Multi-color molding article, multicolor molding method and substrate storage container

A multicolor molding article is integrally formed of first and second molding materials in combination. At least part of the peripheral portion in the boundary between a first molding part of the first molding material and a second molding part of the second molding material is formed with a thin projected piece. The tapering inclined angle of the thin projected piece is specified to range from 5° to 40°.

TECHNICAL FIELD

The present invention relates to a multicolor molding article, a multicolor molding method and a substrate storage container, which use different materials or the same materials in combination to form an one-body structure.

BACKGROUND ART

Conventionally, in mechanical parts of various machinery apparatuses, substrate storage containers and the like, in order to meet the different demanded properties of plural parts that constitute a product, a technique for obtaining a product of different materials by separately forming plural parts from different materials and assembling these plural parts into one-body structure has been adopted. As a manufacturing method of such products, insert molding and multicolor molding (also called two color molding or double molding) can be mentioned. In the multicolor molding process, two materials are selected and used from the viewpoint of whether the two molding materials can be joined or not (see patent documents 1 and 2)Patent document 1:

Japanese Patent Application Laid-open 2000-12673

DISCLOSURE OF INVENTION

Problems to be Solved by the Invention

Since, in the conventional multicolor molding method, two materials are used in combination, only from the viewpoint of whether two different molding materials can be joined or not, there is the problem that two kinds of molding materials cannot be suitably used in combination by placing weight on performance. For example, even though a combination of two kinds of molding materials is preferable from a performance viewpoint, if they are not compatible in view of whether they can be joined or not hence they are not a suitable combination, it is impossible to join them successfully. As a result, the combination cannot but be reconsidered.

If two kinds of molding materials are used in combination by placing weight on performance while neglecting the fact of unfavorable combination, the interface between two kinds of molding materials becomes weakened in strength, hence they would peel off due to stress during washing or due to vibration during usage or during transportation.

The present invention has been devised in view of the above, it is therefore an object to provide a multicolor molding article, a multicolor molding method and a substrate storage container, which can use a plurality of molding in suitable combination from a performance viewpoint.

Means for Solving the Problems

In order to solve the above problems, an article of the present invention is integrally formed of first and second molding materials in combination, and is characterized in that at least part of the peripheral portion in the boundary between a first molding part of the first molding material and a second molding part of the second molding material is formed with a thin projected piece, the tapering inclined angle of the thin projected piece being specified to range from 5° to 40°.

Here, the first molding material may be one of polycarbonate, cycloolefin polymer and polyether imide, and the second molding material may be one of polybutylene terephthalate, polypropylene, polyethylene, polyethylene terephthalate, polyacetal and polyether etherketone.

Further, the thin projected piece may be formed to have an approximately triangular section with its inclined surface specified to be 0.4 to 5.0 mm in length.

Also, in order to solve the above problems, a molding method of the present invention is to integrally mold the first and second molding materials in combination, and comprises the steps of: molding a first molding part using the first molding material; and, integrally molding the second molding part with the first molding part, using the second molding material while forming a thin projected piece having an approximately triangular section in at least part of the peripheral portion of the boundary between the first and second molding parts, the tapering inclined angle of the thin projected piece being specified to range from 5° to 40° and its inclined surface specified to be 0.4 to 5.0 mm in length.

Here, the first molding material may be one of polycarbonate, cycloolefin polymer and polyether imide, and the second molding material may be one of polybutylene terephthalate, polypropylene, polyethylene, polyethylene terephthalate, polyacetal and polyether etherketone.

Further, in order to solve the above problems, a container of the present invention includes supporting structures that are disposed on both sides inside a container body for storing substrates and support substrates in array, each supporting structure being formed of the multicolor molding article defined in Claim1,2or3, and is characterized in that the supporting structure includes a supporting piece formed of the first molding material and positioned on the inner side in the container body and a contact layer formed of the second molding material and integrally laminated (laid over to form a layer) over, at least, the supporting piece to come in contact with the substrate, and, at least part of the peripheral portion of the boundary between the supporting piece and the contact layer is formed with a tapering thin projected piece, the tapering inclined angle of the thin projected piece being specified to range from 5° to 40°.

