JP2015166261A - Packing material for molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packing material for molding without separating when a colored layer is partially cracked, even when used under a slightly severe environment such as the high temperature-high humidity, in molding time and sealing time.SOLUTION: A packing material 1 for molding is provided by laminating a heat-resistant resin layer 2, a first adhesive layer 5, a metal foil layer 4, a second adhesive layer 6 and a thermoplastic resin layer 3 on the inside from the outside, and the first adhesive layer 5 is composed of a coloring adhesive composition including a coloring pigment and an adhesive including a two-liquid curable polyester urethane resin of a polyester resin as a main agent and a multifunctional isocyanate compound as a hardening agent, and the polyester resin is 8,000-25,000 in number average molecular weight (Mn), and is 15,000-50,000 in weight average molecular weight (Mw), and these ratio (Mw/Mn) is 1.3-2.5, and the multifunctional isocyanate compound includes aromatic isocyanate of 50 mol% or more.

Description

  The present invention is suitably used as a case for, for example, notebook computers, mobile phones, in-vehicle, stationary secondary batteries (lithium ion secondary batteries), and also suitable as food packaging materials and pharmaceutical packaging materials. The present invention relates to a molding packaging material and a molding case used in the above.

  Batteries such as lithium ion secondary batteries are increasingly required to be colored in order to unify the appearance and color of devices such as electrical devices to be mounted. For example, in order to give a profound feeling and a high-class feeling, the device is often black, and in this case, the battery is also often black.

  This type of packaging material is generally a laminate in which resin layers are laminated on both sides of a metal foil. To color a battery in black or the like, a base resin that colors the resin layer used in the packaging material Provide a printed layer under the layer, color the adhesive layer between the base resin layer and the shielding metal layer, and if the base resin layer is composed of multiple layers, color the adhesive layer between layers There are means such as.

For example, there is an example in which a layer containing an identification mark is provided on any of a base material layer (resin layer), an adhesive layer, and a metal foil layer of a battery packaging material, and a printed layer provided below the base material layer And the adhesive layer of the base material layer can be colored as a whole to color the entire packaging material. (See Patent Documents 1 and 2)
Some have a black body material layer between the metal foil layer and the outer layer film to promote heat dissipation of the battery packaging material (see Patent Document 3).

International Publication WO 2011/016506 A1 JP 2011-045463 A JP 2011-0965552 A

When the above-described packaging material is colored black, it is common to provide a printing layer with a printing ink containing a pigment such as carbon black.
However, when a printing layer containing carbon black as a pigment is provided on the inner surface of the outer resin layer constituting the battery packaging material in order to color the battery in black, there are the following problems.

  That is, when the black packaging material is molded into a container (case) shape by deep drawing molding or stretch molding, the carbon black-containing printing layer is partially cracked and peeled off, and the underlayer (not black) is visible. As a result, there is a problem that uniform black coloring is impaired.

  Such partial peeling of the printed layer was used when sealing the black packaging material after encapsulating the electrode and electrolyte, or when the battery packaged with the black packaging material was used in a slightly harsh environment such as high temperature and high humidity. Sometimes it happens.

  The same problem occurs not only in the black packaging material using carbon black but also in the packaging material colored with other pigments.

  The present invention has been made in view of such technical background, and the colored layer is partially formed even during molding and sealing, and even when used in a slightly severe environment such as high temperature and high humidity. An object of the present invention is to provide a molding packaging material that does not crack and peel.

  That is, this invention has the structure as described in [1]-[7].

[1] A heat resistant resin layer as an outer layer, a thermoplastic resin layer as an inner layer, a metal foil layer disposed between these two layers, and the metal foil layer and the heat resistant resin layer. A molding packaging material comprising: a first adhesive layer provided; and a second adhesive layer disposed between the metal foil layer and the thermoplastic resin layer,
The first adhesive layer is composed of a colored adhesive composition containing a color pigment, an adhesive containing a two-component curable polyester urethane resin with a polyester resin as a main agent and a polyfunctional isocyanate compound as a curing agent,
The polyester resin has a number average molecular weight (Mn) of 8,000 to 25,000, a weight average molecular weight (Mw) of 15,000 to 50,000, and a ratio (Mw / Mn) thereof of 1.3 to 2.5,
The molding packaging material, wherein the polyfunctional isocyanate compound contains 50 mol% or more of an aromatic isocyanate.

[2] In the two-component curable polyester urethane resin, the polyester resin as a main agent is a dicarboxylic acid and a dialcohol as raw materials,
2. The dicarboxylic acid according to item 1 above, wherein the dicarboxylic acid contains an aliphatic dicarboxylic acid having an even number of methylene in the methylene chain and an aromatic dicarboxylic acid, and the content of the aromatic dicarboxylic acid with respect to the total amount thereof is 40 to 80 mol%. Packaging material for molding.

  [3] The molding packaging material according to item 1 or 2, wherein in the colored adhesive composition, the content of the color pigment with respect to the total amount of the color pigment and the polyester resin is 5 to 60% by mass.

  [4] The molding packaging material according to any one of items 1 to 3, wherein the cured film of the two-component curable polyester urethane resin has a Young's modulus of 70 to 400 MPa according to a tensile test (JIS K7162).

  [5] The molding packaging material according to any one of items 1 to 4, which has a chemical conversion film on at least one surface of the metal foil layer.

  [6] A molding case formed by deep-drawing or stretch-molding the molding packaging material according to any one of items 1 to 5.

