Decorated three-dimensional structure and method for producing the same

Abstract

To provide a three-dimensional structure which is decorated with a fiber assembly containing carbon fibers and is excellent in aesthetic appearance.SOLUTION: The decorated three-dimensional structure includes: a three-dimensional structure; a first adhesive layer laminated on a surface of the three-dimensional structure; a reinforcing fiber layer laminated on the first adhesive layer, containing carbon fibers, and having voids formed therein; a second adhesive layer laminated on the reinforcing fiber layer; and a layer of a thermoplastic polyurethane resin composition laminated on the second adhesive layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a decorated three-dimensional structure and a method for manufacturing the same. [Background technology]

[0002] Fiber-reinforced resin is a composite material made by mixing fibers such as carbon fiber and aramid fiber with resin to increase its strength. Due to its properties, fiber-reinforced resin is expected to be used in automobile components and housing equipment components, for example.

[0003] Among fiber-reinforced resins, resin-reinforced sheets containing carbon fiber fabrics in particular have excellent aesthetic appeal, and are therefore expected to be used as decorative skin materials for decorating three-dimensional structures such as automobile door trims and miscellaneous items (such as small storage compartments).

[0004] A known method for manufacturing a three-dimensional structure using a fiber-reinforced resin sheet containing woven carbon fiber fabric is to laminate a fiber-reinforced resin sheet containing woven carbon fiber fabric (carbon prepreg) and a transparent resin sheet in a mold and press-molding the laminate in the mold (e.g., Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 157894 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-208419 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to use a fiber-reinforced resin sheet containing woven carbon fiber fabric as a decorative skin material, the fiber-reinforced resin sheet must be able to deform to conform to the three-dimensional structure, be free from wrinkles or lifting, and not impair the appearance.

[0007] However, when a fiber-reinforced resin sheet containing the above-mentioned carbon fiber fabric is bonded to a three-dimensional structure, there is a problem that wrinkles and lifting are likely to occur. Therefore, it has been very difficult to manufacture a three-dimensional structure decorated with carbon fiber fabric (hereinafter referred to as a decorated three-dimensional structure) that is free from wrinkles and lifting and has a good appearance.

[0008] The present invention has been made in view of the above-mentioned problems, and provides a three-dimensional structure that is decorated with a fiber aggregate containing carbon fiber and has an excellent appearance, and a method for manufacturing the same. [Means for solving the problem]

[0009] The present invention relates to the following decorated three-dimensional structure and a method for manufacturing the same.

[0010] [1] A decorated three-dimensional structure comprising: a three-dimensional structure; a first adhesive layer laminated on a surface of the three-dimensional structure; a reinforced fiber layer laminated on the first adhesive layer, the reinforced fiber layer containing carbon fiber and having voids formed therein; a second adhesive layer laminated on the reinforced fiber layer; and a layer of a thermoplastic polyurethane resin composition laminated on the second adhesive layer. [2] A method for manufacturing a decorated three-dimensional structure, comprising: a first step of bonding a three-dimensional structure and a fiber aggregate containing carbon fiber together via a first adhesive; and a second step of bonding the fiber aggregate bonded to the three-dimensional structure to a sheet of a thermoplastic polyurethane resin composition via a second adhesive at a temperature of 115°C or higher under reduced pressure. [3] In the second step, a laminate of a sheet of a thermoplastic polyurethane resin composition and the second adhesive is prepared, and the second adhesive of the laminate is attached to the fiber aggregate. This is a method for producing a decorated three-dimensional structure as described in [2]. [4] The method for manufacturing a decorated three-dimensional structure according to [2] or [3], wherein in the second step, the bonding is carried out at a temperature of 120°C or higher and 135°C or lower. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a three-dimensional structure that is decorated with a fiber aggregate containing carbon fiber and has an excellent appearance, and a method for manufacturing the same. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the configuration of a decorated three-dimensional structure according to one embodiment of the present invention. [Figure 2] 2A to 2E are schematic cross-sectional views showing a method for manufacturing a decorated three-dimensional structure according to one embodiment of the present invention. [Figure 3] 3A and 3B are schematic cross-sectional views showing a method for manufacturing a decorated three-dimensional structure according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present inventors have thoroughly investigated the cause of wrinkles and bubbles that occur when a fiber-reinforced resin sheet containing woven carbon fiber fabric is attached to a three-dimensional structure. As a result, they have found that this is due to the fact that not only are the carbon fibers themselves difficult to stretch, but also that the fiber-reinforced resin sheet containing woven carbon fiber fabric is difficult to stretch to fit the shape of the three-dimensional structure because the carbon fibers are solidified with resin, making it difficult for the fibers to move.

[0014] In contrast, in the present invention, 1) a fiber assembly that is not impregnated with resin is used instead of a fiber-reinforced resin sheet, and the three-dimensional structure and the fiber assembly are bonded together via an adhesive layer (first adhesive layer), which makes it possible to make the fiber assembly less prone to wrinkles.

[0015] It is also desirable to cover the surface of the fiber assembly with a transparent thermoplastic polyurethane resin sheet from the viewpoint of protecting the surface of the carbon fiber fabric, and from the viewpoint that the carbon fiber fabric does not melt when heated over a relatively wide temperature range and is easily converted into a rubbery state, making it suitable for TOM molding, etc. However, when a thermoplastic polyurethane resin sheet is directly attached to the fiber assembly, the sheet is difficult to stretch, and wrinkles may occur, or air bubbles may remain in the carbon fiber fabric without being expelled.

