阅读说明：本技术 一种疏水自洁聚氯乙烯薄膜及制备方法 (Hydrophobic self-cleaning polyvinyl chloride film and preparation method thereof ) 是由 徐卫根 于 2020-07-09 设计创作，主要内容包括：本发明属于功能塑料薄膜领域,具体涉及一种疏水自洁聚氯乙烯薄膜及制备方法。首先通过制备纳米二氧化硅水凝胶；然后将聚氯乙烯溶于丁酮,并利用丁酮易于水分散的特性,在高速搅拌下使聚氯乙烯分散为纳米粒,得到分散纳米二氧化硅和纳米聚氯乙烯的纳米浆料；在100-110℃的聚氯乙烯基膜喷涂纳米浆料,并通过表面镀有微米凸点的压辊压制,使纳米聚氯乙烯、纳米二氧化硅与基膜结合,同时形成的微米凹点使薄膜形成了微粗糙表面,而且微粗糙表面分布纳米颗粒；一方面构成的微粗糙结构类似于“荷叶”效应,赋予表面疏水性,同时,纳米二氧化硅表面分散有聚四氟乙烯,其材质疏水性良好,有效防止污染物粘附薄膜,具有自洁性。(The invention belongs to the field of functional plastic films, and particularly relates to a hydrophobic self-cleaning polyvinyl chloride film and a preparation method thereof. Firstly, preparing nano silicon dioxide hydrogel; then dissolving polyvinyl chloride in butanone, and dispersing the polyvinyl chloride into nanoparticles under high-speed stirring by utilizing the characteristic that the butanone is easy to disperse in water to obtain nano slurry in which nano silicon dioxide and nano polyvinyl chloride are dispersed; spraying nano slurry on a 100-plus-110-DEG C polyvinyl chloride-based film, pressing the polyvinyl chloride-based film by a press roller with the surface plated with micron convex points, so that the nano polyvinyl chloride and the nano silicon dioxide are combined with the base film, and simultaneously, the formed micron concave points enable the film to form a micro-rough surface, and the micro-rough surface is distributed with nano particles; on one hand, the formed micro-rough structure is similar to a lotus leaf effect, the surface is endowed with hydrophobicity, meanwhile, polytetrafluoroethylene is dispersed on the surface of the nano silicon dioxide, the material hydrophobicity is good, pollutants are effectively prevented from being adhered to the film, and the self-cleaning property is realized.)

1. A preparation method of a hydrophobic self-cleaning polyvinyl chloride film is characterized by comprising the following steps:

(1) dispersing 10-15 parts by weight of sodium methylsilicate in 40-50 parts by weight of water; then adding citric acid to adjust the pH value to 4-5; slowly stirring for 10-15min to form nano silicon dioxide dispersed hydrogel; then adding 1-3 parts by weight of polytetrafluoroethylene emulsion as a hydrophobic agent, and uniformly dispersing to obtain pretreated silicon dioxide hydrogel;

(2) dissolving and dispersing polyvinyl chloride in butanone in an amount which is 3 times the mass of the polyvinyl chloride to obtain polyvinyl chloride liquid; further adding monoglyceride accounting for 1-3% of the mass of the polyvinyl chloride solution, stirring at a high speed for dispersion, and simultaneously adding the pretreated silicon dioxide hydrogel obtained in the step (1) to obtain nano slurry;

(3) adding 100 parts by weight of film-grade polyvinyl chloride, 15-20 parts by weight of plasticizer, 1-2 parts by weight of heat stabilizer and 1-3 parts by weight of lubricant into a high-speed mixer, pre-dispersing at 60-80 ℃, then sending into a three-roller extrusion calendering device, and carrying out three-roller calendering to obtain a polyvinyl chloride base film; controlling the temperature of the base film passing through the calendering roller at 100-110 ℃; and (3) spraying the nano slurry obtained in the step (2) on the surface of a polyvinyl chloride film while the polyvinyl chloride film is hot, then pressing the polyvinyl chloride film by a press roller with the surface plated with micron convex points, drying and coiling the polyvinyl chloride film to obtain the hydrophobic self-cleaning polyvinyl chloride film.

