Preparation method and application of glass fiber reinforced high-temperature-resistant bio-based nylon 5T / 56 composite material

Abstract

The invention relates to a preparation method and application of a glass fiber reinforced high-temperature-resistant bio-based nylon 5T / 56 composite material, and belongs to the technical field of high polymer materials, the composite material with excellent physical properties and chemical stability can be prepared by adding glass fibers subjected to surface treatment into PA5T / 56 resin according to a reasonable proportion and matching with a reasonable auxiliary agent, the material performance is excellent, and the application range is wide. The preparation process has proper parameters and obvious effects.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and particularly relates to nylon 5T / 56, and specifically relates to a glass fiber reinforced high-temperature-resistant bio-based nylon 5T / 56 composite material preparation method and application. BACKGROUND

[0002] Polyamide (PA), commonly known as nylon, is widely used in military, industry, machinery, medical treatment and other fields due to its excellent toughness, wear resistance, self-lubricating property, oil resistance, chemical resistance, antibacterial property, non-toxicity and easy coloring, and is the first of the five engineering plastics. Among various nylon varieties, PA66, as a representative of aliphatic amide, becomes one of the most used engineering plastics due to its outstanding strength, high-temperature resistance and fatigue resistance, and its products occupy an important position in the fields of automobile engine accessories, electronic appliances, railway track transportation and the like.

[0003] With the rapid development of electronic appliances and automobile industry, more stringent requirements are put forward for the performance of engineering plastics. For example, high-end electronic appliance connectors (board end connectors) require that the materials have high heat resistance, solder resistance, surface mount (SMT) adaptability, high dimensional accuracy and good electrical insulation, and automobile engine key components (sensors, ignition coils, cooling pipeline joints) require that the materials can withstand high temperature for a long time, are resistant to oil and creep, and maintain excellent dimensional stability and chemical stability.

[0004] The above high performance requirements have significantly exceeded the physical and chemical performance bearing range of traditional aliphatic nylon materials represented by PA66.

[0005] In order to break through the performance bottleneck of aliphatic nylon, semi-aromatic high-temperature nylon is developed by introducing rigid benzene ring structure into the molecular chain. The introduction of benzene ring effectively increases the rigidity of the molecular chain, limits the activity of the chain segment, and thus endows the material with higher glass transition temperature T g and melting point T m , more excellent chemical resistance, especially after being reinforced by glass fiber, can have ultra-high heat resistance, extremely low moisture absorption, excellent dimensional stability, extremely high strength and rigidity, excellent chemical resistance and solder resistance. At the same time, semi-aromatic nylon retains the easy processing characteristics of high molecular materials, and can realize grade diversification and performance customization through physical blending, chemical modification and other means to meet the specific needs of different products, so that it becomes an ideal engineering plastic in the fields of high-end electronic appliances and automobiles.

[0006] The typical representative of semi-aromatic widely used at present, such as PA6T / 66, its raw material is mainly derived from petroleum resources. The consumption of petroleum resources and the environmental problems caused by its exploitation and processing are contrary to the concept of sustainable development. Therefore, the development of bio-based nylon products based on renewable resources has become an important development trend in the field of materials. Among them, pentanediamine as a key bio-based monomer can be obtained from renewable plant resources such as starch and sugar through specific biological conversion processes such as microbial fermentation. By using bio-based pentanediamine and aromatic diacid copolymerization or with adipic acid copolymerization, bio-based semi-aromatic high-temperature resistant nylon base material such as PA5T can be synthesized. Through corresponding blending modification, its application field can be expanded, and engineering parts meeting the requirements of high-end fields such as electronic appliances, automobile industry and aviation can be prepared.

[0007] There have been some related researches on bio-based nylon in the prior art. The invention patent with publication number CN109957239A proposes a thermoplastic reinforced bio-based PA56 / PA66 alloy and its preparation method, which aims to meet the demand for environmentally friendly materials in the field of electronic appliances and household appliances. The invention patent with publication number CN114907563B proposes a flame-retardant modified PA56 / 5T material and its preparation method and application, which solves the problem of easy separation of halogen-free flame-retardant products. However, the above-mentioned bio-based materials belong to the category of general nylon. The PA56 / 66 alloy is mainly based on aliphatic monomers pentanediamine and adipic acid, and its heat resistance and rigidity cannot reach the level of semi-aromatic high-temperature nylon in essence. Although the flame-retardant modified PA56 / 5T introduces 5T units with cold and hot partial aromatic structure, the overall performance, especially the long-term heat resistance, rigidity and dimensional stability at high temperature, still lags behind the petroleum-based semi-aromatic high-temperature nylon such as PA6T / PA9T / PA10T, and it is difficult to meet the long-term use requirements in harsh environments with extremely high heat resistance and rigidity requirements, such as high-temperature areas in automobile engine compartments and high-precision high-temperature SMT processes. Therefore, they do not belong to special high-temperature nylon.

