High temperature and high humidity resistant nylon composition, and preparation method and application thereof

Abstract

The application discloses a high-temperature and high-humidity resistant nylon composition and a preparation method and application thereof, and belongs to the technical field of high polymer materials. The nylon composition comprises the following components in parts by weight: 34-46 parts of an aliphatic PA resin, 5-12 parts of transparent nylon, 25-35 parts of modified glass fiber, 16-22 parts of a flame retardant, and 1-8 parts of an auxiliary agent; the modified glass fiber is glass fiber modified by an ionic liquid and a metal salt; by introducing the transparent nylon and the modified glass fiber, the mechanical property, the high-temperature and high-humidity resistance and the color stability of the nylon composition can be effectively improved, so that the nylon composition is very suitable for preparing automobile accessory products or electronic and electrical products.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a high-temperature and high-humidity resistant nylon composition, its preparation method, and its application. Background Technology

[0002] New energy vehicles have become a hot development area, bringing excellent development opportunities to fields such as power batteries, charging piles, and electronic appliances. Flame-retardant materials have been widely used in these fields, and while controlling their room-temperature mechanical properties, higher requirements are being placed on their high-temperature and high-humidity aging performance and color stability.

[0003] Nylon, abbreviated as polyamide (PA), is a general term for thermoplastic resins containing repeating amide groups (-NHCO-) ​​in their molecular backbone. It includes aliphatic nylon, aromatic nylon, semi-aromatic nylon, and new specialty nylon varieties. Nylon materials possess excellent mechanical properties and are widely used in the automotive industry. However, nylon materials are prone to water absorption and yellowing, and their performance deteriorates easily under high temperature, high humidity, and light exposure. Commonly available flame-retardant reinforced nylon 66 materials primarily focus on flame retardancy, with relatively low requirements for high temperature and moisture resistance, and little attention paid to color stability. For example, invention patent CN101531810A discloses a halogen-free flame-retardant glass fiber reinforced thermoplastic engineering plastic nylon 66, which exhibits good thermal stability, excellent mechanical properties, superior electrical properties, and good flame retardancy, but does not investigate the material's color changes. The invention patent with publication number CN102634205A discloses an antibacterial nylon composite material. Although it has excellent mechanical properties, such as tensile strength greater than 135MPa, flexural strength greater than 205MPa, melt index greater than 21g / 10min, and resistance to bacterial erosion, its resistance to high temperature and high humidity is poor.

[0004] Therefore, there is an urgent need to develop a nylon material that is resistant to high temperatures and humidity and has good color stability to meet the current performance requirements of the automotive industry for nylon materials. Summary of the Invention

[0005] Based on the deficiencies of existing technologies, the purpose of this invention is to provide a high-temperature and high-humidity resistant nylon composition, its preparation method, and its application. By introducing transparent nylon and modified glass fiber, this invention can effectively improve the mechanical properties, high-temperature and high-humidity resistance, and color stability of the nylon composition.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a high-temperature and high-humidity resistant nylon composition comprising the following components in parts by weight:

[0008] Aliphatic PA resin 34-46 parts, transparent nylon 5-12 parts, modified glass fiber 25-35 parts, flame retardant 16-22 parts, additives 1-8 parts;

[0009] The modified glass fiber is a composite modified glass fiber of ionic liquid and metal salt, and the weight ratio of ionic liquid, metal salt and glass fiber is ionic liquid: metal salt: glass fiber = (0.5-3):(0.1-0.3):10; the metal salt includes at least one of sodium salt, calcium salt and zinc salt.

[0010] The transparent nylon includes at least one of poly(hexamethylene isophthalamide) (PA6I) and PA6i / 6T.

[0011] This invention, by introducing transparent nylon and modified glass fiber, can not only effectively improve the mechanical properties of nylon compositions, but also effectively improve the high temperature and high humidity resistance and color stability of nylon compositions.

[0012] Modified glass fiber is glass fiber modified by ionic liquid and metal salt, which can effectively improve the polarity of the glass fiber surface, making the modified glass fiber more compatible with components such as aliphatic PA resin and transparent nylon, and can effectively improve the high temperature and moisture resistance and color stability of nylon composition.

[0013] The inventors discovered that transparent nylon contains benzene ring groups, which restrict the movement of aliphatic PA resin molecular chains in the nylon composition, hinder the crystallization of aliphatic PA resin, thereby improving the performance of the nylon composition and reducing its hygroscopicity.

[0014] In this invention, the aliphatic PA resin accounts for not less than 37% by weight in the nylon composition.

