JP2006289839A - Transfer method for transferring pattern to body to be transferred and transfer sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To transfer a beautiful pattern even to a wide area of a body to be transferred with a three-dimensional curved face by preventing it from getting wrinkled. <P>SOLUTION: The transfer method is composed so as to transfer an ink of a transfer sheet 2 to the body 1 to be transferred by adhering the transfer sheet 2 to the surface of the body 1 to be transferred by reducing the pressure on the rear face side where the transfer sheet 2 faces the body 1 to be transferred lower than that of on the surface side opposite to the rear face side after arranging the transfer sheet 2 on the surface of the body 1 to be transferred. The transfer sheet 2 is composed by providing an ink layer 24 on the surface of a urethane base material sheet 21, which has elongation at rupture of ≥600% and an elastic recovery rate of ≤10%, via a mold release layer 22. A pattern is provided to the ink layer 24 of the transfer sheet 2 with ink dots 24A thermally fused by heating. The pattern is transferred to the body 1 to be transferred while reducing gaps 24B between the dots of the ink dots 24A by fusing and expanding the ink dots 24A by heating the transfer sheet 2 in a state of being adhered on the surface of the body 1 to be transferred. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for transferring a pattern of a transfer sheet onto the surface of a transfer object, and a transfer sheet used in this method, and in particular, automotive parts such as steering wheels, shift knobs, automobile interior materials, etc., or home appliances The present invention relates to a transfer method used for decorating general products with complicated three-dimensional curved surfaces, such as exteriors of Buddhist altars and Buddhist altars, and a transfer sheet used therefor.

  For high-end cars, wooden steering wheels and shift knobs are used. The wooden steering wheel is made of high-quality wood that is processed into a circular shape and a metal core is embedded inside. The steering wheel with this structure decorates the surface with a beautiful grain pattern unique to natural wood. Maple and walnut are used as natural wood. Some of these natural trees have beautiful grain patterns and others do not. Steering wheels manufactured using first-class natural wood, which has a very beautiful grain pattern, and steering wheels manufactured using third-class natural wood, even if the manufacturing process is the same, The commercial value of the product is significantly different. In order to use a third-class natural wood as a first-class steering wheel, a method for displaying a beautiful wood grain pattern with ink on the surface of the natural wood has been proposed.

  As a transfer method for realizing this method, a vacuum forming method in which a wood grain pattern is attached to the steering wheel surface using a transfer sheet and a method in which a pattern is attached by a hydraulic transfer method (see Patent Document 1) are developed. Has been.

  The conventional vacuum forming method uses a vinyl chloride resin, a polyolefin resin, or a polyester resin sheet as a base sheet for a transfer sheet that is heated to a vacuum forming temperature of 60 to 80 ° C. and stretches well along a three-dimensional curved surface. use. For example, when a pattern is transferred to a steering wheel using this transfer sheet, the transfer sheet cannot be adhered to the entire circumference of the circular steering wheel when the pattern is transferred to the steering wheel using this transfer sheet. The pattern can be transferred only to the front side and part of the back side. Furthermore, when the conventional transfer sheet is brought into contact with the steering wheel over a wide area, the back surface of the steering wheel is wrinkled and cannot be transferred to a beautiful pattern. For this reason, the wood grain pattern cannot be transferred without a break to the entire 360 ° circumference of the steering wheel. If the transfer sheet is attached to the steering wheel in a state where wrinkles are formed, the wood grain pattern cannot be attached cleanly at the wrinkles.

  In the water pressure transfer method, ink is floated on the water surface in a wood grain pattern and adhered to the steering wheel surface. This method does not cause deterioration in the quality of the pattern due to wrinkles unlike a transfer film. However, it is extremely difficult to attach a wood grain pattern to the surface of the steering wheel. Also, as with the transfer sheet, a thin-grain wood pattern is attached to the surface of the steering wheel, so there is a screen mesh that cannot be the same as natural wood. For this reason, a high-grade steering wheel cannot be manufactured even by this method. Furthermore, in this method, it is more difficult to stably adhere the wood grain pattern than the transfer film, and it is difficult to transfer the wood grain pattern neatly so as not to peel off. For this reason, there is a drawback that high-quality steering wheels cannot be mass-produced efficiently at low cost.

  Furthermore, the biggest drawback of the water pressure transfer method is that it uses water for the transfer environment, so it cannot be used for materials that dislike water wetting. For example, there is a drawback that when a pattern is hydraulically transferred onto the surface of wood, the wood absorbs moisture and a beautiful pattern cannot be obtained.

