JP2018176583A - Laminate having adhesive reinforcement layer and production method of laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate having high strength, rigidity and impact resistance by laminating a reinforcement layer on a substrate made of glass, resin, or metal.SOLUTION: A laminate that is obtained by coating, adhering and crosslinking treating an adhesive reinforcement layer composition in which an unmodified cellulose nano-fiber, a dispersant, an aqueous or water dispersible crosslinkable resin, and a crosslinking agent (however, it is not necessary when a crosslinkable resin is self-crosslinkable) on an adhesion surface of a base and has high impact resistance and small damage due to bending and flexure, and is difficult to be cracked under stress application. Preferably, a laminate having a reinforcement layer made of a composition in which a crosslinkable resin of the reinforcement layer is made of a composition containing one kind or more with selected from copolymers with one kind or more of ethylenic double bond-compound selected from vinyl alcohol, vinyl acetate, vinyl butyral, acrylic acid, methacrylic acid and ethylene and/or derivatives thereof, or one kind or more selected from a water or alcohol-soluble modified polyamide resin, a crosslinkable copolymer polyamide, or an aqueous epoxy resin.SELECTED DRAWING: None

Description

  The present invention relates to a laminate having a substrate layer and a reinforcing layer, which is excellent in strength, rigidity and impact resistance, and is resistant to cracking.

Conventionally, glass has been used as a window for checking the inside of industrial machinery such as mixers and brabenders, and a front window, a rear window, and a sunroof of transportation facilities such as cars, ships, and aircraft. In recent years, a strong transparent plastic such as polycarbonate or acrylic resin has been used for the purpose of weight reduction, but the strength and impact resistance are not sufficient, and may be broken during use if a large force is applied.
If the inspection window material is made thicker in order to prevent cracks that occur during use, it not only increases the weight but also makes it difficult or expensive to manufacture. Moreover, laminating | stacking several base materials, apply | coating an adhesive agent in-between | in-the-meantime, and making it a laminated body is also performed.
Alternatively, most of the area of the inspection window is made of metal such as stainless steel or aluminum, and a glass or transparent resin inspection window is installed only in a part of the area, but the field of vision for inspection is narrow. It becomes difficult to observe the entire inside.
In addition, if acrylic resin is used for the inspection window, the plasticizer etc. added to the acrylic resin will elute, and it is not suitable as a material of the inspection window of the machine for food.
Cellulose nanofibers are obtained by removing fibers consisting of nano-sized cellulose crystals from plant pulp by mechanical disintegration or chemical oxidation treatment, and in recent years have made use of their high strength, elastic modulus, etc. to make resin materials. There are many attempts to reinforce it.

    Patent Document 1 proposes a display window protection plate for a portable terminal, which is coated with a curable paint on a transparent resin material and is resistant to cracking when pressed. That is, abrasion resistance is provided by apply | coating the curable paint which added electroconductive fine particles to transparent substrates, such as a methacrylic resin and polycarbonate resin.

    Patent Document 2 is composed of a glass film, a transparent resin layer, and a transparent reinforcing layer for bonding the glass film and the transparent resin layer, and the glass film / transparent reinforcing layer / transparent resin layer / transparent reinforcing layer / glass film 5 Although a film laminate having a layered structure is disclosed, the improvement in strength and impact resistance by the adhesive resin layer is not mentioned.

    Patent Document 3 discloses a glass resin laminate having a laminated structure of at least three or more layers consisting of a reinforcing layer for bonding a glass sheet layer and a resin layer, but the strength and impact resistance of the laminate by the adhesive resin layer There is no mention of the improvement of the cracking resistance.

    Patent Document 4 describes an attempt to use cellulose nanofibers for reinforcing a thermosetting resin or a thermoplastic resin.

JP, 2008-36927, A JP, 2014-65169, A JP, 2014-12373, A Patent No. 3641690

In Patent Document 1, conductive fine particles such as fine particles of antimony oxide are added to a curable film made of a polyfunctional methacrylate compound, and after being applied to a substrate such as methacrylic resin, it is cured by irradiation with active energy rays, A curable film having scratch resistance is obtained.
In the document, the strength and the cracking resistance depend on the material of the base material itself, and the reinforcement by the coating layer is not mentioned.

Patent Document 2 is used to protect an internal exhibit or product while allowing a viewer to appreciate the internal exhibit or product represented by a frame, a show window, a showcase, etc. A transparent resin sheet is adhered to a glass sheet which is a brittle material, which is described for a transparent laminate, thereby preventing breakage or damage of the contents due to scattering of glass fragments when a crack is generated due to physical impact. It is to do.
A glass plate is used with a glass plate thickness of 300 μm or less because it becomes heavy. However, it is an internal observation window of an industrial machine that is repeatedly stressed or receives a large impact force, or a front window of an automobile etc. And can not be used as a sunroof.

  Patent Document 3 relates to a glass plate used for a vehicle, a frame, a flat panel display, a glass substrate of a device such as a solar cell, an electronic paper, a cover glass such as an organic EL illumination, a pharmaceutical package, etc. The resin layer is adhered via an adhesive layer. In this case, by setting the spectral transmittance in the wavelength range of 430 to 680 nm in the adhesive layer to 90% or more, the image seen through the glass laminate is prevented from becoming yellowish, and the thickness of the glass sheet used is Since the thickness of the adhesive layer is 100 to 300 μm and the thickness of the adhesive layer is 50 to 800 μm, there is a problem that it can not be used as a protective cover for internal observation windows such as industrial machines that are repeatedly stressed or subjected to large impact forces. The

  Although Patent Document 4 describes an attempt to use cellulose nanofibers for reinforcing a thermosetting resin or a thermoplastic resin, a sheet of cellulose nanofibers prepared in advance is impregnated with a liquid resin, laminated, and compression molded. Only the method is disclosed, and it is not applicable to various commonly used resin molding means such as injection molding, extrusion molding, casting and the like.

  The object of the present invention is to laminate a substrate layer by applying a reinforcing layer having a thickness of 0.005 to 1 mm to the substrate layer when laminating the sheet layer, film, plate or the like. The crosslinking treatment is to provide a laminate having high strength, rigidity and impact resistance.

The present invention is constituted by the following [1] to [7].
[1] A laminate comprising a base layer comprising a single layer or two or more layers, and a reinforcing layer, wherein the reinforcing layer is a synthetic resin containing cellulose nanofibers.
[2] The laminate according to [1], wherein the reinforcing layer is a cured layer obtained by crosslinking and curing a composition containing a water-soluble or water-dispersible crosslinkable resin and a dispersant.
[3] The laminate according to [1] or [2], wherein the composition containing the crosslinkable resin is a composition containing a crosslinking agent, or the crosslinkable resin is a self-crosslinkable composition.
[4] The crosslinkable resin of the reinforcing layer is vinyl alcohol and at least one ethylenic double bond-containing compound selected from the group consisting of vinyl acetate, vinyl butyral, acrylic acid, methacrylic acid, and ethylene. And / or a derivative thereof, or a composition comprising at least one selected from the group consisting of a derivative thereof, or a modified polyamide resin soluble in water or alcohol, a cross-linked copolymer polyamide, or a water-soluble epoxy resin And the laminated body as described in [2]-[3].
[5] The laminate according to [4], wherein the crosslinkable modified polyamide is polyethylene glycol modified or N-methoxymethylated modified in a repeating structural unit, or carbodiimide modified.
[6] The laminate according to [1] to [5], wherein the thickness of the reinforcing layer is 0.005 mm to 1 mm.
[7] The reinforcing layer is a composition containing cellulose nanofibers and a dispersing agent, and containing a hydrophilic solvent, the crosslinkable resin and the crosslinking agent, or a composition comprising a hydrophilic solvent and the self-crosslinking resin, A method for producing a laminate, wherein the reinforcing layer is applied to one surface of the one surface of the single layer base layer or one or both sides of the two or more base layers and then adhered to each other, followed by crosslinking treatment.

  According to the present invention, it is a laminate having a base material layer A, at least two layers of a base material layer B, and a reinforcing layer, wherein the reinforcing layer is a synthetic resin containing cellulose nanofibers. Excellent, non-breakable laminates can be made in a relatively simple process.

The laminate of the present invention is unmodified in the reinforcing layer of the laminate comprising at least two layers of the plate-like or sheet-like base material layer A and the base material layer B (hereinafter sometimes referred to simply as the reinforcing layer). By using a composition comprising cellulose nanofibers and a water-soluble or water-dispersible crosslinkable resin, it is possible to obtain a laminate having high strength, rigidity, impact resistance, and resistance to cracking.
The base material layer A and the base material layer B may be made of the same material or different materials.

The crosslinkable resin composition comprising the cellulose nanofibers and the crosslinkable resin used in the reinforcing layer comprises unmodified cellulose nanofibers, water and a dispersant, a water-soluble or water-dispersible crosslinkable resin, and, if necessary, a crosslinkable resin. It is a crosslinkable resin composition in which a crosslinking agent for resin is dispersed in a hydrophilic solvent, and the composition is applied to one side (adhesion side) of the base layer A and the base layer B, laminated, adhered, By subjecting the crosslinkable resin composition to a crosslinking treatment, the strength and impact resistance become higher than those of the base material layer A and the base material layer B alone, and it is possible to make it difficult to be broken.
In the present invention, pulverization or reduction of the diameter of the unmodified cellulose nanofibers is carried out using, for example, a high-speed rotation type medialess disperser as described later. With such a reduction in diameter, unmodified cellulose nanofibers tend to be relatively rich in unmodified cellulose nanofibers with a fiber diameter of 3 to 20 nm.

