Flame-retardant hot-melt pressure-sensitive adhesive composition, and methods and articles containing the same.

Abstract

A flame-retardant hot-melt pressure-sensitive adhesive composition comprising a styrene-based block copolymer, a tackifier, a phosphinate, a polyphosphate, an optional swelling agent, and an optional plasticizer.

Description

Technical Field

[0001] The present invention relates to a flame-retardant hot-melt pressure-sensitive adhesive composition.

Background Art

[0002] Hot-melt pressure-sensitive adhesive compositions are often applied using a spray coater. However, in order for a hot-melt pressure-sensitive adhesive composition to be applied using spray coating technology, the viscosity of the composition must be sufficiently low at the application temperature, i.e., the temperature of the composition at the time of discharge from the application head.

[0003] Hot-melt pressure-sensitive adhesive compositions are solid at room temperature, melt when heated, and are flammable.

[0004] Flame retardants are often in the form of solid particles. When solid particles are added to a hot-melt adhesive composition, the solid particles increase the viscosity of the composition. The solid particles may also adversely affect the adhesion properties of the adhesive composition.

[0005] There is a need for a flame-retardant hot-melt pressure-sensitive adhesive composition having good adhesion properties and a sufficiently low viscosity to be applied using a commercially available hot-melt spray coater. Depending on the application, a flame-retardant hot-melt pressure-sensitive adhesive composition that does not contain a halogen-based flame retardant is required.

Prior Art Documents

Non-Patent Documents

[0006]

Non-Patent Document 1

Non-Patent Document 2

[0007] In one embodiment, the present invention is characterized by a flame-retardant hot-melt pressure-sensitive adhesive composition comprising a styrene-based block copolymer, a tackifier, a phosphinate, and a polyphosphate, wherein the flame-retardant hot-melt pressure-sensitive adhesive composition passes both the flammability I test and the flammability II test.

[0008] In another embodiment, the present invention is characterized by a flame-retardant hot-melt pressure-sensitive adhesive composition comprising a styrene-based block copolymer, a tackifier, a phosphinate, and a polyphosphate, wherein the hot-melt pressure-sensitive adhesive composition exhibits a viscosity of 20,000 centipoise (cP) or less, or even 15,000 cP or less, at 177°C.

[0009] In one embodiment, the flame-retardant hot-melt pressure-sensitive adhesive composition further comprises a plasticizer.

[0010] In another embodiment, the polyphosphate comprises a polyphosphate having a melting point of 120°C or less. In yet another embodiment, the polyphosphate comprises a first polyphosphate and a second polyphosphate different from the first polyphosphate, the second polyphosphate having a melting point of 120°C or less.

[0011] In some embodiments, the phosphinate includes an organic phosphinate. In other embodiments, the phosphinate includes a diethylphosphinate.

[0012] In one embodiment, the flame-retardant hot-melt pressure-sensitive adhesive composition further comprises a leavening agent, which is different from a polyphosphate. In some embodiments, the polyphosphate comprises ammonium polyphosphate, and the leavening agent comprises a melamine-derived leavening agent.

[0013] In other embodiments, the flame-retardant hot-melt pressure-sensitive adhesive composition further comprises components selected from the group consisting of metal oxides, carbon black, expansive graphite, and combinations thereof. In some embodiments, the components are selected from the group consisting of aluminum trihydrate, magnesium hydroxide, titanium dioxide, zinc borate, carbon black, expansive graphite, and combinations thereof.

[0014] In one embodiment, the styrene-based block copolymer includes a radial styrene-based block copolymer, a maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer, or a combination thereof.

[0015] In another embodiment, the flame-retardant hot-melt pressure-sensitive adhesive composition comprises 5% to 35% by mass of a styrene-based block copolymer, 5% to 40% by mass of a phosphinate, 3% to 40% by mass of a polyphosphate, and 10% to 65% by mass of a tackifier.

[0016] In other embodiments, the flame-retardant hot-melt pressure-sensitive adhesive composition comprises 10% to 30% by mass of a styrene-based block copolymer, 5% to 30% by mass of a phosphinate, 5% to 30% by mass of a polyphosphate, 10% to 65% by mass of a tackifier, and 5% to 30% by mass of a plasticizer.

[0017] In some embodiments, the flame-retardant hot-melt pressure-sensitive adhesive composition comprises 10% to 30% by mass of a styrene-based block copolymer, the styrene-based block copolymer comprising a radial block copolymer, 5% to 30% by mass of a phosphinate, 5% to 30% by mass of a polyphosphate, a leavening agent different from the polyphosphate, 10% to 65% by mass of a tackifier, and 5% to 30% by mass of a plasticizer.

[0018] In one embodiment, the flame-retardant hot-melt pressure-sensitive adhesive composition comprises 10% to 30% by mass of a styrene-based block copolymer, the styrene-based block copolymer comprising a radial block copolymer, 5% to 30% by mass of a phosphinate, 5% to 30% by mass of a polyphosphate, a different swelling agent than the polyphosphate, 10% to 65% by mass of a tackifier, 5% to 30% by mass of a plasticizer, and a flame retardant selected from the group consisting of metal oxides, carbon black, and combinations thereof.

[0019] In another embodiment, the polyphosphate comprises a first polyphosphate and a second polyphosphate different from the first polyphosphate, wherein the second polyphosphate has a melting point of 120°C or less, and the leavening agent is different from both the first and second polyphosphates.

[0020] In one embodiment, the sum of the mass of the phosphinate and the mass of the polyphosphate is 40% by mass or less relative to the mass of the flame-retardant hot-melt pressure-sensitive adhesive composition. In another embodiment, the sum of the mass of the phosphinate and the mass of the polyphosphate is 30% by mass or less relative to the mass of the flame-retardant hot-melt pressure-sensitive adhesive composition.

[0021] In other embodiments, the composition exhibits a peel force of at least 1.16 N / cm when tested according to the 180-degree peel adhesion test method.

[0022] In some embodiments, the composition exhibits a maximum debonding force of at least 2.94 N when tested according to the loop tack test method.

[0023] In one embodiment, the composition has a shear adhesion failure temperature of at least 50 °C.

[0024] In another embodiment, the composition passes the flammability I test method. In other embodiments, the composition passes the flammability II test method. In some embodiments, the composition passes both the flammability I test method and the flammability II test method.

[0025] In one embodiment, the composition exhibits a viscosity of 8000 cP or less, or even 6000 cP or less, at 177 °C.

[0026] In another embodiment, the present invention is characterized by a process for applying a flame-retardant hot-melt pressure-sensitive adhesive composition onto a battery cell, the process comprising the steps of discharging the flame-retardant hot-melt pressure-sensitive adhesive composition from an application head in the form of a spray, and forming an adhesive coating on the surface of a first battery cell, wherein the forming step includes bringing the surface of the battery cell into contact with the spray of the flame-retardant hot-melt pressure-sensitive adhesive composition without the application head touching the surface of the battery cell. In one embodiment, the process further comprises the step of bringing the adhesive coating of the first battery cell into contact with the adhesive coating of the second battery cell to bond the first battery cell to the second battery cell. In another embodiment, the process further comprises the step of bringing the adhesive coating of the first battery cell into contact with the outer surface of the second battery cell to bond the first battery cell to the second battery cell. In some embodiments, the first battery cell includes a pouch made of a multilayer film including a first outer film layer, the first outer film layer comprising nylon, polyethylene terephthalate, or polypropylene, and a spray of the adhesive composition comes into contact with the first outer film layer. In one embodiment, the spray of the adhesive composition is in a form selected from the group consisting of fibrous, foamy, helical, and combinations thereof.

