JP2006009167A - Fibrous foam and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for assortedly and easily producing fine fibrous foams having fine closed cells and open cells imparting high functionality, without any complicated production steps including waste liquor recovery/recycling steps, enabling materials to be relatively freely chosen as desired, and seldom causing yarn breakages and the like. <P>SOLUTION: The method for producing fibrous foams comprises forming a foamable composition into filaments, irradiating them with active energy rays followed by heating and foaming. In this method, the foamable composition comprises an acid generator or base generator that generates an acid or base by the action of active energy rays and a compound having such a split-foamable functional group as to split-eliminate one or more low-boiling volatile substances on reacting with an acid or base. The fibrous foams thus obtained are also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a fibrous foam and a method for producing the same. In the present invention, the foam refers to those having a plurality of independent bubbles and / or a plurality of continuous bubbles, or both. In particular, those having open cells may be called porous bodies. In the present invention, the fibrous form means a fine solid composed of long fibers (filaments), short fibers (staples), fibers and the like, and includes simple fibers such as hollow fibers, composite fibers, and irregular cross-section fibers. Fiber is also included. In addition, it also refers to processed yarns such as spun yarns obtained by twisting them together, mixed yarns and twisted yarns, entangled yarns and crimped yarns having various forms. In addition, various finished products such as woven and knitted fabrics, non-woven fabrics, paper, artificial leather, filling materials, woven fabrics, knitted fabrics, fiber laminates, and clothing, living materials, industrial materials, medical supplies, electrical and electronic components, etc. Is also included. There are no restrictions on the fineness or length.
The fibrous foam of the present invention has color developability, bulkiness, dryness, swelling, softness, breathability, heat insulation, low dielectric constant, light scattering, light reflectivity, hiding, whiteness, and opaqueness. , Wavelength selective reflection and transmission, lightness, levitation, sound insulation, sound absorption, shock absorption, cushioning, absorption, adsorption, storage, transmission, filterability, etc. It is useful as a fibrous foam.

  In recent years, high functionalization is demanded in the textile field as well as high functionalization of materials in various fields. Higher functionality from the structural side of the fiber includes compounding, miniaturization, and irregular cross-section. In addition to this, high functionality is also achieved by foaming and porosity. It is impossible to make a foam thinner than the size of the bubbles, and in order to obtain a thin foam called a fibrous foam, it is necessary to reduce the bubble diameter. In the foam, generally, bubbles become an internal defect of the material. Therefore, when foamed, the mechanical strength of the material is lowered. However, it is said that the strength reduction can be suppressed by making the bubbles finer.

  In general, an extraction method or a stretching method is used in the manufacturing process of a thin fibrous foam having a small bubble diameter. In the extraction method, a spinning stock solution consisting of an elution material soluble in a solvent and a base material that is insoluble or hardly soluble in the solvent is spun and then only the elution material is eluted from the base material with the solvent to create a void. After spinning a spinning stock solution consisting of a non-eluting material that is insoluble or difficult to dissolve in a solvent and a base material that is soluble in the solvent, the base material surface is eluted with a solvent, and the non-eluting material flows out and the portion becomes a void. There is a way to do it. Elution materials include water-soluble elution materials such as sodium chloride, sodium sulfate, glucose, sucrose, starch, PVA, and polyalkylene glycol, alkali-soluble elution materials such as polyester copolymerized with polylactic acid and organic sulfonic acid, and organic solvent solubility. General organic matter of the above. Examples of the method of eluting the surface of the base material include alkali reduction treatment of polyester containing inorganic fine particles as a non-eluting material. References for extraction methods include Patent Documents 1-3.

  The stretching method includes blending incompatible components (polymer, inorganic particles, etc.) into the base material, stretching after molding, and peeling and opening the incompatible component / base material interface, and thermoplastic crystalline polymer. There are a method of peeling and opening a crystal interface formed by melt spinning and then stretching, and a method of stretching a yarn composed of a plurality of polymers having different extensional viscosities to create an opening in a high extensional viscosity polymer part. (Patent Documents 4 to 6)

  Thus, although it is the extraction method and the extending | stretching method said to be suitable for manufacture of a fibrous fine foam, there exist the following concerns. In the extraction method, a process for removing the solvent, a process for separating and removing the eluent and the base material when the solvent is reused, and a special waste liquid recovery process are also required. There are still major challenges from an environmental point of view. In the stretching method, the process is simple. However, in the case of a stretching method in which an incompatible component is added, if an incompatible component that is a foreign substance enters, yarn breakage is likely to occur during production. In the case of a crystalline polymer stretching method, There are concerns that the base polymer is limited to those having crystallinity, so the degree of freedom in material selection is small, and it is difficult to perform detailed control of the foam structure such as the bubble diameter and foaming ratio by the stretching method using the difference in elongational viscosity. is there. In general, it is easy to obtain a porous material by the extraction method and the stretching method, but there are many restrictions such as relatively difficult to produce closed cells.

  Another method for producing a fibrous foam is a foaming method, which is exemplified in Patent Documents 7 to 10 and the like. In the foaming method, a foaming agent that generates gas when stimulated by heat or light is added to the spinning raw material, and after spinning by methods such as melt spinning and solution spinning, it is foamed by heat or light, or foamed simultaneously with spinning. Is the method. Compared with the extraction method, the process is not complicated, and various types of base polymer can be used as compared with the stretching method. Further, in the foaming method, closed cells are basically formed, and if necessary, after being foamed, holes can be opened by stretching or the like, so that both closed cells and open cells can be formed relatively easily.

There are two types of foaming agents: chemical foaming agents and physical foaming agents. Chemical foaming agents include thermal decomposition type and photodecomposition type. The pyrolytic foaming agent is thermally decomposed to release one or more kinds of gases such as nitrogen and carbon dioxide. Organic compounds such as azo compounds represented by azodicarbonamide and azobisisobutyronitrile, sulfonyl hydrazide compounds represented by p, p'-oxybisbenzenesulfonyl hydrazide, and inorganic compounds such as sodium bicarbonate It has been known. The foaming method using a thermally decomposable foaming agent is a method of kneading or dissolving in a polymer softened in a temperature range below the decomposition temperature of the foaming agent and then heating to a temperature range above the decomposition temperature of the foaming agent. It has been put into practical use. If necessary, a foaming auxiliary agent, a crosslinking agent, a stabilizer and the like are used in combination. The photodecomposable foaming agent is decomposed by active energy rays such as ultraviolet rays and electron beams to release a gas such as nitrogen. Examples thereof include compounds having an azide group such as p-azidobenzaldehyde and compounds having a diazo group such as p-diazodiphenylamine. The foaming method using a photolytic foaming agent is foaming by irradiation with energy rays or foaming by heating after irradiation. In general, an organic compound that generates gas in the course of polymer polymerization is also included in the chemical foaming agent, and typical examples thereof include polyurethane. Polyurethane is a polymer of a polyol (an oligomer having at least two —OH groups which are alcoholic hydroxyl groups) and a polyisocyanate (having two or more —NCO groups which are isocyanate groups in the molecule). In the process, CO ₂ gas is generated to form a foam.

  Examples of the physical blowing agent include low boiling point volatile substances such as volatile saturated hydrocarbon substances represented by butane and pentane, and volatile fluorinated hydrocarbon substances represented by fluoroethane. . As physical foaming agents, low-boiling volatile substances that are liquid at normal temperature but volatilize at 50 to 100 ° C. and become gases are often used, and these are contained in polymer materials at temperatures below the boiling point. A foam can be formed by impregnating and heating it above the boiling point of the physical blowing agent. Also, an inert gas that is in a gaseous state at normal temperature and pressure, such as carbon dioxide and nitrogen, can be used as a physical foaming agent. In this case, an inert gas in a gaseous state is dissolved in a polymer material in a molten state controlled to an appropriate pressure and temperature, and then this mixed system is released to a normal temperature and normal pressure state, thereby obtaining a liquid. The phase substance rapidly vaporizes and expands to obtain a foam. As another foaming agent, a capsule-like foaming agent produced by sealing a low-boiling volatile substance in a thermoplastic polymer material as an outer shell is also known.

  As a special foaming method, there is a method of obtaining a fine fiber nonwoven fabric (microporous film) by opening by foaming / breaking, such as a burst fiber method or a flash spinning method. In the burst fiber method, as shown in Patent Documents 11 to 12, etc., bubbles are generated by foaming in a film-shaped molded article, and then the bubbles are broken and opened by stretching the film-shaped molded article. This is a method for producing a net-like body, that is, a nonwoven fabric. In the flash spinning method, as shown in Patent Document 13 or the like, a polymer fiber is dissolved in a low boiling point solvent, heated and pressurized, sprayed from a nozzle, and the solvent is instantly vaporized to obtain a mesh fiber. It can be done. However, the fiber diameter varies relatively.

