JP7115196B2 - Adhesive bonded structures and automotive parts - Google Patents

Description

The present invention relates to adhesive bonded structures and automotive parts.

In the industrial field of transportation equipment such as automobiles, the application of adhesives in joining members is increasing for purposes such as improving body rigidity, assisting fracture of welded joints, and joining dissimilar materials. The use of adhesives to join members together is expected to significantly improve performance, so it is important as a means of reducing the weight of vehicle bodies. For this reason, in developing an adhesive joint structure using an adhesive between metal members or between a metal member and another material as a vehicle body part, various studies have been conducted with the aim of improving the joint strength between members. ing.

For example, in Patent Document 1 below, an aluminum alloy material in which a predetermined oxide film is provided on the surface of an aluminum alloy base material and a film having a siloxane bond is provided on the oxide film is used. Techniques have been proposed for bonding such aluminum alloy materials to each other or to other members via an adhesive resin.

Further, in Patent Document 2 below, a chemically treated metal plate having a chemically treated film containing a lubricant having a water-soluble resin and a carbon-oxygen bond formed on the surface of a metal substrate is used, and such a chemically treated metal plate and a resin layer are used. A technique has been proposed in which the two are joined via an adhesive layer.

WO2016/076344 WO2017/169571

By the way, when an adhesive is applied, deterioration of the adhesive (lower adhesion) inevitably lowers the performance of the parts. This point applies to both the techniques disclosed in Patent Document 1 and Patent Document 2 above. For this reason, it is difficult to guarantee the application of the adhesive for a long period of time in the actual environment, and depending on the part, there are cases where the application is restricted or the design is made in anticipation of deterioration.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to manufacture by bonding a metal member and another member with an adhesive, and to achieve excellent adhesion durability. An object of the present invention is to provide an adhesive bonding structure and an automobile part.

The present inventors have investigated the cause of the deterioration of the adhesion between the metal member and the adhesive layer, and found that the cause is the intrusion of water into the interface between the metal member and the adhesive layer. I pinpointed it. In view of this, the present inventors investigated the relationship between the adhesive used and water entering the adhesive interface in order to suppress the intrusion of water into the adhesive interface between the metal member and the adhesive layer. As a result, by forming the adhesive layer using an adhesive that uses a specific resin, it is possible to more reliably suppress the intrusion of water into the adhesive interface between the metal member and the adhesive layer, thereby improving the adhesion durability. The present inventors have found that the properties are improved, and have conceived the present invention.
The gist of the present invention completed based on the above knowledge is as follows.

(1) Adhesion that comprises a first member having a metal portion, a second member, and an adhesive layer that joins the first member and the second member, and that constitutes the adhesive layer The resin of the agent is a phenoxy resin, the first member further has a coating portion disposed on at least part of the surface of the metal portion, and the coating portion has a glycidoxy group or a mercapto group. An organic coating portion containing Si element derived from an organic silane compound and containing one or more of water-based polyurethane resin, epoxy resin, and polyester resin, wherein an arbitrary portion of the interface between the metal portion and the coating portion is When the film portion is analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) while argon sputtering is performed from the adhesive layer side toward the metal portion side so as to contain Si—O—Me A peak corresponding to a bond (Me: metal element) was observed, and the count number indicating the Si—O—Me bond was 15 or _more ^. , the acceleration voltage is 30 kV, the sputtering speed is about 80 nm/min (in terms of SiO ₂ ), and the measurement area is 50 μm×50 μm .
( 2 ) The film portion has a structure in which resin particles containing one or more of water-based polyurethane resin, epoxy resin, and polyester resin are dispersed in the film portion, and the average particle diameter of the resin particles is , 20 nm or more and less than 200 nm, and the resin particles occupy 20% or more and less than 80% of the cross-sectional area of the film portion in a cross section along the thickness direction of the film portion. body.
( 3 ) The adhesive bonding structure according to (1) or (2) , wherein the coating portion has an average thickness of 0.2 μm or more and 1.5 μm or less per one side of the first member.
( 4 ) The adhesive bonding structure according to any one of (1) to ( 3 ), wherein the metal portion is made of steel.
( 5 ) The adhesive bonding structure according to any one of (1) to ( 4 ), wherein the metal portion is a zinc-based plated steel sheet.
( 6 ) The adhesive bonding structure according to any one of (1) to ( 5 ), wherein the metal part is a galvannealed steel sheet having a tensile strength of 590 MPa or more.
( 7 ) The first member and the second member are bonded by bonding not depending on the adhesive layer, in addition to bonding via the adhesive layer, (1) to ( 6 ) An adhesive bond structure according to any one of the preceding claims.
( 8 ) The adhesive bonding structure according to ( 7 ), wherein the second member has a metal portion, and the bonding that does not rely on the adhesive layer is spot welding.
( 9 ) An automotive part comprising the adhesive bonding structure according to any one of (1) to ( 8 ).

As described above, according to the present invention, it is possible to provide an adhesively bonded structure and an automobile part which are manufactured by bonding a metal member and another member with an adhesive and which are excellent in bonding durability.

1 is a schematic perspective view of an adhesive bonded structure according to an embodiment of the invention; FIG. 2 is a partially enlarged cross-sectional view of an adhesive bond region of the adhesive bond structure shown in FIG. 1; FIG. 2 is a partially enlarged cross-sectional view of another example of the adhesive bonding region of the adhesive bonding structure shown in FIG. 1; FIG. FIG. 10 is a partially enlarged cross-sectional view for explaining an adhesive region of an adhesively bonded structure according to a modified example of the present invention; FIG. 11 is a schematic perspective view of an adhesive bonded structure according to another modification of the invention; FIG. 11 is a schematic perspective view of an adhesive bonded structure according to another modification of the invention; FIG. 11 is a schematic diagram illustrating the bonding state of an adhesive bonding structure according to another modified example of the present invention;

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

(Regarding the configuration of the adhesive bonding structure)
1 is a schematic perspective view of an adhesive bonding structure according to an embodiment of the present invention, FIG. 2 is a partially enlarged sectional view of an adhesive bonding region of the adhesive bonding structure shown in FIG. 1, and FIG. 2 is a partially enlarged cross-sectional view of another example of the adhesive bonding region of the adhesive bonding structure shown in FIG. 1; FIG.

The adhesive bond structure 1 shown in FIG. 1 has a first member 2 and a second member 3 . The first member 2 is a so-called hat-shaped metal member. The second member 3 has a shape along the inner side of the web portion of the first member 2, and attaches to the first member 2 via the adhesive layer 4 in the adhesive region 5 inside the web portion. is joined to

In order to facilitate the explanation of the configuration of the adhesively bonded structure according to the present invention, it is assumed in FIG. 1 that the first member 2 is of a hat type. Each member constituting the adhesive bonding structure in the present invention is not limited to the shape shown in the drawings. In addition, in the present invention, any member to be joined via the adhesive layer may be a metal member, but in the following description, as an example, the first member 2 and the second member 3 are A case where both are metal members having a metal portion will be described. The configuration of the bonding region 5 will be described below with reference to FIGS. 2 and 3. FIG.

<Regarding the first member 2>
The first member 2 is a metal member as described above, and has a metal portion 21, for example, as shown in FIG. is joined to the member 3 of the Further, in the present embodiment, the first member 2 has, in addition to the metal portion 21, a film portion 22 formed on at least a part of the surface of the metal portion 21, as shown in FIG. preferably.

<<Metal part 21>>
Examples of materials for the metal portion 21 include iron, titanium, aluminum, magnesium, and alloys thereof. Examples of alloys include iron-based alloys (including stainless steel), Ti-based alloys, Al-based alloys, and Mg alloys. The material of the metal portion 21 is preferably a steel material (steel material), an iron-based alloy, titanium, or aluminum, and more preferably a steel material having a higher tensile strength than other metals. Examples of such steel materials include steel materials standardized by the Japanese Industrial Standards (JIS), etc. Carbon steel, alloy steel, high-tensile steel, etc. used for general structures and machine structures. can be done. Specific examples of such iron and steel materials include cold-rolled steel, hot-rolled steel, hot-rolled steel plate for automobile construction, hot-rolled high-strength steel plate for automobile processing, cold-rolled steel plate for automobile construction, Examples include cold-rolled high-strength steel sheets for automotive processing, and high-strength steel materials generally called hot stamp materials that are quenched during hot working. In the case of steel materials, the ingredients are not particularly specified, but in addition to Fe and C, Si, Mn, S, P, Al, N, Cr, Mo, Ni, Cu, Ca, Mg, Ce, Hf, La, Zr , Sb can be added. One or more of these additive elements can be appropriately selected in order to obtain the desired material strength and moldability, and the amount of addition can be adjusted as appropriate.

Further, if the metal portion 21 is made of an aluminum alloy, the weight of the member can be reduced, which is preferable. As the aluminum alloy, one or more of Si, Fe, Cu, Mn, Mg, Cr, Zn, Ti, V, Zr, Pb, and Bi are added to aluminum. Generally known ones such as the described 1000 series, 2000 series, 3000 series, 4000 series, 5000 series, 6000 series, and 7000 series can be used. The 5000 series, 6000 series, and the like, which have strength and moldability, are suitable. As the magnesium alloy, one or more of Al, Zn, Mn, Fe, Si, Cu, Ni, Ca, Zr, Li, Pb, Ag, Cr, Sn, Y, Sb and other rare earth elements are added to magnesium. Commonly known materials such as Al-added AM described in ASTM standards, Al- and Zn-added AZ, and Zn-added ZK can be used. In addition, when the metal part 21 is plate-shaped, these may be shape|molded.

Any surface treatment may be applied to the steel material. Here, the surface treatment includes, for example, various plating treatments such as zinc-based plating, aluminum-based plating, and tin-based plating, chemical conversion treatments such as zinc phosphate treatment, chromate treatment, and chromate-free treatment, and physical treatments such as sandblasting. Examples include, but are not limited to, chemical surface roughening treatments such as thermal or chemical etching. In addition, multiple types of surface treatments may be applied. As the surface treatment, it is preferable that a treatment for the purpose of imparting at least rust resistance is performed.

