LAMINATED BODY

Abstract

The invention provides a laminated body having an excellent adhesive force with respect to a low-polarity metal member in the presence of hot water. The laminated body contains a resin substrate; an easily adhesive layer provided on at least one surface of the resin substrate; and an adhesive resin layer provided on a surface of the easily adhesive layer on a side opposite to the resin substrate, wherein the adhesive resin layer contains a polyolefin having at least one group selected from the group consisting of an acidic group and an acid anhydride group and having an acid value of 0.01 mgKOH/g to 6.5 mgKOH/g; and the laminated body is used for bonding a metal member having a ratio of a dipole term in surface free energy of 0.01% to 5.0%.

Claims

1. A laminated body comprising: a resin substrate; an easily adhesive layer provided on at least one surface of the resin substrate; and an adhesive resin layer provided on a surface of the easily adhesive layer on a side opposite to the resin substrate, wherein the adhesive resin layer contains a polyolefin having at least one group selected from the group consisting of an acidic group and an acid anhydride group and having an acid value of 0.01 mgKOH/g to 6.5 mgKOH/g; and the laminated body is used for bonding a metal member having a ratio of a dipole term in surface free energy of 0.01% to 5.0%.

2. The laminated body according to claim 1, wherein a solubility parameter of the easily adhesive layer is larger than a solubility parameter of the adhesive resin layer and smaller than a solubility parameter of the resin substrate, and an absolute value of a difference between the solubility parameter of the easily adhesive layer and the solubility parameter of the adhesive resin layer is 3.0 (J/cm.sup.3).sup.1/2 or less.

3. The laminated body according to claim 1, wherein the easily adhesive layer has a thickness of 8 nm to 200 nm.

4. The laminated body according to claim 1, wherein the resin substrate has a glass transition temperature of 90° C. or higher.

5. The laminated body according to claim 1, wherein the laminated body includes the easily adhesive layer provided on each of both surfaces of the resin substrate, and the adhesive resin layer provided on each of surfaces of the easily adhesive layer on a side opposite to the resin substrate.

6. The laminated body according to claim 1, wherein the acidic group contains a carboxylic acid group.

7. The laminated body according to claim 1, wherein the acid anhydride group contains a carboxylic acid anhydride group.

8. The laminated body according to claim 1, wherein the polyolefin contains a propylene unit, and a content of the propylene unit is 50% by mass or more with respect to the polyolefin.

9. The laminated body according to claim 1, wherein the polyolefin has an acid value of 0.01 mgKOH/g to 3.0 mgKOH/g.

10. The laminated body according to claim 1, wherein the adhesive resin layer further contains a styrene-based thermoplastic elastomer.

11. The laminated body according to claim 10, wherein a content of the styrene-based thermoplastic elastomer is 20% by mass or less with respect to a total amount of the polyolefin and the styrene-based thermoplastic elastomer.

12. The laminated body according to claim 1, wherein the adhesive resin layer has an acid value of 0.01 mgKOH/g to 6.5 mgKOH/g.

13. A method for bonding a metal member using a laminated body, wherein the laminated body is the laminated body according to claim 1, and the metal member has a ratio of a dipole term in surface free energy of 0.01% to 5.0%.

Description

EXAMPLES

[0199] Hereinafter, the present disclosure will be described in detail with reference to Examples, but the present disclosure is not limited thereto. Unless otherwise specified, “parts” and “%” are based on mass.

1. Measuring Method [Acid Value]

[0200] An acid value indicates the number of milligrams of potassium hydroxide required to neutralize an acid contained in 1 g of a sample.

[0201] The acid value was measured in accordance with JIS K 0070: 1992.

[0202] Specifically, a precisely weighed sample is dissolved in a mixed solvent having a mass ratio of mixed xylene: n-butanol=1:1 to obtain a sample solution. Next, to this sample solution, a few drops of 1 w/v % phenolphthalein solution in ethanol are added as an indicator. Using a 0.1 mol/L potassium hydroxide solution in ethyl alcohol as a titrant, titration is carried out. The acid value is calculated according to the following formula.