  As described above, various methods have been studied in the foaming method, but the foaming method has a fundamental weakness. That is, the bubble diameter obtained is large and it is difficult to optimize the bubble diameter. As a result, yarn breakage was likely to occur during production, and the strength of the product was low. In order to overcome this, it is necessary to reduce the bubble diameter, but in order to do so, a large amount of foaming agent has to be added, which results in the contradiction that spinnability and fiber properties are sacrificed.

In recent years, as a foam having a small cell diameter, a material called microcellular plastic characterized by a cell diameter of 0.1 to 10 μm and a cell density of 10 ⁹ to 10 ¹⁵ pieces / cm ³ has been developed by N. Massachusetts Institute of Technology. Proposed by P. Suh et al. (For example, patent document 14).
This microcellular plastic is obtained by impregnating and saturated an inert gas such as carbon dioxide and nitrogen as a physical foaming agent in a high pressure or supercritical state, and then reducing the pressure and heating. In this method, the larger the impregnation amount of the inert gas, the smaller the bubble diameter and the higher the bubble density. Therefore, a high saturation impregnation amount is obtained by high pressure impregnation, but there is a problem that it takes a long time to reach saturation. For example, it has been reported that several days are required to impregnate and saturate carbon dioxide in polyethylene terephthalate, and the poor production efficiency is a problem. In order to shorten the impregnation time of the inert gas, there is a dilemma based on the basic principle that if a material that is easily impregnated is used, the following outgassing phenomenon is likely to occur. The outgassing phenomenon is a phenomenon in which a part of the gas impregnated in a high pressure state is diffused from the plastic surface before foaming in the decompression process. Since the saturated concentration of impregnation of the inert gas into the plastic is as small as about 10 wt%, it is strongly affected by outgassing from the surface. In particular, in the case of thin and thin objects such as fibers and films, the influence appears remarkably, so it was difficult to obtain a foam. It was not easy to obtain a fibrous foam having micron-order and sub-micron-order bubbles with a fine fiber having a fineness of several tens of dtex (thickness of several tens of μm) indicating the thickness of the fiber. Therefore, it has been extremely difficult to apply this method to the production of a fibrous foam having microbubbles.

By the way, when the foam is made of a polymer material having high hygroscopicity and water absorption, if the foam is left in a high humidity environment, the foam gradually permeates and adsorbs moisture, and becomes soft. Dimensional change (expansion or contraction) of foam and loss of foam structure (porous structure) are likely to occur. Such foams have insufficient foaming characteristics, so that the use environment conditions are restricted, and the application development is difficult. Therefore, it is important to improve the water- and moisture-resistant storage stability of the foam, and many such solutions have been reported. As a report example, there is a method (physical hydrophobization treatment method) in which water resistance is improved by spraying and adsorbing hydrophobic fine particles on the foam surface (for example, Patent Document 15). In addition, there is a chemical method (chemical hydrophobization treatment method) in which moisture resistance is improved by reacting an airgel that is a hydrophilic porous body with a compound having a hydrophobic functional group (for example, Patent Document 16). ).
JP 2003-105627 A, Gazette JP 2003-73924 A JP-A-11-222725 Japanese Patent Laid-Open No. 7-213876 Japanese Patent No. 3216221 JP 2001-172836 A Publication 2003-129342 Japanese Patent Laid-Open No. 2000-220027 JP-A-10-183425 JP-A-8-17257 Japanese Patent No. 3311383 Japanese Patent Laid-Open No. 51-47170 Special table 2000-503731 U.S. Pat. No. 4,473,665 JP 2001-92467 A JP 2000-264620 A JP-A-8-248561 JP 2000-330270 A JP-A-9-102230 "Foam / Porous Material Technology and Application Development" (Toray Research Center, 1996) “Development of new microporous film membrane products” (Osaka Chemical Marketing Center, 2001) K. Ichimura et al., Chemistry Letters, 551-552 (1995).

  The problem to be solved by the present invention is that there is no complicated manufacturing process such as waste liquid recovery / regeneration process, materials can be selected relatively freely, and there are fine independent and continuous bubbles that are less likely to cause yarn breakage etc. It is to provide a fibrous foam production method capable of producing a fibrous foam, and to easily obtain a thin fibrous foam having fine bubbles capable of imparting high functionality.

  In order to solve the above problems, the present invention adopts the following configuration. That is, the first of the present invention includes "an acid generator that generates an acid by the action of active energy rays or a base generator that generates a base, and further reacts with an acid or a base to produce one or more low boiling points. A fibrous foam produced from a foamable composition containing a compound having a decomposable foamable functional group that decomposes and desorbs volatile substances.

  The second aspect of the present invention includes "an acid generator that generates an acid by the action of active energy rays or a base generator that generates a base, and further reacts with an acid or a base to produce one or more low boiling point volatility. Production of a fibrous foam characterized by forming a foamable composition containing a compound having a decomposable foamable functional group capable of decomposing and desorbing a substance into a fibrous form, followed by foaming by irradiation with active energy rays Method.

  According to a third aspect of the present invention, there is provided the method for producing a fibrous foam according to the second aspect, wherein the foam is formed by heating after irradiation with active energy rays.

  According to the present invention, a fiber having fine independent and continuous bubbles that does not have a complicated manufacturing process that causes cost and environmental load such as a waste liquid recovery / regeneration process, can select materials relatively freely, and is less susceptible to yarn breakage. Provided is a method for producing a fibrous foam capable of easily producing a foam-like foam, and a thin fibrous foam having fine bubbles capable of imparting high functionality can be easily obtained.

  The foamable composition used in the present invention is a composition comprising at least the following two components. One of them is an acid generator that generates an acid by the action of an active energy ray, or a base generator that generates a base, and the other is one or more types that react with the generated acid or base. It is a decomposition foamable compound that decomposes and desorbs low boiling point volatile compounds.

Acid generator, base generator The acid generator or base generator used in the foamable composition used in the present invention is a photo-acid generator used for chemically amplified photoresists and photocationic polymerization. Or what is called a photobase generator can be used.

As a photoacid generator suitable for the present invention,
(1) Diazonium salt compounds (2) Ammonium salt compounds (3) Iodonium salt compounds (4) Sulfonium salt compounds (5) Oxonium salt compounds (6) Phosphonium salt compounds Mention may be made of PF _6- , AsF _6- , SbF ₆ -and CF ₃ SO ₃ -salts of aliphatic onium compounds. Although the specific example is enumerated below, it is not limited to what was illustrated.

Bis (phenylsulfonyl) diazomethane,
Bis (cyclohexylsulfonyl) diazomethane,
Bis (tert-butylsulfonyl) diazomethane,
Bis (p-methylphenylsulfonyl) diazomethane,
Bis (4-chlorophenylsulfonyl) diazomethane,
Bis (p-tolylsulfonyl) diazomethane,
Bis (4-tert-butylphenylsulfonyl) diazomethane,
Bis (2,4-xylylsulfonyl) diazomethane,
Bis (cyclohexylsulfonyl) diazomethane,
Benzoylphenylsulfonyldiazomethane,

Trifluoromethanesulfonate,
Trimethylsulfonium trifluoromethanesulfonate,
Triphenylsulfonium trifluoromethanesulfonate,
Triphenylsulfonium hexafluoroantimonate,
2,4,6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate, p-tolyldiphenylsulfonium trifluoromethanesulfonate,
4-phenylthiophenyldiphenylsulfonium hexafluorophosphate,
4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate,
1- (2-naphthoylmethyl) thiolanium hexafluoroantimonate,
1- (2-naphthoylmethyl) thiolanium trifluoromethanesulfonate,
4-hydroxy-1-naphthyldimethylsulfonium hexafluoroantimonate,
4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate,
(2-oxo-1-cyclohexyl) (cyclohexyl) methylsulfonium trifluoromethanesulfonate,
(2-oxo-1-cyclohexyl) (2-norbornyl) methylsulfonium trifluoromethanesulfonate,
Diphenyl-4-methylphenylsulfonium perfluoromethanesulfonate,
Diphenyl-4-tert-butylphenylsulfonium perfluorooctanesulfonate,
Diphenyl-4-methoxyphenylsulfonium perfluorobutanesulfonate,

Diphenyl-4-methylphenylsulfonium tosylate,
Diphenyl-4-methoxyphenylsulfonium tosylate,
Diphenyl-4-isopropylphenylsulfonium tosylate

