JP2010082829A - Method for producing decorative molded sheet with micro unevenness formed - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a decorative molded sheet which is easy to match directions between a micro unevenness part and a pattern layer, does not cause the problem of the mold releasability of a surface resin layer, and can improve the throughput of a nanoimprint process. <P>SOLUTION: After the decorative molded sheet 110 with the surface resin layer 2 formed thereon is manufactured, a nanoimprint mold 20 is pressed to the surface resin layer 2 to form micro unevenness. After the nanoimprint mold 20 is separated from the surface resin layer 2, the surface resin layer 2 with the micro unevenness formed thereon is irradiated with ionizing radiation 25. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a decorative molded sheet having a surface with a minute unevenness such as a partial mat, and after producing a decorative molded sheet having a surface resin layer formed on the outermost surface, the nanoimprint method is used. It is characterized by forming minute irregularities by post-processing.

  As a partial mat hard coat material, in order to match the pattern of the previously printed partial mat layer and the hard coat layer to be printed later, especially the pattern of the pattern layer, a series of processes from the partial mat layer to the hard coat layer and the pattern layer are performed. A technique for developing a partial mat hard coat material by so-called in-line printing using a printing press has been developed (see Patent Document 1).

  In this technology, a transfer material is configured such that a partial mat layer made of a water-soluble resin in which a mat material is dispersed, a hard coat layer, and an adhesive layer are laminated on a substrate sheet having peelability. The material is sandwiched between injection molds, a molding resin is injected into the cavity, and an injection molded product is obtained. At the same time, a transfer material is adhered to the surface, the mold is opened, the molded product is taken out, and the base sheet is peeled off. Thereafter, active energy rays are irradiated, and then the water-soluble resin of the partial mat layer remaining on the hard coat layer is removed by washing with water.

JP 2001-260596 A

  However, in the above method, when the hard coat layer is formed by in-line printing, it is difficult to obtain sufficient strength because the thickness of the hard coat layer can be increased only to about 2 μm in order to increase the drying speed. Therefore, in order to improve the hard coat properties, the thickness of the hard coat layer is necessary. For that purpose, the hard coat layer must be once removed from the printing press and thickly applied with a coater or the like. However, there is a problem in that the partial mat layer and the pattern layer are out of register.

  In order to solve such a problem, the present invention does not form a partial mat layer at the stage of forming a surface resin layer first, but forms a surface resin layer on the outermost surface of the decorative molded sheet by a method such as transfer. After the formation, fine irregularities such as a partial mat are formed on the surface resin layer by post-processing by a nanoimprint method.

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

  The method for producing a decorative molded sheet according to the present invention is to produce a decorative molded sheet having a surface resin layer formed on at least the outermost surface of the molded sheet, and then press the nanoimprint mold on the surface resin layer to form fine irregularities. After forming and separating the nanoimprint mold from the surface resin layer, a step of irradiating ionizing radiation to the surface resin layer on which the minute irregularities are formed is taken.

  In the method for producing a decorative molded sheet of the present invention, at least a surface resin layer is formed on a substrate sheet, the surface resin layer is transferred to the surface of the molded sheet, the substrate sheet is peeled off, and the surface resin layer is formed on the outermost surface. After forming the decorative molded sheet formed with, after pressing the nanoimprint mold on the surface resin layer of the decorative molded sheet and separating the nanoimprint mold from the surface resin layer, the micro unevenness is formed. A step of irradiating the surface resin layer with ionizing radiation.

  Further, in the above invention, when the nano-imprint mold is pressed on the surface resin layer to form minute irregularities, the curing polymerization reaction is performed by irradiating with ionizing radiation in an unreacted state and in a tack-free state. May be promoted.

  The decorative molded sheet of the present invention has a configuration manufactured by the method for manufacturing a decorative molded sheet according to any one of the above inventions.

  In the above invention, the surface resin layer has a (meth) acryl equivalent of 100 to 300 g / eq, a hydroxyl value of 20 to 500, a polymer having a weight average molecular weight of 5,000 to 50,000 and a polyfunctional isocyanate, or a melting point of 40. A mixture of an active energy ray-curable resin having a molecular weight of 5,000 to 100,000 and a photoinitiator or a glycidyl (meth) acrylate polymer obtained by addition reaction of an α, β-unsaturated monocarboxylic acid Or a resin composition containing any of the above.