Acid value=(T×F×56.11×0.1)/W

[0203] Here, in the above calculation formula, T represents a titration amount (mL); F represents a factor of a titrant; and W represents a sampled amount (g).

[MFR]

[0204] MFR (unit: g/10 min) was measured under the following conditions. [0205] Device: Flow tester CFT-500 (manufactured by Shimadzu Corporation) [0206] Dice: Φ1 mm×10 mm [0207] Test pressure: 1.96 MPa [0208] Cylinder area: 1 cm.sup.2 [0209] Cylinder temperature: 230° C.

[Surface Free Energy]

[0210] A contact angle was measured by a three-point method under the following conditions according to the sessile drop method using a contact angle meter defined in JIS R 3257: 1999, and γ.sub.M, γ.sub.M.sup.D, γ.sub.M.sup.P, γ.sub.M.sup.H, γ.sub.A, γ.sub.A.sup.D, γ.sub.A.sup.P, and γ.sub.A.sup.H were calculated using the extended Fowkes formula. The γ.sub.L, γ.sub.L.sup.D, γ.sub.L.sup.P, and γ.sub.L.sup.H of each liquid used in the sessile drop method are shown in Table 1 below.

[0211] Device: CA-X type contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.)

[0212] Measurement temperature: 25° C.

[0213] Liquid: water, α-bromonaphthalene, diiodomethane

TABLE-US-00001 TABLE 1 Liquid γ.sub.L γ.sub.L.sup.D γ.sub.L.sup.P γ.sub.L.sup.H Water 72.8 29.1 1.3 42.4 α-bromonaphthalene 44.6 44.4 0.2  0.0 Diiodomethane 50.8 46.8 4.0  0.0

[Glass Transition Temperature]

[0214] 10 mg of a sample was sealed within an aluminum measuring pan. The pan was mounted in a differential scanning calorimeter (DSC Model Q100 manufactured by TA Instruments). The temperature was increased from 25° C. to 300° C. at a rate of 20° C./min, and was held at 300° C. for 5 min. Then, the pan was removed therefrom and quenched by cooling on a metal plate. The pan was again mounted in the differential scanning calorimeter, and the temperature was increased from 25° C. at a rate of 20° C./min to measure a glass transition temperature (Tg: ° C.) and a melting point (Tm: ° C.). The glass transition temperature was taken as an extrapolated start temperature.

[Thickness]

[0215] The thickness of each layer was measured according to the provision of JIS K 7130: 1999.

[Solubility Parameter (SP Value)]

[0216] The SP value was obtained by the following method.

[0217] The SP value was obtained by calculation from the chemical structural formulae of a resin substrate, adhesive resin layer, and easily adhesive layer used by referring to “Polymer Eng. & Sci.”, Vol. 14, No. 2 (1974), pages 148 to 154 using the Fedors calculating formula.

δi=[Ev/V].sup.1/2=[Δei/Δvi]/.sup.1/2

[0218] Ev: Evaporation energy

[0219] V: Molar volume

[0220] Δei: evaporation energy of atom or atom group of component

[0221] Δvi: molar volume of atom or atom group of component i

[0222] The SP value was obtained from the following formula as the sum of all atoms or all atom groups.

σ=(Σei/Σvi).sup.1/2

2. Physical Properties of Resin Used

[0223] The acid values and MFRs of the resins used are shown in the following Table 2.

