JP7524579B2 - Decorative film and decorative molded body - Google Patents

Description

The present invention relates to a decorative film and a decorative molded body.

Conventionally, when protecting or decorating the surfaces of automobile interior and exterior parts, home appliance parts, building material parts, etc., a molded body is processed by injection molding or vacuum forming, and then paint is applied to the surface of the molded body by spray painting or the like, and then dried and cured by heating. However, this type of painting has problems such as the emission of volatile organic solvents that worsens the work environment, the need for separate work processes and production equipment for each molded part, and the need to apply multiple coats of paint, which results in poor paint yield and low productivity.

In recent years, resin molded bodies have been increasingly used as molded bodies for the purpose of reducing the weight of automobile interior and exterior parts, home appliance parts, building material parts, etc. Spray painting is often not suitable for decorating resin molded bodies, and various methods have been developed to decorate the surface of resin molded bodies. Among these, the method of obtaining a decorated molded body by decorating the outermost surface of a molded body with a decorative film has the advantage of offering greater freedom in design and superior productivity compared to methods of applying or printing on the surface using paint, etc. In addition, decoration methods using decorative films are used for various purposes because they can decorate molded body surfaces that have three-dimensional unevenness.

For example, Patent Document 1 discloses a laminate for decorative molding having a base layer and an adhesive layer, the adhesive layer having a silicone-based adhesive layer and an acrylic-based adhesive layer. Patent Document 2 discloses a vacuum molding sheet having an adhesive layer on the underside of a surface film. Here, the adhesive layer is made of a thermoplastic saturated copolymer polyester resin mixed with 1.5 to 2.5 equivalents of polyisocyanate and cured.

JP 2017-154410 A JP 2010-120209 A

In decorative moldings, it is of course required that the adherend and the decorative film are sufficiently adhered to each other and do not easily peel off. However, when decorative molding is performed under vacuum heating conditions or reduced pressure heating conditions, and when a polypropylene resin material is used for the adherend, there is a problem that the adhesion of the decorative film to the adherend is not fully exhibited when a conventional adhesive sheet for decorative molding (decorative film) is used.

Therefore, in order to solve these problems of the conventional technology, the inventors have carried out research with the aim of providing a decorative film that exhibits excellent adhesion to adherends containing polypropylene resin when decorative molding is performed under vacuum heating conditions or reduced pressure heating conditions.

As a result of intensive research to solve the above problems, the inventors have found that in a decorative film having a decorative layer, an adhesive layer, and a release layer in this order, by blending a block copolymer containing a block composed of an isopentane-derived structure, a terpene resin, and a process oil in the adhesive layer, a decorative film that exhibits excellent adhesion to an adherend containing a polypropylene resin can be obtained when decorative molding is performed under vacuum heating conditions or reduced pressure heating conditions.
Specifically, the present invention has the following configuration.

[1] A decorative film having a decorative layer, an adhesive layer, and a release layer in this order,
The adhesive layer contains a block copolymer including a block composed of an isopentane-derived structure, a terpene resin, and a process oil,
A decorative film for decorative molding under vacuum heating conditions or reduced pressure heating conditions.
[2] The block copolymer is
The decorative film according to [1], which is a block copolymer including a block composed of an isopentane-derived structure and a block composed of a styrene-based polymer.
[3] The terpene resin is at least one selected from the group consisting of terpene resins, aromatic modified terpene resins, and terpene phenol resins;
The softening point of the terpene resin is 60 to 130°C.
The decorative film according to [1] or [2], wherein the number average molecular weight of the terpene resin is 300 to 1,500.
[4] The decorative film according to any one of [1] to [3], wherein the content of the terpene resin is 40 to 200 parts by mass per 100 parts by mass of the block copolymer.
[5] The decorative film according to any one of [1] to [4], wherein the process oil is paraffin-based oil.
[6] The decorative film according to any one of [1] to [5], wherein the content of the process oil is 1 to 50 parts by mass based on 100 parts by mass of the block copolymer.
[7] The decorative film according to any one of [1] to [6], wherein the adhesive layer has a thickness of 0.5 to 20 μm.
[8] A decorated molded article obtained by laminating the decorative film according to any one of [1] to [7] to an adherend containing a polypropylene resin.
[9] The decorative molding according to [8], which is for use as an automobile part, an electronic device, or a building material.

