JP6591304B2 - Easily dispersible cellulose composition, method for producing easily dispersible cellulose composition, cellulose dispersed resin composition, and method for producing cellulose dispersed resin composition - Google Patents

Description

  Although the present invention has attracted attention as an excellent filler function, it is a hydrophilic substance and has a strong hydrogen bond in its structure. Therefore, it is difficult to disperse in a polyolefin such as a hydrophobic resin. At present, the present invention relates to a new technology that makes it possible to realize wide use of fine cellulose fibers whose use is not promoted. Specifically, by using a polyolefin emulsion dispersed in water in nano size, the nano resin dispersed in water was treated with the polyolefin to increase the resin dispersibility of cellulose difficult to disperse, The present invention relates to a technique for providing an easily dispersible cellulose composition and providing a cellulose-dispersed resin composition using the same.

Cellulose fiber is a basic skeletal material of all plants, has accumulated over a trillion tons on the earth, and is a resource that can be regenerated by tree planting, so its effective use is desired. Cellulose fibers are fibers that are 5 times stronger than steel and have a low linear thermal expansion coefficient that is 1/50 that of glass, despite being 1/5 lighter than steel. For this reason, there is a technique in which cellulose fibers are contained as a filler in a matrix such as a resin to impart mechanical strength (Patent Document 1). In addition, for the purpose of further improving the mechanical strength of cellulose fibers, cellulose nanofibers (which may be abbreviated as “microfibrillated plant fibers” or “CNF”) obtained by defibrating cellulose fibers have been manufactured (Patent Document 2). ). Similar to CNF, cellulose nanocrystals (sometimes abbreviated as CNC) are known as fibrillated cellulose fibers. CNF is a fiber obtained by subjecting cellulose fibers to treatment such as mechanical defibration, and is a fiber having a fiber width of about 4 to 100 nm and a fiber length of about 5 μm or more. CNC is a crystal obtained by subjecting cellulose fibers to chemical treatment such as acid hydrolysis, and is a crystal having a crystal width of about 10 to 50 nm and a crystal length of about 500 nm. These CNF and CNC are collectively referred to as nanocellulose. Nanocellulose has a high specific surface area (250 to 300 m ² / g), is lighter and has higher strength than steel.

  Nanocellulose is less thermally deformed than glass. Nanocellulose having high strength and low thermal expansion is a useful material as a sustainable resource material. For example, composite materials that combine nanocellulose and polymer materials such as resins to achieve high strength and low thermal expansion, airgel materials, optically anisotropic materials using chiral nematic liquid crystal phases by CNC self-assembly, nanocellulose Development and creation have been made such that functional functional groups are introduced into a highly functional material. On the other hand, since nanocellulose has abundant hydroxyl groups, it has an aspect that is inferior in compatibility with a versatile resin having hydrophilicity and strong polarity, and hydrophobicity and no polarity. For this reason, in the development of materials using nanocellulose, it is considered to improve the compatibility of nanocellulose with general-purpose resins by modifying the surface of nanocellulose or introducing functional groups into nanocellulose by chemical treatment. ing. That is, various studies have been made to improve the dispersibility of nanocellulose, which is a useful material, for general-purpose resins.

  Further, in the production of a versatile resin composition containing cellulose fiber as a filler, it has been studied to add a dispersant to improve the dispersibility and compatibility between the cellulose fiber and the universal resin. For example, in Non-Patent Document 1, the organic solvent dispersibility of cellulose nanocrystals is improved by adsorbing a surfactant to cellulose nanocrystals (cellulose nanowhiskers). In Non-Patent Document 2, an isotactic polypropylene (iPP) composite material using cellulose nanocrystals adsorbed with a surfactant as a reinforcing material is produced, and the tensile strength is improved by about 1.4 times compared to iPP alone. Yes. Further, in Patent Document 2, when cellulose is used as a reinforcing material for thermoplastic resin, it is hydrophilic and specified with cellulose fiber for the purpose of suppressing the generation of cellulose agglomerates and uniformly dispersing cellulose in the resin. It has been proposed to disperse an additive (low molecular weight surfactant) having an HLB value (hydrophilic / lipophilic balance).

JP 2008-266630 A International Publication No. 2012/111408

Heux et al., Langmuir, Vol. 16, no. 21, 2000, 8210-8212 Ljungberg et al., Polymer, Vol. 47, 2006, 6285-6292

  As described above, various methods are used to add cellulose to the resin and finely disperse it in the resin as a cellulose nanostructure, which improves the strength of the resin. It was hard to say that it was excellent. First, as resins for finely dispersing cellulose, polyolefins such as polyethylene and polypropylene, which are polyalkenes, are widely used. However, since these resins are highly hydrophobic and low in polarity, cellulose that is a hydrophilic substance is sufficiently used. In some cases, it was not possible to obtain a good dispersion state by dispersion. In addition, in order to introduce a functional functional group into nanocellulose to form a functional group, it is necessary to take multiple steps, and this method has a problem that it is complicated. In addition, in the method of adding a dispersant, it is considered that various types such as acrylic polymers, ester polymers, and urethane polymers that are conventionally used as pigment dispersants can be used. It may not be compatible with polyolefin and may not be applied. Also, a dispersing agent may be separately designed, or a mixing step of the dispersing agent and cellulose is required. There were cases where it could not be demonstrated.

  The present invention has been made in view of the background of the prior art, and its purpose is to perform the surface modification of nanocellulose and the introduction of functional groups into nanocellulose as in the prior art, To provide a technology for making cellulose materials applicable to general-purpose resins by easily dispersing cellulose, which is a hydrophilic substance, into a highly hydrophobic polyolefin by a simple method. is there. Another object of the present invention is to easily disperse cellulose in a hydrophobic material such as a general-purpose resin by simply and efficiently treating cellulose in a system using water as a main medium. It is another object of the present invention to provide a functional cellulose composition and to thereby provide a useful cellulose-dispersed resin composition.

  As a result of intensive studies to solve the problems of the prior art described above, the present inventors have found that an alkali neutralized emulsion of polyolefin, which is a polyalkene having a carboxy group, in an aqueous solution of cellulose nanofiber finely dispersed in water. Can be made into an easily dispersible cellulose composition by confining cellulose in the precipitated olefin in a state where cellulose nanofibers are dispersed in a state where the olefin is precipitated by neutralizing with an acid. As a result, the present invention has been achieved. That is, by using the easily dispersible cellulose composition configured as described above, when cellulose is dispersed in a resin, a good cellulose-dispersed resin composition can be obtained while suppressing the generation of cellulose aggregates. I found it. In the present invention, unless otherwise specified, polyolefin refers to polyalkene and may be simply referred to as polyolefin.

  The above object is achieved by the present invention described below. That is, the present invention is an easily dispersible cellulose composition having improved dispersibility of cellulose in a resin, which is composed of cellulose and polyolefin, wherein the cellulose is cellulose nanofiber, cellulose nanocrystal, pulp, lignocellulose. And at least one cellulose fiber selected from the group consisting of wood flour, the polyolefin is a polyalkene, has a carboxy group, its acid value is 50 mg KOH / g or less, and its melting point is 80 ° C. or higher. And providing an easily dispersible cellulose composition comprising 5% to 30% of the cellulose on a mass basis.

  A preferable form of the easily dispersible cellulose composition of the present invention is that the carboxy group of the polyolefin reacts with the hydroxyl group of the cellulose to form an ester bond.

  As another embodiment, the present invention provides a method for producing a readily dispersible cellulose composition having improved dispersibility of cellulose in a resin, and a polyolefin emulsion of polyolefin, which is a polyalkene having a carboxy group, in a water-containing state or a dried state. And then mixing the cellulose with a cellulose emulsion to obtain a mixed aqueous solution of cellulose and a polyolefin emulsion, and then adding an acid to precipitate the polyolefin. The polyolefin emulsion used in the step has an acid value of 50 mgKOH / g or less. A polyolefin emulsion having a melting point of 80 ° C. or more, neutralized with an alkali and emulsified in water, and having an average particle size of 300 nm or less by a particle size measuring instrument based on light scattering. A method for producing an easily dispersible cellulose composition is provided. That.

  The following are mentioned as a preferable form of the manufacturing method of the easily dispersible cellulose composition of this invention. That is, the cellulose is at least one cellulose fiber selected from the group consisting of cellulose nanofibers, cellulose nanocrystals, pulp, lignocellulose, and wood flour; the content of cellulose in the mixed aqueous solution is based on mass 3% or less; the mixed aqueous solution contains the polyolefin in a range of 233.3 parts to 1900 parts with respect to 100 parts of the cellulose on a mass basis; after the step of depositing the polyolefin And a step of heating at a temperature of 90 ° C. or higher, and in the heating step, the carboxy group of the polyolefin is reacted with the hydroxyl group of the cellulose to perform dehydration condensation to form an ester bond. It is done.

