Modified nylon 66 material and preparation method thereof

Abstract

The invention discloses a modified nylon 66 material and a preparation method thereof, and belongs to the technical field of high polymer materials. The modified nylon 66 material is prepared from the following raw materials in parts by mass: 100 to 120 parts of modified nylon 66 resin, 20 to 30 parts of reinforced resin and 1 to 5 parts of antioxidant. The raw materials are mixed, fused and granulated to obtain the modified nylon 66 material. Wherein the modified nylon 66 resin contains an oxazolidinone ring and a silica group. According to the invention, an isocyanate compound and organosiloxane of epoxy groups are added in the polymerization stage of nylon 66 resin, and an oxazolidinone ring and a silica group are introduced while a polymerization reaction is accelerated, so that on one hand, the oxazolidinone ring and the silica group can be utilized to enhance the heat resistance and hydrolysis resistance of the material, and the nylon material is modified from a polymerization end; and on the other hand, the compatibility with reinforced resin can be improved, the effect of the reinforced material is fully exerted, and the mechanical property and hydrolysis resistance of the modified nylon material are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and specifically relates to a modified nylon 66 material and a preparation method thereof. Background Art

[0002] Nylon 66, also known as polyhexamethylene adipamide, is made by polycondensation of adipic acid and hexamethylenediamine and has a typical aliphatic polyamide structure. With excellent comprehensive properties such as shock resistance, heat resistance, wear resistance, and corrosion resistance, nylon 66 is widely used in the fields of civil yarn, industrial yarn, engineering plastics, etc., and has almost become a "synonym" for industrial yarn and engineering plastics.

[0003] However, polyamide nylon PA66 is hygroscopic. Since the main chain of its polymer material contains a large number of repeated amide groups, nylon is prone to hydrolysis with water or hydroxyl groups on organic matter in a high temperature and high humidity environment, which is commonly known as hydrolysis and alcoholysis reaction. Hydrolysis (alcoholysis reaction) is very harmful to nylon. The hydrolysis reaction will cut off the long carbon chain of nylon polymer, affecting the dimensional stability and electrical properties to a certain extent, especially the thickening of thin-walled parts, which will greatly reduce the mechanical strength of the plastic, reduce the service life of the material, and show yellowing and brittle fracture in the parts.

[0004] There are many modification technologies for PA66 hydrolysis resistance. The most commonly used method is to add glass fiber or other minerals to reduce the water absorption of nylon. However, fiber-added nylon is generally only used for modified and reinforced products, which has certain limitations. In the production and processing process, many product parts require nylon to be free of glass fiber, that is, fiber-free and filler-free nylon. Therefore, the modification methods described above are not suitable for this type of nylon products. Summary of the invention

[0005] The object of the present invention is to provide a modified nylon 66 material and a preparation method thereof, wherein the modified nylon 66 resin is polymerized without adding glass fiber, thereby enhancing the mechanical strength of the nylon 66 material and improving the hydrolysis resistance.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The present invention provides a modified nylon 66 material, which comprises the following raw materials in parts by mass:

[0008] 100-120 parts of modified nylon 66 resin, 20-30 parts of reinforcing resin, 1-5 parts of antioxidant;

[0009] The modified nylon 66 resin contains oxazolidinone ring and siloxy group.

[0010] Furthermore, the preparation steps of the modified nylon 66 resin are as follows:

[0011] Step 1, add adipic acid and hexamethylenediamine in a molar ratio of 1.05-1.1:1 into a flask, add into an ethanol solution and mix evenly, heat to 60-70°C to react for 12-24h, and after the reaction is completed, filter, wash with alcohol and dry to obtain nylon 66 salt;

[0012] Step 2: Prepare nylon 66 salt into a nylon 66 salt solution with a mass concentration of 50-60%, add it to a reaction kettle, add hexamethylenediamine according to 1-3% of the molar amount of hexamethylenediamine in step 1 into the reaction kettle, add isocyanate compound and epoxy-containing organosiloxane, evacuate and introduce nitrogen, heat to 200-250°C and react for 3-4h to obtain modified nylon resin.

[0013] Isocyanate compounds can not only act as activators for the polycondensation reaction of nylon 66 to accelerate the polymerization reaction, but also some isocyanate compounds can react with the epoxy groups in the epoxy-containing organosiloxane to generate compounds containing oxazolidinone rings, and the reaction formula is as follows:

[0014]

[0015] Compounds containing oxazolidinone rings have high heat resistance, and the oxazolidinone rings will preferentially react with moisture to generate volatile ketones or aldehydes, consuming moisture and preventing the amide groups in nylon 66 from reacting with water. At the same time, the introduction of long-chain siloxanes can improve the hydrophobicity of the material and reduce water absorption.

[0016] Furthermore, the isocyanate compound is one of p-phenylene isocyanate and diphenylmethane diisocyanate.

