JP2011231254A - Method for producing embossing ink, partial matte hardcoat transfer sheet, and method for producing partial matte hardcoat molding - Google Patents

Abstract

When creating a partial mat hard coat transfer sheet using mat layer forming ink (hereinafter referred to as "embossed ink"), unnecessary ink formed on the plate cylinder cannot be completely removed with a doctor blade and transferred. This is a point where the sheet is soiled.
An embossing ink comprising a filler and a vehicle which are printed on a transfer sheet by gravure printing to form a mat shape. The filler has an oil absorption of 100 to 300 ml / 100 g, and the vehicle is a resin having an OH value of 70 mgKOH / g or less. 1 part by weight of vehicle and filler were mixed in an amount of 0.05 to 0.10 parts by weight.
[Selection] Figure 1

Description

  The present invention relates to an embossed ink used for forming a mat (matte) part by printing on a transfer sheet, and a partial mat hard coat used to obtain a molded article having a part of the mat and high surface strength. The present invention relates to a method for producing a transfer sheet and a partially mat hard coat molded article.

  As a transfer sheet for obtaining a decorative molded product having a high surface strength and a partially mat-shaped surface, a mat layer is partially formed on the substrate sheet by a gravure printing method, and a hard coat layer is formed thereon. Furthermore, there are those in which a pattern layer, an adhesive layer, and the like are formed thereon.

The partial mat layer is printed in the following steps (1) to (4). FIG. 2 is an explanatory diagram of the gravure printing method and will be described with reference to FIG.
(1) a process of copying the ink 22 from the ink tank 21 to the ink roller 23;
(2) a step of further copying the ink copied onto the ink roller 23 onto the plate cylinder 24;
(3) A step of removing unnecessary ink with the doctor blade 25 in order to keep the ink only on the concave portion formed on the plate cylinder among the ink copied to the plate cylinder 24;
(4) A step of printing on the base sheet 1 the ink formed in the concave portion of the plate cylinder.

  The mat layer imparts an uneven shape to the hard coat layer, and the ink forming the mat layer is a mixture of a filler and a vehicle.

  Conventional mat layer forming ink (hereinafter referred to as “embossed ink”) uses fine particles such as silica and alumina as a filler, and consists of an epoxy resin, a melamine resin, or a copolymer resin or a mixture thereof as a vehicle ( For example, see Patent Document 1). In particular, a mixture of silica particles as a filler and a mixture of an epoxymelamine resin and an aminoalkyd resin as a vehicle are frequently used.

  However, when a mat layer is partially formed on a base sheet by a gravure printing method using conventional ink, in the step (3), unnecessary ink formed on the plate cylinder cannot be completely removed with a doctor blade, and the mat layer There is a drawback that an extra mat layer (hereinafter referred to as “background stain” for the transfer sheet and “unnecessary mat layer” for the molded product) is formed other than the place intended to be formed. For this reason, there is a problem that the mat layer cannot be formed only at a desired position.

JP 2000-85299 A

  The problem to be solved is that unnecessary ink formed on the plate cylinder cannot be completely removed with a doctor blade. Also, the problem to be solved is that background stains occur on the partial mat hard coat transfer sheet. Furthermore, the problem to be solved is that, in a molded product produced by transferring a partial mat hard coat transfer sheet, the contrast between the matte part and the glossy part derived from the mat layer becomes unclear.

  Other problems of the present invention will become apparent from the description of the present invention.

  The inventors observed the conventional embossed ink and its printing behavior, and obtained the following knowledge.

  In the conventional embossed ink silica fine particles and the mixture of epoxy melamine resin and amino alkyd resin, the filler and vehicle are not uniformly dispersed. When the conventional embossed ink is stored at rest, the embossed ink is divided into an upper layer and a lower layer.

  Resin components gather in the upper supernatant, and a mixture of silica and resin gathers in the lower sedimentation. Furthermore, the silica and resin present in the sedimentation part are a gel-like mixture of silica and resin due to a large proportion of silica.

  When the gel-like mixture of silica and resin adheres to the plate cylinder, it is not completely removed by the doctor blade, and the ink that has not been removed is printed on the base sheet, causing soiling and unnecessary mat layers.

  Based on the above findings, the inventors have come up with means for solving the following problems.

