Ceramic fiber layered separator and preparation method thereof

Abstract

The invention relates to the technical field of ceramic composite materials, and particularly discloses a ceramic fiber layered partition plate and a preparation method thereof. The ceramic fiber layered thermal insulation board comprises the following raw materials in parts by weight: 50 parts of ceramic fibers, 10-50 parts of micro-nano glass fibers, 1-10 parts of an adhesive, 70-90 parts of a modified inorganic thermal insulation filler, 30-50 parts of an infrared shading filler and 500-1000 parts of water. The ceramic fiber layered partition plate provided by the invention is high in structural stability, high in durability, particularly high in water resistance and excellent in heat insulation performance, and can be applied to the field of high-temperature heat insulation for a long time.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic composite materials, and specifically discloses a ceramic fiber laminated separator and a preparation method thereof. Background Art

[0002] Thermal insulation is one of the important measures to achieve energy conservation and ensure sustainable economic development. With the development of high-temperature industries, higher requirements are put forward for thermal insulation materials, such as high efficiency, energy conservation, high strength, low thermal conductivity, and waterproofing. The existing technologies have been seeking and researching new high-temperature industrial thermal insulation materials with low thermal conductivity, high infrared reflectivity, and microporosity. Ceramic fiber is a fibrous lightweight refractory material. The thermal insulation material made of it has the advantages of high temperature resistance, good thermal stability, low thermal conductivity, and resistance to mechanical vibration, and thus has been widely used in industries such as machinery, metallurgy, petrochemical, building materials, and electronics. The differences in the composition and structure of ceramic fibers directly determine the high and low temperature strength, creep resistance, elastic modulus, etc. of the fibers. The length of the fibers determines the final form of the fiber products and determines the respective application fields of different fiber products. With the increasing requirements of more and more application scenarios, there is still room for further improvement in the performance of existing ceramic fiber materials.

[0003] The invention patent with the publication number CN105347798A discloses a ceramic fiber heat insulation board. The ceramic fiber heat insulation board is made of the following raw materials in parts by weight: 3-5 parts of nano-titanium dioxide, 4-9 parts of nano-aluminum oxide, 2-8 parts of vanadium pentoxide, 5-7 parts of nano-silicon carbide, 35-45 parts of micron-sized silicon carbide, 1-5 parts of dispersant, 3-4 parts of zirconium latex, 4-8 parts of dolomite powder, and 30-40 parts of micron-sized aluminum oxide. The ceramic fiber heat insulation board has high infrared reflectivity on the premise of meeting high temperature resistance. Its bulk density and high-temperature thermal conductivity are low, and it has excellent heat insulation performance. At the same time, its excellent flexural strength can be used in the high-temperature heat insulation field for a long time. However, this invention uses inorganic binders sodium silicate and calcium carbonate as dispersants, and due to the limitation of their environmentally sensitive properties, it may affect the durability of the ceramic fiber heat insulation board. Summary of the Invention

[0004] Aiming at the defects of the existing technology, the present invention discloses a ceramic fiber laminated separator and a preparation method thereof. The ceramic fiber laminated separator provided by the present invention has high structural stability, strong durability, especially water resistance, and excellent heat insulation performance, and can be used in the high-temperature heat insulation field for a long time.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] On the one hand, the present invention provides a ceramic fiber laminated separator, and the separator comprises raw materials in the following parts by weight: 50 parts of ceramic fiber, 10 - 50 parts of micro-nano glass fiber, 1 - 10 parts of adhesive, 70 - 90 parts of modified inorganic heat-insulating filler, 30 - 50 parts of infrared light-shielding filler, and 500 - 1000 parts of water.

[0007] In some embodiments of the present invention, the fiber diameter of the ceramic fiber is 0.3 - 20 μm, and the fiber length is 1 - 50 mm.

[0008] Preferably, the fiber diameter of the ceramic fiber is 8 - 15 μm, and the fiber length is 10 - 30 mm.

