JP3313697B2 - Method and apparatus for direct sheet molding of compound of resin and 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 and an apparatus for directly forming a compound of resin and wood flour, and more particularly to a method of feeding wood from a hopper on the upstream side of a cylinder and supplying wood powder on a screw side feeder on the downstream side. In addition to supplying undried fine wood powder from the hopper, a new venting cylinder is provided immediately after this screw-type side feeder to degas gas and moisture, enabling new sheet forming directly from the sheet die. Regarding improvement.

[0002]

2. Description of the Related Art Conventionally, a method for forming a wood flour sheet using a resin and wood flour compound of this type has been disclosed in Japanese Patent Application Laid-Open No. Hei 10-244534 shown in FIG. JP-A-10-166 shown in FIG.
The configuration disclosed in Japanese Patent Publication No. 355/355 can be mentioned.
That is, what is indicated by reference numeral 1 in FIG. 7 is a cylinder of a meshing type twin screw type kneading extruder 2, and a screw type side feeder having a vacuum evacuation rear belt 3 and a material supply hopper 5 on the upstream side of the cylinder 1. 4 are provided. On the downstream side of the cylinder 1, a pair of vacuum vents 6, 7 and a strand die 8 are provided.

Next, the operation will be described. First, a resin molding material and wood powder containing moisture or moisture are supplied to the material supply hopper 5 of the screw type side feeder 4,
The mixture is kneaded and conveyed downstream in the cylinder 1 by a twin screw. The gas generated during the melt-kneading in the cylinder 1 is discharged out of the cylinder 1 by the rear vent 3 and the vacuum vents 6 and 7. Thereafter, the mixture was extruded into a strand shape by a strand die 8 and processed into compound pellets containing wood flour, and a sheet was formed from the pellets.

Next, in the case of another conventional example shown in FIG.
7 is different from the conventional example of FIG. 7 in that a rear vent 3 is provided on the upstream side of the cylinder 1 of the meshing type twin screw type kneading extruder 2.
And a resin supply hopper 10, and a kneading section 9 is provided between each of the vacuum evacuation vents 6 and 7 on the downstream side of the cylinder 1. The other parts are the same as those in FIG. The same reference numerals are given and the description thereof will be omitted.

Next, the operation will be described. First, 30 to 60 W% of the thermoplastic resin is supplied and melted from the resin supply hopper 10, and 40 to 70 W% of wood powder having a water content of 5 W% or less is supplied from the screw side feeder 4. In the cylinder, the thermoplastic resin and the wood powder are melted and kneaded in a kneading section 9, and the volatile components such as water and wood acid from the wood powder are evacuated and removed from the rear vent 3 and the vents 6 and 7.
The strand was extruded from the strand die 8 into a strand shape, processed and pelletized, and the pellet was used to form a sheet.

[0006]

The conventional method for directly forming a sheet of a compound of resin and wood flour has the following problems because it is constituted as described above. That is, in the case of the conventional configuration shown in FIG. 7, if the wood powder is fine, a large amount of entrained air is generated. There are drawbacks such as not appearing. Also, if the wood powder is fine, the wood powder blows through the rear vent, which is different from the specified wood powder supply amount. If the wood powder is fine, the resin and the wood powder do not adhere well due to batch feed, which is disadvantageous for kneading. Further, the product is not completely drained, and when the sheet is directly formed, the sheet foams, resulting in poor quality. In addition, in the case of the conventional configuration of FIG. In addition, if the sheet is formed directly, the pressurization zone is small and venting up occurs. In addition, if the wood flour is fine, the wood flour would blow out from the rear vent, which would be different from the specified wood flour supply amount.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. In particular, a resin is supplied from an upstream hopper of a cylinder, and a resin is supplied from a wood powder supply hopper on a downstream side of a screw type feeder. By supplying dry fine wood flour and degassing gas and moisture by installing a degas cylinder immediately after this screw side feeder,
It is an object of the present invention to provide a method and an apparatus for directly forming a compound of resin and wood flour, which enable a sheet to be formed directly from a sheet die.

