CN108129757B

CN108129757B - Ultralow temperature-resistant toughening material for injection molding grade nylon and preparation method thereof

Info

Publication number: CN108129757B
Application number: CN201711405134.1A
Authority: CN
Inventors: 吕通建
Original assignee: SHENYANG KETONG PLASTIC CO Ltd
Current assignee: SHENYANG KETONG PLASTIC CO Ltd
Priority date: 2017-12-22
Filing date: 2017-12-22
Publication date: 2021-03-23
Anticipated expiration: 2037-12-22
Also published as: CN108129757A

Abstract

The invention belongs to the field of high polymer materials, and particularly relates to an ultralow temperature resistant injection molding grade nylon toughening material and a preparation method thereof. The raw materials are as follows according to the weight portion: 70-80 parts of ethylene propylene diene monomer, 20-30 parts of ethylene octene copolymer, 5-10 parts of dibenzoyl peroxide, 0.5-2 parts of maleic anhydride, 11-5 parts of KT-11, 1-5 parts of carbon nano tube, 0.05-0.3 part of solid initiator, 0.05-0.3 part of liquid initiator, 0.1-0.5 part of heat stabilizer, 0.1-0.3 part of antioxidant and 610-20 parts of nylon. The nylon toughening agent prepared by the invention belongs to an injection molding grade toughening agent, so that the step of toughening nylon by the toughening agent through reaction extrusion is omitted, and the production cost is effectively saved; and secondly, the invention can be applied at the ambient temperature of minus 50 ℃, effectively improves the low-temperature resistance of the toughened nylon and improves the notch impact strength of the toughened nylon.

Description

Ultralow temperature-resistant toughening material for injection molding grade nylon and preparation method thereof

Technical Field

The invention belongs to the field of high polymer materials, and particularly relates to an ultralow temperature resistant injection molding grade nylon toughening material and a preparation method thereof.

Background

Nylon resin, which is the resin developed by DuPont for preparing fibers at first, realizes mass production in 1939; in the 50 th of the 20 th century, injection molded products are developed and produced to replace metals to meet the requirements of light weight and cost reduction of downstream industrial products. The nylon has the advantages of high mechanical strength, good toughness, outstanding fatigue resistance, good corrosion resistance and aging resistance, and the prepared sample piece has the advantages of light weight, easy dyeing, easy molding and the like; therefore, nylon is widely used to replace metals such as copper to manufacture bearings, gears, pump blades and other parts in the industries of machinery, chemical engineering, instruments, automobiles and the like, and because polyamide has high strength after being melt-spun into filaments, the nylon can be used as synthetic fibers and can be used as medical sutures. However, nylon also has significant disadvantages: poor water absorption, poor product dimensional stability, poor antistatic force, poor low temperature resistance and the like, wherein the poor low temperature resistance seriously restricts the use of nylon in a low temperature environment. For example, the nylon cable tie is easy to stress crack under low temperature environment; the nylon pipeline is easy to crack at low temperature, and the like. In recent years, much attention has been paid to a large number of scholars to solve the problem of the above-mentioned defects of nylon, and particularly, the study on the improvement of the low-temperature resistance of nylon materials is important, and the nylon tie material can be used for solving the problem that the nylon tie material is easy to stress crack in a low-temperature environment.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides an ultralow temperature resistant injection molding grade nylon toughening material and a preparation method thereof. The nylon toughening agent prepared by the invention belongs to an injection molding grade toughening agent, so that the step of toughening nylon by the toughening agent through reaction extrusion is omitted, and the production cost is effectively saved; and secondly, the invention can be applied at the ambient temperature of minus 50 ℃, effectively improves the low-temperature resistance of the toughened nylon and improves the notch impact strength of the toughened nylon.

In order to achieve the purpose, the ultralow temperature resistant injection molding grade nylon toughening material provided by the invention comprises the following raw materials in parts by weight: 70-80 parts of ethylene propylene diene monomer, 20-30 parts of ethylene octene copolymer, 5-10 parts of dibenzoyl peroxide, 0.5-2 parts of maleic anhydride, 11-5 parts of KT-11, 1-5 parts of carbon nano tube, 0.05-0.3 part of solid initiator, 0.05-0.3 part of liquid initiator, 0.1-0.5 part of heat stabilizer, 0.1-0.3 part of antioxidant and 610-20 parts of nylon.

Preferably, the raw materials are as follows according to the weight portion: 70-80 parts of ethylene propylene diene monomer, 20-30 parts of ethylene octene copolymer, 5-10 parts of dibenzoyl peroxide, 1-1.5 parts of maleic anhydride, 12-4 parts of KT-4, 1-5 parts of carbon nano tube, 0.15-0.25 part of solid initiator, 0.1-0.2 part of liquid initiator, 0.3-0.5 part of heat stabilizer, 0.2-0.3 part of antioxidant and 610-20 parts of nylon.

