JP2017096666A - Method for measuring inner structure of polyolefin particles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method that can precisely and easily measure inner structure information, including the three-dimensional distributions in an amorphous part, a crystal part, and an empty part in the inside of polyolefin particles and the ratios of existence in the parts, while suppressing damages on the polyolefin particles at the measurement, even if the difference in density between the crystal part and the amorphous part is small and the measurement target is polyolefin particles with smaller X-ray absorption.SOLUTION: There is provided the method for measuring the inner structure of polyolefin particles, that uses an X-ray micro computer tomography for measuring polyolefin particles in which a dyeing agent made of a heavy metal compound is selectively introduced in an amorphous part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for measuring the internal structure of polyolefin particles, and more specifically, a method for measuring internal structure information such as the three-dimensional distribution of amorphous parts, crystal parts and voids in polyolefin particles, and the existence ratio of each part. About.

  In recent years, many olefin polymerization catalysts have been proposed that contain magnesium, transition metals and electron donors as essential components. For example, magnesium compounds such as magnesium chloride and diethoxymagnesium are all dissolved in alkoxy titanium compounds. Thus, a transition metal-containing solid catalyst formed by forming a uniform solution and then precipitating is proposed (for example, Patent Document 1 (Japanese Patent Laid-Open No. 62-18405) or Patent Document 2 (Japanese Patent Laid-Open No. 3-72503). Publication))).

  By the way, there are various polyolefins obtained by polymerizing olefins, such as polyethylene, polypropylene, and copolymers of α-olefin and propylene. In these polyolefin polymer particles, amorphous parts are present. A three-dimensional structure composed of a crystal part and a void part is formed.

  The internal structure such as the three-dimensional distribution state of amorphous parts, crystal parts and voids in the above polyolefin particles, and the proportion of each part, etc., is related to the manufacturing process of polyolefin, the process of processing into the final product, and the mechanical properties of the final product. In order to exert a great influence, a method for measuring the internal structure simply and accurately has been demanded.

  To confirm the internal structure of the polyolefin particles, the sample is processed into an ultrathin section using a microtome or ultramicrotome at room temperature or under freezing, with the polyolefin particles embedded directly or in an epoxy resin. There are methods such as observation with a transmission electron microscope (TEM) and a scanning electron microscope (SEM).

JP-A-62-18405 JP-A-3-72503

However, in the method of processing the sample into an ultra-thin section, stress is applied when cutting the sample, so stress damage during cutting remains on relatively soft polyolefin particles, and an accurate internal state is read from the cut surface. Is difficult.
In addition, when an ultrathin slice is produced in an embedded state in an epoxy resin or the like, although the stress damage during cutting is reduced, the boundary between the resin used for embedding and the polyolefin particles becomes unclear.

  On the other hand, due to remarkable advances in analytical instruments in recent years, a method for easily observing the inside of an object has been developed. As such a method, for example, a focused ion beam method (a so-called FIB method), that is, an apparatus vacuum chamber is used. The held sample is irradiated with a positive high-voltage gallium ion beam focused to a diameter of several nanometers to several hundred nanometers, and a scanning ion image (so-called SIM image) using secondary ions generated from the sample surface as a signal is observed. The method of doing is mentioned.

According to the FIB method, it is possible to irradiate an ion beam to an arbitrary region while observing a SIM image or an SEM image. However, as a result of investigation by the present inventors, a cross-sectional image is obtained when polyolefin particles are observed by the FIB method. When it was tried to observe in detail, it was found that the heat energy at the time of ion beam irradiation could not be removed and the observation part (beam irradiation part) was melted. For this reason, it is difficult to accurately grasp the internal structure of the polyolefin particles by the FIB method.
Also, the FIB method requires a long time to cut and analyze polyolefin particles having a small area that can be processed at a time and having a size of several millimeters or more, and is not easily measured.

On the other hand, a method using an ion slicer using an argon ion beam or a cross-section polisher is also known as a specimen cutting device, and the area that can be processed at a time is wider than the FIB method using a gallium ion beam, and the internal cross-sectional structure It is an effective analysis method for grasping widely.
When the test piece is cut using the apparatus as described above, a shielding plate excellent in heat conduction such as a silicone wafer is generally used in order to reduce thermal damage during irradiation with the argon ion beam.
However, according to the study by the present inventors, it has been found that when polyolefin particles are used as an observation sample, the cut surface (ion beam irradiation surface) is melted even if the shielding plate is used.
For this reason, even if it uses the cutting method using an argon ion beam, it is still difficult to grasp | ascertain the internal structure of polyolefin particle | grains.

