JP2000102949A - Production of coated molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To coat the surface of a molding, even when the surface is complex in shape, with a surface coating layer of a rigid membrane of a uniform thickness. SOLUTION: When a coated molding in which a resin molding is coated with a surface coating layer by using a simultaneous injection molding/painting method in which a decorative sheet S having the surface coating layer 1 is inserted between molds of a pair, the molds are clamped, a cavity is filled with a resin, and the sheet S is adhered to the resin molding simultaneously with molding, the surface coating layer of the sheet S is formed from the layer of an uncured thermosetting resin which is solid at room temperature, the heat- curing of the surface coating layer is advanced by heat obtained during the simultaneous injection molding/painting, and the surface coating layer of the coated molding is cured. Heat in the softening of the decorative sheet and others are used for the simultaneous injection molding/painting. The progress of the heat curing can be done in a heating process after molding after the simultaneous injection molding/painting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a painted product. In particular, the present invention relates to a method for producing a coated molded product in which a surface coating layer made of a hard coating having scratch prevention and antifogging properties is provided on the surface of the molded product where the decorative sheet is deeply drawn.

[0002]

2. Description of the Related Art Conventionally, for example, the following method has been used to provide a surface coating layer made of a hard coating on the surface of a resin molded product. After painting the resin molded product by the simultaneous painting method of injection molding, vacuum forming lamination method, hydraulic transfer method, etc., apply a clear coating of a curable resin that cures with ultraviolet light, heat, etc., and cure by applying ultraviolet light, heat, etc. To form a surface coating layer comprising a cured product of a curable resin. JP-B-59-23248, JP-B-59-455
No. 02, Japanese Patent Publication No. 1-47284, etc., using a decorative sheet in which a surface coating layer made of a cured product obtained by curing a curable resin by ultraviolet rays, electron beams, or heat in advance, A method in which the decorative sheet is laminated on the surface of the resin molded product by the simultaneous painting method of injection molding to apply a surface coating layer made of a cured product of a curable resin to the resin molded product. Alternatively, as disclosed in Japanese Patent Publication No. 5-43507, a surface coating layer made of an uncured material of a curable resin that is solid at room temperature and thermoplastic at room temperature in an uncured state and is cured by ultraviolet rays or electron beams is formed. Using a decorative sheet formed on a possible base sheet, the decorative sheet is laminated on the surface of the resin molded product by an injection molding simultaneous painting method, and then cured by irradiating ultraviolet rays or the like, and the curability is improved. A method of forming a surface coating layer made of a cured resin.

[0003]

However, according to the above-mentioned method, the manufacturing process involves two steps: a painting step and a post-coating step. The part was thin and the concave part was thick and non-uniform. In addition, since there is a coating process, additional equipment such as solvent recovery is required. Further, in the above method, since the surface coating layer is a cured product layer in which the resin has already been cured at the stage of the decorative sheet, it cannot be applied to a molded product having a shape in which the decorative sheet is deeply drawn. When the decorative sheet was forcibly formed, the surface coating layer could not follow and cracked. Further, in the above method, the surface coating layer is cured by using ultraviolet rays or the like after the simultaneous painting with the injection molding, so that the disadvantage of the above method does not occur. However, if the shape of the molded article is complicated, FIG. Intermediate molded product W
As conceptually illustrated in the above, there is a possibility that a portion of the shadow 7 where the ultraviolet rays R are not sufficiently applied may occur. Therefore, the surface coating layer is not completely cured at the shadow 7 and uneven curing occurs.
In order to prevent such curing unevenness, it is necessary to sequentially irradiate from a plurality of different directions or to install an irradiator having a plurality of different irradiance directions and simultaneously irradiate from multiple directions. However, it becomes complicated and expensive, and the irradiation step becomes long. Further, every time the shape of the intermediate molded product W changes, it is necessary to change the setting of the irradiation device. The same applies to the case of curing with an electron beam.

[0004] Therefore, an object of the present invention is to use an injection molding simultaneous painting method using a decorative sheet to uniformly cure the surface of a molded product in which the drawing of the decorative sheet is deep without causing cracks. An object of the present invention is to provide a method for producing a coated molded article, which can produce a coated molded article provided with a surface coating layer of a hard coating made of a cured product by a simple apparatus and process.

[0005]

In order to solve the above-mentioned problems, a method for producing a coated molded article according to the present invention comprises inserting a decorative sheet having a surface coating layer between a pair of dies, After filling the fluidized resin into the cavity formed by both molds and solidifying it, the decorative sheet is brought into close contact with the surface of the resin molded product and laminated at the same time as molding, and then both molds are opened. In the method for producing a coated molded article in which a resin molded article is coated with a surface coating layer made of a cured product of a curable resin using a simultaneous painting method for injection molding, The surface coating layer is made of an uncured thermosetting resin and is a layer of a solid at room temperature, and the heat curing of the surface coating layer is advanced by heat during simultaneous painting with injection molding to form the surface coating layer in the coated molded article. It was made to be a cured product. As a result, the thermosetting resin of the surface coating layer has thermoplasticity because it is in an uncured state at the stage of the decorative sheet, and the decorative sheet is formed without cracking of the surface coating layer even in the case of a deeply drawn molded product surface shape. Thus, a coated molded product in which the surface of the resin molded product is covered with the surface coating layer can be manufactured. Moreover, since the resin of the surface coating layer is cured by heat, the thermosetting reaction can be advanced by utilizing the heat at the time of simultaneous painting with injection molding. In addition, even in the case of a complicated shape, the surface coating layer can be formed as a layer in a non-fluid state, so that the thickness unevenness of the coating film which occurs in a post-coating method applied in a flow state does not occur, and the concave portion of the molded product is not formed. And the projections also have a uniform thickness. In addition, molding and coating (formation of a surface coating layer) are completed in one step. Further, even in the case of a complicated shape, curing unevenness due to the shadow of the radiation generated by curing by ultraviolet irradiation or the like does not occur.