[0009] In some embodiments of the present invention, the fiber diameter of the micro-nano glass fiber is 0.9 - 10 μm, and the fiber length is 3 - 50 mm.

[0010] Preferably, the fiber diameter of the micro-nano glass fiber is 2 - 6 μm, and the fiber length is 15 - 30 mm.

[0011] In some embodiments of the present invention, the adhesive is a modified polyurethane, and the preparation steps of the modified polyurethane are as follows:

[0012] Mix a polyurethane prepolymer, a solvent, and an emulsifier, add itaconic acid and stir to mix, adjust the pH to 4 - 5, heat up to 60 - 70 °C, then add initiator 1 and stir and react for 2 - 3 h, then add 3 - 5 wt% of silica sol, continue to heat up to 75 - 90 °C, react for 1 - 2 h, and cool to room temperature to obtain the modified polyurethane.

[0013] In some embodiments of the present invention, the mass ratio of polyurethane, itaconic acid, and silica in 3 - 5 wt% of silica sol is 1:(0.1 - 0.6):(0.05 - 0.1).

[0014] Preferably, the mass ratio of polyurethane, itaconic acid, and silica in 3 - 5 wt% of silica sol is 1:0.35:0.07.

[0015] In the prior art, polyurethane adhesives are a very common type of organic adhesives. In order to ensure the long-term resistance of the ceramic laminated separator, its water resistance needs to be further improved. In view of this, the water resistance of the modified polyurethane prepared in this application is significantly increased. The possible reason is that the carboxyl groups on the introduced itaconic acid undergo an esterification reaction in the system to form new chemical bonds, thereby reducing the proportion of hydrophilic hydrogen bonds. The additional reaction sites provided by the silica sol participate in the efficient chemical bonding reaction in the system, synergistically enhancing the interaction force of the modified polyurethane, further blocking water vapor and reducing water infiltration, thereby improving the strength and water resistance of the ceramic laminated separator and ensuring the more long-term performance of the ceramic laminated separator.

[0016] In some embodiments of the present invention, the preparation steps of the modified inorganic heat-insulating filler are as follows:

[0017] Mix starch and vinyltriethoxysilane, add an organic solvent, heat up to 60-75°C, stir and react for 1-3 h, then add an inorganic heat-insulating filler and initiator 2, and stir at a constant temperature for 1-4 h. After washing and drying, the modified inorganic heat-insulating filler is obtained.

[0018] In some embodiments of the present invention, the inorganic heat-insulating filler is at least one of silica aerogel, silica nano, and hollow glass microspheres.

[0019] In some embodiments of the present invention, the mass ratio of starch, vinyltriethoxysilane, and inorganic heat-insulating filler is (1-3):(0.5-1):10.

[0020] Preferably, the mass ratio of starch, vinyltriethoxysilane, and inorganic heat-insulating filler is 2:0.75:10.

[0021] In the prior art, inorganic heat-insulating fillers and ceramic fibers are often compounded to prepare partition materials, but there are often problems that the performance of the partition materials is poor due to the poor dispersibility of the inorganic heat-insulating fillers. In the prior art, a dispersant is often added to promote the effective dispersion of the inorganic heat-insulating fillers on the one hand and improve the problem of poor compatibility when the inorganic fillers are mixed with organic components on the other hand, but this often generates new deficiencies, that is, the heat-insulating performance of the heat-insulating fillers is easily affected by the performance of the dispersant.

[0022] In the present invention, starch is modified by adding vinyltriethoxysilane, and the modified starch is loaded onto the inorganic heat-insulating filler. First, the coating and infiltration effects of the inorganic heat-insulating filler in the system are improved, and the bonding strength of the layered partition is further improved. The introduction of vinyltriethoxysilane greatly improves the dispersibility of the inorganic heat-insulating filler loaded with modified starch in the system. At the same time, it may be due to the esterification reaction between the hydroxyl groups on the starch and the itaconate groups on the modified polyurethane, which further improves the cohesion between the components in the system and improves the comprehensive performance of the ceramic layered partition.

