Long-term high-temperature thermo-oxidative aging resistant glass fiber reinforced PA6 and preparation method thereof

Abstract

The invention discloses long-term high-temperature thermo-oxidative aging resistant glass fiber reinforced PA6 and a preparation method thereof. The long-term high-temperature thermo-oxidative aging resistant glass fiber reinforced PA6 comprises the following raw materials in parts by weight: 48.7-88.7% of nylon resin; 10 to 50 percent of glass fiber; 0.4 to 1.9 percent of a long-acting high-temperature type antioxidant; 0-0.5% of common antioxidant, 0.5% of lubricant and 0.3% of color master batch. According to the invention, copper salt, polyamine and polyol are synergistically used, so that the long-term thermo-oxidative aging resistance of nylon at 180 DEG C can be greatly improved, and one or more nylon resins are introduced by adopting a blending means, so that the long-term thermo-oxidative aging resistance of the modified nylon composition can be further improved; and the service life of a nylon part under high-temperature harsh conditions such as the periphery of an automobile engine is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of functional engineering plastic modification, and specifically relates to a glass fiber reinforced PA6 resistant to long-term high temperature thermal oxidation aging and a preparation method thereof. Background Art

[0002] PA6 is an important engineering thermoplastic. It is widely used in the automotive, aerospace and other industrial fields due to its excellent mechanical properties, oil resistance and good ductility. However, some application fields require the long-term use temperature of the material to be higher, such as the long-term heat resistance temperature of the automobile engine hood is required to be 150°C, and even increased to 180°C. However, due to the strong polarity of the amide group (-NHCO-) ​​on the PA6 main chain, it is easily affected by environmental factors such as heat, oxygen, ultraviolet rays, and moisture, and a series of pyrolysis reactions occur to generate water, CO2, CO, hydrocarbons and a small amount of cyclopentanone, and the polymer main chain breaks, which in turn causes a decrease in relative molecular mass, a decrease in various performances, and a change in color. Especially when plastic parts are exposed to high temperatures for a long time, it will eventually lead to component failure, greatly shortening the service life of the material. Therefore, anti-aging measures must be taken to maintain the performance of the product after aging as much as possible.

[0003] To reduce the thermal oxidative degradation of PA6, stabilizers are necessary. The stabilization mechanism of typical antioxidants used for PA6 is known. When primary antioxidants such as phenolic antioxidants or secondary aromatic amines react with peroxy radicals to form less active free radicals and hydroperoxides, secondary antioxidants such as phosphites reduce the hydroperoxides to alcohols. However, the synergistic combination of primary and secondary antioxidants is often more effective for use below 120°C. When the temperature resistance requirement reaches 150°C, commonly used stabilizers are copper salts, which coordinate peroxy and hydroperoxy groups and may inactivate them through redox reactions. In addition, they can also initiate non-radical reactions of hydroperoxides with aldehydes. However, these traditional antioxidants have no further protective effect at aging temperatures of 150°C and above. Summary of the invention

[0004] In order to fill the gap in the prior art, the present invention provides a glass fiber reinforced PA6 with long-term high temperature resistance to thermal oxidation aging and a preparation method thereof, which expands the competitiveness of nylon materials in high temperature applications of 180°C or even higher.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned glass fiber reinforced PA6 that is resistant to long-term high temperature thermal oxidation aging.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A glass fiber reinforced PA6 with long-term high temperature thermal oxygen aging resistance, comprising the following raw materials in parts by weight:

[0008] 48.7 to 88.7 parts of nylon resin;

[0009] 10-50 parts of glass fiber;

[0010] 0.4-1.9 parts of long-acting high-temperature antioxidant;

[0011] Ordinary antioxidant 0-0.5 parts;

[0012] 0.5 parts of lubricant;

[0013] 0.3 parts of masterbatch.

[0014] in,

[0015] The PA6 resin is a 2.4-2.0 viscosity resin.

[0016] The common glass fiber has a chopped length of 3 mm, a fiber diameter of 0.10 μm, a silane-based sizing agent coated on the surface, and a flat glass fiber cross-section with a height of 7 μm and a width of 28 μm.

[0017] The long-acting high-temperature antioxidant is H318, and two synergistic compoundings of H318 and dipentaerythritol or triethylamine.

[0018] The common antioxidant is composed of the main antioxidant 1098 and the auxiliary antioxidant 168.

