JP2017100324A - Laminated structure and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated structure in which a resin layer is laminated on an aluminum-based base material, which is excellent in flexibility and adhesive strength between layers. SOLUTION: It is characterized by having an aluminum-based base material, aluminum-based particles welded to at least a part of the surface of the aluminum-based base material, and a resin layer fixed in a state of covering the aluminum-based particles. Laminated structure. [Selection diagram] None

Description

  The present invention relates to a laminated structure and a manufacturing method thereof. The laminated structure of the present invention is useful as a constituent material for packaging materials, solar cell backsheets, wallpaper, heat shield sheets, light shield sheets, heat insulating sheets, housings, and circuit boards.

  Conventionally, when bonding an aluminum foil and another material, it is known to provide an uneven portion by anodizing the surface of the aluminum foil in order to increase the adhesion strength between the layers.

For example, Patent Document 1 relates to a housing, an electronic device, and a composite molding method. Claim 1 includes a “method of composite molding of a metal plate and a resin,
An oxide film layer forming step of forming an oxide film layer on at least a part of the metal plate;
After the oxide film layer forming step, an adhesive layer forming step of forming an adhesive layer on the oxide film layer,
And a resin injection step of injecting a resin into the oxide film layer through an adhesive layer and performing composite molding. Is disclosed. Further, claim 4 discloses an embodiment in which the metal plate is aluminum or an aluminum alloy, and the oxide film layer is an anodized film layer that has been anodized.

  However, alumite-treated aluminum foil is poor in flexibility, and winding and plastic working are difficult. In addition, if the anodized aluminum foil is forcibly bent, the anodized surface is cracked, so that the design property may be lowered, and the strength of the cracked portion is lowered.

JP 2005-271477 A

  An object of the present invention is to provide a laminated structure in which a resin layer is laminated on an aluminum-based substrate, and which is excellent in flexibility and interlayer adhesive strength. It is another object of the present invention to provide a manufacturing method suitable for manufacturing the laminated structure of the present invention.

  As a result of intensive studies to achieve the above object, the present inventor has found that the above object can be achieved by a laminated structure having a specific laminated structure, and has completed the present invention.

That is, this invention relates to the following laminated structure and its manufacturing method.
1. A laminated structure comprising: an aluminum-based substrate; aluminum-based particles welded to at least a part of the surface of the aluminum-based substrate; and a resin layer fixed in a state of covering the aluminum-based particles.
2. A first structure comprising a first aluminum-based substrate and first aluminum-based particles welded to at least part of the surface of the first aluminum-based substrate;
A second aluminum substrate and a second structure composed of second aluminum particles welded to at least part of the surface of the second aluminum substrate;
The first structure and the second structure are laminated via a resin layer,
The resin layer is a laminated structure that is fixed in a state of covering both the first aluminum-based particles and the second aluminum-based particles.
3. The average particle diameter _{D 50} is 1.5μm or more 15μm or less, the laminated structure according to Item 1 or 2 of the aluminum-based particles.
4). A method of manufacturing a laminated structure,
(1) a first step of forming a film of a composition containing aluminum-based particles on at least a part of the surface of an aluminum-based substrate;
(2) a second step of welding the aluminum-based particles by heat-treating the film;
(3) a third step of forming a resin layer fixed in a state of covering the aluminum-based particles;
In order.

  In the laminated structure of the present invention, the aluminum-based particles are welded to at least a part of the surface of the aluminum-based substrate, and the resin layer is fixed in a state of covering the aluminum-based particles. Excellent adhesion strength between the substrate and the resin layer. In addition, unlike the prior art, it does not use an anodic oxide coating that is inferior in plastic deformability, and is composed mainly of an aluminum metal component and a resin component, so that it has excellent flexibility. Such a laminated structure of the present invention is useful as a constituent material for packaging materials, solar cell backsheets, wallpaper, heat-shielding sheets, light-shielding sheets, heat-insulating sheets, housings, and circuit boards.

2 is a view showing a cross-sectional photograph of a laminated structure produced in Example 1. FIG. It is a figure which shows the photograph of the peeling interface after peeling the laminated structure produced in Example 1. FIG. 6 is a view showing a cross-sectional photograph of a bent portion of a laminated structure produced in Comparative Example 2. FIG. 6 is a view showing a cross-sectional photograph of a bent portion of a laminated structure produced in Example 3. FIG. 6 is a view showing a cross-sectional photograph of a bent portion of a laminated structure produced in Comparative Example 2. FIG. In detail, the cross-sectional photograph of FIG. 3 is enlarged and cracks in the alumite layer are shown.

