Halogen-free flame-retardant low-smoke ABS composite material and preparation method thereof

Abstract

The application belongs to the technical field of flame-retardant polymer materials, and particularly relates to a halogen-free flame-retardant low-smoke ABS composite material and a preparation method thereof. The halogen-free flame-retardant low-smoke ABS composite material is prepared from the following components in parts by weight: 75-80 parts of ABS resin, 18-25 parts of intumescent flame retardant, 2-5 parts of mixed smoke suppressant, 1-3 parts of compatibilizer, and 5-10 parts of toughening agent. The halogen-free flame-retardant smoke-suppressing ABS composite material has the technical advantages of good flame-retardant performance and effective reduction of toxic smoke release.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flame-retardant high polymer materials, and particularly relates to a halogen-free flame-retardant low-smoke ABS composite material and a preparation method thereof. BACKGROUND

[0002] ABS is a ternary copolymer of acrylonitrile, butadiene and styrene, and is an engineering plastic with extremely wide application. Its main advantages lie in its excellent comprehensive mechanical properties: high strength, good toughness, and not bad hardness, which makes it very suitable for manufacturing products that need to withstand external force or are often held. In addition, ABS also has good processing performance and is easy to be molded by injection molding, extrusion and other methods, with high production efficiency. However, the disadvantage of ABS is also obvious, and the limiting oxygen index (LOI) of pure ABS is about 18%, which means that it can easily burn in air. The combustion process is relatively violent, usually accompanied by the generation of a large amount of dense black smoke and molten dripping phenomenon, and emits a special irritating smell, which greatly limits its application range.

[0003] The patent "Environment-friendly high-toughness flame-retardant ABS composition, preparation method and application thereof" (CN119775682A) uses antimony trioxide and bromine-containing triazine, hexabromocyclododecane and other halogen flame retardants in combination to improve the flame retardant properties of ABS. Although it has good flame retardant effect at low addition amount, halogen flame retardants are too harmful to the environment, and the application field will be greatly limited.

[0004] The patent "Impact-resistant flame-retardant ABS material and preparation method thereof" (CN120059396A) discloses a more environmentally friendly intumescent flame retardant for the flame-retardant modification of ABS. The intumescent flame retardant is composed of a piperazine flame retardant (piperazine pyrophosphate), a hypophosphite flame retardant (aluminum hypophosphite and / or diethyl aluminum hypophosphite) and / or a nitrogen flame retardant (melamine polyphosphate). This scheme can improve the flame retardant properties of ABS, but the toxic smoke problem of ABS has not been solved.

[0005] The patent "Flame-retardant ABS composite material, preparation method and application thereof" (CN113930044B) discloses a flame-retardant ABS composite material: including ABS resin 60-90 parts, intumescent flame retardant 10-30 parts, nano particles 0.5-10 parts, and processing aid 0-2.5 parts. The intumescent flame retardant is selected from one or at least two of pentaerythritol, melamine, ammonium polyphosphate, aluminum hypophosphite, diethyl aluminum hypophosphite, expandable graphite, graphene oxide, triazine, urea, cyclodextrin, red phosphorus, aluminum hypophosphite, diethyl aluminum hypophosphite, ammonium phytate, piperazine pyrophosphate, pentaerythritol phosphate, pentaerythritol phosphate diester or cyclotriphosphazene.

[0006] Patent CN118852835B discloses a preparation method of halogen-free low-smoke flame-retardant ABS, adding graphene-loaded halogen-free flame retardant, and using cobalt nitrate and magnesium nitrate to prepare smoke suppressant by nucleation-crystallization isolation method. Although the limiting oxygen index of ABS is improved and the release amount of toxic smoke is obviously inhibited. However, since the added flame retardant mainly plays a role in the condensed phase, it does not have obvious effect in the vertical burning test of UL-94. In addition, the preparation method of this modification is complicated and the raw materials such as graphene are expensive, which has strong limitations in production cost. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a halogen-free flame-retardant low-smoke ABS composite material and a preparation method thereof.

[0008] In order to solve the above technical problems, the present application provides a halogen-free flame-retardant low-smoke ABS composite material, which is composed of the following components by weight: 75-80 parts of ABS resin, 18-25 parts of intumescent flame retardant, 2-5 parts of mixed smoke suppressant, 1-3 parts of compatibilizer, and 5-10 parts of toughening agent.