The embossed ink according to one aspect of the present invention is
In embossing ink consisting of filler and vehicle, used for gravure printing on transfer sheet and used to give mat shape,
The filler has an oil absorption of 100 ml / 100 g or more and 300 ml / 100 g or less,
The vehicle is a resin having an OH value of 70 mgKOH / g or less,
1 part by weight of the vehicle and the filler are mixed in an amount of 0.05 parts by weight or more and 0.10 parts by weight or less.

In the embossing ink according to a preferred embodiment of the present invention,
The vehicle may be a mixture of epoxy melamine resin and acrylic resin.

In an embossing ink according to another preferred embodiment of the present invention,
The filler may be silica.

The partial mat hard coat transfer sheet according to another embodiment of the present invention is
In a partial mat hard coat transfer sheet in which at least a partial mat layer, a hard coat layer, and an adhesive layer are laminated on a substrate sheet having peelability,
The partial mat layer is formed by gravure printing using the embossed ink according to the present invention.

The method for producing a partial mat hard coat molded article according to another aspect of the present invention is as follows.
The partial mat hard coat transfer sheet according to the present invention is sandwiched in an injection mold, and a molding resin is injected into the cavity to obtain an injection molded product. At the same time, the partial mat hard coat transfer sheet is adhered to the surface. The injection molding die is opened, and the base sheet is peeled off together with the partial mat layer.

  The present invention described above, preferred embodiments of the present invention, and components included in these can be implemented in combination as much as possible.

  The embossed ink according to the present invention does not separate into two layers even if it is allowed to stand after mixing for reasons such as good compatibility between the filler and the vehicle. For this reason, a gel-like mixture of filler and vehicle does not occur. Therefore, when gravure printing is performed using the embossed ink according to the present invention, the matte layer is printed only in the intended region. Moreover, the embossing ink concerning this invention can increase the ratio of a filler. For this reason, an even more uneven mat layer can be formed.

  In the partial mat hard coat transfer sheet according to the present invention, no background stain is formed.

  According to the method for producing a partially matte hard coat molded product according to the present invention, a molded product having a clear contrast between the matte portion and the glossy portion can be obtained. Further, the molded product has an advantage that the mat feeling is uniform in the single mat area and between the plurality of mat areas, and the mat feeling is uniform.

FIG. 1 is an explanatory cross-sectional view of a partial mat hard coat transfer sheet. FIG. 2 is an explanatory diagram of the gravure printing method.

  Hereinafter, with reference to drawings, the manufacturing method of the embossed ink concerning the example of the present invention, a partial mat hard coat transfer sheet, and a partial mat hard coat molded article is further explained. In the drawings referred to in this specification, in order to facilitate the understanding of the present invention, some of the components are schematically illustrated in an exaggerated manner. For this reason, the dimension, ratio, etc. between components may differ from a real thing. Further, the dimensions, materials, shapes, relative positions, etc. of the members and parts described in the embodiments of the present invention are not intended to limit the scope of the present invention to those unless otherwise specified. It is merely an illustrative example.

  Embossed ink is composed of filler and vehicle. The filler forms a mat shape on the printing surface.

  The oil absorption amount of the filler is usually 100 ml / 100 g or more and 300 ml / 100 g or less, preferably 100 ml / 100 g or more and 250 ml / 100 g or less. Compared to the highly hydrophilic filler used in conventional embossed inks, a hydrophobic filler is used. Fillers include silica, alumina, titanium oxide, carbon black, precipitated barium, calcium carbonate, calcium oxide, talc and other inorganic pigment fine particles, phthalocyanine, dioxazine, anthraquinone organic pigment fine particles and resin beads. is there. Among these, silica can be preferably used. Silica has a constant particle size over time after mixing with the vehicle.

  Regarding the mixing ratio of the vehicle and the filler, the lower limit value of the filler mixing amount is 1 part by weight of the vehicle and 0.05 part by weight of the filler. The upper limit of the amount of filler mixed is 1 part by weight of the vehicle and 0.10 parts by weight of filler. In other words, 0.05 part by weight or more and 0.10 part by weight or less of 1 part by weight of the vehicle and filler are mixed. If it exists in this range, a filler will fully be mixed with a vehicle and sufficient mat | matte shape will be formed in a printing surface.