TABLE-US-00002 TABLE 2 Acid value MFR Structure 1) 2) Com- A1 Polypropylene having acidic group 0.76 3.2 po- and acid anhydride group nent (propylene unit: 94.93% by mass, olefin unit (A) other than propylene: 5.00% by mass, maleic anhydride unit (containing partially hydrolyzed one): 0.07% by mass) A2 Polypropylene having acidic group 0.80 9.1 and acid anhydride group (propylene unit: 99.92% by mass, maleic anhydride unit (containing partially hydrolyzed one): 0.08% by mass) Com- B1 Styrene-ethylene/propylene-s 0.0 70 po- tyrene type block copolymer having nent no acidic group and no acid anhydride group (B) (styrene unit: 30% by mass) B2 Styrene-ethylene/butylene-styrene 10.0 8.0 type block copolymer having acidic group and acid anhydride group (styrene unit: 20% by mass, maleic anhydride unit (containing partially hydrolyzed one): 1.03% by mass) B3 Styrene-ethylene/butylene-styrene 0.0 4.0 type block copolymer having amino group (styrene unit: 30% by mass) PA Nylon-based copolymerized polyamide resin 7.0 6.0 PES Saturated copolymerized polyester resin 0.8 60 PP Polypropylene having acidic group 10.3 22 and acid anhydride group (propylene unit: 80.85% by mass, olefin unit other than propylene: 14.55% by mass, maleic anhydride unit (containing partially hydrolyzed one): 4.6% by mass) 1) Acid value: mgKOH/g 2) MFR: g/10 min

3. Physical Properties of Metal Members Used

[0224] Table 3 below shows the material, surface free energy, a dispersion term, dipole term, and hydrogen bond term thereof, and the ratio of the dipole term to the surface free energy of each of five metal members (M1 to M5) used. As the metal member, a plate having a size of 10 mm×30 mm and a thickness of 100 μm was used.

TABLE-US-00003 TABLE 3 Metal member M1 M2 M3 M4 M5 Material Titanium Titanium Titanium Titanium Titanium Surface free energy γ.sub.M 47.1 49.7 50.9 45.0 51.6 Dispersion term γ.sub.M.sup.D 45.0 43.0 43.0 45.0 47.8 Dipole term γ.sub.M.sup.P 0.4 3.2 5.6 0.0 2.5 Hydrogen bond term γ.sub.M.sup.H 1.7 3.5 2.3 0.0 1.1 Ratio of dipole term: 0.85 6.4 11.0 0.0 4.8 γ.sub.M.sup.P/γ.sub.M × 100 (%)

4. Example 1 [Production of Laminated Body]

(Preparation of Easy Adhesive Agent)

[0225] An easy adhesive agent (solid content concentration: 4% by mass) was prepared according to the following formulation. As a diluent solvent, ion-exchanged water was used. [0226] Acrylic resin (trade name: RX7770 manufactured by Nippon Carbide Co., Ltd.): 85 parts by mass [0227] Epoxy-based crosslinking agent (trade name: TETRAD-X manufactured by Mitsubishi Gas Chemical Co., Ltd.): 7.5 parts by mass [0228] Surfactant (trade name: SANNONIC SS-70 manufactured by Sanyo Chemical Industries, Ltd.): 7.5 parts by mass

(Production of Resin Substrate Including Easily Adhesive Layer)

[0229] Polyethylene-2,6-naphthalate (shown as “PEN” in Table 4) having an intrinsic viscosity of 0.60 dl/g (35° C., orthochlorophenol) was synthesized using manganese acetate tetrahydrate as a transesterification catalyst and antimony trioxide as a polymerization catalyst. The obtained resin was dried with a dryer at 170° C. for 6 hours, then charged into an extruder, where the resin was melt-kneaded at a melting temperature of 300° C. The resin was extruded through a die slit at 300° C., and then cooled and solidified on a casting drum set at a surface temperature of 25° C. to prepare an unstretched film. The unstretched film was guided to a group of rolls heated to 140° C., stretched by a factor of 3.5 times in a machine direction, and cooled by a group of rolls at 25° C.

[0230] The easy adhesive agent was applied to each of both surfaces of the film after longitudinal stretching by a roll coater method so that the thickness of an easily adhesive layer in a laminated body to be finally obtained was 50 nm. Subsequently, the film was guided into a tenter while both ends of the film were held by clips, where the film was stretched by a factor of 3.5 times in a transverse direction in an atmosphere heated to 135° C. In the tenter, heat fixation was performed at 220° C. for 40 seconds. The film was relaxed by 1% in a transverse direction at 220° C., and then uniformly cooled slowly to room temperature to obtain a biaxially stretched film having a thickness of 200 μm.

