JP2004284893A - Molding die for hot press, method of manufacturing silica glass using the same, and silica glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding die for hot press capable of finely patterning or transferring and molding a material to be molded into a prescribed shape without biting the material to be molded by the shrinkage of the molding die, a method of manufacturing silica glass using the same, and a silica glass. <P>SOLUTION: In the molding die for hot press, a die of one side is composed of divided dies divided to plural numbers which are integrally held by engaging a tapered projected engaging part provided on the outer circumference of each divided die with a tapered recessed engaging part provided on a seat to which the die of one side is attached and is pressed with the material to be molded by a die of another side and the material to be molded is pressed by the side surface of the die of one side. The method of manufacturing silica glass using the same, and the silica glass formed by using the same are provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hot-press mold, a method for producing silica glass using the same, and a silica glass, and particularly relates to a hot-press mold that prevents biting of a molding material of a split mold, and a silica glass using the same. It relates to a production method and silica glass.
[0002]
[Prior art]
Heat press working is generally performed for forming a thermosoftening material. In that case, considering the releasability, the thermal expansion coefficient of the molding material and the molding die are made to match as much as possible, or it is considered that the thermal expansion coefficient of the molding die is smaller than that of the molding material. I have.
[0003]
However, when molding a material having a low coefficient of thermal expansion such as silica glass (also referred to as quartz glass) using such a conventional mold for hot press, it is difficult to obtain a suitable molding material. . For this reason, a measure is taken to form an angle on the wall surface of the transfer pattern and design the molding die so that the molding material shrinks at the time of cooling and does not bite the material to be molded, but moves in the direction of slipping and releasing. . However, in this method, the shape of the side surface of the mold cannot be maintained, and particularly, the wall surface which stands upright cannot be given to the material to be molded.
[0004]
That is, in consideration of the configuration of the hot press molding die 22 as shown in FIG. 9, when the thermal expansion coefficient of the lower die 23 is larger than the thermal expansion coefficient of the molding material M after the temperature rise, the lower die 23 contracts. There is a possibility that the molding material M cannot be released from the lower mold 23 by biting the molding material M, or the lower mold 23 may be damaged. Further, at the time of press molding, the pressure from the upper mold 24 escapes due to deformation toward the outer peripheral portion of the molding material M, so that there is a problem that a fine pattern is deformed or insufficient transfer occurs.
[0005]
In addition, in order to avoid biting, which is a problem in the conventional molding die shown in FIG. 9, the lower die 33 of the heating press molding die 32 is divided as shown in FIG. 33z has been proposed. However, the lower mold 33, which can avoid stress caused by cooling during contraction, pressurization of the aggressive the molded material M from the molded side 33a ₁ of the lower die 33 can not be expected, the splitting surface in the opposite A gap is generated between the lower split molds 33z due to the displacement, which has a problem that the shape of the molding material M is adversely affected.
[0006]
There is a glass mold in which a lower mold having a concave molding surface having a triangular cross section is divided into two, but this mold does not generate stress due to shrinkage during cooling, similarly to the latter conventional mold. Although it is possible, positive pressure from the molding side of the lower mold to the molding material cannot be expected, and conversely, a gap between the lower division molds due to the deviation of the division surface adversely affects the shape of the molding material. (For example, Patent Document 1 etc.).
[0007]
[Patent Document 1]
JP-A-6-9232 (paragraph number [0008], FIG. 1)
[0008]
[Problems to be solved by the invention]
The present invention has been made in consideration of the above circumstances, and does not bite a molding object due to shrinkage of a molding die, can perform a fine pattern or transfer, and can heat a molding material into a desired shape. An object of the present invention is to provide a press mold, a method for producing silica glass using the same, and silica glass.
[0009]
[Means for Solving the Problems]
According to one aspect of the present invention, there is provided a hot-press mold used for press-molding a heated and softened material, the concave being formed by forming the mold. One of the molds on which the molding surface is formed is a divided mold that is divided into a plurality of parts, and a tapered convex fitting portion provided on the outer periphery of the divided mold is provided on a base to which one of the molds is attached. Are held together by fitting into the concave fitting portion of the mold, and one of the molds constituting the molding die presses one of the molds via a molding material, and is covered by the molding side surface of the concave molding surface. There is provided a mold for heating press, characterized by pressing a molding material. Accordingly, a molding die for heating press, which can perform a fine pattern and transfer without causing the molding object to bite due to shrinkage of the molding die and can mold the molding material into a desired shape is realized.
[0010]
In a preferred example, the molding die is formed of a material that does not easily react with the molding material. This eliminates the need for a release film on the surface of the mold.
[0011]
In another preferred example, the one mold is divided along a surface in the same direction as a molding side surface. Accordingly, the molding material does not bite due to the contraction of one of the dies, and the force applied to the one of the dies easily generates a component force that attracts the molding side surfaces in a direction of approaching each other.