  In the above invention, the minute unevenness formed on the surface resin layer may be a mat.

  In the invention described above, the minute irregularities formed on the surface resin layer may have a low reflection moth-eye structure.

  In the invention according to claims 1 to 2, after producing a decorative molded sheet on which a surface resin layer is formed, the nanoimprint mold is pressed on the surface resin layer to form minute irregularities, and the nanoimprint mold is After separating from the surface resin layer, ionizing radiation is irradiated to the surface resin layer on which the fine irregularities are formed. Therefore, there is an effect that it is easy to match the registration of the minute uneven portion and the pattern layer and the problem of releasability of the surface resin layer does not occur. Further, since the step of pressing the nanoimprint mold to form minute irregularities and the step of irradiating with ionizing radiation are separate, there is an effect that the throughput of the nanoimprint step can be improved.

  The invention according to claim 3 is characterized in that when the nanoimprint mold is pressed, it is in an unreacted state of curing polymerization and in a tack-free state. Therefore, since it is not a tack state as used in conventional optical nanoimprint, there is an advantage that the release from the nanoimprint mold is smooth. In addition, since it is in a state where it has not been cured and polymerized, it is in a state where it is deformed only by pressing, so there is no need for heating as in conventional thermal nanoimprinting, and as a result, steps such as cooling become unnecessary. In addition, there is an effect that the dimensional accuracy is also improved.

  In the invention according to claim 5, the surface resin layer has a (meth) acrylic equivalent of 100 to 300 g / eq, a hydroxyl value of 20 to 500, a polymer having a weight average molecular weight of 5,000 to 50,000 and a polyfunctional isocyanate, or a melting point of 40. A mixture of an active energy ray-curable resin having a molecular weight of 5,000 to 100,000 and a photoinitiator or a glycidyl (meth) acrylate polymer obtained by addition reaction of an α, β-unsaturated monocarboxylic acid It consists of a resin composition containing any of these. Therefore, it is not only easy to perform nanoimprint processing, but also has an effect of becoming a surface resin layer having a hard coat property after curing polymerization.

  The invention according to claim 6 or claim 7 is characterized in that the minute irregularities formed on the surface resin layer have a mat or low-reflection moth-eye structure. Therefore, the surface resin layer is easy to be nanoimprinted and has a hard coat property. However, there is an effect that the mat has a design property or low reflection functionality.

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

  1 to 4 are cross-sectional views showing a method for producing a decorative molded sheet of the present invention. In the figure, 1 is a base sheet, 2 is a surface resin layer, 3 is a pattern layer, 5 is a fine uneven portion, 9 is a release layer, 11 is an anchor layer, 12 is an adhesive layer, 20 is a nanoimprint mold, 25 is Ionizing radiation, 30 is a transfer sheet, 35 is a molded sheet, and 110 is a decorative molded sheet. In addition, the same code | symbol is attached | subjected about the same component in each figure.

  In the first embodiment of the present invention, a decorative molded sheet 110 in which the surface resin layer 2 formed on at least the outermost surface is provided on the molded sheet 35 and the pattern layer 3 is appropriately provided in addition thereto was produced. After (refer FIG. 2 (a)-(c)), the nanoimprint metal mold | die 20 is pressed on the surface resin layer 2 of the decorative molding sheet 110, and the fine uneven part 5 is formed (refer FIG. 1 (a)), and the said After the nanoimprint mold 20 is separated from the surface resin layer 2, ionizing radiation 25 is irradiated to the fine uneven portions 5 of the surface resin layer 2 (see FIG. 1B).

