JP7699510B2 - Laminated foam sheet, laminated molded product, and manufacturing method thereof - Google Patents

Description

The present invention relates to a laminated foam sheet, a laminated molded product, and a method for producing the same that can be suitably used as a vehicle interior material.

In vehicle interior materials such as automobile interior materials using synthetic resins, a warm suede-like appearance is imparted to the material for texture. For example, Patent Document 1 proposes a decorative material having a suede-like appearance, which is composed of a laminate having a base material, an intermediate layer, and a surface layer, and the intermediate layer is made of a synthetic resin having a 100% modulus of 20 to 150 kg/ ^cm2 in which thermally expanded microcapsules are dispersed, and the microcapsules account for 2 to 30% by weight of the intermediate layer.

Japanese Patent Application Publication No. 10-95062

However, the decorative material described in Patent Document 1 sometimes had insufficient elasticity (cushioning properties) and abrasion resistance.

The present invention provides a laminated foam sheet and laminated molded product that have a suede-like appearance and are highly elastic and abrasion-resistant, as well as a method for producing the same.

The present invention relates to a laminated foam sheet comprising a thermoplastic resin layer and a surface treatment layer, the thermoplastic resin layer comprising a first foamed thermoplastic resin layer containing a thermoplastic resin and expanded thermally expandable microcapsules, a surface treatment layer being disposed on a first surface of the first foamed thermoplastic resin layer, the thickness of the first foamed thermoplastic resin layer being 300 μm or more and 2000 μm or less, the thickness of the surface treatment layer being 8.0 μm or more and 25 μm or less, and the arithmetic mean height Sa of the surface treatment layer side as defined by ISO 25178 being 5 μm or more and 30 μm or less.

The present invention also relates to a laminated molded product in which the laminated foam sheet is molded into a predetermined shape.

The present invention also relates to a method for producing a laminated foam sheet, which includes the steps of forming a first unfoamed thermoplastic resin sheet by forming a thermoplastic resin composition containing a thermoplastic resin and thermally expandable microcapsules into a sheet at a temperature equal to or higher than the melting point of the thermoplastic resin and lower than the expansion start temperature of the thermally expandable microcapsules, applying a surface treatment agent to one surface of the first unfoamed thermoplastic resin sheet to form a surface treatment layer, and heating the obtained laminate at a temperature equal to or higher than the expansion start temperature of the thermally expandable microcapsules to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer.

The present invention also relates to a method for producing the laminated molded body, which includes the steps of forming a first unfoamed thermoplastic resin sheet by sheet-molding a thermoplastic resin composition containing a thermoplastic resin and thermally expandable microcapsules at a temperature equal to or higher than the melting point of the thermoplastic resin and lower than the expansion start temperature of the thermally expandable microcapsules (the temperature at which the volumetric change of the thermally expandable microcapsules begins due to heating), applying a surface treatment agent to one surface of the first unfoamed thermoplastic resin sheet to form a surface treatment layer, and molding the obtained laminated body into a laminated molded body having a predetermined shape, and in the molding step of the laminated molded body, the laminated body is heated at a temperature equal to or higher than the expansion start temperature of the thermally expandable microcapsules to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer.

The present invention can provide a laminated foam sheet and a laminated molded article which have a suede-like appearance and are highly elastic and abrasion-resistant.
Furthermore, according to the production method of the present invention, it is possible to obtain a laminated foam sheet and a laminated molded product which have a suede-like appearance and are highly elastic and abrasion-resistant.

FIG. 1 is a schematic cross-sectional view of a laminated foam sheet according to an embodiment of the present invention. FIG. 1 is a schematic cross-sectional view of a laminated foam sheet according to an embodiment of the present invention. FIG. 1 is a schematic cross-sectional view of a laminated foam sheet according to an embodiment of the present invention.

The inventors of the present invention have conducted intensive research to solve the above problems. As a result, they have found that it is possible to provide a laminated foam sheet that has a suede-like appearance, high elasticity and abrasion resistance, and can be suitably used as a vehicle interior material by configuring the laminated foam sheet to include a thermoplastic resin layer and a surface treatment layer, configuring the thermoplastic resin layer to include a first foamed thermoplastic resin layer containing a thermoplastic resin and expanded thermally expandable microcapsules, disposing the surface treatment layer on the first surface of the first foamed thermoplastic resin layer, setting the thickness of the first foamed thermoplastic resin layer to 300 μm or more and 2000 μm or less, setting the thickness of the surface treatment layer to 8.0 μm or more and 25 μm or less, and setting the arithmetic mean height Sa of the surface treatment layer side as defined by ISO 25178 to 5 μm or more and 30 μm or less.

(Laminated foam sheet)
The thermoplastic resin layer includes a first foamed thermoplastic resin layer including a thermoplastic resin and expanded thermally expandable microcapsules. The first foamed thermoplastic resin layer includes expanded thermally expandable microcapsules, which imparts a fine uneven shape to the surface of the laminated foam sheet, thereby enabling the laminated foam sheet to have an appropriate rough touch and a warm suede-like appearance.

The first foamed thermoplastic resin layer preferably contains 1 to 15 parts by weight of thermally expandable microcapsules per 100 parts by weight of thermoplastic resin, more preferably 1.5 to 10 parts by weight, and even more preferably 2 to 8 parts by weight. If the content of thermally expandable microcapsules is too low, it tends to be difficult to obtain a suede-like appearance, and if the content of thermally expandable microcapsules is too high, there is a risk of poor abrasion resistance.

Thermal expandable microcapsules are capsule-shaped foaming agents that contain a liquid low-boiling point compound in a thermoplastic resin shell, and the capsules that expand when heated function as foaming agents. Specifically, thermally expandable microcapsules have a core-shell structure, with the core being made of liquid low-boiling point hydrocarbons, and the shell containing the core and made of thermoplastic resin.

The hydrocarbons that make up the core of the thermally expandable microcapsules are not particularly limited, but examples include pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, and structural isomers of these hydrocarbons.

The thermoplastic resin constituting the shell of the thermally expandable microcapsule preferably contains a nitrile monomer. Examples of nitrile monomers include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, and fumaronitrile. The thermoplastic resin constituting the shell of the thermally expandable microcapsule may further contain one or more monomers selected from the group consisting of (meth)acrylate monomers, aromatic vinyl monomers, diene monomers, vinyl monomers having a carboxyl group, and monomers having one or more reactive functional groups selected from the group consisting of methylol groups, hydroxyl groups, amino groups, epoxy groups, and isocyanate groups.

The expanded thermally expandable microcapsules are not particularly limited, but from the viewpoint of, for example, better expression of a superior touch feeling and a suede-like appearance, the average bubble diameter (also referred to as the average particle diameter) is preferably 30 μm or more, more preferably 35 μm or more, and even more preferably 40 μm or more. In addition, the expanded thermally expandable microcapsules are not particularly limited, but from the viewpoint of, for example, further improving abrasion resistance, the average bubble diameter (average particle diameter) is preferably 200 μm or less, more preferably 160 μm or less, and even more preferably 120 μm or less. Specifically, the expanded thermally expandable microcapsules have an average bubble diameter of preferably 30 μm or more and 200 μm or less, more preferably 35 μm or more and 160 μm or less, and even more preferably 40 μm or more and 120 μm or less. The average bubble diameter of the expanded thermally expandable microcapsules can be measured as described below.

When heated, the thermally expandable microcapsules usually expand to a range of approximately 3 to 5 times the average particle size when unexpanded. From the viewpoint of easily adjusting the average bubble size of the expanded thermally expandable microcapsules to the above-mentioned range, the average particle size of the thermally expandable microcapsules when unexpanded is preferably 6 μm to 50 μm, more preferably 10 μm to 45 μm, and even more preferably 15 μm to 40 μm. The average particle size of the thermally expandable microcapsules when unexpanded can be measured, for example, by observing 30 capsules at 500 times magnification (detection limit: 0.01 μm) using a digital microscope "VHX-7000" manufactured by Keyence Corporation, and taking the average value.

