Layer, automobile interior member, and method for producing automobile interior member

Abstract

The present invention provides: a layer which is formed using a hot melt adhesive and has excellent performance; an automobile interior member which comprises this layer; and a method for producing an automobile interior member.　One embodiment of the present invention provides a layer which is formed of an aggregate of fibrous hot melt adhesives, and which is characterized in that the aggregate of the hot melt adhesives contains an acid-modified polypropylene resin.

Description

layer, automobile interior member, and method for manufacturing automobile interior member - Patents.com

[0001] The present invention relates to a layer, an automotive interior component, and a method for making an automotive interior component.

[0002] Hot melt adhesives are used in a variety of fields because they are easy to work with and can fix objects to be adhered simply by cooling and solidifying after application of pressure.

[0003] In the production of laminates used for automobile interiors, for example, the olefin hot melt adhesive disclosed in Patent Document 1 can be used.

[0004] International Publication No. 2015 / 111488

[0005] However, the layers obtained using hot melt adhesives according to the prior art do not meet sufficient performance requirements.

[0006] Therefore, an object of the present invention is to provide a layer having excellent performance formed using a hot melt adhesive, an automobile interior member including such a layer, and a method for manufacturing the automobile interior member.

[0007] One aspect of the present invention is a layer formed by an assembly of fibrous hot melt adhesives, wherein the assembly of hot melt adhesives contains an acid-modified polypropylene resin.

[0008] Another aspect of the present invention is an automobile interior component comprising the layer of the above aspect.

[0009] Yet another aspect of the present invention is a method for producing an automotive interior component, the method comprising the step of spray-coating a hot melt adhesive directly onto a substrate to form a resin fiber adhesive layer, wherein the hot melt adhesive is an olefin-based hot melt adhesive containing a polyolefin and an acid-modified polypropylene resin.

[0010] Yet another aspect of the present invention is a method for producing an automotive interior component, the method comprising the step of spray-coating an olefin-based hot melt adhesive directly onto a substrate using an automatically controlled coating device to form a resin fiber adhesive layer.

[0011] According to the present invention, it is possible to provide a layer having excellent performance formed using a hot melt adhesive, an automobile interior member including the layer, and a method for manufacturing the automobile interior member.

[0012] FIG. 1 shows a conceptual diagram and a block diagram of an example of an automatically controlled coating device.

[0013] In this specification, when multiple upper limit values ​​and multiple lower limit values ​​are separately described, all numerical ranges that can be set by freely combining these upper limit values ​​and lower limit values ​​are considered to be described in this specification.

[0014] In the following, when a compound is described, its isomers are also described.

[0015] In the present invention, the number average molecular weight or weight average molecular weight is measured by gel permeation chromatography.

[0016] In the present invention, the softening point is measured in accordance with JIS K 6863:1994 "Testing method for softening point of hot melt adhesives." Furthermore, in the present invention, the melting point refers to the melting peak temperature obtained by DSC.

[0017] The technology according to the present disclosure relates to a layer formed by an aggregate of fibrous hot melt adhesive. Expressed another way, the technology according to the present disclosure relates to a resin fiber layer formed by a fibrous hot melt adhesive. Expressed still another way, the technology according to the present disclosure relates to a laminate having a substrate and a resin fiber layer formed by a fibrous hot melt adhesive.

[0018] Hereinafter, the layer formed by an aggregate of fibrous hot melt adhesive may be simply referred to as a resin fiber adhesive layer.

[0019] Below, we will explain the hot melt adhesive that constitutes the resin fiber adhesive layer, the structure of the resin fiber adhesive layer, the uses or application locations of the resin fiber adhesive layer, and the manufacturing method of the resin fiber adhesive layer.

[0020] <<<<Hot Melt Adhesive>>>> <<<Components of Hot Melt Adhesive>>>> The hot melt adhesive preferably contains acid-modified polypropylene. In other words, the resin fiber adhesive layer preferably contains acid-modified polypropylene.

[0021] The hot melt adhesive preferably contains a polyolefin. In other words, the resin fiber adhesive layer preferably contains a polyolefin. Hereinafter, a hot melt adhesive containing a polyolefin may be referred to as an olefin-based hot melt adhesive. In other words, one preferred form of the hot melt adhesive according to the present disclosure is an olefin-based hot melt adhesive.