[0017] Furthermore, the epoxy-containing organosiloxane is one of γ-glycidyloxypropyltrimethoxysilane and 3-(2,3-epoxypropyloxy)propyltriethoxysilane.

[0018] Furthermore, the molar ratio of the isocyanate compound to the epoxy-containing organosiloxane is 2.3-3.0:1.

[0019] Furthermore, the mass of the epoxy-containing organosiloxane is 7-11% of the mass of the nylon 66 salt solution.

[0020] Furthermore, the reinforcing resin is one of polyphenylene sulfide resin and epoxy resin.

[0021] The compatibility of modified nylon 66 resin with polyphenylene sulfide resin or epoxy resin is improved due to the presence of siloxane. Polyphenylene sulfide resin has the characteristics of high mechanical strength, high temperature resistance, chemical resistance, flame retardancy, good thermal stability and low water absorption, while epoxy resin has excellent chemical stability and low water absorption.

[0022] Furthermore, the antioxidant is at least one of a phosphite antioxidant and a hindered phenol antioxidant.

[0023] The present invention also provides a method for preparing the modified nylon 66 material as described above, comprising the following steps:

[0024] The raw materials are weighed, dried and dehydrated, mixed, and put into a screw extruder, heated, melted, extruded and granulated to obtain a modified nylon 66 material.

[0025] Furthermore, the heating and melting temperature is 250-280°C.

[0026] Beneficial effects of the present invention:

[0027] The modified nylon 66 resin of the present invention contains oxazolidinone rings and siloxy groups. On the one hand, the oxazolidinone rings and siloxy groups can be used to enhance the heat resistance and hydrolysis resistance of the material, modify the nylon material from the polymerization end, and avoid using glass fiber as filler. On the other hand, the compatibility with the reinforced resin can be improved, the role of the reinforced material can be fully exerted, and the mechanical properties and hydrolysis resistance of the modified nylon material can be improved. DETAILED DESCRIPTION

[0028] 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.

[0029] Example 1

[0030] Preparation of modified 66 resin:

[0031] Step 1: Add adipic acid and hexamethylenediamine into a flask at a molar ratio of 1.05:1, add into an ethanol solution and mix evenly, heat to 60°C and react for 24 hours, and after the reaction is completed, filter, wash with alcohol and dry to obtain nylon 66 salt;

[0032] Step 2: prepare nylon 66 salt into a nylon 66 salt solution with a mass concentration of 60%, add it to a reactor, add hexamethylenediamine according to 1% of the molar amount of hexamethylenediamine in step 1 into the reactor, add p-phenylene isocyanate and γ-glycidyloxypropyltrimethoxysilane, the mass of γ-glycidyloxypropyltrimethoxysilane is 7% of the mass of the nylon 66 salt solution, the molar ratio of p-phenylene isocyanate to γ-glycidyloxypropyltrimethoxysilane is 2.3:1, evacuate and introduce nitrogen, heat to 230°C for reaction for 3 hours, and obtain a modified nylon resin.

[0033] Preparation of modified nylon 66 material:

[0034] The raw materials include, by mass, 120 parts of the modified nylon 66 resin prepared in this embodiment, 20 parts of polyphenylene sulfide resin, 3010 Antioxidant 1 part.

[0035] The raw materials were weighed and dried at 90° C. for 3 h, mixed and put into a screw extruder, heated and melted, extruded and granulated, and the heating and melting temperature was set at 280° C. to obtain a modified nylon 66 material.

[0036] Example 2

[0037] The difference from Example 1 is that the molar ratio of p-phenylene isocyanate and γ-glycidyloxypropyltrimethoxysilane in the preparation of modified 66 resin is adjusted to 2.6:1, and the modified nylon 66 resin prepared in this example is used to prepare the modified nylon 66 material, and the other steps and conditions are the same as in Example 1.

[0038] Example 3

[0039] The difference from Example 1 is that the molar ratio of p-phenylene isocyanate and γ-glycidyloxypropyltrimethoxysilane in the preparation of modified 66 resin is adjusted to 3.0:1, and the modified nylon 66 resin prepared in this example is used to prepare the modified nylon 66 material, and the other steps and conditions are the same as in Example 1.

[0040] Example 4

[0041] The difference from Example 2 is that the mass of γ-glycidyloxypropyltrimethoxysilane is 10% of the mass of the nylon 66 saline solution, and the modified nylon 66 resin prepared in this example is used to prepare the modified nylon 66 material. The other steps and conditions are the same as in Example 2.

[0042] Example 5

[0043] The difference from Example 2 is that the mass of γ-glycidyloxypropyltrimethoxysilane is 11% of the mass of the nylon 66 salt solution, and the modified nylon 66 resin prepared in this example is used to prepare the modified nylon 66 material. The other steps and conditions are the same as in Example 2.

[0044] Example 6

[0045] The difference from Example 4 is that the mass fractions of the raw materials for preparing the modified nylon 66 material are different, as follows:

[0046] 110 parts of modified nylon 66 resin prepared in Example 4, 25 parts of polyphenylene sulfide resin, 3010 antioxidant 3 parts.

