JPH02266975A - In-mold transfer sheet and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an in-mold transfer sheet.

[Conventional technology and Problems that the invention seeks to solve]

Transfer sheets are made by laminating a transfer layer with a decorative pattern such as a picture pattern or a metal thin film pattern on a base film that has mold releasability, and these transfer layers are transferred to the transferred product to create a pattern or metallic luster. It is widely used for the purpose of manufacturing products with patterns. Furthermore, transfer sheets are also used in which an uneven pattern is formed on the surface of the base film or the release layer for the purpose of improving the design of the product by forming an uneven pattern on the surface of the transfer layer after transfer.

Conventional transfer sheets of this type have a base film made of a material with excellent mold releasability, such as a polyester film, or a material that has been coated on the surface of the base film for the purpose of improving mold releasability.
■Those with a release layer formed of wax, fatty acid amide, silicone, etc. (Japanese Unexamined Patent Publication No. 63-22697), ■
A mold release layer is formed by coating a thermosetting resin on a base material and curing it (Japanese Unexamined Patent Publication No. 61-53098, Utility Model Application No. 62
-29234) etc. are known.

In this type of transfer sheet, the releasability of the base material must not be too low, but it must also not be too high.
It must have appropriate adhesive strength and releasability to the transfer layer. That is, when the releasability is too high (releasing is too light) such that the base material is easily peeled off before the base material is peeled off after transfer, or when printing is applied to the transfer layer, for example,
When performing so-called in-mold transfer, in which the transfer layer is transferred to the injection molded product by loading the transfer sheet into an injection mold and injecting the resin, and then peeling off the base material, the heat during printing and the injection molding It is undesirable to use a transfer sheet that reduces the peelability between the base material and the transfer layer due to heat during transfer, making it difficult to peel off the base material after transfer (peeling becomes difficult). Because the transfer layer may be stored for a long period of time before being used, it is desirable that the releasability of the transfer layer remains constant over time. However, transfer sheets with a release layer as described in There is a possibility that the release layer will melt due to the heat generated during printing, etc. or in-mold molding, and the peel strength will change. In sheets, the base material tends to shrink and become distorted due to the heating that occurs when curing the resin during the process of forming the release layer.For this reason, heating during the curing process should be suppressed as much as possible (reducing heating time, heating temperature, etc.). ) However, if heating is suppressed, there is a problem that curing will be insufficient and the transfer layer will peel off too easily.Also, by suppressing heating during curing, the resin constituting the release layer will If it is in an uncured state, the curing reaction of the release layer will be accelerated by the heat when printing on the transfer layer or the heat during in-mold molding, making it extremely difficult to peel off the release layer. There is a drawback that the peel strength tends to fluctuate, such as the peel strength becoming difficult to peel over time during storage.

On the other hand, in order to form an uneven pattern on the surface of the base film in this transfer sheet, there are two methods: (a) heating and pressing a general embossing plate onto the base film to directly imprint the uneven shape on the surface; (b) A method is known in which a concavo-convex pattern is provided on a base film by raised printing. However, in the case of (a) above, when a polyester film with good mold releasability and surface properties is used as the film base material, or when an ionizing radiation-curable resin or a thermosetting resin is coated and cured, heat-resistant If a film with a certain release layer is used, it will not be possible to form a sharp uneven shape, and conversely, with a base film that is well shaped by the embossing plate mentioned above, there will be various difficulties in physical properties during actual use. For example, a base material such as polyvinyl chloride film has poor mold release properties, and a base material with a mold release layer as described in (2) on a polyester film cannot be used in in-mold transfer exposed to high temperatures. ,
There is a drawback that the uneven shape is destroyed and a good uneven pattern cannot be transferred. Furthermore, in this method, the formation of the uneven pattern and the formation of the pattern are performed in separate processes using different processing machines, so it is difficult to synchronize the uneven pattern with the pattern on the transfer layer, and the uneven pattern is applied only to the necessary areas. That was difficult. Furthermore, the above method (b) has the disadvantage that the liquid ink transferred from the plate onto the film substrate flows, making it difficult to print and form sharp and fine embossed shapes.

[Means to solve the problem]

The present invention has been made in view of the above points, and an object of the present invention is to provide an in-mold transfer sheet that eliminates the drawbacks of the prior art.

