JPH05190165A - Separator for battery - Google Patents

Abstract

PURPOSE:To improve the antielectrolyte performance, antioxidation performance, and strength holding performance by using a hydrophilic nonwoven fabric which contains the unsaturated copolymer resin consisting of a specific alpha- olefine and the chained type nonconjugated dienes, as basic material. CONSTITUTION:An unsaturated copolymer resin which consists of at least one kind of alpha- olefines having the number of carbon atoms of 2-12 and at least one kind of the chained type nonconjugated dienes represented by the formula I (in the formula, (n) is an integer of 1-10 and each of R<1>-R<2> is H or alkyl group having the number of carbon atoms of 8 or less) and has a diene content of 0.05-50mol% is prepared, and a nonwoven fabric having the above-described unsaturated copolymer resin as basic material is sulfonated, and the obtained hydrophilic nonwoven fabric is used as a separator. Since the unsaturated copolymer resin in the nonwoven fabric possesses the physical properties of alpha- olefin polymer, the superior mechanical strength, alkali resistance, and antioxidation characteristic are provided, and the nonwoven fabric suitable for separator can be obtained.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery separator obtained by sulfonation of a non-woven fabric made of an unsaturated copolymer resin composed of α-olefin and chain non-conjugated dienes.

[0003]

2. Description of the Related Art Portable electric appliances, office automation equipment and information appliances are rapidly becoming portable and cordless, and batteries which are power sources thereof are required to be further reduced in size and weight and to have higher performance. For this purpose, the demand for secondary batteries such as nickel-cadmium batteries that can be repeatedly used by charging is increasing. Most batteries consist of positive electrode, negative electrode, electrolyte,
It consists of a separator and a container. Various improvements have been made to each constituent element in order to improve the performance of the battery, and the separator is one of them.

The most important role of the separator in the secondary battery is to separate the positive electrode and the negative electrode to prevent an electronic short circuit. Therefore, it is required to have resistance to electrolyte solution and withstand oxidation during charging. In addition, the separator is required to retain an electrolyte solution as a characteristic, and a hydrophilic material is used to satisfy this requirement. Specifically, polyamide or a polyolefin-based non-woven fabric such as hydrophilically treated polypropylene is used. (JP-A-57-191956, same 1-
132044).

[0005]

However, although the polyamide separator has tentative alkali resistance,
The strength decreases under high temperature and for a very long time,
It is known to cause short circuits. Sulfonated polypropylene separator is excellent in terms of resistance to electrolytic solution and oxidation resistance due to polypropylene, and is preferable as a separator material for extending the life of the battery, but the sulfonation rate cannot be increased, It is desired to improve the affinity for the electrolytic solution.

An object of the present invention is to provide a battery separator excellent in electrolyte resistance, oxidation resistance and strength retention.

[0007]

The present invention has 2 to 1 carbon atoms.
2 and at least one of the chain non-conjugated dienes represented by the following formula (I), wherein the chain non-conjugated diene content is 0.05 to 5
Unsaturated copolymer resin with 0 mol%

[0008]

[Chemical 2]

(In the formula, n represents an integer of 1 to 10, and R ¹
Each of R ³ to R ³ represents a hydrophilic nonwoven fabric obtained by sulfonation of a nonwoven fabric having H or an alkyl group having 8 or less carbon atoms as a base material.

(Effect) Fibers of a copolymer of an α-olefin having 2 to 12 carbon atoms and a chain non-conjugated diene are on the surface,
Since it has an ethylenically unsaturated bond in the side chain, the sulfonation treatment is easy, and the modification degree of the sulfonation can be controlled. By sulfonation, a sulfonic acid group having a polar group can be easily introduced to the surface of the fiber, which can impart excellent hydrophilicity which is not found in conventional polyolefin-based resins to a nonwoven fabric. It is extremely useful as a separator for secondary batteries. Also,
Since the unsaturated copolymer resin of the non-woven fabric substrate has physical properties as an α-olefin polymer resin, mechanical strength,
Since it has excellent alkali resistance and oxidation resistance, it is very useful as a separator.

