JP2008303077A - Insulating protective coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating coating glass material and sealing glass material, from which an insulating protective coating film can be formed in the form of a single layer and the generation of bubbles caused by a reaction with an electrode can be suppressed and which are excellent in flatness and wear resistance and required in the development of electronic material substrates represented by thermal print heads. <P>SOLUTION: The insulating coating glass material and sealing glass material each contains, by weight, 0-12% SiO<SB>2</SB>, 10-32% B<SB>2</SB>O<SB>3</SB>, 22-42% ZnO, 10-30% Bi<SB>2</SB>O<SB>3</SB>, 17-40% RO(MgO+CaO+SrO+BaO), and 0-5% Al<SB>2</SB>O<SB>3</SB>, and further, may contain 0.1-4.5 wt.% filler. The insulating coating glass material and sealing glass material each has a coefficient of thermal expansion at 30-300°C of (65-90)×10<SP>-7</SP>/°C and a softening point of 500-620°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an insulating coating material and a sealing material for an electronic material substrate typified by a thermal print head or the like.

  The thermal recording type image recording device has a simple structure and is advantageous for downsizing, price reduction, weight reduction, and power consumption. It is widely used for various recording applications including various printers. in use.

  If the thermal print head used in this thermal recording system is, for example, a line head, it has a heat generating part in which a resistance heating element is formed in a line on an insulating substrate, and an electrode. Then, the heating part is brought into contact with the recording paper or the recording paper via the ink ribbon, etc., and the recording information is sequentially inputted as electric signals to each resistance heating element to perform the recording in the main scanning direction, and the recording paper is run along with the recording information. A two-dimensional recorded image is obtained by performing recording in the sub-scanning direction.

  In the thermal head, a glaze layer, a resistance heating element made of an oxide, and an electrode made of aluminum (Al) are formed on an insulating substrate through a film forming process of each layer. Thus, the electrode pattern formed on the resistance heating element allows the resistance heating element between the electrodes to generate heat finely. And the protective layer is formed on them so that a resistance heating element and an electrode may be covered.

  With respect to the protective layer in the thermal print head having the above-described configuration, for the purpose of obtaining a high-definition image on the recording paper, it is required that the surface of the protective layer has a high smoothness, that is, a low surface roughness. High wear resistance against sliding is required.

  Conventionally, as such a protective layer, for example, a protective layer by a thin film manufacturing technique such as a CVD method or a sputtering method is used. There is a problem that it takes a long time, and the film forming apparatus is expensive and requires a large manufacturing cost.

On the other hand, as a low-cost protective layer, a protective layer made of glass formed by a thick film manufacturing technique such as printing and baking is also frequently used. In the glass of this protective layer, a filler of microcrystalline particles such as alumina (Al ₂ O ₃ ) or zirconia (ZrO ₂ ) is used in order to increase the wear resistance and to improve the thermal conductivity. It is included.

  In a thick film type thermal recording head in which a thermal resistance layer, an electrode, a heating resistor layer, and a protection layer are sequentially laminated on an insulating substrate, the protection layer faces the heating resistor layer. A two-layer type has been proposed that includes a lower layer of an alumina filler-containing glass layer and an amorphous glass layer in which the content of alumina filler formed in the upper layer is zero or less than that in the glass layer (Patent Literature). 1). Thereby, the surface smoothness of the upper layer can be reduced.

  Further, in the thermal head in which a resistance heating element and an electrode for supplying power to the resistance heating element are formed on an insulating substrate and a protective film made of filler-containing glass is formed so as to cover the heating resistor and the electrode. There has been proposed a protective film containing a filler having a low specific gravity and a very small average particle diameter of 0.5 μm or less and protruding the filler on the surface of the protective layer (see Patent Document 2).

Furthermore, in a thermal head comprising a glaze substrate, a heating element portion and a conductive layer portion provided on the glaze substrate, and an abrasion-resistant glass layer formed thereon, the heating element portion and the conductive layer portion Further, it has been proposed to provide a wear-resistant glass layer through an oxide thin film such as silicon oxide / alumina having a thickness of at least 300A. The oxide thin film is formed by CVD or sputtering, and the wear-resistant glass is printed and fired with lead borosilicate glass (SiO ₂ —B ₂ O ₃ —PbO) plus a small amount of alumina or potassium oxide. (See Patent Document 3).