Preferably, the solid initiator is dicumyl peroxide (DCP).

Preferably, the liquid initiator is a bis-penta-curing agent.

Preferably, the heat stabilizer is zinc stearate, and can be used as a lubricant.

Preferably, the KT-1 is maleic anhydride grafted polypropylene manufactured by the company.

Preferably, the antioxidant is a hindered phenol antioxidant 1010 and 1098 mixed antioxidant, and the weight ratio of 1010 to 1098 is 1: 2.

In order to achieve the purpose, the preparation method of the ultralow temperature resistant injection molding grade nylon toughening material provided by the invention specifically comprises the following steps.

Step 1, blending ethylene propylene diene monomer and ethylene octene copolymer for 3-5min at the temperature of 170-180 ℃, adding dibenzoyl peroxide for reaction for 7-10min, and obtaining the EPDM/POE thermoplastic elastomer.

Step 2, a preparation process of KT-1: putting 100 parts of polypropylene, 0.7-0.9 part of maleic anhydride, 0.1-0.3 part of solid initiator, 0.3-0 part of heat stabilizer and 0.2-0.3 part of antioxidant into a high-speed mixer, uniformly mixing for 5min, and extruding by using double screws to prepare KT-1; the extrusion temperature was set as: the first zone 165-; the residence time of each zone is 6-8 seconds; the number of revolutions of the main machine is as follows: 450-550 r/min; the initiator is dicumyl peroxide (DCP); the heat stabilizer is zinc stearate; the antioxidant is hindered phenol antioxidant 1010.

And 3, mixing the EPDM/POE thermoplastic elastomer, the maleic anhydride, the KT-1, the carbon nano tube, the solid initiator, the heat stabilizer and the antioxidant according to the weight ratio, putting the mixture into a high-speed mixer, setting the mixing time to be 5min, and uniformly mixing the raw materials.

And 4, putting the uniformly mixed materials into a conventional double-screw extruder in the field, wherein the extrusion temperature is set as follows: the first zone is 175-185 ℃, the second zone is 180-190 ℃, the third zone is 185-195 ℃, the fourth zone is 230-240 ℃, the fifth zone is 235-245 ℃, the sixth zone is 195-205 ℃, the seventh zone is 190-200 ℃, the eighth zone is 185-195 ℃, the ninth zone is 180-190 ℃ and the head is 195-205 ℃; the residence time of each zone is 6-8 seconds; the number of revolutions of the main machine is as follows: 500-600 r/min; when the temperature of the double-screw extruder meets the production requirement, injecting a liquid initiator into a second barrel of the extruder close to the blanking device through a liquid pump; the nylon 6 is added at a third section of a cylinder body of the extruder, which is close to the blanking device, in a side feeding mode, wherein the cylinder body is a device for wrapping the screw in the double-screw extruder.

Step 5, carrying out underwater granulation, dehydrator and vibrating screen on the material extruded by the extruder head to obtain particles; drying to obtain the ultralow temperature resistant nylon toughening agent; wherein: controlling the grain size of the cut grains to be 3-4 mm; the water content of the particles after dehydration treatment by the dehydrator is controlled below 0.3 percent; the drying temperature is set to 50-60 ℃ and the drying time is set to 0.5 h.

The invention provides an ultralow temperature resistant injection molding grade nylon, which is prepared by the following steps (by weight): adding 15-20 parts of the toughening agent for nylon into 80-85 parts of nylon, mixing with 0.1-0.3 part of nylon nucleating agent and 0.1-0.3 part of carboxyl nitrile rubber, and directly injecting; the injection molding process comprises the following steps: the injection molding temperature is 230-250 ℃, and the injection molding pressure is set as follows: 46-48MPa, injection speed: 65-75 cm/s.

The nucleating agent is ULTRA-DN Italian pril nylon nucleating agent.

The invention has remarkable effect.