[Laminate base layer]
An inspection window for visually checking and inspecting the inside of industrial machinery such as mixers and brabenders, and a plate shape that can be seen through the front window, rear window, and sunroof of transportation facilities such as automobiles, ships, and aircrafts. Structure includes glass, polycarbonate resin, acrylic resin, polystyrene resin, polyamide resin, polyvinyl chloride resin, polyethylene terephthalate resin, polyvinyl alcohol resin, ethylene / vinyl alcohol copolymer resin, polyethylene resin, polypropylene resin, polyetherimide resin, etc. Many, mostly transparent substrates are used.
Most of these substrates are made of a single material, but when the strength, rigidity and impact resistance are insufficient, the above-mentioned plate-like transparent substrates may be laminated. It is known that polyvinyl butyral resin is used as an adhesive layer of a plate-like substrate, for example, for windshields for vehicles, and plate-like, sheet-like, or film-like resins are also widely used in practice. Is used and has various functions.
As a substrate, in addition to the transparent resin as described above, it can be used as a laminate of a substrate layer comprising a metal such as iron or aluminum, and an inorganic material such as ceramic.

  In the present invention, when a resin in which the cellulose nanofibers described in detail below are compounded in the adhesive layer of the laminate as described above is used as a reinforcing layer, it is possible to use the material constituting the laminate more than The strength, rigidity and impact resistance become high and it becomes difficult to break. As a result, the thickness of the laminate can be reduced, and cracking due to stress can be prevented, so that safety during use can be enhanced and running costs can be reduced.

The laminate according to the present invention may be, for example, a flat panel display such as a liquid crystal display or an organic EL display, a solar cell, a lithium ion battery, a touch panel, an electronic paper, etc. Glass substrates, digital signage or light guide plates used therefor, cover glasses for lighting devices, or packaging materials for pharmaceuticals and food, etc., as long as it is a thick substrate of 1 to 5 mm or more, It can be used not only for the inspection window of the above-mentioned industrial equipment, or for the front window or rear window of a transportation facility such as a car, ship or aircraft, or a sunroof, etc. It is not limited.
As a base material, it is desirable that it is transparent if it is a window material for transmission observation.

[Adhesive reinforcement layer]
The reinforcing layer of the laminate of the present invention has adhesiveness to a substrate, and comprises unmodified cellulose nanofibers and a dispersing agent, a water-soluble or water-dispersible crosslinkable resin, and, if necessary, a crosslinkable resin. It is a composition containing a crosslinking agent. Since the unmodified cellulose nanofibers are substantially uniformly dispersed in the crosslinkable resin by the action of the dispersing agent as described later, the reinforcing layer having the adhesiveness of the laminate of the present invention has a mechanical strength. Since the rigidity is high, not only the cracking of the laminate can be prevented but also the laminate can be made excellent in weather resistance, heat resistance, chemical resistance, transparency and the like. In addition, when the crosslinkable resin further contains a crosslinking agent, or when the self-crosslinkable resin is contained as the crosslinkable resin, cross-linking resin (or self-crosslinkable resin) between non-modified cellulose nanofibers by the crosslinking treatment described later. In the meantime, since the crosslinked structure is introduced to any one of the unmodified cellulose nanofibers and the crosslinkable resin (or the self-crosslinkable resin), the above-mentioned respective properties can be further improved.

The adhesive reinforcing layer of the laminate of the present invention contains unmodified cellulose nanofibers, a water-soluble or water-dispersible crosslinkable resin, a water-soluble dispersant, and a hydrophilic solvent, and the content of unmodified cellulose nanofibers is The unmodified cellulose nanofibers are non-modified cellulose nanofibers having a fiber diameter of 3 to 20 nm, which is 0.1 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the crosslinkable resin.
The details of each component are as follows.

[Cellulose nanofibers]
Unmodified cellulose nanofibers are cellulose nanofibers (hereinafter referred to as unmodified cellulose nanofibers) in which the hydroxyl group derived from cellulose in the molecular chain and / or at the molecular chain terminal is not hydrophobically modified. In the present invention, non-modified cellulose nanofibers are fibrous substances obtained by loosening cellulose raw materials such as plant-derived pulp by mechanical disintegration or oxidation treatment with an oxidation catalyst described later. In the cellulose raw material, for example, a plurality of hydroxyl groups on the surface form hydrogen bonds in one cellulose nanofiber, and a hydroxyl group on one cellulose nanofiber surface and a hydroxyl group on another cellulose nanofiber surface are hydrogen By forming a bond, it may contain aggregates. The aggregate can be easily disintegrated by mechanical disintegration treatment or the like.

  The non-modified cellulose nanofibers used in the present invention include non-modified cellulose nanofibers having a fiber diameter in the range of 3 to 20 nm by mechanical fibrillation treatment or chemical oxidation treatment. It is an experiment that unmodified cellulose nanofibers having a fiber diameter in the above range have a higher reinforcing effect on mechanical properties by being uniformly dispersed in a resin, as compared to fiber diameters in a range other than the above range. It has been confirmed.

  The fiber diameter and the fiber length of the unmodified cellulose nanofiber are not particularly limited, but the fiber diameter is preferably 100 nm or less, more preferably 80 nm or less, still more preferably 60 nm or less, particularly preferably 3 to 40 nm, and the fiber length is preferably Is 10 to 1000 μm, more preferably 100 to 500 μm, and the aspect ratio (fiber length / fiber diameter) is 1000 to 15000, preferably about 2000 to 10000. The fiber diameter here is determined by measuring the fiber diameter of an arbitrary number (for example, 20) of non-modified cellulose nanofibers by electron microscope observation, and calculating the arithmetic mean value of the obtained measurement values.

  Unmodified cellulose nanofibers are very small at the nano-order as described above, so when dispersed in water at a low concentration, the fact that the unmodified cellulose nanofibers are dispersed in water is visually No, it becomes a transparent dispersion. In addition, when unmodified cellulose nanofibers are dispersed in water at high concentration, light scatters to form an opaque dispersion due to aggregates of relatively large size (larger than the wavelength of light). Here, the dispersion includes various forms such as an emulsion, a slurry, a gel, a paste and the like.

  As in the case of the adhesive reinforcing layer composition having adhesiveness according to the present invention, when non-modified cellulose nanofibers and a dispersant described later coexist in an aqueous system, at least a part of the non-modified cellulose nanofibers surface These functional groups and at least a part of the dispersing agent may combine to form these ionic conjugates. Such an ionic conjugate is considered to have a function of, for example, maintaining the dispersion stability of unmodified cellulose nanofibers at a high level over a long period of time.

  In the present invention, the unmodified cellulose nanofibers are preferably used in the form of an aqueous dispersion from the viewpoint of the dispersibility of the unmodified cellulose nanofibers in the obtained nanofiber composition. The content of unmodified cellulose nanofibers in the aqueous dispersion is not particularly limited, but is preferably 0.001 to 20% by weight of the total amount of the aqueous dispersion, and more preferably 0.1 to 10% by weight of the total amount of the aqueous dispersion It is.

The elastic modulus and strength of the unmodified cellulose nanofiber consisting of extended chain crystals reach 140 GPa and 3 GPa, respectively, and are equivalent to typical high-strength fibers and aramid fibers, and have higher elasticity than glass fibers. Furthermore, the linear thermal expansion coefficient is as small as 1.0 × 10 ⁻⁷ / ° C., which is comparable to that of quartz glass.

  The cellulose used for the production of unmodified cellulose nanofibers is preferably an aqueous dispersion. The shape of the cellulose is, for example, any shape such as fibrous and granular, and as the cellulose, microfibrillated cellulose from which lignin and hemicellulose are removed is preferable. Alternatively, commercially available cellulose may be used. When the microfibrillated cellulose is treated with a medialess disperser, the microfibrillated cellulose unfolds and thins hydrogen bonds derived from hydroxyl groups present on the fiber surface while maintaining the length of the fiber, but the treatment conditions are changed. It is also possible to cut the fibers or reduce the molecular weight.

  The amount of unmodified cellulose nanofibers (hereinafter, cellulose nanofibers may be referred to as CNF) in the adhesive reinforcing layer composition having adhesiveness of the present invention is not particularly limited, but the reinforcing layer of the laminate of the present invention In consideration of the balance of coating properties, strength, rigidity and impact resistance, etc., it is preferably in the range of 0.1 parts by weight to 20 parts by weight with respect to 100 parts by weight of the crosslinkable resin, more preferably 0. It is in the range of 5 parts by weight to 5.5 parts by weight. If the blending amount of unmodified cellulose nanofibers is less than 0.5 parts by weight, the strength, rigidity and impact resistance of the laminate of the present invention as a reinforcing layer tend to be insufficient. On the other hand, when the blending amount of the unmodified cellulose nanofibers is 10 parts by weight or more, the adhesive reinforcing layer composition of the laminate of the present invention is greatly thickened, and the coating property, the handleability and the like tend to be remarkably reduced. There is. As a result, it tends to be difficult to form the uniformity of the film thickness as the reinforcing layer of the laminate of the present invention.

[Crosslinkable resin]
The crosslinkable resin of the present invention is one having water solubility or water dispersibility. The water-soluble crosslinkable resin is a crosslinkable resin that can be dissolved in a hydrophilic solvent. A water dispersible crosslinkable resin refers to a forced emulsification type crosslinkable resin that can be dispersed in a hydrophilic solvent by an emulsifier or the like, and a hydrophilic group introduced into the side chain and / or the end of the main chain skeleton thereof. And a self-emulsifying type crosslinkable resin that can be dispersed in a hydrophilic solvent.

  The crosslinkable resin used in the present invention is a crosslinkable resin having at least one selected from a crosslinkable group and a crosslinkable structure, for example, a crosslinkable resin which reacts with a crosslinker to form a crosslink structure, preferably It is a crosslinkable resin which is at least one member selected from an acid group and a crosslinkable structure and has water solubility or water dispersibility. Here, the crosslinkable group is not particularly limited, and examples thereof include an epoxy group, a hydroxy group, an isocyanate group, an amino group, an amido group, a carboxyl group, an ether group (for example, fluoroethylene ether group etc.) and a hydrosilyl group. The crosslinkable resin can have one or more crosslinkable groups. These crosslinkable groups may be bonded to the main chain skeleton of the crosslinkable resin as at least a part of side chains, or may be bonded to the end of the main chain skeleton.

