Halogen-free flame-retardant material as well as preparation method and application thereof

Abstract

The invention discloses a halogen-free flame-retardant material and a preparation method and application thereof, and the halogen-free flame-retardant material comprises the following raw materials in parts by mass: 8-30 parts of an ethylene-vinyl acetate copolymer, 3-20 parts of polyethylene resin, 3-10 parts of a grafting compatilizer, 40-70 parts of talcum powder, 0.5-7 parts of a liquid flame retardant, 0.5-7 parts of a nitrogen-based flame retardant, 0.5-7 parts of 9, 10-di-tert-butyl-4-methylphenol, 1-3 parts of a flame retardant, 1-3 parts of a flame retardant, and 1-3 parts of a flame retardant. The flame retardant comprises the following components in parts by weight: 1-8 parts of a 1, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant and 1-8 parts of an auxiliary agent. According to the invention, the ethylene-vinyl acetate copolymer and the polyethylene resin are adopted as matrix resins, and are matched with the synergistic flame retardant composed of the liquid flame retardant, the nitrogen-based flame retardant and the 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant, and the talcum powder is combined, so that the flame-retardant and flame-retardant composite material has the advantages that the flame-retardant and flame-retardant composite material is prepared; the obtained halogen-free flame-retardant material has good mechanical properties, aging resistance, flame retardance and a low-smoke effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and in particular relates to a halogen-free flame retardant material and a preparation method and application thereof. Background Art

[0002] With the upgrading of the industry, in order to further strengthen the supervision of product quality and safety, low-smoke halogen-free flame-retardant cable products need to be subject to stricter quality control. The verification contents mainly include GB / T 18380.1 single vertical burning, GB / T 18380.3 bundled burning and other performances, which also puts forward higher requirements for low-smoke halogen-free flame-retardant materials.

[0003] The low-smoke halogen-free flame retardant materials on the market are mainly aluminum hydroxide or magnesium hydroxide flame retardant systems. This system has disadvantages such as high specific gravity, poor flame retardancy, and easy influence by bulk commodities such as aluminum magnesium ore on the market. It can no longer meet the current market demand. Summary of the invention

[0004] In order to overcome at least one of the problems existing in the above-mentioned prior art, one of the objects of the present invention is to provide a halogen-free flame retardant material, which has the characteristics of light specific gravity, excellent flame retardant performance, and is not affected by bulk commodities. The processing equipment is simple, the cost is low, and it is easier to promote and apply.

[0005] A second object of the present invention is to provide a method for preparing the above-mentioned halogen-free flame retardant material.

[0006] A third object of the present invention is to provide a cable.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] The first aspect of the present invention provides a halogen-free flame retardant material, comprising the following raw materials in parts by weight: 8 to 30 parts of ethylene-vinyl acetate copolymer, 3 to 20 parts of polyethylene resin, 3 to 10 parts of graft compatibilizer, 40 to 70 parts of talc, 0.5 to 7 parts of liquid flame retardant, 0.5 to 7 parts of nitrogen-based flame retardant, 0.5 to 7 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant, and 1 to 8 parts of auxiliary agent.

[0009] Preferably, the liquid flame retardant includes at least one of bisphenol A-bis(diphenyl phosphate), polysiloxane or resorcinol bis(diphenyl phosphate); further preferably, the liquid flame retardant includes bisphenol A-bis(diphenyl phosphate), resorcinol bis(diphenyl phosphate) or a combination thereof; further preferably, the liquid flame retardant is selected from bisphenol A-bis(diphenyl phosphate) or resorcinol bis(diphenyl phosphate).

[0010] Preferably, the nitrogen-based flame retardant includes at least one of melamine cyanurate, melamine or melamine polyphosphate; further preferably, the nitrogen-based flame retardant is selected from one of melamine cyanurate, melamine or melamine polyphosphate; further preferably, the nitrogen-based flame retardant is selected from one of melamine cyanurate or melamine polyphosphate.

[0011] Preferably, the active substance content of the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) flame retardant is ≥95wt%; more preferably ≥98wt%; for example, it can be any value among 98%, 98.5%, 99%, 99.5%, or a range of any two values, such as 98.5-99%. The active substance content is measured by high performance liquid chromatography (HPLC).

[0012] Preferably, the mass ratio of the liquid flame retardant, the nitrogen-based flame retardant, and the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) flame retardant is 1:(0.1-5):(0.1-5); more preferably, it is 1:(0.5-3):(0.5-3); for example, it can be 1:2:1, 1:1:1, 1:1:2, etc.