[0006] The method for producing a coated molded article of the present invention comprises:
In the above method, after inserting the decorative sheet between a pair of molds, before clamping both molds, when vacuum-molding the decorative sheet with the mold as a vacuum mold, the surface coating layer Using a decorative sheet in which the thermosetting reaction of the constituent thermosetting resin is started at a temperature lower than the temperature at which the decorative sheet is heated during vacuum forming, the heat curing of the surface coating layer is advanced by the heat during vacuum forming. The surface coating layer of the coated molded article is made a cured product. According to this method, even a molded product having a deeper drawn shape can be applied by vacuum forming, and the thermosetting reaction of the surface coating layer can be advanced by utilizing heat at the time of vacuum forming. Of course, in this embodiment, the heat of the injection resin may be used for the progress of the thermosetting reaction.

[0007] The method for producing a coated molded article of the present invention comprises:
In each of the above methods, further heat curing of the surface coating layer,
The intermediate molded product coated with the resin molding with the surface coating layer is heated after being advanced halfway by the heat during simultaneous injection molding painting, and then removed from the mold by simultaneous injection molding painting, after molding. By further proceeding through the heating step, the surface coating layer in the coated molded article was made into a cured product. In this method, the heating and curing of the surface coating layer are performed both during the simultaneous painting by injection molding and during the heating step after molding. It is possible to suppress the progress of the heat curing of the surface coating layer so as not to cause cracks in the surface coating layer. In addition, the heating step after molding can be easily performed, for example, by simply placing the intermediate molded article after injection molding in a high-temperature atmosphere.

[0008] The method for producing a coated molded article of the present invention comprises:
After inserting the decorative sheet having the surface coating layer between the pair of molds, the molds are clamped, and the cavity formed by the molds is filled with a resin in a flowing state and solidified, and the molding is performed. At the same time, after the decorative sheet is adhered and laminated on the surface of the resin molded product,
In the method for producing a coated molded article, in which a resin molded article is coated with a surface coating layer made of a cured product of a curable resin by using an injection molding simultaneous painting method of opening both molds, Heat-curing of the layer is removed from the mold by simultaneous painting with injection molding, heated to an intermediate molded product coated with a resin molded product with an uncured surface coating layer, and advanced by a post-molding heating step to coat. The surface coating layer in the molded article was made to be a cured product. In this method, the thermosetting resin of the surface coating layer is in an uncured state at the stage of the decorative sheet and therefore has thermoplasticity, similarly to the above-mentioned respective manufacturing methods, and the surface coating layer has cracks even in the case of a deeply drawn molded product. The decorative molded sheet can be molded without using the resin, and a coated molded product in which the surface of the resin molded product is covered with a surface coating layer can be manufactured. Moreover, the heating and curing of the surface coating layer can be easily performed as a heating step after molding, for example, by simply placing an intermediate molded article after injection molding in a high-temperature atmosphere. In this embodiment, the heat at the time of simultaneous painting by injection molding may be used as described above, but the heat at the time of simultaneous painting by injection molding may not be used. It is not essential to advance heat curing at the time of simultaneous painting with injection molding.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for producing a coated molded product of the present invention will be described with reference to the drawings. 1 is a cross-sectional view illustrating a decorative sheet that can be used in the present invention, FIG. 2 is a cross-sectional view illustrating a coated molded article obtained in the present invention, and FIG. 3 is a method for manufacturing a coated molded article in the present invention. FIG. 4 is a conceptual view conceptually illustrating an injection molding simultaneous painting method to be employed in one form of the method. FIG. 4 is a cross-sectional view conceptually illustrating a shadow which causes uneven curing in the case of curing with ultraviolet rays as a conventional method. FIG.

[Decorative Sheet] First, the decorative sheet used in the present invention may be a transfer type sheet in addition to a laminate type sheet. In the case of the laminate type,
The outermost layer of the decorative sheet is the surface coating layer, and after all the layers of the decorative sheet are laminated on the resin molded product, the molded product in which the decorative sheet is permanently integrated with the resin molded product Used. In the case of a transfer type decorative sheet, there is a base sheet which can be released from the surface coating layer on the outermost surface layer of the decorative sheet, and the surface coating layer is temporarily provided on (the back side of) the base sheet. The structure is bonded. After laminating the decorative sheet on the resin molded product, only the base sheet of the decorative sheet is peeled off to obtain a molded product in which only the transfer layer including at least the surface coating layer is laminated on the resin molded product.

