Polyamide composition as well as preparation method and application thereof

Abstract

The invention provides a polyamide composition as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The polyamide composition is prepared from the following components in parts by weight: 30 to 70 parts of semi-aromatic polyamide, 16 to 20 parts of flame retardant, 15 to 50 parts of reinforcing filler, 0.5 to 2 parts of copolymer containing glycidyl methacrylate and 0.5 to 1 part of amino silicon dioxide microspheres, the relative viscosity of the semi-aromatic polyamide is 1.7 to 2.4. According to the semi-aromatic polyamide composition, the copolymer containing glycidyl methacrylate and the amino silicon dioxide microspheres are added into the semi-aromatic polyamide with specific relative viscosity, and the foaming resistance of the polyamide composition is improved through the synergistic effect.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a polyamide composition, a preparation method thereof and an application thereof. Background Art

[0002] At present, due to the popularization of new energy vehicle domain controllers, new energy vehicles undertake a series of functions such as audio-visual entertainment and intelligent driving, and the entire data transmission volume is continuously increasing. In this case, traditional wire harness connections can no longer meet the overall needs, and the increasing number of connectors makes integration and encapsulation an inevitable trend. Therefore, the number of automotive SMT connectors is continuously increasing.

[0003] Different from common consumer electronics SMT, the sizes and shapes of connectors on automotive PCB boards vary greatly. In order to ensure that large and small components have the same thermal expansion and avoid the phenomenon of non-welding such as void soldering, a welding method of first preheating the whole and then rapidly heating up is required. Compared with the gradually heating welding method of common consumer electronics, the welding method of first preheating the whole and then rapidly heating up makes the moisture in the product unable to volatilize, but rapidly volatilizes near 260°C when the temperature reaches the reflow soldering temperature, causing problems such as bulging and blistering of the material, which not only affects the appearance of the product, but also greatly affects the safety of the product.

[0004] Previously, the flame retardant grade of automotive connectors was mostly HB specification, so the overall tolerance to SMT was good. However, in recent years, due to the need to improve safety, the overall flame retardant grade of automotive connectors has been transformed to V-0 specification. At the same time, due to environmental protection regulations and other reasons, halogen-free flame retardant materials are preferred. Since the processing temperature of high-temperature nylon is relatively high, aluminum diethylphosphinate is used for all halogen-free flame retardant high-temperature nylons. This flame retardant has strong acidity, and at high temperatures, its decomposition products will promote the decomposition of nylon materials, resulting in more small molecules, increasing the risk of blistering of the material under SMT. Currently, the blister resistance of halogen-free flame retardant high-temperature nylon materials is generally 10 degrees lower than the blistering temperature of non-flame retardant HB specification, causing frequent blistering problems in current automotive connector SMT. Summary of the Invention

[0005] The purpose of the present disclosure is to overcome the deficiencies of the prior art, and provides a polyamide composition, a preparation method thereof and an application thereof.

[0006] To achieve the above purpose, the technical solution adopted by the present disclosure is: In the first aspect, a polyamide composition is provided, which includes the following components in parts by weight: 30-70 parts of semi-aromatic polyamide, 16-20 parts of flame retardant, 15-50 parts of reinforcing filler, 0.5-2 parts of a copolymer containing glycidyl methacrylate, 0.5-1 part of amino silica microspheres; the relative viscosity of the semi-aromatic polyamide is 1.7-2.4.

[0007] In some embodiments, the glycidyl methacrylate-containing copolymer is at least one of ethylene-glycidyl methacrylate copolymer, ethylene-butyl acrylate-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate copolymer, and glycidyl methacrylate-grafted polyolefin elastomer.

[0008] In some embodiments, the content of glycidyl methacrylate in the glycidyl methacrylate-containing copolymer is 3-8 wt%.

[0009] In some embodiments, the weight portion of the glycidyl methacrylate-containing copolymer is 0.8-1.3 parts.

[0010] In some embodiments, the semi-aromatic polyamide is at least one of PA6T / 66, PA6I / 66, PA6T / 6I, PA9T, PA10T, PA12T, and PA12I.

[0011] In some embodiments, the flame retardant is aluminum diethyl phosphinate.