According to the present invention, when decorative molding is performed under vacuum heating conditions or reduced pressure heating conditions, a decorative film that exhibits excellent adhesion to an adherend containing polypropylene resin can be obtained.

FIG. 1 is a cross-sectional view showing an example of the configuration of a decorative film. FIG. 2 is a cross-sectional view showing an example of the configuration of the decorative molded body.

The present invention will be described in detail below. The following explanation of the constituent elements may be based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower and upper limits.

(Decorative film)
The present invention relates to a decorative film having a decorative layer, an adhesive layer, and a release layer in this order, which is for decorative molding under vacuum heating conditions or reduced pressure heating conditions. Here, the adhesive layer contains a block copolymer containing a block composed of an isopentane-derived structure, a terpene resin, and a process oil. Since the decorative film of the present invention has the above-mentioned configuration, when decorative molding is performed under vacuum heating conditions or reduced pressure heating conditions, it exhibits excellent adhesion to an adherend containing a polypropylene resin. Therefore, the decorative film of the present invention is preferably used for bonding to an adherend containing a polypropylene resin as a main component.

Conventionally, polycarbonate resins and ABS resins have been used as the adherends of decorative molded bodies. For this reason, the specific configuration of decorative films for decorating adherends containing polypropylene resin as the main component has not been fully studied. Therefore, the present inventors have conducted extensive research into decorative molding of adherends containing polypropylene resin as the main component under vacuum heating conditions or reduced pressure heating conditions. As a result, the present inventors have succeeded in obtaining a decorative film that exhibits excellent adhesion to adherends containing polypropylene resin as the main component by providing an adhesive layer in the decorative film that contains a block copolymer containing a block composed of an isopentane-derived structure, a terpene resin, and a process oil.

Figure 1 is a cross-sectional view illustrating an example of the configuration of the decorative film of the present invention. As shown in Figure 1, the decorative film 30 has a decorative layer 21, an adhesive layer 11, and a release layer 25. In the decorative film 30, other layers may be provided between the decorative layer 21 and the adhesive layer 11, but in this embodiment, it is preferable that the decorative layer 21 and the adhesive layer 11 are laminated so as to be in direct contact with each other. In the decorative film 30, other layers may be provided between the adhesive layer 11 and the release layer 25, but in this embodiment, it is preferable that the adhesive layer 11 and the release layer 25 are laminated so as to be in direct contact with each other.

The decorative layer 21 may be a single layer, or may be a colored film in which a pigment or dye is kneaded into the substrate. In FIG. 1, the decorative layer 21 is depicted as a single layer, but the decorative layer 21 may have a multi-layer structure including at least a substrate and a decorative layer. When the decorative layer 21 includes a substrate and a decorative layer, the decorative layer in the decorative layer 21 is preferably provided on the surface in contact with the adhesive layer 11. The decorative layer may also be provided on the outermost layer of the decorative film (the surface opposite to the surface in contact with the adhesive layer 11). In such a case, a functional layer such as a hard coat layer or an anti-reflection layer may be provided on the outermost surface side of the decorative layer in addition to the decorative layer.

The release layer 25 may be a layer made of a single layer of release film, but it may also be release paper with a release agent layer. That is, the release layer 25 may be release paper or release film.

The decorative film of the present invention is for decorative molding under vacuum heating conditions or reduced pressure heating conditions. In this specification, molding under vacuum heating conditions or reduced pressure heating conditions is so-called TOM molding. The TOM molding method includes a step of laminating the decorative film onto an adherend under vacuum heating conditions or reduced pressure heating conditions, and a step of pressing the decorative film onto the adherend by an air pressure difference.

(Adhesive Layer)
The decorative film has an adhesive layer. In the present invention, the adhesive layer may be provided on both sides of the decorative layer, but it is preferable that one adhesive layer is provided on either one side of the decorative layer.

In this embodiment, the adhesive layer includes a block copolymer, a terpene resin, and a process oil. Here, the block copolymer includes a block composed of an isopentane-derived structure. The content of the terpene resin is preferably 40 parts by mass or more, more preferably 45 parts by mass or more, even more preferably 50 parts by mass or more, and particularly preferably 55 parts by mass or more, relative to 100 parts by mass of the block copolymer. The content of the terpene resin is preferably 200 parts by mass or less, more preferably 180 parts by mass or less, even more preferably 160 parts by mass or less, and particularly preferably 140 parts by mass or less, relative to 100 parts by mass of the block copolymer. By setting the content of the terpene resin within the above range, the interlayer adhesion between the adhesive layer and the polypropylene layer can be improved, and further, the interlayer adhesion between the adhesive layer and the decorative layer can also be improved.

