JP2016204649A - Polymer particle of soft polymer and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a problem that polymer particles adhere to each other when moldability is enhanced by increasing melt flow property (MFR) of a polymer in a propylene-based α-olefin block copolymer of a soft polymer, to efficiently remove residual volatile components from the polymer particles and further to suppress blockage of a silo or the like by crimp of the polymer particles.SOLUTION: There is provided polymer particles of a soft polymer satisfying following requirements: a) a component eluted at 40°C or less is 23 wt.% or more in TREF (temperature raise elution fractionation); b) a volatile component of the polymer particles is 100 wt.ppm or less; and c) a repose angle of the polymer particles of 20 to 55°.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polymer particle of a soft polymer that is excellent in fluidity and moldability and has few volatile components. More specifically, the present invention relates to high melt fluidity, excellent moldability, and the polymer is easily sticky. Suppresses the problem of coalesced particles adhering to each other, and does not cause clogging when the polymer particles of the soft polymer are stacked in a silo and has low volatile content, so it can be used safely in the next granulation process It relates to polymer particles of a soft polymer.

  Olefin-based thermoplastic elastomers, which are main polymers of olefin-based polymers, are widely used as industrial materials, and olefin-based thermoplastic elastomers are random typified by copolymers of propylene and ethylene or α-olefins. Blends of components such as copolymers are well known, have moderate flexibility and strength, have good other physical properties, are highly adaptable to environmental issues such as recycling and incineration, and are lightweight and formable and economical. Therefore, it is used in a wide range of fields as molded products such as films, sheets, fibers, nonwoven fabrics, various containers, and polymer modifiers.

  Among such thermoplastic elastomers, what is referred to as a so-called propylene-based block copolymer that produces a polypropylene component in the first step and a propylene and ethylene or α-olefin copolymer in the second step is a random copolymer. Excellent heat resistance and productivity compared to elastomers, and for elastomers manufactured by mechanical mixing, because it can reduce manufacturing costs, it is economical and excellent in various physical properties. Recently, it has been widely used (see Patent Documents 1 and 2).

  In the so-called propylene-based block copolymer in which the polypropylene component is produced in the first step and propylene and ethylene or α-olefin copolymer is produced in the second step, the moldability is reduced in order to shorten the molding cycle. In order to improve further, it is required to increase the melt fluidity (MFR) of the polymer, and for this purpose, the propylene-based polymer in the first step or the propylene and ethylene or α-olefin copolymer in the second step. If the MFR is increased, that is, the molecular weight is decreased, the polymer is easily sticky, the polymer particles adhere to each other, and the polymer particles are difficult to handle, and the appearance of the molded product is deteriorated. It has become.

  In addition, in such a soft polymer, the amount of monomer dissolved in the polymer powder accompanying an increase in the amorphous component (non- (low) crystalline component) increases the monomer of the polymer powder in the current drying equipment. Residue increased. To solve this problem, there is a solution that raises the drying temperature and lengthens the drying time, but that is not enough, and more effective residual volatile matter can be obtained by nitrogen aeration after the drying process, that is, aeration. Is also necessary (see Patent Documents 3 to 6).

That is, in the method for producing a soft olefin polymer, it is necessary to remove residual volatile components such as residual monomer and residual solvent from the produced polymer particles. For example, 5,000 wtppm or more of residual volatile components may be contained immediately after production and immediately after discharge from the polymerization reactor.
Therefore, it is necessary to remove the residual volatile content of the polymer particles immediately after the production, and as a method therefor, Patent Document 3 describes a method of removing the residual volatile content by controlling the temperature of the aeration gas of the silo. . However, when the aeration gas falls below a certain temperature, not only the residual volatile components cannot be removed, but also there is a risk of promoting the fixing of the polymer powder and causing silo blockage. On the other hand, when the temperature of the drying process is extremely high, silo blockage occurs regardless of the temperature of aeration. Therefore, the conditions described in Patent Document 3 alone are insufficient for drying without blocking.

  Such a polymer powder of a soft polymer contains many amorphous components (non- (low) crystalline components), and therefore, when heated in the drying process, the amorphous components bleed (exude) on the powder surface, and polyolefin When cooled by nitrogen ventilation in a large silo facility such as a manufacturing facility, the bleed amorphous component becomes a contact point between the powders, and there is a problem that the polymers are fixed. In particular, when storing a large amount of polymer powder as in a silo, the polymer powder deforms due to its own weight, the adhesion area between the polymer powders increases, and the adhesion between the polymers is There is also a concern that it will become larger and cannot be extracted from silos.

  For example, as a result of examination according to the description in Patent Document 6, a polymer powder composed of a propylene-based block copolymer containing an amorphous component can be fixed in a nitrogen aeration in a silo after the drying step and extracted from the silo. There wasn't.

  In order to shorten the molding cycle and improve the moldability of the propylene block copolymer, which is an industrially superior elastomer material, the polymer melt fluidity (MFR) is increased. As a result, it becomes necessary for the polymer to become sticky and to prevent the problem of polymer particles adhering to each other, and from the polymer particles, residual volatilization such as residual monomer and residual solvent is required. In addition, it is necessary to efficiently and sufficiently remove the component, and further, when storing the polymer particles, it is necessary to suppress clogging of silos due to the pressure bonding of the polymer particles.

JP 2001-226435 A JP 2005-220235 A JP 2004-189913 A US Pat. No. 4,365,057 Japanese Patent No. 5161730 JP 2002-327008 A

  The object of the present invention, that is, the problem to be solved by the present invention is to reduce the cycle at the time of molding in a soft polymer that is an industrially superior elastomer material such as a propylene-based block copolymer in view of the above-mentioned conventional problems. In addition, in order to further improve the moldability, the melt flowability (MFR) of the polymer is increased, and in this case, the problem that the polymer becomes sticky and the polymer particles adhere to each other is suppressed. It is also possible to suppress silos and the like from being clogged with the coalesced particles.

  In order to solve the above-described problems of the invention, the present inventors have found that when a polymer such as a propylene-based block copolymer is used to increase the melt fluidity (MFR) of the polymer, the polymer tends to become sticky. In order to suppress the problem that the coalesced particles adhere to each other, and to find a method that can also suppress the blockage of silos due to the pressure bonding of the polymer particles, the properties of the soft polymer, the particle performance of the polymer particles, and the polymer particles As a result of extensive consideration of drying means, aeration, etc., select the component characteristics of the copolymer, identify the particle performance of the polymer particles, and adopt specific drying and aeration methods This has led to the solution of the problems of the invention and the creation of the present invention.

That is, the present invention increases the melt fluidity (MFR) of a polymer as much as possible in a soft polymer such as a propylene-based block copolymer, and the copolymer satisfies the following requirements and has fluidity and volatility. It is a polymer particle of a soft polymer characterized in that it has an excellent balance between the amount of the property component and moldability and powder storage.
a) In TREF (temperature rising elution fractionation), components that elute at 40 ° C. or lower are 23 wt% or higher or 30 wt% or higher b) The volatile content of the polymer particles is 100 wtppm or lower or 50 wtppm or lower c) The angle of repose is 20 to 55 °

  This invention is a basic invention, and for the basic invention (the inventions of the independent claims of claims 1 and 2), the accompanying embodiment inventions (each invention of the dependent claims) are polymers. The bending elastic modulus of the molded article of the particles is defined (Claim 3), the melting point and the bulk density of the polymer particles and the effective internal friction angle are specified (Claim 4), and the copolymer is defined (Claims 5 to 7). TREF component is specified (Claims 8 and 9), copolymer production method is defined (Claims 10 and 11), post-treatment step after the polymerization process is defined (Claim 12), and aeration is defined (Claim 13). It is each invention to do.

  Therefore, as described above, the basic invention is composed of a soft polymer such as a propylene-based block copolymer having a polymer melt fluidity (MFR) as high as possible. In the coalescence, soft polymer polymer particles satisfying the above requirements a) to c) and having excellent balance of particle fluidity and moldability and powder storage property, The new structure cannot be found in a small amount from the documents of the prior art.

In the above, the background of the creation of the present invention and the basic configuration and features of the invention have been described in general. Here, the overall configuration of the present invention will be summarized and summarized in the following [1]. ] To [13].
Here, the polymer particles in [1] and [2] are configured as basic inventions [1] and [2], and [3] The following inventions add requirements incidental to the basic invention, or The embodiment is shown, and the inventions [1] to [13] are collectively referred to as the present invention.

[1] Polymer particles of a soft polymer that satisfies the following requirements.
a) In TREF (temperature rising elution fractionation), the component eluting at 40 ° C. or less is 23 wt% or more b) The volatile content of the polymer particles is 100 wtppm or less c) The angle of repose of the polymer particles is 20 to 55 ° Is

[2] Polymer particles of a soft polymer that satisfies the following requirements.
a) In TREF (temperature rising elution fractionation), the component eluting at 40 ° C. or lower is 30 wt% or more b) The volatile content of the polymer particles is 50 wtppm or less c) The angle of repose of the polymer particles is 20 to 55 ° Is

[3] A polymer particle of a soft polymer, wherein a bending elastic modulus of a molded article using the polymer particle of [1] or “2” is 50 to 400 MPa.
[4] The melting point of the polymer particles is 115 to 145 ° C., the bulk density is 0.40 to 0.49 g / ml, and the effective internal friction angle is 20 to 55 °, [1 ] The polymer particle of the soft polymer in any one of [3].

[5] The soft polymer is a propylene-based random copolymer or propylene-based block copolymer containing a propylene unit and an ethylene unit or a C4 to C20 α-olefin unit. The polymer particle of the soft polymer in any one of "4".
[6] The soft polymer is a propylene-based random copolymer or propylene-based block copolymer containing a propylene unit, an ethylene unit, and a C4 to C20 α-olefin unit, [1] to The polymer particle of the soft polymer in any one of [4].
[7] The soft polymer polymer particle according to any one of [1] to [6], wherein the soft polymer is a propylene block copolymer polymerized with a metallocene catalyst.