The thermoplastic resin in the first foamed thermoplastic resin layer is not particularly limited, and from the viewpoints of ease of imparting a suede-like appearance and softness, for example, polyolefin-based resins, vinyl chloride-based resins, olefin-based thermoplastic elastomers, etc. can be suitably used, and it is preferable that the thermoplastic resin contains one or more selected from the group consisting of olefin-based thermoplastic elastomers and polyolefin-based resins. From the viewpoints of excellent rubber elasticity at high temperatures and during long-term deformation, and high heat resistance, it is more preferable that the thermoplastic resin contains an olefin-based thermoplastic elastomer, and even more preferable that the thermoplastic resin contains an olefin-based thermoplastic elastomer and a polyolefin-based resin.

The olefin-based thermoplastic elastomer is not particularly limited and may be any of a blend type, a polymerization type (also called reactor TPO), and a dynamic crosslinking type (also called TPV). The olefin-based thermoplastic elastomer may be used alone or in combination of two or more types. From the viewpoint of cost and performance, it is preferable to use a combination of a polymerization type and a dynamic crosslinking type.

The polyolefin resin is not particularly limited as long as it is a polymer of an olefin. For example, it may be a homopolymer of an olefin such as ethylene, propylene, 1-butene, isobutene, or 4-methyl-1-pentene, a copolymer of two or more olefins, or a copolymer of an olefin and another monomer. The copolymer may be a random copolymer or a block copolymer. The copolymer may be a terpolymer. In a copolymer of an olefin and another monomer, it is desirable that the olefin is 50% by weight or more. Examples of the other monomer include dienes, cyclopentadiene, and vinyl compounds. Specific examples of the polyolefin resin include homopolypropylene, ethylene-propylene copolymer, random polypropylene (hereinafter also referred to as R-PP), block polypropylene, ethylene-1-butene copolymer, high density polyethylene, low density polyethylene, and linear low density polyethylene (hereinafter also referred to as LLDPE). The polyolefin resin may be used alone or in combination of two or more types.

The first foamed thermoplastic resin layer has a thickness of 300 μm or more and 2000 μm or less. This allows a laminated foam sheet with excellent elasticity to be obtained. From the viewpoint of elasticity, the thickness of the first foamed thermoplastic resin layer is preferably 400 μm or more, more preferably 500 μm or more, even more preferably 650 μm or more, and particularly preferably 750 μm or more. From the viewpoints of cost and sheet processability, the thickness of the first foamed thermoplastic resin layer is preferably 1800 μm or less, more preferably 1600 μm or less, and even more preferably 1400 μm or less.

In addition to the first foamed thermoplastic resin layer, the thermoplastic resin layer may further include a non-foamed thermoplastic resin layer disposed on the opposite side of the first surface on which the surface treatment layer of the first foamed thermoplastic resin layer is disposed, from the viewpoint of preventing tearing or breaking of the sheet when stretched in the vertical direction (the length direction of the sheet) or the horizontal direction (the direction perpendicular to the vertical direction). The non-foamed thermoplastic resin layer may appropriately include a thermoplastic resin listed as a thermoplastic resin used in the first foamed thermoplastic resin layer. The first foamed thermoplastic resin layer and the non-foamed thermoplastic resin layer may be directly bonded by heating the surfaces to be joined to a temperature equal to or higher than the melting point of the constituent resin and pressing them together, or may be bonded via an adhesive.

The thickness of the non-foamed thermoplastic resin layer is not particularly limited, but may be, for example, from the viewpoint of preventing tearing or breaking of the sheet when stretched in the longitudinal or transverse direction, 100 μm to 800 μm, 150 μm to 700 μm, or 200 μm to 600 μm.

The laminate sheet includes a surface treatment layer disposed on the first surface of the first foamed thermoplastic resin layer. The surface treatment agent constituting the surface treatment layer is not particularly limited, and examples thereof include water-based polyurethane dispersion (also called water-based urethane paint), solvent-based polyurethane dispersion (also called solvent-based urethane paint), etc., and may include silicone, silicone beads, urethane beads, etc. The surface treatment layer may be composed of only a top layer, or may be composed of a top layer and a primer layer. The top layer may be composed of a surface treatment agent for top, and the primer layer may be composed of a surface treatment agent for primer.

The surface treatment layer has a thickness of 8.0 μm or more and 25 μm or less. This allows the wear resistance to be increased while maintaining the suede-like appearance imparted by the first foamed thermoplastic resin layer. From the viewpoint of wear resistance, the thickness of the surface treatment layer is preferably 8.5 μm or more, more preferably 9.0 μm or more, even more preferably 9.5 μm or more, and particularly preferably 10.0 μm or more. From the viewpoint of suede-like appearance, the thickness of the surface treatment layer is preferably 20 μm or less, more preferably 18 μm or less, even more preferably 16 μm or less, and particularly preferably 14 μm or less.

In the laminated foam sheet, the arithmetic mean height Sa of the surface treatment layer side as defined by ISO 25178 is 5 μm or more and 30 μm or less. This makes it easier for the laminated foam sheet to develop a suede-like appearance and improves abrasion resistance. The arithmetic mean height Sa is preferably 8 μm or more and 25 μm or less, and more preferably 10 μm or more and 20 μm or less.

In terms of suede-like appearance and abrasion resistance, the ten-point average roughness Rzjis of the surface treatment layer side as defined by ISO 25178 is preferably 50 μm or more and 120 μm or less, more preferably 60 μm or more and 110 μm or less, and even more preferably 75 μm or more and 95 μm or less.

The laminated foam sheet may further include, but is not limited to, a cushion layer arranged on the side opposite to the side on which the surface treatment layer of the thermoplastic resin layer is arranged, in order to enhance elasticity.

The cushion layer is not particularly limited, and may be made of a material having air bubbles or spaces. Specific examples include cross-linked resin foam, polyurethane sheet, and fiber structure. Fiber structures may include nonwoven fabric and double raschel. Even when the cushion layer is made of cross-linked resin foam, it has a different structure from the thermoplastic resin layer. In one or more embodiments of the present invention, the thermoplastic resin layer is made of a first foamed thermoplastic resin layer, or is made of a first foamed thermoplastic resin layer and a non-foamed thermoplastic resin layer.

From the viewpoint of elasticity, it is preferable that the cushion layer has a compression recovery rate of 95% or more. Here, the compression recovery rate is measured under conditions similar to the compression permanent residual set test specified in JIS K6767.

The crosslinked resin foam is not particularly limited, but is preferably a crosslinked polyolefin resin foam from the viewpoint of heat resistance and surface smoothness. The crosslinked polyolefin resin foam is not particularly limited, and may be one obtained by crosslinking a polyolefin resin by a conventionally known method and then foaming. As the polyolefin resin, any of those listed as the polyolefin resins used in the first foamed thermoplastic resin layer can be appropriately used. The method for forming the crosslinked structure is not particularly limited, and examples thereof include a method of irradiating ionizing radiation such as α rays, β rays, γ rays, and electron beams, a method of irradiating ultraviolet rays, and a method using a crosslinking agent such as an organic peroxide and a silane compound. The foaming method is not particularly limited, and examples thereof include extrusion foaming, in-mold foaming, atmospheric foaming, and chemical reaction foaming. Examples of the foaming agent that can be used include inorganic gases, hydrocarbons or halogenated hydrocarbons having a boiling point of -50 to 120°C, water, and thermal decomposition type foaming agents.

The crosslinked resin foam is not particularly limited, but from the viewpoint of moldability, the degree of crosslinking may be, for example, 30% to 65%, or 40% to 55%. The degree of crosslinking of the crosslinked resin foam can be measured, for example, by the rate of weight loss after dissolving the non-crosslinked portion using an organic solvent.