[0027] In other embodiments, the present invention features a battery cell array comprising a first battery cell, a second battery cell, and a flame-retardant pressure-sensitive hot-melt adhesive composition disclosed herein, wherein the first battery cell is bonded to the second battery cell via the flame-retardant pressure-sensitive hot-melt adhesive composition. [Means for solving the problem]

[0028] The present invention features a hot-melt pressure-sensitive adhesive composition that exhibits good adhesion and good flame retardancy and can be applied using a spray coating method.

[0029] Other features and advantages will become apparent from the following description of preferred embodiments and claims.

[0030] Glossary In relation to the present invention, these terms have the meanings set forth below.

[0031] The term "flame retardant" refers to the ability to slow down the spread of fire.

[0032] "Expanding" means that when exposed to high temperatures or flames, the volume expands and carbonizes.

[0033] The term "hot melt pressure-sensitive adhesive composition" refers to a pressure-sensitive adhesive composition that is solid at room temperature and becomes fluid when heated. [Modes for carrying out the invention]

[0034] The flame-retardant hot-melt pressure-sensitive adhesive composition comprises a styrene-based block copolymer, a tackifier, a phosphinate, and a polyphosphate. The flame-retardant hot-melt pressure-sensitive adhesive composition expands when exposed to flame. Preferably, the flame-retardant hot-melt pressure-sensitive adhesive composition passes at least one of the UL 94 V0 test method and the UL 510A test method, and more preferably, passes both the UL 94 V0 test method and the UL 510A test method. The flame-retardant hot-melt pressure-sensitive adhesive composition preferably does not contain components with a flash point below 121°C. The flame-retardant hot-melt pressure-sensitive adhesive composition preferably does not contain halogenated flame retardants and can be formulated to be halogenated flame retardant-free and to pass at least one of the UL 94 V0 test method and the UL 510A test method.

[0035] A flame-retardant hot-melt pressure-sensitive adhesive composition can be formulated to exhibit any suitable viscosity at 177°C, for example, including 50,000 centipoise (cP) or less, 20,000 cP or less, 15,000 cP or less, 10,000 cP or less, 8,000 cP or less, 6,000 cP or less, at least 500 cP, at least 1,000 cP, 2,000 cP to 15,000 cP, 2,000 cP to 6,000 cP, 2,000 cP to 5,000 cP, or even 3,000 cP to 6,000 cP. A useful flame-retardant hot-melt pressure-sensitive adhesive composition exhibits a viscosity of 10,000 centipoise (cP) or less at 177°C, or even a viscosity of 6,000 cP or less at 177°C.

[0036] Flame-retardant hot-melt pressure-sensitive adhesive compositions are tacky to the touch at room temperature and preferably exhibit sufficient adhesive strength and cohesive force to maintain a fixed relationship between two substrates. Useful measures of adhesive strength and cohesive force include loop tack, 180-degree peel adhesion, and shear adhesion failure temperature. Particularly useful flame-retardant hot-melt pressure-sensitive adhesive compositions exhibit a maximum delamination force of at least 300 gram-force (gf) (2.94 Newtons (N)), at least 700 gf (6.86 N), at least 1000 gf (9.8 N), at least 2000 gf (19.6 N), or even at least 3000 gf (29.4 N) when tested according to the loop tack test; a 180-degree peel force of at least 300 gf / inch (gf / in) (1.16 Newtons / centimeter (N / cm)), at least 500 gf / in (1.93 N / cm), or even at least 700 gf / in (2.7 N / cm) when tested according to the 180-degree peel adhesion test; and a shear adhesion failure temperature of at least 50°C, at least 60°C, or even at least 65°C when tested according to the shear adhesion failure temperature (SAFT) test, or a combination of these properties.

[0037] Styrene-based block copolymers The flame-retardant hot-melt pressure-sensitive adhesive composition contains a styrene-based block copolymer, preferably containing at least one radial styrene-based block copolymer. The styrene-based block copolymer is derived from a styrene-based monomer and at least one comonomer, the monomers being present in block form.

[0038] A styrene-based block copolymer comprises at least one styrene-based terminal block (A), at least one intermediate block (midblock) (B), and an optional maleic anhydride graft modifier. The styrene-based block copolymer can exhibit any structure, including, for example, linear, radial, and star-shaped structures, which include, for example, styrene-based diblock copolymers of formula AB, linear triblock copolymers of formula ABA, linear A-(BA)nB multiblock copolymers, linear tetrablock copolymers of formulas such as ABAB and ABABA, pentablock copolymers having formulas (AB)nY, and combinations thereof, where A is a monoalkenyl aromatic hydrocarbon block, B is a conjugated diene or sesquiterpene block, Y is a polyvalent compound, and n is at least an integer of 3.

[0039] Examples of useful styrene-based terminal blocks (A) include styrene, alpha-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, ethylstyrene, propylstyrene, butylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, 2,4,6-trimethylstyrene, vinyltoluene, 1,1-vinylbiphenyl, vinylnaphthalene, vinylanthracene, and combinations thereof.

[0040] Useful types of intermediate block (B) include, for example, elastomer-conjugated dienes (e.g., hydrogenated and non-hydrogenated conjugated dienes), sesquiterpenes (e.g., hydrogenated and non-hydrogenated sesquiterpenes), and combinations thereof. Suitable conjugated dienes include, for example, butadiene (e.g., polybutadiene), isoprene (e.g., polyisoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1-phenyl-1,3-butadiene, 3-butyl-1,3-octadiene, myrcene, farnesene, 1,3-cyclohexadiene, piperylene, and combinations thereof, as well as hydrogenated versions thereof, including, for example, ethylene, propylene, butylene, and combinations thereof (e.g., ethylene / butylene and ethylene / propylene). A suitable sesquiterpene is, for example, beta-farnesene. The intermediate block may further include monomer units or blocks derived from monomer units as identified above, for example, as useful for styrene-based terminal blocks (A) containing styrene.

[0041] Useful styrene-based block copolymers include, for example, radial styrene-butadiene block copolymer, random styrene-butadiene block copolymer, styrene-butadiene block copolymer, multi-arm styrene-butadiene block copolymer, styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, styrene-isobutylene-styrene block copolymer, styrene-isoprene block copolymer, styrene-isoprene-styrene block copolymer, styrene-multi-arm styrene-isoprene(SI)x block copolymer, and hydrogenated styrene-based block copolymers (e.g., styrene-ethylene-butylene- Examples include styrene, styrene-ethylene-propylene-styrene, styrene-ethylene-butylene-styrene-styrene, styrene-ethylene-ethylene-propylene-styrene, styrene-ethylene-butylene-styrene-styrene, and combinations thereof), maleic anhydride-modified styrene-based block copolymers (e.g., maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer, maleic anhydride-modified styrene-ethylene-propylene-styrene block copolymer, maleic anhydride-modified styrene-isoprene-styrene block copolymer, and maleic anhydride-modified styrene-butadiene-styrene block copolymer), and combinations thereof.