[0016] In contrast, the present invention further provides 2) bonding the fiber assembly and the thermoplastic polyurethane resin sheet via an adhesive layer (second adhesive layer), which eliminates the need to excessively heat the thermoplastic polyurethane resin sheet when bonding the sheet, thereby preventing wrinkles from forming in the sheet and air bubbles from remaining between the sheet and the fiber assembly.

[0017] In this way, the combination of 1) and 2) above can prevent wrinkles from forming in the fiber aggregate or the thermoplastic polyurethane resin sheet, and prevent air bubbles from remaining between the sheet and the fiber aggregate, thereby enabling the production of a three-dimensional structure with excellent aesthetics.

[0018] That is, the decorated three-dimensional structure of the present invention comprises, in this order, a three-dimensional structure, a first adhesive layer, a reinforced fiber layer containing carbon fiber and having voids formed therein, a second adhesive layer, and a layer of a thermoplastic polyurethane resin composition.

[0019] A decorated three-dimensional structure and a method for manufacturing the same according to one embodiment of the present invention will be described below.

[0020] 1. Decorated three-dimensional structure FIG. 1 is a schematic cross-sectional view showing the configuration of a decorated three-dimensional structure 10 according to one embodiment of the present invention. 1, the decorated three-dimensional structure 10 includes a three-dimensional structure 11, and decoration is added to the surface of the three-dimensional structure 11. Specifically, the decorated three-dimensional structure 10 includes, in this order, the three-dimensional structure 11, a first adhesive layer 12, a reinforcing fiber layer 13, a second adhesive layer 14, and a layer 15 of a thermoplastic polyurethane resin composition.

[0021] 1-1. Three-dimensional structure 11 The three-dimensional structure is a core material (object to be decorated) that forms a three-dimensional shape. The material constituting the three-dimensional structure is not particularly limited, and may be a resin material such as a thermoplastic resin, or a metal material. For example, the three-dimensional structure may be any of various molded objects having a three-dimensional shape. The three-dimensional structure may contain, for example, ABS resin (acrylonitrile butadiene styrene copolymer resin), polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, or polyvinyl acetate, and preferably contains ABS resin. The size of the three-dimensional structure is not particularly limited, and may be, for example, 1 to 5 cm in height, 5 to 25 cm in width, and 5 to 25 cm in depth, or 50 to 300 cm in height, 50 to 300 cm in width, and 50 to 300 cm in depth.

[0022] 1-2.First adhesive layer 12 The first adhesive layer is disposed on the three-dimensional structure and bonds the three-dimensional structure to the reinforcing fiber layer. The type of adhesive contained in the first adhesive layer is not particularly limited, and known adhesives such as acrylic adhesives, rubber adhesives, silicone adhesives, and urethane adhesives can be used. Among these, acrylic adhesives are preferred from the viewpoint of making the fiber aggregate and the thermoplastic polyurethane resin composition layer less likely to wrinkle.

[0023] The thickness of the first adhesive layer is not particularly limited, but is preferably, for example, 10 μm or more and 200 μm or less. When the thickness of the first adhesive layer is 10 μm or more, not only can the three-dimensional structure and the reinforcing fiber layer be better bonded, but also the movement of the fibers when the fiber aggregate is bonded can be more easily alleviated, making the resulting reinforcing fiber layer less likely to wrinkle. When the thickness of the first adhesive layer is 200 μm or less, the three-dimensional shape of the three-dimensional structure can be better maintained. From the same perspective, the thickness of the first adhesive layer is more preferably 30 μm or more and 100 μm or less.

[0024] 1-3. Reinforced fiber layer 13 The reinforcing fiber layer is a fiber layer disposed on the first adhesive layer, containing carbon fibers, and having voids formed therein. In this embodiment, the reinforcing fiber layer is a layer of a fiber assembly containing carbon fibers and not impregnated with resin.

[0025] The fiber aggregate containing the above-mentioned carbon fiber and not impregnated with resin is easy to stretch and the weave is easy to move, unlike conventional prepregs and resin-reinforced resin sheets. Therefore, when the fiber aggregate is bonded, it is easy to make the fiber aggregate conform to the three-dimensional shape of the three-dimensional structure, and the resulting reinforcing fiber layer is less likely to wrinkle. In addition, since the reinforcing fiber layer contains many voids, it can also have good cushioning properties.

[0026] Examples of carbon fibers include pitch-based carbon fibers, polyacrylonitrile (PAN)-based carbon fibers, and rayon-based carbon fibers. PAN-based carbon fibers are preferred. The fiber material may further contain fibers other than carbon fibers, such as aramid fibers, polyethylene terephthalate (PET) fibers, liquid crystal polyester fibers, glass fibers, polyethylene fibers, and cellulose fibers.

[0027] The form of the fiber assembly is not particularly limited, and examples thereof include woven fabrics, knitted fabrics, felts, nonwoven fabrics, and unidirectional materials. The fiber assembly is preferably a woven fabric from the viewpoint of enhancing design. The type of woven fabric is also not particularly limited, and examples thereof include plain weave, twill weave, satin weave, saty weave, and checkered weave. Furthermore, examples of the type of woven fabric include uniaxial weave and multiaxial weave.

[0028] The porosity of the reinforcing fiber layer is not particularly limited, but is preferably 20% or more, and more preferably 25% or more. If the porosity of the reinforcing fiber layer is 30% or more, the fibers can move more easily when the fiber aggregate is bonded, making it possible to make the resulting reinforcing fiber layer less prone to wrinkles. In addition, cushioning properties can be improved, and the feel and texture can be improved. The upper limit of the porosity of the reinforcing fiber layer is not particularly limited, but can be, for example, 40% or less, preferably 35% or less.

