Recycling method and manufacturing method for laminated sheet for vehicle interior material

Abstract

To provide a recycling method of a vehicle interior material laminated sheet.SOLUTION: A recycling method of a vehicle interior material laminated sheet comprises: a step of heating a waste material of the laminated sheet; a crushing step of crushing the heated waste material of the laminated sheet by an impact crusher; a separation step of separating the waste material of the crushed material by wind separation into a recycled material being the crushed matter of a thermoplastic resin surface material and a foreign matter including the crushed matter of cross-linked resin foam; and a sheet molding step of melting, kneading, and molding a recycled resin composition including the recycled material subjected to the separation step to obtain a recycled sheet. In the heating step, the waste material of the laminated sheet is heated to a temperature higher than a melting point lowermost in the thermoplastic resin surface material by 25°C or more. In the crushing step, a requirement is satisfied, the requirement that a relational coefficient expressed by the following mathematical equation (1) of a rotation number R (rpm) of the impact crusher and a sieve opening S (m) of a screen is 0.500 rpm m2 or more and 2.650 rpm m2 or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for recycling a laminate sheet for vehicle interior materials, which comprises recycling a laminate sheet for vehicle interior materials containing a thermoplastic resin skin material and a crosslinked resin foam, and obtaining a pulverized product of the thermoplastic resin skin layer as a recycled material, and a method for producing a laminate sheet for vehicle interior materials using the recycled material. [Background technology]

[0002] Laminated sheets made by laminating a thermoplastic resin skin material and a crosslinked resin foam are widely used for vehicle interior materials such as automobile interior materials, particularly insmelt panels and door panels, because of their good heat resistance, moldability, and cushioning. However, crosslinked resin foam is less likely to melt than thermoplastic resin skin materials, and the crosslinked parts of the crosslinked resin foam become foreign matter, making it difficult to use the laminated sheet as a recycled material as it is. In addition, such laminated sheets usually contain a surface treatment agent layer, and when the laminated sheet is used as a recycled material as it is, the surface treatment agent also becomes foreign matter, and an abnormal appearance may occur.

[0003] As a method for recycling products containing synthetic resin, Patent Document 1 describes a method for crushing a synthetic resin laminate to separate and separate a synthetic resin skin material and a synthetic resin cushioning material. Patent Document 2 describes a method for separating and separating the amorphous polyethylene terephthalate and the rigid polyurethane foam from an integrated insulation body made of a molded product composed of amorphous polyethylene terephthalate and rigid polyurethane foam by leaving it in a high-temperature atmosphere below the melting point and then performing a heat treatment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-167832 A [Patent Document 2] Japanese Patent Application Publication No. 9-248869 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the methods described in Patent Documents 1 and 2 are used to recycle a laminate sheet containing a thermoplastic resin skin material and a cross-linked resin foam used as a vehicle interior material, there is a problem that the thermoplastic resin and the cross-linked resin foam are not sufficiently separated.

[0006] The present invention provides a method for recycling a laminate sheet for vehicle interior materials, and a method for producing a laminate sheet for vehicle interior materials, which can remove cross-linked foamed resin from a laminate sheet containing a thermoplastic resin skin material and a cross-linked resin foam used as a vehicle interior material, efficiently recover the thermoplastic resin as a recyclable material, and reuse it as a thermoplastic resin skin material for the laminate sheet for vehicle interior materials. [Means for solving the problem]

[0007] The present invention relates to a method for recycling a laminate sheet for vehicle interior materials, which includes a thermoplastic resin skin material and a crosslinked resin foam disposed on a first surface of the thermoplastic resin skin material, the method comprising the steps of: heating a waste laminate sheet; crushing the heated laminate sheet waste with an impact crusher; separating the crushed laminate sheet waste by air separation into a recycled material, which is a crushed thermoplastic resin skin material, and a foreign matter including a crushed crosslinked resin foam; and a sheet molding step of melting and kneading a recycled resin composition containing the recycled material obtained through the separation step, and molding the recycled sheet, wherein in the heating step, the laminate sheet waste is heated to a temperature 25° C. or higher than the lowest melting point Tmin of the thermoplastic resin skin material, and in the crushing step, a relationship coefficient between the rotation speed R (rpm) of the impact crusher and the mesh opening S (m) of a screen, which is expressed by the following mathematical formula (1), is 0.500 rpm·m 2 More than 2.650rpm m 2 The present invention relates to a method for recycling a laminate sheet for vehicle interior materials, which satisfies the following conditions:

