JP2013202909A - Laminate, method of manufacturing the same, and gas barrier material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate hardly causing crease due to contraction by restraining residual stress of a layer containing minute cellulose, a method of manufacturing the same, and a gas barrier material.SOLUTION: In a laminate including a base material formed of a polymer having amide bonding, and minute cellulose layer(s) laminated on one surface or both surfaces of the base material and containing at least minute cellulose, a ratio of thickness per layer of the minute cellulose layers to the thickness of the base material is 0.5-10%. A coating process and a drying process are performed while pulling a length direction or a width direction of the base material, or both of them with force of 1-100N.

Description

  The present invention relates to a laminate, a method for producing the same, and a gas barrier material.

  Containers and packaging materials such as food, toiletry products, medicines, medical products, and electronic materials are required to have strength and gas barrier properties to protect the contents. Most of the gas barrier materials currently used are manufactured from chlorine-based materials such as polyvinylidene chloride and those manufactured by vapor deposition of inorganic substances. Heat is being exhausted. In addition, chlorine-based materials have the problem of generating dioxins, and inorganic deposited films have problems such as damage to the incinerator during incineration and the need to peel off the film during recycling. There was also. For this reason, gas barrier materials are also being converted to environmentally friendly materials that suppress these problems.

  Cellulose is a material that is attracting attention as an environmentally friendly type. Cellulose is contained in plant cell walls, microbial exocrine secretions, and sea squirt mantles, and is the most abundant polysaccharide on the earth. It has biodegradability, high crystallinity, and excellent stability and safety. Therefore, application development is expected in various fields.

  Cellulose has strong intramolecular hydrogen bonds and high crystallinity, so it is almost insoluble in water and common solvents, but research has been actively conducted to improve solubility. Cellulose has three hydroxyl groups, but by performing an oxidation reaction with a TEMPO catalyst system, only the primary carbon at the 6-position of cellulose can be selectively oxidized, converted to a carboxyl group via an aldehyde group, In recent years, it has attracted a great deal of attention because it is possible to carry out the reaction under mild conditions such as aqueous systems and room temperature. TEMPO is an abbreviation for 2,2,6,6-tetramethylpiperidine-1-oxyl (2,2,6,6-tetramethylpiperidine 1-oxyl).

  In addition, when an oxidation reaction is performed on natural cellulose using a TEMPO catalyst system, only the nano-order crystal surface can be oxidized while maintaining the crystallinity of the cellulose. It is known that it can be dispersed in water. It is known that fine cellulose has high strength due to high crystallinity and low linear expansion coefficient, and a film formed by drying the water-dispersed fine cellulose has a gas barrier property.

  As a method for producing a film on which fine cellulose is formed, for example, in Patent Document 1, a gas barrier suspension containing fine cellulose is applied on a base material made of polyamide and dried to form a base material and a gas barrier layer. A method for producing a gas barrier laminate having the same is described.

JP 2011-131458 A

  However, just coating a suspension containing fine cellulose, which has a large shrinkage due to residual stress during drying, on a highly water-absorbing polyamide as it is, the formed coating film shrinks greatly during drying, resulting in a gas barrier laminate. There was a risk of wrinkling.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a laminated body that suppresses residual stress of a layer containing fine cellulose and is unlikely to cause wrinkles due to shrinkage, a manufacturing method thereof, and a gas barrier material. To do.

  In order to solve the above problems, an aspect of the present invention has the following configuration. That is, the laminate according to one embodiment of the present invention is a laminate including a base material made of a polymer having an amide bond and a fine cellulose layer that is laminated on one or both sides of the base material and contains at least fine cellulose. The thickness per layer of the fine cellulose layer with respect to the thickness of the substrate is 0.5% or more and 10% or less.

  In this laminate, the polymer having an amide bond is preferably nylon or a derivative thereof.

  The fine cellulose has a carboxyl group introduced into the crystal surface by an oxidation reaction using an N-oxyl compound, and the amount of the carboxyl group of the fine cellulose is 0.1 mmol / g or more and 3.0 mmol / g or less. preferable.

  Further, the fine cellulose preferably has a number average fiber width of 1 nm to 50 nm and a number average fiber length of 100 times to 10,000 times the number average fiber width.

  Furthermore, the fine cellulose layer preferably contains an inorganic layered mineral.

  Furthermore, it is preferable that the fine cellulose layer contains a water-soluble polymer.

  Furthermore, it is preferable to have an anchor layer between the base material and the fine cellulose layer.