Among iron and steel materials, plated steel is particularly preferable because of its excellent corrosion resistance. A particularly preferable plated steel material for the metal portion 21 is a zinc-based plated steel plate, a Ni-plated steel plate, or an alloyed Ni-plated steel plate obtained by heat-treating these to diffuse Fe into the Ni-plating to alloy them, an Al-plated steel plate, tin A plated steel plate, a chrome-plated steel plate, etc. are mentioned.

Among the various plated steel sheets as described above, the zinc-based plated steel sheet is excellent in corrosion resistance and can be suitably used as the metal portion 21 . In particular, an alloyed hot-dip galvanized steel sheet in which a steel sheet is galvanized and then alloyed to diffuse iron in the galvanized steel sheet is more suitable because the decrease in strength of the adhesive over time is further suppressed.

By the way, an alloyed hot-dip galvanized steel sheet has a hard alloy layer (generally called a capital Γ layer) in part, and when an adhesive with high bonding strength (for example, a structural adhesive) is used, the The alloy layer may be destroyed and the bond strength may be reduced. However, the present inventors found that if a high-strength alloyed hot-dip galvanized steel sheet is used as the metal part 21, the breakage of the plated alloy layer can be suppressed, and the adhesive strength between the first member 2 and the second member 3 It was found that it is possible to increase

One reason for this is thought to be that the high-strength steel plate is less likely to deform when stress is applied to the adhesive joint structure 1 . That is, in general, when low-strength steel plates are bonded together, the steel plates are deformed in addition to the adhesive when stress such as tensile stress or shear stress is applied to the steel plates. In particular, the deformation concentrates on the edge of the bonding portion. As a result, the plated alloy layer in the deformation concentrated portion is destroyed, and peeling occurs early. On the other hand, when a high-strength steel plate is used, the deformation due to the applied stress is small, so deformation concentration at the end of the bonding portion is prevented. As a result, breakage of the plated alloy layer is suppressed at the bonding site, and stress can be applied to the entire adhesive layer.

Therefore, as the metal portion 21, it is preferable to use a high-strength galvannealed steel sheet, for example, a galvannealed steel sheet having a tensile strength of 590 MPa or more, and a galvannealed steel sheet having a tensile strength of 980 MPa or more. It is more preferable to use Thereby, the bonding strength between the first member 2 and the second member 3 can be further increased. In this case, when the adhesive bonding structure 1 receives stress, the entire adhesive layer 4 can receive the stress, so that it is possible to further obtain the effect of adhesion durability in the present invention, which will be described later. becomes. In addition, the tensile strength of a steel plate can be measured according to JIS Z2241:2011.

The hot-dip galvanized steel sheet and the alloyed hot-dip galvanized steel sheet will be described in detail below.
As the steel plate that is the base material of the hot-dip galvanized steel sheet and the alloyed hot-dip galvanized steel sheet, generally known steel sheets can be used. Examples of such steel plates include hot-rolled mild steel plates and steel strips described in JIS G3131, hot-rolled steel plates and steel strips for automobiles described in JIS G3113, cold-rolled steel plates and steel strips described in JIS G3141, and the like. can be used. It is more preferable to use a high-strength steel sheet that is used for automobile applications, etc., as the steel sheet that serves as the base material. What is more preferable is as described above.

Such a high-strength steel sheet contains 0.050% by mass or more and 0.400% by mass or less of C (carbon), 0.10% by mass or more and 2.50% by mass or less of Si (silicon), and 1.20% by mass of Mn (manganese). It is preferable to have a composition containing not less than 3.50% by mass and the balance being Fe (iron) and impurities. In addition, such a high-strength steel sheet contains C, Si, and Mn in the above contents, and further replaces part of the remaining Fe with P (phosphorus): 0.100% by mass or less, S (sulfur): It is more preferable to contain 0.0100% by mass or less, Al (aluminum): 1.200% by mass or less, and N (nitrogen): 0.0100% by mass or less.

The chemical components (compositions) of steel sheets that constitute such high-strength steel sheets will be described in detail below.

[C: 0.050% by mass or more and 0.400% by mass or less]
C is an essential element for forming hard structures such as martensite, tempered martensite, bainite and retained austenite and improving the strength of the steel sheet. Therefore, in the present embodiment, the C content is preferably 0.050% by mass or more in order to obtain a tensile strength of 590 MPa or more or 980 MPa or more. In order to further increase the tensile strength, the C content is more preferably 0.075% by mass or more. On the other hand, if the C content is excessively increased, the weldability deteriorates, so the C content is preferably 0.400% by mass or less, more preferably 0.300% by mass or less.

[Si: 0.10% by mass or more and 2.50% by mass or less]
Si is an element that secures the elongation of the steel sheet and has the effect of improving the strength without greatly impairing the workability. Therefore, in the present embodiment, it is preferable to set the Si content to 0.10% by mass or more in order to sufficiently ensure workability and strength. In order to more reliably ensure workability and strength, the Si content is more preferably 0.45% by mass or more. On the other hand, if the Si content is excessively increased, the toughness decreases and the workability deteriorates. Therefore, the Si content is preferably 2.50% by mass or less, and 2.30% by mass or less is more preferable.

[Mn: 1.20% by mass or more and 3.50% by mass or less]
Mn is an element having effects equivalent to those of Si. Therefore, in the present embodiment, the Mn content is preferably 1.20% by mass or more in order to sufficiently ensure workability and strength. In order to more reliably ensure workability and strength, the Mn content is more preferably 1.50% by mass or more. On the other hand, if the Mn content is excessively increased, the weldability deteriorates, so the Mn content is preferably 3.50% by mass or less, more preferably 3.30% by mass or less. .

[P: 0.100% by mass or less]
P is an element that embrittles the steel material, and if the content of P exceeds 0.100% by mass, problems such as cracking of the cast slab tend to occur. Therefore, the P content is preferably 0.100% by mass or less, more preferably 0.050% by mass or less. On the other hand, if the P content is less than 0.001%, the manufacturing cost will increase significantly, so the lower limit of the P content is preferably 0.001%.

[S: 0.0100% by mass or less]
Since S is an element that reduces workability such as ductility and bendability, the S content is preferably 0.0100% by mass or less. Moreover, since S is an element that deteriorates weldability, it is more preferable to limit the content to 0.0080% by mass or less. On the other hand, if the S content is less than 0.0001%, the production cost will increase significantly, so the lower limit of the S content is preferably 0.0001%.

[Al: 1.200% by mass or less]
Al is an element that embrittles the steel material, and if the Al content exceeds 1.200% by mass, troubles such as cracking of the cast slab tend to occur. Therefore, the Al content is preferably 1.200% by mass or less. Moreover, since the weldability deteriorates as the Al content increases, the Al content is more preferably 1.100% by mass or less. On the other hand, the effect of the present invention can be exhibited even if the lower limit of the Al content is not particularly set, but Al is an unavoidable impurity present in a trace amount in the raw material, and if the content is less than 0.001%, is accompanied by a significant increase in manufacturing costs. Therefore, the lower limit of the Al content is preferably 0.001% by mass.

[N: 0.0100% by mass or less]
N is an element that forms coarse nitrides and deteriorates workability such as ductility and bendability. If the N content exceeds 0.0100%, workability is significantly deteriorated, so the N content is preferably 0.0100% or less. Also, if the N content is excessive, it may cause blowholes during welding, so the N content should be as small as possible. From these points of view, the N content is more preferably 0.0090% by mass or less. On the other hand, the effect of the present invention can be exhibited even if the lower limit of the N content is not particularly set, but setting the N content to less than 0.0005% by mass causes a significant increase in manufacturing cost. For this reason, the lower limit of the N content is preferably 0.0005% by mass or more.

In addition to the above, the high-strength steel sheet preferably used in the present embodiment may contain other elements as necessary within a range that does not impair the effects of the present invention.

For example, in order to further increase the strength of the steel sheet, at least one of Cr (chromium), Mo (molybdenum), Ni (nickel), or Cu (copper) is added in place of part of the remaining Fe. may be contained with an upper limit of 1.20% by mass.

In addition, in order to further increase the strength of the steel sheet, at least one of Nb (niobium), Ti (titanium), or V (vanadium) is added in a total amount of 0.200 mass instead of part of the remaining Fe. % as the upper limit.

Furthermore, since B (boron) is an element effective in increasing the strength, it may be contained with an upper limit of 0.0075% by mass in place of part of the remaining Fe.

In order to improve the formability of the steel sheet, Ca (calcium), Mg (magnesium), Ce (cerium), Hf (hafnium), La (lanthanum), Zr (zirconium), At least one of Sb (antimony) and REM (rare earth element) may be contained with a total upper limit of 0.1000% by mass.

In the chemical composition of the high-strength steel sheet that is preferably used in the present embodiment, the balance of each element described above is Fe and impurities.

In addition, the aforementioned Cr, Mo, Ni, Cu, Nb, Ti, V, B, Ca, Mg, Ce, Hf, La, Zr, Sb and REM all contain trace amounts of impurities less than the lower limit. It is permissible to

As described above, such a high-strength steel sheet is more suitable when zinc-based plating is applied because it has excellent corrosion resistance. Examples of such galvanized steel sheets include electrogalvanized steel sheets described in JIS G3313 and hot-dip galvanized steel sheets described in JIS G3302.

In the case of an electrogalvanized steel sheet, a steel sheet plated only with zinc (generally called EG) may be used, or a zinc-nickel electroplated steel sheet may be used. In addition, the hot-dip galvanized steel sheet may be generally called GI containing 0.2% Al in the galvanized layer, or generally Zn-Al alloy plated steel sheet containing 1 to 10% Al in the galvanized layer. You may use the steel plate called. Furthermore, a steel plate generally called a Zn-Al-Mg alloy plated steel plate containing Al: 1 to 10% and Mg: 1 to 15% in the galvanized layer may be used.

