Fiber-free flame-retardant polyamide composition, and preparation method therefor and use thereof

Abstract

The present application relates to the technical field of engineering plastics. Disclosed are a fiber-free flame-retardant polyamide composition, and a preparation method therefor and the use thereof. The fiber-free flame-retardant polyamide composition comprises the following components, in parts by weight: 55-81 parts of a polyamide resin; 19-42 parts of a brominated flame retardant; 4-12 parts of zinc borate; 1-12 parts of antimony oxide; and 0.1-0.6 parts of zinc bromide, wherein the viscosity of the polyamide resin is 2.4-2.7. The fiber-free flame-retardant polyamide composition of the present invention can achieve the UL 94 5VA rating, and has improved flame retardant performance without compromising the surface glossiness and mirror effect thereof.

Description

A fiber-free flame-retardant polyamide composition, its preparation method and application Technical Field

[0001] This application relates to the technical field of engineering plastics, and more particularly to a fiber-free flame-retardant polyamide composition, its preparation method, and its application. Background Technology

[0002] Polyamide materials are widely used engineering plastics, possessing excellent heat resistance, solvent resistance, mechanical properties, and processing performance. They are widely applied in electronics, electrical engineering, rail transportation, power tools, home appliances, and sporting goods. With the development of the electronics and new energy industries, increasingly stringent requirements have been placed on the flame retardant properties of materials, such as the 5VA flame retardant requirement in the UL94 standard. Conventional 5VA flame-retardant nylon materials require the addition of glass fibers to the system to provide sufficient structural support during combustion, working in conjunction with the carbon layer to prevent burn-through. However, the addition of glass fibers rapidly degrades the surface finish of the parts, especially gloss and mirror-like properties, making them unsuitable for applications requiring high aesthetic standards. Summary of the Invention

[0003] The purpose of this application is to overcome the shortcomings of the prior art and provide a fiber-free flame-retardant polyamide composition, its preparation method, and its application. The fiber-free flame-retardant polyamide composition described in this application can achieve a 5VA flame retardant rating, improving flame retardant performance without affecting its appearance, gloss, and mirror finish.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0005] In a first aspect, this application provides a fiber-free flame-retardant polyamide composition comprising the following components in parts by weight:

[0006] The polyamide resin comprises 55-81 parts; a brominated flame retardant comprises 19-42 parts; zinc borate comprises 4-12 parts; antimony white comprises 1-12 parts; zinc bromide comprises 0.1-0.6 parts; and the viscosity of the polyamide resin is 2.4-2.7.

[0007] This application improves the flame retardant properties of the polyamide composition by adding zinc borate to the antimony bromide flame retardant system. The complexation effect with zinc bromide allows for a synergistic effect, rapidly forming a carbon layer of sufficient strength during combustion. This prevents the formation of voids due to melt collapse during combustion. If the viscosity of the polyamide resin is too high, the material becomes difficult to process; if the viscosity is too low, small molecules are more likely to form, thus affecting the flame retardant properties of the composition. Therefore, this application controls the viscosity of the polyamide resin within the aforementioned range, which is beneficial for further improving the flame retardant properties of the polyamide composition. Furthermore, improving the flame retardant properties does not affect its appearance, gloss, or mirror-like finish.

[0008] Preferably, the viscosity of the polyamide resin is a range of any one or both of 2.4, 2.5, 2.6, and 2.7.

[0009] The viscosity of the polyamide resin described in this application was measured at room temperature according to the test method of ISO 307-2019.

[0010] Preferably, the polyamide resin includes at least one of polycaprolactam (PA6, polyamide 6), polyhexamethylene adipamide (PA66, polyamide 66), and poly(hexamethylene terephthalamide / hexamethylene adipamide copolymer) (PA6T / 66).

[0011] Preferably, the brominated flame retardant includes at least one of brominated polystyrene, brominated epoxy, and decabromodiphenyl ethane.