The total content of the block copolymer and the terpene resin is preferably 50% by mass or more, and more preferably 60% by mass or more, based on the total mass of the adhesive layer. By setting the total content of the block copolymer and the terpene resin within the above range, the decorative film can exhibit excellent adhesion to an adherend containing a polypropylene resin, and further, the interlayer adhesion between the adhesive layer and the decorative layer can be improved.

The block copolymer contained in the adhesive layer preferably contains a block composed of an isopentane-derived structure and a block composed of a styrene-based polymer. In this specification, the isopentane-derived structure is the following structure. The block composed of the isopentane-derived structure is a block formed by polymerization of the isopentane-derived structure of the above structure. The isopentane-derived structure is preferably a propylene-ethylene copolymer.

The block composed of a styrene-based polymer is preferably a block composed of a styrene polymer or an α-methylstyrene polymer.

The block copolymer contained in the adhesive layer may contain a block composed of other polymers in addition to a block composed of an isopentane-derived structure and a block composed of a styrene-based polymer. Examples of blocks composed of other polymers include a block composed of an ethylene-derived structure and a block composed of a (meth)acrylic acid ester-based polymer.

In the block copolymer contained in the adhesive layer, if the block composed of an isopentane-derived structure is designated as A and the block composed of a styrene-based polymer is designated as B, the block copolymer may be a diblock copolymer with an A-B structure, or a triblock copolymer with an A-B-A structure or a B-A-B structure. It may also be a block copolymer having a repeating structure of each block, such as an -A-B-A-B- structure. Furthermore, as described above, it may be a block copolymer further containing a block composed of another polymer.

The block copolymer contained in the adhesive layer may further have a substituent in its polymer chain. For example, a block copolymer having a substituent with an unsaturated bond as a substituent may be used.

The block copolymers described above may be prepared by polymerization using known methods, but commercially available products may also be used. Examples of commercially available products that can be used include Septon 1020, Septon 2002, Septon 4033, and Septon HG252 manufactured by Kuraray Co., Ltd.

The terpene resin contained in the adhesive layer is preferably at least one selected from the group consisting of terpene resins, aromatic modified terpene resins, and terpene phenol resins. More specifically, examples of the terpene resins include α-pinene polymers, β-pinene polymers, dipentene polymers, and phenol-modified, aromatic modified, hydrogenated, and hydrocarbon modified terpene resins.

The softening point of the terpene resin is preferably 60°C or higher, more preferably 65°C or higher, even more preferably 70°C or higher, and particularly preferably 75°C or higher. The softening point of the terpene resin may be 100°C or higher. The softening point of the terpene resin is preferably 130°C or lower, and more preferably 125°C or lower. The softening point of the terpene resin is a value measured using an automatic softening point measuring device (FLEX SCIENTIFIC, EX-719PD4) in accordance with the method described in JIS K2207.

The number average molecular weight of the terpene resin is preferably 300 or more, more preferably 350 or more, and even more preferably 400 or more. The number average molecular weight of the terpene resin is preferably 1500 or less, more preferably 1400 or less, and even more preferably 1300 or less. The number average molecular weight of the terpene resin is measured by gel permeation chromatography (GPC) and calculated using a calibration curve prepared using standard polystyrene with a known molecular weight.

As the terpene resin, commercially available products may be used. Examples of commercially available products that can be used include YS Resin PX 1150, YS Resin PX 1250, YS Resin TO 125, YS Resin TO 105, YS Polystar T 125, YS Polystar T 80, and YS Polystar G 125, all manufactured by Yasuhara Chemical Co., Ltd.

The process oil contained in the adhesive layer may be one that is used as a plasticizer for rubber, thermoplastic elastomers, etc. Examples of the process oil include aromatic oils, naphthenic oils, and paraffinic oils. Among them, in this embodiment, it is preferable to use paraffinic oil as the process oil. By using paraffinic oil as the process oil, the adhesive layer is plasticized and the adhesion to the adherend can be improved.

