JP2019217700A - Laminated film, laminate and molded body - Google Patents

Abstract

To provide a laminated film which can suitably join two or more members having predetermined thickness or thicker.SOLUTION: A laminated film 10 for joining a first member and a second member has at least a first heat weldable resin layer 1, an intermediate layer 3 and a second heat weldable resin layer 2 in this order, and has a tensile elastic modulus of 1,500 MPa or more, in which at least one thickness of the first member and the second member is 1 mm or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laminated film, a laminate, and a molded product.

  Members of industrial products are made of various materials such as metals, resins, and ceramics. Conventionally, these members are formed in a desired shape in advance, and then joined by a joining member such as an adhesive using a curable resin, a screw, a rivet, or the like (see, for example, Patent Document 1).

JP 2008-111536 A

  Joining using joining members such as screws and rivets requires a complicated joining operation. In addition, the adhesive takes a long time to apply, and it is difficult to control the thickness of the adhesive layer, so that the adhesive strength tends to be uneven. Furthermore, many members of industrial products have a considerable thickness, and such members are liable to be subjected to shear stress parallel to the bonding surface when bonded by an adhesive to form a laminate. However, conventional adhesives do not have sufficient strength against the shear stress of the bonded laminate. Therefore, as a method of joining members of industrial products, there is no need to use joining members such as conventional adhesives, screws, and rivets, and a laminate having excellent strength against shear stress parallel to the joining surface is provided. There is a need to develop new approaches that can be given.

  The main object of the present invention is to provide a laminated film that can suitably join two or more members, at least one of which has a predetermined thickness or more. More specifically, a main object of the present invention is to provide a laminated film having excellent strength against shear stress parallel to a joining surface in a molded product obtained after joining two or more members having a predetermined thickness or more. Further, another object of the present invention is to provide a molded article using the laminated film and having excellent strength against shear stress parallel to a bonding surface.

  The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, at least one of them is a laminated film for joining at least two members having a predetermined thickness (for example, a first member and a second member) by heat welding, and at least one of the first heat-welding resin layer and A laminated film having an intermediate layer and a second heat-sealable resin layer in this order, and having a specific tensile modulus of elasticity, improves the strength against shear stress parallel to the joining surface in a molded product obtained after joining. I found out that it can be done. The present invention has been completed by further study based on such knowledge.

That is, the present invention provides the following aspects of the invention.
Item 1. A laminated film for joining the first member and the second member,
The laminated film includes at least a first heat-welding resin layer, an intermediate layer, and a second heat-welding resin layer in this order,
A tensile modulus of 1500 MPa or more;
A laminated film, wherein at least one of the first member and the second member has a thickness of 1 mm or more.
Item 2. Item 2. The laminated film according to item 1, wherein both the first member and the second member have a thickness of 1 mm or more.
Item 3. Item 3. The laminated film according to Item 1 or 2, wherein the intermediate layer is a film.
Item 4. Item 4. The laminated film according to any one of Items 1 to 3, wherein at least one of the first heat-welding resin layer and the second heat-welding resin layer contains a modified polyolefin.
Item 5. Item 5. The laminated film according to any one of Items 1 to 4, wherein the tensile modulus of the intermediate layer is 1500 MPa or more.
Item 6. Item 6. The laminated film according to any one of Items 1 to 5, wherein one of the first member and the second member is made of metal.
Item 7. Item 7. The laminated film according to any one of Items 1 to 6, wherein one of the first member and the second member is made of fiber-reinforced plastic.
Item 8. Item 8. The laminated film according to Item 7, wherein the fibers in the fiber reinforced plastic are glass fibers or carbon fibers.
Item 9. Any one of items 1 to 8, wherein when at least one of the first heat-welding resin layer and the second heat-welding resin layer is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is detected. The laminated film according to the above.
Item 10. A laminate, wherein the first member and the second member or the second member precursor are laminated via the laminated film according to any one of Items 1 to 9.
Item 11. A molded article in which the first member and the second member are in a joined state and a molded state via the laminated film according to any one of Items 1 to 9.

  ADVANTAGE OF THE INVENTION According to this invention, the laminated film excellent in intensity | strength with respect to the shear stress parallel to a joining surface can be provided in the molded object obtained after joining of two or more members which have at least any one of a predetermined thickness. Further, according to the present invention, it is also possible to provide a molded article using the laminated film and having excellent strength against shear stress parallel to the joining surface.

It is a schematic sectional drawing of an example of the laminated film of this invention. It is a schematic sectional drawing of an example of the laminated film of this invention. It is a schematic sectional drawing of an example of the laminated film of this invention. It is a schematic sectional drawing of an example of the laminated film of this invention. It is a schematic sectional drawing of an example of the molded object of this invention. It is a schematic diagram for explaining the measuring method of the seal strength. It is a schematic diagram for explaining an example of the manufacturing method of the molded object of the present invention. It is a schematic diagram for explaining an example of the manufacturing method of the molded object of the present invention. It is a schematic sectional drawing of an example of the molded object manufactured by the manufacturing method of the molded object of this invention. It is a schematic diagram for demonstrating the other example of the manufacturing method of the molded object of this invention. It is a schematic diagram for demonstrating the other example of the manufacturing method of the molded object of this invention. It is a schematic diagram for demonstrating the other example of the manufacturing method of the molded object of this invention. It is a schematic diagram for demonstrating the measuring method of a shear strength. It is a conceptual diagram of the position change of a probe in the displacement amount measurement of a probe. FIG. 4 is a schematic diagram showing a position of a surface of a heat-welding resin layer at an end of a laminated film where a probe is installed in measuring a displacement amount of the probe. It is a schematic diagram for demonstrating the measuring method of peel strength.

  The laminated film of the present invention is a laminated film for joining a first member and a second member, and the laminated film includes a first heat-welding resin layer, an intermediate layer, and a second heat-welding resin layer. Are provided in this order. Hereinafter, the laminated film of the present invention, a molded article using the laminated film, and a method for producing these are described in detail.

  In this specification, a numerical range indicated by “to” means “over” and “below”. For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. Laminated film The laminated film of the present invention is a laminated film for joining the first member and the second member. More specifically, the laminated film of the present invention has a structure in which the laminated film is disposed between the first member and the second member, and the first member and the second member are thermally welded through the laminated film to form the first film. Used for joining the member and the second member. In addition to the first member and the second member, another member may be joined using the laminated film of the present invention. That is, the laminated film of the present invention is a laminated film for joining at least two members by heat welding. Further, the laminated film of the present invention is a laminated film having a heat-welding property (heat-welding laminated film).

  For example, as shown in the schematic diagrams of FIGS. 1 to 4, the laminated film 10 of the present invention includes at least a first heat-welding resin layer 1, an intermediate layer 3, and a second heat-welding resin layer 2. In this order. The first heat-welding resin layer 1 constitutes one surface of the laminated film 10, and the second heat-welding resin layer 2 is formed on the opposite side of the laminated film 10 from the first heat-welding resin layer 1. Of the surface.

  As a specific example of the laminated structure of the laminated film 10 of the present invention, a laminated structure including a first heat-welding resin layer 1 / an intermediate layer 3 / a second heat-welding resin layer 2 in this order as shown in FIG. 1; A laminated structure including a first heat-welding resin layer 1 / intermediate layer 3 / thermoplastic resin layer 4 / second heat-welding resin layer 2 in this order as shown in FIG. 2; Laminated structure including heat-welding resin layer 1 / thermoplastic resin layer 4 / intermediate layer 3 / second heat-welding resin layer 2 in this order; first heat-welding resin layer 1 / thermoplastic as shown in FIG. A laminated configuration including a resin layer 4 / intermediate layer 3 / thermoplastic resin layer 4 / second heat-welding resin layer 2 in this order may be used. In addition, as described later, the first heat-welding resin layer 1 and the second heat-welding resin layer 2 are respectively formed on the molded body after the bonding, as long as it does not affect the strength against shear stress parallel to the bonding surface. It may have adhesiveness including an adhesive component. Further, the thermoplastic resin layer 4 may have a heat-welding property similarly to the first heat-welding resin layer 1 and the second heat-welding resin layer 2. In the laminated film of the present invention, another layer different from these layers may be further laminated. For example, although not shown, an adhesion promoter layer described later may be provided on one or both surfaces of the intermediate layer 3.

  From the viewpoint of low cost and simplification of the manufacturing process, it is preferable to make the laminated film thin, and the laminated film of the present invention has a first heat-welding resin layer 1 / intermediate layer 3 / second layer as shown in FIG. It is preferable to provide a three-layer laminated structure including the heat-welding resin layer 2 in this order. In addition, from the viewpoint of followability to the uneven shape or the like (that is, the property of leveling the uneven shape by injecting a resin into the concave portion in the uneven shape), it is preferable to increase the thickness of the laminated film. Preferably, a thermoplastic resin layer is provided between each layer of the first heat-welding resin layer 1 / the intermediate layer 3 / the second heat-welding resin layer 2. Specifically, a four-layer laminated structure including a first heat-welding resin layer 1 / intermediate layer 3 / thermoplastic resin layer 4 / second heat-welding resin layer 2 in this order as shown in FIG. 2; 3, a first heat-welding resin layer 1 / thermoplastic resin layer 4 / intermediate layer 3 / second heat-welding resin layer 2 as shown in FIG. It is preferable to have a five-layer laminated structure including the first heat-welding resin layer 1 / thermoplastic resin layer 4 / intermediate layer 3 / thermoplastic resin layer 4 / second heat-welding resin layer 2 in this order. Further, in the case where the first heat-welding resin layer 1 contains an adhesive component as long as it does not affect the strength against shear stress parallel to the bonding surface in the molded body after bonding, the laminated film of the present invention Is a laminated structure of five layers containing an adhesive component on both surfaces (specifically, a first heat-sealable resin layer 1 containing an adhesive component 1 / a thermoplastic resin layer 4 / an intermediate layer 3 / a thermoplastic resin layer 4 / Laminated configuration including second heat-welding resin layer 2 including an adhesive component in this order) or a four-layer configuration including an adhesive component on one surface (specifically, first thermal welding including an adhesive component) (Thermoplastic resin layer 1 / thermoplastic resin layer 4 / intermediate layer 3 / thermoplastic resin layer 4 / second heat-welding resin layer 2 containing no adhesive component in this order).

  From the viewpoint of low cost and suppression of the possibility of delamination, the number of layers of the laminated film of the present invention is preferably small, and a preferable lower limit is 3 or more, and a preferable upper limit is 5 or less. From the viewpoint of reducing the heat shrinkage in a high-temperature environment at the time of heat welding and improving the appearance after heat welding and suitably heat-welding two or more members, the number of layers of the laminated film of the present invention is as follows. , Preferably about 3 to 5, more preferably about 3 to 4.

  In addition, the area of one surface of the laminated film of the present invention can be appropriately set according to the size of the member to be thermally welded.

<Tensile modulus>
The lower limit of the tensile modulus of the laminated film 10 of the present invention is 1500 MPa or more. Thereby, the molded body after joining can be obtained as one having excellent strength against shear stress parallel to the joining surface. From the viewpoint of obtaining a molded article after joining as having superior strength against shear stress parallel to the joining surface, the tensile elastic modulus of the laminated film 10 of the present invention is preferably, as a lower limit, about 1500 MPa or more, It is more preferably at least 2,000 MPa, even more preferably at least about 3,000 MPa, particularly preferably at least about 5,000 MPa. There is no particular upper limit for the tensile modulus, but it is usually about 10,000 MPa or less, preferably about 8000 MPa or less, and more preferably about 7000 or less. That is, the range of the tensile elastic modulus is about 1500 to 10000 MPa, about 1500 to 8000 MPa, about 1500 to 7000 MPa, about 2000 to 10000 MPa, about 2000 to 8000 MPa, about 2000 to 7000 MPa, about 3000 to 10000 MPa, about 3000 to 8000 MPa. , About 3000 to 7000 MPa, about 5,000 to 10,000 MPa, about 5,000 to 8,000 MPa, and about 5,000 to 7000 MPa.

