JP6469390B2 - Glass material and manufacturing method thereof - Google Patents

Description

  The present invention relates to a glass material suitable as a material for a cover member or the like for protecting a medical treatment instrument such as an endoscope, and a manufacturing method thereof.

  Medical endoscopes are sterilized in a high temperature and high humidity environment using an autoclave before and / or after use. Devices such as a CCD camera and illumination are provided at the distal end portion of the endoscope. If these are directly exposed to a high temperature and high humidity environment in an autoclave, they may cause deterioration or failure. Therefore, a cover member for protecting each device is provided at the distal end portion of the endoscope.

  The cover member is required to have high chemical durability so that it can withstand a high temperature and high humidity environment during sterilization. The endoscope is attached to the tip of a movable tube inserted into the body. Due to the mobility, there is a risk that damage due to a collision will occur during use, and the cover member is also required to have mechanical strength. Conventionally, sapphire has been used as a material for a cover member that satisfies the above characteristics (see, for example, Patent Document 1).

JP-A-10-108823

  Since sapphire is an expensive material, there is a need for a cheaper alternative material. For example, chemically strengthened glass is a relatively inexpensive and high-strength material, but has a problem of poor chemical durability because it contains a large amount of alkali components.

  In view of the above, an object of the present invention is to provide a glass material that has high strength and excellent chemical durability and is relatively inexpensive, and a method for producing the same.

The glass material of the present invention contains Al ₂ O ₃ and SiO ₂ as main components, and has a crack resistance of 3N or more. In the present invention, “containing Al ₂ O ₃ and SiO ₂ as main components” means containing 50% or more of Al ₂ O ₃ and SiO ₂ as a glass composition in a total amount of mol%.

The glass material of the present invention preferably contains 35% or more of Al ₂ O ₃ in mol%.

Glass material of the present invention, in _{mol%, Al 2 O 3 35~80%} , and preferably contains _SiO 2 20 to 65%.

The glass material of the present invention is preferably mol%, and the content of R ₂ O (R is at least one selected from Li, Na and K) is preferably 10% or less.

  The glass material of the present invention preferably has a particle size of 0.1 mm or more.

  The glass material of the present invention is preferably used as a cover member for a medical treatment instrument.

  The glass material of the present invention is preferably used as an optical lens.

  The method for producing a glass material according to the present invention is a method for producing the above glass material, wherein the glass material is heated and melted in a state where the glass material is suspended and held above the molding surface of the mold. After obtaining molten glass, the method includes a step of obtaining a glass material by cooling the molten glass.

  According to the present invention, it is possible to provide a glass material that is high in strength, excellent in chemical durability, and relatively inexpensive.

It is typical sectional drawing which shows one Embodiment of the apparatus for manufacturing the glass material of this invention. It is typical sectional drawing which shows another embodiment of the apparatus for manufacturing the glass material of this invention. FIG. 3 is a schematic plan view showing a part of a molding surface in the manufacturing apparatus of FIG. 2. It is a typical perspective view which shows one Embodiment of the cover member for endoscopes which consists of a glass material of this invention. It is typical sectional drawing which shows the example which mounts and uses the cover member for endoscopes which consists of a glass material of this invention in the front-end | tip part of an endoscope. In an Example, it is a graph which shows the crack generation rate in each load.

The glass material of the present invention contains Al ₂ O ₃ and SiO ₂ as main components. Below, the preferable range of the content of each component and its reason are demonstrated. In the following description regarding the content of each component, “%” means “mol%” unless otherwise specified.

Al ₂ O ₃ is a component that improves crack resistance and chemical durability. The content of Al ₂ O ₃ is preferably 35% or more, more preferably 35 to 80%, still more preferably 45 to 75%, particularly preferably 55 to 70%. Most preferably, it is 60 to 70%. When the content of Al ₂ O ₃ is too small, the effect is difficult to obtain. On the other hand, when the content of Al ₂ O ₃ is too large, there is a tendency for vitrification tends to be difficult.

SiO ₂ is a component that forms a glass skeleton. The content of SiO ₂ is preferably 20% or more, more preferably 20 to 65%, further preferably 25 to 55%, particularly preferably 30 to 45%, 30 to Most preferably, it is 40%. If the content of SiO ₂ is too small, vitrification tends to be difficult. On the other hand, if the content of SiO ₂ is too large, cracks Resistance tends to decrease.

