A kind of polypropylene composite plastic and preparation method thereof

Abstract

The invention belongs to the field of novel polypropylene composite materials, and specifically discloses a polypropylene composite plastic and a preparation method thereof, a polypropylene composite plastic, made of the following raw materials in parts by weight: 100 parts of polypropylene, 15-25 parts of ethylene-vinyl acetate copolymer, 6-12 parts of inorganic fibers, 3-10 parts of silane coupling agents, 2-6 parts of calcium sulfate whiskers, 1-2 parts of stabilizers, 1-2 parts of antioxidants, and 1-2 parts of toners. The polypropylene composite plastic prepared by the present invention has good low-temperature impact strength, and avoids using harmful raw materials such as talcum powder, the preparation method is simple, homopolymerized polypropylene can be used as the main raw material, and the raw material cost is low.

Description

Technical Field

[0001] The invention belongs to the field of novel polypropylene composite materials, and specifically discloses a polypropylene composite plastic and a preparation method thereof. Background Art

[0002] Polypropylene, abbreviated as PP, is a polymer formed by the addition polymerization of propylene. It is a white waxy material with a transparent and light appearance. The chemical formula is (C3H6) n , density is 0.89~0.91g / cm 3 , flammable, melting point 189°C, softens at around 155°C, and has an operating temperature range of -30 to 140°C. It is resistant to corrosion by acids, alkalis, salt solutions and a variety of organic solvents below 80°C, and can decompose under high temperature and oxidation. Polypropylene is a thermoplastic synthetic resin with excellent performance. It is a colorless, translucent, thermoplastic, lightweight general-purpose plastic with chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties and good high-wear processing properties. It is widely used in the production of fiber products such as clothing and blankets, medical equipment, automobiles, bicycles, parts, pipelines, chemical containers, etc., and is also used for food and drug packaging. However, polypropylene has poor impact strength at low temperatures. The existing technology center also has a variety of methods to modify polypropylene to enhance its impact strength at low temperatures, such as a high yield strain low-temperature impact-resistant talc-filled polypropylene material and its preparation method, which discloses the following method:

[0003] By adding polyolefin elastomer (POE), high-density polyethylene and composite nucleation masterbatch to the talc-filled copolymer polypropylene system, it not only plays a toughening role, but also improves the crystal morphology and crystallinity of PP, so that the material has good yield resistance and high low-temperature impact resistance. However, talc may irritate the eyes, nose and throat mucosa during production and use. After talc enters the human body through respiration, it can cause pulmonary talc deposition and pulmonary silicate deposition. Therefore, from the perspective of health and environmental protection, the use of talc in polypropylene composite materials should be minimized. At the same time, the above invention needs to use a mixture of two ethylene block copolymer polypropylenes and a polyolefin elastomer, which has high raw material costs and a complicated preparation process. Summary of the invention

[0004] In order to solve the above problems, the present invention discloses a polypropylene composite plastic and a preparation method thereof.

[0005] A polypropylene composite plastic is made from the following raw materials in parts by weight:

[0006]

[0007]

[0008] Furthermore, in the above-mentioned polypropylene composite plastic, the polypropylene is homopolymer polypropylene. Homopolymer polypropylene is used because the raw material is easily available and the cost is low.

[0009] Furthermore, the molecular weight of the polypropylene composite plastic is 1500-3000. In some embodiments, the composite plastic prepared by using the polypropylene raw material with the above molecular weight has strong resistance to low-temperature impact.

[0010] Furthermore, in the above-mentioned polypropylene composite plastic, the vinyl acetate content in the ethylene-vinyl acetate copolymer is 10-15%. In some embodiments, the composite plastic prepared using the ethylene-vinyl acetate copolymer raw material with the above-mentioned vinyl acetate content has strong low-temperature impact resistance.

[0011] Furthermore, in the above-mentioned polypropylene composite plastic, the inorganic fiber is selected from one of glass fiber, oyster-based fiber or carbon fiber; preferably, the use of oyster-based fiber can show more excellent performance in some embodiments, and the prepared composite plastic has strong resistance to low-temperature impact.