  [7] The molded case according to item 6 used as a battery case.

  In the invention of [1], the first adhesive layer is colored on the outer surface side of the packaging material for molding, and an adhesive containing a specific two-component curable polyester urethane resin is used for the adhesive coating film. Appropriate strength and elongation and excellent heat resistance can be obtained, and furthermore, the balance between adhesive application suitability (wide molecular weight distribution) and performance (narrow molecular weight distribution) can be maintained. Since the heat-resistant resin layer and the metal foil layer are joined together by the first adhesive layer, when the packaging material is molded such as deep drawing molding or overhang molding, when the packaging material is sealed for sealing The heat resistant resin layer does not peel off. Further, even when used in a slightly severe environment such as high temperature and high humidity, the heat resistant resin layer does not peel off.

  In the inventions [2], [3], and [4], the above effects are particularly excellent.

  In the invention of [5], since the metal foil layer has a chemical conversion film on the surface, the metal foil layer is prevented from corrosion of the metal foil, and a molding packaging material having high corrosion resistance is provided.

  The invention [6] provides a molded case in which the heat-resistant resin layer does not peel off even when used in a slightly severe environment such as high temperature and high humidity as well as during sealing.

  In the invention of [7], the battery case in which the heat-resistant resin layer is not partially cracked and peeled even when used in a slightly harsh environment such as high temperature and high humidity as well as during sealing. Is provided.

It is sectional drawing which shows one Embodiment of the packaging material for shaping | molding which concerns on this invention. It is a SS curve figure of the cured film of a two-component curing type polyester urethane resin adhesive. It is sectional drawing which shows other embodiment of the packaging material for shaping | molding which concerns on this invention. It is sectional drawing which shows other embodiment of the packaging material for shaping | molding which concerns on this invention.

[Basic structure of molding packaging material]
In FIG. 1, the packaging material 1 for shaping | molding which is one Embodiment of this invention and has a basic laminated structure is shown. The molding packaging material 1 is used as a packaging material for a lithium ion secondary battery case. That is, the molding packaging material 1 is used as a secondary battery case after being subjected to molding such as deep drawing.

  The molding packaging material 1 includes a heat-resistant resin layer (outer layer) 2 laminated and integrated on the upper surface of the metal foil layer 4 via a first adhesive layer 5, and a lower surface of the metal foil layer 4. (2) The thermoplastic resin layer (inner layer) 3 is laminated and integrated through an adhesive layer 6.

  Each layer is described in detail below.

(Heat resistant resin layer)
Although it does not specifically limit as the said heat resistant resin layer (outer layer) 2, For example, a polyamide film, a polyester film, etc. are mentioned, These stretched films are used preferably. Among them, the heat-resistant resin layer 2 includes a biaxially stretched polyamide film, a biaxially stretched polybutylene terephthalate (PBT) film, a biaxially stretched polyethylene terephthalate (PET) film, or a biaxially stretched polyethylene in terms of moldability and strength. It is particularly preferable to use a naphthalate (PEN) film. The polyamide film is not particularly limited, and examples thereof include 6 nylon film, 6,6 nylon film, and MXD nylon film. The heat resistant resin layer 2 may be formed as a single layer, or may be formed as a multilayer composed of, for example, a PET film / polyamide film.

  The heat-resistant resin layer 2 preferably has a thickness of 9 μm to 50 μm. When using a polyester film, the thickness is preferably 9 μm to 50 μm, and when using a polyamide film, the thickness is preferably 10 μm to 50 μm. It is possible to secure sufficient strength as a packaging material by setting it above the preferred lower limit value, and to improve the formability by reducing the stress at the time of stretch molding or drawing by setting the preferred lower limit value or less. Can do.

(Thermoplastic resin layer)
The thermoplastic resin layer (inner layer) 3 has excellent chemical resistance against highly corrosive electrolytes used in lithium ion secondary batteries and the like, and imparts heat sealability to the packaging material. To play a role.

  Although it does not specifically limit as said thermoplastic resin layer 3, It is preferable that it is a thermoplastic resin unstretched film layer. The thermoplastic resin unstretched film layer 3 is not particularly limited, but is made of polyethylene, polypropylene, an olefin copolymer, an acid-modified product thereof, and an ionomer in terms of chemical resistance and heat sealability. It is preferably constituted by an unstretched film made of at least one thermoplastic resin selected from the group.

  The thickness of the thermoplastic resin layer 3 is preferably set to 20 μm to 80 μm. When the thickness is 20 μm or more, pinholes can be sufficiently prevented from being generated, and by setting the thickness to 80 μm or less, the amount of resin used can be reduced, and the cost can be reduced. Especially, it is especially preferable that the thickness of the thermoplastic resin layer 3 is set to 30 μm to 50 μm. The thermoplastic resin layer 3 may be a single layer or a multilayer. As a multilayer film, the three-layer film which laminated | stacked the random polypropylene film on both surfaces of the block polypropylene film can be illustrated.

(Metal foil layer)
The metal foil layer 4 plays a role of imparting gas barrier properties to the molding packaging material 1 to prevent oxygen and moisture from entering. Although it does not specifically limit as said metal foil layer 4, For example, aluminum foil, copper foil, stainless steel foil etc. are mentioned, Aluminum foil is generally used. The thickness of the metal foil layer 4 is preferably 20 μm to 100 μm. When it is 20 μm or more, it can prevent the occurrence of pinholes during rolling when producing metal foil, and when it is 100 μm or less, it can reduce the stress at the time of stretch forming or draw forming and improve the formability. it can.