The invention selects maleic anhydride grafted EPDM/POE elastomer as the ultralow temperature resistant nylon toughening agent and has the advantages that: ethylene propylene diene monomer has various varieties and has the advantages of low density, high filling property, aging resistance, corrosion resistance and the like; in addition, when the propylene content in the ethylene propylene diene monomer is higher, the ethylene propylene diene monomer has better low-temperature resistance. The invention adopts EPDM/POE thermoplastic elastomer, and the ethylene-octene copolymer is added, so that the inherent characteristics of the ethylene-propylene-diene monomer rubber are maintained, and the ethylene-propylene-diene monomer rubber has obvious process performances of injection, extrusion, blow molding and calendaring molding of thermoplastic plastics; due to the addition of dibenzoyl peroxide, the ethylene propylene diene monomer and the ethylene octene copolymer can react better to form an EPDM/POE elastomer; the self-made KT-1 product which is maleic anhydride grafted polypropylene and has better fluidity is added into the EPDM/POE thermoplastic elastomer, so that the fluidity of the EPDM/POE thermoplastic elastomer can be effectively improved, and the toughened nylon injection molding grade toughening agent is prepared; the carbon nano tube is added, so that the toughening material can form a net-shaped dispersion structure when being added into a nylon product, the overall strength of the material is improved, when the toughening material interacts with the EPDM/POE elastomer, and when the nylon material is impacted at a low temperature, heat generated by deformation can be rapidly dispersed to other parts, namely, the phase change improves the temperature of the material when the material is impacted again, and further the impact strength of the material in a low-temperature environment is improved; the invention adopts two initiators, wherein dicumyl peroxide is in powder form and can be fully contacted with maleic anhydride in an unmelted state and EPDM/POE elastomer to carry out grafting reaction in one step; the dipentavulcanizing agent is a liquid initiator and can be well mixed and reacted with the materials in the molten state, so that the dipentavulcanizing agent is injected into the second cylinder of the extruder by a liquid pump, the mixture can be more fully mixed with the EPDM/POE thermoplastic elastomer and the maleic anhydride in the molten state in the shearing process of the extruder, the maleic anhydride can be more fully subjected to grafting reaction with the EPDM/POE elastomer, the residue of the maleic anhydride is reduced, and the grafting rate of the toughening agent is improved; according to the invention, a certain amount of nylon 6 is added at the third cylinder body by a side feeding method, so that the melting point of the maleic anhydride grafted EPDM/POE elastomer is effectively improved, and the phenomenon that the maleic anhydride grafted EPDM/POE elastomer is stuck together and caked in the subsequent heating and drying processes is prevented; in addition, the addition of the nylon 6 can effectively improve the flow property of the toughening agent, increase the melt index of the toughening agent, enable the toughening agent to be better dispersed during subsequent blending and toughening with the nylon, and control the addition of the nylon 6, so that the dispersing effect of the toughening agent can reach the high temperature in an extruder and the dispersing degree during melt blending, and effectively improve the notch impact strength of the toughened nylon material at the temperature of minus 50 ℃; the reaction selects two hindered phenol antioxidants to be mixed for use, the antioxidant 1010 is mainly used for preventing the maleic anhydride grafted ethylene propylene diene monomer toughening agent from aging, the antioxidant 1098 is mainly used for inhibiting the oxidation reaction of polyamide, and the antioxidant is mainly used for preventing the ultralow temperature resistant toughening nylon from aging and prolonging the service time of the ultralow temperature resistant nylon for 3-5 years.

The invention mainly adopts the technologies of dynamic vulcanization technology, melt extrusion grafting technology and underwater grain cutting technology, has low cost required by equipment investment and low production cost, and can carry out continuous operation. The melt extrusion grafting technology mainly comprises the steps of raising the temperature to enable materials to be in a molten state, and enabling the materials to be in full contact through the in-phase rotation of double screws to perform reaction. Inevitably, side reactions occur during this reaction, so comparative experimental analysis is required for process conditions and initiator usage, among other factors. The initiator adopts dicumyl peroxide and a bis-dipenta initiator, the heat stabilizer and the lubricant are zinc stearate, and the mixed antioxidant is adopted. Materials extruded by the extruder are prepared into particles by an underwater pelletizing technology, and the toughening agent has certain viscosity, so that strip phenomenon is easy to occur when bracing is used for cutting, and the underwater pelletizing technology can effectively avoid the phenomenon.

Detailed Description

The present invention will be further described with reference to the following specific examples; the invention is further verified by changing the dosage of solid initiator, liquid initiator, maleic anhydride, KT-1, heat stabilizer and the like, and the addition modes of extrusion screw combination, initiator and nylon PA 6.

Example 1.

The effect of the amount of solid initiator on the toughening agent was investigated.

Firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.7 part of maleic anhydride, 0.1 part of DCP, 0.3 part of zinc stearate and 0.2 part of 1010 parts of DCP are put into a high-speed mixer to be uniformly mixed for 5min, and the mixture is extruded by a double screw to prepare KT-1. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; preparing KT-1; then, taking 85 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 2.5 parts of KT-1, 3 parts of carbon nano tubes, 0.4 part of heat stabilizer and 0.2 part of mixed antioxidant, adding a solid initiator according to the following table 1, uniformly mixing in a high-speed mixer, and putting into a double-screw extruder for extrusion;

the extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min. Injecting 0.15 part of a Bitwenty-five vulcanizing agent into a second section of barrel of the extruder by a liquid pump, and adding 15 parts of nylon 6 into a third section of barrel of the extruder in a side feeding manner; underwater granulating the material extruded by the extruder head, and performing dewatering and vibrating screen to obtain particles (3-4 mm); the obtained particles were dried (temperature set at 60 ℃) to prepare an ultra-low temperature resistant nylon toughening agent, and the research results are shown in table 1.

Table 1: impact of different solid initiator contents on the toughening agent.

