JP7031144B2 - Resin molded body, manufacturing method of resin molded body, and resin composition - Google Patents

Description

The present invention relates to a resin molded product containing a composite containing flat metal fine particles and finely divided cellulose, a method for producing the resin molded product, and a resin composition used for producing the resin molded product.

Packaging materials such as foods, pharmaceuticals, and electronic members are required to have a barrier property of oxygen and water vapor, and to have high water resistance and strength in order to protect the contents. Although the aluminum foil laminated film has a high gas barrier property, it is said that the contents cannot be confirmed from the outside and it affects the sales at the time of purchase. As described above, in recent years, a transparent gas barrier packaging material capable of confirming the state of the contents has been used.

Conventionally, polyvinylidene chloride or the like, which is less affected by temperature and humidity, has been used as a transparent gas barrier material. Due to the recent increase in awareness of environmental problems, a copolymer of polyvinyl alcohol (PVA) and ethylene vinyl alcohol or a film coated with these resins is used as a non-chlorine gas barrier material.

As the film obtained by using the PVA-based polymer, the melt is used, for example, a melt extrusion film forming method, a wet film forming method (discharge into a poor solvent), and a gel film forming method (PVA-based polymer). A method of obtaining a film by extracting and removing the solvent after temporarily cooling and gelling the aqueous solution), a cast film forming method (a method of casting a PVA-based polymer solution on a substrate and drying it to obtain a film), and these. A method based on the combination of the above can be mentioned. The obtained film has excellent transparency and mechanical properties, and has high adhesiveness regardless of the type of adherend, and is therefore widely used as a film material.
Furthermore, since the amount of organic solvent discharged in the film manufacturing process is extremely small, it is expected that its use as a VOC-friendly material will be further expanded in the future as environmental regulations are becoming stricter in recent years.

On the other hand, since PVA-based polymers have a hydroxyl group in the molecular skeleton, they have high responsiveness to water, and moisture absorption causes changes in characteristics such as mechanical properties and gas barrier properties, so their applications are limited. Met. Further, there is a problem that the thermal deformation is remarkably increased by activating the molecular motion due to the loosening of hydrogen bonds between and within the molecule at high temperature, and the temperature range used is limited. Therefore, various techniques for hydrophobization and crosslinking of PVA-based polymers have been developed and widely proposed as measures against water resistance and thermal deformation (see Patent Document 1). However, these have little effect on improving the characteristics at high temperatures and are not suitable for suppressing the motility of PVA-based polymers.

In recent years, functional materials using natural polymers, which are sustainable environmentally friendly materials, have been actively developed, and it is expected that petroleum-derived materials will be replaced with biomass materials. For example, as an environment-friendly natural polymer material having biodegradability, a plant material such as cellulose is known. Cellulose, which is the main component of plants and wood, is the most abundant natural polymer material accumulated on the earth. In wood, several tens or more of cellulose molecules are bundled to form fine fibers (microfibrils) having high crystallinity and a fiber diameter on the order of nanometers. Furthermore, a large number of fine fibers are hydrogen-bonded to each other to form cellulose fibers, which serve as plant supports.

A method of using this cellulose fiber by making it finer (nanofiber) until the fiber diameter reaches the nanometer order is known. For example, a method is known in which an N-oxyl compound is used as an oxidation catalyst and a part of the hydroxyl group of cellulose is oxidized to form at least one functional group selected from the group consisting of a carboxy group and an aldehyde group. According to this method, finely divided cellulose having a cellulose I-type crystal structure (hereinafter, also referred to as “CSNF”) having a maximum fiber diameter of 1000 nm or less and a number average fiber diameter of 2 nm to 150 nm can be obtained. (See, for example, Patent Document 2).
The use of the finely divided cellulose for gas barrier packaging materials (see Patent Document 3) and for improving the strength of the resin by compounding with the resin (see Patent Document 4) are being studied.

Japanese Patent No. 3992827 Japanese Unexamined Patent Publication No. 2008-1728 Japanese Unexamined Patent Publication No. 2012-149114 Japanese Patent No. 6020334

However, in a transparent gas-barrier packaging material using a PVA-based polymer or finely divided cellulose, some molecular bonds are broken by light such as ultraviolet rays or visible light, resulting in discoloration of the dye in the contents and oxidation of lipids. Hydrolysis and the generation of deteriorated odor may be a problem.

In view of the above circumstances, the present invention provides a resin molded product suitable for a transparent gas barrier packaging material, a method for producing a resin molded product, and a resin composition used for producing the resin molded product. With the goal.

One aspect of the present invention comprises a resin , a composite containing flat metal fine particles and finely divided cellulose, the resin being a polyvinyl alcohol-based polymer, and the composite having the flat plate shape. The metal fine particles and at least one or more of the finely divided celluloses are composited, and at least a part or all of each of the finely divided celluloses is incorporated into the flat metal fine particles, and at least a part of the finely divided celluloses is incorporated. A part thereof is composited so as to be exposed on the surface of the flat metal fine particles, and at least a part of the hydroxy groups of the finely divided cellulose and the hydroxy groups of the resin are the methyl vinyl ether anhydride maleic acid copolymer. It is a resin molded product cross-linked by a cross-linking agent selected from the group consisting of isobutylene anhydride maleic acid copolymer and maleic acid .

Two aspects of the present invention include a process for producing finely divided cellulose, a process for producing a complex, and a process for producing a complex.
It is a method of manufacturing a resin molded product which comprises a resin composition preparation step and a resin molded product manufacturing step, and forms the above-mentioned resin molded product on a support by wet coating.

The three aspects of the present invention include a resin, a composite containing flat metal fine particles and finely divided cellulose, and a cross-linking agent, wherein the resin is a polyvinyl alcohol-based polymer and the cross-linking agent is a cross-linking agent.
It is a cross-linking agent selected from the group consisting of methyl vinyl ether maleic anhydride copolymer, isobutylene maleic anhydride copolymer, and maleic acid, and the complex is the flat metal fine particles and at least one micronized. At least a part or all of each of the finely divided celluloses is incorporated into the flat metal fine particles, and at least a part of the finely divided cellulose is incorporated into the flat metal fine particles. It is a resin composition composited so as to be exposed on the surface.

According to the present invention, it is possible to provide a resin molded product suitable for a transparent gas barrier packaging material, a method for producing the resin molded product, and a resin composition used for producing the resin molded product.

It is a figure which shows typically the resin molded body which concerns on one Embodiment of this invention. It is a figure which shows typically the complex which concerns on one Embodiment of this invention. It is a figure (transmission electron microscope image) which shows the result of uranyl staining and magnifying and observing the complex which concerns on one Embodiment of this invention with a transmission electron microscope (TEM). It is a figure which shows the result of having observed the complex which concerns on one Embodiment of this invention with a scanning electron microscope (SEM). It is a figure which shows the result of magnifying and observing the complex which concerns on one Embodiment of this invention with a scanning transmission electron microscope (STEM). It is a figure which shows the result of magnifying and observing the complex which concerns on one Embodiment of this invention with a scanning electron microscope (SEM). It is a figure which shows the result of having observed the complex which concerns on one Embodiment of this invention from the cross-sectional direction by the transmission electron microscope (TEM). It is a figure which shows the result of having measured the transmittance of the micronized cellulose aqueous dispersion liquid of Example 1. FIG. It is a figure which shows the evaluation result of the viscosity characteristic of the micronized cellulose aqueous dispersion liquid of Example 1. FIG. 9 is a scanning transmission electron microscope (STEM) image of the complex of Example 1. 9 is a scanning transmission electron microscope (STEM) image of the complex of Example 5. 9 is a scanning transmission electron microscope (STEM) image of the complex of Example 6.

Hereinafter, the resin molded product according to the embodiment of the present invention, the method for producing the resin molded product, and the resin composition used for producing the resin molded product will be described in detail with reference to the drawings. The drawings used in the following description are for explaining the configuration of the embodiment of the present invention, and the sizes, thicknesses, dimensions, etc. of the illustrated parts may differ from the actual dimensional relations.

FIG. 1 is a diagram schematically showing a resin molded body 1 according to the present embodiment. FIG. 1 is a diagram schematically showing a complex 2 contained in a resin molded body 1.
As shown in FIGS. 1 and 2, the resin molded body 1 includes at least a resin 11 having a crosslinked structure, and a composite 2 containing flat metal fine particles 21 and finely divided cellulose 22.

Nano-sized particles (hereinafter referred to as "fine particles") have properties not found in bulk. For example, as the particles become smaller, the total surface area of the particles increases, so that the catalytic performance of the particles increases. When the particles become nano-sized, the melting point decreases, so that the particles can be fired at a low temperature. Furthermore, depending on the size of the particles, the optical properties of the particles also change significantly. Oxides and the like having a small refractive index become transparent when they are uniformly dispersed in a liquid or the like because light scattering becomes very small when the size is 1/10 or less of the wavelength region of visible light. In the case of metal fine particles, the collective vibration of free electrons in the particles resonates with a specific wavelength, and by absorbing the light of that wavelength, various color tones appear.

By controlling the shape and particle size of the metal fine particles, it is possible to control their catalytic activity and optical characteristics. In metal fine particles, a phenomenon occurs in which an electric field generated by causing vibration of free electrons and an external electric field (light, etc.) resonate (localized surface plasmon resonance (LSPR)). This surface plasmon resonance causes absorption of light in a specific wavelength range. If the resonance wavelength range is a rod shape or a flat plate shape, the resonance wavelength greatly changes depending on the aspect ratio of the long axis / the short axis.
Therefore, the flat metal fine particles 21 can absorb or reflect light in a specific wavelength region such as a visible light region to a near infrared region and shield it by controlling its aspect ratio.

While studying the functionalization of the finely divided cellulose 22, a composite of the flat metal fine particles 21 and the finely divided cellulose 22, which is a new material in which the finely divided cellulose 22 and the flat metal fine particles 21 are combined (flat metal / fine). Cellulose-forming complex) 2 was developed. The complex 2 can shield light rays in a specific wavelength region from the visible light region to the infrared region by LSPR, which is a feature of the flat metal fine particles 21.

As a result of studies by the present inventors, the resin molded body 1 containing at least the resin 11 having a crosslinked structure and the composite 2 has stable light ray-cutting performance and gas barrier property in a specific wavelength region for a long period of time, and therefore oxygen. It is possible to prevent oxidation of the contents by gas, fading and deterioration of the contents by light, and generation of odor, and it has high water resistance, high strength, good dimensional stability, and antibacterial. It has been found that a resin molded product 1 exhibiting properties can be obtained.
By containing the composite 2 in the resin 11, it is possible to stably shield light in a specific wavelength region for a long period of time, and the effect of the finely divided cellulose 22 bonded to the composite 2 makes it a good machine. Dimensional stability can be imparted by preventing the resin molded body 1 from expanding and contracting due to its characteristics and high temperature.
Further, since the composite 2 contained in the resin molded product 1 of the present embodiment is easier to concentrate as compared with the finely divided cellulose alone, it is possible to reduce the energy required for removing the solvent when producing the molded product. Therefore, it is possible to obtain a resin molded product 1 having high productivity, high strength, and high dimensional stability.

The resin molded body 1 refers to various forms such as a film shape, a sheet shape, and a structure. The resin molded body 1 can be produced by using, for example, a resin composition containing a complex 2, a resin 11, and a cross-linking agent. The resin composition is a composition containing the complex 2, the resin 11, and a cross-linking agent, and refers to a state before structural formation or reaction by heating or light.

Hereinafter, the details of the complex 2, the method for producing the complex 2, the resin 11, and the cross-linking agent will be described, and then the method for producing the resin molded body 1 will be described in detail.

