JP7489806B2 - Composition, laminate, packaging material, battery packaging material and battery - Google Patents

Description

The present invention relates to a composition, a laminate, a packaging material, a battery packaging material, and a battery.

It has been known that a laminate containing, in this order, an aluminum foil layer as a base material, an adhesive layer, and a polypropylene layer (hereinafter also referred to as "PP layer") as an adherend (inner layer) is used as a packaging material for batteries such as lithium ion secondary batteries (battery packaging material).

As an adhesive layer in such a laminate, Patent Document 1 describes a layer obtained from an adhesive containing a polyolefin resin having a carboxyl group and a polyfunctional isocyanate compound.

JP 2010-92703 A

However, the adhesive layers obtained from conventional adhesives such as the adhesive described in Patent Document 1 did not have sufficient adhesive strength to substrates or adherends, particularly aluminum foil or polypropylene film.

Furthermore, one or two laminates containing a base material, an adhesive layer, and a PP layer in this order as described above may be thermocompressed so that the PP layers are in contact and used as a packaging material (thermocompression bonded body). However, it has been found that when an adhesive layer obtained from a conventional adhesive is used as the adhesive layer, the thickness of the PP layer cannot be maintained during the thermocompression bonding (the thickness of the portions that were the two PP layers in the thermocompression bonded body is greatly reduced from the total thickness of the two PP layers before thermocompression bonding).
If the thickness of the PP layer before thermocompression bonding cannot be maintained after thermocompression bonding (the retention rate of the PP layer decreases), the resulting thermocompression bonded body has problems such as reduced physical properties such as insulation and sealing properties, and even a poor appearance.

The present invention has been made in view of the above problems, and aims to provide an adhesive composition capable of forming an adhesive layer having excellent adhesive strength with a substrate or adherend (polypropylene layer) and capable of forming an adhesive layer that is unlikely to reduce the thickness retention rate of the polypropylene layer in contact with the adhesive layer when a thermocompression bonded body is produced by thermocompression bonding.

As a result of intensive research aimed at solving the above problems, the present inventors have found that the above object can be achieved by the following configuration examples, and have completed the present invention.
A configuration example of the present invention is as follows.

[1] A modified olefin polymer (A), which is an α-olefin polymer (a) having 2 to 20 carbon atoms modified with a polar group-containing monomer (b) and satisfies the following requirements (i) to (iii):
A curing agent (B);
1. An adhesive composition comprising:
Requirement (i): the polymer (a) contains a structural unit derived from an α-olefin having 4 to 20 carbon atoms; Requirement (ii): the heat of fusion of the olefin polymer (A), measured in accordance with JIS K 7122, is 0 J/g or more and 50 J/g or less; and Requirement (iii): the content of the structural unit derived from the monomer (b) in 100 mass% of the olefin polymer (A) is 0.7 to 3.0 mass%.

[2] The adhesive composition according to [1], which contains at least one selected from the group consisting of a synthetic hydrocarbon oil (C) having a kinetic viscosity at 40°C of 30 to 500,000 ^mm2 /s and a semi-solid hydrocarbon (D) having a kinetic viscosity at 200°C of 1,000 to 100,000 ^mm2 /s.

[3] The adhesive composition according to [1] or [2], wherein the α-olefin having 4 to 20 carbon atoms includes 1-butene.

[4] The adhesive composition according to any one of [1] to [3], wherein the polar group is a carboxyl group or an acid anhydride group.

[5] The adhesive composition according to any one of [1] to [4], wherein the curing agent (B) is a polyisocyanate.

[6] An adhesive composition comprising a base component and a curing agent component,
The main component contains the polymer (A),
The acid value of the base component is 0.9 to 5.0 mgKOH/g when the non-volatile content of the base component is 20% by mass.
The adhesive composition according to any one of [1] to [5].

[7] A laminate comprising a substrate and an adhesive layer made of a cured product of the adhesive composition described in any one of [1] to [6].

[8] A laminate including a polypropylene layer, an adhesive layer, and a substrate in this order,
The packaging material, wherein the adhesive layer is a layer made of a cured product of the adhesive composition according to any one of [1] to [6].

[9] A laminate including a polypropylene layer, an inner adhesive layer, a substrate, an outer adhesive layer, and an outer layer in this order,
A battery packing material, wherein the inner adhesive layer is a layer made of a cured product of the adhesive composition according to any one of claims 1 to 6.

[10] A battery comprising the battery packaging material described in [9] and an electrolyte solution packaged in the battery packaging material, wherein at least a portion of the polypropylene layer of the battery packaging material is in contact with the electrolyte solution.

According to the present invention, it is possible to form an adhesive layer that has excellent adhesive strength with a substrate or an adherend (PP layer), and it is possible to form an adhesive layer that is less likely to reduce the retention of the thickness of the PP layer in contact with the adhesive layer (hereinafter also referred to as "PP layer retention") when producing a thermocompression-bonded body by thermocompression bonding.
Furthermore, according to the present invention, a laminate, a packaging material, a battery packaging material, and the like, which are excellent in physical properties such as insulation and sealing property and have a good appearance, and in which a decrease in adhesive strength is sufficiently suppressed, can be easily formed, for example, by a dry lamination method.

FIG. 1 is a schematic cross-sectional view of one embodiment of a battery of the present invention.

<Adhesive composition>
The adhesive composition according to the present invention (hereinafter also referred to as "the composition") contains a modified olefin polymer (A) in which a polymer (a) of an α-olefin having 2 to 20 carbon atoms is modified with a polar group-containing monomer (b) and which satisfies the following requirements (i) to (iii), and a curing agent (B).
Requirement (i): the polymer (a) contains a structural unit derived from an α-olefin having 4 to 20 carbon atoms; Requirement (ii): the heat of fusion of the olefin polymer (A), measured in accordance with JIS K 7122, is 0 J/g or more and 50 J/g or less; and Requirement (iii): the content of the structural unit derived from the monomer (b) in 100 mass% of the olefin polymer (A) is 0.7 to 3.0 mass%.

According to the present composition, an adhesive layer having excellent adhesive strength with a substrate or an adherend (PP layer) can be formed, and an adhesive layer in which the PP layer retention rate is not easily reduced can be formed.
The reason why the adhesive layer affects the PP layer retention rate is not entirely clear, but it is speculated that when the polymer constituting the PP layer and the components constituting the adhesive layer have similar compositions, they are compatible with each other, and the components contained in the adhesive layer lower the softening point of the PP layer.
Since the present composition contains the specific modified olefin polymer (A) and the curing agent (B), it is believed that an adhesive layer can be formed that has excellent adhesive strength with a PP layer while being less likely to lower the softening point of the PP layer, and therefore is less likely to lower the PP layer retention rate.

The present composition may be a one-component composition or a multi-component composition having two or more components. However, for example, when the polar group is a functional group reactive to the curing agent (B), the present composition is preferably a multi-component composition containing a main component containing a polymer (A) and a curing agent component containing a curing agent (B) from the viewpoint of excellent storage stability, etc.
When the present composition is such a multi-component composition, for example, when it is a composition consisting of the base component and the hardener component, the composition can also be said to be a kit containing the base component and the hardener component.
In the case of a multi-component composition, these components are usually stored, preserved, transported, etc. in separate containers, and are mixed together immediately before use.

From the viewpoints of ease of preparation of the composition and improvement of processability, it is preferable that the main component containing the polymer (A) contains a solvent and/or a dispersion medium, and it is more preferable that the solvent and/or dispersion medium is a solvent capable of dissolving the polymer (A).
The solvent may be the same as that which can be used in the synthesis of the polymer (A) described below, and preferably includes toluene, a mixed solvent of methylcyclohexane/methyl isobutyl ketone, a mixed solvent of methylcyclohexane/methyl ethyl ketone, a mixed solvent of methylcyclohexane/ethyl acetate, a mixed solvent of cyclohexane/methyl ethyl ketone, a mixed solvent of cyclohexane/ethyl acetate, and a mixed solvent of cellosolve/cyclohexanone. Water may also be used as the dispersion medium.

It is desirable to blend the solvent and dispersion medium so that the non-volatile content in 100% by mass of the main agent is, for example, 5% by mass or more, preferably 10% by mass or more, and, for example, 50% by mass or less, preferably 40% by mass or less.
In the present invention, the non-volatile content refers to the amount of components other than the solvent and the dispersion medium.

When the non-volatile content of the main component is 20 mass %, the main component desirably has an acid value of preferably 0.9 mg KOH/g or more, more preferably 1.0 mg KOH/g or more, and preferably 5.0 mg KOH/g or less, more preferably 4.0 mg KOH/g or less.
When the acid value of the base component is within the above range, the base component and the curing agent component can be reacted efficiently, and an adhesive layer that is less likely to reduce the PP layer retention rate can be easily obtained. On the other hand, when the acid value of the base component exceeds the above upper limit, the pot life after mixing with the curing agent component becomes short, and workability may become poor.
Specifically, the acid value of the main component can be measured by the method described in the examples below.

<Modified Olefin Polymer (A)>
The polymer (A) satisfies the above requirements (i) to (iii) and is a modified product obtained by modifying a polymer (a) of an α-olefin having 2 to 20 carbon atoms with a polar group-containing monomer (b).
The polymer (A) may be used alone or in combination of two or more.

The content of polymer (A) in the present composition is preferably 50% by mass or more, more preferably 60% by mass or more, and is preferably 99% by mass or less, more preferably 97% by mass or less, based on 100% by mass of the non-volatile content of the present composition.
When the content of the polymer (A) is within the above range, an adhesive layer having excellent adhesive strength and chemical resistance (electrolyte resistance) can be easily obtained.

