TW201733762A - Preparation method of polymer blending with master batch that is allowed to have the polymer powder and the inorganic powder evenly dispersed in it, and then delivers the premixed powder to a twin screw extruder to have it be palletized after melting, mixing, and extruding - Google Patents

Abstract

The invention utilizes a powder heating and mixing of a polymer powder and an inorganic powder to obtain a premixed powder that is allowed to have the polymer powder and the inorganic powder evenly dispersed in it, and then delivers the premixed powder to a twin screw extruder to have it be palletized after melting, mixing, and extruding. It reduces the heating times of polymer material and, at the same time, increases the dispersibility of the inorganic powder and the polymer material and the thermal stability of the polymer.

Description

Preparation method of polymer blending masterbatch

The invention relates to a preparation method of a blending material, in particular to a preparation method of a polymer blend masterbatch for adding to a polymer matrix.

Polymer products, such as plastic bags, shopping bags, industrial films, packaging materials or containers, may be added with inorganic powders directly blended with the polymer matrix, such as calcium carbonate, to improve the thermal properties and dimensional stability of the product. It can improve printability, reduce heat of combustion, and reduce secondary pollution.

The inorganic powder conventionally used for adding to the polymer matrix is first blended with the polymer to form a high concentration of the masterbatch, and then the blended masterbatch is blended with the pre-blended polymer matrix. Refining, and finally through the process of blowing bags or squeezing to obtain the desired finished products, such as plastic bags or plastic cups. Generally, the masterbatch is prepared by mixing the polymer masterbatch with the inorganic powder, heating to a melting temperature of the polymer masterbatch, and allowing the polymer masterbatch to be melted and then kneaded with the inorganic powder, and then cooled. The kneaded mixture is diced and pulverized, and then sent to a single screw extruder or a double cone extruder to press granulation to obtain the above-mentioned blended masterbatch for blending.

However, in the preparation process of the above-mentioned blended masterbatch, since the polymer material has to be heated twice (the first heating is in the kneading process and the second heating is in the extruding machine), the polymer is heated many times, so The stability of the polymer is poor. In addition, there is a disadvantage that local heating unevenness is likely to occur during the heating process. Therefore, during the stirring process, the polymer located in the dead zone of the stirring tank is liable to be coked.

Accordingly, it is an object of the present invention to provide a method of preparing a polymer blend masterbatch.

Thus, the preparation method of the polymer blend masterbatch of the present invention comprises a mixing step, a cooling step, and an extrusion granulation step.

The mixing step is to put a polymer powder and an inorganic powder into a mixing tank, and simultaneously increase the temperature in the mixing tank to be greater than 100 ° C and less than the melting point of the polymer powder. The polymer powder and the inorganic powder are mixed by powder heat to obtain a premixed powder.

This cooling step is to cool the premixed powder to a temperature of not lower than 40 °C.

The extrusion granulation step is to feed the cooled premixed powder into a twin-screw extrusion granulation device, heat-melt and mix the pre-mixed powder, and then granulate it to obtain a polymer blending mother. material.

The effect of the invention is that the polymer powder is first mixed with the inorganic powder by powder hot mixing, and then the mixed premixed powder is sent to a biaxial extruder for melt-kneading, and then granulated and reduced. The frequency at which the polymer material is heated at a high temperature can simultaneously improve the dispersibility of the inorganic powder and the polymer powder and the thermal stability of the polymer.

Referring to FIG. 1, an embodiment of a method for preparing a polymer blend masterbatch of the present invention comprises: a pre-pulverizing step 21, a mixing step 22, a cooling step 23, and an extrusion granulation step 24.

This pre-pulverization step 21 is a process of pulverizing a polymer raw material into a polymer powder.

Specifically, in general, after the completion of the polymerization, the polymer raw material is granulated to become a polymer particle having a large particle diameter. However, since the polymer particles at this time have a large particle diameter, they are not suitable for being directly mixed with the inorganic powder to obtain a uniform mixed body. Therefore, the pre-pulverizing step 21 of the present invention is originally large. The polymer material of the particle size is pulverized into a polymer powder having a particle diameter of not more than 1.0 mm to facilitate the subsequent process. However, it is to be noted that, when the polymer material for blending with the inorganic powder is sufficiently finer in the particle diameter of the primary particles, the pre-pulverization step 21 need not be performed.

In addition, it is to be noted that the polymer blend masterbatch of the present invention is used for blending in different polymer matrices to make different plastic finished products. Therefore, the material selection of the polymer raw material of the polymer blending master batch is matched with the polymer material having the same pre-blended polymer matrix or good compatibility, and is not particularly limited. For example, the polymer matrix to be blended later is PE (Polyethylene), PP (Polypropylene), HDPE (High-density polyethylene), or PLA (Polyactic acid). Then, the polymer raw material of the blending masterbatch may be respectively selected from PE, PP, HDPE, PLA, or a polymer raw material having good compatibility with the polymer matrix.

