JP2000127196A - Injection molding simultaneous painting sheet, injection molding simultaneous painting method, and molded product - Google Patents

Abstract

(57) [Problem] To provide a painting sheet with good adhesion and heat resistance even to a resin molded product having poor adhesion, such as a polyolefin resin, by an injection molding simultaneous painting method. SOLUTION: A sheet S for simultaneous painting with injection molding is obtained by forming a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer as a main component of a binder resin on a transparent base sheet 1 mainly containing an acrylic resin. And a pattern layer 2 to which a coloring agent is added, and an adhesive layer 3 mainly composed of a thermosetting urethane resin using a blocked isocyanate. There may be a primer layer 4 between the picture layer and the adhesive layer. Injection molding simultaneous painting is performed using this painting sheet to obtain a molded product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminating type painting sheet used in the simultaneous painting method of injection molding, which can be laminated on a resin molded product, particularly a resin molded product made of a polyolefin resin, with good adhesion. Sheet for
The present invention relates to a method for simultaneous painting by injection molding and a molded product using the sheet.

[0002]

2. Description of the Related Art Conventionally, molded products obtained by decorating the surface of a resin molded product have been used for various purposes. For example,
In the simultaneous injection molding and painting method disclosed in Japanese Patent Publication No. 0-19132 and the like, a molded article having a decorated surface is obtained by laminating and integrating a painting sheet on the surface of a resin molded product simultaneously with the molding thereof. When a molded article is obtained by such a simultaneous painting method for injection molding, an injection resin generally used is mainly an acrylic resin, an ABS resin, a polycarbonate resin, or a polymer blend thereof. Also, when decorating the surface of a resin molded product made of inexpensive polyolefin resin, a molded product without a pattern is prepared in advance, and the painted portion is subjected to a base treatment such as a primer treatment, and then a general process. In most cases, a desired molded product is obtained by painting using a hydraulic painting method, which is a typical painting method.

[0003]

However, general-purpose resins such as acrylic resin, ABS resin, polycarbonate resin, etc., listed as injection resins in the above-mentioned simultaneous molding method for injection molding, have good workability but high cost. There is a drawback to say. When using an inexpensive polyolefin resin such as a polypropylene resin as the injection resin and decorating the surface with the injection molding simultaneous painting method, the adhesive between the painting sheet and the resin molding is a modified acrylic resin converted to chlorinated polypropylene. In many cases, a material to which was added was used. However, the adhesive has a problem of heat resistance of adhesion. This is because the adhesive tends to flow due to the heat of pre-molding the painting sheet with the vacuum mold as the injection mold during the simultaneous painting with the injection molding, and the adhesive tends to flow, which adversely affects the adhesion of the painting sheet. The problem is that the adhesive is thermally degraded in the heat resistance test of the painted molded article, and the painting sheet is easily peeled off from the resin molded article.

[0004] Therefore, an object of the present invention is to provide a painting method using an acrylic resin having excellent transparency for a base material sheet, even in a resin molded product such as a polyolefin resin, which is difficult to adhere to in simultaneous painting by injection molding. The purpose of the present invention is to provide a sheet that can be laminated on a resin molded product with good adhesion heat resistance. Also,
An object of the present invention is to provide a simultaneous painting method for injection molding, which allows a painting sheet to be laminated on a resin molded product with good adhesion and heat resistance, and to provide such a molded product.

[0005]

In order to solve the above-mentioned problems, a sheet for simultaneous painting with injection molding according to the present invention comprises a transparent base sheet mainly composed of an acrylic resin and an acrylic resin and vinyl chloride-acetic acid. A mixture with a vinyl copolymer is used as a main component of a binder resin, a pattern layer to which a coloring agent is added, and an adhesive layer mainly containing a thermosetting urethane resin using a blocked isocyanate are formed in this order. Configuration. In this way, by using a thermosetting urethane resin using a blocked isocyanate for the adhesive layer,
Even for a resin molded product such as a polyolefin-based resin which is difficult to adhere to, a painting sheet using an acrylic resin having excellent transparency as a base sheet can be laminated with good adhesion heat resistance. In addition, although the urethane resin of the adhesive is a thermosetting type, it uses a blocked isocyanate, so the adhesive layer hardens too much during handling such as preservation of a painting sheet before painting at the same time as injection molding, and the adhesive strength is too high. There is no loss. In addition, in the simultaneous painting by injection molding, even when the painting sheet is heated and softened and preformed, the heat of the heating and softening may cause the adhesive layer to be excessively hardened and lose adhesive strength. Hateful. In addition, since the base sheet, the picture layer, and the adhesive layer are made of a specific resin, the coated sheet has good adhesion between the layers and can obtain an excellent coating feeling.

