JP6315403B2 - Powder material and powder material paste - Google Patents

Description

  The present invention relates to a glass composition, a powder material, and a powder material paste. For example, the present invention relates to a glass composition, a powder material, and a powder material paste for forming an overcoat layer on an electronic circuit or the like.

  The overcoat layer is formed to protect and insulate electrodes, resistors, and the like formed on a soda lime glass substrate, an alumina substrate, and the like. Conventionally, a powder material paste has been used to form an overcoat layer. This powder material paste is generally a mixture of glass powder and vehicle, and ceramic powder may be added as necessary.

  The overcoat layer is formed by applying a powder material paste to an electrode or the like and then baking it. Here, the firing temperature is limited to 840 ° C. or lower in order to prevent a situation where the electrode material and the powder material react to deteriorate the properties of the electrode. For this reason, the powder material (powder material paste) is required to be able to be fired at a temperature of 840 ° C. or lower. The powder material is also required not to easily peel off from the substrate after firing.

Conventionally, PbO—B ₂ O ₃ —SiO ₂ -based glass has been used as a powder material that satisfies the above required characteristics (see Patent Document 1).

In recent years, from the viewpoint of environmental protection, reduction of environmentally hazardous substances, for example, reduction of PbO has been promoted, and various lead-free glasses have been proposed in place of PbO—B ₂ O ₃ —SiO ₂ based glass. Yes. For example, Patent Document 2 discloses Bi ₂ O ₃ —ZnO—B ₂ O ₃ -based glass, and Patent Document 3 discloses SiO ₂ —B ₂ O ₃ —ZnO-based glass.

JP 58-64245 A JP 2002-60064 A JP-A-2005-314201

  By the way, the electronic circuit in which the overcoat layer is formed may be subjected to a plating treatment in order to impart characteristics such as anticorrosion, optical characteristics, mechanical characteristics, and electrical characteristics. In this plating process, the overcoat layer is immersed in a plating solution.

  The plating solution is usually an acidic solution. For this reason, when a plating process is performed, the overcoat layer is required to have acid resistance. That is, acid resistance is required for the powder material. Since the lead glass described in Patent Document 1 contains a large amount of PbO in the glass composition, it has good acid resistance.

  However, since the lead-free glass described in Patent Documents 2 and 3 has low acid resistance, it has a problem that it is easily eroded by the plating solution and it is difficult to maintain characteristics such as insulation.

  Therefore, the present invention has been made in view of the above circumstances, and the technical problem thereof is that the glass composition can be baked at a temperature of 840 ° C. or less and does not warp the substrate without containing a large amount of PbO. And a glass composition, a powder material, and a powder material paste that do not easily peel off from a substrate and are not easily eroded by a plating solution.

As a result of various experiments, the present inventor adopted SiO ₂ —B ₂ O ₃ —ZrO ₂ -based glass as a glass system and a molar ratio (SiO ₂ + ZrO ₂ ) / (B ₂ O in the glass composition). It has been found that the above technical problem can be solved by regulating ( ₃ + ZnO) to a predetermined value or more, and is proposed as the present invention. That is, the glass composition of the present invention has a glass composition, in _{mol%, SiO 2 50~70%, B} 2 O 3 4 super _{~15%, ZrO 2 5~15%,} 1~10% ZnO, MgO + CaO + SrO + BaO 0 0.5 to 20%, Li ₂ O + Na ₂ O + K ₂ O 0.5 to 15%, Al ₂ O ₃ 0 to 10%, and a molar ratio (SiO ₂ + ZrO ₂ ) / (B ₂ O ₃ + ZnO) is 2 Greater than .8. Here, “MgO + CaO + SrO + BaO” is the total amount of MgO, CaO, SrO and BaO. “Li ₂ O + Na ₂ O + K ₂ O” is the total amount of Li ₂ O, Na ₂ O and K ₂ O. “SiO ₂ + ZrO ₂ ” is the total amount of SiO ₂ and ZrO ₂ . “B ₂ O ₃ + ZnO” is the total amount of B ₂ O ₃ and ZnO.