[0029] The porosity of the reinforcing fiber layer can be measured by analyzing images obtained by X-ray CT. For example, the 2D reconstructed cross-sectional image can be binarized, and the porosity can be calculated based on the binarized image.

[0030] The thickness of the reinforcing fiber layer is not particularly limited, but is, for example, 50 μm to 1000 μm, preferably 100 μm to 500 μm. When the thickness of the reinforcing fiber layer is 50 μm or more, the design can be further improved. When the thickness of the reinforcing fiber layer is 1000 μm or less, the conformability to a three-dimensional structure can be further improved.

[0031] 1-4.Second adhesive layer 14 The second adhesive layer is disposed on the reinforcing fiber layer and bonds the reinforcing fiber layer to the layer of thermoplastic polyurethane resin composition. The material of the second adhesive layer can be the same as the material of the first adhesive layer.

[0032] The thickness of the second adhesive layer is not particularly limited and may be the same as or different from the thickness of the first adhesive layer. The thickness of the second adhesive layer is preferably, for example, 10 μm or more and 200 μm or less. A thickness of the second adhesive layer of 10 μm or more not only improves adhesion between the reinforcing fiber layer and the layer of the thermoplastic polyurethane resin composition, but also makes it easier to expel air bubbles from the gaps in the reinforcing fiber layer. A thickness of the second adhesive layer of 200 μm or less allows the three-dimensional shape of the three-dimensional structure to be maintained better. From the same viewpoint, the thickness of the second adhesive layer is more preferably 30 μm or more and 100 μm or less.

[0033] 1-5. Thermoplastic polyurethane resin composition layer 15 The layer of the thermoplastic polyurethane resin composition is disposed on the second adhesive layer and protects the reinforcing fiber layer. The layer of the thermoplastic polyurethane resin composition is preferably a transparent layer from the viewpoint of not impairing the visibility of the reinforcing fiber layer. The thermoplastic polyurethane resin composition contains a thermoplastic polyurethane resin.

[0034] 1-5-1.Thermoplastic polyurethane resin The thermoplastic polyurethane resin is a reaction product obtained by reacting a composition containing a polyisocyanate component and a polyol component.

[0035] (Polyisocyanate component) The polyisocyanate component may be any of an aliphatic polyisocyanate, an alicyclic polyisocyanate, an aromatic polyisocyanate, and an araliphatic polyisocyanate.

[0036] Examples of the aliphatic polyisocyanate include aliphatic diisocyanates such as ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), and hexamethylene diisocyanate (HDI).

[0037] Examples of the alicyclic polyisocyanate include monocyclic alicyclic polyisocyanates and polycyclic alicyclic polyisocyanates. Monocyclic alicyclic polyisocyanates are polyisocyanate monomers containing one alicyclic ring per molecule. Examples of monocyclic alicyclic polyisocyanates include monocyclic alicyclic diisocyanates such as 1,4-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, and isophorone diisocyanate. The polycyclic alicyclic polyisocyanate is a polyisocyanate monomer containing two or more alicyclic rings in one molecule. Examples of the polycyclic alicyclic polyisocyanate include norbornene diisocyanate and polycyclic alicyclic diisocyanates such as methylenebis(cyclohexyl isocyanate).

[0038] Examples of aromatic polyisocyanates include aromatic diisocyanates such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), toluidine diisocyanate (TODI), paraphenylene diisocyanate, and naphthalene diisocyanate (NDI).

[0039] Examples of the araliphatic polyisocyanate include araliphatic diisocyanates such as xylylene diisocyanate (XDI) and tetramethyl xylylene diisocyanate (TMXDI).

[0040] In particular, from the viewpoint of further increasing the strength of the layer of the thermoplastic polyurethane resin composition, the polyisocyanate component preferably contains an alicyclic polyisocyanate, more preferably a monocyclic alicyclic polyisocyanate. The monocyclic alicyclic polyisocyanate is preferably 1,4-bis(isocyanatomethyl)cyclohexane and / or 1,3-bis(isocyanatomethyl)cyclohexane, more preferably 1,4-bis(isocyanatomethyl)cyclohexane.

[0041] 1,4-bis(isocyanatomethyl)cyclohexane is classified into cis-1,4-bis(isocyanatomethyl)cyclohexane (also called "cis 1,4 isomer") and trans-1,4-bis(isocyanatomethyl)cyclohexane (also called "trans 1,4 isomer"). The total amount of trans 1,4 isomer and cis 1,4 isomer is 100 mol %.

[0042] 1,4-bis(isocyanatomethyl)cyclohexane preferably contains the trans-1,4 isomer. The content of the trans-1,4 isomer relative to the total moles of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 60 mol% to 99.5 mol%, preferably 70 mol% to 99 mol%, more preferably 75 mol% to 96 mol%, and even more preferably 80 mol% to 90 mol%. When the content of the trans-1,4 isomer is equal to or greater than the lower limit, higher heat resistance can be obtained.

[0043] When the polyisocyanate component contains a monocyclic alicyclic polyisocyanate, the content of the monocyclic alicyclic polyisocyanate is, for example, more than 50 mol%, preferably 70 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and particularly preferably 100 mol%, relative to the total amount of the polyisocyanate component.

[0044] (Polyol component) The polyol component is a compound containing two or more hydroxyl groups in the molecule, and examples of the polyol component include low-molecular-weight polyols and macropolyols.

[0045] The low-molecular-weight polyol is an organic compound having two or more hydroxyl groups in the molecule and a relatively low molecular weight. The molecular weight of the low-molecular-weight polyol is, for example, 40 or more and less than 400, preferably 40 or more and less than 300.

