Light aging resistant polyamide material
By using the light stabilizer generated by the reaction of melamine and vanillin in the polyamide material, combined with the synergistic effect of epoxy-modified nano zinc oxide, the problem of the polyamide material being prone to yellowing is solved, and the low yellowing and high mechanical properties of the material are achieved.
Patent Information
- Application Number
- CN202411906622.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-05-13
AI Technical Summary
Polyamide materials are easily oxidized and turned yellow during drying, injection molding and outdoor use, which limits their application in light-colored products.
The intermediate was formed by the Schiff base reaction using melamine and vanillin, and reacted with epoxy modified nano zinc oxide under the action of a phase transfer catalyst to prepare a photo stabilizer for polyamide. This light stabilizer improves the light stability of polyamide materials through the synergistic effect of the vanillin structure and the triazine ring and the zinc oxide structure.
The degree of yellowing of the polyamide material is significantly reduced while maintaining its high mechanical properties, including tensile strength, bending strength and impact strength.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to a light aging resistant polyamide material, belonging to the technical field of polymer materials. Background Art
[0002] Polyamide generally refers to nylon, which is a general term for thermoplastic resins containing repeated amide groups -[NHCO]- on the main chain of the molecule. Nylon is a tough, angular, translucent or milky white crystalline resin. As an engineering plastic, the molecular weight of nylon is generally 15,000 to 30,000. Nylon has high mechanical strength, high softening point, heat resistance, low friction coefficient, and good electrical insulation. However, the amide bond in its molecular structure has strong reducing properties, and it is very easy to be oxidized and yellowed during the drying process, injection molding process, and outdoor use, which limits its application in light-colored products.
[0003] There are two main methods to improve nylon yellowing. One method is to directly add antioxidants to alleviate the yellowing process; the other method is to prepare an alloy by adding some similar materials with low discoloration. However, both methods have disadvantages. In the first method, the antioxidant has a small molecular weight and is difficult to disperse evenly in polyamide, so the improvement effect is limited; in the second method, directly adding low discoloration materials to prepare alloys will damage the strength and other properties of polyamide.
[0004] Therefore, there is an urgent need to develop a polyamide material with low yellowing and high mechanical properties. Summary of the invention
[0005] The purpose of the present invention is to provide a light aging resistant polyamide material, so as to provide a polyamide material with low yellowing and high mechanical properties.
[0006] The invention provides a light aging resistant polyamide material, comprising the following components in parts by weight: 30-45 parts of polyamide, 2-5 parts of a toughening agent, 3-5 parts of glass fibers and 1-1.5 parts of a light stabilizer. The preparation method of the light stabilizer comprises the following steps: firstly subjecting melamine and excess 3-methoxy-4-hydroxybenzaldehyde to a Schiff base reaction to obtain an intermediate; and then subjecting the intermediate and epoxy-modified nano zinc oxide to a mixed reaction at 85-95 DEG C under the action of a phase transfer catalyst to obtain the light stabilizer.
[0007] Preferably, the molar ratio of melamine to 3-methoxy-4-hydroxybenzaldehyde is 50:(300-400).
[0008] Preferably, the temperature of the Schiff base reaction is 70-80° C. and the time is 6-10 hours.
[0009] Preferably, the preparation method of the epoxy-modified nano zinc oxide is as follows: nano zinc oxide and epoxy silane coupling agent in a mass ratio of (7-10): (5-6) are mixed and reacted in a solvent at a temperature of 85-95° C. for 8-12 hours; the solvent is mainly composed of ethanol and water in a mass ratio of 60: (20-30), and the pH of the solvent is 3.5-4.5.
[0010] Preferably, the epoxy silane coupling agent is γ-glycidyloxypropyltrimethoxysilane.
[0011] Preferably, the mass ratio of the intermediate to the epoxy-modified nano zinc oxide is 5:(25-30).
[0012] Preferably, the mass ratio of the intermediate, epoxy-modified nano zinc oxide and phase transfer catalyst is 5:(25-30):(2-3).
[0013] Preferably, the phase transfer catalyst is tetrabutylammonium bromide.
[0014] Preferably, the mixing reaction time of the intermediate and epoxy-modified nano zinc oxide is 10 to 12 hours.
[0015] Preferably, the polyamide is nylon 66, and the toughening agent is maleic anhydride grafted polyethylene.