  The crosslinkable structure is not particularly limited, and examples thereof include a pyrrolidone structure, a siloxane structure, and an oxetane structure. The crosslinkable resin can have one or more crosslinkable structures. These crosslinkable structures may form part of the main chain skeleton of the crosslinkable resin, and may be bonded to the side chain and / or the end of the main chain skeleton of the crosslinkable resin.

  In addition, the crosslinkable resin may have a hydrophilic group in order to exhibit water solubility or water dispersibility. The hydrophilic group is not particularly limited, and examples thereof include a hydroxy group, an amino group, a carboxyl group, a sulfone group, an ether group and the like. The hydrophilic group may be bonded to the main chain skeleton of the crosslinkable resin as a part of a side chain, or may be bonded to the end of the main chain skeleton. Among these hydrophilic groups, a crosslinkable resin having a hydroxy group, an amino group, a carboxyl group, an ether group or the like is a crosslinkable resin having water dispersibility or water solubility.

  Among the above-mentioned crosslinkable resins, as a crosslinkable resin having predetermined mechanical strength and high adhesiveness, a group consisting of vinyl alcohol, vinyl acetate, vinyl butyral, acrylic acid, methacrylic acid and ethylene A copolymer of at least one ethylenic double bond-containing compound selected from the above, derivatives thereof, modified polyamide resin soluble in water or alcohol, and cross-linked copolymerized polyamide Polyvinyl alcohol resin, ethylene vinyl alcohol copolymer resin, polyvinyl butyral resin, modified polyamide resin and the like are more preferable from the viewpoint of dispersibility of the unmodified cellulose nanofibers in the crosslinkable resin and the like. The polyvinyl alcohol resin and the polyvinyl butyral resin are not only excellent in film forming property, transparency, flexibility, etc., but also easily penetrate into the gaps between the unmodified cellulose nanofibers, and the fine unevenness of the base material adhesion interface to be adhered It is possible to produce a reinforcing layer that conforms well to the shape, has high strength, rigidity and impact resistance as a laminate, and also has high adhesion.

  In addition, as the water- or alcohol-soluble modified polyamide resin and the crosslinkable copolyamide used in the present invention, all conventionally proposed ones are included. For example, as described in JP-A-48-72250, a polyamide containing a sulfonic acid group or a sulfonate group obtained by copolymerizing sodium 3,5-dicarboxybenzene sulfonate etc. It has an ether bond which is obtained by copolymerizing any one kind of dicarboxylic acid having an ether bond, a diamine or a cyclic amide as shown in the publication 49-43465. Polyamides, Basic nitrogen-containing polyamides obtainable by copolymerizing N, N'-di (.gamma.-aminopropyl) piperazine, etc. as disclosed in JP-A 50-7605, and polyamides thereof Polyamides quaternized with acrylic acid or the like, polyesters having a molecular weight of 150 to 1,500 proposed in JP-A-55-74537. Ring-opening polymerization of .alpha .- (N, N'-dialkylamino)-. Epsilon.-caprolactam and .alpha .- (N, N'-dialkylamino)-. Epsilon.-caprolactam and .epsilon.-caprolactam Examples thereof include polyamides obtained by ring-opening copolymerization.

Among these water-soluble polyamides, copolymerized polyamides containing polyether segments having a molecular weight of 150 to 1,500, more specifically, having an amino group at the terminal end, the molecular weight of the polyether segment portion is 150 to 1 Copolyamides containing 30 to 70% by weight of a constitutional unit consisting of polyoxyethylene and an aliphatic dicarboxylic acid or diamine of 500, 500 are preferably used.
These water-soluble polyamides may be used alone or in combination of two or more.

On the other hand, alcohol-soluble polyamides used in the present invention include linear polyamides synthesized by known methods from dibasic fatty acids and diamines, ω-amino acids, lactams or derivatives thereof, and homopolymers alone Copolymers, block polymers, etc. can also be used. A polyamide having a substituent on the carbon atom or nitrogen atom constituting the main chain can also be used, or a polyamide containing a bond other than C-C and -C-N-CO- bond in the main chain may be used. The following is a representative example. Nylons 3, 4, 5, 6, 8, 11, 12, 13, 13, 66, 610, 6/10, 13/13, Polyamides from metaxylylenediamine and adipic acid, trimethylhexamethylenediamine, or isophoronediamine and adipine Polyamide from acid, ε-caprolactam / adipic acid / hexamethylene diamine / 4,4'-diaminodicyclohexylmethane copolymerized polyamide, ε-caprolactam / adipic acid / hexamethylene diamine / 2,4,4'-trimethylhexamethylene diamine Copolymerized polyamides, ε-caprolactam / adipate / hexamethylene diamine / isophorone diamine copolymerized polyamides, or polyamides containing these components, N-methylol and N-alkoxymethyl derivatives thereof can also be used.
These alcohol-soluble polyamide resins may be used alone or in combination of two or more.

  As specific examples of the water-soluble or alcohol-soluble (B) modified polyamide resin as described above, AQ nylon manufactured by Toray Industries, Inc., fine resin manufactured by Lead City, Inc., Nagase ChemteX Corporation manufactured Toresin and the like.

  Here, although the molecular weight of the crosslinkable resin is not particularly limited, for example, in order to improve the strength, rigidity and impact resistance of the laminate having the reinforcing layer finally obtained, the weight average molecular weight is It is preferable that it is 2,000 or more.

  In the present invention, when using a water-soluble or water-dispersible crosslinkable resin, it is preferable to use a crosslinking agent capable of reacting with the crosslinkable group and / or the crosslinkable structure of the crosslinkable resin in combination with the crosslinkable resin. . The crosslinking agent will be described later.

  Here, the self-crosslinkable resin is a synthetic resin which can form a crosslinked structure in its own molecule without using a crosslinking agent. The self-crosslinking resin is not particularly limited as long as it is water-soluble or water-dispersible, and, for example, polyvinyl toluene, t-butyl acrylate / glycidyl acrylate copolymer, carboxyl group-containing vinyl monomer / sulfonic acid A group containing vinyl monomer copolymer etc. are mentioned. Moreover, the crosslinking agent mentioned later with self-crosslinkable resin can also be used. In addition, as self-crosslinkable resin, what is water-soluble or water-dispersible is preferable.

  In the present invention, the crosslinkable resin is preferably used in the form of a solution or an aqueous dispersion. When the crosslinkable resin is water soluble, the solution of the crosslinkable resin is preferably a solution in which the crosslinkable resin is dissolved in a hydrophilic solvent. Examples of the hydrophilic solvent include water, an organic solvent soluble in water, and a mixed solvent of water and an organic solvent soluble in water. When the crosslinkable resin is water dispersible, the dispersion liquid of the crosslinkable resin is an emulsion such as a forced emulsification type emulsion or a self emulsification type emulsion, a slurry, etc., using the same hydrophilic solvent as that described above as a dispersion medium. Is preferred. A forced emulsification type emulsion is one in which a crosslinkable resin is dispersed in a hydrophilic solvent using a surfactant or another emulsifier. The self-emulsifiable emulsion is a crosslinkable resin dispersed in a hydrophilic solvent by introducing a hydrophilic group as a side chain and / or an end group into the main chain skeleton of the crosslinkable resin.

[Hydrophilic solvent]
Examples of hydrophilic solvents in the present invention include monohydric or polyhydric alcohols (eg, monohydric alcohols include lower alcohols having 1 to 4 carbon atoms), amides, ketones, keto alcohols, cyclic ethers , Glycols, lower alkyl ethers of polyhydric alcohols, polyalkylene glycols, glycerin, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, glycerin, ethylene glycol, Diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,6 2,6-Hexane tri Polyols such as trimethylolpropane and pentaerythritol, Polyhydric alcohol alkyl ethers such as diethylene glycol monobutyl ether and tetraethylene glycol monomethyl ether, Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether And polyhydric alcohol aralkyl ethers, lactams such as 2-pyrrolidone, N-methyl-2-pyrrolidone, ε-caprolactam, 1,3-dimethylimidazolidinone acetone, N-methyl-2-pyrrolidone, m-butyrolactone, Polyoxyalkylene adduct of glycerin, propylene glycol monomethyl ether acetate, dimethyl sulfoxide, diacetone alcohol, dimethylformamide And propylene glycol monomethyl ether. The water-soluble solvents can be used alone or in combination of two or more.

As water, pure water such as ion exchange water, ultrafiltered water, reverse osmosis water, distilled water or ultrapure water can be used. In addition, it is preferable to use water sterilized by ultraviolet irradiation, hydrogen peroxide addition or the like, since the generation of mold or bacteria in long-term storage can be prevented.
Water is particularly preferable because it does not require special waste liquid treatment equipment and is less likely to cause environmental pollution.

  When the crosslinkable resin is a solution or an aqueous dispersion, the concentration of the crosslinkable resin is not particularly limited, but the uniform dispersion of nanofibers and crosslinkable resin in the obtained nanofiber composition, an aqueous solution of the crosslinkable resin Or from the viewpoint of the handleability of the aqueous dispersion, preferably 1 to 50% by weight, more preferably 5 to 45% by weight, still more preferably 10 to 40% by weight of the total amount of the solution or dispersion of the crosslinkable resin .

Dispersant
The dispersant is a water-soluble dispersant, preferably a water-soluble dispersant capable of ionically binding to functional groups such as hydroxyl groups possessed by unmodified cellulose nanofibers on its surface, more preferably unmodified cellulose nanofibers possess on its surface A dispersant which is capable of ionically binding to functional groups such as hydroxyl groups and which can enhance the dispersibility and dispersion stability of unmodified cellulose nanofibers in the adhesive reinforcing layer composition of the present invention by electrostatic repulsion etc. is there. The dispersant is not particularly limited as long as it is water-soluble as described above, but anionic dispersants can be preferably used. As the anionic dispersant, for example, a compound having at least one kind of functional group selected from phosphoric acid group, -COOH group, -SO ₃ H group, metal ester group thereof, and imidazoline group, acryloyloxyethyl A phosphoryl choline (co) polymer etc. are mentioned. An anionic dispersant can be used individually by 1 type or in combination of 2 or more types.

