阅读说明：本技术 一种疏水浆料及其制备方法与应用 (Hydrophobic slurry and preparation method and application thereof ) 是由 吴敏 刘金凤 李金培 黄勇 于 2019-10-17 设计创作，主要内容包括：本发明涉及高分子材料技术领域,具体公开了一种疏水浆料及其制备方法与应用。所述疏水浆料包括：疏水纤维素和作为成膜剂的疏水高分子；所述疏水纤维素为表面包覆含氟聚合物的纤维素；所述含氟聚合物为聚四氟乙烯、聚偏氟乙烯、氟化乙烯丙烯共聚物或乙烯三氟氯乙烯中的一种或多种；所述疏水高分子为聚乙烯醇缩丁醛、乙基纤维素、聚己内酯、聚乳酸中的一种或多种。该疏水浆料组分简单、制备简便、无需化学改性,赋予了亲水材料优异的疏水性能。本发明还提供一种上述疏水浆料的制备方法,该方法简便、利于工业化生产。本发明另提供一种疏水纸,其包含上述疏水浆料,其制备简便,具备良好的疏水性能及力学性能。(The invention relates to the technical field of high polymer materials, and particularly discloses hydrophobic slurry and a preparation method and application thereof. The hydrophobic paste includes: hydrophobic cellulose and hydrophobic polymer as film forming agent; the hydrophobic cellulose is cellulose with the surface coated with fluoropolymer; the fluorine-containing polymer is one or more of polytetrafluoroethylene, polyvinylidene fluoride, fluorinated ethylene propylene copolymer or ethylene chlorotrifluoroethylene; the hydrophobic polymer is one or more of polyvinyl butyral, ethyl cellulose, polycaprolactone and polylactic acid. The hydrophobic slurry has simple components, is simple and convenient to prepare, does not need chemical modification, and endows the hydrophilic material with excellent hydrophobic property. The invention also provides a preparation method of the hydrophobic slurry, which is simple and convenient and is beneficial to industrial production. The invention also provides hydrophobic paper which comprises the hydrophobic sizing agent, is simple and convenient to prepare and has good hydrophobic property and mechanical property.)

1. A hydrophobic paste, comprising: hydrophobic cellulose and hydrophobic polymer as film forming agent; the hydrophobic cellulose is cellulose with the surface coated with fluoropolymer;

the fluorine-containing polymer is one or more of polytetrafluoroethylene, polyvinylidene fluoride, fluorinated ethylene propylene copolymer or ethylene chlorotrifluoroethylene;

the hydrophobic polymer is one or more of polyvinyl butyral, ethyl cellulose, polycaprolactone and polylactic acid.

2. The hydrophobic paste of claim 1, wherein the fluoropolymer is polytetrafluoroethylene.

3. The hydrophobic slurry according to claim 1 or 2, wherein the hydrophobic polymer is a mixture of the polylactic acid and the ethyl cellulose, and the mass ratio of the polylactic acid to the ethyl cellulose is 1: (1-5), preferably 1: (2.5-3.5).

4. The hydrophobic pulp according to any one of claims 1 to 3, wherein the hydrophobic cellulose is obtained by mixing a cellulose material and the fluoropolymer and then grinding, and the mass ratio of the cellulose material to the fluoropolymer is 1: (15-25); the grinding speed is 240-580 rpm; the grinding time is 1-36 h; the cellulose material is natural cellulose or regenerated cellulose.

5. The hydrophobic pulp according to any one of claims 1 to 4, wherein the mass ratio of the hydrophobic cellulose to the hydrophobic macromolecule is 1: (0.3 to 1.7), preferably 1: (0.6-1.6).

6. A method of making the hydrophobic paste of any one of claims 1-5, comprising:

(1) mixing the hydrophobic polymer with an organic solvent to prepare a hydrophobic polymer solution;

(2) and mixing the hydrophobic polymer solution with the hydrophobic cellulose to prepare the hydrophobic slurry.

7. The method according to claim 6, wherein the organic solvent is one or more of ethyl acetate, dichloromethane, acetone, and ethanol.

8. The method according to claim 6 or 7, wherein the mass ratio of the hydrophobic polymer to the organic solvent is 1: (19-99), preferably 1: (19 to 50).

