A dispersion system, dispersion method and application for dispersing glass fibers

Abstract

The invention provides a dispersion system, a dispersion method and an application for dispersing glass fibers. The dispersion system comprises an aluminum salt solution and a nanocellulose suspension. The dispersion method comprises the following steps: firstly dispersing chopped glass fibers into an aluminum salt solution, treating the solution for a certain period of time, and obtaining a preliminary dispersion system. Then, the nanocellulose suspension is added into the preliminary dispersion system, stirred and dispersed, and a uniformly dispersed glass fiber dispersion suspension is formed. The invention adopts the aluminum salt solution and the nanocellulose to act together, and the advantages of the two are complementary and synergistic, which not only significantly improves the dispersibility of the glass fibers, but also improves the mechanical strength of the dried glass fiber products. The aluminum salt solution of the invention is easy to recycle, and the nanocellulose is a biomass source, which is green, environmentally friendly and renewable. The method of the invention is simple to operate, green and pollution-free, and has broad application prospects.

Description

[Technical field]

[0001] The invention belongs to the technical field of inorganic fiber dispersion, and in particular relates to a dispersion system, a dispersion method and an application thereof for dispersing glass fibers. [Background technology]

[0002] Glass fiber is an inorganic non-metallic fiber made from ore, and its chemical composition is mainly silicon dioxide and boron trioxide. Glass fiber has excellent properties such as non-combustibility, high dimensional stability, low thermal conductivity, good electrical insulation, good sound absorption, high tensile strength, and good chemical stability. The glass fiber sheet material made by wet papermaking technology is called glass fiber wet felt, which has the characteristics of uniform fiber dispersion, good flatness, high tear strength, and fast and uniform impregnation. It is increasingly widely used in traditional industrial sectors such as transportation, papermaking, aviation, aerospace, nuclear energy, weapons, and defense, high-tech and other fields.

[0003] Although there are various types of glass fiber wet mats, there are common requirements for product performance, which require that the fibers be evenly dispersed to ensure that the product has good flatness, high strength performance, etc. However, the surface of glass fiber is rough, the friction coefficient between fibers is very high (static friction coefficient is 0.6-0.9), the aspect ratio is relatively large, the fiber surface is highly hydrophobic, the hydrophilicity is poor, and the surface has unstable electronegativity, which makes the glass fiber easier to flocculate, and it is not easy to redisperse after flocculation. The uniform dispersion of fibers in water and the formation of a well-distributed network structure are the key to the excellent properties of glass fiber wet mats, and it has also become one of the key technologies for the production of glass fiber wet mats. Therefore, how to efficiently disperse glass fibers is an urgent problem to be solved in the manufacture of high-performance glass fiber wet mats.

[0004] At present, the following methods are mainly adopted to improve the dispersion performance of glass fiber: (1) by adding acid, the pH of the glass fiber suspension is reduced, thereby neutralizing a small amount of alkaline points on the surface of the glass fiber, reducing the charge attraction between the weak acid points, promoting the separation between the fibers, and improving the uniform dispersion in water; (2) by adding dispersants, the viscosity of the fiber suspension is increased, the freedom of the fibers in water is restricted, and at the same time, the molecules contain hydrophilic groups to increase their wettability to water. Commonly used dispersants include polyethylene oxide (PEO) and hydroxyethyl cellulose (HEC); (3) by adding surfactants, the zeta potential of the glass fiber surface is regulated, or by treating with solvents or solutions, the surface free energy of the fibers is adjusted, the electrostatic interaction between the fibers is reduced, and the dispersion effect of the fibers is improved. Commonly used ones include cationic quaternary ammonium surfactants, hexadecyl dimethylamine, sodium hexametaphosphate (SHP), alcohol solution of silane coupling agent, phenol-tetrachloroethane, chloroform, etc.