The tensile modulus is a value measured in accordance with JIS K7161: 2014. Specifically, a test piece (rectangular) obtained by cutting a film into a width of 25 mm and a length of 120 mm so that the MD becomes a long side. Was measured using a tensile compression tester (Tensilon RTC-1250A manufactured by Orientec Co., Ltd.) at a temperature of 25 ° C. under conditions of a tensile speed of 200 mm / min and a distance between chucks of 100 mm. Calculate from the first straight line part of the strain curve according to the following equation:
E = Δρ / Δε
E: Tensile modulus Δρ: Stress difference due to original mean cross-sectional area between two points on a straight line Δε: Strain difference between the same two points

  In the present invention, the direction corresponding to the MD of the laminated film 10 may be, for example, the same direction as the MD of the intermediate layer 3 of the laminated film 10 when the intermediate layer 3 is a film. In the present invention, the method of confirming the MD of the intermediate layer 3 of the laminated film 10 is as described in the tensile modulus of the intermediate layer 3 described later. When the intermediate layer 3 of the laminated film 10 is a fiber, the direction corresponding to the MD of the laminated film 10 is the same as the direction of the MD of the first heat-welding resin layer 1 and the second heat-welding resin layer 2. do it. The method of checking the MD of the first heat-welding resin layer 1 and the second heat-welding resin layer 2 is the same as the method of checking the MD of the intermediate layer 3.

<Heat shrinkage>
From the viewpoint of reducing the heat shrinkage in a high-temperature environment during heat welding and obtaining a molded article after joining as having better strength against shear stress parallel to the joining surface, the laminated film 10 of the present invention has a test temperature of 200. The upper limit of the heat shrinkage measured under the conditions of ° C. and a heating time of 10 minutes is preferably about 10% or less, more preferably about 3.0% or less, and further preferably about 2.8% or less. The lower limit is about 0% and about 0.1%. The range of the heat shrinkage is preferably about 0 to 10%, about 0 to 3.0%, about 0 to 2.8%, about 0 to 10%, and 0.1 to 3.0%. About 0.1 to 2.8%. The measurement of the heat shrinkage is performed by a method in accordance with JIS K 7133: 1999.

  In the present invention, at least two directions of the laminated film 10 in one direction (the plane direction of the laminated film 10) and the direction perpendicular thereto (the plane direction of the laminated film 10) satisfy the heat shrinkage ratio. preferable. One direction in which the heat shrinkage is measured and a direction perpendicular thereto are specifically, when the intermediate layer 3 of the laminated film 10 is a film, the direction corresponding to the MD of the intermediate layer 3 of the laminated film 10. Direction. In the present invention, the method for confirming the MD of the intermediate layer 3 of the laminated film 10 is as described in the tensile modulus of the intermediate layer 3 described later. When the intermediate layer 3 of the laminated film 10 is a fiber, the one direction may be the same direction as the MD of the first heat-welding resin layer 1 and the second heat-welding resin layer 2. The method of checking the MD of the first heat-welding resin layer 1 and the second heat-welding resin layer 2 is the same as the method of checking the MD of the intermediate layer 3.

<Shear strength>
Further, the shear strength of a molded article obtained by heat-welding the first member and the second member via the laminated film of the present invention is preferably about 10 MPa or more, more preferably about 11 MPa or more. The upper limit of the shear strength is not particularly limited, but is usually about 50 MPa or less. Preferred ranges of the shear strength include about 10 to 50 MPa and about 11 to 50 MPa. The shear strength is a value measured by the following measuring method. Since the shear strength when the laminated film 10 of the present invention for thermally welding the first member and the second member is thermally welded to these members is about 10 MPa or more, the obtained molded body is parallel to the joining surface. It can be said that it has excellent strength against shear stress. A molded body in which at least one of the first member and the second member has a thickness of 1 mm or more is susceptible to shear stress parallel to the joint surface, but has a shear strength of about 10 MPa or more, so that On the other hand, shear fracture is unlikely to occur, and the joined state can be favorably maintained. On the other hand, when the shear strength of the molded body in which at least one of the first member and the second member has a thickness of 1 mm or more is less than about 10 MPa, the shear fracture easily occurs with respect to the shear stress, and the bonding state is maintained well. It becomes difficult to do.

  The shear strength is measured by a method based on the provisions of ISO19095-2 and ISO19095-3. The sizes of the first member and the second member in the preparation of the test sample were 45 mm in length × 10 mm in width, and the thickness was 1.5 mm for a metal member, 3 mm for a ceramic member, and 3 mm for a resin member. 3 mm, and 3 mm for a fiber reinforced plastic member. The laminated film has a length of 5 mm and a width of 10 mm. As shown in FIG. 13, the laminated film 10 is disposed between the first member 70 and the second member 80 at the longitudinal ends of the first member 70 and the second member 80, and the temperature is 190 ° C. The first member 70 and the second member 80 are thermally welded via the laminated film 10 under the conditions of a surface pressure of 1.5 MPa and 20 seconds to obtain a molded body. Further, the entire surfaces of the laminated film 10 are arranged so as to be heat-sealed to the first member 70 and the second member 80, respectively (that is, the heat-sealing area is 5 mm long × 10 mm wide on one side). Although not shown in FIG. 13, the first member 70 and the second member 80 are connected to each other in a state where the first member 70 and the second member 80 are joined in parallel with each other. Each is joined by adjusting the height using a compensation member. The compensating member for adjusting the height of the first member 70 uses a member having the same material and shape as the first member 70, and the compensating member for adjusting the height of the second member 80 is the same material as the second member 80. A member having a shape is used. Next, using a tensile tester, the molded body was pulled in the length direction (tensile speed: 10 mm / min), the maximum load (N) was measured, and the heat load area (length 5 mm × width 10 mm) was measured. And calculate the shear strength (MPa).

<Seal strength>
In the laminated film 10 of the present invention, the seal strength between the laminated film and the member when the member (the first member and the second member) described later is thermally welded is preferably about 10 N / 15 mm or more. , More preferably about 15 N / 15 mm or more, even more preferably about 20 N / 15 mm or more. Although there is no particular upper limit of the seal strength, it is usually about 100 N / 15 mm or less. That is, the range of the sealing strength is preferably about 10 to 100 N / 15 mm, more preferably about 15 to 100 N / 15 mm, and still more preferably about 20 to 100 N / 15 mm. In the laminated film 10 of the present invention in which the first member and the second member are heat-welded, the resulting molded article has such a value that the seal strength when heat-welded to these members has such a value. Thus, it can be said that the first member and the second member are suitably joined via the laminated film 10 of the present invention. In the case where the first member and the second member when joined by heat welding are a molten resin and a solid member, the sealing strength when the laminated film 10 is thermally welded to the resin member obtained by cooling and solidifying the molten resin. Means In the case where at least one of the first member and the second member when joined by thermal welding is a solid member including an uncured resin, the laminated film 10 is thermally bonded to the member where the uncured resin is thermally cured. It means the sealing strength when welded. The specific method of measuring the seal strength is as follows. In addition, the sealing strength when the laminated film 10 of the present invention and the members (first and second members) described later are thermally welded is not limited to this range.

  In the measurement of the seal strength, first, the laminated film is cut into a size of 50 mm in the length direction (y direction) × 25 mm in the width direction (x direction). Next, the first heat-welding resin layer or the second heat-welding resin layer of the laminated film 10 and each member 50 are heat-sealed at a depth (y direction) of 7 mm (heat-sealing conditions: temperature 190 ° C., surface (Pressure 1 MPa, pressurization time 5 seconds) to obtain a test sample. In the schematic diagram of FIG. 6, a region S surrounded by a broken line indicates a heat-sealed region. A release sheet is sandwiched between portions other than the region to be heat-sealed, and heat-sealed at a depth of 7 mm. Next, the test sample is cut into a 15 mm width as shown in FIG. 6A so that the seal strength (N / 15 mm) in the width direction (x direction) of 15 mm can be measured. Next, as shown in FIG. 6B, the laminated film 10 is peeled from the fixed member 50 in the length direction (y direction) using a tensile tester. At this time, the peeling speed is 300 mm / min, and the maximum load until peeling is the seal strength (N / 15 mm). In addition, as a member in the preparation of the test sample, a resin member, a fiber reinforced plastic member, and a ceramic member having a thickness of 4 mm, and a metal member having a thickness of 0.5 mm are used. Each seal strength is an average value (n = 3) measured by preparing three test samples in the same manner.

<Peel strength>
The peel strength between the first member and the second member when the member (first member, second member) described later is thermally welded using the laminated film 10 of the present invention is about 10 N / 25 mm or more. Preferably, it is at least about 20 N / 25 mm, more preferably at least about 25 N / 25 mm. Although there is no particular upper limit of the peel strength, it is usually about 100 N / 25 mm or less. That is, the range of the peel strength is preferably about 10 to 100 N / 25 mm, more preferably about 20 to 100 N / 25 mm, and still more preferably about 25 to 100 N / 25 mm. The specific method of measuring the peel strength is as follows. The peel strength when the laminated film 10 of the present invention is thermally welded to the members (first and second members) described below is not limited to this range.

  The peel strength is measured by a method based on the provisions of ISO19095-2 and ISO19095-3. Specifically, first, the laminated film is cut into a size of 160 mm in the length direction × 25 mm in the width direction. In addition, the first member 70 (in the case where the thickness is different from the second member 80, for example, a thinner one such as metal) is 250 mm in the length direction × 25 mm in the width direction, and the second member 80 is 200 mm in the length direction. Cut out to a size of 25 mm in the width direction. Next, as shown in FIG. 16 (i), the first heat-welding resin layer or the second heat-welding resin layer of the laminated film 10 and the first member 70 and the second member 80 are overlapped in the longitudinal direction. A test sample is obtained by heat-sealing a region of 160 mm in the length direction × 25 mm in the width direction (heat sealing conditions: temperature 190 ° C., surface pressure 1 MPa, pressurization time 30 seconds). Next, the test sample is fixed to a peeling test jig on the second member 80 side, and the first member 70 is peeled in the length direction using a tensile tester as shown in FIG. 16 (ii). . At this time, the peeling speed is set to 100 mm / min, and the average load at a portion excluding the portion from the peeling start position to the peel length of 25 mm is defined as the peeling strength (N / 25 mm). In addition, as a member in the preparation of the test sample, a resin member, a fiber reinforced plastic member, and a ceramic member having a thickness of 4 mm, and a metal member having a thickness of 0.5 mm are used. Each peel strength is an average value (n = 3) measured by preparing three test samples in the same manner.

(First heat-welding resin layer 1)
In the present invention, the first heat-sealable resin layer 1 can constitute a surface on one side of the laminated film of the present invention. That is, the first heat-welding resin layer 1 can constitute the outermost layer on one side of the laminated film 10 of the present invention.

The heat-welding resin contained in the first heat-welding resin layer 1 is not particularly limited, but is preferably used from the viewpoint of suitably heat-welding not only a resin member but also an inorganic member such as a metal or a ceramic. Is a modified polyolefin (that is, having a polyolefin skeleton). The resin constituting the first heat-welding resin layer 1 may or may not contain a polyolefin skeleton, but preferably contains a polyolefin skeleton from the above viewpoint. The fact that the resin constituting the first heat-welding resin layer 1 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy or gas chromatography / mass spectrometry, and the analysis method is not particularly limited. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1.

  Further, the modified polyolefin is preferably an acid-modified polyolefin from the viewpoint of more suitably heat-welding not only resin members but also inorganic members such as metals and ceramics. Specific examples of the acid-modified polyolefin include a polyolefin modified with an unsaturated carboxylic acid or an anhydride thereof. Examples of the unsaturated carboxylic acid or anhydride thereof used for the acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like.