[0013] Preferably, the vinyl acetate (VA) content in the ethylene-vinyl acetate copolymer (EVA) is ≥20%; more preferably ≥25%; for example, it can be any value among 25%, 30%, 40%, 50% or a range value consisting of any two of them, such as 30-50%.

[0014] Preferably, the melt index of the polyethylene (PE) resin under the test conditions of 190°C / 2.16kg is 0.5-10g / 10min; more preferably 0.8-8g / 10min; further preferably 1-5g / 10min; for example, it can be any value among 1g / 10min, 2g / 10min, 3g / 10min, 4g / 10min, 5g / 10min, or a range value composed of any two of them, such as 2-3g / 10min.

[0015] Preferably, the D50 particle size of the talc is in the range of 0.5 to 10 μm; more preferably 1 to 5 μm; further preferably 2 to 3 μm; for example, it can be any value among 2 μm, 2.2 μm, 2.5 μm, 2.8 μm, 3 μm, or a range of any two thereof, such as 2.5 to 2.5 μm.

[0016] In the present invention, the D50 particle size of talc refers to the particle size corresponding to when the cumulative particle size distribution percentage of talc reaches 50%. Its physical meaning is that talc particles with a particle size larger than D50 account for 50%, and talc particles with a particle size smaller than D50 also account for 50%.

[0017] Preferably, the grafted compatibilizer includes maleic anhydride grafted polyethylene; further preferably, the grafted compatibilizer is selected from maleic anhydride grafted polyethylene.

[0018] Preferably, the ratio of the total mass of the ethylene-vinyl acetate copolymer and the polyethylene resin to the mass of the talc is 1:(1.8-2.15); more preferably 1:(1.9-2.15); further preferably 1:(2-2.12).

[0019] In the present invention, ethylene-vinyl acetate copolymer and polyethylene resin are used as base resins, and a certain dosage ratio is maintained between talcum powder and the base resin, so that the talcum powder and the base resin have better adhesion, and the entanglement between molecular chains is enhanced, thereby obtaining better tensile properties. In addition, the dosage of talcum powder is more than that of the base resin, which can reduce costs, improve low smoke effects, and prevent excess performance.

[0020] Preferably, the ratio of the total mass of the ethylene-vinyl acetate copolymer and the polyethylene resin to the total mass of the liquid flame retardant, the nitrogen-based flame retardant and the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant is 1:(0.2-0.5); more preferably 1:(0.22-0.4); and even more preferably 1:(0.25-0.35).

[0021] Maintaining a certain ratio between the base resin and the flame retardant can achieve better flame retardant effects and mechanical properties.

[0022] Preferably, the halogen-free flame retardant material comprises the following raw materials in parts by mass: 10 to 25 parts of ethylene-vinyl acetate copolymer, 5 to 15 parts of polyethylene resin, 4 to 8 parts of graft compatibilizer, 45 to 65 parts of talc, 1 to 5 parts of liquid flame retardant, 1 to 5 parts of nitrogen-based flame retardant, 1 to 5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant, and 1.8 to 5 parts of auxiliary agent.

[0023] Further preferably, the halogen-free flame retardant material comprises the following raw materials in parts by mass: 14 to 20 parts of ethylene-vinyl acetate copolymer, 7 to 12 parts of polyethylene resin, 5 to 7 parts of graft compatibilizer, 50 to 60 parts of talc, 1.5 to 3 parts of liquid flame retardant, 3 to 4.5 parts of nitrogen-based flame retardant, 1.5 to 3 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant, and 2 to 4 parts of auxiliary agent.

[0024] Preferably, the auxiliary agent includes at least one of a smoke suppressant, an antioxidant or a lubricant; further preferably, the auxiliary agent includes a smoke suppressant, an antioxidant and a lubricant.

[0025] Preferably, the smoke suppressant includes at least one of zinc borate, zinc oxide or molybdenum oxide; further preferably, the smoke suppressant is selected from molybdenum oxide.

[0026] Preferably, the antioxidant includes a hindered phenolic antioxidant, an amine antioxidant or a combination thereof; further preferably, the antioxidant is selected from a compound of a hindered phenolic antioxidant and an amine antioxidant; further preferably, in the antioxidant, the mass ratio of the hindered phenolic antioxidant to the amine antioxidant is 1:(0.5-3); more preferably 1:(1-2).

[0027] Preferably, the hindered phenol antioxidant is selected from Antioxidant 1010.