The Applicant has developed a method to eliminate these drawbacks. (See Patent Document 2) In this transfer method, ink is supplied to the concave portion of the engraving roller provided with concave portions constituting the pattern on the surface, and the ink supplied to the concave portion of the engraving roller is applied to the surface of the transfer roller. Transcript. In the state where the surface of the steering wheel is pressed against the surface of the transfer roller and the surface of the transfer roller is elastically deformed, the transfer roller is pressed against the steering wheel and rotated, and the ink adhering to the surface of the transfer roller is removed. Adhere to the surface.
JP 2001-27790 A JP 2004-160820 A

  In the method described in Japanese Patent Application Laid-Open No. 2005-228688, the pattern is transferred by pressing the transfer roller against the surface of the steering wheel, so that the pattern can be transferred to a predetermined width while preventing wrinkles. However, even with this method, the pattern cannot be transferred to the entire circumference of the steering wheel with the transfer roller. In order to transfer the pattern to the entire circumference of the steering wheel, it is necessary to transfer the pattern multiple times with a transfer roller. For this reason, the number of times of transfer increases and the transfer cost increases. Furthermore, the method using the transfer roller is suitable for transferring the wood grain pattern to the whole along the circumferential direction of the ring, but it takes much time to transfer the pattern to a part of the ring. This is because it is difficult to finely finish the boundary between the portion that transfers the grain and the portion that does not transfer. The steering wheel has a structure in which a circular ring is connected to a central boss with spokes. This steering wheel is often made of a structure in which the circular ring is not entirely made of wood, but a part of the spoke connecting part is made of plastic and the other part is made of a wood grain pattern. This is because both the spokes and their connecting parts can be easily manufactured while having a beautiful design made of plastic with an integral structure. A steering wheel having this structure is often used in which part of the upper and lower arcs are made of wood and part of the arcs on both sides are made of plastic and connected to the spokes. Since the steering wheel with this structure has a wood pattern on the upper and lower parts, when transferring the grain with the transfer roller, there are four boundaries around the entire circumference, and the boundary between the transfer part and the non-transfer part is beautiful. There is a drawback that it takes a lot of time and effort to finish.

  Furthermore, a major drawback of the conventional transfer method is that it is impossible to eliminate the appearance of the screen mesh depending on the direction of light and the state of reflection. For this reason, it can be seen that this wood grain pattern is not a natural wood pattern, but an artificially processed pattern by printing, so there is a drawback that it cannot be used for a high-grade steering wheel.

The present invention has been developed for the purpose of solving these drawbacks. An important object of the present invention is to provide a transfer method and a transfer sheet capable of transferring a beautiful pattern so as not to be wrinkled even on a large area of a transfer target having a three-dimensional curved surface.
In addition, another important object of the present invention is a transfer method that can prevent generation of wrinkles without using water as a transfer environment, and can transfer a beautiful pattern without wrinkles to the surface of a hygroscopic material that is weak against water. And providing a transfer sheet.
Another object of the present invention is to provide a transfer method and a transfer sheet that can be transferred to a large area of a three-dimensional curved transfer object at a time, efficiently and inexpensively mass-produced, and a beautiful pattern can be transferred to the transfer object.

The present invention has the following configuration in order to achieve the above-mentioned object.
In the transfer method for transferring a pattern to a transfer object described in claim 1 of the present invention, a transfer sheet 2 is disposed on the surface of the transfer object 1, and the transfer sheet 2 faces the transfer object 1. The pressure on the back surface side is made lower than the pressure on the surface side on the opposite side, the transfer sheet 2 is brought into close contact with the surface of the transfer body 1, and the ink of the transfer sheet 2 is transferred to the transfer body 1. The transfer sheet 2 used in this method has an ink through a release layer 22 on the surface of a urethane-based substrate sheet 21 having an elongation at break of 600% or more and an elastic recovery rate of 10% or less. The layer 24 is provided. Further, the transfer sheet 2 is provided with a pattern on the ink layer 24 by ink dots 24A that are heated and melted. While the transfer sheet 2 is in close contact with the surface of the transfer target 1, the transfer sheet 2 is heated to melt and expand the ink dots 24A to reduce the inter-dot gaps 24B of the ink dots 24A. The pattern is also transferred to the transfer target 1 that is performing the process.

  In this specification, the elongation at break of the transfer sheet is the length when the transfer sheet having a width of 15 mm and a length (distance between chucks) of 100 mm is stretched at a speed of 500 mm / min and this starts to break. It means the ratio to the reference length. Temporarily, a transfer sheet having an elongation at break of 600% has a stretched length that is six times the reference length, and therefore breaks when it is stretched to a total length of seven times.

Moreover, in this specification, an elastic recovery factor means the value measured by the following formula | equation.
However, the dimensions of the transfer sheet used for the measurement are a width of 15 mm and a length (distance between chucks) of mm.
Elastic recovery rate (%) = [(l−l ₀ ) / l ₀ ] × 100
In this equation, l ₀ is the initial length, l is the transfer sheet stretched at a speed of 500 mm / min to 300% stretched at room temperature (the total length is 4 times the reference length), and then 500 mm / This is the length when the strain is released by contracting at a rate of min.
From this definition, the smaller the value of the elastic recovery rate, the better the elastic recovery. That is, a transfer sheet having a small elastic recovery rate becomes a sheet that can be contracted to a value close to the original length if the transfer sheet is stretched and stretched for a long time and is not stretched.

  In the transfer method of the present invention, the transfer sheet 2 that is in close contact with the surface of the transfer target 1 is heated to 80 to 120 ° C., the ink dots 24A are thermally melted to expand the transfer area, and the inter-dot gap 24B. Can be reduced.

  In the transfer method of the present invention, the transfer sheet 2 using a base sheet 21 made of a thermoplastic polyurethane or polyurethane elastomer sheet can be used.

