JP2011038193A - Cellulose fiber and fiber composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cellulose fiber that improves the thermal decomposition temperature and is uniformly dispersed in a matrix resin and a fiber composite material that uses the cellulose fiber and has improved dynamic characteristics and heat characteristics. <P>SOLUTION: The cellulose fiber is coated with a lignophenol derivative and has an average fiber diameter of not less than 2 nm and not more than 200 nm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a microfibrillated cellulose fiber whose surface is coated with a lignophenol derivative, and a 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, the glass fiber reinforced material achieves high rigidity, but has a limitation in weight reduction because of its high specific gravity. In addition, when disposing of this glass fiber reinforced material, the glass fiber itself is non-flammable, which causes problems such as damage to the combustion furnace during incineration and low combustion efficiency, making it suitable for thermal recyclability. There was also the disadvantage of not.

  As other fibrous reinforcements, fiber reinforcements made of organic materials such as polyester fibers, polyamide fibers, and aramid fibers have been studied, but fiber reinforcement materials containing these reinforcements can ensure light weight and thermal recyclability. However, there was a problem that the mechanical reinforcement effect was not sufficient.

  In recent years, reinforced resins to which plant fibers such as bamboo, kenaf, sugar cane, and wood are added have been studied, while high-functional materials using plant-derived materials are attracting attention from the viewpoint of carbon neutral (Patent Documents 1 and 2). ), All of the proposed composite materials have limited applications due to insufficient mechanical properties such as tensile modulus and flexural modulus.

  As a solution to these problems, a fiber composite material is proposed in which cellulose fibers that have been fibrillated and microfibrillated as described above are mixed with a resin. 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).

  For example, in Patent Document 3, as a method for preparing a fiber composite material, a microfibril cellulose fiber dispersion is subjected to a drying process, shaped into a sheet or block, etc., and then a fiber aggregate is cured. Although a method of impregnating and curing a functional monomer has been disclosed, the fiber once fibrillated is molded in a state of being agglomerated again, so that the dispersion state in the matrix resin is non-uniform (formation of agglomerated sites), There was a problem that unevenness in strength occurred in the resulting 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. However, since the dispersion in the resin is still insufficient and a high temperature process is used to melt the resin, the temperature at which the cellulose fibers are not thermally decomposed (less than 240 ° C., preferably less than 220 ° C.) or more Resins that melt at high temperatures cannot be used, and the matrix resins that can be used are limited. Therefore, in the conventional cellulose fiber, when producing a fiber composite material as a reinforcing material, since the thermal decomposition temperature is low, the matrix resin that can be used is limited, and its application range is limited. Moreover, since it is still difficult to disperse uniformly in the matrix resin, the resulting fiber composite material has insufficient mechanical strength and the effect of reducing the linear expansion coefficient is small.

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

  This invention is made | formed in view of the said subject, The objective provides the improvement of a thermal decomposition temperature, and the cellulose fiber which can be uniformly disperse | distributed to a matrix resin, Moreover, the said cellulose fiber was used. It is to provide a fiber composite material with improved mechanical properties and thermal properties.

  The above-mentioned problem according to the present invention is solved by the following means.

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

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

  3. 3. The cellulose fiber according to 1 or 2 above, wherein the cellulose fiber adsorbs inorganic ions.

  4). The fiber composite material characterized by including the cellulose fiber and matrix resin of any one of said 1-3.

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

  According to the present invention, it is possible to provide a cellulose fiber having improved heat resistance (thermal decomposition temperature) and good dispersibility in a matrix resin. Further, by dispersing the cellulose fiber in the matrix resin, a fiber composite material excellent in mechanical properties such as tensile strength and bending strength and thermal properties such as linear expansion coefficient can be obtained. The fiber composite material can be used for a wide range of applications such as housings for home appliances, substrate materials for electronic devices, automotive parts, housing interior materials, packaging and container materials.

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 relates to a cellulose fiber having an average fiber diameter of 2 nm to 200 nm coated with a lignophenol derivative, and a cellulose fiber composite material containing the cellulose fiber dispersed in a matrix resin.