[0008] In summary, the core challenge faced by the current nylon material field is that existing high-performance modified engineering plastics often rely on non-renewable petroleum resources, while existing bio-based nylon materials have environmental advantages, but their key performance such as heat resistance and high-temperature rigidity still cannot meet the requirements of special high-temperature engineering plastics, and they cannot completely replace petroleum-based high-temperature nylon in the most demanding high-end engineering fields.

[0009] With the development of high-end manufacturing, the demand for high-function, high-regeneration and excellent processing performance of special engineering plastics applied to extreme environments is increasingly urgent. Therefore, the development of bio-based special high-temperature resistant nylon modified materials with high-functionality such as ultra-high heat resistance, high rigidity, excellent dimensional stability, and based on renewable resources, environmental sustainability, and excellent processing performance has become a key technical problem that needs to be solved urgently. SUMMARY

[0010] In order to solve the problems of the prior art, the application provides a high-function bio-based glass fiber reinforced nylon 5T / 56 composite material with excellent comprehensive performance, high rigidity, high heat resistance, solvent resistance, good processing performance, high gloss, low warping, and dimensional stability.

[0011] The technical problem to be solved by the application is solved by the following technical scheme:

[0012] A glass fiber reinforced high-temperature resistant bio-based nylon 5T / 56 composite material is prepared by the following weight percentage of raw materials:

[0013] PA5T / 56 resin 50%-80%, glass fiber 20%-40%, antioxidant 0.1%-1%, nucleating agent 0.1%-0.5%, lubricant 0.1%-1%, dispersant 0.1%-1%, black masterbatch 1%-2%.

[0014] Among them: PA5T / 56 resin is a copolymer of p-xylylenediamine terephthalic acid and p-xylylenediamine adipic acid, the ratio of 5T to 56 is (0.5-0.9):(0.1-0.5), and the relative viscosity is 2.0-2.6.

[0015] The glass fiber is an alkali-free chopped glass fiber, the single filament diameter is 8-15 μm, the chopped length is 3-6 mm, and the surface is treated with a silane coupling agent. The main function of the glass fiber is to reinforce the material. Compared with pure resin, the load of external stress is changed from the matrix resin to the glass fiber, which greatly improves the strength and modulus of the composite material. At the same time, the surface wetting agent of the glass fiber acts as a bridge between inorganic and organic substances, limiting the activity of nylon molecular chains, improving the fatigue and creep resistance of the material, improving the heat resistance, and making the heat distortion temperature HDT of the PA5T / 56 composite material > 260℃, meeting the surface mounting treatment of the board end connector reflow soldering, and being used at 150℃ for a long time, meeting the long-term use of the product in the high-temperature environment of the automobile engine compartment.

[0016] The glass fiber is a mixture of one or more of Chongqing International 301HP, Taishan Glass Fiber T435TM, and Jushi Glass Fiber 568H.

[0017] The antioxidant is one or more of the following mixed: N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexylenediamine (antioxidant 1098), tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester (antioxidant 1010), 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (antioxidant AO-80), bis(2,4-dicumylphenyl)pentaerythritol-diphosphite (antioxidant Revonox 608), tris(2,4-di-tert-butylphenyl)phosphite (antioxidant 168). The preferred antioxidant is a mixture of antioxidant 1098 and antioxidant Revonox 608. Hindered phenols, semi-hindered phenols, primary antioxidants, inhibit the progress of chain reactions mainly by capturing free radicals, secondary antioxidants mainly reduce the formation of free radicals by decomposing hydroperoxides, reducing chain branching reactions, and the synergistic effect of primary antioxidants and secondary antioxidants improves the heat-oxidative aging resistance of polymers during processing and storage.

[0018] The nucleating agent is one or more of the following mixed: P22, CAV102, ultrafine talc, organic montmorillonite. The main role of the nucleating agent is to increase the crystallization temperature, accelerate the crystallization rate, and shorten the molding cycle. At the same time, it forms fine and uniform spherulites, reduces the concentration of internal stress and warping, and small and uniform spherulites help to obtain smooth and high-gloss products. Inorganic nucleating agents and organic nucleating agents have better synergistic effect when compounded.

[0019] The lubricant is one or more of the following mixed: calcium stearate, lithium stearate, P130, pentaerythritol stearate, oxidized polyethylene wax, partially saponified ester wax (montan wax), montanic acid wax, N,N'-ethylene bis-stearamide (EBS), silicone master batch. It is used to reduce the shear friction between the molten polymer and the machine surface during plastic extrusion and injection molding, and to reduce the internal viscous resistance of the molten polymer. Preferably, the lubricant is a mixture of lithium stearate and P130. The two lubricants are compounded, the frictional resistance of the external mold surface is reduced, and at the same time the internal molecular chain viscoelastic resistance is reduced, the flow forming property is improved, the product surface is more glossy, and EBS is a macromolecule with active functional group end group structure, which provides flow while assisting the dispersion of glass fibers.

