JP5860637B2 - Multilayer structure and method for producing multilayer structure - Google Patents

Description

  The present invention relates to a multilayer structure using a thermoplastic resin, and more specifically, has a laminate in which a plurality of layers containing a thermoplastic resin are laminated, and at least one of the plurality of layers is a filler. And a method for producing the multilayer structure.

  Conventionally, various films containing a thermoplastic resin have been proposed and widely used in various applications.

  As an example of the film, Patent Documents 1 and 2 below disclose a thermoplastic resin film having a multilayer structure in which a plurality of layers containing a thermoplastic resin are laminated.

  FIG. 1 of Patent Document 1 shows a polyethylene resin layer E, a polyolefin adhesive resin layer D, a propylene resin layer C, a polyolefin adhesive resin layer B, a gas barrier resin A, a polyolefin adhesive resin layer B, a propylene resin layer C, and a polypropylene resin layer. A thermoplastic resin film in which F is laminated in this order is shown. Examples of the gas barrier resin A include saponified ethylene-vinyl acetate copolymers.

  Patent Document 2 below discloses a bubble-containing multilayer film having a layer having fine bubbles of three or more layers and a layer separating the layers, and these layers are alternately laminated in the thickness direction. Has been. The layer having fine bubbles includes a thermoplastic resin and a thermoplastic resin that is incompatible with the thermoplastic resin. Patent Document 2 describes that the surface layer of the microbubble-containing film may contain a thermoplastic resin and inorganic particles.

JP 2003-1771 A JP 2003-136619 A

  There exists a problem that the tensile strength of the thermoplastic resin film which has the conventional multilayer structure as described in the said patent documents 1 and 2 is low. Furthermore, the conventional thermoplastic resin film having a multilayer structure has a problem of low mechanical strength.

  An object of the present invention is to provide a multilayer structure having a high tensile strength and a method for producing the multilayer structure.

  According to a wide aspect of the present invention, the first layer containing a thermoplastic resin has a laminate in which five or more layers are laminated, and at least one of the plurality of first layers contains a filler. A multilayer structure is provided.

  In the multilayer structure according to the present invention, the filler material is preferably a carbon material having a graphene structure. The filler material is preferably a carbon nanotube. The aspect ratio of the filler is preferably more than 1. The filler is more preferably a rod-like filler or a plate-like filler. The average absolute value of the angles formed by the length directions of the fillers in the layer containing the filler is 30 ° or less with respect to the direction in which the length directions of all the fillers in the layer containing the filler are averaged. It is preferable.

  In another specific aspect of the multilayer structure according to the present invention, the multilayer structure includes a laminate in which ten or more first layers are laminated.

  In still another specific aspect of the multilayer structure according to the present invention, the average thickness of the first layer is 5 nm or more and 10 μm or less.

  In another specific aspect of the multilayer structure according to the present invention, the thickness of the laminate is 0.03 mm or more and 3 mm or less.

  In another specific aspect of the multilayer structure according to the present invention, the thermoplastic resin is a polycarbonate resin.

  In still another specific aspect of the multilayer structure according to the present invention, the multilayer structure has a second layer different from the first layer, and the one second layer is only on the first surface of the laminate. The two second layers are stacked one by one on the first surface of the stacked body and on the second surface opposite to the first surface.

  The second layer may also contain a filler in at least one layer, and the filler material is preferably a carbon material having a graphene structure. The filler material is preferably a carbon nanotube. The aspect ratio of the filler is preferably more than 1. The filler is more preferably a rod-like filler or a plate-like filler. The average absolute value of the angles formed by the length directions of the fillers in the layer containing the filler is 30 ° or less with respect to the direction in which the length directions of all the fillers in the layer containing the filler are averaged. It is preferable.

  In another specific aspect of the multilayer structure according to the present invention, the thickness of each of the second layers is 5 nm or more and 1000 μm or less.

  In another specific aspect of the multilayer structure according to the present invention, at least one of the plurality of first layers contains bubbles.

  In another specific aspect of the multilayer structure according to the present invention, the multilayer structure is obtained by stretching the laminate.

  In still another specific aspect of the multilayer structure according to the present invention, the laminate is obtained by a multilayer melt extrusion method.

  Moreover, the method for manufacturing a multilayer structure according to the present invention is a method for manufacturing the multilayer structure described above, in which five or more first layers including a thermoplastic resin are stacked, A step of forming a laminate in which at least one of the first layers contains a filler by a multilayer melt extrusion method.

  In a specific aspect of the method for producing a multilayer structure according to the present invention, the laminate is formed by a multi-manifold method or a feed block method.

  In another specific aspect of the method for producing a multilayer structure according to the present invention, one of the second layers is laminated only on the first surface of the laminate, or two of the second layers are A step of laminating one layer at a time on the first surface of the laminate and a second surface opposite to the first surface is further provided.