The content of the process oil is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, per 100 parts by mass of the block copolymer. The content of the process oil is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less, per 100 parts by mass of the block copolymer. By setting the content of the process oil within the above range, the interlayer adhesion between the adhesive layer and the polypropylene layer can be improved, and further, the interlayer adhesion between the adhesive layer and the decorative layer can also be improved.

Commercially available process oils may be used. Examples of commercially available process oils that can be used include naphthenic process oils such as the Diana Process Oil NS series manufactured by Idemitsu Kosan Co., Ltd. and the SUNTHENE series manufactured by Nippon Sun Oil Co., Ltd., and paraffinic process oils such as the Diana Process Oil PW series manufactured by Idemitsu Kosan Co., Ltd. and the SUNPAR series manufactured by Nippon Sun Oil Co., Ltd.

The adhesive layer may contain additives in addition to the block copolymers and resins described above. Examples of additives include antioxidants (or antiaging agents), silane coupling agents, tackifiers other than terpene resins, softeners, crosslinking agents, pigments, and hydrogen abstraction initiators.

Examples of antioxidants include phenol-based antioxidants, amine-based antioxidants, lactone-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. These antioxidants may be used alone or in combination of two or more types.

Examples of silane coupling agents include mercapto-based silane coupling agents containing a mercapto group, epoxy-based silane coupling agents having an epoxy group, and vinyl-based silane coupling agents having a vinyl group. Of these, it is preferable to use a mercapto-based silane coupling agent for the application of the present invention. Examples of mercapto-based silane coupling agents include mercaptotrimethoxysilane, mercaptomethyltrimethoxysilane, mercaptomethyltriethoxysilane, triethoxy(2-mercaptoethyl)silane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 4-mercaptobutyltrimethoxysilane, 10-mercaptodecyltriethoxysilane, 11-mercaptoundecyltrimethoxysilane, and 11-mercaptoundecyltriethoxysilane.

Examples of tackifiers other than terpene resins include petroleum resins such as styrene resins, rosin resins, C5 resins, C9 resins, and C5/C9 resins.

Hydrogen abstraction initiators include benzophenone compounds such as methyl benzoylformate and 4-methylbenzophenone.

The thickness of the adhesive layer is preferably 0.5 μm or more, and more preferably 1 μm or more. The thickness of the adhesive layer is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. In this embodiment, it is possible to reduce the thickness of the adhesive layer in this way.

(Decorative layer)
The decorative film has a decorative layer. Here, the decorative layer may be a single-layer colored film in which a pigment or a dye is kneaded into a substrate, or the decorative layer may be a multi-layer film including a substrate and a decorative layer.

When the decorative layer is a multilayer film including a substrate and a decorative layer, the decorative layer is preferably a layer provided on the surface of the decorative film that is in contact with the adhesive layer. The decorative layer may also be provided on the outermost layer of the decorative film (the surface opposite to the surface that is in contact with the adhesive layer), in which case a functional layer such as a hard coat layer or an anti-reflection layer may be provided on the outermost layer.

The decorative layer is preferably a printed layer. The printed layer is formed by printing one side of the film-like substrate using an ink mainly composed of, for example, a thermosetting resin or an ultraviolet-curing resin. For printing, known printing methods such as inkjet printing and screen printing can be used. Examples of the film-like substrate to be printed include ABS resin (a copolymer of acrylonitrile, butadiene, and styrene), AS resin (a copolymer of acrylonitrile and styrene), acrylic resin, polyethylene terephthalate, polybutylene terephthalate, nylon, polyacetal, polyphenylene oxide, phenolic resin, urea resin, melamine resin, liquid crystal polymer, polytetrafluoroethylene, polyvinylidene fluoride, polysulfone, polyethersulfone, polyacetal, polyetheretherketone, polyphenylene sulfide, polyetherimide, polyamideimide, polycarbonate, polyolefin resin (polyethylene, polypropylene, etc.), polystyrene, and urethane resin. It is preferable that these substrates are capable of stretching in a manner that conforms to the adherend during the molding process. In addition, a transparent film is usually used as the film-like substrate, but a coloring agent such as carbon (graphite) may be blended to impart design features, or a colored layer may be used.