Further, the simultaneous painting method for injection molding of the present invention
The above sheet for simultaneous painting with injection molding, between a pair of molds,
After the adhesive layer side is inserted so as to face the resin to be filled, both molds are clamped, and the cavity formed by both molds is filled with the resin in a fluid state and solidified. A sheet for simultaneous painting with injection molding is adhered to the surface of the molded product,
After lamination, both molds were opened to obtain a molded product in which the sheet for simultaneous painting with injection molding was laminated on a resin molded product. As described above, since the molded article is molded using the above-mentioned sheet for simultaneous painting with injection molding, a molded article obtained by laminating and integrating the painted sheet with good adhesion and heat resistance can be obtained. In addition, a painted product having an excellent painting feeling can be obtained.

Further, the molded article of the present invention is a molded article in which the sheet for simultaneous painting with injection molding is laminated on the surface of a resin molded article made of a polyolefin resin by an adhesive layer. In this way, since the molded article is painted by the injection molding simultaneous painting sheet, as a result, the heat resistance of the adhesion of the laminated painting sheet to the surface of the inexpensive polyolefin resin molded article is obtained. This gives a painted molded article with good paintability and excellent paint feeling.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view illustrating an example of a sheet for simultaneous injection molding and painting according to the present invention, FIG. 2 is a conceptual diagram illustrating the method for simultaneous injection molding and painting according to one embodiment of the present invention, and FIG. It is sectional drawing which illustrates the form example of the molded article of FIG.

[Sheet for Simultaneous Painting with Injection Molding] The sheet for simultaneous painting with injection molding of the present invention is a transparent base material mainly composed of an acrylic resin, such as the sheet for simultaneous painting with injection molding S illustrated in FIG. A material sheet 1 is composed of a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer as a main component of a binder resin, a pattern layer 2 to which a coloring agent is added, and a thermosetting urethane resin using a blocked isocyanate ( Is a sheet having a configuration in which an adhesive layer 3 whose main component is an uncured material is laminated in this order. Alternatively, a configuration in which a primer layer 4 is further interposed between the pattern layer 2 and the adhesive layer 3 in addition to the above configuration, such as the sheet S for simultaneous painting with injection molding illustrated in FIG. This primer layer 4
Is preferably composed mainly of urethane resin.

(Substrate Sheet) The substrate sheet 1 is a transparent resin sheet made of a thermoplastic resin. As the thermoplastic resin, in the present invention, the transparency is excellent, and as a result, an excellent coating feeling can be imparted. It is mainly composed of acrylic resin.
As the acrylic resin, for example, polymethyl (meth)
Acrylic resin such as acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, methyl (meth) acrylate-styrene copolymer [where (meth) acrylate is acrylate or methacrylate Is used alone or as a mixture of two or more, and is used as a sheet of a single layer or a laminate of two or more layers. The base sheet may be colored and transparent in addition to colorless and transparent. In the base sheet, if necessary, a lubricant such as polyethylene wax, paraffin wax, silica, spherical α-alumina, a lubricant comprising particles such as flaky α-alumina, a benzotriazole, Various additives such as benzophenone-based, fine particle cerium oxide-based ultraviolet absorbers, hindered amine radical scavengers and other light stabilizers, plasticizers, stabilizers, colorants, etc.
It may be added for adjusting physical properties. Also, as a secondary material,
Resins other than acrylic resin may be added. The thickness of the substrate sheet is not particularly limited, but is generally 20 to 50.
It is about 0 μm.

(Picture Layer) The picture layer 2 is a layer for expressing a pattern such as a pattern or a character. The pattern of the pattern layer is arbitrary, for example, wood grain, stone grain, cloth grain, sand grain, geometric pattern,
This is a pattern consisting of characters, solid color, etc. The picture layer is basically not particularly limited except that the binder resin is made of a specific resin and a layer to which a coloring agent is added.
The picture layer is usually formed with a printing ink or a paint by a known printing method such as gravure printing or a known coating method such as gravure coating. In the present invention, the binder resin is mainly composed of a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer. An acrylic resin is used to improve the adhesion of the base sheet to the acrylic resin, and a vinyl chloride-vinyl acetate copolymer is mixed to enhance the printing (or coating) suitability and the molding suitability.

