JPH0841260A - Electret - Google Patents

Abstract

PURPOSE:To obtain the electret, containing a cyclic olefinic resin and a specific modified polymeric compound, having a high charge density even at normal to high temperatures, excellent in retention of the surface charge density thereof and useful for automotive parts, etc. CONSTITUTION:This electret comprises a composition containing (A) a cyclic olefinic resin and (B) a modified polymeric compound prepared by carrying out the graft copolymerization of (ii) at least one modifying monomer selected from an unsaturated carboxylic acid and its derivative with (i) a polymeric compound. Furthermore, the amount of the grafted component (ii) in the component (B) is preferably 0.05-15wt.% and the content of the component (B) based on 100 pts.wt. component (A) is preferably 2-15 pts.wt. The component (B) is preferably a modified alpha-olefin (co)polymer or a modified cyclic olefinic resin. For example, a cyclic olefinic resin represented by the formula [(k) and (h) are each 0 or 1; (1) is 0 or a positive integer; R<1> to R<18>, R<a> and R<b> are each H, a halogen or a hydrocarbon] is preferably used as the component (A).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electret,
In particular, the present invention relates to an electret having various properties such as a high surface charge density and excellent retention of the surface charge density at high temperatures.

[0002]

2. Description of the Related Art Electrets have been widely used in various applications such as materials for audio equipment such as microphones, pickups and speakers; electronic copying and printing applications; medical materials. Further, the electret is used in various forms such as a film, a sheet, a fiber, a non-woven fabric, etc., depending on its usage. In particular, an electret filter obtained by molding an electret is widely used for applications such as an air filter.

When this electret filter is used for an air filter of an automobile or the like, it is required to have charge retention at high temperature.

Conventionally, as this electret, a nonpolar polymer compound such as polypropylene, a polar polymer compound such as polycarbonate, and a modified nonpolar polymer compound graft-modified with a polar group-containing compound such as maleic anhydride are blended. A resin composition comprising the following is proposed (Japanese Patent Publication No. 59-23098 and Japanese Patent Laid-Open No. 60).
-225416 publication).

[0005]

However, the electret made of the above-mentioned conventional resin composition has room for improvement in the surface charge retention property at room temperature to high temperature.

Therefore, an object of the present invention is to provide an electret which has a high charge density even at room temperature or high temperature and which is excellent in retaining the surface charge density.

[0007]

In order to solve the above problems, the present invention provides a cyclic olefin resin (A) and a polymer compound containing at least one modified monocarboxylic acid and a derivative thereof. The present invention provides an electret composed of a resin composition containing a modified polymer compound (B) obtained by graft-copolymerizing a monomer.

The electret of the present invention will be described in detail below.

The cyclic olefin resin which is a constituent of the resin composition used as the raw material of the electret of the present invention is represented by the following formulas (I) and (II)

[0010]

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The cyclic olefin (a) and /
Alternatively, the main component is (b). The cyclic olefin-based resin (A) used in the present invention may be composed of one kind of the cyclic olefins (a) and (b), or may be a combination of two or more kinds.

The above formula (I) representing the cyclic olefin (a)
In, k is 0 or 1, l is 0 or a positive integer, h is 0 or 1, R ^{1 to} R ¹⁸ , and Ra and Rb may be the same or different, and a hydrogen atom. A halogen atom or a hydrocarbon group, R ¹⁵ ,
R ¹⁶ , R ¹⁷ and R ¹⁸ may be bonded to each other to form a cyclic group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
The hydrocarbon group has, for example, 1 to 2 carbon atoms.
Examples thereof include an alkyl group of 0 and a cycloalkyl group having 3 to 15 carbon atoms. Specific examples of the alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, amyl group, hexyl group, octyl group, decyl group, dodecyl group and octadecyl group.
Specific examples of the cycloalkyl group having 3 to 15 carbon atoms include a cyclohexyl group and the like.

In addition, R^Fifteen, R¹⁶, R¹⁷And R¹⁸Is mutual
To form a cyclic group, for example, R
^FifteenAnd R¹⁶, R¹⁷And R¹⁸, R^FifteenAnd R¹⁷, R¹⁶And R¹⁸, R^Fifteen
And R ¹⁸, Or R¹⁶And R¹⁷And are connected to each other
To form (in cooperation with each other) a monocyclic or polycyclic group.
May be made. Also, the monocyclic or polycyclic ring formed
The group having a group may have a double bond.

Specific examples of the monocyclic or polycyclic group formed by combining R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ with each other include the following formulas:

[0016]

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A group represented by: In this monocyclic or polycyclic group, the carbon atom marked 1 and 2 of the numbers, in formula (I), the alicyclic hydrocarbon structure group represented by R ¹⁵ to R ¹⁸ are bonded Represents a carbon atom.

R ¹⁵ and R ¹⁶ , and R ¹⁷ and R ¹⁸ are
They may be bonded to each other to form an alkylidene group. Examples of the alkylidene group include an alkylidene group having 2 to 20 carbon atoms such as an ethylidene group, a propylidene group and an isopropylidene group.

In the above formula (II) representing the cyclic olefin (b), p is 0 or a positive integer, preferably 0 to 3. Further, m and n are 0, 1 or 2. Further, q is 0 or a positive integer, preferably 0 or 1.

R ^{19 to} R ³⁷ may be the same or different and each is a hydrogen atom, a halogen atom or a hydrocarbon group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Moreover, as a hydrocarbon group, a C1-C10 alkyl group, a C5-C15 cycloalkyl group, a C6-C12 aromatic hydrocarbon group etc. can be mentioned. Specific examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, isopropyl group, isobutyl group, n-amyl group, neopentyl group, n-hexyl group,
Examples thereof include n-octyl group, n-decyl group and 2-ethylhexyl group, and specific examples of the cycloalkyl group having 5 to 15 carbon atoms include cyclohexyl group, methylcyclohexyl group, ethylcyclohexyl group and the like. be able to. Further, specific examples of the aromatic hydrocarbon group having 6 to 12 carbon atoms include a phenyl group, a naphthyl group and a biphenyl group.

Further, the carbon atom to which R ²⁷ is bonded and R ³¹
The carbon atom to which R is bonded, or the carbon atom to which R ²⁸ is bonded and the carbon atom to which R ²⁹ is bonded may be bonded via an alkylene group having 1 to 3 carbon atoms. ,
Further, they may be directly bonded without any group.

Further, when n = m = 0, R ³³ and R ³⁰ ,
Alternatively, R ³³ and R ³⁷ may be bonded to each other to form a monocyclic or polycyclic aromatic ring. In particular, n = m =
When it is 0, it is preferable that R ³³ and R ³⁰ are bonded to each other to form a group represented by the following formula. In the formula below,
q is the same as in formula (II).

