WO2010001767A1 - Process for producing laser-etched article and laser-etched article - Google Patents

Abstract

The technique for forming a laser-etched article by coating a surface of a molded resin with a coating material differing in color from the resin of the resin composition to form a coating film and irradiating part of the coating film with laser light to remove the irradiated part of the coating film has a drawback that the resultant article has a recess at the boundary between the area where the coating film has been removed and the area where the coating film remains.  As a result, fouling substances including dirt from fingers accumulate in the recess to impair the color of the molded resin as the base and make the displayed image illegible.  There also has been a problem that the difference in level at this boundary triggers the peeling of the coating film around the recess.  In order to eliminate these problems, a process is provided in which use is made of a decorative molded article which comprises: a molded resin having such a property that areas irradiated with laser light foam; and a decorative layer formed on the molded resin.  Part of the decorative molded article is irradiated with laser light from the side having the decorative layer on the surface to thereby remove the decorative layer in the region irradiated with laser light.  The irradiation with laser light is further continued to foam the molded-resin surface in the region and thereby form a foam layer.

Description

Laser etching product manufacturing method and laser etching product

The present invention relates to a method for manufacturing a laser-etched product that imparts clear characters, symbols, and the like to a surface of a molded product such as a display panel such as a home appliance, an acoustic device, or an automobile indicator, or a key button.

As shown in FIG. 6, conventionally, a coating film 102 is formed on the surface of the resin molded article 101 by applying a paint different from the resin color of the resin composition, and a part of the coating film 102 is irradiated with laser light. There is a technique in which the film 102 is removed to form a laser-etched product 103, and the underlying color, pattern, characters, etc. visible from the irradiated area (the part from which the coating film has been removed). The laser-etched product 103 is used for, for example, an in-vehicle audio panel, a key button, and the like.

JP-A-7-216116

However, in the above method, a step corresponding to the thickness of the coating film 102 occurs at the boundary between the portion where the coating film 102 is removed and the portion where the coating film 102 is not removed. That is, a concave portion corresponding to the thickness of the removed coating film 102 is generated. As a result, when the formed key button is used for a long period of time, dirt such as finger dirt accumulates in the concave portion, and the color of the underlying resin molded product 101 is impaired, making it difficult to see the display. In addition, there is a problem that the coating film around the recess is peeled off due to the step.

The present invention solves the above problem by preventing the formation of the recess even by laser beam irradiation, thereby maintaining a clear display of the part where the coating film is removed, and a method for producing a laser-etched product in which the surroundings are not peeled off The purpose is to provide.

In order to achieve the above object, the present invention has the following features.

In the method for producing a laser-etched product of the present invention, a decorative layer is laminated on the surface of a decorative product in which a decorative layer is laminated on a resin layer in which a region irradiated with laser light is irradiated by laser light irradiation. By irradiating a part of the decorative product with laser light from the side, the decorative layer in the region irradiated with the laser light is removed, and the laser light irradiation is continued to foam the surface of the resin layer in that region Thus, a foamed layer is formed. Examples of the resin layer include resin molded products.

In the above invention, the decorative layer laminated on the resin layer may be formed by transfer of a transfer film.

In the above invention, the surface of the foamed layer may be flush with the surface of the decorative layer. However, the height difference of about ± 0.3 mm from the surface of the decorative layer is within the same plane.

In the above invention, the surface of the foam layer may be raised higher than the surface of the decorative layer.

The laser-etched product of the present invention is characterized by being formed by any one of the above-described methods for producing a laser-etched product.

According to the method for producing a laser-etched product of the present invention, the surface of the resin layer is foamed after the laser beam is irradiated and the decorative layer is removed, or at the same time when the laser beam is irradiated and the decorative layer is removed. . Since the resin layer expands due to the foaming, the recessed portion formed in the portion where the decorative layer is removed can be filled. Since the above-mentioned concave portion does not occur in the region irradiated with the laser beam, the region is not soiled and a clear display can be maintained. In addition, the decorative layer is not peeled off as a result of the stepped portion of the portion where the decorative layer is removed and the portion where the decorative layer is not removed.

Further, according to the above invention, the decorative layer can be formed of a transfer layer of a transfer film. Therefore, a decoration layer can be formed simply.

Further, according to the above invention, the surface of the foam layer can be flush with the surface of the decorative layer. Therefore, a laser-etched product having a smooth surface can be obtained.

Further, according to the above invention, the surface of the foam layer can be raised higher than the surface of the decorative layer. Thus, the foam layer can be used as braille for blind people.