  Further, in the second embodiment of the present invention, a transfer sheet 30 is first prepared in which at least the surface resin layer 2 is provided on the base sheet 1 and the pattern layer 3 is appropriately laminated thereon (see FIG. 3 (a)), the transfer sheet 30 is laminated on the surface of the molded sheet 35, and after applying heat or pressure (see FIG. 3 (b)), the base sheet 1 is peeled off, and the surface of the transfer sheet 30 is removed. After the resin layer 2 and the pattern layer 3 are transferred to the surface of the molded sheet 35 to produce a decorative molded sheet 110 (see FIG. 3C), the nanoimprint mold 20 is applied to the surface resin layer 2 of the decorative molded sheet 110. Is pressed to form a fine uneven portion 5 (see FIG. 4A), and after the nanoimprint mold 20 is separated from the surface resin layer 2, ionizing radiation is applied to the fine uneven portion 5 of the surface resin layer 2. 25 (Fig. 4 ( ) Reference).

  In the first embodiment, the surface resin layer 2 is configured to be the outermost surface of the decorative molded sheet 110. In the second embodiment, the surface resin layer 2 is configured to peel from the base sheet 1 or the release layer 9 provided as necessary to become the outermost surface of the decorative molded sheet 110. The surface resin layer 2 is in a state in which no curing polymerization is performed and a tack-free state when the nano-imprint mold 20 is pressed to form a fine concavo-convex portion 5. Select a material that promotes

  In particular, as the surface resin layer 2, a (meth) acrylic equivalent of 100 to 300 g / eq, a hydroxyl value of 20 to 500, a polymer having a weight average molecular weight of 5,000 to 50,000 and a polyfunctional isocyanate, or a melting point of 40 ° C. or higher and a molecular weight of 5 Any of a mixture of an active energy ray-curable resin and a photoinitiator polymerization agent having a molecular weight of 1,000 to 100,000, or a glycidyl (meth) acrylate polymer obtained by addition reaction of an α, β-unsaturated monocarboxylic acid. The resin composition to be contained is preferable in that it has not only the above-mentioned properties but also a hard coat property with a pencil hardness of 3H or more after curing polymerization. The surface resin layer 2 may be colored or uncolored. As a method for forming the surface resin layer 2, there are coating methods such as a gravure coating method, a roll coating method, and a comma coating method.

Note that the state of unreacted curing polymerization does not mean that no curing polymerization has occurred, but does not mean that the main curing polymerization reaction has occurred, and includes cases in which a slight curing polymerization reaction has occurred. Also, the tack-free state to the touch with a finger with a top surface at a pressure of 1g heavy / cm ^2, refers to a condition in which the surface resin layer 2 does not stick on visually finger.

  The surface resin layer 2 is preferably formed to a thickness of 0.5 to 50 μm. This is because if the thickness of the surface resin layer 2 is less than 0.5 μm, the hard coat property and chemical resistance tend to be insufficient, and if the thickness of the surface resin layer 2 exceeds 50 μm, the productivity decreases.

  Next, a method for forming a large number of fine irregularities 5 on a part or all of the surface resin layer 2 by using a nanoimprint method on the surface resin layer 2 will be described. The nanoimprint method is a processing method in which a stamper is pressed against the surface resin layer 2 to form fine uneven portions 5 on the surface resin layer 2. Typical examples of the nanoimprint method include a thermal nanoimprint method, an optical nanoimprint method, and a room temperature nanoimprint method. In the present invention, fine irregularities 5 are formed on the surface resin layer 2 by a room temperature nanoimprint method or a thermal nanoimprint method at a low temperature. This eliminates the need for a process such as cooling, improves the throughput, and improves the dimensional accuracy.

  As a method of nanoimprinting, a stamper made of nickel electroforming is first produced from a master mold drawn with an electron beam, etc., then placed on the surface resin layer 2 and pressed under high pressure, and the stamper is placed on the surface. It removes from the resin layer 2 and forms the fine uneven | corrugated | grooved part 5 in the surface resin layer 2 (refer Fig.1 (a) and FIG.4 (a)). Moreover, the temperature at the time of pressing is set to normal temperature or 60 degrees C or less, and a pressure is generally set to several MPa. After pressing the stamper under the conditions, the stamper is removed from the surface resin layer 2 and the ionizing radiation 25 is irradiated to the fine irregularities 5 formed on the surface resin layer 2 (FIGS. 1B and 4B). )reference). By this irradiation, the curing polymerization reaction of the surface resin layer 2 that has not undergone the curing polymerization reaction is started, and the tough hard coat property / chemical resistance surface resin layer 2 is formed.

