A toughened block MC nylon material using long-chain activators as co-catalysts

Abstract

This invention relates to the field of polymer materials technology, and proposes a toughened block MC nylon material using a long-chain activator as a co-catalyst, comprising the following raw materials in parts by weight: 100 parts caprolactam, 5-10 parts inorganic whiskers, 6-12 parts isocyanate, 6-12 parts aromatic amine, 0.1-0.4 parts alkaline catalyst, and 0-30 parts co-catalyst. This technical solution solves the problem of poor toughness in related MC nylon materials. By using a long-chain activator as the co-catalyst, the resulting MC nylon material exhibits higher toughness. It also solves the problem of cracking in MC nylon products during production, processing, transportation, installation, and use, especially for MC nylon products weighing over 500 kg or those combined with a steel core.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a toughened block MC nylon material using a long-chain activator as a co-catalyst. Background Technology

[0002] MC nylon, or monomer-cast nylon, is widely used in machinery manufacturing, automotive industry, chemical industry, and many other fields due to its high strength and self-lubricating properties. However, the molecular chain of MC nylon is mainly composed of methylene segments linked by amide bonds. Although amide bonds provide a certain degree of polarity and intermolecular forces, the flexibility of the methylene segments is relatively limited. This molecular structure makes MC nylon less capable of stretching and rearranging its molecular chains when subjected to external impact, making it difficult to effectively absorb and disperse energy, resulting in poor toughness. At the same time, MC nylon typically has a high degree of crystallinity. While high crystallinity gives MC nylon good dimensional stability, it reduces the mobility of the molecular chains. In crystalline regions, the molecular chains are tightly and regularly arranged, hindering relative sliding of the molecular chains under external forces. This makes the material prone to brittle fracture under impact loads, reducing toughness. Therefore, there is a need to obtain a high-toughness MC nylon material. Summary of the Invention

[0003] This invention proposes a toughened block MC nylon material using a long-chain activator as a co-catalyst, which solves the problem of poor toughness of MC nylon materials in related technologies.

[0004] The technical solution of the present invention is as follows:

[0005] This invention proposes a toughened block MC nylon material using a long-chain activator as a co-catalyst, comprising the following raw materials in parts by weight: 100 parts caprolactam, 5-10 parts inorganic whiskers, 6-12 parts isocyanate, 6-12 parts aromatic amine, 0.1-0.4 parts alkaline catalyst, and 0-30 parts co-catalyst.

[0006] As a further technical solution, the inorganic whiskers include one or both of potassium titanate whiskers and silicon carbide whiskers.

[0007] In this invention, the inorganic whiskers possess an extremely high aspect ratio. This unique structure endows the inorganic whiskers with special properties. When added to MC nylon material, the inorganic whiskers act like a robust "skeleton," uniformly dispersed within the MC nylon matrix. When the material is subjected to external forces, the whiskers can bear most of the load, effectively preventing the initiation and propagation of cracks, maintaining the integrity and stability of the structure. Simultaneously, during friction, the inorganic whiskers can form a protective film with lubricating properties on the material surface, reducing direct contact between the material and the friction pair, lowering the coefficient of friction, and extending the service life of the MC nylon material.

[0008] As a further technical solution, the isocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate.

[0009] As a further technical solution, the aromatic amine includes one or more of dodecylaniline, hexadecylaniline, and octadecylaniline.

[0010] As a further technical solution, when the aromatic amine is dodecylaniline and hexadecylaniline, the mass ratio of dodecylaniline to hexadecylaniline is 1:3~4.

[0011] In this invention, the aromatic amines are compounded using dodecylaniline and hexadecylaniline, and after reacting with isocyanate, they jointly modify the surface of inorganic whiskers, thereby improving the wear resistance of MC nylon materials.

[0012] As a further technical solution, the alkaline catalyst includes one or more of sodium hydroxide, magnesium hydroxide, and potassium hydroxide.

[0013] As a further technical solution, the co-catalyst includes a B-long-chain activator;

[0014] The B-chain activator comprises the following raw materials in parts by weight: 65-75 parts of polytetrahydrofuran ether diol, 12-20 parts of caprolactam, and 10-15 parts of isocyanate.

[0015] In this invention, the polytetrahydrofuran ether diol can be of the type PTMG 2000, PTMG 3000, etc.

