High-flowability low-internal-stress halogen-free flame-retardant wear-resistant PC / ABS material and preparation method thereof

Abstract

The invention discloses a high-flowability low-internal-stress halogen-free flame-retardant wear-resistant PCABS material and a preparation method thereof. The high-flowability low-internal-stress halogen-free flame-retardant wear-resistant PCABS material comprises the following components in parts by weight: 50-70 parts of PC resin, 5-10 parts of ABS resin, 15-25 parts of a flame retardant, 20-35 parts of a flexibilizer, 0.1-0.5 part of an antioxidant A, 0.1-0.5 part of an antioxidant B, 0.3-1 part of an anti-dripping agent, 0.3-1 part of a lubricant, 0.3-1 part of polytrifluoropropylmethylsiloxane and 0.1-0.3 part of porous graphite. The PC / ABS material prepared by the invention has excellent flowing property and smaller internal stress, can be used for small parts such as mobile phones, and can also be used for shells of large parts such as household appliances, automobile lamp systems, grids and the like; the problem that the PC / ABS alloy cracks due to stress is solved to a great extent, and the improvement of the product percent of pass is greatly facilitated. The preparation process of the high-flowability low-internal-stress halogen-free flame-retardant wear-resistant PC / ABS material provided by the invention is relatively simple, and stable batch production can be carried out.

Description

Technical Field

[0001] The invention relates to the technical field of material preparation, in particular to a high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material and a preparation method thereof. Background Art

[0002] Polycarbonate (PC) is an engineering plastic with excellent performance, but it has disadvantages such as poor processing fluidity, easy internal stress cracking, sensitivity to notches, easy wear, poor chemical resistance, and high price. This is determined by its molecular structure. The internal stress of the product is large. There are benzene rings in the molecular structure of polycarbonate, which makes it difficult to orient. After molding, the oriented chain links tend to return to their natural state, but because the molecular chain links have been frozen and the forces between the molecular chains, stress may exist in the product. The problem of stress cracking seriously affects the application range of the material, limiting its application in many fields.

[0003] The performance of acrylonitrile-butadiene-styrene (ABS) is between that of engineering plastics and general-purpose plastics, but it has poor flame retardancy and produces a large amount of black smoke when burned. PC / ABS alloy materials are widely used due to their good physical and chemical properties. However, in the shells of some large household appliances, the flow processing properties and resistance to internal stress cracking of commonly used PC / ABS materials cannot meet the use requirements. For example, large-scale shell electronic and electrical products such as automobile grilles, TV shells, and printer shells have certain requirements for their flow processing properties and cracking resistance due to their part size and structure; due to their use environment, they require strong resistance to chemical reagents. At the same time, the shell components also have certain requirements for the appearance and performance of their products. In order to meet the safe use requirements of PC / ABS alloys in practical applications, research on halogen-free and environmentally friendly high-flow and low-internal stress PC / ABS alloy materials has become the focus of the materials field. Summary of the invention

[0004] In order to overcome the above problems existing in the prior art, the present invention provides a high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material and a preparation method thereof.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, wherein the specific components include the following parts by weight: 50-70 parts by weight of PC resin, 5-10 parts by weight of ABS resin, 15-25 parts by weight of flame retardant, 20-35 parts by weight of toughening agent, 0.1-0.5 parts by weight of antioxidant A, 0.1-0.5 parts by weight of antioxidant B, 0.3-1 parts by weight of anti-dripping agent, 0.3-1 parts by weight of lubricant, 0.3-1 parts by weight of polytrifluoropropylmethylsiloxane, and 0.1-0.3 parts by weight of porous graphite; The polytrifluoropropylmethylsiloxane is prepared by the following method: Step A, D3 F Monomer purification; Step B, placing the Shrek tube and the single-necked flask in a hot air drying oven to dry, and then placing them in a glove box to evacuate, weighing the phosphazene salt catalyst, placing it in the Shrek tube, and dissolving it with a tetrahydrofuran solution; Step C, D3 purified by step A F The monomer is placed in a single-necked flask and mixed thoroughly with the tetrahydrofuran solution; Step D, transfer the solution obtained in step C to the Shrek tube in step B, stir at room temperature and transfer to a 30°C oil bath to wait for the reaction to be completed, add a drop of glacial acetic acid to terminate the polymerization, and introduce methanol solution for precipitation to obtain a crude polymer product; Step E, dissolving the crude product of step D in tetrahydrofuran, slowly adding methanol to precipitate the polymer after it is completely dissolved, separating the polymer by centrifugation, washing with methanol and drying to obtain polytrifluoropropylmethylsiloxane.