[0023] In some embodiments of the present invention, the infrared light-shielding filler is one or more of silicon carbide, titanium dioxide, barium titanate whiskers, and graphite.

[0024] On the other hand, the present invention also provides a method for preparing a ceramic fiber layered partition, comprising the following steps:

[0025] S1: Add ceramic fibers, micro-nano glass fibers, and an adhesive to water, and obtain an aqueous slurry through homogeneous dispersion;

[0026] S2: Filter and mold the aqueous slurry to obtain two layers of thin wet fiber blanks. Uniformly sprinkle the modified inorganic heat-insulating filler and infrared light-shielding filler between the two layers of thin wet fiber blanks, and then press, dry, and calcine to obtain the ceramic fiber laminated separator.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] (1) The ceramic fiber laminated separator provided by the present invention has high structural stability, strong durability, especially strong water resistance, and excellent heat insulation performance, and can be used in the field of high-temperature heat insulation for a long time.

[0029] (2) The present invention introduces itaconic acid and silica sol to modify polyurethane, significantly improving the interaction force of the modified polyurethane, further blocking water vapor and reducing water infiltration, thereby improving the strength and water resistance of the ceramic laminated separator and ensuring the more long-term performance of the ceramic laminated separator.

[0030] (3) The present invention modifies starch by adding vinyltriethoxysilane and loads the modified starch onto the inorganic heat-insulating filler. First, it improves the coating and infiltration of the inorganic heat-insulating filler in the system, further improving the bonding strength of the laminated separator. The introduction of vinyltriethoxysilane greatly improves the dispersibility of the inorganic heat-insulating filler loaded with modified starch in the system. At the same time, it may be due to the esterification reaction between the hydroxyl groups on the starch and the itaconate groups on the modified polyurethane, further improving the cohesion between the components in the system and improving the comprehensive performance of the ceramic laminated separator. Specific Embodiments

[0031] The following will describe the present invention in conjunction with specific implementation examples. It should be noted that the following examples are examples of the present invention and are only used to illustrate the present invention, rather than to limit the present invention. Other combinations and various improvements within the concept of the present invention can be made without departing from the main idea or scope of the present invention.

[0032] Unless otherwise specified, the reagents used below can be easily obtained from commercial companies. The polyurethane prepolymer used is purchased from Shanghai Hecheng High Polymer Technology Co., Ltd. The ceramic fibers (fiber diameter is 10 μm, fiber length is 25 mm) and micro-nano glass fibers (fiber diameter is 5 μm, fiber length is 22 mm) used are all from Jiaxing Furui Bang New Material Technology Co., Ltd.

[0033] Unless otherwise specified, the post-treatment steps such as "washing", "drying", and "homogeneous dispersion" used below are conventional operations for those skilled in the art and can be selected according to actual operations; the 4wt% silica sol used can be prepared by means well-known to those skilled in the art, and the present invention does not make special limitations.

[0034] Unless otherwise specified, the inorganic heat-insulating fillers used hereinafter are all hollow glass microspheres (particle size: 30 μm), and the infrared light-shielding fillers used are all silicon carbide.

[0035] Preparation Example 1

[0036] The preparation steps of the modified polyurethane are as follows:

[0037] Mix 1 g of polyurethane prepolymer, 20 mL of water and 0.6 g of sodium dodecyl sulfate, add 0.35 g of itaconic acid and stir to mix, adjust the pH to 4, heat up to 65 °C, then add 0.03 g of ammonium persulfate, stir and react for 2.5 h, then add 0.075 g of 4 wt% silica sol, continue to heat up to 80 °C, react for 1.5 h, and cool to room temperature to obtain the modified polyurethane.