  When the modified polyolefin is acid-modified, the degree of acid modification is, for example, about 0.005% by weight as a lower limit from the viewpoint of more suitably heat-welding not only resin members but also inorganic members such as metals and ceramics. % Or more, from the viewpoint of more suitably heat-welding not only resin members but also inorganic members such as metals and ceramics, it is preferably about 0.01% by weight or more, and about 0.04% by weight. %, More preferably about 0.08% by weight or more. There is no particular upper limit for the degree of acid modification, but it is usually about 0.5% by weight or less. That is, the range of the degree of acid modification is, for example, about 0.005 to 0.5% by weight, preferably about 0.04 to 0.5% by weight, more preferably about 0.05 to 0.5% by weight, and furthermore Preferably, about 0.08 to 0.5% by weight is used. Furthermore, since the laminated film of the present invention can improve the strength against shear stress parallel to the joining surface in the molded article after joining, even if the upper limit of the degree of acid modification is, for example, about 0.13% by weight or less, the joining can be performed. The strength against shear stress parallel to the plane can be effectively improved. From such a viewpoint, the range of the acid modification degree is, for example, about 0.005 to 0.13%, preferably about 0.04 to 0.13% by weight, and more preferably 0.05 to 0.13% by weight. Level, more preferably about 0.08 to 0.13% by weight.

The degree of acid modification is the weight ratio of the acid-modified group in the acid-modified polyolefin. For example, in the case of a maleic acid-modified polyolefin, it is the weight ratio of the maleic acid-modified group in the acid-modified polyolefin. The acid modification degree is determined from a value quantified from an acid-derived peak area in ¹ H-NMR. Specifically, first, to measure a ¹ H-NMR of the _{ODCB-d4 / C 6 D 6} ( volume ratio 4/1) ¹ H-NMR and methyl esters of the acid-modified polyolefin of the acid-modified polyolefin in a solvent . By comparing both ¹ H-NMRs, the peak of the methyl esterified product from which the acid has been derivatized is identified. Further, from the ¹ H-NMR of the acid-modified polyolefin (before methyl esterification), the area of the impurity-derived peak overlapping at the peak position of the methyl ester in the ¹ H-NMR of the methyl ester is specified. By subtracting the peak area derived from impurities from the peak area at the peak position of the methyl esterified product, the peak area of the methyl esterified product is obtained, and the mass of the acid-modified group derived based on this and the mass of the acid-modified polyolefin before methyl esterification are determined. The degree of acid modification is calculated from the ratio with the mass.

  The polyolefin to be modified is not particularly limited, but is preferably a low-density polyethylene, a medium-density polyethylene, a high-density polyethylene, a linear low-density polyethylene, from the viewpoint of suitably performing heat welding to inorganic members such as metals and ceramics. Polyethylene, such as high density polyethylene; crystalline or amorphous polypropylene, such as homopolypropylene, block copolymer of polypropylene (eg, block copolymer of propylene and ethylene), random copolymer of polypropylene (eg, random copolymer of propylene and ethylene); ethylene -Butene-propylene terpolymers. Among these, polypropylene is preferable as the polyolefin to be modified.

  From the viewpoint of suitably performing heat welding to inorganic members such as metals and ceramics, among the heat-welding resins contained in the first heat-welding resin layer 1, particularly maleic anhydride-modified polypropylene and maleic anhydride-modified Modified polyolefins such as polyethylene are preferred.

  One kind of the heat-welding resin included in the first heat-welding resin layer 1 may be used, or two or more kinds thereof may be used.

  The ratio of the heat-welding resin contained in the first heat-welding resin layer 1 is not particularly limited, but the lower limit is preferably about 70% by mass or more, more preferably about 80% by mass or more, and the upper limit. Preferably, about 100% by mass or less. The range of the ratio of the heat-welding resin is preferably about 70 to 100% by mass, and about 80 to 100% by mass. Since the ratio of the heat-welding resin contained in the first heat-welding resin layer 1 has such a value, the laminated film 10 of the present invention can suitably exhibit the heat-welding property, Two or more members can be more preferably thermally welded.

  The first heat-welding resin layer 1 may further contain an adhesive component as long as the strength of the molded article after joining does not affect the strength against shear stress parallel to the joining surface. More specifically, the first heat-welding resin layer 1 may be made of a heat-welding resin composition containing an adhesive component. Since the first heat-welding resin layer 1 contains an adhesive component, the first heat-welding resin layer of the laminated film can be suitably temporarily adhered to the first member or the second member, and the misalignment at the time of heat welding can be achieved. Thus, it is possible to more suitably heat-bond two or more members. In the present invention, the term “temporary attachment” means to temporarily adhere, and is a state in which it can be peeled off even after temporarily attached.

  The adhesive component is not particularly limited as long as it can impart adhesiveness to the first heat-welding resin layer 1, and for example, rosin such as rosin, hydrogenated rosin, polymerized rosin, rosin ester or a derivative thereof; α- Terpene resins such as pinene, β-pinene, limonene; terpene phenol resins, cumarone / indene resins, styrene resins, xylene resins, phenol resins, petroleum resins, hydrogenated petroleum resins, and the like. Further, an amorphous polyolefin can be used as the adhesive component. Examples of the amorphous polyolefin include amorphous polypropylene or a copolymer of amorphous propylene and another α-olefin, and specific examples thereof include propylene / ethylene copolymer, propylene / butene-1 copolymer, and propylene. -Butene-1-ethylene-terpolymer, propylene-hexene-1-octene-terpolymer, propylene-hexene-1-4-methylpentene-terpolymer, propylene-hexene -1,4-methylpentene-1 / 3 terpolymer, polybutene-1 and the like. One kind of the adhesive component may be used alone, or two or more kinds may be used in combination.

  When the first heat-welding resin layer 1 contains an adhesive component, the ratio of the adhesive component is not particularly limited, but the lower limit is preferably about 1% by mass or more, more preferably about 5% by mass or more. The upper limit is preferably about 30% by mass or less, more preferably about 25% by mass or less. The range of the ratio of the adhesive component is preferably about 1 to 30% by mass, about 1 to 25% by mass, about 5 to 30% by mass, and about 5 to 25% by mass. Since the ratio of the adhesive component contained in the first heat-welding resin layer 1 has such a value, the laminated film of the present invention suitably exhibits excellent adhesiveness and excellent heat-welding property. Thus, two or more members can be more appropriately thermally welded. In particular, when at least one member is a solid member, the first heat-sealable resin layer of the laminated film can be preferably temporarily adhered to the solid member, and the displacement during the heat welding can be suppressed. It is possible to more suitably heat-bond two or more members.

  The melt mass flow rate (MFR) of the first heat-welding resin layer 1 is not particularly limited, but from the viewpoint of improving the followability to the surface of the member and making the two or more members more suitable for heat welding, the lower limit is set. Preferably, it is about 2 g / 10 min or more, more preferably about 4 g / 10 min or more. From the viewpoint of preventing the outflow of the resin melted at the time of heat welding and more suitably heat-sealing the two or more members, the preferable upper limit of the melt mass flow rate (MFR) of the first heat-weldable resin layer 1 is preferable. Is about 20 g / 10 min or less, more preferably about 15 g / 10 min or less, even more preferably about 10 g / 10 min or less. That is, the range of the melt flow rate is preferably about 2 to 20 g / 10 min, more preferably about 4 to 20 g / 10 min, still more preferably about 4 to 15 g / 10 min, and further preferably 4 to 10 g / min. About 10 minutes. The melt mass flow rate (MFR) is a value measured using a melt indexer by applying a measuring temperature of 230 ° C. and a load of 2.16 kg by a method in accordance with JIS K7210: 2014.

  The softening point of the first heat-welding resin layer 1 is not particularly limited, but is preferably about 180 ° C. from the viewpoint of improving the followability to the surface of the member and making the two or more members more heat-sealed. Or less, more preferably about 160 ° C. or less. The lower limit of the softening point of the first heat-welding resin layer 1 is, for example, about 80 ° C. or higher, preferably 100 ° C. or higher. Preferred ranges of the softening point of the first heat-welding resin layer 1 are about 80 to 180 ° C, about 80 to 160 ° C, about 100 to 180 ° C, and about 100 to 160 ° C.

  In the present invention, the softening point of the first heat-welding resin layer 1 is the temperature at which the deflection of the probe becomes maximum in the subsequent measurement of the displacement of the probe. In the measurement of the softening point of the first heat-welding resin layer 1, the temperature at which the deflection of the probe becomes maximum is read for five samples of the first heat-welding resin layer 1 to be measured. The average value of the three temperatures excluding the maximum value and the minimum value of the five temperatures is defined as a softening point. In measuring the displacement of the probe, first, as shown in the conceptual diagram of FIG. 14, for example, the position of the end of the laminated film on the surface of the first heat-welding resin layer 1 (for example, in the laminated film 10 of FIG. 15). In the case of the heat-welding resin layer 1, the probe 90 is installed at the position P (measurement start A in FIG. 14). The end portion at this time is a portion where the cross section of the first heat-welding resin layer 1 is obtained by cutting in the thickness direction so as to pass through the center portion of the laminated film. Cutting can be performed using a commercially available rotary microtome or the like. An atomic force microscope equipped with a nanothermal microscope composed of a cantilever with a heating mechanism, for example, an afm plus system manufactured by ANASIS INSTRUMENTS is used, and a probe manufactured by ANASYS INSTRUMENTS can be used. The tip radius of the probe is 30 nm or less, the set value of the deflection of the probe is -4 V, and the heating rate is 5 ° C./min. Next, when the probe is heated in this state, the surface of the first heat-welding resin layer 1 expands due to the heat from the probe 90 as shown in FIG. Rises from the initial value (the position when the temperature of the probe 90 is 40 ° C.). When the heating temperature further rises, the first heat-welding resin layer 1 is softened, and the probe 90 may pierce the first heat-welding resin layer 1 as shown in FIG. . In the measurement of the displacement of the probe 90 using an atomic force microscope equipped with a nanothermal microscope composed of a cantilever with a heating mechanism, the laminated film to be measured is in a room temperature (25 ° C.) environment and is at 40 ° C. The heated probe 90 is placed on the surface of the first heat-fusible resin layer 1 at the end of the laminated film, and the measurement is started.

  Although the thickness of the first heat-welding resin layer 1 is not particularly limited, the heat-shrinkage rate in a high-temperature environment at the time of heat welding is reduced, and the joined compact is more excellent in strength against shear stress parallel to the joining surface. From the viewpoint of obtaining the lower limit, the lower limit is preferably about 5 μm or more, more preferably about 10 μm or more, further preferably about 20 μm or more, and the upper limit is preferably about 200 μm or less, more preferably about 100 μm or less. And more preferably about 50 μm or less. The thickness of the first heat-welding resin layer 1 is preferably in the range of about 5 to 200 μm, about 5 to 100 μm, about 5 to 50 μm, about 10 to 200 μm, about 10 to 100 μm, about 10 to 50 μm. About 20 to 200 μm, about 20 to 100 μm, and about 20 to 50 μm.

  The material, softening point, thickness, and the like of the first heat-welding resin layer 1 and a second heat-welding resin layer 2 described later may be the same or different.

(Mid layer 3)
In the present invention, the intermediate layer 3 is located between the first heat-welding resin layer 1 and the second heat-welding resin layer 2, and can ensure an excellent high tensile modulus of the laminated film 10. it can.

  The material constituting the intermediate layer 3 is not particularly limited as long as it has a high tensile modulus, and examples thereof include polyester, polyimide, polyamide, epoxy resin, polyvinyl alcohol, polyphenylene sulfide, polyarylate, polycarbonate, acrylic resin, and fluororesin. , A silicone resin, a phenol resin, a polyetherimide, and mixtures and copolymers thereof.

  As the polyester, specifically, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolymerized polyester having ethylene terephthalate as the main unit of the repeating unit, and butylene terephthalate as the main unit of the repeating unit And the like. Examples of the copolymerized polyester mainly composed of ethylene terephthalate as a repeating unit include copolymer polyesters (hereinafter referred to as polyethylene (terephthalate / isophthalate)) which polymerize ethylene terephthalate as a repeating unit mainly and polymerize with ethylene isophthalate. , Polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate) And polyethylene (terephthalate / decanedicarboxylate) and the like. As the copolymerized polyester mainly composed of butylene terephthalate as a repeating unit, specifically, a copolymer polyester mainly composed of butylene terephthalate as a repeating unit and polymerized with butylene isophthalate (hereinafter referred to as polybutylene (terephthalate / isophthalate)) ), Polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene naphthalate, and the like. These polyesters may be used alone or in a combination of two or more.