The weight average molecular weight (Mw) of the polymer (A), measured by gel permeation chromatography (GPC) and converted into standard polystyrene, is preferably 1 × 10 ⁴ or more, more preferably 2 × 10 ⁴ or more, particularly preferably 3 × 10 ⁴ or more, and is preferably 1 × 10 ⁷ or less, more preferably 1 × 10 ⁶ or less, particularly preferably 5 × 10 ⁵ or less.
When the Mw of the polymer (A) is within the above range, it tends to be easy to form an adhesive layer that does not easily reduce the PP layer retention rate. When the Mw of the polymer (A) satisfies the lower limit, it is easy to obtain an adhesive layer that is sufficiently strong and has excellent adhesive strength with the substrate or adherend (PP layer), and when it satisfies the upper limit, it is easy to obtain a polymer (A) that has good solubility in a solvent and is unlikely to solidify or precipitate. In particular, when the Mw of the polymer (A) is 5 x 10 ⁵ or less, it is easy to obtain an adhesive layer that has excellent adhesive strength with the substrate or adherend (PP layer).

The molecular weight distribution (Mw/Mn) of the polymer (A) is preferably 1 or more, more preferably 1.5 or more, and is preferably 3 or less, more preferably 2.5 or less.
When the Mw/Mn ratio satisfies the lower limit, a polymer (A) having good solubility in a solvent and being less susceptible to solidification and precipitation can be easily obtained. When the Mw/Mn ratio satisfies the upper limit, an adhesive layer having sufficiently high strength and excellent adhesive strength to a substrate or an adherend (PP layer) can be easily obtained.
In the present invention, specifically, Mw and Mw/Mn can be measured by a method similar to that described in the following examples.

The melting point (Tm) of the polymer (A) is preferably less than 120°C, more preferably less than 100°C, even more preferably 95°C or less, particularly preferably 90°C or less, and is preferably 40°C or more, more preferably 50°C or more.
When the Tm of polymer (A) satisfies the upper limit specified above, it becomes easy to suppress a decrease in adhesive strength even when an adhesive layer is formed from this composition under low-temperature curing conditions, and when the Tm of polymer (A) satisfies the lower limit specified above, an adhesive layer excellent in strength and durability can be easily obtained.
Polymer (A) having the above Tm can be obtained, for example, by adjusting the content of structural units derived from an α-olefin having 2 to 3 carbon atoms in polymer (A) to the same range as the content of structural units derived from an α-olefin having 2 to 3 carbon atoms described in the column for polymer (a) below, and by satisfying requirement (i).

In the present invention, Tm is determined by differential scanning calorimetry (DSC measurement) in accordance with JIS K 7122. Specifically, the temperature is raised from 30°C to 180°C at 10°C/min, held at that temperature for 3 minutes, then lowered to 0°C at 10°C/min, held at that temperature for 3 minutes, and then raised again to 150°C at 10°C/min. During this process, Tm is determined in accordance with JIS K 7122 from the thermogram obtained during the second temperature rise.

The heat of fusion (ΔH) of the polymer (A) is 0 J/g or more, preferably 3 J/g or more, more preferably 5 J/g or more, and is 50 J/g or less, preferably 40 J/g or less, more preferably 35 J/g or less.
When the ΔH of the polymer (A) satisfies the upper limit specification, an adhesive layer having excellent adhesive strength can be easily obtained even when an adhesive layer is formed from the composition under low temperature curing conditions, and when the ΔH satisfies the lower limit specification, an adhesive layer having excellent strength can be easily obtained.
If the ΔH of the polymer (A) exceeds 50 J/g, the resulting polymer (A) will have poor solubility in a solvent and will be prone to solidification and precipitation.
Polymer (A) having the above ΔH can be obtained, for example, by adjusting the content of constitutional units derived from an α-olefin having 2 to 3 carbon atoms in polymer (A) to the same range as the content of constitutional units derived from an α-olefin having 2 to 3 carbon atoms described in the column for polymer (a) below, and by satisfying requirement (i).

In the present invention, ΔH is determined by differential scanning calorimetry (DSC measurement) in accordance with JIS K 7122, and specifically, is calculated from the peak area of the thermogram obtained during the heating process at 10°C/min. More specifically, in order to cancel the thermal history before the measurement, the temperature is raised to 180°C at 10°C/min before the measurement, held at that temperature for 3 minutes, then lowered to 0°C at 10°C/min, held at that temperature for 3 minutes, and then ΔH is measured.

The crystallization half time of the polymer (A) at 50° C. is preferably 100 seconds or more, more preferably 150 seconds or more, and even more preferably 200 seconds or more. The crystallization half time also includes the case where crystallization does not substantially occur or where the value of the crystallization half time is too large to be calculated, i.e., the crystallization half time is infinite.
When the semi-crystallization time of the polymer (A) satisfies the above-mentioned lower limit, the polymer (A) can react with the curing agent (B) while penetrating into the irregularities on the surface of the substrate or adherend (PP layer) or after penetrating therein, and the adhesive strength of the resulting adhesive layer can be further improved by the anchor effect.

The crystallization half time can be determined by isothermal crystallization measurement using a differential scanning calorimeter, and specifically, can be determined by the following method.
About 5 mg of polymer (A) is packed in a dedicated aluminum pan, and using a differential scanning calorimeter, the temperature is increased from 30° C. to 150° C. at 320° C./min, held at 150° C. for 5 minutes, and then decreased at 320° C./min to 50° C., and the DSC curve obtained when held at that temperature is analyzed. Specifically, the total heat amount is calculated from the area between the DSC heat curve and the baseline, and the time when 50° C. is reached is taken as the reference (t=0), and the time when 50% of the calculated total heat amount is reached is taken as the half-crystallization time.

The kinetic viscosity of the polymer (A) at 40° C. is preferably more than 500,000 mm ² /s. When the kinetic viscosity exceeds 500,000 mm ² /s, the fluidity is low and the kinetic viscosity may not be measurable.
In the present invention, the kinematic viscosity is measured based on ASTM D 445.

The content (modification amount) of the structural unit derived from the monomer (b) in 100 mass% of the polymer (A) is 0.7 mass% or more, preferably 0.8 mass% or more, and 3.0 mass% or less, preferably 2.5 mass% or less.
When the amount of modification is within the above range, the polymer (A) reacts efficiently when forming the adhesive layer, and the affinity of the polymer (A) to the substrate or PP layer is increased, and the adhesive strength between the adhesive layer and the substrate or PP layer can be further improved, while the adhesive layer that does not easily reduce the PP layer retention tends to be easily formed. Also, the chemical resistance and electrolyte resistance of the obtained adhesive layer can be improved.

The degree of modification in the present invention can be measured by ¹ H-NMR, specifically, under the following conditions.
Specifically, the following conditions were used: an ECX400 nuclear magnetic resonance spectrometer (manufactured by JEOL Ltd.), deuterated orthodichlorobenzene was used as the solvent, the sample concentration was 20 mg/0.6 mL, the measurement temperature was 120° C., the observation nucleus was ^1H (400 MHz), the sequence was a single pulse, the pulse width was 5.12 μsec (45° pulse), the repetition time was 7.0 sec, and the number of accumulations was 500 or more.
The reference chemical shift is set to 0 ppm for the peak derived from hydrogen in tetramethylsilane, but similar results can be obtained by setting, for example, the peak derived from residual hydrogen in deuterated orthodichlorobenzene to 7.10 ppm.
Peaks such as ¹ H derived from the monomer (b) can be assigned by a conventional method.

When unsaturated carboxylic acids and acid anhydrides are used as monomer (b), it is also possible to use, for example, the acid value as an indicator of the amount of functional groups introduced into polymer (A).

[Polymer (a) of α-olefin having 2 to 20 carbon atoms]
The polymer (a) is not particularly limited as long as it contains a structural unit derived from an α-olefin having 4 to 20 carbon atoms, and may be a polymer made of an α-olefin having 4 to 20 carbon atoms, or a copolymer obtained by using an α-olefin having 4 to 20 carbon atoms and an α-olefin having 2 to 3 carbon atoms, or may be a polymer containing a structural unit derived from an unsaturated monomer other than an α-olefin (hereinafter also referred to as "other unsaturated monomer").
When the polymer (a) does not have a structural unit derived from an α-olefin having 4 to 20 carbon atoms, the long-term stability of a composition containing the polymer and a solvent decreases, and it becomes difficult to simultaneously achieve excellent adhesive strength and suppress a decrease in the retention rate of the PP layer.

The α-olefin used as the raw material for the polymer (a) may be one type alone or two or more types. Specifically, it may be a homopolymer or copolymer of an α-olefin having 4 to 20 carbon atoms, or it may be a copolymer (a1) of one or more α-olefins having 4 to 20 carbon atoms and one or more α-olefins having 2 to 3 carbon atoms.
The copolymer may be, for example, a random copolymer or a block copolymer, with a random copolymer being preferred.

Examples of the α-olefins having 4 to 20 carbon atoms include linear or branched α-olefins such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

The α-olefin having 4 to 20 carbon atoms is preferably a linear olefin having 4 to 10 carbon atoms, more preferably a linear olefin having 4 to 6 carbon atoms, in terms of obtaining a polymer having excellent solubility in solvents and strength, and further preferably contains 1-butene, in terms of obtaining a polymer having particularly excellent effects as described above, and particularly preferably is 1-butene.

Examples of the α-olefins having 2 to 3 carbon atoms include ethylene and propylene.

Examples of the other unsaturated monomers include conjugated polyenes such as butadiene and isoprene, and non-conjugated polyenes such as 1,4-hexadiene, 1,7-octadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 5-methylene-2-norbornene, and 2,5-norbornadiene.

The copolymer (a1) is preferred as the polymer (a) because it is easy to obtain a polymer with excellent solubility in solvents and strength, and a copolymer of ethylene or propylene and an α-olefin having 4 to 20 carbon atoms is more preferred, and a copolymer in which all of the structural units except for those derived from ethylene or propylene are structural units derived from the α-olefin having 4 to 20 carbon atoms is more preferred, and it is even more preferred that the α-olefin having 4 to 20 carbon atoms contains 1-butene, and a copolymer of 1-butene and propylene or ethylene is particularly preferred.

