Polyamide composite material as well as preparation method and application thereof

Abstract

The invention discloses a polyamide composite material as well as a preparation method and application thereof. The polyamide composite material comprises the following components in parts by weight: 75-92 parts of polyamide resin; 15 to 30 parts of brominated polystyrene; 8 to 16 parts of a phosphorus-based flame retardant; 0.2 to 2.0 parts of nano copper oxide; 0.2 to 2.0 parts of inorganic blue toner; and 0.2 to 2.0 parts of inorganic red toner. In a brominated flame-retardant polyamide material system, a phosphorus-based flame retardant is introduced as a flame-retardant synergist, and nano copper oxide is matched with the inorganic blue toner and the inorganic red toner to obtain a black product, so that carbon black powder is effectively replaced, the CTI value of the material is improved while high glow wire performance is obtained, and the flame-retardant polyamide material is suitable for industrial production. The solvent resistance of the system is improved, and the black polyamide composite material with high glowing filament, high CTI value and excellent solvent resistance is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a polyamide composite material and a preparation method and application thereof. BACKGROUND

[0002] Polyamide (nylon) has excellent mechanical properties, barrier properties, heat resistance, wear resistance, chemical corrosion resistance and other comprehensive properties, and its composite materials are widely used in mechanical manufacturing industry, household appliances, power tools, electronic appliances and transportation fields. Among them, bromine flame-retardant nylon is the preferred material for key components such as connector products due to its high glow wire performance, high efficiency flame retardancy and good color matching. The mainstream material scheme in the industry at present is to use traditional bromine flame retardant + antimony trioxide flame retardant system, however, it has the following problems: 1. The tracking index (CTI) is low (about 300V), which cannot meet the demand of higher CTI value of materials under the miniaturization trend of electrical products (the higher the CTI value, the smaller the allowed creepage distance and electrical clearance between metal pin needles); 2. The black dyeing demand conflicts with the CTI performance, and when low-cost inorganic carbon black is used as a black dyeing agent, it has a very obvious negative effect on CTI, making it more difficult to improve the CTI of black products; 3. The chemical solvent resistance is insufficient, and when the product is exposed to complex environments such as oil stains, detergents and refrigerants, abnormal phenomena such as color change or flame retardant precipitation that affect product quality are prone to occur.

[0003] Chinese patent application CN109021562A discloses a high-efficiency flame-retardant reinforced nylon composite material and a preparation method thereof, which utilizes the unique carbon-carbon double bond structure and epoxy group of itaconic acid epoxide compound to improve the compatibility of the matrix resin and inorganic additives and to improve the dispersion of the flame retardant in the matrix resin, thereby obtaining a high-efficiency flame-retardant scheme. However, the composite material obtained in this scheme does not have a particularly great breakthrough in tracking index CTI value, and the limit value can only reach 400V, which cannot meet the material application scenarios with higher CTI requirements, and it does not consider the black color matching problem.

[0004] There are relatively few studies in the prior art on how to consider the glow wire performance, CTI performance and organic solvent resistance of the composite material in the traditional bromine flame-retardant nylon system (especially black materials). Therefore, it is urgent to develop an innovative material scheme with balanced comprehensive performance to meet the use demand of black flame-retardant nylon materials for electronic appliances under the miniaturization trend. SUMMARY

[0005] In order to overcome the deficiencies of the prior art, the purpose of the present application is to provide a black polyamide composite material with high glow wire, high CTI value and excellent solvent resistance.

[0006] Another object of the present application is to provide a preparation method of the above-mentioned polyamide composite material.

[0007] The present application is realized by the following technical solutions: A polyamide composite material, by weight fraction, comprises the following components: Polyamide resin 75-92 parts; Brominated polystyrene 15-30 parts; Phosphorus-based flame retardant 8-16 parts; Nano copper oxide 0.2-2.0 parts; Inorganic blue color powder 0.2-2.0 parts; Inorganic red color powder 0.2-2.0 parts.

