JP2022095438A - Method for observing polymer composition - Google Patents

Abstract

To provide a method for observing a surface of a polymer composition without being affected by a bleed component and/or a bloom component in the polymer composition.SOLUTION: The present invention relates to a method for observing a phase structure of a polymer composition that includes a bleed composition and/or a bloom composition. The method includes a step (1) of cutting the polymer composition out as a thin piece; a step (2) of putting the cut-out thin piece on a smooth substrate; and a step (3) of observing the thin piece on the substrate by an atomic force microscope.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method of observing a polymer unaffected by bleed and / or bloom components in the polymer.

In recent years, in the development of polymer materials, it has become important to image and observe the phase structure of a polymer and the phase structure of a polymer and a compound.

Most polymer compositions have a phase structure consisting of phases sized from a few nm to a few hundred μm. The size and arrangement of each phase is complex and diverse because it is affected by the composition of the polymer composition, especially the additives such as reinforcing agents and colorants contained in the polymer composition, and the thermal history of the polymer composition. A phase structure is formed. Since the phase structure also affects the physical properties of the polymer composition, accurate observation of the phase structure is an indispensable technique for the development of polymer materials.

Conventionally, as a method for observing the phase structure of a polymer composition as an image, a transmission electron microscope (TEM), a scanning electron microscope (SEM), an atomic force microscope (AFM), and the like have been used. Among them, AFM has the same resolution as TEM and is excellent in that it can be observed in the presence of air and in water. Examples of the method for observing the phase structure by AFM include Patent Documents 1 and 2.

Patent Document 1 proposes a method of forming a plurality of phases having different hardness by performing deterioration treatment before observing the phase structure by AFM and observing the phase structure of the blend polymer more clearly.

Patent Document 2 proposes a method in which a hydrophilic bleed component and / or a bloom component in a polymer is removed from the polymer by extracting the polymer with an amphipathic solvent, and then the polymer is observed.

Japanese Unexamined Patent Publication No. 2014-19883 Japanese Unexamined Patent Publication No. 2017-129542

In the measurement by AFM, it is necessary to prepare a smooth measurement surface on the sample surface by using a microtome or the like. However, when the sample contains a component that easily bleeds and / or blooms, there is a problem that the measurement surface is covered with the bleed component and / or the bloom component, which makes the desired observation difficult. As a solution, there are methods such as performing Soxhlet extraction using an organic solvent such as acetone as a pretreatment for observation, or performing observation in water that makes it difficult to bleed and / or bloom.

If the bleed component and / or the bloom component is hydrophobic, most of it can be removed with an organic solvent such as acetone, and bleed and / or bloom can be suppressed by performing an extraction treatment before observation. Also, if observation in water is possible, this can suppress bleeding and / or blooming of hydrophobic components. However, if hydrophilic bleed and / or bloom components are contained, it is difficult to remove them with an organic solvent such as acetone, and bleed and / or bloom is promoted during observation in water. There is a problem that it becomes difficult to observe.

In the method of extracting and observing with an amphipathic solvent of Patent Document 2, the bleed component and / or the bloom component in the polymer is removed, so that the polymer cannot be observed in the state of containing the bleed component and / or the bloom component. There's a problem. In material development, it may be necessary to observe the polymer surface in a state containing bleed components and / or bloom components, and it is assumed that the extraction process may be a problem.

In the present invention, the polymer composition contains a bleed component and / or a bloom component in the polymer without being subjected to an extraction treatment of the polymer composition, and is not affected by the bleed component and / or the bloom component in the polymer. It is intended to provide a method of observing the surface of a polymer.

As a result of diligent studies, the present inventor made a thin section of the polymer composition and placed it on a highly smooth substrate when observing the phase structure of the polymer composition with an atomic force microscope (AFM). It was found that the phase structure of the polymer composition could be observed without being affected by the bleed component and / or the bloom component in the polymer composition, and further studies were carried out to complete the present invention.