[0006] The above-mentioned high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material has a PC resin melt flow rate of 10-20 g / 10 min at 300° C.*1.2 kg and a molecular weight of 30,000-50,000.

[0007] The above-mentioned high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, wherein the ABS resin is an acrylonitrile-butadiene-styrene copolymer with a molecular weight of 80,000 to 150,000, and the mass percentage content of each component thereof is 10% to 30% acrylonitrile, 15% to 30% butadiene, and 40% to 70% styrene.

[0008] In the above-mentioned high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, the toughening agent is a copolymerized methyl methacrylate-butadiene-styrene (MBS) core-shell type impact modifier.

[0009] The above-mentioned high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, wherein the antioxidant is one or more of hindered phenol and phosphate antioxidants; the flame retardant is a condensation-type halogen-free phosphate flame retardant; and the lubricant is one or more of silicone masterbatch and alcohol ester lubricants.

[0010] A method for preparing a high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, which is used to prepare the above-mentioned high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, specifically comprising: Step 1, weigh the raw materials according to the ratio; dry in a forced air oven at 100°C for 3-4 hours.

[0011] Step 2, the dried raw materials are mixed and continuously and evenly added into the main barrel of the twin-screw extruder. The temperature of the main barrel is controlled in sections. The speed of the twin screw is 500 rpm. The extruded material strips are cooled in a water tank and then pelletized to obtain the product.

[0012] In the above-mentioned method for preparing a high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, the screw diameter of the twin-screw extruder is 35 mm, and the aspect ratio L / D=40.

[0013] The above-mentioned method for preparing a high-flow, low-internal stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, wherein the main barrel has a temperature of 250°C, 270°C, 270°C, 270°C, 270°C, 270°C, and 270°C from the feeding port to the die outlet.

[0014] The beneficial effect of the present invention is that the PC / ABS material prepared by the present invention has excellent flow properties and small internal stress, and can be used for small parts such as mobile phones, and can also be used for large parts such as home appliances, automobile lighting systems, grilles, etc. The material greatly improves the problem of stress cracking of PC / ABS alloys, which is of great help to improve the qualified rate of products. The preparation process of the high-flow, low-internal stress halogen-free flame-retardant and wear-resistant PC / ABS material proposed by the present invention is relatively simple, and stable mass production can be carried out. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with specific implementation methods.

[0016] The present embodiment discloses a high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, wherein the specific components include the following components in parts by weight: 50-70 parts by weight of PC resin, 5-10 parts by weight of ABS resin, 15-25 parts by weight of flame retardant, 20-35 parts by weight of toughening agent, 0.1-0.5 parts by weight of antioxidant A, 0.1-0.5 parts by weight of antioxidant B, 0.3-1 parts by weight of anti-dripping agent, 0.3-1 parts by weight of lubricant, 0.3-1 parts by weight of polytrifluoropropylmethylsiloxane, and 0.1-0.3 parts by weight of porous graphite.

[0017] Polytrifluoropropylmethylsiloxane is a self-made additive, and the specific preparation method includes: Step A, purification of monomers D3 F When preparing polytrifluoropropylmethylsiloxane through anionic ring-opening polymerization, a small amount of impurities in the raw materials may cause the deactivation of the anionic initiator and the change of the polymer molecular weight. Therefore, the polymerization reaction has high requirements for the purity of the monomer and needs to be refined. FThe monomer is purified by heating and reduced pressure distillation, and the fraction at 130-135° C. is cut under a pressure of 20 mmHg.

[0018] Catalyst selection: phosphazene base salt catalyst Step B, Preparation of polytrifluoropropylmethylsiloxane Prepare a 50 mL Shrek tube and a 50 mL single-necked flask in advance. Place a magnetic rod of appropriate size in the Shrek tube, and then place it in a hot air drying oven at 120°C and dry for more than 1 hour. While they are still hot, place them in the small inlet and outlet chamber of the glove box and evacuate for more than 30 minutes, then enter the glove box and take the reaction bottle in. Measure 1 mL of the tetrahydrofuran solution of the catalyst (0.05 mol / L) and place it in the Shrek tube. Weigh D3 F The monomers were put into a single-necked flask, and then tetrahydrofuran was measured and put into the single-necked flask to be fully mixed with the monomers. Then they were transferred into a Shrek tube containing a tetrahydrofuran solution containing a phosphazene salt catalyst, stirred at room temperature for 2 min, and transferred to a 30°C oil bath pot to wait for the reaction to be completed. A drop of glacial acetic acid was added to terminate the polymerization, and a methanol solution was poured in for precipitation to obtain a crude polymer product.