The analysis of the above results can result in: when the using amount of the solid initiator is 0.15-0.25 part, the grafting ratio of the obtained toughening agent is the highest, so that the grafting ratio range of the obtained toughening agent is as follows: 0.70-0.85; the range of the molten finger is as follows: 2.2-2.5; therefore, the solid initiator is preferably used in an amount of 0.15 to 0.25 part by weight in the present invention.

Example 2.

Study on the Effect of the amount of liquid initiator on the toughening agent。

Firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.9 part of maleic anhydride, 0.3 part of DCP, 0.5 part of zinc stearate and 0.3 part of 1010 parts of zinc stearate are placed in a high-speed mixer to be uniformly mixed for 5min, and the KT-1 is prepared by twin-screw extrusion. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared. Then, taking 85 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 2.5 parts of KT-1, 3 parts of carbon nano tubes, 0.25 part of solid initiator, 0.4 part of heat stabilizer and 0.2 part of mixed antioxidant, putting the mixture into a high-speed mixer, uniformly mixing, and putting the mixture into a double-screw extruder for extrusion; the extrusion temperature was set as: the extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; referring to table 2 below, a liquid initiator was injected and 15 parts of nylon 6 was added by side feeding at the third barrel of the extruder; granulating the material extruded by the extruder head under water, and carrying out a dehydrator and a vibrating screen to obtain particles (3-4 mm); the obtained particles were dried (temperature set at 60 ℃) to prepare an ultra-low temperature resistant nylon toughening agent, and the research results are shown in table 2.

Table 2: the effect of different liquid initiator levels on the toughening agent.

The detection results can obtain that: the optimal dosage of the injection liquid initiator of the bis-di-penta is 0.1 to 0.2 part.

Experimental example 3.

Study on the influence of the amount of maleic anhydride on the toughening agent。

Firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.8 part of maleic anhydride, 0.25 part of DCP, 0.35 part of zinc stearate and 0.2 part of 1010 parts of zinc stearate are placed in a high-speed mixer to be uniformly mixed for 5min, and the KT-1 is prepared by twin-screw extrusion. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared. Then, 85 parts of EPDM/POE thermoplastic elastomer, 2.5 parts of KT-1, 3 parts of carbon nano tube, 0.25 part of solid initiator, 0.4 part of heat stabilizer and 0.2 part of mixed antioxidant are taken, maleic anhydride is added according to the following table 3, the mixture is placed in a high-speed mixer to be mixed uniformly, and the mixture is put into a double-screw extruder for extrusion. The extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; 0.15 part of the bis-di-penta vulcanizing agent is injected into the second section of the barrel of the extruder by a liquid pump, and 15 parts of nylon 6 is added at the third section of the barrel of the extruder in a side feeding mode. Granulating the material extruded by the extruder head under water, and carrying out a dehydrator and a vibrating screen to obtain particles (3-4 mm); the obtained particles were dried (temperature set at 50 ℃) to prepare an ultra-low temperature resistant nylon toughening agent, and the research results are shown in table 3.

Table 3: the effect of different maleic anhydride contents on the toughening agent.

The analysis of the above results can result in: maleic anhydride is preferably used in an amount of 1 to 1.5 parts.

Example 4.

Research on influence of amount of KT-1 on toughening agent。

Firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.8 part of maleic anhydride, 0.1 part of DCP, 0.5 part of zinc stearate and 0.3 part of 1010 parts of zinc stearate are placed in a high-speed mixer to be uniformly mixed for 5min, and the KT-1 is prepared by twin-screw extrusion. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared. Then, taking 85 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 3 parts of carbon nano tube, 0.25 part of solid initiator, 0.4 part of heat stabilizer and 0.2 part of mixed antioxidant, adding KT-1 according to the following table 4, placing the mixture into a high-speed mixer, uniformly mixing, and putting the mixture into a double-screw extruder for extrusion; the extrusion temperature was: the extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; 0.15 part of the bis-di-penta vulcanizing agent is injected into the second section of the barrel of the extruder by a liquid pump, and 15 parts of nylon 6 is added at the third section of the barrel of the extruder in a side feeding mode. Granulating the material extruded by the extruder head under water, and carrying out a dehydrator and a vibrating screen to obtain particles (3-4 mm); the resulting particles were dried (temperature set at 55 ℃) to prepare ultra low temperature resistant nylon tougheners, the results of which are shown in table 4.

Table 4: the effect of different maleic anhydride contents on the toughening agent.

The analysis of the above results can result in: the preferred amount of KT-1 is 2-4 parts.

Example 5.

