JP3154953B2 - Method for producing compound pellets containing wood flour - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing compound pellets containing wood powder, in which wood powder is kneaded and dispersed in a resin molding material.

[0002]

2. Description of the Related Art In order to recycle waste wood and section wood as part of resource saving and environmental pollution prevention measures, waste wood and section wood are pulverized and the obtained moisture-absorbing wood powder or wood powder containing moisture is dried. Thereafter, the mixture is blended with a resin molding material by a high-speed blender to form a granular resin compound material containing wood powder, and various molded articles are formed from the resin compound material containing wood powder.

[0003]

However, according to the above-mentioned conventional technique, after a waste wood or a piece of wood is pulverized, moisture-absorbing wood flour or wood flour containing moisture is dried using a drier or the like, and then dried with a high-speed blender. Must be blended with the resin molding material. For this reason, there has been a problem that equipment costs are increased and productivity is low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and can omit the step of drying moisture-absorbing wood flour or wood flour containing water, and can provide compound pellets containing wood flour. It is an object of the present invention to realize a method for producing a compound pellet containing wood flour, which can continuously produce the compound pellets.

[0005]

In order to achieve the above object, the present invention provides a method for producing compound pellets containing wood flour, comprising: a screw-type kneading extruder having an inlet on the side of a heating cylinder; A screw-type side feeder connected to the inlet, a rear vent port provided upstream of the inlet in the heating cylinder, and a pellet manufacturing apparatus provided with a vent port downstream of the inlet; A resin molding material and wood powder containing moisture or wood powder containing moisture are supplied to a type side feeder, introduced into the screw-type kneading extruder from the inlet, and gas generated during melt-kneading by the screw-type kneading extruder is supplied. The mixture is melted and kneaded while vacuum-sucked from the rear vent port and the vent port and discharged to the outside of the machine. It is characterized in that the cutting bets.

It is preferable that the screw-type kneading extruder is a meshing twin-screw kneading extruder.

[0007]

The resin molding material and the wood powder containing moisture or moisture supplied to the screw-type side feeder are kneaded to some extent while being conveyed to the screw-type kneading extruder and introduced into the screw-type kneading extruder. Is done. The resin molding material and moisture-absorbing wood powder or wood powder containing moisture introduced into the screw-type kneading extruder are melt-kneaded by heat transfer from the heating cylinder and shearing heat. The gas composed of the components is released outside the machine by vacuum suction from the rear vent port and the veront port provided on the upstream side and the downstream side of the inlet, respectively. For this reason, a sudden change in pressure due to the gas in the screw-type kneading extruder is suppressed, and stable extrusion is possible.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to an example in which a pellet manufacturing apparatus shown in FIGS. 1 and 2 is used.

The two screws 3 arranged in the heating cylinder 2 of the meshing type twin screw kneading extruder 1
a and 3b are rotated in the same or opposite directions by the rotation drive mechanism 4, and the heating means 13 causes the rear deaeration zone A on the upstream side of the inlet 5 provided on the side surface of the heating cylinder 2 and the inlet 5 side. The solid transport zone B, the kneading zone C, the degassing zone D, and the pressurizing zone E, which are sequentially provided on the downstream side of the heating zone, are heated to different temperatures set in advance.

Further, two screws 22a and 22b arranged in a cylinder 21 of a meshing type twin screw type side feeder 20 having a discharge side communicating with the introduction port 5 are driven in the same direction by a side feeder rotation drive mechanism 24. Or rotate in the opposite direction.

After the above, a resin molding material and wood powder containing moisture-absorbing wood powder or moisture are supplied at a predetermined rate from a supply port 23 provided in a cylinder 21 into a meshing type twin-screw side feeder 20.

The supply of the resin molding material and the moisture-absorbing wood powder or wood powder containing water can be changed so as to be quantitatively supplied to the supply port 23 by using a raw material supply feeder (not shown).

The resin molding material and the wood powder containing moisture or the moisture-supplied wood powder supplied into the intermeshing type twin screw type side feeder 20 are conveyed to the intermeshing type twin screw type kneading extruder 1. After being kneaded to some extent, the mixture is introduced into the solid transport zone B of the heating cylinder 2 through the introduction port 5.

The resin molding material and the wood powder containing moisture or the wood powder containing moisture introduced into the solid transport zone B of the heating cylinder 2 as described above are converted into two rotating screws 3.
a and 3b, the mixture is kneaded while being conveyed from the solid transport zone B to the kneading zone C. At this time, some of the moisture and volatile components evaporate into a gas.
Is vacuum-suctioned by a vacuum pump 8 connected to a rear vent port 6a provided in a rear degassing zone A through a vent pipe 7, and is discharged outside the machine.

After the above, the resin molding material and the wood powder containing moisture or the wood powder containing water conveyed to the kneading zone C are subjected to heat transfer from the heating cylinder 2 and shear heat generated by the two rotating screws 3 a and 3 b. The mixture is melt-kneaded and transported to the degassing zone D.