[0022] The hot melt adhesive may contain other ingredients.

[0023] Each component will be described below.

[0024] <<Acid-Modified Polypropylene>> Acid-modified polypropylene is, for example, polypropylene graft-polymerized with an unsaturated carboxylic acid or a derivative thereof.

[0025] By using acid-modified polypropylene, it is possible to obtain a hot melt adhesive having sufficient open time and excellent peel strength at high temperatures, etc. Furthermore, in particular, by using the above-mentioned polyolefin in combination with acid-modified polypropylene, these effects can be further enhanced.

[0026] Examples of unsaturated carboxylic acids include maleic acid, fumaric acid, itaconic acid, acrylic acid, etc. Examples of derivatives of unsaturated carboxylic acids include maleic anhydride, itaconic anhydride, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, and monoethyl maleate.

[0027] From the viewpoint of improving high-temperature peel strength and wettability during application, the acid-modified polypropylene is preferably maleic acid-modified polypropylene or maleic anhydride-modified polypropylene, and maleic acid-modified polypropylene is particularly preferred.

[0028] The acid-modified polypropylene preferably has an acid value of 1 to 100 mgKOH / g or an acid content of 0.5 to 10 wt %. The acid value can be measured in accordance with JIS K 0070.

[0029] The melting point of the acid-modified polypropylene can be, for example, 60 to 180°C, or 70 to 170°C.

[0030] The weight average molecular weight of the acid-modified polypropylene can be, for example, 5,000 to 200,000, or 7,500 to 100,000.

[0031] Content of acid-modified polypropylene in hot melt adhesive M Ｂ is preferably 0.1% by mass or more, 1% by mass or more, 2% by mass or more, or 3% by mass or more, and is preferably 20% by mass or less, 15% by mass or less, or 12% by mass or less.

[0032] The acid-modified polypropylene is not limited to the above-mentioned polypropylene graft-polymerized with an unsaturated carboxylic acid or its derivative, but may be any conventionally known polypropylene. For example, the acid-modified polypropylene may be polypropylene whose terminal portions are acid-modified. Examples of polypropylene whose terminal portions are acid-modified include polypropylene containing double bonds at both ends (e.g., obtained by thermally decomposing polypropylene) in which the terminal double bonds are acid-modified with an unsaturated carboxylic acid or its derivative. In this way, acid-modified polypropylene whose terminal portions are acid-modified is capable of suppressing the reduction in molecular weight during acid modification (easier to maintain an appropriate molecular weight range), thereby suppressing the reduction in strength and improving the adhesiveness when bonding different materials.

[0033] <<Polyolefin>> The polyolefin is not particularly limited, and conventionally known polyolefins can be used. Examples of polyolefins include polyethylene, polypropylene, polybutene-1, polypropylene copolymers (e.g., ethylene-propylene copolymers), ethylene-α-olefin copolymers, and polymer blends thereof.

[0034] The polyolefin is preferably a mixture of a polyolefin having a relatively high softening point and a polyolefin having a relatively low softening point. More specifically, the polyolefin preferably contains a polyolefin (A1) having a softening point of 130°C or higher and a polyolefin (A2) having a softening point of less than 130°C.

[0035] The softening point of the polyolefin (A1) may be 135°C or higher, 140°C or higher, 145°C or higher, 150°C or higher, or 155°C or higher. The softening point of the polyolefin (A1) may also be less than 180°C, less than 175°C, less than 170°C, or less than 165°C.

[0036] The softening point of the polyolefin (A2) may be less than 128° C., less than 125° C., less than 123° C., or less than 120° C. Alternatively, the softening point of the polyolefin (A2) may be 100° C. or higher, 105° C. or higher, 110° C. or higher, or 115° C. or higher.

[0037] The difference between the softening point of the polyolefin (A1) and the softening point of the polyolefin (A2) may be more than 0°C, but is preferably 5°C or more, 10°C or more, 15°C or more, 20°C or more, 25°C or more, or 30°C or more, and is preferably 55°C or less, 50°C or less, or 45°C or less.

[0038] By setting the softening point of the polyolefin (A1) and the softening point of the polyolefin (A2) within these ranges, it is possible to obtain a hot melt adhesive that is excellent in viscosity characteristics and high-temperature peel strength.

[0039] The softening point of the polyolefin can be adjusted by changing the molecular weight, the type and composition ratio of the monomers used, and the like.