[0038] Preparation Example 2

[0039] The preparation steps of the modified polyurethane are the same as those in Preparation Example 1, the difference being that the addition amount of itaconic acid used is 0.9 g.

[0040] Preparation Example 3

[0041] The preparation steps of the modified polyurethane are the same as those in Preparation Example 1, the difference being that the addition amount of 4 wt% silica sol used is 0.13 g.

[0042] Preparation Example 4

[0043] The preparation steps of the modified inorganic heat-insulating filler are as follows:

[0044] Mix 2 g of corn starch and 0.75 g of vinyltriethoxysilane, add 30 mL of ethanol and 10 mL of water, heat up to 65 °C, stir and react for 2 h, then add 10 g of inorganic heat-insulating filler and 0.02 g of ammonium persulfate, stir at a constant temperature for 2.5 h, and obtain the modified inorganic heat-insulating filler after washing and drying.

[0045] Preparation Example 5

[0046] The preparation steps of the modified inorganic heat-insulating filler are the same as those in Preparation Example 4, the difference being that the addition amount of corn starch used is 4 g.

[0047] Preparation Example 6

[0048] The preparation steps of the modified inorganic heat-insulating filler are the same as those in Preparation Example 4, the difference being that the addition amount of vinyltriethoxysilane used is 1.25 g.

[0049] Example 1

[0050] A ceramic fiber laminated separator comprises the following raw materials in parts by weight: 50 parts of ceramic fiber, 30 parts of micro-nano glass fiber, 5.5 parts of adhesive, 80 parts of modified inorganic heat-insulating filler, 40 parts of infrared light-shielding filler and 750 parts of water.

[0051] The preparation method of the ceramic fiber laminated separator in this embodiment includes the following steps:

[0052] S1: Add ceramic fiber, micro-nano glass fiber, and adhesive into water, and obtain an aqueous slurry through homogeneous dispersion.

[0053] S2: Subject the aqueous slurry to suction filtration and molding to obtain two layers of thin-layer fiber green compacts. Uniformly sprinkle the modified inorganic heat-insulating filler and infrared light-shielding filler between the two layers of thin-layer fiber green compacts, and then press them at a pressure of 3 MPa to obtain a prototype, dry them at 100 °C to constant weight, and calcine them at 700 °C for 4 h to obtain the ceramic fiber laminated separator.

[0054] The adhesive used in this embodiment is obtained from Preparation Example 1, and the modified inorganic heat-insulating filler used is obtained from Preparation Example 4.

[0055] Example 2

[0056] A ceramic fiber laminated separator contains the following raw materials in parts by weight: 50 parts of ceramic fiber, 10 parts of micro-nano glass fiber, 1 part of adhesive, 70 parts of modified inorganic heat-insulating filler, 30 parts of infrared light-shielding filler, and 500 parts of water.

[0057] The preparation method of the ceramic fiber laminated separator in this embodiment includes the following steps:

[0058] S1: Add ceramic fiber, micro-nano glass fiber, and adhesive into water, and obtain an aqueous slurry through homogeneous dispersion.

[0059] S2: Subject the aqueous slurry to suction filtration and molding to obtain two layers of thin-layer fiber green compacts. Uniformly sprinkle the modified inorganic heat-insulating filler and infrared light-shielding filler between the two layers of thin-layer fiber green compacts, and then press them at a pressure of 0.3 MPa to obtain a prototype, dry them at 50 °C to constant weight, and calcine them at 300 °C for 5 h to obtain the ceramic fiber laminated separator.

[0060] The adhesive used in this embodiment is obtained from Preparation Example 1, and the modified inorganic heat-insulating filler used is obtained from Preparation Example 4.

[0061] Example 3

[0062] A ceramic fiber laminated separator contains the following raw materials in parts by weight: 50 parts of ceramic fiber, 50 parts of micro-nano glass fiber, 10 parts of adhesive, 90 parts of modified inorganic heat-insulating filler, 50 parts of infrared light-shielding filler, and 1000 parts of water.

