JPH0760847A - Open fiber molded form and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve a mechanical strength and buffer properties by adding moisture to a mixture of seed piece made of sheet piece of fiber lump and open fiber, agitating the mixture to entangle the seed piece with the open fiber to form many balls, mixing the balls with paste, and heating to mold it. CONSTITUTION:A mixture of cottonlike open fiber 1 with seed piece 2 of sheet piece or fiber lump is used as a material of a molded form. The fiber 1 is obtained by open fiber of a pin mill structure of old sheet such as newspaper, corrugated fiberboard, etc. As the sheet piece, small pieces of the old sheet remaining in the open fiber in a fiber opening step can be used as it is. As the fiber lump, a matter obtained by collapsing a lump of cellulose fiber to be discharged in the case of papermaking is used. Moisture is added to the mixture of the fiber 1 and the piece 2 and agitated. Thus, the piece 2 is entangled with the fiber 1 to form balls. Paste such as starch, etc., is mixed with the balls. This is casted in molds, heated at 80-120 deg.C, paste is pasted, and dried.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded product obtained by hardening defibrated fibers obtained by defibrating used paper and the like, and a method for producing the same.

[0002]

2. Description of the Related Art A molded product obtained by solidifying defibrated fibers is used as a cushioning material, and a conventional method for producing such a molded product is to form defibrated fibers dispersed in a large amount of water. There are a method of putting in a mold and dehydrating and drying, and a method of mixing glue with dry defibrated fibers and putting it in a molding mold.

[0003]

However, according to the former method, it is difficult to manufacture a product having a thick wall and a high cushioning property. Further, since a large amount of water must be removed during molding, there are problems that dimensional stability is poor and energy cost is high.

On the other hand, according to the latter method, it is possible to obtain a thick and soft molded article having a high cushioning property, but since the defibrated fibers in a dry state are fluffy and bulky, they are packed in a molding die. It is difficult, and when the defibrated fiber is pushed into the mold, it tends to form a layer in the pushing direction. A molded product of defibrated fibers compacted in layers has a problem that it is easily broken in the layer direction and has poor mechanical strength.

Therefore, according to the present invention, a molded product of defibrated fibers which is easy to be packed in a molding die at the time of molding, has good dimensional stability of the molded product, has high cushioning property, and has high mechanical strength is obtained. It is intended to provide a method.

[0006]

Means for Solving the Problems In order to solve the above problems, means taken by the present invention are as follows.

First, a mixture of cotton-like defibrated fibers and paper pieces or seed pieces of fiber lumps is used as a material for the molded body.
The cotton-like defibrated fiber is obtained by defibrating used paper such as newspapers and corrugated board with a defibrating machine having a pin mill structure. As the paper piece, a small piece of waste paper that remains in the defibrated fiber in the defibration process can be used as it is. Further, as the fiber lumps, crushed cellulose fiber lumps discharged during paper making can be used.

As the size of the seed piece, it is preferable that the longest part such as one side or diagonal line has a length of 4 to 10 mm. If it deviates significantly from these ranges, it will be difficult to form beads of defibrated fibers described below.

Next, water is added to the mixture of the cotton-like defibrated fibers and the seed pieces and the mixture is stirred. As a result, a ball is formed in which the seed pieces and the cotton-like defibrated fibers are entangled and collected. FIG. 1 shows a row of balls thus formed. In FIG. 1, reference numeral 1 indicates a defibrated fiber, and 2 indicates a seed piece. The amount of water added here is 50 to 2 in terms of absolute dry weight ratio of the mixture.
50%. When it is 50% or less, the mixture is dry, the seed pieces and the defibrated fibers are less likely to be entangled with each other, and balls are less likely to be formed. On the other hand, when the content is 250% or more, the mixture becomes sticky and the entanglement of the fibers between the balls becomes poor, resulting in insufficient strength of the molded product and deterioration of the buffering property. In addition, it is preferable that the water is added in the form of a mist by sprinkling it on the mixture.

Next, the paste is mixed with the large number of balls formed as described above. As the sizing agent, starch, polyvinyl alcohol, etc. can be used, and the starch is preferably raw starch powder which has no viscosity even when mixed with water. Also,
In terms of price, starch such as potato and corn is preferable. The mixing ratio of this paste is 8 to 50% in absolute dry weight ratio with respect to the above balls. It should be noted that the addition of the paste has the advantage that it can be easily added uniformly if a powdery or granular material is used.

Thereafter, a large number of balls mixed with starch powder are packed in a mold and heated at a temperature of 80 to 120 ° C. to gelatinize the paste. As a heating method, steam heating or microwave heating can be used. In the case of steam heating, if a ventilation hole is provided in the molding die and steam is passed through one hole and steam is discharged through the other hole, heating can be performed in a short time.

