A semi-aromatic polyamide material, its preparation method and application

Abstract

This disclosure provides a semi-aromatic polyamide material, its preparation method, and its applications, belonging to the field of polymer materials technology. The semi-aromatic polyamide material of this disclosure comprises the following components in parts by weight: 45-62 parts of a first polyamide, 5-10 parts of a second polyamide, 3-5 parts of polyvinylpyrrolidone, 10-12 parts of a flame retardant, and 20-30 parts of filler. This disclosure adds a second polyamide and polyvinylpyrrolidone to the first polyamide. The polyvinylpyrrolidone disrupts the hydrogen bonds between the first and second polyamides, causing amide exchange between them. This results in the semi-aromatic polyamide material simultaneously possessing good light transmittance, weld strength, and solvent resistance. Furthermore, the high benzene ring content of the semi-aromatic polyamide allows for flame retardancy even with the addition of a small amount of flame retardant, yielding a semi-aromatic polyamide material with high flame retardancy.

Description

Technical Field

[0001] This disclosure relates to the field of polymer materials technology, specifically to a semi-aromatic polyamide material and its preparation method and application. Background Technology

[0002] Currently, due to the increased current and voltage values, new energy vehicles generate significantly more heat, placing higher demands on the thermal management and battery systems. For this reason, the thermal management system no longer uses traditional water as a cooling medium, but instead uses ethylene glycol / water solution. However, ethylene glycol places extremely high demands on the solvent resistance of materials. After 96 hours of use in heated ethylene glycol, the mechanical properties of typical PA66 material will decrease to below 50%. Simultaneously, due to processing efficiency and airtightness requirements, the materials used in the thermal management and battery systems are connected using laser welding. Laser welding requires extremely high light transmittance; some solvent-resistant materials, such as polyphenylene sulfide, have poor light transmittance, resulting in poor laser welding performance and inability to guarantee weld strength and airtightness. Furthermore, new energy vehicles are currently more sensitive to ignition and fire, requiring flame-retardant materials. The addition of flame retardants further reduces the light transmittance of the materials, compromising weldability.

[0003] Therefore, there is an urgent need for a material that is solvent-resistant, light-transmitting, flame-retardant, and has high laser welding strength. Summary of the Invention

[0004] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a semi-aromatic polyamide material that simultaneously possesses solvent resistance, light transmittance, flame retardancy, and high laser welding strength, as well as its preparation method and application.

[0005] To achieve the above objectives, the technical solution adopted in this disclosure is as follows: In the first aspect, a semi-aromatic polyamide material is provided, comprising the following components in parts by weight: 45-62 parts of first polyamide, 5-10 parts of second polyamide, 3-5 parts of polyvinylpyrrolidone, 10-12 parts of flame retardant, and 20-30 parts of filler.

[0006] In this embodiment, both the first polyamide and the second polyamide are copolymers of dicarboxylic acid and hexamethylenediamine, and the dicarboxylic acid is terephthalic acid and isophthalic acid;

[0007] Based on a total molar content of 100% for dicarboxylic acids, the first polyamide contains repeating units derived from the following: 60-70% molar content of terephthalic acid and 30-40% molar content of isophthalic acid;

[0008] The second polyamide comprises repeating units derived from the following: 30-40% terephthalic acid and 60-70% isophthalic acid.

[0009] In some embodiments, the molar content of terephthalic acid in the first polyamide is 65-70%.

[0010] In some embodiments, the second polyamide is 6.5-8 parts by weight.

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

[0012] In some embodiments, the filler is at least one of fibrous filler and non-fibrous filler; the fibrous filler is selected from at least one of glass fiber, carbon fiber, and organic fiber, and the non-fibrous filler is selected from at least one of granular filler, layered filler, and nanofiller.

[0013] In some embodiments, the semi-aromatic polyamide material further includes 1-3 parts by weight of processing aids; the processing aids include at least one of heat stabilizers, antioxidants, nucleating agents, antistatic agents, foaming agents, lubricants, plasticizers, mold release agents, and pigments.

[0014] Secondly, a method for preparing the semi-aromatic polyamide material is provided, comprising the following steps: mixing the components in proportion and then performing melt extrusion granulation to obtain the semi-aromatic polyamide material.