[0040] The total content of polyolefins in the hot melt adhesive (the total content of polyolefin (A1) and polyolefin (A2)) can be, for example, 50% by mass or more, 55% by mass or more, 60% by mass or more, or 65% by mass or more, and can be 90% by mass or less, 85% by mass or less, 80% by mass or less, or 75% by mass or less.

[0041] The content M of polyolefin (A1) in the hot melt adhesive Ａ１ is preferably 0.1% by mass or more, 1% by mass or more, 5% by mass or more, 8% by mass or more, or 10% by mass or more, and is preferably 30% by mass or less, 25% by mass or less, or 20% by mass or less.

[0042] The content M of polyolefin (A2) in the hot melt adhesive Ａ２ is preferably 0.1% by mass or more, 1% by mass or more, 10% by mass or more, 30% by mass or more, 40% by mass or more, or 50% by mass or more, and is preferably 80% by mass or less, 70% by mass or less, or 60% by mass or less.

[0043] The content M of polyolefin (A2) in the hot melt adhesive Ａ２ and the content M of polyolefin (A1) Ａ１ The ratio [M Ａ２ / M Ａ１ ] is preferably greater than 1.0, 1.5 or greater, 2.0 or greater, 2.5 or greater, or 3.0 or greater, and is preferably 8.0 or less, 7.0 or less, 6.0 or less, 5.5 or less, 5.0 or less, 4.5 or less, or 4.0 or less.

[0044] By setting the content of polyolefin (A1) or polyolefin (A2) within such range, it is possible to obtain a hot melt adhesive that is excellent in viscosity characteristics and high-temperature peel strength.

[0045] In addition, among hot melt adhesives, M Ａ２ / (M Ａ１ +M Ｂ ) is preferably greater than 1, 1.5 or greater, or 2 or greater, and is preferably 5 or less, 4 or less, or 3 or less. By setting it within such a range, it is possible to improve the viscosity characteristics, high-temperature peel strength, and the like in a balanced manner while maintaining an appropriate open time.

[0046] The polyolefin (A1) and the polyolefin (A2) may be made of the same or different monomers. The polyolefin (A2) preferably contains polybutene-1.

[0047] From the viewpoint of viscosity characteristics and the like, the polyolefin is preferably a poly-α-olefin, and more preferably an amorphous poly-α-olefin.

[0048] Poly-α-olefin refers to a polymer obtained by polymerizing α-olefin, and amorphous poly-α-olefin refers to a poly-α-olefin that does not have a clear melting point.

[0049] The amorphous poly-α-olefin may be a known one, such as those described in Japanese Patent No. 6001685 or Japanese Patent No. 3153648. The amorphous poly-α-olefin may be, for example, an amorphous olefin resin obtained by polymerizing (or copolymerizing) propylene, ethylene, and 1-butene alone or in combination.

[0050] Only one of the polyolefin (A1) and the polyolefin (A2) may be a poly-α-olefin or an amorphous poly-α-olefin, but it is preferable that both the polyolefin (A1) and the polyolefin (A2) are poly-α-olefins or amorphous poly-α-olefins.

[0051] The weight average molecular weight of the polyolefin (or polyolefin (A1) and polyolefin (A2)) is not particularly limited as long as it does not impair the effects of the present disclosure, but is preferably, for example, 10,000 to 200,000, 15,000 to 150,000, or 20,000 to 100,000. By setting the weight average molecular weight of the polyolefin within such a range, a hot melt adhesive with excellent viscosity characteristics and the like can be obtained.

[0052] The tensile strength of the polyolefin (or polyolefin (A1) and polyolefin (A2)) is preferably 1.0 MPa or more, 2.0 MPa or more, or 3.0 MPa or more. The upper limit of the tensile strength is, for example, 50 MPa, 40 MPa, 30 MPa, or 20 MPa. The tensile strength is, for example, a value measured in accordance with ASTM D638 at a test speed of 5 mm / min.

[0053] <<Other Components>> Examples of other components include various additives such as tackifiers, antioxidants, antiaging agents, fillers, plasticizers, pigments, dyes, antistatic agents, flame retardants, antibacterial agents, light stabilizers, stabilizers, dispersants, fluorescent brighteners, and solvents.