[0028] Preferably, the amine antioxidant is selected from antioxidant KY405.

[0029] Preferably, the lubricant comprises silicone masterbatch; further preferably, the lubricant is selected from silicone masterbatch.

[0030] Preferably, the halogen-free flame retardant material comprises the following raw materials in parts by mass: 8 to 30 parts of ethylene-vinyl acetate copolymer, 3 to 20 parts of polyethylene resin, 3 to 10 parts of graft compatibilizer, 40 to 70 parts of talc, 0.5 to 7 parts of liquid flame retardant, 0.5 to 7 parts of nitrogen-based flame retardant, 0.5 to 7 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant, 0.6 to 4 parts of smoke suppressant, 0.1 to 2 parts of antioxidant, and 0.3 to 2 parts of lubricant.

[0031] Further preferably, the halogen-free flame retardant material comprises the following raw materials in parts by mass: 10 to 25 parts of ethylene-vinyl acetate copolymer, 5 to 15 parts of polyethylene resin, 4 to 8 parts of graft compatibilizer, 45 to 65 parts of talc, 1 to 5 parts of liquid flame retardant, 1 to 5 parts of nitrogen-based flame retardant, 1 to 5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant, 1 to 3 parts of smoke suppressant, 0.3 to 1 part of antioxidant, and 0.5 to 1 part of lubricant.

[0032] More preferably, the halogen-free flame retardant material comprises the following raw materials in parts by mass: 14 to 20 parts of ethylene-vinyl acetate copolymer, 7 to 12 parts of polyethylene resin, 5 to 7 parts of graft compatibilizer, 50 to 60 parts of talc, 1.5 to 3 parts of liquid flame retardant, 3 to 4.5 parts of nitrogen-based flame retardant, 1.5 to 3 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant, 1 to 2.2 parts of smoke suppressant, 0.4 to 0.8 parts of antioxidant, and 0.6 to 1 parts of lubricant.

[0033] The second aspect of the present invention provides a method for preparing the halogen-free flame retardant material as described in the first aspect of the present invention, comprising the following steps: mixing the raw materials, performing banburying and extrusion granulation in sequence to obtain the halogen-free flame retardant material.

[0034] Preferably, the mixing time is 3 to 20 minutes; more preferably 6 to 10 minutes.

[0035] Preferably, the temperature of the banburying is 110-140°C; more preferably, it is 120-130°C.

[0036] Preferably, the temperature of the extrusion granulation is 120-140°C; more preferably 125-135°C.

[0037] Preferably, the extrusion granulation is carried out in a single screw extruder.

[0038] A third aspect of the present invention provides a cable, wherein the raw material for preparing the cable includes the halogen-free flame retardant material described in the first aspect of the present invention.

[0039] Preferably, the specific gravity of the cable is 1.4 to 1.47 g / cm 3 ; More preferably 1.43 to 1.45 g / cm 3 .

[0040] The cable prepared by the present invention has the characteristics of light specific gravity, good flame retardant performance, low smoke and no halogen, and is more conducive to popularization and application.

[0041] The beneficial effects of the present invention are as follows: the present invention adopts ethylene-vinyl acetate copolymer and polyethylene resin as base resin, and combines a synergistic flame retardant composed of a liquid flame retardant, a nitrogen-based flame retardant, and a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant, and combines talcum powder to obtain a halogen-free flame retardant material with good mechanical properties, anti-aging properties, flame retardant properties and low smoke effects, and has good application prospects in the preparation of cables with light specific gravity and good flame retardant properties. DETAILED DESCRIPTION

[0042] The content of the present invention is further described in detail below through specific examples. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the principles set forth in the present invention all belong to the scope of protection of the present invention. The specific process parameters and the like in the following examples are also only examples within a suitable range, that is, those skilled in the art can make a selection within a suitable range through the description herein, and are not limited to the specific data exemplified below. The raw materials, reagents or devices used in the following examples and comparative examples, unless otherwise specified, can all be obtained from conventional commercial sources, or can be obtained by existing known methods.