9. Use of the hydrophobic paste of any one of claims 1-5 or the method of any one of claims 6-8 for the preparation of hydrophobic paper.

10. Hydrophobic paper, characterized in that it comprises the hydrophobic pulp according to any of claims 1-5.

Technical Field

The invention relates to the field of high polymer materials. In particular to hydrophobic slurry and a preparation method and application thereof.

Background

Hydrophobicity is an important surface property of the material, and the hydrophobic property is provided for the solid material in different modes, so that the solid material has new additional functions, can be widely applied and replaces products with obvious defects in the prior art.

For example, plastic products have good hydrophobic and water-resistant properties, are widely applied to various fields of production and life, but are difficult to degrade, bring increasingly serious white pollution, and restrict the use of the plastic products. The paper products are mature in preparation process and degradable, and are widely used in life to replace plastic products, but paper-based materials (paper boxes, paper main component shopping bags, gift packaging boxes and the like) are easy to break when meeting water, and the service environment and the service life are greatly limited, so that the application field of the paper-based materials is expanded by endowing the paper-based materials with hydrophobic performance conventionally at present. In the prior art, most of the hydrophobic paper is prepared by using a chemical method, and the surface of the paper is modified by reagents such as organic silicon and organic fluorine, or hydrophobic polymers are grafted on the surface of the paper to perform hydrophobic modification on the paper. In addition, the paper product is endowed with hydrophobic performance by coating/laminating the fluorine-containing and silicon-containing hydrophobic coating, but in the preparation process of the coating, the fluorine-containing and silicon-containing agent is mainly used for modifying resins such as epoxy resin, acrylic resin and the like, various additives and fillers are added, the process is complex, most of the used additives are harmful to the environment, and the used resins are not biodegradable, so that the environmental pollution is aggravated.

Therefore, there is a need to provide a new way to impart hydrophobic properties to solid materials to solve the problems in the prior art.

Disclosure of Invention

In order to solve some or all of the problems in the prior art, a first object of the present invention is to provide a hydrophobic slurry (for hydrophilic interface) and a preparation method thereof, wherein the hydrophobic slurry has simple components, easily available materials, simple preparation and no need of chemical modification.

The second purpose of the invention is to provide the hydrophobic sizing agent and the application of the preparation method thereof in preparing hydrophobic paper.

The third purpose of the invention is to provide a hydrophobic paper containing the hydrophobic pulp and the hydrophobic pulp prepared by the method.

In order to achieve the first object of the present invention, the technical solution of the present invention is as follows:

a hydrophobic paste comprising: hydrophobic cellulose and hydrophobic polymer as film forming agent; the hydrophobic cellulose is cellulose with the surface coated with fluoropolymer;

the fluorine-containing polymer is one or more of polytetrafluoroethylene, polyvinylidene fluoride, fluorinated ethylene propylene copolymer or ethylene chlorotrifluoroethylene;

the hydrophobic polymer is one or more of polyvinyl butyral, ethyl cellulose, polycaprolactone and polylactic acid.

Conventional hydrophobic surfaces have been made hydrophobic by grafting low surface energy materials, such as silanes, fluorosilanes, etc., onto the surface of the material. The method replaces strong polar groups such as-OH on the surface of the material, and a low surface energy surface is formed through chemical reaction between molecules where hydrophobic groups are located and the surface or a matrix material. This method is complicated in steps (in order to reduce the consumption of modified molecules, the surface and substrate are usually treated sufficiently before modification to reduce the moisture content), and requires many chemicals, and is harsh, and difficult to industrialize. However, the conventional method of applying hydrophobic coatings to impart hydrophobic properties to the surface of materials has many problems, such as: the coating needs to be modified in the preparation process, a large amount of fluorine-containing and silicon-containing reagents, various auxiliaries and fillers are used, the components are numerous, the process is complex, and the large-scale industrial production is not facilitated.