[0009] Improvements of the halogen-free flame-retardant low-smoke ABS composite material of the present application:

[0010] The intumescent flame retardant is a phosphorus-based flame retardant;

[0011] The mixed smoke suppressant is obtained by mixing zinc phosphomolybdate and alpha-zirconium phosphate in a mass ratio of 2-3:1;

[0012] The compatibilizer is a polystyrene maleic anhydride copolymer;

[0013] The toughening agent is high glue powder.

[0014] Further improvements of the halogen-free flame-retardant low-smoke ABS composite material of the present application:

[0015] The phosphorus-based flame retardant is at least any one of piperazine pyrophosphate (PAPP), aluminum hypophosphite (ALHP), and aluminum diethyl hypophosphite (ADP).

[0016] Further improvements of the halogen-free flame-retardant low-smoke ABS composite material of the present application:

[0017] The intumescent flame retardant is obtained by mixing piperazine pyrophosphate (PAPP) and aluminum diethyl hypophosphite (ADP) in a mass ratio of (3±0.1):1;

[0018] Alternatively, the intumescent flame retardant is obtained by mixing piperazine pyrophosphate (PAPP) and aluminum hypophosphite (ALHP) in a mass ratio of (4±0.1):1.

[0019] As a further improvement of the halogen-free flame-retardant low-smoke ABS composite material of the present application:

[0020] The formula is composed of the following ingredients by weight: 79-81 parts of ABS resin, 17.5-18.5 parts of intumescent flame retardant, 1.8-2.2 parts of mixed smoke suppressant, 0.9-1.1 parts of compatibilizer, 4.5-5.5 parts of toughening agent.

[0021] Further, the formula is composed of the following ingredients by weight: 80 parts of ABS resin, 18 parts of intumescent flame retardant, 2 parts of mixed smoke suppressant, 1 part of compatibilizer, and 5 parts of toughening agent.

[0022] The present application also simultaneously provides a preparation method of the above-mentioned halogen-free flame-retardant low-smoke ABS composite material, comprising the following steps:

[0023] 1) The ABS resin, intumescent flame retardant, mixed smoke suppressant, compatibilizer and toughening agent weighed according to the formula are pre-mixed in a high-speed mixer at high speed (rotation speed of 300±50 r / min).

[0024] 2) The mixed material obtained in step 1) is subjected to melting, shearing and extrusion granulation (a double-screw extruder can be used), to obtain a halogen-free flame-retardant low-smoke ABS composite material.

[0025] As an improvement of the preparation method of the halogen-free flame-retardant low-smoke ABS composite material of the present application, the pre-mixing temperature in step 1) is 80±5℃, and the pre-mixing time is 5±1 minutes.

[0026] As a further improvement of the preparation method of the halogen-free flame-retardant low-smoke ABS composite material of the present application, the extrusion temperature in step 2) is 190-230℃, the rotation speed is 450 r / min, and the feeding rotation speed is 30 r / min.

[0027] As a further improvement of the preparation method of the halogen-free flame-retardant low-smoke ABS composite material of the present application, the particle size of the obtained halogen-free flame-retardant low-smoke ABS composite material is 2-3 mm.

[0028] In the present application:

[0029] The phosphorus flame retardant not only has no environmental pollution, but also has strong flame retardant effect. The thermal decomposition temperature of the pyrophosphoric acid piperazine is suitable for ABS, and the addition of aluminum hypophosphite or aluminum diethyl hypophosphite for compounding can achieve good flame retardant effect with low addition amount, but the release amount of toxic smoke is still large. Therefore, the zinc phosphomolybdate and the alpha-zirconium phosphate are introduced as smoke suppressants of the composite material. In addition to the thermal decomposition of the zinc phosphomolybdate and the alpha-zirconium phosphate to generate phosphorus oxygen radicals to achieve the effect of gas phase flame retardant, it is found through experimental research that the two can catalyze the ABS composite material to form a high-quality carbon layer, thereby reducing the release of toxic smoke. This is because the zinc phosphomolybdate and the alpha-zirconium phosphate will synergistically act during combustion, and through their own acidic sites, they catalyze the dehydration, aromatization and crosslinking reaction of ABS, effectively converting the polymer carbon source into a stable protective carbon layer instead of volatile black smoke particles. The pyrophosphoric acid piperazine and other phosphorus flame retardants are rigid particles, which are easy to agglomerate in the matrix, and have an adverse effect on the impact resistance of ABS. Therefore, the polystyrene maleic anhydride copolymer is added in the present application to improve the dispersibility of the flame retardant in the matrix and reduce the degradation of the impact resistance caused by phase separation and stress concentration. In addition, a small amount of high glue powder as a toughening agent is also added. The high glue powder is essentially an ABS resin with ultra-high rubber content, which will be uniformly dispersed in the brittle flame-retardant ABS matrix after mixing and processing, forming new and stronger stress concentration points to improve the impact resistance of the flame-retardant ABS.