The decorative layer may further have a surface protective layer or a print protective layer to protect the printed layer. The surface protective layer is preferably a layer disposed on the most exposed surface side of the decorative layer and serves to enhance scratch resistance and weather resistance. For this reason, the surface protective layer is preferably a layer containing a curable resin layer, and more preferably a hard coat layer. Among them, the curable resin is preferably a photocurable resin, and more preferably an ultraviolet curable resin. In this case, the resin composition for forming the surface protective layer preferably contains, for example, a photopolymerization initiator in addition to the ultraviolet curable resin. In addition, when the decorative layer is formed by printing, depending on the ink used, it is easy to be scratched, so a print protective layer such as a hard coat layer may be provided on the ink layer to prevent scratches.

The surface protective layer may further contain fine particles. Examples of fine particles include inorganic fine particles, and metal oxides are preferred. In addition, if necessary, a pigment or a dye may be contained. In addition, if necessary, the surface protective layer may contain additives such as a pigment dispersant, a defoamer, an ultraviolet absorber, HAL, an antioxidant, an antistatic agent, an anti-abrasion agent, and an anti-blocking agent.

The decorative layer may further include a separator layer if there is a protective film or an adhesive layer on the outermost layer. The protective film or separator layer is provided to temporarily protect the surface protective layer. For example, it is provided to prevent the surface protective layer or the printed layer from being scratched before use. The protective film is preferably a self-adhesive film made of ethylene-vinyl acetate copolymer, or a slightly adhesive film in which a urethane-based and/or acrylic-based adhesive layer having removability is laminated on a PET film. The separator layer is preferably configured, for example, by providing a release layer such as silicone on the surface of the base layer as described above. Such a separator layer is peeled off during the manufacturing process or use, and removed from the decorative film or decorated molded body.

Examples of the configuration of the surface side layer include the following layer configurations: Note that, in order to bond each layer, an adhesive layer may be provided between each layer, if necessary.
(1) A configuration consisting of only a base layer. (2) A configuration in which a decorative layer and a surface protective layer are provided in this order. (3) A configuration in which a decorative layer and a base layer are provided in this order. (4) A configuration in which a base layer and a decorative layer are provided in this order. (5) A configuration in which a decorative layer, a base layer and a surface protective layer are provided in this order. (6) A configuration in which a protective film is further provided on the outermost surface of the above-mentioned configurations (1) to (5). (7) A configuration in which a pressure-sensitive adhesive layer and a separator layer are further provided on the outermost surface of the above-mentioned configurations (1) to (5).

When an adhesive layer is provided to bond each layer, a known adhesive can be used as the adhesive constituting the adhesive layer. Examples of adhesives include natural rubber adhesives, synthetic rubber adhesives, acrylic adhesives, urethane adhesives, and silicone adhesives. The adhesive may be solvent-based, solventless, emulsion-based, or water-based.

(Release Layer)
The decorative film has a release layer. The release layer may be a layer made of a single layer of release film, or may have a structure having a base material for the release layer and a release agent layer provided on one side of the base material for the release layer. Examples of the base material for the release layer include paper and polymeric films. Examples of the release agent constituting the release agent layer include addition type or condensation type silicone-based release agents and long-chain alkyl group-containing compounds. When the release layer is a layer made of a single layer of release film, it is preferable to use, for example, a Teflon film or a silicone film as the film.

(Method of manufacturing decorative film)
The method for producing a decorative film of the present invention includes a step of applying an adhesive composition onto a decorative layer, and drying or curing the composition to form an adhesive layer.

The adhesive composition can be applied by existing methods. When using an adhesive composition prepared by dissolving in a solvent, it can be applied using a knife coater or the like, and then the solvent can be dried in a drying oven to form a sheet. On the other hand, when using a pressure-sensitive adhesive prepared by a kneading method using heat, it can be formed into a sheet by using a hot melt coder, which can soften the adhesive composition by heating it in advance.

(Decorative Molded Body)
The present invention also relates to a decorated molded body obtained by bonding a decorative film to an adherend containing a polypropylene resin. In the decorated molded body, the adherend and at least the decorative film (or the decorative layer in the case of in-mold molding) are integrated with each other via an adhesive layer, and at least a part of the surface of the adherend is covered with the decorative film (or the decorative layer).

Figure 2 is a cross-sectional view illustrating an example of the configuration of a decorative molded body. As shown in Figure 2, the decorative molded body 100 has a configuration in which a decorative film 30 is laminated on an adherend 50. As shown in Figure 2, the decorative film 30 has a decorative layer 21 and an adhesive layer 11, and the adhesive layer 11 is directly attached to the adherend 50.