  As the polyester, in addition to the above, an aromatic polyester which is a polycondensate containing a monomer selected from the group consisting of an aromatic diol, an aromatic dicarboxylic acid, and an aromatic hydroxycarboxylic acid at an arbitrary composition ratio is also included. Among the aromatic polyesters, a wholly aromatic polyester having no aliphatic hydrocarbon in the main chain is preferable. Specific examples of the wholly aromatic polyester include a copolymer of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, a copolymer of p-hydroxybenzoic acid and terephthalic acid and 4,4′-dihydroxybisphenyl, and the like. Of polyarylate.

  From the viewpoint of reducing the heat shrinkage in a high-temperature environment at the time of heat welding and making the laminated film 10 have a higher tensile modulus, among these, the material of the intermediate layer 3 is preferably polyethylene terephthalate, polyethylene naphthalate, or the like. Examples include wholly aromatic polyester, polyimide, polyphenylene sulfide, aramid, and vinylon (polyvinyl alcohol). These resins may be used alone or in a combination of two or more.

  The form of the intermediate layer 3 is not particularly limited, and examples thereof include a film and a fiber. As a specific form of the fiber, a nonwoven fabric is preferable. From the viewpoint of obtaining a higher tensile modulus of the laminated film 10, the intermediate layer 3 is preferably a film.

  When the intermediate layer 3 is a film, the intermediate layer 3 is preferably made of a polyethylene terephthalate film, a polyethylene naphthalate film, or a polyimide film.

  When the intermediate layer 3 is a fiber, the intermediate layer 3 is preferably made of a polyphenylene sulfide fiber, an aramid fiber, a vinylon (polyvinyl alcohol) fiber, or a wholly aromatic polyester fiber.

  Among these fibers, the wholly aromatic polyester fiber has a molecular orientation (melt anisotropy) in a molten state of the wholly aromatic polyester, and is a fiber obtained by spinning the fiber (melt anisotropic wholly aromatic polyester fiber). However, since the molecular orientation is further advanced, the fibers are easily entangled with each other, so that not only is the nonwoven fabric excellent in mechanical strength and low in hygroscopicity, but also easy to penetrate the resin into the divided and subdivided gaps and excellent in resin impregnation. Therefore, it is preferable in that the interlayer strength of the laminated film 10 is extremely high. Therefore, among the wholly aromatic polyester fibers, a nonwoven fabric made of the melt-anisotropic wholly aromatic polyester fibers is most preferable.

  The lower limit of the tensile elastic modulus of the intermediate layer 3 is approximately from the viewpoint of setting the laminated film 10 to a specific tensile elastic modulus and obtaining a molded article after joining as having excellent strength against shear stress parallel to the joining surface. It is preferably 1500 MPa or more, more preferably about 2000 MPa or more, further preferably about 2900 MPa or more, and particularly preferably about 5000 MPa or more. Although there is no particular upper limit of the tensile modulus, it is usually about 10,000 MPa or less, preferably about 8000 MPa or less, and more preferably 7000 MPa or less. That is, the range of the tensile elastic modulus is about 1500 to 10000 MPa, about 1500 to 8000 MPa, about 1500 to 7000 MPa, about 2000 to 10000 MPa, about 2000 to 8000 MPa, about 2000 to 7000 MPa, about 2900 to 10000 MPa, about 2900 to 8000 MPa. About 2,900 to 7000 MPa, about 5,000 to 10,000 MPa, about 5,000 to 8,000 MPa, and about 5,000 to 7000 MPa. The tensile modulus of the intermediate layer 3 is a value obtained by measuring the material constituting the intermediate layer 3 in accordance with JIS K7161: 2014.

  A specific measuring method measured in accordance with JIS K7161: 2014 is as described in the tensile modulus of the laminated film 10 described above. In the preparation of a test piece for use in measuring the tensile modulus, a method for confirming the MD of the intermediate layer 3 is as follows. The angle of the cross section in the length direction of the laminated film 10 and the angle parallel to the cross section in the length direction are changed by 10 degrees each, and each cross section up to a direction perpendicular to the cross section in the length direction (10 cross sections in total). Each of the intermediate layers 3 is observed with a transmission electron micrograph to confirm the sea-island structure. Next, in each cross section, the shape of each island of the intermediate layer 3 is observed. Regarding the shape of each island, the straight line distance connecting the leftmost end in the vertical direction with respect to the thickness direction of the laminated film 10 and the rightmost end in the vertical direction is defined as a diameter y. In each section, the average of the top 20 diameters y is calculated in descending order of the diameter y of the island shape. The direction parallel to the cross section where the average of the diameter y of the island shape is the largest is determined to be MD. When the intermediate layer 3 of the laminated film 10 is a fiber, the MD may be determined based on the roll direction of the fiber material constituting the intermediate layer 3. However, when the MD cannot be specified, any MD may be used. What is necessary is just to produce a test piece so that a direction may become a long side.

  The heat shrinkage of the intermediate layer 3 measured under the conditions of a test temperature of 200 ° C. and a heating time of 10 minutes reduces the heat shrinkage in a high-temperature environment at the time of heat welding, and causes the molded body after joining to be parallel to the joining surface. From the viewpoint of obtaining superior strength against shear stress, the upper limit is preferably about 10% or less, more preferably about 5% or less, still more preferably about 3% or less, and particularly preferably 2% or less. The lower limit is about 0% or more and about 0.1% or more. The range of the heat shrinkage is about 0 to 10%, about 0 to 5%, about 0 to 3%, about 0 to 2%, about 0.1 to 10%, about 0.1 to 5%, About 0.1 to 3%, and about 0.1 to 2%. The measurement of the heat shrinkage can be performed by a method in accordance with JIS K 7133: 1999.

  In the present invention, the heat shrinkage ratio is satisfied in at least two directions, one direction of the intermediate layer 3 (the plane direction of the intermediate layer 3) and the direction perpendicular to the one direction (the plane direction of the intermediate layer 3). preferable. One direction in which the heat shrinkage is measured and a direction perpendicular thereto are, specifically, the MD of the intermediate layer 3 when the intermediate layer 3 is a film. In the present invention, the method of confirming the MD of the intermediate layer 3 of the laminated film 10 is as described in the tensile modulus of the intermediate layer 3 described above. When the MD cannot be specified when the intermediate layer 3 of the laminated film 10 is a fiber, an arbitrary direction may be set as the one direction.

  The melting peak temperature of the intermediate layer 3 is not particularly limited, but from the viewpoint of further improving heat resistance, the melting peak temperature of the intermediate layer 3 is preferably about 200 ° C. or higher, more preferably about 230 ° C. or higher. Preferably, about 240 ° C. or higher is used. The upper limit of the melting peak temperature of the intermediate layer 3 is not particularly limited, but may be, for example, about 300 ° C. or less. The preferred range of the melting peak temperature of the intermediate layer 3 is preferably about 200 to 300 ° C, more preferably about 230 to 300 ° C, and further preferably about 240 to 300 ° C. In the present invention, the melting peak temperature is a value measured using a differential scanning calorimeter (DSC), the rate of temperature rise is 10 ° C./min, the temperature measurement range is 100 to 350 ° C., and an aluminum pan is used as a sample pan. Measured using

  The thickness of the intermediate layer 3 is not particularly limited, but the viewpoint is to reduce the heat shrinkage in a high-temperature environment at the time of heat welding and to obtain a molded article having excellent strength against shear stress parallel to the bonding surface after bonding. Therefore, the lower limit is preferably about 5 μm or more, more preferably about 10 μm or more, and the upper limit is preferably about 200 μm or less, more preferably about 100 μm or less, and still more preferably about 50 μm or less. The thickness of the intermediate layer 3 is preferably about 5 to 200 μm, about 5 to 100 μm, about 5 to 50 μm, about 10 to 200 μm, about 10 to 100 μm, or about 10 to 15 μm. Further, when the intermediate layer 3 is a film, the thickness of the intermediate layer 3 may be, as an upper limit, preferably about 30 μm or less, more preferably about 20 μm or less. When the intermediate layer 3 is a film, the thickness of the intermediate layer 3 may be about 5 to 30 μm, about 10 to 30 μm, about 5 to 20 μm, or about 10 to 20 μm.

When the intermediate layer 3 is made of a non-woven fabric, the basis weight of the non-woven fabric is not particularly limited, but may be a layer adjacent to the intermediate layer 3 (for example, the first heat-welding resin layer 1, the second heat-sealing resin). From the viewpoint of sufficiently impregnating the nonwoven fabric with the layer 2 and the thermoplastic resin layer 4) to stabilize the adhesive strength between the layers, the basis weight is preferably small, and the lower limit is preferably about 5 g / m ² or more. Can be From the viewpoint of reducing the thermal shrinkage in a high-temperature environment during thermal welding, the basis weight is preferably large, and the upper limit is 30 g / m ² or less. From the viewpoint of reducing the heat shrinkage in a high-temperature environment at the time of thermal welding and improving the appearance after thermal welding and more suitably performing thermal welding of two or more members, the range of the basis weight is preferably 5 to 30 g / m ^2, more preferably about include about 7~25g / m ^2.

(Second heat-welding resin layer 2)
In the present invention, the second heat-welding resin layer 2 is a layer located on the opposite side of the intermediate layer 3 from the first heat-welding resin layer 1. The second heat-welding resin layer 2 is made of a heat-welding resin composition.

The heat-welding resin contained in the second heat-welding resin layer 2 is not particularly limited, but is preferably heat-sealed not only to inorganic members such as metals and ceramics, but also to resin members, particularly fiber-reinforced plastics. From the viewpoint, preferably, a modified polyolefin (that is, having a polyolefin skeleton) is used. That is, the resin constituting the second heat-welding resin layer 2 may not include the polyolefin skeleton, but preferably includes the polyolefin skeleton from the above viewpoint. The fact that the resin constituting the second heat-welding resin layer 2 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography / mass spectrometry, etc., and the analysis method is not particularly limited. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1.

  The modified polyolefin is preferably an acid-modified polyolefin, particularly from the viewpoint of suitably heat-welding the fiber-reinforced plastic. Specific examples of the acid-modified polyolefin include a polyolefin modified with an unsaturated carboxylic acid or an anhydride thereof. Examples of the unsaturated carboxylic acid or anhydride thereof used for the acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like.

When the modified polyolefin is acid-modified, the lower limit of the degree of acid modification is preferably about 0.01% by weight or more, and more preferably about 0.1% by weight, particularly from the viewpoint of suitably welding to fiber-reinforced plastics. It is more preferably at least 06% by weight, even more preferably at least about 0.08% by weight. There is no particular upper limit for the degree of acid modification, but it is usually about 0.5% by weight or less. That is, the range of the degree of acid modification is preferably about 0.01 to 0.5% by weight, more preferably about 0.06 to 0.5% by weight, and still more preferably about 0.08 to 0.5% by weight. Is mentioned. The degree of acid modification is a weight ratio of an acid-modified group in an acid-modified polyolefin. For example, in the case of a maleic acid-modified polyolefin, it is the weight ratio of the maleic acid-modified group in the acid-modified polyolefin. The acid modification degree is quantified from an acid-derived peak area of ¹ H-NMR. Specifically, first, to measure a ¹ H-NMR of the _{ODCB-d4 / C 6 D 6} ( volume ratio 4/1) ¹ H-NMR and methyl esters of the acid-modified polyolefin of the acid-modified polyolefin in a solvent . By comparing both ¹ H-NMRs, the peak of the methyl esterified product from which the acid has been derivatized is identified. Further, from the ¹ H-NMR of the acid-modified polyolefin (before methyl esterification), the area of the impurity-derived peak overlapping at the peak position of the methyl ester in the ¹ H-NMR of the methyl ester is specified. By subtracting the peak area derived from impurities from the peak area at the peak position of the methyl esterified product, the peak area of the methyl esterified product is obtained, and the mass of the acid-modified group derived based on this and the mass of the acid-modified polyolefin before methyl esterification are determined. The degree of acid modification is calculated from the ratio with the mass.