In the polymer (a), when the α-olefin having 2 to 3 carbon atoms is propylene, the content of the structural units derived from an α-olefin having 4 to 20 carbon atoms is, relative to 100 mol% of the structural units derived from an α-olefin having 2 to 20 carbon atoms, preferably relative to 100 mol% of all structural units constituting the polymer (a), for example, 5 mol% or more, preferably 10 mol% or more, more preferably 20 mol% or more, and for example, 100 mol% or less, preferably 60 mol% or less, more preferably 50 mol% or less, even more preferably 40 mol% or less, and particularly preferably 35 mol% or less.
In addition, in the polymer (a), when the α-olefin having 2 to 3 carbon atoms is ethylene, the content of the structural units derived from an α-olefin having 4 to 20 carbon atoms is, relative to 100 mol% of the structural units derived from an α-olefin having 2 to 20 carbon atoms, preferably relative to 100 mol% of all structural units constituting the polymer (a), is, for example, 50 mol% or more, preferably 70 mol% or more, more preferably 90 mol% or more, and for example, 100 mol% or less, preferably 99.8 mol% or less, more preferably 99.5 mol% or less, even more preferably 99 mol% or less, and particularly preferably 98.8 mol% or less.
When the content of the structural units derived from an α-olefin having 4 to 20 carbon atoms satisfies the upper limit specified above, a polymer having superior strength can be easily obtained, and when the content of the structural units derived from an α-olefin having 4 to 20 carbon atoms satisfies the lower limit specified above, a polymer having superior solubility in a solvent can be easily obtained.

In the polymer (a), when the α-olefin having 2 to 3 carbon atoms is propylene, the content of the structural units derived from an α-olefin having 2 to 3 carbon atoms is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, particularly preferably 65 mol% or more, relative to 100 mol% of the structural units derived from an α-olefin having 2 to 20 carbon atoms, preferably relative to 100 mol% of all structural units constituting the polymer (a), and is preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 85 mol% or less, particularly preferably 80 mol% or less.
In addition, in the polymer (a), when the α-olefin having 2 to 3 carbon atoms is ethylene, the content of the structural units derived from an α-olefin having 2 to 3 carbon atoms is preferably 0.2 mol% or more, more preferably 0.5 mol% or more, even more preferably 1 mol% or more, and particularly preferably 1.2 mol% or more, relative to 100 mol% of the structural units derived from an α-olefin having 2 to 20 carbon atoms, and preferably relative to 100 mol% of all structural units constituting the polymer (a), and is also preferably 50 mol% or less, more preferably 30 mol% or less, and even more preferably 10 mol% or less.
When the content of the structural units derived from an α-olefin having 2 to 3 carbon atoms satisfies the upper limit specified above, the melting point (Tm) and heat of fusion (ΔH) of the copolymer can be reduced, and when the content of the structural units derived from an α-olefin having 2 to 3 carbon atoms satisfies the lower limit specified above, a polymer having superior strength can be obtained.

The polymer (a) can be obtained by polymerizing an α-olefin having 2 to 20 carbon atoms in the presence of a known solid Ti catalyst or metallocene catalyst that is commonly used in the production of α-olefin polymers. Examples of the metallocene catalyst include catalysts containing a metallocene compound such as rac-dimethylsilylene-bis{1-(2-methyl-4-phenylindenyl)}zirconium dichloride, an organoaluminum oxy compound such as methylaluminoxane, and an organoaluminum compound such as triisobutylaluminum. More specifically, the polymer (a) can be obtained by, for example, the method described in International Publication No. WO 2004/87775.

The Mw of the polymer (a) measured by GPC and calculated based on standard polystyrene is preferably 1×10 ⁴ or more and preferably 1×10 ⁷ or less, and the Mw/Mn is preferably 1 or more and preferably 3 or less.
When the Mw or Mw/Mn satisfies the above-mentioned lower limit specifications, an adhesive layer having sufficiently high strength can be easily obtained, and the adhesive strength between the adhesive layer and the substrate or adherend (PP layer) becomes good. When the Mw or Mw/Mn satisfies the above-mentioned upper limit specifications, a polymer having good solubility in solvents can be obtained, and a composition which is less likely to solidify or precipitate can be easily obtained.

The Tm of the polymer (a) is preferably less than 120°C, more preferably less than 100°C.
When Tm is within the above range, an adhesive layer having excellent adhesive strength can be easily obtained even when the adhesive layer is formed from the present composition under low-temperature curing conditions.

The ΔH of the polymer (a) is preferably 0 J/g or more, more preferably 3 J/g or more, particularly preferably 5 J/g or more, and is preferably 50 J/g or less, more preferably 40 J/g or less.
When ΔH satisfies the upper limit specification, an adhesive layer having excellent adhesive strength can be easily obtained even when an adhesive layer is formed from this composition under low temperature curing conditions, and when ΔH satisfies the lower limit specification, an adhesive layer having excellent strength can be easily obtained.

[Polar group-containing monomer (b)]
The monomer (b) is not particularly limited as long as it has a polar group, and any conventionally known compound can be used.

The polar group is preferably a functional group reactive with the curing agent (B).
When the curing agent (B) is a compound containing an isocyanate group, the polar group may be a functional group reactive to an isocyanate group, such as a group having an active hydrogen, and specific examples of the polar group include a hydroxyl group, an amino group, an epoxy group, a carboxyl group, and an acid anhydride group.
When the curing agent (B) is a compound containing an epoxy group or an oxazoline group, the polar group may be a functional group reactive to the epoxy group or the oxazoline group, such as a group having active hydrogen. Specific examples of the polar group include a hydroxyl group, an amino group, a carboxyl group, an acid anhydride group, an ester group, and a thiol group.
The monomer (b) may have one type of reactive functional group, or may have two or more types of reactive functional groups.

As the monomer (b), a monomer (b) having an acid anhydride group or a carboxyl group is preferred because it reacts efficiently when forming the adhesive layer, increasing the affinity of the polymer (A) with the substrate (e.g. aluminum foil) or adherend (PP layer), thereby further improving the adhesive strength between the adhesive layer and the substrate or adherend (PP layer), and it also tends to be easy to form an adhesive layer that does not easily reduce the PP layer retention rate.

Examples of monomer (b) include hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, epoxy group-containing unsaturated compounds, unsaturated carboxylic acids, unsaturated carboxylic anhydrides, vinyl ester compounds, thiol group-containing unsaturated compounds, and derivatives thereof.

Examples of the hydroxyl group-containing unsaturated compounds include hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxy-propyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, glycerin mono(meth)acrylate, pentaerythritol mono(meth)acrylate, trimethylolpropane mono(meth)acrylate, tetramethylolethane mono(meth)acrylate, butanediol mono(meth)acrylate, and the like. Examples of such hydroxyl group-containing (meth)acrylic acid esters include acrylate, polyethylene glycol mono(meth)acrylate, 2-(6-hydrohexanoyloxy)ethyl acrylate, and 2-(meth)acryloyloxyethyl acid phosphate; 10-undecen-1-ol, 1-octene-3-ol, 2-methanol norbornene, hydroxystyrene, N-methylolacrylamide, glycerin monoallyl ether, allyl alcohol, allyloxyethanol, 2-butene-1,4-diol, and glycerin monoalcohol.

The amino group-containing unsaturated compound may, for example, be a vinyl monomer having at least one type of amino group or substituted amino group represented by --NHR ¹ .
Examples of R ¹ include a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, or a cycloalkyl group having 8 to 12 carbon atoms, preferably 6 to 9 carbon atoms. Examples of R ¹ include groups in which the alkyl group and cycloalkyl group are partially substituted with a substituent.

Examples of the amino group-containing unsaturated compound include aminomethyl (meth)acrylate, aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, propylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, phenylaminomethyl (meth)acrylate, cyclohexylaminoethyl (meth)acrylate, N-vinyldiethylamine, N-acetylvinylamine, (meth)acrylamide, N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, p-aminohexylsuccinimide, and 2-aminoethylsuccinimide.

The epoxy group-containing unsaturated compound may, for example, be a compound having at least one polymerizable unsaturated bond group and at least one epoxy group in one molecule.
Examples of such epoxy group-containing ethylenically unsaturated compounds include glycidyl esters of unsaturated carboxylic acids such as glycidyl (meth)acrylate, monoesters of unsaturated dicarboxylic acids such as maleic acid, fumaric acid, crotonic acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, endo-cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (Nadic acid TM), and endo-cis-bicyclo[2.2.1]hept-5-ene-2-methyl-2,3-dicarboxylic acid (methyl Nadic acid TM). Examples of such glycidyl esters include glycidyl esters (wherein the alkyl group in the case of monoglycidyl esters has 1 to 12 carbon atoms), alkyl glycidyl esters of p-styrene carboxylic acid, allyl glycidyl ether, 2-methylallyl glycidyl ether, styrene-p-glycidyl ether, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, 3,4-epoxy-1-pentene, 3,4-epoxy-3-methyl-1-pentene, 5,6-epoxy-1-hexene, and vinylcyclohexene monoxide.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, norbornene dicarboxylic acid, and bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic acid.

Examples of the unsaturated carboxylic acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic anhydride.

Examples of the vinyl ester compounds include vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl versatate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl salicylate, and vinyl cyclohexanecarboxylate.

Examples of the thiol group-containing unsaturated compounds include thiophenol derivatives such as allyl mercaptan, 2-vinylbenzyl mercaptan, 3-vinylbenzyl mercaptan, 4-vinylbenzyl mercaptan, and vinylthiophenol.

Examples of the derivatives include malenyl chloride, malenylimide, dimethyl maleate, monomethyl maleate, diethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconate, dimethyl tetrahydrophthalate, and dimethyl bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylate.

As the monomer (b), unsaturated carboxylic acids and unsaturated carboxylic anhydrides are preferred, unsaturated carboxylic anhydrides are more preferred, and maleic anhydride is even more preferred, from the viewpoints that they react efficiently when forming the adhesive layer, increase the affinity of the polymer (A) with the substrate or adherend (PP layer), and can further improve the adhesive strength between the adhesive layer and the substrate or adherend (PP layer), and they also tend to easily form an adhesive layer that is less likely to reduce the PP layer retention rate.

[Method for synthesizing modified olefin polymer (A)]
The method for synthesizing the polymer (A) is not particularly limited, and may be a polymerization reaction between an α-olefin having 2 to 20 carbon atoms and the monomer (b). However, it is preferable to react the monomer (b) with the polymer (a). Specific examples of the method include the following methods (1) to (4).

