WO2016052958A1

WO2016052958A1 - Polymer powder and method for preparing same

Info

Publication number: WO2016052958A1
Application number: PCT/KR2015/010225
Authority: WO
Inventors: 강경민; 강성용; 신준범; 황덕율
Original assignee: (주)엘지하우시스
Priority date: 2014-09-29
Filing date: 2015-09-25
Publication date: 2016-04-07

Abstract

Provided is a polymer powder having an average particle diameter of 20-300 μm, wherein particles with a particle diameter of smaller than 10 μm account for 10 mass% or less, and particles with a particle diameter of greater than 300 μm account for 10 mass% or less. In addition, provided is a method for preparing the polymer powder, the method comprising the steps of: forming a molten material of a polymer; feeding a super critical fluid to the molten material of the polymer to form a mixed composition; and spraying the mixed composition to prepare a polymer powder.

Description

Polymer powder and preparation method thereof

It relates to a polymer powder and a method for producing the same.

Thermoplastic Composites applied to interior materials or components used in construction, vehicles and filters may include polymer powders for various purposes, for example, they may include structures in which the powders are impregnated into fibers. . In the case of such a polymer powder, the smaller the particle size, the more advantageous the subsequent process, and the narrower the particle size distribution and the uniform size, the more various applications can be secured. Conventionally, it is intended to produce spherical fine particles at low cost using a ball mill grinding method or a freeze grinding method. However, the freeze grinding method has to use expensive nitrogen in order to reduce the size of the particles, there is a problem in terms of cost and time because it undergoes a multi-step grinding process. In addition, since the final particles produced by the freeze grinding method have a relatively sharp fracture shape, there is a problem in that it is disadvantageous in terms of fluidity and thus various applications cannot be secured. In the case of the ball mill grinding method, the particle shape is closer to the spherical shape than the freeze grinding, but in order to obtain such spherical particles, a separate process of dispersing and recovering them in a solvent is required, which is also disadvantageous in terms of cost and time. And, the particle size distribution of the produced particles is wide and nonuniform, there is a problem that aggregation occurs well.

Therefore, there is a need for a method for producing spherical powder, which is advantageous in terms of cost and time and has a small change in physical properties due to temperature and the like in the manufacturing process, and has a narrow and uniform particle size and excellent physical properties.

One embodiment of the present invention provides a polymer powder having a narrow particle size distribution and uniform particle size in a certain range, thereby ensuring excellent fluidity and applicability.

Another embodiment of the present invention is advantageous in terms of cost and time, and provides a method for producing the polymer powder capable of minimizing physical property changes with temperature and the like.

In one embodiment of the invention, a polymer having an average particle diameter of about 20 μm to about 300 μm, particles having a particle size of less than about 10 μm or less, and particles having a particle size of greater than about 300 μm of about 10 mass% or less Provide powder.

The polymer powder is polylactic acid (PLA), polypropylene, polystyrene, acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), polyethylene glycol (PEG), thermoplastic polyurethane (TPU), polydimethyl Siloxane (PDMS), high density polyethylene (HDPE), low density polyethylene (LDPE), high impact polystyrene (HIPS), polyethylene oxide (PEO), polyethylene carbonate (PEC), polyhydroxyalkanoate (PHA), poly At least one selected from the group consisting of hydroxybutyrate (PHB) and combinations thereof.

The polymer powder may have a weight average molecular weight (Mw) of about 10,000 to about 300,000.

The polymer powder may have an angle of repose less than about 45 degrees.

In another embodiment of the invention, forming a melt of the polymer; Injecting a supercritical fluid into the melt of the polymer to form a mixed composition; And it provides a method for producing a polymer powder comprising the step of preparing a polymer powder by spraying the mixed composition.

The melt of the polymer may be formed by melting the polymer at about 100 ° C to about 290 ° C.