[0063] The preparation method of the ceramic fiber laminated separator in this embodiment includes the following steps:

[0064] S1: Add ceramic fiber, micro-nano glass fiber, and adhesive into water, and obtain an aqueous slurry through homogeneous dispersion.

[0065] S2: Filter the aqueous slurry by suction filtration and press it by molding to obtain two layers of thin-layer fiber green blanks. Uniformly sprinkle the modified inorganic heat-insulating filler and the infrared light-shielding filler between the two layers of thin-layer fiber green blanks, and then press it at a pressure of 5 MPa to obtain a prototype, dry it to constant weight at 150 °C, and calcine it at 1100 °C for 3 h to obtain the ceramic fiber laminated separator.

[0066] The adhesive used in this example is obtained from Preparation Example 1, and the modified inorganic heat-insulating filler used is obtained from Preparation Example 4.

[0067] Example 4

[0068] A ceramic fiber laminated separator and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the adhesive used is obtained from Preparation Example 2.

[0069] Example 5

[0070] A ceramic fiber laminated separator and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the adhesive used is obtained from Preparation Example 3.

[0071] Example 6

[0072] A ceramic fiber laminated separator and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the modified inorganic heat-insulating filler used is obtained from Preparation Example 5.

[0073] Example 7

[0074] A ceramic fiber laminated separator and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the modified inorganic heat-insulating filler used is obtained from Preparation Example 6.

[0075] Example 8

[0076] A ceramic fiber laminated separator and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the adhesive used is a commercially available polyurethane adhesive, purchased from Dongguan Jiudian Adhesive Industry Co., Ltd.

[0077] Comparative Example 1

[0078] A ceramic fiber laminated separator and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the modified inorganic heat-insulating filler is replaced with an equal amount of inorganic heat-insulating filler.

[0079] Performance Test

[0080] Take the ceramic fiber laminated separators obtained in Examples 1-8 and Comparative Example 1 above for the following performance tests. The specific test results are shown in Table 1:

[0081] (1) Glue strength test: Tensile strength test was carried out on the ceramic fiber laminated separator according to the test of Class III plywood in the standard GB / T 17657-2013 to characterize the glue strength of the ceramic fiber laminated separator;

[0082] (2) Water resistance test: Each ceramic fiber laminated separator was sawn into small pieces of 2.5 cm × 2.5 cm and immersed in warm water at (60 ± 3) °C. The time when the ceramic fiber laminated separator started to delaminate was recorded as the water resistance time;

[0083] (3) Heat insulation performance test: The thermal conductivity of the ceramic fiber laminated separator at 1000 °C was measured to characterize the heat insulation performance of the ceramic fiber laminated separator.

[0084]

[0085]

[0086] As can be seen from Table 1, the ceramic fiber laminated separators provided in Examples 1-3 of the present invention have stable structure, strong durability and good heat insulation performance.

[0087] By comparing Example 4 with Example 1, it can be seen that when the addition amount of itaconic acid for preparing the adhesive-modified polyurethane changes, the glue strength and water resistance of the ceramic fiber laminated separator will both decrease, and the heat insulation performance is less affected.

[0088] By comparing Example 5 with Example 1, it can be seen that when the addition amount of silica sol for preparing the adhesive-modified polyurethane changes, the performance of the ceramic fiber laminated separator after soaking in warm water becomes worse and the water resistance time is shorter.

[0089] By comparing Example 6 with Example 1, it can be seen that when the addition amount of corn starch in the prepared modified inorganic heat insulation filler changes, the viscosity of the system is greatly affected, which in turn leads to poor glue strength of the ceramic fiber laminated separator and a decrease in heat insulation performance.