  Since the multilayer structure according to the present invention has a laminate in which five or more first layers containing a thermoplastic resin are laminated, and at least one of the plurality of first layers contains a filler. , Tensile strength can be increased.

FIG. 1 is a cross-sectional view schematically showing a multilayer structure according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a multilayer structure according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing a multilayer structure according to the third embodiment of the present invention. FIG. 4 is a cross-sectional view schematically showing a multilayer structure according to the fourth embodiment of the present invention.

  Details of the present invention will be described below.

  The multilayer structure according to the present invention has a laminate in which five or more first layers containing a thermoplastic resin are laminated. At least one of the plurality of first layers includes a filler. In this way, a multilayer structure having a multilayer body in which a large number of first layers are stacked, and at least one of the plurality of first layers including a filler is produced. The body's tensile strength can be increased. Furthermore, the mechanical strength of the multilayer structure can be increased. When the number of stacked layers of the first layer is 5 or more when the thickness of the stacked body is the same, the number of stacked layers of the first layer is more than that of 4 or less. The tensile strength of the structure is increased. Furthermore, since the multilayer structure has a laminate in which at least one of the plurality of first layers includes a filler, the tensile strength of the multilayer structure is increased. Therefore, the tear strength, tensile strength, and breaking strength of the multilayer structure are increased. Furthermore, when a carbon material having a graphene structure such as a carbon nanotube is used as the filler, the thermal conductivity and electrical characteristics of the multilayer structure are further enhanced.

  The multilayer structure according to the present invention may be the above laminate, or may include the laminate and other layers. The laminate itself may be a multilayer structure according to the present invention. In the multilayer structure according to the present invention, other layers may be laminated on the laminate. The multilayer structure according to the present invention is the above-mentioned laminated body or includes at least the above-mentioned laminated body.

  The multilayer structure according to the present invention preferably includes a laminate in which the first layer is laminated by 10 layers or more. Also in this case, the tensile strength of the multilayer structure can be considerably increased. When the number of stacked layers of the first layer is 10 or more when the thickness of the stacked body is the same, the number of stacked layers of the first layer is more than that of 9 layers. The tensile strength of the structure is increased. Since the tensile strength of the multilayer structure is further increased, the number of the first layers stacked is more preferably 20 layers or more, and still more preferably 30 layers or more.

  The multilayer structure according to the present invention has a laminate in which five or more first layers containing a thermoplastic resin are laminated, and the multilayer has a multi-layer structure even when the average thickness of the first layer is 10 μm or less. The tensile strength of the structure can be significantly increased. If the average thickness of the first layer is 10 μm or less so that the number of stacked layers of the first layer increases when the thickness of the stacked body is the same, the number of stacked layers of the first layer decreases. As described above, the tensile strength is further increased as compared with the case where the average thickness of the first layer exceeds 10 μm.

  Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

  FIG. 1 schematically shows a multilayer structure according to the first embodiment of the present invention in a cross-sectional view. A multilayer structure 1 illustrated in FIG. 1 is a stacked body 2 in which a plurality of first layers 11A to 11K are stacked. The first layers 11A to 11K include a filler X. The stacked body 2 is configured by stacking at least five first layers 11A to 11K. Specifically, the laminate 2 is configured by laminating 11 first layers 11A to 11K.

  The first layers 11A to 11K include a thermoplastic resin. The first layers 11A to 11K include a filler X. At least one of the first layers 11A to 11K may contain a filler, and all the layers of the first layers 11A to 11K may contain a filler. The first layers 11 </ b> A to 11 </ b> K are stacked in the thickness direction of the stacked body 2. The compositions of the first layers 11A to 11K may be the same or different. The compositions of the first layers 11A to 11K are preferably the same. The composition of components other than the fillers of the first layers 11A to 11K may be the same or different. The compositions of the components other than the fillers of the first layers 11A to 11K are preferably the same.

  FIG. 2 is a cross-sectional view schematically showing a multilayer structure according to the second embodiment of the present invention. A multilayer structure 21 illustrated in FIG. 2 is a stacked body 22 in which a plurality of first layers 31A to 31F and 32A to 32E are stacked. The first layers 31A to 31F include a filler. The laminate 22 is configured by laminating at least five first layers 31A to 31F and 32A to 32E. Specifically, the laminate 22 is configured by laminating eleven first layers 31A to 31F and 32A to 32E.

  The first layers 31A to 31F and 32A to 32E include a thermoplastic resin. The first layers 31 </ b> A to 31 </ b> F include a filler X. At least one of the first layers 31A to 31F may include a filler. The first layers 32A to 32E do not contain a filler. The compositions of the first layers 31A to 31F and 32A to 32E may be the same or different. The compositions of the first layers 31A to 31F and 32A to 32E are preferably the same. The compositions of the first layers 31A to 31F may be the same or different. The compositions of the first layers 31A to 31F are preferably the same. The compositions of the first layers 32A to 32E may be the same or different. The compositions of the first layers 32A to 32E are preferably the same. The composition of components other than the fillers of the first layers 31A to 31F may be the same or different. The compositions of the components other than the fillers of the first layers 31A to 31F are preferably the same.

