Fluorinated tin-based glass frit and method for manufacturing same

Abstract

Provided is a super low melting SnOSnF2P2O5-based glass frit for which the firing temperature can be set to 200 C. or less and which has high water resistance and transparency. The fluorinated tin-based glass frit includes, in mol %, 30 to 70% of SnF2, 10 to 30% of P2O5, 10 to 40% of SnO, 0.1 to 10% of SnO2, 0 to 5% of In2O3, 0 to 5% of B2O3, and 0 to 5% of SiO2, and has a glass transition point of 160 C. or lower, a softening point of 180 C. or lower, and a maximum particle size of 100 m or less. The fluorinated tin-based glass frit has a visible light transmission rate of 80% or more at 200 C. and a thickness of 0.6 mm of a fired product thereof, and a rate of volume reduction of the fired product due to soaking in hot water at 85 C. for 24 hours is 2 vol. % or less.

Claims

1. A method for manufacturing a fluorinated tin-based glass frit comprising the steps of mixing a glass raw material powder, which includes, in mol %, 30 to 70% of SnF2, 10 to 30% of P2O5, 10 to 40% of SnO, 0.1 to 10% of SnO2, 0 to 5% of In2O3, 0 to 5% of B2O3, and 0 to 5% of SiO2, with a powder of an aromatic carboxylic acid, vitrifying the mixture by heating and melting it at 500 C. or lower, and thereafter pulverizing the mixture.

2. The method for manufacturing the fluorinated tin-based glass frit according to claim 1, wherein 100 parts by weight of the glass raw material powder is mixed with 0.5 to 2.5 parts by weight of the powder of the aromatic carboxylic acid.

3. The method for manufacturing the fluorinated tin-based glass frit according to claim 1, wherein the aromatic carboxylic acid is at least one type selected from among an aromatic monocarboxylic acid, an aromatic dicarboxylic acid, an aromatic dicarboxylic acid anhydride, and a mono or dialkyl ester of an aromatic dicarboxylic acid.

4. The method for manufacturing the fluorinated tin-based glass frit according to claim 1, wherein the glass frit has a glass transition point of 160 C. or lower, and a softening point of 180 C. or lower.

5. The method for manufacturing the fluorinated tin-based glass frit according to claim 1, comprising the glass raw material powder including, in mol %, 40 to 65% of SnF2, 15 to 30% of P2O5, 15 to 40% of SnO, 0.1 to 2% of SnO2, 0 to 5% of In2O3, 0 to 5% of B2O3, and 0 to 5% of SiO2.

Description

EXAMPLES

(1) The present invention shall now be described specifically by way of examples. Raw material oxides used in the following were all special grade reagents made by Wako Pure Chemical Industries, Ltd. and special grade reagents were similarly used for other analytical reagents, etc., as well.

Manufacturing Examples 1 to 21

(2) From each of mixtures, prepared by mixing respective powders of SnF.sub.2, SnO, P.sub.2O.sub.5 (for which ammonium hydrogenphosphate was used), SnO.sub.2, In.sub.2O.sub.3, B.sub.2O.sub.3, and SiO.sub.2 as glass raw materials at the proportions (mol %) indicated in Tables 1 and 2 below, and mixtures, prepared by further adding and mixing terephthalic acid powder as the aromatic carboxylic acid at the proportions (weight %) indicated in the Tables 1 and 2 below to the above glass raw material powders, 10 g were weighed out, placed in an alumina crucible of 50 cc volume, and heated at 380 to 500 C. for 40 minutes inside a muffle furnace to melt, the melt was thereafter poured into an alumina port and recovered, and from the cooled glass bar, a glass rod of 4 mm square and 11 mm length was cut out and from the remaining portion, a glass frit of a particle size of 100 m or less was manufactured by pulverizing and classifying with an automatic mortar.

