Laminate for battery

Abstract

A laminate for a battery with a polypropylene adhesive layer and a metal substrate layer: (1) the adhesive includes 40-94 wt % of a propylene copolymer (A), 3-30 wt % of a butene-containing copolymer (B), 3-30 wt % of an ethylene-α-olefin copolymer (C) ((A), (B), and (C) is 100 wt %), (2) the copolymer (A) has a melting point of 130° C. or more measured with a differential scanning calorimeter, and a total proportion of a structural unit derived from ethylene is 4-25 mol % relative to 100 mol % of a total structural units forming all the copolymers (A) contained in the adhesive, (3) the copolymer (B) includes less than 1 mol % of a structural unit derived from ethylene, and has a melting point of 100° C. or less measured with a differential scanning calorimeter, and (4) the copolymer (C) includes 50-99 mol % of a structural unit derived from ethylene.

Claims

1. A laminate for a battery, comprising a polypropylene adhesive layer (I) and a metal substrate layer (II), wherein the polypropylene adhesive layer (I) satisfies at least requirements (1) to (4): (1) the adhesive comprises a propylene copolymer (A), a butene-containing copolymer (B), and an ethylene-propylene copolymer (C), and the adhesive comprises 40 to 94% by weight of the copolymer (A); 3 to 30% by weight of the copolymer (B); and 3 to 30% by weight of the copolymer (C) relative to 100% by weight of the total thereof; (2) the copolymer (A) is a polymer having a melting point of 130° C. or more measured with a differential scanning calorimeter, and a total proportion of a structural unit derived from ethylene is 4 to 25 mol % relative to 100 mol % of a total structural units forming all the copolymers (A) contained in the adhesive; (3) the copolymer (B) includes less than 1 mol % of a structural unit derived from ethylene, and has a melting point of 100° C. or less measured with a differential scanning calorimeter; and (4) the copolymer (C) includes 50 to 99 mol % of a structural unit derived from ethylene.

2. The laminate for a battery according to claim 1, wherein relative to 100 parts by weight of a total of the copolymers (A), (B), and (C), the polypropylene adhesive further comprises 0.1 to 15 parts by weight of a modified polyolefin (D) modified with at least one selected from unsaturated carboxylic acids and derivatives thereof.

3. The laminate for a battery according to claim 2, wherein the modified polyolefin (D) includes 0.01 to 5 parts by weight of a structural unit derived from the unsaturated carboxylic acid and a derivative thereof relative to 100 parts by weight of structural units excluding a structural unit derived from the unsaturated carboxylic acid and a derivative thereof, and a content of a structural unit derived from propylene in the structural units excluding the structural unit derived from the unsaturated carboxylic acid and a derivative thereof of the modified polyolefin (D) is 90 to 100 mol %.

4. The laminate for a battery according to claim 1, wherein the copolymer (A) comprises 10% by weight or more of a propylene-ethylene-α-olefin copolymer relative to 100% by weight of the copolymer (A) contained in the adhesive, and the α-olefin has 4 or more carbon atoms.

5. The laminate for a battery according to claim 4, wherein the propylene-ethylene-α-olefin copolymer is a propylene-ethylene-1-butene copolymer.

6. The laminate for a battery according to claim 1, wherein the copolymer (A) is a propylene-α-olefin copolymer, the α-olefin has 2 or 4 to 20 carbon atoms, and the copolymer (A) includes 1 to 55 mol % of a structural unit derived from the α-olefin, and has a melt flow rate of 0.1 to 50 g/10 min measured according to ASTM D 1238 at a temperature of 230° C. under a load of 2.16 kg.

7. The laminate for a battery according to claim 1, wherein the copolymer (B) includes 10 to 30 mol % of a structural unit derived from butene and 90 to 70 mol % of a structural unit derived from propylene, and has a melt flow rate of 0.1 to 50 g/10 min measured according to ASTM D 1238 at a temperature of 230° C. under a load of 2.16 kg.

8. The laminate for a battery according to claim 1, wherein the copolymer (C) has a melt flow rate of 0.1 to 70 g/10 min measured according to ASTM D 1238 at a temperature of 230° C. under a load of 2.16 kg.