It is sectional drawing which shows the manufacturing method of the laser etching goods of this invention. It is sectional drawing of the transfer film for providing a decoration layer on the surface of a resin molded product. It is sectional drawing which shows the method of providing a decoration layer on the surface of a resin molded product by the transfer method. It is sectional drawing which shows the method of providing a decoration layer on the surface of a resin molded product by the shaping | molding simultaneous transfer method. It is sectional drawing of an example of the laser etching goods formed by the manufacturing method of the laser etching goods of this invention. It is sectional drawing of the laser etching goods manufactured by the manufacturing method of the conventional laser etching goods.

Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing a method for producing a laser-etched product of the present invention. FIG. 2 is a cross-sectional view of a transfer film for providing a decorative layer on the surface of a resin molded product. FIG. 3 is a cross-sectional view showing a method of providing a decorative layer on the surface of a resin molded product by a transfer method. FIG. 4 is a cross-sectional view showing a method of providing a decorative layer on the surface of a resin molded product by a simultaneous molding transfer method. FIG. 5 is a cross-sectional view of an example of a laser-etched product formed by the laser-etched product manufacturing method of the present invention. FIG. 6 is a cross-sectional view of a laser-etched product manufactured by a conventional method for manufacturing a laser-etched product.

The resin molded product 1 which is an example of a resin layer is a resin composition which causes foaming by laser light irradiation. The resin molded product 1 may contain, in addition to the resin composition, an additive that causes foaming of the resin composition by laser light and / or an additive that promotes foaming. Examples of the resin composition include polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyvinyl chloride resins, poly (meth) acrylate resins, acrylic resins, polyacetal resins, polyester resins such as polyethylene terephthalate and polybutylene terephthalate. Further, known thermoplastic resins such as polyamide resin, polycarbonate resin, polyphenylene sulfide resin, polyimide resin and the like and resins obtained by modifying these can be used. These resins can be used alone or in admixture of two or more. The additive to the resin composition includes (1) an additive A that causes the additive itself to change and foam the resin composition, and / or (2) the additive melts and heats the resin composition. Additive B that decomposes and induces foaming can be used. Examples of the additive A include a foaming agent, a glass balloon, a shirasu balloon, a transition metal compound such as iron oxide, and a cobalt oxide. Examples of the additive B include carbon black and a transition metal compound. The contents of these additives A and B are not particularly limited, but may be added in the range of 0.1 to 20 parts with respect to 100 parts of the resin composition from the viewpoint of the strength of the resin molded product. preferable. More preferably, it is 0.5 to 10 parts. In the present invention, it is particularly inexpensive to blend 0.01 to 1.0% by weight of carbon black, and an excellent foaming effect can be obtained. If the blending amount of the carbon black is less than 0.01% by weight, sufficient foaming cannot be performed. Conversely, if it exceeds 1.0% by weight, the surface of the resin molded product 1 is not foamed by laser irradiation. Since it will be shaved and a hollow will be produced, it will become difficult to form the relief with good contrast. More preferably, it is 0.05 to 0.5% by weight.

In addition, a known additive or the like can be added as necessary within a range that does not significantly impair the foaming effect by laser irradiation. For example, inorganic fillers, antioxidants, heat stabilizers, ultraviolet absorbers, stabilizers such as light stabilizers, antistatic agents, flame retardants, flame retardant aids, colorants such as dyes and pigments, lubricants, plastics An agent, a release agent, a surfactant, a crystallization accelerator, a crystal nucleating agent, and the like can be blended. Examples of the pigment include inorganic pigments, organic pigments, metallic pigments, pearl pigments, and fluorescent pigments. Examples of organic pigments include azo pigments, phthalocyanine pigments, anthraquinone pigments, perinone pigments, and quinacridone pigments.

The shape of the inorganic filler is not particularly limited, and may be any of fibrous, powdery, plate-like and the like. Preferably, granular and plate-like inorganic fillers are used. The color of the inorganic filler is preferably white or light, and for example, talc, calcium carbonate, titanium oxide and the like can be used. When these inorganic fillers are further blended, the addition amount is preferably 1 to 50% by weight. More preferably, it is 2 to 30% by weight.

In any case, it is preferable that the resin molded product 1 is colored in order to absorb the laser energy without transmitting.

The decorative molded product 6 is formed by laminating the decorative layer 2 on the resin molded product 1.