[Complex 2]
The complex 2 is a complex (flat metal / finely divided cellulose complex) having the flat metal fine particles 21 and the finely divided cellulose 22.
As shown in FIG. 2, the composite 2 is made into a flat metal fine particle 21 in which a flat metal fine particle (flat metal fine particle) 21 and at least one or more finely divided cellulose 22 are composited. It is a composite with cellulose 22, and at least a part (part) or all of each of the finely divided cellulose 22 is incorporated into the flat metal fine particles 21, and the rest is exposed on the surface of the flat metal fine particles 21. It is a composite.
Since the resin molded body 1 contains the composite body 2, the resin molded body 1 capable of selectively shielding light in a specific wavelength region can be obtained, and the strength of the resin molded body 1 is improved, resulting in dimensional stability. It is possible to impart and improve gas barrier properties.

FIG. 3 is an observation image obtained by staining the complex 2 with uranyl and magnifying it with a transmission electron microscope (TEM).
4 (a) is an observation image of the complex 2 observed with a scanning electron microscope (SEM), and FIG. 4 (b) is a schematic diagram of FIG. 4 (a).
5 (a) is an observation image of the complex 2 magnified and observed by a scanning transmission electron microscope (STEM), and FIG. 5 (b) is a schematic diagram of FIG. 5 (a).
FIG. 6A is an observation image obtained by magnifying and observing the complex 2 with a scanning electron microscope (SEM), and FIG. 6B is a schematic diagram of FIG. 6A.

As shown in FIGS. 3 to 6, each of the micronized cellulose 22 has a portion (one end) 22a incorporated in the flat metal fine particles 21 and a portion exposed on the surface of the flat metal fine particles 21 (one end). The other end) is composed of 22b. Due to the presence of one end 22a incorporated in the flat metal fine particles 21, the flat metal fine particles 21 and the respective finely divided cellulose 22 are inseparable. That is, the flat metal fine particles 21 and the finely divided cellulose 22 are physically separated from each other by incorporating at least a part (that is, one end portion 22a) of the finely divided cellulose 22 into the flat metal fine particles 21. Combined and inseparable.

Here, in the composite 2, at least a part (that is, one end 22a) of the finely divided cellulose 22 is incorporated into the flat metal fine particles 21, that is, the grain boundaries of the metal fine particles unit at the growth stage of the flat metal fine particles 21. It is synonymous with a state in which one end portion 22a of the finely divided cellulose 22 is sandwiched along the above.

Further, in the complex 2, the "indivisible" state means that it is impossible to separate the flat metal fine particles 21 and the finely divided cellulose 22 by, for example, a physical method such as a centrifuge. ..

The complex 2 also includes a configuration in which all parts (whole) of all the finely divided cellulose 22 are incorporated into the flat metal fine particles 21, and there is no exposed part on the surface of the flat metal fine particles 21. Is done. Even in the complex 2 having such a configuration, as shown in FIG. 5, the presence of the portion (one end portion) 22a incorporated in the flat metal fine particles 21 in the finely divided cellulose 22 can be confirmed.

The micronized cellulose 22 is cellulose having at least one side of the structure on the order of nanometers, and the preparation method thereof is not particularly limited. Usually, the micronized cellulose has a fibrous shape derived from a microfibril structure. Therefore, the finely divided cellulose 22 in the complex 2 is preferably fibrous as described above. By using the fibrous finely divided cellulose, the complex 2 has a more controlled shape and size. The details of the refined cellulose 22 will be described later.

(Observation of complex 2)
The observation of the complex 2 can be performed, for example, by the following method.
The composite 2 is purified by high-speed cooling centrifugation or the like, cast on a grid for a transmission electron microscope, stained with uranyl, and observed with a transmission electron microscope to obtain a transmission electron microscope image as shown in FIG. can get. According to this transmission electron microscope image, the flat metal fine particles 21 and the other end portion 22b of the finely divided cellulose 22 exposed on the surface thereof can be observed.

The composite 2 is purified by high-speed cooling centrifugation or the like, the obtained composite is cast on a silicon wafer plate, subjected to platinum vapor deposition treatment, and then a scanning electron microscope (trade name: S-4800, Hitachi High Technologies). By observing with (manufactured by the same company), scanning electron microscope images as shown in FIGS. 4 and 6 can be obtained. According to this scanning electron microscope image, the flat metal fine particles 21 and the other end portion 22b of the finely divided cellulose 22 exposed on the surface thereof can be observed.

Further, the complex produced by the method for producing the complex 2 described later is purified by high-speed cooling centrifugation or the like, and the obtained complex 2 is cast on a grid and observed with the above scanning transmission electron microscope. , A scanning transmission electron microscope image as shown in FIG. 5 can be obtained. According to this scanning transmission electron microscope image, the flat metal fine particles 21 and one end portion 22a of the finely divided cellulose 22 incorporated in the flat metal fine particles 21 can be observed.

Further, the complex 2 is purified by high-speed cooling centrifugation or the like, and the obtained complex 2 is cast on a grid and observed by the above scanning electron microscope observation without vapor deposition, and then energy dispersive X-ray analysis is performed. By performing element mapping with the above and detecting carbon by the flat metal fine particles 21 and the finely divided cellulose 22, the composite of the flat metal fine particles 21 and the finely divided cellulose 22 can be confirmed.

Generally, the metal surface and the solvent do not have a strong affinity, and the particles coagulate and precipitate as they are. However, the complex 2 is reduced in the presence of metal ions and the finely divided cellulose 22 to generate metal atoms, and through nucleation and growth, flat metal fine particles 21 are generated. In this process, it is considered that the flat metal fine particles 21 and the finely divided cellulose fibers interact with each other to affect the morphology and aggregation of the flat metal fine particles 21, and the composite 2 having a controlled shape and size can be obtained.
In the complex 2 thus obtained, at least a part or all of each of the micronized cellulose 22 is incorporated into the flat metal fine particles 21, and the rest is exposed on the surface of the flat metal fine particles 21. In the complex 2, it is preferable that the flat metal fine particles 21 and the finely divided cellulose 22 are inseparable from the viewpoint of dispersion stability.

Hereinafter, the details of the flat metal fine particles 21 and the finely divided cellulose 22 will be described.

(Plate metal fine particles 21)
By controlling the particle size and shape of the metal fine particles, it is possible to control the wavelength region to be shielded. Free electrons on the surface of metal fine particles may collectively vibrate due to an external electric field such as light. Since electrons are charged particles, an electric field is generated around them when they vibrate. The phenomenon in which the electric field and the external electric field (light, etc.) resonate due to the vibration of free electrons is called localized surface plasmon resonance (LSPR). This LSPR causes absorption and reflection of light in a specific wavelength range, and can be shielded. The metal fine particles have higher stability than organic pigments generally used as a coloring material, and can stably shield a specific wavelength region for a long period of time.

Among the metal nanoparticles having such an anisotropic shape, silver nanoparticles are particularly expected to be applied. For example, spherical silver nanoparticles having a particle size of several nm to several tens of nm are known to exhibit a yellowish tinge because they have absorption near a wavelength of 400 nm due to the LSPR. However, the anisotropically grown silver nanoparticles are not limited to this, and for example, it is known that the absorption peak of the flat plate-shaped silver nanoparticles is red-shifted. At this time, it has been confirmed that the absorption / reflection peak shifts to the longer wave side as the aspect ratio (that is, particle diameter / particle thickness) of the flat plate silver nanoparticles increases. That is, the flat silver nanoparticles can be used as an optical material that absorbs / reflects arbitrary wavelengths. Further, if the absorption / reflection wavelength is controlled in the visible light region, it is possible to obtain flat silver nanoparticles having vivid colors such as red and blue in addition to yellow, and it can be expected to be used as a functional coloring material. Furthermore, depending on the aspect ratio of the flat silver nanoparticles, it is possible to shift the absorption peak to the near-infrared region outside the visible light region.

In the present embodiment, the visible light refers to an electromagnetic wave having a wavelength region of about 400 nm to 700 nm, and the near infrared ray refers to an electromagnetic wave having a wavelength region close to visible light (about 700 nm to 2500 nm) among infrared rays. ..
In particular, some molecular bonds may be broken by light in the visible light region, which may cause problems such as discoloration of the pigment of the contents in the packaging material, oxidation and hydrolysis of lipids, and generation of deteriorated odor. By using the contained resin molded body as a packaging material, deterioration of the contents can be suppressed.
Therefore, although not particularly limited, it is preferable to have a minimum wavelength in which the transmittance is extremely minimum in the wavelength region of 400 nm or more and 700 nm or less in the transmittance spectrum of the complex dispersion liquid. The complex dispersion liquid is a dispersion liquid containing at least the complex 2 and a solvent. The complex dispersion liquid may be a dispersion liquid in which the complex is dispersed in a solvent, and refers to, for example, a dispersion liquid after a complex preparation reaction. Further, if necessary, it may be diluted with a solvent such as pure water, or the solvent may be replaced as long as at least a part of the complex is dispersed.

The flat metal fine particles 21 are flat metal fine particles, and in the present embodiment, the “fine particles” are particles having a volume particle diameter of 10 μm or less.

Here, as shown in FIG. 2, the shape of the front surface 23 or the back surface 24 of the flat metal fine particles 21 of the complex 2 is a circle having a diameter d (diameter equivalent to a circle). The diameter d is the particle diameter of the complex 2. The diameter d with respect to the thickness h of the flat metal fine particles 21 of the complex 2 is defined as the aspect ratio (d / h) of the complex 2. The "flat plate" of the flat metal fine particles 21 of the complex 2 means that the particles are plate-shaped, and the plate-like means, for example, that the average value of the aspect ratio (d / h) is 1.1 or more. It shows that there is.
The shapes of the front surface 23 and the back surface 24 of the complex 2 are not particularly limited, but are usually polygons such as hexagons and triangles. When the front surface 23 and the back surface 24 are polygonal, elliptical, or the like, the diameter d (circle equivalent diameter) is calculated on the assumption that the area of the front surface 23 or the back surface 24 is the same circle diameter.
Further, the front surface 23 and the back surface 24 of the complex 2 may have a large area, and both sides may not be parallel.

From the viewpoint of controlling the optical characteristics, it is preferable that the flat metal fine particles 21 have a flat plate shape, and the particle diameter d, the thickness h, and the aspect ratio are within the following ranges. The particle diameter d, thickness h, and aspect ratio of the flat metal fine particles 21 are equal to the particle diameter d, thickness h, and aspect ratio of the composite 2.
The average value of the particle diameter d of the flat metal fine particles 21 is preferably 2 nm or more and 1000 nm or less, more preferably 20 nm or more and 500 nm or less, and further preferably 20 nm or more and 400 nm or less.
The average value of the thickness h of the flat metal fine particles 21, that is, the average value of the distance h between the front surface 23 and the back surface 24 is preferably 1 nm or more and 100 nm or less, and more preferably 5 nm or more and 50 nm or less.
The above average value is obtained by measuring, for example, 100 particles.

The aspect ratio (average value of d / average value of h) of the flat metal fine particles 21 is 1.1 or more, preferably 2.0 or more, and more preferably 2.0 or more and 100 or less. , 2.0 or more and 50 or less is more preferable.
In particular, when the aspect ratio is 1.1 or more and 6 or less, λmax described later becomes 400 nm or more and 600 nm or less, and the transmittance at a wavelength of 660 nm becomes high. Therefore, when used as a packaging material, the contents can be visually recognized. The properties are very good, and the effect of suppressing fading / deterioration of the contents and the generation of odor is also high.

The complex 2 can change the color tone by arbitrarily changing the average value of the particle diameter d and controlling the aspect ratio thereof. Further, the complex 2 may contain the flat metal fine particles 21 and the finely divided cellulose 22, and may contain other components.

The shape and size of the flat metal fine particles 21 can be evaluated using a scanning electron microscope, a transmission electron microscope, and a scanning transmission electron microscope.
Examples of the method for measuring the particle diameter d and the thickness h of the flat metal fine particles 21 and the method for calculating the aspect ratio include the following methods.

