Low-fouling halogen-free flame-retardant nylon material and preparation method and application thereof

Abstract

The application discloses a kind of low mould scale halogen-free flame-retardant nylon materials and preparation method and application, belong to high polymer material technical field.The low mould scale halogen-free flame-retardant nylon material includes the following weight parts of component: polyamide resin 50~70 parts, halogen-free flame retardant 12~20 parts, glass fiber 10~32 parts, flame-retardant stabilizer 0.1~5 parts.The application introduces flame-retardant stabilizer in halogen-free flame-retardant nylon material, the introduced flame-retardant stabilizer has good compatibility with polyamide resin and halogen-free flame retardant, in the processing, flame-retardant stabilizer can protect halogen-free flame retardant to a certain extent, reduce the decomposition of halogen-free flame retardant, reduce the small molecule substance of system precipitation in injection molding process, to reduce the generation of mould scale, reduce washing mould frequency, it has important significance to continuous stable injection molding production electronic and electrical parts.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a low-mold-scale halogen-free flame-retardant nylon material and a preparation method and application thereof. BACKGROUND

[0002] Polyamide (PA), also known as nylon, has a wide range of applications in the electronic and electrical fields due to its excellent mechanical properties, solvent resistance and electrical properties. With the promulgation of the EU's ROHS directive on limiting and banning toxic substances and the WEEK directive on handling waste electronic equipment, the trend of halogen-free in the electronic and electrical industry is becoming increasingly clear.

[0003] Commonly used phosphorus-based flame retardants for halogen-free flame-retardant nylon include melamine cyanurate, hypophosphite, red phosphorus, etc. On the one hand, the flame retardant is prone to decomposition to produce small molecules during processing, and on the other hand, the acidic substances produced by the decomposition of the flame retardant are prone to cause degradation of the nylon at high temperatures, forming oligomers and small molecules. As the injection molding process proceeds, a large amount of small molecule substances are deposited on the surface of the mold, forming mold scale, which easily blocks the exhaust hole, leading to poor replication, end gas burning, and other consequences. Frequent cleaning of the mold will have a negative impact on the continuous and stable production of the factory, product quality stability, and production efficiency.

[0004] Currently, the existing conventional nylon material formulations and preparation processes cannot solve the problem of reducing mold scale while achieving halogen-free flame retardation. For example, the patent for invention with publication number CN112029277A discloses a halogen-free flame-retardant reinforced high-temperature nylon material and a preparation method thereof, which uses hydrotalcite and sodium polyacrylate as acid absorbents to absorb part of the small molecule volatile substances produced by decomposition, capture free acid, and reduce the generation of mold scale, but the overall fluidity of the system is significantly reduced, and the warpage is increased. The patent for invention with publication number CN111171380A discloses a coated flame retardant and a preparation method thereof, which uses a metal salt of ethylene-acrylic acid copolymer as a coating resin to coat the phosphorus-based metal salt flame retardant, which can improve the thermal decomposition of the flame-retardant component during heating and improve the toughness of the material, but this method adds an additional process of preparing the flame retardant coating master batch, and only the flame-retardant performance and mechanical properties of the system are disclosed. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a low-mold-scale halogen-free flame-retardant nylon material and a preparation method and application thereof. The present application introduces a flame-retardant stabilizer into the halogen-free flame-retardant nylon material, which plays a certain protective role on the halogen-free flame retardant, thereby reducing the thermal decomposition and mutual reaction of the halogen-free flame retardant in the nylon material system during processing, reducing the precipitation of small molecule substances, and further reducing the generation of mold scale.

[0006] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0007] In a first aspect, the present application provides a low-mold low-halogen flame-retardant nylon material, comprising the following components by weight: polyamide resin 50-70 parts, halogen-free flame retardant 12-20 parts, glass fiber 10-32 parts, flame-retardant stabilizer 0.1-5 parts; the flame-retardant stabilizer comprises at least one of a binary copolymer and a ternary copolymer; the binary copolymer is at least one of ethylene-methyl acrylic acid copolymer, ethylene-methyl acrylate copolymer, maleic anhydride grafted ethylene-octene copolymer, and ethylene-acrylic acid copolymer; the ternary copolymer is at least one of ethylene-methyl acrylic acid-acrylate copolymer, maleic anhydride grafted ethylene-propylene-non-conjugated diene copolymer, and ethylene-methyl acrylate-glycidyl methacrylate.

