A kind of polypropylene material and its preparation method and application

Abstract

The present invention discloses a polypropylene material and a preparation method and application thereof. The polypropylene material comprises the following components: 98-100 parts of homopolymer polypropylene resin; 0.2-1 parts of aryl phosphate salt nucleating agent; 0.2-1 parts of lubricant; 0.01-0.04 parts of peroxide initiator; the lubricant is selected from any one or more of silicone lubricants or erucamide lubricants. The present invention prepares a high-fluidity polypropylene material by adding a specific nucleating agent, lubricant and peroxide initiator to the polypropylene resin, which can meet multi-cavity high-speed injection molding and can maintain good concentricity of the molded product.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a polypropylene material and a preparation method and application thereof. Background Art

[0002] Polypropylene is one of the most widely used general-purpose plastics today. Due to its high chemical resistance, good biocompatibility, light weight and low price, it is widely used in medical consumables. The demand for medical testing consumables is rising rapidly. At the same time, for high-throughput, high-efficiency and rapid testing, the reliability, stability and cost requirements of testing equipment and consumables are getting higher and higher. For example, pipette tips: As consumables used in conjunction with pipettes, the number of pipette tips used in medical testing experiments is very large. Pipette tips have the characteristics of deep cavities and thin walls, and require multi-hole high-speed injection molding production (while increasing production, it also ensures the processing accuracy of the product). However, polypropylene materials have low fluidity, large shrinkage and easy deformation after molding, which cannot meet the requirements of multi-hole high-speed injection molding. In addition, the concentricity of the molded product pipette tips is poor, which will affect the accuracy of pipetting and cause errors in pipetting, making it difficult to meet the accuracy requirements of medical testing. This problem has limited the application of polypropylene materials in modern medical consumables. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the present invention aims to provide a high-fluidity polypropylene material that can meet the requirements of multi-cavity high-speed injection molding and can maintain good concentricity of the molded product.

[0004] The present invention is achieved through the following technical solutions:

[0005] A polypropylene material, comprising the following components by weight:

[0006] Polypropylene resin 98-100 parts;

[0007] 0.2-1 part of aryl phosphate nucleating agent;

[0008] Lubricant 0.2-1 part;

[0009] Peroxide initiator 0.01-0.04 parts;

[0010] The lubricant is selected from any one or more of silicone lubricants or erucamide lubricants.

[0011] Preferably, the aryl phosphate nucleating agent is selected from any one or more of bis[2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate]hydroxyaluminum salt or 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt; more preferably, the aryl phosphate nucleating agent is selected from bis[2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate]hydroxyaluminum salt.

[0012] Preferably, the lubricant is a silicone lubricant and an erucamide lubricant compounded in a weight ratio of (0.2-5):1; more preferably, the lubricant is a silicone lubricant and an erucamide lubricant compounded in a weight ratio of (0.5-2):1.

[0013] Preferably, the peroxide initiator is selected from any one or more of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,3-dimethyl-2,3-diphenylbutane or azobisisobutylcyanide, and more preferably, the peroxide initiator is selected from 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0014] Preferably, the homopolymer polypropylene resin has a melt index of 40-60 g / 10 min at 230° C. and 2.16 kg, more preferably 50-55 g / 10 min.

[0015] The present invention also provides a method for preparing the above-mentioned polypropylene material, comprising the following steps: uniformly mixing the components according to a ratio, then adding the mixture into a main feeding system of a twin-screw extruder, and preparing the polypropylene material through melt blending and extrusion granulation by the twin-screw extruder; wherein the temperature of the twin-screw extruder is set to 120°C-230°C, and the screw speed is 300rpm-600rpm.

[0016] The present invention also provides the use of the polypropylene material in the preparation of medical testing consumables, which can be used to prepare liquid transfer tips, pipettes, etc.

