阅读说明：本技术 无纺布和过滤器 (Nonwoven fabric and filter ) 是由 宫泽慎介 于 2019-02-15 设计创作，主要内容包括：本发明提供了一种无纺布,其能够实现高收集率、低压力损失和能够长期使用的过滤器。本发明的无纺布由含有结晶性的含脂环式结构树脂的纤维形成,用泡点法测定的孔径为5μm以下。(The present invention provides a nonwoven fabric capable of realizing a filter which is high in collection rate, low in pressure loss, and capable of being used for a long period of time. The nonwoven fabric of the present invention is formed from fibers containing a crystalline alicyclic structure-containing resin, and has a pore diameter of 5 μm or less as measured by the bubble point method.)

1. A nonwoven fabric comprising a fiber containing a crystalline alicyclic structure-containing resin,

the pore diameter measured by the bubble point method is 5 μm or less.

2. The nonwoven fabric according to claim 1, wherein the crystalline alicyclic structure-containing resin is a hydrogenated dicyclopentadiene ring-opening polymer having stereoregularity.

3. A filter having the nonwoven fabric according to claim 1 or 2.

4. The filter according to claim 3, which is a filter for manufacturing a semiconductor element used for manufacturing a semiconductor element.

Technical Field

The present invention relates to a nonwoven fabric and a filter.

Background

Cyclic Olefin Polymers (COPs) are widely used in the fields of optical materials, automobile parts, motors/electronic parts, and the like as materials having a balance among various properties such as heat resistance, low water absorption, low dielectric properties, and the like. Further, in view of the excellent properties of the cyclic olefin polymer, application to fibers and nonwoven fabrics has been proposed.

For example, the following protocol was studied: a nonwoven fabric using fibers having excellent heat resistance, chemical stability, and strength is obtained by melt-spinning a cyclic olefin resin having characteristics such as a large content of cyclic olefin units and a high glass transition temperature at a non-drawing ratio or a low drawing ratio (see, for example, patent document 1).

Disclosure of Invention

Problems to be solved by the invention

In recent years, it has been desired to efficiently collect fine particles generated in a process of manufacturing a semiconductor device such as a semiconductor chip.

Here, when the nonwoven fabric disclosed in patent document 1 is used as a filter for collecting fine particles, if the collection property is to be improved, it is not sufficient in terms of increase in pressure loss and in terms of the need to replace the filter in a short time, and there is still room for further improvement.

Accordingly, an object of the present invention is to provide a nonwoven fabric that can realize a filter having a high collection efficiency, a low pressure loss, and a long-term use, and a filter having the nonwoven fabric.

Means for solving the problems

The nonwoven fabric of the present invention is formed from fibers containing a crystalline alicyclic structure-containing resin as a cyclic olefin polymer, and has a pore diameter of 5 μm or less as measured by the bubble point method. As described above, when the nonwoven fabric is formed of fibers containing a crystalline alicyclic structure-containing resin and has a pore diameter of 5 μm or less as measured by the bubble point method, it is possible to realize a filter having a high collection rate, a low pressure loss and capable of being used for a long period of time.

The "crystalline alicyclic structure-containing resin" means "an alicyclic structure-containing resin having a melting point Tm (i.e., an alicyclic structure-containing resin whose melting point can be observed by a Differential Scanning Calorimeter (DSC)"). Here, the "melting point of the crystalline alicyclic structure-containing resin" can be measured by a differential scanning calorimetry method according to jis k 7121.

The "presence or absence of crystallinity" can be judged by the presence or absence of a melting point, and if the melting point is present, crystallinity is present.

Further, the "pore diameter measured by the bubble point method" means that the nonwoven fabric is immersed in a liquid (e.g., isopropyl alcohol) to increase the gas pressure, bubbles are first generated from the pores having the largest pore diameter, and the maximum pore diameter D calculated by the following formula (1) is used based on the pressure (bubble point pressure) at the time of generation of the bubbles_BP(μm)。

D_BP＝(4γcosθ/P)×10^-6…(1)

In formula (1), γ represents the surface tension (N/m) of the liquid, θ represents the contact angle (rad) of the liquid with the nonwoven fabric, and P represents the bubble point pressure (Pa).

In the nonwoven fabric of the present invention, the crystalline alicyclic structure-containing resin is preferably a hydrogenated dicyclopentadiene ring-opening polymer having stereoregularity. If the crystalline alicyclic structure-containing resin is a hydrogenated dicyclopentadiene ring-opening polymer having stereoregularity, a filter having a high collection rate, a low pressure loss and capable of long-term use can be more reliably realized.

Further, the present invention has an object to advantageously solve the above-mentioned problems, and the filter of the present invention is characterized by having any one of the nonwoven fabrics described above. According to the filter having any one of the nonwoven fabrics described above, a high collection rate, a low pressure loss, and a long-term use can be achieved.