  Furthermore, the transfer method of the present invention can transfer a beautiful woodgrain pattern or the like to the entire periphery of the steering wheel 30 using the three-dimensional curved transfer target 1 as the steering wheel 30 of the automobile.

  In the transfer method of the present invention, the transfer sheet 2 in which the offset printing ink layer 24 is provided on the substrate sheet 21 can be used.

  In the transfer sheet according to claim 6 of the present invention, the ink dots 24A of the ink layer 24 provided on the surface via the release layer 22 are brought into close contact with the surface of the transfer target 1 by a pressure difference. Transfer to the surface of the transfer target 1. In this transfer sheet, an ink layer 24 is provided on a surface of a urethane base sheet 21 having an elongation at break of 600% or more and an elastic recovery rate of 10% or less via a release layer 22. Yes. Further, the ink layer 24 is provided with a pattern of ink dots 24A that are melted by heat when heated. When this transfer sheet is heated while being in close contact with the surface of the transfer target 1, the ink dots 24A are melted and enlarged by heat to reduce the inter-dot gaps 24B of the ink dots 24A. The pattern is transferred to the transfer body 1.

  The transfer sheet of the present invention can reduce the inter-dot gap 24B by thermally melting the ink dots 24A of the ink layer 24 in a state of being heated to 80 to 120 ° C. and expanding the transfer area.

  In addition, the transfer sheet of the present invention can use thermoplastic polyurethane or polyurethane elastomer as the base material sheet 21.

  Furthermore, the transfer sheet 2 of the present invention can be provided with the ink layer 24 of the ink dots 24 </ b> A that are offset printed on the base material sheet 21.

  The transfer method and transfer sheet of the present invention have a feature that a beautiful pattern can be transferred so as not to be wrinkled even on a large area of a transfer target having a three-dimensional curved surface. This is because the present invention has a pattern of ink dots that melt on heat when heated on a surface of a urethane-based substrate sheet having an elongation at break of 600% or more and an elastic recovery rate of 10% or less. The transfer layer is heated in a state where it is in close contact with the surface of the transfer object, and the ink dots are melted and enlarged to reduce the gaps between the ink dots. This is because the pattern is transferred to the transfer target.

  Even if the transfer sheet having the above structure is a transfer object having a three-dimensional curved surface or a transfer object with large unevenness, the transfer sheet is locally stretched and closely adhered to the surface, and is contracted like the back surface of the transfer object. In the portion, the sheet can be in close contact with the sheet while preventing the sheet from shrinking. Therefore, in the present invention, even a transfer object having a complicated three-dimensional curved surface or an aperture, a transfer sheet is closely adhered to the front and back surfaces of the transfer sheet so as not to be wrinkled, and a clean pattern is transferred over a large area. it can. In this way, the transfer method and transfer sheet of the present invention, which can be transferred onto a large area of a three-dimensional curved surface at a time, reduce the cost of transfer, and realize the feature that beautiful patterns can be mass-produced efficiently and inexpensively. it can.

  Furthermore, the transfer method and transfer sheet of the present invention melt and expand the ink dots by heating at the time of transfer to fill the gaps between the ink dots. A beautiful pattern as much as possible can be realized, giving a sense of quality and authenticity.

  In addition, since the present invention does not use water as a transfer environment, it can prevent generation of wrinkles, transfer beautiful patterns without wrinkles, and can also transfer beautifully to the surface of hygroscopic materials that are vulnerable to water. is there.

  Furthermore, in the conventional hydraulic transfer method, the membrane type vacuum forming method, the in-mold coating method, etc., it was impossible to repair if air accumulation and wrinkles were formed, but in the present invention, the substrate sheet is peeled off from the transfer object. As a result, only the ink layer can be transferred, so that repair by partial transfer of only defective portions, which could not be done in the past, is possible, and the cost of repair can be reduced while improving the finish.

  Furthermore, in the present invention, since the pattern of ink dots is transferred to the surface of the transfer object, the surface is not covered with a transparent sheet or the like. If necessary, ink is applied with a brush or the like after transfer. It can also be repaired, and it can also easily repair wrinkles on complex curved surfaces.

  Embodiments of the present invention will be described below with reference to the drawings. However, the examples shown below exemplify a transfer method and a transfer sheet for embodying the technical idea of the present invention, and the present invention does not specify the transfer method and the transfer sheet as follows. .

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  The transfer device shown in FIGS. 1 to 3 shows a specific example in which a wood grain pattern or the like is transferred to the surface of a transfer object 1 using a steering wheel 30 of an automobile part. However, the present invention does not specify the transfer object as a steering wheel. The object to be transferred is most suitable for transferring decorative parts having a complicated three-dimensional curved surface such as all objects that transfer the pattern of the transfer sheet, such as home appliances and exteriors of Buddhist altars.

