JP4601382B2 - Manufacturing method of fiber molded body - Google Patents

Description

  The present invention relates to a method for producing a fiber molded body.

  As a method for producing a fiber molded body, a wet fiber laminate is made from a fiber slurry by a wet papermaking method, the moisture of the fiber laminate is dehydrated by suction, and the fiber laminate after dehydration is heated to a desired temperature. There is known a method of placing in a dry mold and performing dry molding by press molding.

  By the way, when manufacturing the fiber molded object which has a corner | angular part in such a manufacturing method, there existed a subject which a crack tends to produce intensively in the said corner | angular part and its peripheral part. As a technique for preventing the occurrence of cracks in the method of manufacturing a fiber molded body, a sheet-like or three-dimensional fiber laminate is made from a slurry containing a fiber material, moisture is given to the surface, and then dry-molded with a dry mold. Techniques have been proposed (see Patent Documents 1 and 2 below). However, in these techniques, there are many processes such as a process of drying a wet papermaking to make a dry papermaking, a process of adding moisture to the dried papermaking again, and a process of drying it again. There is a problem of poor production efficiency.

JP 57-47999 A JP-A-8-13400

  The present invention has been made in view of the above problems, and can suppress generation of cracks in a fiber molded body during dry molding, and can simplify the process and improve production efficiency as compared with conventional molding methods. It aims at providing the manufacturing method of a fiber molded object.

  The present inventors heated the surface of the fiber laminate where cracks are likely to occur before drying the fiber laminate in a dry mold, and dried the surface to generate cracks after dry molding. As a result, the present invention has been completed.

  The present invention is a method for producing a fiber molded body comprising a papermaking step of making a wet fiber laminate from a fiber slurry containing a fiber material, and a dry molding step of dry-molding the fiber laminate, The object is achieved by providing a method for producing a fiber molded body in which the surface of the fiber laminate is heated and dried before the fiber laminate is dry-molded.

  According to the method for producing a fiber molded body of the present invention, the occurrence of cracks can be prevented and the drying efficiency can be improved, so that the productivity of the product can be increased.

  The present invention will be described below based on preferred embodiments with reference to the drawings.

  FIG. 1 schematically shows an embodiment of a production apparatus used in the method for producing a fiber molded body of the present invention. In FIG. 1, the code | symbol 1 has shown the manufacturing apparatus.

  The manufacturing apparatus 1 manufactures a semi-cylindrical fiber molded body 11 (see FIG. 6), and includes a raw material supply means 2 for supplying a fiber slurry as a raw material, and a fiber slurry supplied from the raw material supply means 2. A paper making means 3 for making a wet fiber laminate, a heating means 4 for heating the made fiber laminate, and a dry forming means 5 for dry-molding the fiber laminate heated by the heating means 4 are provided. Yes.

  The raw material supply means 2 includes an injection pipe 20, a vertical movement mechanism 21 that moves the injection pipe 20 up and down, and a slurry supply pipe 22 that supplies fiber slurry into the injection pipe 20. A valve 23 is provided in the slurry supply pipe 22.

  The papermaking means 3 includes a papermaking mold 30 having a so-called male shape. The papermaking mold 30 has a papermaking portion 301 corresponding to the shape of the fiber laminate to be papermaking. A papermaking net 302 is arranged on the surface of the papermaking part 301. A gas-liquid flow passage (not shown) is provided inside the papermaking unit 301, and a discharge pipe 304 leading to the suction pump 303 is connected to the gas-liquid flow passage. A valve 305 is disposed in the discharge pipe 304.

  In the present embodiment, the heating means 4 includes a dryer 40 that blows hot air on the surface of the woven fiber laminate.

  The dry molding means 5 includes a female mold 50 and a male mold 51. The female die 50 has a concave shaped portion 500 corresponding to the outer shape of the obtained fiber shaped body 11. The female die 50 includes a heater 501 that heats the molding unit 500. The female mold 50 is moved up and down by the vertical movement means 502. The male mold 51 has a convex molded portion 510 corresponding to the inner surface shape of the obtained fiber molded body 11. The molding portion 510 of the male mold 51 is provided with a gas-liquid flow passage (not shown) opened on the surface thereof, and a discharge pipe 512 leading to the suction pump 511 is connected to the gas-liquid flow passage. ing. A valve 513 is disposed in the discharge pipe 512. Although not shown in the drawing, a heater for heating the molding unit 510 is disposed inside the molding unit 510.

  The manufacturing apparatus 1 includes moving means (not shown) that moves the papermaking mold 30 and the male mold 51 to predetermined positions along the guide 60. Further, the manufacturing apparatus 1 includes control means (not shown) including a sequencer that is connected to each of the above-described means and operates each of the means according to a procedure that will be described later.

  Next, the manufacturing method of the fiber molded body of this invention is demonstrated as a preferable embodiment based on the manufacturing method of the fiber molded body using the said manufacturing apparatus 1, referring FIGS. In these drawings, reference numeral 10 denotes a fiber laminate, and 11 denotes a fiber molded body.