Here, it is preferred that the supporting structure is formed of the first molding material, arranged on the inner side in the container body, and includes a supporting wall for supporting the supporting pieces.

It is also preferred that an interposed layer made of a material different from the second molding material is formed between the inner side in the container body and the supporting wall of the supporting structure.

It is still preferred that the supporting structure includes the contact layer of the second molding material that is layered over the supporting wall and comes in contact with the substrate at the portion closest to the supporting wall.

Further a project that is in contact with the substrate may be formed on the top surface of the contact layer laminated on the supporting piece of the supporting structure.

Also, the supporting piece of the supporting structure may include a first supporting part that is projected inwards from the inner side in the container body and opposes the side portion of the substrate at a position close to the front end and a second supporting part that is projected inwards from the inner side in the container body and opposes the side portion of the substrate at a position close to the rear end, and the contact layer may be formed over at least the top surface of the exposed areas of the first and second supporting parts.

It is also possible to provide a configuration, wherein the supporting piece of the supporting structure includes a first supporting part that is projected inwards from the supporting wall and opposes the side portion of the substrate at a position close to the front end and a second supporting part that is projected inwards from the supporting wall and opposes the side portion of the substrate at a position close to the rear end, and the contact layer is formed over the exposed areas of the first and second supporting parts while a contact layer is laminated between the supporting wall and the second supporting part, and, at least part of the peripheral portion of the boundary between the supporting wall and the contact layer is formed with a tapering thin projected piece, the tapering inclined angle of the thin projected piece being specified to range from 5° to 40°.

Also, a shelf may be interposed between the first and second supporting parts of the supporting structure.

Further, the top surface of the contact layer laminated on the exposed areas of the first and second supporting parts may be inclined so as to render a circular cone having a center that is approximately concentric with the substrate.

Still more, at least part of the peripheral portion of the boundary between the supporting wall and the contact layer may be formed with a tapering thin projected piece, the tapering inclined angle of the thin projected piece being specified to range from 5° to 40°.

Moreover, in order to solve the above problems, a container of the present invention includes supporting structures that are disposed on both inner sides in a container body for storing substrates and support substrates in array, each supporting structure being formed of the multicolor molding article defined in Claim1,2or3, and is characterized in that the supporting structure includes a supporting wall formed of the first molding material and positioned on the inner side in the container body and a supporting piece molded of the second molding material on the supporting wall to come in contact with and support the substrate, and at least part of the peripheral portion of the boundary between the supporting wall and the supporting piece is formed with a tapering thin projected piece, the tapering inclined angle of the thin projected piece being specified to range from 5° to 40°.

Here, the supporting piece of the supporting structure may preferably include a first supporting part that is projected inwards from the supporting wall and opposes the side portion of the substrate at a position close to the front end and a second supporting part that is projected inwards from the supporting wall and opposes the side portion of the substrate at a position close to the rear end.

Herein, the first and second molding materials in the claims may be either the same materials or different materials. The multicolor molding articles may, at least, include various kind of buttons, key top, knobs for various machines, tweezers, automobile-related products (driver's seat illumination parts etc.), lens hoods for cameras, grips for digital cameras, control part for mobile phones, part of substrate storage containers for storing various kinds of substrates such as glass substrates, semiconductor wafers etc., wafer trays, substrate handling jigs. When the multicolor molding article is part of a substrate storage container, it does not matter whether it is part of a top open box type, front open box type or bottom open box type.

It does not matter whether the first and second molding parts are singular or plural. The thin projected piece may be either part of the peripheral portion of the boundary between the first and second molding parts, or part of the peripheral portion and its interior side. Also, it may be the whole part of the peripheral portion in the boundary between the first and second molding parts. This thin projected piece is preferably formed in an approximately triangular shape, specifically, in the form of a right triangle or a shape that is regarded as an approximately right triangle. Further, the first and second supporting parts are preferably positioned apart from each other.