[8] In TREF, the component eluting at 40 ° C. or less is a copolymer of propylene units and ethylene units or C4 to C20 α-olefin units, and the weight average molecular weight (Mw) is 150,000 to 250. The polymer particle of the soft polymer according to any one of [1] to [5] and [7], wherein
[9] In TREF, the component eluting at 40 ° C. or lower is a copolymer composed of propylene units, ethylene units, and C4 to C20 α-olefin units, and the weight average molecular weight (Mw) is 150,000 to 250. The soft polymer polymer particles according to any one of [1] to [4], [6], and [7], wherein

[10] A method for producing polymer particles of a soft polymer according to any one of [1] to [5], [7] and [8], wherein a propylene unit and an ethylene unit or a C4 to C20 α-olefin unit A polymer particle of a soft polymer, wherein a part or all of the polymerization step is gas phase polymerization when polymerizing a propylene random copolymer or propylene block copolymer Method.
[11] A method for producing polymer particles of a soft polymer according to any one of [1] to [4] and [6], [7] and [9], comprising propylene units, ethylene units and C4 to C20 When polymerizing a propylene-based random copolymer or propylene-based block copolymer containing an α-olefin unit, part or all of the polymerization step is gas phase polymerization. A method for producing coalesced particles.

[12] A method for producing a polymer particle of a soft polymer according to any one of [1] to [9], comprising a polymerization step and a post-treatment step after the polymerization step. A process for producing polymer particles of a soft polymer, characterized by comprising a step.
Step a): A step of drying the polymer powder at a temperature of 60 to 95 ° C. for 0.6 to 1.1 hours. Step b): A step of aeration of the polymer powder at a temperature of 25 to 95 ° C. for 6 to 50 hours.
[13] The method for producing polymer particles of a soft polymer according to [12], wherein the aeration is performed with a silo.

  In a soft polymer such as a propylene-based block copolymer, in order to shorten the cycle at the time of molding and to further improve the moldability, the melt fluidity (MFR) of the polymer is increased. It becomes easy to stick, and the problem that polymer particles adhere to each other can be suppressed, and further, blockage of silo or the like due to pressure bonding of the polymer particles can be suppressed.

It is the schematic diagram which showed one of the manufacturing apparatuses for manufacturing the polymer particle of this invention.

[I] Soft polymer polymer particles
(1) Basic rules The invention of claim 1 of the present invention is a polymer particle of a soft polymer, satisfies the following requirements, and is characterized by excellent balance of melt fluidity and particle fluidity and moldability. To do. (Examples 1 to 3 described later correspond to the invention.)
a) In TREF (temperature rising elution fractionation), the component eluting at 40 ° C. or less is 23 wt% or more. b) The volatile content of the polymer particles is 100 wtppm or less. c) The angle of repose of the polymer particles is 20 to 55 °. Another invention of the present invention, that is, the invention of claim 2, is a polymer particle of a soft polymer, characterized by satisfying the following requirements and having an excellent balance of melt fluidity, particle fluidity and moldability. . (Examples 1 and 2 described later correspond to the present invention.) A) In TREF (temperature rising elution fractionation), the component eluted at 40 ° C. or less is 30 wt% or more. B) Volatile content of polymer particles C) The angle of repose of the polymer particles is 20 to 55 °.

From the inventions of claims 1 and 2 described above, it is clear that soft polymer polymer particles satisfying the following conditions are also included in the invention.
a) In TREF (temperature rising elution fractionation), the component eluting at 40 ° C. or less is 23 wt% or more. b) The volatile content of the polymer particles is 100 wtppm or less and exceeds 50 wtppm. c) The angle of repose of the polymer particles is 20 to 55. In addition, from the inventions of claims 1 and 2 described above, it is clear that the polymer particles of the soft polymer that satisfy the following conditions are included in the invention.
a) In TREF (temperature rising elution fractionation), the component eluting at 40 ° C. or less is 23 wt% or more and less than 30 wt% b) The volatile content of the polymer particles is 100 wt ppm or less c) The angle of repose of the polymer particles is 20 Furthermore, it is apparent from the inventions of claims 1 and 2 that the polymer particles of a soft polymer satisfying the following conditions are included in the invention.
a) In TREF (temperature rising elution fractionation), the component eluting at 40 ° C. or less is 23 wt% or more and less than 30 wt% b) The volatile content of the polymer particles is 100 wtppm or less and exceeds 50 wtppm c) The angle of repose of the polymer particles is In the following, the polymer particles of the soft polymer of the present invention will be described in detail by taking, as an example, a case where the soft polymer is a propylene-based random copolymer or propylene-based block copolymer, which is a preferred embodiment. Will be described in detail and in detail.

(2) Regulation by TREF First, the polymer particles of the soft polymer of the present invention require that a) the component eluted at 40 ° C. or less in TREF is 23 wt% or more or 30 wt% or more.
TREF is a so-called temperature rising elution fractionation method, which is well known as a separation method based on the difference in crystallinity of polymer components. The polymer is completely dissolved in a solvent such as o-dichlorobenzene at a high temperature and packed into a column. The solution is allowed to flow down to the surface of the inert carrier, and then cooled to support a component such as a polymer to form a thin polymer layer, and then the temperature is raised continuously or stepwise. In this method, components having different properties are sequentially eluted and separated. In the low temperature stage, components with low crystallinity such as non-crystalline components and low crystallinity components in the polymer of interest elute, and components with higher crystallinity elute as the temperature rises.
Therefore, components that elute at 40 ° C. or lower in TREF are mainly amorphous components. That is, the component eluted at 40 ° C. or less in TREF is mainly referred to as a copolymer of propylene and ethylene and / or α-olefin in the propylene-based block copolymer (hereinafter referred to as “propylene-α-olefin copolymer”). ) Component.

In the polymer particles of the soft polymer of the present invention, the component that elutes at 40 ° C. or less in TREF is defined as 23 wt% or more, but 70 wt% or less is preferable. This range is preferable because the rigidity (flexural modulus) of the molded product is lowered and becomes flexible.
The proportion of the component eluted at 40 ° C. or less in TREF is preferably 25 wt% or more, 30 wt% or more, 35 wt% or more, and more preferably 40 wt% or more. In addition, the proportion of components eluting at 40 ° C. or less in TREF is more preferably 65 wt% or less.

  In the case of a propylene-based random copolymer, the amount of the component eluted at 40 ° C. or less in TREF can be controlled by, for example, the content of α-olefin (including ethylene). In the case of a propylene-based block copolymer, for example, the ratio of the propylene-α-olefin copolymer component to the total of the propylene polymer component and the propylene-α-olefin (including ethylene) copolymer component, propylene -It is controllable by content of the alpha olefin (including ethylene) in the alpha olefin copolymer component. For example, in the case of a propylene-ethylene copolymer, as the ethylene content increases from about 1 wt% to about 50 wt%, the amount of components that elute at 40 ° C. or less increases, and as a result, flexibility increases.

(3) TREF measuring method In this invention, specifically, it measures as follows. A sample is dissolved in o-dichlorobenzene (containing 0.5 mg / ml BHT) at 140 ° C. to obtain a solution. This is introduced into a 140 ° C. TREF column, cooled to 100 ° C. at a rate of 8 ° C./min, subsequently cooled to −15 ° C. at a rate of 4 ° C./min, and held for 60 minutes. Then, o-dichlorobenzene (containing 0.5 mg / ml BHT) as a solvent is passed through the column at a flow rate of 1 ml / min, and the components dissolved in o-dichlorobenzene at −15 ° C. are eluted in the TREF column for 10 minutes. Next, the column is linearly heated to 140 ° C. at a temperature rising rate of 100 ° C./hour to perform elution separation.

  An amorphous component having a low elution temperature is rich in flexibility, while a crystalline component having a high elution temperature contributes to improvement in rigidity and heat resistance. In the elution curve (dwt% / dT curve with respect to temperature) of the propylene-based block copolymer in the present invention, a crystalline propylene homopolymer component, propylene and ethylene and / or C4 to C20 α A copolymer component of a propylene polymer component, such as a copolymer component with an olefin, and a low crystalline or non-crystalline propylene and ethylene and / or a C4-C20 α-olefin; From the difference, it is observed as a component eluting at different temperatures. That is, the propylene homopolymer or the copolymer of propylene and ethylene and / or C4 to C20 α-olefin obtained in the first step is obtained on the high temperature side, whereas the first step is obtained in the second step. Higher ethylene and / or C4-C20 alpha-olefin content copolymers with propylene are observed on the low temperature side due to low or non-crystalline nature.

(4) Limitation by Volatile Content The polymer particles of the soft polymer of the present invention are then b) volatile content (volatile component) of 50 wt.
The requirement is ppm or less or 100 wtppm or less. Preferably it is 40 wtppm or less, More preferably, it is 30 wtppm or less.
The amount of volatile content of the polymer particles of the soft polymer can be controlled by, for example, the temperature and time of step a) and step b) described later.
When the soft polymer is a propylene-based block copolymer and the propylene-α-olefin copolymer component is a propylene-ethylene random copolymer, the volatile content (volatile component) of the polymer particles is preferably It is 50 wtppm or less, More preferably, it is 40 wtppm or less, More preferably, it is 30 wtppm or less.
When the soft polymer is a propylene-based block copolymer and the propylene-α-olefin copolymer component is a propylene-ethylene-butene random copolymer, since the boiling point of butene is high, a larger amount of volatile matter The amount can be tolerated, and the volatile content (volatile component) of the polymer particles is preferably 100 wtppm or less, more preferably 80 wtppm or less, and even more preferably 50 wtppm or less.

