JP6745189B2 - Method for manufacturing synthetic resin molded body - Google Patents

Description

The present disclosure relates to a method for producing a synthetic resin molded article.

Automotive interior parts such as instrument panels, door trims, seats, ceilings, exterior parts, rail vehicle interior parts such as trims, seats, ceilings, aircraft interior parts, fittings, furniture, kitchen doors, storage doors, etc. For example, a resin molded body having a decorated surface is used for such purposes.
As a method of manufacturing a resin molded body with a design on the surface, when molding a resin, use a mold with a design with irregularities on the inner surface, and apply a transparent coating on the surface of the obtained resin molded body. And a method of arranging a skin material for forming a design in a mold, or coating a resin base material as a molding target with the skin material, and then heating and pressurizing the resin base material.

In the production of vehicle parts and the like by the conventional heat molding method, inner embossing may be performed for the purpose of giving a feeling of depth and three-dimensionality. Inner embossing is performed by, for example, laminating a transparent resin sheet layer and a resin sheet layer having a concavo-convex pattern on one side in advance to produce a skin material, and then laminating the obtained skin material to a resin molded body layer and molding. It is a processing method for manufacturing a body. Therefore, the design of the surface of the obtained molded product depends on the skin material. In addition, the transparent resin sheet in the skin material used for the inner embossing described above needs to have heat moldability, the materials and physical properties used are limited, and there is room for improvement in scratch resistance.

As a method for manufacturing outdoor molded products such as automobile bodies and exterior parts, a decorative film in which a thermoplastic resin layer, an uncured UV-curable hard coat layer, and a release film layer are laminated is used, and injection is performed. In the convex mold of the mold for molding, the thermoplastic resin layer of the decorative film is arranged so as to contact the injection molding resin, and the molten resin is press-fitted into the gap between the convex mold and the decorative film to form a molded body. After that, a method for producing a molded article in which the decorative film layer is formed on the surface by irradiating ultraviolet rays to cure the hard coat layer and then peeling off the release film is proposed (for example, Patent Document 1). 1).

Furthermore, as a method of forming a design having a brightness and a three-dimensional effect on the surface of the resin molded body, for example, a metallic ink is applied to the convex portion of the embossed thermoplastic resin layer to give a color pattern. A surface layer material on which a three-dimensional design is formed by thermocompression bonding with a thermoplastic resin layer via an adhesive layer containing metallic particles on one surface of a thermoplastic base sheet on which the ink application part is formed is proposed. (See, for example, Patent Document 2).

Japanese Patent No. 4627099 JP, 9-201928, A

In the method described in Patent Document 1, it is necessary to obtain a resin molded product having a decorative film having an uncured hard coat layer, and then irradiate it with ultraviolet rays to cure it, and the process is complicated. Since the transparent resin layer having a smooth scratch resistance is formed on the outermost surface of the molded body, it is difficult to obtain a design having a sufficient three-dimensional effect.
In the method described in Patent Document 2, it is necessary to apply the metallic ink only to the convex portions of the embossing after performing the embossing having an excellent design property. There is room.

An object of one embodiment of the present invention is to provide a skin material for a resin molded body and a synthetic resin molded body capable of forming a three-dimensional appearance on the surface of the synthetic resin molded body.
An object of another embodiment of the present invention is to provide a method for producing a synthetic resin molded product having a three-dimensional appearance and good scratch resistance.

Means for solving the above problems include the following embodiments .

<5> A step of forming a skin layer that includes a synthetic resin and has unevenness on the surface, and a synthetic resin, a metallic pigment, and a color other than the metallic pigment on the surface of the skin layer opposite to the uneven surface. And a step of forming a skin base material layer containing an agent, to obtain a skin material for resin molded body, the surface material of the resin molded body, the resin molding base material and the skin base material on the surface of the resin molded base material. The step of arranging so that the material layer is in contact with the material layer to obtain a preform by heat-molding, and by applying a transparent resin to the surface of the resin-molded body skin material arranged in the obtained preform to make it transparent. A method for producing a synthetic resin molded body, which has a step of forming a resin layer, and obtains a synthetic resin molded body having a resin molded base material, a skin base material layer, a skin layer, and a transparent resin layer in this order.
<6> The method for producing a synthetic resin molded article according to <5>, further including a step of forming an adhesive layer between the resin molded substrate and the skin substrate layer.
<7> The step of applying the transparent resin to form the transparent resin layer includes the step of applying the composition for forming a transparent resin layer onto the surface of the skin material for resin molding <5> or <6>. The method for producing a synthetic resin molded body according to 1.

According to one embodiment of the present invention, it is possible to provide a skin material for a resin molded body and a synthetic resin molded body capable of forming a three-dimensional appearance on the surface of the synthetic resin molded body.
According to another embodiment of the present invention, it is possible to provide a method for producing a synthetic resin molded body having a three-dimensional appearance and good scratch resistance.

It is a partial schematic sectional view showing a layer composition of a synthetic resin molding which is one embodiment of the present invention.

The numerical range described by using "to" in the present specification represents a numerical range including the numerical values before and after "to" as the lower limit value and the upper limit value.
In the present specification, the term “process” is included not only in an independent process but also in the case where the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes.
Furthermore, in the present specification, the amount of each component in the composition is the total amount of the plurality of substances present in the composition, unless a plurality of substances corresponding to each component are present in the composition. Means

Hereinafter, the present invention will be described in detail.
[Skin material for resin moldings]
The skin material for a resin molded body in the present disclosure (hereinafter, may be simply referred to as “skin material”) is a skin base material layer containing a synthetic resin, a metallic pigment, and a colorant other than the metallic pigment, and A skin layer is provided on one surface of the skin base layer, contains a synthetic resin, and has a skin layer having irregularities on the surface opposite to the surface facing the skin base layer. That is, the skin material is a skin material having a laminated structure having at least a skin base material layer and a skin layer in this order from the side in contact with the resin molding base material.
INDUSTRIAL APPLICABILITY The skin material for a resin molded body of the present disclosure has a three-dimensional design and is excellent in appearance by manufacturing a synthetic resin molded body accompanied by heating, such as press molding (compression molding), injection molding, and vacuum molding. It is preferably used for manufacturing a synthetic resin molded body.