[0012] More preferably, the brominated flame retardant includes brominated polystyrene and brominated epoxy, and the weight ratio of the brominated polystyrene to the brominated epoxy is greater than 2:1, specifically including but not limited to 3:1, 4:1, 5:1, and 6:1.

[0013] Preferably, the fiber-free flame-retardant polyamide composition comprises the following components in parts by weight:

[0014] 56-80 parts polyamide resin; 20-40 parts brominated flame retardant; 5-10 parts zinc borate; 2-10 parts antimony white; 0.1-0.5 parts zinc bromide.

[0015] Preferably, the average particle size of the zinc borate is 5-15 micrometers, the average particle size of the zinc bromide is 10-50 micrometers, and the average particle size of the antimony white is 0.5-5 micrometers.

[0016] The particle size of zinc borate, zinc bromide, or antimony white described in this application was tested according to ISO 13320-2020 standard.

[0017] Preferably, the fiber-free flame-retardant polyamide composition further includes 0.1-0.5 parts of an antioxidant.

[0018] More preferably, the antioxidant includes hindered phenolic antioxidants or hindered amine antioxidants.

[0019] The melt flow rate of the fiber-free flame-retardant polyamide composition described in this application is 5-50 g / 10 min. The melt flow rate was tested according to ISO-1-2022 standard.

[0020] Secondly, this application also discloses a method for preparing a fiber-free flame-retardant polyamide composition, comprising the following steps:

[0021] The components are mixed and added to a twin-screw extruder. After granulation and cooling, a fiber-free flame-retardant polyamide composition is obtained.

[0022] Preferably, the temperature of the twin-screw extruder is 190-275℃, and the screw speed is 300-500 rpm.

[0023] More preferably, the extrusion temperature of the twin-screw extruder is: 190℃ in zone 1, 260℃ in zone 2, 270℃ in zone 3, 275℃ in zone 4, 275℃ in zone 5, 275℃ in zone 6, 270℃ in zone 7, 270℃ in zone 8, and 270℃ in zone 9.

[0024] Thirdly, this application also discloses the application of a fiber-free flame-retardant polyamide composition in electronics, electrical engineering, and new energy.

[0025] Compared with the prior art, the beneficial effects of this application are as follows:

[0026] (1) This application improves the flame retardant properties of polyamide compositions by adding zinc borate to the antimony bromide flame retardant system and combining the complexation effect of zinc bromide with the zinc borate. This results in a rapid formation of a carbon layer with a certain strength during combustion, preventing the formation of holes due to melt collapse during combustion.

[0027] (2) The fiber-free flame-retardant polyamide composition described in this application can achieve a flame retardant level of 5VA, which improves the flame retardant performance without affecting its gloss and mirror effect. Detailed Implementation

[0028] To better illustrate the purpose, technical solution, and advantages of this application, the following will further describe this application in conjunction with specific embodiments, but the scope of protection and implementation methods of this application are not limited thereto.

[0029] Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0030] Examples 1-8

[0031] Examples of the non-fiber flame-retardant polyamide composition and its preparation method described in this application are shown in Table 1.

[0032] The preparation method of the fiber-free flame-retardant polyamide composition includes the following steps:

[0033] The components are mixed and added to a twin-screw extruder. After granulation and cooling, a fiber-free flame-retardant polyamide composition is obtained.

[0034] The process parameters of the twin-screw extruder are as follows:

[0035] Extrusion temperature: Zone 1 190℃, Zone 2 260℃, Zone 3 270℃, Zone 4 275℃, Zone 5 275℃, Zone 6 275℃, Zone 7 270℃, Zone 8 270℃, Zone 9 270℃; Screw speed is 300-500 rpm.

[0036] Comparative Examples 1-12

[0037] The only difference between the comparative examples and the embodiments is the type and ratio of components, as shown in Table 2.