[0012]
In another preferred example, the tapered convex fitting portion and the tapered concave fitting portion have a conical shape or a pyramid shape. This makes it possible to reliably generate, from the force applied to one of the dies, a component force that attracts the molding side surfaces in a direction of approaching each other.
[0013]
In another preferred example, the distribution of the force applied to the molding side surface and the molding main surface of the concave molding surface can be adjusted by changing the depth of the tapered concave fitting portion.
[0014]
In another preferred example, a member that does not easily react with the material to be molded is attached to at least the main molding surface of the concave molding surface. Thereby, when it can be attached to the entire surface of the concave molding surface, by replacing the hard-to-react member, it is possible to eliminate the exchange due to the deterioration of the lower mold, reduce the molding cost, and attach only to the main molding surface. In this case, the step of the split type split surface is further reduced.
[0015]
Further, according to another aspect of the present invention, there is provided a method for producing silica glass, which is molded using the mold according to any one of claims 1 to 6. Thereby, a fine pattern or transfer can be performed without the object to be bitten by the shrinkage of the molding die, and the material to be molded can be molded into a desired shape.
[0016]
According to another aspect of the present invention, there is provided a silica glass having a precision pattern transferred thereto using the mold according to any one of claims 1 to 7. This makes it possible to easily obtain a silica glass on which a precise pattern is transferred.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of a hot press mold according to the present invention will be described with reference to the accompanying drawings.
[0018]
FIG. 1 is a conceptual diagram of a molding apparatus incorporating a first embodiment of a heating press molding die according to the present invention.
[0019]
As shown in FIG. 1, a molding die 1 for a press according to the present invention is incorporated in a molding device 1. The press forming die 2 according to the present invention includes a lower die 3 having a square plate-shaped concave forming surface 3a formed therein, and a molding material, for example, silica glass M, housed in the concave forming surface 3a. It is constituted by an upper mold 4 as the other mold having a square shape and a columnar shape in plan view, which presses and enters the concave molding surface 3a.
[0020]
The lower mold 3 is made of a material that is not easily reacted with glass having a low coefficient of thermal expansion at a high temperature, such as glassy carbon, molybdenum, tungsten, and ultra-hard, as a material to be molded, which is a thermosoftening material. When silica glass is used as the material to be molded, glassy carbon is preferable.For that reason, glassy carbon is formed by molding a thermosetting resin such as full free alcohol, and then gradually heated under pressure, It is manufactured by carbonization after curing, has a non-oriented structure, and has high heat resistance, high corrosion resistance, high strength, and high hardness. In addition, glassy carbon is different from a general mold material in that it has excellent mold releasability between glass and eliminates the need for a mold release film on the surface of the mold.
[0021]
The shape of the lower mold 3, without a tapered shape that decreases sequentially sectional area, and a lower die main portion 3b of the disk-shaped concave molding surface 3a is formed consisting of the molded side 3a ₁ and the molding main surface 3a ₂ And a conical or polygonal pyramid-shaped convex fitting portion 3c protruding from the lower die main portion 3b. The aforementioned molding main surface 3a _2, for example, FIG. 2 (a), is formed convex portions having a top portion as shown in (b).
[0022]
Further, as shown in FIGS. 3 and 4, the lower mold 3 is equally divided into four by the lower split mold 3 z on a surface (vertical surface) in the same direction as the molding side surface 3 a _1, and each has a fan shape in a plan view. As shown in FIG. 1, during use, the convex fitting portion 3 c of the lower mold 3 is fitted into a conical or polygonal pyramid concave fitting portion 5 a provided on the pedestal 5 and is integrally held. ing. Thus, the material to be molded can be pressed evenly from all sides, and the pressure from the mold 2 is considered to be evenly distributed to the plate-like material to be molded. By changing the depth of the concave fitting portion of the cone or polygonal pyramid, the pressure distribution between the forming side surface and the forming main surface with respect to the pressing pressure is appropriately adjusted.
[0023]
Further, the pedestal 5 is fixed on a fixed shaft 6.
[0024]
Like the lower die 3, the upper die 4 is made of glassy carbon or the like as a material that hardly reacts with the material to be molded, and is attached to the moving shaft 7 that moves up and down by hydraulic means (not shown). The press mold 2 is heated at the time of use by a heating means such as a lamp unit 8.
[0025]
Next, a forming method using the first embodiment of the hot press forming die according to the present invention will be described.
[0026]
As shown in FIG. 1, the convex fitting portion 3c of the lower mold 3 is fitted into the concave fitting portion 5a of the pedestal 5, the lower split mold 3z is integrally held, and the lower mold 3 is formed. The lower mold 3 and the upper mold 4 are heated in advance.