(1) Measurement method of particle size A dispersion containing the complex 2 is cast on a copper grid with a support film for observation with a transmission electron microscope, air-dried, and then observed with a scanning transmission electron microscope. A scanning transmission electron microscope image as shown can be obtained. The diameter of the flat metal fine particles 21 in the scanning transmission electron microscope image when approximated by a circle is calculated as the particle diameter in the plane direction. The above average value is obtained by measuring 100 particles.

(2) Thickness measurement method As shown in FIG. 7, a dispersion containing the composite 2 was cast on a polyethylene terephthalate (PET) film 26, air-dried, and fixed with an embedding resin 27, and cross-sectionald with a microtome. By cutting in the direction and observing with a transmission electron microscope, a transmission electron microscope image as shown in FIG. 7 can be obtained. FIG. 7 is a diagram (transmission electron microscope image) showing the results of observing the flat metal fine particles 21 from the cross-sectional direction with a transmission electron microscope. The thickness of the flat metal fine particles 21 in the transmission electron microscope is calculated as the thickness perpendicular to the plane direction. The above average value is obtained by measuring 100 particles.

(3) Aspect ratio calculation method The average value of the diameter d (particle diameter equivalent to a circle) with respect to the average value of the thickness h of the flat metal fine particles 21 obtained as described above, and the aspect ratio (d) of the flat metal fine particles 21. (Mean value of / h).

The method for measuring the particle size and thickness of the flat metal fine particles 21 and the method for calculating the aspect ratio are examples, and the method for measuring the particle size and thickness of the flat metal fine particles 21 and the method for calculating the aspect ratio are particularly high. Not limited to these.

The method for measuring the transmittance spectrum of the complex dispersion is not particularly limited, but the complex dispersion after the complex preparation reaction is used as it is, or if necessary, diluted with a solvent such as pure water and placed in a quartz cell, and the spectral luminosity is measured. It can be measured using a meter.

The metal or metal compound constituting the flat metal fine particles 21 is not particularly limited, and any metal or metal compound can be used according to the intended use. Examples of the metal or metal compound constituting the flat metal fine particles 21 include gold, silver, copper, aluminum, iron, platinum, zinc, palladium, ruthenium, iridium, rhodium, osmium, chromium, cobalt, nickel, manganese, and vanadium. , Molybdenum, gallium, metals such as aluminum, metal salts, metal complexes and alloys thereof, oxides, double oxides and the like. Above all, it is preferable to contain at least one of gold, silver and copper, and in particular, when at least silver is contained, the complex 2 can block light having a wavelength in the visible light region to the near infrared region, and has antibacterial properties. Can also be given.
The proportion of the metal contained in the complex 2 is not particularly limited.

(Miniaturized Cellulose 22)
The finely divided cellulose 22 may have at least one side of the structure on the order of nanometers, and the preparation method thereof is not particularly limited. Since the finely divided cellulose usually has a fibrous shape derived from a microfibril structure, the finely divided cellulose 22 used in the method for producing the composite 2 of the present embodiment is preferably fibrous in the range shown below. .. By using the fibrous finely divided cellulose 22, a complex 2 having a more controlled shape and size can be produced.

The finely divided cellulose 22 contained in the complex 2 can control the particle size and shape by controlling the growth of the flat metal fine particles 21 to be produced. Further, in the resin molded body 1, the strength of the resin molded body can be improved, and dimensional stability can be imparted, and barrier properties can be imparted and improved.
From the viewpoints of improving transparency and strength, improving dimensional stability, imparting gas barrier properties, and controlling the shape of the flat metal fine particles 21 in the complex, it is preferable that the minor axis diameter of the finely divided cellulose 22 is sufficiently small.

The type of plant cellulose used as a raw material for the finely divided cellulose 22 is not particularly limited. As the raw material of the finely divided cellulose 22, for example, in addition to wood-based natural cellulose, cotton linter, bamboo, hemp, bagasse, kenaf and the like can be used. Further, as the raw material of the finely divided cellulose 22, for example, non-wood-based natural cellulose such as bacterial cellulose, squirrel cellulose, and baronia cellulose, and regenerated cellulose typified by rayon fiber and cupra fiber can also be used. Preferably, natural cellulose having a crystalline form I is desirable because it has high material properties such as mechanical properties, thermal properties, and chemical resistance.

The method for refining cellulose is not particularly limited, and examples thereof include a method for refining cellulose by using both chemical modification and mechanical treatment in addition to mechanical treatment with a grinder.
Bacterial cellulose can also be used as the micronized cellulose 22. Further, finely regenerated cellulose fibers obtained by dissolving various natural celluloses in various cellulose solvents and then electrolytically spinning may be used.
The method for chemically modifying cellulose is not particularly limited, but for example, an N-oxyl compound such as 2,2,6,6-tetramethyl-1-piperidin-N-oxyradic (hereinafter referred to as “TEMPO”) is used. Examples thereof include a method in which the existing oxidation treatment, dilute acid hydrolysis treatment, enzyme treatment and the like are used in combination with mechanical treatment to make the particles finer.

The finely divided cellulose 22 is preferably chemically modified finely divided cellulose. The chemically modified finely divided cellulose is not particularly limited, but for example, defibrating chemically modified cellulose such as carboxylated cellulose (hereinafter referred to as “oxidized cellulose”), carboxymethylated cellulose, and phosphate esterified cellulose. Can be obtained by. In the chemically modified finely divided cellulose, the introduced functional groups such as carboxy group, carboxymethyl group, and phosphoric acid group serve as a starting point in the formation of metal fine particles, and it is easy to control the shape and size of the complex.

Carboxymethylated cellulose can be obtained as a cellulose raw material by a known method. For example, an etherifying agent such as monochloroacetic acid and an alkali metal hydroxide such as sodium hydroxide and potassium hydroxide which are catalysts are added to a cellulose raw material, and a solvent whose main component is water or a lower alcohol such as methanol, ethanol or isopropyl alcohol. Obtained by reacting below. The carboxymethylated cellulose may have at least a part of glucopyranose carboxymethylated, and the degree of substitution of carboxymethyl cellulose is preferably 0.01 or more and 0.60 or less.

In particular, as shown in the method of Patent Document 2, in the oxidation reaction using an N-oxyl compound such as TEMPO, the 6th primary hydroxyl group of the glucopyranose unit of the cellulose molecular chain on the crystal surface has high selectivity. Oxidized cellulose is obtained by converting it into a carboxy group via an aldehyde group. Since an electrostatic repulsive force acts between the celluloses having a carboxy group introduced into the crystal surface in this way, the cellulose single nanofibers dispersed to the microfibril unit in an aqueous medium (hereinafter referred to as "CSNF"). .) Can be obtained. Therefore, it is easy to control the shape and size of the complex by using CSNF.
The oxidation reaction using the N-oxyl compound will be described in detail later.

By using this CSNF, it is possible to produce a complex 2 whose shape and size are sufficiently controlled. CSNF, which is fibrous and has a uniform minor axis diameter, is suitable for controlling the particle diameter and shape of the flat metal fine particles 21 in the composite 2. CSNF has regular carboxy groups on the fiber surface. This carboxy group is suitable for the production of the complex 2 because it is considered that the metal ion is coordinated and becomes the starting point for the formation of the complex 2 when the complex 2 is produced.

The viscosity characteristics of the finely divided cellulose 22 are preferably as follows. The 0.5% by mass dispersion (25 ° C.) of the finely divided cellulose 22 is 30 mPa · s or more and 2000 mPa · s or less when the shear rate is 1 s ^-1 , and 20 mPa · s or more and 200 mPa · s or more when the shear rate is 100 s ^-1 . -It is preferably s or less. More preferably, when the viscosity (25 ° C.) of the 0.5% by mass dispersion of the finely divided cellulose is 100 mPa · s or more and 1000 mPa · s or less when the shear rate is 1 s ^-1 , and the shear rate is 100 s ^-1 . It is 30 mPa · s or more and 80 mPa · s or less.

When the viscosity characteristic of the finely divided cellulose 22 is within the above range, the finely divided cellulose 22 has a low viscosity, so that it can be used at a high concentration and the composite 2 can be produced with high productivity. Further, when the viscosity characteristic is within the above range, the crystal structure and the surface structure are maintained, and the carboxy group which is the starting point of the composite with the metal fine particles and the crystal growth into the flat plate shape is regularly held, so that the crystal structure is stable. A composite 2 having a controlled shape can be manufactured. Further, if the viscosity characteristics are within the above range, the metal salt and the finely divided cellulose 22 can be uniformly mixed in the step b described later, and the reduction reaction can be uniformly promoted in the step c described later. ..

The finely divided cellulose 22 preferably has a minor axis number average shaft diameter of 1 nm or more and 50 nm or less, a major axis number average shaft diameter of 0.1 μm or more and 10 μm or less, and a minor axis number average shaft diameter of 1 nm or more and 10 nm. Hereinafter, it is more preferable that the number average shaft diameter of the long shaft is 0.2 μm or more and 2 μm or less.
If the number average shaft diameter of the minor axis of the micronized cellulose 22 is less than 1 nm, it is not possible to obtain a highly crystalline and rigid finely divided cellulose structure, and it is possible to obtain a complex 2 in which the size and shape are sufficiently controlled. It will be difficult. In addition, it becomes difficult to obtain a resin molded body 1 having good strength and dimensional stability.
On the other hand, when the number average shaft diameter of the minor axis of the finely divided cellulose 22 exceeds 50 nm, the viscosity of the dispersion liquid of the finely divided cellulose 22 becomes high and the operability deteriorates. It becomes difficult to uniformly mix the mixture, and in the step c described later, the reduction reaction cannot proceed uniformly, and it is difficult to obtain a complex whose size and shape are sufficiently controlled. Further, the transparency of the resin molded product 1 may be lowered, sufficient gas barrier properties may not be exhibited, and the strength may be lowered.
If the number average shaft diameter of the major axis of the finely divided cellulose 22 is less than 0.1 μm, it becomes difficult to obtain a complex 2 having a controlled shape and size. On the other hand, when the number average shaft diameter of the major axis of the finely divided cellulose 22 exceeds 10 μm, the viscosity of the dispersion liquid of the finely divided cellulose 22 becomes high and the operability deteriorates. It becomes difficult to uniformly mix the cellulose 22, and in the step c described later, the reduction reaction cannot proceed uniformly, and it is difficult to obtain the complex 2 whose size and shape are sufficiently controlled. In addition, it becomes difficult to mix the resin 11 and the complex-containing substance obtained by concentrating the complex from the complex dispersion liquid. Details of the complex-containing material will be described later.

The number average shaft diameter of the minor axis of the finely divided cellulose 22 is obtained as an average value obtained by measuring the minor axis diameter (minimum diameter) of 100 fibers by observation with a transmission electron microscope and observation with an atomic force microscope. On the other hand, the number average axis diameter of the major axis of the finely divided cellulose is obtained as an average value obtained by measuring the major axis diameter (maximum diameter) of 100 fibers by observation with a transmission electron microscope and observation with an atomic force microscope.

The measuring method for the minor axis diameter and the major axis diameter of the finely divided cellulose 22 is not particularly limited, but can be measured by, for example, the following method. A mixture of finely divided cellulose 22 dispersed in water so that the solid content concentration is in the range of 0.001 wt% or more and 0.01 wt% or less is developed on mica and naturally dried. After that, the minor axis diameter and the major axis diameter of the refined cellulose 22 can be confirmed (measured) by observing the refined cellulose 22 with a transmission electron microscope.

The crystallinity of the finely divided cellulose 22 is preferably 70% or more. If the crystallinity of the finely divided cellulose 22 is less than 70%, a rigid finely divided cellulose structure cannot be obtained, it becomes difficult to stably produce the composite 2, and the gas barrier property of the resin molded body 1 is sufficient. Instead, the effect of improving dimensional stability and the strength may decrease.

