TWI726663B - Composite packaging material for lithium battery - Google Patents

Abstract

The present disclosure relates a composite packaging material for lithium battery. The composite packaging material for lithium battery sequentially comprises a protective layer, a polyurethane adhesive layer, an aluminum foil layer, a polyolefin adhesive layer and a heat sealant layer. Wherein, the dynamic damping factor (tanδ) of the polyurethane adhesive layer is in the range of 0.45 to 0.6. The polyurethane adhesive layer has suitable damping property such that the stress applied to the composite packaging material by the stamping equipment can be buffered and dissipated, so that the stamping property of the composite packaging material can be increased and the damage of the composite packaging material can be reduced during stamping process.

Description

Composite packaging materials for lithium batteries

The invention relates to a composite packaging material, in particular to a composite packaging material for lithium batteries.

Secondary lithium batteries are developing towards high volume energy density and are widely used in portable electronic products, smart phones and other fields. In recent years, along with the miniaturization and weight reduction of mobile devices, the outer packaging materials of the lithium secondary batteries carried are also required to be light and thin, and can be adapted to different sizes and thicknesses. Therefore, the old metal can packaging has been replaced by composite packaging materials with a thickness of 10 to 100 microns (μm) to produce so-called soft-packaged lithium batteries in order to reduce the weight of the batteries.

As a composite packaging material for lithium batteries, an aluminum-plastic film is generally obtained by bonding the protective layer/aluminum foil layer/heat-sealing layer with an adhesive. Each layer in the composite packaging material needs to have special physical and chemical properties. The protective layer must have good puncture resistance, abrasion resistance, and impact resistance to protect the internal film from scratches and reduce the shock and vibration caused by the battery due to falling. The aluminum foil layer must have good plasticity and gas barrier properties to provide plasticity during stamping and to prevent atmospheric gases such as moisture and oxygen from intruding into the battery. The heat-seal layer must have good heat-sealability and electrolyte resistance, so that the battery will not leak electrolyte during long-term use and storage, and it will not chemically react with the electrolyte.

When making soft packaging lithium batteries, the composite packaging material must first be stamped to form a recess. However, due to the different ductility of the protective layer and the aluminum foil layer, the protective layer with poor ductility and tensile strength cannot buffer the stress applied by the stamping equipment. Due to material fatigue, damage occurs between the protective layer and the aluminum foil layer, so the punchable depth of the composite packaging material is limited.

In the prior art, the mechanical properties are generally adjusted by changing the thickness of each layer in the composite packaging material, so as to reduce the stress damage of the composite packaging material and improve the stampability. However, in order to maintain the properties required as a battery packaging film, the thickness of each film layer has its use limit.

Therefore, there is still a need for a composite packaging material for lithium batteries that can increase the punching depth.

In view of the foregoing problems, one objective of the present invention is to provide a composite packaging material for lithium batteries, which sequentially includes a protective layer, a polyurethane adhesive layer, an aluminum foil layer, a polyolefin adhesive layer, and a heat seal layer, Wherein, the dynamic damping coefficient (tanδ) of the polyurethane adhesive layer is between 0.45 and 0.6. In the composite packaging material of the present invention, the polyurethane adhesive layer with the dynamic damping coefficient in the aforementioned range can provide good interlayer adhesion and stamping ductility, so that the composite packaging material can buffer and dissipate stress during stamping. Avoid fatigue damage of the protective layer due to stress concentration, thereby increasing the punchable depth of the concave portion of the composite packaging material.

In an embodiment of the present invention, the polyurethane adhesive layer includes a polyurethane adhesive and a multi-hindered phenol, and the use of the multi-hindered phenol per hundred parts by weight of the polyurethane adhesive The amount can be between 4 to 10 parts by weight.

In an embodiment of the present invention, the polyvalent hindered phenol includes a ternary hindered phenol or a quaternary hindered phenol.

In an embodiment of the present invention, the polyhydric hindered phenol may be selected from 1,3,5-tris(3,5-di-tertiarybutyl-4-hydroxybenzyl)-1,3,5-triazine -2,4,6-triketone, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tertiarybutyl-4hydroxybenzyl)benzene and tetrakis(3, At least one of the group consisting of 5-di-tertiary butyl hydroxyhydrocinnamic acid) neopentylerythritol ester or a combination thereof.

