JP6834267B2 - Sheet for drawing - Google Patents

Description

The present invention relates to a drawing sheet. This sheet can be draw-molded and suitably used as an exterior material for a lithium ion battery.

The sheet used as the exterior material of the lithium ion battery is generally a laminated sheet having a multi-layer structure in which a plastic sheet, an aluminum foil, a sealant layer, etc. are laminated, and the wound-shaped or single-wafered laminated sheet may be used. It is stored, transported, and supplied in a stacked form. In any case, in these forms, one surface of the laminated sheet is in contact with the other surface of the adjacent laminated sheet.

Then, the laminated sheet can be drawn and molded to form the exterior material, and the battery element can be accommodated in the accommodating portion (recess) and then sealed to manufacture a lithium ion battery. On the outer surface of the manufactured battery, a printed image showing the manufacturer, production lot, serial number, etc. of the battery and a printed image such as a barcode are printed. In addition, this printing is usually performed by an inkjet printing method using an ink containing a volatile solvent (for example, methyl ethyl ketone).

By the way, in the step of drawing and molding the laminated sheet, since the laminated sheet is stretched along the molding die, it is necessary to sufficiently reduce the friction between the two. Therefore, in order to reduce the coefficient of friction of the outer surface of this laminated sheet, various measures have been conventionally taken.

For example, Patent Document 1 discloses a technique for reducing the dynamic friction coefficient of a laminated sheet by applying silicone oil to the outer surface of the laminated sheet to form a film thereof. Further, Patent Documents 2 and 3 disclose a technique for applying a slip agent to improve slipperiness.

JP-A-2002-56824 Japanese Unexamined Patent Publication No. 2002-216713 Japanese Unexamined Patent Publication No. 2002-216714

However, in order to obtain sufficient draw forming suitability in the technique of applying silicone oil to the outer surface of the laminated sheet to reduce the coefficient of dynamic friction, a large amount of silicone oil must be applied. When a large amount of silicone oil is applied in this way, the suitability for inkjet printing is lost, and the printed image cannot be printed.

Further, even in the technique of applying a slip agent to improve the slipperiness, a large amount of the slip agent must be applied in order to obtain sufficient draw forming suitability. Since the slip agent has a bleeding property, it is applied to the outer surface of the laminated sheet, for example, when the laminated sheet is stored and transported in a wound form, or when a single-wafer-shaped laminated sheet is stacked and stored and transported. The slip agent bleeds to the surface (inner surface) on the opposite side of the adjacent laminated sheet and migrates. The inner surface contaminated with the slip agent thus constitutes the inner surface of the lithium ion battery and comes into contact with the battery element, which affects the battery performance.

Therefore, the present invention is a draw forming sheet that enhances slipperiness with a molding die to improve draw molding suitability, has print suitability, and does not contaminate the opposite surface (inner surface). The purpose is to provide.

That is, the invention according to claim 1 is a draw molding sheet in which silicone oil and a slip agent other than silicone oil are applied in this order on one side of a base sheet having draw molding suitability.
The silicone oil is made from fatty acid ester-modified silicone oil or polyether-modified silicone oil, the coating weight of 0.15~3.00mg / ^{m 2,}
The coating amount of the slip agent other than silicone oil 3.0~10.0mg / ^{m 2} der Ri
,
It is a draw forming sheet characterized in that the silicone oil is composed of a single component silicone oil or a mixture of two or more components and has a refractive index of 1.40 to 1.436.

The invention according to claim 2 is the draw forming sheet according to claim 1 , wherein the slip agent is a fatty acid amide.

The invention described in Claim 3 is a shaped sheet diaphragm of claim 2, wherein said fatty acid amide is an unsaturated fatty acid amide.

The invention according to claim 4 is the draw-forming sheet according to claim 3 , wherein the unsaturated fatty acid amide is erucic acid amide or oleic acid amide.

The drawing-forming sheet according to any one of claims 1 to 4, wherein the invention according to claim 5 is a sheet for the exterior of a lithium ion battery.

In the draw forming sheet of the present invention, since silicone oil and a slip agent are applied to one side of the base sheet in this order, the coefficient of static friction on the outer surface thereof becomes small, and it can be used as a molding die during draw forming. It can be sufficiently stretched and molded along.

Moreover, since both the silicone oil and the slip agent are in appropriate amounts and a large amount of silicone oil or a large amount of slip agent is not applied, the ink jet printing is not hindered, and the slip agent is opposite. It does not migrate to the side surface and contaminate it.

It is sectional drawing which shows the example of the sheet for drawing forming which concerns on this invention. It is sectional drawing which shows the 2nd example of the draw forming sheet which concerns on this invention. It is sectional drawing which shows the 3rd example of the sheet for draw forming which concerns on this invention.

Hereinafter, the present invention will be described by taking as an example a sheet for the exterior of a lithium ion battery as a sheet for drawing. As described above, this exterior sheet can be drawn and molded to accommodate the battery element in the accommodating portion (recess), and then sealed to manufacture a lithium ion battery. After that, it is possible to print on the outer surface of the ink by an inkjet printing method using an ink containing a volatile solvent (for example, methyl ethyl ketone).

FIG. 1 is a cross-sectional view showing an example of a draw forming sheet 1 according to the present invention. This sheet 1
It is configured to have a two-layer coating film on one side of a base sheet having a multi-layer structure. The base material sheet has a multi-layer structure, and the plastic sheet 11, the aluminum foil layer 13 provided with the corrosion prevention treatment layer 13a on at least one side, and the sealant layer 15 are laminated via the adhesive layers 12 and 14, respectively. It is composed of. The coating films 1a and 1b are applied to the outer surface of the plastic sheet 11. Of the two layers of the coating films 1a and 1b, the coating film 1a closer to the plastic sheet 11 is a coating film of silicone oil. Further, the coating film 1b on the far side is a coating film of a slip agent, and the coating film 1b is overlaid on the coating film 1a so as to be in contact with the coating film 1a. The coating film 1b may be provided scattered in a fine island shape.

