阅读说明：本技术 纤维素纳米纤维的制造方法 (Cellulose nano-fibrous manufacturing method ) 是由 神谷大介 松木诗路士 于 2018-06-01 设计创作，主要内容包括：本发明的目的在于提供一种在纤维素纳米纤维中不残留TEMPO等N-氧基化合物、且利用高效的方法制造纤维素纳米纤维的方法。一种纤维素纳米纤维的制造方法,其包括以下步骤：使用有效氯浓度为14～43质量％的次氯酸或其盐,使纤维素系原料氧化以制造氧化纤维素；以及对该氧化纤维素进行原纤化处理使其纳米化。(The purpose of the present invention is to provide a kind of not to be remained the N- such as TEMPO oxo-compound in cellulose nano-fibrous and be manufactured cellulose nano-fibrous method using efficient method.A kind of cellulose nano-fibrous manufacturing method comprising following steps: the hypochlorous acid or its salt for the use of effective chlorine density being 14~43 mass % make cellulose-based raw material oxidation to manufacture oxycellulose；And its nanosizing is made to oxycellulose progress fibrillation processing.)

1. a kind of cellulose nano-fibrous manufacturing method comprising following steps:

The hypochlorous acid or its salt for the use of effective chlorine density being 14~43 mass % keep cellulose-based raw material oxidation fine to manufacture oxidation Dimension element；And

Carrying out fibrillation processing to the oxycellulose makes its nanosizing.

2. cellulose nano-fibrous manufacturing method according to claim 1, wherein

The hypochlorous acid or its salt for being 18~43 mass % for effective chlorine density.

3. cellulose nano-fibrous manufacturing method according to claim 1 or 2, wherein

The hypochlorous acid or its salt are sodium hypochlorite.

[technical field]

The present invention relates to a kind of cellulose nano-fibrous manufacturing methods, after the oxidation of cellulose-based raw material, to obtaining Oxycellulose carry out fibrillation processing.More particularly it relates to a kind of cellulose nano-fibrous manufacturing method, It is characterized in that, uses the hypochlorous acid or its salt that effective chlorine density is 14~43 mass % as oxidant.

[background technique]

A kind of method is inquired into, by carrying out oxidation processes to various cellulose-based raw materials, to manufacture cellulose nanometer The cellulose nano materials such as fiber.Such as, it has been disclosed that a kind of method, 2,2,6,6- tetramethyl piperidine-N- oxygen radicals (with It is known as TEMPO down) in the presence of, it is (non-special that oxidation processes are carried out to cellulose-based raw material using the sodium hypochlorite as oxidant Sharp document 1).

Additionally it has been disclosed that a kind of manufacturing method of oxycellulose, makes in the presence of the N- oxo-compound such as TEMPO When with oxidizing cellulose-based raw materials such as sodium hypochlorite, the oxidant is gradually added into reactant by taking a certain time In system, even if the usage amount of N- oxygroup is seldom, also carboxyl efficiently can be introduced into cellulose-based raw material to (patent document 1).

Additionally it has been disclosed that a kind of method, will use the oxidants oxygen such as sodium hypochlorite in the presence of N- oxo-compound Paper pulp is aoxidized obtained from cellulose system raw material, 50 DEG C or more 120 DEG C are heated under conditions of pH3~10 hereinafter, then It is washed, thus except the N- oxo-compound (patent document 2) contained in deoxidation paper pulp as impurity.

In turn, it has been disclosed that a kind of method, without using TEMPO system in using oxidant to cellulose-based raw material into After row oxidation processes, the mechanical treatments such as further progress ultrasonication, mixer processing, so that it is few to obtain cheap and impurity Cellulose nano-fibrous (patent document 3).

[existing technical literature]

Patent document

Patent document 1: Japanese Unexamined Patent Publication 2015-67730 bulletin

Patent document 2: Japanese Unexamined Patent Publication 2010-236106 bulletin

Patent document 3: Japanese Unexamined Patent Publication 2016-30809 bulletin

Non-patent literature

Non-patent literature 1:Cellulose Commun., 14 (2), 62 (2007)

[summary of the invention]

Problems to be solved by the invention

However, the oxygen for manufacturing the N- oxo-compound such as TEMPO as catalyst in above-mentioned existing technical literature In cellulose, even if the N- oxo-compound that nitrogen quantity is about several ppm still can be remained after abundant cleaning.