(5) Method for measuring residual volatile content contained in polymer particles In the present invention, specifically, the measurement is performed as follows.
Measuring instrument: Autosampler: Headspace Sampler Turbo Martrix 40 manufactured by Perkin Elmer
Gas chromatograph: CG-2025 manufactured by Shimadzu Corporation
Column: Phenomenex ZB-624
The sample was heated with an autosampler at a temperature of 150 ° C. for 30 minutes to volatilize residual volatile components in the polymer particles, and components and amounts thereof were measured with a gas chromatograph connected to the autosampler.

(6) Regulation by angle of repose The polymer particles of the soft polymer of the present invention further require c) angle of repose of 20 to 55 °.
The above-mentioned range is necessary for the polymer of the soft polymer of the present invention in order not to impair the flow at the time of extraction even when stacked on a silo or the like.
The angle of repose is the maximum angle with respect to the horizontal of the stacked slope in a state in which stability is maintained without spontaneously collapsing when the powder (particles) are stacked. It is determined by the size of the particles and the roundness and shape of the corners of the particles, and is understood as the so-called “smoothness”.

In other words, the angle of repose is one of the general fluidity indices of particles (powder). The angle of repose is when the free surface of the powder layer is in a critical stress state, and the surface of the powder layer is relative to the horizontal plane. It is the angle to be made. It can be said that the angle of repose is an angle formed by the horizontal plate and the slope of the conical deposition obtained by continuously dropping the powder from one point in the air onto the horizontal plate.
Accordingly, a small angle of repose means good fluidity. Therefore, the upper limit of the angle of repose of the present invention is 55 ° or less, preferably 45 ° or less, and more preferably 4 °.
0 ° or less. On the other hand, if the angle of repose is too small, the polymer will flow excessively, and the amount of flow when extracting the polymer will be excessive, so the lower limit of the angle of repose is 2
It is 0 ° or more, more preferably 25 ° or more, and further preferably 30 ° or more.

(7) Measurement of angle of repose There are an injection method, a discharge method, and a gradient method for the measurement of the angle of repose. In the present invention, a gradient method that makes it easy to confirm the flow state of polymer particles can be used. . In the present invention, the angle of repose of the tilt at the time of rotation is measured using a repose angle measuring instrument of the three-wheeled cylinder rotation method manufactured by Tsutsui Rikagaku Co., Ltd.

(8) Properties of angle of repose The angle of repose varies depending on physical properties such as crystallinity and softness of the surface and the interior of the polymer, weight, overall shape, and external and internal forms.
In particular, the crystallinity on the surface and inside can be controlled by changing the polymerization conditions at each stage when multistage polymerization is used. For example, by increasing the polymerization ratio of non- (low) crystalline components, decreasing the molecular weight, and increasing comonomer such as ethylene, the angle of repose increases and the flowability of particles decreases.

In particular, in the case of a propylene-based block copolymer, the angle of repose is small and fluidity can be improved when the amount of ethylene in the comonomer of propylene and ethylene-α-olefin copolymer is between 10 wt% and 20 wt%, but it exceeds 20 wt%. In the range of 50 wt%, the angle of repose increases and the fluidity decreases.
In addition, the shape of the polymer particles is affected by the shape of the original catalyst particles as called the replica rule. Therefore, the angle of repose can be controlled by appropriately selecting the type of catalyst, the shape of carrier used for the catalyst, and the strength distribution thereof.

(9) Bulk density of polymer particles
In the present invention, as a secondary regulation, the bulk density of the polymer particles is regulated, and the bulk density (BD) of the polymer particles is 0.40 to 0.49 g / ml.
The polymer particles of the soft polymer of the present invention preferably have a bulk density of 0.40 g / ml or more. More preferably, it is 0.42 g / ml or more, More preferably, it is 0.45 g / ml or more.
If the bulk density of the particles is too small, the binder phenomenon is promoted due to an increase in contact points between particles and an increase in particle adhesion.
On the other hand, if the bulk density is too high, it means that the polymer particles are heavy when they are piled up with a silo, and the large self-weight promotes the binder phenomenon of the polymer particles of the soft polymer. Also, when one of the polymer particles is viewed, the crystalline component is in a state of being filled with a non- (low) crystalline component, which causes subsequent bleeding out. Therefore, the upper limit of the bulk density is preferably 0.49 g / ml.

(10) Bulk density (BD) measurement method The bulk density of polymer particles is measured according to ASTM D1895-69.

(11) Effective internal friction angle
In the present invention, the effective internal friction angle of the polymer particles is defined as a secondary rule, and the effective internal friction angle of the polymer particles is set to 20 to 55 °.
When stress is applied to a powder layer in which powders such as polymer particles are stacked, the powder layer eventually collapses, but normal stress and shear stress at the limit state where this collapse occurs are plotted on the stress plane. The curve obtained in this way is called the powder disintegration curve. This powder disintegration curve is an important mechanical property of powder in order to quantitatively discuss how much stress is applied to the powder layer to cause the powder layer to collapse or to flow.

For powders such as polymer particles used in the present invention that are likely to have high adhesion, the powder disintegration curve is a convex curve, but the slope of the powder disintegration curve, that is, the effective internal friction angle is Different values depending on the normal stress. Therefore, in order to evaluate the properties of highly adherent powder that bridging occurs in the container and is easily clogged, the effective internal friction angle is a measurement method that can appropriately evaluate the behavior in a consolidated state. It can be said that it is useful (Introductory "Particle and Powder Engineering" Soichiro Ichiro / Michitaka Suzuki / Ryoteru Kanda, published August 31, 2011 (Nikkan Kogyo Shimbun) p.16.
1-164 description).

  Storage blockage is related to the mechanical behavior of the powder. It is known that the behavior can be estimated by the shear slip phenomenon in the powder, that is, the frictional characteristics of the powder. In particular, the effective internal friction angle obtained by the Jenike method focusing on the frictional characteristics of powder is very effective in grasping the fluidity limit in a tank shaped like a vertical cylindrical dryer (5th revised edition).・ Handbook of chemical engineering ・ March 18, 1988 (Maruzen Publishing) p.250-253 description).

The polymer particles of the present invention preferably have an effective internal friction angle of 20 ° or more, more preferably 35 ° or more, as measured by the Jenike method shear stress measurement at room temperature.
5 ° or less.
When the effective internal friction angle is 20 ° or more, the powder flowability is small, and thus the effect of introducing the apparatus is not reduced. Further, when the effective internal friction angle is 55 ° or less, the adhesion between the powders becomes appropriate, so that the polymer particles can be more easily extracted continuously from the discharge port.

(12) Method for Measuring Effective Internal Friction Angle The method for measuring the effective internal friction angle is detailed in the above-mentioned document. In this specification, a powder rheometer (manufactured by Malvern, FT-4) is used, and the preload condition is 6 KPa. At room temperature, a shear test was conducted by applying a preload to the powder layer, a Mole circle corresponding to the fracture envelope obtained at this time was drawn, and the slope of the straight line in contact with the Mole circle was obtained as the effective internal friction angle. is there.
A shear test was performed by preloading the powder layer at room temperature using the powder rheometer described above. A Mole circle corresponding to the fracture envelope obtained at this time was drawn, and the gradient of the straight line in contact with the Mole circle was taken as the effective internal friction angle.

(13) Average particle size
The polymer particles of the soft polymer of the present invention preferably have an average particle size of 700 to 3,000 μm. When the average particle diameter is within this range, the particles can be prevented from sticking and bridging, and even when they are stacked and stored in a silo or the like, they can be stably extracted using piping.
The average particle diameter is preferably 700 μm or more, more preferably 800 μm or more, and still more preferably 900 μm or more. The average particle diameter is preferably 3,000 μm or less, more preferably 2,800 μm or less, still more preferably 2,500 μm or less, and still more preferably 2,000 μm or less.

  The average particle size of the polymer powder can be controlled by the particle size of the catalyst used for polymerization and the polymerization amount. The average particle size of the polymer powder increases as the catalyst particle size increases. In the case of a supported catalyst, the larger the particle size of the carrier used for the catalyst, the larger the particle size of the catalyst, and consequently the larger the average particle size of the polymer powder.

(14) Measurement of average particle diameter For measurement of the average particle diameter of the polymer powder, a vibrating sieve particle size measuring device (aperture 100 μm, 15
Vibrating for 10 minutes or more with a shaker of 0 μm, 212 μm, 350 μm, 500 μm, 710 μm, 850 μm, 1,000 μm, 1,180 μm, 1,400 μm, 1,700 μm, 2,000 μm, 2,800 μm, 3,000 μm A method of classifying and measuring and plotting the result on log-normal probability paper and obtaining a 50% particle diameter as an average particle diameter) or a robot shifter that automatically performs these may be used.

(15) Amount of fine powder particles In the polymer particles of the soft polymer of the present invention, the amount of fine particles (fine powder particles) having a particle diameter of about 200 μm or less is preferably 1.0 wt% or less. When the amount of fine powder particles is 1.0 wt% or less, even if the powder is consolidated when stored in a silo or the like, it can be stably extracted using piping. A small amount of fine particles also means a narrow particle size distribution. The amount of fine powder particles is expressed as a percentage of the weight of the whole sample under a sieve having an opening of 212 μm.
When the amount of fine powder particles is 1.0 wt% or less, fine powder particles do not enter between the polymer particles having an average particle size, and the contact between the polymers does not increase, so-called binder phenomenon does not occur. Adhesion between the polymer particles is not promoted. Therefore, the amount of fine powder particles is preferably 1.0 wt% or less, more preferably 0.9 wt% or less, and still more preferably 0.8 wt% or less.

  The amount of fine powder particles is often generated when the catalyst particles are disintegrated at the initial stage of polymerization. Accordingly, the amount can be reduced by appropriately selecting catalyst particles or carrier particles having an appropriate strength. Moreover, it produces | generates by the friction with a polymer particle, a polymerization tank wall, and a stirring blade between polymer particles. Therefore, the amount can be reduced by selecting an appropriate polymerization method. Therefore, control of residence time distribution is also included in the polymerization method.