[0023]

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Represented by the above formula (I) or (II)
Specific examples of the cyclic olefin (a) or (b) include:
Bicyclo [2.2.1] hept-2-ene derivative, tri
Cyclo [4.3.0.1^2,5] -3-decene derivative,
Ricyclo [4.3.0.1^{2, Five}] -3-Undecene induction
Body, tetracyclo [4.4.0.1^2,5． 1^7,10] -3
-Dodecene derivative, pentacyclo [6.6.1.
1^3,6． 0^2,7． 0^9,14] -4-Hexadecene derivative,
Pentacyclo [6.5.1.1^3,6． 0^2,7． 0^9,13]
-4-Hexadecene derivative, pentacyclo [7.4.
0.1^2,5． 1^9,12． 0 ^8,13] -3-Pentadecene derivative
Body, pentacyclopentadecadiene derivative, pentacic
B [8.4.0.1^2,5． 1^9,12． 0^8,13] -3-Pen
Hexacyclo [6.6.1.1], a tadecene derivative^3,6．
1^10,13． 0^2,7． 0^9,14] -4-Heptadecene induction
Body, heptacyclo [8.7.0]^13.6． 1^10,17． 1
^12,15． 0^2,7． 0^11,16] -4-Eicosene derivative,
Heptacyclo [8.7.0.1^3,6． 1^{Ten , 17}． 1
^12,17． 0^2,7． 0^11,16] -5-Eicosene derivative,
Heptacyclo [8.8.0.1^4,7． 1^11,18． 1
^13,16． 0^3,8． 0^12,17] -5-Hen Eicosene Induction
Body, heptacyclo [8.8.0]^12,9． 1^4,7．
1^11,18． 0^3,8． 0 ^12,17] -5-Hen Eikosen invitation
Conductor, octacyclo [8.8.0.1^2,9． 1 ^4,7． 1
^11,18． 1^13,16． 0^3,8． 0^12,17] -5-docosene
Derivative, nonacyclo [10.9.1.1^4,7．
1^13,20． 1^15,18． 0^3,8． 0^2,10． 0^12,21． 0
^14,19] -5-Pentacocene derivative, nonacyclo [1
0.10.1.1^5,8． 1^14,21． 1^16,19． 0^2,11．
0^4,9． 0^13,22． 0^15,20] -5-hexacocene derivative
Body 1,4-methano-1,4,4a, 9a-tetrahydro
Fluorene derivative, 1,4-methano-1,4,4a,
5,10,10a-hexahydroanthracene derivative,
Cyclopentadiene-acenaphthylene adduct derivatives
And so on.

Further, specific compounds of the cyclic olefin represented by the above formula (I) or (II) include the compounds shown below.

[0026]

[Chemical 4]

[0027]

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[0028]

[Chemical 6]

[0029]

[Chemical 7]

[0030]

Embedded image

[0031]

[Chemical 9]

[0032]

[Chemical 10]

[0033]

[Chemical 11]

[0034]

[Chemical 12]

[0035]

[Chemical 13]

[0036]

Embedded image

[0037]

[Chemical 15]

[0038]

Embedded image

[0039]

[Chemical 17]

[0040]

Embedded image

[0041]

[Chemical 19]

[0042]

Embedded image

[0043]

[Chemical 21]

[0044]

[Chemical formula 22]

[0045]

[Chemical formula 23]

[0046]

[Chemical formula 24]

[0047]

[Chemical 25]

[0048]

[Chemical formula 26]

As the cyclic olefin (a) or (b) represented by the formula (I) or (II), 1,4,5,8-dimethano-1,2,3, in addition to the above compounds, can be used. ，
4,4a, 5,8,8a-octahydronaphthalene, 2
-Methyl-1,4,5,8-dimethano-1,2,3,
4,4a, 5,8,8a-octahydronaphthalene, 2
-Ethyl-1,4,5,8-dimethano-1,2,3,
4,4a, 5,8,8a-octahydronaphthalene, 2
-Propyl-1,4,5,8-dimethano-1,2,3
4,4a, 5,8,8a-octahydronaphthalene, 2
-Hexyl-1,4,5,8-dimethano-1,2,3,3
4,4a, 5,8,8a-octahydronaphthalene,
2,3-dimethyl-1,4,5,8-dimethano-1,
2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-methyl-3-ethyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8, 8a-octahydronaphthalene, 2-chloro-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-bromo-1,4,5,5 8-Dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-fluoro-1,4,5,8-dimethano-1,2,3,4,4a, 5 8,8a-octahydronaphthalene, 2,3-dichloro-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-cyclohexyl-1, 4, 5, 8
-Dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-n-butyl-1,4,5,5
8-Dimethano-1,2,3,4,4a, 5,8,8a-
Octahydronaphthalene, 2-isobutyl-1,4
5,8-Dimethano-1,2,3,4,4a, 5,8,8
Examples thereof include octahydronaphthalene such as a-octahydronaphthalene.

The cyclic olefin (a) or (b) represented by the formula (I) or the formula (II) is obtained by condensing cyclopentadiene and the corresponding olefin or cyclic olefin by the Diels-Alder reaction. Can be easily manufactured.

In the present invention, the cyclic olefin resin (A) contains a cyclic olefin (a) represented by the above formula (I) and / or a cyclic olefin (b) represented by the above formula (II) as a main component. Random copolymerization obtained by addition polymerization of the cyclic olefin (a) represented by the formula (I) and / or the cyclic olefin (b) represented by the formula (II) and ethylene. Compound (cyclic olefin random copolymer), a single ring-opening polymer of the cyclic olefin (a) represented by the formula (I) or a single ring-opening of the cyclic olefin (b) represented by the formula (II). Polymer, ring-opening copolymer of cyclic olefin (a) represented by formula (I) and cyclic olefin (b) represented by formula (II) (cyclic olefin ring-opening (co) polymer), or these Is a hydrogenated product.

In addition to ethylene, the cyclic olefin resin (A) may contain other olefin compound as a copolymerized unit within a range not impairing the characteristics of the electret of the present invention. Other olefin compounds include, for example, propylene, 1-butene, 4-methyl-
1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, etc. α-olefins having 3 to 20 carbon atoms; cyclopentene, Cyclohexene, 3-methylcyclohexene, cyclooctene,
3a, 5,6,7a-tetrahydro-4,7-methano-
Alicyclic hydrocarbons such as 1H-indene; 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,7-octadiene, dicyclopentadiene, 5-ethylidene 2-norbornene, 5-vinyl-2-norbornene and other non-conjugated dienes; norbornene-2, 5-methylnorbornene-2,
5-Ethylnorbornene-2,5-isopropylnorbornene-2,5-n-butylnorbornene-2,5-i
-Butylnorbornene-2,5,6-dimethylnorbornene-2,5-chloronorbornene-2,2-fluoronorbornene-2,5,6-dichloronorbornene-2
And the like norbornenes. These other olefin compounds may be contained alone or in combination of two or more in the cyclic olefin resin (A). Among these, α-olefins having 3 to 15 carbon atoms are preferable, and α-olefins having 3 to 10 carbon atoms are particularly preferable.