The crosslinked resin foam is not particularly limited, but from the viewpoint of flexibility and cushioning, the expansion ratio may be, for example, from 5 to 40. The expansion ratio of the crosslinked resin foam can be calculated, for example, by measuring the specific volumes (unit: ^cm3 /g) of the expandable resin sheet before foaming and the crosslinked resin foam sheet, and calculating the ratio by dividing the specific volume of the crosslinked resin foam sheet by the specific volume of the expandable resin sheet before foaming.

The crosslinked resin foam may contain additives such as foaming aids, softeners, lubricants, antioxidants, antistatic agents, flame retardants, UV absorbers, light stabilizers, colorants, and inorganic fillers, as necessary.

The thickness of the cushion layer is not particularly limited, but may be, for example, from the viewpoint of elasticity, 0.5 mm or more and 5.0 mm or less, 1.0 mm or more and 4.5 mm or less, or 1.5 mm or more and 4.0 mm or less.

The thermoplastic resin layer and the cushion layer may be joined directly by heating the surfaces to be joined above the melting point of the constituent resins, or may be joined via an adhesive.

From the viewpoint of excellent elasticity, the laminated foam sheet preferably has a 0.1 mm compression hardness measured with the surface treatment layer as the load surface of 25 N or less, more preferably 20 N or less, and even more preferably 15 N or less. The lower limit of the 0.1 mm compression hardness of the laminated foam sheet is not particularly limited, but may be 1 N or more from the viewpoint of accelerating the compression recovery rate. The compression hardness can be measured as described below.

From the viewpoint of excellent elasticity, the laminated foam sheet preferably has a 25% compression hardness measured with the surface treatment layer as the load surface of 100N or less, more preferably 95N or less, and even more preferably 85N or less. The lower limit of the 25% compression hardness of the laminated foam sheet is not particularly limited, but may be 10N or more from the viewpoint that the compression hardness improves as the thickness of the laminated foam sheet decreases. In addition, from the viewpoint of excellent elasticity, the laminated foam sheet preferably has a 50% compression hardness measured with the surface treatment layer as the load surface of 300N or less, more preferably 280N or less, and even more preferably 260N or less. The lower limit of the 50% compression hardness of the laminated foam sheet is not particularly limited, but may be 30N or more from the viewpoint that the compression hardness improves as the thickness of the laminated foam sheet decreases. The compression hardness can be measured as described below.

In the laminated foam sheet, from the viewpoint of excellent elasticity, the cross-sectional porosity of the thermoplastic resin layer is preferably 5% or more and 65% or less, more preferably 10% or more and 60% or less, even more preferably 15% or more and 55% or less, and particularly preferably 25% or more and 50% or less. Specifically, the cross-sectional porosity can be measured as described below.

From the viewpoint of abrasion resistance, the laminated foam sheet preferably has a Shore A hardness of 30 or more and 80 or less on the surface treatment layer side, more preferably 35 or more and 75 or less, and even more preferably 40 or more and 60 or less. Specifically, the Shore A hardness can be measured as described below.

From the viewpoint of abrasion resistance, in a Taber abrasion test conforming to JIS K 7204:1999 (wear wheel CS-10, load 4.9 N), the laminated foam sheet preferably has a rotation speed of 100 or more, more preferably 200 or more, even more preferably 300 or more, even more preferably 400 or more, and particularly preferably 500 or more.

From the viewpoint of abrasion resistance, the laminated foam sheet preferably has a peel strength of 2 N/mm or more, more preferably 3 N/mm or more, even more preferably 4 N/mm or more, and particularly preferably 5 N/mm or more, in a sample width of 15 mm in a 180° peel test between the surface treatment layer and the thermoplastic resin. The peel strength between the surface treatment layer and the thermoplastic resin in the laminated foam sheet can be measured as described below.

In order to easily achieve a suede-like appearance, the gloss (luster) of the surface treatment layer of the laminated foam sheet is preferably 2.0 or less, more preferably 1.8 or less, and even more preferably 1.4 or less. The gloss of the surface treatment layer of the laminated foam sheet can be measured as described below.

From the viewpoint of excellent secondary moldability such as vacuum molding, the laminated foam sheet preferably has a tensile elongation of 60% or more at 160°C, more preferably 70% or more, and even more preferably 80% or more. The upper limit of the tensile elongation of the laminated foam sheet at 160°C is not particularly limited, but may be 400% or less from the viewpoint of the limit of the complicated shape of the mold. From the viewpoint of excellent secondary moldability such as vacuum molding, the laminated foam sheet preferably has a tensile stress of 20 kPa or more at 160°C, more preferably 25 kPa or more, even more preferably 30 kPa or more, and particularly preferably 35 kPa or more. The upper limit of the tensile stress of the laminated foam sheet at 160°C is not particularly limited, but may be 280 kPa or less from the viewpoint of the amount of drawdown during molding. Specifically, the tensile elongation and tensile stress of the laminated foam sheet at 160°C can be measured as described below.

From the viewpoint of excellent secondary moldability such as vacuum molding, the laminated foam sheet preferably has a tensile elongation of 150% or more at 23°C, more preferably 200% or more, and even more preferably 260% or more. The upper limit of the tensile elongation of the laminated foam sheet at 23°C is not particularly limited, but may be 700% or less from the viewpoint of molding with a low expansion rate and pasting processing. From the viewpoint of excellent secondary moldability such as vacuum molding, the laminated foam sheet preferably has a tensile stress of 1.0 MPa or more at 23°C, more preferably 1.2 MPa or more, even more preferably 1.5 MPa or more, and particularly preferably 1.8 MPa or more. The upper limit of the tensile stress of the laminated foam sheet at 23°C is not particularly limited, but may be 9.9 MPa or less from the viewpoint of no tearing due to sewing processing. Specifically, the tensile elongation and tensile stress at 23°C can be measured as described below.

Figure 1 is a schematic cross-sectional view of an example of a laminated foam sheet of the present invention. In this embodiment, the laminated foam sheet 1 includes a thermoplastic resin layer 2 and a surface treatment layer 3, and the thermoplastic resin layer 2 is composed of a first foamed thermoplastic resin layer 20 including a thermoplastic resin and expanded thermally expandable microcapsules 10. The surface treatment layer 3 is disposed on a first surface of the first foamed thermoplastic resin layer 20.

Figure 2 is a schematic cross-sectional view of an example of a laminated foam sheet of the present invention. In this embodiment, the laminated foam sheet 11 includes a thermoplastic resin layer 2 and a surface treatment layer 3, and the thermoplastic resin layer 2 is composed of a first foamed thermoplastic resin layer 20 containing a thermoplastic resin and expanded thermally expandable microcapsules 10, and an unfoamed thermoplastic resin layer 30. The surface treatment layer 3 is disposed on a first surface of the first foamed thermoplastic resin layer 20.

Figure 3 is a schematic cross-sectional view of an example of a laminated foam sheet of the present invention. In this embodiment, the laminated foam sheet 21 includes a thermoplastic resin layer 2, a surface treatment layer 3, and a cushion layer 4, and the thermoplastic resin layer 2 is composed of a first foamed thermoplastic resin layer 20 including a thermoplastic resin and expanded thermally expandable microcapsules 10. The surface treatment layer 3 is disposed on a first surface of the first foamed thermoplastic resin layer 20. The cushion layer 4 is disposed on the side of the thermoplastic resin layer 2 opposite to the side on which the surface treatment layer 3 is disposed.

The laminated foam sheet may include a first foamed thermoplastic resin layer, a non-foamed thermoplastic resin layer, and a cushion layer. In this case, the order is the surface treatment layer, the thermoplastic resin layer, and the cushion layer, i.e., the surface treatment layer, the first foamed thermoplastic resin layer, the non-foamed thermoplastic resin layer, and the cushion layer.

