JP2016066515A - Nonwoven fabric for power storage device separator, power storage device, and resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonwoven fabric for a power storage device separator, which is superior in tensile strength, piercing strength, and the flexibility in winding a separator and achieves good balance among them.SOLUTION: A nonwoven fabric for a power storage device separator according to the invention comprises: a conjugated diene based (co)polymer having a polymer block (A) including a constitutional unit (a-1) originating a first conjugated diene compound and having a vinyl bond content less than 30 mol%, and a polymer block (B) including a constitutional unit (b-1) originating a second conjugated diene compound and having a vinyl bond content or 30 mol% or more; and a thermoplastic resin.SELECTED DRAWING: None

Description

  The present invention relates to a nonwoven fabric suitably used for an electricity storage device separator, an electricity storage device including the nonwoven fabric, and a resin composition for producing the nonwoven fabric.

  An electricity storage device such as a primary battery, a secondary battery, a lithium ion capacitor, or an electric double layer capacitor includes a pair of electrodes and a separator and is impregnated with an electrolyte solution for driving an electricity storage device. Used in various electrical and electronic equipment.

  With the recent miniaturization and higher efficiency of electronic devices, power storage devices are required to have high functionality such as long life, high reliability, and high energy density. There is. The electricity storage device separator is a material for isolating the positive electrode and the negative electrode in the electricity storage device and holding the electrolytic solution to ensure ionic conductivity between the positive electrode and the negative electrode.

  The main separators currently used include synthetic resin porous membranes and non-woven fabrics. Synthetic resin porous membranes have the advantage of high reliability, but improvements are required in terms of capacity, current density, heat resistance, cost, and the like. On the other hand, a separator made of nonwoven fabric has an advantage that a porous film can be produced at a low process cost and can be formed from a material having high heat resistance.

  Non-woven fabric separators are required to have a certain level of tensile strength and pin puncture strength to withstand the manufacturing and assembly process of an electricity storage device, and in a wound secondary battery comprising an electrode group having an electrode, a separator, and an axis. In addition to the mechanical properties described above, flexibility is also required when winding the separator.

  In response to such demands, for example, for the purpose of improving tensile strength, a battery separator made of a nonwoven fabric containing a core-sheath composite fiber having polypropylene as a core component and polyethylene as a sheath component has been proposed. (See Patent Document 1). Moreover, the separator for electrochemical elements which consists of the wet nonwoven fabric containing a specific liquid crystalline polymer fiber and organic fiber is proposed as what aims at coexistence of tensile strength and puncture strength (refer patent document 2).

JP 2014-71994 A Japanese Patent No. 4244294

  However, in the separator disclosed in Patent Document 1, the flexibility at the time of winding is insufficient, and the problem of insufficient strength due to the sheath core structure has not been solved yet. In addition, the separator disclosed in Patent Document 2 is spun from a state in which a liquid crystalline polymer is melted or dissolved in a solvent and is made into a fiber, and thus has a problem that the manufacturing cost increases, and the flexibility is increased. There are still challenges.

  Accordingly, some aspects of the present invention provide an electricity storage device that is excellent in tensile strength, puncture strength, flexibility during winding of the separator, and has a good balance by solving at least a part of the above problems. A nonwoven fabric for a separator is provided.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the nonwoven fabric for electricity storage device separator according to the present invention is:
A polymer block (A) containing a structural unit (a-1) derived from the first conjugated diene compound and having a vinyl bond content of less than 30 mol%, and a structural unit derived from the second conjugated diene compound (b -1) and a conjugated diene (co) polymer having a polymer block (B) having a vinyl bond content of 30 mol% or more,
A thermoplastic resin;
It is the nonwoven fabric containing this.

[Application Example 2]
In the nonwoven fabric for electricity storage device separator of Application Example 1,
The first conjugated diene compound is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene. And at least one compound selected from the group consisting of 4,5-diethyl-1,3-octadiene and chloroprene.

[Application Example 3]
In the nonwoven fabric for electricity storage device separator of Application Example 1 or Application Example 2,
The second conjugated diene compound is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene. And at least one compound selected from the group consisting of 4,5-diethyl-1,3-octadiene and chloroprene.

[Application Example 4]
In the nonwoven fabric for electricity storage device separator of any one of Application Examples 1 to 3,
The content of the thermoplastic resin in the nonwoven fabric can be 70% by mass or more and 99% by mass or less when the total amount of the conjugated diene (co) polymer and the thermoplastic resin is 100% by mass. .

[Application Example 5]
In the nonwoven fabric for electricity storage device separator of any one of Application Examples 1 to 4,
The conjugated diene (co) polymer may be hydrogenated.

[Application Example 6]
In the nonwoven fabric for electricity storage device separator of any one of Application Examples 1 to 5,
The thermoplastic resin may be a polyolefin.

[Application Example 7]
In the nonwoven fabric for electricity storage device separator of Application Example 6,
The polyolefin may be at least one selected from the group consisting of polyethylene and polypropylene.

[Application Example 8]
One aspect of the electricity storage device according to the present invention is:
A non-woven fabric for an electricity storage device separator according to any one of Application Examples 1 to 7 is provided.

[Application Example 9]
One aspect of the resin composition according to the present invention is:
A resin composition for producing a nonwoven fabric for an electricity storage device separator,
A polymer block (A) containing a structural unit (a-1) derived from the first conjugated diene compound and having a vinyl bond content of less than 30 mol%, and a structural unit derived from the second conjugated diene compound (b -1) and a conjugated diene (co) polymer having a polymer block (B) having a vinyl bond content of 30 mol% or more,
A thermoplastic resin;
It is characterized by containing.

[Application Example 10]
In the resin composition of Application Example 9,
The first conjugated diene compound is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene. And at least one compound selected from the group consisting of 4,5-diethyl-1,3-octadiene and chloroprene.

[Application Example 11]
In the resin composition of Application Example 9 or Application Example 10,
The second conjugated diene compound is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene. And at least one compound selected from the group consisting of 4,5-diethyl-1,3-octadiene and chloroprene.

  According to the nonwoven fabric for an electricity storage device separator according to the present invention, the tensile strength, the puncture strength, and the flexibility during winding of the separator are excellent, and these balances are good.

  Hereinafter, preferred embodiments according to the present invention will be described in detail. It should be understood that the present invention is not limited only to the embodiments described below, and includes various modifications that are implemented within a scope that does not change the gist of the present invention.

1. Non-woven fabric for electricity storage device separator Non-woven fabric for electricity storage device separator (hereinafter, also simply referred to as “nonwoven fabric”) according to the present embodiment includes an conjugated diene-based (co) polymer and a thermoplastic resin. It is the nonwoven fabric used as. The conjugated diene-based (co) polymer includes a structural unit (a-1) derived from the first conjugated diene compound and a polymer block (A) having a vinyl bond content of less than 30 mol%, a second (Co) polymer having a structural unit (b-1) derived from a conjugated diene compound and having a polymer block (B) having a vinyl bond content of 30 mol% or more. The nonwoven fabric which concerns on this Embodiment can be manufactured from the composition containing the said conjugated diene type | system | group (co) polymer, a thermoplastic resin, and another component as needed. Hereinafter, each component which comprises the nonwoven fabric for electrical storage device separators which concerns on this Embodiment is demonstrated in detail.

