Ceramic binder, ceramic slurry and ceramic sheet

Abstract

The application provides a ceramic binder, which comprises a polymer containing polar structural units, hard structural units and flexible structural units; the hard structural units have a glass transition temperature Tg1 of 80 DEG C or above; the flexible structural units have a glass transition temperature Tg2 of 0 DEG C or below; in the polymer, the mass ratio of the polar structural units, the flexible structural units and the hard structural units is (1-5):(35-65):(35-65); and the hydroxyl content in the polymer is less than 0.1 wt%. The ceramic binder prepared by the application has good performance, stable viscosity of ceramic slurry, high tensile strength and good flexibility of the ceramic sheet after casting.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of low temperature co-fired ceramics, and particularly relates to a ceramic binder, a ceramic slurry and a ceramic sheet. BACKGROUND

[0002] Low temperature co-fired ceramics (LTCC) as an important branch in the field of modern electronic packaging plays an irreplaceable role in the construction of high-frequency, high-speed and high-density electronic systems due to its excellent electrical properties, mechanical strength, thermal stability and processability.

[0003] The manufacturing process of LTCC generally includes the following steps: firstly, the ceramic powder is subjected to ball milling and dispersion treatment, then a plasticizer and a binder are added, and the ball milling and mixing are continued, and after the defoaming treatment, a ceramic slurry composition with suitable viscosity is obtained. Then, a doctor blade, an inverse roll coater or the like is used for flow casting. After removing the volatile components such as solvents by heating or the like, the ceramic sheet is peeled off from the base film. The conductive paste for forming the internal electrode is coated on the obtained ceramic sheet by using a screen printing process, the coated ceramic sheet is alternately stacked in multiple layers, and is subjected to heating and pressure bonding to form a laminated body. Subsequently, the adhesive resin components in the laminated body are subjected to thermal decomposition treatment (i.e., defatting treatment) to remove these components. Thereafter, the ceramic sintered body is obtained through a sintering process, and the external electrode is sintered on the end surface, and finally a laminated ceramic capacitor is manufactured.

[0004] In the field of LTCC technology, the glass / ceramic composite system is the most widely used system at present, and among them, the borate glass system with B2O3-SiO2 as the main component has attracted much attention due to its ability to significantly reduce the sintering temperature. In the traditional preparation process, the binder is generally polyvinyl butyral resin (PVB). However, when PVB binder is used in the borate glass system, the stability of the prepared slurry is low, and the key performance of the ceramic sheet after flow casting, such as tensile strength, is insufficient.

[0005] Therefore, it is of great significance to develop a ceramic binder suitable for flow casting of borate-containing ceramic for improving the production efficiency and product quality of LTCC. SUMMARY

[0006] In order to solve the problem that the existing PVB ceramic binder has low stability and is prone to thickening when used in the borate glass system with B2O3-SiO2 as the main component, the application provides a ceramic binder, a ceramic slurry and a ceramic sheet.

[0007] The purpose of the application is achieved by the following technical solutions.

[0008] In a first aspect, the present application provides a ceramic binder, which comprises a polymer containing polar structural units, hard structural units and flexible structural units.

[0009] The glass transition temperature Tg1 of the hard structural units is above 80℃; and the glass transition temperature Tg2 of the flexible structural units is below 0℃.

[0010] In the polymer, the mass ratio of the polar structural units, the flexible structural units and the hard structural units is (1-5):(35-65):(35-65).

[0011] In the polymer, the content of hydroxyl groups is less than 0.1wt%.

[0012] Preferably, the polar structural units include any one or a combination of at least two of carboxylic acid type structural units, amide type structural units and sulfonic acid type structural units.

[0013] Preferably, the hard structural units include any one or a combination of at least two of acrylate type structural units, aromatic vinyl type structural units and nitrile type structural units.

[0014] Preferably, the flexible structural units include polyether type acrylate structural units.

[0015] Preferably, the weight average molecular weight of the polyether type acrylate structural units is 1000-4000, and / or the glass transition temperature Tg2 of the polyether type acrylate structural units is -10--90℃.

[0016] Preferably, the flexible structural units are selected from one or more of polyethylene glycol monomethyl ether acrylate structural units, polyethylene glycol monoethyl ether acrylate structural units, polyethylene glycol monomethyl ether methacrylate structural units, polyethylene glycol monoethyl ether methacrylate structural units and polypropylene glycol monomethyl ether methacrylate structural units.

