JP2014015028A - Box type molding and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding that is suitable for a component part of a touch panel type display face that is used for a mobile phone terminal or the like.SOLUTION: A box type molding includes: a flat display part consisting of a transparent resin sheet; and a perimeter frame part consisting of an injection molding resin, wherein the perimeter frame part is performed by fusion integration with the flat display part at a perimeter of the flat display part, and strain is few. The box type formed part can be produced by fabrication that is performed in a state in which a temperature difference is disposed between a sheet fitting part in a metal mold and a perimeter frame part cavity part in which an injection molding resin is filled.

Description

  The present invention is a molded product suitable for a component of a touch panel type display surface used for a mobile phone terminal or the like, and a box type molded product in which a touch panel surface and a peripheral frame portion made of injection molded resin are fused and integrated, and It relates to the manufacturing method.

As a component part of a touch panel type display surface used for a mobile phone terminal or the like, a glass plate is bonded to a frame part made of injection molded resin with a double-sided adhesive tape or the like.
The reason for this is that a thinner touch panel surface is preferable from the point of response speed, etc., a thickness of a certain level or more is required from the point of strength, and a material with high elastic modulus is selected, and This is because scratch resistance and fingerprint wiping properties are also essential.

  On the other hand, resin molded bodies are used for housings of automobile interior parts such as instrument covers, home appliances, OA equipment, personal computers, tablet PCs, and small portable equipment. These molded products are appropriately used as decorative molded products integrated with a decorative sheet on which a design such as a metallic tone and a wood grain tone is formed.

As a method of integrating a molded body and a sheet having a specific function such as a decorative sheet, (1) As a specific function, a sheet having a hard coat layer or the like is formed by injection molding without any special molding. A method of attaching a sheet to a mold and injecting a molten resin to form an injection-molded body and at the same time a sheet to the molded body,
(2) A decorative sheet that enables thermoforming (vacuum forming, pressure forming, vacuum pressure forming, etc.) is processed into a specific shape by pre-forming, set in an injection mold, and molten resin is injected. And a method of forming an injection-molded body and integrating it with a preformed decorative sheet at the same time,
Etc. are used. Also,
(3) A method of coating the surface of the molded body (three-dimensional surface decoration molding) has also been proposed.

As the decorative sheet, for example, acrylic or PET resin is used, and a design layer is appropriately provided on the back surface of the hard-coated base material having a poor scratch resistance (soft) that can be bent three-dimensionally. A laminate of a protective layer such as a plastic resin sheet or an adhesive layer is used.
For example, Patent Document 1 discloses a decorative sheet in which a transparent acrylic resin sheet layer, a pattern printing ink layer, an ABS resin sheet layer, and an ABS resin backer layer are laminated in this order from the surface side. In Patent Document 2, decoration is applied to one surface of a multilayer film in which a layer made of methacrylic resin and acrylic rubber particles is laminated on the surface of a polycarbonate resin layer, and a thermoplastic resin sheet is laminated on the decorated surface. A decorative sheet or a decorative molded product obtained by injection-molding a thermoplastic resin on the decorative surface is disclosed.

In place of the decorative sheet, Patent Document 3 discloses an injection molded product using a sheet provided with a thermosetting or ultraviolet curable hard coat layer. Patent Document 4 discloses a hard coat having a layer formed by using a hard coat paint having a specific composition on one side of a base sheet or film, capable of thermoforming to some extent, and appropriately applying a design to the back side. A sheet or a decorative sheet is disclosed.
Such a decorative sheet or hard coat sheet is integrated with the injection molded body on the protective layer side (thermoplastic resin sheet side) to form a decorative or hard coat molded body. In the decorative molded body, a transparent resin sheet is disposed on the surface, and the design layer can be visually recognized through the transparent resin sheet. In addition, the hard coat generally used for the decorative sheet has a problem that it is easily damaged because an element that can be shaped three-dimensionally is required.

JP 2001-334609 A JP 2009-234184 A Japanese Patent Publication No. 4-40183 JP 2010-284910 A

An object of the present invention is to provide a molded product suitable for a component of a touch panel type display surface used for a mobile phone terminal or the like.
Specifically, the use of a transparent resin plate, for example, an aromatic polycarbonate sheet having hard coat layers on both sides, instead of a glass plate as a component of the touch panel type display surface is considered. In this case, although it is somewhat inferior in terms of scratch resistance, it can be used in the actual use range. However, in the case of a polymethylmethacrylate / aromatic polycarbonate multilayer sheet having a hard coat layer on both sides with a high surface hardness, for example, it cannot fall within the allowable warpage generation in an 85 ° C. and 85% RH test, There was a problem that the same usage as that of a conventional glass plate could not be adopted.

Therefore, from the standpoint of reducing warpage and obtaining a thin film with little deformation after the environmental test, a method in which it is fused and integrated with a peripheral frame portion made of injection-molded resin and reinforced with tension by the frame can be considered.
However, conventionally, there is no molded product in which an injection molding resin is integrated around the entire periphery of a member composed only of a hard-coated transparent resin sheet. This is because when a molded product is manufactured using the same resin sheet and injection molded resin by a normal insert molding method, a molded product without distortion is not obtained.
Therefore, when using the same resin sheet and injection molding resin, pay attention to the fact that the thermal expansion coefficient in the plane direction of the sheet is a smaller value, and in order to adjust this value, the injection molding resin Although an attempt was made to produce an injection molded product using a composition containing an inorganic filler, the same distortion was generated, and a good product was not obtained.