[0015] In some embodiments, the temperature of the melt extrusion granulation is 290-340°C.

[0016] Thirdly, the application of the aforementioned semi-aromatic polyamide material in the preparation of laser-welded parts is provided.

[0017] Fourthly, a laser-welded component is provided, the laser-welded component comprising the aforementioned semi-aromatic polyamide material.

[0018] Compared with the prior art, the beneficial effects of this disclosure are as follows: This disclosure adds a second polyamide and polyvinylpyrrolidone to the first polyamide, and the hydrogen bonds between the first polyamide and the second polyamide are broken by polyvinylpyrrolidone, so that the first polyamide and the second polyamide undergo amide exchange, so that the semi-aromatic polyamide material has good light transmittance, welding strength and solvent resistance at the same time; in addition, the semi-aromatic polyamide has a high benzene ring content, which can achieve flame retardancy with the addition of a small amount of flame retardant, and obtain a semi-aromatic polyamide material with high flame retardancy. Detailed Implementation

[0019] To facilitate understanding of this disclosure, a more complete description will be provided below. However, this disclosure may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0020] As used in this article:

[0021] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0022] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0023] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1-5” is disclosed, the described range should be interpreted as including ranges “1-4”, “1-3”, “1-2”, “1-2 and 4-5”, “1-3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0024] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0025] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0026] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0027] In a first aspect, this disclosure provides a semi-aromatic polyamide material comprising the following components in parts by weight: 45-62 parts of a first polyamide, 5-10 parts of a second polyamide, 3-5 parts of polyvinylpyrrolidone, 10-12 parts of a flame retardant, and 20-30 parts of a filler.

[0028] Among them, the first polyamide (PA6T / 6I) and the second polyamide (PA6I / 6T) are both copolymers of dicarboxylic acid and hexamethylenediamine, and the dicarboxylic acid is terephthalic acid and isophthalic acid;

[0029] Based on a total molar content of 100% for dicarboxylic acids, the first polyamide comprises repeating units derived from the following: 60-70% molar content of terephthalic acid and 30-40% molar content of isophthalic acid; the second polyamide comprises repeating units derived from the following: 30-40% molar content of terephthalic acid and 60-70% molar content of isophthalic acid.

[0030] This disclosure involves adding a second polyamide and polyvinylpyrrolidone to the first polyamide. The polyvinylpyrrolidone disrupts the hydrogen bonds between the first and second polyamides, causing amide exchange between them. This results in a semi-aromatic polyamide material that simultaneously possesses good light transmittance, weld strength, and solvent resistance. Furthermore, the high benzene ring content of the semi-aromatic polyamide allows for flame retardancy even with the addition of a small amount of flame retardant, thus obtaining a semi-aromatic polyamide material with high flame retardancy.

[0031] Specifically, the weight parts of the first polyamide can be, but are not limited to, 45 parts, 48 ​​parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, 60 parts, or 62 parts;

[0032] Specifically, the second polyamide can be in parts by weight of, but is not limited to, 5, 6, 7, 8, 9, or 10 parts; preferably 6.5-8 parts.

[0033] Specifically, the polyvinylpyrrolidone can be in parts by weight of, but is not limited to, 3 parts, 3.2 parts, 3.5 parts, 3.7 parts, 4 parts, 4.3 parts, 4.5 parts, 4.8 parts, or 5 parts;

[0034] Specifically, the flame retardant may be present in, but is not limited to, 10 parts, 10.2 parts, 10.5 parts, 10.7 parts, 11 parts, 11.3 parts, 11.8 parts, or 12 parts by weight.

[0035] Specifically, the weight parts of the filler can be, but are not limited to, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or 30 parts.

[0036] Specifically, based on the total molar content of dicarboxylic acids being 100%, the molar content of terephthalic acid in the first polyamide can be, but is not limited to, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, or 70%; preferably 65-70%; and the molar content of isophthalic acid can be, but is not limited to, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40%.

[0037] Specifically, taking the total molar content of dicarboxylic acids as 100%, the molar content of terephthalic acid in the second polyamide can be, but is not limited to, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40%; and the molar content of isophthalic acid can be, but is not limited to, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, or 70%.