[0019] Step C, purification of the polymer product: The polymer was dissolved in an appropriate amount of tetrahydrofuran, and after it was completely dissolved, methanol was slowly added to precipitate the polymer. The polymer was separated by centrifugation, washed three times with methanol, and the product was dried in a vacuum drying oven to obtain the polymer.

[0020] The melt flow rate of PC resin is 10-20g / 10min at 300℃*1.2kg; the molecular weight is between 30000-50000.

[0021] ABS resin is an acrylonitrile-butadiene-styrene copolymer with a molecular weight of 80,000 to 150,000, and the mass percentage content of its components is 10% to 30% acrylonitrile, 15% to 30% butadiene, and 40% to 70% styrene.

[0022] The toughening agent is a copolymerized methyl methacrylate-butadiene-styrene (MBS) core-shell type impact modifier. The antioxidant is one or more of hindered phenol and phosphate antioxidants; the flame retardant is a polycondensation type halogen-free phosphate flame retardant; and the lubricant is one or more of silicone masterbatch and alcohol ester lubricants.

[0023] This embodiment also discloses a method for preparing the above-mentioned material, and the specific steps are as follows: 1) Weigh the raw materials according to the ratio; 2) After mixing the dried raw materials, continuously and evenly add them into the main barrel of a twin-screw extruder with a twin-screw feeder. The screw diameter is 35 mm and the aspect ratio L / D is 40. The temperature of the main barrel is controlled in sections, and the temperature from the feeding port to the die outlet is 250° C., 260° C., 260° C., 270° C., 270° C., 270° C., 270° C., and 270° C. The twin-screw speed is 500 rpm. The extruded material strips are cooled in a water tank and then pelletized to obtain the product.

[0024] Based on the above formula and preparation method, the specific models of the raw materials used in this embodiment are: PC resin: produced by Lotte, South Korea, HOPELEX PC-1220; ABS resin: produced by Takahashi Petrochemical; MBS toughening agent: Japan's Kanebashi, model 724, copolymerized methyl methacrylate-butadiene-styrene (MBS) core-shell type impact modifier; antioxidant 1076: hindered phenol antioxidant, produced by DOUBLE BOND CHEMICAL IND. Co., Ltd.; antioxidant AO 3600: phosphite auxiliary antioxidant; flame retardant PX220: condensation type halogen-free phosphate flame retardant, polyaryl phosphate (PX-220), Zhejiang Wansheng Co., Ltd.; lubricant: silicone masterbatch.

[0025] The above-mentioned raw materials are used in different proportions to prepare PC / ABS materials. The specific formula is shown in Table 1.

[0026] Table 1 Material formula of Examples 1-6 (weight %) .

[0027] The particle material prepared according to the method disclosed in this embodiment is dried in a blast oven at 100-120° C. for 3-5 hours, and then the dried particle material is injection molded on an injection molding machine to prepare a sample.

[0028] The above products were dried in a drying oven at 100°C for 4 hours, and injection molded into ASTM standard specimens using a plastic injection molding machine at an injection molding temperature of 255°C; the performance of the injection-molded specimens was tested after being placed at a relative humidity of 50% and 23°C for 24 hours.

[0029] Melt flow rate test: according to ASTM D1238 standard, plastic particles, 260℃*2.16kg.

[0030] Tensile strength test: carried out according to ASTM D638 standard.

[0031] Bending strength test: carried out according to ASTM D790 standard.

[0032] Notched impact strength test: carried out according to ASTM D256 standard.

[0033] Internal stress test: observe the cracking of the nut by placing the injection molded stud in a 60℃ oven. The surface cracking within a certain period of time can be used to evaluate the internal stress; the faster and more cracks appear, the greater the stress; the deeper the cracks, the greater the stress.

[0034] The flow properties of the material are judged by the melt flow rate value obtained from the test.

[0035] The mechanical properties of the material are judged by the values ​​of tensile strength, flexural strength and notched impact strength obtained from the tests.

[0036] The thermal properties of the material are judged by the measured heat deformation temperature.

[0037] Internal stress test: judged by measuring the surface crack state of the sample.

