JP2016196162A - Method for producing fiber board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a fiber board having excellent bending strength, excellent peeling strength, and an excellent hygroscopic expansion coefficient of thickness and also excellent nail holding force.SOLUTION: A method for producing a fiber board includes heating and pressure molding of a fiber mat formed from plant fiber. In the method, the plant fiber is mixed with saccharides and then acids to form a fiber mat, and the formed fiber mat is subjected to heating and pressure molding.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a fiber board.

  Fiber boards such as medium density fiberboard (MDF) are widely used as materials for housing equipment and the like. These are made from the waste materials used in sawmill, low-quality chips not used for papermaking, and plant fibers obtained from building demolition materials. It is a gentle material. In addition, it has characteristics such as stable quality, less anisotropy and good workability compared to a sawing board obtained by sawing wood.

  Thermosetting resin adhesives such as urea resin adhesives, melamine resin adhesives, phenol resin adhesives and the like are usually used as adhesives used for manufacturing these fiber boards. These adhesives are derived from petroleum and formaldehyde is used as a curing agent. Moreover, these are required to be aqueous in order to suppress the diffusion of the organic solvent.

  However, in recent years, such petroleum-based adhesives have a problem of formaldehyde emission, and although reduction measures have been taken, formaldehyde emission cannot be completely suppressed. On the other hand, petroleum-based isocyanate-based adhesives that do not disperse formaldehyde have been developed, but their reaction with moisture, bonding with metals, and the like have been issues and are not widely used.

  Under such circumstances, considering the emission of formaldehyde and the like, use of a composition derived from a plant-derived material and a polycarboxylic acid as main components has been studied. However, it is difficult to say that the fiberboard molded using this adhesive satisfies the physical properties such as bending strength, peel strength, water absorption thickness expansion coefficient, etc., and it takes a long molding time to achieve physical properties that can withstand practical use. It was necessary to optimize the heating time and ingredients.

  In addition, an adhesive containing a Maillard reaction product of an amine such as an ammonium salt of a polycarboxylic acid and a carbohydrate such as a saccharide has been studied, but this is due to a Maillard reaction of an amine and a saccharide, and is inexpensive. The polycarboxylic acid cannot be used as it is.

  In such a situation, a cheaper polyvalent carboxylic acid is used, and a fiber mat is formed by mixing an adhesive composition having high adhesiveness using saccharides and polyvalent carboxylic acid and plant fibers. A method of manufacturing a fiber board in which the fiber mat is heated and pressed is proposed (see, for example, Patent Document 1).

JP 2014-51568 A

  The fiber board described in Patent Document 1 is considered to be excellent in that it has physical properties such as excellent bending strength, peel strength, water absorption thickness expansion coefficient, and the like.

  This is because the saccharide mixed simultaneously with the polyvalent carboxylic acid reacts and functions as an adhesive to firmly bond the plant fibers to form a fiber mat.

  However, in the proposal described in Patent Document 1, a part of the blended polyvalent carboxylic acid degrades plant fibers by decomposing saccharide components (mainly hemicellulose) in plant fibers in addition to the saccharides blended at the same time. There was a case. And in the characteristic of the fiber board heat-press-molded using the fiber mat containing the deteriorated vegetable fiber, the fall of a nail holding power may be caused, and there was still room for improvement about this point.

  The present invention solves the above problems and provides a method for producing a fiber board having excellent bending strength, peel strength, water absorption thickness expansion coefficient, and excellent nail holding power. Let it be an issue.

  The present invention is characterized by the following in order to solve the above problems.

  A method of manufacturing a fiber board in which a fiber mat formed from plant fibers is heated and pressure-molded, wherein the plant fiber is mixed with sugar, then mixed with an acid, and then formed into a fiber mat, and the formed fiber mat is heated. It is characterized by pressure molding.

