JP7505539B2 - Resin composition for decorative film and decorative film using same - Google Patents

Description

The present invention relates to a decorative film for application to a resin molded body by thermoforming, and a method for manufacturing a decorative molded body using the decorative film. More specifically, the present invention relates to a decorative film for application to a resin molded body by thermoforming, which has excellent weather resistance before and after decorative molding, and a method for manufacturing a decorative molded body using the decorative film.

In recent years, there has been an increasing demand for decorative techniques to replace painting due to demands for reducing VOCs (volatile organic compounds), and various decorative techniques have been proposed.

In particular, a technology has been proposed in which a decorative film, which replaces a coating film, is applied to a molded body by vacuum-compressed air forming or vacuum forming to form a decorative molded product in which the decorative film and the molded body are integrated (see, for example, Patent Document 1), and this technology has been attracting particular attention in recent years.

Compared to other decorative molding methods such as insert molding, decorative molding using vacuum and compressed air molding offers greater freedom in shape, and the edge of the decorative film is wrapped around the back of the object to be decorated, resulting in no seams and an excellent appearance. Furthermore, because thermoforming can be performed at relatively low temperatures and pressures, it has the advantage of being excellent in reproducing textures such as grain applied to the surface of the decorative film.

JP 2002-67137 A

To impart weather resistance to decorative films, hindered amine light stabilizers and UV absorbers are sometimes added. However, decorative films containing such hindered amine light stabilizers and UV absorbers have the problem that their weather resistance is significantly impaired after decorative molding.

Conventional technology has not yet achieved a decorative film that suppresses the deterioration of weather resistance even after decorative molding by vacuum pressure forming and vacuum forming. The object of the present invention is to provide a decorative film that can be used for three-dimensional decorative thermoforming and that suppresses the deterioration of weather resistance after decorative molding, and a method for manufacturing a decorative molded body using the same.

The inventors conducted extensive research to solve the above problems and discovered that the hindered amine light stabilizer and/or ultraviolet absorber added to the resin to impart weather resistance volatilizes significantly during decorative molding, i.e., during the process of heating the decorative film under vacuum. On the other hand, they discovered that decorative films containing specific hindered amine light stabilizers and/or ultraviolet absorbers are less likely to volatilize the hindered amine light stabilizer and/or ultraviolet absorber even when heated under vacuum, and that deterioration in weather resistance can be suppressed even after decorative molding.

That is, the present invention encompasses the following:

(1) A decorative film containing a hindered amine-based light stabilizer and/or an ultraviolet absorber to be attached to a three-dimensional resin molded body by thermoforming, the hindered amine-based light stabilizer and/or ultraviolet absorber satisfying the following requirements:
Requirement: After carrying out the fogging test described below using a method in accordance with ISO 6452, the change in haze value of the glass plate measured using a method in accordance with JIS-K7136 is 40 or less.
<Fogging test> 1 g (±0.01 g) of a hindered amine light stabilizer or an ultraviolet absorber is placed in a glass sample bottle, the sample bottle is covered with a glass plate, and the glass plate is heated at 150° C. for 1 hour to generate fogging on the glass plate.

(2) The decorative film described in (1), in which the molecular weight of the hindered amine light stabilizer and/or UV absorber is 490 g/mol or more.

(3) The decorative film according to (1) or (2), which includes at least one layer containing the hindered amine-based light stabilizer and/or UV absorber, and the layer contains 50% by weight or more of a polyolefin-based resin.

(4) The decorative film according to (3), wherein the polyolefin resin is a polypropylene resin.

(5) A decorative film according to any one of (1) to (4), in which the outermost layer opposite the surface of the decorative film that is attached to the resin molded body contains the hindered amine-based light stabilizer and/or ultraviolet absorber.

(6) A method for manufacturing a decorative molded body, comprising the steps of preparing a decorative film according to any one of (1) to (5), preparing a resin molded body, setting the resin molded body and the decorative film in a chamber box capable of reducing the pressure, reducing the pressure inside the chamber box, heating and softening the decorative film, pressing the decorative film against the resin molded body, and restoring the pressure inside the reduced-pressure chamber box to atmospheric pressure or pressurizing it.

(7) The method for producing a decorative molded body described in (6), wherein the resin molded body is made of a polypropylene-based resin composition.

The decorative film of the present invention can provide a decorative film that can be used for three-dimensional decorative thermoforming and that suppresses deterioration in weather resistance after decorative molding, as well as a method for manufacturing a decorative molded body using the same.

1A to 1C are diagrams illustrating an example of a layer structure of a decorative film of the present invention. FIG. 2 is a schematic cross-sectional view illustrating an outline of an apparatus used in the method for producing a decorated molded body of the present invention. 3 is a schematic cross-sectional view illustrating a state in which a resin molded body and a decorative film are set in the device of FIG. 2. 3 is a schematic cross-sectional view illustrating a state in which the inside of the apparatus in FIG. 2 is heated and depressurized. FIG. 3 is a schematic cross-sectional view illustrating a state in which a decorative film is pressed against a resin molded body in the device of FIG. 2. 3 is a schematic cross-sectional view illustrating a state in which the inside of the device in FIG. 2 is returned to atmospheric pressure or pressurized. FIG. 4 is a schematic cross-sectional view illustrating a state in which unnecessary edges of a decorative film have been trimmed off in the obtained decorated molded body. FIG. 4A to 4C are diagrams showing examples of layer configurations of the obtained decorated molded body.

In this specification, decorative film refers to a film for decorating a molded body. Decorative molding refers to molding in which a decorative film is attached to a molded body. Three-dimensional decorative thermoforming refers to molding in which a decorative film is attached to a molded body, and includes a process in which the decorative film is thermoformed along the attachment surface of the molded body and is simultaneously attached, in which the thermoforming is performed under reduced pressure (vacuum) to prevent air from being trapped between the decorative film and the molded body, the heated decorative film is attached to the molded body, and the heated film is then tightly attached by releasing the pressure (pressurization). Below, the form for carrying out the present invention will be described in detail.

The decorative film of the present invention is a decorative film containing a hindered amine-based light stabilizer and/or an ultraviolet absorber for attachment to a three-dimensional resin molded body by thermoforming, and is characterized in that the hindered amine-based light stabilizer and/or ultraviolet absorber satisfy the following requirements:
Requirement: After carrying out the fogging test described below using a method conforming to ISO 6452, the change in haze value of the glass plate measured using a method conforming to JIS-K7136 is 40 or less. The change in haze value after the fogging test is calculated using the following formula.
Change in haze value after fogging test=Haze value of glass plate after fogging test−Haze value of glass plate before fogging test <Fogging test> 1 g (±0.01 g) of a hindered amine light stabilizer or UV absorber is placed in a glass sample bottle, the sample bottle is covered with a glass plate, and heated at 150° C. for 1 hour to generate fogging on the glass plate.

[Hindered amine light stabilizers and ultraviolet absorbers]
The hindered amine light stabilizer and/or ultraviolet absorber in the present invention is required to have a change in haze value of 40 or less, preferably 35 or less, more preferably 25 or less, and even more preferably 10 or less, when the change is measured by a method conforming to JIS-K7136 on a glass plate after the following fogging test is performed by a method conforming to ISO6452.
<Fogging test> 1 g (±0.01 g) of a hindered amine light stabilizer or an ultraviolet absorber is placed in a glass sample bottle, the sample bottle is covered with a glass plate, and the glass plate is heated at 150° C. for 1 hour to generate fogging on the glass plate.
In a typical fogging test, a resin composition sample containing the target additive is used, but in that case, it is not possible to grasp the volatility of the hindered amine light stabilizer and/or ultraviolet absorber in the decorative film of the present invention. In other words, this means that it is different from the bleeding phenomenon of a typical additive. By a fogging test in which the hindered amine light stabilizer or ultraviolet absorber is directly heated, it is possible to grasp the volatility of the hindered amine light stabilizer and/or ultraviolet absorber in the decorative film of the present invention.
When the haze value of the glass plate after the fogging test is within the above range, the hindered amine-based light stabilizer and/or ultraviolet absorber are unlikely to volatilize even during decorative molding, so that a decorated molded product with excellent weather resistance can be obtained. In addition, the hindered amine-based light stabilizer and/or ultraviolet absorber can be prevented from migrating to the surface (adhesive surface) of the decorative film, which can prevent the adhesive strength with the decorated product from decreasing. Furthermore, the inside of the chamber box of the thermoforming machine can be prevented from being soiled by the hindered amine-based light stabilizer and/or ultraviolet absorber.

The hindered amine light stabilizer or ultraviolet absorber (which is an additive, but in the following description, both may be referred to as "weathering agent" to distinguish them from other additives) in the present invention is not particularly limited as long as it satisfies the above conditions, but the molecular weight of the hindered amine light stabilizer or ultraviolet absorber is preferably 490 g/mol or more, more preferably 510 g/mol or more, and even more preferably 550 g/mol or more. By setting the molecular weight within the above range, the hindered amine light stabilizer and/or ultraviolet absorber is less likely to volatilize even under decorative molding conditions. There is no particular upper limit on the molecular weight, but it is practically preferable that it be 10,000 g/mol or less.