In an embodiment of the present invention, the polyurethane adhesive contains 85.7 to 90.9 parts by weight of polyester polyol and 10.1 to 14.3 parts by weight of polyisocyanate.

In an embodiment of the present invention, the thickness of the polyurethane adhesive layer may be between 2 and 10 microns (μm).

Another object of the present invention is to provide a composite packaging material for lithium batteries, which sequentially includes: a protective layer, a polyurethane adhesive layer, an aluminum foil layer, a polyolefin adhesive layer, and a heat seal layer, wherein the polyamine The formate adhesive layer contains a polyurethane adhesive and a multi-element hindered phenol, and the usage amount of the multi-element hindered phenol is between 4 to 10 parts by weight per hundred parts by weight of the aforementioned polyurethane adhesive between.

In another embodiment of the present invention, the polyhydric hindered phenol includes a trihydric phenol hindered phenol or a tetrahydric phenol hindered phenol.

In another embodiment of the present invention, the polyvalent hindered phenol may be selected from 1,3,5-tris (3,5-di-tertiary butyl-4-hydroxybenzyl)-1,3,5-tris Oxazine-2,4,6-trione, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tertiarybutyl-4hydroxybenzyl)benzene, and tetrakis(3 , At least one of the group consisting of, 5-di-tertiary butyl hydroxyhydrocinnamic acid) neopentylerythritol ester or a combination thereof.

In another embodiment of the present invention, the polyurethane adhesive includes 85.7 to 90.9 parts by weight of polyester polyol and 10.1 to 14.3 parts by weight of polyisocyanate.

In another embodiment of the present invention, the glass transition temperature (Tg) of the polyester polyol is between -10 and 30°C.

In another embodiment of the present invention, the polyester polyol is obtained by polymerizing a polyacid with a carboxyl group (COOH) and a polyol with a hydroxyl group (OH), and the number average molecular weight of the polyester polyol is between 8,000 and Between 30,000.

In another embodiment of the present invention, the polyisocyanate may be selected from trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butene Diisocyanate, 2,3-butene diisocyanate, 1,3-butene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene Diisocyanate, 2,6-diisocyanate methyl hexanoate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanate methyl-3,5,5-trimethyl Cyclohexyl isocyanate, 4,4'-methylene bis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,4-bis (Isocyanate methyl) cyclohexane, 1,3-bis(isocyanate methyl) cyclohexane, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate Isocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate or mixtures thereof, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, 4 ,4'-Diphenyl ether diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate or mixtures thereof, ω,ω'-diisocyanate-1,4-diethylbenzene , 1,3-bis(1-isocyanato-1-methylethyl)benzene, 1,4-bis(1-isocyanato-1-methylethyl)benzene or mixtures thereof, triphenyl Methane-4,4',4''-triisocyanate, benzene-1,3,5-triisocyanate, toluene-2,4,6-triisocyanate, 4,4'-diphenyldimethylmethane- 2,2',5,5'-tetraisocyanate, dimers, trimers, biurets, allophanates derived from the above-mentioned isocyanate monomers, and those obtained from carbon dioxide and the above-mentioned polyisocyanate monomers have 2, At least one of the group consisting of polyisocyanate of 4,6-oxadiazinetrione ring or a combination thereof.

In another embodiment of the present invention, the dynamic damping coefficient (tanδ) of the polyurethane adhesive layer is between 0.45 and 0.6.

The above content of the invention aims to provide a simplified summary of the content of the disclosure, so that readers have a basic understanding of the content of the disclosure. This summary is not a complete summary of the present disclosure, and its intention is not to point out important/key elements of the embodiments of the present invention or to define the scope of the present invention. After referring to the following embodiments, those with ordinary knowledge in the technical field to which the present invention belongs can easily understand the basic spirit of the present invention, as well as the technical means and implementation modes adopted by the present invention.

In order to make the description of the disclosure of the present invention more detailed and complete, the following provides an illustrative description for the implementation aspects and specific embodiments of the present invention; this is not the only way to implement or use the specific embodiments of the present invention. The embodiments disclosed below can be combined or substituted with each other under beneficial circumstances, and other embodiments can also be added to an embodiment without further description or description.