  In addition, a method for manufacturing a laminate according to one embodiment of the present invention includes a base material made of a polymer having an amide bond and a micro cellulose layer that is laminated on one side or both sides of the base material and includes at least fine cellulose. A method for manufacturing a body, wherein a coating liquid is formed by coating a dispersion containing fine cellulose on one or both sides of a substrate, and the coating film is dried to obtain a thickness per layer relative to the thickness of the substrate. And a drying step of forming a fine cellulose layer so as to be 0.5% or more and 10% or less, while pulling the length direction or the width direction of the substrate with a force of 1N or more and 100N or less A coating process and a drying process are performed.

  Moreover, the manufacturing method of the laminated body which concerns on the other aspect of this invention is equipped with the base material which consists of a polymer which has an amide bond, and the fine cellulose layer laminated | stacked on the single side | surface or both surfaces of a base material and containing a fine cellulose at least. A method for producing a laminate comprising: a coating step of coating a dispersion containing fine cellulose on one or both sides of a substrate to form a coating film; And a drying step of forming a fine cellulose layer so that the thickness is 0.5% or more and 10% or less, the mass concentration of the dispersion is 0.1% or more and 5% or less, and the film thickness of the coating film is It is 0.1 μm or more and 500 μm or less.

  Further, the gas barrier material according to one embodiment of the present invention is characterized by using the above laminate.

  According to the laminate of the present invention, it becomes possible to form a fine cellulose layer containing fine cellulose on a substrate made of a polymer having an amide bond by coating. When used as a packaging material, a base material for forming a separately required gas barrier layer is unnecessary, and the production process and materials are reduced, so that the production can be simplified and at low cost. In addition, since shrinkage and wrinkle generation during the coating and drying processes are reduced, defects such as cracks and film thickness unevenness, and defects such as printing and laminating in subsequent processes can be improved.

  Furthermore, according to the method for producing a laminate according to the present invention, when coating and drying a dispersion containing fine cellulose on a substrate made of a polymer having an amide bond, the length direction of the substrate or By pulling in the width direction or both, a laminate in which shrinkage and wrinkle generation are further reduced can be manufactured. Moreover, a residual stress can be further suppressed by making mass density of the said dispersion liquid at the time of coating into 0.1% or more and 10% or less.

Embodiments of a laminate, a method for producing the same, and a gas barrier material according to the present invention will be described in detail.
In the laminate of this embodiment, a fine cellulose layer containing fine cellulose is laminated on one side or both sides of a base material made of a polymer having an amide bond, and the thickness per layer of the fine cellulose layer is 0 with respect to the thickness of the base material. .5% or more and 10% or less.

  The thickness per layer of the fine cellulose layer is 0.5% or more and 10% or less with respect to the thickness of the base material, and the thickness per layer of the fine cellulose layer is small with respect to the thickness of the base material. Residual stress is reduced, and shrinkage and wrinkles can be suppressed.

  Further, the presence of high-strength fine cellulose on the substrate can improve the physical strength (tensile, tearing, piercing, etc.) of the substrate. Furthermore, since the hydrophilic fine cellulose layer exists on the surface of the laminate and is smooth, the printing characteristics of the hydrophilic ink are excellent.

  Such a laminate of this embodiment can be produced by the following method. First, a dispersion containing fine cellulose is coated on one or both sides of a base material made of a polymer having an amide bond to form a coating film (hereinafter referred to as “coating process”). Subsequently, the formed coating film is dried to form a fine cellulose layer so that the thickness per layer with respect to the thickness of the substrate is 0.5% or more and 10% or less (hereinafter referred to as “drying step”). . At this time, a laminate is obtained by performing the coating process and the drying process while pulling the length direction or the width direction of the base material or both of them with a force of 1N or more and 100N or less.

  Moreover, it can manufacture also by another method as follows. A coating process and a drying process are performed similarly to said method. At this time, a laminate is obtained by setting the mass concentration of the dispersion to 0.1% to 10% and the film thickness of the coating to 0.1 μm to 500 μm.

  Also, the above two manufacturing methods can be used together.

  If a laminated body is manufactured by these methods, it is possible to produce a laminated body in which shrinkage and wrinkle generation are suppressed.

  Below, the laminated body concerning this invention, its manufacturing method, and embodiment of a gas barrier material are described still in detail.

(About the base material of the laminate)
The substrate in the laminate of the present invention is a substrate made of a polymer having an amide bond. For example, nylon such as nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 612, nylon 6T, nylon 6I, nylon 9T, nylon M5T, or derivatives thereof. Alternatively, two or more composite materials may be used.

  The shape of the substrate is not particularly limited, and in the case of a film or sheet, the thickness may be 1 μm or more and 1000 μm or less.