[0019] The lubricant is BIO-R05.

[0020] The masterbatch is carbon black masterbatch PA62015 / 6116.

[0021] The preparation method of the above-mentioned glass fiber reinforced PA6 with long-term high temperature thermal oxidation aging resistance comprises the following steps:

[0022] Step 1: Stir the dried nylon resin, antioxidant, lubricant and masterbatch at 40-100 rpm to obtain a mixture.

[0023] The second step: adding the mixture into the main feeding port of the twin-screw extruder, adding the glass fiber from the middle of the extruder through the side feeding device, and performing melt extrusion, cooling, pelletizing, and drying to obtain the high temperature heat-oxidative aging-resistant glass fiber reinforced PA6 composite material.

[0024] The extruder has an aspect ratio L / D=40, a temperature setting of 220° C.-250° C., and a screw speed of 350-500 rpm.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. The synergistic use of copper salts, polyols and polyamines was used to construct a long-lasting high-temperature antioxidant system, which significantly improved the performance retention rate of PA6 at 180°C. After 4000 hours of hot storage, the use of this long-lasting high-temperature antioxidant system made the performance retention rate as high as 70%, which is about 25% higher than the use of copper salt alone.

[0027] 2. Long carbon chain nylon PA610, copolymer nylon and MXD6 are introduced into the PA6 system. By adjusting the system compatibility, the mechanical properties of the composite nylon material and the performance retention rate under long-term high-temperature thermal aging are further improved, especially the addition of an appropriate amount of MXD6. DETAILED DESCRIPTION

[0028] PA6 resin, manufacturer: Sinopec; brand: YH400

[0029] PA610 resin, manufacturer: Dongchen; brand: Dongchen PA610

[0030] Copolymer nylon resin, manufacturer: Haiyang; brand: HYG-2500E

[0031] MXD6 resin, manufacturer: Huafeng, brand SN122

[0032] Flat glass fiber, manufacturer: Chongqing International; brand: 301HP-3-M4

[0033] Ordinary glass fiber, manufacturer: Chongqing International; brand: 301HP

[0034] Long-lasting high-temperature antioxidant: Manufacturer: Brueggemann, Ron, McLean, Brand: H318, dipentaerythritol, triethylamine

[0035] Primary antioxidant, manufacturer: Double Bond; brand: 1098

[0036] Secondary antioxidant, manufacturer: Double Bond; brand: 168

[0037] Lubricant, manufacturer: Hecai Chemical; brand: BIO-R05 Specific embodiments

[0039] Embodiment 1:

[0040] In terms of percentage, the raw materials include PA6 resin 68.7%; ordinary glass fiber 30%; primary antioxidant 0.25%; secondary antioxidant 0.25%; lubricant 0.5%; and masterbatch 0.3%.

[0041] The processing method is:

[0042] (1) Dry the PA6 resin in a vacuum circulation oven at 120°C for 6 hours to control the moisture content to less than 0.3%.

[0043] (2) The dried PA6 resin, the primary antioxidant, the secondary antioxidant, the lubricant, and the masterbatch are uniformly mixed in a high-speed mixer according to the formula ratio, and the mixture is added from the main feed of the twin-screw extruder. The glass fiber is added from the middle of the extruder through a side feeding device. After melt extrusion, cooling, pelletizing, and drying, the high temperature heat-oxidation aging-resistant glass fiber reinforced PA6 composite material is obtained.

[0044] Wherein, the aspect ratio of the twin-screw extruder is 40:1, the temperature range of the extruder is 0°C-100°C, the screw speed is set to 500rpm, and the processing temperatures of each section of the twin-screw extruder are: zone one temperature 0-100°C, zone two temperature 220-250°C, zone three temperature 235-245°C, zone four temperature 235-245°C, zone five temperature 235-245°C, zone six temperature 235-245°C, zone seven temperature 235-245°C, zone eight temperature 225-235°C, zone nine temperature 225-235°C, zone ten temperature 220-230°C, and the water tank temperature is 30-60°C.

[0045] Embodiment 2:

[0046] In terms of percentage, the raw materials include 68.8% PA6 resin; 30% ordinary glass fiber; 0.4% copper salt; 0.5% lubricant; and 0.3% masterbatch.

[0047] The processing method is the same as that in Example 1.

