Swelling tape for filling gap

Abstract

The present application relates to a swelling tape and a method of filling a gap. The swelling tape is, for example, applied in gaps in which a fluid is present and deformed into a three-dimensional shape to fill the gaps and fix in place objects separated by gaps as needed.

Claims

1. A swelling tape for filling a gap, comprising: a substrate layer that is deformed in a length direction upon contact with a fluid; a pressure-sensitive adhesive layer formed in a direction parallel to the length direction of the substrate layer on one surface of the substrate layer, and satisfying Equation 1; and a back-side coating layer present on a surface opposite to the surface of the substrate layer on which the pressure-sensitive adhesive layer is formed, wherein the substrate layer has a shore A hardness according to ASTM D2240 of 70 A or more, or the substrate layer has a shore D hardness according to JIS K-7311 of 40 D or more, wherein the recited hardnesses are maintained after the substrate is in contact with the fluid, wherein the back-side coating layer comprises at least one selected from the group consisting of a fluorine-based releasing agent, a silicon-based releasing agent, a releasing agent containing silicon and having a vinyl or acrylic group, and an amide-based releasing agent:
1.5X.sub.2/X.sub.1150[Equation 1] where X.sub.1 is a peeling strength of the pressure-sensitive adhesive layer measured at room temperature, and at a peeling rate of 5 mm/sec and a peeling angle of 180 degrees with respect to the surface opposite to the surface of the substrate layer on which the pressure-sensitive adhesive layer is formed, and X.sub.2 is a peeling strength measured with respect to glass at room temperature and at a peeling rate of 5 mm/sec and a peeling angle of 180 degrees, wherein the X.sub.1 is 20 gf/25 mm or less.

2. The swelling tape for filling a gap of claim 1, wherein the swelling tape is deformed into a three-dimensional shape having a height of 0.001 mm to 2.00 mm in a direction perpendicular to the length direction of the substrate layer upon contact with the fluid.

3. The swelling tape for filling a gap of claim 1, wherein the substrate layer has a deformation ratio in the length direction according to Equation 2 of 10% or more:
Deformation ratio in length direction=(L.sub.2L.sub.1)/L.sub.1100[Equation 2] where L.sub.1 is an initial length before the substrate layer is in contact with the fluid, and L.sub.2 is a length of the substrate layer measured at room temperature or 60 C. after the substrate layer has been in contact with the fluid for 24 hours.

4. The swelling tape for filling a gap of claim 1, wherein the substrate layer comprises thermoplastic polyurethane.

5. The swelling tape for filling a gap of claim 1, wherein the pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, an epoxy pressure-sensitive adhesive, a silicon pressure-sensitive adhesive, or a rubber pressure-sensitive adhesive.

6. The swelling tape for filling a gap of claim 1, wherein the pressure-sensitive adhesive layer comprises an acrylic polymer crosslinked with a multifunctional crosslinking agent.

7. The swelling tape for filling a gap of claim 1, wherein the pressure-sensitive adhesive layer is attached to and wound around the surface opposite to the surface of the substrate layer on which the pressure-sensitive adhesive layer is formed.

8. The swelling tape for filling a gap of claim 1, wherein the X.sub.2 is 100 gf/25 mm or more.

9. A method of filling a gap formed between a first substrate and a second substrate spaced apart from the first substrate, comprising: attaching the pressure-sensitive adhesive layer of the swelling tape of claim 1 to the first or second substrate; and contacting the substrate layer of the swelling tape of claim 1 with a fluid.

10. The method of filling a gap of claim 9, wherein either one of the first and second substrates is an electrode assembly, and the other is a can encasing the assembly.

11. An electrode assembly having a circumferential surface to which the swelling tape of claim 1 is attached.

12. A battery, comprising: the electrode assembly of claim 11; a can encasing the assembly; and an electrolyte in contact with the assembly in the can.

13. The battery of claim 12, wherein the swelling tape of the electrode assembly fixes the assembly to an inside of the can by deforming into a three-dimensional shape upon contact with the electrolyte.

