CN102002187A - Method for filling and modifying polypropylene by egg shell powder - Google Patents

Abstract

The invention relates to a method for filling modified polypropylene (PP) materials with egg shell powder. The specific steps of the method are as follows: soak the egg shells, wash and dry them, and roughly crush them to collect 1-30 μm egg shell powder; then press the mass ratio of egg shell powder: Φ6 agate balls = 1:4-5, Dry ball milling for 4 to 8 hours; add the egg shell powder obtained in step a or the modified egg shell powder obtained in step a to polypropylene, and the mass ratio is egg shell powder:polypropylene:toughener:compatibilizer Agent = 10～25: 65～85: 5: 0～5, with liquid paraffin as auxiliary mixing, extruded and pelletized by twin-screw extruder, processing temperature range is 180-215°C, twin-screw speed is 150-180 rpm /min to obtain modified polypropylene filled with egg shell powder. Compared with the unmodified nano-calcium carbonate-filled PP, the surface-unmodified egg shell powder-filled PP of the present invention has higher Young's modulus, better impact resistance and similar bending performance. The surface-modified egg shell powder filled PP has slightly lower tensile and bending properties, and better impact resistance.

Description

Method for filling modified polypropylene with egg shell powder

technical field

The invention relates to a modification method of polypropylene (PP) material. It particularly relates to a method for filling modified polypropylene (PP) materials with egg shell powder.

Background technique

my country is a large egg-producing country, and its output ranks first in the world year after year. In 2007, China produced 25.29 million tons of eggs in 2007 and 27.022 million tons in 2008. During the processing of eggs, a large number of eggshells were produced, which were basically thrown away as waste, which not only polluted the environment, but also wasted resources. The egg shell is mainly composed of inorganic substances, 93% of which is calcium carbonate. There is a shell membrane between the eggshell and the egg white. When the egg shell is formed, the carbonate ion reacts with the calcium ion in the hen's uterus through the shell membrane. , the generated calcium carbonate is deposited on the surface of the shell membrane. During the reaction, the shell membrane provides a nucleation site and controls the crystal structure of the eggshell.

Calcium carbonate is widely used in rubber, plastics, fibers, non-woven fabrics, films, coatings and other fields. There have been a large number of literature discussions on the use of plastic fillers. There are precedents for using calcium carbonate made from biological materials as a filler. Chinese patent CN 1475520A describes in detail the method for making shell powder (with natural shells through crushing, alkali treatment, decolorization and oxidation) and the surface modification of shell powder, and the modified shell powder is used in plastics, coatings, paints, in latex. The processing steps of this method are complicated, involving various chemical reagents, and after multi-step chemical processing, the natural calcium carbonate crystal form may not be maintained. It does not reflect the advantages of natural inorganic powders, which are green, environmentally friendly and low-carbon.

The Chinese patent CN 101230207A uses crushing, roasting, and air oxidation methods to prepare natural calcium carbonate powder (<5 μm), and uses it as a filler to improve the mechanical and thermal properties of polymer materials. This method cannot guarantee the uniformity of particle size and crystal structure after calcination.

In foreign literature, Patricio Toro et al. stated in the article Eggshell, a new bio-filler for polypropylene composites, materials letter.61 (2007) 4347: Compared with talc (Talc) and calcium carbonate (CaCO ₃ ) mineral powder, egg powder has The lower the density, the egg shell powder can better induce the crystallization of PP. Even though the size of egg shell powder is larger than that of talc (Talc) and calcium carbonate (CaCO ₃ ) mineral powder, egg shell powder modified PP has higher Young's modulus. In the article Mechanical and Morphological Studies of Poly (propylene)-Filled Eggshell Composites, Macromolecular materials and engineering. 292 (2007) 1027, Patricio Toro et al. further compared egg powder, Talc and CaCO ₃ with 0-60% filling ratio. Tensile and impact resistance properties of permanent PP. It is concluded that PP modified by Talc has comprehensive and excellent comprehensive mechanical properties, and PP modified by 400 mesh egg shell powder has the best tensile properties. Different ratios of eggshell powder/Talc mixed modified PP and Talc filled modified PP have similar properties.