[0042] Useful styrene-based block copolymers are trademarked products of the KRATON D and G series from Kraton Corporation (Houston, Texas), including, for example, KRATON D 1124 branched styrene-isoprene block copolymer, D 1163 linear styrene-isoprene-styrene block copolymer, D 1117 linear styrene-isoprene-styrene block copolymer, and KRATON G 1652 styrene-ethylene-butylene-styrene block copolymer and G 1726 styrene-ethylene-butylene-styrene block copolymer, as well as Dynasol Elastomeros, Corp.Trademark names for the SOLPRENE and CALPRENE series, including SOLPRENE 1205, SOLPRENE 411, and CALPRENE 401 radial styrene block copolymers, from Tamaulipas, Mexico; trademark name for EUROPRENE Sol T from EniChem Corporation (Houston, Texas); trademark name for the FINAPRENE series, including FINAPRENE 401, from Total Petrochemicals USA, Inc. (Houston, Texas); trademark name for the SEPTON series, including SEPTON S 1001 styrene-ethylene-propylene-styrene block copolymer and SEPTON 4030, 4033, 4044, 4055, and 4077 block copolymers, from Septon Company of America, Inc. (Pasadena, Texas); and trademark names for VECTOR 4211A and VECTOR from Taiwan Synthetic Rubber Corporation, Inc. (Taipei City, Taiwan). It is marketed under the trademark names VECTOR series containing 4411A styrene-isoprene-styrene block copolymer, the TAIPOL series from Taiwan Synthetic Rubber Corporation containing TAIPOL 7126 maleate-modified maleic anhydride styrene-ethylene-butylene-styrene block copolymer and TAIPOL 7131 maleate-modified maleic anhydride styrene-ethylene-butylene-styrene block copolymer, the FG trademark from Kraton Corporation containing FG 1901 maleate-modified maleic anhydride styrene-ethylene-butylene-styrene block copolymer, and the M trademark from Asahi Kasei Corporation (Tokyo, Japan) containing M1913 maleate-modified maleic anhydride styrene-ethylene-butylene-styrene block copolymer.

[0043] The composition contains 5% to 35% by mass, 5% to 30% by mass, 10% to 30% by mass, or even 15% to 30% by mass of a styrene-based block copolymer.

[0044] The composition preferably contains 0% to 20% by mass, 2% to 20% by mass, 2% to 15% by mass, or even 5% to 15% by mass of a radial styrene block copolymer.

[0045] Tackifier Tackifiers can be solid or liquid at room temperature, and compositions may include combinations of solid and liquid tackifiers. Useful types of tackifiers include, for example, aromatic, aliphatic, and cyclic aliphatic hydrocarbon resins, mixed aromatic and aliphatic modified hydrocarbon resins, aromatic modified aliphatic hydrocarbon resins, and their hydrogenated versions; terpenes, modified terpenes, and their hydrogenated versions; natural rosins, modified rosins, rosin esters, and their hydrogenated versions; and combinations thereof.

[0046] Useful types of hydrocarbon resins include, for example, branched, unbranched, and cyclic C5 resins, C9 resins, C10 resins, C5 / C9 resins, hydrogenated C5 resins, hydrogenated C9 resins, hydrogenated dicyclopentadiene (DCPD), and combinations thereof.

[0047] Useful hydrocarbon tackifiers include various brand names, such as the PLASTOLYN and ENDEX series from Synthomer PLC (London, United Kingdom), which include PLASTOLYN 290 aromatic hydrocarbon resin and ENDEX 160 HC aromatic hydrocarbon resin with a ring and ball softening point of 159°C; the HF series from Henghe Materials & Science Technology Co., Ltd. (Ningbo, China), which includes HF-100; the ESCOREZ series from ExxonMobil Chemical Company (Houston, Texas), which includes ESCOREZ 1310LC, ESCOREZ 5400, ESCOREZ 5415, ESCOREZ 5600, ESCOREZ 5615, ESCOREZ 5637, and ESCOREZ 5690; and EASTOTAC from Synthomer PLC (London, United Kingdom). The EASTOTAC series of trademarks, including H-100R, EASTOTAC H-100L, EASTOTAC H-100W, and EASTOTAC H130W; the WINGTACK series of trademarks from Cray Valley HSC (Exton, Pennsylvania), including WINGTACK 86 Aromatic Modified C-5 Hydrocarbon Resin, WINGTACK EXTRA Aromatic Modified C-5 Hydrocarbon Resin, WINGTACK 95 Aliphatic C-5 Petroleum Hydrocarbon Resin, and WINGTACK 10 Liquid Aliphatic Resin; the PICCOTAC series of trademarks from Synthomer PLC (London, United Kingdom), including, for example, PICCOTAC 8095 Aromatic Modified C-5 Hydrocarbon Resin and 1115 Hydrocarbon Resin; the ARKON series of trademarks from Arakawa Europe GmbH (Germany), including, for example, ARKON P-100 Hydrogenated Hydrocarbon Resin and ARKON P-125 Alicyclic Saturated Hydrocarbon Resin; and Resinall Corp.These products are marketed under the RESINALL brand name, including RESINALL 1030 hydrogenated hydrocarbon resin, by the company (Severn, North Carolina), and under the REGALITE and REGALREZ series brand names, including, for example, REGALITE R1125 fully hydrogenated hydrocarbon resin and REGALREZ 1126 hydrocarbon resin, by Eastman Chemical Company.

[0048] Useful rosin-based tackifiers include rosin acid, rosin esters, wood rosin, tall oil rosin, gum rosin, distilled rosin, hydrogenated rosin, dimerized rosin, polymerized rosin, and combinations thereof. Examples of useful rosin esters include, for example, glycerol esters of pale wood rosin, glycerol esters of hydrogenated rosin, glycerol esters of polymerized rosin, pentaerythritol esters of natural and modified rosins including pentaerythritol ester of pale wood rosin, pentaerythritol esters of hydrogenated rosin, pentaerythritol esters of tall oil rosin, phenol-based modified pentaerythritol esters of rosin, and combinations thereof.

[0049] Useful commercially available rosin-based tackifiers include various brand names, such as the SYLVALITE and SYLVATAC series from Kraton Corporation (Houston, Texas), including SYLVALITE RE-100L rosin ester, SYLVALITE 9100 rosin ester, and SYLVATAC RE 25 rosin ester; KOMOTAC KA100L gum rosin pentaerythritol ester from Komo Pine Chemicals, Guangzhou Komo Chemical Co., Ltd (China); the WESTREZ and ALTATAC series from Ingevity Corp. (North Charleston, South Carolina), including WESTREZ 5101, WESTREZ 5295, and ALTATAC 1000 rosin ester; and FORAL 105-E gum rosin and FORAL from Eastman (Kingsport, Tennessee). It is available under the trademark name FORAL series containing AX rosin acid, and under the trademark name TECKROS series containing, for example, TECKROS D85 and D95 ​​rosin esters from Teckrez Inc. (Fleming Island, Florida).

