JP2013203047A - Hollow molded body and method for manufacturing hollow molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow molded body with high hermetic properties, and a method for manufacturing the hollow molded body.SOLUTION: A hollow molded body 1 is manufactured by laser fusing a container 2 and a lid 3 for sealing the container 2. The container 2 and the lid 3 are injection molded bodies made of a forming material including a thermoplastic resin. The container and lid have gate marks 2x and 3x formed during injection molding. The thermoplastic resin is aligned in a flow direction of a melt condition and solidified. The gate mark 3x of the container 2 is located in a position outside the hollow molded body 1, the position excluding a region of 2/3 or less of a distance from the center of gravity based on a distance from the center of gravity of a shape of a bottom face of the container 2 to an outer periphery of the bottom face. The gate mark 3x of the lid 3 is located at a position excluding a region of 2/3 or less of a distance from the center of gravity of each face based on a distance from the center of gravity of each of upper and lower faces in plan view of the lid 3 to an outer periphery of each of the upper and lower faces in plan view.

Description

  The present invention relates to a hollow molded body and a method for producing the hollow molded body.

  2. Description of the Related Art Conventionally, a resin molded body (hereinafter sometimes referred to as a hollow molded body) that has a housing space and is hermetically sealed is known. As a specific example of such a molded body, a hollow package in which a component such as an electronic circuit is enclosed in an insulating container and sealed with a cap (lid) can be mentioned.

  As a method for producing such a hollow molded body, a method of integrating a container and a cap by laser welding is known (for example, see Patent Document 1).

JP 2004-235484 A

  In such a hollow molded body, high airtightness may be required in order to prevent the components enclosed inside from being damaged by moisture and oxygen in the atmosphere, and further improvement compared to conventionally known ones. It was sought after.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the hollow molded object which has high airtightness. It is another object to provide a method for producing such a hollow molded body.

  In order to solve the above problems, one embodiment of the present invention is a hollow molded body formed by laser welding a container and a lid that seals the container, and the container and the lid are formed of a thermoplastic resin. Injection moldings of materials, each having a gate trace at the time of injection molding, the thermoplastic resin has a property of being oriented and solidified in the flow direction of the molten state, and the gate trace of the container is the hollow It is a position that is outside the molded body, and is a position that excludes a region within two-thirds of the distance from the center of gravity based on the distance from the center of gravity of the shape of the bottom surface of the container to the outer periphery of the bottom surface. The gate trace of the lid is 3 minutes of the distance from the center of gravity of each surface on the basis of the distance from the center of gravity of the planar shape of the top and bottom surfaces of the lid to the outer periphery of the planar shape of each surface. Except for areas within 2 Providing a hollow molded body in position.

In one aspect of the present invention, it is desirable that the average thickness TB of the bottom of the container and the average thickness TW of the side wall of the container satisfy the following formula (I).
4TB ≧ TW> 3 / 4TB (I)

  In one aspect of the present invention, the shape of the bottom surface is a polygon, and the gate trace of the container is 6 minutes of the distance from the corner of the bottom surface to the adjacent corner of the container with the corner of the bottom surface as the center. The gate traces of the lid are located on the upper and lower surfaces of the lid from the respective corners to the adjacent corners of the lid in the same plane with the corners of the upper and lower surfaces as the center. It is in the area within 1/6 of the distance, and on the side surface of the lid, it is in the area within 1/6 of the distance from the ridge line connecting adjacent corners of the upper surface and the lower surface of the lid to the opposing ridge line. It is desirable.

  In one embodiment of the present invention, the outer shape is preferably a rectangular parallelepiped.

  In one aspect of the present invention, the thermoplastic resin is preferably a liquid crystal polyester.

  Another embodiment of the present invention includes a step of injection-molding a container and a lid using a forming material containing a thermoplastic resin having a property of being oriented and solidified in a flow direction in a molten state, and an opening of the container Closing the lid with the lid and laser welding the contact portion between the container and the lid.In the injection molding step, the container is moved from the center of gravity of the bottom surface of the container to the outer periphery of the bottom surface. A mold having a gate position set at a position excluding a region within two thirds of the distance from the center of gravity with respect to the distance, and at a position outside the hollow molded body in which the container is closed with the lid. The lid is formed by using the distance from the center of gravity of each surface relative to the distance from the center of gravity of the top surface and the bottom surface of the lid to the outer periphery of the shape of the planar view on each surface. Exclude areas within 2/3 Using a mold in which set the gate position to positions to provide a method of manufacturing a hollow molded body to injection molding.

  According to the present invention, a hollow molded body having high airtightness can be provided. Moreover, the manufacturing method of such a hollow molded object can be provided.

It is a schematic diagram which shows an example of the hollow molded object of this embodiment. It is explanatory drawing of the container and lid | cover which can manufacture the hollow molded object of this embodiment. It is a figure explaining the effect by the position of the gate mark of a container and a lid. It is a figure explaining the effect by the position of the gate mark of a container and a lid. It is a schematic diagram which shows the suitable position of the gate trace of the container which exhibits a rectangular parallelepiped shape. It is a schematic diagram which shows the suitable position of the gate trace of the lid | cover which exhibits a rectangular parallelepiped shape. It is a schematic sectional drawing of a container. It is a schematic sectional drawing of a lid | cover. It is a schematic diagram explaining the welding apparatus used for laser welding. It is process drawing of laser welding. It is a schematic diagram which shows the shape of the container shape | molded by the Example and the comparative example, and a lid | cover.

[Hollow molding]
The hollow molded body of the present embodiment is a hollow molded body formed by laser welding a container and a lid that seals the container, and the container and the lid are injection molded bodies of a forming material containing a thermoplastic resin. Yes, each of which has a gate mark at the time of injection molding, and the thermoplastic resin has a property of being oriented and solidified in the flow direction of the molten state, and the gate mark of the container is outside the hollow molded body. The position of the bottom surface of the container, excluding a region within two-thirds of the distance from the center of gravity on the basis of the distance from the center of gravity of the shape of the bottom surface of the container to the outer periphery of the bottom surface. Is a region within two-thirds of the distance from the center of gravity of each surface, based on the distance from the center of gravity of the top surface and the bottom surface of the lid to the outer periphery of the surface shape of each surface. In the excluded position That.
Hereinafter, it demonstrates in order.