  In the conventional embossed ink, about 1 part by weight of the vehicle and about 0.05 part by weight of the filler are mixed. Even if the filler exceeding the said weight part was added, embossed ink did not become a uniform solution. On the other hand, the embossing ink according to the present invention can add up to 0.10 parts by weight of filler to 1 part by weight of the vehicle.

  The average particle diameter of silica as a filler is 3 μm to 8 μm. If it is in this range, a suitable mat shape can be formed.

  The vehicle is a resin having an OH value of 70 mgKOH / g or less. The lower limit of the OH value of the vehicle resin is usually 0 mgKOH / g. From the viewpoint of availability and other properties, it is preferably 5 mgKOH / g. Epoxymelamine and aminoalkyd resins used in conventional embossed inks have an OH value of about 80 mgKOH / g to 100 mgKOH / g.

  In this way, the vehicle was changed to a highly lipophilic resin to improve the compatibility with the filler. Here, the OH value is a value measured as a mixture in the case of a mixed resin, and is a value measured as a kind of resin in the case of a kind of resin.

  Specific examples of the vehicle include a mixture of an epoxy melamine resin and an acrylic resin, a mixture of an epoxy melamine resin and a polyester resin, a mixture of an epoxy melamine resin and a urethane resin, and a mixture of an epoxy melamine resin and an aminoalkyd resin.

  Next, a partial hard coat transfer sheet using embossed ink will be described.

  FIG. 1 is a cross-sectional explanatory view of a partial mat hard coat transfer sheet 100. The partial mat hard coat transfer sheet 100 includes a base sheet 1. One surface of the base sheet 1 has peelability. The surface having the peelability is a surface on which the partial mat layer 3 and the hard coat layer 4 are formed.

  The material of the base sheet 1 includes polypropylene resin, polyethylene resin, polyamide resin, polyester resin, acrylic resin, polyvinyl chloride resin resin sheet, aluminum foil, copper foil and other metal foil, glassine paper Cellulose-based sheets such as coated paper and cellophane, or composites of the above respective sheets can be used. In order to improve the peelability of the base sheet 1, a release layer may be provided on the surface of the base sheet 1. As the material of the release layer, melamine resin, silicone resin, fluorine resin, cellulose derivative, urea resin, polyolefin resin, paraffin resin, and composites thereof can be used. Examples of the method for forming the release layer include coating methods such as a roll coating method and a spray coating method, and printing methods such as a gravure printing method and a screen printing method.

  Next, the partial mat layer 3 is formed on one surface of the base sheet 1. The partial mat layer 3 is formed in contact with the surface of the base sheet 1. When a release layer is formed on the surface of the base sheet, the partial mat layer 3 is formed in contact with the release layer.

  After the transfer, the partial mat layer 3 is peeled off from the molded product together with the base sheet 1 to copy the mat shape of the partial mat layer 3, that is, a fine uneven shape onto a part of the hard coat layer 4.

  The partial mat layer 3 is formed by printing using the embossed ink according to the present invention. The printing method is a gravure printing method. However, a screen printing method or an offset printing method may be employed. Moreover, you may apply | coat by the coating method. For example, a bar coater can be used as the coater.

  The thickness of the partial mat layer 3 is usually 0.5 μm to 30 μm, more preferably 0.5 μm to 5 μm. Within this range, even if the base sheet 1 is stretched during simultaneous molding and transfer to a two-dimensional or three-dimensional shape, it is possible to prevent the partial mat layer 3 from being sheared, and to follow the stretch of the base sheet 1. This is because it is possible to prevent the partial mat layer 3 itself from being cracked.

  A hard coat layer 4 is entirely formed on the base sheet 1 or the partial mat layer 3. The hard coat layer 4 has a certain level of hardness, and is a layer that peels from the base sheet 1 and becomes the uppermost layer of the transfer layer when the base sheet 1 is peeled after transfer. The hard coat layer 4 is made of an active energy ray-curable resin that is cured by ultraviolet rays, electron beams, or the like typified by a photocurable resin such as an ultraviolet curable resin or a radiation curable resin such as an electron beam curable resin.

