Burnthrough-resistant flame-retardant ABS (acrylonitrile-butadiene-styrene) resin composition and preparation method thereof

Abstract

The invention provides a burn-through-resistant flame-retardant ABS resin composition and a preparation method thereof, and the composition comprises the following components in parts by weight: 50-60 parts of ABS resin, 6-12 parts of ABS rubber powder, 14-20 parts of a flame retardant, 2-5 parts of a system flame-retardant synergist, 5-10 parts of a silicon flame-retardant synergist, 8-12 parts of a flame retardant 2 #, 3-8 parts of chlorinated polyethylene, 0.2-0.5 part of a lubricant, 0.2-0.5 part of an antioxidant and 0.1-0.2 part of an anti-dripping agent. According to the invention, the organic silicon resin easy to form a carbon layer and the silicon-containing auxiliary agent are utilized, so that the carbon forming capability and heat resistance of the ABS resin in the combustion process are improved, and the flame burnthrough resistance is improved, thereby improving the 5VA flame-retardant level; meanwhile, in order to further improve the flame-retardant stability, low-molecular-weight brominated epoxy and silicone powder are adopted as flame-retardant synergists, so that the dispersity of the flame retardant is improved.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to a burn-through resistant flame-retardant ABS resin composition and its preparation method. Background Technology

[0002] With increasing market demand and the implementation of relevant regulations, various industries, such as high-end consumer electronics, batteries, medical devices, and photovoltaics, are placing increasing demands on flame-retardant products. High flame-retardant 5VA thin-walled products are poised to become the mainstream in the future. ABS plastic is a material with excellent overall performance, and its high cost-effectiveness has led to its widespread application in various fields of production and daily life. However, it inherently lacks good flame retardancy, with a limiting oxygen index of approximately 18-20%, classifying it as a flammable material. The market primarily utilizes bromine-antimony systems for flame retardant modification to achieve flame retardant performance levels of V-2, V-1, V-0, S.2, 5VB, or 5VA, with 5VA currently representing the highest level. Although the bromine-antimony flame retardant system can effectively improve the flame retardant performance of ABS resin through a gas-phase flame retardant mechanism, achieving a V-0 flame retardant rating, the lack of char-forming ability in this system and the ABS resin itself means that commercially available flame-retardant ABS resins often fail to meet the stable 5VA flame retardant standard. To address this issue, a common practice is to add large amounts of inorganic fillers, but this often significantly reduces the physical properties of the flame-retardant ABS resin.

[0003] Currently, products with a wall thickness of 1.5mm to 2.0mm that achieve a 5VA flame retardant rating are generally expensive. Patent CN117430910 discloses a low-carbon 5VA flame retardant ABS material, its preparation method, and its application, which uses cellulose filler to achieve a 2.0mm flame retardant 5VA rating and requires a significant increase in the use of the synergistic flame retardant antimony trioxide, resulting in high costs. Patent CN114573942 discloses an ABS composition, its preparation method, and its application, which uses a large amount of mineral filler and flame retardant to achieve a 1.5mm flame retardant 5VA rating, but the ABS content is only 32.5%, making it expensive and resulting in a poor overall appearance.

[0004] In summary, existing flame retardant technologies for ABS resin suffer from drawbacks such as low flame retardant efficiency, large amounts of inorganic substances and bromine-antimony flame retardants, and poor physical properties of flame-retardant ABS. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a flame-retardant ABS resin composition that is resistant to burn-through and a method for preparing the same.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] This invention provides a burn-through resistant flame-retardant ABS resin composition, comprising the following components in parts by weight:

[0008]

[0009] In one embodiment of the present invention, the ABS resin contains 20-24% acrylonitrile and 10-15% butadiene. The ABS resin is preferably an acrylonitrile-butadiene-styrene copolymer prepared by emulsion method. The ABS resin is preferably 55-60 parts.

[0010] In one embodiment of the present invention, the ABS powder is ABS with a butadiene content higher than 60%, preferably 65%-75%. Its degree of crosslinking is 60-80%, and the particle size of the butadiene rubber is 100-300 nm. Low butadiene content results in poor toughening efficiency, and the higher the powder content, the greater the impact on vertical flame retardancy.

[0011] As one embodiment of the present invention, the flame retardant is one or more of brominated triazine, brominated epoxy, decabromodiphenyl ethane, and tetrabromobisphenol A.

