JP2001105449A - Optical reflecting member made of thermoplastic resin and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical reflecting member made of a thermoplastic resin having an optical reflecting surface extremely excellent in mirror surface properties. SOLUTION: An optical reflecting member 10 has at least one optical reflecting surface 13 and a hollow part 14 is provided to the part (hollow part constituting part 11) of the optical reflecting member 10 constituting the whole area of the optical reflecting surface 13 by introducing a pressure fluid into the part 11. Since the shrinkage of the thermoplastic resin is suppressed at the time of molding, the optical reflecting member extremely excellent in mirror surface properties over the whole area of its optical reflecting surface can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical reflecting member made of a thermoplastic resin having an optical reflecting surface having extremely excellent mirror-like properties, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Optical scanning reflectors used in digital devices such as copiers and laser beam printers,
Conventionally, optical reflecting members such as reflecting mirrors for automobiles and motorcycles, represented by rearview mirrors and reflectors,
Although it has been manufactured using glass, the shift to thermoplastic resin is advancing from the viewpoint of cost reduction, weight reduction, and the degree of freedom in shape due to the improvement in required functionality.

For mechanical parts (mounting members) such as a carriage for a scanner, a change from a sheet metal or an aluminum die-cast product to a resin material has been studied for the purpose of weight reduction and productivity improvement. The performance required for the mechanical components such as the scanner carriage is mechanical characteristics, heat resistance, flame retardancy, dimensional stability, mirror angle accuracy (accuracy of the angle of the mirror mounting portion), productivity, and the like. Particularly severe performance is mirror angle accuracy and productivity. For example, when the mirror section angle accuracy cannot be maintained, functions such as data reading are impaired. Therefore, as an injection molding material for a mechanical component, a reinforced material containing an inorganic fiber or the like is used in order to improve rigidity and dimensional accuracy of the mechanical component. Usually, a reflecting mirror is attached or fitted to the mechanical component.

Generally, as a method of manufacturing a molded article made of a thermoplastic resin, a mold having a cavity is used.
An injection molding method has been used in which a molten thermoplastic resin is injected and filled into a cavity of a mold maintained at a constant temperature, and the thermoplastic resin in the cavity is cooled and solidified. However, such as an optical reflection member, (1) a thick molded product, (2) a molded product having an uneven thickness portion, or (3)
In the case of molding a long molded product, (1) and (2) correspond to the portion between the thick portion and the thin portion of the molded product, and (3) corresponds to the center portion and the end portion. As a result, there is a difference in the cooling rate of the molten thermoplastic resin in the cavity, and as a result, distortion tends to occur in the molded product. Therefore,
There is a problem that it is difficult to transfer the mold surface of the cavity having high mirror finish to the molded product with high accuracy, that is, it is difficult to enhance the mirror transfer accuracy.

[0005] In order to improve the mirror transfer accuracy in this type of molded article molding method, for example, the following measures have been conventionally adopted.

Injection compression molding method Glass transition temperature T of thermoplastic resin_gOver heated
Injection and filling of molten thermoplastic resin into the cavity of the mold
After sealing, the gate is sealed and the
Gradually cool the thermoplastic resin in the
Pressure is 0kg / cm ^Two-Take out the molded product when it becomes G
Molding method (see Japanese Patent Application Laid-Open No. 64-38421) A resin base material pre-processed to almost the final shape is formed by another mold.
Glass transition temperature T of base resin_gHeat again and heat
Molding method of gradually cooling to below the forming temperature
No. 19) Materials of two opposite mold surfaces provided in the cavity
Change the quality and surface roughness and melt the thermoplastic inside the cavity
Immediately before filling completely with the thermoplastic resin, the molten thermoplastic resin
Finish injection into the cavity and apply the pressure without applying pressure.
By cooling and solidifying the thermoplastic resin in the cavity
Mold surface on which the optical reflecting surface of the optical reflecting member is to be formed.
Adhesion to thermoplastic resin is higher than that of the other mold
(Japanese Patent Publication No. Hei 6-98642 and Japanese Patent Laid-Open No.
No. 51218) A mold for forming an optical reflecting surface of an optical reflecting member.
Keep the mold surface of the tee above the thermal deformation temperature of the thermoplastic resin
While cooling other mold surfaces,
Molding method for generating resin sink marks intensively on other mold surfaces
(Refer to JSME '94 Proceedings P237-P240)

[0007]

However, in the above method, it is difficult to obtain sufficient mirror-like transfer accuracy depending on the size of the shape of the optical reflecting member and the distribution of uneven thickness. In the methods (1) and (2), since the cooling is performed, the molding cycle is lengthened, and the productivity is reduced. In addition, in order to improve productivity, there are economical problems such as separate processes in which each of filling, slow cooling, and unloading processes can be continuously performed, and a need for a plurality of molds with high mirror surface accuracy. . In the method of (1), the adhesive force is reversed depending on the material of the mold portion constituting each mold surface (transfer surface and rough surface) of the cavity or the thermoplastic resin used, and the optical reflection surface of the optical reflection member is changed. Sinks occur in the portion of the thermoplastic resin that is in contact with the mold surface on which is to be formed. Further, when the timing of stopping the filling of the molten thermoplastic resin is shifted, the relationship between the adhesiveness between the molten thermoplastic resin and the mold surface is reversed, and the mold surface on which the optical reflecting surface of the optical reflecting member is to be formed. Sinking occurs in the portion of the thermoplastic resin that is in contact, or the amount of the molten thermoplastic resin to be filled in the cavity becomes insufficient. In the method of
There is a problem of stability such that the optical reflection member is warped due to a mold temperature difference.

On the other hand, in order to improve the dimensional accuracy of the molded product, a plurality of resin introduction portions are installed in a mold, and the pressure of the molten thermoplastic resin introduced into the cavity and the pressure for holding the pressure are made uniform. Molding method, extension of cooling time, etc.
There is a molding method for extending the restraint time of a molded article in a mold. However, in the former molding method, depending on a molded product, a plurality of resin introduction portions cannot be installed at a desired position due to restrictions on a shape, and a sufficient effect cannot be obtained in many cases. Further, in the latter molding method, the molded article restraining time is extended, so that the molding cycle becomes longer and there is a problem in productivity.

The above-described method of forming an optical reflection member is a method of forming when using a non-reinforced material.
When a reinforcing material containing an inorganic fiber is used in order to satisfy the physical properties required for the optical reflecting member (for example, mechanical performance and mirror angle accuracy), the inorganic fiber There is a problem in that the appearance is poor due to the precipitation, or the specularity is impaired. Therefore, it is very difficult to integrate the optical reflection member and the holding portion (mechanical component) that holds the optical reflection member.

Accordingly, a first object of the present invention is to provide an optical reflecting member made of a thermoplastic resin having an optical reflecting surface with extremely excellent mirror finish, and to manufacture such an optical reflecting member with a relatively small amount. It is an object of the present invention to provide a method of manufacturing an optical reflecting member which enables economical and stable manufacturing in a process. A second object of the present invention is to provide, in addition to the first object, an optical reflecting member capable of satisfying physical characteristics such as mechanical performance and mirror angle accuracy, and a method of manufacturing the same. .

[0011]

The optical reflecting member according to the present invention for achieving the first object has at least one optical reflecting surface, and constitutes the entire area of the optical reflecting surface. It is characterized in that a hollow portion formed by introducing a pressurized fluid is provided in a portion of the optical reflection member. Hereinafter, the portion of the optical reflecting member that forms the entire area of the optical reflecting surface may be referred to as a hollow portion forming portion for convenience.

A first object of the present invention is to provide a pressurized fluid in a portion (hollow portion constituting portion) of an optical reflecting member which has at least one optical reflecting surface and constitutes the whole area of the optical reflecting surface. What is claimed is: 1. A method of manufacturing an optical reflecting member made of a thermoplastic resin having a hollow portion formed by introducing a mold, the injection method comprising: providing a cavity having a mold surface for forming the optical reflecting surface. (A) using a molding die to inject a molten thermoplastic resin into the cavity;
A step of introducing a pressurized fluid into the molten thermoplastic resin in the cavity to form a hollow portion in a portion of the optical reflecting member (hollow portion constituting portion) constituting the entire area of the optical reflecting surface;
(C) a step of maintaining the pressure in the hollow portion within a desired pressure range until the thermoplastic resin in the cavity is solidified and cooled; and (d) removing the pressurized fluid in the hollow portion, and then removing the mold. Opening, and taking out the optical reflecting member. The method can be achieved by the method for producing an optical reflecting member according to the present invention.

In the optical reflecting member or the method of manufacturing the same according to the present invention, the hollow portion may extend to a portion of the optical reflecting member which does not constitute the entire area of the optical reflecting surface.

