An ultra-high glass fiber reinforced nitrogen-based flame retardant polyamide material and its preparation method

Abstract

A super high glass fiber reinforced nitrogen-based flame retardant polyamide material, characterized in that, by weight, it comprises the following raw materials: 40-50 parts of PA6 chips; 30-50 parts of chopped glass fibers; 5-10 parts of glass fiber powder; 8-15 parts of nitrogen-based flame retardant; 0.1-1.2 parts of stable additive; 0.3-0.8 parts of wetting agent; 0.1-0.7 parts of lubricant; 0.1-1 part of color powder. The obtained super high glass fiber reinforced nitrogen-based flame retardant polyamide material can be applied to low-voltage electrical components.

Description

Technical Field

[0001] The present invention relates to the manufacture of halogen-free flame-retardant polyamides, and particularly to a super-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, a preparation method thereof, and an application in the field of low-voltage electrical appliances. Background Art

[0002] Due to its low toxicity and good glow wire flame-retardant performance, nitrogen-based flame-retardant polyamide materials have been widely used in the low-voltage electrical appliance industry. However, due to the characteristics of the MCA flame-retardant mechanism and the superposition of the "wick effect", the upper limit of glass fiber reinforcement of glass fiber-reinforced MCA flame-retardant polyamide materials is limited to 35% and below, and there is almost no MCA flame-retardant polyamide material with 40% or more glass fiber reinforcement (the main reason is that the flame retardancy cannot pass the 960 °C glow wire).

[0003] For the bases and bases of AC contactors in low-voltage electrical appliances, due to their high flame retardancy, especially high rigid modulus requirements, only phosphorus-based flame-retardant or bromine-based flame-retardant glass fiber-reinforced nylon materials can be selected. However, the disadvantages of these two flame-retardant systems are also obvious: First, many current exported low-voltage electrical appliance materials have the requirement of "halogen-free and phosphorus-free". Second, the color of red phosphorus flame-retardant materials is severely restricted, and the cost pressure of bromine-based flame-retardant materials is huge due to the high price of flame retardants.

[0004] In recent years, the competition in the low-voltage electrical appliance market has become white-hot. For general electrical products, the requirement for controlling the raw material cost is becoming more and more strict. At the same time, the glow wire flame-retardant performance requirement for thinner low-voltage electrical appliance parts needs to pass the test at 960 degrees Celsius. Summary of the Invention

[0005] The present invention uses a twin-screw extruder with a specific aspect ratio (44:1). After the MCA and PA6 chips wet-treated with a liquid auxiliary agent are evenly stirred externally, they are fed from the main feeder. The chopped glass fibers are side-fed from the second barrel using a loss-in-weight feeder. The processing aids, color powder, and glass fiber powder are evenly stirred and then side-fed from the sixth barrel using a loss-in-weight feeder. Finally, a super-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material is prepared.

[0006] The present invention is achieved through the following technical solutions; a super-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, characterized in that, by weight, it comprises the following raw materials: PA6 chips 40 - 50; chopped glass fibers 30 - 50; glass fiber powder 5 - 10; nitrogen-based flame retardant 8 - 15; stable additive 0.1 - 1.2; wetting agent 0.3 - 0.8; lubricant 0.1 - 0.7; color powder 0.1 - 1.

[0007] In the above-mentioned ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, the relative viscosity index of the PA6 chips is 2.0 to 2.5 viscosity, preferably one or two of 2.0 viscosity and 2.45 viscosity, and most preferably the 2.0 viscosity PA6 chips of Haijing.

[0008] In the above-mentioned ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, the chopped glass fiber is a glass fiber with a chopped length of 3 to 5 mm and a single filament diameter of 9 to 13 μm. The preferred size is a chopped length of 3 mm and a single filament diameter of 10 μm. The most preferred glass fiber is DCS10-3.0-116A of Changhai.

[0009] In the above-mentioned ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, the nitrogen-based flame retardant is MCA. The shape of MCA is powdery. The preferred dosage range is 8 to 15%, and the most preferred dosage is 10%.

[0010] In the above-mentioned ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, the glass fiber powder is mainly ground from chopped glass fiber, and the retained length of the glass fiber powder is controlled at 0.20 mm to 0.40 mm.

[0011] In the above-mentioned ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, the stable additive mainly consists of one or more of N,N-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hexanediamine (antioxidant 1098), tris[2,4-di-tert-butylphenyl] phosphite (antioxidant 168), and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (antioxidant 1010). The preferred main antioxidant is 1010, the co-antioxidant is 1098, the addition ratio is 2:1, and the preferred addition amount is 0.6%.

[0012] In the above-mentioned ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, the wetting agent is a liquid auxiliary agent of the model POLINYL ST imported from Italy, which not only plays a wetting role but also gives the material a very good demolding effect. The preferred addition ratio is 0.3 to 0.8%, and the most preferred addition ratio is 0.6%.