  Another embodiment of the present invention is a cellulose-dispersed resin composition that is a mixture of cellulose and a resin, wherein the cellulose has a highly dispersible cellulose composition in which the dispersibility of the cellulose in the resin is increased. And a cellulose-dispersed resin composition comprising 0.1% to 10% of cellulose on a mass basis in the composition.

  As a preferable form of the cellulose-dispersed resin composition of the present invention, it is mentioned that the resin is a polyolefin that is a polyalkene and a polymer having the same skeleton as the polyolefin constituting the easily dispersible cellulose composition.

  Another embodiment of the present invention is a production method for obtaining a cellulose-dispersed resin composition, which is a mixture of cellulose and resin, and is a polyalkene having a carboxy group, the acid value of which is 50 mgKOH / g or less. A polyolefin emulsion obtained by neutralizing polyolefin with an alkali is mixed with water-containing or dried cellulose to obtain a mixed aqueous solution of cellulose and polyolefin emulsion, and then an acid is added to precipitate the polyolefin. A cellulose-dispersed resin composition is obtained by using a readily dispersible cellulose composition having improved dispersibility in the resin and mixing with the resin while containing a liquid component resulting from the production of the easily dispersible cellulose composition. A method for producing a cellulose-dispersed resin composition is provided.

  As a preferred form of the method for producing a cellulose-dispersed resin composition of the present invention, the above-mentioned polyolefin emulsion is obtained by neutralizing a polyolefin having a melting point of 80 ° C. or higher with an alkali and emulsifying it in water. It is mentioned that it is a polyolefin emulsion whose average particle diameter by a diameter measuring machine is 300 nm or less.

  According to the present invention, a simple method is effective for obtaining a cellulose-dispersed resin composition in which cellulose, which is a hydrophilic substance, is dispersed in a good state in a highly hydrophobic and low-polarity resin. Dispersible cellulose compositions are provided. According to the present invention, it is a natural material that can be regenerated, and although its function as an excellent filler has attracted attention, it is a hydrophilic substance, so it is difficult to disperse in a resin or the like. In the present invention, cellulose is applied to the resin by adding and dispersing the cellulose in the resin by using a complicated chemically modified cellulose or by using a separately prepared dispersant. Since an effective easily dispersible cellulose composition is obtained by the method, it is possible to realize a wide range of utilization of fine cellulose fibers which are useful materials but have not been promoted.

  More specifically, in the present invention, it is possible to provide a useful easily dispersible cellulose composition by the following simple method. Cellulose nanofibers using polyolefin emulsion which has a mechanical strength and can be used as plastic, polyolefins with minimal carboxy group of acidic group which is different functional group are dispersed in nanoparticles By treating this, cellulose easily disperses in the polyolefin resin that is a polyalkene, and becomes easily dispersible cellulose with improved dispersibility in the resin. Therefore, a cellulose-dispersed resin composition obtained using this, The performance derived from nanocellulose is exhibited, and high strength can be exhibited. As described above, a major technical feature of the present invention is that a polyolefin emulsion having an extremely low acid value, an alkali of the acid, and nano-particle dispersion is used.

It is a figure which shows the dispersibility test result to a thermal xylene about each composition containing the cellulose of Example 2, Example 5, and the comparative example 2. FIG. It is a figure which shows that the film | membrane which consists of the easily dispersible cellulose composition CP-6 of Example 7 is a slightly translucent film | membrane which can visually recognize the pattern of a foundation | substrate clearly. It is a figure of the electron micrograph of the film | membrane which consists of the easily dispersible cellulose composition CP-6 of Example 7. FIG.

  The present invention will be described in more detail with reference to the best mode for carrying out the invention. The easily dispersible cellulose composition of the present invention is a mixture of polyolefin and cellulose having a very low acid value and a high Tg. More specifically, the polyolefin is a polyalkene, has a carboxy group as an acid group, has an acid value of 50 mg KOH / g or less, has a melting point of 80 ° C. or more, and cellulose is cellulose nanofiber. It is at least 1 sort (s) of cellulose fiber chosen from the group which consists of a cellulose nanocrystal, a pulp, lignocellulose, and a wood flour, This cellulose is characterized by containing 5-30% on a mass basis. The easily dispersible cellulose composition of the present invention having the above configuration can be easily obtained by the following production method of the present invention.

  In the method for producing an easily dispersible cellulose composition of the present invention, a polyolefin emulsion of polyolefin which is a polyalkene having a carboxy group is mixed with cellulose in a water-containing state or in a dry state to obtain a mixed aqueous solution of cellulose and polyolefin emulsion. The polyolefin emulsion used in this step neutralizes the polyolefin having an acid value of 50 mgKOH / g or less and a melting point of 80 ° C. or more with an alkali. And a polyolefin emulsion having an average particle diameter of 300 nm or less measured by a particle diameter measuring device by light scattering. That is, in the production method of the present invention, the polyolefin used for making cellulose easily dispersible has an acid group of carboxy group, and the carboxy group is neutralized with an alkali. It is used as an emulsion of polyolefin dispersed and emulsified in the form of nanoparticles. This polyolefin emulsion is mixed with water-containing or dry cellulose and, for example, CNF dispersed in water to obtain a mixed aqueous solution of CNF and polyolefin emulsion, and then neutralized and ionized. The carboxylic acid is returned to the carboxylic acid by addition of acid and precipitated. By doing in this way, cellulose, such as CNF, can be wrapped with polyolefin in the state disperse | distributed in the liquid. The composition composed of cellulose and resin thus obtained can be kneaded or melt-mixed or dispersed in another resin, preferably a polyolefin resin, so that cellulose such as CNF can be easily dispersed in the resin. It becomes possible. That is, the composition obtained by the above-described production method becomes a cellulose composition exhibiting easy dispersibility with improved dispersibility of cellulose in an olefin resin.

  As described above, a cellulose-dispersed resin composition can be obtained very easily by complexing with a resin using the easily dispersible cellulose composition of the present invention obtained by the production method of the present invention. it can. According to the study by the present inventors, the obtained cellulose-dispersed resin composition has a cellulose dispersed well in the resin, and further has improved mechanical strength when injection molded. Thus, according to the present invention, an easily dispersible cellulose composition having excellent compatibility with a resin can be obtained by an extremely simple method. By using this, cellulose that is an excellent material as a functional material can be obtained. Is expected to be widely used.

  Hereinafter, the easily dispersible cellulose composition of the present invention will be described. The easily dispersible cellulose composition of the present invention is an easily dispersible cellulose composition comprising cellulose and polyolefin and having improved dispersibility of cellulose in a resin. Hereinafter, these will be described.

(cellulose)
The cellulose used in the present invention is at least one selected from the group consisting of cellulose nanofiber (CNF), cellulose nanocrystal (CNC), pulp, lignocellulose and wood flour, for example. In particular, it is preferable to use CNF or CNC. In the present invention, CNF and CNC are also referred to as “nanocellulose”. Hereinafter, each cellulose will be described in detail. In addition, as a typical example of cellulose, the present invention may be described using “nanocellulose” or CNF, but the present invention is not limited to these.

  Plant fiber used as a raw material for cellulose (or cellulose fiber) is recycled from natural plant materials such as wood, bamboo, hemp, jute, kenaf, cotton, beet, agricultural waste and cloth, and recycled pulp, rayon, cellophane, etc. A cellulose fiber etc. are mentioned. Examples of the wood include Sitka spruce, cedar, cypress, eucalyptus, and acacia. Examples of the paper include deinked waste paper, corrugated paper, magazines, and copy paper. However, it is not limited to these. One kind of plant fiber may be used alone, or two or more kinds selected from these may be used.

  Lignocellulose is the main component of plant fibers, and is mainly composed of cellulose, hemicellulose, and lignin, and has a structure in which each is bound to form plant fibers. Pulp is obtained by removing hemicellulose and lignin from the plant fiber containing lignocellulose by mechanical treatment and / or chemical treatment to increase the pure content of cellulose. A bleaching treatment is also performed as necessary, and the amount of delignification can be adjusted to adjust the amount of lignin in the pulp.