[0050] Examples of useful polyterpene resins include terpene phenol resins, non-hydrogenated polyterpene resins, hydrogenated polyterpene resins, and copolymers and terpolymers of natural terpenes (e.g., styrene-terpene, alpha-methylstyrene-terpene, and vinyltoluene-terpene), as well as combinations thereof. Polyterpene resins are marketed under various brand names, such as the SYLVARES series from Kraton Corp. (Houston, Texas), which includes SYLVARES 6100 terpene resin and SYLVAREZ TRM1115 polyterpene resin, and the DERCOLYTE series from DRT Company (Dax, France), which includes, for example, DERCOLYTE A115 terpene resin.

[0051] The composition contains 10% to 65% by mass, 15% to 55% by mass, or even 25% to 50% by mass of a tackifier.

[0052] Phosphate Useful phosphinates include organic phosphinates, inorganic phosphinates, diphosphinates, and combinations thereof. Useful metal ions in phosphinates are derived from a variety of metals, including, for example, alkali metals, alkaline earth metals, transition metals, post-transition metals, metalloids, and combinations thereof, such as lithium, sodium, potassium, magnesium, calcium, titanium, manganese, iron, zinc, zirconium, aluminum, germanium, tin, antimony, and bismuth.

[0053] Useful organic phosphinates include, for example, alkyl and dialkylphosphinates containing aluminum dialkylphosphinate (e.g., diethylaluminum phosphinate).

[0054] Examples of useful inorganic phosphinates include aluminum phosphinate and zinc phosphinate.

[0055] The phosphinate preferably has a median particle size of 50 microns (μm) or less, 20 μm or less, 15 μm or less, or even 10 μm or less.

[0056] Useful phosphinates are marketed under various brand names, such as the EXOLIT series from Clariant Corporation (Germany), which includes EXOLIT OP 945 diethylaluminum phosphinate, EXOLIT OP 930 phosphinate, EXOLIT OP 935 phosphinate, EXOLIT OP 1311 phosphinate, EXOLIT OP 1248 phosphinate, and EXOLIT OP 1230 phosphinate.

[0057] The composition contains 5% to 40% by mass, 5% to 30% by mass, 5% to 20% by mass, or even 10% to 20% by mass of phosphinate salts.

[0058] polyphosphate A polyphosphate is a salt or ester of phosphate containing at least two phosphate units in a linear or cyclic structure. Useful salts of phosphate include cationic moieties (e.g., ammonia, melamine, and combinations thereof). The flame-retardant hot-melt pressure-sensitive adhesive composition preferably contains at least one polyphosphate exhibiting a melting temperature of 120°C or less, or even 110°C or less.

[0059] Examples of useful polyphosphates include ammonium polyphosphate, melamine polyphosphate, hexaphenoxycyclotriphosphazene, and combinations thereof.

[0060] Specific examples of suitable polyphosphate esters include tetrakis(2,6-dimethylphenyl)-m-phenylene bisphosphate, resorcinol bis(diphenyl phosphate) (RDP), bisphenol A bis(diphenyl phosphate), biphosphate resorcinol bis(dixylenyl phosphate), and combinations thereof.

[0061] The polyphosphate preferably has a median particle size of 50 μm or less, 20 μm or less, 15 μm or less, or even 10 μm or less.

[0062] Useful polyphosphates include the PHOSGARD series of trademarks, such as PHOSGARD 200 tetrakis(2,6-dimethylphenyl)-m-phenylenebisphosphate from St. Louis Group LLC (Indianapolis, Indiana), PHOSGARD 300 polyphosphate flame retardant system, which the manufacturer reports to have a phosphorus content of 28% to 32%, PHOSGARD 700 polyphosphate and nitrogen flame retardant system, which the manufacturer reports to have a phosphorus content of 17% to 22% and a nitrogen content of 21% to 23%, and PHOSGARD APP-HP ammonium polyphosphate flame retardant, which the manufacturer reports to have a phosphorus content of at least 31% and a nitrogen content of 14% to 15%, MELAPUR polyphosphate melamine from BASF Group (Florham Park, New Jersey), and ICL - Industrial Products Group. It is marketed under the trademark name FYROFLEX series by Ltd. (Israel), containing FYROFLEX RDP-HP resorcinol bis(diphenyl phosphate), which the manufacturer reports to have a phosphorus content of 10.7% by mass, and FYROFLEX SOL-DP phosphate ester flame retardant, which the manufacturer also reports to have a phosphorus content of 10.7% by mass.

[0063] The flame-retardant hot-melt pressure-sensitive adhesive composition comprises at least 3% by mass, at least 5% by mass, 3% to 40% by mass, 3% to 30% by mass, 5% to 30% by mass, 3% to 15% by mass, or further 3% to 10% by mass of polyphosphate, and optionally 0% to 20% by mass, 3% to 20% by mass, 5% to 15% by mass, or further 5% to 10% by mass of polyphosphate having a melting temperature of 120°C or less, or further 110°C or less.

[0064] optional additional ingredients The composition optionally includes additional components, such as leavening agents, additional flame retardant components, plasticizers, stabilizers, antioxidants, additional polymers, adhesion promoters, UV stabilizers (e.g., TINUVIN P from BASF Corporation), rheology modifiers, corrosion inhibitors, colorants (e.g., pigments and dyes), fillers, fragrances, additional flame retardants, and combinations thereof.

[0065] leavening agent Useful leavening agents decompose (or sublimate) when exposed to flame, temperatures above 200°C, or both, releasing gas and increasing in volume. Preferred leavening agents decompose at temperatures of at least 220°C, or even at least 250°C. Some useful types of leavening agents include, for example, melamine (i.e., 1,3,5-triazine-2,4,6-triamine), melam (i.e., (N2-(4,6-diamino-1,3,5-triazine-2-yl)-1,3,5-triazine-2,4,6-triamine), melem (i.e., 2,5,8-triamino-tri-s-triazine), and melon (i.e., H(-C6N8H2)-NH-) 10 Examples of melamine-derived leavening agents include (NH2), melamine phosphate, melamine pyrophosphate, melamine polyphosphate, melam polyphosphate, melem polyphosphate, melon polyphosphate, melamine cyanurate, and combinations thereof. Other useful leavening agents include, for example, dicyanoguanidine, phthalocyanine pigments, diazo compounds, expandable graphite, and combinations thereof.

[0066] Useful leavening agents are marketed under various brand names, such as the CHARFLAM series from St. Louis Group LLC (Indianapolis, Indiana), which includes CHARFLAM 200 polyphosphate melamine and the CHARFLAM series containing CHARFLAM 400, CHARFLAM 400W, and CHARFLAM 400D, which contain 1,3,5-triazine-2,4,6(1H,3H,5H)-trione and 1,3,5-triazine-2,4,6-triamine in a 1:1 ratio, as well as the GRAFGUARD series from NeoGraf Solutions, LLC (Lakewood, Ohio), which includes GRAFGUARD 200, 210, 220, 225, 250, and 280 expandable graphite flakes.

[0067] The flame-retardant hot-melt pressure-sensitive adhesive composition contains a leavening agent different from polyphosphate in an amount of 0% to 30% by mass, 5% to 20% by mass, or even 5% to 10% by mass.

