JP2011052339A - Cellulose fiber and fiber composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a fiber composite material which is excellent in mechanical strength and linear expansion property, has a wide selection of matrix resins to be used, and can be applied to a wide application range of substrate materials for the chassis of home electronics and for electronic devices, automotive parts, residential interior materials, package-container materials, or the like. <P>SOLUTION: There is disclosed a cellulose fiber which is coated with an ionomer and has an average fiber diameter of 2 nm or more and 200 nm or less. The cellulose fiber has a modified surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a microfibrillated cellulose fiber whose surface is coated with an ionomer, and a cellulose fiber composite material composed of the cellulose fiber and a matrix resin.

  BACKGROUND ART Fiber reinforced composite materials whose strength and rigidity are greatly improved by blending various fibrous reinforcing materials with resins are widely used in industrial fields such as electric / electronics, machinery, automobiles, and building materials. As the fibrous reinforcing material blended in the fiber-reinforced composite material, glass fibers having excellent strength and lightness are mainly used. However, in the glass fiber reinforced material, although high rigidity is achieved, the specific gravity is large, so there is a limit to weight reduction. Also, when disposing of this glass fiber reinforced material, the glass fiber itself is non-flammable, so there are problems such as damaging the combustion furnace during incineration and low combustion efficiency, making it suitable for thermal recyclability. There was also the disadvantage of not.

  On the other hand, fiber reinforcement made of organic materials such as polyester fiber, polyamide fiber, and aramid fiber has been studied as a fibrous reinforcement, but fiber reinforcement materials containing these reinforcements are lightweight and thermal recyclable. Although it can be secured, there is a problem that the mechanical reinforcement effect is not sufficient.

  On the other hand, in recent years, reinforced resins to which plant fibers such as bamboo, kenaf, sugarcane, and wood are added have been studied, while high-functional materials using plant-derived materials are attracting attention from the viewpoint of carbon neutrality (Patent Document 1). 2) All of the proposed composite materials have limited applications because of insufficient mechanical properties such as tensile modulus and flexural modulus.

  On the other hand, in recent years, a fiber composite material in which cellulose fibers obtained by defibrating the plant fibers and microfibrillated is mixed with a resin has been proposed. It has been reported that when such microfibrillated cellulose fibers are used as a reinforcing material for a resin, the mechanical strength is improved and the linear expansion coefficient can be reduced (for example, Patent Documents 3 and 4).

  In Patent Document 3, as a method for preparing a fiber composite material, a microfibril-like cellulose fiber dispersion is subjected to a drying step, and then shaped into a sheet or block to form a fiber aggregate, and then a curable monomer is added thereto. Although a method for impregnating and curing the resin is disclosed, since the fiber once fibrillated is molded again in an aggregated state, the dispersion state in the matrix resin is non-uniform (formation of aggregated sites) and obtained. There was a problem in that unevenness of strength occurred in the composite material.

  On the other hand, Patent Literature 4 discloses a method of adding pulp to a molten resin using a twin-screw kneader, and melt-kneading and defibrating as a method of microfibrillating fibers and uniformly dispersing them in a matrix resin. Has been. However, since the dispersion in the resin is still insufficient and the resin is melted at a temperature higher than the temperature at which the cellulose fibers are not thermally decomposed (less than 240 ° C., preferably less than 220 ° C.), the resin melts at a high temperature. Cannot be used, and the matrix resin that can be used is limited.

  In addition, a method is disclosed in which inorganic fibers are adsorbed on fibrillated cellulose fibers and fibers having improved heat resistance are dispersed in a matrix resin (for example, Patent Document 5), but the dispersibility of the fibers in the matrix resin is disclosed. Since it is insufficient, the resulting fiber composite material is insufficient in terms of mechanical strength and thermal characteristics. Therefore, it is still difficult for the conventional fiber composite material to uniformly disperse cellulose fibers as a reinforcing material in the matrix. Therefore, the mechanical strength of the obtained fiber composite material is insufficient, and the linear expansion coefficient is reduced. Since the effect is small and the matrix resin is also limited, its application range is limited.

JP-A-5-92527 JP 2002-69208 A JP 2007-51266 A JP 2005-42283 A JP 2009-52016 A

  Conventional fiber composite materials have problems such as insufficient mechanical strength such as tensile strength and bending strength and low linear expansion characteristics, and the applicable resin is limited because the applicable matrix resins are limited. . The purpose of the present invention is excellent in mechanical strength and low linear expansion characteristics, and has a wide selection range of matrix resins to be used. Household appliance housings, electronic device substrate materials, automotive parts, housing interior materials, packaging / container materials, etc. It is to obtain a fiber composite material applicable to a wide range of uses.

  The object of the present invention is achieved by the following configurations.

  1. A cellulose fiber having an average fiber diameter of 2 nm to 200 nm coated with an ionomer.

  2. 2. The cellulose fiber according to 1 above, wherein the cellulose fiber is surface-modified.

  3. 3. A fiber composite material comprising the cellulose fiber according to 1 or 2 and a matrix resin.

  4). 4. The fiber composite material as described in 3 above, wherein the matrix resin is an aromatic polyester resin.

  According to the present invention, microfibrillated cellulose fibers having improved heat resistance (thermal decomposition temperature) and good dispersibility in a matrix resin can be obtained. By dispersing this in the matrix resin, it has excellent mechanical properties such as tensile strength and bending strength, and thermal properties such as linear expansion coefficient, and high melting point thermoplastic resins such as aromatic polyester resins can be used as the matrix resin. Therefore, a fiber composite material with a wide application range can be obtained.

