Flame-retardant PC / ABS composition as well as preparation method and application thereof

Abstract

The invention belongs to the field of plastic materials, and particularly discloses a flame-retardant PC / ABS composition as well as a preparation method and application thereof. The flame-retardant PC / ABS composition disclosed by the invention is prepared from the following components in parts by weight: 39 to 61 parts of PC, 2.5 to 11 parts of ABS, 34 to 46 parts of mica powder, 1.5 to 8.5 parts of glass fiber, 4.5 to 11 parts of a flame retardant and 0.1 to 2.1 parts of an anti-dripping agent, the mica powder comprises mica powder A and mica powder B, the mesh number of the mica powder A is 300-600, and the mesh number of the mica powder B is 20-40. The 300-600-mesh mica powder A and the 20-40-mesh mica powder B are compounded, and the two kinds of mica powder can complement each other, so that the rigidity of the composition can be effectively improved, the linear expansion coefficient and the anisotropy of the composition can be effectively reduced on the basis of keeping good flame retardance, and the flame-retardant PC / ABS composition with high rigidity and dimensional stability is comprehensively realized.

Description

Technical Field

[0001] The invention belongs to the field of plastics, and in particular relates to a flame retardant PC / ABS composition and a preparation method and application thereof. Background Art

[0002] Flame retardant PC / ABS is a commonly used plastic alloy with excellent mechanical properties, flame retardant properties, weather resistance and heat resistance, etc. It is widely used in the automotive, office, home appliance and other industries. With the development demand of thin-wall and lightweight in the industry, the industry has higher and higher performance requirements for traditional flame retardant PC / ABS alloys, such as the need to improve the rigidity of the material and the dimensional stability of the material. It is of great significance to develop flame retardant PC / ABS alloys with high rigidity and good dimensional stability.

[0003] Dimensional stability refers to the ability of a material to maintain its original size under different environmental conditions. The coefficient of linear expansion (CLTE) is an important characteristic that characterizes the dimensional stability of a material. It refers to the ratio of the change in length (ΔL) of a material within a unit temperature change (ΔT) to the initial length (L), that is, CLTE = ΔL / (L×ΔT). The anisotropy of the linear expansion coefficient refers to the difference in the linear expansion coefficient of a material in different directions, which is usually characterized by the difference in CLTE in the flow direction (MD) and the perpendicular flow direction (TD). The linear expansion coefficient and its anisotropy directly affect the dimensional stability of the material. If a material has a large linear expansion coefficient, or a large difference in linear expansion coefficient in different directions, then when the temperature changes, its parts may expand or contract at different rates, resulting in uneven changes in the overall size. This uneven change may cause the material to bend, twist, or warp, thereby reducing dimensional stability.

[0004] By adding inorganic fillers such as glass fiber, talcum powder, wollastonite, barium sulfate, magnesium sulfate whisker and nano-silica to curb the activity of molecular chains, the linear expansion coefficient of amorphous polymers can be reduced, and the rigidity of the material can be improved to a certain extent. Among them, glass fiber can significantly improve the rigidity of the material, but glass fiber is an anisotropic inorganic filler in the material, which is particularly prone to orientation effect, thereby increasing the anisotropy of the linear expansion coefficient and making it difficult to achieve dimensional stability; while fillers such as talcum powder, wollastonite, barium sulfate, magnesium sulfate whisker and nano-silica do not significantly improve the rigidity of the material and cannot meet the actual requirements for high rigidity. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of large linear expansion coefficient and anisotropy and insufficient rigidity in the flame retardant PC / ABS materials in the prior art. The present invention will provide a flame retardant PC / ABS composition and a preparation method and application thereof.

[0006] To achieve the above purpose, the following technical solutions are specifically included:

[0007] In one aspect, the present invention provides a flame retardant PC / ABS composition, comprising the following components in parts by weight:

[0008] PC 39-61 parts, ABS 2.5-11 parts, mica powder 34-46 parts, glass fiber 1.5-8.5 parts, flame retardant 4.5-11 parts, anti-dripping agent 0.1-2.1 parts; the mica powder includes mica powder A and mica powder B, the mesh number of mica powder A is 300-600 mesh, and the mesh number of mica powder B is 20-40 mesh.