[0012] Furthermore, in the above-mentioned polypropylene composite plastic, the silane coupling agent is selected from isobutyltriethoxysilane. The small molecular structure of the coupling agent can penetrate the cementitious surface, penetrate deeply, inhibit water absorption, produce waterproof, Cl-proof, anti-ultraviolet properties and have air permeability.

[0013] Furthermore, in the above-mentioned polypropylene composite plastic, the average diameter of the calcium sulfate whiskers is 1.5-3 μm, and the average length is 4-10 μm. In some embodiments, the composite plastic prepared by using the above-mentioned whisker raw material has strong low-temperature impact resistance.

[0014] Furthermore, in the above-mentioned polypropylene composite plastic, the stabilizer is a PVC stabilizer. The PVC stabilizer is used because the raw materials are easily available.

[0015] Furthermore, the preparation method of the above-mentioned polypropylene composite plastic comprises the following steps:

[0016] 1) Mixing: Weigh the corresponding amount of each component, add it into an internal mixer, and mix it at 150-180°C for 15-25 minutes to obtain a mixed rubber;

[0017] 2) Open milling: the rubber mix is ​​added into an open mill, and is opened and milled at 160-200° C. for 5-15 min, and thinned 2-4 times to obtain a sheet, which is then crushed to a diameter of less than 1 cm to obtain an extrusion raw material;

[0018] 3) Extrusion: the extrusion raw material is put into an extruder and extruded to obtain the polypropylene composite plastic.

[0019] The preparation method is simple and easy to implement, can use existing equipment, and has low cost.

[0020] Furthermore, in the above-mentioned method for preparing a polypropylene composite plastic, the step 3) extrusion specifically comprises the following steps:

[0021] Extrusion in a twin-screw extruder, which has six heating zones and a die zone,

[0022] The extrusion process temperature of each zone is as follows:

[0023]

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

[0025] The invention discloses a polypropylene composite plastic. The raw material combination of polypropylene, ethylene-vinyl acetate copolymer and inorganic fiber has good low temperature resistance and low temperature impact resistance. The preparation method is simple and easy to implement, and can be produced using existing equipment with low cost. It does not need to use raw materials such as talcum powder that are harmful to health or damage the environment, and meets the requirements of green environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a comparative schematic diagram of yield strength and yield elongation of various embodiments;

[0027] Figure 2 A schematic diagram showing the comparison of the bending strength of various embodiments;

[0028] Figure 3 A schematic diagram comparing the impact strength of various embodiments. DETAILED DESCRIPTION

[0029] A polypropylene composite plastic is made from the following raw materials in parts by weight:

[0030]

[0031] The polypropylene is homopolymer polypropylene;

[0032] The molecular weight of the polypropylene is 1500-3000;

[0033] The ethylene-vinyl acetate copolymer has a vinyl acetate content of 10-15%;

[0034] The inorganic fiber is selected from one of glass fiber, oyster-based fiber or carbon fiber;

[0035] The silane coupling agent is selected from isobutyltriethoxysilane;

[0036] The calcium sulfate whiskers have an average diameter of 1.5-3 μm and an average length of 4-10 μm;

[0037] The stabilizer is a PVC stabilizer;

[0038] The method for preparing the polypropylene composite plastic comprises the following steps:

[0039] 1) Mixing: Weigh the corresponding amount of each component, add it into an internal mixer, and mix it at 150-180°C for 15-25 minutes to obtain a mixed rubber;

[0040] 2) Open milling: the rubber mix is ​​added into an open mill, and is opened and milled at 160-200° C. for 5-15 min, and thinned 2-4 times to obtain a sheet, which is then crushed to a diameter of less than 1 cm to obtain an extrusion raw material;

[0041] 3) Extrusion: putting the extrusion raw material into an extruder for extrusion to obtain the polypropylene composite plastic;

[0042] The step 3) extrusion specifically comprises the following steps:

[0043] Extrusion in a twin-screw extruder, which has six heating zones and a die zone,

[0044] The extrusion process temperature of each zone is as follows:

[0045]

[0046] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] The reagents or instruments used in the examples of the present invention without indicating the manufacturer are all conventional reagent products that can be obtained through commercial purchase.

