JP2000264676A - Low melting point glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain low melting point glass which has a low softening point and excellent water resistance and does not contain lead, cadmium and fluorine by compounding ZnO, B2O3 and TeO2 in a specific ratio. SOLUTION: This low melting point glass substantially comprises ZnO, B2O3 and TeO2 in amounts of 41-70 mol.%, 27-49 mol.% and 1-25 mol.%, respectively, based on the total amount of the oxides. The low melting point glass preferably has a softening point of 500-630 deg.C, a glass transition temperature of >=450 deg.C and an average linear expansion coefficient of 50×10-7/ deg.C to 90×10-7/ deg.C at 50-250 deg.C. A glass ceramic composition which can control the linear expansion coefficient of the sintered product can be obtained by adding a filler such as zircon, alumina or silica to the powder of the low melting point glass. The low melting point glass is used by mixing the powder of the low melting point glass with a vehicle which comprises a resin component, such as ethyl cellulose, dissolved in a solvent such as butylcarbitol acetate, coating a treatment target article with the obtained glass paste, and then sintering the coated glass paste.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sealing of electronic parts,
The present invention relates to a low-melting glass used for coating and the like.

[0002]

2. Description of the Related Art Low melting glass is widely used for sealing and coating electronic parts. For example, it is used for sealing a panel and a funnel in a cathode ray tube, sealing, coating, and forming ribs in a flat display panel such as a plasma display panel (PDP) and a fluorescent display tube (VFD).

In recent years, there has been a demand for such a low-melting glass that does not contain lead or cadmium. ZnO-B ₂ O ₃ -TeO ₂ based low melting glass is known as such. For example, JP-A-7-330372, does not contain lead or _{cadmium, ZnO-B 2 O 3 -TeO} 2 based low melting glass and fluorine as essential components is disclosed.

[0004]

However, when a fluorine-containing low-melting glass is applied to sealing a panel and a funnel in a cathode ray tube, a phenomenon called an emission slump may occur and the brightness of the cathode ray tube may be reduced. That is, in the cathode ray tube manufacturing process, the panel and the funnel are heated (baked out) by sealing the inside with a low melting point glass and then evacuating the inside thereof. At this time, fluorine gas may be generated from the low melting point glass.
As a result, the electron gun mounted inside the cathode ray tube may be deteriorated by the fluorine gas, and the brightness of the cathode ray tube may be reduced.

[0005] Baking out is similarly performed in PDPs, VFDs, and the like, and fluorine gas is generated from low-melting glass containing fluorine, which may cause various troubles. An object of the present invention is to provide a low-melting glass that is used for sealing, coating, and the like of electronic components, does not contain lead or cadmium, and does not contain fluorine.

[0006]

According to the present invention, there is provided a method for producing ZnO, comprising:
₂ O ₃ 27-49%, TeO ₂ 1-25%,
A low-melting glass comprising:

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The low-melting glass of the present invention is usually powdered to seal and coat electronic parts (glass substrates, etc.).
Used for etc. The powder of the low-melting glass of the present invention is mixed with a vehicle and made into a paste to form a glass paste. Mixing with the vehicle is performed using a mortar, a three-roll mill, or the like. The glass paste is applied to an object to be sealed, covered, and the like (hereinafter simply referred to as an object), for example, a predetermined portion of a glass substrate, and fired. A solution obtained by dissolving resin components such as ethyl cellulose, nitrocellulose and butyral resin in a solvent such as α-terpineol, butyl carbitol acetate, isoamyl acetate and the like is used as the vehicle.

The softening point of the low melting point glass of the present invention is 630 ° C.
The following is preferred. If the temperature exceeds 630 ° C., there is a possibility that the low-melting glass may not be sufficiently softened and flown in firing usually performed in sealing and coating of electronic components, that is, firing at a firing temperature of 650 ° C. or lower. More preferably 620 ° C
The temperature is particularly preferably at most 600 ° C. The softening point of the low melting point glass of the present invention is preferably 500 ° C. or higher. If it is lower than 500 ° C., there is a possibility that it reacts with the object during firing. It is more preferably at least 530 ° C, particularly preferably at least 560 ° C.

The glass transition point of the low melting glass of the present invention is as follows:
Preferably it is 450 ° C. or higher. If it is lower than 450 ° C., the softening point may be too low. More preferably 46
0 ° C. or higher. The low-melting glass of the present invention may be one that crystallizes during firing or one that does not crystallize.

The average linear expansion coefficient of an object at 50 to 250 ° C. is often in the range of 60 × 10 ^{−7 to} 100 × 10 ⁻⁷ / ° C. (The average linear expansion coefficient at 50 to 250 ° C. is simply referred to as Expansion coefficient). From the viewpoint of expansion matching between these objects and the low-melting glass of the present invention, the low-melting glass of the present invention has an expansion coefficient of 50 × 10 ^{−7 to} 90 × 1.
It is preferably 0 ^-7 / ° C. The lower limit of the expansion coefficient is more preferably 54 × 10 ⁻⁷ / ° C. Also,
The upper limit is more preferably 85 × 10 ⁻⁷ /
° C, more preferably 80 × 10 ^-7 / ° C, and particularly preferably 65 × 10 ^-7 / ° C.

By adding a filler to the low-melting glass powder of the present invention, a glass-ceramic composition that can be used for sealing, coating, etc. of electronic parts can be obtained. By selecting an appropriate filler and adjusting the amount thereof, the expansion coefficient of a fired body obtained by firing the glass ceramic composition can be controlled. As fillers used to control the expansion coefficient of the fired body to 60 × 10 ^{−7 to} 90 × 10 ⁻⁷ / ° C., zircon, cordierite, alumina, aluminum titanate, mullite, silica, β-U Cryptite, β-spodumene, β-quartz solid solution, and the like.