(Formation of Adhesive Resin Layer)

[0231] Next, adhesive resin layers having compositions shown in Table 4 were formed on the easily adhesive layers on both surfaces of the obtained biaxially stretched film by an extrusion lamination method to obtain a laminated body. The thickness of each of the obtained adhesive resin layers was 50 μm. The extrusion lamination condition included an extrusion temperature of 230° C.

5. Examples 2 to 5 and 10, and Comparative Examples 1 to 8

[0232] A laminated body was produced in the same manner as in Example 1 except that the configuration of an adhesive resin layer, and a metal member to be used were changed as shown in Table 4.

6. Example 6

[0233] A laminated body was produced in the same manner as in Example 1 except that a resin substrate including an easily adhesive layer was produced according to the following.

[0234] Polyethylene terephthalate (shown as “PET” in Table 4) having an intrinsic viscosity of 0.58 dl/g (35° C., orthochlorophenol) was synthesized as a resin using manganese acetate tetrahydrate as a transesterification catalyst and antimony trioxide as a polymerization catalyst. The obtained resin was dried with a dryer at 170° C. for 6 hours, then charged into an extruder, where the resin was melt-kneaded at a melting temperature of 300° C.

[0235] The resin was extruded through a die slit at 300° C., and then cooled and solidified on a casting drum set at a surface temperature of 25° C. to prepare an unstretched film.

[0236] The unstretched film was guided to a group of rolls heated to 140° C., stretched by a factor of 3.5 times in a machine direction, and cooled by a group of rolls at 25° C.

[0237] Subsequently, an easy adhesive agent was applied to each of both surfaces of the film after longitudinal stretching by a roll coater method in the same manner as in Example 1.

[0238] Subsequently, the film was guided into a tenter while both ends of the film were held by clips, where the film was stretched by a factor of 3.5 times in a transverse direction in an atmosphere heated to 135° C. Then, in the tenter, heat fixation was performed at 220° C. for 40 seconds. The film was relaxed by 1% in the transverse direction at 220° C., and then uniformly cooled slowly to room temperature to obtain a biaxially stretched film having a thickness of 200 μm.

7. Examples 7 to 9

[0239] A laminated body was produced in the same manner as in Example 1 except that the configuration of an easily adhesive layer was changed as shown in Table 4.

8. Evaluation

[0240] Using the laminated bodies of Examples 1 to 10 and Comparative Examples 1 to 8, peeling adhesive strength and a dropping time in a constant load immersion test were evaluated. The evaluation results are collectively shown in Table 4.

[Peeling Adhesive Strength]

[0241] Each of the laminated bodies of Examples 1 to 10 and Comparative Examples 1 to 8 was cut into a size of 10 mm×20 mm. A plate-shaped metal member selected according to the description of Table 4 was thermocompression-bonded to the adhesive resin layer on each of both surfaces of each of the obtained laminated bodies to prepare an assembly. This condition included a temperature of 160° C., a pressure of 3.0 MPa, and a pressure bonding time of 10 seconds. In the preparation of the assembly, by aligning one end portion of the laminated body in the longitudinal direction with one end portion of the metal member in the machine direction, and thermocompression-bonding the metal member to the laminated body, a portion to which the adhesive resin layer was not bonded was provided on the other end portion of the metal member in the longitudinal direction in the assembly. Then, the assembly was housed in an environment adjusted to 25° C. for 3 days to obtain a test piece.

[0242] Among the two metal members of the obtained test piece, a portion to which the adhesive resin layer was not bonded was fixed to each of upper and lower chucks, and peeling adhesive strength (N/10 mm) between the metal member and the adhesive resin layer was measured. The measurement condition included a temperature of 25° C. and a tensile speed of 30 mm/min.

