Toughened block MC nylon material taking long-chain active agent as cocatalyst

Abstract

The invention relates to the technical field of high polymer materials, and provides a toughened block MC nylon material taking a long-chain active agent as a cocatalyst, the toughened block MC nylon material comprises the following raw materials by weight: 100 parts of caprolactam, 5-10 parts of inorganic whisker, 6-12 parts of isocyanate, 6-12 parts of aromatic amine, 0.1-0.4 part of a basic catalyst, and 0-30 parts of a cocatalyst. According to the technical scheme, the problem of poor toughness of the MC nylon material in the related technology is solved, the long-chain active agent is adopted as the cocatalyst, the obtained MC nylon material is higher in toughness, meanwhile, the problem that the MC nylon product cracks in the production, processing, transportation, installation and use processes is solved, and the MC nylon material has good toughness. Especially, the effect on MC nylon products with the single piece being 500 kg or above and MC nylon products compounded with steel cores is particularly obvious.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and specifically, to a toughened block MC nylon material using a long-chain surfactant as a co-catalyst. Background Art

[0002] MC nylon, that is, monomer casting nylon, has been widely used in many fields such as machinery manufacturing, automotive industry, and chemical industry due to its high strength, self-lubrication and other characteristics. However, the molecular chain of MC nylon is mainly composed of methylene chain segments connected by amide bonds. Although the amide bonds provide certain polarity and intermolecular forces, the flexibility of the methylene chain segments is relatively limited. This molecular structure makes it insufficient for the molecular chains of MC nylon to stretch and rearrange when subjected to external force impact, and it is difficult to effectively absorb and disperse energy, resulting in poor toughness. At the same time, MC nylon usually has a high degree of crystallinity. Although the high degree of crystallinity gives MC nylon good dimensional stability, it reduces the mobility of the molecular chains. In the crystalline region, the molecular chains are arranged tightly and regularly, hindering the relative sliding of the molecular chains under the action of external force, making the material prone to brittle fracture under impact load and reducing the toughness. Therefore, it is necessary to obtain a high-toughness MC nylon material. Summary of the Invention

[0003] The present invention provides a toughened block MC nylon material using a long-chain surfactant as a co-catalyst, which solves the problem of poor toughness of MC nylon materials in the related art.

[0004] The technical solution of the present invention is as follows: The present invention provides a toughened block MC nylon material using a long-chain surfactant as a co-catalyst, which comprises the following raw materials in parts by weight: 100 parts of caprolactam, 5 - 10 parts of inorganic whiskers, 6 - 12 parts of isocyanate, 6 - 12 parts of aromatic amine, 0.1 - 0.4 parts of basic catalyst, and 0 - 30 parts of co-catalyst.

[0005] As a further technical solution, the inorganic whiskers include one or two of potassium titanate whiskers and silicon carbide whiskers.

[0006] In the present invention, the inorganic whiskers have an extremely high aspect ratio, and this unique structure endows the inorganic whiskers with special properties. When the inorganic whiskers are added to the MC nylon material, the inorganic whiskers are evenly dispersed in the MC nylon matrix like a strong "skeleton". When the material is subjected to external force, the whiskers can bear most of the load, effectively prevent the initiation and propagation of cracks, and maintain the integrity and stability of the structure. At the same time, during the friction process, the inorganic whiskers can form a lubricating protective film on the surface of the material, reduce the direct contact between the material and the friction pair, reduce the friction coefficient, and extend the service life of the MC nylon material.

[0007] As a further technical solution, the isocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate.

[0008] As a further technical solution, the aromatic amine includes one or more of dodecylaniline, hexadecylaniline and octadecylaniline.

[0009] As a further technical solution, when the aromatic amine is dodecylaniline and hexadecylaniline, the mass ratio of the dodecylaniline to the hexadecylaniline is 1:3 to 4.

[0010] In the present invention, the aromatic amine is compounded with dodecylaniline and hexadecylaniline. After reacting with the isocyanate, the surface of the inorganic whiskers is jointly modified, improving the wear resistance of the MC nylon material.

[0011] As a further technical solution, the basic catalyst includes one or more of sodium hydroxide, magnesium hydroxide, potassium hydroxide.

[0012] As a further technical solution, the cocatalyst includes a B long-chain surfactant; The B long-chain surfactant includes the following raw materials in parts by weight: 65 to 75 parts of polytetrahydrofuran ether glycol, 12 to 20 parts of caprolactam, and 10 to 15 parts of isocyanate.