Here, the filter of the present invention is preferably a filter for manufacturing a semiconductor element used for manufacturing a semiconductor element. If the filter is a filter for manufacturing a semiconductor element, it is possible to efficiently collect particles generated in a manufacturing process of a semiconductor element such as a semiconductor chip.

Effects of the invention

According to the present invention, a nonwoven fabric capable of realizing a filter having a high collection efficiency, a low pressure loss, and a long-term use, and a filter having the nonwoven fabric can be provided.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. Here, the nonwoven fabric and the filter of the present invention can be preferably used for efficiently collecting fine particles generated in, for example, a manufacturing process of a semiconductor element such as a semiconductor chip.

(nonwoven fabrics)

The nonwoven fabric of the present invention is formed from fibers containing a crystalline alicyclic structure-containing resin. The nonwoven fabric of the present invention has a pore diameter of 5 μm or less as measured by the bubble point method.

< crystalline alicyclic structure-containing resin >

In the present specification, the "crystalline alicyclic structure-containing resin" refers to a polymer having an alicyclic structure in the molecule and having crystallinity, which is obtained by polymerizing a cyclic olefin. The crystalline alicyclic structure-containing resin may be hereinafter referred to as "polymer (α)". Here, in the present specification, the term "having crystallinity" means that the melting point can be detected by measurement according to the Differential Scanning Calorimetry (DSC) method of jis k 7121. The "crystallinity" of a polymer is an inherent property of a polymer having a specific structure due to the stereoregularity of polymer chains.

Polymer (alpha) -

The polymer (α) is not particularly limited, but is preferably a hydrogenated product of a norbornene ring-opening polymer. More specifically, as the polymer (α), known polymers such as hydrogenated dicyclopentadiene ring-opening polymer having syndiotactic stereoregularity described in International publication No. 2012/033076, hydrogenated dicyclopentadiene ring-opening polymer having isotactic stereoregularity described in Japanese patent laid-open publication No. 2002-249553, hydrogenated norbornene ring-opening polymer described in Japanese patent laid-open publication No. 2007-16102, and the like can be used. If the polymer (α) is a hydrogenated product of a norbornene ring-opening polymer, the chemical resistance can be improved.

The melting point of the polymer (α) is not particularly limited, but is preferably 110 ℃ or higher, more preferably 200 ℃ or higher, further preferably 220 ℃ or higher, particularly preferably 250 ℃ or higher, and further preferably 350 ℃ or lower, more preferably 320 ℃ or lower, further preferably 300 ℃ or lower, and particularly preferably 270 ℃ or lower.

By using a polymer (α) having a melting point of not less than the lower limit, a fiber having excellent heat resistance can be obtained. Further, by using the polymer (α) having a melting point of not more than the above upper limit, fibers can be efficiently produced.

The glass transition temperature of the polymer (α) is not particularly limited, but is preferably 85 ℃ or higher, more preferably 87 ℃ or higher, further preferably 90 ℃ or higher, particularly preferably 95 ℃ or higher, and further preferably 170 ℃ or lower, more preferably 150 ℃ or lower, further preferably 130 ℃ or lower, and particularly preferably 105 ℃ or lower.

By using the polymer (α) having a glass transition temperature of not less than the lower limit, a nonwoven fabric having excellent heat resistance can be obtained. Further, by using the polymer (α) having a glass transition temperature of not more than the above upper limit, a nonwoven fabric having excellent moldability can be obtained.

Among them, hydrogenated dicyclopentadiene ring-opening polymers having syndiotactic stereoregularity (hereinafter, sometimes referred to as "polymers (α 1)") are preferable as the polymers (α) in terms of easily obtaining nonwoven fabrics that can realize filters having high collection efficiency, low pressure loss and long-term use. Here, the dicyclopentadiene ring-opening polymer hydride is a hydride of a ring-opening polymer containing a monomer unit derived from a dicyclopentadiene type. Further, when the total content of the hydrogenated dicyclopentadiene ring-opening polymer is 100% by mass, the content of the dicyclopentadiene-derived monomer units in the hydrogenated dicyclopentadiene ring-opening polymer is preferably more than 90% by mass, more preferably more than 95% by mass.

The degree of stereoregularity of the polymer (α 1) is not particularly limited, and a polymer having a high degree of stereoregularity is preferable as the polymer (α 1) from the viewpoint that a fiber having high heat resistance and chemical resistance can be easily obtained.

Specifically, the proportion (isotactic/syndiotactic ratio) of the syndiotactic diad (Racemo diad) in the repeating unit is preferably 51% or more, more preferably 60% or more, further preferably 65% or more, particularly preferably 70% or more, and most preferably 80% or more.