The forming of the mixed composition may include adding the supercritical fluid to the melt of the polymer and then pressing the dispersion to disperse the supercritical fluid in the melt of the polymer.

Forming the mixed composition may be a step of pressing the supercritical fluid to a melt of the polymer to a pressure of about 50 bar to about 500 bar.

The mixed composition may be formed by adding about 5 to about 15 parts by weight of the supercritical fluid based on 100 parts by weight of the melt of the polymer.

The supercritical fluid may include at least one selected from the group consisting of carbon dioxide, helium, nitrogen, methane, ethane, propane, ethylene, propylene, methylene, and combinations thereof.

The mixed composition may have a viscosity of about 10 ⁻³ Pa · s to about 10 ³ Pa · s.

Spraying the mixed composition to prepare a polymer powder may be spraying the mixed composition through a nozzle having an average aperture of about 0.01 to about 3.0 mm.

The spraying of the mixed composition to prepare a polymer powder may include cooling the mixed composition at about −30 ° C. to about 30 ° C. simultaneously with the spray.

The weight average molecular weight (Mw) difference between the polymer and the polymer powder may be about 200,000 or less.

The thermal decomposition temperature difference between the polymer and the polymer powder may be about 50 ° C or less.

The polymer powder has a narrow particle size distribution and a small and uniform particle size, thereby ensuring excellent fluidity and applicability.

Method for producing the polymer powder is advantageous in terms of cost and time, it is possible to produce the polymer powder having excellent physical properties by minimizing the change in physical properties according to the temperature.

Figure 1 (a) is a SEM photograph of a polymer powder prepared according to an embodiment of the present invention, (b) is a SEM photograph of a polymer powder prepared according to a conventional manufacturing method.

Figure 2 shows a particle size distribution graph according to the particle diameter of the polymer powder prepared according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, by which the present invention is not limited and the present invention is defined only by the scope of the claims to be described later.

The polymer powder has an average particle diameter of about 20 μm to about 300 μm, and by having an average particle diameter in the above range, when applied to interior building materials and interior decoration materials based on particle size, it is possible to secure excellent processability.

In addition, the polymer powder has a particle diameter of less than about 10 μm and particles having a particle size of greater than about 300 μm, respectively, 10 mass% or less, and may be, for example, about 5 mass% or less. Specifically, the particles having a particle diameter of less than about 10 μm may be about 5 mass% or less, and the particles having a particle diameter of about 300 μm or less may be about 1 mass% or less. Since the polymer powder has such a particle size distribution, excellent fluidity and formability can be ensured when applied to interior building materials and interior decoration materials.

Specifically, the polymer powder is polylactic acid (PLA), polypropylene, polystyrene, acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), polyethylene glycol (PEG), thermoplastic polyurethane (TPU) , Polydimethylsiloxane (PDMS), high density polyethylene (HDPE), low density polyethylene (LDPE), high impact polystyrene (HIPS), polyethylene oxide (PEO), polyethylene carbonate (PEC), polyhydroxyalkanoate (PHA) ), Polyhydroxybutyrate (PHB), and combinations thereof.

For example, the polymer powder may include polylactic acid, and in this case, it may be easy to prepare a polymer powder having an average particle diameter and particle size distribution in the above range by the manufacturing method described below. In addition, due to the average particle diameter and particle size distribution in the above range, not only excellent fluidity and processability can be secured, but also an environmentally friendly effect due to polylactic acid itself can be obtained.

The polymer powder may have a weight average molecular weight (Mw) of about 10,000 to about 300,000, for example, about 50,000 to about 200,000. The polymer powder satisfies the weight average molecular weight (Mw) in the range together with the average particle diameter and particle size distribution in the above range, thereby ensuring excellent fluidity and formability, and at the same time, the interior materials and the like to which the same is applied can secure excellent strength. have.