That is, the present invention
[1] A method for observing the phase structure of a polymer composition.
The polymer composition comprises a bleed component and / or a bloom component.
(1) A step of cutting out the polymer composition as a thin section (2) A step of placing the cut out thin section on a smooth substrate (3) A step of observing the thin section placed on the substrate with an atomic force microscope. , Observation method,
[2] The observation method according to [1] above, wherein the thickness of the flakes is 1 μm to 5 μm.
[3] The observation method according to the above [1] or [2], wherein the smooth substrate is selected from the group consisting of a silicon wafer, mica and sapphire.
[4] The observation method according to any one of the above [1] to [3], wherein the observation in the step (3) is an observation in the tapping mode or the force volume mode of the atomic force microscope.
[5] The observation method according to any one of [1] to [4] above, wherein the step (1) and the step (3) are carried out at intervals of 30 minutes or more.

According to the present invention, the surface of the polymer composition can be observed without being affected by the bleed component and / or the bloom component in the polymer composition.

6 is an AFM image immediately after preparation of the observation sample of the example. It is an AFM image immediately after preparation of the observation sample of a comparative example. 8 is an AFM image 24 hours after the preparation of the observation sample of the example. It is an AFM image 24 hours after preparation of the observation sample of a comparative example.

The present disclosure is a method for observing the phase structure of a polymer composition, wherein the polymer composition contains a bleed component and / or a bloom component, and a step of cutting out the polymer composition as flakes and the cut out flakes are cut out. It is an observation method including a step of placing it on a smooth substrate and a step of observing the flakes placed on the substrate with an atomic force microscope.

Without being bound by theory, the phase structure observation method of the present disclosure allows the surface of the polymer composition to be observed without being affected by the bleed component and / or the bloom component in the polymer composition. The following can be considered as the mechanism. That is, in the phase structure observation method of the present disclosure, since the section of the polymer composition to be observed is made into flakes, the absolute amount of the bleed component and / or the bloom component in the flakes can be reduced. Further, by placing the flakes on a smooth substrate, the cut surface of the flakes can be kept stable in a state where they can be observed by AFM. As a result, it is considered that the polymer surface can be observed without being affected by the bleed component and / or the bloom component in the polymer composition.

The thickness of the flakes is preferably 1 μm to 5 μm.

The smooth substrate is preferably selected from the group consisting of silicon wafers, mica and sapphire.

The observation in the observation step is preferably an observation in the tapping mode or the focus volume mode of an atomic force microscope (AFM).

It is preferable that the step (1) and the step (3) are carried out at intervals of 30 minutes or more.

<Polymer composition>
The polymer composition that can be observed by the present disclosure is not particularly limited as long as it is a polymer composition forming a phase structure and contains a bleed component and / or a bloom component. Further, the polymer composition may contain a filler, or may further contain a compounding agent other than the filler. Further, the polymer composition may be an unvulcanized product or a vulcanized product. Of these, a vulcanized product is preferable. As used herein, the term "polymer" refers to a polymer having a weight average molecular weight of 10,000 or more, preferably a weight average molecular weight of 100,000 or more, more preferably a weight average molecular weight of 200,000 or more, and further preferably a weight average molecular weight of 300,000. That is all. The type of the monomer constituting the polymer may be one kind or two or more kinds.

(Polymer component)
The polymer constituting the polymer component is not particularly limited, and is, for example, polyethylene, polypropylene, polybutadiene, polyisoprene, ethylene-propylene copolymer, polystyrene, styrene-butadiene copolymer, acrylonitrile-styrene copolymer, poly. Various polymers such as vinyl chloride, polyacrylic acid, polymethacrylic acid, polyamide, polyurethane, polyethylene terephthalate, polybutylene terephthalate, polytetrafluoroethylene, polycarbonate, polysulfone, polyethersulfone, epoxy resin, urethane resin, unsaturated polyester resin, etc. Various resins, modified natural rubber such as natural rubber (NR), epoxidized natural rubber (ENR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene-isoprene-butadiene rubber ( SIBR), styrene-isoprene rubber, isoprene-butadiene rubber, acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR) and other diene rubbers, butyl rubber (IIR), ethylene-propylene rubber (EPM), urethane rubber (U). , Silicone rubber (Q), chlorosulfonated polyethylene (CSM), chlorinated polyethylene, acrylic rubber (ACM), epichlorohydrin rubber (CO, ECO), fluororubber (FKM) and other non-diene rubbers. These polymers may be used alone or in combination of two or more. In the examples of the present application, styrene butadiene rubber (SBR) was used.