  The method for producing a fiber molded body according to the present embodiment includes a paper making process for making a wet fiber laminate from a fiber slurry by a wet paper making method, a preheating process for heating the fiber laminate before dry forming, and the fiber. A dry molding step of dry-molding the laminate.

  In the process of making the fiber laminate, as shown in FIG. 2, the injection pipe 20 is lowered by the vertical movement mechanism 21 so that the papermaking part 301 of the papermaking mold 30 is accommodated in the injection pipe 20, the valve 23 is opened, and the slurry The fiber slurry is supplied into the injection pipe 20 through the supply pipe 22. When the supply amount of the fiber slurry reaches a predetermined amount, the valve 23 is closed, the supply of the fiber slurry is stopped, the valve 305 is opened, and the liquid of the fiber slurry is discharged by the suction pump 303 through the gas-liquid flow passage and the discharge pipe 304. As the component is sucked, the solid component is deposited on the surface of the papermaking net 302 to form the wet fiber laminate 10. The liquid content of the fiber laminate 10 is determined by the handling properties of the fiber laminate 10 and the deformation of the fiber laminate 10 due to the flow of fibers when the fiber laminate 10 is pressed between the female mold 50 and the male mold 51 ( In view of the fact that it is better to be deformed to some extent by pressing), 50 to 200 parts by mass is preferable, and 70 to 100 parts by mass is more preferable with respect to 100 parts by mass of the solid content in the fiber laminate 10. The liquid content can be adjusted by suction of the liquid component through the suction pump 303. As the raw material fiber slurry, one prepared so as to be compatible with the fiber molded body to be produced is used. As the fiber slurry, a known fiber slurry conventionally used in wet papermaking can be used.

  When the paper making of the fiber laminate 10 is completed, as shown in FIG. 3, the injection tube 20 is pulled up by the vertical movement mechanism 21, and the paper making mold 30 is moved along the guide 60 by the moving means of the dryer 40 of the heating means 4. Moved down. In the case of a semi-cylindrical fiber molded body having a cross-sectional diameter and a partially different shape as in this embodiment, the corner portion 110 and its vicinity (see FIG. 6) are easily cracked by the dryer 40. Heated. The liquid content on the surface of the heated portion is preferably 70 parts by mass or less, particularly 10 to 50 parts by mass with respect to 100 parts by mass of the solid content in the fiber laminate, considering the increase in tear strength due to drying. Moreover, the liquid content on the back surface of the heated portion is 50 to 200 parts by mass, particularly 70 to 100 parts per 100 parts by mass of the solid content in the fiber laminate, considering the deformation of the fiber laminate 10 by the press described above. It is preferable to set it as a mass part. In addition, since each liquid content changes the color tone of the surface of the part with the reduction | decrease of the liquid component in a fiber laminated body (for example, it changes from black gray to white gray), the liquid content and color tone of a fiber laminated body beforehand By examining the relationship and observing the color tone of the portion to which hot air is applied, the moisture content of that portion can be determined almost accurately. In the present invention, the entire surface of the fiber laminate may be heated. However, as described above, the occurrence of cracks is also suppressed by heating the portion where cracks are likely to occur. Moreover, by such partial heating, the heating time of the fiber laminate can be shortened, and downsizing of the heating means can also be achieved.

  Next, the fiber laminate 10 that has been heated by the heating means 4 is transferred to the male mold 51. Then, in the subsequent dry forming step, as shown in FIG. 4, the female mold 50 heated to a predetermined temperature is lowered by the vertical movement mechanism 502 and is brought into contact with the male mold 51 heated to the predetermined temperature. The fiber laminate 10 is dry-molded between these male and female molds. At this time, as described above, the temperature reduction of the inner surface of the molding unit 500, that is, the female die 50 is suppressed by heating the fiber laminate, and the drying efficiency of the fiber laminate 10 is not reduced. Dry in time. The temperatures of the female mold 50 and the male mold 51 are appropriately set according to the fiber molded body to be manufactured. However, in consideration of prevention of scorching of the fiber laminate 10, the temperature is preferably 100 to 250 ° C, more preferably 120 to 180 ° C. preferable.

  During dry molding, the valve 513 is open, and the moisture in the fiber laminate 10 is sucked by the suction pump 511 via a gas-liquid flow path and a discharge pipe 512 (not shown) and discharged to the outside. On the other hand, the injection tube 20 is lowered by the vertical movement mechanism 21, the papermaking portion 301 of the papermaking mold 30 is accommodated again in the injection tube 20, and the fiber laminate is newly made in the same manner as in the papermaking step.

  When the dry molding process is completed, as shown in FIG. 5, the female mold 50 is pulled up by the vertical movement mechanism 502, and the fiber molded body 11 remaining on the male mold 51 side is removed from the male mold 51, and the fiber molded body 11 is removed. Manufacturing is complete. Moreover, the injection tube 20 is pulled up by the vertical movement mechanism 21, and the new fiber laminated body which finished the papermaking process is moved to the above-mentioned partial heating process. In the manufacturing method of the present embodiment, such paper making, surface heating, and dry molding steps are repeatedly performed.