Here, the acrylic resin may be appropriately selected from the same ones listed for the base sheet, and may be methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, or the like.
Alkyl (meth) acrylates such as 2-ethylhexyl (meth) acrylate and octyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate,
An acrylic polyol obtained by copolymerizing a (meth) acrylate having a hydroxyl group in a molecule such as hydroxy-3-phenoxypropyl (meth) acrylate can also be used. As the vinyl chloride-vinyl acetate copolymer, those having a vinyl acetate content of about 5 to 20% by weight and an average degree of polymerization of about 350 to 900 are usually used. If necessary, a carboxylic acid such as maleic acid or fumaric acid may be further copolymerized with the vinyl chloride-vinyl acetate copolymer. In this way, by introducing a hydroxyl group or a carboxyl group into the acrylic resin, it reacts with the isocyanate group (after the block is released) in the adhesive layer to cause a urethane bond or the like, and the bond between the picture layer and the adhesive layer. Adhesive strength
Better. The mixing ratio of the acrylic resin and the vinyl chloride-vinyl acetate copolymer is about 1/9 to 9/1 (weight ratio) of the acrylic resin / vinyl chloride-vinyl acetate copolymer. In addition, as a sub-component resin, if necessary, other resins, for example, thermoplastic polyester resin, thermoplastic urethane resin, chlorinated polyethylene, chlorinated polyolefin and other chlorinated polyolefin and other resins are mixed. Is also good.

The coloring agent to be added to the picture layer is optional. That is, the colorant used in the printing ink or paint may be a known pigment or dye. For example, titanium white, red iron oxide, graphite, ultramarine, carbon black, isoindolinone, quinacridone, phthalocyanine blue, or the like may be used alone or as a mixture of two or more.

(Adhesive Layer) The adhesive layer 3 is a layer mainly composed of a thermosetting urethane resin using a blocked isocyanate. Of course, at the stage of the painting sheet, it is in an uncured state before complete curing. By using the above-mentioned thermosetting urethane resin, the heat resistance of the adhesion of the sheet for painting to the resin molded product which is a solidified injection resin can be improved. In particular, it is effective for a resin having a generally poor adhesion such as a polyolefin resin as a resin of a resin molded product. Of course, it is possible to adhere to a resin molded product made of a resin other than the polyolefin-based resin. Also, by using the above-mentioned thermosetting urethane resin, the adhesive is hardened before the adhesive layer is formed after the adhesive layer is formed, and the adhesive strength with the injection resin is insufficient. There is no problem that it will be. In addition, printing (or coating) suitability and molding suitability can be improved. In the adhesive layer, a resin other than the above-mentioned thermosetting urethane resin may be used in combination within a range as an auxiliary component. The resin used in combination is selected mainly in consideration of the adhesion to the injection resin.

The thermosetting urethane resin using the above-mentioned blocked isocyanate is a urethane resin whose curing progresses by heat, using an active hydrogen-containing compound such as a polyol which is capable of reacting with isocyanate as a main component and a blocking isocyanate as a curing agent. As the thermosetting urethane resin using the blocked isocyanate, a known material in the field of urethane resin can be used, and there is basically no particular limitation.

The blocked isocyanate is an isocyanate which is made inactive at room temperature by temporarily reacting an isocyanate group of the isocyanate with an active hydrogen compound (blocking agent) such as phenol or alcohol. Then, the blocking agent is dissociated by heating to activate the isocyanate group, and a curing reaction by the isocyanate is started. The thermosetting (starting) temperature depends on the dissociation temperature of the blocking agent, and the dissociation temperature can be changed depending on the type of isocyanate, the type of blocking agent, the type and amount of the dissociation catalyst, the presence or absence and properties of the reaction partner, and the like. The timing of the start of the thermosetting is (1) at the time of preforming the painting sheet (described later), (2) at the time of injection molding, or (3) after the molded article is taken out of the mold. In the case of (1), the thermosetting temperature is equal to or lower than the preheating temperature of the preforming and sufficiently higher than the room temperature. In the case of (2), the thermosetting temperature is equal to or lower than the temperature of the injection resin in contact with the painting sheet and higher than the room temperature. Is set to be sufficiently high, and in the case of (3), it is set to be lower than the heat resistance temperature of the painting sheet and the resin molded product and sufficiently higher than room temperature. In addition, even if the thermosetting temperature is too high, the sheet for painting or the resin molding itself may not have a high temperature from the viewpoint of heat resistance. Therefore, when the thermosetting temperature is in the range of 100 to 110 ° C., it is convenient for a sheet for painting or a general resin molded product.