(Bleed component, Bloom component)
In the present disclosure, the bleed component or the bloom component is a component contained in the polymer composition, and is a component that exudes from the inside of the molded body to the surface with the lapse of time after molding the polymer composition. The bleed component or the bloom component may contain one kind alone or two or more kinds. The bleed component or bloom component is not particularly limited as long as it is a component that exudes as described above, but more specifically, an antiaging agent, an oil, a wax, a plasticizer, which is generally used in a polymer composition. Examples include compounding agents such as colorants.

The antiaging agent is not particularly limited, and examples thereof include amine-based, quinoline-based, quinone-based, phenol-based, and imidazole-based compounds, and antiaging agents such as carbamate metal salts. -(1,3-Dimethylbutyl) -N'-phenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N, N' -Phenylenediamine-based antiaging agents such as di-2-naphthyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, and 2,2,4-trimethyl-1,2-dihydroquinoline weight. Phenylene-based antioxidants such as coalesced, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinolin are preferred. These anti-aging agents may be used alone or in combination of two or more. When the antioxidant is contained, the content of the polymer component with respect to 100 parts by mass is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more from the viewpoint of ozone crack resistance. From an economic point of view, 10 parts by mass or less is preferable, and 5 parts by mass or less is more preferable.

Examples of the oil include process oils, vegetable oils and fats, animal oils and fats and the like. Examples of the process oil include paraffin-based process oils, naphthen-based process oils, aromatic process oils and the like. Further, as an environmental measure, a process oil having a low content of a polycyclic aromatic compound (PCA) compound can also be used. Examples of the low PCA content process oil include mild extraction solvates (MES), treated distillates aromatic extracts (TDAE), heavy naphthenic oils and the like. The oil may be used alone or in combination of two or more. When oil is contained, the content of the polymer component with respect to 100 parts by mass is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 3 parts by mass or more, from the viewpoint of processability. From an economic point of view, 60 parts by mass or less is preferable, 30 parts by mass or less is more preferable, and 10 parts by mass or less is further preferable.

The wax is not particularly limited, and any commonly used wax can be used, and the content thereof is preferably 0.5 part by mass or more with respect to 100 parts by mass of the polymer component from the viewpoint of weather resistance. 1 part by mass or more is more preferable. From an economic point of view, 10 parts by mass or less is preferable, and 5 parts by mass or less is more preferable.

The plasticizer is not particularly limited, and any commonly used plasticizer can be used, for example, dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), diazeline acid. 2-ethylhexyl (DOZ), dibutyl sebacate (DBS), diisononyl adipate (DINA), diethyl phthalate (DEP), dioctyl phthalate (DOP), diundecyl phthalate (DUP), dibutyl phthalate (DBP), sevacin Dioctyl Acid (DOS), Tributyl Phosphate (TBP), Trioctyl Phosphate (TOP), Triethyl Phosphate (TEP), trimethyl Phosphate (TMP), Timidin Triphosphate (TTP), Tricresyl Phosphate (TCP), Phosphate Examples thereof include ester-based plasticizers such as trixylenyl (TXP). The plasticizer may be used alone or in combination of two or more. The content of the plasticizer is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and further preferably 3 parts by mass or more with respect to 100 parts by mass of the polymer component. The content of the plasticizer is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 10 parts by mass or less.

The colorant is not particularly limited, and any commonly used colorant can be used, and the content thereof is preferably 0.5 part by mass or more with respect to 100 parts by mass of the polymer component, and 1 part by mass or more. Is more preferable. From an economic point of view, 10 parts by mass or less is preferable, and 5 parts by mass or less is more preferable.