[0017] Preferably, the glass transition temperature Tg of the polymer is 0-30℃; and / or the weight average molecular weight of the polymer is 15w-30w.

[0018] In a second aspect, the present application provides a ceramic slurry, which comprises a ceramic powder and the aforementioned ceramic binder.

[0019] Preferably, the content of B2O3 in the ceramic powder is 20wt%-40wt%; the flexible structural units of the polymer in the ceramic binder include polyether type acrylate structural units; and the content of the polyether type acrylate structural units is 15%-35% of the content of B2O3.

[0020] Preferably, the ceramic slurry has a solid content of 45% to 60% and a viscosity of 1000 to 8000 cp.

[0021] In a third aspect, the present application provides a ceramic sheet prepared from the aforementioned ceramic slurry.

[0022] When the conventional PVB binder is used in the borate glass system, the prepared slurry has low stability and is prone to thickening, which is not conducive to subsequent processing, and the key performance of the ceramic sheet after casting, such as tensile strength, is insufficient. The inventors of the present application speculate that the reason may be that a large number of hydroxyl groups in PVB easily interact with B2O3 in the glass powder, resulting in thickening of the slurry and performance degradation.

[0023] In the present application, a hard monomer and a soft monomer with a specific glass transition temperature are used in combination with a polar monomer, and the specific content of the three is matched, to obtain a polymer having a polar structural unit, a flexible structural unit and a hard structural unit by polymerization. Since the monomers used do not contain hydroxyl groups, the obtained polymer also does not contain hydroxyl groups. The ceramic slurry prepared from the ceramic binder has high stability and improves the problem of thickening. At the same time, due to the structural unit with the above specific glass transition temperature and content composition in the polymer, the problems of low tensile strength and toughness of the ceramic sheet are improved. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and beneficial effects solved by the present application clearer and more apparent, the present application will be further described in detail below in combination with specific embodiments. It should be understood that the embodiments described herein are part of the embodiments of the present application, rather than all the embodiments, and are used to explain the present application, but not to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0025] In a first aspect, the present application provides a ceramic binder, comprising a polymer containing a polar structural unit, a hard structural unit and a flexible structural unit; the glass transition temperature Tg1 of the hard structural unit is above 80℃; the glass transition temperature Tg2 of the flexible structural unit is below 0℃; in the polymer, the mass ratio of the polar structural unit, the flexible structural unit and the hard structural unit is (1-5):(35-65):(35-65); and the content of hydroxyl groups in the polymer is below 0.1wt%.

[0026] In the present application, the polar structural unit includes any one or a combination of at least two of a carboxylic acid structural unit, an amide structural unit, and a sulfonic acid structural unit. Preferably, the polar structural unit includes any one or a combination of at least two of an amide structural unit and a carboxylic acid structural unit.

[0027] It should be noted that, in the present application, the -OH group in the carboxyl group in the above-mentioned carboxylic acid structural unit is not considered to be the hydroxyl group as described above, and the spatial structure and charge environment of the -OH group in the carboxyl group are different from those of a conventional simple hydroxyl group (for example, the hydroxyl group in PVB). As is well known to those skilled in the art, the two can be distinguished directly from infrared characteristic peaks for polymers.

[0028] Specifically, the polar structural unit includes any one or a combination of at least two of an acrylic acid structural unit, a methacrylic acid structural unit, an acrylamide structural unit, a methacrylamide structural unit, and a 2-acrylamido-2-methylpropanesulfonic acid structural unit.

[0029] In the present application, the glass transition temperature Tg1 of the hard structural unit is 80°C or higher, and is preferably 80-130°C. Specifically, the hard structural unit includes any one or a combination of at least two of an acrylate structural unit, an aromatic vinyl structural unit, and a nitrile structural unit.

[0030] In some specific embodiments, the hard structural unit includes any one or a combination of at least two of a methyl methacrylate structural unit, an isobornyl methacrylate structural unit, a t-butyl methacrylate structural unit, a styrene structural unit, an α-methylstyrene structural unit, an acrylonitrile structural unit, and a methacrylonitrile structural unit.

[0031] In the present application, the glass transition temperature Tg2 of the flexible structural unit is 0°C or lower.

[0032] According to the present application, as a preferred case, the flexible structural unit includes a polyether acrylate structural unit. Specifically, the flexible structural unit is preferably selected from one or more of a polyethylene glycol monomethyl ether acrylate structural unit, a polyethylene glycol monoethyl ether acrylate structural unit, a polyethylene glycol monomethyl ether methacrylate structural unit, a polyethylene glycol monoethyl ether methacrylate structural unit, and a polypropylene glycol monomethyl ether methacrylate structural unit.