As described above, the conventional method requires a long time for measurement and is a method of cutting and destroying the sample, and thus is not a simple method. In addition, heat damage to polyolefin particles is large, and it is difficult to obtain accurate information inside the particles with good reproducibility. The information obtained is only two-dimensional projection, and only partial internal structure information can be obtained. As a result, the internal structure of the entire polyolefin particle could not be accurately grasped.
For this reason, there has been a demand for a method for observing the three-dimensional structure of the entire polyolefin particle simply and accurately without cutting or destroying the sample.

  Under such circumstances, the present invention eliminates thermal damage to the polyolefin particles during observation, and the three-dimensional distribution of amorphous parts, crystal parts and voids inside the polyolefin particles, and the internal ratio of each part, etc. The object is to provide a method for simply and accurately evaluating structural information.

  In order to solve the above technical problem, the present inventors have conceived a method of observing polyolefin particles using X-ray Micro Computed Tomography.

  The principle of the X-ray micro computer tomography apparatus is the same as that of a CT scan used as a medical device in a hospital. In the measurement method using the X-ray micro computer tomography, when a sample is irradiated with X-rays, It was considered that the change in the amount of X-ray absorption can be converted and visualized as the change in image contrast, and that such a technique can be applied to the measurement of the internal structure of polyolefin.

  However, as a result of studies by the present inventors, X-ray absorption generally increases in proportion to the density and thickness of the sample. Therefore, in a sample having a high density, such as a metal, and X-ray absorption, However, it has been found that X-ray absorption is weak in a sample having a low density and a small thickness such as polyolefin particles.

Furthermore, when the present inventors examined, as for the density of crystalline polyolefin, polyethylene (PE) 0.90g / cc-0.96g / cc, polypropylene (PP) 0.85g / cc-0.95g / cc. The density of amorphous polyolefin such as olefin copolymer is 0.86 g / cc to 0.87 g / cc, whereas the density range is close to each other. .
In general, the density difference required for visualization using an apparatus using X-rays as a light source (visually distinguishing between crystalline polyolefin and amorphous polyolefin) is 0.05 g / cc to 0.10 g / cc. However, since it is more than that, it is very difficult to distinguish the components having close densities as described above.

  Under these circumstances, the present inventors conducted further diligent investigations, and as a result of selectively staining the amorphous part of the polyolefin particles, the above technical problem was solved by measuring using X-ray micro computer tomography. The present invention has been found out, and the present invention has been completed based on this finding.

That is, the present invention
(1) A method for measuring the internal structure of a polyolefin particle, wherein polyolefin particles into which a staining agent comprising a heavy metal compound is selectively introduced into an amorphous part are measured using X-ray microcomputer tomography,
(2) The method for measuring the internal structure of the polyolefin particles according to (1), wherein the heavy metal compound is ruthenium tetrachloride,
(3) The polyolefin particles described above in (1) or (2), wherein the polyolefin particles contain polypropylene, or contain a propylene-α-olefin copolymer containing ethylene or an α-olefin having 4 to 8 carbon atoms. Method for measuring the internal structure of polyolefin particles,
(4) The method for measuring the internal structure of a polyolefin particle according to any one of (1) to (3), wherein the polyolefin particle contains 0.05 to 70% by mass of an ethylene-propylene copolymer,
Is to provide.
Hereinafter, the X-ray micro computer tomography is appropriately referred to as XMCT.

  According to the present invention, after selectively introducing a staining agent comprising a heavy metal compound into an amorphous part in a polyolefin particle, and measuring by XMCT, the polyolefin particle having weak X-ray absorption has an internal density difference. Even when the crystal part and the amorphous part are small, the amorphous part inside the polyolefin particle without cutting or destroying the sample and suppressing damage to the polyolefin particle at the time of observation. In addition, it is possible to simply and accurately evaluate the internal structure information such as the three-dimensional distribution including the crystal part and the void part and the existence ratio of each part.