[0038] Specifically, in this disclosure, the molar content of terephthalic acid and isophthalic acid in the first polyamide and the second polyamide affects the performance of the semi-aromatic polyamide material. If the molar content of terephthalic acid in the first polyamide is less than 60%, the solvent resistance of the semi-aromatic polyamide material will decrease significantly. If the molar content of terephthalic acid in the second polyamide is greater than 40%, the solvent resistance of the semi-aromatic polyamide material will decrease significantly. This disclosure preferably uses a molar content of terephthalic acid of 65-70% in the first polyamide to obtain a semi-aromatic polyamide material with high light transmittance, flame retardancy, laser welding strength and solvent resistance.

[0039] Specifically, the weight part of the second polyamide is also one of the factors affecting the performance of semi-aromatic polyamide materials. If the weight part of the second polyamide is too low, it will lead to a decrease in the light transmittance and laser welding strength of the semi-aromatic polyamide material; if the weight part of the second polyamide is too high, it will lead to a decrease in the solvent resistance of the semi-aromatic polyamide material.

[0040] Specifically, based on the mass percentage of the polyamide material being 100%, the total mass percentage of the first polyamide and the second polyamide is not less than 35%; preferably, the total mass percentage of the first polyamide and the second polyamide is not less than 40%, and more preferably, the total mass percentage of the first polyamide and the second polyamide is not less than 45%.

[0041] Specifically, the first and second polyamides can be capped using an end-capping agent. This end-capping agent reacts with the chain ends of the growing segments during the polymerization of the first or second polyamide, achieving the purpose of controlling the molecular weight of the first or second polyamide or changing the type or activity of the end groups. The end-capping agent is selected from carboxylic acids containing only one reactive carboxyl group. The phrase "containing only one reactive carboxyl group" should be understood as meaning that the carboxylic acid, as the end-capping agent, can contain one, two, or more carboxyl groups and / or other derived functional groups, but only one of them possesses the activity to react with the growing ends of the polyamide chains.

[0042] The carboxylic acid capping agent is preferably, but not limited to, at least one of acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, dodecanoic acid, stearic acid, cyclohexanoic acid, and benzoic acid.

[0043] The content of the carboxylic acid end-capping agent is not less than 0.1 mol / % based on the total amount of dicarboxylic acid reactive monomers constituting the first polyamide or the second polyamide; preferably, the content of the carboxylic acid end-capping agent is not less than 0.5 mol / % based on the total amount of dicarboxylic acid reactive monomers constituting the first polyamide or the second polyamide; more preferably, the content of the carboxylic acid end-capping agent is not less than 0.8 mol / % based on the total amount of dicarboxylic acid reactive monomers constituting the first polyamide or the second polyamide; particularly preferably, the content of the carboxylic acid end-capping agent is not less than 1.0 mol / % based on the total amount of dicarboxylic acid reactive monomers constituting the first polyamide or the second polyamide; generally... In this case, the content of the carboxylic acid end-capping agent is not higher than 6.0 mol / % based on the total amount of dicarboxylic acid reactive monomers constituting the first polyamide or the second polyamide; preferably, the content of the carboxylic acid end-capping agent is not higher than 5.8 mol / % based on the total amount of dicarboxylic acid reactive monomers constituting the first polyamide or the second polyamide; more preferably, the content of the carboxylic acid end-capping agent is not higher than 5.5 mol / % based on the total amount of dicarboxylic acid reactive monomers constituting the first polyamide or the second polyamide; particularly preferably, the content of the carboxylic acid end-capping agent is not higher than 5.0 mol / % based on the total amount of dicarboxylic acid reactive monomers constituting the first polyamide or the second polyamide.

[0044] The first or second polyamide is manufactured by melt polymerization, for example, by continuously removing water from a solution containing dicarboxylic acid and hexamethylenediamine under increasing temperature and pressure. Alternatively, hexamethylenediamine can be added to molten dicarboxylic acid for polycondensation. To maintain a uniform liquid phase, it is advisable to gradually and continuously add hexamethylenediamine to molten dicarboxylic acid. During the polymerization reaction, the temperature is continuously increased and adjusted to ensure that the temperature is not lower than the melting point of the polyamide oligomer and the polyamide product for polycondensation.

