Preparation method for improving toughness of HDPE (high-density polyethylene) mute master batch

Abstract

The invention discloses a preparation method for improving toughness of HDPE (high-density polyethylene) mute master batch, and belongs to the technical field of plastics. The preparation method comprises the following steps: a, preparing the following raw materials in parts by mass: 90-100 parts of HDPE, 10-30 parts of nano calcium carbonate, 25-40 parts of barium sulfate, 1-2 parts of stearic acid and 8-10 parts of titanium dioxide; and b, uniformly mixing the raw materials, and carrying out extrusion granulation to obtain the high-toughness HDPE mute master batch with the density of 1.2-1.3 g / cm < 3 >. When the master batch prepared by the method is used for manufacturing a pipe, the tensile strength of the pipe is not reduced, the toughness of the pipe is improved, the mute effect is ensured, and the requirements of customers are met.

Description

Technical Field

[0001] This invention relates to the field of plastics technology, and more specifically, to a method for preparing HDPE silent masterbatch with improved toughness. Background Technology

[0002] In recent years, HDPE (high-density polyethylene) silent pipe systems have gained increasing popularity among customers and have been widely used in building drainage. However, the brittleness of HDPE silent pipes has always been a focus of attention, especially when the product density is between 1.2 and 1.3 g / cm³. 3 While achieving a quiet operation, HDPE pipes often have an elongation at break of less than 30%, making them prone to cracking, especially in environments with large temperature differences. To improve product toughness, the most common solution is to reduce the density of the masterbatch used for noise reduction; however, this significantly reduces the noise reduction effect. Furthermore, the strength and toughness of most materials are relative, making it difficult to improve toughness without compromising tensile strength. Therefore, there is an urgent need to address the issue of achieving both quiet operation, toughness, and tensile strength in HDPE pipes to enhance their market competitiveness. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing HDPE silent masterbatch with improved toughness. Pipes prepared from this masterbatch can improve their toughness and ensure the silent effect without reducing the tensile strength of the pipe, thus meeting customer needs.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for preparing HDPE silent masterbatch with improved toughness includes the following steps:

[0006] a. Prepare the following raw materials by weight: 90-100 parts HDPE, 10-30 parts nano calcium carbonate, 25-40 parts barium sulfate, 1-2 parts stearic acid, and 8-10 parts titanium dioxide.

[0007] b. After mixing all raw materials, extrude and granulate to obtain a density of 1.2–1.3 g / cm³. 3 High-toughness HDPE silent masterbatch.

[0008] The present invention is further configured such that, in step b, each raw material is mixed evenly by a mixer at a mixing temperature of 40–60°C.

[0009] The present invention is further configured such that the mixing machine speed is 400-500 rpm and the mixing time is 1.5-2 min.

[0010] The present invention is further configured such that, in step b, a parallel twin-screw extruder is used for extrusion granulation; the extrusion granulation process conditions are: barrel temperature 180-190℃, die temperature 200-210℃, screw speed 400-450 rpm, feeding speed 30-45 rpm, and cutting speed 500-600 rpm.

[0011] The present invention further specifies that the HDPE density is 0.94–0.96 g / cm³. 3 The melt index measured at 190℃ and 5kg load was 18-21g / 10min.

[0012] The present invention is further configured such that the barium sulfate particle size is 400-500 mesh.

[0013] The present invention is further configured such that the melt index of the HDPE silent masterbatch, measured at 190°C and 5kg load, is 0.4 to 0.8 g / 10min.

[0014] The present invention is further configured such that the HDPE silent masterbatch is made from the following raw materials in parts by weight: 100 parts HDPE, 12-17 parts nano calcium carbonate, 25-35 parts barium sulfate, 1-2 parts stearic acid, and 8-10 parts titanium dioxide.

[0015] The present invention is further configured such that the HDPE silent masterbatch is made from the following raw materials in parts by weight: 100 parts HDPE, 16.5 parts nano calcium carbonate, 27.6 parts barium sulfate, 2 parts stearic acid, and 8 parts titanium dioxide.