[0033] To further improve the tensile strength and elongation at break of the ceramic sheet, the weight average molecular weight of the polyether acrylate structural unit is 1000-4000. More preferably, the degree of polymerization of the polyether acrylate structural unit is 20-80.

[0034] In addition, the glass transition temperature Tg2 of the polyether acrylate structural unit is -10~ -90℃, and is further preferably -30~ -70℃.

[0035] The mass ratio of the polar structural unit, the flexible structural unit and the hard structural unit in the polymer is (1~5):(35~65):(35~65).

[0036] Specifically, the mass ratio of the polar structural unit, the flexible structural unit and the hard structural unit can be 5:35:60, 5:40:55, 5:50:45, 5:60:35, 1:65:34, 2:55:43, 3:47:50, or 4:51:45, etc.

[0037] In the present application, the polar structural unit, the hard structural unit and the flexible structural unit are obtained by polymerization of polar monomers, hard monomers and soft monomers, respectively. Among them, the monomers exist in the form of corresponding structural units in the polymer obtained by polymerization. The glass transition temperature, mass ratio and molecular weight of each type of structural unit are based on the glass transition temperature, mass ratio and molecular weight of the corresponding monomers.

[0038] Each type of monomer can be obtained by commercial purchase. For example, for the aforementioned soft monomer, a monomer with corresponding parameters can be purchased according to the required molecular weight, polymerization degree and Tg2.

[0039] In some embodiments, the glass transition temperature Tg of the polymer is 0~30℃.

[0040] Specifically, the glass transition temperature Tg of the polymer can be 0℃, 5℃, 10℃, 14℃, 18℃, 20℃, 25℃ or 30℃, etc.

[0041] In some embodiments, the weight average molecular weight of the polymer is 15w~30w.

[0042] Specifically, the weight average molecular weight of the polymer can be 15w, 20w, 22.5w, 26w, 28w or 30w, etc.

[0043] In some embodiments, the tensile strength of the adhesive film of the polymer prepared is 20~40 MPa, and the elongation at break is 50%~100%.

[0044] The polymer of the present application can be prepared by a conventional free radical polymerization method. For example, the preparation method can be:

[0045] The polar monomer, soft monomer and hard monomer are mixed in proportion, an initiator and a solvent are added, and reaction is carried out at 60-70℃ for 3-5h, then the temperature is increased to 75-80℃, an initiator is added again, and reaction is continued for 5-7h, to obtain the polymer of the ceramic binder. The initiator can be azobisisobutyronitrile, and the addition amount is 0.5-2% of the total mass of the monomers. The solvent can be ethyl acetate, and the addition amount is 1.5-2 times of the total mass of the monomers.

[0046] It can be understood that, in the polymer and the preparation method thereof provided by the present application, no monomer or component containing a hydroxyl group is added, and therefore the content of the hydroxyl group in the polymer is necessarily less than 0.1wt%, and the polymer can be considered as containing no hydroxyl group.

[0047] In a second aspect, the present application provides a ceramic slurry, comprising a ceramic powder and the aforementioned ceramic binder.

[0048] Preferably, the content of B2O3 in the ceramic powder is 20wt%-40wt%; the flexible structural unit of the polymer in the ceramic binder comprises a polyether acrylate structural unit; and the content of the polyether acrylate structural unit is 15%-35% of the content of B2O3. At this time, it is very beneficial to further improve the tensile strength and elongation at break of the ceramic sheet.

[0049] The preparation method of the ceramic slurry of the present application is as follows:

[0050] a) The ceramic powder, a solvent and a dispersant are first ball-milled for 2-4h, and the mass ratio of the raw materials (the ceramic powder, the solvent and the dispersant) to the grinding body is 1-3:1; the content of B2O3 in the ceramic powder is 20wt%-40wt%; the solvent is ethyl acetate, and the addition amount is 75-85% of the mass of the ceramic powder; and the dispersant is oleic acid, and the addition amount is 0.5-2% of the mass of the ceramic powder;

[0051] b) The ceramic binder prepared by the present application and a plasticizer are added again, the addition amount of the ceramic binder (calculated according to the amount of the polymer) is 10-20% of the mass of the ceramic powder, the plasticizer is dioctyl phthalate, and the addition amount is 2-4% of the mass of the ceramic powder, and secondary ball-milling is carried out for 8-12h, to obtain the ceramic slurry.