[0027]
The preheated concave mold surface 3a of the lower mold 3 accommodates the softened silica glass M, lowers the moving shaft 7, lowers the upper mold 4, and presses the silica glass M.
[0028]
Thereby, the silica glass M is formed along the shapes of the lower mold 3 and the upper mold 4.
[0029]
As shown in FIGS. 1 and 5, at this time, the force f applied to the component between the moving shaft 7 and the fixed shaft 6 due to the lowering of the moving shaft 7 is equal to the convex fitting portion 3 c of the lower mold 3 and the pedestal 5. the contact surface of the recessed fitting portion 5a, is decomposed into vertical component force f _v parallel component force f _h to the contact surface, the component force f _h, to approach the forming side 3a ₁ between the lower split 3z force is applied in the direction, as a result, the molded side 3a ₁ of the lower split mold 3z are pressed positively into the side surface of the molded material M. At the same time, the split surfaces of the lower split mold 3z are in close contact with each other, and the influence on the shape change of the molding material M can be reduced. The silica glass M is formed along the shapes of the lower mold 3 and the upper mold 4.
[0030]
Also, the lower mold 3, in terms of the forming side surface 3a ₁ and the same direction, because it is equally divided into four lower split 3z, without biting of the molded material M is generated by the contraction of the lower mold 3 further, the force f applied to the lower mold 3 is likely to generate component force f _h attract a direction to approach the forming side 3a ₁ together. Further, since the convex fitting portion 3c of the lower die 3 and the concave fitting portion 5a of the pedestal 5 are formed in a conical or pyramid shape, the molding side surfaces 3a ₁ are separated from each other by the force f applied to the lower die 3. it is possible to reliably generate the component force f _h attract the direction to close.
[0031]
Further, even when the coefficient of thermal expansion of the molding die cannot be made equal to or smaller than that of the molding material in the molding process, the molding material attempts to spread in the horizontal direction by the force f, and as a result, the lower mold of the press molding die is formed. 3 overcomes it even if a force to widen in the horizontal direction, the component force f _h, attracts a direction to approach the forming side 3a ₁ together, suppressing deformation of the peripheral portion of the molded material The press mold enables the molding of the side wall of the material to be molded, and the pressure can be reliably applied to the entire surface of the mold. If a transfer pattern is formed on the press mold, stamping and special The transfer accuracy of the shape can be improved, and precise molding can be performed at every corner of the object. Further, even when there is a possibility that the molding material may be caught by the difference in the thermal expansion coefficient between the molding die and the molding material, the press working can be performed with high accuracy while controlling the side surface shape.
[0032]
Further, a second embodiment of the hot press molding die according to the present invention will be described.
[0033]
In the second embodiment, the first embodiment uses a material that does not easily react with the molding material for the entire lower mold, whereas a material that does not easily react with the molding material is used in a portion that contacts the molding material. Is what you use.
[0034]
For example, as shown in FIG. 6, the press mold 2A according to the second embodiment is composed of a common metal lower mold 3A and an upper mold 4A, and the concave mold surface 3Aa of the lower mold 3A has glassy carbon made of molded plate 11A, glassy carbon-made mold side plates 12A which are attached to the forming side surface 3Aa ₁ as a reaction difficult material as the molded material in the laid plate to the molded main surface 3Aa ₂ Is provided. The other configuration is not different from the hot press molding die shown in FIG.
[0035]
This way, since the glassy carbon made of molded plate 11A is provided in the molding main surface 3Aa ₂ of at least the concave molding surface 3Aa, it is possible to further reduce the step difference of the divided surface of the lower split mold 3AZ, also be By using a glass-like carbon only for a portion that is in contact with the molding material and having a replaceable configuration, replacement due to deterioration of the lower mold can be eliminated, and molding cost can be reduced.
[0036]
As described above, the use of the heating press mold of the present invention makes it possible to easily form silica glass, and to obtain a silica glass in which a precise pattern such as an uneven pattern of 500 μm or less is transferred to the surface. Can also be easily done.
[0037]
Of course, an uneven pattern of 1 μm or less can be transferred with higher accuracy.