[0030] In summary, the present application enhances the flame retardant performance of ABS and reduces the release of toxic smoke by adding pyrophosphoric acid piperazine, aluminum hypophosphite or diethyl aluminum hypophosphite, zinc phosphomolybdate and alpha-zirconium phosphate in a specific ratio. And the polystyrene maleic anhydride copolymer and high glue powder are added to improve the impact resistance of the flame-retardant ABS, thereby preparing a halogen-free flame-retardant low-smoke ABS composite material. DETAILED DESCRIPTION

[0031] The present application will be further described below in conjunction with specific examples, but the scope of protection of the present application is not limited to this:

[0032] The raw materials used in the examples of the present application are all commonly used in the art. For example:

[0033] The ABS resin can be purchased from Chimei Chemical Co., Ltd. PA-709.

[0034] The pyrophosphoric acid piperazine (PAPP) can be purchased from Shaoxing Xingxin New Material Co., Ltd.

[0035] Aluminum hypophosphite (article number: A759044), aluminum diethylphosphinate (article number: A303123) and zirconium alpha-phosphate (article number: Z597580) are available from Shanghai Aldrin Biochemical Technology Co., Ltd.

[0036] Zinc phosphomolybdate (article number: JP-B900) is available from Shanghai Junjiang Technology Co., Ltd.

[0037] Polystyrene maleic anhydride copolymer, CAS number: 9011-13-6 (article number: S729102) is available from Shanghai Macklin Biochemical Technology Co., Ltd. (molecular weight 9500, acid value: 265-305 mg KOH / g).

[0038] High glue powder (ABS high glue powder, article number: EB-168) is available from Shandong Yigong Material Technology Co., Ltd.

[0039] The following parts are parts by weight.

[0040] PAPP represents piperazine pyrophosphate, ALHP represents aluminum hypophosphite, and ADP represents diethylphosphinic acid aluminum.

[0041] Example 1, a halogen-free flame-retardant low-smoke ABS composite material, the formula is as follows: 80 parts of ABS, 18 parts of intumescent flame retardant, 2 parts of mixed smoke suppressant, 1 part of compatibilizer, 5 parts of toughening agent;

[0042] The preparation method is to sequentially perform the following steps:

[0043] 1), according to the formula, ABS resin, intumescent flame retardant, mixed smoke suppressant, compatibilizer and toughening agent are weighed, and high-speed (rotating speed is 300 r / min) premixing is carried out in a high-speed mixer, the premixing temperature is 80 ℃, and the premixing time is 5 minutes;

[0044] The intumescent flame retardant is obtained by mixing PAPP:ADP=3:1 by mass ratio;

[0045] The mixed smoke suppressant is obtained by mixing zinc phosphomolybdate:zirconium alpha-phosphate=2:1 by mass ratio;

[0046] The compatibilizer is polystyrene maleic anhydride copolymer;

[0047] The toughening agent is high glue powder.

[0048] 2), the mixed material obtained in step 1) is melted, sheared and extruded and granulated by using a twin-screw extruder, the extrusion temperature is 190~230 ℃, the rotating speed is 450 r / min, and the feeding rotating speed is 30 r / min. The particle size is about 2~3mm.

[0049] Example 2~Example 6, the formulation was changed (the formulation is shown in Table 1), the preparation method is equivalent to Example 1.