[0008]

According to the present invention, there is provided a method for directly forming a sheet of a compound of resin and wood flour, wherein the resin is supplied from an upstream hopper of a cylinder having a screw and is semi-molten in a first kneading section. In response to the above, the undried fine powdered wood powder supplied from the wood powder supply hopper of the screw type side feeder on the side of the cylinder is supplied, and gas and moisture are removed by the gas release cylinder provided immediately after the screw type side feeder. Kneading in a second kneading section located downstream of the degassing cylinder, deaeration by a vent downstream of the second kneading section, and extruding the molten resin by a sheet die provided at a tip of the cylinder to directly feed the sheet. And a method using one open vent and three vacuum vents connected in series as the vent. The degassing cylinder comprises an upper degassing port and a lower degassing port, and is a method of degassing gas and moisture from the upper degassing port and the lower degassing port. A method of suppressing heat generation at the tip of the cylinder by sending the molten resin to the sheet die through a gear pump provided between the tip of the cylinder die and the sheet die. The compound direct sheet forming apparatus includes an upstream hopper provided upstream of a cylinder having a screw, a first kneading unit provided upstream of the cylinder, and a tree provided downstream of the first kneading unit. A screw-type side feeder having a powder supply hopper, a gas vent cylinder provided immediately after the screw-type side feeder, and a gas vent cylinder provided downstream of the gas vent cylinder A kneading unit and a vent, and a sheet die provided at the end of the cylinder, supplying resin from the upstream hopper, supplying undried fine powder wood powder from the wood powder supply hopper, and And a vent formed from one open vent and three evacuation vents connected in series with each other, and the degas cylinder has an upper deaeration port. And a lower deaeration port, and the bearing provided in the cylinder has a configuration in which a screw tip of the screw penetrates and protrudes into a die hole of a seat die. And a gear pump is provided between the front end portion and the sheet die.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method and an apparatus for directly forming a compound of resin and wood flour according to the present invention will be described below with reference to the drawings. The same or equivalent parts as those in the related art will be described with the same reference numerals. 1 is a cylinder of a meshing type twin screw kneading extruder 2 which is provided with an upstream hopper 10 for supplying a thermoplastic resin upstream of the cylinder 1. The first kneading section 20 provided downstream of the upstream hopper 10 is provided with a screw-type side feeder 4 having a wood powder supply hopper 5 attached to the side of the cylinder 1.

Immediately after the screw side feeder 4 of the cylinder 1, there is provided a gas release cylinder 21 for degassing gas and moisture, and a second kneading provided downstream of the gas release cylinder 21. On the downstream side of the part 22, one open vent 23 and three vacuum evacuation vents 6, 7, 7a are arranged in series with each other. Further, a sheet die 8 for forming a sheet containing wood flour is provided at the tip of the cylinder 1. The vent 100 is configured by the above-described vents 23, 6, 7, and 7a.

The degas cylinder 21 is constructed as shown in FIG. 2 or FIG. That is, in the case of FIG. 2, degassing 30 and 31 are provided on both sides of the cylinder 1, and the degassing 30 and 31 are formed with upper degassing ports 30a and 31a and lower degassing ports 30b and 31b. The upper deaeration ports 30a and 31a and the lower deaeration ports 30b and 31b are configured so that gas and moisture can be deaerated. FIG. 3 shows another embodiment of FIG. 2, in which degassing 30 and 31 are provided on both sides of the cylinder 1, and upper degassing ports 30a and 31a are lower than in the case of FIG. It has a smaller diameter than the deaeration ports 30b and 31b.

As shown in FIGS. 4 and 5, the sheet die 8 is provided at the tip of the cylinder 1 and a bearing 36 provided on a breaker plate 35 provided at the tip of the cylinder 1 is provided inside the cylinder 1. The screw tip 37a of the screw 37 penetrates, and the screw tip 37a faces the die hole 8a of the sheet die 8. Accordingly, the molten resin extruded by each screw 37 in the cylinder 1 is supplied to the bearing 36 of the breaker plate 35.
The screw tip 37a serves as a guide and is supplied into the die hole 8a through the periphery of the screw. The guide of the screw tip 37a prevents the pulsating flow and stagnation of the molten resin into the die hole 8a. It is configured so that the burning phenomenon can be prevented and a uniform molten resin flow can be obtained.

Next, the operation will be described. First, when a resin raw material is supplied from the upstream hopper 10, the resin raw material is not completely melted in the first kneading section 20 because of a short distance, and is in a semi-molten state. The undried fine powdered wood powder supplied from the wood powder supply hopper 5 is supplied into the semi-molten resin by the screw type side feeder 4, and the undried fine powdered wood powder and the semi-molten resin are kneaded. The gas and moisture generated by this kneading state are effectively removed through the upper deaeration ports 30a, 31a and the lower deaeration ports 30b, 31b of the degas cylinder 21, and are further melted and kneaded in the second kneading section 22. Is done.