The higher the ratio of syndiotactic diads, that is, the higher the syndiotactic stereoregularity, the more the hydrogenated dicyclopentadiene ring-opening polymer having a high melting point is obtained.

The ratio of syndiotactic diad group can be based on the description of the embodiments in this specification¹³C-NMR spectroscopic analysis.

The polymer (. alpha.1) can be prepared by the following method: ring-opening polymerization is performed using a dicyclopentadiene-based monomer composition (hereinafter also referred to as "monomer composition (α 1)") such as dicyclopentadiene, methyldicyclopentadiene, or 5, 6-dihydrodicyclopentadiene to obtain a ring-opened polymer, and at least a part of unsaturated bonds present in the obtained ring-opened polymer is hydrogenated. Here, when the total monomers contained in the monomer composition (α 1) is defined as 100% by mass, the content of the dicyclopentadiene is preferably more than 90% by mass, more preferably more than 95% by mass, and particularly preferably 100% by mass. The monomer composition (α 1) may contain other monomers than dicyclopentadiene, and examples thereof include, but are not particularly limited to, norbornenes other than dicyclopentadiene, cyclic olefins, and dienes as long as the monomers are copolymerizable with the dicyclopentadiene.

Furthermore, in dicyclopentadiene, stereoisomers such as an endo form and an exo form exist. As the dicyclopentadiene added to the monomer composition (α 1), any of an endo form and an exo form can be used. Here, the dicyclopentadiene compound may include only either of the endo form and the exo form. Alternatively, a mixture of stereoisomers of dicyclopentadiene type in which the internal form and the external form are mixed at an arbitrary ratio may be added to the monomer composition (. alpha.1). Among them, from the viewpoint of improving the heat resistance and chemical resistance of the obtained semiconductor container, it is preferable that either of the inner and outer molded bodies is contained in a proportion of the dicyclopentadiene-based main component. In other words, when the content of the total dicyclopentadiene compounds contained in the monomer composition (. alpha.1) is 100% by mass, the proportion of either the inner form or the outer form is preferably more than 50% by mass. Further, the proportion of the stereoisomer which is the main component of the dicyclopentadiene-based monomer composition (α 1) is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 97% by mass or more. In addition, from the viewpoint that the dicyclopentadiene-based endo form is easier to synthesize than the exo form, it is preferable that the proportion of the endo form is higher than that of the exo form in the dicyclopentadiene-based monomer composition (. alpha.1).

The ring-opening polymerization catalyst used for synthesizing the polymer (α) is not particularly limited as long as it is a ring-opening polymerization catalyst capable of ring-opening polymerizing dicyclopentadiene to obtain a ring-opened polymer having a syndiotactic stereoregularity. As a preferred ring-opening polymerization catalyst, a catalyst containing a metal compound represented by the following formula (1) can be mentioned.

M(NR¹)X_4-a(OR²)_a·L_b……(1)

In the above formula (1), M is a metal atom selected from transition metal atoms of group 6 of the periodic Table of the elements, R¹Is phenyl which may have a substituent at least 1 of the 3,4,5 positions, or-CH₂R³(R³Is a hydrogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent. ) A group represented by, R²Is a group selected from an alkyl group which may have a substituent and an aryl group which may have a substituent, X is a group selected from a halogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent and an alkylsilyl group, and L is an electron-donating neutral ligand. a is 0 or 1, and b is an integer of 0 to 2.

M is a transition metal atom of group 6 of the periodic Table (chromium, molybdenum, tungsten), preferably molybdenum or tungsten, more preferably tungsten.

R¹The number of carbon atoms of the phenyl group which may have a substituent at least 1 of the 3,4 or 5 positions is not particularly limited, but is preferablyPreferably 6 or more, and more preferably 20 or less, and still more preferably 15 or less.

Examples of the substituent include: alkyl groups such as methyl and ethyl; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, etc.; alkoxy groups such as methoxy, ethoxy, and isopropoxy.

Further, substituents present at least 2 of the 3-, 4-and 5-positions may be bonded to each other to form a ring structure.

Examples of the phenyl group which may have a substituent at least 1 of the 3-, 4-and 5-positions include: unsubstituted phenyl; a mono-substituted phenyl group such as a 4-methylphenyl group, a 4-chlorophenyl group, a 3-methoxyphenyl group, a 4-cyclohexylphenyl group, or a 4-methoxyphenyl group; disubstituted phenyl groups such as 3, 5-dimethylphenyl, 3, 5-dichlorophenyl, 3, 4-dimethylphenyl, 3, 5-dimethoxyphenyl and the like; trisubstituted phenyl groups such as 3,4, 5-trimethylphenyl and 3,4, 5-trichlorophenyl; 2-naphthyl which may have a substituent such as 2-naphthyl, 3-methyl-2-naphthyl and 4-methyl-2-naphthyl.