[0048] The oyster-based fiber is prepared using the following process, including the following steps:

[0049] S1 Oyster shell pretreatment: first take the oyster shell, wash the surface with water, place it in a solution containing an oxidant for disinfection, and then oscillate it with ultrasound for 10-20 minutes with an ultrasonic power of 400-1000W. Then immerse the oyster shell in an acidic solution and heat it to 60-90℃ for 1-2 hours, pick it up, wash it, and dry it;

[0050] The oxidant is selected from one of potassium dichromate, sodium hypochlorite or hydrogen peroxide; the acidic solution is one of dilute hydrochloric acid, dilute sulfuric acid and dilute nitric acid;

[0051] S2 Calcination: The pretreated oyster shells are placed in a rotary kiln and heated to 180-220°C for calcination for 4-8 hours, and then cooled to room temperature;

[0052] S3 crushing: the calcined oyster shells are transferred to a crusher for primary crushing, and the oyster shells are sieved through a 300-mesh to 500-mesh sieve to obtain coarse oyster shell powder;

[0053] S4 grinding: transferring the crushed oyster shell coarse powder to a powerful bead mill, adding an organic oligomer dispersant and a powder surface modifier, and grinding to ultrafine oyster shell powder with a particle size of 100-800 nm;

[0054] The organic oligomer dispersant is selected from one of vinyl bisstearamide, ethylene-vinyl acetate, and oxidized polyethylene wax, and the amount of the organic oligomer dispersant added is 0.5-1% of the mass of the oyster shell coarse powder;

[0055] The powder surface modifier is composed of the following raw materials in parts by mass: 100 parts of ethylene-vinyl acetate copolymer, 15-25 parts of magnesia, and 10-20 parts of dioctyl phthalate; the amount of the powder surface modifier added is 1% of the mass of the oyster shell coarse powder;

[0056] S5 aggregation:

[0057] 1) dissolving ultrafine oyster shell powder, chitosan and polyethylene terephthalate in a mass ratio of 1:2:3 in a 20% acetic acid solution having the same weight as the above raw materials, stirring at room temperature for 10-20 minutes to obtain a reaction solution;

[0058] 2) adding polyvinyl alcohol resin to the reaction solution, wherein the mass ratio of the polyvinyl alcohol resin to the reaction solution is 2:1-4:1; heating to 95-105° C., stirring for reaction for 30-60 min, cooling to room temperature for solidification, and obtaining a masterbatch;

[0059] S6 granulation: the masterbatch is put into a twin-screw extruder for extrusion granulation, wherein the screw segment temperature in the twin-screw granulator is controlled to be 240-300°C, the temperature of each segment increases successively, the pelletizing speed is 200-300r / min, and the feeding speed is 150-200r / min to obtain the masterbatch;

[0060] S7 liquid preparation: subjecting the masterbatch obtained in step 6 above to high temperature treatment, heating it to 150-200°C in a stirred reactor, controlling the pressure to 0.25-0.4Mpa, stirring and reacting for 40-70 minutes, and obtaining a fiber liquid;

[0061] S8 filamentation: add the above fiber liquid into a spinning machine for dry spinning; during extrusion, the spinning fiber liquid temperature is 90-105°C, the spinneret aperture is 0.005-0.01mm, nitrogen hot air protection is used near the spinneret aperture, the hot air temperature is 110-130°C, the hot air temperature at the bottom of the tunnel is 200-260°C, the tunnel height is 0.4-0.8cm, and the tunnel diameter is 0.2-0.5cm; the spinning speed is 15-25m / min; a mechanical stretching system is used for stretching, and the stretching temperature is 170-200°C.