[0012] In some embodiments, the reinforcing filler is at least one of carbon fiber, glass fiber, potassium titanate fiber, glass bead, and glass flake.

[0013] In some embodiments, the polyamide composition further comprises 0.1-3 parts by weight of a processing aid; the processing aid is at least one of an antioxidant and a lubricant.

[0014] Second, a method for preparing the polyamide composition is provided, comprising the following steps:

[0015] Mix each component evenly to obtain a premix, and the premix does not include the reinforcing filler and the flame retardant;

[0016] Add the premix to the main feed port of a screw extruder, add the reinforcing filler to the first side feed port of the screw extruder, add the flame retardant to the second side feed port of the screw extruder, and melt extrude and pelletize to obtain the polyamide composition.

[0017] Third, the application of the polyamide composition in preparing a surface mount device is provided.

[0018] Fourth, a surface mount component is provided, and the surface mount component contains the polyamide composition.

[0019] Fifth, an automotive SMT connector is provided, and the automotive SMT connector contains the polyamide composition.

[0020] Compared with the prior art, the beneficial effects of the present disclosure are as follows: By adding a copolymer containing glycidyl methacrylate and amino silica microspheres to a semi-aromatic polyamide with a specific relative viscosity, the present invention synergistically improves the anti-foaming property of the polyamide composition; the epoxy structure in the copolymer containing glycidyl methacrylate and the semi-aromatic polyamide form a slight cross-linked structure at high temperature, which improves the heat distortion temperature of the polyamide composition. Under the condition of the same water absorption rate, increasing the heat distortion temperature of the polyamide composition can reduce the lubrication degree on the surface of the polyamide composition, so that water will not damage the surface of the polyamide composition during volatilization, avoiding phenomena such as bulging and foaming. On the one hand, the alkalinity of the amino silica microspheres can effectively absorb the acidic small molecules generated by the decomposition of the flame retardant at high temperature, effectively inhibiting the damage of the acidic small molecules to the polyamide composition; on the other hand, the amino groups in the amino silica microspheres and the epoxy structure in the copolymer containing glycidyl methacrylate serve as cross-linking points of the cross-linked structure, effectively improving the heat distortion temperature of the polyamide composition, making the polyamide composition have high hardness at high temperature and not easily foaming due to water volatilization. The common action improves the anti-foaming property of the polyamide composition, so that the polyamide composition with a flame retardant grade of V-0 and the polyamide composition with a flame retardant grade of HB have similar anti-foaming temperatures. Description of the Drawings

[0021] Figure 1 It is a graph showing the anti-foaming property test of the polyamide compositions of Example 2, Comparative Example 2 and Comparative Example 9 at a temperature of T1. Detailed Embodiments

[0022] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure content of the present disclosure more thorough and comprehensive.

[0023] As used herein, the terms:

[0024] "Prepared from..." is synonymous with "comprising". As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or device containing the listed elements is not necessarily limited to those elements, but may include other elements not explicitly listed or elements inherent to such composition, step, method, article or device.

[0025] The connective "consisting of" excludes any unrecited element, step, or component. If used in a claim, this phrase renders the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause within the body of a claim rather than immediately following the subject, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0026] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, whether or not that range is separately disclosed. For example, when the range "1 - 5" is disclosed, the described range should be interpreted to include ranges "1 - 4", "1 - 3", "1 - 2", "1 - 2 and 4 - 5", "1 - 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within that range.

[0027] In these examples, unless otherwise specified, the parts and percentages are by mass.

[0028] "Parts by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g or 2.689 g, etc. If we say that the mass parts of component A is a parts and the mass parts of component B is b parts, it means the mass ratio of component A to component B is a:b. Or, it means the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from the number of mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0029] "And / or" is used to indicate that either or both of the stated circumstances may occur. For example, A and / or B includes (A and B) and (A or B).

[0030] To solve the problem of poor anti - foaming property of semi - aromatic polyamide materials in the prior art.