  The present invention also relates to a method for producing a fiber board in which a fiber mat formed from plant fibers is heated and pressed, after mixing an alkaline component or a polysaccharide with the plant fibers, and then mixing a saccharide and an acid. A fiber mat is formed, and the formed fiber mat is heated and pressed.

  ADVANTAGE OF THE INVENTION According to this invention, while having the outstanding bending strength, peeling strength, and a water absorption thickness expansion rate, the manufacturing method of the fiber board which has the outstanding nail holding power is provided.

It is a flowchart which shows the manufacturing process of one Embodiment (1st Embodiment) of the manufacturing method of the fiber board of this invention. It is a flowchart which shows the manufacturing process of other embodiment (2nd Embodiment) of the manufacturing method of the fiber board of this invention.

  Hereinafter, the manufacturing method of the fiber board of this invention is demonstrated in detail, giving the form (1st Embodiment and 2nd Embodiment) for inventing.

  The manufacturing method of the fiber board of 1st Embodiment mixes saccharides with a vegetable fiber, then mixes an acid, forms a fiber mat, and heat-press-molds the formed fiber mat.

  In the manufacturing method of the fiber board of the first embodiment, first, saccharides are sufficiently adhered to the surface of the plant fibers in advance by mixing the saccharides with the plant fibers to obtain a mixture. The acid is then mixed with the mixture to prevent direct contact of the acid with the surface of the plant fiber. Thereby, it becomes difficult for the saccharide | sugar component in a plant fiber and an acid to react, and it becomes possible to prevent deterioration of a plant fiber.

  Below, the plant fiber, saccharides, and acid which are used by this 1st Embodiment are demonstrated.

  Examples of plant fibers that can be used include hemp-based natural fibers, palm fibers, agricultural waste fibers, and wood fibers.

  Hemp-based natural fibers are plant fibers made from bast fiber-based plants such as kenaf, jute, flax, ramie, hemp, and sisal. Bast fiber-based plants are already distributed as general industrial raw materials in the spinning and nonwoven fabric industries, and can be stably procured. By mechanically defibrating the fiber bundle obtained from the bast portion of this bast fiber plant, fibers having high strength and excellent dimensional stability can be obtained.

  Further, by appropriately determining the defibrating conditions, the fiber bundle can be defibrated to a predetermined fiber length and fiber diameter, and the target plant fiber can be obtained relatively easily. When obtaining the target hemp natural fiber from the bast fiber plant, for example, it can be obtained according to the following procedure.

  First, a bast fiber bundle having a length of several tens of cm to several m and a width of about 5 mm to 30 mm is collected from the bast portion of the bast fiber plant. Next, the bast fiber bundle is cut so as to have a length of about 5 to 10 cm using a rotary cutter or the like. Next, the bast fiber bundle is defibrated using a lapping machine or the like until the target average fiber length and average fiber diameter are obtained.

  A repelling machine is a machine that has a mechanism in which a cylinder equipped with a pin with a sharp tip and a cutting blade rotates at high speed. By passing the fiber bundle through this anti-wool machine, the bundled fiber bundle is separated. Can be defibrated and fiberized.

  Palm fiber is fiber made from plants such as oil palm and coconut palm. This plant material can also be procured stably. High strength by defibrating the fiber part after squeezing palm oil from the fruit bunches such as oil palm and coconut to the prescribed fiber length and fiber diameter, similar to the bast fiber bundle described above Can be easily obtained.

  Agricultural waste fiber is a fiber made from agricultural waste such as sugar cane, corn, bamboo, and rice. For example, a bagasse fiber having a small bulk density can be obtained by drying a squeezed residue (hereinafter referred to as bagasse) after boiling sugar from sugarcane and then processing it into a fiber. Then, similarly to the bast fiber bundle described above, the target fiber can be easily obtained by defibrating to a predetermined fiber length and fiber diameter. Bagasse has conventionally been discarded or used as boiler fuel, paper raw materials, livestock feed, fertilizer, and the like, but has recently attracted attention as an available biomass resource due to increasing environmental problems.