The glass composition of the present invention regulates the content of SiO ₂ to 50 mol% or more, the content of ZrO ₂ to 5 mol% or more, the content of B ₂ O ₃ to 15 mol% or less, and ZnO Is controlled to be 10 mol% or less, and the molar ratio (SiO ₂ + ZrO ₂ ) / (B ₂ O ₃ + ZnO) is further controlled to exceed 2.8. Thereby, even if it does not contain a large amount of PbO in a glass composition, desired acid resistance can be ensured.

  In the glass composition of the present invention, the content of MgO is 5 mol% or less, the content of CaO is 20 mol% or less, the content of SrO is 15 mol% or less, and the content of BaO is 15 mol% or less. It is preferable.

The glass composition of the present invention preferably has a Li ₂ O content of 2 mol% or less, a Na ₂ O content of 10 mol% or less, and a K ₂ O content of 10 mol% or less.

  It is preferable that the glass composition of the present invention does not substantially contain PbO. Here, “substantially free of PbO” means that PbO is allowed to be mixed in at an impurity level, but avoids aggressive introduction. Specifically, the content of PbO in the glass composition Is less than 1000 ppm (less than 0.1 mol%).

  The powder material of the present invention is a powder material containing glass powder and ceramic powder made of the above glass composition, wherein the glass powder content is 50 to 100% by mass and the ceramic powder content is 0 to 50. It is preferable that it is mass%. The powder material of the present invention includes not only the case of containing ceramic powder but also the case of being composed of only glass powder without containing ceramic powder.

  The powder material of the present invention preferably has a softening point of 840 ° C. or lower. Here, the “softening point” refers to the value of the fourth inflection point measured with a macro-type differential thermal analyzer (DTA).

  The powder material of the present invention is preferably used for forming an overcoat layer.

  The powder material paste of the present invention is preferably a powder material paste containing the powder material and a vehicle.

  The powder material paste of the present invention preferably contains substantially no phthalic acid compound. Here, “substantially no phthalic acid compound” refers to the case where the content of the phthalic acid compound in the powder material paste is less than 1000 ppm (less than 0.1% by mass).

The glass composition of the present invention has a glass composition of mol%, SiO ₂ 50 to 70%, B ₂ O _{3 over} 4 to 15%, ZrO ₂ 5 to 15%, ZnO 1 to 10%, MgO + CaO + SrO + BaO 0.5 _{~20%, Li 2 O + Na} 2 O + K 2 O 0.5~15%, containing _Al 2 O 3 _0~10%, molar ratio _{(SiO 2 + ZrO 2) /} (B 2 O 3 + ZnO) 2.8 It is characterized by being larger. The reason why the content range of each component is regulated as described above will be described below. In addition, in description of the containing range of each component,% display means mol%.

SiO ₂ is a component that forms a glass skeleton and a component that increases acid resistance. The content of SiO ₂ is 50 to 70%, preferably 55 to 65%, more preferably 56 to 64%, and particularly preferably 57 to 63%. When the content of SiO ₂ is reduced, the acid resistance is lowered, and the overcoat layer is easily eroded by the plating solution, and as a result, it is difficult to ensure the protection and insulation of the electrodes of the electronic circuit. On the other hand, when the content of SiO ₂ is increased, the softening point is unduly increased, and it becomes difficult to fire at a temperature of 840 ° C. or lower.

B ₂ O ₃ is a component that forms a glass skeleton and widens the vitrification range. However, when the content of B ₂ O ₃ increases, the acid resistance is greatly reduced, and the overcoat layer is easily eroded by the plating solution. As a result, it becomes difficult to secure protection and insulation of the electrodes of the electronic circuit. Therefore, the content of B ₂ O ₃ is more than 4 to 15%, preferably 5 to 13%, particularly preferably 6 to 11%.
ZrO ₂ is a component that increases acid resistance. The content of ZrO ₂ is 5 to 15%, preferably 6 to 13%, particularly preferably 7 to 11%. When the content of ZrO ₂ decreases, the acid resistance decreases and the overcoat layer is easily eroded by the plating solution, and as a result, it becomes difficult to ensure protection and insulation of the electrodes of the electronic circuit. On the other hand, when the content of ZrO ₂ is increased, the solubility and meltability are lowered, the softening point is unduly increased, and it becomes difficult to fire at a temperature of 840 ° C. or lower.