[0005] Although these methods have effectively improved the dispersion of fibers, they also have certain problems: for example, equipment corrosion caused by lowering pH, increased drainage time caused by increased viscosity, foaming caused by the addition of surfactants, and reduced performance of wet-laid mat products caused by the addition of solvents, etc. Therefore, how to achieve more efficient and environmentally friendly dispersion of glass fibers is still an urgent problem to be solved. [Summary of the invention]

[0006] The object of the present invention is to provide a dispersion system, a dispersion method and an application for dispersing glass fibers which are easy to operate, efficient and environmentally friendly.

[0007] Based on the above objectives, a first aspect of the present invention is to provide a dispersion system for dispersing glass fibers, comprising an aluminum salt solution and a nanocellulose suspension.

[0008] Preferably, the aluminum salt solution is selected from one of aluminum sulfate solution and aluminum chloride solution.

[0009] Preferably, the concentration of the aluminum salt solution is 0.01-0.5%.

[0010] Preferably, the nanocellulose suspension is selected from a nanocellulose microfibril suspension or a bacterial cellulose suspension having a large aspect ratio.

[0011] A second aspect of the present invention is to provide a method for dispersing glass fibers using the dispersion system, comprising the following steps:

[0012] (1) Dispersing the chopped glass fibers into a solution containing an aluminum salt and treating for a certain period of time to obtain a preliminary dispersion system;

[0013] (2) Adding the nanocellulose suspension to the preliminary dispersion system, stirring and dispersing the system, and forming a uniformly dispersed glass fiber suspension.

[0014] Preferably, the dispersion concentration of the chopped glass fibers in the aluminum salt solution in step (1) is 0.001 to 1%.

[0015] Preferably, the treatment time in step (1) is 30 seconds to 10 minutes.

[0016] Preferably, the added volume of the nanocellulose suspension is 0.1-10% of the preliminary dispersion system in step (1).

[0017] Preferably, the stirring and dispersing time in step (2) is 10s to 5min.

[0018] The third aspect of the present invention is to provide application of the dispersion system or the dispersion method in preparing glass fiber wet mat.

[0019] Beneficial effects of the present invention:

[0020] Al in aluminum salt solution 3+ It can form a uniform water-slip film on the surface of glass fiber, reduce the friction on the surface of glass fiber, and reduce the entanglement between fibers; at the same time, the electrokinetic charge of aluminum ions on the fiber surface gives the glass fiber a positive charge, so that the glass fibers have a certain Zeta potential, which improves the dispersibility of the glass fiber; in addition, the aluminum salt solution can reduce the pH of the glass fiber dispersion to a certain extent, improving the dispersibility of the glass fiber;

[0021] Nanocellulose has good dispersibility and suspension stability, as well as a large specific surface area. It can be adsorbed and flocculated on the surface of glass fibers. It has good hydrophilic properties and can effectively improve the dispersibility of glass fibers.

[0022] The present invention adopts aluminum salt solution and nanocellulose to act together, and the advantages of the two are complementary and synergistic, which not only significantly improves the dispersibility of glass fiber, but also improves the mechanical strength of the glass fiber products after drying.

[0023] The aluminum salt solution of the present invention is easy to recycle, the nanocellulose is a biomass source, is green, environmentally friendly and renewable, and the method of the present invention is simple to operate, green and pollution-free, and has broad application prospects. [Specific implementation method]

[0024] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described by the following specific embodiments, but is by no means limited thereto. The following are preferred embodiments of the present invention, which are only used to describe the present invention and cannot be understood as limiting the present invention. It should be pointed out that any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0025] The concentrations of bacterial cellulose suspension and nanocellulose microfibril suspension in the following examples are all 1%.

[0026] Example 1

[0027] Disperse the glass fiber into a 0.01% aluminum sulfate solution, stir and disperse for 10 minutes to form a preliminary dispersion system containing 0.1% glass fiber;

[0028] Add 0.1% bacterial cellulose suspension by volume to the preliminary dispersion system, and stir and disperse for 5 minutes to obtain a uniformly dispersed glass fiber suspension.