When such a galvanized layer is an alloyed hot-dip galvanized layer containing 7 to 15% by mass of Fe, 0.05 to 0.5% by mass of Al, and the balance being Zn and impurities, adhesive bonding strength is less likely to decrease over time, which is more preferable. In the present embodiment, the alloyed hot-dip galvanized layer is a plated layer mainly composed of an Fe—Zn alloy in which Fe in steel has diffused during Zn plating due to an alloying reaction. The Fe content is not particularly limited, but if the Fe content in the plating is less than 7% by mass, a soft Zn—Fe alloy is formed on the plating surface, degrading the press formability, and the Fe content is 15% by mass. If it exceeds , a brittle alloy layer develops too much at the base iron interface, and the plating adhesion deteriorates. Therefore, the appropriate Fe content is 7 to 15% by mass. In general, when hot-dip galvanizing is continuously performed, Al is added to the plating bath for the purpose of controlling the alloying reaction in the plating bath. is included. In addition, in the alloying process, the elements added to the steel diffuse at the same time as Fe diffuses, so these elements are also contained in the plating.

An example of a manufacturing method for obtaining the hot-dip galvanized steel sheet as described above is shown below. However, the above-described high-strength hot-dip galvanized steel sheet may be produced using a method other than the production method exemplified below, and the conditions explained below are only suitable ones, and are one example. It's nothing more than

The steel plate used as the base material for such a zinc-based plated steel plate is manufactured by hot-rolling a cast slab, or by hot-rolling, cold-rolling, and then, if necessary, annealing. or More preferably, such annealing is performed by performing a continuous annealing process. Furthermore, such steel sheets can be electroplated in a continuous electroplating line. In the case of a hot-dip galvanized steel sheet, the hot-rolled steel sheet or cold-rolled steel sheet is heated in a continuous coating line and then heated in a reducing atmosphere (nitrogen gas atmosphere containing 1 to 5% hydrogen) (generally, a reducing furnace ) to reduce the oxides on the surface of the steel sheet (generally called the oxidation-reduction method), cool it down, immerse it in a hot-dip zinc-based plating bath, pull it up, and gas-wipe it to reduce the amount of coating. Manufactured by adjustment. Common wiping gases such as air and nitrogen gas can be used as the wiping gas, but nitrogen gas is more preferable because it can suppress oxidation of the plating layer. When manufacturing an alloyed hot-dip galvanized steel sheet, after adjusting the coating amount by gas wiping in such a process, the steel sheet is heated to 400 to 500° C. in an alloying furnace for alloying treatment.

<<Coating part 22>>
As described above, at least part of the surface of the first member 2 preferably has the film portion 22 . That is, it is preferable that the film portion 22 is formed on at least a portion of the surface of the metal portion 21 . When the coating portion 22 is formed, at least a part of the coating portion 22 is in contact with the adhesive layer 4 , and as a result, the first member 2 is attached to the second adhesive layer 4 via the coating portion 22 . is adhered to the member 3 of . The film portion 22 is an organic film portion containing Si element and at least one of water-based polyurethane resin, epoxy resin, and polyester resin. Hereinafter, the configuration of the film portion 22 that is preferably included in the adhesive bonding structure 1 according to this embodiment will be described in detail.

As described above, the coating portion 22 according to the present embodiment contains the Si element and contains one or more of water-based polyurethane resin, epoxy resin, and polyester resin. More specifically, as schematically shown in FIG. 3, at least one of the water-based polyurethane resin, epoxy resin, and polyester resin exists mainly as resin particles 221 in the film portion 22, and Si It has a structure in which such resin particles 221 are dispersed in a compound phase 223 containing elements. The compound phase 223 is preferably a compound phase containing Si element derived from various silane compounds, more preferably a compound phase containing Si element derived from an organic silane compound.

The presence of the compound phase 223 containing the Si element in the film portion 22 forms a primary bond called a Si—O—Me bond with the element forming the metal portion 21 . Here, Me indicates a metal element that is the main component of the metal portion 21 (in other words, a metal element whose content is 50% by mass or more with respect to the total mass of the metal portion 21). For example, when the metal part 21 is a steel material, the above Me is Fe, and when the metal part 21 is an aluminum material, the above Me is Al. By forming such a primary bond, the bonding state between the metal portion 21 and the coating portion 22 becomes stronger, and the adhesion between the metal portion 21 and the coating portion 22 is further improved. As a result, a state in which it is difficult for water to enter the interface between the metal portion 21 and the film portion 22 from the outside can be realized more reliably. Thereby, in the adhesive bonding structure 1 according to the present embodiment, it is possible to further improve the adhesion durability between the metal portion 21 and the film portion 22 .

In the coating portion 22, the resin particles 221 are dispersed in the compound phase 223, and the resin particles 221 contain at least one of water-based polyurethane resin, epoxy resin, and polyester resin. Among these resins, the epoxy resin has a chemical structure similar to that of the phenoxy resin forming the adhesive layer 4 of the adhesive bonding structure 1 according to the present embodiment, as will be described in detail below. Water-based polyurethane resins and polyester resins have high affinity with epoxy resins, and also have high affinity with phenoxy resins forming the adhesive layer 4 of the adhesive bonding structure 1 according to the present embodiment. Therefore, the adhesion at the interface between the coating portion 22 and the adhesive layer 4 is improved by the coating portion 22 containing the resin particles 221 composed of the resin as described above. As a result, a state in which it is difficult for water to enter the interface between the coating portion 22 and the adhesive layer 4 from the outside is more reliably realized. Thereby, in the adhesive joint structure 1 according to the present embodiment, it is possible to further improve the adhesion durability between the film portion 22 and the adhesive layer 4 .

As described above, the film portion 22 is composed of a compound phase containing Si element and an organic resin phase made of a specific resin, so that two interfaces in the film portion 22 (film portion 22 - metal portion 10 interface, film portion 22-adhesive layer 4 interface) is further improved, and the adhesion durability of the adhesive bonding structure 1 can be further improved.

The specific chemical structure of the resin particles 221 is not particularly limited as long as the resin particles 221 are composed of one or more of water-based polyurethane resin, epoxy resin, and polyester resin. For example, epoxy resins and polyester resins may be water-soluble or water-dispersible water-based resins that dissolve or disperse in water, or solvent-based resins that dissolve or disperse in organic solvents. From the point of suitability, it is preferably a water-based resin. Further, the specific chemical structure of the water-based polyurethane resin is not particularly limited as long as it is a water-soluble or water-dispersible water-based resin that dissolves or disperses in water.

Examples of such water-based resins include water-soluble or water-dispersible resins such as polyurethane resins, epoxy resins, polyester resins, and mixed resins of two or more of these resins. When a polyester resin is used, it preferably has a molecular weight of 10,000 to 30,000. If the molecular weight is less than 10,000, it may be difficult to ensure sufficient workability. On the other hand, if the molecular weight exceeds 30,000, the bonding sites of the resin itself are lowered, and it may become difficult to ensure excellent adhesion to the adhesive layer 4 . In addition, when a curing agent such as melamine is used for cross-linking, the cross-linking reaction may not be sufficiently performed, and the performance of the coating portion 22 may be deteriorated. When a urethane resin is used, the form of the polyurethane resin is preferably an emulsion having an emulsion particle size of 10 to 100 nm (preferably 20 to 60 nm). An excessively small emulsion particle size may result in high cost. On the other hand, if the emulsion particle size is excessively large, the gaps between the emulsions become large when formed into a coating film, so the barrier properties of the coating portion 22 may be lowered. Types of polyurethane resins include ether-based, polycarbonate-based, ester-based, and acrylic-graphite-based types. These may be used alone or in combination.

On the other hand, solvent-based resins include polyester resins, epoxy resins, mixed resins of two or more of these resins, and the like.

Here, the resin contained in the coating portion 22 may be a crosslinked resin having a crosslinked structure or a non-crosslinked resin having no crosslinked structure. Therefore, it is preferably a non-crosslinked resin. A water-soluble cross-linking agent is preferable as the cross-linking agent (curing agent) that imparts a cross-linked structure to the resin. Specifically, melamine, isocyanate, silane compounds, zirconium compounds, titanium compounds and the like are preferable as the cross-linking agent.

The amount of the cross-linking agent to be added is preferably 5 to 30 parts by mass with respect to 100 parts by mass of the solid content of the resin. If the amount of the cross-linking agent added is less than 5 parts by mass, the cross-linking reaction with the resin may decrease, resulting in insufficient performance as a coating film. On the other hand, if the amount of the cross-linking agent added is more than 30 parts by mass, the cross-linking reaction proceeds too much, the film portion 22 becomes excessively hard, and workability is lowered. Furthermore, paint stability may be reduced.

The particle shape of the resin particles 221 is not particularly limited. It can be a shape close to a sphere such as a brilliant cut shape, an elongated shape (e.g., rod-like, needle-like, fiber-like, etc.), or a planar shape (e.g., flake-like, flat plate-like, thin plate-like, etc.). .

In the coating portion 22 according to this embodiment, the average particle size of the resin particles 221 is preferably 20 nm or more, for example. By setting the average particle diameter of the resin particles 221 to 20 nm or more, the affinity with the adhesive layer 4 as described above can be more reliably improved. The average particle diameter of the resin particles 221 is more preferably 30 nm or more, and still more preferably 50 nm or more. On the other hand, when the average particle diameter of the resin particles 221 is less than 200 nm, it becomes possible to form a denser resin barrier layer, and the adhesion between the film portion 22 and the adhesive layer 4 is further improved. can be done. The average particle diameter of the resin particles 221 is more preferably 180 nm or less, and still more preferably 150 nm or less.

Here, the “average particle diameter” of the resin particles 221 refers to the average primary particle diameter when the resin particles 221 exist alone in the coating portion 22, and the resin particles 221 are aggregated and exist. When it does, it means the average secondary particle size representing the particle size of the resin particles at the time of agglomeration. It is preferable to obtain the average particle size of the resin particles 221 by the following measurement method.

