High-fluidity high-toughness thin-wall flame-retardant PC / ABS composite material and preparation method thereof

Abstract

The invention discloses a thin-wall flame-retardant PC / ABS (polycarbonate / acrylonitrile-butadiene-styrene) composite material which comprises the following components in percentage by weight: 60-80% of polycarbonate; 5 to 25% of ABS resin; 1 to 10% of a toughening agent; 1-8% of polyphenyl ether; 5-18% of a flame retardant; and 0.5-5% of other additives. The invention also discloses a preparation method of the high-fluidity high-toughness thin-wall flame-retardant PC / ABS composite material. The PC / ABS composite material disclosed by the invention has the beneficial effects that the PC / ABS composite material can achieve the balance among various properties such as high flowability, high toughness, ultrathin halogen-free flame retardance and the like at the same time through the synergy among polyphenyl ether (PPO), the impact modifier and the flame retardant.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials, and in particular relates to a high-flow, high-toughness, thin-walled, flame-retardant PC / ABS composite material and a preparation method thereof. Background Art

[0002] Polycarbonate (PC for short) is a high molecular polymer containing carbonate groups in the molecular chain, and the most commonly used is bisphenol A type PC. Because its molecules contain a large number of benzene ring structures, the molecular chain is relatively rigid, not easy to crystallize, and has a high glass transition temperature. The molecular chain structure characteristics of PC determine that it has many excellent properties, such as balanced rigidity and toughness, good creep resistance and dimensional stability, heat resistance, transparency, low water absorption, non-toxicity, and excellent dielectric properties.

[0003] On the other hand, PC has a high melt viscosity, is notch-sensitive, and has poor resistance to organic chemicals and wear resistance. These problems can be improved by blending or copolymerization. Taking PC / ABS blending modification as an example, PC / ABS composite materials combine the advantages of PC and ABS. They have the excellent heat and weather resistance, dimensional stability and impact resistance of PC resin, and the excellent processing fluidity of ABS resin, making it widely used in many fields.

[0004] Compared with ABS materials, thin-wall halogen-free flame retardancy of PC / ABS composite materials is easier to achieve in terms of modification technology. However, there are still technical challenges in balancing its comprehensive properties (including processing fluidity, strength, toughness, thin-wall flame retardancy, heat resistance, etc.), which cannot meet the needs of various occasions. Summary of the invention

[0005] In view of the design requirements for thin-wall injection molding of PC / ABS composite materials in the field of consumer electronics and electrical appliances, the material is required to have high fluidity and thin-wall flame retardant performance, and the material toughness must be maintained at a high level. The present invention utilizes the introduction of an appropriate amount of polyphenylene ether (PPO) in the PC / ABS blending modification, and the synergy between the polyphenylene ether (PPO) and the impact modifier and the flame retardant to obtain a high-flowability, high-toughness, thin-wall flame retardant PC / ABS composite material with excellent comprehensive performance.

[0006] The purpose of the present invention is to provide a high-flow and high-toughness thin-wall flame-retardant PC / ABS composite material.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is: a high-flow and high-toughness thin-wall flame-retardant PC / ABS composite material, which is mainly made of the following components in parts by weight based on 100 parts in total: 60-80 parts of polycarbonate, 5-25 parts of ABS, 1-10 parts of toughening agent, 1-8 parts of polyphenylene ether, 5-18 parts of flame retardant, and 0.5-5 parts of other additives.

[0008] Preferably, in the composite material, the weight proportion of polycarbonate is 65-75 parts.

[0009] Preferably, in the composite material, the weight proportion of ABS is 10-25 parts.

[0010] Preferably, in the composite material, the weight portion of the toughening agent is 1-8 parts; more preferably 1-5 parts.

[0011] Preferably, in the composite material, the weight portion of polyphenylene ether is 1-6 parts.

[0012] Preferably, in the composite material, the weight portion of the flame retardant is 8-15 parts.

[0013] In the present invention, the polycarbonate comprises a homopolycarbonate having a repeating structural carbonate unit, which may be a mixture of one or both of an aliphatic polycarbonate, an alicyclic polycarbonate or an aromatic polycarbonate. In the present invention, suitable polycarbonates may be prepared by methods such as interfacial polymerization and melt polymerization. In a specific embodiment, the polycarbonate is a linear homopolymer derived from bisphenol A, i.e., a polycarbonate containing a bisphenol A structure. The weight average molecular weight of the polycarbonate measured by gel permeation chromatography is about 18,000 to about 35,000.

[0014] Preferably, the melt index of the polycarbonate is 4-25 g / 10 min at 300°C and 1.2 kg. More preferably, the polycarbonate comprises a first polycarbonate I with an MFR of 14-25 g / min and a second polycarbonate II with an MFR of 4-12 g / min at 300°C and 1.2 kg; more preferably, the weight ratio of the polycarbonate I to the polycarbonate II is 1-3:1.

[0015] In the present invention, the ABS is a copolymer of acrylonitrile-butadiene-styrene, which can be prepared by bulk polymerization, emulsion polymerization and the like.