  The first layers 31A to 31F and the first layers 32A to 32E have different thicknesses. The thickness of the first layers 31A to 31F is thinner than the thickness of the first layers 32A to 32E. Thus, the thickness of the plurality of first layers may be the same or different. Of the relatively thin first layers 31A to 31F and the relatively thick first layers 32A to 32E, the relatively thin first layers 31A to 31F may contain a filler. preferable. The compositions of the first layers 31A to 31F and the first layers 32A to 32E may be the same or different. The first layers 31 </ b> A to 31 </ b> F and the first layers 32 </ b> A to 32 </ b> E are alternately stacked in the thickness direction of the stacked body 22. That is, the stacked body 22 includes the first layer 31A, the first layer 32A, the first layer 31B, the first layer 32B, the first layer 31C, the first layer 32C, the first layer 31D, The first layer 32D, the first layer 31E, the first layer 32E, and the first layer 31F are stacked in this order. The first layers 32A to 32E are sandwiched between the first layers 31A to 31F. The first layers 32A to 32E are separated from each other by the first layers 31A to 31F, respectively.

  FIG. 3 is a cross-sectional view schematically showing a multilayer structure according to the third embodiment of the present invention. A multilayer structure 41 shown in FIG. 3 includes a laminate 2 shown in FIG. 1, a second layer 42 laminated on the first surface 2 a of the laminate 2, and a first surface 2 a of the laminate 2. And a second layer 43 stacked on the opposite second surface 2b. The second layers 42 and 43 are surface layers. The composition of the second layer 42 and the second layer 43 may be the same or different. One second layer 42 may be stacked only on the first surface 2a of the stacked body 2, and the second layer 43 may not be stacked on the second surface 2b. The two second layers 42 and 43 are preferably laminated one by one on the first surface 2 a and the second surface 2 b of the laminate 2. The second layers 42 and 43 preferably contain a thermoplastic resin.

  By providing the second layer, the thickness of the second layer can be made larger than that of the first layer. The thickness of the second layer may be greater than the thickness of the first layer. Moreover, it is also possible to form embossing in the outer surface of a 2nd layer as needed. In addition, the tensile strength of the multilayer structure 41 which has the laminated body 2 and the 2nd layers 42 and 43 becomes high, so that the tensile strength of the laminated body 2 is high.

  FIG. 4 is a cross-sectional view schematically showing a multilayer structure according to the fourth embodiment of the present invention. The multilayer structure 51 shown in FIG. 4 includes the laminate 22 shown in FIG. 2, the second layer 42 laminated on the first surface 22 a of the laminate 22, and the first surface 22 a of the laminate 22. And a second layer 43 stacked on the opposite second surface 22b.

  The number of laminated first layers in the laminate is at least 5 layers, preferably 10 layers or more, more preferably 20 layers or more, still more preferably 30 layers or more, particularly preferably 40 layers or more, and most preferably More than 80 layers. When the number of stacked first layers is large, the tensile strength of the multilayer structure is increased. The upper limit of the number of stacked first layers in the stacked body can be appropriately changed in consideration of the thickness of the multilayer structure, and is not particularly limited. The number of stacked first layers in the stacked body may be 20000 layers or less, or 20000 layers or more. From the viewpoint of obtaining a multilayer structure having high transparency, the number of stacked first layers is preferably 5000 layers or less, more preferably 1500 layers or less, still more preferably 1000 layers or less, and particularly preferably 800 layers or less. Most preferably, it is 400 layers or less.

  From the viewpoint of further increasing the tensile strength of the multilayer structure, the average thickness of the first layer is preferably 5 nm or more, more preferably 50 nm or more, still more preferably 100 nm or more, particularly preferably 500 nm or more, preferably It is 200 μm or less, more preferably 100 μm or less, still more preferably 10 μm or less, particularly preferably 5 μm or less, and most preferably 1 μm or less. From the viewpoint of further increasing the tensile strength of the multilayer structure, the thickness of each first layer (each thickness of all the first layers) is preferably 50 nm or more, more preferably 100 nm or more, More preferably, it is 500 nm or more, preferably 40 μm or less, more preferably 5 μm or less, and further preferably 1 μm or less. The thickness per layer of the first layer (each thickness of all first layers) may be less than 300 μm, 200 μm or less, or 160 μm or less. The thickness of each of the two first layers located on the outermost surface of the laminate is preferably 40 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. The thickness of each of the two first layers located on the outermost surface of the laminate may be less than 300 μm, 200 μm or less, or 160 μm or less.

