JP3419886B2 - Transfer sheet - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum press transfer to an outer surface of a three-dimensionally shaped substrate (transfer member) such as a cabinet of a light electric appliance, an interior member of an automobile, and the like. The present invention relates to a transfer sheet used for painting and decorating by a method. 2. Description of the Related Art Generally, this type of transfer sheet has a structure in which a release layer, a decorative layer, an adhesive layer, and the like are laminated on a base material sheet, and is roll-transferred onto the surface of a formed transfer receiving body. Alternatively, there is an after-transfer sheet used for decorating by up-down transfer, and an in-mold transfer sheet used for transferring simultaneously with molding of a transfer-receiving body. [0005] The former transfer sheet described in the prior art has the following problems. The decorative surface is limited to a two-dimensional plane or a cylindrical side surface, and cannot be transferred and painted on a three-dimensional substrate (transfer member) having an aperture or the like. When the transfer sheet is stretch-formed at ordinary temperature, design defects such as peeling of the transfer layer from the base sheet and breakage or collapse of the transfer layer occur. On the other hand, the latter transfer sheet has the following problems. It is used for a system that decorates at the same time as injection molding, resulting in poor productivity and high cost. Since the molded article cannot be decorated, it cannot be re-decorated and the like, and the yield is poor. The size of the molded article is limited. Unless the transfer sheet is heated and softened as a pre-transfer operation, cracks and cracks occur in the transfer layer, making it impossible to decorate a deep-drawn base (transfer member). The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to prevent the transfer layer from peeling off from the substrate sheet even when stretched at room temperature, and Another object of the present invention is to provide a transfer sheet in which cracks, cracks and the like are prevented from being disturbed. SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for transferring a transfer sheet to a transfer target at room temperature.
Covering along its uneven shape by vacuum molding or vacuum pressure molding
After pressing and heating with a heating rubber, the adhesiveness of the transfer layer
And the transfer layer is adhered to the transfer object.
Transfer used for the transfer method for decorating curved surfaces of three-dimensional molded products
A sheet having a layer structure in which at least a decorative layer is laminated on a base sheet, and having a elongation at break of 5 to 150% at room temperature as the decorative layer; It is characterized by using a material that follows the elongation of the layer. In the transfer sheet of the present invention, the transfer layer (the layer separated from the base sheet and transferred to the object to be transferred) comprises at least a decorative layer, and if necessary, a release layer and an adhesive layer may be provided. Will be added. Therefore, as a layer configuration of the transfer layer,
Base sheet / decorative layer, base sheet / release layer / decorative layer, base sheet / decorative layer / adhesive layer, or base sheet / release layer / decorative layer / adhesive layer. [0008] The material of the base sheet may in principle be any material having a releasability from the transfer layer used in this type of transfer sheet.
m is preferred, and more preferably 19 to 50 μm. Specific examples of the material of the base sheet, polyethylene terephthalate, polybutylene terephthalate, polyester-based resin such as polyethylene terephthalate-isophthalate copolymer, polyethylene, polypropylene, polyolefin-based resin such as polymethylpentene,
Polyethylene fluoride resin such as polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, ethylene / tetrafluoroethylene copolymer, nylon-6, nylon-6,6
Polyamide resin, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, vinyl resin such as polyvinyl alcohol, cellulose triacetate, cellulosic resin such as cellophane, polymethyl methacrylate Acrylic resins such as polyethyl methacrylate, polybutyl acrylate, etc., and synthetic resins such as impact-resistant polystyrene, polycarbonate, polyarylate, and polyimide are included. The material is not particularly limited as long as the material can be stretched following. The base sheet is kneaded with a matting agent or the like, or is entirely or partially glossed by printing, coating, or the like using an ink containing a matting agent that has a release property from the transfer layer and adheres tightly to the base sheet. It is also possible to change. On the release surface of the base sheet, a release layer serving as a surface layer of a transfer layer to be transferred to a substrate (transfer member) is formed as necessary. That is, the release layer serves as a surface layer of the transfer layer remaining on the substrate (transferred object) side when the base sheet is separated from the transfer sheet after the transfer step, and the transfer layer is applied to the base sheet before transfer. After transfer, it facilitates peeling between the base sheet and the transfer layer after transfer, and further serves to protect the transferred decorative layer. This release layer,