Specific examples of the hindered amine light stabilizer used in the present invention include, for example, poly{[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]}, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-butyl-2-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate, bis(2,2,6,6-tetramethyl-4-piperidyl)di(tridecyl) butane tetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) di(tridecyl)butane tetracarboxylate, 3,9-bis[1,1-dimethyl-2-{tris(2,2,6,6-tetramethyl-4-piperidyloxycarbonyloxy)butylcarbonyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, 3,9-bis[1,1-dimethyl-2-{tris(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyloxy)butylcarbonyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, 1,5,8,12-tetra 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol/dimethyl succinate condensate, 2-tert-octylamino-4,6-dichloro-s-triazine/N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine condensate, N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine/dibromoethane condensate, bis(2,2,6,6-tetramethyl-4-oxyl tetrakis(2,2,6,6-tetramethyl-4-oxylpiperidyl)butane-1,2,3,4-tetracarboxylate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)1,2,3,4-butane tetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)1,2,3,4-butane tetracarboxylate, 3,9-bis(1,1-dimethyl-2-(tris(2,2,6,6-tetramethyl-N-oxylpiperidyl-4-oxycarbonyl)butylcarbonyloxy)ethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, and the like. Among these, particularly preferred are poly{[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]}, 3,9-bis[1,1-dimethyl-2-{tris(2,2,6,6-tetramethyl-4-piperidyloxycarbonyloxy)butylcarbonyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, and tetrakis(2,2,6,6-tetramethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate.

Examples of commercially available products include LA-68 (registered trademark) and LA-57 (registered trademark) manufactured by ADEKA Corporation, and Chimassorb 944 (registered trademark) and Tinuvin 622 (registered trademark) manufactured by BASF Corporation.

Hindered amine light stabilizers can be used alone or in appropriate combination of two or more types.

The amount of the hindered amine light stabilizer added is preferably in the range of 0.001 to 1.00 parts by weight, and more preferably 0.005 to 0.50 parts by weight, per 100 parts by weight of the resin that constitutes the layer containing the light stabilizer. If the amount added is in the above range, a decorative film and a decorative molded article with good weather resistance can be obtained.

Specific examples of ultraviolet absorbents used in the present invention include 2,2'-methylenebis(4-t-octyl-6-benzotriazolyl)phenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol, and 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine.

Commercially available products include, for example, LA-31G (registered trademark), LA-46 (registered trademark), and LA-F70 (registered trademark) manufactured by ADEKA Corporation.

The ultraviolet absorbers can be used alone or in appropriate combination of two or more types.

The amount of UV absorber added is preferably in the range of 0.001 to 1.00 parts by weight, and more preferably 0.005 to 0.50 parts by weight, per 100 parts by weight of the resin that constitutes the layer containing the UV absorber. If the amount added is in the above range, a decorative film and a decorative molded article with good weather resistance can be obtained.

In addition, both a hindered amine light stabilizer and an ultraviolet absorber may be included. In that case, the total amount of both weathering agents is preferably in the range of 0.002 to 2.00 parts by weight, and more preferably 0.01 to 1.00 parts by weight, per 100 parts by weight of the resin that constitutes the layer containing the weathering agent.

By setting the content ratio of the hindered amine light stabilizer and the ultraviolet absorber within a specific range, a higher effect can be achieved. The blending ratio of the two weather resistance agents is preferably hindered amine light stabilizer/ultraviolet absorber = 1/5 to 5/1, and more preferably 1/4 to 4/1. By including both weather resistance agents, a synergistic effect between the weather resistance agents can be achieved, resulting in a decorative film and a decorative molded body with better weather resistance.

[Layer Containing Hindered Amine-Based Light Stabilizer and/or Ultraviolet Absorber]
The decorative film of the present invention includes at least one layer containing a hindered amine-based light stabilizer and/or an ultraviolet absorber. The decorative film may be composed of only a layer containing the hindered amine-based light stabilizer and/or an ultraviolet absorber, or may have a multilayer structure including other layers. By including a layer containing the weathering agent, a decorative film and a decorated molded body having good weather resistance can be obtained. In particular, since deterioration due to light progresses from the surface of the molded body, it is more preferable that the weathering agent is included in the outermost layer opposite the surface of the decorative film that is attached to the resin molded body.

[Polyolefin resin]
In the present invention, the layer containing the hindered amine-based light stabilizer and/or the ultraviolet absorber preferably contains 50% by weight or more of a polyolefin-based resin from the viewpoints of moldability, recyclability, solvent resistance, and the like. The layer more preferably contains 60% by weight or more of a polyolefin-based resin, and particularly preferably contains 70% by weight or more. In the present invention, the polyolefin-based resin refers to a resin containing 50 mol% or more of polymerized units derived from an olefin monomer. In the present invention, the modified polyolefin is a concept that includes polyolefin-based resins, and refers to a resin containing polymerized units derived from an olefin monomer and polymerized units derived from other monomers in any ratio. The polyolefin-based resin is preferably a homopolymer of an α-olefin such as ethylene, propylene, or butene, or a copolymer of ethylene, propylene, or the like with another α-olefin. Specifically, it is high-density polyethylene, low-density polyethylene, ethylene-α-olefin copolymer, propylene homopolymer (homopolypropylene), propylene-α-olefin copolymer (random polypropylene), propylene block copolymer (block polypropylene), and the like. Examples of monomer components other than the olefin monomer that constitute the polyolefin resin include aromatic monomers such as styrene; and polar group-containing monomers such as maleic anhydride and acrylic acid. However, it is preferable that the polyolefin resin does not contain polymerization units derived from the polar group-containing monomer.
Among these, polypropylene-based resins such as propylene homopolymer (homopolypropylene), propylene-α-olefin copolymer (random polypropylene), and propylene block copolymer (block polypropylene) are particularly preferred, and combinations of these can also be selected. The polypropylene-based resin preferably contains 50 mol % or more of polymerization units derived from propylene monomers. The polypropylene-based resin is preferably homopolypropylene from the viewpoints of oil resistance, solvent resistance, scratch resistance, heat resistance, and the like. Furthermore, from the viewpoints of gloss and transparency (color development), propylene-α-olefin copolymers are preferred.

The polypropylene resin in the present invention can be a resin polymerized by a Ziegler catalyst, a metallocene catalyst, or the like. That is, the polypropylene resin can be a Ziegler catalyst-based propylene polymer or a metallocene catalyst-based propylene polymer.

The resin constituting the layer containing the hindered amine light stabilizer and/or UV absorber may contain additives other than the weathering agent, fillers, other resin components, etc., as long as the effects of the present invention are not impaired. However, the total amount of other additives, fillers, other resin components, etc. is preferably 50% by weight or less based on the resin composition.

Other additives that can be blended include various known additives such as antioxidants, neutralizing agents, antiblocking agents, lubricants, antistatic agents, metal deactivators, and nucleating agents.

Examples of antioxidants include phenol-based antioxidants, phosphite-based antioxidants, and thio-based antioxidants. Examples of neutralizing agents include higher fatty acid salts such as calcium stearate and zinc stearate.

Examples of lubricants include higher fatty acid amides such as stearic acid amide. Examples of antistatic agents include fatty acid partial esters such as glycerin fatty acid monoester. Examples of metal deactivators include triazines, phosphons, epoxies, triazoles, hydrazides, oxamides, etc.

Nucleating agents are components added to decorative films to impart transparency, surface gloss, etc. Examples of nucleating agents include metal salts of aromatic carboxylates, metal salts of aromatic phosphates, sorbitol derivatives, nonitol derivatives, amide compounds, and metal salts of rosin. Among these nucleating agents, examples include aluminum p-t-butylbenzoate, sodium 2,2'-methylenebis(4,6-di-t-butylphenyl)phosphate, 2,2'-methylenebis(4,6-di-t-butylphenyl)aluminum phosphate, complexes of bis(2,4,8,10-tetra-tert-butyl-6-hydroxy-12H-dibenzo[d,g][1,2,3]dioxaphosphocin-6-oxide) hydroxide aluminum salt and organic compounds, p-methyl-benzylidene sorbitol, p-ethyl-benzylidene sorbitol, 1,2,3-trideoxy-4,6:5,7-bis-[(4-propylphenyl)methylene]-nonitol, and sodium salt of rosin.

As the filler, various fillers such as inorganic fillers and organic fillers can be blended. Examples of inorganic fillers include calcium carbonate, silica, hydrotalcite, zeolite, aluminum silicate, magnesium silicate, glass fiber, carbon fiber, etc. Examples of organic fillers include crosslinked rubber fine particles, thermosetting resin fine particles, hollow thermosetting resin fine particles, etc.

Other resin components include styrene-based elastomers, modified polyolefin resins containing less than 50 mol% of polymerization units derived from olefin monomers, petroleum resins, and other thermoplastic resins.

It is also possible to color it to add design features, and various colorants such as inorganic pigments, organic pigments, and dyes can be used for coloring. Luster materials such as aluminum flakes, titanium oxide flakes, and (synthetic) mica can also be used.

When the decorative molded body according to the present invention is molded as a colored molded body, it is only necessary to use a colorant in the decorative film, so it is possible to reduce the use of expensive colorants compared to when the entire resin molded body is colored. In addition, it is possible to suppress changes in physical properties that accompany the blending of a colorant.

