Halogen-free flame-retardant long-chain nylon composite material and preparation method thereof

Abstract

The application discloses a halogen-free flame-retardant long-chain nylon composite material and a preparation method thereof, and belongs to the technical field of nylon flame retardation, and overcomes the defects that high flame-retardant performance and low smoke density of long-chain nylon resin are difficult to be considered in the prior art.The halogen-free flame-retardant long-chain nylon composite material is prepared from the following raw materials in parts by mass: long-chain nylon resin: 65-92 parts, MCA flame retardant: 5-25 parts, the MCA flame retardant being melamine cyanurate, non-benzene ring phosphorus-containing flame retardant: 1-10 parts, and auxiliary agent: 0-5 parts.The halogen-free flame-retardant long-chain nylon composite material maintains a low smoke density by means of the synergistic effect of the non-benzene ring phosphorus-containing flame retardant and the MCA flame retardant to improve the flame-retardant performance.

Description

Technical Field

[0001] This invention belongs to the field of nylon flame retardant technology, specifically relating to a halogen-free flame retardant long-chain nylon composite material and its preparation method. Background Technology

[0002] Polyamide materials possess excellent comprehensive properties, including superior mechanical properties, wear resistance, heat resistance, and chemical corrosion resistance, making them widely used in transportation, electronics, machinery manufacturing, power tools, and construction. Among polyamide materials, PA12 exhibits particularly outstanding toughness, maintaining good toughness even at -50℃, and is widely used in the automotive and rail transportation sectors.

[0003] In rail transit and electronic applications, certain fire resistance properties are typically required. Halogenated flame retardants have limitations in application due to their high smoke emission, low CTI performance, and high density; red phosphorus also has limitations in application to some extent due to its dark color and post-corrosion problems; halogen-free non-phosphorus flame retardants, especially melamine cyanurate (MCA) flame retardants, are widely used in nylon flame retardant modification due to their low price, low smoke emission, and low toxicity.

[0004] Adding only 8-10 wt% MCA is sufficient to achieve a UL94 V-0 flame retardant rating of 0.8 mm in unreinforced PA66 systems. However, adding MCA alone to PA12 results in drip ignition during flame retardant testing, failing to reach the UL94 V-0 rating. Furthermore, the synergistic effect of MCA with phosphorus-containing flame retardants in existing technologies leads to an increase in the smoke density of the composite material. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art in which it is difficult to achieve both high flame retardancy and low smoke density of long-chain nylon resin, thereby providing a halogen-free flame retardant long-chain nylon composite material and its preparation method.

[0006] To this end, the present invention provides the following technical solution.

[0007] In a first aspect, the present invention provides a halogen-free flame-retardant long-chain nylon composite material, the raw material composition by mass parts being:

[0008] Long-chain nylon resin: 65–92 parts,

[0009] MCA flame retardant: 5-25 parts, wherein the MCA flame retardant is melamine cyanurate;

[0010] Benzene ring-free phosphorus-containing flame retardant: 1-10 parts,

[0011] Additives: 0-5 parts.

[0012] Long-chain nylon resin, with a melting peak temperature ≥160℃ as tested according to GB / T 19466.3-2004 standard.

[0013] Long-chain nylon resin is nylon in which the main chain repeating unit of the nylon molecule contains amide groups and the methylene length between two amide groups is greater than 10.

[0014] Secondly, this invention provides another halogen-free flame-retardant long-chain nylon composite material, the raw material composition by mass parts being:

[0015] Long-chain nylon resin: 65–92 parts,

[0016] Long-chain nylon elastomer: 1-10 parts

[0017] MCA flame retardant: 5-25 parts, wherein the MCA flame retardant is melamine cyanurate.

[0018] Benzene ring-free phosphorus-containing flame retardant: 1-10 parts,

[0019] Additives: 0-5 parts.

[0020] Long-chain nylon elastomers are used as toughening agents.

[0021] In one possible implementation, the long-chain nylon resin is selected from at least one of PA12, PA11, PA1012, PA1212, PA1010, PA410, PA412, PA510, PA512, PA610, and PA612.

