Nanocompatible polypropylene-polystyrene composition and its manufacturing method

Abstract

The present invention relates to a nano-compatible polypropylene-polystyrene composition and a method for preparing the same. The weight components of the composition are 60-80 parts of polypropylene resin, 20-40 parts of modified polystyrene nanofiber nonwoven fabric, 0.1-1 part of antioxidant, and 0.1-1 part of lubricant. The polypropylene resin, antioxidant, and lubricant are added to a mixer and mixed well, and then fed into the main feed of a screw machine, and the modified polystyrene nanofiber nonwoven fabric is added to the side feed port of the 8th zone by weight loss control at the same time. The melt extrusion is carried out at an extrusion temperature of 180-210°C and a screw speed of 200-500 rpm, and then cooled and granulated to obtain a nano-compatible polypropylene-polystyrene composition. Compared with the existing technology, the present invention can effectively improve the compatibility of polystyrene and polypropylene, and the obtained polystyrene / polypropylene resin composition has excellent toughness, chemical resistance, high strength, is easy to manufacture, has low material cost, and can make up for the performance deficiencies of polystyrene and polypropylene.

Description

[Technical field]

[0001] The present invention relates to the technical field of polymeric materials, in particular to a nanocompatible polypropylene-polystyrene composition and a method for preparing the same. [Background technology]

[0002] Polypropylene materials are widely used in the fields of plastics and films because the raw materials are simple and low cost. However, polypropylene materials have low steric hindrance of the molecular chain, so although it has good toughness, it has low mechanical strength and poor rigidity. In addition, this material is prone to crystallization and has a large shrinkage rate, so it has poor dimensional stability during the injection molding process and is prone to deformation, which greatly limits its scope of use. Polystyrene (PS) is a polymer material obtained by free radical polymerization of styrene, and has high rigidity, high transparency and low impact properties due to the steric hindrance of the benzene ring in the side chain. Similarly, its raw materials are easy to obtain and low cost, so it is widely used in the field of plastics. Therefore, it is very necessary to make these two materials into alloy materials in order to combine the advantages of these two materials and obtain a material that is comprehensively excellent in terms of high toughness, high rigidity and low shrinkage. However, the solubility parameters of polyolefin and polystyrene are significantly different, which results in poor compatibility.

[0003] The traditional compatibilization method is to add a compatibilizer to both. For example, the Chinese invention patent application with publication number CN108276657A discloses using PP-g-maleic anhydride as a compatibilizer, directly blending with polypropylene and polystyrene, and then melt extruding. However, this direct blending method often requires the addition of a large amount of compatibilizer, which significantly increases the production cost. At the same time, the compatibilizer cannot be reliably located in the middle of the polypropylene phase and the polystyrene phase, and therefore good compatibility effect cannot be obtained. The Chinese invention patent application with publication number CN102643484B discloses an in-situ compatibilized polyolefin / polystyrene alloy and its preparation method and application. This technology is to directly add the compatibilization starting mother liquor consisting of the crosslinking agent, co-crosslinking agent and oily carrier to the polyolefin and polystyrene to achieve the purpose of compatibilizing the polyolefin and polystyrene. However, if the mother liquor is directly added to the mixture, it is not easy to disperse the mother liquor evenly in the substrate, and aggregation is likely to occur, which may result in localized excessive cross-linking and affect the physical properties, which may reduce the compatibilization efficiency and make the process difficult to control.

[0004] Currently, there is no efficient, low-cost, and controllable method for compatibilizing polypropylene and polystyrene to prepare high-performance polypropylene-polystyrene compositions. Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide a nano-compatible polypropylene-polystyrene composition for improving the compatibility between polystyrene and polypropylene, and a method for preparing the same. [Means for solving the problem]

[0006] The object of the present invention can be achieved by the following technical solution: a nanocompatible polypropylene-polystyrene composition, comprising the following components by weight: 60-80 parts polypropylene resin, 20-40 parts modified polystyrene nanofiber nonwoven fabric, 0.1-1 part antioxidant, and 0.1-1 part lubricant.