  The thickness of the laminate is preferably 0.03 mm or more, more preferably 0.05 mm or more, further preferably 0.1 mm or more, preferably 3 mm or less, more preferably 1.5 mm or less, and even more preferably 1 mm or less. . When the thickness of the laminate is not less than the lower limit, the tensile strength of the multilayer structure is further increased. When the thickness of the laminate is not more than the above upper limit, the transparency of the multilayer structure is further increased.

  The thickness of the multilayer structure is preferably 0.03 mm or more, more preferably 0.05 mm or more, further preferably 0.1 mm or more, preferably 3 mm or less, more preferably 1.5 mm or less, and even more preferably 1 mm or less. is there. When the thickness of the multilayer structure is not less than the above lower limit, the tensile strength of the multilayer structure is further increased. When the thickness of the multilayer structure is not more than the above upper limit, the transparency of the multilayer structure is further increased.

  From the viewpoint of further improving the tensile strength of the multilayer structure, the thickness of each of the second layers (each thickness of all second layers) is preferably 5 nm or more, more preferably 50 nm or more, More preferably, it is 100 nm or more, particularly preferably 1 μm or more, most preferably 10 μm or more, preferably 1000 μm or less, more preferably 600 μm or less, still more preferably 200 μm or less, particularly preferably 100 μm or less, and most preferably 50 μm or less. The thickness of each of the second layers (each thickness of all the second layers) may exceed 1 μm, may exceed 5 μm, may exceed 40 μm, and may be 160 μm. It may be over and may be over 200 micrometers.

  When the thickness of the second layer is not less than the above lower limit, the thickness of the multilayer structure does not become too thick.

  When the thickness of the laminate is T, the thickness of the second layer is preferably more than 0.2T, more preferably 0.4T or more, preferably 3T or less, more preferably 1T or less, still more preferably Is 0.8T or less, particularly preferably 0.6T or less.

  At least one of the plurality (five or more layers) of the first layers includes a filler. Therefore, the tensile strength of the multilayer structure is further increased. That is, the use of the filler greatly contributes to the improvement of the tensile strength of the multilayer structure. Moreover, the said 2nd layer may contain the filler and does not need to contain the filler.

  From the viewpoint of further increasing the tensile strength of the multilayer structure, the filler material is preferably a carbon material having a graphene structure. Examples of the carbon material having the graphene structure include carbon nanotubes. From the viewpoint of further increasing the tensile strength of the multilayer structure, the filler material is preferably a carbon nanotube.

  Moreover, it is preferable that the aspect ratio of the said filler exceeds 1 from a viewpoint of raising the tensile strength of a multilayer structure further. Furthermore, from the viewpoint of further increasing the tensile strength of the multilayer structure, the filler is preferably a non-spherical filler, more preferably a rod-like filler or a plate-like filler, and further a plate-like filler. preferable. In order to further increase the tensile strength of the multilayer structure, the aspect ratio of the filler is preferably 1.5 or more, more preferably 2 or more, further preferably 2.5 or more, and 3 or more. It is particularly preferred that

  The non-spherical filler is a non-spherical filler. The non-spherical filler, rod-like filler and plate-like filler each have a length direction. In addition, when the filler material is a carbon material having a graphene structure such as a carbon nanotube, the filler generally has a length direction.

  From the viewpoint of further increasing the tensile strength of the multilayer structure, the angle formed by the length direction of each filler in the filler-containing layer with respect to the direction in which the length directions of all the fillers in the layer containing the filler are averaged. The average of absolute values (hereinafter, this average value is also referred to as angle α) is preferably 30 ° or less. The angle α is more preferably 20 ° or less, further preferably 10 ° or less, particularly preferably 6 ° or less, and most preferably 3 ° or less. The lower limit of the angle α is not particularly limited, but is preferably 0 ° or more. By controlling the orientation of the filler so that the angle α is not more than the upper limit, the tensile strength in the direction orthogonal to the stacking direction of the first layer in the multilayer structure is considerably increased. By using the composition for forming the first layer containing the thermoplastic resin and the filler, and obtaining the laminate by a multilayer melt extrusion method, the angle α in the layer containing the filler is made the upper limit or less. Is easy. The method for obtaining the angle α is not particularly limited, but in the first layer containing the thermoplastic resin and the filler, a thin film slice at the center in the thickness direction is prepared, and the thin film slice is magnified using a scanning electron microscope. This can be determined by observing the filler at 10,000 times and measuring the average of the absolute values of the angles formed in the length direction of the observed filler.

The first layer may contain bubbles or may not contain bubbles. The second layer may contain bubbles or may not contain bubbles. When the first layer contains bubbles, the average bubble diameter of the bubbles is preferably less than 200 nm. When the first layer contains bubbles, the expansion ratio is not particularly limited, but is preferably 1.1 times or more. The method of incorporating bubbles in the first layer is not particularly limited, and examples of the foam material include a method using a chemical foam material such as azodicarbonimide (ADCA), a method using a gas such as CO _{2, and the} like.

