KR102210424B1 - Solvent composition for bonding sapphire - Google Patents

Abstract

The solvent composition for bonding sapphire of the present invention includes polyethylene glycol (PEG), dibutyl phthalate and a surface activator, and the surface activator has a vapor pressure of 20 mmHg or less at 20°C, and the present invention for bonding sapphire The solvent composition has excellent silver workability, adhesion, and fairness, and the sapphire bonded by using it has excellent durability.

Description

Solvent composition for bonding sapphire {SOLVENT COMPOSITION FOR BONDING SAPPHIRE}

The present invention relates to a solvent composition for bonding sapphire.

Sapphire not only has high strength, but also has excellent optical properties due to its high transmittance in the ultraviolet and infrared wavelength bands. These sapphires are used in the manufacture of solar cells, light-emitting diodes (LEDs), laser diodes, and SOS (Silicon on Sapphire). In particular, large sapphires are used for unmanned aerial vehicle windows, image monitoring and targeting pods, deception systems, Its use is expanding in the military sector, such as tracking systems, submarine windows, and invisible armor.

However, it is very difficult to manufacture high-quality and large-sized sapphire, and productivity is also low.

Accordingly, interest in the technology of manufacturing a large window by bonding high-quality sapphire is increasing, but it is difficult to secure the strength and durability of the joined portion.

Although research on an adhesive composition or adhesive sheet having high strength after bonding with sapphire has been actively conducted, there is a problem that sufficient strength cannot be achieved only with the adhesive composition and the adhesive sheet.

Accordingly, there is a need for a solvent composition having improved workability and processability in order to not only improve the adhesive strength of the sapphire adhesive composition or the adhesive sheet, but also minimize the case where sapphire is incorrectly bonded.

An object of the present invention is to provide a solvent composition for bonding sapphire capable of improving the adhesive strength between the adhesive sheet and the sapphire.

Another object of the present invention is to provide a solvent composition for bonding sapphire with improved processability due to temporary bonding.

Another object of the present invention is to provide a solvent composition for bonding sapphire having appropriate volatility and excellent workability.

Another object of the present invention is to provide a solvent composition for bonding sapphire excellent in durability of the bonded sapphire.

All of the above and other objects of the present invention can be achieved by the present invention described below.

One aspect of the present invention relates to a solvent composition for bonding sapphire.

According to one embodiment, the solvent composition for bonding sapphire includes polyethylene glycol (PEG), dibutyl phthalate and a surface activator, and the surface activator has a vapor pressure of 20 mmHg or less at 20°C.

In a specific embodiment, the solvent composition for bonding sapphire may include 15 to 35 parts by weight of polyethylene glycol (PEG), 15 to 35 parts by weight of dibutyl phthalate, and 35 to 55 parts by weight of a surface activator.

In addition, the polyethylene glycol (PEG) may have a weight average molecular weight of 550 to 900.

In addition, the dibutyl phthalate and the surface activator may be included in a weight ratio of 1:1 to 3:1.

In addition, the surface activator may include at least one of butyl carbitol, triton X-100, and triacetin.

In addition, the surface activator may include triton X-100 and triacetin, and the composition includes 15 to 35 parts by weight of the triton X-100 and the It may contain 15 to 35 parts by weight of triacetin.

The present invention can improve the adhesive strength between the adhesive sheet and the sapphire, temporary bonding is possible, not only improves fairness, but also has excellent workability due to appropriate volatility, and a sapphire bonding solvent composition having excellent durability of the bonded sapphire It has the effect of providing.

1 is a simplified perspective view of a large sapphire window bonded using a sapphire bonding solvent composition according to an embodiment of the present invention.
2 is a schematic cross-sectional view of a large sapphire window bonded using a sapphire bonding solvent composition according to an embodiment of the present invention.

Hereinafter, specific examples of the present application will be described in more detail with reference to the accompanying drawings. However, the technology disclosed in the present application is not limited to the specific examples described herein and may be embodied in other forms.

However, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present application may be sufficiently conveyed to those skilled in the art. In the drawings, in order to clearly express the constituent elements of each device, the size of the constituent elements, such as width or thickness, is slightly enlarged. In addition, although only some of the components are shown for convenience of description, those skilled in the art will be able to easily grasp the remaining parts of the components.

When it is described as a whole from the observer's point of view when describing the drawings, and when one element is referred to as being positioned above or below another element, this means that the element is positioned directly above or below another element, or an additional element between those elements. It includes all meanings that can be intervened. In addition, those of ordinary skill in the relevant field will be able to implement the spirit of the present application in various other forms without departing from the technical spirit of the present application. In addition, the same reference numerals in the plurality of drawings refer to substantially the same elements.

Meanwhile, the singular expression described in the present application should be understood as including a plurality of expressions, unless the context clearly indicates otherwise, and terms such as'include' or'have' are described features, numbers, steps, To designate presence in an action, component, part, or combination thereof, but precludes the possibility of the presence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. It should be understood as not.

In addition, in this specification,'X to Y'indicating a range means'X or more and Y or less'.

In addition, in the present specification, the average particle diameter may mean (volume) average particle diameter (D50).

In addition, in the present specification, the weight ratio of the _MgO powder and the total amount of the TiO ₂ powder and the Y ₂ O ₃ powder may mean M _MgO :M _{(TiO2 + Y2O3)} . (Where M _MgO is the weight of MgO, M _{(TiO2 + Y2O3)} is the sum of the weight of TiO2 and Y2O3)

In addition, in the size of the specimen, t may mean the thickness.

In addition, parts by weight may be based on 100 parts by weight of the total composition, but may be used to mean a ratio between each component.

Solvent composition for bonding sapphire

The solvent composition for bonding sapphire according to the present invention includes polyethylene glycol (PEG), dibutyl phthalate, and a surface activator, and the surface activator has a vapor pressure of 20 mmHg or less at 20°C. The solvent composition for bonding sapphire of the present invention can improve the adhesive strength between the adhesive sheet and the plate sapphire by applying it to the surface of the adhesive sheet for bonding the plate sapphire. , Since the volatility of the sapphire bonding solvent composition is appropriate, the workability is excellent, and the durability of the bonded large sapphire window is excellent. In particular, the solvent composition for bonding sapphire of the present invention has been optimized to impart the above effect to the components of the following adhesive sheet, and specifically, the solvent composition for bonding sapphire of the present invention is an alumina (Al ₂ O ₃ )-based adhesive sheet, specifically alumina ( Al ₂ O ₃ ) was optimized for an adhesive sheet containing 50% by weight or more.

Hereinafter, each component will be described in detail.

The polyethylene glycol (PEG) is a solvent in the solvent composition for bonding sapphire, and serves as a dispersant in which each component can be well dispersed. Specifically, polyethylene glycol (PEG) may properly disperse dibutyl phthalate and a surface activator having a specific vapor pressure or higher.

The polyethylene glycol (PEG) may have a weight average molecular weight of 550 to 900, specifically 600 to 800. Within the above range, the viscosity of the sapphire bonding solvent composition is suitable as the solvent.

The polyethylene glycol (PEG) may be included in 15 to 35 parts by weight, specifically 20 to 30 parts by weight, more specifically 24 to 29 parts by weight, in the sapphire bonding solvent composition. In the above content range, the viscosity of the solvent composition for bonding sapphire is appropriate, and dispersion of each component is excellent.

The dibutyl phthalate has a high boiling point as a plasticizer, can maintain the solvent composition for bonding sapphire even during drying, and improves bonding between the adhesive sheet and the plate-shaped sapphire.

The dibutyl phthalate may be included in the sapphire bonding solvent composition in an amount of 15 to 35 parts by weight, specifically 20 to 30 parts by weight, and more specifically 24 to 29 parts by weight. In the above content range, the adhesiveness of the solvent composition for bonding sapphire is excellent, and since plate-shaped sapphire can be temporarily bonded when manufacturing a large sapphire window, there is an advantage of excellent processability and workability.

