CN106243500A - The preparation method of a kind of polypropylene modification composite and product thereof - Google Patents

Abstract

The invention provides a method for preparing a composite material for polypropylene modification, comprising the following steps: adjusting wollastonite powder into a 50%-60% slurry with water, adding sodium stearate; mixing barium sulfate and titanium dioxide according to The mass ratio is (4-6): 1 and water is made into a 65-70% composite slurry, and sodium stearate and silane coupling agent are added; the prepared titanium dioxide-barium sulfate composite slurry is wet-ground to 3000 ‑4000 mesh; add the prepared wollastonite slurry into the prepared titanium dioxide‑barium sulfate composite slurry, the mass ratio of titanium dioxide‑barium sulfate to wollastonite is (10‑12):1, and then add silane The coupling agent is coated; the composite slurry is dried to obtain a composite material dry powder; the composite material dry powder is broken up and depolymerized, and then classified by a cyclone to collect a powder of 2500-3000 mesh. The invention can obtain a composite material product with high weather resistance, high gloss and high chemical stability.

Description

A kind of preparation method and product of composite material for polypropylene modification

【Technical field】

The invention relates to the field of modified fillers, in particular to a preparation method of a composite material for polypropylene modification and a product thereof.

【Background technique】

Polypropylene (PP) is one of the five general-purpose plastics, but the biggest disadvantage of polypropylene is its brittleness, low impact strength, especially poor low-temperature impact performance, low dimensional accuracy, insufficient rigidity, and poor weather resistance, which limit its application. Scope and feature development. In order to improve various properties of polypropylene, it needs to be modified. At present, the modification methods used for polypropylene are mainly chemical modification and physical modification. Chemical modification mainly changes the molecular structure of polypropylene through copolymerization, grafting, etc. to change its properties. The molecular aggregation structure of polypropylene can be changed by mixing, strengthening, filling, etc. without changing its molecular structure to achieve the purpose of improving performance. Both chemical modification and physical modification can improve the performance of polypropylene, but chemical modification is often limited by many conditions, a large number of experiments are required to achieve success, and the cost of modification is high, while physical modification has advantages compared with it. Quick results, simple test and other advantages. Among the physical modification methods, filling modification is to add inorganic or organic fillers to polypropylene to endow polypropylene molecules with the properties of fillers, so as to achieve the purpose of modification. Filling modification is one of the methods of polypropylene and even plastic modification. It is a very widely used method, which can not only improve the performance of plastics, but also reduce costs.

Inorganic materials commonly used to fill modified polypropylene include calcium carbonate, talc, silicon dioxide, barium sulfate, kaolin, mica, wollastonite, etc. In the usual inorganic modification process, one kind or several different fillers are added alone to modify polypropylene by melt blending and other processes. Adding one type of filler often does not improve the performance of polypropylene significantly or is not perfect. When different fillers are added alone, there is often no organic combination between fillers or between fillers and resins, resulting in poor polypropylene modification effect and modified polypropylene performance. The improvement is not obvious.

【Content of invention】

In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a preparation method of a composite material for polypropylene modification and its product, which can obtain a composite reinforcement material suitable for polypropylene modification.

Technical scheme of the present invention is:

A kind of preparation method of composite material for polypropylene modification, is characterized in that, comprises the following steps:

(1) 400-600 mesh wollastonite powder is adjusted into a slurry with a mass concentration of 50%-60% with water, and sodium stearate is added as a dispersant;

(2) 400-600 mesh barium sulfate and 300-400 mesh titanium dioxide are made into a composite slurry with a mass concentration of 65-70% in a mass ratio of (4-6): 1, and sodium stearate and silane are added. The joint agent is used as a dispersant and a surface modifier;

(3) Put the titanium dioxide-barium sulfate composite slurry prepared in (2) into the wet vertical grinding machine and wet grind to 3000-4000 mesh;

(4) Put the wollastonite slurry prepared in (1) into the wet vertical grinder, add the titanium dioxide-barium sulfate composite slurry prepared in (3), titanium dioxide-barium sulfate and The mass ratio of wollastonite is (10-12): 1, then add silane coupling agent for coating, and wet grinding until the average particle diameter D of _wollastonite particles is 2.0-2.5 μm;

(5) feed the composite slurry obtained in (4) into a flash dryer, and control the hot air inlet temperature at 370-390° C. to obtain a composite material dry powder;

(6) Dispersing and depolymerizing the composite material dry powder obtained in (5), and then classifying by cyclone to collect 2500-3000 mesh powder to obtain a composite material product.