  1A and 1B are schematic views showing an example of a hollow molded body of the present embodiment, in which FIG. 1A is an exploded perspective view, and FIG. 1B is a schematic cross-sectional view. As shown in FIGS. 1A and 1B, the hollow molded body 1 of the present embodiment has a container 2 and a lid 3 which are molded bodies molded by injection molding. In the hollow molded body 1 of the present embodiment, the container 2 and the lid 3 are joined using a laser welding method.

  The container 2 is a molded body having a housing space S surrounded by a bottom 21 and a side wall 22 intersecting the bottom 21 and having an opening 23 formed on one surface. The shape of the container 2 can be set as appropriate according to the shape of the components housed in the housing space S. For example, when a semiconductor element having a generally rectangular parallelepiped shape is accommodated in the accommodating space S, as shown in FIGS. 1A and 1B, the rectangular parallelepiped bottom 21 and the side wall 22 orthogonal to the accommodating space S are provided. Is preferably a rectangular parallelepiped shape. In addition, it is good also as a hollow molded object which has a column-shaped external shape and a polygonal column-shaped external shape whose bottom face shape is a polygon. Furthermore, a hollow molded body having an outer shape of a truncated cone or a polygonal truncated cone may be used.

  The container 2 contains a colorant that absorbs laser light and converts energy into heat. As this colorant, carbon black, monoazo dye, anthraquinone dye, perylene dye, phthalocyanine dye, nigrosine dye, titanium black, black iron oxide, yellow iron oxide, red iron oxide, cadmium yellow, nickel titanium yellow, strontium yellow, water content Examples thereof include chromium oxide, chromium oxide, cobalt aluminate, and ultramarine blue, and one or more kinds may be used. Among these, carbon black, titanium black, and black iron oxide are preferable because of high heat resistance.

  Such a colorant is preferably contained in an amount of 0.01 parts by mass or more and 10 parts by mass or less, and 0.05 parts by mass or more and 5 parts by mass or less with respect to the total amount (100 parts by mass) of the container 2. More preferably.

  Moreover, the container 2 may contain an inorganic filler, various additives, etc. in the range which does not impair the effect of this invention.

  Note that a terminal for connecting the accommodation space S and the outside of the container 2 can be embedded in the side wall 22 at the time of injection molding of the container 2. For example, it is possible to obtain a container 2 having external connection terminals by inserting a lead frame that has been processed into a terminal shape in advance into a mold and then performing injection molding.

  The lid 3 is a plate-like molded body having the same shape as the container 2 in plan view. In the figure, the lid 3 has a rectangular shape in plan view, like the rectangular container 2 in plan view. Further, on the side of the lid 3 facing the container 2, a convex portion 31 that fits into the opening 23 of the container 2 is provided at the center. In the figure, in accordance with the shape of the opening 23 of the container 2, the convex portion 31 also has a rectangular shape in plan view.

  In the present embodiment, the shape of the lid 3 is the same as the planar view shape of the container 2 and the shape of the opening 23, but the planar view shape of the container 2 and the lid 3. May be different. Moreover, the center part of the lid | cover 3 may be rising up and it may be depressed. Of course, a flat lid that does not have the convex portion 31 like the lid 3 shown in the figure may be used.

  The lid 3 may contain an inorganic filler, various additives, and the like as long as the effects of the present invention are not impaired.

  The container 2 and the lid 3 are in a state where the convex portion 31 of the lid 3 is fitted into the opening 23 of the container 2, and the periphery (periphery portion 32) of the top portion 24 of the side wall 22 of the container 2 and the convex portion 31 of the lid 3. ), And the contact portion is joined using a laser welding method. In the hollow molded body of the present embodiment, when the container 2 and the lid 3 are welded by the laser welding method, each part is melted and joined. Therefore, it is preferable to use a forming material having the same melting point or flow start temperature for the container 2 and the lid 3, and it is more preferable to use the same material except for the presence or absence of the colorant.

  As a material for forming the container 2 and the lid 3 of the present embodiment, a resin material having an aromatic ring in the main chain skeleton and a linear structure can be used. Such a resin material is easily oriented when flowing, but in the hollow molded body of this embodiment, such a resin material can be used to form a hollow molded body having high airtightness.

  Specific examples of resin materials that can be used include polycarbonate resins, aromatic polyamides, polyphenylene ether resins, polyphenylene sulfide resins, polysulfone resins, polyarylate resins, polyetherimide resins, polyethersulfone resins, polyetherketone resins, Liquid crystal polyester, polyamideimide resin, polyimide resin and the like can be exemplified, but among these, liquid crystal polyester is preferable because of good fluidity, heat resistance, rigidity and gas barrier properties.

(Liquid crystal polyester)
The liquid crystalline polyester that can be used as a material for forming the hollow molded body of the present embodiment is a liquid crystalline polyester that exhibits liquid crystallinity in a molten state, and is preferably melted at a temperature of 450 ° C. or lower. The liquid crystal polyester may be a liquid crystal polyester amide, a liquid crystal polyester ether, a liquid crystal polyester carbonate, or a liquid crystal polyester imide. The liquid crystal polyester is preferably a wholly aromatic liquid crystal polyester using only an aromatic compound as a raw material monomer.