In the present invention, the resin composition containing a hindered amine-based light stabilizer and/or an ultraviolet absorber can be produced by a method of melt-kneading a resin with a hindered amine-based light stabilizer and/or an ultraviolet absorber, other additives, fillers, other resin components, etc., a method of dry-blending a hindered amine-based light stabilizer and/or an ultraviolet absorber with a melt-kneaded mixture of a resin with other additives, fillers, other resin components, etc., or a method of dry-blending a master batch in which a hindered amine-based light stabilizer and/or an ultraviolet absorber, other additives, fillers, other resin compositions, etc. are dispersed in a carrier resin at a high concentration with a resin.

[Decorative film]
The decorative film of the present invention includes at least one layer containing a hindered amine-based light stabilizer and/or an ultraviolet absorber. That is, the decorative film may be a single-layer film consisting of only a layer containing the hindered amine-based light stabilizer and/or an ultraviolet absorber, or a multilayer film consisting of a layer containing the hindered amine-based light stabilizer and/or an ultraviolet absorber and other layers. The decorative film of the present invention may also have a surface that is textured, embossed, printed, sandblasted, scratched, etc.

Three-dimensional decorative thermoforming allows for a high degree of freedom in the shape of the object to be decorated, and because the end faces of the decorative film are wrapped around the back side of the object to be decorated, there are no seams, resulting in an excellent appearance. Furthermore, by imparting a texture such as embossing to the surface of the decorative film, various textures can be expressed. For example, when imparting a texture such as embossing to a resin molded body, three-dimensional decorative thermoforming can be performed using an embossed decorative film. This solves the problems associated with molding using a mold that imparts embossing, namely, that a mold for the mold is required for each embossing pattern, and that it is extremely difficult and expensive to apply complex embossing to a mold with a curved surface, and makes it possible to easily obtain a decorated molded body that has been embossed in a variety of patterns.

In a preferred embodiment of the decorative film, when it is a monolayer film, it is preferable that it contains a resin with excellent thermoformability. For example, when the resin constituting the film is a polypropylene-based resin, it is preferable that (i) the resin composition (X) contains a polypropylene-based resin having a long-chain branched structure, and the resin composition (X) has a melt flow rate (MFR) (temperature 230°C, load 2.16 kg) of 0.1 to 40 g/10 min and a strain hardening degree λ of 1.1 or more, and/or (ii) the resin composition (Y) contains a linear polypropylene-based resin, and the MFR of the resin composition (Y) is 0.1 to 2.0 g/10 min. By using the resin composition (X) and/or (Y), a decorative molded product with good appearance can be obtained.

Resin composition (X) containing polypropylene resin having long chain branched structure
The resin composition (X) containing a polypropylene resin having a structure with long chain branches, which is preferred as a resin having excellent thermoformability, will be described below.

(X1) Melt flow rate (MFR(X))
If the viscosity of the resin composition (X) is too low, sufficient molding stability cannot be obtained. Therefore, the resin composition (X) must have a certain viscosity. In the present invention, the MFR (230° C., 2.16 kg load) is specified as an index of this viscosity.

In this specification, the MFR (230°C, 2.16 kg load) of resin composition (X) is referred to as MFR(X). MFR(X) preferably satisfies the following requirement (x1), more preferably satisfies requirement (x1'), and even more preferably satisfies requirement (x1"). By setting the MFR(X) of resin composition (X) to the following value or less, a decorated molded article with good appearance can be obtained.
(x1) MFR(X) is 40 g/10 min or less.
(x1') MFR(X) is 20 g/10 min or less.
(x1″) MFR(X) is 12 g/10 min or less.

There is no particular restriction on the lower limit of MFR(X) of resin composition (X), but it is preferably 0.1 g/10 min or more, more preferably 0.3 g/10 min or more. By making MFR(X) equal to or greater than the above value, the formability during production of the decorative film is improved, and the occurrence of poor appearance on the film surface, known as sharkskin or interface roughness, can be suppressed.

In the present invention, the MFR of the polypropylene resin and polypropylene resin composition is measured in accordance with ISO 1133:1997 Conditions M at 230°C and a load of 2.16 kg. The unit is g/10 min.

(X2) Strain hardening degree λ
The strain hardening degree λ of the resin composition (X) preferably satisfies the following requirement (x2), more preferably satisfies requirement (x2'), and even more preferably satisfies requirement (x2"). By setting the strain hardening degree λ of the resin composition (X) to a value within the following range, it is possible to obtain a decorated molded product that has good moldability during decorative thermoforming and excellent appearance.
(x2) The strain hardening degree λ is 1.1 or more.
(x2') The strain hardening degree λ is 1.8 or more.
(x2″) Strain hardening degree λ is 2.3 or more.

There is no particular upper limit for the strain hardening degree λ of the resin composition (X), but it is preferably 50 or less, and more preferably 20 or less. By setting the strain hardening degree λ to a value within the above range, the appearance of the decorative film can be improved.

The strain hardening degree λ of the polypropylene resin and the resin composition (X) is obtained based on the measurement of strain hardening in the extensional viscosity measurement. The strain hardening (nonlinearity) of the extensional viscosity is described in "Lecture on Rheology" edited by the Japan Society of Rheology, Polymer Publishing Society, 1992, pp. 221-222. In this specification, the strain hardening degree λ is calculated by a method based on the method shown in Figure 7-20 of the same book, and η ^* (0.01) is adopted as the value of the shear viscosity, and ηe (3.5) is adopted as the value of the extensional viscosity, and the strain hardening degree λ is defined by the following formula (b-1).
λ = ηe (3.5) / {3 × η ^* (0.01)} Formula (b-1)
In the above formula (b-1), η ^* (0.01) is the complex viscosity [unit: Pa·s] measured by a dynamic frequency sweep experiment at a measurement temperature of 180° C. and an angular frequency ω = 0.01 rad/s, and the complex viscosity η ^* is calculated from the complex elastic modulus G ^* [unit: Pa] and the angular frequency ω by η ^* = G ^* /ω. Also, ηe (3.5) is the extensional viscosity measured by extensional viscosity measurement at a measurement temperature of 180° C., a strain rate of 1.0 s ^-1 , and a strain of 3.5.

Usually, the data obtained by these viscoelasticity measurements are a collection of numerical values such as elastic modulus and viscosity at each discrete frequency or measurement time interval. Therefore, when measurements are performed using equipment or conditions different from those used in the present invention, data on the complex viscosity coefficient η ^* (0.01) at angular frequency ω = 0.01 rad/s or the extensional viscosity ηe (3.5) at strain amount 3.5 may not necessarily exist, but in that case, it is permissible to estimate the corresponding value by performing linear interpolation, spline interpolation, or other interpolation using data before and after the corresponding values. When performing the interpolation, it is common practice to use a logarithmic scale for the scale of stress or time.

In this case, if the sample does not have strain hardening (nonlinearity) in the extensional viscosity, the strain hardening degree λ will be approximately 1 (e.g., 0.9 or more and less than 1.1) or a smaller value, and the stronger the strain hardening (nonlinearity), the larger the value of the strain hardening degree λ.

Generally, crystalline polypropylene is a linear polymer and does not usually have strain hardening properties. In contrast, the polypropylene-based resin preferably used in the present invention is preferably a polypropylene-based resin (X-L) having a long-chain branched structure, which allows the resin composition (X) to exhibit good strain hardening properties.

The long-chain branch structure in this invention refers to a branch structure in which the carbon skeleton (main chain of the branch) constituting the branch has several tens or more carbon atoms, and the molecular weight is several hundred or more. This long-chain branch structure is to be distinguished from the short-chain branch structure formed by copolymerization with an α-olefin such as 1-butene.

Methods for introducing long chain branching structures into polypropylene-based resins include irradiating polypropylene that does not have long chain branching structures with high energy ionizing radiation (JP Patent Publication 62-121704), reacting polypropylene that does not have long chain branching structures with organic peroxides (JP Patent Publication 2001-524565), and producing a macromonomer with terminal unsaturated bonds and copolymerizing it with propylene (JP Patent Publication 2001-525460). Regardless of which method is used to produce the polypropylene-based resin, the strain hardening degree λ can be increased.

The polypropylene resin (X-L) having a long chain branching structure is not particularly limited as long as it has a long chain branching structure, but is preferably a polypropylene resin produced by a method other than the crosslinking method, and is preferably a polypropylene resin obtained by a method using a macromer copolymerization method in which a comb-shaped chain structure is formed during polymerization. Examples of such methods include those disclosed in JP-T-2001-525460, JP-A-10-338717, JP-T-2002-523575, JP-A-2009-57542, JP-A-5027353, and JP-A-10-338717. In particular, the macromer copolymerization method of JP-T-2009-57542 can obtain a long chain branching-containing polypropylene resin (X-L) without generating gel, and is suitable for the present invention.

The presence of long chain branching structure in polypropylene is defined by a method based on the rheological properties of the resin, a method of calculating the branching index g' using the relationship between molecular weight and viscosity, a method using ¹³ C-NMR, etc. In the present invention, the long chain branching structure is defined by the branching index g' and/or ¹³ C-NMR as shown below.