Diphenyliodonium,
Diphenyliodonium tosylate,
Diphenyliodonium chloride,
Diphenyliodonium hexafluoroarsenate,
Diphenyliodonium hexafluorophosphate,
Diphenyliodonium nitrate,
Diphenyliodonium perchlorate,
Diphenyliodonium trifluoromethanesulfonate,

Bis (methylphenyl) iodonium trifluoromethanesulfonate,
Bis (methylphenyl) iodonium tetrafluoroborate,
Bis (methylphenyl) iodonium hexafluorophosphate,
Bis (methylphenyl) iodonium hexafluoroantimonate,
Bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate,
Bis (4-tert-butylphenyl) iodonium hexafluorophosphate,
Bis (4-tert-butylphenyl) iodonium hexafluoroantimonate,
Bis (4-tert-butylphenyl) iodonium perfluorobutanesulfonate,

2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine,
2,4,6-tri (trichloromethyl) -1,3,5-triazine,
2-phenyl-4,6-ditrichloromethyl-1,3,5-triazine,
2- (p-methoxyphenyl) -4,6-ditrichloromethyl-1,3,5-triazine,
2-naphthyl-4,6-ditrichloromethyl-1,3,5-triazine,
2-biphenyl-4,6-ditrichloromethyl-1,3,5-triazine,
2- (4′-hydroxy-4-biphenyl) -4,6-ditrichloromethyl-1,3,5-triazine,
2- (4′-methyl-4-biphenyl) -4,6-ditrichloromethyl-1,3,5-triazine,
2- (p-methoxyphenylvinyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-chlorophenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-methoxy-1-naphthyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (benzo [d] [1,3] dioxolan-5-yl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (3,4,5-trimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (3,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (2,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (2-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-butoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-pentyloxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,

2,6-di-tert-butyl-4-methylpyrylium trifluoromethanesulfonate,
Trimethyloxynium tetrafluoroborate,
Triethyloxynium tetrafluoroborate,
N-hydroxyphthalimide trifluoromethanesulfonate,
N-hydroxynaphthalimide trifluoromethanesulfonate,
(Α-benzoylbenzyl) p-toluenesulfonate,
(Β-benzoyl-β-hydroxyphenethyl) p-toluenesulfonate,
1,2,3-benzenetriyltrismethanesulfonate,
(2,6-dinitrobenzyl) p-toluenesulfonate,
(2-nitrobenzyl) p-toluenesulfonate,
(4-nitrobenzyl) p-toluenesulfonate,
Etc. Of these, iodonium salt compounds and sulfonium salt compounds are preferred.

In addition to the onium compounds, sulfonates that generate sulfonic acid upon irradiation with active energy rays, such as 2-phenylsulfonylacetophenone, halides that generate hydrogen halide upon irradiation with active energy rays, such as phenyltribromo. Methylsulfone and 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane, and ferrocenium compounds that generate phosphoric acid upon irradiation with active energy rays, such as bis (cyclopentadienyl) ferrocenium hexa Fluorophosphate, bis (benzyl) ferrocenium hexafluorophosphate, and the like can be used.
Furthermore, the following imide compound derivatives having acid generating ability can also be used.
N- (phenylsulfonyloxy) succinimide,
N- (trifluoromethylsulfonyloxy) succinimide,
N- (10-camphorsulfonyloxy) succinimide,
N- (trifluoromethylsulfonyloxy) phthalimide,
N- (trifluoromethylsulfonyloxy) -5-norbornene-2,3-dicarboximide,
N- (trifluoromethylsulfonyloxy) naphthalimide,
N- (10-camphorsulfonyloxy) naphthalimide.

As a photobase generator suitable for the present invention,
(1) Oxime ester compounds (2) Ammonium compounds (3) Benzoin compounds (4) Dimethoxybenzylurethane compounds (5) Orthonitrobenzylurethane compounds As an amine. In addition, a base generator that generates ammonia or hydroxy ions by the action of light may be used. These include, for example, N- (2-nitropentyloxycarbonyl) piperidine, 1,3-bis [N- (2-nitrobenzyloxycarbonyl) -4-piperidyl] propane, N, N′-bis (2-nitrobenzyl). It can be selected from oxycarbonyl) dihexylamine, O-benzylcarbonyl-N- (1-phenylethylidene) hydroxylamine, and the like. Further, a compound that generates a base by heating may be used in combination with the photobase generator.

  In order to expand the wavelength region of the active energy ray of the photoacid generator or photobase generator, a photosensitizer may be used in combination as appropriate. For example, examples of photosensitizers for onium salt compounds include acridine yellow, benzoflavin, and acridine orange.

  As a method of minimizing the addition amount of the acid generator or base generator and the light irradiation energy while generating the necessary acid, an acid proliferating agent or a base proliferating agent (see Non-patent Document 3 and Patent Documents 17 to 18). ) Can be used with an acid generator or a base generator. The acid proliferator is thermodynamically stable at around room temperature, but decomposes with acid and generates a strong acid by itself to greatly accelerate the acid-catalyzed reaction. By utilizing this reaction, it is possible to improve the generation efficiency of acid or base, and to control the foam generation rate and the foam structure.

Decomposable foamable compound The decomposable foamable compound (hereinafter abbreviated as a decomposable compound) used in the foamable composition used in the present invention reacts with an acid or a base to produce one or more low boiling volatile substances (low boiling point). Volatile compounds are decomposed and desorbed. That is, this decomposable compound must be previously introduced with a degradable functional group capable of generating a low boiling point volatile substance. The low boiling point volatile substance is a substance that is gasified at the time of foaming, and its boiling point is not more than the foaming heating temperature, usually not more than 100 ° C., preferably not more than room temperature. Examples of the low boiling point volatile substance include isobutene (boiling point −7 ° C.), carbon dioxide (boiling point −79 ° C.), nitrogen (boiling point −196 ° C.), and the like. Examples of the decomposable functional group include a moiety containing tert-butyl group, tert-butyloxycarbonyl group, keto acid and keto acid ester as one that reacts with an acid, and a urethane group or carbonate as one that reacts with a base. Groups and the like. It reacts with an acid, tert-butyl group is isobutene gas, tert-butyloxycarbonyl group is isobutene gas and carbon dioxide, keto acid site is carbon dioxide, keto acid ester such as tert-butyl keto acid is carbon dioxide. And isobutene. By reacting with the base, the urethane group and the carbonate group generate carbon dioxide gas. As examples of the acid (or base) decomposable compound, monomers, oligomers, polymer compounds (polymers) and the like can be used. For example, the compounds can be classified into the following compound groups.
(1) Non-curable low molecular weight degradable compound group (2) Curable monomer based degradable compound group (3) Polymeric degradable compound group Examples of curable monomer based degradable compounds In the case of an active energy ray-curable compound containing a vinyl group that causes a polymerization reaction when irradiated with active energy rays, it is easy to form uniform fine bubbles, and fibrous foam with excellent strength It is possible to get a body. Specific examples of the decomposable compound are shown below.

(1) -a, non-curing low molecular weight decomposable compound group <acid decomposable compound>
1-tert-butoxy-2-ethoxyethane,
2- (tert-butoxycarbonyloxy) naphthalene,
N- (tert-butoxycarbonyloxy) phthalimide,
2,2-bis [p- (tert-butoxycarbonyloxy) phenyl] propane, etc.

(1) -b, non-curing low molecular weight decomposable compound group <base decomposable compound>
N- (9-fluorenylmethoxycarbonyl) piperidine, etc.