[0016] The beneficial effects of the present invention are as follows:
[0017] (1) The present invention utilizes melamine and vanillin to react with a Schiff base, combines the vanillin structure and the triazine ring through a chemical bond, and then utilizes the phenolic hydroxyl group on the vanillin structure to react with the epoxy group on the epoxy-modified nano zinc oxide to prepare a light stabilizer for polyamide. The experimental results show that the zinc oxide structure in the light stabilizer can work synergistically with the vanillin structure and the triazine ring to improve the light stabilization effect and reduce the yellowing degree of the polyamide material.
[0018] (2) The present invention grafts the vanillin structure and the triazine ring onto the nano zinc oxide particles in the form of chemical bonds, thereby achieving pre-dispersion of the vanillin structure and the triazine ring on the surface of the nano zinc oxide particles, and improving the uniformity of the dispersion of the vanillin structure and the triazine ring on the surface of the nano zinc oxide particles; at the same time, nano zinc oxide is a solid particle, which is easier to be evenly dispersed in polyamide than small molecular organic matter, thereby improving the anti-yellowing performance of the material.
[0019] (3) The light aging resistant polyamide material of the present invention has good yellowing resistance and high tensile strength, bending strength and impact strength. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1The figure is a comparison result of the tensile strength of the light aging resistant polyamide materials before and after the aging experiment of each embodiment of the present invention and the comparative example;
[0021] Figure 2 The figure is a comparison result of the bending strength of the light aging resistant polyamide materials of each embodiment of the present invention and the comparative example before and after the aging experiment;
[0022] Figure 3 The figure is a comparison result of the impact strength of the light aging resistant polyamide materials of the embodiments of the present invention and the comparative examples before and after the aging experiment;
[0023] Figure 4 The figure is a comparison result of the yellowness index of the light aging resistant polyamide materials of the embodiments of the present invention and the comparative example before and after the aging experiment. DETAILED DESCRIPTION
[0024] The following examples are intended to further illustrate the present invention rather than to limit the scope of protection of the present invention.
[0025] Example 1
[0026] The light aging resistant polyamide material of this embodiment includes the following components in parts by weight: 30 parts of nylon 66, 2 parts of toughening agent, 3 parts of glass fiber, and 1 part of light stabilizer; wherein the toughening agent is maleic anhydride grafted polyethylene; the preparation method of the light stabilizer is as follows:
[0027] (1) adding 50 mmol of melamine to 350 mL of methanol and fully dissolving it to obtain a melamine solution; adding 300 mol of vanillin (3-methoxy-4-hydroxybenzaldehyde) to 450 mL of methanol and fully dissolving it to obtain a vanillin solution; then adding the melamine solution to a reactor equipped with a reflux condenser, and then dripping the vanillin solution into the melamine solution. After the dripping is completed, heating the materials in the reactor to 70° C., stirring and reacting for 10 hours, and after the reaction is completed, removing the methanol by rotary evaporation, and then washing the obtained solid with ethanol to remove the unreacted vanillin, thereby obtaining an intermediate;
[0028] (2) Add 60 g of ethanol and 20 g of water into the reactor, then add 5 g of γ-glycidyloxypropyltrimethoxysilane into the reactor, then add an appropriate amount of hydrochloric acid into the reactor, adjust the pH of the material in the reactor to 3.5, then add 10 g of nano zinc oxide into the reactor, stir evenly, then heat the material in the reactor to 95 ° C, react for 12 hours under stirring and reflux conditions, filter after the reaction, wash the filter cake with ethanol, and dry to obtain modified nano zinc oxide.
[0029] (3) 5 g of the intermediate, 30 g of modified nano zinc oxide, 3 g of tetrabutylammonium bromide and 1500 mL of dichloromethane were added to the reactor, and the materials in the reactor were heated to 50° C. and stirred for 12 h. After the reaction was completed, the mixture was filtered, and the filter cake was washed with ethanol and dried to obtain a light stabilizer.
[0030] Example 2
[0031] The light aging resistant polyamide material of this embodiment includes the following components in parts by weight: 45 parts of nylon 66, 5 parts of toughening agent, 5 parts of glass fiber, and 1.5 parts of light stabilizer; wherein the toughening agent is maleic anhydride grafted polyethylene; the preparation method of the light stabilizer is as follows:
[0032] (1) adding 50 mmol of melamine to 300 mL of methanol and fully dissolving it to obtain a melamine solution; adding 400 mol of vanillin (3-methoxy-4-hydroxybenzaldehyde) to 600 mL of methanol and fully dissolving it to obtain a vanillin solution; then adding the melamine solution to a reactor equipped with a reflux condenser, and then dropping the vanillin solution into the melamine solution. After the dropping is completed, heating the materials in the reactor to 80° C., stirring and reacting for 6 hours, and after the reaction is completed, removing methanol by rotary evaporation, and then washing the obtained solid with ethanol to remove unreacted vanillin, thereby obtaining an intermediate;
[0033] (2) Add 60 g of ethanol and 30 g of water into the reactor, then add 6 g of γ-glycidyloxypropyltrimethoxysilane into the reactor, then add an appropriate amount of hydrochloric acid into the reactor, adjust the pH of the material in the reactor to 4.5, then add 7 g of nano zinc oxide into the reactor, stir evenly, then heat the material in the reactor to 85 ° C, react for 8 hours under stirring and reflux conditions, filter after the reaction, wash the filter cake with ethanol, and dry to obtain modified nano zinc oxide.
