JP4378441B2 - Method for producing laminated molded body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a laminated molded article suitable for fibers, particularly fibers regenerated from waste paper.
[0002]
[Prior art]
Many so-called papers such as newspapers, magazines, flyers, printing papers, and copy papers are made of pulp. These retain the fiber structure of the wood itself, and process the used paper, so-called waste paper, to make it a higher-strength material, or stir it in an aqueous solvent to produce a slurry-like pulp. It is known that it can be reproduced. For example, as a method of using waste paper, a method of using it as a raw material for boards used for various purposes such as formwork and wall materials has been proposed (see, for example, Patent Document 1). In this method, a thermosetting resin such as a phenol resin is mixed with a slurry of recycled pulp, and this is heated and pressed at a temperature equal to or higher than the thermosetting temperature in a state where a plurality of sheets made of paper, pressed and dried are stacked. The board can be manufactured.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-239918
[Problems to be solved by the invention]
However, in this method, the dimensional stability is not so high, and warping and bending may occur after molding. In addition, the peel strength between the stacked sheets before molding is small, and particularly in an environment where the sheets are easily immersed in water or wet easily, they are easily peeled off.
Therefore, an object of the present invention is to provide a method for producing a laminated molded body using pulp while suppressing deformability.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is a method for producing a laminated molded body, wherein a papermaking containing 70% by weight or more of fibers derived from natural fibers is immersed in a thermosetting binder solution, and the papermaking is pressed and dried. And remove moisture. Moreover, the manufacturing method of this laminated molded body provides the binder which immerses the said papermaking in a thermosetting binder liquid, and dries the said papermaking at the temperature lower than the curing temperature of the said thermosetting binder. Then, after laminating the desired number of papers, the desired number of laminates are integrated by heating and pressing at a temperature equal to or higher than the curing temperature of the thermosetting binder, and the integrated laminate is pressurized and compressed. By maintaining the state and cooling to a temperature at which the expansion rate of the laminate when the compressed state is released is 2% or less, deformation that occurs after pressure release after the molding can be reduced. In addition, it is possible to obtain a laminated molded body having small deformation such as warpage, bending, and distortion.
Further, in the method for producing a laminated molded body according to claim 2, the integrated laminated body is pressurized to maintain a compressed state and cooled to a temperature of 50 ° C. or lower until the temperature is reduced to 50 ° C. or lower. Deformation that occurs after pressure release can be reduced, and a laminated molded body with less deformation such as warping, bending, and distortion can be obtained.
Further, in the method for producing a laminated molded article according to claim 3, when papermaking having a water content of 5% or less is immersed in a thermosetting binder liquid, the impregnation of the thermosetting binder liquid into the papermaking can be made uniform and good. And dimensional stability can be improved.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the method for producing a laminated molded body of the present invention, various boards can be produced, and is particularly suitable for the production of boards that require strength, rigidity, heat resistance and the like. For example, it is suitable for manufacturing boards used as building floor materials, desk tops, and furniture structural materials. In particular, a laminated molded body produced by applying a sheet on which at least one surface is printed can be suitably used for a visually recognized part. In addition, a laminated molded body produced by providing a sheet that enhances the holding power of nails, screws, etc. on at least one surface is preferable for use as a board on which screws, nails, etc. are struck. Screwing to the leg is possible.
[0007]
Embodiment of this manufacturing method is described in detail with reference to FIGS. The manufacturing method shown in FIG. 1 includes a layered body forming step 1 and a forming step 3 roughly. Hereinafter, each step will be described in detail.
[0008]
(Layer body forming process)
Layer body formation process 1 forms a layer body which forms each layer of a layered fabrication object. As shown in FIG. 1, the layered body forming step 1 includes a paper making process S1, a pressing / drying process S3, a binder applying process S5, and a drying process S7.