The polymer powder may have an angle of repose less than about 45 degrees, for example less than about 40 degrees. The 'rest angle' refers to the maximum inclination angle that can maintain the inclination when the granulated material is stacked on the plane in a natural state. Specifically, the angle of repose can be measured by the injection stabilization angle measuring method for measuring the angle of the inclined plane and the horizontal plane of the pile with respect to the pile formed by pouring the granulated material on a flat horizontal plane, and replaces the container having a flat bottom With respect to the shape of the cockle formed while the material is discharged through the hole made in, it can be measured by the discharge stabilization angle measuring method for measuring the angle formed by the inclined surface and the bottom surface of the flat shape. When the polymer powder exhibits a repose angle in the above range, excellent fluidity can be secured and applicability in various fields can be secured.

Another embodiment of the invention comprises forming a melt of a polymer; Injecting a supercritical fluid into the melt of the polymer to form a mixed composition; And it provides a method for producing a polymer powder comprising the step of preparing a polymer powder by spraying the mixed composition.

The polymer powder is prepared using a super critical fluid (SCF), and specifically, the supercritical fluid may be used as an additive. As a result, the production method can prevent the loss of raw materials because the polymer powder can be prepared at a relatively low temperature, and the polymer powder prepared by the production method can secure excellent physical properties in terms of thermal decomposition, particle size distribution, and molecular weight. .

Specifically, the method may include forming a melt of the polymer. The melt of the polymer is formed by melting a raw material composed of a polymer at a predetermined temperature, and the raw material composed of the polymer may be pellet-shaped granules.

The melt of the polymer may be formed by melting the polymer at about 100 ° C to about 290 ° C. The polymer may be melted to have an appropriate viscosity without melting the physical properties of the polymer itself by melting at a temperature in the above range.

The melt of the polymer may have a viscosity of about 10 ⁻³ Pa · s to about 10 ³ Pa · s. The melt of the polymer can be well mixed with the supercritical fluid in subsequent steps by having a viscosity in the above range, and can ensure excellent processability.

The manufacturing method may include the step of adding a supercritical fluid to the melt of the polymer to form a mixed composition. The supercritical fluid is introduced after the melt of the polymer is formed, thereby forming a mixed composition having an appropriate viscosity at a relatively low temperature.

Specifically, the forming of the mixed composition may include dispersing the supercritical fluid in the melt of the polymer by injecting the supercritical fluid into the melt of the polymer. That is, the mixed composition may be mixed in a state in which the supercritical fluid is dispersed in the melt of the polymer.

In this case, the step of forming the mixed composition may be a step of pressing the supercritical fluid to the melt of the polymer to a pressure of about 50 bar to about 500 bar, for example, about 50 bar to about Pressurizing to a pressure of 300 bar. By pressurizing the pressure to maintain the range in this step, the supercritical fluid can be uniformly dispersed in the melt of the polymer and form a mixed composition having a viscosity advantageous for processing.

In addition, the forming of the mixed composition may be performed at about 100 ℃ to about 290 ℃. Conventionally, when preparing a particle shape by melting a polymer or a polymer raw material by spraying or the like, the temperature is raised to a high temperature of about 300 ° C. or more to control the viscosity of the melt. When the manufacturing process is performed at such a high temperature, there is a problem that the loss of the raw material is increased and the manufacturing cost is increased, and the thermal properties of the resulting particle shape are not good. In this regard, the manufacturing method is such that the step of forming the mixed composition is carried out at a temperature in the range, thereby uniformly mixing with the supercritical fluid without damaging the physical properties of the polymer melt to form a mixed composition having an appropriate viscosity. And the resulting polymer powder can exhibit excellent thermal properties.

The forming of the mixed composition may be a step in which the melt of the polymer is injected while the melt of the polymer is injected. At this time, the melt of the polymer may be injected at a rate of about 2 to about 100 rpm, and the supercritical fluid may be injected of the melt of the polymer at a flow rate of about 0.01 to about 40 g / l. The melt of the polymer and the supercritical fluid can be injected and dispersed evenly by injecting at a rate and a flow rate in the above range, and the mixed composition thus prepared can easily ensure a viscosity advantageous for processing.