[0016] In the present invention, the toughener includes a rubber toughener and a thermoplastic elastomer with a core-shell structure. In various embodiments, the rubber toughener with a core-shell structure is composed of a rubber-like core to which one or more shells have been grafted. The core is essentially composed of acrylate rubber or butadiene rubber, and the shell preferably comprises a vinyl aromatic compound and / or (meth) alkyl acrylate. The core and / or shell often comprise a multifunctional compound that can act as a crosslinking agent and / or a grafting agent. Preferably, the toughener is MBS (methacrylic acid-butadiene-styrene copolymer), silicone rubber (organic silicon / acrylic acid / methyl methacrylate polymer), styrene-ethylene / butylene-styrene block copolymer (SEBS), ethylene-methyl acrylate copolymer (EMA), a polyolefin elastomer (POE) and a mixture of one or two or more thereof.

[0017] Preferably, the intrinsic viscosity of the polyphenylene ether in the present invention is 0.1-0.4 dl / g.

[0018] The flame retardant is selected from oligomeric phosphates, phosphazene oligomers, polymeric phosphates, oligomeric phosphonates or mixed phosphate / phosphonate flame retardant compositions. Further, the flame retardant is selected from aromatic polyphosphate oligomers, phenoxyphosphazene oligomers, melamine polyphosphate oligomers and metal phosphinate oligomers, or a combination thereof. As further preferred, the flame retardant comprises an oligomer organophosphorus flame retardant and a phenoxyphosphazene oligomer (such as preferably hexaphenoxycyclotriphosphazene), or a combination thereof. As a specific preferred embodiment, the flame retardant is bisphenol A bis(diphenyl phosphate) (BPADP) or hexaphenoxycyclotriphosphazene or a mixture of the two.

[0019] Preferably, the other additives described in the present invention include one or more of stabilizers (heat stabilizers, antioxidants, etc.) and release agents or other additives (colorants, antistatic agents, anti-dripping agents, etc.). When present, the amount of each additive added is usually less than or equal to 2 weight percent, more specifically less than or equal to 1 weight percent of the total amount of additives used based on the total weight of the composition; the total amount of other additives is generally less than 5%. For example, the composition release agent includes, but is not limited to, tetracarboxylic acid pentaerythritol ester, monocarboxylic acid glyceride, polyolefin, silicone oil, alkyl wax and amide. The composition may also include an antioxidant stabilizer, such as a hindered phenol stabilizer, a phosphite stabilizer, a phosphonite stabilizer, or a combination comprising at least one of the aforementioned types of stabilizers.

[0020] The beneficial effects of the present invention are that the PC / ABS composite material can simultaneously achieve a balance among various properties such as high fluidity, high toughness and ultra-thin halogen-free flame retardancy.

[0021] Experimental verification shows that in the halogen-free flame-retardant PC / ABS formula system, the present invention achieves excellent levels of fluidity, toughness and thin-wall flame retardancy of the composite material through the synergy between polyphenylene ether (PPO) and impact modifier and flame retardant. DETAILED DESCRIPTION

[0022] To explain the content of the invention in more detail, the following further describes it in conjunction with specific embodiments.

[0023] The polycarbonate used in the embodiment is an aromatic polycarbonate containing a bisphenol A structure, as shown in the following formula:

[0024]

[0025] The PC used in the comparative examples and the examples is a commercially available bisphenol A polycarbonate (PC) resin product of Wanhua Chemical, and its MFR at 300° C. and 1.2 kg is 19 g / min (PC-I) and 7 g / min (PC-II), respectively.

[0026] The ABS used in the comparative examples and the examples is INEOS Styrolution GP-22, the toughening agent IM-1 used is Dow EXL-2691A, the toughening agent IM-2 used is Mitsubishi Rayon silicone-acrylic impact modifier Metablen S-2001, and the toughening agent IM-3 used is TSRC 6151SEBS.

[0027] The acrylonitrile-styrene copolymer (AS) used in the comparative example is Korean Kumho SAN320.

[0028] The polyphenylene ether (PPO) used in the comparative examples and embodiments is LXR35 from Bluestar Chemical.

[0029] The flame retardants used in the comparative examples and examples include bisphenol A bis(diphenyl phosphate) (FR-1) and hexaphenoxy cyclotriphosphazene (FR-2).

[0030] Referring to Table 1, in the comparative examples and the embodiments, the total amount of material is 10 kg, and the remaining components in the formula include antioxidants (antioxidant 1076 and / or antioxidant 168) and release agents, etc., and the added amounts are all based on the prior art (for example, the added weight ratio of antioxidant 1076 and antioxidant 168 in the embodiments and comparative examples is 1:1).