The advantages, features, and technical methods of the present invention will be described in more detail with reference to exemplary embodiments to make it easier to understand, and the present invention may be implemented in different forms, so it should not be understood to be limited to the embodiments set forth herein. On the contrary, for those with ordinary knowledge in the technical field, the provided embodiments will make this disclosure more thorough, comprehensive and complete to convey the scope of the present invention, and the present invention will only be covered by the scope of the appended patent application. definition.

Unless otherwise defined, all terms (including technical and scientific terms) and proper nouns used in the following text are essentially the same as those generally understood by those skilled in the art to which the present invention belongs, and for example, they are generally used Those terms defined in the dictionary should be understood as having the meaning consistent with the content of the related field, and unless they are clearly defined in the following text, they will not be understood in an overly idealized or overly formal meaning.

Furthermore, the so-called "dynamic damping factor (tanδ)" in this article refers to the ratio of the loss modulus (loss modulus) of the viscoelastic material to the storage modulus (storage modulus). "Damping effect" refers to the ability of an object to absorb mechanical energy and dissipate it internally when it is elastically deformed by an impact.

The following diagram illustrates the composite packaging material for lithium batteries of the present invention. As shown in Figure 1, the composite packaging material 100 for lithium batteries of the present invention includes a protective layer 10 and a polyurethane adhesive in sequence. The layer 20, the aluminum foil layer 30, the polyolefin adhesive layer 40 and the heat seal layer 50. The heat-seal layer is used as the inner layer of the battery package, forming a concave surface during the stamping process, and on the side containing battery materials such as electrolyte, and the protective layer is used as the outer layer, forming a convex surface during the stamping process, and being in contact with the external environment.

The protective layer 10 of the composite packaging material for lithium batteries of the present invention can be, for example, a polyamide film, and preferably a biaxially stretched polyamide film. The use of polyamide film as the protective layer 10 can have excellent flexibility, abrasion resistance, puncture resistance, heat resistance and insulation, etc., and can prevent the inner layer of the composite packaging material 100 from being scratched, and buffer the battery caused by the outside world. The shock and vibration of the battery protect the inside of the battery. Preferably, the thickness of the protective layer 10 may be between 15 and 40 microns (μm) to provide a sufficient protective effect.

The polyurethane adhesive layer 20 is used to adhere the protective layer 10 and the aluminum foil layer 30. In an embodiment of the present invention, the dynamic damping coefficient (tanδ) of the polyurethane adhesive layer 20 may be between 0.45 and 0.6. The polyurethane adhesive layer 20 with a dynamic damping coefficient in this range can match the protective layer 10 and the aluminum foil layer 30 and effectively buffer and dissipate the sudden stress on the composite packaging material when the stamping equipment is stamped, so as to reduce the composite packaging Material breakage during stamping and forming. The polyurethane adhesive layer 20 can tightly adhere the protective layer 10 made of organic material and the aluminum foil layer 30 made of metal material and can provide cushioning and stress-dissipating damping effects to avoid the gap between the protective layer 10 and the aluminum foil layer 30 during stamping. Cracks occur, thereby improving the punchability of the composite packaging material 100.

In an embodiment of the present invention, the polyurethane adhesive layer 20 may include a polyurethane adhesive and a polyvalent hindered phenol. Because the multi-hindered phenol can form hydrogen bonds with the nitrogen and oxygen atoms in the polyurethane adhesive through the phenolic hydroxyl group therein, when the polyurethane adhesive layer 20 is impacted, the hydrogen bonds therein can absorb the mechanical It can be converted into heat and energy dissipation by breaking the key, thereby effectively buffering and dissipating the sudden stress on the composite packaging material when the stamping equipment is stamping.

In an embodiment of the present invention, the usage amount of the multi-hindered phenol can be between 4 and 10 parts by weight per hundred parts by weight of the polyurethane adhesive. If the amount of multi-hindered phenol used is less than 4 parts by weight, the damping effect will be limited; if the amount of multi-hindered phenol used is more than 10 parts by weight, the multi-hindered phenol will create steric barriers between the molecular chains of polyurethane, thereby affecting hydrogen The production of the key reduces the damping effect.