[0050] Table 1: Component ingredients of the flame-retardant polypropylene composition

[0051]

[0052] Performance evaluation of polypropylene composite:

[0053] 1. The test conditions and standards of flame retardant performance are as follows:

[0054] UL-94 vertical burning sample size: 130x13x1.6 mm 3 , test standard: ASTM D3801;

[0055] Limiting oxygen index sample size: 100x6.5x3.2 mm 3 , test standard: ASTM 2863;

[0056] 2. Smoke density test conditions and standards:

[0057] Smoke density was tested by smoke density meter (5920 type), the radiation intensity was 25 kW / m 2 , no ignition flame, sample size was 75x75x3 mm 3 , the test standard was GB / T8323-2008. The maximum specific optical density (max) is an index to measure the size of plastic smoke, also known as the maximum smoke density. The larger the maximum specific optical density, the greater the smoke emission, the thicker the black smoke during combustion, and the greater the environmental pollution. D

[0058] 3. Impact resistance test conditions and standards:

[0059] Sample size was 80x10x4 mm 3 , with a 2mm V-shaped notch, notch impact test was carried out on XJ-50Z impact tester, the impact energy of pendulum was 2.75J, and the test standard was ISO179-1:98.

[0060] The test results are as follows in Table 2.

[0061] Table 2: Test results of each performance of ABS composite

[0062]

[0063] ​Note: In the above cases, Example 1 is the case with the least amount of intumescent flame retardant (relative to the amount of ABS resin), which achieves a V0 flame retardant rating and excellent notched impact strength, and also effectively achieves a smoke suppression effect, so Example 1 is the preferred case.

[0064] Blank Comparative Example: That is, pure ABS; that is, the difference from Example 1 is that no intumescent flame retardant, smoke suppression agent, compatibilizer, and toughening agent are added.

[0065] Comparative Example 1-1, the difference from Example 1 is that the formula of the mixed smoke suppression agent is changed from "zinc phosphomolybdate: alpha-zirconium phosphate = 2:1" to "zinc phosphomolybdate: alpha-zirconium phosphate = 1:1"; the rest is the same as Example 1.

[0066] Comparative Example 1-2, the difference from Example 1 is that the amount of mixed smoke suppression agent is changed from "2 parts" to "6 parts", the rest is the same as Example 1.

[0067] Comparative Example 1-3, the difference from Example 1 is that the amount of mixed smoke suppression agent is changed from "2 parts" to "1 part", the rest is the same as Example 1.

[0068] Comparative Example 1-4, the difference from Example 1 is that the mixed smoke suppression agent is changed to zinc phosphomolybdate, the amount remains the same, still 2 parts; the rest is the same as Example 1.

[0069] Comparative Example 1-5, the difference from Example 1 is that the mixed smoke suppression agent is changed to alpha-zirconium phosphate, the amount remains the same, still 2 parts; the rest is the same as Example 1.

[0070] Comparative Example 1-6, the difference from Example 1 is that the mixed smoke suppression agent is changed to antimony trioxide (a commonly used smoke suppression agent), the amount remains the same, still 2 parts; the rest is the same as Example 1.

[0071] Comparative Example 1-7, the difference from Example 1 is that the mixed smoke suppression agent is changed to molybdenum trioxide (a commonly used smoke suppression agent), the amount remains the same, still 2 parts; the rest is the same as Example 1.

[0072] Comparative Example 1-8, the difference from Example 1 is that the zinc phosphomolybdate in the mixed smoke suppression agent is changed to aluminum phosphomolybdate, the amount remains the same; the rest is the same as Example 1.

[0073] Comparative Example 1-9, the difference from Example 1 is that the alpha-zirconium phosphate in the mixed smoke suppression agent is changed to zirconium dioxide, the amount remains the same; the rest is the same as Example 1.

[0074] Comparative Example 2, the difference from Example 3 is that the compatibilizer polystyrene maleic anhydride copolymer is not added, the rest is the same as Example 3.

[0075] Comparative Example 3 differs from Example 6 in that no toughening agent high glue powder is added, and the rest is the same as Example 6.

[0076] Comparative Example 4, change "ABS resin 75 parts, intumescent flame retardant 25 parts" in Example 3 to "ABS resin 80 parts, intumescent flame retardant 18 parts" as described in Example 1, and the rest is the same as Example 3.