[0017] The present invention has the following beneficial effects:

[0018] The invention adds a specific lubricant, an aromatic phosphate salt nucleating agent and a peroxide initiator to a polypropylene resin. On the one hand, the peroxide initiator and the lubricant work together to effectively improve the fluidity of the material, and at the same time, the peroxide initiator decomposes small molecules to work together with the nucleating agent to improve the crystallization speed of the material, thereby effectively reducing the injection molding time. On the other hand, the addition of the nucleating agent effectively improves the modulus and stiffness of the material, reduces the stress formed during the molding process, and the lubricant further reduces the demoulding force of the material. Thus, a high-fluidity polypropylene material is prepared, which can meet the requirements of multi-cavity high-speed injection molding and can maintain the concentricity of the molded product (the melt index is 54-85 g / 10min under the conditions of 230° C. and 2.16 kg, the injection time of a 1000ul pipette for 32-cavity injection molding is ≤10s, and the concentricity of a 1000ul pipette for 32-cavity injection molding is ≤0.6mm). Implementation

[0019] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0020] The raw materials used in the embodiments and comparative examples of the present invention are described as follows, but are not limited to these materials:

[0021] Homopolymer polypropylene resin 1: Sinopec PP 450, melt index at 230°C, 2.16kg is 55 g / 10min;

[0022] Homopolymer polypropylene resin 2: Sinopec PP H9018, melt index at 230°C, 2.16kg is 60 g / 10min;

[0023] Copolymer polypropylene resin: PP BX3900, SK Chemical, melt index at 230°C, 2.16kg is 50g / 10min;

[0024] Nucleating agent 1: aryl phosphate nucleating agent, bis[2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate] hydroxyaluminum salt, TMP-6, Shanxi Chemical Research Institute;

[0025] Nucleating agent 2: aryl phosphate nucleating agent, NAP-62, Chenghe Technology;

[0026] Nucleating agent 3: sorbitol nucleating agent, brand 3988, Milliken;

[0027] Nucleating agent 4: organic metal salt nucleating agent, NAB-82, Chenghe Technology;

[0028] Lubricant 1: Silicone lubricant, GR-C0590P, Zhejiang Ge Rui;

[0029] Lubricant 2: erucamide, Xipu Chemical;

[0030] Lubricant 3: EBS lubricant, EBS B50, Guangzhou Runfeng;

[0031] Peroxide initiator 1: 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, LQ-DTBP, Lanzhou Additive Factory;

[0032] Peroxide initiator 2: benzoyl peroxide, ENOX BPO, Jiangsu Qiangsheng;

[0033] Peroxide initiator 3: diisopropylbenzene peroxide, Xiangyun, Anhui.

[0034] Preparation methods of polypropylene composite materials of embodiments and comparative examples:

[0035] According to the ratio of Table 1 / Table 2, the components were mixed evenly, and then the mixture was added to the main feeding system of the twin-screw extruder, and the polypropylene material was prepared by melt blending and extrusion granulation through the twin-screw extruder; wherein the temperature of the first to second zones of the twin-screw extruder was 120°C-160°C, the temperature of the third to fifth zones was 180°C-200°C, the temperature of the fifth to tenth zones was 200°C-230°C, and the screw speed was 500rpm.

[0036] Related performance test methods:

[0037] (1) Melt index: Tested according to ISO1133-1:2011 standard, test conditions are 230℃, 2.16kg.

[0038] (2) Multi-hole high-speed injection molding test: 1000ul pipette tips were injected into 32 holes, the injection time was recorded (the minimum injection cycle under the same injection molding process), and the concentricity of the pipette tips was tested (i.e., the deviation between the center of the small end and the center of the large end of the pipette tip. The smaller the value, the better the concentricity). The concentricity can be measured using a two-dimensional measuring instrument. The specific test method is as follows: Since the pipette tip is conical, fix its large end and place a magnifying glass directly at the large end to measure the deviation between the center of the large end and the center of the small end.