[0016] As a further technical solution, the preparation method of the B-chain surfactant includes the following steps:

[0017] A1. The caprolactam and isocyanate in the raw materials of the B long-chain surfactant are reacted to obtain the reactants;

[0018] A2. The reactants and polytetrahydrofuran ether diol are mixed to obtain long-chain activator B.

[0019] In this invention, the B long-chain activator is a multifunctional MC nylon modifier. Its end group has an N-acylcaprolactam structure, which can act as a co-catalyst to initiate the anionic polymerization of caprolactam, and also as a toughening modifier for MC nylon to improve the toughness of MC nylon materials.

[0020] This invention also proposes a method for preparing a toughened block MC nylon material using a long-chain activator as a co-catalyst, comprising the following steps:

[0021] S1. After dissolving the isocyanate, add the inorganic whiskers for the first mixing, then add the aromatic amine for the second mixing, and dry to obtain the modified inorganic whiskers.

[0022] S2. The modified inorganic whiskers and the remaining components of the toughened block MC nylon material are mixed and then cast to obtain the MC nylon material.

[0023] As a further technical solution, in step S1, the temperature of the first mixing is 75~85℃ and the time is 3~5h;

[0024] The second mixing is performed at a temperature of 85-95°C for 5-7 hours.

[0025] In step S2, the mixing temperature is 138~142℃ and the time is 10~15min.

[0026] In this invention, aromatic amines react with isocyanates to modify the surface of inorganic whiskers, thereby improving the bonding force between inorganic whiskers and the organic matrix, and effectively enhancing the toughness of MC nylon materials.

[0027] The working principle and beneficial effects of this invention are as follows:

[0028] In this invention, caprolactam, inorganic whiskers, isocyanate, and aromatic amines are used as raw materials for MC nylon materials. The introduction of inorganic whiskers, isocyanate, and aromatic amines improves the toughness of MC nylon materials. At the same time, it solves the problem of cracking of MC nylon products during production, processing, transportation, installation, and use. The effect is particularly obvious for MC nylon products with a single piece weighing more than 500 kg and those combined with steel cores. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] In the following examples and comparative examples, the average diameter of the potassium titanate whiskers was 0.5 μm and the length was 10 μm; the average diameter of the silicon carbide whiskers was 0.5 μm and the length was 5 μm; and the polytetrahydrofuran ether diol was PTMG-2000.

[0031] Example 1

[0032] Toughened block MC nylon material with long-chain activators as co-catalysts includes the following raw materials in parts by weight: 100 parts caprolactam, 5 parts potassium titanate whiskers, 5 parts silicon carbide whiskers, 6 parts toluene diisocyanate, 6 parts hexadecylaniline, and 0.1 parts sodium hydroxide.

[0033] A method for preparing toughened block MC nylon materials using long-chain activators as co-catalysts includes the following steps:

[0034] S1. According to the raw material formula of toughened block MC nylon material: dissolve toluene diisocyanate in xylene, add potassium titanate whiskers and mix at 75°C for 5 hours, then add hexadecylaniline and mix at 85°C for 7 hours, filter, wash and dry to obtain modified potassium titanate whiskers; the mass-volume ratio of toluene diisocyanate to xylene is 1g:80mL.

[0035] S2. The modified potassium titanate whiskers and the remaining components of the toughened block MC nylon material are mixed at 138°C for 15 minutes and then cast to obtain the MC nylon material.

[0036] Example 2

[0037] Toughened block MC nylon material with long-chain activator as co-catalyst includes the following raw materials in parts by weight: 100 parts caprolactam, 5 parts silicon carbide whiskers, 12 parts toluene diisocyanate, 12 parts octadecylaniline, 0.4 parts potassium hydroxide, and 30 parts B long-chain activator.

[0038] B long-chain surfactant comprises the following raw materials in parts by weight: 75 parts polytetrahydrofuran ether diol, 20 parts caprolactam, and 15 parts toluene diisocyanate.

[0039] The preparation method of B long-chain surfactant includes the following steps:

[0040] A1. After dehydrating caprolactam in the raw material of long-chain surfactant B under vacuum at 140°C for 10 min, toluene diisocyanate is added and reacted at 175°C for 10 min to obtain the reactant.

[0041] A2. The reactants and polytetrahydrofuran ether diol were mixed and reacted at 118°C for 8 hours to obtain long-chain activator B.