The mixed composition may be formed by adding about 5 to about 15 parts by weight of the supercritical fluid based on 100 parts by weight of the melt of the polymer. The supercritical fluid is added in a small amount compared to the polymer melt, and the polymer melt is mixed with it at a relatively low temperature, thereby easily preparing a mixed composition having a viscosity advantageous for processing without deterioration of thermal properties.

When the supercritical fluid is included in less than about 5 parts by weight relative to 100 parts by weight of the melt of the polymer, the mixed composition has a problem that it is difficult to secure a viscosity advantageous for processing, and when included in excess of about 15 parts by weight. There is a fear that phase separation of supercritical fluid occurs.

The supercritical fluid is a fluid present in the state of exceeding the critical temperature and the critical pressure inherent in the material and exhibits the properties of both gas and liquid, specifically, carbon dioxide, helium, nitrogen, methane, ethane, propane, ethylene, propylene, methylene And at least one selected from the group consisting of a combination thereof. For example, the supercritical fluid may comprise carbon dioxide, in which case it is possible to secure the advantages of relatively low cost and good mixing with the melt of the polymer.

The mixed composition prepared by injecting the supercritical fluid into the melt of the polymer may have a viscosity of about 10 ⁻³ Pa · s to about 10 ³ Pa · s. Since the mixed composition has a viscosity in the above range, it is easy to spray it to ensure excellent processability in the production of the polymer powder, thereby the polymer powder prepared may have a uniform size and narrow particle size distribution.

The manufacturing method may include the step of preparing a polymer powder by spraying the mixed composition. Specifically, the mixed composition may be sprayed through a nozzle, and specifically, the average diameter of the nozzle may be about 0.01 to about 3.0 mm. The average composition of the nozzle satisfies the above range so that the mixed composition can be easily introduced, from which polymer powder having an appropriate size and narrow particle size distribution can be produced.

Specifically, the mixed composition may be injected after being injected with air in the nozzle, the temperature of the injected air may be about 200 ℃ to about 500 ℃, the pressure may be about 100 psi to about 1000 psi . In addition, the injection speed of the air may be about 10 m / s to about 50 m / s. The mixed composition is injected into a nozzle having a diameter in the range together with air satisfying the temperature, pressure and injection speed in the above range, so that the polymer powder prepared by spraying it can easily secure a proper size and narrow particle size distribution. And may not impair the physical properties of the polymer itself.

In addition, the step of preparing the polymer powder by spraying the mixed composition may be the step of cooling the mixed composition at a temperature of about -30 ℃ to about 30 ℃ at the same time as the spray. As the mixed composition is cooled at a temperature in the above range at the same time as the spraying, the uniformity of the polymer powder size can be improved and a narrow particle size distribution can be satisfied. In addition, it is possible to secure excellent fluidity without aggregation of the polymer powder, it is possible to maintain the spherical shape well.

In the method of preparing the polymer powder, it is possible to secure an appropriate viscosity at a relatively low temperature by using a supercritical fluid. As a result, the manufacturing method can minimize the loss of raw materials due to heat, and there is little change in physical properties such as thermal properties and molecular weight of the polymer powder relative to the raw materials, thereby obtaining advantages in terms of cost and excellent physical properties.

Specifically, the raw material for producing the polymer powder is a polymer, and the polymer means a state before forming a melt of the polymer. In this case, a difference in weight average molecular weight (Mw) of the polymer and the polymer powder may be about 200,000 or less, for example, about 150,000 or less, for example, about 5,000 to 150,000. The smaller the difference in the weight average molecular weight (Mw) means less loss of raw materials in the manufacturing process of the polymer powder, the change in weight average molecular weight (Mw) compared to the raw material of the polymer powder satisfies the above range, The polymer powder can easily secure excellent physical properties due to the properties of the polymer itself.