[0011]

[Detailed Description of the Invention]

[Detailed Description of the Invention] <Unsaturated Copolymer Resin to be Modified><GeneralDescription> The unsaturated copolymer resin used for sulfonation in the present invention has 2 to 12 carbon atoms, preferably 2 to 12 carbon atoms. 8,
Which is a copolymer of the α-olefin of formula (I) and a specific chain non-conjugated diene represented by the above formula (I), wherein the chain non-conjugated diene (I) content is 0.05 to 50 mol%, preferably 0. .1
.About.30 mol%.

The unsaturated character of this unsaturated copolymer resin is α
-Pending from the copolymer chain via an alkylene group without affecting the copolymerization with olefins

[0013]

[Chemical 3]

It is understood that it depends on the base. This unsaturated copolymer resin is crystalline. The crystallinity is such that the crystallinity by X-ray analysis is 10% or more, preferably 20 to 70%.
Is indicated by. The unsaturated copolymer further contains a small amount of copolymer such as acrylic acid, methacrylic acid alkyl ester, vinyl acetate, etc. up to about 15 mol% based on the total amount of both monomers. Good.

The unsaturated copolymer should have a molecular weight and / or melting point sufficient to call it a resin. The molecular weight is typically 3,000 or more in terms of number average molecular weight, or the melting point is typically 40 ° C. or more.

<Α-Olefin> Examples of the above α-olefin which is one of the constituents of the unsaturated copolymer resin include ethylene, propylene, 1-butene, 1-hexene and 3-methyl-1-butene. , 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1
-Butene, 4,4-dimethyl-1-pentene, 3-methyl-1-hexene, 4-methyl-1-hexene, 4,4
-Dimethyl-1-hexene, 5-methyl-1-hexene, allylcyclopentane, allylcyclohexane, allylbenzene, 3-cyclohexyl-1-butene, vinylcyclopropane, vinylcyclohexane, 2-vinylbicyclo [2,2,1] ] -Heptane etc. can be mentioned. Of these, preferred examples are ethylene,
Propylene, 1-butene, 1-hexene, 3-methyl-
1-butene, 3-methyl-1-pentene, 4-methyl-
1-Pentene, 3-methyl-1-hexene and the like can be mentioned, and ethylene, propylene, 1-butene, 3-methyl-1-butene and 4-methyl-1-pentene are particularly preferable. These α-olefins may be used alone or in combination of two or more. In particular,
When the α-olefin is 1-hexene, ethylene, propylene, 1-butene, 4-methyl-1-pentene, 3
It is preferably used in combination with at least one of -methyl-1-butene. When using two or more α-olefins,
The α-olefin may be randomly distributed in the unsaturated copolymer resin, or may be distributed in blocks.

<Chain Non-Conjugated Diene> The chain non-conjugated diene to be copolymerized with the above α-olefin is represented by the following formula (I).

[0018]

[Chemical 4]

(Where n is an integer of 1 to 10 and R is
¹~ R³Is H or an alkyl group having 8 or less carbon atoms
The chain non-conjugated diene represented by the formula (I) is
Considering the introduction efficiency of the rufonic acid group and the economy of unsaturated copolymerization
Then, preferably n is 1 to 5 and R¹, R²And R
³Are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
And R¹, R²And R³Are all hydrogen atoms
Something. Furthermore, it is particularly preferable that n is 1 to
3 in R¹Is an alkyl group having 1 to 3 carbon atoms, R²And R
³Is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms
And R²And R³Are not simultaneously hydrogen atoms,
It Even more preferably, n is 3 and R¹Is methyl
Group, R²And R³Is a hydrogen atom or a methyl group
And R²And R³Are not hydrogen atoms at the same time
It