[0045] Specifically, the preparation method of the first polyamide or the second polyamide includes the following steps:

[0046] Hexamethylenediamine, terephthalic acid, isophthalic acid, end-capping agent, and deionized water are added to a reaction vessel under a nitrogen atmosphere and a pressure of 2.5-3 MPa. The reaction vessel is heated to 160-200℃ and reacted for 0.5-1.5 h, and then the temperature is further increased to 220-240℃ and reacted for 10-15 h to obtain the first polyamide or the second polyamide.

[0047] Specifically, the viscosity values ​​of the first polyamide or the second polyamide are each independently 1.8-2.4, for example, but not limited to 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4; the test method is ISO307:2019, and the test solvent is sulfuric acid.

[0048] In some embodiments, the flame retardant is aluminum diethylphosphinate.

[0049] Specifically, the K value of the polyvinylpyrrolidone is 10-120, for example, but not limited to 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120.

[0050] In some embodiments, the filler is at least one of fibrous filler and non-fibrous filler; the fibrous filler is selected from at least one of glass fiber, carbon fiber, and organic fiber, and the non-fibrous filler is selected from at least one of granular filler, layered filler, and nanofiller.

[0051] Specifically, the filler is glass fiber; the glass fiber can be formed using A-glass, C-glass, D-glass, E-glass, M-glass, R-glass, S-glass or mixtures thereof, preferably E-glass.

[0052] Specifically, glass fibers can be selected from different forms, including continuous glass fibers, chopped glass fibers (cut into sizes of 1-10 mm) and finely ground glass fibers (ground into sizes of 10-500 μm). Different forms of glass fibers can be used in combination.

[0053] Specifically, the glass fibers can be selected from different cross-sectional shapes, preferably but not limited to circular, elliptical, and quasi-rectangular cross-sectional shapes, more preferably non-circular cross-sectional morphologies, and particularly preferably quasi-rectangular cross-sectional morphologies. The described quasi-rectangular shape should be understood as having a general shape similar to a rectangle, with the main variation being that the right angles of the rectangle are replaced with rounded corners with a certain curvature. The reciprocal of the curvature is not greater than 50% of the long diameter of the quasi-rectangular shape; preferably, the reciprocal of the curvature is not greater than 25% of the long diameter of the quasi-rectangular shape; more preferably, the reciprocal of the curvature is not greater than 10% of the long diameter of the quasi-rectangular shape; particularly preferably, the reciprocal of the curvature is not greater than 12.5% ​​of the long diameter of the quasi-rectangular shape; simultaneously, the reciprocal of the curvature is not less than 8% of the short diameter of the quasi-rectangular shape; preferably, the reciprocal of the curvature is not less than 12.5% ​​of the short diameter of the quasi-rectangular shape; more preferably, the reciprocal of the curvature is not less than 25% of the short diameter of the quasi-rectangular shape; particularly preferably, the reciprocal of the curvature is not less than 40% of the short diameter of the quasi-rectangular shape. According to a preferred embodiment, the glass fiber has a long diameter / short diameter ratio of 1.5-10 in a pseudo-rectangular cross-section; preferably, the long diameter / short diameter ratio is 2.5-8; more preferably, the long diameter / short diameter ratio is 2.5-5.

[0054] Specifically, the polyamide material disclosed herein contains not less than 20% by weight of glass fiber; preferably, it contains not less than 25% by weight of glass fiber; and the polyamide material disclosed herein contains not more than 65% by weight of glass fiber; preferably, the polyamide material disclosed herein contains not more than 60% by weight of glass fiber; more preferably, the polyamide material disclosed herein contains not more than 55% by weight of glass fiber.

[0055] The polyamide material disclosed herein may contain one, two, or more glass fibers in terms of composition, form, and cross-sectional morphology. When two or more glass fibers are present, the total content of the glass fibers still falls within the aforementioned range.

