KR101216228B1 - Continuous extruding process of polymers - Google Patents

Abstract

The present invention comprises the steps of: a) injecting a resin composition comprising a polymer resin and an additive into the extruder; b) melting the mixed composition and transferring the polymer melt to a die; c) injecting an organic-inorganic coating material lubricating the surface of the polymer into the die to form a molded body by extruding from the die while coating the surface of the polymer resin melt; It relates to a continuous extrusion method of crystalline and amorphous polymer resin comprising a.

Description

Continuous extruding process of polymers

The present invention relates to a continuous extrusion method of a polymer resin, a continuous extrusion to enable a continuous process while the polymer surface is coated by injecting an organic-inorganic material lubricating the surface of the polymer into the die during extrusion through a die It is about a method.

The conventional polymer continuous extrusion process was able to work at a resin temperature higher than the melting temperature (T _m ) of the resin in the case of the crystalline polymer or higher than the transition temperature (T _g ) in the case of the amorphous polymer. This is because when the resin temperature is lowered, the resin solidifies and sticks to the inner surface of the die, and continuous operation is impossible.

 In addition, in a difficult working environment in which the viscosity of the resin is very high or solidified, continuous extrusion is not possible, which leads to a phenomenon in which productivity is lowered.

The present invention is to provide a new continuous extrusion method of a polymer resin to be easily extruded by injecting an organic-inorganic coating material lubricating the surface of the polymer in order to facilitate the extrusion of the polymer.

The present invention is to enable the extrusion of the polymer melt with a very high viscosity, and to enable low-temperature extrusion, by introducing an organic-inorganic coating material that acts as a lubricating coating to the die to coat the surface of the extrudate, the polymer resin is It is an object of the present invention to provide a new continuous extrusion method of a polymer resin which is easily extruded.

The present invention is characterized by a method of continuously extruding a polymer resin capable of significantly lowering the extrusion pressure as well as a high viscosity polymer melt near the melting temperature of the resin. More specifically, in the continuous extrusion method of the polymer resin,

a) injecting a resin composition comprising a polymer resin and an additive into an extruder;

b) melting the mixed composition and transferring the polymer melt to a die;

c) injecting an organic-inorganic coating material lubricating the surface of the polymer into the die to form a molded body by extruding from the die while coating the surface of the polymer resin melt;

It includes.

More specifically, in the present invention, the temperature range of the die satisfies Equation 1 below for crystalline polymers, and satisfies Equation 2 below for non-crystalline polymers.

[Formula 1]

T _m -60 ℃ ≤ P _T ≤ T _m + 300 ℃

[Formula 2]

T _g -10 ° C <P _T <T _g +350 ° C.

(In Formulas 1 and 2, P _T is the temperature of the polymer resin in the die, T _m is the melting temperature of the crystalline polymer resin, T _g is the glass transition temperature of the amorphous polymer resin.)

Hereinafter, the present invention will be described more specifically.

In the present invention, the polymer resin may be a polymer resin alone, or a mixture of one or more polymer blends or polymer resins and additives different in kind. All polymers used in the extrusion process and in other continuous processes can be used.

Specifically, the polymer resin may be used as a crystalline polymer, an amorphous polymer or a mixture thereof.

Specific examples of the crystalline polymers include polyethylene, polypropylene, polyvinyl acetate copolymers, copolymers or blends thereof, and the like. Specific examples of the amorphous polymer resin include polyvinyl chloride, polystyrene, copolymers or blends thereof, and the like.

In addition, if necessary, additives commonly used in the art may be added. The additive is usually added in the melt extrusion process, it means an additive used to improve the physical properties of the polymer resin, the type is not limited. Specifically, for example, a blowing agent, a pigment, an organic filler, an inorganic filler, a plasticizer, and the like may be used, but are not limited thereto.

In the present invention, it is preferable to use an organic or inorganic coating agent having an viscosity of 500 PaS (= about 50 ⁵ mm ² / s) or less. When the viscosity of the organic-inorganic coating agent exceeds 500 PaS, it is generally higher than the polymer melt viscosity because the organic-inorganic coating agent does not flow between the polymer fluid and the die surface and tends to move to the center of the fluid. More specifically, the viscosity of the organic / inorganic coating agent is preferably in the range of 50 PaS or less.

The organic-inorganic coating agent may be specifically used, for example, water, silicone oil, ethylene glycol, canola oil, oligomer or synthetic oil. In addition, it is possible to use an organic and inorganic coating agent that is adjusted by mixing the thickener.