When a compound having two or more double bonds in the molecule is used as a cyclic olefin other than the cyclic olefins represented by the formulas (I) and (II), hydrogenation is carried out for the purpose of improving heat resistance and the like. Can be used.

The cyclic olefin random copolymer, which is a specific example of the cyclic olefin resin (A), is usually represented by the cyclic olefin (a) represented by the formula (I) and / or the formula (II). A cyclic olefin (b),
It is possible to produce ethylene, and optionally other olefin compounds, by reacting in a reaction solvent with a catalyst consisting of a vanadium compound soluble in the reaction solvent and an organoaluminum compound. it can.

In the obtained cyclic olefin random copolymer, the cyclic olefin (a) or (b) represented by the formula (I) or the formula (II) has the following formula (I-1) or (II-), respectively. It is considered that the repeating structural unit represented by 1) is formed.

[0056]

[Chemical 27]

In the above formula (I-1), k, l, h,
R ^{1 to} R ¹⁸ , Ra and Rb are as defined for the above formula (I). Further, in the above formula (II-1), p, q, m, n, and R ^{19 to} R ³⁷ are as defined for the above formula (II).

A ring-opening polymer of the cyclic olefin (a) represented by the formula (I) or a ring-opening polymer of the cyclic olefin (b) represented by the formula (II), or a ring-opening polymer of the formula (I). ) The cyclic olefin (a) represented by the formula (II) and the cyclic olefin (b) represented by the formula (II) (hereinafter, referred to as a ring-opening copolymer).
The "cyclic olefin ring-opening (co) polymer" means a cyclic olefin (a) represented by the above formula (I) and / or a cyclic olefin (b) represented by the above formula (II), and optionally The other olefin compound used according to the present invention comprises ruthenium, rhodium, palladium, osmium, indium, a halide of a metal such as platinum, a nitrate of these metals, or an acetylacetone compound of these metals, and a reducing agent. A catalyst; a halide of a metal such as titanium, palladium, zirconium, molybdenum, or an acetylacetone compound of these metals;
In the presence of a catalyst composed of organoaluminum (co)
It can be produced by polymerizing.

In the cyclic olefin ring-opening (co) polymer, the cyclic olefin (a) represented by the formula (I) and the cyclic olefin (b) represented by the formula (II) are respectively represented by the following formula (I- It is considered that the repeating structural unit represented by 2) or (II-2) is formed.

[0060]

[Chemical 28]

In the above formula (I-2), k, l, h,
R ^{1 to} R ¹⁸ , Ra and Rb are as defined for the above formula (I). Further, in the formula (II-2),
p, q, m, n, R ^{19 to} R ³⁷ are as defined for formula (II) above.

The hydrogenated product of the cyclic olefin ring-opening (co) polymer is obtained by reducing the cyclic olefin ring-opening (co) polymer obtained as described above with hydrogen in the presence of a hydrogenation catalyst. It can be manufactured.

In the hydrogenated product of the cyclic olefin ring-opening (co) polymer, the cyclic olefin (a) represented by the formula (I) and the cyclic olefin (b) represented by the formula (II) are respectively Formula (I-3) or (II-3)
It is considered that the repeating structural unit represented by

[0064]

[Chemical 29]

In the above formula (I-3), k, l, h,
R ^{1 to} R ¹⁸ , Ra and Rb are as defined for the above formula (I). Further, in the formula (II-3),
p, q, m, n, R ^{19 to} R ³⁷ are as defined for formula (II) above.

The cyclic olefin resin (A) produced as described above is subjected to a deashing step, a filtration step, a
It is purified through a precipitation process and the like. For example, the deashing process is
In this step, the catalyst residue remaining in the resin is removed by bringing the reaction mixture into contact with an alkaline aqueous solution. Also,
The precipitation step is a step of introducing the reaction mixture into a poor solvent for the resin to precipitate the resin dissolved in the reaction solvent.

In addition to the above, the cyclic olefin resin (A) used in the present invention is various methods previously proposed by the present applicant (Japanese Patent Laid-Open No. 60-168708, 61-12).
No. 0816, No. 61-115912, No. 61
-115916, 61-271308,
It can also be produced by appropriately selecting the conditions according to JP-A-61-272216, JP-A-62-252406 and JP-A-62-252407.

The cyclic olefin resin (A) has an iodine value of usually 5 (g / resin 100 g) or less, and most of them is 1 (g / resin 100 g) or less.

Further, a cyclic olefin random copolymer,
The cyclic olefin ring-opening (co) polymer and the hydrogenated product of the cyclic olefin ring-opening (co) polymer usually have an intrinsic viscosity [η] of 0.01 to 2 measured in decalin at 135 ° C.
0 dl / g, especially 0.05 to 10 dl /
g, more preferably 0.08 to 8 dl / g.

Further, the cyclic olefin resin (A) is
Generally, it is amorphous or low crystalline, preferably amorphous. Therefore, the cyclic olefin resin (A) has good transparency. The cyclic olefin resin (A) has a crystallinity of usually 5% or less, most of which is 0% as measured by X-ray diffraction, and a differential scanning calorimeter (DSC).
The melting point is not observed even if the melting point is measured with.

The cyclic olefin resin (A) has a high glass transition temperature (Tg) and softening temperature (TMA). Glass transition temperature (Tg) is usually 230 ° C
Hereinafter, preferably 50 to 230 ° C., particularly 100 to 200
Within the range of ° C. In particular, the cyclic olefin resin (A) having a softening temperature of 70 to 180 ° C. is preferable.

The thermal decomposition temperature of the cyclic olefin resin (A) is usually 350 to 420 ° C., especially 370 to
It is within the range of 400 ° C.

The mechanical properties of this cyclic olefin resin (A) are such that the tensile modulus is usually 1 × 10 4 to 5 × 10 5.
4 kg / cm ² , and the tensile strength is usually 300 to
It is 1500 kg / cm ² .

The density of the cyclic olefin resin (A) is usually in the range of 0.86 to 1.10 g / cm ³ , preferably 0.88 to 1.08 g / cm ³ .

The modified polymer compound (B), which is the component (B) of the resin composition constituting the electret of the present invention, comprises a polymer compound containing at least one modified monovalent monomer selected from unsaturated carboxylic acids and their derivatives. It is obtained by subjecting the body to graft copolymerization and modification.

The polymer compound as the main component of the modified polymer compound (B) may be an ordinary nonpolar polymer compound and is not particularly limited. As the polymer compound, for example, the above cyclic olefin resin (A), a homopolymer of α-olefin, a copolymer composed of two or more α-olefins,
Alternatively, a mixture of at least two selected from homopolymers and copolymers thereof can be used. α-
Examples of the olefin include ethylene, propylene,
1-butene, 1-pentene, 1-hexene, isopentene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-hexadecene,
1-octadezene, 1-eicosene and the like can be mentioned. Specific examples of the polymer compound include propylene, ethylene, polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene. -4-methyl-1-pentene copolymer, propylene / 1-butene copolymer, 4-methyl-1-pentene-1
A decene copolymer and the like.