[0056] In some embodiments, the polyamide material further includes 1-3 parts by weight of processing aids; the processing aids include at least one selected from heat stabilizers, antioxidants, nucleating agents, antistatic agents, foaming agents, lubricants, plasticizers, mold release agents, and pigments. Preferably, the polyamide material of this disclosure does not include processing aids.

[0057] The production method of the improved laser-weldable polyamide composite of the present invention is not particularly limited, and can be carried out using blending equipment such as a mixer, single-screw extruder, or twin-screw extruder. The order of addition of components is not particularly limited; they can be added simultaneously or in a specific order. Two or more components can be selected from all components for pre-mixing or mixing. For example, laser-transmitting colorant can be pre-formed into a masterbatch, which is then added to the melt of other components in a predetermined ratio before extrusion. Where the equipment's mixing capacity allows, the masterbatch and particles formed from other components can also be mixed and melt-processed in a predetermined ratio during molding or component production. The thermoplastic resin used in the masterbatch can be the polyamide resin described in this invention, or other polyamide resins, preferably PA6 or PA66. To overcome the breakage of glass fiber and flame retardant during extrusion, it is preferable to add them in a predetermined ratio in the middle of the extrusion equipment after the other components have fully formed a melt.

[0058] Specifically, the preparation method of the semi-aromatic polyamide material includes the following steps:

[0059] After the first polyamide, the second polyamide, and polyvinylpyrrolidone are mixed evenly, the resulting mixture is added to the main feeding system of the extruder for melt mixing. The flame retardant is added to the first side feeding system of the extruder, and the glass fiber is added to the second side feeding system of the extruder. The mixture is then extruded and granulated to obtain a semi-aromatic polyamide material.

[0060] In some embodiments, the temperature of the melt extrusion granulation is 290-340°C; for example, it can be, but is not limited to, 290°C, 295°C, 300°C, 310°C, 320°C, 325°C, 330°C, 335°C, or 340°C.

[0061] Thirdly, the application of the aforementioned polyamide material in the preparation of laser-welded parts is provided.

[0062] Fourthly, a laser-welded component is provided, the laser-welded component comprising the aforementioned polyamide material.

[0063] Laser-welded components include the aforementioned polyamide material (i.e., a laser-transmitting resin material) and another laser-absorbing resin material. The laser penetrates the transmitting resin material and irradiates the absorbent resin material adhering thereto. The laser energy accumulated on the contact surface of the absorbent resin material heats and melts the contact area. The transmitting resin material is also heated / melted through heat transfer, thereby allowing the resin materials to bond easily and firmly together. The laser can directly irradiate the welding area or can be guided to the contact area using optical devices such as mirrors or optical fibers. These and other techniques may be appropriately employed depending on the individual welding operation and selected by those skilled in the art. If necessary, pressure may be further applied to the bonding surfaces.

[0064] The laser-absorbing resin can be polyamide resin, polyester resin, polycarbonate resin, polyolefin resin, styrene resin, polyphenylene ether resin, polyvinyl resin, acrylic resin, acetal resin, etc. To achieve stronger welding performance and considering compatibility, the laser-absorbing resin is a polyamide resin.

[0065] There is no particular limitation on the type of polyamide resin used as the laser-absorbing resin; it can be any polyamide resin other than the semi-aromatic polyamide material disclosed herein.

[0066] A useful laser for welding the molded resin products of the present invention can be any laser that emits light in the near-infrared region. In particular, lasers emitting light with wavelengths of 800-1200 nm are preferred, especially diode lasers and YAG lasers. Lasers can be used alone or in combination with each other, as those skilled in the art of laser operation will understand. Laser emission can be continuous or pulsed, with continuous emission being preferred.

[0067] The intensity, density, and irradiation area of ​​the laser are selected to appropriately heat and melt the bonding surfaces. These are adjusted in such a way that the resulting adhesive has the strength required for the application of interest. If it is too weak, sufficient heating and melting cannot be achieved. Conversely, if it is too strong, it may lead to resin degradation.

[0068] This invention relates to the joining portion of two molded parts (one transmitting a laser and the other absorbing a laser) placed in contact with each other, wherein a predetermined amount of laser beam is focused and transmitted to melt and bond the joining portion. If multiple points, lines, or surfaces are to be welded, the laser can be moved sequentially to irradiate the joining surfaces, or multiple laser sources can be used to irradiate simultaneously.