  The present inventors have focused on cellulose fibers as a reinforcing material to be blended in the matrix resin, and as a result of earnestly examining the method for treating cellulose fibers, the average fiber diameter of plant cellulose fibers such as pulp is 2 nm or more, The surface of the obtained microfibrillated cellulose fiber was coated with a lignophenol derivative after defibration treatment to a range of 200 nm or less, thereby greatly improving the thermal decomposition temperature and improving the dispersibility in the matrix resin. It was found that cellulose fibers can be obtained. It was also found that the thermal decomposition temperature of the microfibrillated cellulose fiber was improved in advance and the dispersibility in the matrix resin was improved by using a surface modification in advance or a treatment for adsorbing inorganic ions. . Then, by mixing and dispersing the cellulose fiber coated with the surface-modified lignophenol derivative in the matrix resin, a fiber composite material having greatly improved mechanical properties and thermal properties could be obtained. In addition, since the thermal decomposition temperature of the cellulose fiber itself is improved, it becomes possible to melt and knead a thermoplastic resin having a relatively high melting temperature such as an aromatic polyester resin, a polyether sulfone resin, or a polyphenylene sulfide resin. Since a simple matrix resin 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, this invention is not limited to the following embodiments.

(Cellulose fiber)
The cellulose fiber according to the present invention is a cellulose fiber having an average fiber diameter of 2 nm or more and 200 nm or less and coated with a lignophenol derivative.

  Cellulose fibers used as raw materials include plant-derived pulp, wood, cotton, hemp, bamboo, cotton, kenaf, hemp, jute, banana, coconut, seagrass and other plant fibers, and sea animals squirts Examples thereof include fibers separated from animal fibers to be produced, 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 of the fibrillation treatment method, cellulose fibers such as pulp are introduced into a dispersion vessel containing water so as to be 0.1 to 3% by mass, and this is fibrillated with a high-pressure homogenizer to obtain average fibers. An aqueous dispersion of cellulose fibers defibrated in a microfibril shape having a diameter of about 0.1 to 10 μm is obtained. Further, 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 specific example, there is 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. Are known. 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 fibrillation 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.

  The cellulose fibers used in the present invention are microfibrillated cellulose fibers, which are cellulose microfibrils and crystalline fibers in which cellulose molecular chains are bonded by several tens of hydrogen bonds (one having a fiber diameter of 2 to 4 nm is the minimum). The unit structure is further bundled to form a hierarchical structure of fibers, and fibers having a fiber diameter of a micron level are formed according to the degree of defibration.

  In this invention, when the average fiber diameter of a cellulose fiber exceeds 200 nm, there exists a possibility that the intensity | strength at the time of setting it as 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 any other treatment such as defibration treatment using the high-pressure homogenizer or grinding treatment using a grinder.

  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.

(Measurement method of average fiber diameter and average fiber length)
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.). It is possible to select 100 fibers at random from an image, analyze the fiber diameter and the fiber length for each fiber using image processing software (WINROOF), and obtain a simple number average value thereof.

(Lignophenol derivative)
The lignophenol derivative used in the present invention is basically obtained from a lignocellulosic material containing lignin and treated with a phenol derivative. Examples of the lignocellulosic material include various materials mainly made of wood, such as wood flour, chips, waste materials, mill ends, and the like.

  A lignophenol derivative is obtained by treating lignin in a lignocellulosic material with a phenol derivative and extracting it from the lignocellulosic material as a lignophenol derivative. Examples of the method include lignocellulose such as wood flour. A method in which a liquid phenol derivative (cresol or the like) is infiltrated into a system material, lignin is solvated with a phenol derivative, and then a concentrated acid is added to dissolve the cellulose component. For example, JP-A-2-233701 And the like.

(Surface coating with lignophenol derivatives)
The cellulose fiber of the present invention is a cellulose fiber defibrated to an average fiber diameter of 2 nm or more and 200 nm or less, and the surface is coated with a lignophenol derivative. The cellulose constituting the plant exists as a lignocellulosic material containing lignin and hemicellulose, and the cellulose fiber containing 2 to 70% by mass of lignin that functions as an adhesive between cellulose fibers has a thermal decomposition temperature. It is known to be expensive (for example, JP 2009-19200 A). However, when the lignin content increases, it becomes difficult to form microfibrils, and even if such cellulose fibers are used as a resin reinforcing agent, the effect of improving physical properties such as mechanical strength is small. On the other hand, cellulose fibers obtained by fibrillation treatment of cellulose raw materials such as wood pulp that have been subjected to lignin removal treatment to reduce lignin content are easy to microfibrillate by defibration treatment, but the thermal decomposition temperature decreases. To do.