  The steering wheel 30 is formed by connecting elongated cylinders in a ring shape to form a circular ring 31, and a central boss 33 is connected to the circular ring 31 via a spoke 32. It is extremely difficult to transfer a pattern such as a grain on the entire circumference of the circular ring 31, that is, 360 degrees in the cross section of the circular ring 31. 1 to 3, it is difficult for the steering wheel 30 to transfer the lower edge portion. This is because it is difficult to bring the transfer sheet 2 into close contact with the entire circumference. A method that can transfer a pattern to the entire circumference of the steering wheel 30 can transfer a beautiful pattern to a transfer object having an extremely complicated solid curved surface. That is, the steering wheel 30 is a transfer object that is most difficult to transfer as a transfer object having a three-dimensional curved surface. The method and the transfer sheet of the present invention can cleanly transfer the pattern onto the three-dimensional curved transfer target 1 such as the steering wheel 30. This makes it possible to transfer the pattern neatly to other transferred materials.

  The transfer device shown in FIGS. 1 to 3 depressurizes the back side of the transfer sheet 2 to a vacuum. The transfer sheet 2 whose pressure on the back side has been reduced is pressed by the pressure on the front side, which is atmospheric pressure, and is in close contact with the surface of the transfer target 1. In these drawings, the transfer sheet 2 is transferred to the surface of the transfer target 1 by a vacuum forming method.

  The transfer device described above includes a set base 3 for setting the transfer object 1, a main body case 4 in which the set base 3 is disposed, and a transfer sheet 2 set on the set base 3 of the main body case 4. A lid case 5 provided with an airtight chamber, a vacuum pump 6 for decompressing the inside of the airtight chamber of the main body case 4, a heating lamp 7 for heating the transfer sheet 2 set on the setting table 3, and an opening / closing operation for opening and closing the airtight chamber And a mechanism 8.

  The setting table 3 is set in a horizontal posture so that the steering wheel 30 as the transfer target 1 can be attached and detached. The set base 3 shown in the figure fixes a boss 33 at the center of the steering wheel 30 with screws. The boss 33 is provided with a protective cover 34 inside the circular ring 31. The protective cover 34 has a disc shape whose outer diameter is smaller than the inner shape of the steering wheel 30 and covers the boss 33 and the center portion of the spoke 32 of the steering wheel 30. This protective cover 34 prevents the transfer sheet 2 from being forcibly sucked into the steering wheel 30 and damaged. This is because the transfer sheet 2 is in close contact with the surface of the protective cover 34 inside the steering wheel 30.

  The set base 3 shown in the figure is connected to the main body case 4 via the vertical mechanism 9. The vertical mechanism 9 reciprocates the set table 3 up and down. The set base 3 shown in the figure has a vertical shaft 10 fixed at the center, and is connected to the body case 4 so that the vertical shaft 10 can reciprocate in the vertical direction. Further, the vertical shaft 10 is connected to a reciprocating mechanism 11 such as a cylinder at the lower end. The reciprocating mechanism 11 reciprocates the set table 3 up and down via the vertical shaft 10 to bring the transfer sheet 2 into close contact with the steering wheel 30 of the transfer target 1 over a wider area.

  The main body case 4 has a box shape that opens upward, and has a peripheral wall 4 </ b> A protruding from the periphery. The peripheral wall 4 </ b> A has an upper surface as a close contact surface of the transfer sheet 2. The main body case 4 has the transfer sheet 2 in close contact with the close contact surface on the upper surface of the peripheral wall 4A without any gap, and the inside surrounded by the peripheral wall 4A and the transfer sheet 2 serves as an airtight chamber. Further, the main body case 4 is provided with a suction opening 12 along the lower edge of the circular ring 31 of the steering wheel 30 in order to exhaust and decompress the air in the airtight chamber. The suction opening 12 is connected to the vacuum pump 6. The main body case 4 in the figure has a slit shape along the lower surface of the circular ring 31 of the steering wheel 30 that is the transfer body 1.

  The lid case 5 has a box shape with an opening at the bottom, and is provided with a protruding strip 5A around the periphery. The lower surface of the protrusion 5A is in close contact with the upper surface of the peripheral wall 4A of the main body case 4, and the transfer sheet 2 is sandwiched between the protrusion 5A and the peripheral wall 4A. Therefore, the convex strip 5A of the lid case 5 and the peripheral wall 4A of the main body case 4 have the same planar shape so that the transfer sheet 2 can be sandwiched therebetween. 5 A of ridges make the lower surface the smooth plane which follows the contact | adherence surface of 4 A of surrounding walls.

  Further, the lid case 5 shown in the figure has a heating lamp 7 for heating the transfer sheet 2 fixed to the inner surface of the top plate 5B. The heating lamp 7 emits infrared rays from the upper surface to the transfer sheet 2 to heat the transfer sheet 2 to a set temperature in a short time.

  The lid case 5 connects the opening / closing mechanism 8. As shown in FIG. 1, the opening / closing mechanism 8 shown in FIG. 1 raises the lid case 5 and opens the protruding strip 5 </ b> A of the lid case 5 and the peripheral wall 4 </ b> A of the main body case 4. In this state, the steering wheel 30 of the transfer target 1 is detached from the set table 3, and the transfer sheet 2 is stretched. When the transfer sheet 2 is brought into close contact with the steering wheel 30, the lid case 5 is lowered as shown in FIGS. The lid case 5 that descends sandwiches the transfer sheet 2 between the ridges 5 </ b> A and the peripheral wall 4 </ b> A of the main body case 4, and the transfer sheet 2 and the main body case 4 closely contact the airtight chamber.