  As described above, according to the method for manufacturing a fiber molded body of the present embodiment, the dry-molding is performed after the part that is prone to cracking is partially heated before the dry molding. And can prevent cracking during dry molding. Moreover, since the temperature drop of the female mold 50 and the male mold 51 during dry molding can be suppressed, the drying efficiency of the fiber laminate 10 can be improved, and the productivity of the fiber molded body (product) can be increased. it can.

  The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention.

  Heating of the fiber laminate surface before dry molding is preferably performed using hot air, but microwaves or infrared rays can also be used.

Hereinafter, the present invention will be described more specifically with reference to examples.
<Example>
Raw material blended in a ratio of 24 parts by weight of pulp (new newspaper), 8 parts by weight of inorganic fibers (carbon fibers), 48 parts by weight of inorganic powder (obsidian powder) and 16 parts by weight of organic binder (phenol resin) is dispersed in water and solid A slurry having a partial concentration of about 3% by mass was prepared. Using this slurry, a fiber laminate having the same shape as that of FIG. 6 is made (the thickness of the paper is 1 mm to 3 mm), and further dried with a fluororesin (for example, Teflon (registered trademark)) coating. After this fiber laminate is arranged on the male mold, hot air from the heat gun is applied to the substantially vertical wall surface (surface indicated by A in FIG. 6) of the fiber laminate mainly with a heat gun (maximum outlet temperature 500 ° C.) When the surface of the portion to which is applied is in a dry state (moisture content of less than 20 parts by mass with respect to 100 parts by mass of solids in the fiber laminate), the fiber laminate is covered with a dry female mold and pressed. Was further dried to obtain a fiber molded body. The pressing pressure during drying was 3.8 MPa, and the temperature of the drying mold was 150 ° C. As for the water content, several types of samples having different color tones were dried at 105 ° C. for 1.5 hours, and the color tone and water content were examined in advance from the change in mass before and after drying these samples. And the color tone of the part which applied the hot air of the fiber laminated body was observed, and the moisture content was calculated | required based on the said test result.

<Comparative example>
Fabricate a fiber laminate using the same raw material slurry and paper making method as in the example, and place the fiber laminate on a dry male mold without applying hot air by a heat gun, and immediately cover the dry female mold with the dry female mold. The fiber laminate was press-dried to prepare a fiber molded body. The pressure and temperature during press drying were the same as in the examples.

<Result>
In the examples, tearing, perforation and the like were not confirmed throughout the fiber molded body, and a good fiber molded body was obtained. On the other hand, in the comparative example, tearing and perforation defects occurred in several places on the wall surface of the fiber molded body, particularly on the wall surface substantially perpendicular to the mold opening surface. This is because the vertical wall surface has a small clearance between the male and female molds during clamping, and is subjected to a shearing direction. Although the tear resistance was improved by the hydrogen bonding force, it was a good product. However, the fiber laminate of the comparative example was considered to be a defective product because the surface was not dried to the extent that the tear resistance was improved.

  The fiber molded body manufacturing method of the present invention is suitable for manufacturing various types of fiber molded bodies such as containers, tools, and parts having corners and substantially vertical wall surfaces, including molds having corners and substantially vertical wall surfaces. is there.

It is a fragmentary sectional view which shows typically one Embodiment of the manufacturing apparatus used for the manufacturing method of the fiber molded object of this invention. It is a figure which shows typically the papermaking process in one Embodiment of the manufacturing method of the fiber molded object of this invention. It is a figure which shows typically the partial heating process of the fiber laminated body surface before the dry shaping | molding in one Embodiment of the manufacturing method of the fiber molded object of this invention. It is a figure which shows typically the dry shaping | molding process in one Embodiment of the manufacturing method of the fiber molding of this invention. It is a figure which shows typically the demolding state after completion | finish of the dry forming process in one Embodiment of the manufacturing method of the fiber molded object of this invention. It is a perspective view which shows an example of the fiber molded object manufactured with the manufacturing method of the fiber molded object of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 2 Raw material supply means 3 Papermaking means 30 Papermaking mold 4 Heating means 40 Dryer 5 Dry molding means 50 Female type 51 Male type 10 Fiber laminated body 11 Fiber molded object

Claims (2)

A method for producing a fiber molded body comprising: a paper making step for making a wet fiber laminate from a fiber slurry containing a fiber material; and a dry molding step for dry molding the fiber laminate,
In the paper making process, using a suction pump, the liquid content of the fiber laminate is sucked to 70 to 100 parts by mass with respect to 100 parts by mass of the solid content in the fiber laminate,
Before dry-molding the fiber laminate, the surface of only the portion of the fiber laminate that is prone to cracking is heated, and the liquid content of the heated surface of the portion is 100 parts by mass of the solid content of the fiber laminate. Of the fiber molded body dried to 10 to 50 parts by mass and dried to 70 to 100 parts by mass with respect to 100 parts by mass of the solid content of the fiber laminate . Production method. The manufacturing method of the fiber molded object of Claim 1 which heats the surface of the part in which the said fiber laminated body tends to produce a crack using a hot air, a microwave, or infrared rays.

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