(First adhesive layer)
The said 1st adhesive bond layer 5 is a layer which gives a color (an achromatic color is included) to the outer surface side of the packaging material 1 for shaping | molding while carrying out joining to the heat resistant resin layer 2 which is the metal foil 4 and an outer layer. And a colored adhesive composition containing a color pigment and a specific adhesive.

  In the colored adhesive composition, the kind of the colored pigment is not limited, and an azo pigment, a phthalocyanine pigment, a condensed polycyclic pigment, an inorganic pigment, or the like can be used. Carbon black can be recommended as the black pigment. Moreover, it is preferable to use a color pigment having an average particle diameter of 0.1 to 5 μm, and a particularly preferable average particle diameter is 0.5 to 2.5 μm. When dispersing the pigment, it is preferable to disperse the pigment by using a pigment disperser, and when dispersing the pigment, a pigment dispersant such as a surfactant can also be used.

  In the colored adhesive composition, the adhesive is composed of an adhesive containing a two-component curable polyester urethane resin composed of a polyester resin as a main agent and a polyfunctional isocyanate compound as a curing agent. In the present invention, the molecular weight of the polyester resin that is the main component of the two-component curable polyester urethane resin is specified, and the type of the polyfunctional isocyanate compound that is the curing agent is specified, thereby improving the adhesive strength and moldability. Suppresses delamination when deep molding is performed.

  The polyester resin is a copolymer using dicarboxylic acid and dialcohol as raw materials, and preferred materials and compositions are as follows.

  It is preferable to use both aliphatic dicarboxylic acid and aromatic dicarboxylic acid as the dicarboxylic acid. In addition, the odd-even number of the methylene number of the methylene chain of the aliphatic dicarboxylic acid is a factor affecting the crystallinity of the resin, and the dicarboxylic acid having an even number of methylene produces a hard resin with high crystallinity. It is preferable to use an aliphatic dicarboxylic acid having the same. Examples of the aliphatic dicarboxylic acid having an even methylene number include succinic acid (methylene number 2), adipic acid (methylene number 4), suberic acid (methylene number 6), and sebacic acid (methylene number 8).

  Examples of the aromatic dicarboxylic acid include isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, and phthalic anhydride.

  Moreover, by making the content rate of aromatic dicarboxylic acid with respect to the total amount of aliphatic dicarboxylic acid and aromatic dicarboxylic acid into the range of 40-80 mol%, in other words, the content rate of aliphatic dicarboxylic acid is 20-60 mol. %, A resin having high adhesive strength and good moldability can be produced, and can be molded into a case having good moldability and a high side wall, and the metal foil layer 4 and the heat-resistant resin layer 2 It can be formed as a molding packaging material capable of suppressing the delamination of the film. Further, when the content of the aromatic dicarboxylic acid is less than 40 mol%, film physical properties are lowered and aggregation peeling is likely to occur, and therefore delamination is likely to occur. On the other hand, if the content of the aromatic dicarboxylic acid exceeds 80%, the resin becomes hard and the adhesion performance tends to decrease. A particularly preferred aromatic dicarboxylic acid content is 50 to 70 mol%.

  The dialcohol is ethylene glycol, propylene glycol, 1,3 butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, octanediol, Examples thereof include 1,4-cyclohexanediol and 2-butyl-2-ethyl-1,3-propanediol.

  The molecular weight of the polyester resin is defined such that the number average molecular weight (Mn) is 8,000 to 25,000, the weight average molecular weight (Mw) is 15,000 to 50,000, and the ratio (Mw / Mn) is set to 1.3 to 2.5. When the number average molecular weight (Mn) is 8,000 or more and the weight average molecular weight (Mw) is 15,000 or more, suitable coating strength and heat resistance can be obtained, and the number average molecular weight (Mn) is 25, When the weight average molecular weight (Mw) is 50,000 or less, an appropriate coating film elongation can be obtained without becoming too hard. Further, when the ratio (Mw / Mn) is 1.3 to 2.5, an appropriate molecular weight distribution is obtained, and the balance between adhesive application suitability (wide distribution) and performance (narrow distribution) can be maintained. . Particularly preferable number average molecular weight (Mn) of the polyester resin is 10,000 to 23,000, particularly preferable weight average molecular weight (Mw) is 20,000 to 40,000, and particularly preferable (Mw / Mn) is 1.5 to 2.3.

  The molecular weight of the polyester resin can be adjusted by chain extension with a polyfunctional isocyanate. That is, when the polyester component in the main agent is linked with NCO, a polymer having a hydroxyl group at the end is generated, and the molecular weight of the polyester resin can be adjusted by adjusting the equivalent ratio of the isocyanate group to the hydroxyl group of the polyester. In the present invention, it is preferable to use those connected so that their equivalent ratio (OH / NCO) is 1.01 to 10. Another method for adjusting the molecular weight is to change the reaction conditions for the polycondensation reaction of dicarboxylic acid and dialcohol (adjustment of the mixing molar ratio of dicarboxylic acid and dialcohol).

  Furthermore, an epoxy resin or an acrylic resin may be added as an additive of the adhesive main agent.