The composite material organically combines wollastonite, titanium dioxide and barium sulfate through mechanochemical method, so that titanium dioxide and barium sulfate are evenly distributed on the wollastonite whiskers, and a high weather resistance, high gloss, Composite reinforcement with high chemical stability. Among composite materials, wollastonite has good fiber structure, high aspect ratio and corrosion resistance, which can improve the mechanical strength of polypropylene such as tensile and bending resistance, and titanium dioxide after surface modification can provide good heat resistance. , weather resistance and high decolorizing power, high-purity ultra-fine natural barium sulfate has a dense crystal form and excellent chemical stability, which can improve the surface gloss and processing fluidity of polypropylene.

Further, the amount of sodium stearate added in the above step (1) is 2‰-5‰ of the wollastonite powder mass, so as to improve the dispersibility and grindability of the slurry.

Further, the amount of sodium stearate added in the above step (2) is 3-5% of the sum of the mass of barium sulfate and titanium dioxide, so as to improve the dispersibility and grindability of the slurry.

Further, the silane coupling agent in the above step (2) is 2-4‰ of the sum of the mass of barium sulfate and titanium dioxide, so as to achieve organic silicon coating on the surface of barium sulfate and titanium dioxide.

Further, the silane coupling agent in the above step (2) is 1-2‰ of the sum of the mass of wollastonite, barium sulfate and titanium dioxide, so as to achieve coating on the surface of the composite material.

Further, the mill speed of the above-mentioned wet vertical grinder is 200-250r/min.

Further, the above-mentioned titanium dioxide is rutile titanium dioxide. Titanium dioxide is divided into rutile type and anatase type. The refractive index of rutile type is 2.76, and that of anatase type is 2.55. The gloss prepared by rutile type is higher, and the weather resistance and chemical resistance of rutile type are better. It can adapt to a wider range of use environments.

A kind of product of the preparation method of composite material for polypropylene modification, it is characterized in that, on the surface of wollastonite, there is a composite coating layer formed by titanium dioxide and barium sulfate, and the surfaces of titanium dioxide and barium sulfate are equipped with Silicone coating.

Further, the coating rate of the composite coating layer of wollastonite is 98-100%, and the coating rate of the organic silicon coating layer of titanium dioxide and barium sulfate is 98-100%. The use of silicone coating can maximize the compatibility between the three fillers, and the higher the coating rate, the better the compatibility effect, and the better the performance of each particle. maximum effect.

Further, the aspect ratio of the wollastonite is (15-20):1. The larger the aspect ratio of wollastonite, the larger the steric hindrance space between the two particles that can be realized, that is, the better coating of the composite coating layer formed by titanium dioxide powder and barium sulfate can be achieved. The surface of wollastonite forms a continuous and uniform coating effect.

The present invention has the following beneficial technical effects:

The present invention organically combines wollastonite, titanium dioxide and barium sulfate through a mechanochemical method, so that titanium dioxide and barium sulfate are evenly distributed on wollastonite whiskers, and a high weather resistance, high gloss, Composite reinforcing material with high chemical stability; the refractive index of a single barium sulfate is 1.67, and that of a single wollastonite is 1.63. The refractive index of this product is greater than or equal to 2, and the gloss is greatly improved; the selected Both barium sulfate and wollastonite can resist acid and alkali, and wollastonite has good fiber structure, high aspect ratio and corrosion resistance, which can improve the mechanical strength of polypropylene such as tensile resistance and bending resistance. After surface modification The high-quality titanium dioxide can provide good heat resistance, weather resistance and high decolorization power. The high-purity ultra-fine barium sulfate has a dense crystal form and excellent chemical stability. It can improve the surface gloss and processing fluidity of polypropylene. , using this product to fill modified polypropylene, its heat resistance temperature can be increased by 20-30 ° C, tested in the thermal oxygen aging experiment at 120 ° C and 1000 minutes, the product color is consistent with the sample prepared by pure titanium dioxide, no color The change.

【Description of drawings】

Fig. 1 is a flow chart of steps of the present invention.

【detailed description】

The present invention will be further described below in conjunction with specific embodiments.

The embodiments provided below are not intended to limit the scope of the present invention, and the described steps are not intended to limit the execution sequence thereof. Obvious improvements made by those skilled in the art in combination with existing common knowledge also fall within the scope of protection required by the present invention.