It is the schematic which shows an example of a XMCT apparatus. 3 is a three-dimensional image of XMCT analysis obtained in Example 1. FIG. 6 is a histogram image of XMCT analysis obtained in Example 1. FIG. 3 is a three-dimensional image of XMCT analysis obtained in Comparative Example 1. 6 is a histogram image of XMCT analysis obtained in Comparative Example 1. 3 is a three-dimensional image of XMCT analysis obtained in Example 2. FIG. It is a three-dimensional image of XMCT analysis obtained in Example 3

  The method for measuring the internal structure of polyolefin particles according to the present invention is characterized in that polyolefin particles in which a dyeing agent comprising a heavy metal compound is selectively introduced into an amorphous part are measured using X-ray micro computer tomography. is there.

  In the present invention, the polyolefin particles to be measured are not particularly limited. Examples of the polymer constituting the polyolefin particles include ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, and vinylcyclohexane. Examples thereof include polymers of one or more olefins selected from the group consisting of ethylene and propylene, and propylene is particularly preferable.

The polymer constituting the polyolefin particles of the present invention may be a copolymer, and the copolymer is preferably a propylene-α-olefin copolymer, and a propylene-α-olefin block copolymer. It is preferable that
In the present application documents, the block copolymer is a polymer including a segment in which two or more types of monomer compositions continuously change, and includes monomer type, comonomer type, comonomer composition, comonomer content, comonomer sequence, This means that two or more types of polymer chains (segments) having different primary structures such as stereoregularity are connected in one molecular chain.

  In the propylene-α-olefin copolymer, the olefin copolymerized with propylene is preferably ethylene or an α-olefin having 4 to 8 carbon atoms, specifically, ethylene, 1-butene, 1 -One or more types selected from -pentene, 4-methyl-1-pentene, vinylcyclohexane and the like can be mentioned. As the olefins copolymerized with propylene, ethylene or 1-butene is particularly preferable.

  When the polymer constituting the polyolefin particles is a propylene-α-olefin copolymer, the copolymer is 0.1 to 50 mol of ethylene or an α-olefin having 4 to 8 carbon atoms in the copolymer. %, More preferably 0.1 to 40 mol%, and even more preferably 0.1 to 30 mol%.

  As the polymer constituting the polyolefin particles, polypropylene or a propylene-α-olefin copolymer containing 0.1 to 30 mol% of ethylene or an α-olefin having 4 to 8 carbon atoms is preferable.

The polyolefin particles preferably contain 0.05 to 70% by mass of propylene-α-olefin copolymer, more preferably 0.1 to 60% by mass, and more preferably 0.1 to 50% by mass. Further preferred.
As the propylene-α-olefin copolymer, an ethylene-propylene copolymer is suitable.

  The polyolefin particles preferably have an average particle size of 100 to 5,000 μm, preferably have an average particle size of 200 to 4,000 μm, and more preferably have an average particle size of 300 to 3,000 μm.

  In addition, in this application document, the average particle diameter of polyolefin particle | grains is the integration | accumulation of a volume reference | standard integrated particle size distribution obtained when it measures using an image-analysis type | formula particle size distribution measuring apparatus (the Retsch TECHNOLOGY company make, model: CAMSIZER). It shall mean 50% particle size (D50).

In the present invention, the polyolefin particles to be measured may be those obtained by polymerizing olefins in the presence or absence of an organic solvent, and those obtained by polymerizing either gaseous or liquid olefins. May be.

  In the present invention, the polyolefin particles to be measured can be obtained, for example, by introducing olefins in the presence of an olefin polymerization catalyst in a reactor such as an autoclave and polymerizing under heating and pressure. it can.

  The olefin polymerization catalyst used for the preparation of the polyolefin particles is not particularly limited. For example, (A) a support such as a metal oxide or a metal halogen compound, a transition metal compound such as titanium, and further if necessary. Solid catalyst component supporting an internal electron donating compound, (B) a solid catalyst containing an organoaluminum compound and, if necessary, (C) an external electron donating compound, a homogeneous transition metal catalyst such as a metallocene catalyst, etc. Can be mentioned.

The polymerization temperature for polymerizing the olefins is usually 200 ° C. or lower, preferably 100 ° C. or lower, more preferably 60 to 100 ° C., and 70 to 90 ° C. from the viewpoint of improving activity and stereoregularity. Is more preferable. The polymerization pressure when polymerizing the olefins is preferably 10 MPa or less, and more preferably 5 MPa or less.
Moreover, any of a continuous polymerization method and a batch type polymerization method is possible. Furthermore, the polymerization reaction may be performed in one stage or in two or more stages.