In the method for manufacturing an optical reflection member according to the present invention,
If nesting described later is not used, step (c)
Pressure range (all expressed by gauge pressure) is 1 × 1
0^FivePa (1kgf / cm^Two−G) to 5 × 10⁶Pa
(5 × 10kgf / cm^Two-G), more preferably
1.2 × 10^FivePa (1.2 kgf / cm^Two-G) to 4
× 10⁶Pa (4 × 10 kgf / cm^Two-G), more preferred
Or 2.0 × 10^FivePa (2.0 kgf / cm^Two−
G) to 2.5 × 10⁶Pa (2.5 × 10kgf / c
m^Two-G) is desirable. In addition, put
Using a thermoplastic resin containing inorganic fibers
When used, the desired pressure range in step (c) is
1 × 10^FivePa (1kgf / cm^Two−G) to 3 × 10⁷
Pa (3 × 10^Twokgf / cm^Two-G), more preferred
Is 1 × 10^FivePa (1kgf / cm^Two−G) to 2 × 1
0⁷Pa (2 × 10^Twokgf / cm^Two-G), more preferred
H, 1 × 10^FivePa (1kgf / cm^Two−G) to 1 ×
10⁷Pa (1 × 10^Twokgf / cm ^Two-G)
Is desirable. Use thermoplastic resin containing inorganic fiber
If the pressure range is not raised to some extent,
There is a possibility that a hollow portion is not formed. Inside hollow part
When a void is formed, the heat in the hollow component
The contraction of the plastic is formed by the introduction of pressurized fluid
If the inside of the hollow part is maintained at a pressure sufficient to
The desired pressure at this level of relatively low pressure is sufficient
What is necessary is just to hold the pressure in a hollow part in the range. Desired pressure range
1 × 10^FiveIf Pa or more, hollow in the hollow component
The part can be reliably formed. While using nesting
If not, set the desired pressure range to 5 × 10⁶Pa or less
In this way, the mold surface for forming the optical reflection surface
Press the molten thermoplastic resin in the cavity from the hollow
Pressure exceeds the pressure responsible for shrinking the thermoplastic resin
Overpressure is low and the optical reflection member
It is hard to generate residual stress, and it is an optical reflection member from the mold.
Release is not a problem. As a result of the above,
It may damage the specularity of the optical reflection surface of the optical reflection member.
Less.

In the method for manufacturing an optical reflecting member of the present invention, the desired pressure range in the step (c) is adjusted by applying a pressure in the hollow portion until the thermoplastic resin in the cavity is solidified and cooled. It may be controlled by the pressure of the pressurized fluid, may be controlled by the volume of the pressurized fluid introduced in the step (B) (b), or (C) the mold may further include a movable core, May be controlled by the position control. In the method (C), specifically, the volume of the optical reflecting member and further the volume of the hollow portion are increased by the movement of the movable core.

In the optical reflection member of the present invention or the optical reflection member obtained by the method of manufacturing the same, an injection molding die provided with a cavity having a die surface for forming an optical reflection surface. The optical reflection member is manufactured using the optical reflection member between the optical reflection surface of the optical reflection member molded in the cavity and the mold surface for forming the optical reflection surface. Preferably, there is only a gap of 1 μm or less per 10 mm ^{2 of} surface.

The optical reflection member of the present invention or the optical reflection member obtained by the method for producing the same has a solid portion extending from the hollow portion, and the surface of the solid portion is optically reflective. A configuration that does not constitute a surface can be adopted. still,
The solid portion may extend from a portion of the optical reflection member that extends from the hollow portion configuration portion and has the hollow portion but does not configure the optical reflection surface. Note that the holding portion may be formed from a portion of the optical reflecting member having the hollow portion but not forming the optical reflecting surface. In the optical reflecting member having these configurations, the volume occupied by the solid portion is 1 to 60%, preferably 5 to 60%, more preferably 5 to 30%, and still more preferably the volume of the optical reflecting member. 5-25%,
More preferably, it is desirable to be 5 to 15%.
Further, in the optical reflecting member having such a configuration or a method for manufacturing the same, the optical reflecting member is formed by using an injection molding mold provided with a cavity having a mold surface for forming an optical reflecting surface. Is manufactured, the molten thermoplastic resin injected into the cavity during the production of the optical reflection member,
It flows from the hollow part toward the solid part. When the optical reflecting member does not have such a solid portion, the hollow portion can be formed only in a part of the optical reflecting member constituting the optical reflecting surface depending on the structure of the mold. In some cases, the specularity of the optical reflection surface may be reduced. On the other hand, when the solid portion is not formed at all, depending on the structure of the mold, when the thermoplastic resin in the cavity is solidified, the pressure in the hollow portion is kept in a desired pressure range until it is cooled. In some cases, the pressure in the hollow portion cannot be maintained within a desired pressure range, and the specularity of the optical reflection surface may be reduced.

In order to achieve the second object, the optical reflecting member of the present invention has a holding portion for holding the optical reflecting surface, and the optical reflecting surface and the holding portion are integrated. It can also be configured. In the method for manufacturing an optical reflection member according to the present invention, in order to achieve the second object, the optical reflection member has a holding portion for holding the optical reflection surface, It is also possible to adopt a configuration in which the holding part is integrally formed. In these cases, the holding portion is preferably solid. It is preferable that the angle accuracy of the optical reflection surface with respect to the holding portion is set to ± 0.5 ° or less of the design angle.

Alternatively, in the optical reflecting member of the present invention including a structure having a holding portion, an injection mold having a cavity having a mold surface for forming an optical reflecting surface is used. Then, an optical reflecting member is manufactured, and the mold surface may be formed of a glass or ceramic nest having a thickness of 0.5 mm or more and 10 mm or less. Further, in the method for manufacturing an optical reflecting member of the present invention including the holding portion, the mold surface for forming the optical reflecting surface is formed by a glass or ceramic nest having a thickness of 0.5 mm or more and 10 mm or less. It can be a structured structure. In these cases, the thermal conductivity of the nest is 8.5 J / (msK) or less [8.5 W
/ (M · K) or less, or 2 × 10 ^-2 cal / (c
m · s · K) or less].

The material constituting the nest has a thermal conductivity of 8.5.
If it exceeds J / (ms · K), it becomes impossible to prevent rapid cooling of the molten thermoplastic resin injected into the cavity, and the specularity of the optical reflecting surface of the obtained optical reflecting member is reduced. May be. Glass nest broadly zirconia material, alumina-based materials, ceramics selected from the group consisting of K ₂ O-TiO _2, or selected from the group consisting of soda glass, quartz glass, heat resistant glass, a crystallized glass And more specifically, ZrO ₂ , ZrO ₂ —CaO, ZrO ₂ —Y ₂ O ₃ , Z
rO ₂ -CeO ₂ , ZrO ₂ -MgO, ZrO ₂ -Si
_{O 2, K 2 O-TiO} 2, Al 2 O 3, Al 2 O 3 -TiC,
_{Ti 3 N 2, 3Al 2 O} 3 -2SiO 2, MgO-SiO 2,
_{2MgO-SiO 2, MgO-Al} 2 O 3 -SiO 2 and the ceramic selected from the group consisting of titania, or soda glass, quartz glass, heat resistant glass, made of glass selected from the group consisting of crystallized glass And ZrO ₂ , ZrO ₂ —Y ₂ O ₃
Or from ZrO ₂ —CeO ₂ or, alternatively, from crystallized glass.

When the nest is made from crystallized glass,
The nesting has a crystallinity of 10% or more, more preferably a crystallinity of 60% or more, and still more preferably a crystallinity of 70 to 1%.
Preferably, it is made from 00% crystallized glass. 1
When the degree of crystallinity becomes 0% or more, the crystals are uniformly dispersed throughout the glass, so that the thermal shock strength and the interfacial peeling property are dramatically improved, so that the occurrence of nest breakage during molding of the optical reflecting member is significantly reduced. Can be done. When the degree of crystallinity is less than 10%, there is a drawback that interface separation easily occurs from the surface during molding. Preferably, the crystallized glass constituting the nest has a linear expansion coefficient of 1 × 10 ⁻⁶ / K or less and a thermal shock strength of 400 ° C. or more. When the nest is made of ceramic, a convex protrusion may be transferred to the surface of the optical reflecting member because the nest material is porous. However, crystallized glass has advantages in that the crystal particles are fine, the adhesion between the particles is excellent, and the surface of the optical reflecting member is easily mirror-finished because it is not porous.

The thermal shock strength is defined as a value obtained by heating a sample to a predetermined temperature.
When a glass of 00 mm x 100 mm x 3 mm is thrown into water at 25 ° C, the temperature at which the glass is cracked or not is defined as strength. Thermal shock strength is 4
100 ° C means 100 mm x heated to 400 ° C
When a glass of 100 mm × 3 mm is thrown into water at 25 ° C., it means that the glass does not crack.
The thermal shock strength of the heat-resistant glass is only about 180 ° C. Therefore, when the molten thermoplastic resin contacts the nest at higher temperatures (eg, about 300 ° C.), the nest may be distorted and the nest may be damaged. Thermal shock strength is also related to the crystallinity of glass,
If the nest is made from crystallized glass having a degree of crystallinity of 10% or more, it is possible to reliably prevent the nest from breaking during molding.

Here, the term “crystallized glass” refers to a small amount of raw glass.
Quantity of TiO_TwoAnd ZrO_Two1600 ° C
After melting under the above high temperature, press, blow, roll,
It is molded by a casting method, etc.
After the treatment, Li _TwoO-Al_TwoO_Three-SiO_Twosystem
A crystal is grown, and the main crystal phase is β-eucryptite
Of crystal and β-spodumene-based crystal grown
Can be Alternatively, CaO-Al_TwoO_Three-Si
O_TwoAfter melting the base glass at 1400-1500 ° C,
And then crushed to reduce the size of the particles.
After forming into a plate on a heater, heat treatment is further
It is possible to exemplify the generation of the lastonite crystal phase.
Wear. Furthermore, SiO_Two-B_TwoO_Three-Al_TwoO_Three-MgO-
K_TwoHeat treatment of OF-based glass to produce mica crystals
And MgO-Al containing nucleating agent_TwoO_Three-SiO_TwoSystem gala
Heat-treated to produce cordierite crystals
Can be exemplified. In addition, strength and
Β-eucryptite-based crystals or β-steels with excellent thermal properties
Use of crystallized glass having podumene-based crystals
preferable.