As specific examples of such chain-like non-conjugated dienes, for example, the following ones are suitable. (A) Chain-shaped 1,4-dienes such as 2-methyl-1,
4-pentadiene, 4-methylidene-1-hexene,
1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,4-heptadiene, 4-ethyl-1,4-hexadiene, 4,
5-dimethyl-1,4-hexadiene, 4-methyl-
1,4-heptadiene, 4-methyl-1,4-heptadiene, 5-methyl-1,4-heptadine, 5-methyl-
(B) Chain-shaped 1,5-dienes such as 1,4-octadiene, for example, 1,5-heptadiene, 1,5-octadiene, 5-methyl-1,5-heptadiene, 6-methyl-
(C) chain-like 1,6-dienes such as 1,5-heptadiene and 2-methyl-1,5-hexadiene, for example, 1,6
-Octadiene, 6-methyl-1,6-octadiene,
7-methyl-1,6-octadiene, 2-methyl-1,
6-heptadiene, 6-methylidene-1-octene, 6
-Ethyl-1,6-octadiene, 6,7-dimethyl-
1,6-octadiene, 1,6-nonadiene, 6-ethyl-1,6-nonadiene, 7-methyl-1,6-nonadiene, 7-methyl-1,6-decadiene, etc. 7-dienes such as 1,7-nonadiene, 7-
Methyl-1,7-nonadiene, 8-methyl-1,7-nonadiene, 2-methyl-1,7-octadiene, etc.,
(E) Chain-shaped 1,8-dienes such as 8-methyl-1,
8-decadiene, 9-methyl-1,8-decadiene and the like.

Among these examples, a particularly preferable example is 4
-Methyl-1,4-hexadiene, 5-methyl-1,4
-Hexadiene, 6-methyl-1,6-octadiene and 7-methyl-1,6-octadiene, most preferably 7-methyl-1,6-octadiene and 6-
Methyl-1,6-octadiene. These non-conjugated dienes may be used alone or in combination of two or more, and the preferable example of the latter is a combination of 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene (weight ratio 9
5: 5 to 5:95).

The unsaturated copolymer resin to be modified according to the present invention is obtained by converting these α-olefins and chain non-conjugated dienes into α-olefin polymer by using a Ziegler-Natta catalyst for α-olefin polymerization. It can be produced by copolymerization using a method and an apparatus similar to the production. Specific examples of such a production method include JP-A Nos. 55-165907, 56-30414, and 56
Examples thereof include those described in JP-A-36508, 57-155206, and JP-A-2-145611.

These chain non-conjugated dienes may be randomly distributed in the unsaturated copolymer resin, or may be distributed in blocks. The preferred content of the chain non-conjugated diene in the unsaturated copolymer resin is 0.1 to 30.
Mol%, particularly preferably 0.5 to 15 mol%.
If it is less than 0.05 mol%, there is a drawback that it is difficult to increase the efficiency of introducing a sulfonic acid group because the unsaturated copolymer resin has a small amount of unsaturated groups. On the other hand, if it exceeds 50 mol%,
When producing the unsaturated copolymer resin, the copolymerization rate is slow,
In the case of slurry polymerization, the amount of solvent-soluble by-product polymer increases, the viscosity of the polymerization system increases, and the productivity is poor, and the resulting unsaturated copolymer becomes sticky or does not maintain the resin state. There are drawbacks such as.

The molecular weight of the unsaturated copolymer resin is not particularly limited as long as it maintains the above-mentioned resin state, but for example, α
-If the olefin consists mainly of propylene, J
The melt flow rate (MFR) measured according to IS-K-6758 is usually 0.001 to 1000 g / 10.
Minutes, preferably 0.01 to 500 g / 10 minutes, particularly preferably 0.05 to 100 g / 10 minutes. Further, this unsaturated copolymer resin is JIS-K
-7203 has an elastic modulus of 1,000 to 80,000k
g / cm ² , preferably 2,000 to 80,000 kg
/ Cm ² , within the range.