  Regarding the “average bubble diameter”, when the bubbles are closed cells and are spherical, the average bubble diameter is obtained from the diameter of the bubbles. When the bubble is a closed bubble and has a shape other than a true spherical shape, the average bubble diameter is obtained from the longest length connecting two points on the outer periphery of the bubble, that is, the maximum diameter. In addition, even when the bubbles are continuous bubbles, the average bubble diameter is determined from the longest length connecting two points on the outer periphery of the bubbles, that is, the maximum diameter. The average bubble diameter indicates an average value of the bubble diameters of at least 10 bubbles, and is preferably an average value of the bubble diameters of 10 arbitrarily selected bubbles.

  Hereafter, the detail of each component contained in the multilayer structure which concerns on this invention is demonstrated.

(Thermoplastic resin)
The first layer includes a thermoplastic resin. The second layer preferably contains a thermoplastic resin. The thermoplastic resin is not particularly limited. A conventionally known thermoplastic resin can be used as the thermoplastic resin contained in the first and second layers. As for a thermoplastic resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the thermoplastic resin include polyolefin resin, PET (polyethylene terephthalate) resin, PBT (polybutylene terephthalate) resin, polycarbonate resin, EVA (ethylene-vinyl acetate copolymer) resin, polystyrene resin, vinyl chloride resin, ABS. Examples thereof include thermoplastic resins such as (acrylonitrile-butadiene-styrene copolymer) resin, AS (acrylonitrile-styrene copolymer) resin, polyvinyl acetal resin, thermoplastic elastomer, and (meth) acrylic resin. Each of the first layer and the second layer preferably contains a polyolefin resin, a polycarbonate resin, an ethylene-vinyl acetate copolymer resin, a polystyrene resin, or a polyvinyl acetal resin. From the viewpoint of further improving the tensile strength, the first layer preferably contains a polyvinyl acetal resin as the thermoplastic resin, and more preferably contains a polyvinyl acetal resin and a plasticizer. Further, from the viewpoint of further improving the tensile strength, the first layer preferably contains a polycarbonate resin as the thermoplastic resin. The thermoplastic resin may be alloyed or blended with a polymer compound.

  The polyolefin resin is not particularly limited. For example, a homopolymer such as ethylene, propylene or α-olefin, a copolymer of ethylene and propylene, a copolymer of ethylene and α-olefin, and propylene and α-olefin. And a copolymer of two or more α-olefins. As for the said polyolefin resin, only 1 type may be used and 2 or more types may be used together.

  The α-olefin is not particularly limited, and examples thereof include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene and 1-octene.

  Examples of the vinyl chloride resin include vinyl chloride homopolymers, copolymers of vinyl chloride and polymerizable monomers other than vinyl chloride that can be polymerized with the vinyl chloride, and polymer resins other than vinyl chloride polymers. Examples thereof include a graft copolymer obtained by grafting a vinyl polymer.

  The polymerizable monomer is not particularly limited as long as it has a reactive double bond. Examples of the polymerizable monomer include α-olefins such as ethylene, propylene and butylene, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as butyl vinyl ether and cetyl vinyl ether, and methyl (meth) acrylate. (Meth) acrylates such as ethyl (meth) acrylate and phenyl (meth) acrylate, aromatic vinyls such as styrene and α-methylstyrene, vinyl halides such as vinylidene chloride and vinyl fluoride, and And N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide. As for the said polymerizable monomer, only 1 type may be used and 2 or more types may be used together.

  The polymer resin is not particularly limited. For example, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene-ethyl (meth) acrylate copolymer, ethylene-methyl (meth) acrylate. Examples include copolymers, ethylene-propylene copolymers, acrylonitrile-butadiene copolymers, polyurethane resins, chlorinated polyethylene resins, and chlorinated polypropylene resins. As for the said polymeric resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the ABS resin include acrylonitrile-butadiene-styrene terpolymer.

  In order to improve heat resistance, the thermoplastic resin may be copolymerized with aromatic vinyls such as α-methylstyrene and N-phenylmaleimide.

  The polyvinyl acetal resin is not particularly limited, and examples thereof include polyvinyl butyral resin.

  The thermoplastic elastomer is not particularly limited, and examples thereof include styrene / butadiene elastomer, ethylene / propylene elastomer, and acrylic elastomer.

  The molecular weight and molecular weight distribution of the thermoplastic resin are not particularly limited. The weight average molecular weight of the thermoplastic resin is preferably 5000 or more, more preferably 20000 or more, preferably 5 million or less, more preferably 300,000 or less. The molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of the thermoplastic resin is preferably 2 or more, more preferably 3 or more, preferably 80 or less, more preferably 40 or less.

