Ceramic slurry and ceramic chip

Abstract

The invention provides ceramic slurry. The ceramic slurry comprises ceramic powder and a ceramic binder, the ceramic powder contains B2O3, and the mass content of the B2O3 in the ceramic powder is 20 wt%-40 wt%; the ceramic binder comprises a polymer, and the polymer contains a polar structural unit, a hard structural unit and a flexible structural unit. The glass transition temperature Tg1 of the hard structural unit is 80 DEG C or more; the glass transition temperature Tg2 of the flexible structural unit is 0 DEG C or less; the polar structural unit comprises a hydroxyl-containing structural unit and simultaneously contains 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; in the ceramic slurry, the content of a hydroxyl-containing structural unit in the polymer is 0.2%-1% of the content of B2O3 in the ceramic powder. The ceramic slurry provided by the invention is stable in viscosity, and a ceramic wafer prepared from the ceramic slurry is high in tensile strength and good in flexibility.

Description

Technical Field

[0001] The present invention belongs to the technical field of low temperature co-fired ceramics, and particularly relates to a ceramic slurry and a ceramic sheet. Background Art

[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: First, the ceramic powder is subjected to ball milling and dispersion treatment, then a plasticizer and a binder are added, and ball milling and mixing are continued. After degassing treatment, a ceramic slurry composition with appropriate viscosity is obtained. Then, tape casting is carried out using equipment such as a doctor blade and a reverse roll coater. After removing volatile components such as solvents by heating and other means, the ceramic sheet is peeled off from the base film. A conductive paste for forming internal electrodes is coated on the obtained ceramic sheet by screen printing process. The coated ceramic sheets are alternately overlapped in multiple layers and heated and pressed to form a laminate. Subsequently, the adhesive resin components and the like in the laminate are subjected to thermal decomposition treatment (i.e., debinding treatment) to remove these components. After that, through a firing process, a ceramic sintered body is obtained, and external electrodes are sintered on its end faces, and finally a multilayer ceramic capacitor is made.

[0004] In the field of LTCC technology, the glass / ceramic composite system is the most widely used system at present. Among them, the borate glass system mainly composed of B2O3-SiO2 has attracted much attention because it can significantly reduce the sintering temperature. However, in the traditional preparation process, polyvinyl butyral resin (abbreviated as PVB) is generally selected as the binder. But when the PVB binder is used in the borate glass system, the stability of the prepared slurry is relatively low, and the key properties such as the tensile strength of the ceramic sheet after tape casting are insufficient.

[0005] Therefore, developing a ceramic binder suitable for tape casting containing borate is of great significance for improving the production efficiency and product quality of LTCC. Summary of the Invention

[0006] In order to solve the problems that when the existing PVB ceramic binder is used in the borate glass system mainly composed of B2O3-SiO2, the stability of the prepared ceramic slurry is low and it is easy to return to thickening, the present invention provides a ceramic slurry and a ceramic sheet.

[0007] The object of the present invention is achieved by the following technical solutions.

[0008] In a first aspect, the present invention provides a ceramic slurry, comprising a ceramic powder and a ceramic binder; the ceramic powder contains B2O3, and the mass content of B2O3 in the ceramic powder is 20 wt% to 40 wt%; the ceramic binder comprises a polymer, and the polymer contains a polar structural unit, a hard structural unit and a flexible structural unit; the glass transition temperature Tg1 of the hard structural unit is 80 °C or higher; the glass transition temperature Tg2 of the flexible structural unit is 0 °C or lower; the polar structural unit comprises a hydroxyl-containing structural unit, and simultaneously contains any one or at least two combinations of a carboxylic acid structural unit, an amide structural unit, and a sulfonic acid structural unit; in the ceramic slurry, the content of the hydroxyl-containing structural unit in the polymer is 0.2% to 1% of the content of B2O3 in the ceramic powder.

[0009] Preferably, in the polymer, the content of the hydroxyl-containing structural unit is 0.5 to 2 wt%.

[0010] Preferably, the hydroxyl-containing structural unit is selected from one or more of a 2-hydroxyethyl acrylate structural unit and a 2-hydroxypropyl acrylate structural unit; the carboxylic acid structural unit is selected from one or more of an acrylic acid structural unit and a methacrylic acid structural unit; the amide structural unit is selected from one or more of an acrylamide structural unit and a methacrylamide structural unit; the sulfonic acid structural unit is selected from a 2-acrylamido-2-methylpropanesulfonic acid structural unit.