  As the polyfunctional isocyanate compound as the curing agent, various aromatic, aliphatic and alicyclic isocyanate compounds can be used. Specific examples include one or more diisocyanates such as aliphatic hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), aromatic tolylene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI). A polyfunctional isocyanate modified body is mentioned. In addition to adducts with polyfunctional active hydrogen compounds such as water, glycerin, and trimethylolpropane, examples of modification means include polyfunctional isocyanate modified products by a multimerization reaction such as isocyanuration, carbodiimidation, and polymerization. 1 type, or 2 or more types can also be mixed and used. However, in order to increase the adhesive strength after curing and obtain the effect of preventing peeling of the heat-resistant resin layer 2, it is necessary to contain 50 mol% or more of an aromatic isocyanate compound. A preferable content of the aromatic isocyanate compound is 70 mol% or more.

  In the two-component curable polyester urethane resin, the blending ratio of the main agent and the curing agent is blended at a ratio of 2 to 25 moles of isocyanate functional groups (—NCO) with respect to 1 mole of polyol hydroxyl group (—OH). preferable. If these molar ratios (—NCO) / (— OH) are less than 2 and the isocyanate functional groups (—NCO) are decreased, there is a risk that adequate coating strength and heat resistance cannot be obtained without sufficient curing reaction. is there. On the other hand, if (-NCO) / (-OH) exceeds 25 and the isocyanate functional group (-NCO) increases, the reaction with the functional group other than the polyol proceeds so much that the coating film becomes too hard and suitable elongation is obtained. There is a risk that it will not be obtained. A particularly preferred molar ratio (—NCO) / (— OH) of the polyol hydroxyl group to the isocyanate functional group is 5 to 20.

  In the two-component curable polyester urethane resin, the cured film after the reaction preferably has the following physical properties. The cured film preferably has a Young's modulus of 70 to 400 MPa according to a tensile test (JIS K7162) in order to ensure good moldability of the molding packaging material 1 and interlayer bonding strength. A particularly preferred Young's modulus is 100 to 300 MPa. Moreover, it is preferable that breaking strength is 20-70 MPa and breaking elongation is 50-400%. Particularly preferred breaking strength is 30 to 50 MPa, and particularly preferred breaking elongation is 100 to 300%. Further, it is preferable that the tensile stress-strain curve (SS curve) does not show a decrease in strength before breaking. FIG. 2 shows three patterns of SS curves. In pattern A, the strain amount is small and the strain amount in pattern B is large with respect to the tensile stress, but in all cases, the strain amount increases with the increase in tensile stress, and no decrease in strength before breakage is observed. On the other hand, in pattern C, the tensile stress is reduced in the process of increasing the strain amount, and the strength is reduced before breaking. In the present invention, it is preferable that the cured film of the two-component curable adhesive does not have a strength decrease in the SS curve. More preferably, there is no inflection point at which the intensity changes abruptly in the SS curve.

  The adhesive containing the two-component curable polyester urethane resin is a polycondensation of dicarboxylic acid and dialcohol, which are raw materials of the polyester resin, and if necessary, chain extension with a polyfunctional isocyanate, solvent and urethanization reaction Various additives such as catalysts, coupling agents for improving adhesive strength, epoxy resins, antifoaming agents, leveling agents, UV absorbers and antioxidants are mixed to form a fluid polyester resin solution, and this is a curing agent. A polyfunctional isocyanate compound or a solvent is further blended to prepare a low-viscosity fluid.

  Preferred conditions for the components constituting the colored adhesive composition are as follows. In addition, it is the ratio of the solid component which does not contain a solvent in the content rate described below.

  The preferred content of the color pigment with respect to the total amount of the color pigment and the polyester resin (the main component of the two-component curable polyester urethane resin) is 5 to 60% by mass. If the content of the color pigment is less than 5% by mass, the effect of concealing the metal foil layer 4 is small, and the metallic luster is visually recognized, and there is a possibility that the heavy feeling is impaired. Moreover, there is a risk of causing partial color unevenness when forming into a case shape. On the other hand, when the content of the color pigment exceeds 60% by mass, the first adhesive layer 5 becomes hard and brittle, and the adhesive force to the metal foil layer 4 may be reduced. The decrease in the adhesive force causes the heat-resistant resin layer 2 to peel off when being molded into the case shape, and causes the cohesive failure of the first adhesive layer 5.

  The colored adhesive composition is prepared by blending a color pigment and an adhesive (including a solvent and various additives) containing a two-component curable polyester urethane resin prepared by the above-described method at a predetermined ratio. The method for bonding the metal foil layer 4 and the heat resistant resin layer 2 is not limited, but a method called dry lamination can be recommended. Specifically, the prepared colored adhesive composition is applied to the upper surface of the metal foil layer 4, the lower surface of the heat-resistant resin layer 2, or both of these surfaces, and the solvent is evaporated to form a dry film. The layer 4 and the heat resistant resin layer 2 are bonded together. Thereafter, it is further cured according to the curing conditions of the two-component curable polyester urethane resin. Thereby, the metal foil layer 4 and the heat resistant resin layer 2 are joined via the first adhesive layer 5. Examples of the method for applying the colored adhesive composition include a gravure coating method, a reverse roll coating method, and a lip roll coating method.

  The thickness of the first adhesive layer 5 after curing is preferably in the range of 0.1 to 10 μm. When it is 0.1 μm or more, the color tone of the color pigment does not remain transparent, and the color and gloss of the metal foil layer 4 can be sufficiently concealed. Moreover, it can fully prevent that the 1st adhesive bond layer 5 breaks partially by maintaining favorable moldability because it is 10 micrometers or less.