[0039] Table 1: Distribution ratios of each group in Examples 1-13 (by weight) and related performance test results

[0040]

[0041] Comparing Examples 1 / 2 / 3 / 4 / 5, the lubricant is preferably a silicone lubricant and an erucamide lubricant compounded in a weight ratio of (0.5-2):1, which can meet the requirements of multi-cavity high-speed injection molding while maintaining good concentricity of the molded product.

[0042] Continued from Table 1:

[0043]

[0044] Table 2: Distribution ratios of each group of comparative examples 1-11 (by weight) and related performance test results

[0045]

[0046] Continued from Table 2:

[0047]

[0048] In comparative example 1 / 2, sorbitol nucleating agent or organic metal salt nucleating agent is used, the injection molding cycle is long and the concentricity of the molded product is poor.

[0049] In comparative example 3, excessive nucleating agent was added, the material fluidity was poor, and the injection molding cycle was long.

[0050] In Comparative Example 4, no nucleating agent was added, the injection molding cycle was long and the concentricity of the molded product was poor.

[0051] In comparative example 5, no lubricant is added, the material fluidity is poor, the injection molding cycle is long, it cannot meet the requirements of multi-cavity high-speed injection molding, and the concentricity of the molded product is poor.

[0052] In comparative examples 6 / 7 / 8, the use of EBS lubricants cannot effectively improve the injection molding performance of the materials, and the concentricity of the molded products is poor.

[0053] In Comparative Example 9, excessive addition of peroxide initiator resulted in excessive material fluidity, which in turn led to a significant decrease in material performance and poor concentricity of the molded product.

[0054] In Comparative Example 10, no peroxide initiator was added, the injection molding cycle was long and the concentricity of the molded product was poor.

[0055] In Comparative Example 11, copolymerized polypropylene resin was used. Due to cross-linking, the fluidity was significantly reduced, the injection molding cycle was long, and the concentricity of the molded product was very poor.

Claims

1. A polypropylene material, characterized in that: By weight, it includes the following components: Homopolymer polypropylene resin 98-100 parts; 0.2-1 part of aryl phosphate nucleating agent; Lubricant 0.2-1 part; Peroxide initiator 0.01-0.04 parts; The lubricant is selected from any one or more of silicone lubricants or erucamide lubricants.

2. The polypropylene material according to claim 1, characterized in that: The aromatic phosphate salt nucleating agent is selected from any one or more of bis[2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate] hydroxyaluminum salt or 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt.

3. The polypropylene material according to claim 1, characterized in that: The aromatic phosphate salt nucleating agent is selected from bis[2,2'-methylene-bis(4,6-di-tert-butylphenyl)phosphate]hydroxyaluminum salt.

4. The polypropylene material according to claim 1, characterized in that: The lubricant is a compound of a silicone lubricant and an erucamide lubricant in a weight ratio of (0.2-5):

1.

5. The polypropylene material according to claim 1, characterized in that: The lubricant is a compound of a silicone lubricant and an erucamide lubricant in a weight ratio of (0.5-2):

1.

6. The polypropylene material according to claim 1, characterized in that: The peroxide initiator is selected from any one or more of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, benzoyl peroxide or diisopropylbenzene peroxide.

7. The polypropylene material according to claim 1, characterized in that: The peroxide initiator is selected from 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

8. The polypropylene material according to claim 1, characterized in that: The homopolymer polypropylene resin has a melt index of 40-60 g / 10 min at 230° C. and 2.16 kg.

9. The polypropylene material according to claim 8, characterized in that: The homopolymer polypropylene resin has a melt index of 50-55 g / 10 min at 230° C. and 2.16 kg.

10. The method for preparing a polypropylene material according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: uniformly mixing the components according to a proportion, then adding the mixture into a main feeding system of a twin-screw extruder, and preparing a polypropylene material through melt blending and extrusion granulation by the twin-screw extruder; wherein the temperature of the twin-screw extruder is set at 120°C-230°C, and the screw speed is 300rpm-600rpm.

11. Use of the polypropylene material according to any one of claims 1 to 9 in the preparation of medical testing consumables.

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