The transfer device described above transfers the pattern of the transfer sheet 2 to the steering wheel 30 of the transfer target 1 in the following steps as shown in FIGS.
(1) As shown in FIG. 1, the opening / closing mechanism 8 raises the lid case 5 and separates the protrusion 5 </ b> A from the peripheral wall 4 </ b> A to open the upper opening of the main body case 4.
(2) The steering wheel 30 of the transfer body 1 is set on the set base 3. The steering wheel 30 shown in the figure is set on the set base 3 by screwing the boss 33. At this time, the set stand 3 is in the raised position.
(3) The transfer sheet 2 is stretched on the peripheral wall 4 A of the main body case 4.

(4) Thereafter, the opening / closing mechanism 8 lowers the lid case 5. The lid case 5 that descends sandwiches the transfer sheet 2 between the ridges 5A and the peripheral wall 4A, the lower part of the transfer sheet 2 is an airtight chamber, and the steering wheel 30 is disposed in the airtight chamber.
(5) The vacuum pump 6 exhausts the air in the hermetic chamber. When the airtight chamber is depressurized, the transfer sheet 2 is brought into close contact with the surface of the steering wheel 30 as shown in FIG.
(6) The transfer sheet 2 is heated by the heating lamp 7 and heated hot air is supplied into the lid case 5. The heated transfer sheet 2 is more flexible and easily stretched, and is in close contact with the surface of the steering wheel 30 over a wide area. Further, as shown in FIG. 3, the set table 3 is reciprocated up and down to bring the transfer sheet 2 into close contact with the lower surface of the steering wheel 30. In this state, the vacuum pump 6 further exhausts the air in the hermetic chamber. In a state where the airtight chamber is decompressed, the set table 3 is moved up and down, and the heated transfer sheet 2 is brought into close contact with the entire circumference of the steering wheel 30.
(7) The transfer sheet 2 that is in close contact with the entire circumference of the steering wheel 30 in a heated state transfers the surface pattern onto the surface of the steering wheel 30. As shown in FIG. 4, the transfer sheet 2 is provided with an ink layer 24 having an ink dot pattern that is heated and melted. Since this transfer sheet 2 is pressed and brought into close contact with the surface of the steering wheel 30 in a heated state, as shown in FIG. 5, the ink dots 24A are melted and expanded, and the gap 24B between dots is reduced. The pattern is transferred to the transfer body 1.
(8) After the pattern is transferred, the operation of the vacuum pump 6 is stopped and the airtight chamber is brought to atmospheric pressure. In this state, the transfer sheet 2 does not adhere to the steering wheel 30. In this state, the set base 3 is raised, and the opening / closing mechanism 8 raises the lid case 5, separating the lid case 5 from the main body case 4 and opening the top of the main body case 4.
(9) The transfer sheet 2 to which the pattern has been transferred is removed, and the steering wheel 30 is removed from the set base 3 and taken out from the main body case 4.

  FIG. 4 shows an enlarged cross-sectional view of the transfer sheet 2 used for the above applications. The transfer sheet 2 in this figure is provided by laminating a base sheet 21 / release layer 22 / ink receiving layer 23 / ink layer 24 (ink dot 24A) / adhesive layer 25 in order from the top in the figure. Yes.

  The material of the base sheet 21 is thermoplastic polyurethane or polyurethane elastomer, which is not melted by heating at the time of transfer, and has an elongation at break of 600% or more at room temperature and an elastic recovery rate of 10% or less. Is. For the base sheet 21, “Esmer URS” manufactured by Nippon Matai Co., Ltd. is preferably used. This base material sheet 21 does not melt by heating at the time of transfer, and has a property excellent in bending resistance and tear resistance against local distraction when vacuum forming is performed at room temperature.

  The reason why the elongation at break of the base sheet 21 is set to 600% or more is that when the elongation at break is smaller than this, transfer cannot be performed to the entire periphery to the back like the transferred object 1 or the steering wheel 30 with large unevenness. Because. Moreover, the base material sheet 21 which has only a high elongation at break cannot be used. That is, the uneven transfer target 1 extends sufficiently in the extended portion and adheres closely to the transfer target 1, but does not contract in the contracting portion such as the back surface of the steering wheel 30 and is wrinkled. This is because a beautiful pattern cannot be transferred. Accordingly, it is important for the transfer sheet 2 to have not only the elongation at break but also the elastic recovery rate of 10% or less. The base material sheet 21 is not necessarily required to be the above-described material as long as the elongation at break and the elastic recovery rate are within the above-described ranges. The base sheet 21 is not necessarily melted by heating during transfer, and the elongation at break is normal temperature. Other plastic sheets that have 600% or more and an elastic recovery rate of 10% or less can also be used.

  The release layer 22 is heated in a state where the transfer sheet 2 is in close contact with the transfer target 1 to transfer the ink layer 24 to the surface of the transfer target 1, and is heated to release the ink layer 24. It is a layer to mold. Silicon resin or wax resin is used for this layer.