  Specific examples of the anionic dispersant are not particularly limited. For example, polyacrylic acid and its salt, polymethacrylic acid and its salt, polyacrylic acid copolymer and its salt, polyitaconic acid and its salt, olefin-derived monomer And copolymers containing monomers derived from unsaturated carboxylic acids (salts) (for example, JP-A-2015-196790), polymaleic acid copolymers and salts thereof, polystyrene sulfonic acids and salts thereof, sulfonic acid group-bound polyesters, etc. Carboxylic acid type anionic dispersants, heterocyclic ring type anionic dispersants such as alkyl imidazoline type compounds (eg, JP-A-2015-934, JP-A-2014-118521 etc.), acid value and amine value Anionic dispersants (eg, Tokkai 2010-186124 etc.), pyrophosphoric acid, polyphosphoric acid, Phosphoric anionic dispersants such as polyphosphoric acid, tetrapolyphosphoric acid, metaphosphoric acid, trimetaphosphoric acid, tetrametaphosphoric acid, hexametaphosphoric acid, phosphonic acid and salts thereof, sulfonic acids, dodecyl benzene sulfonic acid, lignin sulfonic acid, etc. Examples thereof include sulfonic acid-based anionic dispersants such as salts, ortho-silicic acid, meta-silicic acid, humic acid, tannic acid, dodecyl sulfuric acid, and other anionic dispersants such as salts thereof. Among these, phosphoric acid, polyphosphoric acid, phosphate, polyphosphate, polyacrylic acid, polyacrylic acid copolymer, polyacrylic acid salt, polyacrylic acid copolymer salt and the like are preferable.

  In addition, as the anionic dispersant, a copolymer obtained by copolymerizing acrylic acid or methacrylic acid and another monomer can also be used. As other monomers, for example, unsaturated carboxylic acids such as α-hydroxy acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid and their salts, 2-acrylamido-2-methylpropane sulfonic acid, Examples thereof include unsaturated sulfonic acids such as meta) allyl sulfonic acid and styrene sulfonic acid, and salts thereof.

  The cation constituting the salt of the above-mentioned anionic dispersant is not particularly limited, and examples thereof include alkali metals such as sodium, potassium and lithium, alkaline earth metals such as calcium, magnesium and ammonium groups. From the viewpoint of solubility in water, sodium, potassium, ammonium groups and the like are more preferable, and potassium is most preferable.

  In the present invention, a commercially available anionic dispersant may be used, and as a specific example of the commercially available product, Aron A-6114 (trade name, carboxylic acid-based dispersant, manufactured by Toagosei Co., Ltd.), Aron A-6012 (Trade name, sulfonic acid dispersant, manufactured by Toagosei Co., Ltd.), demol NL (trade name, sulfonic acid dispersant, manufactured by Kao Corp.), SD-10 (trade name, polyacrylic acid dispersant) And Toa Gosei Co., Ltd.).

  Further, as the anionic dispersant used in the present invention, a (meth) acryloyloxyethyl phosphoryl choline (co) polymer may be used. The (meth) acryloyloxyethyl phosphorylcholine (co) polymer can increase the dispersion stability of each component in the nanofiber composite obtained by the present invention, in particular the dispersion stability of the nanofiber, and, for example, And the nanocellulose composite of the present invention can be suitably used as a dispersant when used for medical applications, food applications and the like. Here, (meth) acryloyloxyethyl phosphoryl choline includes methacryloyl oxyethyl phosphoryl choline and acryloyl oxyethyl phosphoryl choline. These are manufactured according to a conventional method. For example, 2-bromoethyl phosphoryl dichloride, 2-hydroxyethyl phosphoryl dichloride and 2-hydroxyethyl methacrylate are reacted to obtain 2-methacryloyloxyethyl-2'-bromoethyl phosphoric acid, which is further dissolved in trimethylamine and methanol solution. Can be obtained by reaction.

  In the present invention, a commercially available product of (meth) acryloyloxyethyl phosphorylcholine (co) polymer may be used, and specific examples of the commercially available product include, for example, lipidum HM, lipidum BL (all are trade names, polymethacryloyloxyethyl phosphorylcholine And lipidoir PMB (trade name: methacryloyloxyethyl phosphorylcholine / butyl methacrylate copolymer), lipidaia NR (trade name: methacryloyloxyethyl phosphorylcholine / stearyl methacrylate copolymer), and the like. All of these are manufactured by NOF Corporation.

[Crosslinking agent]
The crosslinking agent in the present invention mainly causes a crosslinking reaction with a crosslinkable group that the crosslinkable resin has, a crosslinked structure, and a functional group that the cellulose nanofibers have on the surface. As a result of the crosslinking reaction, a crosslinked structure derived from the crosslinking agent is formed in at least one of the crosslinkable resins, the unmodified cellulose nanofibers, and the crosslinkable resin and the unmodified cellulose nanofibers. The mechanical strength such as strength, rigidity and impact resistance of the laminate having the base material layer A, the base material layer B and the reinforcing layer can be enhanced.

  The crosslinking agent is not particularly limited as long as it has a crosslinking property or crosslinking structure of the crosslinkable resin, or a reactivity with a functional group or the like of the unmodified CNF on the surface. Resins, organic peroxides, polymerization initiators and the like. These crosslinking agents can be used singly or in combination of two or more.

  As polyfunctional monomers, polyfunctional acrylic monomers, polyfunctional allyl monomers, mixed monomers thereof and the like can be mentioned.

  Specific examples of the polyfunctional acrylic monomer include, for example, ethylene oxide modified bisphenol A di (meth) acrylate, 1,4-butanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, dipentaerythritol hexaacrylate, and dipenta Erythritol monohydroxy pentaacrylate, caprolactone modified dipentaerythritol hexaacrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane triacrylate, EO modified trimethylol propane tri (Meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, tris (acrylo) Shiechiru) isocyanurate, tris (methacryloxyethyl) isocyanurate and the like. Among these, tris (acryloxyethyl) isocyanurate (triacrylic acid ester of tris (2-hydroxyethyl) isocyanuric acid) can be preferably used from the viewpoint of low skin irritation. A polyfunctional acrylic monomer can be used individually by 1 type or in combination of 2 or more types.

  Examples of polyfunctional allyl-based monomers include triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), diallyl monoglycidyl isocyanurate (DA-MGIC), diallyl phthalate, diallyl benzene phosphonate and the like. The polyfunctional allyl-based monomers can be used singly or in combination of two or more.

  The polyfunctional monomer can be used in combination with a polymerization initiator, if necessary, and an acid catalyst, a stabilizer and the like can be used in combination. The timing of addition of the polymerization initiator, catalyst, stabilizer and the like to the adhesive reinforcing layer composition of the present invention is not particularly limited, and for example, unmodified CNF, crosslinkable resin, dispersant, and hydrophilic solvent are mixed simultaneously.

  Although the compounding quantity of a polyfunctional monomer is not specifically limited, Preferably it is 0.01-10 weight% with respect to solid content weight of crosslinkable resin, More preferably, it is 0.1-5 weight%. When the blending amount of the polyfunctional monomer is less than 0.01% by weight, mechanical properties and thermal properties of the adhesive reinforcing layer composition of the present invention tend not to be significantly improved. If the content of the polyfunctional monomer exceeds 10% by weight, mechanical properties such as strength, rigidity and impact resistance of the laminate having the reinforcing layer of the present invention tend to be adversely affected.

  Specific examples of the polyfunctional resin (polyfunctional polymer) include, for example, epoxy resin, isocyanate resin, cyanate resin, maleimide resin, acrylate resin, methacrylate resin, unsaturated polyester resin, oxetane resin, vinyl ether resin, urea resin, Melamine resin etc. are mentioned. Among these, radiation curable resins such as thermosetting epoxy resin and epoxy (meth) acrylate resin are preferable. The polyfunctional resin has a molecular weight relatively lower than that of the crosslinkable resin. The molecular weight of the polyfunctional resin is preferably less than 1000 as weight average molecular weight. The polyfunctional resin is preferably a self-emulsifying resin modified with a hydrophilic group such as a hydroxyl group or a carboxyl group as in the crosslinkable resin, or a forced emulsifying resin capable of being dispersed in a dispersion medium by an emulsifying agent. When these resins are used as a crosslinking agent, it is preferable to use resins different in resin type from the crosslinkable resin. The compounding amount of the multifunctional resin is preferably 3 to 20% by weight, more preferably 5 to 15% by weight based on the solid content weight of the crosslinkable resin.

  The organic peroxide generates, for example, free radicals upon heating, whereby at least a portion of crosslinkable resins, non-modified cellulose nanofibers, cross-linkable resin and non-modified cellulose nanofibers is formed. Crosslink. Although organic peroxides fall under the category of polymerization initiators, they are described separately from the polymerization initiators in this specification. Specific examples of the organic peroxide include, for example, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5- Dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5 -Trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert -Butyl peroxy isopropyl carbonate, diacetyl peroxy Id, lauroyl peroxide, tert- butyl cumyl peroxide, benzoyl peroxide, etc. tert- butyl hydroperoxide and the like. The organic peroxides can be used singly or in combination of two or more. The blending amount of the organic peroxide is preferably 0.0001 to 10% by weight, more preferably 0.01 to 5% by weight, further preferably 0 based on the total solid content of the crosslinkable resin and the unmodified cellulose nanofibers. 1 to 3% by weight.

  The polymerization initiator generates free radicals, for example, by heating or ionizing radiation irradiation, whereby at least between crosslinkable resins, between unmodified cellulose nanofibers, between at least a crosslinkable resin and non-modified cellulose nanofibers. Cross-link part. As a specific example of a polymerization initiator, an azo compound, a persulfate, etc. are mentioned, for example. The polymerization initiator may be water soluble or hydrophobic.