Polypropylene may be used as the polymer resin as an example of the present invention, and the extrusion temperature may be a polypropylene resin having a melting temperature (Tm) of 130 to 170 ° C, a MI of 0.1 to 50, and a specific gravity of 0.8 to 1.0. It is excellent in processability and is suitable for injecting organic-inorganic substances or oligomers. A polymer other than that can also be mixed and workability can be improved.

In the present invention, the resin composition is melt kneaded during continuous operation in an extruder, and in the process, additives and polypropylene resins are uniformly mixed, and in this case, the screw rotation speed is 10 to 50 rpm and the extrusion amount is 0.1 to 0.5 Kg /. h is preferred.

According to the present invention, by coating an organic material, an inorganic material or an oligomer, which is a solvent having a lower viscosity than that of the extrudate and insoluble in the polymer extrudate, the extrusion is continuously performed from a temperature lower than the melting temperature or the glass transition temperature of the polymer resin. It is characterized by manufacturing. Specifically, the temperature of the die preferably satisfies Expression 1 and Expression 2 below.

[Formula 1]

T _m -60 ℃ ≤ P _T ≤ T _m + 300 ℃

[Formula 2]

T _g -10 ° C <P _T <T _g +350 ° C.

(In Formulas 1 and 2, P _T is the temperature of the polymer resin in the die, T _m is the melting temperature of the crystalline polymer resin, T _g is the glass transition temperature of the amorphous polymer resin.)

More specifically, the organic-inorganic coating may be performed at a relatively low temperature, that is, a condition in which the viscosity of the polymer in the die is increased, that is, near a transition temperature (melting temperature T _{m for} crystalline polymers and glass transition temperature T _{g for} amorphous polymers). The injection and coating of the material makes it possible to extrude the polymer melt continuously. Therefore, the present invention is capable of continuous extrusion even in the range from the temperature T _m -60 ° C. to T _m + 300 ° C. and the T _g -10 ° C. to T _g + 350 ° C. where the high viscosity of the polymer melt is expected.

It is also meaningful to extend the range of continuous extrusion process conditions compared to working at a temperature above 50 ° C. above the melting temperature of the resin in a conventional extrusion process. In the conventional method, since the temperature inside the resin in the extruder must be maintained above the melting temperature, there is no limit in the physical properties of the extrudate of the polymer.

The present inventors have studied to solve the above problems, and as a result of injecting a low viscosity organic-inorganic coating material into the die, the viscosity of the polymer resin is very high or is present on the surface even at or below the melting temperature of the polymer resin. Extrusion through a new method of coating the substrate or oligomer, etc. solves this problem, and surprisingly found that the polymer molded body can be extruded from a melt of high viscosity at low temperature, thereby completing the present invention.

In the present invention, the organic-inorganic coating agent or oligomer, etc., it is preferable to use a material having a less viscosity than the polymer resin during the extrusion process, the polypropylene during the extrusion operation viscosity of about 300 Pa? S at 100 s ^-1 shear rate Therefore, the organic or inorganic substance or oligomer which is less than that is not limited. More preferably, it is not limited if it is a poor solvent including water. More preferably, an organic-inorganic coating agent having a viscosity of 500 PaS (= about 50 ⁵ mm ² / s) or less is used. The organic-inorganic coating agent may use a variety of oligomers or synthetic oils, such as silicone oil, ethylene glycol, canola oil, etc., it is preferable because water does not require post-treatment to wash.

Extrusion method according to the present invention can provide a new concept of extrusion process that can be extruded at a temperature near or below the transition temperature of a high viscosity polymer melt or polymer resin.

In addition, the continuous extrusion method according to the present invention is capable of extruding even in a state of high viscosity melt, and thus it is possible to continuously extrude from the die at or near the melting temperature of the polymer resin, and to reduce the extrusion pressure and reduce the torque. As the fuel cost of the energy is reduced, power consumption is reduced, manufacturing costs are reduced, and carbon dioxide emissions are reduced.

The present invention is a method that can work at a high viscosity of the polymer melt can significantly extend the continuous extrusion working temperature.

Conventionally, the resin temperature in the extruder should be maintained above the melting temperature, but can be adjusted to change the properties of the final extrudate.

In addition, the degree of freedom in die shape can be increased by reducing die swell, which is a critical parameter in the shape of the final extrudate.

Hereinafter, the present invention will be described in more detail with reference to one example, but the present invention is not limited to the following examples.

In the following Examples and Comparative Examples, the extruder was used for the continuous extrusion process, HAAKE Rheomex R252 (Single Screw Extruder). The extruder is 19 mm in diameter, 25 L / D single screw type and has three heating zones in the extruder. Each heating zone is temperature controlled by a computer. In particular, four sensor ports are provided in the barrel to directly measure the actual pressure distribution in the extruder or the temperature of the molten resin. The optimal location to be injected can be determined.