Due to worrying that N- oxo-compound is toxic to environment, human body, cellulose is being prepared using oxycellulose When nanofiber aqueous dispersions, N- oxo-compound can be also mixed in the dispersion liquid, by cellulose nano-fibrous use When making high functional material, according to its purposes, N- oxo-compound present in dispersion liquid has detrimental effect.

In addition, since N- oxygroup is very expensive material, so the use of the method for N- oxygroup not being economic manufacturer Method.

It according to patent document 1, describes and is gradually added into oxidant by taking a certain time, N- oxygroup chemical combination can be reduced The usage amount of object.But due to spending the time to add oxidant, the reaction time is elongated, is not efficient manufacturing method.Into One step, due to having used N- oxo-compound in the oxidation reaction, there are a small amount of N- oxygroup is remained in oxycellulose The problem of compound.

In addition, described according to patent document 2 by heating to oxidation paper pulp obtained in oxidation reaction, N- oxo-compound can be removed.It is not efficient manufacturing method but due to needing heat treatment step, moreover, with The problem of patent document 1 is similarly, the presence of a small amount of N- oxo-compound is remained.

Further, according to patent document 3, describing can be to cellulose-based raw material using only oxidants such as hydrogen peroxide Oxidation processes are carried out, but as oxidant, it is not any greater than the aqueous sodium hypochlorite solution of 14 mass % for effective chlorine density Description or enlightenment.

In view of the foregoing, the purpose of the present invention is to provide one kind does not remain TEMPO etc. in cellulose nano-fibrous N- oxo-compound and cellulose nano-fibrous method is manufactured using the method for simple and effective.

The method used for solving the problem

The present inventor has made intensive studies in order to solve the above problems, as a result it has surprisingly been found that by using effective chlorine The hypochlorous acid or its salt that concentration is 14 mass % or more are as oxidant, even if without using N- oxo-compound conducts such as TEMPO Catalyst can also make cellulose-based raw material oxidation to manufacture oxycellulose, and it has furthermore been found that by the oxidized fibre Element, which carries out fibrillation processing, makes its nanosizing, can manufacture cellulose nano-fibrous, and completes the present invention.

That is, the first aspect of the present invention is a kind of cellulose nano-fibrous manufacturing method comprising following steps: using Effective chlorine density is the hypochlorous acid or its salt of 14~43 mass %, makes cellulose-based raw material oxidation to manufacture oxycellulose；With And its nanosizing is made to oxycellulose progress fibrillation processing.

In addition, the second aspect of the present invention is, in the cellulose nano-fibrous manufacturing method described in first aspect, make The hypochlorous acid or its salt for being 18~43 mass % with effective chlorine density.

Further, the third aspect of the present invention is, cellulose nano-fibrous described in the first aspect or second aspect Manufacturing method in, hypochlorous acid or its salt are sodium hypochlorite.

[invention effect]

The manufacturing method of the present invention does not use the N- oxo-compound as catalyst, therefore obtained cellulose nanometer N- oxo-compound, the significant worry reduced to the toxicity of environment, human body are not contained in fiber.In addition, due to without using valuableness Catalyst, that is, TEMPO compound, therefore be economically excellent manufacturing method.

[simple declaration of attached drawing]

Fig. 1, which is shown, observes cellulose nano-fibrous obtained in embodiment 1 obtain by scanning electron microscope (SEM) The photo arrived.

It is cellulose nano-fibrous obtained in embodiment 10 Fig. 2 shows being observed by scanning electron microscope (SEM) Obtained photo.

Fig. 3 is shown to be obtained by Cellulose nanocrystal obtained in scanning electron microscope (SEM) observation embodiment 7 Photo.

Fig. 4 is shown to be obtained by Cellulose nanocrystal obtained in scanning electron microscope (SEM) observation embodiment 3 Photo.