  The present inventor has further studied the relationship between the insert sheet and the molding material, the examination of the injection molding conditions, and the like. As a result, the temperature between the seat mounting portion and the peripheral frame portion cavitation portion filled with the injection molding resin is reduced. By using a mold that can be used even if there is a difference, molding with a temperature difference between the seat mounting part and the cavity part succeeded in obtaining a good molded product with no distortion. Based on this, the present invention has been completed.

That is, the present invention includes the following box-shaped molded products.
(1) A box having a flat display portion made of a transparent resin sheet and a peripheral frame portion made of injection-molded resin, and the peripheral frame portion is fused and integrated with the flat display portion around the flat display portion It is a molded product.
(2) The box-shaped molded product according to (1), wherein the flat display unit is a multilayer sheet having a hard resin layer on one side or both sides.
(3) A resin in which a hard resin layer is obtained by hydrogenating an aromatic ring of a copolymer obtained by copolymerizing an acrylic resin, a (meth) acrylic acid ester monomer, and an aromatic vinyl monomer (hereinafter referred to as a nucleus) The box-shaped molded product according to the above (2), which is selected from (hydrogenated MS resin).
(4) The box-shaped molded product according to (2) above, wherein the flat display portion has a thickness of 0.3 mm to 1.2 mm.
(5) The box-shaped molded product according to (1), wherein the flat display portion has a hard coat layer having a steel wool hardness of 2 or more on at least one side.
(6) The flat display unit has a hard coat layer on both sides, and has a printed layer on the entire periphery of the hard coat layer on the back surface side including the fusion region with the peripheral frame portion. It is a box-shaped molded product.
(7) The box-shaped molded product according to (1) above, wherein the peripheral frame portion is formed by blending 15 to 50 parts by weight of an inorganic filler with respect to 100 parts by weight of the injection molding resin.
(8) The box-shaped molded product according to (1) above, wherein the thermal expansion coefficient of the injection molded resin is 1.5 × 10 ^{−5 to} 6.5 × 10 ⁻⁵ (/ K).
(9) Deformation amount generated after leaving the flat display portion in an environment of 85 hours at a temperature of 85 ° C. and a humidity of 85% RH (relative humidity) for 120 hours and at 23 ° C. and a relative humidity of 50% for 4 hours. The box-shaped molded product according to (1) above, in which (amount of warpage) is 0.3 mm or less at an end portion of the flat display portion having a size of 120 mm × 65 mm.
(10) The box-shaped molded product according to (1), wherein the peripheral frame portion has a rising portion.

Moreover, this invention includes the following manufacturing methods.
(11) A transparent resin sheet constituting the flat display portion of the box-shaped molded product is mounted on the transparent resin sheet mounting portion of the mold, and the injection molding resin constituting the peripheral frame portion of the box-shaped molded product is used as the peripheral frame of the mold. This is a method for manufacturing a box-shaped molded article, in which a partial cavitating portion is filled and an injection molding resin is fused and integrated with the transparent resin sheet around the transparent resin sheet.
(12) In the mold, the box-shaped molded article manufacturing method according to (11) above, wherein the temperature of the transparent resin sheet mounting portion and the peripheral frame portion cavitation portion can be independently controlled.
(13) The method for producing a box-shaped molded product according to (12) above, wherein the temperature of the transparent resin sheet mounting portion of the mold is set 10 ° C. to 50 ° C. higher than the temperature of the peripheral frame portion cavitating portion.
(14) The method for producing a box-shaped product according to (11), wherein the transparent resin sheet has a hard coat layer having a steel wool hardness of 2 or more on at least one side.
(15) The transparent resin sheet has a hard coat layer on both sides, and has a printed layer on the entire circumference of the hard coat layer on the back surface side including the fused region with the injection molding resin. It is a manufacturing method of a box-shaped molded product.

  According to the present invention, a box type comprising a flat display portion made of a transparent resin sheet and a peripheral frame portion made of injection molded resin, and the peripheral frame portion is fused and integrated with the flat display portion around the flat display portion. Molded products can be provided.

It is sectional drawing which shows the metal mold | die for manufacturing the box-shaped molded product in this invention. It is sectional drawing which expands and shows the gap | interval of a metal mold | die. It is a whole perspective view which shows the box-shaped molded product in this invention. It is sectional drawing of the box-shaped molded product cut | disconnected by the A-A 'line | wire of FIG.

Hereinafter, the configuration and the like will be described with respect to the present invention.
1. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a box-shaped molded article suitably used for a component part of a touch panel type display surface. The box-shaped molded product has a flat display portion made of a transparent resin sheet and a peripheral frame portion made of injection-molded resin. The peripheral frame portion is fused and integrated with the flat display portion around the flat display portion. Thus, since the peripheral frame part is integrated only in the area around the flat display part, the molded product has a box shape (see FIG. 4 described later).
2. Transparent resin sheet First, as the transparent resin sheet constituting the flat display part (mainly touch panel type display surface, etc.), (1) a sheet using a transparent plastic material, (2) impact resistance and moderate heat resistance A multilayer sheet having a resin layer as a base layer and a hard resin layer formed on one or both sides thereof, and (3) those having a hard coat layer formed on one or both sides of the sheet of (1) or (2) above. It is done.
Moreover, in the transparent resin sheet (planar display part), the printing layer which has designability etc. is normally formed in the part corresponded around the touchscreen type | mold display surface.
The transparent resin sheet is usually processed into a desired insert sheet shape by punching, NC cutting, laser cutting, or the like.

