Ultralow-temperature nylon flexibilizer, preparation method thereof and toughened nylon

Abstract

The invention relates to the technical field of high polymer materials, in particular to an ultralow-temperature nylon toughening agent, a preparation method thereof and toughened nylon. The ultralow-temperature nylon toughening agent is mainly prepared from the following components in parts by weight: 95 to 98 parts of ethylene propylene diene monomer, 1 to 3 parts of maleic anhydride, 0.1 to 1 part of an initiator, 2 to 5 parts of polyether polyol, 2 to 5 parts of an organic solvent, 0.1 to 1 part of an antioxidant and 0.5 to 1 part of an anti-ultraviolet agent, the functionality of the polyether polyol is greater than or equal to 3, and the number-average molecular weight of the polyether polyol is 3000-5000. The nylon toughening agent disclosed by the invention has excellent low-temperature impact strength, is odorless, does not have small molecule migration, and is simple in preparation method. The impact strength of toughened nylon prepared by adopting the ultralow-temperature nylon toughening agent disclosed by the invention at ultralow temperature (-40 DEG C) is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to an ultra-low temperature nylon toughening agent and 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 retardancy. However, nylon has poor low-temperature toughness, 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] There are two main types of nylon toughening agents at present: one is a nylon toughening agent grafted with maleic anhydride by polyolefin or EPDM rubber grafted with maleic anhydride; the other is a nylon toughening agent grafted with silane by polyolefin. 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 it has a strong odor. The second type of nylon toughening agent has better low-temperature impact performance and lower odor, but due to the large amount of residual organosilane monomers, it is easy to precipitate and migrate to the surface of the material, resulting in a decrease in material performance.

[0004] The Chinese patent application with publication number CN110591100A records a nylon toughening agent resistant to ultra-low temperatures, which is obtained by grafting polar monomers onto polyolefin elastomers and then reacting with amino silicone oil. A large amount of amino silicone oil is added to the nylon toughening agent, resulting in a large amount of residual silicone monomers. During use, problems such as monomer precipitation and migration are prone to occur, resulting in a decrease in material performance. The Chinese patent application with publication number CN109880360A records a high-cold impact-resistant nylon composite material, which uses a modified toughening agent and a compounded cold-resistant plasticizer to blend with nylon to improve the low-temperature impact resistance of nylon. The modified toughening agent is a product of polyolefin or polyurethane elastomer grafted with a grafting agent. Although the application uses plasticizers and toughening agents to modify nylon at the same time, multiple material blending preparations are required, and the preparation process is cumbersome and the process is complicated.

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

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

[0007] The purpose of the present invention is to provide an ultra-low temperature nylon toughening agent and a preparation method thereof and toughened nylon. The nylon toughening agent of the present invention has excellent low-temperature impact strength, is odorless, does not have small molecule migration, and has a simple preparation method.

[0008] In order to achieve the above-mentioned object of the present invention, the first aspect of the present invention provides an ultra-low temperature nylon toughening agent, which is mainly prepared by the following components in parts 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 3000-5000.

[0009] In a specific embodiment of the present invention, the polyether polyol is a polyether triol having a number average molecular weight of 3000 to 5000.

[0010] In a specific embodiment of the present invention, the mass ratio of the maleic anhydride to the polyether polyol is 1:(1-2).

[0011] In a specific embodiment of the present invention, the third monomer of the EPDM rubber is ethylidene norbornene.

[0012] In a specific embodiment of the present invention, the density of the EPDM rubber is ≤0.88 g / cm 3 .

[0013] 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 peroxylaurate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, tert-butylisopropyl peroxide, tert-butyl peroxybenzoate and tert-butyl peroxyacetate.

[0014] In a specific embodiment of the present invention, the organic solvent comprises ethyl acetate.

[0015] The second aspect of the present invention provides a method for preparing the ultra-low temperature nylon toughening agent of the first aspect of the present invention, comprising the following steps: EPDM rubber, maleic anhydride and initiator are mixed in proportion and melt-extruded; A mixture of polyether polyol, antioxidant, anti-ultraviolet agent and organic solvent is added to the end of the melt extrusion.