Examples of preferable types of unsaturated copolymer resins from the viewpoint of the molecular structure are as follows. (1) A random copolymer of one or more α-olefins and one or more chain non-conjugated dienes, (2) one or more α-olefin polymer blocks, and one or two A block copolymer consisting of one or more α-olefins and a random copolymerization block of one or two or more chain non-conjugated dienes (the type and amount ratio of α-olefins in the α-olefin polymerization block are random copolymers). (The same as or different from those of the α-olefin of the polymer block), (3) Random copolymerization of one or more α-olefins with one or more chain non-conjugated dienes Block (block a)
And a random copolymer block (block b) of α-olefin and a chain non-conjugated diene, the block b
A block copolymer in which at least one of the type, number, and amount ratio of α-olefins, and the type, number, and amount ratio of chain-like non-conjugated dienes contained in (1) is a block different from block a.

Here, the "block copolymer" means the following copolymer. For example, "a block copolymer comprising a homopolymerization block of monomer A and a random copolymerization block of monomer A and monomer B" means a homopolymerization block of monomer A and a random copolymerization of monomer A and monomer B. In addition to those in which the block is chemically bound to form a composition such as A ... A-AABABAAAAB ..., the homopolymerized block of the monomer A and the monomer A are also included. Containing a copolymer in which a random copolymerization block of the monomer B and the monomer B is chemically bonded, and also containing a homopolymer of the monomer A or a random copolymer of the monomer A and the monomer B as a mixture. Also means.

Similarly, "a block copolymer comprising a polymerized block a and a polymerized block b" means that a composition in which the polymerized block a and the polymerized block b are chemically bonded constitutes the entire composition. In addition to the above, a mixture containing a copolymer in which the polymerized block a and the polymerized block b are chemically bonded, and a polymer composed only of the polymerized block a, a polymer composed only of the polymerized block b, and the like are also contained as a mixture. But
Is also meant and has the same meaning as a so-called "block copolymer" synthesized using a Ziegler-Natta catalyst.