[0008] The weight fraction of the polyamide resin can be 75 parts, 78 parts, 80 parts, 82 parts, 84 parts, 86 parts, 88 parts or 92 parts, and specific point values between the above point values.

[0009] Preferably, the polyamide resin is selected from at least one of aliphatic polyamides. The aliphatic polyamide resin is a polymer having amide bonds (-NHCO-) in the main chain, including but not limited to the following: polyamide resins obtained by polycondensation of diamin and dicarboxylic acid, polyamide resins obtained by ring-opening polymerization of lactam, polyamide resins obtained by self-condensation of aminocarboxylic acid, and polyamide copolymers obtained by copolymerization of two or more units (monomers) constituting these polyamide resins. More preferably, the aliphatic polyamide is selected from at least one of nylon 6, nylon 66, nylon 610, nylon 612, nylon 1012, and nylon 12.

[0010] Preferably, the relative viscosity of the polyamide resin is 2.2-3.4; preferably 2.4-2.7. The relative viscosity is tested according to ISO 307-2007.

[0011] In the polyamide composite material of the present application, the mass content of the polyamide resin is not less than 55%.

[0012] The brominated polystyrene of the present application is a bromine-based organic flame retardant. The weight fraction of the brominated polystyrene can be 15 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts or 30 parts, and specific point values between the above point values.

[0013] Preferably, the bromine content of the brominated polystyrene is ≥ 60 wt%, more preferably 62 wt% - 68 wt%; the bromine content of the brominated polystyrene can be 62 wt%, 64 wt%, 66 wt% or 68 wt%, and specific point values between the above point values. The test method of bromine content is as follows: accurately weigh 10 mg of sample on a microanalytical balance, wrap it with ashless filter paper, clamp it on an alloy wire, add 0.1 mol / L sodium hydroxide solution 5 mL and 5% hydrogen peroxide 10 mL as the absorption liquid in the combustion bottle. Insert the oxygen pipe into the bottle and ventilate for 1-2 minutes, immediately ignite the tail of the filter paper on the wire, quickly insert it into the bottle, tighten the bottle plug, press the plug, carefully tilt the bottle to make the absorption liquid seal the bottle opening. At this time, the ignited filter paper and the sample are fully burned and decomposed in oxygen, shake the liquid in the bottle for about 1 minute, stand for about 30 minutes until the smoke in the bottle disappears completely. Carefully remove the plug, wash the plug, wire and bottle wall with 20 mL of ethanol, add 2-4 drops of bromophenol blue, neutralize with 0.5 mol / L nitric acid, make the solution change from blue to yellow, then add 10 drops of diphenyl azo carbazide indicator solution, titrate with mercury nitrate standard solution until the solution changes from yellow to blue purple. The blank test is carried out under the same conditions. The calculation result is as follows: Bromine content (%) = C'(V1-V2)'0.0799 / M x 100%, wherein: C - molar concentration of mercury nitrate standard solution, mol / L; V1 - volume of mercury nitrate standard solution consumed by the sample, mL; V2 - volume of mercury nitrate standard solution consumed by the blank, mL; M - sample mass, g; 0.0799 - milliequivalent of bromine.

[0014] Preferably, the weight average molecular weight of the brominated polystyrene is ≤ 5000; the weight average molecular weight of the brominated polystyrene can be 1000, 2000, 3000, 4000 or 5000, and specific point values between the above point values; more preferably, the weight average molecular weight of the brominated polystyrene is 1000-5000. The test of weight average molecular weight is based on GB / T 21864-2008, using tetrahydrofuran as the mobile phase to dissolve the brominated polystyrene, and using a condensation chromatograph equipped with a differential refractive index detector to detect the molecular weight of the sample.

[0015] The weight fraction of the phosphorus-based flame retardant can be 8 parts, 10 parts, 12 parts, 14 parts or 16 parts, and specific point values between the above point values.