By disposing the skin material of the present disclosure on the surface of the resin-molded substrate and performing heat molding, a preform having the skin material for resin-molded body on the surface of the resin-molded substrate can be obtained. By further forming a transparent resin layer on the surface of the obtained preformed body, it is possible to obtain a synthetic resin molded body in the present disclosure to be described later, which has a three-dimensional design and good surface properties with scratch resistance. it can.
By using the skin material of the present disclosure, in the conventional skin material, the problem of moldability in the case of using the skin material having the transparent resin layer on the outermost surface from the beginning, the three-dimensional effect in the case of forming the transparent resin layer after molding. It is possible to obtain a synthetic resin molded product which has a three-dimensional effect and is excellent in scratch resistance, while suppressing the occurrence of problems such as deterioration of The method for manufacturing the synthetic resin molded body will be described later.
Hereinafter, each layer of the skin material for a resin molded body will be described.

[Episode base material layer]
The skin base material layer contains a synthetic resin as a base material of the resin layer, a metallic pigment useful for imparting a three-dimensional effect, and a colorant other than the metallic pigment.

(Synthetic resin)
The synthetic resin contained in the surface material is not particularly limited as long as it is a resin capable of forming a film or sheet by a known forming method such as a calendering method and a melt extrusion method. Examples of the synthetic resin that can be used for forming the skin base material layer include vinyl chloride resin, acrylic resin, polyurethane, and olefin resin.
Among them, a synthetic resin selected from the group consisting of vinyl chloride resin, acrylic resin, and polyurethane is preferable, and vinyl chloride resin is more preferable, from the viewpoints of easiness of processing, flexibility of the obtained skin material, and the like.

As the vinyl chloride resin that can be used for the skin base material layer, any resin that has been conventionally used for vinyl chloride leather can be used without particular limitation. Specific examples thereof include polyvinyl chloride having an average degree of polymerization of 800 to 2000, preferably about 800 to 1500. Further, mainly vinyl chloride, ethylene, vinyl acetate, a copolymer resin with a methacrylic acid ester, a vinyl chloride homopolymer resin or a copolymer resin containing vinyl chloride, a polyester resin, an epoxy resin, an acrylic resin, Examples thereof include a mixed resin with at least one resin selected from vinyl acetate resin, urethane resin, acrylonitrile, styrene-butadiene copolymer resin, partially saponified vinyl alcohol and the like.

Examples of the acrylic resin that can be used for the skin base material layer include a polymer or copolymer of methacrylic acid or a methacrylic acid ester represented by polymethyl methacrylate (PMMA), a copolymer of alkyl methacrylate, an alkyl acrylate, and styrene. From the viewpoint of moldability, copolymers of alkyl methacrylate, alkyl acrylate, and styrene, and mixtures of methyl methacrylate and methyl acrylate copolymers are listed.

Polyurethanes that can be used in the skin base material layer include polycarbonate polyurethanes, polyether polyurethanes, polyester polyurethanes and modified products thereof. Of these, polycarbonate-based polyurethane and the like are preferably used when long-term durability is required for automobile interior materials and the like.

Examples of the olefin resin that can be used in the skin base material layer include a resin containing a structural unit derived from an olefin monomer selected from polyethylene, polypropylene, etc., ethylene, propylene, and α-olefins having 4 to 10 carbon atoms as a polymerization component. ..

The epidermis base material layer may contain only one kind of synthetic resin, or may contain two or more kinds thereof.

(Metallic pigment)
The skin base material layer contains a metallic pigment. As an aspect including the metallic pigment in the skin base material layer, an aspect including the metallic pigment in the skin base material layer, and forming a resin layer containing no metallic pigment, the metallic layer on the side in contact with the skin layer of the resin layer. A mode in which a pigment-containing layer is provided is included. In the case of containing a metallic pigment in the skin base material layer, the skin base material layer has a single layer structure, in the latter case where the metallic pigment is provided as a separate layer, in the latter case, the skin base material layer is a resin layer containing no metallic pigment and a metallic pigment. It has a laminated structure of containing layers.
Among them, the skin base material layer preferably has a single layer structure containing a metallic pigment from the viewpoint of ease of production.

The metallic pigment that can be used in the skin base material layer is not particularly limited as long as it is a pigment that can impart glitter and luster to the formed resin layer. Examples of the metallic pigments include metallic pigments having a luster, pearl pigments, mica and the like.
Examples of the metallic pigment having luster include an aluminum pigment and a silver pigment.
Examples of the pearl pigment include titanium oxide-coated mica (titanium mica), titanium oxide-coated glass flakes, and titanium oxide-coated talc.
Among them, from the viewpoints of good brightness feeling and better durability, the metallic pigment in the present disclosure is preferably a high brightness metal pigment such as an aluminum pigment or a silver pigment.

The skin base material layer may include only one type of metallic pigment, or may include two or more types of metallic pigment.
When the skin base material layer is formed of a composition for forming a skin base material layer containing a synthetic resin, a metallic pigment and another colorant, the content of the metallic pigment is equal to that of the composition for forming a skin base material layer. It is preferably 0.25% by mass or more and 30% by mass or less, and more preferably 1% by mass or more and 20% by mass or less, based on the total solid content.
When the content of the metallic pigment is 0.25% by mass or more, the brightness of the skin base material layer becomes good, and a three-dimensional effect is obtained even after forming the transparent resin layer on the surface of the skin layer having irregularities. Easy to maintain design. When the content of the metallic pigment is 30% by mass or less, it becomes easy to obtain a uniform and sufficient strength skin base material layer.

Further, in the case of forming a skin base material layer having a resin layer containing no metallic pigment and a metallic pigment-containing layer, after forming a resin layer containing no metallic pigment by a conventional method, the above-mentioned metallic pigment and film-forming property are formed. A method for preparing a composition for forming a metallic pigment-containing layer containing a resin having, and applying the composition on the side of the resin layer not containing the metallic pigment to form the skin layer, or a known metallic coating material for the resin layer, a metallic ink. Means such as a method of applying the like can be used.