Sectional drawing of an extensional flow kneading chamber is shown.

  Hereinafter, although this invention is demonstrated based on embodiment, it is not limited to these.

  The present invention is a cellulose fiber composite material comprising an ionomer-coated average fiber diameter of 2 nm or more and 200 nm or less, and a cellulose fiber composite material containing the cellulose fiber dispersed in a resin matrix. .

  The present inventors have focused on cellulose fibers as a reinforcing material to be blended in the resin matrix and, as a result of intensive studies on the surface treatment method for cellulose fibers, the average fiber diameter of plant cellulose fibers such as pulp is 2 nm or more. After the fibrillation treatment to a range of 200 nm or less, the surface of the obtained microfibrillated cellulose fiber is coated with an ionomer to significantly improve the thermal decomposition temperature and improve the dispersibility in the matrix resin. It was found that it can be obtained.

  Conventionally, it has been known to adsorb inorganic ions to fibrillated cellulose fibers and improve the heat resistance of the fibers, but because the dispersibility to the matrix resin is insufficient, the fibers are dispersed in the matrix resin. The fiber composite material obtained by this method was insufficient in terms of mechanical strength and thermal characteristics. In contrast, the present inventors coated the surface of the cellulose fiber with an ionomer having ions (a resin obtained by neutralizing an ionic polymer having an ionic group introduced into a polymer chain with a counter ion), thereby producing a fiber. Not only the heat resistance of itself, but also the dispersibility of the surface-coated cellulose fibers in the matrix resin can be greatly improved. The fiber composite material obtained by dispersing the surface-coated cellulose fibers is heat resistant. In addition, the present inventors have found that the mechanical strength is greatly improved and completed the present invention. It has also been found that the surface modification of the microfibrillated fiber further improves the thermal decomposition temperature of the fiber and further improves the dispersibility in the matrix resin. By mixing and dispersing the cellulose fiber whose surface is coated with an ionomer in the matrix resin, a fiber composite material with greatly improved mechanical and thermal properties can be obtained. In addition, since the thermal decomposition temperature of cellulose fibers is improved, it becomes possible to melt and knead into thermoplastic resins with relatively high melting temperatures such as aromatic polyester resins, and a wide range of matrix resins can be used. A fiber composite material having a wide application range can be obtained.

  Hereinafter, although the cellulose fiber of this invention and the fiber composite material using the same are demonstrated in more detail, it is not limited to the following embodiments.

(Raw cellulose fiber)
Examples of the raw material cellulose fiber used in the present invention are plant-derived pulp, wood, cotton, hemp, bamboo, cotton, kenaf, hemp, jute, banana, coconut, seaweed, etc. Examples include fibers separated from animal fibers produced by sea squirts, bacterial cellulose produced from acetic acid bacteria, and the like. Among these, fibers separated from plant fibers can be preferably used, but fibers obtained from plant fibers such as pulp and cotton are more preferable. In the present invention, these fibers are defibrated using a homogenizer, a grinder or the like to obtain a microfibrillated cellulose fiber, but as long as the contained cellulose maintains the fiber state, There is no restriction | limiting about the defibrillation processing method.

  In these celluloses, the degree of polymerization is generally said to be in the range of 1000 to 3000 (molecular weight, tens of thousands to several millions), and is an insoluble natural fiber. In the present invention, since the fiber diameter of the crystalline fibrils obtained by defibration is important, any insoluble natural fiber having a polymerization degree (molecular weight) in this range may be used.

  As a specific example, cellulose fibers such as pulp are introduced into a dispersion container containing water so as to be 0.1 to 3% by mass, and this is defibrated with a high-pressure homogenizer to obtain an average fiber diameter of 0.1 to 3%. An aqueous dispersion of cellulose fibers defibrated to about 10 μm microfibrils is obtained. Furthermore, by repeatedly grinding with a grinder or the like, nano-order cellulose fibers having an average fiber diameter of about 2 to 500 nm can be obtained. Examples of the grinder used for the grinding treatment include a pure fine mill (manufactured by Kurita Machinery Co., Ltd.).

  As another method, there is known a method using a high-pressure homogenizer that pulverizes cellulose fibers by jetting a dispersion of cellulose fibers at a high pressure of about 250 MPa from a pair of nozzles and colliding the jet flow with each other at high speed. It has been. Examples of the apparatus used include “Homogenizer” manufactured by Sanwa Machinery Co., Ltd., “Artemizer System” manufactured by Sugino Machine Co., Ltd., and the like. Furthermore, in addition to the above-mentioned mechanical defibration method, 2,1,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) is used as a catalyst to oxidize the primary hydroxyl group of the cellulose amorphous region to introduce carboxyl. Alternatively, a method of chemically defibrating by using electrostatic repulsion between fibrils may be used. The average fiber diameter of the cellulose fibers obtained by the fibrillation treatment in this manner is preferably 2 nm or more and 200 nm or less, more preferably 2 nm or more and 100 nm or less, and further preferably 4 nm or more and 40 nm or less.

  Cellulose fibers used in the present invention are cellulose microfibrils, in which units of crystalline fibers (with a fiber diameter of 2 to 4 nm being the smallest unit) in which cellulose molecular chains are bonded by several tens of hydrogen bonds are further bundled. A hierarchical structure of fibers is formed in the form, and fibers having a fiber diameter of a micron level are formed depending on the degree of defibration.