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[0008] The present invention also relates to a method for producing a laminate sheet for vehicle interior materials, characterized in that a recycled sheet obtained by the above-mentioned method for recycling vehicle interior materials is used. Effect of the Invention

[0009] According to the method for recycling a laminate sheet for vehicle interior materials of the present invention, the cross-linked foamed resin component can be effectively removed from a laminate sheet containing a thermoplastic resin skin material and a cross-linked resin foam, and the thermoplastic resin component can be efficiently recovered as a recycled material and reused as the thermoplastic resin skin material of the laminate sheet for vehicle interior materials. Furthermore, according to the method for producing a laminate sheet for vehicle interior materials of the present invention, it is possible to provide a laminate sheet for vehicle interior materials using a thermoplastic resin component recovered as a recycled material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, they found that by heating a waste laminate sheet containing a thermoplastic resin skin material and a crosslinked resin foam disposed on a first surface of the thermoplastic resin skin material at a predetermined temperature, pulverizing the waste laminate sheet using an impact pulverizer under conditions where the relationship coefficient between the rotation speed R (rpm) and the screen opening S (m) satisfies a predetermined range, and then sorting the pulverized waste laminate sheet using air separation, it is possible to effectively remove foreign matter such as crosslinked foamed resin components and efficiently recover the thermoplastic resin components as recycled materials.

[0011] (Recycling method for laminated sheets for vehicle interior materials) First, in a heating step, a scrap of laminated sheet for vehicle interior materials, which includes a thermoplastic resin skin material and a cross-linked resin foam, is heated. In the laminated sheet, a cross-linked resin foam (cross-linked resin foam layer) is laminated on a first surface of a thermoplastic resin skin material (thermoplastic resin skin layer). In the heating step, the scrap of the laminated sheet is heated to a temperature 25°C higher than the lowest melting point Tmin of the thermoplastic resin skin material, that is, to a temperature of "Tmin+25°C" or higher. This softens the thermoplastic resin skin material, and the scrap of the laminated sheet is then crushed and separated by air force, so that the crushed thermoplastic resin skin material can be easily separated from the crushed cross-linked resin foam. The heating temperature is preferably [Tmin+30°C] or higher, more preferably [Tmin+35°C] or higher, and particularly preferably [Tmin+40°C] or higher. The upper limit of the heating temperature is not particularly limited as long as it is below the temperature at which the thermoplastic resin decomposes. For example, from the viewpoints of resin deterioration and processability, the temperature may be 250°C or lower, or may be 200°C or lower.

[0012] The lowest melting point Tmin of a thermoplastic resin skin material can be confirmed by performing differential scanning calorimetry (DSC) using a waste material of a thermoplastic resin skin material or a laminate sheet. Specifically, the lowest melting point Tmin of a thermoplastic resin skin material can be confirmed by determining the value of the minimum melting peak in the DSC curve obtained by heating 8 mg (5 to 15 mg) of skin material or 8 mg (5 to 15 mg) of waste material of a laminate sheet at a heating rate of 10 ° C. / min from 40 ° C. to 200 ° C. (first heating) to melt it, then cooling down from 200 ° C. to 40 ° C. at a heating rate of 10 ° C. / min to crystallize it, and then heating up from 40 ° C. to 200 ° C. (second heating) at a heating rate of 10 ° C. / min to obtain all DSC curves (first heating → cooling → second heating) obtained by heating up from 40 ° C. to 200 ° C. at a heating rate of 10 ° C. / min (second heating).

[0013] In the heating step, the heating time is not particularly limited, but may be, for example, from the viewpoint of suppressing resin deterioration and processability, from 10 seconds to 5 minutes, or from 20 seconds to 3 minutes.

[0014] The thermoplastic resin constituting the thermoplastic resin skin material is not particularly limited, and examples thereof include polyolefin-based resins, vinyl chloride-based resins, and olefin-based thermoplastic elastomers. From the viewpoint of excellent separability from crosslinked resin foam and suitable use as a recyclable material in the skin layer of a laminate sheet for vehicle interior materials, the thermoplastic resin skin material preferably contains one or more selected from the group consisting of olefin-based thermoplastic elastomers and polyolefin-based resins. From the viewpoint of excellent rubber elasticity at high temperatures and during long-term deformation and high heat resistance, the thermoplastic resin skin material more preferably contains an olefin-based thermoplastic elastomer, and further preferably contains an olefin-based thermoplastic elastomer and a polyolefin-based resin. When the thermoplastic resin skin material contains one or more selected from the group consisting of olefin-based thermoplastic elastomers and polyolefin-based resins, the heating temperature is preferably 135°C or more and 250°C or less, more preferably 140°C or more and 230°C or less, and particularly preferably 150°C or more and 195°C or less.