{Branching index g'}
The branching index g' is known as a direct index regarding the long chain branching structure. A detailed explanation is given in "Developments in Polymer Characterization-4" (J.V. Dawkins ed. Applied Science Publishers, 1983), and the branching index g' is defined as follows:
Branching index g' = [η]br/[η]lin
[η]br: intrinsic viscosity of polymer (br) having a structure of long chain branches [η]lin: intrinsic viscosity of a linear polymer having the same molecular weight as polymer (br) As is clear from the above definitions, when the branching index g' is a value smaller than 1, it is determined that a structure of long chain branches is present, and the more the structure of long chain branches increases, the smaller the value of the branching index g' becomes.

The branching index g' can be obtained as a function of the absolute molecular weight Mabs by using GPC equipped with a light scattering meter and a viscometer as detectors. The method for measuring the branching index g' in the present invention is described in detail in JP 2015-40213 A, but is as follows.
{Measuring method}
GPC: Alliance GPCV2000 (manufactured by Waters)
Detectors: listed in order of connection Multi-angle laser light scattering detector (MALLS): DAWN-E (manufactured by Wyatt Technology)
Differential refractometer (RI): GPC included Viscometer: GPC included Mobile phase solvent: 1,2,4-trichlorobenzene (Irganox 1076 added at a concentration of 0.5 mg/mL)
Mobile phase flow rate: 1 mL/min Column: Tosoh Corporation GMHHR-H(S) HT, two columns connected Sample injection temperature: 140°C
Column temperature: 140 ° C.
Detector temperature: all 140°C
Sample concentration: 1 mg/mL
Injection volume (sample loop volume): 0.2175 mL

{analysis method}
The absolute molecular weight (Mabs), the root mean square radius of gyration (Rg) obtained from a multi-angle laser light scattering detector (MALLS), and the intrinsic viscosity ([η]) obtained from a viscometer are calculated using ASTRA (version 4.73.04), a data processing software provided with the MALLS, with reference to the following literature:
References:
1. "Developments in Polymer Characterization-4" (J.V. Dawkins ed. Applied Science Publishers, 1983. Chapter 1.)
2. Polymer, 45, 6495-6505 (2004)
3. Macromolecules, 33, 2424-2436 (2000)
4. Macromolecules, 33, 6945-6952 (2000)

In the decorative film of the present invention, if the polypropylene resin or resin composition (X) having a long-chain branching structure contains gel, the appearance of the film deteriorates, so it is preferable to use a polypropylene resin or resin composition (X) that does not contain gel. In particular, as the polypropylene resin (X-L) having a long-chain branching structure described above, it is preferable to use a method in which a macromonomer having a terminal unsaturated bond is produced using a metallocene catalyst having a specific structure and the macromonomer is copolymerized with propylene to form a long-chain branching structure. In particular, it is preferable that the branching index g' at an absolute molecular weight Mabs of 1 million described below satisfies 0.3 or more and less than 1.0, more preferably 0.55 or more and 0.98 or less, even more preferably 0.75 or more and 0.96 or less, and most preferably 0.78 or more and 0.95 or less. In the present invention, "low gel content" means that the branching index g' of the polypropylene resin at an absolute molecular weight Mabs of 1 million is within the above range. When the branching index g' is within this range, highly cross-linked components are not formed, and no or very little gel is produced, so the appearance is not impaired, particularly when the layer containing the polypropylene resin (X-L) constitutes the surface of the product.

{ ^13C -NMR}
¹³ C-NMR can distinguish between short-chain branched structures and long-chain branched structures. A detailed explanation is given in Macromol. Chem. Phys. 2003, vol. 204, 1738, but the summary is as follows.

A polypropylene-based resin having a long chain branched structure has a specific branched structure as shown in the following structural formula (1): In structural formula (1), C _a , C _b and C _c represent methylene carbons adjacent to the branched carbons, C _br represents a methine carbon at the root of the branched chain, and P ¹ , P ² and P ³ represent a propylene-based polymer residue.

The propylene-based polymer residues P ¹ , P ² and P ³ may themselves contain a branching carbon (C _br ) other than the C _br depicted in the structural formula (1).

Such a branched structure is identified by ¹³ C-NMR analysis. The assignment of each peak can be determined by referring to the description in Macromolecules, Vol. 35, No. 10, 2002, pp. 3839-3842. That is, three methylene carbons (C _a , C _b and C _c ) are observed at 43.9-44.1 ppm, 44.5-44.7 ppm and 44.7-44.9 ppm, respectively, and a methine carbon (C _br ) is observed at 31.5-31.7 ppm. Hereinafter, the methine carbon observed at 31.5-31.7 ppm may be abbreviated as a branched methine carbon (C _br ).

The ¹³ C-NMR spectrum of a polypropylene resin having a long-chain branched structure is characterized in that the three methylene carbons adjacent to the branched methine carbon C _br are observed as three diastereotopic, unequal, separated carbons.

Such branched chains as assigned by ^13C -NMR indicate propylene polymer residues having 5 or more carbon atoms branched from the main chain of a polypropylene resin, and can be distinguished from branches having 4 or less carbon atoms by the difference in the peak positions of the branched carbons. Therefore, in the present invention, the presence or absence of a long chain branched structure can be determined by confirming the peak of this branched methine carbon.
The method for measuring ¹³ C-NMR in the present invention is as follows.

{ ^13C -NMR measurement method}
200 mg of the sample was dissolved in an NMR sample tube with an inner diameter of 10 mm together with 2.4 ml of o-dichlorobenzene/deuterated bromide benzene (C ₆ D ₅ Br)=4/1 (volume ratio) and hexamethyldisiloxane as a chemical shift standard substance, and ¹³ C-NMR measurement was performed.
¹³ C-NMR measurements were carried out using an AV400M NMR apparatus manufactured by Bruker Biospin Corp. equipped with a 10 mmφ cryoprobe.
The measurement was performed at a sample temperature of 120° C. using the proton complete decoupling method. Other conditions were as follows.
Pulse angle: 90°
Pulse interval: 4 seconds Number of accumulations: 20,000 The chemical shift was set with the peak of the methyl carbon of hexamethyldisiloxane set at 1.98 ppm, and the chemical shifts of peaks due to other carbons were set to this as the reference.
The peak near 44 ppm can be used to calculate the amount of long chain branching.

In the ^13C -NMR spectrum of the polypropylene resin (XL) having a long chain branch structure, the amount of long chain branches quantified from a peak near 44 ppm is preferably 0.01/1000 total propylene or more, more preferably 0.03/1000 total propylene or more, and even more preferably 0.05/1000 total propylene or more. If this value is too large, it may cause defects in appearance such as gels and fish eyes, so the amount is preferably 1.00/1000 total propylene or less, more preferably 0.50/1000 total propylene or less, and even more preferably 0.30/1000 total propylene or less.

The polypropylene resin (X-L) having such a long chain branching structure may be contained in the resin composition (X) in an amount sufficient to impart strain hardening properties. The polypropylene resin (X-L) having a long chain branching structure is contained in an amount of preferably 1 to 100% by weight, more preferably 5% by weight or more, per 100% by weight of the resin composition (X).

The polypropylene-based resin (X-L) having a long chain branching structure in the present invention can be selected from various types of propylene-based polymers such as propylene homopolymer (homopolypropylene), propylene-α-olefin copolymer (random polypropylene), propylene block copolymer (block polypropylene), or combinations thereof. The polypropylene-based resin preferably contains 50 mol % or more of polymerization units derived from propylene monomers.

Resin composition (Y) containing linear polypropylene resin
The resin composition (Y) containing a linear polypropylene resin, which is preferred as a resin having excellent thermoformability, will be described.

Resin composition (Y) containing a linear polypropylene resin suitable for the present invention preferably has an MFR (230°C, 2.16 kg load) of 2.0 g/10 min or less, more preferably 1.5 g/10 min or less, and even more preferably 1.0 g/10 min or less. By setting the MFR of resin composition (Y) to the above value or less, a decorated molded product with good appearance can be obtained.

There is no particular restriction on the lower limit of the MFR of the resin composition (Y), but it is preferably 0.1 g/10 min or more, and more preferably 0.3 g/10 min or more. By making the MFR equal to or greater than the above value, the moldability during production of the decorative film is improved, and the occurrence of poor appearance on the film surface, known as sharkskin or interface roughness, can be suppressed.

As another preferred embodiment of the decorative film, when it is a multilayer film, it may include a surface layer, a surface decorative layer, a printing layer, a light-shielding layer, a colored layer, a base layer, a sealing layer, a barrier layer, and a tie layer layer that may be provided between these layers. The layer containing the hindered amine-based light stabilizer and/or the ultraviolet absorber of the present invention may be any layer constituting the multilayer film. In addition, multiple layers may contain the weathering agent, or all layers may contain the weathering agent. In particular, since deterioration due to light progresses from the surface of the molded body, it is more preferable that the weathering agent is contained in the outermost layer opposite the surface of the decorative film that is attached to the resin molded body.