  Here, as a transparent plastic material (above-mentioned (1)) of the transparent resin sheet used in the present invention, aromatic polycarbonate, amorphous polyolefin (alicyclic polyolefin), polyacrylate, polysulfone, acetylcellulose, Examples thereof include transparent resins made of polystyrene, polyester, transparent polyamide and the like. Of these, resins used for lenses are preferred, and examples include aromatic polycarbonate, (meth) acrylic resin, styrene-acrylic copolymer resin, hydrogenated styrene-acrylic copolymer resin, and transparent polyamide.

  As the aromatic polycarbonate sheet (PC), 2,2-bis (4-hydroxyphenyl) alkane or 2,2- (4-hydroxy-3,3) is used from the viewpoint of film strength, heat resistance, durability or bending workability. A polymer produced by a known method from a bisphenol compound typified by 5-dihalogenophenyl) alkane is preferable, and the polymer skeleton may contain a structural unit derived from a fatty acid diol or a structural unit having an ester bond. good. In particular, an aromatic polycarbonate derived from 2,2-bis (4-hydroxyphenyl) propane is preferred.

The alicyclic polyester resin used as a composition with an aromatic polycarbonate (PC) includes, for example, a dicarboxylic acid component represented by 1,4-cyclohexanedicarboxylic acid and a diol component represented by 1,4-cyclohexanedimethanol. , Obtained by a known method in which a small amount of other components are esterified or transesterified as necessary, and then a polymerization catalyst is added, the pressure in the reaction vessel is gradually reduced, and a polycondensation reaction is performed ( PCC).
Specific examples of alicyclic dicarboxylic acids or ester-forming derivatives thereof include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-decahydronaphthalene dicarboxylic acid. Examples include acid, 1,5-decahydronaphthalenedicarboxylic acid, 2,6-decahydronaphthalenedicarboxylic acid, 2,7-decahydronaphthalenedicarboxylic acid, and ester-forming derivatives thereof.

  The polyamide resin of the transparent resin sheet used in the present invention is known as a transparent polyamide resin for lenses, for example, a range of a heat distortion temperature of 100 to 170 ° C., which is an index of heat resistance, an aromatic polyamide resin, Examples thereof include alicyclic polyamide resins, aliphatic polyamide resins, and copolymers thereof. The alicyclic polyamide resin is preferable from the balance of mechanical strength, chemical resistance, transparency, etc., but two or more polyamide resins may be combined. Examples of such polyamide resins include, but are not limited to, GLILAMIDTR FE5577, XE 3805 (manufactured by EMS), NOVAMID X21 (manufactured by Mitsubishi Engineering Plastics), and Toyobo Nylon T-714E (manufactured by Toyobo).

  The (meth) acrylic resin is, for example, a homopolymer of various (meth) acrylic esters represented by polymethyl methacrylate (PMMA) or methyl methacrylate (MMA), or PMMA, MMA and one or more other single monomers. It may be a copolymer with a body, and a mixture of a plurality of these resins may also be used. Among these, (meth) acrylates having a cyclic alkyl structure excellent in low birefringence, low hygroscopicity, and heat resistance are preferable. Examples of the (meth) acrylic resin as described above include, but are not limited to, Acripet (manufactured by Mitsubishi Rayon), Delpet (manufactured by Asahi Kasei Chemicals), and Parapet (manufactured by Kuraray).

  Among these, as the resin used as the base material layer of the above (2), aromatic polycarbonate and the like are mentioned as representative examples, and the hard resin layer formed on one side or both sides is an acrylic resin, ( A resin obtained by hydrogenating an aromatic ring of a copolymer obtained by copolymerizing a (meth) acrylate monomer and an aromatic vinyl monomer (nuclear hydrogenated MS resin), or 2,2- (4-hydroxy Aromatic polycarbonate resin copolymerized with -3-methylphenyl) alkane (composition of acrylic resin and aromatic polycarbonate resin having compatibility with aromatic polycarbonate resin copolymerized with acrylic monomer containing aromatic ring), etc. These are usually used as a composition containing an ultraviolet absorber because of improved weather resistance.

The sheet and multilayer sheet used in the present invention are usually produced by a (co) extrusion method, and the thickness of these sheets, that is, the flat display portion, is appropriately selected from a range of 0.3 mm to 1.2 mm, for example. .
In the case of a multilayer sheet, the thickness of the hard resin layer formed on one side or both sides is preferably selected from 0.03 mm to 0.1 mm. If it is too thin, the pencil hardness and the like are undesirably low, and if it is too thick, the effect of increasing the hardness is lost and the characteristic deterioration of the base sheet becomes large.
Then, in the extrusion process or after the extrusion, the sheet is appropriately hard-coated. In the application of the present invention, those excellent in wear resistance and fingerprint resistance (fingerprint wiping properties) are preferable. Usually, the hard coat layer is not required to be bent and can be used as long as it can be processed into an insert sheet shape, but from the viewpoint of productivity, a hard coat layer is particularly preferable.

As the material for the hard coat layer used in the present invention, known compounds that form a crosslinked film such as acrylic, silicon, melamine, urethane, and epoxy can be used. Among these, it is preferable that the formed hard coat layer has a pencil hardness of 4H or more and a steel wool hardness of 2 or more. Specifically, acrylic and silicon are exemplified as preferred, and acrylic is particularly preferred from the balance between processability and hardness.
The hard coat layer may be formed by an ordinary method, and is formed by a coating method such as a roll coating method, a dip method, or a transfer method. As the curing method, a known method such as ultraviolet curing, thermal curing, electron beam curing or the like can be used.