[0015] 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 polymerization type and a dynamic crosslinking type in combination.

[0016] 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 the 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 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 kinds.

[0017] The crosslinked resin foam is not particularly limited, but is preferably a crosslinked polyolefin resin foam from the viewpoint of excellent separability from a thermoplastic resin skin material. 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 it. The polyolefin resin may be any of those described above.

[0018] The thermoplastic resin skin material and the crosslinked resin foam may be directly bonded by heating the surfaces to be bonded to a surface temperature of 120° C. to 200° C., or may be bonded via an adhesive. When the thermoplastic resin skin material contains one or more selected from the group consisting of an olefin-based thermoplastic elastomer and a polyolefin-based resin, and the crosslinked resin foam is formed of a crosslinked polyolefin-based resin foam, they can be directly bonded.

[0019] The laminated sheet may further include a surface treatment agent layer. The surface treatment agent constituting the surface treatment agent layer is not particularly limited, and may be, for example, a water-based urethane paint, a solvent-based urethane paint, or the like, and may also be silicon, silicon beads, or urethane beads. When the thermoplastic resin skin material contains one or more selected from the group consisting of an olefin-based thermoplastic elastomer and a polyolefin-based resin, the surface treatment agent layer is often included from the viewpoint of scratch resistance, abrasion resistance, or the like. The surface treatment agent layer may be disposed on a second surface opposite to the first surface of the thermoplastic resin skin material, and may be bonded to the thermoplastic resin skin material via a primer. According to the recycling method of the present invention, the surface treatment agent layer can be effectively removed from the thermoplastic resin skin material.

[0020] The scrap laminate sheet may be waste material from the production of vehicle interior materials, or may be material recovered from used vehicle interior materials. The scrap laminate sheet may be cut into a size of 5 cm to 30 cm using a cutting machine or a punching machine as necessary. Here, the size of the scrap laminate sheet means the maximum length of the scrap laminate sheet.

[0021] Next, in the crushing step, the heated laminated sheet waste material is crushed by an impact crusher. In the crushing step, the relationship coefficient between the rotation speed R (rpm) of the impact crusher and the screen opening S (m) expressed by the following formula (1) is 0.500 rpm m 2 More than 2.650rpm m 2 The following range is satisfied. In the following description, the units of the relationship coefficients will be omitted.

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[0022] The coefficient of relationship affects the crushing ability (processability) and the quality of the recycled material. When the coefficient of relationship is less than 0.500, the separation of the thermoplastic resin skin material from foreign matter other than the thermoplastic resin skin material, such as the crosslinked resin foam and the surface treatment agent layer, becomes insufficient, and the quality of the recycled material becomes poor. In addition, the screen passability of the crushed material decreases, and the crushing ability decreases significantly. On the other hand, when the coefficient of relationship is more than 2.650, the separation of the thermoplastic resin skin material as the recycled material from foreign matter other than the thermoplastic resin skin material, such as the crosslinked resin foam and the surface treatment agent layer, becomes insufficient, and the quality of the recycled material becomes poor. The coefficient of relationship is preferably 0.550 or more and 2.500 or less, and more preferably 0.550 or more and 2.000 or less.

[0023] The impact crusher is not particularly limited as long as it can crush the object by impact. For example, a crusher that rotates a rotor at high speed to obtain an impact force and crushes the object with a hammer (rotary blade) attached to the rotor can be used. The impact crusher is preferably a swing hammer crusher type from the viewpoint of efficiently crushing the laminated sheet waste material with a large impact force and separating the crosslinked resin foam and the surface treatment agent.

[0024] It is preferable to crush the waste laminated sheet into pieces having a size of 1 mm to 80 mm, and more preferably 3 mm to 40 mm. Here, the size of the crushed pieces means the maximum length of the crushed pieces. If the size of the crushed pieces is within the above-mentioned range, foreign matter such as the crosslinked resin foam and the surface treatment agent layer is easily peeled off from the thermoplastic resin skin material. The size of the crushed pieces can be adjusted by the size of the screen openings of the impact crusher, etc.

[0025] The size of the openings in the screen of the impact crusher is preferably 0.015 m or more and 0.030 m or less, and more preferably 0.015 m or more and 0.025 m or less, from the viewpoint of easily crushing the waste laminated sheet to the above-mentioned size within a range that satisfies the above-mentioned relationship coefficient. The shape of the openings in the screen is not particularly limited, and may be circular, elliptical, rectangular, or other shapes. Here, the size of the openings in the screen means the diameter when the opening shape is circular, and means the maximum length when the opening shape is other than circular.