The hydrophobic cellulose adopted by the invention has excellent hydrophobic property because the surface of the hydrophobic cellulose is coated with the fluorine-containing polymer, but the application of the hydrophobic cellulose on a hydrophilic surface cannot be realized by adopting a conventional film forming agent because the surface of the hydrophobic cellulose is coated with the hydrophobic substance in a large area and a small amount of hydroxyl groups are exposed. A large number of tests show that the hydrophobic macromolecules (polyvinyl butyral, ethyl cellulose, polycaprolactone and polylactic acid) are used as the film forming agent, so that the specific hydrophobic cellulose can be fully dispersed and formed on the surface of the base material, the obtained hydrophobic slurry is uniform in property, the hydrophobic cellulose can form a compact hydrophobic layer under the action of the macromolecules, water molecules can be effectively prevented from entering the base material, the water absorption performance of the base material is greatly reduced, and meanwhile, the surface of the base material is provided with a rugged coating surface caused by the hydrophobic cellulose, so that the water contact angle can be increased, and the hydrophobic performance of the base material is further improved. That is, the hydrophobic cellulose provides roughness and a low energy surface to the surface to be treated, giving the substrate the desired hydrophobic properties. The hydrophobic slurry only comprises two components, the components are simple and easy to obtain, a chemical modification process is not needed, ideal hydrophobic performance can be provided for various base materials, and large-scale popularization and application are facilitated.

In the invention, the molecular weight of the polytetrafluoroethylene is 500-600 ten thousand; the molecular weight of the polyvinylidene fluoride is 40-50 ten thousand; the molecular weight of the fluorinated ethylene propylene copolymer is 70-100 ten thousand; the molecular weight of the ethylene chlorotrifluoroethylene is 50-70 ten thousand; the molecular weight of the polyvinyl butyral is 4-7 ten thousand; the molecular weight of the ethyl cellulose is 1-3 ten thousand; the molecular weight of the polycaprolactone is 1-5 ten thousand; the molecular weight of the polylactic acid is 5-6 ten thousand.

Preferably, the fluoropolymer is polytetrafluoroethylene to provide better hydrophobic properties to the application surface.

Preferably, the hydrophobic cellulose is cellulose with a surface uniformly coated with polytetrafluoroethylene.

In the present invention, preferably, the hydrophobic polymer is degradable hydrophobic polymer ethyl cellulose, polycaprolactone, or polylactic acid. The hydrophobic cellulose adhesive provides better adhesive property, is biodegradable, can not cause environmental pollution when being matched with the same biodegradable hydrophobic cellulose, and meets the requirement of environmental protection.

In the invention, the hydrophobic polymer is a mixture of the polylactic acid and the ethyl cellulose, the polylactic acid and the cellulose have excellent compatibility, can be tightly combined with the fiber of the invention, and can be compounded with the ethyl cellulose, so that the film forming property is better than that of the polylactic acid alone; the mass ratio of the polylactic acid to the ethyl cellulose is 1: (1-5), preferably, when the mass ratio of the polylactic acid to the ethyl cellulose is 1: (2.5-3.5), compared with a hydrophobic polymer with a single component, the water-proof polymer has the comprehensive advantages of better water-proof performance and tensile strength; more preferably, the mass ratio of the polylactic acid to the ethylcellulose is 1: 3.

In the invention, the hydrophobic cellulose is prepared by mixing the cellulose material and the fluorine-containing polymer and then grinding, wherein the grinding speed is 240-580 rpm; the grinding time is 1-36 h; the cellulose material is natural cellulose or regenerated cellulose. The mass ratio of the cellulosic material to the fluoropolymer is 1: (15-25) to ensure that the fluoropolymer can completely coat the cellulosic material.

As a preferable mode, the grinding speed is 540 rpm; the grinding time is 8-12 h.

The natural cellulose is selected from natural herbaceous plants or natural woody plants; the regenerated cellulose is selected from one or more of viscose, cuprammonium fiber, tencel or alkali urea solution fiber.

The preparation raw material of the hydrophobic cellulose, namely the cellulose, is widely available in nature, has high yield, is renewable and biodegradable, is prepared by a one-pot physical mixing mode, avoids pollution caused by chemical modification, and is an ideal material for providing hydrophobicity for the surface of a base material.