In these crystallized glasses, the ratio of crystal particles present in the glass substrate can be represented by an index called crystallinity. Then, the degree of crystallinity can be measured by measuring the ratio between the amorphous phase and the crystalline phase using an analytical instrument such as an X-ray diffractometer.

When the nest is made of amorphous glass such as soda glass, heat-resistant glass, quartz glass, etc., a thermoplastic resin (eg, polyamide 6 resin, polyamide 66 resin, polyamide) excellent in affinity and adhesion to these materials is used. MXD
6 resin or a polyester resin such as a PBT resin or a PET resin), the nest and the resin are firmly adhered to each other, and when the optical reflecting member is released from the mold, There is a case where a problem that the specularity is impaired occurs. In such a case, the nest may be made of crystallized glass.

When the nest is made of ceramic, at least one thin film layer made of the above-mentioned nesting material may be provided on the surface of the nest by a surface treatment technique such as ion plating. The holes can be filled, and the surface characteristics of the optical reflecting surface of the optical reflecting member can be further improved. However, the thickness is preferably 20 μm or less. If the thickness exceeds this, there is a possibility that the heat insulating effect is reduced and the adhesion of the thin film layer to the surface of the nest is reduced.

Alternatively, it is preferable that the coefficient of linear expansion of the material forming the nest is not more than 12 × 10 ⁻⁶ / deg. Here, the linear expansion coefficient is an average value at 50 ° C. to 300 ° C. Thus, the coefficient of linear expansion is 12 × 1
Be manufactured from 0 ^-6 / deg or less of ceramic or glass, it is possible to prevent the nesting of the deformation and breakage such mold and the nest by expansion and contraction of the different materials each other effectively. For example, when molding an optical reflecting member by mounting a nest on a mold (or core in some cases) made of carbon steel, the heat of the molten thermoplastic resin and the heat of water or oil etc. of the mold temperature controller are used. The mold and nest both expand thermally. If the coefficient of linear expansion exceeds the above value, the nest may be damaged due to the difference in the coefficient of linear expansion unless the clearance between the nest mounting portion provided on the mold and the nest is considerably increased. When the nest is made of crystallized glass, the coefficient of linear expansion can be 1 × 10 ⁻⁶ / deg or less.

It is desirable that the surface roughness _Ry of the nested cavity surface be 0.03 μm or less. Surface roughness R _y
Exceeds 0.03 μm, the specularity may be insufficient, and characteristics required for the optical reflecting surface, for example, image clarity may not be satisfied. For this purpose, for example, diamond lapping may be performed on the cavity surface of the prepared nest until the surface roughness _Ry becomes 0.03 μm or less, and lapping with cerium oxide may be performed as necessary. . Lapping can be performed using a lapping machine or the like. It is desirable that the wrapping be performed in the final step of the nesting process. Compared with the polishing of ordinary carbon steel or the like, for example, in the case of crystallized glass, a mirror surface can be obtained at a cost of about 1/2, so that the manufacturing cost of the mold assembly can be reduced. The measurement of the surface roughness R _y is based on JIS
B0601-1994.

After processing into a predetermined shape by grinding or the like, there is no danger that the nest will fall from the nest mounting portion provided inside the mold when the nest is mounted, and it will not be damaged. When the nest can be mounted on the nest mounting portion, the nest can be directly mounted on the nest mounting portion provided inside the mold without using an adhesive. Alternatively, the nest may be bonded to the nest mounting portion using a thermosetting adhesive selected from an epoxy-based, silicon-based, urethane-based, acrylic-based, or the like. However, it is desirable to make the thickness of the adhesive as thin and uniform as possible in order to prevent the nest from being distorted due to the uneven thickness of the adhesive. Note that the nesting core provided with the nesting portion may be attached to the mold portion, and the nesting portion may be attached to the nesting portion of the nesting core.

With respect to the material constituting the nest, it is possible to easily process irregularities, curved surfaces, and the like by ordinary grinding, and it is possible to manufacture a nest having any shape other than a considerably complicated shape. A nest can be produced by placing a ceramic powder or a molten glass in a molding die, press-molding and heat-treating. In addition, a nest can also be produced by forming a plate-like object made of glass on a jig and forming it naturally in a furnace. The lapping process can be easily performed in the final step.

If the runner portion and the gate portion are made from a ceramic material or a glass material constituting the nest,
Since the molten thermoplastic resin in the runner portion and the gate portion is not quenched, the gate portion sealing time can be extended, and even when using a thermoplastic resin containing inorganic fibers, a wide range of molding conditions is obtained. It is possible to set more appropriate conditions.

When nesting is used, a thermoplastic resin containing inorganic fibers can be used. It is preferable that the thermoplastic resin contains 5% to 60% by weight of inorganic fibers. In addition, the average length of the inorganic fiber is 5 μm
To 0.3 mm, more preferably 5 μm to 0.2 mm
It is desirable that In these cases, it is desirable that the average diameter of the inorganic fibers be 0.01 μm to 15 μm, more preferably 0.1 μm to 10 μm.

In the prior art, when a molded article is molded using a thermoplastic resin containing inorganic fibers, the appearance of the molded article deteriorates as a result of the inorganic fibers being deposited on the surface of the molded article, or The problem that the performance (specularity) is deteriorated is likely to occur. Therefore, it has been difficult to use a thermoplastic resin containing inorganic fibers for a molded article requiring excellent appearance characteristics and image clarity. In addition, the phenomenon of inorganic fiber precipitation on the surface of a molded article can be recognized by, for example, floating of the inorganic fiber on the surface of the molded article. Therefore, in order to solve the problem such as the precipitation of inorganic fibers on the surface of the molded article, in the conventional technology, it is necessary to reduce the viscosity of the thermoplastic resin and improve the fluidity of the molten thermoplastic resin. I was However, when the content of the inorganic fibers is increased, it is difficult to prevent the inorganic fibers from depositing on the surface of the molded article. For this reason, it has been difficult to use a thermoplastic resin containing inorganic fibers in a molded article requiring excellent appearance characteristics, despite having excellent performance. The reason why the inorganic fiber precipitates from the surface of the molded article when the content of the inorganic fiber increases is related to the material of the mold. Usually, the mold is made of a metal material having good thermal conductivity, so the molten thermoplastic resin containing the inorganic fibers introduced into the cavity is instantaneously cooled when it comes into contact with the cavity surface of the mold. start. As a result, a solidified layer is formed on the molten thermoplastic resin in contact with the cavity surface of the mold, and inorganic fibers are deposited. in addition,
There is a problem that the transferability of the cavity surface of the mold to the surface of the molded product is insufficient. When a nest with low thermal conductivity is used, a solidified layer is formed on the molten thermoplastic resin in contact with the cavity surface of the mold part because the molten thermoplastic resin introduced into the cavity is not quenched. Therefore, it is possible to reliably prevent the inorganic fibers from being precipitated. Further, since the molten thermoplastic resin in the resin injection portion is not rapidly cooled, the transferability of the surface constituting the cavity of the mold to the optical reflection surface can be further improved.

In this case, the ratio of the inorganic fibers contained in the thermoplastic resin (in other words, the ratio of the inorganic fibers added to the thermoplastic resin) is such that the physical properties required for the optical reflecting member can be satisfied. The upper limit is set as long as the fluidity of the molten thermoplastic resin in the cavity is reduced, so that molding becomes difficult, or an optical reflecting member having excellent specularity is formed. It may be a value when it becomes impossible. Specifically, when a crystalline thermoplastic resin is used, the upper limit is approximately 60% by weight. When an amorphous thermoplastic resin is used, its fluidity is inferior to that of a crystalline thermoplastic resin, and in some cases, the upper limit is approximately 50% by weight. If the content is less than 5% by weight, the physical properties required for the optical reflection member cannot be obtained, and if it exceeds 60% by weight, the fluidity of the molten thermoplastic resin is reduced, so that the molding of the optical reflection member is difficult. This may be difficult, or it may not be possible to mold an optical reflection member having excellent mirror surface properties.

If the average length of the inorganic fibers is less than 5 μm or the average diameter is less than 0.01 μm, the high rigidity required for the optical reflection member cannot be obtained. On the other hand, the average length of the inorganic fibers exceeds 0.3 mm, or the average diameter is 1 mm.
If it exceeds 5 μm, there arises a problem that the surface of the optical reflection surface does not become a mirror surface.

An inorganic fiber having an average length and an average diameter in the above-mentioned range is subjected to a surface treatment, preferably using a silane coupling agent or the like, and then compounded with a thermoplastic resin to be pelletized into a molding material. . By molding the optical reflecting member using such a molding material and a mold incorporating a nest, high rigidity, a high modulus of elasticity, a low coefficient of linear expansion, and a high load deflection temperature (heat resistance) can be obtained. It is possible to obtain an optical reflection member having excellent mirror-like properties (image clarity).