[0008] The present application uses at least one of a binary copolymer and a ternary copolymer as a flame-retardant stabilizer, which not only has good compatibility with polyamide resin and halogen-free flame retardant, but also protects the halogen-free flame retardant, reduces thermal decomposition and mutual reaction of the halogen-free flame retardant in the nylon material system during processing, especially reduces the decomposition of secondary phosphate, and further inhibits the precipitation of small molecule substances in the nylon material system, thereby reducing the generation of mold dirt.

[0009] As a preferred embodiment of the present application, the weight percentage content of the polyamide resin in the low-mold low-halogen flame-retardant nylon material is 40-60%, and further preferably 50-60%.

[0010] As a preferred embodiment of the present application, the flame-retardant stabilizer comprises a binary copolymer and a ternary copolymer, and the weight ratio of the binary copolymer and the ternary copolymer is (0.3-3):1. It has been found through research that when the compounding ratio of the binary copolymer and the ternary copolymer meets this condition, the halogen-free flame retardant can be better protected, and the amount of mold dirt generated can be greatly reduced.

[0011] As a preferred embodiment of the present application, the halogen-free flame retardant comprises organic secondary phosphate, melamine derivative, and zinc borate, and the weight ratio of the organic secondary phosphate, the melamine derivative, and the zinc borate is organic secondary phosphate: melamine derivative: zinc borate = (6-7):(0.5-1.5):1.

[0012] The organic secondary phosphate is aluminum diethylphosphinate, and the melamine derivative is melamine polyphosphate.

[0013] As a preferred embodiment of the present application, the polyamide resin comprises at least one of polycaprolactam (PA6), polyhexamethylene adipamide (PA66), polyhexamethylene adipate (PA56), hexamethylene adipamide-terephthaloyl hexamethylene copolyamide (PA66 / 6T), polydecamethylene lauryl (PA1012).

[0014] Further, the polyamide resin comprises at least one of polycaprolactam and polyhexamethylene adipate, and polyhexamethylene adipamide; the weight percentage of the polyhexamethylene adipamide in the polyamide resin is not less than 70%. It is found through research that the present application uses at least one of polycaprolactam and polyhexamethylene adipate to compound with polyhexamethylene adipamide (PA66), which can effectively improve the flowability of the nylon material system in the processing process and reduce the decomposition of the halogen-free flame retardant.

[0015] As a preferred embodiment of the present application, the glass fiber is alkali-free short-cut glass fiber.

[0016] As a preferred embodiment of the present application, the lubricant comprises at least one of silicone, polyethylene wax, molybdenum ester and pentaerythritol.

[0017] As a preferred embodiment of the present application, the antioxidant comprises at least one of hindered phenolic antioxidant, hindered amine antioxidant, thioester antioxidant and phosphite antioxidant.

[0018] As a preferred embodiment of the present application, the low-mold-scale halogen-free flame-retardant nylon material comprises the following components in the weight parts: polyamide resin 55-65 parts, halogen-free flame retardant 16-18 parts, glass fiber 20-26 parts, lubricant 0.2-0.6 parts, antioxidant 0.2-1 parts, flame-retardant stabilizer 0.5-3 parts. It is found through research that when the weight parts of each component meet the above conditions, the stability of the material system in the processing process is good and the mold scale produced is less.

[0019] In the second aspect, the present application provides a preparation method of the low-mold-scale halogen-free flame-retardant nylon material according to the first aspect, comprising the following steps:

[0020] After mixing the components in proportion, extruding and granulating to obtain the low-mold-scale halogen-free flame-retardant nylon material.

[0021] As a preferred embodiment of the present application, the mixing step specifically comprises: mixing the components except the glass fiber in proportion in the high-speed mixer for 1-3 min, and adding the glass fiber into the high-speed mixer from the side feeding port during the mixing process.

[0022] As a preferred embodiment of the present application, the length-diameter ratio of the extruder is (36-48):1, the screw rotation speed is 300-500 rpm, and the extrusion temperature is 230-270 DEG C during the extrusion granulation.