The surface activator softens the surface of the adhesive sheet, which will be described later, and activates the surface of the adhesive sheet so that it can be bonded to the plate-shaped sapphire, thereby improving the adhesion and bonding force between the adhesive sheet and the plate-shaped sapphire.

To this end, the surface activator has a vapor pressure of 20 mmHg or less at 20°C, for example, more than 0 mmHg and less than 20 mmHg, specifically more than 0 mmHg and less than 10 mmHg, more specifically more than 0 mmHg and less than 5 mmHg, more specifically It may be more than 0 mmHg and less than 2 mmHg. In the above vapor pressure range, it is possible to prevent excessive volatilization of the sapphire bonding solvent composition, thereby improving workability and processability, as well as improving adhesion as a separate component for volatilization control may not be included. There is this. Specifically, when the sapphire bonding solvent composition applies a surface activator having a vapor pressure exceeding the scope of the present invention, a separate component must be included for volatility control, and in this case, not only the adhesive strength is lowered, but also due to this Since temporary bonding is not easy, there is a problem that workability and fairness are not good.

The surface activator may be included in 35 to 55 parts by weight, specifically 40 to 53 parts by weight, more specifically 45 to 50 parts by weight, in the sapphire bonding solvent composition. Within the above range, the balance of fairness, workability and adhesion of the solvent composition for bonding sapphire is excellent.

In a specific embodiment, the surface activator may include at least one of butyl carbitol, triton X-100, and triacetin.

For example, the surface activating agent may include triton X-100 and triacetin, and the sapphire bonding solvent composition is included in the sapphire bonding solvent composition. triton X-100) 15 to 35 parts by weight, specifically 20 to 30 parts by weight, more specifically 24 to 29 parts by weight, and 15 to 35 parts by weight of the triacetin, specifically 20 to 30 parts by weight, more specifically It may contain from 24 to 29 parts by weight. In a specific embodiment, the solvent composition for bonding sapphire may include triton X-100 and triacetin in a weight ratio of 1.0:1 to 1.5:1, specifically 1.2 to 1.3. In the above content range, the surface of the adhesive sheet can be densely bonded to the plate-shaped sapphire with high strength.

In a specific embodiment, the dibutyl phthalate and the surface activator may be included in a weight ratio of 1:1 to 3:1. In the above content range, adhesion can be maximized, thereby improving processability and workability as temporary bonding of the plate-shaped sapphire is possible.

Adhesive sheet

The solvent composition for bonding sapphire of the present invention may be optimized for the adhesive sheet described below. The adhesive sheet may be formed of a sapphire adhesive composition, wherein the sapphire adhesive composition includes 80 to 180 parts by weight of an organic binder based on 100 parts by weight of the inorganic binder; 1 to 3 parts by weight of a dispersant; And 1 to 3 parts by weight of a plasticizer.

Hereinafter, each component will be described in detail.

The inorganic binder is 0.1 to 4 parts by weight of SiO ₂ powder based on 100 parts by weight of alumina (Al ₂ O ₃ ) powder; 0.001 to 0.5 parts by weight of MgO powder; 0.001 to 1 part by weight of TiO ₂ powder; And 0.005 to 1 part by weight of Y ₂ O ₃ powder; It may include.

Since the alumina (Al ₂ O ₃ ) powder is the same material as the main component of sapphire, it has a high adhesive strength by diffusion sintering with sapphire, and has the advantage of having a bonding strength similar to that of sapphire because the physical properties are also the same as sapphire.

The particle diameter (D50) of the Al ₂ O ₃ powder may be 0.1 μm to 10 μm. In a specific embodiment, the Al ₂ O ₃ powder may use two or more Al ₂ O ₃ powders having different particle diameters.

Al ₂ O ₃ powder has a particle size may be varied by various causes as well as the method are, for example, the Al ₂ O ₃ Al ₂ O ₃ powder has a powder particle size of 0.1㎛ to 1㎛ of the total amount of 55 to 70 Al ₂ O ₃ powder having a weight% and a particle diameter of 2 μm to 6 μm may be included in an amount of 30 to 45% by weight. In the above content range, the sapphire adhesive composition may have a more compact structure when sintered, and strength may be maximized.