[0054] When a tackifier is included as another component, the tackifier may be a natural resin, but is preferably a synthetic resin such as a petroleum resin (hydrocarbon resin), a hydrogenated (hydrogenated) petroleum resin (hydrocarbon resin), a styrene resin, a coumarone-indene resin, a phenolic resin, or a xylene resin. Furthermore, the tackifier is preferably a (hydrogenated) petroleum resin such as a (hydrogenated) aliphatic (C5) petroleum resin, a (hydrogenated) aromatic (C9) petroleum resin, a (hydrogenated) copolymer (C5 / C9) petroleum resin, a (hydrogenated) dicyclopentadiene petroleum resin, or an alicyclic saturated hydrocarbon resin, with a (hydrogenated) aliphatic (C5) petroleum resin being particularly preferred.

[0055] The content of the tackifier in the hot melt adhesive can be 5 to 40 mass %, 10 to 35 mass %, or 15 to 30 mass %.

[0056] The hot melt adhesive can be produced by a known method, for example, by feeding the above-mentioned raw materials into a continuous mixer such as a single-screw or twin-screw extruder, or a batch mixer such as a roll mixer, a Banbury mixer, a kneader, a planetary mixer, or a high-shear Z-blade mixer, and mixing them for a predetermined period of time.

[0057] The hot melt adhesive according to the present disclosure can be used in a variety of conventionally known ways, and is particularly suitable for spray application because it is likely to have excellent viscosity characteristics, high-temperature peel strength, sufficient open time, etc. In this specification, "spray application" refers to spraying a molten hot melt adhesive into fibers using air pressure. Equipment that can be used for spray application will be described later.

[0058] <<<Physical Properties of Hot Melt Adhesive>>> The melt viscosity of the hot melt adhesive at 200°C is preferably 50,000 mPa·s or less, 30,000 mPa·s or less, 20,000 mPa·s or less, 10,000 mPa·s or less, 8,000 mPa·s or less, 6,000 mPa·s or less, 5,000 mPa·s or less, or 4,000 mPa·s or less.

[0059] The melt viscosity of the hot melt adhesive at 180°C is preferably 100,000 mPa·s or less, 50,000 mPa·s or less, 30,000 mPa·s or less, 20,000 mPa·s or less, 15,000 mPa·s or less, 10,000 mPa·s or less, 8,000 mPa·s or less, or 6,000 mPa·s or less.

[0060] The melt viscosity of the hot melt adhesive at 160°C is preferably 150,000 mPa·s or less, 100,000 mPa·s or less, 60,000 mPa·s or less, 40,000 mPa·s or less, 30,000 mPa·s or less, 15,000 mPa·s or less, 12,000 mPa·s or less, or 11,000 mPa·s or less.

[0061] The melt viscosity is measured by heating the hot melt adhesive to a predetermined temperature using a parallel plate rheometer at an oscillation angle of 10% and an angular frequency of 1 rad / s.

[0062] The crystallization temperature of the hot melt adhesive is preferably 40 to 140° C., 50 to 130° C., or 60 to 125° C. By setting the temperature within such a range, it is possible to improve the viscosity characteristics, high-temperature peel strength, etc. in a balanced manner while maintaining an appropriate open time.

[0063] The crystallization temperature is measured in accordance with JIS-K7121.

[0064] <<<<<Structure of Resin Fiber Adhesive Layer>>>> <<<Effective Area>>> The effective area of ​​the resin fiber adhesive layer is preferably 40% or more, 50% or more, or 60% or more. The effective area of ​​the resin fiber adhesive layer was measured as the area (%) of the hot melt adhesive application portion using an automatic area measurement attached to a microscope (VHX-7000, manufactured by Keyence Corporation). The effective area was measured by applying 50 g / m2 of hot melt adhesive to a black paper so as to have the same structure (fiber system and fiber density) as the target resin fiber adhesive layer. ２ The hot melt adhesive is applied using a nozzle, and the area (%) of the resulting resin fiber adhesive layer coated with the hot melt adhesive is measured using an automatic area measurement attached to a microscope.

[0065] The effective area can be adjusted by changing the nozzle (nozzle diameter, distance between nozzle holes, etc.) used when spraying.