[0062] Example 1

[0063] A polypropylene composite plastic is made from the following raw materials in parts by weight:

[0064]

[0065] The polypropylene is homopolymer polypropylene;

[0066] The molecular weight of the polypropylene is 1500;

[0067] The ethylene-vinyl acetate copolymer has a vinyl acetate content of 10%;

[0068] The inorganic fibers are selected from glass fibers;

[0069] The silane coupling agent is selected from isobutyltriethoxysilane;

[0070] The calcium sulfate whiskers have an average diameter of 1.5 μm and an average length of 4 μm;

[0071] The stabilizer is a PVC stabilizer;

[0072] The method for preparing the polypropylene composite plastic comprises the following steps:

[0073] 1) Mixing: Weigh the corresponding amount of each component, add it into an internal mixer, and mix it at 150-180°C for 15-25 minutes to obtain a mixed rubber;

[0074] 2) Open milling: the rubber mix is ​​added into an open mill, and is opened and milled at 160-200° C. for 5-15 min, and thinned 2-4 times to obtain a sheet, which is then crushed to a diameter of less than 1 cm to obtain an extrusion raw material;

[0075] 3) Extrusion: putting the extrusion raw material into an extruder for extrusion to obtain the polypropylene composite plastic;

[0076] The step 3) extrusion specifically comprises the following steps:

[0077] Extrusion in a twin-screw extruder, which has six heating zones and a die zone,

[0078] The extrusion process temperature of each zone is as follows:

[0079]

[0080] Example 2

[0081] A polypropylene composite plastic is made from the following raw materials in parts by weight:

[0082]

[0083] The polypropylene is homopolymer polypropylene;

[0084] The molecular weight of the polypropylene is 2500;

[0085] The ethylene-vinyl acetate copolymer has a vinyl acetate content of 12%;

[0086] The inorganic fiber is selected from oyster-based fibers;

[0087] The silane coupling agent is selected from isobutyltriethoxysilane;

[0088] The calcium sulfate whiskers have an average diameter of 2 μm and an average length of 5 μm;

[0089] The stabilizer is a PVC stabilizer;

[0090] The method for preparing the polypropylene composite plastic comprises the following steps:

[0091] 1) Mixing: Weigh the corresponding amount of each component, add it into an internal mixer, and mix it at 150-180°C for 15-25 minutes to obtain a mixed rubber;

[0092] 2) Open milling: the rubber mix is ​​added into an open mill, and is opened and milled at 160-200° C. for 5-15 min, and thinned 2-4 times to obtain a sheet, which is then crushed to a diameter of less than 1 cm to obtain an extrusion raw material;

[0093] 3) Extrusion: putting the extrusion raw material into an extruder for extrusion to obtain the polypropylene composite plastic;

[0094] The step 3) extrusion specifically comprises the following steps:

[0095] Extrusion in a twin-screw extruder, which has six heating zones and a die zone,

[0096] The extrusion process temperature of each zone is as follows:

[0097]

[0098] Example 3

[0099] A polypropylene composite plastic is made from the following raw materials in parts by weight:

[0100]

[0101] The polypropylene is homopolymer polypropylene;

[0102] The molecular weight of the polypropylene is 3000;

[0103] The ethylene-vinyl acetate copolymer has a vinyl acetate content of 15%;

[0104] The inorganic fiber is selected from carbon fiber;

[0105] The silane coupling agent is selected from isobutyltriethoxysilane;

[0106] The average diameter of the calcium sulfate whiskers is 3 μm and the average length is 10 μm;

[0107] The stabilizer is a PVC stabilizer;

[0108] The method for preparing the polypropylene composite plastic comprises the following steps:

[0109] 1) Mixing: Weigh the corresponding amount of each component, add it into an internal mixer, and mix it at 150-180°C for 15-25 minutes to obtain a mixed rubber;

[0110] 2) Open milling: the rubber mix is ​​added into an open mill, and is opened and milled at 160-200° C. for 5-15 min, and thinned 2-4 times to obtain a sheet, which is then crushed to a diameter of less than 1 cm to obtain an extrusion raw material;