[0042] A method for preparing toughened block MC nylon materials using long-chain activators as co-catalysts includes the following steps:

[0043] S1. According to the raw material formula of toughened block MC nylon material: dissolve toluene diisocyanate in xylene, add silicon carbide whiskers and mix at 85°C for 3 hours, then add octadecylaniline and mix at 95°C for 5 hours, filter, wash, and dry to obtain modified silicon carbide whiskers; the mass-volume ratio of toluene diisocyanate to xylene is 1g:80mL.

[0044] S2. The modified silicon carbide whiskers and the remaining components of the toughened block MC nylon material are mixed at 142°C for 10 minutes and then cast to obtain the MC nylon material.

[0045] Example 3

[0046] Toughened block MC nylon material with long-chain activator as co-catalyst includes the following raw materials in parts by weight: 100 parts caprolactam, 6 parts silicon carbide whiskers, 10 parts toluene diisocyanate, 11 parts hexadecylaniline, 0.2 parts sodium hydroxide, and 15 parts B long-chain activator.

[0047] B long-chain surfactant comprises the following raw materials in parts by weight: 70 parts polytetrahydrofuran ether diol, 16 parts caprolactam, and 12 parts toluene diisocyanate;

[0048] The preparation method of B long-chain surfactant includes the following steps:

[0049] A1. After dehydrating caprolactam in the raw material of long-chain surfactant B under vacuum at 140°C for 10 min, toluene diisocyanate is added and reacted at 160°C for 15 min to obtain the reactant.

[0050] A2. The reactants and polytetrahydrofuran ether diol were mixed and reacted at 115°C for 8.5 h to obtain long-chain activator B.

[0051] A method for preparing toughened block MC nylon materials using long-chain activators as co-catalysts includes the following steps:

[0052] S1. According to the raw material formula of toughened block MC nylon material: dissolve toluene diisocyanate in xylene, add silicon carbide whiskers and mix at 80°C for 4 hours, then add hexadecylaniline and mix at 80°C for 6 hours, filter, wash, and dry to obtain modified silicon carbide whiskers; the mass-volume ratio of toluene diisocyanate to xylene is 1g:80mL.

[0053] S2. The modified silicon carbide whiskers and the remaining components of the toughened block MC nylon material are mixed at 140°C for 12 minutes and then cast to obtain the MC nylon material.

[0054] Example 4

[0055] The only difference between this embodiment and Embodiment 3 is that hexadecylaniline is replaced with dodecylaniline.

[0056] Example 5

[0057] The only difference between this embodiment and Embodiment 3 is that one-quarter of the mass of hexadecylaniline is replaced with an equal amount of octadecylaniline.

[0058] Example 6

[0059] The only difference between this embodiment and Embodiment 3 is that one-quarter of the mass of hexadecylaniline is replaced with an equal amount of dodecylaniline.

[0060] Example 7

[0061] The only difference between this embodiment and Embodiment 3 is that one-fifth of the mass of hexadecylaniline is replaced with an equal amount of dodecylaniline.

[0062] Comparative Example 1

[0063] Toughened block MC nylon material with long-chain activator as co-catalyst includes the following raw materials in parts by weight: 100 parts caprolactam, 6 parts silicon carbide whiskers, 0.2 parts sodium hydroxide, and 15 parts B long-chain activator.

[0064] B long-chain surfactant comprises the following raw materials in parts by weight: 70 parts polytetrahydrofuran ether diol, 16 parts caprolactam, and 12 parts toluene diisocyanate;

[0065] The preparation method of B long-chain surfactant includes the following steps:

[0066] A1. After dehydrating caprolactam in the raw material of long-chain surfactant B under vacuum at 140°C for 10 min, toluene diisocyanate is added and reacted at 160°C for 15 min to obtain the reactant.

[0067] A2. The reactants and polytetrahydrofuran ether diol were mixed and reacted at 115°C for 8.5 h to obtain long-chain activator B.

[0068] A method for preparing toughened block MC nylon materials using long-chain activators as co-catalysts includes the following steps:

[0069] The silicon carbide whiskers and the remaining components of the toughened block MC nylon material were mixed at 140°C for 12 minutes and then cast to obtain the MC nylon material.

[0070] Comparative Example 2

[0071] The only difference between this comparative example and Example 3 is that hexadecylaniline is replaced with hexadecylamine.

[0072] Experimental Example 1

[0073] The MC nylon materials prepared in Examples 1-3 and Comparative Example 1 were tested for elongation at break according to GB / T 1040.2-2022 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics". The results are shown in Table 1 below.