[0066] <<<<<Uses or Application Locations of Resin Fiber Adhesive Layer>>>> The resin fiber adhesive layer according to this embodiment is particularly suitable as an adhesive layer for polyolefin members such as polyethylene, polypropylene, and ethylene-propylene copolymer (an adhesive layer used to bond polyolefin members to each other, or to bond a polyolefin member to a member made of a material other than polyolefin). When bonding a polyolefin member to a member made of a material other than polyolefin, the material other than polyolefin may be any of natural materials, artificial materials, and composite materials thereof, and a wide range of materials such as genuine leather, artificial leather, and fabric materials can be used. The polyolefin member is preferably polypropylene.

[0067] The resin fiber adhesive layer according to the present disclosure can be suitably used for interior components (for fastening interior components) in vehicles such as airplanes, ships, and cars (automobiles, railway cars), and is particularly suitable for use in vehicle interior components. More specifically, the resin fiber adhesive layer according to the present disclosure can be used to fasten the skin of automobile interior components (instrument panels, pillars, door trims, etc.). In other words, the resin fiber adhesive layer according to the present disclosure is preferably used as a layer provided in automobile interior components (for example, an adhesive layer that bonds a substrate and a skin).

[0068] A member (for example, a vehicle interior member) provided with the resin fiber adhesive layer according to this embodiment tends to exhibit stable and excellent peel strength (particularly excellent high-temperature peel strength).

[0069] Here, an example of a vehicle interior component may include a vehicle interior component including a polyolefin resin foam, a polyolefin skin member, and an adhesive layer bonding the polyolefin resin foam and the polyolefin skin member, the adhesive layer being a resin fiber adhesive layer formed of an aggregate of fibrous olefin hot melt adhesive. A laminate having such a structure, in which both the two layers and the adhesive layer interposed between the two layers are all made of polyolefin materials, is likely to exhibit appropriate adhesive strength and be easily recycled, making it particularly suitable as a vehicle interior component. More specifically, by constructing the laminate from a single material, recycling is easier than with laminates made from multiple different materials. While laminates made from multiple different materials that are difficult to recycle are typically discarded (e.g., incinerated), laminates made from a single material can be recycled, which helps reduce emissions of carbon dioxide, a greenhouse gas.

[0070] The polyolefin-based resin foam is a conventionally known resin foam made of a polyolefin-based resin such as polyethylene, polypropylene, or an ethylene-propylene copolymer.

[0071] The polyolefin skin member is a conventionally known sheet-like member made of, for example, a polyolefin resin such as polyethylene, polypropylene, or an ethylene-propylene copolymer, or a thermoplastic elastomer containing a polyolefin resin.

[0072] Examples of the olefin-based hot melt adhesive include hot melt adhesives according to the present disclosure that contain at least polyolefin.

[0073] <<<<<Method for Producing Resin Fiber Adhesive Layer>>>> The resin fiber adhesive layer can be produced by various methods. Hereinafter, a method for producing a resin fiber adhesive layer (or a method for producing a member including a resin fiber adhesive layer) will be described.

[0074] <<<First Form>>> A first form of a method for manufacturing a resin fiber adhesive layer (or a method for manufacturing a member including a resin fiber adhesive layer) is an example of spray application using the above-mentioned hot melt adhesive.

[0075] In this embodiment, first, the hot melt adhesive is maintained in a molten state (melting step). The temperature at which the hot melt adhesive is maintained may be adjusted so that the hot melt adhesive has a desired melt viscosity, taking into consideration the type of hot melt adhesive used, the spray application method, etc.

[0076] Next, the molten hot melt adhesive is sprayed (directly) onto at least one surface of the substrate to be bonded (substrate) in a desired amount (application step). Known spraying methods, such as curtain spraying, omega spraying, spiral spraying, and summit spraying, can be used. Specific application conditions (such as the spraying method and pressure conditions) should be determined so that the resin fiber adhesive layer has the desired structure (fiber diameter and density). The application step may be performed multiple times to adjust the basis weight of the resin fiber adhesive layer.

[0077] The hot melt adhesive discharged from the spray unit reaches the adherend while undulating or being blown out, forming a fiber layer in which the fibers are aligned in a random direction. The spray unit is usually configured with multiple nozzles lined up to increase the coating area in a single coating process. The number of nozzles in the spray unit and the size of the spray unit can be designed as appropriate. Note that it is preferable for the width between the farthest nozzles in the spray unit to be 150 mm or less, as this improves workability.

[0078] In this manner, a resin fiber adhesive layer is formed.

