Long-chain active agent for preparing toughened block MC nylon

Abstract

The invention relates to the technical field of nylon additives, and provides a long-chain active agent for preparing toughened block MC nylon, which is prepared from the following raw materials in parts by weight: 15 to 25 parts of caprolactam, 50 to 60 parts of polytetrahydrofuran ether glycol and 18 to 24 parts of isocyanate. The functionality of the isocyanate is gt; 2. According to the technical scheme, the problem of poor toughness of MC nylon in related technologies is solved. The long-chain active agent serving as the cocatalyst can improve the toughness of the MC nylon product, solves the problem of cracking of the MC nylon product in the production, processing, transportation, installation and use processes, and has an obvious effect on the MC nylon product with the single piece being more than 500kg and the MC nylon product compounded with a steel core.

Description

Technical Field

[0001] The invention relates to the technical field of nylon additives, and in particular to a long-chain activator for preparing toughened block MC nylon. Background Art

[0002] MC nylon is made by anionic polymerization of caprolactam. Due to its molecular structure characteristics and high crystallinity, the molecular chain of MC nylon has poor mobility, and the molecular chain is tightly and regularly arranged, which hinders the relative sliding of the molecular chain under the action of external forces. Poor toughness has become its main defect. Even if MC nylon is treated with boiling water or other processes, it will still crack during post-processing or use. Especially in some mechanical parts that need to withstand frequent vibration or impact, MC nylon parts may crack or even break prematurely, unable to meet the requirements of long-term stable operation, making the parts prone to brittle fracture under external forces. At the same time, the existing MC nylon usually has a high crystallinity, which can reach 48%~50%, or even higher. Therefore, there is an urgent need for an additive that can improve the toughness of MC nylon. Summary of the invention

[0003] The invention provides a long-chain activator for preparing toughened block MC nylon, which solves the problem of poor toughness of MC nylon in the related art.

[0004] The technical solution of the present invention is as follows: The present invention provides a long-chain activator for preparing toughened block MC nylon, comprising the following raw materials in parts by weight: 15-25 parts of caprolactam, 50-60 parts of polytetramethylene glycol, and 18-24 parts of isocyanate; The functionality of the isocyanate is >2.

[0005] As a further technical solution, the isocyanate includes polymethylene polyphenyl polyisocyanate and / or triphenylmethane triisocyanate.

[0006] As a further technical solution, the molecular weight of the polytetrahydrofuran ether diol is 2000-3000.

[0007] In the present invention, the model of polytetramethylene ether glycol can be PTMG2000, PTMG3000 and the like.

[0008] As a further technical solution, when the isocyanate is polymethylene polyphenyl polyisocyanate and triphenylmethane triisocyanate, the mass ratio of the polymethylene polyphenyl polyisocyanate to the triphenylmethane triisocyanate is 1:9 to 9:1.

[0009] In the present invention, the isocyanate is a common compound of polymethylene polyphenyl polyisocyanate and triphenylmethane triisocyanate. The obtained long-chain activator is not only a co-catalyst for MC nylon, but also can form a block copolymer MC nylon main chain structure, thereby improving the toughness of MC nylon.

[0010] As a further technical solution, the mass ratio of the polymethylene polyphenyl polyisocyanate to the triphenylmethane triisocyanate is 3:2-4:1.

[0011] In the present invention, in the raw materials of the long-chain activator, the mass ratio of polymethylene polyphenyl polyisocyanate to triphenylmethane triisocyanate is 3:2-4:1, and the prepared long-chain activator ensures the main chain structure of the block copolymer MC nylon, and finally improves the toughness of the MC nylon.

[0012] As a further technical solution, the following raw materials are also included in parts by weight: 4 to 6 parts of boron nitride nanosheet composite material.

[0013] In the present invention, a boron nitride nanosheet composite material is added to the raw material of the long-chain activator. The long-chain activator ensures the main chain structure of the block copolymer MC nylon, improves the toughness of the MC nylon, and also improves the wear resistance of the MC nylon.

[0014] As a further technical solution, the preparation method of the boron nitride nanosheet composite material comprises the following steps: mixing epoxysuccinic acid and a solvent, adding boron nitride nanosheets, and drying to obtain the boron nitride nanosheet composite material; The mass ratio of the epoxysuccinic acid, the solvent and the boron nitride nanosheets is 1-3:50:20; The boron nitride nanosheet has a sheet diameter of 1-3 μm and a thickness of less than 100 nm.

[0015] In the present invention, among the raw materials of the long-chain activator, the boron nitride nanosheet composite material is prepared by using epoxysuccinic acid and boron nitride nanosheets, and has good compatibility with the organic matrix. The long-chain activator ensures the main chain structure of the block copolymer MC nylon, improves the toughness of the MC nylon, and further improves the wear resistance of the MC nylon.

