JPS5912808A - Material and method for cleaning thermoplastic resin molding machine - Google Patents

Abstract

PURPOSE:To obtain a cleaning material made from natural fiber mixed thermoplastic resin, having low viscosity and fluidity of the same level as that of fluidity of the conventional cleaner and easy to clean the material staying in a molten resin passage such as a cylinder, nozzle, etc. CONSTITUTION:The titled material prepared by mixing 20-500wt. parts of one kind or more of natural fiber such as wood flour, paper, coconut shell, straw, etc. with 100 wt. parts of thermoplastic resin such as polypropylene, polyethylene vinyl acetate, polyethylene, ABS resin, AES resin, AS resin, etc. After the prescribed thermoplastic resin material is molded by a thermoplastic resin molding machine, the above-mentioned cleaning material is circulated in a molten resin passage of the molding machine to wash the residual resin in the passage. Since the cleaning material is provided with a low viscosity and fluidity of the same level as that of the fluidity of acryl cleaning material, a continuous supply and a short time cleaning are possible. This cleaning material can be extruded by a small quantity of the 2nd material.

Description

[Detailed description of the invention] “The present invention is based on one thermoplastic resin molding machine.

The present invention relates to a material and a cleaning method for cleaning the material that remains in the molten resin passage inside the cylinder, inside the nozzle, etc. when changing the color or material for molding.

Traditionally, two thermoplastic molding machines are used to produce thermoplastic F.
NQI? The inside of the cylinder and nozzle of the molding machine is a good place to change the color of the material or change the material for molding.

It is necessary to discharge the first material accumulated in the molten passageway of the corridor to the outside and replace it.
To discharge the remaining material due to the initial distribution of the second material, or to remove the first material with an acrylic cleaning material (such as crushed scraps of acrylic resin molded products) Thai Clean [product name]. Hereinafter, it will be referred to as cleaning material C. ), and then the cleaning material is discharged and replaced by a second material.

By the way, according to experimental results, as shown in Fig. 1, when a general thermoplastic resin melts and flows through a pipe having a predetermined inner diameter φD, the flow velocity distribution (hereinafter referred to as velocity distribution) V exhibits a so-called non-Newtonian flow in which the flow velocity rapidly decreases from the center of the tube toward the tube wall.

Therefore, according to the former method described above.

@ As shown in Figure 2-a, the material A (thermoplastic resin molded and has a velocity distribution VA [non-Newtonian flow] in the pipe) of the remaining chiku1 is transferred to the second material B (thermoplastic resin material). However, in order to suppress the non-Newtonian flow properties of both materials A and B, as shown in Figure 2-b, .

Since only a very small amount of the first material AFi remaining on the pipe wall is discharged, it is necessary to circulate a large amount of the material B of the phlegm 2 for a long time, resulting in a large amount of work time and a large amount of wasteful consumption of the material B. There was a problem.

In addition, in the latter method, when the cleaning material C is passed through the molten fat passage where the heating has been temporarily interrupted, it becomes a semi-molten solid stream, so its flowability is *2. As shown in Fig.-0, the flow velocity in the pipe is a so-called plug flow in which the velocity distribution VC is almost the same.

Therefore, the first material A is smoothly discharged by the cleaning material C. However, since the cleaning material C is almost a solid flow, it places a high load on the molding machine and cannot be continuously charged, so it has to be fed intermittently. Moreover, the cleaning material C is replaced by the second material B.
Since the cleaning material C has a relatively high viscosity when being extruded, a relatively large amount of the material B is required to discharge the cleaning material C by the initial flow of the material B through the nine rods 2.

The present invention has been made in view of the points mentioned in Section 11.

It is an object of the present invention to provide a cleaning material that has a low viscosity and has flowability equivalent to that of a nuclear cleaning material in place of the acrylic cleaning material C mentioned above, and a cleaning method using the same.

That is, 1 the present invention is based on polypropylene, ethylene vinyl
Lua heptatate, polyethylene, polystyrene, AR8 [
For 100 parts by weight of a thermoplastic resin such as resin, AES resin, and As ferro resin, 9 parts of wood powder and paper and Yasuhiro.

20 to 5 pieces of at least one type of gar, straw, etc. at #1mM
Cleaning materials used for thermoplastic resin molding made by mixing within the range of 0.00 heavy weaving parts, and polypropylene, ethylene vinyl acetate, polyethylene, ? This is a method for cleaning a thermoplastic resin molding machine, characterized in that a cleaning material mixed in a part of the molding machine is passed through a resin passage of the molding machine to wash and discharge the accumulated resin.

Next, specific examples of the present invention will be described.

The powder is produced by charging 100 parts by weight of the powder into a mixer, pulverizing it and dry-mixing it, then melt-mixing it at a temperature of 200''C using a twin-screw extruder, and extruding it into pellets.

Next, a cleaning method using the cleaning material described above will be explained.