U.S. Patent No. 7,459,492B2 by Patricio Toro et al. describes the modification of egg shell powder, which is based on the results of the research in the above two articles. It is obtained that 30% 400 mesh egg shell powder and 10% talc jointly modify PP. The best result. This patent elaborates on the preparation and application of egg shell powder: hand-grind the egg shell powder to 100 mesh with a porcelain mortar, then dry it in an oven at 100-110°C for 8-9 hours, and use mechanical grinding and pass through after drying. Sieve to obtain 400 mesh egg powder. Mix egg powder or mineral powder with PP in a mixer, knead at 190~195°C at 70~75rpm for 10~15min under inert gas protection, and mix at 30~40°C and 40~50bar Tablet forming. There is no shell membrane separation step in the preparation process of the eggshell powder of this patent. Since there is only 8% calcium carbonate in the eggshell membrane, there are bound to be more impurities in the prepared eggshell powder, which will affect the performance of the final modified product. ; The particle size of the added egg shell powder is relatively large, 400 mesh, and the particle size test is X ₁₀ =1.7, X ₅₀ =8.4, X ₉₀ =27.5, which does not reach the submicron structure mentioned in the article, and the overall particle size is relatively large or The agglomeration is very serious; when evaluating the results, only the Young's modulus is regarded as the most important evaluation, and it is inevitable that there will be bias.

Contents of the invention

The purpose of the present invention is to provide a method for filling modified polypropylene with egg shell powder, so that discarded egg shells can be fully and effectively utilized, and a practical modified polypropylene PP with balanced mechanical properties can be prepared.

For achieving above object, the technical scheme that the present invention adopts is as follows:

A method for filling modified polypropylene with egg shell powder, characterized in that the specific steps of the method are:

a. Soak the egg shell, wash and dry it, then roughly crush it to collect 1-30μm egg shell powder; then press the egg shell powder: Φ6 agate ball = 1:4-5 mass ratio, dry ball mill 4-5 8 hours;

b. Add the egg shell powder obtained in step a or the modified egg shell powder obtained in step a to polypropylene, and the mass ratio is: egg shell powder: polypropylene: toughening agent = 10-25: 70-85 : 5, with liquid paraffin as auxiliary mixing, twin-screw extruder to extrude and pelletize, the processing temperature range is 180-215 ° C, and the twin-screw speed is 150-180 rpm to obtain modified polypropylene filled with egg shell powder.

The specific method of modifying the above-mentioned egg shell powder is as follows: mix the egg shell powder obtained in step a according to the mass ratio of egg shell powder:solvent=1:1~2, and add 100% of the mass of egg shell powder under the condition of 70°C 1-2% coupling agent, then add 3-5% stearic acid, polybutyl acrylate or polyethyl acrylate based on the mass of egg shell powder, stir and heat to reflux for 1-2 hours, and then filter and dry; A modified egg shell powder is obtained.

The egg shell powder obtained in the above step a has a flake structure, the particle diameter is in the range of nanoscale, and the specific surface area is 10.0 m ² /g.

The above-mentioned solvent is absolute ethanol or isopropanol.

The above-mentioned coupling agent is γ-aminopropyltriethoxysilane (KH-550).

The above toughening agent is polyethylene octene co-elastomer or polyethylene butene co-elastomer or maleic anhydride grafted polyethylene octene elastomer.

Compared with the unmodified nano-calcium carbonate-filled PP, the surface-unmodified egg shell powder-filled PP of the present invention has higher Young's modulus, better impact resistance and similar bending performance. The surface-modified egg shell powder filled PP has slightly lower tensile and bending properties, and better impact resistance.

Description of drawings

Fig. 1 is egg shell powder and nano-calcium carbonate XRD pattern;

Fig. 2 is the SEM picture of egg shell powder after ball milling;

Fig. 3 is nano-calcium carbonate SEM figure;

Fig. 4 is the performance test result table of polypropylene gained in each embodiment of the present invention;

Figure 5 is a list of comparison standards for each performance test.

Detailed ways

The present invention will be further described below by way of examples and comparative examples. Under the condition of not violating the purpose of the present invention, the present invention should not be limited to the specific express contents of the following experimental examples.