[0026] The rotation speed of the impact crusher is not particularly limited as long as it satisfies the above-mentioned relationship coefficient. From the viewpoint of efficiently peeling off and crushing foreign matter such as the crosslinked resin foam and the surface treatment agent layer from the thermoplastic resin skin material, for example, the rotation speed may be 2500 rpm or more and 4500 rpm or less, or may be 2500 rpm or more and 4000 rpm or less.

[0027] Next, in a separation step, the crushed laminate sheet waste is separated by wind separation into recycled material, which is crushed thermoplastic resin skin material, and foreign matter including crushed crosslinked resin foam, and the recycled material is recovered. Wind separation is not particularly limited, and can be carried out, for example, using a wind separator (also called a wind classifier). The air volume of the blower that transports the crushed laminate sheet waste to the wind separator is not particularly limited, and can be, for example, 5 m 3 / min or more 100m 3 The wind speed of the pneumatic separator is not particularly limited, but may be, for example, 5 m / sec or more and 30 m / sec or less.

[0028] In the separation step, it is preferable to sieve the recycled material recovered after the wind separation using a vibrating screen to further remove foreign matter such as crushed crosslinked resin foam adhering to the surface of the recycled material. The opening of the vibrating screen is preferably the same as the opening of the screen of the impact crusher, for example.

[0029] The air sorting machine may be equipped with an air separator and a vibrating screen, so that air separation and sieve sorting can be performed.

[0030] From the viewpoint of recyclability and the surface smoothness of the recycled sheet, the recycled material preferably has a residual foreign matter rate of 0.10% by weight or less, more preferably 0.090% by weight or less, even more preferably 0.080% by weight or less, even more preferably 0.070% by weight or less, and particularly preferably 0.060% by weight or less. The lower limit of the residual foreign matter rate of the recycled material is better as it is closer to 0% by weight, and may be, for example, 0.001% by weight or more.

[0031] From the viewpoint of recyclability and the surface beauty of the recycled sheet, the recycled material preferably has a foreign matter adhesion number rate of 8.0% or less, more preferably 7.0% or less, even more preferably 6.0% or less, and particularly preferably 5.0% or less. The closer to 0% the foreign matter adhesion number rate of the recycled material is, the better, and may be, for example, 0.010% or more.

[0032] The residual foreign matter rate and the rate of foreign matter particles attached to the recycled material can be measured as follows. (1) Approximately 100g of recycled material is randomly collected as a sample, and the weight of the sample is accurately measured to three decimal places using an electronic balance and designated as W0. The total number of crushed pieces contained in the sample is also measured and designated as N0. If the weight of the recycled material is less than 100g, all of the recycled material is used as the sample. (2) Observe the appearance of each crushed particle in the sample and select any crushed particles that have foreign matter attached. (3) Measure the number of crushed pieces with the selected foreign matter attached and call it N1. (4) Any foreign matter adhering to the crushed material is removed with a file, and the weight of the sample after the foreign matter has been removed is measured accurately to three decimal places on an electronic balance and recorded as W1. (5) Calculate the residual foreign matter rate of the recycled material using the following formula (2). Remaining foreign matter rate of recycled material (weight%) = (W0-W1) / W0×100 (2) (6) Calculate the rate of foreign matter adhesion in recycled materials using the following formula (3). Rate of foreign matter adhesion in recycled materials (%) = N1 / N0 x 100 (3)

[0033] From the viewpoint of the surface smoothness and surface beauty of the recycled sheet, the recycled material preferably has a foreign matter remaining coating thickness of 25 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less.

[0034] Next, in the sheet forming process, the recycled resin composition containing the recycled material obtained through the separation process is melted and kneaded, and formed to obtain a recycled sheet. From the viewpoint of recyclability and physical properties of the recycled sheet, the recycled resin composition preferably contains 1% by weight or more and 60% by weight or less of the recycled material, and 40% by weight or more and 99% by weight or less of unused (virgin) thermoplastic resin having the same composition as the recycled material, more preferably contains 5% by weight or more and 60% by weight or less of the recycled material, and 40% by weight or more and 95% by weight or less of unused (virgin) thermoplastic resin having the same composition as the recycled material, further preferably contains 20% by weight or more and 60% by weight or less of the recycled material, and 40% by weight or more and 80% by weight or less of unused (virgin) thermoplastic resin having the same composition as the recycled material, and particularly preferably contains 30% by weight or more and 60% by weight or less of the recycled material, and 40% by weight or more and 70% by weight or less of unused (virgin) thermoplastic resin having the same composition as the recycled material.