The coating film 1a of the silicone oil needs to be composed of a higher fatty acid ester-modified silicone oil or a polyether-modified silicone oil. As can be seen from the experimental examples described later, when the coating film 1a is composed of another type of silicone oil, for example, dimethyl silicone oil, the printability for inkjet printing is insufficient.

Further, this silicone oil may be composed of a single component silicone oil or a mixed silicone oil in which two or more components of silicone oil are mixed, but the refractive index thereof is 1 as a whole. It is desirable that it is in the range of .40 to 1.45. The refractive index of the modified silicone oil reflects the ratio of substituents (higher fatty acid ester group or polyether group) contained in the modified silicone oil, and the larger the ratio of the substituents, the higher the refractive index. When a straight dimethyl silicone oil containing no substituent is used, the printability becomes insufficient as described above, but when the ratio of the substituent is excessive and therefore the refractive index is excessively large, the printability becomes insufficient. , The range of the coating amount that satisfies the printability, that is, the coating amount margin is narrowed. As can be seen from the experimental examples described later, when a higher fatty acid ester-modified silicone oil (SR-3) having a refractive index of 1.425 is used, the printability is in the range of ^{0.15 to 3.00 mg / m 2.} However, when a polyether-modified silicone oil (SR-2) having a refractive index of 1.403 was used, the printability was in the range of ^{0.15 to 1.20 mg / m 2.} A remarkable improvement effect is observed, and a sufficient improvement effect is not observed at a coating amount of 3.00 mg / m ^2. Further, when a polyether-modified silicone oil (SR-4) having a refractive index of 1.45 was used, a remarkable improvement effect on printability was observed in the range of a ^{coating amount of 1.20 to 3.00 mg / m 2.} , A sufficient improvement effect is not seen at a coating amount of 0.15 mg / m ^2. Further, when a polyether-modified silicone oil (SR-5) having a refractive index of 1.436 is used, a sufficient effect of improving printability is not observed regardless of the coating amount. As described above, when the modified silicone oil having a refractive index in the range of 1.42 to 1.43 is used, the coating amount margin is the widest, and the refractive index is smaller or larger than this. , The coating amount margin becomes narrow.

Both of these higher fatty acid ester-modified silicone oils and polyether-modified silicone oils are commercially available from, for example, Momentive Performance Materials Japan and Shin-Etsu Chemical. These modified silicone oils are dispersed in a solvent such as isopropyl alcohol to form a coating liquid, and the coating liquid can be applied to form a coating film 1a. As the coating method, a spray coating method, a die coating method, a spin coating method, a dip coating method, a roll coating method, a bar coating method, a screen printing method, a gravure coating method and the like can be used.

Next, as the slip agent, a fatty acid amide such as an unsaturated fatty acid amide can be used. For example, erucic acid amide or oleic acid amide. Above all, erucic acid amide can be preferably used.

The application amount of the slip agent coating film 1b needs to be ^{3.0 to 10.0 mg / m 2.} If it is less than this, the coefficient of static friction is large and the draw forming suitability is insufficient. If the amount is more than this, the slip agent is transferred to the opposite surface (inner surface) of the adjacent drawing sheet 1 and contaminated during storage and transportation of the drawing sheet 1. This slip agent can also be applied in the same manner as the above-mentioned modified silicone oil. That is, the slip agent is dispersed in a solvent to form a coating liquid, and the coating liquid can be applied to form the coating film 1b. As a coating method, a spray coating method, a die coating method, a spin coating method, a dip coating method, a roll coating method, a bar coating method, a screen printing method, a gravure coating method and the like can be used.

In this example, the aluminum foil layer 13 and the sealant layer 15 are adhered to each other via the adhesive layer 14, but the adhesive layer 14 may be replaced with an adhesive resin. FIG. 2 is a cross-sectional view showing an example of a draw forming sheet 1'in which the aluminum foil layer 13 and the sealant layer 15 are adhered to each other by the adhesive resin 14'.

Further, in these examples, the plastic sheet 11 and the aluminum foil layer 13 are bonded to each other via the adhesive layer 12, but the surface of the aluminum foil layer 13 may be subjected to a base treatment prior to this bonding. .. FIG. 3 is a cross-sectional view showing an example of a draw forming sheet 1 ”in which the base treatment layer 13b is provided on the surface of the aluminum foil layer 13 and then the plastic sheet 11 is adhered via the adhesive layer 12. ..

Next, among the materials used in the first to third examples, the materials constituting the base sheet will be sequentially described. Next, a method for manufacturing the draw forming sheet 1, 1', 1 "according to the present invention will be described, and finally, a method for using the draw forming sheet 1, 1', 1" will be described.

(Plastic sheet 11)
The plastic sheet 11 plays a role of imparting heat resistance in the heat sealing process in manufacturing a lithium ion battery, suppressing the occurrence of pinholes that may occur in molding processing and distribution, and the like. In particular, in the case of an exterior material for a lithium ion battery for large-scale applications, scratch resistance, chemical resistance, insulation and the like can be imparted.

As the plastic sheet 11, a resin film formed of an insulating resin is preferable. Examples of the resin film include stretched or unstretched films such as polyester film, polyamide film and polypropylene film.

The plastic sheet 11 may be composed of a single-layer film, or may have a multilayer structure in which a plurality of films are laminated. Examples of these films include stretched or unstretched polyamide films, stretched or unstretched polyester films, and two-layer films of stretched polyamide films and stretched polyester films.

The thickness of the plastic sheet 11 is preferably 6 μm or more, more preferably 10 μm or more, in terms of improving moldability, heat resistance, pinhole resistance, and insulating property. Further, in terms of thinning and high heat dissipation, 60 μm or less is preferable, and 45 μm or less is more preferable. When the plastic sheet 11 is a film having a multilayer structure, the thickness is the total thickness thereof.

(Aluminum foil layer 13)
As the aluminum foil constituting the aluminum foil layer 13, a commonly used soft aluminum foil can be used. It is preferable to use an aluminum foil containing iron for the purpose of imparting further pinhole resistance and ductility during molding.

The iron content in the aluminum foil (100% by mass) is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. When the iron content is 0.1% by mass or more, pinhole resistance and ductility are sufficiently imparted, and when it is 9.0% by mass or less, the flexibility is good.

