KR100639698B1 - Lead free material having high insulation capacity for sealing sheath heater module - Google Patents

Abstract

Lead-free material with high insulation capacity for sealing sheath heater module is provided to meet to WEEE and RoHS and to be free from hazardous substances such as Pb, Cd, Cr^(+6), etc. by fabricating Bi2O3-B2O3-ZnO-R2O based material instead of typical PbO-B2O3-ZnO material to form the lead-free product. The lead-free material is based on Bi2O3-B2O3-ZnO-R2O and produced by the steps of: melting 85-90wt.% of Bi2O3, 9-12wt.% of B2O3 and 1-3wt.% of ZnO; adding 1wt.% of Al2O3, 0.5wt.% of SiO2 and 0.3wt.% of BaO2 to the molten material; solidifying the mixture; and milling the solidified material to result in powder form of moldable material. The obtained material shows unlimited M ohms independent of humidity and exposure time at room temperature, has inherent physical properties including coefficient of thermal expansion ranging from 70 to 110 x 10^(-7). The moldable powder is used to fabricate a bead form of molded product by biaxial molding process.

Description

Lead free material having high insulation capacity for sealing sheath heater module

1 is a graph showing the DTA curve of the sealing material of Shizuhita of the present invention.

2 is a graph showing a change in the coefficient of thermal expansion curve according to the addition of the R ₂ O component and the control of the B ₂ O ₃ content ratio in the sealing material of Shizuhita of the present invention.

Figure 3 is a photograph of the molded powder powder.

4 is a photograph of a bead molded product compression molded.

FIG. 5 is a photograph photographing a state in which a bead, which is an insulating material, is inserted into Shizuhi for the heat treatment sealing process.

The present invention relates to a highly insulating non-combustible material for sealing a Shizuhita module. More specifically, the present invention provides the Waste Electrical and Electric Equipment (WEEE) Directive on Restriction and Disposal of Environmentally Harmful Substances (EU) and Restriction of Hazardous Substances (RoHS). The present invention relates to a highly insulating non-combustible material for sealing a Shizuhita module which does not contain regulatory components such as Pb, Cd, Cr ^+6, and the like.

A sheath heater sealing material may be defined as a material used to form a closed structure in which two or more current inlet terminal portions exposed to air are protected from the effects of moisture. At this time, the physical properties of the material require electrical insulation, leakage current resistance and operating temperature stability at the applied voltage.

In particular, the sealing method of Shizuhita using ceramic insulating material has excellent electric insulation, leakage current, harsh environmental resistance such as operating temperature and humidity, and electric shock safety. It's a finishing touch

Currently, various electric / electronic module bonding or sealing materials including Shizuhita use a wide range of PbO-B ₂ O ₃ -ZnO component materials containing 75% by weight or more of PbO. When disposing of electricity and electronic devices, PbO contained in the module proceeds to the following reactions (1) and (2) by acid rain containing SO ₂ , NO _2, etc. Known.

PbO + H ₂ SO ₄ → PbSO ₄ + H ₂ O... … … … … … … … … … … … … … … (One)

PbO + NHO ₃ → Pb [NO ₃ ] ₂ + H ₂ O. … … … … … … … … … … … … … (2)

When the eluted Pb accumulates in the human body through groundwater and soil pollution, it affects the functions of human organs such as the central nervous system and the brain. Nevertheless, PbO-B ₂ O ₃ -ZnO system has been widely used to date due to easy synthesis, accumulated know-how and attractive price due to long use.

However, with the recent tightening of regulations on environmentally harmful substances in the EU, there is a strong demand for the development of functional materials to replace the existing PbO-B ₂ O ₃ -ZnO system.

However, at present, there is no report on the manufacture and commercialization of sealing materials for Shizuhita and electric and electronics that comply with EU environmental regulations. This is because Shizuhita's insulating materials, which have important properties such as electrical insulation, leakage current resistance, and operating temperature stability at high voltage, have different properties from those of semiconductor module sealing materials.

At present, there are no known domestic development reports on commercialization of sealing materials with low Pb content in Shizuhita modules. This is believed to be due to weak technicality because only a specialized company with advanced materials-related technology can guarantee quality continuity. Nevertheless, the practical importance of lead-free sealing materials that comply with EU RoHS and WEEE directives is essential for overcoming technical barriers, environmental issues, and continued expansion of the EU market.