[0016] In summary, the present invention has the following beneficial effects:

[0017] By reducing the content of nano-calcium carbonate and increasing the content of barium sulfate, the overall filler content in the formulation is reduced, resulting in a density of 1.2–1.3 g / cm³. 3 The HDPE noise reduction masterbatch is simple, effective, and easy to produce. Using this noise reduction masterbatch as raw material, pipes can be directly extruded and manufactured. This not only ensures the noise reduction effect of the pipes, but also greatly improves their toughness without reducing their tensile strength. The elongation at break is increased from the conventional 30% to more than 300%. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The density of the HDPE silent masterbatch of this invention is 1.2-1.3 g / cm³. 3 The melt index is 0.4–0.8 g / 10 min (190 °C, 5 kg), and it is prepared by the following method:

[0020] a. Prepare the following raw materials in parts by weight: 90-100 parts HDPE, 10-30 parts nano-calcium carbonate, 25-40 parts barium sulfate (particle size 400-500 mesh), 1-2 parts stearic acid, and 8-10 parts titanium dioxide; the density of HDPE is 0.94-0.96 g / cm³. 3 The melt index is 18-21 g / 10 min (190℃, 5 kg).

[0021] b. Mix all raw materials thoroughly using a mixer (mixing temperature 40-60℃, mixer speed 400-500 rpm, mixing time 1.5-2 min), then extrude and granulate using a parallel twin-screw extruder to obtain high-toughness HDPE silent masterbatch. The extrusion granulation process conditions are: barrel temperature 180-190℃, die temperature 200-210℃, screw speed 400-450 rpm, feed speed 30-45 rpm, and cutting speed 500-600 rpm.

[0022] The specific implementation method is as follows:

[0023] Example 1

[0024] a. Prepare the following raw materials by weight: 100 parts HDPE (density 0.95 g / cm³) 3 The following components were used: melt index 20 g / 10 min (190℃, 5 kg), nano calcium carbonate 11.5 parts, barium sulfate (particle size 400-450 mesh) 29.3 parts, stearic acid 2 parts, and titanium dioxide 8 parts.

[0025] b. Mix all raw materials thoroughly using a mixer (mixing temperature 48℃, mixer speed 430 rpm, mixing time 1.7 min), then extrude and granulate using a parallel twin-screw extruder to obtain high-toughness HDPE silent masterbatch. The extrusion granulation process conditions are: barrel temperature 183℃, die temperature 205℃, screw speed 420 rpm, feed speed 33 rpm, and cutter speed 530 rpm.

[0026] Comparative Example 1

[0027] The formulation of Comparative Example 1 was as follows: 100 parts HDPE, 66 parts nano-calcium carbonate, 2 parts stearic acid, and 8 parts titanium dioxide. It was prepared according to the method of Example 1.

[0028] Comparative Example 2

[0029] The formulation of Comparative Example 1 was as follows: 100 parts HDPE, 33 parts nano-calcium carbonate, 16.5 parts barium sulfate, 2 parts stearic acid, and 8 parts titanium dioxide. It was prepared according to the method of Example 1.

[0030] Comparative Example 3

[0031] The formulation of Comparative Example 1 was as follows: 100 parts HDPE, 22 parts nano-calcium carbonate, 22 parts barium sulfate, 2 parts stearic acid, and 8 parts titanium dioxide. It was prepared according to the method of Example 1.

[0032] The masterbatches prepared in Example 1 and Comparative Examples 1-3 were used as raw materials for extrusion molding to produce pipes of the same specifications (the pipe preparation method was as follows: both the inner and outer layers used materials with a density of 0.95 g / cm³). 3 HDPE raw material with a melt index of 20 g / 10 min (190℃, 5 kg) was used. The intermediate layer used HDPE silent masterbatch prepared in the examples or comparative examples. The inner, outer, and intermediate layer raw materials were placed in three screw-connected extruders and melted at 200℃ to obtain inner layer melt, middle layer melt, and outer layer melt, respectively. The inner layer melt, middle layer melt, and outer layer melt were fed into the three feed barrels of a three-layer co-extrusion extruder for three-layer co-extrusion to produce a three-layer co-extruded silent composite pipe with an outer diameter De of 75 mm and a wall thickness of 3.8 mm. The volume ratio of the inner, middle, and outer layer melts was 1.5:7:1.5. The three-layer co-extrusion conditions were: barrel temperature 200℃, die outlet temperature 190℃, screw speed 50 r / min, feed speed 30 r / min, traction speed 270 r / min, and vacuum control at 0.07 MPa during extrusion. The performance of each pipe was tested, and the results are shown in the table below:

[0033] Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Nano calcium carbonate content in the formula (%) 37.5 20.7 14.3 7.6 Barium sulfate content in the formula (%) 0 10.3 14.3 19.4 <![CDATA[Masterbatch density g / cm 3 > 1.3 1.29 1.25 1.23 Pipe tensile strength (MPa) 19.5 20.0 20.3 20.7 Pipe elongation at break % 30 85 225 300 Pipe drainage noise / decibels ＜40 ＜40 ＜40 ＜40

[0034] As shown in the table above, Comparative Example 1 uses nano-calcium carbonate as filler, and the density of the HDPE noise-reducing masterbatch reaches 1.3 g / cm³. 3 However, the resulting pipes have extremely low toughness, with an elongation at break of less than 30%, and the products exhibit brittle cracking. This invention reduces the overall filler content in the masterbatch formula by decreasing the content of nano-calcium carbonate and increasing the content of barium sulfate, thereby improving the toughness of the pipes without reducing their noise reduction effect.