The thickness of the aluminum foil layer 13 is preferably 9 to 200 μm, more preferably 15 to 100 μm, from the viewpoint of barrier property, pinhole resistance, and processability.

(Corrosion prevention treatment layer 13a)
The corrosion prevention treatment layer 13a is a layer provided to prevent corrosion of the aluminum foil layer 13 by the electrolytic solution or hydrofluoric acid.

Examples of the corrosion prevention treatment include degreasing treatment, hydrothermal transformation treatment, anodizing treatment, chemical conversion treatment, coating type corrosion prevention treatment in which a coating agent having corrosion prevention performance is applied, or a combination of two or more of these treatments. ..

Of the above-mentioned treatments, degreasing treatment, hydrothermal conversion treatment, and anodizing treatment, especially hydrothermal modification treatment and anodizing treatment, dissolve the surface of the metal foil (aluminum foil) with a treatment agent and have excellent corrosion resistance. Since it forms boehmite and alumite), it forms a co-continuous structure from the metal foil to the corrosion prevention treatment layer 13a, so it may be included in the definition of chemical conversion treatment, but it is a rare earth element described later. It is also possible to form the corrosion prevention treatment layer 13a only by a pure coating treatment not included in the definition of chemical conversion treatment, such as a method using a coating agent containing an oxide sol.

First, the degreasing treatment will be described. The degreasing treatment can be broadly classified into a wet type and a dry type.

Examples of the wet type degreasing treatment include acid degreasing and alkaline degreasing. Examples of the acid used for acid degreasing include inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid and hydrofluoric acid. One of these acids may be used alone, or two or more of these acids may be used in combination. Examples of the alkali used for alkaline degreasing include sodium hydroxide and the like having a high etching effect. In addition, those containing a weak alkaline type or a surfactant can be mentioned. Further, as acid degreasing, by using an acid degreasing agent in which a fluorine-containing compound such as monosodium ammonium difluoride is dissolved in the above-mentioned inorganic acid, not only the degreasing effect of the metal foil but also the immobility of metal fluoride is formed. It is possible to make it, and it is effective in terms of resistance to fluorine acidity. Examples of the alkaline degreasing include a method using sodium hydroxide and the like. The wet type degreasing treatment is performed by a dipping method or a spray method.

Examples of the dry type degreasing treatment include a method performed in an aluminum annealing process. Further, frame treatment, corona treatment, degreasing treatment in which pollutants are oxidatively decomposed and removed by active oxygen generated by irradiation with ultraviolet rays of a specific wavelength, and the like can be mentioned.

Examples of the hot water transformation treatment include boehmite treatment obtained by immersing a metal leaf in boiling water to which triethanolamine is added. Moreover, as an anodizing treatment, for example, an alumite treatment can be mentioned. Examples of the chemical conversion treatment include chromate treatment, zirconium treatment, titanium treatment, vanadium treatment, molybdenum treatment, calcium phosphate treatment, strontium hydroxide treatment, cerium treatment, ruthenium treatment, and various chemical conversion treatments composed of a mixed phase thereof. Be done. It is preferable that the above-mentioned degreasing treatment is performed in advance for these hot water transformation treatments, anodizing treatments, and chemical conversion treatments. Further, these chemical conversion treatments can be applied not only to the wet type but also to the coating type in which these treatment agents are mixed with a resin component.

Next, a coating type corrosion prevention treatment for applying a coating agent having corrosion prevention performance will be described.

Examples of the coating agent used in this treatment include those containing at least one selected from the group consisting of rare earth element oxide sol, anionic polymer, and cationic polymer. In particular, a method using a coating agent containing a rare earth element oxide sol is preferable.

The rare earth element oxide sol is one in which fine particles of rare earth element oxide (for example, particles having an average particle size of 100 nm or less) are dispersed in a liquid dispersion medium.

Examples of the rare earth element oxide include cerium oxide, yttrium oxide, neodymium oxide, and lanthanum oxide. Of these, cerium oxide is preferable.

As the liquid dispersion medium of the rare earth element oxide sol, various solvents such as water, alcohol-based solvent, hydrocarbon-based solvent, ketone-based solvent, ester-based solvent, and ether-based solvent can be used. Of these, water is preferable.

Rare earth element oxide sol is an inorganic acid such as nitric acid, hydrochloric acid and phosphoric acid, and organic acid such as acetic acid, malic acid, ascorbic acid and lactic acid as a dispersion stabilizer in order to stabilize the dispersion of rare earth element oxide particles. It is preferable to contain acids, salts thereof and the like.

In the corrosion prevention treatment layer 13a described above, the corrosion prevention treatment layer 13a by chemical conversion treatment typified by chromate treatment forms an inclined structure with aluminum foil, and therefore, in particular, hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid or salts thereof. The aluminum foil is treated with a chemical conversion treatment agent containing the above, and then a chromium or non-chromate compound is allowed to act on the aluminum foil to form a chemical conversion treatment layer on the aluminum foil. However, since the chemical conversion treatment uses an acid as the chemical conversion treatment agent, the working environment is deteriorated and the coating apparatus is corroded.

On the other hand, unlike the chemical conversion treatment typified by the chromate treatment, the coating type corrosion prevention treatment layer 13a described above does not need to form an inclined structure with respect to the aluminum foil layer 13. Therefore, the properties of the coating agent are not restricted by acidity, alkalinity, neutrality, etc., and a good working environment can be realized. In addition, for the chromate treatment using a chromium compound, the coating type corrosion prevention treatment layer 13a is preferable from the viewpoint that an alternative plan is required in terms of environmental hygiene.

If necessary, the corrosion prevention treatment layer 13a may have a laminated structure in which a cationic polymer is further laminated.

Examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of polyethyleneimine and a polymer having a carboxylic acid, a primary amine graft acrylic resin obtained by grafting a primary amine on an acrylic main skeleton, polyallylamine or a derivative thereof. Aminophenol resin and the like can be mentioned.