[0016] Preferably, the phosphorus-based flame retardant is selected from at least one of organic phosphinic acid metal salt and polyphosphite; more preferably, the organic phosphinic acid metal salt includes aluminum diethyl phosphinate; the polyphosphite includes polyaluminum phosphate.

[0017] The color of the nano copper oxide will change significantly due to different particle sizes, which is mainly caused by quantum size effect and surface plasmon resonance effect. The nano copper oxide with a D50 particle size of 30-60 nm is preferred in the present application, which presents a deep brown or red-brown color. When combined with inorganic blue color powder and inorganic red color powder, a black product can be obtained. More preferably, the D50 particle size of the nano copper oxide is 35-50 nm. The D50 particle size test method is as follows: 1 g of nano copper oxide is placed in a 500 mL ethanol solution, ultrasonic vibration dispersion is carried out for 5 min, and then the suspension is taken into a Darwin particle size analyzer to obtain the D50 particle size value.

[0018] Preferably, the inorganic blue color powder is selected from at least one of ultramarine blue, cobalt blue and vanadium zirconium blue.

[0019] Preferably, the inorganic red color powder is selected from at least one of cerium sulfide red, cadmium red and iron oxide red.

[0020] The mass ratio of the nano copper oxide, inorganic blue color powder and inorganic red color powder is preferably 1:(0.5-4):1, and more preferably 1:(1-2):1.

[0021] According to the material performance requirements, the polyamide composite material of the present application can further comprise at least one of glass fiber and auxiliary agent; the auxiliary agent comprises at least one of antioxidant and lubricant.

[0022] Preferably, the polyamide composite material of the present application further comprises: glass fiber 0.5-40 parts and auxiliary agent 0.1-1 part by weight. The weight fraction of the glass fiber can be 0.5 parts, 10 parts, 20 parts, 30 parts or 40 parts, and specific point values between the above point values; the weight fraction of the auxiliary agent can be 0.1 parts, 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts or 1.0 parts, and specific point values between the above point values; preferably, the glass fiber is 20-40 parts and the auxiliary agent is 0.2-1 part.

[0023] The present application does not have special requirements for the type of glass fiber, and the glass fiber can be selected from any one or more of chopped strand A-glass fiber, E-glass fiber, C-glass fiber, D-glass fiber, S-glass fiber and R-glass fiber; the cross section of the glass fiber can be circular or non-circular. The skilled person can select the type of glass fiber according to the actual situation.

[0024] Suitable antioxidants include, but are not limited to, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexylenediamine; suitable lubricants include, but are not limited to, ethylene bis-stearamide. The present application does not have any particular requirements for the types and sources of antioxidants and lubricants, and the skilled person can select the types of antioxidants and lubricants to be added according to the actual situation.

[0025] The present application also provides a preparation method of the above-mentioned polyamide composite material, comprising the following steps: according to the proportion, each component is put into a mixer to mix uniformly to obtain a premix; the premix is put into a twin-screw extruder to perform melt mixing, and extrusion granulation is performed, wherein the temperature of the first region to the tenth region of the screw is set to be 75-85 DEG C, 170-190 DEG C, 250-270 DEG C, 250-270 DEG C, 240-260 DEG C, 240-260 DEG C, 240-260 DEG C, 240-260 DEG C, 240-260 DEG C, 250-270 DEG C, and the rotation speed range is 300 rpm-450 rpm, so that the polyamide composite material is prepared.

[0026] The present application also provides an application of the above-mentioned polyamide composite material in connector products. The connector products include household appliance connectors, industrial connectors and the like.