Examples of the unsaturated carboxylic acid and its derivative which are modified monomers include acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid,
Itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, endocis-bicyclo [2,2,1] hept-5-ene-2,3-dicarboxylic acid (nadic acid), methyl-endocis-bicyclo [2,2] Unsaturated dicarboxylic acids such as 2,1] hept-5-ene-2,3-dicarboxylic acid (methyl nadic acid), and acid halides and amides of these unsaturated dicarboxylic acids as derivatives of these unsaturated dicarboxylic acids , Imide,
Examples thereof include acid anhydrides and esters. Specific examples of the derivative of the unsaturated dicarboxylic acid include maleenyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate and the like.
These unsaturated carboxylic acids and their derivatives may be used alone or in combination of two or more. Among these, unsaturated dicarboxylic acids and acid anhydrides thereof are preferable, and maleic acid, nadic acid and acid anhydrides thereof are particularly preferable.

The modified polymer compound (B) can be produced according to a conventional method without particular limitation. For example, according to a method such as a method of melting a polymer compound and adding a modifying monomer for graft copolymerization, or a method of dissolving the polymer compound in a solvent and adding a modifying monomer for copolymerization. It can be carried out. In either method, it is preferable to carry out the copolymerization reaction in the presence of a radical polymerization initiator, because the graft copolymerization can be carried out efficiently. Examples of the radical polymerization initiator used include organic peroxides, organic peresters, and azo compounds. In addition, radical generation may be promoted by irradiation with ionizing radiation, ultraviolet rays, or the like.

In the modified polymer compound (B), the content of at least one modified monomer selected from these unsaturated carboxylic acids and their derivatives, that is, the grafted amount of the modified polymer compound is usually 0. 0.05 to 15% by weight
And preferably 0.1 to 5% by weight.

The content ratio of the cyclic olefin resin (A) and the modified polymer compound (B) in the resin composition is
The ratio is 0.5 to 40 parts by weight, preferably 2 to 15 parts by weight, with respect to 100 parts by weight of the cyclic olefin resin (A).

Further, the resin composition forming the electret of the present invention may contain other resin in addition to the cyclic olefin resin (A) and the modified polymer compound (B). When the resin composition contains another resin, it is preferable that the other resin be finely dispersed in the cyclic olefin resin (A) to form a so-called polymer alloy.

Other resins used include the following (1)
To (17) are exemplified.

(1) Polymers Derived from Hydrocarbons Having One or Two Unsaturated Bonds Specific examples include polyethylene, polypropylene, polymethylbutene-1, poly-4-methylpentene-1, polybutene-1. And polyolefin such as polystyrene. These polyolefins may have a crosslinked structure.

(2) Halogen-containing vinyl polymer As specific examples, polyvinyl chloride, polyvinylidene chloride,
Examples thereof include polyvinyl fluoride, polychloroprene, polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, and chlorinated rubber.

(3) Polymers Derived from α, β-Unsaturated Acids and Derivatives Thereof As specific examples, polyacrylates, polymethacrylates, polyacrylamides, polyacrylonitriles, or copolymers of the above-mentioned monomers Polymer (eg;
Acrylonitrile / butadiene / styrene copolymer, acrylonitrile / styrene copolymer, acrylonitrile / styrene / acrylic acid ester copolymer) and the like can be mentioned.

(4) Polymers Derived from Unsaturated Alcohols, Amines, Acyl Derivatives or Acetals Specific examples thereof include polyvinyl alcohol, polyvinyl acetate, vinyl polythrea phosphate, vinyl polybenzoate, vinyl polymaleate, polyvinyl butyral, Examples thereof include polyallyl phthalate, polyallyl melamine, and copolymers (eg, ethylene, vinyl acetate copolymer) with the monomers constituting the polymer.

(5) Polymer Derived from Epoxide Specific examples include polymers derived from polyethylene oxide or bisglycidyl ether.

(6) Polyacetal Specific examples include polyoxymethylene, polyoxyethylene, and polyoxymethylene containing ethylene oxide as a comonomer.

(7) Polyphenylene oxide. (8) Polycarbonate. (9) Polysulfone.

(10) Polyurethane and urea resins. (11) diamine and dicarboxylic acid, aminocarboxylic acid,
Or polyamides and copolyamides derived from the corresponding lactams. Specific examples are nylon 6, nylon 66, nylon 1
1, nylon 12, etc. can be mentioned.

(12) Polyester Derived from Dicarboxylic Acid, Dialcohol, Oxycarboxylic Acid, or Corresponding Lactone Specific examples include polyester terephthalate, polybutylene terephthalate, and poly-1,4-dimethylol cyclohexane terephthalate. it can.

(13) Polymer Having Crosslinking Structure Derived from Aldehyde and Phenol, Urea or Melamine As specific examples, phenol / formaldehyde resin, urea / formaldehyde resin, melamine / formaldehyde resin and the like can be mentioned.

(14) Alkyd Resin Specific examples include glycerin / phthalic acid resins. (15) Derived from a copolyester which is a copolymer of a saturated or unsaturated dicarboxylic acid and a polyhydric alcohol,
An unsaturated polyester resin obtained by using a vinyl compound as a crosslinking agent, and a halogen-containing modified resin.

(16) Natural Polymer Specific examples include cellulose, rubber, proteins, or their derivatives (eg, cellulose acetate, cellulose propionate, cellulose ether) and the like.

(17) Soft Polymer Specifically, rubber-like components selected from the groups (i) to (v) described below can be mentioned.

(I) Soft Polymer Containing Cyclic Olefin Component The soft polymer containing a cycloolefin component is ethylene and
A soft polymer obtained by copolymerizing the same type of cyclic olefin (a) or (b) (formula (I) or (II)) as used in the production of the cyclic olefin resin (A). Is. This soft polymer (i) contains a cyclic olefin and ethylene as essential components, and α
-Olefin can be used within a range that does not impair the properties. Examples of the α-olefin include propylene, 1-butene, 4-methyl-1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1
-Eicosen etc. can be mentioned. Of these, α-olefins having 3 to 20 carbon atoms are preferable.
Further, cyclic olefins and cyclic dienes such as norbornene, ethylidene norbornene and dicyclopentadiene are also preferable.

In the soft polymer (i) containing a cyclic olefin component, the ethylene content is usually 40 to 98.
Mol%, preferably in the range of 50 to 90 mol%. The content of α-olefin is usually 2 to 50 mol%.
And the cyclic olefin content is usually 2 to
It is 20 mol%, preferably 2 to 15 mol%.