  In addition to bagasse, the desired agricultural waste fibers can be obtained by defibrating corn, bamboo stalks, rice straw and other raw materials. By using raw materials that have been discarded in the past, waste can be reduced and valuable resources can be saved. In addition, the cost of the fiber board can be reduced.

  Wood fiber is a fiber made from conifers, hardwoods, and the like. The wood fiber can use miscellaneous trees, woodwork scraps, waste materials, defective timbers, thinned wood, etc., which are generally used as MDF raw materials. For this reason, it is possible to effectively use wood-based raw materials that are valuable resources from the viewpoint of the global environment. Similar to the above-mentioned bast fiber bundle, by defibrating such a wood-based raw material to a predetermined fiber length and fiber diameter, the target plant fiber can be easily obtained.

  Among the above plant fibers, hemp-based natural fibers can be preferably used from the viewpoint of further improving the strength and dimensional stability of the fiber board and obtaining the fiber board at a lower cost. In addition, the plant fiber can be used by appropriately combining plant fibers such as hemp-based natural fiber, palm fiber, agricultural waste fiber, and wood fiber.

  The average fiber length and the average fiber diameter of the plant fiber can be appropriately determined according to the use and characteristics of the fiber board to be molded, but the average fiber length is usually 5 to 100 mm, preferably 10 to 70 mm, more preferably. Is in the range of 30-60 mm. Moreover, an average fiber diameter is 70-400 micrometers, Preferably it is 100-350 micrometers, More preferably, it is the range of 150-300 micrometers.

  By setting the average fiber length and the average fiber diameter within these ranges, a fiber board having excellent strength and dimensional stability can be obtained due to the entanglement of plant fibers.

  In addition, an average fiber length can be measured using a fiber length distribution measuring machine etc., and an average fiber diameter can be measured as an average value which measured the fiber diameter in several places from the image of an optical microscope or an electron microscope.

  Further, it is desirable that the moisture content of the plant fiber is 5% or less, preferably 3% or less. When the moisture content of the plant fiber is higher than 5%, the moisture absorption amount of sugars and acids increases, and the particles tend to aggregate. As a result, the dispersibility with the plant fiber is lowered, and the plane tensile strength is easily lowered. In addition, adjustment of the moisture content of a vegetable fiber can be performed using a vacuum dryer, a thermo-hygrostat, etc.

  As the saccharide, a monosaccharide, disaccharide, oligosaccharide, polysaccharide, or the like can be used.

  Examples of monosaccharides include fructose, ribose, arabinose, rhamnose, xylulose, deoxyribose and the like.

  Examples of the disaccharide include sucrose, maltose, trehalose, tulanose, lactulose, maltulose, palatinose, gentiobiulose, melibiurose, galactosucrose, lutinulose, planteobiose and the like. Examples of the oligosaccharide include fructooligosaccharide, galactooligosaccharide, mannan oligosaccharide, and stachyose. Examples of the polysaccharide include starch, agarose, alginic acid, glucomannan, inulin, chitin, chitosan, hyaluronic acid, glycogen, and cellulose.

  Among these, “saccharides” in the present invention are preferably disaccharides and oligosaccharides. In particular, disaccharide sucrose can be preferably used. Moreover, said sugar may be used individually by 1 type, and may be used in combination of 2 or more type.

  As the acid, a divalent or higher acid (polybasic acid) is preferable, and in particular, a polyvalent carboxylic acid can be suitably used. The polyvalent carboxylic acid can be used without particular limitation as long as it is a compound having a plurality of carboxyl groups, and specific examples thereof include the following.

  Citric acid, tartaric acid, malic acid, succinic acid, oxalic acid, adipic acid, malonic acid, phthalic acid, sebacic acid, maleic acid, fumaric acid, malonic acid, itaconic acid, glutaric acid (1,5-pentanedioic acid), Gluconic acid, glutaconic acid, pentenedioic acid and the like. An anhydride can also be used.