  The average fiber diameter shown here is an average value of the diameters of the fibers dispersed in the resin, and is obtained from the result of image observation using a transmission electron microscope or the like.

  In this invention, when the average fiber diameter of a cellulose fiber exceeds 200 nm, there exists a possibility that the intensity | strength of a fiber composite material may become inadequate. In addition, cellulose fibers having an average fiber diameter of less than 2 nm are difficult to obtain by defibrating using the high-pressure homogenizer or grinding using a grinder or the like.

  In the present invention, the length of the cellulose fiber is not particularly limited, but the average fiber length is preferably 50 nm or more, and more preferably 100 nm or more. If the average fiber length is shorter than 50 nm, the strength of the fiber composite material may be insufficient.

  In the present invention, the average fiber diameter and the average fiber length were measured after observing the obtained fibers at a magnification of 10,000 times using a transmission electron microscope, H-1700FA type (manufactured by Hitachi, Ltd.). 100 fibers were selected at random from the image, the fiber diameter and fiber length of each fiber were analyzed using image processing software (WINROOF), and a simple number average value was obtained.

(Ionomer)
The ionomer used in the present invention is an ionic polymer in which a small amount of ionic groups are introduced into the polymer chain. Typical ionomers include a host polymer such as polyethylene, polystyrene, tetrafluoroethylene, etc. An ionic polymer having a carboxylic acid group or sulfonic acid group introduced therein is neutralized with a metal ion or ammonium ion.

  As the ionomer used in the present invention, various types can be used. For example, a host polymer having a side chain ion group such as a carboxylic acid group or a sulfonic acid group partially in the main chain of the host polymer. Polymerized by neutralizing the molecule with metal ions (side chain ionomers) or host polymers or oligomers with ionic groups such as carboxylic acid groups at both ends. And the like (telechelic ionomer) or those having a cation in the main chain and an anion bound thereto (ionene).

As a counter ion for neutralizing the ionic group of the host polymer, for the host polymer having an anion, alkali metal ions such as Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ Alkaline earth metal ions such as Ba ²⁺ , transition metal ions such as Zn ²⁺ , Cu ²⁺ , Mn ²⁺ , Ni ²⁺ , Co ²⁺ , Co ³⁺ , Fe ³⁺ , and Cr ³⁺ are used. For the host polymer having a cation, anions such as Cl ⁻ , Br ⁻ and I ⁻ are used.

Such an ionomer is not particularly limited. For example, the side chain ionomer includes an ethylene-methacrylic acid copolymer ionomer, an ethylene-acrylic acid copolymer ionomer, and a propylene-methacrylic acid copolymer ionomer. , Propylene-acrylic acid copolymer ionomer, butylene-acrylic acid copolymer ionomer, ethylene-vinylsulfonic acid copolymer ionomer, styrene-methacrylic acid copolymer ionomer, sulfonated polystyrene ionomer, poly (vinylbenzylphosphonium salt) Ionomer, styrene-butadiene acrylic acid copolymer ionomer, etc., and telechelic type ionomer include telechelic polybutadiene acrylic acid ionomer, telechelic sulfonated polyethylene. Terephthalate ionomer, telechelic sulfonated polypropylene terephthalate ionomer, telechelic sulfonated poly (butylene terephthalate) ionomer and the like, and the ionene, aliphatic ionene include aromatic ionene the like. Of these ionomers, side chain type or telechelic type ionomers are preferable, and side chain type ionomers are more preferable, specifically, ethylene-methacrylic acid copolymers and ethylene-acrylic acid copolymers. Examples thereof include metal salts of Na ⁺ and Zn ⁺² . These may use only 1 type and may mix and use 2 or more types as needed.

(Surface coating of cellulose fiber with ionomer)
The cellulose fiber of the present invention is a cellulose fiber that has been defibrated to an average fiber diameter of 2 nm or more and 200 nm or less, and the surface is coated with the ionomer, that is, an ionic polymer having an ionic group introduced into a polymer chain. The surface is coated with a resin neutralized with ions. First, cellulose is fibrillated and microfibrillated, and then the surface of the cellulose fiber is coated with an ionomer containing the ions. As a method for coating the ionomer on the cellulose fiber, hydroxyl groups and carboxyls on the surface of the cellulose fiber are used. A method in which cellulose fibers are dispersed in a solution in which ionomers are chemically bonded via a group or in which an ionomer is dissolved in a solvent such as acetone, or adsorbed to the surface, or cellulose fibers are added to a melted ionomer and kneaded to form fibers. Although the method of making it coat | cover on the surface etc. is mentioned, it is not limited to these.

  The coating amount of the ionomer on the cellulose fiber is 1 to 100 parts by mass, preferably 1 to 70 parts by mass, more preferably 1 to 50 parts by mass per 100 parts by mass of the cellulose fiber. Cellulose fibers surface-coated with ionomers have a high thermal decomposition temperature, so that they can be melt kneaded into thermoplastic resins having a high melting temperature. For example, cellulose fibers can be applied to aromatic polyesters having a molding temperature of 280 ° C. or higher. A dispersed fiber composite material is obtained.

(Surface modification of cellulose fiber)
As the cellulose fiber of the present invention, a surface-modified microfibrillated cellulose fiber is preferably used, and the hydroxyl group of the cellulose fiber is selected from acids, alcohols, halogenating reagents, acid anhydrides, isocyanates, silane coupling agents, and the like. It is preferable to perform chemical modification using the modifying agent. In addition, the chemically defibrated cellulose fiber may be chemically modified using the introduced carboxyl group. The chemical modification can be carried out according to a known method. For example, after cellulose fiber that has been defibrated is added to water or an appropriate solvent and dispersed, then a chemical modifier is added to the reaction to perform an appropriate reaction. What is necessary is just to make it react on conditions.