In the multilayer film, the layers other than the layer containing the hindered amine-based light stabilizer and/or UV absorber are preferably layers made of a thermoplastic resin, more preferably layers made of a polypropylene-based resin. In the case of a polypropylene-based resin, various types of propylene-based polymers such as propylene homopolymer (homopolypropylene), propylene-α-olefin copolymer (random polypropylene), propylene block copolymer (block polypropylene), or combinations thereof can be selected. Each layer is preferably a layer that does not contain a thermosetting resin. By using a thermoplastic resin, recyclability is improved. Furthermore, by using a polypropylene-based resin, the layer structure can be prevented from becoming complicated, and co-extrusion properties and recyclability are further improved.

For example, when the decorative film is a multilayer film with a two-layer structure, it can be made up of two layers: a surface layer that becomes the surface of the decorative molded body and a base layer that is attached to the molded body, or a base layer that becomes the surface of the decorative molded body and a seal layer that is attached to the molded body. Furthermore, when the decorative film is a multilayer film with a three-layer structure, it can be made up of three layers: a surface layer that becomes the surface of the decorative molded body, a seal layer that is attached to the molded body, and a base layer that is interposed between the surface layer and the seal layer. It may also be a multilayer film with a more complex layer structure, and at least one layer that constitutes the multilayer film contains a hindered amine-based light stabilizer and/or an ultraviolet absorber.

It is preferable that the outermost layer of the decorative film, which is opposite to the surface to be attached to the resin molded body, contains a hindered amine-based light stabilizer and/or an ultraviolet absorber. For example, when the decorative film is composed of two layers, a surface layer and a base layer, it is preferable that the surface layer contains a hindered amine-based light stabilizer and/or an ultraviolet absorber. When the decorative film is composed of two layers, a base layer and a seal layer, it is preferable that the base layer contains a hindered amine-based light stabilizer and/or an ultraviolet absorber. When the decorative film is composed of three layers, a surface layer, a base layer and a seal layer, it is preferable that the surface layer contains a hindered amine-based light stabilizer and/or an ultraviolet absorber.

[Base layer]
In the present invention, the base layer refers to the layer with the largest thickness in the decorative film. When the decorative film is a monolayer film, the layer is the base layer. When the resin constituting the base layer of the decorative film of the present invention is a polypropylene-based resin, it is preferable that the base layer contains the resin composition (X) and/or (Y) as in the case of the monolayer film. This improves the thermoformability, and a decorative molded product with good appearance can be obtained.

[Surface layer and surface decorative layer]
In the present invention, the surface layer and the surface decoration layer refer to a layer other than the base layer that constitutes the outermost layer opposite to the surface to be attached to the resin molded body. The surface layer and the surface decoration layer may be provided directly on the base layer, or may be provided after one or more other layers are interposed on the base layer. Here, the surface decoration layer refers to a surface layer to which a nucleating agent, a colorant, etc. are added in order to improve the transparency, surface gloss, design, etc. of the decorative film.
When the resin constituting the surface layer or surface decorative layer of the decorative film of the present invention is a polypropylene-based resin, the MFR (230 ° C., 2.16 kg load) is preferably more than 2.0 g / 10 minutes, more preferably 5.0 g / 10 minutes or more, and even more preferably 9.0 g / 10 minutes or more. By setting the MFR of the polypropylene-based resin within the above value range, the surface smoothness and gloss of the decorative film can be improved, and the effect of improving the grain transferability can be obtained, and a decorative molded body having a good appearance can be obtained with respect to the required surface shape of the molded body (gloss, non-gloss, grain, etc.). In addition, the transferability of the surface during the production and thermoforming of the decorative film is improved, and if a mirror roll is used during thermoforming, a decorative film with a higher gloss can be obtained. There is no particular limit to the upper limit of the MFR, but it is preferably 100 g / 10 minutes or less, more preferably 50 g / 10 minutes or less. By setting the MFR within the above value range, good oil resistance, solvent resistance, scratch resistance, etc. can be exhibited.

[Sealing layer]
In the present invention, the seal layer refers to a layer other than the base layer that constitutes the outermost layer on the attachment side of the decorative film to improve adhesion to the resin molded body. The resin constituting the seal layer of the decorative film of the present invention can be selected from general thermoplastic resins, for example, polyolefins such as polyethylene resins, polypropylene resins, ethylene elastomers, modified polyolefins, styrene elastomers, petroleum resins, etc., and combinations thereof may be used. Examples of modified polyolefins include resins containing polymerization units derived from polar group-containing monomers such as maleic anhydride and polymerization units derived from olefin monomers in any ratio. For example, when the seal layer according to the present invention is a polypropylene resin, the MFR (230 ° C, 2.16 kg load) of the resin is preferably 0.1 g / 10 min or more in terms of adhesion, more preferably 0.4 g / 10 min or more, and even more preferably 2.0 g / 10 min or more. There is no particular limit to the upper limit of the MFR, but it is preferably 100 g / 10 min or less, more preferably 50 g / 10 min or less. By setting the MFR within the above range, good adhesiveness can be obtained.

Figures 8(a) to (c) are explanatory diagrams that show schematic examples of cross sections of an embodiment of a decorative film attached to a resin molded body. In Figures 8(a) to (c), the arrangement of the seal layer (I) and the base layer (II) is specified for ease of understanding, but the layer structure of the decorative film is not limited to these examples. In this specification, the reference numeral 1 in the drawings indicates the decorative film, the reference numeral 2 indicates the base layer (II), the reference numeral 3 indicates the seal layer (I), the reference numeral 4 indicates the surface decorative layer (III), and the reference numeral 5 indicates the resin molded body. Figure 8(a) shows an example in which the decorative film 1 is made of a two-layer film, in which the seal layer (I) 3 is attached to the resin molded body 5, and the base layer (II) 2 is laminated on the seal layer (I) 3. The decorative film 1 in FIG. 8(b) is composed of a seal layer (I) 3, a base layer (II) 2, and a surface layer, with the seal layer (I) 3 attached to the surface of the resin molded body 5, and the base layer (II) 2 and the surface layer laminated in this order on top of the seal layer (I) 3. The decorative film 1 in FIG. 8(c) is composed of a seal layer (I) 3, a base layer (II) 2, and a surface decorative layer (III) 4, with the seal layer (I) 3 attached to the surface of the resin molded body 5, and the base layer (II) 2 and the surface decorative layer (III) 4 laminated in this order on top of the seal layer (I) 3.

Each layer may contain additives other than the hindered amine light stabilizer and/or UV absorber, fillers, colorants, other resin components, etc. The total amount of the other additives, fillers, colorants, other resin components, etc. is preferably 50% by weight or less based on the resin composition. As the other additives, the additives described above can be used.

The resin composition that makes up each layer can be produced by melt-kneading resin, weatherproofing agent, other additives, filler, colorant, other resin components, etc.; by dry-blending other resin components with a melt-kneaded mixture of resin, weatherproofing agent, other additives, filler, colorant, etc.; or by dry-blending a master batch in which resin and other resin components, weatherproofing agent, other additives, filler, colorant, etc. are dispersed in high concentration in a carrier resin.

The decorative film of the present invention preferably has a thickness of about 20 μm or more, more preferably about 50 μm or more, and even more preferably about 80 μm or more. By making the thickness of the decorative film at or above this value, the effect of imparting design is improved, and the stability during molding is also improved, making it possible to obtain a better decorated molded body. On the other hand, the thickness of the decorative film is preferably about 2 mm or less, more preferably about 1.2 mm or less, and even more preferably about 0.8 mm or less. By making the thickness of the decorative film at or below this value, the time required for heating during thermoforming is shortened, thereby improving productivity and making it easier to trim unnecessary parts.

[Manufacturing of decorative film]
The decorative film of the present invention can be produced by various known molding methods.
For example, in the case of a multi-layer film, the methods include a co-extrusion molding method, a thermal lamination method in which one layer is laminated on one side of a layer previously extruded by applying heat and pressure to another layer, a dry lamination method and a wet lamination method in which layers are laminated via an adhesive, and an extrusion lamination method and a sand lamination method in which a resin is melt-extruded on one side of a layer previously extruded by extrusion, etc. As an apparatus for forming the decorative film, a known co-extrusion T-die molding machine or a known lamination molding machine can be used. Among these, a co-extrusion T-die molding machine is preferably used from the viewpoint of productivity.

Methods for cooling the molten decorative film extruded from the die include contacting the molten decorative film with a single cooling roll via air discharged from an air knife unit or air chamber unit, and cooling by pressing with multiple cooling rolls.

When imparting gloss to the decorative film of the present invention, a method is used in which a mirror-finished cooling roll is transferred onto the design surface of the decorative film to give it a mirror finish.

Furthermore, the surface of the decorative film of the present invention may have a textured pattern. Such decorative films can be produced by a method in which the molten resin extruded from a die is directly pressed between a roll with a textured pattern and a smooth roll to transfer the textured pattern to the surface, or by a method in which a smooth film is pressed between a heated roll with a textured pattern and a smooth cooled roll to transfer the texture to the surface. Examples of textured patterns include matte, animal skin, hairline, and carbon patterns.

The decorative film of the present invention may be heat-treated after deposition. Examples of heat-treatment methods include heating with a heated roll, heating with a heating furnace or far-infrared heater, and blowing hot air.