1.1. Conjugated diene-based (co) polymer The conjugated diene-based (co) polymer is also referred to as a structural unit (a-1) derived from the first conjugated diene compound (hereinafter, also simply referred to as “structural unit (a-1)”). ) Containing a polymer block (A) and a second
And a polymer block (B) containing the structural unit (b-1) derived from the conjugated diene compound (hereinafter also simply referred to as “structural unit (b-1)”). A conjugated diene-based (co) polymer that is hydrogenated (hereinafter also referred to as “hydrogenation”) as necessary.

1.1.1. Polymer block (A)
Examples of the first conjugated diene compound include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3. -Hexadiene, 4,5-diethyl-1,3-octadiene, chloroprene and the like. Among these, 1,3-butadiene, isoprene, and 1,3-pentadiene are preferable, and 1,3-butadiene and isoprene are more preferable from the viewpoint of obtaining a nonwoven fabric that can be industrially used and has excellent characteristics. In addition, the 1st conjugated diene compound may be used individually by 1 type, and may use 2 or more types together.

  The structural unit (a-1) is preferably a structural unit containing 95 to 100% by mass of a structural unit derived from 1,3-butadiene, and is a structural unit composed only of a structural unit derived from 1,3-butadiene. More preferably.

  The structural unit (a-1) in the polymer block (A) is preferably contained in the polymer block (A) in an amount of 95% by mass or more from the viewpoint of maintaining fluidity at the time of forming the nonwoven fabric. More preferably, it is composed only of (a-1).

  The vinyl bond content in the polymer block (A) is required to be less than 30 mol%, preferably 20 mol% or less, from the viewpoint of improving mechanical strength such as tensile strength and puncture strength. More preferably, it is 18 mol% or less. The lower limit of the vinyl bond content in the polymer block (A) is not particularly limited.

  The “vinyl bond content” in the present invention means a conjugated diene compound incorporated in a polymer block before hydrogenation in a 1,2-bond, 3,4-bond, and 1,4-bond bond mode. Among these, the total ratio (based on mol%) of those incorporated by 1,2-bonds and 3,4-bonds.

1.1.2. Polymer block (B)
As the second conjugated diene compound, for example, the same compound as the first conjugated diene compound described above can be used, and preferred compounds are also the same. Note that the second conjugated diene compound and the first conjugated diene compound may be the same or different.

  The polymer block (B) is a polymer block containing the structural unit (b-1) derived from the second conjugated diene compound. From the viewpoint of imparting flexibility to the nonwoven fabric and preventing crystallization of the polymer block (B), the polymer block (B) is a structural unit derived from an alkenyl aromatic compound (hereinafter “structural unit (b-2)”. It may also be a polymer block further comprising “)”.

  The structural unit (b-1) is preferably a structural unit containing 95 to 100% by mass of a structural unit derived from 1,3-butadiene and / or isoprene, and derived from 1,3-butadiene and / or isoprene. More preferably, the structural unit is composed of only structural units.

  The structural unit (b-1) in the polymer block (B) is preferably contained in the polymer block (B) in an amount of 50% by mass or more, more preferably 70 to 100% by mass, and more preferably 80 to It is particularly preferable to contain 100% by mass.

  When the polymer block (B) further contains the structural unit (b-2), the structural unit (b-2) in the polymer block (B) is a polymer from the viewpoint of maintaining fluidity during the molding process of the nonwoven fabric. It is preferable that 50 mass% or less is contained in the block (B).

  The mass ratio of the structural unit (b-1) / structural unit (b-2) in the polymer block (B) is preferably 100/0 to 50/50, more preferably 100/0 to 70/30, and particularly preferably. Is 100/0 to 80/20.

  Examples of the alkenyl aromatic compound include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, N, N-diethyl-p-aminostyrene, and vinylpyridine. Among these, styrene and α-methylstyrene are preferable. When the polymer block (B) is a copolymer block containing the structural unit (b-1) and the structural unit (b-2), the distribution of the structural unit (b-1) is random, tapered ( Those in which the structural unit (b-1) increases or decreases along the molecular chain), a partial block shape, or any combination thereof.

  The vinyl bond content in the polymer block (B) needs to be 30 mol% or more, preferably 30 to 95 mol%, more preferably 30 to 85 mol%, Particularly preferred is 75 mol%. When the vinyl bond content in the polymer block (B) is 30 mol% or more, the resulting nonwoven fabric can be obtained without impairing the mechanical strength such as tensile strength and puncture strength imparted by the polymer block (A). Flexibility can be imparted.

1.1.3. Polymer block (C)
In addition to the polymer block (A) and the polymer block (B), the block copolymer further contains 50 structural units derived from an alkenyl aromatic compound (hereinafter also referred to as “structural unit (c-1)”). You may have a polymer block (C) containing exceeding mass%. The polymer block (C) is preferably composed only of the structural unit (c-1). In this case, the block copolymer preferably has a block configuration of polymer block (A) -polymer block (B) -polymer block (C).

  Examples of the alkenyl aromatic compound in the structural unit (c-1) include the same compounds as the alkenyl aromatic compound in the structural unit (b-2), and preferred compounds are also the same.

1.1.4. Block Configuration In the block copolymer, the mass conversion ratio ((A) / (B)) of the polymer block (A) and the polymer block (B) is usually from 5/95 to 50/50. / 90 to 40/60 is preferable. From the viewpoint of pellet moldability, the ratio of the polymer block (A) is preferably 5 or more and the ratio of the polymer block (B) is preferably 95 or less. On the other hand, from the viewpoint of fluidity during processing, the ratio of the polymer block (A) is preferably 50 or less, and the ratio of the polymer block (B) is preferably 50 or more.

  When the block copolymer further includes a polymer block (C), the polymer block (A) and the ratio in terms of mass of the polymer block (B) and the polymer block (C) ({(A) + (B )} / (C)) is usually 80/20 to 99/1, preferably 85/15 to 95/5. When the ratio of the polymer block (C) exceeds 20, workability at the time of melting may be impaired.

  In the block copolymer, the content ratio of the structural unit derived from the alkenyl aromatic compound is preferably 30% by mass or less based on the block copolymer from the viewpoint of maintaining fluidity during the molding of the nonwoven fabric. More preferably, it is 20-5 mass%. Here, the content ratio of the structural unit derived from the alkenyl aromatic compound is, for example, that of the structural unit (b-2) in the polymer block (B) and the structural unit (c-1) in the polymer block (C). Refers to the total content (of course, either may not be included).

  A functional group may be introduced into the conjugated diene (co) polymer by the method described below. When a functional group is introduced into the conjugated diene-based (co) polymer, it is preferably introduced into the polymer block (C) from the viewpoint of productivity and sufficient effect of the functional group.

  The structure of the block copolymer in the conjugated diene (co) polymer may be any structure as long as it satisfies the above requirements, and examples thereof include structures represented by the following structural formulas (1) to (6). .