Embodiment one

A kind of preparation method of composite material for polypropylene modification, is characterized in that, comprises the following steps:

(1) Adjust the 400-600 mesh wollastonite powder with water to form a slurry with a mass concentration of 50%-60%, and add sodium stearate as a dispersant while preparing the slurry, and the addition amount is 2‰ of the dry wollastonite powder mass , to improve the dispersibility and grindability of the slurry.

(2) Mix 400-600 mesh barium sulfate and 300-400 mesh rutile titanium dioxide with water at a mass ratio of 4:1 to form a composite slurry with a mass concentration of 65%, and add 3% sodium stearate as a dispersant at the same time , Add 2‰ of D-7080 silane coupling agent as a dispersant and surface modifier.

(3) Feed the titanium dioxide-barium sulfate composite slurry prepared in (2) into the wet vertical stirring mill through a diaphragm pump, the mill speed is 200r/min, and the content of the slurry below 2 μm is controlled to be higher than 95 %. The crystal lattice of ultrafine barium sulfate and rutile titanium dioxide continues to break during the grinding process, the surface energy continues to increase, and the particles adsorb each other. Under the action of the silane coupling agent, the co-coating is completed to form a titanium dioxide-barium sulfate composite. For powder, put the composite slurry into the slurry storage tank, stir and store it for later use.

(4) the wollastonite slurry prepared in (2) is fed into the wet vertical grinder by a diaphragm pump, the mill speed is 200r/min, the rotating speed of the diaphragm pump is adjusted to control the wollastonite particle size, While grinding the wollastonite, put the titanium dioxide-barium sulfate composite slurry prepared in (3) into the vertical stirring mill at a mass ratio of 10:1 to the wollastonite, and add 1‰ D-7080 silane coupling agent for further organic coating, so as to obtain the final composite material slurry.

(5) The composite slurry obtained in (4) is fed into the flash dryer through a diaphragm pump, and the hot air inlet temperature is controlled at 380° C. to obtain a composite material dry powder;

(6) The composite material dry powder obtained in (5) is dispersed and depolymerized by a disintegrator, and then classified by a cyclone, and the unqualified particles are returned to the depolymerizer for depolymerization, and the qualified particles enter the packaging system.

A kind of product that obtains according to above-mentioned method, has the compound coating layer that titanium dioxide and barium sulfate form on the surface of wollastonite, and the surface of described titanium dioxide and barium sulfate is equipped with organosilicon coating layer; Above-mentioned wollastonite The coating rate of the composite coating layer is 98-100%, and the coating rate of the organic silicon coating layer of the titanium dioxide and barium sulfate is 98-100%; the aspect ratio of the above-mentioned wollastonite is (15- 20): 1. The refractive index of this product is 2.12, and the gloss is greatly improved; when this product is filled with modified polypropylene, its heat resistance temperature can be increased by 20-30°C, and it is tested in the thermal oxygen aging experiment at 120°C for 1000 minutes. The color of the product is consistent with the spline prepared by pure titanium dioxide, and there is no color change.

The relevant detection of the product has been added to the following table:

Embodiment two

A kind of preparation method of composite material for polypropylene modification, is characterized in that, comprises the following steps:

(3) Adjust the 400-600 mesh wollastonite powder with water into a slurry with a mass concentration of 50%-60%, and add sodium stearate as a dispersant while preparing the slurry, and the addition amount is 3‰ of the wollastonite dry powder mass , to improve the dispersibility and grindability of the slurry.

(4) Mix 400-600 mesh barium sulfate and 300-400 mesh rutile titanium dioxide with water at a mass ratio of 5:1 to form a composite slurry with a mass concentration of 68%, and add 3% sodium stearate as a dispersant at the same time , Add 2‰ of D-7080 silane coupling agent as a dispersant and surface modifier.

(3) Feed the titanium dioxide-barium sulfate composite slurry prepared in (2) into the wet vertical stirring mill through a diaphragm pump, the mill speed is 200r/min, and the content of the slurry below 2 μm is controlled to be higher than 95 %. The crystal lattice of ultrafine barium sulfate and rutile titanium dioxide continues to break during the grinding process, the surface energy continues to increase, and the particles adsorb each other. Under the action of the silane coupling agent, the co-coating is completed to form a titanium dioxide-barium sulfate composite. For powder, put the composite slurry into the slurry storage tank, stir and store it for later use.