That is, the present invention has the following features: (1) An ionizing radiation curable resin is supplied between a roll intaglio having an uneven surface and a base film, and the base film is brought into contact with the roll intaglio, so that the roll intaglio is in contact with the base film. During the process, ionizing radiation is irradiated to harden the ionizing radiation-curable resin, and the uneven pattern-forming surface of the base film is provided with an uneven pattern made of the ionizing radiation-curable resin corresponding to the unevenness of the rolled intaglio plate. An in-mold transfer sheet comprising a laminated transfer layer having a decorative layer.

(2) The concavo-convex pattern made of ionizing radiation-curable resin consists of a group of straight or curved parallel grooves with different groove direction angles in adjacent partitioned areas and with a groove width, pitch, and depth of 0.1 to 100μ. The in-mold transfer sheet according to claim 1, wherein the in-mold transfer sheet is composed of an aggregate of a plurality of divided areas.

(3) An in-mold transfer sheet characterized by processing the following steps (a) and (b) in this order and in-line while passing the base film between the paper feed section and the paper discharge section of the same printing machine. manufacturing method.

(a) An ionizing radiation-curable resin is supplied between a roll intaglio plate having an uneven surface and a base film, and the base film is brought into contact with the roll intaglio plate, and while the roll intaglio plate is in contact with the base film, ionization occurs. The ionizing radiation-curable resin is cured by irradiation with radiation, and a concavo-convex pattern made of the ionizing radiation-curable resin corresponding to the concave-convex portions of the roll intaglio is formed on the surface of the base material, and then the surface of the base material on the side where the concave-convex pattern is formed is A decorative layer is provided by printing.

The main points are as follows.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of the transfer sheet 1 of the present invention, in which the transfer sheet 1 is partially peeled on the release layer 3 side of a base film 4 on which a release layer 3 having an uneven pattern 2 is formed. providing layer 5;
After forming a picture pattern 6 on the surface of this peeling layer 5 at a position corresponding to the uneven pattern 2 and further forming a vapor deposition stable layer 7,
It has a structure in which a metal vapor deposit 118 is formed and an adhesive 19 is laminated on the surface of the metal vapor deposit layer 8.

The base film 4 has moldability (flexibility, etc.) required for in-mold transfer, heat during in-mold transfer,
If ionizing radiation is to be irradiated from the base film side, select a material that has enough heat resistance to prevent deformation, swelling, etc., and is transparent to the ionizing radiation used. For example, polyethylene terephthalate. , polyesters such as polybutylene terephthalate, low crystalline polyesters such as polyethylene terephthalate/isophthalate copolymers, polycarbonates, polyimides, polyarylates, polyether ether ketones, cellulose acetate, polyvinyl chloride, polyamides (e.g. 6-nylon, 6.6-
nylon, etc.), vinylon, and polyolefins such as polyethylene, polypropylene, and polymethylpentene, or laminates thereof, and particularly preferred are polyethylene terephthalate, polyarylate, polyether ether ketone, polyimide, etc., which have high heat resistance.

The thickness of the base film 4 is usually 5 to 200 μm, preferably 12 to 50 μm. Further, the side of the base film 4 on which the release layer 3 is to be formed may be subjected to an adhesion-facilitating treatment such as a corona discharge treatment, if necessary.

The ionizing radiation-curable resin constituting the mold release N3 having the uneven pattern 2 includes ionizing radiation-curable polymers, oligomers, monomers alone or mixtures thereof, or ionizing radiation-curable polymers, oligomers, and monomers of these. A mixture of at least one kind and an ionizing radiation non-curable resin can be used.