[0035] The recycled resin composition may contain, as necessary, one or more additives such as softeners, inorganic fillers, antioxidants, light stabilizers, UV absorbers, antistatic agents, lubricants, and colorants, etc. The content of the additives may be, for example, 0.1% by weight or less.

[0036] The sheet molding is not particularly limited, and may be calendar molding or extrusion molding. The thickness of the recycled sheet is not particularly limited, and may be appropriately set as necessary. The thickness of the recycled sheet may be, for example, 300 μm or more and 1500 μm or less.

[0037] (Method of manufacturing laminated sheet for vehicle interior materials) The laminate sheet for vehicle interior materials can be produced by the same method as known methods, except that a recycled sheet obtained by the above-mentioned method for recycling vehicle interior materials is used. A laminate sheet for vehicle interior materials can be obtained by laminating a recycled sheet obtained by calendar molding or extrusion molding on the surface of a crosslinked resin foam (crosslinked resin foam layer) by a method of thermal lamination to form a thermoplastic resin skin layer. Alternatively, a laminate sheet for vehicle interior materials can be obtained by bonding a recycled sheet obtained by calendar molding or extrusion molding to the surface of a crosslinked resin foam (crosslinked resin foam layer) using an adhesive such as a two-component curing adhesive. A laminate sheet for vehicle interior materials may be obtained by a method (calendar topping method) in which a recycled resin composition containing a molten recycled material rolled by a calendar roll or a recycled material and an unused (virgin) thermoplastic resin having the same composition as the recycled material is topped on the surface of a crosslinked resin foam to form a recycled sheet (thermoplastic resin skin layer). Alternatively, a laminate sheet for vehicle interior materials may be obtained by extruding a molten recycled material or a recycled resin composition containing a molten recycled material and an unused (virgin) thermoplastic resin having the same composition as the recycled material from a T-die of an extruder onto the surface of a crosslinked resin foam to form a recycled sheet (thermoplastic resin skin layer).

[0038] From the viewpoints of excellent rubber elasticity during long-term deformation at high temperatures and high heat resistance, the recycled sheet is preferably made of a recycled material derived from a thermoplastic resin skin material containing an olefin-based thermoplastic elastomer, and more preferably made of a recycled material derived from a thermoplastic resin skin material containing an olefin-based thermoplastic elastomer and a polyolefin-based resin. Examples of the olefin-based thermoplastic elastomer and the polyolefin-based resin include those mentioned above.

[0039] The crosslinked resin foam is not particularly limited, but is preferably a crosslinked polyolefin resin foam. The crosslinked polyolefin resin foam is not particularly limited, and can be obtained by crosslinking a polyolefin resin by a conventionally known method and then foaming. As the polyolefin resin, the above-mentioned ones can be appropriately used. The method for forming a 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, normal pressure foaming, and chemical reaction foaming. As the foaming agent, inorganic gas, hydrocarbon or halogenated hydrocarbon having a boiling point of -50 to 120°C, water, a thermal decomposition type foaming agent, etc. can be used.

[0040] The crosslinked resin foam is not particularly limited, and may have a crosslinking degree of 30% to 65%, or 40% to 55%, from the viewpoint of moldability. The crosslinking degree 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.

[0041] The crosslinked resin foam is not particularly limited, but may have an expansion ratio of 10 to 40 from the viewpoint of flexibility and cushioning. The expansion ratio of the crosslinked resin foam is, for example, the specific volume (unit cm) of the expandable resin sheet before foaming and the crosslinked resin foam sheet. 3 The specific volume of the crosslinked resin foam sheet / specific volume of the expandable resin sheet before foaming can be calculated by measuring the specific volume of the crosslinked resin foam sheet / specific volume of the expandable resin sheet before foaming.

[0042] The crosslinked resin foam may contain additives such as a foaming assistant, a softener, a lubricant, an antioxidant, an antistatic agent, a flame retardant, an ultraviolet absorber, a light stabilizer, a colorant, and an inorganic filler, as necessary.