[0020] The dispersant is a mixture of one or more of a hyperbranched polyester (HBP), a hyperbranched high-temperature resistant dispersant, an N,N'-ethylenebisstearamide modified graft, and a dendritic branched resin. Preferably, the dispersant is a mixture of HBP-160, CYD-816A, and TAF-A. Compared to amino-terminated, hydroxyl-terminated, and epoxy-based polymers, carboxyl-terminated hyperbranched polyesters are easily adsorbed on the surface of the material in solid form. Their end groups react with the amino groups of the resin, increasing the dispersion of the glass fiber in the resin matrix, enabling better interfacial bonding between the glass fiber and the matrix, and evenly dispersing the stress transfer. Its high degree of branching, low viscosity, and lack of entanglement between molecules allow it to enter the matrix resin molecular chains during processing, reducing the viscous flow resistance between the molecular chains and improving the overall fluidity and dispersibility of the material.

[0021] The black masterbatch was a commercially available product, Cabot 2718.

[0022] The method for preparing the composite material comprises the following steps:

[0023] The PA5T / 56 resin was dried at 110 °C for 3 h;

[0024] Weigh all the raw materials except glass fiber and mix at low speed for 3-5 minutes;

[0025] The mixed raw materials were added to the main feeding bin of the extruder, and the glass fiber was added from the side feeding bin, melt-mixed and extruded. The temperatures of each temperature zone of the extruder were: 260°C for the first section, 330°C for the second section, 330°C for the third section, 320°C for the fourth section, 320°C for the fifth section, 310°C for the sixth section, 300°C for the seventh section, 300°C for the eighth section, 310°C for the ninth section, and 320°C for the die head. The screw speed was 380-400r / min, and the vacuum degree was <-0.08MPa.

[0026] The molten material is extruded into strips through the die of the extruder. The strips are passed through a water trough for a length of 20 cm. After absorbing the moisture on the surface of the strips, the material is cut to obtain the product composite material particles. The product is cylindrical particles with neat cross-section.

[0027] The glass fiber is added from the side feeding bin of the fourth stage of the extruder.

[0028] In the present invention, the glass fiber reinforced high-temperature resistant bio-based nylon 5T / 56 composite material and the product prepared by the above preparation method can be applied to electronic and electrical connectors and automobile engine accessories.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] (1) The copolymerization ratio of PA5T / 56 in the raw material of the present application is (0.5-0.9):(0.1-0.5), a high proportion of aromatic monomers is used, which significantly improves the rigidity of the molecular chain, greatly improves the glass transition temperature, and the glass fiber reinforcement improves the heat distortion temperature, so that the heat resistance of the product is improved by 10%;

[0031] (2) In the raw material of the present application, the alkali-free short-cut glass fiber treated with silane coupling agent improves the interfacial bonding force by 40% compared with the unmodified conventional glass fiber, reduces the fiber pulling phenomenon, and improves the tensile strength by 15%;

[0032] (3) In the raw material of the present application, the hyperbranched polyester / high-temperature resistant dispersant solves the problem of thermal decomposition of traditional dispersants in high-temperature processing, and improves the dispersion uniformity of glass fiber in the matrix, and the floating fiber rate is reduced by 50%;

[0033] (4) In the raw material of the present application, the antioxidant is selected by using hindered phenolic and phosphate compounds, which synergistically inhibits high-temperature oxidation, so that the strength retention rate of the material after aging at 150℃ / 1500h is still not less than 85%;

[0034] (5) In the raw material of the present application, the nucleating agent accelerates the crystallization rate, and the lubricant reduces the melt viscosity. The combination of nucleating agent and lubricant, the nucleating agent accelerates the crystallization rate, shortens the molding cycle, forms small and uniform spherulites, reduces residual stress, and improves the surface gloss of the product. Lubricant reduces the demolding resistance, reduces the processing temperature, reduces the viscous resistance between molecular chains, and the lubricant is compounded with two kinds, which has the effect of external demolding and internal lubrication;

[0035] (6) In the preparation method of the present application, the second and third high-temperature zones are set to 330℃, which breaks through the upper limit of the processing temperature of conventional bio-based nylon 310℃, significantly reduces the melt viscosity, improves the glass fiber wettability, and meets the high melting point requirement of bio-based PA5T / 56;

[0036] (7) In the preparation method of the present application, the glass fiber is added in the fourth segment, instead of the second and third segments or the fifth and sixth segments of the conventional melting segment, at this time the resin has been fully melted but has not reached the critical point of thermal decomposition, which ensures the uniformity of glass fiber dispersion and reduces fiber breakage, balances the contradiction between melting and degradation, and optimizes the interfacial bonding. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The photo of the product particles prepared in the present application;

[0038] Figure 2 The mechanical property columnar comparison chart of the product prepared in the present application;

[0039] Figure 3A comparison chart of the heat distortion temperature (HDT) curves of the products prepared in the present application. DETAILED DESCRIPTION

[0040] The application will be further described with reference to the accompanying drawings and specific preferred embodiments, but the scope of protection of the application is not limited thereby.