According to the present invention, when a multicolor molding article is formed, it is possible to obtain a multicolor molding article of different materials or of the same materials by molding the first molding part to be the primary side of the first molding material, setting it in the mold for forming the second molding part, charging the second molding material into this mold to form the second molding part to be the secondary side, and forming, at least, part of the peripheral portion in the boundary between the first and second molding parts into thin projected piece and fusing (melting with heat) it to join.

Effect of the Invention

The present invention has the effect that a plurality of molding materials, in particular, plural kinds of different molding materials can be suitably used in combination in view of performance. Further, since the tapering inclined angle of the thin projected piece is specified to be within the range of 5° to 40°, the molding material can be filled into the front end of the thin projected piece, it is hence possible to join the first and second molding parts firmly.

Further, when thin projected piece is formed to have an approximately triangular section with its inclined surface specified to be 0.4 to 5.0 mm long, excellent joining can be expected. In addition it is possible to charge the molding material sufficiently and stabilize molding.

Further, when the supporting structure includes a contact layer that is formed with the supporting wall and comes into contact with the substrate at its closest portion to the supporting wall, the contact layer comes into contact with the substrate at its close portions to the supporting walls when the substrate is taken in and out, and it is hence possible to prevent abrasion and damage accompanied by contact between the substrate and the supporting walls.

Further, when the top surface of the contact layer laminated on the exposed areas of the first and second supporting parts is inclined so as to render a circular cone having a center that is approximately concentric with the substrate, the substrate is automatically centralized due to gravity when the substrate storage container is of a front open box type and the substrates are stored and supported horizontally. Accordingly, it is possible to position the substrate correctly. Further, since a force that centralizes the substrate toward the center acts on and constrains the substrate at any time, this configuration has the effect that rotation of the substrate can be limited.

DESCRIPTION OF REFERENCE NUMERALS

Now, preferred embodied modes of the present invention will be described with reference to the drawings. In a multicolor molding article and multicolor molding method in the present embodiment, as shown inFIGS. 1 to 3, when preparing first and second molding materials different in material properties from each other and combining and integrating a pair of first molding parts1of the first molding material with a second molding part3of the second molding material, the peripheral portion in a linear boundary6between each first molding part1and second molding part3is formed with an acute-angled thin projected piece5having an approximately triangular section.

Though not particularly limited, various kinds of thermoplastic resins are used for the first molding material; specifically, polycarbonate, cycloolefin polymer or polyether imide or the like may be selected. Also, the second molding material is not particularly limited, but for example, various kinds of thermoplastic resins, which are more excellent in sliding performance, heat-resistance and wear resistance than the first molding material and difficult to be fused (melted with heat) with the first molding material, are used; specifically, polybutylene terephthalate, polypropylene, polyethylene, polyethylene terephthalate, polyacetal, polyether etherketone or the like may be selected.

As shown inFIGS. 2 and 3, the paired first molding parts1are formed into approximately block shapes having equally sized sections and function to hold second molding part3therebetween. In the interface of each first molding part1in contact with second molding part3, a projected portion2to be fitted to second molding part3is projectively formed. Further, as shown inFIGS. 2 and 3, second molding part3is formed into a block shape having a section longer than first molding part1and its interface in contact with each first molding part1is hollowed with a depressed portion4that mates with projected portion2of first molding part1.

As shown in the same drawings, thin projected piece5is formed in a shape having an approximately right triangular section (also a wedge-like section) that becomes thinner toward the distal end, and the tapering inclined angle θ formed between an inclined surface7that forms boundary6and the horizontal surface is specified to range from 5° to 40°, preferably 10° to 30°, and more preferably 15° to 20° while the length L of inclined surface7is specified to range from 0.4 to 5.0 mm.

The reason why the tapering inclined angle θ of thin projected piece5is specified within the range of 5° to 40° is that if the inclined angle θ is less than 5°, the front end part of thin projected piece5cannot be sufficiently filled with the first and second molding materials from experimental results. In contrast, if inclined angle θ exceeds 40°, it is impossible to form robust joining between each first molding part1and second molding part3from experimental results. The inclined angle θ of tapering thin projected piece5ranging from 10° to 30° is the most suitable in view of multicolor molding stability and joint reliability.