At R¹Of (C-CH)₂R³In the group represented, R³Represents a group selected from a hydrogen atom, an alkyl group which may have a substituent, and an aryl group which may have a substituent.

R³The number of carbon atoms of the alkyl group which may have a substituent(s) of (1) is not particularly limited, but is preferably 1 or more, and is preferably 20 or less, more preferably 10 or less, and particularly preferably 4 or less. The alkyl group may be linear or branched.

Examples of the substituent include: phenyl groups which may have a substituent such as phenyl group and 4-methylphenyl group; alkoxy groups such as methoxy and ethoxy.

As R³Examples of the alkyl group which may have a substituent(s) of (1) include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a benzyl group, a 2-methyl-2-phenylpropyl group (neophyl group), and the like.

R³The number of carbon atoms of the aryl group which may have a substituent(s) of (2) is not particularly limited, but is preferably 6 or more, and is preferably 20 or less, and more preferably 15 or less.

Examples of the substituent include an alkyl group such as a methyl group or an ethyl group; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, etc.; alkoxy groups such as methoxy, ethoxy, and isopropoxy.

As R³Examples of the aryl group which may have a substituent include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 4-methylphenyl group, a 2, 6-dimethylphenyl group and the like.

Among these, as R³The group is preferably an alkyl group having 1 to 20 carbon atoms.

Examples of the halogen atom of X include a chlorine atom, a bromine atom and an iodine atom.

Examples of the optionally substituted alkyl group and the optionally substituted aryl group for X include³The same groups as those shown for the alkyl group which may have a substituent and the aryl group which may have a substituent are given.

Examples of the alkylsilyl group of X include a trimethylsilyl group, a triethylsilyl group, and a t-butyldimethylsilyl group.

Further, when the metal compound represented by the formula (1) has 2 or more xs, they may be bonded to each other to form a ring structure.

As R²The optionally substituted alkyl group and the optionally substituted aryl group of (1) may be respectively mentioned as R³The same groups as those shown for the alkyl group which may have a substituent and the aryl group which may have a substituent are given.

Examples of the electron-donating neutral ligand of L include electron-donating ligands containing atoms of group 15 or group 16 of the periodic table. Specific examples thereof include: phosphines such as trimethylphosphine, triisopropylphosphine, tricyclohexylphosphine, and triphenylphosphine; ethers such as diethyl ether, dibutyl ether, 1, 2-dimethoxyethane, and tetrahydrofuran; and amines such as trimethylamine, triethylamine, pyridine, and lutidine. Among these, ethers are preferred.

As the metal compound represented by the formula (1), a tungsten compound having a phenylimide group (M in the formula (1) is a tungsten atom, R is preferably used¹A compound that is a phenyl group), more preferably tetrachlorotunghenylimide (tetrahydrofuran)Pyran) complexes.

The method for synthesizing the metal compound represented by the formula (1) is not particularly limited, and examples thereof include the method described in Japanese patent laid-open No. 5-345817. That is, the target metal compound can be synthesized by mixing an oxyhalide of a group 6 transition metal, a phenylisocyanate or a mono-substituted methylisocyanate which may have a substituent at least 1 of the 3-, 4-and 5-positions, an electron donating neutral ligand (L), and an alcohol, a metal alkoxide or a metal aryloxide which may be used as needed.

After the synthesis of the metal compound, the reaction solution may be used as it is as a catalyst solution for the ring-opening polymerization reaction, or the metal compound may be separated and purified by a known purification treatment such as crystallization, and then the obtained metal compound may be supplied to the ring-opening polymerization reaction.

The ring-opening polymerization catalyst may be formed only of the metal compound represented by formula (1), or the metal compound represented by formula (1) may be combined with an organometallic reducing agent. By using the metal compound represented by the formula (1) in combination with an organometallic reducing agent, the polymerization activity is improved.

Examples of the organometallic reducing agent include organometallic compounds of groups 1,2, 12, 13 and 14 of the periodic table having a hydrocarbon group having 1 to 20 carbon atoms.

Examples of the organometallic compound include: organolithium such as methyllithium, n-butyllithium, phenyllithium and the like; organic magnesium such as butyl ethyl magnesium, butyl octyl magnesium, dihexyl magnesium, ethyl magnesium chloride, n-butyl magnesium chloride, allyl magnesium bromide, etc.; organic zinc such as dimethyl zinc, diethyl zinc, and diphenyl zinc; organoaluminum such as trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, ethoxydiethylaluminum, isobutyloxydiisobutylaluminum, diethoxyethylaluminum, diisobutylaluminum and the like; organotin such as tetramethyltin, tetra-n-butyltin, tetraphenyltin, etc.