  Among polyvalent carboxylic acids, citric acid, tartaric acid, malic acid, gluconic acid, sebacic acid, itaconic acid and the like are preferable because they are produced from plants, and citric acid is particularly preferable from the viewpoint of availability. Can be used. Moreover, these may be used individually by 1 type and may be used in combination of 2 or more types.

  The mixing ratio of the saccharide and the acid is 10 to 90 parts by mass, preferably 20 to 80 parts by mass, 90 to 10 parts by mass of the acid when the total of the saccharide and the acid is 100 parts by mass. Preferably it is set as the range of 80-20 mass parts.

  By setting the mixing ratio of the saccharide and the acid within the above range, the carboxyl group of the acid contributing to the reaction with the saccharide can be set to an appropriate value, so that it becomes easy to cure and high adhesion between the plant fibers is obtained. be able to.

  The saccharide or acid may be a solution, but at least one of the saccharide or acid is preferably a powder.

  The average particle size of the saccharide in the powder is preferably 25% or less of the average fiber size of the plant fiber. More preferably, it is 10 to 20% of range. By setting the average particle size of the saccharide powder within this range, the surface of the plant fiber can be covered widely, and the contact between the plant fiber and the acid can be reduced. That is, since the reaction between the acid and the saccharide component (mainly hemicellulose) in the plant fiber can be reduced, deterioration of the plant fiber can be suppressed, and a fiber board having excellent nail holding power can be obtained. It becomes possible.

  The average particle diameter when the acid is powdered is not particularly limited, but is usually 30 μm or less, preferably 5 to 20 μm. By setting the average particle size of the acid powder within the above range, when formed on a fiber mat, the acid powder can be uniformly dispersed throughout the fiber mat, and a fiber board having excellent planar tensile strength can be obtained. Can be obtained.

  In addition, the average particle size of the powdered saccharides and the acid of the powder is a cumulative distribution from the measured value of the particle size distribution by the laser diffraction / scattering method using a commercially available laser diffraction / scattering type particle size distribution measuring device. Median diameter (d50, based on volume).

Below, the manufacturing method of the fiber board of 1st Embodiment is demonstrated. FIG. 1 is a flowchart of a first embodiment of a fiber board manufacturing method of the present invention. Hereinafter, it demonstrates in detail along each process of FIG.
(Step S1-1: First Step)
First, a plant fiber that has been defibrated to a predetermined average fiber length and an average fiber diameter and adjusted to a predetermined moisture content is mixed with sugars to obtain a mixture. The blending ratio of the plant fiber and the saccharide can be appropriately determined according to the characteristics of the fiber board to be produced. Usually, the saccharide is 5 to 25 parts by mass, preferably 10 to 20 parts per 100 parts by mass of the plant fiber. It can mix | blend so that it may become the range of a mass part.

  Moreover, when adding the solution of saccharides, it can mix, spraying the solution on a vegetable fiber by spray etc.

Here, in manufacture of a mixture, it can mix with a small cotton blender etc. which add a vegetable fiber and saccharides and has a cylinder with a pin, and can be made into a mixture.
(Step S1-2: Second step)
Next, an acid is added to the mixture obtained in the first step (S1-1), and the mixture is sufficiently mixed so that the acid is uniformly dispersed in the mixture. This mixing can be performed using a small cotton blender or the like having a pinned cylinder used in the manufacture of the mixture in the first step.

At this time, both acid and saccharide may be added and mixed. When an acid solution is added, the acid solution can be mixed while sprayed on the plant fiber by spraying or the like.
(Step S1-3: Third step)
Next, the mixture containing the obtained acid is formed into a mat shape to obtain a fiber mat. For example, a device called a mat former that continuously produces fiber mats can be used for forming a fiber mat from a mixture containing an acid. The fiber mat can also be formed by a method such as spraying a mixture containing an acid in a mold.