[0038]
【Example】
A □ 40 mm, 3 mm thick glassy carbon plate with a pattern of V protrusions having a height of 100 μm and a width of 200 μm as shown in FIG. 2 is used as a lower mold, and a quartz (silica glass) plate of □ 40 mm, 2 mm thick is formed. Pressing was carried out in the form shown in FIG. 6 by surrounding the four sides and the upper mold with a mirror-like polished plate of glassy carbon. At that time, the temperature of the lower mold and the upper mold was 1450 ° C., the pressure was 2.5 kN, and the pressure time was 80 seconds. As a comparative example, a glass-like carbon mirror-polished plate for restraining one set of side walls facing each other was pressed under the same conditions in a deformable state, and the transfer in FIG. Gender. The press started pressurizing after the temperature was stabilized, completely removed the pressure applied after the pressurization was completed, and then started lowering the temperature. This is because the lower mold with pattern may be damaged if pressed before the quartz is sufficiently softened, and the difference in thermal expansion coefficient between quartz and glassy carbon when the temperature is reduced while applying pressure. This is because the generated stress cannot be reduced by the effect of the present invention. As a result of the above pressing, non-transfer area on the foot of the V-projection as shown in FIG. 8, as shown in FIG. 7 (b), (c) , non-transfer area _U 3 ~U ₄ and _U 5, U Compared to the case where ₀ was not constrained by the side wall (U ₁ , U ₂ in FIG. 7A), it was found that when 0 was constrained by the mold shown in FIG. From this, it was confirmed that the transferability was significantly improved by the side wall constraint in the present invention. In addition, even when the above-mentioned press was performed, neither quartz nor glassy carbon mold was damaged. Compared with the V-shaped protrusion, the transferability of the press according to the present method is still weak, but this is due to the effect of air accumulation due to the nitrogen atmosphere, and the process is performed in a vacuum as shown in FIG. example, if it non-transfer area U ₅ and U ₆ is to be also clearly shown improvement since hardly recognized know from experiments.
[0039]
The present invention is not limited to the above embodiment. For example, in FIG. 3, the lower division type 3z is divided into four parts, but the setting is easier with two divisions. Further, the division is performed by a straight line in the diagonal direction, but may be a curve or the like.
[0040]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the molding die for a heat press according to the present invention, a fine pattern or transfer is possible without biting the molding object due to shrinkage of the molding die, and the molding material for a heating press can be molded into a desired shape. A mold can be provided.
[0041]
Further, according to the method for producing silica glass according to the present invention, a fine pattern or transfer is possible without biting a molding object due to shrinkage of a molding die, and silica capable of molding a molding material into a desired shape. A method for producing glass can be provided.
[0042]
Further, according to the silica glass according to the present invention, it is possible to provide a silica glass in which a precise pattern is easily transferred.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a use state of a first embodiment of a hot press molding die according to the present invention.
FIG. 2 (a) is a plan view of a molding main surface of a lower mold of a first embodiment of a molding die for a heat press according to the present invention, and FIG. 2 (b) is a sectional view thereof.
FIG. 3 is a plan view of a lower mold according to the first embodiment of the heating press forming mold according to the present invention.
FIG. 4 is a side view of a lower split mold constituting the lower mold of FIG. 3;
FIG. 5 is an explanatory view showing a state of a force when the molding die for a hot press according to the present invention is used.
FIG. 6 is a conceptual diagram showing a use state of a second embodiment of a hot press molding die according to the present invention.
FIGS. 7A and 7B show test results using a hot-press mold and a comparative example according to the present invention, wherein FIG. 7A shows a comparative example, FIG. 7B shows one example, and FIG. 7C shows another example. .
FIG. 8 is a conceptual diagram of an untransferred region generated in a comparative example in a molding test.
FIG. 9 is a conceptual diagram showing a use state of a conventional hot press forming die.
FIG. 10 is a conceptual diagram showing a use state of a conventional hot press molding die.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Molding apparatus 2 Press molding die 3 Lower mold 3a Concave molding surface 3a ₁ Molding side 3a ₂ Molding main surface 3b Lower mold main part 3c Convex fitting part 3z Lower split mold 4 Upper mold 5 Base 5a Concave fitting part 6 Fixed axis 7 Moving axis 8 Lamp unit M Silica glass U _{1 to} U ₆ Untransferred area

Claims (8)

A heating press mold used to press-mold a heated and softened molding material. One of the molds that forms the mold and has a concave molding surface is divided into a plurality of divided molds. A mold, and the tapered convex fitting portion provided on the outer periphery of this split mold is integrally held by fitting into a tapered concave fitting portion provided on a pedestal to which one of the molds is attached, A molding die for heating press, wherein one of the dies forming the molding die presses one of the dies through a molding material, and the molding material is pressed by a molding side surface of the concave molding surface. The mold according to claim 1, wherein the mold is formed of a material that does not easily react with the material to be molded. The mold according to claim 1, wherein the one mold is divided by a surface in the same direction as a molding side surface. The mold according to any one of claims 1 to 3, wherein the tapered convex fitting portion and the tapered concave fitting portion have a conical shape or a pyramid shape. The method according to claim 1, wherein a distribution of a force applied to a molding side surface and a molding main surface of the concave molding surface is adjusted by changing a depth of the tapered concave fitting portion. Mold for heating press. The molding die for hot press according to claim 5, wherein a member that does not easily react with the molding material is attached to at least the molding main surface of the concave molding surface. A method for producing silica glass, which is molded using the molding die according to claim 1. A silica glass having a precision pattern transferred thereto using the mold according to claim 1.

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