Examples of the resin that can be used for forming the metallic pigment-containing layer include known film-forming resins such as polyurethane, vinyl chloride resin, and acrylic resin.
From the viewpoint of effects, silver metallic ink is preferable as the metallic paint and metallic ink that can be used for forming the metallic pigment-containing layer.
A commercially available product can be used as the metallic ink. Examples of commercially available metallic inks that can be used to form the metallic pigment-containing layer include, for example, Dainichiseika Kogyo Co., Ltd., metallic printing ink LR-Ki series, Megami Ink Kogyo Co., Ltd., metallic ink series, DIC, metallic. Examples include ink.

(Colorants other than metallic pigments)
The skin base material layer contains a colorant other than the metallic pigment described above (hereinafter, may be referred to as other colorant).
Since the skin base material layer contains a colorant other than the metallic pigment in addition to the metallic pigment, an arbitrary hue can be imparted to the skin material, so that the degree of freedom in designing the skin material is improved.
As the other coloring agent, from the viewpoint that the decrease in the brightness of the skin base material layer due to the metallic pigment is suppressed, and the skin base material layer is clearly visible in a colored state, visible light is used. It is preferable to use a colorant that is difficult to block.
Examples of other colorants that can be included in the skin base material layer include dyes and pigments having a fine particle size.
The dye is preferably a dye having a hue that does not easily inhibit the transmission of visible light, and the pigment has a particle size that hardly causes light reflection, for example, an average primary particle size of 0.7 μm or less, and more preferably 0.4 μm or less of an average particle. Diameter pigments.
The average primary particle diameter of the pigment is obtained by observing with a scanning microscope (SEM) or a transmission microscope (TEM), measuring 100 particle sizes in the area where the particles are not aggregated, and calculating the average value. be able to.

From the viewpoint that the effect of the skin material, which is an embodiment of the present invention, is better exhibited and the durability is better, it is preferable to use a pigment other than the metallic pigment as the other colorant.
The hue of the other colorant is arbitrary, and a colorant having a suitable hue appropriately selected according to the purpose may be used.
The pigment that can be used in the present invention may be either an organic pigment or an inorganic pigment.
Examples of pigments that can be used as other colorants are shown below, but are not limited to the examples shown below.
Examples of the organic pigment include the following.
C. I. Pigment Yellow 11,24,108,109,110,138,139,150,151,154,167,180,185,
C. I. Pigment Orange 36,71,
C. I. Pigment Red 122,150,171,175,177,209,224,242,254,255,264,
C. I. Pigment Violet 19, 23, 32,
C. I. Pigment Blue 15:1, 15:3, 15:6, 16, 22, 60, 66,
C. I. Pigment Brown 25, 28,
C. I. Pigment Green 7,36,37,
C. I. Pigment Black 1,

Examples of the inorganic pigment include carbon black (CI Pigment Black 8), titanium black, titanium white, calcium carbonate, barium sulfate, and aluminum hydroxide.

When a pigment is used as the other colorant, it is preferable to use a known dispersant suitable for the pigment used and the synthetic resin as the dispersion medium. By using the dispersant, it is possible to further improve the dispersibility of the pigment as the other colorant and the metallic pigment described above in the synthetic resin that serves as the dispersion medium of the pigment in the skin base material layer. For example, it is preferable from the viewpoint of uniform dispersibility of the pigment to form the skin base material layer by using a mixture of a metallic pigment and a pigment which is another colorant, a dispersant and a synthetic resin in advance.

The epidermis base material layer may contain only one kind of the other colorant, or may contain two or more kinds thereof.
The content of the other colorant in the skin base material layer is preferably more than 0 mass% and 50 mass% or less, and preferably 1 mass% or more, with respect to the total solid content of the composition for forming the skin base material layer. It is more preferably 40% by mass or less.
When the content of the other colorant exceeds 0% by mass, it becomes easier to obtain a clear hue in the skin base material layer, and when the content of the other colorant is 50% by mass or less, the metallic pigment is contained. It is possible to obtain a design having a more three-dimensional effect, because the effect of doing so is not easily impaired.

The skin base material layer may contain, in addition to the synthetic resin, the metallic pigment, and the other colorant, known additives (hereinafter, referred to as other components) depending on the purpose as long as the effects of the present disclosure are not impaired. it can.
Other components that can be contained in the skin base material layer include a plasticizer, a lubricant, a film-forming aid, and a foaming agent.

The skin base material layer is a synthetic resin, a metallic pigment, and a colorant other than the metallic pigment, and further, a composition for forming a skin base material layer containing a known additive to be optionally contained is prepared, and the obtained skin base material is obtained. It can be formed by molding the layer-forming composition into a sheet by a known molding method such as a calendar method or a casting method.

As described above, when the skin base material layer has a resin layer that does not contain a metallic ink and a metallic pigment-containing layer, the metallic pigment-containing layer is formed into a sheet by the method described above, and then the formed metallic layer is formed. A resin layer containing no metallic ink can be formed on the surface of the pigment-containing layer by applying a known coating method.

The film thickness of the epidermis base material layer is not particularly limited, and when the epidermis base material layer is a single layer, for example, it is preferably in the range of 50 μm to 300 μm, and more preferably in the range of 100 μm to 200 μm. It is more preferably in the range of 100 μm to 150 μm. When the thickness is in the above range, when forming a synthetic resin molded article using a skin material, the three-dimensional effect due to the skin base material layer containing the metallic pigment and other colorants becomes clearer, and the designability is improved. Will be better.

When the skin base material layer has a resin layer containing no metallic pigment and a layer containing a metallic pigment, the thickness of the resin layer containing no metallic pigment is preferably in the range of 1 μm to 500 μm, and more preferably in the range of 50 μm to 300 μm. ..
The thickness of the metallic pigment-containing layer is preferably in the range of 50 μm to 300 μm, more preferably in the range of 100 μm to 150 μm, from the viewpoint that it is easier to obtain a three-dimensional effect.