Mass per unit area of the corrosion prevention treatment layer 13a is preferably in the range of 0.005~0.200g / ^{m 2,} the range of 0.010~0.100g / ^{m 2} is more preferable. If it is 0.005 g / m ² or more, it is easy to impart a corrosion prevention function to the aluminum foil layer 13. Further, even if the mass per unit area ^{exceeds 0.200 g / m 2} , the corrosion prevention function is saturated and does not change much. On the other hand, when a rare earth oxide sol is used, if the coating film is thick, the cure due to heat during drying becomes insufficient, and the cohesive force may decrease.

(Base treatment layer 13b)
The base treatment layer 13b plays a role of further enhancing the adhesion between the aluminum foil layer 13 and the plastic sheet 11 by improving the adhesiveness between the aluminum foil layer 13 and the adhesive layer 12. By further increasing the adhesiveness, the moldability of the exterior material is improved.

The base treatment layer 13b is a crosslinked resin (A) formed from a resin (A1) having two or more nitrogen-containing functional groups and a resin (A2) having a reactive functional group that reacts with the nitrogen-containing functional groups. Examples include layers containing. In addition to the crosslinked resin (A), fine particles (B) of rare earth element oxides may be contained, and in addition to these crosslinked resins (A) and fine particles (B), fine particles (B) It may contain a dispersion stabilizer (C). Further, it contains an organic silicon compound (D) that improves the adhesion to the aluminum foil layer 13 and a metal compound (E) that forms a cross-linked portion between the resin (A1) and the resin (A2). May be good.

Of these components, the crosslinked resin (A) contributes to the improvement of heat resistance and adhesion. That is, the nitrogen-containing functional group of the resin (A1) reacts with the reactive functional group of the resin (A2) to form a crosslinked site containing a nitrogen atom. By forming the crosslinked portion, the adhesion between the plastic sheet 11 and the aluminum foil layer 13 is improved. Further, the base treatment layer 13b containing the crosslinked portion containing nitrogen atoms imparts good heat-resistant adhesion to the aluminum foil layer 13. Examples of the nitrogen-containing functional group of the resin (A1) include an oxazoline group and an amino group.

As described above, the resin (A1) and the resin (A2) constituting the crosslinked resin (A) are crosslinked with each other. For this reason, it is desirable that these are properly combined. For example, an oxazoline group-containing resin containing two or more oxazoline groups is used as the resin (A1), and the co-weight of poly (meth) acrylic acid or (meth) acrylic acid and another polymerizable monomer as the resin (A2). Acrylic resins selected from the group consisting of coalescing and their ion-neutralized products can be used to combine and crosslink each other. Further, an amino group-containing resin containing two or more amino groups can be used as the resin (A1), and a glycidyl group-containing compound can be used as the resin (A2), and these can be combined and crosslinked with each other.

A combination of an oxazoline group-containing resin and an acrylic resin is desirable. This is because the adhesion between the plastic sheet 11 and the aluminum foil layer 13 is improved by having an amide ester moiety formed by the reaction of the oxazoline group of the oxazoline group-containing resin and the carboxy group of the acrylic resin. is there. Further, from the viewpoint of further improving the adhesion, it is preferable to utilize that the aluminum foil constituting the aluminum foil layer 13 is an amphoteric compound. That is, not only the effect of the amide ester moiety but also the carboxy group of the acrylic resin acts as an "acidic group" to impart an acid-base interaction, thereby further improving the adhesion. For this purpose, as will be described later, it is preferable to add the carboxy group contained in the acrylic resin in an equal amount to an excess of the oxazoline group contained in the oxazoline group-containing resin.

The oxazoline group-containing resin is obtained by copolymerizing, for example, an oxazoline group-containing monomer such as isopropenyl oxazoline with other polymerizable monomers such as various acrylic monomers, styrene, and acrylonitrile that can be copolymerized with the oxazoline group-containing monomer. Obtained by

The acrylic resin is preferably a homopolymer resin or a copolymer resin containing (meth) acrylic acid and an ionic salt (ammonium salt, sodium salt, etc.) of (meth) acrylic acid as a main component. Further, it may be an ion neutralized product of this.

Examples of other polymerizable monomers copolymerized with (meth) acrylic acid include alkyl (meth) acrylate-based monomers and hydroxyl group-containing (meth) acrylic-based monomers. Further, as another polymerizable monomer, styrene, α-methylstyrene, vinylmethyl ether, vinyl ethyl ether and the like may be used.

Examples of the ion-neutralized product of this acrylic resin include ion salts such as ammonium salt and sodium salt of the resin.

The blending ratio of the oxazoline group-containing resin and the acrylic resin varies depending on the copolymerization component of each component and its molar ratio (or mass ratio) and is not particularly limited, but the oxazoline group-containing resin: acrylic resin = 1: 99 to 99: 1 is preferable, and 1:99 to 45:55 is more preferable. If the ratio of the oxazoline group-containing resin to the total amount of the oxazoline group-containing resin and the acrylic resin is 1% by mass or more, a sufficient cross-linking density can be easily obtained, and the amount of the amide ester moiety increases, resulting in heat resistance and heat resistance. Adhesion is improved. Further, the smaller the ratio of the resin oxazoline group-containing resin to the total amount of the oxazoline group-containing resin and the acrylic resin, the easier it is to obtain the effect of the above-mentioned carboxylic acid, and if it is 45% by mass or less, it does not react with the oxazoline group. The carboxy group makes it easy to improve the adhesion.

Next, the amino group-containing resin containing two or more amino groups is not particularly limited as long as it is a resin having at least two amino groups in one molecule, for example, polyallylamine, aminophenol resin and the like. Can be mentioned. Further, as the glycidyl group-containing compound, a resin having at least two glycidyl groups in one molecule is preferable, and examples thereof include polyglycerol polyglycidyl ether.

Examples of the fine particles (B) of the rare earth element oxide include cerium oxide, yttrium oxide, neodymium oxide, and lanthanum oxide. Of these, cerium oxide is preferable. The average particle size may be, for example, 100 nm or less.