Extruder specifications are shown in Table 1 below.

[Table 1]

A screw having a mixing head at a compression ratio of 3: 1 was used. The die used a capillary nozzle having a diameter of 1 mm and an L / D of 20.

Physical properties were measured by the following method.

HAAKE's Rheomix R252 extruder can control and measure temperature through the HAAKE PolyLab OS-System (computer program), as well as measure the torque value of the motor five times per second when the screw is rotated. ) Value. The pressure is also measured five times per second on a computer via a pressure sensor connected to the die and displayed as graphs and data values.

1) pressure of extruder

The pressure of the extruder or the die was measured by directly contacting the polymer resin with a pressure sensor for dynicsco's polymer resin.

2) torque of extruder

The torque measurement of the Rheomix R252 extruder by HAAKE was measured with the torque measuring device (measurement method using a load cell machine) equipped with this extruder.

[Example 1]

For the continuous extrusion process, an extruder was used by HAAKE Rheomex R252 (Single Screw Extruder). The extruder is 19 mm in diameter, 25 L / D single screw type and has three heating zones in the extruder. Each heating zone is temperature controlled by a computer. In particular, four sensor ports are provided in the barrel to directly measure the actual pressure distribution in the extruder or the temperature of the molten resin. The optimal location to be injected can be determined.

A screw having a mixing head at a compression ratio of 3: 1 was used. The die used a capillary nozzle having a diameter of 1 mm and an L / D of 20.

Polypropylene copolymer was used Honam Co., Ltd. SEP750 (melting point 131 ℃), was used to dry the moisture content to less than 0.1%.

In a continuous process, two pressure sensors on the extruder barrel, one pressure sensor on the die, and a static mixer are installed for proper control of the temperature of the polypropylene copolymer and pre-heated for 20 minutes at the set temperature. It was.

To 100 parts by weight of polypropylene copolymer, 2 parts by weight of talc was used as an additive, and a resin composition raw material mixed with a resin was added to a hopper to rotate a screw. At this time, the screw rotation speed was 20 rpm and the extrusion amount was 0.2 Kg / h.

The extruder barrel temperature was adjusted to 70 ° C., 180 ° C. and 180 ° C., respectively, and gradually cooled in a static mixer, the temperature of the extruder head was adjusted to 160 ° C., and the silicon oil (Shin-Etsu) was extruded while maintaining cooling inside the die. Product name: KF-96-20CS, specific gravity: 0.95, viscosity: 20mm ² / s (= 0.019 Pa? S, at 25 ° C) was injected at 0.03kg / h, and the surface of the extrudate was passed through the dies. It was coated and then extruded through a die.Silicone oil was injected into the die using a pump (manufactured by Mahr), and liquid was filled in the grooves of the rotating gear when the gear engagement at the inlet of the pump was released. At this time, when liquid is filled in the space created by gear casting and plate, it moves along the inner circumference of the casing to the discharge side, and the liquid flows by gear engagement at the discharge port. A stainless steel tube connected to the discharge port was inserted into the die through a groove formed in the die, at which the injection speed of the pump was 50 rpm and the temperature of the silicone oil injected from the pump was 140 ° C.

At this time, the end of the die, that is, the resin temperature immediately before being discharged from the die was adjusted to 140 ° C (= Tm + 9 ° C).

As a result, the extrudate was obtained at a lower temperature than near the melting point and higher than the general extrusion state of 9 ° C.

When the pressure and torque of the screw in the extruder barrel were measured, the pressure was 19 ~ 20bar and the torque was about 700 ~ 900Ncm. After continuous working for one hour, the resin was continuously stably extruded.

[Example 2]

The same experiment as in Example 1 except that the temperature of the die was changed in Example 1.

That is, the end of the die, that is, the temperature just before the discharge, was adjusted to 125 ° C. in order to control the low temperature of the extrudate upon discharge from the die. An extrudate at a low temperature of 5 ° C. below the melting point was obtained.

At this time, when the pressure and torque of the screw in the extruder barrel were measured, the pressure was 30 to 33 bar and the torque was 1200 to 1500 Ncm. Experiments continuously for one hour showed that the resin was extruded continuously and stably.

[Example 3]

The experiment was the same as in Example 1 except that the type of the resin was changed using low density polyethylene (Hanhwa Co., Ltd. LDPE 960 (MI = 3) melting point 114 ℃) as a polyolefin resin in Example 1.