[0043] The laminated sheet for vehicle interior materials may further include a surface treatment agent layer. The surface treatment agent constituting the surface treatment agent layer is not particularly limited, and examples thereof include water-based urethane paint and solvent-based urethane paint. When the thermoplastic resin skin layer includes one or more selected from the group consisting of olefin-based thermoplastic elastomers and polyolefin-based resins, it is preferable to include a surface treatment agent layer from the viewpoint of scratch resistance, abrasion resistance, and the like. The surface treatment agent layer may be disposed on a second surface of the thermoplastic resin skin material opposite to the first surface on which the crosslinked resin foam is disposed, and may be bonded to the thermoplastic resin skin material via a primer. This improves the scratch resistance and abrasion resistance of the thermoplastic resin skin material.

[0044] The laminate sheet for vehicle interior materials is not particularly limited, but can be suitably used as vehicle interior materials such as instrument panels, door trims, trunk trims, seats, pillar covers, ceiling materials, rear trays, console boxes, airbag covers, arm rests, head rests, meter covers, and crash pads for vehicles such as automobiles. EXAMPLES

[0045] The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples.

[0046] (Laminated sheet waste) Skin material: 40% by weight of dynamically crosslinked olefin-based thermoplastic elastomer (Milastomer (registered trademark) "8030NHS" manufactured by Mitsui Chemicals, Inc.), 50% by weight of polymerization type olefin-based thermoplastic elastomer ("R-110E" manufactured by Prime Polymer Co., Ltd.), 10% by mass of random polypropylene ("B-221WA" manufactured by Prime Polymer Co., Ltd.), 0.65 parts by weight of additives, lubricant, antioxidant and UV absorber per 100 parts by weight of resin in total, thickness 500 μm Cross-linked resin foam: Cross-linked polyolefin resin foam (Toray Industries, Inc. "JP17-15025"), cross-linking degree: 43%, expansion ratio: 15 times, thickness: 2.5 mm) Surface treatment layer: urethane paint (Dainichiseika Color & Chemicals "Lezaroid LU-855SP"), thickness 6μm In the laminated sheet, a crosslinked resin foam is laminated on one surface of the skin material and directly bonded to the skin material, and a surface treatment agent layer is laminated and bonded to the other surface of the skin material via a one-liquid primer ("Lezaroid LU-236" manufactured by Dainichi Seikagaku Kogyo Co., Ltd.) The laminated sheet was trimmed to be used as an automobile door trim, and the remaining waste material was collected.

[0047] The Tmin of the above skin material was confirmed using a differential scanning calorimeter (Shimadzu Corporation, "DSC-60Plus") to determine the minimum melting peak value in the DSC curve obtained by heating 8 g of the skin material from 40°C to 200°C at a heating rate of 10°C / min (first heating) to melt it, then cooling from 200°C to 40°C at a heating rate of 10°C / min to crystallize it, and then heating it further from 40°C to 200°C at a heating rate of 10°C / min (second heating) to obtain a DSC curve. The Tmin was determined to be 110.6°C.

[0048] Example 1 Cut the laminated sheet scraps into pieces of about 5 cm square (about 25 cm 2), heated to 140°C with an infrared heater, and left at 140°C for 5 seconds, after which it was impact crushed using an impact crusher (Makino Sangyo Co., Ltd., Sling Hammer Crusher, Model "HC-20") under the conditions of rotation speed and screen opening size shown in Table 1 below. In the impact crusher, the shape of the screen openings was circular. The rotation speed of the impact crusher was determined by the current value. After that, a DF type fan (DF-1: 0.75KW, 2P, air volume: 6.5m) manufactured by Horai Co., Ltd. 3 The crushed material was fed into a Horai AS separator (pre-air separator, main separator, vibrating screen) at a wind speed of 10-15 m / s to separate the recycled material from the crosslinked resin foam and surface treatment agent layer, and the recycled material was collected. In the AS separator, the openings in the vibrating screen were circular and had a size (diameter) of 30 mm. 50 g of the recycled material was melt-kneaded at 180°C for 5 minutes in a test roll to produce a recycled sheet with a thickness of approximately 500 μm.

[0049] (Examples 2 to 4) Recycled materials were collected and recycled sheets were produced in the same manner as in Example 1, except that the cut size of the scrap laminated sheet, the heating temperature, and the impact crushing conditions were as shown in Table 1 below.

[0050] (Examples 5 to 7) An impact crusher manufactured by Onoue Machinery Co., Ltd. (Sling Hammer Crusher, model "WALD-15") was used to recover recycled materials and produce recycled sheets in the same manner as in Example 1, except that the cut size of the laminated sheet waste material and the heating and impact crushing conditions were as shown in Table 1 below.

[0051] Comparative Example 1 The recycled material was recovered and a recycled sheet was produced in the same manner as in Example 1, except that the cut waste laminated sheet was crushed in an impact crusher without being heated.