[0035] Further testing revealed that adjusting the content of nano-calcium carbonate in the formulation of Comparative Example 1 resulted in a masterbatch density of 1.2 g / cm³. 3 At that time, although the pipe could achieve a silent effect, its elongation at break was only 29.3%; by adjusting the content of nano-calcium carbonate in the formula of Comparative Example 3, the density of the resulting masterbatch was 1.17 g / cm³. 3At that time, although the pipe's elongation at break was 305%, it did not achieve a silent effect (noise level was 51 decibels); when the formula was: HDPE 90-100 parts, nano-calcium carbonate 10-30 parts, stearic acid 1-2 parts, titanium dioxide 8-10 parts, and barium sulfate 44 parts, while controlling the masterbatch density at 1.2-1.3 g / cm³, the noise level was lowered. 3 At that time, the resulting pipes either have an elongation at break of more than 300% but a reduced tensile strength that does not meet the usage requirements, or have tensile strength that meets the usage requirements but an elongation at break of less than 300%, which does not meet the requirement that the elongation at break can exceed 300% and the noise level should be less than 40 decibels.

[0036] For the above performance tests, the masterbatch density was tested according to Method A in standard GB / T 1033.1-2008 "Determination of density of non-foamed plastics - Part 1: Immersion method, liquid pyrometer method and titration method"; the yield strength and elongation at break of the pipe were tested according to standard GB / T 8804.3-2003 "Determination of tensile properties of thermoplastic pipes - Part 3: Polyolefin pipes"; and the drainage noise of the pipe was tested according to standard CJ / T 312-2009 "Test method for noise of building drainage pipe system".

[0037] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing HDPE silent masterbatch with improved toughness, characterized in that, Includes the following steps: a. Prepare the following raw materials by weight: 90-100 parts HDPE, 10-30 parts nano calcium carbonate, 25-40 parts barium sulfate, 1-2 parts stearic acid, and 8-10 parts titanium dioxide. b. After mixing all raw materials, extrude and granulate to obtain a density of 1.2–1.3 g / cm³. 3 High-toughness HDPE silent masterbatch.

2. The method for preparing a method to improve the toughness of HDPE silent masterbatch according to claim 1, characterized in that, In step b, all raw materials are mixed evenly using a mixer at a temperature of 40–60°C.

3. The method for preparing a method to improve the toughness of HDPE silent masterbatch according to claim 2, characterized in that, The mixer speed is 400-500 rpm, and the mixing time is 1.5-2 minutes.

4. The method for preparing a method to improve the toughness of HDPE silent masterbatch according to claim 1, characterized in that, In step b, a parallel twin-screw extruder is used for extrusion granulation. The extrusion granulation process conditions are: barrel temperature 180-190℃, die temperature 200-210℃, screw speed 400-450 rpm, feed speed 30-45 rpm, and cutting speed 500-600 rpm.

5. The method for preparing a method to improve the toughness of HDPE silent masterbatch according to claim 1, characterized in that, HDPE density is 0.94–0.96 g / cm³. 3 The melt index measured at 190℃ and 5kg load was 18-21g / 10min.

6. The method for preparing a method to improve the toughness of HDPE silent masterbatch according to claim 1, characterized in that, The barium sulfate particle size is 400-500 mesh.

7. The method for preparing a method to improve the toughness of HDPE silent masterbatch according to claim 1, characterized in that, The melt index of the HDPE silent masterbatch, measured at 190℃ and 5kg load, was 0.4~0.8g / 10min.

8. The method for preparing a method to improve the toughness of HDPE silent masterbatch according to claim 1, characterized in that, HDPE silent masterbatch is made from the following raw materials in parts by weight: 100 parts HDPE, 12-17 parts nano calcium carbonate, 25-35 parts barium sulfate, 1-2 parts stearic acid, and 8-10 parts titanium dioxide.

9. The method for preparing a method to improve the toughness of HDPE silent masterbatch according to claim 1, characterized in that, HDPE silent masterbatch is made from the following raw materials in parts by weight: 100 parts HDPE, 16.5 parts nano calcium carbonate, 27.6 parts barium sulfate, 2 parts stearic acid, and 8 parts titanium dioxide.