The amount of carboxy group in the refined cellulose 22 is preferably 0.1 mmol or more and 3.0 mmol or less, and more preferably 0.5 mmol or more and 2.0 mmol or less per 1 g of the dry weight of the refined cellulose 22.
When the amount of the carboxy group in the refined cellulose 22 is less than 0.1 mmol / g, the dispersibility is poor, and when it is 0.1 mmol / g or more, the dispersion stability is improved due to the electrostatic repulsion by the carboxy group. On the other hand, when the amount of carboxy groups in the refined cellulose 22 is 3.0 mmol / g or less, the crystal structure of the refined cellulose 22 is sufficiently maintained and the shape control performance is improved.

When the cellulose fibers are dispersed to the microfibril unit, the light transmittance at a wavelength of 660 nm is increased. In a dispersion having a solid content concentration of 1%, the finely divided cellulose 22 preferably has an optical path length of 1 cm and a wavelength of 660 nm and a light transmittance of 80% or more with reference to the dispersion medium. By using the highly transparent finely divided cellulose 22, the visibility of the contents is improved when the resin molded product is used as a packaging material.

The micronized cellulose 22 is not particularly limited, but one produced by the oxidation step and the miniaturization step shown below can be used (micronized cellulose manufacturing step).

(Oxidation process)
Examples of natural cellulose used as a raw material for the finely divided cellulose 22 include wood pulp such as mechanical pulp, chemical pulp, and semi-chemical pulp. Specifically, bleached and unbleached kraft wood pulp, hydrolyzed kraft wood pulp, sulfite wood pulp and the like, used paper, bacterial cellulose, baronia cellulose, squirrel cellulose, cotton cellulose, hemp cellulose and mixtures thereof are used. be able to. Further, either a substance obtained by physically or chemically treating these may be used. From the viewpoint of ease of material procurement and price, it is preferable to use various wood pulps as raw materials.

In the presence of the N-oxyl compound, as a method for oxidizing cellulose using an oxidizer, alcoholic primary carbon is selectively oxidized under relatively mild water-based conditions while maintaining the crystal structure of cellulose as much as possible. It is possible to do. Examples of the N-oxyl compound include TEMPO, 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-N-. Examples thereof include oxyl, 4-ethoxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-acetamide-2,2,6,6-tetramethylpiperidine-N-oxyl and the like. Among these, TEMPO is preferable.
The amount of the N-oxyl compound used may be any amount as long as it is used as a catalyst, and is not particularly limited. Usually, the amount of the N-oxyl compound used is about 0.01% by mass to 5.0% by mass with respect to the total solid content of the wood-based natural cellulose to be oxidized.

Examples of the method for oxidizing cellulose using an N-oxyl compound include a method in which natural wood-based cellulose is dispersed in water and subjected to an oxidation treatment in the presence of the N-oxyl compound. At this time, it is preferable to use a copolymer together with the N-oxyl compound. In this case, in the reaction system, the N-oxyl compound is sequentially oxidized by the copolymer to form an oxoammonium salt, and the oxoammonium salt oxidizes the cellulose. According to such an oxidation treatment, the oxidation reaction proceeds smoothly even under mild conditions, and the efficiency of introducing a carboxy group is improved. When the oxidation treatment is carried out under mild conditions, it is easy to maintain the crystal structure of cellulose.

Examples of the cooxidant include halogen, hypohalogenic acid, subhaloic acid and perhalogenic acid, or salts thereof, halogen oxides, nitrogen oxides, peroxides, etc., if it is possible to promote the oxidation reaction. , Any oxidizing agent can be used. Sodium hypochlorite is preferable as the copolymer because of its availability and reactivity.
The amount of the copolymer used may be any amount as long as it can promote the oxidation reaction of cellulose, and is not particularly limited. Usually, it is about 1% by mass to 200% by mass with respect to the total solid content of the wood-based natural cellulose to be oxidized.

Along with the N-oxyl compound and the copolymer, at least one compound selected from the group consisting of bromide and iodide may be further used in combination. As a result, the oxidation reaction of cellulose can proceed smoothly, and the efficiency of introducing a carboxy group can be improved.
As such a compound, sodium bromide or lithium bromide is preferable, and sodium bromide is more preferable from the viewpoint of cost and stability.
The amount of this compound used is not particularly limited as long as it can promote the oxidation reaction of cellulose. Usually, it is about 1% by mass to 50% by mass with respect to the total solid content of the wood-based natural cellulose to be oxidized.

The pH of the reaction system during the oxidation reaction of cellulose is preferably 9 to 11. When the pH is 9 or more, the reaction can proceed efficiently. It is known that when the pH range is out of the range, the oxidation efficiency of the N-oxyl compound is significantly reduced. In the above oxidation treatment, the pH in the reaction system is lowered due to the generation of carboxy groups as the oxidation progresses. Therefore, it is preferable to keep the pH of the reaction system at 9 to 11 during the oxidation treatment. Examples of the method of keeping the pH of the reaction system at 9 to 11 include a method of adding an alkaline aqueous solution according to the decrease in pH.
Examples of the alkaline aqueous solution include sodium hydroxide aqueous solution, lithium hydroxide aqueous solution, potassium hydroxide aqueous solution, ammonia aqueous solution, tetramethylammonium hydroxide aqueous solution, tetraethylammonium hydroxide aqueous solution, tetrabutylammonium hydroxide aqueous solution, and benzyltrimethylammonium hydroxide solution. Examples include organic alkalis such as aqueous solutions. Among these, an aqueous solution of sodium hydroxide is preferable from the viewpoint of cost and the like.

The reaction temperature of the oxidation reaction of cellulose is preferably 4 ° C. or higher and 50 ° C. or lower, and more preferably 30 ° C. or higher and 50 ° C. or lower.
The oxidation reaction itself with a normal N-oxyl compound proceeds sufficiently even in the region of 4 ° C. or higher and 50 ° C. or lower, but when the oxidation reaction is carried out in the temperature region of 30 ° C. or higher and 50 ° C. or lower, the crystal structure of the cellulose fiber is maintained. It has been found that the dispersion liquid of the finely divided cellulose 22 obtained as it is has a low viscosity. This is because the amorphous region exists periodically in the long axis direction of the cellulose microfibrils, so that the oxidation reaction by the N-oxyl compound proceeds to the amorphous region, and the generated glucuronic acid unit has a pH of 9 in the reaction temperature region. It is considered that this is because the fiber is unstable under the conditions of to 11 and is decomposed, and as a result, the fiber shortening progresses. If the reaction temperature exceeds 50 ° C., sodium hypochlorite self-decomposes due to a side reaction, so that the oxidation reaction itself is stopped.

The degree of oxidation in the oxidation treatment of cellulose can be appropriately set in consideration of the reaction temperature, the desired amount of carboxy groups, and the like. However, at least the amount of sodium hydroxide added in the oxidation reaction is preferably 1.0 mmol / g or more and 5.0 mmol / g or less per dry weight of the natural cellulose as a raw material. If the amount of sodium hydroxide added is less than 1.0 mmol / g, the amount of carboxy groups introduced will be small, and sufficient electrostatic repulsion between microfibrils required for dispersion as CSNF cannot be obtained. On the other hand, if the amount of sodium hydroxide added exceeds 5.0 mmol / g, decomposition occurs in areas other than the amorphous region, the microfibril surface structure is lost, and the yield before and after the oxidation treatment is significantly reduced.

The oxidation reaction with the N-oxyl compound can be stopped by adding a primary alcohol to the reaction system. At this time, it is preferable to keep the pH of the reaction system within the above range. As the primary alcohol to be added, low molecular weight primary alcohols such as methanol, ethanol and propanol are preferable in order to terminate the reaction quickly, and ethanol is particularly preferable from the viewpoint of safety of by-products produced by the reaction. ..

The reaction solution after the oxidation treatment may be subjected to the miniaturization step as it is, but in order to remove catalysts such as N-oxyl compounds, impurities and the like, the cellulose oxide contained in the reaction solution is recovered and washed with a washing solution. Is preferable. The recovery of cellulose oxide can be carried out by a known method such as filtration using a glass filter or a nylon mesh having a pore size of 20 μm. Distilled water is preferable as the cleaning liquid used for cleaning the oxidized cellulose.

(Miniaturization process)
The micronization step is a step of defibrating the oxidized cellulose by a slight mechanical treatment to obtain a dispersion liquid of the micronized cellulose 22.
In the method of refining cellulose, first, a solvent is added to the cellulose to suspend it.
The solvent is not particularly limited, but the same solvent as that for dispersing the finely divided cellulose 22 can be used, and among these, water is particularly preferable. If necessary, the pH of the suspension may be adjusted in order to improve the dispersibility of the cellulose and the finely divided cellulose 22 produced. Examples of the alkaline aqueous solution used for adjusting the pH include those similar to the alkaline aqueous solution described in the description of the oxidation step of cellulose oxide.

Subsequently, the suspension is subjected to a physical defibration treatment to refine the cellulose.
Physical defibration treatment includes, for example, high-pressure homogenizer, ultra-high pressure homogenizer, ball mill, roll mill, cutter mill, planetary mill, jet mill, attritor, grinder, juicer mixer, homomixer, ultrasonic homogenizer, nanogenizer, underwater facing collision. Such as mechanical processing. By performing such a physical defibration treatment on, for example, TEMPO-oxidized cellulose, the cellulose in the suspension is made finer, and a dispersion of CSNF having a carboxy group on the fiber surface can be obtained.

Since the finely divided cellulose 22 obtained as described above maintains the crystal structure, the complex 2 can be stably produced.
The obtained dispersion can be used as a reaction field for reducing and precipitating metal fine particles as it is or by diluting, concentrating, solvent substitution or the like as necessary.
If necessary, the dispersion liquid of the finely divided cellulose 22 may contain other components other than the components used for adjusting the cellulose and pH, as long as the effects of the present embodiment are not impaired. The other components are not particularly limited, and can be appropriately selected from known additives depending on the intended use. Specific examples of the other components include organometallic compounds such as alkoxysilane or their hydrolyzates, inorganic layered compounds, inorganic acicular minerals, defoaming agents, inorganic particles, organic particles, lubricants, and antioxidants. Examples thereof include agents, antistatic agents, ultraviolet absorbers, stabilizers, magnetic powders and the like. The complex 2 may be produced after mixing the aqueous dispersion component and the aqueous emulsion component with the micronized cellulose dispersion.

[Manufacturing method of complex 2]
The manufacturing step (complex manufacturing step) of the complex 2 is not particularly limited, but includes, for example, the following steps a, b, and c.
Step a is a step of preparing a finely divided cellulose-containing liquid by preparing a solution or a dispersion containing at least one kind of finely divided cellulose 22 and preparing a finely divided cellulose-containing liquid.
In step b, a solution or dispersion containing at least one kind of metal salt and at least one kind of finely divided cellulose 22 is prepared, and a metal salt and a finely divided cellulose-containing liquid are prepared. This is a liquid preparation process.
Step c is a reaction liquid preparation step of reducing metal ions in the metal salt and the finely divided cellulose-containing liquid to prepare a reaction liquid to obtain a complex dispersion liquid.

The finely divided cellulose 22 used for producing the complex is preferably chemically modified finely divided cellulose. Metal ions are reduced in a state where the metal ions are coordinated with the functional group introduced by chemical modification, and metal fine particles are generated from the metal ions as the base point, which facilitates compounding and shape control.

(Step a: Preparation step of micronized cellulose dispersion liquid)
In the method for producing the complex 2, in step a, at least one kind of finely divided cellulose dispersion is prepared.

The solid content concentration of the finely divided cellulose dispersion in at least one kind of finely divided cellulose dispersion is not particularly limited, but is preferably 0.01% by mass or more and 90% by mass or less, and is 0.1% by mass or more and 50% by mass. % Or less is more preferable.
If the solid content concentration of the finely divided cellulose dispersion is less than 0.01% by mass, it is difficult to control the shape of the complex 2. On the other hand, when the solid content concentration of the finely divided cellulose dispersion exceeds 90% by mass, the viscosity of the finely divided cellulose dispersion becomes high, and in step b (preparation step of preparing the metal salt and the finely divided cellulose-containing liquid), the metal salt and the fineness become fine. It becomes difficult to uniformly mix the modified cellulose 22 and it becomes impossible to uniformly proceed with the reduction reaction in the step c (reaction solution preparation step).