[0038] In the components described in each embodiment and comparative example:

[0039] The polyamide resin 1, PA66, has a viscosity of 2.1 and was purchased from Invista, USA, model PA66U2501.

[0040] The polyamide resin 2, PA66, has a viscosity of 2.4 and was purchased from Invista, USA, model PA66U3600 NC01 SS.

[0041] The polyamide resin 3: PA66, with a viscosity of 2.7, was purchased from Invista, USA, and its model number is PA66U4800 NC01 SS.

[0042] The polyamide resin 4: PA6, with a viscosity of 2.5, was purchased from Jiangsu Hongsheng New Material Co., Ltd., and its model is BE3250.

[0043] The brominated flame retardant 1 is brominated polystyrene, purchased from Albemarle Corporation, USA, model BPS 7010;

[0044] The brominated flame retardant 2 is a brominated epoxy, CXB-2000H, purchased from Woo Jin Copolymer Co., Ltd.;

[0045] The brominated flame retardant 3 comprises brominated polystyrene and brominated epoxy in a weight ratio of 3:1.

[0046] The brominated flame retardant 4 comprises brominated polystyrene and brominated epoxy in a weight ratio of 3:2.

[0047] The zinc borate was purchased from Jinan Taixing Fine Chemical Co., Ltd., and its model number is HT-207.

[0048] The antimony white substance was purchased from Changde Chenzhou Antimony Products Co., Ltd., and its model number is S-05N.

[0049] The glass fiber was purchased from China Jushi Co., Ltd., ECS10-03-568H.

[0050] The zinc bromide in question is commercially available.

[0051] The antioxidant is antioxidant 1098, purchased from BASF.

[0052] The zinc chloride in question is commercially available.

[0053] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this application are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0054] Table 1

[0055] Table 2

[0056] To verify the performance of the fiberless flame-retardant polyamide compositions described in this application, the fiberless flame-retardant polyamide compositions prepared in the various examples and comparative examples were injection molded into specimens for testing the following properties.

[0057] Performance testing methods:

[0058] 1. Combustion performance test: The test is conducted in accordance with the UL 945VA test standard, and the test strip thickness is 2.0mm.

[0059] 2. Tensile strength: Tested according to ISO 527-2-2012 standard.

[0060] 3. Gloss is tested according to ASTM D523, with a geometrical reflection angle of 60 degrees.

[0061] 4. Mirror effect test: Visually inspect and classify the mirror clarity into the following five levels:

[0062] Poor: Almost no mirror-like imaging effect;

[0063] Poor: Barely achieves an imaging effect, but the quality is extremely poor;

[0064] Normal: It has basic imaging effects and can present a general outline;

[0065] Good: The imaging effect is good, and it can completely map the overall effect except for some details;

[0066] Clarity: It can fully map all the details of an object.

[0067] The performance parameters obtained from the above tests are shown in Tables 3 and 4.

[0068] Table 3

[0069] Table 4

[0070] As can be seen from Examples 1-3, by controlling the viscosity of the polyamide resin within the range of 2.4-2.7, the polyamide composition can achieve a flame retardant rating of 5VA, improving flame retardant performance without affecting its gloss and mirror effect.

[0071] Comparing Comparative Example 1 with Example 1, it can be seen that the viscosity of the polyamide resin in Comparative Example 1 is too low, and the polyamide composition cannot pass the 5VA square plate test, indicating that the viscosity of the polyamide resin will have a certain impact on the flame retardant properties of the composition.

[0072] Comparing Comparative Examples 2-4 and 7 with Example 1, it can be seen that Comparative Example 2 did not contain antimony white, Comparative Example 3 did not contain zinc borate, Comparative Example 4 did not contain zinc bromide, and Comparative Example 7 used zinc chloride instead of zinc bromide. None of the polyamide compositions passed the 5VA square plate test. This indicates that only by adding zinc borate to the antimony bromide flame retardant system can the flame retardant performance of the polyamide composition be significantly improved in this application, in conjunction with the complexation effect produced by zinc bromide.