[0022] Preferably, at least one of PA12, PA11, and PA1012 is selected.

[0023] In one possible implementation, the long-chain nylon elastomer is selected from at least one of PA12 elastomer, PA1012 elastomer, and PA11 elastomer;

[0024] Optionally, the long-chain nylon elastomer is 2-8 parts, preferably 3-6 parts.

[0025] In one possible implementation, the average particle size D50 of the MCA flame retardant is 0.1 μm to 25 μm, preferably 0.2 to 10 μm, and more preferably 0.3 to 3 μm.

[0026] In one possible implementation, the benzene-free phosphorus-containing flame retardant is a phosphate ester that does not contain benzene rings.

[0027] In one possible embodiment, the benzene ring-free phosphate ester is selected from 3,9-dimethyl-3,9-dioxo-2,4,8,10-tetraoxa-3,9-diphosphadispiro[5,5]undecane, 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane, and bis(1-oxo-4-methylene-2,6,7-trioxabicyclo[2,2,2]octane) phosphate (2,4,6-triamino-1,3,5-triazine). At least one of the following: ) salt, tris(1-oxo-4-methylene-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane) phosphate; methylphosphonic acid (5-ethyl-2-methyl-2-oxo-1,3,2-dioxophosphacyclohexane-5-yl) methyl methyl ester, bis[(5-ethyl-2-methyl-1,3,2-dioxophosphacyclohexane-5-yl) methyl] methylphosphonate P, P'-dioxide, and (2-amino-2-oxoethyl) diethyl phosphate.

[0028] In one possible implementation, the additives include one or more of antioxidants, lubricants, nucleating agents, plasticizers, and color masterbatches.

[0029] In one possible implementation, the MCA flame retardant is 5 to 20 parts, preferably 6 to 12 parts;

[0030] In one possible implementation, the amount of the benzene ring-free phosphorus-containing flame retardant is 1 to 8 parts, more preferably 2 to 6 parts.

[0031] Thirdly, the present invention provides a method for preparing a halogen-free flame-retardant long-chain nylon composite material, comprising the following steps: mixing the components according to the formula and adding them to a twin-screw extruder for melt extrusion granulation to prepare a halogen-free flame-retardant long-chain nylon composite material.

[0032] The technical solution of this invention has the following advantages:

[0033] 1. The present invention relates to a halogen-free flame-retardant long-chain nylon composite material, wherein the raw material composition by mass parts is as follows: long-chain nylon resin: 65-92 parts, MCA flame retardant: 5-25 parts, wherein the MCA flame retardant is melamine cyanurate; benzene ring-free phosphorus-containing flame retardant: 1-10 parts, and additives: 0-5 parts.

[0034] This invention utilizes the synergistic effect of a benzene-ring-free phosphorus-containing flame retardant and an MCA flame retardant. The high phosphorus content results in the production of a large amount of phosphoric acid-containing substances during combustion of the composite material, absorbing a significant amount of heat and greatly reducing the combustion time. Simultaneously, it accelerates the dripping process, ensuring that the drips are completely flame-free and preventing ignition during flame retardant testing of long-chain nylon composites. This allows the halogen-free flame-retardant long-chain nylon composite material to achieve a stable 0.8mm UL94V-0 rating. The phosphorus-containing flame retardant used does not contain benzene rings in its molecular structure, maintaining a low smoke density in the halogen-free flame-retardant long-chain nylon composite material.

[0035] 2. Another halogen-free flame-retardant long-chain nylon composite material of the present invention has the following raw material composition by mass parts: long-chain nylon resin: 65-92 parts, long-chain nylon elastomer: 1-10 parts, MCA flame retardant: 5-25 parts, wherein the MCA flame retardant is melamine cyanurate, benzene ring-free phosphorus-containing flame retardant: 1-10 parts, and additives: 0-5 parts.