[0111] 3) Extrusion: putting the extrusion raw material into an extruder for extrusion to obtain the polypropylene composite plastic;

[0112] The step 3) extrusion specifically comprises the following steps:

[0113] Extrusion in a twin-screw extruder, which has six heating zones and a die zone,

[0114] The extrusion process temperature of each zone is as follows:

[0115]

[0116] Comparative Example 1

[0117] A polypropylene composite plastic is made from the following raw materials in parts by weight:

[0118]

[0119] The polypropylene is homopolymer polypropylene;

[0120] The molecular weight of the polypropylene is 2500;

[0121] The inorganic fiber is selected from oyster-based fibers;

[0122] The silane coupling agent is selected from isobutyltriethoxysilane;

[0123] The calcium sulfate whiskers have an average diameter of 2 μm and an average length of 5 μm;

[0124] The stabilizer is a PVC stabilizer;

[0125] The method for preparing the polypropylene composite plastic comprises the following steps:

[0126] 1) Mixing: Weigh the corresponding amount of each component, add it into an internal mixer, and mix it at 150-180°C for 15-25 minutes to obtain a mixed rubber;

[0127] 2) Open milling: the rubber mix is ​​added into an open mill, and is opened and milled at 160-200° C. for 5-15 min, and thinned 2-4 times to obtain a sheet, which is then crushed to a diameter of less than 1 cm to obtain an extrusion raw material;

[0128] 3) Extrusion: putting the extrusion raw material into an extruder for extrusion to obtain the polypropylene composite plastic;

[0129] The step 3) extrusion specifically comprises the following steps:

[0130] Extrusion in a twin-screw extruder, which has six heating zones and a die zone,

[0131] The extrusion process temperature of each zone is as follows:

[0132]

[0133] Compared with Example 2, no ethylene-vinyl acetate copolymer is contained.

[0134] Comparative Example 2

[0135] A polypropylene composite plastic is made from the following raw materials in parts by weight:

[0136]

[0137] The polypropylene is homopolymer polypropylene;

[0138] The molecular weight of the polypropylene is 2500;

[0139] The ethylene-vinyl acetate copolymer has a vinyl acetate content of 12%;

[0140] The silane coupling agent is selected from isobutyltriethoxysilane;

[0141] The calcium sulfate whiskers have an average diameter of 2 μm and an average length of 5 μm;

[0142] The stabilizer is a PVC stabilizer;

[0143] The method for preparing the polypropylene composite plastic comprises the following steps:

[0144] 1) Mixing: Weigh the corresponding amount of each component, add it into an internal mixer, and mix it at 150-180°C for 15-25 minutes to obtain a mixed rubber;

[0145] 2) Open milling: the rubber mix is ​​added into an open mill, and is opened and milled at 160-200° C. for 5-15 min, and thinned 2-4 times to obtain a sheet, which is then crushed to a diameter of less than 1 cm to obtain an extrusion raw material;

[0146] 3) Extrusion: putting the extrusion raw material into an extruder for extrusion to obtain the polypropylene composite plastic;

[0147] The step 3) extrusion specifically comprises the following steps:

[0148] Extrusion in a twin-screw extruder, which has six heating zones and a die zone,

[0149] The extrusion process temperature of each zone is as follows:

[0150]

[0151] Compared to Example 2, the inorganic fibers are absent.

[0152] Comparative Example 3

[0153] A polypropylene composite plastic is made from the following raw materials in parts by weight:

[0154]

[0155] The polypropylene is homopolymer polypropylene;

[0156] The molecular weight of the polypropylene is 2500;

[0157] The silane coupling agent is selected from isobutyltriethoxysilane;

[0158] The calcium sulfate whiskers have an average diameter of 2 μm and an average length of 5 μm;

[0159] The stabilizer is a PVC stabilizer;

[0160] The method for preparing the polypropylene composite plastic comprises the following steps:

[0161] 1) Mixing: Weigh the corresponding amount of each component, add it into an internal mixer, and mix it at 150-180°C for 15-25 minutes to obtain a mixed rubber;