(About the fine cellulose layer of the laminate and its production method)
The fine cellulose in the present invention preferably has a carboxyl group introduced into the crystal surface by an oxidation reaction using an N-oxyl compound described later. The carboxyl group amount is preferably 0.1 mmol / g or more and 3.0 mmol / g or less, and more preferably 0.5 mmol / g or more and 2.0 mmol / g or less. If the carboxyl group amount is less than 0.1 mmol / g, it may be difficult to uniformly disperse the fine cellulose without causing electrostatic repulsion. Moreover, when it exceeds 3.0 mmol / g, there exists a possibility that the crystallinity of a fine cellulose may fall.

  Further, the fine cellulose in the present invention preferably has a number average fiber width of 1 nm to 50 nm and a number average fiber length of 100 times to 10000 times the number average fiber width. If the number average fiber width is less than 1 nm, the cellulose will not be in a nanofiber state, and if it exceeds 50 nm, the transparency of the dispersion will be impaired. In addition, when the number average fiber length is less than 100 times the number average fiber width, the strength of the fine cellulose layer may be lowered. When the number average fiber length exceeds 10,000 times, the viscosity of the dispersion becomes very high. There is a risk of problems in workability.

  Next, a method for producing a fine cellulose layer will be described. The fine cellulose layer is a step of oxidizing cellulose, a step of preparing a dispersion by refining the oxidized cellulose, a step of coating the dispersion on a substrate to form a coating, a step of drying the coating, Is obtained.

[About the step of oxidizing cellulose]
As raw materials for cellulose to be oxidized, wood pulp, non-wood pulp, waste paper pulp, cotton, bacterial cellulose, valonia cellulose, squirt cellulose, fine cellulose, microcrystalline cellulose, and the like can be used.

  As a method for modifying cellulose, a method using a co-oxidant in the presence of an N-oxyl compound having a high selectivity to oxidation of a primary hydroxyl group while maintaining the structure as much as possible under relatively mild conditions in an aqueous system. Is desirable. As N-oxyl compounds, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl, 2, 2,6,6-tetramethyl-4-phenoxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-benzylpiperidine-1-oxyl, 2,2,6,6-tetramethyl-4 -Acryloyloxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-methacryloyloxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-benzoyloxypiperidine-1-oxyl 2,2,6,6-tetramethyl-4-cinnamoyloxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-acetyla Nopiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-acryloylaminopiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-methacryloylaminopiperidine-1-oxyl, 2, 2,2,6,6-tetramethyl-4-benzoylaminopiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-cinnamoylaminopiperidine-1-oxyl, 4-propionyloxy-2,2 , 6,6-tetramethylpiperidine-N-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-ethoxy-2,2,6,6-tetramethylpiperidine-N -Oxyl, 4-acetamido-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-oxo-2,2,6,6-tetramethyl Piperidine-N-oxyl, 2,2,4,4-tetramethylazetidine-1-oxyl, 2,2-dimethyl-4,4-dipropylazetidine-1-oxyl, 2,2,5,5- Tetramethylpyrrolidine-N-oxyl, 2,2,5,5-tetramethyl-3-oxopyrrolidine-1-oxyl, 2,2,6,6-tetramethyl-4-acetoxypiperidine-1-oxyl, di-tert -Butylamine-N-oxyl, poly [(6- [1,1,3,3-tetramethylbutyl] amino) -s-triazine-2,4-diyl] [(2,2,6,6-tetramethyl -4-piperidyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imino and the like. Among these, 2,2,6,6-tetramethyl-1-piperidine-N-oxyl and the like are preferably used.

  In addition, as the above-mentioned co-oxidant, the oxidation reaction such as halogen, hypohalous acid, halous acid, perhalogen acid or salts thereof, halogen oxide, nitrogen oxide, peroxide, etc. should be promoted. Any oxidant can be used if possible. Among these, sodium hypochlorite is preferable from the viewpoint of availability and reactivity.

Furthermore, when carried out in the presence of bromide or iodide, the oxidation reaction can proceed smoothly, and the introduction efficiency of the carboxyl group can be improved.
As the N-oxyl compound, TEMPO is preferable, and an amount that functions as a catalyst is sufficient. The bromide is preferably sodium bromide or lithium bromide, and sodium bromide is more preferable from the viewpoint of cost and stability. The amount of the co-oxidant, bromide or iodide used is sufficient if there is an amount capable of promoting the oxidation reaction.