A heat-resistant pigment may be added to the low-melting glass powder or the glass-ceramic composition of the present invention for adjusting the color tone. Examples of the heat-resistant pigment include white pigments such as alumina, titanium oxide, and zirconia; black oxides such as a composite oxide of iron and manganese; a composite oxide of copper and chromium; and a composite oxide of cobalt and chromium. .

The low-melting glass of the present invention is substantially in the following mol% based on oxides: ZnO: 41 to 70%, B ₂ O ₃ : 2
_{7~49%, TeO 2: 3~25%} , preferably made of. More preferably, ZnO: 44-68%, B _{2
O 3: 28~44%, TeO 2} : 3~17%, it is. Particularly _{preferably, ZnO: 45~65%, B 2} O 3: 28~
_{40%, TeO 2: 3~16%} , it is.

The composition of the low melting point glass of the present invention will be described below by simply expressing mol% as%. ZnO is a component that stabilizes glass. If it is less than 41%, devitrification tends to occur, and vitrification becomes difficult. It is preferably at least 44%, more preferably at least 45%. If it exceeds 70%, the water resistance decreases, and application to sealing, coating, etc. of electronic components becomes difficult. Preferably 68% or less, more preferably 65%
% Or less.

B ₂ O ₃ is a network former.
If it is less than 27%, glass formation becomes difficult. Preferably 2
8% or more. If it exceeds 49%, the water resistance is reduced, and it is difficult to apply it to sealing, coating, etc. of electronic components. It is preferably at most 44%, more preferably at most 40%.

TeO ₂ is a component that lowers the softening point. If it is less than 1%, the effect is small. It is preferably at least 3%, more preferably at least 5%, particularly preferably at least 8%. If it exceeds 25%, the water resistance decreases, and the sealing of electronic parts,
It becomes difficult to apply to coating, etc. It is preferably at most 17%, more preferably at most 16%.

The low-melting glass of the present invention substantially comprises the above-mentioned components. In addition, P ₂ O ₅ , SiO ₂ , Al ₂ O ₃ , M
gO, CaO, SrO, BaO, Y 2 O 3, TiO 2, Z
rO ₂ , MoO ₃ , WO ₃ , MnO, Fe ₂ O ₃ , Rh
₂ O ₃ , CoO, NiO, PdO, CuO, Ag ₂ O, B
i ₂ O ₃ and rare earth oxides (La ₂ O ₃ , CeO ₂ , etc.) may be added up to 5% by weight in total.

The low-melting glass of the present invention can be used, for example, for sealing a panel and a funnel in a cathode ray tube, a plasma display panel (PDP), a fluorescent display tube (VFD),
Sealing, covering, etc. in flat display panels such as
It is suitable for rib formation, but its use is not limited to these.

[0019]

EXAMPLES Raw materials were prepared and mixed so as to obtain a glass having a composition represented by mol% in the columns from ZnO to TeO _{2 in the} table. As a raw material, boric acid and / or boron oxide, zinc oxide, and tellurium oxide were used. The prepared and mixed raw materials were put in a platinum crucible and melted at 1200 ° C. for 30 minutes. The molten glass thus obtained was poured into a stainless steel roller and flaked, and then pulverized for 100 minutes with an alumina ball mill to obtain a glass frit.

The following measurements were made on the glass frit. Glass transition point (° C.), softening point (° C.), crystallization temperature (° C.): Measured by DTA at a rate of 10 ° C./min. Those having a glass transition point of 450 ° C. or higher and a softening point of 630 ° C. or lower are preferable.

Expansion coefficient (× 10 ⁻⁷ / ° C.): The glass flakes before powdering were re-melted, poured out onto a stainless steel plate, and gradually cooled at a temperature near the glass transition point. The obtained glass was processed into a rod shape of 2 mm × 20 mmφ, and the average linear thermal expansion coefficient at 50 to 250 ° C. was measured with a thermal differential dilatometer using quartz glass as a standard sample. 50 × 10 ^{-7 to} 90 × 10
It is preferably ^-7 / ° C.

Water resistance (%): The same sample as the sample for measuring the expansion coefficient was immersed in water at 80 ° C. for 2 hours, and the weight loss rate was determined from the weight before and after immersion. 0.5% or less is preferable.

Examples 1 to 4 are Examples and Examples 5 to 7 are Comparative Examples. In Example 4, no crystallization peak was observed in the measurement of DTA, and the crystallization temperature could not be measured. In Example 7, devitrification was remarkable, and a stable glass could not be obtained.

[0024]

[Table 1]

[0025]

According to the present invention, it is possible to provide a low melting point glass which is excellent in water resistance, does not contain lead or cadmium, and does not contain fluorine.

Continued on the front page F-term (reference) 4G062 AA08 AA09 BB08 CC10 DA01 DB01 DC04 DC05 DD01 DE05 DE06 DF01 EA01 EA10 EB01 EC01 ED01 EE01 EF01 EG01 FA01 FA10 FB01 FC01 FD01 FE01 FF01 FG01 FH01 FJ01 FK01 GC01 FL01 HH05 HH07 HH09 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM07 MM10 MM12 NN30 NN32

Claims (1)

[Claims] 1. A by mol% of a substantially following _{oxides, ZnO 41~70%, B 2 O} 3 27~49%, TeO 2 1~25%, low melting point glass made of.