In the glass material of the present invention, the content of Al ₂ O ₃ + SiO ₂ is 50% or more, preferably 70% or more, more preferably 90% or more, and more preferably 95% or more. preferable. When the content of Al ₂ O ₃ + SiO ₂ is too small, cracks resistance and chemical durability tends to decrease.

  In addition to the above components, the glass material of the present invention may contain the following components.

For example, in order to improve the refractive index, the glass material of the present invention contains La ₂ O ₃ , Gd ₂ O ₃ , Nb ₂ O ₅ , ZrO ₂ , TiO ₂ , WO _{3 and the} like in a total amount of 0 to 40%. , Preferably 0.1 to 20%, more preferably 1 to 10%.

The glass material of the present invention can contain Sb ₂ O ₃ as a fining agent. However, in order to avoid coloring or in consideration of environmental aspects, the content of Sb ₂ O ₃ is preferably 0.1% or less, and more preferably not contained.

R ₂ O (R is at least one selected from Li, Na and K) has an effect of lowering the melting temperature, but its chemical durability is lowered, so its content is 10% or less. Preferably, it is preferably 5% or less, more preferably 3% or less, and particularly preferably not contained.

PbO, CdO and As ₂ O ₃ are preferably not contained from the viewpoint of the environment.

  The crack resistance of the glass material of the present invention is 3N or more, preferably 10N or more, more preferably 15N or more, and further preferably 20N or more. If the crack resistance is too small, for example, when used as a cover member of a medical treatment instrument, damage during use tends to occur.

  The glass material of the present invention is excellent in chemical durability. Specifically, it is preferable that no alteration is observed on the surface of the glass material by a pressure cooker test (133 ° C., 100% Rh, 250 hours).

In a glass material containing Al ₂ O ₃ and SiO ₂ as main components, particularly when a large amount of Al ₂ O ₃ is contained, the tendency to crystallize is strong and vitrification tends to be difficult. This is because the glass material is generally produced by melting the raw material in a melting container such as a crucible and cooling, so that the precipitation of crystals tends to proceed from the contact interface between the molten glass and the melting container. It is.

  The glass material of the present invention includes a composition that is difficult to vitrify as described above, but even in such a case, vitrification is possible by eliminating contact at the interface with the melting vessel. As such a method, a containerless floating method in which a raw material is melted and cooled in a suspended state is known. When this method is used, since the molten glass hardly comes into contact with the melting vessel, it is possible to prevent the precipitation of crystals starting from the interface with the melting vessel, and vitrification becomes possible. Thereby, it becomes easy to obtain a glass material with a large particle size easily. Specifically, a glass material having a particle size of 0.1 mm or more, preferably 0.6 mm or more, more preferably 1 mm or more, and further preferably 2 mm or more can be produced. In addition, the particle size of a glass material points out a long diameter, when shapes are other than spherical shape (ellipsoid etc.).

  FIG. 1 is a schematic cross-sectional view of a manufacturing apparatus for producing a glass material by a containerless floating method. Hereinafter, based on FIG. 1, the manufacturing apparatus of a glass material is demonstrated.

  The glass material manufacturing apparatus 1 includes a mold 10. The mold 10 also serves as a melting container. The molding die 10 has a molding surface 10a and a gas ejection hole 10b that is open to the molding surface 10a. The gas ejection hole 10b is connected to a gas supply mechanism 11 such as a gas cylinder. Gas is supplied from the gas supply mechanism 11 to the molding surface 10a via the gas ejection hole 10b. The type of gas is not particularly limited, and may be air or oxygen, or an inert gas such as nitrogen gas, argon gas, or helium gas.

  When manufacturing a glass material using the manufacturing apparatus 1, first, the glass raw material lump 12 is arrange | positioned on the molding surface 10a. As the glass raw material block 12, for example, a raw material powder integrated by press molding or the like, a sintered body obtained by integrating the raw material powder by press molding or the like, and a composition equivalent to the target glass composition are used. For example, an aggregate of crystals.

It is preferable to precipitate crystals composed of reaction products of constituent components during sintering of the raw material powder. By doing in this way, it becomes possible to suppress evaporation of a component in the melting process of the glass raw material lump 12. For example, by causing SiO ₂ and Al ₂ O ₃ to react by sintering raw material powder and precipitating mullite, it is possible to particularly suppress the evaporation of SiO ₂ in the melting step of the glass raw material block 12. In addition, the raw material powder may be once melted in a melting container and then cooled to precipitate crystals composed of reaction products of the constituent components.

