阅读说明：本技术 一种改性pom材料及其制备方法 (Modified POM material and preparation method thereof ) 是由 邵军 赵金灿 于 2020-06-11 设计创作，主要内容包括：本发明公开了一种改性POM材料及其制备方法,按质量百分计,其制备原料包括以下组分：55～70％的POM树脂、8～20％的AES树脂、6～15％的聚苯乙烯、4～10％的改性纳米碳化硅晶须、2～4％的植物蜡、1～5％POE接枝马来酸酐共聚物、2～4％丙烯腈-苯乙烯接枝马来酸酐共聚物、0.5～2％的抗氧剂。本发明配方设计合理,制备工艺易行,配方设计合理,制备工艺易行,所得改性POM材料尤其是具有成型收缩率小、耐老化、热稳定性好等优点,采用该改性材料注塑成包装材料可有效解决传统方式使用润滑油所存在的膏体污染问题。(The invention discloses a modified POM material and a preparation method thereof, wherein the preparation raw materials comprise the following components in percentage by mass: 55-70% of POM resin, 8-20% of AES resin, 6-15% of polystyrene, 4-10% of modified nano silicon carbide whisker, 2-4% of vegetable wax, 1-5% of POE grafted maleic anhydride copolymer, 2-4% of acrylonitrile-styrene grafted maleic anhydride copolymer and 0.5-2% of antioxidant. The invention has reasonable formula design, easy preparation process, reasonable formula design and easy preparation process, the obtained modified POM material especially has the advantages of small molding shrinkage, aging resistance, good thermal stability and the like, and the problem of paste pollution caused by using lubricating oil in the traditional mode can be effectively solved by adopting the modified material to injection mold the packaging material.)

1. A modified POM material characterized by: the preparation raw materials comprise the following components in percentage by mass: 55-70% of POM resin, 8-20% of AES resin, 6-15% of polystyrene, 4-10% of modified nano silicon carbide whisker, 2-4% of vegetable wax, 1-5% of POE grafted maleic anhydride copolymer, 2-4% of acrylonitrile-styrene grafted maleic anhydride copolymer and 0.5-2% of antioxidant.

2. The modified POM material of claim 1, wherein: the antioxidant is one or more of antioxidant 1010, antioxidant 1076 and antioxidant 168.

3. A method for preparing the modified POM material as claimed in any one of claims 1 to 2, wherein the method comprises the following steps: the method comprises the following steps:

(1) respectively preparing a CMC aqueous solution, a PAAS aqueous solution and a SHMP aqueous solution with the concentration of 0.15%, sequentially adding the CMC aqueous solution and the PAAS aqueous solution into the SHMP aqueous solution under the ultrasonic environment of 30 ℃, mixing for 1h, and adjusting the pH to 10 by using NaOH to obtain a mixed dispersion liquid, wherein the mass ratio of the CMC, the PAAS and the SHMP in the mixed dispersion liquid is 3: 1.2: 4;

(2) preparing a nano silicon carbide whisker water suspension with the concentration of 50%, adding the nano silicon carbide whisker water suspension into the mixed dispersion liquid, mixing for 30min under the conditions of ultrasonic and mechanical stirring, and performing suction filtration, washing and drying to obtain modified nano silicon carbide whiskers, wherein the mass ratio of the nano silicon carbide whisker water suspension to the mixed dispersion liquid is 1: 1.4;

(3) the POM resin is dried for 4 hours in vacuum at 85 ℃, and then the dried POM resin, the modified nano silicon carbide whisker, the polystyrene and the POE grafted maleic anhydride copolymer are uniformly mixed and then added into a double-screw extruder for melt blending to obtain a first molten material;

(4) and uniformly mixing the AES resin, the acrylonitrile-styrene grafted maleic anhydride copolymer, the vegetable wax and the antioxidant, adding the mixture into the first molten material, carrying out melt blending by using a double-screw extruder to obtain a second molten material, and carrying out extrusion granulation to obtain the modified POM material.

4. The process for preparing a modified POM material according to claim 3, wherein: in the step (4), the extrusion temperature of the first zone to the fifth zone of the double-screw extruder is 210 ℃, 200 ℃, 195 ℃, 190 ℃ and 180 ℃ in sequence.

Technical Field

The invention relates to the technical field of macromolecules, in particular to a modified POM material and a preparation method thereof.