[0043] It should be noted that some of the raw material information used in the examples and comparative examples of the present invention are as follows:

[0044] Ethylene-vinyl acetate copolymer: vinyl acetate (VA) content of 25-30%, Formosa Plastics;

[0045] PE resin: The melt index under the test conditions of 190℃ / 2.16kg is 1-5g / 10min, Dow;

[0046] Graft compatibilizer: maleic anhydride grafted polyethylene, Shanghai Jiuju;

[0047] Talc: particle size D50 ranges from 2 to 3 μm, Huajun;

[0048] Liquid flame retardant: bisphenol A-bis(diphenyl phosphate), Guolan New Materials (Shandong) Co., Ltd.; resorcinol bis(diphenyl phosphate), Shandong Luqixing Environmental Protection Technology Co., Ltd.;

[0049] Nitrogen flame retardants: melamine cyanurate, Qingyuan Pusev; melamine, Suzhou Dongbai Chemical Co., Ltd.; melamine polyphosphate, Shouguang Weidong Chemical Co., Ltd.;

[0050] 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant: active substance content ≥ 98%, the content is measured by high performance liquid chromatography (HPLC), Jiangyin Hanfeng Technology Co., Ltd.;

[0051] Smoke suppressant: molybdenum oxide, Taizhou Best;

[0052] Antioxidant: Antioxidant 1010, BASF; Antioxidant DLTP, Changzhou Jiatong Chemical;

[0053] Lubricant: Silicone masterbatch, Baiya.

[0054] Examples 1 to 4 and Comparative Examples 1 to 3

[0055] Examples 1 to 4 and Comparative Examples 1 to 3 each provide a halogen-free flame retardant material, and the specific raw materials and their amounts are shown in Table 1:

[0056] Table 1 Raw materials and their dosages of Examples 1 to 4 and Comparative Examples 1 to 3 (dosage units are parts by mass)

[0057]

[0058] The preparation methods of the halogen-free flame retardant materials of Examples 1 to 4 and Comparative Examples 1 to 3 are as follows:

[0059] 1) Weigh the raw materials of each component according to the mass parts shown in Table 1, and mix them in a blender for 6 to 10 minutes;

[0060] 2) Put it into an internal mixer set at a temperature of 120 to 130° C. and mix for 20 to 30 minutes;

[0061] 3) The rubber mass after internal mixing is put into a single screw extruder with a set temperature of 125-135° C. for granulation to obtain a halogen-free flame retardant material.

[0062] Performance Testing

[0063] The performance of the halogen-free flame retardant materials of Examples 1 to 4 and Comparative Examples 1 to 3 was tested, and the test items and implementation standards are as follows:

[0064] (1) Specific gravity: ASTM D 792-2022;

[0065] (2) Tensile strength, elongation at break, retention of tensile strength after aging at 110°C / 240h, retention of elongation at break after aging at 110°C / 240h: GB / T 1040.2-2022;

[0066] (3) Hardness D: ASTM D2240-15 (2021);

[0067] (4) Oxygen index: GB / T 2406.2-2009;

[0068] (5) Smoke density: GB / T 17651.1-2021, GB / T 17651.2-2021;

[0069] (6) Single vertical burning test: GB / T 18380.11-2022, GB / T 18380.12-2022, GB / T18380.13-2022;

[0070] (7) Bundle combustion test: GB / T 18380.31-2022, GB / T 18380.35-2022.

[0071] The test results are shown in Table 2.

[0072] Table 2 Performance test results of halogen-free flame retardant materials of Examples 1 to 4 and Comparative Examples 1 to 3

[0073]

[0074] From the test data in Table 2, it can be seen that the tensile properties of Examples 1 to 4 are all good and can meet the required indicators; while the tensile properties of Comparative Examples 1 to 3 are relatively poor. The analysis is that the base resin is less and the talcum powder is more, the adhesion between the talcum powder and the base resin is reduced, and the entanglement between the molecular chains is weakened, resulting in a decrease in tensile properties. The aging properties of Examples 1 to 4 and Comparative Examples 1 to 3 at 110°C / 240h can meet the standard requirements, while Example 2 is relatively poor, mainly because the melamine has poor heat resistance and is easily decomposed and remains during processing, resulting in aging deterioration.

[0075] The oxygen index is obviously different from the data. Examples 1 to 4 are obviously better than Comparative Examples 1 to 3. The oxygen index of Example 2 reaches 38%, mainly because melamine releases the most gas during combustion, which blocks the oxygen around the flame to achieve a good extinguishing effect, and also affects the smoke density, but the smoke density can also meet the requirements. The oxygen index of Comparative Example 2 is not up to standard, which shows that relying solely on the surface dehydration and carbonization of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant cannot block the spread of flames.

[0076] Comparative Examples 2 to 3 did not pass the single vertical combustion test. It can be seen that the lack of liquid flame retardant or 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant will result in the inability of the two to play a synergistic promoting role, resulting in poor carbonization efficiency during the combustion process, and the inability to capture the free radicals generated during the combustion process, causing the flame to continue to spread.