First, FIG. 1 is a cross-sectional view illustrating a decorative sheet that can be used in the present invention, and FIG. 1A is a cross-sectional view illustrating an example of a laminate type decorative sheet S. B)
FIG. 4 is a cross-sectional view illustrating an example of a transfer type decorative sheet S. In the decorative sheet S of FIG. 1A, the surface coating layer 1 is formed on the front side of the base sheet 2 and the base sheet 2
Is a sheet on which a decorative layer 3 and an adhesive layer 4 are formed in this order on the surface on the back side of the sheet. On the other hand, the transfer type decorative sheet S shown in FIG. 1B is a sheet having the surface coating layer 1 as the transfer layer 5 on the release base sheet 2a. 2a, in order from the surface coating layer 1,
It has a decorative layer 3 and an adhesive layer 4. In these decorative sheets, the surface coating layer 1 is formed of an uncured thermosetting resin and a solid layer at room temperature. In these decorative sheets, the decorative layer and the adhesive layer can be omitted, but usually have a decorative layer. The decorative sheet of the laminate type comprises at least the surface coating layer 1, but usually has the surface coating layer 1 and the base material sheet 2, or the decoration layer 3 and the like. In the case of the transfer-type decorative sheet, at least the base material sheet 2 a having releasability and the surface coating layer 1 as the transfer layer 5.
Consists of

(Surface Coating Layer) The surface coating layer 1 is a room-temperature solid layer made of an uncured thermosetting resin at the stage of a decorative sheet. Therefore, the surface coating layer is thermoplastic at the stage of the decorative sheet. Then, the thermosetting reaction of the thermosetting resin is advanced by one or more of heat such as heat at the time of vacuum molding using the injection mold, heat of the injection resin, or heat in the post-molding heating step, Finally, the surface coating layer covering the resin molded product in the coated molded product is a cured product. In the coated molded article, the surface coating layer is used for improving surface properties such as scratch prevention, chemical resistance, and anti-fogging property, or for imparting a design feeling such as painting feeling. In addition, it is preferable that the above-mentioned thermosetting does not proceed as much as possible at room temperature in consideration of the storage of the decorative sheet and the like. Therefore, the thermosetting reaction start temperature uses heat at the time of vacuum forming of the decorative sheet. When the curing reaction is allowed to proceed, the temperature is usually about 100 to 200 ° C. However, in the case where the resin molded product is heated to the intermediate molded product coated with the surface coating layer in the post-molding heating process after the simultaneous painting of the injection molding and the thermosetting proceeds, the curing reaction start temperature is already set. At a temperature higher than the heat resistant temperature (thermal deformation temperature) of the molded injection resin,
Since the molded article is deformed by heat, the temperature is preferably lower than the heat-resistant temperature so as not to be deformed. When the decorative sheet on the molded article includes the base sheet, the temperature is preferably lower than the heat-resistant temperature of the base sheet.

As such a thermosetting resin which can be a surface coating layer, a thermosetting resin consisting of an uncured material at room temperature and having a curing start temperature corresponding to a temperature at which the thermosetting proceeds. Any resin may be used as long as it is a conductive resin, and there is no particular limitation. For example, a thermosetting resin composed of a reactive acrylic resin that is solid at room temperature and a blocked isocyanate may be used.

The reactive acrylic resin is an acrylic resin having in its molecule a functional group which reacts with floc isocyanate. The functional group is, for example, a hydroxyl group, an amino group,
An active hydrogen-containing functional group such as a carboxyl group. The reactive acrylic resin is an acrylic polymer that has a plurality of one or more of these functional groups and is solid at room temperature. For example, it is an acrylic prepolymer having a plurality of hydroxyl groups, amino groups and / or carboxyl groups. Such a reactive acrylic resin includes, for example, a (meth) acrylate monomer, a styrene derivative monomer, a (meth) acrylate monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, and 2-amino. It is obtained by copolymerizing a monomer having an amino group such as ethyl (meth) acrylate and / or a monomer having a carboxyl group such as (meth) acrylic acid. The reactive acrylic resin having at least a plurality of hydroxyl groups is also an acrylic polyol. In addition, (meth) acrylate means acrylate or methacrylate, and (meth) acrylic acid means acrylic acid or methacrylic acid. In the present invention, "normal temperature" means that the decorative sheet is stored,
It means the indoor (or outdoor) ambient temperature inserted between the molds. The specific value varies depending on the climate and working environment, but is usually in the range of 10 to 40 ° C. The reactive acrylic resin is, for example, a mixture of reactive acrylic resins having different active hydrogen-containing functional groups, a mixture of reactive acrylic resins having different weight average molecular weights, or a combination of different reactive acrylic resins. May be used.

The weight-average molecular weight (Mw) of the reactive acrylic resin is, for example, 100,000 to 1,
A range of 1,000,000 is preferred. Weight average molecular weight is 1
If it is less than 000, it becomes difficult to maintain the shape as a sheet when a decorative sheet comprising only the surface coating layer is formed. On the other hand, if the weight average molecular weight exceeds 1,000,000, the moldability is reduced, and cracks are likely to occur in the surface coating layer as an uncured material during the formation of the decorative sheet. The reactive acrylic resin is preferably a resin having a glass transition temperature of 0 to 80 ° C. and a functional group value such as a hydroxyl value of 20 to 200. As a result, favorable physical properties such as blocking resistance during storage of the decorative sheet, moldability of the surface coating layer with the uncured material at the time of molding, and surface physical properties of the surface coating layer with the obtained cured product are obtained.