[Skin layer]
A skin layer has a skin layer on one surface of the skin base material layer. The skin layer is provided on one surface of the skin base material layer, contains a synthetic resin, and has irregularities on the surface opposite to the surface skin base material layer. The shape of the unevenness, the arrangement interval, etc. are appropriately selected depending on the design on the surface of the molded body. The unevenness may be, for example, a continuous pattern such as a lattice pattern or a stripe, or may be a discontinuous pattern such as a dot pattern or a camouflage pattern.

The synthetic resin contained in the skin layer is not particularly limited, but contains at least one resin selected from acrylic resin and fluororesin from the viewpoint of good retention of formed irregularities and good scratch resistance. It is preferable.
There is no particular limitation on the aspect in which the skin layer contains at least one resin selected from a fluororesin and an acrylic resin, and for example, a fluorine atom-containing acrylic resin in which a part of hydrogen atoms in the acrylic resin is replaced with a fluorine atom is used. Examples include a mode of use, a mode of using a mixture of a fluororesin and an acrylic resin, a mode of using a mixture of a fluororesin and a fluorine atom-containing acrylic resin, and a mode having a multi-layer structure of a fluororesin-containing layer and an acrylic resin-containing layer. ..
Among them, the skin layer preferably contains a fluororesin and an acrylic resin from the viewpoint that the obtained synthetic resin skin material has better gloss, scratch resistance, and stain resistance.

(acrylic resin)
As the acrylic resin that can be contained in the skin layer, for example, a polymer or copolymer of methacrylic acid or a methacrylic acid ester represented by polymethyl methacrylate (PMMA), a copolymer of alkyl methacrylate, an alkyl acrylate and styrene. From the viewpoint of moldability, copolymers of alkyl methacrylate, alkyl acrylate and styrene, mixtures of methyl methacrylate and methyl acrylate copolymers, and the like can be mentioned.
It may also be a fluorine-modified acrylic resin.

(Fluorine resin)
The fluororesin that can be contained in the skin layer refers to a resin containing one or more fluorine atoms in the molecule, and examples thereof include a resin in which hydrogen atoms in an olefin resin are replaced by fluorine atoms.
Examples of the fluororesin include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylene propylene resin, ethylene-tetrafluoroethylene copolymer, vinylidene fluoride resin and the like.

The method of forming the skin layer is not particularly limited, and a known layer forming method may be applied.
The thickness of the skin layer is preferably in the range of 10 μm to 100 μm, and more preferably in the range of 30 μm to 70 μm.
The thickness of the skin base material layer in the skin material is preferably thicker than that of the skin layer, from the viewpoint that the three-dimensional appearance of the obtained design becomes better.
The skin layer is preferably transparent in order to reflect the appearance due to the metallic pigment in the skin base material layer. Here, the term "transparent" means that the transmittance of light having a wavelength in the visible region is 80% or more, and preferably 90% or more.
The transmittance of light having a wavelength in the visible range in the epidermis layer can be confirmed by the absorbance measured using a spectrophotometer.
The absorption characteristics and the transmittance are measured, for example, by using an absorptiometer (also referred to as a spectrophotometer; spectrophotometer UV-3100 manufactured by Shimadzu Corporation) to measure an absorption spectrum or a transmittance spectrum of light having a wavelength of 400 to 700 nm. You can ask for it.
The transmittance is a value calculated by the following formula from the absorbance.
Transmittance=100/(10^(absorbance))

As a method for forming irregularities on the surface of the skin layer on the side opposite to the surface of the base material layer, any known irregularity forming method can be applied. For example, a method of applying a skin layer forming resin to the surface of a release material on which unevenness has been formed in advance and transferring the unevenness of the release material to the surface of the skin layer, or contacting a squeeze roll with unevenness on the skin layer. A method of transferring the unevenness of the squeezing roll to the skin layer by applying pressure and heat to laminate embossing, and the like. When applying the transfer method, the unevenness may be formed and the bonding may be performed at the same time.
By forming the unevenness on the squeeze roll in advance and applying the transfer method of laminating embossing using the squeeze roll, the lamination of the skin layer and the skin base material layer and the texture pressing to the skin layer, that is, the uneven pattern The formation can be done in one step.

In forming the skin layer, the heating temperature in the laminating embossing in any one of the sequential forming method of the skin layer and the skin base material layer and the one-step formation method using the laminate of the skin layer and the skin base material layer is , 100-190 degreeC is suitable.
The skin material in the present disclosure is useful for forming a design having a three-dimensional appearance on the surface of a resin molded body, the appearance is not impaired even after molding by heating, and the moldability is good, so that the synthesis involving heating and pressing is performed. It is useful for forming a resin molding.

In addition to the above-mentioned synthetic resins, the skin layer may contain known additives (sometimes referred to as other components) depending on the purpose.
Other components that the skin layer may include include matting agents, plasticizers, lubricants, film-forming aids, and the like.