  Next, the glass raw material block 12 is floated on the molding surface 10a by ejecting gas from the gas ejection holes 10b. That is, the glass raw material block 12 is held in a state where it is not in contact with the molding surface 10a. In this state, the glass material block 12 is irradiated with laser light from the laser light irradiation device 13. Thereby, the glass raw material lump 12 is heated and melted to be vitrified to obtain molten glass. Thereafter, the glass material can be obtained by cooling the molten glass. In the step of heating and melting the glass raw material mass 12 and the step of cooling until the temperature of the molten glass and further the glass material is at least the softening point or less, preferably the glass transition point or less, at least the gas ejection is continued, It is preferable to suppress contact between the glass raw material lump 12, molten glass, and further the glass material and the molding surface 10a. In addition to the method of irradiating with laser light, the method of heating and melting may be radiant heating.

  FIG. 2 is a schematic cross-sectional view showing another embodiment of a manufacturing apparatus for producing a glass material by a containerless floating method. The glass material manufacturing apparatus 1a shown in FIG. 2 differs from the glass material manufacturing apparatus 1 shown in FIG. 1 in that a plurality of gas ejection holes 10b are opened on the molding surface 10a. Specifically, as shown in FIG. 3, the plurality of gas ejection holes 10b are arranged radially from the center of the molding surface 10a. By providing a plurality of gas ejection holes 10b on the molding surface 10a as in the present embodiment, the floating state of the glass raw material block 12 is further stabilized and it becomes difficult to contact the molding surface 10a during melting. Therefore, crystallization of the glass material during melting or molding is further suppressed, and a glass material having a larger particle size can be obtained.

  The glass material produced by the above method is preferably processed into a desired shape (for example, a plate shape or a lens shape) by cutting or polishing as necessary.

  Since the glass material of the present invention is excellent in mechanical strength and chemical durability, it is suitable for a cover member of a medical treatment instrument such as an endoscope. FIG. 4 is a schematic perspective view showing an embodiment of an endoscope cover member made of the glass material of the present invention. The cover member 21 is made of a disk-shaped plate. The shape of the cover member 21 is not particularly limited, and may be a plate-like body such as a rectangular shape. Alternatively, the cover member 21 may have a lens shape, and in that case, the cover member 21 has both a function as a cover member that protects the distal end portion of the endoscope and a function as an optical lens.

  FIG. 5 is a schematic cross-sectional view showing an example in which the cover member 21 is attached to the distal end portion 22 a of the endoscope 22. As shown in FIG. 5, the cover member 21 is mounted so as to protect the distal end portion 22 a of the endoscope 22. The method of attaching the cover member 21 is not particularly limited, and examples thereof include a method of adhering to the distal end portion 22a of the endoscope 22 with glass frit, solder, or the like. The distal end portion 22a of the endoscope 22 may be formed with an opening for inserting the treatment instrument and an opening for flowing gas or liquid. In that case, the cover member 21 is also provided with an opening so as to correspond to the position of the opening.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples.

Example 1
Raw material powders were weighed and mixed so as to have a glass composition of 60% Al ₂ O _{3 and} 40% SiO _{2 in} mol% to prepare a raw material batch. The raw material batch was heat-treated at a temperature of 1050 ° C. and sintered to obtain a glass raw material lump.

  Next, using a manufacturing apparatus according to FIG. 1, with the glass raw material lump floated above the molding surface, a carbon dioxide laser with an output of 100 W is irradiated, and the glass raw material lump is heated to 1800 to 2000 ° C. to be melted. It was. Then, laser irradiation was stopped and the molten glass was cooled. As a result, a substantially spherical glass material having a particle size of 2.0 mm was obtained. It was 48.6N when the crack resistance of the obtained glass material was measured.

  Crack resistance was measured as follows. Number of cracks generated from the four corners of the indentation when a Vickers indenter set to a desired load is driven into the optically polished glass material surface for 15 seconds in a constant temperature and humidity chamber maintained at a humidity of 60% and a temperature of 25 ° C. Count (up to 4 per indentation). In this manner, the indenter driving test was performed 30 times at each load, and the crack occurrence rate was calculated by the following formula. The load at which the crack occurrence rate was 50% was defined as crack resistance. FIG. 6 is a graph showing the crack occurrence rate at each load.