In addition, the small amount of fine particles as in the present invention also means that the particle size distribution is narrow. The particle size distribution of the polymer particles of the soft polymer of the present invention is preferably in the range of 1 to 5 in terms of n value when expressed by rosin Ramler distribution.
In order to obtain the polymer particles having a particle size distribution of the present invention, it is preferable to use a plug flow type polymerization method using a horizontal stirring device with a stirring blade during the polymerization.

[II] Other regulations for polymer particles of soft polymer
(1) Flexural modulus In the present invention, as a secondary regulation, the flexural modulus of a molded article using polymer particles is regulated to 50 to 400 MPa.
Flexural modulus is an index of flexibility. The smaller the value, the better the flexibility of the molded product. For example, when used as a container lid, a strong force is not required when opening the lid. Moreover, the possibility that the lid will break can be reduced.

Therefore, when the flexural modulus is 400 MPa or less, flexibility as a polymer is maintained. Therefore, the polymer of the present invention is a polymer of 400 MPa or less, preferably 300 MPa or less, more preferably 200 MPa or less.
Further, when the elastic modulus exceeds 50 MPa, “the stickiness of the non-crystalline component of the polymer increases the stickiness of the polymer particles, and then any method is used to cause silo blockage. Does not arise. Therefore, the flexural modulus of the molded article using the polymer particles needs to be preferably 50 MPa or more, more preferably 70 MPa or more, and still more preferably 100 MPa or more.

The flexural modulus can be controlled by the amount of α-olefin in the case of a propylene-based random copolymer and by the polymerization ratio of the ethylene-α-olefin copolymer component in the case of a propylene-based block copolymer. Moreover, it is controllable by the comonomer content in the ethylene-alpha-olefin copolymer of a block copolymer.
For example, in the case of an ethylene-propylene copolymer, the flexural modulus decreases and the flexibility increases as the ethylene content increases from about 10 wt% to about 50 wt%.
The soft polymer of the present invention is not only a propylene block copolymer, but also a kind of α-olefin selected from ethylene such as a propylene random copolymer and an ethylene / α-olefin copolymer and C3-C20 α-olefin. It may be a single polymer of olefin or a copolymer between two or more α-olefins.
In the present invention, the “soft polymer” means, for example, a polymer having a flexural modulus of about 800 MPa or less.

(2) Method of measuring flexural modulus After molding, a test piece was molded and left in a temperature-controlled room adjusted to room temperature 23 ° C. and relative humidity 50% after molding for 24 hours, and then in JIS K-7171 (ISO178). Obtained in compliance.

(3) Melting point (Tm)
The present invention defines the melting point of the polymer particles as a secondary rule. The melting point of the soft polymer of the present invention is suitably in the range of 115 to 145 ° C. The amount of non- (low) crystalline component is increased.
This range is preferable because the rigidity (flexural modulus) of the polymer is lowered and becomes flexible. Therefore, the melting point of the soft polymer of the present invention is in the range of 115 to 145 ° C. When the temperature is 145 ° C. or lower, the flexibility of the soft polymer of the present invention is maintained, and when the temperature is 115 ° C. or higher, the polymer is not melted by the polymerization heat to prevent production. Preferably it is 140 degrees C or less, Preferably it is 120 degrees C or more.

  The melting point depends on the amount of α-olefin (including ethylene) in the case of a propylene random copolymer, and in the case of a propylene block copolymer, the melting point of the α-olefin (including ethylene) in the crystalline component. It can be controlled by the amount.

(4) Melting point measurement method Using DSC (DSC6200R) manufactured by Seiko Co., Ltd., taking 5.0 mg of sample, holding it at 200 ° C. for 5 minutes, crystallizing to 40 ° C. at a rate of 10 ° C./min, then 10 ° C. The melting peak temperature when melted at a rate of temperature increase per minute was defined as Tm (unit: ° C.).

[III] Regulation as copolymer The polymer particles of the soft polymer of the present invention are not only propylene block copolymers, but also ethylene such as propylene random copolymers and ethylene / α-olefin copolymers, and C3. It may be a single polymer of one α-olefin selected from —C20 α-olefins or a copolymer between two or more α-olefins.
As a secondary definition, it is specified as a copolymer. Specifically, it is a random copolymer or block copolymer of propylene and ethylene and / or a C4 to C20 α-olefin. The coalesced particle is a propylene block copolymer polymerized with a metallocene catalyst, and the component eluting at 40 ° C. or lower in TREF is a copolymer of propylene and ethylene and / or α-olefin, The weight average molecular weight (Mw) is assumed to be 150,000-250,000.

  As an example of the polymer particles of the soft polymer of the present invention, in the first step, propylene homopolymerization or propylene random polymerization of propylene and ethylene and / or C4 to C20 α-olefin is performed, and in the second step, It is preferred that the copolymerization containing propylene and ethylene in a higher content than the first step and / or C4 to C20 α-olefin is continuously carried out, and ethylene produced in two or more polymerization reactors and Examples thereof include a random copolymer of C4 to C20 α-olefin and propylene, and a propylene-based block copolymer.

The component eluting at 40 ° C. or lower in TREF is a copolymer of propylene and ethylene and / or α-olefin, and its weight average molecular weight (Mw) is 150,000-25.
The component that is 0.0000 and elutes at 40 ° C. or less with TREF is a non- (low) crystalline copolymer component.
When Mw is large, that is, the flowability (MFR) at the time of melting of the soft polymer does not become small, and the moldability deteriorates. For example, problems such as a longer molding cycle and higher injection pressure occur. In addition, there is a concern that the rubber component will not be finely dispersed in the molded body and the appearance will deteriorate. Therefore, the upper limit value of Mw is 250,000.

In addition, when Mw is small, the MFR of the soft polymer becomes too large, so that not only molding defects occur, but also the tensile properties of the molded body are lowered, resulting in problems in physical properties such as reduced impact strength.
Therefore, when the non- (low) crystalline copolymer component according to the present invention is mainly used for injection molding, the lower limit value of Mw is 150,000 or more, preferably 160,000 or more, more preferably 170,000 or more.

  The method for controlling the molecular weight of the non- (low) crystalline copolymer component can be controlled by using hydrogen as a molecular weight modifier. The amount can be determined by predicting the dependence of the specific metallocene complex on the ultimate molecular weight (molecular weight that can be generated by chain transfer other than hydrogen), the rate of chain transfer reaction by hydrogen, reaction temperature, pressure, and comonomer concentration. .

[IV] Production by metallocene catalyst (1) Metallocene catalyst For production of the polymer of the present invention, it is desirable to use a metallocene catalyst. When manufactured with a Ziegler-Natta catalyst, low molecular weight components increase, and therefore it is difficult to suppress the adhesion of the polymer powder within the temperature setting range of step a) and step b) described later.
The type of the metallocene-based catalyst is not particularly limited as long as it can produce a copolymer having the performance of the present invention. However, in order to satisfy the requirements of the present invention, for example, the following components ( It is preferable to use a metallocene catalyst comprising A), (B), and component (C) used as necessary.

  Component (A): at least one metallocene transition metal compound selected from transition metal compounds represented by general formula (1)

(In the formula, A and A ′ are conjugated five-membered ring ligands that may have a substituent, Q is a binding group that bridges two conjugated five-membered ring ligands at an arbitrary position, X And Y is a σ covalent bond auxiliary ligand that reacts with a cocatalyst to develop olefin polymerization ability, M is a transition metal of Group 4 of the periodic table, and titanium, zirconium, and hafnium are preferred.

Component (B): at least one solid component selected from the following (b-1) to (b-4) (b-1) a particulate carrier (b-2) on which an organic aluminum oxy compound is supported (A) component (A ) An ionic compound capable of converting component (A) into a cation by reacting with) or a particulate carrier carrying a Lewis acid (b-3) a solid acid particulate (b-4) an ion-exchange layered silicate Component (C): Organoaluminum compound

(2) Each component (i) Component (A)
As the component (A), at least one metallocene transition metal compound selected from the transition metal compounds represented by the above general formula (1) can be used.
In the above general formula, the conjugated five-membered ring ligand represented by A and A ′ is a cyclopentadienyl group derivative which may have a substituent. When it has a substituent, examples of the substituent include a hydrocarbon group having 1 to 30 carbon atoms (which may contain a heteroatom such as halogen, silicon, oxygen, sulfur, etc.), and this hydrocarbon. Even if the group is bonded to the cyclopentadienyl group as a monovalent group, when two or more of them are present, two of them are bonded to each other at the other end (ω-end) to form one cyclopentadienyl group. A ring may be formed together with the part. Other examples of the substituent forming this ring include an indenyl group, a fluorenyl group, or a hydroazurenyl group, and these groups may further have a substituent, and among them, an indenyl group or a hydroazurenyl group. Is preferred.

Q is preferably a methylene group, an ethylene group, a silylene group, a germylene group, a group in which these are substituted with a hydrocarbon group, or a silafluorene group.
The auxiliary ligands X and Y are those that react with a cocatalyst such as component (B) to produce an active metallocene having olefin polymerization ability, each of which is a hydrogen atom, a halogen atom, a hydrocarbon group, or oxygen. And hydrocarbon groups optionally having heteroatoms such as nitrogen and silicon. Among these, a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom is preferable.
M is preferably titanium, zirconium or hafnium. In particular, zirconium and hafnium are preferable.

Further, among the transition metal compounds, those in which stereoregular polymerization of propylene proceeds and the obtained propylene polymer has a high molecular weight are preferable. Specifically, JP-A-1-301
No. 704, JP-A-4-21694, JP-A-6-1000057, JP-T 2002-535339, JP-A-6-239914, JP-A-10-226.
Preferred examples include transition metal compounds described in JP-A No. 712, JP-A-3-193966, JP-T-2001-504824, and the like.