[0069] The laser-welded components disclosed herein can be semi-finished products, finished products, or components forming them. Unlike traditional joining methods, the laser-welded components of this invention possess high mechanical properties, flame retardancy, solvent resistance, strong bond strength, require little or no post-processing, and suffer no significant thermal or mechanical damage. They can be applied to components in new energy vehicle battery systems and thermal management systems that require coolant resistance and flame retardancy, such as electronic water pumps, electronic cooling pipe connectors, and 12V battery housings.

[0070] The raw materials used in the embodiments and comparative examples are described below, but are not limited to these materials:

[0071] First polyamide:

[0072] PA6T / 6I-1 was prepared in-house, and its preparation method is as follows:

[0073] Hexamethylenediamine, dicarboxylic acids, benzoic acid, and deionized water were added to a reactor under a nitrogen atmosphere and a pressure of 2.8 MPa. The reactor was heated to 180°C and reacted for 1 hour, then the temperature was further increased to 235°C and reacted for 12 hours to obtain PA6T / 6I-1. The dicarboxylic acids were terephthalic acid and isophthalic acid. Assuming the total molar content of the dicarboxylic acids was 100%, the molar content of terephthalic acid was 70%, and the molar content of isophthalic acid was 30%. The ratio of the total molar content of the dicarboxylic acids to the molar content of hexamethylenediamine was 1:1, and the molar content of benzoic acid was 1% of the total molar content of the dicarboxylic acids.

[0074] PA6T / 6I-2 is prepared in-house. The only difference between it and PA6T / 6I-1 is that the molar content of terephthalic acid is 65% and the molar content of isophthalic acid is 35%. All other aspects are the same.

[0075] PA6T / 6I-3 is prepared in-house. The only difference between it and PA6T / 6I-1 is that the molar content of terephthalic acid is 60% and the molar content of isophthalic acid is 40%. All other aspects are the same.

[0076] PA6T / 6I-4 is prepared in-house. The only difference between it and PA6T / 6I-1 is that the molar content of terephthalic acid is 80% and the molar content of isophthalic acid is 20%. All other aspects are the same.

[0077] PA6T / 6I-5 is prepared in-house. The only difference between it and PA6T / 6I-1 is that the molar content of terephthalic acid is 50% and the molar content of isophthalic acid is 50%. All other aspects are the same.

[0078] Second polyamide:

[0079] PA6I / 6T-1 is self-made. Its preparation method is the same as PA6T / 6I-1, except that the molar content of terephthalic acid is 30% and the molar content of isophthalic acid is 70%.

[0080] PA6I / 6T-2 is prepared in-house. The only difference between it and PA6T / 6I-1 is that the molar content of terephthalic acid is 35% and the molar content of isophthalic acid is 65%. All other aspects are the same.

[0081] PA6I / 6T-3 is prepared in-house. The only difference between it and PA6T / 6I-1 is that the molar content of terephthalic acid is 40% and the molar content of isophthalic acid is 60%. All other aspects are the same.

[0082] Flame retardant: aluminum diethylphosphinate, Clariant;

[0083] Filler: Glass fiber, ECS301HP, average length 3mm, Chongqing International Composite Materials Co., Ltd.

[0084] Polyvinylpyrrolidone: PVP K25, Huzhou Shenhua Polymer;

[0085] PA66: U4800, what?

[0086] Examples and Comparative Examples

[0087] The components and weight parts of the semi-aromatic polyamide materials in the examples and comparative examples are shown in Tables 1 and 2. The preparation methods of the semi-aromatic polyamide materials in the examples and comparative examples include the following steps:

[0088] According to Tables 1 and 2, the first polyamide, the second polyamide, and polyvinylpyrrolidone were mixed evenly, and the resulting mixture was added to the main feeding system of the extruder for melt mixing. The flame retardant was added to the first side feeding system of the extruder, and the glass fiber was added to the second side feeding system of the extruder. The mixture was then extruded and granulated to obtain a semi-aromatic polyamide material. The twin-screw extruder had a length-to-diameter ratio of 52:1, a screw speed of 200 rpm, an extrusion temperature of 290-340℃, and a feeding speed of 350 kg / h.