The dispersion stabilizer (C) is blended as a dispersion stabilizer that stabilizes the dispersion of the fine particles (B), and is preferably composed of phosphoric acid or phosphate. When phosphoric acid or phosphate is used as the dispersion stabilizer (C) and the sheet 1 of the present invention is used as an exterior material for a lithium ion battery, the aluminum foil layer 13 utilizes the chelating ability of phosphoric acid. In addition, it improves the adhesion with and imparts electrolyte resistance by capturing metal ions eluted by the influence of hydrofluoric acid (passivation formation), and phosphoric acid easily undergoes dehydration condensation even at low temperatures, resulting in base treatment. Effects such as improving the cohesive force of the layer 13b can be obtained.

As the dispersion stabilizer (C), for example, orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, alkali metal salts and ammonium salts thereof can be used.

The content of the dispersion stabilizer (C) in the base treatment layer 13b is preferably 1 part by mass or more, more preferably 5 parts by mass or more, based on 100 parts by mass of the fine particles (B).

In the base treatment layer 13b, the total amount of the fine particles (B) and the dispersion stabilizer (C) with respect to 100 parts by mass of the crosslinked resin (A) is preferably 200 to 12000 parts by mass.

Next, the organic silicon compound (D) plays a role of improving the adhesion with the aluminum foil layer 13 when the base treatment layer 31 is provided by various processes. Examples of the organic silicon compound (D) include an organosilane represented by the following formula (1), a hydrolyzate of the organosilane, a derivative thereof (hereinafter referred to as “organic silicon compound (D1)”), and the following. At least one compound selected from the group consisting of a metal alkoxide represented by the formula (2), a hydrolyzate of the metal alkoxide, and a derivative thereof (hereinafter referred to as "organic silicon compound (D2)") is used. it can.

R ^1- Si (OR ² ) ₃ ... (1)
M (OR ³ ) _n ... (2)
(However, in the formula, R ¹ is an organic group containing an alkyl group, a (meth) acryloyloxy group, a vinyl group, an amino group, an epoxy group or an isocyanate group, R ² is an alkyl group, and M is a metal ion. Yes, R ³ is an alkyl group, and n is the same number as the valence of the metal ion.)
^{Examples of R 1} in the organic silicon compound (D1) include an alkyl group, a (meth) acryloyloxyalkyl group, a vinyl group, an aminoalkyl group, a glycidoxyalkyl group, and an isocyanatealkyl group.

The content of the organic silicon compound (D) in the base treatment layer 13b is preferably 0.1 to 100 parts by mass, more preferably 0.3 to 50 parts by mass with respect to 100 parts by mass of the crosslinked resin (A). When the content of the organic silicon compound (D) is 0.1 part by mass or more with respect to 100 parts by mass of the crosslinked resin (A), the effect of improving the adhesion can be easily obtained. On the other hand, even if the content of the organic silicon compound (D) exceeds 100 parts by mass with respect to 100 parts by mass of the crosslinked resin (A), the effect of improving the adhesion is saturated.

Next, as the metal compound (E) forming the cross-linking site between the resin (A1) having a nitrogen-containing functional group and the resin (A2) having a reactive functional group, in the coating composition forming the base treatment layer 13b. A metal compound that ionically dissociates in this solution state can be used when blended in. By applying the coating composition onto the aluminum foil layer 13 by various coating methods and then volatilizing the liquid medium, the resin (A1) and the resin (A2) react with each other, and the metal dissociated from the metal compound (E). Ions act on the crosslinked resin (A) (for example, act on the unreacted carboxy group of the acrylic resin and the unreacted amino group of the oxazoline group-containing resin) to form an ion crosslink.

The metal compound (E) dissociates ions (has solubility in a solvent) when blended in the coating composition, and the dissociated metal ions act on the crosslinked resin (A) to form an ion crosslink. A water-soluble metal compound is preferable. For example, a metal compound in which the aqueous solution becomes acidic (acidic metal compound) and a metal compound in which the aqueous solution becomes basic (basic metal compound) can be mentioned.

Examples of the acidic metal compound include hydrochlorides, sulfates, nitrates, hydrofluorates and the like of various metals. Examples of the metal of the metal compound include zinc, iron, manganese, copper, chromium, zirconium, cobalt and the like. Further, the metal may be an alkaline (earth) metal such as sodium or calcium.

Examples of the basic metal compound include zirconium compounds such as ammonium carbonate and ammonium fluoride.

Aqueous solutions containing acidic metal compounds are acidic. In this case, considering that the crosslinked resin (A) is also a water-soluble acidic solution, a resin composed of an oxazoline group-containing resin and an acrylic resin is used, and the acrylic resin is poly (meth) acrylic acid. Or, it is necessary to use a copolymer of (meth) acrylic acid and another polymerizable monomer. However, since the oxazoline group-containing resin has an oxazoline group (basic), the oxazoline group-containing resin and the acrylic resin may gradually react with each other in the coating composition before coating, which may reduce the coating suitability ( Effect of coating composition on pot life). In this respect, an ionic salt (ion neutralized product) such as an ammonium salt or a sodium salt is used as the resin acrylic resin to suppress the reaction between the carboxyl group and the oxazoline group in the coating composition before coating, and the coating is performed. It is preferable that the carboxyl group and the oxazoline group react with each other when the composition is dried and formed into a film. Further, the acrylic resin in this case is more preferably an ammonium salt that does not easily remain as an impurity when the coating composition is dried or formed into a film.

As described above, since the coating composition forming the base treatment layer 13b is preferably a basic solution at the stage before coating, the aqueous solution containing the metal compound (E) is also preferably basic. .. Therefore, as the metal compound (E), a basic metal compound is preferable from the viewpoint of pot life and stability of the coating composition, and a zirconium compound such as ammonium carbonate or zirconium fluoride is particularly preferable.

The content of the metal compound (E) in the base treatment layer 13b in terms of metal is preferably 0.1 to 100 parts by mass with respect to 100 parts by mass of the crosslinked resin (A). When the content of the metal compound (E) in terms of metal is 0.1 part by mass or more with respect to 100 parts by mass of the crosslinked resin (A), the effect of improving the adhesion by the metal compound (E) can be easily obtained. If the metal-equivalent content of the metal compound (E) is 100 parts by mass or less with respect to 100 parts by mass of the crosslinked resin (A), the metal compound (E) remains as an unreactant in the base treatment layer 31. It is easy to suppress the decrease in cohesive force.