1. Laminated structure The laminated structure of the present invention includes an aluminum-based substrate, aluminum-based particles welded to at least a part of the surface of the aluminum-based substrate, and a resin layer fixed in a state of covering the aluminum-based particles. It is characterized by having.

  In the laminated structure of the present invention having the above features, the aluminum-based particles are welded to at least a part of the surface of the aluminum-based substrate, and the resin layer is fixed in a state of covering the aluminum-based particles. Excellent adhesion strength between the aluminum-based substrate and the resin layer.

  Hereinafter, main components of the laminated structure will be described.

  In the present invention, it is preferable to use an aluminum foil as the aluminum-based substrate.

  The aluminum foil is not particularly limited, and a pure aluminum foil or an aluminum alloy foil can be used. When an aluminum alloy foil is used, as components, silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn), titanium (Ti ), Aluminum alloy foil to which at least one alloy element of vanadium (V), gallium (Ga), nickel (Ni) and boron (B) is added within a necessary range, or aluminum with a limited content of the above alloy elements A foil can be used.

  The thickness of the aluminum-based substrate is not particularly limited. In view of productivity, in the case of an aluminum foil, the thickness is preferably 5 μm or more and 200 μm or less, and particularly preferably 15 μm or more and 150 μm or less. However, an aluminum plate material can also be applied to the aluminum-based substrate. In this case, the thickness of the aluminum plate can be about 200 μm or more and 2000 μm or less.

  The said aluminum foil can use what is manufactured by a well-known method. For example, a molten aluminum or aluminum alloy having the above predetermined composition is prepared, and an ingot obtained by casting the molten metal is appropriately homogenized. Thereafter, an aluminum foil can be obtained by subjecting the ingot to hot rolling and cold rolling.

  In addition, you may perform an intermediate annealing process within the range of 50-500 degreeC in the middle of said cold rolling process, especially 150-400 degreeC. Moreover, it is good also as a soft foil by giving an annealing process within the range of 150-650 degreeC after the said cold rolling process, especially 350-550 degreeC.

  In the present invention, the surface of the aluminum-based substrate may be roughened prior to welding the aluminum-based particles described later. The surface roughening method is not particularly limited, and known techniques such as cleaning, etching, blasting, and the like can be used.

  As the aluminum-based particles that are welded to at least a part of the surface of the aluminum-based substrate, for example, aluminum particles having an aluminum purity of 98.0% by mass or more are preferable. Examples of the aluminum-based particles include silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn), titanium (Ti), Aluminum alloy particles containing one or more of the elements such as vanadium (V), gallium (Ga), nickel (Ni), boron (B), and zirconium (Zr) as alloy elements may be employed. . The total content of these elements in the aluminum alloy is appropriately set according to the use, but is usually 2% by mass or less, and particularly preferably 1% by mass or less. In the examples of the present specification, the aluminum particles are also referred to as aluminum powder.

The average particle size of the aluminum-based particles may be determined as appropriate depending on the product application of the laminated structure, but preferably has an average particle diameter _{D 50} before welding is 1.5 [mu] m or more 15μm or less, 1.5 [mu] m or more 9.5μm The following is more preferable. As long as the average particle diameter D ₅₀ according a particular laminated structure having excellent adhesion to the resin layer to be described later. The average particle diameter D ₅₀ tends to interlaminar strength of the laminated structure is low at less than 1.5 [mu] m. On the other hand, if it exceeds 15 μm, the thickness of the laminated structure may increase, and the efficiency may be deteriorated in terms of cost and process.

The average particle size D ₅₀ in the present specification is a value obtained by measuring a particle size distribution by volume by laser diffraction method. The average particle diameter D ₅₀ of the particles after welding, a value measured by observing the cross-section after the welding with a scanning electron microscope. For example, the particles after welding are partially melted or in a state where the particles are connected to each other, but a portion having a substantially circular shape can be regarded as approximately granular. The average particle diameter D ₅₀ of the particles after welding can be obtained by converting the grain size distribution of number-based particle size distribution based on volume. The average particle diameter D ₅₀ after welding and the average particle diameter D ₅₀ before welding obtained in the above is substantially the same.