[0011] Preferably, the hard structural unit comprises any one or at least two combinations of an acrylate structural unit, an aromatic vinyl structural unit, and a nitrile structural unit.

[0012] Preferably, the flexible structural unit comprises a polyether acrylate structural unit, the weight average molecular weight of the polyether acrylate structural unit is 1000 to 4000, and / or the glass transition temperature Tg2 of the polyether acrylate structural unit is -10 to -90 °C.

[0013] Preferably, the flexible structural unit is selected from one or more of a methoxypolyethylene glycol acrylate structural unit, an ethoxypolyethylene glycol acrylate structural unit, a methoxypolyethylene glycol methacrylate structural unit, an ethoxypolyethylene glycol methacrylate structural unit, and a methoxypolypropylene glycol methacrylate structural unit.

[0014] Preferably, in the polymer, the mass ratio of the polar structural unit, the flexible structural unit to the hard structural unit is (1 to 5):(35 to 65):(35 to 65).

[0015] Preferably, the glass transition temperature Tg of the polymer is 0 to 30 °C; and / or, the weight average molecular weight of the polymer is 150,000 to 300,000.

[0016] Preferably, in the ceramic slurry, the mass of the ceramic binder is 10% to 20% of the mass of the ceramic powder. Preferably, the solid content of the ceramic slurry is 45% to 60%, and the viscosity is 1000 to 8000 cp.

[0017] In a second aspect, the present invention provides a ceramic sheet prepared from the aforementioned ceramic slurry.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] When a traditional PVB binder is used in a borate glass system, the prepared slurry has low stability, is prone to thickening back, which is not conducive to subsequent processing, and there are problems such as insufficient key properties such as the tensile strength of the ceramic sheet after calendaring. Through a large amount of research and analysis, the inventors of the present invention speculate that the reason may be that the large amount of hydroxyl groups in PVB easily interact with B2O3 in the glass powder, resulting in slurry thickening back and performance degradation.

[0020] In the present invention, the content of the hydroxyl group-containing structural unit in the ceramic binder is adjusted to 0.2% to 1% of the content of B2O3 in the ceramic powder, and at the same time, polar structural units such as carboxylic acid structural units, amide structural units, and sulfonic acid structural units are introduced to act together, and then combined with hard structural units and flexible structural units with a specific glass transition temperature, thereby improving the phenomenon of slurry thickening back and, to a certain extent, improving the problems of low tensile strength and toughness of the ceramic sheet. Detailed Embodiments

[0021] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer, the following further describes the present invention in detail in conjunction with specific embodiments. It should be understood that the embodiments described here are part of the embodiments of the present invention, rather than all of the embodiments, and are only used to explain the present invention and not to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0022] In a first aspect, the present invention provides a ceramic slurry, comprising a ceramic powder and a ceramic binder; the ceramic powder contains B2O3, and the mass content of B2O3 in the ceramic powder is 20wt% - 40wt%; the ceramic binder comprises a polymer, and the polymer contains 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°C; the glass transition temperature Tg2 of the flexible structural unit is below 0°C; the polar structural unit comprises a hydroxyl-containing structural unit, and simultaneously contains any one or at least two combinations of a carboxylic acid structural unit, an amide structural unit, and a sulfonic acid structural unit; in the ceramic slurry, the content of the hydroxyl-containing structural unit in the polymer is 0.2% - 1% of the content of B2O3 in the ceramic powder.

[0023] In the present invention, the content of the hydroxyl-containing structural unit in the ceramic binder is adjusted to 0.2% - 1% of the content of B2O3 in the ceramic powder, and at the same time, polar structural units such as carboxylic acid structural units, amide structural units, and sulfonic acid structural units are introduced to act together, and then combined with hard structural units and flexible structural units with specific glass transition temperatures, so as to improve the phenomenon of the ceramic slurry becoming thickened back, and to a certain extent improve the problems of low tensile strength and toughness of the ceramic sheet.

[0024] Preferably, in the polymer, the content of the hydroxyl-containing structural unit is 0.5 - 2wt%.

[0025] According to the present invention, the above-mentioned hydroxyl-containing structural unit can be a structural unit formed in the polymer by free radical polymerization of various hydroxyl-containing monomers commonly used in the art. Preferably, the hydroxyl-containing structural unit is selected from one or more of the structural units of 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate.