As the decorative layer 2 formed on the surface of the resin molded product 1, a paint may be directly formed on the surface of the resin molded product 1. As a coating material, a resin such as polyvinyl resin, polyamide resin, polyester resin, acrylic resin, polyurethane resin, polyvinyl acetal resin, polyester urethane resin, cellulose ester resin, alkyd resin is used as a binder. Colored inks containing color pigments or dyes as colorants may be used. The decorative layer 2 may be formed by a gravure printing method, spray coating, or the like. The decorative layer 2 is selected from those having good adhesion to the resin molded product 1. When the resin molded product 1 and the decorative layer 2 are difficult to adhere to each other, an adhesive layer that assists mutual bonding, such as an anchor layer (not shown), may be provided. In this case, it is necessary to remove the anchor layer in the portion irradiated with the laser beam described later, but it is easily removed by the laser beam irradiation.

As shown in FIG. 2, a transfer sheet 11 may be used to form the decorative layer 2. The transfer sheet 11 will be described. The transfer sheet 11 is obtained by forming at least a transfer layer 16 including a pattern layer 14 on a base sheet 12. The transfer film 11 is fused to the resin molded product 1 by a transfer method or a simultaneous molding transfer method described later, the base sheet 12 of the transfer film 11 is peeled off, and the transfer layer 16 of the transfer film 11 is used as a decorative layer 2 The decorative molded product 6 transferred to the surface of the molded product 1 is formed.

As the base sheet 12, polyester resin, polypropylene resin, vinyl chloride resin, polyethylene resin, polyethylene terephthalate resin, polycarbonate resin, nylon resin, vinylon resin, acetate resin, polyethylene resin, polyamide resin, polyacrylic resin, Plastic sheets such as polyvinyl chloride resins can be used. The thickness of the base sheet 12 is preferably 10 to 100 μm. More preferably, it is 20 to 60 μm. It is preferable to use a base sheet 12 having peelability by itself. In order to further stabilize the peelability, a release layer (not shown) may be formed on the surface of the base sheet 12. The release layer is a layer that is removed together with the base sheet 12 after the transfer process. As a material for the release layer, a curable resin such as a silicone resin, a melamine resin, an alkyd resin, or an epoxy resin may be used. As a method for forming the release layer, there are a coating method such as a roll coating method and a spray coating method, a printing method such as a gravure printing method and a screen printing method.

Further, in order to more surely separate the transfer layer 16 from the base sheet 12 or the release layer, a release layer 13 may be formed as necessary. The release layer 13 is a layer that peels off from the base sheet 12 or the release layer and becomes the outermost surface of the transfer layer 16 that is a transfer object when the base sheet 12 is peeled after transfer or after simultaneous molding transfer. The release layer 13 may be made of acrylic resin, polyester resin, polyvinyl chloride resin, cellulose resin, rubber resin, polyurethane resin, polyvinyl acetate resin, or vinyl chloride-vinyl acetate copolymer. Copolymers such as system resins and ethylene-vinyl acetate copolymer resins may be used. When the release layer 13 requires hardness, a photo-curing resin such as an ultraviolet curable resin, a radiation curable resin such as an electron beam curable resin, or a thermosetting resin may be selected and used. Examples of the method for forming the release layer 13 include a coating method such as a gravure coating method, a roll coating method, and a comma coating method, and a printing method such as a gravure printing method and a screen printing method.

As a material for the pattern layer 14, a resin such as a polyvinyl resin, a polyamide resin, a polyester resin, an acrylic resin, a polyurethane resin, a polyvinyl acetal resin, a polyester urethane resin, a cellulose ester resin, or an alkyd resin is used as a binder. And a color ink containing an appropriate color pigment or dye as a colorant may be used. As a method for forming the pattern layer 14, a normal printing method such as a gravure printing method, a screen printing method, or an offset printing method may be used. The thickness of the pattern layer 14 is preferably 1 to 30 μm. More preferably, it is 2 to 20 μm. The pattern layer 14 is not limited to colored ink, and may form a metal vapor deposition layer or the like to express a design with metallic luster. Aluminum, chromium, copper, tin, or the like is used as the material for the metal deposition layer. The metal vapor deposition layer may be formed by using a vacuum vapor deposition method, a sputtering method, an ion plating method, or the like.

