JP3010158B1 - Extrusion molding method for recovered PET bottles - Google Patents

Abstract

Abstract: [Purpose] Extrusion molding of civil engineering supplies, gardening supplies, stationery, daily miscellaneous goods and various molded products such as industrial, domestic pipes, conduits, and thick plates by effectively using the collected PET bottles. I do. The dehumidified pulverized material of a recovered PET bottle is provided.
A composition comprising 1 to 50 parts by weight of a carbon-based material selected from carbon black, charcoal, coal, coke and fly ash and 0 to 100 parts by weight of a dry and crushed igneous rock is supplied to a screw feeding zone: compression zone: The ratio of the measurement zones is (3 to 40): (1): (1 to 15),
A carbon or polytetrafluorocarbon liner is extruded using an extruder provided on the inner surface of an extrusion die and a sizing die, and is taken out by a pressure sizing method by pushing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extruding various molded products using a recovered PET (polyethylene terephthalate resin) bottle.

[0002]

2. Description of the Related Art Regarding reuse of recovered PET bottles,
The methods that have been implemented or promoted in Japan to date are:
Usually, the recovered PET bottles are usually washed with water, purified and returned to the original polyethylene terephthalate (PET) resin, and then formed into fibers, injection molded articles, bottle molded articles, etc. according to the original molding method. Therefore, since the cost is often higher than when virgin PET resin is used, the way of recycling PET bottles, which have consumed 200,000 tons or more per year as of 1998, has hardly been exploited.

[0003] Not only recovered PET bottles, but also P
There is no report on profile extrusion molding of ET resin.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a recovered PET.
It is intended to provide a method for effectively utilizing a large amount of bottles to form various molded articles.

[0005]

SUMMARY OF THE INVENTION The present invention relates to 100 parts by weight of a dehumidified pulverized recovered PET bottle, 1 to 50 parts by weight of a carbonaceous substance selected from carbon black, charcoal, coal, coke and fly ash, and igneous rock. A composition consisting of 0 to 100 parts by weight of the dry pulverized product was added to the extruder at a screw feed zone: compression zone: measurement zone ratio of (3
To 40): (1): (1 to 15), and extruding a liner of carbon or polytetrafluorocarbon using an extruder provided on the inner surface of an extrusion die and a sizing die,
This is a method for extruding a recovered PET bottle, which includes taking over by a pressure sizing method by pushing.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention,
A composition comprising 100 parts by weight of a dehumidified pulverized material of a recovered PET bottle, 1 to 50 parts by weight of a carbon-based material selected from carbon black, charcoal, coal, coke, and fly ash and 0 to 100 parts by weight of a dry pulverized material of igneous rock. Used.

[0007] The recovered PET bottle used in the present invention is one that has been pulverized by a pulverizer and dehumidified. PET is hydrolyzed by its water content at the extrusion molding temperature, and the carboxyl group generated by the hydrolysis acts as an autocatalyst to promote the hydrolysis. Therefore, the pulverized material of the recovered PET bottle is dehumidified to reduce the water content. It is desirable that the content be 300 ppm or less.

In PET bottles, among PET resins which are crystalline polymers, those having a low intrinsic viscosity (IV) of 0.9 or less are often used. PET has a low melt viscosity,
It is difficult to perform extrusion molding as it is.

In the present invention, a carbon-based material is recovered from PE
Since 1 to 50 parts by weight is used with respect to 100 parts by weight of the pulverized material of the T bottle, a stable extrusion molding operation can be performed, and appropriate lubricity can be given to an extruder die and a sizing die, and igneous rock When the pulverized material is used in combination, the wear of the screw or barrel cylinder of the extruder can be prevented by blending the carbon-based material. The carbon-based material is selected from carbon black, charcoal, coal, coke, fly ash at the time of coal-fired power generation, and the like, and two or more kinds may be used in combination.

In the present invention, for example, in order to obtain a product corresponding to a boundary concrete block or the like specified in JIS A5307, a dry pulverized product of igneous rock is added in an amount of 0 to 100 weight per 100 parts by weight of a pulverized product of a recovered PET bottle. Part can be used. As the igneous rock, natural lava such as andesite, basalt, rhyolite, gabbro, granite, pyroclastic rock and the like can be used.