2. The method for preparing a hydrophobic self-cleaning polyvinyl chloride film according to claim 1, wherein the method comprises the following steps: the polytetrafluoroethylene emulsion in the step (1) is a commercially available emulsion with the mass concentration of 20%.

3. The method for preparing a hydrophobic self-cleaning polyvinyl chloride film according to claim 1, wherein the method comprises the following steps: and (3) dissolving and dispersing the polyvinyl chloride in butanone in an amount which is 3 times the mass of the polyvinyl chloride in the step (2).

4. The method for preparing a hydrophobic self-cleaning polyvinyl chloride film according to claim 1, wherein the method comprises the following steps: in the step (2), the high-speed stirring dispersion is carried out at a high speed of 2000-5000rpm, and the stirring time is controlled to be more than 30 min.

5. The method for preparing a hydrophobic self-cleaning polyvinyl chloride film according to claim 1, wherein the method comprises the following steps: and (3) mixing the polyvinyl chloride liquid and the pretreated silicon dioxide hydrogel in the step (2) according to the mass ratio of 1: 1.

6. The method for preparing a hydrophobic self-cleaning polyvinyl chloride film according to claim 1, wherein the method comprises the following steps: the temperature of the base film in the step (3) is controlled at 100-110 ℃.

7. The method for preparing a hydrophobic self-cleaning polyvinyl chloride film according to claim 1, wherein the method comprises the following steps: the micron concave points formed by the micron convex points in the step (3) are hemispherical concave points with the diameter of 10-20 microns.

8. The method for preparing a hydrophobic self-cleaning polyvinyl chloride film according to claim 1, wherein the method comprises the following steps: in the step (3), PVC-SG2 is selected as the film-grade polyvinyl chloride; the plasticizer is at least one of dioctyl phthalate, dibutyl phthalate and dioctyl sebacate; the heat stabilizer is at least one of barium stearate and zinc stearate; and at least one of stearic acid, paraffin wax and polyethylene wax serving as the lubricant.

9. A hydrophobic self-cleaning polyvinyl chloride film prepared by the method of any one of claims 1 to 8.

Technical Field

The invention belongs to the field of functional plastic films, and particularly relates to a hydrophobic self-cleaning polyvinyl chloride film and a preparation method thereof.

Background

The polyvinyl chloride film is used as a low-cost plastic film and is widely applied in the fields of industry, agriculture, buildings and the like. The polyvinyl chloride film is mainly prepared by calendering and molding. Such as bags, raincoats, tablecloths, curtains; the wide transparent film can be used for greenhouses, plastic greenhouses and mulching films. Particularly in the fields of buildings, furniture protection, wind power and industrial and agricultural products, the polyvinyl chloride film can be used as a protective layer to effectively protect building components, wind power blades, industrial pipelines and the like.

In popularization and application, the polyvinyl chloride film is easy to be polluted, and attracts the attention of users. The skilled person finds that: the surface of the polyvinyl chloride film is not easy to clean, has poor self-cleaning performance, is easy to be sticky and dirty after being exposed for a long time. The reason is that the plasticizer is added into the polyvinyl chloride during processing, and the plasticizer is easy to wash out after film forming, so that the film is sticky and easy to adhere dust. In addition, polyvinyl chloride is a polar molecular chain, and the hydrophobicity of the film is poor, so that dust and the like are easy to adhere. Therefore, the polyvinyl chloride film is required to improve self-cleaning property and hydrophobicity as a protective film.

The technicians try to add hydrophobic materials such as waxy materials, silicone powder and the like in the processing of the polyvinyl chloride film, however, the waxy materials have poor compatibility and dispersibility in the polyvinyl chloride system and are separated out; in addition, plasticizer precipitation from polyvinyl chloride films affects the self-cleaning properties of the films, and reduction in plasticization and usage affects film processability.