  Specific examples of the polymerization initiator include, for example, hydrophobic azo compounds such as azobisisobutyronitrile and 2,2′-azobis (2-methylbutyronitrile), and 2,2′-azobis [2- (2) -Imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2-methyl-N- (2-) Water-soluble azo compounds such as hydroxyethyl) propionamide]; and persulfates such as potassium persulfate, ammonium persulfate, sodium persulfate and the like. The blending amount of the polymerization initiator is preferably 0.0001 to 5% by weight, more preferably 0.01 to 3% by weight, still more preferably 0.1 to 5% by weight based on the total solid content of the crosslinkable resin and the nanofibers. It is about 1% by weight.

  In the present invention, an acid catalyst may be used together with the crosslinking agent. The acid catalyst is used, for example, to promote the reaction of the crosslinkable group of the crosslinkable resin and / or the crosslink structure with the nucleophilic reactive group of the crosslinker. Specific examples of the acid catalyst include, for example, organic acids such as p-toluenesulfonic acid, citric acid, acetic acid and malic acid, inorganic acids such as hydrochloric acid, sulfuric acid and sulfonic acid, boron trifluoride, zinc chloride, tin chloride, Lewis acids such as aluminum chloride can be mentioned. An acid catalyst can be used individually by 1 type or in combination of 2 or more types. The blending amount of the acid catalyst is preferably 0.1 to 8 parts by weight with respect to 100 parts by weight of the solid content of the crosslinkable resin. If the compounding amount of the acid catalyst is less than 0.1 parts by weight, the degree of crosslinking may be too low, and if it exceeds 8 parts by weight, the compatibility in the nanofiber composite may be deteriorated.

  In addition, the dispersibility and dispersion stability of the unmodified cellulose nanofibers can be further improved by blending an alkaline agent in the aqueous solution of the adhesive reinforcing layer composition of the present invention and adjusting the pH to a weak alkali. . The alkali agent is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate and the like. The alkali agents can be used alone or in combination of two or more.

[Other additives]
Further, in the present invention, hindered phenols, antioxidants such as phosphoric acid esters and phosphorous acid esters, heat resistant stabilizers, triazines, and the like within the range not impairing the preferable characteristics of the adhesive adhesiveness-reinforcing layer composition having adhesiveness. Compounds such as weathering agents, stabilizers, plasticizers, antistatic agents, flame retardants, preservatives, pigments, colorants such as dyes, lubricants, water repellants, anti blocking agents, flexibility improvers, leveling agents Antifoaming agents, metal soaps, organic silanes, organic metal compounds, preservatives, etc. can be blended. These additives may be mixed in a single step simultaneously with the above-described components, or may be added to and mixed with the aqueous solution of the adhesive reinforcing layer composition having adhesiveness obtained.

  The method for producing a laminate having the reinforcing layer of the present invention includes, for example, a mixing step of an adhesive reinforcing layer composition, and a pre-mixing step performed before the mixing step, a coating step performed after the mixing step Includes engineering process and crosslinking process. According to this manufacturing method, an adhesive reinforcing layer composition in which unmodified cellulose nanofibers are substantially uniformly dispersed in a crosslinkable resin, adhesion of at least one of the base material A and the base material B to the adhesive reinforcing layer composition A laminate obtained by coating on the surface and adhering the both, and a laminate obtained by crosslinking at least a part of the solid content of the adhesive reinforcing layer composition are obtained. The details of each step are as follows.

[Pre-mixing step]
In the pre-mixing step, the hydrophilic solvent is selected from the group consisting of unmodified cellulose nanofibers, water-soluble or water-dispersible crosslinkable resins, water-soluble dispersants, if necessary, crosslinking agents, and other additives. Add and mix at least one of When unmodified cellulose nanofibers, crosslinkable resins, water-soluble dispersants, etc. are added to the hydrophilic solvent, the pre-mixture (b) is obtained by merely mixing without mechanical disintegration treatment. Be When unmodified cellulose nanofibers and dispersant are added to and mixed with a hydrophilic solvent to obtain a pre-mixture (b), mixing may be performed under mechanical disintegration treatment, or only simple mixing may be performed. It is also good. For the mixing here, for example, a mixing apparatus such as a homogenizer, a rocking mill, a Henschel mixer, an in-line mixer, a twin-screw kneader or the like is used, and it is preferable to use a crosslinking agent together with the crosslinkable resin.

[Mixing process]
In the mixing step, nanofibers, a water-soluble or water-dispersible crosslinkable resin, a water-soluble dispersant, a hydrophilic solvent, a crosslinking agent as needed, and other additives are subjected to mechanical disintegration treatment in one step. Mix with. In the mixing step, the pre-mixture (a) obtained in the pre-mixing step may be subjected to mechanical disintegration treatment, and a crosslinkable resin, a hydrophilic solvent and the like are further added and mixed to the pre-blend (b). While performing two-stage mixing, mechanical disintegration processing may be performed. Here, mixing in a single stage means that the above-described components are introduced into the same container at one time and mixed. In the mixing step, the crosslinkable resin is not in the hydrophilic solvent solution or the hydrophilic solvent dispersion (hereinafter referred to as “the aqueous dispersion of the adhesive reinforcing layer composition”) of the adhesive reinforcing layer composition to be obtained. From the viewpoint of dispersibility of the modified cellulose nanofibers, it is preferably used in the form of a solution or dispersion, and more preferably in the form of a hydrophilic solvent solution or a hydrophilic solvent dispersion. Also, nanofibers, dispersants, crosslinking agents and other additives may be used separately in the form of being dissolved or dispersed in a hydrophilic solvent.

  The mechanical fibrillation treatment is carried out using an apparatus capable of applying a shearing force to the mixture obtained by injecting each component into the same container substantially simultaneously in the pre-mixing or mixing step obtained in the pre-mixing step. As such an apparatus, a high-pressure homogenizer, counter collision in water, a high-speed rotary disperser, a beadless disperser, a high-speed stirring type medialess disperser, etc. may be mentioned. Among these, not only the dispersibility of the unmodified cellulose nanofibers in the crosslinkable resin is further improved, but also the mixing of impurities is small, and from the viewpoint of obtaining a high purity nanofiber composite, high-speed stirring type Medialess dispersers are preferred.

  The high-speed stirring type medialess disperser is a disperser that performs dispersion processing using the shear force of a rotating body without using dispersion media (for example, beads, sand (sand), balls, etc.). A medialess dispersing machine can use a commercial item. Examples of the commercially available product include DR-PILOT 2000, ULTRA-TURRAX series, Dispax-Reactor series (all trade names, manufactured by IKA), T.I. K. Homomixer, T.I. K. Pipeline homomixer (all trade names, manufactured by Primix (trade name), High Shear Mixer (trade name, manufactured by Silverson), milder, cavitron (all trade names, manufactured by Taiyo Kiko Co., Ltd.), Creamix (trade name, manufactured by M Technique Co., Ltd.), homomixer, pipeline mixer (trade name, manufactured by Mizuho Kogyo Co., Ltd.), jet paster (trade name, manufactured by Nippon Spindle Manufacturing Co., Ltd.), Apex Disper ZERO (trade name, manufactured by Hiroshima Metal & Machinery Co., Ltd.) and the like.

  Among the high speed stirring type medialess dispersing machines, a high speed stirring type medialess dispersing machine of a type provided with a stator and a rotor is preferable. Specific examples of this type include, for example, a type including a stator and a rotor rotating inside the stator, and a type in which the stator and the rotor are installed in multiple stages. Among the above-mentioned commercial products, Apex Disperser ZERO is this type. In this type, there is a gap between the stator and the rotor. The size of this gap is "shear portion clearance". By passing the mixed solution of the above components through the gap between the stator and the rotor under rotation of the rotor, it is possible to apply a shearing force to the mixed solution, so that unmodified cellulose It is possible to further reduce the diameter of nanofibers and further improve uniform dispersion of unmodified cellulose nanofibers in a crosslinkable resin. Further, from the viewpoint of applying shear force uniformly to the entire mixture of the above components, it is preferable to use an inline circulation type high-speed stirring type medialess disperser in which the mixture of the above components circulates in the apparatus.

  In the case of using a high-speed stirring type medialess disperser, it is possible to obtain unmodified cellulose nanofibers by setting the shear rate, the shear portion clearance and the circumferential speed of rotation of the rotor, particularly the shear portion clearance and the circumferential speed of rotation of the rotor within a predetermined range. The inventors of the present invention have been able to obtain superior effects such as further reduction in diameter, further uniform dispersion in a crosslinkable resin, and prevention of sedimentation of unmodified cellulose nanofibers in the resulting composite for an adhesive interlayer. It turns out by research.

  The shear rate is preferably more than 900,000 [1 / sec]. When the shear rate is 900,000 [1 / sec] or less, there is a tendency that the further defibrillation of the unmodified cellulose nanofibers and the dispersion in the crosslinkable resin are both insufficient. The shear rate is preferably 2,000,000 [1 / sec] or less, preferably 1,500,000 [1 / sec] or less, and more preferably 1,200,000 [1 / sec] or less.

  The shear area clearance is appropriately set according to the shear rate, the viscosity of the mixture of the above components, etc., but the diameter of the unmodified cellulose nanofibers is reduced as much as possible, and the crosslinkable resin of the unmodified cellulose nanofibers From the viewpoint of achieving further improvement of the dispersibility in the toner, it is preferably 100 μm or more, more preferably 150 μm or more, and still more preferably 200 μm or more. Furthermore, from the viewpoint of securing high dispersibility while maintaining the number of rotations of the dispersing machine within an appropriate range even if the viscosity of the mixture of the above components is high, the clearance is preferably 2 mm or less, more preferably 1.5 mm or less And 1.2 mm or less is more preferable.