[0079] Here, if it is desired to bond two members via a resin fiber adhesive layer, a laminating step and a solidifying step are further carried out.

[0080] Specifically, after the application step is performed to form a resin fiber adhesive layer on the substrate, the other surface to be adhered is pressed against the resin fiber adhesive layer provided on the substrate (lamination step). In other words, the adherend is laminated on the resin fiber adhesive layer provided on the substrate and pressed against the adherend.

[0081] Next, the hot melt adhesive is cooled and solidified (solidification step).

[0082] In this manner, a laminate in which two members are fixed together via a resin fiber adhesive layer is obtained.

[0083] The curing step is preferably carried out during a period when the resin fiber adhesive layer is not completely cured (for example, within the open time of the hot melt adhesive). The open time of the hot melt adhesive may be extended by, for example, increasing the ambient temperature.

[0084] Prior to the application step, the surface to be bonded may be subjected to a known surface treatment.

[0085] As described above, the hot melt adhesive can be preferably applied by spray coating, and therefore, by forming a resin fiber adhesive layer by spray coating the hot melt adhesive, a laminate having excellent adhesive strength and the like can be easily obtained.

[0086] <<<Second Form>>> A second form of the method for manufacturing a resin fiber adhesive layer (or the method for manufacturing a member including a resin fiber adhesive layer) is an example of the case where an automotive interior member is manufactured using an olefin-based hot melt adhesive, which is a hot melt adhesive including a polyolefin.

[0087] In this embodiment, the method includes a step of spraying the hot melt adhesive directly onto the substrate to form a resin fiber adhesive layer.

[0088] The spray coating method can be the same as that of the coating process described above.

[0089] In this embodiment, the melting step and solidification step described above are also carried out as necessary.

[0090] The substrate and the adherend are not particularly limited. The structures of the substrate and the adherend can be appropriately changed according to the structure of the automobile interior component to which they are applied. The material of the substrate is, for example, a polyolefin (preferably polypropylene). The material of the adherend is, for example, genuine leather, artificial leather, fabric material, etc.

[0091] Here, the olefin-based hot melt adhesive preferably contains acid-modified polypropylene. In other words, the hot melt adhesive preferably contains polyolefin and acid-modified polypropylene. More specifically, the olefin-based hot melt adhesive preferably uses the hot melt adhesive described above.

[0092] Table 1 summarizes a comparison between spray coating using a hot melt adhesive (particularly an olefin-based hot melt adhesive), spray coating using a solvent-based adhesive, and roll coating using a hot melt adhesive (particularly an olefin-based hot melt adhesive).

[0093]

[0094] As shown in Table 1, hot melt adhesives typically do not contain solvents, resulting in a lower loss rate compared to solvent-based adhesives. Furthermore, while hot melt adhesives do not require a drying time, solvent-based adhesives require a predetermined drying time (e.g., 150 seconds). Therefore, the use of hot melt adhesives can shorten the cycle time (the time from application of the adhesive to bonding). Furthermore, while the use of hot melt adhesives offers high safety in that the solvent does not ignite, the use of solvent-based adhesives may require explosion-proof equipment to enhance safety. Furthermore, when forming an adhesive layer by spraying a hot melt adhesive directly onto a substrate, the loss rate is lower than when forming an adhesive layer by laminating an olefin-based hot melt adhesive in a film form. Furthermore, the work process can be simplified because pre-coating or other processes are not required.

[0095] In this way, in the second embodiment, a resin fiber adhesive layer is formed by spraying a hot melt adhesive, and this layer is used as the adhesive layer. Thus, the manufacturing method for an automotive interior member according to the second embodiment is suitable for automating application using an automatically controlled device (a so-called robot) because it is superior in safety compared to methods using general adhesives. Furthermore, the second embodiment is suitable for mass production of automotive interior parts using an automatically controlled device because it does not require a step of drying the solvent in a heating furnace and has a low loss rate.

[0096] In other words, the method for manufacturing an automotive interior member according to the second embodiment is preferably carried out as a manufacturing method including a step of spraying an olefin hot melt adhesive directly onto a substrate using an automatically controlled application device to form a resin fiber adhesive layer.

[0097] In particular, the hot melt adhesives described above can easily adjust the solidification time (extend the solidification time) and achieve high adhesiveness at room temperature, so they can easily achieve stable, high adhesiveness even in bonding processes using automatically controlled application equipment.