[0026] In the present invention, in addition to the hydroxyl-containing structural unit, the polar structural unit in the polymer also contains any one or at least two combinations of a carboxylic acid structural unit, an amide structural unit, and a sulfonic acid structural unit. More preferably, it is any one or at least two combinations of an amide structural unit and a carboxylic acid structural unit.

[0027] At this time, when the content of the hydroxyl-containing structural unit in the polymer is 0.2% - 1% of the content of B2O3 in the ceramic powder, by using a variety of polar structural units in combination, the phenomenon of the ceramic slurry becoming thickened back can be improved to a certain extent, and it is beneficial to improve the tensile strength and elongation at break of the ceramic sheet.

[0028] Specifically, the carboxylic acid structural unit is selected from one or more of an acrylic acid structural unit and a methacrylic acid structural unit. The amide structural unit is selected from one or more of an acrylamide structural unit and a methacrylamide structural unit. The sulfonic acid structural unit is selected from a 2-acrylamido-2-methylpropane sulfonic acid structural unit.

[0029] In the present invention, the glass transition temperature Tg1 of the hard structural unit is 80 °C or higher, 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 tert-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 invention, the glass transition temperature Tg2 of the flexible structural unit is below 0 °C.

[0032] According to the present invention, as a preferred case, the above flexible structural unit includes a polyether acrylate structural unit. Specifically preferred is that 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.

[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 to -90 °C, further preferably -30 to -70 °C.

[0035] 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).

[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 invention, the above-mentioned polar structural unit, hard structural unit, and flexible structural unit are respectively obtained by polymerizing polar monomers, hard monomers, and soft monomers. Among them, the monomers exist in the polymer obtained by polymerization in the form of corresponding structural units. The glass transition temperature, mass ratio, molecular weight, etc. of the above various structural units are based on the glass transition temperature, mutual mass ratio, and molecular weight of their corresponding monomers.

[0038] It should be noted that in the present invention, the content of the above-mentioned polar structural unit is the total content of one or more of the structural units other than the hydroxyl group-containing structural unit and the above other polar structural units. It can be understood that when the hard structural unit contains multiple different structural units, the content range of the above hard structural unit is the total content of all such structural units.

[0039] The above various monomers can be obtained through commercial purchase. For example, for the aforementioned soft monomers, monomers with corresponding parameters can be selected and purchased according to the required molecular weight, degree of polymerization, and Tg2.

[0040] In some specific embodiments, the glass transition temperature Tg of the polymer is 0 to 30 °C.

[0041] Specifically, the glass transition temperature Tg of the polymer can be 0 °C, 5 °C, 10 °C, 14 °C, 18 °C, 20 °C, 25 °C, or 30 °C, etc.

[0042] In some specific embodiments, the weight average molecular weight of the polymer is 150,000 to 300,000.

[0043] Specifically, the weight average molecular weight of the polymer can be 150,000, 200,000, 225,000, 260,000, 280,000, or 300,000, etc.

[0044] In some specific embodiments, the tensile strength of the polymer film prepared is 20 to 40 MPa, and the elongation at break is 50% to 100%.

[0045] The polymer of the present invention can be prepared by a conventional free radical polymerization method. For example, its preparation method can be:

[0046] Mix the polar monomers, soft monomers, and hard monomers in proportion, add an initiator and a solvent, react at 60 to 70 °C for 3 to 5 h, then raise the temperature to 75 to 80 °C and add the initiator again, and continue to react for 5 to 7 h to obtain the polymer of the ceramic binder. Among them, the initiator can be azobisisobutyronitrile, and the addition amount is 0.5 to 2% of the total mass of the monomers. The solvent can be ethyl acetate, and the addition amount is 1.5 to 2 times the total mass of the monomers.

[0047] Preferably, the content of B2O3 in the ceramic powder is 20 wt% to 40 wt%.

[0048] Preferably, in the ceramic slurry, the mass of the ceramic binder is 10-20% of the mass of the ceramic powder.

[0049] In the present invention, in the ceramic slurry, the content of the hydroxy-containing structural unit in the polymer is 0.2%-1% of the content of B2O3 in the ceramic powder. At this time, the phenomenon of slurry thickening can be improved to a certain extent.