Examples of the blocking agent include phenol, cresol, xylenol, p-ethylphenol, o-isopropylphenol, p-tert-butylphenol, p-tert-octylphenol, thymol, p-naphthol, p-nitrophenol and p-nitrophenol. −
Phenolic blocking agents such as chlorophenol, methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve, butyl cellosolve,
Alcohol blocking agents such as methyl carbitol, benzyl alcohol, phenyl cellosolve, furfuryl alcohol, and cyclohexanol; active methylene blocking agents such as dimethyl malonate, diethyl malonate, and ethyl acetoacetate; butyl mercaptan; thiophenol;
mercaptan-based blocking agents such as rt-dodecyl mercaptan, acetanilide, acetoanisidide, acetate amide, acid amide-based blocking agents such as benzamide, succinimide, imide-based blocking agents such as maleic imide, diphenylamine, phenylnaphthylamine, aniline,
Amine-based blocking agents such as carbazole, imidazole,
Imidazole blocking agents such as 2-ethylimidazole; urea blocking agents such as urea, thiourea and ethylene urea; carbamate blocking agents such as phenyl N-phenylcarbamate and 2-oxazolidone; and imine compounds such as ethyleneimine. Blocking agents, oxime blocking agents such as formaldoxime, acetoaldoxime, methyl ethyl ketoxime, and cyclohexanone oxime, and sulfite blocking agents such as sodium bisulfite and potassium bisulfite are included.

The blocking agent can be dissociated by heating without a dissociation catalyst.
Since a high temperature of 200 ° C or more is required, the dissociation temperature is set to 16
In order to lower the temperature to 0 ° C. or lower, it is preferable to use a dissociation catalyst. As the dissociation catalyst, conventionally known catalysts such as amines, organic compounds, and metal soaps are used.

The active hydrogen-containing compound capable of reacting with isocyanate, which is a main component of the urethane resin, includes a hydroxyl group,
A compound containing a carboxyl group or the like in the molecule is used, and among them, a polyol having two or more hydroxyl groups in the molecule is typical. For example, polyester polyols such as poly (ethylene adipate), poly (butylene adipate), poly (neopentyl adipate), poly (hexamethylene adipate), poly (butylene azelate), poly (butylene sebacate), polycaprolactone, polyethylene Oxides, polypropylene oxide, polyether polyols such as poly (tetramethylene ether), polycarbonate polyols such as poly (butylene carbonate) and poly (hexamethylene carbonate), acrylic polyols, urethane polyols, and the like.

The thickness of the adhesive layer may be appropriately determined according to the required physical properties and the like, but is usually about 1 to 100 μm. The method for forming the adhesive layer is not particularly limited,
Usually, the resin is formed as an ink or coating liquid composed of a resin liquid obtained by diluting the resin with a diluting solvent, by a known printing or coating means such as gravure printing or roll coating. Further, in the adhesive layer, in order to adjust and improve various physical properties such as printing (or coating) suitability of the ink (or coating liquid), if necessary, other auxiliary materials, for example, Various additives such as pigments may be added. Even if the adhesive layer is in a fluidized state or a tacky (non-fluidized) state at room temperature (normal temperature) in an uncured state, it can be used depending on the method of painting simultaneously with injection molding or the device of the apparatus. However, in general, a non-adhesive solid at room temperature in an uncured state is preferable. That is, the adhesive may adhere to the sheet clamp or the like during molding,
It is easy to handle without problems such as blocking when the sheet for painting is wound up in a roll shape. In order to obtain a non-adhesive solid adhesive layer at room temperature in the uncured state,
At least one of the base material and the curing agent in the adhesive component becomes a non-adhesive solid at room temperature (generally, an average molecular weight of 10,0
(Higher molecular weight of about 00 or more). The "room temperature" is a temperature at which the painting sheet is stored until the painting sheet is painted simultaneously with the injection molding.

(Primer Layer) The primer layer 4 is not essential, but is preferably provided when it is desired to further improve the adhesion between the picture layer and the adhesive layer. For example, when the thermosetting urethane resin of the adhesive layer is selected with an emphasis on the adhesion to the resin molded product, there is a case where the adhesion to the picture layer becomes insufficient. The resin of the primer layer 4 is basically not particularly limited, and may be appropriately selected according to the resin contents of the picture layer and the adhesive layer. For example, urethane resin or other resin is used. The urethane resin here may be a thermoplastic urethane resin, but in terms of better adhesion and heat resistance, it is a curable urethane resin such as thermosetting (for example, a thermosetting two-component curable urethane resin). Is more preferred. For the thermosetting urethane resin, a thermosetting urethane resin using the blocked isocyanate described in the adhesive layer may be used, but it is usually necessary to consider handling such as preservation of a painting sheet in an uncured state. Since there is no isocyanate, an unblocked isocyanate can be sufficiently used. Further, the primer layer may be formed by a known printing method or coating method using an ink or coating liquid made of such a resin. Although the primer layer 4 is an easy-adhesion layer, it may be provided between other layers such as a base sheet and a picture layer as needed. In this case, the urethane resin or another resin is used depending on the intended layer material.