First, by cutting the portion where the film portion 22 of the adhesive bonding structure 1 is arranged, the cross section is exposed, and the cross section is further polished to form a cross section in the thickness direction of the film portion 22 of the first member 2. Obtain a sample. Next, the film portion 22 portion of the cross-sectional sample is observed with a scanning electron microscope to obtain an observed image of the cross section of the film portion 22 . Several resin particles 221 are arbitrarily selected from the field of view of the observed image, and the length of the long side and the length of the short side of each resin particle 221 are measured. Finally, the average long side length and the average short side length are calculated, and the average long side length and the average short side length are averaged to calculate the average particle size. do.

Note that the numerical value of the average particle size varies slightly depending on the measurement method. For example, in the case of using a particle size distribution meter, it may vary depending on the measurement principle, and in the case of image analysis, it may vary depending on the image processing method. However, the range of resin particle size specified herein takes such variations into account. Regardless of the average particle size obtained by any method, the above effects can be stably obtained within the range defined in the present specification.

Here, whether or not the film portion 22 according to the present embodiment contains at least one of polyurethane resin, epoxy resin, and polyester resin can be determined by the following method.

First, a portion of the adhesive structure 1 where the film portion 22 is disposed is obliquely cut to expose its cross section, and the cross section is further polished to obtain the thickness of the film portion 22 of the first member 2. A cross-sectional sample in the direction is obtained. Next, the film portion 22 portion of the cross-sectional sample was analyzed with a microscopic IR spectrometer, and vibration peaks derived from polyurethane resin, epoxy resin, and polyester resin were observed in the obtained infrared absorption spectrum of the film portion 22. It is possible to make a determination based on whether or not there is. Specifically, in the obtained infrared absorption spectrum, when a peak attributed to a C—N group near 1550 cm ⁻¹ and a peak attributed to a C═O group near 1740 cm ⁻¹ are observed. , determined to contain an aqueous polyurethane resin, and when a peak attributed to an epoxy group near 830 cm ^-1 is observed, it is determined to contain an epoxy resin, and C=O groups near 1720 to 1740 cm ^-1 If the assigned peak is observed, it can be determined to contain a polyester resin. As long as the film portion 22 can be sufficiently enlarged, the cutting angle in the oblique cutting may be any angle.

In addition, in a cross section along the thickness direction of the coating portion 22 according to the present embodiment (for example, a cross section as shown in FIG. 3), the resin particles 221 can occupy 20% or more of the cross-sectional area of the coating portion 22. preferable. That is, in the cross section, the area ratio of the resin particles 221 is preferably 20% or more with respect to the cross-sectional area of the film portion 22 . By setting the area ratio of the resin particles 221 to 20% or more, it is possible to more reliably improve the affinity with the adhesive layer 4 as described above. The area ratio of the resin particles 221 in the cross section of the coating portion 22 is more preferably 30% or more, and still more preferably 40% or more. On the other hand, since the area ratio of the resin particles 221 in the cross section is less than 80%, the adhesiveness between the coating portion 22 and the metal portion 21 is reliably maintained, and the adhesion between the coating portion 22 and the adhesive layer 4 is maintained. can further improve the affinity of The area ratio of the resin particles 221 in the cross section of the coating portion 22 is more preferably 70% or less, and even more preferably 60% or less.

The area ratio of the resin particles 221 in the cross section of the coating portion 22 and whether or not the coating portion 22 contains the Si element are preferably determined by the following measurement methods. First, by cutting the portion where the film portion 22 of the adhesive bonding structure 1 is arranged, the cross section is exposed, and the cross section is further polished to form a cross section in the thickness direction of the film portion 22 of the first member 2. Obtain a sample. Next, a thin film sample for TEM observation is prepared from the film portion 22 of the cross-sectional sample by the FIB-microsampling method and the cryo-FIB-microsampling method, and is obtained using an FE-TEM capable of analyzing a minute area. Observe the thin film sample for TEM observation. EDS analysis (elemental mapping) is performed on arbitrary three points near the interface between the metal portion and the adhesive layer to obtain elemental maps of C, O, and Si. After that, the obtained element map is binarized for C and other elements to calculate the average particle diameter and area ratio of the resin particles in the film portion.

In addition, the compound phase 223 according to the present embodiment is not particularly limited as long as it is composed of a silane compound containing Si element, and it is also possible to use a general inorganic silane compound such as colloidal silica. However, it is preferred to use an organosilane compound, for example a silane compound having a glycidoxy group or a mercapto group. By using an organic silane compound having a glycidoxy group or a mercapto group as the silane compound, it is possible to realize the Si—O—Me bond formation state as described in detail below in a more reliable and preferable state. As a result, it becomes possible to more reliably achieve long-term adhesion durability. In addition to organosilane compounds having a glycidoxy group or a mercapto group, organosilane compounds having, for example, an amino group, a vinyl group, a methacryl group, or the like may also exist in the organosilane compound, but the present inventors have verified that the As a result, when an organic silane compound having an amino group, a vinyl group, a methacrylic group, or the like is used, the silane compound and the organic resin phase are formed inside the film portion 22 rather than the reaction at the interface between the metal portion 21 and the film portion 22. It has been found that the reaction with the resin to which the adhesive is applied is further accelerated, making it difficult to obtain long-term adhesion durability. Therefore, it is preferable to use an organic silane compound having a glycidoxy group or a mercapto group from the viewpoint of realizing long-term adhesion durability by preventing penetration of an electrolytic solution such as water. As the organic silane compound having a glycidoxy group or a mercapto group, a commercially available one that satisfies the conditions may be used, or one synthesized by oneself may be used.

Here, in the coating portion 22 according to the present embodiment, the coating portion 22 is argon-sputtered from the adhesive layer 4 side toward the metal portion 21 side so as to include an arbitrary portion of the interface between the metal portion 21 and the coating portion 22 . However, when analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS), it is preferable to obtain the following analytical results. That is, in the TOF-SIMS analysis results, a peak corresponding to the Si—O—Me bond (Me: the metal element forming the metal portion 21) was observed, and the count value indicating the Si—O—Me bond was 15. It is preferable that it is above.

Here, the peak corresponding to the Si—O—Me bond is observed at a characteristic position for each element Me, depending on the specific type of the element Me. For example, when Me=Fe, a typical peak corresponding to the Si—O—Fe bond is the peak observed at the position of mass 100±0.1 in the TOF-SIMS analysis results, and Me=Zn In the case of , a representative peak corresponding to the Si—O—Zn bond is the peak observed at the position of mass 108±0.1 in the TOF-SIMS analysis results. A representative peak corresponding to the O—Al bond is the peak observed at a mass position of 71±0.1 in the TOF-SIMS analysis results.

The results of such analysis show that the generation reaction of the Si—O—Me bond proceeds efficiently at the interface between the metal portion 21 and the coating portion 22, and the interface between the metal portion 21 and the coating portion 22 has a constant This indicates that more than the amount of Si--O--Me bonds are generated. A certain amount or more of Si--O--Me bonds are generated at the interface between the metal part 21 and the film part 22, so that even when the adhesive joint structure 1 is exposed to a moist environment, water will not be absorbed. Intrusion into the interface between the metal portion 21 and the film portion 22 can be prevented, and the adhesion durability over a longer period of time can be maintained.

The count value indicating Si—O—Me bonds as described above is more preferably 20 or more, and still more preferably 30.

The count number of peaks corresponding to Si--O--Me bonds at the interface between the metal portion 21 and the film portion 22 can be measured as follows. First, the bonding joint between the metal part 21 and the film part 22 is cut from the side of the adhesive layer 4 toward the side of the metal part 21 with an inclination of 5 degrees with a slanted cutting device (SAICAS), A sample with an adhesive layer having a thickness of about 1 μm is prepared by using Ar sputtering in combination. A portion where the thickness of the adhesive layer is reduced to about 1 μm is analyzed by TOF-SIMS while argon sputtering is performed from the adhesive layer side toward the metal portion side. After sputtering with an Ar beam from the surface to a certain depth, TOF-SIMS measurement is performed, and similarly, the TOF-SIMS measurement is performed after sputtering in the same manner, and the depth direction distribution is obtained for various elements and bonds. The primary ion species is Au ₃ ⁺ , the acceleration voltage is 30 kV, the sputtering speed is about 80 nm/min (in terms of SiO ₂ ), and the measurement area is 50 μm×50 μm.

Since each ion has a specific mass number, the TOF-SIMS measurement described above measures the depth direction profile of the theoretical mass number of the target Si--O--Me bond. Along with the depth direction profile of the mass corresponding to the Si—O—Me bond, from the respective depth direction profiles of Me ions, which are the main component of the metal part, and C ions, which are the main component of the resin, Me ions The portion from the rising portion of the count value and the falling portion of the count value of C ions to the portion where the count number of C ions becomes almost constant is regarded as the interface portion, and Si—O—Me at the interface portion. Measure counts corresponding to binding.

Note that the area ratio of the resin particles 221 and the count value of Si—O—Me bonds in TOF-SIMS as described above are used as raw materials for the organic resin phase when forming the film portion 22 according to the present embodiment. By appropriately adjusting the selection and content of the material to be used as the raw material of the compound phase and the material to be the compound phase, the desired range can be achieved.

≪Other ingredients≫
The coating portion 22 may contain other additives in addition to the above components. Examples of other additives include well-known additives such as oxide particles, extender pigments, solid lubricants, rust preventives, leveling agents, viscosity imparting agents, pigment anti-settling agents, and antifoaming agents.

<<Average thickness of the film portion 22>>
In the present embodiment, the average thickness of the film portion 22 as described above is preferably 0.2 μm or more per side of the first member 2 (in other words, per side of the metal portion 21). By setting the average thickness per side of the coating portion 22 to 0.2 μm or more, it is possible to more reliably achieve the above-described effects of providing the coating portion 22 . The average thickness per side of the coating portion 22 is more preferably 0.4 μm or more, and still more preferably 0.5 μm or more. On the other hand, by setting the average thickness per side of the coating portion 22 to 1.5 μm or less, it is possible to ensure conductivity to the metal portion 21 through the coating portion 22. For example, through the coating portion 22, Electrodeposition coating can be applied to the metal portion 21, and spot welding can be applied to the metal portion 21 via the film portion 22. The average thickness per side of the coating portion 22 is more preferably 1.2 μm or less, and still more preferably 1.0 μm or less.