As a typical example of liquid crystal polyester,
(I) An aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid, and at least one compound selected from the group consisting of an aromatic diol, an aromatic hydroxyamine, and an aromatic diamine are polymerized (polycondensed). (II) Polymerized from plural kinds of aromatic hydroxycarboxylic acids (III) At least one compound selected from the group consisting of aromatic dicarboxylic acids and aromatic diols, aromatic hydroxyamines and aromatic diamines (IV) Polyesters such as polyethylene terephthalate and aromatic hydroxycarboxylic acids are polymerized. Here, the aromatic hydroxycarboxylic acid, the aromatic dicarboxylic acid, the aromatic diol, the aromatic hydroxyamine, and the aromatic diamine are each independently replaced with a part or all of the polymerizable derivative. Also good.

Examples of polymerizable derivatives of a compound having a carboxy group such as an aromatic hydroxycarboxylic acid and an aromatic dicarboxylic acid include those obtained by converting a carboxy group into an alkoxycarbonyl group or an aryloxycarbonyl group (ester), carboxy Examples include those obtained by converting a group into a haloformyl group (acid halide), and those obtained by converting a carboxy group into an acyloxycarbonyl group (acid anhydride).
Examples of polymerizable derivatives of compounds having a hydroxy group such as aromatic hydroxycarboxylic acids, aromatic diols and aromatic hydroxyamines include those obtained by acylating a hydroxy group and converting it to an acyloxyl group (acylated product) ).
Examples of polymerizable derivatives of amino group-containing compounds such as aromatic hydroxyamines and aromatic diamines include those obtained by acylating an amino group and converting it to an acylamino group (acylated product).

  The liquid crystalline polyester preferably has a repeating unit represented by the following general formula (1) (hereinafter sometimes referred to as “repeating unit (1)”). The repeating unit (1) and the following general formula (2) ) (Hereinafter sometimes referred to as “repeat unit (2)”) and a repeat unit represented by the following general formula (3) (hereinafter referred to as “repeat unit (3)”). More preferably).

(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
(3) ^-X-Ar 3 -Y-
(In the formula, Ar ¹ is a phenylene group, a naphthylene group or a biphenylylene group; Ar ² and Ar ³ are each independently a phenylene group, a naphthylene group, a biphenylylene group or a group represented by the following general formula (4): Yes; X and Y are each independently an oxygen atom or imino group; one or more hydrogen atoms in Ar ¹ , Ar ² and Ar ³ are each independently substituted with a halogen atom, an alkyl group or an aryl group May be.)
(4) -Ar ⁴ -Z-Ar ^5-
(In the formula, Ar ⁴ and Ar ⁵ are each independently a phenylene group or a naphthylene group; Z is an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)

Examples of the halogen atom that can be substituted for the hydrogen atom in the group represented by Ar ¹ , Ar ^2, or Ar ³ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the alkyl group that can be substituted for the hydrogen atom in the group represented by Ar ¹ , Ar ^2, or Ar ³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group. , S-butyl group, t-butyl group, n-hexyl group, n-heptyl group, 2-ethylhexyl group, n-octyl group, nonyl group, n-decyl group, etc. 10 is preferable.

Examples of the aryl group that can be substituted for the hydrogen atom in the group represented by Ar ¹ , Ar ^2, or Ar ³ include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, and the like. Examples thereof include condensed aromatic groups such as a monocyclic aromatic group, 1-naphthyl group and 2-naphthyl group, and the carbon number thereof is preferably 6-20.

When the hydrogen atom of the group represented by Ar ¹ , Ar ² or Ar ³ is substituted with these groups, the number of each group is represented by Ar ¹ , Ar ² or Ar ³ , respectively. Independently, it is preferably one or two, more preferably one.

  Examples of the alkylidene group include a methylene group, an ethylidene group, an isopropylidene group, an n-butylidene group, and a 2-ethylhexylidene group, and the number of carbon atoms is preferably 1 to 10.

The repeating unit (1) is a repeating unit derived from a predetermined aromatic hydroxycarboxylic acid. As the repeating unit (1), Ar ¹ is a p-phenylene group (repeating unit derived from p-hydroxybenzoic acid), and Ar ¹ is a 2,6-naphthylene group (6-hydroxy-2). -Repeating units derived from naphthoic acid) are preferred.

The repeating unit (2) is a repeating unit derived from a predetermined aromatic dicarboxylic acid. As the repeating unit (2), Ar ² is a p-phenylene group (a repeating unit derived from terephthalic acid), Ar ² is an m-phenylene group (a repeating unit derived from isophthalic acid), Ar ² Is a 2,6-naphthylene group (a repeating unit derived from 2,6-naphthalenedicarboxylic acid), and Ar ² is a diphenyl ether-4,4′-diyl group (diphenyl ether- 4,4′-dicarboxylic acid-derived repeating units) are preferred.

The repeating unit (3) is a repeating unit derived from a predetermined aromatic diol, aromatic hydroxylamine or aromatic diamine. As the repeating unit (3), Ar ³ is a p-phenylene group (a repeating unit derived from hydroquinone, p-aminophenol or p-phenylenediamine), and Ar ³ is a 4,4′-biphenylylene group. Those (4,4′-dihydroxybiphenyl, 4-amino-4′-hydroxybiphenyl or repeating units derived from 4,4′-diaminobiphenyl) are preferred.

  The content of the repeating unit (1) is the total amount of all repeating units constituting the liquid crystal polyester (the substance of each repeating unit is obtained by dividing the mass of each repeating unit constituting the liquid crystal polyester by the formula weight of each repeating unit). The equivalent amount (mole) is obtained, and the total value thereof) is preferably 30 mol% or more, more preferably 30 to 80 mol%, still more preferably 40 to 70 mol%, particularly preferably 45 to 65. Mol%.

  The content of the repeating unit (2) is preferably 35 mol% or less, more preferably 10 to 35 mol%, still more preferably 15 to 30 mol%, based on the total amount of all repeating units constituting the liquid crystal polyester. Most preferably, it is 17.5-27.5 mol%.

  The content of the repeating unit (3) is preferably 35 mol% or less, more preferably 10 to 35 mol%, still more preferably 15 to 30 mol%, based on the total amount of all repeating units constituting the liquid crystal polyester. Most preferably, it is 17.5-27.5 mol%.