[0009]
Materials that can be used as a raw material for papermaking include at least 70% by weight of pulp. As the pulp, virgin pulp may be used, but recycled pulp regenerated from waste paper can be suitably used. Used paper for recycled pulp is so-called paper such as newspapers, telephone books, magazines, cardboard, flyers, wrapping paper, copy paper and printing paper used in offices, and paper products derived from pulp, such as paper diapers. The relevant part or paper napkin. The virgin pulp and the pulp constituting the waste paper are not particularly limited, and may be mechanical pulp, semi-chemical pulp, chemimechanical pulp, or chemical pulp. In order to improve the yield, it is preferable to use chemical pulp with less lignin. Moreover, about the layer body which is not exposed to both surfaces among the several layer body formed at the layer body formation process 1, when not adjusting a physical property, you may utilize what is not bleached. Generally, recycled pulp is obtained by appropriately pulverizing waste paper with a refiner or the like, and then performing deinking treatment, dust removal treatment, and removal of impurities such as fasteners and adhesives.
[0010]
In addition to pulp, the raw material for papermaking may contain resin-based materials such as resins, elastomers, and rubbers. For example, a resin film integrated with a pulp sheet with a paper diaper may be mixed. The resin material preferably has a size and flexibility that do not hinder the formation of paper. For example, it is preferable to reduce the particle size, flake shape, or the like by crushing or cutting. The resin-based material is 30% by weight or less of the entire papermaking raw material. If it exceeds 30% by weight, the formation of papermaking may be hindered or the physical properties of the resulting laminated molded article may be deteriorated.
It should be noted that known additives such as inorganic fibers, preservatives and insecticides can be added to the papermaking raw material.
[0011]
In the papermaking process S1, pulp (slurry) dispersed in water is spread in a sheet form. The papermaking process S1 can be performed by a known papermaking method. For example, a long net type using a belt-like net, a circular net type using a cylindrical net, or a twin wire type using a pair of endless belt nets can be used. FIG. 2 shows a long net-type paper making apparatus. This apparatus includes a head box 11 capable of supplying slurry at a predetermined flow rate at the rear end (left end in FIG. 2) of the apparatus, and a Ford linear table 13 at the front end of the head box 11. The Ford linear table 13 includes a belt conveyor 15 having an endless conveyor belt formed of a wire mesh material. In order to perform the paper forming process S1 with this apparatus, a slurry paper raw material is put into the head box 11, and the slurry is supplied onto the conveyor belt of the Ford linear table 13 at a predetermined speed. The Ford linear table 13 transports the slurry and drains water from the conveyor belt 21 by gravity to form wet paper obtained by depositing pulp on the conveyor belt. The wet paper obtained in the papermaking process S1 can be continuously sent to the pressing / drying process S3 as it is.
[0012]
The pressing / drying process S3 is a process for removing moisture from the wet paper obtained in the papermaking process S1, and can be a known method used in the papermaking method. The pressing / drying process S3 is generally performed continuously after the papermaking process S1, and the apparatus of the pressing / drying process S3 is followed by the apparatus of the papermaking process S1 as shown in FIG. It can carry out using the well-known paper machine provided.
[0013]
In the pressing, moisture contained in the wet paper is removed within a range that does not break the sheet 53, and pressure is applied to the pulp accumulated by filtration to increase the density. The apparatus shown in FIG. 2 is provided with a pair of press rolls 17 arranged in a plurality of stages on the front end side of the paper making process portion, and a felt (not shown) is provided between the press rolls 17. The pressing presses the felt while sandwiching the wet paper with the press roll 17 to squeeze out the water from the wet paper and compresses the felt with the pressure involved in the pressing. Thereafter, the moisture of the wet paper is sucked using the restoration of the felt when the pressing pressure by the press roll 17 is released.
[0014]
In the drying process, the wet paper is dried by heat to form the paper 42. The drying method is a known method, and a form using a fan dryer that blows hot air may be used, or a form using a cylinder dryer that is dried by contacting the heated drum surface. In the apparatus shown in FIG. 2, the drying process part is arranged on the outer surface of the cylinder 19 and a plurality of cylinders 19 arranged vertically in two stages from the tip of the squeeze process part toward the traveling direction (right direction in FIG. 2). And an endless conveyor belt 21 arranged in close contact with each other. The outer surface of the cylinder 19 is heated to a predetermined temperature. In the drying process, the wet paper after the squeezing process is transported along the conveyor belt 21, so that the wet paper is dried by the heat from the cylinder 19 to obtain the papermaking 42.
In the drying process, it is preferable to reduce the moisture content of the papermaking 42 as much as possible, and at least the moisture content of the papermaking 42 is set to the air-drying moisture content or less. Preferably, when the water content is 5% or less, it is possible to make the impregnation of the binder liquid more uniform throughout the papermaking 42 in a binder application process S5 described later.