[0041] Example 1

[0042] Preparation of a glass fiber reinforced PA5T / 56 composite material, comprising the following steps:

[0043] S1: Preparation

[0044] S1-1: Synthesis of PA5T / 56 resin:

[0045] (i) Raw material ratio control: The molar ratio of pentanediamine to terephthalic acid (5T) and adipic acid (56) is strictly controlled within the range of (0.5-0.9):(0.1-0.5), and the error is controlled within ±0.5% by high-precision metering pump feeding;

[0046] (ii) Polymerization process: In the prepolymerization stage, the reaction temperature is 220-240℃, the pressure is 1.0-1.5MPa, the reaction time is 2-3h, and the vacuum degree is gradually increased to-0.05MPa; in the polycondensation stage, the temperature is 260-280℃, the vacuum degree is less than-0.09MPa, the stirring rate is 100-150r / min, and the reaction is carried out until the relative viscosity reaches 2.0-2.6;

[0047] (iii) Viscosity control method: 0.1-0.3% acetic acid is added as a molecular weight regulator, and the reaction time and vacuum degree are adjusted in real time according to the target viscosity.

[0048] S1-2: Extrusion process design:

[0049] Temperature gradient design: 260℃ in the first stage (charging stage) to keep the resin particles soft and avoid wall sticking;

[0050] 330℃ in the second stage (melting stage) which is higher than the melting point of PA5T / 56 (313℃) to ensure complete melting;

[0051] 330℃ in the third stage (mixing stage) to ensure that the resin is fully melted and that the glass fiber is fully infiltrated when added in the fourth stage;

[0052] 320℃ in the fourth stage (side feeding stage) to prevent local overheating degradation when the glass fiber is added;

[0053] 290-320℃ in the fifth to ninth stages (homogenization stage) to promote uniform shearing and material dispersion, and 320℃ in the die head to ensure stable extrusion.

[0054] S2: Raw material preparation

[0055] PA5T / 56 resin: pentanediamine terephthalate and pentanediamine adipate copolymer, 5T / 56 molar ratio (0.5-0.9):(0.1-0.5), relative viscosity 2.0-2.6, dried at 110°C in a moisture drying oven for 3h before use, water content controlled below 0.05%.

[0056] Glass fiber: single filament diameter 8-15μm, chopped length 3-6mm, surface treated with silane coupling agent KH-550.

[0057] Auxiliary agent: antioxidant, nucleating agent, lubricant, dispersant, black masterbatch.

[0058] S3: Mixing

[0059] Equipment: 100L high-speed mixer SHR-100A, variable frequency speed regulation, purchased from Zhangjiagang Yunfan Machinery Co., Ltd.

[0060] Procedure: first add PA5T / 56 resin into the mixer, run at low speed of 300r / min;

[0061] Add antioxidant, nucleating agent, lubricant, dispersant in sequence, with an interval of 30s for each addition;

[0062] After the addition is completed, increase the speed to 800r / min and mix for 3min, then reduce the speed to 300r / min and mix for 2min;

[0063] Finally, add black masterbatch, mix for 1min, then discharge, and pass the mixture through a 10-mesh screen with a pass rate of 96%.

[0064] S4: Extrusion molding

[0065] Equipment: twin-screw extruder TSE-40A, length-diameter ratio 40:1, purchased from Nanjing Ruia Extrusion Machinery Manufacturing Co., Ltd.

[0066] Process parameters:

[0067] Temperature of each zone: 260°C for the first stage, 330°C for the second stage, 330°C for the third stage, 320°C for the fourth stage, 320°C for the fifth stage, 310°C for the sixth stage, 300°C for the seventh stage, 300°C for the eighth stage, 310°C for the ninth stage, and 320°C for the die head, with an actual temperature deviation of no more than ±5°C from the set value;

[0068] Screw speed: 380-400r / min, with a melt pressure maintained at 8-12MPa;

[0069] Feeding method: the mixture is added from the main feeding bin, and the glass fiber is added from the fourth stage side feeding bin;

[0070] Vacuum: -0.085 MPa, three-stage water ring vacuum pump was used to remove volatile matter.