Background

Polyoxymethylene is widely used and manufactured in spiral tubes for lipstick type packaging bottles because it has high modulus of elasticity, rigidity and surface hardness, and has good wear resistance and self-lubricity. In the prior art, lubricating oil is needed to be used among the spiral tube, the fork and the beads of a lipstick packaging bottle to realize smooth and flexible rotation among parts, but the lubricating oil is odorous and easily pollutes the cream body, and meanwhile, after the lipstick packaging bottle is used for a long time, the lubricating oil is easy to lose efficacy, so that unsmooth operation among the spiral tube, the fork and the beads is caused. In addition, because the polyformaldehyde has the defects of large shrinkage, poor thermal stability and easy decomposition and aging, the common polyformaldehyde material cannot meet the high requirements of people on cosmetic packaging, and needs to be improved.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a modified POM material and a preparation method thereof, the formula design is reasonable, the preparation process is easy to implement, the obtained modified POM material especially has the advantages of small molding shrinkage, aging resistance, good thermal stability and the like, and the problem of paste pollution caused by using lubricating oil in the traditional mode can be effectively solved by adopting the modified material to prepare the packaging material by injection molding.

In order to achieve the purpose, the invention adopts the following technical scheme:

the modified POM material comprises the following raw materials in percentage by mass: 55-70% of POM resin, 8-20% of AES resin, 6-15% of polystyrene, 4-10% of modified nano silicon carbide whisker, 2-4% of vegetable wax, 1-5% of POE grafted maleic anhydride copolymer, 2-4% of acrylonitrile-styrene grafted maleic anhydride copolymer and 0.5-2% of antioxidant.

The antioxidant is one or more of antioxidant 1010, antioxidant 1076 and antioxidant 168.

A preparation method of a modified POM material comprises the following steps:

(1) respectively preparing a CMC aqueous solution, a PAAS aqueous solution and a SHMP aqueous solution with the concentration of 0.15%, sequentially adding the CMC aqueous solution and the PAAS aqueous solution into the SHMP aqueous solution under the ultrasonic environment of 30 ℃, mixing for 1h, and adjusting the pH to 10 by using NaOH to obtain a mixed dispersion liquid, wherein the mass ratio of the CMC, the PAAS and the SHMP in the mixed dispersion liquid is 3: 1.2: 4;

the nanometer silicon carbide whiskers are in an energy unstable state due to small particle size, large surface atom proportion, large specific surface area, lack of adjacent coordination atoms on the surface, and surface energy beating, and are easy to coagulate and agglomerate in the preparation and transportation processes to form secondary particles, so that modification is needed. Because CMC and PAAS have their own or cross-linked structure each other, this entangle and produce the resistance to the flow of the solid particle easily, moreover when CMC is insufficient, PAAS is used excessively, the long chain of CMC will twine each other, form the firm stereoscopic network structure, this kind of structure forms the steric hindrance effect to the solid particle, can prevent the silicon carbide whisker of nanometer from sinking, but this kind of structure will make the flow property of the silicon carbide whisker suspension of nanometer reduce greatly, is unfavorable for the dispersion of the silicon carbide whisker of nanometer, therefore must carry on the strict proportion to the mixed dispersion liquid, can utilize certain interaction that exists among the three to prevent the granule in the mixed dispersion liquid from reuniting, keep the suspension of the granule, reduce and subside. In addition, the PAAS aqueous solution has high viscosity, so that the PAAS aqueous solution, the CMC aqueous solution and the SHMP aqueous solution are required to be prepared respectively and then mixed, in addition, the PAAS aqueous solution and the CMC aqueous solution have a synergistic interaction effect, so that the viscosity of the mixed dispersion liquid can be increased, the fluidity can be reduced, and the viscosity of the PAAS aqueous solution is greater than that of the CMC aqueous solution, so that the PAAS aqueous solution and the CMC aqueous solution are sequentially added into the SHMP aqueous solution to ensure the compatibility of the mixed dispersion liquid, and further ensure the uniform dispersion of the nano silicon carbide whiskers.

(2) Preparing a nano silicon carbide whisker water suspension with the concentration of 50%, adding the nano silicon carbide whisker water suspension into the mixed dispersion liquid, mixing for 30min under the conditions of ultrasonic and mechanical stirring, and performing suction filtration, washing and drying to obtain modified nano silicon carbide whiskers, wherein the mass ratio of the nano silicon carbide whisker water suspension to the mixed dispersion liquid is 1: 1.4;