  On the other hand, in the present invention, after the cellulose having a lignin content of less than 50% by weight, preferably less than 30% by weight, more preferably less than 10% by weight, is fibrillated and microfibrillated, The surface of the cellulose fiber is coated with the lignin extracted by the lignin removal treatment as a lignophenol derivative. Thereby, the thermal decomposition temperature of the cellulose fibers is greatly improved, and the dispersibility of the cellulose fibers in the matrix resin is also improved. And about the fiber composite material obtained by disperse | distributing this to matrix resin, the thermal characteristics, such as the mechanical strength and a linear expansion coefficient, are improved greatly. In addition, since the cellulose fiber surface-coated with lignophenol has a high thermal decomposition temperature, it can be melt kneaded into a thermoplastic resin having a high melting temperature. For example, it can be applied to aromatic polyesters having a molding temperature of 280 ° C. or higher. A fiber composite material in which cellulose fibers are dispersed can be obtained.

  Cellulose fibers can be coated with lignophenol derivatives by chemically bonding them via hydroxyl groups or carboxyl groups on the surface of cellulose fibers, or by dispersing cellulose fibers in a solution in which lignophenol derivatives are dissolved in a solvent such as acetone. And adsorbing method.

  The coating amount of the lignophenol derivative 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.

(Surface modification of cellulose fiber)
As the cellulose fiber of the present invention, a microfibrillated cellulose fiber that is further surface-modified in addition to coating with lignophenol is preferably used. This is performed by chemically modifying the hydroxyl group of the cellulose fiber using a modifying agent such as an acid, an alcohol, a halogenating reagent, an acid anhydride, an isocyanate, or a silane coupling agent. In addition, the chemically defibrated cellulose fiber may be chemically modified using the introduced carboxyl group. The chemical modification method can be carried out in accordance with a known method. For example, after the fibrillated cellulose fiber is added and dispersed in water or an appropriate solvent, a chemical modifier is added thereto and an appropriate reaction is performed. 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 functional groups introduced into cellulose fibers coated with lignophenol by chemical modification include acetyl, methacryloyl, propanoyl, butanoyl, iso-butanoyl, pentanoyl, hexanoyl, heptanoyl, octanoyl, methyl Group, ethyl group, 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.

(Adsorption of inorganic ions)
As the cellulose fiber of the present invention, those having an inorganic ion adsorbed on the surface are preferably used. By adsorbing inorganic ions, the thermal decomposition temperature of the cellulose fiber can be further improved, and it becomes possible to use a technique such as melt-kneading with a thermoplastic resin that is exposed to a high temperature in the composite with the matrix resin. . Examples of inorganic ions used for adsorption include calcium ions, magnesium ions, sodium ions, potassium ions, lithium ions, aluminum ions, strontium ions, barium ions, radium ions, copper ions, silver ions, gold ions, zinc ions, and nickel. Examples of the ion include cobalt ion and the like, and calcium ion, magnesium ion, sodium ion, potassium ion, and lithium ion are preferable. The amount of inorganic ions adsorbed is usually 0.00001 to 20 parts by mass, preferably 0.0001 to 10 parts by mass, and more preferably 0.0001 to 5 parts by mass with respect to 100 parts by mass of the cellulose fiber. Examples of the method for adsorbing inorganic ions to cellulose fibers include a method of adsorbing inorganic ions by dispersing cellulose fibers in an appropriate solvent and adding an inorganic salt.

(Matrix resin)
Examples of matrix resins used in the present invention include vinyl resins, (meth) acrylic resins, amide resins, polycarbonate resins, polyester resins, silicone resins, fluorine resins, and the like. It is not limited. 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-based resin include a reaction product of bisphenol A or a bisphenol that is a derivative thereof and phosgene or phenyl dicarbonate.

  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 and 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 And an aliphatic polyester resin such as a copolymer of the above hydroxycarboxylic acid.

  The silicone resin preferably has an organic group such as an alkyl group or an aromatic group as a structural unit, and particularly preferably has an organic group such as a methyl group or a phenyl group. Specific examples of the silicone resin having such an organic group include dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, and modified products thereof.

  Examples of the fluororesin include tetrachloroethylene, hexpropylene, 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 ) And the like; 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. Triazine group-containing phenol compound; and the like.

  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 to the resin and melt-kneaded. Or a mixer having a stirring blade, etc., and extruding the molten composite resin material into a strand shape to pelletize, or pulverizing the obtained bulk composite material and putting it into a molding machine, depending on the use Mold into shape. In addition to the kneading method conventionally performed, it is preferable to use a melt kneading apparatus capable of elongational flow 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 mixing principle is based on the principle that the mixture is stretched, mixed, and finely dispersed as the flow rate changes when the resin composition passes through the large and small passages 2a, 2b, 2c, 2d. Is based.

  The addition amount of the cellulose fiber in this composite material 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. 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.