  ZnO is a component that lowers the softening point, but is a component that reduces acid resistance. The content of ZnO is 1 to 10%, preferably 2 to 9%, more preferably 2.5 to 7%, and particularly preferably 3 to 6%. When the content of ZnO is reduced, the softening point is unreasonably raised and it becomes difficult to fire at a temperature of 840 ° C. or lower. On the other hand, when the content of ZnO is increased, the acid resistance is significantly lowered, and the overcoat layer is easily eroded by the plating solution, and as a result, it is difficult to ensure protection and insulation of the electrodes of the electronic circuit.

  The content of MgO + CaO + SrO + BaO is 0.5 to 20%, preferably 1 to 17%, more preferably 2 to 14%, and particularly preferably 3 to 12%. When the content of MgO + CaO + SrO + BaO decreases, it becomes difficult to stabilize the glass. On the other hand, when the content of MgO + CaO + SrO + BaO increases, the acid resistance decreases, and the overcoat layer is easily eroded by the plating solution, and as a result, it becomes difficult to ensure protection and insulation of the electrodes of the electronic circuit.

  MgO is a component that lowers the softening point and is a component that stabilizes the glass. The content of MgO is preferably 0 to 5%, more preferably 0 to 4%, and particularly preferably 0 to 3%. When the content of MgO increases, the acid resistance decreases and the overcoat layer is easily eroded by the plating solution, and as a result, it becomes difficult to ensure the protection and insulation of the electrodes of the electronic circuit.

  CaO is a component that lowers the softening point and is a component that stabilizes the glass. The content of CaO is preferably 0 to 20%, preferably 1 to 18%, more preferably 1.5 to 14%, and particularly preferably 2 to 10%. When the content of CaO increases, the acid resistance decreases and the overcoat layer is easily eroded by the plating solution, and as a result, it becomes difficult to ensure protection and insulation of the electrodes of the electronic circuit.

  SrO is a component that lowers the softening point and is a component that stabilizes the glass. The SrO content is preferably 0 to 15%, more preferably 0.5 to 14%, and particularly preferably 1 to 13%. When the SrO content is increased, the acid resistance is lowered, and the overcoat layer is easily eroded by the plating solution. As a result, it is difficult to ensure protection and insulation of the electrodes of the electronic circuit.

  BaO is a component that lowers the softening point and is a component that stabilizes the glass. The content of BaO is preferably 0 to 15%, more preferably 0.5 to 14%, and particularly preferably 1 to 13%. When the content of BaO increases, the acid resistance decreases, and the overcoat layer is easily eroded by the plating solution, and as a result, it becomes difficult to ensure the protection and insulation of the electrodes of the electronic circuit.

_{Li 2 O + Na 2 O +} K 2 O is from 0.5 to 15%, preferably 1-13%, more preferably 2-12%, more preferably 3-10%, particularly preferably 5-9%. When the content of Li ₂ O + Na ₂ O + K ₂ O is decreased, the softening point is unreasonably increased and it becomes difficult to fire at a temperature of 840 ° C. or lower. On the other hand, when the content of Li ₂ O + Na ₂ O + K ₂ O increases, the overcoat layer reacts with the electrode and the resistor during firing, and the insulation resistance of the glass tends to decrease, and the dielectric strength characteristics of the electronic circuit May deteriorate. In addition, it becomes difficult to adjust the thermal expansion coefficient, and it is easily peeled off from the substrate after firing, and as a result, it is difficult to secure protection and insulation of the electrodes of the electronic circuit.

Li ₂ O is a component that lowers the softening point and adjusts the thermal expansion coefficient. The content of Li ₂ O is preferably 0 to 2%, more preferably 0 to 1.5%, and particularly preferably 0 to 1%. When the content of Li ₂ O increases, the overcoat layer, the electrode, and the resistor react with each other during firing, whereby the insulation resistance of the glass tends to decrease, and the withstand voltage characteristics of the electronic circuit may be deteriorated. . Moreover, acid resistance falls and it becomes easy to erode an overcoat layer with a plating solution, As a result, it becomes difficult to ensure protection and insulation of the electrode of an electronic circuit, etc.