[0068] Additional flame retardant components Useful additional flame retardant components include, for example, metal oxides (e.g., anhydrous metal oxides, metal hydroxides, and metal hydrates), carbon black, and combinations thereof. Suitable metal oxide flame retardants are derived from various elements, including, for example, aluminum, boron, calcium, magnesium, zinc, tin, titanium, cerium, and combinations thereof. Useful metal oxide flame retardants include, for example, magnesium hydroxide, titanium dioxide, zinc borate, zinc carbonate, zinc stanate, zinc hydrogen phosphate, zinc pyrophosphate, zinc oleate, zinc stearate, zinc phosphate, and combinations thereof.

[0069] Useful metal oxide flame retardants are commercially available under various brand names, including FIREBRAKE ZB zinc borate flame retardant and FIREBRAKE 500 anhydrous zinc borate flame retardant, both of which are available from, for example, US Borax Inc. (Boron, California).

[0070] Useful metal hydrate flame retardants include, for example, aluminum trihydrate, zinc borate, and combinations thereof.

[0071] The flame-retardant hot-melt pressure-sensitive adhesive composition contains any of these flame retardant components in amounts of 0% to 10% by mass, 0.1% to 10% by mass, 0.1% to 5% by mass, or even 0.1% to 2% by mass.

[0072] plasticizer Useful plasticizers include liquid plasticizers (i.e., plasticizers that are liquid at room temperature), solid plasticizers, and combinations thereof. Useful types of liquid plasticizers include, for example, oils, oligomers, and low molecular weight polymer plasticizers, and combinations thereof. Useful oils include, for example, hydrocarbon oils, mineral oils (e.g., white mineral oil), paraffinic oils, naphthenic oils, and GTL oils (gas to liquid). Examples of useful solid plasticizers include oils, synthetic liquid oligomers of polyolefins (e.g., oligomers of polypropylene, polybutene, polyisoprene, and hydrogenated polyisoprene), liquid polyisobutylene, polybutadiene, glycerol esters of fatty acids, polyesters (e.g., polyethylene glycol di-2-ethylhexoate), hydrocarbon fluids, benzoic acid esters (e.g., ethylene glycol dibenzoate, propylene glycol dibenzoate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, pentaerythritol tetrabenzoate), and derivatives thereof, as well as combinations thereof, oils derived from renewable resources (e.g., animal oils, vegetable oils (e.g., canola oil, corn oil, soybean oil, epoxidized soybean oil, palm oil, peanut oil, olive oil, sunflower oil, rapeseed oil, jatropha oil, coconut oil, and castor oil)), and combinations thereof. Examples of useful solid plasticizers include benzoic acid esters.

[0073] Suitable commercially available liquid plasticizers include, for example, KN40410 naphthenic oil from Petro China's Lube Oil Company (Beijing, China), CALSOL 5550 naphthenic oil and DRAKEOL 35 paraffinic oil from Calumet Specialty Products (Indianapolis, Indiana), NYFLEX 222B and NYFLEX 223 naphthenic oils from Nynas Naphthenic AB (Sweden), Dry #1 castor oil from Vertellus Performance Materials Inc. (Bayonne, New Jersey), PURETOL 35 paraffinic oil from Petro-Canada Lubricants Inc. (Ontario, Canada), CATENEX T145 paraffinic oil from Shell Oil Products US (Houston, Texas), KAYDOL mineral oil from Sonneborn (Petrolia, Pennsylvania), and Petrochem These products are marketed under various brand names, including KRYSTOL 550 mineral oil from Carless Limited (Surrey, England), RISELLA X430 natural gas GTL oil from Shell Oil Products US (Houston, Texas), BENZOFLEX 284, BENZOFLEX 9-88, and BENZOFLEX 2088 benzoate plasticizers from Eastman Specialties Holdings Corp. (Kingsport, Tennessee), HALLGREEN R-8010 renewable ester, PARAPLEX A-8000, and PARAPLEX A-8200 from Hallstar Industrial (Chicago, Illinois), and DYNACOLL 7250 and DYNACOLL 7230 polyester polyols from Evonik Industries AG (Essen, Germany).

[0074] A suitable example of a commercially available solid plasticizer is BENZOFLEX 352 benzoate ester plasticizer, available from Eastman Specialties Holdings Corp. (Kingsport, Tenn.).

[0075] The composition contains 0% to 30% by mass, 5% to 30% by mass, or even 5% to 20% by mass of a plasticizer.

[0076] Antioxidant Useful antioxidants include, for example, pentaerythritol tetrakis[3,(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2'-methylenebis(4-methyl-6-tert-butylphenol), phosphites including tris-(p-nonylphenyl)-phosphite (TNPP) and bis(2,4-di-tert-butylphenyl)4,4'-diphenylenediphosphonite, di-stearyl-3,3'-thiodipropionate (DSTDP), and combinations thereof. Useful antioxidants are commercially available under the IRGANOX series of trademark names, including, for example, IRGANOX 1010, IRGANOX 565, and IRGANOX 1076 hindered phenol antioxidants, as well as various trademark names including IRGAFOS 168 phosphite antioxidants, all of which are available from BASF Corporation (Florham Park, New Jersey). If present, the composition preferably contains about 0.02% to about 2% by mass of antioxidants.

[0077] use The composition is useful in various forms, including, for example, beads, spray patterns, coatings (e.g., continuous and discontinuous coatings (e.g., random, patterned, and arrayed)), films (e.g., continuous and discontinuous films), binders, fibers (e.g., random fibers), and foams. The composition can be applied to any desired thickness. Formulations of flame-retardant hot-melt pressure-sensitive adhesive compositions exhibiting sufficiently low viscosity can be applied using a spray application device to achieve relatively thin coating thicknesses, including, for example, 200 microns (μm) or less, 100 μm or less, 20 μm, 30 μm, 20 μm to 100 μm, 20 μm to 50 μm, or even 20 μm to 30 μm.

[0078] Hot melt adhesive compositions can be applied to various substrates, including, for example, films (e.g., polyolefin (e.g., polyethylene and polypropylene) films, polyester films (e.g., polybutylene terephthalate and polyethylene terephthalate), polyamide films (e.g., nylon, nylon 6, nylon 66, nylon 610, nylon 612, nylon 1,6, nylon 510, and copolymers thereof), and polyimide films), release liners, metals (e.g., stainless steel and aluminum), metal foils (e.g., aluminum foil and stainless steel foil), foams (e.g., polyurethane foams in various forms including sheets), and sheets (e.g., mica sheets). These can be incorporated and used to bond together one or more substrates, including, for example, stainless steel to stainless steel, polyethylene terephthalate to polyethylene terephthalate, polyethylene terephthalate to stainless steel, polyethylene terephthalate to mica sheet, polyethylene to polyethylene terephthalate, polypropylene to polyethylene terephthalate, polyamide to polyamide, polyethylene terephthalate to metal foil (e.g., aluminum foil), stainless steel to metal foil (e.g., aluminum foil), polyethylene to polyethylene, polyethylene to polypropylene, polypropylene to polypropylene, mica sheet to polyurethane foam, and combinations thereof.