  When the polymer constituting the polyolefin particles is a propylene-α-olefin copolymer, the block copolymerization reaction of propylene and other α-olefins for producing the propylene-α-olefin copolymer is: Usually, in the presence of the catalyst for olefin polymerization of the present invention, propylene alone or propylene and a small amount of α-olefin (ethylene, etc.) are contacted in the former stage, and then propylene and α-olefin (ethylene, etc.) are brought into contact with the latter stage. It can implement by making it contact. The preceding polymerization reaction may be repeated a plurality of times, or the latter polymerization reaction may be repeated a plurality of times by a multistage reaction.

Specifically, in the block copolymerization reaction of propylene with other olefins, the polymerization temperature and time are adjusted so that the proportion of the polypropylene portion (occupying the copolymer finally obtained) becomes the desired proportion in the previous stage. Then, in the subsequent stage, propylene and ethylene or other α-olefin are introduced, and the ratio of the rubber part such as ethylene-propylene rubber (EPR) (occupying in the finally obtained copolymer) is a desired ratio. Polymerize to become.
The polymerization temperature in the former stage and the latter stage is preferably 200 ° C. or lower, more preferably 100 ° C. or lower, and the polymerization pressure is preferably 10 MPa or lower, more preferably 5 MPa or lower.

  In the above copolymerization reaction, either a continuous polymerization method or a batch polymerization method can be employed. The polymerization reaction may be performed in one stage or in two or more stages.

  Further, the polymerization time (residence time in the reaction furnace) is preferably 1 minute to 5 hours in the respective polymerization stages of the preceding stage or the subsequent stage, or also in the continuous polymerization.

  As polymerization methods for olefins, slurry polymerization methods using a solvent of an inert hydrocarbon compound such as cyclohexane and heptane, bulk polymerization methods using a solvent such as liquefied propylene, and a gas phase polymerization method using substantially no solvent. A bulk polymerization method or a gas phase polymerization method is preferred, and the subsequent reaction is generally a gas phase polymerization reaction for the purpose of suppressing elution of EPR from PP particles. The process may be combined in multiple stages. For example, an ethylene-propylene block copolymer can be obtained by performing propylene polymerization in the former stage and carrying out ethylene-propylene copolymer in the latter stage.

The polyolefin particles to be measured in the present invention may be in the form of a thin film cut by a microtome or an ion slicer. The polyolefin particles to be measured may contain a small amount of additive components, and examples of these additive components include antioxidants and talc.
At this time, the content of the additive component in the polyolefin particles is preferably 0.1 to 50% by mass, more preferably 0.1 to 40% by mass, and further preferably 0.1 to 30% by mass.

  When the polyolefin particles contain the above-mentioned additive component, for example, they can be prepared by adding additives such as an antioxidant and talc to one or more kinds of polyolefin particles prepared in advance and then kneading and pelletizing.

In the present invention, the polyolefin particles are subjected to measurement after selectively introducing a staining agent comprising a heavy metal compound into an amorphous part in the polyolefin particles.
The staining agent is not particularly limited as long as it can be fixed to polyolefin particles and can reflect X-rays, but is selected from those consisting of osmium tetroxide (OsO ₄ ), ruthenium tetroxide (RuO ₄ ), and phosphotungstic acid. One or more selected from osmium tetroxide and ruthenium tetroxide are preferable, and ruthenium tetroxide is more preferable.

The staining agent can be introduced by selectively depositing heavy metal by an oxidation reaction, a crosslinking reaction, or the like in the amorphous part of the crystalline polymer.
In general, polyolefin is composed of light elements such as C, H, N, O, etc., so it has good X-ray transmission, and it is difficult to obtain a contrast sufficient to recognize the internal structure. By introducing and fixing with a compound, the contrast can be easily improved during X-ray irradiation.

  The method of introducing a dye comprising a heavy metal compound into the amorphous part of the polyolefin particle (dyeing with a dye) is not particularly limited, but it can uniformly penetrate not only the surface of the polyolefin particle but also the internal complex structure. For example, a method of selectively depositing the polyolefin particles in an amorphous part of the polyolefin particles by placing the polyolefin particles in a vapor atmosphere containing a heavy metal compound, or a method of immersing a polyolefin sample in an aqueous solution of a heavy metal compound. A method of depositing in a crystal part, a method of instantly depositing in an amorphous part by disposing polyolefin particles in an atmosphere in which a sublimation gas of a heavy metal compound is converted into plasma are preferable.