[Decorative molding]
In the present invention, the resin molded article (the object of decoration) to be decorated may be any of various molded articles (hereinafter sometimes referred to as "substrate") made of preferably a thermoplastic resin, more preferably a polyolefin resin, and even more preferably a polypropylene resin or a polypropylene resin composition. The molding method for the molded article is not particularly limited, and examples thereof include injection molding, blow molding, press molding, and extrusion molding.

As the base resin of the polypropylene-based resin and polypropylene-based resin composition of the resin molded body to be decorated, various types of resins can be selected that use various known propylene monomers as the main raw material, such as propylene homopolymer (homopolypropylene), propylene-α-olefin copolymer, or propylene block copolymer. In addition, as long as the effect of the present invention is not impaired, it may contain a filler such as talc to impart rigidity, or an elastomer to impart impact resistance. In addition, as with the polypropylene-based resin composition that can constitute the above-mentioned decorative film, it may contain additive components including weathering agents and other resin components.

The decorative film of the present invention is applied to various three-dimensionally formed molded bodies, and as the VOCs contained in the paint and adhesives are significantly reduced, the decorative molded bodies can be suitably used as automobile parts, home appliances, vehicles (railroads, etc.), building materials, daily necessities, etc.

[Production of Decorative Molded Body]
The manufacturing method of the decorated molded body of the present invention is characterized by including the steps of preparing the above-mentioned decorative film, preparing a resin molded body, setting the resin molded body and the decorative film in a chamber box that can be depressurized, reducing the pressure inside the chamber box, heating and softening the decorative film, pressing the decorative film against the resin molded body, and returning the pressure inside the depressurized chamber box to atmospheric pressure or pressurizing it.

The manufacturing method for decorated molded bodies of the present invention makes it possible to obtain beautiful decorated molded bodies with good reproducibility of textures such as grain, without any air being trapped between the decorative film and the resin molded body.

Three-dimensional decorative thermoforming involves the basic steps of placing a resin molded body and decorative film in a chamber box that can be depressurized, heating and softening the film while the chamber box is depressurized, pressing the film against the resin molded body, and returning the pressure inside the chamber box to atmospheric pressure or applying pressure to attach the decorative film to the surface of the resin molded body, and the film is attached under reduced pressure. This makes it possible to obtain a beautiful decorated molded body without air pockets. In the manufacturing method of the present invention, any known technology can be used as long as the equipment and conditions are suitable for three-dimensional decorative thermoforming.

In other words, the chamber box may contain the resin molding, the decorative film, the mechanism for pressing them together, the device for heating the decorative film, etc., all in one place, or it may be multiple units separated by the decorative film.

The mechanism for pressing the resin molding against the decorative film may be of any type, including one that moves the resin molding, one that moves the decorative film, or one that moves both.
More specifically, typical molding methods will be exemplified below.

The following describes an example of how to attach a decorative film to a resin molded body using a three-dimensional decorative thermoforming machine, with reference to the figures.

As shown in FIG. 2, the three-dimensional decorative thermoforming machine of this embodiment is equipped with upper and lower chamber boxes 11 and 12, and the decorative film 1 is thermoformed in the two chamber boxes 11 and 12. A vacuum circuit (not shown) and an air circuit (not shown) are respectively piped to the upper and lower chamber boxes 11 and 12.

A jig 13 for fixing the decorative film 1 is provided between the upper and lower chamber boxes 11 and 12. A table 14 that can be raised and lowered is installed in the lower chamber box 12, and the resin molded body (object to be decorated) 5 is set on this table 14 (either directly or via a jig, etc.). A heater 15 is built into the upper chamber box 11, and the decorative film 1 is heated by this heater 15.

A commercially available molding machine (e.g., the NGF series manufactured by Fuse Vacuum Co., Ltd.) can be used as this type of three-dimensional decorative thermoforming machine.

As shown in FIG. 3, first, with the upper and lower chamber boxes 11 and 12 open, the resin molded body 5 is placed on the table 14 in the lower chamber box 12, and the table 14 is lowered. Next, the decorative film 1 is set on the film fixing jig 13 between the upper and lower chamber boxes 11 and 12 so that the adhesive surface faces the resin molded body 5.

As shown in FIG. 4, the upper chamber box 11 is lowered, the upper and lower chamber boxes 11 and 12 are joined together to close the inside of the boxes, and then the inside of each chamber box 11 and 12 is placed in a vacuum suction state, and the decorative film 1 is heated by the heater 15.

After the decorative film 1 is heated and softened, as shown in FIG. 5, the table 14 in the lower chamber box 12 is raised while the upper and lower chamber boxes 11 and 12 are in a vacuum suction state. The decorative film 1 is pressed against the resin molding 5 to cover it. Furthermore, as shown in FIG. 6, the upper chamber box 11 is opened to atmospheric pressure or compressed air is supplied from a compressed air tank, so that the decorative film 1 is adhered to the resin molding 5 with even greater force.

Next, the upper and lower chamber boxes 11 and 12 are opened to atmospheric pressure, and the decorative molded body 6 is removed from the lower chamber box 12. Finally, the unnecessary edges of the decorative film 1 around the decorative molded body 6 are trimmed, as shown in FIG. 7.

[Molding condition]
The pressure inside the chamber boxes 11 and 12 may be reduced to such an extent that no air pockets are generated, and the pressure inside the chamber boxes is 10 kPa or less, preferably 3 kPa or less, and more preferably 1 kPa or less.

In addition, in the two chamber boxes 11 and 12 divided into upper and lower parts by the decorative film 1, the pressure inside the chamber box on the side where the resin molding 5 and decorative film 1 are attached needs to be within this range, and drawdown of the decorative film 1 can be suppressed by changing the pressure in the upper and lower chamber boxes 11 and 12.

The heating of the decorative film 1 is controlled by the heater temperature (output) and heating time. In addition, the surface temperature of the film can be measured with a thermometer such as a radiation thermometer to provide an indication of appropriate conditions.

In the present invention, in order to attach the decorative film 1 to the resin molded body 5, it is necessary that the surface of the resin molded body 5 and the decorative film 1 are sufficiently softened or melted.

For this reason, the heater temperature must be higher than the melting temperature of the resin that constitutes the resin molding 5 and the resin that constitutes the decorative film 1. In the case of a polypropylene-based decorative film, the heater temperature is preferably 160°C or higher, more preferably 180°C or higher, and most preferably 200°C or higher.

The higher the heater temperature, the shorter the time required for heating; however, before the inside of the decorative film 1 (or the side opposite the heater if the heater is installed on only one side) is sufficiently heated, the temperature on the heater side may become too high, resulting in poor formability and thermal degradation of the resin. Therefore, the heater temperature is preferably 500°C or less, more preferably 450°C or less, and most preferably 400°C or less.

The appropriate heating time varies depending on the heater temperature, but it is necessary that the decorative film is sufficiently softened or melted. In the case of polypropylene-based decorative films, it is preferable that the decorative film is heated at least until it starts to return to its original tension, known as springback. That is, when a polypropylene-based decorative film is heated by a heater, it expands thermally from a solid state when heated, sagging once as the crystals melt, and as the crystal melting progresses throughout, the molecules relax, temporarily returning to their original tension, a phenomenon known as springback, and then it sags under its own weight. However, after springback, the film's crystals are completely melted and the molecules are sufficiently relaxed, so that the film has good thermoformability and sufficient adhesive strength.

On the other hand, if the heating time is too long, the film may sag under its own weight or become deformed due to the pressure difference between the upper and lower chamber boxes, so it is preferable to keep the heating time to less than 120 seconds after the springback is complete.

When decorating a molded body with a complex shape having irregularities or when achieving higher adhesive strength, it is preferable to supply compressed air when adhering the decorative film to the substrate. The pressure in the upper chamber box when compressed air is introduced is 150 kPa or more, preferably 200 kPa or more, and more preferably 250 kPa or more. There is no particular upper limit, but if the pressure is too high, there is a risk of damaging the equipment, so it is 450 kPa or less, preferably 400 kPa or less.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

1. Measurement Method of Various Physical Properties (i) Fogging Test The following fogging test was performed according to a method in accordance with ISO 6452. After that, the haze value (HAZE) of the glass plate covering the mouth of the sample bottle was measured using a haze meter (NDH5000 type, manufactured by Nippon Denshi Kogyo Co., Ltd.), and the amount of change in the haze value before and after the fogging test was calculated using the following formula.
Change in haze value after fogging test=haze value of glass plate after fogging test−haze value of glass plate before fogging test The haze value of the glass plate before the fogging test was 0.23.
<Fogging test>
1 g (±0.01 g) of the hindered amine light stabilizer or ultraviolet absorber was placed in a glass sample bottle (inner diameter 83 mm, height 190 mm), the sample bottle was covered with a glass plate (thickness 3.0 mm), and heated at 150° C. for 1 hour to cause fogging on the glass plate. The fogging tester used was a Windscreen Fogging Tester WF-2 (manufactured by Suga Test Instruments Co., Ltd.). The glass sample bottle and glass plate used were those provided by Suga Test Instruments Co., Ltd.