[0050] In the ceramic binder, the flexible structural unit of the polymer includes a polyether acrylate structural unit; the content of the polyether acrylate structural unit is 15%-35% of the B2O3 content. At this time, it is very beneficial to further improve the tensile strength and elongation at break of the ceramic sheet.

[0051] Preparation method of the ceramic slurry of the present invention:

[0052] a) Primarily ball-mill the ceramic powder, solvent, and dispersant for 2-4 h. The mass ratio of the raw materials (ceramic powder, solvent, dispersant) to the grinding medium is 1-3:1; the content of B2O3 in the ceramic powder is 20 wt%-40 wt%; the solvent is ethyl acetate, and its addition amount is 75-85% of the mass of the ceramic powder; the dispersant is oleic acid, and its addition amount is 0.5-2% of the mass of the ceramic powder;

[0053] b) Then add the ceramic binder and plasticizer prepared in the present invention. The addition amount of the ceramic binder (based on the amount of the polymer) is 10-20% of the mass of the ceramic powder. The plasticizer is dioctyl phthalate, and its addition amount is 2-4% of the mass of the ceramic powder. Conduct secondary ball-milling for 8-12 h to obtain the ceramic slurry.

[0054] Cast a ceramic sheet from the ceramic slurry prepared in the present invention on a fully automatic casting machine.

[0055] In some specific embodiments, the tensile strength of the ceramic sheet is 6-15 MPa, and the elongation at break is 6%-10%.

[0056] Preferably, the solid content of the ceramic slurry is 45%-60%, and the viscosity is 1000-8000 cp.

[0057] In the second aspect, the present invention provides a ceramic sheet prepared from the aforementioned ceramic slurry.

[0058] The following will further explain the specific embodiments of the present invention through examples and comparative examples.

[0059] Unless otherwise specified, the reagents, materials, and instruments used in the following description are all conventional reagents, conventional materials, and conventional instruments, which are all commercially available. The reagents involved can also be obtained by conventional synthesis methods. The methods in the examples are all conventional methods in the art unless otherwise specified. The monomers conforming to the present invention are commercially available.

[0060] The glass transition temperature can be detected by a differential scanning calorimeter (DSC) in accordance with GB / T 19466.1-2004. The molecular weight of the polymer can be determined by gel permeation chromatography (GPC).

[0061] Example 1:

[0062] 1) Preparation of ceramic binder:

[0063] In a reaction kettle, 4 parts of acrylic acid, 1 part of 2-hydroxyethyl acrylate, 40 parts of methoxypolyethylene glycol acrylate (Tg2 is -65°C, weight average molecular weight is 2000, degree of polymerization is 40), 55 parts of methyl methacrylate (Tg1 is 105°C) are mixed, 0.5 part of azobisisobutyronitrile and 200 parts of ethyl acetate are added, and the reaction is carried out at 65°C for 5 h; the temperature is raised to 80°C, and then 0.5 part of azobisisobutyronitrile is added, and the reaction is continued for 5 h to obtain a ceramic binder containing a polymer. Among them, the glass transition temperature of the polymer is 13°C, and the weight average molecular weight is 16.4 w.

[0064] 2) Preparation of ceramic slurry

[0065] a) In a ball mill tank, the ceramic powder, solvent, and dispersant are initially ball milled for 3 h, and the mass ratio of the raw materials (ceramic powder, solvent, dispersant) to the grinding medium 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 30 wt%; the solvent is ethyl acetate, and its addition amount is 85% of the mass of the ceramic powder; the dispersant is oleic acid, and its addition amount is 1% of the mass of the ceramic powder;

[0066] b) Then, the ceramic binder and plasticizer prepared in the present invention are added to the ball mill tank. The addition amount of the ceramic binder (based on the amount of the polymer) is 15% of the mass of the ceramic powder, and the plasticizer is dioctyl phthalate, and its addition amount is 3% of the mass of the ceramic powder. Secondary ball milling is carried out for 10 h to obtain a ceramic slurry. The content of 2-hydroxyethyl acrylate structural units in the ceramic binder is 0.5% of the mass of B2O3 in the ceramic slurry; the solid content of the ceramic slurry is 58.3%, the initial slurry viscosity is 1231 cp, and the viscosity after standing for 24 h is 1246 cp.