  The polyolefin to be modified is not particularly limited, but from the viewpoint of suitably heat-sealing the fiber-reinforced plastic, preferably, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, etc. Crystalline or amorphous polypropylene such as homopolypropylene, block copolymer of polypropylene (for example, block copolymer of propylene and ethylene), and random copolymer of polypropylene (for example, random copolymer of propylene and ethylene); ethylene-butene- And terpolymers of propylene. Among these, polypropylene is preferable as the polyolefin to be modified.

  In particular, from the viewpoint of suitably performing the heat welding to the fiber reinforced plastic, among the heat welding resins contained in the second heat welding resin layer 2, maleic anhydride-modified polypropylene is particularly preferable.

  The heat-welding resin contained in the second heat-welding resin layer 2 may be one kind or two or more kinds.

  The proportion of the heat-welding resin contained in the second heat-welding resin layer 2 is not particularly limited, but the lower limit is preferably about 70% by mass or more, more preferably about 80% by mass or more, and the upper limit. Preferably, about 100% by mass or less. The range of the ratio of the heat-welding resin is preferably about 70 to 100% by mass, and about 80 to 100% by mass. Since the ratio of the heat-welding resin contained in the second heat-welding resin layer 2 has such a value, the laminated film 10 of the present invention can suitably exhibit heat-welding properties, Two or more members can be more preferably thermally welded.

  The second heat-welding resin layer 2 may contain an adhesive component in the molded article after the joining, as long as the strength against shear stress parallel to the joining surface is not affected. When the second heat-welding resin layer 2 contains an adhesive component, the second heat-welding resin layer 2 can exhibit adhesiveness similarly to the first heat-welding resin layer 1. When the first heat-sealing resin layer 1 and the second heat-sealing resin layer 2 contain an adhesive component, the first heat-sealing resin layer 1 and the second heat-sealing resin layer 2 of the laminated film 10 are used. Can be temporarily attached to the solid member. For this reason, misalignment or the like when two or more solid members are thermally welded is suppressed, and the two or more solid members can be suitably thermally welded.

  When the second heat-welding resin layer 2 contains an adhesive component, the type and content of the adhesive component are not particularly limited, and the same ones as those exemplified for the first heat-welding resin layer 1 are exemplified. Is done.

  Although the melt mass flow rate (MFR) of the second heat-welding resin layer 2 is not particularly limited, two or more members are more preferably formed by improving the followability of the surface of the member, particularly the uneven surface of the fiber-reinforced plastic. From the viewpoint of heat welding, the lower limit is preferably about 2 g / 10 min or more, more preferably about 4 g / 10 min or more. In particular, when the fiber-reinforced resin plastic is thermally welded, the second heat-weldable resin layer 2 follows the surface unevenness well even if the surface unevenness (surface roughness Ra) of the fiber-reinforced resin plastic increases, and the anchoring is performed. From the viewpoint that the effect is effectively obtained and the second member is suitably thermally welded to the second member, the melt mass flow rate (MFR) of the second thermally weldable resin layer 2 is preferably about 4 g / 10 minutes or more. From the viewpoint of preventing the outflow of the resin melted during the heat welding and more suitably performing the heat welding of two or more members, the preferable upper limit of the melt mass flow rate (MFR) of the second heat-welding resin layer 2 is preferably Is about 20 g / 10 min or less, more preferably about 15 g / 10 min or less. That is, the range of the melt flow rate is preferably about 2 to 20 g / 10 minutes, more preferably about 4 to 20 g / 10 minutes, and still more preferably about 4 to 15 g / 10 minutes. The melt mass flow rate (MFR) is a value measured using a melt indexer by applying a measuring temperature of 230 ° C. and a load of 2.16 kg by a method in accordance with JIS K7210: 2014.

  The softening point of the second heat-welding resin layer 2 is not particularly limited, but is preferably about 180 from the viewpoint of improving the followability to the surface of the heat member and making the two or more members more heat-sealed. ℃ or lower, more preferably about 160 ℃ or lower. The lower limit of the softening point of the second heat-welding resin layer 2 is, for example, about 80 ° C. or more, preferably about 100 ° C. or more. Preferred ranges of the softening point of the second heat-welding resin layer 2 include about 80 to 180 ° C, about 80 to 160 ° C, about 100 to 180 ° C, and about 100 to 160 ° C. In the present invention, the softening point of the second heat-welding resin layer 2 is a value measured in the same manner as the softening point of the first heat-welding resin layer 1 described above.

  Although the thickness of the second heat-welding resin layer 2 is not particularly limited, the heat-shrinkage rate in a high-temperature environment during heat welding is reduced, and the molded body after joining is more excellent in strength against shear stress parallel to the joining surface. From the viewpoint of obtaining the lower limit, the lower limit is preferably about 5 μm or more, more preferably about 10 μm or more, further preferably about 20 μm or more, and the upper limit is preferably about 200 μm or less, more preferably about 100 μm or less. And more preferably about 50 μm or less. The thickness of the second heat-welding resin layer 2 is preferably about 5 to 200 μm, about 5 to 100 μm, about 5 to 50 μm, about 10 to 200 μm, about 10 to 100 μm, about 10 to 50 μm. About 20 to 200 μm, about 20 to 100 μm, and about 20 to 50 μm.

(Thermoplastic resin layer 4)
In the present invention, the thermoplastic resin layer 4 is a layer that is laminated on the laminated film 10 as necessary. It is preferable that the thermoplastic resin layer 4 is laminated between the first heat-welding resin layer 1 and the intermediate layer 3 and between the intermediate layer 3 and the second heat-welding resin layer 2. One layer of the thermoplastic resin layer 4 may be laminated on the laminated film 10, or two or more layers may be laminated. The number of layers of the thermoplastic resin layer 4 in the laminated film 10 is preferably about 0 to 2, more preferably about 0 to 1. When at least one of the first heat-welding resin layer 1 and the second heat-welding resin layer 2 contains an adhesive component, a layer containing the adhesive component is laminated on the intermediate layer 3 via the thermoplastic resin layer 4. This makes it possible to stabilize the adhesive strength between the layers. Therefore, for example, the first heat-welding resin layer 1 and the second heat-welding resin layer 2 constitute both surfaces of the laminated film 10, and the first heat-welding resin layer 1 and the second heat-welding resin layer 2 When the adhesive component is included, the thermoplastic resin layer 4 is formed between the first heat-welding resin layer 1 and the intermediate layer 3 and between the intermediate layer 3 and the second heat It is preferable that the layers are laminated one by one with the weldable resin layer 2. Further, for example, when the first heat-welding resin layer 1 constitutes one side of the laminated film 10 and the first heat-welding resin layer 1 contains an adhesive component, as shown in FIG. It is preferable that one thermoplastic resin layer 4 is laminated between the first heat-welding resin layer 1 and the intermediate layer 3.

The thermoplastic resin constituting the thermoplastic resin layer 4 is not particularly limited as long as it has thermoplasticity. Examples of the thermoplastic resin include polyolefin, polyester, polyamide, acrylic resin, fluororesin, and silicone resin. Among these, the thermoplastic resin layer 4 is preferably composed of a polyolefin, and more preferably composed of a modified polyolefin (that is, having a polyolefin skeleton). As the modified polyolefin, those same as those exemplified in the first heat-welding resin layer 1 are preferably exemplified. That is, the resin constituting the thermoplastic resin layer 4 may or may not contain the polyolefin skeleton, but preferably contains the polyolefin skeleton from the above viewpoint. A thermoplastic resin having a polyolefin skeleton is preferable as the thermoplastic resin contained in the thermoplastic resin layer 4 because of its excellent solvent resistance. The fact that the resin constituting the thermoplastic resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy or gas chromatography / mass spectrometry, and the analysis method is not particularly limited. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1.

  The thermoplastic resin layer 4 may contain an adhesive component as long as the strength of the molded article after joining does not affect the strength against shear stress parallel to the joining surface. When the thermoplastic resin layer 4 contains an adhesive component, the thermoplastic resin layer 4 can exhibit adhesiveness. When the thermoplastic resin layer 4 contains an adhesive component, the type of the adhesive component is not particularly limited, and examples thereof include the same as those exemplified for the first heat-welding resin layer 1. The ratio of the adhesive component in the thermoplastic resin layer 4 is not particularly limited, and may be the same ratio as that of the first heat-welding resin layer 1.

(Other layers)
In the laminated film 10 of the present invention, other layers different from the first heat-welding resin layer 1, the second heat-welding resin layer 2, the intermediate layer 3, and the thermoplastic resin layer 4 may be further laminated. Good.

(Additive)
The laminated film 10 of the present invention may contain various additives such as a lubricant, an antioxidant, an ultraviolet absorber, and a light stabilizer as needed. In addition, as a additive, the kind and content with which the laminated film 10 does not change color are suitably selected by those skilled in the art.

(Production method of laminated film)
The laminated film 10 of the present invention laminates at least the first heat-welding resin layer 1, the intermediate layer 3, the second heat-welding resin layer 2, and the thermoplastic resin layer 4 provided as necessary. It can be manufactured by the following. The method for laminating these layers is not particularly limited, and for example, the lamination can be performed using a thermal lamination method, a sandwich lamination method, an extrusion lamination method, or the like.

  Further, in the laminated film 10 of the present invention, when the intermediate layer 3 is formed of a resin film, the intermediate layer 3 is adjacent by applying an adhesion promoter to both surfaces of the intermediate layer 3 (that is, providing an adhesion promoter layer). The adhesion strength with the layers (for example, the first heat-welding resin layer 1, the second heat-welding resin layer 2, the thermoplastic resin layer 4, etc.) can be improved, and the laminated structure can be stabilized. Further, the surface of the intermediate layer 3 may be provided with a known easy adhesion means such as a corona discharge treatment, an ozone treatment, and a plasma treatment, if necessary.

  As the adhesion promoter for forming the adhesion promoter layer, known adhesion promoters such as isocyanate-based, polyethyleneimine-based, polyester-based, polyurethane-based, and polybutadiene-based can be used. Further, the adhesion promoter layer can also be formed using a known adhesive such as a two-part curable adhesive or a one-part curable adhesive.

  The adhesion promoter layer can be provided on one side or both sides of the intermediate layer 3. The adhesion promoter layer can be formed by applying and drying by a known coating method such as a bar coating method, a roll coating method, and a gravure coating method.

(Element)
The materials of the first member and the second member joined by the laminated film 10 are not particularly limited, and examples thereof include a resin, a fiber-reinforced plastic, and an inorganic substance (eg, metal, ceramics, and the like).

  When the material constituting the member is a resin, specific examples include polyolefin, polyester, polyamide, epoxy resin, acrylic resin, fluororesin, silicone resin, ABS resin and the like. Among these, polyethylene, polypropylene and the like Preferred are polyolefin, epoxy resin, ABS resin and the like.

  When the material constituting the member is a fiber-reinforced plastic, the fiber-reinforced plastic may be a composite material whose strength is improved by including fibers in a matrix resin. Examples of the matrix resin of the fiber-reinforced plastic include a thermosetting resin (a cured product of a thermosetting resin) and a thermoplastic resin, and more preferably a thermosetting resin (a cured product of a thermosetting resin). The laminated film of the present invention can improve the strength against shear stress parallel to the joint surface in the molded article after joining. Therefore, as a matrix resin of the fiber-reinforced plastic, a thermosetting resin (thermosetting (Cured resin)), the strength against shear stress parallel to the joint surface can be effectively improved.

  Examples of the thermosetting resin used as the matrix resin of the fiber-reinforced plastic include an epoxy resin, an unsaturated polyester resin, a phenol resin, a silicone resin, a urethane resin, and a polyimide resin, and preferably an epoxy resin. These thermosetting resins can be used alone or in combination of two or more. Examples of the thermoplastic resin used as the matrix resin of the fiber-reinforced plastic include polysulfone, polyether sulfone, polyetherimide, polyimide, various thermoplastic elastomers, and the like. These thermoplastic resins can be used alone or in combination of two or more.