Structural formula (1): (AB) n1
Structural formula (2): (AB) n2-A
Structural formula (3): (BA) n3-B
Structural formula (4): (ABC) n4
Structural formula (5): A- (B-C) n5
Structural formula (6): (AB) n6-C

  In structural formulas (1) to (6), A represents a polymer block (A), B represents a polymer block (B), C represents a polymer block (C), and n1 to n6 are 1 or more. Indicates an integer.

  Here, in the block copolymers represented by the structural formulas (1) to (6), at least one of the polymer block (A), the polymer block (B), and the polymer block (C) is 2 or more. When present, each polymer block may be the same or different.

  The block copolymer has a structure in which the copolymer block is extended or branched via a coupling agent residue, such as the structures represented by the following structural formulas (7) to (12). It may be.

Structural formula (7): (AB) mX
Structural formula (8): (BA) mX
Structural formula (9): (ABA) mX
Structural formula (10): (BAB) mX
Structural formula (11): (ABC) mX
Structural formula (12): (ABC) X (CB)

  In structural formulas (7) to (12), A represents the polymer block (A), B represents the polymer block (B), C represents the polymer block (C), and m represents an integer of 2 or more. And X represents a coupling agent residue. In the above structure example, a structure surrounded by parentheses and having X indicates that the block closest to X in the parentheses is directly bonded to X. For example, (ABC) mX indicates that m (ABC) are directly bonded to X by the polymer block (C).

  The structure of the block copolymer is preferably a structure represented by the structural formula (1), (3), (4) or (7) among the structures represented by the structural formulas (1) to (12). .

  The coupling rate in the block copolymer is preferably 50 to 90% in consideration of processability during molding. In addition, let the ratio by which a molecule | numerator is connected through a coupling agent be a coupling rate.

  Examples of the coupling agent include 1,2-dibromoethane, methyldichlorosilane, dimethyldichlorosilane, trichlorosilane, methyltrichlorosilane, tetrachlorosilane, tetramethoxysilane, divinylbenzene, diethyl adipate, dioctyl adipate, benzene- 1,2,4-triisocyanate, tolylene diisocyanate, epoxidized 1,2-polybutadiene, epoxidized linseed oil, tetrachlorogermanium, tetrachlorotin, butyltrichlorotin, butyltrichlorosilane, dimethylchlorosilane, 1,4 -Chloromethylbenzene, bis (trichlorosilyl) ethane.

  The block copolymer can be produced, for example, by the method described in Japanese Patent No. 3134504 and Japanese Patent No. 3360411.

  As the block copolymer, the above block copolymers can be used alone, or two or more block copolymers can be mixed and used. Examples of combinations of block copolymers include ABA / AB, (AB) 2-X / AB, (AB) 4-X / AB, (A- B) 4-X / (AB) 2-X / AB, (AB) 4-X / (AB) 3-X / (AB) 2-X / AB, A-B-C / A-B, (A-B-C) 2 / A-B, (A-B-C) 2-X / A-B (where A represents the polymer block (A)) , B represents a polymer block (B), C represents a polymer block (C), and X represents a coupling agent residue.

  When the conjugated diene (co) polymer is hydrogenated (such a conjugated diene (co) polymer is also referred to as a “hydrogenated diene (co) polymer”), a hydrogenated diene (co) ) Polymers can be used alone or in combination of two or more hydrogenated diene (co) polymers. Examples of combinations of hydrogenated diene-based (co) polymers include: A-B-A hydrogenated product / A-B hydrogenated product, (A-B) 2-X hydrogenated product / A-B Hydrogenated product, (AB) 4-X hydrogenated product / AB hydrogenated product, (AB) 4-X hydrogenated product / (AB) 2-X hydrogenated product / A-B hydrogenated product, (AB) 4-X hydrogenated product / (AB) 3-X hydrogenated product / (AB) 2-X hydrogenated product / A -B hydrogenated product, ABC-hydrogenated product / AB-hydrogenated product, (ABC) 2 hydrogenated product / AB-hydrogenated product, (AB) -C) 2-X hydrogenated product / AB hydrogenated product (where A represents the polymer block (A), B represents the polymer block (B), and C represents the polymer block (C ) And X represents a coupling agent residue.

1.1.5. Physical properties of conjugated diene-based (co) polymers Conjugated diene-based (co) polymers have a weight average molecular weight (hereinafter also referred to as “Mw”) in terms of polystyrene by gel permeation chromatography (GPC) method of 10,000 to 70. It is preferably 10,000, more preferably 100,000 to 500,000, and particularly preferably 200,000 to 500,000. From the viewpoint of preventing blocking at the time of pelletization and obtaining the mechanical strength of the nonwoven fabric, Mw is preferably 10,000 or more, and Mw is 700,000 or less to ensure fluidity during processing. It is preferable.

  The conjugated diene-based (co) polymer preferably has a melting peak in the range of 70 to 140 ° C., and has a melting peak in the range of 80 to 120 ° C. when measured by differential scanning calorimetry (DSC method). It is more preferable to have.

The value of the melt flow rate (hereinafter also referred to as “MFR”) of the conjugated diene-based (co) polymer is not particularly limited, but is generally preferably 0.01 to 100 g / 10 min. In addition, in this specification, MFR is the value measured by 230 degreeC and the load of 98.1N based on JISK7210.

1.1.6. Method for producing hydrogenated diene-based (co) polymer In the present embodiment, the conjugated diene-based (co) polymer is preferably hydrogenated. The hydrogenated diene-based (co) polymer is a copolymer having a double bond hydrogenation rate derived from a conjugated diene compound of 90% or more in order to satisfy shape retention and mechanical properties. It is preferable that the copolymer is 95% or more.

  The method for producing the hydrogenated diene-based (co) polymer is not particularly limited, and can be produced by preparing the block copolymer and then hydrogenating the prepared block copolymer. The block copolymer is obtained by, for example, subjecting the first conjugated diene compound to living anion polymerization using an organic alkali metal compound as a polymerization initiator in an inert organic solvent, and then the second conjugated diene compound and optionally an alkenyl aromatic. The compound can be further produced by conducting living anion polymerization and, if necessary, further adding an alkenyl aromatic compound and conducting living anion polymerization.

  Examples of the inert organic solvent include aliphatic hydrocarbon solvents such as pentane, hexane, heptane, and octane; alicyclic hydrocarbon solvents such as cyclopentane, methylcyclopentane, cyclohexane, and methylcyclohexane; benzene, xylene, toluene, An aromatic hydrocarbon solvent such as ethylbenzene can be used.

  In addition, when a coupling agent residue is introduced into the block copolymer, the second conjugated diene compound can be easily reacted by adding a coupling agent without performing an operation such as isolation after living anion polymerization. Can be introduced.

  In the living anionic polymerization, the vinyl bond content of the polymer block (B) is the ether compound, tertiary amine, alkali metal (sodium, potassium, etc.) alkoxide, phenoxide, sulfonate, etc. Etc. can be easily controlled by appropriately selecting them.

  By hydrogenating this block copolymer, a hydrogenated diene-based (co) polymer can be easily prepared. There are no particular limitations on the hydrogenation method and reaction conditions of the block copolymer, and the reaction is usually carried out in the presence of a hydrogenation catalyst at 20 to 150 ° C. under a hydrogen pressure of 0.1 to 10 MPa. In this case, the hydrogenation rate can be arbitrarily selected by changing the amount of the hydrogenation catalyst, the hydrogen pressure during the hydrogenation reaction, or the reaction time.