[0090] By comparing Example 7 with Example 1, it can be seen that when the addition amount of vinyltriethoxysilane in the prepared modified inorganic heat insulation filler changes, the glue strength, water resistance and heat insulation performance of the ceramic fiber laminated separator will all decrease, which is caused by poor system stability.

[0091] By comparing Example 8 with Example 1, it can be seen that when polyurethane is directly added as an adhesive, due to the poor water resistance of polyurethane, the glue strength and water resistance of the ceramic fiber laminated separator both become worse.

[0092] By comparing Comparative Example 1 with Example 1, it can be seen that when inorganic heat insulation filler is directly added, its dispersibility in the system will decrease sharply, which in turn leads to a decrease in the modification effect on the system and affects the comprehensive performance of the ceramic fiber laminated separator.

[0093] As described above, it is only the preferred embodiment of the present invention and does not impose any formal limitations on the present invention. Although the present invention has been disclosed above with the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art, within the scope of the technical solution of the present invention, can make some changes or modifications to the equivalent embodiments by using the above-disclosed technical content. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A ceramic fiber layered separator, characterized in that: The partition comprises the following raw materials in parts by weight: 50 parts of ceramic fiber, 10 to 50 parts of micro-nano glass fiber, 1 to 10 parts of adhesive, 70 to 90 parts of modified inorganic heat-insulating filler, 30 to 50 parts of infrared light-shielding filler and 500 to 1000 parts of water.

2. The ceramic fiber layered separator according to claim 1, characterized in that: The fiber diameter of the ceramic fiber is 0.3-20 μm, and the fiber length is 1-50 mm.

3. The ceramic fiber layered separator according to claim 1, characterized in that: The fiber diameter of the micro-nano glass fiber is 0.9-10 μm, and the fiber length is 3-50 mm.

4. The ceramic fiber layered separator according to claim 1, characterized in that: The adhesive is a modified polyurethane, and the preparation steps of the modified polyurethane are as follows: Mix the polyurethane prepolymer, solvent and emulsifier, add itaconic acid and stir to mix, adjust the pH to 4-5, heat to 60-70°C, add initiator 1, stir to react for 2-3h, add 3-5wt% silica sol, continue to heat to 75-90°C, react for 1-2h, and cool to room temperature to obtain modified polyurethane.

5. The ceramic fiber layered separator according to claim 4, characterized in that: The mass ratio of the polyurethane prepolymer, itaconic acid and 3-5wt% of silicon dioxide in silica sol is 1:(0.1-0.6):(0.05-0.1).

6. The ceramic fiber layered separator according to claim 1, characterized in that: The preparation steps of the modified inorganic thermal insulation filler are as follows: Mix starch and vinyl triethoxysilane, add organic solvent, heat to 60-75°C, stir and react for 1-3 hours, then add inorganic thermal insulation filler and initiator 2, stir at constant temperature for 1-4 hours, wash and dry to obtain modified inorganic thermal insulation filler.

7. The ceramic fiber layered separator according to claim 6, characterized in that: The inorganic heat-insulating filler is at least one of silica aerogel, silica nano and hollow glass microspheres.

8. The ceramic fiber layered separator according to claim 6, characterized in that: The mass ratio of the starch, vinyl triethoxysilane and inorganic thermal insulation filler is (1-3): (0.5-1):

10.

9. The ceramic fiber layered separator according to claim 1, characterized in that: The infrared light-shielding filler is one or more of silicon carbide, titanium dioxide, barium titanate whisker and graphite.

10. A method for preparing a ceramic fiber layered separator according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: adding ceramic fiber, micro-nano glass fiber and adhesive into water, and homogenizing and dispersing them to obtain aqueous slurry; S2: The aqueous slurry is filtered and molded to obtain two thin fiber wet blanks, and the modified inorganic thermal insulation filler and infrared light-shielding filler are evenly spread between the two thin fiber wet blanks, and then pressed, dried and calcined to obtain the ceramic fiber layered separator.

Images