  The fiber of the fiber reinforced plastic is not particularly limited, and examples thereof include inorganic fibers such as carbon fiber and glass fiber, and organic fibers such as aramid fiber. Among these, carbon fibers and glass fibers are preferred, and carbon fibers are more preferred, from the viewpoint of obtaining a molded article after bonding as having better strength against shear stress parallel to the bonding surface. The carbon fiber is not particularly limited, and may be any of a polyacrylonitrile (PAN) type, a pitch type, and the like, or a mixture of them. The weave of the fibers may be any of long fibers aligned in one direction, bidirectional fabrics, multiaxial fabrics, nonwoven fabrics, mats, knits, braids, and the like. The term “long fiber” as used herein means a single fiber or a fiber bundle substantially continuous for 10 mm or more.

  The surface roughness Ra of the fiber reinforced plastic is, for example, about 1 μm or more. The surface roughness Ra is about 3 μm or more from the viewpoint of obtaining an anchor effect by the heat-welding resin layer 1 of the laminated film 10 of the present invention following the surface irregularities more effectively and bonding more appropriately. And more preferably about 8 μm or more. The upper limit of the surface roughness Ra is not particularly limited, but is, for example, about 100 μm or less from the viewpoint of easily following the heat-welding resin layer of the laminated film to the surface irregularities. That is, the range of the surface roughness Ra is, for example, about 1 to 100 μm, preferably about 3 to 100 μm, and more preferably about 8 to 100 μm. Furthermore, since the laminated film of the present invention can improve the strength against shear stress parallel to the joining surface in the molded article after joining, the upper limit of the surface roughness Ra is, for example, about 70 μm or less, preferably about 30 μm or less, more preferably Even when the thickness is about 10 μm or less, the strength against shear stress parallel to the joint surface can be effectively improved. From this viewpoint, the range of the surface roughness Ra is preferably about 1 to 70 μm, about 1 to 30 μm, about 1 to 10 μm, about 3 to 70 μm, about 3 to 30 μm, about 3 to 10 μm, and about 8 to about 10 μm. About 70 μm, about 8 to 30 μm, about 8 to 10 μm. The surface roughness Ra is an arithmetic average roughness measured using a contact roughness meter in accordance with JIS B0601: 2013. Surfcom NEX manufactured by Tokyo Seimitsu Co., Ltd. can be used as the contact type roughness meter.

  The fiber may not be exposed on the surface of the fiber-reinforced plastic, or the fiber may be exposed. At the same surface roughness Ra, it is preferable that the fibers are exposed, which is more preferable in terms of bonding. However, the laminated film of the present invention improves the strength against shear stress parallel to the bonding surface in the formed body after bonding. Therefore, even if the fibers are not exposed on the surface of the fiber-reinforced plastic, the strength against shear stress parallel to the joint surface can be effectively improved. The surface of the fiber reinforced plastic can be exposed for the purpose of adjusting the surface roughness Ra of the fiber reinforced plastic. In order to expose the fibers of the fiber reinforced plastic, a process of removing the matrix resin on the surface of the fiber reinforced plastic where the fibers are not exposed can be performed. The degree of exposure of the fiber on the surface of the fiber-reinforced plastic, that is, the ratio of the area occupied by the exposed fiber to the surface of the fiber-reinforced plastic is, for example, 0% or more, preferably about 5% or more, and more preferably about 10% or more. Can be Although there is no particular upper limit of the degree of exposure, since the laminated film of the present invention can improve the strength against shear stress parallel to the bonding surface in the molded article after bonding, the degree of exposure of the fiber on the surface of the fiber-reinforced plastic is reduced. Even with about 30% or less, the strength against shear stress parallel to the joint surface can be effectively improved. That is, the range of the degree of exposure of the fiber on the surface of the fiber-reinforced plastic is, for example, about 0 to 30%, preferably about 5 to 30%, and more preferably about 10 to 30%.

  When the material constituting the member is a metal, specific examples include aluminum, iron, stainless steel, copper, zinc, silver, gold, magnesium, titanium, brass, nickel, and an alloy containing at least one of these. Among these, aluminum, iron, stainless steel, titanium, brass, nickel and the like are preferable, and aluminum is more preferable. When the material constituting the member is ceramics, specific examples include glass, alumina, and zirconia. Of these, glass is more preferable.

  The surface roughness Ra of the resin and the inorganic substance is, for example, preferably about 10 nm or more, preferably about 0.5 μm or more, and more preferably about 1 μm or more. The upper limit of the surface roughness Ra is not particularly limited, but may be, for example, about 20 μm or less. Since the laminated film of the present invention can improve the strength against shear stress parallel to the joining surface in the molded article after joining, the upper limit of the surface roughness Ra is about 10 μm or less, preferably about 5 μm or less, more preferably Even when the thickness is about 3 μm or less, the strength against shear stress parallel to the joining surface can be effectively improved. That is, the range of the surface roughness Ra is about 10 nm to 20 μm, about 10 nm to 10 μm, about 10 nm to 5 μm, about 10 nm to 3 μm, about 0.5 to 20 μm, about 0.5 to 10 μm, and about 0.5 to 10 μm. About 5 μm, about 0.5 to 3 μm, about 1 to 20 μm, about 1 to 10 μm, about 1 to 5 μm, about 1 to 3 μm. The surface roughness Ra is an arithmetic average roughness measured using a contact roughness meter in accordance with JIS B0601: 2013. Surfcom NEX manufactured by Tokyo Seimitsu Co., Ltd. can be used as the contact type roughness meter.

  The materials constituting the first member and the second member may be the same or different. Further, the form of the first member and the second member when they are joined by heat welding may be in a molten state or a solid state. A specific example of the member in the molten state is a molten resin. The molten resin is cooled and solidified to form a resin member. Examples of the solid member include a resin member, a fiber-reinforced plastic member, a fiber and an uncured resin impregnated therein, and an inorganic member (for example, a metal member or a ceramic member). When the solid member is a fiber and an uncured resin impregnated in the fiber, the uncured resin is thermally cured by heat at the time of heat welding, thereby forming a fiber-reinforced plastic member. In addition to the first member and the second member, another member may be joined using the laminated film of the present invention. That is, at least two members are joined by the laminated film of the present invention. The materials constituting the other members may be the same or different from the first member and the second member, and may be in a molten state when joined by heat welding. Or a solid, and when solid, may contain an uncured resin.

  The mode of joining two or more members using the laminated film of the present invention is not particularly limited as long as two or more members are joined via the laminated film. In this case, the first member / laminated film / second member / laminated film / other members may be sequentially laminated, or the first member and other members may be arranged and arranged on one surface of the laminated film, and A mode in which the second member is arranged on the other surface of the film, and the three members are joined via one laminated film is exemplified. Further, the laminated film may be present on the entire surface between the first member and the second member to join these members, or may be present on a part between the first member and the second member and be a part of these members. The members may be joined.

  These members may contain various additives such as a lubricant, an antioxidant, an ultraviolet absorber, a light stabilizer, and a colorant (eg, a pigment or a dye) as necessary.

  Preferred combinations of the first member and the second member thermally welded by the laminated film 10 of the present invention include, for example, a combination of a resin member and a metal member, a combination of a resin member and a resin member, and a combination of a resin member and a ceramic member. Combination, metal member and ceramic member, metal member and metal member combination, ceramic member and ceramic member combination, fiber reinforced plastic member and metal member combination, fiber reinforced plastic member and resin member Combinations, combinations of a fiber reinforced plastic member and a ceramic member, and the like. As will be described later, when the resin member is obtained by cooling and solidifying the molten resin, and when the fiber reinforced plastic member is obtained by thermosetting the fiber and the impregnated uncured resin, molding and heat treatment are performed. Welding can be performed in one step.

  The thickness of at least one of the first member and the second member is about 1 mm or more as a lower limit. The thickness of the member refers to the maximum thickness of the member. Since a member having such a thickness constitutes a molded body having a considerable thickness after joining, the molded body easily receives shear stress parallel to the joining surface. By joining members having such a thickness using the laminated film 10 of the present invention, a laminated body having excellent strength against the shear stress can be obtained. The present invention is particularly useful when the thickness of both the first member and the second member where the molded body is more easily subjected to shear stress parallel to the joint surface is about 1 mm or more. The thickness of at least one, preferably both members, is preferably 1.3 mm or more, more preferably 1.5 mm or more. The upper limit of the member is not particularly limited, but is, for example, about 20 mm or less. That is, the thickness range is, for example, about 1 to 20 mm, preferably about 1.3 to 20 mm, and more preferably about 1.5 to 20 mm.

  The shape and size of the member are not particularly limited, and may be a shape and size corresponding to a molded body manufactured by joining the members. Examples of the shape of the solid member include members having various shapes such as a plate shape, a pin shape such as a thumbtack, a concave shape, a convex shape, and an uneven shape. The members of various shapes include, for example, molded members. In the present invention, the molded article manufactured by joining the members can be suitably used for applications such as interior and exterior members of automobiles. Therefore, the material, shape, size, and the like of the member can be selected from those suitable for these uses.

2. Laminated body and molded body The laminated body of the present invention is characterized in that the first member 30 and the second member 40 or the precursor of the second member 40 are laminated via the laminated film 10 of the present invention. The details of the laminated film 10, the first member 30, and the second member 40 of the present invention are as described above. The precursor of the second member 40 is formed of a fiber-reinforced plastic and the matrix resin of the fiber-reinforced plastic is a thermosetting resin, as described below as a second member precursor 40a in FIG. Is a prepreg of a fiber-reinforced plastic in a state before the thermosetting resin is cured.

  The laminate of the present invention only needs to have a shape in which the first member 30 and the second member 40 or the precursor of the second member 40 are laminated with the laminated film 10 interposed therebetween. If there are three members, the first member / laminated film / second member or the precursor of the second member is sequentially laminated. If there are three members to be laminated, the first member / laminated film is used. / The second member or the precursor of the second member / the laminated film / the other member is laminated in order, or the first member and the other member are arranged side by side on one surface of the laminated film, and the other of the laminated film , The second member or a precursor of the second member is disposed on the surface of the first member, and three members are laminated via one laminated film. Further, the laminated film may exist on the entire surface between the first member and the second member or the precursor of the second member, and these members may be laminated, or the first member and the second member or the second member may be laminated. These members may be present in a part between the precursors of the members and stacked.

  The laminate of the present invention only needs to laminate the first member 30 and the second member 40 or the precursor of the second member 40 via the laminated film 10, and the first member 30 and the second member 40 or the second member 40 may be laminated. The precursor of the member 40 may or may not be joined by heat welding via the laminated laminated film 10 of the present invention.

  The molded body 20 of the present invention is characterized in that a first member 30 and a second member 40 are heat-welded with the laminated film 10 of the present invention, for example, as shown in the schematic diagram of FIG. That is, the molded body 20 of the present invention is in a joined state and a molded state via the laminated film 10 of the present invention. The details of the laminated film 10, the first member 30, and the second member 40 of the present invention are as described above.

  The molded body 20 of the present invention is formed into an arbitrary shape. For example, FIG. 5 shows an embodiment in which the molded body 20 of the present invention has a plate shape. FIG. 10 shows an embodiment in which the molded body 20 of the present invention is molded by a mold.

  The molded body 20 of the present invention can be manufactured by heat-welding the first member 30 and the second member 40 or the precursor of the second member 40 via the laminated film 10 in the above-described laminated body. In this case, specifically, in a state where the laminated film 10 is arranged between the first member 30 and the second member 40 or the precursor of the second member 40, the surface of the laminated film 10 is heated and pressed. The precursor of the second member 40 is thermally cured by melting. Thereafter, by cooling the laminated film 10, the heat-melted surface is solidified, whereby a molded body 20 in which the first member 30 and the second member 40 are thermally welded (joined) via the laminated film 10 is obtained. .