[0052] In some specific embodiments, the solid content of the prepared ceramic slurry is 45%-60%, and the viscosity is 1000-8000cp.

[0053] In a third aspect, the present application provides a ceramic sheet, comprising the aforementioned ceramic slurry. The ceramic slurry prepared by the present application is cast into a ceramic sheet on a full-automatic casting machine.

[0054] In some embodiments, the tensile strength of the prepared ceramic sheet is 6-15 MPa, and the elongation at break is 6%-10%.

[0055] The specific embodiments of the present application will be further explained by the following examples and comparative examples.

[0056] The reagents, materials and instruments used in the following description are conventional reagents, conventional materials and conventional instruments, which are commercially available, and the reagents involved can also be synthesized by conventional synthesis methods. The methods in the examples are conventional methods in the art, unless otherwise specified. The monomers meeting the present application can be commercially available.

[0057] The glass transition temperature can be detected by GB / T 19466.1-2004 differential scanning calorimeter (DSC). The molecular weight of the polymer can be determined by gel permeation chromatography (GPC).

[0058] Example 1:

[0059] 1) Preparation of ceramic binder:

[0060] In a reaction kettle, 5 parts of acrylic acid, 40 parts of polyethylene glycol monomethyl ether acrylate (Tg2 is-65℃, weight average molecular weight is 2000, and polymerization degree is 40), 55 parts of methyl methacrylate (Tg1 is 105℃) are mixed, 0.5 parts of azobisisobutyronitrile is added, 200 parts of ethyl acetate is added, and the reaction is carried out at 70℃ for 4 h; the temperature is raised to 75℃, and 0.5 parts of azobisisobutyronitrile is added again, and the reaction is continued for 6 h to obtain a ceramic binder containing a polymer. The glass transition temperature of the polymer is 15℃, and the weight average molecular weight is 15.8 w.

[0061] 2) Preparation of ceramic slurry

[0062] a) In a ball mill tank, the ceramic powder, solvent and dispersant are initially ball milled for 3 h, and the mass ratio of raw materials (ceramic powder, solvent and dispersant) to grinding body is 2:1; the mass ratio of B2O3:SiO2:Al2O3 in the ceramic powder is 3:4:3, and the content of B2O3 in the ceramic powder is 30wt%; the solvent is ethyl acetate, and the amount of addition is 85% of the mass of the ceramic powder; the dispersant is oleic acid, and the amount of addition is 1% of the mass of the ceramic powder;

[0063] b) adding the ceramic binder prepared in the application and plasticizer into the ball mill tank, the amount of ceramic binder (based on the amount of polymer) is 15% of the mass of ceramic powder, the plasticizer is dioctyl phthalate, and the amount is 3% of the mass of ceramic powder, and secondary ball milling is carried out for 10 h to obtain a ceramic slurry. The polyether acrylate structural unit in the ceramic binder is 20% of the mass of B2O3 in the ceramic slurry; the solid content of the ceramic slurry is 50.3%, the initial slurry viscosity is 1213 cp, and the viscosity after standing for 24 h is 1219 cp.

[0064] 3) Preparation of ceramic sheet:

[0065] The ceramic slurry prepared in the application is cast on a full-automatic casting machine to obtain a ceramic sheet with a thickness of 50 μm.

[0066] Example 2:

[0067] The ceramic binder, ceramic slurry and ceramic sheet are prepared according to the method of Example 1, and the main difference between Example 2 and Example 1 is that in the preparation of the ceramic binder, 5 parts of methacrylic acid, 40 parts of polyethylene glycol monomethyl ether acrylate (Tg2 is -63℃, weight average molecular weight is 1500, and polymerization degree is 30), and 55 parts of tert-butyl methacrylate (Tg1 is 104℃) are selected; the glass transition temperature of the ceramic binder is 18℃, and the weight average molecular weight is 16.8w.

[0068] The remaining operation steps are the same.

[0069] Example 3:

[0070] The ceramic binder, ceramic slurry and ceramic sheet are prepared according to the method of Example 1, and the main difference between Example 3 and Example 1 is that in the preparation of the ceramic binder, 5 parts of acrylamide, 40 parts of polyethylene glycol monomethyl ether acrylate (Tg2 is -68℃, weight average molecular weight is 4000, and polymerization degree is 80), and 55 parts of isobornyl methacrylate (Tg1 is 110℃) are selected; the glass transition temperature of the ceramic binder is 20℃, and the weight average molecular weight is 24.3w.