For example, as the two-part curable urethane resin, a urethane resin containing polyol as a main component and isocyanate as a crosslinking agent (curing agent) is used. The polyol has two or more hydroxyl groups in the molecule, and examples thereof include polyethylene glycol, polypropylene glycol, acrylic polyol, polyester polyol, polyether polyol, and polycarbonate polyol. As the isocyanate, a polyvalent isocyanate having two or more isocyanate groups in a molecule is used. For example, aromatic isocyanates such as 2,4-tolylene diisocyanate, xylene diisocyanate, 4,4'-diphenylmethane diisocyanate, or 1,6-hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, etc. Aliphatic (or alicyclic) isocyanate, or an adduct or multimer of the above-mentioned various isocyanates can also be used. For example, an adduct of tolylene diisocyanate, a trimer of tolylene diisocyanate (tr
imer) and the like. In addition, thermoplastic urethane resin,
It is composed of a linear polymer obtained by urethane-bonding a divalent polyol and a divalent isocyanate.

[Injection Simultaneous Painting Method] The simultaneous injection molding simultaneous painting method of the present invention uses the above-mentioned simultaneous injection molding simultaneous painting method of the present invention to laminate onto the surface of a resin molded product by a so-called injection molding simultaneous painting method. This is a method of obtaining a molded article painted with the painting sheet.

As described in JP-B-50-19132 and JP-B-43-27488, the painting sheet is placed between the male and female dies for injection molding. After that, a resin in a fluidized state is injected and filled into a mold, and a sheet for painting is laminated and painted on the surface of the molded resin at the same time as molding.

The simultaneous injection molding simultaneous painting method of the present invention takes various forms in the conventionally known injection molding simultaneous painting method, except that the above-described injection molding simultaneous painting sheet of the present invention is used as the painting sheet to be used. What you get. For example, the pre-forming of the painting sheet may or may not be performed. Further, the prepainting sheet may or may not be preheated. In addition, the sheet for painting is usually preheated at the time of preforming. In particular, in the present invention, in the case of preforming by heat-softening the painting sheet, the dissociation temperature of the blocking agent of the blocked isocyanate of the adhesive layer is set higher than the preheating temperature of the preforming as described above,
Depending on the choice of lowering, it is also possible to start thermosetting at the time of preforming, or not to start thermosetting at the time of preforming, to start thermosetting at the time of injection molding or after removing the molded article from the mold, Both are possible. However,
More preferred is the latter. In the latter case, even if the painting sheet is heated to a temperature sufficient for preforming by vacuum forming or the like, the curing reaction proceeds because the isocyanate of the adhesive layer is still blocked by the blocking agent. Without
The adhesive strength does not decrease before the injection resin and the adhesive layer come into contact with each other. Therefore, a stronger adhesive force can be stably obtained.

Of course, when the drawing sheet has a large drawing, it is preferable to carry out preforming. On the other hand, when the drawing sheet has a small aperture, the drawing sheet can be formed by the resin pressure of the resin in the flowing state to be injected. At this time, if the drawing is small, the painting sheet may be formed only by the resin pressure of the resin in the flowing state filled in the mold at the same time as the resin injection without the preliminary molding. Further, even when the painting sheet is formed by the resin pressure, the painting sheet may utilize the heat of the injection resin without preheating. In addition, in the preforming of the sheet for painting, usually, the mold for simultaneous painting with injection molding is also used as a vacuum forming mold, but before the sheet for painting is supplied between the molds, the painting is performed with another vacuum forming mold outside the mold. Preforming such as vacuum forming of a sheet for use may be used. In addition, the vacuum forming includes vacuum pressure forming.