  Examples of the hydrogenation catalyst include JP-A-1-275605, JP-A-5-271326, JP-A-5-271325, JP-A-5-222115, JP-A-11-292924, and JP-A-11-292924. JP 2000-37632 A, JP 59-133203 A, JP 63-5401 A, JP 62-218403 A, JP 7-90017 A, JP 43-19960 A, Examples thereof include the hydrogenation catalyst described in JP-B 47-40473. In addition, the said hydrogenation catalyst may be used only 1 type, and can also use 2 or more types together.

  After hydrogenation, the catalyst residue is removed as necessary, or a phenol-based or amine-based antioxidant is added, and then the hydrogenated diene (co) polymer solution is added to the hydrogenated diene (co). The polymer is isolated. Isolation of the hydrogenated diene-based (co) polymer can be performed, for example, by adding acetone or alcohol to the hydrogenated diene-based (co) polymer solution to cause precipitation, It can be carried out by, for example, a method in which the solvent is added with stirring and the solvent is distilled off.

  Since the polymer block (A) is a polymer block having a vinyl bond content of less than 30 mol%, a structure similar to polyethylene is obtained by hydrogenation, for example, when the first conjugated diene compound is 1,3-butadiene. Thus, a polymer block with good crystallinity is obtained. Since the polymer block (B) is a polymer block having a vinyl bond content of 30 mol% or more, the polymer block (B) is subjected to hydrogenation, for example, when the second conjugated diene compound is 1,3-butadiene. In this case, the rubber-like ethylene-butylene copolymer has a similar structure and a soft polymer block. Therefore, for example, when the first and second conjugated diene compounds are 1,3-butadiene, the hydrogenated diene-based (co) polymer has an olefin crystal-ethylene / butylene-olefin crystal block polymer structure. By using the hydrogenated diene-based (co) polymer having such a structure, an effect of excellent fluidity at the time of molding can be obtained.

1.1.7. Modification of Conjugated Diene (Co) polymer In the present invention, the conjugated diene (co) polymer is modified with a functional group from the viewpoint of imparting a desired function such as liquid retention to the separator to the separator. It may be. Examples of the functional group include those described as the functional group group X below. It does not specifically limit as a method to introduce | transduce a functional group, For example, the method described in the following manufacturing method (a)-(e) is employable. Details of these methods can be referred to the descriptions in Japanese Patent No. 5272728, International Publication No. 2014/014052, and the like.

[Functional group group X]:
Carboxyl group, acid anhydride group, epoxy group, (meth) acryloyl group, amino group, alkoxysilyl group, hydroxyl group, isocyanate group and oxazoline group

<Production method (a)>
A conjugated diene compound alone, or a conjugated diene compound and an alkenyl aromatic compound are copolymerized in the presence of an organic alkali metal compound or an organic alkaline earth metal compound, and the copolymer is hydrogenated as necessary. The diene polymer obtained in this manner is reacted with a compound having the following functional group in a solution or a kneader such as an extruder.

<Production method (b)>
A method of copolymerizing a conjugated diene compound alone or a conjugated diene compound and an alkenyl aromatic compound in the presence of an organic alkali metal compound having an amino group, and then hydrogenating the copolymer as necessary.

<Production method (c)>
After copolymerizing a conjugated diene compound alone or a conjugated diene compound and an alkenyl aromatic compound with an unsaturated monomer having the following functional group in the presence of an organic alkali metal compound or an organic alkaline earth metal compound: A method of hydrogenating the polymer as required.

<Production method (d)>
Block copolymerization of a conjugated diene compound alone or a conjugated diene compound and an alkenyl aromatic compound in the presence of an organic alkali metal compound, and reacting a compound having the following functional group at the active point of the obtained copolymer And then hydrogenating the polymer as necessary.

<Production method (e)>
A copolymer obtained by polymerizing a conjugated diene compound and a specific alkenyl aromatic compound, or a conjugated diene compound, a specific aromatic alkenyl compound and another monomer, and at least one organic alkali metal compound; A method of reacting a modifying agent in the presence of at least one aliphatic amine compound.

  When the conjugated diene (co) polymer is modified with a functional group, the conjugated diene (co) polymer has an average of 0.01 to 100 (pieces / molecule) of the functional group. It is preferable that the polymer has an average of 0.1 to 10 (pieces / molecule). From the viewpoint of obtaining compatibility with the electrolytic solution, the number of functional groups is preferably 0.01 (number / molecule) or more on average. On the other hand, from the viewpoint of maintaining the fluidity and workability of the resin composition, the number of functional groups is preferably 100 (pieces / molecule) or less.

1.2. Thermoplastic resin The thermoplastic resin used in the present embodiment is not particularly limited, and polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), acrylic resin (PMMA), polystyrene, AS resin, Styrenic resin such as ABS resin, nylon 6,6 (PA66), nylon 12 (PA12), polyamide (PA) such as modified polyamide, polyolefin, polycarbonate (PC), polyacetal (POM), fluororesin (FR), modified Polyphenylene ether (modified PPE), polyphenylene sulfide (PPS), polyester elastomer (TPC, formerly TPEE), polyarylate (PAR), liquid crystal polymer (fully aromatic, semi-aromatic) (LCP), polysulfone (PSU), Poly Ethersulfone (PESU), polyetheretherketone (PEEK), polyetherimide (PEI), polyamideimide (PAI), polyimide (PI) are exemplified, and one or more selected from these may be used in combination Can do.

  From the viewpoint of hydrophilicity, polyamide is preferred. From the viewpoint of heat resistance, polyphenylene sulfide is preferable. From the viewpoint of excellent acid resistance, polyester, polyolefin, acrylic, aramid, etc., alone or in combination are preferred. In particular, those having durability against alkaline or acidic liquids such as electrolytic solutions are also preferred. For example, from the viewpoint of excellent alkali resistance, polyolefins, polyamides, aramids, etc., alone or in combination are preferred.

  In the present embodiment, polyolefin is most preferable from the viewpoints of chemical stability with respect to the electrolyte, compatibility with the conjugated diene (co) polymer, processability, and the like. Hereinafter, the polyolefin used in the present embodiment will be described in detail.

  Examples of the monomer constituting the polyolefin include homopolymers of α-olefins having about 2 to 8 carbon atoms such as ethylene, propylene, and 1-butene; these α-olefins, ethylene, propylene, and 1-butene. 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, 1-octene And binary or ternary copolymers with other α-olefins having about 2 to 18 carbon atoms such as 1-decene and 1-octadecene. As the monomer raw material, for example, either a petroleum-derived raw material or a plant-derived raw material such as sugar cane may be used.

  The polymerization method is not particularly limited, and the polymerization method may be obtained by any one of a polymerization method using a Ziegler-Natta catalyst and a polymerization method using a metallocene catalyst. There is no restriction | limiting in particular about the polymerization method, For example, the polymer obtained by superposing | polymerizing by a conventionally well-known polymerization method (Example: high pressure method, low pressure method) etc. can be used.