Suitable multi-hindered phenols can have relatively high molecular weights and can exhibit non-volatile properties at high temperatures. Preferably, the suitable polyvalent hindered phenol may include a ternary hindered phenol with s-triazine or mesitylene as the skeleton, or a quaternary hindered phenol with neopentylerythritol as the skeleton. Suitable ternary hindered phenols can be, for example, but not limited to 1,3,5-tris(3,5-di-tertiarybutyl-4-hydroxybenzyl)-1,3,5-triazine-2,4 ,6-Triketone (molecular weight: 784.08) or 1,3,5-trimethyl-2,4,6-tris(3,5-di-tertiary butyl-4 hydroxybenzyl)benzene (molecular weight: 775.20 ). Suitable tetrahydric phenol hindered phenols can be, for example, but not limited to, tetrakis (3,5-di-tertiary butylhydroxyhydrocinnamic acid) neopentylerythritol ester (molecular weight: 1177.63). One of the above-mentioned polybasic hindered phenols may be used alone, or a mixture of two or more kinds may be used without particular limitation.

Since the dynamic damping coefficient is related to the thickness of the adhesive layer, in order to maintain a suitable dynamic damping coefficient, the thickness of the polyurethane adhesive layer 20 can be between 2 and 10 microns (µm), preferably between 2 and Between 7 microns (μm). If the thickness of the polyurethane adhesive layer 20 is less than 2 micrometers (μm), not only may the adhesive strength be insufficient, but also the damping effect will be insignificant. If the thickness of the polyurethane adhesive layer 20 is greater than 10 micrometers (μm), the adhesive strength may also decrease.

In an embodiment of the present invention, the polyurethane adhesive may include 85.7 to 90.9 parts by weight of polyester polyol and 10.1 to 14.3 parts by weight of polyisocyanate. If the usage amount of the polyester polyol is too low, the polyisocyanate will produce side reactions other than the polymerization of the polyester polyol, which will reduce the ductility and adhesion. If the amount of polyester polyol used is too high, the polymerization will not be complete and the adhesive strength will decrease.

The glass transition temperature (T _g ) of suitable polyester polyol can be between -10 and 30℃. When the glass transition temperature (T _g ) is lower than -10℃, it will affect the polyurethane adhesive layer. 20 punchability. When the glass transition temperature (T _g ) is higher than 30°C, it will affect the adhesive strength of polyurethane after polymerization and curing.

In an embodiment of the present invention, the number average molecular weight of the polyester polyol may be between 8,000 and 30,000, and preferably between 10,000 and 20,000. If the number-average molecular weight is less than 8,000, the glue that has not fully cured has insufficient cohesion. Therefore, after the laminated composite packaging material is rolled up, peeling phenomena such as interlayer sliding and swelling will occur. If the number average molecular weight is greater than 30,000, the viscosity of the polyester polyol will increase and its solubility in solvents will decrease. Therefore, the formulated glue will have poor fluidity and poor wettability to the substrate.

Suitable polyester polyols can be obtained, for example, by polymerization of polyacids having carboxyl groups (COOH) and polyols having hydroxyl groups (OH). Suitable polybasic acids can be, for example, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, phthalic acid, adipic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, trimellitic acid, Single compounds or mixtures of pyromellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, itaconic anhydride and these ester compounds, but not Limited to this. Suitable polyols can be, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-butanediol, 1,4 -Cyclohexanedimethanol, trimethylolpropane, glycerin, 1,9-nonanediol, 3-methyl-1,5-pentanediol, polyether polyol, polycarbonate polyol, polyolefin polyol A single compound or mixture of alcohol, acrylic polyol, polyurethane polyol, etc., but not limited thereto.