First, in order to mold a brown polypropylene resin molded product,
Cheek-shaped polypropylene resin (brown) material (below 9
The first molding material E) is processed using a screw in-line extrusion molding machine (screw cylinder inner diameter:
65-, cylinder length: 1430 m, screw rotation speed near 0 rpm), and the temperature was 211.
Heat and melt 17 at 0″C to inside the screw cylinder 12
．． By circulating the inside of the nozzle 13 (hereinafter referred to as 9 passages 12.13) and pushing the spring into the gap between the pair of molds 14.15 set, depending on the input end of the molding material E,
A predetermined number of brown polypropylene resin molded products are molded. After the molding is completed, as shown in FIG. 4, the pair of molds 14 and 15 are separated and the molded product is taken out. At this time, the first molding material E remains throughout the passage 12.13.

Next, the cleaning material of the present invention described above (hereinafter referred to as cleaning material G) will be described.
Pellet material 3 Kq (called ) is put into the hopper 11, heated and melted at a temperature of 200'C, and passed through the passage 12 in 4 minutes.
13, the molding material staying in the passage 12.13 is discharged to the outside of the molding machine and the passage 12.1
Wash 3. Cleaning material G is replaced in passage 12.1.
It will stay at 3.

In this case, the flowability of the molding material E retained in the 9 passages 12.13 is a non-Newtonian flow with a velocity (9) distribution VB shown in Figure 3-a, and -! Ta. Cleaning material G.

Since the fiber material is dispersed and mixed between the polypropylene particles, when melting and flowing, the friction between the fiber material and the polypropylene particles and between the fiber material particles and the inner wall surface of the pipe is tJ7I.
#! Since it is extremely small, its flowability becomes a plug flow with a velocity distribution of VG. Therefore, the cleaning material G is passed through the passage 12.13.
By feeding and circulating the cleaning material G, the entire passage 12, 13 is smoothly replaced with cleaning material G in a short time.

Next, pellet-shaped polypropylene (gray color) different in color from the molding material E (polypropylene (brown))
Materials (hereinafter referred to as second molding materials F) 4 to 9 are charged into a hopper, melted at a temperature of 200'CC, and circulated through the passages at a temperature of 60°C to remove the cleaning material that remains in the passages 12 and 13. G is discharged to the outside of the molding machine, and im path 12.13
The molding material F is replaced inside.

In this case, the flowability of the molding material F at $2 is a non-Newtonian flow with a velocity distribution VF shown in the diagram @6, and the flowability of the cleaning material G staying in one passage is a plug flow as described above. V
G, the passage is relatively smoothly replaced with the molding material F of the rod 2.

In this way, the color change from brown polypropylene molding to gray polypropylene molding is completed.

Next, after setting the pair of separate molds 14 and 15, the required amount of the molding material F is again put into the hopper 11, and molding of a gray polypropylene molded product is started.

Table 1 shows the amount of cleaning material used, the amount of wasteful consumption of molding material, and the replacement time in the above-described embodiment of the present invention in comparison with the conventional example.

In Table @1, conventional example (1) shows the case where no cleaning material was used, and (2) shows the case where "Tie Clean" (trade name manufactured by Taiho Kogyo ■) was used as the cleaning material.

The molding materials used in Conventional Examples (1) and (2) were exactly the same as those used in the Examples of the present invention. As is clear from Table 1, the use of cleaning materials is almost the same between the iFi wood invention and the conventional example, but the wasteful consumption of molding materials is reduced to about 15q/6 in the present invention, and the cleaning The material replacement time is 20'J compared to the present invention+ compared to the conventional method! 11 □□

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the velocity distribution when a general thermoplastic resin is heated and melted and passed through a circular tube. 2nd] - The figure shows the first molding material staying in the pipe, □2cQ', and 7□, E. . Figure 2-b, a cross-sectional view similar to the @1 river showing the 4th grade cloth, shows the cleaning state inside the pipe when a somewhat different amount of the second molding material is passed from the state shown in Figure 2-8. Figure @2-e is a cross-sectional view similar to the one in which the conventional cleaning material is discharged, and Figure 3-bP3! FIG. 4 is a cross-sectional view similar to that shown in FIG. E...@1 molding material, F...2nd molding material. G...Cleaning material, VE, VF, VG...Velocity distribution of each of molding material E, molding material F, and cleaning material G,
, 11---Hopper, 12... Inside the screw cylinder, 13... Inside the nozzle, 14.15...
...A pair of molds. Patent Applicant Figure 1 Figure 2-<Circle, -2 (8) No. 320 No. 2-km IIIL3
・L diagram @+ diagram l

Claims (2)

[Claims] (1) Polypropylene, ethylene vinyl acetate, polyethylene, polystyrene, ABC@fat. A cleaning material used in a thermoplastic resin molding machine characterized by being mixed in a vacuum. (2) Predetermined thermoplasticity f! by a thermoplastic resin molding machine.
After molding with III material, poly-20□e
Len, ethylene vinyl acetate□, poly□ethylene, pristyrene, AB8 resin, AE8 lump□l! A method for cleaning a thermoplastic resin molding machine, characterized in that cleaning material A is passed through a molten resin passage of the molding machine to clean residual resin in the passage.