  For example, when the liquid crystalline polyester is composed of the repeating unit (1), the repeating unit (2), and the repeating unit (3), the content of the repeating unit (1) is 30 mol% or more and 80 mol% or less. The content of (2) is preferably 10 mol% or more and 35 mol% or less, and the content of the repeating unit (3) is preferably 10 mol% or more and 35 mol% or less.

  As the content of the repeating unit (1) increases, the liquid crystalline polyester tends to improve the melt fluidity, heat resistance, strength and rigidity. However, if the content is too large, the melting temperature and the melt viscosity tend to increase, which is necessary for molding. Temperature tends to be high.

  The ratio between the content of the repeating unit (2) and the content of the repeating unit (3) is expressed as [content of repeating unit (2)] / [content of repeating unit (3)] (mol / mol). The ratio is preferably 0.9 / 1 to 1 / 0.9, more preferably 0.95 / 1 to 1 / 0.95, and still more preferably 0.98 / 1 to 1 / 0.98.

  In addition, liquid crystalline polyester may have 2 or more types of repeating units (1)-(3) each independently. The liquid crystal polyester may have a repeating unit other than the repeating units (1) to (3), and the content thereof is preferably 10 with respect to the total amount of all repeating units constituting the liquid crystal polyester. The mol% or less, more preferably 5 mol% or less.

  The liquid crystal polyester preferably has, as the repeating unit (3), X and Y each having an oxygen atom, that is, a repeating unit derived from a predetermined aromatic diol. As the repeating unit (3), More preferably, X and Y each have only an oxygen atom. By doing in this way, liquid crystalline polyester tends to become low in melt viscosity.

  The liquid crystal polyester is preferably produced by melt polymerization of raw material monomers corresponding to the repeating units constituting the liquid crystal polyester and solid-phase polymerization of the obtained polymer (prepolymer). Thereby, high molecular weight liquid crystal polyester having high heat resistance, strength and rigidity can be produced with good operability. Melt polymerization may be carried out in the presence of a catalyst. Examples of the catalyst in this case include metals such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide. Compounds, nitrogen-containing heterocyclic compounds such as 4- (dimethylamino) pyridine, 1-methylimidazole and the like can be mentioned, and nitrogen-containing heterocyclic compounds are preferably used.

  The liquid crystal polyester has a flow initiation temperature of preferably 270 ° C. or higher, more preferably 270 ° C. or higher and 400 ° C. or lower, and further preferably 280 ° C. or higher and 380 ° C. or lower. The higher the flow start temperature, the easier it is to improve heat resistance, strength and rigidity. However, if the flow start temperature is too high, a high temperature is required for melting, heat deterioration during molding is likely, and viscosity during melting increases. The sex will be reduced.

The flow start temperature is also called the flow temperature or flow temperature, and the liquid crystal polyester is heated at a rate of 4 ° C./min under a load of 9.8 MPa (100 kgf / cm ² ) using a capillary rheometer. Is a temperature showing a viscosity of 4800 Pa · s (48000 poise) when extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, and is a measure of the molecular weight of the liquid crystalline polyester (Naide Koide, “ “Liquid Crystal Polymer—Synthesis / Molding / Application—”, CMC Co., Ltd., June 5, 1987, p. 95).

(Gate trace)
The container 2 and the lid 3 each have a gate mark at the time of injection molding at a position on the outside of the hollow molded body 1. In the container 2 shown in FIG. 1A, there is a gate mark 2x at the time of injection molding in the lower part of the outer surface 29 of the side wall and in the vicinity of the corner. The lid 3 has a gate mark 3x at the time of injection molding near the corner of the side surface 39. In the hollow molded body 1 of the present embodiment, the container 2 and the lid 3 having a gate mark at such a position can be used.

  In addition, as a container and a lid | cover for manufacturing the hollow molded object 1 of this embodiment, it is not limited to what has a gate mark in the position as shown in FIG. FIG. 2 is an explanatory view of a container and a lid capable of producing the hollow molded body 1 of the present embodiment, and is a view for explaining the position of the gate mark. 2A is a schematic perspective view of the container as viewed from the bottom surface side, FIG. 2B is a schematic perspective view of the lid as viewed from the top surface side, and FIG. 2C is a schematic perspective view of the lid as viewed from the bottom surface side. It is.

  As shown in FIG. 2 (a), in the container 2 constituting the hollow molded body 1 of the present embodiment, the gate mark is based on the distance L1 from the center of gravity G1 of the bottom surface of the container 2 to the outer periphery of the bottom surface 25. It is in a position excluding the area AR1 within 2/3 of the distance L1 from the center of gravity G1. In FIG. 2A, the area AR1 where the gate mark of the container 2 should not be located is colored.

Further, as shown in FIG. 2B, in the upper surface 33a of the lid 3 constituting the hollow molded body 1 of the present embodiment, the gate mark has a distance L2 from the center of gravity G2 of the upper surface 33a to the outer periphery of the upper surface 33a. As a reference, it is at a position excluding an area within 2/3 of the distance from the center of gravity G2. In FIG. 2B, the area AR2 where the gate mark of the lid 3 should not be located is shown in color.

  Further, as shown in FIG. 2C, in the lower surface 33b of the lid 3 constituting the hollow molded body 1 of the present embodiment, the gate mark extends from the center of gravity G3 of the lower surface 33b of the lid 3 to the outer periphery of the lower surface 33b. With the distance L3 as a reference, it is at a position excluding an area within 2/3 of the distance from the center of gravity G3. In FIG. 2C, the area AR3 where the gate mark of the lid 3 should not be located is colored.

  In addition, in the container 2 and the lid 3, when there is a gate mark at such a position, the container 2 and the lid 3 were injection molded using a mold having a gate corresponding to the position of the gate mark. It means that.