The polyisocyanate suitable for the polyurethane adhesive of the present invention can be, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2- Butene diisocyanate, 2,3-butene diisocyanate, 1,3-butene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene Aliphatic diisocyanates such as methyl diisocyanate, 2,6-diisocyanate methyl hexanoate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanate methyl-3, 5,5-Trimethylcyclohexylisocyanate, 4,4'-methylenebis(cyclohexylisocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexanedi Alicyclic diisocyanates such as isocyanate, 1,4-bis(isocyanatemethyl)cyclohexane, 1,3-bis(isocyanatemethyl)cyclohexane, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4' -Diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate or 2,6-toluene diisocyanate or mixtures thereof, 4,4' -Aromatic diisocyanates such as toluidine diisocyanate, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 1,3-xylene diisocyanate or 1,4-xylene diisocyanate or mixtures thereof, ω ,ω'-diisocyanato-1,4-diethylbenzene, 1,3-bis(1-isocyanato-1-methylethyl)benzene or 1,4-bis(1-iso Aromatic aliphatic diisocyanates such as cyano-1-methylethyl)benzene or mixtures thereof, triphenylmethane-4,4',4''-triisocyanate, benzene-1,3,5-triisocyanate, Organic triisocyanate such as toluene-2,4,6-triisocyanate, polyisocyanate monomer such as organic tetraisocyanate such as 4,4'-diphenyldimethylmethane-2,2',5,5'-tetraisocyanate, It can also be a dimer, trimer, biuret, allophanate derived from the above isocyanate monomer, and 2,4,6-oxadiazinetrione obtained from carbon dioxide and the above polyisocyanate monomer. Cyclic polyisocyanate or a combination of the foregoing materials, but not limited thereto.

Suitable polyisocyanates can also be polyisocyanates modified by polyols. The polyol used for upgrading can be, for example, ethylene glycol, propylene glycol, butylene glycol, hexanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-Dimethylolpropane, cyclohexanedimethanol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, neopentylerythritol, sorbitol, etc. The molecular weight is less than 200 The adduct of low-molecular-weight polyols, or with a molecular weight of 200 to 20,000 polyester polyols, polyether ester polyols, polyester amide polyols, polycaprolactone polyols, polyvalerolactone polyols, Acrylic polyols, polycarbonate polyols, polyhydroxyalkanes, castor oil, polyurethane polyols, and other adducts, etc., but are not limited to these.

When using the polyurethane adhesive layer 20 to adhere the protective layer 10 and the aluminum foil layer 30, the glue solution obtained by mixing polyester polyol, polyisocyanate and polyvalent hindered phenol is first coated on the surface of the aluminum foil layer 30, and then the protective layer After the layer 10 is bonded, it is aged. During the curing process, the hydroxyl group (OH) of the polyester polyol will react with the isocyanate group (NCO) of the polyisocyanate to polymerize into polyurethane, and then form an adhesive polyurethane layer. Participate in the polymerization reaction, but doped between the molecular chains of polyurethane, and form hydrogen bonds with polyurethane to produce a damping effect.

In addition, according to actual needs, an appropriate amount of additives can be added to the polyurethane adhesive to adjust the reactivity, coating operability or other required properties. These additives can be used by those who are well-known in this technical field. Special restrictions.

The aluminum foil layer 30 of the composite packaging material for lithium batteries of the present invention can be a soft aluminum foil made of pure aluminum or an aluminum foil containing 2wt% iron, so that the composite packaging material 100 has ductility and gas barrier properties. Preferably, the aluminum foil layer 30 may undergo chemical conversion treatment before bonding to oxidize the metal aluminum on the surface to form a dense oxide film, thereby improving the barrier properties to moisture and oxygen. The method of chemical conversion treatment may be, for example, coating a chemical conversion liquid on the surface of the aluminum foil layer 30 and baking at a high temperature of 80 to 180° C. to add polar functional groups on the surface of the aluminum foil layer 30.

In an embodiment of the present invention, the thickness of the aluminum foil layer 30 may be between 15 and 60 microns (μm). If the thickness of the aluminum foil layer 30 is less than 15 micrometers (μm), the aluminum foil layer 30 is prone to cracks or pinholes during stamping and forming, thereby affecting the gas barrier properties of the aluminum foil layer 30. If the thickness of the aluminum foil layer 30 is greater than 60 micrometers (μm), the total thickness of the packaging material will be thicker and the weight will increase.