[0016] The present invention also proposes a method for preparing a long-chain activator for preparing toughened block MC nylon, comprising the following steps: S1, reacting the caprolactam and isocyanate to obtain polylactam; S2. Mixing the polylactam and the remaining raw materials of the long-chain surfactant to obtain the long-chain surfactant.

[0017] As a further technical solution, the reaction temperature is 160-175°C and the reaction time is 10-15 minutes; The mixing temperature is 115-125° C. and the mixing time is 8-9 hours.

[0018] In the present invention, caprolactam and polytetrahydrofuran ether diol are both subjected to vacuum dehydration treatment before preparing the long-chain active agent.

[0019] The present invention also proposes the use of the long-chain activator for preparing toughened block MC nylon or the long-chain activator prepared by the preparation method in toughening MC nylon.

[0020] The working principle and beneficial effects of the present invention are: In the present invention, the raw materials for preparing the long-chain active agent for toughening block MC nylon are caprolactam, polytetramethylene glycol and isocyanate with functionality>2. Finally, the long-chain active agent ensures the main chain structure of the block copolymer MC nylon and improves the toughness of the MC nylon. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the following examples and comparative examples, the model of polytetramethylene ether glycol is PTMG2000.

[0023] Example 1 A long-chain active agent for preparing toughened block MC nylon comprises the following raw materials in parts by weight: 15 parts of caprolactam, 50 parts of polytetramethylene ether glycol, and 18 parts of polymethylene polyphenyl polyisocyanate; The method for preparing a long-chain activator for preparing toughened block MC nylon comprises the following steps: S1, dehydrating caprolactam at 140° C. and vacuum degree of 1.33 kPa for 10 min, cooling to 130° C., adding polymethylene polyphenyl polyisocyanate, and reacting at 160° C. for 15 min to obtain polylactam; S2. After vacuum dehydrating polytetrahydrofuran ether diol at 120° C. for 30 min, the polytetrahydrofuran ether diol was mixed with polylactam at 115° C. and 165 r / min for 9 h to obtain a long-chain active agent.

[0024] Example 2 A long-chain active agent for preparing toughened block MC nylon comprises the following raw materials in parts by weight: 25 parts of caprolactam, 60 parts of polytetramethylene ether glycol, and 24 parts of polymethylene polyphenyl polyisocyanate; The method for preparing a long-chain activator for preparing toughened block MC nylon comprises the following steps: S1, dehydrating caprolactam at 140° C. and vacuum degree of 1.33 kPa for 10 min, cooling to 130° C., adding polymethylene polyphenyl polyisocyanate, and reacting at 175° C. for 10 min to obtain polylactam; S2. After vacuum dehydrating polytetrahydrofuran ether diol at 130° C. for 20 min, the polytetrahydrofuran ether diol was mixed with polylactam at 125° C. and 165 r / min for 8 h to obtain a long-chain active agent.

[0025] Example 3 A long-chain active agent for preparing toughened block MC nylon comprises the following raw materials in parts by weight: 20 parts of caprolactam, 58 parts of polytetramethylene ether glycol, and 22 parts of polymethylene polyphenyl polyisocyanate; The method for preparing a long-chain activator for preparing toughened block MC nylon comprises the following steps: S1, dehydrating caprolactam at 140°C and vacuum degree of 1.33 kPa for 10 min, cooling to 130°C, adding polymethylene polyphenyl polyisocyanate, and reacting at 165°C for 14 min to obtain polylactam; S2. After vacuum dehydrating polytetrahydrofuran ether diol at 125° C. for 25 min, the polytetrahydrofuran ether diol was mixed with polylactam at 120° C. and 165 r / min for 8 h to obtain a long-chain active agent.

[0026] Example 4 The difference between this embodiment and embodiment 3 is that the polymethylene polyphenyl polyisocyanate is replaced by triphenylmethane triisocyanate.

[0027] Example 5 The difference between this embodiment and embodiment 3 is that one tenth of the mass of polymethylene polyphenyl polyisocyanate is replaced by an equal amount of triphenylmethane triisocyanate.

[0028] Example 6 The difference between this embodiment and embodiment 3 is that nine-tenths of the mass of polymethylene polyphenyl polyisocyanate is replaced by an equal amount of triphenylmethane triisocyanate.

[0029] Example 7 The difference between this embodiment and embodiment 3 is that two fifths of the mass of polymethylene polyphenyl polyisocyanate is replaced by an equal amount of triphenylmethane triisocyanate.

[0030] Example 8 The difference between this embodiment and embodiment 3 is that one fifth of the mass of polymethylene polyphenyl polyisocyanate is replaced by an equal amount of triphenylmethane triisocyanate.