Accordingly, the present inventors have similar electrical characteristics and physical properties to replace the existing PbO-B ₂ O ₃ -ZnO-based Shizuhita module sealing material (Korean Patent No. 523,805), and comply with EU WEEE and RoHS Directive. It is an object of the present invention to provide a highly insulating lead-free material for sealing a Shizuhita module that does not contain a regulatory component such as Pb, Cd, Cr ⁺⁶ as an inorganic insulating material for electric and electronics.

In order to achieve the object as described above, the high insulation non-combustible material for sealing of the Shizuhita module of the present invention is made of Bi ₂ O ₃ -B ₂ O ₃ -ZnO-R ₂ O as a basic composition and Al ₂ O ₃ It is composed of a molded powder powder prepared by solidifying and then pulverizing the parent material by adding SiO ₂ , BaO ₂ , specific gravity 6.9 ± 0.5g / cc, glass transition temperature 400 ℃, and 70 ~ 110X10 ^-7 coefficient of thermal expansion In addition to having a material intrinsic properties such as, and at room temperature, it is characterized in that the insulation characteristics of the ∞ MΩ value, etc. are expressed regardless of the humidity and exposure time.

Shizuhita high insulation non-combustible material for sealing of the present invention is the basic composition of the Bi ₂ O ₃ -B ₂ O ₃ -ZnO-R ₂ O system, for example, Bi ₂ O ₃ 85 to 90% by weight, 12 to 9% by weight of B ₂ O ₃ and 3 to 1% by weight of ZnO in a mixer in a batch batch of melted and synthesized in a platinum crucible after Al ₂ O ₃ 1% by weight, SiO ₂ 0.5 The parent material is added with 0.3% by weight of BaO ₂ .

According to the present invention, as described above, by adding Al ₂ O ₃ , SiO ₂ , and BaO ₂ to the content of Bi ₂ O ₃ in the sealing process appearing in the Bi ₂ O ₃ -B ₂ O ₃ -ZnO-R ₂ O system. It is possible to suppress the reduction reaction (Reduction reaction), and to obtain a uniform amorphous phase (Distortion) without distortion in the parent material synthesis. And it becomes possible to shape | mold biaxially, without the control of the easy thermal expansion coefficient which satisfy | fills the bonding characteristic between sealing materials, and without adding a dispersing agent, a mold release agent, a lubricant, etc.

According to the present invention, the molten and synthesized parent material is passed through the melt between twin rollers having a speed of about 0 to 100 rpm / min and an interval of about 1 mm to give a ribbon at a cooling rate of about 105 to 109 ° C / S. solidify in the form of ribbon, and break up this Pb-free coolant and sift around 500 mesh. This particle distribution is a particle distribution range in which molding fluidity can be secured in a very simple method without a processing process such as a spray dryer for preparing particles before molding by adding a dispersant, a mold release agent, a lubricant, and the like. Therefore, when sifting out of the above range, molding fluidity cannot be secured.

As a binder, 0.3 wt% of polyethylene glycol dissolved in distilled water as a binder is added to the sifted particles and dried at 50 ° C. for 12 hours to obtain fluidity without adding a dispersant, mold release agent, lubricant, etc. 3), and when the molded powder powder is press-molded, a high insulation non-combustible material for sealing Shizuhita according to the present invention is produced from the bead molded body (see FIG. 4).

The high insulation non-combustible material for sealing Shizuhita of the present invention is a Bi ₂ O ₃ -B ₂ O ₃ -ZnO- SiO ₂ -Al ₂ O ₃ -BaO ₂ -R ₂ O-based material, and the material When applied to the module, it has insulation resistance of ∞MΩ in wet angle, Θ = 0 ° fusion, cold repetition, and high temperature heating submersion evaluation. As a result, it has safety features such as prevention of leakage current during heat generation and design withstand voltage characteristics. It becomes visible.

The present invention will be described in more detail based on the following examples.

Example

Synthesis of the base material of the Bi ₂ O ₃ -B ₂ O ₃ -ZnO-R ₂ O system, which is a basic composition of the high-insulating lead-free material for sealing of the Shizuhita module according to the present invention, is carried out by the following method.