  The shape of the particle is not particularly limited, and any of a spherical shape, an indeterminate shape, a scale shape, a fibrous shape, and the like can be suitably used, but a spherical particle is particularly preferable.

  As the particles, those produced by a known method can be used. For example, an atomizing method, a melt spinning method, a rotating disk method, a rotating electrode method, a rapid solidification method, and the like can be mentioned. For industrial production, the atomizing method, particularly the gas atomizing method is preferable. That is, it is preferable to use particles obtained by atomizing the molten metal.

  The particles after welding may have a two-dimensional network structure. Moreover, it is preferable that the particles are welded (sintered) while maintaining voids. Specifically, it is preferable that each particle is connected by welding (sintering) while maintaining voids and has a three-dimensional network structure. That is, it is preferable that the sintered body has a three-dimensional network structure. Thus, when the particles after welding form a porous welded body (also referred to as a welded layer), the interlayer strength between the resin layer impregnated and fixed with the resin can be improved. The porosity of the weld layer is not limited, but is preferably 30% by volume to 70% by volume, and more preferably 40% by volume to 60% by volume. In addition, the porosity in this specification is a value calculated from thickness and mass.

  The welding layer is formed on one side or both sides of the aluminum-based substrate. When formed on one side, the thickness of the weld layer is preferably 1.5 μm or more and 150 μm or less, and more preferably 1.5 μm or more and 50 μm or less. When forming on both surfaces, it is preferable to arrange | position a welding layer symmetrically on both sides of an aluminum-type base material. The total thickness of the weld layers formed on both surfaces is preferably 3 μm or more and 300 μm or less, and more preferably 3 μm or more and 100 μm or less. The thickness of the welded layer is an average value of 5 points excluding the maximum value and the minimum value measured at 7 points with a micrometer.

  The interface strength (adhesive strength) between the aluminum-based substrate and the aluminum-based particle weld layer is preferably higher than the adhesive strength between the aluminum-based particle weld layer and the resin layer. In order to increase the interfacial strength (adhesion strength) between the aluminum-based substrate and the welded layer of aluminum-based particles, the second step described later includes aluminum-based particles formed on at least a part of the surface of the aluminum-based substrate. By heat-treating the coating film of the composition, the aluminum-based particles may be surely welded onto the aluminum-based substrate.

  The laminated structure of the present invention has a resin layer fixed in a state of covering aluminum particles deposited on at least a part of the surface of the aluminum substrate.

  A resin layer contains at least 1 sort (s), such as an adhesive agent, an adhesive, a hot melt, and an elastomer. Specific examples of the resin include polyolefin resins such as polyethylene, polypropylene, and polybutene, (meth) acrylic resins, polyvinyl chloride resins, polystyrene resins, polyvinylidene chloride resins, and ethylene-vinyl acetate copolymers. Saponified product, polyvinyl alcohol, polycarbonate resin, fluorine resin, polyvinyl acetate resin, acetal resin, polyester resin, polyamide resin, polyimide resin, epoxy resin, polyphenylene sulfide resin, polyacetal resin, liquid crystal Engineering plastics such as polymers, acrylic adhesives, rubber adhesives, urethane adhesives, polyester adhesives, silicone adhesives, ethylene-vinyl acetate resin adhesives, vinyl chloride adhesives, PVC-NBR blends Elast Chromatography, and urethane-based elastomer and the like. In addition to these resins, the resin layer may optionally contain, for example, a plasticizer, a stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, a filler, and other additives.

As a specific example of the laminated structure of the present invention, for example,
A first structure comprising a first aluminum-based substrate and first aluminum-based particles welded to at least part of the surface of the first aluminum-based substrate;
A second aluminum substrate and a second structure composed of second aluminum particles welded to at least part of the surface of the second aluminum substrate;
The first structure and the second structure are laminated via a resin layer,
Examples of the resin layer include a laminated structure that is fixed in a state of covering both the first aluminum-based particles and the second aluminum-based particles.

  The laminated structure of the present invention can be suitably used as a constituent material for packaging materials, solar cell backsheets, wallpaper, heat shield sheets, light shield sheets, heat insulating sheets, housings, and circuit boards.

  In the laminated structure of the present invention, a colored layer, an anticorrosive layer, an insulating layer, a heat insulating layer, and the like may be further laminated as long as the effects of the present invention are not hindered.