In the mixing step 22, the polymer powder and the inorganic powder obtained by the pre-pulverization step 21 are weighed according to the demand ratio, and then placed in a mixing tank to perform hot mixing of the powder to obtain a mixture. Premixed powder.

The inorganic powder is selected from the group consisting of calcium carbonate, talc, barium sulfate and the like, and may be a mixture of one or more kinds alone. The content of the inorganic powder is from 40 to 85% by weight based on 100% by weight of the polymer powder and the inorganic powder. The purpose of the inorganic powder is to reduce the amount of the polymer material to reduce the cost, and it can also be used to improve the dimensional stability, thermal properties, and printability of the subsequently obtained finished product.

Specifically, in the mixing step 22, the polymer powder and the inorganic powder are weighed in proportion and placed in a mixing tank, and the temperature in the mixing tank is controlled according to the mixing time. The polymer powder and the inorganic powder are subjected to powder heat mixing by rising to a temperature greater than 100 ° C and less than the melting point of the polymer powder. The purpose of the hot mixing is because the polymer powder has a small particle size and a high hygroscopicity, so it is easier to agglomerate during the mixing process. Therefore, the stirring temperature is increased to more than 100 ° C and is less than Between the melting point temperatures of the polymer powders, in addition to being mixable, the water vapor absorbed by the polymer powder can be evaporated to avoid agglomeration, and the dispersion uniformity of the premixed powder can be further improved.

In order to prevent the excessive temperature from affecting the properties of the polymer and to avoid melting of the polymer surface to affect the dispersibility, preferably, the mixing step 22 is controlled at 100 to 120 °C. More preferably, the mixing step 22 is to maintain the mixing speed of the mixing tank at 700-800 rpm, and the powder temperature in the mixing tank is gradually increased to 100-120 during the stirring process by high-speed mixing. Between °C. The use of high-speed mixing to raise the temperature can avoid heating by the heater, because the polymer is unevenly heated, resulting in the disadvantage of coking.

More specifically, the mixing step 22 is to maintain the mixing speed of the mixing tank at 700-800 rpm, and the powder temperature in the mixing tank is raised to 100-120 ° C during the stirring process by high-speed mixing. Then, the mixture is continuously stirred at the temperature for about 30 seconds to 2 minutes, and the moisture of the polymer powder can be sufficiently evaporated to obtain the premixed powder.

Then, the cooling step 23 is performed, the premixed powder in the mixing tank is unloaded to a cold mixing tank, and the cold mixing tank is controlled to be mixed at a speed of not more than 500 rpm. The premixed powder in the cold mix tank is cooled to a temperature not lower than 40 °C. Preferably, the cooling step 23 is to cool the premixed powder to between 50 ° C and 60 ° C.

Finally, the extrusion granulation step 24 is carried out, and the cooled premixed powder is sent to a twin screw extrusion granulation device, and the premixed powder is heated and melted and mixed, and then granulated to obtain a high. Molecular blending masterbatch.

In detail, the extrusion granulation step 24 is to feed the premixed powder cooled by the cooling step 23 into a twin screw extruder, and the premixed powder is heated and melted in the twin screw extruder. After being mixed again, the mixture is extruded, and then granulated and cooled to obtain the masterbatch for polymer blending. Since the twin-screw extruder is a well-known equipment in the technical field, and the extrusion and granulation of the high-mole material by the twin-screw extruder is a process commonly used in the technical field, the relevant operating conditions and parameters are not further described herein.

In the present invention, the polymer material for blending the master batch is powdered, the polymer powder is first mixed with the inorganic material, and the premixed powder obtained after the mixing is sent to the twin-screw extrusion. The machine is melt-kneaded and then granulated. Since the polymer raw material is preliminarily pulverized to form a polymer powder having a small particle diameter, and the mixing step 22 is a powder hot mixing of the polymer powder and the inorganic powder, the two powders can be effectively improved. Dispersion uniformity of the body, and it can be avoided that the inorganic powder is directly mixed with the molten polymer raw material, and there is a disadvantage that the inorganic powder agglomerates are not easily dispersed; in addition, since the polymer material is only in the double When the shaft is granulated, the granulation is subjected to high heat, so that the number of times the polymer material is heated can be reduced, and the dispersibility of the inorganic powder and the polymer material and the thermal stability of the polymer can be simultaneously improved.

When the polymer blend masterbatch prepared by the preparation method of the present invention is to be blended with the polymer matrix, the polymer may be blended with the masterbatch and the polymer according to the original preparation process of the desired product. The matrix can be melt blended and processed.