(1) A method in which the polymer (a) is dissolved in a solvent, the monomer (b) and a radical polymerization initiator are added, and the mixture is heated and stirred to react the polymer (a) with the monomer (b).
(2) A method in which the polymer (a) is heated and melted, and the monomer (b) and a radical polymerization initiator are added to the resulting melt and stirred, thereby reacting the polymer (a) with the monomer (b).
(3) A method in which the polymer (a), the monomer (b) and a radical polymerization initiator are mixed, and the resulting mixture is fed into an extruder and heated and kneaded while reacting the polymer (a) with the monomer (b).
(4) A method in which the polymer (a) is immersed in a solution in which the monomer (b) and a radical polymerization initiator are dissolved in an organic solvent, and then the solution is heated to a temperature at which the polymer (a) does not dissolve, thereby reacting the polymer (a) with the monomer (b).

The polymer (a) and the monomer (b) used in the reaction may each be used alone or in combination of two or more kinds.
In addition, during the reaction, a monomer not having a polar group may be used together with the monomer (b). However, it is preferable not to use a monomer not having a polar group, because a polymer (A) capable of efficiently reacting with the curing agent (B) can be obtained, and the chemical resistance and electrolyte resistance of the resulting adhesive layer can be improved.

The amount of monomer (b) is preferably such that the content (modification amount) of the structural unit derived from monomer (b) in polymer (A) is within the above range, and is preferably 0.7% by mass or more, more preferably 1.0% by mass or more, and is preferably 15% by mass or less, more preferably 12% by mass or less, relative to 100% by mass of the total amount of polymer (a) and monomer (b).

The reaction temperature is, for example, 50°C or higher, preferably 80°C or higher, and is, for example, 300°C or lower, and the reaction time is, for example, about 1 minute to 10 hours.

The reaction method for the reaction may be a batch method or a continuous method, and the batch method is preferred in order to carry out the modification reaction uniformly.

Examples of the radical polymerization initiator include organic peroxides and organic peresters.
Examples of organic peroxides include dicumyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxybenzoate)hexyne-3, 1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.
Examples of organic peresters include tert-butyl peracetate, tert-butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butyl persec-octoate, tert-butyl perpivalate, cumyl perpivalate, tert-butyl perdiethyl acetate, and tert-butyl peroxybenzoate.
Further, examples of the radical polymerization initiator include other initiators such as azo compounds such as azobisisobutyronitrile and dimethylazoisobutyronitrile.

Among radical polymerization initiators, organic peroxides are preferred, and dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 1,4-bis(tert-butylperoxyisopropyl)benzene, etc. are more preferred.

The mixing ratio of the radical polymerization initiator is, for example, 0.001 parts by mass or more and 10 parts by mass or less per 100 parts by mass of polymer (a).

The synthesis of the polymer (A) may be carried out in the presence of one or more solvents.
Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as hexane, heptane, octane, and decane, alicyclic hydrocarbons such as cyclohexane, cyclohexene, and methylcyclohexane, alcohols such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol, ketones such as acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, isophorone, acetophenone, and cyclohexanone, cellosolves such as methyl cellosolve and ethyl cellosolve, esters such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and butyl formate, and halogenated hydrocarbons such as trichloroethylene, dichloroethylene, and chlorobenzene. Among these, aromatic hydrocarbons, aliphatic hydrocarbons, mixed solvents of aliphatic hydrocarbons and ketones, and mixed solvents of aliphatic hydrocarbons and esters are preferred.

When polymer (A) is synthesized in the presence of a solvent, the resulting solution (varnish) containing polymer (A) may be used as is in the preparation of the present composition, may be used as the main component as is, or polymer (A) may be extracted from the varnish and used in the preparation of the present composition.

<Curing Agent (B)>
The curing agent (B) is a compound different from the polymer (A) and is preferably a component capable of curing the polymer (A). Specific examples of the curing agent (B) include an isocyanate compound, an epoxy compound, and an oxazoline compound. Among these, an isocyanate compound is preferable.
The curing agent (B) may be used alone or in combination of two or more kinds.

It is desirable to blend the curing agent (B) so that the functional group equivalent in the curing agent (B)/the polar group equivalent in the polymer (A) is preferably 0.01 or more, more preferably 0.1 or more, and is preferably 50 or less, more preferably 30 or less, even more preferably 20 or less, and particularly preferably 10 or less.
When the blending amount of the curing agent (B) is within the above range, an adhesive layer having superior adhesive strength, chemical resistance, and electrolyte resistance can be obtained.

The isocyanate compound is preferably a polyisocyanate having two or more isocyanate groups, and examples of such polyisocyanates include polyisocyanate monomers and modified polyisocyanates.

Examples of the polyisocyanate monomer include aromatic polyisocyanates, araliphatic polyisocyanates, and aliphatic polyisocyanates.

Examples of the aromatic polyisocyanate include aromatic diisocyanates such as tolylene diisocyanate (2,4- or 2,6-tolylene diisocyanate or a mixture thereof) (TDI), phenylene diisocyanate (m-, p-phenylene diisocyanate or a mixture thereof), 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), methylene diphenyl diisocyanate (4,4'-, 2,4'-, or 2,2'-methylene diphenyl diisocyanate or a mixture thereof) (MDI), 4,4'-toluidine diisocyanate (TODI), and 4,4'-diphenyl ether diisocyanate.

Examples of the aromatic aliphatic polyisocyanate include aromatic aliphatic diisocyanates such as xylylene diisocyanate (1,3- or 1,4-xylylene diisocyanate or a mixture thereof) (XDI), tetramethyl xylylene diisocyanate (1,3- or 1,4-tetramethyl xylylene diisocyanate or a mixture thereof) (TMXDI), and ω,ω'-diisocyanato-1,4-diethylbenzene.

Examples of the aliphatic polyisocyanate include aliphatic diisocyanates such as trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate), 1,5-pentamethylene diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI), 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methylcaprate.

The aliphatic polyisocyanate also includes alicyclic polyisocyanates. Examples of the alicyclic polyisocyanates include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate [isophorodiisocyanate] (IPDI), methylene bis(cyclohexyl isocyanate) [4,4'-, 2,4'-, or 2,2'-methylene bis(cyclohexyl isocyanate), their trans-trans isomer, trans-cis isomer, cis-cis isomer, or a mixture thereof] (H ₁₂ alicyclic diisocyanates such as methylcyclohexane diisocyanate (methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate), norbornane diisocyanate (various isomers or mixtures thereof) (NBDI), and bis(isocyanatomethyl)cyclohexane [1,3- or 1,4-bis(isocyanatomethyl)cyclohexane or mixtures thereof] (H ₆ XDI).

The polyisocyanate modified product has an average functional group number exceeding 2, and may be, for example, a multimer of the polyisocyanate monomer (e.g., a dimer, a trimer (e.g., an isocyanurate modified product, an iminooxadiazinedione modified product), a pentamer, or a heptamer), an allophanate modified product (e.g., an allophanate modified product produced by the reaction of the polyisocyanate monomer with a monool (e.g., octadecanol), a polyol modified product (e.g., a polyol modified product (alcohol adduct) produced by the reaction of the polyisocyanate monomer with a low molecular weight polyol (e.g., a trihydric alcohol)), or a biuret modified product (e.g., a polyisocyanate monomer with a low molecular weight polyol (e.g., a trihydric alcohol)). biuret modified products produced by the reaction of the polyisocyanate monomer with water or amines), urea modified products (e.g., urea modified products produced by the reaction of the polyisocyanate monomer with a diamine), oxadiazinetrione modified products (e.g., oxadiazinetrione produced by the reaction of the polyisocyanate monomer with carbon dioxide), carbodiimide modified products (e.g., carbodiimide modified products produced by the decarboxylation condensation reaction of the polyisocyanate monomer), uretdione modified products, uretonimine modified products, and polymethylene polyphenyl polyisocyanate (crude MDI, polymeric MDI).

The epoxy compound is preferably a crosslinkable compound having two or more epoxy groups in one molecule. Examples of such epoxy compounds include bisphenol type epoxy resins such as bisphenol A type epoxy resins (different from hydrogenated bisphenol A type epoxy resins) and bisphenol F type epoxy resins; hydrogenated bisphenol type epoxy resins; novolac type epoxy resins; biphenyl type epoxy resins; stilbene type epoxy resins; hydroquinone type epoxy resins; naphthalene skeleton type epoxy resins; tetraphenylolethane type epoxy resins; trishydroxyphenylmethane type epoxy resins; dicyclopentadiene phenol type epoxy resins; alicyclic epoxy resins such as 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol; polybasic acid polyethers such as diglycidyl ester of hexahydrophthalic anhydride. Glycidyl esters; glycidyl ethers such as sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, polypropylene glycol diglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, and cyclohexanedimethanol diglycidyl ether; diene polymer type epoxy resins such as polybutadiene or polyisoprene; glycidyl amine type epoxy resins such as tetraglycidyldiaminodiphenylmethane, tetraglycidylbisaminomethylcyclohexane, diglycidylaniline, and tetraglycidylmetaxylylenediamine; heterocyclic ring-containing epoxy resins such as triazine or hydantoin.

Among the above epoxy compounds, bisphenol A type liquid epoxy resins, alicyclic epoxy compounds, and trimethylolpropane polyglycidyl ether are preferred because they have superior adhesive strength, and in particular, they can provide an adhesive layer that can bond the aluminum foil and the PP layer with higher strength.

The bisphenol A type liquid epoxy resin is not particularly limited as long as it is a resin that is liquid at room temperature (25° C.), and a commercially available product may be used.
Examples of commercially available products include EPICLON 840, 840-S, 850, 850-S, EXA-850CRP, and 850-LC (manufactured by DIC Corporation), jER828EL and 827 (manufactured by Mitsubishi Chemical Corporation), and Epomic R-140P (manufactured by Mitsui Chemicals, Inc.).

Examples of the alicyclic epoxy compound include a compound having at least one epoxycycloalkyl group or epoxycycloalkenyl group in the molecule, or a compound having at least one group in which at least one epoxy group is bonded to an alicyclic ring by a single bond in the molecule.