[0013] In the above-mentioned ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, the lubricant is one or more of calcium stearate, modified ethylene bis-fatty acid amide (TAF), and ethylene-acrylic acid copolymer. The preferred one is TAF, and the preferred addition amount is 0.5%.

[0014] In the above-mentioned ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, the color powder is inorganic color powder and / or organic color powder, which is added according to actual color matching requirements.

[0015] The preparation method of the above-mentioned ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material is obtained by extrusion granulation with a twin-screw extruder. The length-diameter ratio of the screw of the twin-screw extruder is 44:1, and the main machine speed is 300 - 350 rpm. The temperature settings of each temperature zone of the twin-screw extruder are as follows: Zone 1: 220 ± 10 °C, Zones 2 to 4: 240 ± 10 °C, Zone 5: 225 ± 10 °C, Zone 6: 210 ± 10 °C, Zone 7: 205 ± 10 °C, Zones 8 to 11: 200 ± 10 °C, Die head: 225 ± 10 °C.

[0016] The chopped glass fiber is fed from the side of the second barrel, and the flame retardant, color powder, processing aid, glass fiber powder, etc. are added from the sixth barrel.

[0017] The obtained ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material can be applied to low-voltage electrical components.

[0018] Advantages of the present invention:

[0019] (1) The cost of the obtained material is reduced by 40 - 50% compared with bromine-based flame-retardant polyamide; due to the relatively high specific gravity, the single-piece raw material cost of low-voltage electrical products made of this material is reduced by 30 - 40%;

[0020] (2) Under the premise that the glow wire passes through at 1.0 mm and 960 °C, the highest addition ratio of short fibers and glass fiber powder can reach 45%, almost filling the gap in the existing market;

[0021] (3) The present invention achieves the effect of solving technical problems through the combined action of several factors such as adding a liquid wetting agent in the formula, side feeding of short fibers, side feeding of processing aids, and determination of the length-diameter ratio. Specific embodiments

[0022] First, use a high-speed stirring device to stir the color powder and processing aids evenly for 10 minutes; the glass fiber powder is added from the side of the sixth barrel. The PA6 chips are moistened with a liquid aid and then externally stirred with MCA and fed from the main feed. The chopped glass fiber is added from the side of the second barrel. Start the extruder and auxiliary equipment, and extrude, draw, and pelletize.

[0023] The present invention will be further described below in combination with Comparative Examples 1 - 3 and Examples 1 - 9.

[0024] Material Description Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 PA6 Chip 2.0 53 48 53 48 47.4 42.4 37.4 47.4 42.4 37.4 MCA (Powder) 10 10 10 10 10 10 10 10 10 10 Chopped Glass Fiber (Second Zone) 30 35 30 35 30 35 40 30 35 40 Glass Fiber Powder (Side Feeding) 0 0 5 5 10 10 10 10 10 10 Chopped Glass Fiber (Side Feeding) 5 5 0 0 0 0 0 0 0 0 Liquid Auxiliary Agent POLINYL ST 0 0 0 0 0.6 0.6 0.6 0.6 0.6 0.6 Processing Aid and Color Powder (Main Feeding) 2 2 2 2 2 2 2 0 0 0 Processing Aid and Color Powder (Side Feeding) 0 0 0 0 0 0 0 2 2 2

[0025] Test Items Testing Method Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 <![CDATA[Density (Method A) (g / cm 3 )]]> GB / T 1033.1 - 2008 1.45 1.52 1.45 1.52 1.52 1.60 1.66 1.52 1.60 1.66 Flexural Strength Mpa GB / T 9341 - 2008 125 134 112 124 125 138 155 145 170 180 Flexural Modulus Mpa GB / T 9341 - 2008 5750 5950 4800 5800 6600 7500 8800 9100 10200 11500 <![CDATA[Izod impact strength of simply supported beam (kJ / m 2 )]]> GB / T 1043.1 - 2008 30 31 30 29 29 30 29 33 34 33 Heat Deflection Temperature (°C) GB / T 9341 - 2008 165 170 135 145 160 168 173 185 197 200 Glow Wire Test (960°C / 1.0mm, s) GB / T 5169.11 - 2017 × × × × √ × × √ √ × Glow Wire Test (960°C / 1.6mm, s) GB / T 5169.11 - 2017 √ × √ √ √ √ × √ √ ×

[0026] Through the analysis of the data in Table 2: with 35% short glass fiber fed mainly and 10% glass powder fed laterally, with the assistance of the processing aid and color powder aid lateral feeding process, the material achieved very good mechanical properties and flame retardancy. However, when the addition amount of glass fiber was continuously increased, the flame retardancy deteriorated sharply, resulting in failure to pass the 960°C glow wire test.