The SiO ₂ powder serves as a sintering aid to lower the sintering temperature, and may increase the sintering density. The SiO ₂ powder may have an appropriate particle diameter depending on the purpose, but when the SiO ₂ powder having an average particle diameter (D50) of 10 nm to 1,000 nm, specifically 50 nm to 200 nm is applied, dispersion is good.

The Al ₂ O ₃ powder may be included in a range of 96 wt% or more, specifically 97 wt% to 99 wt%, of the total content of the inorganic binder. In this case, the bonding strength with sapphire is excellent, so that the strength after bonding is improved.

The silica (SiO ₂ ) powder may be included in an amount of 0.1 to 4 parts by weight, specifically 1 to 3 parts by weight, based on 100 parts by weight of the Al ₂ O ₃ powder. If the content is less than the above content range, the sintering temperature increases, the sintering density decreases, and thus the strength is deteriorated. When the content exceeds the content range, the sintering temperature decreases and the glass phase increases, thereby reducing the strength.

The magnesium oxide (MgO) powder serves to induce uniform particle growth to prevent abnormal particle growth at the end of sintering, and to further densify the particles. The MgO powder may have an appropriate particle diameter according to the purpose, but when a particle diameter of 0.1 μm to 10 μm, specifically 0.1 μm to 1 μm is applied, abnormal particle growth can be prevented and uniform densification is possible even when a small amount is used. Accordingly, since the adhesive composition is optically uniform after bonding with sapphire, there is an advantage of having high transparency and minimizing distortion and refraction of light.

The magnesium oxide (MgO) powder may be included in an amount of 0.001 to 0.5 parts by weight, specifically 0.005 to 0.3 parts by weight, and more specifically 0.01 to 0.1 parts by weight, based on 100 parts by weight of the Al ₂ O ₃ powder. If the content is less than the above content range, the effect of including the magnesium oxide (MgO) powder is insignificant, and when the content exceeds the content range, there is a fear that the strength is reduced due to excessive inhibition of particle growth.

The titanium dioxide (TiO ₂ ) powder has an effect of optimizing densification by controlling the densification rate. The titanium dioxide (TiO ₂ ) powder may have an appropriate particle size according to the purpose.

The titanium dioxide (TiO ₂ ) powder may be included in an amount of 0.001 to 1 parts by weight, specifically 0.01 to 0.5 parts by weight, based on 100 parts by weight of the Al ₂ O ₃ powder. In the above content range, there is an effect of optimizing particle growth and densification, and the final density can be increased.

The yttrium oxide (Y ₂ O ₃ ) powder has an effect of improving the strength by inducing appropriate particle growth to homogenize the microstructure.

The yttrium oxide (Y ₂ O ₃ ) powder may have an appropriate particle diameter according to the purpose, but when the average particle diameter (D50) is 0.1 μm to 10 μm, specifically 0.1 μm to 1 μm, the mechanical strength is There is an improvement effect.

The yttrium oxide (Y ₂ O ₃ ) powder may be included in an amount of 0.005 to 1 parts by weight, specifically, 0.008 to 0.5 parts by weight, and more specifically 0.01 to 0.1 parts by weight, based on 100 parts by weight of the Al ₂ O ₃ powder. If it does not reach the above content range, there is a disadvantage in that the effect of controlling particle growth and improving strength is insignificant, and when it exceeds the above content range, uniformity of the microstructure is lowered.

In particular, the composition for bonding sapphire includes yttrium oxide (Y ₂ O ₃ ) powder, so that uniform particle growth and densification are possible while minimizing the disadvantages of containing an excessive amount of magnesium oxide (MgO).

In a specific embodiment, the inorganic binder may include MgO powder and Y ₂ O ₃ powder in a weight ratio of 1:1 to 10:1, specifically 1:1 to 5:1. In the above content range, there is an advantage of not only improving strength by preventing excessive inhibition of grain growth, inducing appropriate grain growth, and homogenizing the microstructure, but also reducing an appropriate sintering temperature.