The solvent for dispersing the finely divided cellulose 22 is not particularly limited as long as the finely divided cellulose 22 is sufficiently dissolved or dispersed. From the viewpoint of environmental load, it is preferable to use water as the solvent.
From the viewpoint of the dispersibility of the flat metal fine particles 21 and the finely divided cellulose 22, it is preferable to use water or a hydrophilic solvent as the solvent. The hydrophilic solvent is not particularly limited, but alcohols such as methanol, ethanol and isopropanol are preferable.

The pH of at least one type of the finely divided cellulose dispersion is not particularly limited, but is preferably pH 2 or more and pH 12 or less.

(Step b: Preparation step of liquid containing metal salt and finely divided cellulose)
In the method for producing the complex 2, in step b, a solution or dispersion containing at least one kind of metal salt and at least one kind of finely divided cellulose 22 is prepared, and the metal salt and the finely divided cellulose-containing liquid are prepared. ..

The method for preparing a solution or dispersion containing at least one kind of metal salt and at least one kind of finely divided cellulose 22 is not particularly limited. For example, a solution or dispersion liquid containing at least one kind of finely divided cellulose 22 (micronized cellulose dispersion liquid) and a solution containing at least one kind of metal salt (metal salt-containing solution) are prepared, and the finely divided cellulose is prepared. It can be prepared by adding a metal salt-containing solution to the micronized cellulose dispersion while stirring the dispersion. Further, the solid metal salt may be added directly to the finely divided cellulose dispersion, or the finely divided cellulose dispersion may be added to the metal salt-containing solution.

The metal salt consists of silver nitrate, silver chloride, silver oxide, silver sulfate, silver acetate, silver nitrite, silver chlorate, gold chloride acid, sodium gold chloride, potassium gold chloride, platinum chloride, platinum oxide and platinum oxide. It is preferably at least one selected. One type of these metal salts may be used alone, or two or more types may be used in combination.

When preparing a metal salt-containing solution, the solvent used for the metal salt-containing solution is not particularly limited as long as the metal salt is sufficiently dispersed or dissolved.
From the viewpoint of environmental load, it is preferable to use water as the solvent.
From the viewpoint of the solubility of the metal salt, it is preferable to use water or a hydrophilic solvent as the solvent. The hydrophilic solvent is not particularly limited, but alcohols such as methanol, ethanol and isopropanol are preferable.
Further, the concentration of the metal salt in the metal salt-containing solution is not particularly limited.

The concentration of the metal salt in the metal salt and the finely divided cellulose dispersion is not particularly limited, but is preferably 0.002 mmol / L or more and 20.0 mmol / L or less. In particular, when CSNF is used as the finely divided cellulose 22, metal ions are coordinated with the carboxy groups existing on the fiber surface, so the concentration of the metal salt (concentration of the metal ions) is adjusted to be less than the amount of the carboxy group. Is preferable. If the concentration of the metal salt (concentration of metal ions) exceeds the amount of carboxy groups present on the surface of the micronized cellulose 22, CSNF may aggregate.

The solvent used for the metal salt and the finely divided cellulose-containing liquid is not particularly limited as long as the finely divided cellulose 22 is sufficiently dispersed or dissolved.
From the viewpoint of environmental load, it is preferable to use water as the solvent.
From the viewpoint of the dispersibility of the complex 2, it is preferable to use water or a hydrophilic solvent as the solvent. The hydrophilic solvent is not particularly limited, but alcohols such as methanol, ethanol and isopropanol are preferable.

The solid content concentration of the finely divided cellulose 22 in the metal salt and the finely divided cellulose dispersion is not particularly limited, but is preferably 0.01% by mass or more and 90% by mass or less, and is 0.1% by mass or more and 50% by mass or less. Is more preferable.
If the solid content concentration of the finely divided cellulose 22 is less than 0.01% by mass, it is difficult to control the shape of the complex 2. On the other hand, when the solid content concentration of the finely divided cellulose 22 exceeds 90% by mass, the viscosity of the finely divided cellulose dispersion becomes high, and it becomes difficult to uniformly mix the metal salt and the finely divided cellulose 22 in step b. In step c, the reduction reaction cannot proceed uniformly. When the composite 2 is used as a conductive material, it becomes difficult to sinter at a low temperature when the solid content concentration of the finely divided cellulose 22 becomes high, and a step of removing the finely divided cellulose 22 is required.

The solvent of the metal salt and the finely divided cellulose-containing liquid is not particularly limited as long as the finely divided cellulose 22 is sufficiently dissolved or dispersed.
From the viewpoint of environmental load, it is preferable to use water as the solvent.
From the viewpoint of the dispersibility of the flat metal fine particles 21 and the finely divided cellulose 22, it is preferable to use water or a hydrophilic solvent as the solvent. The hydrophilic solvent is not particularly limited, but alcohols such as methanol, ethanol and isopropanol are preferable.

The pH of the metal salt and the finely divided cellulose-containing liquid is not particularly limited, but is preferably pH 2 or more and pH 12 or less.
The temperature of the metal salt and the finely divided cellulose-containing liquid is not particularly limited, but is preferably 4 ° C. or higher and 100 ° C. or lower when water is used as the solvent.

(Step c: Reaction solution preparation step)
In the method for producing the complex 2, in the step c, the metal ions in the metal salt and the finely divided cellulose-containing liquid are reduced to prepare a reaction liquid to obtain a composite dispersion liquid.

The method for reducing the metal ions in the metal salt and the finely divided cellulose-containing liquid is not particularly limited, and a known method can be used. For example, a method using a reducing agent, ultraviolet rays, an electron beam, submerged plasma, or the like can be adopted. As the reducing agent used for the reduction of metal ions, a known reducing agent can be used.

Examples of the reducing agent include metal hydride-based, borohydride-based, borane-based, silane-based, hydrazine-based and hydrazide-based reducing agents. Generally, in the liquid phase reducing method, as the reducing agent, sodium borohydride, dimethylamine borane, sodium citrate, ascorbic acid, an alkali metal salt of ascorbic acid, hydrazine and the like are used.

The amount of the reducing agent added (concentration of the reducing agent) in the metal salt and the finely divided cellulose-containing liquid is not particularly limited, but should be equal to or higher than the concentration of the metal salt in the metal salt and the finely divided cellulose-containing liquid. Is preferable, and more preferably 0.002 mmol / L or more and 2000 mmol / L or less.
When the concentration of the reducing agent in the metal salt and the finely divided cellulose-containing liquid is equal to or less than the concentration of the metal salt in the metal salt and the finely divided cellulose-containing liquid, unreduced metal ions remain in the metal salt and the finely divided cellulose-containing liquid. Resulting in.

The method of adding the reducing agent when the reducing agent is used to reduce the metal ions in the metal salt and the finely divided cellulose-containing liquid is not particularly limited, but the reducing agent is previously dissolved or dispersed in a solvent such as water, and then the reducing agent is dissolved or dispersed in a solvent such as water. The solution or dispersion may be added to the metal salt and micronized cellulose-containing liquid.
The rate of addition of the reducing agent to the metal salt and the finely divided cellulose-containing liquid is not particularly limited, but it is preferable to add the reducing agent by a method that allows the reduction reaction to proceed uniformly.

The method for producing the complex 2 is not particularly limited, but it is preferable to include at least the above-mentioned steps a, b, and c. Other steps may be inserted between each step.

The complex 2 may be further coated with another metal or metal oxide to improve stability. The metal or metal oxide used for the coating is not particularly limited. Examples of such metals or metal oxides include gold, silver, copper, aluminum, iron, platinum, zinc, palladium, ruthenium, iridium, rhodium, osmium, chromium, cobalt, nickel, manganese, vanadium, molybdenum and gallium. , Metals such as aluminum, metal salts, metal complexes and alloys thereof, or oxides and double oxides.

Although not particularly limited, the complex may be fractionated and concentrated from the above-mentioned complex dispersion liquid, if necessary. If the amount of the solvent is excessive, the concentration of the resin composition described later becomes low, and for example, when producing the sheet-shaped resin molded product 1, energy is required to remove the solvent, resulting in poor productivity. By concentrating the composite 2, the solid content concentration of the resin composition is increased, and the amount of the solvent used for producing the resin molded product 1 is reduced, so that the resin molded product 1 can be efficiently produced. Examples of the fractionation / concentration method include centrifugation, gel filtration column, gel electrophoresis, freeze-drying, ultrafiltration, precipitation method and the like. A plurality of fractions and concentration methods may be combined. Hereinafter, the complex dispersion liquid and the complex 2 recovered by fractionation or concentration are referred to as a complex-containing substance.
When concentrating finely divided cellulose by centrifugation, it is necessary to concentrate it with an ultracentrifuge, but the flat silver / finely divided cellulose complex (complex) precipitates because a dense metal is bound to it. The coefficient becomes high, and it is possible to concentrate much more efficiently than in the case of the finely divided cellulose dispersion alone. Therefore, it is possible to reduce the proportion of the solvent in the resin composition, and it is possible to efficiently obtain the resin molded product 1.

[Resin 11]
The resin 11 is a polyvinyl alcohol (PVA) -based polymer. The PVA-based polymer is a resin produced by polymerizing a vinyl acetate monomer by a polymerization reaction and further saponifying it. As the PVA-based resin, it is preferable to use an unmodified PVA resin typified by a saponified product of a copolymer of vinyl acetate, but as long as the effect of the present embodiment is not impaired, the vinyl ester in vinyl acetate can be used. On the other hand, other vinyl compounds may be copolymerized. Further, a modified group may be partially introduced to impart functionality such as water resistance, solvent resistance, heat resistance, barrier property, and flexibility.

The degree of polymerization of the PVA-based polymer is not particularly limited, but those of 300 or more and less than 3000 are preferable, and those of 500 or more and less than 2500 are preferably used. When the degree of polymerization is less than 300, the interaction between PVA molecules is lowered, which may lead to deterioration of mechanical properties. If the degree of polymerization is greater than 3000, the viscosity of the coating liquid becomes too high, the film thickness of the resin molded product 1 becomes non-uniform, and it becomes difficult to remove the dispersion medium during the drying process, making it difficult to handle. Become.

The saponification degree of the PVA-based polymer is preferably 90 mol% or more and less than 100 mol%, and more preferably 95 mol% or more and less than 100 mol%. When the degree of saponification is less than 90 mol%, the hydrogen bond in the PVA-based polymer molecule due to the hydroxyl group is lowered, so that the motility of the molecule becomes active especially at a high temperature, and the molecule is easily deformed by heat. Further, it is difficult to obtain a saponification degree of 100 mol% in the manufacturing process.

[Crosslinking agent]
In the present embodiment, the selection of the cross-linking agent is particularly important in order to obtain the resin molded product 1 having the desired properties by cross-linking the PVA-based polymer. That is, the resin molded product containing no cross-linking agent and composed of the PVA-based polymer and the composite 2 exhibits high mechanical properties and a low linear expansion coefficient, but the resin molded product 1 having a cross-linked structure formed by further using a cross-linking agent. Can exhibit properties such as maintaining a low linear expansion coefficient at high temperatures and significantly improving water resistance. As the cross-linking agent used in the present embodiment, at least one that causes a cross-linking reaction with a PVA-based polymer can be used, and more preferably one that causes a cross-linking reaction with the finely divided cellulose 22 of the complex 2.