[0046] Examples of low-molecular-weight polyols include dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols. Examples of dihydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of trihydric alcohols include glycerin and trimethylolpropane. Examples of tetrahydric or higher alcohols include pentaerythritol and diglycerin. Examples of low-molecular-weight polyols include polymers obtained by addition polymerization of alkylene (C2-3) oxide with dihydric to tetrahydric alcohols to obtain a number-average molecular weight of less than 400.

[0047] These low molecular weight polyols preferably include dihydric alcohols and trihydric alcohols, and more preferably include dihydric alcohols.

[0048] The macropolyol is a relatively high molecular weight organic compound having two or more hydroxyl groups in the molecule. The number average molecular weight of the macropolyol is, for example, 400 to 5,000, preferably 500 to 3,000, and more preferably 500 to 2,200. When the number average molecular weight of the macropolyol is equal to or less than the upper limit, the transparency and design properties of the layer of the thermoplastic polyurethane resin composition can be further improved. The average number of functional groups (average number of hydroxyl groups) of the macropolyol is, for example, 2 to 6, preferably 2 to 4, and more preferably 2 to 3.

[0049] Examples of the macropolyol include polyether polyol, polyester polyol, polycarbonate polyol, polyurethane polyol, epoxy polyol, vegetable oil polyol, polyolefin polyol, acrylic polyol, and vinyl monomer-modified polyol. Preferred examples of the macropolyol include polyether polyol, polyester polyol, and polycarbonate polyol.

[0050] Examples of polyether polyols include polyoxyalkylene polyols, such as polyoxyalkylene (C2-3) polyols and polytetramethylene ether polyols.

[0051] Examples of polyester polyols include condensation polyester polyols and ring-opening polyester polyols, examples of condensation polyester polyols include adipate polyester polyols and phthalate polyester polyols, and examples of ring-opening polyester polyols include lactone polyester polyols.

[0052] Examples of polycarbonate polyols include ring-opening polymers of ethylene carbonate using the above-mentioned low-molecular-weight polyols as initiators.

[0053] As the macropolyol, polyether polyol is preferred from the viewpoint of heat resistance, and polycarbonate polyol is preferred from the viewpoint of weather resistance.

[0054] Macropolyols can also be classified into crystalline macropolyols and amorphous macropolyols. Crystalline macropolyols are solid macropolyols at 25°C. Amorphous macropolyols are liquid macropolyols at 25°C.

[0055] The macropolyol preferably contains an amorphous macropolyol, which can further increase the flexibility of the layer of the thermoplastic polyurethane resin composition.

[0056] The polyol component can be used alone or in combination of two or more kinds. As the polyol component, a combination of a low molecular weight polyol and a macro polyol is preferably used.

[0057] When a low-molecular-weight polyol and a macro-polyol are used in combination, the content ratio thereof can be appropriately set depending on the purpose and application. For example, it is preferable to use a low-molecular-weight polyol and a macro-polyol in combination so that the hard segment concentration and urethane group concentration of the thermoplastic polyurethane resin are in the ranges described below.

[0058] Specifically, the content of the macropolyol can be, for example, 10 mol% to 80 mol%, preferably 20 mol% to 65 mol%, based on the total amount of the macropolyol and the low-molecular-weight polyol. If the content of the macropolyol is within the above range, the heat resistance, weather resistance, and flexibility of the layer of the thermoplastic polyurethane resin composition can be further improved.

[0059] (Physical properties of thermoplastic polyurethane resin) The hard segment concentration of the thermoplastic polyurethane resin is not particularly limited, but is, for example, 5% by mass to 60% by mass, preferably 8% by mass to 55% by mass, more preferably 11% by mass to 50% by mass, and even more preferably 15% by mass to 40% by mass. When the hard segment concentration of the thermoplastic polyurethane resin is within the above range, the strength of the layer of the thermoplastic polyurethane resin composition can be further increased.

[0060] The urethane group concentration of the thermoplastic polyurethane resin is not particularly limited, but is, for example, 1.0 mmol / g to 8.0 mmol / g, preferably 1.5 mmol / g to 4.5 mmol / g, more preferably 1.7 mmol / g to 3.4 mmol / g, and even more preferably 2.5 mmol / g to 3.0 mmol / g. If the urethane group concentration of the thermoplastic polyurethane resin is within the above range, the strength of the layer of the thermoplastic polyurethane resin composition can be further increased. The urethane group concentration can be calculated by a known method based on the blending recipe (charge) of each component.

[0061] The thermoplastic polyurethane resin preferably satisfies the following formula (1), which indicates the crystallinity of the thermoplastic polyurethane resin. The lower the value of formula (1), the lower the crystallinity, which tends to result in relatively high flexibility and less wrinkling. Equation (1): 0<[heat release amount of urethane group recrystallization peak (mJ / mg) / heat release interval (°C)]<0.85

[0062] The calorific value of the recrystallization peak represented by formula (1) is more than 0 and not more than 0.85, preferably 0.01 or more and 0.45 or less, and more preferably 0.02 or more and 0.20 or less. When the value of formula (1) is within the above range, the flexibility of the layer of the thermoplastic polyurethane resin composition can be further improved.

[0063] In differential scanning calorimetry (DSC), among the peaks that appear during cooling after heating to 270°C, the exothermic peak (recrystallization peak) between 50°C and 180°C is taken as the recrystallization peak of the urethane group, and the peak width is taken as the exothermic range (°C). The heat quantity (enthalpy change) (mJ / mg) at the recrystallization peak is taken as the exothermic value of the recrystallization peak.