[0079] Flame-retardant hot-melt pressure-sensitive adhesive compositions are also useful for bonding components within a battery pack. In one embodiment, a flame-retardant hot-melt pressure-sensitive adhesive composition is useful for bonding two battery cells together. In one embodiment, the flame-retardant hot-melt pressure-sensitive adhesive composition is applied to the outer surface of a first battery cell, and optionally the first battery cell to which the adhesive is applied comes into contact with a second battery cell (which may similarly be coated with the same or a different flame-retardant hot-melt pressure-sensitive adhesive composition), thereby bonding the two battery cells together and preferably preventing the battery cells from moving relative to each other. In this way, an array of multiple battery cells bonded together can be formed.

[0080] A suitable battery cell includes a sealed case that houses the electrolyte and electrode assembly. One useful type of sealable case includes a flexible polymer laminate (e.g., a multilayer film laminate). The flexible polymer laminate includes at least one outer polymer film layer, at least one inner metal foil layer (e.g., aluminum foil), and at least one inner polymer film layer. Both the outer and inner polymer layers include a single polymer film, and optionally include multiple polymer films. Each polymer film layer is formed from the same or different polymers, and optionally from a blend of different polymers. Suitable polymers for forming the outer polymer layer include, for example, polyamides (e.g., nylon, nylon 6, nylon 66, nylon 610, nylon 612, nylon 1,6, nylon 510, and copolymers thereof), polyimides, polyesters (e.g., polybutylene terephthalate and polyethylene terephthalate), polyolefins (e.g., polyethylene and polypropylene), and combinations thereof.

[0081] Suitable polymers for forming the inner polymer layer include, for example, polypropylene and polyethylene.

[0082] The internal metal foil layer comprises at least one metal foil layer, and may comprise multiple metal foil layers, which may be separated by at least one polymer film layer. A preferred metal foil layer is aluminum. Other preferred metal foil layers include, for example, stainless steel.

[0083] The battery and flexible polymer laminate exhibit any preferred structure, including, for example, a pouch, cylindrical, prismatic, coin-shaped, and combinations thereof.

[0084] The flame-retardant hot-melt pressure-sensitive adhesive composition is also useful for bonding batteries or battery arrays to a housing (e.g., a container), where the batteries or battery arrays are bonded to the housing via the flame-retardant hot-melt pressure-sensitive adhesive composition. The housing can be made of any suitable material, including, for example, metal (e.g., aluminum, stainless steel), plastic (e.g., polyethylene terephthalate, polyurethane, and polycarbonate), and combinations thereof.

[0085] The present invention will now be explained by the following examples. All parts, ratios, percentages, and quantities described in the examples are by mass unless otherwise specified. [Examples]

[0086] Test Procedure The test procedures used in the examples include the following. All ratios and percentages are by mass unless otherwise specified. The procedures are carried out at room temperature (i.e., room temperature of approximately 20°C to approximately 25°C) unless otherwise specified.

[0087] Flammability Test Method I: UL 94 V0 Test Method Flammability is determined according to UL94, titled "Standard for Safety Tests for Flammability of Plastic Materials for Parts in Devices and Appliances" (2013), with a sample thickness of 3 millimeters (mm). The results are reported as pass or fail.

[0088] Flammability Test Method II: UL 510A Test Method Flammability is determined according to UL 510A, titled "Standard for Safety Component Tapes." The result is reported as pass or fail.

[0089] Viscosity testing method Viscosity was determined at a temperature of 177°C using a Brookfield Thermosel viscometer Model RVDV 2 and SC4-27 spindle, according to ASTM D-3236, entitled "Standard Test Method for Apparent viscosity of Hot Melt Adhesives and Coating Materials" (April 1, 2015), excluding measurements performed within a torque range of 30% to 70%. Results were reported in centipoise (cP).

[0090] 180-degree peel test method The 180-degree peel strength is determined using two 50-micron (μm) polyethylene terephthalate films according to ASTM D3330-02, titled "Standard Test Method for Peel Adhesion of Pressure-Sensitive Tape." The results are reported in units of gram-force per inch (gf / in) or newtons per centimeter (N / cm).

[0091] 90-degree peel test method The 90-degree peel strength is determined using two 50-micron (μm) polyethylene terephthalate films according to Test Method F of ASTM D 3330-02, titled "Standard Test Method for Peel Adhesion of Pressure-Sensitive Tape." The results are reported in units of gram-force per inch (gf / in) or Newtons per centimeter (N / cm).

[0092] Shear Bond Failure Temperature (SAFT) Test Method The shear bond failure temperature is determined using two 50 μm polyethylene terephthalate films according to ASTM D 4498-00, titled "Standard Test Method for Heat-Fail Temperature in Shear of Hot Melt Adhesives." The results are reported in degrees Celsius (°C).

[0093] Loop tack test method Loop tack is determined using two 50 μm polyethylene terephthalate films according to ASTM D 6195-03, titled "Standard Test Method for Loop Tack". The maximum desorption force is reported in units of gram force (gf) or Newton (N), and the mode of failure is reported as adhesive, cohesive, or migratory.

[0094] (Examples 1-5) The hot-melt pressure-sensitive adhesive compositions of Examples 1-5 were prepared as follows. The non-meltable components of the compositions of Examples 1-5 were combined with components of compositions that are liquid at room temperature in a high-speed mixer and mixed under vacuum for about 1 minute to form a dispersion. The block copolymer and antioxidant were combined at room temperature and added to a Sigma Blade Mixer preheated to an oil heater setting of 185°C. The mixture was then heated and mixed under a nitrogen blanket to a temperature sufficient to melt the components (i.e., 150°C-190°C) to form a molten composition. Next, about one-third of the tackifier and components with relatively low melting temperatures were added to the molten block copolymer composition and mixed until homogeneous. This process was repeated until all components were added and the mixture was homogeneous. Subsequently, the dispersion was added to the molten composition and the composition was mixed at a temperature of 150°C-190°C to form an adhesive composition. The amounts of components in each composition shown in Tables 1, 2, and 3 are in mass percent.

[0095] Next, the hot-melt pressure-sensitive adhesive compositions obtained in Examples 1 to 5 were tested according to viscosity, flammability I and II test methods, loop tack test method, 180-degree peel test method, and SAFT test method (if specified). Viscosity was measured at 20 revolutions per minute. The results are shown in Tables 1 to 3 below.

[0096] The compositions of Examples 4 and 5 were further tested according to A) the 180-degree peel test method, excluding 1) the first film being polyethylene terephthalate (PET) and the second substrate being stainless steel (SS), and 2) the first film being PET and the second substrate being a mica sheet, as shown in Table 3, and B) the 90-degree peel test method, excluding the first sheet being a mica sheet and the second substrate being polyurethane foam.