[0071] S5: Cooling and pelletizing

[0072] Water tank temperature: 20℃, length of the strip passing through water 20cm;

[0073] Pulling speed: 10m / min, matching with the extrusion rate;

[0074] Pelletizing parameters: speed of pelletizer 2000r / min, distance between cutter and die 5mm, the diameter of the pellets was 3±0.2mm, the length was 3.5±0.3mm, the pellets were as shown in Figure 1 ;

[0075] Post-processing: grading by vibrating screen, the proportion of qualified pellets was 98.5%, the unqualified pellets were recycled.

[0076] Example 2

[0077] Referring to the process of Example 1, different raw materials and additive dosages were used to set up different experimental groups and control groups to show the technical effects.

[0078] S1: Preparation of raw materials and additives

[0079] PA5T / 56 resin: SH406, viscosity 2.4, medium viscosity, melting point 313℃, glass transition temperature 95℃, heat distortion temperature HDT 102℃, purchased from Sichuan Shenghong in China

[0080] PA6T / 66 resin: SH401, viscosity 2.1, medium viscosity, melting point 310℃, glass transition temperature 100℃, heat distortion temperature HDT 105℃, purchased from Sichuan Shenghong in China

[0081] PA66 resin: EPR27, viscosity 2.7, medium viscosity, melting point 260℃, glass transition temperature 65℃, heat distortion temperature HDT 70℃, purchased from Shenma Group in China

[0082] Chopped fiber: ECS 301HP-3-H, monofilament diameter 10μm, length 3mm, purchased from Chongqing International in China

[0083] Antioxidant 1: 1098, hindered phenol type, purchased from Tianjin Li'anlong in China

[0084] Antioxidant 2: Revonox 608, high-temperature-resistant phosphite type, purchased from Qitai in China

[0085] Nucleating agent: P22, purchased from Brüggemann in Germany

[0086] Lubricant 1: lithium stearate, purchased from Foscam Chemicals

[0087] Lubricant 2: P130, available from Brueggemann, Germany

[0088] Dispersant: HBP-160, available from Wuhan Super Branching, China

[0089] Black masterbatch: 2718, PE carrier, available from Cabot, USA

[0090] S2: Test setup

[0091] Table 1 is the raw material and additive selection for experimental groups 1-4 and control groups 1-3

[0092] Raw materials Experiment group 1 Experiment group 2 Experiment group 3 Experiment group 4 Control group 1 Control group 2 Control group 3 SH406 77.8 67.8 67.5 67.3 0 0 0 SH401 0 0 0 0 0 0 67.3 EPR27 0 0 0 0 67.8 67.3 0 1098 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Revonox 608 0.2 0.2 0.2 0.2 0.2 0.2 0.2 P22 0 0 0.2 0.2 0 0.2 0.2 Lithium stearate 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P130 0.7 0.7 0.7 0.7 0.7 0.7 0.7 HBP-160 0 0 0.3 0.5 0 0.3 0.5 ECS 301 HP-3-H 20 30 30 30 30 30 30 2718 1 1 1 1 1 1 1

[0093] Example 3

[0094] The product prepared in Example 2 was tested to determine its performance in various aspects.

[0095] (I) Set up test scheme

[0096] S1: Mechanical property test

[0097] S1-1: Tensile strength test

[0098] Equipment: Instron 5967 universal material testing machine

[0099] Reference standard: ISO 527-2

[0100] Conditions: Room temperature 23±2℃, humidity 50±5% RH

[0101] Operation: Sample size 170mm*10mm*4mm, pre-load 1N, rate 10mm / min

[0102] Data processing: 5 samples were tested for each group, the average value was taken, and the standard deviation was ≤5%.

[0103] S1-2: Bending test

[0104] Reference standard: ISO 178

[0105] Support span: 64mm, indenter diameter 10mm

[0106] Sample size 80mm*10mm*4mm, rate 2mm / min, record maximum load and deflection.

[0107] S1-3: Izod notched impact strength

[0108] Reference standard: ISO 180

[0109] Test conditions: 23℃

[0110] Spline size 80mm*10mm*4mm, A type notch, record the energy value before and after the pendulum impact, 5 for each group of tests, and take the average value.

[0111] S2: Thermal performance test

[0112] S2-1: Heat deflection temperature (HDT) test

[0113] Equipment: HDT / Vicat tester

[0114] Reference standard: ISO 75-2

[0115] Ramp rate: 2℃ / min uniform heating

[0116] Load: 1.82MPa, the span of the spline is 64mm when placed

[0117] Judgment standard: the temperature when the midpoint deflection of the sample is 0.21mm.

[0118] S2-2: Melt index (MFR) test

[0119] Equipment: Melt index tester

[0120] Reference standard: ISO 1133

[0121] Conditions: 330℃, load 2.16kg, pre-pressing time 5min

[0122] Test: Cut the extrudate flowing within 10s, take 5 segments of extrudate along the time axis, and take the average value.