Further, the adhesive layer 15 may be formed as necessary. The adhesive layer 15 is a layer for adhering the transfer material to the resin molded product 1 by a transfer method or a simultaneous molding transfer method. When the material of the resin molded product 1 is a polyacrylic resin, a polyacrylic resin may be used as the material of the adhesive layer 15. In addition, when the material of the resin molded product 1 is polyphenylene oxide / polystyrene resin, polycarbonate resin, styrene copolymer resin, or polystyrene blend resin, polyacrylic resin or polystyrene resin having affinity with these resins Polyamide resin or the like may be used as the material for the adhesive layer 15. As a method for forming the adhesive layer 15, it is preferable to use a gravure coating method, a roll coating method, a comma coating method, a gravure printing method, a screen printing method, or the like. The dry film thickness of the adhesive layer 15 is generally 1 to 5 μm.

The transfer process of transferring the transfer layer 16 as the decorative layer 2 from the transfer sheet 11 onto the resin molded product 1 by the transfer method is performed as follows. First, the adhesive layer 15 side of the transfer sheet 11 is brought into close contact with the surface of the resin molded product 1. Next, as shown in FIG. 3, using a transfer machine such as a roll transfer machine or an up-down transfer machine equipped with a heat-resistant rubber-like elastic body 21 such as silicon rubber, the temperature is about 80 to 260 ° C., and the pressure is about 500 to 2000 Pa. Heat and pressure are applied from the base sheet 12 side of the transfer sheet 11 through the heat-resistant rubber-like elastic body 21 set to the above conditions. By doing so, the adhesive layer 15 adheres to the surface of the resin molded product 1. Finally, when the base sheet 12 is peeled off after cooling, the transfer layer 16 is transferred to the surface of the resin molded product 1 as the decorative layer 2 and the transfer process is completed.

The transfer step of transferring the transfer layer 16 as the decorative layer 2 from the transfer sheet 11 onto the resin molded product 1 by the simultaneous molding transfer method is performed as follows. First, as shown in FIG. 4A, the transfer sheet 11 is fed into a molding die 31 composed of a movable mold and a fixed mold. At that time, the single transfer sheet 11 may be fed one by one, or a necessary portion of the long transfer sheet 11 may be intermittently fed. When the long transfer sheet 11 is used, it is preferable to use a feeding device having a positioning mechanism so that the registers of the transfer sheet 11 and the molding die 31 coincide with each other. Further, when the transfer sheet 11 is intermittently fed, the transfer sheet 11 may be fixed by a movable mold and a fixed mold after the position of the transfer sheet 11 is detected by a sensor. After the molding die 31 is closed, the molding resin 32 is injected and filled into the die from the gate 33 to form the resin molded product 1, and at the same time, the transfer sheet 11 is adhered to the surface of the resin molded product 1. After cooling the resin molded product 1, the molding die 31 is opened and the resin molded product 1 is taken out. Finally, when the base sheet 12 is peeled off, as shown in FIG. 4B, a decorative molded product 6 in which the transfer layer 16 is transferred as a decorative layer 2 to the surface of the resin molded product 1 is formed. Is completed.

As a laser device for performing laser etching by irradiating a part of the decorative molded product 6 in which the decorative layer 2 is laminated on the surface of the resin molded product 1 and performing laser etching, for example, a carbon dioxide laser device, ruby Examples thereof include a laser device, a semiconductor laser device, an argon laser device, an excimer laser device, a YAG laser device, and a VYO ₄ laser device. Among them, semiconductor lasers such as an Nd: YAG laser with a wavelength of 1064 nm and an AlGaAs laser with 824 nm are common and easy to use.

As shown to Fig.1 (a), with respect to the decoration molded product 6 by which the decoration layer 2 was laminated | stacked on the surface of the resin molded product 1, the decoration molded product 6 from the side by which the decoration layer 2 was laminated | stacked on the surface. A part of the laser beam 3 is irradiated with the laser beam 3. As a method of irradiating the laser beam 3 to form an arbitrary character or figure, for example, a method in which the laser beam 3 is fixed and the decorative molded product 6 is moved back and forth or left and right, or a decorative molded product 6 is fixed and laser is used. A method of moving the light 3 back and forth and right and left can be used. As shown in FIG. 1B, when the laser beam 3 is irradiated, the decorative layer 2 in the region irradiated with the laser beam 3 is removed by being burned off by the energy of the laser beam 3, and the decorative layer is removed. Immediately after being applied, or when the decorative layer is removed by irradiation with laser light, the irradiated portion of the resin molded product 1 is softened and dissolved. At this stage, a concave portion corresponding to the thickness of the decorative layer 2 is generated in the irradiation region. Further, when the laser beam irradiation is continued, the outermost surface portion of the irradiated portion of the resin molded product 1 is burned out, but the low molecular weight resin contained in the resin contained in the dissolved resin inside the irradiated portion of the resin molded product 1 Volatile components such as components, decomposition products, additives and the like are heated to a high temperature to be vaporized or foamed, so that the irradiated portion of the resin molded product 1 rises and becomes a foamed layer 4. As shown in FIG. 1C, by adjusting the irradiation time, irradiation intensity, etc. of the laser beam 3, the top surface positions of the decorative layer 2 and the foam layer 4 are made substantially the same, and there is a step between them. It can be prevented from occurring. Since the surface of the foamed layer 4 does not accumulate dirt, the color of the foamed layer 4 is not impaired and the display can be maintained clearly. Moreover, since there is no level | step difference between the decoration layer 2 and the foaming layer 4, the decoration layer 2 is not peeled off by the boundary part of both. When irradiation with the laser beam 3 is stopped in this state, the foamed layer 4 is cooled and solidified in a state containing a large number of bubbles inside, and a laser-etched product 5 is formed. This foam layer 4 may be different from the color of the original resin molded product 1, and many of them are irregularly reflected in light and appear milky white. Actually, the steps from the irradiation of the laser beam 3 to the formation of the foamed layer 4 occur in a very short time.