[0048] Embodiment 3:

[0049] According to percentage, the raw materials include PA6 resin 68.3%; ordinary glass fiber 30%; copper salt 0.4%; triethylamine 0.5%; lubricant 0.5%; and masterbatch 0.3%.

[0050] The processing method is the same as that in Example 1.

[0051] Embodiment 4:

[0052] In terms of percentage, the raw materials include 68.3% PA6 resin; 30% ordinary glass fiber; 0.4% copper salt; 0.5% dipentaerythritol; 0.5% lubricant; and 0.3% masterbatch.

[0053] The processing method is the same as that in Example 1.

[0054] Comparative Example 1:

[0055] According to percentage, the raw materials include 67.3% PA6 resin; 7% PA610 resin; 30% ordinary glass fiber; 0.4% copper salt; 1.5% triethylamine; 0.5% lubricant; and 0.3% masterbatch.

[0056] The processing method is the same as that in Example 1.

[0057] Comparative Example 2:

[0058] In terms of percentage, the raw materials include 67.3% PA6 resin, 7% PA610 resin, 30% ordinary glass fiber, 0.4% copper salt, 1.5% dipentaerythritol, 0.5% lubricant and 0.3% masterbatch.

[0059] The processing method is the same as that in Example 1.

[0060] Comparative Example 3:

[0061] In terms of percentage, the raw materials include 60.3% PA6 resin, 7% PA610 resin, 30% ordinary glass fiber, 0.4% copper salt, 1.5% dipentaerythritol, 0.5% lubricant and 0.3% masterbatch.

[0062] The processing method is the same as that in Example 1.

[0063] Comparative Example 4:

[0064] In terms of percentage, the raw materials include 60.3% PA6 resin; 7% copolymer nylon resin; 30% ordinary glass fiber; 0.4% copper salt; 1.5% dipentaerythritol; 0.5% lubricant; and 0.3% masterbatch.

[0065] The processing method is the same as that in Example 1.

[0066] Comparative Example 5:

[0067] In terms of percentage, the raw materials include 60.3% PA6 resin, 7% MXD6 resin, 30% ordinary glass fiber, 0.4% copper salt, 1.5% dipentaerythritol, 0.5% lubricant and 0.3% masterbatch.

[0068] The processing method is the same as that in Example 1.

[0069] Comparative Example 6:

[0070] In terms of percentage, the raw materials include 50.3% PA6 resin; 17% MXD6 resin; 30% ordinary glass fiber; 0.4% copper salt; 1.5% dipentaerythritol; 0.5% lubricant; and 0.3% masterbatch.

[0071] The processing method is the same as that in Example 1.

[0072] Comparative Example 7:

[0073] In terms of percentage, the raw materials include 67.3% PA6 resin; 30% flat glass fiber; 0.4% copper salt; 1.5% dipentaerythritol; 0.5% lubricant; and 0.3% masterbatch.

[0074] The processing method is the same as that in Example 1.

[0075] Comparative Example 8:

[0076] In terms of percentage, the raw materials include 87.3% PA6 resin; 30% flat glass fiber; 0.4% copper salt; 1.5% dipentaerythritol; 0.5% lubricant; and 0.3% masterbatch.

[0077] The processing method is the same as that in Example 1.

[0078] Comparative Example 9:

[0079] In terms of percentage, the raw materials include 47.3% PA6 resin; 30% flat glass fiber; 0.4% copper salt; 1.5% dipentaerythritol; 0.5% lubricant; and 0.3% masterbatch.

[0080] The processing method is the same as that in Example 1.

[0081] The above embodiments and comparative examples were injection molded into standard specimens (specimen dimensions: 170*10*4mm, 80*10*4mm) and placed in a 180°C thermal oxygen aging oven. A group of specimens were taken out every 1000 hours for testing. The test items are shown in Table 2.

[0082] Table 1 List of experimental groups

[0083]

[0084] Table 2 List of test results of each experimental group

[0085]

[0086] The comparison of Examples 1 to 2 in Table 2 shows that conventional hindered phenol and phosphite antioxidants have poorer performance retention effects than copper salts at a high temperature of 180°C, which is particularly obvious after 2000 hours. Comparison of Examples 2 to 4 shows that the synergistic use of triethylamine, dipentaerythritol and copper salts all improves the mechanical property retention rate of PA6+GF30 at a high temperature of 180°C, among which the synergistic system of dipentaerythritol and copper salt is more obvious, and the high-temperature thermal aging effect is the best. In Example 3 and Comparative Example 1, increasing the content of triethylamine is beneficial to the improvement of the retention rate to a certain extent, but compared with Example 4 and Comparative Example 2, the increase in the content of dipentaerythritol is more significant in improving the retention rate.

