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

Abstract

The invention discloses a halogen-free flame-retardant long-chain nylon composite material and a preparation method thereof, belongs to the technical field of nylon flame retardance, and overcomes the defect that high flame retardance and low smoke density of long-chain nylon resin are difficult to consider at the same time 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: 65 to 92 parts of long-chain nylon resin and 5 to 25 parts of MCA (melamine cyanurate) flame retardant, 1-10 parts of a benzene-ring-free phosphorus-containing flame retardant, and 0-5 parts of an auxiliary agent. According to the halogen-free flame-retardant long-chain nylon composite material, the benzene-ring-free phosphorus-containing flame retardant and the MCA flame retardant play a synergistic role, so that the flame retardant property is improved, and meanwhile, the halogen-free flame-retardant long-chain nylon composite material keeps relatively low smoke density.

Description

Technical Field

[0001] The invention belongs to the technical field of nylon flame retardancy, and in particular relates to a halogen-free flame retardant long-chain nylon composite material and a preparation method thereof. Background Art

[0002] Polyamide materials have excellent comprehensive properties such as excellent mechanical properties, wear resistance, heat resistance, and chemical corrosion resistance, and are widely used in transportation, electronic appliances, machinery manufacturing, power tools, and construction. Among polyamide materials, PA12 has particularly outstanding toughness, and it can still maintain good toughness at -50°C, and is widely used in the automotive and rail transportation fields.

[0003] In rail transit and electronic and electrical applications, certain fire resistance is usually required. Halogen flame retardants have the disadvantages of large smoke emission, low CTI performance, and high density, which limit their application; red phosphorus also has its application limited to a certain 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] Only 8-10wt% of MCA is needed to make the flame retardant performance of the non-reinforced PA66 system reach the 0.8mm UL94V-0 level. However, when MCA flame retardant is added alone to PA12, dripping and ignition will occur during the flame retardant test, and the 0.8mm UL94 V-0 level cannot be achieved. In addition, the synergistic effect of MCA and phosphorus-containing flame retardants in the prior art will increase 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 defect that it is difficult to achieve both high flame retardant performance and low smoke density of long-chain nylon resin in the prior art, thereby providing a halogen-free flame retardant long-chain nylon composite material and a preparation method thereof.

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

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

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

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

[0010] Phosphorus-containing flame retardant without benzene ring: 1-10 parts,

[0011] Additives: 0 to 5 parts.

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

[0013] Long-chain nylon resin is a nylon with an amide group in the main chain repeating unit of the nylon molecule, and the length of the methylene group between two amide groups is greater than 10.

[0014] In a second aspect, the present invention provides another halogen-free flame-retardant long-chain nylon composite material, the raw material composition is calculated by weight:

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

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

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

[0018] Phosphorus-containing flame retardant without benzene ring: 1-10 parts,

[0019] Additives: 0 to 5 parts.

[0020] Long-chain nylon elastomer is a toughening agent.

[0021] In a possible embodiment, 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] At least one of PA12, PA11 and PA1012 is preferred.

[0023] In a 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 a 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 a possible implementation, the benzene ring-free phosphorus-containing flame retardant is a phosphate ester that does not contain a benzene ring.

[0027] In a possible embodiment, the phosphate ester without a benzene ring 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, bis(1-oxo-4-methylene-2,6,7-trioxabicyclo[2,2,2]octane)phosphate (2,4,6-triamino-1,3,5-triazine ) 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-dioxaphosphorinane-5-yl) methyl methyl ester, bis[(5-ethyl-2-methyl-1,3,2-dioxaphosphorinane-5-yl)methyl]methylphosphonate P,P'-dioxide, (2-amino-2-oxoethyl) diethyl phosphate.

[0028] In a possible implementation, the auxiliary agent includes one or more of an antioxidant, a lubricant, a nucleating agent, a plasticizer, and a masterbatch.

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

[0030] In a 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] In a third aspect, 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 a ratio and adding them into 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 the present invention has the following advantages:

[0033] 1. The halogen-free flame-retardant long-chain nylon composite material of the present invention comprises the following raw materials in parts by mass: 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 auxiliary agent: 0-5 parts.