2. Manufacturing method of laminated structure The manufacturing method of the laminated structure of the present invention is not limited,
(1) a first step of forming a film of a composition containing aluminum-based particles on at least a part of the surface of an aluminum-based substrate;
(2) a second step of welding the aluminum-based particles by heat-treating the film;
(3) a third step of forming a resin layer fixed in a state of covering the aluminum-based particles;
Can be employed in this order (hereinafter referred to as “production method of the present invention”).

  Hereinafter, the manufacturing method of this invention is demonstrated for every process.

(First step)
In the first step, a film of the composition containing aluminum-based particles is formed on at least a part of the surface of the aluminum-based substrate.

  The description of the aluminum-based substrate is as described in the column of the laminated structure.

The description of the composition, average particle diameter D ₅₀ , shape, production method and the like of the aluminum-based particles (aluminum particles and / or aluminum alloy particles) is as described in the column of the laminated structure.

  The composition containing aluminum-based particles may contain at least one of a resin binder, a solvent, a sintering aid, a surfactant and the like in addition to the aluminum-based particles. Any of these may be known or commercially available. In the present invention, a paste composition containing at least one of a resin binder and a solvent is particularly preferable. A film can be efficiently formed by using this paste composition. Although content of the aluminum-type particle | grains in a paste composition is not limited, 30 to 90 mass% is preferable and 40 to 80 mass% is more preferable.

  The resin binder is not limited. For example, carboxy-modified polyolefin resin, vinyl acetate resin, vinyl chloride resin, vinyl chloride copolymer resin, vinyl alcohol resin, butyral resin, vinyl fluoride resin, acrylic resin, polyester resin, urethane resin Synthetic resins such as epoxy resin, urea resin, phenol resin, acrylonitrile resin, cellulose resin, paraffin wax, and polyethylene wax; natural resins such as wax, tar, glue, urushi, pine resin, beeswax, and wax can be suitably used. These binders may be volatilized by heat treatment described later depending on the molecular weight, the type of resin, and the like, and the residue remains together with the aluminum-based particles after the heat treatment, and can be properly used depending on the application.

  The solvent is not limited, and known solvents can be used. For example, in addition to water, an organic solvent such as ethanol, toluene, ketones, and esters can be used.

  The film can be formed from a paste-like composition by using, for example, a coating method such as roller, brush, spray, dipping, or a known printing method such as silk screen printing.

  The coating is formed on one side or both sides of the aluminum-based substrate. The thickness of the coating in the case of forming on one side of the aluminum-based substrate is preferably set so that the thickness of the weld layer obtained after welding described later is 1.5 μm or more and 150 μm or less, and is 1.5 μm or more and 50 μm or less. It is more preferable to set so that. On the other hand, when it forms on both surfaces of an aluminum-type base material, it is preferable to arrange | position a film | membrane symmetrically on both sides of a base material, and it sets so that the total thickness of the welding layer obtained after the below-mentioned welding may be 3 micrometers or more and 300 micrometers or less. It is preferable that the thickness is set to be 3 μm or more and 100 μm or less.

  Prior to the heat treatment in the second step described later, the film may be dried at a temperature of 20 ° C. or higher and 300 ° C. or lower or degreased as necessary.

(Second step)
In the second step, the aluminum-based particles are welded by heat-treating the film.

  The heat treatment temperature may be a temperature at which aluminum-based particles contained in the film are welded, and is usually preferably 560 ° C. or higher and 660 ° C. or lower, more preferably 570 ° C. or higher and 650 ° C. or lower, more preferably 580 ° C. or higher and 640 ° C. or lower. The temperature is most preferred.

  The heating time (holding time at the above temperature) varies depending on the heating temperature, but can usually be determined appropriately within a range of about 5 hours to 24 hours. The heating atmosphere is not particularly limited, and may be any of a vacuum atmosphere, an inert gas atmosphere, an oxidizing gas atmosphere (air), a reducing atmosphere, and the like, and particularly a vacuum atmosphere or a reducing atmosphere. Is preferred. Also, the pressure condition may be normal pressure, reduced pressure or increased pressure. When the heating temperature is less than 560 ° C., particle welding does not proceed and the strength of the welded layer may be weakened. If the temperature exceeds 660 ° C., the particles may melt excessively, and the resin may not sufficiently penetrate into the welded layer in the third step.

  In addition, it is preferable that the film | membrane obtained at the 1st process is degreased beforehand prior to the 2nd process as mentioned above. The degreasing treatment (heat treatment) is preferably performed at a temperature range of 200 ° C. to 450 ° C. and a holding time of 5 hours or more. Such degreasing treatment can sufficiently remove unnecessary solvent and binder components.