  In this case, in addition to the chemical modifier, a reaction catalyst can be added as necessary. For example, pyridine, N, N-dimethylaminopyridine, triethylamine, sodium methoxide, sodium ethoxide, sodium hydroxide, etc. A basic catalyst or an acidic catalyst such as acetic acid, sulfuric acid, or perchloric acid can be used, but a basic catalyst such as pyridine is preferably used in order to prevent a decrease in reaction rate and degree of polymerization. The reaction temperature is preferably about 40 to 100 ° C. from the viewpoint of suppressing the deterioration of cellulose fibers such as yellowing and lowering of the degree of polymerization and ensuring the reaction rate. The reaction time may be appropriately selected depending on the modifier used and the processing conditions.

  Examples of the functional group to be introduced into the cellulose fiber by chemical modification include, for example, acetyl group, methacryloyl group, propanoyl group, butanoyl group, iso-butanoyl group, pentanoyl group, hexanoyl group, heptanoyl group, octanoyl group, methyl group, ethyl group, Examples include propyl group, iso-propyl group, butyl group, iso-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group and the like.

  When introducing a reactive group, for example, a silane coupling agent capable of introducing a reactive group is preferably used. For example, vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane , Silane coupling agents having vinyl groups such as methacryloxypropylmethyldimethoxysilane, epoxy groups such as glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, glycidoxypropylmethyldimethoxysilane, etc. And silane coupling agents having a mercapto group at the terminal, such as mercaptopropyltrimethoxysilane and mercaptopropyltriethoxysilane. Among these, those having an epoxy group or a vinyl group at the terminal are preferably used.

  One or two or more of these functional groups may be introduced. In particular, by introducing a functional group that is the same as or similar to the functional group possessed by the matrix resin, or a functional group having reactivity with the matrix resin, the affinity between the cellulose fiber and the matrix resin can be improved, Since it is possible to form a covalent bond between the fiber and the matrix resin, uniform dispersibility of the cellulose fiber in the matrix resin can be secured, and good mechanical strength, heat resistance, low linear expansion coefficient, etc. The effect of improving physical properties can be obtained.

(Matrix resin)
Examples of the matrix resin used in the present invention include vinyl resins, (meth) acrylic resins, amide resins, polycarbonate resins, polyester resins, cellulose resins, silicone resins, and fluorine resins. However, it is not limited to the resin types. Further, it is not limited to any one of a thermoplastic resin, a thermosetting resin, and an active energy ray curable resin such as an ultraviolet ray, and one kind or a plurality of kinds may be blended.

  Examples of the vinyl resin include homopolymers or copolymers of ethylene, propylene, styrene, butadiene, butene, isoprene, chloroprene, isobutylene, isoprene, or polyolefin resins such as cyclic polyolefin having a norbornene skeleton, vinyl chloride, Examples thereof include vinyl chloride resins such as vinylidene chloride, and vinyl acetate resins such as polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, and polyvinyl butyral.

  Examples of the (meth) acrylic resin include acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid 2- Ethylhexyl, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, hydroxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, (meth) acrylic acid 2 -Butoxyethyl, (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) ) Acrylamide, Nt-octyl (meth) a N-substituted (meth) acrylamides such as Riruamido like.

  Examples of the amide resins include aliphatic amide resins such as 6,6-nylon, 6-nylon, 11-nylon, 12-nylon, 4,6-nylon, 6,10-nylon, and 6,12-nylon. And aromatic polyamides composed of aromatic diamines such as phenylenediamine and aromatic dicarboxylic acids such as terephthaloyl chloride and isophthaloyl chloride or derivatives thereof.

  Examples of the polycarbonate resin include a reaction product of bisphenol A or a bisphenol that is a derivative thereof, and phosgene or phenyl dicarbonate.

  The cellulose resin is preferably a cellulose ester, for example, cellulose acetate, cellulose propionate, cellulose acetate propionate, cellulose butyrate, cellulose acetate butyrate, cellulose pivalate, cellulose caproate, cellulose acetate caproate. Etc.

  As the polyester resin, an aromatic polyester obtained by a copolymer of a diol such as ethylene glycol, propylene glycol, or 1,4-butanediol and an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, or naphthalenedicarboxylic acid. Resins, copolymers of diols with aliphatic dicarboxylic acids such as succinic acid and valeric acid, homopolymers or copolymers of hydroxycarboxylic acids such as glycolic acid and lactic acid, the diols and the aliphatic dicarboxylic acids Aliphatic polyesters such as acids and copolymers of the above hydroxycarboxylic acids.

  As said silicone resin, what has organic groups, such as an alkyl group and an aromatic group, as a structural unit is preferable, and what has organic groups, such as a methyl group and a phenyl group, is especially preferable. Specific examples of the silicone resin having such an organic group include dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, and modified products thereof.

  Examples of the fluororesin include polymers or copolymer resins such as tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride, and perfluoroalkyl vinyl ether. These may be used alone or in combination of two or more as required.