The reason why the length L of inclined surface7of thin projected piece5is specified within the range of 0.4 to 5.0 mm is that if the length L is less than 0.4 mm, sufficient joining cannot be expected from experimental results. In contrast when the length L exceeds 5.0 mm, it is impossible to fill the first and second molding materials properly from experimental results, making molding unstable.

In the above, when multicolor molding articles such as mechanical parts of various machinery equipment, buttons, key top, knobs, tweezers and the like are molded, first, the first molding material made of plasticized polycarbonate or the like is charged into an unillustrated mold so as to from a pair of first molding parts1to be the base. Then, each first molding part1is separated from the mold and inserted into a mold (not shown) for forming second molding part3, so as to section part of the cavity wall surface of the mold by each first molding part1.

After a pair of first molding parts1have been inserted in the mold for the second molding part, the second molding material made of plasticized polybutylene terephthalate or the like is charged into the mold so as to form second molding part3while forming acute-angled thin projected piece5in the peripheral portion of boundary6between each first molding part1and second molding part3for joining in fusion. Thereafter, the product is cooled and dismounted from the mold so as to complete a multicolor molding article.

According to the above configuration, even when the combination of the first and second molding materials are unfavorable in view of joining, the peripheral portions of boundaries6between first and second molding parts1and3are integrated by forming thin projected pieces5so that it is possible to combine properly and firmly without using high pressure and/or heat. As a result, there is no need of reconsidering the combination from the viewpoint of joining. Accordingly, it is possible to select a suitable combination of two kinds of molding materials, placing weight on performance, even though the two are poor in compatibility. Further, it is possible to reliably prevent the interface between two kinds of molding materials from weakening in strength and the materials from peeling off due to stress during washing or due to vibration during usage and during transportation.

Next, a substrate storage container using the above multicolor molding articles or multicolor molding method will be described. A substrate storage container of the present embodiment includes: as shown inFIGS. 4 to 11, a container body10for accommodating a plurality of substrates W, or round semiconductor wafers of 300 mm in diameter; and a door20to open and close the open front of the container body10with a sealing gasket24interposed therebetween. A pair of supporting structures30for supporting plural substrates W in array are disposed on the opposing side walls of container body10, each supporting structure30being formed of a multicolor molding article.

The molding material for container body10and door20is not particularly limited, but is preferably selected from thermoplastic resins such as, for example polycarbonate, polyether imide, cycloolefin resins etc.

As shown inFIGS. 4 and 5, container body10is formed of, for example transparent polycarbonate or the like, in a front open box type having an opening on the front side. Formed on the underside at both sides on the front side and at the center in the rear are positioning jigs having an approximately inverted V-shaped section, which are to be fitted from above into positioning pins of unillustrated semiconductor processing equipment. Attached to the top center is a removable robotic handle11to be held by an unillustrated automaton.

The front side of container body10is formed with a rim portion12for fitting door20, which is swelled sidewards and outwards. A plurality of engagement holes13for locking mechanisms26of door20are hollowed and positioned apart at top and bottom on the inner peripheral surface of the rim portion12. Further, on the interior rear wall of container body10, plural pairs of left and right rear retainers14for horizontally fitting and holding substrates W at their rear periphery are arranged from top to bottom with a predetermined pitch. Also, hand carriage handles (not shown) are removably attached to the both exterior side walls of container body10.

As shown inFIGS. 4 and 5, door20is comprised of a casing21having a laterally long approximately rectangular shape in front view, removably fitted to rim portion12of the container body front and a plurality of cover plates22having approximately rectangular shapes for removably covering the open front in both sides of the casing12. Incorporated between these casing21and plural cover plates22are a pair of left and right locking mechanisms26that are engaged with engagement holes13of container body10to lock.