[0074] Table 1 Results of Elongation at Break Test

[0075]

[0076] Compared with Comparative Example 1, the MC nylon materials prepared in Examples 1-3 had a higher elongation at break, reaching over 270%, indicating that the treatment of inorganic whiskers with isocyanate and aromatic amine improved the toughness of the MC nylon materials.

[0077] Experimental Example 2

[0078] The crystallinity of the MC nylon material prepared in Example 3 was tested by differential scanning calorimetry (DSC) using the State Key Laboratory of Chemical Engineering (Zhejiang University). At the same time, following the formulation and preparation method of Example 3, only the amount of B long-chain surfactant added was changed (based on the mass percentage of B long-chain surfactant to caprolactam). The effect of different amounts of B long-chain surfactant added on the crystallinity of MC nylon was tested. The results are shown in Table 2 below.

[0079] Table 2 Crystallinity Test Results

[0080]

[0081] As shown in Table 2, adding long-chain B activators to MC nylon materials can reduce the crystallinity of MC nylon materials, thus giving MC nylon materials excellent toughness.

[0082] Experimental Example 3

[0083] The friction coefficients of the MC nylon materials prepared in Examples 3-7 and Comparative Example 2 were tested according to GB / T 3960-2016 "Plastics Sliding Friction and Wear Test Method". The results are shown in Table 3 below.

[0084] Table 3 Abrasion resistance test results

[0085]

[0086] Compared with Comparative Example 2 and Examples 3-5, the MC nylon materials prepared in Examples 6-7 have a lower coefficient of friction, indicating that when dodecylaniline and hexadecylaniline are used together as raw materials to modify inorganic whiskers, the MC nylon materials prepared have better wear resistance.

[0087] The above are merely 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 within the protection scope of the present invention.

Claims

1. A toughened block MC nylon material with long chain active agent as a co-catalyst, characterized in that, The raw materials include the following weight parts: caprolactam 100 parts, inorganic whisker 5-10 parts, isocyanate 6-12 parts, aromatic amine 6-12 parts, basic catalyst 0.1-0.4 parts, and co-catalyst 0-30 parts; The co-catalyst includes B long-chain active agent; The B long-chain active agent includes the following weight parts of raw materials: polytetrahydrofuran ether glycol 65-75 parts, caprolactam 12-20 parts, and isocyanate 10-15 parts; The preparation method of the B long-chain active agent includes the following steps: A1, reacting caprolactam and isocyanate in the raw materials of the B long-chain active agent to obtain a reaction product; A2, mixing the reaction product and polytetrahydrofuran ether glycol to obtain the B long-chain active agent.

2. A toughened block MC nylon material with long chain active agent as co-catalyst according to claim 1, characterized in that, The inorganic whisker includes one or both of potassium titanate whisker and silicon carbide whisker.

3. The toughened block MC nylon material with long chain active agent as cocatalyst according to claim 1, characterized in that, The isocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, and diphenyl methane diisocyanate.

4. The toughened block MC nylon material with long chain active agent as cocatalyst according to claim 1, characterized in that, The aromatic amine includes one or more of dodecyl aniline, hexadecyl aniline, and octadecyl aniline.

5. A toughened block MC nylon material with long chain active agent as co-catalyst according to claim 4, characterized in that, When the aromatic amine is dodecyl aniline and hexadecyl aniline, the mass ratio of the dodecyl aniline to the hexadecyl aniline is 1:3-4.

6. The toughened block MC nylon material with long chain active agent as cocatalyst according to claim 1, characterized in that, The basic catalyst includes one or more of sodium hydroxide, magnesium hydroxide, and potassium hydroxide.

7. A process for the preparation of a toughened block MC nylon material with long chain activator as co-catalyst according to any one of claims 1 to 6, characterized in that, The method includes the following steps: S1, dissolving the isocyanate, then adding the inorganic whisker for first mixing, adding the aromatic amine for second mixing, and drying to obtain modified inorganic whisker; S2, mixing the modified inorganic whisker and the remaining components of the toughening block MC nylon material, and then casting to obtain the MC nylon material.

8. A process for the preparation of a toughened block MC nylon material with long chain activator as co-catalyst according to claim 7, characterized in that, In step S1, the temperature of the first mixing is 75-85°C, and the time is 3-5h; The temperature of the second mixing is 85-95°C, and the time is 5-7h; In step S2, the temperature of the mixing is 138-142°C, and the time is 10-15min.

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