[0013] In the present invention, the type of polytetrahydrofuran ether glycol can be PTMG 2000, PTMG 3000, etc.

[0014] As a further technical solution, the preparation method of the B long-chain surfactant includes the following steps: A1. React caprolactam and isocyanate in the raw materials of the B long-chain surfactant to obtain a reaction product; A2. Mix the reaction product and polytetrahydrofuran ether glycol to obtain the B long-chain surfactant.

[0015] In the present invention, the B long-chain surfactant is a multifunctional MC nylon modification aid. Its end group has an N-acylcaprolactam structure, which can not only act as a cocatalyst to initiate anionic polymerization of caprolactam, but also act as a toughening modifier for MC nylon to improve the toughness of the MC nylon material.

[0016] The present invention also provides a preparation method of the toughened block MC nylon material using the long-chain surfactant as a cocatalyst, including the following steps: 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 modified inorganic whiskers; S2. After mixing the modified inorganic whiskers and the remaining components of the toughened block MC nylon material, perform casting to obtain the MC nylon material.

[0017] As a further technical solution, in step S1, the temperature of the first mixing is 75 - 85°C, and the time is 3 - 5 h; the temperature of the second mixing is 85 - 95°C, and the time is 5 - 7 h; In step S2, the temperature of the mixing is 138 - 142°C, and the time is 10 - 15 min.

[0018] In the present invention, aromatic amine and isocyanate will react to modify the surface of the inorganic whiskers, improving the bonding force between the inorganic whiskers and the organic matrix, and effectively enhancing the toughness of the MC nylon material at the same time.

[0019] The working principle and beneficial effects of the present invention are as follows: In the present invention, components such as caprolactam, inorganic whiskers, isocyanate, and aromatic amine are used as raw materials for the MC nylon material. The introduction of inorganic whiskers, isocyanate, and aromatic amine improves the toughness of the MC nylon material. At the same time, it solves the problem of cracking of MC nylon products during production, processing, transportation, installation and use, especially for MC nylon products with a single piece weight of more than 500 kg and those compounded with steel cores, the effect is particularly obvious. Specific Embodiments

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments of the present invention fall within the scope of protection of the present invention.

[0021] In the following examples and comparative examples, the average diameter of potassium titanate whiskers is 0.5 μm, and the length is 10 μm; the average diameter of silicon carbide whiskers is 0.5 μm, and the length is 5 μm; the model of polytetrahydrofuran ether glycol is PTMG - 2000.

[0022] Example 1 The toughened block MC nylon material with a long - chain surfactant as a co - catalyst includes the following raw materials in parts by weight: 100 parts of caprolactam, 5 parts of potassium titanate whiskers, 5 parts of silicon carbide whiskers, 6 parts of toluene diisocyanate, 6 parts of hexadecyl aniline, and 0.1 part of sodium hydroxide; The preparation method of the toughened block MC nylon material with a long - chain surfactant as a co - catalyst includes the following steps: S1. According to the raw material formula of the toughened block MC nylon material: dissolve toluene diisocyanate in xylene, add potassium titanate whiskers and mix at 75 °C for 5 h, then add cetylaniline and mix at 85 °C for 7 h, filter, wash, and dry to obtain modified potassium titanate whiskers; the mass-volume ratio of toluene diisocyanate to xylene is 1 g:80 mL; S2. Mix the modified potassium titanate whiskers and the remaining components of the toughened block MC nylon material at 138 °C for 15 min, and then cast and mold to obtain the MC nylon material.

[0023] Example 2 The toughened block MC nylon material with a long-chain surfactant as a co-catalyst includes the following raw materials in parts by weight: 100 parts of caprolactam, 5 parts of silicon carbide whiskers, 12 parts of toluene diisocyanate, 12 parts of octadecylaniline, 0.4 part of potassium hydroxide, and 30 parts of B long-chain surfactant; The B long-chain surfactant includes the following raw materials in parts by weight: 75 parts of polytetrahydrofuran ether glycol, 20 parts of caprolactam, and 15 parts of toluene diisocyanate; The preparation method of the B long-chain surfactant includes the following steps: A1. Vacuum dehydrate caprolactam in the raw materials of the B long-chain surfactant at 140 °C for 10 min, then add toluene diisocyanate and react at 175 °C for 10 min to obtain a reaction product; A2. Mix the reaction product and polytetrahydrofuran ether glycol and react at 118 °C for 8 h to obtain the B long-chain surfactant; The preparation method of the toughened block MC nylon material with a long-chain surfactant as a co-catalyst includes the following steps: S1. According to the raw material formula of the toughened block MC nylon material: dissolve toluene diisocyanate in xylene, add silicon carbide whiskers and mix at 85 °C for 3 h, then add octadecylaniline and mix at 95 °C for 5 h, filter, wash, and dry to obtain modified silicon carbide whiskers; the mass-volume ratio of toluene diisocyanate to xylene is 1 g:80 mL; S2. Mix the modified silicon carbide whiskers and the remaining components of the toughened block MC nylon material at 142 °C for 10 min, and then cast and mold to obtain the MC nylon material.