For example, polymethyl methacrylate, acrylic resin such as polybutyl methacrylate, polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, unsaturated polyester, chloride rubber, resin such as cyclized rubber, and further, such as a mixed resin thereof The thickness is usually about 1.0 to 4.0 μm, preferably about 1.5 to 3.0 μm. The decorative layer is to add design characteristics to the substrate (transferred object) by transferring the transfer layer, and each of a pattern layer or a solid layer provided with a picture, a pattern, or the like is used alone or in combination with two layers. It is composed of the above. This decorative layer is formed by printing or applying an ink obtained by adding a coloring agent such as a dye or a pigment to a resin binder. In the present invention, the decorative layer is formed by peeling of the transfer layer from the base sheet or cracking or cracking of the transfer layer when the transfer sheet is three-dimensionally formed on a substrate (transfer object) at room temperature by a vacuum press method. They have found that it depends on the stretchability of the resin (specifically, evaluated by elongation at break (%)), and have developed the transfer sheet of the present invention. The decorative layer extends in accordance with local stretching that occurs when vacuum forming is performed at room temperature. More specifically, when a three-dimensional uneven shape of a normal molded product is targeted, the decorative layer is formed at room temperature. Any material having an elongation at break of 5 to 150% can be used. If the elongation at break is less than 5%, transfer can be performed only to almost flat molded products. Conversely, if it exceeds 150%, foil burrs become remarkable during transfer and removal thereof becomes difficult. Here, the term “foil burr” means that the film is not sharply cut at a boundary between a portion where the transfer layer is transferred and a portion where the transfer layer is not transferred, and protrudes into a so-called “burr”. As the binder of this decorative layer, the elongation at break is 5 to 150.
% Or more is selected. The resin that can be selected depends on the stretching ratio at the time of molding. For example, polyurethane (a variety of resins can be used, but thermoplastic polyurethane or urethane elastomer is particularly preferable), urethane acrylate, acrylic polyol, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, etc. And vinylidene chloride-vinyl chloride copolymer, acrylonitrile-vinyl chloride copolymer, rubber and the like. Among these, a mixture of polyurethane and a vinyl chloride / vinyl acetate copolymer is preferred in terms of stretchability and prevention of foil burrs. The decorative layer uses these resins as vehicles, titanium white, carbon black, quinacridone, azo pigments, isoindolinone,
It is formed of a layer provided with coloring or glittering properties in which calcium carbonate, silica, barium sulfate, aluminum foil powder, titanium dioxide-coated mica foil powder and the like are dispersed. The decorative layer formed by adding a coloring agent or the like to the resin binder may have an elongation at break of 5 to 150%. By adding an inorganic extender such as calcium carbonate, silica or barium sulfate among the above pigments, foil burr can be reduced. However, if it is added too much, the elongation at break decreases. An adhesive layer is formed on the decorative layer as required. This adhesive layer is, for example, an acrylic resin,
It is formed of a hot melt resin such as an acrylic / styrene copolymer resin, a vinyl chloride / vinyl acetate copolymer resin, a thermoplastic polyurethane, an ionomer, a chloride rubber, a cyclized rubber, and a chlorinated polypropylene. It is not necessary to form an adhesive layer on the transfer sheet when an adhesive layer is formed in advance on the surface of the substrate as the object to be transferred or when the decorative layer itself has heat-sensitive adhesive properties. Further, when the surface of the substrate as the transfer object is smooth or the like, the particle size is 0.5 to 5%.