The base treatment layer 13b is made of aluminum, which is a coating composition containing a resin (A1) and a resin (A2) forming a crosslinked resin (A), a liquid medium (solvent or dispersion medium), and if necessary, other components. It can be formed by applying it on the foil layer 13 and drying and curing it. When the base treatment layer 13b further contains fine particles (B), the fine particles (B) may be blended in the same coating composition as the resin (A1) and the resin (A2), or may be blended in different coating compositions. .. When blended into different coating compositions, the coating compositions can be sequentially coated and dried to form a layer containing the crosslinked resin (A) and the fine particles (B).

The thickness of the base treatment layer 13b is preferably 0.001 to 1 μm. When the thickness of the base treatment layer 13b is 0.001 μm or more, the adhesion between the base material layer 11 and the aluminum foil layer 13 is sufficiently improved. When the thickness of the base treatment layer 13b is 1 μm or less, the moldability is improved, and the amount of heat required for the crosslinking reaction does not become too large, and the drying cure step is facilitated, so that the productivity is improved.

(Adhesive layer 12)
The adhesive layer 12 is a layer for adhering the plastic sheet 11 and the aluminum foil layer 13. The adhesive layer 12 can be formed by using a known adhesive used for laminating a resin film and an aluminum foil. Examples of the adhesive include polyurethane-based adhesives containing a main agent composed of a polyol such as a polyester polyol, a polyether polyol, an acrylic polyol, and a carbonate polyol, and a curing agent composed of a bifunctional or higher functional isocyanate compound. A polyurethane resin is formed by allowing the curing agent to act on the main agent.

Then, the adhesive layer 12 can be formed by dissolving or dispersing each of these components in a solvent and applying the mixture to one of the plastic sheet 11 and the aluminum foil 13. Then, the plastic sheet 11 and the aluminum foil 13 can be laminated and adhered by overlapping and crimping the other. As the coating method, methods such as dry lamination, non-solvent lamination, and wet lamination can be adopted, but it is particularly desirable to adopt dry lamination.

The thickness of the adhesive layer 12 is preferably 1 to 10 μm, more preferably 3 to 5 μm. When it is 1 μm or more, the laminating strength as an adhesive is improved, and when it is 10 μm or less, when the exterior material 1 is made into a deep-drawn molded product by cold molding, even at the drawn corners of the deep-drawn molded product. , The floating between the plastic sheet 11 and the aluminum foil layer 13 in the electrolytic solution atmosphere can be sufficiently suppressed.

(Adhesive layer 14)
The adhesive layer 14 is a layer for adhering the aluminum foil layer 13 on which the corrosion prevention treatment layer 13a is formed and the sealant layer 15. Adhesion by the adhesive layer 14 is easily possible by dry laminating.

Examples of the adhesive constituting the adhesive layer 14 include the same adhesives as those mentioned in the adhesive layer 12.

However, since the adhesive used for the adhesive layer 14 is an adhesive that adheres the surfaces to which the electrolytic solution is filled, it is necessary to pay attention to swelling due to the electrolytic solution and hydrolysis due to hydrofluoric acid. Therefore, it is preferable to use an adhesive using a main agent having a skeleton that is not easily hydrolyzed, an adhesive having an improved crosslink density, and the like.

The adhesive layer 14 can also be formed in the same manner as the adhesive layer 12. That is, each component is dissolved or dispersed in a solvent, applied to one of the aluminum foil 13 and the sealant layer 15, and the other is overlapped and pressure-bonded, whereby these can be laminated and adhered. The coating method may be dry lamination, non-solvent lamination, wet lamination or the like.

The thickness of the adhesive layer 14 is preferably 1 to 10 μm, more preferably 3 to 5 μm. When it is 1 μm or more, the electrolytic solution resistance and the laminating strength are improved, and when it is 10 μm or less, the amount of water permeating from the end face of the laminating material is improved.

(Adhesive resin layer 14')
The adhesive resin layer 14'is a layer for adhering the aluminum foil layer 13 on which the corrosion prevention treatment layer 13a is formed and the sealant layer 15 instead of the adhesive layer 14.

As the heat-adhesive resin constituting the adhesive resin layer 14', for example, an unsaturated carboxylic acid or an acid anhydride thereof, or an ester of an unsaturated carboxylic acid or an acid anhydride thereof is used as a radical initiator with respect to a polyolefin resin. Examples thereof include a modified polyolefin resin obtained by graft modification in the presence of the resin.

The adhesive resin layer 14'can be provided by a method (sand laminating method) in which these adhesive resins are extruded in a molten state and the aluminum foil 13 and the sealant layer 15 are pressure-bonded to both surfaces thereof. By this sand lamination, the adhesive resin layer 14'is formed, and at the same time, the aluminum foil 13 and the sealant layer 15 are laminated and adhered.

The extrusion temperature of the adhesive resin is preferably 200 to 340 ° C. The thickness of the adhesive resin layer 14'is preferably 3 to 50 μm, more preferably 10 to 40 μm. When the thickness of the adhesive resin layer 14'is equal to or greater than the lower limit, excellent adhesiveness can be easily obtained. When the thickness of the adhesive resin layer 14'is equal to or less than the upper limit value, the amount of water permeating from the side end surface of the exterior material 1 is reduced.

(Manufacturing method of drawing sheet 1, 1', 1 ")
Each of the draw forming sheets 1, 1', 1 "is an outer surface laminating step of laminating and adhering a plastic sheet 11 to one side of an aluminum foil 13 which has been subjected to a predetermined treatment, and laminating and adhering a sealant layer 15 to the opposite surface. It can be manufactured through an inner surface laminating step, a silicone oil coating step of forming a coating film 11a on the surface of the plastic sheet 11, and a slip agent coating step of forming a coating film 11b on the coating film 11a. The order may be arbitrary, but the silicone oil coating step and the slip agent coating step must be performed in this order.