In addition, the thermal decomposition temperature difference between the polymer and the polymer powder may be about 50 ° C or less, for example, about 20 ° C or less, for example, may be about 2 ° C to 20 ° C. The 'pyrolysis temperature' is a measurement of the temperature at which the polymer is decomposed by applying heat to the polymer, and specifically, it may be measured using a pyrolysis analyzer (TGA). The smaller the difference in pyrolysis temperature is, the smaller the change in physical properties of the raw materials in the manufacturing process of the polymer powder, and the difference in thermal decomposition temperature of the polymer and the polymer powder satisfies the above range, whereby the polymer powder Excellent physical properties due to can be easily secured.

The following presents specific embodiments of the present invention. However, the embodiments described below are merely for illustrating or explaining the present invention in detail, and thus the present invention is not limited thereto.

<실시예 및 비교예><Examples and Comparative Examples>

Example 1

A pellet-like polylactic acid resin was introduced into an extruder, and the polylactic acid resin was melted at a temperature of 250 ° C. to prepare a polylactic acid melt. Subsequently, 5 parts by weight of carbon dioxide supercritical fluid was added to 100 parts by weight of the polylactic acid melt, followed by pressure mixing and dispersing to prepare a mixed composition. Subsequently, the mixed composition was injected into a spray nozzle, sprayed into a chamber having a temperature of 20 ° C, and cooled to prepare a polylactic acid powder.

Comparative Example 1

Pellet-shaped polylactic acid resin was freeze-pulverized, and polylactic acid powder was prepared through a ball-mill process.

Comparative Example 2

A pellet-like polylactic acid resin was introduced into an extruder, and the polylactic acid resin was melted at a temperature of 250 ° C. to prepare a polylactic acid melt. The polylactic acid powder was prepared by heating the polylactic acid melt to 400 ° C, injecting it into a spray nozzle, spraying the same in a chamber having a temperature of 20 ° C, and simultaneously cooling.

<평가><Evaluation>

Experimental Example 1 Measurement of Average Particle Size and Particle Size Distribution

For Example 1 and Comparative Example 1, the average particle diameter and particle size distribution were measured using a laser diffraction particle size distribution analyzer (Microtrac, S3500 Series), and are shown in Table 1 below. In addition, a photograph of the polylactic acid powder prepared according to Example 1 is shown in FIG. 1 (a), and a photograph of the polylactic acid powder prepared according to Comparative Example 1 is described in FIG. 1 (b). It was. In addition, a particle size distribution graph according to the particle diameter of the polymer powder of Example 1 is described in FIG. 2.

Table 1

	Average particle size (㎛)	Particles of less than 10 μm in particle size (mass%)	Particles (mass%) with a particle diameter greater than 300 µm
Example 1	70	4	0.45
Comparative Example 1	40	5	20

Experimental Example 2: Weight average molecular weight (Mw) and pyrolysis temperature (T _decdec ) Measure the difference

For Examples 1 and 2, the weight average molecular weight (Mw) of each of the pellet-shaped polylactic acid resin and the prepared polylactic acid powder as raw materials was measured to derive the difference, and thermogravimetric analysis (TGA). Each pyrolysis temperature (T _dec ) was measured using) to derive the difference. The results are shown in Table 2 below.

TABLE 2

	Weight average molecular weight (Mw)			Pyrolysis Temperature (℃)
	Pellet	powder	△ Mw	Pellet	powder	△ T _dec
Example 1	200,000	100,000	100,000	347.54	345.20	2.34
Comparative Example 2	200,000	30,000	170,000	347.54	310.20	37.34

Referring to the results of Table 1 and Figure 2, the polylactic acid powder of Example 1 prepared according to an embodiment of the present invention having an average particle diameter of 20 ㎛ to 300 ㎛, It turns out that all the particle | grains more than 300 micrometers have particle size distribution which is 10 mass% or less.