[0015]
The property of the papermaking obtained by pressing and drying process S3 is not specifically limited. For example, in the case of manufacturing a desk top plate (a plate material having a good nail holding power), if the paper is made of 3 mm, the binder application process S5 can absorb the thermosetting binder liquid well, and the paper can also be made by dipping. The constituent pulp is preferable because it is difficult to disperse.
[0016]
In the apparatus shown in FIG. 2, as in a known papermaking apparatus, a calendar stack 23 and a reel 25 are provided on the front end side of the drying process portion. With the calendar stack 23, the obtained paper 42 can be further smoothed, and the paper 42 produced in a continuous belt shape can be wound around the reel 25 to form a roll.
[0017]
In the binder application process S <b> 5, the papermaking 42 is immersed in the thermosetting binder liquid 51 to apply the thermosetting binder to the entire papermaking 42. The thermosetting binder liquid 51 is a liquid in which a thermosetting binder component is dissolved or dispersed. As the thermosetting binder, a known binder such as a phenol resin, a urea resin, or a urethane resin can be selected, but it is preferable to use a phenol resin in order to increase the strength of the obtained laminated molded body. The solvent (dispersion medium) of the thermosetting binder liquid 51 is preferably hydrophilic because it is easily absorbed by the papermaking 42. Therefore, when a water-soluble phenol resin is used as the phenol resin, water, a mixed solvent of water and an organic solvent, or the like can be used, which is preferable. Note that water as a solvent is preferable from the viewpoint that the working environment is unlikely to deteriorate unlike the case of using an organic solvent.
[0018]
In the binder application process S5, the papermaking 42 is immersed in a thermosetting binder liquid bath for a predetermined time. FIG. 3 shows an embodiment of a binder application processing apparatus. The apparatus shown in FIG. 3 includes a binder tank 27 that stores a thermosetting binder liquid 51 and a rotating shaft 29 that rotatably holds a roll-shaped paper-making paper 42. The binder tank 27 is provided with a plurality of guide rolls 31 that sandwich and transport the papermaking 42, and a removal roll 33 that sandwiches the papermaking 42 at a position where the papermaking 42 is not immersed in the thermosetting binder liquid 51. ing. In this apparatus, a roll of papermaking 42 is installed on the rotary shaft 29, and the papermaking 42 is fed out with a predetermined rotation, and the papermaking 42 is guided into the binder tank 27 by the guide roll 31. Thereby, the papermaking 42 is immersed in the thermosetting binder liquid 51 stored in the binder tank 27. Thereafter, the papermaking 42 is guided by the removing roll 33 and taken out from the thermosetting binder liquid 51, and the excess thermosetting binder liquid 51 is squeezed out by the removing roll 33. Thereafter, the sheet is further sent to the drying process S7 by a conveying means such as a roll arranged on the leading end side (right side in FIG. 3) from the removing roll 33.
[0019]
The amount of the binder applied to the papermaking 42 can be adjusted mainly by the thermosetting binder concentration. For example, when a paper having a thickness of 3 mm and a water content of 5% is prepared, if a thermosetting binder liquid having a water: water-soluble phenol resin weight ratio of 7: 3 is used, the thermosetting binder is favorably formed into the paper 42. Can be granted.
[0020]
In the drying process S7, the papermaking 42 is dried at a temperature lower than the curing temperature of the thermosetting binder. For example, when a water-soluble phenol resin having a curing temperature of 135 ° C. is used as a binder, it can be reliably dried by being dried at a temperature of 100 ° C. or lower. In the drying at this time, the drying is performed to such an extent that it is possible to prevent the occurrence of rupture or gas bulging due to the generation of water vapor in the subsequent forming step. Specifically, when the water content is 20% or less, it can be molded satisfactorily. Therefore, the drying process S7 may be natural drying at normal temperature or blow drying. When drying process S7 is completed, the papermaking which provided the thermosetting binder can be obtained. The drying apparatus shown in FIG. 3 includes a conveyor 35 that conveys the papermaking 42 that has passed through the removing roll 33, and a fan dryer 37 that is provided so as to surround the conveyor 35. This apparatus dries the papermaking 42 simultaneously with the conveyance. Further, a cutter 38 is disposed at the front end (right end) in FIG. 3, and the paper making 42 is cut into a predetermined size and formed into a layered body 44.