Thus, the adhesion strength between the glass layer and the heating resistor portion can be increased, and the glass layer also has a function of preventing diffusion of the antioxidant film of the heating resistor portion and the impurity heating resistor portion.
JP 63-216760 A Japanese Patent No. 3477194 JP-A-61-229570

  However, it has been found that the configuration described in each of the above publications has the following problems.

  That is, when the protective layer has a two-layer structure as described in JP-A-63-216760 and JP-A-61-229570, although the surface of the protective layer can be made smooth, the process for producing the protective layer As a result, the material and production cost increase. Furthermore, lamination by CVD or sputtering is another factor that increases production costs.

  Also, PbO-based glass has low wear resistance and cannot withstand sliding of printing paper. For this reason, the composite glass ceramic containing a large amount of ceramic filler as disclosed in Japanese Patent No. 3477194 tries to improve the wear resistance, but the ceramic filler segregates on the upper part of the protective layer and is flat. There was a problem that the print paper was damaged. Further, since the filler having a very small particle diameter is easily aggregated and becomes secondary particles, the surface layer tends to be abnormal protrusions, and is very expensive and expensive.

  Further, when alkali-containing glass is used, the reaction with the coated electrode is remarkable, so that reaction bubbles are generated and the performance of the thermal print head is deteriorated.

  Further, when an attempt is made to suppress the reaction of the electrode with a glass having a high softening point, since the firing temperature is high, the electrode is deteriorated and the resistance value of the heating element is greatly changed, so that the constituent materials are restricted.

  The present invention has been completed as a result of diligent research conducted by the present inventors in view of the above circumstances. The purpose of the present invention is to provide a thermal head in which a protective layer made of glass is formed as a single layer. An object of the present invention is to provide a material for a protective coating that enhances the wear resistance while ensuring the properties and suppresses the reaction with the electrode.

The present invention, in the insulating coated glass material and sealing glass material for an electronic material substrate represented by a thermal print head or the like, the composition of the glass material, the SiO ₂ by weight% 0~12, B ₂ O ₃ 10 to 32, ZnO 22 to 42, Bi ₂ O ₃ 10 to 30, RO (MgO + CaO + SrO + BaO) 17 to 40, Al ₂ O ₃ 0 to 5 It is a glass material.

  Moreover, it is said insulating film glass material and sealing glass material characterized by containing 0.1 wt%-4.5 wt% filler.

Furthermore, the above-mentioned insulating coated glass material and sealing, wherein the coefficient of thermal expansion at 30 ° C. to 300 ° C. is (65 to 90) × 10 ⁻⁷ / ° C., and the softening point is 500 ° C. or more and 620 ° C. or less. It is a glass material.

  Furthermore, it is an electronic material substrate characterized by using the above-mentioned insulating coated glass material and sealing glass material.

  Furthermore, it is a substrate for a thermal print head characterized by using the above-mentioned insulating coating glass material and sealing glass material.

The present invention, in the insulating coated glass material and sealing glass material for an electronic material substrate represented by a thermal print head or the like, the composition of the glass material, the SiO ₂ by weight% 0~12, B ₂ O ₃ 10 to 32, ZnO 22 to 42, Bi ₂ O ₃ 10 to 30, RO (MgO + CaO + SrO + BaO) 17 to 40, Al ₂ O ₃ 0 to 5 It is a glass material.

SiO ₂ is a glass forming component and can form a stable glass, and is contained in an amount of 0 to 12% (wt%, the same applies hereinafter). If it exceeds 12%, the softening point of the glass rises and the firing temperature rises, so that the electrode as the constituent material deteriorates or the resistance value of the heating element changes greatly. More preferably, it is 1 to 7% of range.