[0007] The modified polystyrene nanofiber nonwoven fabric is preferably a nanofiber nonwoven fabric having a fiber diameter in the range of 100 to 600 nm, which is obtained by electrospinning a polystyrene resin and a PP-g-MAH composition.

[0008] More preferably, the polystyrene resin and the PP-g-MAH composition are mixed in a DMF solution, and a nanofiber nonwoven fabric is obtained by electrospinning.

[0009] More preferably, the polystyrene resin and PP-g-MAH composition comprises the following components by weight: 98-99 parts polystyrene resin and 1-2 parts PP-g-MAH.

[0010] More preferably, the method for producing a modified polystyrene nanofiber nonwoven fabric includes the following steps. (1) Dissolve polystyrene resin and PP-g-MAH in DMF to prepare a solution with a polymer concentration of 15 to 25% by weight. (2) Electrospin the solution obtained in step (1) to prepare modified polystyrene nanofiber nonwoven fabric. The electrospinning voltage is 25-35 kv, the forward speed is 4-6 μl / min, and the ambient temperature and humidity are controlled at 20-25 °C and 25-35%, respectively. (3) The modified polystyrene nanofiber nonwoven fabric obtained in (2) is pulverized to obtain small pieces of nonwoven fabric.

[0011] Preferably, in step (1), a solution having a polymer concentration of 20% by weight is prepared.

[0012] Preferably, in step (2), the electrospinning voltage is controlled at 30 kV, the advance speed is controlled at 5 μl / min, and the ambient temperature and humidity are controlled at 23° C. and 30%.

[0013] More preferably, the melt index flow rate MI (200° C.×5 kg) of the polystyrene resin is 3 to 8 g / 10 min.

[0014] The polypropylene-based resin preferably contains one or both of a copolymer polypropylene resin and a homopolymer polypropylene resin.

[0015] Preferably, the antioxidant is a mixture of one or more of 2,6-di-tert-butyl-4-methylphenol, dilauryl thiodipropionate, distearic acid thiodipropionate, tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-butyl) quaternary tetrahydrol diphosphite, pentaerythritol bisphosphite di(octadecanol) ester.

[0016] Preferably, the lubricant is one or a mixture of ethylene bisstearamide, stearates and silicone lubricants.

[0017] The method for preparing the nanocompatible polypropylene-polystyrene composition described above includes the steps of: adding polypropylene resin, antioxidant and lubricant into a high-speed mixer, mixing thoroughly, and then feeding it into the main feed of a screw machine; after a certain time, adding modified polystyrene nanofiber nonwoven fabric into the side feed port of the 8th zone under weight loss control, and melt extruding at an extrusion temperature of 180-210°C and a screw speed of 200-500 rpm; and then cooling to obtain a nanocompatible polypropylene-polystyrene composition. Preferably, the temperature of the seventh zone is set at 100° C. during the preparation process. Effect of the Invention

[0018] Compared with the prior art, the present invention has the following advantages: 1. The present invention can effectively improve the compatibility of polystyrene and polypropylene, and improve the comprehensive mechanical properties of polystyrene / polypropylene alloy.

[0019] 2. In the present invention, polystyrene and PP-g-MAH are mixed and electrospun to form nanofibers, which are then added to the polypropylene melt by side feeding, allowing polystyrene to be directly integrated into polypropylene in the form of a nanophase, thereby reducing the phase state of polystyrene and greatly improving the compatibility of the two.

[0020] 3. In the present invention, the PP-g-MAH compatibilizer is first mixed into polystyrene, and then melt-mixed with polypropylene. When polystyrene nanofibers are blended with polypropylene in this way, PP-g-MAH, which has better compatibility with polypropylene, can easily come out of the polystyrene phase and enter between them, improving the efficiency of the compatibilizer and enhancing the compatibility of the two.