[0052] Comparative Example 2 Scrap laminated sheet material, about 15cm square (about 225cm 2 ) and the cut laminated sheet waste was not heated and was crushed under the impact crushing conditions shown in Table 2 below. The same procedures as in Example 1 were repeated to recover the recycled material and produce a recycled sheet.

[0053] (Comparative Examples 3 to 5) The recycled materials were recovered and recycled sheets were produced in the same manner as in Example 1, except that the heating temperature was set as shown in Table 2 below.

[0054] (Comparative Examples 6 and 7) Recycled materials were collected and recycled sheets were produced in the same manner as in Example 1, except that the cut size of the scrap laminated sheet, the heating temperature, and the impact crushing conditions were as shown in Table 2 below.

[0055] Comparative Example 8 The cut size of the scrap laminate sheet and the impact crushing conditions were as shown in Table 2 below, and the recycled material was recovered and a recycled sheet was produced in the same manner as in Example 1, except that air separation was not performed. The recycled material contained crushed crosslinked resin foam.

[0056] Comparative Example 9 Scrap laminated sheet material, about 15cm square (about 225cm 2 ), heated to 160°C with an infrared heater, and left at 160°C for 5 seconds, after which it was shear-pulverized using a shear crusher (HORAI Corporation, "BO-480") under the conditions of the rotation speed and screen opening size shown in Table 1 below. In the shear crusher, the shape of the screen openings was circular. The rotation speed of the shear crusher was determined by the current value. Thereafter, in the same manner as in Example 1, the recycled material was separated from the crosslinked resin foam and the surface treatment agent layer by air force, the recycled material was recovered, and a recycled sheet was produced.

[0057] In Examples 1 to 7 and Comparative Examples 1 to 7 and 9, the correlation coefficient between the rotation speed R (rpm) of the pulverizer and the screen opening S (m) shown in the following formula 1 was calculated, and the results are shown in Tables 1 and 2 below.

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[0058] In Examples 1 to 7 and Comparative Examples 1 to 7 and 9, the foreign matter remaining rate and the rate of number of foreign matter attachments in the recycled materials were measured as described below. The thickness of the coating film with remaining foreign matter in the recycled materials was also observed and evaluated as described below. The results are shown in Tables 1 and 2 below. The appearance of the recycled sheets was also observed and evaluated as described below, and the results are shown in Tables 1 and 2 below.

[0059] (Foreign matter remaining rate and rate of foreign matter adhesion) (1) Approximately 100 g of recycled material was randomly collected as a sample, and the weight of the sample was accurately measured to three decimal places using an electronic balance and designated as W0. In addition, the total number of crushed pieces contained in the sample was measured and designated as N0. (2) The appearance of each crushed piece in the sample was observed, and crushed pieces with foreign matter attached were selected. (3) The number of crushed pieces with the selected foreign matter attached was counted and designated as N1. (4) Any foreign matter adhering to the crushed material was removed with a file, and the weight of the sample after the foreign matter was removed was measured accurately to three decimal places on an electronic balance and recorded as W1. (5) The residual foreign matter rate of the recycled materials was calculated using the following formula (2). Remaining foreign matter rate of recycled material (weight%) = (W0-W1) / W0×100 (2) (6) The rate of foreign matter adhesion in recycled materials was calculated using the following formula (3). Rate of foreign matter adhesion in recycled materials (%) = N1 / N0 x 100 (3)

[0060] (Foreign matter remaining coating thickness) The crushed material with foreign matter attached that was selected when measuring the foreign matter remaining rate and the foreign matter adhesion rate was cut perpendicular to the foreign matter with a sharp blade, and the cross section with the foreign matter attached was measured using a One Shot VR-5000 manufactured by Keyence Corporation. Observation was performed at 300x magnification (detection limit: 0.01 μm) to detect foreign matter adhering to the surface of the recycled material, and the thickness of the coating film with remaining foreign matter was confirmed using the scale measurement system built into the device.

[0061] (Appearance of the recycled sheet) The surface of the recycled sheet was observed at 20 times magnification with a magnifying glass, and the appearance was evaluated according to the following 5-level scale. In the following, size refers to the maximum length of the convex and / or concave portions on the sheet surface. 1: The sheet surface is almost even with no irregularities. 2: The sheet surface has small irregularities (less than 1 mm in size) scattered throughout 3: The sheet surface has a small amount of obvious irregularities (over 1 mm in size) and the appearance is somewhat poor. 4: There are many obvious irregularities (over 1mm) on the sheet surface, and the appearance is poor. 5: The melted and mixed recycled material stuck to the test roll, making it impossible to form a sheet.

