JP2014115195A - Method for measuring powdered resin content of resin fiber mat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple method for measuring the content of a powder resin blended in a resin fiber mat in a production process of a fiber board using a resin fiber mat comprising fibers and a powder resin.
A method for measuring a powder resin content of a resin fiber mat made of a fiber and a powder resin, wherein the powder resin is extracted by suction while applying vibration to the sampled resin fiber mat. The powder resin content of the resin fiber mat is obtained from the mass of the remaining fiber or the mass of the extracted powder resin.
[Selection] Figure 1

Description

  The present invention relates to a method for measuring a powder resin content of a resin fiber mat.

  Conventionally, fiberboards using natural fibers or the like as raw materials are known. This fiberboard is a fiberboard obtained by using natural fibers obtained from bast portions of plants such as kenaf and jute as raw materials and bonding them with resin.

  Since this fiberboard has a structure in which fibers are entangled with each other, it is excellent in strength properties such as bending strength.

  When the fiberboard is manufactured, a resin fiber mat made of fibers defibrated from natural fibers and an adhesive resin is manufactured, and the resin fiber mat is heated and pressed.

  As a method for producing a resin fiber mat, a non-woven fiber mat is molded and then impregnated with a water-soluble resin to produce a resin fiber mat, or a fiber and powder resin are mixed to directly resin fibers. There is a dry method for manufacturing a mat (see, for example, Patent Document 1).

  Among the above-mentioned methods for producing resin fiber mats, the dry method of directly producing resin fiber mats by mixing a powder resin with fibers is a preferred production method from the standpoint of easy material handling and good material yield. is there.

  However, in the dry method of manufacturing a resin fiber mat by mixing a powdered resin with fibers, the resin fiber mat is used during the production of the resin fiber mat and after the production until the heat-press molding. Has fallen off and spilled, resulting in a problem that the resin content of the fiberboard is not stable.

  Therefore, in order to prevent this, a part of the resin fiber mat is sampled during the production of the resin fiber mat or before heat-pressure molding, and the content of the powder resin with respect to the fiber mat is measured. Yes. As this measuring method, the Soxhlet method is usually used.

  The Soxhlet method is a method in which part of a sampled resin fiber mat is immersed in acetone to extract the powder resin and dried to grasp the content of the powder resin, and the method of accurately measuring the content of the powder resin It is.

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  However, since the Soxhlet method requires a large amount of measuring equipment and takes a long time for measurement, it has been considered unsuitable for grasping the content of the powder resin at the production site. Therefore, the development of a simple method for measuring the content of powder resin at the production site has been eagerly desired.

  The present invention has been made in view of the circumstances as described above, and in the production process of a fiberboard using a resin fiber mat made of fibers and powder resin, the content of the powder resin blended in the resin fiber mat is determined. It is an object to provide a simple method for measurement.

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

  That is, the method for measuring the powder resin content of the resin fiber mat of the present invention is a method for measuring the powder resin content of a resin fiber mat composed of fibers and powder resin, and vibration is applied to the sampled resin fiber mat. The powder resin is extracted by sucking in a state, and the content of the powder resin of the resin fiber mat is obtained from the mass of the remaining fiber or the mass of the extracted powder resin.

  Further, in the method for measuring the powder resin content of the resin fiber mat, the resin fiber mat is placed on a sieve, vibration is applied, and the lower part of the sieve is sucked to extract the powder resin. preferable.

  According to the present invention, since the powder resin is extracted by suction while applying vibration to the sampled resin fiber mat, the content of the blended powder resin can be easily adjusted in the process of manufacturing the resin fiber mat. Can be measured.

It is a schematic perspective view which shows the extraction apparatus of the powder resin for implementing this invention.

  Below, one Embodiment of the manufacturing method of the fiber board using the resin fiber mat which can apply the measuring method of the powder resin content of the resin fiber mat of this invention is described.

  In the fiber board manufacturing process, first, a resin fiber mat made of fibers and powder resin is manufactured, and the resin fiber mat is heated and pressed to manufacture a fiber board.

  As the fiber used for the resin fiber mat, various plant fibers can be used. Mention may be made of fibers collected from the stems or end muscles of hemp plants, wood fibers made from conifers, hardwoods and the like.

  Moreover, the fiber which uses as a raw material agricultural wastes, such as sugarcane, corn, bamboo, and rice, such as the squeezed residue after boiling sugar from sugarcane can also be mentioned. These vegetable fibers can be used alone or in a mixture.

  When fibers composed mainly of hemp plants, for example, fibers of hemp plant fibers of 50% by mass or more are used in the total amount of plant fibers, the strength of fiber strength and good dimensional stability during moisture absorption are utilized. Even when the fiberboard contains moisture, the dimensional change of the fiberboard can be reduced.

