AU2020397281B2

AU2020397281B2 - Composite antistatic agent and preparation method therefor, antistatic polyoxymethylene and preparation method therefor

Info

Publication number: AU2020397281B2
Application number: AU2020397281A
Authority: AU
Inventors: Liang CHANG; Chuang He; Zhiyuan Li; Qiang Liu; Lanting LOU; Xiaoping Wu; Yaomeng XIAO; Kaifeng XU; Ziwen XUE; Lin Ye; Hua Zhang; Zhao Zhang; Xiaowen Zhao
Original assignee: Yankuang Lunan Chemicals Co Ltd
Current assignee: Yankuang Lunan Chemicals Co ltd
Priority date: 2019-12-04
Filing date: 2020-03-26
Publication date: 2022-12-22
Anticipated expiration: 2040-03-26
Also published as: CN111087791B; CN111087791A; AU2020397281A1; WO2021109368A1

Abstract

A composite antistatic agent. The preparation method therefor comprises: performing surface functionalization treatment on a metal oxide by using a coupling agent so as to obtain a modified metal oxide; performing melt mixing on polyethylene glycol, an alkaline earth metal compound and the modified metal oxide; and performing extrusion and granulation so as to obtain the composite antistatic agent. The metal oxide is ZnO, PbO, In

Description

COMPOSITE ANTISTATIC AGENT AND PREPARATION METHOD THEREOF, ANTISTATIC POLYOXYMETHYLENE AND PREPARATION METHOD THEREOF BACKGROUND

Technical Field

The present disclosure belongs to the field of processing of polymer materials, and relates to a composite antistatic agent and a preparation method thereof, antistatic polyoxymethylene and a preparation method thereof.

Related Art

Information of the Related Art part is merely disclosed to increase the understanding of the overall background of the present disclosure, but is not necessarily regarded as acknowledging or suggesting, in any form, that the information constitutes the prior art known to a person of ordinary skill in the art.

As a thermoplastic engineering plastic with [-CH 2-O-] as a main chain, no branching, high melting point, high density and high crystallization, polyoxymethylene (POM) has high strength, high stiffness, excellent creep resistance, fatigue resistance, inherent lubricity, wearing resistance, chemical resistance and the like, is a variety most similar to metal in engineering plastics, can be used to replace copper, aluminum, zinc, other non-ferrous metals and alloy products and is widely used in electronic and electrical, automobiles, light industry, machinery, chemicals, building materials and other fields.

In some cases, POM resin is required to have an antistatic property when used as a part in a recording media device or a part in a dusty working environment in order to prevent dust adhesion or various malfunctions caused by static electricity; especially since POM is most widely used as various power transmission and conduction components such as gears, pulleys, slides or slide rails due to excellent frictional wearing characteristic, various accidental damages can be caused to these parts due to electrostatic charge generated by friction, and POM is also required to have both good frictional wearing characteristic and good antistatic property, but POM is one of resins difficult to undergo antistatic treatment. This is because that the thermal stability of POM is low, and violent decomposition of POM during molding processing is likely to be caused by the use of small-molecule surfactant antistatic agents with high polarity; at the same time, since POM is low in polarity and high in crystallinity, the compatibility with antistatic agents is low. According to the Chinese invention patent ZL200780043435.2, conductive carbon black is used to prepare electrostatic dissipative POM, and the surface resistivity can reach 10' to 104 Q. It has been discovered by inventors of the present disclosure that the antistatic ability of the POM material needs to be improved, the mechanical toughness is greatly reduced, and a black product is obtained.

SUMMARY

In order to overcome the shortcomings in the prior art, an objective of the present disclosure is to provide a composite antistatic agent and a preparation method thereof, antistatic polyoxymethylene and a preparation method thereof. Polyoxymethylene prepared by using the composite antistatic agent has better antistatic performance and mechanical toughness.

To achieve the objective, the present disclosure includes the following technical solutions:

In an aspect, a method for preparing a composite antistatic agent is provided, which includes performing surface functionalization treatment on a metal oxide by using a coupling agent to obtain a modified metal oxide, and performing melt mixing and extrusion granulation on polyethylene glycol, an alkaline earth metal compound and the modified metal oxide to obtain the composite antistatic agent; and the metal oxide is ZnO, PbO, In202, SnO,V 20 2 ,CuO or TiO 2 .

In the present disclosure, polyethylene glycol (PEO) is compounded with the alkaline earth metal compound and the metal oxide to use as an antistatic agent, and based on a situation that a shared electron pair on an ether oxygen atom in a PEO polyelectrolyte molecular chain has a strong tendency to form a hydrogen bond, PEO can form an association complex with the alkaline earth metal compound to have ion conductivity; the metal oxide also has good electrical conductivity and can be combined with PEO and polyoxymethylene when modified with the coupling agent, so that PEO can be compounded with the alkaline earth metal compound and the metal oxide to obtain the antistatic agent.