(2) -a, curable monomer-based decomposable compound group <acid-decomposable compound>
tert-butyl acrylate,
tert-butyl methacrylate,
tert-butoxycarbonylmethyl acrylate,
2- (tert-butoxycarbonyl) ethyl acrylate,
p- (tert-butoxycarbonyl) phenyl acrylate,
p- (tert-butoxycarbonylethyl) phenyl acrylate,
1- (tert-butoxycarbonylmethyl) cyclohexyl acrylate,
4-tert-butoxycarbonyl-8-vinylcarbonyloxy-tricyclo [5.2.1.02,6] decane,
2- (tert-butoxycarbonyloxy) ethyl acrylate,
p- (tert-butoxycarbonyloxy) phenyl acrylate,
p- (tert-butoxycarbonyloxy) benzyl acrylate,
2- (tert-butoxycarbonylamino) ethyl acrylate,
6- (tert-butoxycarbonylamino) hexyl acrylate,
p- (tert-butoxycarbonylamino) phenyl acrylate,
p- (tert-butoxycarbonylamino) benzyl acrylate,
p- (tert-butoxycarbonylaminomethyl) benzyl acrylate,
(2-tert-butoxyethyl) acrylate,
(3-tert-butoxypropyl) acrylate,
(1-tert-butyldioxy-1-methyl) ethyl acrylate,
3,3-bis (tert-butyloxycarbonyl) propyl acrylate,
4,4-bis (tert-butyloxycarbonyl) butyl acrylate,
p- (tert-butoxy) styrene,
m- (tert-butoxy) styrene,
p- (tert-butoxycarbonyloxy) styrene,
m- (tert-butoxycarbonyloxy) styrene,
Acryloyl acetate, methacryloyl acetate tert-butyl acryloyl acetate
N- (tert-butoxycarbonyloxy) maleimide such as tert-butylmethacloyl acetate

(2) -b, curable monomer group decomposable compound group <base decomposable compound>
4-[(1,1-dimethyl-2-cyano) ethoxycarbonyloxy] styrene,
4-[(1,1-dimethyl-2-phenylsulfonyl) ethoxycarbonyloxy] styrene,
4-[(1,1-dimethyl-2-methoxycarbonyl) ethoxycarbonyloxy] styrene,
4- (2-cyanoethoxycarbonyloxy) styrene,
(1,1-dimethyl-2-phenylsulfonyl) ethyl methacrylate,
(1,1-dimethyl-2-cyano) ethyl methacrylate, etc.

(3) -a, decomposable compound group of polymer system <acid-decomposable compound>
Poly (tert-butyl acrylate),
Poly (tert-butyl methacrylate),
Poly (tert-butoxycarbonylmethyl acrylate),
Poly [2- (tert-butoxycarbonyl) ethyl acrylate],
Poly [p- (tert-butoxycarbonyl) phenyl acrylate],
Poly [p- (tert-butoxycarbonylethyl) phenyl acrylate],
Poly [1- (tert-butoxycarbonylmethyl) cyclohexyl acrylate],
Poly {4-tert-butoxycarbonyl-8-vinylcarbonyloxy-tricyclo [5.2.1.02,6] decane},
Poly [2- (tert-butoxycarbonyloxy) ethyl acrylate],
Poly [p- (tert-butoxycarbonyloxy) phenyl acrylate],
Poly [p- (tert-butoxycarbonyloxy) benzyl acrylate],
Poly [2- (tert-butoxycarbonylamino) ethyl acrylate],
Poly [6- (tert-butoxycarbonylamino) hexyl acrylate],
Poly [p- (tert-butoxycarbonylamino) phenyl acrylate],
Poly [p- (tert-butoxycarbonylamino) benzyl acrylate],
Poly [p- (tert-butoxycarbonylaminomethyl) benzyl acrylate],
Poly (2-tert-butoxyethyl acrylate),
Poly (3-tert-butoxypropyl acrylate),
Poly [(1-tert-butyldioxy-1-methyl) ethyl acrylate],
Poly [3,3-bis (tert-butyloxycarbonyl) propyl acrylate],
Poly [4,4-bis (tert-butyloxycarbonyl) butyl acrylate],
Poly [p- (tert-butoxy) styrene],
Poly [m- (tert-butoxy) styrene],
Poly [p- (tert-butoxycarbonyloxy) styrene],
Poly [m- (tert-butoxycarbonyloxy) styrene],
Polyacryloyl acetic acid, polymethacryloyl acetic acid,
Poly [tert-butyl acroyl acetate],
Poly [tert-butyl methacryloyl acetate]
N- (tert-butoxycarbonyloxy) maleimide / styrene copolymer, etc.

(3) -b, decomposable compound group of polymer system <base decomposable compound>
Poly {p-[(1,1-dimethyl-2-cyano) ethoxycarbonyloxy] styrene},
Poly {p-[(1,1-dimethyl-2-phenylsulfonyl) ethoxycarbonyloxy] styrene},
Poly {p-[(1,1-dimethyl-2-methoxycarbonyl) ethoxycarbonyloxy] styrene},
Poly [p- (2-cyanoethoxycarbonyloxy) styrene],
Poly [(1,1-dimethyl-2-phenylsulfonyl) ethyl methacrylate],
Poly [1,1-dimethyl-2-cyano) ethyl methacrylate],
And so on.
Organic polymer compounds such as polyethers, polyamides, polyesters, polyimides, polyvinyl alcohols and dendrimers into which degradable functional groups are introduced can be used as acid-decomposable or base-decomposable polymer compounds. Furthermore, an acid-decomposable or base-decomposable polymer compound in which a decomposable functional group is introduced into an inorganic compound such as silica is also included. Especially, it is preferable that a decomposable functional group is introduce | transduced into the compound group which has a functional group chosen from the group which consists of a carboxylic acid group or a hydroxyl group, and an amine group.

The decomposable compound group may be used alone or in combination of two or more different types. Moreover, the decomposable compound can be used by mixing with other resins. When mixed, the decomposable compound and the other resin may be either compatible or incompatible. Other resins include polyester resins such as polyethylene terephthalate and polybutylene terephthalate, unsaturated polyester resins, polycarbonate resins, polyolefin resins such as polyethylene and polypropylene, polyolefin composite resins, polystyrene resins, polybutadiene resins, (meth) acrylic resins, Acryloyl resin, ABS resin, fluororesin, polyimide resin, polyacetal resin, polysulfone resin, vinyl chloride resin, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, starch, polyvinyl alcohol, polyamide resin, phenol resin, melamine resin, urea resin, urethane resin, It can be appropriately selected from commonly used resins such as epoxy resins and silicone resins. Moreover, a gas barrier resin can also be used for the purpose of incorporating in the fiber a low boiling point volatile substance that decomposes and gasifies from the decomposable compound. The gas barrier resin may be mixed or laminated, and is preferably laminated on the surface of the fiber in order to make the low boiling point volatile substance in the fiber.
Among the decomposable foaming compounds, the curable monomer-based decomposable compound group and the polymer-based decomposable compound group may be used singly or in combination with the generally used resins. On the other hand, since the non-curable low molecular weight decomposable compound group cannot be molded alone, it is necessary to use it by mixing with the generally used resin.

In order to increase the water resistance of the fibrous foam of the present invention, a compound obtained by introducing a decomposable foamable functional group into a compound containing at least one hydrophobic functional group can also be used as the foamable composition. The hydrophobic functional group used in the present invention is preferably selected from the group consisting mainly of an aliphatic group, an alicyclic group, an aromatic group, a halogen group, and a nitrile group. The decomposable and foamable functional group is easily introduced into a hydrophilic functional group selected from the group consisting mainly of a carboxylic acid group, a hydroxyl group and an amine group. Therefore, the decomposable compound of the present invention is preferably a composite compound comprising a decomposable unit in which a decomposable and foamable functional group is introduced into the hydrophilic functional group and a hydrophobic unit containing a hydrophobic functional group. In the more preferable composite compound, the decomposable unit and the hydrophobic unit are vinyl polymers. Hydrophobic units include aliphatic (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate, aromatic vinyl compounds such as styrene, methylstyrene and vinylnaphthalene, (meth) acrylonitrile compounds, vinyl acetate A compound group, a vinyl chloride compound group, etc. are mentioned. As a representative example of the decomposable compound, the decomposable unit is tert-butyl acrylate in which a tert-butyl group which is a decomposable functional group is introduced into acrylic acid having a carboxylic acid group of a hydrophilic functional group, and Examples thereof include vinyl copolymers comprising a combination in which the hydrophobic unit is methyl acrylate having a hydrophobic functional group methyl group. Specific examples of the decomposable compound comprising a combination of degradable unit / hydrophobic unit are shown below.
tert-butyl acrylate / methyl methacrylate copolymer tert-butyl methacrylate / methyl acrylate copolymer tert-butyl methacrylate / methyl methacrylate copolymer tert-butyl acrylate / ethyl acrylate copolymer tert-butyl acrylate / ethyl methacrylate copolymer Tert-butyl methacrylate / ethyl acrylate copolymer tert-butyl methacrylate / ethyl methacrylate copolymer tert-butyl acrylate / styrene copolymer tert-butyl acrylate / vinyl chloride copolymer tert-butyl acrylate / acrylonitrile copolymer p -(Tert-Butoxycarbonyloxy) styrene / styrene copolymer In addition, a degradable unit in the decomposable compound and The hydrophobic unit can be used alone or in combination of two or more. The form of copolymerization can be performed arbitrarily such as random copolymerization, block copolymerization, and graft copolymerization. In addition, the copolymerization ratio of the hydrophobic unit is preferably 5 to 95% by mass with respect to the total amount of the decomposable compound, and considering the decomposable foamability of the decomposable compound and the environmental preservation of the foamed structure, 20 to 80%. The mass% is more preferable.
The decomposable compounds may be used alone or in combination of two or more different types. The decomposable compound is a compound containing at least one or more kinds of hydrophobic functional groups after the decomposable and foamable functional groups are decomposed and released to generate a bubble forming gas.