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

  In the examples, the physical properties of cellulose fibers and fiber composite materials were evaluated as follows.

<Method for evaluating physical properties of cellulose fiber and fiber composite material>
(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.

Example 1
<Preparation of cellulose fibers AV>
(Preparation of lignophenol derivatives)
A lignophenol derivative was obtained according to the method described in JP-A-2008-214231. 50 parts by mass of p-cresol was dissolved in 1700 parts by mass of acetone, added to 100 parts by mass of wood powder of hinoki lumber from which the extract was removed, and left for 10 hours. Acetone was removed, 500 parts by mass of sulfuric acid (72%) was added to the wood powder to which p-cresol was adhered, and the mixture was vigorously stirred at room temperature for 1 hour. After removing the acid by washing with water, the mixture was dried and extracted by adding 700 parts by mass of acetone, and the extract was concentrated to 300 parts by mass to obtain a lignophenol derivative solution.

  Next, 300 parts by mass of cyclopentyl methyl ether as a poor solvent was added dropwise to the above lignophenol derivative solution while stirring, and the deposited precipitate was collected by filtration and dried to obtain a lignophenol derivative.

(Production of cellulose fiber A)
Sulfuric acid bleached pulp obtained from conifers was added to pure water so as to be 0.1% by mass, and between rotating discs using a stone mill grinder (Pure Fine Mill KMG1-10; manufactured by Kurita Machinery Co., Ltd.) The cellulose fiber was defibrated by performing grinding treatment (rotation speed: 1500 revolutions / minute) passing through from the center to the outside 50 times (50 passes). 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.

(Preparation of cellulose fiber B)
10 parts by mass of the lignophenol derivative prepared above was dissolved in 100 parts by mass of acetone, and 40 parts by mass of cellulose fiber A was added thereto, followed by stirring at room temperature for 10 hours. Thereafter, acetone was distilled off under reduced pressure to obtain cellulose fiber B in which the cellulose fiber was coated with a lignophenol derivative. From the result of observation with a scanning electron microscope, the obtained cellulose fiber B was kept at an average fiber diameter of 4 nm.

(Production of cellulose fiber C)
To 500 parts by mass of a butyric anhydride / pyridine (molar ratio 1/1) solution, 10 parts by mass of microfibrillated cellulose fiber A 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 of cellulose fiber D)
Cellulose fiber D was obtained in the same manner as in the preparation of cellulose fiber B except that surface-modified cellulose fiber C 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 of cellulose fiber E)
In producing the cellulose fiber A, the cellulose fiber was defibrated by the same operation except that the grinding treatment using a stone mill was changed to 30 times, and the cellulose fiber E was 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 of cellulose fiber F)
Cellulose fiber F was obtained by the same operation except that cellulose fiber E was used instead of cellulose fiber A in preparation of cellulose fiber B. The obtained cellulose fiber was kept at an average fiber diameter of 40 nm from the result of observation with a scanning electron microscope.

(Preparation of cellulose fiber G)
Cellulose fiber G was obtained by the same operation except that cellulose fiber E was used instead of cellulose fiber A in preparation of cellulose fiber C. 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 of cellulose fiber H)
Cellulose fiber H was obtained in the same manner as in the preparation of cellulose fiber B, except that surface-modified cellulose fiber G was used instead of cellulose fiber A.

(Preparation of cellulose fiber I)
Cellulose fiber F was dispersed in a 0.01 mass% calcium hydroxide aqueous solution, stirred for 1 hour, and then dialyzed in distilled water for 2 days. The cellulose dispersion after dialysis was freeze-dried to obtain cellulose fiber I adsorbed with calcium ions.

(Production of cellulose fiber J)
Cellulose fiber J was obtained in the same manner as in the preparation of cellulose fiber I, except that cellulose fiber H coated with lignophenol was used instead of cellulose fiber F.

(Production of cellulose fiber K)
In producing the cellulose fiber A, the cellulose fiber was defibrated by the same operation except that the grinding treatment using a stone mill was changed to 20 times, and the cellulose fiber K was 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.

(Preparation of cellulose fiber L)
Cellulose fiber L was obtained by the same operation except that cellulose fiber K was used instead of cellulose fiber A in the production of cellulose fiber B. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 90 nm.

(Preparation of cellulose fiber M)
Cellulose fiber M was obtained by the same operation except that cellulose fiber K was used instead of cellulose fiber A in the production of cellulose fiber C. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 90 nm.

(Preparation of cellulose fiber N)
In the production of the cellulose fiber B, a cellulose fiber N was obtained by the same operation except that the surface-modified cellulose fiber M 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 90 nm.