  As the pulp, chemical pulp [craft pulp (KP), sulfite pulp (SP)], semi-chemical pulp (SCP), chemiground pulp (obtained by pulping plant fibers by mechanical treatment and / or chemical treatment) CGP), chemimechanical pulp (CMP), groundwood pulp (GP), refiner mechanical pulp (RMP), thermomechanical pulp (TWP), chemithermomechanical pulp (CTMP), and deinked waste paper based on these pulps Pulp, cardboard waste paper pulp, magazine waste paper pulp and the like are preferred. Among these pulps, various kraft pulps derived from conifers with strong fiber strength [unleaved kraft pulps of conifers (NUKP), unbleached kraft pulps exposed to oxygen of conifers (NOKP), and bleached kraft pulps of conifers (NBKP)] are particularly preferable. The lignin content in the pulp is not particularly limited, but is usually about 0 to 40% by mass, preferably about 0 to 10% by mass. The lignin content can be measured by the Klason method.

  Nanocellulose that can be suitably used in the present invention is cellulose in which a material containing cellulose fibers (for example, wood pulp or the like) has been unraveled (defibrated) to a nanosize level, and includes CNF and CNC. In the plant cell wall, cellulose microfibrils (single cellulose nanofibers) with a width of about 4 nm exist as a minimum unit and are the basic skeletal material of plants. Nanocellulose is composed of multiple cellulose microfibrils or cellulose microfibrils. It is a nano-sized cellulose formed as described above.

Among the nanocelluloses, CNF is a fiber obtained by subjecting cellulose fibers to treatment such as mechanical defibration, and is a fiber having a fiber width of about 4 to 200 nm and a fiber length of about 5 μm or more. The specific surface area of the CNF for use in the present invention, preferably about 70~300m ² / g, more preferably about 70 to 250 ² / g, about 100 to 200 m ² / g is more preferable. By increasing the specific surface area of CNF, when the resin composition is combined with a resin, the contact area can be increased and the strength is improved. On the other hand, if the specific surface area is extremely high, aggregation of the resin composition in the resin tends to occur, and the intended high-strength material may not be obtained. The average fiber diameter of CNF used in the present invention is usually about 4 to 200 nm, preferably about 4 to 150 nm, and particularly preferably about 4 to 100 nm.

  Examples of a method for defibrating plant fibers and preparing CNF include a method for defibrating cellulose fiber-containing materials such as pulp. As the defibrating method, for example, an aqueous suspension or slurry of a cellulose fiber-containing material is mechanically processed by a refiner, a high-pressure homogenizer, a grinder, a uniaxial or multiaxial kneader (preferably a biaxial kneader), a bead mill or the like. A method of defibration by grinding or beating can be used. You may process combining the said defibrating method as needed. As these defibrating methods, for example, the defibrating methods described in JP2011-213754A and JP2011-195738A can be used.

CNC suitable as cellulose used in the present invention is a crystal obtained by subjecting cellulose fibers to chemical treatment such as acid hydrolysis, and is a crystal having a crystal width of about 4 to 70 nm and a crystal length of about 25 to 3000 nm. The specific surface area of the CNC for use in the present invention, preferably about 90~900m ² / g, more preferably about 100 to 500 m ² / g, about 100 to 300 m ² / g is more preferable. By increasing the specific surface area of the CNC, when the resin composition is combined with the resin, the contact area can be increased and the strength is improved. On the other hand, if the specific surface area is extremely high, aggregation of the resin composition in the resin tends to occur, and the intended high-strength material may not be obtained. The average crystal width of the CNC crystal used in the present invention is usually about 10 to 50 nm, preferably about 10 to 30 nm, and particularly preferably about 10 to 20 nm. The average crystal length of the CNC is usually about 500 nm, preferably about 100 to 500 nm, particularly preferably about 100 to 200 nm.

  A conventionally known method can be adopted as a method of defibrillating plant fibers and preparing CNC. For example, a chemical method such as acid hydrolysis of the aqueous suspension or slurry of the cellulose fiber-containing material with sulfuric acid, hydrochloric acid, hydrobromic acid or the like can be used. You may process combining the said defibrating method as needed. In the present invention, it is preferable to use the functional group of cellulose as it is. However, in some cases, the surface of cellulose is chemically modified with tetramethylpiperidinyloxy radical, acid anhydride, or acid halide to improve dispersibility. Enhanced cellulose may be used.

  The average value of the fiber diameter of nanocellulose in the present invention (average fiber diameter, average fiber length, average crystal width, average crystal length) is an average value when measuring at least 50 nanocelluloses in the field of view of an electron microscope. It is.

Nanocellulose has a high specific surface area (preferably about 200 to 300 m ² / g), is lighter and has higher strength than steel. Nanocellulose also has low thermal deformation (low thermal expansion) compared to glass.

  The nanocellulose used in the present invention preferably has a cellulose I-type crystal structure and a crystallinity as high as 50% or more. The crystallinity of the cellulose I-type crystal structure of nanocellulose is more preferably 55% or more, and still more preferably 60% or more. The upper limit of the crystallinity of the cellulose I type crystal structure of nanocellulose is generally about 95% or about 90%.

  The cellulose type I crystal structure is, for example, as described in “A Dictionary of Cellulose”, First Edition, pages 81-86 or 93-99, published by Asakura Shoten. Most natural celluloses are cellulose I Type crystal structure. On the other hand, for example, cellulose fibers having a cellulose II, III, and IV structure, not a cellulose I type crystal structure, are derived from cellulose having a cellulose I type crystal structure. Above all, the I-type crystal structure has a higher crystal elastic modulus than other structures.

  Among the celluloses used in the present invention, nanocellulose having a cellulose I-type crystal structure is preferable. In the case of the I-type crystal structure, a composite material having a low linear expansion coefficient and a high elastic modulus can be obtained when a composite material of nanocellulose and a matrix resin is used. The fact that nanocellulose has a type I crystal structure is typical at two positions near 2θ = 14 ° to 17 ° and 2θ = 22 to 23 ° in the diffraction profile obtained by wide-angle X-ray diffraction image measurement. It can be identified from having a large peak.

The crystallinity of the cellulose type I crystal structure can be measured, for example, as follows. First, ethanol is added to a slurry of nanocellulose such as CNF to adjust the nanocellulose concentration to 0.5% by mass. Next, after the slurry is stirred with a stirrer, vacuum filtration (5C filter paper manufactured by Advantech Toyo Co., Ltd.) is quickly started. Next, the obtained wet web is heated and compressed at 110 ° C. and a pressure of 0.1 t for 10 minutes to obtain a CNF sheet of 50 g / m ² . Then, using an X-ray generator (“UltraX18HF” manufactured by Rigaku Corporation), the target Cu / Kα ray, voltage 40 kV, current 300 mA, scanning angle (2θ) 5.0-40.0 °, step angle 0.02 ° Under the measurement conditions, the CNF sheet obtained above is measured, and the crystallinity of the cellulose I-type crystal structure is measured.

  Here, the degree of polymerization of cellulose is about 500 to 10,000 for natural cellulose and about 200 to 800 for regenerated cellulose. Cellulose is a bundle of several celluloses that are linearly stretched by β-1,4 bonds, which are fixed by hydrogen bonds within or between molecules to form crystals that are elongated chains. . The fact that many crystal forms exist in the crystal of cellulose has been clarified by analysis by X-ray diffraction or solid state NMR, but the crystal form of natural cellulose is only the I type. From the X-ray diffraction etc., it is estimated that the ratio of the crystal region in cellulose is about 50 to 60% for wood pulp and higher for bacterial cellulose, about 70%. Due to the fact that cellulose is an extended chain crystal, cellulose not only has a high elastic modulus, but also exhibits a strength five times that of steel and a linear thermal expansion coefficient of 1/50 or less that of glass. Conversely, breaking the crystal structure of cellulose leads to the loss of excellent characteristics such as high elastic modulus and high strength of cellulose.

  The cellulose composition of the present invention comprising a polyolefin having a Karhogishi group and the cellulose as described above breaks the cellulose crystal by the above-described simple production method of the present invention for precipitating a polyolefin emulsion having a specific structure. Therefore, it becomes an easily dispersible cellulose composition that is well dispersed in the resin by the polyolefin. In the present invention, a cellulose-dispersed resin composition in which cellulose is well dispersed in the resin without breaking the above-described cellulose crystals by using the easily dispersible cellulose composition and combining with the resin. You can get things. According to the present invention, in the resin, the cellulose crystals are present in an unbroken state, and the cellulose has excellent dispersibility, so that an excellent machine such as high elastic modulus and high strength of cellulose in the resin. The characteristics are exhibited, and as a result, a high elastic modulus and high strength resin composition can be obtained.