First, the starting material is weighed as shown in Table 1 below.

TABLE 1

Ingredient Name weight% Bi ₂ O ₃ 85 to 90 B ₂ O ₃ 12 to 9 ZnO 3 to 1 SiO ₂ One BaO ₂ 0.5 Al ₂ O ₃ 0.3

Dry mixing is carried out for at least 11 hours in a mixer in order to maintain a uniform mixing state of the weighed starting material, Bi ₂ O ₃ , B ₂ O ₃ , ZnO. In general, a wet method using an aqueous solution or the like for uniform mixing may be a secondary method because secondary contamination may occur.

The mixed batch of batch is placed in a platinum crucible and melted and synthesized in an 780 ° C electric furnace. At this time, by adding Al ₂ O ₃ , SiO ₂ , BaO ₂ to the basic composition of Bi ₂ O ₃ -B ₂ O ₃ -ZnO-R ₂ O-based as shown in Table 1, it is possible to suppress the distortion and the reduction reaction.

The molten and synthesized parent material was solidified in the form of a ribbon at a cooling rate of 105 to 109 ° C / S by passing the melt between twin rollers having a speed of 0 to 100 rpm / min and a distance of 1 mm. .

DTA and thermal expansion (CTE) analysis results of the synthesized materials are shown in FIGS. 1 and 2, respectively.

In the DTA analysis data of FIG. 1, the glass transition temperature (Tg) is shown at 430 ° C., which shows that it is a basic material of Shizuhita which is suitable for the heat treatment standard process at 720 ° C. for 120 seconds. In addition, as shown in the CTE analysis of FIG. 2, the coefficient of thermal expansion changes according to the addition of the R ₂ O component and the adjustment of the B ₂ O ₃ content ratio. As the contents of B ₂ O ₃ and ZnO increase, CTE tends to decrease.

Table 2 below shows the ICP analysis data according to how the EU regulates the measurement of environmentally hazardous substances. The method used for the analysis is Pb and Cd detection ASTM C 169: 1992 (ICP-AES), Cr ^{6 +} is ISO 3856-5: 1984 (E) (UV / Vis.). Table 3 shows the results of XRF analysis of the bulk sample.

TABLE 2

ingredient mg / kg (ppm) How to measure Pb 30 ASTM C 169: 1992 (ICP-AES) CD Not detected ASTM C 169: 1992 (ICP-AES) Cr ^{6 +} Not detected ISO 3856-51984 (E) (UV / Vis.)

TABLE 3

ingredient wavelength ppm Pb 8368.5 Not detected CD 14.8 Not detected Cr ^{6 +} 2.6 Not detected

As shown in Table 2, the Pb detected in the ICP analysis was found to be 30 ppm, which did not reach the EU maximum allowable value (1,000 ppm). On the other hand, no Pb was detected in the XRF. This difference is termed judged as an error comes from the difference of the device, a value detected by 30 ppm in the ICP analysis, Pb, Cd, Cr ^{6 +} the like are analyzed that are not the EU regulations limit or less or self-detecting RoHS and WEEE instructions It was found that the material satisfies.

On the other hand, the lead-free (Pb-free) coolant was pulverized in a pot mill with a ZrO ₂ ball 64 rpm / min to sieve so that the average particle size distribution (D50) is about 500 mesh. 0.3 wt% of polyethylene glycol dissolved in distilled water was added to the sifted particles and dried at 50 ° C. or more for 12 hr to form a final powder powder. The molded powder powder was biaxially molded with a unit area and 300 kg / cm 2 pressure. Press-formed beads were placed in an electric furnace and heat-treated at 310 ° C.

Figure 3 of the accompanying drawings is a photograph of the molded powder powder, Figure 4 is a bead molded body compression-molded, Figure 5 is a photograph taken a form of inserting the bead insulated material in Shizuhita for the heat treatment sealing process. .

According to the standard process, the bead molded body of FIG. 4 was inserted into both terminals of the Shizuhita of FIG. 5 and sealed using the heat of combustion of butane torch (V: 620ml, W: 87g) for 120 seconds. The sealed Shizuhita was evaluated by the method on the following conditions.