Examples of the alicyclic epoxy compounds include 3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexene carboxylate, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, 3,4-epoxycyclohexyl octyl-3,4-epoxycyclohexane carboxylate, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-m-dioxane, bis(3,4-epoxycyclohexylmethyl)adipate, vinylcyclohexene dioxide, bis(3,4-epoxy-6-methylcyclohexyl methyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3,4-epoxy-6-methylcyclohexane carboxylate, methylene bis(3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylene glycol di(3,4-epoxycyclohexylmethyl) ether, ethylene bis(3,4-epoxycyclohexane carboxylate), 1,2,8,9-diepoxylimonene, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, and compounds described in JP 2008-214555 A.

As the alicyclic epoxy compound, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate is preferred, since it is possible to obtain an adhesive layer with superior adhesive strength.

Examples of the trimethylolpropane polyglycidyl ether include trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, and mixtures thereof.

The oxazoline compound is preferably a crosslinkable compound having two or more oxazoline groups in one molecule. Examples of such oxazoline compounds include oxazoline group-containing polymers such as polymers of oxazoline group-containing monomers and copolymers of oxazoline group-containing monomers and other monomers.

Examples of the oxazoline group-containing monomer include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, 2-isopropenyl-2-oxazoline, and 2-isopropenyl-4,4-dimethyl-2-oxazoline.

Examples of the other monomers include alkyl (meth)acrylates (alkyl groups having about 1 to 14 carbon atoms); unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid and their salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile and methacrylonitrile; (meth)acrylamide, N-alkyl (meth)acrylamide, N,N-dialkyl (meth)acrylamide, (alkyl group: methyl group unsaturated amides such as ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogen-containing α,β-unsaturated monomers such as vinyl chloride, vinylidene chloride, and vinyl fluoride; and α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene.

As the oxazoline compound, an oxazoline compound containing 2-isopropenyl-2-oxazoline is preferred, since it is possible to obtain an adhesive layer with superior adhesive strength.

<Hydrocarbon Synthetic Oil (C) and Semi-Solid Hydrocarbon (D)>
The present composition may further contain at least one selected from the group consisting of a hydrocarbon synthetic oil (C) and a semi-solid hydrocarbon (D) in addition to the above components, from the viewpoint of being able to obtain an adhesive layer with high adhesive strength, etc. Of these, the hydrocarbon synthetic oil (C) is preferred, and the present composition preferably contains the hydrocarbon synthetic oil (C).
The synthetic hydrocarbon oil (C) may be used alone or in combination of two or more. The semi-solid hydrocarbon (D) may be used alone or in combination of two or more.

Examples of the hydrocarbon synthetic oil (C) and the semi-solid hydrocarbon (D) include polymers of olefins having 2 to 20 carbon atoms. Among them, preferred are oligomers obtained by homopolymerizing an olefin having 2 to 20 carbon atoms, and oligomers obtained by copolymerizing two or more of these olefins.
Examples of the olefin having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, isobutene, 1-octene, 1-decene, and 1-dodecene.

As the hydrocarbon synthetic oil (C), an ethylene-based copolymer containing structural units derived from ethylene and structural units derived from an α-olefin having 3 to 20 carbon atoms can be suitably used. In this case, the content of the structural units derived from ethylene is preferably 30 mol% or more, more preferably 40 mol% or more, and is preferably 70 mol% or less, more preferably 60 mol% or less, relative to 100 mol% of the total content of the structural units derived from ethylene and the structural units derived from an α-olefin having 3 to 20 carbon atoms.

As the semi-solid hydrocarbon (D), it is preferable to use semi-solid polyisobutene. As the semi-solid hydrocarbon (D), a commercially available product may be used. Examples of the commercially available product include Tetrax and Himol manufactured by JXTG Nippon Oil & Energy Corporation, and polyisobutylene manufactured by Tomoe Engineering Co., Ltd.

The hydrocarbon synthetic oil (C) has a kinetic viscosity at 40° C. of 30 mm ² /s or more, preferably 300 mm ² /s or more, more preferably 5,000 mm ² /s or more, and 500,000 mm ² /s or less, preferably 400,000 mm ² /s or less, and even more preferably 300,000 mm ² /s or less. The hydrocarbon synthetic oil (C) has a kinetic viscosity at 200° C. of 10 mm ² /s or more, preferably 50 mm ² /s or more, more preferably 100 mm ² /s or more, and less than 1,000 mm ² /s, preferably 800 mm ² /s or less, and even more preferably 500 mm ² /s or less.
When the kinetic viscosity of the synthetic hydrocarbon oil (C) at 40° C. or 200° C., particularly at 40° C., is within the above range, an adhesive layer with high adhesive strength can be obtained.

The semi-solid hydrocarbon (D) has a kinetic viscosity at 200°C of 1,000 ^mm2 /s or more, preferably 1,100 ^mm2 /s or more, more preferably 1,200 ^mm2 /s or more, and 100,000 ^mm2 /s or less, preferably 80,000 ^mm2 /s or less, and even more preferably 60,000 ^mm2 /s or less.
When the kinetic viscosity at 200° C. of the semi-solid hydrocarbon (D) is within the above range, an adhesive layer having high adhesive strength can be obtained.

When the composition contains a hydrocarbon synthetic oil (C) and a semi-solid hydrocarbon (D), the total amount of the hydrocarbon synthetic oil (C) and the semi-solid hydrocarbon (D) is preferably 1 mass % or more and preferably 50 mass % or less, relative to 100 mass % of the total of the polymer (A), the hydrocarbon synthetic oil (C) and the semi-solid hydrocarbon (D).
When the blending amounts of the hydrocarbon synthetic oil (C) and the semi-solid hydrocarbon (D) are within the above ranges, an adhesive layer excellent in strength and adhesive strength can be obtained.

Method for preparing the composition
The composition can be prepared by mixing the polymer (A), the curing agent (B), and, if necessary, at least one selected from the group consisting of a hydrocarbon-based synthetic oil (C) and a semi-solid hydrocarbon (D).

Additionally, the composition may contain additives other than the above (A) to (D), such as polymer (a) (unmodified), monomer (b) (unmodified), curing catalyst, leveling agent, defoamer, antioxidant, heat stabilizer, light stabilizer such as ultraviolet absorber, plasticizer, surfactant, pigment such as titanium oxide (rutile type), zinc oxide, carbon black, thixotropic agent, thickener, tackifier such as rosin resin, terpene resin, surface conditioner, antisettling agent, weathering agent, pigment dispersant, antistatic agent, filler, organic or inorganic fine particles, antifungal agent, silane coupling agent, etc., within the scope of the present invention.

Furthermore, from the viewpoint of improving processability, the present composition may be a varnish containing a solvent in addition to the above components.
The solvent may be the same as that used in the synthesis of the polymer (A), and preferably includes toluene, a mixed solvent of methylcyclohexane/methyl isobutyl ketone, a mixed solvent of methylcyclohexane/methyl ethyl ketone, a mixed solvent of methylcyclohexane/ethyl acetate, a mixed solvent of cyclohexane/methyl ethyl ketone, a mixed solvent of cyclohexane/ethyl acetate, and a mixed solvent of cellosolve/cyclohexanone. Water may also be used as the dispersion medium.

It is desirable to mix the solvent so that the non-volatile content in 100% by mass of the varnish is, for example, 5% by mass or more, preferably 10% by mass or more, and, for example, 50% by mass or less, preferably 40% by mass or less.

This composition is suitable for use as a dry lamination adhesive, a hot melt adhesive, and a composition for optically transparent double-sided tape.

<Laminate>
The laminate according to the present invention (hereinafter also referred to as "the present laminate") is not particularly limited as long as it contains a substrate and an adhesive layer made of a cured product of the present composition, and may contain layers other than these.
In the present laminate, the adhesive layer may be present on one side or both sides of the substrate, or may be present on the entire surfaces or on only a part of these surfaces.

The method for producing the present laminate is not particularly limited and any conventionally known method can be used, but a method including a coating film formation step of forming a coating film from the present composition on a substrate and a curing step of curing the coating film is preferred.
In the method for producing the present laminate, all steps are preferably carried out at low temperatures (about 120°C or less, preferably 100°C or less) because this allows the laminate to be obtained without impairing the properties of the substrate or adherend (e.g., PP layer) and increases the freedom of choice for the substrate or adherend. Furthermore, by using the present composition, a laminate having excellent adhesive strength and chemical resistance (electrolyte resistance) can be obtained even when produced at such a low temperature.

As the coating film forming step, a method of forming a coating film by applying the composition onto a substrate and drying the composition as necessary, and a method of forming a coating film on a substrate by immersing the substrate in the composition, removing the substrate, and drying the composition as necessary are preferred.

The coating method is not particularly limited, and any conventionally known method can be used, such as die coating, flow coating, spray coating, bar coating, gravure coating, gravure reverse coating, kiss reverse coating, microgravure coating, roll coating, blade coating, rod coating, roll doctor coating, air knife coating, comma roll coating, reverse roll coating, transfer roll coating, kiss roll coating, curtain coating, and printing.

The substrate is not particularly limited, and may be any substrate on which the adhesive layer is to be formed, and may include, for example, a resin substrate made of a resin such as a polyolefin such as polyethylene or polypropylene, an ABS resin, a polyester resin such as polycarbonate (PC) or PET, a polyamide resin such as polyphenylene sulfide (PPS) or nylon, or an acrylic resin; a barrier film such as transparent deposition PET; an inorganic substrate made of an inorganic material such as ED steel plate, Mg alloy, SUS (stainless steel), aluminum, an aluminum alloy, or glass; a substrate made of a composite of the resin and an inorganic material; and a decorative film. Among these, metal foil, a polyolefin substrate, and a decorative film are preferred, and aluminum foil and a polyolefin substrate are more preferred.
The surface of the substrate that comes into contact with the adhesive layer may be subjected to a conventionally known surface treatment such as a corona treatment in order to improve adhesive strength.

The decorative film may be a film having a known design, and specific examples thereof include a film in which the resin base material or metal foil has been previously decorated by printing, painting, vapor deposition, etc., and a laminate of a film having a design and the resin base material or metal foil.
Examples of films having design properties include thermoplastic films such as acrylic films, PET films, PC films, COC (cyclic olefin copolymer) films, polyvinyl chloride films, and ABS films that have been given design properties.
The adhesive layer or the coating film may be provided with a design by a conventionally known method.