(Filler)
The filler is not particularly limited, and examples thereof include fillers generally used in the production of rubber compositions and the like, such as carbon black and silica. Examples of the filler other than silica and carbon black include aluminum hydroxide, calcium carbonate, alumina, clay, talc and the like.

The carbon black is not particularly limited, and examples thereof include carbon black generally used in the production of rubber compositions and the like, and examples thereof include carbon black such as furnace black, acetylene black, thermal black, channel black, and graphite. Alternatively, examples of the carbon black include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. These carbon blacks may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of the carbon black is preferably 50 m ² / g or more, more preferably 70 m ² / g or more, still more preferably 90 m ² / g or more. The N ₂ SA is preferably 400 m ² / g or less, more preferably 200 m ² / g or less, and even more preferably 150 m ² / g or less. Within the above range, the effect tends to be more preferably obtained. The carbon black N ₂ SA is a value measured by JIS K6217-2: 2001.

The silica is not particularly limited, and examples thereof include silica generally used for producing rubber compositions and the like, for example, silica prepared by a dry method, silica prepared by a wet method, and the like. Of these, hydrous silica prepared by a wet method is preferable because it has a large number of silanol groups. These silicas may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of the silica is preferably 80 m ² / g or more, more preferably 90 m ² / g or more, and further preferably 100 m ² / g or more. The N ₂ SA is preferably 500 m ² / g or less, more preferably 300 m ² / g or less, and further preferably 200 m ² / g or less. Within the above range, the effect tends to be more preferably obtained. The N ₂ SA of silica is a value measured by the BET method according to ASTM D3037-81.

The average particle size of the silica is preferably 50 nm or less, more preferably 30 nm or less, still more preferably 25 nm or less. The lower limit of the average particle size of the silica is preferably 13 nm or more, more preferably 15 nm or more, and further preferably 18 nm or more. The average particle size of silica is a number average particle size of particles in an arbitrary field, and is measured by a transmission electron microscope.

The total content of carbon black and silica is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, based on 100 parts by mass of the polymer component, from the viewpoint that the morphology of the polymer can be observed without being covered with these fillers. It is more preferably 30 parts by mass or less, still more preferably 20 parts by mass or less. On the other hand, the lower limit of the content is not particularly limited and may be 0 parts by mass, but may be more than 0 parts by mass, 5 parts by mass or more, or 10 parts by mass or more. ..

(Compounding agent)
The compounding agent is not particularly limited, and commonly used ones can be used, and examples thereof include a silane coupling agent, zinc oxide, stearic acid, a processing aid, a vulcanizing agent, and a vulcanization accelerator. Will be.

The silane coupling agent is preferably used in combination when silica is used. The silane coupling agent is not particularly limited, but for example, a mercapto-based silane coupling agent; a sulfide-based silane coupling agent such as bis (3-triethoxysilylpropyl) disulfide and bis (3-triethoxysilylpropyl) tetrasulfide. Agents: Vinyl-based silane coupling agents such as vinyltriethoxysilane and vinyltrimethoxysilane; 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane and the like. Amino-based silane coupling agents; γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane and other glycidoxy-based silane coupling agents; 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxy. Nitro-based silane coupling agents such as silane; chloro-based silane coupling agents such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane can be mentioned. These silane coupling agents may be used alone or in combination of two or more. The content of the silane coupling agent with respect to 100 parts by mass of silica (total amount of all silane coupling agents when used in combination) is preferably 1.0 part by mass or more from the viewpoint of enhancing the dispersibility of silica. .0 parts by mass or more is more preferable, and 5.0 parts by mass or more is further preferable. Further, from the viewpoint of cost and workability, 20 parts by mass or less is preferable, 15 parts by mass or less is more preferable, and 12 parts by mass or less is further preferable.

The zinc oxide is not particularly limited, and a commonly used zinc oxide can be used, and the content thereof is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the polymer component from the viewpoint of processability. More than parts by mass is more preferable. From an economic point of view, 10 parts by mass or less is preferable, and 5 parts by mass or less is more preferable.