[0029] Example 2

[0030] Disperse the glass fiber into a 0.05% aluminum sulfate solution, stir and disperse for 5 minutes to form a preliminary dispersion system containing 0.05% glass fiber;

[0031] Add 1% of the volume of the nanocellulose microfibril suspension into the preliminary dispersion system, and stir and disperse for 3 minutes to obtain a uniformly dispersed glass fiber suspension.

[0032] Example 3

[0033] Disperse the glass fiber into a 0.1% aluminum sulfate solution, stir and disperse for 1 minute to form a preliminary dispersion system containing 0.02% glass fiber;

[0034] Add 5% bacterial cellulose suspension by volume to the preliminary dispersion system, and stir and disperse for 1 minute to obtain a uniformly dispersed glass fiber suspension.

[0035] Example 4

[0036] Disperse the glass fiber into a 0.1% aluminum chloride solution, stir and disperse for 1 minute to form a preliminary dispersion system containing 0.02% glass fiber;

[0037] Add 5% bacterial cellulose suspension by volume to the preliminary dispersion system, and stir and disperse for 1 minute to obtain a uniformly dispersed glass fiber suspension.

[0038] Example 5

[0039] Disperse the glass fiber into a 0.2% aluminum sulfate solution, stir and disperse for 1 minute to form a preliminary dispersion system containing 0.001% glass fiber;

[0040] Add 5% of the volume of the nanocellulose microfibril suspension into the preliminary dispersion system, and stir and disperse for 1 minute to obtain a uniformly dispersed glass fiber suspension.

[0041] Example 6

[0042] Disperse the glass fiber into a 0.3% aluminum sulfate solution, stir and disperse for 30 seconds to form a preliminary dispersion system containing 1% glass fiber;

[0043] Add 10% bacterial cellulose suspension by volume into the preliminary dispersion system, and stir and disperse for 3 minutes to obtain a uniformly dispersed glass fiber suspension.

[0044] Comparative Example 1

[0045] The same as Example 3, except that, in this comparative example, the glass fibers are directly dispersed into the aqueous solution; specifically, the glass fibers are dispersed into the aqueous solution, stirred and dispersed for 1 minute, to form a preliminary dispersion system containing 0.02% of the glass fibers;

[0046] A bacterial cellulose suspension accounting for 5% of the volume of the preliminary dispersion system was added, and the glass fiber dispersion suspension was obtained by stirring and dispersing for 1 minute.

[0047] Comparative Example 2

[0048] The same as Example 3, except that in this comparative example, bacterial cellulose suspension is no longer added to the preliminary dispersion system; specifically, the glass fiber is dispersed in a 0.1% aluminum sulfate solution, stirred and dispersed for 1 minute to form a preliminary dispersion system containing a glass fiber concentration of 0.02%, and then stirred and dispersed for 1 minute to obtain a glass fiber dispersion suspension.

[0049] Comparative Example 3

[0050] The same as Example 3, except that the present comparative example uses a nanocellulose crystal suspension instead of a bacterial cellulose suspension; specifically, the glass fiber is dispersed in a 0.1% aluminum sulfate solution, stirred and dispersed for 1 min, to form a preliminary dispersion system containing a glass fiber concentration of 0.02%;

[0051] Add 5% of the volume of the nanocellulose crystal suspension into the preliminary dispersion system, and stir and disperse for 1 minute to obtain a glass fiber dispersion suspension.

[0052] Comparative Example 4

[0053] The glass fibers were dispersed using a commonly used glass fiber dispersion system. Specifically, the glass fibers were dispersed in a hydroxyethyl cellulose solution (C=0.03%) and hexadecyltrimethylammonium bromide (C=0.06%) at a concentration of 0.02%, and the mixture was stirred and dispersed for 2 minutes.

[0054] Glass fiber performance test:

[0055] The test method for the dispersion effect of the glass fiber of the present invention is as follows: The glass fiber suspensions dispersed in Examples 1 to 6 and Comparative Examples 1 to 4 are respectively sheeted and formed using a Frank PTI sheeter, with a quantitative weight of 80 g / m 2 After sizing and drying, the uniformity and strength properties of the glass fiber wet mat were measured.