The cross-linking agent is a polymer having a molecular weight of 10,000 or more and less than 5,000,000. More preferably, a molecular weight of 50,000 or more and less than 1,000,000 is more preferably used. If the molecular weight is too small, it becomes difficult to form a three-dimensional structure together with the PVA-based polymer, and it becomes difficult to incorporate the refined cellulose 22 having a rigid shape into the crosslinked structure. In this case, it is difficult to realize water resistance and a low linear expansion coefficient under high temperature. Further, if the molecular weight is too large, it is difficult to dissolve uniformly and it becomes difficult to handle. In addition, the active site in the reaction system, that is, the frequency of access between the carboxylic acid and the hydroxyl group decreases, which causes a decrease in reactivity.

Examples of the cross-linking agent include oxazoline, divinyl sulfone, carbodiimide, dihydrazine, dihydrazide, epichlorohydrin and the like.
It is preferable to use a cross-linking agent capable of forming a cross-linked structure by using the PVA-based polymer and the hydroxyl group of the finely divided cellulose 22 as a foothold. Isocyanate, a methylol group, or a carboxyl group can be used as a functional group that exhibits good reactivity with a hydroxyl group.
Among them, a cross-linking agent having a carboxylic acid or a carboxylic acid anhydride is particularly preferable from the viewpoint of reactivity and stability. A strong crosslinked structure is formed by the reaction between the hydroxyl group of the PVA-based polymer or the cellulose fiber and the carboxylic acid contained in the crosslinking agent.
The cross-linking agent may be used alone or in combination of two or more.

[Manufacturing method of resin molded body 1]
Hereinafter, a method for manufacturing the resin molded body 1 will be described. The method for producing the resin molded body 1 is not particularly limited, but the resin composition can be coated on a base material or the like to form the resin molded body 1.
The resin composition contains at least the composite 2, the resin 11, and the cross-linking agent, and the resin 11 is a polyvinyl alcohol-based polymer, and the cross-linking agent is a polymer having a molecular weight of 10,000 or more and less than 5,000,000. Indicates a characteristic solution or dispersion.

The method for preparing the resin composition (resin composition preparation step) is as long as the complex-containing substance, the resin 11, and the cross-linking agent are sufficiently dissolved or dispersed in the solution within a range that does not cause any trouble. Not limited. They may be prepared and mixed in advance as a solution or a dispersion, respectively, a cross-linking agent and a complex-containing substance may be sequentially added to the solution of the PVA-based polymer, or the PVA-based polymer and the composite may be added to the cross-linking agent solution. A body-containing material may be added, or a PVA-based polymer or a cross-linking agent may be added in the dispersion of the complex-containing material to prepare a solution. The PVA-based polymer and the cross-linking agent may be heated in the preparation stage in order to improve the dispersibility in the solution. The complex-containing substance means a complex dispersion liquid and a concentrated concentrate of the complex.

Here, the solid content of the complex-containing material in the resin composition is preferably 0.1% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 30% by mass or less. When the solid content of the complex is less than 0.1% by mass, the characteristics such as sufficient low linear expansion property, water resistance, and high elastic modulus cannot be exhibited. On the other hand, if it exceeds 50% by mass, the brittleness becomes remarkable due to the rigidity of the finely divided cellulose 22, and the processability / moldability of the resin molded product deteriorates.
Further, the solid content of the metal contained in the resin composition is preferably 0.0001% by mass or more and 50.00% by mass or less, and preferably 0.01% by mass or more and 10% by mass or less. If the solid content of the metal is within this range, the light shielding function is fully exhibited.

The addition rate of the cross-linking agent is not limited as long as it does not impair the effect of the present embodiment, but the solid content in the resin composition is preferably 0.01% by mass or more and 20% by mass or less.
When a cross-linking agent having a carboxylic acid or a carboxylic acid anhydride is used, the number of functional groups of the carboxylic acid is preferably 1% or more and less than 50%, more preferably 5% or more, based on the number of functional groups of the hydroxyl groups in the resin composition. It can be suitably used when it is less than 20%. That is, when the amount of the cross-linking agent containing the carboxylic acid is too small, the cross-linking structure is not sufficiently developed and the effect of the cross-linking agent is reduced. If the amount is too large, the reaction does not proceed and the excess cross-linking agent may cause deterioration of the characteristics, and the hydrogen bonds between the hydroxyl groups in the resin molded product 1 are reduced, so that the characteristics of the species are deteriorated. In addition, additives may be included if necessary.

The solvent of the resin composition is not particularly limited, but preferably contains water from the viewpoint of the dispersibility of the complex 2. Further, a known solvent other than water may be contained. From the viewpoint of the dispersibility of the complex 2, it is preferable to use a hydrophilic solvent as the solvent. The hydrophilic solvent is not particularly limited, but alcohols such as methanol, ethanol and isopropanol are preferable. Among these solvents, ethanol is preferable.

The method for forming the resin molded body 1 using the resin composition thus prepared (resin molded body manufacturing step) is not particularly limited, but since the resin composition has fluidity, it is a resin group. The resin molded body 1 can be obtained by wet-coating and curing on a support such as on a material or a glass base material.
A known method can be used as the coating method. Specifically, bar coating method, dip coating method, spin coating method, flow coating method, spray coating method, roll coating method, gravure roll coating method, air doctor coating method, plaid coating method, wire doctor coating method, knife coating. A method, a reverse coating method, a transfer roll coating method, a microgravure coating method, a kiss coating method, a cast coating method, a slot orifice coating method, a calendar coating method, a die coating method and the like can be used.

The support that forms the resin molded body 1 is not particularly limited, and paper, a non-woven fabric, a glass base material, a plastic base material, or the like can be used according to the purpose.

The base material may be pretreated for the purpose of improving the wettability and adhesion of the support such as the base material to which the resin composition is applied. The pretreatment method is not particularly limited, and for example, an anchor layer may be formed in advance, or corona treatment, plasma treatment, frame treatment, or the like may be performed.

Next, a method for producing the resin molded body 1 will be described. For example, the resin composition is coated on the support by the above method and heated to remove excess solvent in the system, promote the cross-linking reaction by the cross-linking agent, and remove the resin composition on the support. Therefore, a resin molded body as a self-supporting film can be formed. The reactivity of the crosslinking reaction differs depending on the temperature at the time of heating, and the treatment is preferably performed in an atmosphere having a temperature of 100 ° C. or higher, preferably 120 ° C. or higher. However, if the treatment is carried out at 160 ° C. or higher, the decomposition of the cellulose fibers proceeds and the deterioration of the characteristics of the resin molded product causes yellowing. Therefore, the temperature is preferably less than 160 ° C.

As shown in FIG. 1, the resin molded body 1 thus formed includes at least a resin 11 having a crosslinked structure and a complex 2. The cross-linked structure is formed by a cross-linking agent.

Here, the solid content (solid content of the cellulose component and the metal component) of the complex-containing material (complex dispersion or complex concentrate) in the resin molded body 1 is 0.1% by mass or more and 50% by mass. It is preferably 10% by mass or more, and more preferably 30% by mass or less. When the solid content of the complex is less than 1% by mass, the characteristics such as sufficient low linear expansion property, water resistance, and high elastic modulus cannot be exhibited. On the other hand, if it exceeds 50% by mass, brittleness derived from the rigidity of the finely divided cellulose 22 becomes apparent, and the processability and moldability of the resin molded product deteriorates.
Further, the solid content of the metal contained in the resin composition is preferably 0.0001% by mass or more and 50.00% by mass or less, and preferably 0.01% by mass or more and 10% by mass or less. If the solid content of the metal is within this range, the light shielding function is fully exhibited.

The thickness T of the resin molded product 1 obtained in the present embodiment is preferably in the range of 1 μm or more and 500 μm or less, more preferably in the range of 10 μm or more and 200 μm or less, and particularly preferably in the range of 20 μm or more and 100 μm or less. When the thickness T is less than 1 μm, the strength of the resin molded product 1 becomes extremely weak, which makes it unsuitable for production. Further, if it exceeds 500 μm, the drying speed takes a very long time, the productivity is extremely lowered, and excess water remains inside the resin molded body 1, which is not preferable.
By using the complex-containing material, it is possible to obtain a resin composition at a high concentration more efficiently than by mixing finely divided cellulose alone with a resin to form a composite, and to reduce the energy required for solvent removal. This makes it possible to efficiently obtain a resin molded body having a thick film thickness.

Further, in the resin molded body 1 obtained by the present embodiment, since the composite body 2 is highly dispersed in the resin molded body 1, the absorption / reflection wavelength region of the composite body 2 by LSPR, that is, other than the vicinity of λmax described later, is used. Shows high transmittance. From the viewpoint of visibility of the contents, the resin molded product 1 preferably has a light transmittance of 50% or more at a wavelength of 660 nm. When the transmittance at a wavelength of 660 nm is 50% or more, the contents can be confirmed when the packaging material is used.

By using the above-mentioned method, it becomes possible to obtain the resin molded body 1 while maintaining the state in which the complex is highly dispersed, which has been difficult in the past, and the finely divided cellulose 22 bound to the complex 2 is excellent. It is possible to obtain a resin molded body 1 that makes the best use of its characteristics.

[Various additives]
In the present embodiment, the resin molded product 1 may contain a plurality of types of PVA-based polymers, and may contain resins other than the PVA-based polymers. Examples of the resin other than the PVA-based polymer include thermosetting resins and photocurable resins. If necessary, a cross-linking agent or a photopolymerization initiator may be contained.

The resin molded product 1 may contain various additives and various resins containing water-soluble polysaccharides, if necessary. For example, chemically modified cellulose, carrageenan, xanthan gum, guar gum, gum arabic, sodium alginate, agar, solubilized starch, glycerin, sorbitol, defoaming agent, water-soluble polymer, synthetic polymer and the like can be included. Various dyes and pigments, organic fillers, inorganic fillers and the like may be contained for the purpose of imparting design.

Further, in order to form a crosslinked structure for the purpose of improving water resistance and abrasion resistance, the resin molded body 1 may contain a plurality of types of various crosslinking agents. The cross-linking agent that forms a cross-linked structure by heating is not limited, and for example, oxazoline, divinyl sulfone, carbodiimide, dihydrazine, dihydrazide, epichlorohydrin, glioxal, organic titanium compound, organic zirconium compound and the like can be used. It is also possible to mix and use two or more of them. Among these, carbodiimide is preferable because it can efficiently form a crosslinked structure without applying a large amount of energy.

The resin molded body 1 can be mixed with known additives for the purpose of improving moldability, suppressing deterioration, improving dispersibility of the optical material, and the like. For example, it may contain a heat stabilizer, a stabilizing aid, a plasticizer, an antioxidant, a light stabilizer, a flame retardant, a lubricant, and an antistatic agent.

[Effect of this embodiment]
Since the resin molded body 1 contains the composite 2 having absorption in a specific wavelength region, it is preferable that the resin molded body 1 has a minimum wavelength (λmax) having a minimum transmittance in a wavelength region of 400 nm or more and 2500 nm or less, and 400 nm or more and 700 nm or less. It is more preferable to have λmax in the visible light region of.
In particular, when λmax is present in the visible light region of 400 nm or more and 600 nm or less, fading, deterioration, and odor generation of the contents can be suppressed, and the transmittance at 660 nm can be 50% or more, so that the packaging material can be used. When used, it is preferable because it has high visibility of the contents and the effect of suppressing discoloration / deterioration and odor generation of the contents becomes remarkable.
Further, the transmittance in λmax is preferably 70% or less, more preferably 50% or less.
When the transmittance at λmax and λmax is within this range, the effect of the complex 2 shields a specific wavelength, and when used as a packaging material, the effect of suppressing discoloration and deterioration of the contents and suppressing the generation of odor is enhanced. .. The method for measuring the transmission spectrum is not particularly limited, but the measurement can be performed by the following method. The reference was measured in the sky, and the light transmittance of the resin molded body 1 was measured from a wavelength of 220 nm to 2500 nm with a spectrophotometer UV-3600 (manufactured by Shimadzu Corporation). From the obtained light transmittance, the wavelength at which the light transmittance is minimized is defined as λmax (nm) of the resin molded product.