The inorganic fiber comprises glass fiber, glass flake, carbon fiber, wollastonite, aluminum borate whisker fiber, potassium titanate whisker fiber, basic magnesium sulfate whisker fiber, calcium silicate whisker fiber, and calcium sulfate whisker fiber. It is preferable to be composed of at least one material selected from the group. The number of inorganic fibers contained in the thermoplastic resin is not limited to one, and two or more kinds of inorganic fibers may be contained in the thermoplastic resin.

The average length of the inorganic fibers means the weight average length. The length of the inorganic fiber is measured by dissolving the resin component by immersing a molding pellet or an optical reflecting member containing the inorganic fiber in a liquid that dissolves the resin component of the thermoplastic resin, The resin component is burned at a high temperature of ゜ C or higher, and the remaining inorganic fibers can be observed and measured with a microscope or the like. Usually, a person measures the length by taking a photograph of the inorganic fiber, or obtains the length of the inorganic fiber using a dedicated fiber length measuring device. Since the number average length has too great an effect of the finely broken fibers, it is preferable to use the weight average length. When measuring the weight average length,
The measurement is performed excluding the fragments of the inorganic fibers that have been crushed too small. If the length is shorter than twice the nominal diameter of the inorganic fiber, the measurement becomes difficult. Therefore, for example, an inorganic fiber having a length twice or more the nominal diameter is measured.

In the mold used in the optical reflecting member or the method of manufacturing the same according to the present invention, the resin injection portion (so-called gate portion) for injecting the molten thermoplastic resin into the cavity has an optical reflecting surface. Can be provided as long as it is a part of the mold other than the mold surface for forming the pattern. In addition, depending on the structure of the mold, during the production of the optical reflecting member, the molten thermoplastic resin injected into the cavity may be changed from the part of the optical reflecting member constituting the entire area of the optical reflecting surface to the solid part. It is desirable to dispose the resin injection part in the mold so that the resin flows toward the mold.

In the mold used in the optical reflecting member or the method of manufacturing the same according to the present invention, the pressurized fluid introduction part also includes:
Any part of the mold other than the mold surface for forming the optical reflection surface can be provided without any particular positional restrictions.
Specifically, the pressurized fluid introduction unit may be arranged near the resin injection unit, may be arranged separately from the resin injection unit, or may be arranged inside the resin injection unit. In addition, the number of pressurized fluid introduction sections is not limited.

The pressurized fluid used is a gaseous substance at normal temperature and normal pressure, and is preferably one that does not react with or mix with the thermoplastic resin used. Specifically, nitrogen gas, air, carbon dioxide gas, helium and the like can be mentioned, but from the viewpoint of safety and economy, nitrogen gas and helium gas are preferable. The timing of starting the introduction of the pressurized fluid into the molten thermoplastic resin in the cavity is preferably 0.1 second to 25 seconds from the start of the injection of the molten thermoplastic resin into the cavity. The lower limit of the introduction start time of the pressurized fluid is that when the pressurized fluid is introduced into the molten thermoplastic resin in the cavity while the molten thermoplastic resin is being injected into the cavity, the introduced pressurized fluid is The time may be set so that the molten thermoplastic resin is not blown off. On the other hand, if the introduction start time of the pressurized fluid exceeds 25 seconds, a desired hollow portion cannot be formed due to solidification of the molten thermoplastic resin in the cavity, and sinks occur on the optical reflection surface, and the mirror surface of the optical reflection surface May impair the performance. The timing of starting the introduction of the pressurized fluid into the molten thermoplastic resin in the cavity may be during injection of the molten thermoplastic resin into the cavity, simultaneously with the completion of the injection, or after the completion of the injection.

The volume of the molten thermoplastic resin to be injected into the cavity may be any volume that can mold a desired optical reflecting member, and depends on the volume occupied by the hollow portion in the optical reflecting member. That is, the volume of the molten thermoplastic resin to be injected into the cavity may be a volume that completely fills the cavity or a volume that does not completely fill the cavity. If desired, an overflow portion into which excess molten thermoplastic resin flows from the cavity may be provided in the mold in communication with the cavity, and the entire optical reflection surface may be formed as a hollow portion.

The thermoplastic resin used in the optical reflecting member of the present invention or the method for producing the same may be any thermoplastic resin, such as polycarbonate resin; olefinic resin such as polyethylene resin and polypropylene resin; polystyrene resin; Styrene resins such as resin, ABS resin and AES resin; methacrylic resins such as PMMA resin;
Polyoxymethylene (polyacetal) resin; polyamide resin such as polyamide 6, polyamide 66, polyamide MXD; modified polyphenylene ether (PPE) resin; polyphenylene sulfide resin; polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin Polyester resins; thermoplastic resins such as liquid crystal polymers, and polymer alloys composed of at least two or more of these thermoplastic resins. Among them, polycarbonate resin,
It is preferable to use a thermoplastic resin selected from the group consisting of a polyamide resin, a polyphenylene ether resin, a polyester resin, and a polymer alloy resin composition of a polycarbonate resin / polyester resin. These thermoplastic resins may contain the above-mentioned inorganic fibers in order to impart mechanical properties represented by rigidity, dimensional stability, and mirror angle accuracy to the optical reflecting member.

As the polycarbonate resin, it is desirable to use an aromatic polycarbonate. In particular,
2,2 bis (4-hydroxyphenyl) -propane, 2,
A polymer obtained by a known method from one or more divalent phenolic compounds exemplified by 2-bis (3,5-dibromo-4-hydroxyphenyl) propane and a carbonate precursor exemplified by phosgene Can be exemplified. In particular, in the present invention, in addition to high rigidity, transparency,
From the requirements of heat resistance and impact resistance, the viscosity average molecular weight calculated from the melt viscosity of methylene chloride at 25 ° C is 1
5000 to 30000 aromatic polycarbonate resins are preferred.

The optical reflecting member of the present invention or the thermoplastic resin used in the method for producing the same may contain a dye in order to give an arbitrary color tone. For example, it can be selected from those usually used for coloring thermoplastic resins, such as azo dyes, cyanine dyes, quinoline dyes, and perylene dyes. The compounding amount may be appropriately selected, for example, within a range that does not impair transparency. Further, within a range that does not impair the object of the present invention, for example, an effective expression amount of a stabilizer, a release agent, and an ultraviolet absorber may be blended in the thermoplastic resin.

In the optical reflecting member of the present invention, an optical reflecting film may be provided on the surface of the optical reflecting surface. In the method for manufacturing an optical reflection member of the present invention, after the step (d), an optical reflection film may be formed on the surface of the optical reflection surface. The thickness of the optical reflection film may be a thickness capable of effectively reflecting light, and is at least 50 n.
m, preferably 50 nm to 500 nm, more preferably 100 nm to 300 nm.
If it is less than 50 nm, the reflectivity may not be sufficient. On the other hand, if it exceeds 500 nm, the surface smoothness of the optical reflection surface may be reduced, and a problem may occur in the mirror surface.

As a material constituting the optical reflection film, for example, gold, platinum, silver, chromium, nickel, phosphorus nickel,
Examples thereof include metals such as aluminum, copper, beryllium, beryllium copper, and zinc, and metal compounds and alloys thereof. As the film forming method, (a) various kinds of vacuum evaporation methods such as an electron beam heating method, a resistance heating method, and flash evaporation; (b) a plasma evaporation method; (c) a bipolar sputtering method, a DC sputtering method, a DC magnetron sputtering method, and a high-frequency sputtering method Methods, magnetron sputtering method, ion beam sputtering method, bias sputtering method, etc. (d) DC (direct current) method, RF method, multi-cathode method, activation reaction method, electric field evaporation method, high frequency ion plating method PVD (Physical Vapor Depositio), such as various ion plating methods such as reactive ion plating
n) Method can be mentioned. In terms of reflectivity and cost,
Most preferably, the optically reflective film is formed from an aluminum vapor-deposited film obtained by vacuum-depositing aluminum.

In the optical reflecting member of the present invention or the optical reflecting member obtained by the method of manufacturing the same, the optical reflecting surface may be flat, spherical, or spheroidal depending on the specifications of the optical reflecting member. , And may have any three-dimensional shape such as a paraboloid of revolution. Further, the number of optical reflection surfaces is not limited to one. When the optical reflecting surface is a flat surface, the optical reflecting surface preferably has a warpage ratio W of 1 × 10 ⁻³ or less (0.1% or less). The warpage ratio W of the optical reflecting surface is assumed to be a line segment (length L) connecting any two points on the edge of the optical reflecting surface, and the optical reflection from the line segment is performed along the line segment. measuring the distance to the surface (D), the maximum value of the distance when the D _MAX, can be expressed by the following equation. When the warpage ratio W (L) is 1 × 10 ⁻³ or less for an arbitrary line segment,
It is assumed that “the warp rate of the optical reflection surface is 1 × 10 ⁻³ or less”.