(Polyolefin)
The polyolefin used in the present invention is a polyalkene having a carboxy group in its structure, an acid value of 50 mgKOH / g or less, and a melting point of the polyolefin of 80 ° C. or more. To do. First, as the polyolefin polymer, conventionally known polymers are used and there is no particular limitation. Specifically, polyethylene, polypropylene, poly 1-butene, poly 1-pentene, poly (3-methyl-1-butene), poly 1-hexene, poly (3-methyl-1-pentene), poly (4 -Methyl-1-pentene), poly (1-heptene), poly (4-methyl-1-hexene), poly (5-methyl-1-hexene), poly (1-octene), poly (5-methyl- 1-heptene) homopolymers (excluding single polymers except Tg of less than 80 ° C.), copolymer polymers, graft copolymers and graft copolymers obtained by polymerizing two or more of the monomers in the monomer units of these polymers The polymer has a higher-order structure such as a linear or branched structure, and any molecular weight, arrangement, crystallinity, etc. are used. Moreover, the synthesis method etc. are not specifically limited.

  The polyolefin used in the present invention needs to have a minimum acidic group that allows the polyolefin to be finely dispersed in water. Further, the acidic group has at least a carboxy group, and its acid value. Of 50 mgKOH / g or less. The acid value can be determined by the following method. That is, it is obtained by dissolving the polyolefin to be measured in a polyolefin soluble solvent such as xylene or octane and titrating with a 0.1 N potassium hydroxide ethanol solution using a phenolphthalein solution as an indicator. . The acid value is expressed in mg of potassium hydroxide necessary to neutralize 1 g of resin. The carboxy group possessed by the polyolefin is required to have a small amount of acid value that can be neutralized with an alkali and finely dispersed in water, and specifically, the acid value must be 50 mgKOH / g or less. . According to the study by the present inventors, when the acid value of the polyolefin used in the present invention is more than 50 mgKOH / g, there are many acidic groups. May be inferior or not water resistant. More preferably, it is 30 mgKOH / g or less, More preferably, it is 15 mgKOH / g.

  This carboxy group is obtained by copolymerizing a monomer having a carboxy group that can be copolymerized with an alkane, for example, copolymerizing styrene carboxylic acid, acrylic acid, maleic anhydride, methacrylic acid, etc. After polymerization, a carboxy group may be introduced by hydrolysis or the like. Further, a polyolefin having a carboxy group, acrylic acid, maleic anhydride, and maleic acid may be introduced into a side chain and grafted using a peroxide or the like to a polyolefin obtained in advance.

  In the production method of the present invention, a polyolefin emulsion obtained by neutralizing the carboxy group of these polyolefins with an alkali and dispersing them in water is used. The average particle size of the polyolefin emulsion used in the production method of the present invention by a particle size measuring device by light scattering is 300 nm or less. Examples of polyolefin emulsions include those that are forcibly emulsified using a surfactant, those that are emulsified by introducing a large amount of carboxy groups, for example, 100 mg KOH / g or more, and those that are emulsified in large amounts. Some of them are introduced and used to emulsify and disperse polyolefin. However, in the case of these emulsions, there are many carboxy groups, so when used in a resin composition, the water resistance is poor or the physical properties are inferior, and when the emulsion is made using a surfactant In some cases, the surfactant may remain and adversely affect the article made of the resin composition. Therefore, in the production method of the present invention, a polyolefin emulsion having the above carboxy group content, an acid value of 50 mgKOH / g or less, and an average particle size of 300 nm or less is used.

  The method for obtaining the polyolefin emulsion having the average particle size used in the present invention is not particularly limited. For example, melt a polyolefin having a carboxy group and neutralize with alkali, gradually add water, dissolve a polyolefin having a carboxy group in an organic solvent, and mix with alkaline water to make an aqueous solution. Then, the organic solvent can be used as it is or by distilling it off to form an emulsion. The organic solvent used above is not particularly limited, but in the case of an organic solvent-containing emulsion as it is, it is preferable to use a water-soluble organic solvent, such as alcohols, glycols, amines, amides, etc. A hydrophilic solvent may be included. Examples of alcohols that can be used include methanol, ethanol, propanol, and butanol. Examples of glycols include ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol methyl ether, propylene glycol methyl ether, propylene glycol propyl ether, and diethylene glycol. Methyl ether, diethylene glycol butyl ether, diethylene glycol dimethyl ether, etc. can be used, and as amines, for example, methylamine, ethylamine, propylamine, butylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, ethylenediamine, diethylenetriamine can be used, and amides For example, dimethylformamide Dimethylacetamide, pyrrolidone, methyl pyrrolidone, ethyl pyrrolidone can be used.

  In the method for producing an easily dispersible cellulose composition of the present invention, the average particle size of the polyolefin emulsion to be used is important, and one having a particle size of 300 nm or less, more preferably 250 nm or less is used. According to the study by the present inventors, it was possible to obtain an easily dispersible cellulose exhibiting good dispersion by using an emulsion having such an average particle diameter. Although the influence of the particle size of this polyolefin emulsion is unclear, it has been confirmed that there is the following tendency. First, if the average particle size is large, when polyolefin is precipitated with an acid, the polyolefin is deposited in spots on CNF, resulting in an uncoated CNF portion, which again becomes a hard bond and inhibits dispersion. There was a case. On the other hand, if the particle size is small, polyolefin precipitates uniformly in CNF by precipitation with acid, prevents hydrogen bonding between CNFs, and is confined in polyolefin in a state where CNF is dispersed. As a result, resin addition Thus, it is considered that CNF could be dispersed in the resin simply by kneading. According to the study by the present inventors, in order to achieve an average particle diameter of 300 nm or less without requiring a carboxy group or a surfactant, it is necessary to set the acid value as described above.

  The easily dispersible cellulose composition of the present invention can be easily obtained by using cellulose and polyolefin as described above. The content of cellulose in the composition is 5% to 30%, more preferably 5% to 20%, based on mass. If the amount of cellulose constituting is less than 5%, the amount of polyolefin constituting the relatively easily dispersible cellulose composition will increase. Therefore, it is added to a resin that is plastic, and CNF is added as a cellulose-dispersed resin composition. Even if it is going to show the characteristic of this, the property of the used polyolefin will come out and it is not preferable. On the other hand, if the amount of cellulose to be formed is more than 30%, a part that is not covered with polyolefin or cellulose comes out, and the part that is not covered is hydrogen-bonded with cellulose, and is a plastic that is a base material to be dispersed. In some cases, the resin does not disperse well.

(Manufacturing method of easily dispersible cellulose composition)
The easily dispersible cellulose composition of the present invention described above can be easily obtained by the following production method of the present invention. That is, this invention provides the manufacturing method of the easily dispersible cellulose composition which improved the dispersibility of the above-mentioned cellulose in resin. Specifically, the easily dispersible cellulose composition of the present invention is a polyolefin, which is a polyalkene having a carboxy group, neutralized with an alkali and emulsified in water, and has an acid value of 50 mgKOH / g or less. A polyolefin emulsion in which an average particle diameter by a particle diameter measuring instrument by light scattering is 300 nm or less and a melting point of the polyolefin is 80 ° C. or more is mixed with cellulose in a water-containing state or in a dry state, and cellulose and polyolefin emulsion Is obtained by adding an acid to precipitate the polyolefin. Preferably, the cellulose content in the mixed aqueous solution of cellulose and polyolefin emulsion is 3% or less on a mass basis, and more preferably, the cellulose is added to 100 parts of the cellulose so that the cellulose content becomes such. It is preferable to prepare a mixed aqueous solution of cellulose and a polyolefin emulsion with 233.3 parts to 1900 parts of polyolefin.

  In the production method of the present invention, as described above, cellulose is fibrillated by various methods and used as cellulose nanofibers. Disperse this in water. In this case, CNF has high hydrophilicity and is nano-sized, so that the viscosity becomes high or it has been defibrated, but CNFs aggregate again due to hydrogen bonding, and the nano-size is lost. When CNF is encapsulated and encapsulated with polyolefin by precipitation with an acid, there is a possibility that CNF may be closely aggregated. Therefore, the concentration of CNF in the aqueous solution should be low, preferably 3% or less, more preferably 1% or less. If it exceeds 3%, the concentration is too high and the above disadvantages may occur, which is not preferable. Further, if necessary, the aforementioned water-soluble organic solvent may be used in order to reduce the viscosity or increase the affinity of cellulose for water. The amount is arbitrary, and it is used in combination with water as long as the cellulose concentration is as described above. The pH at this time is preferably neutral to alkaline. If it is acidic, the polyolefin may precipitate when the polyolefin emulsion is added.