The stearic acid is not particularly limited, and a commonly used one can be used, and the content thereof is preferably 0.5 part by mass or more with respect to 100 parts by mass of the polymer component from the viewpoint of processability. More than parts by mass is more preferable. From an economic point of view, 10 parts by mass or less is preferable, and 5 parts by mass or less is more preferable.

The processing aid is not particularly limited, and commonly used ones can be used, for example, fatty acid metal salt, fatty acid amide, amide ester, silica surface active agent, fatty acid ester, mixture of fatty acid metal salt and amide ester. , A mixture of fatty acid metal salt and fatty acid amide, and the like. These processing aids may be used alone or in combination of two or more. The content of the processing aid is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more, from the viewpoint of exerting the effect of improving processability with respect to 100 parts by mass of the polymer component. From an economic point of view, 10 parts by mass or less is preferable, and 5 parts by mass or less is more preferable.

The vulcanizing agent is not particularly limited, and commonly used vulcanizing agents can be used. For example, sulfur is preferably used. As the sulfur, powdered sulfur, oil-treated sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur and the like can be used. When sulfur is contained as a vulcanizing agent, the content with respect to 100 parts by mass of the rubber component is preferably 0.1 part by mass or more, more preferably 0.3 parts by mass or more, from the viewpoint of ensuring a sufficient vulcanization reaction. More preferably, 0.5 part by mass or more. From the viewpoint of preventing deterioration, 5.0 parts by mass or less is preferable, 4.0 parts by mass or less is more preferable, and 3.0 parts by mass or less is further preferable. When oil-containing sulfur is used as the vulcanizing agent, the content of the vulcanizing agent is the total content of pure sulfur contained in the oil-containing sulfur. Examples of the vulcanizing agent other than sulfur include alkylphenol / sulfur chloride condensate, 1,6-hexamethylene-sodium dithiosulfate / dihydrate, and 1,6-bis (N, N'-dibenzylthio). Carbamoyldithio) Hexane and the like can be mentioned. As these vulcanizing agents other than sulfur, those commercially available from Taoka Chemical Industry Co., Ltd., LANXESS Co., Ltd., Flexis Co., Ltd. and the like can be used.

The vulcanization accelerator is not particularly limited, and commonly used ones can be used, for example, sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamic acid-based, and aldehyde-amine-based. Alternatively, an aldehyde-ammonia-based, imidazoline-based, or xanthate-based vulcanization accelerator may be used. These vulcanization accelerators may be used alone or in combination of two or more. Examples of the sulfenamide-based vulcanization accelerator include N-tert-butyl-2-benzothiazolyl sulfenamide (TBBS), N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS), N, N. -Dicyclohexyl-2-benzothiazolyl sulfenamide (DCBS) and the like can be mentioned. Of these, N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS) is preferable. Examples of the guanidine-based vulcanization accelerator include 1,3-diphenylguanidine (DPG), 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, and di-o-tolylguanidine salt of dicatecholbolate. , 1,3-di-o-cumenylguanidine, 1,3-di-o-biphenylguanidine, 1,3-di-o-cumenyl-2-propionylguanidine and the like. Of these, 1,3-diphenylguanidine (DPG) is preferable. Examples of the thiazole-based vulcanization accelerator include 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide and the like. Of these, 2-mercaptobenzothiazole is preferable.

From the viewpoint of ensuring fracture strength and elongation, the content of the vulcanization accelerator is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more with respect to 100 parts by mass of the polymer component. The content is preferably 8 parts by mass or less, more preferably 7 parts by mass or less, and further preferably 6 parts by mass or less.

<Manufacturing of polymer composition>
The polymer composition of the present disclosure can be produced by a known method. For example, it can be produced by kneading each of the above components with a kneading machine. As the kneader, any known kneader can be used, and examples of such a kneader include an open roll, a closed kneader (Banbury mixer, a kneader, etc.) and the like.