(How to use drawing sheets 1, 1', 1 ")
Each of the draw-forming sheets 1, 1', 1 "can be drawn and molded so that the coating film 11b is located on the outer surface, and can be used as an exterior material of a lithium ion battery. A press molding method such as an overhang molding method or a deep drawing molding method can be adopted by using a molding mold. Then, after the battery element is housed in the housing portion (recess), the battery element is sealed and sealed to manufacture a lithium ion battery. Further, various images can be printed on the outer surface of the lithium ion battery thus obtained, that is, on the outer surface of the draw forming sheet 1, 1', 1 ". An inkjet printing method can be used for printing, and an ink containing methyl ethyl ketone as a solvent or an ink containing a mixed solvent containing the same as a main component can be used as the ink.

Hereinafter, the present invention will be described with reference to experimental data. This experimental data can be used to inductively consider the causal relationship between the type and application amount of silicone oil and the physical properties of the draw-forming sheet, and the causal relationship between the application amount of the slip agent and the physical properties of the draw-forming sheet. For the purpose, both Examples and Comparative Examples are referred to as "Experimental Examples" without distinction.

(Sheet for drawing)
The base material sheet used in this experimental data is the one described in the first example described above. That is, the plastic sheet 11, the aluminum foil 13, and the sealant layer 15 were laminated and bonded via the adhesive layers 12 and 14, respectively.

As the plastic sheet 11, a nylon-based multilayer film (“Heptax” manufactured by Gunze Corporation) was used.

Further, as the aluminum foil 13, a soft aluminum foil 8079 material (made of Toyo Aluminum) having a thickness of 40 μm that has been annealed and degreased is used, a corrosion prevention treatment layer 13a is formed on one side thereof, and a base treatment layer 13b is formed on the other side. Used.

That is, first, the following coating liquid CL-1, coating liquid CL-2, and coating liquid CL-3 were applied in this order to form the corrosion prevention treatment layer 13a.

Coating liquid CL-1: 10 parts by mass of sodium phosphate is mixed with 100 parts by mass of cerium oxide, and distilled water is used as a solvent to adjust the solid content concentration to 10% by mass. Liquid CL-2: A mixture consisting of 90% by mass of ammonium polyacrylic acid salt (manufactured by Toa Synthetic) and 10% by mass of acrylic-isopropenyloxazoline copolymer (manufactured by Nippon Catalyst), using distilled water as a solvent and solid content. Composition adjusted to a concentration of 5% by mass Distilled water using a mixture of 90% by mass of polyallylamine (manufactured by Nitto Boseki) and 10% by mass of polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX) as a solvent. The composition was adjusted to a solid content concentration of 5% by mass using.

Further, the following base treatment agent PL-1 was applied to form the base treatment layer 13b.

Base treatment agent PL-1: A mixture consisting of 90% by mass of ammonium polyacrylate (manufactured by Toa Synthetic) and 10% by mass of acrylic-isopropenyloxazoline copolymer (manufactured by Nippon Catalyst) and 100 parts by mass of cerium oxide. A coating composition mixed with sodium polyphosphate-stabilized cerium oxide sol containing 10 parts by mass of a sodium salt of phosphoric acid. The blending amount of the sodium polyphosphate stabilized cerium oxide sol was 4000 parts by mass with respect to 100 parts by mass of the mixture.

As the sealant layer 15, a multilayer film (manufactured by Okamoto) composed of 2 types and 3 layers composed of random PP / block PP / random PP having a total thickness of 30 μm was used.

As the adhesive layer 12, a polyurethane adhesive (manufactured by Toyo Ink Co., Ltd.), which is a mixture of a polyester polyol-based main agent and an adduct-based curing agent of tolylene diisocyanate, is used, and a plastic sheet 11 and an aluminum foil are used by a dry lamination method. 13 was laminated and adhered.

The adhesive layer 14 is an adhesive composition obtained by blending 100 parts by mass of a maleic anhydride-modified polyolefin resin dissolved in toluene with 10 parts by mass (solid content ratio) of a polyisocyanate compound having an isocyanurate structure. The aluminum foil 13 and the sealant layer 15 were laminated and adhered by a dry lamination method.

Then, silicone oil and a slip agent were sequentially applied to the 11 surfaces of the plastic sheet of the base material sheet to form a silicone oil coating film 11a and a slip agent coating film 11b.

As the silicone oil, the following five types of SR-1 to SR-5 were used, and each of these silicone oils was dissolved in isopropyl alcohol and applied. The types and coating amounts of silicone oil used in each experimental example are shown in the table below.

SR-1 ... Dimethyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-96L-1.5CS), refractive index 1.391
SR-2: Polyether-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X-22-4272), refractive index 1.403
SR-3: Higher fatty acid ester-modified silicone oil (manufactured by Momentive Performance Materials Japan, trade name: TSF410), refractive index 1.425
SR-4: Polyether-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-351A), refractive index 1.450
SR-5: Polyether-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name KF-354L), refractive index 1.463
Moreover, erucic acid amide was used as a slip agent, and it was dissolved in isopropyl alcohol and applied. The amount of the slip agent applied in each experimental example is shown in the table below.

(Measurement of physical properties of drawing sheet)
For each of the draw-forming sheets thus obtained, the coefficient of static friction, printability, and the presence or absence of slip agent transfer were measured. The measurement method and evaluation method are as follows.

<Measurement of static friction coefficient>
The coefficient of static friction is measured by winding the prepared sheet around a weight made of a metal block having a width of 60 mm, a length of 100 mm and a mass of 1000 g, based on the inclination angle method described in JIS P8147: 2010, and static friction of the slip agent-coated surface. This was done by measuring the coefficients.

Then, when the coefficient of static friction was less than 0.25, it was evaluated as "◯", and when it was 0.25 or more, it was evaluated as "x".

<Measurement of printability>
Ten evaluation samples were prepared from each of the draw forming sheets, the printability of these ten evaluation samples was evaluated, and then the printability was comprehensively determined from the evaluation data.

That is, first, these evaluation samples were printed with a barcode by an inkjet method using an ink containing methyl ethyl ketone as a solvent, and whether or not the barcode could be read by a barcode scanner was evaluated. In addition, whether or not the printed image was spread or repelled was evaluated by macroscopic observation. The evaluation criteria are as follows.