[0015] In this invention, the modified glass fiber is obtained by surface modification of glass fiber raw material through ionic liquid and metal salt coating. The glass fiber raw material has an average diameter of 7-14 μm and a length of 1-5 mm. The average diameter is measured by projection microscopy.

[0016] In a preferred embodiment of the present invention, the ionic liquid is an imidazole ionic liquid, and the imidazole ionic liquid is preferably 1-butyl-3-methylimidazolium chloride.

[0017] In a preferred embodiment of the present invention, the metal salt is an alkali metal halide, and more preferably calcium chloride.

[0018] As a preferred embodiment of the present invention, the method for preparing the modified glass fiber includes the following steps: dissolving ionic liquid and metal salt in water, mixing and treating at 50-70°C for 30-60 minutes, then uniformly spraying the mixture onto the surface of glass fiber, and drying the mixture to obtain the modified glass fiber.

[0019] In a preferred embodiment of the present invention, the relative viscosity of the aliphatic PA resin is 2.4-3.2.

[0020] In a preferred embodiment of the present invention, the relative viscosity of the transparent nylon is 1-3.

[0021] In this invention, the method for determining relative viscosity is as follows: according to the ISO 307-2007 standard, the sample to be tested is dissolved in 96% concentrated sulfuric acid to prepare a sample solution of 1 g / mL, and then the viscosity of the sample is tested using Ubbelohde viscositometer.

[0022] In this invention, the aliphatic PA resin may be at least one of polyhexamethylene adipamide, polydecanoyl decanoyl diamine, polydodecanediamide, and polydecanoyl hexamethylene diamine.

[0023] In a preferred embodiment of the present invention, the flame retardant includes an organophosphorus halogen-free flame retardant; for example, the organophosphorus halogen-free flame retardant is a phosphate ester halogen-free flame retardant.

[0024] In a preferred embodiment of the present invention, the additives include at least one of the following: color-fixing agent, light-blocking agent, acid absorber, antioxidant, lubricant, and light stabilizer.

[0025] Furthermore, the fixing agent is an acidic fixing agent, preferably a high molecular weight aromatic sulfonic acid condensate. Using a high molecular weight aromatic sulfonic acid condensate as a fixing agent can better improve the color stability of the nylon composition.

[0026] The light-blocking agent is a metallic light-blocking agent, preferably titanium dioxide.

[0027] The acid absorbent is a hydrotalcite-based inorganic oxide.

[0028] In this invention, the antioxidant may be at least one of phosphite antioxidants and hindered phenolic antioxidants; the lubricant may be silicone masterbatch; and the light stabilizer may be at least one of benzotriazole light stabilizers and hindered amine light stabilizers.

[0029] The inventors discovered that the addition of a light-blocking agent can further reduce the impact of ultraviolet light on the color of the composition; the addition of an acid-absorbing agent helps to absorb acids in the composition system, improving the composition's high-temperature and moisture resistance and color stability; the fixing agent has good compatibility with aliphatic PA resin and transparent nylon, and the acidic groups contained in the fixing agent can combine with the amino groups of aliphatic PA resin and transparent nylon to form a network structure, thereby improving stability.

[0030] In a preferred embodiment of the present invention, the weight parts of each component of the additives in the high temperature and high humidity resistant nylon composition are as follows: 0.2-0.8 parts of color fixing agent, 0.2-0.8 parts of light-blocking agent, 0.6-3 parts of acid absorber, 0.1-0.5 parts of antioxidant, 0.3-1 parts of lubricant, and 0.3-1 parts of light stabilizer.

[0031] Based on the needs of practical applications, those skilled in the art may appropriately introduce some common auxiliary components, such as antioxidants to improve the aging resistance of the composition, lubricants to improve the processing performance of the composition, light stabilizers to improve the light stability of the composition, and color powders to impart color to the composition, etc., provided that they do not adversely affect the performance of the nylon composition.

[0032] In a preferred embodiment of the present invention, the high-temperature and high-humidity resistant nylon composition comprises the following components in parts by weight:

[0033] The composition includes 38-44 parts aliphatic PA resin, 8-10 parts transparent nylon, 30-34 parts modified glass fiber, 18-20 parts flame retardant, 0.3-0.5 parts color fixing agent, 0.3-1 part light-blocking agent, 1-2 parts acid absorber, 0.1-0.2 parts antioxidant, 0.3-0.5 parts lubricant, and 0.3-0.5 parts light stabilizer.