The acrylic hard coat layer is, for example, a crosslinkable polymerizable compound having at least two (meth) acryloyloxy groups (meaning acryloyloxy group and / or methacryloyloxy group, hereinafter the same) in the molecule, A residue that binds a (meth) acryloyloxy group is formed of a hydrocarbon or a derivative thereof, and the molecule may contain an ether bond, a thioether bond, an ester bond, an amide bond, a urethane bond, or the like.
Examples of the silicon-based hard coat layer include a thermosetting polyorganosiloxane composition appropriately blended with an ultraviolet absorber or the like. The polyorganosiloxane is a hydrolyzate and / or partial condensate obtained by hydrolyzing and condensing a normal organosilane represented by the general formula R ¹ nSi (OR ² ) (4-n). .

When using a transparent resin sheet as an insert sheet, a printing layer is usually formed around the flat display portion. For example, a transparent resin sheet having a hard coat layer on both sides is at least 2 mm, preferably about 20 mm, on the entire circumference of the hard coat layer on the back surface side including the fusion region with the peripheral frame portion formed by injection molding resin. Printing layer with a width of.
The insert sheet can be printed using polyester, polycarbonate, acrylic, and urethane printing inks, especially when there is a problem with adhesion to the hard coat surface such as plasma, ion etching, corona discharge, etc. It is possible to improve the adhesion by surface modification by treatment. Further, it is preferable to use a polyester-based ink so that it is not melted by the heat of the injection molding material.

Moreover, the thermal expansion coefficient (linear expansion coefficient) of the transparent resin sheet (insert sheet) in the planar direction is, for example, 6.3 × 10 ^{−5 to} 6.7 × 10 ⁻⁵ (/ K).

3. Flat display part A flat display part is formed with the above-mentioned transparent resin sheet. The flat display unit functions as a touch panel type display surface when, for example, a box-shaped molded product is incorporated in a mobile phone terminal or the like. In addition to the above-described transparent resin sheet, the flat display unit may include a touch panel sensor (an OCA-attached PET film with ITO wiring, a sheet with ITO wiring processed on the back surface of the transparent resin sheet), and the like.

  In the flat display part, it is preferable to suppress the generation of stress and strain, as will be described later. For this reason, for example, when a flat transparent resin sheet of 120 mm × 65 mm × (thickness 0.7 to 1.0) mm is used, the amount of warping at the end of the flat display portion in the manufactured box-shaped molded product However, it is 0.3 mm or less, preferably 0.2 mm or less, more preferably 0.1 mm or less. The size of the flat display unit is, for example, about 120 mm × 65 mm × (thickness 0.3 to 1.2) mm. The amount of warpage at the end of the flat display portion is measured, for example, after the flat display portion is left at room temperature for 24 hours, or the flat display portion is measured for 120 hours under conditions of 85 ° C. and 85% relative humidity. After the treatment, the measurement is carried out after leaving still in an environment of 4 hours at 23 ° C. and 50% relative humidity. Further, the resin having the lowest glass transition temperature in the resin constituting the flat display portion preferably has a glass transition temperature that is 10 ° C. higher than 85 ° C. that is the temperature during the heat treatment, that is, 95 ° C. or higher. .

4). Injection Molding Resin The injection molding resin is fused and integrated with the transparent resin sheet by injection molding around the flat display portion constituted by the transparent resin sheet. And injection molding resin forms a surrounding frame part. The injection molding resin used here is
(i) It can be heat-sealed with an insert sheet formed of the transparent resin sheet,
(ii) The linear expansion coefficient of the injection molding resin, particularly the linear expansion coefficient in the flow direction (MD) of the injection molding resin is optimal with respect to the value of the thermal expansion coefficient (linear expansion coefficient) in the planar direction of the insert sheet. Within a certain range,
But of course it is necessary. If the condition (i) is not satisfied, an integrally molded product cannot be obtained, and if the condition (ii) is not satisfied, stress generation due to a dimensional difference due to a temperature change is large, and the molded product is distorted. In other words, it is necessary to maintain a good balance between the linear expansion coefficient of the insert sheet and the linear expansion coefficient of the injection molding resin, and to suppress the warpage of the molded product that occurs when the insert sheet and the injection molding resin are integrated. It is.

First, the injection molding resin is formed by appropriately blending an inorganic filler as described below, but usually the same or the following heat-resistant molding material as the resin of the insert sheet is selected. And, it is preferable that at least the cut surface of the transparent resin sheet can be heat-sealed from the condition (i), and usually, by this condition, the injection molding resin is the same as the resin material of the above-mentioned transparent resin sheet, or A resin composition containing the same resin is selected.
It is also possible to select a different resin by pre-treatment with a material that can be heat-sealed or by primer treatment.
For example, when a transparent resin sheet having a double-sided hard coat layer is used as the insert sheet, if the injection-molded resin cannot be heat-sealed to the hard coat layer, it is usually used for printing that also serves as a design provided on the periphery. By selecting an ink component having a primer component, it is fused and integrated.

Next, from the condition (ii), it is usually preferable to use an injection molding resin containing an inorganic filler. As the inorganic filler, for example, glass fiber, talc, wollastonite, calcium carbonate whisker, potassium titanate whisker, carbon fiber, mica and the like can be used, preferably glass fiber, carbon fiber, wollastonite, or These mixed fillers and the like.
The thermal expansion coefficient of the inorganic filler is about 1/10 of that of the resin, and the thermal expansion coefficient of the injection molded resin blended with the inorganic filler is small, corresponding to the approximate volume% of the addition amount when the addition amount is small. Become.
Since the thermal expansion coefficient in the plane direction of the insert sheet by the transparent resin sheet is usually smaller than the value of the resin having no specific shape, the value of the thermal expansion coefficient of the injection-molded resin is equivalent to this value. Choose a smaller one.
For example, when an aromatic polycarbonate injection molding resin composition in which a multilayer sheet based on an aromatic polycarbonate is used as an insert sheet and an inorganic filler is blended, the inorganic filler is mixed in a range of about 10% by volume. The thing becomes a reasonable filling amount. As described above, the content of the inorganic filler is adjusted according to the thermal expansion coefficient of the transparent resin sheet and the injection molding resin, etc., but is 15 to 50 parts by weight, preferably 100 parts by weight of the injection molding resin. 20 to 40 parts by weight.