The above-mentioned block isocyanate is used as a heat-reactive curing agent which reacts with an active hydrogen-containing functional group such as a hydroxyl group of a reactive acrylic resin by heating. The block isocyanate to be used means a compound obtained by blocking an isocyanate group of an isocyanate compound having two or more isocyanate groups in a molecule with a blocking agent such as phenol, oxime, ε-caprolactam, and malonic ester. As the isocyanate compound, for example, monomers such as tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate,
Alternatively, there are trimethylolpropane adducts, isocyanurate modified products, carbodiimide modified products and the like.
The block isocyanate is released from the block isocyanate by heating, and the generated isocyanate group reacts with a functional group (hydroxyl group, amino group, carboxyl group, etc.) of the reactive acrylic resin. The reaction is usually a cross-linking curing reaction, and the cross-linking curing reaction is also preferable in terms of the physical properties of the cured product.

Here, the functional group value is the total of hydroxyl value, amino value, acid value and the like. The amino group value is a value calculated by calculating the amount of the amino group added at the time of polymerization in the same manner as the hydroxyl group value, or by quantifying the amount by reacting the amino group with nitrous acid to convert it to a hydroxyl group. The acid value is a value obtained by calculating the amount of the carboxyl group added during the polymerization in the same manner as the amount of the hydroxyl group, or quantifying the carboxyl group with KOH or the like. The ratio of the reactive acrylic resin to the block isocyanate is such that the ratio of the functional group contained in the reactive acrylic resin to the isocyanate group contained in the block isocyanate is usually 0.5 to 0.5.
2.0, more preferably in the range of 0.8 to 1.2.

Incidentally, as the reactive acrylic resin, a reactive acrylic oligomer having a weight average molecular weight in the range of 1,000 to 10,000 may be used in combination. The reactive acrylic oligomer has a weight average molecular weight of 100,000 to 1,0.
Only the weight average molecular weight is different from the above-mentioned reactive acrylic resin of 000, and the functional groups are a hydroxyl group, an amino group, a carboxyl group and the like. For example, a (meth) acrylate monomer, a styrene derivative monomer,
(Meth) acrylate monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2
-An oligomer obtained by copolymerizing a (meth) acrylate monomer having an amino group such as aminoethyl (meth) acrylate and / or a monomer having a carboxyl group such as (meth) acrylic acid.
By using the reactive acrylic oligomer in combination, it is possible to adjust the moldability of the surface coating layer with the uncured product, the surface properties of the surface coating layer with the cured product, and the like. The value of the functional group when the reactive acrylic oligomer is used is, of course, the total of the reactive acrylic resin and the reactive acrylic oligomer.

For example, a surface coating layer composed of an uncured thermosetting resin as described above is coated on a base sheet described later using a coating liquid (or ink) containing the thermosetting resin ( Or printing). Alternatively, after forming a surface coating layer on a release-type base sheet as described in the transfer type decorative sheet, if only the surface coating layer is peeled off, a decorative sheet having only the surface coating layer can be obtained. it can. The coating method (or printing method) may be a conventionally known method. For example, the coating method includes gravure coating and roll coating, and the printing method includes gravure printing and silk screen printing. The thickness of the surface coating layer may be a thickness according to the application, for example, 1 to 100
It is about μm.

In the surface coating layer, if necessary, an ultraviolet absorber such as benzotriazole or ultrafine cerium oxide, a light stabilizer such as a hindered amine radical scavenger, a coloring pigment, an extender pigment, silica, a spherical A lubricant such as α-alumina or the like, a lubricant such as wax, an anti-fogging agent such as a surfactant or the like may be contained.

(Base Sheet) As the base sheets 2 and 2a, a resin sheet having thermoformability is typically used.
If the base sheet 2a has releasability from the transfer layer,
Base sheet 2 used for laminated type decorative sheet
But can be used. Further, a base sheet 2a having releasability.
In the case where the release property is insufficient with only the resin sheet, a configuration in which the release layer is provided on the base sheet 2 made of the resin sheet may be used. Examples of the resin sheet used for the base sheets 2 and 2a include polypropylene, polyethylene, polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, and olefin-based thermoplastic elastomer. Polyolefin resins, such as ethylene-isophthalate-terephthalate copolymer, polyester resin such as polybutylene terephthalate, polyamide resin such as nylon, vinyl chloride resin, acrylic resin, ABS resin (acrylonitrile-butadiene-styrene copolymer), A single layer of a sheet of a thermoplastic resin such as another thermoplastic elastomer such as urethane or a laminate of two or more layers of different materials is used. The thickness of the base sheet is not particularly limited, but is generally about 30 to 200 μm, and 20
About 100 μm.

In order to obtain a releasable base sheet, a base sheet having a structure in which a known release layer is provided on the transfer layer side of the resin sheet may be used. The release layer is a layer that is removed from the transfer layer integrally with the base sheet when the base sheet is peeled. In this release layer, for example, silicone resin,
Melamine resin, wax and the like are used.

Further, in the case of a base sheet used for a decorative sheet of a laminate type, a coloring agent, for example, listed with a printing ink described below, is kneaded into a resin sheet serving as the base sheet, so that the base sheet is colored and transparent. Alternatively, decoration processing such as colored opaque or colorless opaque may be performed.