[0047] Other conditions and steps are the same as in Example 4.

[0048] Example 7

[0049] The difference from Example 4 is that the mass fractions of the raw materials for preparing the modified nylon 66 material are different, as follows:

[0050] 100 parts of modified nylon 66 resin prepared in Example 4, 30 parts of epoxy resin, 3010 antioxidant 5 parts.

[0051] The heating and melting temperature was set to 250° C., and the other conditions and steps were the same as those in Example 4.

[0052] Comparative Example 1

[0053] Compared with Example 1, the difference of this comparative example is that commercially available nylon 66 resin is used to prepare the nylon material, and the specific steps are as follows:

[0054] The raw materials include: 120 parts of nylon 66 resin (Zytel 101L), 20 parts of polyphenylene sulfide resin, 3010 Antioxidant 1 part.

[0055] The raw materials were weighed and dried at 90° C. for 3 h, mixed and put into a screw extruder, heated and melted, extruded and granulated, and the heating and melting temperature was set to 280° C. to obtain nylon 66 material.

[0056] The nylon materials prepared in Examples 1 to 7 and Comparative Example 1 were subjected to performance tests by injection molding standard specimens according to ISO527-1 standard, and then immersed in water for 5000 hours before testing. The results are shown in Table 1:

[0057] Table 1

[0058]

[0059] As can be seen from Table 1, the molar ratio of isocyanate compound and siloxane is adjusted in Examples 1 to 3, wherein the hydrolysis resistance and mechanical properties of the material at the molar ratio of Example 2 are better than those of materials prepared at other molar ratios. Examples 4 and 5 increase the proportion of siloxane in the polymerization process on the basis of the molar ratio of Example 2, and increase the content of oxazolidinone ring and siloxy group in the modified nylon 66 resin compared with Example 2, thereby improving the hydrolysis resistance of the material. The reinforcing resins used to prepare the modified nylon materials in Examples 6 and 7 are different, but by controlling the proportions, the prepared modified nylon 66 material has excellent comprehensive performance. The modified nylon 66 material prepared in Example 1 has significantly better performance than the nylon 66 material of Comparative Example 1. The modified nylon 66 resin has better compatibility with the reinforcing resin while improving its own hydrolysis resistance and mechanical strength, and the prepared nylon 66 material has excellent performance.

[0060] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0061] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A modified nylon 66 material, characterized in that: The following raw materials are included by weight: 100-120 parts of modified nylon 66 resin, 20-30 parts of reinforcing resin, 1-5 parts of antioxidant; The modified nylon 66 resin contains oxazolidinone ring and siloxy group.

2. A modified nylon 66 material according to claim 1, characterized in that: The preparation steps of the modified nylon 66 resin are as follows: Step 1, add adipic acid and hexamethylenediamine into a flask at a molar ratio of 1.0-1.05:1, add into an ethanol solution and mix evenly, heat to 60-70°C to react for 12-24h, and after the reaction is completed, filter, wash with alcohol and dry to obtain nylon 66 salt; Step 2: Prepare nylon 66 salt into a nylon 66 salt solution with a mass concentration of 50-60%, add it to a reaction kettle, add hexamethylenediamine according to 1-3% of the molar amount of hexamethylenediamine in step 1 into the reaction kettle, add isocyanate compound and epoxy-containing organosiloxane, evacuate and introduce nitrogen, heat to 200-250°C and react for 3-4h to obtain modified nylon resin.

3. A modified nylon 66 material according to claim 2, characterized in that: The isocyanate compound is one of p-phenylene isocyanate and diphenylmethane diisocyanate.

4. A modified nylon 66 material according to claim 2, characterized in that: The epoxy-containing organosiloxane is one of γ-glycidyloxypropyltrimethoxysilane and 3-(2,3-epoxypropyloxy)propyltriethoxysilane.

5. The modified nylon 66 material according to claim 2, characterized in that: The molar ratio of the isocyanate compound to the epoxy-containing organosiloxane is 2.3-3.0:

1.

6. The modified nylon 66 material according to claim 2, characterized in that: The mass of the epoxy-containing organosiloxane is 7-11% of the mass of the nylon 66 salt solution.

7. The modified nylon 66 material according to claim 1, characterized in that: The reinforcing resin is one of polyphenylene sulfide resin and epoxy resin.

8. The modified nylon 66 material according to claim 1, characterized in that: The antioxidant is at least one of a phosphite antioxidant and a hindered phenol antioxidant.

9. A method for preparing the modified nylon 66 material according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw materials are weighed, dried and dehydrated, mixed, and put into a screw extruder, heated, melted, extruded and granulated to obtain a modified nylon 66 material.

10. The method for preparing a modified nylon 66 material according to claim 9, characterized in that: The heating and melting temperature is 200-280°C.

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