(Stabilizer)
In the fiber composite material of the present invention, one or more stabilizers selected from a phenol stabilizer, a hindered amine stabilizer, a phosphorus stabilizer, and a sulfur stabilizer may be additionally added. By appropriately selecting these stabilizers and adding them to the composite material, degradation of cellulose fibers and matrix resin during molding processing, or changes in physical properties such as heat resistance and light resistance of the fiber composite material in the usage environment are highly suppressed. be able to.

  As a preferable phenol-based stabilizer, conventionally known ones can be used, for example, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2 , 4-di-t-amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate and the like, and JP-A Nos. 63-179953 and 1-168643. Acrylate compounds described in Japanese Patent Publication No. 1; octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5 Di-t-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenylpropionate)) methane [ie pentaerythrmethyl- Tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenylpropionate))], triethylene glycol bis (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate) Alkyl-substituted phenolic compounds such as 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bisoctylthio-1,3,5-triazine, 4-bisoctylthio-1, 3,5-triazine, 2-octylthio-4,6-bis (3,5-di-t-butyl-4-oxyanilino) -1,3,5-triazine, etc. And triazine group-containing phenolic compounds.

  Preferred hindered amine stabilizers include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, bis ( 1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (N-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (N-benzyloxy-2, 2,6,6-tetramethyl-4-piperidyl) sebacate, bis (N-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6) -Pentamethyl-4-piperidyl) 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-butylmalonate, bis (1-acryloyl-2,2,6 6-tetramethyl-4-piperidyl) 2,2-bis (3,5-di-t-butyl-4-hydroxybenzyl) -2-butylmalonate, bis (1,2,2,6,6-pentamethyl) -4-piperidyldecanedioate, 2,2,6,6-tetramethyl-4-piperidylmethacrylate), 4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy]- 1- [2- (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy) ethyl] -2,2,6,6-tetramethylpiperidine, 2-methyl-2- (2 , 2,6,6-tetramethyl-4-piperidyl) amino-N- (2,2,6,6-tetramethyl-4-piperidyl) propionamide and the like.

  Further, the preferable phosphorus stabilizer is not particularly limited as long as it is usually used in the general resin industry. For example, triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonyl) Phenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9 Monophosphite compounds such as 1,4-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 4,4'-butylidenebis (3-methyl-6-tert-butylphenyl-di-tridecyl phosphite ), 4,4'-isopropylidenebis (phenyl-di-alkyl (C12-C15) phosphine) Ito) diphosphite compounds such as and the like. Among these, monophosphite compounds are preferable, and tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite and the like are particularly preferable.

  Further, preferable sulfur stabilizers include, for example, dilauryl 3,3-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3- Thiodipropionate, pentaerythritol-tetrakis (β-laurylthio-propionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, etc. It is done.

  Although the compounding quantity of these stabilizers is suitably selected in the range which does not impair the objective of this invention, it is 0.01-2 mass parts normally with respect to 100 mass parts of resin compositions, Preferably it is 0.01-1 mass. Part.

(Method for producing fiber composite material)
Next, the manufacturing method of the cellulose fiber composite material of this invention is demonstrated. First, the case where a thermoplastic resin is used as the matrix resin will be described. As a method of dispersing the cellulose fibers in the thermoplastic resin, first, the matrix resin is melted and then the cellulose fibers are added and melt-kneaded, but the apparatus used is a commercially available twin-screw kneading extruder, For example, a mixer having a stirring blade may be used. The molten composite resin material may be extruded into a strand shape to be pelletized, or the obtained bulk composite material may be pulverized and put into a molding machine to be shaped according to the application. Mold. In addition to the kneading method conventionally performed, it is preferable to use a melt-kneading apparatus capable of elongational fluid mixing because the cellulose fibers can be more uniformly dispersed in the matrix resin.

  Elongating fluid mixing is a flow path having a large cross section cut from a cross section obtained by cutting a molten composition containing a matrix resin and a mixture in a plane perpendicular to the flow direction of the material, to a slit-shaped path having a smaller flow path. This is a kneading method in which the mixture is crushed and dispersed in a small amount by allowing it to flow in and passing through a predetermined length. Specific examples include a melt kneading method using a kneading apparatus equipped with an extension flow kneading die developed by Utracki et al. Described in US Pat. No. 5,451,106, for example, FIG. The method of kneading | mixing using the kneading apparatus provided with the expansion | extension flow kneading | mixing chamber 1 which has a large and small annular flow path as shown in FIG.

  FIG. 1 shows a cross-sectional view parallel to the flow path of the resin composition. The kneading of the resin composition is performed by first moving from the first annular channel 2a to the first slit channel 2b and passing through the first slit channel 2b, and from the second annular channel 2c. The extension fluid mixing is performed in two stages, that is, when moving to the second slit channel 2d and passing through the second slit channel 2d. The principle of the mixing is based on the principle that the mixture is stretched and mixed and finely dispersed in accordance with the change in flow velocity when the resin composition passes through the large and small passages 2a, 2b, 2c and 2d. Is based.

  The addition amount of the cellulose fiber in the fiber composite material is preferably 10 to 90 parts by mass, and more preferably 20 to 70 parts by mass with respect to 100 parts by mass of the fiber composite material. Moreover, when melt-kneading, additives such as the stabilizer and surfactant can be added as necessary.