After the above, the melt-kneaded resin molding material and the wood powder containing moisture or the wood powder containing moisture conveyed to the degassing zone D are conveyed to the pressurizing zone E,
The gas consisting of the remaining moisture and volatile components generated from them is connected to the vent port 6b provided on the upstream side of the degassing zone D and the vent port 6c provided on the downstream side via the vent pipe 7, respectively. Vacuum is drawn by the vacuum pump 8 and discharged outside the machine.

After the above, the melt-kneaded resin molding material and the wood powder from which the moisture has been removed are further uniformly dispersed in the pressurizing zone E, and then are fed into the cutting device 10 as strands from the plurality of nozzles 9 a of the die 9. After being extruded and cut into pellets of a predetermined length by the cutter 11 rotated by the cutter rotation drive mechanism 12, the pellets are discharged out of the machine through the discharge port 10a.

In the present invention, a single-screw kneading extruder may be used in place of the above-mentioned intermeshing twin-screw kneading extruder 1. In addition, a single-screw side feeder may be used instead of the meshing twin-screw side feeder 20.

[0019]

【Example】

Example 1 An interlocking twin-screw kneading extruder having the same configuration as that shown in FIGS. 1 and 2 and having three vents including an L / D 42, a screw diameter of 69 mm, and a rear vent. Machine (made by Japan Steel Works, trade name "T
EX65α-42AW-3V ”), and 50% by weight of moisture-absorbing wood powder having a moisture content of 3% by weight was added to 50% by weight of polypropylene (PP) pellets having a melt index of 1.8 as a resin molding material. The polypropylene-wood flour compound pellets were produced by the same process as in the above-described embodiment, supplied at a weight percentage.

Example 2 Moisture-absorbing wood flour has a moisture content of 1
A polypropylene-wood flour compound pellet was prepared in the same manner as in Example 1 except that it was 0% by weight.

Example 3 Moisture-absorbing wood flour has a moisture content of 2
A polypropylene-wood flour compound pellet was prepared in the same manner as in Example 1 except that it was 0% by weight.

Example 4 Moisture-absorbing wood flour has a moisture content of 3
A polypropylene-wood flour compound pellet was prepared in the same manner as in Example 1 except that it was 0% by weight.

Comparative Example 1 Polypropylene-wood flour compound pellets were produced under the same conditions as in Example 2 except that the rear vent port was closed (no rear vent port was provided).

(Comparative Example 2) An inlet was provided on the upper surface of the heating cylinder of the meshing type twin screw type kneading extruder (the meshing type twin screw type side feeder was not provided). A polypropylene-wood flour compound pellet was produced under the same conditions as in Example 2 except that the powder was charged.

Table 1 shows the evaluation results of Examples 1 to 4 and Comparative Examples 1 and 2.

[0026]

[Table 1]

[0027]

Since the present invention is configured as described above, the following effects can be obtained.

It is not necessary to dry the moisture-absorbing wood flour or wood flour containing water in advance, and the compound pellets containing the wood flour can be manufactured continuously, so that the productivity is remarkably improved.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an example of a pellet manufacturing apparatus provided with a screw-type kneading extruder used for carrying out the present invention.

FIG. 2 is a schematic plan view showing a main part of the pellet manufacturing apparatus shown in FIG. 1 in a partial cross section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intermeshing type twin screw type kneading extruder 2 Heating cylinder 3a, 3b, 22a, 22b Screw 4 Rotation drive mechanism 5 Inlet 6a Rear vent 6b, 6c Vent 7 Vent line 8 Vacuum pump 9 Die 9a Nozzle 10 Cutting device DESCRIPTION OF SYMBOLS 11 Cutter 12 Cutter rotation drive mechanism 20 Meshing type twin-screw side feeder 21 Cylinder 23 Supply port

Continuation of front page (56) References JP-A-10-166355 (JP, A) JP-A-10-235636 (JP, A) JP-A-51-109085 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) B29B 9/00-9/16 B29B ^7/ 00-7/94

Claims (2)

(57) [Claims] 1. A screw-type kneading extruder having an inlet on a side surface of a heating cylinder, and a screw-type side feeder having a discharge side communicating with the inlet, and a rear vent is provided upstream of the inlet in the heating cylinder. Using a pellet manufacturing apparatus provided with a vent and a vent port on the downstream side of the introduction port, supplying a resin molding material and wood powder containing moisture-absorbing wood powder or moisture to the screw-type side feeder, and supplying the wood powder containing the moisture from the introduction port. After being introduced into a screw-type kneading extruder, the gas generated during melt-kneading by the screw-type kneading extruder is melt-kneaded while being vacuum-evacuated from the rear vent port and the vent port and discharged outside the machine, and then into a strand. A method for producing compound pellets containing wood flour, comprising extruding and cutting into pellets. 2. The method according to claim 1, wherein the screw-type kneading extruder is a meshing twin-screw kneading-extruder.