[0016] In a specific embodiment of the present invention, the temperature of the melt extrusion is 80-150°C.

[0017] 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.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention grafts maleic anhydride onto EPDM rubber and simultaneously introduces polyether polyol having excellent low-temperature toughness. The polyether polyol is grafted onto the molecular chain of EPDM rubber by the reaction between maleic anhydride and polyether polyol, and the energy is fully dissipated under external force, thereby significantly improving the toughness of the material. At the same time, the polyether polyol is grafted onto the EPDM rubber, thereby avoiding the problem of material performance degradation caused by the migration of the polyether polyol. (2) The preparation method of the ultra-low temperature nylon toughening agent of the present invention is simple to operate and can be obtained by only one step of melt extrusion, which is conducive to large-scale industrial production; the impact strength of the toughened nylon prepared by using the ultra-low temperature nylon toughening agent of the present invention at ultra-low temperature (-40°C) is significantly improved. DETAILED DESCRIPTION

[0019] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0020] 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 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 3000-5000.

[0021] The present invention grafts maleic anhydride onto EPDM rubber, and simultaneously introduces polyether polyol with excellent low-temperature toughness, and utilizes the reaction between maleic anhydride and polyether polyol to graft the polyether polyol into the molecular chain of EPDM rubber, so that energy is fully dissipated under external force, thereby significantly improving the toughness of the material; at the same time, the polyether polyol is connected to the EPDM rubber in a grafting manner, thereby avoiding the problem of material performance degradation caused by the migration of the polyether polyol.

[0022] As a toughening agent matrix, EPDM rubber can hinder crack propagation and provide energy absorption to a certain extent, thereby improving the toughness of nylon. The present invention grafts maleic anhydride on the basis of EPDM rubber, and then grafts polyether polyol by reaction, thereby significantly improving the impact strength of nylon in ultra-low temperature environment. For example, in different embodiments, the amount of EPDM rubber can be 95 parts, 96 parts, 97 parts, 98 parts or a range consisting of any two of them by weight.

[0023] After maleic anhydride is grafted onto EPDM rubber, the functional groups of maleic anhydride can react with polyether polyols on the one hand, grafting polyether polyols onto the EPDM rubber chain, making full use of the characteristics of polyether polyols and avoiding the migration of polyether polyols; 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 of the nylon toughening agent with the nylon matrix. However, the inventors of the present invention have found that if the amount of maleic anhydride is too high, although the compatibility is improved, too much maleic anhydride will over-react with nylon, forming too many chemical bonds, affecting the overall performance of the nylon material; if the amount of maleic anhydride is too low, compatibility cannot be guaranteed, and the polyether polyols that can be grafted are limited, and the toughening effect on nylon is limited. In the present invention, the amount of maleic anhydride is regulated to be 1 to 3 parts by weight, for example, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts or any two parts thereof, thereby helping to ensure compatibility with nylon, the toughening effect on nylon and the overall performance of the toughened nylon.

[0024] Polyether polyol has a flexible ether bond structure. These flexible chain segments can play an isolating and buffering role between the rigid molecular chains of nylon. Polyether polyol can absorb and disperse the added energy, effectively preventing the expansion of cracks in nylon materials. At the same time, the hydroxyl groups in the structure of an appropriate amount of polyether polyol can form hydrogen bonds with groups such as amide bonds on the nylon molecular chain, improve the interfacial bonding force between the two, and better play the toughening effect of polyether polyol. The present invention grafts polyether polyol onto EPDM rubber, on the one hand, effectively avoiding the migration of polyether polyol, on the other hand, significantly improving the dispersibility of polyether polyol in nylon, and synergizing to significantly improve the toughening effect of nylon. When the amount of polyether polyol is too low, the toughening effect is not obvious; and when the amount of polyether polyol is too high, too much polyether polyol cannot be effectively grafted to EPDM rubber, and the free polyether polyol may cause phase separation, which not only significantly reduces the strength of the nylon material, but also fails to play a toughening effect. The present invention regulates the amount of polyether polyol to be 2 to 5 parts by weight, for example, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts or any two of them, thereby helping to improve the toughening effect and ensure the strength and other properties of the nylon material.