[0071] The remaining operation steps are the same.

[0072] Example 4:

[0073] The ceramic binder, ceramic slurry and ceramic sheet were prepared according to the method of Example 1, the main difference between Example 4 and Example 1 being that in the preparation of the ceramic binder, 2 parts of methacrylamide, 50 parts of polypropylene glycol monomethyl ether methacrylate (Tg2 of -66°C, weight average molecular weight of 3000, degree of polymerization of 60), 48 parts of isobornyl methacrylate (Tg1 of 110°C) were selected; the glass transition temperature of the ceramic binder was -4°C, and the weight average molecular weight was 26.8w.

[0074] The remaining operation steps were the same.

[0075] Example 5:

[0076] The ceramic binder, ceramic slurry and ceramic sheet were prepared according to the method of Example 1, the main difference between Example 5 and Example 1 being that in the preparation of the ceramic binder, 4 parts of acrylamide, 50 parts of polyethylene glycol monoethyl ether acrylate (Tg2 of -62°C, molecular weight of 1000, degree of polymerization of 20), 26 parts of styrene (Tg1 of 100°C) and 20 parts of acrylonitrile (Tg1' of 125°C) were selected; the glass transition temperature of the ceramic binder was 0°C, and the molecular weight was 28.4w.

[0077] The remaining operation steps were the same.

[0078] Example 6:

[0079] The ceramic binder, ceramic slurry and ceramic sheet were prepared according to the method of Example 1, the main difference between Example 6 and Example 1 being that in the preparation of the ceramic slurry, the ceramic binder (based on the amount of polymer) was 20% of the mass of the ceramic powder, the mass ratio of B2O3:SiO2:Al2O3 in the ceramic powder was 2.5:4.5:3, and the content of B2O3 in the ceramic powder was 25wt%; the polyether acrylate structural unit in the ceramic binder was 32% of the mass of B2O3 in the ceramic slurry; the solid content of the ceramic slurry was 60%.

[0080] The remaining operation steps were the same.

[0081] Example 7:

[0082] The ceramic binder, ceramic slurry and ceramic sheet were prepared according to the method of Example 1, the main difference between Example 7 and Example 1 being that in the preparation of the ceramic slurry, the ceramic binder (based on the amount of polymer) was 8% of the mass of the ceramic powder, the mass ratio of B2O3:SiO2:Al2O3 in the ceramic powder was 2:4.5:3.5, and the content of B2O3 in the ceramic powder was 20wt%; the polyether acrylate structural unit in the ceramic binder was 16% of the mass of B2O3 in the ceramic slurry; the solid content of the ceramic slurry was 45%.

[0083] The remaining operation steps are the same.

[0084] Comparative Example 1:

[0085] Comparative Example 1 differs from Example 1 in that PVB resin is selected as the ceramic binder.

[0086] The remaining operation steps are the same.

[0087] Comparative Example 2:

[0088] Comparative Example 2 differs from Example 1 in that it does not contain polyethylene glycol monomethyl ether acrylate.

[0089] The remaining operation steps are the same.

[0090] Comparative Example 3:

[0091] Comparative Example 3 differs from Example 1 in that it does not contain methyl methacrylate.

[0092] The remaining operation steps are the same.

[0093] Comparative Example 4:

[0094] The ceramic binder, ceramic slurry and ceramic sheet are prepared according to the method of Example 1, and the main difference between Comparative Example 4 and Example 1 is that acrylic acid is replaced by 2-hydroxyethyl acrylate.

[0095] The remaining operation steps are the same.

[0096] Performance test:

[0097] The ceramic binder, ceramic slurry and ceramic sheet prepared in the above examples and comparative examples are subjected to performance testing.

[0098]

Tensile strength

[0099]

Elongation at break

[0100]

Viscosity

[0101] The performance test results are shown in Table 1.

[0102] Table 1:

[0103]

[0104] From the test results of Examples 1-3, 5 and Example 4, it can be seen that when the glass transition temperature of the polymer is 0℃ or higher, the tensile strength of the ceramic sheet is stronger.

[0105] From the test results of Examples 1-3, 6 and Example 7, it can be seen that when the addition amount of the ceramic binder is 10-20% of the mass of the ceramic powder, the tensile strength of the ceramic sheet is stronger.