[0023] In a third aspect, the present application provides an application of the low-mold-release halogen-free flame-retardant nylon material in the preparation of electronic and electrical components.

[0024] The electronic and electrical components can be new energy automobile high-voltage connectors, new energy battery cover plates, end plates or energy storage connectors.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] (1) The present application introduces a flame-retardant stabilizer into the halogen-free flame-retardant nylon material, and the introduced flame-retardant stabilizer has good compatibility with the polyamide resin and the halogen-free flame retardant. During the processing, the flame-retardant stabilizer can protect the halogen-free flame retardant to some extent, reduce the decomposition of the halogen-free flame retardant, reduce the acidity of the material system during the processing, reduce the small molecular substances precipitated from the system during the injection molding, and thus reduce the generation of mold release;

[0027] (2) The present application does not need to prepare the halogen-free flame retardant into a flame retardant master batch in advance, and the overall process is simple and practical, which is conducive to reducing the mold release of the material during the injection molding, reducing the mold cleaning frequency, and having important significance for the continuous and stable injection molding of electronic and electrical components. BRIEF DESCRIPTION OF DRAWINGS

[0028] Fig. 1 The distribution photo of the mold release on the metal sheet after the injection molding of the nylon material obtained in Example 3 for 200 molds;

[0029] Fig. 2 The distribution photo of the mold release on the metal sheet after the injection molding of the nylon material obtained in Comparative Example 2 for 200 molds. DETAILED DESCRIPTION

[0030] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples.

[0031] The materials used in the examples and comparative examples are as follows:

[0032] Polyamide Resin 1: Polyhexamethylene adipamide (PA66);

[0033] Polyamide Resin 2: Polycaprolactam (PA6);

[0034] Polyamide Resin 3: Polyamino adipate (PA56), Kaisai Biology, PA56 Ecopent-1251;

[0035] Polyamide resin 4: Hexamethylene adipamide-terephthalamide copolyamide (PA66 / 6T), Invista, NPD-652;

[0036] Polyamide resin 5: Poly(dodecanedioic acid decanediamide) (PA1012), Shanghai Yinggu Chemical Industry, PA1012RV26;

[0037] Flame retardant stabilizer 1: Ethylene-methyl acrylate copolymer, DuPont-Teijin, surlyn resin 9320;

[0038] Flame retardant stabilizer 2: Ethylene-methacrylic acid-acrylate copolymer, DuPont-Teijin, Nucrel AN4228C;

[0039] Flame retardant stabilizer 3: Ethylene-methacrylic acid copolymer, DuPont-Teijin, surlyn 9910;

[0040] Flame retardant stabilizer 4: Maleic anhydride grafted ethylene-octene copolymer, grafting rate of maleic anhydride is 0.4%, DuPont-Teijin, FUSABOND N493;

[0041] Flame retardant stabilizer 5: Ethylene-acrylic acid copolymer, DuPont-Teijin, Nucrel 3990L;

[0042] Flame retardant stabilizer 6: Maleic anhydride grafted ethylene-propylene-non-conjugated diene copolymer, grafting rate of maleic anhydride is 0.9%, DuPont-Teijin, FUSABOND N416;

[0043] Flame retardant stabilizer 7: Ethylene-methyl acrylate-glycidyl methacrylate copolymer, Arkema, LOTADER AX8900;

[0044] Flame retardant stabilizer 8: Maleic anhydride grafted polyethylene, grafting rate of maleic anhydride is 0.8%, DuPont-Teijin, FUSABOND E226;

[0045] Organic phosphite: Aluminum diethylphosphite, Clariant, OP 1230;

[0046] Melamine derivative: Melamine polyphosphate, Budenheim, BUDIT 3141;

[0047] Glass fiber: Alkali-free chopped glass fiber, Giant Stone Group, ECS10-03-568H;

[0048] Lubricant: TR044W;

[0049] Antioxidant 1: IRGANOX 1098 hindered phenolic antioxidant;

[0050] Antioxidant 2: PEP-36 phosphite antioxidant;