  Next, when obtaining a molded object using the obtained pellet, the method similar to the normal molding method of a thermoplastic resin composition can be applied. Specifically, it may be carried out by methods such as injection molding, extrusion molding, compression molding, and hollow molding. First, the pellets and pulverized material are dried and then put into a molding machine equipped with a mold having a predetermined shape. Can be molded. In addition, in order to obtain a sheet-like molded body, in addition to melt molding, a resin solution in which fibers are dispersed is prepared by adding the cellulose fiber to a solution in which the resin is dissolved and stirring, and then casting this. Alternatively, it may be produced by a method of removing the solvent.

  Next, a case where a curable resin is used as the matrix resin will be described. The matrix resin can be cured by any one of irradiation with ultraviolet rays and electron beams, or heat treatment, and the cellulose fiber and the monomer forming the matrix resin are mixed in an uncured state, and further if necessary It is obtained by preparing a cellulose fiber-containing monomer composition to which an additive such as a stabilizer or a surfactant is added and then curing it. The addition amount of the cellulose fiber is preferably 10 to 90 parts by mass, more preferably 20 to 70 parts by mass with respect to 100 parts by mass of the fiber composite material. In preparing the cellulose fiber-containing monomer composition before curing, known methods can be appropriately employed. For example, when the properties of the prepared fiber-containing composition are liquid, each component is assigned. After mixing in a fixed amount, it is dissolved and mixed, or mixed uniformly with a mixer, blender, etc., and then kneaded with a kneader, roll, etc. to obtain a liquid curable resin composition, and a fiber-containing composition to be prepared If the property is solid, mix each component in a predetermined amount and mix by dissolution, or mix uniformly with a mixer, blender, etc., then heat knead with a kneader, roll, etc. A solid fiber-containing composition can be obtained.

  As a method for curing the fiber-containing monomer composition, when the matrix resin is ultraviolet and electron beam curable, a composition in which a photopolymerization initiator is added to a light-transmitting mold having a predetermined shape as necessary. Or is applied onto a substrate and then cured by irradiation with ultraviolet rays and electron beams.

  Examples of the photopolymerization initiator used here include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine. Carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) ) Photoradical initiation of 2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, etc. Etc. The. On the other hand, when the matrix resin is thermosetting, after preparing a monomer composition to which a thermal polymerization initiator such as a thermal radical generator is added as necessary, it is thermoset by compression molding, transfer molding, injection molding, or the like. be able to. Examples of the thermal polymerization initiator used here include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4- Azo compounds such as methoxy-2,4-dimethylvaleronitrile), organic peroxides such as benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1′-bis (t-butylperoxy) cyclohexane, etc. It is done.

(Physical property evaluation method for fiber composite materials)
The physical properties of the fiber composite material are evaluated by the following method. Evaluation in Examples was also performed by this method.

(1) Thermal decomposition temperature of cellulose fiber Using a TG / DTA apparatus (manufactured by SII (Seiko Instruments)), the mass reduction was measured at a heating rate of 10 ° C./min in a nitrogen atmosphere. The temperature was defined as the thermal decomposition temperature.

(2) Bending elastic modulus and bending strength A fiber composite material molded into a plate shape is cut out by 140 mm × 12 mm × 2 mm, and is measured by an autograph (“DSS-500” type, manufactured by Shimadzu Corporation) with a fulcrum distance of 80 mm and a bending speed of 2 mm / The bending elastic modulus and bending strength were measured at 20 ° C. for 5 minutes.

(3) Linear expansion coefficient About the said molded object, temperature was changed within the range of 40-80 degreeC, and the linear expansion coefficient was measured. SII (Seiko Instruments) EXSTAR6000 TMA / SS6100 was used as a measuring device.

(4) Dispersibility of cellulose fiber The molded body was visually observed, and the uniformity was evaluated based on the presence or absence of fiber aggregates.

  Examples of the present invention are shown below, but the present invention is not limited to these Examples.

(Production Example 1)
Using a stainless steel reactor equipped with a stirrer, 1 part by weight of 3-carboxybenzenesulfonic acid sodium salt is added to 100 parts by weight of 1,4-butanediol while stirring, and a catalytic amount of tetrabutoxy titanate is added thereto. And kept at 230 ° C. for 1 hour. Next, the reaction mixture was cooled to 180 ° C., and 220 parts by mass of dimethyl terephthalate was added. The temperature was then raised to 215 ° C. and held for 2 hours. The temperature was then raised to 245 ° C. over 30 minutes. The reaction vessel was depressurized to keep the pressure at 0.1 mbar, and the polymerization reaction was carried out while removing methanol from the reaction vessel to obtain a telechelic sulfonated polyester.

(Production Example 2)
A suspension obtained by adding sulfite bleached pulp obtained from conifers to 0.1% by mass in pure water is rotated using a stone mill grinder (Pure Fine Mill KMG1-10; manufactured by Kurita Machinery Co., Ltd.). The cellulose fibers were defibrated by performing grinding treatment (rotation number: 1500 revolutions / minute) 50 times (50 passes) for passing between the disks to be moved outward from the center. This aqueous dispersion was filtered, washed with pure water, and dried at 70 ° C. to obtain cellulose fibers A. From the result of observation with a scanning electron microscope, it was confirmed that the obtained cellulose fiber was fibrillated to an average fiber diameter of 4 nm and was microfibrillated.

(Production Example 3)
Ethylene-acrylic acid copolymer ionomer (manufactured by Mitsui DuPont, Himilan 1706 (Zn ²⁺ metal salt)) is dissolved in 100 parts by mass of acetone, and 40 parts by mass of cellulose fiber A obtained in Production Example 2 is dissolved therein. The mixture was added and stirred at room temperature for 10 hours. Thereafter, acetone was distilled off under reduced pressure to obtain cellulose fiber B in which the ionomer was adsorbed on the cellulose fiber. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 4 nm.