Note that the average thickness of the coating portion 22 can be measured as follows. First, by cutting the portion where the film portion 22 of the adhesive bonding structure 1 is arranged, the cross section is exposed, and the cross section is further polished, and a cross-sectional sample in the thickness direction of the film portion 22 of the first member 2 is obtained. get Next, the film portion 22 portion of the cross-sectional sample is observed with a scanning electron microscope to obtain an observation image of the cross section of the film portion 22 . The thickness of the coating portion 22 present in the field of view of the observation image is measured, and the average value is calculated as the average thickness of the coating portion 22 .

A known chemical conversion treatment film may be formed on the portion of the first member 2 that is not in contact with the adhesive layer 4 described above.

<Regarding the second member 3>
In this embodiment, the second member 3 is a metal member and has the metal portion 31 as described above. In addition to the metal portion 31 , the second member 3 preferably has a film portion 32 formed on at least part of the surface of the metal portion 31 .

The configurations of the metal portion 31 and the coating portion 32 can be the same as the configurations of the metal portion 21 and the coating portion 22 of the first member 2, respectively, and are similar to the metal portion 21 and the coating portion 22 of the first member 2. Therefore, detailed description thereof will be omitted below.

<Regarding Adhesive Layer 4>
The adhesive layer 4 is arranged between the first member 2 and the second member 3 in the adhesion region 5 to adhere the first member 2 and the second member 3 together.

The adhesive layer 4 is mainly composed of an adhesive, and the resin constituting the adhesive is a phenoxy resin. Since the phenoxy resin has a molecular structure very similar to that of the epoxy resin, the phenoxy resin has heat resistance equivalent to that of the epoxy resin, and also has good adhesiveness to the metal portion 21 .

In addition, among thermoplastic resins, phenoxy resin has good moldability and excellent adhesiveness with the metal part 21. In addition, by using acid anhydrides, isocyanate compounds, caprolactam, etc. as cross-linking agents, high heat resistance can be obtained after molding. It is also possible to impart properties similar to those of a curable thermosetting resin. Therefore, in the present embodiment, a resin composition containing 50 parts by mass or more of a phenoxy resin with respect to 100 parts by mass of the resin component is used as the resin component of the adhesive constituting the adhesive layer 4 . By using such a resin composition, it becomes possible to firmly join the metal portion 21 . More preferably, the resin composition contains 55 parts by mass or more of the phenoxy resin in 100 parts by mass of the resin component. The form of the adhesive resin composition can be, for example, powder, liquid such as varnish, or solid such as film.

The content of the phenoxy resin can be measured using infrared spectroscopy (IR: InfraRed spectroscopy) as follows, and the content of the phenoxy resin is determined from the target resin composition by infrared spectroscopy. When analyzing, it can be measured by using a general method of infrared spectroscopic analysis such as transmission method or ATR reflection method.

A solidified or cured resin composition is scraped off with a sharp knife or the like to sample the target resin composition. In the transmission method, the KBr powder and the resin composition powder to be analyzed are uniformly mixed and crushed in a mortar or the like to form a thin film, which is used as a sample. In the case of the ATR reflection method, as in the transmission method, powders may be uniformly mixed and crushed in a mortar to prepare a tablet to prepare a sample. The surface of 8 mm) may be scratched with a file or the like, and the powder of the resin composition to be analyzed may be sprinkled and adhered to form a sample. In any method, it is important to measure the background of KBr alone before mixing with the resin to be analyzed. As the IR measurement device, a commercially available general one can be used, and the analysis accuracy is such that the absorbance can be distinguished in units of 1% and the wavenumber can be distinguished in units of 1 cm ⁻¹ . Apparatus is preferable, and examples thereof include FT/IR-6300 manufactured by JASCO Corporation.

When investigating the content of the phenoxy resin, the absorption peaks of the phenoxy resin are present at, for example, 1450 to 1480 cm ⁻¹ , around 1500 cm ⁻¹ , around 1600 cm ⁻¹ . Therefore, the content of the phenoxy resin is calculated based on the previously prepared calibration curve showing the relationship between the absorption peak intensity and the phenoxy resin content, and the measured absorption peak intensity. It is possible to

Here, the "phenoxy resin" is a linear polymer obtained from a condensation reaction between a dihydric phenol compound and epihalohydrin, or a polyaddition reaction between a dihydric phenol compound and a bifunctional epoxy resin, and is amorphous. Thermoplastic resin. A phenoxy resin can be obtained by a conventionally known method in a solution or without a solvent, and can be used in any form of powder, varnish and film. The average molecular weight of the phenoxy resin, in terms of weight average molecular weight (Mw), is, for example, within the range of 10000 or more and 200000 or less, preferably 20000 or more and 100000 or less, more preferably 30000 or more and 80000 or less. is. By setting the Mw of the phenoxy resin within the range of 10,000 or more, the strength of the molded article can be increased, and this effect is further enhanced by setting the Mw to 20,000 or more, further 30,000 or more. On the other hand, by setting the Mw of the phenoxy resin to 200,000 or less, the workability and processability can be improved. In addition, Mw in this specification is a value measured by gel permeation chromatography (GPC) and converted using a standard polystyrene calibration curve.

The hydroxyl equivalent (g/eq) of the phenoxy resin used in the present embodiment is, for example, within the range of 50 or more and 1000 or less, preferably 50 or more and 750 or less, more preferably 50 or more and 500 or less. Within range. By setting the hydroxyl equivalent weight of the phenoxy resin to 50 or more, the number of hydroxyl groups is reduced, which lowers the water absorption rate, so that the mechanical properties of the cured product can be improved. On the other hand, by setting the hydroxyl group equivalent of the phenoxy resin to 1,000 or less, it is possible to suppress the decrease in the number of hydroxyl groups. can be done. This effect is further enhanced by setting the hydroxyl equivalent to 750 or less, further 500 or less.

The glass transition temperature (Tg) of the phenoxy resin is suitable, for example, in the range of 65°C or higher and 150°C or lower, preferably 70°C or higher and 150°C or lower. When the Tg is 65° C. or higher, the flowability of the resin can be suppressed from becoming too large while ensuring the moldability, so the thickness of the adhesive layer 4 can be sufficiently ensured. On the other hand, if the Tg is 150° C. or less, the melt viscosity becomes low, so that the joining process can be performed at a lower temperature. In addition, the Tg of the resin in this specification is measured at a temperature within the range of 20 to 280 ° C. with a temperature increase condition of 10 ° C./min using a differential scanning calorimeter, and is calculated from the peak value of the second scan. It is a numerical value.

Since the phenoxy resin has the glass transition temperature Tg as described above, when the adhesive bonding structure 1 is manufactured by providing the adhesive layer 4 of the phenoxy resin, the adhesive bonding structure 1 can be made to have a glass transition temperature of Tg. By heating to a temperature Tg or higher (for example, 200° C. or higher), the first member 2 and the second member 3 can be easily dismantled. Therefore, it is possible to recycle the first member 2 and the second member 3, which is preferable.

The phenoxy resin is not particularly limited as long as it satisfies the above physical properties, but preferred are bisphenol A type phenoxy resins (for example, Nippon Steel & Sumikin Chemical Co., Ltd. Phenotote YP-50, Phenotote YP-50S, available as Phenotote YP-55U), bisphenol F type phenoxy resin (for example, available as Phenotote FX-316 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), copolymerized phenoxy resin of bisphenol A and bisphenol F (for example, Nippon Steel & Sumitomo Metal YP-70 manufactured by Kagaku Co., Ltd.), brominated phenoxy resins other than the phenoxy resins listed above, phosphorus-containing phenoxy resins, special phenoxy resins such as sulfone group-containing phenoxy resins (for example, phenoxy resins manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. Tote YPB-43C, Phenotote FX293, YPS-007, etc.). These resins can be used individually by 1 type or in mixture of 2 or more types.

The adhesive bonding structure 1 according to one embodiment of the present invention has been described above in detail. According to this embodiment, the first member 2 and the adhesive layer 4 are bonded together by providing the adhesive layer 4 using a phenoxy resin and forming a strong bond between the metal portion 21 and the adhesive layer 4 . and the interface between the second member 3 and the adhesive layer 4 is suppressed, and as a result, deterioration of the adhesive layer 4, deterioration of the first member 2, the second member 3 corrosion is suppressed. Further, by further providing a film portion containing Si element and containing at least one of a water-based polyurethane resin, an epoxy resin, and a polyester resin between the metal portion 21 and the adhesive layer 4, the first member 2 and the adhesive layer 4 and the interface between the second member 3 and the adhesive layer 4 is further suppressed. Corrosion of the member 2 and the second member 3 is further suppressed. For this reason, the adhesive bonding structure 1 is prevented from lowering the adhesive strength. That is, the adhesive joint structure 1 has excellent adhesion durability.

(About modification)
An embodiment of the present invention has been described above. Several variations of the above embodiments of the invention are described below. It should be noted that each modified example described below may be applied to the above-described embodiment of the present invention alone, or may be applied in combination to the above-described embodiment of the present invention. Moreover, each modification may be applied in place of the configuration described in the above embodiment of the present invention, or may be additionally applied to the configuration described in the above embodiment of the present invention. The following description will focus on the differences between the above-described embodiment and each modification, and the description of the same items will be omitted as appropriate.

For example, in the above description, the second member 3 has the film portion 32, but the present invention is not limited to such an example. For example, the second member may not have the film portion 32 described above. FIG. 4 is a partially enlarged cross-sectional view for explaining an adhesive region of an adhesive joint structure according to one modification of the present invention.

An adhesive bonding structure 1A shown in FIG. 4 has a first member 2A and a second member 3A, and the first member 2A and the second member 3A are bonded by an adhesive layer 4A. there is The first member 2A has a metal portion 21A and a coating portion 22A formed on the surface of the metal portion 21A. The coating portion 22A has resin particles 221 and a compound phase 223 .