The laminated foam sheet can be suitably used, for example, as a skin material for vehicle interior materials, although there is no particular limitation. Examples of vehicle interior materials include instrument panels, door trims, trunk trims, seats, pillar covers, ceiling materials, rear trays, console boxes, airbag covers, arm rests, head rests, meter covers, crash pads, etc., of vehicles such as automobiles.

(Method for producing laminated foam sheet)
The laminated foam sheet is not particularly limited, but can be produced, for example, by sheet-molding a thermoplastic resin composition containing a thermoplastic resin and thermally-expandable microcapsules at a temperature equal to or higher than the melting point of the thermoplastic resin and lower than the expansion start temperature of the thermally-expandable microcapsules to form a first unfoamed thermoplastic resin sheet, applying a surface treatment agent to one surface of the first unfoamed thermoplastic resin sheet obtained to form a surface treatment layer, and heating the obtained laminate at a temperature equal to or higher than the expansion start temperature of the thermally-expandable microcapsules to expand the thermally-expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer.

The above-mentioned thermoplastic resins and thermally expandable microcapsules can be used as appropriate.

When the thermoplastic resin contains multiple thermoplastic resins, "above the melting point of the thermoplastic resin" in the process of forming the first unfoamed thermoplastic resin sheet means above the melting point of the thermoplastic resin with the highest melting point.

The thermally expandable microcapsules are not particularly limited, but from the viewpoint of suppressing foaming in the process of forming the first unfoamed thermoplastic resin sheet, the expansion start temperature (also referred to as the initial decomposition temperature) is preferably 160°C or higher, more preferably 170°C or higher, more preferably 180°C or higher, and particularly preferably 185°C or higher. Furthermore, from the viewpoint of facilitating the formation of the first foamed thermoplastic resin layer, the temperature may be 215°C or lower, or may be 210°C or lower.

The thermally expandable microcapsules are not particularly limited, but from the viewpoint of easily forming the first foamed thermoplastic resin layer while suppressing foaming in the process of forming the first unfoamed thermoplastic resin sheet, it is preferable that the expansion start temperature is 185°C or higher and 215°C or lower, and more preferably 190°C or higher and 215°C or lower.

The thermally expandable microcapsules are not particularly limited, but from the viewpoint of easily forming the first foamed thermoplastic resin layer while suppressing foaming in the formation process of the first unfoamed thermoplastic resin sheet, the maximum expansion temperature (also referred to as the maximum foaming temperature) is preferably 190°C or higher and 240°C or lower, more preferably 195°C or higher and 235°C or lower, and even more preferably 200°C or higher and 230°C or lower.

The expansion start temperature and maximum expansion temperature of thermally expandable microcapsules are measured using a thermomechanical analyzer (TMA).

The thermoplastic resin composition may contain one or more additives such as softeners, inorganic fillers, antioxidants, light stabilizers, UV absorbers, antistatic agents, lubricants, and colorants, as necessary. The amount of the additives may be, for example, 10 parts by weight or less per 100 parts by weight of the thermoplastic resin.

The sheet molding is not particularly limited, and may be calendar molding or extrusion molding.

As the surface treatment agent, the above-mentioned ones can be appropriately used. From the viewpoint of abrasion resistance, it is preferable to use a surface treatment agent whose coating film has a tensile stress of 3 MPa or more and a tensile elongation of 30% or more measured in a tensile test performed under conditions of 23°C, 65% RH, and a tensile speed of 500 mm/min, and whose peel strength of a sample width of 15 mm measured in a 180° peel test is 2 N/mm or more. The tensile stress of the coating film of the surface treatment agent is more preferably 4 MPa or more and 35 MPa or less. The tensile elongation of the coating film of the surface treatment agent is more preferably 35% or more and 500% or less. The peel strength of the coating film of the surface treatment agent is more preferably 3 N/mm or more and 25 N/mm or less. Specifically, the tensile stress, tensile elongation, and peel strength of the coating film of the surface treatment agent at 23°C can be measured as described below.

The surface treatment layer can be formed, for example, by applying a surface treatment agent such as a polyurethane dispersion for the top coat and for the primer to one surface of the first unfoamed thermoplastic resin sheet and drying the applied surface at a temperature of 50°C or higher and 140°C or lower. Coating and drying may be performed two or more times.

When the thermoplastic resin layer includes an unfoamed thermoplastic resin layer in addition to the first foamed thermoplastic resin layer, in the step of forming the first unfoamed thermoplastic resin sheet, a two-layer sheet of the first unfoamed thermoplastic resin sheet and the unfoamed thermoplastic resin sheet can be formed by co-extruding a thermoplastic resin composition including a thermoplastic resin and thermally expandable microcapsules and a thermoplastic resin composition including a thermoplastic resin (not including a foaming agent) at a temperature lower than the expansion start temperature of the thermally expandable microcapsules. Alternatively, the first unfoamed thermoplastic resin sheet obtained by calendar molding or extrusion molding may be thermally laminated on the surface of an unfoamed thermoplastic resin sheet obtained by sheet molding of a thermoplastic resin composition including a thermoplastic resin (not including a foaming agent).

When the laminated foam sheet includes a cushion layer, after forming the surface treatment layer, the resulting laminate is heated at a temperature equal to or higher than the expansion start temperature of the thermally expandable microcapsules to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form the first foamed thermoplastic resin layer. When this is done, the cushioning material such as a crosslinked resin foam that forms the cushion layer can be bonded directly or via an adhesive to the thermoplastic resin layer.

(Laminated Molded Product and Manufacturing Method)
The laminated molded body is a laminated foam sheet molded into a predetermined shape. When the laminated molded body is a skin material for a vehicle interior material, the laminated foam sheet can be molded to match the shape of the vehicle interior material. Examples of the vehicle interior material include instrument panels, door trims, trunk trims, seats, pillar covers, ceiling materials, rear trays, console boxes, airbag covers, armrests, headrests, meter covers, crash pads, etc. of vehicles such as automobiles.

The laminated molded body may be produced by directly molding a laminated foam sheet. Alternatively, the laminated molded body is produced by forming a first unfoamed thermoplastic resin sheet by sheet molding a thermoplastic resin composition containing a thermoplastic resin and a thermally expandable microcapsule at a temperature equal to or higher than the melting point of the thermoplastic resin and lower than the initial decomposition temperature of the thermally expandable microcapsule, applying a surface treatment agent to one surface of the first unfoamed thermoplastic resin sheet to form a surface treatment layer, and heating the resulting laminate at a temperature equal to or higher than the maximum foaming temperature of the thermally expandable microcapsule to expand the thermally expandable microcapsule in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer and mold a predetermined shape. The molding of the laminated molded body can be performed by vacuum molding, and male vacuum molding is preferable to obtain a more suede-like texture.

The present invention will be described in more detail below using examples. Note that the present invention is not limited to the following examples.

The measurement and evaluation methods used in the examples and comparative examples are explained below.

(Tensile test and peel test of coating film of surface treatment agent)
The surface treatment agent was thinly applied to a release film using a bar coater and dried in an oven (solvent-based: 80°C, 1 min, aqueous-based 80°C, 2 min) to obtain a coating film consisting only of the surface treatment agent with a coating thickness of 15 to 20 μm. The coating film was then punched out using a dumbbell No. 2, and a tensile test was performed using the obtained test piece at a temperature of 23°C and 65% RH at a tensile speed of 500 mm/min to measure the tensile stress and tensile elongation.
Also, under conditions of a temperature of 23° C. and a relative humidity of 65%, a hot melt tape (iron 180° C., fixed for 3 minutes) was applied to the coating film of the surface treatment agent, and a 180° peel test was carried out to measure the peel strength.

(Arithmetic mean height Sa and ten-point mean roughness Rzjis)
The arithmetic mean height Sa and ten-point mean roughness Rzjis of the surface treatment layer side were measured using a VR-5000 manufactured by Keyence Corporation in accordance with ISO 25178.