After that, when taken out from the molding die and dried, a large number of balls in which the defibrated fibers and the seed pieces are aggregated are solidified in a granular form and are bonded to each other to obtain one molded body as shown in FIG. To be In FIG. 2, reference numeral 3 indicates a grain in which balls in which defibrated fibers and seed pieces are aggregated are solidified.

In the molded product thus obtained, since a large number of balls which are solidified in a granular form are assembled and bonded, there is no directivity in bonding, stable mechanical strength is obtained, and dimensional stability is obtained. Is also good.

Further, in the molded body, a high-density portion in which the balls in which the defibrated fibers and the seed pieces are aggregated are solidified in a granular form and a low-density portion between the grains are formed. The presence of the low-density portion makes it possible to obtain a particularly high buffering property. The specific gravity when the molded body is used as a cushioning material is 0.1
4 to 0.22 g / cm ³ is preferable.

[0015]

[Examples] After roughly crushing newsprint, a cotton-like defibrated fiber in which a piece of paper remains as a seed piece is prepared by a defibrator having a pin mill structure while spraying water.

A raw material is obtained by mixing seed pieces of paper pieces in the cotton-like defibrated fibers, and the moisture content is 50 at an absolute dry weight ratio.
%, 150%, 250% to spray water,
Samples A, B and C are prepared.

Samples A, B, and C were placed in a container having an upper opening, stirred with a rod-shaped body for about 2 minutes, and the seed pieces and cotton-like defibrated fibers were entangled to collect a large number of balls. To form.

Next, the raw starch powder of potato is uniformly added to a bead of a large number of defibrated fibers prepared from Samples A, B and C while stirring at a dry weight ratio of 30%.

Next, sample A, which was made into a ball as described above,
B and C were packed into a rectangular parallelepiped mold having inner dimensions of 130 mm in the long side, 90 mm in the short side, and 30 mm in height, and B and C in an amount of 39 g in terms of absolute dry weight of each mixture. Heated by microwave.

After heating, the sample was taken out from the mold and naturally dried to obtain a rectangular parallelepiped molded body.

Each of the molded bodies molded as described above is placed on a receiving blade having a left-right interval of 100 mm, and a bending test is carried out in which the central portion is pressed downward, and the maximum load at which each sample breaks is determined. It was measured. The results are shown in Table 1.

As a comparative example, a molded body was prepared by using the same raw materials as in Samples A, B and C, adding water in an amount of 45% and under the other conditions as in Samples A, B and C. .
In the case of this comparative example, no balls were formed even if water was added to the mixture and stirred. Table 1 shows the results of a bending test performed as described above using this comparative example as sample D.

[0023]

[Table 1]

From the results shown in Table 1, it is an embodiment of the present invention in which the seed pieces and the defibrated fibers are entangled into balls before the defibrated fibers are molded so that a granular mass remains in the molded product. Samples A, B, and C are much superior in breaking strength, that is, mechanical strength, to the comparative product of Sample D in which cotton-like defibrated fibers and seed pieces are entangled and solidified without forming balls. confirmed.

Next, in order to measure the buffering performance of each sample, a stress-strain diagram shown in FIG. 3 was prepared in accordance with JISZ-0234, and FIG. 4 was prepared based on this stress-strain diagram.
The buffer coefficient-stress diagram shown in FIG.

From FIG. 3, it can be seen that the sample D starts to be strained with a smaller stress than the others and loses its buffering property at an early point. Also, from FIG. 4, compared to Sample D,
Samples A, B, and C, which are the products of the present invention, have a lower minimum buffering coefficient and are more useful as a buffering material, and can cope with a large stress and have a buffering performance for a wide range of stresses. .

[0027]

As described above, according to the present invention, it is possible to obtain a molded product of defibrated fibers having high mechanical strength and high cushioning property.

Further, since the defibrated fibers are made into balls and packed in the mold, the mold can be packed easily, so that the workability in molding is good and the dimensional stability of the molded product is also good.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a state of a ball in which seed pieces and defibrated fibers are entangled and collected.

FIG. 2 is a perspective view showing an example of a defibrated fiber molding of the present invention.

[Fig. 3] Stress-strain diagram

FIG. 4 Buffer coefficient-stress diagram

[Explanation of symbols]

 1 defibrated fiber 2 kinds piece 3 grains

Claims (3)

[Claims] 1. A mixture of a piece of paper or a piece of fiber lumps and a defibrated fiber is added with water and stirred to entangle the seed piece and the defibrated fiber to form a large number of balls. A method for producing a defibrated fiber molding, which comprises mixing a large number of balls and a paste and heat-molding the mixture. 2. The method for producing a defibrated fiber molding according to claim 1, wherein the water content of the mixture is 50 to 250% in terms of absolute dry weight ratio of the mixture. 3. A defibrated fiber molded body in which a large number of balls formed by entangled a piece of paper or a seed of a fiber lump and defibrated fibers are solidified in a granular form and are bonded to each other.