The second member 3A is a member adhered to the first member 2A via an adhesive layer 4A. And the 2nd member 3A does not have the coating part 32 unlike embodiment mentioned above. In this case, the second member 3A can be made of any material.

For example, as materials that can be used for the second member 3A, in addition to the material of the metal portion 21 described above, a resin material and a fiber reinforced plastic (FRP: Fiber Reinforced Plastics) obtained by incorporating reinforcing fibers into a matrix resin and compounding them are included. ) and ceramic materials. Reinforcing fibers used in fiber-reinforced plastics include glass fibers and carbon fibers.

Even in the above case, the adhesive joint structure 1A has the film portion 22A, so that the adhesive joint structure 1A is superior in adhesion durability as compared with an adhesive joint structure without the film portion 22A.

Moreover, the shape of the adhesively bonded structure according to the present invention is not limited to that of the embodiment described above. The shape of the first member and the second member constituting the adhesively bonded structure according to the present invention can be arbitrarily set, and the bonding portion between the first member and the second member is also an arbitrary portion. can be selected. Furthermore, the adhesive bond structure according to the present invention may have members other than the first member and the second member. 5 and 6 are schematic perspective views of an adhesive joint structure according to another modification of the present invention, and FIG. 7 shows the adhesion state of the adhesive joint structure according to another modification of the present invention. It is a schematic diagram explaining.

The adhesive bonding structure 1B shown in FIG. 5 has a hat-shaped first member 2B and a flat plate-shaped second member 3B. It is adhered to the second member 3B via the agent layer 4 . An adhesive joint structure 1C shown in FIG. 6 has a hat-shaped first member 2C and a hat-shaped second member 3C, which are arranged so that their respective flange portions face each other. The facing flange portions of the first member 2C and the second member 3C are adhered via an adhesive layer 4C to form an adhesion region 5C. Further, in the adhesive bonding structure 1D shown in FIG. 7, the edge of the plate-like portion of the first member 2D is covered with the second member 3D by hemming to form a hem portion. At the hem portion, the first member 2D and the second member 3D are adhered via an adhesive layer 4D.

In any of the modifications shown in FIGS. 5 to 7, a film portion containing resin particles 221 and a compound phase 223 is formed on the surfaces of the first members 2B to 2D in contact with the adhesive layers 4B to 4D. . As a result, the adhesive joint structures 1B to 1D are also excellent in adhesive durability.

In the above description, the first member has the metal portion, but the second member may have the metal portion instead of the first member. As long as the shape of the adhesive joint structure of the present invention is not limited, it is clear that even in such a case, the adhesion durability of the adhesive joint structure is excellent.

Furthermore, in the above-described embodiment, the case where the first member 2 and the second member 3 are adhered only by the adhesive layer 4 has been described, but the present invention is not limited to this, and the adhesive layer Adhesive bonding can be combined with other bonding methods.

A bonding method that can be combined with adhesive bonding is not particularly limited, and any bonding method can be adopted. Specific examples of such bonding methods include fusion bonding, non-fusion bonding, mechanical bonding, and the like.

For fusion bonding, for example, spot welding, arc welding, laser welding, or the like can be used. Fusion bonding can be applied when the first member and the second member have metal parts. The fusion bonding may be performed after removing the adhesive layer, but if the adhesive layer has conductivity, it can be performed without removing the adhesive layer.

Examples of non-melt welding include friction stir welding, diffusion welding, and pressure welding. Examples of mechanical joining include riveting and screw joining.

(About usage)
Next, applications of the adhesive bonding structure according to the present invention will be described. The use of the adhesively bonded structure according to the present invention is not particularly limited, and it can be used as a member of any machine, building, structure, or the like. In particular, the adhesive bonding structure according to the present invention is excellent in water-resistant adhesiveness, and is relatively lightweight due to the use of an adhesive. Therefore, the adhesive bonded structure according to the present invention is suitable for parts for transportation equipment, especially parts for automobiles, which are likely to be placed in an environment where they come into contact with water and which are always required to be lightweight. Accordingly, the invention also relates in one aspect to a motor vehicle component comprising an adhesive bond structure according to the invention.

Automobile parts to which the adhesive joint structure according to the present invention is applied are not particularly limited, but for example, closed cross-section members bonded with flanges (e.g., A pillar, B pillar, side sills, etc.), reinforcement/stiffening, etc. Examples include members in which materials are partially laminated for the purpose (for example, B-pillar reinforcement, outer panel), panel members (doors, hoods, etc.) having a hemmed portion, and the like.

(Regarding the manufacturing method of the adhesive bonding structure)
Next, a method for manufacturing the adhesive bonding structure 1 according to this embodiment will be briefly described.

The manufacturing method of the adhesive joint structure 1 according to the present embodiment includes a member forming step of forming each of the first member 2 and the second member 3 that constitute the adhesive joint structure 1, and and an adhesive bonding step of bonding the member 2 and the second member 3 using a predetermined adhesive.

<Member forming process>
The member forming step includes a base material manufacturing step of manufacturing base materials of the first member 2 and the second member using articles that are materials of the first member 2 and the second member 3, and if necessary After applying the film coating liquid for forming the film portion 22 to at least a part of the metal portion 21 of the base material that will be the first member 2, drying or baking is performed, A coating portion forming step of forming the coating portion 22, and a molding step of molding and processing the base material of the first member 2 and the base material of the second member 3 into a desired shape as necessary, including.

≪Base material manufacturing process≫
In the base material manufacturing process, base materials for the first member 2 and the second member are manufactured using articles that are materials for the first member 2 and the second member 3 . The method of manufacturing the base material is not particularly limited, and the base material may be manufactured according to a conventional method using various known manufacturing methods used to form the desired base material.

For example, when zinc-based plated steel sheets are used as the first member 2 and the second member 3, a hot-rolled steel sheet or cold-rolled steel sheet is produced by a conventional method, and the obtained hot-rolled steel sheet or cold-rolled steel sheet is On the other hand, a zinc-based plating layer may be formed by a conventional method. In addition, even when other metal materials, resin materials, FRP materials, ceramic materials, etc. are used as the base material, other metal materials, resin materials, FRP materials, ceramics, etc. All that is necessary is to manufacture the materials.

In addition, when performing the latter coating portion forming step, after the base material manufacturing step is completed, prior to performing the latter coating portion forming step, the metal member that will be the first member 2 is prepared. You may carry out the various painting surface treatment of. Various known treatment methods can be appropriately used as a method for such a coating base treatment. Examples of such treatment methods include an immersion drying method, an immersion/washing/drying method, a spray/washing/drying method, a coating/drying method, and a coating/drying/curing method. Also, the coating method is not particularly limited, and various known coating methods such as immersion, brush coating, spray, roll coater, bar coater and blade coater can be used.

≪Film formation process≫
The coating portion forming step is a step that is performed as necessary. In the coating portion forming step, the coating liquid for forming the coating portion 22 is applied to at least a part of the metal portion 21 of the base material that becomes the first member 2, and then dried or baked. The coating part 22 is formed by being performed.

Here, the method for producing the film coating solution is not particularly limited. For example, a solvent such as water is used according to the organic resin to be used. An organic resin containing one or more of them and a compound containing Si element may be blended at a desired solid content ratio, and mixed and stirred by various known methods.

The method of applying the film coating liquid for forming the film portion 22 is not particularly limited, and various known methods can be appropriately used. For example, when the film coating liquid is a viscous liquid, the film coating liquid is applied using a known method such as coating by a discharge method from a slit nozzle or a circular nozzle, brush coating, plate coating, and spatula coating. can do. Further, when using a film coating solution in which the above components are dissolved in a predetermined solvent, for example, brush coating, spray coating, bar coater, discharge coating from nozzles of various shapes, die coater coating, curtain coater coating, roll coating, Various known coating methods such as coater coating and inkjet coating can be used. In addition, various known methods such as bar coater, roll coater, screen printing, and powder coating can be employed.

Drying and baking can be performed by, for example, heat treatment. The heating conditions are not particularly limited. For example, a temperature condition of 80° C. or more and 250° C. or less and a drying/baking time of 5 seconds or more and 30 minutes or less can be used.

≪Molding process≫
In the forming process, the base material of the first member 2 and the base material of the second member 3 are formed into a desired shape as necessary. Here, the molding method is not particularly limited, and the processing means for obtaining the desired shape of the molded article may be selected from known metalworking methods. Also, if necessary, part of the molding process and the adhesive bonding process, which will be described later, may be performed at the same time.

<Adhesive bonding process>
The adhesive bonding step is a step of bonding the formed first member 2 and second member 3 using an adhesive made of phenoxy resin. In this step, first, an adhesive made of a phenoxy resin is placed on the portions to be adhered (for example, flange portions) of the obtained first member 2 and second member 3 to form a bonding region. 5 is formed. After that, after laminating the first member 2 and the second member 3 with the adhesion area 5 interposed therebetween, the adhesive composed of the phenoxy resin is cured by heat treatment. Here, the method of disposing the adhesive composed of the phenoxy resin is not particularly limited. You can do it. As a result, the adhesively bonded structure 1 according to the present embodiment, in which the first member 2 and the second member 3 are adhesively bonded via the adhesive layer 4, can be obtained.

In addition, in the adhesive bonding step, various coating treatments and other bonding treatments may be performed as necessary. For example, the joining process may be mechanical joining such as bolting or riveting, or welding such as spot welding.

More specifically, for example, when manufacturing the adhesively bonded structure 1D shown in FIG. 7, an adhesive is applied to one or both sides of the flange portion that joins the formed first member 2 and second member 3. It can be obtained by coating, laminating the joining portion of the first member 2 and the second member 3 via an adhesive, and curing the adhesive by maintaining at room temperature or heat treatment.

Further, for example, when the first member 2 as a metal member is reinforced with a second member 3 as a fiber-reinforced plastic as in the adhesive bonding structure 1 shown in FIG. The adhesive bonding structure 1 can be obtained by performing warm molding in a state in which the member 3 is laminated via an adhesive.