The injection molding simultaneous painting method of the present invention will be described for each step as an example of a form in which an injection mold is also used as a vacuum mold and a painting sheet is preformed. There is an injection molding simultaneous painting method including the following steps. That is, a sheet supplying step of supplying a painting sheet on a female parting surface when a pair of male and female molds is in an open state, and a clamping step of holding and fixing the painting sheet on the female parting surface. A stretching step (preliminary molding step) of stretching the painting sheet along the cavity surface of the female mold, a mold clamping step of clamping the female mold and the male mold, and forming the female mold and the male mold. Injecting and filling the resin in the flow state into the cavity to be filled, an injection step of bringing the resin molded article into contact with the painting sheet, and a mold opening step of separating the female mold and the male mold after the injected resin is solidified, This is a simultaneous injection molding and painting method in which a molded product taking out step of taking out a molded product in which a painting sheet is laminated on a resin molded product is performed in this order.

FIG. 2 is a conceptual diagram illustrating the simultaneous injection molding and painting method of the present invention in one form. In the embodiment shown in FIG. 2, before the mold is clamped, the painting sheet is heated and softened between the molds, pre-molded by vacuum molding with an injection mold, and then the mold is clamped to inject the resin. Next, the injection molding simultaneous painting method of the present invention will be described with reference to FIG.

First, as shown in FIG. 2A, as an injection mold, a mold Ma having a runner (runner) and a gate (gate) communicating with the injection nozzle, and a sheet having a suction hole 41 on the mold surface. And a pair of molds of the mold Mb also serving as the preliminary mold. These molds are made of metal such as iron or ceramics. In the mold opened state, the sheet S for simultaneous painting with injection molding is supplied between the two molds Ma and Mb, and the sheet S for painting is fixed to the mold Mb by pressing with a frame-shaped sheet clamp 42 or the like. At this time, it goes without saying that the adhesive layer side of the painting sheet is the injection resin side on the right side of the drawing. Next, the painting sheet is appropriately heated and softened by a heater (not shown) inserted between both molds. The heating is, for example, non-contact radiation heating, but may be contact heating. Then, it is sucked through the suction hole and vacuum formed, and the painting sheet is preformed along the cavity surface of the mold Mb. In addition, vacuum forming may be vacuum press forming using both pressure and air, and this is also included. Next, the heater is retracted from between the two dies, the two dies are clamped as shown in FIG. 2B, and a cavity formed by the two dies is filled with a resin in a flowing state such as a heated and molten state. After the resin is solidified by cooling or the like, the mold is opened and the molded product is taken out. If there is an unnecessary portion of the painting sheet, trimming is appropriately performed. Then, as shown in FIG. 3, a sheet S for simultaneous painting with injection molding is laminated on the resin molded product 5 to obtain a painted product P.

At the stage immediately after the simultaneous painting by injection molding,
The thermosetting urethane resin of the adhesive layer whose thermosetting has not been completed is heated in an oven or the like to complete the curing to obtain the final adhesive strength. As described above, in this aspect, even if the adhesive layer of the injection-molding simultaneous painting sheet is a thermosetting urethane resin, heating the painting sheet, that is, preforming for heating and softening the painting sheet, or It is possible to prevent the curing reaction from proceeding to such an extent that the adhesive force is lost by the heat of the injection resin. Therefore, after the simultaneous painting by injection molding, the uncured adhesive layer is heated to complete the curing.

(Injection resin) In the simultaneous painting method for injection molding of the present invention, the resin to be injection-molded is not particularly limited, and may be a known resin. What is necessary is just to select according to the required physical properties of a product, cost, etc. For example, in the case of a thermoplastic resin, ABS (acrylonitrile-butadiene-styrene copolymer) resin, styrene resin, acrylic resin, vinyl chloride resin, polycarbonate resin, or polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene copolymer Polyolefin resins such as polymers, ethylene-propylene-butene copolymers, and olefin-based thermoplastic elastomers. In the case of a curable resin, a two-component curable resin, for example,
Uncured resin liquids such as urethane resins, unsaturated polyester resins, and epoxy resins. The thermoplastic resin is melted by heating and injected in a fluid state, and the curable resin (the uncured product) is injected in a flowing state at room temperature or appropriately heated. However,
The simultaneous injection molding painting method of the present invention is a method using the above-described simultaneous injection molding painting sheet of the present invention, and the characteristics of the painting sheet of the present invention can be exploited by polypropylene or the like which is usually difficult to adhere to. And the above-mentioned various polyolefin-based resins.