[0089] The semi-aromatic polyamide materials obtained in the examples and comparative examples were subjected to performance tests, and the test methods are as follows:

[0090] (1) Coolant retention rate: The semi-aromatic polyamide material injection molding standard tensile specimen was made according to ISO 527-1 / -2 and the strength test was carried out according to the standard. This is the initial tensile strength A1. Then the tensile specimen was placed in ethylene glycol / water solution with a volume ratio of ethylene glycol to water of 1:1 and placed in a sealed container at 150°C for 96 hours. After the tensile specimen was taken out, the tensile strength test was carried out according to ISO 527-1 / -2. This is the tensile strength A2 after being immersed in coolant. A2 / A1 is the coolant retention rate.

[0091] (2) Light transmittance: The semi-aramid material was injection molded into a square plate of 100mm*100mm*2mm, and the light transmittance at 960mm was tested using a light transmittance tester.

[0092] (3) Flame retardancy: Referring to the UL94 V-0 test standard, a standard strip sample with a length of 125±5mm, a width of 13.0±0.5mm and a thickness of 3.0mm was injection molded from semi-aromatic polyamide material. Five standard strip samples were placed at a temperature of 23℃ and a humidity of 50% for 48h.

[0093] Point the Bunsen burner flame at the center of the lower end of the sample, maintaining a distance of 10±1 mm between the center of the top surface of the Bunsen burner and the lower end of the sample. Maintain this distance for 10±0.5 s. If necessary, move the Bunsen burner according to the length and position of the sample. After applying the flame to the sample for 10±0.5 s, immediately withdraw the Bunsen burner at a rate of approximately 300 mm / s to a distance of at least 150 mm from the sample. Simultaneously, use a timing device to measure the flaming combustion time T1 (in seconds) of the sample. After the flaming combustion of the sample stops, even if the Bunsen burner has not been withdrawn at least 150 mm from the sample, immediately move the Bunsen burner nozzle to the lower end of the sample, maintaining a distance of 10±1 mm, and apply the flame again for 10±0.5 s. If necessary, remove the Bunsen burner to remove any drippings. Immediately after applying the flame, withdraw the Bunsen burner at least 150 mm away from the sample. Simultaneously, start the timing device to measure the flaming time T2 and the flameless combustion time T3 of the sample, and record T2 and T3. If the T1+T2+T3 values ​​of all 5 splines are less than 10s, and no dripping ignites the cotton below, then the V-0 condition is considered to be satisfied.

[0094] (4) Laser welding strength: The semi-aramid material was injection molded into a square plate of 50mm*50mm*2mm and welded under the condition of wavelength of 960mm, welding speed of 500mm / s, welding pressure of 3bar, welding time of 2s, and welding power of 80W to obtain the welded sample. The destructive force test of the welded sample was carried out using ISO 527-1 / -2 method to obtain the laser welding strength.

[0095] The test results are shown in Tables 1 and 2.

[0096] Table 1

[0097]

[0098]

[0099] Table 2

[0100]

[0101]

[0102] The experimental data in Tables 1 and 2 show that the semi-aromatic polyamide material disclosed in this invention has a coolant retention rate of 69.5-83.1%, a flame retardancy of V-0, a light transmittance of 35.2-45.3%, and a laser welding strength of 1528-2098 N. This indicates that the semi-aromatic polyamide material disclosed in this invention has high solvent resistance, flame retardancy, light transmittance, and laser welding strength.

[0103] Comparing Examples 1, 3-4, and 1-2, it can be seen that, with the total molar content of dicarboxylic acids being 100%, the molar content of terephthalic acid in the first polyamide is 60-70%. The resulting semi-aromatic polyamide material exhibits a coolant retention rate of 69.5-80.3%, a flame retardancy of V-0, a light transmittance of 39.5-44.3%, and a laser welding strength of 1833-1995 N. This indicates that the obtained semi-aromatic polyamide material has high solvent resistance, flame retardancy, light transmittance, and laser welding strength.