  Next, the polyolefin emulsion used in the production method of the present invention will be described. As described above, in the production method of the present invention, a polyolefin emulsion having at least a carboxyl group which is an acidic group having a content as small as possible, and having the acidic group neutralized with an alkali and dispersed in fine particles of 300 nm or less. Is used. The polyolefin has been described above. The acidic group is required to be a carboxylic acid group (carboxy group). According to the study by the present inventors, when the acidic group is a sulfonic acid group or a phosphoric acid group, the acidity is strong. Therefore, the obtained easily dispersible cellulose composition is applied to a resin to form a resin composition. In such a case, the water resistance may be inferior or the physical properties of the substrate may be deteriorated.

  Moreover, the alkali used for neutralization of an acidic group is arbitrary, and is not specifically limited. Illustratively, ammonia; organic amines such as triethylamine, diethanolamine, dimethylaminoethanol, and aminomethylpropanol; one or more hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide are used. These alkalis are used in part or in an equimolar amount or in excess of the carboxylic acid used in the polymer, and are not particularly limited. These alkalis neutralize and ionize the carboxy group to form an emulsion. The concentration of the polymer contained in the emulsion is arbitrary and is not particularly limited. Further, as described above, the emulsion may contain other water-soluble solvent.

  In the production method of the present invention, the cellulose described above and a polyolefin emulsion are used. As described above, since the easily dispersible nanocellulose fiber composition of the present invention needs to contain 5% to 30% of cellulose on a mass basis, the polyolefin is used so that the content of CNF is in this range. And polyolefin emulsions for it are used. Specifically, on a mass basis, polyolefin is 233.3 parts to 1900 parts with respect to 100 parts of CNF, and is manufactured by using this blend. The amount of CNF in the container is sufficiently defibrated and dispersed while stirring, and the polyolefin emulsion is added and homogenized well. In this homogenization, conventionally known stirring devices and dispersers are used, and are not particularly limited. For example, the mixture may be mixed and stirred with a stirrer, a stirrer with a motor, a high-speed dissolver, or a homomixer, or may be dispersed again and mixed with a dispersing machine such as a bead mill or a high-pressure homogenizer. Moreover, you may add the above-mentioned water-soluble organic solvent in the case of homogenization as needed.

  Next, in the production method of the present invention, an acid is added to the mixed aqueous solution of cellulose and olefin obtained above while stirring to deionize the ionized carboxy group of the polyolefin to make the polyolefin water insoluble. To precipitate. By doing in this way, the disperse | distributed cellulose is included and wrapped with polyolefin, and it is set as the easily dispersible cellulose composition of this invention. Any acid can be used as the acid, and is not particularly limited. Specifically, one or more inorganic acids such as hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid and phosphoric acid, and organic acids such as acetic acid and lactic acid are used. Moreover, when adding an acid, although an acid may be added with a undiluted | stock solution, it is preferable to dilute with water and to add. If the concentration is high, precipitation may occur locally and the shape may become dumpling. A preferable acid concentration is 10% by mass or less. The acid may be added at once, may be added dropwise, or may be sprayed. Also. After adding the acid, it is preferable to add the acid so that the mixed aqueous solution becomes sufficiently acidic. Specifically, the pH of the mixed aqueous solution is 4 or less, preferably 3 or less. By adding this acid, the polyolefin can be deposited and included in a dispersed state of cellulose.

  After the polyolefin is precipitated, it is filtered and washed. Prior to filtration, in order to speed up filterability, it is preferable to heat the aqueous solution to aggregate the precipitates. The temperature is not particularly limited and is arbitrary. After filtration, it is preferable to wash and remove ions and organic substances to obtain a water paste of easily dispersible cellulose nanofibers. The water paste thus obtained may be used as it is, or is dried to form a solid, and is pulverized as necessary. What was demonstrated above is the 1st form of the easily dispersible cellulose composition of this invention.

  In the production method of the present invention, an easily dispersible cellulose composition having a form in which the carboxy group of the polyolefin described above reacts with the hydroxyl group of cellulose to form an ester bond can also be obtained. Usually, such ester bonds can be formed by esterifying a polyolefin by acid halogenation or by using an esterifying agent such as dicyclohexylcarbodiimide, but the process is complicated and requires multiple steps. It is. On the other hand, in the production method of the present invention, when sufficiently dried in the above-described drying step, a product in which the ester bond is formed is obtained by sufficiently heating, dehydrating and condensing. Specifically, the water paste of the easily dispersible cellulose obtained above is obtained by dehydration condensation by heating at a temperature of 90 ° C. or higher, more preferably 120 ° C. or higher.

  In the easily dispersible cellulose composition having the ester bond formed as described above, it is not necessary that all of the carboxy groups contained in the polyolefin react with the hydroxyl groups of cellulose, and only a part of them reacts. . The easily dispersible cellulose composition of the present invention can be sufficiently used even if it does not react to form an ester bond. According to the study by the present inventors, when the polyolefin and cellulose are reacted to form an ester bond, the polyolefin is compatible with a resin which is a base material in which cellulose is dispersed. The easily dispersible cellulose composition exhibits better dispersibility of cellulose. The dehydration condensation reaction can be confirmed by confirming the ester bond with an infrared spectrophotometer (IR).

  The easily dispersible cellulose composition of the present invention in which the dispersibility of cellulose in the resin is enhanced can be easily obtained as described above. If necessary, various additives may be used in the step of depositing polyolefin. Examples of the additive include an antioxidant, a surfactant, a light stabilizer, an ultraviolet absorber, an antistatic agent, a conductive material, and the like, and these additives can be combined with an easily dispersible cellulose composition. . Further, in the step of depositing polyolefin, a granular resin such as powder or pellets, which is a base material on which cellulose is dispersed, may be added and precipitated together. Moreover, the easily dispersible cellulose composition of this invention can be made into a cellulose dispersion resin composition by drying as it is and knead | mixing to resin so that it may mention later.

(Cellulose-dispersed resin composition)
As described above, according to the production method of the present invention, a cellulose-dispersed resin composition in which cellulose is well dispersed in a resin can be obtained simply by adding to the resin and kneading and mixing. Easily dispersible cellulose composition like a masterbatch can be easily obtained. Next, the cellulose-dispersed resin composition of the present invention obtained by dispersing this easily dispersible cellulose composition in a resin will be described. The cellulose-dispersed resin composition of the present invention is a mixture of cellulose and resin obtained by melting and kneading the resin composition containing the above-described easily dispersible cellulose composition of the present invention and a resin. A cellulose-dispersed resin composition containing cellulose in a range of 0.1% to 10% on a mass basis.

  As the resin used at this time, it is preferable to use a thermoplastic resin because a cellulose-dispersed resin composition is obtained by melt kneading. Examples of the thermoplastic resin include polyamide resins such as olefin resins and nylon resins, polycarbonate resins, polysulfone resins, polyester resins, and cellulose resins such as triacetylated cellulose and diacetylated cellulose. Etc. can be used. Examples of the polyolefin resin include polyethylene, polypropylene, polycyclodecane, polycyclopentadiene, polymethyl terpene, and the like. Polyester resins include polyethylene terephthalate, polybutylene terephthalate, polylactic acid, polycaprolactone, and the like. Polyamide resins include polyamide 6 (PA6, ring-opening polymer of ε-caprolactam), polyamide 66 (PA66). Polyhexamethylene adipamide), polyamide 11 (PA11, polyamide obtained by ring-opening polycondensation of undecane lactam), polyamide 12 (PA12, polyamide obtained by ring-opening polycondensation of lauryl lactam) and the like.

  Among the resins listed above, an olefin-based resin is particularly preferred because of the advantage that a sufficient reinforcing effect can be obtained when the cellulose-dispersed resin composition is used, and the advantage that it is inexpensive. Examples of the olefin resin include polyalkene resins such as polyethylene resins and polypropylene resins, and may be used as a mixed resin of two or more. More specifically, high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyethylene-based resins (PE) such as biopolyethylene, and polypropylene-based resins (PP) are preferable. More preferably, as the polyolefin that is a resin used for forming the resin composition, it is preferable to use a polymer having the same skeleton as the polyolefin constituting the above-described easily dispersible cellulose composition. This is because the easy-dispersible cellulose composition and the resin can be completely mixed. Therefore, for example, if a resin to disperse cellulose is determined, the resin is used, and this is converted into a carboxy group to obtain an emulsion for use in the production method of the present invention. If it comprises so that a thing may be obtained, when it mixes, it can be set as the state which was completely mixed and compatible. Thus, the polyolefin emulsion used in the production method is not determined in advance, but an easily dispersible cellulose composition having a structure suitable for the resin is prepared according to the resin serving as a base material for dispersing cellulose. The ability to do this is also a major feature of the present invention.