[0097] [Table 1]

[0098] PLASTOLYN 290 = Aromatic hydrocarbon resin (Synthomer PLC, London, United Kingdom) SOLPRENE 1205 = Linear Random Styrene-Butadiene Block Copolymer 30% Styrene (Dynasol Group, Houston, Texas) VECTOR 4211A = Styrene-isoprene-styrene block copolymer (Taiwan Synthetic Rubber Corporation, Taipei City, Taiwan) CALSOL 5550 = Naphthenic oil (Calumet Specialty Products Partners, LP, Indianapolis, Indiana) ESCOREZ 5600 = Aromatically modified cyclic aliphatic hydrocarbon resin with a softening point of 100°C to 106°C (ExxonMobil Corporation) SOLPRENE 411 = 70 / 30 butadiene / styrene thermoplastic radial copolymer (Dynasol Group, Houston, Texas) KRATON D1124 = Branched styrene-isoprene copolymer with 30% polystyrene content (Kraton Corporation, Houston, Texas) FINAPRENE 401 = 22% radial / 78% styrene-butadiene block copolymer (Petrochemicals USA, Houston, Texas) ESCOREZ 5400 = Cycloaliphatic hydrocarbon resin (ExxonMobil Chemical, Houston, Texas) ENDEX 160 HC = Aromatic hydrocarbon resin with a ring-and-ball softening point of 159°C (Synthomer PLC, London, United Kingdom) IRGANOX 1076 = Antioxidant IRGANOX 1010 = Antioxidant PHOSGARD 200 == A tetrakis(2,6-dimethylphenyl)-m-phenylenebisphosphate flame retardant that is solid at room temperature and has a melting point of 95°C. PHOSGARD 300 = Polyphosphate Flame Retardant System (St. Louis Group LLC, Indianapolis, Indiana) PHOSGARD 700 = Polyphosphate and Nitrogen Flame Retardant System (St. Louis Group LLC) PHOSGARDAPP-HP = Ammonium polyphosphate flame retardant (St. Louis Group LLC) EXOLIT OP 945 = Diethylaluminum phosphinate microparticle powder (Clariant Plastics & Coatings, Germany) FIREBRAKE ZB = Zinc borate (Boron, Borax Inc., USA, California)

[0099] [Table 2]

[0100] SYLVAREZ TRM1115 = Polyterpene resin (Kraton Corporation) KAYDOL = mineral oil (Sonneborn, Petrolia, Pennsylvania) KRATON D1117 = Linear styrene-isoprene-styrene block copolymer 17% polystyrene (Kraton Corporation) CHARFLAM400D = 1,3,5-triazine-2,4,6(1H,3H,5H)-trione and 1,3,5-triazine-2,4,6-triamine in a 1:1 ratio (The St. Louis Group LLC)

[0101] [Table 3A]

[0102] [Table 3B]

[0103] EXOLIT OP 1311 = Phosphate Flame Retardant System (Clariant Plastics & Coatings) EXOLIT OP 935 = Phosphate Sodium Microparticle Powder (Clariant Plastics & Coatings) VECTOR 4411A = Linear styrene-isoprene-styrene block copolymer, Dexco Polymers, TSRC Corporation (Taiwan) CALPRENE 401 = Styrene-butadiene-styrene block copolymer (Dynasol Group, Houston, Texas) KRATON D1124 = Styrene-isoprene radial block copolymer (Kraton Corp., Houston, Texas) TAIPOL 7126 = Maleic anhydride-modified styrene-ethylene / butylene / styrene linear triblock copolymer, manufactured by TSRC Corporation (Taiwan) SYLVALITE RE100L = Rosin ester (Kraton Corp.) CHARFLAM 400 = Expanding flame retardant (St. Louis Group LLC, (Indianapolis, Indiana)) 1 = The samples were tested according to the 180-degree peel test method, except that the first substrate was polyethylene terephthalate (PET) and the second substrate was stainless steel (SS). 2 = The samples were tested according to the 180-degree peel test method, except that the first substrate was polyethylene terephthalate (PET) and the second substrate was a mica sheet. 3 = The samples were tested according to the 90-degree peel test method, except that the first substrate was a mica sheet (MICA) and the second substrate was a polyurethane foam pad.

[0104] Other embodiments are within the scope of the claims. Documents referenced herein by reference are incorporated to the extent that they do not contradict each other.

[0105] 1. A flame-retardant hot-melt pressure-sensitive adhesive composition comprising a styrene-based block copolymer, a tackifier, a phosphinate, and a polyphosphate, which passes the flammability test method I and the flammability test method II.

[0106] 2. A flame-retardant hot-melt pressure-sensitive adhesive composition comprising a styrene-based block copolymer, a tackifier, a phosphinate, and a polyphosphate, wherein the hot-melt pressure-sensitive adhesive composition exhibits a viscosity of 20,000 centipoise or less at 177°C.

[0107] 3. The flame-retardant hot-melt pressure-sensitive adhesive composition according to item 1 or 2, further comprising a plasticizer.

[0108] 4. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the polyphosphate comprises a polyphosphate having a melting point of 120°C or less.

[0109] 5. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the polyphosphate comprises a first polyphosphate and a second polyphosphate different from the first polyphosphate, and the second polyphosphate has a melting point of 120°C or less.

[0110] 6. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the phosphinate comprises an organic phosphinate.

[0111] 7. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the phosphinate comprises diethylphosphinate.

[0112] 8. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 7, further comprising a swelling agent, wherein the swelling agent is different from a polyphosphate.

[0113] 9. The flame-retardant hot-melt pressure-sensitive adhesive composition according to item 8, wherein the polyphosphate comprises ammonium polyphosphate and the foaming agent comprises a melamine-derived leavening agent.

[0114] 10. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 9, further comprising a component selected from the group consisting of metal oxides, carbon black, and combinations thereof.

[0115] 11. The flame-retardant hot-melt pressure-sensitive adhesive composition according to item 10, wherein the components are selected from the group consisting of aluminum trihydrate, magnesium hydroxide, titanium dioxide, zinc borate, carbon black, and combinations thereof.

[0116] 12. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 11, wherein the styrene-based block copolymer comprises a radial styrene-based block copolymer.

[0117] 13. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 12, comprising 5% to 35% by mass of a styrene-based block copolymer, 5% to 40% by mass of a phosphinate, 3% to 40% by mass of a polyphosphate, and 10% to 65% by mass of a tackifier.

[0118] 14. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 3 to 12, comprising 10% to 30% by mass of a styrene-based block copolymer, 5% to 30% by mass of a phosphinate, 5% to 30% by mass of a polyphosphate, 10% to 65% by mass of a tackifier, and 5% to 30% by mass of a plasticizer.

[0119] 15. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 8 to 12, comprising 10% to 30% by mass of a styrene-based block copolymer, wherein the styrene-based block copolymer comprises a radial block copolymer, 5% to 30% by mass of a phosphinate, 5% to 30% by mass of a polyphosphate, a leavening agent different from the polyphosphate, 10% to 65% by mass of a tackifier, and 5% to 30% by mass of a plasticizer.

[0120] 16. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 3 to 12, comprising 10% to 30% by mass of a styrene-based block copolymer, wherein the styrene-based block copolymer comprises a radial block copolymer, 5% to 30% by mass of a phosphinate, 5% to 30% by mass of a polyphosphate, a different swelling agent than the polyphosphate, 10% to 65% by mass of a tackifier, 5% to 30% by mass of a plasticizer, and a flame retardant selected from the group consisting of metal oxides, carbon black, and combinations thereof.

[0121] 17. The flame-retardant hot-melt pressure-sensitive adhesive composition according to item 16, wherein the polyphosphate comprises a first polyphosphate and a second polyphosphate different from the first polyphosphate, the second polyphosphate having a melting point of 120°C or less, and the swelling agent being different from both the first and second polyphosphates.