[0009] Mica powder is a lamellar filler. When the average particle size of the mica lamella is small (i.e., the mesh number is large), it can better maintain the original lamella morphology during the material processing, giving the material good rigidity, but it is easy to orient along the processing flow direction with the resin matrix, resulting in a large CLTE anisotropy of the material; when the average particle size of the mica lamella is large (i.e., the mesh number is small), the lamellae are easily dissociated and wrinkled during the processing, weakening its orientation effect along the flow direction, thereby giving the material a lower linear expansion coefficient anisotropy, but it has a poor effect on improving the rigidity of the material. In addition, it effectively migrates to the combustion surface during the combustion process to participate in the carbonization degree, and it is also easy to deteriorate the flame retardant performance; the inventors of the present invention have found through repeated studies that by compounding 300-600 mesh mica powder A and 20-40 mesh mica powder B, the two mica powders can complement each other, not only the rigidity of the composition can be effectively improved, but also the linear expansion coefficient and its anisotropy can be effectively reduced, and the flame retardant performance of the composition can also reach 1.5mm spline UL94 V1 or above, a flame-retardant PC / ABS composition that achieves high rigidity, low linear expansion coefficient and anisotropy.

[0010] Preferably, the flame retardant PC / ABS composition comprises the following components in parts by weight: 40-60 parts of PC, 3-10 parts of ABS, 35-45 parts of mica powder, 2-8 parts of glass fiber, 5-10 parts of flame retardant, 0.2-2 parts of anti-dripping agent, and 0-3 parts of processing aid.

[0011] Preferably, in the flame retardant PC / ABS composition, the mass percentage of PC (polycarbonate) is not less than 30%, more preferably not less than 40%, and even more preferably not less than 45%.

[0012] The system of the present invention has no restriction on the type of PC. The polycarbonate is preferably bisphenol A polycarbonate. Homemade PC can also be used. For example, the melt mass flow rate of the polycarbonate can be 1-60 g / 10 min, wherein the melt mass flow rate is tested according to ISO 1133-1 2011 standard, and the test conditions are 300° C. and 1.2 kg. More specifically, the melt mass flow rate of the polycarbonate can be 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 g / 10 min, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0013] Preferably, the ABS is a terpolymer of acrylonitrile, butadiene and styrene. The system of the present invention has no restriction on the type of ABS, and commercially available conventional ABS can be used, or homemade ABS can be used, such as ABS having a melt mass flow rate of 1-30 g / 10 min tested at 220° C. and 10 kg in accordance with GB / T3682-2000. More specifically, the melt mass flow rate of ABS can be 1, 3, 9, 12, 15, 18, 21, 24, 27, 30 g / 10 min, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0014] In the system of the present invention, the mesh size of mica powder A is 300-600 mesh, and it is further preferred that the mesh size of mica powder A is 400-500 mesh, and specifically can be 300, 325, 350, 375, 400, 425, 450, 475, 500, 525, 550, 575, 600 mesh, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0015] Preferably, the mass percentage of iron oxide in the mica powder A and the mica powder B is 0.5-5%, which can specifically be 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0016] Preferably, the mica powder A further comprises the following components in percentage by weight: SiO 2 40%-45%, Al 2 O 3 10%-14%, K 2 O 9%-12%, Na 2O 0.3%-0.5%, MgO 30%-33%, CaO 0.1%-0.5%, TiO 2 0.1%-0.5%.

[0017] More preferably, the mica powder A further comprises the following components in percentage by weight: SiO 2 40.5%-42%, Al 2 O 3 11%-13%, K 2 O 11%-11.5%, Na 2 O 0.35%-0.4%, MgO 32%-33%, CaO 0.2%-0.3%, TiO 2 0.2%-0.25%.

[0018] Preferably, the mica powder B further comprises the following components in percentage by weight: SiO 2 50%-52%, Al 2 O 3 30%-32%, K 2 O 9%-11%, Na 2 O 0.3%-0.5%, MgO 0.5%-1%, CaO 0.8%-1%, TiO 2 0.8%-1%.

[0019] The inventors of the present invention have found that when the mass percentage of iron oxide in mica powder is 0.5-5%, the material has the characteristic of low linear expansion coefficient. When the mass percentage of iron oxide in mica powder A and mica powder B is lower than 0.5%, the linear expansion coefficient and its anisotropy increase; when the mass percentage of iron oxide in mica powder A and mica powder B is higher than 5%, the flame retardant performance will deteriorate. The mesh number and iron oxide content of mica powder are measured using conventional methods. The mesh number of the mica powder of the present invention is measured by grid screening method, and the iron oxide content can be obtained by inductively coupled plasma mass spectrometry (ICP-MS) test.