  The cellulose content contained in the cellulose-dispersed resin composition of the present invention is 0.1% or more and less than 10% on a mass basis. If it is less than 0.1%, the performance of the cellulose is not sufficiently exhibited, and if it is more than 10%, the cellulose becomes excessive and the surface may become rough. More preferably, they are 0.5% or more and 10% or less, More preferably, they are 0.5% or more and 8% or less.

  According to the present invention, the easily dispersible cellulose composition of the present invention is added to a resin that is a dispersion medium as listed above, and is subjected to normal kneading, melt mixing, and dispersion to form an easily dispersible cellulose. The cellulose-dispersed resin composition of the present invention in which celluloses such as CNF are dispersed can be easily obtained by compatibilizing the polyolefin to be dispersed with the resin as the dispersion medium. The method for producing the cellulose-dispersed resin composition of the present invention is not particularly limited, and conventionally known methods can be used for mixing the easily dispersible cellulose composition and the resin. For example, they are mixed and dispersed by a mixing roll, a Banbury mixer, a kneader, a kneader ruder, a single-screw extruder, a multi-screw extruder, and the like. Since the temperature and mixing time for mixing and dispersing are determined depending on the resin, they cannot be generally specified, and are determined according to the resin used. Thereafter, the cellulose-dispersed resin composition is used after being cut into a sheet or pelletized with a pelletizer.

  In addition, the easily dispersible cellulose composition of the present invention used when producing the cellulose-dispersed resin composition of the present invention can be sufficiently used even after drying, but before drying when obtaining the easily dispersible cellulose composition. It is also possible to use the water paste obtained. Since cellulose may aggregate by drying, good dispersion can be achieved by using the water paste obtained in the production process as it is without drying to suppress the aggregation. The solid content of the water paste used at that time is not particularly limited. When a cellulose-dispersed resin composition is produced using an easily dispersible cellulose composition in the form of a water paste, for example, in an extruder, the volatile components are removed by sucking moisture with a vent or the like. To do.

  Moreover, when manufacturing the cellulose dispersion resin composition of this invention, you may add another additive. Specifically, compatibilizers, antioxidants, light stabilizers, surfactants, colorants such as pigments and dyes, metal powders, plasticizers, fragrances, ultraviolet absorbers, leveling agents, conductive materials, antistatic agents 1 or more can be used, and the amount to be added is arbitrary.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to these examples. Hereinafter, “parts” and “%” in the text are based on mass unless otherwise specified.

[Example 1] <Preparation of easily dispersible cellulose composition-1>
19600 parts of water was added to 600 parts of softwood bleached kraft pulp (NBKP) (refiner-treated, solid content: 25%) to prepare a water suspension (slurry) having a pulp slurry concentration of 0.75% by mass. Next, the resulting slurry was subjected to mechanical defibrating using a bead mill. Furthermore, after performing the defibrating process, it was dehydrated with a filter press to obtain 1425 parts of water-containing CNF-1 (solid content: 10%).

  1000 parts of this CNF-1 is weighed in a 60 liter bat, 19000 parts of ion-exchanged water is added, and the mixture is stirred for 30 minutes at 5000 rpm with a homomixer. The mixture was switched and stirred at 600 rpm to obtain an aqueous suspension of CNF-1. This aqueous suspension contains 0.726% cellulose.

  Next, in a separate container, 13537.5 parts of polyolefin emulsion-1 (hereinafter referred to as POE-1) is weighed, added to the aqueous suspension of CNF-1 obtained above and stirred, and the cellulose and polyolefin are mixed. A mixed aqueous solution was obtained. At this time, the pH was 8.9. To POE-1 used above, after grafting maleic anhydride onto polyethylene (hereinafter referred to as PE-1), an aqueous sodium hydroxide solution was added while melting and stirring with a powerful stirrer. Emulsified. The polyolefin emulsion used in other examples was also produced by the same method. The physical properties of POE-1 used above are as follows. PE-1 has an acid value of 30.0 mg KOH / g, a melting point of 107 ° C., POE-1 is a pale water-soluble liquid with a solid content of 20%, pH 9.2, and a slight transparency. The average particle diameter measured with a diameter measuring machine is 110.3 nm.

  1% hydrochloric acid was prepared in a separate container. While stirring the mixed aqueous solution of cellulose and polyolefin obtained above at 600 rpm, the prepared 1% hydrochloric acid was gradually added until the pH reached 3.0. At this time, thickening was observed at pH around 5-6. Next, the mixture was heated to 60 ° C. in a water bath, stirred for 1 hour, suction filtered, and thoroughly washed with ion exchange water until the pH of the filtrate became neutral. And 11585 parts of water paste of the cellulose resin processed product (CP-1) was obtained. The solid content was measured and found to be 24.6%. This solid content is a value when it reaches a constant weight at 130 ° C. with an infrared moisture measuring machine. Hereinafter, the solid content was measured by this method. This solid content is a processed resin product of cellulose containing 5% cellulose.

[Example 2] <Production of easily dispersible cellulose composition-2>
Half of the water paste of the cellulose resin treated product (CP-1) obtained in Example 1 was heated and dried at 90 ° C. for 24 hours, and then heated and dried at 120 ° C. for 24 hours. When comparing the IR of this CP-1 before heating / drying and after heating / drying, only 1694 cm ⁻¹ , which is considered to be the peak of the carboxy group, was observed before heating / drying. , those after heating and drying, in addition to 1694cm ^-1 esterification peak of 1745 cm ^-1 were observed. From this, it is considered that the ester bond was formed by the reaction between the carboxy group of the polyolefin composing CP-1 and the carboxy group of cellulose in the heating and drying treatment described above. The product after heating and drying is referred to as CP-1D. Also in the following examples, dried cellulose resin treated products were prepared by this method, and all were confirmed for the presence of ester bonds by IR.

[Examples 3 and 4] <Preparation of easily dispersible cellulose composition-3 and -4>
Cellulose resin-treated products (easily dispersible cellulose compositions) were prepared in the same manner as in Example 1 except that the amount of polyolefin used in Example 1 was changed as described in Table 1. These are designated as Examples 3 and 4, and are shown in Table 1 together with the configurations of Examples 1 and 2.

[Examples 5 to 10] <Preparation of easily dispersible cellulose composition-5 to -10>
Instead of POE-1 which is the polyolefin emulsion used in Examples 1 to 3, POE-2, POE-3, POE-4 and POE-5 which are polyolefin emulsions described later are used, respectively. Cellulose resin-treated products were produced in the same manner as in any of Example 3. This was made into Examples 5-10. These configurations are summarized in Table 2. As shown in Table 2, the cellulose resin treated product (easily dispersible cellulose composition) of Example 5 was not esterified just by drying the obtained water paste. In addition, the cellulose resin-treated product (easily dispersible cellulose composition) of Example 10 was a dry product obtained by further subjecting a water paste obtained in the same manner as in Example 9 to dehydration condensation in the same manner as in Example 2. It is.

The polyolefin emulsions used in obtaining the cellulose resin treated products (easily dispersible cellulose compositions) of Examples 5 to 10 were POE-2, POE-3, POE-4 and POE-5 having the following properties, respectively. Was used.
POE-2: Polyolefin is polyethylene (PE), its acid value is 45.3mgKOH / g, melting point is 102 ° C, solid content of emulsion is 15%, pH is 9.2, clear water-white water Liquid with an average particle diameter of 79 nm.
POE-3: Polyolefin is polyethylene (PE), its acid value is 15.9 mgKOH / g, melting point is 110 ° C., emulsion solid content is 15%, pH is 9.0, milky liquid, The average particle size is 178 nm.
POE-4: Polyolefin is polypropylene (PP), acid value is 17.0 mg KOH / g, melting point is 100 ° C., solid content of emulsion is 20%, pH is 8.9, white liquid, average The particle diameter is 212 nm.
POE-5: Polyolefin is polypropylene (PP), its acid value is 26.3 mg KOH / g, melting point is 120 ° C., emulsion solid content is 20%, pH is 9.5, white liquid, average The particle diameter is 257 nm.