[0031] Weigh the components of polycarbonate, ABS, toughening agent, PPO, flame retardant and other additives in proportion, and put all raw materials except liquid flame retardant into high-speed mixer for high-speed premixing for 5 minutes. Add the premixed raw material mixture and liquid flame retardant into the hopper of twin-screw extruder for melting, mixing, extrusion, cooling, drying and pelletizing. The screw temperature of the twin-screw extruder is controlled between 250-270°C, the screw speed is maintained at about 300 rpm and the torque value is maintained at about 50% to about 60%, and the operation is carried out under standard processing conditions familiar to those skilled in the art. After that, the extruded pellets are air-dried at 90°C for 2 hours and then injection molded, and various performance tests are carried out. The test standards adopted are as follows:

[0032] Melt index test: ASTM D1238

[0033] Tensile properties test: ASTM D638

[0034] Bending performance test: ASTM D790

[0035] Impact performance test: ASTM D256

[0036] Thermal deformation test: ASTM D648

[0037] Flame retardant test: UL94 V0 and 5VB standards

[0038]

[0039] Table 1 Ingredients and performance test results of embodiments and comparative examples

[0040] It can be seen from the test results shown in Table 1 that in order to improve the balance of flow performance, material toughness and flame retardant performance in PC / ABS system in Comparative Examples 1-3, the method of adding toughening agent MBS and flow promoter AS is adopted, and the ratio of PC substrates with different molecular weights in the formula system is adjusted, but the results are not ideal (the flame retardant performance of the composite material is sacrificed in Comparative Example 2, and the toughness of the composite material in Comparative Example 3 is significantly reduced). In Example 1, by introducing PPO and MBS, compared with Comparative Example 1, the effect of simultaneous improvement of flow and toughness and maintaining V0 / 1.5mm flame retardant performance is preliminarily achieved. Further, by increasing the amount of flame retardant in Examples 2-4, it can be seen that the material flow and toughness can maintain a good balance in different toughening agent systems, and the flame retardant performance can reach the level of V0 / 1.2mm. Especially in Example 4, its thin-wall flame retardant can achieve the excellent performance of 5VB / 1.5mm. In Examples 5-6, as the amount of PPO increases, the flow, mechanical properties and thin-wall flame retardancy of the composite material system remain at a good level, while the notched impact strength decreases to a certain extent, but still meets the use requirements. In Example 7, the flame retardant is hexaphenoxy cyclotriphosphazene, and the notched impact strength of the material is significantly improved compared with Example 6.

Claims

1. A thin-wall flame-retardant PC / ABS composite material, characterized in that: The invention mainly comprises polycarbonate, ABS resin, toughening agent, polyphenylene ether, flame retardant and other additives, wherein the weight percentage of each component is as follows: polycarbonate: 60-80%; ABS resin: 5-25%; toughening agent: 1-10%; polyphenylene ether: 1-8%; flame retardant: 5-18%; and other additives: 0.5-5%.

2. The thin-wall flame-retardant PC / ABS composite material according to claim 1, characterized in that: The melt index of the polycarbonate is measured at 300° C. and 1.2 kg and is 4-25 g / 10 min.

3. The thin-wall flame-retardant PC / ABS composite material according to claim 1, characterized in that: The ABS resin is an acrylonitrile-butadiene-styrene copolymer, which can be prepared by bulk polymerization and emulsion polymerization.

4. The thin-wall flame-retardant PC / ABS composite material according to claim 1, characterized in that: The toughening agent is selected from rubber toughening agents with a core-shell structure and thermoplastic elastomers.

5. The thin-wall flame-retardant PC / ABS composite material according to claim 1, characterized in that: The intrinsic viscosity of the polyphenylene ether is 0.1-0.5 dl / g.

6. The thin-wall flame-retardant PC / ABS composite material according to claim 1, characterized in that: The flame retardant is an oligomer organic phosphorus flame retardant.

7. The thin-wall flame-retardant PC / ABS composite material according to claim 1, characterized in that: The other additives include one or more of a stabilizer, a release agent, a colorant, an antistatic agent, and an anti-dripping agent.

8. The thin-wall flame-retardant PC / ABS composite material according to claim 1, characterized in that: The weight percentages of the components are: polycarbonate: 65-75%; ABS resin: 10-25%; toughening agent: 1-5%; Polyphenylene ether: 1-6%; flame retardant: 8-15%; other additives: 0.5-5%.

9. The thin-wall flame-retardant PC / ABS composite material according to claim 1, characterized in that: The toughening agent is a mixture of one or more of methacrylate-butadiene-styrene copolymer, silicone rubber, styrene-ethylene / butylene-styrene block copolymer, ethylene-methyl acrylate copolymer, and polyolefin elastomer; the flame retardant is bisphenol A bis(diphenyl phosphate) or hexaphenoxy cyclotriphosphazene or a mixture of the two.

10. A method for preparing the thin-wall flame-retardant PC / ABS composite material according to any one of claims 1 to 9, characterized in that: According to the metering ratio, polycarbonate, ABS resin, toughening agent, polyphenylene ether, solid flame retardant and other additives are premixed uniformly, and liquid flame retardant is added separately. The mixture is melt-blended, extruded and granulated by an extruder to obtain a thin-wall flame-retardant PC / ABS composite material.

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