[Decoration Layer] The decoration layer is a conventionally known layer formed by printing or the like as necessary. The decorative layer is formed at a position below the surface coating layer in the state of the coated molded article. In the case of a laminate type decorative sheet, the decorative sheet may be on the front side, the back side, or both sides of the base sheet. The decorative layer is usually formed by a known printing method such as gravure printing using a printing ink obtained by adding a coloring agent or the like to a binder. When the decorative layer has a solid pattern on the entire surface, a known coating method such as roll coating using a coating liquid may be used. As a binder resin for printing ink (or paint), acrylic resin, vinyl chloride-vinyl acetate copolymer, polyester resin, urethane resin, chlorinated polyolefin, etc.,
Alternatively, two or more kinds are used in combination. As the coloring agent, for example, inorganic pigments such as titanium white, carbon black, ultramarine, red iron oxide, and graphite, and organic pigments or dyes such as quinacridone, isoindolinone, phthalocyanine blue, and aniline black are used. When the decorative layer is a metal thin film layer, it is formed by a vacuum evaporation method of aluminum, chromium, or the like, a sputtering method, or the like. The metal thin film layer is an entire surface or a partial (pattern or the like) layer. The pattern of the decoration layer is wood grain, stone grain, cloth grain, sand grain, geometric pattern, character, solid color, and the like.

(Adhesive Layer) An adhesive layer is provided if necessary. If the back surface of the decorative sheet on the resin molded product side is insufficient in adhesiveness with the resin molded product, in order to improve the adhesiveness, a corona discharge treatment, or an easy adhesive treatment such as various known primer coatings, or This adhesive layer is applied appropriately. For the adhesive layer, a thermoplastic resin or a thermosetting resin is used. For example, in thermoplastic resin, polystyrene, poly α
Styrene resin or styrene copolymer such as methylstyrene, acrylic resin such as poly (methyl) acrylate, ethyl poly (meth) acrylate, butyl poly (meth) acrylate, olefin chlorinated polyolefin such as chlorinated polypropylene Resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer, vinyl polymer such as polyvinyl butyral, rubber resin such as polyisoprene rubber, polyisobutyl rubber, styrene butadiene rubber, butadiene acrylonitrile rubber, polyamide resin One or a mixture of two or more kinds of thermoplastic resins such as. In addition, in the thermosetting resin, other than phenol resin, urea resin, diallyl phthalate resin, melamine resin,
A thermosetting resin or the like used for the surface coating layer may be used.

[Injection Simultaneous Painting Method] In order to cover the surface of the resin molded product with the surface coating layer, the decorative sheet is laminated on the resin molded product by using the simultaneous injection molding painting method. The decorative sheet is laminated on the surface of the molded article simultaneously with the molding. And in the case of a transfer type decorative sheet, after that, only the base sheet of the decorative sheet is peeled off,
Only the transfer layer having the surface coating layer is left on the resin molded product.
The timing at which the heat curing of the surface coating layer proceeds will be described after the description of the simultaneous injection molding painting method.

The injection molding simultaneous painting method adopted here is as follows.
JP-B-50-19132, JP-B-43-274
As described in JP-A-88-88, etc., a so-called injection molding simultaneous painting laminating method in which a decorative sheet of a laminate type is used and a decorative sheet is permanently laminated on the surface of the resin molded article at the same time as molding. Method or JP-A-6-3159
As described in Japanese Patent Publication No. 50, Japanese Patent Publication No. 2-42080, etc., a transfer type decorative sheet is used, and at the same time as a resin molded product is formed, only a transfer layer is transferred from the decorative sheet to the surface by transfer. Or the so-called simultaneous injection molding and painting transfer method. Laminate and transfer are selected according to the intended use of the coated molded product, required specifications, and the like.

It should be noted that the simultaneous injection molding and painting method employed in the present invention may basically be either in a form in which the decorative sheet is preformed or not. Further, the decorative sheet may or may not be preheated. In addition,
Usually, the decorative sheet is preheated during preforming. Of course, when the decorative sheet has a large drawing, it is preferable to perform preforming. On the other hand, when the decorative sheet has a small drawing, the decorative sheet may be formed by the resin pressure of the resin in the flowing state to be injected. Further, even when the decorative sheet is formed by the resin pressure, the decorative sheet may utilize the heat of the injection resin without preheating. In addition, the preforming of the decorative sheet may be preforming such that the decorative sheet is vacuum-formed with another vacuum forming die outside the mold before supplying the decorative sheet between the molds, but wrinkles are easily formed. For this reason, preferably, the injection molding die is used also as the vacuum molding die. In addition, the vacuum forming includes vacuum pressure forming.

Next, the simultaneous injection molding painting method will be described with reference to the conceptual diagram of FIG. In addition, the form of the simultaneous injection molding painting method shown in the figure, after the decorative sheet is heated and softened between the molds before clamping, and preformed by vacuum molding using the injection mold as a vacuum mold, This is a form in which the resin is injected after clamping. In addition, this form is, among the various forms of the preforming and preheating of the decorative sheet described above,
This is a more preferable mode when the decorative sheet has a large aperture.