  The rotational peripheral speed of the rotor is appropriately set according to the shear rate, but from the viewpoint of further improving the maximum diameter reduction diameter of the unmodified cellulose nanofibers and the dispersibility in the crosslinkable resin. 18 m / s or more is preferable, 20 m / s or more is more preferable, and 23 m / s or more is more preferable. Also the strength of the middle layer. 60 m / s or less is preferable, 50 m / s or less is more preferable, and 45 m / s or less is more preferable, in order to obtain an optimal fiber diameter of 10 to 20 nm from the viewpoint of rigidity and impact resistance. The rotational peripheral speed is the peripheral speed at the leading end of the rotor.

  Although the compounding quantity of each component mentioned above is not specifically limited in a pre-mixing process and a mixing process, For example, the unmodified | non_denatured cellulose nanofiber is preferably 0. 1 part by weight to 20 parts by weight, more preferably 0.5 to 5.5 parts by weight, preferably 100 to 10,000 parts by weight of a hydrophilic solvent, more preferably 150 to 1000 parts by weight, preferably 0.01 for a dispersant It may be blended at about 0.5 parts by weight, more preferably 0.025 to 0.25 parts by weight. The compounding amount of the crosslinking agent is as described above.

  The solution or dispersion of the adhesive reinforcing layer composition obtained in the mixing step disperses the unmodified cellulose nanofibers and the crosslinkable resin almost uniformly in the hydrophilic solvent, and the unmodified nanofibers over time Sedimentation is very low. Further, in the solution or dispersion liquid of the adhesive reinforcing layer composition, a dispersant may be ionically bonded to the surface of at least a part of the unmodified cellulose nanofibers. The ionic conjugate of unmodified cellulose nanofibers and dispersant may remain even after coating and crosslinking described later. The average fiber diameter of the unmodified cellulose nanofibers contained in the solution or dispersion of the adhesive reinforcing layer composition is about 3 to 100 nm, preferably about 3 to 60 nm, and more preferably about 3 to 40 nm. It will contain 10 to 20 nm diameter unmodified cellulose nanofibers. That is, by performing the mixing step, the fiber diameter of the unmodified cellulose nanofibers may be further reduced.

  Further, the zeta potential of the solution or dispersion of the adhesive reinforcing layer composition obtained in the mixing step is preferably -20 to -50 mV, more preferably -30 to -45 mV. When the zeta potential is higher than −20 mV, nonuniform dispersion is likely to occur, and the unmodified cellulose nanofibers may be precipitated. On the other hand, when the zeta potential falls below -50 mV, unmodified cellulose nanofibers are cut, and there may be a case where a sufficient crosslinked network structure is not formed. In the present invention, the zeta potential of the solution or dispersion of the adhesive reinforcing layer composition after production may be measured, and the value of the zeta potential may be adjusted as necessary. The zeta potential of the aqueous solution or aqueous dispersion of the adhesive reinforcing layer composition of the present invention can be adjusted, for example, by the amount and type of the dispersing agent. The measuring method of the zeta battery will be described later.

[Coating process and adhesion process]
The adhesive reinforcing layer composition obtained by the above-mentioned steps can be applied and adhered to a substrate by a known method. Below, the process about the layered product which consists of two layers of base material layer A and base material layer B is described.
That is, after the bonding surfaces of the base material A and the base material B are previously washed and hydrophilized with oxygen plasma, the adhesive reinforcing layer is formed on the bonding surface of at least one base material (in this case, the base material A). Apply the composition. The coating method is not particularly limited. For example, known methods such as spin coater method, bar coater method, spray coating method, brush, spatula, brush or roller application, dipping method, solution casting method (casting method), etc. are applied. it can. The coating thickness can be arbitrarily set to 1 μm or more depending on the purpose. After that, the coated layer of the adhesive reinforcing layer composition is naturally dried at 80 ° C. for about 2 hours or naturally dried to adhere the coated surface of the base material A to the adhesive surface of the base material B. The temperature is maintained for 1 to 2 hours, and the adhesive reinforcing layer composition is melted to blend the adhesive surface of the backing of the base material A and the backing surface of the base material B. In this case, it is preferable that pressure be uniformly applied to the bonding surfaces of the base material A and the base material B by using a plurality of clamps or the like.

[Crosslinking step]
In the crosslinking step, the adhesive reinforcing layer composition of the present invention is subjected to a crosslinking treatment after the bonding step of the base material A and the base material B. At this time, in the case where the adhesive reinforcing layer composition contains a crosslinkable resin and a crosslinking agent, or in the case where the adhesive reinforcing layer composition is a self-crosslinking resin, at least one of the unmodified cellulose nanofibers is at least one. A crosslinker between one or more of the unmodified cellulose nanofibers and at least part of the crosslinkable resin (or self-crosslinkable resin), and between at least part of the crosslinkable resin (or self-crosslinkable resin) A crosslinked product of the adhesive reinforcing layer composition of the present invention containing a crosslinked product having a crosslinked structure formed by a self-crosslinkable resin is obtained. This improves the strength, rigidity and impact resistance of the laminate including the reinforcing layer of the present invention.

  The method of the crosslinking treatment is not particularly limited, but a chemical crosslinking method and a physical crosslinking method using a crosslinking agent or a self-crosslinking resin contained in the adhesive reinforcing layer composition of the present invention are preferable.

  Specific examples of the chemical crosslinking method include, for example, crosslinking by heating. The heating conditions include the component composition of the adhesive reinforcing layer composition, the solid concentration, the type and amount of the crosslinkable resin (or self-crosslinking resin) and the crosslinking agent, the degree of crosslinking to be set, and the adhesive reinforcing layer composition to be obtained Although it is appropriately selected according to the value of each physical property etc. which are set to the crosslinked body of a thing, a crosslinking is normally formed by the long-time heating under the temperature of about 30 degreeC or more. The heating condition is preferably 30 ° C. to 220 ° C. from the viewpoint of shortening the time required for crosslinking to save labor as the whole process and further improving each physical property of the adhesive reinforcing layer composition of the present invention after crosslinking. The temperature is preferably 1 minute or more, more preferably 1 to 40 minutes at a temperature of 100.degree. C. to 180.degree. C., and still more preferably 1 to 20 minutes (preferably 5 to 10 minutes) at 125.degree.

  Specific examples of physical crosslinking include, for example, crosslinking by irradiation of ionizing radiation. Crosslinking by irradiation with ionizing radiation has the advantage of being easy to control. The ionizing radiation is not particularly limited, and examples thereof include electron beam, γ-ray, X-ray, charged particle beam, ultraviolet ray, neutron beam and the like. Among these, ultraviolet rays, γ rays, electron beams and the like are preferable from the viewpoint of the availability of the device for generating ionizing radiation, the ease of control of the crosslinking reaction, the safety and the like.

On the other hand, in the case of crosslinking by ionizing radiation, the irradiation dose for obtaining the desired degree of crosslinking varies depending on the type and composition of the resin and is not particularly limited. However, when the irradiation dose is less than 10 kGy, molding is usually performed The degree of cross-linking of the body is insufficient, and desired heat resistance and rigidity at high temperature can not be obtained. On the other hand, there is a tendency for coloring to increase as the dose increases. Is apt to cause a problem that the rigidity etc. decreases. The preferred irradiation dose is 10 to 50 kGy.
In the case of using ultraviolet light as ionizing radiation, a preferable irradiation dose is about 1,000 (mJ / cm ² ).

  The degree of crosslinking is usually 20 to 98%, preferably 60 to 98%, as the degree of crosslinking. If the degree of crosslinking is less than 20%, it may not be possible to obtain an improvement in mechanical strength such as strength, rigidity and abrasion resistance of the laminate having the finally obtained reinforcing layer. When the degree of crosslinking exceeds 98%, the physical properties of the laminate may decrease due to the increase in molecular chain breakage and the like outside the region where the crosslinked structure is formed. The degree of crosslinking is determined, for example, as gel fraction (%). The specific method of determining the gel fraction (%) will be described later.

The laminate having the reinforcing layer of the present invention thus obtained can have higher strength, rigidity and impact resistance than the base layer alone, as described above, and can make the laminate structure thinner or repeat stress. Since the frequency of occurrence of cracks and the like due to the load can be reduced, the safety in use can be enhanced and the running cost can be reduced. The thickness of the reinforcing layer is not particularly limited, but can be arbitrarily set from the viewpoints of the adhesion strength between the base material layers, the rigidity of the laminate, the impact resistance and the like, and the coating workability. The laminate having the reinforcing layer of the present invention is used to visually check the inside of industrial machinery such as mixers and brabenders, check windows for inspection, front windows and rear windows of transportation facilities such as automobiles, ships and aircrafts, sunroofs, etc. It can be used for The base material layer constituting the laminate is not particularly limited as long as it can be bonded with a resin, but is preferably transparent from the viewpoint of the above-mentioned application and physical cross-linking treatment with ultraviolet light.
In addition, when glass or a material approved by FDA is used for the base material layer, it can be used for food and medicine manufacturing equipment, and the base material layer A and the equipment layer B should be a laminate having the above-mentioned reinforcing layer. Thus, the airtightness is enhanced, and the inside of the apparatus for installing the laminate can be used under reduced pressure or pressure.

  Hereinafter, the present invention will be specifically described by way of examples and comparative examples. In addition, the measuring method of each component used in the Example, an apparatus, a fiber diameter, zeta potential, gel fraction, impact resistance, and a bending characteristic is as follows.