  The weight average molecular weight (Mw) and the number average molecular weight (Mn) are values obtained using polystyrene as a standard substance using gel permeation chromatography (GPC). The weight average molecular weight (Mw) and number average molecular weight (Mn) were measured by a measuring device manufactured by Waters (column: Shodex GPC LF-804 (length 300 mm) x 2 manufactured by Showa Denko KK), measuring temperature: 40 ° C., flow rate: It means a value measured using 1 mL / min, solvent: tetrahydrofuran, standard substance: polystyrene).

(Filler)
As described above, at least one of the plurality (five layers or more) of the first layers includes a filler. Therefore, the tensile strength of the multilayer structure is further increased. Moreover, the said 2nd layer may contain the filler and does not need to contain the filler.

  From the viewpoint of further increasing the tensile strength of the multilayer structure, the filler material is preferably a carbon material having a graphene structure.

  Preferable examples of the carbon material include layered graphite, exfoliated graphite, graphite, and carbon nanotube. The filler is preferably exfoliated graphite. The exfoliated graphite is a laminate of a plurality of graphene sheets. The exfoliated graphite is obtained by exfoliating layered graphite, and is a laminate of graphene sheets thinner than layered graphite. The number of graphene sheets laminated in the exfoliated graphite is two or more. The number of graphene sheets laminated in the exfoliated graphite is preferably smaller than the number of laminated layered graphite, and is preferably 200 layers or less. The aspect ratio of the exfoliated graphite is relatively large. Therefore, when the multilayer structure includes the layer containing the filler, the tensile strength in the direction perpendicular to the stacking direction of the first layer in the multilayer structure is considerably increased.

  Further, from the viewpoint of further increasing the tensile strength of the multilayer structure, the filler is preferably a non-spherical filler, more preferably a rod-like filler or a plate-like filler, and further a plate-like filler. preferable.

  The aspect ratio of the filler is preferably more than 1, more preferably 1.1 or more, even more preferably 2 or more, still more preferably 2.5 or more, particularly preferably 3 or more, preferably 500 or less, more preferably 300 or less, more preferably 100 or less, particularly preferably 50 or less. When the filler material is a carbon material having a graphene structure, or when the filler is a rod-like filler or a plate-like filler, the aspect ratio of the filler is preferably 10 or more, more preferably 90 or more. The aspect ratio is a ratio of a longitudinal dimension to a lateral dimension. When the filler material is a carbon material having a graphene structure, the aspect ratio is a ratio of a longitudinal dimension in the graphene sheet lamination surface direction to a short dimension in the graphene sheet lamination surface direction. When the aspect ratio is not less than the above lower limit and not more than the above upper limit, the tensile strength of the multilayer structure is further increased.

  When the filler material is a carbon material having a graphene structure, or when the filler is a rod-like filler or a plate-like filler, the thickness of the layer containing the filler is preferably at least 1 times the thickness of the filler, preferably Is more than 1 time, more preferably 1.1 times or more, preferably 100 times or less, more preferably 10 times or less, still more preferably 3 times or less.

  In the layer containing the filler, the content of the filler is preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, still more preferably 1 part by weight or more with respect to 100 parts by weight of the thermoplastic resin. The amount is particularly preferably 2 parts by weight or more, preferably 100 parts by weight or less, more preferably 50 parts by weight or less, still more preferably 20 parts by weight or less, and particularly preferably 10 parts by weight or less.

  From the viewpoint of further increasing the tensile strength of the multilayer structure, the laminate is preferably obtained by stretching, and the laminate is preferably a stretched laminate. The multilayer structure is preferably obtained by stretching the laminate. The magnification for stretching the laminate is not particularly limited. By stretching the laminate, the orientation of the filler is increased, and the average absolute value of the angles formed by the length directions of the fillers in the layer containing the filler can be reduced. As a result, the mechanical properties of the multilayer structure are increased.

(Other ingredients)
Each of the first and second layers in the multilayer structure according to the present invention includes a plasticizer, an ultraviolet absorber, an antioxidant, a light stabilizer, a flame retardant, an antistatic agent, a pigment, a dye, Additives such as an adhesive strength modifier, a moisture-proofing agent, a fluorescent brightening agent, and an infrared absorber may be included.

(Manufacturing method of multilayer structure)
The method for producing a multilayer structure according to the present invention is not particularly limited. Examples of the method for producing a multilayer structure according to the present invention include a wet lamination method, a dry lamination method, an extrusion coating method, a multilayer melt extrusion method, a hot melt lamination method, and a heat lamination method.

  The multilayer structure according to the present invention is preferably obtained by a multilayer melt extrusion method because it is easy to produce and a multilayer structure that is more excellent in tensile strength can be obtained. Examples of the multilayer melt extrusion method include a multi-manifold method and a feed block method.