A matting agent composed of inorganic fine particles such as silica, calcium carbonate, barium sulfate, kaolinite, talc, and alumina, or thermosetting resin fine particles such as a phenol resin, an epoxy resin, and a melamine resin, of about 1 μm, and more preferably 1 to 3 μm. To form the fine irregularities on the surface of the adhesive layer, it is possible to improve the slip property between the transfer layer and the substrate before the adhesive layer is heated and activated, and to form the fine irregularities on the surface of the adhesive layer. The good flow of the air sucked through the gap with the surface of the transfer body prevents the formation of air pockets between the transfer layer and the substrate during vacuum forming, and further prevents the formation of wrinkles during transfer. From this viewpoint, it is preferable that the fine irregularities on the surface of the adhesive layer, that is, the surface roughness is 0.4 μm or more as a center line average roughness (Ra) according to JIS-B-0601. If only fine irregularities are formed on the surface of the adhesive layer, a matting agent is not added to the adhesive layer, and the surface of the adhesive layer is embossed with fine irregularities by a known method such as hot pressing. Is also good. However, in that case, the minute irregularities are likely to be reduced or eliminated depending on the conditions of the temperature and the pressure during storage of the transfer sheet. Therefore, in order to avoid this, it is preferable to add a matting agent such as inorganic fine particles or thermosetting resin fine particles which are hardly deformed as described above. Each of the above resin layers in the transfer sheet can be formed by, for example, coating means such as gravure coating or roll coating, or printing means such as gravure printing or screen printing. The transfer sheet of the present invention is formed by coating the transfer object at room temperature (about 10 to 30 ° C.) along the concave and convex shape by vacuum forming or vacuum pressure forming, and then forming rubber. The transfer is performed according to a known vacuum press transfer method (for example, see Japanese Patent Application Laid-Open No. 5-131545) in which the transfer layer is developed to have an adhesive property by being pressed and heated to adhere the transfer layer to the transfer target. That is, the transfer sheet is disposed so that the surface of the base, which is the object to be transferred, and the opposite side (transfer layer side) of the base sheet in the transfer sheet are opposed to each other, and the transfer sheet is stretch-formed by vacuum forming at room temperature or the like to form the base. After being aligned, the three-dimensional surface of the substrate having the three-dimensional shape is favorably decorated by being pressed by the molding rubber from the base material sheet side and heated by the heat of the molding rubber. In this case, since the transfer layer is formed on the substrate surface in a state where the adhesive force has not yet been developed (activated) at room temperature, even if there are wrinkles, lumps, air pockets, etc. at the moment when the transfer layer adheres to the substrate surface. The transfer sheet slips and moves on the substrate surface to remove them and does not cause cracks or cracks due to elongation of the transfer layer. An embodiment of the present invention will be described below with reference to the drawings. (Example) A transfer sheet S having a laminated structure shown in FIG. 1 was produced by the following procedure. First, the thickness 2 with corona treatment on one side
A matting polyester layer (Lumirror X455, manufactured by Toray Co., Ltd.) having a thickness of 6 μm was used as the base sheet 1, and a mat ink layer 2 remaining on the base sheet side after the transfer was formed on the corona-treated side of the base sheet 1. . Specifically, a mixture of a mat ink composed of aminoalkyd / butylated melamine / silica powder (weight ratio: 70/15/5) and a methanol solution of hydrochloric acid (20%) at a ratio of 100: 5 is subjected to gravure printing. After printing in a desired pattern, a heat treatment was performed at 100 ° C. for 5 seconds. Next, a release varnish (acrylic resin, having a glass transition point of 105 ° C.) is applied on the entire surface of the matt ink layer 2 to form a release layer 3 having a thickness of 2.5 μm. The decorative layer 4 was formed on 3. Specifically, the colored pattern layer 4a is formed in a desired pattern using a flexible ink in which the binder is a polyurethane / vinyl chloride / vinyl acetate copolymer (weight ratio: 50/50), and the colored pattern layer 4a is formed thereon. Solid layer 4 with different hue
b was formed with the same type of flexible ink at a thickness of 2.5 μm, and solid layers 4 c and 4 d with a thickness of 3 μm were formed with the same type of white flexible ink. Subsequently, an adhesive layer 5 was formed on the decorative layer 4. Specifically, a mixture of silica powder having a particle size of 2.5 μm as a matting agent at a ratio of 5% by weight and a thickness of 4 μm was applied to an acrylic resin binder. The surface roughness of the adhesive layer 5 is JIS-B-0601.