The resin containing wood flour kneaded in the second kneading section 22 includes an open vent 23, each vacuum vent 6,
After sufficient degassing at 7, 7a, a pulsating flow is generated in the die hole 8a of the sheet die 8 through the periphery of the bearing 36 of the breaker plate 35 and the periphery of each screw tip 37a as described above. It is supplied as a uniform molten resin flow, and is discharged in a sheet form from the discharge port 8aA of the die hole 8a.

In the above-mentioned molding step, since the semi-melted resin and the undried fine powdered wood powder are mixed, the mixing and sticking of the wood powder and the resin are performed very well, and the scattering of the wood powder and the like are performed. Prevention and transportation are also facilitated. In addition, since gas is released by the gas release cylinder 21 before returning to the screw-type side feeder 4, a feedneck phenomenon and a decrease in discharge capacity can be prevented. In addition, since the cylinder 21 uses a slit smaller than the average particle diameter of the wood flour, the wood flour does not escape together with the gas, and the open vent 23 prevents blow-through after kneading. . In addition, one open vent 23
The use of the three vacuum evacuation vents 6, 7, 7a achieves sufficient removal of gas and moisture and prevents poor quality due to foaming of the sheet when the sheet is formed. Although not shown, the step-up capability is increased by inserting a lead 0.75 into the tip of the screw 37.

Embodiment L / D 42, screw diameter 69 mm, four vents including an open vent, and one vent cylinder are provided.
Using a direct sheet forming apparatus having an interlocking twin-screw kneading extruder as shown in FIG. 1 having a sheet die at the tip, the resin is 50% MI18 polypropylene (PP) pellets and the average particle size is 10% water content. 61.3μ diameter
m and 30% talc were formed into a sheet as described above. The results are as shown in Table 1 of Table 1. Wood flour can be up to 50%.

[0017]

[Table 1]

As a comparative example, the results obtained by using the conventional apparatus shown in FIG. 7 and mixing MI18 PP pellets at 50% and a water content of 5% or less and wood powder of an average particle diameter of 61.3 μm at 50% are shown in Table 1. As shown in Table 2 of Table 2, the side feeder became a feeder neck and became inoperable.

[0019]

[Table 2]

As another form of FIG. 1, as shown in FIG. 6, a gear pump 200 is provided at the tip 1A of the cylinder 1, and the seat die 8 is provided at an outlet side of the gear pump 200. ing. The same parts as those in FIG. 1 described above are denoted by the same reference numerals, and description thereof will be omitted. Further, the molten resin from the tip 1A side of the cylinder 1 in FIG. 1 described above is sent to the sheet die 8 via the gear pump 200. In this case, the molten resin from the distal end portion 1A side of the cylinder 1 is sent to the gear pump 200, and the pressure of the molten resin at the distal end portion 1A of the cylinder 1 is, as an example, 19 in the case where there is no gear pump in FIG.
1, 2, and 1,6 Mpa as compared to 2,19.8 Mpa, and the heat generation at the front end 1A can be significantly reduced as compared with the case of FIG. Can be suppressed more effectively.

Examples The results of the examples in which the sheet was directly formed in the above-described case without the gear pump in FIG. 1 and in the case with the gear pump in FIG. 6 will be described. First, in the case of the configuration of FIG. 6, L / D 45.5, screw diameter 69 mm, four vents including an open vent, two degassing cylinders, a gear pump at the tip of the extruder, and a sheet die at the tip Uses a direct sheet forming device equipped with an interlocking twin-screw kneading extruder. The resin is made of wood powder 50 having an average particle size of about 50 μm with a water content of 7 to 8% based on 50% of polypropylene (PP) pellets having a melt index of 17.
The mixture was supplied at a blending ratio of wt%, and was formed into a sheet by the same process as in the embodiment of FIG. 6 described above. The results are shown in Table 3 below.

[0022]

[Table 3]

In the case of the structure shown in FIG. 1, a polypropylene (PP) pellet 50 having a melt index of 17 is used.
%, And a water content of 7 to 8% was supplied at a blending ratio of wood powder of 50 wt% with an average particle size of about 50 μm, and formed into a sheet by the same process as in the embodiment of FIG. The results are shown in Table 4 in Table 4 below.