  3 and 4 are diagrams for explaining the effect of the position of the gate mark on the container and the lid. FIG. 3 is a schematic diagram showing a case where gate traces are present in the areas AR1, AR2 shown in FIG. 2, and FIG. 4 is a schematic diagram showing a case where gate traces are present outside the areas AR1, AR2 shown in FIG. It is. The container and lid shown in FIG. 4 correspond to those shown in FIG. 3 and 4, the flow of the molten resin at the time of molding is indicated by arrows.

  First, as shown in FIG. 3, when injection molding is performed using a mold in which a gate position (indicated by 2y in the figure) is set at the center of the bottom surface of the container 2A, the molten resin is radiated from the gate. After spreading, it flows toward the top 24A of the side wall 22A, for example, as indicated by an arrow denoted by α1. On the other hand, when injection molding is performed using a mold in which the gate position (indicated by reference numeral 3y in the figure) is set at the center of the upper surface 33A of the lid 3A, the molten resin spreads radially from the gate, for example, the arrow indicated by reference numeral β1. So as to flow toward the peripheral portion 32A.

  Then, as indicated by arrows α1 and β1, the flow direction of the resin at the time of molding is the top 24A of the container 2A and the peripheral part 32A of the lid 3A, which are portions where the container 2A and the lid 3A are welded. Many intersections will occur.

  The resin used as the forming material in the hollow molded body of the present embodiment is oriented and solidified in the flow direction of the resin when melted. Therefore, in the case of the gate position as shown in FIG. 3, the resin orientation directions of the top portion 24A of the container 2A and the peripheral portion 32A of the lid 3A are different from each other in the portion where the container 2A and the lid 3A are welded. Will be. The inventors have found that when the members in which the resin is in such an orientation state are welded together, the strength of the welded portion is difficult to be obtained, resulting in a hollow molded body that is easily damaged and has low airtightness. I found it.

  On the other hand, as shown in FIG. 4, when injection molding is performed using a mold in which the gate position is set at a position that becomes the gate mark 2x of the container 2, the molten resin has a diagonal angle (reference numeral 26) with respect to the gate. It flows toward. Then, most of the resin that flows in the vicinity of the top 24 of the side wall 22 flows along the top 24 in the surface direction of the top 24 as indicated by an arrow α2.

  Further, when injection molding is performed using a mold in which the gate position is set to the position of the gate mark 3x of the lid 3, the molten resin flows toward a corner (reference numeral 34) on the diagonal side with respect to the gate. Then, most of the resin that flows in the vicinity of the peripheral edge portion 32 flows along the outer periphery of the lid 3 as indicated by an arrow denoted by β2.

  Then, as indicated by arrows α2 and β2, the flow direction of the resin at the time of molding at the top 24 of the container 2 and the peripheral edge 32 of the lid 3, which is a portion where the container 2 and the lid 3 are welded, is as follows. Many portions in the same direction will occur. In such places, the orientation directions of the resins are aligned. When the inventors have welded the container 2 and the lid 3 in such a resin-oriented state, the strength of the welded portion is likely to be obtained, and as a result, a hollow molded body that is hard to break and has high airtightness is obtained. I found out that I can do it.

  FIG. 5 is a schematic diagram showing a suitable position of the gate mark of the container having a rectangular parallelepiped shape (that is, a suitable position of the gate position at the time of molding).

  As shown in FIG. 5, the container 2 has a gate trace of the container 2 within one-sixth of the distance from the corner 27 on the bottom surface 25 side to the adjacent corner, with the corner 27 on the bottom surface 25 side of the container 2 as the center. It is preferable that it exists in the area | region. In the figure, a region where the gate mark is preferably located in the container 2 is indicated by reference numeral 28. In addition, in FIG. 5, the width | variety, depth, and height of the container 2 are each shown with the code | symbol W, D, and H1.

  FIG. 6 is a schematic diagram showing a preferred position of the gate trace of the lid having a rectangular parallelepiped shape (that is, a preferred position of the gate position during molding).

  As shown in the figure, on the upper surface 33a and the lower surface 33b of the lid 3, the gate trace of the lid 3 is centered on the corner 35 on the upper surface 33a side of the lid 3 and the distance from the corner 35 on the upper surface 33a side to the adjacent corner. An area within one-sixth and within one-sixth of the distance from the corner 36 on the lower surface 33b side to the adjacent corner, centered on the corner 36 on the lower surface 33b side of the lid 3, and surrounded by an arc or elliptical arc It is preferable that it exists in the area | region. Furthermore, the gate trace of the lid is preferably in a region other than the contact portion between the container and the lid, from the viewpoint of improving airtightness.

  Further, on the side surface 39 of the lid 3, the gate trace of the lid 3 has a distance from the ridge line (for example, the ridge line indicated by reference numeral 37) connecting adjacent corners of the upper surface 33 a and the lower surface 33 b of the lid 3 to the opposite ridge line. It is preferable that it exists in the area | region within 1/6.

  In the figure, the region where the gate mark is preferably located on the lid 3 is indicated by the reference numeral 38. In FIG. 6, the width, depth, and height of the lid 3 are indicated by symbols W, D, and H2, respectively.

  In the container 2 and the lid 3, when there is a gate mark at these positions, it means that the container 2 and the lid 3 are injection-molded using a mold in which the gate is disposed at these positions. In such a molded body (container 2 and lid 3), the resin flow direction at the time of molding at the top portion 24 of the container 2 and the peripheral edge portion 32 of the lid 3, which are portions where the container 2 and the lid 3 are welded. Are generated in the same direction, and the orientation direction of the resin is easily aligned. Therefore, when the container 2 and the lid 3 are welded, the strength of the welded portion is easily obtained, and as a result, a hollow molded body that is hard to break and has high airtightness can be obtained. Further, when the resin is injected and molded from the vicinity of the corner as described above, if the outer shape of the target hollow molded body is a rectangular parallelepiped as in this embodiment, the resin is welded at the portion where the container 2 and the lid 3 are welded. It is preferable that the orientation directions are easily aligned.