[0098] 1 shows a conceptual diagram and a block diagram of an example of an automatically controlled coating apparatus. The automatically controlled coating apparatus will be described below mainly with reference to FIG.

[0099] An example of an automatically controlled application device is one that includes a spray unit (such as the spray head shown in FIG. 1) that can spray hot melt adhesive, and a position adjustment unit (such as the arm shown in FIG. 1) that adjusts the position and orientation of the spray unit.

[0100] Although not shown in Fig. 1, the application device typically includes a spray amount adjusting means (pressure adjusting means or the like) for adjusting the amount of hot melt adhesive sprayed from the spray unit (spray amount). The spray unit may be configured to be detachable / replaceable.

[0101] The application device may also include a hot melt adhesive storage section (e.g., a tank) for storing the hot melt adhesive to be sent to the spray section, a melt state adjustment section (e.g., a temperature adjustment means or a kneading means) for controlling the melt state of the hot melt adhesive in the hot melt adhesive storage section, a flow path section that serves as a flow path for sending the hot melt adhesive from the hot melt adhesive storage section to the spray section, an error detection section that detects the application state using known means such as image recognition, and a communication section for communicating with the outside of the application device.

[0102] The coating device includes a control unit, and each component of the coating device is operated in accordance with an electrical signal sent from the control unit.

[0103] The control unit includes, for example, a storage device that stores information related to the coating process, a position adjustment unit control device that controls the operation of the position adjustment unit based on the information stored in the storage device, and a spray amount adjustment unit control device that controls the operation of the spray amount adjustment unit based on the information stored in the storage device. The storage device stores information related to coating conditions (shape of the substrate, coating area, movement speed of the spray unit, information about the spray unit (e.g., information about the nozzle shape), amount of hot melt adhesive sprayed, number of coating repetitions, environmental information, etc.).

[0104] The control unit may have an information input device, a calculation device, etc. The information input device is, for example, an input terminal for storing information about the above-mentioned coating conditions in a storage device. The calculation device is, for example, a device that can calculate appropriate coating conditions based on the information stored in the storage device.

[0105] At least some of the functions of the control unit may be incorporated in a location (for example, a control room) that is isolated from the coating device via a communication unit or the like.

[0106] The applicator may be controlled to change the amount of hot melt adhesive applied in accordance with the shape of the adherend, etc. For example, when the amount of hot melt adhesive applied per unit time is approximately constant, the applicator may be controlled so that the application speed is increased to reduce the amount applied when the adherend is a smooth surface, and the application speed is decreased to increase the amount applied when the adherend has a complex shape (having an uneven shape or a curved surface).

[0107] In the second embodiment, an automatically controlled device may be included in addition to the coating device. Specifically, examples of automatically controlled devices other than the coating device include devices that automatically move the substrate or the adherend (devices that feed the substrate to the coating position, devices that feed the laminate to the next process after the coating process has been performed, devices that automatically place the adherend in a predetermined position, etc.).

[0108] Furthermore, the method for manufacturing a resin fiber adhesive layer (or the method for manufacturing a component including a resin fiber adhesive layer) using such an automatically controlled application device is applicable not only to the manufacture of automotive interior components, but also to the manufacture of other components.

[0109] The hot melt adhesive composition of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these.

[0110] <<Production of Hot Melt Adhesive Compositions>> Each raw material was prepared as shown in Tables 2 and 3, and each raw material was charged into a mixer and kneaded at 180°C for 20 minutes to obtain a hot melt adhesive composition according to each example.

[0111] <<Analysis / Evaluation>> <Melt Viscosity, Crystallization Temperature> The melt viscosity and crystallization temperature of the hot melt adhesive composition were measured according to the methods described above.

[0112] <<Formation of Resin Fiber Adhesive Layer>> A laminate including a resin fiber adhesive layer was produced as follows. A surface made of fabric or the like and PP resin were used as adherends. The surface made of fabric or the like was used as the coating surface. A coating amount of 55 g / m was applied to a 100 x 25 mm square surface. ２ With this as the target, a molten hot melt adhesive (180°C) is sprayed onto the surface to form a resin fiber adhesive layer.