B ₂ O ₃ is a glass-forming component similar to SiO ₂ , facilitates glass melting, suppresses an excessive increase in the thermal expansion coefficient of glass, and imparts appropriate fluidity to the glass during baking. It is preferable to make it contain in 10 to 32% in glass. If it is less than 10%, the fluidity of the glass becomes insufficient and the sinterability is impaired. On the other hand, if it exceeds 32%, the stability of the glass is lowered. More preferably, it is 13 to 27% of range.

  ZnO is a component that lowers the softening point of the glass and adjusts the thermal expansion coefficient to an appropriate range, and is preferably contained in the range of 22 to 42% in the glass. If it is less than 22%, the effect cannot be exhibited, and if it exceeds 42%, the stability deteriorates. More preferably, it is 23 to 35% of range.

Bi ₂ O ₃ is a component that lowers the softening point of the glass and adjusts the thermal expansion coefficient to an appropriate range, and is preferably contained in the range of 10 to 30% in the glass. If it is less than 10%, the effect cannot be exhibited, and if it exceeds 30%, the wear resistance of the glass deteriorates. More preferably, it is 13 to 28% of range.

  RO (CaO, SrO, BaO) lowers the softening point of glass and improves sinterability. It is preferable to make it contain in a glass at 17 to 40%. If it is less than 17%, the softening point of the glass is not sufficiently lowered, and the sinterability is impaired. On the other hand, if it exceeds 40%, the thermal expansion coefficient of the glass becomes too high. More preferably, it is 20 to 35% of range.

Al ₂ O ₃ is a component that improves the stability of the glass and is preferably contained in the range of 0 to 5%. If it exceeds 5%, the softening point becomes too high. More preferably, it is 0 to 4% of range.

R ₂ O (Li ₂ O, Na ₂ O, K ₂ O) lowers the softening point of glass, imparts moderate fluidity, and adjusts the thermal expansion coefficient to an appropriate range, and is in the range of 0 to 1%. You may make it contain. If it exceeds 1%, reaction bubbles with the electrode are generated.

In addition, CuO, TiO ₂ , V ₂ O ₅ , MnO ₂ , CoO, NiO, CeO ₂ , La ₂ O ₃ , In ₂ O ₃ , SnO ₂ , TeO ₂ , Fe ₂ represented by general oxides. O ₃ , ZrO ₂ or the like may be added in an amount of 0 to 1% within a range in which the thermal expansion coefficient and the softening point are not changed.

  By substantially not containing PbO, it is possible to eliminate the influence on the human body and the environment. Here, “substantially free of PbO” means an amount of PbO mixed as an impurity in the glass raw material. For example, if it is in the range of 0.3 wt% or less in the low-melting glass, there is almost no influence on the adverse effects described above, that is, the influence on the human body and the environment, the insulation characteristics, etc., and it is not substantially affected by PbO. Become.

Further, the glass can contain 0.1 wt% to 4.5 wt% filler. If it is 4.5% or more, the flatness is deteriorated due to the protrusion of the filler, or separation from the glass occurs. Preferably it is 2 to 4% of range. As the filler, general Al ₂ O ₃ , ZrO ₂ or the like can be used.

The coefficient of thermal expansion at 30 ° C. to 300 ° C. may be (65 to 90) × 10 ⁻⁷ / ° C., and the softening point may be 500 ° C. or more and 650 ° C. or less. When the thermal expansion coefficient is outside (65 to 90) × 10 ⁻⁷ / ° C., problems such as peeling of the coating film and warping of the substrate occur when the thick film is formed. In addition, when the softening point exceeds 620 ° C., there arises a problem that the electrode is deteriorated due to baking at the time of forming the protective film. When the softening point is lower than 500 ° C., the resistance value of the heating resistor layer changes greatly. Preferably, it is 500 degreeC or more and 600 degrees C or less.

  This insulating coating glass material and sealing glass material are suitable for an electronic material substrate, a thermal printing substrate, and the like.

  Furthermore, it is a glass paste made of the above insulating coating material and an organic vehicle. Any organic vehicle may be used as long as it is generally used for glass pastes, and it is represented by a resin such as ethyl cellulose dissolved in an organic solvent such as α-terpineol or butyl carbitol acetate. By mixing with an organic vehicle and providing it as a glass paste, it can be used as a material in various fields.