In the present invention, the uneven pattern 2 is as shown in FIG.
The base film 4 is supplied so as to pass between a roll intaglio 10 having an uneven pattern 2a on its surface and a press roll 11, and an ionizing radiation-curable resin 12 is applied between the roll intaglio 10 and the press roll 11. At the same time, the base film 4 is brought into contact with the rolled intaglio plate 10, and while the intaglio plate 10 is in contact with the base film 4, ionizing radiation is irradiated from the ionizing radiation irradiation device 13 to cure the ionizing radiation-curable resin. It can be formed by Although not particularly shown, the base film 4, whose surface has been previously coated with an ionizing radiation-curable resin, is passed between the roll intaglio 1O and the press roll 11 to bring the base film 4 into contact with the roll intaglio 1O. The uneven pattern 2 can also be formed by a method of irradiating ionizing radiation from the ionizing radiation irradiation device 13 while the resin 10 is in contact with the base film 4 to harden the ionizing radiation-curable resin. In the latter method, the base film 4
Before the base film 4 coated with the ionizing radiation curable resin is passed between the intaglio 10 and the press roll 11, in order to suppress the fluidity of the ionizing radiation curable resin to a certain extent so that the ionizing radiation curable resin coated on the ionizing radiation curable resin does not flow. The resin is semi-cured by irradiating it with an appropriate amount of ionizing radiation, or if necessary, it is passed through a drying device for drying and removing the diluting solvent in the ionizing radiation-curable resin. Good too. It should be noted that the base film 4 may be provided with a release layer in advance, or a base film made of a resin with high release properties. In this case, the roll intaglio plate 1 may be used in the method shown in FIG.
It is also possible to form only the uneven pattern 2 on the releasable surface by filling only the recessed portions of the ionizing radiation curable resin 12 with the ionizing radiation curable resin 12. The ionizing radiation irradiation device 13 may be provided inside the roll intaglio plate 10 to irradiate the ionizing radiation from inside the roll intaglio plate 10. In this case, the base film 4 may be one that does not transmit ionizing radiation.

As the ionizing radiation, for example, ultraviolet rays, electron beams, etc. can be used.

The roll intaglio plate 10 used has recesses formed by electronic engraving, etching, mill extrusion, electroforming, or the like. The pattern of the concavo-convex pattern 2a in the intaglio plate 10, as shown in FIG. is 0.1 to 1100a, and the groove direction angles are preferably different in each adjacent divided region 14. It is preferable that the groove direction angle in the adjacent section KSM region 14 is 5 degrees or more, and furthermore, it is preferable that the groove direction angles are all different in all the adjacent section regions 14,
In order to do this, it is necessary to have four or more types of groove directions based on the "four-color problem theorem" of topology. Since the concavo-convex pattern of such a pattern changes the gloss of each divided area variously depending on the parallax, the design of the product is further enhanced.

The peeling layer 5 provided on the release layer 3 side of the base film 4 on which the uneven pattern 2 is formed as described above has the function of protecting the surface of the transfer layer after transfer.

The peeling J! 15 can be formed from acrylic resins such as polymethyl methacrylate, polybutyl methacrylate, and polyethyl methacrylate, vinyl chloride-vinyl acetate copolymers, polyurethane, epoxy resins, cellulose resins, etc. alone or in mixtures thereof. However, acrylic resins are particularly preferred because they have transparency, scratch resistance, abrasion resistance, and processability, and the surface properties of the molded product after in-mold transfer are excellent. Strip it! 1W15 is formed by applying the above resin by a coach ink method such as gravure coating or roll coating, or a printing method such as screen printing or gravure printing. Further, the release layer 5 may contain wax, a matting agent, etc., if necessary.

The release layer 5 does not necessarily need to be provided when the transfer layer has excellent releasability and sufficient smoothness can be obtained on the surface of the transfer layer after transfer.

As shown in FIG. 2, the picture pattern 6 and the uneven pattern 2 are
FIG. 2 shows a case where a picture pattern 6 is formed immediately after the uneven pattern 2 is formed without providing a peeling layer 5. )
Formed in-line using a separate unit of the same printing machine. The pattern 6 is made of ordinary printing ink, preferably a release layer 5
A desired pattern can be printed using an ink using a resin equivalent to the above as a vehicle. Gravure printing, silk screen printing, offset printing, etc. are used as printing methods. Fig. 2 shows the case where a picture pattern 6 is formed by the gravure stamp side method, in which 16 is a plate cylinder, 17
18 indicates a doctor knife, 18 indicates an ink pan, and 19 indicates a dryer. The pattern 6 does not have to be provided in the same position as the uneven pattern 2 (it may be provided in a part where the uneven pattern 2 is not formed).
Also, it is not limited to the case where it is provided partially, but it may be provided on the entire surface (
, or may be provided by performing multiple overlapping printings.

The uneven pattern 2 and the printed picture pattern 6 are printed in register so that the relative positional relationship of the hero is always constant.

Vapor deposition stability N7 is provided to stabilize specularity and formability during in-mold molding of vapor deposition, for example -
It is formed from liquid or two-part polyurethane, polyamide, polyimide, polyester, melamine, etc.