Embodiment 1: Soak egg shells, wash them, and initially dry them at 105° C. until the outer shells are just dry and the inner membrane is relatively moist, then separate the shell membranes and continue drying. After the dried egg shells are coarsely crushed, they are processed by jet crushing to obtain egg shell powder with a thickness of 1-30 μm. Sieve through a 500-mesh sieve, add the prepared egg shell powder to PP, the basic ratio is egg shell powder: PP: toughening agent = 15:80:5, liquid paraffin auxiliary mixing, twin-screw extruder extrusion For pelletizing, the processing temperature range is 180-215°C, and the twin-screw speed is 180 rpm. The toughening agent used is polyethylene octene co-elastomer. the

Example 2

Soak the egg shells, wash them, and initially dry them at 105°C until the shells are just dry and the inner membrane is relatively moist, then separate the shells and membranes, and continue drying. After the dried egg shells are coarsely crushed, they are processed by jet crushing to obtain egg shell powder with a thickness of 1-30 μm. The obtained egg shell powder is ball milled with a ball mill. The specific treatment process is egg shell powder: Φ6 agate ball = 1:4, dry ball milling for 4 hours. The prepared egg shell powder is added to PP, the basic ratio is egg shell powder: PP: toughening agent = 15:80:5, liquid paraffin is mixed, the twin-screw extruder is extruded and pelletized, and the processing temperature range is 180-215°C, the twin-screw speed is 180 rpm. The toughening agent used is polyethylene octene co-elastomer.

Example 3

Soak the egg shells, wash them, and initially dry them at 105°C until the shells are just dry and the inner membrane is relatively moist, then separate the shells and membranes, and continue drying. After the dried egg shells are coarsely crushed, they are processed by jet crushing to obtain egg shell powder with a thickness of 1-30 μm. The obtained egg shell powder is ball milled with a ball mill. The specific treatment process is egg shell powder: Φ6 agate ball = 1:4, dry ball milling for 4 hours. The prepared egg shell powder is added to PP, the basic ratio is egg shell powder: PP: toughening agent = 20:75:5, liquid paraffin auxiliary mixing, twin-screw extruder extrusion pelletization, the processing temperature range is 180-215°C, the twin-screw speed is 180 rpm. The toughening agent used is polyethylene octene co-elastomer.

Example 4

Soak the egg shells, wash them, and initially dry them at 105°C until the shells are just dry and the inner membrane is relatively moist, then separate the shells and membranes, and continue drying. After the dried egg shells are coarsely crushed, they are processed by jet crushing to obtain egg shell powder with a thickness of 1-30 μm. The obtained egg shell powder is ball milled with a ball mill. The specific treatment process is egg shell powder: Φ6 agate ball = 1:4, dry ball milling for 4 hours. Surface modification of egg shell powder. Egg powder: absolute ethanol = 1:2, at 70°C, first add 1.2% coupling agent of egg shell powder mass, then add 3% sodium stearate, heat and reflux under stirring for about 90 minutes. After the modification is completed, it can be dried after suction filtration. The prepared egg shell powder is added to PP, the basic ratio is egg shell powder: PP: toughening agent = 15:80:5, liquid paraffin is mixed, the twin-screw extruder is extruded and pelletized, and the processing temperature range is 180-215°C, the twin-screw speed is 180 rpm. The toughening agent used is polyethylene octene co-elastomer.

Example 5

The nano-calcium carbonate is mixed according to the ratio of nano-calcium carbonate: PP: toughener = 15:80:5, mixed with liquid paraffin, extruded and pelletized by a twin-screw extruder, and the processing temperature range is 180-215 ° C, twin-screw The rotating speed is 180 rpm. The toughening agent used is polyethylene octene co-elastomer.