[0034] In a second aspect, the present invention provides a method for preparing a high-temperature and high-humidity resistant nylon composition as described in the first aspect, comprising the following steps:

[0035] All components except modified glass fiber and flame retardant are mixed and fed into a twin-screw extruder through the main feed port. Modified glass fiber and flame retardant are added into the twin-screw extruder through the side feed port. The mixture is melted, extruded and granulated to obtain the high-temperature and high-humidity resistant nylon composition.

[0036] Thirdly, the present invention provides the application of a high-temperature and high-humidity resistant nylon composition as described in the first aspect in the preparation of automotive parts or electronic and electrical products.

[0037] The automotive parts products can be components such as automotive connectors, electronic control boxes, and sensors.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] This invention, by introducing transparent nylon, modified glass fiber, color-fixing agent, and light-blocking agent, can effectively improve the mechanical properties, high temperature and high humidity resistance, and color stability of nylon compositions. The nylon compositions provided by this invention are very suitable for manufacturing automotive parts or electronic and electrical products. Detailed Implementation

[0040] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this invention are commonly used reagents and instruments.

[0041] The source information and performance parameters of the components described in each embodiment and comparative example are shown in Table 1 below.

[0042] Table 1

[0043]

[0044]

[0045] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0046] Examples 1-13

[0047] Examples of the high-temperature and high-humidity resistant nylon composition of the present invention are shown in Table 2, and the components and their weight ratios of the high-temperature and high-humidity resistant nylon composition are shown in Table 2.

[0048] The preparation method of the high-temperature and high-humidity resistant nylon composition includes the following steps:

[0049] All components except modified glass fiber and flame retardant are mixed and fed into a twin-screw extruder through the main feed port. Modified glass fiber and flame retardant are added into the twin-screw extruder through the side feed port. The mixture is melted, extruded and granulated to obtain the high temperature and high humidity resistant nylon composition.

[0050] During melt extrusion, the temperature zones of the twin-screw extruder from the feeding section to the die head are: Zone 1 230℃±10℃, Zone 2 240℃±10℃, Zone 3 245℃±10℃, Zone 4 250℃±10℃, Zone 5 255℃±10℃, Zone 6 260℃±10℃, Zone 7 250℃±10℃, the screw speed is 300 rpm, and the screw length-to-diameter ratio is 40:1.

[0051] Table 2 (Unit: parts by weight)

[0052]

[0053]

[0054] Comparative Examples 1-6

[0055] The only difference between each comparative example and the embodiment is the type and ratio of components, as shown in Table 3.

[0056] Table 3 (Unit: parts by weight)

[0057]

[0058] To verify the performance of the nylon composition described in this invention, the nylon compositions prepared in each embodiment and comparative example were subjected to the following performance tests, with the specific steps as follows:

[0059] (1) Tensile strength: The sample was injection molded into a dumbbell-shaped strip of 170mm*10mm*4mm and tested according to ISO 527-2012 method. The tensile rate was 5mm / min.

[0060] (2) Notched impact strength of simply supported beam: The sample was injection molded into a 80mm*10mm*4mm strip with an 8mm thickness at the notch. It was tested according to ISO 179 / 1eA-2020 method, and the pendulum energy was 4J.

[0061] (3) Evaluation of high temperature and high humidity resistance: The sample was injection molded into a dumbbell-shaped strip of 170mm*10mm*4mm. The sample was placed in a high temperature and high humidity chamber of 85℃ and 85%RH. After aging for 1000H, the tensile strength was tested according to ISO 527-2012 method, and the tensile rate was 5mm / min. The sample was injection molded into a strip of 80mm*10mm*4mm with a notch thickness of 8mm. The notched impact strength of the simply supported beam was tested according to ISO 179 / 1eA method, with a pendulum energy of 4J. The tensile strength retention rate and notched impact strength retention rate after aging were calculated. Tensile strength retention rate = tensile strength measured after aging / tensile strength measured in step (1) * 100%. Notched impact strength retention rate = notched impact strength measured after aging / notched impact strength measured in step (2) * 100%.

[0062] (4) Color stability evaluation: According to the requirements of automotive exterior trim, in accordance with the J2527-2004 standard, a 50*70mm sample was prepared and placed in a xenon lamp aging chamber for 1000 hours of light aging. Then, the color change of the sample was evaluated, the color stability was assessed, and the change of gray level was recorded. The highest gray level is 5 and the lowest is 1. The higher the value, the smaller the color change of the material after xenon lamp aging, indicating that the color is more stable.

[0063] The test results are shown in Table 4-5.