[0031] Example 9 A long-chain active agent for preparing toughened block MC nylon comprises the following raw materials in parts by weight: 20 parts of caprolactam, 58 parts of polytetramethylene ether glycol, 17.6 parts of polymethylene polyphenyl polyisocyanate, 4.4 parts of triphenylmethane triisocyanate, and 4 parts of boron nitride nanosheet composite material; The preparation method of the composite material of epoxysuccinic acid and boron nitride nanosheets comprises the following steps: mixing epoxysuccinic acid and methanol, adding boron nitride nanosheets, and drying to obtain a boron nitride nanosheet composite material; the mass ratio of epoxysuccinic acid, methanol and boron nitride nanosheets is 3:50:20, and the average sheet diameter of the boron nitride nanosheets is 2 μm and the average thickness is 50 nm; The method for preparing a long-chain activator for preparing toughened block MC nylon comprises the following steps: S1, dehydrating caprolactam at 140°C and vacuum degree of 1.33 kPa for 10 min, cooling to 130°C, adding polymethylene polyphenyl polyisocyanate and triphenylmethane triisocyanate, and reacting at 165°C for 14 min to obtain polylactam; S2. After vacuum dehydrating polytetrahydrofuran ether diol at 125° C. for 25 min, the polytetrahydrofuran ether diol was mixed with a composite material of polylactam and boron nitride nanosheets at 120° C. and 165 r / min for 8 h to obtain a long-chain active agent.

[0032] Example 10 A long-chain active agent for preparing toughened block MC nylon comprises the following raw materials in parts by weight: 20 parts of caprolactam, 58 parts of polytetramethylene ether glycol, 17.6 parts of polymethylene polyphenyl polyisocyanate, 4.4 parts of triphenylmethane triisocyanate, and 6 parts of boron nitride nanosheet composite material; The preparation method of the composite material of epoxysuccinic acid and boron nitride nanosheets comprises the following steps: mixing epoxysuccinic acid and methanol, adding boron nitride nanosheets, and drying to obtain a boron nitride nanosheet composite material; the mass ratio of epoxysuccinic acid, methanol and boron nitride nanosheets is 1:50:20, and the average sheet diameter of the boron nitride nanosheets is 2 μm and the average thickness is 50 nm; The method for preparing a long-chain activator for preparing toughened block MC nylon comprises the following steps: S1, dehydrating caprolactam at 140°C and vacuum degree of 1.33 kPa for 10 min, cooling to 130°C, adding polymethylene polyphenyl polyisocyanate and triphenylmethane triisocyanate, and reacting at 165°C for 14 min to obtain polylactam; S2. After vacuum dehydrating polytetrahydrofuran ether diol at 125° C. for 25 min, the polytetrahydrofuran ether diol was mixed with a composite material of polylactam and boron nitride nanosheets at 120° C. and 165 r / min for 8 h to obtain a long-chain active agent.

[0033] Embodiment 11 A long-chain active agent for preparing toughened block MC nylon comprises the following raw materials in parts by weight: 20 parts of caprolactam, 58 parts of polytetramethylene ether glycol, 17.6 parts of polymethylene polyphenyl polyisocyanate, 4.4 parts of triphenylmethane triisocyanate, and 6 parts of boron nitride nanosheets; the boron nitride nanosheets have an average sheet diameter of 2 μm and an average thickness of 50 nm; The method for preparing a long-chain activator for preparing toughened block MC nylon comprises the following steps: S1, dehydrating caprolactam at 140°C and vacuum degree of 1.33 kPa for 10 min, cooling to 130°C, adding polymethylene polyphenyl polyisocyanate and triphenylmethane triisocyanate, and reacting at 165°C for 14 min to obtain polylactam; S2. After vacuum dehydrating polytetrahydrofuran ether diol at 125° C. for 25 min, the polytetrahydrofuran ether diol was mixed with polylactam and boron nitride nanosheets at 120° C. and 165 r / min for 8 h to obtain a long-chain active agent.

[0034] Comparative Example 1 The difference between this comparative example and Example 3 is that the polymethylene polyphenyl polyisocyanate is replaced by toluene diisocyanate.

[0035] Application Examples The long-chain active agents prepared in Examples 1 to 11 and Comparative Example 1 were respectively used to prepare block copolymer MC nylon according to the following two-pot reaction process: Put 100g of long-chain active agent into 700g of caprolactam, melt at below 100℃ and then introduce into tank A. Turn on the vacuum equipment and perform vacuum dehydration at 120℃ and 10mmHg; 300g of caprolactam was directly put into tank B, and dehydrated for 5 minutes under vacuum conditions of 140℃ and 10mmHg. The vacuum was released, and 2g / kg of NaOH was put into tank B, and the vacuum was quickly restarted, and dehydrated for 10 minutes under vacuum conditions of 140℃ and 10mmHg. Before mixing the two tanks, raise the temperature of tank A to 140°C. After the melt materials in tanks A and B are prepared, release the vacuum, pour the active materials in tanks A and B into the clean preheated mixing tank, and stir quickly for 10 seconds. Pour the mixture into a mold preheated to 168°C for molding, demold, and obtain MC nylon (that is, the addition amount of long-chain active agent is 10% of the total mass of caprolactam).