Among these, organoaluminum or organotin is preferable.

The ring-opening polymerization reaction is usually carried out in an organic solvent. The organic solvent to be used is not particularly limited as long as it can dissolve or disperse the ring-opening polymer or the hydride thereof under predetermined conditions and does not inhibit the ring-opening polymerization reaction or the hydrogenation reaction.

Examples of the organic solvent include: aliphatic hydrocarbons such as pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, ethylcyclohexane, diethylcyclohexane, decahydronaphthalene, bicycloheptane, tricyclodecane, hexahydroindene, and cyclooctane; aromatic hydrocarbons such as benzene, toluene, and xylene; halogen-based aliphatic hydrocarbons such as methylene chloride, chloroform, and 1, 2-dichloroethane; halogen-based aromatic hydrocarbons such as chlorobenzene and dichlorobenzene; nitrogen-containing hydrocarbons such as nitromethane, nitrobenzene, acetonitrile, and the like; ethers such as diethyl ether and tetrahydrofuran; a mixed solvent containing these components in combination.

Among these, as the organic solvent, aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, and ethers are preferable.

The ring-opening polymerization reaction can be initiated by mixing the monomer, the metal compound represented by formula (1), and the organometallic reducing agent used as needed. The order of adding these components is not particularly limited. For example, a solution containing the metal compound represented by formula (1) and the organometallic reducing agent may be added to and mixed with a solution containing the monomer, a solution containing the monomer and the metal compound represented by formula (1) may be added to and mixed with a solution containing the organometallic reducing agent, or a solution containing the metal compound represented by formula (1) may be added to and mixed with a solution containing the monomer and the organometallic reducing agent.

When each component is added, the whole amount of each component may be added at one time, or may be added in a plurality of times. Further, the addition may be performed continuously over a long period of time (for example, 1 minute or more).

The concentration of the monomer at the initiation of the ring-opening polymerization reaction is not particularly limited, and is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 3% by mass or more, and is preferably 50% by mass or less, more preferably 45% by mass or less, and particularly preferably 40% by mass or less. When the concentration of the monomer is too low, productivity may be lowered, and when the concentration of the monomer is too high, the solution viscosity after the ring-opening polymerization reaction may be too high, and the subsequent hydrogenation reaction may become difficult.

The amount of the metal compound represented by the formula (1) used in the ring-opening polymerization reaction is preferably an amount such that the molar ratio of (metal compound: monomer) is 1: 100 to 1: 2000000, more preferably an amount such that the molar ratio is 1: 500 to 1: 1000000, and particularly preferably an amount such that the molar ratio is 1: 1000 to 1: 500000. When the amount of the metal compound is too large, it becomes difficult to remove the metal compound after the reaction, and when the amount of the metal compound is too small, a sufficient polymerization activity cannot be obtained.

When the organometallic reducing agent is used, the amount thereof to be used is preferably 0.1 mol or more, more preferably 0.2 mol or more, particularly preferably 0.5 mol or more, preferably 100 mol or less, more preferably 50 mol or less, and particularly preferably 20 mol or less, based on 1 mol of the metal compound represented by the formula (1). When the amount of the organometallic reducing agent used is too small, the polymerization activity cannot be sufficiently improved, and when the amount of the organometallic reducing agent used is too large, side reactions are likely to occur.

An activity modifier may be added to the polymerization reaction system. By using the activity modifier, the ring-opening polymerization catalyst can be stabilized, and the reaction rate of the ring-opening polymerization reaction and the molecular weight distribution of the polymer can be adjusted.

The activity adjuster is not particularly limited as long as it is an organic compound having a functional group. Examples of the activity adjuster include an oxygen-containing compound, a nitrogen-containing compound, and a phosphorus-containing compound.

Examples of the oxygen-containing compound include: ethers such as diethyl ether, diisopropyl ether, dibutyl ether, anisole, furan, and tetrahydrofuran; ketones such as acetone, benzophenone, and cyclohexanone; and esters such as ethyl acetate.

Examples of the nitrogen-containing compound include: nitriles such as acetonitrile and benzonitrile; amines such as triethylamine, triisopropylamine, quinuclidine and N, N-diethylaniline; pyridines such as pyridine, 2, 4-lutidine, 2, 6-lutidine and 2-t-butylpyridine.

Examples of the phosphorus-containing compound include: phosphines such as triphenylphosphine, tricyclohexylphosphine, triphenyl phosphate, and trimethyl phosphate; phosphine oxides such as triphenylphosphine oxide, and the like.

The activity regulator can be used alone in 1 kind or in combination of 2 or more kinds. The amount of the activity modifier to be added is not particularly limited, and may be selected from the range of usually 0.01 mol% to 100 mol% based on the metal compound represented by the formula (1).