  The heating atmosphere for the degreasing treatment is not particularly limited, and may be any of a vacuum atmosphere, an inert gas atmosphere, or an oxidizing gas atmosphere, for example. The pressure condition may be normal pressure, reduced pressure, or increased pressure. In addition, although the sintering in high temperature heating was mentioned here as a method of welding aluminum type particle | grains, it is not limited to this. For example, it is possible to adopt a method in which electricity is applied by resistance heating and a method in which particles are welded in a semi-molten state using a laser beam or a plasma flame.

(Third step)
In the third step, a resin layer fixed in a state of covering the aluminum-based particles is formed.

  The resin component and the optional additive constituting the resin layer are as described in the column of the laminated structure. The resin composition for forming the resin layer contains a solvent such as ethanol, cyclohexane, toluene, acetone, IPA, MEK, propylene glycol, hexylene glycol, butyl diglycol, pentamethylene glycol, normal pentane, normal. An organic solvent such as hexane, hexyl alcohol, N-methyl-2-pyrrolidone can be appropriately selected.

  The method for applying the resin composition so as to cover the weld layer is not particularly limited, but for example, it is applied by roll coating, gravure coating, die coating, dip coating, knife coating, reverse roll coating, spray coating, or other coating methods. The method of printing is mentioned. Further, a T-die extruder, a co-extruder, an extrusion laminating machine, an extrusion coater machine, an injection molding machine, an in-mold molding machine, or the like may be used.

Dried adhesion amount of the resin composition (weight of the resin layer) may be a 0.1 g / ^{m 2} or more 10000 g / ^{m 2} or less, preferably not more 0.5 g / ^{m 2} or more 100 g / ^{m 2} or less, still more preferably 1 g / ^{m 2} or more 50 g / ^{m 2} or less. In addition, since a part of the resin layer is in a form that penetrates or bites into the weld layer of the aluminum-based particles, it is difficult to accurately measure the thickness of the resin layer, but the thickness of the thickest part is 0.2 μm. It is about 10 cm or less.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.
(Preparation of adhesive strength sample)
A sample having a configuration of “first aluminum foil (1) / adhesive / second aluminum foil (2)” was prepared for evaluation of adhesive strength.

  The inner surfaces of the aluminum foil (1) and the aluminum foil (2) are surface-treated as necessary. An epoxy adhesive was used as the adhesive, and an evaluation sample was prepared by a dry laminating method so that the thickness of the adhesive layer after drying was about 15 μm. For the thickness of the adhesive layer, the thickness after drying was measured at five points by cross-sectional observation, and an average value was adopted. When measuring the thickness, if anodized aluminum foils are bonded together, measure the thickness from the anodized surface layer to the opposite anodized film, and if aluminum foil welded aluminum foils are bonded together, from the aluminum powder welded layer surface layer The thickness up to the surface layer of the opposing aluminum powder weld layer was measured. When the surface treatment was not performed, the thickness from one aluminum foil surface to the opposing aluminum foil surface was measured.

(Adhesive strength evaluation)
The sample for adhesive strength evaluation was cut into a strip shape having a width of 10 mm and a length of 200 mm, and then the aluminum foil (1) on one side in the length direction was constituted by aluminum foil (1) / adhesive / aluminum foil (2). After peeling about half in the length direction, after fixing the sample other than the peeled portion to the measuring jig, the peeled aluminum foil (1) was pulled to measure the adhesive strength. The measuring instrument used was a Toyo Seiki strograph. The measurement conditions were a peel angle of 90 ° and the strength when peeled at a constant speed (100 mm / min).

Comparative Example 1
A 150 μm-thick aluminum foil (JIS 1N30, hard) was prepared, and the adhesive strength measurement of a laminated structure of aluminum foil / adhesive / aluminum foil was taken as Comparative Example 1. At the time of measuring the adhesive strength, since the stiffness of the aluminum foil affects the adhesive strength at the peeling angle of 90 °, the same heat treatment as in Example 1 including the degreasing treatment was performed to obtain the same softened state.