That is, the temperature of the end of the die, that is, the temperature just before the discharge, was adjusted to 100 ° C. in order to adjust the low temperature of the extrudate upon discharge from the die. An extrudate at a low temperature of 14 ° C. below the melting point was obtained.

At this time, as a result of measuring the pressure and torque of the screw in the extruder barrel, the pressure was 26 ~ 28bar and the torque was 1000 ~ 1300Ncm. Experiments continuously for one hour showed that the resin was extruded continuously and stably.

Example 4

Except that the low-density polyethylene (Hanhwa Co., Ltd. LDPE 960 (MI = 3) melting point 114 ℃) using a polyolefin resin in Example 1, while experimenting while changing the temperature in the extruder die as shown in Table 2 below An extrudate was prepared in the same manner as in Example 1. The temperature of the band heater attached to the barrel of the extruder is represented by C1, C2, C3. In preparing the extrudate, the torque of the screw in the extruder barrel and the pressure in the die are measured and shown in Table 2 below.

[Table 2]

Experiments were carried out under the conditions as shown in Table 2, when the silicon oil is added even in the temperature range of the melting point or more of the resin, the pressure was reduced and the torque was also reduced to be able to see a phenomenon that the extrusion is stable.

[Example 5]

Taesung Electric Field's VCX-01 was used as a compound including 30 parts by weight (phr) of TOTM (Trioctyl Trimellitate) in 100 parts by weight (phr) of PVC (weight average molecular weight 1300, Tg = 70 ° C.). It was placed in a hopper and worked by rotating the extruder screw. At this time, the screw rotation speed was 20 rpm and the extrusion amount was 0.21 Kg / h.

The other extruder used the same thing as Example 1, and used the same silicone oil.

In Table 3, experiments were performed with varying temperatures at the extruder die. The temperature of the band heater of the extruder was represented by C1, C2, C3.

[Table 3]

As the die temperature rose, it became easier to add oil, and when oil was added, the pressure dropped to the lowest, the torque decreased, and the work became stable.

[Comparative Example 1]

Except that the silicone oil was not injected in Example 2 was the same as in Example 1.

That is, the end of the die, that is, the temperature just before being discharged, was adjusted to 125 ° C. in order to control the extrudate at low temperature upon exit from the die. The extrudate was cooled and solidified and was not discharged from the die, making continuous processing impossible.

As a result of measuring the pressure and torque of the screw in the extruder barrel, the experiment was set to 550 bar to protect the extruder equipment. The extruder was stopped beyond 550 bar, the pressure was over 550 bar, and the torque could not be continuously extruded at 4000 Ncm.

Claims (7)

a) injecting a resin composition comprising a polymer resin and a foaming agent, a pigment, an organic filler, an inorganic filler and a plasticizer into the extruder;
b) melting the mixed resin composition and transferring a polymer melt to a die;
c) injecting an organic / inorganic coating agent lubricating the surface of the polymer melt into the die to form a molded body by extruding from the die while coating the surface of the polymer melt;
Continuous extrusion method of the polymer resin comprising a. The method of claim 1,
The temperature range of the die satisfies Equation 1 below for crystalline polymers, and satisfies Equation 2 below for non-crystalline polymers.
[Formula 1]
T _m -60 ℃ ≤ P _T ≤ T _m + 300 ℃
[Formula 2]
T _g -10 ° C <P _T <T _g +350 ° C.
(In Formula 1 and Formula 2, P _T is the temperature of the polymer resin in the die, T _m is the melting temperature of the crystalline polymer resin, T _g is the glass transition temperature of the amorphous polymer resin.) The method of claim 1,
The organic-inorganic coating agent is a continuous extrusion method of a polymer resin using an organic or inorganic material having a viscosity of 500 PaS or less. The method of claim 3,
The organic-inorganic coating agent is a water, silicone oil, ethylene glycol, canola oil, oligomer or synthetic oil continuous extrusion method of the polymer resin. The method of claim 1,
The polymer resin is a continuous extrusion method of the polymer resin is a polymer resin alone or a blend of two or more kinds of extrusion process possible. 6. The method of claim 5,
The polymer resin is a continuous extrusion method of the polymer resin is a crystalline polymer resin, an amorphous polymer resin or a mixture thereof. The method according to claim 6,
The crystalline polymer resin is polyethylene, polypropylene, polyvinyl acetate copolymers and copolymers or blends thereof, and the amorphous polymer resin is polyvinyl chloride, polystyrene, and the continuous extrusion of the polymer resin is a copolymer or blend thereof Way.