Research on influence of dosage of heat stabilizer on toughening agent。

Firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.7 part of maleic anhydride, 0.3 part of DCP, 0.4 part of zinc stearate and 0.25 part of 1010 parts of zinc stearate are placed in a high-speed mixer to be uniformly mixed for 5min, and the KT-1 is prepared by twin-screw extrusion. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared. Then, 85 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 2.5 parts of KT-1, 3 parts of carbon nano tubes and 0.25 part of solid initiator are taken, and the following table 5 is referred to, added with a heat stabilizer and 0.2 part of antioxidant, placed in a high-speed mixer to be mixed uniformly, and put into a double-screw extruder for extrusion. The extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; 0.15 part of the bis-di-penta vulcanizing agent is injected into the second section of the barrel of the extruder by a liquid pump, and 15 parts of nylon 6 is added at the third section of the barrel of the extruder in a side feeding mode. Granulating the material extruded by the extruder head under water, and carrying out a dehydrator and a vibrating screen to obtain particles (3-4 mm); the resulting granules were subjected to a drying treatment (temperature set at 50 ℃). The ultra low temperature resistant nylon toughener was prepared and the results are shown in table 5.

Table 5: the influence of the content of different heat stabilizers on the toughening agent.

The analysis of the above results can result in: when zinc stearate is used in a preferred amount of 0.3 to 0.5 parts.

Example 6.

Study on the influence of the amount of the mixed antioxidant on the toughening agent。

Firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.75 part of maleic anhydride, 0.2 part of DCP, 0.35 part of zinc stearate and 0.3 part of 1010 parts of zinc stearate are uniformly mixed in a high-speed mixer for 5min, and the mixture is extruded by a double screw to prepare KT-1. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared. Then, 85 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 2.5 parts of KT-1, 3 parts of carbon nano tubes, 0.25 part of solid initiator and 0.4 part of heat stabilizer are taken, mixed with antioxidant according to the table 6, placed in a high-speed mixer to be mixed uniformly, and put into a double-screw extruder for extrusion. The extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; 0.15 part of the bis-di-penta vulcanizing agent is injected into the second section of the barrel of the extruder by a liquid pump, and 15 parts of nylon 6 is added at the third section of the barrel of the extruder in a side feeding mode. Granulating the material extruded by the extruder head under water, and carrying out a dehydrator and a vibrating screen to obtain particles (3-4 mm); the resulting particles were dried (temperature set at 55 ℃) to prepare ultra low temperature resistant nylon tougheners, the results of which are shown in table 6.

Table 6: the effect of the antioxidant content on the appearance of the toughening agent.

As a result, it is found that the amount of the antioxidant is preferably 0.2 to 0.3 part.

Experimental example 7.

Study of the Effect of screw combination on toughening Agents。

The research of the screw combination is the arrangement mode of the thread blocks in the screw in the extruder, and when the degree of the thread blocks at the shearing part of the screw is larger, the shearing capability of the screw is stronger, so that the materials can be mixed more uniformly. When the screw is strong in shearing, a thread block with the degree of 90 degrees is adopted; when the screw rod is sheared, a thread block with the degree of 60 degrees is adopted; when the shearing of the screw rod is weak, a thread block with the degree of 45 degrees is adopted.

Firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.9 part of maleic anhydride, 0.1 part of DCP, 0.3 part of hot zinc stearate and 0.3 part of 1010 parts of hot zinc stearate are uniformly mixed in a high-speed mixer for 5min, and the mixture is extruded by a double screw to prepare KT-1. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared. Then, 85 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 2.5 parts of KT-1, 3 parts of carbon nano tubes, 0.25 part of solid initiator, 0.4 part of heat stabilizer and 0.2 part of mixed antioxidant are put into a high-speed mixer to be mixed uniformly and put into a double-screw extruder for extrusion. The experiments were performed according to the screw combinations of table 7, respectively, with the extrusion temperatures set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; 0.15 part of the bis-di-penta vulcanizing agent is injected into the second section of the barrel of the extruder by a liquid pump, and 15 parts of nylon 6 is added at the third section of the barrel of the extruder in a side feeding mode. Granulating the material extruded by the extruder head under water, and carrying out a dehydrator and a vibrating screen to obtain particles (3-4 mm); the resulting particles were dried (temperature set at 55 ℃) to prepare ultra low temperature resistant nylon tougheners, the results of which are shown in table 7.

Table 7: impact of screw combinations of different strengths on the toughening agent.

The analysis of the above results can result in: the screw combination is strong, and the prepared toughening agent has a good effect.

Experimental example 8.

Study on the influence of the initiator addition mode on the toughening agent。

Firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.9 part of maleic anhydride, 0.1 part of DCP, 0.35 part of zinc stearate and 0.3 part of 1010 parts of zinc stearate are placed in a high-speed mixer to be uniformly mixed for 5min, and the KT-1 is prepared by twin-screw extrusion. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared. Then, 85 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 2.5 parts of KT-1, 3 parts of carbon nano tubes, 0.25 part of solid initiator, 0.4 part of heat stabilizer and 0.2 part of mixed antioxidant are put into a high-speed mixer to be uniformly mixed and are put into a double-screw extruder for extrusion. The extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; 0.25 parts of solid initiator and 0.15 parts of bis-penta initiator were added as in Table 8, and 15 parts of nylon 6 were added by side feeding at the third barrel of the extruder. Granulating the material extruded by the extruder head under water, and carrying out a dehydrator and a vibrating screen to obtain particles (3-4 mm); the resulting particles were dried (temperature set at 55 ℃) to prepare ultra low temperature resistant nylon tougheners, the results of which are shown in table 8.