In the polymerization reaction system, a molecular weight regulator for regulating the molecular weight of the ring-opened polymer may be added. Examples of the molecular weight regulator include: α -olefins such as 1-butene, 1-pentene, 1-hexene and 1-octene; aromatic vinyl compounds such as styrene and vinyl toluene; oxygen-containing vinyl compounds such as ethyl vinyl ether, isobutyl vinyl ether, allyl glycidyl ether, allyl acetate, allyl alcohol, and glycidyl methacrylate; halogen-containing vinyl compounds such as allyl chloride; nitrogen-containing vinyl compounds such as acrylamide; non-conjugated dienes such as 1, 4-pentadiene, 1, 4-hexadiene, 1, 5-hexadiene, 1, 6-heptadiene, 2-methyl-1, 4-pentadiene and 2, 5-dimethyl-1, 5-hexadiene; conjugated dienes such as 1, 3-butadiene, 2-methyl-1, 3-butadiene, 2, 3-dimethyl-1, 3-butadiene, 1, 3-pentadiene and 1, 3-hexadiene.

The molecular weight regulators can be used singly or in combination of 2 or more. The amount of the molecular weight modifier to be added may be appropriately determined depending on the target molecular weight, and may be selected in the range of 0.1 to 50 mol% with respect to dicyclopentadiene.

The polymerization temperature is not particularly limited, but is preferably-78 ℃ or higher, more preferably-30 ℃ or higher, preferably +200 ℃ or lower, and more preferably +180 ℃ or lower. The polymerization time is not particularly limited, and is usually in the range of 1 minute or more and 1000 hours or less depending on the scale of the reaction.

The weight average molecular weight (Mw) of the ring-opened polymer is not particularly limited, but is preferably 1000 or more, more preferably 2000 or more, particularly preferably 10000 or more, and further preferably 1000000 or less, more preferably 500000 or less, and particularly preferably 100000 or less. By supplying the ring-opened polymer having such a weight average molecular weight to the hydrogenation reaction, a polymer (α 1) having an excellent balance between moldability and chemical resistance can be obtained. The weight average molecular weight of the ring-opened polymer can be adjusted by adjusting the amount of the molecular weight modifier used in the polymerization, and the like.

The molecular weight distribution (Mw/Mn) of the ring-opened polymer is not particularly limited, but is usually 1.0 or more, preferably 1.5 or more, and further preferably 4.0 or less, and more preferably 3.5 or less. By supplying the ring-opened polymer having such a molecular weight distribution to the hydrogenation reaction, a polymer (. alpha.1) having excellent moldability can be obtained. The molecular weight distribution of the ring-opened polymer can be adjusted by adjusting the method of adding the monomer and the concentration of the monomer at the time of polymerization.

The weight average molecular weight (Mw) and the molecular weight distribution (Mw/Mn) of the ring-opened polymer are values in terms of polystyrene measured by Gel Permeation Chromatography (GPC) using tetrahydrofuran as a developing solvent.

The ring-opening polymerization reaction can provide a dicyclopentadiene ring-opened polymer having a syndiotactic stereoregularity. In the hydrogenation reaction carried out after the ring-opening polymerization reaction, if the reaction conditions are appropriately set, the stereoregularity of the ring-opened polymer is not generally changed by the hydrogenation reaction, and therefore the target polymer (. alpha.1) can be obtained by supplying the dicyclopentadiene ring-opened polymer having a syndiotactic stereoregularity to the hydrogenation reaction. The degree of the syndiotacticity of the ring-opening polymer can be adjusted by selecting the kind of the ring-opening polymerization catalyst, changing the amount to be used, and the like. For example, when the amount of the ring-opening polymerization catalyst used is reduced, the syndiotactic stereoregularity tends to be higher.

The hydrogenation reaction of the ring-opened polymer can be carried out by supplying hydrogen in the presence of a hydrogenation catalyst in the reaction system. As the hydrogenation catalyst, a known homogeneous catalyst or heterogeneous catalyst which is a hydrogenation catalyst for an olefin compound can be used.

Examples of homogeneous catalysts are: catalysts formed from a combination of a transition metal compound and an organoaluminum compound, such as cobalt acetate/triethylaluminum, nickel acetylacetonate/triisobutylaluminum, etc.; titanocene dichloride/n-butyllithium, zirconocene dichloride/sec-butyllithium, and the like comprising a catalyst formed of a combination of a transition metal compound and an organic alkali metal compound; tetrabutoxy titanate/dimethylmagnesium and the like catalysts formed from a combination of a transition metal compound and an organomagnesium compound; noble metal complex catalysts such as bis (triphenylphosphine) palladium dichloride, tris (triphenylphosphine) ruthenium carbonyl hydrochloride, bis (tricyclohexylphosphine) benzylidene ruthenium (IV) dichloride, tris (triphenylphosphine) rhodium chloride, and the like.