  Hereinafter, a description will be given based on examples.

(Production of low melting point glass mixed paste)
The fine silica sand as a SiO _{2 source,} a boric acid as a B 2 _{O 3} source, a zinc oxide as a ZnO source, lithium carbonate as Li ₂ O source, sodium carbonate as Na ₂ O source, potassium carbonate as _{K 2} O source Cupric oxide as the CuO source, manganese dioxide as the MnO ₂ source, magnesium carbonate as the MgO source, calcium carbonate as the CaO source, strontium carbonate as the SrO source, barium carbonate as the BaO source, Bi ₂ O ₃ Bismuth oxide was required as a source. After preparing these as a desired low melting glass composition, it puts into a platinum crucible, heat-melts in 1000-1300 degreeC for 1-2 hours in an electric heating furnace, Examples 1-8 of Table 1, Table 1 The glass of the composition shown in 2 comparative examples 1-5 was obtained.

  A part of the glass was poured into a mold, made into a block shape, and used for measurement of thermal properties (thermal expansion coefficient, softening point). The remaining glass was flaked with a rapid cooling twin roll molding machine and sized with a pulverizer into a powder having an average particle size of 0.5 to 4 μm and a maximum particle size of less than 15 μm.

Next, paste oil composed of α-terpineol and butyl carbitol acetate was mixed with ethyl cellulose as a binder and the above glass powder and filler to prepare a paste having a viscosity of about 300 ± 50 poise. The filler used was ZrO ₂ and SiO ₂ with an average grain size of 2 to 5 μm.

(Formation of insulating coating)
The paste was applied to an alumina substrate having a thickness of 2 to 3 mm and a size of 100 mm square so that the film thickness after baking was about 10 μm, and an application layer was formed using an applicator. Subsequently, after drying, the insulating protective coating layer was formed by baking at 650 ° C. or lower for 10 to 60 minutes.

  The flatness was determined to be OK when the surface roughness Ra value calculated by a stylus type surface scan meter was 0.3 μm or less.

Abrasion resistance is OK when the formed protective film is slid on 10,000 times under the condition of abrasive paper # 4000; load of 100 g / cm ² and the decrease in film thickness is 20% or less. Judged.

  The suppression of the electrode reaction was determined by microscopic observation of the insulating protective film and the electrode interface, or cross-sectional SEM observation.

(result)
The low melting point glass composition and various test results are shown in the table.

  As shown in Examples 1 to 8 in Table 1, within the composition range of the present invention, the flatness, wear resistance, and suppression of electrode reaction bubbles were significantly superior to those of the prior art.

  On the other hand, Comparative Examples 1 to 5 in Table 2 that depart from the composition range of the present invention, as in the prior art, have noticeable electrode reaction bubbles, or do not exhibit preferable physical properties, and an insulating coated glass material such as a thermal print head. And it cannot be applied as a sealing glass material.

Claims (6)

In an insulating coating glass material and a sealing glass material for an electronic material substrate, the composition of the glass material is 0 to 12 for SiO ₂ , 10 to 32 for B ₂ O ₃ , 22 to 42 for ZnO, Bi. the _{2 O 3 10~30, RO (MgO} + CaO + SrO + BaO) of 17 to 40, insulative coating glass material and the sealing glass material, characterized in that the _Al 2 _{O 3} containing 0-5. The insulating coated glass material and the sealing glass material according to claim 1, wherein the filler contains 0.1 wt% to 4.5 wt% filler. The coefficient of thermal expansion at 30 ° C to 300 ° C is (65 to 90) × 10 ^-7 / ° C, and the softening point is 500 ° C or higher and 620 ° C or lower. Coating glass material and sealing glass material. A substrate for electronic materials, wherein the insulating coated glass material and the sealing glass material according to any one of claims 1 to 3 are used. A substrate for a thermal print head, wherein the insulating coated glass material and the sealing glass material according to any one of claims 1 to 3 are used. A glass paste comprising the insulating coating material according to any one of claims 1 to 3 and an organic vehicle.