[0087] Comparison between Example 4 and Comparative Examples 3 to 6 shows that the introduction of PA610, copolymerized nylon, and MXD6 can effectively improve the long-term high-temperature thermal aging performance of PA6+GF30. When the ratio of MXD6 to PA6 is increased from 1:9 to 1:3, the thermal aging performance of the system is further improved, which is attributed to the good heat resistance of MXD6 itself. Example 4 and Comparative Example 7 show that the uniform dispersion of flat glass fibers in the system and good interfacial compatibility are beneficial to the high-temperature thermal oxidation aging performance of the system relative to ordinary glass fibers. In addition, Example 4 and Comparative Examples 8 to 9 also show that in this long-term high-temperature antioxidant system, the appropriate glass fiber content will optimize the high-temperature resistance of the material. Therefore, through the synergistic use of the above-mentioned antioxidant system and the blending and screening of nylon resins, it can be achieved that the glass fiber reinforced PA6 system can maintain a high retention rate of more than 50% after being placed at 180°C for 4000h.

[0088] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A glass fiber reinforced PA6 with long-term high temperature thermal oxidation aging resistance, characterized by: The invention is composed of the following raw materials in parts by weight: 48.7-88.7 parts of nylon resin; 10-50 parts of glass fiber; 0.4-1.9 parts of long-acting high-temperature antioxidant; 0-0.5 parts of common antioxidant; 0.5 parts of lubricant; and 0.3 parts of masterbatch.

2. The glass fiber reinforced PA6 with long-term high temperature thermal oxidation aging resistance according to claim 1, characterized in that: The nylon resin includes one or a mixture of PA6, PA612, copolymerized nylon, and MXD6.

3. The glass fiber reinforced PA6 with long-term high temperature thermal oxidation aging resistance according to claim 1, characterized in that: The glass fiber is divided into ordinary glass fiber and flat glass fiber, wherein ordinary glass fiber refers to chopped strands, with a chopped length of 3mm, a fiber diameter of 0.10μm, and a silane-based sizing agent coated on the surface, which is at least one of 301HP and 116H. The flat glass fiber 301HP-3-M4 has a cross-sectional height of 4-10μm and a cross-sectional width of 20-40μm.

4. The glass fiber reinforced PA6 with long-term high temperature thermal oxidation aging resistance according to claim 1, characterized in that: The long-acting high-temperature antioxidant is one of the copper salts H318, H3386 and BTN, used in synergy with the polyol dipentaerythritol and the polyamine triethylamine.

5. The glass fiber reinforced PA6 with long-term high temperature thermal oxidation aging resistance according to claim 1, characterized in that: The common antioxidants are divided into primary antioxidants and secondary antioxidants. The primary antioxidant is at least one of 1098, 1010, and 2450, and the secondary antioxidant is at least one of 168 and 9228.

6. The glass fiber reinforced PA6 with long-term high temperature thermal oxidation aging resistance according to claim 1, characterized in that: The lubricant is at least one of OP wax, BIO-R05, silicone powder and 816A.

7. The glass fiber reinforced PA6 with long-term high temperature thermal oxidation aging resistance according to claim 1, characterized in that: The color masterbatch is a kind of carbon black and aniline black masterbatch.

8. The method for preparing glass fiber reinforced PA6 with long-term high temperature thermal oxidation aging resistance according to any one of claims 1 to 7, characterized in that: The following steps are involved: The first step: stirring the dried nylon resin, antioxidant, lubricant and masterbatch at 40-100 rpm to obtain a mixture; The second step: adding the mixture into the main feeding port of the twin-screw extruder, adding the glass fiber from the middle of the extruder through the side feeding device, and performing melt extrusion, cooling, pelletizing, and drying to obtain the high temperature heat-oxidative aging-resistant glass fiber reinforced PA6 composite material.

9. The method for preparing a glass fiber reinforced PA6 with long-term high temperature thermal oxidation aging resistance as claimed in claim 8, characterized in that: The extruder has an aspect ratio L / D=40, a temperature setting of 220° C.-250° C., and a screw speed of 350-500 rpm.

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