  The hard coat layer 4 may be a thermosetting and active energy ray curable resin. The active energy ray curable resin is, for example, a urethane acrylate resin or a cyanoacrylate resin. The thermosetting and active energy ray-curable resin is, for example, a resin obtained by adding an additive such as isocyanate to a urethane acrylate resin or a cyanoacrylate resin. When the thermosetting and active energy ray-curable resin is heated, some of the monomers and oligomers in the resin are cross-linked and become a semi-cured state. The semi-hardened hard coat layer is cured by further irradiating active energy rays such as ultraviolet rays.

  The hard coat layer 4 is formed by a gravure printing method or a liquid coating method. Examples of the liquid coating method include a gravure coating method, a roll coating method, a comma coating method, and a lip coating method. The thickness of the hard coat layer 4 is usually 2 μm or more and 40 μm or less, and more preferably 2 μm or more and 10 μm or less. When the thickness is within the above range, the surface of the resin molded product obtained by using the partial mat hard coat transfer sheet 100 prepared by the production method of the present invention has an excellent surface hardness since the thick hard coat layer is transferred. It can be.

  When a thermosetting and active energy ray-curable resin is selected as the hard coat layer 4, the hard coat layer is formed and then heated to a semi-cured state.

  The design layer 9 may be formed on the hard coat layer. The design layer 9 may not be provided. The design layer 9 is formed on the entire surface or a part of the surface of the hard coat layer 4. The design layer 9 is made of a suitable resin such as polyvinyl resin, polyamide resin, polyacrylic resin, polyurethane resin, polyvinyl acetal resin, polyester urethane resin, cellulose ester resin, alkyd resin, and the like. Colored inks containing color pigments or dyes as colorants may be used.

  As a method for forming the pattern layer 9, a normal printing method such as an offset printing method, a gravure printing method, or a screen printing method may be used. The pattern layer 9 may be made of a metal thin film or a combination of a printed film and a metal thin film. The metal thin film is formed by a vacuum deposition method, a sputtering method, an ion plating method, a plating method, or the like.

  The adhesive layer 5 may be formed on the design layer 9 as necessary. The adhesive layer 5 adheres each of the above layers to the surface to be decorated. As the adhesive layer 5, a heat-sensitive or pressure-sensitive resin suitable for the material to be decorated is used as appropriate. Examples of the method for forming the adhesive layer 5 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.

  Moreover, you may form the anchor layer which improves the interlayer adhesiveness of each layer between the design layer 9 and the hard-coat layer 4, and between the design layer 9 and the contact bonding layer 5, as needed.

  An example of the manufacturing process of the simultaneous molding product using the partial mat hard coat transfer sheet 100 will be described.

  For the production, an injection mold comprising an A mold and a B mold is used. The A mold and the B mold are opened, and the partial mat hard coat transfer sheet 100 is fed between them. The A mold and the B mold are clamped, and the molten resin is injected into the cavity. The adhesive layer 5 and the hard coat layer 4 are transferred to the molten resin side by pressure heat resulting from the injection of the molten resin.

  Thereafter, when cooled or allowed to cool naturally, the molten resin solidifies into a solidified resin, and an intermediate molded product is produced. Next, the base sheet 1 is removed from the intermediate molded product. At this time, the partial mat layer 3 is also removed while adhering to the base sheet 1.

Next, the hard coat layer 4 is crosslinked and cured by irradiation with active energy rays. It is good to irradiate on the conditions of about 400-4000 mJ / cm < ² > using an ultraviolet-ray etc. as an active energy ray. In this way, a hard coat resin molded product is obtained. A partial area of the hard coat layer transferred to the surface and cured is a matte area.

  The partial mat hard coat transfer sheet may be transferred onto the surface of the transfer object using a roll transfer machine, an up-down transfer machine or the like.

  A partial mat hard coat transfer sheet was prepared using embossed ink.

  The prepared partial mat hard coat transfer sheet is obtained by forming a release layer, a partial mat layer, a hard coat layer, a design layer, and an adhesive layer on one surface of a base sheet.

  A release layer is printed on the entire surface by a gravure printing method on one side of a biaxially stretched polyethylene terephthalate film having a thickness of 340 mm × 600 mm and a thickness of 38 μm, and then a part of embossing ink is printed by a gravure printing method. Formed. The number of mat layer regions was 50, and the total area of the mat layer regions accounted for 95% of the total area of the base sheet.