Table 8: influence of the addition mode of the initiator on the appearance of the toughening agent.

The results can be analyzed, and the solid initiator is preferably added directly during mixing; the liquid initiator is preferably added at the second barrel.

Example 9.

Research on the influence of the addition mode of the nylon PA6 on the toughening agent。

Firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.9 part of maleic anhydride, 0.1 part of DCP, 0.35 part of zinc stearate and 0.3 part of 1010 parts of zinc stearate are placed in a high-speed mixer to be uniformly mixed for 5min, and the KT-1 is prepared by twin-screw extrusion. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared. Then, 85 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 2.5 parts of KT-1, 3 parts of carbon nano tubes, 0.25 part of solid initiator and 0.4 part of heat stabilizer are placed in a high-speed mixer to be mixed uniformly and are put into a double-screw extruder for extrusion. The extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; injecting 0.15 part of a Bidawu vulcanizing agent into a second section cylinder of the extruder by a liquid pump, adding 15 parts of nylon PA6 according to the mode shown in the table 9, and carrying out underwater grain cutting, a dehydrator and a vibrating screen on the material extruded by the extruder head to obtain particles (3-4 mm); the resulting particles were dried (temperature set at 55 ℃ C.) to prepare ultra low temperature resistant nylon tougheners, the results of which are shown in Table 9.

Table 9: the addition mode of nylon 6 has influence on the appearance of the toughening agent.

The above results can be analyzed and it is preferred that nylon PA6 be added by side feeding 15 parts of nylon 6 at the third barrel of the extruder.

Example 10.

The method for preparing nylon by using the toughening agent disclosed by the invention is as follows.

Step 1, firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain an EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.9 part of maleic anhydride, 0.3 part of DCP, 0.5 part of zinc stearate and 0.3 part of 1010 parts of zinc stearate are placed in a high-speed mixer to be uniformly mixed for 5min, and the KT-1 is prepared by twin-screw extrusion. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared. Then, 80 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 2.5 parts of KT-1, 3 parts of carbon nano tubes, 0.25 part of solid initiator, 0.4 part of heat stabilizer and 0.2 part of mixed antioxidant are placed in a high-speed mixer to be mixed uniformly.

Step 2, putting the mixed material into a double-screw extruder, wherein the extrusion temperature is set as follows: the extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; 0.15 part of the initiator bis-di-penta is injected into the second section of the barrel of the extruder by a liquid pump, and 20 parts of nylon 6 is added at the third section of the barrel of the extruder in a side feeding mode. Carrying out strip drawing, water cooling and grain cutting on the material extruded by the extruder head to obtain particles; and drying the obtained particles (the temperature is set to 55 ℃) to prepare the ultralow temperature resistant nylon toughening agent.

Step 3, mixing 85 parts of nylon, 15 parts of toughening agent, 0.2 part of nylon nucleating agent and 0.2 part of carboxyl nitrile rubber according to the weight ratio, and uniformly mixing the materials by a high-speed mixer; and putting the mixture into an injection molding machine to be directly injection molded into a standard sample strip. The injection molding process comprises the following steps: the injection temperature is 240 ℃, and the injection pressure is set as follows: 46MPa, injection speed: 70 cm/s.

Example 11.

Step 1, firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain an EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.9 part of maleic anhydride, 0.2 part of DCP, 0.3 part of zinc stearate and 0.3 part of 1010 parts of zinc stearate are placed in a high-speed mixer to be uniformly mixed for 5min, and the KT-1 is prepared by twin-screw extrusion. The extrusion temperature was set as: 170 ℃ in the first area, 175 ℃ in the second area, 180 ℃ in the third area, 185 ℃ in the fourth area, 190 ℃ in the fifth area, 190 ℃ in the sixth area, 185 ℃ in the seventh area, 180 ℃ in the eighth area, 175 ℃ in the ninth area and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared.

And 2, taking 85 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 2.5 parts of KT-1, 3 parts of carbon nano tubes, 0.25 part of solid initiator, 0.4 part of heat stabilizer and 0.2 part of mixed antioxidant, putting the mixture into a high-speed mixer, uniformly mixing, and putting the mixture into a double-screw extruder for extrusion.

Step 3, putting the mixed material into a double-screw extruder, wherein the extrusion temperature is set as follows: the extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; 0.15 part of the initiator bis-di-penta is injected into the second section of the barrel of the extruder by a liquid pump, and 15 parts of nylon 6 is added at the third section of the barrel of the extruder in a side feeding mode. Carrying out strip drawing, water cooling and grain cutting on the material extruded by the extruder head to obtain particles; and drying the obtained particles (the temperature is set to 55 ℃) to prepare the ultralow temperature resistant nylon toughening agent.