(Cross-sectional void ratio)
The laminated foam sheet was cut in the thickness direction perpendicularly from the surface treatment agent surface with a cutter, and the cross section of the laminated foam sheet was observed at a magnification of 150 times using a digital microscope ("VHX-7000" manufactured by Keyence Corporation). In the obtained OPT-SEM (Optical Shadow Effect Mode) image of the thermoplastic resin layer, the area of a designated range was measured to obtain the total area, and the bubble area in the designated range was measured to calculate the cross-sectional bubble ratio by the following mathematical formula 1.
[Formula 1]
Cross-sectional bubble rate (%) = bubble area / total area × 100

(Shore A hardness)
In accordance with JIS K 7215, an "Asker Rubber Hardness Tester Type A" manufactured by Kobunshi Keiki Co., Ltd. was used, and the scale was read immediately after the indenter was brought into contact with the sample three times, and the average value was taken as the Shore A hardness.

(Average bubble diameter of expanded thermally expansive microcapsules)
Thermally expandable microcapsules heated to or above their expansion temperature, or foamed sheets containing thermally expandable microcapsules, or laminated foamed sheets were cut with a cutter perpendicular to the surface treatment layer in the thickness direction, and 30 air bubbles were observed on the cross section at a magnification of 50 times using a Keyence Corporation "VHX-7000". The air bubble diameters were measured using the in-machine measuring system and averaged.

(Compression Hardness)
Measurement was performed based on JIS K 6767.
(1) The laminated foam sheet was cut into a 20 mm square, and six sheets were stacked to prepare a sample. The initial thickness of the sample was measured with a vernier caliper.
(2) The sample was set in a compression tester (Shimadzu Corporation, model number "AGM-1"), and an initial load of 0.5 N was applied via a φ35 pressure plate with the surface treatment layer as the load surface, and this position was designated as the origin.
(3) Pressurization was performed at a constant speed (1 mm/min), and the stresses at 0.1 mm compression (0.1 mm from the origin), 25% compression (1.265 mm from the origin), and 50% compression (2.53 mm from the origin) were measured. The values measured by the in-machine measuring system were regarded as the compression hardness.

(Tensile test and peel test of laminated foam sheet)
The laminated foam sheet was punched out with a No. 2 dumbbell, and the obtained test piece was subjected to a tensile test at a tensile speed of 500 mm/min to measure the tensile stress and tensile elongation.
In addition, a hot melt tape was used to attach the hot melt tape (iron 180° C., fixed for 3 minutes) to the surface treatment layer side of the laminated foam sheet, and a 180° peel test was carried out to measure the peel strength.

(Wear test)
A Taber abrasion test (abrasion wheel CS-10, load 4.9 N) according to JIS K 7204:1999 was carried out, the number of revolutions was measured, and the result was judged according to the following criteria.
<Judgment criteria>
A: The coating film of the surface treatment layer is not peeled off and is unchanged.
B: The coating film of the surface treatment layer is not peeled off, and slight whitening is observed.
C: The coating film of the surface treatment layer is partially peeled off and whitening is observed.
D: The coating film of the surface treatment layer was peeled off, and the substrate was visible.

(exterior)
The laminated foam sheet was visually observed by three examiners and judged according to the following criteria. When two or more examiners agreed on the judgment or when the judgments of the three examiners were different, the judgment of the middle examiner of the three examiners was used as the appearance judgment.
A: Fuzzy white, warm, suede-like appearance.
B: There is fuzzy whitening and it looks like suede.
C: Looks slightly fluffy and slightly suede-like.
D: Not fuzzy and does not look suede-like.

(Gross)
The 60° specular gloss of the surface treatment layer was measured using "UNI GLOSS 60Plus" manufactured by Konica Minolta in accordance with JIS Z8741, and the average value of three measurements was taken as the gloss.

(Secondary formability)
Using a test vacuum molding machine, both sides of the laminated foam sheet were heated to 180°C to 230°C, and vacuum molded into a box shape measuring 150 mm in length, 100 mm in width and 50 mm in depth, and evaluated according to the following criteria.
A: Appearance and shape are good.
B: Appearance and shape are somewhat good.
C: Defects occur in either appearance or shape.
D: Poor appearance and shape due to breakage.

The thermoplastic resin compositions used in the examples and comparative examples will be described below.
Thermoplastic resin composition 1: 25.0 parts by weight of dynamically crosslinked olefin-based thermoplastic elastomer (Milastomer (registered trademark) "5030NHS", manufactured by Mitsui Chemicals, Inc., partially crosslinked, melting point 158°C, Shore A hardness 50), 25.0 parts by weight of dynamically crosslinked olefin-based thermoplastic elastomer (Milastomer (registered trademark) "8030NHS", manufactured by Mitsui Chemicals, Inc., partially crosslinked, melting point 158°C, Shore A hardness 85), 25.0 parts by weight of dynamically crosslinked olefin-based thermoplastic elastomer (Sumitomo Chemical To 100 parts by weight of a thermoplastic resin (mixed resin) consisting of 25.0 parts by weight of Esporex (registered trademark "WT485A" manufactured by Sumitomo Chemical Co., Ltd., melting point 157°C, partially crosslinked, Shore A hardness 60), 5.0 parts by weight of random polypropylene ("B-241" manufactured by Prime Polymer Co., Ltd., melting point 141°C), and 20.0 parts by weight of linear low-density polyethylene ("FW201-0" manufactured by Sumitomo Chemical Co., Ltd., melting point 119°C), 0.75 parts by weight in total of a lubricant, an antioxidant, and an ultraviolet absorber, and 6.0 parts by weight of a pigment were added. Thermoplastic resin composition 2: 85.0 parts by weight of dynamically crosslinked olefin thermoplastic elastomer (Mitsubishi Chemical Corporation, TREXPRENE "TV-010N", partially crosslinked, melting point 118°C, Shore A hardness 63), 5.0 parts by weight of α-olefin copolymer (Mitsui Chemicals, Inc., Tafmer (registered trademark) "PN3525", melting point 160°C, Shore A hardness 72), 10.0 parts by weight of olefin block copolymer (Dow Chemical Company, INFUSE "9107", melting point 121°C, Shore A hardness 60), 100 parts by weight of thermoplastic resin (mixed resin) containing 0.75 parts by weight in total of lubricant, antioxidant and ultraviolet absorber, and 6.0 parts by weight of pigment. Thermoplastic resin composition 3: 40.0 parts by weight of dynamically crosslinked olefin-based thermoplastic elastomer (TREXPRENE "TV-010N", manufactured by Mitsubishi Chemical Corporation, partially crosslinked, melting point 118°C, Shore A hardness 63), 40.0 parts by weight of dynamically crosslinked olefin-based thermoplastic elastomer (Santoprene "201-55", manufactured by Exxon Mobil Corporation, fully crosslinked, melting point 152°C, Shore A hardness 59), α-olefin copolymer (Tafmer (registered trademark), manufactured by Mitsui Chemicals, Inc.) A thermoplastic resin (mixed resin) consisting of 10.0 parts by weight of olefin block copolymer (Dow Chemical Company, INFUSE "9107", melting point 121°C, Shore A hardness 60), 5.0 parts by weight of olefin block copolymer (Sumitomo Chemical Company, "FW201-0", melting point 119°C) and 5.0 parts by weight of linear low-density polyethylene (Sumitomo Chemical Company, "FW201-0", melting point 119°C) was added to 100 parts by weight of the thermoplastic resin (mixed resin) consisting of 10.0 parts by weight of olefin block copolymer (Dow Chemical Company, INFUSE "9107", melting point 121°C, Shore A hardness 60), 5.0 parts by weight of linear low-density polyethylene (Sumitomo Chemical Company, "FW201-0", melting point 119°C), and 0.75 parts by weight in total of lubricant, antioxidant and ultraviolet absorber, and 6.0 parts by weight of pigment were added.