[0031] In a first aspect, the present invention provides a polyamide composition, comprising the following components in parts by weight: 30 - 70 parts of semi - aromatic polyamide, 16 - 20 parts of flame retardant, 15 - 50 parts of reinforcing filler, 0.5 - 2 parts of a copolymer containing glycidyl methacrylate, 0.5 - 1 part of amino silica microspheres;

[0032] The relative viscosity of the semi - aromatic polyamide is 1.7 - 2.4.

[0033] In different embodiments, the weight parts of the semi-aromatic polyamide can be, but are not limited to, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts;

[0034] In different embodiments, the weight parts of the flame retardant can be, but are not limited to, 16 parts, 16.5 parts, 17 parts, 17.5 parts, 18 parts, 18.5 parts, 19 parts, 19.5 parts, 20 parts;

[0035] In different embodiments, the weight parts of the reinforcing filler can be, but are not limited to, 15 parts, 17 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 48 parts, 50 parts;

[0036] In different embodiments, the weight parts of the copolymer containing glycidyl methacrylate can be, but are not limited to, 0.5 parts, 0.7 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2.0 parts, and preferably 0.8 - 1.3 parts.

[0037] In different embodiments, the weight parts of the amino silica microspheres can be, but are not limited to, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 parts.

[0038] In different embodiments, the relative viscosity of the semi-aromatic polyamide can be, but is not limited to, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4. The test method refers to GB12006.1-89, the method for determining the viscosity number of polyamide; the specific test method is: measure the relative viscosity ηr of the polyamide with a concentration of 0.25 g / dl in 98% concentrated sulfuric acid at 25 ± 0.01 °C.

[0039] In the present invention, by adding a copolymer containing glycidyl methacrylate and amino silica microspheres to a semi-aromatic polyamide with a specific relative viscosity, the foaming resistance of the polyamide composition is improved through their synergistic effect; the epoxy structure in the copolymer containing glycidyl methacrylate and the semi-aromatic polyamide form a slight cross-linked structure at high temperature, increasing the heat distortion temperature of the polyamide composition. Under the condition of the same water absorption rate, increasing the heat distortion temperature of the polyamide composition can reduce the lubrication degree on the surface of the polyamide composition, so that water will not damage the surface of the polyamide composition during volatilization, avoiding phenomena such as bulging and foaming. On the one hand, the basicity of the amino silica microspheres can effectively absorb the acidic small molecules generated by the decomposition of the flame retardant at high temperature, effectively inhibiting the damage of the acidic small molecules to the polyamide composition; on the other hand, the amino groups in the amino silica microspheres and the epoxy structure in the copolymer containing glycidyl methacrylate serve as cross-linking points of the cross-linked structure, effectively increasing the heat distortion temperature of the polyamide composition, making the polyamide composition have high hardness at high temperature and not easily foaming due to water volatilization. Their common action improves the foaming resistance of the polyamide composition, making the polyamide compositions with a flame retardant grade of V-0 and a flame retardant grade of HB have similar foaming resistance temperatures.

[0040] The relative viscosity of the semi-aromatic polyamide is one of the factors affecting the foaming resistance of the polyamide composition. If the relative viscosity of the semi-aromatic polyamide is too low, the molecular weight of the semi-aromatic polyamide is small and it is easily decomposed at high temperature, easily leading to foaming of the polyamide composition; if the relative viscosity of the semi-aromatic polyamide is too high, during the processing process, the shear strength required for the semi-aromatic polyamide is high, easily causing strong decomposition of the flame retardant, making the polyamide composition more likely to have foaming problems.

[0041] Specifically, the relative viscosity of the polyamide composition is 2 - 3, for example, it can be but not limited to 2, 2.2, 2.4, 2.6, 2.8, 3.

[0042] In addition, the weight part of the copolymer containing glycidyl methacrylate is also one of the factors affecting the foaming resistance of the polyamide composition. When the weight part of the copolymer containing glycidyl methacrylate is 0.8 - 1.3 parts, the obtained polyamide composition has better foaming resistance.

[0043] Specifically, in the polyamide composition, the mass percentage content of the semi-aromatic polyamide is not less than 30%.

[0044] Specifically, in the present invention, the amino silica microspheres refer to silica microspheres surface-modified with amino groups.

[0045] Specifically, the diameter of the amino silica microspheres is 10 nm - 10 μm.