The aluminum foil layer 30 and the heat sealing layer 50 are adhered through the polyolefin adhesive layer 40. The polyolefin adhesive layer 40 is preferably a polyolefin adhesive containing at least one of polyethylene and polypropylene. The thickness of the polyolefin adhesive layer 40 can be between 3 and 10 microns (μm) to provide good adhesion and electrolyte resistance. In the composite material for lithium battery packaging of the present invention, a well-known polyolefin adhesive applicable in this technical field can be selected to bond the aluminum foil layer 30 and the heat-sealing layer 50 without any particular limitation.

The heat-sealing layer 50 of the composite packaging material for lithium batteries of the present invention can be, for example, a polyolefin film, because the polyolefin film has good heat-sealability, electrolyte corrosion resistance, puncture resistance, and insulation. In an embodiment of the present invention, the heat-sealing layer 50 may be at least one thermoplastic resin film among polyethylene, polypropylene, and olefin-based copolymers. In a preferred embodiment of the present invention, the heat-sealing layer 50 may be a polypropylene film. The thickness of the heat-sealing layer 50 may be between 30 and 80 micrometers (μm) to provide sufficient heat-sealability and electrolyte resistance properties required as a battery packaging material.

The following examples are used to illustrate the composite packaging material for lithium batteries of the present invention, but the content of the present invention is not limited thereto.

Example 1

Preparation of polyurethane adhesive containing multiple hindered phenols

Take 88.89 grams of polyester polyol (TM-K55, purchased from Toyo Advanced Technology, Taiwan) and 11.11 grams of polyisocyanate (CAT-10, Toyo Advanced Technology, Taiwan) and mix them evenly, and then dilute them with ethyl acetate as a solvent. Polyurethane adhesive liquid with 15% solid content. Take 4 grams of 1,3,5-tris (3,5-di-tertiary butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6-trione (triazine Type hindered phenol, Evernox 3114, purchased from Miaochun Industrial, Taiwan) was mixed with ethyl acetate to prepare a 15% solid content multi-hindered phenol solution, and this multi-hindered phenol solution was added to the polyurethane adhesive liquid , After fully mixing, a polyurethane adhesive containing multi-element hindered phenol is obtained.

Preparation of polyolefin adhesive

Mix 100 grams of maleic anhydride modified polypropylene (XP11B, purchased from Mitsui Chemicals, Japan) and 5 grams of polyisocyanate hardener (N3390, purchased from COVESTRO, Germany), and use methylcyclohexane as a solvent to dilute It becomes a glue with a solid content of 15% to form a polyolefin adhesive.

Preparation of composite packaging materials

After coating 3 micrometers (μm) of the aforementioned polyurethane adhesive on the surface of a 40 micron (μm) chemically treated aluminum foil (model A8021-0, purchased from Dongyi Aluminum, South Korea), and the thickness A 25 micrometer (μm) polyamide film (RX-F, available from KOHJIN, Japan) was laminated, and then dried at 85°C for 1.5 minutes. Then, 5 micrometers (μm) of the aforementioned polyolefin adhesive was coated on the other surface of the aluminum foil, and a cast polypropylene film (ET20, purchased from Okamoto Co., Ltd., Japan) with a thickness of 40 micrometers (μm) was laminated. Dry for 1.5 minutes at 120°C. After the laminated film was allowed to stand and mature for 7 days, a composite packaging material for lithium batteries was obtained.

Example 2

The composite packaging material was prepared in the same manner as in Example 1, but the usage amount of the multi-hindered phenol was changed to 7 grams.

Example 3

The composite packaging material was prepared in the same manner as in Example 1, but the usage amount of the multi-hindered phenol was changed to 10 grams.

Comparative example 1

The composite packaging material was prepared in the same manner as in Example 1, but without adding a multi-component hindered phenol to the polyurethane adhesive layer.

Comparative example 2

The composite packaging material was prepared in the same manner as in Example 1, but the usage amount of the multi-hindered phenol was changed to 12 grams.

Hereinafter, the composite packaging material proposed by the present invention is evaluated and measured according to the following methods, and the measurement results are shown in Table 1 below.