[0020] Preferably, the mass ratio of mica powder A to mica powder B is 1:(0.3-3), further preferably 1:(0.5-1), specifically 1:0.3, 1:0.5, 1:0.7, 1:0.9, 1:1.1, 1:1.3, 1:1.5, 1:1.7, 1:1.9, 1:2.1, 1:2.4, 1:2.6, 1:2.8, 1:3, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0021] Preferably, the glass fiber is a conventional round glass fiber or a flat glass fiber, and the average diameter of the glass fiber is 10-17 μm, specifically 10, 11, 12, 13, 14, 15, 16, 17 μm, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0022] Preferably, the average length of the glass fibers is 3-4.5 mm.

[0023] Preferably, the flame retardant is a phosphorus-based flame retardant, and more preferably, the flame retardant includes at least one of bisphenol A diphenyl phosphate, resorcinol diphenyl phosphate, triphenyl phosphate, and 4,4'-(isopropylidene diphenyl)bis(diphenyl phosphate).

[0024] Preferably, the anti-drip agent comprises polytetrafluoroethylene.

[0025] Preferably, the flame retardant PC / ABS composition further comprises 0.1-3.5 parts by weight of a processing aid.

[0026] Preferably, the processing aid comprises the following components in parts by weight: 0.1-1 part of antioxidant and 0.1-1 part of lubricant.

[0027] More preferably, the antioxidant is a hindered phenol antioxidant.

[0028] On the other hand, the present invention provides a method for preparing the flame retardant PC / ABS composition, comprising the following steps:

[0029] The raw materials are sequentially mixed, melted, extruded and granulated to obtain the flame retardant PC / ABS composition.

[0030] Preferably, the melting temperature is 210-250°C.

[0031] Preferably, the rotation speed during melting is 200 to 600 rpm.

[0032] The present invention also provides an application of the flame retardant PC / ABS composition in the preparation of automobile parts, office supplies, and household appliances, and can be specifically applied to the preparation of notebook computer shells and television shells.

[0033] Compared with the prior art, the present invention has the following beneficial effects: the present invention compounds 300-600 mesh mica powder A and 20-40 mesh mica powder B, and the two mica powders can complement each other, and on the basis of maintaining good flame retardant properties, the rigidity of the composition can be effectively improved, the linear expansion coefficient and its anisotropy can be effectively reduced, and a flame retardant PC / ABS composition with high rigidity and dimensional stability is comprehensively realized. DETAILED DESCRIPTION

[0034] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further described below through specific examples. The test methods used in the examples and / or comparative examples are conventional methods unless otherwise specified; the materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified. The components and raw materials used in the examples and comparative examples of the present invention are the same unless otherwise specified.

[0035] The raw material information involved in the following examples and comparative examples:

[0036] PC resin: PC 1300 10NP, LG Chemical Co., Ltd., South Korea;

[0037] ABS resin: 275, Shanghai Gaoqiao;

[0038] Mica powder A1: 300 mesh after sieving, SiO 2 :42wt.%Al 2 O 3 :13wt.%K 2 O: 11wt.%Na 2 O: 0.4wt.%, MgO: 32.7wt.%, CaO: 0.2wt.%, TiO 2 :0.2wt.%Fe 2 O 3 :0.5wt.%, Huajing Mica;

[0039] Mica powder A2: 400 mesh, Fe 2 O 3 The content is 0.5wt.%, obtained by grinding and sieving mica powder A1;

[0040] Mica powder A3: 500 mesh, Fe 2 O 3 The content is 0.5wt.%, obtained by grinding and sieving mica powder A1;

[0041] Mica powder A4: 600 mesh, Fe 2 O 3 The content is 0.5wt.%, obtained by grinding and sieving mica powder A1;

[0042] Mica powder A5: 800 mesh, Fe 2 O 3 The content is 0.5wt.%, obtained by grinding and sieving mica powder A1;

[0043] Mica powder A6: 400 mesh, SiO 2 :40.5wt.%Al2 O 3 :11.1wt.%K 2 O: 11.5wt.%Na 2 O: 0.35wt.%, MgO: 33wt.%, CaO: 0.3wt.%, TiO 2 :0.25wt.%Fe 2 O 3 : 3wt.%, Huajing mica;

[0044] Mica powder A7: 400 mesh, SiO 2 :43wt.%Al 2 O 3 :10.6wt.%K 2 O: 10wt.%Na 2 O: 0.5wt.%, MgO: 30wt.%, CaO: 0.5wt.%, TiO 2 :0.4wt.%Fe 2 O 3 : 5wt.%, Huajing mica;