Na ₂ O is a component that lowers the softening point and adjusts the thermal expansion coefficient. The content of Na ₂ O is preferably 0 to 10%, more preferably 1 to 10%, still more preferably 2 to 9%, and particularly preferably 3 to 8%. When the content of Na ₂ O increases, the coefficient of thermal expansion increases, and after firing, it easily peels from the substrate, and as a result, it becomes difficult to ensure protection and insulation of the electrodes of the electronic circuit.

K ₂ O is a component that adjusts the thermal expansion coefficient while lowering the softening point. The content of K ₂ O is preferably 0 to 10%, more preferably 0.1 to 7%, and particularly preferably 1 to 5%. When the content of K ₂ O increases, the coefficient of thermal expansion increases, and after firing, it is easily peeled off from the substrate, and as a result, it becomes difficult to ensure protection and insulation of the electrodes of the electronic circuit.

Al ₂ O ₃ is a component that stabilizes the glass. The content of Al ₂ O ₃ is 0 to 10%, preferably 0.1 to 9%, more preferably 1 to 8%, and particularly preferably 2 to 7. When the content of Al ₂ O ₃ decreases, the glass tends to become unstable. On the other hand, when the content of Al ₂ O ₃ is increased, the softening point is unreasonably raised and it becomes difficult to fire at a temperature of 840 ° C. or lower.

The molar ratio (SiO ₂ + ZrO ₂ ) / (B ₂ O ₃ + ZnO) is greater than 2.8, preferably 3 or more, more preferably 3.5 or more, still more preferably 4 or more, and particularly preferably 4.5 to 10.5. When the molar ratio (SiO ₂ + ZrO ₂ ) / (B ₂ O ₃ + ZnO) is too small, the acid resistance tends to be lowered.

In addition to the above components, various components may be introduced as long as the required characteristics are not impaired. For example, in order to lower the softening point, Cs ₂ O, Rb ₂ O, or the like may be introduced up to 5%, particularly up to 1%, alone or in total. Moreover, in order to stabilize glass and to improve water resistance and acid resistance, Y ₂ O ₃ , La ₂ O ₃ , Ta ₂ O ₅ , SnO ₂ , TiO ₂ , Nb ₂ O ₅ , P ₂ O ₅ , CuO , CeO ₂ , V ₂ O _5, etc. may be introduced in a total amount or independently up to 10%, particularly up to 1%.

  PbO is a component that increases acid resistance and lowers the softening point. However, since it is an environmental load substance, it is preferable to avoid substantial introduction.

  The powder material of the present invention is a powder material containing glass powder and ceramic powder made of the above glass composition, wherein the glass powder content is 50 to 100% by mass and the ceramic powder content is 0 to 50. It is preferable that it is mass%.

  The glass powder can be produced, for example, by forming molten glass into a film and then crushing and classifying the obtained glass film.

The average particle diameter D ₅₀ of the glass powder is preferably 3.0 μm or less, and the maximum particle diameter D _max is preferably 20 μm or less. When the particle size of the glass powder is too large, large bubbles are likely to remain in the fired film. Here, the “average particle diameter D ₅₀ ” refers to a value measured with a laser diffractometer, and in an accumulated particle size distribution curve based on volume when measured by a laser diffraction method, the accumulated amount is accumulated from the smaller particle. The particle diameter is 50%. “Maximum particle size D _max ” refers to a value measured by a laser diffractometer, and in the volume-based cumulative particle size distribution curve measured by the laser diffraction method, the accumulated amount is accumulated from the smaller particle. The particle size is 99%.

  The content of the ceramic powder is preferably 40% by mass or less, 30% by mass or less, 20% by mass or less, 10% by mass or less, 5% by mass or less, and particularly less than 1% by mass. When the ceramic powder is too much, the ratio of the glass powder is relatively reduced, and it becomes difficult to form a dense overcoat layer, and the overcoat layer is easily eroded by the plating solution. As a result, it becomes difficult to ensure protection and insulation of the electrodes of the electronic circuit. If ceramic powder is added, the thermal expansion coefficient, mechanical strength, and acid resistance of the powder material can be adjusted.

  Various materials can be used as the ceramic powder. For example, one or more of alumina, zircon, zirconia, mullite, silica, cordierite, titania, tin oxide, and the like can be added.