(Ii) Component (B)
As the component (B), at least one solid component selected from the components (b-1) to (b-4) described above is used. Each of these components is a known component, and can be appropriately selected from known technologies and used. Specific examples and manufacturing methods thereof are described in JP-A-200.
Detailed examples are disclosed in JP-A-2-284808, JP-A-2002-53609, JP-A-2002-69116, and the like.
Here, as the particulate carrier used for the component (b-1) and the component (b-2), inorganic oxides such as silica, alumina, magnesia, silica alumina, silica magnesia, magnesium chloride, magnesium oxychloride, chloride Examples thereof include inorganic halides such as aluminum and lanthanum chloride, and porous organic carriers such as polypropylene, polyethylene, polystyrene, styrene divinyl benzene copolymer, and acrylic acid copolymer.

The fine particle carrier used for the component (b-1) and the component (b-2) has an average particle size measured by a laser particle size measurement method of preferably 25 to 200 μm, and more preferably 25 to 150 μm.
Further, as a non-limiting specific example of the component (B), a particulate carrier on which methylalumoxane, isobutylalumoxane, methylisobutylalumoxane, aluminum butylboronate tetraisobutyl, etc. are supported as the component (b-1). As component (b-2), triphenylborane, tris (3,5-difluorophenyl) borane, tris (pentafluorophenyl) borane, triphenylcarbonium tetrakis (pentafluorophenyl) borate, N, N-dimethyl As a component (b-3), a particulate carrier carrying anilinium tetrakis (pentafluorophenyl) borate as a component (b-3) is treated with alumina, silica alumina, magnesium chloride, a fluorine compound, and then fired on silica alumina, pentafluorophenol and Diethyl zinc Silica etc. which supported the same product after reacting with any organometallic compound and water, as a component (b-4), montmorillonite, zakonite, beidellite, nontronite, saponite, hectorite, steven in clay minerals Examples thereof include ion-exchange layered silicates such as smectite group such as site, bentonite and teniolite, vermiculite group and mica group. These may form a mixed layer.
Particularly preferred among the above components (B) is the ion-exchange layered silicate of component (b-4), and more preferred are chemical treatments such as acid treatment, alkali treatment, salt treatment, and organic matter treatment. It is an ion exchange layered silicate applied.

(Iii) Component (C)
Examples of the component (C) organoaluminum compound used as necessary are those represented by the general formula AlR _a X _3-a (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is hydrogen, halogen, alkoxy) Group, a is a number of 0 <a ≦ 3) trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, or halogen or alkoxy containing diethylaluminum monochloride, diethylaluminum monomethoxide, etc. Alkyl aluminum. In addition, aluminoxanes such as methylaluminoxane can also be used. Of these, trialkylaluminum is particularly preferred.

(3) Formation of catalyst Component (A), component (B) and, if necessary, component (C) are brought into contact to form a catalyst. The contact method is not particularly limited, but the contact can be made in the following order. Moreover, this contact may be performed not only at the time of catalyst preparation but also at the time of prepolymerization with olefin or at the time of polymerization of olefin.
1) Contact component (A) and component (B) 2) Add component (C) after contacting component (A) and component (B) 3) Contact component (A) and component (C) 4) Add component (B) after bringing component (B) and component (C) into contact. In addition, three components may be contacted at the same time.

The amount of components (A), (B) and (C) used in the present invention is arbitrary. For example, the amount of component (A) used relative to component (B) is preferably in the range of 0.1 μmol to 500 μmol, particularly preferably 0.5 μmol to 100 μmol, relative to 1 g of component (B). The amount of component (C) used relative to component (B) is preferably in the range of 0 to 100 mmol, particularly preferably 0.005 mmol to 50 mmol, with respect to 1 g of component (B). Therefore, the amount of component (C) relative to component (A) is in the range of 0 to 10 ⁶ , preferably 0.02 to 10 ⁵ , particularly preferably 0.2 to ^{10 4} in terms of the molar ratio of transition metal. Since (C) is an optional component, 0 was included.

(4) Prepolymerization The catalyst of the present invention is preferably subjected to a prepolymerization treatment comprising a small amount of polymerization by previously contacting an olefin. The olefin to be used is not particularly limited, but ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, styrene and the like can be used. These can be used, and these may be used alone or as a mixture of two or more with other α-olefins. Among these, it is particularly preferable to use propylene. The olefin can be supplied by any method such as a supply method for maintaining the olefin at a constant speed or in a constant pressure state, a combination thereof, or a stepwise change.

  The prepolymerization temperature and time are not particularly limited, but are preferably in the range of −20 ° C. to 100 ° C. and 5 minutes to 24 hours, respectively. The amount of prepolymerization is preferably 0.01 to 100, more preferably 0.1 to 50 with respect to the component (B). In general, the prepolymerization treatment is preferably performed with stirring, and an inert solvent can also be present at that time. Inert solvents used in the prepolymerization treatment are inert solvents that do not significantly affect the polymerization reaction, such as liquid saturated hydrocarbons such as hexane, heptane, octane, decane, dodecane and liquid paraffin, and silicon oil having a dimethylpolysiloxane structure. It is an active solvent. These inert solvents may be either one kind of single solvent or two or more kinds of mixed solvents. When these inert solvents are used, it is preferable to use them after removing impurities such as water and sulfur compounds that adversely affect the polymerization.

The prepolymerization treatment may be performed a plurality of times, and the monomers used at this time may be the same or different. Moreover, it can wash | clean with inert solvents, such as hexane and a heptane, after a prepolymerization process. After completion of the prepolymerization, the catalyst can be used as it is, depending on the usage form of the catalyst. However, if necessary, drying can be performed.
Furthermore, a fluidity modifier for a catalyst selected from polymers such as polyethylene, polypropylene and polystyrene, and inorganic oxide solids such as silica and titania can be coexisted during or after the contact of the above components. It is.

[V] Polymerization of polymer powder (1) Polymerization format As the polymerization format, a batch method, a continuous method, or the like can be adopted for each of the first step and the second step. As an example of the present invention, a two-stage polymerization consisting of a first step and a second step is performed, but in some cases, each step can be further divided. From the viewpoint of production efficiency, two-stage polymerization consisting of the first step and the second step is preferred.

(2) Polymerization method In the present invention, when the first step portion is performed by so-called slurry polymerization in which polymerization is performed in an inert solvent, the melting point of the component (A) (the polymer in the first step) is relatively low. In addition, since the amount of eluted components in the solvent increases, industrially stable production becomes difficult. In addition, since the separation and recovery operation of the eluted components is also necessary, the manufacturing cost increases and it is not suitable for industrial production. Also, if the first step portion is carried out by so-called bulk polymerization in which polymerization is performed in liquid propylene, there is a concern about the dissolution of the polymer during the production of the low melting point polymer, so the polymerization temperature cannot be raised to an industrial level. Since it is difficult to control the activity, the catalyst efficiency in the first step may be too high. For this reason, it becomes impossible to produce a propylene-ethylene random block copolymer having a high proportion of the component (B) produced in the second step. From such a viewpoint, in the present invention, it is most preferable to perform the first step by gas phase polymerization.

Furthermore, it is desirable to employ gas phase polymerization in the production of the second step. In the second step, a propylene-ethylene and / or α-olefin random copolymer component is produced as a rubber component, but if a liquid such as a solvent is present, the rubber component is eluted into the solvent.
Therefore, in the production of the component (B) (polymer in the second step) of the present invention, the gas phase polymerization method is preferable, and in particular, a polymer having a large proportion of the component (B) as in the present invention is produced. For this, a gas phase polymerization method is preferred. More preferably, it is desirable to use a gas phase polymerization method with mechanical stirring.

  Further, in the second step, when the propylene-ethylene-butene random copolymer component is polymerized, the gas phase polymerization is preferably performed because the rubber component is not easily eluted into the solvent, and more preferably mechanical. It is desirable to use a gas phase polymerization method with stirring.

(3) Polymerization reactor In the present invention, the form of the reactor is not limited as long as it is a gas phase polymerization process with mechanical stirring, and it can be used in a vertical reactor, a horizontal reactor, or other forms. can do. More preferably, the stirring device is a horizontal reactor having a horizontal stirring shaft.

  The catalyst particles supplied to the upstream end of the horizontal reactor gradually grow into polymer particles by the polymerization reaction. When polymerization is performed in a horizontal reactor, these particles progress along the axial direction of the reactor while gradually growing due to the two forces of formation of polypropylene by polymerization and mechanical stirring. Therefore, particles having a uniform growth degree, that is, a residence time, are arranged with time from the upstream end to the downstream end of the reactor. Thus, in the horizontal reactor, the flow pattern is a piston flow type, and the residence time distribution is narrowed to the same extent as when several complete mixing tanks are arranged in series. This is an excellent feature not found in other polymerization reactors, and a single reactor can easily achieve a degree of solid mixing equivalent to two, three or more reactors. This is economically advantageous.

(4) Heat removal in gas phase polymerization In the gas phase polymerization, the heat removal method of the polymerization heat is not particularly limited, and the heat removal by the heat of vaporization of the cooling gas and liquefied propylene can be used.
More preferably, a heat removal method using liquefied propylene is desirable. Since the liquefied propylene impregnates the polymer powder, a heat removal effect is obtained even in the polymer powder, and greatly contributes to maintaining the properties of the polymer powder. Due to this effect, the heat removal method by the heat of vaporization of liquefied propylene is very effective for expanding the production range of the propylene-ethylene random block copolymer.

(5) First Step For example, in the copolymerization of propylene and ethylene, the first step feeds the metallocene catalyst from the upstream portion of the reactor, and fills the gas phase portion of the reactor with propylene and ethylene gas. In this step, the polymer powder phase is stirred and mixed by a stirring blade, and propylene and ethylene are copolymerized to produce component (A) (the polymer produced in the first step).