14. The battery of claim 13, wherein the electrolyte is a carbonate-based electrolyte.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a cross-sectional view of a swelling tape.

(2) FIG. 2 is a diagram showing a wound state of the swelling tape.

(3) FIG. 3 is a diagram showing a process of deforming the swelling tape into a three-dimensional shape.

(4) FIG. 4 is a diagram showing a process of deforming the swelling tape into a three-dimensional shape in the manufacture of a battery.

MODES OF INVENTION

(5) Hereinafter, a swelling tape will be described in detail with reference to Examples and Comparative Examples, and the scope of the swelling tape is not limited to the following Examples.

(6) In the Examples and Comparative Examples, physical properties are evaluated by the following methods.

(7) 1. Measurement of Deformation Ratio of Substrate Layer in Length Direction

(8) A specimen was manufactured by cutting a substrate layer to have a horizontal length of 10 mm, and a vertical length of 50 mm. The specimen was immersed in a carbonate-based electrolyte, left in a sealed state at room temperature for one day, and taken out of the electrolyte to measure a length in a vertical direction of the specimen and a deformation ratio in a length direction of the substrate layer according to Equation A.
Deformation ratio in length direction=(L.sub.2L.sub.1)/L.sub.1100[Equation A]

(9) In Equation A, L.sub.1 is an initial length in a vertical direction of the substrate layer before immersion in the electrolyte, that is, 50 mm, and L.sub.2 is a length in a vertical direction of the substrate layer measured after immersion in the electrolyte.

(10) 2. Measurement of Peeling Strength of Swelling Tape

(11) A specimen was manufactured by cutting a swelling tape to have a horizontal length of 25 mm and a vertical length of 200 mm. The sample was attached to a glass plate with a pressure-sensitive adhesive layer using a 2 kg rubber roller, and peeling strength was measured while the swelling tape was peeled off using a tensile tester at room temperature and at a peeling rate of 5 mm/sec and a peeling angle of 180 degrees.

(12) 3. Evaluation of Ability of Swelling Tape to Form Three-Dimensional Shape

(13) Batteries manufactured in the Examples and Comparative Examples were stored at room temperature for one day, disassembled to take an electrode assembly out from the battery, and a state of the swelling tape attached to the electrode assembly was evaluated, thereby evaluating ability to form a three-dimensional shape according to the following criteria.

(14) <Criteria for Evaluating Ability to Form Three-Dimensional Shape>

(15) : three-dimensional shape of the swelling tape was observed

(16) : three-dimensional shape of the swelling tape was not observed

(17) x: three-dimensional shape of the swelling tape was not observed, and the tape had peeled off of the electrode assembly

(18) 4. Evaluation of Gap-Filling Ability (Electrode Assembly Movement Preventing Ability) of Swelling Tape

(19) Gap-filling ability of the swelling tape was evaluated by a method of evaluating a movement preventing characteristic of the electrode assembly. In this method, for example, a low vibration evaluating method and a low impact evaluating method were included. In the low vibration method, a method for a vibration test was according to the UN38.3 specification, and when the battery was cut-off after evaluation, it was determined as cutting-off of a terminal by movement. In the low impact evaluation method, when the battery was put into an octagonal cylinder, rotated, and cut-off after predetermined time passed, it was determined as cutting-off of a terminal by movement. The gap-filling ability of the swelling tape evaluated by the above-described method was evaluated according to the following criteria.

(20) <Criteria for Evaluation of Gap-Filling Ability>

(21) : power of the battery was measured after evaluation of low vibration and low impact

(22) : power of the battery was measured after evaluation of low vibration and low impact, but resistance increased by 10% or more

(23) x: power of the battery was not measured after evaluation of low vibration and low impact

(24) 5. Measurement of Back-Side Peeling Ability

(25) A pressure-sensitive adhesive layer of the manufactured swelling tape was attached to an aluminum plate. In this operation, the tape was cut to have a horizontal length of 70 mm and a vertical length of 150 mm before use. Afterward, an identical swelling tape was attached again to a top surface of the attached tape. In this operation, the tape was cut to have a horizontal length of 25 mm, and a vertical length of 130 mm before use. After the attachment of the second tape, the aluminum plate was fixed at room temperature, and the second tape was bent at 180 degrees and then fixed to a PET film. Subsequently, back-side peeling strength was evaluated by peeling the second tape at a peeling rate of 5 mm/sec.

