Powder materials, powder material pastes and fired films

Abstract

To provide a powder material that prevents chipping of an overcoat layer and residues of a resistor when trimming the resistor having the overcoat layer thereon with near-infrared radiation laser.SOLUTION: A powder material contains lead-based glass powder of 80-99.5 mass%, inorganic pigment of 0.5-12 mass%, and inorganic filler of 0-8 mass%, with the inorganic pigment being black pigment and / or green pigment.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a powder material, a powder material paste, and a fired film, and more particularly to a powder material, a powder material paste, and a fired film for forming an overcoat layer on a resistor or the like. [Background technology]

[0002] An overcoat layer is formed to protect and insulate resistors and other components formed on a soda-lime glass substrate, an alumina substrate, or the like. Conventionally, a powder material paste has been used to form the overcoat layer. This powder material paste is generally a mixture of glass powder and a vehicle, and ceramic powder may be added as needed.

[0003] The overcoat layer is formed by applying a powder material paste to a resistor or the like, followed by firing. The firing temperature is limited to 620°C or less to prevent the resistor or the like from reacting with the powder material, which could degrade the characteristics of the resistor or the like. For this reason, the powder material (powder material paste) is required to be able to be fired at a temperature of 620°C or less, and lead-based glass with a low softening point is generally used (see Patent Document 1).

[0004] In addition, in order to adjust the resistance value of the resistor with the overcoat layer formed within a certain range, it is necessary to trim part of the resistor by irradiating it from above the overcoat layer with a near-infrared laser (wavelength: 1064 nm) such as Nd:YAG or Nd:YVO4. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 58-64245 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when a resistor having an overcoat layer made of lead-based glass as described in Patent Document 1 is trimmed using a near-infrared laser, problems arise, such as chipping of the overcoat layer and residues being left on the resistor.

[0007] An object of the present invention is to provide a powder material that is less likely to cause chipping of the overcoat layer or residue of the resistor when a resistor having an overcoat layer formed thereon is trimmed using a near-infrared laser. [Means for solving the problem]

[0008] The powder material of the present invention is characterized in that the content of lead-based glass powder is 80 to 99.5 mass %, the content of inorganic pigment is 0.5 to 12 mass %, the content of inorganic filler is 0 to 8 mass %, and the inorganic pigment is a black pigment and / or a green pigment. "Lead-based glass powder" is glass powder containing 30 mass % or more of PbO.

[0009] By controlling the content of the lead-based glass powder, inorganic pigment, and inorganic filler as described above, the diffuse transmittance and diffuse absorptance of the overcoat layer can be controlled to desired values, resulting in less chipping of the overcoat layer and less residue of the resistor. If the diffuse transmittance is too low and / or the diffuse absorptance is too high, the laser has difficulty reaching the resistor, making it more likely to leave residue of the resistor. If the diffuse absorptance is too low, the temperature of the overcoat layer is less likely to rise, making it more likely to chip.

[0010] In the powder material of the present invention, the inorganic pigment is preferably substantially free of Cr2O3. "Substantially free of Cr2O3" means that the Cr2O3 content in the pigment is less than 0.1% by mass.

[0011] In the powder material of the present invention, the lead-based glass powder preferably contains, by mass %, 30 to 80% PbO, 0 to 20% B2O3, 10 to 50% SiO2, 0 to 10% Al2O3, and 0 to 10% ZnO.

[0012] In the powder material of the present invention, the black pigment is preferably an Fe—Mn composite oxide.

[0013] In the powder material of the present invention, the green pigment is preferably a Co—Ni—Ti composite oxide.

[0014] The powder material of the present invention is preferably used to form an overcoat layer.

[0015] The powder material paste of the present invention is characterized by containing the above powder material and a vehicle.

[0016] The fired film of the present invention is a fired film obtained by firing the above powder material paste, and is characterized by having a diffuse transmittance of 45% or more and a diffuse absorptance of 8 to 40% at a wavelength of 1064 nm when converted to a thickness of 10 μm. [Effects of the Invention]

[0017] To provide a powder material that is less likely to cause chipping of the overcoat layer and residue of the resistor when a resistor on which an overcoat layer is formed is trimmed using a near-infrared laser. DETAILED DESCRIPTION OF THE INVENTION