In the examples and comparative examples, the foaming agents shown in Table 1 below were used. As the masterbatch for thermally expandable microcapsules 1, a masterbatch was used that used polyethylene (manufactured by Tosoh Corporation, product name "Petrothene 248") as the carrier resin and contained 50% by weight of thermally expandable microcapsules 1. As the masterbatch for thermally expandable microcapsules 2, a masterbatch was used that used TPO (manufactured by ExxonMobil Japan, product name "Vistamax 3000") as the carrier resin and contained 50% by weight of thermally expandable microcapsules 2.

In the examples and comparative examples, the surface treatment agent (urethane paint) shown in Table 2 below was used. In addition, a tensile test at 23°C of the coating film of the surface treatment agent was performed as described above, and the results are shown in Table 3 below.

Example 1
(Preparation of Laminated Foam Sheet)
A master batch of thermally expandable microcapsules 1 was added to thermoplastic resin composition 1 so that the blending amount of thermally expandable microcapsules 1 was as shown in Table 4 below per 100 parts by weight of the thermoplastic resin (mixed resin) in thermoplastic resin composition 1. The obtained thermoplastic resin composition was kneaded at 185°C and calender molded to form a first unfoamed thermoplastic resin sheet.
A surface treatment agent was applied to one surface of the obtained first unfoamed thermoplastic resin sheet, starting from the primer layer, under the conditions shown in Table 4 below (drying temperature 120°C) to form a surface treatment layer having a top layer and a primer layer.
The obtained laminate was heated at a temperature of 230°C to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer (thickness: approximately 688 μm), thereby obtaining a laminated foamed sheet having the structure shown in Figure 1.
(Preparation of laminated molded body)
The laminated foamed sheet obtained above was heated to a surface temperature of 220° C. or higher using an infrared heater installed in a vacuum molding machine, pressed against a mold, and the shape was maintained by vacuum drawing. After cooling and demolding, a laminated molded body was produced.

Example 2
The thermoplastic resin composition 1 was kneaded at 190 ° C. and calendered to obtain a non-foamed thermoplastic resin sheet (non-foamed thermoplastic resin layer, thickness about 600 μm). On one surface of the non-foamed thermoplastic resin sheet, the thermoplastic resin composition containing the thermally expandable microcapsules 1 was kneaded at 185 ° C. and thermally laminated by calendering to form a laminate of the non-foamed thermoplastic resin sheet and the first unfoamed thermoplastic resin sheet. The thermoplastic resin composition containing the thermally expandable microcapsules 1 was obtained by adding a master batch of the thermally expandable microcapsules 1 to the thermoplastic resin composition 1 so that the amount of the thermally expandable microcapsules 1 was the amount shown in Table 4 below relative to 100 parts by weight of the thermoplastic resin (mixed resin) in the thermoplastic resin composition 1.
A surface treatment layer having a top layer and a primer layer was formed in the same manner as in Example 1 on one surface of the first unfoamed thermoplastic resin sheet of the obtained laminate.
The obtained laminate was heated at 230°C to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer (thickness: approximately 688 μm), thereby obtaining a laminated foamed sheet having the structure shown in Figure 2.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

Example 3
(Preparation of Laminated Foam Sheet)
In the same manner as in Example 1, a laminate of a first unfoamed thermoplastic resin sheet and a surface treatment layer was obtained.
The obtained laminate was laminated with a crosslinked resin foam so that the crosslinked resin foam was located on the opposite side to the side where the surface treatment layer of the first unfoamed thermoplastic resin sheet was disposed, and heated at 230° C. to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer (thickness: about 688 μm) and bond the first foamed thermoplastic resin layer to the crosslinked resin foam, thereby obtaining a laminated foam sheet having the structure shown in Fig. 3. As the crosslinked resin foam, a crosslinked polyolefin resin foam ("JP17-15025" manufactured by Toray Industries, Inc.), with a crosslinking degree of 43%, an expansion ratio of 15 times, a thickness of 2.5 mm, and a compression recovery rate of 92%) was used.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

Example 4
(Preparation of Laminated Foam Sheet)
A laminate of a non-foamed thermoplastic resin sheet (non-foamed thermoplastic resin layer, thickness approximately 500 μm) and a first unfoamed thermoplastic resin sheet was formed in the same manner as in Example 2, except that thermoplastic resin composition 2 was used instead of thermoplastic resin composition 1 and the amount of thermally expandable microcapsules 1 was set as shown in Table 4 below.
A surface treatment agent was applied from the primer layer to the surface of the first unfoamed thermoplastic resin sheet of the obtained laminate opposite to the side on which the unfoamed thermoplastic resin sheet was placed (drying temperature 130°C) under the conditions shown in Table 4 below, to form a surface treatment layer having a top layer and a primer layer.
The obtained laminate was heated at 230°C to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer (thickness: approximately 690 μm), thereby obtaining a laminated foamed sheet having the structure shown in Figure 2.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

Example 5
(Preparation of Laminated Foam Sheet)
A master batch of thermally expandable microcapsules 1 was added to thermoplastic resin composition 2 so that the blending amount of thermally expandable microcapsules 1 was as shown in Table 4 below per 100 parts by weight of the thermoplastic resin (mixed resin) in thermoplastic resin composition 2. The obtained thermoplastic resin composition was kneaded at 185°C and calendar molded to form a first unfoamed thermoplastic resin sheet.
A surface treatment agent was applied to one surface of the obtained first unfoamed thermoplastic resin sheet, starting from the primer layer, under the conditions shown in Table 4 below (drying temperature 120°C) to form a surface treatment layer having a top layer and a primer layer.
The obtained laminate was heated at a temperature of 230°C to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer (thickness: approximately 1,187 μm), thereby obtaining a laminated foamed sheet having the structure shown in Figure 1.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

Example 6
(Preparation of Laminated Foam Sheet)
A laminate of a non-foamed thermoplastic resin sheet (non-foamed thermoplastic resin layer, thickness approximately 400 μm) and a first unfoamed thermoplastic resin sheet was formed in the same manner as in Example 4, except that thermoplastic resin composition 3 was used instead of thermoplastic resin composition 2.
A surface treatment agent was applied to one surface of the obtained first unfoamed thermoplastic resin sheet, starting from the primer layer, under the conditions shown in Table 4 below (drying temperature 120°C) to form a surface treatment layer having a top layer and a primer layer.
The obtained laminate was heated at a temperature of 230°C to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer (thickness: approximately 690 μm), thereby obtaining a laminated foamed sheet having the structure shown in Figure 2.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

(Example 7)
(Preparation of Laminated Foam Sheet)
A laminated foam sheet having the structure shown in FIG. 2 was produced in the same manner as in Example 4, except that the surface treatment agents shown in Table 1 below were used.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

(Example 8)
A laminated foam and laminated molded body having the structure shown in FIG. 1 were prepared in the same manner as in Example 1, except that the thermal expansion microcapsules 1 were mixed in the amount shown in Table 4 below and the surface treatment agent was applied under the conditions shown in Table 4 below.

(Comparative Example 1)
(Preparation of Laminated Sheet)
Thermoplastic resin composition 1 was kneaded at 185° C. and calender molded to obtain a non-foamed thermoplastic resin sheet.
A surface treatment agent was applied to one surface of the obtained non-foamed thermoplastic resin sheet starting from the primer layer under the conditions shown in Table 5 below (drying temperature 120°C) to form a surface treatment layer having a top layer and a primer layer, thereby obtaining a laminated sheet.
(Preparation of laminated molded body)
A laminated molded product was produced in the same manner as in Example 1, except that the laminated sheet obtained above was used.

(Comparative Example 2)
(Preparation of Laminated Sheet)
Thermoplastic resin composition 1 was kneaded at 185° C. and calender molded to obtain a non-foamed thermoplastic resin sheet.
A surface treatment agent was applied to one surface of the obtained non-foamed thermoplastic resin sheet starting from the primer layer under the conditions shown in Table 5 below (drying temperature 120°C) to form a surface treatment layer having a top layer and a primer layer, thereby obtaining a laminated sheet.
(Preparation of laminated molded body)
A laminated molded product was produced in the same manner as in Example 1, except that the laminated sheet obtained above was used.