In addition, when the saccharide solution is added in the first step (step S1-1), and when the acid solution is added in the second step (step S1-2), the formed fiber mat is a dryer or the like. The fiber mat can be made into a B-stage fiber mat by drying to a constant weight.
(Step S1-4: Fourth step)
Next, the formed fiber mat is heated and pressed to form a fiber board. For heating and pressure forming of the fiber mat, for example, a continuous press device that conveys the fiber mat while applying pressure to a gap between a pair of heated steel belts, or heating by placing the fiber mat between a plurality of heated hot plates. A pressurizing multi-stage press apparatus or the like can be used. The molding conditions can be appropriately determined depending on the types of saccharides and acids added and the surface weight of the fiber mat, and are not particularly limited, but are preferably in the range of a temperature of 140 to 230 ° C. and a pressure of about 1 to 5 MPa. . The heating and pressing time can be appropriately determined according to the thickness of the fiber board and the forming temperature.

  In addition, if necessary, a mat heat treatment for heating the fiber mat before heat-pressure molding may be performed to melt and react the saccharide and acid on the surface of the plant fiber in the fiber mat. As a result, the reaction product of the molten saccharide and acid can be uniformly dispersed and held in the void portion of the aggregate in which the plant fibers are intertwined. When handling the fiber mat, such as when the fiber mat is handled, It is possible to suppress detachment and segregation of acid and acid.

  Next, the fiber board obtained after molding can be made into a fiber board by performing post-processing such as adjusting the moisture content (curing) or cutting it into a predetermined size, if necessary.

  According to the fiber board manufacturing method of the first step (step S1-1) to the fourth step (step S1-4), first, in the first step (step S1-1), sugars are added to the surface of the plant fiber. The mixture to which is attached is adjusted. Thereby, even if an acid is added to the mixture in a 2nd process (process S1-2), it becomes possible to reduce a direct contact with a vegetable fiber and an acid. That is, since the reaction between the acid and the saccharide component in the plant fiber can be reduced, deterioration of the plant fiber can be suppressed, and a fiber board having excellent nail holding power can be obtained.

  As a form for implementing this invention, a fiber board can be manufactured by 2nd Embodiment demonstrated below besides the said 1st Embodiment.

  In the fiber board manufacturing method of the second embodiment, plant fibers and alkaline components or polysaccharides are mixed to form a mixture, and then the mixture is mixed with sugars and acids to form a fiber mat. Heat-press molding is performed.

  In the fiber board manufacturing method according to the second embodiment, first, plant fibers and an alkaline component or polysaccharide as an additive are mixed to form a mixture, and the additive is sufficiently adhered to the surface of the plant fibers in advance. . And the direct contact of an acid is prevented with respect to the surface of a vegetable fiber by mixing saccharides and an acid with respect to this mixture. Thereby, similarly to 1st Embodiment, the saccharide | sugar component in a vegetable fiber and an acid become difficult to react, and it becomes possible to prevent deterioration of a vegetable fiber.

  The plant fiber, saccharide and acid used in the second embodiment can be the same as the plant fiber, saccharide and acid used in the first embodiment.

  The alkaline component is not particularly limited as long as it does not degrade the plant fiber. For example, slaked lime, calcium hydroxide, magnesium hydroxide, and the like can be used.

  As the polysaccharide, generally known polysaccharides can be used, and examples thereof include starch, agarose, alginic acid, glucomannan, inulin, chitin, chitosan, hyaluronic acid, glycogen, and cellulose. Among these, starch can be preferably used.

  Because polysaccharides as additives are relatively weakly reactive with acids, for example, even when strong acids are used to shorten the heating and pressurization time for fiberboard molding, plant fiber degradation is suppressed. And a fiber board having excellent nail holding power.