Specific preferred examples of these unsaturated copolymer resins include (A-i) a random copolymer of propylene and 4-methyl-1,4-hexadiene, (A-
ii) Random copolymer of propylene and 5-methyl-1,4-hexadiene, (A-iii) Random copolymer of propylene and 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene Polymer, (A-iv) propylene, ethylene, 4-methyl-1,4-hexadiene and 5
-Random copolymer with methyl-1,4-hexadiene, (Av) propylene homopolymer block, and propylene with 4-methyl-1,4-hexadiene and 5-
Random copolymer block with methyl-1,4-hexadiene, block copolymer consisting of (A-vi) homopolymer block of propylene, and ethylene and 4-methyl-
Random copolymer block of 1,4-hexadiene and 5-methyl-1,4-hexadiene, block copolymer consisting of (A-vii) ethylene homopolymer block, and propylene and 4-methyl-1,4 -A block copolymer consisting of a random copolymer block of hexadiene and 5-methyl-1,4-hexadiene, (A-viii) Random copolymer block of propylene and ethylene, and propylene, ethylene and 4-methyl- A block copolymer composed of a random copolymer block of 1,4-hexadiene and 5-methyl-1,4-hexadiene, (A-
ix) ethylene and 4-methyl-1,4-hexadiene and 5
Block copolymer consisting of a random copolymer block with methyl-1,4-hexadiene and a random copolymer block with propylene and 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene , (A
-X) Random copolymerization block of propylene and 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene, and propylene, ethylene and 4-methyl-1,4-hexadiene and 5-methyl- Random copolymerization block with 1,4-hexadiene, block copolymer consisting of (A-xi) propylene and 4-methyl-1,4
-Random copolymer block of hexadiene and 5-methyl-1,4-hexadiene, propylene, ethylene and 4
-Methyl-1,4-hexadiene and 5-methyl-1,4
A random copolymer block with hexadiene and a random copolymer block with ethylene and 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene, (A-xii) Ethylene and 4-methyl-1,4-hexadiene and 5-methyl-
A block copolymer comprising a random copolymer block with 1,4-hexadiene, and a random copolymer block with propylene, ethylene, 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene, (A
-Xiii) random copolymer of ethylene and 1,4-hexadiene, (A-xiv) ethylene and 4-methyl-1,4
-Random copolymer with hexadiene, random copolymer with (A-xv) ethylene and 5-methyl-1,4-hexadiene, (A-xvi) ethylene with 4-methyl-1,4
-Random copolymer of hexadiene and 5-methyl-1,4-hexadiene, (A-xvii) ethylene, propylene, 4-methyl-1,4-hexadiene and 5-methyl-
Random copolymer with 1,4-hexadiene, (A-xv
iii) Random copolymer of ethylene, butene, 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene, (A-xix) ethylene, 1-hexene and 4
-Methyl-1,4-hexadiene and 5-methyl-1,4
-Random copolymer with hexadiene, (A-xx) ethylene and 4-methyl-1-pentene and 4-methyl-1,4
-A block copolymer comprising a random copolymer of hexadiene and 5-methyl-1,4-hexadiene, a homopolymer block of (A-xxi) ethylene, and a random copolymer block of ethylene and 1,4-hexadiene. Union, (A
-Xxii) ethylene homopolymer block and ethylene and 4
-Methyl-1,4-hexadiene and 5-methyl-1,4
A random copolymer of hexadiene, a block copolymer consisting of (A-xxiii) 1-butene, 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene , A random copolymer of (A-xxiv) 3-methyl-1-butene, 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene, (A-xxv) 4-methyl-1 -Random copolymer of pentene and 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene, random copolymerization of (Bi) propylene and 7-methyl-1,6-octadiene A random copolymer of (B-ii) propylene, ethylene and 7-methyl-1,6-octadiene, (B-ii)
iii) a block copolymer comprising a homopolymerization block of propylene and a random copolymerization block of propylene and 7-methyl-1,6-octadiene, (B-iv)
Homopolymer block of propylene, and ethylene and 7-
Random copolymerization block with methyl-1,6-octadiene, block copolymer consisting of (Bv) ethylene homopolymerization block, and propylene and 7-methyl-
Random copolymerization block with 1,6-octadiene, block copolymer consisting of (B-vi) random copolymerization block with propylene and ethylene, and with propylene, ethylene and 7-methyl-1,6-octadiene Random copolymer block, block copolymer consisting of (B
-Vii) random copolymer block of ethylene and 7-methyl-1,6-octadiene, and propylene and 7-
Random copolymerization block with methyl-1,6-octadiene, (B-viii) Random copolymerization block with propylene and 7-methyl-1,6-octadiene, and propylene, ethylene and 7 Block copolymer consisting of a random copolymer block with -methyl-1,6-octadiene, a random copolymer block with (B-ix) ethylene and 7-methyl-1,6-octadiene, and propylene and ethylene 7-methyl-
A block copolymer consisting of a random copolymer block with 1,6-octadiene, (Bx) 3-methyl-1-
Random copolymer of butene and 7-methyl-1,6-octadiene, (Ci) propylene and 4-methyl-1,
Random copolymer of 4-hexadiene and 5-methyl-1,4-hexadiene and 7-methyl-1,6-octadiene, (C-ii) ethylene, propylene and 4-methyl-
A random copolymer of 1,4-hexadiene and 5-methyl-1,4-hexadiene and 7-methyl-1,6-octadiene, (C-iii) propylene homopolymer block,
And propylene and 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene and 7-methyl-
Examples thereof include a block copolymer composed of a random copolymer block with 1,6-octadiene, and the like.