It is more desirable to carry out the reaction under conditions of pH 9 or more and pH 11 or less. However, as the oxidation proceeds, carboxyl groups are generated and the pH in the system is lowered, so it is necessary to keep the system at pH 9 or more and pH 11 or less. There is.
In order to keep the inside of the system alkaline, it can be prepared by adding an alkaline aqueous solution while keeping the pH constant. Examples of the alkaline aqueous solution include sodium hydroxide, lithium hydroxide, potassium hydroxide, aqueous ammonia solution, and organic alkalis such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, and benzyltrimethylammonium hydroxide. Although used, sodium hydroxide is preferred in view of cost.

  In order to complete the oxidation reaction, it is necessary to add the other alcohol while maintaining the pH in the system and complete the reaction of the co-oxidant. The alcohol to be added is preferably a low molecular weight alcohol such as methanol, ethanol, propanol or the like in order to quickly terminate the reaction. In view of the safety of by-products generated by the reaction, ethanol is more preferable.

  Methods for washing oxidized cellulose after oxidation include washing with alkali and salt formed, washing with carboxylic acid by adding acid, washing with insoluble by adding organic solvent, etc. is there. From the viewpoint of handling properties, yield, etc., a method of washing by adding an acid to obtain a carboxylic acid is preferable. The washing solvent is preferably water.

[About the process of refining oxidized cellulose and preparing a dispersion]
As a method for refining oxidized cellulose, first, oxidized cellulose is suspended in various organic solvents such as water and alcohol or a mixed solvent thereof. If necessary, the pH of the dispersion may be adjusted to increase dispersibility. Examples of the alkaline aqueous solution used for pH adjustment include sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia aqueous solution, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, etc. And organic alkalis. Among these, sodium hydroxide is preferable from the viewpoints of cost and availability.

  Subsequently, as a method of physically defibrating, high pressure homogenizer, ultra high pressure homogenizer, ball mill, roll mill, cutter mill, planetary mill, jet mill, attritor, grinder, juicer mixer, homomixer, ultrasonic homogenizer, nanogenizer, underwater It can be miniaturized by using an opposing collision or the like. By performing such a micronization treatment for an arbitrary time or number of times, a fine cellulose-dispersed aqueous solution having a carboxyl group on the surface can be obtained.

  The dispersion of fine cellulose may contain other components than the components used for adjusting the pH and the pH as long as the effects of the present invention are not impaired. The other components are not particularly limited, and can be appropriately selected from known additives depending on the use of the fine cellulose layer. Specifically, organometallic compounds such as alkoxysilanes or hydrolysates thereof, inorganic layered compounds, inorganic needle minerals, leveling agents, antifoaming agents, water-soluble polymers, synthetic polymers, inorganic particles, organic particles , Lubricants, antistatic agents, ultraviolet absorbers, dyes, pigments, stabilizers, magnetic powders, orientation promoters, plasticizers, crosslinking agents and the like. Among these, the inorganic layered compound is preferable because it promotes the surface orientation of the film (fine cellulose layer) and improves water resistance, moisture resistance, gas barrier properties and the like.

  The water-soluble polymer is not particularly limited, but by containing the water-soluble polymer in the dispersion, it functions as a buffer material between the fine celluloses and suppresses shrinkage of the fine cellulose due to drying. it can. Furthermore, when used as a gas barrier material, it is more preferable if the water-soluble polymer has gas barrier properties. Examples of the water-soluble polymer include polyvinyl alcohol.

  The inorganic layered compound refers to a crystalline inorganic compound having a layered structure, and as long as it is an inorganic layered compound, its type, particle size, aspect ratio, etc. are not particularly limited, and should be appropriately selected according to the purpose of use and the like. Can do. Specific examples of the inorganic layered compound include clay minerals typified by kaolinite group, smectite group, mica group and the like. Among these, montmorillonite, hectorite, saponite, etc. are mentioned as the smectite group inorganic layered compound. Among these, montmorillonite is preferable from the viewpoints of dispersion stability in the composition, coating properties of the composition, and the like.

The inorganic layered compound may be blended directly in the dispersion, or may be blended after being previously dispersed in an aqueous medium such as water.
Moreover, it is preferable to add an inorganic layered mineral in the range of 0.1 mass% or more and 50 mass% or less with respect to fine cellulose.

  In the present invention, the mass concentration of the dispersion is preferably from 0.1% to 5%. When the mass concentration of the dispersion is 0.1% or less, for example, when used as a gas barrier material, sufficient gas barrier properties cannot be obtained. On the other hand, if the content is 5% or more, the viscosity of the dispersion becomes too high to be coated on the substrate. The mass concentration of the dispersion is the mass concentration of fine cellulose (solid content) contained in the dispersion. When the dispersion contains other components other than fine cellulose, such as inorganic layered compounds, It is the mass concentration of the total solid content combining fine cellulose and other components.