Comparative Example 2
An aluminum foil obtained by treating a 150 μm-thick aluminum foil (JIS 1N30, hard) with a 1.5 μm-thick anodized alumite film on both sides was obtained with a prescription for improving the adhesive strength. As in Comparative Example 1, the same heat treatment as in Example 1 was performed including the degreasing step to obtain the same softened state. Although we were anxious about cracking due to the thermal expansion difference of the softening treatment, it was confirmed with a scanning electron microscope that the alumite film was not cracked. The result of the adhesion strength of the laminated structure of aluminum foil (alumite treated surface) / adhesive / (alumite treated surface) aluminum foil was defined as Comparative Example 2. As the thickness of the alumite film becomes thicker, the flexibility is impaired. Therefore, a foil that has produced an alumite film that is as thin as possible at a level that has an effect of improving the adhesive strength was selected.

Example 1
200 parts by mass of aluminum powder (aluminum purity 99% by mass) having an average particle diameter D ₅₀ of 5.0 μm is mixed with 130 parts by mass of a cellulose-based binder (2.5% by mass is a resin component), and the solid content is 61.6% by mass. A coating solution was obtained. This coating solution was applied to one side of a 150 μm thick aluminum foil (1N30, hard) using a bar coater so that the thickness after welding was 10 μm and dried. Next, the aluminum foil which welded aluminum powder was produced by degreasing | defatting at 250 degreeC and baking for 10 hours at the temperature of 640 degreeC in argon gas atmosphere. The adhesive strength result of the laminated structure of aluminum foil (aluminum powder welded surface) / adhesive / (aluminum powder welded surface) aluminum foil was taken as Example 1. The measurement of the average particle size D ₅₀ of the aluminum powder was carried out using a particle size distribution analyzer (Nikkiso Co., Ltd. Microtrac model number MT3300EXII).

  Table 1 shows the adhesive strength and strength improvement rate of Comparative Examples 1 and 2 and Example 1. The strength improvement rate is an index for Comparative Example 1. From this result, it was found that the adhesive strength was untreated aluminum foil <anodized aluminum foil <aluminum powder welded aluminum foil, and the effect of improving the adhesive strength of the laminated structure having aluminum powder welded was the highest.

  FIG. 1 shows a cross-sectional photograph of the laminated structure produced in Example 1. By welding the aluminum powder, gaps are formed between the aluminum particles and between the aluminum particles and the aluminum foil, and the gap is impregnated with the adhesive. Therefore, it is considered that when the substrate is peeled off, the gap is entangled three-dimensionally with respect to the adhesive, and it is difficult to peel off and the adhesive strength is improved.

  The photograph of the peeling interface after peeling the laminated structure produced in Example 1 in FIG. 2 is shown. The peeling interface when the laminated structure of Example 1 is peeled is between the adhesive layer (resin layer) and the aluminum powder weld surface. From FIG. 2, it can be seen that the adhesive is broken on the surface of the aluminum powder welded layer. The laminated structures of Comparative Examples 1 and 2 were peeled off at the aluminum foil interface and the alumite treatment film interface, respectively. On the other hand, the aluminum powder welded aluminum foil is peeled off at the interface of the aluminum welded surface layer as in the comparative example, but at the same time, the adhesive layer impregnated in the welded layer and the adhesive layer above the welded layer are separated from each other. It peels off in a cut shape. Moreover, since it cannot confirm that the aluminum powder of a welding layer has fallen, it turns out that it has welded in the level which can fully endure the adhesive strength of an adhesive agent.

  From the above, the effect of improving the contact area between the adhesive and the base material due to the uneven shape of the aluminum powder welded layer, and the welding force effect that can sufficiently withstand the force that the adhesive itself peels off during peeling, It is considered that the strength improvement rate was higher than that of the comparison. From this result, it is expected that the stronger the cohesive strength of the adhesive, the greater the effect improvement. This is particularly effective for applications that have been a problem of peeling at the aluminum interface.

  Furthermore, since the said base material can also perform well-known surface roughening processes, such as an etching, the further improvement of adhesive strength can be anticipated by adding the surface area expansion effect.

  Below, the further improvement examination of adhesive strength was performed. Taking the laminated structure of Example 1 as an example, the effect of changing the aluminum powder particle size without changing the post-weld thickness 10 μm of the aluminum powder welded layer was investigated.

Example 2
The adhesive strength of the laminated structure in which the aluminum powder used in Example 1 was changed to an aluminum powder having an average particle diameter D _{50 of} 3.0 μm was measured.

Example 3
The aluminum powder used in Example 1 was changed to an aluminum powder having an average particle diameter D _{50 of} 9.0 μm, and the adhesive strength of the laminated structure was measured.