[0034] (3) 5 g of the intermediate, 25 g of modified nano zinc oxide, 2 g of tetrabutylammonium bromide and 1500 mL of dichloromethane were added to the reactor, and the materials in the reactor were heated to 40° C. and stirred for 10 h. After the reaction was completed, the mixture was filtered, and the filter cake was washed with ethanol and dried to obtain a light stabilizer.
[0035] Example 3
[0036] The light aging resistant polyamide material of this embodiment includes the following components in parts by weight: 40 parts of nylon 66, 3 parts of toughening agent, 4 parts of glass fiber, and 1.2 parts of light stabilizer; wherein the toughening agent is maleic anhydride grafted polyethylene; the preparation method of the light stabilizer is as follows:
[0037] (1) adding 50 mmol of melamine to 320 mL of methanol and fully dissolving it to obtain a melamine solution; adding 350 mol of vanillin (3-methoxy-4-hydroxybenzaldehyde) to 500 mL of methanol and fully dissolving it to obtain a vanillin solution; then adding the melamine solution to a reactor equipped with a reflux condenser, and then dropping the vanillin solution into the melamine solution. After the dropping is completed, heating the materials in the reactor to 75° C., stirring and reacting for 8 hours, and after the reaction is completed, removing methanol by rotary evaporation, and then washing the obtained solid with ethanol to remove unreacted vanillin, thereby obtaining an intermediate;
[0038] (2) Add 60 g of ethanol and 25 g of water into a reactor, then add 5 g of γ-glycidyloxypropyltrimethoxysilane into the reactor, then add an appropriate amount of hydrochloric acid into the reactor, adjust the pH of the material in the reactor to 4, then add 8 g of nano zinc oxide into the reactor, stir evenly, then heat the material in the reactor to 90° C., react for 10 h under stirring and reflux conditions, filter after the reaction, wash the filter cake with ethanol, and dry to obtain modified nano zinc oxide.
[0039] (3) 5 g of the intermediate, 28 g of modified nano zinc oxide, 2.5 g of tetrabutylammonium bromide and 1500 mL of dichloromethane were added to the reactor, and the materials in the reactor were heated to 45° C. and stirred for 11 h. After the reaction was completed, the mixture was filtered, and the filter cake was washed with ethanol and dried to obtain a light stabilizer.
[0040] Comparative Example 1
[0041] The light aging resistant polyamide material of this comparative example is different from the light aging resistant polyamide material of Example 1 only in that the light stabilizer used in the light aging resistant polyamide material of this comparative example is the modified nano zinc oxide obtained in step (2) of preparing the light stabilizer in Example 1.
[0042] Comparative Example 2
[0043] The light aging resistant polyamide material of this comparative example is different from the light aging resistant polyamide material of Example 1 only in that the light stabilizer used in the light aging resistant polyamide material of this comparative example is vanillin.
[0044] Comparative Example 3
[0045] The light aging resistant polyamide material of this comparative example is different from the light aging resistant polyamide material of Example 1 only in that the light stabilizer used in the light aging resistant polyamide material of this comparative example is the intermediate obtained in step (1) of preparing the light stabilizer in Example 1.
[0046] Comparative Example 4
[0047] The light aging resistant polyamide material of this comparative example is different from the light aging resistant polyamide material of Example 1 only in that the light stabilizer used in the light aging resistant polyamide material of this comparative example is light stabilizer UV-3346, i.e. poly[N,N`-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine-CO-2,4-dichloro-6-morphine-1,3,5-triazine].