In another aspect, a composite antistatic agent is provided, which is obtained by using the preparation method above.

In the antistatic agent of the present disclosure, PEO has good compatibility with polyoxymethylene. It is found through experiments that polyoxymethylene can be endowed with good antistatic performance and mechanical toughness by using the antistatic agent of the present disclosure.

In a third aspect, application of the composite antistatic agent above in preparation of antistatic polyoxymethylene is provided.

In a fourth aspect, antistatic polyoxymethylene is provided, which includes polyoxymethylene, an antioxidant, a formaldehyde absorbent and the composite antistatic agent above.

In a fifth aspect, a method for preparing antistatic polyoxymethylene includes performing melt mixing and extrusion granulation on polyoxymethylene, the antioxidant, the formaldehyde absorbent and the composite antistatic agent above to obtain the antistatic polyoxymethylene.

According to the composite antistatic polyoxymethylene prepared in the present disclosure, a surface resistivity can reach 1011 to 1014 Q, high mechanical performance is maintained, the notch impact strength can reach about 7-15 KJ/m 2 , the tensile strength can reach 40-60 MPa, and the elongation at break can reach 40-90%.

Beneficial effects of the present disclosure are as follows:

(1) In the present disclosure, PEO and polyoxymethylene have similar molecular structures and good compatibility; the molecular weight is relatively high, and migration losses during use are not likely to be caused, so that the durability of antistatic performance of polyoxymethylene is maintained.

(2) In the present disclosure, the shared electron pair on the ether oxygen atom in the PEO polyelectrolyte molecular chain has the strong tendency to form the hydrogen bond, and an alkaline earth metal compound ion can undergo coordination with the shared electron pair to form the association complex; and a conductive path is formed during migration of the polyelectrolyte in a polymer.

(3) In the present disclosure, the metal oxide also has good electrical conductivity, and the interface compatibility with a polyoxymethylene matrix can be improved after the metal oxide is subjected to surface treatment with the coupling agent.

(4) In the present disclosure, since PEO has good compatibility with polyoxymethylene molecules, PEO is compounded with the alkaline earth metal compound/metal oxide to prepare the composite antistatic agent first, so that the alkaline earth metal compound/metal oxide is more uniformly dispersed in the polyoxymethylene matrix, and polyoxymethylene is endowed with good antistatic performance and mechanical performance.

DETAILED DESCRIPTION

It should be noted that, the following detailed descriptions are all exemplary, and are intended to provide further descriptions of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present disclosure belongs.

It should be noted that terms used herein are only for describing specific implementations and are not intended to limit exemplary implementations according to the present disclosure. As used herein, the singular form is also intended to include the plural form unless the context clearly dictates otherwise. In addition, it should further be understood that, terms "include" and/or "include" used in this specification indicate that there are features, steps, operations, devices, components, and/or combinations thereof.

Since the thermal stability of POM is low, violent decomposition of POM during molding processing is likely to be caused by the use of small-molecule surfactant antistatic agents with high polarity; at the same time, since POM is low in polarity and high in crystallinity, the compatibility with antistatic agents is low, and POM is one of resins difficult to undergo antistatic treatment. The present disclosure provides a composite antistatic agent and a preparation method thereof, antistatic polyoxymethylene and a preparation method thereof.

In a typical embodiment of the present disclosure, a method for preparing a composite antistatic agent is provided and includes performing surface functionalization treatment on a metal oxide by using a coupling agent to obtain a modified metal oxide, and performing melt mixing and extrusion granulation on polyethylene glycol, an alkaline earth metal compound and the modified metal oxide to obtain the composite antistatic agent; and the metal oxide is ZnO, PbO, In202, SnO, V 2 0 2 , CuO or TiO 2

. In the present disclosure, PEO is compounded with the alkaline earth metal compound and the metal oxide to use as an antistatic agent, and based on a situation that a shared electron pair on an ether oxygen atom in a PEO polyelectrolyte molecular chain has a strong tendency to form a hydrogen bond, PEO can form an association complex with the alkaline earth metal compound to have ion conductivity; the metal oxide also has good electrical conductivity and can be combined with PEO and polyoxymethylene when modified with the coupling agent, so that PEO can be compounded with the alkaline earth metal compound and the metal oxide to obtain the antistatic agent.

In one or more examples of the embodiment, the step of surface functionalization treatment includes: dispersing the coupling agent and the metal oxide in a solvent and performing ultrasonic treatment at a temperature not lower than 45°C (ultrasonic treatment frequency is 20 KHz to 120 KHz).