The higher the ethylene content [E] A in the component (A), the lower the melting point (Tm), and the lower [E] A, the higher Tm. Therefore, in order to satisfy Tm within the prescribed range of the present invention, [E] A and the relationship between them may be grasped and [E] A may be controlled to be in a predetermined range.
The relationship between the amount ratio of propylene and ethylene supplied to the polymerization tank and the ethylene content in the resulting propylene-ethylene random copolymer varies depending on the type of metallocene catalyst used, but the feed amount molar ratio is adjusted as appropriate. Thus, the component (A) having an arbitrary ethylene content [E] A can be produced. For example, when [E] A is controlled to 1 to 6 wt%, the molar ratio of ethylene to propylene is in the range of 0.001 to 0.3, preferably in the range of 0.025 to 0.25. It ’s fine.

(6) Second Step In the present invention, the polymerization temperature in the second step is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, still more preferably 55 ° C. or higher, while the upper limit of the polymerization temperature is 85 ° C. or lower. More preferably, it is 80 degrees C or less, More preferably, it is 75 degrees C or less. If it is 40 ° or more, the polymerization rate does not significantly decrease and the productivity does not deteriorate. Below 85 ° C., the polymerization temperature does not increase, the component (B) (the copolymer produced in the second step) does not bleed on the surface of the polymer powder, and the adhesion of the polymer powder does not increase. Therefore, the polymer powder does not adhere to the polymer powder, the stirring blade, or the wall surface of the reactor, and the stirring behavior becomes normal. Furthermore, it does not adhere to the storage tank or the transport pipe, and the blockage does not occur.

The proportion of component (B) produced in the second step is generally controlled using an electron donor compound as an activity inhibitor. Examples of the activity inhibitor include carbon monoxide, carbon dioxide, oxygen, carbonyl sulfide, and ammonia.
Further, an electron donor compound (electron donating compound) having a large molecular weight such as methanol, ethanol, isopropyl alcohol, acetone, or methyl acetate may be used.
In addition, the polymerization activity can be controlled by controlling the residence time in the second step and controlling the monomer pressure. However, a method using an activity inhibitor is the simplest control method.

Furthermore, hydrogen is used as a molecular weight regulator and in an auxiliary range of 1.0 × 10 ⁻⁴ or more and 1.0 × 10 ⁻² or less in terms of molar ratio with respect to ethylene for the purpose of improving the activity. be able to.
Therefore, hydrogen is preferably used in a molar ratio with respect to ethylene of 5.0 × 10 ⁻⁴ or more. Moreover, regarding an upper limit, it is good to use at 2.0 * 10 <^-3> or less, Preferably it is 1.0 * 10 <^-3> or less.
If it is more than the above lower limit, the hydrogen concentration is not too low and measurement is possible. In the catalyst described in this specification, the catalytic activity increases as the hydrogen concentration increases. On the other hand, if the amount is less than the above upper limit, the activity does not become too high, the removal of the polymerization heat cannot catch up, and there is no possibility that the bleeding of the amorphous component becomes redundant.

  The higher the ethylene content [E] B in the component (B), the lower the melting point (Tm), and the lower [E] B, the higher Tm. Therefore, in order to satisfy Tm within the specified range of the present invention, [E] B and the relationship between them may be grasped and [E] B may be controlled to be in a predetermined range. The relationship between the amount ratio of propylene and ethylene supplied to the polymerization tank and the ethylene content in the resulting propylene-ethylene random copolymer varies depending on the type of metallocene catalyst used, but the supply amount and molar ratio are adjusted appropriately. By doing, the component (B) which has arbitrary ethylene content [E] B can be manufactured. For example, when [E] B is controlled to 11 to 20 wt%, the molar ratio of ethylene to propylene should be in the range of 0.1 to 0.8, preferably in the range of 0.2 to 0.7. It ’s fine.

When a propylene-ethylene-butene random copolymer is produced as the component (B), the higher the butene content [B] B in the component (B) is, the higher the melting point (Tm). Tm increases as [B] B decreases.
Therefore, in order to satisfy Tm within the prescribed range of the present invention, [B] B and the relationship between them may be grasped and [B] B may be controlled so as to fall within a predetermined range.
The relationship between the amount ratio of propylene and butene supplied to the polymerization tank and the butene content in the resulting propylene-ethylene-butene random copolymer varies depending on the type of metallocene catalyst used, but the amount supplied and the molar ratio are appropriately selected. The component (B) having an arbitrary butene content [B] B can be produced by adjusting.
For example, when [B] B is controlled to 20 to 30 wt%, the molar ratio of butene to propylene should be in the range of 0.2 to 1.6, preferably in the range of 0.4 to 1.4. It ’s fine.

  In the catalyst described in the present specification, the catalyst activity increases as the ethylene concentration increases, and the Tm of the polymer powder decreases. Below the range described in paragraph 0093, the ethylene concentration is too low, the catalytic activity is remarkably lowered, and the component (B) cannot be obtained in a sufficient ratio. Above the range described in paragraph 0093, the activity becomes too high, so that the removal of the polymerization heat cannot catch up, and the polymer powder may melt and generate lumps.

  Here, the particle size of the polymer powder to be produced is preferably 700 μm or more, more preferably 850 μm or more, still more preferably 1,000 μm or more, on the other hand, preferably 4,000 μm or less, more preferably 3,500 μm or less, More preferably, it is 3,000 micrometers or less. If it is within this range, “holding property of the polymer powder of the component (B) is lowered, bleed is likely to occur, and when the particle size is excessive, problems such as crushing in the stirring and the transfer of the polymer powder. Can be effectively prevented.

The operational stability can be judged from the flow state of the polymer powder sampled after the second step. As an indicator of the flow state, BD (bulk density) of the polymer powder is appropriate.
The polymer powder BD capable of maintaining stable drivability is 0.40 g / ml or more, more preferably 0.44 g / ml or more, and 0.55 g / ml or less, preferably 0.49 g / ml or less. It is.
Within this range, there will be no “stirring failure due to fluidity drop and piping clogging during transportation, which makes it difficult to continue operation”, and stirring power does not increase significantly.

[VI] Post-treatment step of polymer powder (1) Basic treatment The polymer particles of the soft polymer of the present invention can be obtained by subjecting the polymer powder obtained in the polymerization step to, for example, the following post-treatment step. . By receiving each treatment of the drying step and the aeration step as a post-treatment step, (a) the polymer is easily sticky and the problem that the polymer particles adhere to each other is suppressed, and (b) from the polymer particles, Residual volatile components such as residual monomers and residual solvents can be efficiently and sufficiently removed, and (c) blocking of silos and the like due to pressure bonding of the polymer particles can be suppressed.

The post-processing step preferably has the following two steps.
Step a): A step of drying the polymer powder at a temperature of 60 to 95 ° C. and drying for 0.6 to 1.1 hours.
Step b): A step of aeration of the polymer powder at a temperature of 25 to 95 ° C. for 6 to 50 hours.
Moreover, it is preferable to perform a post-processing process in order of process a) and process b).
Hereinafter, the drying method and aeration of the polymer powder of the present invention will be described specifically and in detail.

The polymer powder of the present invention basically does not need to be particularly distinguished from those obtained by polyolefin polymerization and those obtained by other methods.
The technique of the present invention is mainly intended to produce a soft propylene-based block copolymer and the like, and is preferably applied to a polymer powder obtained by gas phase polymerization for the reason of maintaining powder fluidity.
Drying here refers to propylene, ethylene, C4 to C20 α-olefin fed at the time of polymer production, hexane, heptane and other hydrocarbons used in the catalyst slurry, and unreacted monomers and residual solvent during polymerization. Is to remove. This includes a case corresponding to so-called deaeration. Moreover, in order to deactivate a catalyst and organic aluminum in the inert gas used for drying, it is common to make water vapor | steam contain and ventilate. Furthermore, drying is preferably performed while the polymer powder is fluidized.

  On the other hand, aeration refers to injecting air, nitrogen gas, etc. into the granular material layer as described in the glossary of powder engineering (2nd edition, p.21, edited by the Powder Engineering Society, published by Nikkan Kogyo Shimbun). An operation. An object of the present invention is to supply an inert gas such as nitrogen to the bottom of the container and bring the gas contained in the polymer powder filled in the container and the gas in the container into an equilibrium state. It refers to a process of reducing residual hydrocarbons (including residual monomers) to about 1,400 wtppm or less by ventilating nitrogen or the like to the polymer powder after the drying process at a flow rate that does not flow. In the drying process, aeration is a process for managing the residual gas concentration when storing polymer powder such as silos, while removing unreacted monomer and residual solvent mainly using a dryer. It is distinguished from the drying process.

(2) Step a)
The form of the drying device is not particularly limited in shape and structure, but the dryer used in the present invention is, for example, a powder engineering manual (2nd edition, p.358, edited by the Powder Engineering Society, published by Nikkan Kogyo Shimbun). However, it may be a batch type or a continuous type, and any type such as a stirring type, a vibration type, and a screw conveyor type may be used. It is also possible to combine various types of drying apparatuses.

  The temperature condition in step a) is 60 ° C. or higher, preferably 65 ° C. or higher, more preferably 70 ° C. or higher and 95 ° C. or lower, preferably 90 ° C. or lower, more preferably 85 ° C. or lower. When the temperature is 60 ° C. or higher, the polymer powder can be sufficiently dried. When the temperature is 95 ° C. or lower, the polymer powders are not fixed to each other regardless of the temperature in step b). Silo blockage does not occur. The temperature here is the temperature of the polymer powder in the dryer.

  The drying time conditions in step a) are 0.6 hours or more, preferably 0.7 hours or more and 1.1 hours or less, preferably 1.0 hours or less. If the time is 0.6 hours or longer, the polymer powder can be sufficiently dried. If the time is 1.1 hours or shorter, the drying process equipment does not increase in size, and the intermediate during the switching of the production grade. It is possible to avoid an increase in product and an increase in manufacturing cost.