Further, by adjusting the irradiation time and intensity of the laser beam 3, the surface of the foam layer 4 can be raised higher than the surface of the decorative layer 2 (see FIG. 5). In this case, the foam layer 4 can be used as Braille for a blind person. In order to make it easier to read Braille by touching the finger, the height of the foam layer 4 from the surface of the decorative layer 2 is about 0.4 to 0.7 mm (preferably about 0.5 to 0.6 mm). Is preferred. If the laser beam 3 is irradiated too much, the foam layer 4 is burned out, and a recess is formed in the laser-etched product 5.

A polyethylene terephthalate film having a thickness of 38 μm was used as a base sheet 12, and then a release layer 13, a pattern layer 14, and an adhesive layer 15 were sequentially formed by a gravure printing method to obtain a transfer sheet 11. The release layer 13 and the pattern layer 14 were each formed using an ink made of an acrylic resin. The adhesive layer 15 was formed using an ink made of a vinyl chloride-vinyl acetate copolymer resin.

Next, the transfer sheet 11 thus obtained is placed between the molding dies 31 and clamped, then the molding resin 32 is injected and integrated, and after opening the mold, the base sheet 12 of the transfer sheet 11 is formed. The decorative molded product 6 in which the transfer layer 16 was transferred as the decorative layer 2 onto the resin molded product 1 was obtained.

Next, using a Nd: YAG laser device having a wavelength of 1064 nm, a part of the decorative molded product 6 is irradiated with the laser beam 3 to remove the decorative layer 2 in the region irradiated with the laser beam 3, and Laser in which the surface of the foamed layer 4 is substantially flush with the surface of the decorative layer 2 by forming the foamed layer 4 by continuously irradiating the laser beam 3 and foaming the surface of the resin molded product 1 in the irradiated region. Etched product 5 was obtained.

The laser-etched product 5 obtained in this way was able to maintain a clear display because the surface of the foamed layer 4 that was irradiated with the laser beam 3 did not accumulate dirt. Moreover, the decoration layer 2 was not peeled off at the boundary between the decoration layer 2 and the foam layer 4 as a trigger.

DESCRIPTION OF SYMBOLS 1 Resin molding 2 Decorating layer 3 Laser beam 4 Foaming layer 5 Laser etching product 6 Decorating and molding product 11 Transfer sheet 12 Base sheet 13 Peeling layer 14 Picture layer 15 Adhesive layer 16 Transfer layer 21 Heat resistant rubber-like elastic body 31 For molding Mold 32 Molded resin 33 Gate 101 Resin molded product 102 Paint film 103 Laser etched product

Claims (5)

Laser light is irradiated to a part of the decorative product from the side where the decorative layer is laminated on the surface of the decorative product on which the decorative layer is laminated on the resin layer in which the region irradiated with laser light is foamed Removing the decorative layer in the region irradiated with laser light, and further forming the foamed layer by continuing the laser light irradiation to foam the surface of the resin layer in the region. To manufacture laser-etched products. The method for producing a laser-etched product according to claim 1, wherein the decorative layer laminated on the resin layer is formed by transferring a transfer layer of a transfer film. The method for producing a laser-etched product according to claim 1, wherein the surface of the foam layer is flush with the surface of the decorative layer. The method for producing a laser-etched product according to claim 1, wherein the surface of the foam layer is raised higher than the surface of the decorative layer. A laser-etched product formed by the method for producing a laser-etched product according to any one of claims 1 to 4.

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