[0046] In some embodiments, the glycidyl methacrylate-containing copolymer is at least one of ethylene-glycidyl methacrylate copolymer, ethylene-butyl acrylate-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate copolymer, and glycidyl methacrylate-grafted polyolefin elastomer.

[0047] In the present invention, the glycidyl methacrylate-containing copolymer can be at least one of a binary copolymer and a terpolymer, and is preferably a terpolymer.

[0048] In some embodiments, the content of glycidyl methacrylate in the glycidyl methacrylate-containing copolymer is 3-8 wt%, for example, it can be but not limited to 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, and its test method is the JNC method.

[0049] In the present invention, the glycidyl methacrylate-containing copolymer with the content of glycidyl methacrylate within the above range can further improve the foam resistance of the polyamide composition.

[0050] In some embodiments, the semi-aromatic polyamide is at least one of PA6T / 66, PA6I / 66, PA6T / 6I, PA9T, PA10T, PA12T, and PA12I.

[0051] In some embodiments, the flame retardant is aluminum diethylphosphinate.

[0052] In some embodiments, the reinforcing filler is at least one of carbon fiber, glass fiber, potassium titanate fiber, glass bead, and glass flake.

[0053] In some embodiments, the polyamide composition further comprises 0.1-3 parts by weight of an auxiliary agent, and the auxiliary agent is at least one of an antioxidant and a lubricant.

[0054] Specifically, the antioxidant is at least one of phenolic antioxidants, phosphite antioxidants, divalent sulfur antioxidants or hindered amine antioxidants. Among them, the phenolic antioxidant can be selected from at least one of antioxidant 264, antioxidant 1010, antioxidant 1076, antioxidant SP, antioxidant 2246, antioxidant CA, antioxidant 330, Irganox1098 and antioxidant 3114; the phosphite antioxidant can be selected from at least one of antioxidant TNP, antioxidant ODP, antioxidant 168, Irganox1093 and Irganox1222; the divalent sulfur antioxidant can be selected from at least one of dilauryl thiodipropionate (DLTP) and distearyl thiodipropionate (DSTP); the hindered amine antioxidant can be selected from at least one of LS-744, LS-770, GW-540 and Flamstab NOR116.

[0055] Specifically, the lubricant is at least one of low molecular weight lipid lubricants, metal soap lubricants, stearic acid composite ester lubricants, and amide lubricants. Among them, the low molecular weight lipid lubricant can be selected from at least one of solid paraffin, liquid paraffin and low molecular weight polyolefin wax; the metal soap lubricant can be selected from at least one of calcium stearate, magnesium stearate, zinc stearate and barium stearate; the stearic acid composite ester lubricant can be selected from at least one of ethylene glycol stearate, glycerol stearate and pentaerythritol stearate; the amide lubricant can be selected from at least one of erucamide, methylene bis stearamide and N,N-ethylene bis stearamide.

[0056] There is no special limitation on the production method of the polyamide composition of the present invention, and it is carried out using a blending device such as a mixer, a single-screw or twin-screw extruder. There is no particularly strict limitation on the addition order of the components. They can be added simultaneously or in a certain order. Two or more components can be selected from all components for pre-mixing or kneading. For example, a copolymer containing glycidyl methacrylate, amino silica microspheres and semi-aromatic polyamide can be pre-formed into a polyamide masterbatch, and then added to the melt of other components in the form of the masterbatch according to a set ratio for extrusion. Under the condition that the mixing ability of the equipment permits, when molding or producing parts, the masterbatch and the particles formed by other components can also be mixed and melt-processed according to a set ratio.

[0057] Specifically, the preparation method of the polyamide composition of the present invention includes the following steps:

[0058] Mix each component evenly to obtain a premix, and the premix does not include reinforcing fillers and flame retardants;

[0059] Add the premix to the main feeding port of a screw extruder, add the reinforcing filler to the first side feeding port of the screw extruder, add the flame retardant to the second side feeding port of the screw extruder, and perform melt extrusion granulation to obtain a polyamide composition.

[0060] Specifically, the temperature for the melt extrusion granulation is 290 - 330 °C, for example, it can be but is not limited to 290 °C, 300 °C, 310 °C, 320 °C, 330 °C.