[0027] Test Items Testing Method Example 8 30% Glass Fiber Reinforced Brominated Flame Retardant PA6 Comparative Example 2 Comparative Example 3 <![CDATA[Density (Method A) (g / cm 3 )]]> GB / T 1033.1 - 2008 1.60 1.585 1.60 1.60 Flexural Strength Mpa GB / T 9341 - 2008 170 185 165 168 Flexural Modulus Mpa GB / T 9341 - 2008 10200 10500 10000 10200 <![CDATA[Izod impact strength of simply supported beam (kJ / m 2 )]]> GB / T 1043.1 - 2008 34 50 33 35 Heat Deflection Temperature (°C) GB / T 9341 - 2008 197 205 197 197 Glow Wire Test (960°C / 1.0mm, s) GB / T 5169.11 - 2017 √ √ × × Glow Wire Test (960°C / 1.6mm, s) GB / T 5169.11 - 2017 √ √ √ √

[0028] The only difference between Comparative Example 2 and Example 8 in Table 3 is that the length-diameter ratio of the twin-screw is 48:1, and the twelfth zone is added, and the temperature parameter of the twelfth zone is set to: 200 ± 10°C.

[0029] The only difference between Comparative Example 3 and Example 8 in Table 3 is that the length-diameter ratio of the twin-screw is 40:1, and the eleventh zone is reduced.

[0030] Through the comparison of the data in Table 3, except that the non-notch impact property of the material of the present invention is significantly lower than that of the brominated flame retardant material, other properties are basically very close to those of the 30% glass fiber reinforced brominated flame retardant material.

[0031] The above embodiments are only for illustrating the present invention and not for limiting the present invention. Those skilled in the relevant technical fields can also make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention, which should be defined by each claim.

Claims

1. An ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material, characterized in that, By weight parts, it contains the following raw materials: PA6 chips: 40 - 50%; Chopped glass fiber: 30 - 50%; Glass fiber powder: 5 - 10%; Nitrogen-based flame retardant: 8 - 15%; Stabilizer: 0.1 - 1.2%; Wetting agent: 0.3 - 0.8%; Lubricant: 0.1 - 0.7%; Color powder: 0.1 - 1%; The wetting agent is a liquid auxiliary agent of model POLINYL ST imported from Italy; The nitrogen-based flame retardant is MCA; The ultra-high glass fiber reinforced nitrogen-based flame retardant polyamide material is obtained by extrusion granulation with a twin-screw extruder; the length-diameter ratio of the screw of the twin-screw extruder is 44:1, the main machine speed is 300 - 350 rpm, and the temperature settings of each temperature zone of the twin-screw extruder are as follows: Zone 1: 220 ± 10°C, Zones 2 to 4: 240 ± 10°C, Zone 5: 225 ± 10°C, Zone 6: 210 ± 10°C, Zone 7: 205 ± 10°C, Zones 8 to 11: 200 ± 10°C, Die head: 225 ± 10°C; the chopped glass fiber is fed in from the side of the second barrel, and the flame retardant, color powder, processing aids and glass fiber powder are added from the sixth barrel.

2. The ultra-high glass fiber reinforced nitrogen-based flame retardant polyamide material according to claim 1, wherein: The PA6 chips are PA6 chips with a relative viscosity index of 2.0 - 2.

5.

3. The super high glass fiber reinforced nitrogen-based flame retardant polyamide material according to claim 1, characterized in that: The chopped glass fiber is chopped glass fiber with a chopped length of 3 - 5 mm and a monofilament diameter of 10 - 13 μm.

4. The super-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material according to claim 1, characterized in that: The glass fiber powder is milled from chopped glass fiber.

5. The super-high glass fiber reinforced nitrogen-based flame retardant polyamide material according to claim 1, characterized in that: The stabilizer is one or more of antioxidant 1098, antioxidant 168, and antioxidant 1010.

6. The super-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material according to claim 1, characterized in that: The lubricant is one or more of calcium stearate, modified ethylene bis-fatty acid amide (TAF), and ethylene-acrylic acid copolymer.

7. An ultra-high glass fiber-reinforced nitrogen-based flame-retardant polyamide material according to claim 1, characterized in that: The color powder is inorganic color powder and / or organic color powder.

8. The preparation method of an ultra-high glass fiber reinforced nitrogen-based flame retardant polyamide material according to claim 1, which is obtained by extrusion granulation with a twin-screw extruder. The length-diameter ratio of the screw of the twin-screw extruder is 44:1, the main machine speed is 300 - 350 rpm, and the temperature settings of each temperature zone of the twin-screw extruder are as follows: Zone 1: 220 ± 10°C, Zones 2 to 4: 240 ± 10°C, Zone 5: 225 ± 10°C, Zone 6: 210 ± 10°C, Zone 7: 205 ± 10°C, Zones 8 to 11: 200 ± 10°C, Die head: 225 ± 10°C; the chopped glass fiber is fed in from the side of the second barrel, and the flame retardant, color powder, processing aids and glass fiber powder are added from the sixth barrel.