[0064] (Synthesis method) As described above, the thermoplastic polyurethane resin can be obtained by reacting a polyisocyanate component with a polyol component. Examples of the reaction method include the one-shot method and the prepolymer method, and the prepolymer method is preferred.

[0065] In the prepolymer method, first, a polyisocyanate component and a macropolyol are polymerized by a known polymerization method to obtain an isocyanate group-terminated prepolymer (prepolymer synthesis step), and then the isocyanate group-terminated prepolymer is reacted with a chain extender to obtain a thermoplastic polyurethane elastomer (chain extension step).

[0066] In the prepolymer synthesis step, the mixing ratio of the polyisocyanate component and the macropolyol is adjusted so that the isocyanate groups of the polyisocyanate component are in excess relative to the hydroxyl groups of the macropolyol. Specifically, the equivalent ratio of the isocyanate groups in the polyisocyanate component to the hydroxyl groups in the macropolyol (isocyanate groups / hydroxyl groups) is, for example, 1.5 to 10, preferably 1.8 to 7, more preferably 2 to 5, and even more preferably 2.5 to 4.5.

[0067] In the chain extension step, the chain extender preferably contains a low-molecular-weight polyol. The blending ratio of the isocyanate-terminated prepolymer and the chain extender is appropriately set. The equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate groups in the isocyanate-terminated prepolymer to the hydroxyl groups in the chain extender (low-molecular-weight polyol) is, for example, 0.75 or more and 1.3 or less, preferably 0.9 or more and 1.2 or less.

[0068] 1-5-2. Other ingredients The thermoplastic polyurethane resin composition may be composed solely of a thermoplastic polyurethane resin, or may contain other components in addition to the thermoplastic polyurethane resin, as necessary. Examples of other components include antioxidants, heat stabilizers, UV absorbers, weather stabilizers, light stabilizers, antiblocking agents, release agents, colorants (pigments, dyes), lubricants, fillers, hydrolysis inhibitors, rust inhibitors, and bluing agents. The content of other components may be, for example, 5% by mass or less based on the thermoplastic polyurethane resin composition.

[0069] 1-5-3. Physical properties of thermoplastic polyurethane resin composition layer The layer of the thermoplastic polyurethane resin composition may be textured to enhance the design. That is, the surface roughness Ra of the layer of the thermoplastic polyurethane resin composition (surface roughness Ra on the side opposite to the side on which the second adhesive layer 14 is disposed) is, for example, preferably 0.7 μm or more and 2.1 μm or less, more preferably 0.8 μm or more and 2.0 μm or less, and even more preferably 0.9 μm or more and 1.8 μm or less. When the surface roughness Ra is 0.7 μm or more, gloss can be further reduced, making it easier to achieve a luxurious feel. On the other hand, when the surface roughness Ra is 2.1 μm or less, the gloss of the layer of the thermoplastic polyurethane resin composition is not excessively reduced, so the luxurious feel can be better maintained. The surface roughness Ra can be measured using a contact surface roughness / shape measuring instrument.

[0070] The thickness of the thermoplastic polyurethane resin composition layer is not particularly limited, but is preferably, for example, 30 μm or more and 300 μm or less. When the thickness of the thermoplastic polyurethane resin composition layer is 30 μm or more, not only can the reinforcing fiber layer be more adequately protected, but also fiber fluffing can be further suppressed. When the thickness of the thermoplastic polyurethane resin composition layer is 300 μm or less, the three-dimensional shape of the three-dimensional structure can be better maintained. From the same viewpoint, the thickness of the thermoplastic polyurethane resin composition layer is more preferably 100 μm or more and 200 μm or less.

[0071] 1-6.Applications The decorated three-dimensional structure 10 can be used for various purposes. For example, the decorated three-dimensional structure 10 can be used for automobile interior and exterior components (e.g., automobile seats, armrests, door trim, instrument panels, console boxes, steering covers, ceiling materials, and other interior components, and doors, dashboards, back doors, spoilers, and other exterior components), furniture (e.g., door handles, lamp shades), sporting goods (e.g., various grips), daily necessities (e.g., business card holders, accessory cases, eyeglass cases, eyeglass frames, various pen grips), and housings for electrical appliances (e.g., notebook PC housings, housings, audio speakers, smartphone covers).

[0072] 2. Manufacturing method for decorated three-dimensional structures 2A to 2E and 3A and 3B are schematic cross-sectional views showing a method for manufacturing a decorated three-dimensional structure 10 according to one embodiment of the present invention.

[0073] The decorated three-dimensional structure 10 can be produced, for example, through the following steps: 1) a first step (see Figures 2A to 2E) of bonding a three-dimensional structure 11 and a fiber aggregate 13A containing carbon fiber together via a first adhesive 12A; and 2) a second step (see Figures 3A and 3B) of heating the fiber aggregate 13A bonded to the three-dimensional structure 11 and a sheet 15A of a thermoplastic polyurethane resin composition together via a second adhesive 14A under reduced pressure.

[0074] 2-1. 1st process First, the three-dimensional structure 11 and the fiber assembly 13A are bonded together via the first adhesive 12A (see FIGS. 2A to 2E). Both the three-dimensional structure 11 and the fiber assembly 13A are as described above.

[0075] In this embodiment, after applying a first adhesive 12A onto a three-dimensional structure 11 (see FIGS. 2A and 2B), a fiber aggregate 13 is laminated on the first adhesive 12A and bonded together (see FIGS. 2C and 2D). Note that the bonding procedure is not limited to this, and the three-dimensional structure 11 and the fiber aggregate 13A may be laminated and bonded together at the same time via the first adhesive 12A.