Example 6

Surface modification of nano calcium carbonate. Nano-calcium carbonate: absolute ethanol = 1:2, under the condition of 70 ℃, first add 1.2% coupling agent of nano-calcium carbonate quality, then add 3% stearic acid, heat and reflux under stirring, about 90min. After the modification is completed, it can be dried after suction filtration. Add the modified nano-calcium carbonate to PP, the basic ratio is nano-calcium carbonate: PP: toughening agent = 15:80:5, liquid paraffin auxiliary mixing, twin-screw extruder extruding pelletizing, processing temperature range The temperature is 180-215°C, and the twin-screw speed is 180 rpm. The toughening agent used is polyethylene octene co-elastomer.

The XRD of the prepared egg shell micropowder and the contrasting nano-calcium carbonate in the present invention are as shown in Figure 1. The crystal forms of the two are very similar. Comparing with the relevant data of the PDF standard card (PDF No: 41-1475, 05-0586), it can be determined that the crystal form of the calcium carbonate sample is calcite. The diffraction surfaces corresponding to the diffraction peaks near the position of diffraction angle 2θ at 23.04o, 29.40o, 36.00o, 39.40o, 43.16o, 47.48o, and 48.50o are (012), (104), (110), ( 113), (202), (018) and (116). The coordinates of the characteristic diffraction peak of egg shell powder are (29.59, 371), and the characteristic diffraction diffraction coordinates of nano-calcium carbonate are (29.59, 327). It can be seen that the peak intensity of nano-calcium carbonate is lower than that of egg shell powder.

The SEM images of the egg shell powder prepared after ball milling in the present invention and the comparative nano-calcium carbonate are shown in Fig. 2 and Fig. 3 . It can be seen that egg shell powder has a lamellar structure with irregular particle sizes, mostly at the nanometer scale, and the outline is not as clear as nano-calcium carbonate, and it is easier to agglomerate.

The performance test results of the polypropylene obtained in each embodiment of the present invention are shown in Fig. 4 . Compared with nano-calcium carbonate, when the egg shell prepared in the present invention is filled with modified PP, it has higher Young's modulus, better impact resistance and heat resistance, and similar bending performance. The method is simple, feasible, green and environmentally friendly, effectively solves the environmental pollution caused by egg shells, and at the same time opens up a new way to prepare filled modified PP plastic particles with excellent performance. The performance test is carried out according to the standards in Figure 5.

Claims (6)

1. A method for filling modified polypropylene with egg shell powder, characterized in that the concrete steps of the method are: a. Soak the egg shell, wash and dry it, then roughly crush it to collect 1-30μm egg shell powder; then press the egg shell powder: Φ6 agate ball = 1:4-5 mass ratio, dry ball mill 4-5 8 hours; b. Add the egg shell powder obtained in step a or the modified egg shell powder obtained in step a to polypropylene, and the mass ratio is: egg shell powder: polypropylene: toughening agent = 10-25: 70-85 : 5, with liquid paraffin as auxiliary mixing, twin-screw extruder to extrude and pelletize, the processing temperature range is 180-215 ° C, and the twin-screw speed is 150-180 rpm to obtain modified polypropylene filled with egg shell powder. 2. The method for filling modified polypropylene with egg shell powder according to claim 1, characterized in that the modified concrete method of said egg shell powder is: the egg shell powder obtained in step a is divided into egg shell powder: solvent =1:1~2 mass ratio mixing, under the condition of 70℃, first add 1~2% coupling agent of egg shell powder mass, then add 3~5% of egg shell powder mass stearic acid, polyacrylic acid Butyl ester or polyethyl acrylate is heated to reflux under stirring for 1 to 2 hours, and after suction filtration and drying, modified egg shell powder is obtained. 3. The method for filling modified polypropylene with egg shell powder according to claim 2, characterized in that the egg shell powder prepared after ball milling has a flake structure, the particle diameter is in the nanoscale range, and the specific surface area is 10.0 m ² /g . 4. The method for filling modified polypropylene with egg shell powder according to claim 1, characterized in that the solvent is ethanol or isopropanol. 5. The method for filling modified polypropylene with egg shell powder according to claim 1, characterized in that the coupling agent is γ-aminopropyltriethoxysilane. 6. The method for filling modified polypropylene with egg shell powder according to claim 1, characterized in that the toughening agent is polyethylene octene co-elastomer, polyethylene butene co-elastomer or maleic anhydride grafted polystyrene Ethylene octene elastomer.

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