Unlike the cyclic olefin resin (A), this soft polymer (i) has a glass transition temperature (Tg).
Is 0 ° C. or lower, preferably −10 ° C. or lower, 1
The intrinsic viscosity [η] measured in decalin at 35 ° C. is usually 0.01 to 10 dl / g, preferably 0.8 to 7 d.
1 / g. Further, this soft polymer (i) is
The crystallinity measured by the X-ray diffraction method is usually 0 to 10
%, Preferably 0 to 7%, particularly preferably 0 to 5%.

The soft polymer (i) is described in JP-A-60-168.
708, JP 61-120816, JP 61-115912, and JP 61-11591.
6, JP-A-61-271308, JP-A-6-6
It can be produced by appropriately selecting the conditions according to the methods proposed in JP-A 1-272216, JP-A-62-252406 and JP-A-62-252406.

When the resin composition contains a polymer alloy of the cyclic olefin resin (A) and these rubber-like components, the crosslinking reaction may be carried out in the presence of an organic peroxide. The resin composition containing such a crosslinkable polymer alloy can form an electret excellent in rigidity and impact resistance.

(Ii) α-Olefin Copolymer The α-olefin copolymer (ii) used as the soft polymer is composed of at least two kinds of α-olefins and is an amorphous or low crystalline copolymer. It is a polymer. Specific examples include ethylene / α-olefin copolymers and propylene / α-olefin copolymers.

The α-olefin constituting the ethylene / α-olefin copolymer is usually one having 3 to 20 carbon atoms, and specific examples include propylene, 1-butene, 4-methyl-1-butene, Mention may be made of α-olefins such as 1-hexene, 1-octene, 1-decene and mixtures thereof. Of these, α-olefins having 3 to 10 carbon atoms are particularly preferable.

The molar ratio of ethylene / α-olefin in the ethylene / α-olefin copolymer is usually 40/60.
~ 95/5. Further, when the α-olefin is propylene, it is preferably 40/60 to 90/10, and when the α-olefin has 4 or more carbon atoms, it is 50/50 to 95/5. Is preferred.

The α-olefin constituting the propylene / α-olefin copolymer is usually one having 4 to 20 carbon atoms, and specific examples include 1-butene, 4-methyl-1-butene and 1-butene. Mention may be made of α-olefins such as hexene, 1-octene, 1-decene and mixtures thereof. Of these, α-olefins having 4 to 10 carbon atoms are particularly preferable.

The propylene / α-olefin molar ratio in this propylene / α-olefin copolymer is usually 50/50 to 95/5.

(Iii) α-Olefin / diene Copolymer As the α-olefin / diene copolymer (iii) used as the soft polymer, ethylene / α-olefin / diene copolymer rubber, propylene Examples include α-olefin / diene copolymer rubber.

The α-olefin constituting these copolymer rubbers is, for example, an α-olefin having 3 to 20 carbon atoms (4 to 20 in the case of propylene / α-olefin), specifically propylene, Examples thereof include 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and mixtures thereof. Of these, α-olefins having 3 to 10 carbon atoms are preferable.

The diene component constituting these copolymer rubbers is, for example, 1,4-hexadiene,
Chain non-conjugated dienes such as 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene, cyclohexadiene, dicyclopentadiene, Cyclic rings such as methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene Non-conjugated diene, 2,3-diisopropylidene-5
-Norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene and the like can be mentioned.

The ethylene / α-olefin / diene copolymer rubber has a molar ratio of ethylene / α-olefin of usually 40/60 to 90/10.

The content of the repeating structural unit derived from the diene component in these copolymer rubbers is
It is usually 1 to 20 mol%, preferably 2 to 15 mol%.

(Iv) Aromatic vinyl-based hydrocarbon / conjugated diene-based soft copolymer Aromatic vinyl-based hydrocarbon used as a soft polymer
The conjugated diene-based soft copolymer is a random copolymer, a block copolymer or a hydride thereof of an aromatic vinyl hydrocarbon and a conjugated diene. Specific examples include styrene / butadiene block copolymer rubber, styrene / butadiene
Butadiene / styrene block copolymer rubber, styrene / isoprene block copolymer rubber, styrene / isoprene / styrene block copolymer rubber, hydrogenated styrene / butadiene / styrene block copolymer, hydrogenated styrene / isoprene / styrene block copolymer Examples thereof include polymer rubber and styrene / butadiene random copolymer rubber.

The molar ratio of aromatic vinyl hydrocarbon / conjugated diene in these copolymer rubbers is usually 10/9.
It is 0 to 70/30. The hydrogenated copolymer rubber is a copolymer rubber obtained by hydrogenating some or all of the double bonds remaining in the above copolymer rubber.

(V) isobutylene or isobutylene
Soft polymer or copolymer composed of conjugated diene As specific examples of the isobutylene-based soft polymer or copolymer (v), polyisobutylene rubber, polyisoprene rubber, polybutadiene rubber, isobutylene / isoprene copolymer rubber and the like can be given. Can be mentioned.

The characteristics of the soft polymers (ii) to (v) are that the intrinsic viscosity [η] measured in decalin at 135 ° C. is usually 0.01 to 10 dl / g, It is preferably in the range of 0.08 to 7 dl / g, and the glass transition temperature (Tg) is usually 0 ° C or lower, preferably -10 ° C.
The temperature is particularly preferably -20 ° C or lower. The crystallinity measured by the X-ray diffraction method is usually 0 to 10%,
It is preferably in the range of 0 to 7%, particularly preferably 0 to 5%.

The resin composition for forming the electret of the present invention contains another resin in addition to the cyclic olefin resin (A) and the modified polymer compound (B) to prepare the cyclic olefin resin (A) and other resin. When a polymer alloy is formed from a resin, when the (17) soft polymer (i) to (v) is used as another resin, the soft polymer is added to 100 parts by weight of the cyclic olefin resin (A). On the other hand, it is usually used in an amount of 5 to 150 parts by weight, preferably 5 to 100 parts by weight, particularly preferably 10 to 80 parts by weight, to obtain the impact strength, rigidity, and
Good balance of properties such as heat distortion temperature and hardness.

In addition to the cyclic olefin resin (A) and the modified polymer compound (B), the resin composition may further contain a compounding agent such as a heat stabilizer, a weather stabilizer, a slip agent, if necessary. It may contain an anti-blocking agent, a lubricant, an inorganic or organic filler, a dye, a pigment and the like.

This resin composition is produced by a known method using a cyclic olefin resin (A) and a modified polymer compound (B), and optionally other resins and other additives. It can be used and mixed. For example, each component can be mixed at the same time.

The electret of the present invention can be made into various forms by using this resin composition as a raw material, molding it into various forms, and subjecting it to electret treatment.

The electretization treatment is not particularly limited and can be carried out according to various known methods. For example, a method of heating the resin composition until it is melted or softened, and cooling it while applying a high DC voltage to form an electret (thermal electret method); after molding the resin composition into a film, the surface of the film is formed. Method of applying corona discharge or pulsed high voltage, holding both sides of the film with a dielectric, and applying DC high voltage to both sides to make them electret (electro electret method); γ-ray or electron beam irradiate electret The method (radio electret method) and the like can be mentioned. More specifically,
Examples of the method include a method in which the resin composition is formed into a film and then corona discharge is applied while stretching the film as needed, a method in which the film is sandwiched between a pair of needle-shaped electrodes and a corona discharge is performed, and the like. When stretching is performed, uniaxial stretching or biaxial stretching may be performed.