[0027] The present application has the following beneficial effects: In the bromine-based flame-retardant polyamide material system, on the one hand, by introducing a phosphorus-based flame retardant as a flame-retardant synergist, the negative influence of using traditional antimony trioxide on the CTI of the composite material is avoided, while the high glow wire performance of the bromine-based flame-retardant system is maintained; on the other hand, by using nano copper oxide in combination with inorganic blue color powder and inorganic red color powder, a black product can be obtained, effectively replacing the use of carbon black powder, which is conducive to improving the CTI value of the material, while maintaining the solvent resistance of the system, realizing a black polyamide composite material with high glow wire, high CTI value and excellent solvent resistance, which can meet the use requirements of black flame-retardant polyamide materials for electronic and electrical products under the miniaturization trend. DETAILED DESCRIPTION

[0028] The present application will be described in detail below in conjunction with specific examples. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be pointed out that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made. These all belong to the protection scope of the present application.

[0029] The raw materials used in the examples and comparative examples of the present application are described as follows, but are not limited to these materials: Polyamide resin 1: PA66, EP-158, the relative viscosity of the resin was 2.68 according to ISO307-2007, Huafeng Group Co., Ltd.; Polyamide resin 2: PA6, HY-2500A, the relative viscosity of the resin was 2.56 according to ISO307-2007, Jiangsu Haiyang Chemical Fiber Co., Ltd.; Brominated polystyrene 1: SAYTEX HP-5010PST, the bromine content was 63.23%, the weight average molecular weight was 4702, American Albemarle Co., Ltd.; Brominated polystyrene 2: SR-3010, the bromine content was 64.40%, the weight average molecular weight was 4950, Shandong Xuru New Material Co., Ltd.; Brominated polystyrene 3: XZ-6700, the bromine content was 64.52%, the weight average molecular weight was 237000, Shandong Brothers Chemical Co., Ltd.; Brominated polystyrene 4: BPS 7010, the bromine content was 63.82%, the weight average molecular weight was 195000, Shandong Tianyi Chemical Co., Ltd.; Phosphorus-based flame retardant 1: aluminum diethyl phosphinate, OP 1230, Clariant Chemical Co., Ltd.; Phosphorus-based flame retardant 2: polyaluminum phosphate, model PA2103, Shenzhen Ruishixing Technology Co., Ltd.; Nano copper oxide 1: D50 particle size 40 nm, JR-CU40, Xuancheng Jingrui New Material Co., Ltd.; Nano copper oxide 2: D50 particle size 50 nm, DXN-KD50, Nantong Daxin Nano Technology Co., Ltd.; Nano copper oxide 3: D50 particle size 58 nm, XD-CUQ60, Wuhu Xinda New Material Co., Ltd.; Nano copper oxide 4: D50 particle size 78 nm after screening of raw materials, JH-303, Shijiazhuang Jinghuang Technology Co., Ltd.; Nano copper oxide 5: D50 particle size 320 nm after screening of raw materials, JH-707, Shijiazhuang Jinghuang Technology Co., Ltd.; Inorganic blue color powder 1: Ultramarine blue 5008, BASF Chemical; Inorganic blue color powder 2: K6310, BASF Chemical; Inorganic red color powder 1: I4130S, Ranbar brand; Inorganic red color powder 2: FU-GS128, Guangdong Fenglin New Material (China); Carbon black: M717, Cabot Co., Ltd.; Aniline black: organic black toner, SUPER BLACK® NO. 2, Kunshan Qikai Chemical Co., Ltd. Anthraquinone blue: organic blue toner, L308, Kunshan Organic Chemical Factory Co., Ltd. Anthraquinone red: organic red toner, R218, Ningbo Longxin Fine Chemical Co., Ltd. Glass fiber: E glass fiber, brand ECS10-3.0-568H, surface modifier is silane coupling agent, China Jushi Co., Ltd. Antioxidant: N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine, commercially available; the same antioxidant was used in each parallel experiment. Lubricant: ethylene bis-stearamide, commercially available, the same lubricant was used in each parallel experiment.