[0025] For example, in different embodiments, the amounts of the initiator, the organic solvent, the antioxidant and the anti-ultraviolet agent may be as follows, respectively, by weight: The amount of the initiator can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part or a range consisting of any two of them; the amount of the organic solvent can be 2 parts, 3 parts, 4 parts, 5 parts or a range consisting of any two of them; the amount of the antioxidant can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part or a range consisting of any two of them; the amount of the anti-ultraviolet agent can be 0.5 part, 0.6 part, 0.8 part, 1 part or a range consisting of any two of them.

[0026] The functionality of the polyether polyol of the present invention is ≥3, for example, it can be 3, 4, 5, etc. The use of polyether polyols with a functionality of 3 or more can form appropriate crosslinks in the toughening agent itself on the one hand, and can form appropriate physical or chemical crosslinks with the nylon material on the other hand, taking into account the improvement of the toughening effect and strength of nylon.

[0027] The number average molecular weight of the polyether polyol of the present invention is 3000-5000, for example, it can be 3000, 3200, 3500, 3800, 4000, 4200, 4500, 4800, 5000 or any two thereof. The inventors of the present invention have found that when the number average molecular weight of the polyether polyol is small, its molecular chain is short, the flexible chain segment that can be provided is limited, and it cannot effectively prevent the expansion 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 difficulty in uniform dispersion during processing and mixing, and problems such as agglomeration are prone to occur, and the toughening effect cannot be well exerted. The use of polyether polyols that meet the above molecular weight range can significantly improve the low-temperature toughening effect on nylon.

[0028] In a specific embodiment of the present invention, the polyether polyol is a polyether triol having a number average molecular weight of 3000 to 5000.

[0029] In a specific embodiment of the present invention, the mass ratio of maleic anhydride to polyether polyol is 1: (1-2), for example, it can be 1: 1, 1: 1.2, 1: 1.5, 1: 1.8, 1: 2 or any two thereof. Polyether polyol is grafted to EPDM rubber by reacting with maleic anhydride. Regulating the mass of maleic anhydride and polyether polyol within the above range is more conducive to ensuring the grafting of polyether polyol and the compatibility of toughening agent with nylon, thereby fully improving the low-temperature toughening effect.

[0030] In a specific embodiment of the present invention, the third monomer of the EPDM rubber is ethylidene norbornene. Further, the ethylene content in the EPDM rubber is 65% to 75%, for example, 65%, 68%, 70%, 72%, 75% or any two thereof.

[0031] EPDM rubber is a copolymer of ethylene, propylene and a small amount of non-conjugated diene third monomer. The EPDM rubber using ethylidene norbornene as the third monomer has ethylidene norbornene structural units in its molecular chain that can effectively store and release energy. Compared with other third monomers, it has better low-temperature flexibility and elongation at break, which helps to prevent nylon materials from brittle cracking at low temperatures.

[0032] In a specific embodiment of the present invention, the density of EPDM rubber is ≤0.88 g / cm 3 , for example, it can be 0.88 g / cm 3 , 0.878g / cm 3 , 0.875g / cm 3 , 0.872g / cm 3 , 0.87g / cm 3 , 0.868g / cm 3 , 0.865g / cm 3 , 0.862g / cm 3 , 0.86g / cm 3 Or any two of them. The inventors of the present invention have found that when the density is greater than 0.88 g / cm 3 When EPDM rubber is used, the low temperature impact strength will be reduced.

[0033] In a specific embodiment of the present invention, the initiator includes at least one of the peroxide initiators. Further, the initiator includes 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.