[0021] 4. The present invention cools the polypropylene melt before adding polystyrene nanofiber, and reduces the temperature to 100°C before side feeding to prevent premature melting of polystyrene nanofiber and ensure the blending effect.

[0022] 5. The polystyrene / polypropylene resin composition obtained by the present invention has excellent toughness, chemical resistance, and high strength, is easy to produce, has low material costs, and has high production efficiency, and can compensate for the performance deficiencies of polystyrene and polypropylene. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The following describes the embodiments of the present invention in detail. The following examples are implemented on the basis of the technical solutions of the present invention, and provide detailed embodiments and specific operation processes, but do not limit the protection scope of the present invention.

[0024] (Implementation example) A method for preparing a nanocompatible polypropylene and polystyrene composition, the method comprising the steps of: (1) According to the weight percentages of the ingredients in Table 1, dissolve them in DMF to prepare a solution with a polymer concentration of 20 wt %.

[0025] [Table 1] The materials in Table 1 are as follows: Polystyrene: GPPS123P, Secco; PP-g-MAH: CMG-5001-L, Hinodesha.

[0026] (2) The solution obtained in step (1) is electrospun to prepare a modified polystyrene nanofiber nonwoven fabric. The electrospinning voltage is controlled at 30 kV, the forward speed is controlled at 5 μl / min, and the ambient temperature and humidity are controlled at 23 °C and 30%, respectively.

[0027] (3) The modified polystyrene nanofiber nonwoven fabric obtained in (2) is pulverized to obtain small pieces of nonwoven fabric.

[0028] (4) The components in Table 2 are added to a high-speed mixer in parts by weight, mixed thoroughly, and then fed into the main feed of the screw machine. At the same time, the modified polystyrene nanofiber nonwoven fabric in the parts by weight shown in Table 2 is added to the side feed port of the 8th zone by weight loss control. The melt extrusion is carried out at an extrusion temperature of 180-210°C (the 7th zone temperature is set to 100°C) and a screw rotation speed of 400 rpm, and the product is obtained by cooling and granulation.

[0029] [Table 2]

[0030] Of these, the materials in Table 2 are as follows: Polypropylene 1: PP1120, homopolymer PP, Formosa Plastics. Polypropylene 2: PP4204, impact resistant copolymer PP, Formosa Plastics. Antioxidant: 1:1 mixture of IG-1076 and IG-168, BASF. Lubricant: EBS, Sunkoo.

[0031] (Performance evaluation methods and implementation standards) Charpy notch impact strength: Measured according to ISO179-1:2010(E) standard with impact energy of 4J at 23°C. Tensile strength: Measured according to ISO527:2010(E) standard under the following conditions: 5kg, 50℃ / h. Shrinkage: measured according to GB / T 15585 standard. Compatibility: Observe the peeling condition at the gate after injection molding the sample.

[0032] (Comparative Examples 1 to 4) In Comparative Examples 3 and 4, the raw materials were added to a high-speed mixer according to the weight parts of the blended components in Table 3, mixed thoroughly, and then placed in a screw machine and melt-extruded at an extrusion temperature of 180 to 210°C and a screw rotation speed of 400 rpm. The mixture was then cooled and granulated to obtain a product.

[0033] The manufacturing method of Comparative Example 1 was the same as that of Example 1, except that the temperature of the seventh zone was set to 210°C.

[0034] The manufacturing method of Comparative Example 2 was the same as that of Example 1, except that PP-g-MAH was not added to the polystyrene nanofiber nonwoven fabric 3 in the manufacturing process.

[0035] [Table 3]

[0036] In Comparative Example 3, compared with Example 1, the compatibility of polypropylene and polystyrene is poor because the nanofiber compatibilization method is not used, the physical properties are not improved, and the performance is even worse than that of the original polypropylene 1.