Further, the strength of the resin molded body 1 is improved by the effect of the composite body 2. It is preferable that the maximum strength of the resin molded product is 50 N / mm ² or more and the elongation at break is 10% or more.
The maximum strength and the elongation at break are not particularly limited, but can be measured by, for example, the following method. The resin molded body 1 is cut into strips with a width of 15 mm, and a small tabletop tester EZ-LX (manufactured by Shimadzu Corporation) is used, and the load cell is 1.000 N and the tensile speed is 5 mm / min. The elongation and strength in the long side direction can be detected while chucking both ends, and the tensile strength (N / mm ² ) and breaking elongation (%) can be measured. The resin molded product 1 is humidity-controlled in a constant temperature and humidity chamber at 23 ° C. and 47 to 50% RH at least 1 day before measurement, and the measurement is also performed in the same environment.

Further, the resin molded body 1 of the present embodiment has a lower linear expansion coefficient and higher dimensional stability. The linear expansion coefficient of the resin molded product 1 is preferably 100 × ^10-5 / K or less, and more preferably 50 × ^10-5 / K or less. When the linear expansion coefficient is in this range, the dimensional stability is high.
The linear expansion coefficient is not particularly limited, but can be measured by the following method. The resin molded body 1 is cut into strips with a length of 15 mm and a width of 4 mm, and the elongation in the long side direction when heated to 15 to 180 ° C at 5 ° C / min while chucking both ends with a tension of 50 mN is measured by a thermal machine. The linear expansion coefficient is calculated from the sample elongation from 140 ° C. to 160 ° C. above Tg by measurement using a target device TMA / SS-6000 (manufactured by Seiko Instruments).

The resin molded body 1 can impart gas barrier properties such as oxygen gas due to the effects of the complex 2 and the PVA-based polymer. It is preferable to evaluate the gas barrier property as follows. The oxygen permeability (cc / m ² / day) can be measured in an atmosphere of 30 ° C.-40% RH using an oxygen permeability measuring device (MOCON OX-TRAN 2/21 manufactured by Modern Control Co., Ltd.).

The resin molded body 1 is not particularly limited, but can be used, for example, as a packaging material for foods, pharmaceuticals, cosmetics, electronic members, and the like.

Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto.

<Example 1>
(Preparation of 1-1 sample)
(1-1-1 Production of Micronized Cellulose 22)
The reagents and materials used for the production of the refined cellulose 22 are shown below.
Cellulose: Bleached Kraft Pulp (Fletcher Challenge Canada "MACHENZIE")
TEMPO: Commercial product (manufactured by Tokyo Chemical Industry Co., Ltd., 98%)
Sodium hypochlorite: Commercial product (manufactured by Wako Pure Chemical Industries, CL: 5%)
Sodium bromide: Commercial product (manufactured by Wako Pure Chemical Industries, Ltd.)

70 g of softwood kraft pulp was suspended in 3500 g of distilled water to prepare a suspension. To this suspension, a solution prepared by dissolving 0.7 g of TEMPO and 7 g of sodium bromide in 350 g of distilled water was added, and the mixture was cooled to 20 ° C.
450 g of a sodium hypochlorite aqueous solution having a density of 1.15 g / mL and 2 mol / L was added dropwise to this solution to initiate an oxidation reaction. The temperature in the system during the reaction was always kept at 40 ° C. In addition, although the pH in the system decreased during the reaction, the pH was kept at 10 by sequentially adding a 0.5 N aqueous sodium hydroxide solution.
When the sodium hydroxide reached 3.0 mmol / g with respect to the mass of cellulose, an excess amount of ethanol was added to stop the reaction.
Then, after filtering the mixture after the reaction with a glass filter, washing with a sufficient amount of water and filtration were repeated to obtain oxidized cellulose.

1 g of oxidized cellulose obtained by TEMPO oxidation was dispersed in 99 g of distilled water.
Then, the dispersion liquid containing the oxidized cellulose was subjected to a miniaturization treatment using a high-pressure homogenizer to obtain a finely divided cellulose aqueous dispersion having a content of the finely divided cellulose 22 of 1% by mass.

(1-1-2 Production of Complex 2)
Subsequently, 250 mg of silver nitrate was dissolved in 50 mL of distilled water to prepare an aqueous silver nitrate solution.
250 mg of sodium borohydride was dissolved in 50 mL of distilled water to prepare an aqueous solution of sodium borohydride.
0.2 L of the above-mentioned finely divided cellulose aqueous dispersion was placed in a container, and 10 g of an aqueous silver nitrate solution was added at room temperature (25 ° C.) while stirring with a stirring blade to prepare a dispersion containing the finely divided cellulose and silver nitrate. Subsequently, an aqueous solution of sodium borohydride was added to the dispersion liquid containing the finely divided cellulose 22 and silver nitrate and reacted to produce a complex dispersion liquid. The complex in the obtained complex dispersion is referred to as complex A.

(1-1-3 Recovery of complex content)
The above complex A dispersion is placed in a 200 mL centrifuge tube, diluted, centrifuged at 10,000 × g, and the precipitated complex is recovered to obtain a complex A-containing product having a solid content concentration of 10% by mass. Obtained.

(1-1-4 Preparation of Resin Composition and Resin Molded Body 1)
(Preparation of 1-1-4-1 resin composition)
PVA (PVA-117 manufactured by Kuraray, average degree of polymerization 1,700, saponification degree 99.0 mol%) and methyl vinyl ether maleic anhydride copolymer (International Specialty Products GANTREZ AN119, average molecular weight 130,000) as a cross-linking agent. ) Was dissolved in hot water. The PVA, the complex, and the cross-linking agent were mixed in this order so that the solid content weight ratio was 82:10:13 to obtain a resin composition having a solid content concentration of 15% by mass. The solid content of silver in the resin composition was 0.05% by mass.

(1-1-4-2 Preparation of Resin Molded Body I)
The prepared above solution is applied to a PET film (Lumilar T60-75 μm: Toray) with an applicator, dried in an oven at 120 ° C. for 10 minutes, and then the PET film is peeled off to form a 30 μm thick resin molded body I. Was produced.

(Preparation of 1-1-4-3 Resin Molded Product II)
The prepared above solution was corona-treated with a PET film (E5102-25 μm: Toyobo), coated with a bar coater, and dried in an oven at 120 ° C. for 10 minutes to prepare a resin molded product II having a thickness of 2 μm. ..

(1-2 procedure)
For the obtained oxidized cellulose and finely divided cellulose, the amount of carboxy group, crystallinity, number average shaft diameter of the long axis, light transmittance and rheology were measured and calculated as follows.

(1-2-1 Measurement of carboxy group amount)
For the oxidized cellulose before the dispersion treatment, the amount of carboxy group was calculated by the following method.
0.2 g of dried cellulose oxide in terms of dry weight was taken in a beaker, and 80 mL of ion-exchanged water was added.
To this, 5 mL of a 0.01 mol / L sodium chloride aqueous solution was added, and 0.1 mol / L hydrochloric acid was added while stirring to adjust the pH to 2.8 as a whole.
Using an automatic titrator (trade name: AUT-701, manufactured by DKK-TOA CORPORATION), a 0.1 mol / L sodium hydroxide aqueous solution was injected therein at 0.05 mL / 30 seconds, and the conductivity was changed every 30 seconds. The pH value was measured and the measurement was continued until pH 11.
From the obtained conductivity curve, the titration amount of sodium hydroxide was determined, and the content of the carboxy group was calculated.

(1-2-2 Calculation of crystallinity)
The crystallinity of TEMPO-oxidized cellulose was calculated.
For TEMPO-oxidized cellulose, X-rays were performed in the range of 5 ° ≤ 2θ ≤ 35 ° under the condition of X-ray output: (40 kv, 40 mA) using a sample horizontal multipurpose X-ray diffractometer (trade name: UltimaIII, manufactured by Rigaku). The line diffraction pattern was measured. Since the obtained X-ray diffraction pattern is derived from the cellulose type I crystal structure, the crystallinity of TEMPO-oxidized cellulose was calculated by the following method using the following formula (2).
Crystallinity (%) = [(I22.6-I18.5) /I22.6] × 100 ... (2)
However, I22.6 is the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) in X-ray diffraction, and I18.5 is the diffraction of the amorphous portion (diffraction angle 2θ = 18.5 °). Indicates strength.

(1-2-3 Calculation of number average shaft diameter of major axis of finely divided cellulose)
Using an atomic force microscope, the number average shaft diameter of the major axis of the finely divided cellulose was calculated.
First, the aqueous dispersion of finely divided cellulose was diluted to 0.001%, cast 20 μL each on a mica plate, and air-dried.
After drying, the shape of the finely divided cellulose was observed in the DFM mode using an atomic force microscope (trade name: AFM5400L, manufactured by Hitachi High-Technologies Corporation).
The number average shaft diameter of the major axis of the finely divided cellulose was determined as the average value by measuring the major axis diameter (maximum diameter) of 100 fibers from the observation image by the atomic force microscope.

(1-2-4 Measurement of light transmittance of finely divided cellulose aqueous dispersion)
The light transmittance of the finely divided aqueous cellulose dispersion was measured.
Water is put in one of the quartz sample cells as a reference, and a finely divided cellulose aqueous dispersion is put in the other so that bubbles do not get mixed in. It was measured with a meter (trade name: NRS-1000, manufactured by Nippon Spectroscopy Co., Ltd.).

(1-2-5 rheology measurement)
The rheology of the dispersion liquid of 0.5% by mass of the finely divided cellulose was measured with a rheometer (trade name: AR2000ex, manufactured by TA Instruments) on a cone plate with an inclination angle of 1 °.
The temperature of the measuring unit was adjusted to 25 ° C., and the shear viscosity was continuously measured from 0.01 s ^-1 to 1000 s ^-1 . Table 1 shows the shear viscosities when the shear rates are 1s ^-1 and 100s ^-1 .

(1-3 result)
The evaluation results are shown in Table 1, FIG. 8 and FIG. FIG. 8 is a diagram showing the results of measuring the transmittance of the micronized cellulose aqueous dispersion of Example 1. FIG. 9 is a diagram showing the evaluation results of the viscosity characteristics of the micronized cellulose aqueous dispersion of Example 1.
The results of Tables 1, 8 and 9 show that it was possible to produce finely divided cellulose having high crystallinity, high transmittance in the visible light region, and low viscosity.

Next, a total of 12 types of samples of the resin molded product produced in Example 1 were combined with 6 types of additional examples (Examples 2 to 7) and 5 types of comparative examples (Comparative Examples 1 to 5). A sample of the resin molded product was prepared. After explaining the 12 types of samples, the results of the experiments performed on each sample will be described. Table 2 shows the preparation conditions for the sample of the resin molded product 1.
FIG. 10 is a scanning transmission electron microscope (STEM) image of the complex of Example 1.
FIG. 11 is a scanning transmission electron microscope (STEM) image of the complex of Example 5.
FIG. 12 is a scanning transmission electron microscope (STEM) image of the complex of Example 6.

(Preparation of 2-1 sample)
<Example 2>
Resin molded bodies I and II were prepared under the same conditions as in Example 1 except that the solid content weight ratio of PVA, the complex and the cross-linking agent was adjusted to 78: 5: 13 in this order.

<Example 3>
Resin molded bodies I and II were prepared under the same conditions as in Example 1 except that an isobutylene maleic anhydride copolymer (Isovan 110 manufactured by Kuraray Co., Ltd., average molecular weight 170,000) was used as a cross-linking agent.

<Example 4>
Resin molded bodies I and II were prepared under the same conditions as in Example 1 except that PVA (PVA-105 manufactured by Kuraray, average degree of polymerization 500, saponification degree 99.0 mol%) was used.

<Example 5>
In the complex preparation step, resin molded bodies I and II were prepared under the same conditions as in Example 1 except that the complex B-containing material prepared with the addition amount of the silver nitrate aqueous solution as 5.0 g was used.