  The blending ratio of the alkaline component or the polysaccharide is not particularly limited as long as it is a blending ratio that can cover the surface of the plant fiber, and can be appropriately determined depending on the type and amount of the plant fiber. As these compounding ratios, an alkaline component can be normally mix | blended so that it may become the range of 5-30 mass parts with respect to 100 mass parts of plant fibers, Preferably it is 10-20 mass parts. Moreover, a polysaccharide can be mix | blended so that it may become the range of 2-25 mass parts with respect to 100 mass parts of plant fibers, Preferably it is 10-20 mass parts.

  The saccharide, the alkaline component, the polysaccharide, and the acid may be a solution, but at least one of the saccharide, the alkaline component, the polysaccharide, and the acid is preferably a powder.

  When the alkaline component or polysaccharide is used as a powder, the average particle diameter is 25% or less, preferably 10 to 20% of the average fiber diameter of the plant fiber. By setting the average particle size of the alkaline component powder or polysaccharide powder within this range, the entire surface of the plant fiber can be covered, and contact between the plant fiber and the acid can be prevented. That is, since the reaction between the acid and the saccharide in the plant fiber can be prevented, deterioration of the plant fiber can be suppressed, and a fiber board having excellent nail holding power can be obtained.

  In addition, the powder average particle diameter of the alkaline component of the powder or the polysaccharide of the powder, using a commercially available laser diffraction / scattering type particle size distribution measuring device, from the measured value of the particle size distribution by the laser diffraction / scattering method, It can be obtained as a median diameter (d50, volume basis) by cumulative distribution.

Below, the manufacturing method of the fiber board of 2nd Embodiment is demonstrated. FIG. 2 is a flowchart of a second embodiment of the fiber board manufacturing method of the present invention. Hereinafter, it demonstrates in detail along each process of FIG.
(Step S2-1: First Step)
First, a plant fiber adjusted to a predetermined average fiber length and average fiber diameter and adjusted to a predetermined moisture content is mixed with an alkaline component or polysaccharide as an additive to obtain a mixture.

In the production of the mixture, as in the first step (step S1-1) in the first embodiment, plant fibers and alkaline components or polysaccharides are mixed using a small cotton blender having a pinned cylinder. It can be a mixture. Moreover, when adding the solution of an alkaline component or a polysaccharide, it can mix, spraying the solution on a plant fiber by spray etc.
(Step S2-2: Second step)
Next, a saccharide and an acid are added to the mixture obtained in the first step (S2-1), and the mixture is sufficiently mixed so that the saccharide and the acid are uniformly dispersed in the mixture. This mixing can be performed using a small cotton blender or the like having a pinned cylinder used in the manufacture of the mixture in the first step.

  Here, the saccharide and the acid may be added separately, but a saccharide and an acid may be added in advance at a specific mixing ratio to form a binder.

Moreover, when adding the solution of saccharides or an acid, the alkaline component or polysaccharide of a specific mixing | blending ratio can be made into the state of a solution previously, and it can mix, sprinkling that solution on a plant fiber by spray etc.
(Step S2-3: Third step)
Next, the mixture which mix | blended the obtained saccharide | sugar and an acid is formed in mat shape, and it is set as a fiber mat. The fiber mat can be formed by a method similar to the third step (step S1-3) of the first embodiment.

  In addition, when adding the solution of saccharides and an acid in the said 2nd process (process S2-2), the formed fiber mat is dried with a dryer etc. until it becomes constant weight, can do.

  Then, the fiber board is obtained by performing the third step (step S2-3) and the fourth step (step S2-4) in the same manner as in the first embodiment, with respect to the mixture containing the prepared saccharide and acid. Can be manufactured.

  According to the fiber board manufacturing method of the second embodiment described above, first, in the first step (step S2-1), a mixture in which an alkaline component or polysaccharide as an additive is attached to the surface of the plant fiber is prepared. To do. Thereby, even if saccharides and an acid are added to the mixture in a 2nd process (process S2-2), it becomes possible to prevent a direct contact with a vegetable fiber and an acid. That is, as in the first embodiment, since the reaction between the acid and the saccharide in the plant fiber can be prevented, degradation of the plant fiber can be suppressed, and a fiber board having excellent nail holding power is obtained. be able to.