The metal vapor deposition layer 8 is made of aluminum, chromium, nickel, copper,
It can be formed from metal such as zinc. Further, instead of the vapor deposition method, a method of laminating metal foil may be adopted, and furthermore, it is not limited to the case where it is provided on the entire surface, but it can also be provided in a desired pattern. When forming a desired pattern, a removal layer made of a water-soluble resin such as polyvinyl alcohol, cellulose resin, or starch is provided in advance on the part from which the vapor-deposited layer has been removed, and then a metal vapor-deposited layer is applied to the entire surface of this layer, and then washed with water to remove the water-soluble resin. Remove the vapor-deposited layer above the water-soluble resin together with the water-soluble resin, or provide a protective layer on the upper surface of the part that needs to be left as a partially vapor-deposited layer after vapor-depositing the entire surface.
Next, a method such as dissolving and removing unnecessary parts for vapor deposition using acid, alkali, etc. can be adopted.

The metal vapor deposition 18 does not necessarily need to be provided, and only the picture pattern layer 6 may be provided.

An adhesive layer 9 is provided on the uppermost surface side of the transfer layer (the surface in contact with the transferred object).
is provided. The adhesive layer 9 is made of acrylic resin, vinyl chloride resin, vinyl acetate resin, rubber resin, olefin resin,
A heat-fusion type resin made of a thermoplastic resin such as an epoxy resin, a urethane resin, or a mixture thereof, or a copolymer resin thereof can be used. The adhesive layer 9 is formed by applying the above-mentioned resin by a coating method such as gravure coating or roll coating, or by printing by gravure printing or silk screen printing, or by coating, spray painting, flow coating, etc. It can be formed by coating.

Note that this adhesive layer 9 can be used only when the adhesive force of the transfer layer is practically sufficient (
For example, in the case where the surface side of the transfer layer is a pattern printing layer formed using the same resin as the resin constituting the adhesive layer, etc.), it is not necessary to provide it.

Although the transfer sheet 1 of the present invention is suitable for use in in-mold transfer, it can also be used in other general transfer methods such as hot stamping. When transferring by in-mold transfer, the transfer sheet 1 of the present invention is loaded into an injection mold and injection molded so that the adhesive layer 9 is located on the injected resin side, and then the base film 4 is peeled off. By doing so, the transfer layer having the uneven pattern 2 can be transferred to the surface of the molded product 150 as shown in FIG.

Hereinafter, the present invention will be explained in more detail by giving specific examples.

Example 1 An i-adhesive polyethylene terephthalate film (manufactured by Kijin: HP-7,50IIm) was used as a base film, and the following ionizing radiation-curable resin and intaglio were used on the surface of the film, and ionizing radiation was irradiated under the following conditions. A release layer having an uneven pattern was formed.

・Ionizing radiation curable resin: UV curable resin (manufactured by Dainichiseika: Seikabeam HT5
09, viscosity 3000 cps)・Intaglio: Each divided area has lines with a groove width and plate depth of 15 μm and a pitch of 30 μm, and multiple divided areas are divided by changing the direction angle of the adjacent lines through the sides. An intaglio plate with a concave pattern consisting of aggregates. The angle of the line is 0@ (standard)
, 30", 60@, and 90°.

- Ionizing radiation irradiation conditions Ultraviolet rays were irradiated at a substrate feed rate of 1 m/sin using an irradiation device equipped with two high-pressure mercury lamps (80 W/cm) containing niosine.

Next, a release layer forming resin (Hakulinis 35T manufactured by Showa Ink Kogyo Co., Ltd.) was applied to the surface of this release layer using a gravure roll at a coating amount of 3 g/rrf to form a release 1111 layer. A picture pattern was printed on it by gravure printing.

Furthermore, an adhesive layer-forming resin (manufactured by Showa Ink Industries: H3ES-3) was applied to the surface with the pattern using a gravure roll at a coating amount of 3 g/rrr to form an adhesive layer. All steps up to the formation of zero or more release layers to the adhesive layer as a transfer sheet were performed in-line using each unit of the same printing machine.

This transfer sheet was loaded into an injection mold and then injection molded. After cooling, the molded product was taken out of the mold and the base material of the transfer sheet was peeled off. The peelability of the base material was good and the pattern was molded reliably. A molded product was obtained in which a transferred pattern with a beautiful uneven pattern was formed on the surface.