[0064] Table 4

[0065]

[0066] Table 5

[0067]

[0068]

[0069] As can be seen from Examples 1-13, the present invention introduces a composite of transparent nylon and modified glass fiber. The resulting nylon composition not only possesses excellent mechanical properties, but also excellent resistance to high temperature and humidity, as well as color stability. Its tensile strength is not less than 144 MPa, and its notched impact strength is not less than 8.2 KJ / m. 2 After photoaging under high temperature and humidity conditions, the tensile strength retention rate is above 64.9%, and the grayscale level is not lower than 3-4. Under high temperature conditions, the transparent nylon contains amide bonds, which can absorb water. After water absorption, the notched impact strength of the material increases, resulting in a notched impact strength retention rate of over 193%. Therefore, the nylon composition provided by this invention is very suitable for manufacturing automotive parts or electronic and electrical products.

[0070] As can be seen from Example 1 and Comparative Example 1, the present invention introduces transparent nylon. The benzene ring groups contained in the transparent nylon can effectively restrict the movement of aliphatic PA resin molecular chains in the nylon composition, hinder the crystallization of aliphatic PA resin, and make the mechanical properties of the nylon composition better.

[0071] As can be seen from Examples 1, 12-13, Comparative Examples 2 and 5-6, the present invention uses metal salts and ionic liquids to modify the surface of glass fibers, which can more effectively improve the polarity of the glass fiber surface, making the modified glass fibers more compatible with components such as aliphatic PA resin and transparent nylon, thereby more effectively improving the mechanical properties and color stability of the nylon composition.

[0072] As can be seen from Examples 1, 9-11 and Comparative Examples 3-4, the weight ratio of ionic liquid, metal salt and glass fiber is more suitable when controlled at ionic liquid: metal salt: glass fiber = (0.5-3):(0.1-0.3):10, more preferably (1-2):(0.2-0.25):10, and the mechanical properties, high temperature and high humidity light aging resistance and color stability of the nylon composition are significantly better.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention 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 the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-temperature and high-humidity resistant nylon composition, characterized in that, The components include the following parts by weight: Aliphatic PA resin 34-46 parts, transparent nylon 5-12 parts, modified glass fiber 25-35 parts, flame retardant 16-22 parts, additives 1-8 parts; The modified glass fiber is a composite modified glass fiber of ionic liquid and metal salt, and the weight ratio of ionic liquid, metal salt and glass fiber is ionic liquid: metal salt: glass fiber = (0.5-3):(0.1-0.3):10; the metal salt is zinc salt and the metal salt is metal halide; The transparent nylon is PA6I; The flame retardant is an organophosphorus halogen-free flame retardant.

2. The high-temperature and high-humidity resistant nylon composition as described in claim 1, characterized in that, The ionic liquid includes imidazole ionic liquids.

3. The high-temperature and high-humidity resistant nylon composition as described in claim 2, characterized in that, The imidazole ionic liquid is 1-butyl-3-methylimidazolium chloride.

4. The high-temperature and high-humidity resistant nylon composition as described in claim 1, characterized in that, The relative viscosity of the aliphatic PA resin is 2.4-3.

2. The method for determining the relative viscosity is as follows: according to the ISO 307-2007 standard, the sample to be tested is dissolved in 96% concentrated sulfuric acid to prepare a sample solution of 1 g / mL, and then the viscosity of the sample is tested using Ubbelohde viscositometer.

5. The high-temperature and high-humidity resistant nylon composition as described in claim 1, characterized in that, The additives include at least one of the following: color-fixing agents, light-blocking agents, acid absorbers, antioxidants, lubricants, and light stabilizers.

6. The high-temperature and high-humidity resistant nylon composition as described in claim 5, characterized in that, The additives include the following components in parts by weight: 0.3-0.8 parts of color-fixing agent, 0.3-0.8 parts of opaque agent, and 1-3 parts of acid absorbent.

7. The high-temperature and high-humidity resistant nylon composition as described in claim 6, characterized in that, The additives also include the following components in parts by weight: 0.1-0.5 parts antioxidant, 0.3-1 parts lubricant, and 0.3-1 parts light stabilizer.

8. A method for preparing a high-temperature and high-humidity resistant nylon composition as described in any one of claims 1 to 7, characterized in that, Includes the following steps: All components except modified glass fiber and flame retardant are mixed and fed into a twin-screw extruder through the main feed port. Modified glass fiber and flame retardant are added into the twin-screw extruder through the side feed port. The mixture is melted, extruded and granulated to obtain the high-temperature and high-humidity resistant nylon composition.

9. The use of the high-temperature and high-humidity resistant nylon composition according to any one of claims 1 to 7 in the preparation of automotive parts or electronic and electrical products.

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