(Second adhesive layer)
The second adhesive layer 6 is not particularly limited. For example, a polyurethane adhesive, an acrylic adhesive, an epoxy adhesive, a polyolefin adhesive, an elastomer adhesive, and a fluorine adhesive. And an adhesive layer formed of an acid-modified polypropylene adhesive or the like. Among these, acrylic adhesives and polyolefin adhesives are preferably used. In this case, the electrolytic solution resistance and water vapor barrier property of the packaging material 1 can be improved.

  Although the method for bonding the metal foil layer 4 and the thermoplastic resin layer 3 is not limited, the adhesive constituting the second adhesive layer is the same as the bonding of the metal foil layer 4 and the heat resistant resin layer 2 described above. An example is a dry laminating method in which the film is pasted after being applied and dried.

(Production of packaging material for molding)
The heat-resistant resin layer 2 is bonded to the upper surface of the metal foil layer 4 via the first adhesive layer 5 (colored adhesive composition) described above, and the thermoplastic resin layer 3 is bonded to the lower surface via the second adhesive layer 6. Are laminated to form a laminate. By holding at a predetermined temperature in accordance with the curing conditions of the two-component curable polyester urethane resin using this laminate, the first and second adhesive layers 5 and 6 are respectively provided on both sides of the metal foil layer 4. The heat-resistant resin layer 2 and the thermoplastic resin layer 3 are joined to produce the molding packaging material 1.

  In addition, the molding packaging material of this invention does not limit the bonding method of each layer, and the process of bonding to said method and process, The case where it produces by the other method and process is also contained in this invention.

[Other forms of packaging material for molding]
The molding packaging material of the present invention is not limited to the laminated structure shown in FIG. 1, and the function can be improved as a packaging material by adding layers. The molding packaging material 10 shown in FIG. 3 is obtained by forming chemical conversion films 11 a and 11 b on both surfaces of the metal foil layer 4. Further, the molding packaging material 20 shown in FIG. 4 is obtained by forming a mat coat layer 21 on the outer surface of the heat resistant resin layer 2 in addition to the chemical conversion films 11a and 11b.

(Chemical conversion film of metal foil layer)
The outer and inner layers of the packaging material for molding are layers made of resin. Although these resin layers are extremely small, there is a risk of light, oxygen, and liquid entering from the outside of the case, and the contents from the inside. There is a risk that the electrolyte (battery electrolyte, food, medicine, etc.) may permeate. When these intruders reach the metal foil layer, it causes corrosion of the metal foil layer. In the molding packaging material of the present invention, the metal foil layer By forming the chemical conversion films 11 a and 11 b having high corrosion resistance on the surface of 4, the corrosion resistance of the metal foil layer 4 can be improved.

The chemical conversion film is a film formed by performing a chemical conversion treatment on the surface of the metal foil, and can be formed, for example, by subjecting the metal foil to a chromate treatment or a non-chromium chemical conversion treatment using a zirconium compound. For example, in the case of chromate treatment, an aqueous solution of the mixture of any one of 1) to 3) below is applied to the surface of the metal foil that has been degreased and then dried.
1) Mixture of phosphoric acid, chromic acid, and at least one of fluoride metal salt and fluoride nonmetal salt 2) Of phosphoric acid, acrylic resin, chitosan derivative resin and phenolic resin 3) a mixture of at least one of chromic acid and chromium (III) salt, 3) phosphoric acid, one of acrylic resin, chitosan derivative resin, phenolic resin, chromic acid and chromium (III ) A mixture of at least one of the salts and at least one of a fluoride metal salt and a fluoride non-metal salt

The chemical conversion films 11a and 11b are preferably 0.1 to 50 mg / m ² , and particularly preferably ² to 20 mg / m ^{2 in} terms of chromium adhesion. Such a chemical film having a thickness or chromium adhesion amount can be used as a molding packaging material having high corrosion resistance.

  In addition, although the packaging material 10 for shaping | molding of FIG. 3 is an example which formed the chemical conversion film 11a, 11b in both surfaces of the metal foil layer 4, the packaging material which has a chemical conversion film in any one surface is also contained in this invention.

(Matte coat layer)
The mat coat layer 21 is a layer that is formed on the outer surface of the heat-resistant resin layer 2 and imparts good slipperiness to the surface of the molding packaging material 20 to improve moldability.

  The mat coat layer 21 is a mat coat layer made of a resin composition in which inorganic fine particles are dispersed and contained in a heat resistant resin component. Among them, the mat coat layer 21 is composed of a resin composition in which inorganic fine particles having an average particle diameter of 1 μm to 10 μm are contained in a two-component curable heat-resistant resin in an amount of 0.1% by mass to 1% by mass. Is preferred. Examples of the heat-resistant resin include acrylic resins, epoxy resins, polyester resins, urethane resins, polyolefin resins, and fluorine resins. Tetrahydrofuran resins are superior in terms of heat resistance and chemical resistance. It is preferable to use a fluororesin based on fluoroethylene or fluoroethylene vinyl ether. The inorganic fine particles are not particularly limited, and examples thereof include silica, alumina, calcium oxide, calcium carbonate, calcium sulfate, calcium silicate, and the like. Among these, silica is preferably used.

  The mat coat layer 21 is formed by applying a mat coat composition containing the above-described inorganic fine particles and a heat resistant resin to the surface of the heat resistant resin layer 2 and curing it.

  The thickness of the mat coat layer 21 after curing is preferably 0.5 to 5 μm. If the layer is thinner than the lower limit, the effect of improving slipperiness is small, and if the layer is thicker than the upper limit, the cost is increased. A particularly preferred thickness is in the range of 1 to 3 μm.