  In order to increase the water resistance of the fibrous foam of the present invention, as the foamable composition, the equilibrium water absorption measured by the JIS K-7209D method in an environmental atmosphere at a temperature of 30 ° C. and a relative humidity of 60% is less than 10%. It is also possible to use a compound in which a decomposable and foamable functional group is introduced into this hygroscopic compound. Examples of the low hygroscopic compound having a structure in which a decomposable and foamable functional group can be easily introduced include p-hydroxystyrene and m-hydroxystyrene. Accordingly, examples of the decomposable compound include p- (tert-butoxy) styrene, m- (tert-butoxy) styrene, p- (tert-butoxycarbonyloxy) styrene, and m- (tert-butoxycarbonyloxy) styrene. These may be a curable monomer or a polymer in which one or more kinds are mixed.

Further, a decomposable and foamable functional group may be introduced into a composite compound comprising a combination of a highly hygroscopic compound having a water absorption rate of 10% or more and a low hygroscopic compound having a water absorption rate of less than 10%. However, the composite compound preferably has a water absorption of less than 10% by an appropriate combination. For example, a copolymer (composite compound) of acrylic acid, which is a highly hygroscopic compound, and p-hydroxystyrene, which is a low hygroscopic compound, has a copolymerization ratio of acrylic acid / p-hydroxystyrene = 90 / 10-0 / 100 is preferred. Specific examples of degradable compounds include
tert-butyl acrylate / p- (tert-butoxy) styrene copolymer tert-butyl acrylate / m- (tert-butoxy) styrene copolymer tert-butyl acrylate / p- (tert-butoxycarbonyloxy) styrene copolymer tert-butyl acrylate / m- (tert-butoxycarbonyloxy) styrene copolymer tert-butyl methacrylate / p- (tert-butoxycarbonyloxy) styrene copolymer Further polyester, polyimide, polyvinyl acetate, polyvinyl chloride Further, a decomposable and foamable functional group may be introduced into a low-hygroscopic polymer material selected from the group consisting of polyacrylonitrile, phenol resin, and dendrimer.
The decomposable compounds may be used alone or in combination of two or more different types. The decomposable compound becomes a low hygroscopic compound after the decomposable and foaming functional group is decomposed and eliminated to generate a bubble forming gas.

Foamable composition In addition to the acid generator or base generator and the decomposable foamable compound, other active energy ray-curable unsaturated organic compounds may be used in combination in the foamable composition used in the present invention. Examples of combination compounds include
(1) Aliphatic, alicyclic, aromatic 1-6 valent alcohols and polyalkylene glycol (meth) acrylates (2) Aliphatic, alicyclic, aromatic 1-6 valent alcohols with alkylene (Meth) acrylates of compounds obtained by adding oxide (3) Poly (meth) acryloylalkyl phosphate esters (4) Reaction products of polybasic acid, polyol and (meth) acrylic acid (5) Reaction product of isocyanate, polyol, (meth) acrylic acid (6) Reaction product of epoxy compound and (meth) acrylic acid (7) Reaction product of epoxy compound, polyol, (meth) acrylic acid (8) Melamine and A reaction product of (meth) acrylic acid can be mentioned.

Among the compounds that can be used in combination, curable monomers and resins can be expected to improve physical properties such as foam strength and heat resistance, and control foamability. Moreover, if a curable monomer is used for the decomposable compound and the combination compound, solvent-free molding can be performed, and a production method with less environmental load can be provided. For example, Patent Document 10 and Patent Document 19 use such materials.
Specific examples of the combination compound include methyl acrylate, ethyl acrylate, lauryl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, caprolactone-modified tetrahydrofurfuryl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, dicyclohexyl acrylate, isobornyl acrylate, isobornyl methacrylate, benzyl acrylate Benzylmeta Acrylate, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, methoxypropylene glycol acrylate, phenoxy polyethylene glycol acrylate, phenoxy polypropylene glycol acrylate, ethylene oxide modified phenoxy acrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, 2-ethylhexyl carbitol acrylate, ω-carboxypolycaprolactone monoacrylate, phthalic acid monohydroxyethyl acrylate, acrylic acid dimer, 2-hydroxy-3-phenoxypropyl acrylate, acrylic acid-9,10-epoxidized oleyl, ethylene maleate Glycol monoacrylate, disic Pentenyloxyethylene acrylate, acrylate of caprolactone adduct of 4,4-dimethyl-1,3-dioxolane, acrylate of caprolactone adduct of 3-methyl-5,5-dimethyl-1,3-dioxolane, polybutadiene acrylate, ethylene oxide modified Phenoxylated phosphate acrylate, ethanediol diacrylate, ethanediol dimethacrylate, 1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol di Methacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, 1,9-nonanediol dimethacrylate, di Ethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, neopentyl glycol diacrylate, 2-butyl-2-ethylpropanediol diacrylate, ethylene oxide modified bisphenol A diacrylate, Polyethylene oxide modified bisphenol A diacrylate, polyethylene oxide modified hydrogenated bisphenol A diacrylate, propylene oxide modified bisphenol A diacrylate, polypropylene oxide modified bisphenol A diacrylate, ethylene oxide modified isocyanuric acid diacrylate, pentaerythritol diacrylate monostearate 1,6-hexanediol diglycidyl ether acrylic acid adduct, polyoxyethylene epichlorohydrin modified bisphenol A diacrylate, trimethylolpropane triacrylate, ethylene oxide modified trimethylolpropane triacrylate, polyethylene oxide modified trimethylolpropane triacrylate, Propylene oxide modified trimethylolpropane triacrylate, polypropylene oxide modified trimethylolpropane triacrylate, pentaerythritol triacrylate, ethylene oxide modified isocyanuric acid triacrylate, ethylene oxide modified glycerol triacrylate, polyethylene oxide modified glycerol triacrylate, propylene oxide modified glycerol triacrylate Polypropylene oxide modified glycerol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, caprolactone modified dipentaerythritol hexaacrylate, polycaprolactone modified Although dipentaerythritol hexaacrylate etc. can be mentioned, it is not restricted to these.

Further, as part or all of the combined active energy ray-curable unsaturated organic compound, an active energy ray-curable resin having a (meth) acryloyl group at the molecular chain terminal and having a molecular weight of about 400 to 5000 can be combined. . As such a curable resin, for example, polyurethane poly (meth) acrylate polymers such as polyurethane-modified polyether poly (meth) acrylate and polyurethane-modified polyester poly (meth) acrylate are preferably used.
If necessary, the foamable composition used in the present invention includes an inorganic filler, silicone oil and processing aid, an organic filler as a softening agent, an ultraviolet absorber, a fluorescent brightener, an antioxidant, and a light stabilizer. Antifogging agents, antiblocking agents, other stabilizers, antistatic agents, antislip agents, colored dyes, metal soaps such as zinc stearate, and dispersing agents such as various surfactants, polyvalent isocyanate compounds, One or more epoxy compounds and reactive compounds such as organometallic compounds, lubricants, softeners, matting materials, flame retardants, and the like may be added. By using an additive, improvement in foaming properties, optical physical properties (particularly in the case of white pigments), electrical and magnetic properties (particularly in the case of conductive particles such as carbon black) and the like can be expected.

Specific examples of inorganic compound fillers include titanium oxide, magnesium oxide, aluminum oxide, calcium carbonate, silicon oxide, calcium silicate, calcium sulfate, magnesium sulfate, barium sulfate, magnesium carbonate, aluminum hydroxide, clay, talc, silica Kaolin, silicate clay, diatomaceous earth, zinc oxide, silicon oxide, magnesium hydroxide, calcium oxide, magnesium oxide, alumina, mica, asbestos powder, glass powder, shirasu balloon, zeolite and the like. Among them, calcium carbonate, barium sulfate, titanium oxide, magnesium carbonate, alumina, magnesium hydroxide and the like are preferable as an auxiliary agent for further improving the light reflectance. Two or more types may be mixed.
Examples of the organic compound filler include cellulose powder such as wood powder and pulp powder, and polymer beads. As the polymer beads, for example, those produced from acrylic resin, styrene resin or cellulose derivative, polyvinyl resin, polyvinyl chloride, polyester, polyurethane and polycarbonate, monomers for crosslinking, and the like can be used.
These fillers may be a mixture of two or more.