  When introducing a dye comprising a heavy metal compound into the amorphous part of the polyolefin particles, the dyeing conditions such as the concentration of the dye used, the treatment time, and the ambient temperature must be sufficiently introduced into the amorphous part of the polyolefin particles. What is necessary is just to select the conditions to obtain suitably.

  In the method for measuring the internal structure of a polyolefin particle according to the present invention, after introducing a stain comprising a heavy metal compound into an amorphous part of the polyolefin particle, the resulting polyolefin particle (selecting a stain comprising a heavy metal compound as the amorphous part) is selected. The introduced polyolefin particles) are measured using an XMCT apparatus.

As shown in FIG. 1, the measurement by the XMCT apparatus is performed by placing the X-ray source (S) and the detector (D) at positions facing left and right or up and down around the sample tube (T) containing polyolefin particles. It is preferable to measure in a state where it is placed and fixed. In this case, the sample tube T containing polyolefin particles is provided on the rotary stage device (R), and irradiated with X-rays (e) while rotating the rotary stage (R), and continuously photographed at various rotational angles ( By performing cross-sectional observation), it is possible to obtain two-dimensional projection data and three-dimensional projection data, reconstruct the obtained projection image data, and obtain a still image or a moving image.
The XMCT apparatus used in the present invention is not particularly limited, but in order to obtain an accurate observation result, an apparatus having a spatial resolution of 10 μm or less and 1 voxel of 2 μm or less is preferable.

  By using the above XMCT apparatus, the polyolefin particles to be measured are composed of amorphous parts, crystal parts and voids of the whole polyolefin particles easily and in a short time without causing thermal damage, cutting or destruction. The three-dimensional distribution information can be obtained, and from the obtained three-dimensional distribution information, the abundance ratio of the amorphous part, the crystal part, and the void part can be calculated simply and accurately.

  According to the present invention, by selectively introducing a staining agent comprising a heavy metal compound into an amorphous part in a polyolefin particle and observing it with XMCT, a polyolefin particle having weak X-ray absorption and a crystal with a small density difference are obtained. 3D distribution information consisting of an amorphous part, a crystalline part and a void part inside the polyolefin particle can be obtained easily and easily without cutting or destroying the polyolefin particle, even when the part and the amorphous part are the object of observation. It is possible to obtain with high accuracy, and from the obtained three-dimensional distribution information, it is possible to accurately calculate internal structure information such as the abundance ratio of amorphous parts, crystal parts and voids inside the particles.

(Example)
EXAMPLES Next, although an Example is given and this invention is demonstrated further more concretely, this invention is not restrict | limited at all by the following examples.
In the following examples, the p-xylene soluble content (XS) indicating the content ratio of the amorphous part in the polymer was measured by the following method.
<Measurement method of p-xylene soluble content (XS)>
By charging 4.0 g of polyolefin particles and 200 ml of p-xylene into a 200 ml eggplant-shaped flask and setting the external temperature to about 150 ° C., which is the boiling point of xylene (about 137 ° C. to 138 ° C.). The polymer was dissolved over 2 hours while maintaining the temperature of p-xylene inside the flask at the boiling point (137 ° C. to 138 ° C.). Thereafter, the liquid temperature was cooled to 23 ° C. over 1 hour, and the insoluble part was separated by filtration.
20 ml of the obtained filtrate was collected in a heat-resistant / solvent-resistant container, p-xylene was distilled off by heating under reduced pressure, and the amount of the residue was measured to obtain XS (mass%).

Example 1
A double-sided tape is attached to the bottom of a glass petri dish, and the content of p-xylene solubles (XS) is 15.0% by mass as polyolefin particles on the surface of the double-sided tape (hereinafter referred to as ethylene-propylene block copolymer). 100% or more of ethylene-propylene copolymer particles having an average particle diameter (D50) of 1350 μm are fixed, and in an inert atmosphere, ruthenium tetroxide 0.5 % Aqueous solution (sold by JEOL Ltd.) is poured into the petri dish until the copolymer particles are immersed in the aqueous solution. Ruthenium was deposited on the amorphous part of the coalesced particles.
Subsequently, the aqueous solution of the Petri dish was removed, and the dyed ethylene-propylene copolymer particles were collected and sufficiently dried. Then, the following measurement conditions were used using an XMCT apparatus (in vitro type MicroCT35 scanner manufactured by SCANCO MEDICAL). Then, the three-dimensional distribution of amorphous parts, crystal parts and voids inside the polyolefin particles was measured, and the abundance ratio of each part was determined from a histogram showing the density distribution inside the polyolefin particles.