<Base Layer A, Base Layer B>
A flat plate base layer of 1.0 × 25 × 75 mm was produced by injection molding using a polycarbonate resin (Iupilon S-2000, manufactured by Mitsubishi Engineering Plastics Co., Ltd., hereinafter abbreviated as PC).
For the glass plate base layer, a 1.0 × 25 × 75 mm soda lime glass plate was used as the base layer.
Further, in the evaluation in the comparative example of the present invention, a 2 × 25 × 75 mm PC base layer and a glass base layer were used, respectively.
<Cellulose nanofibers>
A non-modified cellulose nanofiber (trade name: BiNFi-s, manufactured by Sugino Machine Co., Ltd.) was used as a 5% by weight aqueous dispersion.
<Dispersing agent>
An acrylic sulfonic acid copolymer (trade name: Aron A-6012, manufactured by Toagosei Co., Ltd.) was used.
<Reinforcement layer resin>
Polyvinyl butyral resin (trade name: S-LEC KW-1, manufactured by Sekisui Chemical Co., Ltd., an aqueous solution with a solid content of 20% by weight) was used. (Hereafter referred to as "PVB")
A PEG-modified nylon resin (trade name: AQ nylon A-90, manufactured by Toray Industries, Inc.) was used as a methanol solution with a solid content of 20% by weight. (Hereafter referred to as "modified nylon")
<Crosslinking agent>
Both end isocyanate type polycarbodiimide (trade name: Carbodilite VS-02, multifunctional resin, manufactured by Nisshinbo Chemical Co., Ltd.) was used as a 40% by weight aqueous solution. (Hereafter, it is called "carbodiimide".)
Further, a polyfunctional allyl-based monomer (trade name: triallyl isocyanurate, TAIC, manufactured by Nippon Kasei Co., Ltd.) was used. (Hereafter referred to as "TAIC")
Furthermore, a multifunctional epoxy resin (trade name: TG-G, manufactured by Shikoku Kasei Kogyo Co., Ltd.) was used. (Hereafter referred to as "TG-G")
<Crosslinking treatment>
As physical cross-linking, 30 kGy of γ-rays was irradiated to the laminate obtained by coating and laminating the adhesive reinforcing layer composition. Moreover, the adhesive reinforcement layer composition was coated as chemical crosslinking, and the laminated body which laminated | stacked was heat-processed at 170 degreeC for 2 hours.
<High-speed stirring type medialess dispersing machine>
Apex Disperser ZERO (trade name: manufactured by Hiroshima Metal & Machinery Co., Ltd.) was used.

<Fiber diameter>
The aqueous dispersions of the resin compositions obtained in Examples and Comparative Examples were observed with a field emission electron microscope (FE-SEM), and an electron micrograph (at 50,000 times) was taken. On the picture taken, two lines crossing with 20 or more nanofibers are drawn at any position across the picture, and the fiber diameters of all nanofibers crossing the lines are measured, and the obtained measured values The average fiber diameter (nm) was calculated as an arithmetic average value of (n = 20 or more). The standard deviation of the fiber diameter distribution and the maximum fiber diameter of nanofibers can also be determined based on the measured values of the fiber diameter.

<Zeta potential measurement method>
1 ml of the aqueous dispersion of the resin composition obtained in Examples and Comparative Examples is placed in a disposable glass test tube, diluted with purified water, and the concentration of unmodified cellulose nanofibers is adjusted to 0.01% by weight. Next, after ultrasonic treatment for 30 minutes, it was subjected to the following zeta potential measurement. The equipment used and the measurement conditions are as follows.
Measuring instrument: Zeta potential, particle size measuring system (manufactured by Otsuka Electronics Co., Ltd.)
Measurement condition: Standard cell SOP for zeta potential
Measurement temperature: 25.0 ° C
Zeta potential conversion formula: Smolchowski's formula Solvent: Water (The parameters of the refractive index, viscosity, and dielectric constant of the solvent apply the values of ELSZ software manufactured by Otsuka Electronics Co., Ltd. as they are.)
System suitability: Latex 262 nm standard solution (0.001%) does not exceed the specified range.

<Gel fraction>
The gel fraction was determined as the degree of crosslinking. The aqueous dispersion of the adhesive reinforcing layer composition obtained in Examples and Comparative Examples is applied by bar coater at a speed of 3 m / s onto base layer A or base layer B which has been subjected to hydrophilization treatment with oxygen plasma, and natural It dried and formed the coating film of 100 mm x 200 mm x 50 micrometers in thickness. The coating film was heated at 170 ° C. for 20 minutes for chemical crosslinking to obtain a crosslinked coating film (crosslinked product of the coating film). The obtained crosslinked coating film was peeled off from the base layer, and the initial dry weight (g) was determined. After immersing a sample obtained by weighing the initial dry weight at room temperature for 24 hours, the dissolution residue was filtered off with a quantitative filter paper, dried at 100 ° C. for 2 hours, and weighed to determine the insoluble weight (g). The gel fraction is calculated from the following equation.
Gel fraction (%) = [(insoluble content weight) / (initial dry weight)] × 100
Further, in physical crosslinking, the laminate coated and adhered on the base material layer was irradiated with 1,000 (mJ / cm ² ) ultraviolet light to cure the reinforcing layer, and the gel fraction was determined in the same manner as described above. .

<Base layer thickness 1.0 mm>
Example 1
Hereinafter, although the compounding quantity of the component used in the form of aqueous solution or aqueous dispersion liquid is shown by solid content, of course these contain water.
To 20 g of PVB resin, 1.9 g of cross-linking agent (TAIC) (9.5 wt% to PVB resin), 0.6 g of unmodified CNF (BiNFi-s) (1 wt% to PVB resin), dispersant (Aron A-6012) 0.03 g (5 wt% relative to unmodified CNF) and 200 ml of purified water were simultaneously loaded into a high-speed rotary medialess disperser (apex disperser ZERO), sheared part clearance 1 mm, rotor Aqueous dispersion of the adhesive reinforcing layer composition of the present invention having a solid content of 10% by weight by setting the rotational peripheral speed to 30 m / s for 5 times and setting the solid content 10% by weight (adhesive reinforcing layer A composition (a)) was prepared. In the adhesive reinforcing layer composition (A), no precipitation of unmodified cellulose nanofibers was observed, and it was a stable slurry, and the zeta potential of the adhesive reinforcing layer composition (A) was -39.7 mV. In addition, the unmodified cellulose nanofiber contained in the adhesive reinforcing layer composition (A) had an average fiber diameter of 25 nm.

  The dispersibility (CNF dispersibility) and the sedimentation stability (CNF sedimentation stability) at the uncrosslinked stage were examined by visual observation for the adhesive reinforcing layer composition (A) which is the obtained aqueous dispersion.

  The dispersibility (CNF dispersibility) is the visual evaluation result of the dispersibility of the unmodified cellulose nanofiber and the adhesive reinforcing layer composition (A) in the aqueous dispersion of the adhesive reinforcing layer composition (A) immediately after preparation. Yes, uniform (no dispersion or aggregation of unmodified cellulose nanofibers or water-soluble crosslinkable resin is observed) that is uniform throughout and does not produce shades of color "○", dark parts are large Those that were partially produced but partially transparent supernatant liquid or had color shades were evaluated as "x".

  Sedimentation stability (CNF sedimentation stability) refers to the result of visual evaluation of the dispersibility of the unmodified cellulose nanofibers and the crosslinkable resin in the adhesivity-reinforcing layer composition (A) aqueous dispersion after standing for 24 hours or more. The sample was evaluated as “○” where no precipitation of unmodified cellulose nanofibers occurred, and as “×” when precipitation of non-modified cellulose nanofibers was slight.

  Adhesive reinforcement layer composition on 3 m / sec conditions with a bar coater on the surface which one side of the substrate layer A made of PC (1.0 × 25 × 75 mm) was cleaned and hydrophilized by oxygen plasma treatment (A) was coated and naturally dried to obtain a 50 μm thick coating film for adhesion. In addition, after performing the same oxygen plasma treatment on one side of the PC base material layer B (1.0 × 25 × 75 mm), the bonding coating surface of the base material layer A and each side are aligned and bonded, The laminate consisting of the material layer A and the base material layer B is uniformly fixed by a plurality of clamps and fixed, held at 80 ° C. for 2 hours for adhesion, and physically crosslinked by irradiation of 30 kGy of γ rays. I got the body (a).

  After the adhesive reinforcing layer composition was applied to the base layer A, the base layer B was not adhered and was crosslinked under the same conditions as described above, and the gel fraction was measured. The gel fraction in this case was 91%.

  An impact test was conducted using the laminate (a). In the impact test, a steel ball of φ 50 (514 g) was dropped from a height of 1000 mm above the horizontally placed laminate (a), and the state of breakage of the laminate a was observed. After the steel balls hit the laminate, those with no cracks on the surface of the base layer are 、, those with cracks but those that do not break the laminate are ○, those with only one upper ball Was evaluated as x, and those in which the steel balls broke both the base material layer A and the base material layer B were evaluated as x. The results are shown in Table 1 as impact resistance.

The bending deflection test was performed as follows using the said laminated body (a). Three points bending test was conducted using Shimadzu Autograph (AGX-Plus, Shimadzu Corp.) under the condition of distance between supporting points (span) 65 mm and test speed 1.0 mm / min. The condition of the laminate when wet was visually evaluated. In the evaluation, both the base material layer A and the base material layer B were not cracked at all ◎, those which were cracked but not cracked were ○, those with only one base material layer broken were Δ, the substrate layer A, base material The thing cracked with the layer B was evaluated as x. Here, “crack” indicates a state in which the base material layer is connected without separation, and “crack” indicates a state in which the base layer is broken and separated.
The impact resistance and the bending deflection test both for which the evaluation result was ◎ or と し た were taken as the application range of the present invention.
In addition, the base material layer A was installed and tested in the impact test and the bending deflection test.

(Example 2)
The adhesive reinforcing layer composition (A) was prepared in the same manner as in Example 1 except that no crosslinking agent was added and no crosslinking treatment was performed in Example 1, and the same evaluation was performed. The obtained aqueous dispersion had a zeta potential of -39.2 mV, and the unmodified CNF contained in the adhesive reinforcing layer composition (i) had an average fiber diameter of 26 nm. The CNF dispersibility and CNF sedimentation stability of the adhesive reinforcing layer composition (B) were both evaluated as "o". The evaluation results of the laminate (b) obtained by the operation are shown in Table 1.

