High flow high toughness pc / abs alloy and method for making same

Abstract

The application discloses a kind of high flow high tenacity PC / ABS alloy and its preparation method;The alloy includes the following components: PC resin 60-80 parts;ABS resin 20-40 parts;Antioxidant 0.3-0.6 parts;Impact modifier 3-6 parts of compatibilization.It includes the following steps: PC, ABS, compatibilization impact modifier, antioxidant are mixed to get premix, and it is obtained by extruding granulation.The application uses polycarbonate weight average molecular weight, which ensures the tensile strength of alloy material, bending strength;Using high glue content toughener ensures the notched impact strength of alloy material, and suitable shell structure increases the compatibility of PC / ABS.The preparation method of the application is simple and easy to operate, and easy to industrial production;The product prepared by the method can be widely used in high tenacity and high flow demand material field, and has very broad application prospect and industrial value.

Description

Technical Field

[0001] This invention belongs to the field of polymer modification technology, and in particular relates to a high-flow, high-strength and high-toughness PC / ABS alloy and its preparation method. Background Technology

[0002] With the development of industries such as automobiles and electronic materials, the increasing demand for thinner-walled, lighter-weight products and improved production efficiency requires polymer materials to possess not only high strength and other mechanical properties, but also better processing flowability. Polycarbonate (PC) is a thermoplastic engineering plastic with excellent physical and mechanical properties, excellent dimensional stability, a wide operating temperature range, and good transparency and flame retardancy. However, due to the high rigidity of the polycarbonate molecular chain, high notch sensitivity, and high melt viscosity, processing and molding are difficult, especially for large parts, which are prone to stress cracking, thus limiting its application range to some extent. Generally, it is modified and blended with ABS resin and MBS resin. Although the addition of ABS can improve the flowability of the composition, the improvement is limited and it is difficult to meet the flowability requirements for thinner-walled products. Although the addition of MBS toughening agent can improve notch impact sensitivity, the flowability is significantly reduced.

[0003] Literature and other patents also mention that various lubricants can be added to improve the fluidity of PC / ABS. However, lubricants are generally low-grade aliphatic hydrocarbons or low-molecular-weight silicone oils. These low-melting-point substances are mixed into the polymer to play a physical lubricating role. If too little low-molecular-weight substance is added, the improvement effect is not obvious, and if too much is added, the mechanical properties will decrease significantly.

[0004] The melt flow rate (MI value) of commonly used high-end PC / ABS materials in China is usually below 18 g / 10 min (260℃, 5 kg), which easily leads to poor flow, injection molding difficulties, and high defect rates. Therefore, it is necessary to further improve the processing flowability of high-strength and tough PC / ABS. Summary of the Invention

[0005] The technical problem to be solved by the present invention is the low processing fluidity of high-strength and high-toughness PC / ABS alloys in the prior art. The present invention provides a high-flow, high-strength and high-toughness PC / ABS alloy and its preparation method, which significantly improves the fluidity of the material without sacrificing the mechanical properties of the material.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] This invention provides a high-flow, high-strength, and high-toughness PC / ABS alloy, comprising the following raw materials in parts by weight:

[0008]

[0009] The compatibilizing and impact-resistant modifier is an acrylic monomer grafted onto rubber particles, with the acrylic monomer grafting content ranging from 0.5 to 1.5 wt%.

[0010] As one embodiment of the present invention, the weight-average molecular weight of the PC resin is 30,000-60,000.

[0011] As one embodiment of the present invention, the ABS resin is selected from emulsion ABS or bulk ABS.

[0012] As one embodiment of the present invention, the antioxidant is selected as a primary antioxidant or a combination of a primary antioxidant and a phosphite-based auxiliary antioxidant.

[0013] As one embodiment of the present invention, the rubber particles grafted with acrylic monomers are prepared by a method including the following steps: rubber particle powder, acrylic monomers, surfactants, peroxide initiators, suspending dispersants and water are suspended and polymerized at high temperature for 3-6 hours to obtain a crude product; the product is then filtered, washed and dried.

[0014] As one embodiment of the present invention, the rubber particles are core-shell toughening agents with butadiene as the core and styrene and acrylonitrile polymer as the shell, or methyl methacrylate and styrene as the shell.

[0015] In one embodiment of the present invention, the particle size of the rubber particles is 100-400 micrometers. If the particle size is too large, the contact surface area is small, resulting in low reaction efficiency; therefore, 100-400 micrometers is selected.

[0016] As one embodiment of the present invention, in order to maintain toughening efficiency, the butadiene core content in the rubber particles is 60wt%-75wt%.

[0017] In one embodiment of the present invention, the acrylic monomer is an acrylic monomer or a methacrylic monomer.