In addition, the inorganic binder may have a weight ratio of the sum of the MgO powder and the TiO ₂ powder and the Y ₂ O ₃ powder of 0.5:1 to 2:1. In the above content range, the balance of particle growth, densification and mechanical strength improvement is excellent.

The organic binder is not particularly limited, and for example, polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), or a mixture thereof may be used. The organic binder may be included in an amount of 80 to 180 parts by weight, specifically 100 to 160 parts by weight, based on 100 parts by weight of the inorganic binder. If it is not within the above range, the bonding force of the composition is lowered, making molding difficult, and if it exceeds the above range, mixing with the inorganic binder becomes difficult and moldability decreases.

The dispersant is not particularly limited, and for example, menhaden fish oil, ammonium salt, phosphate ester, or mixtures thereof may be used. The dispersant may be included in an amount of 1 to 3 parts by weight based on 100 parts by weight of the inorganic binder. If the content is not within the above range, the inorganic binder is not properly dispersed, resulting in sedimentation and agglomeration, and as a result, there is a problem that the molding and firing density decreases. Deteriorates formability.

The plasticizer is not particularly limited, and examples thereof include glycerol, polyethylene glycol, polyglycol, dibutylphthalate, dioctylphthalate, or mixtures thereof. The plasticizer may be included in an amount of 1 to 3 parts by weight based on 100 parts by weight of the inorganic binder. If the content is not within the above range, the plasticity of the organic binder is lowered, making it difficult to peel off from the PET film when forming the adhesive sheet, and as a result, a problem occurs during molding, and if it exceeds the above range, the viscosity becomes too high and molding becomes difficult. do.

The composition for bonding sapphire of the present invention may further contain a solvent. The solvent is not particularly limited, and for example, ethanol, toluene, methyl ethyl ketone, or a mixture thereof may be used. The solvent may be included in an amount of 10 to 30 parts by weight, specifically 16 to 26 parts by weight, based on 100 parts by weight of the inorganic binder. If the content is not within the above range, the viscosity increases, making it difficult to mix the bonding material composition, and if it exceeds the above range, the viscosity of the composition decreases, making molding difficult.

The adhesive sheet 20 may have a thickness of 100 μm to 220 μm. When the bonding film undergoes a heat treatment process to be described later, it shrinks by about 5% to 40%. Considering this, if the thickness of the adhesive sheet is less than the above range, the area of the bonding surface with the adjacent sapphire side is small, resulting in a decrease in strength, Conversely, when the above range is exceeded, the sintered density of the adhesive sheet is lower than that of sapphire, and the strength of the bonding surface may be lowered. In addition, the area of the adhesive sheet may be controlled to be 105% to 140% of the side area of the plate-shaped sapphire in consideration of the shrinkage rate.

Large sapphire window

Hereinafter, the present invention will be described with reference to FIGS. 1 and 2. 1 is a simplified perspective view of a large sapphire window bonded using a sapphire bonding solvent composition according to an embodiment of the present invention, and FIG. 2 is a sapphire bonding solvent composition according to a specific embodiment of the present invention. It is a schematic cross-sectional view of a large sapphire window.

Referring to FIGS. 1 and 2, the large sapphire window 100 may be manufactured by bonding two or more plate-shaped sapphires 10a and 10b. 1 and 2 illustrate manufacturing by bonding two plate-shaped sapphires, but it is not limited thereto, and it is apparent to those skilled in the art that a large sapphire window may be manufactured by bonding three or more plate-shaped sapphires.

The large sapphire window 100 may be formed through an adhesive sheet 20 between each of the plate-shaped sapphires 10a and 10b and bonding solvent layers 30a and 30b formed on both surfaces of the adhesive sheet 20. The large sapphire window formed in this way has excellent durability and can be used in technical fields that require high durability, such as aircraft windows, submarine windows, and transparent shields. The adhesive sheet 20 may be formed of the sapphire bonding composition, and the bonding solvent layers 30a and 30b may be formed of the sapphire bonding solvent composition.