[0021]
(Molding process)
In the molding step 3, as shown in FIG. 4, a desired number of layer bodies 44 are put into a laminated state, and pressed into a desired thickness and shape, and at the same time, the layer bodies are integrated in a laminated state. The molding process 3 includes a heating and pressing process S9 and a cooling process S11. The molding is typically performed using a pair of molds 39 that pressurize by sandwiching a plurality of laminated layers from both sides, as shown in the lower part of FIG.
[0022]
As shown in FIG. 4, at the time of laminating the plurality of layer bodies 44, a sheet may be disposed in a laminated state on at least one surface and heated and pressed simultaneously with the plurality of layer bodies. Thereby, a laminated molded body provided with the sheet 53 on at least one surface can be obtained. The sheet 53 can be provided to give various functions. For example, the design can be applied to the laminated molded body, the surface hardness and the nail holding power can be improved, or the warpage and pulp can be prevented from falling off. It can be provided as a purpose. The sheet 53 applied in this way can be selected from materials that can withstand the heat of the molding step 3. For example, the paper described above can be used as a raw material for waste paper. Further, a resin sheet having a melting point higher than the curing temperature of the thermosetting binder can be used, and for example, a polyester sheet (film) or a polyolefin sheet may be used. In addition, for the purpose of design, a sheet that imparts a texture to the surface, such as a woven fabric, a knitted fabric, or handmade Japanese paper, can be used as appropriate.
The sheet 53 can be appropriately printed in order to impart design properties. The printing can be performed using a known printing technique with a known ink according to the material of the sheet 53. The ink can withstand the heating in the molding step 3. Specifically, oil-based ink can be used.
[0023]
For example, it is preferable to use paper such as drawing paper or titanium paper as a sheet because the nail holding force can be improved. Moreover, these can perform normal printing on paper, and since transparency is small, both nail holding power and designability can be improved.
In addition, you may provide printing directly on the surface of what is arrange | positioned among the layer bodies produced in the layer body formation process 1 at the surface.
[0024]
The heating in the heat and pressure treatment S9 can be performed using a so-called hot press that can set the temperature of the mold surface as desired as the pair of molds 39 described above. In the heat and pressure treatment S <b> 9, heat is transmitted to the inside of the laminated layer body 44, and the thermosetting binder of the entire laminated layer body is cured. For example, in the case where six layered bodies containing the water-soluble phenol resin having a curing temperature of 135 ° C. and having a moisture content of about 20% are stacked, the layer is heated to 150 ° C. and pressurized for about 30 minutes. By the heat and pressure treatment S9, the adjacent layer bodies are bonded to each other by the thermosetting binder and integrated.
[0025]
In the cooling process S11, the compressed state in the heating and pressurizing process S9 is maintained and the cooling is performed to 50 ° C. or lower. In order not to generate a pressure release between the heating and pressurizing process S9 and the cooling process S11, typically, while maintaining the distance between the molds that form a pair pressurized in the heating and pressurizing process S9, That is, the positional relationship shown in the lower part of FIG. 4 is maintained. The cooling process S11 can be performed by canceling the temperature setting of the mold surface of the mold 39 or by leaving it at a desired temperature lower than 50 ° C. The cooling time is, for example, 50 ° C. or less in about 30 minutes by releasing the temperature setting of the mold surface in a layered and integrated layered body (laminated molded body) performed under the conditions of the above-described heating and pressing treatment S9. It is possible to cool down to
[0026]
Here, after the cooling process S11, when the pressure is released by opening the mold 39, the laminated molded body 46 expands slightly. If the expansion rate at this time is large, warping, distortion, and deflection are likely to occur at this point. Therefore, in the cooling treatment S11, in addition to the above temperature conditions, it is preferable to cool so that the expansion rate before and after the pressure release is 0.3% or less in the layered body stacking direction, that is, the thickness direction.
After completion of the cooling process S11, the pressure is released to obtain the laminated molded body 46. Thereafter, the desired product 5 can be obtained by deburring or cutting as appropriate.