The adherend contains polypropylene resin. Here, the adherend contains polypropylene resin as a main component. Specifically, the content of polypropylene resin in the adherend is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. The content of polypropylene resin in the adherend may be 100% by mass, and the adherend may be made of polypropylene resin.

The shape of the adherend containing polypropylene resin is not particularly limited, and it may be a plate-like shape or may have a three-dimensional shape. In addition, the adherend may have an uneven structure on part of its surface.

The decorative molded body is preferably for use in automobile parts, electronic devices, or building materials. The present invention may relate to automobile parts, electronic devices, or building materials that include the above-mentioned decorative molded body. Examples of automobile parts include parts such as bodies, bumpers, spoilers, mirrors, wheels, emblems, and interior materials. Examples of electronic devices include electronic devices such as home appliances and liquid crystal display devices such as personal computers. Examples of building materials include furniture and building materials. Furthermore, the adherend may be road materials (e.g., traffic signs, soundproof walls, etc.), tunnel materials (e.g., side wall panels, etc.), musical instruments, containers, office supplies, sporting goods, toys, etc.

(Method for manufacturing decorated molded body)
The method for producing the decorative molded body preferably includes a step of bonding the decorative film to the adherend. The method for producing the decorative molded body preferably includes molding under vacuum heating conditions or reduced pressure heating conditions, and the above-mentioned decorative film is an adhesive sheet suitable for decorative molding under vacuum heating conditions or reduced pressure heating conditions.

The features of the present invention will be described in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below. In the following, Example 7 shall be read as Reference Example 7.

In this specification, molding under vacuum heating conditions or reduced pressure heating conditions does not include a method of bonding a laminate and a molded body by using a molded body with vacuum holes. Specifically, molding under vacuum heating conditions or reduced pressure heating conditions can be carried out using the "vacuum molding device" described in Japanese Patent No. 3733564.

The features of the present invention are explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, processing contents, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below.

<Production of Adhesive Composition>
Adhesive composition (A-1)
An adhesive composition (A-1) was obtained by dissolving 100 parts by mass of a block copolymer (Septon 1020, manufactured by Kuraray Co., Ltd.) having a structure represented by the following structural formula, 60 parts by mass of a terpene resin (YS Resin PX 1150, manufactured by Yasuhara Chemical Co., Ltd., softening point 115°C, number average molecular weight 1000), 5 parts by mass of a paraffinic oil (Diana Process Oil PW-32, manufactured by Idemitsu Co., Ltd.), and 0.6 parts by mass of an antioxidant (IRGANOX 1010, manufactured by BASF Co., Ltd.) in toluene to a solids concentration of 30% by mass.

Adhesive composition (A-2)
An adhesive composition (A-2) having a solid content concentration of 30 mass % was obtained in the same manner as in the preparation of adhesive composition (A-1), except that a resin having a structure represented by the following structural formula (Septon 2002, manufactured by Kuraray Co., Ltd.) was used as the block copolymer.

Adhesive composition (A-3)
An adhesive composition (A-3) having a solid content concentration of 30 mass % was obtained in the same manner as in the preparation of adhesive composition (A-1), except that a resin having a structure represented by the following structural formula (Septon 4033, manufactured by Kuraray Co., Ltd.) was used as the block copolymer.

Adhesive composition (A-4)
An adhesive composition (A-4) having a solid content concentration of 30 mass% was obtained in the same manner as in the preparation of adhesive composition (A-3), except that the terpene resin (manufactured by Yasuhara Chemical Co., Ltd., YS Resin PX 1150, softening point 115°C, number average molecular weight 1000) was changed to a terpene resin (manufactured by Yasuhara Chemical Co., Ltd., YS Resin PX 800, softening point 80°C, number average molecular weight 700) and the amount added was changed to 100 parts by mass.

Adhesive composition (A-5)
An adhesive composition (A-5) having a solid content concentration of 30 mass% was obtained in the same manner as in the preparation of adhesive composition (A-3), except that the terpene resin (Yasuhara Chemical Co., Ltd., YS Resin PX 1150, softening point 115°C, number average molecular weight 1000) was changed to an aromatic modified terpene resin (Yasuhara Chemical Co., Ltd., YS Resin TO 125, softening point 125°C, number average molecular weight 800).