(Example 3)
A laminate (c) was obtained in the same manner as in Example 1 except that the crosslinking agent was changed to carbodilite and the crosslinking treatment was changed to the above-mentioned chemical crosslinking (heating). The zeta potential of the adhesive reinforcing layer composition (c) obtained by this operation was -39, 0 mV, and the average fiber diameter of the unmodified cellulose nanofibers was 25 nm. The evaluation results of the laminate (c) are shown in Table 1.

(Comparative example 1)
In Example 1, the adhesive reinforcing layer composition (d) and the laminate (d) are prepared in the same manner as in Example 1 except that the dispersing agent is not added, and the physical crosslinking treatment is performed, and the same evaluation is performed. went. The results are shown in Table 1.

(Comparative example 2)
In Example 1, the unmodified CNF and the dispersant are not added, but after the crosslinker TAIC is added to obtain an adhesive reinforcing layer composition (O), it is coated on the base layer A treated with oxygen plasma, The laminate was bonded to the base material layer B and subjected to the same physical crosslinking treatment to prepare a laminate (e), and the same evaluation was performed. The results are shown in Table 1.

(Comparative example 3)
The adhesive reinforcing layer composition (f) is prepared in the same manner as in Example 1 except that the dispersing agent and the crosslinking agent are not added, and the composition is coated and laminated on the base material layer without crosslinking treatment. A laminate (f) was produced. After that, the same evaluation was performed. The zeta potential of the adhesive reinforcing layer composition (iv) was −14.4 mV, and the average fiber diameter of unmodified CNF was 26 nm. The results are shown in Table 1.

(Comparative example 4)
In Example 1, similar operations are carried out without addition of unmodified CNF, dispersant and crosslinking agent to prepare an adhesive reinforcing layer composition (i), and after coating on a substrate layer A, crosslinking treatment is carried out. The same evaluation was performed after producing a layered product (g) without. The results are shown in Table 1.

(Examples 4 to 6, Comparative Examples 5 to 8)
Adhesion Reinforcing Layer Composition (A) to Adhesion Reinforcing Layer Composition (a) in Examples 1 to 3 and Comparative Examples 1 to 4 except that the substrate layer A was replaced with PC to make the glass plate. A laminate (h) to a laminate (n) were produced using the above, and the same evaluation was performed. The results are shown in Table 1.

(Examples 7-9, comparative examples 9-12)
Adhesion Reinforcing Layer Composition (A) to Adhesion Reinforcing Layer Composition (Examples 1 to 3) Comparative Examples 1 to 4 except that both the substrate layer A and the substrate layer B were the glass plate The laminate (o) to the laminate (u) were produced using the above), and the same evaluation was performed. The results are shown in Table 1.

(Example 10)
The same procedure as in Example 1 is repeated except that the reinforcing resin is replaced with PVB and a water / ethanol solution with a solid content of 20% by weight of the modified nylon is used to convert the solid content to 20 g and the crosslinking agent is TG-G. Then, the adhesive reinforcing layer composition (G) was prepared, coated on the base material layer and then laminated, and the chemical crosslinking was performed to prepare a laminate (V), and the same evaluation was performed. The zeta potential of the adhesive reinforcing layer composition (v) obtained by this operation was -39, 3 mV, and the average fiber diameter of the unmodified cellulose nanofibers was 25 nm. The results are shown in Table 1.

(Example 11)
The adhesive reinforcing layer composition (iv) was prepared in the same manner as in Example 10 except that the crosslinking agent TG-G was not added and the crosslinking treatment was not performed, and a laminate (w) was obtained. The zeta potential of the adhesive reinforcing layer composition (iv) obtained by this operation was -39, 2 mV, and the average fiber diameter of the unmodified cellulose nanofibers was 26 nm. The results are shown in Table 1.

(Comparative Examples 13 to 16)
In Comparative Examples 1 to 4, except that the resin of the adhesive reinforcing layer composition is replaced with PVB to make a water / ethanol solution of 20% by weight of modified nylon solids, the crosslinking agent is TG-G, and the crosslinking treatment is chemical crosslinking. The same operation was performed, and the same evaluation was performed. The results are shown in Table 1.

(Comparative Examples 17 to 18)
The impact resistance test and the bending deflection test were performed using 2.0 × 25 × 75 mm PC flat plate base layers and glass flat plate base layers, respectively. The results are shown in Table 2.

(Examples 12, 13)
The same evaluation was performed in the same manner as in Example 4 except that the addition amount of the unmodified cellulose nanofibers of the adhesive reinforcing layer composition was changed to 3% by weight and 5% by weight. The results are shown in Table 3.

  From Table 1, in Examples 1 to 11 and Comparative Examples 1 to 16, using the base material layer in which both the thicknesses of the base material layer A and the base material layer B are 1.0 mm, a laminate of PC with each other, PC Laminate of glass and glass, making a laminate of glass, addition effect of unmodified cellulose nanofiber to reinforcing layer with adhesiveness, presence or absence of dispersant, crosslinking method (γ-irradiation, heating) of crosslinking agent Influence of CNF dispersibility, CNF sedimentation stability, gel fraction of reinforcement layer, impact resistance of laminate and bending flexibility of kinds (PVB, modified nylon) of kind (TAIC, carbodilite) reinforcement layer resin was investigated. . As a result, even if it is a laminate of PC base material layers, a laminate of PC base material layer and glass base material layer, or a laminate of glass base material layers, the adhesive reinforcing layer of the laminate is unmodified cellulose. It was confirmed that both of the high dispersibility of nanofibers (adding dispersant) and the impact resistance and bending deflection properties of the cross-linked ones were high and resistant to cracking (Examples 1, 4 and 7). Moreover, it was recognized that the impact resistance and bending-deflection characteristics as a laminate are further improved by the crosslinking treatment when an adhesive reinforcing layer composition having high CNF dispersibility (without adding a dispersant) is used. (Examples 2, 5, 7)

  Moreover, even when denatured nylon was used for reinforcement layer resin, the result similar to the case of PVB was obtained (Examples 10-11, Comparative Examples 13-16).

Furthermore, compared with Examples 1, 4 and 7 and Comparative Examples 17 and 18 (Table 2), compared with the base material layer alone, the laminates according to the present invention have small impact resistance and flexural deflection characteristics and are good. As a result, it can be seen that it is stronger against cracking.
In the combination of the base material layer in the laminate, the combination of PC and PC, the combination of PC and glass, and the combination of glass and glass were both higher in the impact resistance and the bending deflection characteristics.
Moreover, the improvement of impact resistance and bending flexibility was also recognized by apply | coating the said adhesive property reinforcement layer composition to the base material layer of PC single-piece | unit or glass single-piece | unit.

  Moreover, when the addition amount of the cellulose nanofiber of the said reinforcement layer is high in Table 3, compared with Example 4, the evaluation result of impact resistance and bending flexibility improves more, and the effect of a reinforcement layer is a cellulose nanofiber. It becomes high according to the addition amount (Examples 12 and 13).

 In addition, even if the thickness of the substrate layer is changed to 0.1 mm or 2.0 mm, the presence or absence of the dispersant, the presence or absence of crosslinking, the impact resistance depending on the type of crosslinking (physical crosslinking or chemical crosslinking), order of bending flexibility There was no change in

  In Example 1, even when the thickness of the adhesive reinforcing layer composition was 0.005 mm or 1 mm by the casting method, improvement in impact resistance and flexural flexibility was observed.

  In Example 1 and Comparative Example 1, as the dispersant, methacroyloxyethyl phosphorylcholine (co) polymer (Lipidia BL, manufactured by NOF Corporation), or acrylic carboxylic acid copolymer (ARON A-6114, Toho synthesis ( In the same manner as in the above example, the unmodified cellulose nanofiber dispersion, the unmodified cellulose nanofiber sedimentation stability, the gel fraction, and the impact resistance were all obtained. Since the result equivalent to Example 1 and Comparative Example 1 was obtained, the addition effect of the crosslinked and unmodified cellulose nanofibers could be confirmed in any case. The addition amount in this case and the sample preparation conditions were all the same as in Example 1.

Claims (7)

  A laminate comprising a base layer comprising a single layer or two or more layers, and a reinforcing layer, wherein the reinforcing layer is a synthetic resin containing cellulose nanofibers.   The laminate according to claim 1, wherein the reinforcing layer is a cured layer obtained by crosslinking and curing a composition containing a water-soluble or water-dispersible crosslinkable resin and a dispersant.   The laminate according to any one of claims 1 to 2, wherein the composition containing the crosslinkable resin is a composition containing a crosslinking agent or a composition in which the crosslinkable resin is self-crosslinking.   The cross-linking resin of the reinforcing layer is a copolymer of vinyl alcohol and at least one ethylenic double bond-containing compound selected from the group consisting of vinyl acetate, vinyl butyral, acrylic acid, methacrylic acid, and ethylene. The composition according to claim 2, which is a composition comprising at least one selected from the group consisting of a combination or / and a derivative thereof, or a modified polyamide resin soluble in water or alcohol, a cross-linked copolymer polyamide, or a water-soluble epoxy resin. The laminated body of 3.   The laminate according to claim 4, wherein the crosslinkable modified polyamide is one in which the modified polyamide resin is polyethylene glycol modified, N-methoxymethylated modified or carbodiimide modified in a repeating structural unit. .   The thickness of the said reinforcement layer is 0.005 mm-1 mm, The laminated body of Claims 1-5.   The reinforcing layer is a composition comprising cellulose nanofibers and a dispersant, and a composition comprising a hydrophilic solvent, the crosslinkable resin and the crosslinker, or a composition comprising a hydrophilic solvent and the self-crosslinkable resin, The manufacturing method of the layered product which carries out a crosslinking treatment after the process of applying the above-mentioned reinforcement layer on the single side or both sides of one side or two or more base material layers which consist of one side of the base material layer which consists of.