(4) the wollastonite slurry prepared in (2) is fed into the wet vertical grinder by a diaphragm pump, the mill speed is 200r/min, the rotating speed of the diaphragm pump is adjusted to control the wollastonite particle size, While grinding the wollastonite, put the titanium dioxide-barium sulfate composite slurry prepared in (3) into the vertical stirring mill at a mass ratio of 11:1 to the wollastonite, and add 1.5‰ D-7080 silane coupling agent for further organic coating, so as to obtain the final composite material slurry.

(5) The composite slurry obtained in (4) is fed into the flash dryer through a diaphragm pump, and the hot air inlet temperature is controlled at 370° C. to obtain a composite material dry powder;

(6) The composite material dry powder obtained in (5) is dispersed and depolymerized by a disintegrator, and then classified by a cyclone, and the unqualified particles are returned to the depolymerizer for depolymerization, and the qualified particles enter the packaging system.

A kind of product that obtains according to above-mentioned method, has the compound coating layer that titanium dioxide and barium sulfate form on the surface of wollastonite, and the surface of described titanium dioxide and barium sulfate is equipped with organosilicon coating layer; Above-mentioned wollastonite The coating rate of the composite coating layer is 98-100%, and the coating rate of the organic silicon coating layer of the titanium dioxide and barium sulfate is 98-100%; the aspect ratio of the above-mentioned wollastonite is (15- 20): 1. The refractive index of this product is 2.11, and the gloss is greatly improved; when this product is filled with modified polypropylene, its heat-resistant temperature can be increased by 20-30°C, tested in the thermal oxygen aging experiment at 120°C and 1000 minutes, its The color of the product is consistent with the spline prepared by pure titanium dioxide, and there is no color change. The relevant detection of the product has been added to the following table:

Test items Test results CaSiO ₃ content% in wollastonite 92.4 _TiO2 content in titanium dioxide % 94.5 BaSO ₄ content in natural barium sulfate % 97.2 wollastonite aspect ratio 19:1 Wollastonite D ₅₀ μm 3.7 Coupling agent coverage% 98.3 Barium sulfate coated titanium dioxide coating rate% 98.1 Titanium dioxide and barium sulfate coated wollastonite coating rate% 98.7

Embodiment three

A kind of preparation method of composite material for polypropylene modification, is characterized in that, comprises the following steps:

(5) Adjust the 400-600 mesh wollastonite powder with water into a slurry with a mass concentration of 50%-60%, and add sodium stearate as a dispersant while preparing the slurry, and the addition amount is 5‰ of the wollastonite dry powder mass , to improve the dispersibility and grindability of the slurry.

(6) Mix 400-600 mesh barium sulfate and 300-400 mesh rutile titanium dioxide with water at a mass ratio of 6:1 to form a composite slurry with a mass concentration of 70%, and add 3% sodium stearate as a dispersant at the same time , Add 2‰ of D-7080 silane coupling agent as a dispersant and surface modifier.

(3) Feed the titanium dioxide-barium sulfate composite slurry prepared in (2) into the wet vertical stirring mill through a diaphragm pump, the mill speed is 250r/min, and the content of the slurry below 2 μm is controlled to be higher than 98 %. The crystal lattice of ultrafine barium sulfate and rutile titanium dioxide continues to break during the grinding process, the surface energy continues to increase, and the particles adsorb each other. Under the action of the silane coupling agent, the co-coating is completed to form a titanium dioxide-barium sulfate composite. For powder, put the composite slurry into the slurry storage tank, stir and store it for later use.

(4) the wollastonite slurry prepared in (2) is fed into the wet vertical grinder by a diaphragm pump, the mill speed is 250r/min, the rotating speed of the diaphragm pump is adjusted to control the wollastonite particle size, While grinding the wollastonite, feed the titanium dioxide-barium sulfate composite slurry prepared in (3) into the vertical stirring mill at a mass ratio of 12:1 to the wollastonite, and add 2‰ D-7080 silane coupling agent for further organic coating, so as to obtain the final composite material slurry.

(5) Feed the composite slurry obtained in (4) into a flash dryer through a diaphragm pump, and control the hot air inlet temperature at 390° C. to obtain a composite material dry powder;

(6) The composite material dry powder obtained in (5) is dispersed and depolymerized by a disintegrator, and then classified by a cyclone, and the unqualified particles are returned to the depolymerizer for depolymerization, and the qualified particles enter the packaging system.