[0062] [Table 1]

[0063] [Table 2]

[0064] As can be seen from Table 1, in the examples, the cross-linked foamed resin component is effectively removed from the laminate sheet containing a thermoplastic resin skin material and a cross-linked resin foam, and the thermoplastic resin component is efficiently recovered as a recycled material and can be reused as a thermoplastic resin skin material for the laminate sheet for vehicle interior materials. On the other hand, as can be seen from Table 2, in Comparative Examples 1 to 5 in which the waste laminate sheet was not heated or the heating temperature was low, foreign matter containing the cross-linked foamed resin component could not be effectively removed from the laminate sheet, and the foreign matter remaining rate and / or the number of foreign matter attachments were high. In addition, in Comparative Example 6 in which the correlation coefficient was low or Comparative Example 7 in which the correlation coefficient was high, foreign matter containing the cross-linked foamed resin component could not be effectively removed from the laminate sheet, and the foreign matter remaining rate and / or the number of foreign matter attachments were high. In Comparative Example 8 in which air separation was not performed, the cross-linked foamed resin component could not be removed. In Comparative Example 9 in which shear crushing was performed instead of impact crushing, foreign matter containing the cross-linked foamed resin component could not be effectively removed from the laminate sheet, and the foreign matter remaining rate and the number of foreign matter attachments were high.

Claims

1. A method for recycling a laminate sheet for vehicle interior materials, comprising: a thermoplastic resin skin material; and a crosslinked resin foam disposed on a first surface of the thermoplastic resin skin material, the method comprising the steps of: heating the waste laminated sheet; a crushing step of crushing the heated waste laminated sheet using an impact crusher; A separation step of separating the crushed laminate sheet waste material into recycled material, which is crushed thermoplastic resin skin material, and foreign matter, which includes crushed crosslinked resin foam, by wind separation; A sheet molding step of melt-kneading and molding the recycled resin composition containing the recycled material obtained through the separation step to obtain a recycled sheet, In the heating step, the waste laminate sheet is heated to a temperature 25° C. or more higher than the lowest melting point Tmin of the thermoplastic resin skin material, In the crushing step, the coefficient of relationship between the rotation speed R (rpm) of the impact crusher and the screen opening S (m) expressed by the following formula (1) is 0.500 rpm m 2 More than 2.650rpm・m 2 A method for recycling a laminate sheet for vehicle interior materials, characterized in that the following conditions are satisfied: [0045]

2. 2. The method for recycling a laminate sheet for vehicle interior materials according to claim 1, wherein the laminate sheet includes a surface treatment agent layer, and in the separation step, the pulverized waste laminate sheet is separated by air separation into a recycled material which is a pulverized thermoplastic resin skin material and foreign matter which includes the crosslinked resin foam and pulverized material of the surface treatment agent layer.

3. 3. The method for recycling a laminate sheet for vehicle interior materials according to claim 1, wherein the recycled material has a residual foreign matter rate of 0.10% by weight or less and a rate of number of foreign matter particles attached thereto of 8.0% or less.

4. 4. The method for recycling a laminate sheet for vehicle interior materials according to claim 1, wherein the thickness of the coating film remaining on the recycled material is 25 μm or less.

5. 5. The method for recycling a laminate sheet for vehicle interior materials according to claim 1, wherein the thermoplastic resin skin material comprises at least one material selected from the group consisting of an olefin-based thermoplastic elastomer and a polyolefin-based resin.

6. 6. The method for recycling a laminate sheet for vehicle interior materials according to claim 1, wherein the crosslinked resin foam is formed of a crosslinked polyolefin-based resin foam.

7. The method for recycling a laminate sheet for vehicle interior materials according to any one of claims 1 to 6, wherein the recycled resin composition contains the recycled material in an amount of 1% by weight or more and 60% by weight or less, and an unused thermoplastic resin having the same composition as the recycled material in an amount of 40% by weight or more and 99% by weight or less.

8. A method for producing a laminated sheet for vehicle interior materials, comprising using a recycled sheet obtained by the method for recycling vehicle interior materials according to any one of claims 1 to 7.

9. The method for producing a laminate sheet for vehicle interior materials according to claim 8, further comprising forming a thermoplastic resin skin layer using the recycled sheet to obtain a laminate sheet comprising a surface treatment agent layer, a thermoplastic resin skin layer and a crosslinked resin foam.

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