The method for manufacturing the adhesive bonding structure 1 according to this embodiment has been briefly described above. In addition, the adhesive bonding structure according to the present invention is not limited to one manufactured by the manufacturing method described above, and can be manufactured by any manufacturing method.

For example, the coating portion forming step may be performed after the forming process. Specifically, the base materials of the first member 2 and the second member 3 are formed into desired shapes. Next, a film portion is formed only on a portion to be adhesively bonded (a portion corresponding to the bonding region 5) of the base material after molding. After that, an adhesive is placed on the part, the first member 2 and the second member 3 are laminated via the adhesive, and the adhesive is cured to form the first member 2 and the second member. It is also possible to obtain an adhesively bonded structure 1 in which the member 3 is bonded via the adhesive layer 4 .

EXAMPLES The present invention will be described in more detail below with reference to examples. It should be noted that the embodiments described below are merely examples of the present invention, and are not intended to limit the present invention.

(Manufacturing of Adhesive Bonded Structure)
<Metal part>
Ten kinds of metal members shown below were prepared as the metal portion of the adhesive bonding structure.
(a) Galvannealed steel sheet (GA270) with a thickness of 1.0 mm and a tensile strength of 270 MPa
(b) Alloyed hot-dip galvanized steel sheet (GA590) having a tensile strength of 590 MPa at a thickness of 1.0 mm
(c) Alloyed hot-dip galvanized steel sheet (GA980) having a tensile strength of 980 MPa at a thickness of 1.0 mm
(d) Galvannealed steel sheet (GA1300) having a tensile strength of 1300 MPa at a thickness of 1.0 mm
(e) Cold-rolled steel sheet (CR270) with a thickness of 1.0 mm and a tensile strength of 270 MPa
(f) Cold-rolled steel sheet (CR590) with a thickness of 1.0 mm and a tensile strength of 590 MPa
(g) Cold-rolled steel sheet (CR980) having a tensile strength of 980 MPa at a thickness of 1.0 mm
(h) Cold-rolled steel sheet (CR1300) having a tensile strength of 1300 MPa at a thickness of 1.0 mm
(i) Hot-dip galvanized steel sheet (GI980) having a tensile strength of 980 MPa at a thickness of 1.0 mm
(j) Aluminum plate (Al) of standard A5052 with a thickness of 1.0 mm and a tensile strength of 290 MPa

Here, the method for producing the steel sheet and plated steel sheet of the above (a) to (i) will be described below.

A steel having the chemical composition shown in Table 1 below was subjected to hot rolling, pickling, and cold rolling according to a conventional method to obtain a cold-rolled steel sheet having a thickness of 1.0 mm. Next, for the metal members (e), (f), (g), and (h), the produced cold-rolled steel sheets were heated in a heating furnace until reaching the maximum temperature of 820°C at 3.5°C. The temperature was raised at an average heating rate of °C/sec, and then the samples were annealed by soaking in a soaking furnace at 820°C for a certain period of time to obtain samples. The atmosphere in the heating furnace and the soaking furnace was a nitrogen gas atmosphere containing 3% hydrogen.

For the metal member (i), the produced cold-rolled steel sheet is heated in a heating furnace at an average heating rate of 3.5 ° C./sec to reach the maximum temperature of 820 ° C., and then It was annealed by soaking in a soaking furnace at 820°C for a certain period of time, and cooled to 450°C. After that, it is immersed in a hot-dip plating bath containing hot-dip plating with a component of Zn-0.2% Al, and while pulling out the steel sheet from the plating bath, gas wiping is performed by blowing nitrogen gas from a slit nozzle to adjust the adhesion amount. did. The coating amount was adjusted to 60 g/m ² on one side. The atmosphere in the heating furnace and the soaking furnace was a nitrogen gas atmosphere containing 3% hydrogen.

For the metal members (a), (b), (c), and (d), the produced cold-rolled steel sheets were heated at 3.5°C/sec in a heating furnace until reaching the maximum temperature of 820°C. After that, it was annealed by soaking in a soaking furnace at 820°C for a certain period of time, and cooled to 450°C. After that, it is immersed in a hot-dip plating bath containing hot-dip plating with a component of Zn-0.1% Al, and while pulling out the steel sheet from the plating bath, nitrogen gas is blown from a slit nozzle to adjust the adhesion amount. did. Furthermore, by heating to 480° C. in an alloying furnace, the plating layer was alloyed and Fe was diffused in the plating. The adhesion amount was adjusted to 45 g/m ² on one side. The atmosphere in the heating furnace and the soaking furnace was a nitrogen gas atmosphere containing 3% hydrogen.

A commercially available A5052 aluminum plate was used as the metal member (j).

<Film coating solution>
The following 8 types of film coating liquids were prepared for forming the film portion.
(a) A water-dispersed emulsion type polyurethane resin SF-150 manufactured by DAIICHI KOGYO CO., LTD. and
(b) A water dispersion type emulsion type polyurethane resin SF-150 manufactured by DAIICHI KOGYO CO., LTD. and
(c) A water dispersion type emulsion type polyurethane resin SF-150 manufactured by DAIICHI KOGYO CO., LTD. and
(d) A coating solution B was prepared by blending a water-dispersible emulsion type epoxy resin EM-0461N manufactured by ADEKA and 3-glycidoxypropyltriethoxysilane at a solid content ratio of 3:2. .
(e) A water-dispersed emulsion type polyurethane resin MD-1100 manufactured by Toyobo Co., Ltd. and 3-glycidoxypropyltriethoxysilane were blended at a solid content ratio of 3:2 to prepare a film coating solution C. .
(f) A coating solution D was prepared by blending a water-dispersed emulsion type polyurethane resin SF-150 manufactured by DAIICHI KOGYO CO., LTD. and colloidal silica at a solid content ratio of 3:2.
(g) A film coating liquid E was prepared, which was an aqueous solution of only a water-dispersed emulsion type polyurethane resin SF-150 manufactured by DAIICHI KOGYO CO., LTD.
(h) A film coating solution F was prepared as an aqueous solution containing only 3-glycidoxypropyltriethoxysilane.

<Production of the first member>
The prepared film coating solution is applied on the above metal member with a bar coater under the conditions of each average thickness shown in Table 2 below, and dried at the maximum plate temperature (PMT 150 ° C.) in an induction heating furnace. By baking, a first member having a film portion formed thereon was produced. The average thickness of the coating was obtained by observing the cross section of the first member using a TEM or SEM, measuring the thickness of the coating at arbitrary five points, and calculating the average value. In addition, the state of the coating film was held for 5 seconds from the time of application until the start of drying. The coating film retention time was adjusted by controlling the conveying speed of the steel sheet from coating to the heating furnace. Drying of the coating film was performed at a maximum plate temperature (PMT) of 150° C. using an induction heating furnace. In addition, in Comparative Example 1 and Example 1, the coating portion was not formed.

<Preparation of Adhesive Bonded Structure>
≪Flange material≫
A metallic hat-shaped member having a flange was produced by molding the prepared first member. Next, the phenoxy resin Phenotote YP-50S (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) pellets manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. are spread over the flange portion of the formed molded body, and 5% by mass of glass beads are added. , attached another first member. After that, the material was heated and pressurized at a temperature of 200° C. and a pressure of 5 MPa for 5 minutes to be hot-melted to form a closed cross-section structure.

As a comparative example, 5% by mass of 200 μm glass beads were added to the surface of a galvannealed steel sheet (GA270) having a tensile strength of 270 MPa and an epoxy resin adhesive Penguin Cement #1066 manufactured by Sunstar Co., Ltd. The additive is applied, another galvannealed steel sheet (GA270) is pasted thereon, and the adhesive is cured by standing in an atmosphere of 170 ° C. for 30 minutes to form a closed cross-section structure. Created.

Moreover, in Example 22, a structure of a joining member was also produced by also spot-welding the flange portion to which the adhesive was applied. Specifically, using a CF-type Cr—Cu electrode with a tip diameter of 5 mm and R40, under welding conditions where the nugget diameter is 3 × t ^0.5 (t is the plate thickness [mm]), the spot spacing is 30 mm pitch. and spot welded. In addition, the adhesive layer was previously removed from the spot-welded portion before the spot-welding.

(Evaluation test method)
<Cross-sectional analysis of film>
IR analysis, TEM observation, and TOF-SIMS analysis were performed on the vertical cross section near the interface between the metal part and the adhesive layer in the obtained adhesively bonded structure according to the methods described above.

The film portion of the vertical cross section near the interface between the metal portion and the adhesive layer in the obtained adhesive bonding structure was inclined at 5 degrees with an oblique cutting device (SAICAS, DN-20S manufactured by Daipla Wintes Co., Ltd.). The film portion was enlarged by applying and cutting. As a microscopic IR (infrared spectroscopy) analysis in the film part, mapping measurement was performed using IRT-5200 manufactured by JASCO Corporation, and from the assignment of the observation peak derived from the resin component in the infrared absorption spectrum of the obtained film, the water-based polyurethane resin , epoxy resin, and polyester resin. Specifically, in the obtained infrared absorption spectrum, when a peak attributed to a C—N group near 1550 cm ⁻¹ and a peak attributed to a C═O group near 1740 cm ⁻¹ are observed. , determined to contain an aqueous polyurethane resin, and when a peak attributed to an epoxy group near 830 cm ^-1 is observed, it is determined to contain an epoxy resin, and C=O groups near 1720 to 1740 cm ^-1 If the assigned peak was observed, it was determined to contain a polyester resin.

A vertical section near the interface between the metal part and the adhesive layer was stained with Os, and then cut out by cryo- and room-temperature FIB-microsampling methods to prepare a thin film sample for TEM observation. Then, observed using FE-TEM (NB5000 manufactured by Hitachi High-Technologies Corporation), EDS under the conditions of a probe diameter of about 2 nm and an acceleration voltage of 200 kV for any three points near the interface between the metal part and the adhesive layer. Analysis (elemental mapping) was performed to obtain elemental maps of C, O and Si. C and other elements in the film portion of the obtained element map were binarized to calculate the presence or absence of Si element in the film portion, and the average particle size and area ratio of the resin particles. These results were evaluated as follows.