[0077] The above cases are detected according to the above performance evaluation, and the results are as shown in Table 3.

[0078] Table 3

[0079]

[0080] From the above, it can be seen that Examples 1-6 of the present application can pass the UL-94 vertical burning test and reach the V0 level, and the limiting oxygen index also increases from 18.2% to more than 28%, from flammable material to difficult flammable material. In addition, the smoke density is reduced from 685 of pure ABS to below 430, and the smoke density of Example 3 is reduced to 345, a decrease of 49.6%, greatly reducing the release amount of toxic smoke.

[0081] Comparative Example 1-1 changes the mass ratio between the mixed smoke suppressant, and changes "zinc phosphomolybdate: alpha-zirconium phosphate = 3:1" to "zinc phosphomolybdate: alpha-zirconium phosphate = 1:1". The flame retardant test result shows that it decreases from V0 level to V1 level. This is because in the smoke suppressant, zinc phosphomolybdate plays a major catalytic carbonization role, and alpha-zirconium phosphate is an auxiliary role. When the mass of the two is the same, it cannot play a significant catalytic role, and there are certain voids in the carbon layer formed, resulting in a second burning time exceeding 10 S, and only reaching V1 level.

[0082] Comparative Example 1-2 changes the addition amount of the mixed smoke suppressant, and increases the addition amount of the mixed smoke suppressant from "2 parts" to "6 parts". The result shows that the flame retardant performance does not increase but decreases, and the notched impact strength decreases from 13.5 to 10.7 KJ / m 2 This is because the two smoke suppressants are inorganic additives, and when the amount is too large, it is extremely easy to agglomerate in the matrix, which leads to insufficient catalytic carbonization effect during combustion, and stress concentration points are easily generated, which leads to a significant decrease in flame retardant performance and impact resistance.

[0083] Comparative Example 1-3, the addition of the mixed smoke suppressant changed, the mixed smoke suppressant from "2 parts" to "1" parts, the flame retardant test results found that the original V0 level decreased to V1 level, and the smoke density also increased from 425 to 497. This is because when the mixed smoke suppressant is too small, the flame-retardant and smoke-suppressing effect is limited, thus leading to a decrease in flame retardant performance.

[0084] Comparative Example 1-4 and Comparative Example 1-5 are added with the same amount of single smoke suppressant, and the flame retardant test results are also reduced to no flame retardant grade, which also shows that only the mixed smoke suppressant can play the best flame-retardant effect.

[0085] Comparative Example 1-6 and Comparative Example 1-7 are added with the same amount of commonly used smoke suppressant antimony trioxide and molybdenum trioxide on the market. The test results show that the flame retardant grade is also no flame retardant grade. Because antimony trioxide and molybdenum trioxide do not contain flame-retardant elements, and antimony trioxide and molybdenum trioxide can only play a significant catalytic carbonization effect when compounded with bromine-based flame retardants. The zinc phosphomolybdate and alpha-zirconium phosphate of the present application not only can burn and decompose to generate phosphorus-oxygen radicals to capture active radicals in the air during combustion, achieving gas-phase flame retardation, but also can catalyze carbonization together with intumescent flame retardants, achieving high-efficiency flame retardation.

[0086] Comparative Example 1-8 changes the zinc phosphomolybdate in the mixed smoke suppressant to the same amount of aluminum phosphomolybdate, and the vertical combustion test results directly decrease from V0 level to V1 level. This is mainly because the catalytic carbonization effect of zinc ions in zinc phosphomolybdate is stronger than that of aluminum ions, so when it is replaced by aluminum phosphomolybdate, the carbon layer formed is not dense enough, leading to a too long second combustion time, and thus only V1 level can be achieved.

[0087] Comparative Example 1-9 changes the alpha-zirconium phosphate in the mixed smoke suppressant to the same amount of zirconium oxide, and the vertical combustion test results directly decrease from V0 level to no level. The acidic hydrogen ions in alpha-zirconium phosphate can not only catalyze the dehydration of polymers (ABS resin) and flame retardants (intumescent flame retardants) to form carbon, but also generate phosphorus-oxygen radicals to play a gas-phase flame-retardant role. Zirconium dioxide does not have these effects, so the flame-retardant level is severely reduced.