[0012] Furthermore, the flame retardant is preferably a mixture of brominated triazine and brominated epoxy in a mass ratio of 6-7:1. The brominated epoxy is a low molecular weight brominated epoxy with a molecular weight of 1500-2000.

[0013] As one embodiment of the present invention, the antimony-based flame retardant synergist is one or more of antimony trioxide, antimony pentoxide, and sodium antimonate.

[0014] As one embodiment of the present invention, the silicon-based flame retardant synergist is a modified organosilicon resin and silicone powder.

[0015] Furthermore, the modified silicone resin is a silicone resin with surface grafting modification. The surface grafting modification groups are one of the following: long-chain branched structures, reactive groups, and bulky / rigid groups. The silicone contains groups that enhance melt strength and can be used to enhance melt strength.

[0016] Reactive groups include one or more of the following: double / triple bonds, epoxy / oxetine groups, acid anhydride groups, isocyanate groups, zoline groups, carboxyl and hydroxyl groups, and carbodiimide groups.

[0017] Large, rigid groups include one or more of the following: benzene ring, tert-butyl group, and cyclic structure.

[0018] The preferred modified silicone resin is DOWSIL. TM One or more of 2405 and SIC 6168P.

[0019] Furthermore, silicone powder is silicone powder containing siloxane.

[0020] The mass ratio of modified organosilicon resin to silicone powder is 8:1 to 2, preferably 8:1.5. The silicone-based flame retardant synergist is preferably 8 to 10 parts.

[0021] The silicone resin used in this invention, such as Dow's DOWSIL TM 2405 is a reactive alkoxysiloxane resin (reactive group: epoxy group), or Sloco's phenyl silicone resin SIC 6168P, which serves to improve melt strength. The silicone powder used in this invention is a silicone powder containing siloxane, which promotes dispersion.

[0022] In one embodiment of the present invention, the chlorinated polyethylene is chlorinated polyethylene with a chlorine content of 32-35%. If the chlorine content is higher than 35%, the toughening effect and thermal stability are poor; if the chlorine content is lower than 32%, its flame retardant properties will be affected.

[0023] In one embodiment of the present invention, the antioxidant is one or more of hindered phenolic antioxidants and phosphite antioxidants. The hindered phenolic antioxidant includes pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the phosphite antioxidant includes one or more of triphenyl phosphate, tris(2,4-di-tert-butylphenyl) phosphite, and pentaerythritol di(2,4-di-tert-butylphenyl) phosphite.

[0024] Furthermore, the antioxidant is preferably a mixture of hindered phenolic antioxidants and phosphite antioxidants. The mass ratio of hindered phenolic antioxidants to phosphite antioxidants is 1:1 to 2.

[0025] As one embodiment of the present invention, the lubricant includes one or more of fatty acid amide lubricants, stearate lubricants, fatty acid ester lubricants, and silicone lubricants.

[0026] In one embodiment of the present invention, the anti-dripping agent is polytetrafluoroethylene (PTFE) with a molecular weight of 500,000 to 2,000,000. Preferably, it is PTFE with a shell surface treated with organosilicon. Coating with 50% PTFE content facilitates the dispersion of PTFE in the system.

[0027] The present invention also provides a method for preparing the burn-through resistant flame-retardant ABS resin composition, comprising the following steps:

[0028] (1) Prepare the components according to the following parts by weight:

[0029]

[0030]

[0031] (2) Add each component in step (1) to a high-speed mixer according to the above weight proportions, mix thoroughly, and then place it in a screw extruder for melt extrusion at an extrusion temperature of 200-250°C and a screw speed of 300-500 rpm. Cool and granulate to obtain a flame-retardant ABS resin composition that is resistant to burn-through.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) This invention provides a burn-through resistant flame-retardant ABS resin composition and its preparation method. This composition exhibits excellent performance and stable flame-retardant effect. Furthermore, the preparation process utilizes the synergistic effect of gas-phase flame retardancy of the bromine-antimony system and condensed-phase flame retardancy of the silicon-based flame retardant. This preparation method significantly improves the flame-retardant efficiency while eliminating the need for inorganic fillers and reducing the amount of bromine and antimony used, thereby enhancing the flame-retardant performance and material properties of the ABS resin.

[0034] (2) By using an organosilicon resin with a modified surface to introduce a long-chain branched structure and reactive groups, the present invention improves the char-forming ability and heat resistance of ABS resin during combustion, and improves the flame burn-through resistance, thereby improving the 5VA flame retardant level.