[Synthetic resin molding]
By disposing the skin material obtained as described above on the surface of the resin-molded substrate and molding the resin, a transparent resin layer is formed to obtain a resin-molded article having a three-dimensional appearance. ..
The synthetic resin molding according to the present disclosure has the above-described skin material for resin molding and the transparent resin layer on the surface of the resin molding substrate.
FIG. 1 is a partial schematic cross-sectional view showing a layer structure of a synthetic resin molded body which is an embodiment of the present invention.
The synthetic resin molded body 10 shown in FIG. 1 has the above-mentioned skin material 14 for resin molded body and the transparent resin layer 24 on the surface of the resin molded substrate 12. In FIG. 1, an adhesive layer 16 and a primer layer 18 are provided on the surface of the resin-molded base material 12 for the purpose of improving adhesion, and the resin-molded base material 12 includes the adhesive layer 16 and the primer layer 18. It is in close contact with the skin base material layer 20 of the skin material 14 via the interposition. A skin layer 22 having irregularities is provided on the surface of the skin base layer 20 opposite to the resin-molded base 12. The surface of the skin layer 22 preferably has a transparent resin layer 24 provided by coating.
In FIG. 1, the adhesive layer 16 and the primer layer 18 are arbitrary layers provided from the viewpoint of improving the durability of the obtained synthetic resin molded body 10.
Known skin materials generally include a skin base material layer, a skin layer, and a transparent resin layer, and the degree of freedom in prescribing the transparent resin layer is not sufficient in order to impart moldability to the transparent resin layer. There is a problem. The skin material according to the present disclosure does not have a transparent resin layer, and thus has good thermal processability. Then, as described below, in the preferred method for producing a synthetic resin molded article according to the present disclosure, in order to form the transparent resin layer after the formation of the preformed article obtained by heat-molding the resin molding substrate and the skin material. For example, it is possible to easily provide a transparent resin layer having an arbitrary composition according to the purpose, such as a hard coat layer and the like, which has poor thermal processability but is excellent in scratch resistance and durability.

[Resin molding base material]
The resin molding base material 12 in the synthetic resin molding is a molding base material having a shape, size, weight and the like according to the intended synthetic resin molding body 10, and the skin material 14 is arranged along the surface thereof. The synthetic resin molded body 10 in which the skin material 14 and the resin molding base material 12 are bonded and molded through the adhesive layer 16 and the primer layer 18 which are arranged as desired to form a design having a three-dimensional effect is formed. obtain.
The material, shape, size, etc. of the resin molded substrate 12 may be selected in consideration of the use, purpose, design, cost, etc. of the molded body to be manufactured.

[Transparent resin layer]
The transparent resin layer in the synthetic resin molded body is formed in a range that does not impair the design and three-dimensional appearance of the skin material.
The resin used for forming the transparent resin layer can be used without particular limitation as long as the formed layer has high transparency and can provide necessary physical properties such as scratch resistance. In addition, that the resin layer is transparent means that, after the transparent resin layer is formed, a concavo-convex pattern on the surface of the lower surface skin material can be visually recognized through the transparent resin layer.
Among them, an ultraviolet curable resin composition capable of forming a hard coat layer having good scratch resistance is preferable.

The ultraviolet curable resin composition that is preferably used for forming the transparent resin layer will be described. The ultraviolet curable resin composition can be selected from materials that can be cured by ultraviolet irradiation to form a transparent resin layer as a hard coat layer having scratch resistance. Specifically, for example, a composition containing at least one kind of a polymerizable monomer such as urethane acrylate and an acrylic monomer and a radical type photopolymerization initiator can be mentioned.

The method of applying the ultraviolet-curable resin composition to the surface of the skin material having the irregularities is not particularly limited. A known coating device can be used. Above all, a method of coating the surface of the skin material having irregularities by a coater method is preferable. Although it can be applied by a spray coating method or the like, the coating method is preferable from the viewpoint of suppressing the loss of the ultraviolet curable resin composition and more efficiently and uniformly applying it. It is preferable to form an ultraviolet-curable resin composition layer on the surface of the skin material by a coating method and then dry it. Among them, the direct reverse coater method is preferable from the viewpoints of uniformity of layer thickness and surface smoothness. Drying is preferably performed by applying air and then drying after coating.

The thickness of the transparent resin layer is appropriately determined depending on the application of the synthetic resin molded body and the like. Among them, the thickness after curing is preferably, for example, 5 μm to 50 μm, and more preferably 10 μm to 30 μm, from the viewpoint of ensuring scratch resistance and smoothness of the transparent resin layer after being cured by UV irradiation. preferable.
The formed transparent resin layer has a hardness after curing and is scratch-free with a sapphire needle of 30 g, or has a scratch resistance of H or more in a pencil hardness according to JIS K-5400 (1990) pencil scratch test. It is preferable.

The UV-curable resin composition layer for forming the transparent resin layer may be formed by a coating method as described above, but the uncured UV-curable resin composition layer is a surface having irregularities in the skin material. It may be imparted by a transfer method as long as it has physical properties capable of following the irregularities of the skin material when it is brought into close contact with. In the case of applying the ultraviolet curable resin composition layer on the surface of the skin material by the transfer method, after forming the ultraviolet curable resin composition layer on the ultraviolet-transparent temporary support, after adhering to the skin material The cured transparent resin layer can be formed by irradiating with ultraviolet rays through the temporary support or after peeling the temporary support.
The ultraviolet-transparent temporary support preferably has a mirror-like property from the viewpoint of ensuring the surface smoothness of the molded product during ultraviolet irradiation and peeling of the temporary support, in addition to ultraviolet transparency and releasability.
Further, those having extensibility are preferable from the viewpoint of preventing the occurrence of wrinkles due to uneven elongation during molding.
Specific examples of the temporary support include a polyethylene (PE) film, a polypropylene (PP) film, and a polyethylene terephthalate (PET) film. Among them, PE film and PP film are preferable, and low-density polyethylene (LDPE) clear film is particularly preferable, from the viewpoint of moldability at low temperature.
The thickness of the temporary support is not particularly limited as long as it has the required strength. For example, a film having a thickness of 100 μm to 200 μm is preferable.

[Other layers that the synthetic resin molded body may have]
As shown in the partial schematic cross-sectional view of FIG. 1, a synthetic resin molded body 10 according to the present disclosure includes a resin molded base material 12 and a resin molded base body as described above, which is disposed on the surface of the resin molded base material 12. In addition to the skin material 14 and the transparent resin layer 24, other layers may be provided depending on the purpose as long as the effect is not impaired. Examples of the other layer include an adhesive layer and a primer layer.
In one embodiment shown in FIG. 1, an adhesive layer 16 is provided on the surface of a resin molded substrate 12, and a primer layer 18 is provided for the purpose of improving the adhesiveness between the adhesive layer 16 and the skin material 14. ing. The adhesive layer 16 and the primer layer 18 in FIG. 1 are other layers provided according to the purpose.