[0104] Comparative Examples 1 and 3 show that when PA66 is used as the first polyamide, the resulting semi-aromatic polyamide material has a coolant retention rate of 30.3% and a flame retardancy of V-2. This indicates that using PA66 as the first polyamide will lead to a decrease in the solvent resistance and flame retardancy of the semi-aromatic polyamide material.

[0105] Comparative Examples 1, 7-9, and 5-6 show that when the weight of the second polyamide is 5-10 parts, the resulting semi-aromatic polyamide material exhibits a coolant retention rate of 70.4-83.1%, a flame retardancy of V-0, a light transmittance of 35.3-45.3%, and a laser welding strength of 1528-2098 N. When the weight of the second polyamide is 6.5-8 parts, the resulting semi-aromatic polyamide material exhibits a coolant retention rate of 80.3-83.1%, a flame retardancy of V-0, a light transmittance of 36.2-39.5%, and a laser welding strength of 1621-1833 N. This indicates that when the weight of the second polyamide is 6.5-8 parts, the resulting semi-aromatic polyamide material has higher solvent resistance, flame retardancy, light transmittance, and laser welding strength.

[0106] Comparing Example 1 and Comparative Example 7, it can be seen that without polyvinylpyrrolidone, the light transmittance of the resulting semi-aromatic polyamide material is 30%, and the laser welding strength is 1000N. This indicates that the lack of polyvinylpyrrolidone will lead to a significant decrease in the light transmittance and laser welding strength of the semi-aromatic polyamide material.

[0107] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of this disclosure and not to limit the scope of protection of this disclosure. Although this disclosure has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this disclosure without departing from the substance and scope of the technical solutions of this disclosure.

Claims

1. A semi-aromatic polyamide material, characterized in that, It includes the following components in parts by weight: 45-62 parts of primary polyamide, 5-10 parts of secondary polyamide, 3-5 parts of polyvinylpyrrolidone, 10-12 parts of flame retardant, and 20-30 parts of filler; In this embodiment, both the first polyamide and the second polyamide are copolymers of dicarboxylic acid and hexamethylenediamine, and the dicarboxylic acid is terephthalic acid and isophthalic acid; Based on a total molar content of 100% for dicarboxylic acids, the first polyamide comprises repeating units derived from the following: 60-70% molar content of terephthalic acid and 30-40% molar content of isophthalic acid; the second polyamide comprises repeating units derived from the following: 30-40% molar content of terephthalic acid and 60-70% molar content of isophthalic acid.

2. The semi-aromatic polyamide material as described in claim 1, characterized in that, The molar content of terephthalic acid in the first polyamide is 65-70%.

3. The semi-aromatic polyamide material as described in claim 1, characterized in that, The second polyamide is 6.5-8 parts by weight.

4. The semi-aromatic polyamide material as described in claim 1, characterized in that, The flame retardant is aluminum diethylphosphinate.

5. The semi-aromatic polyamide material as described in claim 1, characterized in that, The filler is at least one of fibrous filler and non-fibrous filler; the fibrous filler is selected from at least one of glass fiber, carbon fiber and organic fiber, and the non-fibrous filler is selected from at least one of granular filler, layered filler and nano filler.

6. The semi-aromatic polyamide material as described in claim 1, characterized in that, The semi-aromatic polyamide material further includes 1-3 parts by weight of processing aids; the processing aids include at least one of heat stabilizers, antioxidants, nucleating agents, antistatic agents, foaming agents, lubricants, plasticizers, release agents, and pigments.

7. A method for preparing a semi-aromatic polyamide material as described in any one of claims 1-6, characterized in that, Includes the following steps: After the components are mixed evenly in proportion, they are melt-extruded and granulated to obtain a semi-aromatic polyamide material.

8. The method for preparing the semi-aromatic polyamide material as described in claim 7, characterized in that, The temperature for melt extrusion granulation is 290-340℃.

9. The application of the semi-aromatic polyamide material as described in any one of claims 1-6 in the preparation of laser-welded parts.

10. A laser-welded component, characterized in that, The laser-welded components include the semi-aromatic polyamide material as described in any one of claims 1-6.

Images