[0024] Example 3 The toughened block MC nylon material with a long-chain surfactant as a co-catalyst includes the following raw materials in parts by weight: 100 parts of caprolactam, 6 parts of silicon carbide whiskers, 10 parts of toluene diisocyanate, 11 parts of cetylaniline, 0.2 part of sodium hydroxide, and 15 parts of B long-chain surfactant; The B long-chain surfactant includes the following raw materials in parts by weight: 70 parts of polytetrahydrofuran ether glycol, 16 parts of caprolactam, and 12 parts of toluene diisocyanate; Preparation method of B long-chain active agent, comprising the following steps: A1. After vacuum dehydrating caprolactam in the raw materials of the B long-chain active agent at 140 °C for 10 min, adding toluene diisocyanate and reacting at 160 °C for 15 min to obtain a reactant; A2. Mixing the reactant and polytetrahydrofuran ether glycol and reacting at 115 °C for 8.5 h to obtain the B long-chain active agent; Preparation method of toughened block MC nylon material using a long-chain active agent as a co-catalyst, comprising the following steps: S1. According to the raw material formula of the toughened block MC nylon material: dissolving toluene diisocyanate in xylene, adding silicon carbide whiskers and mixing at 80 °C for 4 h, then adding cetylaniline and mixing at 80 °C for 6 h, filtering, washing, and drying to obtain modified silicon carbide whiskers; the mass-volume ratio of toluene diisocyanate to xylene is 1 g:80 mL; S2. Mixing the modified silicon carbide whiskers and the remaining components of the toughened block MC nylon material at 140 °C for 12 min, and casting to obtain the MC nylon material.

[0025] Example 4 The difference between this example and Example 3 is only that cetylaniline is replaced by dodecylaniline.

[0026] Example 5 The difference between this example and Example 3 is only that one-fourth of the mass of cetylaniline is replaced by an equal amount of octadecylaniline.

[0027] Example 6 The difference between this example and Example 3 is only that one-fourth of the mass of cetylaniline is replaced by an equal amount of dodecylaniline.

[0028] Example 7 The difference between this example and Example 3 is only that one-fifth of the mass of cetylaniline is replaced by an equal amount of dodecylaniline.

[0029] Comparative Example 1 Toughened block MC nylon material using a long-chain active agent as a co-catalyst, comprising the following raw materials in parts by weight: 100 parts of caprolactam, 6 parts of silicon carbide whiskers, 0.2 part of sodium hydroxide, and 15 parts of B long-chain active agent; The B long-chain active agent comprises the following raw materials in parts by weight: 70 parts of polytetrahydrofuran ether glycol, 16 parts of caprolactam, and 12 parts of toluene diisocyanate; Preparation method of B long-chain active agent, comprising the following steps: A1. After vacuum dehydrating caprolactam in the raw materials of the B long-chain active agent at 140 °C for 10 min, toluene diisocyanate was added and reacted at 160 °C for 15 min to obtain a reaction product. A2. The reaction product and polytetrahydrofuran ether diol were mixed and reacted at 115 °C for 8.5 h to obtain the B long-chain active agent. A preparation method of a toughened block MC nylon material using a long-chain active agent as a co-catalyst, comprising the following steps: The silicon carbide whiskers and the remaining components of the toughened block MC nylon material were mixed at 140 °C for 12 min and then cast and molded to obtain the MC nylon material.

[0030] Comparative Example 2 The difference between this comparative example and Example 3 is only that hexadecylaniline is replaced by hexadecylamine.

[0031] Experimental Example 1 The elongation at break of the MC nylon materials prepared in Examples 1 to 3 and Comparative Example 1 was tested according to GB / T 1040.2-2022 "Plastics - Determination of tensile properties - Part 2: Test conditions for moulding and extrusion plastics", and the results are shown in Table 1 below.