In this series of examples, the solvent is a mixture of water and ethanol. When a volume ratio of water to ethanol is 1:8.5-9.5, the dispersion effect of the coupling agent and the metal oxide is better.

In this series of examples, an ultrasonic treatment time is 0.5-2 hours.

In one or more examples of the embodiment, a rotation speed of a screw rod for melt mixing and extrusion granulation is 50-100 r/min, and a temperature of a charging barrel is 100-180 0 C.

In one or more examples of the embodiment, a mass ratio of the coupling agent to the metal oxide is 0.005-1:0.05-20.

In one or more examples of the embodiment, amass ratio of the coupling agent to the metal oxide to polyethylene glycol to the alkaline earth metal compound is 0.005-1:0.05-20:0.5-20:0.05-10.

In one or more examples of the embodiment, the coupling agent is a silane coupling agent, a titanate coupling agent, an aluminate coupling agent or a phosphate coupling agent.

In one or more examples of the embodiment, a molecular weight of polyethylene glycol is 1x10 3 to 5x10 6 .

In one or more examples of the embodiment, the alkaline earth metal compound is magnesium oxide, calcium oxide, calcium silicate, calcium glycerophosphate, calcium carbonate or calcium stearate.

In another embodiment of the present disclosure, a composite antistatic agent is provided, which is obtained by using the preparation method above.

In a third embodiment of the present disclosure, application of the composite antistatic agent above in preparation of antistatic polyoxymethylene is provided.

In a fourth embodiment of the present disclosure, antistatic polyoxymethylene is provided, which includes polyoxymethylene, an antioxidant, a formaldehyde absorbent and the composite antistatic agent above.

In one or more examples of the embodiment, a mass ratio of polyoxymethylene to the antioxidant to the formaldehyde absorbent to a coupling agent to a metal oxide to polyethylene glycol to an alkaline earth metal compound is 100:0.05-5:0.05-5:0.005-1:0.05-20:0.5-20:0.05-10.

In one or more examples of the embodiment, the antioxidant is tetra[ P -(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester (namely Irganox 1010), N,N'-bis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hexanediamine (namely Irganox 1098), p-(4-hydroxy-3,5-di-tert-butylphenyl)octadecyl propionate (namely Irganox 1076) or 2,6-di-tert-butyl-4-methylphenol (namely BHT (264)).

In one or more examples of the embodiment, the formaldehyde absorbent is melamine, dicyandiamide, urea or hydrazide.

In a fifth embodiment of the present disclosure, a preparation method of antistatic polyoxymethylene is provided and includes performing melt mixing and extrusion granulation on polyoxymethylene, an antioxidant, a formaldehyde absorbent and the composite antistatic agent above to obtain the antistatic polyoxymethylene.

In one or more examples of the embodiment, a rotation speed of a screw rod is 50-200 r/min, and a temperature of a charging barrel is 140-220°C.

In order to enable a person skilled in the art to understand the technical solutions of the present disclosure more clearly, the technical solutions of the present disclosure will be described in detail below with reference to specific embodiments and comparative examples.

In the following examples, a method for surface treatment of the metal oxide includes:

dispersing 25 g of a silane coupling agent and 500 g of the metal oxide in a water-ethanol solution (volume ratio is 1:9) with a concentration of 5%, performing ultrasonic treatment (ultrasonic treatment power is 200 W, and frequency is 80 KHz) at 50°C for 1 hour, and then performing suction filtration and drying to obtain a surface-treated metal oxide.

Example 1: Preparation of composite antistatic polyoxymethylene

1 kg of polyethylene glycol (molecular weight 5000), 500 g of MgO and 500 g of surface-treated ZnO were added into a high-speed mixer for mixing and then subjected to melt mixing and extrusion granulation by using a vented twin-screw extruder to obtain a composite antistatic agent, where a rotation speed of a screw rod was 50 r/min, and a temperature of a charging barrel was 100-120°C.

10 kg of POM resin (melting index 9-27 g/Omin), 30 g of tetra[ P -(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, 20 g of melamine and 1.6 kg of the prepared composite antistatic agent were added into the high-speed mixer for mixing and then subjected to melt mixing and extrusion granulation by using the vented twin-screw extruder to obtain reinforced and toughened polyoxymethylene, where the rotation speed of the screw rod was 50 r/min, and the temperature of the charging barrel in each stage was 140-200°C. A surface resistivity of the product can reach 1012 Q, the notch impact strength can reach about 12 KJ/m2 , the tensile strength can reach 50 MPa, and the elongation at break can reach 70%.