[specific embodiment]

Cellulose-based raw material in the present invention is not particularly limited, as long as the material based on cellulose, example Can such as enumerate paper pulp, native cellulose, regenerated cellulose and by cellulosic material carry out mechanical treatment and depolymerization it is micro- Fine cellulose etc..In addition, can directly be used commercially available using paper pulp as the avicel cellulose of raw material etc. as cellulose-based raw material Product.In addition, debita spissitudo can also be used in order to keep the oxidant used in the next step readily permeable into starting pulps The cellulose-based raw material of alkali process.

Cellulose nano-fibrous manufacturing method in the present invention is the following steps are included: be 14~43 using effective chlorine density The hypochlorous acid of quality % or its salt make cellulose-based raw material oxidation to manufacture oxycellulose；And to the oxycellulose into The processing of row fibrillation makes its nanosizing, wherein as the effective chlorine density in the hypochlorous acid of oxidant or its salt be preferably 16~ 43 mass %, more preferably 18~43 mass %.

In addition, effective chlorine density is more than that the hypochlorous acid of 43 mass % or its salt are easy to carry out selfdecomposition, it is difficult to handle.

Effective chlorine density in hypochlorous acid or its salt is well known concept, is defined as follows.

Hypochlorous acid is as weak acid existing for aqueous solution, and hypochlorite can be used as the presence of the solid with the crystallization water, but It, with hygroscopy, is highly unstable substance, generally as aqueous solution processing.

For example, measuring the effective chlorine in solution since the sodium hypochlorite as hypochlorite exists only in solution Content, rather than the concentration of sodium hypochlorite.

The effective chlorine of sodium hypochlorite refers to, due to the energy of oxidation for the bivalent oxygen atom that the decomposition by sodium hypochlorite generates Power is equivalent to two atom equivalents of monovalence chlorine, so the combination chlorine atom of sodium hypochlorite (NaClO) has and non-binding chlorine (Cl₂) The identical oxidability of two atoms, thus effective chlorine=2 × (chlorine in NaClO).

The measurement of specific effective chlorine density is done as follows: water, potassium iodide and acetic acid is added simultaneously in accurate weighing sample It stands, using amidin as indicator, free iodine is titrated with hypo solution to measure.

As the hypochlorous acid or its salt in the present invention, hypochloric acid water, sodium hypochlorite, postassium hypochlorite, hypochlorous acid can be enumerated Calcium and hypochlorous acid ammonium etc., wherein from the viewpoint of being easily handled, preferred sodium hypochlorite.

Hereinafter, being illustrated by taking sodium hypochlorite as an example to the manufacturing method of the present invention as hypochlorous acid or its salt.

(1) aqueous sodium hypochlorite solution for the use of effective chlorine density being 14~43 mass %, make the oxidation of cellulose-based raw material with The step of manufacturing oxycellulose.

As the method that the effective chlorine density of aqueous sodium hypochlorite solution is adjusted to 14~43 mass %, including by effective chlorine The method of aqueous sodium hypochlorite solution concentration of the concentration lower than 14 mass %, the sodium hypochlorite for being about 43 mass % by effective chlorine density Pentahydrate crystal directly using or be diluted with water the method being adjusted.Wherein, it is adjusted to using sodium hypochlorite pentahydrate As the effective chlorine density of oxidant, there is less selfdecomposition, i.e. the reduction of effective chlorine density is less, adjustment is easy, therefore It is preferred.

The usage amount for the aqueous sodium hypochlorite solution that effective chlorine density as oxidant is 14~43 mass % can promote It is selected in the range of oxidation reaction.

The mixed method of cellulose-based raw material and aqueous sodium hypochlorite solution is not particularly limited, but from the side of handling easiness Face considers, cellulose-based raw material is preferably added in aqueous sodium hypochlorite solution and is mixed.

Reaction temperature in the oxidation reaction is preferably 15~40 DEG C, and further preferably 20~35 DEG C.In order to efficient Ground carries out oxidation reaction, and the pH of reaction system is preferably maintained 7~14, further preferably maintains 10~14.In order to adjust PH can add the acid such as the alkaline agents such as sodium hydroxide, hydrochloric acid.

The reaction time of oxidation reaction can set according to the carry out degree of oxidation, still, such as preferred reaction about 15 Minute~6 hours.