The thermal expansion coefficient (linear expansion coefficient) of the injection molded resin is adjusted according to the thermal expansion coefficient (linear expansion coefficient) in the planar direction of the transparent resin sheet (insert sheet), and the thermal expansion coefficient in the planar direction of the transparent resin sheet If the value is large, the value of the coefficient of thermal expansion of the injection-molded resin is adjusted to be large, but it is in the range of 1.5 × 10 ^{−5 to} 6.5 × 10 ⁻⁵ (/ K), preferably 1 It is .8 × 10 ^{−5 to} 6.3 × 10 ⁻⁵ (/ K).

  In addition to the inorganic filler, the injection molding resin may contain a colorant such as a pigment and a dye, an antioxidant, a stabilizer, a release agent, and the like.

5. Peripheral frame portion The peripheral frame portion is formed of the above-described injection molding resin and, if necessary, an inorganic filler. For example, the peripheral frame portion supports the touch panel type display surface (planar display portion) when a box-shaped molded product is incorporated in a mobile phone terminal or the like. For this reason, in the surrounding frame part, it is preferable that the rising part which extends toward the flat display part side and touches the flat display part is formed. By forming such a rising portion in the peripheral frame portion, the flat display portion can be held more firmly.

6). TECHNICAL FIELD The present invention also relates to a method for manufacturing a box-shaped molded product. In the manufacturing method of the present invention, first, a transparent resin sheet mounting part (for example, a movable side mold and a insertion piece) and a peripheral frame part cavitation part (for example, a fixed side mold and a insertion piece) can be independently temperature controlled. It is characterized by using a mold. And in the manufacturing method of the box-shaped molded article of this invention, it adjusts first so that the temperature by the side of a transparent resin sheet mounting part may become higher than the temperature by the surrounding frame part cavitating part side. Then, the transparent resin sheet is mounted on the transparent resin sheet mounting portion, and the heated injection molding resin is injected and filled into the peripheral frame portion cavitating portion.

  The resin that is injected and filled in the peripheral cavities, that is, the mold cavities that form the peripheral frames, is cooled at the mold surface, solidified at the melting point, and below the glass transition temperature in the mold close contact state. To be cooled. Thus, the peripheral frame portion fused to the mounting of the transparent resin sheet is formed by the injection molding resin. Thereafter, the outer peripheral portion of the peripheral frame portion shrinks, while the inner peripheral portion is in close contact with the mold, cooled to the mold temperature, taken out of the mold and cooled to room temperature, and a box-shaped molded product is manufactured. The And the dimensional change of this injection molding resin and a surrounding frame part is prescribed | regulated as a molding shrinkage rate mentioned later.

On the other hand, the insert sheet (transparent resin sheet) is heated and expanded simultaneously with the mounting to the mold, but closes the mold in a state where it does not rise to the temperature of the mounted mold. By closing the mold, the insert sheet also comes into contact with the peripheral frame portion cavitating portion side, and cooling by the peripheral frame portion cavitating portion side which is not heated to a higher temperature than the transparent resin sheet mounting portion side starts. Here, before the insert sheet is completely cooled, that is, before the temperature of the transparent resin sheet mounting part side and the temperature of the peripheral frame part cavitating part side reach a certain temperature, the peripheral frame part is injected with high temperature. Heated by filled resin. Then, the insert sheet is cooled to the mold temperature together with the injection filling resin, taken out of the mold and cooled to room temperature.
That is, the insert sheet is heated to a temperature higher than the mold temperature on the peripheral frame portion cavitation portion side, and is fused and integrated with the injection filling resin in a more expanded state. As a result, when the peripheral frame part cavitating part is taken out at the mold temperature, excessive shrinkage stress is not applied to the insert sheet from the peripheral frame part.
Therefore, it can be said that a good molded product that does not generate shrinkage stress that leads to the occurrence of strain can be produced. That is, the above-mentioned 4. The occurrence of distortion described in the column of the injection molding resin is the value of the thermal expansion coefficient (linear expansion coefficient) in the plane direction of the insert sheet (transparent resin sheet) and the value of the thermal expansion coefficient of the injection molding resin (linear expansion coefficient). Is suppressed to a certain extent, and the temperature of both at the time of injection molding is individually controlled.

As described above, the mold used in the present invention is capable of separately controlling the temperature of the transparent resin sheet mounting portion and the peripheral frame portion cavitation portion.
As described above, the temperature difference to be set is a temperature difference at which the insert sheet can be heated in a short time to a temperature higher than the temperature of the surrounding frame portion cavitating. be able to. From this point, it can be said that the injection resin is more preferable because the non-crystalline resin can produce a good molded product with a smaller temperature difference, and the control range is widened.
Further, by mounting the insert sheet in a state of being preheated and thermally expanded, a shorter molding cycle can be manufactured.
The above temperature difference varies depending on the expansion coefficient of the injection molding resin and the sheet, the presence or absence of preheating, etc., but the temperature of the transparent resin sheet mounting part of the mold is higher than the temperature of other parts including the peripheral frame part cavitating part. It sets so that it may become 10 degreeC or more, for example, 15 degreeC-50 degreeC high, Preferably 20 degreeC-40 degreeC high.