First, as shown in FIG. 3A, as an injection mold, a mold Ma having a runner and a gate (gate) communicating with an injection nozzle, and a suction hole 41 on a mold surface are used. A pair of molds of the mold Mb that also serves as a preform for the decorative sheet is used. These molds are made of metal such as iron or ceramics. Decorative sheet S on mold Mb with mold open
Is fixed by pressing or the like with a frame-shaped sheet clamp 42. At this time, in the case of the laminate type decorative sheet, the surface coating layer side is set to the mold surface side in contact with the decorative sheet, and in the transfer type decorative sheet, the base sheet side is set in contact with the decorative sheet. Needless to say, the surface side is used.

Next, as shown in FIG. 3 (B), the decorative sheet is heated and softened by inserting the heater 43 between the molds from the retracted position outside the mold. In the case of the drawing, the heating is an example of non-contact radiation heating, but may be contact heating. Then, as shown in FIG. 3 (C), the decorative sheet is vacuum-formed by suction through the suction hole, and
Preforming along the cavity surface of b. 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 molds, and FIG.
After the molds are clamped as in (D), the cavity formed by the molds is filled with a resin in a fluidized state such as a heated and melted state.
After the resin is solidified by cooling or the like, the mold is opened and the molded product W is taken out. In the case of the laminate type decorative sheet, the excess decorative sheet protruding outside the outer periphery of the molded product is trimmed (cut and removed), and in the case of the transfer type decorative sheet, only the base sheet is used. From the molded product to leave only the transfer layer.

The molded article W is the intended coated molded article if the curing reaction of the surface coating layer has already been completed at that stage. If the curing reaction has not been completed, it is an intermediate molded product. The intermediate molded article becomes a target coated molded article if the curing reaction is completed by a heating step after molding.

The molding resin to be injection molded is not particularly limited.
Conventionally known ones in the injection molding simultaneous painting method can be used. For example, if it is a thermoplastic resin, ABS (acrylonitrile-butadiene-styrene copolymer) resin,
AS (acrylonitrile-styrene copolymer) resin, styrene resin, vinyl chloride resin, acrylic resin, polycarbonate resin, or polyethylene, polypropylene,
Polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer,
There are polyolefin-based resins such as olefin-based thermoplastic elastomers, and if it is a curable resin, a two-part curable resin, for example, a urethane resin, an unsaturated polyester resin,
Conventionally known materials such as an uncured resin liquid such as an epoxy resin for painting by injection molding can be used. The thermoplastic resin is heated and melted, injected in a fluid state and solidified by cooling, and the curable resin is injected at room temperature or appropriately heated and fluidized to be solidified by a chemical reaction.

[Time when heat curing of the surface coating layer is advanced] The time when the thermosetting reaction of the thermosetting resin constituting the surface coating layer is advanced by heat can be roughly classified into simultaneous painting by injection molding and injection molding. There is a heating step after molding after simultaneous painting. In addition, the time when this heat curing proceeds is as follows.
It is only necessary that the heat curing reaction is progressing at that time,
It is not necessary to complete. However, in the heating step after molding, the thermosetting reaction is naturally completed.
In addition, the time when the heat curing reaction starts may be before the simultaneous injection molding and painting with the decorative sheet. This is the case where the reaction partially proceeds during storage. However, at the stage before simultaneous painting with injection molding, it is usually desirable that the film be completely uncured.

As the heat at the time of simultaneous painting by injection molding, first, the heat of the injection resin charged in a heated and molten state can be used, but the surface coating layer is in contact with the mold surface (Lamine -In the case of a decorative sheet of a type, or close (in the case of a decorative sheet of a transfer type), usually, the temperature tends to be closer to the heated mold temperature than to the temperature of the injection resin itself. If the curing reaction can proceed even at such a temperature, the heat of the injection resin or the heat of the heated mold can be used. However, the heat at the time of heating and softening the decorative sheet can be used as the higher temperature heat in order to improve the formability of the decorative sheet. The heating and softening of the decorative sheet is performed in order to form the decorative sheet directly by the resin pressure of the injection resin, although the decorative sheet is vacuum-formed or not vacuum-formed. However, in this case, before the decorative sheet is completely cured, the decorative sheet is formed (deformed) so that the curing reaction is excessively advanced by the heat of the preheating of the decorative sheet and the surface coating layer is hardened and cracks are not generated at the time of forming the decorative sheet. It is preferred that As the heat at the time of simultaneous painting with injection molding, both the heat of the injection resin and the heat at the time of preheating the decorative sheet may be used.

When the heat at the time of preheating of the decorative sheet is used for the progress of heat curing, the decorative sheet has a heating start temperature lower than the temperature at which the decorative sheet is preheated. Use a decorative sheet. This makes it possible to achieve both the heating temperature required for heating and softening the decorative sheet and the heating temperature required for the intended curing reaction to proceed. For this, a decorative sheet having physical properties such that the heating temperature is higher than the starting temperature of the thermosetting reaction may be selected and used.