[0036] By using a compounded long-chain nylon elastomer as a toughening agent, the toughness is improved without affecting the flame retardant properties of the composite. This invention utilizes the synergistic effect of MCA flame retardant, benzene ring-free phosphorus-containing flame retardant, and long-chain nylon elastomer to achieve a 0.8mm UL94 V-0 rating for halogen-free flame-retardant long-chain nylon composite material, while maintaining a low smoke density and excellent toughness. Detailed Implementation

[0037] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0038] Where specific experimental steps or conditions are not specified in the examples, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0039] Source of raw materials

[0040] PA-1#: PA12, Wanamid L3000, Wanhua Chemical.

[0041] PA-2#: PA1012, Type II, Shandong Dongchen Ruisen New Material Technology Co., Ltd.

[0042] Toughening Agent-1#: Long-chain nylon elastomer, 3533, Arkema, France.

[0043] Toughening Agent-2#: Long-chain nylon elastomer, TPA12-63, Shandong Dongchen Ruisen New Material Technology Co., Ltd.

[0044] Toughening Agent-3#: Conventional nylon toughening agent, Fusabond N493, Dow Chemical, USA.

[0045] Flame retardant A: MCA, XS-MC-151, Zhejiang Xusen Flame Retardant Co., Ltd., D50 is 1.5μm.

[0046] Flame retardant B: 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane, commercially available.

[0047] Flame retardant C: Tris(1-oxo-4-methylene-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane) phosphate, commercially available.

[0048] Flame retardant D: Resorcinol bis(diphenyl phosphate) (RDP), commercially available.

[0049] Antioxidant: A 1:1 mixture of antioxidants 1098 and 168 by mass, commercially available.

[0050] Lubricant: Calcium stearate, commercially available.

[0051] Test methods

[0052] The performance of the halogen-free flame-retardant long-chain nylon composite materials prepared in the following examples and comparative examples was tested using the following methods:

[0053] (1) Tensile strength: Tested in accordance with GB / T1040.2-2022 standard;

[0054] (2) Tensile fracture strain: Tested in accordance with GB / T1040.2-2022 standard;

[0055] (3) Flame retardant performance: 0.8mm thick standard UL94 test strips (10 strips per group) were injection molded and tested according to UL94 standard, and the flame retardant rating was recorded.

[0056] (4) Smoke density Ds(max): Tested according to ISO 5659-2:2017 standard.

[0057] Example 1

[0058] Weigh out 83.4 parts PA-1#, 10 parts flame retardant A, 6 parts flame retardant B, 0.4 parts antioxidant, and 0.2 parts lubricant according to the mass fractions. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0059] Example 2

[0060] Weigh out 82.4 parts PA-1#, 14 parts flame retardant A, 3 parts flame retardant C, 0.4 parts antioxidant, and 0.2 parts lubricant according to the mass fractions. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0061] Example 3

[0062] Weigh out 76.4 parts PA-1#, 14 parts flame retardant A, 9 parts flame retardant C, 0.4 parts antioxidant, and 0.2 parts lubricant according to the mass fractions. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0063] Example 4

[0064] Weigh out 83.4 parts PA-1#, 10 parts flame retardant A, 3 parts flame retardant B, 3 parts flame retardant C, 0.4 parts antioxidant, and 0.2 parts lubricant according to the mass fractions. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0065] Example 5

[0066] Weigh out 83.4 parts PA-2#, 10 parts flame retardant A, 3 parts flame retardant B, 3 parts flame retardant C, 0.4 parts antioxidant, and 0.2 parts lubricant according to the mass fractions. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0067] Example 6

[0068] Weigh out 77.4 parts PA-1#, 6 parts toughening agent-1#, 10 parts flame retardant A, 3 parts flame retardant B, 3 parts flame retardant C, 0.4 parts antioxidant, and 0.2 parts lubricant according to the mass fractions. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0069] Example 7

[0070] Weigh out 89.4 parts PA-1#, 7 parts flame retardant A, 2 parts flame retardant B, 1 part flame retardant C, 0.4 parts antioxidant, and 0.2 parts lubricant according to the mass fractions. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0071] Example 8