According to the invention, the particle size of the hydrophobic cellulose can be regulated and controlled through the change of grinding parameters, the adjustable range of the transverse and longitudinal sizes of the particles is 5-200 μm, the adjustable range of the particle thickness is 0.4-10 μm, the water contact angle is 70-120 degrees, and the expected hydrophobic performance can be provided for the hydrophobic slurry according to specific requirements.

The invention obtains the micro-nano hydrophobic cellulose after grinding, which is beneficial to providing a compact hydrophobic layer for the application surface.

Specifically, the preferred preparation method is as follows:

grinding the dried cellulose material and the fluorine-containing polymer in a ball mill or a grinding instrument, wherein the grinding speed is 240-580rpm, and the grinding time is 1-36 h; after grinding, the surface of the cellulose material is uniformly coated with the fluorine-containing polymer, and redundant fluorine-containing polymer is separated and removed to obtain the hydrophobic cellulose.

The ball mill is selected from a planetary ball mill or a vibratory ball mill. The grinding instrument is a mortar type grinding instrument.

The cellulose material can be crushed and dried before being ground with the fluorine-containing polymer, and the crushed cellulose material is a section material with the length of 2-5mm and the width of 1-2mm, so as to be beneficial to compounding with the fluorine-containing polymer.

As a preferred embodiment, when the hydrophobic cellulose is prepared as follows: after mixing the cellulose material and the fluorine-containing polymer, grinding is carried out, the grinding speed is 540rpm, the grinding time is 12h, and the hydrophobic polymer is a mixture of polylactic acid and ethyl cellulose with the mass ratio of 1:3, so that a better hydrophobic effect and excellent tensile strength can be endowed to an application object (paper).

In the present invention, the mass ratio of the hydrophobic cellulose to the hydrophobic polymer is 1: (0.3 to 1.7), preferably 1: (0.6-1.6), the paper can be endowed with excellent comprehensive performance while ensuring uniform mixing.

In a preferred embodiment of the present invention, the film forming agent is a mixture of polylactic acid and ethylcellulose, the mass ratio of the film forming agent to the polylactic acid is 1 (2.5-3.5), and the mass ratio of the hydrophobic cellulose to the hydrophobic polymer is 1: (0.6-1.6).

As a preferred embodiment, the film forming agent is a mixture of polylactic acid and ethyl cellulose with a mass ratio of 1:3, and the mass ratio of the hydrophobic cellulose to the hydrophobic macromolecule is 1: 1.6. this approach can provide a highly hydrophobic effect to the substrate surface with contact angles in excess of 130 °.

In addition, the research shows that the super-hydrophobic coating can be prepared by adding a small amount of nano particles (gas-phase nano silicon dioxide, hydrophobic nano cellulose and the like).

The invention also provides a method for preparing the hydrophobic sizing agent, which comprises the following steps:

(1) mixing the hydrophobic polymer with an organic solvent to prepare a hydrophobic polymer solution;

(2) and mixing the hydrophobic polymer solution with the hydrophobic cellulose to prepare the hydrophobic slurry.

All the steps of the hydrophobic slurry preparation can be carried out at room temperature, the components can be fully mixed and dispersed only by stirring, the preparation is simple and convenient, and the hydrophobic slurry can be industrially popularized on a large scale.

Preferably, the organic solvent is one or more of ethyl acetate, dichloromethane, acetone and ethanol (an organic solvent capable of dissolving the hydrophobic macromolecules adopted can be selected correspondingly according to the technical common knowledge in the field), preferably ethyl acetate and dichloromethane, so as to be more beneficial to the dissolution and dispersion of various macromolecules of the invention, further to ensure that the hydrophobic cellulose of the invention has good dispersibility and good film forming property, so that the prepared hydrophobic slurry has more uniform property, and provides more ideal hydrophobicity and toughening effect for the surface to be treated.

In the method of the present invention, the mass ratio of the hydrophobic polymer to the organic solvent is 1: (19-99). As the concentration of the hydrophobic macromolecule increases, the overall viscosity of the hydrophobic slurry increases and the settling time increases, preferably 1: (19-50) is more beneficial to preparation and application.

In order to achieve the second object of the present invention, the present invention also provides a use of the above hydrophobic pulp or the above method for preparing hydrophobic paper.