Casing21is formed so as to have an approximately dish-like section and has a frame-like stepped hollow23cut out around the periphery on the rear side thereof that opposes substrates W. Elastic endless sealing gasket24is fitted in this stepped hollow23. This sealing gasket24is pressed and deformed inside rim portion12of container body10to assure air tightness. Attached in the hollowed center in the rear side of this casing21is a removable vertically long front retainer25that elastically holds plural substrates W horizontally at their front side periphery.

Each locking mechanism26includes a rotary plate27that is axled on the front side of casing21so as to be operated from the outside. A pair of top and bottom advancing/retracting plates that slide vertically outwards and inwards of casing21as rotary plate27rotates are coupled with the peripheral part of rotary plate27by means of arc-shaped slots, pins and the like. An engaging claw that passes through the peripheral wall of casing21to fit into engagement hole13of container body10is swayably coupled and supported at the distal end of each advancing/retracting plate.

A pair of supporting structures30are formed on both side walls by insert molding when container body10is molded, and function to array plural substrates W stored in container body10with a predetermined pitch in the vertically direction by horizontally supporting each substrate W at both left and right sides. As shown inFIGS. 6 to 11, each supporting structure30is formed including a supporting wall31integrated with the side wall of container body10, a plurality of supporting pieces34arrayed vertically on supporting wall31with a predetermined pitch, plural sections of a contact layer37laminated on the exposed area of part of supporting wall31and each supporting piece34and plural sections of a contact layer40formed on each supporting wall31.

In the thus constructed supporting structure30, as shown inFIGS. 9 to 11, the peripheral portions of boundary6between part of supporting wall31and contact layer37, of boundary6between each supporting piece34and contact layer37and of boundary6between supporting wall31and each contact layer40are each formed with tapering thin projected piece5, and the tapering inclined angle θ of each thin projected piece5is specified to range from 5° to 40°, preferably 10° to 30°, and more preferably 15° to 20° while the length L of inclined surface7forming boundary6is specified to range from 0.4 to 5.0 mm.

Supporting wall31and plural supporting pieces34are molded of the first molding material made of polycarbonate or the like which is excellent in impact resistance, heat resistance and water resistance while plural sections of contact layer37and contact layer40are molded of the second molding material made of polybutylene terephthalate or the like which has surface smoothness, low abrasiveness and dimensional stability. Accordingly, supporting wall31and plural supporting pieces34form first molding part1, and plural sections of contact layer37and contact layer40form second molding part3.

Supporting walls31are formed in a vertically long rectangular shape when viewed from front, and integrated by insert molding with the inner surface of the side walls when container body10is molded. The rear part33(the right side inFIGS. 6 and 8) of this supporting wall31is bent and inclined inwards of container body10with an inclined angle of 45° to 80°, so as to correspond to the shape of the rear part of the side wall of container body10that is curved inwards.

As shown inFIGS. 5 and 8, each supporting piece34is separately formed of a first supporting part35that is approximately horizontally projected inwards of container body10from the surface in a front part32of supporting wall31to oppose substrate W around the forward end of the side part (front end of the side part) from below through contact layer37and a second supporting part36that is approximately horizontally projected inwards of container body10from the surface in bent rear part33of supporting wall31to oppose substrate W around the tail end of the side part (rear end of the side part) from below through contact layer37. These first and second supporting parts35and36are arranged apart in the front-to-rear direction of container body10, or in the direction in which substrate W is put in and taken out.

As shown inFIG. 7, first supporting part35has an approximately semi-circular form, when viewed from top, having an approximately tapering section gradually thinner toward the distal end, and is positioned on the front side of container body10and covered with contact layer37, so that its thin front end part opposes the underside of substrate W at a position close to the front end from below through contact layer37. On the other hand, second supporting part36has a polygonal form smaller and narrower than first supporting part35, having an approximately tapering section gradually thinner toward the distal end, and is positioned on the rear side of container body10and covered with contact layer37, this contact layer37partly covering the rear part33surface of supporting wall31(seeFIG. 6).