More specifically, for example, ethylene homopolymers such as branched low-density polyethylene and linear high-density polyethylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-propylene-1-butene Polyethylene such as copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-heptene copolymer, ethylene-1-octene copolymer; Polypropylene such as a polymer, propylene-ethylene copolymer, propylene-ethylene-1-butene copolymer; 1 such as 1-butene homopolymer, 1-butene-ethylene copolymer, 1-butene-propylene copolymer -Butene resin; 4-methyl-1-pentene homopolymer, 4-methyl-1-pentene-ethylene copolymer, etc. - a resin such as pentene resins.

  Further, α-olefin, 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 6-methyl-1,5-heptadiene, 1,4-octadiene, 7 -Methyl-1,6-octadiene, cyclohexadiene, cyclooctadiene, dicyclopentadiene, 5-methylene-2-norbornene, 5-ethylidene-2-norbornene, 5-butylidene-2-norbornene, 5-isopropenyl-2 -Binary or ternary copolymers with non-conjugated dienes such as norbornene. Examples of the ternary copolymer include an ethylene-propylene-nonconjugated diene copolymer and an ethylene-1-butene-nonconjugated diene copolymer.

  Among these, polypropylene is preferable from the viewpoint that the structure of the separator can be maintained and the strength at the time of battery assembly can be obtained when the battery is exposed to a high temperature due to a short circuit or overcharge. Polyethylene is preferable from the viewpoint of imparting a property of melting at an appropriate temperature (for example, around 130 ° C.) when the battery abnormally generates heat due to a short circuit or the like and closing the porous structure (shutdown). From the viewpoint of compatibility with the conjugated diene-based (co) polymer, polyethylene and polypropylene are preferable, polypropylene is more preferable, propylene-ethylene copolymer and propylene homopolymer (homopolypropylene) are more preferable, Propylene homopolymer is most preferred.

  Two or more of these polyolefins may be used in combination. For example, when polyethylene and polypropylene are used in combination, the composition ratio of polyethylene and polypropylene is not particularly limited, and may be determined according to the resin characteristics desired to be imparted to the separator. The composition ratio of polyethylene and polypropylene is preferably, for example, 10:90 to 90:10, and more preferably 30:70 to 70:30. As another polyolefin combination, for example, the above-mentioned crystalline polyolefin and amorphous polyolefin can be used in combination. Examples of the amorphous polyolefin include homopolymers such as atactic polypropylene and atactic poly-1-butene; copolymers of propylene (containing 50 mol% or more) and other α-olefins (illustrated above), Examples include copolymers of 1-butene (containing 50 mol% or more) and other α-olefins (illustrated above).

  The weight average molecular weight (Mw) of the thermoplastic resin is preferably 30,000 to 70,000, and more preferably 40,000 to 60,000. By setting the weight average molecular weight to 30,000 or more, yarn breakage can be suppressed in the spinning process, and the spinning tension can be set higher, whereby stable spinnability can be obtained. Accordingly, fibers having excellent mechanical properties can be obtained. Further, by setting the weight average molecular weight to 70,000 or less, it is possible to suppress the melt viscosity of the thermoplastic resin in the melt spinning process and to suppress the manufacturing equipment cost. The molecular weight distribution (Mw / Mn) is not particularly limited, but is usually 1 or more, preferably 2 or more, and is usually 10 or less, preferably 7 or less, more preferably 5 or less.

1.3. Other components In addition to the above components, as other additives, stabilizers such as aging (oxidation) inhibitors, weathering agents, metal deactivators, light stabilizers, UV absorbers, heat stabilizers, antibacterial / antifungal agents Agent, conductivity enhancer, dispersant, softener, plasticizer, crosslinking agent, co-crosslinking agent, vulcanizing agent, vulcanization aid, foaming agent, foaming aid, colorant, flame retardant, vibration damping agent, deodorant One or two or more selected from agents, lubricants and the like may be added. Moreover, it is preferable to use an inorganic filler for the purpose of improving insulation and heat shrinkability. The method of adding these other components to the nonwoven fabric is not particularly limited. For example, the nonwoven fabric may be produced by blending in advance in the composition and then the melt-blow method described later, and by operations such as coating, spraying, and dipping on the nonwoven fabric. You may go.

  Examples of inorganic fillers include hydroxides such as magnesium hydroxide, aluminum hydroxide, zirconium hydroxide, calcium hydroxide, barium hydroxide; basic magnesium carbonate, dolomite, hydrotalcite, tin oxide, titanium oxide, oxidation Oxides such as zinc, iron oxide, magnesium oxide, and alumina; sulfides such as barium sulfate, calcium sulfate, sodium sulfate, and calcium sulfite, calcium silicate, calcium carbonate, magnesium carbonate, phosphate compounds, glass beads, glass powder Asbestos, mica, talc, silica, zeolite, kaolin, quartz sand, quartzite, quartz powder and shirasu. Among these inorganic fillers, silica, titanium oxide, mica, and the like are preferable from the viewpoint of improving electrical insulation and reinforcing effect.

In addition, the average particle size of the inorganic filler is preferably 0.1 to 50 μm from the viewpoint of fiber refining from a composition with a synthetic resin described later and moldability of the nonwoven fabric, and the amount of the inorganic filler used is In the case where an inorganic filler film is formed on the nonwoven fabric by operations such as coating, spraying, and dipping, a range of 0.5 to 10 g / m ² is exemplified from the viewpoint of productivity of the separator. The average particle diameter of the inorganic filler can be measured according to JIS Z8825: 2013, particle diameter analysis-laser diffraction / scattering method.

  After the inorganic filler film is formed on the nonwoven fabric, the inorganic filler surface is sandwiched between the nonwoven fabrics in the form of a sandwich. It can be set as the nonwoven fabric fuse | fused and laminated | stacked by.

  The nonwoven fabric which concerns on this Embodiment is good also as a nonwoven fabric for electrical storage device separators using together with the nonwoven fabric which consists of components other than the above. Examples of fibers that can be preferably used in combination include semi-aromatic polyamide fibers, wholly aromatic polyamide fibers, glass fibers, and mixtures of glass fibers and organic fibers. Among these, semi-aromatic polyamide fibers are more preferable. The semi-aromatic polyamide fiber is a fiber made of a semi-aromatic polyamide obtained by condensing an aromatic dicarboxylic acid and an aliphatic diamine as a main component, and 60 mol% or more of the dicarboxylic acid component is an aromatic dicarboxylic acid, 60 mol% or more of the diamine component is an aliphatic alkylenediamine having 6 to 12 carbon atoms. Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3 -Phenylenedioxydiacetic acid, 2,2'-biphenyldicarboxylic acid, 2,4'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-oxydibenzoic acid, diphenylmethane-4,4'- Dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid is used. Examples of the aliphatic diamine include 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, and 2-methyl. -1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2 -Methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine and the like.

1.4. Ratio of each component The content ratio of the thermoplastic resin in the nonwoven fabric according to the present embodiment is 70% by mass or more and 99% by mass when the total amount of the conjugated diene (co) polymer and the thermoplastic resin is 100% by mass. % Or less, more preferably 75% by mass or more and 95% by mass or less, and particularly preferably 80% by mass or more and 90% by mass or less. From the viewpoint of maintaining strength, workability, and roll drawability, it is preferably 70% by mass or more. From the viewpoint of obtaining flexibility and impact resistance, it is preferably 99% by mass or less.