[0051] Halogen-free flame retardant 1 is a compound of organic phosphite, melamine derivative and zinc borate with a weight ratio of organic phosphite: melamine derivative: zinc borate = 6.5: 1: 1;

[0052] Halogen-free flame retardant 2 is a compound of organic phosphite, melamine derivative and zinc borate with a weight ratio of organic phosphite: melamine derivative: zinc borate = 6: 1.5: 1;

[0053] Halogen-free flame retardant 3 is a compound of organic phosphite, melamine derivative and zinc borate with a weight ratio of organic phosphite: melamine derivative: zinc borate = 7: 0.5: 1;

[0054] The materials used in the embodiments and comparative examples of the present application are commercially available unless otherwise specified, and the raw materials used in each parallel experiment are the same.

[0055] Example 1

[0056] In one embodiment of the low-mold low-halogen flame-retardant nylon material described in the present application, the components of the low-mold low-halogen flame-retardant nylon material described in this embodiment are shown in Table 1, and the preparation method is as follows:

[0057] Add all components except glass fiber into a high-speed mixer and mix for 1-3 min; add the mixed material into a twin-screw extruder, add glass fiber from the side feeding port, extrude and granulate to obtain the low-mold low-halogen flame-retardant nylon material, the length-diameter ratio of the twin-screw extruder is (36-48): 1, the screw rotation speed is 300-500 rpm, and the extrusion temperature is 230-270℃.

[0058] Examples 2-25 and Comparative Examples 1-4

[0059] The formulations of Examples 2-25 and Comparative Examples 1-4 are shown in Tables 1-3, and the preparation method is the same as that of Example 1.

[0060] Table 1

[0061]

[0062] Table 2

[0063]

[0064] Table 3

[0065]

[0066]

[0067] The nylon materials obtained in the above examples and comparative examples were tested, and the test results are shown in Table 4, and the test methods are as follows:

[0068] (1) The nylon materials obtained in each example and comparative example were dried in an oven at 120℃ for 4h, and the following method was used for injection molding and evaluation of mold fouling: a special mold for mold fouling was used, which was provided with a detachable square metal sheet at the end of the injection molding, which was used to collect the solid or liquid mold fouling generated by the material during injection molding. Before starting injection molding, the metal sheet was removed and cleaned, and weighed as M0; after 200 continuous injection moldings, the metal sheet was removed again, photographed and weighed, recorded as M1, and the mold fouling weight was M=M1-M0;

[0069] (2) Flame retardant performance test: the nylon materials obtained in each example and comparative example were respectively injection molded into 1.6mm standard UL94 flame retardant sample, and the flame retardant performance was evaluated: 5 samples were tested in each group, and the flame retardant grade was determined according to UL94 standard;

[0070] (3) Flowability test: the melt flow rate of the material was tested according to the standard of ISO1133:2022, and the test conditions were 280℃ and 2.16kg.

[0071] Table 4

[0072]

[0073]

[0074] The flame retardant stabilizer of at least one of the specific binary copolymer and ternary copolymer in the material system of the embodiment of the application not only has good compatibility with other components of the system, so that the material has good flowability, the melt flow rate under the load of 280℃ and 2.15kg is not less than 13g / 10min; but also can fully protect the halogen-free flame retardant, inhibit the thermal decomposition or mutual reaction of the halogen-free flame retardant, reduce the acidity of the material system, inhibit the precipitation of small molecular substances in the material system, and further reduce the generation of mold fouling, the weight of the mold fouling generated after 200 continuous injection moldings is ≤5.4mg, and the flame retardant grade of the material system reaches V-0 level.

[0075] As can be seen from Examples 1-4 and Examples 14-16, under the condition that the weight parts of other components remain unchanged, the use of any one of polycaprolactam (PA6), poly(pentamethylene adipate) (PA56) and poly(hexamethylene adipate) (PA66) in combination with poly(hexamethylene adipate) (PA66) can effectively improve the flowability of the nylon material system, reduce the decomposition of the halogen-free flame retardant, thereby reducing the generation of mold fouling, and the weight of the mold fouling generated after 200 continuous injection moldings is <3.5g.