[0056] The uniformity performance was tested using a paper uniformity tester (2D LAB F / SENSOR, Germany) and expressed as the uniformity index, which refers to the number of flocs per square meter of paper, in units of Flocs / m 2The smaller the uniformity index is, the fewer the floccules are per unit area of ​​the glass fiber wet felt, which means that the dispersion effect of the glass fiber is better; the larger the uniformity index is, the more the floccules are per unit area of ​​the glass fiber wet felt, which means that the dispersion effect of the glass fiber is worse.

[0057] The strength properties of glass fiber wet mat are characterized by tensile index, and the testing standard is GB / T 12914-2018.

[0058] Table 1 Test results of wet felts made from glass fiber suspensions of Examples and Comparative Examples

[0059] project <![CDATA[Evenness Index (Flocs / m 2 )]]> Tensile index (Nm / g) Example 1 21 18.5 Example 2 19 20.3 Example 3 11 22.4 Example 4 17 21.3 Example 5 14 22.8 Example 6 16 21.7 Comparative Example 1 69 14.8 Comparative Example 2 73 15.7 Comparative Example 3 70 16.0 Comparative Example 4 25 16.6

[0060] It can be seen from the results in Table 1 that the dispersion performance of the glass fiber suspension dispersed by the method of the present invention and the strength performance of the glass fiber wet mat prepared by using the method are higher than those of the control groups, indicating that the method of the present invention is highly feasible;

[0061] By comparing Example 3 and Example 4 of the present invention, it is found that aluminum sulfate has a better dispersion effect than aluminum chloride. However, the dispersion effect and the reinforcement effect on the glass fiber wet mat of Example 4 are still higher than those of the prior art. In reality, you can choose one according to your needs.

[0062] In addition, by comparing the embodiments of the present invention with comparative examples 1 and 2, it can be found that the use of aluminum salt solution or nanocellulose suspension alone cannot achieve efficient dispersion of glass fibers. After the present invention uses a suitable amount of the two in combination, the dispersibility and the tensile index of the obtained wet felt are significantly improved, indicating that the combination of the two has a significant synergistic effect.

[0063] In addition, by comparing the embodiments of the present invention with Comparative Example 3, it can be found that bacterial cellulose and nanocellulose microfibrils with a larger aspect ratio have a better dispersion effect than nanocellulose crystals with a smaller aspect ratio, and have a better reinforcing effect on the strength of the glass fiber wet mat.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dispersion system for dispersing glass fibers, characterized in that: including an aluminum salt solution and a nanocellulose suspension; The aluminum salt solution is selected from one of aluminum sulfate solution and aluminum chloride solution; The concentration of the aluminum salt solution is 0.01-0.5%; The nanocellulose suspension is selected from a nanocellulose microfibril suspension with a large aspect ratio or a bacterial cellulose suspension.

2. The method for dispersing glass fibers using the dispersion system of claim 1, characterized in that: The steps include: (1) Dispersing the chopped glass fibers into a solution containing aluminum salt and treating for a certain period of time to obtain a preliminary dispersion system; (2) Adding the nanocellulose suspension to the preliminary dispersion system described in step (1), stirring and dispersing the suspension to form a uniformly dispersed glass fiber suspension.

3. The method for dispersing glass fibers according to claim 2, characterized in that: The dispersion concentration of the chopped glass fibers in the aluminum salt solution in step (1) is 0.001-1%.

4. The method for dispersing glass fibers according to claim 2, characterized in that: The processing time described in step (1) is 30s~10min.

5. The method for dispersing glass fibers according to claim 2, characterized in that: The added volume of the nanocellulose suspension is 0.1-10% of the preliminary dispersion system in step (1).

6. The method for dispersing glass fibers according to claim 2, characterized in that: The stirring and dispersing time in step (2) is 10s~5min.

7. Use of the dispersed system according to claim 1 or the method according to claim 2 in preparing glass fiber wet mat.