[0162] 2) Open milling: the rubber mix is ​​added into an open mill, and is opened and milled at 160-200° C. for 5-15 min, and thinned 2-4 times to obtain a sheet, which is then crushed to a diameter of less than 1 cm to obtain an extrusion raw material;

[0163] 3) Extrusion: putting the extrusion raw material into an extruder for extrusion to obtain the polypropylene composite plastic;

[0164] The step 3) extrusion specifically comprises the following steps:

[0165] Extrusion in a twin-screw extruder, which has six heating zones and a die zone,

[0166] The extrusion process temperature of each zone is as follows:

[0167]

[0168]

[0169] Compared with Example 2, ethylene-vinyl acetate copolymer and inorganic fibers are absent.

[0170] Comparative Example 4

[0171] CN202011567382.8 Example 3 of a high yield strain, low temperature impact resistant talc powder filled polypropylene material and its preparation method.

[0172] Test Case

[0173] The composite plastics of Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests according to the following methods.

[0174] Test Method

[0175] (1) Yield performance shall be in accordance with DIN EN ISO527;

[0176] (2) Bending properties shall be in accordance with DIN EN ISO178;

[0177] (3) Impact performance is in accordance with DIN EN ISO179.

[0178] The results are shown in Table 1 and Attachment Figure 1-3 Shown

[0179] Table 1 Performance test

[0180]

[0181] It can be seen from the data in the above table that Examples 1-3 use a raw material combination of polypropylene, ethylene-vinyl acetate copolymer and inorganic fiber, which has good mechanical strength, low temperature resistance, and low temperature impact resistance. And, it can be seen that the effect of using carbon fiber is better than oyster-based fiber and better than glass fiber. However, from a cost perspective, a new type of oyster-based fiber can be used. In comparison, the mechanical strength and low temperature impact resistance of Comparative Examples 1-3, which lack ethylene-vinyl acetate copolymer or inorganic fiber, are greatly reduced. From Comparative Example 4, the present invention uses a technical solution that does not contain talcum powder, and compared with the prior art Comparative Example 4, only homopolymer polypropylene with cost disclosure is needed, which is more environmentally friendly and reduces costs.

[0182] The above are only a few preferred embodiments of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A polypropylene composite plastic, characterized in that: Made from the following raw materials in parts by weight: Polypropylene 100 parts, Ethylene-vinyl acetate copolymer 15-25 parts 6-12 parts of inorganic fiber Silane coupling agent 3-10 parts Calcium sulfate whiskers 2-6 parts 1-2 parts of stabilizer 1-2 parts antioxidant 1-2 parts of color powder; The polypropylene is homopolymer polypropylene; The molecular weight of the polypropylene is 1500-3000; The ethylene-vinyl acetate copolymer has a vinyl acetate content of 10-15%; The inorganic fiber is selected from oyster-based fibers; The silane coupling agent is selected from isobutyltriethoxysilane; The calcium sulfate whiskers have an average diameter of 1.5-3 μm and an average length of 4-10 μm; The stabilizer is a PVC stabilizer; The preparation method of the polypropylene composite plastic comprises the following steps: 1) Mixing: Weigh the corresponding amount of each component, add it into an internal mixer, and mix it at 150-180℃ for 15-25min to obtain a mixed rubber; 2) Open milling: the rubber mix is ​​added into an open mill, and is opened and milled at 160-200° C. for 5-15 min, and thinned 2-4 times to obtain a sheet, which is then crushed to a diameter of less than 1 cm to obtain an extrusion raw material; 3) Extrusion: feeding the extrusion raw material into an extruder for extrusion to obtain the polypropylene composite plastic; The step 3) extrusion specifically comprises the following steps: Extrusion in a twin-screw extruder, which has six heating zones and a die zone, The extrusion process temperature of each zone is as follows: The first zone is 135℃, the second zone is 145℃, The third zone is 155℃, the fourth zone is 165℃, The fifth zone is 175°C, the sixth zone is 165°C, Die zone 155℃; Discharge temperature: 155℃.

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