<Example 6>
In the complex preparation step, the resin molded bodies I and II were prepared under the same conditions as in Example 1 except that the complex C-containing material prepared by setting the addition amount of the silver nitrate aqueous solution to 2.5 g was used.

<Example 7>
Resin molded products I and II were prepared under the same conditions as in Example 1 except that maleic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was used as a cross-linking agent.

<Comparative Example 1>
Resin molded bodies I and II were prepared under the same conditions as in Example 1 except that the complex A-containing material was not added to the resin composition and the solid content weight ratio of PVA117 and AN119 was set to 86:14 in this order. did.

<Comparative Example 2>
Resin molded products I and II were prepared under the same conditions as in Comparative Example 1 except that maleic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was used as a cross-linking agent.

<Comparative Example 3>
Resin molded bodies I and II were prepared under the same conditions as in Comparative Example 1 except that an isobutylene maleic anhydride copolymer (Isovan 600 manufactured by Kuraray Co., Ltd., average molecular weight 6,500) was used as a cross-linking agent.

<Comparative Example 4>
Resin molded products I and II were prepared under the same conditions as in Comparative Example 1 except that a titanium lactate chelate (TC-310 manufactured by Matsumoto Fine Chemical Co., Ltd.) was used as a cross-linking agent.

<Comparative Example 5>
Resin molded products I and II were prepared as PVA under the same conditions as in Comparative Example 1 except that PVA-217 (average polymerization degree 1,700, saponification degree 89.0 mol%) and others.

(2-2 procedure)
The carboxy group amount, crystallinity, number average shaft diameter of the long axis, light transmittance and rheology were measured and calculated for the resin molded bodies I and II prepared under the conditions shown in Table 2 as follows. rice field.

(2-2-1 measurement of λmax of complex)
The light transmittance was measured for the contents of the complex A to the complex C of Examples 1 to 7.
A sample or a reference was placed in a sample cell made of quartz, and the light transmittance from a wavelength of 220 nm to 1300 nm at an optical path length of 1 cm was measured with a spectrophotometer UV-3600 (manufactured by Shimadzu Corporation). The complex-containing substance was appropriately diluted with water and placed in a quartz cell so as not to contain air bubbles for measurement. From the obtained light transmittance, the wavelength at which the light transmittance was minimized was defined as λmax (nm) of the dispersion liquid.

(2-2-2 Observation of products)
After appropriately diluting the content of the complex C from the complexes A of Examples 1 to 7, casting on a copper grid with a support film and air-drying, a scanning electron microscope (trade name: S-4800, Hitachi High-Technologies) Complex A to Complex C of Examples 1 to 7 were observed in STEM mode using (manufactured by the same company).

(2-2-3 tensile characteristics)
The obtained resin molded body I was cut into strips having a width of 15 mm, and the evaluation unit 50 mm was used under the conditions of a load cell of 1.000 N and a tensile speed of 5 mm / min using a small tabletop tester EZ-LX (manufactured by Shimadzu Corporation). Elongation and strength in the long side direction were detected while chucking both ends at intervals, and maximum strength (N / mm ² ) and breaking elongation (%) were measured. The resin molded product was humidity-controlled in a constant temperature and humidity chamber at 23 ° C. and 47 to 50% RH at least 1 day before the measurement, and the measurement was also performed in the same environment.

(2-2-4 linear expansion coefficient)
The resin molded body I is cut into strips with a length of 15 mm and a width of 4 mm, and the elongation in the long side direction when heated to 15 to 180 ° C at 5 ° C / min while chucking both ends with a tension of 50 mN is measured by a thermal machine. The linear expansion coefficient was calculated from the linear expansion coefficient of 20 ° C. to 40 ° C. and the sample elongation of 140 ° C. to 160 ° C. of Tg or more by measurement using a target device TMA / SS-6000 (manufactured by Seiko Instruments).

(2-2-5 water dissolution test)
A water elution test was conducted to evaluate the water resistance. For the resin molded product I, four samples cut into a square shape of 50 mm square were preliminarily dried at 100 ° C. for 3 hours. This was immersed in a sample bottle containing water, stored in an oven at 40 ° C. for 2 days, and then dried. The change in dry weight before and after immersion in water was calculated as the water insolubilization rate. The water was changed twice during the test period.

(Measurement of light transmittance 2-2-6)
The reference was measured in the sky, the light transmittance of the resin molded body I was measured from 220 nm to 2500 nm with a spectrophotometer UV-3600 (manufactured by Shimadzu Corporation), and the wavelength at the minimum value of the transmittance was λmax. The value of the transmittance at the wavelength of 660 nm was obtained.

(2-2-7 gas barrier property)
The oxygen gas barrier property of the resin molded product II was measured using MOCON. The oxygen permeability (cc / m ² / day) was measured in an atmosphere of 30 ° C.-40% RH using an oxygen permeability measuring device (MOCON OX-TRAN 2/21 manufactured by Modern Control Co., Ltd.).

(2-2-8 Oxidation degree measurement)
In order to use the resin molded product II as a packaging material, a heat seal layer is attached to the coating layer side of the resin molded product II via a laminating adhesive layer by a dry lamination method, and cured at 50 ° C. for 4 days. , A gas barrier film for packaging materials was prepared. A linear low-density polyethylene film (TUX-FCS, manufactured by Tosero Co., Ltd.) with a thickness of 50 μm is used as the heat seal layer, and a two-component curable polyurethane system is used as the adhesive for forming the adhesive layer for lamination. An adhesive for laminating (A515 / A50, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) was used. The adhesive was applied onto the coating layer by a gravure coating method so that the amount of the adhesive applied after drying was 4.0 g / m ² .
Using the packaging material obtained as described above, a pouch having an inner diameter of 200 × 200 mm was prepared and filled with 50 g of potato chips. The prepared pouch was stored at a temperature of 35 ° C. for 20 days under a light irradiation condition of 1500 LX under a white fluorescent lamp.
Potato chips after storage for 20 days were crushed, and the oxide value (POV) was measured using 5.0 g of ether-extracted fat and oil according to the Lea method.
The evaluation was carried out as follows. POV after 20 days,
If it is 0 meq / kg or more and 60 meq / kg or less, "◎"
If it exceeds 60 meq / kg and is 80 meq / kg or less, "○"
When it exceeds 80 meq / kg, it is set as "x".

(2-3 result)
Table 3 shows the measurement results of λmax for the complex A, the complex B, and the complex C prepared in Examples 1 to 7.
Table 4 shows the results of evaluating the mechanical properties, linear expansion coefficient, water insolubilization rate, light transmittance, oxygen permeability, and oxidation degree of the resin molded bodies I and II produced under the conditions shown in Table 2. ..
In Examples 1 to 6, excellent mechanical properties, dimensional stability, water resistance, and gas barrier properties were shown. In addition, it was confirmed that the oxidative deterioration of the contents was suppressed and the light beam was shielded by the complex. However, the light transmittance at 660 nm is high, and the contents can be visually confirmed. In Example 7, oxidative deterioration of the contents was suppressed, but the mechanical properties were not so good, the linear expansion coefficient at high temperature was high, and the water insolubilization rate was relatively low. Comparative Example 1 showed excellent mechanical properties, water resistance, and gas barrier properties, but oxidation of the contents was confirmed. In Comparative Examples 2 to 5, the deterioration of the contents was confirmed because the linear expansion coefficient was particularly high at high temperature and the light shielding property was not provided.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. It is possible to add, omit, replace, and make other changes to the configuration without departing from the spirit of the present invention.

Since it has the property of stably absorbing or reflecting a specific wavelength range over a long period of time and has a gas barrier property, it is possible to prevent oxidation of the contents by oxygen gas, etc., discoloration and deterioration of the contents by light, and generation of odor. It is possible to provide a resin molded body having high water resistance, high strength, good dimensional stability, and antibacterial property, a method for producing the same, and a resin composition used for producing the resin molded body. Using the resin molded body 1, packaging materials for foods, pharmaceuticals, cosmetics, and electronic members can be easily produced.

1 Resin molded body 2 complex (flat metal / micronized cellulose complex)
11 Resin 21 Flat metal fine particles 22 Finely divided cellulose 22a Part of finely divided cellulose (one end)
22b Part of finely divided cellulose (the other end)
23 Front side 24 Back side

Claims (15)

With resin
A complex containing flat metal fine particles and finely divided cellulose is provided.
The resin is a polyvinyl alcohol-based polymer and is
The composite is composited with the flat metal fine particles and at least one or more of the finely divided celluloses, and at least a part or all of each of the finely divided celluloses is incorporated into the flat metal fine particles. At least a part of the finely divided cellulose is composited so as to be exposed on the surface of the flat metal fine particles, and at least a part of the hydroxy group of the finely divided cellulose and the hydroxy group of the resin are methyl. It is crosslinked by a cross-linking agent selected from the group consisting of vinyl ether anhydrous maleic acid copolymer, isobutylene anhydrous maleic acid copolymer, and maleic acid .
Resin molded body. The cross-linked structure is formed by a cross-linking agent, and the cross-linking agent is a polymer having a weight average molecular weight of 10,000 or more and less than 5,000,000.
The resin molded product according to claim 1. The resin molded product according to claim 1 or 2, wherein the polyvinyl alcohol-based polymer has a saponification degree of 90 mol% or more and less than 100 mol%. The resin molded product according to any one of claims 1 to 3, wherein the complex content is 0.1% or more and 50% or less in terms of weight. The resin molded product according to any one of claims 1 to 4, wherein the breaking strength is 50 N / mm2 or more and the breaking elongation is 10% or more. The resin molded product according to any one of claims 1 to 5, wherein the linear expansion coefficient is 100 × 10-5 / K or less. The resin molded product according to any one of claims 1 to 6, which has a minimum wavelength having a minimum transmittance in a wavelength region of 400 nm or more and 700 nm or less in a transmittance spectrum. The average value of the thickness h of the flat metal fine particles is in the range of 1 nm or more and 50 nm or less.
The average value of the particle diameter d is in the range of 2 nm or more and 1000 nm or less.
The resin molded body according to any one of claims 1 to 7, wherein the average value of the particle diameter d is at least twice the average value of the thickness h of the flat metal fine particles. The resin molded body according to any one of claims 1 to 8, wherein the metal or metal compound constituting the flat metal fine particles contains at least one of gold, silver, and copper. The finely divided cellulose is fibrous and has a minor axis number average shaft diameter of 1 nm or more and 50 nm or less, and a major axis number average shaft diameter of 0.1 μm or more and 10 μm or less. The resin molded body according to item 1. The resin molded product according to any one of claims 1 to 10, wherein the OH group at the C6 position of at least a part of glucopyranose is selectively oxidized in the finely divided cellulose. The micronized cellulose has a minor axis number average shaft diameter of 1 nm or more and 10 nm or less, a major axis number average shaft diameter of 0.2 μm or more and 2 μm or less, and a carboxy group amount of 0.1 mmol / g or more and 3.0 mmol /. less than or equal to g
The resin molded product according to any one of claims 1 to 11. The resin molded product according to any one of claims 1 to 12, wherein the thickness thereof is within the range of 1 μm or more and 500 μm or less. Miniaturized cellulose manufacturing process and
Complex fabrication process and
Resin composition preparation process and
With a resin molded body manufacturing process,
A method for producing a resin molded body according to any one of claims 1 to 12, wherein the resin molded body is formed on a support by wet coating. With resin
A complex containing flat metal fine particles and finely divided cellulose,
With a cross-linking agent,
The resin is a polyvinyl alcohol-based polymer.
The cross-linking agent is a cross-linking agent selected from the group consisting of a methyl vinyl ether maleic anhydride copolymer, an isobutylene maleic anhydride copolymer, and a maleic acid .
The composite is composited with the flat metal fine particles and at least one or more finely divided cellulose, and at least a part or all of each of the fined cellulose is incorporated into the flat metal fine particles. At least a part of the finely divided cellulose is composited so as to be exposed on the surface of the flat metal fine particles.
Resin composition.

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