(Comparative Example 3)
(Preparation of Laminated Foam Sheet)
Thermoplastic resin composition 2 was kneaded at 185 ° C. and calendered to obtain a non-foamed thermoplastic resin sheet (thickness 401 μm). On one surface of the non-foamed thermoplastic resin sheet, a thermoplastic resin composition containing thermally expandable microcapsules 1 was kneaded at 185 ° C. and thermally laminated by calendering to form a laminate of a non-foamed thermoplastic resin sheet and a first unfoamed thermoplastic resin sheet. The thermoplastic resin composition containing thermally expandable microcapsules 1 was obtained by adding a master batch of thermally expandable microcapsules 1 to thermoplastic resin composition 2 so that the amount of thermally expandable microcapsules 1 was the amount shown in Table 5 relative to 100 parts by weight of the thermoplastic resin (mixed resin) in the thermoplastic resin composition 2.
Thermoplastic resin composition 2 was kneaded at 180°C on the surface of the first unfoamed thermoplastic resin sheet of the obtained laminate opposite the side on which the non-foamed thermoplastic resin sheet was placed, and then thermally laminated by calendar molding to obtain a three-layer laminate consisting of a non-foamed thermoplastic resin sheet, a first unfoamed thermoplastic resin sheet, and a non-foamed thermoplastic resin sheet (thickness 1,192 μm).
A surface treatment agent was applied from the primer layer onto the surface of one of the unfoamed thermoplastic resin sheets of the obtained laminate opposite the side in contact with the first unfoamed thermoplastic resin sheet under the conditions shown in Table 5 below (drying temperature 120°C), thereby forming a surface treatment layer having a top layer and a primer layer.
The obtained laminate was heated at 230°C to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer (thickness 1504 μm), thereby obtaining a laminated foamed sheet.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

(Comparative Example 4)
A laminated foam sheet and a laminated molded body were produced in the same manner as in Example 1, except that the surface treatment agent was applied from the primer layer under the conditions shown in Table 5 below (drying temperature 120° C.) to form a surface treatment layer having a top layer and a primer layer.

(Comparative Example 5)
A laminated foam sheet and a laminated molded body were produced in the same manner as in Example 1, except that the surface treatment agent was applied from the primer layer under the conditions shown in Table 5 below (drying temperature 120° C.) to form a surface treatment layer having a top layer and a primer layer.

(Comparative Example 6)
(Preparation of Laminated Foam Sheet)
A powder type chemical foaming agent was added to thermoplastic resin composition 3 so that the foaming agent was blended in an amount shown in the following Table 5 per 100 parts by weight of the thermoplastic resin (mixed resin) in thermoplastic resin composition 3. The obtained thermoplastic resin composition was kneaded at 175°C and calender molded to form a first unfoamed thermoplastic resin sheet.
A surface treatment layer having a top layer and a primer layer was formed in the same manner as in Example 1 on one surface of the obtained first unfoamed thermoplastic resin sheet.
The obtained laminate was heated at a temperature of 215° C. to foam the foaming agent in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer (thickness: about 1,300 μm), thereby obtaining a laminated foamed sheet having the structure shown in FIG. 1.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

(Comparative Example 7)
(Preparation of Laminated Foam Sheet)
Thermoplastic resin composition 1 was kneaded at 180° C. and calendered to form a non-foamed thermoplastic resin sheet.
A surface treatment agent was applied to one surface of the obtained non-foamed thermoplastic resin sheet starting from the primer layer under the conditions shown in Table 5 below (drying temperature 120°C) to form a surface treatment layer having a top layer and a primer layer. In this case, the surface treatment agent for the primer layer was a surface treatment agent containing thermally expandable microcapsules that had been previously added with 5% by weight of the wet application amount (g/ ^m2 ) and mixed by stirring.
The obtained laminate was heated at a temperature of 230°C to expand the thermally expandable microcapsules in the primer layer of the surface treatment agent, thereby forming a foamed surface treatment agent primer layer (thickness: approximately 49 μm), thereby obtaining a laminated foamed sheet having a structure in which the primer layer forms a foamed layer.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

(Comparative Example 8)
(Preparation of Laminated Foam Sheet)
Thermoplastic resin composition 1 was kneaded at 180° C. and calendered to form a non-foamed thermoplastic resin sheet.
A surface treatment agent was applied to one surface of the obtained non-foamed thermoplastic resin sheet starting from the primer layer under the conditions shown in Table 5 below (drying temperature 120°C) to form a surface treatment layer having a top layer and a primer layer. In this case, for the top layer surface treatment agent, a surface treatment agent containing thermally expandable microcapsules that had been previously added with 5% by weight of the wet application amount (g/ ^m2 ) and mixed by stirring was used.
The obtained laminate was heated at a temperature of 230°C to expand the thermally expandable microcapsules in the top layer of the surface treatment agent, thereby forming a foamed surface treatment agent top layer (thickness: approximately 51 μm), thereby obtaining a laminated foam sheet having a structure in which the top layer forms a foamed layer.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

(Comparative Example 9)
A master batch of thermally expandable microcapsules 2 was added to thermoplastic resin composition 1 so that the blending amount of thermally expandable microcapsules 2 was as shown in Table 5 below per 100 parts by weight of the thermoplastic resin (mixed resin) in thermoplastic resin composition 1. When the obtained thermoplastic resin composition was kneaded at 158°C and calendar molded, the thermally expandable microcapsules foamed (expanded), and a first unfoamed thermoplastic resin sheet could not be formed.

(Comparative Example 10)
The thermally expandable microcapsules 3 were added to the thermoplastic resin composition 1 in an amount shown in Table 5 below, per 100 parts by weight of the thermoplastic resin (mixed resin) in the thermoplastic resin composition 1. When the obtained thermoplastic resin composition was kneaded at 180°C and calendar molded, the thermally expandable microcapsules foamed (expanded), and a first unfoamed thermoplastic resin sheet could not be formed.

(Comparative Example 11)
(Preparation of Laminated Foam Sheet)
A laminate of an unfoamed thermoplastic resin sheet (thickness 600 μm) and a first unfoamed thermoplastic resin sheet was formed in the same manner as in Example 4, except that thermoplastic resin composition 3 was used instead of thermoplastic resin composition 2.
A surface treatment agent (primer) and a surface treatment agent having self-repairing properties (manufactured by DIC Corporation, product numbers "BX-800S" and "DN-902S" mixed at a ratio of 100:2.8) shown in Table 5 below were applied to the surface of the first unfoamed thermoplastic resin sheet of the obtained laminate on the side not in contact with the unfoamed thermoplastic resin sheet under the conditions shown in Table 5 below (drying temperature 120° C.) to form a surface treatment layer.
The obtained laminate was heated at a temperature of 230°C, causing the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to expand, forming a first foamed thermoplastic resin layer (thickness 1,100 μm), and obtaining a laminated foamed sheet.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

(Comparative Example 12)
(Preparation of Laminated Foam Sheet)
A laminate of an unfoamed thermoplastic resin sheet (thickness 500 μm) and a first unfoamed thermoplastic resin sheet was formed in the same manner as in Example 4, except that thermoplastic resin composition 3 was used instead of thermoplastic resin composition 2.
A surface treatment agent (primer) and a film shown in Table 5 below were applied to the surface of the first unfoamed thermoplastic resin sheet of the obtained laminate on the side not in contact with the non-foamed thermoplastic resin sheet under the conditions shown in Table 5 below (drying temperature 130°C) to form a surface treatment layer.
The obtained laminate was heated at a temperature of 230°C, and the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet were expanded to form a first foamed thermoplastic resin layer (thickness 1098 μm), thereby obtaining a laminated foamed sheet.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

(Comparative Example 13)
A laminated foam sheet was obtained in the same manner as in Example 1, except that the thickness of the first foamed thermoplastic resin layer was adjusted to about 280 μm.
(Preparation of laminated molded body)
A laminated molded article was produced in the same manner as in Example 1, except that the laminated foamed sheet obtained above was used.