(3) Using the respective glass frits and glass rods manufactured by the above method, the glass transition point [Tg], the softening point [Tf], the thermal expansion coefficient [CTE], the color tone, the optical transparency, and the water resistance were examined. The results are shown in the Tables 1 and 2 below. The measurement methods of the respective items are as follows.

(4) [Glass Transition Point and Softening Point]

(5) Using -alumina was used as a reference (standard sample), the glass transition point [Tg] and the softening point [Tf] of each glass frit were measured by a differential thermal analyzer (TG-8120, made by Rigaku Corporation) under the measuring conditions of a heating rate of 10 C./minute and a temperature range of 25 C. (room temperature) to 300 C.

(6) [Thermal Expansion Coefficient]

(7) The thermal expansion coefficient was measured by a thermal mechanical analyzer (TMA8310, made by Rigaku Corporation). For the measurement, the abovementioned glass rod was used as the measurement sample, the temperature was increased from room temperature to 100 C. at a rate of 10 C./minute, and an average thermal expansion coefficient a was determined. Also, quartz glass was used as a standard sample.

(8) [Color Tone]

(9) 0.020.001 g of each of the abovementioned glass frits were weighed out, packed in a metal container of 5 mm diameter and 5 mm depth, increased in temperature to 200 C. at a rate of 10 C./minute, fired at that temperature for 5 minutes, and the fired product was taken out and its color tone was examined.

(10) [Optical Transparency]

(11) Required amounts of the above glass frits were increased in temperature to 200 C. at a rate of 10 C./minute and fired at that temperature for 5 minutes to prepare button-shaped molded samples of 30 mm diameter and 0.6 mm thickness, and for each molded sample, an absorbance of a visible light range (average value for wavelengths of 380 to 780 nm) was measured by an absorbance measuring instrument (tradename UV-1800 made by Shimadzu Corporation) and, from the result, the optical transparency was evaluated according to the following four stages.

(12) . . . Visible light transmission rate is 85% or more.

(13) . . . Visible light transmission rate is 80% or more and less than 85%.

(14) . . . Visible light transmission rate is 50% or more and less than 80%.

(15) x . . . Visible light transmission rate is less than 50%.

(16) [Water Resistance]

(17) Each of the above glass rods was soaked in 500 mL of hot water at 85 C. for 24 hours and a weight change from an initial weight was calculated by the following formula.

(18) Weight change (%)=[1-measured weight (g)/initial weight (g)]100

(19) TABLE-US-00001 TABLE 1 Glass frit No. 1 2 3 4 5 6 7 8 9 10 Glass SnF.sub.2 49.2 47.0 47.0 47.0 41.8 41.8 41.8 44.7 44.7 44.7 composition SnO 26.3 25.1 25.1 25.1 36.8 36.8 36.8 30.8 30.8 30.8 (mol %) P.sub.2O.sub.5 23.5 26.9 26.9 26.9 20.4 20.4 20.4 23.5 23.5 23.5 SnO.sub.2 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Terephthalic acid (mol %) 1.0 3.0 1.0 2.0 1.0 2.0 Glass transition point 136 141 144 145 152 153 152 143 141 140 Tg ( C.) Softening point 156 166 167 171 165 166 167 157 155 158 Tf ( C.) Thermal expansion 168 163 160 163 159 158 157 160 162 161 coefficient (10.sup.7/ C.) Color tone Trans- Trans- Trans- Opaque Trans- Trans- Trans- Trans- Trans- Trans- parent parent parent parent parent parent parent parent parent Optical transparency X Water resistance 12.1 10.9 1.1 0.5 7.7 0.9 0.3 8.1 0.9 0.4 (weight change: %)