Table 2 shows the results of Examples 2 and 3. From this result, the strength tends to increase as the aluminum powder average particle diameter D ₅₀ increases, and as a result, the strength of the aluminum foil on which 9.0 μm aluminum powder is welded is the highest. Compared to the untreated foil, a strength improvement effect of about twice was obtained.

  Next, the aluminum powder particle size was unified to 5.0 μm, and the effect of changing the thickness of the aluminum powder welded layer was examined.

Example 4
In the laminated structure of Example 1, the adhesive strength of the laminated structure in which the aluminum weld layer thickness was changed from 10 μm to 5 μm was measured.

Example 5
In the laminated structure of Example 1, the adhesive strength of the laminated structure in which the aluminum weld layer thickness was changed from 10 μm to 20 μm was measured.

Example 6
In the laminated structure of Example 1, the adhesive strength of the laminated structure in which the aluminum weld layer thickness was changed from 10 μm to 30 μm was measured.

  The verification results of Examples 4 to 6 are shown in Table 3. From this result, when the thickness of the aluminum powder welded layer was equal to the aluminum powder particle size, the effect of improving the strength was reduced. Further, it was found that the strength is improved by increasing the thickness, but the strength does not change from a certain thickness. In the case of the same thickness as the aluminum powder particle size, the area in contact with the adhesive is larger than the untreated aluminum foil, so there is an effect of improving the adhesive strength, but the area where the adhesive is entangled three-dimensionally decreases, It is considered that the strength improvement effect due to the tearing effect of the adhesive was reduced. Nevertheless, since it showed higher strength than the alumite-treated aluminum foil, the thickness of the aluminum powder welded layer can be properly used depending on the required performance and application.

Next, the examination which changed aluminum foil thickness was carried out. The aluminum powder particle size D ₅₀ was 5.0 μm, and the thickness of the aluminum powder welded layer was unified to about 10 μm.

Example 7
With the configuration of 20 μm aluminum (aluminum powder welded surface) / adhesive / (aluminum powder welded surface) 20 μm aluminum foil, one 20 μm aluminum foil side was pulled to measure the adhesive strength. At the same time, the strength of untreated aluminum foils not subjected to powder welding was also measured and compared.

Example 8
The 50 μm aluminum (aluminum powder welded surface) / adhesive / (aluminum powder welded surface) 50 μm aluminum foil was used, and one 50 μm aluminum foil side was pulled to measure the adhesive strength. At the same time, the strength of untreated aluminum foils not subjected to powder welding was also measured and compared.

Example 9
The 120 μm aluminum (aluminum powder welded surface) / adhesive / (aluminum powder welded surface) 120 μm aluminum foil was used, and one 120 μm aluminum foil side was pulled to measure the adhesive strength. At the same time, the strength of untreated aluminum foils not subjected to powder welding was also measured and compared.

Example 10
The 120 μm aluminum (aluminum powder welded surface) / adhesive / (aluminum powder welded surface) 350 μm aluminum foil was pulled, and the 120 μm aluminum foil side was pulled to measure the adhesive strength. At the same time, the strength of untreated aluminum foils not subjected to powder welding was also measured and compared.

Example 11
120 μm aluminum (aluminum powder welded surface) / adhesive / (aluminum powder welded surface) With a structure of 1000 μm aluminum plate, the 120 μm aluminum foil side was pulled to measure the adhesive strength. At the same time, the strength of untreated aluminum foils not subjected to powder welding was also measured and compared.

  Table 4 shows the results of Examples 7 to 11. In Examples 7 and 8, only the aluminum welded aluminum foil laminated structure broke the material, while the untreated product did not break the material, and the adhesive strength could be measured. The improvement effect is clear from this result. When an aluminum foil having a thickness that does not break the foil was selected and the adhesive strength was compared in the same manner, the effects of improving the adhesive strength were also confirmed in Examples 9-11. At the same time, Examples 10 and 11 in which the thickness of the surface opposite to the aluminum foil on the pulling side was increased were the same as in Example 9. A laminated structure bonded with an adhesive usually peels from a weak layer. However, in Examples 9, 10 and 11, the adhesive was peeled off at the interface on the side where the aluminum foil was pulled, and no peeling occurred on the other aluminum powder welded aluminum substrate side. Therefore, it is considered that the adhesive strength of the thick aluminum welding layer is also improved. When the aluminum foil is thick, the stiffness becomes stronger, so it is difficult to pull the foil itself. From these results, the interfacial strength (adhesion strength) between the aluminum-based substrate and the aluminum-based particle welding layer is sufficiently higher than the adhesion strength between the aluminum-based particle welding layer and the resin layer (adhesive layer). I understand.