Therefore, when the hydrophobicity and self-cleaning property of the polyvinyl chloride film are treated, breakthrough on the surface of the polyvinyl chloride film is critical. For example, a material which is similar to a micro-nano coarse structure and modifies low surface energy is constructed on the surface of polyvinyl chloride, so that the polyvinyl chloride film can be effectively endowed with excellent self-cleaning property and hydrophobicity. The Chinese patent publication No. CN 101993682B of the invention is still a super-hydrophobic polyvinyl chloride film, the surface of which has a structure of interweaving yarn sections, the super-hydrophobic polyvinyl chloride film is prepared by an electrostatic spinning method, and the super-hydrophobic polyvinyl chloride film is spun into a structure of alternating microspheres and yarn fusiform shapes to improve the hydrophobicity of polyvinyl chloride. However, the electrostatic spinning process is complex, the microstructure control difficulty is high, and the large-scale popularization and application are difficult.

Disclosure of Invention

At present, the polyvinyl chloride film has the defects that plasticizer is separated out, so that the film is easy to be sticky, has poor self-cleaning property and poor hydrophobicity, and the use of the polyvinyl chloride film as a protective film and a greenhouse film is influenced; in order to solve the problem, the invention firstly provides a hydrophobic self-cleaning polyvinyl chloride film and further provides a preparation method of the hydrophobic self-cleaning polyvinyl chloride film. Particularly, the hydrophobic microstructure is stably constructed on the surface of the polyvinyl chloride film, and the self-cleaning and the hydrophobicity of the polyvinyl chloride film are realized through a low-cost and simple process.

Firstly, a preparation method of a hydrophobic self-cleaning polyvinyl chloride film is provided, which is characterized by comprising the following steps:

(1) dispersing 10-15 parts by weight of sodium methylsilicate in 40-50 parts by weight of water; then adding citric acid to adjust the pH value to 4-5; slowly stirring for 10-15min to form nano silicon dioxide dispersed hydrogel; then adding 1-3 parts by weight of polytetrafluoroethylene emulsion as a hydrophobic agent, and uniformly dispersing to obtain pretreated silicon dioxide hydrogel;

(2) dissolving and dispersing polyvinyl chloride in butanone in an amount which is 3 times the mass of the polyvinyl chloride to obtain polyvinyl chloride liquid; further adding monoglyceride accounting for 1-3% of the mass of the polyvinyl chloride solution, stirring at a high speed for dispersion, and simultaneously adding the pretreated silicon dioxide hydrogel obtained in the step (1) to obtain nano slurry;

(3) adding 100 parts by weight of film-grade polyvinyl chloride, 15-20 parts by weight of plasticizer, 1-2 parts by weight of heat stabilizer and 1-3 parts by weight of lubricant into a high-speed mixer, pre-dispersing at 60-80 ℃, then sending into a three-roller extrusion calendering device, and carrying out three-roller calendering to obtain a polyvinyl chloride base film; controlling the temperature of the base film passing through the calendering roller at 100-110 ℃; and (3) spraying the nano slurry obtained in the step (2) on the surface of a polyvinyl chloride film while the polyvinyl chloride film is hot, then pressing the polyvinyl chloride film by a press roller with the surface plated with micron convex points, drying and coiling the polyvinyl chloride film to obtain the hydrophobic self-cleaning polyvinyl chloride film.

Preferably, the polytetrafluoroethylene emulsion in the step (1) is an emulsion with a mass concentration of 20% on the market; the hydrogel in the silicon dioxide hydrogel is dispersed in a nanometer mode, and after the hydrogel is dispersed with polytetrafluoroethylene emulsion, the hydrophobicity of the nanometer silicon dioxide can be improved in an auxiliary mode.

Preferably, the polyvinyl chloride is dissolved and dispersed in butanone 3 times the mass of the polyvinyl chloride in the step (2), and the butanone is easy to dissolve the polyvinyl chloride and is easy to disperse in water, so that the polyvinyl chloride is driven to disperse in a water-containing system to form nano polyvinyl chloride particles.

Preferably, the high-speed stirring dispersion in the step (2) is realized by stirring dispersion at a high speed of 2000-5000rpm, and the stirring time is controlled to be more than 30 min; and uniformly dispersing the polyvinyl chloride in the form of nano particles and nano silicon dioxide to form nano slurry by high-speed stirring. And mixing the polyvinyl chloride liquid and the pretreated silicon dioxide hydrogel in a mass ratio of 1: 1.