As shown inFIGS. 7,9and10, plural sections of contact layer37are integrally laminated over the exposed areas of first and second supporting parts35and36and also over the rear part33surface of supporting wall31between plural second supporting parts36that are arranged vertically, in such a manner that the peripheral portions of boundaries6with first and second supporting parts35and36and the rear part33surface of supporting wall31are each formed with tapering thin projected piece5, wherein the tapering inclined angle θ of each thin projected piece5is specified to range from 5° to 40°, preferably 10° to 30°, and more preferably 15° to 20° while the length L of inclined surface7forming boundary6is adjusted to range from 0.4 to 5.0 mm.

Contact layer37covering first and second supporting parts35and36is formed to have an approximately tapering hollowed section with a top surface38gradually inclined downward toward the distal end so as to support side periphery of substrate W. The thus formed top surface38of contact layer37is formed with such an inclination as to render an inverted circular cone that is concentric with the center of substrate W, as shown inFIG. 7, and functions to position substrate W utilizing its weight and restrict substrate W from rotating.

As shown in the same figure, a stepped portion39is formed in the thickness direction in top surface38of contact layer37that covers first supporting part35. This stepped portion39comes into contact with the side periphery of substrate W so as to restrain the substrate from popping out toward the open front of container body10. This stepped portion39is formed as high as the thickness dimension of substrate W, specifically 0.3 mm to 0.7 mm.

As shown inFIG. 6, plural sections of contact layer40are arrayed vertically with a predetermined pitch in the approximate center on the surface of each supporting wall31and positioned between first and second supporting parts35and36so as to come into contact with substrate W when it is taken in and out at its closest positions Wa to supporting walls31on both sides, thereby preventing abrasion and damage accompanied by contact of substrate W with supporting walls31.

As shown inFIGS. 6 and 11, each contact layer40is formed in a laterally long or vertically long rectangular shape when viewed from front with its peripheral portion of boundary6with the surface of supporting wall31formed with tapering thin projected piece5. The tapering inclined angle θ of each thin projected piece5is specified to range from 5° to 40°, preferably 10° to 30°, and more preferably 15° to 20° while the length L of inclined surface7forming boundary6is adjusted to range from 0.4 to 5.0 mm. Other portions are the same as in the above embodiment, so that description is omitted.

In the above, when container body10and supporting structures30are produced, first, supporting wall31of supporting structure30and plural supporting pieces34to be the base are integrally molded of the plasticized first molding material to form an intermediate article. This intermediate article is set in a mold (not shown) for molding plural sections of contact layer37and contact layer40, and the plasticized second molding material is charged into this mold to form plural sections of contact layer37and contact layer40, forming a complete supporting structure30.

During this molding, the peripheral portions of boundary6of supporting wall31with contact layer37, boundary6of each of first and second supporting parts35and36with contact layer37and boundary6of supporting wall31with each contact layer40are each formed with tapering thin projected piece5, wherein the tapering inclined angle θ of each thin projected piece5is specified to range from 5° to 40° while the length L of inclined surface7forming boundary6is set to range from 0.4 to 5.0 mm, it is hence possible to expect favorable fusing and joining without regard to the compatibility of the first and second molding materials. Accordingly, it is possible to form strong integration of supporting wall31with contact layer37, of first and second supporting parts35and36with contact layer37and of supporting wall31with contact layer40, without using high pressure and/or heat.

Thus, a molding of supporting structure30is completed, and this supporting structure30is inserted into a mold (not shown) for molding container body10. Then, the molding material for container body10is charged into this mold. Thereafter, the product is cooled and dismounted from the mold so as to complete container body10including supporting structures30on both the left and right sides.

According to the above configuration, even when the first and second molding materials are unfavorable for combination (e.g., combination of polycarbonate and polybutylene terephthalate, etc.) in view of joining, the peripheral portions of boundary6between supporting wall31and contact layer37and boundary6between each supporting piece34and contact layer37are each integrated by forming thin projected piece5so that it is possible to join properly and firmly. As a result, it is no longer necessary to reconsider the combination from the viewpoint of joining. Accordingly, it is possible to use two kinds of molding materials in combination properly, placing weight on performance, even though the two are poor in compatibility, hence it is possible to definitely meet different demanded properties of plural portions of supporting structure30.