[0018] As one embodiment of the present invention, the surfactant is selected from toluene, ethylbenzene, methyl methacrylate, and methyl acrylate monomers.

[0019] As one embodiment of the present invention, the peroxide initiator is selected from benzoyl peroxide, benzoyl tert-butyl peroxide, and methyl ethyl ketone peroxide.

[0020] As one embodiment of the present invention, the suspending dispersant is selected from sodium alkylbenzene sulfonate, polyvinyl alcohol, and calcium hydroxyphosphate.

[0021] In one embodiment of the present invention, the total amount of the rubber granule powder, acrylic monomer, surfactant, peroxide initiator, and suspending dispersant, and the mass ratio of water are 1:1-3. The mass ratio of the rubber granule powder, acrylic monomer, surfactant, peroxide initiator, and suspending dispersant is 100:0.5-2.0:0.5-5:0.1-0.5:0.8-3.

[0022] The present invention also relates to a method for preparing a high-flow, high-strength and high-toughness PC / ABS alloy, the method comprising the following steps: mixing PC, ABS, compatibilizing and impact-resistant modifier, and antioxidant in a high-speed mixer for 2-10 minutes to obtain a premix; and placing the premix into a twin-screw extruder for extrusion granulation to obtain the final product.

[0023] As one embodiment of the present invention, the extrusion process of the twin-screw extruder is as follows: the temperature of the feeding section is 220-250℃, the temperature of the plasticizing section is 240-260℃, the temperature of the homogenizing section is 240-260℃, and the screw speed is 300-600rpm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The polycarbonate used in this invention has a high weight-average molecular weight, which ensures the tensile and flexural strength of the alloy material; the toughening agent with high glue content ensures the notched impact strength of the alloy material, and the appropriate shell structure increases the compatibility of PC / ABS.

[0026] 2) This invention uses a suspension grafting method to synthesize rubber particles grafted with acrylic acid. On the one hand, it promotes the uniform distribution of acrylic acid on the surface of the rubber particles, solving the problem of uneven distribution due to incompatibility between acrylic acid and the matrix resin. On the other hand, grafting acrylic acid introduces carboxyl functional groups on the surface of the rubber particles, which promotes the formation of weak charge forces between the rubber surface and the polycarbonate matrix resin, thereby improving fluidity.

[0027] 3) The preparation method of the present invention is simple and easy to implement, and is easy to industrialize; the products prepared by this method can be widely used in the field of materials with high strength and toughness and high flow requirements, and have a very broad application prospect and industrial value. Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific 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 various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0029] The preparation method is as follows:

[0030] Step 1: Preparation of compatibilizing and impact modifier M05 (rubber particles grafted with acrylic acid, acrylic acid grafting rate 0.5wt%): KANE ACE M-732 rubber particle powder (100 parts), methacrylic acid monomer (0.5 parts), methyl methacrylate (2 parts), benzoyl peroxide (0.3 parts), polyvinyl alcohol (2 parts) and water (300 parts) are suspended and polymerized at high temperature for 3-6 hours to obtain crude product; filtered, washed and dried to obtain the final product.

[0031] Step 2: Preparation of compatibilizing and impact modifier M15 (rubber particles grafted with acrylic acid, acrylic acid grafting rate 1.5wt%): KANE ACE M-732 rubber particle powder (100 parts), methacrylic acid monomer (1.5 parts), methyl methacrylate (1 part), benzoyl peroxide (0.4 parts), polyvinyl alcohol (2 parts) and water (300 parts) are suspended and polymerized at high temperature for 3-6 hours to obtain crude product; filtered, washed and dried to obtain the final product.

[0032] Step 3: Mix PC resin, ABS resin, compatibilizer and impact modifier M05 (rubber granules grafted with acrylic acid, acrylic acid grafting rate 0.5wt%), compatibilizer and impact modifier M15 (rubber granules grafted with acrylic acid, acrylic acid grafting rate 1.5wt%), and antioxidant (168 / 1010) in a high-speed mixer for 2-10 minutes to obtain a premix. Place the premix into a twin-screw extruder and extrude to granulate. The extrusion process using a co-rotating twin-screw extruder in this scheme is as follows: feed section temperature 220-250℃, plasticizing section temperature 240-260℃, homogenizing section temperature 240-260℃, and screw speed 300-600 rpm.

[0033] The composition and formulation of the PC / ABS mixed resins in Comparative Examples 1-3 and Examples 1-4 are shown in Table 1.

[0034] Table 1. Formulation ratios (by weight) for Comparative Examples 1-3 and Examples 1-4

[0035]

[0036] The physical and mechanical properties of Examples 1-4 and Comparative Examples 1-3 described above were tested according to the following standards: tensile strength: ASTM D638; flexural strength: ASTM D790; flexural modulus: ASTM D790; notched impact resistance: ASTM D256; melt flow index: ASTM D1238. The test results are shown in Table 2.