Of these, a particularly preferable example is α
From the standpoints of availability of olefins and ease of production of copolymers, (a) a random copolymer of propylene, 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene, ( B) Homopolymer block of propylene, and ethylene and 4-methyl-1,4-hexadiene and 5
Block copolymer consisting of a random copolymer block with -methyl-1,4-hexadiene, (c) ethylene and 4-methyl-1,4-hexadiene and 5-methyl-1,
Random copolymer with 4-hexadiene, (d) random copolymer consisting of propylene, ethylene, 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene, (e) ethylene and 4- Random copolymer block of methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene, and propylene and 4-methyl-
Random copolymer block composed of 1,4-hexadiene and 5-methyl-1,4-hexadiene block copolymer, (f) Random copolymer of propylene and 7-methyl-1,6-octadiene , (To) propylene homopolymer block, and ethylene, propylene and 7-
Block copolymer consisting of random copolymer block with methyl-1,6-octadiene, homopolymer block of (h) propylene, and propylene and 7-methyl-
Random polymerization block of 1,6-octadiene, block copolymer consisting of, (ri) random copolymer of ethylene and propylene and 7-methyl-1,6-octadiene, (nu) random of ethylene and propylene Block copolymer comprising a copolymer block and a random copolymer block of propylene and 7-methyl-1,6-octadiene, (l) a random copolymer block of ethylene and propylene, and ethylene, propylene and 7- A block copolymer consisting of a random copolymer block with methyl-1,6-octadiene, (wo) 3-methyl-1
Examples thereof include a random copolymer of -butene and 7-methyl-1,6-octadiene.

(Unsaturated Copolymer Resin Nonwoven Fabric) Manufacturing Method of Nonwoven Fabric A method of forming a nonwoven fabric using the unsaturated copolymer resin is as follows:
All the production methods generally known as the dry method are possible.
For example, once formed into a fibrous multifilament, it is cut into short fibers, the fibers are aligned with a card machine, and then woven with a needle punch or a heat roll to obtain a nonwoven fabric, which is known as a spunlace method. A method of forming a non-woven fabric by entanglement with a high-pressure water stream is mentioned. Furthermore, a method called a spun bond method or a melt blow method, in which a fiber is formed from a molten resin and a non-woven fabric is directly finished, can be mentioned.

The unsaturated copolymer resin may be sulfonated by the method described below and then formed into a nonwoven fabric. The basis weight of the nonwoven fabric is 20 to 80 g / m ² , and the wall thickness is 0.
05-2 mm is preferable. The porosity of this nonwoven fabric is preferably 30 to 90% as calculated by the following formula.

[0032]

[Equation 1]

[Wherein w is the weight of the nonwoven fabric per unit area (g / m ² ), t is the thickness of the nonwoven fabric (cm), and ρ is the density of the unsaturated copolymer resin (g / cm ³ ). Is. ]

Sulfonation method In the method of introducing a sulfonic acid group into the olefinic unsaturated bond of the unsaturated copolymer resin of the nonwoven fabric, it is difficult to control the reaction and halogen is introduced at the same time as the sulfonic acid group. There is no particular limitation except for the method using sulfonic acid. For example, (a) a method using concentrated sulfuric acid, fuming sulfuric acid, sulfuric anhydride or sulfur trioxide, (b) a sulfur trioxide donor such as the above-mentioned sulfuric acid or sulfur trioxide, and acetic anhydride, acetic acid, dioxane, tetrahydrofuran, pyridine. , Dimethylaniline, dimethylformamide, N-methylpyrrolidone, triethyl phosphate, triethylamine, and the like, and a method of using a complex with a Lewis base, and (c) an acidic sulfite or metasulfite of an alkali metal salt such as sodium sulfite is used. I can give you a way.

The reaction is carried out in a state where the unsaturated copolymer of the nonwoven fabric is swollen or dissolved in a solvent. The solvent to be used should be appropriately selected depending on the type of reaction, but among fatty acids, alicyclic and aromatic hydrocarbons and their halides, esters having 6 or more carbon atoms, ketones, aethers and carbon disulfide. Often selected from Of course, these solvents can be used as a mixed solvent of two or more kinds.

The amount of sulfonic acid groups introduced was determined by using an electronic spectrochemical analyzer of "ESCA1000" (trade name) manufactured by Shimadzu Corporation, using magnesium K-α rays as an X-ray source, and the elements on the surface of the non-woven fabric. Analysis is performed and the abundance ratio of sulfur (S) element and carbon (C) element is processed by the data system ESPA1000 for surface analysis, and the sensitivity coefficient at that time is 1.00 for C _{1s and 1} for S _2p. A value such that the abundance ratio (S / C) of sulfur element to carbon element when it is 0.74 is in the range of 0.02 to 0.07 is preferable.