(ii) Melt Flow Rate (MFR)
The measurement was performed at 230° C. under a load of 2.16 kg in accordance with ISO 1133:1997 Conditions M. The unit is g/10 min.

(iii) Strain hardening degree λ
The strain hardening degree λ was obtained by the method described above. At this time, η* (0.01) used as the value of shear viscosity and ηe (3.5) used as the value of extensional viscosity were measured by the following method. The samples used in the measurement were pressed for 1 hour under conditions of a temperature of 180° C. and a pressure of 10 MPa to form flat plates with thicknesses of 0.7 mm and 2 mm. The 0.7 mm sample was used for the extensional viscosity measurement, and the 2 mm sample was used for the dynamic frequency sweep experiment.

(iii-1) Shear viscosity η * (0.01)
Dynamic frequency sweep experiments were performed using ARES manufactured by Rheometric Scientific. A parallel disk with a diameter of 25 mm was used for the measurement geometry. Measurements were performed using the device control software TA Orchestrator in the measurement mode Dynamic Frequency Sweep Test. The sample used was a press molded body with a thickness of 2 mm produced by the above method. The measurement temperature was 180°C. The angular frequency ω was measured at five points per digit at equal intervals between 0.01 and 100 rad/s on a logarithmic scale.
The complex viscosity η* (0.01) [unit: Pa s] at ω = 0.01 rad/s is used as an index showing the viscosity of the sample at a low shear rate. The complex viscosity η* is calculated from the complex elastic modulus G* [unit: Pa] and ω by η* = G*/ω.

(iii-2) Extensional viscosity ηe (3.5)
Extensional viscosity measurements were performed using an Extensional Viscosity Fixture manufactured by TA Instruments Co., Ltd. on a measurement jig of ARES manufactured by Rheometric Scientific Co., Ltd. Measurements were performed using the device control software TA Orchestrator in the measurement mode Extensional Viscosity Test. The sample used was a test piece with a thickness of 0.7 mm molded by the above method. The width of the test piece was 10 mm and the length was 18 mm. The strain rate was 1.0 s-1, and the measurement temperature was 180 ° C. Other measurement parameters were set as follows.
Sampling Mode: log
Points Per Zone: 200
Solid Density: 0.9
Melt Density: 0.8
Prestretch Rate: 0.05s ^-1
Relaxation after Prestretch: 30 sec
Under these conditions, data is collected for at least 3.7 seconds from the start of measurement. The software obtains time-dependent data on the extensional viscosity. The extensional viscosity value at 3.5 seconds (i.e., strain amount 3.5) of the obtained extensional viscosity curve is taken as ηe (3.5) [unit: Pa s].

(iv) Measurement of branching index g′ at absolute molecular weight Mabs of 1 million:
According to the above-mentioned method, the measurement was carried out using GPC equipped with a light scattering meter and a viscometer as detectors, and the branching index g' was determined based on the above-mentioned analysis method.

(v) Detection of long chain branching structure using ^13C -NMR:
According to the above-mentioned method, measurement was carried out using ¹³ C-NMR to determine the presence or absence of a long chain branched structure.

2. Materials used (1) Hindered amine light stabilizer and ultraviolet absorber (A-1): Hindered amine light stabilizer (change in haze value after fogging test = 3.78, molecular weight = about 3000), product name "Chimassorb 944" manufactured by BASF Corporation
(A-2): Hindered amine light stabilizer (change in haze value after fogging test = 5.13, molecular weight = about 791), manufactured by ADEKA Corporation, product name "LA-57"
(A-3): Hindered amine light stabilizer (change in haze value after fogging test = 3.98, molecular weight = about 1900), manufactured by ADEKA Corporation, product name "LA-68"
(A-4): Hindered amine light stabilizer (change in haze value after fogging test = 49.59, molecular weight = 480), manufactured by BASF Corporation, product name "Tinuvin 770"
(A-5): UV absorber (change in haze value after fogging test = 22.12, molecular weight = 659), manufactured by ADEKA Corporation, trade name "ADEKA STAB LA-31G"

(2) Polypropylene-based resin The following polypropylene-based resin was used.
(B-1): Propylene homopolymer having no long chain branches (MFR = 0.4 g/10 min, strain hardening λ = 1.0), manufactured by Japan Polypropylene Corporation, product name "Novatec (registered trademark) EA9", branching index g' = 1.0 at absolute molecular weight Mabs of 1 million, confirmed to have no long chain branching structure by ^13C -NMR measurement.
(B-1-1): A polypropylene resin composition (MFR=0.4 g/10 min) obtained by blending 100 parts by weight of a polypropylene resin (B-1) with 0.2 parts by weight of a hindered amine light stabilizer (A-1).
(B-1-2): A polypropylene resin composition (MFR=0.4 g/10 min) obtained by blending 100 parts by weight of a polypropylene resin (B-1) with 0.2 parts by weight of a hindered amine light stabilizer (A-2).
(B-1-3): A polypropylene resin composition (MFR=0.4 g/10 min) obtained by blending 100 parts by weight of a polypropylene resin (B-1) with 0.2 parts by weight of a hindered amine light stabilizer (A-3).
(B-1-4): A polypropylene resin composition (MFR=0.4 g/10 min) obtained by blending 100 parts by weight of a polypropylene resin (B-1) with 0.2 parts by weight of a hindered amine light stabilizer (A-4).
(B-1-5): A polypropylene resin composition (MFR=0.4 g/10 min) obtained by blending 100 parts by weight of a polypropylene resin (B-1), 0.1 parts by weight of a hindered amine light stabilizer (A-1), and 0.2 parts by weight of an ultraviolet absorber (A-5).
(B-2): Propylene homopolymer having long chain branches produced by a macromer copolymerization method, manufactured by Japan Polypropylene Corporation, product name "WAYMAX (registered trademark) MFX8", MFR = 1.0 g/10 min, strain hardening degree λ = 9.7, branching index g' = 0.89 at absolute molecular weight Mabs of 1 million, confirmed to have a long chain branching structure by ¹³ C-NMR measurement.
(B-2-1) A polypropylene resin composition (MFR=1.0 g/10 min) prepared by blending 100 parts by weight of a polypropylene resin (B-2) with 0.2 parts by weight of a hindered amine light stabilizer (A-1).
(B-3): Propylene homopolymer having no long chain branches (MFR = 10 g/10 min, strain hardening λ = 1.0), manufactured by Japan Polypropylene Corporation, product name "Novatec (registered trademark) FA3KM", branching index g' = 1.0 at absolute molecular weight Mabs of 1 million, confirmed to have no long chain branching structure by ¹³ C-NMR measurement.
(B-3-1) A polypropylene resin composition (MFR=10 g/10 min) obtained by blending 100 parts by weight of a polypropylene resin (B-3) with 0.2 parts by weight of a hindered amine light stabilizer (A-1).
(B-4): Propylene-α-olefin copolymer having no long chain branches (MFR = 7.0 g/10 min, strain hardening λ = 1.0), manufactured by Japan Polypropylene Corporation, product name "Wintech (registered trademark) WFX4M", branching index g' = 1.0 at absolute molecular weight Mabs of 1 million, confirmed to have no long chain branching structure by ^13C -NMR measurement.

(3) Other Thermoplastic Resins The following thermoplastic resins were used.
(C-1): Maleic anhydride modified polyolefin (MFR=7.0 g/10 min), manufactured by Mitsubishi Chemical Corporation, trade name "Modic AP (registered trademark) F534A"

3. Production of resin molded body (substrate) Using propylene homopolymer (D-1) (MFR = 40 g/10 min, Tm = 165°C, manufactured by Japan Polypropylene Corporation, product name "Novatec (registered trademark) MA04H"), an injection molded body was obtained by the following method.
Injection molding machine: Toshiba Machine Co., Ltd. "IS100GN", mold clamping pressure 100 tons Cylinder temperature: 200°C
Mold temperature: 40°C
Injection mold: width x height x thickness = 120 mm x 120 mm x 3 mm flat plate Conditioning: kept in a constant temperature and humidity room at a temperature of 23°C and a humidity of 50% RH for 5 days

Example 1
・Manufacture of decorative film A two-type two-layer T die with a lip opening of 0.8 mm and a die width of 400 mm was used, to which a base layer extruder-1 with a diameter of 40 mm (diameter) and a seal layer extruder-2 with a diameter of 30 mm (diameter) were connected. A polypropylene resin (B-1-1) was charged into the base layer extruder-1, and a polypropylene resin (B-1) was charged into the seal layer extruder-2, respectively, and melt extrusion was performed under the conditions of a resin temperature of 240 ° C., a discharge rate of the base layer extruder-1 of 12 kg / h, and a discharge rate of the seal layer extruder-2 of 4 kg / h. The melt-extruded film was cooled and solidified while being pressed with an air knife so that the seal layer was in contact with the first roll rotating at 30 ° C. and 3 m / min, to obtain a two-layer unstretched film in which a base layer having a thickness of 150 μm and a seal layer having a thickness of 50 μm were laminated.