[0061] In a third aspect, there is provided an application of the described polyamide composition in the preparation of surface mount devices; such as automotive BMS connectors, domain control connectors, DDR5, mobile phone TYPE-C, wafers, pin headers, battery holders, etc.

[0062] In a fourth aspect, there is provided a surface mount component, and the surface mount component contains the described polyamide composition.

[0063] In a fifth aspect, there is provided an automotive SMT connector, and the automotive SMT connector contains the described polyamide composition.

[0064] The raw materials used in the examples and comparative examples are described as follows, but are not limited to these materials:

[0065] Semi-aromatic polyamide:

[0066] PA10T-1: Relative viscosity is 1.7, PPA-1, Kingfa;

[0067] PA10T-2: Relative viscosity is 2.4, PPA-2, Kingfa;

[0068] PA10T-3: Relative viscosity is 1.5, PPA-3, Kingfa;

[0069] PA10T-4: Relative viscosity is 2.7, PPA-4, Kingfa;

[0070] Flame retardant: Aluminum diethylphosphinate, Clariant;

[0071] Reinforcing filler: 3 mm chopped glass fiber, ECS301HP, Chongqing International Composite Materials Co., Ltd.;

[0072] Copolymer-1 containing glycidyl methacrylate: Ethylene-methyl acrylate-glycidyl methacrylate copolymer, the content of glycidyl methacrylate is 3 wt%, BF-7L, Sumitomo Chemical;

[0073] Glycidyl methacrylate-containing copolymer-2: ethylene-methyl acrylate-glycidyl methacrylate copolymer, with a glycidyl methacrylate content of 6 wt%, BF-7M, Sumitomo Chemical;

[0074] Glycidyl methacrylate-containing copolymer-3: ethylene-methyl acrylate-glycidyl methacrylate copolymer, with a glycidyl methacrylate content of 8 wt%, AX8900, Arkema France;

[0075] Glycidyl methacrylate-containing copolymer-4: ethylene-glycidyl methacrylate copolymer, with a glycidyl methacrylate content of 6 wt%, BF-2C, Sumitomo Chemical;

[0076] Glycidyl methacrylate: commercially available;

[0077] Amino silica microspheres: with an average particle size of 100 nm, Zhongke Keyou;

[0078] Silica microspheres: with an average particle size of 100 nm, Zhongke Keyou;

[0079] Calcium oxide: with an average particle size of 100 nm, commercially available.

[0080] Examples and comparative examples

[0081] The compositions and parts by weight of the polyamide compositions in the examples and comparative examples are shown in Tables 1 and 2.

[0082] The preparation methods of the polyamide compositions in the examples and comparative examples include the following steps:

[0083] According to the parts by weight in Tables 1 and 2, the glycidyl methacrylate-containing copolymer, amino silica microspheres, and semi-aromatic polyamide are mixed evenly to obtain a premix;

[0084] The premix is added to the main feed port of a twin-screw extruder, the reinforcing filler is added to the first side feed port of the screw extruder, and the flame retardant is added to the second side feed port of the screw extruder, and melt extrusion granulation is carried out to obtain a polyamide composition; the temperature of the melt extrusion granulation is 290 - 340 °C, the length-diameter ratio of the screw of the twin-screw extruder is 52:1, and the screw speed is 200 rpm.

[0085] Table 1

[0086]

[0087]

[0088] Table 2

[0089]

[0090] Performance test

[0091] The polyamide compositions obtained in the examples and comparative examples were subjected to performance tests, and the test methods are as follows:

[0092] (1) Moisture content: Referring to ISO62 for testing, the polyamide composition was injection molded into a square plate with dimensions of 60mm * 60mm * 1mm, and the initial weight was recorded. Then, it was left standing for 168h at 85°C / 85% humidity, and the weight after standing was recorded. The moisture content = (weight after standing - initial weight) / initial weight.

[0093] (2) Foaming resistance: The polyamide composition was injection molded into a square plate with dimensions of 60mm * 60mm * 1mm, and the initial weight was recorded. Then, it was left standing for 168h at 85°C / 85% humidity, and then surface mount soldering tests were carried out at temperatures of 240°C - 260°C - 280°C - 300°C (T1) and 250°C - 270°C - 290°C - 310°C (T2) respectively, and the foaming situation was observed (a total of 100 plates were processed, and the total number of square plates with bubbles was counted).