  The gloss value of the surface of the mat coat layer 21 is preferably set to 1% to 15% as a 60 ° reflection angle measurement value based on JIS Z8741. The gloss value is obtained, for example, by measuring at a 60 ° reflection angle with a gloss measuring device “micro-TRI-gloss-s” manufactured by BYK.

  Although the time of the process of forming the mat coat layer 21 is not limited, it is preferably performed following the process of bonding the heat resistant resin layer 2 to the metal foil layer 4 via the first adhesive layer 5.

  In addition, although the packaging material 20 for shaping | molding of FIG. 4 has shown the example which added both the chemical conversion film 11a, 11b and the mat coat layer 21 to the basic composition of FIG. 1, it does not need to equip these simultaneously, A packaging material in which only the mat coat layer 21 is added to the basic configuration of FIG. 1 is also included in the present invention.

[Molding case]
A molding case (battery case or the like) can be obtained by molding the molding packaging materials 1, 10, and 20 of the present invention (deep drawing molding, stretch molding or the like).

  Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

  In the following Examples 1 to 6 and Comparative Examples 1 to 5, the packaging materials 10 and 20 having the laminated structure shown in FIG. 3 or 4 were produced. These differ only in the composition of the first adhesive layer 5 and the presence or absence of the mat coat layer 21, and the other materials are common. Common materials are as follows.

The metal foil layer 4 is an aluminum foil 4 made of A8079 having a thickness of 40 μm, and a chemical conversion treatment solution made of polyacrylic acid, a trivalent chromium compound, water, and alcohol is applied to both sides of the aluminum foil and dried at 150 ° C. To form the chemical conversion films 11a and 11b. The amount of chromium deposited by the chemical conversion films 11a and 11b is 10 mg / m ² .

  The heat resistant resin layer 2 as the outer layer is a biaxially stretched nylon film having a thickness of 25 μm, and the thermoplastic resin layer 3 as the inner layer is an unstretched polypropylene film having a thickness of 40 μm. A polyacrylic adhesive was used for the second adhesive layer 6.

<Example 1>
First, a polyester resin (polyester polyol) which is a main component of a two-component curable polyester urethane resin is prepared. The main agent is 30 mol parts of neopentyl glycol, 30 mol parts of ethylene glycol and 40 mol parts of 1,6-hexanediol at 80 ° C., and 30 mol of adipic acid (methylene number 4) which is an aliphatic dicarboxylic acid with stirring. A polyester polyol was obtained by subjecting 70 parts by mole of isophthalic acid, which is an aromatic dicarboxylic acid, to a polycondensation reaction at 210 ° C. for 20 hours. This polyester polyol has a number average molecular weight (Mn) of 12,000, a weight average molecular weight (Mw) of 20,500, and a ratio thereof (Mw / Mn) of 1.71. Furthermore, 60 parts by mass of ethyl acetate was added to 40 parts by mass of this polyester polyol to obtain a fluid polyester polyol resin solution. The hydroxyl value was 2.2 mgKOH / g (solution value).

  Next, 13.3 parts by mass of carbon black having an average particle size of 1.0 μm, 100 parts by mass of the above polyester polyol resin solution, and 64.4 parts by mass of ethyl acetate were mixed, and then the carbon black pigment was dispersed using a pigment disperser. Thus, an adhesive main agent having a solid component content of 30% by mass and a color pigment content of 25% in the solid content was obtained. Adduct body (NCO% 13.0%) of tolylene diisocyanate (TDI) (aromatic) which is an aromatic isocyanate compound and trimethylolpropane as a curing agent with respect to 100 parts by mass of the adhesive main agent containing the color pigment. (Solid content 75%) 7.1 parts by mass and 34.1 parts by mass of ethyl acetate were further added and stirred well to obtain a colored adhesive composition.

  In the colored adhesive composition, the molar ratio (—NCO) / (— OH) of the isocyanate functional group (—NCO) to the polyester polyol hydroxyl group (—OH) is 10.

Next, the said colored adhesive composition was apply | coated to one surface of the aluminum foil 4 in which the chemical conversion films 11a and 11b were formed, and it was made to dry, and the 1st adhesive bond layer 5 was formed. The weight of the first adhesive layer 5 after drying is 4.2 g / m ² and the thickness is 4.5 μm. While the heat-resistant resin layer 2 was bonded to the first adhesive layer 5, a polyacrylic adhesive was applied as the second adhesive layer 6 to the other surface, and the thermoplastic resin layer 3 was bonded. The laminated body was allowed to stand for 5 days in a 40 ° C. environment to obtain a molding packaging material 10 shown in FIG.

<Example 2>
By using the same starting materials as in Example 1 as the main component of the colored adhesive composition constituting the first adhesive layer 5, the molecular weight is adjusted by adjusting the blending molar ratio of the total amount of diol component to the total amount of dicarboxylic acid as compared with Example 1. Different polyester polyols were prepared. The number average molecular weight (Mn) of this polyester polyol is 8,900, the weight average molecular weight (Mw) is 15,000, and Mw / Mn is 1.69. Furthermore, it shows in FIG. 3 like Example 1 except having mix | blended the molar ratio (-NCO) / (-OH) of the polyester polyol hydroxyl group (-OH) and hardening | curing agent NCO group in a coloring adhesive composition as 5. A molding packaging material 10 was obtained.