  Examples of the ionizing radiation 25 include radio waves, visible rays, ultraviolet rays, infrared rays, X-rays, gamma rays, particle rays, and electron beams.

  Examples of the surface shape of a large number of fine irregularities 5 include lines, polygons, circles, or combinations of these. Further, examples of the cross-sectional shape include U-shaped, V-shaped, and U-shaped uneven shapes (see FIGS. 5A to 5C). Among them, if a structure in which a large number of irregular pyramids or conical pyramids with a pitch of 10 to 50 μm and a depth of about 1 μm are arranged in an orderly manner, a mat-like high-quality design is exhibited. Preferred (see FIG. 6). A shape called a moth-eye structure (see FIG. 7) in which a large number of pyramids or conical pillars are regularly and regularly arranged with a pitch of 100 to 400 nm is preferable because it has an antireflection function. However, the surface shape of these many fine irregularities 5 is not limited to the above example.

  As a method for providing a large number of fine irregularities 5 at a desired position of the surface resin layer 2, a pattern for position detection different from the pattern is previously provided on the base sheet 1 by the pattern layer 3. A method of reading this pattern with a photoelectric tube or the like and determining the positional relationship between the pattern and a large number of fine irregularities 5 can be mentioned.

  The transfer sheet 30 has a configuration in which a release layer 9 is formed on the base sheet 1 as necessary, and the surface resin layer 2 and the pattern layer 3 are sequentially laminated on the base sheet 1 or the release layer 9 (FIG. 3 (a)).

  The release layer 9 formed as necessary is released from the surface resin layer 2 together with the base sheet 1 when the base sheet 1 is peeled off after transfer. As a material of the release layer 9, melamine resin release agent, silicone resin release agent, fluororesin release agent, cellulose derivative release agent, urea resin release agent, polyolefin resin release agent Paraffin type release agents and composite release agents thereof can 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.

  The pattern layer 3 is a layer for decorating various patterns and characters, etc., and the material is polyvinyl resin, polyamide resin, polyester resin, acrylic resin, polyurethane resin, polyvinyl acetal resin, A colored ink containing a resin such as a polyester urethane resin, a cellulose ester resin, or an alkyd resin as a binder and an appropriate color pigment or dye as a colorant may be used. As a method for forming the print layer, a normal printing method such as a gravure printing method, a screen printing method, or an offset printing method may be used. In particular, the offset printing method and the gravure printing method are suitable for performing multicolor printing and gradation expression. In the case of a single color, a coating method such as a gravure coating method, a roll coating method, or a comma coating method may be employed. The pattern layer may be provided in an arbitrary pattern depending on the pattern to be expressed. Further, if necessary, the metal film layer may be formed by a vacuum deposition method, a sputtering method, an ion plating method, a plating method, or the like. The metal film layer uses a metal such as aluminum, tin, nickel, gold, platinum, chromium, iron, copper, indium, silver, titanium, lead, zinc, or an alloy or compound thereof depending on the transparent color to be expressed. .

  In order to improve the adhesion between the pattern layer 3 and the surface resin layer 2, an anchor layer 11 may be provided. As the material of the anchor layer 11, two-component cured urethane resin, thermosetting urethane resin, melamine resin, cellulose ester resin, chlorine-containing rubber resin, chlorine-containing vinyl resin, acrylic resin, epoxy resin, vinyl A copolymer resin may be used. Examples of the method for forming the anchor layer 11 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.