In the step (3), nano materials are placed on the surface of the polyvinyl chloride-based film, and the temperature of the base film is controlled at 100-110 ℃; firstly, polyvinyl chloride and silicon dioxide with dispersed nano particles are formed, and further, the polyvinyl chloride and the silicon dioxide are pressed by a press roller with the surface plated with micron convex points, so that the polyvinyl chloride and the silicon dioxide are combined with a base film, and the dispersed structure of the nano particles is changed; specifically, the micro bumps are pressed to form micro rough concave surfaces on the film, and the nano particles are distributed on the micro rough concave surfaces; on one hand, the formed micro-rough structure is similar to a lotus leaf effect, the surface is endowed with hydrophobicity, meanwhile, polytetrafluoroethylene is dispersed on the surface of the nano silicon dioxide, the material hydrophobicity is good, pollutants are effectively prevented from being adhered to the film, and the self-cleaning property is realized.

In particular, in a typical preferred embodiment, the micro-pits formed by the micro-bumps are hemispherical pits with a diameter of 10-20 μm. The pits are distributed in a close-packed arrangement.

Further preferably, the film grade polyvinyl chloride in the step (3) is PVC-SG 2.

Further preferably, in the step (3), the plasticizer is at least one selected from dioctyl phthalate, dibutyl phthalate and dioctyl sebacate.

Further preferably, in the step (3), at least one of barium stearate and zinc stearate is selected as the heat stabilizer.

Further preferably, in the step (3), at least one of stearic acid, paraffin wax and polyethylene wax is used as the lubricant.

Furthermore, the invention provides the hydrophobic self-cleaning polyvinyl chloride film prepared by the method. Firstly, preparing nano silicon dioxide hydrogel; then dissolving polyvinyl chloride in butanone, and dispersing the polyvinyl chloride into nanoparticles under high-speed stirring by utilizing the characteristic that the butanone is easy to disperse in water to obtain nano slurry in which nano silicon dioxide and nano polyvinyl chloride are dispersed; spraying nano slurry on a 100-plus-110-DEG C polyvinyl chloride-based film, pressing the polyvinyl chloride-based film by a press roller with the surface plated with micron convex points, so that the nano polyvinyl chloride and the nano silicon dioxide are combined with the base film, and simultaneously, the formed micron concave points enable the film to form a micro-rough surface, and the micro-rough surface is distributed with nano particles; on one hand, the formed micro-rough structure is similar to a lotus leaf effect, the surface is endowed with hydrophobicity, meanwhile, polytetrafluoroethylene is dispersed on the surface of the nano silicon dioxide, the material hydrophobicity is good, pollutants are effectively prevented from being adhered to the film, and the self-cleaning property is realized.

Compared with the prior processing technology of the polyvinyl chloride hydrophobic film, the hydrophobic self-cleaning polyvinyl chloride film and the preparation method thereof have the prominent characteristics that:

(1) the invention forms micro-roughness on the surface of the polyvinyl chloride film, the microstructure of the polyvinyl chloride film has hydrophobicity, and the microstructure is stable and easy to control.

(2) The invention prepares nano slurry dispersed with nano polyvinyl chloride and nano silicon dioxide, and the nano polyvinyl chloride and the nano silicon dioxide are pressed on the surface of the polyvinyl chloride film by hot adhesion, so that the polyvinyl chloride film is endowed with hydrophobic self-cleaning property.

(3) The preparation method has the advantages of simple preparation process, easily controlled process and low cost, can be used for preparing the hydrophobic self-cleaning polyvinyl chloride film in a large scale and is beneficial to market popularization.

Drawings

The invention is further described below with reference to the accompanying drawings:

FIG. 1 is a schematic structural diagram of a hydrophobic self-cleaning polyvinyl chloride film according to the present invention. Wherein 1 represents a polyvinyl chloride-based film; 2 represents a micron pit; and 3 represents nanoparticles (nano silicon dioxide and nano polyvinyl chloride).

Detailed Description

The following examples are intended to further illustrate the present invention, but not to limit the scope of the claims of the present invention.