  FIG. 7 is a schematic cross-sectional view of the container 2. The gate position is determined according to the split position of the injection mold. In the container 2 shown in the figure, it is the end portion of the bottom surface 25, the surface direction of the outer surface 29 of the side wall (symbol L), and the end of the bottom surface 25. It is possible to exemplify a gate at a position where the resin is injected in the bottom surface direction (symbol M), the same height as the surface of the bottom portion 21 on the side of the accommodation space S, and in the bottom surface direction (symbol N). Further, from the viewpoint of flowing the resin in the surface direction of the top 24 at the top 24 of the side wall 22, the gate is located at the same height as the top 24 and injecting the resin in the surface direction (reference numeral X) of the top 24. There may be.

In the container 2, it is preferable that the average thickness TB of the bottom portion 21 and the average thickness TW of the side wall 22 show a relationship represented by the following formula (I).
4TB ≧ TW> 3 / 4TB (I)

  TB and TW are preferably 4 TB ≧ TW ≧ TB. If TB and TW satisfy TW> 3 / 4TB, the weld line in the container 2 is less likely to be located at the bottom 21, and the weld line is located at the bottom 21 to prevent airtight leakage that is likely to occur. The orientation state can be obtained. Further, when 4TB ≧ TW, the container 2 is unlikely to warp.

  FIG. 8 is a schematic cross-sectional view of the lid 3. The thickness TF of the peripheral edge 32 is preferably 0.2 ≦ TF / LA ≦ 1 with respect to LA, where LA is the width of the top 24 of the side wall 22 shown in FIG. 7, and 0.2 ≦ TF / More preferably, LA ≦ 0.5. When TF / LA ≧ 0.2, the strength of the obtained hollow molded article is sufficient. When TF / LA ≦ 1, attenuation of the amount of light reaching the top 24 of the side wall 22 can be suppressed. This is because TF / LA ≦ 1 when the laser light transmitted through the peripheral portion 32 at the time of laser welding has a component that is partially scattered at the peripheral portion 32 and irradiated in a direction intersecting the beam axis of the laser light. This is because even if the light is scattered, the top portion 24 is likely to be irradiated before the laser light spreads.

In addition, it is preferable that the convex part 31 which does not irradiate the laser beam in the lid 3 has an average thickness TR of 0.8 ≦ TF / TR ≦ 1.2 with respect to the thickness TF of the peripheral part 32. When TF / TR ≦ 1.2, the weld strength and airtightness of the welded portion are easily obtained, and when 0.8 ≦ TF / TR, the occurrence of warpage at the lid 3 can be suppressed.
The hollow molded body of the present embodiment is configured as described above.

[Method for producing hollow molded body]
The method for producing a hollow molded body according to the present embodiment includes a step of injection-molding a container and a lid using a forming material containing a thermoplastic resin having a property of being oriented and solidified in a flow direction in a molten state, and the container Closing the opening of the container with the lid and laser welding the contact portion between the container and the lid, and in the injection molding step, the container is moved from the center of gravity of the bottom surface of the container to the bottom surface of the container. Based on the distance to the outer periphery, the gate position was set at a position excluding a region within 2/3 of the distance from the center of gravity and outside the hollow molded body with the container closed by the lid. From the center of gravity of the planar view shape of the upper surface and the lower surface of the lid to the outer periphery of the planar view shape of each surface as a reference, from the center of gravity of each surface More than two-thirds of the distance A position excluding the area in which injection molding using a mold in which set the gate position.

  First, as described above, the container and the lid are formed by injection molding from a gate set at a position excluding a predetermined region. Next, the obtained container and the lid are brought into contact with each other so that the opening of the container is closed with the lid, and then the contact portion is formed by laser welding.

FIG. 9 is a schematic diagram illustrating a welding apparatus used for laser welding.
The welding apparatus 100 shown in the figure has a mounting table 101 on which the container 2 and the lid 3 to be laser welded are mounted, a heat sink 102 that holds the container 2 and the lid 3 between the mounting table 101, and an opening 103a. And a frame body 103 that holds down the heat sink 102. A transparent member made of a light transmissive material may be fitted in the opening 103a of the frame 103.

  The mounting table 101 is a plate-like member formed using a material such as a metal material or an inorganic material.

  The heat sink 102 has a laser light transmittance of 50% or more, which will be described later, and a thermal conductivity of 1 W / mK or more. The heat sink 102 preferably has a laser light transmittance of 90% or more. Moreover, it is preferable in thermal conductivity being 5 W / mK or more. Examples of the material for forming the heat sink 102 include transparent alumina, transparent beryllia, transparent magnesium, quartz glass, sapphire, and silicon.

  The mounting table 101 is provided so as to be movable up and down by an elevator 104 such as a spring or a hydraulic cylinder. The mounting table 101 and the frame body 103 are connected by a plurality of (four in the figure) support columns 105. In the figure, the elevator 104 is shown as a hydraulic cylinder.

  The laser light source 106 that emits laser light is provided so as to be able to scan in the horizontal direction, and is provided so that laser light can be emitted in the direction of the mounting table 101 (downward). The laser light source 106 uses an optical mirror, an optical fiber, a lens, or the like to selectively irradiate a laser beam to a minute region or to irradiate the laser beam with a different focal length. It is preferable that the transmission path can be changed.

  Examples of the type of laser light emitted from the laser light source 106 include gas lasers such as dye lasers, excimer lasers, argon lasers, krypton lasers, helium-neon lasers, solid lasers such as ruby lasers and YAG lasers, and semiconductor lasers. . Among these, laser light having a wavelength in the range of 800 to 1200 nm is preferable because the container 2 and the lid 3 can be stably welded without deteriorating the container 2 and the lid 3.