  Moreover, you may form the contact bonding layer 12 on the pattern layer 3 entirely or partially as needed. The adhesive layer 12 adheres each of the above layers to the surface of the object to be decorated. Further, the adhesive layer 12 is formed in a portion to be bonded. That is, when the part to be bonded is the entire surface, the adhesive layer 12 is formed on the entire surface. If the part to be bonded is partial, the adhesive layer 12 is partially formed. As the adhesive layer 12, a heat-sensitive or pressure-sensitive resin suitable for the material to be decorated is appropriately used. For example, when the material of the object to be decorated is an acrylic resin, an acrylic resin may be used. In addition, when the material of the object to be decorated is polyphenylene oxide / polystyrene resin, polycarbonate resin, styrene copolymer resin, or polystyrene blend resin, acrylic resin, polystyrene resin, polyamide having affinity with these resins A series resin or the like may be used. Furthermore, when the material of the object to be decorated is a polypropylene resin, a chlorinated polyolefin resin, a chlorinated ethylene-vinyl acetate copolymer resin, a cyclized rubber, or a coumarone indene resin can be used. Examples of the method for forming the adhesive layer 12 include a coating method such as a gravure coating method, a roll coating method, and a comma coating method, a printing method such as a gravure printing method, and a screen printing method.

  Using the transfer sheet 30 configured as described above, the surface resin layer 2 and the pattern layer 3 can be transferred to the surface of the molded sheet 35 to produce a decorative molded sheet 110 (FIG. 3A). To (c)).

  A polyester resin film having a thickness of 38 μm was used as a molded sheet, and after a pattern layer having a predetermined pattern was provided on the molded sheet, a (meth) acryl equivalent of 100 to 300 g / eq, a hydroxyl value of 20 to 500, and a weight average molecular weight of 5 A surface resin layer composed of a polymer of 1,000 to 50,000 and a polyfunctional isocyanate was provided on the entire surface with a thickness of 10 μm to produce a decorative molded sheet. Next, a nanoimprint mold in which a large number of irregular pyramids or conical pyramids with a pitch of 10 to 50 μm and a depth of about 1 μm are regularly arranged is pressed on a part of the surface resin layer of the decorative molded sheet. After forming a fine uneven part and separating the nanoimprint mold from the surface resin layer, the fine uneven part of the surface resin layer was irradiated with ultraviolet rays.

  The decorative molded sheet after irradiating with ultraviolet rays exhibited a design with a matte high-class feeling in which the pattern layer and the fine uneven portions of the surface resin layer were in harmony. The surface resin layer had a very hard coating property with a pencil hardness of 5H.

  A surface resin layer comprising a melamine resin-based release layer and an addition reaction of α, β-unsaturated monocarboxylic acid on a 38 μm-thick polyester resin film as a base sheet. Is prepared on the entire surface of a molded sheet made of acrylic resin having a thickness of 100 μm, and a transfer sheet provided with a pattern layer made of acrylic resin and an adhesive layer made of urethane resin thereon is prepared separately. Then, after standing for 1 day, the base sheet was peeled off, and the surface resin layer, the pattern layer, and the adhesive layer of the transfer sheet were laminated and transferred to the surface of the molded sheet to produce a decorative molded sheet. Next, press the nanoimprint mold in which a large number of irregular cone-shaped pyramid shapes with a pitch of 10 to 50 μm and a depth of about 1 μm are arranged on the surface resin layer of the decorative molded sheet to form fine protrusions. After the formation and separation of the nanoimprint mold from the surface resin layer, ultraviolet rays were irradiated to fine convex portions of the surface resin layer.

  The decorative molded sheet after irradiating with ultraviolet rays exhibited a design with a matte high-class feeling in which the pattern layer and the fine uneven portions of the surface resin layer were in harmony. The surface resin layer had a very good hard coat property with a pencil hardness of 4H.

  A polyester resin film having a thickness of 38 μm is used as a base sheet, a melamine resin-based release layer, an active energy ray-curable resin having a melting point of 40 ° C. or higher and a molecular weight of 5,000 to 50,000, and a photoinitiator polymerization A transfer sheet provided with a surface resin layer made of a mixture and an image layer made of an acrylic resin and an adhesive layer on the surface resin layer is separately prepared and laminated on the surface of a molded sheet made of an acrylic resin having a thickness of 100 μm. After pressing with a 200 ° C. rubber roll moving at a speed of minutes, the base sheet was peeled off, and the surface resin layer, the pattern layer, and the adhesive layer of the transfer sheet were transferred to the surface of the molded sheet to produce a decorative molded sheet. Next, a nano-imprint mold having a structure in which a large number of square pyramid pillars are regularly and regularly arranged on the surface resin layer of the decorative molded sheet is pressed to form fine irregularities, and the nano-imprint mold After the mold was pulled away from the surface resin layer, ultraviolet rays were applied to the fine irregularities of the surface resin layer.