[Equation 1] W (L) = D _MAX / L

The optical reflecting member of the present invention thus obtained is required to have high specularity, dimensional accuracy, light weight, safety, durability, and economic efficiency. It is an optical reflecting member suitable for many uses, such as for building, building materials, and household goods. As an embodiment of the optical reflection member of the present invention, a mirror can be given. More specifically, vehicle mirrors such as room mirrors, door mirrors, fender mirrors, mirrors built into speedometers, roof mirrors for cameras, optical mirrors for copiers,
Examples include an optical system mirror such as a polygon mirror for a laser beam printer, and an optical reflecting member integrated with a holding unit which is a mechanism for holding these mirrors.
Further, as another form, a reflector can be cited. More specifically, a reflector incorporated in a headlamp, a turn lamp, a search light, a rotating light, an emergency light, and the like, and an optical reflecting member integrated with a holding unit that is a mechanism unit for holding these are exemplified. can do.

In the present invention, since the hollow portion is provided in the portion of the optical reflecting member which constitutes the entire area of the optical reflecting surface, that is, when molding the optical reflecting member, the entire area of the optical reflecting surface is formed. Since the hollow portion formed by the introduction of the pressurized fluid suppresses the contraction of the thermoplastic resin in the portion of the optical reflecting member to be formed, an optical element having extremely excellent specularity over the entire optical reflecting surface. A reflective member can be obtained.
In addition, if a mold having a low thermal conductivity is used for a mold surface for forming an optical reflection surface, for example, when a thermoplastic resin containing inorganic fibers capable of satisfying characteristics required for a holding portion is used. However, excellent mirror finish can be ensured.

[0052]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings based on preferred embodiments. The optical reflection member made of a thermoplastic resin to be manufactured in Examples 1 to 5 and Comparative Examples 1 to 3 was an optical reflection mirror for a laser beam printer. In Examples 6 to 7 and Comparative Examples 4 to 7, an optical reflecting member having a holding portion for holding an optical reflecting surface was provided, and the optical reflecting surface and the holding portion were integrated. (Specifically, an optical reflection mirror for a laser beam printer). The measurement of the plane accuracy of the optical reflecting surface was performed by evaluating interference fringes using a 10 mm diameter optical flat. The measurement site was the center of the optical reflection surface. The evaluation results are indicated by a mark “◎” when the number of observed interference fringes is 5 or less, a mark “干 渉” when the number of interference fringes is 6 or more and 10 or less, and a case where the number of interference fringes is 11 or more and 20 or less. “△” mark, “×” when there are 21 or more interference fringes
Indicated by a mark. In addition, the specularity evaluation of the optical reflection surface was performed using a surface image clarity measuring device (ICP-2DP manufactured by Suga Test Instruments). The specularity of the optical reflection surface was evaluated with a measurement range of 10 mm in diameter, an incident and light receiving angle of 60 degrees, and an optical comb width of 0.5 mm.

(Example 1) FIG. 1A is a schematic side view of the optical reflecting member 10 formed in Example 1 in the long side direction. FIG. 1B is a schematic cross-sectional view when the optical reflecting member 10 is cut along a vertical plane including the dividing line.
(A line CC in FIG. 1A)
FIG. 1C shows a schematic cross-sectional view taken along the line of FIG. The external dimensions of the optical reflecting member 10 are 310 mm in length and 16 in width.
mm, and the dimension of the optical reflection surface 13 is 240 m in length.
m, the width is 12 mm, and the optical reflection surface is flat.

The optical reflecting member 10 has an optical reflecting surface 13
(One surface), and a hollow portion 14 formed by introducing a pressurized fluid is provided in the hollow portion constituting portion 11 of the optical reflecting member 10. Further, a solid part 12 extends from the hollow part 11 to the left hand side of the hollow part 11. On the other hand, on the right-hand side of the hollow component 11, traces of the injection of the molten thermoplastic resin (traces of the resin injection portion) 15 and traces of the pressurized fluid introduced (traces of the pressurized fluid introduction portion) 16 Remains.

In Example 1, an injection molding machine provided with an injection molding die 20 whose schematic sectional view is shown in FIG. 2 was used. Except for the heating cylinder 26, the components of the injection molding machine are not shown. The mold 20 includes a fixed mold portion 21 having a cavity 24 and a nest 23 forming a mold surface for forming the optical reflection surface 13, and a movable mold portion 22. When the fixed mold part 21 and the movable mold part 22 are clamped, a cavity 24 is formed. The mold 20 is provided with a resin injection part 25 opened to the cavity 24, and the resin injection part 25 communicates with the heating cylinder 26. Further, a pressurized fluid introduction unit 27 is provided in the resin injection unit 25, and one end of the pressurized fluid introduction unit 27 is opened in the resin injection unit 25.
On the other hand, the other end of the pressurized fluid introducing section 27 is connected to a pressurized fluid source 28. A check valve (not shown) is provided between the other end of the pressurized fluid introduction unit 27 and the pressurized fluid source 28,
The structure is such that the pressurized fluid in the hollow portion does not flow backward toward the pressurized fluid source 28. The resin injection section 25 is disposed in a mold so as to inject a molten thermoplastic resin into a cavity for forming a portion of the optical reflection member other than the hollow component 11. That is, the optical reflection surface is not formed depending on the mold surface near the resin injection portion (gate portion) 25. In Example 1, the insert 23, the fixed mold part 21, and the movable mold part 22 were made of a stainless steel material (S55C). The surface roughness _Ry of the mold surface of the insert 23 was set to 0.01 μm. The measurement of the surface roughness R _y was in accordance with JIS B0601.

In Example 1, an SH-100 injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. was used as the injection molding machine, and the heating cylinder 26 was heated to 300 ° C.
20 ° C. As the thermoplastic resin, a polycarbonate resin having a viscosity average molecular weight of 21,000 (trade name: Iupilon S-3000, manufactured by Mitsubishi Engineering-Plastics Corporation), which is a thermoplastic resin for injection molding, was used. Nitrogen gas was used as the pressurized fluid.

In the first embodiment, the thermoplastic resin is supplied into the heating cylinder 26,
After being kneaded and plasticized in 6 and melted, the molten thermoplastic resin 30 was injected into the cavity 24 of the mold 20 via the resin injection section 25. FIG. 3 schematically shows a state in which the molten thermoplastic resin 30 is being injected. The injection time is 1 second, and the volume of the injected molten thermoplastic resin is 8 times the volume of the cavity 24.
5%. And the cavity 2 of the molten thermoplastic resin.
Simultaneously with the completion of the injection into 4, the pressurized fluid is introduced into the molten thermoplastic resin 30 in the cavity 24 from the pressurized fluid introduction portion 27, whereby the hollow portion 14 is formed in the hollow component portion 11 ( (See FIG. 4). The pressure of the pressurized fluid when introducing the pressurized fluid into the molten thermoplastic resin 30 in the cavity 24,
3.5 × 10 ⁶ Pa (3.5 × 10 kgf /
cm ² -G).

Thereafter, without performing the pressure-holding operation, until the thermoplastic resin in the cavity 24 is solidified and cooled (from the time when the injection of the molten thermoplastic resin into the cavity is completed, 4 hours).
0 seconds), the pressure in the hollow portion 14 is increased
The pressure is controlled by the volume of the pressurized fluid that pressurizes the inside of the hollow portion 14 through the pressure chamber 7 and the pressure is 1.9 × 10 ⁶ Pa (1.9 × 10 kgf).
/ Cm ² -G). After that, the pressurized fluid in the hollow portion 14 was discharged into the atmosphere via the pressurized fluid introduction portion 27, the mold was opened, and the optical reflection member 10 was taken out. In the optical reflecting member 10 thus obtained, the hollow portion 1
4 is 15% of the volume of the optical reflecting member 10,
The volume occupied by the solid portion 12 was 8% of the volume of the optical reflection member 10. The optical reflecting surface 13 of the optical reflecting member 10 formed in the cavity 24 and the optical reflecting surface 13
There was only a gap of 1 μm or less per 10 mm ^{2 of the} optical reflecting surface between the mold surface of the insert 23 and the mold 23.

The flatness of the optical reflecting surface of the optical reflecting member thus obtained is shown in Table 1 below, and connects the points "X ₁ " and "X ₂ " in FIG. 1A. The warpage rate measured based on the line segment L ₀ is shown in Table 1 below. In the following Examples and Comparative Examples, the measurement of the warpage rate was the same.

On the optical reflection surface 13 of the molded optical reflection member 10, an aluminum vapor-deposited film is formed by a vacuum vapor deposition method.
A mirror was formed by depositing a film having a thickness of 20 nm. As a result, the optical reflection member 10 had excellent image clarity (specularity) equivalent to that of a normal glass mirror, and the subject was clearly displayed.

(Example 2) Until the thermoplastic resin in the cavity 24 is solidified and cooled (for 40 seconds after the injection of the molten thermoplastic resin into the cavity is completed), the hollow portion 14 is formed.
The internal pressure is controlled by the volume of the pressurized fluid that pressurizes the inside of the hollow portion 14 via the pressurized fluid introduction unit 27, and is 6.2 × 1
0 ⁶ except held in ^{Pa (6.2 × 10kgf / cm 2} -G) , based on the same method as in Example 1, to produce an optical reflecting member made of thermoplastic resin. Table 1 below shows the planar accuracy and the warpage ratio of the optical reflection surface of the optical reflection member obtained as described above.

(Embodiment 3) The pressure in the hollow portion 14 is maintained in a desired pressure range until the thermoplastic resin in the cavity 24 is solidified and cooled. In Embodiment 3, the desired pressure is maintained. The range was controlled by the pressure of the pressurized fluid when the pressurized fluid was introduced into the molten thermoplastic resin in cavity 24.