[0067] 3) Preparation of ceramic sheet:

[0068] The ceramic slurry prepared by the present invention is cast on a full-automatic tape casting machine to obtain a ceramic sheet with a thickness of 50 μm.

[0069] Example 2:

[0070] The ceramic binder, ceramic slurry and ceramic sheet are prepared according to the method of Example 1. The main differences between Example 2 and Example 1 are as follows:

[0071] When preparing the ceramic binder, the addition amount of 2-hydroxyethyl acrylate is 2 parts, and the addition amount of acrylic acid is 3 parts;

[0072] In the preparation of the ceramic slurry, the ceramic binder (based on the amount of polymer) is 20% of the mass of the ceramic powder. The mass ratio of B2O3:SiO2:Al2O3 in the ceramic powder is 4:3:3, and the content of B2O3 in the ceramic powder is 40 wt%. The 2-hydroxyethyl acrylate structural unit in the ceramic binder is 1% of the mass of B2O3 in the ceramic slurry. The solid content of the ceramic slurry is 60%.

[0073] The remaining operation steps are the same.

[0074] Example 3:

[0075] The ceramic binder, ceramic slurry and ceramic sheet are prepared according to the method of Example 1. The main differences between Example 3 and Example 1 are as follows:

[0076] When preparing the ceramic binder, the addition amount of 2-hydroxyethyl acrylate is 0.5 part, and the addition amount of acrylic acid is 4.5 parts;

[0077] In the preparation of the ceramic slurry, the ceramic binder (based on the amount of polymer) is 10% of the mass of the ceramic powder. The mass ratio of B2O3:SiO2:Al2O3 in the ceramic powder is 2:4:4, and the content of B2O3 in the ceramic powder is 20 wt%. The 2-hydroxyethyl acrylate structural unit in the ceramic binder is 0.25% of the mass of B2O3 in the ceramic slurry. The solid content of the ceramic slurry is 60%.

[0078] Example 4:

[0079] The ceramic binder, ceramic slurry and ceramic sheet are prepared according to the method of Example 1. The main difference between Example 4 and Example 1 is as follows: In the preparation of the ceramic binder, 4 parts of methacrylic acid, 1 part of 2-hydroxypropyl acrylate, 40 parts of polyethylene glycol monomethyl ether acrylate (Tg2 is -63 °C, weight average molecular weight is 1500, degree of polymerization is 30), and 55 parts of tert-butyl methacrylate (Tg1 is 104 °C) are selected; the glass transition temperature of the ceramic binder is 16 °C, and the weight average molecular weight is 17.3 w.

[0080] The remaining operation steps are the same.

[0081] Example 5:

[0082] Prepare the ceramic binder, ceramic slurry and ceramic sheet according to the method of Example 1. The main difference between Example 5 and Example 1 is that in the preparation of the ceramic binder, 4 parts of acrylamide, 1 part of 2-hydroxypropyl acrylate, 40 parts of methoxypolyethylene glycol acrylate (Tg2 is -68 °C, weight-average molecular weight is 4000, degree of polymerization is 80), and 55 parts of isobornyl methacrylate (Tg1 is 110 °C) are selected; the glass transition temperature of the ceramic binder is 18 °C, and the weight-average molecular weight is 252,000.

[0083] The remaining operation steps are the same.

[0084] Example 6:

[0085] Prepare the ceramic binder, ceramic slurry and ceramic sheet according to the method of Example 1. The main difference between Example 6 and Example 1 is that in the preparation of the ceramic binder, 1 part of methacrylamide, 1 part of 2-hydroxypropyl acrylate, 50 parts of methoxypolypropylene glycol methacrylate (Tg2 is -66 °C, weight-average molecular weight is 3000, degree of polymerization is 60), and 48 parts of isobornyl methacrylate (Tg1 is 110 °C) are selected; the glass transition temperature of the ceramic binder is -5 °C, and the weight-average molecular weight is 273,000.

[0086] The remaining operation steps are the same.

[0087] Example 7:

[0088] Prepare the ceramic binder, ceramic slurry and ceramic sheet according to the method of Example 1. The main difference between Example 7 and Example 1 is that in the preparation of the ceramic binder, 3 parts of acrylamide, 1 part of 2-hydroxypropyl acrylate, 50 parts of ethoxypolyethylene glycol acrylate (Tg2 is -62 °C, molecular weight is 1000, degree of polymerization is 20), 26 parts of styrene (Tg1 is 100 °C) and 20 parts of acrylonitrile (Tg1' is 125 °C) are selected; the glass transition temperature of the ceramic binder is -1 °C, and the molecular weight is 293,000.