1.5. Manufacturing method Although the manufacturing method of the nonwoven fabric which concerns on this Embodiment is not specifically limited, For example, it can obtain as follows.

  As a method for obtaining the composition from each of the above components, a conventionally known kneader such as a single screw extruder, a twin screw extruder, a Banbury mixer, a kneader, a roll, or a kneader formed by combining them is used as necessary. And a method of kneading the other optional components. In kneading, a method of kneading each component at once or a multistage divided kneading method in which a certain component is kneaded and then the remaining components are added and kneaded can be employed. As a specific method, for example, a method described in JP 2014-19745 A can be mentioned.

  The nonwoven fabric which concerns on this Embodiment can be obtained by shape | molding said composition into a nonwoven fabric. The production method is not particularly limited, and the wet papermaking method in which the fibers are uniformly suspended in water and then raked into a sheet shape with a wire mesh, etc .; the card method, airlaid method, and cross layer that are collected after the fibers are scattered in the air It can be formed by a known method such as a dry method such as a method, a random weber method; a spunbond method in which a nonwoven fabric is formed simultaneously with spinning, a melt blown method (melt blow method), or a flash spinning method. The wet papermaking method is preferable from the viewpoint that the production speed is high, fibers having different fiber diameters or a plurality of types of fibers can be mixed at an arbitrary ratio in the same apparatus, and the formation is uniform. From the viewpoint that a fine fiber nonwoven fabric can be directly produced from the composition, it is preferably produced by a melt blow method.

  In the melt-blowing method, a composition is melted using a plurality of extruders, guided to the same die, and then discharged from different nozzles, hot air is blown from the periphery of the die, and the fiber diameter of the composition discharged by the hot air It is manufactured by forming a web by thinning and blowing it, and then spraying and collecting it on a net conveyor arranged at an appropriate position. At this time, the fiber fixing degree can be adjusted by appropriately setting the collection distance between the base and the net conveyor. Further, by appropriately adjusting the discharge amount of the composition, hot air temperature, hot air flow rate, conveyor moving speed, etc., the fiber orientation, fiber diameter, and nonwoven fabric weight can be arbitrarily set.

  The nonwoven fabric obtained is immediately heat-treated with a hot air dryer, felt calender, hot roll, etc., and part or all of the heat-bonded fiber is heat-melted to provide sufficient strength and compression resistance for the electricity storage device separator. Can be granted. Moreover, a high-strength nonwoven fabric can be obtained by making the fiber web collide with the fiber web and entangle the fibers three-dimensionally and then performing the heat treatment. Moreover, you may give raising process, such as a puffing process and a brushing process, to the at least one surface of the obtained nonwoven fabric.

  In the present invention, a plurality of nonwoven fabric layers may be laminated. For example, from the standpoint of spunbond nonwoven fabric layer / meltblown nonwoven fabric layer, mechanical properties, separation performance, etc., and curling due to shrinkage difference between layers, a meltblown nonwoven fabric layer / spunbond nonwoven fabric layer / meltblown nonwoven fabric layer, Or it is good also as a separator which consists of a three-layer laminated body like a spunbond nonwoven fabric layer / melt blown nonwoven fabric layer / spunbond nonwoven fabric layer.

1.6. Fiber Length, Thickness, and Hole Diameter The fibers constituting the nonwoven fabric according to the present embodiment desirably have a fiber diameter of 1 to 30 μm and a fiber length of 1 to 50 mm. The fiber diameter is preferably 1 μm or more from the viewpoint of maintaining the breathability of the nonwoven fabric. From the viewpoint of preventing the specific surface area from decreasing and the liquid retaining property from being insufficient, it is preferably 30 μm or less. Further, the fiber length is preferably 1 mm or more from the viewpoint of obtaining the strength of the nonwoven fabric, and the fiber length is preferably 50 mm or less from the viewpoint of maintaining the uniformity of the nonwoven fabric.

The basis weight of the nonwoven fabric according to the present embodiment is preferably in the range of 20 g / m ^{2 to} 100 g / m ² , and the thickness is preferably in the range of 60 μm to 250 μm. The basis weight and thickness of the nonwoven fabric for the electricity storage device separator can be appropriately selected according to the characteristics of the electricity storage device to be applied. Here, the basis weight represents the basis weight defined in JIS P8124, and the thickness represents the thickness defined in JIS P8118. The thickness can be adjusted by super calendering or thermal calendering as necessary.

  The maximum pore diameter of the nonwoven fabric according to the present embodiment is preferably in the range of 1 μm or more and 50 μm or less. From the viewpoint of maintaining the breathability and ionic conductivity of the nonwoven fabric, the maximum pore diameter is preferably 1 μm or more. From the viewpoint of preventing short circuit and maintaining the yield during battery production, the maximum pore diameter is preferably 50 μm or less. Here, the maximum pore diameter represents the maximum pore diameter according to the bubble point method defined in JIS K3832.

  In this Embodiment, in order to provide arbitrary properties to a separator, it can be set as a composite fiber. As the composite fiber, a sheath-core structure is preferable, and it is preferable to use a core-sheath type composite fiber in which the sheath is composed of a low melting point component and the core is composed of a high melting point component. Among them, the core-sheath type composite fiber in which the core component is made of polypropylene and the sheath component is made of polyethylene is preferably used because it is made of a polyolefin-based component and has excellent alkali resistance. Moreover, the cross-sectional shape of the fiber can be appropriately changed from the viewpoint of improving the liquid retention of the electrolytic solution. The cross-sectional shape of the fiber is not particularly limited, and a circular shape, an elliptical shape, a triangular shape, a star shape, a T shape, a U shape, a Y shape, a leaf shape, or the like can be used. Moreover, what has a space | gap in a fiber, what has a branched structure, etc. can also be used.

1.7. Hydrophilic treatment When a non-polar resin such as polyolefin resin is used for the nonwoven fabric according to the present embodiment, a hydrophilic treatment is performed to prevent a decrease in affinity with the electrolyte due to the hydrophobicity of the resin. You can also. Hydrophilic treatment is performed by spraying, dipping, etc., covering the nonwoven fabric with a hydrophilic agent, using it together with hydrophilic fibers, hydrophilic monomer grafting, ozone treatment, corona discharge treatment, surfactant application treatment. Sulfonation treatment, fluorination treatment, and the like, and at least one hydrophilization treatment selected from these can be performed.

1.8. Applications The separator nonwoven fabric for an electricity storage device according to the present embodiment is an electricity storage device such as a primary battery, a secondary battery, a lithium ion capacitor, an electric double layer capacitor, particularly a nickel-cadmium battery, a nickel-zinc battery, a nickel-hydrogen battery, etc. In addition to small-sized electronic devices such as mobile phones, notebook computers, audio devices, etc., and small power applications such as electric tools and electric bicycles, large vehicles such as hybrid vehicles and electric vehicles Can be widely used for power applications.

2. Examples Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples. In addition, unless otherwise indicated, the part and% in an Example are a mass reference | standard. Various measurements in the examples were based on the following methods.