Methods for imparting design (decoration) include, for example, existing vacuum forming methods such as vacuum forming and compressed air vacuum forming, insert molding, in-mold molding, and the TOM method using the "vacuum forming device" described in Patent Publication No. 3733564. These methods can impart design to laminates with complex three-dimensional structures.

The thickness of the substrate is preferably 1 μm or more, more preferably 5 μm or more, and is preferably 500 μm or less, more preferably 100 μm or less.

Methods for drying the composition provided on the substrate include leaving the substrate with the composition at room temperature (about 20° C.) and normal pressure, drying the composition under reduced pressure, and heating the composition. The heating may be performed in one step or in two or more steps.
The heating conditions are not particularly limited as long as the conditions are such that volatile components such as the solvent are evaporated, and examples of the heating conditions include heating at 120° C. or lower, preferably 100° C. or lower, and at 40° C. or higher, for example, for 3 seconds or more, preferably 1 minute or more, and for example, for 1 hour or less.

The present laminate is usually used by adhering the adhesive layer to a desired adherend. That is, the present laminate may be an adhesive body in which a substrate, an adhesive layer, and an adherend are laminated in this order.
The adherend is preferably a polypropylene film in terms of exerting the effects of the present invention. The polypropylene film may be a stretched polypropylene film, but is preferably an unstretched polypropylene film. In the present invention, the terms film and sheet are synonymous.

The method for producing the adhesive body may involve applying the composition between the substrate and the adherend, optionally followed by the drying step, followed by a curing step, but it is preferable to bring the composition or coating into contact with the adherend before the drying step or after the coating film forming step, and then to carry out the curing step, and in particular the so-called dry lamination method is preferred.

The curing step may be a method of heating the coating film, which may be performed in one stage or in two or more stages.
The heating conditions are appropriately selected, and examples thereof include a method of curing at a low temperature, for example, 80° C. or less, preferably 70° C. or less, particularly preferably 60° C. or less, and for example, 40° C. or more, for example, 1 day or more, preferably 3 days or more, and for example, 7 days or less (low temperature curing method), and a method of curing at a high temperature, for example, 100° C. or more, preferably 120° C. or more, and for example, 200° C. or less, for example, 0.1 seconds or more, preferably 0.5 seconds or more, and for example, 60 seconds or less (high temperature curing method). Among these, the low temperature curing method is preferred from the viewpoints that a laminate can be obtained without impairing the properties of the substrate or adherend, and that the freedom of selection of the substrate or adherend is increased.

When bonding the substrate and the adherend, the substrate and the adherend may be bonded while applying pressure between them.
The pressure is, for example, 0.1 MPa or more, preferably 0.2 MPa or more, and preferably 2 MPa or less.

The thickness of the adhesive layer may be appropriately selected depending on the desired application, etc., and is not particularly limited, but is, for example, 0.2 μm or more, preferably 1 μm or more, and is, for example, 100 μm or less, preferably 20 μm or less.

The laminate can be used for, for example, automobile interior and exterior components; various front panels for AV equipment and the like; surface decorative materials such as buttons and emblems; housings for information appliances such as mobile phones and cameras; various parts such as housings, display windows and buttons; exterior materials for furniture; architectural interior materials such as bathroom surfaces, wall surfaces, ceilings and floors; architectural exterior materials such as exterior walls such as siding, fences, roofs, gates and gable boards; interior materials such as window frames, doors, handrails, thresholds, lintels and surface decorative materials for furniture; optical components such as various displays, lenses, mirrors, goggles and window glass; interior and exterior components for various vehicles other than automobiles such as trains, airplanes and ships; various containers such as bottles, cosmetic containers and accessory cases; packaging materials; and various other items.

Packaging materials
The packaging material according to the present invention includes a laminate in which a PP layer (inner layer), an adhesive layer, and a substrate are laminated in this order. The adhesive layer is a layer made of a cured product of the present composition.
Since the packaging material has the adhesive layer, it has excellent adhesive strength between the substrate and the PP layer, and also has excellent resistance to chemicals and electrolytes. Therefore, even if the packaging material is used for a long period of time, it is possible to effectively prevent a decrease in adhesive strength between the substrate and the PP layer, and it is possible to obtain a packaging material with excellent long-term reliability.

The packaging material is not particularly limited as long as it has a PP layer, an adhesive layer, and a substrate laminated in this order, and a conventionally known layer may be used between these layers or on the surface of the laminate.
Such packaging materials are suitable for use as packaging materials for batteries, which have excellent adhesive strength and chemical resistance (electrolyte resistance), as packaging materials for highly alkaline solutions, which have excellent adhesive strength and alkali resistance, and as packaging materials for alcohol-containing solutions, which have excellent adhesive strength and alcohol resistance.

In addition, as the packaging material, it is preferable to use one or two laminates in which a base material, an adhesive layer, and a PP layer are laminated in this order, or a laminate in which a PP layer, an inner adhesive layer, a base material, an outer adhesive layer, and an outer layer are laminated in this order, by thermocompression bonding so that the PP layers are in contact, and then use the resulting packaging material (thermocompression-bonded body).
In particular, according to the present invention, since the adhesive layer is included, even if such thermocompression bonding is performed, the thickness of the parts that were the two PP layers in the thermocompression bonded body does not decrease significantly from the total thickness of the two PP layers before thermocompression bonding.

The conditions for the thermocompression bonding may be appropriately set according to the type of each layer used, but when a thermoplastic polyolefin film such as an unstretched polypropylene film or a low-density linear polyethylene film is used as the PP layer, the heating temperature is preferably 160°C or higher, more preferably 170°C or higher, and preferably 200°C or lower, more preferably 190°C or lower, the thermocompression bonding time depends on the heating temperature, but is preferably 0.5 seconds or higher, and preferably 5 seconds or lower, and the pressure applied during thermocompression bonding is preferably 2.0 MPa or higher, and preferably 4.0 MPa or lower.

The PP layer corresponds to the adherend described in the laminate section, and may be a layer similar to the adherend, but when the packaging material is used as a packaging material for highly alkaline solutions or alcohol-containing solutions, an unstretched polypropylene film is preferred in order to impart chemical resistance (electrolyte resistance), heat sealability, etc. to the packaging material.

The substrate may be the same as the substrate described in the laminate section, but is not particularly limited.

The thickness of the packaging material may be appropriately selected depending on the desired application, but is, for example, 30 μm or more and, for example, 200 μm or less.

The packaging material may be used in the form of a bag with the PP layer on the inside so that the contents, such as a highly alkaline solution or an alcohol-containing solution, come into contact with the PP layer.

The highly alkaline solution may be a solution having a pH of, for example, 9 or more, preferably 10 or more. Specific examples include alkaline detergents and hair treatment agents.
Examples of the alcohol-containing solution include solutions containing methanol, ethanol, propanol, ethylene glycol, etc. The alcohol concentration in the alcohol-containing solution is, for example, 3% by mass or more, preferably 5% by mass or more, and is, for example, 95% by mass or less, preferably 80% by mass or less.

<Battery packaging>
The battery packing material according to the present invention includes a laminate in which a PP layer, an inner adhesive layer, a substrate, an outer adhesive layer, and an outer layer are laminated in this order, the inner adhesive layer being a layer made of a cured product of the present composition.
Since the battery packing material has the adhesive layer, it has excellent adhesive strength between the substrate and the PP layer and excellent resistance to electrolyte, and therefore even if the battery packing material is used for a long period of time, it is possible to effectively prevent a decrease in adhesive strength between the substrate and the PP layer, and it is possible to obtain a battery packing material with excellent long-term reliability.

The battery packaging material is not particularly limited as long as it is made up of a PP layer, an inner adhesive layer, a base material, an outer adhesive layer, and an outer layer laminated in this order, and a conventionally known layer may be used between these layers or on the surface of the laminate.

The PP layer may be the same as the PP layer described in the packaging material section.

The substrate may be the same as the substrate described in the laminate section, and is not particularly limited, but is preferably a metal foil, and more preferably an aluminum foil or a stainless steel foil. In addition, the substrate surface may be subjected to a chemical conversion treatment from the viewpoint of corrosion resistance, etc.

The outer adhesive layer may be any layer that bonds the outer layer to the substrate, and may be a layer made of a cured product of the present composition, or may be a layer obtained using a conventionally known adhesive such as a dry lamination adhesive or a solventless adhesive.

The outer layer is not particularly limited, but is preferably a multilayer film formed by laminating a single layer or two or more layers of stretched or unstretched films such as polyester film, polyamide film, and polypropylene film in order to provide heat resistance in the heat sealing process during battery production, formability during processing, pinhole resistance, insulation during distribution, etc.

The thickness of the battery packaging material is, for example, 60 μm or more and, for example, 160 μm or less.

<Batteries>
The battery according to the present invention is a battery comprising the battery packing material and an electrolyte solution packed in the battery packing material, and at least a part of the PP layer of the battery packing material is in contact with the electrolyte solution. The battery is not particularly limited, but may be, for example, a lithium ion secondary battery.
The battery will now be described with reference to FIG. 1, which shows one embodiment of the battery.

1, the battery 10 includes a battery packing material 1 and an electrolyte solution 11 packaged in the battery packing material 1. The battery 10 also includes a positive electrode 17, a negative electrode 18, and a separator 19 housed in the battery packing material 1.
In this battery, the battery packaging material 1 is configured in a bag shape so that the electrolyte 11 comes into contact with the inner surface of the PP layer 3 in the battery packaging material 1, and the battery packaging material 1 is a laminate in which, from the inside, a PP layer 3, an inner adhesive layer 5, a substrate 2, an outer adhesive layer 6 and an outer layer 4 are laminated in this order.

The electrolyte solution 11 is not particularly limited, and examples thereof include electrolyte solutions containing ethylene carbonate, diethyl carbonate, dimethyl carbonate, and lithium salts such as lithium hexafluorophosphate.