Residual gas concentrations such as residual hydrocarbons are lower than before step a), and as a result of step a), the preferred gas concentration after step a) is in the range of 250 wtppm to 1,400 wtppm. Yes, more preferably 275 wtppm or more and 1,150 wtppm or less, particularly preferably 300 wtppm or more and 900 wtppm or less.
When the soft polymer is a propylene-based block copolymer and the propylene-α-olefin copolymer component is a propylene-ethylene random copolymer, the residual gas concentration of the residual hydrocarbon is compared with that before step a). As a result of performing step a), the preferable gas concentration after step a) is in the range of 250 wtppm or more and 1,400 wtppm or less, more preferably 275 wtppm or more and 1,150 wtppm or less, Preferably they are 300 wtppm or more and 900 wtppm or less.
When the soft polymer is a propylene-based block copolymer and the propylene-α-olefin copolymer component is a propylene-ethylene-butene random copolymer, the preferred residual gas is that the boiling point of butene is higher than that of ethylene. The concentration ranges from 375 wtppm to 2,100 wtppm, more preferably from 410 wtppm to 1,725 wtppm, and particularly preferably from 450 wtppm to 1,200 wtppm.

(3) Step b)
The location of the aeration and the shape of the aeration apparatus are not particularly limited, but it is efficient when performed in a silo after the drying process. After the drying step, the polymer powder can be sufficiently dried and the residual gas can be controlled with a small amount of aeration gas without increasing the temperature of the polymer powder. In addition, aeration can be performed outside of the silo, but it is necessary to feed the aeration gas from the lower part of the silo, allowing the polymer powder and gas to contact in countercurrent and efficiently replace the entire silo gas. The amount of aeration gas is also low and it is economical. Therefore, a silo is preferable as a form in which a large amount of polymer powder is dried by aeration.
In the drying process, aeration is a process for managing the residual gas concentration when storing polymer powder such as silos, while removing unreacted monomer and residual solvent mainly using a dryer. It is distinguished from the drying process. In this case, it is necessary to take measures so that the polymer powders are not pressure-bonded.

The gas used for aeration is preferably an inert gas. Nitrogen is particularly preferable from the viewpoint of economy and availability. The gas for aeration is preferably fed from the lower part of the silo. When feeding from the upper part of the silo, the polymer powder in the silo cannot be sufficiently contacted, so that there is a possibility that some polymer powders cannot be managed sufficiently.
The amount of aeration gas is preferably 0.1 Nm ³ / h or more per unit retained amount (polymer powder 1T). If it is above this value, gas replacement is sufficiently performed in the silo, and the polymer powder can be adequately managed. Although there is no upper limit, it is desirable not to increase the feed amount extremely from the viewpoint of production cost.

  The temperature condition of step b) is preferably 25 to 95 ° C. When the temperature is 25 ° C. or higher, residual volatile components can be sufficiently removed, and it is possible to prevent the polymer powders after passing through the drying process from being fixed to each other and the polymer powders from being extracted from the silo. On the other hand, if the setting is 95 ° C. or lower, it is possible to avoid the need for heating equipment for the entire silo and a significant increase in manufacturing cost.

The drying time condition in step b) is 6 hours or more, preferably 9 hours or more, more preferably 12 hours or more and 50 hours or less, preferably 45 hours or less, more preferably 40 hours or less. When it is 6 hours or more, the polymer powder can be sufficiently processed. When it is 50 hours or less, the silo scale is appropriate, and the production cost per unit time is appropriate.
It is desirable to measure the temperature of the polymer powder at the bottom of the silo because blockage tends to occur at the bottom of the silo. On the other hand, in the examples of the present invention, the temperature of the actually sampled polymer powder was directly measured.

The residual gas concentration of the residual hydrocarbon is further reduced as compared to before the step b), and as a result of performing the step b), the preferable gas concentration after the step b) is the lower limit of explosion of the monomer gas contained, particularly propylene. It is as follows.
However, in the second step, when butene is used to produce a propylene-ethylene-butene random copolymer, since the boiling point of butene is higher than that of ethylene or propylene, the lower explosion limit value becomes larger as an absolute value. .

(4) Consideration of processing temperature In addition, based on the past results and experience, the present inventors focused on the behavior of polymer powders with respect to heat, and advanced research.
A polymer which is a thermoplastic resin as in the present invention has a melting point. When the polymer exceeds its inherent melting point, the degree of freedom of the molecules in the crystalline component of the polymer increases and begins to exhibit properties as a viscous body. In the case of soft olefin polymer particles comprising a crystalline component and a non- (low) crystalline component as in the present invention, the non- (low) crystalline property increases as the temperature increases and the molecular motion of the crystalline component increases. A phenomenon called so-called bleed out occurs in which components move onto the polymer surface. This phenomenon begins to occur significantly from a temperature (T) slightly below the melting point, even though the polymer temperature does not necessarily exceed the melting point of the crystalline component. Moreover, the degree becomes larger as time passes.

  Therefore, in the present invention, a drying step for separating the polymer particles from the unreacted monomer and solvent is necessary, and it is preferable that the temperature is higher considering only the separation, but drying is performed while suppressing bleed out. Therefore, in step a) which is a drying step, it is necessary to dry at a temperature lower than the temperature (T) slightly lower than the melting point of the polymer.

However, as described above, the bleed-out phenomenon is a phenomenon that occurs little by little as time passes even if drying is performed at T ° C. or less, and cannot be completely suppressed. The state of the polymer causing the bleed-out is that the surface of the polymer particle is covered with an amorphous component. However, even for non- (low) crystalline components that cause bleed out, non- (low) crystalline properties when the temperature of the polymer drops to near the glass transition temperature of this non- (low) crystalline component. The molecular motion of the component becomes smaller. At this time, when the molecular motion is reduced while the non- (low) crystalline components of the polymer particles whose surfaces are covered with the non- (low) crystalline component are in contact with each other, the non-(( Low) A so-called binder phenomenon occurs in which crystalline components are fixed to each other.
At this time, if a binder phenomenon occurs in a place where a polymer such as a silo is stacked and stored, the fluidity of the entire polymer particle is impaired, and the polymer cannot be extracted from the silo. It causes the problem of being unable to do it.

  Therefore, in the present invention, the step of removing the volatile components in the polymer particles after the polymer in which the bleedout has progressed in a specific range through a specific temperature history in the drying step of removing unreacted monomers and solvent components. In the aeration operation of b), by not reducing the temperature during aeration below the temperature (T) near the glass transition temperature of the polymer, the fluidity of the polymer particles is not significantly impaired, and the unreacted monomer or solvent component Drying of removal and removal of volatile components in the polymer particles can be sufficiently performed. As a result, it was found that the polymer particles of the present invention can be easily produced.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the examples, and each example is not limited to the rationality and significance of the configuration of the present invention in comparison with the comparative examples. It demonstrates the superiority and usefulness of the conventional technology.

[Manufacture of catalyst]
Silicate chemical treatment: To a glass separable flask with a 10 liter stirring blade, 3.75 liters of distilled water was added slowly followed by 2.5 kg of concentrated sulfuric acid (96%). 5
At 0 ° C., 1 kg of montmorillonite (Menzawa Chemical Co., Ltd. Benclay SL; average particle diameter = 50 μm) was further dispersed, heated to 90 ° C., and maintained at that temperature for 6.5 hours. After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake to reslurry, and then filtered. This washing operation was performed until the pH of the washing solution (filtrate) exceeded 3.5. The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The mass after drying was 707 g. The chemically treated silicate was further dried in a kiln dryer.

  Preparation of catalyst: 200 g of the dried silicate obtained above was introduced into a glass reactor equipped with a stirring blade having an internal volume of 3 liters, and 1,160 ml of mixed heptane and further 840 ml of a heptane solution of triethylaluminum (0.60 M) were added. Added and stirred at room temperature. After 1 hour, the mixture was washed with mixed heptane to prepare a silicate slurry at 2.0 liters. Next, 9.6 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added to the prepared silicate slurry and reacted at 25 ° C. for 1 hour. In parallel, [(r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azurenyl}] zirconium] (synthesized in JP-A-10-226712) 33.1 ml of a heptane solution of triisobutylaluminum (0.71 M) was added to 2,180 mg (3 mmol) and 870 ml of mixed heptane (performed according to the example), and the mixture reacted at room temperature for 1 hour was added to a silicate slurry. Added and stirred for 1 hour.

Preliminary polymerization: Subsequently, 2.1 liters of n-heptane was introduced into a stirring autoclave having an internal volume of 10 liters that had been sufficiently substituted with nitrogen, and maintained at 40 ° C. The previously prepared silicate / metallocene complex slurry was introduced therein. When the temperature was stabilized at 40 ° C., propylene was supplied at a rate of 100 g / hour to maintain the temperature. After 4 hours, the supply of propylene was stopped and maintained for another 2 hours. After completion of the prepolymerization, the remaining monomer was purged, stirring was stopped and the mixture was allowed to stand for about 10 minutes, and then about 3 liters of the supernatant was decanted. Subsequently, 9.5 ml of a heptane solution of triisobutylaluminum (0.71 M / L) and 5.6 liters of mixed heptane were added, and the mixture was stirred at 40 ° C. for 30 minutes and allowed to stand for 10 minutes. Removed 6 liters. This operation was further repeated 3 times. When the component analysis of the final supernatant was performed, the concentration of the organoaluminum component was 1.23 mmol / L and the Zr concentration was 8.6 × 10 ⁻⁶ g / L, and the abundance in the supernatant with respect to the amount charged. Was 0.016%. Subsequently, 17.0 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added, followed by drying at 45 ° C. under reduced pressure. By this operation, a prepolymerized catalyst containing 2.1 g of polypropylene per 1 g of catalyst was obtained.