Also, it is possible to reliably inhibit and prevent the interface between two kinds of molding materials from weakening in strength and the materials from peeling off from immersion of a surfactant and stress during washing or from vibration during usage and transportation. Further, since not only part of the periphery of boundary6is formed with tapering thin projected piece5but the whole periphery of boundary6is formed with tapering thin projected piece5, a markedly high strength can be obtained.

Further, since not the exposed area of supporting piece34but the inclined top surface38of contact layer37which is high in sliding performance will be in contact with substrate W, very smooth movement of substrate W can be expected without producing any trace at the positions of placement on substrate W. Accordingly, it is possible to prevent substrate W from being taken out incorrectly, hence prevent trouble and positively prevent substrate W from being marked and scratched. Moreover, since first and second supporting parts35and36are not formed of a one-piece plate, but are separated and arranged apart from each other, it is possible to lessen the contact area with substrate W, hence markedly reduce generation of particles.

Next,FIG. 12shows the second embodiment of the present invention. In this case, a projection50that comes in contact with the peripheral part on the undersurface of substrate W is formed on the top surface38of either the contact layer37that covers first supporting part35of each supporting structure30or the contact layer37that covers second supporting part36.

InFIG. 12, projections50that come in contact with the peripheral part on the undersurface of substrate W are formed on top surface38of the contact layer37that covers first supporting parts35on both left and right sides. Instead of this, projections50that come in contact with the peripheral part on the undersurface of substrate W may be formed on top surface38of the contact layer37that covers each of second supporting parts36.

Projection50maybe, for example an elongated linear piece that is integrated with top surface38of contact layer37and oriented in the radial direction of substrate W. Other portions are the same as in the above embodiment, so that description is omitted.

Also in the present embodiment, the same operational effect as in the above embodiment can be expected. In addition, since projections50of a small area come into contact with the undersurface of substrate W, it is obvious that the possibility of generation of particles can be markedly reduced by reducing the contact area.

Next,FIG. 13shows the third embodiment of the present invention. In this case, an interposed covering layer51of a material at least different from the second molding material is formed plate-like and integrated between each side wall of container body10and supporting wall31of each supporting structure30.

Each interposed covering layer51is thin molded of a molding material other than the second molding material, for example the first molding material or any other molding material. Other portions are the same as in the above embodiment, so that description is omitted.

Also in the present embodiment, the same operational effect as in the above embodiment can be expected. In addition, it is obvious that the structure can be integrated with the side wall of container body10after the second molding material is made not to be exposed to the exposed area of the first molding material.

Next,FIGS. 14 and 15show the fourth embodiment of the present invention. In this case, a plate-like shelf52is formed horizontally between, and apart from, first and second supporting parts35and36as supporting piece34of each supporting structure30.

Shelf52is molded of a predetermined molding material, and formed with its top formed at the same height of the surface of first and second supporting parts35and36, or lower than the height of the surface of first and second supporting parts35and36. If the same operational effect as that of the first and second supporting parts35and36is wanted, contact layer37of the second molding material is laminated over at least the top surface of the exposed area. The molding material of this shelf52is not particularly limited, but the first molding material is selected if contact with substrate W is wanted to avoid.

The bottom side or the undersurface of shelf52is positioned higher than the undersurface of first and second supporting parts35and36in order to avoid the pickup range narrowing when substrate W is picked up by automaton. Other portions are the same as in the above embodiment, so that description is omitted.

Also in the present embodiment, the same operational effect as in the above embodiment can be expected. In addition, it is obvious that when substrate W is inserted into container body10not automatically but manually, a wrong insertion of the substrate into adjacent supporting piece34(cross-slot) can be inhibited by shelf52.

Next,FIG. 16shows the fifth embodiment of the present invention. In this case, contact layer37is laminated over only the top surface of first and second supporting parts35and36as supporting piece34of each supporting structure30. Other portions are the same as in the above embodiment, so that description is omitted.