Referring to FIGS. 1 and 2, the large sapphire window 100 may be bonded to each other at an angle θ that is not perpendicular to the length direction of the plate sapphire 10a and 10b. For example, the angle θ may be in the range of 35° to 55°. In this case, durability is improved due to an increase in the bonding area, and the bonding surface is visually recognized depending on the purpose in which the large sapphire window 100 is used. There is an advantage that can prevent it from becoming. At this time, the side surfaces of the plate-shaped sapphires 10a and 10b (surfaces perpendicular to the wide surface direction) are in a direction parallel to the C-axis of the sapphire crystal, specifically the M-axis direction, the A-axis direction, or the M-axis direction, and Although it may be advantageous to secure the transmittance to correspond to the A-axis direction, it is not limited thereto.

The adhesive sheet 20 and the bonding solvent layers 30a and 30b may be substantially the same as those described above.

Manufacturing method of large sapphire window

In the method for manufacturing a sapphire window according to the present invention, a large sapphire window 100 can be manufactured by bonding two or more plate-shaped sapphires 10a and 10b.

In one embodiment, the method of manufacturing a sapphire window comprises the steps of preparing an adhesive sheet by mixing and molding the sapphire adhesive composition; Temporarily bonding by placing the adhesive sheet 20 coated on both sides of the sapphire bonding solvent composition between the side surfaces of the two or more plate-shaped sapphires 10a and 10b; Pressing the two or more plate-shaped sapphires (10a, 10b) in the direction of the adhesive sheet (20); And subjecting the two or more plate-shaped sapphires 10a and 10b to a heat treatment at a temperature of 1675° C. to 1725° C. in a pressurized state to perform main bonding.

In the step of preparing the adhesive sheet 20, the sapphire adhesive composition may be molded at a temperature of 100° C. to 250° C. to form an adhesive sheet having a thickness of 100 μm to 220 μm. When the adhesive sheet 20 undergoes a heat treatment process to be described later, it shrinks by about 5% to 40%. Considering this, if the thickness of the adhesive sheet 20 is less than the above range, the area of the bonding surface with the adjacent sapphire side is small. If the strength is lowered, and on the contrary, when the above range is exceeded, the sintered density of the adhesive sheet is lower than that of sapphire, and the strength of the bonding surface may be lowered.

Temporary bonding can be performed by placing the adhesive sheet 20 coated on both sides of the sapphire bonding solvent composition between the side surfaces of the plate-shaped sapphire to be bonded and another plate-shaped sapphire (after placing the plate-shaped sapphire in the longitudinal direction). . At this time, the side surface of the plate-shaped sapphire (the surface perpendicular to the broad surface direction) is in a direction parallel to the C-axis of the sapphire crystal, specifically in the M-axis direction, A-axis direction, or M-axis direction and A-axis direction. Although it may be advantageous to secure the transmittance, the sapphire adhesive composition of the present invention can be applied regardless of the direction. In addition, the area of the adhesive sheet may be controlled to be 105% to 140% of the side area of the plate-shaped sapphire 10a, 10b in consideration of the shrinkage rate.

The coating of the solvent composition for bonding sapphire can be applied by methods known to those skilled in the art, such as spray coating and brush application, and the amount of application is 0.01g/cm ² to 0.8g/cm ² , specifically 0.1g/cm ² to 0.5g/ It can be applied in an amount of cm ² . In the above application amount range, the desired adhesion can be achieved.

After the temporary bonding, the plate-shaped sapphires 10a and 10b are pressed in the direction of the adhesive sheet 20 and heat-treated in that state to perform main bonding. In this case, the pressing may be performed by a separate jig, and the heat treatment may be performed at a temperature of 1675°C to 1725°C.