[0076] From the examples 3 and 5-9, compared with the examples 5-6, the binary copolymer and the ternary copolymer are compounded as the flame-retardant stabilizer in proper proportion in the examples 3 and 7-9, which can better protect the halogen-free flame retardant, ensure the nylon material system to have good fluidity, and greatly reduce the amount of mold dirt, so that the weight of the mold dirt produced after 200 continuous injection molding is ≤3.5g.

[0077] From the examples 3 and 5-9, compared with the examples 5-6, the binary copolymer and the ternary copolymer are compounded as the flame-retardant stabilizer in proper proportion in the examples 3 and 7-9, which can better protect the halogen-free flame retardant, ensure the nylon material system to have good fluidity, and greatly reduce the amount of mold dirt, so that the weight of the mold dirt produced after 200 continuous injection molding is ≤3.5g. Figs. 1-2 From the examples 3 and 5-9, compared with the examples 5-6, the binary copolymer and the ternary copolymer are compounded as the flame-retardant stabilizer in proper proportion in the examples 3 and 7-9, which can better protect the halogen-free flame retardant, ensure the nylon material system to have good fluidity, and greatly reduce the amount of mold dirt, so that the weight of the mold dirt produced after 200 continuous injection molding is ≤3.5g.

[0078] From the examples 3, 17-23 and the comparative example 4, it can be seen that the binary copolymer and the ternary copolymer are compounded as the flame-retardant stabilizer, which can better protect the halogen-free flame retardant, reduce the amount of mold dirt, and improve the flame-retardant performance of the material system.

[0079] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, but not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the essence and scope of the present application.

Claims

1. A low-modulus, halogen-free, flame-retardant nylon material, characterized in that, The product comprises the following components in parts by weight: 50-70 parts polyamide resin, 12-20 parts halogen-free flame retardant, 10-32 parts glass fiber, and 0.1-5 parts flame retardant stabilizer; wherein the flame retardant stabilizer is composed of a binary copolymer and a terpolymer; wherein the binary copolymer is at least one of ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, maleic anhydride-grafted ethylene-octene copolymer, and ethylene-acrylic acid copolymer; wherein the terpolymer is at least one of ethylene-methacrylic acid-acrylate copolymer, maleic anhydride-grafted ethylene-propylene-non-conjugated diene copolymer, and ethylene-methyl acrylate-glycidyl methacrylate, and the weight ratio of the binary copolymer to the terpolymer is (0.3-3):1; The halogen-free flame retardant is an organic hypophosphite, a melamine derivative, and zinc borate; The weight ratio of the organic hypophosphite, melamine derivative, and zinc borate is organic hypophosphite: melamine derivative: zinc borate = (6~7): (0.5~1.5):

1.

2. The low-modulus, halogen-free flame-retardant nylon material as described in claim 1, characterized in that, The polyamide resin includes at least one of polycaprolactam, polyhexamethylene adipamide, polypentyl adipate diamine, hexamethylene adipamide-hexamethylene terephthalamide copolyamide, and polydecanoyl diamine.

3. The low-modulus, halogen-free flame-retardant nylon material as described in claim 2, characterized in that, The polyamide resin includes at least one of polycaprolactam and polypentyl adipate, and polyhexamethylene adipate; the polyhexamethylene adipate in the polyamide resin is not less than 70% by weight.

4. The low-modulus, halogen-free flame-retardant nylon material as described in claim 1, characterized in that, It also contains the following components in parts by weight: 0.1 to 2 parts lubricant and 0.1 to 3 parts antioxidant.

5. The low-modulus, halogen-free flame-retardant nylon material as described in claim 4, characterized in that, It contains the following components in parts by weight: 55-65 parts polyamide resin, 16-18 parts halogen-free flame retardant, 20-26 parts glass fiber, 0.2-0.6 parts lubricant, 0.2-1 part antioxidant, and 0.5-3 parts flame retardant stabilizer.

6. A method for preparing a low-modulus, halogen-free flame-retardant nylon material as described in any one of claims 1 to 5, characterized in that, Includes the following steps: After mixing the components in proportion, the mixture is extruded and granulated to obtain a low-modulus, halogen-free flame-retardant nylon material.

7. The application of a low-fouling, halogen-free flame-retardant nylon material as described in any one of claims 1 to 5 in the manufacture of electronic and electrical components.

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