(26) For reproducibility, peeling strengths were evaluated with respect to the same specimen 5 to 10 times, and the average of the measured peeling strengths were listed below.

Example 1

(27) Manufacture of Swelling Tape

(28) A non-extensible film manufactured of thermoplastic polyurethane (TPU) and having a thickness of about 40 m was used as a substrate layer. A pressure-sensitive adhesive layer having a peeling strength with respect to a SUS plate of 600 gf/25 mm and a thickness of 15 m was formed on one surface of the substrate layer as an acrylic-based pressure-sensitive adhesive layer including 100 parts by weight of an acrylic pressure-sensitive adhesive resin crosslinked with about 0.2 parts by weight of an isocyanate crosslinking agent. Afterward, in consideration of a desired back-side peeling strength (20 gf/25 mm) of a surface of the substrate layer opposite to a surface having the pressure-sensitive adhesive layer, a back-side coating layer was formed as a fluorine-based releasing agent, resulting in manufacture of a swelling tape.

(29) Manufacture of Electrode Assembly and Battery

(30) The swelling tape was attached to cover an area corresponding to about 50% of a circumference of an electrode assembly (cross-sectional diameter: 17.2 mm) formed in a jelly roll type and including a cathode, an anode and a separator, and the assembly was inserted into a cylindrical can (cross-sectional diameter: 17.5 mm). Subsequently, a carbonate-based electrolyte was injected into the can and the can was sealed, thereby completing a battery.

Example 2

(31) Manufacture of Swelling Tape

(32) A non-extensible film manufactured of thermoplastic polyurethane (TPU) and having a thickness of about 40 m was used as a substrate layer. A pressure-sensitive adhesive layer having a peeling strength with respect to a SUS plate of 595 gf/25 mm and a thickness of 15 m was formed on one surface of the substrate layer as an acrylic-based pressure-sensitive adhesive layer including 100 parts by weight of an acrylic pressure-sensitive adhesive resin crosslinked with about 0.2 parts by weight of an isocyanate crosslinking agent. Afterward, in consideration of a desired back-side peeling strength (20 gf/25 mm) of a surface of the substrate layer opposite to a surface having the pressure-sensitive adhesive layer, a back-side coating layer was formed as a silicon-based releasing agent, resulting in manufacture of a swelling tape.

(33) Manufacture of Electrode Assembly and Battery

(34) The swelling tape was attached to cover an area corresponding to about 50% of a circumference of an electrode assembly (cross-sectional diameter: 17.2 mm) formed in a jelly roll type and including a cathode, an anode and a separator, and the assembly was inserted into a cylindrical can (cross-sectional diameter: 17.5 mm). Subsequently, a carbonate-based electrolyte was injected into the can and the can was sealed, thereby completing a battery.

Example 3

(35) Manufacture of Swelling Tape

(36) A non-extensible film manufactured of thermoplastic polyurethane (TPU) and having a thickness of about 40 m was used as a substrate layer. A pressure-sensitive adhesive layer having a peeling strength with respect to a SUS plate of 600 gf/25 mm and a thickness of 15 m was formed on one surface of the substrate layer as an acrylic-based pressure-sensitive adhesive layer including 100 parts by weight of an acrylic pressure-sensitive adhesive resin crosslinked with about 0.2 parts by weight of an isocyanate crosslinking agent. Afterward, in consideration of a desired back-side peeling strength (10 gf/25 mm) of a surface of the substrate layer opposite to a surface having the pressure-sensitive adhesive layer, a back-side coating layer was formed as an aliphatic releasing agent, resulting in manufacture of a swelling tape.