Example 2: Preparation of composite antistatic polyoxymethylene

700 g of polyethylene glycol (molecular weight 3x10 6), 100 g of calcium silicate and 200 g of surface-treated SnO were added into a high-speed mixer for mixing and then subjected to melt mixing and extrusion granulation by using a vented twin-screw extruder to obtain a composite antistatic agent, where a rotation speed of a screw rod was 70 r/min, and a temperature of a charging barrel was 120-140°C.

10 kg of POM resin (melting index 9-27 g/10min), 40 g of N,N'-bis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hexanediamine, 10 g of dicyandiamide and 1.1 kg of the prepared composite antistatic agent were added into the high-speed mixer for mixing and then subjected to melt mixing and extrusion granulation by using the vented twin-screw extruder to obtain reinforced and toughened polyoxymethylene, where the rotation speed of the screw rod was 150 r/min, and the temperature of the charging barrel in each stage was 160-220°C. A surface resistivity of the product can reach 1012 Q, the notch impact strength can reach about 10 KJ/m2 , the tensile strength can reach 52 MPa, and the elongation at break can reach 60%.

Example 3: Preparation of composite antistatic polyoxymethylene

1.5 kg of polyethylene glycol (molecular weight 2x10 5), 300 g of calcium stearate and 1.5 kg of surface-treated TiO2 were added into a high-speed mixer for mixing and then subjected to melt mixing and extrusion granulation by using a vented twin-screw extruder to obtain a composite antistatic agent, where a rotation speed of a screw rod was 90 r/min, and a temperature of a charging barrel was 150-180°C.

10 kg of POM resin (melting index 9-27 g/10min), 10 g of P -(4-hydroxy-3,5-di-tert-butylphenyl)octadecy propionate, 70 g of urea and 3.3 kg of the prepared composite antistatic agent were added into the high-speed mixer for mixing and then subjected to melt mixing and extrusion granulation by using the vented twin-screw extruder to obtain reinforced and toughened polyoxymethylene, where the rotation speed of the screw rod was 100 r/min, and the temperature of the charging barrel in each stage was 170-210°C. A surface resistivity of the product can reach 1011 Q, the notch impact strength can reach about 10 KJ/m2 , the tensile strength can reach 40 MPa, and the elongation at break can reach 50%.

The foregoing descriptions are merely preferable embodiments of the present disclosure, but are not intended to limit the present disclosure. The present disclosure may include various modifications and changes for a person skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present disclosure shall fall within the protection scope of the present disclosure.

Claims

CLAIMS What is Claimed is:

1. A method for preparing a composite antistatic polyoxymethylene, including the step of surface functionalization treatment on a metal oxide by using a coupling agent to obtain a modified metal oxide, and performing melt mixing and extrusion granulation on polyethylene glycol, an alkaline earth metal compound and the modified metal oxide, wherein the metal oxide is ZnO, PbO, In202, SnO, V 2 0 2 , CuO or TiO 2 and wherein a molecular weight of polyethylene glycol islx1O 3 to 5x106 ;

the step of surface functionalization treatment includes dispersing the coupling agent and the metal oxide in a solvent and performing ultrasonic treatment at a temperature not lower than °C, wherein mass ratio of the coupling agent to the metal oxide is 0.005-1:0.05-20, or a mass ratio of the coupling agent to the metal oxide to polyethylene glycol to the alkaline earth metal compound is 0.005-1:0.05-20:0.5-20:0.05-10, wherein the alkaline earth metal compound is magnesium oxide, calcium oxide, calcium silicate, calcium glycerophosphate, calcium carbonate or calcium stearate; and

wherein the prepared composite antistatic polyoxymethylene further includes an antioxidant, and a formaldehyde absorbent.

2. The method for preparing a composite antistatic polyoxymethylene of claim 1 wherein the solvent is a mixture of water and ethanol.

3. The method for preparing a composite antistatic polyoxymethylene of claim 2 wherein a volume ratio of water to ethanol is 1:8.5-9.5.

4. The method for preparing a composite antistatic polyoxymethylene according to anyone of claims 1 to 3 wherein ultrasonic treatment time is 0.5-2 hours.

5. The method for preparing a composite antistatic polyoxymethylene according to anyone of claims 1 to 4 wherein the coupling agent is a silane coupling agent, a titanate coupling agent, an aluminate coupling agent or a phosphate coupling agent.

6. The method for preparing a composite antistatic polyoxymethylene of anyone of claims 1 to 5 wherein a rotation speed of a screw rod for melt mixing and extrusion granulation is 50-100 r/min, and a temperature of a charging barrel is 100-180°C.

7. A composite antistatic polyoxymethylene, obtained by using the preparation method according to any one of claims 1 to 6.