As an injection molding machine, AD-110 manufactured by Nippon Steel Works was used, and a mold 10 (see FIG. 1) was used to manufacture a box-shaped molded product as follows.
The mold 10 includes a resin injection side block 12, a sheet side block 14, and an intermediate block 16 that are members independent of each other. In the resin injection side block 12, a resin injection port 12M for injecting resin and a flow path 12F through which the resin passes are formed. On the other hand, in the sheet side block 14, a sheet mounting portion 14S (transparent resin sheet mounting portion) on which the transparent resin sheet (insert sheet) 20 is mounted is formed.

  And in the state (refer FIG. 1) where the sheet | seat side block 14 and the intermediate | middle block 16 were combined, 14 A of clearance gaps are formed between both members. That is, a gap 14A having an outer shape of 120 mm × 75 mm is formed between the seat-side block 14 and the central member 16C of the intermediate block 16 in a combined state, and the maximum height 14H of the gap 14A is 4 mm. A sheet mounting portion 14S is provided at the center of the gap 14A, and the size of the sheet mounting portion 14S is 118 mm × 73 mm × 1 mm.

  Further, a mold cavitation portion 14C (peripheral frame portion cavitation portion) is provided around the sheet mounting portion 14S, that is, at the outermost peripheral portion of the gap 14A. In the mold cavity portion 14C, as shown in FIG. 2, there is formed a hole portion 141C for storing a resin having a length of about 120 mm × width 2 mm × height 4 mm in the depth direction of FIG. A protruding hole 142C having a size of about 120 mm × width 2 mm × thickness 0.5 mm, which is an area overlapping with the mounting portion 14S, is formed.

  In the mold 10, the temperature can be adjusted independently for each block. For this reason, by adjusting the temperature of the sheet side block 14 and the temperature of the intermediate block 16, the temperature of the sheet mounting portion 14 </ b> S and the temperature of the mold cavity portion 14 </ b> C adjacent to the intermediate block 16 can be adjusted independently. It is possible to control.

  The transparent resin sheet 20 was created as follows. That is, a 1 mm thick multilayer sheet having a hard coat with a pencil hardness of 4H on the front side and a pencil hardness of F on the back side (layer structure: hard coat / polymethyl methacrylate / polycarbonate / hard coat: HC / PMMA / PC / HC, product Name: Iupilon sheet MR58, manufactured by Mitsubishi Gas Chemical Co., Ltd.), punching out a sheet having a printed pattern of size 118 mm × 73 mm, width of 4 mm on the back surface of the outer periphery of 118 mm, and width of 12 mm on the back surface of the periphery of 73 mm A transparent resin sheet 20 was obtained.

The thermal expansion coefficient (linear expansion coefficient) of the transparent resin sheet 20 was measured based on ISO-11359-2. The value of the coefficient of thermal expansion of the transparent resin sheet 20 measured in this way was 6.5 × 10 ⁻⁵ (/ K).

The printed pattern was formed by silk screen printing using a polyester-based ink (trade name; IPX-HF, Teikoku Ink Manufacturing Co., Ltd.). Further, a primer coat (trade name; IMB binder, manufactured by Teikoku Ink Manufacturing Co., Ltd.) was formed on the print. The peel strength was 25/25 in the cross cut test.
Moreover, pencil hardness is based on JISK5600-5-4.
Evaluation of steel wool hardness 4 or more was performed as follows using # 0000 steel wool.
Steel wool hardness 1: No flaw in 15 round trips with a load of 1000 g.
Steel wool hardness 2: No more than 3 scratches with a load of 1000 g.
Steel wool hardness 3: No more than 10 scratches at a load of 1000 g.

Using the injection molding material (resin) having the resin composition described in Table 1 below and the transparent resin sheet 20 described above, a box-shaped molded product 30 (see FIG. 3) was manufactured as follows.

  The box-shaped molded product 30 includes a flat display portion 32 formed by the transparent resin sheet 20 and a peripheral frame portion 34 formed by injection molding resin. The peripheral frame portion 34 is fused and integrated with the flat display portion 32 on the back surface 32B and the side surface 32S of the substantially rectangular flat display portion 32 (a box-shaped molded product cut along the line AA ′ in FIG. 3). (See FIG. 4 which is a sectional view of 30). The peripheral frame portion 34 is fused to the peripheral region 32R and the side surface 32S over the entire periphery of the back surface 32B of the flat display portion 32. The molded product 30 having such a box shape is suitable for use as a component of a touch panel type display surface, for example.

  In addition, on the back surface 32B side of the flat display portion 32, that is, the side including the fusion region 32R where the peripheral frame portion 34 is fused, printing with a width of 5 mm is performed on the hard coat layer around the entire flat display portion 32. A layer 32P is formed. In FIG. 3, since the flat display portion 32 is transparent, a state where the printed layer 32P formed on the back side 32B side is visible from the front surface 32A side is shown. Further, as shown in FIG. 4, the peripheral frame portion 34 is formed with a rising portion 34 </ b> P that extends toward the flat display portion 32 and contacts the fusion region 32 </ b> R and the side surface 32 </ b> S of the flat display portion 32. By forming the rising part 34 </ b> P, the flat display part 32 is firmly held by the peripheral frame part 34.