In the oxidation reaction, the primary hydroxyl in cellulose-based raw material is oxidized to carboxyl, generates oxycellulose.It should The carboxyl amount of oxycellulose is not particularly limited, but in the next step, and carrying out fibrillation to oxycellulose makes its nanometer When changing to manufacture cellulose nano-fibrous, the carboxyl amount of every 1g oxycellulose is preferably 0.1~3.0mmol/g, further excellent It is selected as 0.2~1.0mmol/g.In addition, the oxidation reaction can also be divided into two stages to implement.

Carboxyl amount in oxycellulose can measure by the following method.

Pure water is added in 0.5 mass % slurry of oxycellulose, is formulated as 60ml, 0.1M aqueous hydrochloric acid solution, which is added, to be made After pH becomes 2.5,0.05N sodium hydrate aqueous solution is added dropwise, measurement conductivity is until pH reaches 11, according to the variation in conductivity Amount of sodium hydroxide (a) consumed by the neutralization stage of stable weak acid, is calculated using following formula.

Carboxyl amount (mmol/g oxycellulose)=a (ml) × 0.05/ oxycellulose quality (g)

(2) is carried out to oxycellulose the step of fibrillation processing makes its nanosizing

Cellulose nano-fibrous in the present invention is by carrying out fibril to the oxycellulose obtained in above-mentioned steps Change makes its nanosizing and manufactures.

The method of fibrillation can be limited to carry out weak stirring with blender etc. in a solvent, but can be with by mechanical fibrillation Shorten the fibrillation time.But if carrying out mechanical fibrillation, cellulose nano-fibrous possible bending or fracture.

The method of mechanical fibrillation is not particularly limited, still, such as after sufficiently cleaning oxycellulose using solvent, It can suitably be selected according to purpose, such as helical mixer, arm mixer, dispersing mixer, turbine type can be enumerated and mixed Mixer for well-distribution, high pressure homogenisers, super-high-pressure homogenization device, bicylindrical homogenizer, ultrasonic wave homogeneous under clutch, high speed rotation Device, water flow adverse current collision type dispersion machine, blender, disc type refiner, taper refiner, double plate refiner, grinder, single shaft Or mixed stirring device well known to multiaxis kneader etc., it is carried out in a solvent by the way that they combine alone or in any combination Processing, oxycellulose nanosizing can be manufactured cellulose nano-fibrous.

As solvent used in fibrillation processing, it is not particularly limited, can be suitably selected, can be enumerated according to purpose Water, alcohols, ethers, ketone, n,N-Dimethylformamide, n,N-dimethylacetamide, dimethyl sulfoxide etc. can be single by them Solely use, it can also be simultaneously using two or more.

As the alcohols, the molten fibre of methanol, ethyl alcohol, isopropanol, isobutanol, sec-butyl alcohol, the tert-butyl alcohol, methyl can be enumerated Agent, ethylene glycol and glycerol etc..

As the ethers, glycol dimethyl ether, Isosorbide-5-Nitrae-dioxane and tetrahydrofuran etc. can be enumerated.

As the ketone, acetone and methyl ethyl ketone etc. can be enumerated.

By selecting organic solvent as solvent, the oxycellulose obtained in above-mentioned steps and fibril is carried out to it Cellulose nano-fibrous separation obtained from change becomes easy.In addition, due to the fibre that can be dispersed in organic solvent Plain nanofiber is tieed up, therefore, the mixing with the resin, the resin raw material monomer that are dissolved in organic solvent etc. becomes easy.

Cellulose nano-fibrous manufacturing method of the invention is also applied for Cellulose nanocrystal, manufacture through the invention Cellulose nano-fibrous and Cellulose nanocrystal the width of method manufacture is preferably 2~100nm, in the range, barrier Property, the transparency and heat resistance are especially excellent.

Cellulose nano-fibrous fibre length is not particularly limited, but preferably 10~1000 μm, more preferably 100~ 500 μm, aspect ratio (fibre length/fibre diameter) is 1000~15000, preferably from about 2000~10000.

The fibre length of Cellulose nanocrystal is about 100~1000nm (preferably 150~500nm).In addition, cellulose is received Rice is brilliant to be also referred to as Cellulose nanocrystal palpus.