[0045] Mica powder B1: 20 mesh after sieving, SiO 2 :51wt.%Al 2 O 3 :31wt.%K 2 O: 10wt.%Na 2 O: 0.4wt.%, MgO: 0.8wt.%, CaO: 0.9wt.%, TiO 2 :0.9wt.%Fe 2 O 3 : 5wt.%, Huajing mica;

[0046] Mica powder B2: 30 mesh, Fe 2 O 3 The content is 5wt.%, obtained by grinding and sieving mica powder B1;

[0047] Mica powder B3: 40 mesh, Fe 2 O 3 The content is 5wt.%, obtained by grinding and sieving mica powder B1;

[0048] Mica powder B4: 60 mesh, Fe 2 O 3 The content is 5wt.%, obtained by grinding and sieving mica powder B1;

[0049] Glass fiber 1: ECS13-4.5-534A, average diameter 13 μm, chopped into 4.5 mm, China Jushi Co., Ltd.

[0050] Glass fiber 2: ECS10-4.5-568H, average diameter 10 μm, chopped into 3 mm, China Jushi Co., Ltd.

[0051] Glass fiber 3: EDR17-2400-988A, average diameter 17 μm, chopped into 4.5 mm, China Jushi Co., Ltd.

[0052] Phosphorus flame retardant: BDP (bisphenol A-bis(diphenyl phosphate)), Wansheng;

[0053] Anti-dripping agent: polytetrafluoroethylene, commercially available;

[0054] Processing aid: Antioxidant 1010, commercially available.

[0055] Examples 1-16 and Comparative Examples 1-4

[0056] A method for preparing a flame retardant PC / ABS composition comprises the following steps:

[0057] (1) According to the amounts of raw material components in Table 1-2, each component is stirred and blended in a high-speed mixer to obtain a premix;

[0058] (2) feeding the premix into a twin-screw extruder through a main feed port, melt-mixing and extruding granulation in the twin-screw extruder to obtain the flame-retardant PC / ABS composition, wherein the screw aspect ratio is 45:1, the barrel temperature is 210-250° C., and the screw speed is 300 rpm.

[0059] The testing methods for various properties of the flame retardant PC / ABS compositions of the embodiments of the present invention and the comparative examples are as follows:

[0060] (1) Flexural modulus test: performed according to ASTM D790-2010, with a bending rate of 2 mm / min; flexural modulus > 9000 MPa is considered qualified;

[0061] (2) Flame retardant grade: The flammability test is carried out in accordance with the "Flammability Test of Plastic Materials, UL94-2019" regulations. The flame retardant grade is derived based on the burning rate, extinguishing time, ability to resist dripping, and whether the dripping is burning. The sample used for the test: 125mm long, 13mm wide, the thickness of the present invention is selected as 1.5mm during the test. According to the UL94-2019 regulations, the flame retardant grade of the material can be classified as UL94 V0, V1, V2, etc.; the flame retardant grade of V-1 or above is considered qualified;

[0062] (3) Linear expansion coefficient test: Tested according to ISO 11359-2-1999, where the flow direction (MD) is the direction of flow of the glue, and the perpendicular flow direction (TD) is the perpendicular direction of glue. The difference between the two directions CLTE-TD / MD is ≤25μm / (m.℃) and is considered qualified.

[0063] The test results are shown in Table 3.

[0064] Table 1 (parts by weight)

[0065]

[0066] Table 2 (parts by weight)

[0067]

[0068]

[0069] Table 3

[0070]

[0071] It can be seen from the above embodiments that the flame retardant PC / ABS composition of the present invention has a flexural modulus of >9000 MPa, a flame retardancy grade of V-1 or above, and a CLTE-TD / MD difference of ≤25 μm / (m.°C), and has excellent rigidity, flame retardancy and dimensional stability.

[0072] It can be seen from Example 1 and Comparative Examples 1 and 3 that when mica powder A is used alone, the bending modulus is high, but the difference in CLTE values ​​in the MD and TD directions increases significantly, and the linear expansion coefficient and its anisotropy are high; when mica powder B is used alone, the bending modulus decreases significantly and the flame retardant performance is poor; only by using a compound of mica powder A and mica powder B can the PC / ABS composition obtain good rigidity, flame retardant performance, and a lower linear expansion coefficient and its anisotropy. At the same time, in Example 2, Example 1, Example 3, and Example 4 Comparative Example 2, the mesh number of mica powder A gradually increases, the particle size of mica powder gradually decreases, and the difference between the bending modulus, flame retardant properties, and CLTE values ​​in the MD and TD directions gradually increases; in Example 5, Example 1, and Example 6 Comparative Example 4, the mesh number of mica powder B gradually increases, the particle size of mica powder gradually decreases, and the difference between the bending modulus, flame retardant properties, and CLTE values ​​in the MD and TD directions gradually increases; among them, the mesh number of mica powder A in Comparative Example 2 exceeds 600 meshes, and the mesh number of mica powder B in Comparative Example 4 exceeds 40 meshes. At this time, the particle size adaptability of mica powder A and mica powder B is poor, resulting in poor flame retardant properties of the PC / ABS composition and high linear expansion coefficient and anisotropy, and the product is obviously unqualified. It can be seen that in the present invention, only when the mesh number of mica powder A is 300-600 meshes and the mesh number of mica powder B is 20-40 meshes, the two mica powders can effectively complement and cooperate with each other to comprehensively achieve excellent rigidity, flame retardant properties and dimensional stability.