Was 0.45 μm in center line average roughness. Using the transfer sheet S thus prepared, an air conditioner panel with a lattice having a three-dimensional curved surface formed of a polystyrene resin (the transfer sheet has a maximum elongation of 5% at a portion covered with the transfer sheet). Designed to shape)
Was decorated by a vacuum press transfer method. As a procedure, first, the adhesive layer 5 of the transfer sheet S was disposed so as to face the panel surface, and the transfer sheet S was stretched and formed by vacuum forming at a room temperature of 20 ° C., and was formed along the air conditioner panel. In this state, a silicon molded rubber heated to 170 ° C. from the side of the base sheet 1 was pressed for about 3 seconds to apply heat and pressure, and then the base sheet 1 was peeled off. As a result, the air conditioner panel could be favorably decorated without cracks or cracks in the transfer layer, including the three-dimensional curved surface. Further, there was no foil burr in the lattice of the air conditioner panel. In addition, the decoration surface had a high-grade decoration with a gloss mat effect. (Experiment 1) In the above embodiment, a transfer sheet having the same layer structure was prepared by changing the resin mixing ratio in the binder of the flexible ink for forming the decorative layer 4, and this was used to form an air conditioner panel in the same manner as in the above embodiment. Was decorated. The thickness of the decoration layer 4 is the same as that of the above embodiment. Table 1 shows the results of the evaluation of each of these cases together with the above-described example (shown in C). In Table 1, X is polyurethane, and Y is vinyl chloride.
Represents a vinyl acetate copolymer. [Table 1] As can be seen from the results, the one having an elongation at break of 5 to 150% does not cause cracks in the decorative layer and does not cause transfer failure due to delamination of the transfer layer during transfer. Was. In addition, no or no small amount of foil burrs were generated, and the burrs could be easily removed by wiping the cloth or blowing air. (Experiment 2) In the above embodiment, the adhesive layer 5 was used.
By changing the mixing ratio of the matting agent (silica powder having a particle size of 2.5 μm), a transfer sheet having the same layer configuration (the thickness of the adhesive layer was also the same at 4 μm) was prepared, and the air conditioning panel was similarly decorated did. Table 2 shows the results of the evaluation performed for each of these cases, together with the above examples (shown in H). [Table 2] As can be seen from the results, the surface roughness of the adhesive layer is the center line average roughness (R) according to JIS-B-0601.
In the case of a) having an adhesive layer of 0.4 μm or more, no air trapped or the like was generated even when transferred to any substrate (transferred object). Although there is no particular upper limit for Ra from the viewpoint of air accumulation, if it is too large, the surface of the transfer layer becomes rough. The particle size of the matting agent to be added is preferably in the range of 1 to 3 μm. If it is less than 1 μm, Ra of 0.4 μm or more cannot be produced at all, or even if it can be produced, the added amount becomes too large, and the coating film becomes brittle or loses printability, and conversely, exceeds 3 μm. Then, even if Ra is the same, Rmax (JIS-B-0)
601) tends to be large, and the surface of the transferred transfer layer is roughened. The present invention is configured as described above, and has the following effects. After the transfer sheet is vacuum-formed at room temperature, the transfer layer is heated to develop the adhesiveness of the transfer layer and the transfer is performed, whereby the curved surface of the three-dimensional molded article can be decorated. At this time, wrinkles, bulges, and air pockets of the transfer sheet, which tend to occur, are not generated. Further, cracks and the like due to elongation of the transfer layer do not occur. It is not necessary to heat the transfer sheet as an operation before the transfer, and the inexpensive transfer system utilizing a conventional vacuum press transfer machine can efficiently decorate a three-dimensional molded product with a curved surface. It is possible to decorate a molded three-dimensional molded product with a curved surface, and to perform decoration correction that cannot be performed by an existing three-dimensional transfer system (in-mold molding method), thereby improving the yield. it can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a transfer sheet for explaining an example of the present invention. [Description of Signs] 1 Base sheet 2 Mat ink layer 3 Release layer 4 Decorative layer 4a Pattern layers 4b, 4c, 4d Solid layer 5 Adhesive layer

Claims (1)

(57) [Claims] [Claim 1] A transfer sheet is held at normal temperature against
Covering along its uneven shape by vacuum molding or vacuum pressure molding
After pressing and heating with a heating rubber, the adhesiveness of the transfer layer
And the transfer layer is adhered to the transfer object.
Transfer used for the transfer method for decorating curved surfaces of three-dimensional molded products
A sheet having a layer structure in which at least a decorative layer is laminated on a base material sheet, the decorative layer having an elongation at break of 5 to 150% at normal temperature is used as the base material sheet; A transfer sheet using a material that follows the elongation of a layer.