[0037] Table 2. Comparison of flowability and mechanical properties between the examples and comparative examples

[0038]

[0039] Table 2 shows that Comparative Example 1, being a blank example, although having a melt flow index of 19.4 and decent flowability, exhibited poor mechanical properties in the composite material, particularly the 1 / 4 notched impact strength. PC / ABS materials are characterized by notch sensitivity, manifested in poor 1 / 4 notched impact strength; therefore, 1 / 4 notched impact strength is crucial for PC / ABS materials. The main reason for the poor overall performance of Comparative Example 1 is that while the macroscopic granulation and strip formation of PC and ABS materials is acceptable, the microscopic ABS dispersed phase is unstable. During injection molding, the PC / ABS material undergoes secondary shearing, resulting in poor overall performance.

[0040] Comparative Examples 2-3 show that after adding MBS toughening agent, MBS plays a role in compatibilizing and toughening PC / ABS, but its melt indexes are 12.5 and 9.3 respectively, which is a very normal result. Generally, toughening agents contain a micro-crosslinked core structure, so the fluidity will decrease after adding toughening agent, and the fluidity will decrease more severely with the increase of toughening agent addition.

[0041] The results of Examples 1-4 show that after adding M05 and M15 rubber-grafted acrylic compatibilizers and toughening modifiers, the mechanical properties, including tensile strength, flexural strength, and impact strength, are maintained very well, especially the 1 / 4 notched impact strength, which remains above 450 J / m. The melt flow index is above 20 g / 10 min for both. With increasing M05 content, the impact performance decreases slightly, but the melt flow index continues to increase. Comparing M05 and M15, a higher acrylic grafting rate results in a greater improvement in flowability.

[0042] 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 high flow high toughness PC / ABS alloy composition characterized in that, The weight parts of each raw material include: PC resin 60-80 parts, ABS resin 20-40 parts, Antioxidant 0.3-0.6 parts, Impact modifier 3-6 parts; The impact modifier is rubber particle grafted acrylic monomer, the grafted content of acrylic monomer is 0.5-1.5 wt%; the rubber particle is core-shell structure toughener with butadiene as core and styrene-acrylonitrile polymer as shell or methyl methacrylate-styrene as shell; the acrylic monomer is acrylic monomer or methacrylic monomer.

2. The high flow high toughness PC / ABS alloy composition according to claim 1, characterized in that, The weight average molecular weight of the PC resin is 30000-60000.

3. The high flow high toughness PC / ABS alloy composition of claim 1, wherein, The ABS resin is selected from emulsion ABS or bulk ABS.

4. The high flow high toughness PC / ABS alloy composition of claim 1, wherein, The antioxidant is selected from primary antioxidant or the combination of primary antioxidant and phosphite auxiliary antioxidant.

5. The high flow high toughness PC / ABS alloy composition of claim 1, wherein, The rubber particle grafted acrylic monomer is prepared by the method including the following steps: suspending polymerization of rubber particle powder, acrylic monomer, interface active agent, peroxide initiator, suspending dispersant and water at high temperature for 3-6 hours to obtain crude product; filtering, washing and drying to obtain the rubber particle grafted acrylic monomer.

6. The high flow high toughness PC / ABS alloy composition according to claim 5, characterized in that, The particle size of the rubber particle is 100-400 microns, and the content of butadiene core in the rubber particle is 60 wt%-75 wt%.

7. The high flow high toughness PC / ABS alloy composition of claim 5, wherein, The interface active agent is selected from toluene, ethylbenzene, methyl methacrylate and methyl acrylate monomer; the peroxide initiator is selected from benzoyl peroxide, tert-butyl benzoyl peroxide and methyl ethyl ketone peroxide; and the suspending dispersant is selected from sodium alkyl benzene sulfonate, polyvinyl alcohol and hydroxy calcium phosphate.

8. The high flow high toughness PC / ABS alloy composition of claim 5, wherein, The mass ratio of the total amount of rubber particle powder, acrylic monomer, interface active agent, peroxide initiator and suspending dispersant to water is 1:1-3; the mass ratio of rubber particle powder, acrylic monomer, interface active agent, peroxide initiator and suspending dispersant is 100:0.5-2.0:0.5-5:0.1-0.5:0.8-3.

9. A process for the preparation of the high flow high toughness PC / ABS alloy according to any one of claims 1 to 8, characterized in that, The method includes the following steps: mixing PC, ABS, impact modifier and antioxidant in a high-speed mixer for 2-10 minutes to obtain premix; and putting the premix into a double screw extruder to extrude and granulate to obtain the product.

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