  Next, heat treatment was performed at 160 ° C. for 30 seconds. Subsequently, a hard coat layer having a thickness of 12 μm was formed by a bar coater # 16, and heat treatment was performed at 150 ° C. for 30 seconds. Next, an anchor layer, a pattern layer, and an adhesive layer were formed in this order by a bar coating method to obtain a partial mat hard coat transfer sheet. When the molding was simultaneously transferred using the obtained transfer sheet, a molded product having a partially matte tone was obtained.

  The details of the embossed ink according to Examples 1 to 6 and Comparative Examples 1 to 4 are shown in Table 1. In Examples 1 to 6 and Comparative Examples 1 to 4, silica was used as the filler.

  After adding silica to each vehicle, the mixture was stirred with a stirrer for 10 minutes and then left for 1 week. After standing, the dispersibility of the embossed ink was evaluated.

Dispersibility is
○ Vehicle and silica are not separated
△ Only silica settles
X The gel of vehicle and silica was evaluated in three stages of sedimentation.

  Moreover, the background stain | pollution | contamination of the partial mat | matte hard-coat transfer sheet produced using each embossing ink was evaluated. In the evaluation, white light using a fluorescent lamp was irradiated from the base sheet side, and the presence or absence of soiling was visually observed from a distance of 30 cm.

The dirt is
○ No dirt on the transfer sheet
△ There is a slight dirt on the transfer sheet.
X Evaluation was made on a three-point scale, where the transfer sheet was confirmed to be soiled.

  Furthermore, the gloss unevenness of the partial mat hard coat transfer sheet prepared using each embossed ink was evaluated. The evaluation was performed by irradiating white light using a fluorescent lamp from the base sheet side and visually checking for uneven gloss from a distance of 20 cm.

Uneven gloss
○ No gloss unevenness in 50 locations
△ Five or less gloss irregularities were confirmed in 50 locations.
X Evaluation was made in three stages, in which at least six gloss irregularities were confirmed in 50 locations.

Table 1 shows the results.

  In Table 1, EPM represents an epoxy melamine resin, and AmAlk represents an aminoalkyd resin. The filler mixing amount indicates the filler mixed with 1 part by weight of the vehicle in parts by weight. Furthermore, the average particle diameter is the average particle diameter of silica as a filler.

  In Examples 1 to 6, especially 1 to 5, the dispersibility of the embossed ink is good, and no soiling is confirmed on the partial mat hard coat transfer sheet prepared using the embossed ink. Not observed.

  Further, in the molded product prepared using the transfer sheet, no unnecessary mat layer was confirmed, and there was no uneven gloss between the mat layers.

DESCRIPTION OF SYMBOLS 1 Substrate sheet 3 Partial mat layer 4 Hard coat layer 5 Adhesive layer 9 Pattern layer 21 Ink tank 22 Ink 23 Ink roller 24 Plate cylinder 25 Doctor blade 100 Partial mat hard coat transfer sheet

Claims (5)

In embossing ink consisting of filler and vehicle, used for gravure printing on transfer sheet and used to give mat shape,
The filler has an oil absorption of 100 ml / 100 g or more and 300 ml / 100 g or less,
The vehicle is a resin having an OH value of 70 mgKOH / g or less,
Embossed ink, wherein 1 part by weight of the vehicle and the filler are mixed in an amount of 0.05 to 0.10 parts by weight.   The embossed ink according to claim 1, wherein the vehicle is a mixture of an epoxy melamine resin and an acrylic resin.   The embossed ink according to claim 1, wherein the filler is silica. In a partial mat hard coat transfer sheet in which at least a partial mat layer, a hard coat layer, and an adhesive layer are laminated on a substrate sheet having peelability,
The partial mat hard coat transfer sheet is formed by gravure printing using the embossed ink according to any one of claims 1 to 3.   The partial mat hard coat transfer sheet according to claim 4 is sandwiched in an injection mold, and a molding resin in a molten state is injected into a cavity to obtain an injection molded product. A method for producing a partially matted hard coat molded product, wherein a transfer sheet is bonded, the injection mold is opened, and the base sheet is peeled off together with the partially matted layer.

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