<Example 3>
As a curing agent for the colored adhesive composition forming the first adhesive layer 5, the diisocyanate component of the curing agent of Example 1 is 70 mol% of aromatic tolylene diisocyanate (TDI) and hexamethylenedi which is an aliphatic isocyanate compound. Polyfunctional isocyanate compound (NCO% 13.0%, solid content) which is an adduct of tolylene diisocyanate (TDI), hexamethylene diisocyanate (HDI) and trimethylolpropane, which is changed to 30 mol% of isocyanate (HDI) Except for the above, the molding packaging material 10 shown in FIG. 3 was obtained in the same manner as in Example 1.

<Example 4>
As an adhesive main agent containing the color pigment of the colored adhesive composition constituting the first adhesive layer 5, 4.4 parts by mass of the carbon black of Example 1, 100 parts by mass of the polyester polyol resin solution, and 43.6 parts by mass of ethyl acetate. The molding packaging material 10 shown in FIG. 3 was obtained in the same manner as in Example 1 except that the adhesive main agent was 10% in the solid content.

<Example 5>
In the colored adhesive composition constituting the first adhesive layer 5, tolylene diisocyanate (TDI) (aromatic as an aromatic isocyanate compound as a curing agent with respect to 100 parts by mass of the adhesive main component containing the color pigment of Example 1 System) and trimethylolpropane adduct (NCO% 13.0%, solid content 75%) 3.6 parts by mass, and 31 parts by mass of ethyl acetate, the molar ratio of polyester polyol hydroxyl group (-OH) ( 3 was obtained in the same manner as in Example 1 except that -NCO) / (-OH) was set to 5.

<Example 6>
For the mat coat layer 21, a mat coat composition was prepared by mixing 80 parts by mass of fluoroethylene vinyl ester as a heat resistant resin, 10 parts by mass of barium sulfate and 10 parts by mass of powdered silica as inorganic fine particles. This mat coat composition was applied to the heat resistant resin layer 2 so that the thickness after drying was 2 μm following the bonding of the heat resistant resin layer 2 in the step of Example 1. Thereafter, in the same manner as in Example 1, the molding packaging material 20 shown in FIG. 4 was obtained.

  When the gloss level of the mat coating layer 21 of the produced packaging material 20 was measured with a 60 ° reflection angle using a gloss measuring device “micro-TRI-gloss-s” manufactured by BYK, the gloss value was 1.9%. Met.

<Comparative example 1>
Polyester polyols having different molecular weights were prepared by changing the reaction conditions using the same starting materials as in Example 1 as the main component of the colored adhesive composition constituting the first adhesive layer 5. The number average molecular weight (Mn) of this polyester polyol is 6,700, the weight average molecular weight (Mw) is 8,400, and Mw / Mn is 1.25. The molding packaging shown in FIG. 3 in the same manner as in Example 1 except that the polyester polyol hydroxyl group (—OH) molar ratio (—NCO) / (— OH) was changed to 4 by using polyester polyols having different molecular weights. Material 10 was obtained.

<Comparative example 2>
As the curing agent of the colored adhesive composition forming the first adhesive layer 5, the diisocyanate component of the curing agent of Example 1 was 30 mol% of aromatic tolylene diisocyanate (TDI) and hexamethylene diene which is an aliphatic isocyanate compound. Polyfunctional isocyanate compound (NCO% 13.0%, solid content) which is an adduct of tolylene diisocyanate (TDI), hexamethylene diisocyanate (HDI) and trimethylolpropane, which has been changed to 70 mol% of isocyanate (HDI) Except for the above, the molding packaging material 10 shown in FIG. 3 was obtained in the same manner as in Example 1.

<Comparative Example 3>
As the curing agent of the colored adhesive composition forming the first adhesive layer 5, the diisocyanate component of the curing agent of Example 2 was 30 mol% of aromatic tolylene diisocyanate (TDI) and hexamethylenedi which is an aliphatic isocyanate compound. Polyfunctional isocyanate compound (NCO% 13.0%, solid content) which is an adduct of tolylene diisocyanate (TDI), hexamethylene diisocyanate (HDI) and trimethylolpropane, which has been changed to 70 mol% of isocyanate (HDI) Except for the above, the molding packaging material 10 shown in FIG. 3 was obtained in the same manner as in Example 2.

  Table 1 shows the details of the components constituting the colored adhesive composition used in each example, and shows the schematic configuration of the molding packaging material. In Table 1, the carbon black content is the carbon black content relative to the total amount of carbon black and polyester polyol.

  Each molding packaging material obtained as described above was evaluated based on the following evaluation method. The results are shown in Table 1.

<Evaluation method of appearance (color unevenness) of molded products>
For each example and each comparative example, 30 molding packaging materials were produced, and the inner thermoplastic resin layer 3 was brought into contact with the punch using a punch and a die, and the length was 50 mm × width Deep-drawing was performed into a rectangular parallelepiped shape of 35 mm × depth 5.5 mm, and a molding case having a flange portion around it was produced. In addition, all the packaging materials for molding used for deep drawing were confirmed with the naked eye that the heat-resistant resin layer 3 was not peeled off from the aluminum foil 4.

The appearance of the formed case was visually observed from the heat-resistant resin layer 2 side, and the presence or absence of color unevenness was evaluated based on the following criteria.
“○”… No color unevenness “△”… Color unevenness small “×”… Color unevenness large

<Evaluation method for the presence or absence of peeling>
For each example and each comparative example, 30 molding packaging materials were produced, and for these, the presence or absence of peeling from the aluminum foil of the heat-resistant resin layer with the naked eye, a), b), c) below. These three states were examined and evaluated based on the following criteria.