[0076] The first adhesive 12A is an adhesive that constitutes the first adhesive layer 12. The first adhesive 12A may be in a liquid form or a sheet form. In the present embodiment, the first adhesive 12A may be a sheet-like adhesive (double-sided adhesive sheet) (see FIG. 2B).

[0077] The bonding can be performed by, for example, press molding or vacuum molding. Among these, press molding is preferred from the viewpoint of preventing wrinkles from occurring in the fiber aggregate 13A during bonding. Press molding can be performed by press-molding the fiber aggregate 13A onto the first adhesive 12A on the three-dimensional structure 11 using a female mold 20 (see FIGS. 2C and 2D). The bonding can be performed at room temperature (e.g., 23°C) or under heating.

[0078] As a result, a laminate L1 including the three-dimensional structure 11, the first pressure-sensitive adhesive 12A, and the fiber assembly 13A is obtained (see FIG. 2E).

[0079] 2-2.Second process Next, the fiber aggregate 13A (fiber aggregate 13A of laminate L1) attached to the three-dimensional structure 11 and the sheet 15A of the thermoplastic polyurethane resin composition described above are heated under reduced pressure and attached together via the second adhesive 14A (see Figures 3A and 3B).

[0080] The second adhesive 14A can be the same as the first adhesive 12A described above. The second adhesive 14A may be the same as or different from the first adhesive 12A.

[0081] The second adhesive 14A may be applied in advance to either the fiber aggregate 13A or the thermoplastic polyurethane resin composition sheet 15A. In this embodiment, the second adhesive 14A is applied in advance to the sheet 15A. That is, after a laminate L2 is obtained from the thermoplastic polyurethane resin composition sheet 15A and the second adhesive 14A (see FIG. 3A), the second adhesive 14A of the laminate L2 is attached to the fiber aggregate 13A of the laminate L1 (see FIG. 3B). This allows the sheet 15A to stretch more easily during attachment because the second adhesive 14A has a relatively high flexibility, thereby further preventing wrinkles from forming in the sheet 15A and air bubbles from remaining between the fiber aggregate 13A and the sheet 15A.

[0082] At least one surface of the thermoplastic polyurethane resin composition sheet 15A may be textured. This can further enhance the design of the resulting three-dimensional structure. The texture can be imparted, for example, by laminating a texture transfer film, thermocompressing it, and then peeling it off.

[0083] The lamination can be performed by various molding methods, such as insert molding, vacuum molding, pressure molding, TOM (Three Dimension Overlay Method), etc. Among these, the TOM method is preferred from the viewpoint that it is easy to successfully laminate the laminate even to a three-dimensional structure having a complex three-dimensional shape.

[0084] The heating temperature during lamination is 115°C or higher, and preferably 120°C or higher. When the heating temperature is 115°C or higher, the laminate L2 becomes more flexible due to heat, so it can easily conform to the three-dimensional shape of the three-dimensional structure 11 and is less likely to wrinkle. This makes it more difficult for the thermoplastic polyurethane resin composition sheet 15A to wrinkle during lamination. On the other hand, the upper limit of the heating temperature is not particularly limited, but is preferably 135°C or lower from the viewpoint of making it easier to maintain the sheet shape and preventing the sheet from excessively stretching during lamination and therefore less likely to wrinkle, or, in the case of a textured sheet 15A, from the viewpoint of further suppressing the disappearance of the texture due to melting.

[0085] This allows for the production of a decorated three-dimensional structure 10 comprising a three-dimensional structure 11, a first adhesive layer 12, a reinforcing fiber layer 13 containing a fiber aggregate, a second adhesive layer 14, and a layer 15 of a thermoplastic polyurethane resin composition (see Figure 3B). [Example]

[0086] The present invention will be further described below with reference to examples and comparative examples, but the technical scope of the present invention is not limited thereto.

[0087] 1. Preparation of Thermoplastic Polyurethane Films 1-1.Materials Polyisocyanate (A) 1,4-H6XDI: 1,4-bis(isocyanatomethyl)cyclohexane obtained in accordance with the description of Production Example 3 in International Publication WO2019 / 069802 The purity of 1,4-H6XDI was measured by gas chromatography. The purity was 99.9%. The hue was measured by APHA measurement. The hue was 5. 13 The ratio of trans isomers to cis isomers was measured by C-NMR, and it was found that the trans isomer accounted for 86 mol % and the cis isomer accounted for 14 mol %. Macropolyol (B) PTG-1000: Crystalline polytetramethylene ether glycol, trade name PTG1000 (number average molecular weight 1000, average number of hydroxyl groups 2, manufactured by Korea PTG) UP-100: Amorphous polycarbonate diol (Ube Industries, Ltd., UP-100, number average molecular weight (Mn) 10,000, average number of hydroxyl groups 2) Low molecular weight polyol (C) 1,4-BD: 1,4-butanediol (Mitsubishi Chemical Corporation) Additives Irganox 245 (BASF Japan, hindered phenol compound, antioxidant) Tinuvin 571 (manufactured by BASF Japan, benzotriazole compound, UV absorber) ADK STAB LA-72 (ADEKA Corporation, hindered amine compound, weathering stabilizer)