  From the viewpoint of easily producing a multilayer structure and further improving the tensile strength, the method for producing a multilayer structure according to the present invention is a laminate in which five or more first layers containing a thermoplastic resin are laminated. Preferably, the method includes a step of forming a laminate in which at least one of the plurality of first layers contains a filler by a multilayer melt extrusion method. From the viewpoint of producing a multilayer structure more easily and further improving the tensile strength, it is preferable to form the laminate by a multi-manifold method or a feed block method. Further, in the method for producing a multilayer structure according to the present invention, one of the second layers is laminated only on the first surface of the laminate, or two of the second layers are laminated on the laminate. It is preferable to include a step of laminating one layer at a time on the first surface and a second surface opposite to the first surface.

  Next, the manufacturing method of the laminated body in a multilayer structure is demonstrated.

  First, a composition for forming a first layer containing a thermoplastic resin and a filler is prepared. Moreover, the composition for forming a 2nd layer is prepared as needed. For example, the filler can be uniformly dispersed in the thermoplastic resin by kneading under heating using a twin screw kneader or a twin screw extruder. Examples of the twin screw kneader include a plast mill.

  In addition, when the filler which is exfoliated graphite is disperse | distributed uniformly in a thermoplastic resin, it is preferable to knead | expand expanded graphite with a thermoplastic resin under a heating. By expanding and kneading the expanded graphite with a thermoplastic resin under heating, the expanded graphite is separated into a plurality of exfoliated graphite, and the exfoliated graphite is uniformly dispersed in the thermoplastic resin. The expanded graphite can be obtained by increasing the interlayer distance of the layered graphite by an electrochemical method in which electrolyte ions such as nitrate ions are inserted between the layers of the layered graphite.

  Next, the whole or at least part of the first layer is laminated by co-extrusion and molding the composition for forming the first layer using a manufacturing apparatus. Specifically, the composition for forming the first layer is introduced into both the first extruder (main extruder) and the second extruder (sub-extruder), and the first extruder And the composition for forming the said 1st layer is extruded simultaneously from a 2nd extruder. When extruding the composition for forming the first layer, the composition for forming the second layer may be extruded. The composition for forming the first layer extruded from the first extruder and the second extruder is sent to a feed block. In a feed block, the composition for forming the said 1st layer extruded from the 1st extruder and the 2nd extruder joins so that it may overlap alternately. Thereby, the composition for forming the first layer can be laminated.

  By including a filler in one of the compositions for forming the first layers that are alternately stacked, a stacked body in which layers containing fillers and layers not containing fillers are alternately stacked can be obtained. By including a filler in both of the compositions for forming the first layers that are alternately stacked, a stacked body in which layers including fillers are stacked can be obtained.

  Note that the method for laminating the composition for forming the first layer is not limited to the above-described method. The composition for forming the first layer can be laminated by an appropriate coextrusion molding method and manufacturing apparatus.

  Next, a plurality of multi-layer blocks that can be divided and laminated are attached to the downstream portion of the feed block to obtain a multi-layer structure.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples.

Example 1
To 100 parts by weight of PC resin (Mitsubishi Gas Chemical Co., Ltd. Iupilon E2000) which is a thermoplastic resin, 5 parts by weight of carbon nanotubes (Hodogaya Chemical Co., Ltd., diameter 65 nm, length direction dimension 3 μm in the z direction) are added. A composition A for forming the first layer was obtained.

  Composition A for forming the first layer was supplied to the main extruder. Further, PC resin (Iupilon E2000 manufactured by Mitsubishi Gas Chemical Company), which is a thermoplastic resin, was supplied to the sub-extruder. A multi-layer feed block was attached to the tip of the main extruder and the sub-extruder. The total thickness of the first layer extruded from the main extruder and the sub-extruder is set to 800 μm, and the first layer extruded from the main extruder and the first layer extruded from the sub-extruder are By alternately laminating a total of five first layers, a laminate having the thickness shown in Table 1 below was obtained as a multilayer structure. In addition, the 1st layer containing a filler was 3 layers.

(Examples 2 to 11)
The number of layers of the first layer was increased from 5 to 1280 layers as shown in Table 1 by attaching several sets of multilayer blocks, and the carbon nanotubes used in Example 1 for the sub-extruder Was added in the same manner as in Example 1 except that the amount of filler was changed as shown in Table 1 to obtain a multilayer structure. In Examples 3, 4, 7, 8 and 10, no carbon nanotubes were added to the sub-extruder. The first layers containing the filler in that case were 6, 12, 24, 48, and 102 layers, respectively.

(Examples 12 and 13)
The total thickness of the first layer is set to 200 μm, the thickness of the second layer is set to 600 μm, the thicknesses of the front and back layers are each 300 μm, and the total of the first layer is 5 layers as shown in Table 1. A multilayer structure was obtained in the same manner as in Example 1 except that the layers were laminated. In Example 13, the carbon nanotubes used in Example 1 were also added to the sub-extruder, and the multilayer structure was the same as in Example 1 except that the amount of filler was changed as shown in Table 1. Got the body.