  As mentioned above, although the manufacturing method of the fiber board of this invention was demonstrated based on embodiment, the manufacturing method of the fiber board of this invention is not limited to said embodiment, In the range which does not deviate from the summary, it is various. Can be changed.

  For example, only the acid is added in the second step of the first embodiment, and only the saccharide and the acid are added in the second step of the second embodiment. However, other components such as an inorganic filler, p-toluenesulfonic acid as a reaction accelerator, a colorant, and the like can be added as long as the effects of the present invention are not impaired.

  Moreover, in the 1st process of 1st Embodiment, the alkaline component or polysaccharide as an additive can also be mix | blended with saccharides.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.
Example 1
Using a small blender with a pinned cylinder of jute plant fibers and powder saccharides with an average fiber length of about 10 mm and an average fiber diameter of about 150 μm, so that the plant fibers and powder saccharides are uniform. Mix to make a mixture. Next, powder acid was added to the mixture and further mixed.

The following saccharides and powder acids were used, and the mixing ratios shown in Table 1 were used.
Sugar of powder: Sucrose (manufactured by Wako Pure Chemical Industries, Ltd.) (average particle size of about 20 μm)
Powder acid: citric acid (manufactured by Wako Pure Chemical Industries, Ltd.) (average particle size of about 20 μm)
Next, using a simple forming apparatus (inner dimension of the formwork: 30 cm square), the acid-added mixture was sprayed on the formwork to form a mat, thereby obtaining a fiber mat.

Next, this fiber mat was heat-press molded under the conditions shown in Table 1 using a small hot press machine to obtain a fiber board having a thickness of 4.5 mm and an average density of 750 kg / m ³ . The thickness was adjusted with a spacer.
(Example 2)
The jute plant fiber used in Example 1 and the powdered starch (polysaccharide) were mixed using a small cotton blender having a pinned cylinder so that the plant fiber and the starch starch were uniform. A mixture was obtained. Next, saccharide powder and acid powder were added to the mixture and further mixed. The powdered saccharide and the powdered acid were mixed in advance.

The same powder saccharide and powder acid as in Example 1 were used, and the following starch (polysaccharide) was used. Each blending ratio was set as shown in Table 1.
Powdered polysaccharide: starch (particle size 15-40 μm)
Next, using a simple forming device (inner dimension of the formwork: 30 cm square), the mixture added with sugar and acid was sprayed on the formwork to form a mat, thereby obtaining a fiber mat. Next, this fiber mat was molded under the same conditions as in Example 1 to obtain a fiber board.
Example 3
A fiber board was obtained in the same manner as in Example 2 except that the starch of Example 2 was changed to calcium hydroxide (alkaline component).

The following were used for calcium hydroxide (alkaline component), and the blending ratio was as shown in Table 1.
Alkaline component of powder: Calcium hydroxide (Wako Pure Chemical Industries)
(Comparative Example 1)
The jute plant fiber used in Example 1 and the powdered saccharide and acid were mixed so that the plant fiber and the powdered saccharide and acid were uniform using a small blender having a pinned cylinder. To make a mixture. The powdered saccharide and the powdered acid were mixed in advance.

Next, using a simple forming apparatus (inner dimension of the formwork: 30 cm square), the mixture was sprayed on the formwork to form a mat, thereby obtaining a fiber mat. Next, this fiber mat was molded under the same conditions as in Example 1 to obtain a fiber board.
Example 4
The jute plant fiber used in Example 1 and the powdered saccharide were mixed using a small cotton blender having a pinned cylinder so that the plant fiber and the powdered saccharide were uniformly mixed to obtain a mixture. Next, an aqueous acid solution was added to the mixture by spraying and further mixed.