(Production of cellulose fiber O)
In producing the cellulose fiber A, the cellulose fiber was defibrated by the same operation except that the grinding treatment using a stone mill was changed to 10 times, and the cellulose fiber O was 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.

(Preparation of cellulose fiber P)
Cellulose fiber P was obtained by the same operation except that cellulose fiber O was used instead of cellulose fiber A in the production of cellulose fiber B. 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 of cellulose fiber Q)
Cellulose fiber Q was obtained by the same operation except that cellulose fiber O was used instead of cellulose fiber A in the production of cellulose fiber C. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 200 nm.

(Preparation of cellulose fiber R)
In the production of the cellulose fiber B, a cellulose fiber R was obtained by the same operation except that the surface-modified cellulose fiber Q 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.

(Preparation of cellulose fiber S)
In producing the cellulose fiber A, the cellulose fiber was defibrated by the same operation except that the grinding process using a stone mill was changed to 5 times, and the cellulose fiber S was 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.

(Preparation of cellulose fiber T)
Cellulose fiber T was obtained by the same operation except that cellulose fiber S was used instead of cellulose fiber A in the production of cellulose fiber B. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 210 nm.

(Preparation of cellulose fiber U)
Cellulose fiber U was obtained by the same operation except that cellulose fiber S was used instead of cellulose fiber A in the production of cellulose fiber C. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 210 nm.

(Preparation of cellulose fiber V)
In the production of the cellulose fiber B, a cellulose fiber V was obtained by the same operation except that the surface-modified cellulose fiber U 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 210 nm.

(Pyrolysis temperature)
Table 1 shows the thermal decomposition temperatures of the cellulose fibers A to V.

  FIG. 1 shows that the pyrolysis temperature can be improved by coating the cellulose fiber with a lignophenol derivative. Moreover, it turns out that the thermal decomposition temperature can be further improved by surface-modifying the surface of the cellulose fiber to be used or by adsorbing inorganic ions. And since the cellulose fiber of this invention has high thermal decomposition temperature, it becomes possible to apply to the melt-kneading process which requires comparatively high temperature, such as an aromatic polyester resin, in the composite_body | complex to a thermoplastic matrix resin.

Example 2
<Production of Cellulose Fiber Composite Materials 201-213, 217-222>
Each raw material was dry blended according to the blending composition (parts by mass) shown in Tables 2 and 3 below, 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 ° C. for 24 hours, 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.) It used for the measurement. Table 2 shows the evaluation results of the bending elastic modulus and bending strength, the linear expansion coefficient, and the dispersibility of the cellulose fibers.

<Preparation of Cellulose Fiber Composite Material 214-216>
Each raw material was dry blended according to the composition (parts by mass) shown in Table 3 below, 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, about the obtained pellet, after vacuum-drying at 70 degreeC for 24 hours, using an injection molding machine (IS-80G type made by Toshiba Machine Co., Ltd.), a test piece for measuring physical properties: 150 mm x 50 mm x 2 mm was prepared, It used for various measurements. Tables 2 and 3 show the evaluation results of the bending elastic modulus and bending strength, the linear expansion coefficient, and the dispersibility of cellulose fibers.

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 (manufactured by 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 clear from the results of evaluation physical properties shown in Tables 2 and 3, the cellulose fiber composite materials 201 to 216 according to the present invention are excellent in mechanical strength and have a greatly reduced linear expansion coefficient. . Cellulose fiber composite materials 210, 211 and 215 produced using an aromatic polyester resin as the matrix resin showed particularly high effects.

Example 3
<Preparation of Cellulose Fiber Composite Materials 301-314>
According to the blending composition shown in Table 4 below, after blending the respective raw materials, 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 4.

In Table 4, 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 4, it can be seen that the cellulose fiber composite materials 301 to 308 according to the present invention are excellent in mechanical strength and have a significantly reduced linear expansion coefficient. Among them, the cellulose composite material 307 produced using the cellulose fiber J in which the surface of the cellulose fiber was previously modified or the inorganic ions were adsorbed showed a particularly high effect.

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 (5)

  A cellulose fiber having an average fiber diameter of 2 nm to 200 nm coated with a lignophenol derivative.   The cellulose fiber according to claim 1, wherein the cellulose fiber is surface-modified.   The cellulose fiber according to claim 1 or 2, wherein the cellulose fiber adsorbs inorganic ions.   A fiber composite material comprising the cellulose fiber according to claim 1 and a matrix resin.   The fiber composite material according to claim 4, wherein the matrix resin is an aromatic polyester resin.

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