[0073] Comparing Comparative Examples 5 and 6 with Example 1, it can be seen that the zinc bromide content in Comparative Example 5 is too low, and the polyamide composition cannot pass the 5VA square plate test; the zinc bromide content in Comparative Example 6 is too high. Although the polyamide composition can pass the 5VA square plate test, the mirror effect of the polyamide composition is not as good as that of Example 1. This shows that by controlling the zinc bromide content, this application can not only enable the polyamide composition to reach the 5VA flame retardant level, but also improve the mirror effect of the polyamide composition.

[0074] Comparing Comparative Example 8 with Example 1, it can be seen that the addition of glass fiber in Comparative Example 8 resulted in the polyamide composition passing the 5VA square plate test and exhibiting improved mechanical properties, but significantly reduced mirror effect and gloss.

[0075] According to the comparison between Comparative Examples 9-10 and Example 1, the content of brominated flame retardant in Comparative Example 9 was too low, and the polyamide composition could not pass the 5VA square plate test; the content of brominated flame retardant in Comparative Example 10 was too high, and the mechanical properties and mirror effect of the polyamide composition were reduced.

[0076] According to the comparison between Comparative Examples 11-12 and Example 1, the content of antimony white in Comparative Example 11 is too low, and the polyamide composition cannot pass the 5VA square plate test; the content of antimony white in Comparative Example 12 is too high, and the mechanical properties, mirror effect and clarity of the polyamide composition will be reduced.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application 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 application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A fiber-free flame-retardant polyamide composition, characterized in that, Includes the following components in parts by weight: The polyamide resin comprises 55-81 parts; a brominated flame retardant comprises 19-42 parts; zinc borate comprises 4-12 parts; antimony white comprises 1-12 parts; zinc bromide comprises 0.1-0.6 parts; and the viscosity of the polyamide resin is 2.4-2.

7.

2. The fiber-free flame-retardant polyamide composition according to claim 1, characterized in that, The polyamide resin includes at least one of PA6, PA66, and PA6T / 66.

3. The fiber-free flame-retardant polyamide composition according to claim 1 or 2, characterized in that, The brominated flame retardant includes at least one of brominated polystyrene, brominated epoxy, and decabromodiphenyl ethane.

4. The fiber-free flame-retardant polyamide composition according to claim 3, characterized in that, The brominated flame retardant includes brominated polystyrene and brominated epoxy, and the weight ratio of the brominated polystyrene to the brominated epoxy is greater than 2:

1.

5. The non-fiber flame-retardant polyamide composition according to any one of claims 1-4, characterized in that, The fiber-free flame-retardant polyamide composition comprises the following components in parts by weight: 56-80 parts polyamide resin; 20-40 parts brominated flame retardant; 5-10 parts zinc borate; 2-10 parts antimony white; 0.1-0.5 parts zinc bromide.

6. The fiber-free flame-retardant polyamide composition according to any one of claims 1-5, characterized in that, The fiberless flame-retardant polyamide composition further includes 0.1-0.5 parts of antioxidant.

7. The fiber-free flame-retardant polyamide composition according to claim 6, characterized in that, The antioxidants include hindered phenolic antioxidants or hindered amine antioxidants.

8. The method for preparing the fiberless flame-retardant polyamide composition according to any one of claims 1-7, characterized in that, Includes the following steps: The components are mixed and added to a twin-screw extruder. After granulation and cooling, a fiber-free flame-retardant polyamide composition is obtained.

9. The method for preparing the fiber-free flame-retardant polyamide composition according to claim 8, characterized in that, The temperature of the twin-screw extruder is 190-275℃, and the screw speed is 300-500 rpm.

10. The application of the fiber-free flame-retardant polyamide composition according to any one of claims 1-7 in electronics, electrical engineering, and new energy.

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