[Molded Article] The molded article of the present invention is shown in FIG.
Like the molded article P illustrated in (B), the sheet S for simultaneous painting with injection molding of the present invention described above is a molded article having a configuration in which the sheet S is laminated on the surface of a resin molded article 5 made of a polyolefin resin. FIG. 3A shows a molded article using the sheet for simultaneous painting with injection molding having the configuration shown in FIG. 1A, and FIG. 3B shows a molded article having the primer layer 4 as well. This is a molded article using the sheet for simultaneous painting with injection molding having the above configuration. Of course, in the molded product, the thermosetting urethane resin of the adhesive layer is a cured product. The polyolefin resin is, for example, one or a mixture of two or more of polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, and olefin-based thermoplastic elastomer. And so on. of course,
If necessary, a resin other than the polyolefin-based resin may be mixed as an auxiliary component. The molded article of the present invention is excellent in the heat resistance of the adhesion of the sheet for painting and, in addition, a base sheet mainly composed of an acrylic resin having excellent transparency can provide an excellent coating feeling. The molded product is usually a three-dimensional object in which the laminated surface of the sheet for painting is non-planar with an uneven surface or the like. However, the molded article of the present invention does not exclude a three-dimensional object in which the lamination surface of the painting sheet is flat but the other surface is non-planar, and a plate-like object in which the lamination surface is flat.

In order to obtain the molded article of the present invention, it is essential to use the sheet for simultaneous painting with injection molding of the present invention for the sheet for painting, and the sheet for simultaneous painting with injection molding is used as a resin molded article. As the lamination method, the above-described simultaneous injection molding painting method is suitable. However, the method for obtaining the molded article of the present invention is not necessarily limited to the injection molding simultaneous painting method. The irregular use of the sheet for simultaneous painting with injection molding will be an irregular use, but depending on the resin molding (the shape of the surface of the sheet for painting on which the surface is to be adhered) and the available manufacturing equipment, etc. May be adopted. For example, a so-called vacuum forming and laminating method described in JP-B-56-45768 (overlay method) and JP-B-60-58014 (vacuum pressing method) may be used. Of course, the simultaneous injection molding and painting method of the present invention is preferred in that molding and painting can be performed simultaneously in one step and the production efficiency is good.

[0034]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples.

[Embodiment] A sheet S for simultaneous painting with injection molding having a structure as shown in FIG. 1B is used as a base sheet 1 made of a transparent acrylic resin sheet having a thickness of 125 μm. A picture layer 2 (including all solid layers), a primer layer 4 having a thickness of 1 μm, and an adhesive layer 4 having a thickness of 4 μm were formed by gravure printing in this order. In the pattern layer, the binder resin is an acrylic resin and vinyl chloride.
The mixture was a 1: 1 weight ratio mixture with a vinyl acetate copolymer, and a coloring ink containing a red iron oxide, carbon black, and graphite was used as a coloring agent. For the primer layer, a two-component curable urethane resin primer ink composed of acrylic polyol and hexamethylene diisocyanate was used. And
The adhesive layer is made of a block isocyanate having a dissociation temperature of 105 ° C. and an acrylic polyol.
An adhesive ink composed of a liquid-curable thermosetting urethane resin was used.

Then, by the simultaneous injection molding simultaneous painting method of the present invention as shown in the conceptual diagram of FIG. 2, the above-mentioned sheet for simultaneous injection molding and painting is laminated on the surface of the resin molded article at the same time as the molding of the resin molded article. As shown in B), a molded article P of the present invention having a configuration in which the sheet S for simultaneous painting with injection molding was laminated on the resin molded article 5 was obtained. In the injection molding simultaneous painting method, the painting sheet was formed into a vacuum molding die as an injection molding die, supplied between the dies, heated and softened, and preformed by vacuum molding. As the injection molding die, a die having a suction hole for preforming the sheet on the female die side, which is a die from which a resin molded product to be a box-shaped panel was obtained was used. The heating temperature at the time of preforming the painting sheet was 100 ° C. In addition, a polypropylene resin was used as the injection resin.

Further, as a heat resistance test, the obtained molded article was placed in an oven at 100 ° C. for 60 hours (also for the purpose of completing the thermosetting of the adhesive layer), and then taken out and heated for 5 minutes or less. When a cross-cut cellophane adhesive tape adhesion test was performed, no peeling of the painting sheet was observed at all, and the heat resistance of adhesion of the molding sheet to the resin molded product was good. Further, the molded article was painted with a wood grain pattern and became a painted molded article having an excellent design feeling.