[0024]

[Table 4]

[0025]

The method and apparatus for directly forming a compound of resin and wood flour according to the present invention are configured as described above, and the following effects can be obtained. That is, since the undried fine wood powder is mixed with the semi-molten resin, the mixing state is improved, the gas and moisture are removed by a degas cylinder, and after kneading, deaeration is performed by four vents. Completely performed and extremely high quality resin and wood flour compound is obtained, so it can be directly formed into sheets by sheet dies without pelletizing as in the past, achieving significant cost reduction and quality improvement. can do. Furthermore, since the pressure of the molten resin is reduced via a gear pump provided at the tip of the cylinder,
Heat generation at the tip of the cylinder can be prevented, and burning of the molded sheet and shark skin can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an apparatus to which a method for directly forming a compound of resin and wood flour according to the present invention is applied.

FIG. 2 is an enlarged configuration diagram of a main part of FIG. 1;

FIG. 3 is a configuration diagram showing another embodiment of FIG. 2;

FIG. 4 is an enlarged plan sectional view showing the sheet die of FIG. 1;

FIG. 5 is a side sectional view of FIG. 4;

FIG. 6 is a configuration diagram showing another embodiment of FIG. 1;

FIG. 7 is a configuration diagram showing a conventional extruder.

FIG. 8 is a configuration diagram showing another embodiment of a conventional extruder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 1A Tip part 4 Screw side feeder 5 Wood powder supply hopper 6, 7, 7a Vacuum vent 8 Sheet die 8a Dice hole 10 Upstream side hopper 20 First kneading part 21 Gas release cylinder 22 Second kneading part 23 Open vent 30a, 31a Upper deaeration port 30b, 31b Lower deaeration port 35 Breaker plate 36 Bearing 37 Screw 200 Gear pump

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 47/00-47/96 B29B ⁷ /00-7/94

Claims (9)

(57) [Claims] A semi-molten resin which is supplied from an upstream hopper (10) of a cylinder (1) having a screw (37) and is semi-molten in a first kneading section (20) is supplied to the cylinder (1). Screw type side feeder (4) on the side of) Wood powder supply hopper
The virgin fine wood powder supplied from (5) is supplied, and gas and moisture are removed by a gas removal cylinder (21) provided immediately after the screw type side feeder (4).
Kneading in a second kneading section (22) located downstream of (21), deaeration by a vent (100) downstream of the second kneading section (22), and a molten resin to the tip of the cylinder (1) A method for directly molding a compound of resin and wood flour, wherein the sheet is directly molded by extruding with a provided sheet die (8). 2. An open vent (23) and three vacuum vents (6, 7, 7a) connected in series with each other as said vent (100). Resin and wood flour compound direct sheet molding method. 3. The degas cylinder (21) has an upper deaeration port.
(30a, 31a) and a lower deaeration port (30b, 31b) for degassing gas and moisture from the upper deaeration port (30a, 31a) and the lower deaeration port (30b, 31b). Claim 1 characterized by the following:
Or a compound direct sheet molding method of resin and wood flour according to 2. 4. By feeding the molten resin to the sheet die (8) through a gear pump (200) provided between the tip of the cylinder (1) and the sheet die (8), the cylinder (1) 4. The method according to claim 1, wherein heat generation at the front end is suppressed. 5. An upstream hopper (10) provided upstream of a cylinder (1) having a screw (37);
A first kneading section (20) provided on the upstream side of (1);
A screw-type side feeder (4) having a wood flour supply hopper (5) provided downstream of the kneading unit (20), and a degassing cylinder (21) provided immediately after the screw-type side feeder (4). A second kneading section (22) and a vent (100) provided downstream of the degas cylinder (21);
A sheet die (8) provided at the tip of (1), supplies resin from the upstream hopper (10), and supplies undried fine powder wood powder from the wood powder supply hopper (5). A resin and wood flour compound direct sheet forming apparatus, wherein a sheet is formed directly from the sheet die (8). 6. The vent according to claim 5, wherein the vent comprises one open vent and three vacuum vents connected in series with each other. Resin and wood flour compound direct sheet molding equipment. 7. The degassing cylinder (21) has an upper deaeration port.
7. The resin and wood flour compound direct sheet molding apparatus according to claim 5, wherein the apparatus comprises a resin (30a, 31a) and a lower deaeration port (30b, 31b). 8. A bearing (36) provided on the cylinder (1).
The screw tip (37a) of the screw (37) penetrates and projects into a die hole (8a) of a sheet die (8). Resin and wood flour compound direct sheet molding equipment. 9. The resin and wood flour according to claim 5, wherein a gear pump (200) is provided between a tip of the cylinder (1) and a sheet die (8). Compound direct sheet forming equipment.