  Next, the injection molding material will be described with reference to Table 1 above. In Example 1, a material having a weight ratio of 7: 3 between PC (polycarbonate) and ABS (Iupilon TMB1615), and in Example 2, a material containing 80% by weight of PC and 20% by weight of glass fiber (GF / inorganic filler) (Iupilon GS2020MKR). In Comparative Example 1, a material containing only PC (Iupilon H3000), and in Comparative Example 2, a material containing 90% by weight of PC and 10% by weight of glass fiber (GF) (Iupilon GS2010MKR, both of which are manufactured by Mitsubishi Engineering Plastics Co., Ltd.) Were used respectively. In Comparative Examples 3 to 5, the same injection molding material as in Example 1 was used.

In the manufacture of the box-shaped molded product 30, the temperature of the mold 10 was set to a predetermined value shown in Table 2, respectively. That is, in Examples 1 and 2 and Comparative Example 1, the temperature of the sheet side block 14 was set to 85 ° C., and the temperature of the intermediate block 16 was set to 50 ° C. Further, in Comparative Example 2, the temperature of the seat side block 14 is set to 85 ° C., the temperature of the intermediate block 16 is set to 80 ° C., and in Comparative Examples 3 to 5, the temperatures of the seat side block 14 and the intermediate block 16 are equal. Alternatively, the sheet side block 14 is set to have a lower temperature than the intermediate block 16. The resin temperature in Table 2 indicates the temperature of the injection molding material (resin) immediately before being injected into the resin injection side block 12 from the resin injection port 12M of the mold 10.

  The shape of the flat display part 32 of the box-shaped molded product 30 of Examples 1 and 2 and Comparative Examples 1 to 5 manufactured in this way was measured, and the results are shown in Table 2. Here, the size of the flat display portion 32 is 120 mm × 65 mm × 1.0 mm, and the amount of warping at the end portion after the deformation is based on the flat surface before the deformation of the flat display portion 32 (the flat surface of the insert sheet 20). (Mm) was measured. The initial value of the amount of warpage in Table 2 was measured after the flat display units 32 of the examples and comparative examples were allowed to stand at room temperature for 24 hours, and the values after wet heat were measured for the flat display units 32 of the examples and comparative examples. The measurement was carried out after heating for 120 hours under conditions of 85 ° C. and 85% relative humidity, and further for 4 hours under conditions of 23 ° C. and 50% relative humidity.

  As shown in Table 2, in Examples 1 and 2, the warpage amount after the initial stage and after wet heat was 0.30 mm or less, and good results were obtained. For this reason, in the flat display part 32 of the box-shaped molded product 30 of Example 1 and 2, it can be said that the produced stress and distortion were suppressed. On the other hand, in Comparative Example 1, since the warpage amount at the initial stage and after the wet heat was a large value of 3 mm or more, it can be said that a large stress and distortion occurred in the flat display portion.

Between Examples 1 and 2 and Comparative Example 1, the mold temperature at the time of molding was equal and the same transparent resin sheet 20 was used. It can be said that this is due to the difference in the composition of the material (resin) and the coefficient of thermal expansion (see Table 1). That is, in Examples 1 and 2, the linear expansion coefficient in the flow direction (MD) of the injection molding resin is 2.7 or 2.8 × 10 ⁻⁵ (/ K), whereas in Comparative Example 1, the flow is It can be said that the latter warp amount increased mainly due to the linear expansion coefficient in the direction (MD) being 6.5 × 10 ⁻⁵ (/ K). For this reason, when forming the box-shaped molded product 30 using the transparent resin sheet 20 whose linear expansion coefficient value is 6.5 × 10 ⁻⁵ (/ K), it is approximately 2.7 to 2.8 × 10. ^It can be said that it is preferable to use an injection molding material (resin or resin and filler) having a linear expansion coefficient in the flow direction (MD) of about ⁻⁵ (/ K). In Example 2 and Comparative Example 1, the values of linear expansion coefficient in the perpendicular direction (TD) are approximate (6.2 × 10 ⁻⁵ (/ K) and 6.6 × 10 ⁻⁵ (/ K). )) However, the values of the linear expansion coefficients in the flow direction (MD) are greatly different (2.7 × 10 ⁻⁵ (/ K) and 6.5 × 10 ⁻⁵ (/ K)), and compared with Comparative Example 1. Since Example 2 clearly shows good results, it was confirmed that the linear expansion coefficient in the flow direction (MD) is more important than the linear expansion coefficient in the perpendicular direction (TD).

Further, in Comparative Example 2, although the linear expansion coefficient value (4.0 × 10 ⁻⁵ (/ K)) in the flow direction (MD) is closer to Examples 1 and 2 than the value in Comparative Example 1, The amount of warpage was 2.5 (mm) and 2.6 (mm), which was clearly larger than Examples 1 and 2 of less than 0.3 (mm). This is because the mold temperature on the sheet side block 14 (see FIG. 1) side in Examples 1 and 2 was set higher by about 35 ° C. than the mold temperature on the intermediate block 16 side (cavity side). On the other hand, in Comparative Example 2, it is considered that both temperatures were set to substantially the same level.

  Thus, it is clearer that the mold temperature affects the amount of warpage of the flat display unit 32 when the results of Examples 1 and 2 are compared with the results of Comparative Examples 3 to 5. In these examples and comparative examples, as is clear from Table 2 above, there is a large difference in the amount of warpage even though the injection molding material having the same composition was used. That is, in Examples 1 and 2, it was less than 0.3 (mm), but in Comparative Examples 3 to 5, a large warpage of about 2.0 (mm) to 5.5 (mm) occurred.