[Comparative Examples 1-7] <Cellulose-containing compositions-1-7>
The cellulose-containing compositions of Comparative Examples 1 to 7 were used as compositions containing cellulose as shown below. The cellulose-containing composition of Comparative Example 1 is a water-containing CNF-1 that has been subjected to the defibrating treatment previously used in Example 1, and the cellulose-containing composition of Comparative Example 2 is a CNF-1 in this water-containing state. It is CNF-1D of the dried material obtained by drying. In the cellulose-containing composition of Comparative Example 3, when the cellulose resin treated product CP-1 of Example 1 was obtained, the cellulose content obtained by increasing the amount of cellulose used was increased to 50% ( (Comparative CP-1 with relatively small amount of polyolefin) The cellulose-containing composition of Comparative Example 4 is a comparative CP-1D of a dried product obtained by drying the comparative CP-1.

  The cellulose-containing composition of Comparative Example 5 was made of polyethylene having a high acid value and a low melting point instead of POE-1 of the polyolefin emulsion used when obtaining the cellulose resin treated product CP-1 of Example 1. Comparative CP-2 was obtained by treating CNF-1 in the same manner except that the polyolefin emulsion POE-6 having the following properties was used. The properties of POE-6, which is an emulsion of polyethylene, is a white liquid having an acid value of polyethylene of 135 mgKOH / g, a melting point of 55 ° C., a solid content of 30% and a pH of 9.5, and an average particle size of 50 nm.

  In Comparative Example 6, instead of the polyolefin emulsion POE-1 used in Example 1, a polyolefin emulsion POE-7 having the following properties made of polypropylene having a large average particle diameter and forcedly emulsified with a surfactant was used. Although it carried out similarly to Example 1, since it emulsified with surfactant, when acid was added, polyolefin did not fully precipitate, but it was not able to obtain a resin treatment thing. The property of POE-7, which is a polypropylene emulsion, is a white liquid with an acid value of 10 mgKOH / g, a melting point of 120 ° C., and forced emulsification with a surfactant, with a solid content of 20% and a pH of 8.0. The diameter is 580 nm.

  In Comparative Example 7, in place of the polyolefin emulsion POE-1 used in Example 1, a polyolefin emulsion POE-8 having the following properties made of polyethylene and having a large average particle diameter was used in the same manner. 1 was processed to obtain comparative CP-3. The properties of POE-8, which is a polyethylene emulsion, is a white liquid having an acid value of 25 mgKOH / g, a melting point of 85 ° C., a solid content of 40% and a pH of 9.5, and an average particle size of 800 nm. As a result, when acid was added, polyolefin precipitated, but the filtration was very slow. The reason for this is unknown, but slow filtration means that the hydrophilicity of cellulose acts and is difficult to filter, i.e., the emulsion particle size is larger than that of nano-sized cellulose. It is speculated that it could not be included well.

[Evaluation A]
The dispersibility of cellulose was evaluated using the cellulose resin-treated product or cellulose-containing composition obtained above.
[Evaluation-1] <Dispersibility in hot xylene>
CP-1D of Example 2 in which an ester bond is formed on the olefin, CP-4H of Example 5 obtained by simply drying the obtained water paste, CNF- of Comparative Example 2 obtained by drying water-containing CNF-1 About 1D, the dispersibility to a hot xylene was evaluated as follows. A small amount of the above was added to a 10 ml sample bottle, xylene was added, a stirrer piece was added, and the mixture was heated and stirred to near the boiling point of xylene.

  As a result, CNF-1D of Comparative Example 2 was not dispersed at all. In contrast, CP-1D of Example 2 and CP-4H of Example 5 both had CNF dispersed in xylene. The obtained results are shown in FIG. From the left of FIG. 1, the results of CNF-1D, CP-1D (cellulose is 5% in the easily dispersible cellulose composition), and CP-4H (cellulose is 10% in the easily dispersible cellulose composition) are shown.

  From the above results, in the sample of the example, CNF exists in a state of being dispersed in the polyolefin resin in the emulsion, the polyolefin constituting the sample of the example is dissolved in hot xylene, and the cellulose is dispersed in xylene. It shows that it is in the state.

[Evaluation-2] <Dispersion state of cellulose in easily dispersible cellulose resin composition>
A small amount of CP-6 obtained using the polypropylene emulsion of Example 7 was placed on a glass plate with a pattern, heated and dried using a hot plate, further covered with a glass plate, and hot-pressed. A film consisting of -6 was obtained.

  As a result, as shown in FIG. 2, it was confirmed that the formed film was a slightly translucent film in which the underlying pattern was clearly visible, and CNF-1 was well dispersed. That is, it can be seen that CP-6 of Example 7 contains 5% of CNF, but exhibits good dispersibility in the formed resin film. FIG. 3 is an electron micrograph of the film formed above. From this figure, it was confirmed that CNF was well dispersed.

  It confirmed similarly to the above also about the easily dispersible cellulose resin composition of another Example. As a result, in all cases, a transparent film was obtained, and it was found that CNF was well dispersed in the film. However, when a film was formed in the same manner using the comparative CP-3 of Comparative Example 7 obtained by using the polyolefin emulsion POE-8 having a higher acid value and a larger average particle size than specified in the present invention, it was And showed that the cellulose was not well dispersed. The reason for this is presumed that, as described above, since cellulose is not included well, the cellulose is aggregated by hydrogen bonds, and a good dispersion of CNF cannot be obtained.

[Example 11] <Production of cellulose-dispersed resin composition>
Using a cellulose resin treated product (easily dispersible cellulose composition) CP-1 which is a composition of cellulose and polyolefin of Example 1, a resin composition is prepared by mixing with resin and dispersing cellulose. The obtained resin composition was evaluated. The resin used for preparing the resin composition is the same polyethylene PE-1 as used for POE-1, which is a polyolefin emulsion used when preparing CP-1. The amount of polyethylene used for mixing with CP-1 was such that 2.5% of cellulose was contained in the resulting resin composition.

  Preparation of the resin composition formed by dispersing cellulose was performed by biaxial extrusion kneading CP-1 and PE-1 and pelletized by the following method. And the film was created like the method performed by above-mentioned evaluation-2 using the obtained pellet, and the dispersion degree of the cellulose was confirmed. More specifically, biaxial extrusion kneading of CP-1 and PE-1 was performed at a kneading temperature of 140 ° C., and moisture was sucked into the vent. Subsequently, it was discharged in a strand shape, cooled, and cut with a pelletizer to prepare PE resin pellets in which cellulose was dispersed. The number of passes in the above twin screw extrusion kneader is only one.

  The obtained PE resin pellets in which cellulose was dispersed were finely cut, and a film was prepared in the same manner as described in Evaluation-2. As a result, the formed film was almost transparent, and it was confirmed that cellulose was well dispersed in the polyethylene resin. This indicates that sufficient dispersibility of cellulose in the resin can be obtained even when the number of passes in the twin-screw extrusion kneader is only one. CP-1 of Example 1 is a polyethylene resin. On the other hand, it can be judged that it is easily dispersible.

[Example 12] <Cellulose-dispersed resin composition and comparative example>
In the same manner as in Example 11, using the cellulose resin-treated product (easily dispersible cellulose composition) that is a composition of cellulose and polyolefin (PE or PP) of Examples 2 to 8 prepared above, respectively. Thus, resin pellets which are resin compositions obtained by dispersing cellulose were obtained. Moreover, about the cellulose resin processed material (easily dispersible cellulose composition) of Example 9, 10, the polypropylene resin was used for resin and the PP resin pellet formed by disperse | distributing a cellulose was obtained. Then, using the obtained PE resin pellets or PP resin pellets, films were formed in the same manner as in Example 11 to evaluate the dispersibility of cellulose in the resin. As a result, in all Examples, a transparent film could be obtained and good dispersibility was exhibited. Moreover, it is shown that sufficient dispersibility of cellulose in the resin can be obtained even if the number of passes in the twin-screw extrusion kneader is only one, and the cellulose resin treated products of Examples 2 to 10 (easy dispersibility) It can be judged that any of the cellulose compositions is easily dispersible with respect to the polyolefin resin.

[Comparative Example 8] <Cellulose-dispersed resin composition and comparative example>
Each of the cellulose-containing compositions of Comparative Examples 1 to 5 and 7 prepared above was used, and the above-described polyethylene (PE-1) resin was used so that the cellulose content was 2.5%. In the same manner as in Example 11, PE resin pellets, which is a resin composition containing cellulose of a comparative example, were obtained. Then, using the obtained PE resin pellets, a film was formed in the same manner as in Example 11, and the dispersibility of cellulose in the resin was evaluated.