Three-dimensional decorative thermoforming "NGF-0406-SW" manufactured by Fuse Vacuum Co., Ltd. was used as a three-dimensional decorative thermoforming device. As shown in Figures 2 to 7, the decorative film 1 was cut out to a width of 250 mm x length of 350 mm so that the seal layer faces the substrate and the longitudinal direction is the MD direction of the film, and set in a film fixing jig 13 with an opening size of 210 mm x 300 mm. The resin molded body (substrate) 5 was attached via "Nicetack NW-K15" manufactured by Nichiban Co., Ltd. on a sample installation table with a height of 20 mm installed on a table 14 located below the film fixing jig 13. The film fixing jig 13 and the table 14 were installed in the chamber boxes 11 and 12, and the chamber boxes were closed to seal the chamber boxes 11 and 12. The chamber box is divided into upper and lower parts via the decorative film 1. The upper and lower chamber boxes 11 and 12 were suctioned by vacuum, and in a state in which the pressure was reduced from atmospheric pressure (101.3 kPa) to 1.0 kPa, the far-infrared heater 15 installed on the upper chamber box 11 was started at 80% output to heat the decorative film 1. Vacuum suction was continued during heating, and the pressure was finally reduced to 0.1 kPa. After the decorative film 1 was heated and temporarily sagged, and then the springback phenomenon in which the film returned to tension was completed, the film was heated for another 30 seconds, and the table 14 installed in the lower chamber box 12 was moved upward to press the resin molded body (base) 5 against the decorative film 1, and immediately after that, compressed air was sent in so that the pressure in the upper chamber box 11 was 270 kPa to bring the resin molded body (base) 5 and the decorative film 1 into close contact with each other. In this way, a three-dimensionally decorated thermoformed product 6 in which the decorative film 1 was attached to the upper and side surfaces of the resin molded body (base) 5 was obtained.

Example 2
A three-dimensionally decorated thermoformed product was obtained in the same manner as in Example 1, except that in the production of the decorative film of Example 1, the polypropylene-based resin used in the base layer was changed to the polypropylene-based resin (B-1-2).

Example 3
A three-dimensionally decorated thermoformed product was obtained in the same manner as in Example 1, except that in the production of the decorative film of Example 1, the polypropylene-based resin used in the base layer was changed to the polypropylene-based resin (B-1-3).

Example 4
A three-dimensionally decorated thermoformed product was obtained in the same manner as in Example 1, except that in the production of the decorative film of Example 1, the polypropylene-based resin used in the base layer was changed to the polypropylene-based resin (B-1-5).

Example 5
In the production of the decorative film of Example 1, a three-dimensionally decorated thermoformed product was obtained in the same manner as in Example 1, except that the polypropylene-based resin used in the base layer was changed to a polypropylene-based resin (B-2-1).

Example 6
In the production of the decorative film, a three-type three-layer T-die with a lip opening of 0.8 mm and a die width of 400 mm was used, to which a surface layer extruder-3 with a diameter of 30 mmφ, a base layer extruder-1 with a diameter of 40 mmφ, and a seal layer extruder-2 with a diameter of 30 mmφ were connected. A polypropylene-based resin (B-3-1) was charged into the surface layer extruder-3, a polypropylene-based resin (B-1-1) was charged into the base layer extruder-1, and a polypropylene-based resin (B-1) was charged into the seal layer extruder-2, and melt extrusion was performed under the conditions of a resin temperature of 240°C, a discharge rate of 4 kg/h for the surface layer extruder-3, a discharge rate of 8 kg/h for the base layer extruder-1, and a discharge rate of 4 kg/h for the seal layer extruder-2.
The melt-extruded film was cooled and solidified while being pressed with an air knife so that the seal layer was in contact with a first roll rotating at 30°C and 3 m/min, to obtain a three-layer unstretched film laminated with a 50 μm-thick surface layer, a 100 μm-thick base layer, and a 50 μm-thick seal layer.

A three-dimensionally decorated thermoformed product was obtained in the same manner as in Example 1, except that the unstretched film obtained in the above decorative film production was used.

Example 7
In the production of the decorative film of Example 1, a three-dimensionally decorated thermoformed product was obtained in the same manner as in Example 1, except that the polypropylene-based resin used in the seal layer was changed to polypropylene-based resin (B-4).

Example 8
In the production of the decorative film of Example 1, a three-dimensionally decorated thermoformed product was obtained in the same manner as in Example 1, except that the polypropylene resin used in the seal layer was changed to a maleic anhydride modified polyolefin (C-1).

Comparative Example 1
A three-dimensionally decorated thermoformed product was obtained in the same manner as in Example 1, except that in the production of the decorative film of Example 1, the polypropylene-based resin used in the base layer was changed to the polypropylene-based resin (B-1).

Comparative Example 2
A three-dimensionally decorated thermoformed product was obtained in the same manner as in Example 1, except that in the production of the decorative film of Example 1, the polypropylene-based resin used in the base layer was changed to the polypropylene-based resin (B-1-4).

[Weather resistance evaluation]
For the three-dimensionally decorated thermoformed products obtained in Examples 1 to 8 and Comparative Examples 1 and 2, the flat plate samples after three-dimensionally decorated thermoforming were held at 23°C and 50% RH for 48 hours, and then test pieces of 30 mm length and 70 mm width were cut out from the flat plate, and 504 MJ xenon arc lamp light was irradiated onto the decorative film side of the decorative molded body under conditions of a black panel temperature of 89°C, humidity of 50%, and irradiance of 100 W/ ^m2 using an Atlas Tester Ci65AW manufactured by Toyo Seiki Seisakusho Co., Ltd. Light irradiation was also performed under the same conditions for the decorative film before three-dimensional decorative molding. The surface of the test piece was observed under a microscope at a magnification of 20 times every 24 hours, and the time until fine cracks appeared on the surface was defined as the "weather resistance time". The rate of decrease in weather resistance was evaluated according to the following criteria.
◯: The weather resistance time of the flat sample after three-dimensional decorative thermoforming is reduced by less than 20% compared to the weather resistance time of the decorative film before three-dimensional decorative molding.
×: The weather resistance time of the flat sample after three-dimensional decorative thermoforming is reduced by 20% or more compared to the weather resistance time of the decorative film before three-dimensional decorative forming.

The layer structure and weather resistance evaluation results of the decorative films of Examples 1 to 8 and Comparative Examples 1 and 2 are shown in Table 1.

The decorative molded articles obtained from the decorative films of Examples 1 to 8 had a change in haze value of 40 or less when measured by a method conforming to JIS-K7136 on a glass plate after a fogging test was performed by a method conforming to ISO6452 for the hindered amine-based light stabilizer and/or ultraviolet absorber used, so the hindered amine-based light stabilizer and/or ultraviolet absorber did not volatilize from the decorative film during decorative molding, and the obtained decorative molded articles maintained their weather resistance.

On the other hand, the decorative film of Comparative Example 1, in which none of the layers contained a hindered amine-based light stabilizer and/or an ultraviolet absorber, had poor weather resistance for the decorative film and the decorative molded article. In the decorative film of Comparative Example 2, in which the change in haze value measured by a method conforming to JIS-K7136 on the glass plate after a fogging test by a method conforming to ISO6452 exceeded 40 for the hindered amine-based light stabilizer used, the hindered amine-based light stabilizer volatilized during decorative molding, and the resulting decorative molded article had a significant decrease in weather resistance.

The decorative film of the present invention and the method for manufacturing a decorated molded body using the same can be used for three-dimensional decorated molded bodies and their manufacture.

1 Decorative film 2 Base layer (II)
3. Sealing layer (I)
4. Surface decorative layer (III)
5. Resin molded body (decoration object, base body)
6 Decorative molded body 11 Upper chamber box 12 Lower chamber box 13 Jig 14 Table 15 Heater

Claims (7)

A resin composition for decorative films, comprising a polypropylene resin having a long-chain branched structure obtained by a macromer copolymerization method and a hindered amine light stabilizer , wherein the polypropylene resin has a branching index g' of 0.75 or more and 0.96 or less when the absolute molecular weight Mabs is 1,000,000, and the hindered amine light stabilizer satisfies the following requirements:
Requirement: After carrying out the fogging test described below using a method in accordance with ISO 6452, the change in haze value of the glass plate measured using a method in accordance with JIS-K7136 is 40 or less.
<Fogging test> 1 g (±0.01 g) of a hindered amine light stabilizer is placed in a glass sample bottle, the sample bottle is covered with a glass plate, and the glass plate is heated at 150° C. for 1 hour to generate fogging on the glass plate. The resin composition according to claim 1, wherein the molecular weight of the hindered amine light stabilizer is 490 g/mol or more. The resin composition according to claim 1 or 2, in which the melt flow rate (MFR) (temperature 230°C, load 2.16 kg) is 0.1 to 40 g/10 min and the strain hardening degree λ is 1.1 or more. A decorative film comprising a layer made of the resin composition according to any one of claims 1 to 3. A decorative film comprising a substrate layer made of the resin composition according to any one of claims 1 to 3. A decorative film comprising a surface layer made of the resin composition according to any one of claims 1 to 3. A method for manufacturing a decorated molded article, comprising bonding the decorative film according to any one of claims 4 to 6 and a molded article made of a polypropylene-based resin composition by three-dimensional decorative thermoforming.