  Specific examples of the ultraviolet absorber are selected from salicylic acid-based, benzophenone-based, or benzotriazole-based ultraviolet absorbers. Examples of salicylic acid-based ultraviolet absorbers include phenyl salicylate, pt-butylphenyl salicylate, p-octylphenyl salicylate, and the like. Examples of the benzophenone ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone. Examples of the benzotriazole ultraviolet absorber include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-5'-t-butylphenyl) benzotriazole and the like.

  Specific examples of the antioxidant include monophenol-based, bisphenol-based, polymer-type phenol-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.

  A typical example of the light stabilizer is a hindered amine compound.

Softeners can be used for the purpose of improving processability and moldability. Specifically, ester compounds, amide compounds, hydrocarbon polymers having side chains, mineral oils, liquid paraffins, waxes, etc. Is mentioned.
The ester compound is not particularly limited as long as it is a mono- or polyester having a structure comprising an alcohol and a carboxylic acid, and may be a compound in which the hydroxyl group and carbonyl group ends are left in the molecule, or a compound blocked in the form of an ester group. . Specifically, stearyl stearate, sorbitan tristearate, epoxy soybean oil, refined castor oil, hydrogenated castor oil, dehydrated castor oil, epoxy soybean oil, extremely hardened oil, trioctyl trimellitic acid, ethylene glycol dioctanoate, pentaerythritol tetra Examples include octanoate.
The amide compound is not particularly limited as long as it is a mono- or polyamide compound having a structure composed of an amine and a carboxylic acid, and may be a compound in which the amino group and carbonyl group ends are left in the molecule, or a compound blocked in the form of an amide group. Good. Specifically, stearic acid amide, behenic acid amide, hexamethylene bis stearic acid amide, trimethylene bisoctylic acid amide, hexamethylene bishydroxy stearic acid amide, triocta trimellitic acid amide, distearyl urea, butylene bis stearic acid Amides, xylylene bis stearic acid amides, distearyl adipic acid amides, distearyl phthalic acid amides, distearyl octadecadioic acid amides, epsilon caprolactam, and derivatives thereof.
The hydrocarbon polymer having a side chain is preferably a poly α-olefin and classified into a normal oligomer having a side chain having 4 or more carbon atoms. Specifically, ethylene-propylene copolymer and its maleic acid derivative, isobutylene polymer, butadiene, isoprene oligomer and hydrogenated product thereof, 1-hexene polymer, polystyrene polymer and the like are derived from these. Derivatives thereof, hydroxypolybutadiene and hydrogenated products thereof, and terminal hydroxypolybutadiene hydrogenated products.

Production of Fibrous Foam About the production method of the fibrous foam of the present invention, that is, the production method of a fibrous foam obtained by forming the foamable composition into a fiber and then irradiating active energy rays and heating and foaming. Although described, it is not intended to limit the invention. The production method of the present invention may be a batch method or a continuous method, but the production process includes a molding process, an active energy ray irradiation process, and, if necessary, a heating foaming process. A cooling step may be provided after the heating and foaming step, and when a solution is used as a raw material, a drying step may be provided between the molding step and the active energy ray irradiation step. Further, other steps such as a stretching step and washing, drying, and relaxation may be appropriately added. An example of a continuous production method of a fibrous foam and a microporous nonwoven fabric using a spinning method is shown below.

  First, an example of a method for producing a fibrous foam applying the spinning method will be described. FIG. 1 shows an example of a continuous production method of a fibrous foam using a dry spinning method. The polymer solution obtained by dissolving the foamable composition of the present invention in a solvent is defoamed and filtered, heated to a predetermined temperature, and discharged from the pores of the spinneret 1 into the spinning cylinder 2. An inert gas heated to a temperature higher than the polymer solution temperature is introduced from the gas inlet 3 at the top of the spinning cylinder 2. In the spinning cylinder 2, the diffusion / evaporation of the solvent from the yarn into the heated gas and the thinning of the yarn proceed. The yarn coming out of the spinning cylinder 2 is falsely twisted by the false twisting machine 5, and this twist goes back the spinning cylinder 2 and reaches the single fiber joining point. Here, since the solvent concentration is still high, the contacted yarns fuse together to form a single yarn assembly. This coalescence is necessary in order to avoid quality troubles such as single yarn breakage in the subsequent process. As a false twisting method, there is a method using a liquid flow or a rotating roll in addition to the air jet method. The twist given by the false twisting machine 5 is released by tension before reaching the first roll 6. The yarn exiting the first roll 6 is irradiated with an electron beam by the electron beam irradiation device 7 and then heated to a predetermined temperature by the heater 8 to be foamed. After the yarn exiting the heater 8 is applied with the finishing agent by contacting the finishing roll 9, the yarn is wound up by the winding device 10. FIG. 2 shows an example of a continuous production method of a fibrous foam using a melt spinning method. The foamable composition of the present invention is melted by the melt extrusion apparatus 2 and extruded into the air from the pores of the spinneret 1, cooled by air cooling and the cooling pipe 3, solidified into a fibrous form, To reach. The yarn exiting the first roll 4 is irradiated with ultraviolet rays by the ultraviolet irradiation device 5 and then heated to a predetermined temperature by the heater 6 to be foamed. The yarn exiting the heater 6 is wound up by a winding device 7. After that, it may be further stretched. In the above, dry spinning and melt spinning have been taken as examples, but other spinning methods such as wet spinning and dry wet spinning can also be used. It is also possible to use residual heat at the time of spinning or heat the fiber and irradiate with active energy rays to cause foaming.

  Next, the example of the continuous manufacturing method of the nonwoven fabric which has a micropore is described. As an example of this production method, one using the burst fiber method can be mentioned. For example, as exemplified in Japanese Patent Application No. 2003-199515, which is the prior application of the present inventors, the foamable composition of the present invention formed into a film from a T-die is irradiated with an electron beam and foamed with a heater. Let And immediately after getting out of a heater, it is the method of blowing at room temperature or a cooler air, extending | stretching, opening and winding up, cooling. In the method of the present invention, unlike the conventional burst fiber method, at the time when foaming is caused in a film-like molded product, it has a micron order and even submicron order bubbles with a film thickness of several tens of μm, which cannot be obtained conventionally. A film-like foam can be easily obtained. By stretching and opening this, a nonwoven fabric having unprecedented thin and fine pores can be obtained.

  Examples of active energy rays used in the present invention include ionizing radiation such as electron beams, ultraviolet rays, and γ rays. In these, it is preferable to use an electron beam and an ultraviolet-ray. In the above example of the continuous production method, an example in which an electron beam is irradiated is shown.

When using electron beam irradiation, in order to obtain a sufficient transmission power, the acceleration voltage is 30 to 1000 kV, more preferably an electron beam accelerator of 30 to 300 kV, and the absorbed dose of one pass is controlled to 0.5 to 20 Mrad. It is preferable (1 rad = 0.01 Gy). If the accelerating voltage or the electron beam irradiation dose is lower than the above range, the transmission power of the electron beam will be insufficient, and it will not be possible to sufficiently penetrate the inside of the yarn. Not only deteriorates, but also the strength of the obtained yarn becomes insufficient, and the resin and additives contained therein are decomposed, and the quality of the obtained fibrous foam may be unsatisfactory. As the electron beam accelerator, for example, any of an electro curtain system, a scanning type, a double scanning type, or the like may be used, but a curtain beam type electron beam accelerator that can obtain a large output at a relatively low cost is used. preferable. When the oxygen concentration in the irradiation atmosphere is high during electron beam irradiation, generation of acid or base and / or curing of the curable decomposable compound may be hindered. Substitution with an inert gas such as carbon is preferred. The oxygen concentration in the irradiation atmosphere is preferably 1000 ppm or less, and more preferably 500 ppm or less in order to obtain more stable electron beam energy.
In the case of ultraviolet irradiation, an ultraviolet lamp generally used in the semiconductor / photoresist field or the ultraviolet curing field can be used. Typical UV lamps include, for example, halogen lamps, halogen heater lamps, xenon short arc lamps, xenon flash lamps, ultra high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, medium pressure mercury lamps, deep UV lamps, metal halide lamps. There are noble gas fluorescent lamps, krypton arc lamps, excimer lamps, etc., and in recent years, there are also Y-ray lamps that emit an extremely short wavelength (peak at 214 nm). Some of these lamps are ozone-less types that generate less ozone. These ultraviolet rays may be scattered light or parallel light with high straightness.