〔Effect of the invention〕

As explained above, in the transfer sheet of the present invention, an ionizing radiation-curable resin is supplied as a base film between the roll intaglio plate having an uneven surface and the base film, and the base film is brought into contact with the roll intaglio plate. While the intaglio was in contact with the base film, ionizing radiation was irradiated to harden the ionizing radiation-curable resin, and the surface was provided with irregularities and patterns made of the ionizing radiation-curable resin that corresponded to the irregularities of the rolled intaglio. Because it uses a film, it always exhibits almost constant removability,
There is no risk that the releasability will be significantly increased due to heat during printing after the transfer layer is formed, heat during transfer, etc. Further, unlike when the mold release layer is formed from a thermosetting resin, there is no need to harden the resin by heating, so there is no risk of the base film deforming or shrinking in the process of manufacturing the transfer sheet. Furthermore, according to the transfer sheet of the present invention, it is possible to form a sharp, fine, and beautiful uneven pattern, and the uneven pattern is not destroyed by the heat during in-mold transfer. It is possible to reliably form a pattern.Also, the uneven pattern can be formed from a group of straight or curved parallel grooves in which the groove direction angles are different in adjacent divided areas, and the groove width, pitch, and depth are 0.1 to 100μ. By employing a product consisting of an aggregate of a plurality of divided areas, it is possible to obtain a product with even higher design quality in which the gloss of each divided area changes variously depending on the parallax.Furthermore, according to the method of the present invention, the Since the uneven pattern and the printed pattern are formed in-line by separate units of the same printing machine, it is possible to accurately align the uneven pattern and the printed pattern.As a result, the uneven pattern on the transfer layer and the printed pattern can be accurately aligned. It is possible to obtain a transfer sheet with accurate relative positional relationship with the pattern.Moreover, since the uneven pattern and the printed pattern can be formed in the same process, the number of manufacturing steps is reduced compared to the conventional method in which both are performed in separate processes. This has the effect of improving productivity because manufacturing time can be shortened.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, FIG. 1 is a longitudinal cross-sectional view of one embodiment of the transfer sheet of the present invention, FIG. 2 is an explanatory diagram showing an example of the method for manufacturing the transfer sheet of the present invention, and FIG. FIG. 4 is a plan view showing an example of an uneven pattern, and a sectional view of a main part of a product transferred using the transfer sheet of the present invention. 1... Transfer sheet 2.2a... Uneven pattern 3...
・Release layer 4...Base film 6...Picture pattern 8
... Metal vapor deposition N10 ... Roll intaglio 12 ... Ionizing radiation curable resin 13 ... Ionizing radiation irradiation device 1
4...Divided area 16...Plate cylinder diagram diagram diagram diagram

Claims (3)

[Claims] (1) An ionizing radiation-curable resin is supplied between a roll intaglio plate having an uneven surface and a base film, and the base film is brought into contact with the roll intaglio plate, and while the roll intaglio plate is in contact with the base film, ionization occurs. A decorative layer is applied to the surface of the substrate film on the side where the uneven pattern is formed, which is made by irradiating the ionizing radiation curable resin to harden it and forming an uneven pattern made of the ionizing radiation curable resin on the surface that corresponds to the unevenness of the rolled intaglio plate. An in-mold transfer sheet characterized by being formed by laminating transfer layers having the following properties. (2) The concavo-convex pattern made of ionizing radiation-curable resin consists of a group of straight or curved parallel grooves with different groove direction angles in adjacent partitioned areas and with a groove width, pitch, and depth of 0.1 to 100μ. The in-mold transfer sheet according to claim 1, comprising an aggregate of a plurality of divided areas. (3) An in-mold transfer sheet characterized by processing the following steps (a) and (b) in this order and in-line while passing the base film between the paper feed section and the paper discharge section of the same printing machine. manufacturing method. (a) An ionizing radiation-curable resin is supplied between a roll intaglio plate having an uneven surface and a base film, and the base film is brought into contact with the roll intaglio plate, and while the roll intaglio plate is in contact with the base film, ionization occurs. The ionizing radiation-curable resin is cured by irradiation with radiation to provide a concavo-convex pattern made of the ionizing radiation-curable resin corresponding to the concave-convex portion of the roll intaglio on the surface of the base material; A decorative layer is provided by printing on the surface.