(Evaluation)
(1) Tensile strength Tensile strength measurement was carried out by preparing a dumbbell-shaped test piece in accordance with a test method for tensile properties of plastic according to JIS K7161, and using an autograph AG-1 manufactured by Shimadzu Corporation.

(2) Volume resistance The volume low efficiency was measured using a Loresta GP manufactured by Mitsubishi Chemical in accordance with the four-end needle method of conductive plastic of JIS K7194.

(3) Orientation angle α of the filler
A thin film slice at the center in the thickness direction was prepared from the obtained multilayer structure and single-layer structure, and the thin film slice was observed at a magnification of 10,000 using a scanning electron microscope. By measuring the average absolute value of the angles formed by the length directions of all fillers observed in the range of 20 μm in length × 20 μm in width, in the direction in which the length directions of all fillers in the layer containing the filler were averaged On the other hand, the average of the absolute value of the angle formed by the length direction of each filler in the layer containing the filler was calculated. The calculated average value was taken as the filler orientation angle α.

  The results are shown in Table 1 below. In addition, in the following Table 1, the compounding quantity of a filler shows the compounding quantity (weight part) of the filler with respect to 100 weight part of thermoplastic resins.

DESCRIPTION OF SYMBOLS 1 ... Multilayer structure 2 ... Laminated body 2a ... 1st surface 2b ... 2nd surface 11A-11K ... 1st layer 21 ... Multilayer structure 22a ... 1st surface 22b ... 2nd surface 31A-31F, 32A to 32E: first layer 41: multilayer structure 42, 43 ... second layer 42a, 43a ... outer surface 51 ... multilayer structure X: filler

Claims (17)

Having a laminate in which five or more first layers containing a thermoplastic resin are laminated;
The average thickness of the first layer is 5 nm or more and 200 μm or less,
At least one of the plurality of first layers includes a filler;
The average absolute value of the angles formed by the length directions of the fillers in the layer containing the filler is 30 ° or less with respect to the direction in which the length directions of all the fillers in the layer containing the filler are averaged. , Multilayer structure.   The multilayer structure according to claim 1, wherein the filler material is a carbon material having a graphene structure.   The multilayer structure according to claim 1 or 2, wherein the filler material is a carbon nanotube.   The multilayer structure according to any one of claims 1 to 3, wherein an aspect ratio of the filler exceeds 1.   The multilayer structure according to claim 1 or 2, wherein the filler is a rod-like filler or a plate-like filler.   The multilayer structure according to any one of claims 1 to 5, comprising a laminate in which the first layer is laminated by 10 layers or more.   The multilayer structure according to any one of claims 1 to 6, wherein the average thickness of the first layer is 5 nm or more and 10 µm or less.   The multilayer structure according to any one of claims 1 to 7, wherein a thickness of the laminate is 0.03 mm or more and 3 mm or less.   The multilayer structure according to any one of claims 1 to 8, wherein the thermoplastic resin is a polycarbonate resin. A second layer different from the first layer;
One of the second layers is laminated only on the first surface of the laminate, or two of the second layers are the first surface and the first surface of the laminate. The multilayer structure according to any one of claims 1 to 9, wherein one layer is laminated on the opposite second surface.   The multilayer structure according to claim 10, wherein the thickness of each of the second layers is 5 nm or more and 1000 μm or less.   The multilayer structure according to any one of claims 1 to 11, wherein at least one of the plurality of first layers contains bubbles.   The multilayer structure according to claim 1, wherein the laminate is obtained by stretching.   The multilayer structure according to any one of claims 1 to 13, wherein the laminate is obtained by a multilayer melt extrusion method. It is a manufacturing method of the multilayer structure according to any one of claims 1 to 14,
It is a laminate in which five or more first layers containing a thermoplastic resin are laminated, and the average thickness of the first layers is 5 nm or more and 200 μm or less, and a plurality of the first layers are included. Comprising a step of forming a laminate including at least one layer containing a filler by a multilayer melt extrusion method,
The average absolute value of the angles formed by the length directions of the fillers in the layer containing the filler is 30 ° or less with respect to the direction in which the length directions of all the fillers in the layer containing the filler are averaged. A method for producing a multilayer structure, wherein a multilayer structure is obtained.   The method for producing a multilayer structure according to claim 15, wherein the laminate is formed by a multi-manifold method or a feed block method.   Laminating one second layer only on the first surface of the stack, or two second layers opposite the first surface and the first surface of the stack The manufacturing method of the multilayer structure of Claim 15 or 16 further provided with the process of laminating | stacking one layer at a time on the 2nd surface.

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