The electret of the present invention is, for example, a roller.
In the case of products manufactured by N-discharge, usually 10 × 1
0^-9~ 50 × 10^-9C / cm²Degree, preferably 20x
10 ^-9~ 40 × 10^-9C / cm²Surface charge density
I have.

The electret of the present invention can be made into various forms, and the form can be appropriately selected according to the application, the mode of use and the like. For example, various forms such as a film, a sheet, a fiber and a non-woven fabric can be used.

For example, in order to electretize a nonwoven fabric formed from the above resin composition, a melt blow method,
It is produced by electretizing a nonwoven fabric obtained by a known synthetic resin nonwoven fabric production method such as a spun bond method. In the present invention, a discontinuous fiber having a fine fiber diameter is formed from a resin composition, and a non-woven fabric (melt blow method) is formed by accumulating this fiber on a porous support, and then the obtained non-woven fabric is electretized. Preferably. Hereinafter, an example of producing an electretized nonwoven fabric by the melt blow method will be described more specifically.

First, the resin composition is supplied to an extruder or the like, heated, melted and kneaded, and extruded as a fine resin stream from a melt-blowing die having a large number of pores. The extruded resin stream is contacted with a high-speed heated gas stream, cooled and solidified to form discontinuous fibers having a fine fiber diameter. The melting and kneading of the resin composition is preferably carried out at a temperature at which the resin composition does not have a low molecular weight due to thermal decomposition and has a melt viscosity suitable for melt molding, and usually 200 to 400 ° C., especially 220 to 400 ° C. It is desirable to carry out at a temperature of 380 ° C.

The die width of the melt-blowing die is usually 1
Although it is 000 to 2000 mm, the tip lip portion has a large number of pores, and is usually 800 to 300 mm.
Zero holes are drilled. The diameter of this hole is usually 0.5
It is about mm. The molten resin flow is preferably extruded from this die at a discharge rate of usually about 10 to 130 kg / hr.

The fine resin flow extruded from the die as described above is divided by being brought into contact with a high-speed heating gas flow, and is also drafted in a molten state and stretched in the fiber length direction to further increase the fiber diameter. It is made fine and formed into fine discontinuous fibers. To blow a heated gas stream onto the resin stream,
The resin flow may be extruded while blowing the heated gas flow from the air outlet provided inside the die tip lip portion, or the heated gas flow may be blown from the outside of the lip portion to the resin flow extruded from the die. . This heating gas may be air or an inert gas. The temperature of the heated gas stream is usually 20
0 to 360 ° C., particularly 230 to 330 ° C. is desirable. It is desirable that the heated gas flow is normally blown at a flow rate of 100 to 3500 m ³ / hr, particularly 200 to 3200 m ³ / hr.

The above-mentioned fine discontinuous fibers are then accumulated on a porous support to form a web-like meltblown nonwoven fabric. As this porous support, for example, a mesh structure formed of stainless steel, polyester or the like can be used. The weight of non-woven fabric is usually 5
To 100 g / m ² and it is particularly desirable that 10 to 80 g / m ^2. With such a basis weight, it is possible to obtain a non-woven fabric having appropriate breathability, locally varying the basis weight and excellent in strength. The average fiber diameter of the fibers forming the nonwoven fabric is 0.5 to 10 μm, especially 1 to 6 μm,
The fiber length is preferably about 50 to 400 mm.
This average fiber diameter is the electron micrograph (50
It was determined as an average value of the fiber diameters of any 30 fibers measured above. Nonwoven fabric formed from the above fibers,
It has excellent breathability as well as dust collection for fine dust. The bulk density of the non-woven fabric is 0.05 to 0.40 g / cm ^3, particularly 0.0, from the viewpoints of strength, ease of handling, breathability and the like.
It is preferably 6 to 0.20 g / cm ³ . The thickness of the non-woven fabric is determined by the basis weight and the bulk density, but it is usually preferably 0.1 to 5 mm, particularly 0.1 to 0.6 mm. The intrinsic viscosity [η] of the resin composition (fiber) forming the non-woven fabric is preferably 0.30 to 0.40 dl / g.

The electret according to the present invention is obtained by subjecting the non-woven fabric thus obtained to electret treatment by the method as described above. For example, when a direct current voltage is not applied to the nonwoven fabric, the direct current voltage value is appropriately selected according to the shape of the electrodes used, the distance between the electrodes, the processing speed, the desired charge amount, and the distance between the electrodes is 20.
In the case of mm, at least -10 kV, preferably -15
It is desirable to apply a DC voltage of -30 kV to the nonwoven fabric. In the present invention, the average surface charge density (amount) of the electret made of such a nonwoven fabric is usually 0.5 to 5 ×.
It is preferably about 10 ⁻⁹ C (clone) / cm ² .

The electret according to the present invention may be used as it is, or may be used by laminating a reinforcing layer and the like. Further, it can be used after being subjected to processing such as pleating, and it is preferable that a reinforcing layer or the like is laminated when such processing is performed. The reinforcing layer can be formed of woven fabric, non-woven fabric, net, paper or the like made of synthetic resin such as polyethylene terephthalate, nylon and polypropylene.

Since the electret of the present invention has a high surface charge density and is excellent in retaining the surface charge density at high temperatures, it is a material for audio equipment such as microphones, pickups and speakers; electronic copying and printing applications; It is suitable as a medical material, particularly a material for a medical device that comes into contact with blood. In particular, it is suitable as a material for electret filters used for air filters and the like.

Particularly when the electret according to the present invention is formed of a non-woven fabric, it has an excellent surface charge density retention property under high temperature and high humidity, and when used as a filter, it has a long collection performance. Therefore, the electret made of the non-woven fabric according to the present invention is particularly suitable for use in air filters such as air conditioners, air purifiers, vacuum cleaners, fan heaters and air filters for automobiles. In addition, this electret (nonwoven fabric) has excellent collection performance, so it does not suffocate even when worn as a mask for a long time, and is suitable as an industrial or household air mask that removes fine dust, bacteria, bacteria such as viruses. Can be used.

[0131]

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

(Example 1) Ethylene and tetracyclo [4.
4.0.1 ^{2,5.1 7,10} ] -3-Random copolymer with dodecene (abbreviated as TCD) (glass transition temperature (Tg) 80 ° C., specific gravity 1.02, MFR (ASTM D1238): 40 g /
10 min (hereinafter this copolymer is abbreviated as TCD-A) 9
5 parts by weight and 5 parts by weight of polypropylene graft-modified with maleic anhydride (graft ratio with maleic anhydride: 3% by weight), simultaneously with an extruder having a diameter of 40 mmφ (Japan Steel Works, L / D = 40). And was heated and melted at 250 ° C. to obtain resin pellets.