9. The laminate for a battery according to claim 1, wherein the battery is a solar battery.

10. The laminate for a battery according to claim 1, wherein the battery is a lithium ion battery.

11. The laminate for a battery according to claim 1, wherein the battery is a fuel battery.

12. The laminate for a battery according to claim 1, wherein the metal substrate layer (II) contains at least one element selected from the group consisting of gold, copper, iron, chromium, zinc, cobalt, aluminum, titanium, tin, indium, magnesium, molybdenum, manganese, and silicon.

Description

EXAMPLES

(1) Hereinafter, the present invention will be more specifically described by way of Examples and Comparative Examples, but these Examples are not limitative to the present invention within the scope thereof.

(2) [MFR]

(3) The MFR was measured according to ASTM D 1238 at 230° C. under a load of 2.16 kg.

(4) [Density]

(5) The density was measured according to JIS K7112.

(6) [Melting Point (Tm)]

(7) The Tm of the copolymer used as raw materials for an adhesive listed below was measured by differential scanning calorimetry according to the following method.

(8) A sample (about 5 mg) was filled into a dedicated aluminum pan. Using DSC Pyris1 or DSC7 made by PerkinElmer Inc., the sample was heated from 30° C. to 200° C. at 320° C./min, and was kept at 200° C. for 5 minutes. The sample was then cooled from 200° C. to 30° C. at 10° C./min, and was kept at 30° C. for another 5 minutes, followed by heating at 10° C./min. From the endothermic curve in this heating at 10° C./min, the melting point was determined.

(9) If several peaks were detected during the measurement, the peak temperature detected at the highest temperature was defined as the melting point (Tm).

(10) [Polymer Composition]

(11) The contents of the structural unit derived from propylene, the structural unit derived from ethylene, and the structural unit derived from α-olefin in the copolymer used as a raw material for the adhesive below were measured by .sup.13C-NMR under the following condition using the following apparatus.

(12) The contents of the structural units derived from propylene, ethylene, and α-olefin were determined using a JECX 400P nuclear magnetic resonance apparatus made by JEOL, Ltd. under the following condition: A deuterated ortho-dichlorobenzene/hexadeuterobenzene (80/20 vol %) mixed solvent was used as a solvent, the sample concentration was 60 mg/0.6 mL, the temperature for measurement was 120° C., the observation nuclear was .sup.13C (100 MHz), the sequence was single-pulse proton decoupling, the pulse width was 4.62 microseconds (45° pulse), the repetition time was 5.5 seconds, the number of integrations was 8000 times, and a reference value of chemical shift was 29.73 ppm.

(13) [Ethylene Content Z]

(14) Based on the expression, using the amount of the copolymer (A) used in the adhesive and the content of the structural unit derived from ethylene in the copolymer (A) measured in [Polymer composition], the total proportion of the structural unit derived from ethylene (ethylene content Z) relative to 100 mol % of the total structural units forming the copolymer (A) contained in the adhesive was calculated.

(15) [Amount of Structural Unit Derived from Unsaturated Carboxylic Acid And Derivative Thereof]

(16) The amount (graft amount) of the structural units derived from the unsaturated carboxylic acid and a derivative thereof was determined as follows: The intensity of the peak (1790 cm.sup.−1 if maleic anhydride was used) derived from the structural unit was measured with an infrared absorption analyzer, and the amount of the structural units was determined using the calibration curve preliminarily created.

(17) [Weight Average Molecular Weight (Mw) and Molecular Weight Distribution (Mw/Mn)]

(18) The Mw and Mw/Mn of the copolymer used as the raw material for the following adhesive were measured using columns connected in series (two TSKgel GMH6-HT columns and two TSKgel GMH6-HTL columns all made by Tosoh Corporation and having a column size, i.e., a diameter of 7.5 mm and a length of 300 mm) with a liquid chromatography (made by TA Instruments-Waters LLC, Alliance/GPC2000). The medium of the mobile phase used was o-dichlorobenzene containing 0.025% by weight of an antioxidant (butylhydroxytoluene, made by Takeda Pharmaceutical Company Limited), and the measurement was performed under a condition at a sample concentration of 0.15% (V/W), a flow rate of 1.0 mL/min, and a temperature of 140° C. In the case where the copolymer has a molecular weight of 500 to 20,600,000, standard polystyrenes made by Tosoh Corporation were used here.

(19) The obtained chromatogram was analyzed by a known method using data processing software Empower 2 made by TA Instruments-Waters LLC to calculate the number average molecular weight (Mn), the Mw, and the Mw/Mn using the calibration curve created from the standard polystyrene samples.