Further, any inorganic substance such as calcium,
Use in combination with carbonates, sulfates, silicates, phosphates, borates, oxides, hydroxides and hydrates thereof such as silicon, magnesium, aluminum, titanium, iron and zinc, silica, bentonite and clay Alternatively, an additive such as a pigment for coloring the block product may be added.

In extruding the composition of the present invention, any extruder having a constant pitch or variable pitch screw, such as a single screw extruder or a multi-screw extruder rotating in the same direction or different directions, is used. be able to. However, PET bottles are of a low grade of intrinsic viscosity (IV) in many cases of 0.9 or less among PET resins which are crystalline polymers, and have a low melt viscosity. It is necessary to use an extruder having a screw basically different from an extruder used for extrusion of an amorphous polymer such as an impact-resistant styrene resin.

The screw of an extruder used for extrusion of an amorphous polymer has a compression zone and a metering zone which are longer than a feed zone, and a feed zone: a compression zone:
The ratio of the metering zones is generally 1: (2-5) :( 2-
However, when PET is extruded with such a screw, a surging phenomenon in which the shape and dimensions of the product fluctuates occurs, and the work is not stable, so that a molded product cannot be obtained. Therefore, in this invention, the screw which made the ratio of a supply zone: a compression zone: a metering zone (3-40) :( 1) :( 1-15) is used. The compression ratio is desirably in the range of 2 to 5. In addition, productivity can be improved by using a multi-die extruder in which a plurality of dies are provided for one extruder.

Further, since the intrinsic viscosity and the melt viscosity of PET are low, it is necessary to provide a liner on the inner surface of both the extrusion die and the sizing die in an extruder to improve the lubricity of the discharged material. It is. As this liner, a polytetrafluoroethylene liner or a carbon-containing polytetrafluoroethylene liner is used in addition to the carbon liner.

By providing these liners on the inner surfaces of both the extrusion molding die and the sizing die, the molded product is smoothly promoted when the PET composition undergoes a phase transition from a molten state to a solid state through a semi-molten state. It becomes possible.

Furthermore, since the melt viscosity of the PET composition is low, it is necessary to impart resistance to the flow of the discharged material when flowing from the extruder molding die to the sizing die in order to improve the physical properties and dimensional accuracy of the product. . Therefore, a pressure sizing take-off method by pushing is adopted. In particular,
By using a speed reducer with torque control, the speed of the take-off roll is automatically controlled to always provide a constant reverse resistance to the propulsion of the molded product. As a result, pressure can be applied inside the sizing die.

When extruding the PET composition of the present invention to produce, for example, a civil engineering block specified in JIS A5307, the PET composition may be molded within a required tolerance range such as a tolerance specified in JIS A5307. Therefore, it is important for the dimensional accuracy and physical properties of the product to make the inside of the molded product as uniform as possible in the sizing die regardless of the size of the cross-sectional area, but the PET composition changes from a molten state to a solid state. Since the temperature range of the resulting phase transition is extremely narrow, it is often difficult to uniformly cool the inside only by cooling from the outside of the product. In that case, if the extrusion molding of the present invention is hollow extrusion molding, the molded article can be cooled not only from the outside but also from the inside,
This is effective for improving extrusion productivity and dimensional stability.

The product manufactured by the extrusion molding of the present invention is an extruded product having various cross sections or a modified extruded product. Not only a solid molded product but also a hollow molded product manufactured by hollow extrusion molding. Can be. Specifically, JIS
A sidewalk boundary block as defined in A5307,
In addition to land boundary blocks, sidewalk pavement flats, park promenade flats, shopping street sidewalks, U-shaped lids and other civil engineering products, horticultural products, stationery, daily goods, industrial and household pipes, It is a conduit or a thick plate.

According to the method of the present invention, it is possible to provide aesthetics, abrasion resistance, and necessary coloring while maintaining specified performance and strength, such as required dimensions, tolerances, and bending strengths. . Therefore, products corresponding to a wide range of blocks and flat plates of civil engineering concrete such as terrazzo tiles and terrazzo blocks can also be manufactured.

[0020]

Next, the present invention will be described based on examples, but the present invention is not limited thereto.

Example 1 A recovered PET bottle bale was finely pulverized using a pulverizer ZA-560 manufactured by Horai Co., Ltd., which was pulverized by a shearing force between a rotary blade and a rotary blade.

The andesite was dried and finely pulverized with a pulverizer manufactured by Tokyo Atomizer Manufacturing Co., Ltd.