For ultraviolet irradiation, various lasers such as ArF excimer laser, KrF excimer laser, YAG laser via a harmonic unit including a nonlinear optical crystal, and ultraviolet light emitting diodes can be used. The emission wavelength of the ultraviolet lamp, laser, or ultraviolet light emitting diode is not limited as long as it does not interfere with the foaming property of the foamable composition. Preferably, the photoacid generator or the photobase generator is efficient in acid or base efficiency. The emission wavelength that is often generated is good. That is, an emission wavelength that overlaps with the photosensitive wavelength region of the photoacid generator or photobase generator to be used is preferable. Furthermore, the light emission wavelength which overlaps the maximum absorption wavelength or the maximum absorption wavelength in the photosensitive wavelength region of these generators is more preferable, and the generation efficiency tends to increase. The energy irradiation intensity of ultraviolet rays is appropriately determined depending on the foamable composition. When using an ultraviolet lamp with high irradiation intensity typified by various mercury lamps and metal halide lamps, productivity can be improved, and the irradiation intensity (lamp output) is preferably 30 W / cm or more. The integrated irradiation light quantity (J / cm ² ) of ultraviolet rays is obtained by adding the irradiation time to the energy irradiation intensity, and is appropriately determined depending on the foam composition and the desired bubble distribution. It may be set according to the extinction coefficient of the acid generator or base generator. For stable and continuous production, a range of 1.0 mJ / cm ^{2 to 20} J / cm ² is preferable. When using an ultraviolet lamp, the irradiation time can be shortened because the irradiation intensity is high. When using an excimer lamp or excimer laser, the irradiation intensity is weak, but it is close to a single light, so if the emission wavelength is optimized for the photosensitive wavelength of the generator, higher generation efficiency and foamability Is possible. When the amount of irradiation light is increased, heat generation may interfere with foaming properties depending on the ultraviolet lamp. At that time, a cooling treatment such as a cold mirror can be performed. As the irradiation method, any one of contact irradiation and projection irradiation can be adopted.

  Although there is no restriction | limiting in particular as a heater which can be used by heating foaming, What can be heated by induction heating, resistance heating, dielectric heating (and microwave heating), infrared heating, etc. can be illustrated. Examples include an electric or gas infrared dryer using radiant heat, a roll heater using electromagnetic induction, an oil heater using an oil medium, an electric heater, and a hot air dryer using these hot airs. In the case of dielectric heating or infrared heating, since the internal heating method directly heats the inside of the material, it is preferable to perform uniform heating instantaneously than an external heating method such as a hot air dryer. In the case of dielectric heating, high frequency energy having a frequency of 1 MHz to 300 MHz (wavelength 30 m to 1 m) is used. A frequency of 6 MHz to 40 MHz is often used. Among dielectric heating, especially microwave heating uses microwaves with a frequency of 300 MHz to 300 GHz (wavelength 1 m to 1 mm), but 2450 MHz and 915 MHz (same as microwave ovens) are often used. In the case of infrared heating, an electromagnetic wave having a wavelength of 0.76 to 1000 μm in the infrared region is used. Although the optimum band of the selected wavelength varies depending on the situation from the heater surface temperature and the infrared absorption spectrum of the material to be heated, a wavelength band of preferably 1.5 to 25 μm, more preferably 2 to 15 μm can be used.

In the following, the features and application examples regarding the structure of the fibrous foam produced by the method of the present invention will be described, but these do not limit the present invention. According to the method of the present invention, a fibrous foam that is unstretched and has a cell diameter of 10 μm or less and a thickness or thickness of about 50 μm can be easily obtained, and can be further refined and thinned by stretching. This foam can be used for various applications. If the fibrous foam is a single fiber, it can be made into a woven or knitted fabric, mixed with other materials such as pulp, squeezed into a sheet, sprayed onto other structures, or filled into clothing, living materials, industrial It can also be used as materials, medical supplies, electrical and electronic parts, and the like. The non-woven fabric can be used as it is, but can also be laminated with other structures.
In the method for producing a fibrous foam of the present invention, the bubble diameter can be controlled from several tens of nanometers to several tens of micrometers, and the foaming ratio can be controlled to several tens of times. Therefore, the properties of the resulting foam are shown in Japanese Patent Application No. 2003-199515. In addition, there are various characteristics such as optical characteristics, thermal characteristics, and electrical characteristics.

High-sensitivity fibers High-sensitivity fibers are attracting attention as clothing materials that are superior in terms of sensibility (sense) such as appearance, touch, texture, texture, and color. Many of such fibers are finely processed such as surface irregularities, irregular cross-sectional structures, and fineness differences. In the method of the present invention, only the portion that has been exposed to the active energy ray is foamed by heating, so that an irradiated / unirradiated portion is attached, or the foam structure easily changes depending on the active energy dose. It is possible to add surface irregularities, irregular cross-sections, fineness differences, etc. by foaming, and even foams with small diameters can be easily foamed.・ It is possible to improve functionality. Although depending on the fineness, the bubble diameter is about 10 nm to 10 μm, preferably about 10 nm to 1 μm.
In addition, fibrous foam that has bubbles with a bubble diameter of about 400 to 800 nm, which is close to the wavelength of visible light, in the core, and the surface layer of which is unfoamed, is a structure found in animal hair fibers. Special color developability can be obtained. The color developability means that even if the fineness is the same, the thickness and the gloss of the fiber surface appear to be completely different due to the difference between light and mixed colors. The texture and texture that cannot be obtained with conventional synthetic fibers. Can be issued. Light colors such as ivory and beige gray have little coloring effect and high fiber transparency, so that incident light almost linearly passes through the sheath part and reaches the core part, and light is emitted at the core part with a bubble diameter close to the wavelength of light. Are irregularly reflected and appear to be opaque as if an apparent inorganic material was added, thereby making them feel thicker. On the other hand, in the case of dark colors such as brown and black, since the coloring effect is large, most of the incident light is absorbed, the amount of irregular reflection at the core portion is reduced, and the opacity is visually weakened and felt fine. By using the method of the present invention, by lowering the initial temperature of heat foaming and raising the temperature in the later stage, an unfoamed skin layer can be obtained on the surface. It is easy to impart special foamability.

Low dielectric applications Recent fields of computers and communication equipment demand high-speed arithmetic processing, mass high-speed communication, portability, and portability, and low dielectric constant and small, thin, and lightweight insulation members are required. It has been. The fibrous foam of the present invention is reduced in dielectric constant and weight by foaming. With high-density mounting of communication equipment and electronic equipment, the cable core wire has been reduced in diameter, and a thin wire jacket having a thickness of 100 μm or less and a low dielectric constant is required. According to the present invention, it is possible to easily obtain an insulated body having a closed cell thickness of 100 μm or less. Since it is difficult for moisture to enter inside the clothing body due to the closed cells, it is possible to obtain a very thin wire clothing body without worrying about an increase in the dielectric constant due to moisture. In this case, the bubble diameter is 10 μm or less, preferably 1 μm or less.

Battery separator application A thin nonwoven fabric (porous body) can be obtained particularly with fine pores. It can be used for applications such as battery separators where thin holes are required. In this case, from the viewpoint of mechanical strength and ion permeability, the thickness is 10 to 500 μm, preferably 15 to 200 μm, the bubble diameter is 0.01 to 5 μm, preferably 0.1 to 2 μm, and the porosity is 30 to 85%, preferably Is 45-80%.

Heat insulation / heat insulation application The fibrous foam of the present invention has heat insulation / heat insulation properties, and can be used for heat insulation packaging materials, heat insulation containers, wall insulation, etc., and clothing that needs heat insulation. . In particular, since the thermal conductivity of air is remarkably reduced by air bubbles having a diameter of 10 to 100 nm close to the mean free path of 65 nm at normal pressure for heat conduction, it is possible to obtain ultra-low heat insulation that cannot be obtained conventionally. By using a nonwoven fabric (porous body) having a pore diameter of 10 to 100 nm for a vacuum heat insulator such as a refrigerator, it is possible to obtain a heat insulation performance equivalent to that of a conventional one without increasing the degree of vacuum.
It is also possible to improve the heat insulating properties of the paper or film by scrubbing the fibrous foam of the present invention into paper or by adding it to a paint and coating it on the film or paper surface. It can also be used for thermal paper, sublimation heat transfer paper, fusion heat transfer paper, image information recording paper such as electrophotographic paper, packaging paper such as food, and building materials such as wallpaper.