The positive electrode 17 and the negative electrode 18 are arranged opposite each other with a space between them, so as to be in contact with the electrolyte 11, and with a separator 19 interposed therebetween.

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

<Content of structural units derived from propylene, ethylene and 1-butene>
The contents of structural units derived from propylene, ethylene and 1-butene in the polymers obtained in the following Production Examples (hereinafter also referred to as "propylene content", "ethylene content" and "1-butene content") were measured by ¹³ C-NMR.

<Melting point and heat of fusion>
The melting points (Tm) and heat of fusion (ΔH) of the polymers obtained in the following Production Examples were determined using a differential scanning calorimeter (DSC-Q1000 manufactured by TA Instruments). The specific method is as described above.

<Weight average molecular weight (Mw)>
A chromatogram was obtained under the following conditions using a gel permeation chromatograph (LC-10 series, manufactured by Shimadzu Corporation). From the obtained chromatogram, the Mw of the polymer obtained in the following Production Example was calculated using a calibration curve prepared using monodisperse standard polystyrene.

Detector: Shimadzu Corporation; C-R4A
Column: TSKG 6000H-TSKG 4000H-TSKG 3000H-TSKG 2000H (all manufactured by Tosoh Corporation)
Mobile phase: Tetrahydrofuran Temperature: 40°C
Flow rate: 0.8 mL / min

<Amount of modification>
The content (modification amount) of structural units derived from maleic anhydride in the polymers obtained in the following Production Examples was determined by ¹ H-NMR measurement, the specific method being as described above.

<Kinematic Viscosity at 40° C. or 200° C.>
The kinetic viscosity at 40° C. or 200° C. of the polymers obtained in the following Production Examples was measured in accordance with ASTM D 445.

[Production Example 1-1] Synthesis of propylene/1-butene copolymer (a1) 900 mL of hexane and 80 g of 1-butene were charged into a 2 L autoclave that had been thoroughly purged with nitrogen, 1 mmol of triisobutylaluminum was added, and the temperature was raised to 70° C., after which propylene was fed to a total pressure of 7 kg/cm ² G. Next, 0.30 mmol of methylaluminoxane and 0.001 mmol of rac-dimethylsilylene-bis{1-(2-methyl-4-phenylindenyl)}zirconium dichloride calculated as Zr atoms were added, and polymerization was carried out for 30 minutes while continuously feeding propylene to maintain the total pressure at 7 kg/cm ² G. After polymerization, the polymer was degassed and collected in a large amount of methanol, and dried under reduced pressure at 110° C. for 12 hours to obtain a propylene/1-butene copolymer (a1).
The resulting propylene/1-butene copolymer (a1) had a melting point of 89.2° C., a heat of fusion of 31.5 J/g, Mw of 330,000 and a propylene content of 73.5 mol %.

[Production Example 1-2] Synthesis of modified olefin polymer (A-1) 3 kg of the propylene/1-butene copolymer (a1) was added to 10 L of toluene, and the temperature was raised to 145° C. under a nitrogen atmosphere to dissolve the copolymer (a1) in toluene. Furthermore, 153 g of maleic anhydride and 175 g of di-tert-butyl peroxide were fed to the system over 4 hours under stirring, and the mixture was then stirred at 145° C. for 2 hours. After cooling, a large amount of acetone was added to precipitate the modified copolymer, which was then filtered, washed with acetone, and dried in vacuum.
The resulting maleic anhydride-modified propylene/1-butene copolymer (modified olefin polymer (A-1)) had a melting point of 85.9°C, a heat of fusion of 29.9 J/g, and Mw of 110,000. The modification amount of maleic anhydride was 0.4% by mass relative to 100% by mass of the modified olefin polymer (A-1).

[Production Example 1-3] Synthesis of modified olefin polymer (A-2) 3 kg of the propylene/1-butene copolymer (a1) was added to 10 L of toluene, and the temperature was raised to 145° C. under a nitrogen atmosphere to dissolve the copolymer (a1) in toluene. Furthermore, 229 g of maleic anhydride and 175 g of di-tert-butyl peroxide were fed to the system over 4 hours under stirring, and the mixture was then stirred at 145° C. for 2 hours. After cooling, a large amount of acetone was added to precipitate the modified copolymer, which was then filtered, washed with acetone, and dried in vacuum.
The resulting maleic anhydride-modified propylene/1-butene copolymer (modified olefin polymer (A-2)) had a melting point of 86.2°C, a heat of fusion of 30.4 J/g, and Mw of 103,000. The modification amount of maleic anhydride was 0.6% by mass relative to 100% by mass of the modified olefin polymer (A-2).

[Production Example 1-4] Synthesis of modified olefin polymer (A-3) 3 kg of the propylene/1-butene copolymer (a1) was added to 10 L of toluene, and the temperature was raised to 145° C. under a nitrogen atmosphere to dissolve the copolymer (a1) in toluene. Furthermore, 306 g of maleic anhydride and 175 g of di-tert-butyl peroxide were fed to the system over 4 hours under stirring, and the mixture was then stirred at 145° C. for 2 hours. After cooling, a large amount of acetone was added to precipitate the modified copolymer, which was then filtered, washed with acetone, and vacuum dried.
The resulting maleic anhydride-modified propylene/1-butene copolymer (modified olefin polymer (A-3)) had a melting point of 85.2°C, a heat of fusion of 27.9 J/g, and Mw of 110,000. The modification amount of maleic anhydride was 0.8% by mass relative to 100% by mass of the modified olefin polymer (A-3).

[Production Example 1-5] Synthesis of Modified Olefin Polymer (A-4) 3 kg of the propylene/1-butene copolymer (a1) was added to 10 L of toluene, and the temperature was raised to 145° C. under a nitrogen atmosphere to dissolve the copolymer (a1) in toluene. Furthermore, 382 g of maleic anhydride and 175 g of di-tert-butyl peroxide were fed to the system under stirring over 4 hours, and the mixture was then stirred at 145° C. for 2 hours. After cooling, a large amount of acetone was added to precipitate the modified copolymer, which was then filtered, washed with acetone, and dried in vacuum.
The resulting maleic anhydride-modified propylene/1-butene copolymer (modified olefin polymer (A-4)) had a melting point of 84.5°C, a heat of fusion of 29.3 J/g, and Mw of 108,000. The modification amount of maleic anhydride was 0.9% by mass relative to 100% by mass of the modified olefin polymer (A-4).

[Production Example 1-6] Synthesis of modified olefin polymer (A-5) 3 kg of the propylene/1-butene copolymer (a1) was added to 10 L of toluene, and the temperature was raised to 145° C. under a nitrogen atmosphere to dissolve the copolymer in toluene. Furthermore, 1.3 kg of maleic anhydride and 175 g of di-tert-butyl peroxide were fed to the system under stirring over 4 hours, and the mixture was then stirred at 145° C. for 2 hours. After cooling, a large amount of acetone was added to precipitate the modified copolymer, which was then filtered, washed with acetone, and vacuum dried.
The resulting maleic anhydride-modified propylene/1-butene copolymer (modified olefin polymer (A-5)) had a melting point of 74.3°C, a heat of fusion of 28.0 J/g, and Mw of 105,000. The modification amount of maleic anhydride was 3.5% by mass relative to 100% by mass of the modified olefin polymer (A-5).

[Production Example 1-7] Synthesis of 1-butene/ethylene copolymer (a2) 900 mL of hexane and 80 g of ethylene were charged into a 2 L autoclave that had been thoroughly purged with nitrogen, 1 mmol of triisobutylaluminum was added, and the temperature was raised to 70° C., after which 1-butene was fed to a total pressure of 7 kg/cm ² G. Next, 0.30 mmol of methylaluminoxane and 0.001 mmol of rac-dimethylsilylene-bis{1-(2-methyl-4-phenylindenyl)}zirconium dichloride calculated as Zr atoms were added, and polymerization was carried out for 30 minutes while continuously feeding 1-butene to maintain the total pressure at 7 kg/cm ² G. After polymerization, the polymer was degassed and collected in a large amount of methanol, and dried under reduced pressure at 110° C. for 12 hours to obtain 1-butene/ethylene copolymer (a2).
The resulting 1-butene/ethylene copolymer (a2) had a melting point of 80° C., a heat of fusion of 34.4 J/g, Mw of 180,000 and a 1-butene content of 98.5 mol %.

[Production Example 1-8] Synthesis of modified olefin polymer (A-6) 3 kg of the 1-butene/ethylene copolymer (a2) was added to 10 L of toluene, and the temperature was raised to 145°C under a nitrogen atmosphere to dissolve the copolymer (a2) in toluene. Furthermore, 153 g of maleic anhydride and 175 g of di-tert-butyl peroxide were fed to the system over 4 hours under stirring, and the mixture was then stirred at 145°C for 2 hours. After cooling, a large amount of acetone was added to precipitate the modified copolymer, which was then filtered, washed with acetone, and dried in vacuum.
The resulting maleic anhydride-modified 1-butene/ethylene copolymer (modified olefin polymer (A-6)) had a melting point of 79.3°C, a heat of fusion of 13.2 J/g, and Mw of 110,000. The modification amount of maleic anhydride was 0.4% by mass relative to 100% by mass of the modified olefin polymer (A-6).

[Production Example 1-9] Synthesis of Modified Olefin Polymer (A-7) 3 kg of the 1-butene/ethylene copolymer (a2) was added to 10 L of toluene, and the temperature was raised to 145° C. under a nitrogen atmosphere to dissolve the copolymer (a2) in toluene. Furthermore, 382 g of maleic anhydride and 175 g of di-tert-butyl peroxide were fed to the system under stirring over 4 hours, and the mixture was then stirred at 145° C. for 2 hours. After cooling, a large amount of acetone was added to precipitate the modified copolymer, which was then filtered, washed with acetone, and vacuum dried.
The resulting maleic anhydride modified 1-butene/ethylene copolymer (modified olefin polymer (A-7)) had a melting point of 78.2°C, a heat of fusion of 16.5 J/g, and Mw of 160,000. The modification amount of maleic anhydride was 0.9% by mass relative to 100% by mass of the modified olefin polymer (A-7).