Step 4, mixing 80 parts of nylon, 20 parts of toughening agent, 0.2 part of nylon nucleating agent and 0.2 part of carboxyl nitrile rubber according to the weight ratio, and uniformly mixing the materials by a high-speed mixer; and putting the mixture into an injection molding machine to be directly injection molded into a standard sample strip. The injection molding process comprises the following steps: the injection temperature is 240 ℃, and the injection pressure is set as follows: 46MPa, injection speed: 70 cm/s.

Example 12.

Step 1, firstly, blending 75 parts of ethylene propylene diene monomer and 25 parts of ethylene octene copolymer for 5min at 170 ℃, adding 7 parts of dibenzoyl peroxide, and reacting for 7min to obtain an EPDM/POE thermoplastic elastomer; 100 parts of polypropylene, 0.8 part of maleic anhydride, 0.2 part of DCP, 0.5 part of zinc stearate and 0.25 part of 1010 parts of zinc stearate are placed in a high-speed mixer to be uniformly mixed for 5min, and the KT-1 is prepared by twin-screw extrusion. The extrusion temperature is set as 170 ℃ in the first zone, 175 ℃ in the second zone, 180 ℃ in the third zone, 185 ℃ in the fourth zone, 190 ℃ in the fifth zone, 190 ℃ in the sixth zone, 185 ℃ in the seventh zone, 180 ℃ in the eighth zone, 175 ℃ in the ninth zone and 190 ℃ in the head; residence time per zone was 7 seconds; the number of revolutions of the main machine is as follows: 500 r/min; KT-1 is prepared.

And 2, taking 90 parts of EPDM/POE thermoplastic elastomer, 1.5 parts of maleic anhydride, 2.5 parts of KT-1, 3 parts of carbon nano tubes, 0.25 part of solid initiator, 0.4 part of heat stabilizer and 0.2 part of mixed antioxidant, putting the mixture into a high-speed mixer, uniformly mixing, and putting the mixture into a double-screw extruder for extrusion.

Step 3, putting the mixed material into a double-screw extruder, wherein the extrusion temperature is set as follows: the extrusion temperature was set as: the first zone is 180 ℃, the second zone is 185 ℃, the third zone is 190 ℃, the fourth zone is 235 ℃, the fifth zone is 240 ℃, the sixth zone is 200 ℃, the seventh zone is 195 ℃, the eighth zone is 190 ℃, the ninth zone is 185 ℃, and the head is 200 ℃; the residence time per zone was 6 seconds; the number of revolutions of the main machine is as follows: 550 r/min; 0.15 part of the initiator bis-di-penta is injected into the second section of the barrel of the extruder by a liquid pump, and 10 parts of nylon 6 is added at the third section of the barrel of the extruder in a side feeding mode. Carrying out strip drawing, water cooling and grain cutting on the material extruded by the extruder head to obtain particles; and drying the obtained particles (the temperature is set to 55 ℃) to prepare the ultralow temperature resistant nylon toughening agent.

Step 4, mixing 82 parts of nylon, 18 parts of toughening agent, 0.2 part of nylon nucleating agent and 0.2 part of carboxyl nitrile rubber according to the weight ratio, and uniformly mixing the materials by a high-speed mixer; and putting the mixture into an injection molding machine to be directly injection molded into a standard sample strip. The injection molding process comprises the following steps: the injection temperature is 240 ℃, and the injection pressure is set as follows: 46MPa, injection speed: 70 cm/s.

The test method comprises the following steps:the notch impact strength of the toughened nylon material at minus 50 ℃ is observed by adding different parts of the nylon toughening agent. 15 parts, 16.5 parts, 18 parts and 20 parts of the toughening agents obtained in the examples 8 to 10 and corresponding 85 parts, 83.5 parts, 82 parts and 80 parts of nylon are respectively put into a high-speed mixer, the toughening agents and the nylon are uniformly mixed and directly put into an injection molding machine to be molded into standard sample pieces, and the prepared nylon standard sample strips are subjected to performance detection, wherein the results are shown in Table 10.

Table 10: and (3) comparing the notch impact strength of the toughened nylon at the temperature of minus 50 ℃.

From the above detection results, it can be seen that: compared with the low-temperature impact property of pure PA6, the nylon toughening agent can effectively improve the toughening effect of nylon at the temperature of minus 50 ℃ and improve the notch impact strength by 1 to 3 times. The effect of example 11 was most pronounced.

Example 13.