[0072] Weigh out 70.4 parts PA-1#, 20 parts flame retardant A, 9 parts flame retardant C, 0.4 parts antioxidant, and 0.2 parts lubricant according to the specified mass ratio. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0073] Example 9

[0074] Weigh out 73.4 parts PA-2#, 10 parts toughening agent-2#, 10 parts flame retardant A, 3 parts flame retardant B, 3 parts flame retardant C, 0.4 parts antioxidant, and 0.2 parts lubricant according to the specified mass ratio. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0075] Comparative Example 1

[0076] Weigh out 75.4 parts PA-1#, 24 parts flame retardant A, 0.4 parts antioxidant, and 0.2 parts lubricant according to the specified mass ratio. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0077] Comparative Example 2

[0078] Weigh out 77.4 parts PA-1#, 6 parts toughening agent-3#, 10 parts flame retardant A, 3 parts flame retardant B, 3 parts flame retardant C, 0.4 parts antioxidant, and 0.2 parts lubricant according to the specified mass ratio. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0079] Comparative Example 3

[0080] Weigh out 83.4 parts PA-1#, 16 parts flame retardant A, 0.4 parts antioxidant, and 0.2 parts lubricant according to the specified mass ratio. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0081] Comparative Example 4

[0082] Weigh out 83.4 parts PA-1#, 10 parts flame retardant A, 6 parts flame retardant D, 0.4 parts antioxidant, and 0.2 parts lubricant according to the mass fractions. Mix the above raw materials evenly and put them into a twin-screw extruder for extrusion granulation. The extrusion temperature is 230℃ and the screw speed is 350rpm.

[0083] Table 1. Formulations (parts by weight) of Examples 1-9 and Comparative Examples 1-4

[0084]

[0085]

[0086] Table 2. Test results of formulations for Examples 1-9 and Comparative Examples 1-4

[0087]

[0088] The test results of Examples 1-9 and Comparative Examples 1-4 show that by combining MCA with a phosphate flame retardant that does not contain benzene rings, the halogen-free flame-retardant long-chain nylon composite material can stably achieve a UL94 V-0 rating of 0.8 mm, and the smoke density is significantly reduced.

[0089] A comparison of Example 1 with Comparative Examples 1, 3, and 4 shows that even with a relatively large amount of MCA added, the flame-retardant performance of the halogen-free flame-retardant long-chain nylon composite material is still difficult to achieve the UL94 V-0 rating when MCA is used alone as a flame retardant. Compared to the MCA and resorcinol bis(diphenyl phosphate) compound in Comparative Example 4, the halogen-free flame-retardant long-chain nylon composite material of this application, compounded with MCA and a phosphate flame retardant without benzene rings, can stably achieve a UL94 V-0 rating of 0.8 mm, and the smoke density is significantly reduced.

[0090] As can be seen from the comparison between Example 6 and Examples 1-5 and Comparative Example 2, adding long-chain nylon elastomer as a toughening agent can improve the toughness of the material without affecting its flame retardant properties.

[0091] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A halogen-free flame-retardant long-chain nylon composite, characterized by, The raw material composition is calculated by mass fraction as follows: Long-chain nylon resin: 65-92 parts, MCA flame retardant: 5-25 parts, the MCA flame retardant is melamine cyanurate; Phosphorus-containing flame retardant without benzene ring: 1-10 parts, Auxiliary: 0-5 parts; The phosphorus-containing flame retardant without benzene ring is a phosphoric acid ester without benzene ring; the phosphoric acid ester without benzene ring is at least one selected from 3,9-dimethyl-3,9-dioxo-2,4,8,10-tetraoxa-3,9-diphosphadi- spiro [5,5] undecane, 1-oxo-4-hydroxymethyl-1-phosphorus-2,6,7-trioxa- bicyclo [2,2,2] octane, tris (1-oxo-4-methylene-1-phosphorus-2,6,7-trioxa- bicyclo [2,2,2] octane) phosphate, methyl phosphonic acid (5-ethyl-2-methyl-2- oxo-1,3,2-dioxaphosphorinanyl-5-yl) methyl methyl ester, bis [ (5-ethyl-2- methyl-1,3,2-dioxaphosphorinanyl-5-yl) methyl] methyl phosphonate P, P'- dioxide.