[0037]

【Example】

(Example-1) Propylene (97.0 mol%), and 7
A random copolymer (MFR of 31 g / min) consisting of -methyl-1,6-octadiene (3.0 mol%) was melt extruded at 240 ° C using a spunbond nonwoven fabric manufacturing apparatus to give an average fiber diameter of 10 µm. A fibrous form was made to form the web. The obtained web was passed through a hot roll at 140 ° C. to heat-bond each fiber, and finally a nonwoven fabric having a thickness of 0.1 mm and a basis weight of 40 g / m ² was obtained. Width 20
cm, commercially available acetic anhydride (340 ml) and concentrated sulfuric acid (80 cc) were mixed little by little in a beaker having a volume of 1 liter while maintaining the temperature at 10 ° C, and the temperature was raised to 60 ° C after the mixing was completed. 1.0 cm of the above two non-woven fabrics with a width of 20 cm and a length of 50 cm
Soak for 1 hour, then wash with running water for 1 hour, and dry with hot air at 90 ° C to sulfonate the separator (porosity 56
%) Was obtained. The degree of sulfonation of the non-woven fabric, the absorption rate test of the electrolytic solution, and the cutting load of the non-woven fabric were measured.
The results are shown in Table 1.

(Example-2) As a sulfonation procedure,
400 ml of commercially available concentrated sulfuric acid 10 in a 1 liter beaker
While maintaining at 5 ° C., two non-woven fabrics having a width of 20 cm and a length of 50 cm are immersed for 0.5 hours, then washed under running water for 1 hour and dried with hot air at 90 ° C. in the same manner as in Example-1. The sulfonated nonwoven fabric separator (porosity 56
%) Was obtained. The evaluation of this nonwoven fabric was performed in the same manner as in Example-1. The results are shown in Table 1.

(Comparative Example-1) As a material for non-woven fabric, MF
A sulfonated nonwoven fabric was obtained by the same method as in Example 1 except that a propylene homopolymer in which R was 30 g / 10 min was used. The results are shown in Table 1.

(Comparative Example-2) As a material for non-woven fabric, MF
A sulfonated nonwoven fabric was obtained in the same manner as in Example-2 except that a propylene homopolymer having R of 30 g / 10 min was used. The results are shown in Table 1.

(Comparative Example-3) As a material for non-woven fabric, MF
A sulfonated nonwoven fabric was obtained by the same method as in Example 1 except that a random copolymer of propylene (91.8 mol%) and ethylene (8.2 mol%) in which R was 26 g / 10 min was used. The results are shown in Table 1.

(Comparative Example-4) As a material for a non-woven fabric, MF
A sulfonated nonwoven fabric was obtained in the same manner as in Example-2 except that a random copolymer of propylene (91.8 mol%) and ethylene (8.2 mol%) with R of 26 g / 10 min was used. The results are shown in Table 1. In addition, in the Examples and Comparative Examples, the measuring method of the sulfonation degree, the electrolytic solution absorption rate test method, and the cutting load measuring method used are as follows.

Electrolyte Absorption Rate Test 5 pieces of 2.5 cm × 20 cm test piece were prepared, and the bottom end of the test piece was immersed in a 30% by weight aqueous solution of potassium caustic at 20 ± 2 ° C. for 30 seconds by capillary action. The average height of rise of the potash solution was measured at the time point.

Cleavage load of non-woven fabric Five test pieces each having a width of 30 mm and a length of 300 mm are prepared, pulled in the longitudinal direction, and the average load until cutting is measured.

[0045]

[Table 1]

[0046]

[Effect] The battery separator of the present invention is excellent in electrolyte solution absorption rate and strength.

Claims (1)

[Claims] 1. An α-olefin having 2 to 12 carbon atoms and at least one chain non-conjugated diene represented by the following formula (I), wherein the chain non-conjugated diene content is 0. Unsaturated copolymer resin of 0.05 to 50 mol% (Wherein n represents an integer of 1 to 10 and R ^{1 to} R ³ each represent H or an alkyl group having 8 or less carbon atoms) as a base material Battery separator.