[0094] (3) Heat distortion temperature: Tested with reference to ISO75.

[0095] (4) Flame retardant grade: Referring to the UL94 V-0 test standard, the standard bar specimen size is 125 ± 5mm in length, 13.0 ± 0.5mm in width, and 0.8mm in thickness; 5 specimens were treated at 23 ± 2°C, 50 ± 5% for at least 48 hours. Align the Bunsen burner flame with the center of the lower end of the specimen, and keep the distance between the center of the top surface of the Bunsen burner tube and the lower end surface of the specimen at 10 ± 1mm, and maintain this distance for 10 ± 0.5S: If necessary, move the Bunsen burner as the position of the specimen length changes. After applying the flame to the specimen for 10 ± 0.5S, immediately withdraw the Bunsen burner at a speed of about 300mm / s to a position at least 150mm away from the specimen. At the same time, use a timing device to measure the flaming combustion time T1 (in units of s) of the specimen. After the flaming combustion of the specimen stops, even if the Bunsen burner has not been withdrawn from the specimen far enough by 150mm, immediately move the Bunsen burner to the lower end surface of the specimen to keep the distance at 10 ± 1mm, apply the flame again for 10 ± 0.5S, and move the Bunsen burner away if necessary to remove the dripping matter. Immediately withdraw the Bunsen burner away from the specimen at least 150mm after applying the flame, and at the same time start the timing device to measure the flaming time T2 and the non-flaming combustion time T3 of the specimen, and record T2 and T3. If T1 + T2 + T3 < 10s for all 5 specimens and there is no dripping to ignite the cotton below, it is considered to meet the V-0 condition.

[0096] The test results are shown in Table 3.

[0097] Table 3

[0098]

[0099]

[0100] As can be seen from Table 3, the water content of the polyamide composition of the present invention is 0.7 - 1.05%, the heat distortion temperature is above 290, and at the temperature (T1) of 240°C - 260°C - 280°C - 300°C, the number of blisters is 0. At the temperature (T2) of 250°C - 270°C - 290°C - 310°C, the number of blisters is 75 - 100, indicating that the polyamide composition of the present invention has high blister resistance.

[0101] Comparing Comparative Example 3, Example 4 and Comparative Examples 1 - 2, it can be seen that when the relative viscosity of the polyamide < 1.7 or > 2.4, the number of blisters of the polyamide composition at the temperature (T1) of 240°C - 260°C - 280°C - 300°C is ≥ 45, and at the temperature (T2) of 250°C - 270°C - 290°C - 310°C, all of them have bubbles, indicating that when the relative viscosity of the polyamide is not within the range of 1.7 - 2.4, the blister resistance of the obtained polyamide composition is poor.

[0102] Comparing Comparative Example 3, Examples 5 - 7, it can be seen that when the content of glycidyl methacrylate in the glycidyl methacrylate copolymer is 3 - 6 wt%, the number of blisters of the polyamide composition at the temperature (T2) of 250°C - 270°C - 290°C - 310°C is ≤ 89, indicating that when the content of glycidyl methacrylate in the glycidyl methacrylate copolymer is 3 - 6 wt%, the blister resistance of the polyamide composition is excellent.

[0103] Comparing Comparative Example 3 and Examples 8 - 11, it can be seen that when the weight part of the glycidyl methacrylate copolymer is 0.8 - 1.3, the number of blisters of the polyamide composition at the temperature (T2) of 250°C - 270°C - 290°C - 310°C is ≤ 95, indicating that when the weight part of the glycidyl methacrylate copolymer is 0.8 - 1.3, the blister resistance of the polyamide composition is better.

[0104] Comparing Comparative Example 3 and Comparative Example 3, it can be seen that when using glycidyl methacrylate to replace the glycidyl methacrylate copolymer, the number of blisters of the polyamide composition at the temperature (T1) of 240°C - 260°C - 280°C - 300°C is ≥ 45, indicating that only the copolymer containing glycidyl methacrylate can improve the blister resistance of the polyamide composition.