The cross-cut cellophane adhesive tape adhesion test described above shows that the molded product surface (painted sheet surface) has a thickness of 2 mm.
Cut notches vertically and horizontally at intervals to reach the depth of the resin molded product, and a total of 100
After making the individual cells, a cellophane adhesive tape (Nichiban Co., Ltd., "Cellotape" (registered trademark) 24 mm width, industrial use) was applied to the surface of the molded product while the molded product was still hot, and then the force was applied. It was peeled off well and evaluated by whether the painting sheet was peeled off together with the tape. Those without peeling were evaluated as good, and those with peeling were evaluated as poor.

[Comparative Example] In the examples, the adhesive made of the thermosetting urethane resin used for the adhesive layer was used as a resin component and chlorinated polypropylene (chlorine content: 22% by weight,
Except that the adhesive layer was formed by roll coating in place of the adhesive containing 18.5% by weight (average molecular weight: 45,000).
A sheet for simultaneous painting with injection molding was obtained in the same manner as in the example.
Then, using the sheet for painting, painting was performed simultaneously with injection molding in the same manner as in the example to obtain a molded product. Then, the obtained molded article was subjected to a heat resistance test in the same manner as in the examples. However, in the adhesive layer using chlorinated polypropylene, the heat resistance of the adhesion was insufficient, and the painting sheet was partially peeled off in the cross-cut cellophane adhesive tape adhesion test, resulting in a failure.

[0040]

According to the sheet for simultaneous painting with injection molding of the present invention, an acrylic resin having excellent transparency is used as a base sheet even for a resin molded product such as a polyolefin resin which is inexpensive but difficult to adhere to. A sheet for painting can be laminated on a resin molded product with good adhesion and heat resistance. In addition, although the urethane resin of the adhesive is a thermosetting type, it uses a blocked isocyanate, so the adhesive layer hardens too much during handling such as preservation of a painting sheet before painting at the same time as injection molding, and the adhesive strength is too high. There is no loss. In addition, in the simultaneous painting by injection molding, even when the painting sheet is heat-softened and preformed by heat, the heat at the time of heating and softening may cause the adhesive layer to be excessively hardened and lose adhesive strength. Hateful. In addition, by forming the base sheet, the pattern layer, and the adhesive layer from a specific resin, the coated sheet can have good adhesion between layers and can obtain an excellent coating feeling. In the simultaneous injection molding painting method of the present invention, by using the above-mentioned simultaneous injection molding painting sheet, the painting sheet can be molded with good heat resistance of adhesion even to a resin molded product such as a polyolefin resin which is inexpensive but difficult to adhere to. At the same time, they can be laminated and integrated. ADVANTAGE OF THE INVENTION According to the molded article of this invention, the adhesion of the sheet for painting and the heat resistance thereof are both good with the surface of the resin molding of a polyolefin resin which is inexpensive but hard to adhere, and the painting molding excellent in the feeling of painting. Goods.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a form example of a sheet for simultaneous painting with injection molding of the present invention.

FIG. 2 is a conceptual diagram illustrating an injection molding simultaneous painting method of the present invention in one embodiment.

FIG. 3 is a cross-sectional view illustrating an example of a form of a molded article of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base sheet 2 Picture layer 3 Adhesive layer 4 Primer layer 5 Resin molding 41 Suction hole 42 Sheet clamp Ma Injection molding die (male type) Mb Injection molding die (female type) P molded product S Injection molded simultaneous painting sheet

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4F100 AK03D AK15B AK22B AK25A AK25B AK51C AL01B AL05B BA03 BA04 BA10A BA10C BA10D BA15 CA13B CB00C GB90 HB01B JB13C JL11 JN01A 4F206 AA03 AD03 J0513 CC02 CD01 CD05 FA01 FA10

Claims (3)

[Claims] 1. A painting sheet used for simultaneous painting by injection molding, wherein a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer is used as a binder resin on a transparent base sheet mainly composed of an acrylic resin. A sheet for simultaneous painting with injection molding, comprising, in this order, a picture layer to which a coloring agent is added as a main component and an adhesive layer mainly containing a thermosetting urethane resin using a blocked isocyanate. 2. After the sheet for simultaneous painting with injection molding according to claim 1 is inserted between a pair of molds so that the adhesive layer side faces the resin to be filled, both molds are clamped. After filling the resin in the fluid state into the cavity formed by both molds and solidifying it, and attaching and laminating the sheet for simultaneous injection molding and painting on the surface of the resin molded product at the same time as molding, open both molds, An injection molding simultaneous painting method for obtaining a molded product in which an injection molding simultaneous painting sheet is laminated on a resin molded product. 3. A molded article obtained by laminating the sheet for simultaneous painting with injection molding according to claim 1 on a surface of a resin molded article made of a polyolefin resin by its adhesive layer.