[0038] According to the above standards, performance tests were performed on Examples 1-6, and the test results are shown in Table 2.

[0039] Table 2 Test results of Examples 1 to 6

[0040] By comparing the test results of Examples 1, 2, and 3, it can be seen that with the increase in the content of polytrifluoropropylmethylsiloxane, the performance of the material does not change much, and the internal stress of the material 2 and 3 is excellent. By comparing the test results of Examples 1, 2, and 4, it can be seen that the addition of polytrifluoropropylmethylsiloxane can improve the internal stress of the material to a certain extent. By comparing the test results of Example 3 and Example 1, it can be seen that the addition of lubricant can significantly improve the internal stress state of the material and reduce the internal stress of the workpiece. By comparing the crack phenomenon of Example 1 and Examples 2 and 3, it can be seen that the mutual use of lubricants is more effective and has a significant effect on improving the internal stress of the material.

[0041] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, characterized in that: specific ingredients The invention comprises the following parts by weight: 50-70 parts by weight of PC resin, 5-10 parts by weight of ABS resin, 15-25 parts by weight of flame retardant, 20-35 parts by weight of toughening agent, 0.1-0.5 parts by weight of antioxidant A, 0.1-0.5 parts by weight of antioxidant B, 0.3-1 parts by weight of anti-dripping agent, 0.3-1 parts by weight of lubricant, 0.3-1 parts by weight of polytrifluoropropylmethylsiloxane, and 0.1-0.3 parts by weight of porous graphite; The polytrifluoropropylmethylsiloxane is prepared by the following method: Step A, D3 F Monomer purification; Step B, placing the Shrek tube and the single-necked flask in a hot air drying oven to dry, and then placing them in a glove box to evacuate, weighing the phosphazene salt catalyst, placing it in the Shrek tube, and dissolving it with a tetrahydrofuran solution; Step C, D3 purified by step A F The monomer is placed in a single-necked flask and mixed thoroughly with the tetrahydrofuran solution; Step D, transfer the solution obtained in step C to the Shrek tube in step B, stir at room temperature and transfer to a 30°C oil bath to wait for the reaction to be completed, add a drop of glacial acetic acid to terminate the polymerization, and introduce methanol solution for precipitation to obtain a crude polymer product; Step E, dissolving the crude product of step D in tetrahydrofuran, slowly adding methanol to precipitate the polymer after the crude product is completely dissolved, separating the polymer by centrifugation, washing with methanol and drying to obtain polytrifluoropropylmethylsiloxane.

2. The high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material according to claim 1, characterized in that: The PC resin has a melt flow rate of 10-20 g / 10 min at 300° C.*1.2 kg, and a molecular weight of 30,000-50,000.

3. The high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material according to claim 1, characterized in that: The ABS resin is an acrylonitrile-butadiene-styrene copolymer with a molecular weight of 80,000 to 150,000, and the mass percentage content of each component thereof is 10% to 30% acrylonitrile, 15% to 30% butadiene, and 40% to 70% styrene.

4. The high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material according to claim 1, characterized in that: The toughening agent is a copolymerized methyl methacrylate-butadiene-styrene (MBS) core-shell type impact modifier.

5. The high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material according to claim 1, characterized in that: The antioxidant is one or more of hindered phenol and phosphate antioxidants; the flame retardant is a polycondensation type halogen-free phosphate flame retardant; and the lubricant is one or more of silicone masterbatch and alcohol ester lubricants.

6. A method for preparing a high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material, characterized in that: Used to prepare the high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material as claimed in any one of claims 1 to 5, specifically comprising: Step 1, weigh the raw materials according to the ratio; dry in a forced air oven at 100°C for 3-4 hours.

7. Step 2, after the dried raw materials are mixed, they are continuously and evenly added into the main barrel of the twin-screw extruder. The temperature of the main barrel is controlled in sections. The speed of the twin screw is 500 rpm. The extruded material strips are cooled in a water tank and then pelletized to obtain the product.

8. The method for preparing a high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material according to claim 6, characterized in that: The screw diameter of the twin-screw extruder is 35 mm, and the aspect ratio L / D=40.

9. The method for preparing a high-flow, low-internal-stress, halogen-free, flame-retardant, and wear-resistant PC / ABS material according to claim 6, characterized in that: The main barrel has a temperature of 250°C, 270°C, 270°C, 270°C, 270°C, 270°C, and 270°C from the feeding port to the head outlet.

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