[0105] Comparing Comparative Example 1 with Comparative Examples 4-5, it can be seen that when other analogues are used to replace the amino silica microspheres, the number of foams of the polyamide composition is ≥66 at the temperatures (T1) of 240°C - 260°C - 280°C - 300°C, indicating that only the amino silica microspheres can improve the foam resistance of the polyamide composition.

[0106] Comparing Example 1 with Comparative Examples 6-8, it can be seen that when at least one of the glycidyl methacrylate copolymer or the amino silica microspheres is missing, the number of foams of the polyamide composition is ≥12 at the temperatures (T1) of 240°C - 260°C - 280°C - 300°C, indicating that only the combined use of the glycidyl methacrylate copolymer and the amino silica microspheres can improve the foam resistance of the polyamide composition.

[0107] Comparing Example 3 with Comparative Example 9, it can be seen that when the addition amount of the glycidyl methacrylate copolymer is too much, the number of foams of the polyamide composition is ≥32 at the temperatures (T1) of 240°C - 260°C - 280°C - 300°C.

[0108] Figure 1 It is a graph showing the foam resistance test of the polyamide compositions of Example 2, Comparative Example 2 and Comparative Example 9 at the temperature of T1. From Figure 1 it can be seen that for the polyamide composition of Example 2 at the temperature of T1, there is no foaming phenomenon; for the polyamide composition of Comparative Example 2, there are a large number of foaming phenomena and the average particle size of the bubbles is large; for the polyamide composition of Comparative Example 9, there are a small number of foaming phenomena and the average particle size of the bubbles is small.

[0109] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present disclosure rather than to limit the protection scope of the present disclosure. Although the present disclosure has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present disclosure can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present disclosure.

Claims

1. A polyamide composition, characterized in that The invention comprises the following components in parts by weight: 30-70 parts of semi-aromatic polyamide, 16-20 parts of flame retardant, 15-50 parts of reinforcing filler, 0.5-2 parts of copolymer containing glycidyl methacrylate, and 0.5-1 parts of amino silicon dioxide microspheres; the relative viscosity of the semi-aromatic polyamide is 1.7-2.

4.

2. The polyamide composition according to claim 1, characterized in that The copolymer containing glycidyl methacrylate is at least one of ethylene-glycidyl methacrylate copolymer, ethylene-butyl acrylate-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate copolymer, and glycidyl methacrylate grafted polyolefin elastomer.

3. The polyamide composition according to claim 1, characterized in that The content of glycidyl methacrylate in the glycidyl methacrylate-containing copolymer is 3-8 wt %.

4. The polyamide composition according to claim 1, characterized in that The weight portion of the copolymer containing glycidyl methacrylate is 0.8-1.3 parts.

5. The polyamide composition according to claim 1, characterized in that The semi-aromatic polyamide is at least one of PA6T / 66, PA6I / 66, PA6T / 6I, PA9T, PA10T, PA12T, and PA12I; And / or, the flame retardant is aluminum diethylphosphinate; And / or, the reinforcing filler is at least one of carbon fiber, glass fiber, potassium titanate fiber, glass microbeads, and glass flakes.

6. The polyamide composition according to claim 1, characterized in that The polyamide composition further comprises 0.1-3 parts by weight of a processing aid; the processing aid is at least one of an antioxidant and a lubricant.

7. A method for preparing a polyamide composition according to any one of claims 1 to 6, characterized in that: The following steps are involved: Mixing the components uniformly to obtain a premix, wherein the premix does not include reinforcing fillers and flame retardants; The premix is ​​added to the main feed port of the screw extruder, the reinforcing filler is added to the first side feed port of the screw extruder, the flame retardant is added to the second side feed port of the screw extruder, and the mixture is melt-extruded and granulated to obtain a polyamide composition.

8. Use of the polyamide composition according to any one of claims 1 to 6 in the preparation of surface mount devices.

9. A surface mount component, characterized in that: A polyamide composition comprising any one of claims 1 to 6.

10. An automotive SMT connector, characterized in that: A polyamide composition comprising any one of claims 1 to 6.

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