[0027]
The laminated molded body 46 obtained by this method is small in deformation such as warping, bending, and distortion, and has high peel strength. That is, by providing the cooling treatment S11 after the heating and pressurizing treatment S9 in the molding step 3, the pressure is released in a state where the thermosetting binder is sufficiently hardened, so that the laminated molded body 46 is not easily deformed by internal stress. Moreover, since the papermaking 42 is immersed in the thermosetting binder liquid 51 and the thermosetting binder is applied to the papermaking 42 after the papermaking 42 is formed, the thermosetting binder is reliably and uniformly applied to the surface of the papermaking 42. be able to. As a result, the heat and pressure treatment S9 can reliably bond the layer bodies 44, and is difficult to peel off. Moreover, even if it is immersed in water, it is hard to peel off, for example, there exists a possibility of using for the washroom and the flooring of a kitchen in which water resistance is required. In particular, the thermosetting binder liquid 51 can be more uniformly permeated into the papermaking 42 by drying the papermaking 42 to a moisture content of 5% or less before the binder application processing S5. Thereby, a deformation | transformation of the laminated molded object 46 can be suppressed favorably. Further, since the permeability of the thermosetting binder liquid 51 is good, the thermosetting binder infiltrates well. Therefore, the strength of the entire laminated molded body 46 can be increased more uniformly, and improvement in strength, rigidity, nail holding power, and the like can be expected.
[0028]
Moreover, in the said manufacturing method, the material containing a plastic etc. can be used as a pulp. Therefore, it is expected that the laminated molded body 46 obtained by the present production method can be used as a raw material for papermaking in the present production method by pulverizing and regenerating pulp. In addition, the phenol resin content in the laminated molded body 46 produced by the above-described method is, for example, about 3%, and when this is pulped, it is considered that a raw material composed of 70% by weight or more is obtained. .
Furthermore, the laminated molded body 46 provided with at least one surface of the sheet 53 becomes a functional molded body provided with a desired function by the sheet 53.
[0029]
Needless to say, the present invention is not limited to the above embodiment.
For example, the paper making process 42 may be performed in a series of steps from the binder applying process S5 to the drying process S7 without forming a roll. Alternatively, the binder application processing S5 and the subsequent steps may be performed after the papermaking 42 is cut into a predetermined size.
[0030]
【The invention's effect】
In the present invention, it is possible to obtain a laminated molded body that can be used satisfactorily in a wider range of applications by providing a method for producing a laminated molded body using pulp while suppressing deformability.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a method for producing a laminated molded body according to the present invention.
FIG. 2 is a plan view showing an embodiment of an apparatus for performing a series of operations from a papermaking process to a pressing / drying process.
FIG. 3 is a plan view showing an embodiment of an apparatus for performing a binder application process.
FIG. 4 is a plan view showing a molding process.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Layer body formation process 3 Molding process 5 Product 11 Head box 13 Ford linear table 15 Belt conveyor 17 Press roll 19 Cylinder 21 Conveyor belt 23 Calendar stack 25 Reel 27 Binder tank 29 Rotating shaft 31 Guide roll 33 Removal roll 35 Conveyor 37 Fan dryer 38 Cutter 39 Mold 42 Papermaking 44 Layer body 46 Laminated molded body 51 Thermosetting binder liquid 53 Sheet S1 Papermaking process S3 Squeezing / drying process S5 Binder application process S7 Drying process S9 Heating and pressing process S11 Cooling process

Claims (3)

A paper making containing 70% by weight or more of fibers derived from natural fibers is immersed in a thermosetting binder solution,
Remove moisture by pressing and drying the paper,
Giving a binder to immerse the papermaking in a thermosetting binder liquid,
Drying the paper at a temperature lower than the curing temperature of the thermosetting binder,
After laminating the desired number of papers, the desired number of laminates are integrated by heating and pressing at a temperature equal to or higher than the curing temperature of the thermosetting binder,
A method for producing a laminated molded body, wherein the integrated laminated body is pressurized to maintain a compressed state, and cooled to a temperature at which the expansion coefficient of the laminated body is 2% or less when the compressed state is released.   The method for producing a laminated molded body according to claim 1, wherein the integrated laminated body is pressurized to maintain a compressed state and cooled to 50 ° C or lower.   The method for producing a laminated molded article according to claim 1 or 2, wherein papermaking having a moisture content of 5% or less is immersed in a thermosetting binder solution.

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