[0030] Preparation method of the PVC / ABS alloy material of the examples and comparative examples: According to the proportion, each component was put into a mixer to mix uniformly to obtain a premix; the premix was put into a twin-screw extruder for melt mixing and extrusion granulation, wherein the temperature of the first to tenth zones of the screw was set to be 85°C, 190°C, 250°C, 250°C, 250°C, 260°C, 260°C, 260°C, 260°C, and 270°C, respectively, and the rotation speed range was 400 rpm, to prepare a polyamide composite material.

[0031] Related performance test methods: (1) Tracking Index of Electric Leakage CTI: tested according to GB / T4207-2012, sample size: 60mm *60mm*3.0mm.

[0032] (2) Glow Wire Ignition Temperature GWIT: tested according to standard GB / T 5169.13-2006, the test process required no flame (determined as passing when there was no flame, and determined as not passing regardless of the time length if there was a flame), sample size: 60mm*60mm*1.0mm.

[0033] (3) Solvent resistance test: 10g of plastic particles were respectively immersed in 100mL of ethanol solution (50% concentration), sodium hydroxide aqueous solution (2wt% concentration), and kitchen cleaner-dishwasher detergent, and after immersion at 50°C for 60min, the color change of the solution was observed. If the solution color did not change, the solvent resistance performance was OK; if the solution color changed from transparent to other colors, it indicated that the toner had a migration risk, and the solvent resistance performance was NG.

[0034] (4) Color Lab value test: According to the ISO 11664-4:2019 standard, the L value of the standard color plate was tested by USA X-Rite equipment. The L value of black product was required to be ≤30.

[0035] Table 1: Allocation ratio of each component (by weight fraction) and related performance test results of Examples 1-10 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Polyamide resin 1 85 90 85 85 85 85 85 85 85 Polyamide resin 2 78 Brominated polystyrene 1 25 18 25 25 25 25 25 Brominated polystyrene 2 30 Brominated polystyrene 3 25 Brominated polystyrene 4 25 Phosphorus-based flame retardant 1 10 15 10 10 10 10 10 10 10 Phosphorus-based flame retardant 2 12 Nano copper oxide 1 1 1 0.8 0.5 1.2 1 1 Nano copper oxide 2 2 1 Nano copper oxide 3 1 Inorganic blue colorant 1 1 2 1 1 1.4 2 0.6 1 1 Inorganic blue colorant 2 1.5 Inorganic red colorant 1 1 1 1 1 0.8 0.5 1.2 1 1 Inorganic red colorant 2 2 Glass fiber 30 30 / 30 30 30 30 30 30 30 Antioxidant 0.2 / 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Lubricant 0.2 / 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 CTI / V 500 550 450 475 450 500 425 425 375 400 GWIT / °C 775 760 750 760 760 775 760 765 770 760 Solvent resistance OK OK OK OK OK OK OK OK OK OK L value 27.0 27.6 28.2 27.4 27.7 28.0 29.2 29.8 29.7 29.1

[0036] Table 2: Allocation ratio of each component (by weight fraction) and related performance test results of Comparative Examples 1-6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Polyamide resin 1 85 85 85 85 85 85 Brominated polystyrene 1 25 25 25 25 25 25 Phosphorus-based flame retardant 1 10 10 10 10 10 10 Nano copper oxide 1 1 1 Nano copper oxide 4 1 Nano copper oxide 5 1 Inorganic blue colorant 1 1 1 1 Inorganic red colorant 1 1 1 1 Aniline black 3 Carbon black 3 Anthraquinone blue 1 Anthracene red 1 Glass fiber 30 30 30 30 30 30 Antioxidant 0.2 0.2 0.2 0.2 0.2 0.2 Lubricant 0.2 0.2 0.2 0.2 0.2 0.2 CTI / V 350 300 350 350 375 275 GWIT / °C 725 725 750 725 750 750 Solvent resistance OK OK NG NG NG OK L value 31.5 34.3 35.1 37.5 29.2 27.2 From the results of the above examples and comparative examples, it can be seen that, in the bromine-based flame-retardant polyamide material system, by introducing a phosphorus-based flame retardant as a flame-retardant synergist, and using nano-copper oxide in combination with inorganic blue color powder and inorganic red color powder, a required black polyamide composite material can be obtained, which has high glow wire ignition temperature (GWIT≥750℃), excellent electrical properties (CTI value≥375V) and excellent solvent resistance (no precipitation problem in ethanol solution, sodium hydroxide aqueous solution and cleaning agent).