[About the process of forming a coating film by coating a dispersion on a substrate]
As a method of coating a dispersion containing fine cellulose of the present invention on a substrate, a comma coater, a roll coater, a reverse roll coater, a direct gravure coater, a reverse gravure coater, an offset gravure coater, a roll kiss coater, a reverse kiss coater, Micro gravure coater, air doctor coater, knife coater, bar coater, wire bar coater, die coater, dip coater, blade coater, brush coater, curtain coater, die slot coater, screen coater, spin coater, spray coater, etc. Or a combination of two or more coating methods can be used. The coating method does not depend on batch type or continuous type.

  In the present invention, when forming a coating film by coating a dispersion on a substrate, the length direction or width direction of the substrate or both of them are 1N or more and 100N or less, more preferably 20N or more and 80N or less. By coating while pulling with force, swelling associated with water penetration into the substrate can be suppressed.

[About the process of drying the coating film]
As a method for drying the coating film formed on the substrate, blow drying at normal temperature, hot air drying by heating, ultraviolet irradiation drying, hot roll drying, infrared irradiation drying, microwave irradiation drying, or the like can be used.

  In the present invention, the film thickness of the coating film formed by coating the base material with the dispersion liquid is preferably 0.1 μm or more and 500 μm or less, more preferably 1 μm or more and 100 μm or less. By making the film thickness of the coating film within the above range, the shrinkage of fine cellulose and the substrate accompanying drying can be suppressed.

In the present invention, when drying the coating film, by drying the substrate in the length direction or the width direction of the substrate or both of them while pulling with a force of 1N to 100N, more preferably 20N to 80N, Shrinkage of fine cellulose and base material accompanying drying can be suppressed.
In addition, it is more preferable to perform operation which pulls a base material with a specific force in both processes of the process of forming a coating film, and the process of drying a coating film.

(Regarding the layer structure of the laminate)
The fine cellulose layer in the laminate of the present invention is laminated on one side or both sides of the substrate depending on the use of the laminate. Moreover, the fine cellulose layer laminated | stacked on a base material may be one layer, and may laminate | stack several layers, for example, may be multilayers, such as two layers and three layers.
The thickness per layer of the fine cellulose layer is preferably 0.5% or more and 10% or less, more preferably 0.2% or more and 5% or less with respect to the thickness of the substrate. By setting the thickness per one layer of the fine cellulose layer in the above range, the fine cellulose layer can be dried while reducing the residual stress accompanying the drying of each layer. In addition, the thickness per one layer of the fine cellulose layer is adjusted in the range of about 0.05 μm to 1 μm according to the thickness of the substrate.

  In the present invention, in order to improve various performances, in each layer constituting the laminate, a thin film layer made of a metal and a metal oxide on the surface and the surface of each layer excluding the base material and the fine cellulose layer, an anchor primer layer Further, an antifouling layer, a printing layer, an antistatic layer or the like may be interposed. The type of each layer is not particularly limited, but when used as a laminate or a gas barrier material according to the present invention, the type of metal or metal oxide is preferably aluminum, aluminum oxide, silica oxide or the like.

  When using an anchor layer between a base material and a fine cellulose layer, it is preferable to contain at least 1 or more types of resin which has a carboxyl group, a sulfonic acid group, an amino group, or a hydroxyl group. When the resin is included, the polarities of the carboxyl group, sulfonic acid group, amino group or hydroxyl group present in the base material or fine cellulose fiber attract each other, and by reacting with the reactive compound contained in the anchor layer, the adhesion In addition, paintability and stability over time are improved. In particular, by including a resin having a carboxyl group, the effect of improving these performances is remarkable due to the interaction between polarities, the covalent bond due to the reaction with the reactive compound contained in the anchor layer, and the synergistic effect thereof. . The resin contained in the anchor layer may have only one type of functional group or a plurality of functional groups. Moreover, you may have functional groups other than the said functional group, if the above-mentioned effect is not inhibited.

  As the resin having these functional groups, a polyester resin, a polyamide resin, a polyimide resin, a polyurethane resin, a polyacrylic acid resin, a polyolefin resin, or a copolymer thereof can be used. These resins may be acid-modified resins, resins modified by oxidation treatment, or resins having the above functional groups or other functional groups introduced by chemical modification. Among these resins, in particular, polyurethane resins, polyacrylic acid resins, and polyester resins are highly effective in improving adhesion and coating properties with fine cellulose fibers. The said resin should just be contained at least 1 type in the anchor layer, and may be contained combining multiple said resin. Moreover, as long as the above-mentioned effect is not inhibited, you may contain in combination with resin other than the said resin.