  The fiber can be obtained by defibrating a long fiber bundle obtained from the bast portion and cutting it into a predetermined length. The average fiber length of the fibers is preferably 5 to 200 mm. The average fiber diameter of the fibers is preferably 500 μm or less.

  A fiber board having good dimensional stability can be obtained by using fibers having an average fiber length and an average fiber diameter in such a range. Of course, fibers having an average fiber length of less than 5 mm, fibers having an average fiber length exceeding 200 mm, and fibers having an average fiber diameter exceeding 500 μm can also be used.

  The average fiber length is measured using a fiber length distribution measuring machine or the like. The average fiber diameter is measured as an average value obtained by measuring fiber diameters at a plurality of locations from an image of an optical microscope or an electron microscope.

  The powder resin is a binder component that bonds the fibers together in the fiberboard. In the present embodiment, a resin that is solid at room temperature (5 to 35 ° C.) but melts when predetermined heat is applied is used as the powder resin.

  Here, “melting” includes the meaning of softening. Examples of the resin type of the powder resin include thermosetting resins such as urea resin, phenol resin, melamine resin, epoxy resin, urethane resin, and unsaturated polyester resin.

  Moreover, thermoplastic resins, such as a polypropylene resin, a polyethylene resin, a polyethylene terephthalate (PET), a vinyl chloride (PVC) resin, can also be mentioned.

  As the particle size of the powder resin, for example, the average particle size is preferably 200 μm or less, and more preferably 100 μm or less. The powder resin having an average particle size within such a range is more easily melted and has better adhesion to the fiber surface.

  As a result, the fibers can be bonded more effectively, and a fiber board having good strength, dimensional stability, and moisture permeability can be manufactured. The lower limit of the particle diameter of the powder resin is not particularly limited, but in practice, the average particle diameter is 10 μm.

  The average particle diameter can be obtained as a median diameter (d50, volume basis) by cumulative distribution from a measured value of particle size distribution by a laser diffraction / scattering method using a commercially available laser diffraction / scattering particle size distribution measuring apparatus. it can.

  In the manufacturing process of the resin fiber mat, an appropriate method can be used for manufacturing the resin fiber mat from the fiber and the powder resin. For example, the fiber and the powder resin are mixed by the following process to obtain the resin fiber mat. Can be manufactured.

  First, the fibers are transported by a transporting conveyor belt, sequentially dropped downward from the end of the conveyor belt, and uniformly distributed on a forming conveyor belt disposed below the transporting conveyor belt. .

  At the same time, a specific amount of powdered resin is dropped from above the molding conveyor belt and uniformly dispersed on the molding conveyor belt.

  At this time, by rotation of the molding conveyor belt, the fibers on the upper surface of the molding conveyor belt and the powder resin are mixed to produce a resin fiber mat. And the manufactured resin fiber mat is conveyed to the heating-pressing process which is the next process.

  Here, the content of the powder resin in the resin fiber mat to be manufactured can be appropriately set in consideration of the characteristics of the fiber board to be manufactured, but is usually 5 to 40% by mass, preferably 15 to 25% by mass. % Range.

  By setting the content of the powder resin within this range, the strength of the fiberboard and the dimensional stability during moisture absorption can be improved at the same time.

  Next, the resin fiber mat is conveyed to a heating and pressing step, and in the heating and pressing step, a pair of heating and pressing plates are heated and pressed into a plate shape to produce a fiberboard.

  When a thermosetting resin is used in the heating and pressing step, the fiber resin is obtained by melting the powder resin of the resin fiber mat by heating and pressing, impregnating the fiber, and thermosetting in that state. .

  The heating temperature at this time may be a temperature at which the powder resin is melted and thermoset. However, if the heating temperature is too high, the fibers may be carbonized, and thus heating is preferably performed in the range of 120 to 200 ° C.

  Moreover, although a press pressure and a press time can be suitably set according to the conditions of the strength performance of the fiberboard obtained and the dimensional stability at the time of moisture absorption, normally, the press pressure is 1-5 MPa, and the press time is 5-20. The condition for minutes.

  Also, when a thermoplastic resin is used as the powder resin used for the resin fiber mat, the fiber is melted and impregnated into the fiber, followed by cold heating and pressing at a temperature at which the powder resin is cured. A board is obtained.

  The press pressure and press time at this time can be appropriately set according to the strength performance of the fiberboard obtained and the dimensional stability conditions during moisture absorption. Usually, the press pressure is 1 to 5 MPa, and the press time is 10 to 10. The condition is for 60 minutes.

Moreover, it is preferable to make it the density of the fiberboard shape | molded to be 0.6-0.9 g / cm < ³ >.