  For example, when the first member 30 is made of metal and the second member 40 is made of fiber reinforced plastic, when the matrix resin of the fiber reinforced plastic is a thermosetting resin, when the matrix resin of the fiber reinforced plastic is a thermosetting resin, The state of the member is preferably a state after the thermosetting resin is cured. In this case, the laminated film 10 is sandwiched between a first metal member formed into a predetermined shape and a fiber-reinforced plastic (after curing) formed into a predetermined shape, and heat welding is performed by pressing and heating. Thus, a dissimilar material joined body in which the first member and the second member are joined can be obtained.

  In the above aspect, when the matrix resin of the fiber-reinforced plastic constituting the second member 40 is a thermosetting resin, the state of the member at the time of heat welding includes a state before the thermosetting resin is cured, That is, it may be a precursor of the second member 40. In this case, a laminate in which a first member made of metal and a prepreg made of a fiber-reinforced plastic, which is a precursor of the second member 40, are laminated via the laminated film 10 is heated to perform heat welding and heat of the prepreg. Curing and molding can be performed simultaneously, that is, in one step, whereby a joined body of different materials in which the first member and the second member are joined can be obtained. More specifically, as shown in a series of schematic diagrams of FIGS. 7 to 9, for example, a laminated film 10 is attached to a metal member (first member 30) and a prepreg (second member precursor 40 a) of fiber-reinforced plastic. (FIG. 7), and the laminate is deformed by pressing or hot pressing with a mold 60 or the like, and the prepreg (second member precursor) of the fiber-reinforced plastic is heated by heating the laminate. The thermosetting of 40a) and the heat welding by melting the laminated film 10 are performed (FIG. 8). After the mold 60 is cooled, as shown in FIG. 9, a molded body 20 in which the first member 30 and the second member 40 (after curing) are joined by the laminated film 10 is obtained.

  Further, in the above embodiment, when the matrix resin of the fiber reinforced plastic constituting the second member 40 is a thermoplastic resin, the first member made of metal and the second member made of fiber reinforced plastic are laminated. By heating the laminated body laminated via the film 10 and performing the heat welding and the thermoforming simultaneously, that is, in one step, it is possible to obtain a dissimilar material joined body in which the first member and the second member are joined. it can. More specifically, steps similar to the steps shown in the series of schematic diagrams of FIGS. 7 to 9 are performed except that the prepreg (second member precursor 40 a) of fiber reinforced plastic is changed to fiber reinforced plastic 40. It can be carried out. That is, a laminate is formed by laminating a metal member (first member 30) and a fiber-reinforced plastic (second member 40) via the laminated film 10, and the laminate is plastically deformed by hot pressing with a mold or the like. Then, heat welding by melting the laminated film 10 is performed by heating the laminated body. After cooling the mold, the molded body 20 in which the first member 30 and the second member 40 are joined by the laminated film 10 is obtained.

  The temperature at which the first member 30 and the second member 40 (or the second member precursor 40a) are thermally welded through the laminated film 10 is not particularly limited as long as the surface of the laminated film 10 is thermally melted. However, the temperature is preferably about 140 to 280 ° C, more preferably about 160 to 250 ° C. When joining the fiber reinforced plastics, the curing temperature (in the case of a thermosetting resin) or the softening point (in the case of a thermoplastic resin) of the matrix resin in the fiber reinforced plastic is further considered as appropriate. The pressure (surface pressure) at the time of heat welding is not particularly limited, but is preferably about 0.1 to 5 MPa, more preferably about 0.2 to 3 MPa. The heating and pressurizing time for heat welding is usually about 1 to 30 seconds.

  In the present invention, in addition to the method illustrated in FIGS. 7 to 9, at least one of the first member 30 and the second member 40 to be joined is formed by cooling and solidifying a molten resin. You may get a body. In this case, molding and joining can be performed in one step. Specifically, while one side of the laminated film 10 is in contact with one solid member, the molten resin is supplied to the other side, and cooled while molding the molten resin with a mold or the like. And joining of the solid member can be performed in one step.

  The temperature of the molten resin when supplying the molten resin to the surface of the laminated film 10 is not particularly limited as long as the molten resin 40b can maintain the molten state, and varies depending on the type of the molten resin. From the viewpoint of suitably joining the molten resin 40b and the solid member (the first member 30) via the film 10, the temperature is preferably about 150 to 300 ° C, more preferably about 190 to 250 ° C.

  The resin constituting the molten resin is not particularly limited as long as it is a resin that is thermally melted. However, from the viewpoint of suitably joining the molten resin 40b and the solid member (the first member 30) via the laminated film 10, it is preferable. , Polyolefin, polyester, polyamide, epoxy resin, acrylic resin, fluororesin, silicone resin, ABS resin and the like. Among resins, polyolefins such as polyethylene and polypropylene, epoxy resins, ABS resins, and the like are particularly preferable.

  When one of the first member 30 and the second member 40 to be joined is a solid member, for example, as shown in a series of schematic diagrams of FIGS. 10 to 12, the solid member (first member 30) Then, in a state where the first heat-welding resin layer 1 of the laminated film 10 is temporarily attached (FIG. 10), the molten resin 40b is supplied to the surface of the laminated film 10 on the second heat-welding resin layer 2 side ( 11), the molten resin 40b and the solid member (first member 30) can be joined via the laminated film 10 (FIG. 12). Also at this time, as shown in FIG. 12, the supplied molten resin is cooled while being molded by the mold 60 or the like, so that the molding and the joining can be performed in one step. In addition, as shown in FIG. 12, when the solid member (first member 30) has flexibility that can be formed by a mold 60 or the like, the solid member (first member 30) is simultaneously formed. It can be carried out. After cooling the molten resin 40b, a molded body 20 (see FIG. 9) in which the first member 30 and the second member 40 are joined by the laminated film 10 is obtained.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the embodiments.

<Material of laminated film (heat-welding film), member to be joined, and measurement of physical properties thereof>
In Examples and Comparative Examples, the degree of acid modification of the material, the melt mass flow rate (MFR), the melting peak temperature, the softening point, the tensile modulus and the heat shrinkage, and the surface roughness of the member to be joined and the fiber reinforced plastic The fiber exposure is a value measured by the following method.

(Measurement of acid modification degree)
First, in _{ODCB-d4 / C 6 D 6} ( volume ratio 4/1) solvent, was measured and ¹ H-NMR of ¹ H-NMR and methyl esters of the acid-modified polyolefin to be measured (acid-modified polyolefin) . By comparing the obtained ¹ H-NMR, the peak of the methyl esterified product in which the acid was derivatized was identified. Furthermore, from the ¹ H-NMR of the acid-modified polyolefin (before methyl esterification), the area of the impurity-derived peak overlapping at the peak position of the methyl ester in the ¹ H-NMR of the methyl ester was identified. By subtracting the peak area derived from impurities from the peak area at the peak position of the methyl esterified product, the peak area of the methyl esterified product was obtained, and the degree of acid modification was calculated from the acid-derived peak area derived based on this. In addition, about the polyolefin which is not acid-modified, the acid modification degree was 0 weight%.

(Measurement of melt mass flow rate (MFR))
According to a method based on JIS K7210: 2014, the melt mass flow rate of the heat-fusible resin layer was measured using a melt indexer. "MiniLab" manufactured by HAAKE was used as a melt indexer. The measurement conditions were a measurement temperature of 230 ° C. and a load of 2.16 kg.

(Measurement of melting peak temperature)
The melting peak temperature of the intermediate layer was measured using a differential scanning calorimeter (DSC). As a device, "DSC-60 Plus" manufactured by Shimadzu Corporation was used. As measurement conditions, a temperature rising rate was 10 ° C./min, a temperature measurement range was 100 to 350 ° C., and an aluminum pan was used as a sample pan. The peak having the largest peak was defined as a melting peak.

(Measurement of softening point)
The softening point was measured using the probe displacement measurement. First, as shown in the conceptual diagram of FIG. 14, a position on the surface of the heat-welding resin layers 1 and 2 at the end of the laminated film (for example, if the heat-welding resin layer 1 in the laminated film 10 of FIG. , P. The following description will be made with the heat-welding resin layer 1 as a representative example.) The probe 90 is installed (measurement start A in FIG. 14). The end portion at this time is a portion where the cross section of the heat-welding resin layer 1 is obtained by cutting in the thickness direction so as to pass through the center portion of the laminated film. Cutting was performed using a commercially available rotary microtome or the like. An atomic force microscope equipped with a nanothermal microscope composed of a cantilever with a heating mechanism, for example, an afm plus system manufactured by ANASIS INSTRUMENTS was used, and a probe manufactured by ANASYS INSTRUMENTS was used. The tip radius of the probe was 30 nm or less, the set value of the deflection of the probe was -4 V, and the heating rate was 5 ° C./min. Next, when the probe is heated in this state, the heat from the probe 90 causes the surface of the heat-welding resin layer 1 to expand as shown in FIG. Value (the position when the temperature of the probe 90 is 40 ° C.). When the heating temperature further increased, the heat-welding resin layer 1 softened, and the probe 90 pierced the heat-welding resin layer 1 as shown in FIG. 14C, and the position of the probe 90 lowered. In measuring the displacement of the probe 90, the laminated film to be measured is in an environment of room temperature (25 ° C.), and the probe 90 heated to 40 ° C. is placed on the surface of the heat-welding resin layer 1 and measured. Started. The softening point of the heat-welding resin layer 1 is a temperature at which the deflection of the probe 90 becomes maximum in the measurement of the displacement of the probe. In the measurement of the softening point of the heat-welding resin layer 1, the temperature at which the deflection of the probe 90 becomes maximum is read for five samples of the heat-welding resin layer 1 to be measured. The average value of the three temperatures excluding the maximum value and the minimum value was defined as the softening point.

(Measurement of tensile modulus)
The tensile modulus of the intermediate layer was measured in the same manner as the measurement of the tensile modulus of the laminated film (heat-welding film) described later.

(Measurement of heat shrinkage)
When the intermediate layer is a film, the heat shrinkage was measured in two directions of MD and TD in accordance with JIS K 7133: 1999 at a test temperature of 200 ° C. and a heating time of 10 minutes. When the intermediate layer is a fiber, the test temperature is 200 ° C. in two directions of MD (longitudinal direction of the nonwoven fabric roll) and TD (direction orthogonal to the longitudinal direction of the nonwoven fabric roll) in accordance with JIS K 7133: 1999. The heat shrinkage was measured under the conditions of a heating time of 10 minutes.

(Measurement of surface roughness)
The surface roughness Ra of each member was measured as an arithmetic average roughness in accordance with JIS B0601: 2013 using Surfcom NEX manufactured by Tokyo Seimitsu Co., Ltd., which is a contact-type roughness meter.

(Measurement of fiber exposure)
The degree of fiber exposure of the fiber reinforced plastic member was measured by observing the surface with a microscope and calculating the area ratio occupied by the exposed portions of the fibers.

<Production of laminated film (heat-welding film) and measurement of each physical property>
(Example 1)
One side of a polyethylene naphthalate (PEN) film (tensile elastic modulus 6000 MPa, melting peak temperature 262 ° C., heat shrinkage TD 1.3%, MD 1.1%, thickness 12 μm) as an intermediate layer is heat-weldable resin A maleic anhydride-modified polypropylene resin (acid modification degree: 0.09% by weight, MFR: 8 g / 10 min, softening point: 140 ° C.) was extruded with a T-die extruder to a thickness of 44 μm, and the first heat-welding resin layer ( PPa) was formed. Next, on the other surface of the intermediate layer, the same maleic anhydride-modified polypropylene resin was extruded and applied to a thickness of 44 μm using a T-die extruder to form a second heat-welding resin layer (PPa). A laminated film in which a welding resin layer (PPa, thickness of 44 μm) / intermediate layer (PEN, thickness of 12 μm) / second heat-welding resin layer (PPa, thickness of 44 μm) is laminated in this order as a heat-welding film. Obtained.