◯: The barcode can be read, and the printed image does not spread or repel due to bleeding.
△ _1: While for every ten evaluation samples are possible reading of the bar code, of which bleeding in at least one sample was observed.
△ _2: For every 10 evaluation samples are possible reading of the bar code, repelling the print image in at least one sample was observed.
△ _12: For all the 10 evaluation samples are possible reading of the bar code, bleeding of the printed image on at least one sample was observed, repellency of a printed image to other samples was observed.
× ₁ : Of the 10 evaluation samples, bleeding was observed in at least one sample, and the barcode could not be read.
× ₂ : The repelling of the printed image was observed for at least one sample, and the barcode could not be read.
× ₁₂ : Spreading of the printed image due to bleeding was observed for at least one sample, cissing of the printed image was observed for the other samples, and the barcode could not be read for these samples.

<Measurement of the presence or absence of slip agent transfer>
A black cloth cut into 40 mm squares was placed on each drawing sheet and rubbed for 3 m while applying a load of 500 g, and it was observed whether or not white discoloration occurred on this black cloth due to the transfer of the slip agent. .. Those without discoloration were evaluated as "○", and those with presence were evaluated as "×".

The results of these measurements are shown in Tables 1 to 6. Table 1 shows the measurement results of the draw forming sheet using dimethyl silicone oil (SR-1).

Next, Table 2 shows the measurement results of the draw forming sheet using the polyether-modified silicone oil (SR-2).

In addition, Table 3 shows the measurement results of the draw forming sheet using the higher fatty acid ester-modified silicone oil (SR-3).

Table 4 shows the measurement results of the draw forming sheet using the polyether-modified silicone oil (SR-4).

Table 5 shows the measurement results of the draw forming sheet using the polyether-modified silicone oil (SR-5).

Finally, Table 6 shows the measurement results of the draw forming sheet to which only the slip agent was applied without applying silicone oil.

<Discussion>
From this result, it can be understood that the coefficient of static friction tends to decrease as the amount of the slip agent applied increases, regardless of the type of slip agent.

Next, from Table 1, it can be seen that when dimethyl silicone oil is used as the silicone oil, the printability is inferior regardless of the amount of the silicone oil applied and the amount of the slip agent applied.

On the other hand, when a higher fatty acid ester-modified silicone oil or a polyether-modified silicone oil is used as the silicone oil, it can be seen that the printability differs depending on the amount of the silicone oil applied (see Tables 2 to 5). That is, if the amount of the silicone oil applied is too small, the spread of the printed image due to bleeding is observed, and if it is excessive, the coating film 11a repels the ink and the printability is lowered. When higher fatty acid ester-modified silicone oil or polyether-modified silicone oil is used as the silicone oil and the coating amount is 0.15 to 3.00 mg / m ² , the printability is improved in any case. It is possible to read barcodes with a barcode scanner, but the amount of application without bleeding or repellency depends on the refractive index of the silicone oil.

That is, in the case of the polyether-modified silicone oil (SR-2) having a refractive index of 1.403, bleeding or cissing does not occur in ^{the coating amount range of 0.15 to 1.20 mg / m 2.} If the coating amount is larger than this (3.00 mg / m ² ), the barcode can be read, but cissing occurs.

In the case of higher fatty acid ester-modified silicone oil (SR-3) having a higher refractive index than this (refractive index 1.425), the range of the coating amount that does not cause bleeding or repellency is wide, and the coating amount is 0.15 to 3. No bleeding or repelling occurs in the range of 00 mg / m ^2.

However, when the refractive index is further increased, bleeding occurs when the coating amount is small. In the case of a polyether-modified silicone oil (SR-4) having a refractive index of 1.45, bleeding and cissing do not occur in the range of ^{the coating amount of 1.20 to 3.00 mg / m 2, but the coating amount is smaller than this (} Bleeding occurs at 0.15 mg / m ^2).

Then, in the case of the polyether-modified silicone oil (SR-5) having a refractive index of more than 1.45, either bleeding or repellency occurs regardless of the coating amount.

Therefore, a higher fatty acid ester-modified silicone oil or a polyether-modified silicone oil is used as the silicone oil, and the coating amount thereof is 0.15 to 3.00 mg / m ^2.
When a slip agent with a coating amount of 3.0 mg / m ² or more is applied, the coefficient of static friction can be reduced to improve the draw forming suitability, and the draw forming suitability is not impaired. It is possible to obtain a sheet for use. It can be understood that the coating amount margin is the widest in the range of the refractive index of 1.42 to 1.43, and the coating amount margin is narrowed in either case where the refractive index is smaller or larger than this. ..

However, it can be understood from Tables 1 to 5 that when the application amount of the slip agent is 15.0 mg / m ² , the slip agent bleeds and easily transfers to an adjacent sheet or the like. The coating amount of the slip agent because the in the case of 10.0 mg / ^{m 2} does not occur transition slip agents, transfer of slip agent if the range that the coating amount of 3.0~10.0mg / ^{m 2} Can be inferred that does not occur.

1,1', 1 "... Plastic sheet 11 ... Silicone oil coating film 11b ... Slip agent coating film 12 ... Adhesive layer 13 ... Aluminum foil 13a ... Corrosion prevention treatment layer 13b ... Base treatment layer 14 ... Adhesive layer 14'... Adhesive resin layer 15 ... Sealant layer

Claims (5)

A draw-forming sheet in which silicone oil and a slip agent other than silicone oil are applied in this order on one side of a base sheet having draw-molding suitability.
The silicone oil is made from fatty acid ester-modified silicone oil or polyether-modified silicone oil, the coating weight of 0.15~3.00mg / ^{m 2,}
The coating amount of the slip agent other than silicone oil Ri 3.0~10.0mg / ^{m 2} der,
A drawing sheet for drawing, wherein the silicone oil is composed of a single component silicone oil or a mixture of two or more components and has a refractive index of 1.40 to 1.463. The draw-forming sheet according to claim 1 , wherein the slip agent is a fatty acid amide. The draw-forming sheet according to claim 2 , wherein the fatty acid amide is an unsaturated fatty acid amide. The draw-forming sheet according to claim 3 , wherein the unsaturated fatty acid amide is erucic acid amide or oleic acid amide. The draw-forming sheet according to any one of claims 1 to 4, wherein the sheet is for the exterior of a lithium ion battery.

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