(Criteria)
“◎”: 0 of 30 heat-resistant resin layers peeled from aluminum foil “◯”: 1 or 2 of 30 heat-resistant resin layers peeled from aluminum foil "△" ... the heat-resistant resin layer peeled from the aluminum foil is 3 to 5 out of 30 "x" ... the heat-resistant resin layer peeled off the aluminum foil is 30 , 6 to 30 pieces.

  a) Molding packaging material immediately after deep drawing. That is, a packaging material for molding in which an appearance visual inspection regarding color unevenness of the molded product is performed.

  b) A flat lid was produced from the molding packaging material of the same material as the molding case of a). On the other hand, from the molded case of a), only the heat-resistant resin layer that has not been peeled is selected, and a cover material is stacked on the flange portion of the molded case that is not peeled, and heat sealing is performed at 200 ° C. × 0.3 MPa × 6 sec. went. Molding packaging material immediately after heat sealing.

  c) After selecting only the heat-resistant resin layer that did not peel off from the molding case of a), and keeping the molding case without peeling in a high-temperature and high-humidity tester of 60 ° C. × 95% RH for 72 hours. The packaging material for molding after taking out and leaving at room temperature for 5 days.

<Physical properties of cured film>
Curing of the cured film of the two-component curable polyester urethane resin adhesive (see Table 1) used in Examples 1 to 6 and Comparative Examples 1 to 3, that is, curing the composition excluding the color pigment from the composition of the first adhesive layer Films were prepared and their physical properties were evaluated.

  A two-component curable polyester urethane resin adhesive is applied to a non-adhesive untreated PP film so that the thickness after drying is 50 μm, and after the solvent is dried, 60 ° C. until the residual isocyanate becomes 5% or less. And cured by aging. The cured film was peeled from the untreated PP film and cut to a width of 15 mm was used as a test piece.

  The produced test piece was subjected to a tensile test under the conditions of a gauge distance of 50 mm and a tensile speed of 200 mm / min, and Young's modulus, breaking strength and breaking elongation were measured. The measurement results are shown in Table 1.

  Moreover, when the SS curve in this tensile test was calculated | required, Examples 1-6 were the pattern A shown in FIG.

  As is clear from Table 1, the molding packaging materials of Examples 1 to 6 of the present invention do not peel off the heat-resistant plastic resin layer even after heat-sealing the molding case after deep drawing. It hardly peels even in a hot and humid environment.

  In contrast, Comparative Example 1 using a polyol having a low molecular weight and Comparative Examples 2 and 3 using an isocyanate having a low aromatic content are peeled off in the heat-resistant resin layer in a heat seal or high temperature and high humidity environment. It was.

  The molding packaging material according to the present invention is suitably used as a battery case for notebook computers, mobile phones, in-vehicle, stationary lithium ion polymer secondary batteries and the like. Although suitable as a packaging material for pharmaceuticals, it is not particularly limited to these uses. Among these, it is particularly suitable for battery cases.

1, 10, 20 ... Packaging material for molding 2 ... Heat-resistant resin layer (outer layer)
3 ... Thermoplastic resin layer (inner layer)
4 ... Metal foil layer (aluminum foil)
5 ... 1st adhesive layer (coloring adhesive composition)
6 ... 2nd adhesive bond layer 11a, 11b ... Chemical conversion film 21 ... Matt coat layer

Claims (7)

A heat resistant resin layer as an outer layer, a thermoplastic resin layer as an inner layer, a metal foil layer disposed between both layers, and disposed between the metal foil layer and the heat resistant resin layer A molding packaging material including a first adhesive layer, and a second adhesive layer disposed between the metal foil layer and the thermoplastic resin layer,
The first adhesive layer is composed of a colored adhesive composition containing a color pigment, an adhesive containing a two-component curable polyester urethane resin with a polyester resin as a main agent and a polyfunctional isocyanate compound as a curing agent,
The polyester resin has a number average molecular weight (Mn) of 8,000 to 25,000, a weight average molecular weight (Mw) of 15,000 to 50,000, and a ratio (Mw / Mn) thereof of 1.3 to 2.5,
The molding packaging material, wherein the polyfunctional isocyanate compound contains 50 mol% or more of an aromatic isocyanate. In the two-component curable polyester urethane resin, the polyester resin as a main ingredient is a dicarboxylic acid and a dialcohol as raw materials,
The dicarboxylic acid contains an aliphatic dicarboxylic acid having an even number of methylene in the methylene chain and an aromatic dicarboxylic acid, and the content of the aromatic dicarboxylic acid with respect to the total amount thereof is 40 to 80 mol%. The molding packaging material described.   The molding packaging material according to claim 1 or 2, wherein, in the colored adhesive composition, the content of the colored pigment with respect to the total amount of the colored pigment and the polyester resin is 5 to 60% by mass.   The molded packaging material according to any one of claims 1 to 3, wherein the cured film of the two-component curable polyester urethane resin has a Young's modulus of 70 to 400 MPa according to a tensile test (JIS K7162).   The molding packaging material according to any one of claims 1 to 4, further comprising a chemical conversion film on at least one surface of the metal foil layer.   A molding case formed by deep-drawing or stretch-molding the molding packaging material according to any one of claims 1 to 5. The molded case according to claim 6, which is used as a battery case.

Images