[0035] (3) To further improve flame retardant stability, this invention uses low molecular weight brominated epoxy and silicone powder as flame retardant synergists, which improves the dispersibility of the flame retardant. At the same time, brominated epoxy can also act as a flame retardant, reducing the amount of brominated triazine added. Detailed Implementation

[0036] The present invention will be described in detail below with reference to embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several adjustments and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0037] The raw materials used in the embodiments and comparative examples of this invention are all commercially available, but are not limited to the following materials:

[0038] ABS resin: KF-730 (acrylonitrile content 20-24%, butadiene content 10-15%), Liaoning Jinfeng;

[0039] ABS Powder-1: EB-168 (particle size 300nm), with butadiene content of 70%, Shandong Yigong Materials Technology Co., Ltd.;

[0040] ABS Powder-2: D / P181 (particle size 370nm), with butadiene content of 60%, from Kumho Chemical Co., Ltd., South Korea;

[0041] Flame retardants: Bromotriazine, FR245, Dead Sea bromine; Brominated epoxy, KBE-3014, Kaiji Chemical;

[0042] Antimony-based flame retardant synergist: Antimony trioxide;

[0043] Silicone-based flame retardant synergists: Organosilicon resin, DOWSIL TM 2405, Dow; SIC 6168P, Slocor; KR-220, Shin-Etsu; Silicone powder, SG-100, Zhejiang Jiahua Fine Chemicals;

[0044] Chlorinated polyethylene: CPE135C (chlorine content 25-28%);

[0045] Antioxidants: Antioxidant 1076, Antioxidant 168;

[0046] Lubricant: EBS;

[0047] Anti-dripping agent: PTFE.

[0048] Examples 1-4

[0049] The weight proportions of the formulation components in this embodiment of the invention are shown in Table 1, and the preparation method is as follows:

[0050] According to the weight proportions of the ingredients in Table 1, the raw materials are added to a high-speed mixer and mixed thoroughly. Then, the mixture is placed in a twin-screw extruder and melt-extruded at an extrusion temperature of 200-240℃ and a screw speed of 500 rpm. After cooling and granulation, the product is obtained.

[0051] Table 1. Parts by weight of the formulations in the examples and comparative examples

[0052]

[0053] Comparative Example 1

[0054] The weight proportions of the components in the comparative formulation of this invention are shown in Table 1. The preparation method is the same as that in the examples, except that: 16 parts of bromotriazine and 0 parts of brominated epoxy are used.

[0055] Comparative Example 2

[0056] The weight proportions of the components in the comparative formulation of this invention are shown in Table 1. The preparation method is the same as that in the examples, except that: 0 parts of bromotriazine and 16 parts of brominated epoxy.

[0057] Comparative Example 3

[0058] The weight proportions of the components in the comparative formulation of this invention are shown in Table 1. The preparation method is the same as in the examples, except that: the organosilicon resin DOWSIL TM 2405 1.5 parts, silicone powder 8 parts. The silicone powder acts as a lubricant; excessive addition will affect the melt viscosity and the stability of the carbon layer.

[0059] Comparative Example 4

[0060] The weight proportions of the components in the comparative formulation of this invention are shown in Table 1. The preparation method is the same as that in the examples, except that no ABS adhesive powder is added.

[0061] Comparative Example 5

[0062] The weight proportions and preparation methods of the components in the comparative formulation of this invention are basically the same as those in Example 1, except that: the organosilicon resin DOWSIL is used. TM 2405 was replaced with silicate.

[0063] Comparative Example 6

[0064] The weight proportions of the components in the comparative formulation of this invention are shown in Table 1. The preparation method is the same as in the examples, except that: the organosilicon resin DOWSIL is used. TM 2405 was replaced by Shin-Etsu's methyl silicone resin KR-220.

[0065] Performance testing:

[0066] After drying the above products in a forced-air oven at 85°C for 5 hours, they were injection molded into standard specimens under the same injection molding conditions according to ASTM standards for mechanical property testing. Flame retardancy tests were conducted on standard UL94 specimens (thicknesses of 1.6mm and 2mm) and 5V specimens (150mm*150mm*2.0mm) at an injection temperature of 220°C.

[0067] The specific test conditions and standards are shown in Table 2:

[0068] Table 2 Test Standards and Conditions

[0069]

[0070]

[0071] The performance test results of the modified materials prepared in the examples and comparative examples are shown in Table 3.