In order to achieve the third object of the present invention, the present invention further provides a hydrophobic paper, which comprises the above hydrophobic pulp.

The hydrophobic paper of the invention has high hydrophobic property and excellent tensile property.

Preferably, when the selected hydrophobic polymer is a degradable hydrophobic polymer, the paper coated with the hydrophobic sizing agent can be completely degraded in nature, and does not bring negative influence to the environment.

In the present invention, the hydrophobic slurry may be coated, sprayed onto a paper product, or a paper product may be soaked into the hydrophobic slurry, or otherwise combined with the hydrophobic slurry to produce the hydrophobic paper. The preparation process is simple and feasible, and can meet different industrial production requirements.

The invention has the beneficial effects that:

when the problem of hydrophobic modification of the surface of a base material is faced, the complex process of grafting hydrophobic macromolecules on the surface to be treated is abandoned, a coating containing non-degradable resin and a large amount of auxiliary agents is not adopted, the hydrophobic slurry which is simpler, more convenient and more environment-friendly and can provide hydrophobic performance for the base material is provided, the components are simple and easily obtained, chemical modification is not needed in the preparation process, and when ethyl cellulose, polycaprolactone and polylactic acid are used as film forming agents, the hydrophobic slurry can be further completely biodegraded without bringing burden to the environment.

The preparation of the hydrophobic slurry does not need to adopt a large amount of auxiliary agents which are not beneficial to environmental protection, the process is simple and convenient, the stirring at room temperature can be completed, the cost is low, and the preparation method is beneficial to large-scale popularization and application.

The hydrophobic paper is simple and convenient to prepare, has excellent water resistance, is low in water absorption rate, is further increased in strength due to the hydrophobic pulp (the hydrophobic pulp can enter the paper base so as to effectively enhance the strength of the paper base material), can be used for replacing plastic products and relieving the generation of white pollution.

Drawings

FIG. 1 is a scanning electron micrograph of the surfaces of paper and a blank reference paper according to example 1 of the present invention; wherein, fig. 1a and fig. 1b are scanning electron microscope images of the surface of blank control paper which is not coated with the hydrophobic sizing agent of the invention; FIGS. 1c and 1d are scanning electron micrographs of the surface of the paper prepared in example 1 of the present invention;

FIG. 2 is a result of a hydrophobic property test of the hydrophobic papers prepared in examples 1 to 8 of the present invention; wherein the ordinate is Contact angle (Contact angle), and the abscissa is hydrophobic polymer concentration; FIG. 2a shows the test results of examples 1 to 4, and FIG. 2b shows the test results of examples 5 to 8;

FIG. 3 shows the results of paper tensile testing of a blank control and hydrophobic papers made according to examples 1-8 of the present invention; wherein the ordinate is Tensile strength (Tensile strength), and the abscissa is hydrophobic polymer concentration; FIG. 3a shows the results of the tests of the blank control and examples 1-4, and FIG. 3b shows the results of the tests of the blank control and examples 5-8;

FIG. 4 shows the results of the hydrophobic property tests of the hydrophobic papers prepared in examples 9 to 17 of the present invention; wherein, the ordinate is the contact angle, and the abscissa represents the mass percent concentration (Content/%) of the compound hydrophobic macromolecule in the hydrophobic macromolecule solution;

FIG. 5 is a result of a hydrophobic property test of a blank control and hydrophobic papers prepared in comparative examples 1 to 4 of the present invention; wherein the ordinate is the contact angle and Blank represents the Blank control;

FIG. 6 shows the results of paper tensile testing of a blank control and hydrophobic papers made in examples 9-17 of the present invention; wherein, the ordinate is tensile strength, and the abscissa represents the mass percentage concentration of the compound hydrophobic macromolecule in the hydrophobic macromolecule solution;

FIG. 7 shows the results of paper tensile testing of a blank control versus the hydrophobic papers prepared in comparative examples 1-4 of the present invention; where the ordinate is tensile strength and Blank represents Blank.

Detailed Description

Preferred embodiments of the present invention will be described in detail with reference to the following examples. It is to be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the present invention. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of this invention.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified. Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.