<XMCT measurement conditions and analyzer>
XMCT device: In-vitro type MicroCT35 scanner manufactured by SCANCO MEDICAL Authorized distributor: JEOL Ltd. X-ray output: 45kV / 177μA
Measurement time: about 2 hours Integration time: 800 ms
Average Time: 4
Resolution (Voxel Size): 1.8 μm
Sample folder size: Diameter 7mm x Height 40mm
Number of particles: 20 to 100 Analytical apparatus: Itenium rx2660 Workstation made by Hewlett-Packard Company

FIG. 2 shows a three-dimensional image of one cross section of the polyolefin particles obtained by the XMCT measurement.
In the cross section shown in FIG. 2, the black colored portion is the amorphous portion inside the polyolefin particle, the gray colored portion is the same crystal portion, and the white colored portion is the same void portion.
Moreover, the histogram which shows density distribution inside polyolefin particle | grains based on the obtained data was created. The results are shown in FIG.
In the histogram shown in FIG. 3, the horizontal axis represents density, the vertical axis represents X-ray intensity, the whitened portion g on the left side with the lowest density is a void portion, and the bottom of a twin mountain peak adjacent to the void portion g When branched (when splitting to the left and right with the rising portion of the right peak among the twin peaks shown in FIG. 3), the black portion d on the left side of the twin peaks is a crystal part, The content ratio of the amorphous part a was calculated on the assumption that the white-coated portion a on the right side of the twin mountain peak was an amorphous part, and the content ratio of the amorphous part was 15.1% by mass. The measurement using the above XMCT apparatus took about 2 hours for imaging, and several minutes for calculating the content ratio of the amorphous part, but about 1 compared with the measurement time for p-xylene solubles (XS). The content ratio of the amorphous part could be calculated in a time of / 12. The results are shown in Table 1.

(Comparative Example 1)
The measurement was performed in the same manner as in Example 1 except that the XMCT measurement was performed as it was without treating the polyolefin particles with the ruthenium tetroxide aqueous solution (without performing the treatment with the staining agent).
FIG. 4 shows a three-dimensional image of one cross section obtained by the XMCT measurement.
As is clear from the comparison with FIG. 2, in the cross section shown in FIG. 4, almost no amorphous portion shown in black coloration is observed, and the gray colored portion originally showing the crystal portion contains a considerable proportion of amorphous portion. I understand that
In addition, in the cross section shown in FIG. 4, the portion colored in white is a void portion, and the void portion was included in the same proportion as the void portion shown in white color in FIG.
Moreover, the histogram which shows density distribution inside polyolefin particle | grains based on the obtained data was created. The results are shown in FIG.
In the histogram shown in FIG. 5, the whitened portion g on the left side is a void portion, but since a clear twin mountain as shown in FIG. 3 was not observed, the content ratio of the amorphous portion can be calculated. There wasn't.

(Example 2)
As polyolefin particles, instead of ethylene-propylene copolymer particles having a p-xylene soluble content (XS) of 15.0 mass%, a block ratio of 21.5 mass%, and an average particle diameter (D50) of 1350 μm, p -Example 1 except that ethylene-propylene copolymer particles having a xylene-soluble content (XS) of 10.3 mass%, a block ratio of 14.7 mass%, and an average particle size (D50) of 2100 µm were used. Similarly, the XMCT measurement was performed, and the content ratio of the amorphous part was calculated. By using the XMCT apparatus, the content ratio of the amorphous part could be calculated in about 1/12 of the XS measurement time.
FIG. 6 shows a three-dimensional image of one cross section of the polyolefin particles obtained by the XMCT measurement, and Table 1 shows the content ratio of the amorphous part.