More specifically, in the third embodiment, the thermoplastic resin is supplied into the heating cylinder 26, kneaded and plasticized in the heating cylinder 26 and melted, and then injected into the cavity 24 of the mold 20. The molten thermoplastic resin 30 was injected through the part 25. The injection time is 1 second, and the volume of the injected molten thermoplastic resin is 85% of the volume of the cavity 24.
And Then, simultaneously with the completion of the injection of the molten thermoplastic resin into the cavity 24, the pressurized fluid is introduced into the molten thermoplastic resin 30 in the cavity 24 from the pressurized fluid introduction part 27, and thus the hollow part 11 is A hollow portion 14 was formed. The pressure of the pressurized fluid at the time of introducing the pressurized fluid into the molten thermoplastic resin 30 in the cavity 24 is set to 1.
The pressure was 9 × 10 ⁶ Pa (1.9 × 10 kgf / cm ² -G).

Thereafter, the pressure in the hollow portion 14 is increased until the thermoplastic resin in the cavity 24 is solidified and cooled (for 40 seconds after the injection of the molten thermoplastic resin into the cavity is completed). It was controlled by the pressure of the pressurized fluid introduced into it. The pressure in the hollow portion 14 immediately before opening the mold is 1.9 × 10 ⁶ Pa (1.9 × 10 kg) as a gauge pressure.
f / cm ² -G). After that, the pressurized fluid in the hollow portion 14 was released into the atmosphere via the pressurized fluid introduction portion 27, the mold was opened, and the optical reflection member 10 was taken out. In the optical reflecting member 10 thus obtained, the hollow portion 1
The volume of No. 4 was 15% of the volume of the optical reflection member 10.

(Embodiment 4) The pressure in the hollow portion 14 is maintained in a desired pressure range until the thermoplastic resin in the cavity 24 is solidified and cooled. The movable core 29 is further provided in place of the nest 23, a mold surface for forming an optical reflection surface is provided on the movable core 29, and the desired pressure range is controlled by controlling the position of the movable core 29. Control.

Specifically, as shown in a schematic cross-sectional view of FIG. 5, a movable core 29 that can be moved by, for example, a hydraulic cylinder (not shown) may be provided in the fixed mold portion 21. . And in molding the optical reflection member,
At the time of mold clamping, the fixed mold part 21 and the movable mold part 22 are clamped so that the volume (V _C ) of the cavity 24 is smaller than the volume (V _M ) of the optical reflection member to be molded. In addition, the position of the movable core 29 in the cavity is controlled. Then, the molten thermoplastic resin is injected into the cavity (volume: V _C ) 24, and further, a pressurized fluid is introduced into the molten thermoplastic resin in the cavity 24, and the hollow part 14 is formed in the hollow part 11. Form. Thereafter, the movable core 29 is moved by the operation of a hydraulic cylinder (not shown) to gradually or continuously increase the volume of the cavity 24 up to the volume (V _M ) of the optical reflecting member to be molded.
Or increase it all at once. Thus, the cavity 24
Until the thermoplastic resin inside solidifies and cools, the hollow part 1
The pressure in 4 is maintained in the desired pressure range.

Example 5 In Example 5, the insert 23 was made of ZrO ₂ —Y ₂ O ₃ . The surface roughness _Ry of the mold surface of the insert 23 was set to 0.01 μm. Other configurations of the mold 20 for injection molding were the same as those in Example 1. In Example 5, as the thermoplastic resin, a polycarbonate resin having a viscosity average molecular weight of 21500 (trade name: Iupilon GS-2030MLR, manufactured by Mitsubishi Engineering-Plastics Corporation), which is a thermoplastic resin for injection molding.
It was used. This polycarbonate resin contains 30% by weight of glass fiber. Then, the optical reflecting member 10 was formed in the same manner as in Example 1. On the optical reflection surface 13 of the molded optical reflection member 10, an aluminum vapor-deposited film having a thickness of 120 nm was formed by a vacuum vapor-deposition method to produce a mirror. As a result, despite the use of a thermoplastic resin containing glass fibers, the nest 23 was made of ZrO ₂ −
Since the optical reflecting member 10 was made of Y ₂ O ₃ , the optical reflecting member 10 had excellent image clarity (specularity) equivalent to that of a normal glass mirror, and the subject was clearly projected.

Comparative Example 1 In Comparative Example 1, an optical reflecting member having no hollow portion was formed without introducing a pressurized fluid. Specifically, the same injection molding machine, mold, and thermoplastic resin as those in Example 1 were used, and the thermoplastic resin was supplied into the heating cylinder 26, and kneaded and plasticized in the heating cylinder 26 to be melted. Thereafter, the molten thermoplastic resin was injected into the cavity 24 of the mold 20 via the resin injection section 25. The injection time was set to 1 second, and the volume of the injected molten thermoplastic resin was set to 100% of the volume of the cavity 24. After the injection of molten thermoplastic resin is completed, heating cylinder 2
From the 6 side, the holding pressure is 1 × 10 ⁸ Pa (1 × 10 ³ kgf /
cm ² -G) and a dwell operation for 40 seconds.
Next, the thermoplastic resin in the cavity 24 is applied for 20 seconds.
Cooled and solidified. Thereafter, the mold was opened, and the optical reflection member was taken out. Table 1 below shows the planar accuracy and the warpage rate of the optical reflection surface of the optical reflection member thus obtained.
Shown in

Comparative Example 2 The same as Comparative Example 1 except that after the injection of the molten thermoplastic resin was completed, the thermoplastic resin in the cavity 24 was cooled and solidified without performing a pressure-holding operation from the heating cylinder 26 side. The optical reflection member was produced by the method described in the above. Table 1 below shows the planar accuracy and the warpage ratio of the optical reflection surface of the optical reflection member obtained as described above. Between the optical reflection surface 13 of the optical reflection member 10 formed in the cavity 24 and the mold surface of the nest 23 for forming the optical reflection surface 13, the maximum per 10 mm ^{2 of the} optical reflection surface There was a gap of 15 μm.

(Comparative Example 3) The volume of the molten thermoplastic resin injected into the cavity 24 was reduced to 9 times the volume of the cavity 24.
The hollow portion was formed only in a part of the portion of the optical reflecting member constituting the optical reflecting surface. That is, the hollow portion was formed up to the center of the optical reflection surface. Except for this point, an optical reflection member made of a thermoplastic resin was manufactured based on the same method as in Example 1. Table 1 below shows the planar accuracy and the warpage ratio of the optical reflection surface of the optical reflection member obtained as described above.

[Table 1]

As is clear from Table 1, the optical reflecting members obtained in Example 1 and Example 2 satisfied both the planar accuracy and the warpage ratio of the optical reflecting surface.
On the other hand, the optical reflecting members obtained in Comparative Examples 1 to 3 did not satisfy any of the planar accuracy and the warpage rate of the optical reflecting surface.

(Embodiment 6) FIG. 6 is a schematic perspective view of the optical reflecting member 110 formed in Example 6, and FIG. 7 is a schematic cross-sectional view taken along line AA of FIG. Shown in

The optical reflecting member 110 is provided on the optical reflecting surface 1.
13 (one surface) and the optical reflection member 110
Is provided with a hollow portion 114 (indicated by a dotted line in FIG. 6) formed by introducing a pressurized fluid. 6, a solid part 112 extends from the hollow part 111 to the left hand side of the hollow part 11. On the other hand, on the right-hand side of the hollow part 11, a trace 115 where the molten thermoplastic resin is injected (trace of the resin injection part) and a trace 116 where the pressurized fluid is introduced (trace of the pressurized fluid introduction part) 116. Remains.

The optical reflecting member 110 is provided with a solid holding portion 121 for holding the optical reflecting surface 113. The optical reflecting surface 113 and the holding part 121 are integrally formed. When the holding unit 121 is viewed from above,
The portion 121A of the holding portion 121 and the optical reflection surface 11 which have a U shape and correspond to upper and lower horizontal bars of the U shape
3 are integrated with the end face. Reference number 121B is
This is a longitudinal portion of the holding portion 121 corresponding to a vertical bar having a U-shape. The size of the optical reflecting surface 113 is 150 mm in length,
The width is 10 mm, and the optical reflecting surface 113 is flat.
The design value of the angle θ between the optical reflecting surface 113 and the holding portion 121 was set to 45 degrees.

The injection molding machine and the mold used in the sixth embodiment have substantially the same structure as that shown in FIG. 2 and described in the first embodiment, except that the shape of the cavity 24 is different. Also in Example 6, the insert 23, the fixed mold part 21, and the movable mold part 22 were made of a stainless steel material (S55C). The surface roughness _Ry of the mold surface of the insert 23 was set to 0.01 μm.

In Example 6, an SG-125 injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. was used as the injection molding machine, the heating cylinder 26 was heated to 300 ° C., and the mold temperature was set to 100 ° C.
゜ C. As the thermoplastic resin, a polycarbonate resin having a viscosity average molecular weight of 21500 (trade name: Iupilon S-3000R, manufactured by Mitsubishi Engineering-Plastics Corporation), which is a thermoplastic resin for injection molding, was used. Nitrogen gas was used as the pressurized fluid.