[0077] The bundle combustion test was significantly different, and Example 2 failed the test. It can be seen that although the oxygen index of the melamine flame retardant system is very high, the decomposition temperature of melamine during combustion is low, and it cannot achieve synchronous synergistic effect with other flame retardants. All the bundle combustion tests of Comparative Examples 1 to 3 failed. Comparative Example 1 was due to too little addition of flame retardant, and Comparative Examples 2 to 3 were due to the lack of liquid flame retardant or 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant, resulting in no synergistic gain effect.

[0078] The halogen-free flame retardant material prepared in the embodiment of the present invention uses ethylene-vinyl acetate copolymer and polyethylene resin as the resin matrix, which has universal applicability and is conducive to large-scale application; the resin matrix is ​​combined with talcum powder and a specific flame retardant compound, and the prepared halogen-free flame retardant material has excellent flame retardant properties, light specific gravity, and is not affected by bulk commodities. When this material is used to prepare cables, it can not only meet the single vertical combustion performance required by GB / T 18380.1 and the bundled combustion performance required by GB / T18380.3, but also the cables are lighter and the raw material supply is stable. In addition, the halogen-free flame retardant material also has the advantages of simple processing technology and low cost.

[0079] In summary, the present invention adopts ethylene-vinyl acetate copolymer and polyethylene resin as the base resin, and combines a synergistic flame retardant composed of a liquid flame retardant, a nitrogen-based flame retardant, and a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant, and talcum powder to obtain a halogen-free flame retardant material having good mechanical properties, anti-aging properties, flame retardant properties and low smoke effects, and has good application prospects in the preparation of cables with light specific gravity and good flame retardant properties.

Claims

1. A halogen-free flame retardant material, characterized in that: The invention comprises the following raw materials in parts by weight: 8 to 30 parts of ethylene-vinyl acetate copolymer, 3 to 20 parts of polyethylene resin, 3 to 10 parts of graft compatibilizer, 40 to 70 parts of talc, 0.5 to 7 parts of liquid flame retardant, 0.5 to 7 parts of nitrogen flame retardant, 0.5 to 7 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant and 1 to 8 parts of auxiliary agent.

2. The halogen-free flame retardant material according to claim 1, characterized in that: The liquid flame retardant includes at least one of bisphenol A-bis(diphenyl phosphate), polysiloxane or resorcinol bis(diphenyl phosphate); And / or, the nitrogen-based flame retardant includes at least one of melamine cyanurate, melamine or melamine polyphosphate.

3. The halogen-free flame retardant material according to claim 1, characterized in that: The vinyl acetate content in the ethylene-vinyl acetate copolymer is ≥ 20%; And / or, the polyethylene resin has a melt index of 0.5 to 10 g / 10 min under the test conditions of 190° C. / 2.16 kg; And / or, the D50 particle size of the talc is in the range of 0.5 to 10 μm.

4. The halogen-free flame retardant material according to claim 1, characterized in that: The grafted compatibilizer includes maleic anhydride grafted polyethylene.

5. The halogen-free flame retardant material according to claim 1, characterized in that: The ratio of the total mass of the ethylene-vinyl acetate copolymer and the polyethylene resin to the mass of the talc is 1:(1.8-2.15); And / or, the ratio of the total mass of the ethylene-vinyl acetate copolymer and the polyethylene resin to the total mass of the liquid flame retardant, the nitrogen flame retardant and the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardant is 1: (0.2～0.5)。 6. The halogen-free flame retardant material according to claim 1, characterized in that: The auxiliary agent includes at least one of a smoke suppressant, an antioxidant or a lubricant.

7. The halogen-free flame retardant material according to claim 6, characterized in that: The smoke suppressant comprises at least one of zinc borate, zinc oxide or molybdenum oxide; and / or, the antioxidant comprises a hindered phenol antioxidant, an amine antioxidant or a combination thereof; And / or, the lubricant comprises silicone masterbatch.

8. A method for preparing a halogen-free flame retardant material as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: The raw materials are mixed, and then subjected to banburying and extrusion granulation in sequence to obtain the halogen-free flame retardant material.

9. The preparation method according to claim 8, characterized in that: The mixing time is 3 to 20 minutes; And / or, the temperature of the banburying is 110-140°C; And / or, the temperature of the extrusion granulation is 120-140°C.

10. A cable, characterized in that: The raw material for preparing the cable comprises the halogen-free flame retardant material according to any one of claims 1 to 7.

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