  In the powder material of the present invention, the softening point is preferably 840 ° C. or less, more preferably 830 ° C. or less, still more preferably 820 ° C. or less, and particularly preferably 810 ° C. or less. If the softening point is too high, in order to obtain a dense overcoat layer, the firing temperature must be increased, in which case the electrode and the powder material react with each other and the characteristics of the electrode and the like are likely to deteriorate. .

In the powder material of the present invention, the thermal expansion coefficient is preferably 55 to 80 × 10 ⁻⁷ / ° C., particularly preferably 60 to 75 × 10 ⁻⁷ / ° C. If it does in this way, after forming an overcoat layer on a soda-lime glass substrate or an alumina substrate, it will become easy to prevent curvature of a substrate and exfoliation of an overcoat layer. Here, the “thermal expansion coefficient” is an average value measured in a temperature range of 30 to 300 ° C. by a thermomechanical analyzer (TMA).

  The powder material paste of the present invention is a powder material paste containing a powder material and a vehicle, wherein the powder material is the above powder material. Here, the “vehicle” is a material for dispersing glass powder to form a paste, and is usually composed of a thermoplastic resin, a plasticizer, a solvent, and the like.

  The powder material paste can be prepared by preparing a powder material and a vehicle, and mixing and kneading them at a predetermined ratio.

  A thermoplastic resin is a component which improves the film | membrane intensity | strength after drying, and is a component which provides a softness | flexibility. The content of the thermoplastic resin in the powder material paste is preferably 0.1 to 20% by mass. As the thermoplastic resin, polybutyl methacrylate, polyvinyl butyral, polymethyl methacrylate, polyethyl methacrylate, ethyl cellulose and the like are preferable, and it is preferable to use one or more of these.

  The plasticizer is a component that controls the drying speed and imparts flexibility to the dry film. The content of the plasticizer in the powder material paste is preferably 0 to 10% by mass, particularly 0.1 to 10% by mass. It is preferable that the plasticizer is substantially free of phthalic acid compounds such as butylbenzyl phthalate, dioctyl phthalate, diisooctyl phthalate, dicapryl phthalate, and dibutyl phthalate. In this way, the environmental load can be reduced. From an environmental viewpoint, as a plasticizer, adipic acid compounds such as diisobutyl adipate and dibutoxyethyl adipate, sebacic acid compounds such as dibutyl sebacate and di-2-ethylhexyl sebacate, and citric acid compounds such as tributyl acetylene citrate Etc., and it is preferable to use one or more of these.

  The solvent is a component for dissolving the thermoplastic resin. The content of the solvent in the powder material paste is preferably 10 to 30% by mass. As the solvent, terpineol, diethylene glycol monobutyl ether acetate, 2,2,4-trimethyl-1,3-pentadiol monoisobutyrate and the like are preferable, and it is preferable to use one or more of these.

  In order to form an overcoat layer on an electronic circuit using a powder material paste, first, on the electronic circuit on which electrodes, resistors, etc. are formed, the powder material paste is applied by a screen printing method, a batch coating method, After forming a coating layer having a predetermined thickness, it is dried to obtain a dry film. Then, a predetermined overcoat layer (baked film) can be formed by baking the dried film at a temperature of 740 to 840 ° C. for 5 to 20 minutes. If the firing temperature is too low or the firing time (holding time) is too short, the dried film will not sinter sufficiently, 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 electrode and the powder material react with each other, and the characteristics of the electrode and the like easily deteriorate.

  Although the method of using a powder material paste has been described as an example of the method for forming the overcoat layer, other methods can be adopted. For example, a method such as a green sheet method, a photosensitive paste method, or a photosensitive green sheet method may be adopted.

  The glass composition, powder material and powder material paste of the present invention are preferably used for forming an overcoat layer, and are preferably used for forming an overcoat layer of a thermistor. In the thermistor, an electrode is formed on the thermistor material, and an overcoat layer is formed thereon. Then, after the overcoat layer is formed, a plating process using a plating solution is performed. As described above, the glass composition, the powder material, and the powder material paste of the present invention can be fired at a temperature of 840 ° C. or less and do not easily peel from the thermistor material without containing a large amount of PbO. Moreover, since it is hard to be eroded by the plating solution, it is particularly suitable for this application.