Dynamic damping coefficient of polyurethane adhesive layer (tanδ)

The polyurethane adhesives prepared in the examples and comparative examples were poured into a flat-bottomed box covered with a release film, and heated in an oven at 80° C. until no solvent remained and an adhesive layer with a thickness of about 2 mm was formed. Place the dried adhesive layer in an oven at 45°C for 7 days.

Cut the matured adhesive layer into 30±2mm×3±1mm×2±0.5mm, and measure the elastic modulus of the adhesive layer through a dynamic mechanical analyzer (Q800, purchased from TA Instruments, USA) at 30°C (G′) and viscous modulus (G″), and then calculate the dynamic damping coefficient (tanδ) from the following formula 1. The measurement method is a single cantilever test, the heating rate is 2℃/min, and the test frequency is 1Hz. G′/G″ = tanδ (Equation 1)

Adhesion strength between polyamide film and aluminum foil

The adhesive strength between the polyamide film and the aluminum foil of the composite packaging materials prepared in Examples 1 to 3 and Comparative Examples 1 to 2 was measured. The method of measuring the adhesion strength is to follow the ASTM D-1876 specification, and perform a T-peel test with a 15mm wide test piece.

Punching result

The composite packaging materials prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to a punching test at a punching speed of 3000 μm/sec, and the punching area was 200×100 mm. Each punching depth was tested 5 times, and the appearance after each punching and forming was observed for damage. Table 1 Measurement results of Examples 1-3 and Comparative Examples 1-2 Example 1 Example 2 Example 3 Comparative example 1 Comparative example 2 30℃ elastic modulus G′ (MPa) 15 16 twenty four 26 17 30℃ viscosity modulus G″ (MPa) 6.8 9.6 13.2 9.9 6.3 tanδ 0.45 0.6 0.55 0.38 0.37 Adhesion strength (N/15mm) 3.67 3.92 3.71 3.82 3.07 Punching depth (7.5mm) 5Pass/5 5Pass/5 5Pass/5 3Pass/5 2Pass/5 Punching depth (8.0mm) 5Pass/5 5Pass/5 5Pass/5 0Pass/5 0Pass/5 Punching depth (8.5mm) 3Pass/5 5Pass/5 4Pass/5 - - Note: "-" means not tested.

Compared with the comparative example, the punching depth of the composite packaging materials of Examples 1 to 3 is increased by at least 1.0mm. It can be seen that when the polyurethane adhesive layer has a specific range of dynamic damping coefficient, it can play a buffering effect and increase The punchability of the composite packaging material reduces the damage caused by the punching process. Moreover, the polyurethane adhesive layer in the composite packaging materials of Examples 1 to 3 can still maintain a good adhesive strength between the aluminum foil layer and the protective layer.

The composite packaging material of the present invention produces a damping effect by adding a multi-element hindered phenol to the polyurethane coating layer to make the hydrogen bond between the multi-element hindered phenol and the polyurethane produce a damping effect. The packaging material can effectively buffer and dissipate the stress applied to the composite packaging material during stamping and forming, so the stamping formability of the composite packaging material can be improved, and the damage caused by stamping can be reduced, and the composite packaging material can still be maintained as a battery packaging film The required characteristics.

Although the present invention has been disclosed in several preferred embodiments as above, it is not intended to limit the present invention. Anyone with ordinary knowledge in the art can make any changes without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of the attached patent application.

10: Protective layer 20: Polyurethane adhesive layer 30: Aluminum foil layer 40: Polyolefin adhesive layer 50: Heat seal layer 100: Composite packaging materials

Figure 1 is a schematic structural view of a composite packaging material for lithium batteries according to an embodiment of the present invention.

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10: Protective layer 20: Polyurethane adhesive layer 30: Aluminum foil layer 40: Polyolefin adhesive layer 50: Heat seal layer 100: Composite packaging materials

Claims (13)