In an embodiment, the heat treatment may be performed in one step at the temperature, but is not limited thereto and may be performed in multiple steps, for example. For example, the heat treatment is heated at a rate of 3° C./min to 10° C./min from room temperature to a first heating temperature of 100° C. to 250° C., and maintained at the first heating temperature for 1 to 10 hours. 1 Heating at a rate of 3°C/min to 10°C/min from a heating temperature to a second heating temperature of 500°C to 650°C, maintaining at the second heating temperature for 3 to 12 hours, 1675 at the second heating temperature Heating at a rate of 5°C/min to 10°C/min to a third heating temperature of °C to 1725°C, maintaining at the third heating temperature for 6 to 12 hours, 1.5 from the third heating temperature to the second heating temperature Cooling at a rate of °C/min to 1.8 °C/min, and cooling from the second heating temperature to room temperature at a rate of 1 °C/min to 10 °C/min. If the heat treatment time or heat treatment temperature is out of the above range, there is a problem that the bonding of the bonding surface is not uniform, and the sintering density is lowered, so that the strength of the bonding surface is lowered.

In particular, it is preferable to heat treatment under vacuum between room temperature and the second heating temperature, and heat treatment under vacuum, argon or nitrogen atmosphere between the second heating temperature and the third heating temperature.

The sapphire window manufactured using the solvent composition for bonding sapphire of the present invention was measured by producing a 40mmx4mmx3mmt specimen according to the Korean Industrial Standard KSL-1591 using a universal test machine (33340 model. Instron). May be 330 MPa or more, for example, 330 MPa to 630 MPa, specifically 360 MPa to 530 MPa, and more specifically 380 MPa to 480 MPa.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention in any sense.

Contents not described herein can be sufficiently technically inferred by those skilled in the art, and thus description thereof will be omitted.

Example

Example 1

SiO ₂ powder 2.04 parts by weight, MgO powder 0.05 parts by weight, TiO ₂ powder 0.03 parts by weight and Y ₂ O ₃ powder 0.02 parts by weight based on 100 parts by weight of Al ₂ O ₃ powder, polyvinyl butyral (Aldrich, USA) 135 g, 2.5 g of phosphate ester (Sigma, USA), 2.5 g of polyethylene glycol (Sigma, USA), 12 g of toluene, and 8 g of ethanol were mixed, heated to 200°C, and cooled to prepare an adhesive sheet having a thickness of 200 μm. The adhesive sheet was prepared in an area corresponding to 130% of the adhesive area of the plate-shaped sapphire.

26.3 parts by weight of polyethylene glycol (PEG) with a weight average molecular weight of 700, 26.3 parts by weight of dibutyl phthalate, and 26.3 parts by weight of Triton X-100 as a surface activator (about 1 mmHg at 20℃ vapor pressure) and A sapphire bonding solvent composition containing 21.1 parts by weight of triacetin (at 20° C. vapor pressure of about 0.01 mmHg or less) was applied to both sides of the adhesive sheet in an amount of 0.2 g/cm ² using a brush and temporarily bonded. Then, a large sapphire window was manufactured through the following heat treatment process while pressing the plate-shaped sapphires in the direction of the adhesive sheet through the adhesive sheet using a jig.

[Heat treatment]

Heating from room temperature to 210℃ at a rate of 5℃/min, holding at 210℃ for 2 hours, heating at a rate of 5℃/min from 210℃ to 620℃, holding at 620℃ for 5 hours, holding at 620℃ to 1700℃ Heating at a rate of 10° C./min to, holding at 1700° C. for 10 hours, cooling from 1700° C. to 620° C. at a rate of 1.6° C./min, and cooling from 620° C. to room temperature at a rate of 10° C./min. At this time, the heat treatment was performed under vacuum between room temperature and 620°C, and between 620°C and 1700°C under an argon atmosphere. Thereafter, the sapphire bonding was completed by polishing the transmission surface for observation of the sapphire window.

Example 2

The solvent composition for bonding sapphire was prepared with a weight average molecular weight of 700 polyethylene glycol (PEG) 34 parts by weight, dibutyl phthalate 34 parts by weight, Triton X-100 (triton X-100) 16 parts by weight, and triacetin. ) A large sapphire window was manufactured in the same manner as in Example 1, except that 16 parts by weight were applied.