[Dropping Time in Constant Load Immersion Test (Hot Water Resistance)]

[0243] In one metal member of a test piece prepared in the same procedure as in the peeling adhesive strength, a portion to which the adhesive resin layer was not bonded was suspended from above using a hook, and a weight was attached to a portion to which the adhesive resin layer was not bonded in the other metal member using a hook. A load was applied to the test piece using the weight so as to set a load to 0.4 N/mm in hot water. The test piece was immersed in hot water at 95° C. together with the weight, and a time until the bonded site was peeled off and the weight dropped was measured.

TABLE-US-00004 TABLE 4 Example Example Example Example Example Example Example 1 2 3 4 5 6 7 Resin Resin PEN PEN PEN PEN PEN PET PEN substrate Glass transition 118 118 118 118 118 78 118 temperature (° C.) Easily adhesive Resin Acrylic Acrylic Acrylic Acrvlic Acrylic Acrylic Polyester layer Thickness (nm) 20 20 20 20 20 20 20 Adhesive resin Component A1 100 — — — — 100 100 layer (A) A2 — 100 95 95 95 — — Component B1 — — 5 — — — — (B) B2 — — — 5 — — — B3 — — — — 5 — — PA — — — — — — — PES — — — — — — — PP — — — — — — — Acid value 0.76 0.80 0.76 1.26 0.75 0.76 0.76 (mgKOH/g) MFR (g/10 min) 8.2 9.1 10 12 8.5 8.2 8.2 Surface free 30.6 26.7 40.7 22.1 35.4 30.6 30.6 energy γ.sub.A Dispersion term 27 26.2 30.3 20.8 30.1 27 27 γ.sub.A.sup.D Dipole term γ.sub.A  3.3 0.1 8.1 0.2 3.9 3.3 3.3 Hydrogen bond 0.3 0.4 2.3 1.1 1.4 0.3 0.3 term γ.sub.A  Metal member Kind of adherend M1 Surface free 47.1 energy γ.sub.M Dispersion term 45 γ.sub.M.sup.D Dipole term γ.sub.M  0.4 Hydrogen bond 1.7 term γ.sub.M  Ratio of dipole 0.85 0.85 0.85 0.85 0.85 0.85 0.85 term: γ.sub.M  /γ.sub.M × 100 (%) Characteristics Difference in 16.5 20.4 6.4 25 11.7 16.5 16.5 surface free energy between adherend and adhesive resin layer: γ.sub.M − γ.sub.A (mN/m) SP value 8.5 8.5 8.3 8.3 8.3 8.5 8.5 (achesive resin layer) SP value (easily 10.5 10.5 10.5 10.5 10.5 10.5 10.6 adhesive layer) SP value (resin 12.9 12.9 12.9 12.9 12.9 10.7 12.9 substrate) Evaluation Peeling adhesive 25.0 28.0 27.0 35.0 28.0 25.0 25.0 strength (N/10 mn) Dropping time in 401 490 660 560 622 398 405 constant load immersion test (hrs) Comparative Comparative Comparative Comparative Example Example Example Example Example Example Example 8 9 10 1 2 3 4 Resin Resin PEN PEN PEN PEN PEN PEN PEN substrate Glass transition 118 118 118 118 118 118 118 temperature (° C.) Easily adhesive Resin Acrylic Acrylic Acrylic Acrylic Acrylic Acrylic Acrylic layer Thickness (nm) 10 200 20 20 20 20 20 Adhesive resin Component A1 100 100 — — — — — layer (A) A2 — — 95 100 95 95 — Component B1 — — 5 — 5 5 — (B) B2 — — — — — — — B3 — — — — — — — PA — — — — — — 100 PES — — — — — — — PP — — — — — — — Acid value 0.76 0.76 0.76 0.80 0.76 0.76 7.0 (mgKOH/g) MFR (g/10 