Examples of heterogeneous catalysts include: metal catalysts such as nickel, palladium, platinum, rhodium, and ruthenium; a solid catalyst in which the above metal is supported on a carrier such as carbon, silica, diatomaceous earth, alumina, or titania, such as nickel/silica, nickel/diatomaceous earth, nickel/alumina, palladium/carbon, palladium/silica, palladium/diatomaceous earth, or palladium/alumina.

The hydrogenation reaction is usually carried out in an inert organic solvent. Examples of the inert organic solvent include: aromatic hydrocarbons such as benzene and toluene; aliphatic hydrocarbons such as pentane and hexane; alicyclic hydrocarbons such as cyclohexane and decalin; ethers such as tetrahydrofuran and ethylene glycol dimethyl ether.

The inert organic solvent may be the same as or different from the solvent used in the ring-opening polymerization reaction. Further, a hydrogenation catalyst may be added directly to the ring-opening polymerization reaction liquid to carry out the hydrogenation reaction.

The reaction conditions for the hydrogenation reaction vary depending on the hydrogenation catalyst used, and the reaction temperature is preferably-20 ℃ or higher, more preferably-10 ℃ or higher, particularly preferably 0 ℃ or higher, preferably +250 ℃ or lower, more preferably +220 ℃ or lower, and particularly preferably +200 ℃ or lower. When the reaction temperature is too low, the reaction rate becomes too slow, and when the reaction temperature is too high, side reactions occur.

The hydrogen pressure is preferably 0.01MPa or more, more preferably 0.05MPa or more, particularly preferably 0.1MPa or more, and further preferably 20MPa or less, more preferably 15MPa or less, particularly preferably 10MPa or less. When the hydrogen pressure is too low, the reaction rate may become too slow, and when the hydrogen pressure is too high, a special apparatus such as a high-pressure resistant reaction apparatus is required.

The reaction time is not particularly limited as long as a desired hydrogenation rate can be achieved, and is usually 0.1 hour or more and 10 hours or less.

After the hydrogenation reaction, the objective polymer (. alpha.1) is recovered by a conventional method. Further, the recovered polymer (. alpha.1) may be dried by a conventional method.

The hydrogenation rate (the proportion of unsaturated bonds to be hydrogenated) in the hydrogenation reaction is not particularly limited, but is preferably 98% or more, more preferably 99% or more, and the higher the hydrogenation rate is, the better the heat resistance of the polymer (α 1) is¹H-NMR was measured.

In the present invention, the polymer (α) may be used alone in 1 kind or in combination of 2 or more kinds.

< fibers >

The fibers are not particularly limited as long as they contain the crystalline alicyclic structure-containing resin, but preferably contain 50 mass% or more of the crystalline alicyclic structure-containing resin, and more preferably contain 100 mass% of the crystalline alicyclic structure-containing resin, that is, are formed only of the crystalline alicyclic structure-containing resin.

[ number average fiber diameter ]

The number average fiber diameter is not particularly limited, but is preferably 1nm or more, more preferably 5nm or more, particularly preferably 10nm or more, and further preferably 10 μm or less, more preferably 7 μm or less, and particularly preferably 5 μm or less.

By using a nonwoven fabric formed of fibers having a number average fiber diameter of not less than the lower limit, workability can be improved. Further, by using a nonwoven fabric formed of fibers having a number average fiber diameter of not more than the above upper limit value, a filter having a high collection rate can be produced.

The "number average fiber diameter" can be measured by the method described in the examples of the present specification.

The "pore size of the nonwoven fabric", "surface area of the nonwoven fabric" and "air permeability of the nonwoven fabric" will be described in detail below.

< pore size of nonwoven Fabric >

The pore diameter of the nonwoven fabric is not particularly limited as long as it is 5 μm or less, but is preferably 0.1 μm or more, more preferably 0.5 μm or more, and particularly preferably 0.8 μm or more, and is preferably 4.9 μm or less, more preferably 4.8 μm or less, and particularly preferably 4.7 μm or less.

By using a nonwoven fabric having a pore diameter of not less than the lower limit, a filter having a small pressure loss can be produced. Further, by using a nonwoven fabric having a pore size of not more than the above upper limit value, a filter having a high collection rate can be produced.

Here, the "pore diameter of the nonwoven fabric" means "pore diameter measured by the bubble point method", and means that the nonwoven fabric is immersed in a liquid (for example, isopropyl alcohol) to increase the gas pressure, bubbles are first generated from pores having the largest pore diameter, and the maximum pore diameter D calculated by using the following formula (1) is calculated based on the pressure (bubble point pressure) at the time of generation of the bubbles_BP(μm)。

D_BP＝(4γcosθ/P)×10^-6……(1)

In formula (1), γ represents the surface tension (N/m) of the liquid, θ represents the contact angle (rad) of the liquid with the nonwoven fabric, and P represents the bubble point pressure (Pa).