[0036] Experimental Example 1 The MC nylon containing the long-chain active agent of Examples 1 to 8 and Comparative Example 1 was respectively tested for elongation at break according to standard GB / T 1040.2-2022 "Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics", and the results are shown in Table 1 below.

[0037] Table 1 Performance test results

[0038] Compared with Comparative Example 1, the elongation at break of the nylon material prepared by using the long-chain activator of Examples 1 to 8 is higher, indicating that the use of isocyanate with a functionality greater than 2 as the raw material of the long-chain activator and the compounding of polymethylene polyphenyl polyisocyanate and triphenylmethane triisocyanate improves the toughness of MC nylon.

[0039] Experimental Example 2 The friction coefficient of MC nylon containing the long-chain activator of Examples 8 to 11 was tested according to GB / T 3960-2016 "Test Methods for Sliding Friction and Wear of Plastics". The results are shown in Table 2 below.

[0040] Table 2 Performance test results

[0041] Compared with Example 8 and Example 11, the elongation at break of the nylon material prepared by using the long-chain activator of Examples 9-10 is higher, indicating that the wear resistance of MC nylon is improved by adding the raw material as the long-chain activator.

[0042] Experimental Example 3 According to the preparation method of the application example, the hardness, mechanical properties and crystallinity of MC nylon containing different addition amounts (0%~25%) of the long-chain active agent (prepared in Example 3) were tested respectively. The mechanical properties were tested in accordance with GB / T 1040.2-2022 "Determination of Tensile Properties of Plastics Part 2: Test Conditions for Molded and Extruded Plastics". The crystallinity was tested by differential scanning calorimetry (DSC method) by the Joint State Key Laboratory of Chemical Engineering (Zhejiang University). The results are shown in Table 3 below.

[0043] Table 3 Performance test results

[0044] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A long-chain activator for preparing toughened block MC nylon, characterized in that: The method comprises the following raw materials in parts by weight: 15-25 parts of caprolactam, 50-60 parts of polytetramethylene glycol, and 18-24 parts of isocyanate; The functionality of the isocyanate is >2.

2. The long-chain activator for preparing toughened block MC nylon according to claim 1, characterized in that: The isocyanate includes polymethylene polyphenyl polyisocyanate and / or triphenylmethane triisocyanate.

3. The long-chain activator for preparing toughened block MC nylon according to claim 1, characterized in that: The molecular weight of the polytetrahydrofuran ether glycol is 2000-3000.

4. The long-chain activator for preparing toughened block MC nylon according to claim 2, characterized in that: When the isocyanate is polymethylene polyphenyl polyisocyanate and triphenylmethane triisocyanate, the mass ratio of the polymethylene polyphenyl polyisocyanate to the triphenylmethane triisocyanate is 1:9 to 9:

1.

5. The long-chain activator for preparing toughened block MC nylon according to claim 4, characterized in that: The mass ratio of the polymethylene polyphenyl polyisocyanate to the triphenylmethane triisocyanate is 3:2-4:

1.

6. The long-chain activator for preparing toughened block MC nylon according to claim 1, characterized in that: The invention also comprises the following raw materials in parts by weight: 4 to 6 parts of boron nitride nanosheet composite material.

7. The long-chain activator for preparing toughened block MC nylon according to claim 6, characterized in that: The preparation method of the boron nitride nanosheet composite material comprises the following steps: mixing epoxysuccinic acid and a solvent, adding boron nitride nanosheets, and drying to obtain the boron nitride nanosheet composite material; The mass ratio of the epoxysuccinic acid, the solvent and the boron nitride nanosheets is 1-3:50:20; The boron nitride nanosheet has a sheet diameter of 1-3 μm and a thickness of less than 100 nm.

8. The method for preparing a long-chain activator for preparing toughened block MC nylon according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, reacting the caprolactam and isocyanate to obtain polylactam; S2. Mixing the polylactam and the remaining raw materials of the long-chain surfactant to obtain the long-chain surfactant.

9. The method for preparing a long-chain activator for preparing toughened block MC nylon according to claim 8, characterized in that: The reaction temperature is 160-175°C and the reaction time is 10-15 minutes; The mixing temperature is 115-125° C. and the mixing time is 8-9 hours.

10. Use of a long-chain activator for preparing toughened block MC nylon according to any one of claims 1 to 7 or a long-chain activator prepared by the preparation method according to any one of claims 8 to 9 in toughening MC nylon.

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