  From the above, the thickness of the aluminum base material such as an aluminum foil and a plate is widely applied, and it can be developed for uses that need to improve the strength of the interface between the aluminum and the resin.

  Next, the flexibility of the substrate was examined.

  After the laminated structures used in Comparative Examples 1 and 2 and Example 3 were bent at 180 ° with fingers, the adhesive layer peeling state of the bent portion when the original shape was returned was compared.

  The results of the flexibility test are shown in Table 5. In the case of the aluminum powder welded aluminum foil, the adhesive layer did not float at the bent portion, but the untreated aluminum foil and the anodized aluminum foil were confirmed to float. Cross-sectional photographs of the bent portion relating to the anodized aluminum foil and the aluminum powder welded aluminum foil are shown in FIGS. 3, 4 and 5.

  From the observation result of the cross-sectional photograph, the laminated structure of Comparative Example 2 has a floating adhesive layer, whereas the laminated structure of Example 3 has no floating. Since it can be confirmed from the enlarged photograph of the floating part in FIG. 5 that the alumite film is cracked, it is considered that the film cracking triggered the float. On the other hand, in the laminated structure of Example 3, the adhesive was firmly caught against the stress applied when the three-dimensional structure of the aluminum powder welded layer was deformed, and no floating occurred. The reason why the float occurred in Comparative Example 1 is considered that the float occurred because the adhesive strength at the adhesive interface was weaker than the stress applied to the bending deformation. In addition, although the photograph was not image | photographed, as a result of implementing the bending test similar to the above also in the laminated structure of Example 1, 2, 4-9, the floating of the bending part did not generate | occur | produce like Example 3. . This result clarified two characteristics that the aluminum powder welded aluminum foil has flexibility and also improved adhesive strength. Therefore, it can be used for products that are subject to deformation and processing.

  Next, heat resistance was examined.

  The adhesive strength of the laminated structure subjected to heat treatment for 10 days in an atmosphere at 166 ° C. was evaluated. The results are shown in Table 6.

  The strength reduction rate is a numerical value indicating the strength after heat treatment as a percentage with respect to the initial stage. From this result, it was found that the untreated aluminum foil has a clear superiority and has heat resistance equal to or higher than that of the anodized aluminum foil. The main reason for the decrease in strength is the deterioration of the adhesive. The strength reduction rate is larger as the initial adhesive strength is weaker. Conversely, when the initial adhesive strength is high, the influence of adhesive deterioration can be reduced.

  From the above, it is considered that the present invention can be applied to applications that require heat resistance.

  In addition, by using a base material in which aluminum powder is welded on both sides of an aluminum base material, it can be expanded to applications that require heat dissipation, such as electronic circuit boards, and one side has improved adhesive strength. Moreover, the other surface is a surface area expansion effect by aluminum powder welding, and can provide a laminate having improved adhesive strength and good heat dissipation.

1. 1. Aluminum foil 2. Welded layer of aluminum-based particles 3. Adhesive layer 4. Aluminum foil Anodized layer6. Adhesive layer

Claims (4)

  A laminated structure comprising: an aluminum-based substrate; aluminum-based particles welded to at least a part of the surface of the aluminum-based substrate; and a resin layer fixed in a state of covering the aluminum-based particles. A first structure comprising a first aluminum-based substrate and first aluminum-based particles welded to at least part of the surface of the first aluminum-based substrate;
A second aluminum substrate and a second structure composed of second aluminum particles welded to at least part of the surface of the second aluminum substrate;
The first structure and the second structure are laminated via a resin layer,
The resin layer is a laminated structure that is fixed in a state of covering both the first aluminum-based particles and the second aluminum-based particles. The average particle diameter _{D 50} is 1.5μm or more 15μm or less, the laminated structure according to claim 1 or 2 of the aluminum-based particles. A method of manufacturing a laminated structure,
(1) a first step of forming a film of a composition containing aluminum-based particles on at least a part of the surface of an aluminum-based substrate;
(2) a second step of welding the aluminum-based particles by heat-treating the film;
(3) a third step of forming a resin layer fixed in a state of covering the aluminum-based particles;
In order.