[0037] Comparative Examples 1 / 2 use nano-copper oxide with a D50 particle size greater than 60 nm, and the L value is >30, which cannot obtain a black polyamide composite material, and the CTI value and GWIT of the material are significantly reduced.

[0038] Comparative Example 3 uses anthraquinone blue instead of inorganic blue color powder, and Comparative Example 4 uses anthraquinone red instead of inorganic red color powder, and the L value is >30, which cannot obtain a required black polyamide composite material, and the CTI value and GWIT of the material are significantly reduced.

[0039] Comparative Example 5 uses aniline black powder, which can obtain a black polyamide composite material, but the CTI value is <375V, and the solvent resistance is poor, and there is a precipitation problem in ethanol solution, sodium hydroxide aqueous solution and cleaning agent.

[0040] Comparative Example 6 uses carbon black powder, which can obtain very good dyeing effect, and the L value reaches 27.2, but the CTI value of the composite material is greatly reduced, which can only reach 275V.

Claims

1. A polyamide composite material, characterized in that, By weight, it includes the following components: 75-92 parts of polyamide resin; 15-30 parts of brominated polystyrene; 8-16 parts of phosphorus-based flame retardant; Nano copper oxide 0.2-2.0 parts; Inorganic blue pigment, 0.2-2.0 parts; Inorganic red pigment, 0.2-2.0 parts.

2. The polyamide composite material according to claim 1, characterized in that, The polyamide resin is selected from at least one of aliphatic polyamides; the aliphatic polyamide is selected from at least one of nylon 6, nylon 66, nylon 610, nylon 612, nylon 1012, and nylon 12.

3. The polyamide composite material according to claim 1, characterized in that, The weight-average molecular weight of the brominated polystyrene is ≤5000; preferably, the weight-average molecular weight of the brominated polystyrene is 1000-5000.

4. The polyamide composite material according to claim 1, characterized in that, The phosphorus-based flame retardant is selected from at least one of organic phosphonic acid metal salts and polyphosphites; the organic phosphonic acid metal salt includes aluminum diethylphosphonate; and the polyphosphite includes aluminum polyphosphite.

5. The polyamide composite material according to claim 1, characterized in that, The D50 particle size of the nano-copper oxide is 30nm-60nm, preferably 35nm-50nm.

6. The polyamide composite material according to claim 1, characterized in that, The inorganic blue pigment is selected from at least one of ultramarine blue, cobalt blue, and vanadium zirconium blue; the inorganic red pigment is selected from at least one of cerium sulfide red, cadmium red, and iron oxide red.

7. The polyamide composite material according to claim 1, characterized in that, The mass ratio of the nano copper oxide, inorganic blue pigment, and inorganic red pigment is 1:(0.5-4):1, preferably 1:(1-2):

1.

8. The polyamide composite material according to claim 1, characterized in that, It also includes at least one of glass fiber and additives; preferably, the glass fiber is 0.5-40 parts; the additives are 0.1-1 parts; the additives include at least one of antioxidants and lubricants.

9. A method for preparing the polyamide composite material according to any one of claims 1-8, characterized in that, The process includes the following steps: according to the formula, each component is put into a mixer and mixed evenly to obtain a premix; the premix is ​​put into a twin-screw extruder for melt mixing and extrusion granulation to prepare a polyamide composite material.

10. The use of the polyamide composite material according to any one of claims 1-8 in connector products.