Moreover, 12 or more are preferable and, as for the acid value of resin contained in an anchor layer, 20 or more are more preferable. The acid value affects the amount of the functional group and the above-described effects. If the acid value is less than 12, the effect of improving adhesion, paintability, and stability over time is small. If it is 20 or more, these effects are high, and the reactivity with the compound contained in the anchor layer is also good. If it is 50 or more, the interaction between polarities is large even if there is no reactive compound or there is little. appear. However, if it is larger than 200, it may affect the water resistance and blocking properties, so 12 or more and 200 or less are more preferable.
In addition, when the resin contained in the anchor layer has a carboxyl group, the carboxyl group forms various salts using metal hydroxides such as sodium hydroxide and potassium hydroxide, organic ammonium such as ammonium and diethylammonium. can do. The state of these carboxyl groups greatly affects the solubility of the resin and the type of solvent. In particular, when a reactive compound described later is included, it is preferable that the carboxyl group of the resin included in the anchor layer forms an ammonium salt or an amine salt because the reaction proceeds at a low temperature. Here, examples of the amine salt include triethylamine salt.
Further, the carboxyl group of the resin contained in the anchor layer is preferable because the reaction proceeds at a low temperature even when it does not form a salt and exists in the carboxyl group state, that is, in the state of “—COOH”.

  The thickness of the anchor layer is preferably 3 nm or more and 10 μm or less. When the thickness is less than 3 nm, the width of the fine cellulose fiber is smaller than that of the fine cellulose fiber, and the number of contacts is reduced. On the other hand, if it exceeds 10 μm, the film is too thick and the efficiency is poor, and warping and curling occur due to distortion of the anchor layer and the fine cellulose fiber layer. From the aspect of warping and curling, 3 nm or more and 5 μm or less are preferable. In particular, 3 nm or more and 2 μm or less are more preferable in terms of cost and drying efficiency.

Furthermore, the anchor layer preferably contains a reactive compound. These reactive compounds promote the reaction with the resin contained in the anchor layer, and may react with a functional group such as a carboxyl group or a hydroxyl group of the fine cellulose fiber, and further with a functional group contained in the substrate. preferable. Due to these synergistic effects, adhesion between layers, coating property, and stability over time can be exhibited. Although it does not specifically limit as a reactive compound, The compound which has a carbodiimide group, an oxazoline group, an isocyanate group, an epoxy group, an amino group etc. is used preferably. Above all, compounds containing carbodiimide groups, oxazoline groups, and isocyanate groups can react efficiently with hydroxyl groups and carboxyl groups contained in the base material, anchor layer, and fine cellulose fiber layer, and can react at low temperatures. Therefore, it exhibits high reactivity when using a base material that is greatly expanded and contracted by heat.
Moreover, since the carbodiimide group and the oxazoline group react slowly at a low temperature such as room temperature, the adhesion between the base material, the anchor layer, and the fine cellulose fiber can be stabilized over time. In particular, by keeping the anchor layer drying temperature at a low temperature of 80 ° C. or less and providing a fine cellulose fiber layer thereon, unreacted carbodiimide groups and oxazoline groups in the anchor layer are It is possible to prevent deterioration and deterioration of adhesion.

Moreover, it is preferable that the molecular weight of these reactive compounds is 1000 or more. When the molecular weight of the reactive compound is less than 1000, the anchor layer becomes brittle, and the adhesion with a layer made of rigid fine cellulose fibers or a hard substrate is not stable and tends to be weak. For example, when a reactive compound having a molecular weight greater than 1000 is used, the strength of the weakest layer as viewed in the thickness direction of the laminate can be kept at 1.5 N or more when measured as the laminate strength.
Further, the upper limit of the molecular weight of the reactive compound is not particularly specified, but can be appropriately adjusted in consideration of the coating solution viscosity, film strength, and thermal characteristics of the anchor layer.

  In the present invention, a resin layer or a sealant layer may be provided on the outermost layer of the laminate. The resin layer or sealant layer is not particularly limited, and examples thereof include a polypropylene film such as an unstretched polypropylene film, and a polyethylene film such as a low density polyethylene film and a linear low density polyethylene film. The thermoplastic resin is usually laminated via an adhesive layer.

  The inside of the fine cellulose maintains high crystallinity without being damaged by mild and selective TEMPO oxidation reaction, and has a length of several hundred nm to several μm. , Physical strength such as tearing and piercing is improved. Furthermore, since a fine cellulose layer having a large amount of carboxyl groups is present on the surface of the laminate, it can react and bond with the compounds contained in the ink and adhesive, and the smoothness is also improved. Process suitability such as process printing and adhesion is improved. In the case of a hydrophilic ink or adhesive, processability is further improved.

  In addition, the laminated body which concerns on this invention can be used for various molded containers, such as a bottle shape, a cylinder shape, and a box shape, besides being used for various films and sheets. It is also suitable as a packaging material.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, the technical scope of this invention is not limited to these embodiment.

<TEMPO oxidation of pulp>
30 g of softwood bleached kraft pulp was suspended in 1800 g of distilled water, a solution in which 0.3 g of TEMPO and 3 g of sodium bromide were dissolved in 200 g of distilled water was added and cooled to 20 ° C. To this, 172 g of a sodium hypochlorite aqueous solution having a concentration of 2 mol / l and a density of 1.15 g / ml was added dropwise to initiate an oxidation reaction. The temperature in the system was always kept at 20 ° C., and the decrease in pH during the reaction was kept at pH 10 by adding a sodium hydroxide aqueous solution having a concentration of 0.5 mol / l. When sodium hydroxide reached 2.85 mmol / g based on the mass of cellulose, a sufficient amount of ethanol was added to stop the reaction. Thereafter, hydrochloric acid was added until the pH reached 1, and washing was sufficiently repeated with distilled water to obtain oxidized pulp.

Measurement of carboxyl group content of oxidized pulp 0.1 g of oxidized pulp and reoxidized pulp obtained by the above TEMPO oxidation were weighed in a solid mass and dispersed in water at a concentration of 1%, and hydrochloric acid was added to adjust the pH to 3. . Thereafter, the amount of carboxyl groups (mmol / g) was determined by conductivity titration using a 0.5 mol / l aqueous sodium hydroxide solution. The result was 1.6 mmol / g.

<Refining of oxidized pulp>
(Production Example 1)
1 g of oxidized pulp obtained by the TEMPO oxidation was dispersed in 99 g of distilled water and adjusted to pH 10 using an aqueous sodium hydroxide solution. The prepared dispersion was refined with a juicer mixer for 60 minutes to obtain a 1% by mass dispersion.

(Production Example 2)
The same amount of a montmorillonite aqueous dispersion having a concentration of 1% by mass as an inorganic compound is mixed with the 1% by mass of the dispersion prepared in Production Example 1 above, followed by dispersion treatment using an ultrasonic homogenizer. Obtained.

(Production Example 3)
Half of the 1% by weight polyvinyl alcohol aqueous dispersion having a concentration of 1% by weight as a water-soluble polymer was mixed with the 1% by weight of the dispersion prepared in Production Example 1 above, and dispersed using an ultrasonic homogenizer. A dispersion was obtained.

-Shape observation The shape of the above-mentioned fine cellulose was observed using an atomic force microscope (AFM). A 1% fine cellulose aqueous dispersion diluted 1000 times was cast on a cleaved surface of mica, dried, observed with a tapping AFM, the fiber height was measured at 10 points, and the average was taken as the number average fiber width. In addition, the fiber length was similarly observed with a tapping AFM, the length in the longitudinal direction of the fiber was measured at 10 points, and the average was defined as the number average fiber length. The number average fiber width was 3.5 nm, and the number average fiber length was 1.3 μm.

(Examples 1-3)
Using a stretched nylon film (ONy: thickness 25 μm) as a base material, the dispersion prepared in Production Examples 1 to 3 is 4% (1 μm) in thickness of the fine cellulose layer with respect to the thickness of the base material using a bar coater. To form a 100 μm coating film. Thereafter, it was sufficiently dried to produce laminates of Examples 1 to 3 comprising a fine cellulose layer and ONy.

(Examples 4 to 6)
Using ONy (thickness 25 μm) as the base material, apply carboxyl group-containing polyester resin / oxazoline aqueous solution as the anchor layer so that the film thickness after drying is 0.3 μm with a bar coater, and then dry sufficiently Further, the dispersions prepared in the above Production Examples 1 to 3 were coated with a bar coater so that the thickness of the fine cellulose layer was 4% (1 μm) with respect to the thickness of the base material to form a 100 μm coating film. Thereafter, it was sufficiently dried to produce laminates of Examples 4 to 6 comprising a fine cellulose layer, an anchor layer and ONy.

(Examples 7 to 9)
Using ONy (thickness: 25 μm) as the base material, the dispersion prepared in Production Examples 1 to 3 was finely divided with respect to the thickness of the base material with a bar coater while pulling from both sides with a force of 30 N in the length direction of the base material. Coating was performed so that the thickness of the layer was 4% (1 μm) to form a 100 μm coating film. Then, it was fully dried while pulling from both sides with a force of 30 N in the length direction of the base material, and laminates of Examples 7 to 9 made of a fine cellulose layer and ONy were produced.

(Examples 10 and 11)
Using a stretched nylon film (ONy: thickness 25 μm) as a base material, the thickness of the fine cellulose layer with respect to the thickness of the base material is 0.5% (0.125 μm) with a bar coater. Coating was carried out to 1% (0.25 μm) to form coating films of 12.5 μm and 25 μm, respectively. Thereafter, it was sufficiently dried to produce laminates of Examples 13 and 14 comprising a fine cellulose layer and ONy.

(Comparative Examples 1-3)
In Examples 1 to 3, the thickness of the fine cellulose layer was 20% (5 μm) with respect to the thickness of the base material, and the same method as in Comparative Examples 1 to 3 was performed except that a 500 μm coating film was formed. A laminate was produced.

(Comparative Example 4)
In Example 1 above, the same method was used except that the fine cellulose layer was coated so that the thickness of the fine cellulose layer was 0.1% (0.025 μm) and a 2.5 μm coating film was formed. 4 laminates were produced.

-Shrinkage evaluation About each laminated body produced in the said Examples 1-14 and Comparative Examples 1-4, the length of the width direction of a laminated body and the length of the width direction of the original base material were measured, and the following The shrinkage ratio with respect to the original base material was calculated by the calculation formula. The results are shown in Table 1.
{1- (Length in the width direction of the laminate) / (Length in the width direction of the original base material)} × 100

-Measurement of oxygen permeability About each laminated body produced in the said Examples 1-14 and Comparative Examples 1-4, oxygen permeability was measured using the oxygen permeability measuring apparatus (MOCON OX-TRAN 2/21 by Modern Control). The rate (cc / m ² · day) was measured in an atmosphere at a temperature of 30 ° C. and a relative humidity of 40% RH. The results are shown in Tables 1 and 2.

  As can be seen from the results in Tables 1 and 2, when preparing a laminate, adjusting the dry thickness and wet thickness of the fine cellulose layer, applying tension to the substrate during coating and drying, By providing an anchor layer between the material and the fine cellulose layer, it becomes possible to produce a laminate that suppresses shrinkage, and exhibits good barrier properties because cracks and uneven coating due to shrinkage are reduced. Became possible.

Claims (10)

A laminate comprising a base material made of a polymer having an amide bond, and a fine cellulose layer that is laminated on one or both sides of the base material and contains at least fine cellulose,
A laminate having a thickness per layer of the fine cellulose layer with respect to the thickness of the substrate of 0.5% or more and 10% or less.   The laminate according to claim 1, wherein the polymer having an amide bond is nylon or a derivative thereof.   The fine cellulose has a carboxyl group introduced into the crystal surface by an oxidation reaction using an N-oxyl compound, and the amount of the carboxyl group of the fine cellulose is from 0.1 mmol / g to 3.0 mmol / g. The laminate according to claim 1 or 2, wherein the laminate is characterized.   The number average fiber width of the fine cellulose is 1 nm or more and 50 nm or less, and the number average fiber length is 100 times or more and 10,000 times or less of the number average fiber width. The laminated body as described in.   The laminate according to any one of claims 1 to 4, wherein the fine cellulose layer contains an inorganic layered mineral.   The laminate according to any one of claims 1 to 5, wherein the fine cellulose layer contains a water-soluble polymer.   It has an anchor layer between the said base material and the said fine cellulose layer, The laminated body as described in any one of Claim 1 to 6 characterized by the above-mentioned. A method for producing a laminate comprising a substrate made of a polymer having an amide bond, and a fine cellulose layer that is laminated on one or both sides of the substrate and contains at least fine cellulose,
A coating step of coating a dispersion containing the fine cellulose on one or both sides of the substrate to form a coating film;
Drying the coating film, and forming the fine cellulose layer so that the thickness per layer with respect to the thickness of the substrate is 0.5% or more and 10% or less;
With
A method for producing a laminate, comprising performing a coating step and a drying step while pulling a length direction or a width direction of a base material or both of them with a force of 1N to 100N. A method for producing a laminate comprising a substrate made of a polymer having an amide bond, and a fine cellulose layer that is laminated on one or both sides of the substrate and contains at least fine cellulose,
A coating step of coating a dispersion containing the fine cellulose on one or both sides of the substrate to form a coating film;
Drying the coating film, and forming the fine cellulose layer so that the thickness per layer with respect to the thickness of the substrate is 0.5% or more and 10% or less;
With
The method for producing a laminate, wherein the dispersion has a mass concentration of 0.1% or more and 5% or less, and a film thickness of the coating film is 0.1 μm or more and 500 μm or less.   A gas barrier material using the laminate according to any one of claims 1 to 7.