< surface area of nonwoven Fabric >

The surface area of the nonwoven fabric is not particularly limited, but is preferably 0.5mm²A value of at least g, more preferably 0.7mm²A specific range of 0.9mm or more in terms of/g²A thickness of 20mm or more²A value of not more than g, more preferably 15mm²A specific value of 12mm or less per gram²The ratio of the carbon atoms to the carbon atoms is less than g.

By using a nonwoven fabric having a surface area of not less than the lower limit, a filter having a high collection rate can be produced. Furthermore, the use of a nonwoven fabric having a surface area of not more than the above upper limit can improve workability.

The "surface area of the nonwoven fabric" refers to "surface area per 1g of nonwoven fabric", and can be measured by using a specific surface area measuring apparatus (MONOSORB, Quantachrome).

In the filter having the nonwoven fabric, when the pore diameter of the nonwoven fabric is increased, the surface area of the nonwoven fabric tends to be decreased, and when the surface area of the nonwoven fabric is excessively decreased, the load applied when the liquid starts to flow is increased, and the fibers in the nonwoven fabric are damaged, so that it is necessary to replace the nonwoven fabric in the filter at an early stage. However, if the surface area of the nonwoven fabric is within the above-described preferred range, it is possible to suppress the nonwoven fabric of the filter from being replaced in advance.

< air permeability of nonwoven Fabric >

The air permeability of the nonwoven fabric is not particularly limited, but is preferably 1.0(s (sec)/1000 mL) or more, more preferably 2.0(s/1000mL) or more, and particularly preferably 3.0(s/1000mL) or more.

By using a nonwoven fabric having an air permeability of not less than the lower limit, a filter having a high collection rate can be produced.

The "air permeability of the nonwoven fabric" can be measured by the method described in the examples of the present specification.

(Filter)

The filter of the present invention includes the nonwoven fabric of the present invention, and examples thereof include a filter in which a nonwoven fabric processed into a pleated shape is stored in a cartridge by a known method described in jp 60-58208 a.

< pleating >

The number of folds of the wrinkles is not particularly limited, but is preferably 10 or more, and further preferably 1000 or less.

By appropriately adjusting the number of folds of the wrinkles, (i) the ease of storage in the cartridge, (ii) the contact area between the nonwoven fabric and the liquid, and the like can be adjusted.

< Cartridge >

The cartridge is not particularly limited, and examples thereof include known cartridges described in Japanese patent application laid-open No. 60-58208.

Hereinafter, the "collection rate of the filter", "pressure loss of the filter", and "time required for replacing the nonwoven fabric in the filter" will be described in detail.

< Collection Rate >

The collection rate of the filter is not particularly limited, but is preferably 95% or more, more preferably 96% or more, particularly preferably 97% or more, and most preferably 100%.

By using a nonwoven fabric having a collection rate of not less than the lower limit, particles can be collected efficiently.

The "collection rate" can be measured by the method described in the examples of the present specification.

< pressure loss >

The pressure loss of the filter is not particularly limited, but is preferably 10kPa or less, more preferably 9.8kPa or less, particularly preferably 9.6kPa or less, and most preferably 0 kPa.

By using a nonwoven fabric having a pressure loss of the upper limit value or less, clogging of the nonwoven fabric can be suppressed.

The "pressure loss" can be measured by the method described in the examples of the present specification.

< time required for replacement >

The time required for replacing the nonwoven fabric in the filter is not particularly limited, but is preferably 200 minutes or longer, more preferably 240 minutes or longer, and particularly preferably 260 minutes or longer.

By using a nonwoven fabric whose replacement time is equal to or longer than the lower limit value, clogging of the nonwoven fabric can be suppressed, and particles can be collected efficiently.

The "replacement required time" can be measured by the method described in the examples of the present specification.

Further, the filter of the present invention can be preferably used as a filter for manufacturing a semiconductor element used in manufacturing a semiconductor element such as a semiconductor chip.

< Filter for manufacturing semiconductor device >

The filter for manufacturing a semiconductor device is used, for example, for removing particles (particles) as impurities in a chemical liquid or the like used in manufacturing a semiconductor device such as a semiconductor chip.

Here, the particle diameter of fine particles (particles) as impurities contained in a chemical solution or the like used in a semiconductor manufacturing process is usually 100nm or less, and when they are aggregated to form secondary particles, the particle diameter becomes about 1 μm. Here, if a filter having the nonwoven fabric of the present invention (pore diameter measured by bubble point method: 5 μm or less) is used, the secondary particles having a particle diameter of about 1 μm can be collected.