[0072] Table 3 Summary of specific performance of the examples and comparative examples

[0073]

[0074] Compared with Example 1 and Comparative Examples 1 and 2, using 14 parts of brominated triazine combined with 2 parts of brominated epoxy can improve the flame retardant efficiency. The low molecular weight brominated epoxy promotes the dispersion of the flame retardant and improves the flame burn-through resistance. Using a single brominated flame retardant is unstable in the burn-through test, and the burn-through time varies greatly. In the 5VA test, the burn-through times of the five samples in Comparative Example 1 were 45s, 30s, 40s, 42s and passed, respectively; the burn-through times of the five samples in Comparative Example 2 were 35s, 33s, 40s, 37s and 33s, respectively. The worst burned through in 30s and the best passed the burn-through test.

[0075] Compared with Example 1 and Comparative Example 3, silicone powder is the main component and organosilicon resin is the auxiliary silicone-based synergistic flame retardant. Excessive silicone powder reduces the melt viscosity, affecting vertical combustion and resulting in failure to meet vertical combustion standards.

[0076] Compared with Example 1 and Comparative Example 4, without the addition of silicon-based synergistic flame retardants, the vertical combustion flame retardant requirement of V-0 can be achieved, but the lack of char formation results in poor burn-through resistance.

[0077] Compared with Example 1 and Comparative Example 5, simply replacing the organosilicon resin with an inorganic silicon-based flame retardant synergist resulted in a much lower char formation efficiency. In the 5V sample combustion test, most samples burned through within 35 to 40 seconds.

[0078] Comparing Examples 2 and 4, it is clear that using silicone resins containing reactive groups or bulky / rigid groups can improve the melt strength of the product, thereby enhancing its burn-through resistance.

[0079] Compared with Example 2 and Comparative Example 6, the silicone resin without melt strength-enhancing groups has a relatively poor effect on improving the burn-through resistance of the product. The S.2 test can meet the requirements of the same thickness but cannot meet the 5VA test requirements.

[0080] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A flame-retardant ABS resin composition resistant to burn-through, characterized in that, The components include the following parts by weight:

2. The burn-through resistant flame-retardant ABS resin composition according to claim 1, characterized in that, The ABS resin contains 20-24% acrylonitrile and 10-15% butadiene. And / or, the ABS powder is ABS with a butadiene content of more than 60%.

3. The burn-through resistant flame-retardant ABS resin composition according to claim 1, characterized in that, The flame retardant is one or more of the following: brominated triazine, brominated epoxy, decabromodiphenyl ethane, and tetrabromobisphenol A.

4. The burn-through resistant flame-retardant ABS resin composition according to claim 3, characterized in that, The flame retardant is a brominated triazine and a brominated epoxy, with a mass ratio of 6 to 7:

1.

5. The burn-through resistant flame-retardant ABS resin composition according to claim 1, characterized in that, The antimony-based flame retardant synergist is one or more of antimony trioxide, antimony pentoxide, and sodium antimonate.

6. The burn-through resistant flame-retardant ABS resin composition according to claim 1, characterized in that, The silicon-based flame retardant synergist is a modified organosilicon resin and silicone powder; The modified silicone resin is a surface-grafted silicone resin, and the surface-grafted modified groups are one of the following: long-chain branched structure, reactive group, and large-volume / rigid group.

7. The burn-through resistant flame-retardant ABS resin composition according to claim 1, characterized in that, The chlorinated polyethylene is chlorinated polyethylene with a chlorine content of 32-35%.

8. The burn-through resistant flame-retardant ABS resin composition according to claim 1, characterized in that, The antioxidant mentioned is one or more of hindered phenolic antioxidants and phosphite antioxidants; And / or, the lubricant includes one or more of fatty acid amide lubricants, stearate lubricants, fatty acid ester lubricants, and silicone lubricants; And / or, the anti-dripping agent is polytetrafluoroethylene with a molecular weight of 500,000 to 2,000,000.

9. A method for preparing the burn-through resistant flame-retardant ABS resin composition as described in claim 1, characterized in that, Includes the following steps: (1) Prepare the components according to their weight parts: (2) Mix the components in step (1) according to the above weight parts, melt extrude, cool and granulate to obtain a flame-retardant ABS resin composition that is resistant to burn-through.

10. The burn-through resistant flame-retardant ABS resin composition according to claim 9, characterized in that, The temperature during melt extrusion is 200–250℃, and the screw speed is 300–500 rpm.

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