[0123] S3: Oil resistance test

[0124] Reference standard: ISO 175

[0125] Medium: 150℃ engine oil SAE 5W-40 soaked for 1000h

[0126] Test: The tensile strength retention rate before and after soaking is ≥85% for qualified.

[0127] S4: Solder resistance test

[0128] (i) Standard test:

[0129] Reference standard: IEC 60749-20:2020

[0130] Conditions: 10s of immersion in 260℃ soldering liquid, repeated 3 times

[0131] Evaluation: No bubbles and cracking on the surface, and the heat deflection temperature decreased by ≤5% for qualified.

[0132] (ii) Application test:

[0133] Test procedure: The board connector product needs to be surface mounted SMT, at this time the tin solder is welded on the product, which needs to withstand high temperature above 220℃, instantaneous high temperature above 265℃, and the welding processing time lasts for 20-45s.

[0134] Evaluation: It is qualified by no blistering, melting or any changes on the surface after mounting.

[0135] S5: Moisture absorption test

[0136] Reference standard: ISO 62:2008

[0137] Conditions: 23℃, 90% RH environment for 500h

[0138] Index: Water absorption rate ≤0.8%, dimensional change rate ≤0.2% are qualified.

[0139] (II) Comparison test data results

[0140] Table 2 is the average value of part of the performance test data of the experimental groups 1-4 and the control groups 1-3 Figure 2 )

[0141]

[0142] Other experimental results:

[0143] Oil resistance: After soaking in 150℃ engine oil for 1000h, the tensile strength retention rates of the experimental groups 1-4 are 88%, 87%, 88% and 89% respectively, and those of the control groups 1-3 are 75%, 78% and 85%.

[0144] Solder resistance: After 3 times of immersion in 260℃ soldering liquid, the surface of the experimental group products has no blistering, and the heat distortion temperature decreases by ≤3%; the decrease of the control group 1 is 8%, that of the control group 2 is 5%, and that of the control group 3 is 3%.

[0145] Moisture absorption: After being placed in 23℃, 90% RH environment for 500h, the water absorption rate of the experimental groups 1-4 is 0.7%-0.8%, which is significantly lower than that of the control groups 1.2%-1.5%; the dimensional change rate (length / width direction) of the experimental groups after moisture absorption is ≤0.2%, which is much lower than that of the control groups 0.5%-0.8%; the retention rate of the tensile strength and the bending modulus of the experimental groups after moisture absorption is ≥90%, while the performance decay of the control groups due to moisture absorption is 15%-20%.

[0146] (III) Results summary

[0147] S1: Relationship between test items and final products

[0148] Tensile strength, bending strength, bending modulus: mainly mechanical properties, embodying high rigidity;

[0149] Heat distortion temperature: mainly embodying heat resistance;

[0150] Melt index: mainly embodying processing fluidity, easy processability, and ability to form high-precision, thin-walled, long-flow complex parts;

[0151] Part appearance: mainly product appearance, with high gloss, low warpage, and no floating fibers, obtained by optimal formula design.

[0152] S2: summarize the information in the chart:

[0153] (1) After excessive addition of PA5T / 56 resin, the mechanical properties of the product decreased significantly;

[0154] (2) The tensile strength of experimental groups 2-4 (191.1-195.2 MPa) was significantly higher than that of control groups 1 (162.3 MPa), 2 (159.4 MPa), and 3 (185 MPa), with the highest improvement of 22.5%;

[0155] (3) The bending strength of experimental groups 2-4 (286.8-289.2 MPa) was much higher than that of the control groups (180-241 MPa), with an improvement of not less than 19.4%, indicating that the material of the present application is better in resisting bending deformation;

[0156] (4) The bending modulus of experimental groups 2-4 (112.86-113.51 x 100 MPa) was significantly higher than that of the control groups (83.13-110.49 x 100 MPa), with the highest improvement of 36.5%, proving that it is more rigid and suitable for high-precision structural parts;

[0157] (5) The notched impact strength of control group 1 (21.2 kJ / m 2 ) and control group 2 (20.5 kJ / m 2 ) was slightly higher than that of the experimental groups (13.8-15.2 kJ / m 2 ), but the impact strength of the experimental groups still met the engineering application requirements, and the comprehensive strength and rigidity advantages were more prominent;

[0158] (6) The HDT of the experimental groups (266-279℃) was much higher than that of control group 1 (229℃) and control group 2 (225℃), with an improvement of 16.2%-24.1%, fully meeting the needs of high-temperature environments (such as 150℃ long-term use and 260℃ soldering treatment) in high-end fields;

[0159] (7) The melt index of the experimental group (44-48.5 g / 10 min) is higher than that of the control group (28-37 g / 10 min), indicating that it has better processing fluidity and is suitable for injection molding of complex structures; the appearance of the product gradually improves with the increasing number of the experimental group: the experimental group 4 achieves "surface gloss without floating fibers", which is better than the "slight floating fibers" of the control group, proving that the problem of glass fiber exposure has been effectively solved and the appearance quality of the product has been improved by optimizing the dispersant (such as HBP-160) and process parameters.