Table 4 shows the RoHS system (Bi ₂ O ₃ -B ₂ O ₃ -ZnO-R ₂ O system) and the control group (PbO-B ₂ O ₃ -corresponding to Korean Patent No. 523,805) prepared in Examples of the present invention. ZnO-R ₂ O-based) shows the results for the physical and chemical evaluation items, the specific difference between the Example and the control was not confirmed. The number of Shizuhita samples used for the characterization was compared with each other in 20 sets of the control and the examples.

First, when the bead is inserted into both terminals of the Shizuhita and the torch starts to melt from the solid phase into the liquid phase from 30 seconds, when the inner wall of the pipe, the terminal pins and the sealing material are visually observed, the surface of the sealing material is glossy. Overall, a fused form of smooth and uniform application should be shown. However, when fusion occurs by heat treatment at this time, vibration or impact should be avoided for at least 10 seconds. The shizuhita in this state was immersed in the water at room temperature for 5 days, withdrawn and drained to maintain the ∞ MΩ value when the insulation resistance was measured after the terminal was drained.

Next, as the cold and heat repeat test, the insulation resistance of ∞ MΩ value was maintained when 10 times of repeated tests in which the Shizuhita held for 30 minutes in an electric furnace at 100 ° C. were immersed in water at room temperature for 30 minutes. Subsequently, as a high temperature heating immersion test, the insulation resistance of ∞ MΩ was maintained even when the insulation resistance was measured by immersing Shizuhita maintained in an electric furnace at 150 ° C. for 48 hours in water at room temperature.

Finally, as a thermal resistance test of the terminal part, the insulation resistance measured when the sealing terminal part was heated at 250 ° C. for 2 hours or more shows 10 MΩ (2 MΩ or more), so that the lead-free material of the embodiment of the present invention, which does not contain Pb, has a new concept. It was confirmed that the sealing material for the heater.

Sheath heater and an insulating sealing material of the present invention are lead-free _{Bi 2 O 3 -B 2 O 3} -ZnO-SiO 2 -Al 2 O 3 -BaO is ₂ -R ₂ O-based material, the material of the sheath heater module When applied, it has insulation resistance of ∞MΩ in wetness angle, fusion property with Θ = 0 °, cold repetition, and high temperature heating submersion evaluation. As a result, it has safety features such as prevention of leakage current during heat generation and design withstand voltage characteristics. It has an effect.

In particular, the material of the present invention not only has electrical functionality similar to that of conventional PbO-B ₂ O ₃ -ZnO-based sealing materials, but also contains no inorganic metals such as Pb, Cd, Cr ⁺⁶ , and the EU RoHS and WEEE Directive. It is satisfactory, and it is effective to secure the sealing material for shizuhita of the new eco-friendly concept which has high insulation functionality without containing PbO by domestic technology.

It is believed that this will contribute to the national technological competitiveness by eliminating the obstacles of the EU's electrical and electronic products, and it can be said that it belongs to a high-value item suitable for high-tech companies based on materials such as the applicant.

Claims (4)

Bi ₂ O ₃ -B ₂ O ₃ -ZnO-R ₂ O as a basic composition, Bi ₂ O ₃ 85 to 90% by weight, B ₂ O ₃ 9 to 12% by weight, ZnO 1 to 3% by weight of the dry mixture After melting and synthesizing, 1% by weight of Al ₂ O ₃ , 0.5% by weight of SiO ₂ , and 0.3% by weight of BaO ₂ are added, followed by pulverizing and then pulverizing the parent material. Specific gravity 6.9 ± 0.5 g / cc, glass transition temperature of 400 ℃, and the material intrinsic properties of the thermal expansion coefficient of 70 ~ 110 × 10 ^-7 and at the same time exhibits the characteristics of ∞ MΩ value regardless of humidity and exposure time Highly insulating, non-combustible material for sealing Shizuhita modules. delete The polyethylene powder according to claim 1 or 2, wherein the molded powder powder is a Pb-free coolant of the parent material dissolved in distilled water as a binder in particles sieved with an average particle size distribution (D50) of 500 mesh. A highly insulating, non-combustible material for sealing a Shizuhita module, characterized in that it is dried after addition of 0.3% by weight. 4. The high insulation non-combustible material for sealing a Shizuhita module according to claim 3, wherein the molded powder powder can be made into a bead molded body by biaxial molding.

Images