On the other hand, in the case of the heating step after molding,
At a temperature at which the molded product does not deform in consideration of the heat resistance of the molded product,
Heating may be performed solely until the completion of the heat curing reaction of the surface coating layer. In the case where heating and curing are performed in the heating step after molding, the heating and curing may be performed halfway during the simultaneous painting with injection molding. In this case, in the post-molding heating step, the curing reaction of the remaining uncured portion proceeds to complete the curing reaction. Further, as described above, in order to prevent the occurrence of cracks in the surface coating layer during decorative sheet vacuum forming,
Without complete curing during vacuum molding, subsequent complete curing
The mode performed in the heating step after molding is a preferable mode.
Alternatively, when the decorative sheet is not heated and softened, or when the temperature is lower than the temperature required for the curing reaction even after the heating and softening, the temperature of the injection resin is set to room temperature or a two-part curable resin liquid or the like which is appropriately heated. In the case where the temperature is lower than the temperature required for the curing reaction, heat at the time of simultaneous painting with injection molding may not be used. In such a case, the curing reaction of the surface coating layer may proceed in a heating step after molding.

[Coated molded article] Here, FIG. 2 shows an example of a coated molded article obtained by the present invention in a sectional view. The coated molded article P shown in the figure is a coated molded article having a configuration in which the decorative sheet S is laminated on the surface of the resin molded article 6 to cover the resin molded article 6 with the surface coating layer 1. The surface coating layer 1, the base sheet 2, the decorative layer 3, and the adhesive layer 4 serve as a decorative sheet S in order from the surface side of the coated molded article, and the resin molded article 6.
It is the structure laminated | stacked.

[Use of coated molded article] The use of the coated molded article obtained by the present invention is not particularly limited, and can be used for various uses. For example, interior building materials such as walls, ceilings, floors, etc., window frames, doors, handrails, sills, surface decoration materials such as fittings such as lintels, furniture such as chests of drawers, and weak electric / OA equipment such as television receivers. Surface cosmetic materials for cabinets, interior materials for vehicles such as automobiles and trains, aircraft, ships, etc., or various packaging containers and materials such as bottles, cosmetic containers, and accessories, miscellaneous goods such as premiums and accessories And other various uses.

[0040]

The present invention will be described in more detail with reference to the following examples.

Example An acrylic resin sheet having a thickness of 125 μm and containing polymethyl methacrylate as a main component was prepared as a base sheet. Then, on one surface of the base sheet, a decorative layer having a wood grain pattern was formed by gravure printing in three colors. The ink used for the decorative layer is a vehicle using a mixed resin of a vinyl chloride-vinyl acetate copolymer and an acrylic resin in a ratio of 1: 1 by weight as a binder resin, a red stalk, carbon black, isoindolinone and titanium. A coloring ink obtained by adding a white coloring pigment was used.
Further, a 10 μm-thick adhesive layer made of a vinyl chloride-vinyl acetate copolymer was formed on the decorative layer by roll coating. Further, 100 parts by weight of a normal temperature solid acryl polyol (weight average molecular weight: 340,000, glass transition temperature: 40 ° C., hydroxyl value: 80) as a reactive acrylic resin was formed on the surface of the base sheet opposite to the surface on which the adhesive layer was formed. Block isocyanate (oxime block of hydrogenated diphenylmethane diisocyanate, isocyanate group% 7.
3) 49 parts by weight (the isocyanate group and the hydroxyl group are 1.0
Of thermosetting two-component curable urethane resin, which is a solid at room temperature and has a thermoplastic thickness of 15 μm.
m was formed by roll coating to obtain a decorative sheet.

Then, the decorative sheet is inserted between the male and female molds in the mold opened state, and is fixed to the female parting surface by a sheet clamp. Then, a ceramic heater heated to a surface temperature of 350 ° C. After heating the decorative sheet to 130 ° C. by non-contact heating, vacuum forming was performed by vacuum suction through a female mold suction hole. At this time, when the decorative sheet was heated and softened, the surface coating layer was also heated and cured (however, it did not reach complete curing). Next, the heater was returned to the retracted position outside the mold while the vacuum-formed decorative sheet was along the cavity surface of the female mold, and the male and female molds were clamped. Next, a resin melted by heating (a mixed resin of a heat-resistant grade polycarbonate resin and an ABS resin at a ratio of 4 to 6 by weight) was filled into a cavity formed by both molds through a male mold gate, and cooled and solidified. After opening the mold, 300mm in length,
200mm wide, 30mm in the depth direction, 4m radius of curvature at the corner
An intermediate molded product having a box shape of m and a decorative sheet laminated and integrated on the surface of the resin molded product was obtained. The decorative sheet was formed in the shape of a molded article, and no cracks were observed in the surface coating layer which became the surface layer of the coated molded article. This intermediate molded article is heated in an oven at 160 ° C. for 30 minutes as a post-molding heating step to further advance the curing reaction of the surface coating layer and complete it.
A coated article coated with a surface coating layer made of a cured product was obtained. The obtained coated molded article was a molded article that was hardly damaged because the surface became a hard film.