The ultra-low temperature resistant injection molding grade nylon toughening material comprises the following raw materials in parts by weight: 70 parts of ethylene propylene diene monomer, 30 parts of ethylene octene copolymer, 10 parts of dibenzoyl peroxide, 0.5 part of maleic anhydride, KT-11 parts, 1 part of carbon nano tube, 0.3 part of solid initiator, 0.05 part of liquid initiator, 0.1 part of heat stabilizer, 0.3 part of antioxidant and 610 parts of nylon.

Example 14.

The ultra-low temperature resistant injection molding grade nylon toughening material comprises the following raw materials in parts by weight: 80 parts of ethylene propylene diene monomer, 20 parts of ethylene octene copolymer, 5 parts of dibenzoyl peroxide, 2 parts of maleic anhydride, KT-15 parts, 5 parts of carbon nano tube, 0.05 part of solid initiator, 0.3 part of liquid initiator, 0.5 part of heat stabilizer, 0.1 part of antioxidant and 620 parts of nylon.

Claims

1. The ultra-low temperature resistant toughening material for injection molding grade nylon is characterized by comprising the following raw materials in parts by weight: 70-80 parts of ethylene propylene diene monomer, 20-30 parts of ethylene octene copolymer, 5-10 parts of dibenzoyl peroxide, 1-1.5 parts of maleic anhydride, 12-4 parts of KT-4, 1-5 parts of carbon nano tube, 0.05-0.3 part of solid initiator, 0.1-0.2 part of liquid initiator, 0.3-0.5 part of heat stabilizer, 0.2-0.3 part of antioxidant and 610-20 parts of nylon;

the solid initiator is dicumyl peroxide (DCP);

the liquid initiator is a bis-dipenta-vulcanizing agent;

the heat stabilizer is zinc stearate and can also be used as a lubricant;

the KT-1 is maleic anhydride grafted polypropylene made by companies;

the antioxidant is a mixture of hindered phenol antioxidant 1010 and 1098, and the mixing weight ratio is 1: 2;

the preparation method of the ultralow temperature resistant toughening material for injection molding grade nylon specifically comprises the following steps:

step 1, blending ethylene propylene diene monomer and ethylene octene copolymer for 3-5min at the temperature of 170-;

step 2, a preparation process of KT-1: putting 100 parts of polypropylene, 0.7-0.9 part of maleic anhydride, 0.1-0.3 part of solid initiator, 0.3-0.5 part of heat stabilizer and 0.2-0.3 part of antioxidant into a high-speed mixer, uniformly mixing for 5min, and extruding by using double screws to prepare KT-1; the extrusion temperature was set as: the first zone 165-; the residence time of each zone is 6-8 seconds; the number of revolutions of the main machine is as follows: 450-550 r/min; the initiator is dicumyl peroxide (DCP); the heat stabilizer is zinc stearate; the antioxidant is hindered phenol antioxidant 1010;

step 3, mixing EPDM/POE thermoplastic elastomer, maleic anhydride, KT-1, carbon nano tubes, a solid initiator, a heat stabilizer and an antioxidant according to the weight ratio, placing the mixture in a high-speed mixer, setting the mixing time to be 5min, and uniformly mixing the raw materials;

and 4, putting the uniformly mixed materials into a double-screw extruder, wherein the extrusion temperature is set as follows: the first zone is 175-185 ℃, the second zone is 180-190 ℃, the third zone is 185-195 ℃, the fourth zone is 230-240 ℃, the fifth zone is 235-245 ℃, the sixth zone is 195-205 ℃, the seventh zone is 190-200 ℃, the eighth zone is 185-195 ℃, the ninth zone is 180-190 ℃ and the head is 195-205 ℃; the residence time of each zone is 6-8 seconds; the number of revolutions of the main machine is as follows: 500-600 r/min; when the temperature of the double-screw extruder meets the production requirement, injecting a liquid initiator into a second barrel of the extruder close to the blanking device through a liquid pump; nylon 6 is added at the third section of the barrel body of the extruder in a side feeding mode, wherein the barrel body is a device for wrapping the screw in the double-screw extruder;

step 5, carrying out underwater granulation, dehydrator and vibrating screen on the material extruded by the extruder head to obtain particles; drying to obtain the ultralow temperature resistant nylon toughening agent; wherein: controlling the grain size of the cut grains to be 3-4 mm; the water content of the particles after dehydration treatment by the dehydrator is controlled below 0.3 percent; setting the drying temperature to be 50-60 ℃ and the drying time to be 0.5 h;

the preparation method of the ultralow temperature resistant injection molding grade nylon toughened by the toughening material comprises the steps of adding 15-20 parts of the toughening agent into 80-85 parts of nylon, mixing with 0.1-0.3 part of the nylon nucleating agent and 0.1-0.3 part of the carboxyl nitrile rubber, and directly injecting after blending; the injection molding process comprises the following steps: the injection molding temperature is 230-250 ℃, and the injection molding pressure is set as follows: 46-48MPa, injection speed: 65-75 cm/s; the nucleating agent is ULTRA-DN Italian pril nylon nucleating agent.