The resin pellets thus obtained were supplied to an inflation film molding machine (manufactured by Toshiba Machine Co., Ltd., 30 mmφ extruder, 80 mmφ die), and the molding temperature was 250.
The film was molded under the molding conditions of ℃, extruder screw rotation speed: 54 rpm, and a film having a folding diameter of 110 mm and a thickness of 30 μm was manufactured.

From this film, 80 mm x 220 mm
A sample having a size of was cut out. This sample was placed on the ground electrode of a charge applying device composed of a needle electrode connected to a DC high-voltage power supply (Matsusada Precision Device Co., Ltd.) and a stainless steel plate ground electrode, and the temperature was 25 ° C., the voltage was −7 KV, and the charging time was The charging process was performed for 30 seconds under the condition that the distance between the electrodes was 10 mm. Then, both surfaces were short-circuited with an aluminum plate to remove unstable surface charges, and then left at room temperature (about 25 ° C.) for 1 hour to obtain an electret. The surface charge density of this electret was measured by a surface charge density measuring instrument (manufactured by RIKEN) to obtain the initial surface charge density.

Further, this electret was heated to a temperature of 60.
After standing still in a thermo-hygrostat (LHL-111 manufactured by Tabai Co., Ltd.) kept at 80 ° C. and a relative humidity of 80% for 24 hours, it was cooled to room temperature, and after standing for 24 hours by a surface charge density measuring instrument. The surface charge density was measured. From the surface charge density after standing for 24 hours and the initial surface charge density, the surface charge retention rate 1 was calculated according to the following formula. Retention rate = [(surface charge density after standing) / (initial surface charge density)] × 100 (%)

Similarly, the electret is heated to a temperature of 80 ° C.
Constant temperature and humidity machine maintained at 90% relative humidity (LH manufactured by Tabai
L-111) was allowed to stand for 24 hours, cooled to room temperature, and the surface charge density after standing for 24 hours was measured with a surface charge density measuring device. From the surface charge density after standing for 24 hours and the initial surface charge density, the surface charge retention rate 2 was obtained according to the above formula. As a result, it was found that the surface charge density retention rate at high temperatures was high. The results are shown in Table 1.

(Comparative Example 1) A film was formed in the same manner as in Example 1 using only ETCD-A, which is the copolymer of ethylene and cyclic olefin used in Example 1, to produce an electret. The retention rates 1 and 2 of the surface charge density of the obtained electret were measured in the same manner as in Example 1. As a result, it was found that the surface charge density retention rate at high temperatures was low. The results are shown in Table 1.

Comparative Example 2 Polypropylene (MFR: 0.5 g / 10 mi) was used instead of the cyclic olefin resin.
n) An electret was produced in the same manner as in Example 1 except that 95% by weight was used. The retention rates 1 and 2 of the surface charge density of the obtained electret were measured in the same manner as in Example 1. As a result, it was found that the surface charge density retention rate at high temperatures was low. The results are shown in Table 1.

Example 2 90% by weight of ETCD-A,
An electret was produced in the same manner as in Example 1 using a resin composition containing 10% by weight of maleic anhydride graft-modified polyethylene (maleic anhydride graft ratio: 2.22% by weight). The retention rates 1 and 2 of the surface charge density of the obtained electret were measured in the same manner as in Example 1. As a result, it was found that the surface charge density retention rate at high temperatures was high. The results are shown in Table 1.

Example 3 A resin composition containing 95% by weight of ETCD and 5% by weight of ETCD-A grafted with maleic anhydride (maleic anhydride graft ratio: 0.69% by weight) was used. An electret was produced in the same manner as in 1. The retention rates 1 and 2 of the surface charge density of the obtained electret were measured in the same manner as in Example 1. As a result, it was found that the surface charge density retention rate at high temperatures was high. The results are shown in Table 1.

Example 4 90% by weight of ETCD-A,
An electret was produced in the same manner as in Example 1 using a resin composition containing 10% by weight of ETCD-A graft-modified with maleic anhydride (maleic anhydride graft ratio: 0.69% by weight). The retention rates 1 and 2 of the surface charge density of the obtained electret were measured in the same manner as in Example 1. As a result, it was found that the surface charge density retention rate at high temperatures was high. The results are shown in Table 1.

Example 5 Random copolymer of ethylene and norbornene (Tg 80 ° C., specific gravity 1.02, MFR
(ASTM D1238): 40g / 10min) 90
An electret was prepared in the same manner as in Example 1 using a resin composition containing 10% by weight of propylene (PP) graft-modified with maleic anhydride (maleic anhydride graft ratio: 0.69% by weight). Manufactured. The retention rates 1 and 2 of the surface charge density of the obtained electret were measured in the same manner as in Example 1. As a result, it was found that the surface charge density retention rate at high temperatures was high. The results are shown in Table 1.

Example 6 75% by weight of ETCD-A,
An electret was produced in the same manner as in Example 1 using a resin composition containing 25% by weight of ETCD-A graft-modified with maleic anhydride (maleic anhydride graft ratio: 0.69% by weight). The retention rates 1 and 2 of the surface charge density of the obtained electret were measured in the same manner as in Example 1. As a result, it was found that the surface charge density retention rate at high temperatures was high. The results are shown in Table 1.

Comparative Example 3 Polypropylene (MFR:
Example 1 except that only 0.5 g / 10 min) was used.
An electret was manufactured in the same manner as in. The surface charge density retention rates 1 and 2 of the obtained electret were measured in the same manner as in Example 1. As a result, it was found that the surface charge density retention rate at high temperatures was low. The results are shown in Table 1.

[0145]

[Table 1]

(Example 7) (A) Ethylene and tetracyclo [4.4.
0.1 ^2,5 .1 ^7,10] -3-random copolymer of dodecene (hereinafter abbreviated to as ETCD-B) :( specific gravity 1.04 (AST
M D792), MFR 150g / 10min (ASTM D
1238, 260 ° C.), Tg 120 ° C.) 97% by weight,
(B) ETCD-B graft-modified with maleic anhydride as a modified polymer compound (maleic anhydride graft modification rate: 0.69% by weight) was mixed with a tumbler blender to prepare a resin composition. The obtained resin composition,
It is charged into a 65 mmφ single-screw extruder, melted at 350 ° C., extruded at a discharge rate of 20 kg / hr from a melt-blowing die connected to the tip of the extruder, and a take-up speed of 13 m.
The melt blown non-woven fabric was formed by taking it off at a flow rate of 1 / min. The melt-blowing die used had a die width of 1.3 m, and two rows of molding holes were opened over the entire width of the die. Also, heated air at 320 ° C. was injected into the melt-blowing die at a flow rate of 500 m ³ / hr.