  As a result, when the cellulose-containing compositions of Comparative Examples 1, 2, 3, and 4 were used, when they were biaxially extruded and kneaded with PE resin, there were fibrous ones that were loose and pulled, and the strands were also drawn. It was found that the cellulose was not dispersed at all. The reason for this is the same as in the case of the dispersion in xylene tested above, in the case of the cellulose-containing composition of Comparative Examples 1 and 2, which was not treated with resin, a non-polar highly hydrophobic PE resin Then, it is considered that the hydrogen bond of cellulose is strong, and the cellulose was not dispersed even when biaxial extrusion kneading.

  In addition, the cellulose-containing compositions of Comparative Examples 3 and 4 obtained by increasing the amount of cellulose treated with the resin have a relatively small amount of resin even when treated with a polyolefin emulsion as in the Examples. It is considered that sufficient cellulose cannot be included, and the cellulose is in an aggregated state by the treatment, and even if biaxial extrusion kneading is performed, sufficient cellulose cannot be dispersed. Moreover, since the melting point of the polyethylene which comprises the emulsion used for the process of the cellulose of the comparative example 5 was as low as 55 degreeC, the obtained strand was soft. The degree is such that it can be cut even if pulled by hand, and it is considered that the resin composition is not resistant. Moreover, when the cellulose containing composition of the comparative example 7 was used, although it was pelletized, the formed film | membrane is whitish and it is thought that the cellulose is not fully disperse | distributing.

[Evaluation B] <Biaxial extrusion kneading, injection molding and tensile test>
The PE resin pellets obtained using the PE resin pellets of Examples 11 and 12 obtained above and the cellulose-containing composition of Comparative Example 7 were each subjected to injection molding, and dumbbell pieces (dumbbell thickness: 2 mm) ) Was prepared as an evaluation sample. Each of the dumbbell pieces of the obtained sample for evaluation was subjected to a tensile test at a tensile speed of 10 mm / min using a tensile tester (manufactured by Instron Co., Ltd .: universal tester 5900 series used), and tensile modulus and tensile strength Were measured and evaluated. The results obtained are summarized in Table 3. For comparison, the same test was performed for polyethylene (PE-1) resin to which cellulose was not added, and the results are shown in Table 3.

  As shown in Table 3, the cellulose resin composition obtained by using the easily dispersible cellulose composition of the example of the present invention has improved mechanical properties due to good dispersion of nano-sized cellulose. The tensile modulus and tensile strength were both high. Further, even when biaxial extrusion kneading as a water paste containing a liquid component, a sufficient further improvement in mechanical strength was confirmed as compared with the case of using only polyethylene (PE-1) resin. In the embodiment using the water paste, it is considered that the cost is reduced by omitting the drying step. On the other hand, in the case of using the cellulose-containing composition of Comparative Example 7, since the cellulose does not disperse well in the olefin, the elastic modulus is the effect of adding cellulose compared to the case of the polyethylene (PE-1) resin alone. A slight improvement was observed, but the strength decreased.

  As explained above, the cellulose-dispersed resin composition obtained by carrying out the easily dispersible cellulose composition of the present invention and the method for producing the same as, for example, a pretreatment step in producing a cellulose-dispersed PE resin. The cellulose is well dispersed, and in addition, the cellulose can be easily dispersed, and the resin containing the cellulose and the molded product have characteristics of excellent tensile modulus and tensile strength. Moreover, since the technology provided by the present invention contributes to effective utilization of natural resources such as cellulose, it is environmentally friendly and can reduce fossil materials. Moreover, it is thought that the low specific gravity of a cellulose demonstrates an effect with the technique provided by this invention also at the point of weight reduction of a resin product. The cellulose-dispersed resin composition provided in the present invention is a housing for electrical components such as automobile members, televisions, telephones, watches, etc., a housing such as a mobile communication device such as a mobile phone, a printing device, a copying machine, a sports equipment, etc. It is useful for structural material applications such as, and is expected to be widely used.

Claims (11)

  An easily dispersible cellulose composition having improved dispersibility of cellulose in a resin, comprising cellulose and polyolefin, wherein the cellulose is selected from the group consisting of cellulose nanofibers and cellulose nanocrystals. A fiber, the polyolefin is a polyalkene, has a carboxy group, an acid value of 50 mgKOH / g or less, a melting point of 80 ° C. or more, and the cellulose in an amount of 5% to 30% by mass. % Easily dispersible cellulose composition characterized by containing.   The easily dispersible cellulose composition according to claim 1, wherein the cellulose further contains at least one cellulose fiber selected from the group consisting of pulp, lignocellulose, and wood flour.   The easily dispersible cellulose composition according to claim 1 or 2, wherein a carboxyl group of the polyolefin reacts with a hydroxyl group of the cellulose to form an ester bond. In the method for producing an easily dispersible cellulose composition having improved dispersibility of cellulose in a resin,
A polyolefin emulsion of a polyolefin, which is a polyalkene having a carboxy group, is mixed with water-containing or dried cellulose to obtain a mixed aqueous solution of cellulose and a polyolefin emulsion, and then an acid is added to precipitate the polyolefin. The polyolefin emulsion used in this step is formed by neutralizing a polyolefin having an acid value of 50 mg KOH / g or less and a melting point of 80 ° C. or more with an alkali and emulsifying the particles in water, and resulting particles by light scattering. A polyolefin emulsion having an average particle diameter of 300 nm or less measured by a diameter measuring machine,
The cellulose is at least one cellulose fiber selected from the group consisting of cellulose nanofibers and cellulose nanocrystals;
The method for producing an easily dispersible cellulose composition, wherein the mixed aqueous solution contains the polyolefin in a range of 233.3 parts to 1900 parts on a mass basis with respect to 100 parts of the cellulose.   The method for producing an easily dispersible cellulose composition according to claim 4, wherein the cellulose further contains at least one cellulose fiber selected from the group consisting of pulp, lignocellulose, and wood flour.   The method for producing an easily dispersible cellulose composition according to claim 4 or 5, wherein a content of cellulose in the mixed aqueous solution is 3% or less on a mass basis. After the step of precipitating the polyolefin, the method further comprises a step of heating at a temperature of 90 ° C. or higher, and in this heating step, the carboxy group of the polyolefin is reacted with the hydroxyl group of the cellulose to dehydrate and condense, The manufacturing method of the easily dispersible cellulose composition of any one of Claims 4-6 which forms a coupling | bonding.   A cellulose-dispersed resin composition, which is a mixture of cellulose and a resin, wherein the cellulose has a highly dispersible cellulose composition in which the dispersibility of the cellulose according to any one of claims 1 to 3 is enhanced. A cellulose-dispersed resin composition comprising 0.1% or more and 10% or less of cellulose on a mass basis in the composition.   The cellulose-dispersed resin composition according to claim 8, wherein the resin is a polyolefin that is a polyalkene and a polymer having the same skeleton as the polyolefin constituting the easily dispersible cellulose composition. A production method for obtaining a cellulose-dispersed resin composition, which is a mixture of cellulose and resin,
Polyolefin emulsion having a carboxy group, which is a polyolefin emulsion obtained by neutralizing a polyolefin having an acid value of 50 mgKOH / g or less with an alkali, is mixed with cellulose in a water-containing state or in a dry state, and a mixed aqueous solution of cellulose and polyolefin emulsion is prepared. In obtaining the cellulose, at least one cellulose fiber selected from the group consisting of cellulose nanofibers and cellulose nanocrystals is used as the cellulose, and the mixed aqueous solution is based on mass, and the polyolefin is added to 100 parts of the cellulose. An easily dispersible cellulose composition having an increased dispersibility in a resin of cellulose obtained by adding an acid to the mixed aqueous solution and precipitating polyolefin by adding an acid to the mixed aqueous solution in the range of 233.3 parts to 1900 parts. Use
A method for producing a cellulose-dispersed resin composition, comprising mixing with a resin while containing a liquid component resulting from the production of the easily dispersible cellulose composition to obtain a cellulose-dispersed resin composition.   The polyolefin emulsion is a polyolefin emulsion in which a polyolefin having a melting point of 80 ° C. or more is neutralized with an alkali and emulsified in water, and an average particle size measured by a particle size measuring device by light scattering is 300 nm or less. Item 11. A method for producing a cellulose-dispersed resin composition according to Item 10.