[0034] The present invention adds a benzene ring-free phosphorus-containing flame retardant to exert a synergistic effect with an MCA flame retardant; when the composite material has a high phosphorus content, a large amount of phosphoric acid-containing substances are generated when the composite material burns, absorbing a large amount of heat, greatly reducing the burning time of the material, and accelerating the melting and dripping process of the material, so that the dripping material does not contain open flames at all, avoiding the dripping and ignition phenomenon during the flame retardant test of the long-chain nylon composite material, so that the halogen-free flame-retardant long-chain nylon composite material can reach a stable 0.8mm UL94V-0 level. The molecular structure of the phosphorus-containing flame retardant used does not contain a benzene ring, so that the halogen-free flame-retardant long-chain nylon composite material maintains a low smoke density.

[0035] 2. The raw material composition of another halogen-free flame-retardant long-chain nylon composite material of the present invention is calculated by weight 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, benzene ring-free phosphorus-containing flame retardant: 1-10 parts, and auxiliary agent: 0-5 parts.

[0036] The compound long-chain nylon elastomer is used as a toughening agent to improve toughness without affecting the flame retardant performance of the composite. The present invention adopts the synergistic effect of MCA flame retardant, benzene ring-free phosphorus-containing flame retardant and long-chain nylon elastomer, so that the halogen-free flame retardant long-chain nylon composite material can reach the 0.8mm UL94 V-0 level, while maintaining a low smoke density and having excellent toughness. DETAILED DESCRIPTION

[0037] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0038] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[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] Toughener-3#: Conventional nylon toughener, Fusabond N493, Dow, USA.

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

[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 mixture of antioxidants 1098 and 168 in a mass ratio of 1:1, commercially available.

[0050] Lubricant: Calcium stearate, commercially available.

[0051] Test Method

[0052] The halogen-free flame retardant long-chain nylon composite materials prepared in the following examples and comparative examples were tested for performance using the following test 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 properties: Standard UL94 test specimens (10 pieces in a group) with a thickness of 0.8 mm were injection molded and tested according to the UL94 standard, and the flame retardant level was recorded.

[0056] (4) Smoke density Ds(max): Tested in accordance with ISO 5659-2:2017 standard.

[0057] Example 1

[0058] According to the mass proportions, 83.4 parts of PA-1#, 10 parts of flame retardant A, 6 parts of flame retardant B, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0059] Example 2

[0060] According to the mass proportions, 82.4 parts of PA-1#, 14 parts of flame retardant A, 3 parts of flame retardant C, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0061] Example 3

[0062] According to the mass proportions, 76.4 parts of PA-1#, 14 parts of flame retardant A, 9 parts of flame retardant C, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0063] Example 4

[0064] According to the mass proportions, 83.4 parts of PA-1#, 10 parts of flame retardant A, 3 parts of flame retardant B, 3 parts of flame retardant C, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0065] Example 5

[0066] According to the mass proportions, 83.4 parts of PA-2#, 10 parts of flame retardant A, 3 parts of flame retardant B, 3 parts of flame retardant C, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0067] Example 6

[0068] According to the mass proportions, 77.4 parts of PA-1#, 6 parts of toughening agent-1#, 10 parts of flame retardant A, 3 parts of flame retardant B, 3 parts of flame retardant C, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0069] Example 7

[0070] According to the mass proportions, 89.4 parts of PA-1#, 7 parts of flame retardant A, 2 parts of flame retardant B, 1 part of flame retardant C, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0071] Example 8

[0072] According to the mass proportions, 70.4 parts of PA-1#, 20 parts of flame retardant A, 9 parts of flame retardant C, 0.4 parts of antioxidant and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0073] Example 9

[0074] According to the mass proportions, 73.4 parts of PA-2#, 10 parts of toughening agent-2#, 10 parts of flame retardant A, 3 parts of flame retardant B, 3 parts of flame retardant C, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0075] Comparative Example 1

[0076] According to the mass proportions, 75.4 parts of PA-1#, 24 parts of flame retardant A, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0077] Comparative Example 2

[0078] According to the mass proportions, 77.4 parts of PA-1#, 6 parts of toughening agent-3#, 10 parts of flame retardant A, 3 parts of flame retardant B, 3 parts of flame retardant C, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0079] Comparative Example 3

[0080] According to the mass proportions, 83.4 parts of PA-1#, 16 parts of flame retardant A, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0081] Comparative Example 4

[0082] According to the mass proportions, 83.4 parts of PA-1#, 10 parts of flame retardant A, 6 parts of flame retardant D, 0.4 parts of antioxidant, and 0.2 parts of lubricant were weighed, the above raw materials were mixed evenly, and put into a twin-screw extruder for extrusion granulation. The extrusion temperature was 230°C and the screw speed was 350rpm.