[0088] Comparative Example 2 does not add a compatibilizer polystyrene maleic anhydride copolymer, and the impact strength directly decreases from 10.3 to 6.2 KJ / m 2 , a decrease of 39.8%. This is because polystyrene maleic anhydride copolymer can act as a "bridge" to connect the flame retardant with ABS, so that the flame retardant can be uniformly dispersed in the matrix. When no compatibilizer is added, stress concentration occurs, leading to a decrease in impact performance.

[0089] Comparative Example 3 did not add toughening agent high glue powder, the impact strength directly from 9.5 reduced to 2.5 KJ / m 2 , reduced by 73.7%, which also shows that high glue powder plays a good effect in toughening. The addition of high glue powder can compensate for the destruction of the "sea-island" structure of the ABS matrix caused by the addition of a large amount of flame retardant to a certain extent. When the material is impacted, the rubber particles in the high glue powder can initiate crazing and shear bands, absorb energy, and achieve toughening effect.

[0090] Comparative Example 4 changed "ABS resin 75 parts, intumescent flame retardant 25 parts" in Example 3 to "ABS resin 80 parts, intumescent flame retardant 18 parts" as described in Example 1. The vertical combustion test directly dropped from V0 level to no level, and the limiting oxygen index also dropped to 23.7%. This is because the amount of ABS resin is increased and the amount of intumescent flame retardant is reduced, resulting in a significant decrease in flame retardant efficiency. In the smoke suppression agent and other formulations of Reference Example 3, there is no obvious flame retardant effect.

[0091] Finally, it should be noted that the above only lists several specific embodiments of the present application. Obviously, the present application is not limited to the above embodiments, but can also have many variations. All variations that can be directly derived or inferred from the disclosure of the present application by those of ordinary skill in the art should be considered within the scope of the present application.

Claims

1. Halogen-free flame-retardant low-smoke ABS composite material, characterized in that The formula is composed of the following ingredients by weight: 75-80 parts of ABS resin, 18-25 parts of intumescent flame retardant, 2-5 parts of mixed smoke suppressant, 1-3 parts of compatibilizer, 5-10 parts of toughening agent; The intumescent flame retardant is obtained by mixing piperazine pyrophosphate and aluminum diethyl phosphinate in a mass ratio of (3±0.1):1; Or, the intumescent flame retardant is obtained by mixing piperazine pyrophosphate and aluminum hypophosphite in a mass ratio of (4±0.1):1; The mixed smoke suppressant is obtained by mixing zinc phosphomolybdate and alpha-zirconium phosphate in a mass ratio of 2-3:1; The compatibilizer is polystyrene maleic anhydride copolymer; The toughening agent is high glue powder.

2. The halogen-free flame-retardant low-smoke ABS composite material according to claim 1, characterized in that: The formula is composed of the following ingredients by weight: 80 parts of ABS resin, 18 parts of intumescent flame retardant, 2 parts of mixed smoke suppressant, 1 part of compatibilizer, and 5 parts of toughening agent. The method comprises the following steps:

3. A process for the preparation of halogen-free flame-retardant low smoke ABS composites as claimed in claim 1 or 2, characterized in that 1) The ABS resin, intumescent flame retardant, mixed smoke suppressant, compatibilizer, and toughening agent weighed according to the formula are pre-mixed at high speed in a mixer; 2) The mixed material obtained in step 1) is melted, sheared, and extruded and granulated to obtain the halogen-free flame-retardant low-smoke ABS composite material. The pre-mixing temperature in step 1) is 80±5℃, and the pre-mixing time is 5±1 minutes.

4. The process for the preparation of halogen-free flame-retardant low smoke ABS composite as claimed in claim 3, wherein: The extrusion temperature in step 2) is 190-230℃, the rotation speed is 450 r / min, and the feeding rotation speed is 30 r / min.

5. A process for the preparation of halogen-free flame-retardant low smoke ABS composite as claimed in claim 4, wherein The halogen-free flame-retardant low-smoke ABS composite material obtained has a particle size of 2-3 mm.

6. The process for the preparation of halogen-free flame-retardant low smoke ABS composite as claimed in claim 5, wherein: ​

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