  In addition, when a thermoplastic resin is used as the powder resin, the thermoplastic resin can be easily recovered by heating and melting when the fiberboard is discarded, so that the waste can be easily reused. Can do.

  As mentioned above, although one Embodiment of the manufacturing method of the fiber board using a resin fiber mat was demonstrated, the measuring method of the powder resin content of the resin fiber mat of this invention is during manufacture of the resin fiber mat in the said manufacturing process. It is performed by sampling appropriately, or after the manufacturing process of the resin fiber mat and before the heating and pressing process.

  During the resin fiber mat manufacturing process or before the heating and pressurizing process, the powder resin may fall off the resin fiber mat during conveyance of the resin fiber mat by the conveyor or during storage of the resin fiber mat.

  And when a fiber board is manufactured using the resin fiber mat from which the powder resin has fallen off, there are cases where the specified fiber strength and dimensional stability cannot be obtained.

  Therefore, the powder resin content in the resin fiber mat is measured by using the method for measuring the powder resin content of the resin fiber mat of the present invention, and it is confirmed whether or not the specified amount of the powder resin is contained.

  Hereinafter, the measurement method of the powder resin content of the resin fiber mat of the present invention will be described in detail.

  First, the resin fiber mat immediately before being introduced into the heating and pressing step is sampled. Then, after measuring the mass of the sampled resin fiber mat, vibration is applied to separate the powder resin and the fiber of the resin fiber mat.

  In the present invention, the method for applying vibration to the sampled resin fiber mat is not particularly limited, but vibration can be applied efficiently by using a vibrator or the like.

  And in the state which applied the said vibration, only the powder resin isolate | separated from the fiber is attracted | sucked and powder resin is extracted. Any suction device that can reliably recover the powder resin can be used without particular limitation.

  When the extraction of the powder resin is completed, the mass of the fiber alone or the mass of the extracted powder resin is measured, and the content of the powder resin in the resin fiber mat sampled from the measured mass is calculated. The content of the powder resin can be calculated by the following calculation formula (1) or calculation formula (2).

  If the content (mass%) of the powder resin calculated by the above formula is compared with a predetermined content range, and if it is within the specified range during the production of the resin fiber mat, the supply amount of fiber or powder resin The production of the resin fiber mat is continued without changing, and if it is out of the range, the supply amount of the fiber or the powder resin is adjusted.

  Also, if the resin fiber mat is within the specified range after the resin fiber mat manufacturing process and before the heating and pressurizing step, the lot of the resin fiber mat can be used. A resin fiber mat is used.

  As an apparatus for efficiently carrying out the method for measuring the content of the powder resin of the resin fiber mat according to the present invention, the powder resin extraction apparatus 1 shown in FIG. 1 can be exemplified.

  A powder resin extraction apparatus 1 shown in FIG. 1 includes a sieve 2 and a suction unit 3 for sucking the powder resin provided in the lower part of the sieve 2.

  The opening of the sieve 2 can be appropriately set according to the length of the fiber used for the resin fiber mat 4 to be sampled and the particle diameter of the powder resin, but normally a sieve having a size of 50 to 250 μm is preferably used. Can do.

  When using the powder resin extraction device 1, the sample resin fiber mat 4 is placed on the top of the sieve 2, and the suction resin 3 is used to apply the powder resin to the sieve 2 with vibration applied by a vibrator (not shown). Suction.

  Thereby, it becomes possible to efficiently separate and extract only the powder resin from the resin fiber mat 4.

  As described above, the method for measuring the content of the powder resin of the resin fiber mat of the present invention is very simple, does not select a measurement place, and does not take a measurement time. Can be measured.

  Also, by using the resin fiber mat confirmed by the method for measuring the powder resin content of the resin fiber mat of the present invention, it can be confirmed that a predetermined amount of the powder resin is uniformly dispersed in the resin fiber mat, It is possible to reliably obtain a homogeneous fiberboard without uneven density.

  In addition, since a uniform fiberboard without density unevenness can be obtained, there is no reduction in partial strength, and a fiberboard having excellent peel strength and excellent dimensional stability during moisture absorption can be obtained. it can.

DESCRIPTION OF SYMBOLS 1 Extraction apparatus of powder resin 2 Sieve 3 Suction part 4 Resin fiber mat

Claims (2)

  A method for measuring a powder resin content of a resin fiber mat made of a fiber and a powder resin, wherein the powder resin is extracted by sucking in a state where vibration is applied to the sampled resin fiber mat, and the remaining fibers The powder resin content of the resin fiber mat is determined from the mass of the resin fiber or the mass of the extracted powder resin. 2. The resin fiber mat of claim 1, wherein the resin fiber mat is applied with vibration in a state where the resin fiber mat is placed on a sieve, and the powder resin is extracted by sucking a lower part of the sieve. How to measure quantity.