(37) Manufacture of Electrode Assembly and Battery

(38) The swelling tape was attached to cover an area corresponding to about 50% of a circumference of an electrode assembly (cross-sectional diameter: 17.2 mm) formed in a jelly roll type and including a cathode, an anode and a separator, and the assembly was inserted into a cylindrical can (cross-sectional diameter: 17.5 mm). Subsequently, a carbonate-based electrolyte was injected into the can and the can was sealed, thereby completing a battery.

Comparative Example 1

(39) Manufacture of Swelling Tape

(40) A non-extensible film manufactured of thermoplastic polyurethane (TPU) and having a thickness of about 40 m was used as a substrate layer. A pressure-sensitive adhesive layer having a peeling strength with respect to a SUS plate of 605 gf/25 mm and a thickness of 15 m was formed on one surface of the substrate layer as an acrylic-based pressure-sensitive adhesive layer including 100 parts by weight of an acrylic pressure-sensitive adhesive resin crosslinked with about 0.2 parts by weight of an isocyanate crosslinking agent, resulting in manufacture of a swelling tape. Separate releasing treatment was not performed on the substrate layer, and a measured back-side peeling strength was 500 gf/25 mm.

(41) Manufacture of Electrode Assembly and Battery

(42) The swelling tape was attached to cover an area corresponding to about 50% of a circumference of an electrode assembly (cross-sectional diameter: 17.2 mm) formed in a jelly roll type and including a cathode, an anode and a separator, and the assembly was inserted into a cylindrical can (cross-sectional diameter: 17.5 mm). Subsequently, a carbonate-based electrolyte was injected into the can and the can was sealed, thereby completing a battery.

Comparative Example 2

(43) Manufacture of Swelling Tape

(44) A non-extensible film manufactured of thermoplastic polyurethane (TPU) and having a thickness of about 40 m was used as a substrate layer. A pressure-sensitive adhesive layer having a peeling strength with respect to a SUS plate of 100 gf/25 mm and a thickness of 15 m was formed on one surface of the substrate layer as an acrylic-based pressure-sensitive adhesive layer including 100 parts by weight of an acrylic pressure-sensitive adhesive resin crosslinked with about 2 parts by weight of an isocyanate crosslinking agent, resulting in manufacture of a swelling tape. Separate releasing treatment was not performed on the substrate layer, and a measured back-side peeling strength was 70 gf/25 mm.

(45) Manufacture of Electrode Assembly and Battery

(46) The swelling tape was attached to cover an area corresponding to about 50% of a circumference of an electrode assembly (cross-sectional diameter: 17.2 mm) formed in a jelly roll type and including a cathode, an anode and a separator, and the assembly was inserted into a cylindrical can (cross-sectional diameter: 17.5 mm). Subsequently, a carbonate-based electrolyte was injected into the can and the can was sealed, thereby completing a battery.

(47) Physical properties measured in Examples and Comparative Examples are summarized and listed in Table 1.

(48) TABLE-US-00001 TABLE 1 Examples Comparative Examples 1 2 3 1 2 Substrate deformation 16 16 16 16 16 ratio (%) Peeling strength to 570 550 580 550 50 glass (gf/25 mm) Back-side peeling 20 20 10 500 70 strength (gf/25 mm) Unwinding property Smoothly Smoothly Smoothly Failed Smoothly unwound unwound unwound unwound Three-dimensional x shape implementing ability Gap-filling ability x (Movement preventing ability) Movement preventing Failed, 0 Failed, 0 Failed, 0 Failed, 0 Failed, 3 test performed to 10 samples Failed in unwinding property: winkles were generated on the film in evaluation of an unwinding property

EXPLANATION OF MARKS

(49) 10: pressure-sensitive adhesive layer 20: substrate layer 103, 104: objects forming a gap 101: swelling tape before implementation of three-dimensional shape 102: swelling tape after implementation of three-dimensional shape 2: swelling tape 201: substrate layer 202: pressure-sensitive adhesive layer 51a, 51b: swelling tape 52: can 53: electrode assembly