[0122] 18. The flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 17, wherein the sum of the mass of the phosphinate and the mass of the polyphosphate is 40% by mass or less relative to the mass of the flame-retardant hot-melt pressure-sensitive adhesive composition.

[0123] 19. The flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 17, wherein the sum of the mass of the phosphinate and the mass of the polyphosphate is 30% by mass or less relative to the mass of the flame-retardant hot-melt pressure-sensitive adhesive composition.

[0124] 20. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of items 1 to 19, which exhibits a peel force of at least 1.16 N / cm when tested according to the 180-degree peel adhesion test method.

[0125] 21. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of items 1 to 20, which exhibits a maximum delamination force of at least 2.94 N when tested according to the loop tack test method.

[0126] 22. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 21, having a shear bond failure temperature of at least 50°C.

[0127] 23. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of items 2 to 22, which passes the flammability test method I.

[0128] 24. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of items 2 to 23, which passes the flammability test method II.

[0129] 25. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of items 2 to 24, which passes the flammability test method I and the flammability test method II.

[0130] 26. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of items 1 to 25, exhibiting a viscosity of 8000 cP or less at 177°C.

[0131] 27. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 26, further comprising a component selected from the group consisting of metal oxides, carbon black, expansive graphite, and combinations thereof.

[0132] 28. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 27, wherein the components are selected from the group consisting of aluminum trihydrate, magnesium hydroxide, titanium dioxide, zinc borate, carbon black, expansive graphite, and combinations thereof.

[0133] 29. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 28, wherein the styrene-based block copolymer comprises a radial styrene-based block copolymer, a maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer, or a combination thereof.

[0134] 30. A method for applying a flame-retardant hot-melt pressure-sensitive adhesive composition onto a battery cell, comprising the steps of: discharging the flame-retardant hot-melt pressure-sensitive adhesive composition described in any one of items 1 to 29 from an application head in the form of a spray; and forming an adhesive coating surface on the surface of a first battery cell, wherein the forming step includes bringing the surface of the battery cell into contact with the spray of the flame-retardant hot-melt pressure-sensitive adhesive composition without the application head contacting the surface of the battery cell.

[0135] 31. The method according to item 27, further comprising the step of bringing the adhesive coating surface of the first battery cell into contact with the adhesive coating surface of the second battery to bond the first battery to the second battery cell.

[0136] 32. The method according to item 30 or 31, further comprising the step of bringing the adhesive coating surface of the first battery cell into contact with the outer surface of the second battery cell to bond the first battery cell to the second battery cell.

[0137] 33. The method according to any one of claims 30 to 32, wherein the first battery cell comprises a pouch made of a multilayer film including a first outer film layer, the first outer film layer comprising nylon, polyethylene terephthalate, or polypropylene, and a spray of an adhesive composition comes into contact with the first outer film layer.

[0138] 34. The method according to any one of claims 30 to 33, wherein the spray of the adhesive composition is in a form selected from the group consisting of fibrous, foamy, helical, and combinations thereof.

[0139] 35. A battery cell array comprising a first battery cell, a second battery cell, and a flame-retardant pressure-sensitive hot-melt adhesive composition according to any one of items 1 to 29, wherein the first battery cell is bonded to the second battery cell via the flame-retardant pressure-sensitive hot-melt adhesive composition.

Claims

1. 5% to 35% by mass of styrene-based block copolymer, 5% to 40% by mass of phosphinate, 3% to 40% by mass of polyphosphate, and 10% to 65% by mass of tackifier A flame-retardant hot-melt pressure-sensitive adhesive composition comprising a substance that passes the flammability test method I and the flammability test method II.

2. 5% to 35% by mass of styrene-based block copolymer, 5% to 40% by mass of phosphinate, 3% to 40% by mass of polyphosphate, and 10% to 65% by mass of tackifier A flame-retardant hot-melt pressure-sensitive adhesive composition comprising a substance, wherein the hot-melt pressure-sensitive adhesive composition exhibits a viscosity of 20,000 centipoise or less at 177°C.

3. The flame-retardant hot-melt pressure-sensitive adhesive composition according to claim 1 or 2, wherein the polyphosphate comprises a polyphosphate having a melting point of 120°C or lower.

4. The flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the polyphosphate comprises a first polyphosphate and a second polyphosphate different from the first polyphosphate, and the second polyphosphate has a melting point of 120°C or lower.

5. The flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the phosphinate comprises an organic phosphinate.

7. 10% to 30% by mass of styrene-based block copolymer, 5% to 30% by mass of phosphinate, 5% to 30% by mass of polyphosphate, and 10% to 65% by mass of tackifier Includes, A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 6, further comprising 5% to 30% by mass of a plasticizer.

8. A styrene-based block copolymer containing radial block copolymers, 10% to 30% by mass, 5% to 30% by mass of phosphinate, 5% to 30% by mass of polyphosphate, and 10% to 65% by mass of tackifier Includes, A plasticizer in an amount of 5% to 30% by mass, and A different leavening agent from the aforementioned polyphosphate A flame-retardant hot-melt pressure-sensitive adhesive composition according to claims 1 to 6, further comprising the above.

9. A styrene-based block copolymer containing radial block copolymers, 10% to 30% by mass, 5% to 30% by mass of phosphinate, 5% to 30% by mass of polyphosphate, and 10% to 65% by mass of tackifier Includes, 5% to 30% by mass of plasticizer, A leavening agent different from the aforementioned polyphosphate, and Flame retardants selected from the group consisting of metal oxides, carbon black, and combinations thereof. A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 6, further comprising:

10. The flame-retardant hot-melt pressure-sensitive adhesive composition according to claim 8 or 9, wherein the polyphosphate comprises ammonium polyphosphate and the leavening agent comprises a leavening agent derived from melamine.

11. The flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 10, wherein the sum of the mass of the phosphinate and the mass of the polyphosphate is 40% by mass or less relative to the mass of the flame-retardant hot-melt pressure-sensitive adhesive composition.

12. The flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 10, wherein the sum of the mass of the phosphinate and the mass of the polyphosphate is 30% by mass or less relative to the mass of the flame-retardant hot-melt pressure-sensitive adhesive composition.

13. When tested according to the 180-degree peel adhesion test method, a peel force of at least 1.16 N / cm was observed. When tested according to the loop tack test method, the maximum detachment force is at least 2.94 N. Shear bond failure temperature of at least 50°C, Viscosity of 8000 cP or less at 177℃, or combinations of these A flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 12, wherein the above is shown.

14. A method for applying a flame-retardant hot-melt pressure-sensitive adhesive composition to a battery cell, A step of dispensing a flame-retardant hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 13 from an application head in the form of a spray, A method for forming an adhesive coating surface on the surface of a first battery cell, wherein the forming step includes bringing the surface of the battery cell into contact with a spray of the flame-retardant hot-melt pressure-sensitive adhesive composition, without the application head touching the surface of the battery cell.

15. First battery cell, The second battery cell, and Flame-retardant pressure-sensitive hot melt adhesive composition according to any one of claims 1 to 14 A battery cell array comprising the first battery cell being bonded to the second battery cell via the flame-retardant pressure-sensitive hot-melt adhesive composition.

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