(3) the POM resin is dried for 4 hours in vacuum at 85 ℃, and then the dried POM resin, the modified nano silicon carbide whisker, the polystyrene and the POE grafted maleic anhydride copolymer are uniformly mixed and then added into a double-screw extruder for melt blending to obtain a first molten material;

the molding shrinkage of polyformaldehyde is 1.9-2.3%, the most important characteristics of polystyrene are thermal stability, fluidity and easy molding processability during melting, and the molding shrinkage is 0.3-0.6%, so that polystyrene has an obvious effect on improving the molding shrinkage of polyformaldehyde. Due to the high crystallinity of polyformaldehyde, the quantity of crystal nuclei formed by polyformaldehyde is small during processing and molding, so that the size of crystallized spherulites is large, the interpenetration of molecular chains on the spherulite interface is small, and the notch impact strength and toughness of the product are reduced. In the step, the modified nano silicon carbide whiskers are added and used as a nucleating agent, so that the crystallization property and the form of polyformaldehyde are improved, the size of spherulites is reduced, and the mechanical property of polyformaldehyde is improved. However, if the crystallinity of polyoxymethylene is increased, the polyoxymethylene will undergo a large volume change during molding and processing, and the molding shrinkage will also increase with the crystallinity, so that polystyrene is blended with POM resin and modified nano silicon carbide whiskers simultaneously, and the addition of polystyrene can blend part of the modified nano silicon carbide whiskers into polystyrene, reduce the dispersion of the modified nano silicon carbide whiskers in the POM resin, improve the crystallinity, and improve the processing fluidity of the first melt, thereby improving the molding shrinkage and thermal stability of the product.

The POE grafted maleic anhydride copolymer is used as a compatibilizer, so that the compatibility of polystyrene and POM resin is improved, the modified nano silicon carbide crystal is further promoted to be uniformly dispersed in the polystyrene and the POM resin, and the POM resin is prevented from being excessively crystallized.

(4) And uniformly mixing the AES resin, the acrylonitrile-styrene grafted maleic anhydride copolymer, the vegetable wax and the antioxidant, adding the mixture into the first molten material, carrying out melt blending by using a double-screw extruder to obtain a second molten material, and carrying out extrusion granulation to obtain the modified POM material.

In the step (4), the extrusion temperature of the first zone to the fifth zone of the double-screw extruder is 210 ℃, 200 ℃, 195 ℃, 190 ℃ and 180 ℃ in sequence.

The AES resin has excellent impact resistance, low-temperature usability, aging resistance, oil resistance and thermal stability, and the temperature of AES with 50% of polymer weight loss is 420 ℃, which is basically the same as ABS resin, the aging resistance is 4-8 times of ABS resin, and the aging resistance and the thermal stability of ABS resin are obviously superior to POM, so that the AES resin with reasonable proportion can effectively improve the aging resistance and the thermal stability of POM.

The vegetable wax is a natural plastic auxiliary agent, the vegetable wax is directly added into the formula, so that the modified POM material has better lubricity, after the modified POM material is injected into a spiral tube, the spiral tube and other parts of the lipstick packaging tube can smoothly and flexibly rotate without using lubricating oil, the problem of paste pollution caused by using the lubricating oil is solved, and the using effect of the packaging tube can be kept for a long time.

The acrylonitrile-styrene grafted maleic anhydride copolymer is used as a solubilizer to reduce the interfacial tension between the AES resin and the polystyrene and POM resin and improve the compatibility of the AES resin, the polystyrene and the POM resin, and can be used as a substitute of common SAN to improve the heat resistance and the impact resistance of the mixture.

The invention has the beneficial effects that:

(1) during the preparation process of the modified nano silicon carbide whisker, PAAS, CMC and SHMP are used as a compound dispersant, and the PAAS, CMC and SHMP have the best synergistic interaction and the viscosity of a mixed dispersion liquid through the control of different addition sequences and proportions, so that the uniform dispersibility of the nano silicon carbide whisker is ensured.

(2) The POM resin, the modified nano silicon carbide whiskers and the polystyrene are subjected to first-step melting mixing so as to further adjust the dispersion uniformity of the modified nano silicon carbide whiskers, control over the crystallinity of the POM resin is facilitated, the molding shrinkage rate is improved, and the POM resin, the polystyrene and the POM resin are subjected to blending operation, so that the melt flowability can be further improved, and the processability is improved.

(3) The modified POM material prepared by the formula and the preparation method has the advantages of wear resistance, self lubrication, impact resistance and the like, overcomes the defects of common POM in the aspects of aging resistance, thermal stability and molding shrinkage, can be used for injection molding to produce packaging materials with better comprehensive properties, and meets the high requirements of people on the packaging materials.

(4) By adding the vegetable wax, the lubricity of the POM material is improved, the problem of paste pollution caused by the traditional use of lubricating oil is solved, the problem of reduction of the rotation smoothness caused by the volatilization of the lubricating oil is avoided, and the cosmetic packaging product can keep the use effect for a long time.

Detailed Description

The invention is further described below with reference to specific embodiments: