JP6622563B2 - Laminated body - Google Patents

Description

  The present invention relates to a laminate using a cellulosic member.

  Conventionally, for example, a cellulosic member made of a composite material of cellulose microfibrils and an additive is known as an outer plate member used for an outer surface of a vehicle (see Patent Document 1).

  The composite material described in Patent Document 1 is composed of a fiber material composed of cellulose microfibrils and a resin that holds the fiber material, and is lightweight, high-strength, exhibits an excellent appearance, and has an environmental problem. It is described that it is useful also from the viewpoint of.

JP 2006-312281 A

  However, the conventional cellulosic member is easy to absorb moisture, and there is a problem that the strength of the cellulosic member is likely to be reduced by absorbing a large amount of moisture.

  This invention provides the laminated body which can reduce the moisture absorption of a cellulosic member.

In the laminate of the present invention, a foil-like metal layer covering the entire surface is disposed on at least one main surface of the cellulosic member, and the porous layer member is interposed between the cellulosic member and the metal layer. It is characterized by having .

  According to the laminate of the present invention, moisture absorption of the cellulosic member can be suppressed by the metal layer.

(A) is sectional drawing which shows the laminated body which concerns on one Embodiment of this invention, (b) is sectional drawing which expands and shows a part of (a), (c) is a cross section which shows a cellulosic member FIG. (A)-(d) is explanatory drawing for demonstrating the manufacturing method of a laminated body. (A)-(e) is explanatory drawing for demonstrating the other manufacturing method of a laminated body. (A) is explanatory drawing for demonstrating the manufacturing method of a cylindrical laminated body, (b) is a perspective view which shows a cylindrical laminated body. (A) is sectional drawing which shows the laminated body which coat | covered both main surfaces of the cellulosic member with the metal layer, (b) is sectional drawing which shows the laminated body which coat | covered both main surfaces of the flat-plate-like cellulosic member with the metal layer. (C) is sectional drawing which shows the laminated body which coat | covered the side surface of the cellulosic member with the metal layer.

  Hereinafter, the laminated body which concerns on one Embodiment of this invention is demonstrated, referring FIG. The present invention is not limited to the following embodiments, and various changes and improvements can be made without departing from the scope of the present invention.

1A and 1B are cross-sectional views of a laminate, and a cellulosic member 2 is configured by having a porous layer member 3 on the outer surface of a cellulose main body 1 having a semicircular cross section. A metal layer 7 is disposed on the surface of the cellulosic member 2 on the porous layer member 3 side, that is, on the outer surface, with the adhesive layer 5 interposed.

  The cellulose main body 1 has a shape in which a cylinder is halved and is mainly composed of cellulose, and includes at least one of cellulose microfibrils and cellulose nanofibers. In addition to cellulose, the cellulose body 1 can contain hemicellulose and lignin contained in the raw material wood when producing cellulose microfibrils from plants such as wood and bamboo. It is desirable that the content of lignin is 5% by mass or less, desirably 3% by mass or less. It is desirable that the cellulose in the cellulose body 1 contains 90% by mass or more, more desirably 95% by mass or more in the total amount. The cellulose body 1 may be impregnated with about 5% by mass to 10% by mass of a thermosetting resin. The water content of the cellulose body 1 is desirably 6% or less.

  Cellulose microfibrils are microfibrillated cellulose fibers. Microfibrillation is a phenomenon in which microfibrils (microfibers) in fibers appear on the surface due to friction and become fuzzy. Specifically, when a strong mechanical shearing force is applied to the cellulose fibers to form microfibrils, the cellulose fibers are torn into tens of thousands and subdivided into fiber diameters of 0.01 μm to 0.1 μm. It is a phenomenon.

The kind of cellulose microfibril used in the present invention is not limited, and examples thereof include microorganisms such as acetic acid bacteria, animals such as sea squirts, and plants derived from plants such as wood and bamboo. It is preferable to use plant-derived microfibrils from the viewpoint of easily securing the necessary amount and protecting the global environment. The microfibril in this invention can be obtained by a well-known method, and is not limited to the manufacturing method of a microfibril. For example, cellulose microfibrils can be obtained by making pulp fine fiber. The kind of pulp as used herein is not limited in kind, such as kraft pulp, sulfite pulp and the like, chemical pulp obtained by chemical treatment from wood. Cellulose nanofibers that are produced by catalytic treatment of pulp, such as the TEMPO oxidation method, can be used.

  The porous layer member 3 only needs to have heat resistance and allow moisture to permeate. For example, the porous layer member 3 is made of paper, woven fabric, or non-woven fabric. The heat resistance may be, for example, a glass transition point of 130 ° C. or higher. In addition to paper pulp, resin fibers such as aramid, glass fibers, carbon fibers, and the like are used. It is desirable to use a pulp-based material from the viewpoint of cost and environmental protection. The porous layer member 3 is disposed on the entire surface of at least one main surface of the cellulose main body 1, and the portion having moisture permeability is preferably formed on the entire surface of the porous layer member 3. Moreover, the part which has a water permeability may be formed in the porous layer member 3 at radial or grid | lattice form.

  As shown in FIG. 1C, at least a part of the porous layer member 3 is embedded in the cellulose body 1, and a part of the surface protrudes from the outer surface of the cellulose body 1 and is exposed. Thereby, the surface of the cellulosic member 2 on the porous layer member 3 side is uneven.

  It is desirable that the porous layer member 3 has a thickness of 50 μm to 1 mm, an opening diameter of 5 μm to 500 μm, and a porosity of 20% to 50% from the viewpoint of controlling moisture permeation.

  When the thickness of the porous layer member 3 is 50 μm to 1 mm, moisture permeation becomes easy due to the porous layer member 3 having an appropriate thickness, drying time can be shortened, and productivity can be improved. . In addition, the thickness (height) of the product does not increase, and a decrease in strength per weight can be reduced. The ratio of the thickness of the porous layer member 3 to the thickness of the cellulose body 1 is preferably 0.05 to 0.5.

  When the diameter of the opening of the porous layer member 3 is 5 μm to 500 μm, the diameter of the opening is too small, so that the cellulose microfibrils are prevented from closing the opening, and the diameter of the opening is too large. It is possible to reduce clogging due to intrusion of the cellulose microfibrils into the opening and to sufficiently permeate moisture.

  If the porosity of the porous layer member 3 is 20% to 50%, even if the pores are crushed by pressing, moisture can be sufficiently transmitted.

  If the material constituting the porous layer member 3 also has water absorption, the moisture permeability is further improved. Aramid, polyimide, cellulose (paper), cellophane, etc. are preferably used as the material having water absorption. It is desirable to use paper from the viewpoint of environmental protection, and Japanese paper is preferably used from the viewpoint of air permeability and ease of handling (hard to tear and soft).

  The cellulose body 1 here includes, for example, at least one of cellulose microfibrils and cellulose nanofibers, hemicellulose, lignin, and moisture. The main component is cellulose microfibril, and the cellulose nanofiber should just be contained 1-30 mass% of the whole cellulose. Since cellulose nanofibers are fine, they have strong mutual bonding strength, and have the effect of glue that binds cellulose microfibrils to each other, and are effective in improving the strength of cellulose body 1.

The porous layer member 3 is formed in a film shape or a layer shape on at least one main surface of the cellulose main body 1, and is adhered to the cellulose main body 1 by the effect of cellulose nanofiber, hemicellulose, lignin or the like. If an adhesive force is required, an adhesive may be applied between the cellulose body 1 and the porous layer member 3. Further, when removing the porous layer member 3, the content of cellulose nanofiber or hemicellulose or lignin is decreased to weaken the adhesive strength with the cellulose main body 1 and facilitate removal of the porous layer member 3. it can.

  FIG. 1B shows a laminate formed by adhering a metal layer 7 to the surface of the cellulosic member 2 on the porous layer member 3 side, that is, the outer surface of the cellulosic member 2 via the adhesive layer 5. The metal layer 7 is preferably made of a metal foil. As metal foil, aluminum, copper, iron, nickel, and these alloys are desirable, and it is desirable that thickness is 12-400 micrometers. Thereby, it is easy to form the laminate into a three-dimensional shape, and the weight can be reduced.

  As the metal foil, aluminum is preferably used because of its light weight and ease of processing. Further, copper has an effect that copper ions permeate into the cellulose main body 1 in the press step described later, and can impart corrosion resistance and fungicidal properties to the cellulose main body 1. If an alloy of iron or nickel, such as iron, nickel, or stainless steel, is used, rigidity may be imparted, so that the whole may be thinned. Further, corrosion due to metal oxidation can be prevented.

  As the adhesive constituting the adhesive layer 5, various adhesives such as epoxy, urethane, vinyl acetate, acrylic and rubber can be used. Since processing such as coating is easy, water-soluble adhesives such as urethane, vinyl acetate, and acrylic water-based emulsions and gelatin can be used. As shown in FIG. 1B, the adhesive enters the pores of the porous layer member 3, adheres to the cellulose body 1, and adheres to the metal layer 7. Thereby, the metal layer 7 can be firmly bonded to the cellulosic member 2.

Further, even when the porous layer member 3 is removed, a part of the porous layer member 3 remains in the cellulose body 1 without being removed, or the porous layer member 3 is removed so that the surface of the cellulose body 1 is removed. Since the trace remains as the concave portion, the adhesion force of the metal layer 7 to the cellulosic member 2 by the adhesive layer 5 can be improved.

  Further, the shape and function of the metal layer 7 are not limited, and may be in accordance with the form of various devices to which the metal layer 7 is applied, but the exposed surface is a vehicle body surface portion of a vehicle such as an automobile. Is particularly desirable.

  Since the cellulosic member 2 is used in the laminate of the present invention, the strength is high and the weight is light. Therefore, the strength and weight standards required for the vehicle can be satisfied. Furthermore, since it is lightweight, fuel consumption can also be improved. And since it has the metal layer 7 in an outer surface, the penetration | invasion of the water | moisture content from the part in which the metal layer 7 was formed can be prevented, the moisture absorption of the cellulosic member 2 can be reduced, and a strength fall can be suppressed. Further, since the intrusion of moisture can be prevented, the volume of the laminated body does not increase, so that cracks associated with deformation do not occur, and the dimensional accuracy of the laminated body can be maintained high. For this reason, strength reduction and deformation do not occur even in a hot and humid environment, and it can be used outdoors such as an automobile outer plate.

  The laminate of the present invention can be used as an automobile part (for example, an aero part) as described above. Furthermore, it can be used as a member for which high designability is required, such as an outer plate of an electric appliance such as a refrigerator, a paving material or interior material for construction, office supplies such as a bookshelf, furniture such as a desk. It can also be used for structural members such as pipes and plates, and frames, cases, containers, etc. of devices.

  The laminate may further form a surface coating layer or the like painted on the surface of the metal layer 7. The shape of the laminate can be arbitrarily selected. Moreover, the porous layer member 3 should just be arrange | positioned at the at least one main surface of the cellulose main body 1, and it can select arbitrarily in which surface of the cellulose main body 1 it forms. The porous layer member 3 may be disposed on both main surfaces of the cellulose main body 1. The shape of the laminated body can be arbitrarily processed by making the press mold described later into an arbitrary shape.

  Next, the manufacturing method of a laminated body is demonstrated using FIG. First, as shown in FIG. 2 (a), a dispersion 11 containing water and cellulose is put in a container, and the surface of the dispersion 11 is air permeable (moisture permeable) such as paper, nonwoven fabric or woven fabric. The porous layer member 3 is disposed. The cellulose concentration in the dispersion 11 is preferably about 0.5% by mass to 5% by mass, particularly about 1.5% by mass to 2.5% by mass.

  Then, as shown in FIG.2 (b), it is made to dry to below predetermined | prescribed moisture content, for example, 7% or less with the dryer hold | maintained at 30 degreeC-70 degreeC, and the plate-shaped solid body 14 is obtained. The amount of water can be measured by heating the sample in a vacuum at 120 ° C. for 24 hours and measuring the weight before and after the treatment. At this time, if the porous layer member 3 is disposed on the surface of the dispersion 11, deformation and cracking during drying can be prevented.

  That is, since the water in the dispersion 11 first evaporates from the surface, the surface of the dispersion 11 shrinks with a small amount of water, whereas the bottom has a large amount of water and shrinks. Due to the difference in the dry state, the cellulose body 1 is likely to be deformed or cracked. However, since the porous layer member 3 suppresses surface shrinkage, the occurrence of deformation and cracks can be suppressed. Moreover, although the evaporation amount of the water from the dispersion liquid 11 changes with places, generation | occurrence | production of a deformation | transformation and a crack can be suppressed also by equalizing the evaporation amount of a water | moisture content with the porous layer member 3. FIG. Furthermore, even if the porous layer member 3 has a function as a reinforcing layer, the occurrence of deformation and cracks can be suppressed.

  Thereby, even in the case of a material having a high cellulose content and high strength, deformation during processing can be suppressed, so that workability of the material can be ensured, and thus productivity of a high-strength member can be improved.

  In addition, instead of the method of putting in a container and drying, you may dry, after reducing a water | moisture content to about 40%-70% of moisture with a filter press etc. and shape | molding in plate shape.

  Thereafter, as shown in FIG. 2C, a solid body 14 having a metal layer 7 made of metal foil and a porous layer member 3 on the lower surface is disposed on the lower mold 13. Alternatively, the metal layer 7 is temporarily bonded to the solid body 14 having the porous layer member 3 with an adhesive, and this is disposed on the lower mold 13.

  And it presses with the upper mold | type 15, and as shown in FIG.2 (d), the solid body 14 is pressurized and shape | molded in a predetermined shape. Water in the solid body 14 is released through the porous layer member 3. Although the press may be performed once, in the case of a shape with large irregularities, cellulose and metal foil may be broken if processed at once, so it is desirable to perform the process in multiple steps. It is also effective for preventing cracks to process the concavo-convex shape in multiple stages with respect to the target shape using a plurality of molds. The pressing pressure can be 0.1 MPa to 50 MPa. The holding time of the press in a pressurized state is about 1 minute to 5 minutes.

  The press includes at least one hot press at 80 ° C. to 150 ° C. At this temperature, moisture in the solid body 14 evaporates and is discharged to the outside through the porous layer member 3. Thereby, the moisture content of the solid body 14 can be reduced to 6% or less, and a press-formed product having a predetermined shape as shown in FIG. 2D can be obtained.

  A groove or hole for discharging water vapor may be formed in at least one of the lower mold 13 and the upper mold 15. The grooves can be formed in a radial shape or a lattice shape. Moreover, the shape of the lower mold | type 13 and the upper mold | type 15 can be selected arbitrarily.

  FIG. 3 illustrates another manufacturing method of the laminate. The difference from the manufacturing method of FIG. 2 is that the solid body 14 once dried absorbs water as shown in FIG. The amount of water in the solid body 14 when absorbed is, for example, 30% to 70%. The water-absorbed solid body 14 is molded using the lower mold 13 and the upper mold 15. Even if the dispersion 11 is once dried, the solid body 14 that can be easily molded by pressing can be obtained by absorbing water again.

  This method has the feature that the material can be easily stored during the manufacturing process. Water-absorbed cellulose microfibrils often require refrigerated storage to prevent the growth of mold and bacteria. When the dispersion 11 is dried once to obtain a dried solid body 14, refrigerated storage is not required, and storage is facilitated because it does not contain moisture and is light.

  2 and 3, the porous layer member 3 remains in the cellulosic member 2. However, the porous layer member 3 may be removed from the cellulose body 1. In this case, the metal layer 7 is bonded to the cellulose body 1 via an adhesive.

  As shown in FIG. 4 (a), two laminated bodies having a semicircular cross section can be joined with an adhesive to produce a cylindrical laminated body as shown in FIG. 4 (b). In this laminated body, the metal layer 7 is provided on the outer surface of the hollow cellulosic member 2. It is desirable that the metal layer 7 covers the entire outer surface of the hollow cellulosic member 2. Thereby, the moisture absorption in the cellulosic member 2 can further be suppressed, and the strength reduction of the laminate can be suppressed.

  Moreover, as shown to Fig.5 (a), not only the metal layer 7a of the outer surface of the cellulosic member 2, but the metal layer 7b can be formed also in an inner surface. Thereby, the moisture absorption of the cellulosic member 2 can further be suppressed.

In this laminated body, the cross section is not limited to a semicircular shape, but may be a flat laminated body as shown in FIG. 5B and does not need to be hollow. In such a case, both main surfaces of the cellulosic member 2 are covered with the metal layers 7a and 7b, but the side surfaces (side surfaces extending in the thickness direction) are exposed on the side surfaces of the cellulose main body 1. May absorb moisture. For this reason, as shown in FIG.5 (c), you may make it coat | cover the metal layer 7b of the inner surface of the cellulosic member 2 to a side surface. That is, the entire peripheral surface of the cellulosic member 2 is covered with the metal layers 7a and 7b.

  Needless to say, the metal layer 7a on the outer side surface of the cellulosic member 2 may be covered up to the side surface. Furthermore, the metal layer 7b on the inner side surface of the cellulosic member 2 may be covered up to the side surface, and the metal layer 7b on the side surface may be further covered with the metal layer 7a on the outer side surface of the cellulosic member 2. Alternatively, the metal foil may be made longer than the cellulosic member 2 at the portion where the laminate is joined, the metal foils are brought into contact with each other at the joined portion, and the metal foil may be wound. Intrusion of moisture can be further prevented by winding the metal foil.

  In the case of a completely closed hollow laminate, for example, a hollow cylinder, a hollow sphere, a hollow plate, etc. in which both ends of the cylindrical laminate shown in FIG. The inner surface of the material member 2 may not be covered with the metal layer 7. Such a hollow body can be suitably used as, for example, an aero part of a vehicle.

  Moreover, although the metal layer 7 was arrange | positioned through the contact bonding layer on the cellulosic member 2, it is desirable to have a some protrusion in the cellulose layer 2 side of the metal layer 7. FIG. Thereby, the joint strength between the metal layer 7 and the adhesive layer 5 can be increased, the joint strength between the metal layer 7 and the cellulosic member 2 can be improved, and peeling due to aging can be prevented. The protrusion can be formed by plating the same material as the metal foil, etching, polishing, or the like.

  It is desirable that the protrusion has a height of 0.3 μm or more. By forming unevenness of 1 to 20 μm, peeling due to aging can be prevented. When the height of the protrusion exceeds 5 μm, moisture is removed from the interface between the copper foil and the adhesive during the hot pressing process, and the drying efficiency can be increased.

DESCRIPTION OF SYMBOLS 1 Cellulose main body 2 Cellulosic member 3 Porous layer member 5 Adhesive layer 7, 7a, 7b Metal layer 11 Dispersion liquid 14 Solid body

Claims (5)

A foil-like metal layer covering the entire surface is disposed on at least one main surface of the cellulosic member, and a porous layer member is provided between the cellulosic member and the metal layer. A featured laminate.   The laminate according to claim 1, wherein the metal layer is disposed on an outer surface of the hollow cellulosic member.   The laminate according to claim 1 or 2, wherein the metal layer covers the entire outer surface of the hollow cellulosic member.   The laminate according to any one of claims 1 to 3, wherein the metal layer has a plurality of protrusions on the cellulosic member side.   The laminate according to any one of claims 1 to 4, wherein the metal layer is disposed on the cellulosic member via an adhesive layer.

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