[0113] <<Analysis / Evaluation>> <Peel Strength> Peel strength was evaluated as follows. The results are shown in Tables 2 and 3. After forming a resin fiber adhesive layer according to the method described above, the PP resin and the surface were bonded together 30 or 60 seconds after application (pressure bonding: 500 g x 10 seconds). The resulting laminate was left for 24 hours in a constant temperature and humidity room at 23°C and 50% humidity. After leaving the laminate, a peel test (ambient temperature: 90°C, tensile speed: 200 mm / min) was performed using an autograph. Each hot melt adhesive had a peel strength of 0.5 N or more after 30 seconds and 60 seconds, which suggests that it has a high-temperature peel strength that is reasonably practical. However, the hot melt adhesives according to each Example, which had a peel strength of more than 1.0 N after 30 seconds and 60 seconds, were considered to have stable and excellent high-temperature peel strength.

[0114] <Effective Area> The effective area was evaluated according to the method described above. The resin fiber adhesive layers of each example all had an effective application area of ​​60% or more.

[0115]

[0116]

[0117] The layer according to the present invention can exhibit excellent adhesive strength when used as an adhesive layer in a laminate, and is therefore preferably used for interior components in vehicles such as automobiles. CROSS-REFERENCE TO RELATED APPLICATIONS

[0118] This application claims priority based on Japanese Patent Application No. 2023-108841, filed with the Japan Patent Office on June 30, 2023, the entire disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A layer formed by an aggregate of fibrous hot-melt adhesives, wherein the hot-melt adhesive comprises acid-modified polypropylene, polyolefin (A1) with a softening point of 130°C or higher, and polyolefin (A2) with a softening point of less than 130°C.

2. A layer formed by an aggregate of fibrous hot-melt adhesives, wherein the hot-melt adhesive comprises an acid-modified polypropylene layer (excluding a hydrophilic plasticizer selected from a condensation ester compound of a fatty acid having 8 to 18 carbon atoms and polyglycerin, a fatty acid ester consisting of a polyoxyethylene chain having a number average molecular weight of 200 to 2000 and a fatty acid having 8 to 20 carbon atoms, and a polypropylene-polyoxyethylene graft polymer).

3. An automotive interior component comprising a layer formed by an aggregate of fibrous hot-melt adhesives, wherein the hot-melt adhesive includes acid-modified polypropylene.

4. The hot melt adhesive comprises a tackifier, The hot melt adhesive contains polyolefin in an amount of 50% by mass or more and 90% by mass or less. The content of the acid-modified polypropylene is 0.1% by mass or more and 20% by mass or less. The automotive interior component according to claim 3, wherein the content of the tackifier is 5% by mass or more and 40% by mass or less.

5. A layer formed by an aggregate of fibrous hot-melt adhesives, wherein the hot-melt adhesives include acid-modified polypropylene, and the acid-modified polypropylene is obtained by graft polymerization of polypropylene with an unsaturated carboxylic acid.

6. The layer according to claim 5, wherein the acid-modified polypropylene is obtained by graft polymerization of polypropylene with an unsaturated carboxylic acid selected from maleic acid, fumaric acid, and itaconic acid.

7. The process includes a coating step of directly spraying an olefin-based hot melt adhesive onto a substrate using an automatically controlled coating device to form a resin fiber adhesive layer, The coating apparatus, A spray unit capable of spraying the aforementioned hot melt adhesive, A position adjustment unit for adjusting the position and orientation of the spray unit, A method for manufacturing automotive interior components, comprising a spray volume adjustment unit for adjusting the amount of hot melt adhesive sprayed from the spray unit.

8. The coating apparatus comprises a control unit, The control unit, A storage device in which information relating to the coating process is stored, A position adjustment unit control device that controls the operation of the position adjustment unit based on the information stored in the storage device, A method for manufacturing an automotive interior member according to claim 7, comprising a spray volume adjustment control device that controls the operation of the spray volume adjustment unit based on the information stored in the storage device.

9. The process includes the step of directly spraying a hot melt adhesive onto a substrate to form a resin fiber adhesive layer, A method for manufacturing automotive interior components, wherein the hot melt adhesive is an olefin-based hot melt adhesive containing polyolefin and acid-modified polypropylene.

10. The automotive interior component is formed by bonding the base material and the adherend with the olefin-based hot melt adhesive, A method for manufacturing an automotive interior member according to any one of claims 7 to 9, wherein the adherend is selected from genuine leather, artificial leather, and fabric material.