The film portion has a structure in which resin particles containing one or more of water-based polyurethane resin, epoxy resin, and polyester resin are dispersed in a compound phase containing Si element, and the average particle size of the resin particles is 20 nm or more. It was evaluated as A when it was less than 200 nm and the resin particles accounted for 20% or more and less than 80% of the cross-sectional area of the film, and it was evaluated as B when it did not have the above structure.

<TOF-SIMS analysis of adhesion interface>
The adhesive joint is cut from the adhesive layer side to the metal part side with an oblique cutting device (SAICAS, DN-20S type manufactured by Daipla Wintes Co., Ltd.) with an inclination of 5 degrees, and Ar sputtering is also used. Therefore, a sample having an adhesive layer with a thickness of about 1 μm was produced. An arbitrary point in the portion where the thickness of the adhesive layer was reduced to about 1 μm was analyzed by TOF-SIMS while argon sputtering was performed from the adhesive layer side toward the metal portion side. The analytical instrument used is TOF-SIMS TRIFT-V manufactured by ULVAC-PHI. After sputtering with an Ar beam from the surface to a certain depth, TOF-SIMS measurement was performed, and then similarly, the TOF-SIMS measurement was performed after sputtering was repeated, and the depth direction distribution was obtained for various elements and bonds. The primary ion species is Au ₃ ⁺ , the acceleration voltage is 30 kV, the sputtering speed is about 80 nm/min (in terms of SiO ₂ ), and the measurement area is 50 μm×50 μm. At the interface between the film (adhesive layer if it does not have a film) and the metal part, there is a peak indicating a Si—O—Me bond, and the peak count value is 15 or more. A case was evaluated as A, and B was evaluated as a case where there was no peak indicating the count value as described above.

In this embodiment, since cold-rolled steel sheets, two types of zinc-based plated steel sheets, and an aluminum plate are used as the metal members, the Si—O—Me bonds are Si—O—Fe bonds and Si— Three bonds, an O--Zn bond and a Si--O--Al bond, can be generated. Here, representative peak positions in TOF-SIMS corresponding to the above three bonds are as mentioned above.

Also, when a zinc-based plated steel sheet (GA/GI) is used, two bonds, Si--O--Fe bond and Si--O--Zn bond, can be generated. In this case, when the count value of at least one of the peaks corresponding to the Si--O--Fe bonds and the peaks corresponding to the Si--O--Zn bonds was 15 or more, it was evaluated as A.

<Bonding durability evaluation>
Bonding durability was evaluated for the obtained adhesively bonded structure according to each example.
First, the torsional stiffness of the adhesively bonded structure according to each example was measured and calculated using a torsion tester. Specifically, both ends of the adhesively bonded structure according to each example are fixed with jigs, and only one end is rotated about the central axis of the adhesively bonded structure, thereby torsionally deforming the adhesively bonded structure. was added. The torsion angle and torsion moment at this time were measured, and the torsion rigidity of each adhesive joint structure was calculated from the relationship between the torsion angle and torsion moment in the elastic deformation range. Specifically, the initial slope of the torsion angle-torsion moment diagram was used as the relationship between the torsion angle and the torsion moment in the elastic deformation range.

Next, the adhesive bonding structure according to each example was allowed to stand for 1000 hours in a constant temperature/humidity bath with a wet environment of 50° C. and a relative humidity of 95% to check the deterioration of the adhesive layer and the adhesive layer/film portion interface. promoted. The torsional stiffness of the adhesively bonded structure according to each example after standing in a constant temperature and humidity chamber was measured and calculated using a torsion tester. Then, the rate of decrease in torsional rigidity due to deterioration was calculated by comparing with the torsional rigidity of the adhesive joint body according to each example in which no deterioration test was performed. If the obtained decrease rate is less than 10%, it is evaluated as A, if it is 10% or more and less than 20%, it is evaluated as B, if it is 20% or more and less than 30%, it is evaluated as C, and if it is 40% or more. It was evaluated as D.

In addition, we observed the fracture surface after the bonding member fractured, and defined the fracture inside the adhesive layer as "cohesive failure of the adhesive", and fractured at the interface between the metal plate and the adhesive layer. Destruction at the interface between the plating layer of the plated steel sheet and the base material was defined as "plating failure", and the area ratio of each was measured. When each fracture area ratio is 0%, it is evaluated as A, when it is 0% or more and less than 10%, it is evaluated as B, when it is 10% or more and less than 50%, it is evaluated as C, and when it is 50% or more, it is D. evaluated.

The results obtained are summarized in Table 2 below.

As shown in Table 2, in the adhesively bonded structures of Examples 1 to 22, as compared with the adhesively bonded structure of Comparative Example 1, the decrease in torsional rigidity is greatly suppressed, and the adhesive durability is improved. was excellent in character.

On the other hand, in the adhesive bonding structure of Comparative Example 1, since the epoxy resin is inferior to the phenoxy resin in adhesiveness to the metal part, it is not possible to suppress the intrusion of water, and the effect of improving the adhesion durability cannot be obtained. rice field.

Comparing Examples 1 to 5, the effect of improving adhesion durability can be obtained by further providing the coating portion, and when the average thickness of the coating portion is within the range of 0.2 μm or more and 1.5 μm or less. In addition, it was possible to obtain the most effective effect of improving adhesion durability. On the other hand, it was found that when the average thickness of the film portion is too thick or too thin, it is difficult to obtain the effect of adhesion durability. Furthermore, if the average thickness is too thick, there is a possibility that spot welding cannot be used together.

Comparing Example 3 and Examples 6 to 12, the structure of the film portion is such that resin particles containing one or more of water-based polyurethane resin, epoxy resin, and polyester resin are dispersed in a phase composed of Si element. The adhesion durability is better when the average particle size of the resin particles is 20 nm or more and less than 200 nm, and the resin particles occupy 20% or more and less than 80% of the cross-sectional area of the film. I was able to get an improvement. This is probably because, in the case of having such a structure, both the adhesion between the metal portion and the film portion and the adhesion between the film portion and the adhesive layer can be achieved.

Comparing Example 3 and Example 10, the adhesive bonding structure of Example 3 using an organic silane compound has better adhesion durability than the adhesive bonding structure of Example 10 using an inorganic silane compound. It was possible to obtain a further effect of improving the properties. This is because the Si—O—Me bond in the adhesive bonding structure of Example 3 is a very strong bond, which suppresses the penetration of moisture between the metal part and the film part, and as a result, the metal This is probably because the adhesion between the part and the film part was improved.

In Examples 13 to 21, the adhesion durability was improved by forming the film portion regardless of the type of the metal portion. Comparing Example 3 and Examples 13 to 15, in the GA low-strength steel plate, stress concentration occurs due to deformation of the plate during the torsional rigidity test, so plating failure occurs between the plating of the GA steel plate and the base material. However, as the strength increases, it becomes clear that plating peeling is suppressed by suppressing deformation of the plate.

Comparing Example 3 and Example 22, when spot welding was used in combination, an effect of further improving adhesion durability was obtained.

Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention belongs can conceive of various modifications or modifications within the scope of the technical idea described in the claims. It is understood that these also naturally belong to the technical scope of the present invention.

1, 1A, 1B, 1C, 1D adhesive bonding structure 2, 2A, 2B, 2C, 2D first member 21, 21A metal portion 22, 22A coating portion 221 resin particles 223 compound phase 3, 3A, 3B, 3C, 3D second member 31 metal portion 32 film portion 321 resin particles 323 compound phase 4, 4A, 4B, 4C, 4D adhesive layer 5, 5B, 5C adhesion region

Claims (9)

A first member having a metal portion, a second member, and an adhesive layer that joins the first member and the second member, and an adhesive resin that constitutes the adhesive layer is a phenoxy resin ,
The first member further has a film portion disposed on at least a portion of the surface of the metal portion, the film portion containing an Si element derived from an organosilane compound having a glycidoxy group or a mercapto group, and an organic film containing at least one of a water-based polyurethane resin, an epoxy resin, and a polyester resin, wherein the film is formed into the adhesive layer so as to include an arbitrary part of the interface between the metal part and the film. When analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) while argon sputtering from the side toward the metal part side, the peak corresponding to the Si—O—Me bond (Me: metal element) is observed, and the count number indicating the Si—O—Me bond is 15 or more,
The analysis conditions of the TOF-SIMS are as follows: the primary ion species is Au ₃ ⁺ , the acceleration voltage is 30 kV, the sputtering speed is about 80 nm/min (in terms of SiO ₂ ), and the measurement area is 50 μm×50 μm. , adhesive bond structures. The film portion has a structure in which resin particles containing one or more of water-based polyurethane resin, epoxy resin, and polyester resin are dispersed in the film portion, and the average particle diameter of the resin particles is 20 nm or more. 2. The adhesive bonding structure according to claim 1 , wherein the resin particles have a diameter of less than 200 nm and occupy 20% or more and less than 80% of the cross-sectional area of the coating portion in a cross section along the thickness direction of the coating portion. 3. The adhesive bonding structure according to claim 1, wherein an average thickness of said coating portion is 0.2 [mu]m or more and 1.5 [mu]m or less per one side of said first member. The adhesive bonding structure according to any one of claims 1 to 3 , wherein the metal part is made of steel. The adhesive bonding structure according to any one of claims 1 to 4 , wherein the metal portion is a zinc-based plated steel sheet. The adhesive bonding structure according to any one of claims 1 to 5 , wherein the metal part is an alloyed hot-dip galvanized steel sheet having a tensile strength of 590 MPa or more. 7. The first member and the second member are bonded by bonding not depending on the adhesive layer in addition to bonding via the adhesive layer. The adhesive bond structure according to . 8. The adhesive bond structure according to claim 7 , wherein said second member has a metal portion, and said bonding not relying on an adhesive layer is spot welding. An automotive part comprising the adhesive joint structure according to any one of claims 1-8 .

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