  The ink layer 24 expresses a color pattern with six or more ink dots 24A. However, the ink layer may be a color pattern of ink dots 24A having 5 colors or less. The ink layer 24 that expresses the color pattern with the ink dots 24A is made of a special printing plate made of aluminum plate of 6 colors or more with computer-processed pattern data, and can be put on a sheet for exclusive use of fixed size cut. It is provided by sheet-like printing that provides a fine finish with high resolution by full color offset printing. However, the ink layer 24 can be provided by screen printing or an inkjet printer instead of offset printing. In this ink layer 24, each color ink dot 24A is independently applied to the substrate sheet 21 in a specific arrangement to form a color pattern. Accordingly, an inter-dot gap 24B in which no dots are attached is formed between the ink dots 24A. In the screen-printed ink layer 24, color dots are arranged on the screen mesh, so that an inter-dot gap 24B is formed between the screen meshes. The ink layer 24 having the inter-dot gap 24B does not crack or break in the pattern even when the transfer sheet 2 is stretched. This is because the inter-dot gap 24B extends and widens. Further, even if cracks or cracks occur in the fine ink dots 24A, this does not deteriorate the quality of the pattern. This is because the ink dots 24A of the ink layer 24 are fine, so that the pattern is expressed as a set of ink dots 24A.

  However, when the ink layer 24 composed of the ink dots 24 </ b> A is transferred to the surface of the transfer target 1 such as the steering wheel 30, it is not possible to eliminate the appearance of the screen mesh depending on the direction of light and the state of reflection. When the screen mesh can be seen, for example, the wood grain pattern of natural wood is found to be an artificially processed pattern by printing, and the quality is significantly reduced.

  In order to eliminate this drawback, the ink layer 24 is provided with a pattern of ink dots 24A in which the ink surface layer is thermally melted when heated to 80 to 120 ° C., for example. The ink layer 24 is heated at the time of transfer, and the ink dots 24A are melted. The melted ink dots 24A are crushed by the pressing force at the time of transfer, and the area increases. The enlarged ink dot 24A fills the inter-dot gap 24B without ink. In the color pattern transferred in this state, the inter-dot gap 24B such as a screen mesh becomes inconspicuous. This makes it possible to give a sense of quality.

  The ink layer 24 is transferred by bringing the transfer sheet 2 into close contact with the surface of the transfer target 1 by a vacuum forming method. In the transfer of the ink layer 24, the base material sheet 21 having a high elongation at break is decompressed by the vacuum pump 6 as shown in FIG. The surface of a certain steering wheel 30 is covered. In this state, the transfer sheet 2 does not cover the entire circumference of the circular ring 31 but covers up to about 240 degrees. Then, while supplying hot air, the heating lamp 7 irradiates infrared rays. In this state, the steering wheel 30 and the transfer sheet 2 of the transfer target 1 are rapidly heated, and the degree of elongation of the base material sheet 21 is increased. The base sheet 21 that has been easily stretched adheres to a wider area of the steering wheel 30 of the transfer body 1 due to the differential pressure between the hot air and the vacuum force of the vacuum pump 6. Further, in this state, the stretched transfer sheet 2 shrinks at a portion along the lower portion of the steering wheel 30 to return to the original state due to the elastic recovery force. Therefore, the transfer sheet 2 is brought into close contact with the lower back surface of the steering wheel 30 without wrinkling. The adhesive layer 25 provided on the surface of the ink layer 24 or the surface of the steering wheel 30 of the transfer target 1 develops an adhesive force by being heated by hot air and the heating lamp 7, and the ink layer 24 is transferred. Adhere to the steering wheel 30 of the body 1. Thereafter, when the substrate sheet 21 is peeled off from the steering wheel 30 of the transfer target 1 after cooling, only the ink layer 24 is transferred. In this way, by using the base sheet 21 having a high degree of elongation at normal temperature and a high elastic recovery property as the base sheet 21 of the transfer sheet 2, wrinkles and cracks are observed over the entire surface from the front surface to the back surface of the three-dimensional curved surface. The pattern by the ink dots 24A of the ink layer 24 of the transfer sheet 2 can be transferred without causing it.

  Further, the ink dots 24A transferred to the steering wheel 30 of the transfer target 1 are melted to reduce the inter-dot gap 24B, and the screen mesh and the like become inconspicuous. For this reason, the color wood grain pattern transferred to the surface of the steering wheel 30 of the transfer target 1 has a high quality finish that is indistinguishable from the real wood grain pattern because the inter-dot gaps 24B of the ink dots 24A cannot be seen. Furthermore, since the pattern of the ink dots 24A is transferred to the surface of the steering wheel 30 of the transfer target 1, and the surface is not covered with a transparent sheet or the like, if necessary, ink can be applied with a brush or the like after transfer. It can also be repaired. For this reason, it is possible to repair wrinkles on complicated curved surfaces, and further, it is possible to transfer recesses and complicated intrusions that are impossible with hydraulic transfer.

  The adhesive layer 25 is provided on the surface of the ink layer 24, but it can also be applied to the surface of the transfer target 1. The adhesive layer 25 is heated to develop an adhesive force and adheres the ink layer 24 to the surface of the transfer target 1. Therefore, for the adhesive layer 25, for example, a heat-encapsulating acrylic adhesive, an epoxy adhesive, or a hot melt adhesive is used.