The melt-blown nonwoven fabric obtained as described above had a thickness of 0.25 mm and a basis weight of 20 g / m 2.
² and the bulk density was 0.085 g / cm ³ . The fibers constituting this nonwoven fabric were observed with a microscope to measure the average fiber diameter, which was 4 μm. The intrinsic viscosity [η] of the resin forming the fiber was 0.37 dl / g.

While applying a DC voltage of −18 kV to the electrodes having needle electrodes arranged in two rows at intervals of 12 mm in the length direction, the nonwoven fabric obtained above was continuously treated at a speed of 20 m / min. The non-woven fabric was electretized. The average surface charge of the obtained electret (nonwoven fabric) was measured and found to be 1.2 × 10 ⁻⁹ coulomb / cm ²
Met. The average surface charge amount was measured using the same surface charge density measuring device as in Example 1 by bringing an electrode probe having an area of 1 cm ² into contact with the nonwoven fabric surface.

30 × from this electret (nonwoven fabric)
Five 30 cm samples were cut out to form a filter, and the collection efficiency was measured according to the following method. In addition, after putting this filter in a thermo-hygrostat having a temperature of 80 ° C and a humidity of 90% for 24 hours, taking it out, conditioning it in a room of a temperature of 23 ° C and a humidity of 50% for 1 hour, and then similarly measuring the collection efficiency. did.
The measurement result was displayed as 5 measurement values at each time. Table 2 shows the results.

[Measurement of Collection Efficiency] The collection efficiency was measured using the apparatus schematically shown in FIG. First, from an aerosol generator (Nippon Kagaku Kogyo Co., Ltd.) 1 to NaCl particles (particle size:
3 μm), and the clean air passed through the air filter 2 was supplied to the chamber 3. Chamber 3
The concentration of NaCl particles inside is constant (2-6 × 10 ⁶ )
After that, the blower 4 was operated to suck the gas in the chamber 3 through the flow path 5 while adjusting the flow rate with the flow rate adjusting valve 6. When the flow velocity measured by the anemometer 7 becomes a constant velocity (0.5 m / sec),
The NaCl particle concentrations Cin and Cout on the upstream side and the downstream side of the electret filter 8 to be measured, which were arranged in the distribution path 5, were measured by particle counters (KC-01B manufactured by Rion Co., Ltd.) 9a and 9b, respectively. The collection efficiency was calculated based on the following formula. The pressure loss (mmAg) at this time was measured by the differential pressure gauge 10. Collection efficiency = [1- (Cout / Cin)] × 100 (%)

Example 8 In Example 7, (A) /
Example 7 except that the compounding ratio of (B) was changed to 95/5.
An electretized non-woven fabric was produced in the same manner as in 1. and further a filter was prepared. The obtained filter had a bulk density of 0.091 g / cm ³ and an average surface charge density of 1.4 × 10 ^-9.
Coulomb / cm ² , intrinsic viscosity of the resin that forms the fiber [η]
Was 0.40 dl / g and the average fiber diameter was 4 μm. The collection efficiency of this filter was measured in the same manner as in Example 7. Table 2 shows the results.

(Comparative Example 4) In Example 7, the modified polymer compound (B) was not used, and ETCD was used as the resin of (A).
An electretized nonwoven fabric was produced in the same manner as in Example 1 except that only -B was used, and a filter was further produced. The bulk density of the obtained filter is 0.086 g / c.
m ³ , average surface charge density is 0.9 × 10 ^-9 coulomb / c
m ² , the intrinsic viscosity [η] of the resin forming the fiber is 0.40 dl
/ G, the average fiber diameter was 4 μm. The collection efficiency of this filter was measured in the same manner as in Example 7. Table 2 shows the results
Shown in

(Comparative Example 5) In Example 7, polypropylene [specific gravity 0.91 (D792), MFR 800 g / 1
0 minutes (ASTM D1238, 230 ° C) 97% by weight
And a maleic anhydride graft-modified polypropylene (maleic anhydride graft ratio 2.7% by weight) 3% by weight except that a resin composition was used to produce an electretized nonwoven fabric in the same manner as in Example 1 Created a filter. The bulk density of the obtained filter is 0.085 g / c.
m ³ , average surface charge density is 1.2 × 10 ^-9 coulomb / c
m ² , the intrinsic viscosity [η] of the resin forming the fiber is 0.58 dl
/ G, the average fiber diameter was 4 μm. The collection efficiency of this filter was measured in the same manner as in Example 7. Table 2 shows the results
Shown in

(Comparative Example 6) In Example 7, instead of the resin composition, polypropylene [specific gravity 0.91 (D79
2), MFR is 800 g / 10 minutes (ASTM D 12
38, 230 ° C.)] was used, an electretized nonwoven fabric was produced in the same manner as in Example 1, and a filter was further produced. The bulk density of the obtained filter is 0.
The average surface charge density was 086 g / cm ³ , the average surface charge density was 0.9 × 10 ^-9 coulomb / cm ² , the intrinsic viscosity [η] of the resin forming the fiber was 0.60 dl / g, and the average fiber diameter was 4 μm. The collection efficiency of this filter was measured in the same manner as in Example 7.
Table 2 shows the results.

[0155]

[Table 2]

[0156]

INDUSTRIAL APPLICABILITY The electret of the present invention has a high charge density even at room temperature or high temperature, and is excellent in various properties such as excellent retention of the surface charge density.

[Brief description of drawings]

FIG. 1 shows an aerosol generator used for measuring collection efficiency in Examples of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location D06M 10/00 // D06M 101: 20

Claims (8)

[Claims] 1. A modified polymer compound (B) obtained by graft-copolymerizing a cyclic olefin resin (A) and a polymer compound with at least one modified monomer selected from unsaturated carboxylic acids and derivatives thereof. An electret composed of a resin composition containing and. 2. The electret according to claim 1, wherein in the modified polymer compound (B), the graft amount of the modified monomer is 0.05 to 15% by weight. 3. A resin composition comprising 100 parts by weight of a cyclic olefin resin (A) and a modified polymer compound (B).
The composition according to claim 1 or 2, which comprises 0.5 to 40 parts by weight.
The electret described in. 4. A modified polymer compound (B) comprising a resin composition based on 100 parts by weight of a cyclic olefin resin (A).
The electret according to claim 1 or 2, which comprises 2 to 15 parts by weight. 5. The electret according to any one of claims 1 to 4, wherein the modified polymer compound (B) is a modified α-olefin (co) polymer or a modified cyclic olefin resin. 6. The electret according to claim 1, wherein the electret is in the form of a film. 7. The electret according to any one of claims 1 to 5, wherein the electret is made of a non-woven fabric formed from single fibers of the resin composition. 8. An electret is made of a non-woven fabric having an average fiber diameter of single fibers of 0.5 to 100 μm, a basis weight of 5 to 100 g / m ² , and a bulk density of 0.05 to 0.40 g / cm ³ .
The electret according to claim 7, which has an average surface charge density of 0.1 × 10 ^-9 coulomb / cm ² or more.