[Example 1]
(1) First polymerization step
After introducing 35 kg of seed polymer in advance into a first horizontal polymerization vessel (L / D = 5.6, internal volume 100 L) having stirring blades, nitrogen gas was circulated for 3 hours. Thereafter, the temperature was raised while introducing propylene, ethylene and hydrogen, and when the polymerization conditions were satisfied, the above prepolymerized catalyst was 0.47 g / hr, and triisobutylaluminum as an organoaluminum compound was constant at 15 mmol / hr. Was fed as A mixed gas of ethylene / propylene in a ratio of 1: 3 is continuously supplied while maintaining conditions of a reaction temperature of 75 ° C., a reaction pressure of 1.8 MPaG, and a stirring speed of 35 rpm, and hydrogen gas is continuously supplied to produce a polymer produced. Adjusted.

  The heat of reaction was removed by the heat of vaporization of the raw material propylene. The unreacted gas discharged from the polymerization reactor was cooled and condensed outside the reactor system and refluxed to the polymerization reactor. The propylene-ethylene random copolymer component (A) obtained by the main polymerization was intermittently extracted and supplied to the polymerization vessel in the second polymerization step.

(2) Second polymerization step
Propylene-ethylene random copolymer component (A) from the first polymerization step and a mixed gas of propylene and ethylene are fed to a second horizontal polymerization vessel (L / D = 5.6, internal volume 100 L) having stirring blades. Each was supplied to carry out copolymerization of propylene and ethylene. The reaction conditions were a stirring speed of 18 rpm, a reaction temperature of 70 ° C., a reaction pressure of 1.7 MPaG, and the gas composition in the gas phase was adjusted. No hydrogen feed was performed in the second polymerization step. The heat of reaction was removed by the heat of vaporization of the raw material propylene. The unreacted gas discharged from the polymerization reactor was cooled and condensed outside the reactor system and refluxed to the polymerization reactor.
The propylene-based block copolymer produced in the second polymerization step was continuously extracted from the polymerization vessel.

(3) Post-processing step In a vertical dryer having an internal volume of 400 L shown in FIG. 1, propylene-based block copolymer polymer powder obtained through the first polymerization step and the second polymerization step, and nitrogen are added. The solution was continuously introduced at 8 m ³ / hour and dried at 0.05 MPaG and 80 ° C. for 0.8 hours (step a)). A part of the polymer powder after step a) was sampled, and the amount of volatile matter was measured and found to be 720 wtppm.
Thereafter, the polymer powder from step a) is transferred to a silo having an internal volume of 0.6 m ³ , the polymer is stacked, and aeration is performed by flowing nitrogen at 8 m ³ / hour at 0.05 MPaG and a temperature of 30 ° C. for 34 hours. (Step b)). After step b), polymer particles were taken out from the top of the silo and analyzed, and the amount of volatile matter was 42 wtppm. The values relating to the fluidity and quality of other polymer particles are also shown in Table 1.

(4) Evaluation method of polymer blockage When 100 g of the obtained polymer particles were passed through a funnel having an inner diameter of 12φ, they passed through the funnel only by their own weight.

[Example 2]
Although it carried out similarly to Example 1, the molecular weight of the ethylene / propylene polymer produced | generated at a 2nd polymerization process was adjusted low by feeding hydrogen at a 2nd polymerization process. Then, the post-processing process similar to Example 1 was performed. When 100 g of the obtained polymer particles were passed through a funnel having an inner diameter of 12φ, they passed through the funnel only by their own weight.

[Comparative Example 1]
In Example 1, the conditions of the post-treatment process were changed as follows. A propylene block copolymer polymer powder obtained through the first polymerization step and the second polymerization step and nitrogen are continuously introduced into a vertical dryer having an internal volume of 400 L at a rate of 8 m ³ / hour. Dry at 0.05 MPaG and 80 ° C. for 3 hours (step a)). A part of the polymer powder after step a) was sampled, and the amount of volatile matter was measured and found to be 100 wtppm.
Thereafter, the polymer powder from step a) was transferred to a silo having an internal volume of 0.6 m ³ and the polymer was stacked and allowed to stand at 0.05 MPaG and a temperature of 30 ° C. for 34 hours without aeration (step b)). . After step b), polymer particles were taken out from the top of the silo and analyzed. The amount of volatile matter was 100 wtppm. When 100 g of the obtained polymer particles were passed through a funnel having an inner diameter of 12φ, the funnel was blocked.

[Example 3]
In the same manner as in Example 1, but instead of supplying a mixed gas of propylene and ethylene in the second polymerization step, a mixed gas of propylene, ethylene and butene was supplied at a ratio of 4: 4: 1, and propylene, A propylene-ethylene-butene ternary propylene-based block copolymer was produced by copolymerization of ethylene and butene. Then, the post-processing process similar to Example 1 was performed.
The polymer powder obtained had an elution amount of 25 wt% or less at 40 ° C. or less in TREF measurement, an ethylene content of 16 wt% or less, and a butene content of 30 wt% or less in a TREF 40 ° C. or less soluble content. The propylene concentration as residual volatile matter was 15 wtppm, the butene concentration was 78 wtppm, a total of 93 ppm, which was below the lower limit of explosion. When 100 g of the obtained polymer particles were passed through a funnel having an inner diameter of 12φ, they passed through the funnel only by their own weight.

[Consideration of Comparison Results of Examples and Comparative Examples]
As is clear from Examples 1 to 3 and Comparative Example 1, the polymer particles of the examples according to the propylene-ethylene block copolymer and propylene-ethylene-butene copolymer satisfying the definition of the present invention are fluid. It was found that the residual volatile matter was efficiently and sufficiently removed, and no blockage occurred.
The polymer particles of Comparative Example 1 were particles having a large residual volatile content and a large angle of repose because the drying time was long and the aeration was not performed in the post-treatment step of the polymer powder. The result was inappropriate.
Thus, the rationality, significance and usefulness of the construction of the present invention and the superiority over the prior art are demonstrated.

The polymer particles of the soft polymer of the present invention increase the melt fluidity (MFR) of the polymer in order to shorten the molding cycle and further improve the moldability. This makes it easier to prevent the polymer particles from adhering to each other, efficiently and sufficiently removes residual volatiles such as residual monomers and residual solvents from the polymer particles, Etc. can also be suppressed.
Therefore, the present invention is very useful industrially in the field of production and use of olefinic thermoplastic elastomers.

1. First horizontal polymerization vessel 1. 2. Second horizontal polymerization vessel 3. Vertical stirring dryer 4. Transportation piping to the silo Silo 6. 6. Nitrogen piping for aeration Transport piping to granulator (not shown)

Claims (13)

Soft polymer polymer particles that meet the following requirements.
a) In TREF (temperature rising elution fractionation), the component eluting at 40 ° C. or less is 23 wt% or more b) The volatile content of the polymer particles is 100 wtppm or less c) The angle of repose of the polymer particles is 20 to 55 ° Is Soft polymer polymer particles that meet the following requirements.
a) In TREF (temperature rising elution fractionation), the component eluting at 40 ° C. or lower is 30 wt% or more b) The volatile content of the polymer particles is 50 wtppm or less c) The angle of repose of the polymer particles is 20 to 55 ° Is 3. A polymer particle of a soft polymer, wherein a bending elastic modulus of a molded article using the polymer particle of claim 1 or 2 is 50 to 400 MPa. The melting point of the polymer particles is 115 to 145 ° C, the bulk density is 0.40 to 0.49 g / ml, and the effective internal friction angle is 20 to 55 °. The polymer particle of the soft polymer as described in any one of the above. The soft polymer is a propylene-based random copolymer or a propylene-based block copolymer containing a propylene unit and an ethylene unit or a C4 to C20 α-olefin unit. 2. Polymer particles of the soft polymer according to item 1. The soft polymer is a propylene-based random copolymer or a propylene-based block copolymer containing a propylene unit, an ethylene unit, and a C4 to C20 α-olefin unit. 2. Polymer particles of the soft polymer according to item 1. The soft polymer polymer particle according to any one of claims 1 to 6, wherein the soft polymer is a propylene-based block polymer polymerized with a metallocene catalyst. In TREF, the component eluting at 40 ° C. or less is a copolymer of propylene units and ethylene units or C4 to C20 α-olefin units, and the weight average molecular weight (Mw) is 150,000 to 250,000. The polymer particle of the soft polymer according to any one of claims 1 to 5 and 7, wherein the polymer particle is a polymer particle. In TREF, the component eluting at 40 ° C. or less is a copolymer of propylene units, ethylene units and C4-C20 α-olefin units, and the weight average molecular weight (Mw) is 150,000 to 250,000. The polymer particle of a soft polymer according to any one of claims 1 to 4, 6, and 7, wherein the polymer particle is a polymer particle. A method for producing polymer particles of a soft polymer according to any one of claims 1 to 5, 7, and 8, comprising propylene units and ethylene units or C4 to C20 α-olefin units. A method for producing polymer particles of a soft polymer, wherein when polymerizing a random copolymer or a propylene block copolymer, part or all of the polymerization step is gas phase polymerization. It is a method of manufacturing the polymer particle of the soft polymer of any one of Claims 1-4, 6, 7, and 9, Comprising: A propylene unit, an ethylene unit, and the alpha olefin unit of C4-C20 are included. A method for producing polymer particles of a soft polymer, wherein when polymerizing a propylene random copolymer or a propylene block copolymer, part or all of the polymerization step is gas phase polymerization. A method for producing the polymer particles of the soft polymer according to any one of claims 1 to 9, comprising a polymerization step and a post-treatment step after the polymerization step, and the post-treatment step includes the following two steps: A process for producing polymer particles of a soft polymer, characterized by comprising:
Step a): A step of drying the polymer powder at a temperature of 60 to 95 ° C. for 0.6 to 1.1 hours.
Step b): A step of aeration of the polymer powder at a temperature of 25 to 95 ° C. for 6 to 50 hours. The method for producing polymer particles of a soft polymer according to claim 12, wherein the aeration is performed by a silo.

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