2.1. Physical property evaluation of conjugated diene (co) polymers <Vinyl bond content>
The vinyl bond content of the conjugated diene (co) polymer was calculated by the Hampton method using infrared analysis.

<Weight average molecular weight>
The weight average molecular weight was determined in terms of polystyrene using gel permeation chromatography [GPC, column; manufactured by Tosoh Corporation, GMHHR-H].

<Hydrogenation rate>
The hydrogenation rate of the conjugated diene was calculated from a 100 MHz, ¹ H-NMR spectrum using ethylene tetrachloride as a solvent.

<Melt flow rate (MFR)>
The MFR was determined by measuring at 230 ° C. and a load of 98.1 N according to JIS K7210.

<Bound styrene content>
Calculation was performed from 270 MHz, ¹ H-NMR spectrum using carbon tetrachloride as a solvent.

<Functional group content (individual / polymer)>
“Functional group content” means the ratio of functional groups in the polymer and can be represented by the following formula (1).
Functional group content = functional group (pieces) / polymer (single molecular chain) (1)
Regarding this functional group content, Analy. Chem. Quantified in accordance with the amine titration method described in 564 (1952). That is, the obtained conjugated diene-based (co) polymer was dissolved in an organic solvent, methyl violet was used as an indicator, and HClO ₄ / CH ₃ COOH was added dropwise until the color of the solution changed from purple to light blue. The functional group content was calculated from the amount dropped.

2.2. Physical property evaluation of nonwoven fabric for electricity storage device separator
A 50 mm × 200 mm sample was measured with an electronic balance up to three digits after the decimal point, and converted to a mass per unit area of 1 m ² .

<Tensile strength>
A 50 mm × 200 mm sample was measured by a method according to JIS P8113.

<Puncture strength>
A sample was prepared by cutting a nonwoven fabric for an electricity storage device separator into an arbitrary size having a width of 50 mm or more and a length of 200 mm or more. This was put into a constant temperature dryer (DHS82 manufactured by Yamato Scientific Co., Ltd.) and heat-treated at 250 ° C. for 50 hours. Thereafter, the strips were cut into strips having a width of 50 mm. Attach a 1 mm diameter metal needle (Orientec Co., Ltd.) with a rounded end (curvature 1.6) to the desktop material testing machine (Orientec Co., Ltd. STA-1150) and place it on the sample surface. On the other hand, it was lowered until it penetrated at a constant speed of 1 mmZs at a right angle. The maximum load (N) at this time was measured and used as the puncture strength. One sample was measured at five or more locations, and the lowest puncture strength among all the measured values is shown in Table 1.

<Bending strength test (winding flexibility)>
A non-woven fabric piece for an electricity storage device separator cut out to 4.5 cm × 4 cm was bent with a spacer in between, and the bent portion was uniformly loaded from above, and then the bent portion was observed with an SEM. In SEM observation, the convex part of the fold line was observed at a magnification of 100 times to confirm the presence or absence of cracks. The bending test was performed on three samples cut out from the separators of each of the examples and comparative examples, and the bending strength when no cracks were confirmed in all the fields of view observed in the three tests was as follows. The bending strength of each separator was evaluated with x as the bending strength when confirmed. In this test, the thickness of the spacer sandwiching the separator piece was set to 300 μm, assuming the R portion of the innermost circumference of the electrode group when the separator was applied to a wound electrode group.

<Processability>
Processability by melt blow was evaluated according to the following criteria.
A: Good workability, and a good nonwoven fabric was obtained under a wide range of conditions. ○: A nonwoven fabric could be obtained under normal conditions without any problem in workability. X: Low fluidity during melting, or Uniform non-woven fabric cannot be obtained under normal conditions, for example, the ejected fibers are aggregated and glued.

<Roll pullability>
The roll drawability of the roll-wrapped nonwoven fabric was evaluated by the following criteria for the stability of peeling between the nonwoven fabric and the nonwoven fabric when the roll-wrapped nonwoven fabric was set on a freely rotating shaft and pulled at a speed of 10 m / min.
(Double-circle): It pulled out without a problem.
○: Although some parts of the peeling were unstable, they could be pulled out without any problem.
X: Due to sticking between the nonwoven fabrics, peeling was unstable and could not be pulled out.

2.3. Synthesis of conjugated diene-based (co) polymer <Synthesis Example 1: Synthesis of hydrogenated conjugated diene copolymer (H1)>
24000 g of cyclohexane, 1.3 g of tetrahydrofuran, 570 g of 1,3-butadiene and 2.4 g of n-butyllithium were added to a reaction vessel having an internal volume of 50 L purged with nitrogen, and polymerized at a polymerization start temperature of 70 ° C. After completion of the reaction, the temperature was 35 ° C., 210 g of tetrahydrofuran was added, and then adiabatic polymerization was carried out while successively adding 3230 g of 1,3-butadiene. Thereafter, 1.5 g of methyldichlorosilane was added to the system and reacted for 30 minutes to synthesize a block copolymer.

  The block copolymer includes a structural unit derived from 1,3-butadiene, includes a polymer block (A) having a vinyl bond content of 16 mol%, and a structural unit derived from 1,3-butadiene. It was a block copolymer having a polymer block (B) having a bond content of 68 mol%. Moreover, in the said block copolymer, the weight average molecular weight was 380,000 and the coupling rate was 75%.

  Subsequently, the reaction solution containing the block copolymer is brought to 80 ° C., 2.5 g of bis (cyclopentadienyl) titanium furfuryloxychloride and 1.2 g of n-butyllithium are added, and the hydrogen pressure is maintained at 1.0 MPa. For 2 hours.

  After the reaction, the reaction solution was returned to room temperature and normal pressure, extracted from the reaction vessel, stirred into water, and the solvent was removed by steam distillation to obtain the desired hydrogenated conjugated diene copolymer (H1). . The hydrogenation rate of the hydrogenated conjugated diene copolymer (H1) was 98%, and the MFR was 2.3 g / 10 min.

<Synthesis Example 2: Synthesis of hydrogenated conjugated diene copolymer (H2)>
In the above synthesis example 1, the amount of 1,3-butadiene used in the polymerization reaction of the polymer blocks (A) and (B) was 900 g and 2100 g, the amount of n-butyllithium was 5.0 g, and the polymer 125 g of tetrahydrofuran used for the polymerization reaction of block (B)
A block copolymer was synthesized in the same manner as in Synthesis Example 1 except that tetrachlorosilane was used instead of methyldichloromethane.

  The block copolymer includes a structural unit derived from 1,3-butadiene, includes a polymer block (A) having a vinyl bond content of 15 mol%, and a structural unit derived from 1,3-butadiene. It was a block copolymer having a polymer block (B) having a bond content of 48 mol%. The block copolymer had a weight average molecular weight of 320,000 and a coupling rate of 79%.