(20) (Polyolefins Used)

(21) The polyolefins used in Examples and Comparative Examples are listed below. These polyolefins all were prepared through polymerization according to a normal method, unless otherwise specified.

(22) [Propylene Copolymer (A)]

(23) PP: random polypropylene (MFR=7.0 g/10 min, density=0.90 g/cm.sup.3, ethylene content=3 mol %, propylene content=96 mol %, butene content=1 mol %, melting point=140° C.) PBER: ethylene-propylene-α-olefin copolymer (MFR=7.0 g/10 min, density=0.87 g/cm.sup.3, ethylene content=13 mol %, propylene content=68 mol %, butene content=19 mol %, melting point=140° C., Mw/Mn=2.1)
[Butene-Containing Copolymer (B)] PBR-1: propylene-butene random copolymer (MFR=7.0 g/10 min, density=0.88 g/cm.sup.3, propylene content=74 mol %, butene content=26 mol %, melting point=75° C., Mw/Mn=2.1) PBR-2: propylene-butene random copolymer (MFR=7.0 g/10 min, density=0.89 g/cm.sup.3, propylene content=85 mol %, butene content=15 mol %, melting point=98° C., Mw/Mn=2.2)
[Ethylene-α-Olefin Copolymer (C)] EPR: ethylene-α-olefin copolymer (MFR=8.0 g/10 min, density=0.87 g/cm.sup.3, ethylene content=80 mol %, propylene content=20 mol %, Mw/Mn=2.1) EBR: ethylene-α-olefin copolymer (MFR=8.0 g/10 min, density=0.87 g/cm.sup.3, ethylene content=85 mol %, butene content=15 mol %, Mw/Mn=2.1)
[Modified Polyolefin (D)] Modified PP: modified isotactic homopolypropylene

(24) (MFR=100 g/10 min, density=0.90 g/cm.sup.3, graft amount of maleic anhydride=3.0 wt %)

Example 1

(25) <Preparation of Propylene Adhesive>

(26) PP (45% by weight), PBER (20% by weight), PBR-1 (10% by weight), EPR (20% by weight), and modified PP (5% by weight) were melt kneaded using a single screw extruder at 230° C. to yield a propylene adhesive. The resulting propylene adhesive had an MFR of 8.2 g/10 min and a density of 0.89 g/cm.sup.3.

(27) <Preparation of Laminate for Battery and Adhesive Force>

(28) Using an extrusion molding machine provided with a T die, the adhesive prepared in Example 1 was molded into a film having a thickness of 50 μm. The resulting film was sandwiched between two aluminum foils having a thickness of 300 μm, and was heat sealed with a heat sealer at 160° C. and 0.1 MPa for 5 seconds. The resulting multi-layer film was cut into a width of 20 mm, and the adhesive force (unit: N/20 mm) between the aluminum foils and the adhesive layer was measured using a tensile tester by 180° peel method at room temperature (23° C.) or 110° C. The crosshead speed was 200 mm/min. The result is shown in Table 1.

Examples 2 to 4, Comparative Examples 1 to 3

(29) Adhesives were prepared by the same method as in Example 1 except that propylene adhesives were prepared according to the compounding formula shown in Table 1. Laminates were prepared using the resulting adhesives, and the adhesive forces were measured. The results are shown in Table 1.

(30) TABLE-US-00001 TABLE 1 Example Example Example Example Comparative Comparative Comparative 1 2 3 4 Example 1 Example 2 Example 3 PP wt % 45 45 35 45 75 65 55 PBER wt % 20 20 20 20 20 PBR-1 wt % 10 20 10 10 PBR-2 wt % 10 EPR wt % 20 20 20 20 20 20 EBR wt % 20 Modified PP wt % 5 5 5 5 5 5 5 Ethylene mol % 6.1 6.1 6.6 6.1 3.0 3.0 5.7 content Z MFR g/10 8.2 8.2 8.2 8.2 8.2 8.2 8.2 min Density g/cm.sup.3 0.89 0.89 0.88 0.89 0.89 0.89 0.89 Adhesive N/20 120 130 140 170 80 90 100 force mm (23° C.) Adhesive N/20 120 110 100 120 30 40 40 force mm (110° C.)