[0034] The organic solvent is used to dissolve the polyether polyol, antioxidant and anti-ultraviolet agent in advance to ensure that the materials are mixed evenly during the preparation process. In a specific embodiment of the present invention, the organic solvent includes but is not limited to ethyl acetate.

[0035] In a specific embodiment of the present invention, the antioxidant includes at least one of a hindered phenol antioxidant and a phosphite antioxidant.

[0036] In a specific embodiment of the present invention, the anti-ultraviolet agent includes at least one of a benzotriazole light absorber, a triazine light stabilizer and a hindered amine light stabilizer.

[0037] The second aspect of the present invention provides a method for preparing the ultra-low temperature nylon toughening agent of the first aspect of the present invention, comprising the following steps: mixing ethylene propylene diene monomer rubber, maleic anhydride and an initiator in proportion, and performing melt extrusion; A mixture of polyether polyol, antioxidant, anti-ultraviolet agent and organic solvent is added at the end of melt extrusion.

[0038] In actual operation, the above preparation method is carried out in a twin-screw extruder, and the polyether polyol, antioxidant, anti-ultraviolet agent and organic solvent are mixed in advance to obtain a mixed solution; EPDM rubber, maleic anhydride and initiator are evenly mixed in a mixing pot according to proportion, placed in an extruder hopper, melt-extruded in a twin-screw extruder, and at the end of extrusion, the mixed solution is injected into the extruder by a metering pump to participate in the reaction.

[0039] In a specific embodiment of the present invention, the extrusion temperature is 80-150° 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., 150° C., 150° C.

[0040] 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.

[0041] 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).

[0042] In actual operation, the preparation of toughened nylon includes: nylon and ultra-low temperature nylon toughening agent are extruded and granulated at 250-260°C.

[0043] Example 1 This embodiment provides an ultra-low temperature nylon toughening agent, the raw materials of which include the following components in parts by weight: 95 parts of EPDM rubber, 3 parts of maleic anhydride, 0.5 parts of initiator, 5 parts of polyether polyol, 5 parts of ethyl acetate, 0.5 parts of antioxidant and 0.5 parts of anti-ultraviolet agent.

[0044] Among them, the ethylene propylene diene monomer rubber is EPDM 3722P of Dow, USA; the maleic anhydride is of analytical grade; 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; and the anti-ultraviolet agent is anti-ultraviolet agent 770.

[0045] The preparation method of the ultra-low temperature nylon toughening agent of this embodiment comprises the following steps: (1) Mix and dissolve polyether polyol, ethyl acetate, antioxidant and anti-ultraviolet agent to obtain a mixed solution.

[0046] (2) Ethylene propylene diene monomer rubber, maleic anhydride and initiator are uniformly mixed in a mixing pot according to a certain proportion, the mixed materials are placed in a hopper of a twin-screw extruder, melt-extruded in the twin-screw extruder, and at the end of extrusion, the mixed solution of step (1) is injected into the extruder by a metering pump 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, 150°C, and 150°C, respectively.

[0047] Example 2 This example refers to the ultra-low temperature nylon toughening agent and preparation method thereof of Example 1, the only difference being that the amount of polyether polyol used is different.

[0048] The amount of the polyether polyol used in this embodiment is 3 parts by weight, and the rest is the same as that in Embodiment 1.

[0049] Example 3 This example refers to the ultra-low temperature nylon toughening agent and preparation method thereof of Example 1, the only difference being that the amount of maleic anhydride used is different.

[0050] The dosage of maleic anhydride in this embodiment is 2 parts by weight, and the rest is the same as that in Embodiment 1.

[0051] Example 4 This embodiment refers to the ultra-low temperature nylon toughening agent and preparation method thereof of Example 1, the only difference being that the amounts of maleic anhydride and polyether polyol used are different.

[0052] The dosage of maleic anhydride in this embodiment is 2 parts, the dosage of polyether polyol is 3 parts, and the rest is the same as that in Example 1.

[0053] Example 5 This embodiment refers to the ultra-low temperature nylon toughening agent and preparation method thereof of Example 1, the only difference being that the amounts of maleic anhydride and polyether polyol used are different.