In addition, through the results of Figure 1, it can be seen that the polylactic acid powder of Example 1 is produced according to the method for producing a polymer powder according to an embodiment of the present invention exhibits an average particle size range of the above range in the shape of a sphere. .

On the other hand, it can be seen that the polylactic acid powder of Comparative Example 1 prepared through freeze grinding and ball-mill processes has a larger average particle diameter and an uneven particle size distribution than Example 1.

In addition, when referring to the results of Table 2, the polylactic acid powder of Example 1 prepared according to an embodiment of the present invention, compared to Comparative Example 2, the weight average molecular weight of the raw material in the form of pellets during the manufacturing process reduced And it can be seen that the change in the pyrolysis temperature is small, thereby implementing better physical properties due to the polylactic acid itself.

Claims

The average particle diameter is 20 µm to 300 µm,

10 mass% or less of particle | grains whose particle diameter is less than 10 micrometers, and 10 mass% or less of particle | grains whose particle diameter is more than 300 micrometers

Polymer powder.
The method of claim 1,

The polymer powder is polylactic acid (PLA), polypropylene, polystyrene, acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), polyethylene glycol (PEG), thermoplastic polyurethane (TPU), polydimethyl Siloxane (PDMS), high density polyethylene (HDPE), low density polyethylene (LDPE), high impact polystyrene (HIPS), polyethylene oxide (PEO), polyethylene carbonate (PEC), polyhydroxyalkanoate (PHA), poly At least one selected from the group consisting of hydroxybutyrate (PHB) and combinations thereof

Polymer powder.
The method of claim 1,

The polymer powder has a weight average molecular weight (Mw) of 10,000 to 300,000

Polymer powder.
The method of claim 1,

The polymer powder has an angle of repose less than 45 degrees.

Polymer powder.
Forming a melt of the polymer;

Injecting a supercritical fluid into the melt of the polymer to form a mixed composition; And

Spraying the mixed composition to produce a polymer powder

Method for producing a polymer powder.
The method of claim 5,

The melt of the polymer is formed by melting the polymer at 100 ° C to 290 ° C.

Method for producing a polymer powder.
The method of claim 5,

Forming the mixed composition,

And injecting the supercritical fluid into the melt of the polymer to pressurize to disperse the supercritical fluid in the melt of the polymer.

Method for producing a polymer powder.
The method of claim 7, wherein

Forming the mixed composition,

Injecting the supercritical fluid into the melt of the polymer and pressurizing it to a pressure of 50 bar to 500 bar

Method for producing a polymer powder.
The method of claim 5,

The mixed composition is formed by adding 5 to 15 parts by weight of the supercritical fluid based on 100 parts by weight of the melt of the polymer.

Method for producing a polymer powder.
The method of claim 5,

The supercritical fluid includes at least one selected from the group consisting of carbon dioxide, helium, nitrogen, methane, ethane, propane, ethylene, propylene, methylene and combinations thereof

Method for producing a polymer powder.
The method of claim 5,

The mixed composition has a viscosity of 10 −3 Pa · s to 10 3 Pa · s

Method for producing a polymer powder.
The method of claim 5,

Spraying the mixed composition to prepare a polymer powder,

Spraying the mixed composition through a nozzle having an average aperture of 0.01 to 3.0 mm

Method for producing a polymer powder.
The method of claim 5,

Spraying the mixed composition to prepare a polymer powder,

Cooling the mixed composition at -30 ° C to 30 ° C at the same time as the spraying;

Method for producing a polymer powder.
The method of claim 5,

The weight average molecular weight (Mw) difference between the polymer and the polymer powder is 200,000 or less

Method for producing a polymer powder.
The method of claim 5,

Pyrolysis temperature difference between the polymer and the polymer powder is 50 ℃ or less

Method for producing a polymer powder.