  Hereinafter, based on an Example, this invention is demonstrated in detail. The present invention is not limited to the following examples. The following examples are merely illustrative.

  Table 1 shows Examples (Sample Nos. 1 to 4) and Comparative Examples (Sample Nos. 5 and 6) of the present invention.

Each sample was prepared as follows. First, raw materials were prepared and mixed uniformly so as to have the glass composition shown in the table. Next, after putting it in a platinum crucible and melting at 1400 to 1550 ° C. for 2 hours, it was formed into a film shape, pulverized with a ball mill, and then classified by airflow to obtain an average particle diameter D _{50 of} 3.0 μm or less and a maximum particle diameter D _max. A glass powder of 20 μm or less was obtained. The softening point and thermal expansion coefficient were evaluated using the obtained glass powder.

  The softening point is the value of the fourth inflection point when measured with a macro-type differential thermal analyzer.

  The coefficient of thermal expansion was determined by forming each glass powder under pressure and sintering it densely at a temperature of (softening point + 10) ° C., then processing it to a diameter of 5 mm and a length of 20 mm to obtain a measurement sample. It is the average value measured in the temperature range of 30-300 degreeC with an analyzer (TMA).

  Next, the glass powder and vehicle (terpineol containing 5% by mass of ethyl cellulose and 3% by mass of tributyl acetylcitrate) were mixed and kneaded in a three-roll mill to obtain a powder material paste. Furthermore, after applying the powder material paste onto the thermistor material by screen printing so that a fired film (overcoat layer) of about 10 μm can be obtained, the coated film is dried, and (softening point + 10) ° C. in an electric furnace. Was fired at a temperature of 10 minutes to form a fired film. Acid resistance was evaluated using the obtained substrate with a fired film. Specifically, the substrate with the fired film was immersed in 5% by mass sulfuric acid at 40 ° C. for 1 hour, washed with water, dried, then measured for mass reduction, and the mass reduction ratio before and after immersion was evaluated. In addition, it means that acid resistance is so low that the ratio of mass reduction is large.

  As is apparent from the table, sample No. 1-4 had a low softening point and thermal expansion coefficient and good acid resistance. On the other hand, sample No. No. 5 had a low softening point but poor acid resistance. Sample No. 6 had good acid resistance, but had a high coefficient of thermal expansion.

  The glass composition, the powder material and the powder material paste of the present invention are particularly suitable for the formation of an overcoat layer, particularly for the formation of an overcoat layer of a thermistor. It can also be applied to uses such as a binding material) and a sealing material.

Claims (9)

A powder material containing glass powder and ceramic powder,
The glass powder content is 50 to 100% by mass, the ceramic powder content is 0 to 50% by mass,
Glass powder, as a glass composition, in _{mol%, SiO 2 50~70%, B} 2 O 3 4 super _{~15%, ZrO 2 6~15%,} 1~10% ZnO, CaO 0~8.5%, MgO + CaO + SrO + BaO 0.5-20%, Li ₂ O + Na ₂ O + K ₂ O 0.5-15%, Al ₂ O ₃ 0-10%, molar ratio (SiO ₂ + ZrO ₂ ) / (B ₂ O ₃ + ZnO) A powder material characterized in that is greater than 2.8. 2. The MgO content is 5 mol% or less, the CaO content is 8 mol% or less, the SrO content is 15 mol% or less, and the BaO content is 15 mol% or less. The powder material described in 1. Li ₂ O content 2 mol% or less, Na ₂ O content 10 mol% or less, and according to claim 1 or 2 content of _{K 2} O, characterized in that 10 mol% or less Powder material . The powder material according to any one of claims 1 to 3, which is substantially free of PbO. Powder material according to claim 1, the content of the ceramic powder is equal to or less than 1 wt%. The powder material according to any one of claims 1 to 5, wherein a softening point is 840 ° C or lower. Powder material according to any one of claims 1 to 6, characterized in that used for forming the overcoat layer. In a powder material paste containing a powder material and a vehicle,
A powder material paste, wherein the powder material is the powder material according to any one of claims 1 to 7.   9. The powder material paste according to claim 8, which is substantially free of a phthalic acid compound.