min) 8.2 8.2 10 9.1 10 10 6.0 Surface free 30.6 30.6 40.7 26.7 40.7 40.7 43 energy γ.sub.A Dispersion term 27 27 30.3 26.2 30.3 30.3 40.2 γ.sub.A.sup.D Dipole term γ.sub.A  3.3 3.3 8.1 0.1 8.1 8.1 1.9 Hydrogen bond 0.3 0.3 2.3 0.4 2.3 2.3 0.3 term γ.sub.A  Metal member Kind of adherend M1 M5 M2 M3 M1 Surface free 47.1 51.6 49.7 50.9 47.1 energy γ.sub.M Dispersion term 45 47.8 43 43 45 γ.sub.M.sup.D Dipole term γ.sub.M  0.4 2.5 3.2 5.6 0.4 Hydrogen bond 1.7 1.1 3.5 2.3 1.7 term γ.sub.M  Ratio of dipole 0.85 0.85 4.8 6.4 6.4 11 0.85 term: γ.sub.M  /γ.sub.M × 100 (%) Characteristics Difference in 16.5 16.5 10.9 23 9 10.2 4.1 surface free energy between adherend and adhesive resin layer: γ.sub.M − γ.sub.A (mN/m) SP value 8.5 8.5 8.3 8.5 8.3 8.5 13.6 (achesive resin layer) SP value (easily 10.6 16.6 10.5 10.5 10.5 10.5 10.5 adhesive layer) SP value (resin 12.9 12.9 12.9 12.9 12.9 12.9 12.9 substrate) Evaluation Peeling adhesive 25.0 25.0 27 28.0 26.0 26.0 40.0 strength (N/10 mn) Dropping time in 403 400 816 20 38 35 4 constant load immersion test (hrs) Comparative Comparative Comparative Comparative Example Example Example Example 5 6 7 8 Resin Resin PEN PEN PEN PEN substrate Glass transition 118 118 118 118 temperature (° C.) Easily adhesive Resin Acrylic Acrylic Acrylic Acrylic layer Thickness (nm) 20 20 20 20 Adhesive resin Component A1 — — 100 — layer (A) A2 — — — — Component B1 — — — — (B) B2 — — — — B3 — — — — PA — — — — PES 100 100 — — PP — — — 100 Acid value 0.8 0.8 0.76 10.3 (mgKOH/g) MFR (g/10 min) 60 60 8.2 22 Surface free 46.3 46.3 30.6 37.3 energy γ.sub.A Dispersion term 36.3 36.3 27 29.3 γ.sub.A.sup.D Dipole term γ.sub.A  8.7 8.7 3.3 4.4 Hydrogen bond 1.3 1.3 0.3 3.6 term γ.sub.A  Metal member Kind of adherend M2 M4 M4 M1 Surface free 49.7 45 45 47.1 energy γ.sub.M Dispersion term 43 45 45 45 γ.sub.M.sup.D Dipole term γ.sub.M  3.2 0 0 0.4 Hydrogen bond 3.5 0 0 1.7 term γ.sub.M  Ratio of dipole 6.4 0 0 0.85 term: γ.sub.M  /γ.sub.M × 100 (%) Characteristics Difference in 3.4 −1.3 14.4 9.8 surface free energy between adherend and adhesive resin layer: γ.sub.M − γ.sub.A (mN/m) SP value 10 10 8.5 11.0 (achesive resin layer) SP value (easily 10.5 10.5 10.5 10.5 adhesive layer) SP value (resin 12.9 12.9 12.9 12.9 substrate) Evaluation Peeling adhesive 28.0 28.0 25 40 strength (N/10 mn) Dropping time in 8 5 69 3 constant load immersion test (hrs) indicates data missing or illegible when filed

[0244] From Table 4, the laminated bodies of Examples 1 to 10 were found to have more excellent hot water resistance than that of the laminated bodies of Comparative Examples 1 to 8.

INDUSTRIAL APPLICABILITY

[0245] The laminated body of the present disclosure can be used in various fields such as an electric field, an automobile field, and other industrial fields, particularly in the field of an on-vehicle battery such as a fuel cell.