[0018] The powder material of the present invention has a lead-based glass powder content of 80 to 99.5 mass%, preferably 82 to 99 mass%, and particularly preferably 84 to 98.5 mass%, an inorganic pigment content of 0.5 to 12 mass%, preferably 0.7 to 11.5 mass%, and particularly preferably 1 to 11 mass%, and an inorganic filler content of 0 to 8 mass%, preferably 0.1 to 7.5 mass%, and particularly preferably 0.5 to 7 mass%. If the lead-based glass powder content is too low, sinterability is likely to deteriorate. As a result, the diffuse transmittance of the overcoat layer is likely to decrease and resistor residue is likely to occur. On the other hand, if the lead-based glass powder content is too high, the inorganic pigment content will be relatively low, which will likely decrease the diffuse absorptance of the overcoat layer and cause chipping of the overcoat layer. If the inorganic pigment content is too low, the diffuse absorptance of the overcoat layer will likely decrease and cause chipping of the overcoat layer. On the other hand, if the content of the inorganic pigment is too high, the diffuse transmittance of the overcoat layer tends to decrease, and the resistor residue tends to be generated.If the content of the inorganic filler is too high, the diffuse transmittance of the overcoat layer tends to decrease, and the resistor residue tends to be generated.

[0019] Next, the lead-based glass powder will be described.

[0020] (Lead-based glass powder) The lead-based glass powder preferably contains, by mass%, 30-80% PbO, 0-20% BO, 10-50% SiO, 0-10% AlO, and 0-10% ZnO. The reasons for restricting the content range of each component as described above are explained below. In the explanation of the content range of each component, % means % by mass.

[0021] PbO is a component that lowers the softening point and also enhances acid resistance. The PbO content is preferably 30 to 80%, 40 to 75%, 45 to 70%, and particularly preferably 50 to 65%. If the PbO content is too low, the softening point will rise unduly, making it difficult to sinter at temperatures below 620°C. Also, acid resistance will tend to decrease. On the other hand, if the PbO content is too high, metallic lead will tend to precipitate during sintering.

[0022] B2O3 is a component that forms a glass skeleton and further expands the vitrification range. The B2O3 content is preferably 0 to 20%, 1 to 18%, 2 to 16%, and particularly preferably 3 to 14%. If the B2O3 content is too high, acid resistance tends to decrease.

[0023] SiO2 is a component that forms the glass skeleton and also enhances acid resistance. The SiO2 content is preferably 10 to 50%, 15 to 45%, 17 to 40%, and particularly preferably 20 to 30%. If the SiO2 content is too low, acid resistance tends to decrease. On the other hand, if the SiO2 content is too high, the softening point increases unduly, making it difficult to fire at temperatures below 620°C.

[0024] Al2O3 is a component that forms the glass skeleton and also enhances acid resistance. The Al2O3 content is preferably 0 to 10%, 0 to 8%, 0 to 6%, and particularly preferably 0.1 to 5%. If the Al2O3 content is too high, the softening point will increase unduly, making it difficult to fire at temperatures below 620°C.

[0025] ZnO is a component that lowers the softening point but also reduces acid resistance. The ZnO content is preferably 0 to 10%, 0 to 5%, 0 to 4%, and particularly preferably 0.1 to 3%. If the ZnO content is too high, acid resistance tends to decrease.

[0026] In addition to the above components, the following components may be incorporated:

[0027] MgO is a component that stabilizes glass. The content of MgO is preferably 0 to 5%, 0 to 4%, and particularly preferably 0 to 3%. If the content of MgO is too high, acid resistance tends to decrease.

[0028] CaO is a component that lowers the softening point and stabilizes the glass. The CaO content is preferably 0 to 5%, 0 to 4%, and particularly preferably 0 to 3%. If the CaO content is too high, the acid resistance tends to decrease.

[0029] SrO is a component that lowers the softening point and stabilizes the glass. The SrO content is preferably 0 to 5%, 0 to 4%, and particularly preferably 0 to 3%. If the SrO content is too high, the acid resistance tends to decrease.

[0030] BaO is a component that lowers the softening point and stabilizes the glass. The BaO content is preferably 0 to 5%, 0 to 4%, and particularly preferably 0 to 3%. If the BaO content is too high, the acid resistance tends to decrease.

[0031] TiO2 is a component that enhances acid resistance. The TiO2 content is preferably 0 to 10%, 0 to 5%, 0 to 4%, and particularly preferably 0.1 to 3%. If the TiO2 content is too high, crystallization occurs easily, and the density of the overcoat layer tends to deteriorate.

[0032] The softening point of the lead-based glass powder is preferably 500 to 610°C, 520 to 605°C, or 540 to 600°C. If the softening point is too low, the resistor, etc. and the powder material are likely to react during firing, which can lead to deterioration of the resistor, etc. characteristics. On the other hand, if the softening point is too high, the firing temperature must be increased to obtain a dense overcoat layer, which can lead to reaction between the resistor, etc. and the powder material, which can lead to deterioration of the resistor, etc. characteristics. Here, the "softening point" refers to the value of the fourth inflection point measured with a macro-type differential thermal analyzer (DTA).