[0048] Effect example
[0049] In order to investigate the comprehensive performance of the light-resistant polyamide materials of each embodiment and comparative example, the light-resistant polyamide materials of each embodiment and comparative example were weighed according to the composition ratio and fed into the feeding port of a twin-screw extruder, melt-extruded at 265°C, stretched, cooled, and pelletized to obtain the light-resistant polyamide materials, and then the light-resistant polyamide materials were subjected to an aging test according to the method in the standard GB-T 16422.2-2014 "Plastic Laboratory Light Source Exposure Test Method", the aging time was 500h, and the tensile strength, flexural strength, impact strength and yellow index of the light-resistant polyamide materials before and after the aging test were tested respectively. Among them, the tensile strength was measured according to the method specified in the standard ISO527-2; the flexural strength was measured according to the method specified in the standard ISO178; the impact strength (notched impact strength of simply supported beam) was measured according to the method specified in the standard ISO179-1; the yellow index was measured according to the method specified in the standard HG / T 3862-2006 "Plastic Yellow Index Test Method". The measurement results of tensile strength, flexural strength, impact strength and yellowness index of the light aging resistant polyamide materials of various embodiments and comparative examples before and after the aging experiment are shown in Table 1.
[0050] Table 1 Tensile strength, flexural strength, impact strength and yellowness index of the light-resistant polyamide materials of each embodiment and comparative example before and after the aging experiment
[0051]
[0052] According to the experimental results in Table 1, a comparison chart of the tensile strength, flexural strength, impact strength and yellow index of the light aging resistant polyamide materials of each embodiment and comparative example before and after the aging experiment is drawn. The results are as follows: Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown. Among them, Figure 1 The figure is a comparison result of the tensile strength of the light aging resistant polyamide material of each embodiment and comparative example before and after the aging experiment; Figure 2 The figure is a comparison result of the bending strength of the light aging resistant polyamide material of each embodiment and comparative example before and after the aging experiment; Figure 3The figure is a comparison result of the impact strength of the light aging resistant polyamide material of each embodiment and comparative example before and after the aging experiment; Figure 4 The following is a comparison chart of the yellowness index of the light-resistant polyamide materials of each embodiment and comparative example before and after the aging experiment. Figure 1 , Figure 2 , Figure 3 , Figure 4 It can be seen that the light aging resistant polyamide material of the present invention has both good mechanical properties and anti-ultraviolet light aging properties.
Claims
1. A light aging resistant polyamide material, characterized in that: The invention comprises the following components in parts by weight: 30 to 45 parts of polyamide, 2 to 5 parts of toughening agent, 3 to 5 parts of glass fiber, and 1 to 1.5 parts of light stabilizer; The preparation method of the light stabilizer comprises the following steps: firstly subjecting melamine and excess 3-methoxy-4-hydroxybenzaldehyde to a Schiff base reaction to obtain an intermediate; The intermediate and epoxy-modified nano zinc oxide are then mixed and reacted at 85-95° C. under the action of a phase transfer catalyst to obtain a light stabilizer.
2. The light aging resistant polyamide material according to claim 1, characterized in that: The molar ratio of melamine to 3-methoxy-4-hydroxybenzaldehyde is 50:(300-400).
3. The light aging resistant polyamide material according to claim 1 or 2, characterized in that: The temperature of the Schiff base reaction is 70-80° C. and the reaction time is 6-10 hours.
4. The light aging resistant polyamide material according to claim 1, characterized in that: The preparation method of the epoxy-modified nano zinc oxide is as follows: nano zinc oxide and epoxy silane coupling agent in a mass ratio of (7-10):(5-6) are mixed in a solvent at a temperature of 85-95° C. for 8-12 hours; the solvent is mainly composed of ethanol and water in a mass ratio of 60:(20-30), and the pH of the solvent is 3.5-4.
5.
5. The light aging resistant polyamide material according to claim 4, characterized in that: The epoxy silane coupling agent is γ-glycidyloxypropyltrimethoxysilane.
6. The light aging resistant polyamide material according to claim 1, characterized in that: The mass ratio of the intermediate to the epoxy-modified nano zinc oxide is 5:(25-30).
7. The light aging resistant polyamide material according to claim 1 or 6, characterized in that: The mass ratio of the intermediate, epoxy-modified nano zinc oxide and phase transfer catalyst is 5:(25-30):(2-3).
8. The light aging resistant polyamide material according to claim 7, characterized in that: The phase transfer catalyst is tetrabutylammonium bromide.
9. The light aging resistant polyamide material according to claim 1 or 6, characterized in that: The time for the mixed reaction of the intermediate and the epoxy-modified nano zinc oxide is 10 to 12 hours.
10. The light aging resistant polyamide material according to claim 1, characterized in that: The polyamide is nylon 66, and the toughening agent is maleic anhydride grafted polyethylene.