(Adhesive layer)
The adhesive layer 16 can be formed by disposing the skin material 14 along the surface of the resin-molded substrate 12 and applying an adhesive to the surface of the resin-molded substrate 12 before molding.

The adhesive used for forming the adhesive layer is not particularly limited and is appropriately selected depending on the type of the resin molding substrate 12 and the like. For example, (1) two-component curable polyester adhesive, (2) two-component curable urethane adhesive, and (3) two-component curable acrylic pressure-sensitive adhesive are preferably used.
The adhesive used for forming the adhesive layer is also available as a commercial product. For example, Olivaine series [Toyo Ink Co., Ltd.], Welder adhesive No. 3660 [two-component curing type polyurethane-based adhesive: No-Tape Kogyo Co., Ltd.], Daikarac 7250NT [two-component curing type polyester-based adhesive: Daido Kasei Co., Ltd.] and the like are preferable.
The adhesive layer 16 preferably has a dry film thickness in the range of 20 μm to 50 μm.

Although the adhesive layer 16 is provided between the resin molding substrate 12 and the primer layer 18 in FIG. 1, the adhesive layer 16 is not limited to this, and the adhesiveness of each layer is not impaired unless the effect of the present disclosure is impaired. It may be provided between arbitrary layers for the purpose of improving

(Primer layer)
The synthetic resin molded body 10 in the present disclosure may have a primer layer 18. The primer layer 18 is a layer that is provided as necessary in order to improve the adhesion between the resin molding substrate 12 and the skin material 14, or the adhesive layer 16 that is an arbitrary layer and the skin material 14. ..
The primer layer 18 is made of a material that improves adhesion between the skin material 14 and the resin-molded base material 12 or the like, similarly to the formation of the adhesive layer 16 described above, which is optionally provided on the surface of the resin-molded base material 12. The primer layer 18 can be formed by coating the surface of the material 14 on the surface of the base material layer 20 side. Specifically, for example, it can be formed by applying a urethane-based paint on the surface of the skin material 14 on the skin base material layer 20 side and drying.

The primer layer 18 may include only one type of material that improves the adhesiveness with the adjacent layer described above, or may include two or more types of materials.
The thickness of the primer layer 18 is not particularly limited. Usually, it is 1 μm to 5 μm, preferably 2 μm to 3 μm.

(About synthetic resin moldings)
Since the synthetic resin molded body 10 according to the present disclosure includes the skin material 14 and the transparent resin layer 24 having the above-described configuration on the surface of the resin molded base material 12, the skin base material layer 20 and the skin layer 22 are provided. The functions of the skin material 14 and the transparent resin layer 24 are combined to form a synthetic resin molded body 10 having a smooth surface, good scratch resistance, and a three-dimensional design formed on the surface and having an excellent appearance. , Its application range is wide.

[Method for producing synthetic resin molding]
The synthetic resin molded article according to the present disclosure includes a synthetic resin, and a step of forming a skin layer having unevenness on the surface [step (A)], a synthetic resin is formed on a surface of the skin layer opposite to the uneven surface. A step of forming a skin base material layer containing a resin, a metallic pigment, and a colorant other than the metallic pigment to obtain a skin material for a resin molded body [step (B)], on the resin molded base material surface, A step of arranging a skin material for a resin molded body so that the resin molding base material and the skin base material layer are in contact with each other to obtain a preformed body by heat molding [step (C)], and the obtained preforming There is a step [step (D)] of forming a transparent resin layer by applying a transparent resin on the surface of the skin material arranged on the body, and a resin molding substrate, a skin substrate material layer, and a skin layer. And a transparent resin layer in this order to obtain a synthetic resin molded body.

[Step of forming a skin layer containing a synthetic resin and having irregularities on the surface: step (A)]
In step (A), a skin layer containing a synthetic resin is formed. A concavo-convex pattern (hereinafter sometimes referred to as a grain) is formed on one surface of the skin layer to enhance design.
The skin layer can be formed by forming a skin layer-forming composition containing a synthetic resin. The unevenness is, for example, as described above, the composition for forming a skin layer is applied to a release material on which unevenness is formed in advance, a composition layer for forming a skin layer is formed, and one side is formed by peeling the release material. It is possible to form a skin layer having irregularities on the surface of the.
Further, the composition for forming a skin layer is applied to a smooth release material to form a composition layer for forming a skin layer having no unevenness, and then the step (B) described below is performed to form the composition for forming a skin layer. A composition layer for forming a skin base material layer is provided by applying a composition for forming a skin base material layer on the surface of the layer opposite to the release material, and a composition layer for forming a skin layer and a skin base material layer are formed. By laminating and embossing the laminate with the composition layer with a squeezing roll, the skin layer and the skin base material layer are brought into close contact, and the surface of the skin layer opposite to the side having the skin base material layer is uneven. Can also be formed.
The details of the composition for forming the skin layer, the preferable film thickness and the like are as described above.

[A synthetic resin, a metallic pigment, and a coloring agent other than the metallic pigment, on a surface opposite to the side having the unevenness of the skin layer, a skin base material layer is formed to form a skin material for a resin molded body. To obtain: step (B)]
In the step (B), a composition for forming a skin base material layer, which includes a synthetic resin, a metallic pigment, and a coloring agent other than the metallic pigment on the surface of the skin layer on the side having no unevenness (without forming the unevenness). The composition is applied to form a composition layer for forming a skin base material layer, and then the composition layer for forming a skin base material layer is dried and cured to form a skin base material layer.
Details of the composition for forming the skin base material layer, preferable film thickness, and the like are as described above.