[0089] The remaining operation steps are the same.

[0090] Example 8:

[0091] The difference between Example 8 and Example 1 is that isooctyl acrylate with a glass transition temperature Tg of -70 °C is used to replace methoxypolyethylene glycol acrylate in Example 1.

[0092] The remaining operation steps are the same.

[0093] Comparative Example 1:

[0094] The difference between Comparative Example 1 and Example 1 is that PVB resin is selected as the ceramic binder.

[0095] The remaining operation steps are the same.

[0096] Comparative Example 2:

[0097] The difference between Comparative Example 2 and Example 1 is that it does not contain acrylic acid, and the addition amount of 2-hydroxyethyl acrylate is 5 parts.

[0098] The remaining operation steps are the same.

[0099] Performance test:

[0100] Perform performance tests on the ceramic binders, ceramic slurries and ceramic wafers prepared in the above examples and comparative examples.

[0101]

Tensile strength

[0102]

Elongation at break

[0103]

Viscosity

[0104] The performance test results are shown in Table 1.

[0105] Table 1:

[0106] It can be seen from the test results of Examples 1 to 8 and Comparative Example 1 that compared with the traditional PVB resin, the ceramic slurry prepared by the ceramic binder of the present invention is more stable, the phenomenon of thickening back is improved, and the tensile strength and flexibility of the prepared ceramic wafers are significantly improved.

[0107] It can be seen from the test results of Examples 1 to 8 and Comparative Example 2 that compared with the binder with only hydroxyl-containing structural units in the polar structural unit, the ceramic slurry prepared by the ceramic binder of the present invention is more stable, the phenomenon of thickening back is improved, and the tensile strength of the prepared ceramic wafers is significantly improved.

[0108] The above further describes the present invention by means of specific embodiments. However, it should be understood that this specific description should not be construed as a limitation on the essence and scope of the present invention. Various modifications made by those of ordinary skill in the art to the above embodiments after reading this specification all fall within the scope protected by the present invention.

Claims

1. A ceramic slurry, characterized in that: The ceramic slurry includes ceramic powder and ceramic binder; The ceramic powder contains B2O3, and the mass content of B2O3 in the ceramic powder is 20wt%~40wt%; The ceramic binder includes a polymer, and the polymer contains 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° C.; the glass transition temperature Tg2 of the flexible structural unit is below 0° C.; The polar structural unit includes a hydroxyl-containing structural unit and contains 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; In the ceramic slurry, the content of the hydroxyl-containing structural unit in the polymer is 0.2% to 1% of the content of B2O3 in the ceramic powder.

2. The ceramic slurry according to claim 1, characterized in that In the polymer, the content of the hydroxyl-containing structural unit is 0.5-2wt%.

3. The ceramic slurry according to claim 1, characterized in that The hydroxyl-containing structural unit is selected from one or more of 2-hydroxyethyl acrylate structural units and 2-hydroxypropyl acrylate structural units; the carboxylic acid structural unit is selected from one or more of acrylic acid structural units and methacrylic acid structural units; the amide structural unit is selected from one or more of acrylamide structural units and methacrylamide structural units; the sulfonic acid structural unit is selected from 2-acrylamide-2-methylpropanesulfonic acid structural units.

4. The ceramic slurry according to claim 1, characterized in that The hard structural unit includes any one of an acrylic ester structural unit, an aromatic vinyl structural unit, and a nitrile structural unit, or a combination of at least two of them.

5. The ceramic slurry according to claim 1, characterized in that: The flexible structural unit comprises a polyether acrylate structural unit, 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°C.

6. The ceramic slurry according to claim 5, characterized in that The flexible structural unit is 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.

7. The ceramic slurry according to claim 1, characterized in that 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).

8. The ceramic slurry according to claim 1, characterized in that: The glass transition temperature Tg of the polymer is 0-30° C.; and / or the weight average molecular weight of the polymer is 15w-30w.

9. The ceramic slurry according to claim 1, characterized in that: In the ceramic slurry, the mass of the ceramic binder is 10-20% of the mass of the ceramic powder.

10. A ceramic sheet, characterized in that: Prepared from the ceramic slurry described in any one of claims 1 to 9.

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