[0033] Average particle size D of lead-based glass powder 50 is preferably 3 μm or less, and the maximum particle size D max The average particle size D is preferably 20 μm or less. If the particle size of the lead-based glass powder is too large, the surface smoothness of the fired film tends to deteriorate. 50 " refers to the value measured by a laser diffraction device, and represents the particle size at which the cumulative amount accumulates to 50% from the smallest particle size on the volume-based cumulative particle size distribution curve measured by the laser diffraction method. max" refers to a value measured using a laser diffraction device, and represents the particle size at which the cumulative amount, starting from the smallest particle, accounts for 99% of the total volume on a cumulative particle size distribution curve measured using a laser diffraction method.

[0034] Next, inorganic pigments will be described.

[0035] (inorganic pigments) In consideration of the environment, it is preferable that the inorganic pigment does not substantially contain Cr2O3. 50 It is preferable to use one having a particle size of about 0.2 to 5 μm.

[0036] The inorganic pigment is a black pigment and / or a green pigment, and is preferably an Fe-Mn composite oxide such as an Fe-Mn-Cu-Co composite oxide, or a Co-Ni-Ti composite oxide such as a Co-Ni-Ti-Zn composite oxide or a Co-Ni-Ti-Al composite oxide. The black pigment is preferably an Fe-Mn composite oxide such as an Fe-Mn-Cu composite oxide or an Fe-Mn-Cu-Co composite oxide, and the green pigment is preferably a Co-Ni-Ti composite oxide such as a Co-Ni-Ti-Zn composite oxide or a Co-Ni-Ti-Al composite oxide.

[0037] Next, the inorganic filler will be described.

[0038] (inorganic filler) As the inorganic filler, powders of cordierite, willemite, β-eucryptite, mullite, zircon, lead titanate, etc. can be used to adjust the expansion coefficient, etc. The particle size of the inorganic filler is the average particle size D 50 It is preferable to use one having a particle size of about 0.2 to 5 μm.

[0039] Next, the powder material, the powder material paste, and the method for producing the fired film of the present invention will be described.

[0040] First, molten glass is formed into a film, and the resulting glass film is crushed and classified to produce a lead-based glass powder. The lead-based glass powder, inorganic pigment, and inorganic filler are then mixed in a predetermined ratio to obtain a powder material.

[0041] The powder material and the vehicle are then mixed and kneaded in a predetermined ratio to produce a powder material paste. The vehicle may contain, for example, an organic solvent, a resin, a plasticizer, a dispersant, etc.

[0042] The organic solvent is a material for forming a paste from the glass powder, and examples thereof include terpineol (Ter), diethylene glycol monobutyl ether (BC), diethylene glycol monobutyl ether acetate (BCA), 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, dihydroterpineol, etc., which can be used alone or in combination. The content of the organic solvent is preferably 10 to 40 mass %.

[0043] The resin is a component that increases the strength of the film after drying and imparts flexibility, and its content is generally about 0.1 to 20 mass %. The resin is a thermoplastic resin, specifically, polybutyl methacrylate, polyvinyl butyral, polymethyl methacrylate, polyethyl methacrylate, ethyl cellulose, etc., which can be used alone or in combination.

[0044] The plasticizer is a component that controls the drying speed and gives flexibility to the dried film, and its content is generally about 0 to 10% by mass. Examples of plasticizers that can be used include butyl benzyl phthalate, dioctyl phthalate, diisooctyl phthalate, dicapryl phthalate, and dibutyl phthalate, and these can be used alone or in combination.

[0045] As the dispersant, ionic or nonionic dispersants can be used, and ionic dispersants include polycarboxylic acid dispersants such as carboxylic acids and dicarboxylic acids, and amine dispersants, while nonionic dispersants include polyester condensation dispersants and polyhydric alcohol ether dispersants. The amount used is generally 0 to 5% by mass.

[0046] Next, the powder material paste is applied to the resistor by screen printing, batch coating, or the like to form an overcoat layer of a predetermined thickness, which is then dried to obtain a dry film. The dried film is then fired at a temperature of 500 to 620°C for 5 to 20 minutes to form the desired overcoat layer (fired film). If the firing temperature is too low or the firing time (holding time) is too short, the dried film will not be sufficiently sintered, making it difficult to form a dense fired film. On the other hand, if the firing temperature is too high or the holding time is too long, the powder material will react with the resistor, etc., which can easily deteriorate the characteristics of the resistor, etc.