By carrying out the step (A) and the step (B), the skin material according to the present disclosure is obtained. The following methods may be used to form the skin material.
For example, the step (A) and the step (B) may be separately performed as independent steps, and then the obtained skin layer and the skin base material layer may be brought into close contact with each other to obtain a skin material.
In addition, first, the step (B) is performed to form a composition layer for forming a skin base layer, and a composition layer for forming a skin layer containing a synthetic resin is provided on one surface of the composition layer for forming a skin base layer. Formed, the resulting laminate is laminated and embossed with a squeezing roll to provide irregularities on the surface of the skin layer opposite to the surface in contact with the skin base material layer, and the skin layer and the skin base material layer. The skin material can be obtained by closely contacting.
Furthermore, a composition layer for forming a skin layer is formed on the surface of the release material on which a die is formed, and a composition for forming a skin base material layer is formed on the surface of the formed composition layer for forming a skin layer opposite to the release material. A material layer is formed, cured, and the release material is peeled off to obtain a skin material including a skin layer having irregularities and a skin base material layer.

[Step of disposing a skin material for a resin molded body on the surface of the resin molded base material so that the resin molded base material and the skin base material layer are in contact with each other and performing heat molding to obtain a preformed body: step (C)]
In step (C), the surface of the resin-molded substrate is brought into contact with the surface of the skin material obtained in steps (A) and (B), and the surface is heat-molded by a conventional method to obtain the surface. The skin material is fixed to the preform to obtain a preform molded into a desired shape.
The resin molding substrate is a molding substrate having a shape, size, weight, etc. according to the intended synthetic resin molded body, and the above-mentioned skin material is arranged along the surface thereof, and is molded, A synthetic resin molded body having a three-dimensional design is obtained.
The material, shape, size, etc. of the resin molded substrate 12 may be selected in consideration of the use, purpose, design, cost, etc. of the molded body to be manufactured.
For the heat molding, a known molding method may be selected according to the purpose. Examples of the heat molding method include press molding (compression molding), injection molding, vacuum molding, membrane molding, and TOM molding.

By performing a molding method utilizing a pressure difference of atmospheric pressure such as vacuum molding, membrane molding, and TOM molding, it is possible to obtain a synthetic resin molded article having good adhesion of the skin material at a relatively low temperature.
The TOM (Three Dimension Overlay Method) molding removes air from a resin-molded base material and a skin material, which have been molded in advance with a resin or the like, under a vacuum environment, and decorates the molded body through processes such as heating, molding, and pressing. Is the way. The TOM molding does not require an injection step at high temperature, and a rigid resin molded product having a design with a desired three-dimensional effect can be manufactured at low temperature.
When obtaining the preformed body, the skin material may be arranged on the surface of the resin-molded substrate or may be arranged in the molding die.

[Step of forming a transparent resin layer by applying a transparent resin to the surface of the skin material arranged on the obtained preformed body [step (D)]
The preform obtained in the step (C) has a surface of a resin-molded substrate, a skin-based substrate layer containing a metallic pigment and the like, and a skin layer having irregularities on the outermost surface, which are It has the skin material which has in order. In the step (D), a transparent resin is applied to the outermost surface of the uneven skin material to form a transparent resin layer.
The step of applying the transparent resin to form the transparent resin layer is a step of applying the composition for forming the transparent resin layer on the surface of the skin material for the resin molded body, thereby obtaining a more three-dimensional design. It is preferable from the viewpoint.

For example, an ultraviolet curable resin composition, which is a preferred example of the transparent resin layer forming composition, will be described as an example. The ultraviolet curable resin composition was applied to the surface of the skin material having the irregularities by a coater method to form an ultraviolet curable resin composition layer that was a composition layer for forming a transparent resin layer on the surface of the skin material. Thereafter, by drying, a layer having a uniform layer thickness and a smooth surface is formed. As the coater method, the direct reverse coater method is preferable from the viewpoint of uniformity of the coating film.
Drying of the ultraviolet curable resin composition layer is preferably performed in a non-contact manner while applying air.
A transparent resin layer having excellent scratch resistance can be obtained by applying energy to the ultraviolet curable resin composition layer by ultraviolet irradiation to cure the ultraviolet curable resin composition layer.
The light source that radiates ultraviolet rays is not particularly limited as long as it can radiate ultraviolet light in the wavelength range that cures the transparent resin layer, and an LED (light emitting diode) light source, a high pressure mercury lamp, a black light, or the like can be adopted.

Usually, when a transparent resin layer is provided on the surface of the skin material 14 having irregularities, the surface becomes smooth, and the visibility of the three-dimensional effect due to the irregularities provided on the skin material 14 may deteriorate. In the synthetic resin molded body 10 of one embodiment of the present invention, by providing the skin material 14 having the skin base material layer 20 having a metallic pigment or the like under the skin layer 22 having irregularities, a three-dimensional design is impaired. It is believed that the realization of the three-dimensional design and the smoothness of the surface, the mirror surface property, the scratch resistance, etc., which are not caused by the provision of the transparent resin layer 24 after the formation of the preformed body are compatible with each other at a high level. There is.

[Arbitrary process]
The method for producing a synthetic resin molded body according to the present disclosure may further include any step in addition to the step (A), the step (B), the step (C) and the step (D).
For example, the method may further include a step of forming an adhesive layer on the surface of the resin molded substrate. By having the adhesive layer on the surface of the resin-molded substrate, the adhesion between the resin-molded substrate and the skin material is improved, and a synthetic resin molded product having better durability can be manufactured.
The method for forming the adhesive layer 16 on the surface of the resin molded substrate 12 is not particularly limited, and a known method such as a spraying method, a coating method using a coater, or a transfer method can be employed.
The method for forming the adhesive layer may be selected according to the type of adhesive, the type of resin contained in the resin molding base material, the shape of the resulting molded body, and the like.

Further, a step of providing the primer layer 18 between the adhesive layer 16 and the skin base material layer 20 of the skin material 14 may be included.
The primer layer improves the adhesion between the resin molding base material or the adhesive layer and the skin material 14 on the surface of the resin molding base material to which the skin material is applied, simultaneously with the adhesive layer or sequentially. It can be formed by applying a material. Specifically, for example, a method of forming a primer layer by gravure-coating a urethane-based paint, which is a material for improving the adhesiveness, on the surface of the skin material on which the resin-molded base material is adhered, and drying with hot air is used. Can be mentioned.