  In the welding apparatus 100 shown in the figure, the mounting table 101 to which the elevator 104 is connected is moved up and down. However, if the separation distance between the mounting table 101 and the heat sink 102 can be relatively changed, Other configurations can also be employed. For example, the mounting table 101 may be fixed and the heat sink 102 and the frame 103 may be moved up and down.

FIG. 10 is a process diagram of laser welding.
First, as shown in FIG. 10A, a semiconductor element or the like is accommodated in the accommodation space S of the container 2 as necessary, and then the container 2 and the lid 3 are overlapped and placed on the placing table 101.

  Next, the mounting table 101 is raised by the elevator 104. As the mounting table 101 rises, the lid 3 comes into contact with the heat sink 102, and the container 2 and the lid 3 are sandwiched and pressed between the mounting table 101 and the frame body 103. Thereby, the container 2 and the lid | cover 3 contact | adhere and are fixed. The pressure at this time is preferably 10 MPa or less so as not to impair the shapes of the container 2 and the lid 3. An elastic member made of silicone rubber or the like may be sandwiched between the mounting table 101 and the container 2.

  Next, as illustrated in FIG. 10B, the laser light LB is irradiated from the laser light source 106 to the contact portion between the container 2 and the lid 3. The energy of the laser beam LB is preferably 100 W or less in order to suppress decomposition / deterioration and deformation of the container 2. The scanning speed of the laser light source 106 is preferably 2 mm / second or more.

  The laser beam LB passes through the lid 3 and is irradiated to the container 2. Since the container 2 contains a colorant that absorbs the laser beam LB and generates heat, the contact portion is heated when the contact portion of the container 2 with the lid 3 is irradiated with the laser beam LB. 3 melt together. Thereafter, the molten resin is cooled and solidified, whereby the hollow molded body 1 of the present embodiment in which the container 2 is sealed with the lid 3 can be obtained.

At that time, in the contact portion between the container 2 and the lid 3 of the present embodiment, since there are many portions where the orientation directions of the resin are aligned, the strength of the welded portion is easily obtained, and as a result, the hollow molding that is hard to break and has high airtightness. The body 1 can be obtained.
The manufacturing method of the hollow molded object of this embodiment becomes the above structures.

  According to the hollow molded body having the above configuration, a hollow molded body having high airtightness can be provided.

  Moreover, according to the above manufacturing method, the hollow molded object which has high airtightness can be manufactured easily.

  In addition, the hollow molded object of this embodiment can be used as a case for housing a semiconductor element by enclosing the semiconductor element in an internal housing space. In addition to the semiconductor element, it can also be used as a case for storing an electronic component in which a sensor such as an image sensor or an acceleration sensor, a vibrator, or the like is enclosed.

  Examples of the present invention will be described below. In addition, this invention is not limited to an Example.

[Examples 1-6, Comparative Examples 1-6]
Liquid crystalline polyester containing a colorant (Sumitomo Chemical, Sumika Super LCP E6808THF BZ, flow start temperature 306 ° C., decomposition start temperature 499 ° C.) is injection molded to form a container, and liquid crystal polyester containing no colorant (Sumitomo Chemical) Manufactured by Sumika Super LCP E6808THF Z, flow start temperature 306 ° C., decomposition start temperature 499 ° C.) was injection molded to form a lid. The shape of the container and the lid is the same as that shown in FIG.

  FIG. 11 is a schematic view showing shapes of containers and lids molded in Examples and Comparative Examples. 11A and 11B are a schematic perspective view and a cross-sectional view of the container, and FIGS. 11C and 11D are a schematic perspective view and a cross-sectional view of the lid.

The dimensions of the prepared container are 8.6 mm x 8.6 mm x 1.44 mm for the outer dimensions (Wa x Da x Ha), and 6.8 mm x 6.8 mm x 0.00 for the inner dimensions of the housing space (Wb x Db x Hb). It was 94 mm.
The dimensions of the lid are 9 mm x 9 mm square (Wc x Dc), the thickness of the inner convex part (Hc) is 0.35 mm, the thickness of the peripheral part (Hd) is 0.3 mm, and the width (Wd) is 1.2 mm. there were.

On the mounting table of the welding apparatus, the container and the lid are placed in a state where the container is closed with a lid, and the heat sink made of quartz glass is placed on the lid, and the container and the lid are energized by a spring. The heat sinks were brought into close contact with each other. Laser light (wavelength 940 nm, laser diameter 0.2 mm at the focus, while scanning at a speed of 10 mm / second from a laser oscillator (FD-200-50, manufactured by Fine Devices Co., Ltd.) at the contact portion between the container and the lid. The laser output was 9.7 W). At that time, scanning was performed while irradiating the center of the focus of the laser light so as to pass through the center line at the top of the side wall of the container.
Thereafter, the container and the lid were cooled to obtain a hollow molded body. A total of 10 hollow molded articles were produced.

  The hollow molded body was confirmed to be airtight by the following method (bubble leak test).

(Bubble leak test)
The hollow molded body was immersed in Fluorinert heated to 125 ° C., and the presence or absence of bubbles was confirmed in 1 minute. Those with a pass number of 0-3 are evaluated as “×”, those with a pass number of 4-6 are evaluated as “△”, those with a pass number of 7-10 are evaluated as “◯”, and those with a “×” are rejected. It was evaluated.

[Example 7]
A hollow molded body was produced in the same manner as in Example 1 except that the height (Ha) of the outer dimensions of the container was 1.19 mm, and hermeticity was evaluated.

[Example 8]
A hollow molded body was produced in the same manner as in Example 1 except that the height (Ha) of the outer dimensions of the container was 1.84 mm, and the airtightness was evaluated.

[Example 9]
A hollow molded body was produced in the same manner as in Example 1 except that the height (Ha) of the outer dimensions of the container was 2.14 mm, and hermeticity was evaluated.