[0047] The fired film preferably has a diffuse transmittance of 45% or more, 47% or more, 50% or more, or 52% or more, particularly 54% or more at a wavelength of 1064 nm, calculated as a thickness of 10 μm, and a diffuse absorptance of 8 to 40%, 9 to 38%, particularly 10 to 36%. If the diffuse transmittance is too low and / or the diffuse absorptance is too high, it becomes difficult for the laser to reach the resistor, and resistor residue is likely to be generated. If the diffuse absorptance is too low, it becomes difficult for the overcoat layer to increase in temperature, and chipping of the overcoat layer is likely to occur.

[0048] Although the method of using a powder material paste has been described as an example of the method of forming the overcoat layer (fired film), other methods may also be used, such as the green sheet method, the photosensitive paste method, and the photosensitive green sheet method. [Example]

[0049] The present invention will be described in detail below based on examples. However, the present invention is not limited to the following examples. The following examples are merely illustrative.

[0050] Table 1 shows examples of lead-based glass powders (samples A, B, and C), and Table 2 shows examples of the present invention (samples Nos. 1 to 4) and comparative examples (samples Nos. 5 and 6).

[0051] [Table 1]

[0052] [Table 2]

[0053] (Preparation of lead-based glass powder) First, the raw materials were prepared and mixed uniformly to obtain the glass composition shown in Table 1. Then, the mixture was placed in a platinum crucible and melted at 1150 to 1350°C for 2 hours, and then formed into a film. The obtained glass film was pulverized in a ball mill and then air-classified to determine the average particle size D 50 3.0μm or less, maximum particle size D max A lead-based glass powder having a particle size of 20 μm or less was obtained.The softening point of the obtained lead-based glass powder was evaluated.

[0054] The softening point was the value of the fourth inflection point measured by a macro-type differential thermal analyzer (DTA).

[0055] (Preparation of powder materials) Next, lead-based glass powder, inorganic pigment, and inorganic filler were mixed in the proportions shown in Table 2 to prepare a powder material.

[0056] Next, the powder material and vehicle (terpineol containing 5% by mass of polybutyl methacrylate and 3% by mass of dibutyl phthalate) were mixed and kneaded in a three-roll mill to obtain a powder material paste. The powder material paste was then applied to a resistor (RuO2) by screen printing to obtain a fired film (overcoat layer) of approximately 10 μm. The applied film was then dried and fired in an electric furnace at 620°C for 10 minutes to form a fired film. A portion of the resistor with the fired film was trimmed by irradiating the resistor with a Nd:YAG near-infrared laser (wavelength: 1064 nm) from above the fired film, and the resistor residue and chipping of the fired film were confirmed. The diffuse transmittance and diffuse reflectance of the fired film were also measured using a spectrophotometer.

[0057] The residue of the resistor was evaluated as "good" when no residue of the resistor was visually observed, and as "poor" when residue of the resistor was visually observed.

[0058] The chipping of the fired film was evaluated as "good" when no chipping of the fired film was visually confirmed, and as "poor" when chipping of the fired film was confirmed.

[0059] As is clear from the table, no resistor residue or chipping of the fired film was observed in samples Nos. 1 to 4. On the other hand, resistor residue was observed in sample No. 5. Chip- ping of the fired film was observed in sample No. 6. [Industrial Applicability]

[0060] The powder material, powder material paste, and fired film of the present invention are particularly suitable for overcoat layers, particularly overcoat layers for chip resistors, but can also be used for other purposes, such as binders for electronic component materials and sealing materials.

Claims

1. The content of the lead-based glass powder is 80 to 99.5% by mass, the content of the inorganic pigment is 0.5 to 12% by mass, and the content of the inorganic filler is 0 to 8% by mass, The lead-based glass powder contains, in mass %, 30 to 80% PbO, B ２ O ３ 0-3%, SiO ２ 20-30%, Al ２ O ３ 0 to 1% of SnO, 0.1 to 2% of ZnO, the inorganic pigment is a black pigment and / or a green pigment, A powder material characterized in that the green pigment is a Co-Ni-Ti based composite oxide.

2. The inorganic pigment is substantially Cr ２ O ３ 2. The powder material according to claim 1, wherein the powder material does not contain:

3. 3. The powder material according to claim 1, wherein the black pigment is an Fe-Mn based composite oxide.

4. 4. The powder material according to claim 1, which is used to form an overcoat layer.

5. A powder material paste comprising the powder material according to any one of claims 1 to 4 and a vehicle.

6. A fired film obtained by sintering the powder material paste according to claim 5, characterized in that the film has a diffuse transmittance of 45% or more at a wavelength of 1064 nm and a diffuse absorption rate of 8 to 40% at a thickness of 10 μm.

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