Example 3

The solvent composition for bonding sapphire was prepared with 21 parts by weight of polyethylene glycol (PEG) having a weight average molecular weight of 700, 21 parts by weight of dibutyl phthalate, 29 parts by weight of triton X-100, and triacetin. ) A large sapphire window was manufactured in the same manner as in Example 1, except that 29 parts by weight were applied.

Example 4

A large sapphire window was manufactured in the same manner as in Example 1, except that butyl carbitol (20° C. vapor pressure of about 0.01 mmHg) was applied instead of triton X-100 in the solvent composition for bonding sapphire. .

Comparative Example 1

A large sapphire window was manufactured in the same manner as in Example 1, except that the solvent composition for bonding sapphire was applied in 50 parts by weight of polyethylene glycol (PEG) having a weight average molecular weight of 700 and 50 parts by weight of dibutyl phthalate.

Comparative Example 2

Examples except that the solvent composition for bonding sapphire was applied with a weight average molecular weight of 700 polyethylene glycol (PEG) 34 parts by weight, triton X-100 (triton X-100) 34 parts by weight, and triacetin 32 parts by weight A large sapphire window was manufactured in the same manner as in 1.

Comparative Example 3

Except for applying the solvent composition for bonding sapphire with 26.3 parts by weight of polyethylene glycol (PEG) having a weight average molecular weight of 700, 26.3 parts by weight of dibutyl phthalate, and 47.4 parts by weight of methyl ethyl ketone (MEK, vapor pressure of about 78 mmHg at 20℃) Then, a large sapphire window was manufactured in the same manner as in Example 1.

Property evaluation method

Bending strength (MPa): A 40mmx4mmx3mmt specimen was prepared according to the KSL-1591 standard using a universal testing machine (Instron, USA) for the large sapphire windows prepared in Examples and Comparative Examples, and the measured 3-point bending strength was measured, and the following table It is shown in 1.

Bending strength (MPa) Example 1 470 Example 2 424 Example 3 415 Example 4 431 Comparative Example 1 247 Comparative Example 2 116 Comparative Example 3 355

As shown in Table 1, it can be seen that Examples 1 to 4 to which the solvent composition for bonding sapphire of the present invention is applied have excellent adhesive strength and high bending strength.In addition, the solvent composition for bonding sapphire is It can be seen that the bonding is possible to improve the processability, as well as the appropriate volatility to provide excellent workability.

On the other hand, it can be seen that Comparative Examples 1 and 2 that do not contain a surface activator or do not contain dibutyl phthalate have low bending strength due to a decrease in adhesive strength. In addition, Comparative Example 3 in which methyl ethyl ketone (MEK) having a vapor pressure exceeding the scope of the present invention was applied showed some degree of bending strength, but when applied after leaving it in the air for 30 minutes, the bending strength fell to 200 MPa or less. There was a problem with low surname

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, but may be manufactured in various different forms, and those of ordinary skill in the technical field to which the present invention pertains to the technical idea of the present invention. It will be appreciated that it can be implemented in other specific forms without changing any or essential features. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting.

10a, 10b: plate-shaped sapphire 20: adhesive sheet
30a, 30b: bonding solvent layer 100: large sapphire window

Claims (6)

15 to 35 parts by weight of polyethylene glycol (PEG);
15 to 35 parts by weight of dibutyl phthalate; And
Including; a surface activator comprising 15 to 35 parts by weight of triton X-100 and 15 to 35 parts by weight of triacetin,
The surface activator is a solvent composition for bonding sapphire having a vapor pressure of 20 mmHg or less at 20°C.
delete The method of claim 1,
The polyethylene glycol (PEG) is a solvent composition for bonding sapphire having a weight average molecular weight of 550 to 900.
The method of claim 1,
The solvent composition for bonding sapphire containing the dibutyl phthalate and the surface activator in a weight ratio of 1:1 to 1.17:1.

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