(Production Example 4)
To 500 parts by mass of an acetic anhydride / pyridine (molar ratio 1/1) solution, 10 parts by mass of the microfibrillated cellulose fiber A obtained in Production Example 2 was added and dispersed, followed by stirring at room temperature for 3 hours. Next, the dispersed fiber was filtered, washed three times with 500 parts by mass of water, and then washed twice with 200 parts by mass of ethanol. Furthermore, after washing twice with 500 parts by mass of water, it was dried at 70 ° C. to obtain surface-modified cellulose fibers C. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 4 nm.

(Production Example 5)
Cellulose fiber D was obtained in the same manner as in Production Example 3 except that surface-modified cellulose fiber C obtained in Production Example 4 was used instead of cellulose fiber A. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 4 nm.

(Production Example 6)
In Production Example 2, cellulose fibers were defibrated by the same operation except that the grinding treatment using a stone mill was changed to 30 times, and cellulose fibers E were obtained. The obtained cellulose fibers were confirmed to have been fibrillated to an average fiber diameter of 40 nm and microfibrillated from the results of observation with a scanning electron microscope.

(Production Example 7)
Cellulose fiber F was obtained by the same operation except that cellulose fiber E obtained in Production Example 6 was used instead of cellulose fiber A in Production Example 3. The obtained cellulose fiber was kept at an average fiber diameter of 40 nm from the result of observation with a scanning electron microscope.

(Production Example 8)
Cellulose fiber G was obtained in the same manner as in Production Example 4 except that cellulose fiber E obtained in Production Example 6 was used instead of cellulose fiber A. The obtained cellulose fiber was kept at an average fiber diameter of 40 nm from the result of observation with a scanning electron microscope.

(Production Example 9)
Cellulose fibers H were obtained in the same manner as in Production Example 3, except that the modified cellulose fibers G obtained in Production Example 8 were used instead of the cellulose fibers A. The obtained cellulose fiber was kept at an average fiber diameter of 40 nm from the result of observation with a scanning electron microscope.

(Production Example 10)
To 500 parts by mass of a butyric anhydride / pyridine (molar ratio 1/1) solution, 10 parts by mass of the microfibrillated cellulose fiber E obtained in Production Example 6 was added and dispersed, followed by stirring at room temperature for 3 hours. Next, the dispersed fiber was filtered, washed three times with 500 parts by mass of water, and then washed twice with 200 parts by mass of ethanol. Furthermore, after washing twice with 500 parts by mass of water, it was dried at 70 ° C. to obtain surface-modified cellulose fiber I. The obtained cellulose fiber was kept at an average fiber diameter of 40 nm from the result of observation with a scanning electron microscope.

(Production Example 11)
Cellulose fiber J was obtained in the same manner as in Production Example 3, except that Cellulose Fiber I obtained in Production Example 10 was used instead of Cellulose Fiber A. The obtained cellulose fiber was kept at an average fiber diameter of 40 nm from the result of observation with a scanning electron microscope.

(Production Example 12)
10 parts by mass of the telechelic sulfonated polyester obtained in Production Example 1 is dissolved in 100 parts by mass of acetone, and 40 parts by mass of the cellulose fiber I obtained in Production Example 10 is added thereto and stirred at room temperature for 10 hours. did. Thereafter, acetone was distilled off under reduced pressure to obtain cellulose fiber K in which the ionomer was adsorbed on the cellulose fiber. The obtained cellulose fiber was kept at an average fiber diameter of 40 nm from the result of observation with a scanning electron microscope.

(Production Example 13)
Cellulose fibers were defibrated in the same manner as in Production Example 2 except that the grinding treatment using a stone mill was changed to 20 times, and cellulose fibers L were obtained. From the observation result of the scanning electron microscope, the obtained cellulose fiber was confirmed to be fibrillated to an average fiber diameter of 90 nm and microfibrillated.

(Production Example 14)
Cellulose fiber M was obtained in the same manner as in Production Example 3 except that cellulose fiber L obtained in Production Example 13 was used instead of cellulose fiber A. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 90 nm.

(Production Example 15)
Cellulose fiber N was obtained by the same operation except that cellulose fiber L obtained in Production Example 13 was used instead of Cellulose Fiber A in Production Example 4. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 90 nm.

(Production Example 16)
Cellulose fibers O were obtained in the same manner as in Production Example 3, except that the modified cellulose fibers N obtained in Production Example 15 were used instead of the cellulose fibers A. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 90 nm.

(Production Example 17)
Cellulose fibers were defibrated in the same manner as in Production Example 1 except that the grinding treatment using a stone mill was changed to 10 times, and cellulose fibers P were obtained. From the observation result of the scanning electron microscope, the obtained cellulose fiber was confirmed to be fibrillated to an average fiber diameter of 200 nm and to be microfibrillated.

(Production Example 18)
Cellulose fiber Q was obtained by the same operation except that cellulose fiber P obtained in Production Example 17 was used instead of cellulose fiber A in Production Example 3. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 200 nm.

(Production Example 19)
Cellulose fiber R was obtained in the same manner as in Production Example 4 except that cellulose fiber P obtained in Production Example 17 was used instead of cellulose fiber A. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 200 nm.

(Production Example 20)
In Production Example 3, cellulose fiber S was obtained in the same manner except that the modified cellulose fiber R obtained in Production Example 19 was used instead of the cellulose fiber A. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 200 nm.