[0083] Table 1 Formulas of Examples 1 to 9 and Comparative Examples 1 to 4 (parts by weight)

[0084]

[0085]

[0086] Table 2 Test results of examples 1 to 9 and comparative examples 1 to 4

[0087]

[0088] It can be seen from the test results of Examples 1-9 and Comparative Examples 1-4 that by compounding MCA and a phosphate flame retardant containing no benzene ring, the halogen-free flame retardant long-chain nylon composite material can stably reach 0.8mm UL94 V-0 level, and the smoke density is significantly reduced.

[0089] From the comparison between Example 1 and Comparative Examples 1, 3 and 4, it can be seen that if MCA is used alone as a flame retardant, even if a large amount of MCA is added, the flame retardant performance of the halogen-free flame retardant long-chain nylon composite material is still difficult to reach the UL94 V-0 level. Compared with the solution of compounding MCA and resorcinol bis(diphenyl phosphate) in Comparative Example 4, the present application compounded MCA and a phosphate flame retardant containing no benzene ring, the halogen-free flame retardant long-chain nylon composite material can stably reach the 0.8mm UL94 V-0 level, and the smoke density is significantly reduced.

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

[0091] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A halogen-free flame-retardant long-chain nylon composite material, characterized in that: The raw material composition is calculated by mass: Long chain nylon resin: 65-92 parts, MCA flame retardant: 5-25 parts, wherein the MCA flame retardant is melamine cyanurate; Phosphorus-containing flame retardant without benzene ring: 1-10 parts, Additives: 0 to 5 parts.

2. A halogen-free flame-retardant long-chain nylon composite material, characterized in that: The raw material composition is calculated by mass: 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, Additives: 0 to 5 parts.

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 selected from at least one of PA12, PA11, PA1012, PA1212, PA1010, PA410, PA412, PA510, PA512, PA610 and PA612; At least one of PA12, PA11 and PA1012 is preferred.

4. The halogen-free flame-retardant long-chain nylon composite material according to claim 2, characterized in that: The long-chain nylon elastomer is selected from at least one of PA12 elastomer, PA1012 elastomer and PA11 elastomer; Optionally, the long-chain nylon elastomer is 2-8 parts, preferably 3-6 parts.

5. The halogen-free flame-retardant long-chain nylon composite material according to claim 1 or 2, characterized in that: 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.

6. The halogen-free flame-retardant long-chain nylon composite material according to claim 1 or 2, characterized in that: The benzene ring-free phosphorus-containing flame retardant is a phosphate ester without a benzene ring.

7. The halogen-free flame-retardant long-chain nylon composite material according to claim 6, characterized in that: The phosphoric acid ester without benzene ring 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, bis(1-oxo-4-methylene-2,6,7-trioxabicyclo[2,2,2]octane)phosphate (2,4,6-triamino-1,3,5-triazine) salt, tris(1 -oxo-4-methylene-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane) phosphate; at least one of methylphosphonic acid (5-ethyl-2-methyl-2-oxo-1,3,2-dioxaphosphorinane-5-yl) methyl methyl ester, bis[(5-ethyl-2-methyl-1,3,2-dioxaphosphorinane-5-yl) methyl] methyl phosphonate P,P'-dioxide, and (2-amino-2-oxoethyl) diethyl phosphate.

8. The halogen-free flame-retardant long-chain nylon composite material according to claim 1 or 2, characterized in that: The auxiliary agent includes one or more of an antioxidant, a lubricant, a nucleating agent, a plasticizer, and a masterbatch.

9. The halogen-free flame-retardant long-chain nylon composite material according to claim 1 or 2, characterized in that: At least one of the following conditions is met: (1) 5 to 20 parts of MCA flame retardant, preferably 6 to 12 parts; (2) The amount of the benzene ring-free phosphorus-containing flame retardant is 1 to 8 parts, more preferably 2 to 6 parts.

10. A method for preparing the halogen-free flame-retardant long-chain nylon composite material according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: mixing the components according to the proportion and adding the components into a twin-screw extruder for melt extrusion granulation to prepare a halogen-free flame-retardant long-chain nylon composite material.

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