[0160] S3: Result analysis

[0161] The heat distortion temperature of pure PA5T / 56 resin is not high enough to meet the requirements of high-end products, and can only reach the effect of heat distortion temperature HDT > 260°C after glass fiber modification and reinforcement, so it needs to be modified. After reinforcement with 30%-35% glass fiber, the heat resistance is greatly improved, the heat distortion temperature and rigidity are greatly improved, the bending modulus is > 9000 MPa, the dimensional stability is increased, and the water absorption is reduced.

[0162] PA5T / 56 and PA6T / 66 have basically the same performance, both belong to semi-aromatic copolymer products, can withstand 260°C SMT and long-term high-temperature 150°C conditions, and have very high rigidity. The main difference is:

[0163] (1) 6T / 66 is a petroleum-based monomer, and 5T / 56 is a semi-bio-based monomer.

[0164] (2) The structure of 6T / 66 is more symmetrical, and its melting point and upper limit of processing are relatively close under the same polymerization ratio, making it difficult to control the processability. Materials that are easy to process often need more aliphatic proportion, which reduces rigidity and heat resistance.

[0165] The addition of glass fiber changes the overall material from being carried by the matrix to being carried by the glass fiber when subjected to external force, resulting in higher impact strength. The performance is that the external force destroys the interfacial bonding between the glass fiber and the matrix and pulls out the glass fiber, which requires more energy. Therefore, the uniform dispersion of glass fiber in the matrix and the appropriate retention length of glass fiber will affect the strength and surface appearance. By accurately selecting the formula ratio and material combination, the optimal dispersion state and glass fiber length are designed, and the excellent processing fluidity is combined with the high rigidity and high heat resistance of the resin matrix to further improve the material performance.

[0166] Example 4

[0167] The PA5T / 56 resin used in Example 2 and Example 3 is commercially available SH406, so in this example, a group of resins with different 5T and 56 ratios are prepared according to the steps in Example 1, and tested to verify the relationship between the ratio and HDT.

[0168] Test materials:

[0169] Synthetic PA5T / 56 resin 5 groups, respectively, experimental groups 5-9, in which the proportion of 5T and 56 is 0.5:0.5, 0.6:0.4, 0.7:0.3, 0.8:0.2, 0.9:0.1, respectively, relative viscosity 2.4, amount 65 parts by mass; control group 4 PA66 resin, amount 65 parts by mass.

[0170] Glass fiber: alkali-free chopped glass fiber 301HP, diameter 10 μm, length 3 mm, amount 30 parts by mass.

[0171] Antioxidant: 1098+608, mass ratio 1:1, amount 0.8 parts by mass.

[0172] Nucleating agent: P22, amount 0.2 parts by mass.

[0173] Lubricant: lithium stearate, amount 0.3 parts by mass.

[0174] Dispersant: HBP-160, amount 0.5 parts by mass.

[0175] Black masterbatch: 2718, amount 1.2 parts by mass.

[0176] Test process:

[0177] According to the thermal performance test in Example 3 (heat distortion temperature HDT test).

[0178] Test results: Table 3

[0179] Table 3 is the experimental result data table of the thermal performance test

[0180]

[0181]

[0182] The HDT curve is shown in Figure 3 , and it can be found from the data and the accompanying drawings that: the HDT increases linearly with the increase of the proportion of 5T, which meets the expectation, verifying the technical logic that "the proportion of 5T increases → the heat resistance increases"; the difference between the experimental group and the control group is obvious, highlighting the material improvement effect of this scheme. In addition, we can find that after the proportion of 5T reaches 0.7, that is, 0.7:0.3→0.8:0.2→0.9:0.1, the trend of heat resistance enhancement has slowed down, at the same time, after the proportion of 5T reaches 0.7, the processing difficulty has obviously increased, which makes the practical value of the subsequent proportion has been greatly reduced.

[0183] 5T aromatic benzene ring structure in the chain increases the rigidity of the molecule, limits the chain segment movement at high temperature, so the higher the proportion, the stronger the material's ability to resist thermal deformation. Therefore, if you need to meet the 260℃ soldering scenario (such as electronic connectors), you can choose 5T / 56≥0.5:0.5 (HDT≥266℃); If used for long-term engine compartment components above 150℃, it is recommended that 5T / 56≥0.6:0.4 (HDT≥270℃) to ensure a safety margin.