  The above transfer sheet 2 can be adhered and transferred cleanly even on an uneven surface such as an embossed surface. Further, the transfer sheet 2 can be brought into close contact with almost the entire surface of the steering wheel 30 or the like to be transferred 1 only by a pressure difference that reduces the pressure on the lower surface by operating the vacuum pump 6. By heating, the degree of elongation of the base material sheet 21 is further increased, and the substrate sheet 21 can be adhered to the entire surface of the transfer target 1. By maintaining the heating time, the adhesive force of the adhesive layer 25 can be expressed. Thereafter, the ink layer 24 alone can be transferred by cooling and removing the transfer substrate sheet 21 from the transfer target 1.

The wood grain pattern is transferred to the steering wheel 30 of the transfer target 1 in the following steps.
A release layer 22 and an ink receiving layer 23 are coated on a base sheet 21 (Esmer URS: manufactured by Nihon Matai Co., Ltd., thickness 50 μm, elongation at break 680%, elastic recovery 10%) with a roll coater. This base material sheet 21 is cut into a fixed size, and a five-color aluminum plate printing plate is made with computer-processed wood grain pattern data, and a full-color offset printing of six colors is performed with ink that can be placed on the ink layer 24 to form an ink layer 24. Provide.

  As the transfer object 1, a steering wheel 30 made of urethane foam is used. In advance, an acrylic adhesive (manufactured by Soken Chemicals Co., Ltd., SK Dyne 1375) is provided as an adhesive layer 25 on the surface of the urethane molded portion by spray coating.

  As shown in FIG. 1, after the steering wheel 30 of the transfer target 1 is set at a fixed position on the set base 3, the transfer sheet 2 is arranged with the ink layer 24 facing the transfer target 1. Thereafter, as shown in FIG. 2, after the lid case 5 is lowered, the air in the airtight chamber is exhausted by the vacuum pump 6. The air is exhausted through the suction opening 12 of the slit that matches the shape of the steering wheel 30 provided on the set base 3. In this state, the vacuum of the hermetic chamber is set to about 60 Torr. In this state, as shown in FIG. 2, the transfer sheet 2 is in close contact with the circular ring 31 of the steering wheel 30 to approximately 240 degrees.

  Thereafter, compressed air of hot air heated to 110 ° C. and pressurized to 2 atm is supplied into the lid case 5, and infrared rays are emitted by the heating lamp 7. The compressed air of the hot air presses the upper surface of the transfer sheet 2 that has been easily heated and stretched against the surface of the steering wheel 30. In this state, the transfer sheet 2 is in close contact with the back surface of the circular ring 31 of the steering wheel 30 at 360 degrees around the entire circumference without generating wrinkles or air pockets. This state is maintained for 60 seconds, and the adhesive layer 25 is cured by developing an adhesive force.

  After that, when the substrate sheet 21 is cooled and peeled off from the steering wheel 30 of the transfer target 1, the transfer pattern 2 does not show defects such as omission and only the ink layer 24 is transferred cleanly. The In addition, the ink dots 24A are melted and expanded, the inter-dot gaps 24B are not reduced, and a high-quality finish that does not look like a real wood grain with no printed dots seen.

The wood grain pattern is transferred to the steering wheel 30 of the transfer target 1 in the following steps.
A release layer 22 and an ink receiving layer 23 are coated on a base sheet 21 (Esmer URS: manufactured by Nihon Matai Co., Ltd., thickness 50 μm, elongation at break 680%, elastic recovery 10%) with a roll coater. This base material sheet 21 is cut into a fixed size, and a grain pattern is silk-screen printed on the surface. Silk screen printing is performed by color-separating a high-quality wood grain pattern, creating a five-color silk screen printing plate from computer-processed wood grain pattern data, and adding ink.

  As the transfer object 1, a steering wheel 30 made of urethane foam is used. An epoxy resin (manufactured by Dainippon Paint Co., Ltd., dipping clear) is spray coated on the surface of the urethane molded portion as an adhesive layer 25 in advance.

  As shown in FIG. 1, after setting the steering wheel 30 of the transfer target 1 at a fixed position of the set base 3 in a state where the epoxy resin of the adhesive layer 25 is uncured, the transfer sheet 2 is moved to its ink. The layer 24 is disposed toward the transfer target 1. Thereafter, as shown in FIG. 2, after the lid case 5 is lowered, the air in the airtight chamber is exhausted by the vacuum pump 6. The air is exhausted through the suction opening 12 of the slit that matches the shape of the steering wheel 30 provided on the set base 3. In this state, the vacuum of the hermetic chamber is set to about 60 Torr. In this state, as shown in FIG. 2, the transfer sheet 2 is in close contact with the circular ring 31 of the steering wheel 30 to approximately 240 degrees.

  Thereafter, compressed air of hot air heated to 80 ° C. and pressurized to 5 atm is supplied to the inside of the lid case 5, and infrared rays are emitted by the heating lamp 7. The compressed air of the hot air presses the upper surface of the transfer sheet 2 that has been easily heated and stretched against the surface of the steering wheel 30. In this state, the transfer sheet 2 is in close contact with the back surface of the circular ring 31 of the steering wheel 30 at 360 degrees around the entire circumference without generating wrinkles or air pockets. This state is maintained for 30 seconds, and the epoxy resin of the adhesive layer 25 is cured.