Lightweight and buoyant use The fibrous foam of the present invention can also be used in lightweight clothing and shoes. Furthermore, if the fibrous foam of the present invention is incorporated into paper, it can be used for ultra-lightweight high-concealment paper such as newspaper. It can also be used for resin material separation for material recycling. One of the easiest material separation methods is separation using the difference in buoyancy with respect to air and water, etc., but in the case of separation between resin materials, a large density difference cannot be obtained. I am struggling.

Wavelength-selective reflective and transmissive fibers The method for producing the fibrous foam of the present invention can control the bubble diameter from submicron order (0.1 to 1 μm) to micron order (1 to 10 μm). It is possible to obtain a fibrous foam that is selectively transmissive and reflective. For example, it is possible to obtain a fibrous foam that transmits the infrared region and reflects the visible ultraviolet region. FIG. 3 is a light transmission spectrum of a foam having bubbles having an average diameter of 0.3 μm, and it can be seen that there is wavelength selectivity. With this characteristic, for example, winter clothes and ski wear can protect the skin from ultraviolet rays, warm the body, and keep the body warm as a characteristic of the foam structure itself without adding an ultraviolet absorber, etc., so the effect continues. It's easy to do. Moreover, as an optical fiber, it can also use as a composite fiber which has this fibrous foam in a clad part (outer part) and has a fluorinated resin etc. in a core part (center part). In recent years, the light used in optical communication is infrared light, and this fibrous foam can behave as a transparent body that hardly scatters light with respect to infrared light because of its fine foaming. Further, the refractive index is lowered by foaming. Therefore, it is possible to confine and propagate light in the core. In these cases, the bubble diameter is preferably about the wavelength of ultraviolet light to visible light, that is, about 100 to 800 nm.

Light reflection, white, concealment fiber The fibrous foam of the present invention may have a foam structure having a submicron order (0.1-1 μm) cell diameter. It is known that Mie scattering showing strong light scattering occurs in a foam having a bubble diameter comparable to the wavelength of visible light. By optimizing the bubble diameter, it is possible to produce a fibrous foam having a high light reflectance, high whiteness, high concealing thickness or thickness of 50 μm or less. For high concealment applications, thin concealment apparel, high concealment thin leaf print paper, concealment label, light shielding container, shading film for agriculture and horticulture, concealment correction transfer tape member, substrate for high concealment thin material delivery slip, poster , Card materials, information recording paper (heat and pressure sensitive recording paper, electrophotographic paper, sublimation receiving paper, fusion heat transfer receiving paper, ink jet paper) support materials, packaging materials, bar code labels, bar code printer image receiving paper, maps , Dust-free paper, display board, white board, electronic white board, photographic paper, decorative paper, wallpaper, banknote, release paper, origami, calendar, tracing paper, slip, delivery slip, pressure sensitive recording paper, copy paper, clinical test paper, etc. Can be used. Highly reflective applications include LCD backlight reflectors, medical, photographic or liquid crystal light box reflectors, surface light source reflectors, reflectors for lighting such as fluorescent and incandescent lamps, internally illuminated display fixtures, and electrical appliances. Examples include a decorative sign member, a road sign member, a sticker member, and a blind member.
The above is a part of application examples of the fibrous foam of the present invention. In addition to these, it can also be used for a sound insulating material, a sound absorbing material, a buffer material, a substance permeable membrane and a filtration membrane, an adsorbent, a catalyst carrier, etc. utilizing the characteristics as foam.

  The present invention will be described in detail by the following examples, but the present invention is not limited to these examples. Unless otherwise specified, “parts” and “%” in the examples represent “parts by mass” and “mass%”, respectively.

<Example 1>
Bis (4-tert-butylphenyl) iodonium perfluorobutanesulfonate (trademark: BBI-109) as an iodonium salt-based acid generator with respect to 100 parts of a copolymer of tert-butyl methacrylate / acrylonitrile (weight ratio 50/50) 3 parts of Midori Chemical Co., Ltd.) was mixed and dissolved in dimethylformamide by heating to obtain a spinning dope with a solid content of 30%. This stock solution was heated to 130 ° C. and then discharged from a spinneret into an inert gas at 230 ° C. to obtain an undrawn yarn. Next, the undrawn yarn is drawn in boiling water, washed and dried, and further irradiated with an electron beam under an acceleration voltage of 200 kV, an absorbed dose of 9 Mrad, and an oxygen concentration of 500 ppm or less, and heated in a hot air oven at 120 ° C. to foam. I let you.
In order to confirm the foam structure of the obtained fibrous foam, the cross section was observed. That is, the sample was frozen and cleaved in liquid nitrogen, a gold vapor deposition treatment was performed on the cross section of the obtained resin layer, and this gold vapor deposition surface was used using a scanning electron microscope (trademark: S-510, manufactured by Hitachi, Ltd.). The cross-sectional structure was observed. From the cross-sectional structure, the foam thickness and the average cell diameter were determined, and the foaming ratio was determined by measuring the density. The foam thickness was measured from cross-sectional images (magnification: 2500 times) before and after heating and foaming observed with the electron microscope. For the bubble diameter, 100 bubbles were randomly selected from the observation image (magnification: 5000 times) of the cross section of the foamed resin layer, and the average of the diameters was selected. The foaming ratio is measured by the Archimedes method at room temperature, the density of foam (A), and the density (B) when the foam is dissolved in a solvent and re-formed to form an unfoamed state. Asked. The obtained fibrous foam had a fineness of 15 dtex, an average cell diameter of 0.3 μm, and an expansion ratio of 1.7 times.

<Example 2>
Bis (4-tert-butylphenyl) iodonium perfluorobutanesulfonate (trademark: BBI-109) as an iodonium salt-based acid generator with respect to 100 parts of a copolymer of tert-butyl methacrylate / acrylonitrile (weight ratio 50/50) 3 parts of Midori Chemical) were mixed and dissolved in acetone to obtain a solution having a solid content of 25%. This solution was coated on one side of a support made of silicon PET (MR-38: manufactured by Mitsubishi Polyester), and then left in a 110 ° C. hot air oven for 1 minute to evaporate and remove the solvent. Furthermore, an electron beam was irradiated under the conditions of an acceleration voltage of 200 kV, an absorbed dose of 9 Mrad, and an oxygen concentration of 500 ppm or less, and the coating film was peeled off from the support to obtain a resin film. The resin film was heated in a hot air oven at 130 ° C. to foam. Then, it was stretched by cooling and opened to obtain a nonwoven fabric having fine pores. The resulting nonwoven fabric had a thickness of 15 μm, pores of 0.5 μm or less, and a porosity of 50%.

<Example 3>
In the same manner as in Example 1, a fibrous foam having fine bubbles was produced. However, in the electron beam irradiation process of Example 1, ultraviolet rays were used instead of the electron beams used as active energy rays. This ultraviolet ray was irradiated using an ultraviolet ray irradiation apparatus (manufactured by USHIO INC.) Having a Y-ray lamp (peak wavelength: 214 nm) so that the irradiation dose was 3000 mJ / cm ² .
The foamed structure of the obtained fibrous foam was observed in the same manner as in Example 1. As a result, the fineness was 14 dtex, the average cell diameter was 0.4 μm, and the foaming ratio was 1.4 times.

  According to the present invention, it becomes possible to easily provide a fibrous foam made of independent or continuous foam having a fine foam structure by a foaming method that could not be obtained by a conventional method, so that clothing, living materials, industrial materials It contributes greatly to various fields such as medical supplies and electrical / electronic supplies.

Example of continuous production of fibrous foam using dry spinning Example of continuous production of fibrous foam using melt spinning Light transmission spectrum of foams with bubbles with an average diameter of 0.3μm

Explanation of symbols

1. Spinneret, 2. 2. Spindle, 3. 3. Gas inlet, 4. Gas outlet, False twisting machine, 6. First roll, 7. 7. electron beam irradiation device; 8. heater, Finishing agent roll, 10. Winding device
11． Melt extrusion equipment, 12. Cooling pipe, 13. UV irradiation device,

Claims (3)

Decomposing foam that contains an acid generator that generates an acid by the action of active energy rays or a base generator that generates a base, and further decomposes and desorbs one or more low-boiling volatile substances by reacting with the acid or base. A fibrous foam produced from a foamable composition containing a compound having a functional functional group. Decomposing foam that contains an acid generator that generates an acid by the action of active energy rays or a base generator that generates a base, and further decomposes and desorbs one or more low-boiling volatile substances by reacting with the acid or base. A method for producing a fibrous foam, comprising forming a foamable composition containing a compound having a functional functional group into a fibrous form and then irradiating with active energy rays to cause foaming. The method for producing a fibrous foam according to claim 2, wherein the foaming is carried out by heating after irradiation with active energy rays.

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