In Examples 1-9 and Comparative Examples 1-6, the gate trace of the container was located in any one of the signs A to D shown in the figure. Specifically, the gate positions indicated by reference signs A to D were as follows. In the mold used for injection molding, the gate diameter was 0.3 mm.
A: The gate center is located on the vertical ridge line (reference numeral 200) of the container and is set to be 0.25 mm from the bottom surface of the container. B: The gate center is the intermediate position of the container side wall. (Position of the ridge line 200 to 1/2 Da) and the position of the gate set to be 0.25 mm from the container bottom surface C: the gate center is near the corner of the container bottom surface and from two sides The position of the gate set so that the distance is 0.7 mm D: The position of the gate set so that the center of the gate is the center of the bottom of the container

Moreover, in Examples 1-9 and Comparative Examples 1-6, the gate position of the lid | cover was located in either of the code | symbols I-III shown to a figure. Specifically, the gate positions indicated by symbols I to III were as follows. In the mold used for injection molding, the gate diameter was 0.2 mm.
I: The position of the gate set so that the gate center is on the vertical ridgeline (reference numeral 300) of the lid and is 0.15 mm above the reference plane indicated by reference numeral 310 in FIG.
II: The position of the gate that is set so that the center of the gate is the middle position of the lid side wall (position of the ridgeline 300 to 1 / 2Dc) and the position of 0.15 mm from the reference plane 310
III: Gate position set so that the center of the gate is the center of the top of the lid

  In Examples 1 to 9 and Comparative Examples 1 to 6, Table 1 shows the results of the bubble leak test for the obtained hollow molded bodies.

  As a result of the evaluation, as in Comparative Examples 1 to 6, either a molding condition (condition D) in which the gate mark is the center of the bottom surface of the container or a molding condition (condition III) in which the top surface of the lid is the center is used. The hollow molded body had low airtightness.

  On the other hand, as in Examples 1 to 9, the hollow molded body using the container gate traces in the conditions A to C and the lid gate position in the conditions I and II has high airtightness. I understood.

  Further, the hollow molded bodies of Examples 7 and 8 in which the thickness (TB) of the bottom of the container and the thickness (TW) of the side wall satisfy 4TB ≧ TW ≧ TB are hollow in Example 9 that does not satisfy this relationship. It turned out that it has airtightness higher than a molded object.

  From these results, it was confirmed that the hollow molded body of the present invention has high airtightness, and it was found that the method for producing a hollow molded body of the present invention can provide a hollow molded body with high airtightness.

DESCRIPTION OF SYMBOLS 1 ... Hollow molded object, 2 ... Container, 2x ... Gate trace, 3 ... Lid, 3x ... Gate trace, 21 ... Bottom part, 22 ... Side wall, 23 ... Opening part, 24 ... Top part, 25 ... Bottom, 27 ... Corner, 28 ... Area, 29 ... Outer surface, 31 ... Projection, 32 ... Peripheral part, 33a ... Upper surface, 35, 36 ... Corner, 37 ... Edge line, 38 ... Area, 39 ... Side, 100 ... Welding device, 101 ... Mounting table, 102 DESCRIPTION OF SYMBOLS ... Heat sink, 103a ... Opening part, 103 ... Frame, 104 ... Elevator, 105 ... Strut, 106 ... Laser light source, AR1 ... Area, AR2 ... Area, G1 ... Center of gravity, G2 ... Center of gravity, L1 ... Distance, L2 ... Distance, S ... Containment space

Claims (6)

A hollow molded body formed by laser welding a container and a lid for sealing the container,
The container and the lid are injection molded bodies of a forming material containing a thermoplastic resin, each having a gate mark at the time of injection molding,
The thermoplastic resin has the property of being oriented and solidified in the flow direction in the molten state,
The gate trace of the container is a position on the outside of the hollow molded body, and the distance from the center of gravity of the shape of the bottom surface of the container to the outer periphery of the bottom surface is set to 2/3 of the distance from the center of gravity. It is in a position excluding the area within
The gate trace of the lid is a third of the distance from the center of gravity of each surface on the basis of the distance from the center of gravity of the top view and the bottom surface of the lid to the outer periphery of the shape of the plan view on each surface. A hollow molded body in a position excluding a region within 2. The hollow molded body according to claim 1, wherein the average thickness TB of the bottom of the container and the average thickness TW of the side wall of the container satisfy the following formula (I).
4TB ≧ TW> 3 / 4TB (I) The shape of the bottom surface is a polygon;
The gate trace of the container is in a region within one-sixth of the distance from the corner of the bottom surface to the adjacent corner of the container centering on the corner of the bottom surface;
The gate trace of the lid is within one-sixth of the distance from the respective corners to the adjacent corners of the lid in the same plane, with the corners of the upper and lower surfaces being the center at the upper and lower surfaces of the lid. In the area,
The hollow molded body according to claim 1 or 2, wherein the side surface of the lid is in a region within one-sixth of the distance from the ridge line connecting adjacent corners of the upper surface and the lower surface of the lid to the opposing ridge line.   The hollow molded body according to any one of claims 1 to 3, wherein the outer shape is a rectangular parallelepiped.   The hollow molded body according to any one of claims 1 to 4, wherein the thermoplastic resin is a liquid crystal polyester. A step of injection-molding the container and the lid using a forming material containing a thermoplastic resin having the property of being oriented and solidified in the flow direction in the molten state;
Closing the opening of the container with the lid, and laser welding the contact portion between the container and the lid,
In the injection molding step, the container is located at a position excluding a region within two-thirds of the distance from the center of gravity with reference to the distance from the center of gravity of the bottom surface of the container to the outer periphery of the bottom surface, and Injection molding using a mold in which the gate position is set at a position on the outside of the hollow molded body closed with the lid,
With respect to the distance from the center of gravity of the plan view shape of the top and bottom surfaces of the lid to the outer periphery of the plan view shape of each surface, the lid is within two-thirds of the distance from the center of gravity of each surface. A method for producing a hollow molded body, wherein injection molding is performed using a mold in which a gate position is set at a position excluding an area.

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