  The decorative molded sheet after irradiation with ultraviolet rays exhibited a design having an antireflection function in which the pattern layer and the fine uneven portions of the surface resin layer were in harmony. The surface resin layer had a very hard coating property with a pencil hardness of 5H.

  The present invention can be suitably used in various molded products such as communication devices such as mobile phones, electronic information devices, liquid crystal displays, and solar cells, and is industrially useful.

It is sectional drawing which shows the process of irradiating a nanoimprint process and an ionizing radiation among the manufacturing methods of the decoration molded sheet which concerns on this invention. It is sectional drawing which shows the process of providing a surface resin layer etc. on a base | substrate sheet | seat among the manufacturing methods of the decorative molded sheet which concerns on this invention. It is sectional drawing which shows another process of providing a surface resin layer etc. on a base sheet among the manufacturing methods of the decorative molded sheet which concerns on this invention. It is sectional drawing which shows the process of irradiating a nanoimprint process and an ionizing radiation among the manufacturing methods of the decoration molded sheet which concerns on this invention. It is a cross-sectional shape of the fine uneven | corrugated | grooved part of the surface resin layer in the decorative molded sheet obtained by the manufacturing method of the decorative molded sheet which concerns on this invention. It is the schematic of the fine uneven | corrugated | grooved part of the surface resin layer in the decorative molded sheet obtained by the manufacturing method of the decorative molded sheet which concerns on this invention. It is another schematic diagram of the fine unevenness | corrugation part of the surface resin layer in the decoration molding sheet obtained by the manufacturing method of the decoration molding sheet which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base sheet 2 Surface resin layer 3 Picture layer 5 Fine uneven part 9 Release layer 11 Anchor layer 12 Adhesive layer 20 Nanoimprint metal mold 25 Ionizing radiation 30 Transfer sheet 35 Molded sheet 110 Decorated molded sheet

Claims (7)

  After producing a decorative molded sheet having a surface resin layer formed on at least the outermost surface of the molded sheet, a nanoimprint mold is pressed on the surface resin layer to form minute irregularities, and the nanoimprint mold is formed on the surface resin layer. A method for producing a decorative molded sheet, comprising: irradiating ionizing radiation to the surface resin layer on which the fine irregularities are formed after being separated from the surface.   After forming at least a surface resin layer on the base sheet, transferring the surface resin layer to the surface of the molded sheet, peeling the base sheet, and producing a decorative molded sheet with the surface resin layer formed on the outermost surface Pressing the nanoimprint mold on the surface resin layer of the decorative molded sheet, separating the nanoimprint mold from the surface resin layer, and then irradiating the surface resin layer on which the micro unevenness is formed with ionizing radiation. A method for producing a decorative molded sheet.   When the nano-imprint mold is pressed on the surface resin layer to form minute irregularities, it is in a state that is not cured and unreacted and is tack-free, and the curing polymerization reaction is accelerated by irradiation with ionizing radiation. The manufacturing method of the decorative molded sheet in any one of Claims 1-2.   The decorative molded sheet manufactured with the manufacturing method of the decorative molded sheet in any one of the said Claims 1-3.   The surface resin layer has a (meth) acryl equivalent of 100 to 300 g / eq, a hydroxyl value of 20 to 500, a polymer having a weight average molecular weight of 5,000 to 50,000 and a polyfunctional isocyanate, or a melting point of 40 ° C. or higher and a molecular weight of 5,000. A resin comprising any one of a mixture of an active energy ray-curable resin and a photoinitiator polymer, which is ˜100,000, or a glycidyl (meth) acrylate polymer obtained by addition reaction of an α, β-unsaturated monocarboxylic acid The decorative molded sheet according to claim 4, comprising a composition.   The decorative molded sheet according to any one of claims 4 and 5, wherein the minute unevenness formed on the surface resin layer is a mat.   The decorative molded sheet according to any one of claims 4 and 5, wherein the minute unevenness formed on the surface resin layer has a low reflection moth-eye structure.

Images