(Production Example 21)
Cellulose fibers were defibrated in the same manner as in Production Example 1 except that the grinding treatment using a stone mill was changed to 5 times, and cellulose fibers T were obtained. From the observation result of the scanning electron microscope, the obtained cellulose fibers were confirmed to be fibrillated to an average fiber diameter of 210 nm and microfibrillated.

(Production Example 22)
Cellulose fiber U was obtained in the same manner as in Production Example 3 except that cellulose fiber T obtained in Production Example 21 was used instead of cellulose fiber A. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 210 nm.

Example 1
Table 1 shows the thermal decomposition temperatures of the cellulose fibers prepared in Production Examples 2 to 22.

  The thermal decomposition temperature can be improved by adsorbing the ionomer to the cellulose fiber. In addition, since the thermal decomposition temperature can be further improved by chemical modification of the cellulose fiber surface in advance, it can be applied to a melt-kneading process that requires a relatively high temperature, such as an aromatic polyester resin, in combination with a thermoplastic matrix resin. It becomes possible.

Example 2
(Creation of fiber composite materials 101-112, 116-121)
Each raw material was dry blended according to the blending composition (parts by mass) shown in Tables 2 and 3, and then dried at 60 ° C. for 12 hours using a vacuum dryer. Next, using a twin-screw extruder (TEM35 type manufactured by Toshiba Machine Co., Ltd.), the mixture was melt-kneaded at a barrel temperature of 180 to 280 ° C., a screw rotation speed of 200 rpm, and a discharge rate of 10 kg / h, and discharged from the tip of the extruder. The resin was cut into pellets to obtain pellets of the resin composition. About the obtained pellet, after vacuum-drying at 70 degreeC for 24 hours, the test piece for physical property measurement (150 mm x 50 mm x 2 mm) was created using the injection molding machine (IS-80G type made by Toshiba Machine Co., Ltd.). It used for the measurement. The evaluation results are shown in Tables 2 and 3.

Example 3
(Creation of fiber composite materials 113 to 115)
Each raw material was dry blended according to the composition (parts by mass) shown in Table 2, and then dried at 60 ° C. for 12 hours using a vacuum dryer. Next, using an extension flow kneader equipped with the extension flow kneading chamber shown in FIG. 1 in the molten resin discharge section, the mixture is melt kneaded under conditions of a barrel temperature of 180 to 280 ° C. and a discharge rate of 10 kg / h, and an extruder The resin discharged from the tip was cut into pellets to obtain fiber composite material pellets. Moreover, after vacuum-drying the obtained pellet for 24 hours at 70 ° C., a test piece for measuring physical properties (150 mm × 50 mm × 2 mm) was prepared using an injection molding machine (IS-80G type manufactured by Toshiba Machine Co., Ltd.). The sample was subjected to various measurements. The evaluation results are shown in Table 2.

In addition, the detail of compounding components other than the component described in the manufacture example in Table 2, 3 is as follows.
Aromatic polyester resin: Polyethylene terephthalate resin (manufactured by Teijin Chemicals Ltd.)
Aliphatic polyester resin: Polylactic acid (Lacia H-400, manufactured by Mitsui Chemicals)
Polycarbonate resin: Iupilon S1000 (Mitsubishi Engineer Plastics)
Stabilizer A: Tetrakis (1,2,2,6,6-pentamethylpiperidyl) butanetetra
Carboxylate stabilizer B: 2,2'-methylenebis (4,6-di-t-butylphenyl) -2-ethyl
Hexyl phosphite As is apparent from the physical property evaluation results shown in Tables 2 and 3, the fiber composite materials 101 to 115 according to the present invention are excellent in mechanical strength and have a significantly reduced linear expansion coefficient.

Example 4
(Creation of fiber composite materials 201-214)
According to the composition shown in Tables 4 and 5, after blending each raw material, a thermosetting resin composition was obtained by kneading using a kneader. After filling the obtained resin composition into a mold having dimensions of 150 mm × 50 mm × 2 mm, the plate-like fiber composite material was heated and pressed under the conditions of 120 ° C. and 1.33 × 10 ⁻³ MPa. A molded body was obtained. The evaluation results are shown in Table 3.

In Tables 4 and 5, the details of the components other than the monomers and the components described in the production examples are as follows.
Polymerization initiator: Azobisisobutyronitrile stabilizer A: Tetrakis (1,2,2,6,6-pentamethylpiperidyl) butanetetra
Carboxylate stabilizer B: 2,2'-methylenebis (4,6-di-t-butylphenyl) -2-ethyl
Hexyl phosphite As is apparent from the physical property evaluation results in Table 3, it can be seen that the fiber composite materials 201 to 208 according to the present invention are excellent in mechanical strength and have a significantly reduced linear expansion coefficient.

DESCRIPTION OF SYMBOLS 1 Elongation flow kneading chamber 2 Elongation flow kneading part 2a 1st flow path 2b 1st slit flow path 2c 2nd flow path 2d 2nd slit flow path 3 Resin composition supply port 4 Resin composition discharge port

Claims (4)

A cellulose fiber having an average fiber diameter of 2 nm to 200 nm coated with an ionomer. The cellulose fiber according to claim 1, wherein the cellulose fiber is surface-modified. A fiber composite material comprising the cellulose fiber according to claim 1 or 2 and a matrix resin. The fiber composite material according to claim 3, wherein the matrix resin is an aromatic polyester resin.

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