A composite packaging material for lithium batteries, which sequentially comprises: a protective layer, a polyurethane adhesive layer, an aluminum foil layer, a polyolefin adhesive layer and a heat-sealing layer; wherein, the polyurethane The dynamic damping coefficient (tanδ) of the ester adhesive layer is between 0.45 and 0.6. The polyurethane adhesive layer contains a polyurethane adhesive and a multi-element hindered phenol, and is relative to each hundred parts by weight. For the polyurethane adhesive, the usage amount of the multi-hindered phenol is between 4 and 10 parts by weight. The composite packaging material for lithium batteries according to claim 1, wherein the multi-element hindered phenol comprises a ternary hindered phenol or a quaternary hindered phenol. The composite packaging material for lithium batteries according to claim 1, wherein the polyvalent hindered phenol is selected from 1,3,5-tris(3,5-di-tertiarybutyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6-trione, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tertiary butyl-4 hydroxy At least one of the group consisting of benzyl)benzene and tetrakis (3,5-di-tertiary butyl hydroxyhydrocinnamic acid) neopentylerythritol ester or a combination thereof. The composite packaging material for lithium batteries according to claim 1, wherein the polyurethane adhesive contains 85.7 to 90.9 parts by weight of a polyester polyol and 10.1 to 14.3 parts by weight of a polyisocyanate. The composite packaging material for lithium batteries according to claim 1, wherein the thickness of the polyurethane adhesive layer is between 2 and 10 microns (μm). A composite packaging material for lithium batteries, which sequentially comprises: a protective layer, a polyurethane adhesive layer, an aluminum foil layer, a polyolefin adhesive layer and a heat-sealing layer; wherein, the polyurethane The ester adhesive layer contains a polyurethane adhesive and a multi-element hindered phenol, and the amount of the multi-element hindered phenol is between 4 to 10 weight per hundred parts by weight of the polyurethane adhesive Between copies. The composite packaging material for lithium batteries according to claim 6, wherein the multi-element hindered phenol comprises a trivalent phenol hindered phenol or a quaternary phenol hindered phenol. The composite packaging material for lithium batteries according to claim 6, wherein the multi-element hindered phenol is selected from 1,3,5-tris(3,5-di-tertiarybutyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6-trione, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tertiary butyl-4 hydroxy At least one of the group consisting of benzyl)benzene and tetrakis (3,5-di-tertiary butyl hydroxyhydrocinnamic acid) neopentylerythritol ester or a combination thereof. The composite packaging material for lithium batteries according to claim 6, wherein the polyurethane adhesive contains 85.7 to 90.9 parts by weight of a polyester polyol and 10.1 to 14.3 parts by weight of a polyisocyanate. The composite packaging material for lithium batteries according to claim 9, wherein the glass transition temperature (Tg) of the polyester polyol is between -10 and 30°C. The composite packaging material for lithium batteries according to claim 9, wherein the polyester polyol is obtained by polymerizing a polyacid having a carboxyl group (COOH) and a polyol having a hydroxyl group (OH), and the polyester polyol The number average molecular weight of the alcohol is between 8,000 and 30,000. The composite packaging material for lithium batteries according to claim 9, wherein the polyisocyanate is selected from trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate Isocyanate, 1,2-butene diisocyanate, 2,3-butene diisocyanate, 1,3-butene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4 -Trimethylhexamethylene diisocyanate, 2,6-diisocyanate methylhexanoate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanate methyl-3 ,5,5-Trimethylcyclohexyl isocyanate, 4,4'-methylene bis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane Diisocyanate, 1,4-bis(isocyanatemethyl)cyclohexane, 1,3-bis(isocyanatemethyl)cyclohexane, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate Isocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate or mixtures thereof, 4,4'-toluidine diisocyanate , Dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate or mixtures thereof, ω,ω'-diisocyanate- 1,4-Diethylbenzene, 1,3-bis(1-isocyanato-1-methylethyl)benzene, 1,4-bis(1-isocyanato-1-methylethyl) ) Benzene or its mixture, triphenylmethane-4,4',4"-triisocyanate, benzene-1,3,5-triisocyanate, toluene-2,4,6-triisocyanate, 4,4'-di Phenyldimethylmethane-2,2',5,5'-tetraisocyanate, dimer, trimer, biuret, allophanate and polyisocyanate derived from the above isocyanate monomer Cyanide At least one or a combination of polyisocyanates with 2,4,6-oxadiazinetrione ring obtained from acid ester monomers. The composite packaging material for lithium batteries according to claim 8, wherein the dynamic damping coefficient (tanδ) of the polyurethane adhesive layer is between 0.45 and 0.6.

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