[0106] From the test results of Examples 1-7 and Comparative Example 1, it can be seen that compared with the traditional PVB resin, the tensile strength of the ceramic binder film of the present application is stronger; the ceramic slurry prepared by the present application is more stable, and the viscosity does not change significantly after standing for 24 h; the tensile strength and flexibility of the ceramic sheet prepared by the present application are significantly improved.

[0107] From the test results of Examples 1-7 and Comparative Examples 2-3, it can be seen that compared with the binder without flexible or hard structural units, the tensile strength of the ceramic binder film of the present application is stronger and the flexibility is better; the tensile strength and flexibility of the ceramic sheet prepared by the present application are significantly improved.

[0108] From the test results of Examples 1-7 and Comparative Example 4, it can be seen that when the polymer contains hydroxyl type structural units, the ceramic slurry will appear thickening phenomenon, and the tensile strength of the ceramic sheet will decrease; but due to the effect of the flexible structural units in the polymer, the thickening phenomenon of the ceramic slurry is improved compared with the PVB binder slurry.

[0109] From the test results of Examples 1-7 and Comparative Example 4, it can be seen that when the polymer does not contain hydroxyl type structural units, it is beneficial to improve the thickening phenomenon of the ceramic slurry and improve the tensile strength of the ceramic sheet; and when the polymer contains the flexible structural units of the present application, even if the polymer contains hydroxyl groups, the thickening phenomenon of the ceramic slurry is also improved compared with the PVB binder slurry.

[0110] The above has further described the present application with the aid of specific examples, but it should be understood that the specific description here should not be understood as limiting the essence and scope of the present application, and various modifications made by those of ordinary skill in the art after reading the above description are within the scope of the present application.

Claims

1. A ceramic binder, characterized by, The ceramic binder is used in a borate glass system with B2O3-SiO2 as the main component, and the ceramic binder comprises a polymer containing a polar structural unit, a hard structural unit and a flexible structural unit. The glass transition temperature Tg1 of the hard structural unit is above 80 DEG C, and the glass transition temperature Tg2 of the flexible structural unit is below 0 DEG C. In the polymer, the mass ratio of the polar structural unit, the flexible structural unit and the hard structural unit is (1-5):(35-65):(35-65). The content of the hydroxyl group in the polymer is less than 0.1 wt%. The polar structural unit comprises any one or a combination of at least two of a carboxylic acid structural unit, an amide structural unit and a sulfonic acid structural unit.

2. The ceramic binder of claim 1, wherein, The polar structural unit comprises any one or a combination of at least two of an acrylic acid structural unit, a methacrylic acid structural unit, an acrylamide structural unit, a methacrylamide structural unit and a 2-acrylamido-2-methylpropane sulfonic acid structural unit.

3. The ceramic binder of claim 1, wherein, The hard structural unit comprises any one or a combination of at least two of an acrylate structural unit, an aromatic vinyl structural unit and a nitrile structural unit.

4. The ceramic binder of claim 1, wherein, The flexible structural unit comprises a polyether acrylate structural unit.

5. The ceramic binder of claim 4, wherein, The weight average molecular weight of the polyether acrylate structural unit is 1000-4000, and / or the glass transition temperature Tg2 of the polyether acrylate structural unit is -10--90 DEG C.

6. The ceramic binder of claim 4 or 5, wherein, The flexible structural unit is selected from one or more of a polyethylene glycol monomethyl ether acrylate structural unit, a polyethylene glycol monoethyl ether acrylate structural unit, a polyethylene glycol monomethyl ether methacrylate structural unit, a polyethylene glycol monoethyl ether methacrylate structural unit and a polypropylene glycol monomethyl ether methacrylate structural unit.

7. The ceramic binder of claim 1, wherein, The glass transition temperature Tg of the polymer is 0-30 DEG C, and / or the weight average molecular weight of the polymer is 15w-30w.

8. A ceramic slurry, characterized by, The ceramic powder comprises a borate glass system with B2O3-SiO2 as the main component.

9. The ceramic slurry of claim 8, wherein, The content of B2O3 in the ceramic powder is 20 wt%-40 wt%, the flexible structural unit of the polymer in the ceramic binder comprises a polyether acrylate structural unit, and the content of the polyether acrylate structural unit is 15%-35% of the content of B2O3.

10. A ceramic sheet, characterized by, The ceramic slurry is prepared by the ceramic slurry of claim 8 or 9.

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