[0043]

According to the method for producing a coated molded article of the present invention, the thermosetting resin of the surface coating layer has an uncured state at the stage of the decorative sheet, so that it has thermoplasticity, and the surface of the molded article has a deep drawing. However, it is possible to produce a coated molded article in which the surface of the resin molded article is covered with the surface coating layer by forming the decorative sheet without cracking of the surface coating layer. Moreover, since the resin of the surface coating layer is cured by heat, the thermosetting reaction can be advanced by utilizing the heat at the time of simultaneous painting with injection molding. In addition, even in the case of a complicated shape, the surface coating layer can be formed as a layer in a non-fluid state, so that the thickness unevenness of the coating film which occurs in a post-coating method applied in a flow state does not occur, and the concave portion of the molded product is not formed. And the projections also have a uniform thickness. In addition, molding and coating (formation of a surface coating layer) are completed in one step. In addition, even in the case of a complicated shape, curing unevenness due to the shadow of irradiation rays generated by curing by ultraviolet irradiation or the like does not occur. And, in the form of performing vacuum molding of a decorative sheet using an injection mold as a vacuum mold as heat at the time of simultaneous injection molding painting, if the heat at the time of vacuum molding is used, by vacuum molding,
It can be applied to a molded product having a deeper drawn shape, and the thermosetting of the surface coating layer can be advanced by utilizing heat during vacuum molding. Also, if the heat curing of the surface coating layer is to be advanced both during the simultaneous painting of injection molding and during the heating step after molding,
Even when the decorative sheet is formed during simultaneous painting by injection molding, it is possible to suppress the progress of the heat curing of the surface coating layer and advance the surface coating layer so that cracks are not generated in the surface coating layer.
In addition, the heating step after molding can be easily performed, for example, by simply placing the intermediate molded article after injection molding in a high-temperature atmosphere. In addition, if the heat curing of the surface coating layer is advanced during the heating step after molding, a coated molded article covered with the surface coating layer made of a cured product can be manufactured even when heat during simultaneous injection molding and painting cannot be used. it can.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a decorative sheet that can be used in the present invention.

FIG. 2 is a conceptual diagram illustrating a coated molded product obtained by the present invention.

FIG. 3 is a conceptual diagram conceptually illustrating the method for producing a coated molded product of the present invention.

FIG. 4 is a cross-sectional view conceptually illustrating a shadow that causes uneven curing in the case of ultraviolet curing as a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Surface coating layer 2 Base material sheet 2a (Releasability) base material sheet 3 Decorative layer 4 Adhesive layer 5 Transfer layer 6 Resin molding 7 Shadow 41 Suction hole 42 Sheet clamp 43 Heater Ma Injection molding type (male type) Mb Injection mold (female mold) P Coated molded article R Ultraviolet S Decorative sheet W Intermediate molded article

Continued on the front page F term (reference) 3B005 EB09 FA04 FB13 FC08Y FC20Y GA06 4F100 AK01A AK15A AK15D AK15J AK22A AK22D AK22J AK25A AK25B AK25C AK45E AK51C AK74E AL01A AL10E08 BA04A08A08 BA05E08 HB00A HB01A HB31A JB13A JB13C JB14A JK12A JL11D 4F206 AA09J AA12 AA13 AA15 AA28 AA42 AA45 AD05 AD09 AD10 AF08 AF16 AG03 AH26 AH42 AH48 AH55 AH56 AK00 JA07 J02J05 J02 J05 J02

Claims (4)

[Claims] After inserting a decorative sheet having a surface coating layer between a pair of molds, both molds are clamped, and a cavity formed by both molds is filled with a resin in a flowing state and solidified. Let the decorative sheet adhere to the surface of the resin molded product at the same time as molding,
After the lamination, the two molds are opened and the injection molding simultaneous painting method is used to produce a coated molded product in which the resin molded product is coated with a surface coating layer made of a cured product of a curable resin. In the method, the surface coating layer in the decorative sheet is a layer of an uncured thermosetting resin and a room-temperature solid, and the heat curing of the surface coating layer is advanced by heat during injection molding simultaneous painting, A method for producing a coated molded article, wherein the surface coating layer in the coated molded article is a cured product. 2. After the decorative sheet is inserted between a pair of molds, and before the molds are clamped, the surface coating layer is formed when the decorative sheet is vacuum formed using the molds as a vacuum forming mold. Using a decorative sheet in which the temperature at which the thermosetting reaction of the thermosetting resin is performed is lower than the temperature at which the decorative sheet is heated during vacuum forming,
The method for producing a coated molded article according to claim 1, wherein the heat curing of the surface coated layer is advanced by heat at the time of vacuum forming, and the surface coated layer in the coated molded article is cured. 3. Heat-curing of the surface coating layer is first advanced halfway by heat during simultaneous injection molding painting, and then removed from the mold by simultaneous injection molding painting. 2. The method according to claim 1, further comprising heating the coated intermediate molded product by a heating step after molding to form a cured product of the surface coating layer in the coated molded product.
Or the method for producing a coated molded article according to 2. 4. After a decorative sheet having a surface coating layer is inserted between a pair of molds, both molds are clamped, and a cavity formed by both molds is filled with a resin in a fluid state and solidified. Let the decorative sheet adhere to the surface of the resin molded product at the same time as molding,
After the lamination, the two molds are opened and the injection molding simultaneous painting method is used to produce a coated molded product in which the resin molded product is coated with a surface coating layer made of a cured product of a curable resin. In the method, the heat curing of the surface coating layer is advanced by a post-molding heating step of heating the intermediate molded product, which has been removed from the mold by simultaneous painting with injection molding and coated with the resin molded product with the surface coating layer, And a method for producing a coated molded article, wherein the surface coating layer in the coated molded article is a cured product.