The fly ash was dried and manually ground with a millstone.

These three types of pulverized raw materials were
With a mixing ratio of 00 parts by weight, andesite 10 parts by weight, and fly ash 10 parts by weight, a super mixer S manufactured by Kawata Corporation
Mixing, pulverization, and dehumidification were performed using MG300, and the final water content of the composition was adjusted to 210 ppm.

This composition was subjected to JIS A5 using a 115 mm single screw extruder manufactured by Tanabe Plastics Machine Co., Ltd.
A double-sided sidewalk road boundary block A (upper width 150 mm, lower width 190 mm, height 200 mm) specified by 307 was formed into a hollow body by profile extrusion. The hollow portion was circular with a diameter of 80 mm.

The extrusion conditions at that time are as follows.

The ratio of the feed zone of the screw: the compression zone: the metering zone was 7: 1: 5.

On the inner surface of the extrusion die and the sizing die,
A carbon liner having an outer diameter of 335 mm was provided, and the inner surface thereof was shaped like a molded product. The molded article was cooled from the outside by passing water through the outside of the sizing die, and the hollow portion of the molded article was cooled by passing water through the inside.

The extruder cylinder temperature was 150 ° C., 260 ° C., 265 ° C., 27 ° C. from the hopper side toward the die.
The temperature was set at 0 ° C., and the rotation speed of the screw was 10 RPM.

As a take-up device for a molded product, a pressure sizing system by pushing, which provides a reverse resistance to the propulsion of the molded product by providing a speed reducer and a friction brake on a take-up roll, was employed.

The bending strength load of the obtained double-sided walkway boundary block product is 26 KN, the dimensional tolerance is ± 2 mm, and it is JIS.
It passed the standard value.

Example 2 Using the same raw materials as in Example 1, using the same extruder as in Example 1, and under the same extrusion conditions as in Example 1, 250 × 250
A × 20 mm flat plate was extruded, and the mixing ratio of PET 100 parts by weight, andesite 10 parts by weight, and fly ash 10 parts by weight was used.
According to 0, mixing, pulverization and dehumidification were carried out to make the final water content of the composition 190 ppm. A 15% carbon-containing polytetrafluoroethylene liner was provided on the inner surfaces of the extrusion die and the sizing die. The temperature of the extruder was 150 ° C, 256 ° C, 258 ° C,
The temperature was set at 58 ° C., and the rotation speed of the screw was 15 RPM.

The obtained flat plate was a horticultural flat plate, and its bending strength load was 42 KN, which was judged to be a normal value.

Comparative Example 1 Extrusion molding was carried out using the same composition as in Example 1 and under the same conditions, but no taking-up by a pressure sizing method by pushing was performed. That is, the take-up device roll was not provided with a speed reducer and a friction brake.

As a result, the profile extrusion could not be carried out, and no matter how the extrusion temperature and the number of revolutions of the screw were changed, the profile extrusion could not be obtained.

[0036]

According to the present invention, the recovered PET bottles are effectively used to form an extruded article or a shaped extruded article having various solid or hollow cross-sections, for example, civil engineering blocks, horticultural articles, stationery, It is possible to produce daily necessities and molded products such as industrial, domestic pipes, conduits and thick plates. In addition, while maintaining specified performance and strength such as dimensions, tolerances, and bending strengths required for molded articles, performance such as aesthetics, coloring, and abrasion resistance can be imparted in some cases.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI // B29K 67:00 105: 26 (58) Investigated field (Int.Cl. ⁷ , DB name) B29C 47/00-47 / 96 B29B 17/00 C08K 3/00 C08K 3/04 C08L 67/02

Claims (1)

(57) [Claims] 1. A dehumidified pulverized material 100 of a recovered PET bottle
Parts by weight, 1 to 50 parts by weight of a carbonaceous substance selected from carbon black, charcoal, coal, coke, and fly ash, and 0 to 100 parts by weight of a dry and crushed igneous rock (0 to 100 parts by weight)
), The ratio of the feed zone: compression zone: metering zone of the screw of the extruder (3 to 4).
0): (1): (1 to 15), and a carbon or polytetrafluorocarbon liner is extruded using an extruder provided on the inner surface of an extrusion die and a sizing die, and is taken by a pressure sizing method by pushing. Extruding a recovered PET bottle.