  In Examples 1 and 2, the mold temperature (85 ° C.) on the sheet side (block 14 side) was set higher than the mold temperature (50 ° C.) on the cavity side (intermediate block 16 side). In Comparative Example 3, both temperatures were the same (85 ° C.). In Comparative Example 4, rather, the mold temperature (60 ° C.) on the sheet side was set lower than the mold temperature (85 ° C.) on the cavity side, and this tendency was remarkable in Comparative Example 5 (sheet side). (40 ° C.) and cavity side (80 ° C.)). If the sheet side is set to a higher temperature than the cavity side, the amount of warpage of the flat display unit 32 can be suppressed (Examples 1 and 2), and the comparative example having a greater tendency to set the sheet side to a lower temperature than the cavity side. That is, it can be said that the amount of warpage of the flat display portion 32 was large in the order of Comparative Example 5, Comparative Example 4, and Comparative Example 3.

  As is clear from the above, in Examples 1 and 2, the mold temperature on the sheet side (block 14 side) including the sheet mounting portion 14S on which the transparent resin sheet 20 is mounted was set high and mounted. In a state where the transparent resin sheet 20 is heated to a high temperature and expanded, the injection molding material and the melt are sufficiently cooled to a low temperature by a mold on the cavity side (intermediate block 16 side) set to a lower temperature than the sheet side. The amount of warpage could be suppressed by integrating the clothes.

  On the other hand, in Comparative Examples 3 to 5, the expansion of the transparent resin sheet 20 and the cooling of the injection molding material (resin) were not sufficiently performed as in the example, and both were fused and integrated, so that the flat display It can be said that the amount of warpage of the portion 32 has increased.

  As described above, the peripheral frame formed of the injection molding material by adjusting the temperature on the sheet side of the mold 10 to be higher than the temperature on the cavity side where the injection molding material (resin) is injected. It was confirmed that it was possible to prevent a large shrinkage stress from being applied to the transparent resin sheet 20 from the portion 34 and to suppress the occurrence of the shrinkage stress in the box-shaped molded product 30. Furthermore, as is clear from the results of the above-described Examples and Comparative Example 1, the expansion coefficient of the injection molding material, in particular, the linear expansion coefficient in the flow direction (MD) depends on the expansion coefficient of the transparent resin sheet 20. It has been clarified that the amount of warpage of the flat display unit 32 can be suppressed by adjusting the position of the flat display unit 32.

10 Die 14C Die Cavitation (Cavity Frame)
14S sheet mounting part (transparent resin sheet mounting part)
20 Insert sheet (transparent resin sheet)
30 Box-shaped molded product 32 Planar display part 34 Surrounding frame part

Claims (15)

  A box having a flat display portion made of a transparent resin sheet and a peripheral frame portion made of injection-molded resin, and the peripheral frame portion is fused and integrated with the flat display portion around the flat display portion Molded product.   The box-shaped molded product according to claim 1, wherein the flat display portion is a multilayer sheet having a hard resin layer on one side or both sides.   The hard resin layer is selected from an acrylic resin and a resin obtained by hydrogenating an aromatic ring of a copolymer obtained by copolymerizing a (meth) acrylic acid ester monomer and an aromatic vinyl monomer. The box-shaped molded product according to claim 2.   The box-shaped molded product according to claim 1, wherein the flat display portion has a thickness of 0.3 mm to 1.2 mm.   The box-shaped molded product according to claim 1, wherein the flat display part has a hard coat layer having a steel wool hardness of 2 or more on at least one side.   6. The box-shaped molding according to claim 5, wherein the flat display part has the hard coat layer on both sides, and has a printed layer on the entire hard coat layer on the back side including the fusion region with the peripheral frame part. Goods.   The box-shaped molded product according to claim 1, wherein the peripheral frame portion is formed by blending 15 to 50 parts by weight of an inorganic filler with respect to 100 parts by weight of the injection molding resin. The box-shaped molded article according to claim 1, wherein the thermal expansion coefficient of the injection-molded resin is 1.5 x ^{10-5 to} 6.5 x ^10-5 (/ K).   The amount of deformation generated after leaving the flat display part in a heat treatment at a temperature of 85 ° C. and a relative humidity of 85% for 120 hours and standing in an environment of 23 ° C. and a relative humidity of 50% for 4 hours is 120 mm × 65 mm. The box-shaped molded product according to claim 1, which is 0.3 mm or less at an end portion of the flat display portion.   The box-shaped molded product according to claim 1, wherein the peripheral frame portion has a rising portion.   A transparent resin sheet constituting a flat display portion of a box-shaped molded product is mounted on a transparent resin sheet mounting portion of a mold, and an injection-molding resin constituting a peripheral frame portion of the box-shaped molded product is attached to the peripheral frame portion of the mold A method for manufacturing a box-shaped molded product, in which a cavity portion is filled and the injection molding resin is fused and integrated with the transparent resin sheet around the transparent resin sheet.   The method for manufacturing a box-shaped molded product according to claim 11, wherein in the mold, the temperature of the transparent resin sheet mounting portion and the peripheral frame portion cavitating portion can be independently controlled.   The manufacturing method of the box-shaped molded product of Claim 12 which sets the temperature of the transparent resin sheet mounting part of the said metal mold | die 10-50 degreeC higher than the temperature of the said surrounding frame part cavitating part.   The method for producing a box-shaped molded product according to claim 11, wherein the transparent resin sheet has a hard coat layer having a steel wool hardness of 2 or more on at least one side.   15. The box-shaped molding according to claim 14, wherein the transparent resin sheet has the hard coat layer on both sides, and has a printed layer on the entire circumference of the hard coat layer on the back side including the fused region with the injection molding resin. Product manufacturing method.