In the examples and comparative examples, various physical properties were measured and evaluated as described above, and the results are shown in Tables 4 and 5.

As can be seen from Table 4, in the examples, the laminated foam sheet had a suede-like appearance. In addition, the 0.1 mm compression hardness was 20 or less, and the elasticity (cushioning properties) was good. In addition, in the taper abrasion test, the number of rotations was 200 or more, and the abrasion resistance was high.

On the other hand, as can be seen from Table 5, in the cases of Comparative Examples 1 and 2, which did not have a foam layer and had an arithmetic mean height Sa of the surface treatment layer side of less than 5 μm, and Comparative Example 6, which did not use thermally expandable microcapsules as a foaming agent, it was not possible to develop a suede-like appearance. In the case of Comparative Example 3, in which a surface treatment layer was not disposed on the surface of the foam layer, it was also not possible to develop a suede-like appearance.
In the cases of Comparative Examples 4 and 5, in which the thickness of the surface treatment layer was less than 8.0 μm, the abrasion resistance was poor.
In the cases of Comparative Examples 7 and 8 in which thermally expandable microcapsules were added to the surface treatment layer, the microcapsules peeled off during foaming, failing to achieve a suede-like appearance, and the abrasion resistance was poor.
In Comparative Examples 11 and 12, the gloss was high, and whitening due to foamed thermally expandable microcapsules was suppressed, so that a suede-like appearance could not be achieved.
In the case of Comparative Example 13 in which the thickness of the foam layer was less than 300 μm, the 0.1 mm compression hardness was 28 N, and the elasticity (cushioning properties) was poor.

Claims (19)

The thermoplastic resin layer and the surface treatment layer are included.
the thermoplastic resin layer comprises a first foamed thermoplastic resin layer comprising a thermoplastic resin and expanded thermally expandable microcapsules;
In the first foamed thermoplastic resin layer, the thermoplastic resin includes at least one selected from the group consisting of an olefin-based thermoplastic elastomer and a polyolefin-based resin,
The surface treatment layer is formed of a coating film of a urethane paint,
the surface treatment layer is disposed on a first surface of the first foamed thermoplastic resin layer;
The thickness of the first foamed thermoplastic resin layer is 300 μm or more and 2000 μm or less,
The thickness of the surface treatment layer is 8.0 μm or more and 25 μm or less,
The laminated foam sheet has an arithmetic mean height Sa of the surface treatment layer side defined by ISO 25178 of 5 μm or more and 30 μm or less. The laminated foam sheet according to claim 1, wherein the first foamed thermoplastic resin layer contains 1 to 15 parts by weight of thermally expandable microcapsules per 100 parts by weight of thermoplastic resin. The laminated foam sheet according to claim 1 or 2, wherein the average bubble diameter of the expanded thermally expandable microcapsules is 30 μm or more and 200 μm or less. The laminated foam sheet according to any one of claims 1 to 3 , wherein the thermoplastic resin layer further comprises a non-foamed thermoplastic resin layer. The laminated foam sheet according to claim 4 , wherein the non-foamed thermoplastic resin layer contains one or more thermoplastic resins selected from the group consisting of olefin-based thermoplastic elastomers and polyolefin-based resins. The laminated foam sheet according to any one of claims 1 to 5 , further comprising a cushion layer disposed on the opposite side to the side on which the surface treatment layer of the thermoplastic resin layer is disposed. The laminated foam sheet according to any one of claims 1 to 6 , wherein the laminated foam sheet has a 25% compression hardness of 100 N or less, measured with the surface treatment layer as a load surface. The laminated foam sheet according to any one of claims 1 to 7 , wherein the cross-sectional porosity of the thermoplastic resin layer is 5% or more and 65% or less. The laminated foam sheet according to any one of claims 1 to 8 , wherein the laminated foam sheet has a rotation number of 200 or more in a Taber abrasion test (abrasion wheel CS-10, load 4.9 N) in accordance with JIS K 7204:1999. A laminated molded article obtained by molding the laminated foam sheet according to any one of claims 1 to 9 into a predetermined shape. The laminated molded body according to claim 10, wherein the laminated molded body is a skin material for a vehicle interior material. A method for producing the laminated foam sheet according to any one of claims 1 to 9 ,
A step of forming a first unfoamed thermoplastic resin sheet by sheet-molding a thermoplastic resin composition containing a thermoplastic resin and thermally expandable microcapsules at a temperature equal to or higher than the melting point of the thermoplastic resin and lower than the expansion start temperature of the thermally expandable microcapsules;
A step of applying a surface treatment agent to one surface of the first unfoamed thermoplastic resin sheet to form a surface treatment layer; and
The method includes a step of heating the obtained laminate at a temperature equal to or higher than the expansion initiation temperature of the thermally expandable microcapsules to expand the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet to form a first foamed thermoplastic resin layer ,
The thermoplastic resin includes at least one selected from the group consisting of an olefin-based thermoplastic elastomer and a polyolefin-based resin,
The method for producing a laminated foam sheet, wherein the surface treatment agent is a urethane paint . The method for producing a laminated foam sheet according to claim 12 , wherein the thermally expandable microcapsules have an expansion start temperature of 185°C or more and 215°C or less and a maximum foaming temperature of 190°C or more and 240°C or less. The method for producing a laminated foam sheet according to claim 12 or 13 , wherein the surface treatment agent is an aqueous polyurethane dispersion. The method for producing a laminated foam sheet according to any one of claims 12 to 14, wherein the coating film of the surface treatment agent has a tensile stress of 3 MPa or more, a tensile elongation of 30% or more, and a peel strength of 2 N/mm or more at a sample width of 15 mm in a 180° peel test, measured under conditions of 23 °C, 65 % RH, and a tensile speed of 500 mm/min. A method for producing the laminated molded body according to claim 10 or 11 ,
A step of forming a first unfoamed thermoplastic resin sheet by sheet-molding a thermoplastic resin composition containing a thermoplastic resin and thermally expandable microcapsules at a temperature equal to or higher than the melting point of the thermoplastic resin and lower than the expansion start temperature of the thermally expandable microcapsules; and
A step of applying a surface treatment agent to one surface of the first unfoamed thermoplastic resin sheet to form a surface treatment layer;
The obtained laminate is molded into a laminate molded product having a predetermined shape,
The thermoplastic resin includes at least one selected from the group consisting of an olefin-based thermoplastic elastomer and a polyolefin-based resin,
The surface treatment agent is a urethane paint,
A method for manufacturing a laminated molded body, in which, in a molding process of the laminated molded body, the laminated body is heated at a temperature equal to or higher than the expansion initiation temperature of the thermally expandable microcapsules, and the thermally expandable microcapsules in the first unfoamed thermoplastic resin sheet are expanded to form a first foamed thermoplastic resin layer. The method for producing a laminate molded product according to claim 16 , wherein the thermally expandable microcapsules have an expansion start temperature of 185°C or more and 215°C or less and a maximum foaming temperature of 190°C or more and 240°C or less. The method for producing a laminate molded product according to claim 16 or 17 , wherein the surface treatment agent is an aqueous polyurethane dispersion. The method for producing a laminate molded product according to any one of claims 16 to 18, wherein the coating film of the surface treatment agent has a tensile stress of 3 MPa or more and a tensile elongation of 30% or more, as measured in a tensile test carried out under conditions of an environment of 23°C and 65% RH at a tensile speed of 500 mm/min, and a peel strength of 2 N/mm or more at a sample width of 15 mm in a 180° peel test.