Adhesive composition (A-6)
An adhesive composition (A-6) having a solid content concentration of 30 mass% was obtained in the same manner as in the preparation of adhesive composition (A-3), except that the terpene resin (manufactured by Yasuhara Chemical Co., Ltd., YS Resin PX 1150, softening point 115°C, number average molecular weight 1000) was changed to a terpene phenol resin (manufactured by Yasuhara Chemical Co., Ltd., YS Polystar T 80, softening point 80°C, number average molecular weight 500).

Adhesive composition (A-7)
A pressure-sensitive adhesive composition (A-7) having a solid content concentration of 30 mass% was obtained in the same manner as in the preparation of pressure-sensitive adhesive composition (A-3), except that the amount of paraffinic oil (Diana Process Oil PW-32, manufactured by Idemitsu Co., Ltd.) added was changed to 40 parts by mass.

Adhesive composition (B-1)
An adhesive composition (B-1) having a solids concentration of 30 mass % was obtained in the same manner as in the preparation of adhesive composition (A-1), except that a hydrogenated polybutadiene-based resin represented by the following structural formula (Septon 8004, manufactured by Kuraray Co., Ltd.) not having an isopentane-derived structure was used instead of the block copolymer having an isopentane-derived structure.

Adhesive composition (B-2)
An adhesive composition (B-2) having a solid content concentration of 30 mass% was obtained in the same manner as in the preparation of adhesive composition (A-3), except that a styrene-based resin (manufactured by Mitsui Chemicals, Inc., FTR8100, number average molecular weight 800) was used instead of the terpene resin.

Adhesive composition (C-1)
In a reaction vessel equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, n-butyl acrylate (BA) and 2-hydroxyethyl acrylate (2HEA) were mixed in a mass ratio of 80:20, and 2,2'-azobis(2,4-dimethylvaleronitrile) was dissolved in the solution as a radical polymerization initiator. The solution was heated to 60°C to randomly copolymerize the monomer components to obtain a copolymer solution. 0.11 parts by mass of a xylylene diisocyanate compound (Takenate D-110N, manufactured by Mitsui Chemicals, Inc.) was added as a crosslinking agent to 100 parts by mass of the solid content of the copolymer obtained above, and ethyl acetate was added so that the solid content concentration was 30% by mass to obtain an adhesive composition (C-1).

Adhesive composition (C-2)
Terephthalic acid: isophthalic acid: adipic acid were mixed as the acid component in a mass ratio of 30:30:40, and 1,4-butanediol and 1,6-hexanediol were mixed as the glycol component in a mass ratio of 25:75, and heated in the presence of a catalyst (tetrabutyl titanate) to obtain a thermoplastic saturated copolymerized polyester resin. The thermoplastic saturated copolymerized polyester resin obtained above was dissolved in a solvent (methyl ethyl ketone) and diluted and stirred to obtain a solution with a solid content concentration of 30% by mass. Next, 2 parts by mass of polyisocyanate (manufactured by Nippon Polyurethane, "Coronate HX" (hexamethylene diisocyanate), solid content concentration 100% by mass) was added to the solution to obtain an adhesive composition (C-2) with respect to 100 parts by mass of the thermoplastic saturated copolymerized polyester resin.

<Preparation of decorative film>
Example 1
The adhesive composition (A-1) prepared above was applied to an acrylic film (Kuraray Co., Ltd., Parapure HI grade, 75 μm) using a knife coater so that the adhesive layer after drying would be 5 μm thick, and then dried at 100° C. for 3 minutes to volatilize and dry the toluene solvent. Next, a glassine release paper (Oji Tack Co., Ltd., G6W 60 g/m ² ) was attached to the adhesive layer side using a hand roller to obtain a decorative film equipped with a release layer (release paper).

Example 2
A decorative film was obtained in the same manner as in Example 1, except that the adhesive composition (A-1) was changed to the adhesive composition (A-2).

Example 3
A decorative film was obtained in the same manner as in Example 1, except that the adhesive composition (A-1) was changed to the adhesive composition (A-3).

Example 4
A decorative film was obtained in the same manner as in Example 1, except that the adhesive composition (A-1) was changed to the adhesive composition (A-4).

Example 5
A decorative film was obtained in the same manner as in Example 1, except that the adhesive composition (A-1) was changed to the adhesive composition (A-5).

Example 6
A decorative film was obtained in the same manner as in Example 1, except that the adhesive composition (A-1) was changed to the adhesive composition (A-6).