[0088] 1-2. Preparation of thermoplastic polyurethane resin The macropolyol (B) shown in Table 1 was mixed with the above additives. Note that, relative to 100 parts by mass of the macropolyol (B), 0.3 parts by mass of Irganox 245 (antioxidant), 0.3 parts by mass of Tinuvin 571 (ultraviolet absorber), and 0.3 parts by mass of Adekastab LA-72 (weather stabilizer) were used, and the total amount of additives was 0.9% by mass relative to the final mass of the thermoplastic polyurethane resin. Next, the mixture of macropolyol (B) and additives was placed in a container filled with nitrogen and heated at 100° C. for 12 hours. Meanwhile, a catalyst solution was prepared by diluting dibutyltin dilaurate (catalyst) with DINA (diisononyl adipate, catalyst diluent) to 4 mass %. A container equipped with a stirrer, a thermometer, and a nitrogen inlet tube was charged with 173 parts by mass of polyisocyanate (A), 100 parts by mass of macropolyol (B), and the above-mentioned mixture of additives. These were stirred with a high-speed stirring disper in a nitrogen atmosphere in a water bath at 85°C for 5 minutes to obtain an isocyanate-terminated prepolymer. Next, 73 parts by mass of low-molecular-weight polyol (C) as a chain extender was added to the isocyanate-terminated prepolymer, and the mixture was stirred with a high-speed stirring disper while appropriately adding a catalyst solution until the temperature reached 90°C. Next, the mixture of the isocyanate group-terminated prepolymer and the chain extender was poured into a Teflon (registered trademark) tray and subjected to a urethane reaction at 150°C for 2 hours, and the reaction was continued at 100°C for 20 hours, thereby obtaining a thermoplastic polyurethane resin.

[0089] The thermoplastic polyurethane resin was then removed from the vat, cut into cubes using a bale cutter, and crushed into crushed pellets. The crushed pellets were then heat-treated at 80°C for 5 days and then dried at 80°C under reduced pressure in vacuum for 12 hours. The crushed pellets were then placed in a single-screw extruder (model: SZW20-25MG, manufactured by Technobel Co., Ltd.), and strands were extruded at a cylinder temperature of 140°C or higher and 240°C or lower. Thereafter, the strand was cut to obtain pellets of thermoplastic polyurethane resins 1 and 2, respectively.

[0090] The compositions and physical properties of the resulting thermoplastic polyurethane resins 1 and 2 are shown in Table 1. [Table 1]

[0091] 1-3. Preparation of thermoplastic polyurethane resin film (Preparation of TPU film 1) The obtained pellets of thermoplastic polyurethane resin 1 were dried under reduced pressure in vacuum at 80°C for 12 hours. Next, the pellets of thermoplastic polyurethane resin 1 were charged into a single-screw extruder, and the thermoplastic polyurethane resin was extruded through a T-die at a screw rotation speed of 20 rpm and a cylinder temperature of 140 to 240°C, and taken up by a take-up machine, thereby obtaining a TPU film 1 with a thickness of 150 μm. Thereafter, the obtained TPU film 1 (polycarbonate-based TPU film) was aged for 7 days under constant temperature and humidity conditions of room temperature 23°C and relative humidity 55%.

[0092] (Preparation of TPU film 2) A TPU film 2 having a thickness of 150 μm was obtained in the same manner except that the thermoplastic polyurethane resin 1 was changed to the thermoplastic polyurethane resin 2. Thereafter, the obtained TPU film 2 (polytetramethylene ether glycol-based TPU film) was aged for 7 days under constant temperature and humidity conditions of room temperature 23°C and relative humidity 55%.

[0093] 2. Fabrication and evaluation of decorated three-dimensional structures 2-1.Materials (Three-dimensional structure (core material)) Acrylonitrile butadiene styrene resin structure (ABS molded part, height 3cm x width 13cm x depth 15cm)

[0094] (fiber aggregate containing carbon fiber) Fiber assembly 1: Twill weave (thickness 300 μm) of warp (carbon fiber) and weft (aramid fiber) Fiber assembly 2: Plain weave (thickness 300 μm) of warp (carbon fiber) and weft (aramid fiber) Fiber assembly 3: Plain weave (thickness 300 μm) of warp (carbon fiber) and weft (carbon fiber) The carbon fiber used was EC3C (manufactured by Formosa).

[0095] (adhesive) Acrylic adhesive sheet: MoldFit50 (manufactured by Nichiei Shinka Co., Ltd., acrylic double-sided adhesive sheet, thickness 50 μm)

[0096] (transparent resin sheet) TPU film 1: Polycarbonate-based TPU film (thickness 150 μm) prepared as above TPU film 2: Polytetramethylene ether glycol-based TPU film (thickness 150 μm) prepared as above PP film: Polypropylene film (thickness 150 μm)

[0097] 2-2. Fabrication and evaluation of decorated three-dimensional structures [Example 1] First, an acrylic adhesive sheet (adhesive) was attached to the surface of the ABS molded product, which was a three-dimensional structure. Next, the fiber assembly 1 was pressed at room temperature using a female mold to obtain a laminate (laminate L1) including the three-dimensional structure, the adhesive layer, and the fiber assembly 1.

[0098] On the other hand, a texture transfer film (a PP film with a surface roughness Ra of 0.7 to 2.1 μm) was thermocompression bonded to the surface of the TPU film prepared above, and then peeled off to create a texture. The thermocompression bonding was performed at 150°C and 1 MPa for 3 minutes. An acrylic adhesive sheet (adhesive) was laminated on the surface of this TPU film 1 on which the texture was not transferred, to prepare a laminate (laminate L2).

[0099] Then, laminate L1 and laminate L2 were bonded together using the TOM molding method under reduced pressure at 125°C so that the fiber aggregate 1 of laminate L1 and the acrylic adhesive sheet of laminate 2 were in contact, thereby obtaining a decorated three-dimensional structure.

[0100] [Example 2] A decorated three-dimensional structure was obtained in the same manner as in Example 1, except that the type of fiber assembly was changed as shown in Table 1.