  Crack generation rate = (total number of cracks generated / 4 × 30) × 100 (%)

  Further, a pressure cooker test (133 ° C., 100% Rh, 250 hours) was performed on the obtained glass material. When the surface of the glass material was observed after the test, no alteration was observed.

(Example 2)
A glass material was produced in the same manner as in Example 1 except that a manufacturing apparatus (gas ejection hole diameter: 0.3 mm) according to FIG. 2 was used. As a result, a substantially spherical glass material having a particle diameter of 4.5 mm was obtained. It was 48.8N when the crack resistance of the obtained glass material was measured.

  Moreover, when the pressure cooker test was done with respect to the obtained glass material, the quality change was not recognized by the glass material surface.

(Example 3)
A glass material was produced in the same manner as in Example 1 except that the raw material batch was prepared so as to have a glass composition of 55% Al ₂ O _{3 and} 45% SiO _{2 in} mol%. As a result, a substantially spherical glass material having a particle size of 1.9 mm was obtained. It was 19.7N when the crack resistance of the obtained glass material was measured.

  Moreover, when the pressure cooker test was done with respect to the obtained glass material, the quality change was not recognized by the glass material surface.

Example 4
A glass material was prepared in the same manner as in Example 1 except that the raw material batch was prepared so as to have a glass composition of 50% Al ₂ O _{3 and} 50% SiO _{2 in} mol%. As a result, a substantially spherical glass material having a particle diameter of 2.1 mm was obtained. It was 14.0 N when the crack resistance of the obtained glass material was measured.

  Moreover, when the pressure cooker test was done with respect to the obtained glass material, the quality change was not recognized by the glass material surface.

(Example 5)
A glass material was prepared in the same manner as in Example 1 except that the raw material batch was prepared so as to have a glass composition of 45% Al ₂ O _{3 and} 55% SiO _{2 in} mol%. As a result, a substantially spherical glass material having a particle size of 2.2 mm was obtained. It was 9.9 N when the crack resistance of the obtained glass material was measured.

  Moreover, when the pressure cooker test was done with respect to the obtained glass material, the quality change was not recognized by the glass material surface.

(Comparative example)
A glass material was produced in the same manner as in Example 1 except that the raw material batch was prepared so as to have a glass composition of 25% Al ₂ O _{3 and} 75% SiO _{2 in} mol%. As a result, a substantially spherical glass material having a particle size of 2.2 mm was obtained. It was 2.5N when the crack resistance of the obtained glass material was measured.

  The glass material of the present invention is suitable for a cover member of a medical treatment instrument such as an endoscope. Moreover, the glass material of the present invention can also be used as an optical element such as an optical lens.

1, 1a: Glass material manufacturing apparatus 10: Mold 10a: Molding surface 10b: Gas ejection hole 11: Gas supply mechanism 12: Glass raw material block 13: Laser beam irradiation device 21: Cover member 22: Endoscope 22a: Tip Part

Claims (5)

In mol%, Al ₂ O ₃ 45-80 %, SiO ₂ 20-55% and R ₂ O (R is at least one selected from Li, Na and K) 10% or less, and crack resistance is 3N A method for producing a glass material that is the above ,
By sintering a raw material powder containing SiO ₂ and _Al 2 _{O 3,} by reacting SiO ₂ and _Al 2 _{O 3,} and obtaining the material mass mullite precipitated,
A process of obtaining a glass material by cooling the molten glass after obtaining the molten glass by heating and melting the raw material lump in a state where the raw material lump is suspended and held above the molding surface of the mold , and
A method for producing a glass material, comprising: The glass material is, in _mole%, the production method of the glass material according to claim 1 in which the content of Al ₂ O 3 + SiO ₂ is equal to or less than 70%. The method for producing a glass material according to claim 1 or 2, wherein the glass material has a particle size of 0.1 mm or more. The said glass material is used as a cover member of a medical treatment instrument, The manufacturing method of the glass material as described in any one of Claims 1-3 characterized by the above-mentioned. The said glass material is used as an optical lens , The manufacturing method of the glass material as described in any one of Claims 1-3 characterized by the above-mentioned.