[0037] In Comparative Example 1, the temperature of the seventh zone did not decrease, and the physical properties of the composition were slightly decreased, compared with Example 1.

[0038] In Comparative Example 2, the compatibility between polypropylene and polystyrene is slightly poorer than in Example 1 because the compatibilizer PP-g-MAH is not added, and the physical properties of the composition are deteriorated.

[0039] In Example 1, compared with Comparative Example 4, the compatibility of polystyrene and polypropylene was improved by nano-compatibilization, the shrinkage rate of polypropylene added with polystyrene was reduced, and the impact properties and strength were increased, resulting in optimized and improved performance.

[0040] The above description of the embodiments is intended to enable a person having ordinary skill in the art to understand and use the present invention. It is obvious that a person skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without inventive ideas. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by a person skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention shall be within the protection scope of the present invention.

Claims

1. A nanocompatible polypropylene-polystyrene composition comprising, by weight ratio, 60 to 80 parts of polypropylene resin, 20 to 40 parts of modified polystyrene nanofiber nonwoven fabric, 0.1 to 1 part of antioxidant, and 0.1 to 1 part of lubricant.

2. The modified polystyrene nanofiber nonwoven fabric is a nanofiber nonwoven fabric having a fiber diameter of 100 to 600 nm obtained by electrospinning a polystyrene resin and a PP-g-MAH composition.

3. The nanocompatible polypropylene-polystyrene composition according to claim 2, wherein the polystyrene resin and PP-g-MAH composition comprises, by weight, 98-99 parts polystyrene resin and 1-2 parts PP-g-MAH.

4. A method for producing the modified polystyrene nanofiber nonwoven fabric according to claim 2, comprising the steps of: (1) dissolving polystyrene resin and PP-g-MAH in DMF to prepare a solution having a polymer concentration of 15 to 25% by weight; (2) Electrospinning the solution obtained in step (1), controlling the electrospinning voltage at 25-35 kV and the advance speed at 4-6 μl / min at ambient temperature, with humidity controlled at 20-25° C. and 25-35%; (3) A method for producing a modified polystyrene nanofiber nonwoven fabric, comprising the step of pulverizing the modified polystyrene nanofiber nonwoven fabric obtained in the step (2) to obtain small pieces of the nonwoven fabric.

5. The nanocompatible polypropylene-polystyrene composition according to claim 2, characterized in that the polystyrene resin has a melt index flow rate MI (200°C x 5 kg) of 3 to 8 g / 10 min.

6. 2. The nanocompatible polypropylene-polystyrene composition of claim 1, wherein the polypropylene resin comprises one or both of a copolymer polypropylene resin and a homopolymer polypropylene resin.

7. 2. The nanocompatible polypropylene-polystyrene composition according to claim 1, characterized in that the antioxidant is one or several mixtures of 2,6-di-tert-butyl-4-methylphenol, dilauryl thiodipropionate, distearic acid thiodipropionate, tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-butyl) quaternary tetrahydrol diphosphite, pentaerythritol bisphosphite di(octadecanol) ester.

8. 2. The nanocompatible polypropylene-polystyrene composition of claim 1, characterized in that the lubricant is one or a mixture of several of ethylene bisstearamide, stearates and silicone lubricants.

9. A method for producing the nanocompatible polypropylene-polystyrene composition according to claim 1, comprising adding polypropylene resin, an antioxidant and a lubricant to a mixer, mixing them thoroughly, and feeding the mixture into the main feed of a screw machine. At the same time, adding a modified polystyrene nanofiber nonwoven fabric to the side feed port of the eighth zone by weight loss control. Then, melt extrusion is performed at an extrusion temperature of 180-210°C and a screw speed of 200-500 rpm, followed by cooling and granulation.

10. 10. The method for producing a nanocompatible polypropylene-polystyrene composition according to claim 9, characterized in that the temperature of the seventh zone is set at 100°C during the production process.

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