[0101] [Example 3] A decorated three-dimensional structure was obtained in the same manner as in Example 1, except that the type of fiber assembly, the type of transparent resin sheet, and the molding conditions (laminate 2) were changed as shown in Table 1.

[0102] [Example 4] A decorated three-dimensional structure was obtained in the same manner as in Example 3, except that the molding temperature was changed to 140°C.

[0103] [Comparative Example 1] A decorated three-dimensional structure was obtained in the same manner as in Example 3, except that the TPU film was changed to a PP film and the temperature during lamination of the PP film was changed as shown in Table 1.

[0104] Comparative Example 2 A decorated three-dimensional structure was obtained in the same manner as in Example 3, except that the type of TPU film was changed as shown in Table 1 and no adhesive sheet was used to bond the TPU film.

[0105] Comparative Example 3 A decorated three-dimensional structure was obtained in the same manner as in Example 1, except that no adhesive sheet was used to bond the TPU film and the bonding method and temperature of the TPU film were changed as shown in Table 1.

[0106] [evaluation] The appearance and shape retention of the decorated three-dimensional structure were evaluated by the following methods.

[0107] (Appearance rating 1: wrinkles) The appearance of the obtained three-dimensional structure was visually observed, and was rated as A when there were no wrinkles in either the carbon fiber aggregate or the transparent resin sheet, and B when there were wrinkles in either the carbon fiber aggregate or the transparent resin sheet.

[0108] (Appearance rating 2: bubbles) The appearance of the obtained three-dimensional structure was visually observed. When no air bubbles were present between the fiber aggregate and the transparent resin sheet, it was rated as A, and when air bubbles were present between the fiber aggregate and the transparent resin sheet, it was rated as B. When air bubbles were present, the appearance was observed to be whitened and the adhesion between the fiber aggregate and the transparent resin sheet was also reduced.

[0109] (Appearance rating 3: gloss) The appearance of the obtained three-dimensional structure was visually observed, and was rated as A when no gloss (luster) was observed, and B when gloss was observed.

[0110] (shape retention) The area of ​​the resulting three-dimensional structure is 1 cm 2 When pressed with 1 kgf (0.1 MPa), the deformation was rated as A if it was 5 mm or less, and B if it was 5 mm or more.

[0111] The evaluation results of Examples 1 to 4 are shown in Table 2, and the evaluation results of Comparative Examples 1 to 3 are shown in Table 3. Note that if both appearance evaluations 1 and 2 were A, it was considered to be within the acceptable range.

[0112] [Table 2]

[0113] As shown in Table 2, the three-dimensional structures of Comparative Examples 2 and 3, in which a fiber assembly and a TPU film were bonded together without an adhesive sheet, exhibited wrinkles and bubbles. In Comparative Examples 2 and 3, the heating temperature during heating of the TPU film before molding was too high, causing the film to stretch before being pressed against the mold. It is believed that the wrinkles and bubbles were generated because the TPU film was pressed against the fiber assembly in this stretched state. Furthermore, the three-dimensional structure of Comparative Example 1, in which a PP film was used instead of a TPU film, also exhibited wrinkles and bubbles. This is believed to be because the PP film is difficult to stretch at a molding temperature of 150°C.

[0114] In contrast, the three-dimensional structures of Examples 1 to 4, in which a fiber aggregate (not impregnated with resin) was bonded via an adhesive sheet and a TPU film was bonded via an adhesive sheet, were all found to have almost no wrinkles or bubbles and to have a good appearance.

[0115] From these findings, it can be seen that by bonding a fiber assembly via an adhesive sheet and then bonding a TPU film via an adhesive sheet, a three-dimensional structure with almost no wrinkles or bubbles and a good appearance can be obtained. [Industrial Applicability]

[0116] According to the present invention, it is possible to provide a three-dimensional structure that is decorated with a fiber aggregate containing carbon fiber and has excellent aesthetic appeal. [Explanation of symbols]

[0117] 10 Decorated three-dimensional structures 11 Three-dimensional structures 12 1st adhesive layer 12A First adhesive 13 Reinforced fiber layer 13A Fiber assembly 14 Second adhesive layer 14A Second adhesive 15 Thermoplastic polyurethane resin composition layer 15A Thermoplastic polyurethane resin composition sheet L1, L2 laminate

Claims

1. A decorated three-dimensional structure, A three-dimensional structure, a first adhesive layer laminated on the surface of the three-dimensional structure; a reinforced fiber layer laminated on the first adhesive layer, including carbon fibers and having voids; A second adhesive layer laminated on the reinforcing fiber layer; a layer of a thermoplastic polyurethane resin composition laminated on the second adhesive layer; Including, Decorated three-dimensional structure.

2. A method for manufacturing a decorated three-dimensional structure, comprising: a first step of bonding a three-dimensional structure and a fiber aggregate containing carbon fibers via a first pressure-sensitive adhesive; a second step of bonding the fiber aggregate bonded to the three-dimensional structure and a sheet of a thermoplastic polyurethane resin composition via a second pressure-sensitive adhesive at a temperature of 115°C or higher under reduced pressure; Including, A method for manufacturing a decorated three-dimensional structure.

3. In the second step, preparing a laminate of a sheet of a thermoplastic polyurethane resin composition and the second pressure-sensitive adhesive; The second pressure-sensitive adhesive of the laminate is attached to the fiber aggregate. A method for manufacturing the decorated three-dimensional structure according to claim 2.

4. In the second step, The lamination is performed at a temperature of 120°C or higher and 135°C or lower. A method for manufacturing the decorated three-dimensional structure according to claim 2 or 3.

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