  After that, when the substrate sheet 21 is cooled and peeled off from the steering wheel 30 of the transfer target 1, the transfer pattern 2 does not show defects such as omission and only the ink layer 24 is transferred cleanly. The Also, the ink dots 24A are melted and expanded, the inter-dot gaps 24B are not reduced, dots that are specific to gravure printing are not seen, and the stretch of the pattern is not bothered by the thick ink that is specific to silk screen printing. The result is a high quality finish that is mistaken for real wood grain.

Comparative example

  Under the same conditions as in Example 1, a polyester resin sheet (thickness 50 μm, elongation at break 200%, elastic recovery rate 80%) was used as the base sheet, and the ink layer was transferred under the same conditions. The transfer ring is only in contact with the circular ring of the steering wheel up to about 180 degrees. When compressed air (2 atm) heated to 110 ° C. is supplied from the lid case, the transfer sheet adheres to the steering wheel. Although the area of the ink layer increases, many wrinkles and air pockets occur on the back surface, and the ink layer cannot be transferred cleanly.

It is a schematic sectional drawing of the transfer apparatus used for the transfer method concerning one Example of this invention. It is a schematic sectional drawing which shows the process in which the transfer apparatus shown in FIG. 1 transfers a pattern to a to-be-transferred body. It is a schematic sectional drawing which shows the process in which the transfer apparatus shown in FIG. 1 transfers a pattern to a to-be-transferred body. It is an expanded sectional view of the transfer sheet. It is an expanded sectional view which shows the state which transcribe | transferred the pattern to the to-be-transferred material with the transfer sheet shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transfer object 2 ... Transfer sheet 3 ... Set stand 4 ... Main body case 4A ... Peripheral wall 5 ... Lid case 5A ... Projection
5B ... Top plate 6 ... Vacuum pump 7 ... Heating lamp 8 ... Opening / closing mechanism 9 ... Vertical mechanism 10 ... Vertical axis 11 ... Reciprocating mechanism 12 ... Suction opening 21 ... Base sheet 22 ... Release layer 23 ... Ink receiving layer 24 ... Ink layer 24A ... Ink dots
24B: Interdot space 25 ... Adhesive layer 30 ... Steering wheel 31 ... Circular ring 32 ... Spoke 33 ... Boss 34 ... Protective cover

Claims (9)

The transfer sheet (2) is placed on the surface of the transfer target (1), and the pressure on the back side where the transfer sheet (2) faces the transfer target (1) is higher than the pressure on the opposite side. The transfer sheet (2) is brought into close contact with the surface of the transfer target (1), and the transfer sheet (2) ink is transferred to the transfer target (1).
As a transfer sheet (2), an ink layer (22) is disposed on the surface of a urethane base sheet (21) having an elongation at break of 600% or more and an elastic recovery rate of 10% or less via a release layer (22). 24), the ink layer (24) of the transfer sheet (2) is patterned with ink dots (24A) that are heated and thermally melted,
With the transfer sheet (2) in close contact with the surface of the transfer target (1), the transfer sheet (2) is heated to melt and expand the ink dots (24A). A transfer method in which a pattern is transferred to a transfer target that reduces the inter-dot gap (24B).   The transfer sheet (2) that is in close contact with the surface of the transfer target (1) is heated to 80 to 120 ° C., and the ink dots (24A) are thermally melted to widen the transfer area and the inter-dot gap (24B). A transfer method for transferring a pattern to a transfer target according to claim 1, wherein   The transfer method for transferring a pattern to a transfer target according to claim 1, wherein the transfer sheet (2) is used wherein the base sheet (21) is a sheet of thermoplastic polyurethane or polyurethane elastomer.   The transfer method for transferring a pattern to a transfer object according to claim 1, wherein the transfer object (1) is a steering wheel (30) of an automobile.   The transfer method for transferring a pattern to a transfer target according to claim 1, wherein a transfer sheet (2) provided with an ink layer (24) formed by offset printing on a base sheet (21) is used. The ink dots (24A) of the ink layer (24) provided on the surface through the release layer (22) are adhered to the surface of the transfer target (1) by a pressure difference, and the surface of the transfer target (1). In the transfer sheet to be transferred to
An ink layer (24) is provided on the surface of a urethane-based substrate sheet (21) having an elongation at break of 600% or more and an elastic recovery rate of 10% or less via a release layer (22). The ink layer (24) forms a pattern with ink dots (24A) that melt with heat when heated,
When heated while being in close contact with the surface of the transfer object (1), the ink dots (24A) are melted and expanded by heat to reduce the inter-dot gap (24B) of the ink dots (24A). A transfer sheet for transferring a pattern onto the transfer target (1).   The ink layer (24) heats the transfer sheet (2) at 80 to 120 ° C., so that the ink dots (24A) are thermally melted to expand the transfer area and reduce the inter-dot gap (24B). The transfer sheet according to claim 6.   The transfer sheet according to claim 6, wherein the base sheet (21) is a sheet of thermoplastic polyurethane or polyurethane elastomer. The transfer sheet according to claim 6, wherein an ink layer (24) of ink dots (24 A) subjected to offset printing is provided on the base sheet (21).

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