(About manufacturing method of synthetic resin molding)
According to the manufacturing method of the present disclosure, a synthetic resin molded product having a three-dimensional appearance and good scratch resistance can be manufactured in a simple process.
The obtained synthetic resin molded article can be applied to the production of various products which are required to have a surface scratch resistance and a design property having a three-dimensional effect. For example, automobiles, railway vehicles, aircraft interior materials and exteriors. It can be suitably used in various fields such as materials, fittings, furniture, kitchen doors, and storage doors.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

<Example 1>
[Manufacture of synthetic resin molding]
(Preparation of skin material)
To 100 parts by mass of vinyl chloride resin [S1001N (trade name) Kaneka Co., Ltd.], 5 parts by mass of metallic pigment (6320NS: product name, manufactured by Toyo Aluminum Co., Ltd.) and 5 parts by mass of carbon black which is a colorant other than the metallic pigment. Parts and then mixed while heating at 200° C. to prepare a composition for forming a skin base material layer, and the obtained composition for forming a skin base material layer has a thickness after drying of 150 μm by a calendering method. Thus, a skin-shaped base material layer containing a metallic pigment was obtained by molding into a sheet.
Then, using a laminate of a fluororesin-containing layer and an acrylic resin-containing layer [KFC film FT-50Y (trade name), Kureha Chemical Industry Co., Ltd.: thickness about 50 μm], the acrylic resin-containing layer side was obtained as described above. Of the surface of the base material layer and the surface of the base material layer, which are laminated and embossed with a squeezing roll (sheet surface temperature: 170° C., speed: 10 m/min) to form an uneven pattern on the surface. The skin material of Example 1 which is a laminate was obtained.
After that, Rezaroid (registered trademark) LV-597SP gloss (trade name: manufactured by Dainichiseika Kogyo Co., Ltd.), which is a urethane-based paint, is gravure coated on the surface base material layer side of the surface material and dried by hot air to a thickness. A 3 μm primer layer was formed.

(Preparation of resin molding substrate)
100 parts by mass of an acrylic resin (manufactured by Mitsubishi Rayon Co., Ltd.) and 5 parts by mass of a processing aid (metabrene: manufactured by Mitsubishi Rayon Co., Ltd.) were used to form an acrylic film having a thickness of 300 μm by a calendering method, and a resin It was used as a molding substrate.
E-295NT (product name, manufactured by Dainichiseika Kogyo Co., Ltd.), which is a urethane-based adhesive, is applied to the surface of the obtained resin-molded substrate, and dried with hot air to form an adhesive layer having a thickness of 40 μm. did.

The adhesive layer formed on the surface of the resin molding substrate and the primer layer formed on the surface material obtained as described above were brought into close contact with each other and molded by TOM molding at 150° C. to obtain a preform. On the surface of the preform, a design having a three-dimensional effect due to the unevenness of the surface of the skin material and having a gold metallic hue was observed.

(Formation of transparent resin layer)
An ultraviolet-curable resin composition (UA-122P: product name, manufactured by Shin-Nakamura Chemical Co., Ltd.) containing a urethane acrylate, an acrylic monomer, and a radical-type photopolymerization initiator on the surface of the preform on the skin side. A solution containing methyl isobutyl ketone as a solvent and having a solid content concentration of 70 mass% was applied by a direct reverse coater and dried at 100° C. for 1 minute to form an ultraviolet curable resin composition layer.
The ultraviolet ray curable resin composition layer is irradiated with ultraviolet rays by a metal halide lamp (irradiation condition: 80 W/cm, conveying speed 20 m/min) to cure the ultraviolet ray curable resin composition layer, and the transparent resin is applied to the surface of the preform. A synthetic resin molded body of Example 1 having a layer was obtained.

[Evaluation of synthetic resin molding]
(Evaluation of appearance)
When the synthetic resin molded body of Example 1 was visually observed, a design having a smooth and mirror-like surface, having a three-dimensional effect due to the unevenness of the surface of the skin material, and having a gold metallic hue was observed.
(Evaluation of scratch resistance)
When the hardness of the surface of the synthetic resin molded body of Example 1 was measured in accordance with the JIS K-5400 (1990) pencil scratching test, it was found that the pencil hardness was H and that it had sufficient scratch resistance.

<Comparative Example 1>
A synthetic resin molded article of Comparative Example 1 was obtained in the same manner as in Example 1 except that the metallic pigment was not added when the composition for forming a skin base material layer was prepared.
When the appearance was evaluated in the same manner as in Example 1, the surface was smooth and mirror-like, but the unevenness of the skin material was not visible, and a three-dimensional design could not be obtained.
When the scratch resistance was evaluated, the pencil hardness was H as in Example 1, and the surface scratch resistance was good.

10 Synthetic resin molding 12 Resin molding base material 14 Skin material for resin molding (skin material)
16 Adhesive Layer 18 Primer Layer 20 Skin Base Material Layer 22 Skin Layer 24 Transparent Resin Layer

Claims (3)

A step of forming a skin layer containing a synthetic resin and having irregularities on the surface,
For the resin molded body, a skin base material layer containing a synthetic resin, a metallic pigment, and a coloring agent other than the metallic pigment is formed on the surface of the skin layer opposite to the side having the irregularities. A step of obtaining a skin material,
A step of disposing the skin material for a resin molded body on the surface of a resin molded base material so that the resin molded base material and the skin base material layer are in contact with each other, and heat-molding to obtain a preformed body; and And a step of forming a transparent resin layer by applying a transparent resin on the surface of the skin material for the resin molded body arranged in the preformed body,
A method for producing a synthetic resin molded body, which comprises a resin molded substrate, a skin substrate layer, a skin layer, and a transparent resin layer in this order. The method for producing a synthetic resin molded body according to claim 1 , further comprising a step of forming an adhesive layer between the resin molded substrate and the skin substrate layer. Forming a transparent resin layer by applying the transparent resin of claim 1 or claim 2 comprising the step of applying said resin molded body skin material transparent resin layer forming composition on the surface of Method for manufacturing synthetic resin molded body.