A kind of product that obtains according to above-mentioned method, has the compound coating layer that titanium dioxide and barium sulfate form on the surface of wollastonite, and the surface of described titanium dioxide and barium sulfate is equipped with organosilicon coating layer; Above-mentioned wollastonite The coating rate of the composite coating layer is 98-100%, and the coating rate of the organic silicon coating layer of the titanium dioxide and barium sulfate is 98-100%; the aspect ratio of the above-mentioned wollastonite is (15- 20): 1. The refractive index of this product is 2.13, and the gloss is greatly improved; when this product is filled with modified polypropylene, its heat-resistant temperature can be increased by 20-30°C, tested in the thermal oxygen aging test at 120°C for 1000 minutes, its The color of the product is consistent with the spline prepared by pure titanium dioxide, and there is no color change. The relevant detection of the product has been added to the following table:

Test items Test results CaSiO ₃ content% in wollastonite 92.4 _TiO2 content in titanium dioxide % 94.5 BaSO ₄ content in natural barium sulfate % 97.2 wollastonite aspect ratio 19:1 Wollastonite D ₅₀ μm 3.0 Coupling agent coverage% 98.8 Barium sulfate coated titanium dioxide coating rate% 98.5 Titanium dioxide and barium sulfate coated wollastonite coating rate% 99.2

Claims (10)

1. the preparation method of a polypropylene modification composite, it is characterised in that comprise the following steps:

(1) by the slurry of wollastonite in powder use water furnishing mass concentration 50%-60% of 400-600 mesh, sodium stearate conduct is added Dispersant；

(2) by the titanium dioxide of the barium sulfate of 400-600 mesh and 300-400 mesh in mass ratio for (4-6): 1 to be made into quality with water dense The composite mortar of degree 65-70%, adds sodium stearate and silane coupler as dispersant and coating material；

(3) the titanium dioxide barium sulfate composite mortar prepared in (2) is fed in Wet vertical grinder wet grinding to 3000 ～4000 mesh；

(4) the wollastonite slurry prepared in (1) is fed in Wet vertical grinder, add by (3) prepare titanium dioxide- Barium sulfate composite mortar, the mass ratio of titanium dioxide-barium sulfate and wollastonite is (10-12): 1, then adds silane coupler and carry out Cladding, mean diameter D of wet grinding to wollastonite particles₅₀For 2.0-2.5 μm；

(5) composite mortar obtained in (4) feeding flash dryer, hot wind inlet temperature controls, at 370-390 DEG C, to be answered Condensation material dry powder；

(6) the composite dry powder that (5) obtain is broken up depolymerization, then through cyclone classified process, collect the powder body of 2500-3000 mesh Obtain composite products.

The preparation method of polypropylene modification composite the most according to claim 1, it is characterised in that described step (1) sodium stearate addition is wollastonite in powder quality 2 ‰-5 ‰.

The preparation method of polypropylene modification composite the most according to claim 1, it is characterised in that described step (2) sodium stearate addition is barium sulfate and the 3-5% of titanium dioxide quality sum.

The preparation method of polypropylene modification composite the most according to claim 1, it is characterised in that described step (2) silane coupler is barium sulfate and the 2-4 ‰ of titanium dioxide quality sum.

The preparation method of polypropylene modification composite the most according to claim 1, it is characterised in that described step (2) silane coupler is wollastonite, barium sulfate and the 1-2 ‰ of titanium dioxide quality sum.

The preparation method of polypropylene modification composite the most according to claim 1, it is characterised in that described wet method is stood The mill speed of formula grinder is 200-250r/min.

The preparation method of polypropylene modification composite the most according to claim 1, it is characterised in that described titanium dioxide For Rutile type titanium dioxide.

8. a product for the preparation method of the polypropylene modification composite as described in any one of claim 1-7, it is special Levy and be, the surface of wollastonite possesses the compound coating layer that titanium dioxide is formed with barium sulfate, described titanium dioxide and barium sulfate Surface be provided with silicone covering layer.

The product of the preparation method of polypropylene modification composite the most according to claim 8, it is characterised in that described The clad ratio of the compound coating layer of wollastonite is 98-100%, the clad ratio of the silicone covering layer of described titanium dioxide and barium sulfate For 98-100%.

The product of the preparation method of polypropylene modification composite the most according to claim 8, it is characterised in that institute The draw ratio stating wollastonite is (15-20): 1.