidene norbornene as the third monomer, the ethylidene norbornene structural unit in its molecular chain can effectively store and release energy. Compared with other third monomers, it has better low-temperature flexibility and elongation at break, and thus is more helpful to prevent the nylon material from brittle cracking at low temperatures.

[0040] In a specific embodiment of the present invention, the density of the ethylene-propylene-diene monomer (EPDM) ≤ 0.88 g / cm 3 , and for example, it can be 0.88 g / cm 3 , 0.878 g / cm 3 , 0.875 g / cm 3 , 0.872 g / cm 3 , 0.87 g / cm 3, 0.868 g / cm 3 , 0.865 g / cm 3 , 0.862 g / cm 3 , 0.86 g / cm 3 or the range composed of any two of them. The inventors of the present invention have found through research that when using ethylene-propylene-diene monomer rubber with a density > 0.88 g / cm 3 , it will lead to a decrease in low-temperature impact strength.

[0041] In the specific embodiments of the present invention, the initiator includes at least one of peroxide initiators. Further, the initiator includes at least one of dicumyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, tert-butyl lauroperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, tert-butylcumyl peroxide, tert-butyl benzoate peroxide, and tert-butyl acetate peroxide.

[0042] The organic solvent is used to pre-dissolve the polyether polyol, antioxidant, and anti-ultraviolet agent to ensure uniform mixing of the materials during the preparation process. In the specific embodiments of the present invention, the organic solvent includes, but is not limited to, ethyl acetate.

[0043] In the specific embodiments of the present invention, the antioxidant includes at least one of hindered phenol antioxidants and phosphite antioxidants.

[0044] In the specific embodiments of the present invention, the anti-ultraviolet agent includes at least one of benzotriazole light absorbers, triazine light stabilizers, and hindered amine light stabilizers.

[0045] The second aspect of the present invention provides a preparation method of the ultra-low temperature nylon toughening agent of the first aspect of the present invention, including the following steps: mixing ethylene-propylene-diene monomer rubber, maleic anhydride, and an initiator in proportion and performing melt extrusion;

[0046] Adding a mixture of polyether polyol, antioxidant, anti-ultraviolet agent, and organic solvent at the end of the melt extrusion.

[0047] In actual operation, the above preparation method is carried out in a twin-screw extruder. First, a mixed solution is obtained by mixing polyether polyol, antioxidant, anti-ultraviolet agent, and organic solvent; ethylene-propylene-diene monomer rubber, maleic anhydride, and an initiator are mixed evenly in a mixing kettle, placed in the hopper of the extruder, and melt-extruded in the twin-screw extruder. At the end of the extrusion, the mixed solution is injected into the extruder by a metering pump to participate in the reaction.

[0048] In a specific embodiment of the present invention, the extrusion temperature is 80 to 150 °C. Specifically, the temperature settings of each temperature zone of the twin-screw extruder are 80 °C, 120 °C, 150 °C, 150 °C, 150 °C, 150 °C, 150 °C, and 150 °C in sequence.

[0049] The third aspect of the present invention provides a toughened nylon, comprising nylon and the ultra-low temperature nylon toughening agent of the first aspect of the present invention.

[0050] In a specific embodiment of the present invention, the mass ratio of nylon to the ultra-low temperature nylon toughening agent is 100:(5 - 20).

[0051] In actual operation, the preparation of the toughened nylon includes: nylon and the ultra-low temperature nylon toughening agent are extruded and pelletized at 250 - 260 °C.

[0052] Example 1

[0053] This example provides an ultra-low temperature nylon toughening agent, and its raw materials include the following components in parts by weight: 95 parts of ethylene propylene diene monomer rubber, 3 parts of maleic anhydride, 0.5 part of initiator, 5 parts of polyether polyol, 5 parts of ethyl acetate, 0.5 part of antioxidant, and 0.5 part of ultraviolet absorber.

[0054] Among them, the ethylene propylene diene monomer rubber is EPDM Dow 3722P of the United States; the maleic anhydride is of analytical purity; the initiator is dicumyl peroxide; the polyether polyol is a polyether triol with a number average molecular weight of 3000 - 5000 (model HSH-330); the antioxidant is antioxidant B215; the ultraviolet absorber is ultraviolet absorber 770.

[0055] The preparation method of the ultra-low temperature nylon toughening agent in this example includes the following steps:

[0056] (1) Mix and dissolve the polyether polyol, ethyl acetate, antioxidant, and ultraviolet absorber to obtain a mixed solution.

[0057] (2) Mix the ethylene propylene diene monomer rubber, maleic anhydride, and initiator evenly in a mixing kettle, place the mixed material in the hopper of the twin-screw extruder, melt and extrude in the twin-screw extruder, and use a metering pump to inject the mixed solution in step (1) into the extruder at the end of extrusion to participate in the reaction. The temperature settings of each temperature zone of the twin-screw extruder are 80 °C, 120 °C, 150 °C, 150 °C, 150 °C, 150 °C, 150 °C, and 150 °C in sequence.

[0058] Example 2

[0059] This example refers to the ultra-low temperature nylon toughening agent and its preparation method in Example 1, and the difference is only that: the dosage of the polyether polyol is different.

[0060] The dosage of the polyether polyol in this example is 3 parts by weight, and the rest is the same as in Example 1.

[0061] Example 3

[0062] This example refers to the ultra-low temperature nylon toughening agent and its preparation method in Example 1, the difference is only that: the dosage of maleic anhydride is different.

[0063] The dosage of maleic anhydride in this example is 2 parts by weight, and the rest is the same as in Example 1.

[0064] Example 4

[0065] This example refers to the ultra-low temperature nylon toughening agent and its preparation method in Example 1, the difference is only that: the dosages of maleic anhydride and polyether polyol are different.