[0073] In Example 7, Example 8, Example 1, Example 9, and Example 10, the mass ratios of mica powder A to mica powder B are 1:0.3, 1:0.5, 1:0.75, 1:1, and 1:3, respectively, and the differences in bending modulus, flame retardancy, and CLTE values ​​in MD and TD directions gradually decrease. It can be seen that the mass ratio of mica powder A to mica powder B has a certain influence on rigidity, flame retardancy, and dimensional stability. In the range of 1:(0.3-3) for the mass ratio of mica powder A to mica powder B, the rigidity, flame retardancy, and dimensional stability of the PC / ABS composition are qualified. It is further preferred that the mass ratio of mica powder A to mica powder B is 1:(0.5-1), at which point the rigidity, flame retardancy, and dimensional stability of the PC / ABS composition are better.

[0074] The average diameters of the glass fibers in Example 11, Example 1 and Example 12 are 10 μm, 13 μm and 17 μm, respectively. As the average diameter of the glass fibers increases, the bending modulus gradually increases. However, the difference in CLTE in the MD and TD directions first decreases and then increases. It can be seen that the system of the present invention selects an average glass fiber diameter of 10-17 μm, which can take into account both good rigidity and dimensional stability.

[0075] The iron oxide contents of mica powder A in Example 1, Example 15 and Example 16 are 0.5wt.%, 3wt.% and 5wt.%, respectively. The rigidity of the materials is comparable. With the increase of the iron oxide content, the difference of CLTE in MD and TD directions decreases. When the iron oxide content is 0.5-5wt.%, the material can obtain better dimensional stability.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A flame retardant PC / ABS composition, characterized in that: The composition comprises the following components in parts by weight: PC 39-61 parts, ABS 2.5-11 parts, mica powder 34-46 parts, glass fiber 1.5-8.5 parts, flame retardant 4.5-11 parts, anti-dripping agent 0.1-2.1 parts; The mica powder comprises mica powder A and mica powder B, the mesh number of the mica powder A is 300-600 meshes, and the mesh number of the mica powder B is 20-40 meshes.

2. The flame retardant PC / ABS composition according to claim 1, characterized in that: The mesh size of the mica powder A is 400-500 meshes.

3. The flame retardant PC / ABS composition according to claim 1, characterized in that: The mesh size of the mica powder B is 30-35 meshes.

4. The flame retardant PC / ABS composition according to claim 1, characterized in that: The mass ratio of the mica powder A to the mica powder B is 1:(0.3-3).

5. The flame retardant PC / ABS composition according to claim 1, characterized in that: The average diameter of the glass fibers is 10-17 μm.

6. The flame retardant PC / ABS composition according to claim 1, characterized in that: The flame retardant includes at least one of bisphenol A bisdiphenyl phosphate, resorcinol bisdiphenyl phosphate, triphenyl phosphate, and 4,4'-(isopropylidene diphenyl)bis(diphenyl phosphate).

7. The flame retardant PC / ABS composition according to claim 1, characterized in that: Include at least one of the following: The anti-drip agent includes polytetrafluoroethylene; The mass percentage of iron oxide in the mica powder A and the mica powder B is 0.5-5%.

8. The flame retardant PC / ABS composition according to claim 1, characterized in that: The invention also comprises 0.1-3.5 parts by weight of a processing aid, wherein the processing aid comprises the following components in parts by weight: 0.1-1 part of an antioxidant and 0.1-1 part of a lubricant.

9. A method for preparing the flame retardant PC / ABS composition according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing, melting, extruding and granulating the raw materials in sequence to obtain the flame retardant PC / ABS composition.

10. Use of the flame retardant PC / ABS composition according to any one of claims 1 to 8 in the preparation of automotive parts, office supplies and household appliances.

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