The same saccharide powder as used in Example 1 was used, and the following aqueous acid solution was used. The blending ratio was set as shown in Table 1.
Acid aqueous solution: citric acid (manufactured by Wako Pure Chemical Industries) (33% aqueous solution)
Next, using a simple forming device (inner size in mold: 30 cm square), a mixture to which an aqueous acid solution was added was sprayed on the mold to form a mat, and then a constant weight was obtained at about 80 ° C. with a dryer. The fiber mat which was dried to become B-stage was obtained. Next, this fiber mat was molded under the same conditions as in Example 1 to obtain a fiber board.
(Example 5)
The jute plant fiber used in Example 1 and the powdered starch (polysaccharide) were mixed using a small cotton blender having a pinned cylinder so that the plant fiber and the starch starch were uniform. A mixture was obtained. Next, an aqueous solution of saccharide and acid was added to the mixture by spraying and further mixed.

The same starch (polysaccharide) as in Example 2 was used, and the following aqueous solutions of sugar and acid were used. Each blending ratio was set as shown in Table 1.
Aqueous solution of saccharide and acid: a mixture of the saccharide and acid of Example 1 to obtain a 33% aqueous solution. Next, a mixture containing the saccharide and acid was formed in the same manner as in Example 4 to form a fiber mat. Obtained. Next, this fiber mat was molded under the same conditions as in Example 1 to obtain a fiber board.
(Example 6)
A fiber board was obtained in the same manner as in Example 5 except that the starch of Example 5 was changed to calcium hydroxide (alkaline component).

In addition, the calcium hydroxide (alkaline component) used the same thing as Example 3, and the thing similar to Example 5 was used for the aqueous solution of saccharides and an acid. Each blending ratio was set as shown in Table 1.
(Comparative Example 2)
Using a small blender having a pinned cylinder for the jute plant fiber used in Example 4 and the aqueous solution of the saccharide and acid used in Example 5, the saccharide and acid of the plant fiber and powder are uniform. So that a mixture was obtained.

Next, this mixture was formed in the same manner as in Example 4 to obtain a fiber mat. Next, this fiber mat was molded under the same conditions as in Example 4 to obtain a fiber board.
(Evaluation)
When the bending strength, peel strength, and water absorption thickness expansion rate of the fiber boards produced in Examples 1 to 6 and Comparative Examples 1 and 2 were measured by the method of JIS A5905, they were almost the same. It was.

And nail reverse drawing resistance was measured by the method of JISA5905, and the following references | standards evaluated. The results are shown in Table 1.
◎: 500N or more ○: 450N or more and less than 500N ×: Less than 450N

  From this result, it was confirmed that the nail reverse drawing resistance of the fiber boards of Examples 1 to 6 is superior to those of Comparative Examples 1 and 2. This is thought to be due to the fact that the degradation of the plant fiber by acid was suppressed.

Moreover, it was confirmed that the bending strength, peel strength, and water absorption thickness expansion rate of the fiber boards of Examples 1 to 6 were excellent as in the case of conventional fiber boards.

Claims (6)

A method for producing a fiber board in which a fiber mat formed from plant fibers is heated and pressed,
A method for producing a fiber board, comprising: mixing a saccharide with the plant fiber; then mixing an acid; then forming a fiber mat; and heating and pressing the formed fiber mat.   The method for producing a fiber board according to claim 1, wherein at least one of the saccharide and the acid is powder. A method for producing a fiber board in which a fiber mat formed from plant fibers is heated and pressed,
A method for producing a fiber board, comprising mixing plant components with an alkaline component or a polysaccharide, then mixing a saccharide and an acid, forming a fiber mat, and then heating and pressing the formed fiber mat.   The method for producing a fiber board according to claim 3, wherein at least one of the saccharide, the alkaline component, the polysaccharide, and the acid is powder.   5. The fiber board manufacturing method according to claim 2, wherein an average particle diameter of the saccharide powder is 25% or less of an average fiber diameter of the plant fiber. The said saccharide is a disaccharide or an oligosaccharide, The manufacturing method of the fiber board as described in any one of Claim 1 to 5 characterized by the above-mentioned.

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