(Example 7)
A decorative film was obtained in the same manner as in Example 1, except that the adhesive composition (A-1) was changed to the adhesive composition (A-7).

(Example 8)
A decorative film was obtained in the same manner as in Example 3, except that the thickness of the adhesive layer after drying was changed to 1 μm.

Example 9
A decorative film was obtained in the same manner as in Example 3, except that the thickness of the adhesive layer after drying was changed to 20 μm.

(Comparative Example 1)
A decorative film was obtained in the same manner as in Example 1, except that the adhesive composition (A-1) was changed to the adhesive composition (B-1).

(Comparative Example 2)
A decorative film was obtained in the same manner as in Example 1, except that the adhesive composition (A-1) was changed to the adhesive composition (B-2).

(Comparative Example 3)
A decorative film was obtained in the same manner as in Example 1, except that the adhesive composition (A-1) was changed to the adhesive composition (C-1).

(Comparative Example 4)
A decorative film was obtained in the same manner as in Comparative Example 1, except that the adhesive composition (A-1) was changed to the adhesive composition (C-2).

(Adhesion Evaluation)
<Preparation of Decorative Molded Body>
A decorated molded body was produced by the TOM method using the decorative film obtained in each Example and Comparative Example. First, a plate-shaped molded body made of a decorative film with the release layer (release paper) peeled off and a 100 mm x 100 mm x 2.0 mm thick polypropylene resin (Sumitomo Chemical Co., Ltd., Sumikasen (registered trademark)-L GA401) was set in a TOM molding machine (Fuse Vacuum Co., Ltd., NGF molding machine) so that the molded body and the adhesive layer of the decorative film faced each other. A decorated molded body was obtained by laminating the decorative film to the molded body at 120 ° C. using the TOM molding machine.
<Evaluation>
The decorative molded article prepared above was aged for 24 hours in an environment of 23°C and 50% relative humidity, and then the adhesion between the decorative film and the polypropylene resin adherend was evaluated in accordance with JIS K 5600-5-6. Specifically, an adhesion test was performed by the cross-cut method as follows.
First, a razor was used to make cuts on the decorative film side to create 100 1 mm x 1 mm grids, and then cellophane tape (CT28, manufactured by Nichiban Co., Ltd.) was pressed from above with a finger to adhere to the decorative film and then peeled off. If the decorative film was not peeled off in all of the 100 squares, it was scored as 100/100, and if the decorative film was peeled off in all of the squares, it was scored as 0/100. The number of squares where the decorative film was not peeled off was counted, and the adhesion of the decorative film was evaluated according to the following evaluation criteria.
A:80/100~100/100
B:50/100~79/100
C: 0/100~49/100

The decorative film obtained in the examples showed good adhesion to polypropylene resin substrates. On the other hand, the decorative film obtained in the comparative examples showed poor adhesion to polypropylene resin substrates. The decorative film obtained in the examples also showed good adhesion even when the heating temperature during decorative molding was relatively low (120°C).

REFERENCE SIGNS LIST 11 adhesive layer 21 decorative layer 25 release layer 30 decorative film 50 adherend 100 decorated molded body

Claims (6)

A decorative film having a decorative layer, an adhesive layer, and a release layer in this order,
The adhesive layer contains a block copolymer including a block composed of an isopentane-derived structure, a terpene resin, and a process oil,
The content of the process oil is 1 to 5 parts by mass based on 100 parts by mass of the block copolymer,
A decorative film for decorative molding under vacuum heating conditions or reduced pressure heating conditions. The block copolymer is
The decorative film according to claim 1 , which is a block copolymer comprising a block composed of an isopentane-derived structure and a block composed of a styrene-based polymer. The terpene resin is at least one selected from the group consisting of terpene resins, aromatic modified terpene resins, and terpene phenol resins;
The softening point of the terpene resin is 60 to 130° C.
The decorative film according to claim 1 or 2, wherein the terpene resin has a number average molecular weight of 300 to 1,500. The decorative film according to any one of claims 1 to 3, wherein the content of the terpene resin is 40 to 200 parts by mass per 100 parts by mass of the block copolymer. The decorative film according to any one of claims 1 to 4, wherein the process oil is paraffin-based oil. The decorative film according to any one of claims 1 to 5 , wherein the adhesive layer has a thickness of 0.5 to 20 µm.