[0054] The amount of maleic anhydride used in this embodiment is 3 parts, the amount of polyether polyol used is 2 parts, and the rest is the same as in Example 1.

[0055] Example 6 This embodiment refers to the ultra-low temperature nylon toughening agent and preparation method thereof of Example 1, the only difference being that the amounts of maleic anhydride and polyether polyol used are different.

[0056] The dosage of maleic anhydride in this embodiment is 1 part, the dosage of polyether polyol is 4 parts, and the rest is the same as that in Example 1.

[0057] Comparative Example 1 Comparative Example 1 refers to the ultra-low temperature nylon toughening agent and preparation method thereof of Example 1, except that the type of polyether polyol is different.

[0058] The polyether polyol of Comparative Example 1 is a polyether diol (model DL-3000D) having a number average molecular weight of 3000 to 5000.

[0059] Comparative Example 2 Comparative Example 2 refers to the ultra-low temperature nylon toughening agent and preparation method thereof of Example 1, except that the type of polyether polyol is different.

[0060] The polyether polyol of Comparative Example 2 is a polyether triol (model: TO330) having a number average molecular weight lower than 3,000.

[0061] Comparative Example 3 Comparative Example 3 refers to the ultra-low temperature nylon toughening agent and its preparation method of Example 1, except that: the raw materials of Comparative Example 3 do not include polyether polyol, ethyl acetate, antioxidant and anti-ultraviolet agent; and in the preparation, there is no need to add the mixed solution at the end through a metering pump. The rest is the same as Example 1.

[0062] Comparative Example 4 Comparative Example 4 refers to the ultra-low temperature nylon toughening agent and preparation method thereof of Example 1, except that: the raw materials of Comparative Example 4 do not include maleic anhydride and initiator; and in the preparation, maleic anhydride and initiator do not need to be added in step (2). The rest is the same as Example 1.

[0063] Comparative Example 5 Comparative Example 5 refers to the ultra-low temperature nylon toughening agent and preparation method thereof of Example 1, except that the amount of polyether polyol used is different.

[0064] The amount of the polyether polyol used in Comparative Example 5 is 8 parts, and the rest is the same as that in Example 1.

[0065] Experimental example The toughening agents prepared in different embodiments and comparative examples were made into test specimens and subjected to the following tests. The test results are shown in Table 1.

[0066] Preparation of the sample: Nylon 6 and toughening agent were weighed at a mass ratio of 100:15 and mixed evenly in a high-speed mixer, and then extruded and granulated at 250°C and conventionally injected to form a standard sample. The injection molding process was set as follows: injection temperature was 200°C and injection pressure was 17 MPa.

[0067] Table 1 Test results of different toughening agents

[0068] From the above test results, it can be seen that the present invention grafts maleic anhydride on EPDM rubber, introduces polyether polyol with excellent low-temperature toughness, and uses the reaction of maleic anhydride and polyether polyol to graft polyether polyol into the molecular chain of EPDM rubber, fully dissipates energy under external force, thereby significantly improving the toughness of the material. The impact strength of the toughened nylon prepared by the ultra-low temperature nylon toughening agent of the present invention is significantly improved at ultra-low temperature (-40°C).

[0069] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, 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 3000-5000.

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 method for preparing the ultra-low temperature nylon toughening agent according to any one of claims 1 to 7, characterized in that: The steps include: EPDM rubber, maleic anhydride and initiator are mixed in proportion and melt-extruded; A mixture of polyether polyol, antioxidant, anti-ultraviolet agent and organic solvent is added to the end of the melt extrusion.

9. The preparation method according to claim 8, characterized in that: The temperature of the melt extrusion is 80-150°C.

10. Toughened nylon, characterized in that: The invention comprises nylon and the ultra-low temperature nylon toughening agent described in any one of claims 1 to 7 or the ultra-low temperature nylon toughening agent prepared by the preparation method described in any one of claims 8 to 9.

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