(Example 2)
As an intermediate layer, a melt anisotropic wholly aromatic polyester (polyarylate (PAR)) nonwoven fabric (tensile elasticity 3000 MPa, melting peak temperature 250 ° C., heat shrinkage TD 0.0%, MD 0.0%, basis weight 9 g / m ² , thickness) 40 μm), and a maleic anhydride-modified polypropylene resin (acid modification degree: 0.09% by weight, MFR: 9 g / 10 min, softening point: 140 ° C.) was used as the heat-sealable resin in the same manner as in Example 1. Then, a laminated film in which a first heat-welding resin layer (PPa, thickness 20 μm) / intermediate layer (PAR, thickness 40 μm) / second heat-welding resin layer (PPa, thickness 20 μm) is stacked in this order. Obtained as a heat weldable film.

(Comparative Example 1)
Maleic anhydride-modified polypropylene resin film (PPa, acid modification degree 0.09 wt%, MFR 8 g / 10 min, softening point 140 ° C, tensile modulus 1000 MPa, heat shrinkage TD 3.6%, MD79.1%, thickness 100 μm ) Was used as a heat-welding film.

(Comparative Example 2)
Except for using an unstretched polypropylene film (CPP, tensile modulus 1400 MPa, melting peak temperature 290 ° C., heat shrinkage TD 3.0%, MD 81.0%) as the intermediate layer, A laminated film in which a first heat-welding resin layer (PPa, thickness 30 μm) / intermediate layer (CPP, thickness 40 μm) / second heat-welding resin layer (PPa, thickness 30 μm) is laminated in this order is heat-sealed. Obtained as a functional film.

(Measurement of tensile modulus)
In a method according to JIS K7161: 2014, a test piece (rectangular) cut out of a film into a 25 mm width and a 120 mm length so that MD is a long side is subjected to a tensile compression tester (25 ° C.). Calculated according to the following equation from the first straight line portion of the tensile stress-strain curve obtained by measuring with a tensile speed of 200 mm / min and a distance between chucks of 100 mm using Orientec Co., Ltd. Tensilon RTC-1250A). did.
E = Δρ / Δε
E: Tensile modulus Δρ: Stress difference due to original mean cross-sectional area between two points on a straight line Δε: Strain difference between the same two points

(Measurement of heat shrinkage)
According to a method based on JIS K 7133: 1999, the heat shrinkage rate of each heat-welding film obtained above was measured at a test temperature of 200 ° C. and a heating time of 10 seconds. Table 1 shows the results.

<Measurement of each physical property of molded article>
Test samples and molded articles using the first member and the second member shown in Table 1 were prepared under the conditions described below, and the seal strength, the shear strength, and the peel strength were measured. In Table 1, AL of the first member indicates aluminum (A1100 of JIS H 4000: 2014), and fiber-reinforced plastic of the second member is a fiber-reinforced plastic obtained by impregnating carbon fibers with epoxy resin after curing. Show things.

(Measurement of seal strength)
The seal strength (N / 15 mm) between each surface of each heat-welding film obtained above and the first member and the second member shown in Table 1 was measured. More specifically, first, each heat-weldable film was cut into a size of 50 mm in the length direction (y direction) × 25 mm in the width direction (x direction). Next, for example, when measuring the sealing strength of the heat-weldable film of the example as a heat-weldable film, as shown in FIG. 6, the first heat-welding of each laminated film 10 (heat-weldable film) of the example The conductive resin layer or the second heat-welding resin layer and each member 50 at a depth (y direction) of 7 mm (heat sealing conditions: temperature 190 ° C., surface pressure 1 MPa, pressing time 5 seconds). A test sample was obtained. In the schematic diagram of FIG. 6, a region S surrounded by a broken line indicates a heat-sealed region. Note that a release sheet was sandwiched between portions other than the region to be heat-sealed, and heat-sealed at a depth of 7 mm. Next, the test sample was cut to a width of 15 mm as shown in FIG. 6A so that the seal strength (N / 15 mm) in the width direction (x direction) of 15 mm could be measured. Next, as shown in FIG. 6B, the laminated film 10 was peeled from the fixed member 50 in the length direction (y direction) using a tensile tester. At this time, the peeling speed was 300 mm / min, and the maximum load until peeling was defined as the seal strength (N / 15 mm). In addition, as a member in the preparation of the test sample, a resin member having a thickness of 4 mm, a fiber reinforced plastic member having a thickness of 4 mm, and a metal member having a thickness of 0.5 mm was used. Each seal strength is an average value (n = 3) measured by preparing three test samples in the same manner. Table 1 shows the results.

(Measurement of peel strength)
The peel strength (N / 25 mm) between the first member and the second member in the laminate composed of the first member, the heat-weldable film, and the second member described in Table 1 was measured. More specifically, first, each heat-weldable film was cut into a size of 160 mm in the length direction × 25 mm in the width direction. The first member 70 was cut into a size of 250 mm in the length direction × 25 mm in the width direction, and the second member 80 was cut into a size of 200 mm in the length direction × 25 mm in the width direction. Next, as shown in FIG. 16 (i), each laminated film 10 (heat-welding film), the first member 70 and the second member 80 are overlapped in the longitudinal direction, and the longitudinal direction is 160 mm × A test sample was obtained by heat sealing a region of 25 mm in the width direction (heat sealing conditions: temperature 190 ° C., surface pressure 1 MPa, pressurizing time 30 seconds). Next, the test sample was fixed to a peeling test jig on the second member 80 side, and the first member 70 was peeled off using a tensile tester as shown in FIG. 16 (ii). At this time, the peeling speed was set to 100 mm / min, and the average load at the portion excluding the portion from the peeling start position to the peeling length of 25 mm was taken as the peel strength (N / 25 mm). In addition, as a member in the preparation of the test sample, a resin member having a thickness of 4 mm, a fiber reinforced plastic member having a thickness of 4 mm, and a metal member having a thickness of 0.5 mm was used. Each peel strength is an average value (n = 3) measured by preparing three test samples in the same manner. Table 1 shows the results.

(Measurement of shear strength)
Using the heat-welding films of the examples and the comparative examples, the shear strength (MPa) of the molded body obtained by heat-welding the first member and the second member under the following conditions was measured. The measurement of the shear strength was performed by a method based on the provisions of ISO19095-2 and ISO19095-3. The sizes of the first member and the second member in the preparation of the test sample were 45 mm in length × 10 mm in width, and the thickness was 3 mm for the resin member, 3 mm for the fiber reinforced plastic member, and 3 mm for the metal member. 1.5 mm. Each heat-welding film had a length of 5 mm and a width of 10 mm. For example, when measuring the shear strength of the laminated film (heat-welding film) of the example, as shown in FIG. The laminated film 10 is disposed between the first member 70 and the second member 80 via the laminated film 10 under the conditions of a temperature of 190 ° C., a surface pressure of 1.5 MPa, and 20 seconds. A molded article was obtained by heat welding. Further, the laminated film 10 was arranged such that the whole of both surfaces was heat-sealed (that is, the heat-sealing area was 5 mm long × 10 mm wide on one side). Although not shown in FIG. 13, the first member 70 and the second member 80 are provided in order to perform measurement on the first member 70 and the second member 80 joined in a state parallel to each other. Each was joined by adjusting the height using a compensation member. The compensating member for adjusting the height of the first member 70 uses a member having the same material and shape as the first member 70, and the compensating member for adjusting the height of the second member 80 is the same material as the second member 80. Shaped members were used. Next, using a tensile tester, the molded body was pulled in the length direction (tensile speed: 10 mm / min), and the maximum load (N) required for delamination or breakage of the molded body was measured. The shear strength (MPa) was calculated by dividing by the heat sealing area (length 5 mm × width 10 mm). Table 1 shows the results.

(Result 1)
As the results in Table 1 show, the heat-welding films having a tensile modulus of less than 1500 MPa (Comparative Examples 1 and 2) have a shear strength after joining of the members of less than 10 MPa, so that the shearing force is parallel to the joining surface. It was not suitable for use in obtaining a molded article by joining members of 1 mm or more that are susceptible to stress. On the other hand, the laminated films for thermal welding having a tensile modulus of 1500 MPa or more (Examples 1 and 2) achieved extremely excellent shear strength of 10 MPa or more after joining the members. Therefore, it was shown that the laminated films of Examples 1 and 2 were useful for the purpose of joining a member of 1 mm or more, which is likely to receive shear stress parallel to the joining surface, to obtain a molded body.

(Example 3)
Except that an unstretched polypropylene (CPP) film (degree of acid modification: 0% by weight, MFR: 3.6 g / 10 min, softening point: 155 ° C.) was used as the heat welding resin, the first heat was applied in the same manner as in Example 1. A laminated film in which a weldable resin layer (CPP, thickness 44 μm) / intermediate layer (PEN, thickness 12 μm) / second heat-weldable resin layer (CPP, thickness 44 μm) is laminated in this order as a heat-adhesive film. Obtained. As a result of measuring the tensile elastic modulus and the thermal shrinkage of this laminated film in the same manner as described above, the tensile elastic modulus was 6300 MPa, and the thermal shrinkage was TD: 2.1% and MD: 2.6%. The sealing strength between this laminated film and polyethylene terephthalate (PET) was measured in the same manner as described above. As a result, the sealing strength was 20 N / 15 mm. Using this laminated film, two polyethylene terephthalate (PET) plates having a thickness of 1.5 mm were joined by heat welding.

(Comparative Example 3)
A 100 μm unstretched polypropylene (CPP) film (acid modification degree: 0% by weight, MFR: 3.6 g / 10 min, softening point: 155 ° C.) was prepared as a heat-weldable film. As a result of measuring the tensile elastic modulus and the thermal shrinkage of this heat-welding film in the same manner as described above, the tensile elastic modulus was 1400 MPa, and the thermal shrinkage was TD: 3.0% and MD: 81.0%. The seal strength between this heat-welding film and polyethylene terephthalate (PET) was measured in the same manner as described above. As a result, the seal strength was 20 N / 15 mm. Using this heat-welding film, two polyethylene terephthalate (PET) plates having a thickness of 1.5 mm were joined by heat welding.

(Result 2)
Also in Example 3 and Comparative Example 3, similarly to the relationship between Example 1 and Comparative Example 1, the tensile elastic modulus was 1500 MPa or more for a heat-welding film (Comparative Example 3) having a tensile elastic modulus of less than 1500 MPa. The heat-sealed laminated film (Example 3) was extremely excellent in shear strength after joining the members.

REFERENCE SIGNS LIST 1 first heat-welding resin layer 2 second heat-welding resin layer 3 intermediate layer 4 thermoplastic resin layer 10 laminated film 20 molded body 30 first member 40 second member 40 a second member precursor 50 member 60 mold 70 First member 80 Second member 90 Probe S Heat-sealed region P Position of surface of intermediate layer at end of laminated film

Claims (11)

A laminated film for joining the first member and the second member,
The laminated film includes at least a first heat-welding resin layer, an intermediate layer, and a second heat-welding resin layer in this order,
A tensile modulus of 1500 MPa or more;
A laminated film, wherein at least one of the first member and the second member has a thickness of 1 mm or more.   The laminated film according to claim 1, wherein the thickness of both the first member and the second member is 1 mm or more.   The laminated film according to claim 1, wherein the intermediate layer is a film.   The laminated film according to any one of claims 1 to 3, wherein at least one of the first heat-welding resin layer and the second heat-welding resin layer contains a modified polyolefin.   The laminated film according to any one of claims 1 to 4, wherein the intermediate layer has a tensile modulus of 1500 MPa or more.   The laminated film according to any one of claims 1 to 5, wherein one of the first member and the second member is made of metal.   The laminated film according to any one of claims 1 to 6, wherein one of the first member and the second member is made of a fiber-reinforced plastic.   The laminated film according to claim 7, wherein the fibers in the fiber reinforced plastic are glass fibers or carbon fibers.   The peak derived from maleic anhydride is detected when at least one of the first heat-welding resin layer and the second heat-welding resin layer is analyzed by infrared spectroscopy. 3. The laminated film according to item 1.   A laminate, wherein the first member and the second member or the second member precursor are laminated via the laminated film according to any one of claims 1 to 9.   A molded article in which the first member and the second member are joined and molded via the laminated film according to any one of claims 1 to 9.

Images