Production Example 2-1 Synthesis of Hydrocarbon Synthetic Oil (C-1) 1 L of dehydrated and purified hexane was added to a continuous polymerization reactor equipped with an agitator and thoroughly purged with nitrogen, and a hexane solution of ethylaluminum sesquichloride (Al( _C2H5 ) _{1.5.Cl1.5 )} adjusted to 96 _mmol /L was continuously fed at a rate of 500 mL/h for 1 hour, after which a hexane solution of VO( _OC2H5 ) _Cl2 adjusted to 16 mmol/ _L as a catalyst was continuously fed at 500 mL/h, and hexane was continuously fed at 500 mL/h. Meanwhile, the polymerization liquid was continuously withdrawn from the top of the reactor so that the polymerization liquid in the reactor was always 1 L.
Next, ethylene gas was supplied at a rate of 47 L/h, propylene gas at a rate of 47 L/h, and hydrogen gas at a rate of 20 L/h using a bubbling tube. The copolymerization reaction was carried out at 35° C. by circulating a coolant through a jacket attached to the outside of the reactor. The obtained polymerization solution was deashed with hydrochloric acid, then poured into a large amount of methanol for precipitation, and then dried under reduced pressure at 130° C. for 24 hours.
The resulting ethylene/propylene copolymer (hydrocarbon synthetic oil (C-1)) had an ethylene content of 55.9 mol %, Mw of 14,000, a kinetic viscosity at 40°C of 37,500 mm ² /s and a kinetic viscosity at 200°C of 132 mm ² /s.

[Example 1]
The main component of the adhesive composition was prepared by dissolving 100 g of the modified olefin polymer (A-3) in 400 g of a mixed solvent of methylcyclohexane/ethyl acetate = 80/20 (mass ratio) under heating and cooling.
The prepared base component was mixed with 3 g of Takenate D-170N (a polyisocyanate curing agent manufactured by Mitsui Chemicals, Inc.) as a curing agent component to prepare an adhesive composition.

[Example 2]
An adhesive composition was prepared in the same manner as in Example 1, except that 80 g of the modified olefin polymer (A-3) and 20 g of the hydrocarbon synthetic oil (C-1) were used instead of 100 g of the modified olefin polymer (A-3).

[Example 3]
An adhesive composition was prepared in the same manner as in Example 2, except that the modified olefin polymer (A-4) was used instead of the modified olefin polymer (A-3).

[Example 4]
An adhesive composition was prepared in the same manner as in Example 2, except that the modified olefin polymer (A-7) was used instead of the modified olefin polymer (A-3).

[Example 5]
An adhesive composition was prepared in the same manner as in Example 4, except that 5 g of Celloxide 2021P (manufactured by Daicel Corporation, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate) was used instead of 3 g of Takenate D-170N.

[Comparative Example 1]
An adhesive composition was prepared in the same manner as in Example 2, except that the modified olefin polymer (A-1) was used instead of the modified olefin polymer (A-3).

[Comparative Example 2]
An adhesive composition was prepared in the same manner as in Example 2, except that the modified olefin polymer (A-2) was used instead of the modified olefin polymer (A-3).

[Comparative Example 3]
An adhesive composition was prepared in the same manner as in Example 1, except that the modified olefin polymer (A-5) was used instead of the modified olefin polymer (A-3).

[Comparative Example 4]
An adhesive composition was prepared in the same manner as in Example 2, except that the modified olefin polymer (A-6) was used instead of the modified olefin polymer (A-3).

<Acid value>
35 mL of toluene and 15 mL of n-butanol were placed in an Erlenmeyer flask, and 0.8 g of a diluted solution prepared by diluting 0.1 g of special grade bromothymol blue (Kanto Chemical Co., Ltd.) with 100 mL of 19% ethanol was added thereto. 0.1 mol/L KOH ethanol solution was added to the resulting solution until the solution turned green, and 5 g of each of the main components obtained in the examples and comparative examples was added thereto and completely dissolved. The resulting solution was titrated with 0.1 mol/L KOH ethanol solution until the solution turned blue.
The acid value was calculated from the titration amount using the following formula. The results are shown in Table 1.
Acid value (KOH mg/g) = (B x f x 5.611) / S
[B is the amount (mL) of 0.1 mol/L KOH ethanol solution used in the titration,
f is the factor of a 0.1 mol/L KOH ethanol solution,
S is the mass (g) of the base agent used.

<Al/CPP adhesive strength>
The adhesive compositions obtained in the Examples and Comparative Examples were applied to an Al foil having a thickness of 30 μm, and dried at 100° C. for 1 minute (dry film thickness: about 3 μm). Then, the adhesive-coated surface of the Al foil was bonded to the corona-treated surface of a 30 μm-thick unstretched polypropylene film (CPP film, one-sided corona treatment), and cured at 60° C. for 3 days to obtain a laminate (Al/CPP). The obtained laminate was cut into a width of 15 mm to prepare a test piece, and a 180° peel test was performed on this test piece using a universal tensile measuring device (manufactured by Intesco Co., Ltd.) at a crosshead speed of 50 mm/min to measure the peel strength (Al/CPP adhesive strength) between the Al foil and the CPP film. The results are shown in Table 1.

<CPP retention rate>
A laminate (Al/CPP) was obtained in the same manner as in the measurement of the Al/CPP adhesive strength. Two of the obtained laminates were overlapped so that the CPP films of these laminates were in contact with each other, and in this state, they were thermocompression-bonded using a heat sealer (TP-701-B, manufactured by Tester Sangyo Co., Ltd.) under conditions of a heating temperature (upper and lower surface temperature of the heat sealer) of 185° C., a pressure of 3.7 MPa, and a sealing time of 3 seconds, to obtain a laminate (Al/CPP/CPP/Al).
The ratio of the total film thickness after thermocompression bonding to the total film thickness of Al/CPP/CPP/Al before thermocompression bonding (CPP retention rate) was calculated based on the following formula (1) and evaluated according to the following criteria.
CPP retention rate={30×2−(total film thickness before bonding−total film thickness after bonding)}×100/(30×2) (1)
◎: CPP retention rate is 40% or more. ○: CPP retention rate is 30% or more and less than 40%. △: CPP retention rate is 20% or more and less than 30%. ×: CPP retention rate is less than 20%.

Because the thickness of the Al foil does not change before and after the thermocompression bonding, and the ratio of the thickness of the adhesive layer to the total thickness of the laminate is small, it is believed that the change in the total thickness of the laminate is mainly due to the change in the thickness of the CPP film. Therefore, the retention calculated by the above formula (1) can be said to correspond to the retention of the thickness of the CPP film (CPP retention).

<Pot life>
The viscosity at 25° C. of the adhesive composition immediately after preparation in each of the examples and comparative examples (viscosity immediately after preparation) was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.).
Next, 40 mL of the adhesive composition immediately after preparation in each of the Examples and Comparative Examples was placed in a container, and the container was immersed in a water bath at 25° C. for one day, and the viscosity of the adhesive composition after one day (viscosity after one day) was measured using a similar B-type viscometer.
The ratio of the viscosity after one day to the viscosity immediately after preparation (viscosity after one day/viscosity immediately after preparation) was calculated, and the pot life was evaluated according to the following criteria.
⊚: The ratio is 1 or more and less than 2. ◯: The ratio is 2 or more and less than 3. △: The ratio is 3 or more. ×: The viscosity after 1 day cannot be measured.

1: Battery packaging material 2: Base material 3: PP layer 4: Outer layer 5: Inner adhesive layer 6: Outer adhesive layer 10: Battery 11: Electrolyte 17: Positive electrode 18: Negative electrode 19: Separator

Claims (10)

A modified olefin polymer (A) is an α-olefin polymer having 2 to 20 carbon atoms modified with a polar group-containing monomer (b), and satisfies the following requirements (i) to (iii):
A curing agent (B);
1. An adhesive composition comprising:
Requirement (i): The polymer (a) contains a structural unit derived from ethylene and a structural unit derived from an α-olefin having 4 to 20 carbon atoms , and the content of the structural unit derived from the α-olefin having 4 to 20 carbon atoms is 70 to 99.8 mol % relative to 100 mol % of the structural units derived from the α-olefin having 2 to 20 carbon atoms.
Requirement (ii): The heat of fusion of the olefin polymer (A), as measured in accordance with JIS K 7122, is 0 J/g or more and 50 J/g or less. Requirement (iii): The content of the structural unit derived from the monomer (b) in 100 mass% of the olefin polymer (A) is 0.7 to 3.0 mass%. 2. The adhesive composition according to claim 1, comprising at least one selected from the group consisting of a synthetic hydrocarbon oil (C) having a kinetic viscosity at 40°C of 30 to 500,000 mm ² /s and a semi-solid hydrocarbon (D) having a kinetic viscosity at 200°C of 1,000 to 100,000 mm ² /s. The adhesive composition according to claim 1 or 2, wherein the α-olefin having 4 to 20 carbon atoms comprises 1-butene. The adhesive composition according to any one of claims 1 to 3, wherein the polar group is a carboxyl group or an acid anhydride group. The adhesive composition according to any one of claims 1 to 4, wherein the curing agent (B) is a polyisocyanate. An adhesive composition comprising a base component and a curing agent component,
The main component contains the polymer (A),
The acid value of the base component is 0.9 to 5.0 mgKOH/g when the non-volatile content of the base component is 20% by mass.
The adhesive composition according to any one of claims 1 to 5. A laminate comprising a substrate and an adhesive layer made of a cured product of the adhesive composition according to any one of claims 1 to 6. The laminate includes a polypropylene layer, an adhesive layer, and a substrate in this order,
A packaging material, wherein the adhesive layer is a layer made of a cured product of the adhesive composition according to any one of claims 1 to 6. The laminate includes a polypropylene layer, an inner adhesive layer, a substrate, an outer adhesive layer, and an outer layer in this order,
A battery packing material, wherein the inner adhesive layer is a layer made of a cured product of the adhesive composition according to any one of claims 1 to 6. A battery comprising the packing material for a battery according to claim 9 and an electrolyte solution packaged in the packing material for a battery, wherein at least a portion of the polypropylene layer of the packing material for a battery is in contact with the electrolyte solution.

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