2. A halogen-free flame-retardant long-chain nylon composite, characterized by, The raw material composition is calculated by mass fraction as follows: Long-chain nylon resin: 65-92 parts, Long-chain nylon elastomer: 1-10 parts, MCA flame retardant: 5-25 parts, the MCA flame retardant is melamine cyanurate, Phosphorus-containing flame retardant without benzene ring: 1-10 parts, Auxiliary: 0-5 parts; The phosphorus-containing flame retardant without benzene ring is a phosphoric acid ester without benzene ring; the phosphoric acid ester without benzene ring is at least one selected from 2,4,8,10-tetraoxa-3,9-diphosphadispiro [5,5] undecane, 1-oxo-4-hydroxyl-1-phosphorus-2,6,7-trioxa- bicyclo [2.2.2] octane, tris (1-oxo-4-methylene-1-phospha-2,6,7-trioxa- bicyclo [2,2,2] Octane) phosphate, methyl phosphonic acid (5-ethyl-2-methyl-2-oxo-1,3,2-dioxaphosphorinanyl-5-yl) Methyl methyl ester, bis [ (5-ethyl-2-methyl-1,3,2-dioxaphosphorinanyl-5-yl) methyl ] methyl phosphonate P, P'-dioxide.

3. The halogen-free flame-retardant long-chain nylon composite material according to claim 1 or 2, characterized in that, The long-chain nylon resin is at least one selected from PA12, PA11, PA1012, PA1212, PA1010, PA410, PA412, PA510, PA512, PA610, PA612.

4. The halogen-free flame retardant long chain nylon composite of claim 3, wherein, The long-chain nylon resin is at least one selected from PA12, PA11, PA 1012.

5. The halogen-free, flame-retardant, long-chain nylon composite of claim 2, wherein, The long-chain nylon elastomer is at least one selected from PA12 elastomer, PA1012 elastomer, PA11 elastomer.

6. The halogen-free flame retardant long chain nylon composite of claim 2, wherein, The long-chain nylon elastomer is 2-8 parts.

7. The halogen-free flame retardant long chain nylon composite of claim 6, wherein, The long-chain nylon elastomer is 3-6 parts.

8. The halogen-free flame retardant long chain nylon composite according to claim 1 or 2, wherein, The average particle size D50 of the MCA flame retardant is 0.1-25 μm.

9. The halogen-free, flame-retardant, long-chain nylon composite of claim 8, wherein, The average particle size D50 of the MCA flame retardant is 0.2-10 μm.

10. The halogen-free, flame-retardant, long-chain nylon composite of claim 9, wherein, The average particle size D50 of the MCA flame retardant is 0,3-3 μm.

11. The halogen-free, flame-retardant, long-chain nylon composite of claim 1 or 2, wherein, The auxiliary includes one or more of antioxidants, lubricants, nucleating agents, plasticizers, color masterbatch.

12. The halogen-free, flame-retardant, long-chain nylon composite of claim 1 or 2, wherein, At least one of the following conditions is met: (1) MCA flame retardant is 5-20 parts; (2) benzene ring-free phosphorus-containing flame retardant is 1-8 parts.

13. The halogen-free, flame-retardant, long-chain nylon composite of claim 12, wherein, MCA flame retardant is 6-12 parts.

14. The halogen-free, flame-retardant, long-chain nylon composite of claim 12, wherein, Benzene ring-free phosphorus-containing flame retardant is 2-6 parts.

15. A process for the preparation of the halogen-free flame-retardant long chain nylon composite of any one of claims 1 to 14, characterized in that, The method comprises the following steps: mixing the components according to the proportion, and then adding them into a double-screw extruder to perform melt extrusion and granulation, so that a halogen-free flame-retardant long-chain nylon composite material is prepared.

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