In the sixth embodiment, the thermoplastic resin is supplied into the heating cylinder 26,
After being kneaded and plasticized in 6 and melted, the molten thermoplastic resin 30 was injected into the cavity 24 of the mold 20 via the resin injection section 25. The injection time was 5 seconds, and the volume of the injected molten thermoplastic resin was 90% of the volume of the cavity 24. Then, simultaneously with the completion of the injection of the molten thermoplastic resin into the cavity 24, a pressurized fluid is introduced into the molten thermoplastic resin 30 in the cavity 24 from the pressurized fluid introduction unit 27,
Thus, the hollow part 114 was formed in the hollow part constituent part 111. 2. The pressure of the pressurized fluid at the time of introducing the pressurized fluid into the molten thermoplastic resin 30 in the cavity 24 is expressed as a gauge pressure.
The pressure was set to 5 × 10 ⁶ Pa (3.5 × 10 kgf / cm ² -G).

The thermoplastic resin in the cavity 24 is solidified,
Until cooling (for 60 seconds after the completion of the injection of the molten thermoplastic resin into the cavity), the pressure in the hollow portion 114 is increased by pressurizing the inside of the hollow portion 114 via the pressurized fluid introducing portion 27. 2.5 × 10 ⁶ P controlled by the volume of the fluid
a (2.5 × 10 kgf / cm ² -G). After that, the pressurized fluid in the hollow portion 114 is
After 10 seconds, the mold was opened and the optical reflecting member 110 was taken out. In the optical reflecting member 110 thus obtained, the volume of the hollow portion 114 was 10% of the volume of the optical reflecting member 110. The optical reflecting surface 10 between the optical reflecting surface 113 of the optical reflecting member 110 formed in the cavity 24 and the mold surface of the nest 23 for forming the optical reflecting surface 113 is provided.
There was only a gap of 1 μm or less per mm ² . Table 2 below shows the results of the specularity evaluation of the optical reflection surface of the optical reflection member, the measured value of the angle θ formed between the optical reflection surface 113 and the holding portion 121, and the amount of warpage.
Note that the amount of warpage means the amount of warpage of the optical reflection surface 113 in a direction parallel to the longitudinal portion 121B of the holding unit 121.

On the optical reflection surface 113 of the molded optical reflection member 110, a 120 nm-thick aluminum vapor-deposited film was formed by a vacuum vapor deposition method to produce a mirror. as a result,
The optical reflection member 110 has excellent image clarity (mirror surface property) equivalent to that of a normal glass mirror, and the subject was clearly displayed.

Example 7 In Example 7, the insert 23 was made of ZrO ₂ —Y ₂ O ₃ . The surface roughness _Ry of the mold surface of the insert 23 was set to 0.01 μm. Other configurations of the injection mold were the same as those in the first embodiment. In Example 7, as the thermoplastic resin, the same polycarbonate resin as that of Example 5 (manufactured by Mitsubishi Engineering-Plastics Corporation, trade name Iupilon GS-2030M)
LR) was used. The molding conditions and method of the optical reflection member were the same as in Example 6. Table 2 below shows the results of the specularity evaluation of the optical reflecting surface of the obtained optical reflecting member, the measured values of the angle θ between the optical reflecting surface and the holding portion, and the amount of warpage.

Comparative Example 4 In Comparative Example 4, an optical reflecting member having no hollow portion was formed without introducing a pressurized fluid. Specifically, the same injection molding machine, mold, and thermoplastic resin as those of Example 6 were used, and the thermoplastic resin was supplied into the heating cylinder 26, kneaded and plasticized in the heating cylinder 26 and melted. Thereafter, the molten thermoplastic resin was injected into the cavity 24 of the mold 20 via the resin injection section 25. The injection time is 7.5 seconds, and the volume of the injected molten thermoplastic resin is 100% of the volume of the cavity 24.
And After the injection of the molten thermoplastic resin is completed, the holding pressure is set to 1 × 10 ⁸ Pa (1 × 10 ³ kg) from the heating cylinder 26 side.
f / cm ² -G) for 15 seconds and then the holding pressure is 5 × 10 ⁷ Pa (5 × 10 ² kgf / cm ² -G)
Then, the pressure-holding operation was performed for 45 seconds, and then the thermoplastic resin in the cavity 24 was cooled and solidified for 10 seconds. Thereafter, the mold was opened, and the optical reflection member was taken out. Table 2 below shows the results of the specularity evaluation of the optical reflecting surface of the optical reflecting member obtained as described above, the measured value of the angle θ between the optical reflecting surface and the holding portion, and the amount of warpage.

Comparative Example 5 In Comparative Example 5, using the thermoplastic resin used in Example 7, an optical reflecting member was molded under the same molding conditions and method as in Comparative Example 4. Table 2 below shows the results of the specularity evaluation of the optical reflecting surface of the obtained optical reflecting member, the measured values of the angle θ between the optical reflecting surface and the holding portion, and the amount of warpage.

Comparative Example 6 In Comparative Example 6, the thermoplastic resin used in Example 7 was used as the thermoplastic resin, and an optical reflecting member was molded under the same molding conditions and method as in Example 7. However, the nest 23 used was the nest 23 used in Example 6 (stainless steel-based material, manufactured in S55C). Table 2 below shows the results of the specularity evaluation of the optical reflecting surface of the obtained optical reflecting member, the measured values of the angle θ between the optical reflecting surface and the holding portion, and the amount of warpage.

Comparative Example 7 In Comparative Example 7, an optical reflecting member was molded under the same molding conditions and method as in Example 7. However, the volume of the molten thermoplastic resin injected into the cavity 24 was set to 95% of the volume of the cavity 24 (the injection time was 7.2 seconds). Then, simultaneously with the completion of the injection of the molten thermoplastic resin into the cavity 24, the pressurized fluid is introduced into the molten thermoplastic resin 30 in the cavity 24 by the pressurized fluid introduction unit 2.
7 to form a hollow part in the hollow part. However, the hollow part was formed only up to about half of the hollow part constituting part. Table 2 below shows the results of the specularity evaluation of the optical reflecting surface of the obtained optical reflecting member, the measured values of the angle θ between the optical reflecting surface and the holding portion, and the amount of warpage.

[Table 2]

As is clear from Table 2, the optical reflecting members obtained in Examples 6 and 7 have the specularity, the actual measured value of the angle θ between the optical reflecting surface and the holding portion, and the design. Both the difference in the values and the amount of warpage were satisfactory. On the other hand, the specularity of the optical reflecting members obtained in Comparative Examples 4 to 7 was insufficient. In particular, in Comparative Example 6,
Since the polycarbonate resin containing glass fiber was used as the thermoplastic resin, the difference between the measured value and the design value of the angle θ between the optical reflection surface and the holding portion and the amount of warpage were small, but the nest made from S55C was used. Therefore, the inorganic fibers precipitated on the surface of the optical reflection surface of the optical reflection member, and the specularity was extremely low at 15%. Comparative Example 5
In Comparative Example 6, since the pressurized fluid was not introduced into the molten thermoplastic resin injected into the cavity, the difference between the measured value and the designed value of the angle θ between the optical reflecting surface and the holding portion and the amount of warpage Has grown. In Comparative Example 7, since the hollow portion was formed only up to about half of the hollow portion constituting portion, the difference between the measured value and the designed value of the specularity, the angle θ formed between the optical reflection surface and the holding portion, and the warpage. The quantity was not satisfactory.

Although the present invention has been described based on the preferred embodiments, the present invention is not limited to these embodiments. The injection molding machine, the mold, and the used thermoplastic resin described in the embodiments are merely examples, and can be appropriately changed. The structure, shape, and dimensions of the optical reflecting member are also examples, and the design can be changed as appropriate.

FIG. 8A is a schematic sectional view of a polygon mirror 10A which is an example of the optical reflecting member of the present invention. The polygon mirror 10A shown in FIG.
FIG. 8B is a schematic cross-sectional view taken along line BB of FIG. Further, FIG. 9 is a schematic sectional view similar to FIG. 8B of polygon mirrors 10B and 10C, which are polygon mirrors which are an example of the optical reflecting member of the present invention and have slightly different structures from FIG. (A) and (B). FIG. 9A
In the polygon mirror 10B shown in FIG. 8, the structure of the solid portion 12 is different from the polygon mirror shown in FIG.
A hollow portion 14 extends further downward. The polygon mirror 10C shown in FIG. 9B differs from the polygon mirror shown in FIG. 8 in that the structure of the solid portion 12 extends outward, and the hollow portion 14 extends outward. It extends into the real part 12.

FIGS. 10 and 11 are schematic sectional views of reflectors 10D and 10E, which are examples of the optical reflecting member of the present invention. The structure of the hollow portion 14 and the solid portion 12 is slightly different between the reflector 10D shown in FIG. 10 and the reflector 10E shown in FIG.

[0091]

According to the present invention, a high-precision thermoplastic resin optical reflecting member having an optical reflecting surface (mirror surface) such as a mirror or a reflector can be prepared without requiring a separate process or a post-process. It can be manufactured stably, with high quality, efficiently and economically. In addition, an optical reflection member in which an optical reflection surface having high precision and a holding unit are integrated,
It can be manufactured stably, with high quality, efficiently and economically. Furthermore, by using a glass or ceramic nest, even if a reinforced thermoplastic resin containing inorganic fibers or the like is used, it is possible to obtain an optical reflecting member having an excellent optical reflecting surface. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an optical reflecting member formed in Examples 1 to 5 and Comparative Examples 1 to 3.