[0184] In summary, the product glass fiber reinforced PA5T / 56 material prepared by the process of the application has outstanding advantages in the following aspects:

[0185] Bio-based: The source of pentanediamine is bio-based organic carbon, renewable and environmentally friendly;

[0186] High heat resistance: high strength and rigidity in a wide temperature range;

[0187] Low moisture absorption: maintains stable performance and is not affected by moisture;

[0188] Excellent chemical resistance: strong resistance to a wide range of chemicals;

[0189] Good electrical properties: suitable for electronic and electrical applications, and electrical properties do not decay in high temperature and high humidity environments;

[0190] Fast crystallization rate and high flowability: helps to shorten the production cycle and improve molding efficiency, excellent flowability, suitable for thin-walled high-precision electronic components;

[0191] Dimensional stability: maintains accurate dimensions even in complex part processing, suitable for small, integrated, high-density, high-precision high-end electronic and electrical characteristics;

[0192] High rigidity and high strength: combined with glass fiber reinforced materials, improves the overall performance of the material;

[0193] SMT compatibility: outstanding reflow soldering ability, suitable for electronic component manufacturing;

[0194] Low thermal expansion coefficient: helps to reduce dimensional changes caused by thermal expansion and contraction.

Claims

1. A glass fiber reinforced high temperature resistant bio-based nylon 5T / 56 composite material, characterized by: The invention is prepared from the following raw materials in percentage by weight: 50%-80% of PA5T / 56 resin, 20%-40% of glass fiber, 0.1%-1% of antioxidant, 0.1%-0.5% of nucleating agent, 0.1%-1% of lubricant, 0.1%-1% of dispersant and 1%-2% of black masterbatch.

2. The composite material according to claim 1, characterized in that: The PA5T / 56 resin is a copolymer of pentamethylenediamine terephthalic acid and pentamethylenediamine adipate, the ratio of 5T to 56 is (0.5-0.9): (0.1-0.5), and the relative viscosity is 2.0-2.

6.

3. The composite material according to claim 1, characterized in that: The glass fiber is an alkali-free chopped glass fiber with a single filament diameter of 8-15 μm and a chopped length of 3-6 mm, and the surface of the glass fiber is treated with a silane coupling agent.

4. The composite material according to claim 2, characterized in that: The glass fiber is a mixture of one or more of Chongqing International 301HP, Taishan Fiberglass T435TM, and Jushi Fiberglass 568H.

5. The composite material according to claim 1, characterized in that: The antioxidant is a mixture of one or more of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine, tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, bis(2,4-dicumylphenyl)pentaerythritol-diphosphite, and tris(2,4-di-tert-butylphenyl) phosphite.

6. The composite material according to claim 1, characterized in that: The nucleating agent is a mixture of one or more of P22, CAV102, ultrafine talc powder, and organic montmorillonite.

7. The composite material according to claim 1, characterized in that: The lubricant is a mixture of one or more of calcium stearate, lithium stearate, pentaerythritol stearate, oxidized polyethylene wax, partially saponified ester wax, montan acid wax, N,N'-ethylene bisstearamide, and silicone masterbatch.

8. The composite material according to claim 1, characterized in that: The dispersant is a mixture of one or more of hyperbranched polyester, hyperbranched high temperature resistant dispersant, N,N'-ethylene bisstearamide modified graft, and dendritic branched resin. Preferably, the dispersant is a mixture of HBP-160, CYD-816A, and TAF-A.

9. A method for preparing the glass fiber reinforced high temperature resistant bio-based nylon 5T / 56 composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Dry PA5T / 56 resin at 110°C for 3 h; (2) Weigh the raw materials except glass fiber and mix them at low speed for 3-5 minutes; (3) Add the mixed raw materials into the main feeding bin of the extruder, add the glass fiber from the side feeding bin, melt and mix and extrude, the temperature of each temperature zone of the extruder is: 260℃ for the first section, 330℃ for the second section, 330℃ for the third section, 320℃ for the fourth section, 320℃ for the fifth section, 310℃ for the sixth section, 300℃ for the seventh section, 300℃ for the eighth section, 310℃ for the ninth section, and 320℃ for the die head, the screw speed is 380-400r / min, and the vacuum degree is <-0.08MPa; (4) After the molten material is extruded into strips through the die of the extruder, the strips are passed through a water tank for a length of 20 cm. After absorbing the moisture on the surface of the strips, the material is cut to obtain the product composite material particles. The product is a cylindrical particle with a neat cross section; Among them, the glass fiber is added from the side feeding silo of the fourth stage of the extruder.

10. Use of the glass fiber reinforced high temperature resistant bio-based nylon 5T / 56 composite material according to any one of claims 1 to 8 or the product prepared by the preparation method according to claim 9 in electronic and electrical connectors and automobile engine parts.

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