Referring to Figures 2 and 3, Figure 2 is a polymer blend masterbatch (PE/CaCO ₃ = 25 wt% / 75 wt%) prepared by the preparation method of this embodiment of the present invention, with a polymer matrix (PE) in weight percent 20 wt%: 80 wt% of the film after blending, and then through a blow bag. 3 is a polymer blend masterbatch obtained by a conventional method (PE/CaCO ₃ = 25 wt% / 75 wt%): a polymer raw material (PE) and an inorganic powder (CaCO ₃ ) are mixed by melt kneading. After cooling and pulverizing, it is obtained by granulation by a uniaxial extruder. And the polymer blended masterbatch was mixed with a molecular matrix (PE) in a ratio of 20% by weight: 80% by weight, and then a film formed by blowing the bag. It can be clearly seen from Fig. 3 that the polymer blend masterbatch prepared by the conventional method has poor dispersibility, and therefore, the film obtained by subsequent blending with the polymer matrix obviously has agglomeration of inorganic powder. The undispersed particles are dispersed in the film; in contrast, the polymer blend masterbatch prepared by the preparation method of the present invention exhibits better dispersibility after blending with the molecular matrix because of better dispersibility, so The finally obtained film, as shown in FIG. 2, the inorganic powder can be sufficiently dispersed in the polymer matrix to have better uniformity.

In summary, the present invention utilizes the powdered hot polymer powder and the inorganic powder to be mixed with the inorganic powder to improve the dispersion uniformity of the powder, and then the premixed powder obtained after the mixing is sent to the mixture. The biaxial extruder is melt-kneaded and then granulated, which not only improves the dispersibility of the inorganic powder and the polymer material, but also reduces the number of times the polymer material is heated, and simultaneously improves the thermal stability of the polymer material. It is indeed possible to achieve the purpose of the invention.

However, the above is only the embodiment of the present invention, and the scope of the invention is not limited thereto, and all the equivalent equivalent changes and modifications according to the scope of the patent application and the patent specification of the present invention are still The scope of the invention is covered.

21‧‧‧Pre-crushing step
22‧‧‧ Mixing step
23‧‧‧ Cooling steps
24‧‧‧Extrusion granulation step

Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: Figure 1 is a textual flow diagram of an embodiment of a method for preparing a polymer blend masterbatch of the present invention; a film obtained by blending a polymer blend masterbatch prepared in this embodiment of the present invention with a polymer matrix; and FIG. 3 illustrates blending a polymer blend masterbatch prepared by a conventional method with a polymer matrix The film produced afterwards.

21‧‧‧Pre-crushing step

22‧‧‧ Mixing step

23‧‧‧ Cooling steps

24‧‧‧Extrusion granulation step

Claims (7)

A method for preparing a polymer blend masterbatch, comprising: a mixing step, placing a polymer powder and an inorganic powder into a mixing tank, and simultaneously increasing the temperature in the mixing tank to a temperature Between greater than 100 ° C and less than the melting point of the polymer powder, the polymer powder and the inorganic powder are powder-mixed to obtain a pre-mixed powder; a cooling step, the pre-mixing The powder is cooled to a temperature not lower than 40 ° C; and an extrusion granulation step, the cooled premixed powder is sent to a twin screw extrusion granulation device, and the premixed powder is heated and melted and mixed. Granulation is carried out to obtain a polymer blend masterbatch. The method for preparing a polymer blend masterbatch according to Item 1, wherein the mixing step is to raise the temperature in the mixing tank to between 100 and 120 °C. The method for preparing a polymer blend masterbatch according to Item 2, wherein the mixing step is to maintain the mixing speed of the mixing tank at 700-800 rpm, and the mixing tank is used in the mixing tank by high-speed mixing. The temperature rises to between 100 and 120 ° C and is continuously stirred at this temperature for 30 seconds to 2 minutes. The method for preparing a polymer blend masterbatch according to Item 1, wherein the cooling step is to send the premixed powder to a cold mixing tank, and the cold mixing tank is controlled to have a mixing speed of not more than 500 rpm. Under the condition, the premixed powder in the cold mixing tank is cooled to 50 to 60 ° C by low-speed mixing. The method for preparing a polymer blend masterbatch according to claim 1, further comprising a pre-pulverizing step performed before the mixing step, grinding a polymer raw material into a polymer powder having a particle diameter of not more than 1.0 mm. In the mixing step, the polymer powder obtained by the pre-pulverization step and the inorganic powder are weighed and placed in the mixing tank. The method for preparing a polymer blend masterbatch according to Item 1, wherein the mixing step is such that the content of the inorganic powder is 100% by weight based on the weight of the polymer powder and the inorganic powder. The polymer powder is mixed with 40 to 85 wt% of the inorganic powder. The method for preparing a polymer blend master batch according to Item 1, wherein the inorganic powder is selected from the group consisting of calcium carbonate, talc, barium sulfate, or a combination thereof.