[0066] The dosage of maleic anhydride in this example is 2 parts, and the dosage of polyether polyol is 3 parts, and the rest is the same as in Example 1.

[0067] Example 5

[0068] This example refers to the ultra-low temperature nylon toughening agent and its preparation method in Example 1, the difference is only that: the dosages of maleic anhydride and polyether polyol are different.

[0069] The dosage of maleic anhydride in this example is 3 parts, and the dosage of polyether polyol is 2 parts, and the rest is the same as in Example 1.

[0070] Example 6

[0071] This example refers to the ultra-low temperature nylon toughening agent and its preparation method in Example 1, the difference is only that: the dosages of maleic anhydride and polyether polyol are different.

[0072] The dosage of maleic anhydride in this example is 1 part, and the dosage of polyether polyol is 4 parts, and the rest is the same as in Example 1.

[0073] Comparative Example 1

[0074] Comparative Example 1 refers to the ultra-low temperature nylon toughening agent and its preparation method in Example 1, the difference is that: the type of polyether polyol is different.

[0075] The polyether polyol in Comparative Example 1 is a polyether diol with a number average molecular weight of 3000-5000 (model DL-3000D).

[0076] Comparative Example 2

[0077] Comparative Example 2 refers to the ultra-low temperature nylon toughening agent and its preparation method in Example 1, the difference is that: the type of polyether polyol is different.

[0078] The polyether polyol of Comparative Example 2 is a polyether triol with a number average molecular weight lower than 3000 (model number TO330).

[0079] Comparative Example 3

[0080] Comparative Example 3 refers to the ultra-low temperature nylon toughening agent and its preparation method of Example 1, the differences are: the raw materials of Comparative Example 3 do not include polyether polyol, ethyl acetate, antioxidant and ultraviolet absorber; and in the preparation, there is no need to add the mixed solution through a metering pump at the end. The rest are the same as in Example 1.

[0081] Comparative Example 4

[0082] Comparative Example 4 refers to the ultra-low temperature nylon toughening agent and its preparation method of Example 1, the differences are: the raw materials of Comparative Example 4 do not include maleic anhydride and initiator; and in the preparation, there is no need to add maleic anhydride and initiator in step (2). The rest are the same as in Example 1.

[0083] Comparative Example 5

[0084] Comparative Example 5 refers to the ultra-low temperature nylon toughening agent and its preparation method of Example 1, the difference is: the dosage of polyether polyol is different.

[0085] The dosage of polyether polyol in Comparative Example 5 is 8 parts, and the rest are the same as in Example 1.

[0086] Experimental Example

[0087] The toughening agents prepared in different Examples and Comparative Examples were made into test specimens and the following tests were carried out. The test results are shown in Table 1.

[0088] Preparation of specimens: Weigh nylon 6 and the toughening agent according to a mass ratio of 100:15, mix them evenly through a high-speed mixer, then extrude and pelletize at 250 °C and carry out conventional injection molding to form standard samples. The injection molding process settings are: injection temperature is 200 °C, injection pressure is 17 MPa.

[0089] Table 1 Test results of different toughening agents

[0090]

[0091] From the above test results, it can be seen that in the present invention, maleic anhydride is grafted onto ethylene-propylene-diene monomer (EPDM), and at the same time, a polyether polyol with excellent low-temperature toughness is introduced, and the polyether polyol is grafted onto the molecular chain of EPDM by the reaction of maleic anhydride and polyether polyol, and the energy is fully dissipated under external force, thereby significantly improving the toughness of the material. The toughened nylon prepared with the ultra-low temperature nylon toughening agent of the present invention has a significantly improved impact strength at ultra-low temperature (-40 °C).

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. Ultra-low temperature nylon toughening agent, characterized in that: It is mainly made of the following components by weight: 95-98 parts of EPDM rubber, 1-3 parts of maleic anhydride, 0.1-1 parts of initiator, 2-5 parts of polyether polyol, 2-5 parts of organic solvent, 0.1-1 parts of antioxidant and 0.5-1 parts of anti-ultraviolet agent; The functionality of the polyether polyol is ≥3, and the number average molecular weight of the polyether polyol is 3000 to 5000; The preparation method of the ultra-low temperature nylon toughening agent comprises the following steps: mixing EPDM rubber, maleic anhydride and initiator in proportion, and performing melt extrusion; A mixture of polyether polyol, antioxidant, anti-ultraviolet agent and organic solvent is added to the end of the melt extrusion.

2. The ultra-low temperature nylon toughening agent according to claim 1, characterized in that: The polyether polyol is a polyether triol with a number average molecular weight of 3000 to 5000.

3. The ultra-low temperature nylon toughening agent according to claim 1, characterized in that: The mass ratio of the maleic anhydride to the polyether polyol is 1:(1-2).

4. The ultra-low temperature nylon toughening agent according to claim 1, characterized in that: The third monomer of the EPDM rubber is ethylidene norbornene.

5. The ultra-low temperature nylon toughening agent according to claim 1, characterized in that: The density of the EPDM rubber is ≤0.88 g / cm 3 .

6. The ultra-low temperature nylon toughening agent according to claim 1, characterized in that: The initiator comprises at least one of dicumyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, tert-butylisopropyl peroxide, tert-butyl peroxybenzoate and tert-butyl peroxyacetate.

7. The ultra-low temperature nylon toughening agent according to claim 1, characterized in that: The organic solvent includes ethyl acetate.

8. The ultra-low temperature nylon toughening agent according to claim 1, characterized in that: The temperature of the melt extrusion is 80-150°C.

9. Toughened nylon, characterized in that: The invention comprises nylon and the ultra-low temperature nylon toughening agent according to any one of claims 1 to 8.

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