(20) The results of Table 1 show that although the glass frits obtained in Manufacturing Examples 1, 2, 5, and 8 are such that the proportions of the respective components of SnF.sub.2, SnO, P.sub.2O.sub.5, and SnO.sub.2 are within the prescribed ranges of the present invention and therefore are extremely low in the glass transition point [Tg] and the softening point [Tf] and may thus be said to be super low melting such as to enable the firing temperature to be set to 200 C. or lower, these do not conform to the fluorinated tin-based glass frit of the present invention because the water resistance is extremely poor. On the other hand, the glass frit obtained in Manufacturing Example 3, with which the proportions of the respective components are the same as in Manufacturing Example 2, the glass frits obtained in Manufacturing Examples 6 and 7, with which the proportions of the respective components are the same as in Manufacturing Example 5, and the glass frits obtained in Manufacturing Examples 9 and 10, with which the proportions of the respective components are the same as in Manufacturing Example 8, are, due to respectively being vitrified upon mixing appropriate amounts of terephthalic acid, which is an aromatic carboxylic acid, to the glass raw materials, extremely low in the glass transition point [Tg] and the softening point [Tf] and thus super low melting and yet significantly improved in water resistance and high in optical transparency and conform to the fluorinated tin-based glass frit of the present invention. And, with the glass frit obtained in Manufacturing Example 4, although excellent water resistance is obtained, the mixing amount of terephthalic acid is too large with respect to the glass raw materials such that carbides remain in the glass to make the glass opaque and poor in optical transparency.

(21) TABLE-US-00002 TABLE 2 Glass frit No. 11 12 13 14 15 16 17 18 19 20 21 Glass SnF.sub.2 34.0 31.1 43.5 43.5 43.5 43.5 61.2 47.8 46.9 47.8 46.9 composition SnO 48.7 44.4 33.4 33.1 33.1 32.4 18.7 25.4 24.9 25.4 24.9 (mol %) P.sub.2O.sub.5 16.3 23.5 23.0 23.0 23.0 23.0 17.1 25.3 24.8 25.3 24.8 SnO.sub.2 1.0 1.0 0.4 0.4 1.0 0.5 0.5 0.5 0.5 0.5 In.sub.2O.sub.3 0.6 B.sub.2O.sub.3 1.9 1.0 3.0 SiO.sub.2 1.0 3.0 Terephthalic acid (mol %) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Glass transition point 202 171 139 136 137 138 130 138 141 137 144 Tg ( C.) Softening point 214 188 151 153 144 145 144 146 155 149 158 Tf ( C.) Thermal expansion 148 149 160 162 160 159 165 158 154 159 153 coefficient (10.sup.7/ C.) Color tone Trans- Trans- Trans- Trans- Trans- Trans- Trans- Trans- Trans- Trans- Trans- parent parent parent parent parent parent parent parent parent parent parent Optical transparency Water resistance 5.2 5.6 5.3 3.0 0.9 0.6 0.9 0.7 0.3 0.7 0.4 (weight change: %)

(22) The results of Table 2 show that with a glass composition where, as in the glass frits obtained in Manufacturing Examples 11 and 12, the proportion of SnO is made higher than that prescribed by the present invention and the proportions of SnF.sub.2 and P.sub.2O.sub.5 are made relatively low, the water resistance, although slightly improved in comparison to Manufacturing Examples 1 and 2, is not satisfactory and the glass frits cannot be said to be super low melting because the glass transition point [Tg] and the softening point [Tf] are increased. Also, with a glass composition where, as in the glass frits obtained in Manufacturing Example 13, the proportions of the principal components of SnF.sub.2, SnO, and P.sub.2O.sub.5 are within the prescribed ranges of the present invention but SnO.sub.2 is not included, the glass frit is super low melting but poor in water resistance. On the other hand, the glass frits obtained in Manufacturing Examples 14 to 16, although being substantially the same as Manufacturing Example 13 in the proportions of the principal components, is super low melting and improved in water resistance due to including an appropriate amount of SnO.sub.2. However, the glass frit of Manufacturing Example 14 is insufficient in water resistance in comparison to the glass frits of Manufacturing Examples 15 and 16 that were vitrified upon mixing appropriate amounts of terephthalic acid to the glass raw materials. On the other hand, a glass frit, which, as with the glass frits obtained in Manufacturing Examples 17 to 21, is arranged with a glass composition where the proportions of the respective components of SnF.sub.2, SnO, P.sub.2O.sub.5, and SnO.sub.2 are within the prescribed ranges of the present invention and one type or two types among In.sub.2O.sub.3, B.sub.2O.sub.3, and SiO.sub.2 is or are added at appropriate amount or amounts as an optional component and is vitrified upon mixing an appropriate amount of terephthalic acid to the glass raw materials, is super low melting and yet significantly improved in water resistance and conforms to the fluorinated tin-based glass frit of the present invention.