Also, in the present embodiment, the same operational effect as in the above embodiment can be expected. In addition, since of the exposed areas of first and second supporting parts35and36, contact layer37is laminated over at least the top surface, it is possible to reduce the lamination area of contact layer37, hence cut down the cost.

Next,FIGS. 17 and 18show the sixth embodiment of the present invention. In this case, instead of molding supporting piece34of each supporting structure30with the first molding material, supporting piece34of each supporting structure30and contact layer37are molded of the second molding material and integrated so that each supporting piece34supports substrate W.

The peripheral portion of boundary6between supporting wall31and supporting piece34is formed with tapering thin projected piece5in view of securing strength, and the tapering inclined angle θ of each thin projected piece5is specified to range from 5° to 40°, preferably 10° to 30°, and more preferably 15° to 20° while the length L of inclined surface7forming boundary6is specified to range from 0.4 to 5.0 mm. Other portions are the same as in the above embodiment, so that description is omitted.

Also in the present embodiment, the same operational effect as in the above embodiment can be expected. In addition, it is possible to expect to diversify the production method and configuration.

The process of the multicolor molding method of the above embodiments can be modified as follows. For example, the plasticized first molding material is charged into a mold so as to form first molding part1by injection molding. The mold is opened once and the turntable of the mold is rotated 180° while the first molding part1remains attached to the core side of the mold. The mold is closed and then filled with the plasticized second molding material so as to form second molding part3while at least part of the peripheral portions of boundaries6between first and second molding parts1and3is formed with thin projected pieces5to fuse and integrate them so as to produce a multicolor molding article having patterns of design characters, numerals, symbols and the like after dismounting.

Other than the methods of multicolor molding using the dedicated machine inducing the above two sets of injectors, for example a method of performing multicolor molding by attaching two sets of molds back to back around a vertical shaft and turning half a rotation about the vertical shaft, or a method of performing multicolor molding by placing sets of a cavity and core for the first molding and the second molding in a single mold set may be adopted as appropriate. Further, this multicolor molding method is further developed so as to increase the number of cylinders for forming molding articles and perform molding of some colors.

Also, in the above embodiments, linear boundaries6between first and second molding parts1and3were shown, but the boundary is not particularly limited to this. A wavy, triangular, rectangular, jagged, stepped, saw-toothed or other shaped boundary6may be used to increase the contact area and thereby obtain good joining. Further, though a substrate storage container of a front open box type was illustrated, but the substrate storage container is not particularly limited to this. For example, a substrate storage container of an open cassette having a top opening is also permitted. Moreover, as long as no hindrance occurs, supporting piece34may be formed as a flat plate having an approximately open V-shape when viewed from top, instead of being divided into first and second supporting parts35and36.

Also, though the peripheral portion of boundary6between each supporting piece34and contact layer37is formed with tapering thin projected piece5, the configuration is not particularly limited to this. For example, at least part of the peripheral portion of boundary6between an arbitrary supporting piece34and contact layer37may be formed with tapering thin projected piece5. Further, though supporting walls31are integrated with both the side walls of container body10by molding, supporting walls31may be integrated to the interior surface of the both side walls of container body10by fasteners such as screws, bolts, nuts and the like, or may be fixed by thermal welding, ultrasonic welding, laser welding or the like. It is also possible to fix supporting walls31to container body10or the bottom plate at its bottom by using concave-convex fitting or any other technique.

Further, when container body10is molded of the first molding material, first and second supporting parts35and36may be directly projected from the interior surface of the side walls of container body10instead of being formed from supporting walls31, and the peripheral portions of boundaries6of first and second supporting parts35and36with contact layer37may be each formed with tapering thin projected piece5, wherein its tapering inclined angle θ is specified within 5° to 40° while the length L of inclined surface7is set to range from 0.4 to 5.0 mm. Also, first supporting part35may be formed of a combined shape of an approximate triangle and an approximate semicircle when viewed from top.