FIG. 2 is a schematic cross-sectional view of an injection molding machine and a mold used in Examples and Comparative Examples.

FIG. 3 is a schematic cross-sectional view of a mold and the like for explaining a method of manufacturing an optical reflection member of the present invention.

FIG. 4 is a schematic cross-sectional view of a mold and the like for explaining the method for manufacturing the optical reflection member of the present invention, following FIG. 3;

FIG. 5 is a schematic sectional view of a mold used in Example 4.

FIG. 6 is a schematic perspective view of an optical reflecting member formed in Examples 6 to 7 and Comparative Examples 4 to 7.

FIG. 7 is a schematic cross-sectional view of an optical reflecting member formed in Examples 6 to 7 and Comparative Examples 4 to 7.

FIG. 8 is a schematic sectional view of a polygon mirror which is an example of the optical reflection member of the present invention.

FIG. 9 is a schematic cross-sectional view of a polygon mirror which is an example of the optical reflection member of the present invention and has a structure slightly different from that of FIG.

FIG. 10 is a schematic cross-sectional view of a reflector that is an example of the optical reflecting member of the present invention.

11 is a schematic cross-sectional view of a reflector that is an example of the optical reflecting member of the present invention and has a structure slightly different from that of FIG. 10;

[Explanation of symbols]

10, 110 ... optical reflection member, 10A, 10B,
10C: polygon mirror, 10D, 10E: reflector, 11, 111: portion of optical reflection member, 12, 112: solid portion, 13, 113: optical reflection surface, 14 , 114 ... hollow part, 20 ... mold for injection molding, 21 ... fixed mold part, 22 ... movable mold part, 23 ... nest, 24 ... cavity,
25: resin injection section, 26: heating cylinder, 2
7 ... pressurized fluid introduction part, 28 ... pressurized fluid source, 29
... movable core, 30 ... molten thermoplastic resin, 121
... Holders

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) B29K 71:00 B29K 71:00 77:00 77:00 B29L 11:00 B29L 11:00 22:00 22: 00 (72) Inventor Yoshihiro Chino 5-6-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Inside the Technology Center of Mitsubishi Engineering Plastics Co., Ltd. (72) Inventor Kazuaki Ochiai 5-6-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture R-Engineering Plastics Corporation Technical Center F-term (reference) 2H042 DA01 DA02 DA03 DA04 DA05 DA07 DA11 DC02 DC08 DE00 DE01 DE04 DE08 4F202 AA24 AA28 AA29 AA32 AB16 AB25 AG07 AH78 AJ06 AR02 AR07 AR14 CA11 CB01 CD22 CK41 CL01A24A AA29 AA32 AB16 AB25 AG07 AH78 AJ06 AR025 AR075 AR14 JA05 JL02 JM05 JN27 JQ81

Claims (26)

[Claims] An optical reflecting member made of a thermoplastic resin having at least one optical reflecting surface, wherein a pressurized fluid is applied to a portion of the optical reflecting member that constitutes the entire area of the optical reflecting surface. An optical reflecting member, wherein a hollow portion formed by being introduced is provided. 2. A method according to claim 1, further comprising a solid portion extending from a portion of the optical reflecting member which forms the entire area of the optical reflecting surface, wherein the surface of the solid portion does not form the optical reflecting surface. Claim 1
4. The optical reflection member according to item 1. 3. The optical reflecting member according to claim 2, wherein the volume occupied by the solid portion is 5 to 60% of the volume of the optical reflecting member. 4. An optical reflection member is manufactured using an injection molding die provided with a cavity having a mold surface for forming an optical reflection surface. 3. The optical reflection device according to claim 2, wherein the molten thermoplastic resin injected into the cavity flows from a portion of the optical reflection member constituting the entire area of the optical reflection surface toward the solid portion. Element. 5. An optical reflection member is manufactured using an injection molding die provided with a cavity having a mold surface for forming an optical reflection surface, and the optical reflection member is formed in the cavity. ^{2. The method according} to claim 1, wherein there is only a gap of 1 μm or less per 10 mm ² of the optical reflection surface between the optical reflection surface of the reflection member and a mold surface for forming the optical reflection surface. The optical reflecting member according to any one of the preceding claims. 6. The optical reflecting member according to claim 1, wherein the optical reflecting surface is a flat surface. 7. The optical reflecting member according to claim 1, wherein a warp rate of the optical reflecting surface is 1 × 10 ⁻³ or less. 8. The optical reflection member according to claim 1, wherein an optical reflection film is provided on a surface of the optical reflection surface. 9. The optical reflecting member according to claim 1, further comprising a holding portion for holding the optical reflecting surface, wherein the optical reflecting surface and the holding portion are integrated. 10. An optical reflection member is manufactured using an injection molding die provided with a cavity having a die surface for forming an optical reflection surface, wherein the die surface has a thickness. The optical reflection member according to claim 1, wherein the optical reflection member is configured by a glass or ceramic nest having a size of 0.5 mm or more and 10 mm or less. 11. The thermal conductivity of the nest is 8.5 J / (m · s
· K) The optical reflecting member according to claim 10, wherein: 12. The nest is made of ZrO ₂ —Y ₂ O ₃ or 3Al ₂
O ₃ ceramic consisting -2SiO _2, or claim, characterized in that it is made of crystallized glass 11
4. The optical reflection member according to item 1. 13. The optical reflection member according to claim 10, wherein the thermoplastic resin contains an inorganic fiber. 14. A thermoplastic resin selected from the group consisting of a polycarbonate resin, a polyester resin, a modified polyphenylene ether resin, a polyamide resin, and a polymer alloy resin composition of a polycarbonate resin / polyester resin. Made of a plastic resin, the inorganic fibers are glass fiber, glass flake, carbon fiber, wollastonite, aluminum borate whisker fiber, potassium titanate whisker fiber, basic magnesium sulfate whisker fiber, calcium silicate whisker fiber, and calcium sulfate whisker. 14. The optical reflecting member according to claim 13, wherein the member is made of at least one material selected from the group consisting of fibers. 15. A hollow portion formed by introducing a pressurized fluid is provided in a portion of an optical reflecting member having at least one optical reflecting surface and constituting the entire area of the optical reflecting surface. A method for manufacturing an optical reflecting member made of a thermoplastic resin, comprising: using an injection molding mold provided with a cavity having a mold surface for forming the optical reflecting surface; Injecting a molten thermoplastic resin into the cavity; and (b) introducing a pressurized fluid into the molten thermoplastic resin in the cavity to form a hollow in a portion of the optical reflecting member constituting the entire optical reflecting surface. (C) maintaining the pressure in the hollow portion within a desired pressure range until the thermoplastic resin in the cavity is solidified and cooled; and (d) compressing the pressurized fluid in the hollow portion. After removing, open the mold,
Taking out the optical reflection member. A method for manufacturing an optical reflection member, comprising: 16. The desired pressure range in the step (c) is as follows:
The method according to claim 15, wherein the gauge pressure is 1 × 10 ⁵ Pa or more and 1 × 10 ⁷ Pa or less. 17. The desired pressure range in the step (c) is set as follows:
17. The method according to claim 16, wherein the control is performed by the pressure of a pressurized fluid that pressurizes the hollow portion until the thermoplastic resin in the cavity is solidified and cooled. 18. The desired pressure range in the step (c) is set as follows:
The method according to claim 16, wherein the control is performed by a volume of the pressurized fluid introduced in the step (b). 19. The manufacturing method according to claim 16, wherein the mold further comprises a movable core, and a desired pressure range in the step (c) is controlled by controlling the position of the movable core. Method. 20. The method according to claim 15, wherein after the step (d), an optical reflection film is formed on the surface of the optical reflection surface. 21. The optical reflection device according to claim 15, wherein the optical reflection member has a holding portion for holding the optical reflection surface, and the optical reflection surface and the holding portion are formed integrally. Manufacturing method of the member. 22. The method according to claim 15, wherein the mold surface for forming the optical reflection surface is made of a glass or ceramic nest having a thickness of 0.5 mm or more and 10 mm or less. Item 22. The method for producing an optical reflection member according to Item 21. 23. The thermal conductivity of the nest is 8.5 J / (m · s).
・ K) The method according to claim 22, wherein: 24. The nest is made of ZrO ₂ —Y ₂ O ₃ or 3Al ₂
O ₃ ceramic consisting -2SiO _2, or claim, characterized in that it is made of crystallized glass 23
3. The method for producing an optical reflection member according to item 1. 25. The optical reflection member according to claim 22, wherein the thermoplastic resin contains inorganic fibers. 26. A thermoplastic resin selected from the group consisting of a polycarbonate resin, a polyester resin, a modified polyphenylene ether resin, a polyamide resin, and a polymer alloy resin composition of a polycarbonate resin / polyester resin. Made of a plastic resin, the inorganic fibers are glass fiber, glass flake, carbon fiber, wollastonite, aluminum borate whisker fiber, potassium titanate whisker fiber, basic magnesium sulfate whisker fiber, calcium silicate whisker fiber, and calcium sulfate whisker. 26. The optical reflecting member according to claim 25, wherein the optical reflecting member is made of at least one material selected from the group consisting of fibers.