[0032] Table 1 Test results of elongation at break

[0033] Compared with Comparative Example 1, the elongation at break of the MC nylon materials prepared in Examples 1 to 3 was higher, reaching more than 270%, indicating that after treating the inorganic whiskers with isocyanate and aromatic amine, the toughness of the MC nylon material was improved.

[0034] Experimental Example 2 Relying on the State Key Laboratory of Chemical Engineering Joint (Zhejiang University), the crystallinity of the MC nylon material prepared in Example 3 was tested by differential scanning calorimetry (DSC method). At the same time, according to the formula and preparation method of Example 3, only the addition amount of the B long-chain active agent (calculated as the mass percentage of the B long-chain active agent in caprolactam) was changed, and the influence of different addition amounts of the B long-chain active agent on the crystallinity of MC nylon was tested. The results are shown in Table 2 below.

[0035] Table 2 Test results of crystallinity

[0036] As can be seen from Table 2, adding the B long-chain active agent to the MC nylon material can reduce the crystallinity of the MC nylon material, making the MC nylon material have excellent toughness.

[0037] Experimental Example 3 The friction coefficient of the MC nylon materials prepared in Examples 3-7 and Comparative Example 2 was tested in accordance with GB / T 3960-2016 "Plastics - Methods of test for friction and wear under sliding conditions", and the results are shown in Table 3 below.

[0038] Table 3 Abrasion resistance test results

[0039] Compared with Comparative Example 2 and Examples 3-5, the MC nylon materials prepared in Examples 6-7 have a lower friction coefficient, indicating that when dodecylaniline and hexadecylaniline are used together as raw materials to modify inorganic whiskers, the abrasion resistance of the prepared MC nylon materials is more excellent.

[0040] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A toughened block MC nylon material using a long-chain activator as a co-catalyst, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of caprolactam, 5-10 parts of inorganic whiskers, 6-12 parts of isocyanate, 6-12 parts of aromatic amine, 0.1-0.4 parts of alkaline catalyst and 0-30 parts of co-catalyst.

2. The toughened block MC nylon material with a long-chain activator as a co-catalyst according to claim 1, characterized in that: The inorganic whiskers include one or both of potassium titanate whiskers and silicon carbide whiskers.

3. The toughened block MC nylon material with a long-chain activator as a co-catalyst according to claim 1, characterized in that: The isocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate.

4. The toughened block MC nylon material with a long-chain activator as a co-catalyst according to claim 1, characterized in that: The aromatic amine includes one or more of dodecylaniline, hexadecylaniline and octadecylaniline.

5. The toughened block MC nylon material with a long-chain activator as a co-catalyst according to claim 4, characterized in that: When the aromatic amines are dodecylaniline and hexadecylaniline, the mass ratio of the dodecylaniline to the hexadecylaniline is 1:3-4.

6. The toughened block MC nylon material with a long-chain activator as a co-catalyst according to claim 1, characterized in that: The alkaline catalyst includes one or more of sodium hydroxide, magnesium hydroxide and potassium hydroxide.

7. The toughened block MC nylon material with a long-chain activator as a co-catalyst according to claim 1, characterized in that: The co-catalyst includes a B long-chain activator; The B long-chain active agent comprises the following raw materials in parts by weight: 65-75 parts of polytetramethylene glycol, 12-20 parts of caprolactam, and 10-15 parts of isocyanate.

8. The toughened block MC nylon material with a long-chain activator as a co-catalyst according to claim 6, characterized in that: The preparation method of the B long-chain active agent comprises the following steps: A1, reacting the caprolactam and isocyanate in the raw materials of the B long-chain active agent to obtain a reactant; A2, the reactant and polytetrahydrofuran ether glycol are mixed to obtain B long-chain activator.

9. The method for preparing a toughened block MC nylon material using a long-chain activator as a co-catalyst according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, after dissolving the isocyanate, adding the inorganic whisker to carry out a first mixing, then adding the aromatic amine to carry out a second mixing, and drying to obtain a modified inorganic whisker; S2, mixing the modified inorganic whisker and the remaining components of the toughened block MC nylon material, and then casting to obtain the MC nylon material.

10. The method for preparing a toughened block MC nylon material using a long-chain activator as a co-catalyst according to claim 9, characterized in that: In step S1, the temperature of the first mixing is 75-85°C and the time is 3-5h; The second mixing temperature is 85-95°C and the time is 5-7h; In step S2, the mixing temperature is 138-142° C. and the mixing time is 10-15 min.

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