<Synthesis Example 3: Synthesis of hydrogenated conjugated diene copolymer (H3)>
After charging 30,000 g of cyclohexane and 1,000 g of 1,3-butadiene in a reaction vessel having an internal volume of 50 L that is purged with nitrogen, 1.5 g of tetrahydrofuran and 4 g of n-butyllithium are added, and adiabatic polymerization from 60 ° C. is performed. 40 minutes. After completion of the reaction, the reaction solution was adjusted to 30 ° C., and 60 g of tetrahydrofuran and 3,750 g of 1,3-butadiene were added to conduct adiabatic polymerization. After the conversion rate was almost 100%, 250 g of styrene was further added to polymerize the diene copolymer. After completion of the reaction, the hydrogenation reaction and catalyst removal were performed in the same manner as in Synthesis Example 1 to obtain the desired hydrogenated conjugated diene copolymer (H3).

  The hydrogenated conjugated diene copolymer (H3) is a block copolymer having a polymer block (A) having a vinyl bond content of 14 mol% and a polymer block (B) having a vinyl bond content of 42 mol%. there were. When the molecular properties of the hydrogenated conjugated diene copolymer (H3) were measured, the bound styrene content of the polymer before hydrogenation was 5 mass%, the weight average molecular weight was 140,000, MFR was 2.1 g / 10 min, and the hydrogenation rate. Was 98%.

<Synthesis Example 4: Synthesis of hydrogenated conjugated diene copolymer (H4)>
In Synthesis Example 3 above, 250 g of styrene was added to polymerize the diene copolymer, and then 17 g of N, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane was added and reacted for 30 minutes. Introduced into the active site. After completion of the reaction, the hydrogenation reaction and catalyst removal were carried out in the same manner as in Synthesis Example 1 to obtain the desired hydrogenated conjugated diene copolymer (H4).

  The hydrogenated conjugated diene copolymer (H4) is a block copolymer having a polymer block (A) having a vinyl bond content of 14 mol% and a polymer block (B) having a vinyl bond content of 42 mol%. there were. When the molecular characteristics of the hydrogenated conjugated diene copolymer (H4) were measured, the bound styrene content of the polymer before hydrogenation was 5 mass%, the weight average molecular weight was 140,000, the MFR was 2.4 g / 10 min, and the functional group content. Was 0.88 / polymer, and the hydrogenation rate was 98%.

4.4. Examples 1-10, Comparative Examples 1-2
<Example 1>
The mixed raw materials having the composition shown in Table 1 below are pre-dried, melted with an extruder, and then fed to a melt blow spinning apparatus having orifices with a diameter of 0.3 mm arranged in a 1 mm pitch and slits for jetting heated gas, Melt blow spun. At this time, the temperature of the melt-blowing device was set to 260 ° C., the discharge rate of the resin composition per hole was set to 0.1 g / min, and the air heated to 260 ° C. was supplied from the gas injection slit to the resin. Injected at a speed 43 times the weight of the discharge speed. The fibers from the nozzle are collected on a wire mesh belt conveyor installed below the nozzle to form a nonwoven fabric having a basis weight of 40 g / m ² , and then wound into a roll with a winder, and the nonwoven fabric for an electricity storage device separator Got. The evaluation results of each test on the obtained nonwoven fabric are shown in Table 1 below.

<Examples 2 to 10, Comparative Examples 1 and 2>
A nonwoven fabric for an electricity storage device separator was obtained in the same manner as in Example 1 except that the raw materials were those listed in Table 1 below. Table 1 below shows the evaluation results of the fineness and physical properties of the obtained nonwoven fabric.

In Table 1, abbreviations indicate the following compounds, respectively.
CEBC1: hydrogenated conjugated diene copolymer (H1) obtained in Synthesis Example 1 above
CEBC2: hydrogenated conjugated diene copolymer (H2) obtained in Synthesis Example 2 above
SEBC: hydrogenated conjugated diene copolymer (H3) obtained in Synthesis Example 3 above
SEBC-f: hydrogenated conjugated diene copolymer (H4) obtained in Synthesis Example 4
-EPDM: JSR Co., Ltd. JSR EP103AF
・ LLDPE: "Novatec LL UJ990" (linear low density polyethylene), manufactured by Nippon Polyethylene
-Homo-PP: Nippon Polypro's homotype polypropylene "Novatec SA06GA" (trade name)
-PA: nylon 6 "Amilan CM1017" (trade name) manufactured by Toray Industries, Inc.

  The present invention is not limited to the above embodiment, and various modifications can be made. The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). The present invention also includes a configuration in which a non-essential part of the configuration described in the above embodiment is replaced with another configuration. Furthermore, the present invention includes a configuration that achieves the same effects as the configuration described in the above embodiment or a configuration that can achieve the same object. Furthermore, the present invention includes a configuration obtained by adding a known technique to the configuration described in the above embodiment.

Claims (11)

A polymer block (A) containing a structural unit (a-1) derived from the first conjugated diene compound and having a vinyl bond content of less than 30 mol%, and a structural unit derived from the second conjugated diene compound (b -1) and a conjugated diene (co) polymer having a polymer block (B) having a vinyl bond content of 30 mol% or more,
A thermoplastic resin;
A nonwoven fabric for an electricity storage device separator, characterized by comprising a nonwoven fabric containing   The first conjugated diene compound is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene. The nonwoven fabric for electrical storage device separators of Claim 1 which is at least 1 sort (s) of compounds selected from the group which consists of 4,5-diethyl- 1,3-octadiene and chloroprene.   The second conjugated diene compound is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene. The nonwoven fabric for electrical storage device separators of Claim 1 or Claim 2 which is at least 1 sort (s) of compounds selected from the group which consists of 4,5-diethyl- 1,3-octadiene and chloroprene.   The content ratio of the thermoplastic resin in the nonwoven fabric is 70% by mass or more and 99% by mass or less when the total amount of the conjugated diene (co) polymer and the thermoplastic resin is 100% by mass. The nonwoven fabric for electrical storage device separators as described in any one of Claim 1 thru | or 3.   The nonwoven fabric for an electricity storage device separator according to any one of claims 1 to 4, wherein the conjugated diene-based (co) polymer is hydrogenated.   The nonwoven fabric for electrical storage device separators according to any one of claims 1 to 5, wherein the thermoplastic resin is a polyolefin.   The nonwoven fabric for an electricity storage device separator according to claim 6, wherein the polyolefin is at least one selected from the group consisting of polyethylene and polypropylene.   An electrical storage device provided with the nonwoven fabric for electrical storage device separators as described in any one of Claims 1 thru | or 7. A polymer block (A) containing a structural unit (a-1) derived from the first conjugated diene compound and having a vinyl bond content of less than 30 mol%, and a structural unit derived from the second conjugated diene compound (b -1) and a conjugated diene (co) polymer having a polymer block (B) having a vinyl bond content of 30 mol% or more,
A thermoplastic resin;
The resin composition for manufacturing the nonwoven fabric for electrical storage device separators containing this.   The first conjugated diene compound is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene. The resin composition for manufacturing the nonwoven fabric for electrical storage device separators of Claim 9 which is at least 1 sort (s) of compounds selected from the group which consists of 4,5-diethyl- 1,3-octadiene and chloroprene.   The second conjugated diene compound is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene. The resin for manufacturing the nonwoven fabric for electrical storage device separators of Claim 9 or Claim 10 which is at least 1 sort (s) of compounds selected from the group which consists of 4,5-diethyl- 1,3-octadiene and chloroprene. Composition.