Manufacturing Examples 22 to 23

(23) From each of mixtures, prepared by adding and mixing, besides terephthalic acid, the various additives indicated in Table 3 below at the proportions (weight %) indicated in the Table to the glass raw material powders of Manufacturing Example 2, 10 g were weighed out and, as in Manufacturing Examples 1 to 21 above, heated, melted, and recovered, and from the cooled glass bar, the same glass rod and glass frit as the above were manufactured. Using the respective glass frits and glass rods, the glass transition point [Tg], the softening point [Tf], the thermal expansion coefficient [CTE], the color tone, the optical transparency, and the water resistance were examined in the same manner as with Manufacturing Examples 1 to 21 above. The results are shown in the Table 3 below. With Manufacturing Examples 29 to 32, the recovered glass bars were opaque due to containing carbides and were thus judged to be of poor quality and measurements of the respective glass characteristics were omitted.

(24) TABLE-US-00003 TABLE 3 Glass frit No. 22 23 24 25 26 27 28 29 30 31 32 Glass SnF.sub.2 47.0 47.0 47.0 47.0 47.0 47.0 47.0 47.0 47.0 47.0 47.0 composition SnO 25.1 25.1 25.1 25.1 25.1 25.1 25.1 25.1 25.1 25.1 25.1 (mol %) P.sub.2O.sub.5 26.9 26.9 26.9 26.9 26.9 26.9 26.9 26.9 26.9 26.9 26.9 SnO.sub.2 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Additive Salicylic acid 1.0 3.0 1.0 1.0 (weight %) Phthalic acid 1.0 3.0 1.0 1.0 Terephthalic acid 1.0 1.0 Cellulose resin 1.0 Acrylic resin 1.0 Sucrose 1.0 Carbon powder 1.0 Recovery state when X X X X vitrified Glass transition point 146 138 142 141 145 139 138 Tg ( C.) Softening point 166 169 165 160 165 158 155 Tf ( C.) Thermal expansion 158 165 160 161 164 155 167 coefficient (10.sup.7/ C.) Color tone Trans- Trans- Trans- Trans- Trans- Trans- Trans- parent parent parent parent parent parent parent Optical transparency Water resistance 1.6 0.7 2.0 0.9 0.5 0.3 0.4 (weight change: %)

(25) From the results of Table 3, it is clear that even in cases where, as in Manufacturing Examples 22, 24, and 26 to 28, salicylic acid or phthalic acid is used as the aromatic carboxylic acid added to the glass raw materials or these acids are used in combination with terephthalic acid, glass frits that conform to the fluorinated tin-based glass frit of the present invention and are super low melting and yet excellent in optical transparency and water resistance are obtained. On the other hand, it can be understood that when, as in Manufacturing Examples 29 to 32, a cellulose resin, acrylic resin, sucrose, or carbon powder, etc., with which action as a reducing agent may be considered, is used in place of an aromatic carboxylic acid, opaque glass of poor quality is formed due to remaining of carbides of these substances. Also, as in Manufacturing Examples 23 and 25, even in a case where salicylic acid or phthalic acid is used, the optical transparency degrades if the mixing amount is too large.