(Example 3)
As polyolefin particles, instead of ethylene-propylene copolymer particles having a p-xylene soluble content (XS) of 15.0 mass%, a block ratio of 21.5 mass%, and an average particle diameter (D50) of 1350 μm, p -Example 1 except that ethylene-propylene copolymer particles having a xylene soluble content (XS) of 8.5 mass%, a block ratio of 27.1 mass%, and an average particle size (D50) of 735 µm were used. Similarly, the XMCT measurement was performed, and the content ratio of the amorphous part was calculated. By using the XMCT apparatus, the content ratio of the amorphous part could be calculated in about 1/12 of the XS measurement time.
FIG. 7 shows a cross section of the polyolefin particles obtained by the XMCT measurement as a three-dimensional image, and Table 1 shows the content ratio of the amorphous part.

Example 4
As polyolefin particles, instead of ethylene-propylene copolymer particles having a p-xylene soluble content (XS) of 15.0 mass%, a block ratio of 21.5 mass%, and an average particle diameter (D50) of 1350 μm, p -Example 1 except that ethylene-propylene copolymer particles having a xylene-soluble content (XS) of 0.10% by mass, a block rate of 0.19% by mass, and an average particle size (D50) of 295 μm were used. Similarly, the XMCT measurement was performed, and the content ratio of the amorphous part was calculated. By using the XMCT apparatus, the content ratio of the amorphous part could be calculated in about 1/12 of the XS measurement time. Table 1 shows the content ratio of the obtained amorphous part.

(Example 5)
As polyolefin particles, instead of ethylene-propylene copolymer particles having a p-xylene soluble content (XS) of 15.0 mass%, a block ratio of 21.5 mass%, and an average particle size (D50) of 1350 μm, Except for using ethylene-propylene copolymer polymer particles having a p-xylene-soluble content (XS) of 50.3% by mass, a block ratio of 62.5% by mass, and an average particle size (D50) of 3050 μm. XMCT measurement was performed in the same manner as in Example 1, and the content ratio of the amorphous part was calculated. By using the XMCT apparatus, the content ratio of the amorphous part could be calculated in about 1/12 of the XS measurement time. Table 1 shows the content ratio of the obtained amorphous part.

2, 4, 6, and 7, in Examples 1 to 5, polyolefin particles in which a dyeing agent composed of a heavy metal compound is selectively introduced into an amorphous part are measured by XMCT as polyolefin particles. Thus, even when polyolefin particles having a small density difference between the crystal part and the amorphous part and having a weak X-ray absorption are measured, while suppressing damage to the polyolefin particles during measurement, It can be seen that the three-dimensional distribution of the amorphous part, the crystal part and the void part can be measured easily and accurately.
Moreover, it can be seen from Table 1 and the like that the value equivalent to that of the conventional method (XS method) can be easily and accurately measured as the abundance ratio of the amorphous portion by XTCT measurement without destroying the polyolefin particles.

  On the other hand, from FIG. 4, in Comparative Example 1, since the polyolefin particles into which the staining agent made of a heavy metal compound is not introduced are used as the measurement object, the amorphous and crystalline parts inside the polyolefin particles are identified. It was not possible to measure the existence ratio of the amorphous part.

  According to the present invention, as polyolefin particles, polyolefin particles in which a dyeing agent comprising a heavy metal compound is selectively introduced into an amorphous part are measured by XMCT, so that the density difference between the crystalline part and the amorphous part is small. Even when polyolefin particles that are weakly absorbed are measured, while suppressing damage to the polyolefin particles during measurement, the three-dimensional distribution of amorphous parts, crystal parts and voids inside the polyolefin particles and the existence of each part It is possible to provide a method for measuring the internal structure information such as the ratio easily and accurately.

Claims (4)

  A method for measuring the internal structure of a polyolefin particle, characterized in that polyolefin particles into which a staining agent comprising a heavy metal compound is selectively introduced into an amorphous part are measured using X-ray microcomputer tomography.   The method for measuring the internal structure of polyolefin particles according to claim 1, wherein the heavy metal compound is ruthenium tetrachloride.   The interior of the polyolefin particle according to claim 1 or 2, wherein the polyolefin particle contains polypropylene or a propylene-α-olefin copolymer containing ethylene or an α-olefin having 4 to 8 carbon atoms. Structure measurement method.   The method for measuring the internal structure of polyolefin particles according to any one of claims 1 to 3, wherein the polyolefin particles contain 0.05 to 70% by mass of an ethylene-propylene copolymer.