When producing a vulcanized product containing a vulcanizing agent and a vulcanization accelerator, the kneading step includes, for example, a base kneading step of kneading each component other than the vulcanizing agent and the vulcanization accelerator, and a base. It preferably includes a final kneading (F kneading) step of adding a vulcanizing agent and a vulcanization accelerator to the kneaded product obtained in the kneading step and kneading the kneaded product. Further, the base kneading step can be divided into a plurality of steps, if desired. The kneading conditions are not particularly limited, but for example, in the base kneading step, kneading is performed at a discharge temperature of 140 to 170 ° C. for 3 to 10 minutes, and in the final kneading step, kneading is performed at 70 to 110 ° C. for 1 to 5 minutes. There is a method of kneading. Further, in the base kneading step, the filling rate of the raw material is preferably 50% or more, more preferably 53% or more, still more preferably 56% or more. On the other hand, the filling rate of the raw material is preferably 70% or less, more preferably 65% or less, still more preferably 60% or less. The filling rate of the raw material is a value obtained by dividing the volume of the raw material by the capacity of the kneader. By vulcanizing the kneaded product thus obtained, a vulcanized product can be obtained. The vulcanization conditions are not particularly limited, and examples thereof include a method of vulcanizing at 150 to 200 ° C. for 10 to 30 minutes.

<Phase structure>
In the present disclosure, the phase structure of the polymer composition is a phase structure composed of a plurality of phases having a size of several nm to several hundred μm. The size and arrangement of each phase is affected by the composition of the polymer composition, in particular the additives such as reinforcing agents and colorants contained in the polymer composition, and the thermal history of the polymer composition.

In the polymer composition of the present disclosure, the polymer component may be composed of one kind of polymer or may be a blended polymer containing two or more kinds of incompatible polymers. When the polymer component is a blended polymer containing two or more incompatible polymers, such polymer components form complex and diverse phase structures such as sea-island structures and co-continuous structures. From the viewpoint that the phase structure of the polymer component can be observed, the polymer composition is preferably a blend polymer containing two or more incompatible polymer components, and two or more kinds of which form a sea-island structure. It is more preferable to use a blended polymer containing a polymer component.

Here, incompatible means that different kinds of polymers are difficult to be uniformly mixed at the molecular level. In a blended polymer containing a plurality of mutually incompatible polymers, a phase structure is formed by phase separation of each polymer, and in some cases, a sea-island structure is formed. Specific combinations of polymer components that can form a sea-island structure include combinations of NR and BR, NR and SBR, NR and EPDM, SBR and NBR, and the like.

<Process of cutting out as flakes>
In the present disclosure, the flakes can be prepared by cutting out from a mass of a polymer composition by a conventional method. The thickness of the flakes may vary depending on the hardness, viscosity, composition, etc. of the polymer composition, but is within the thickness range in which observation of the surface of the polymer composition can be achieved without being affected by the bleed component and / or the bloom component. There are no particular restrictions. If the thickness of the flakes is too thin, the cut pieces tend to be curled up, making it difficult to move them to the substrate. Further, in the observation in the force volume mode of the AFM, the influence of the hardness of the substrate is strongly exerted, so that the measurement tends to be difficult. On the other hand, if the thickness of the slice is too thick, the load on the instrument at the time of cutting tends to be large. Further, the absolute amount of the bleed component and / or the bloom component tends to be large, and the effect of suppressing the bleed and / or the bloom tends to be small.

The thickness of the flakes is usually preferably 0.5 μm or more, more preferably 0.7 μm or more, further preferably 0.9 μm or more, still more preferably 1.0 μm or more. On the other hand, the thickness of the flakes is preferably 10 μm or less, more preferably 8 μm or less, still more preferably 5 μm or less. In the examples of the present application, the polymer composition was cut out to a thickness of 1 μm.

In the present disclosure, the slices can be cut out by a conventional method. For example, first, the polymer composition for cutting out the flakes is preformed into a shape that is easy to cut out. Knives, scissors, razors and the like are appropriately used for molding the polymer composition. Next, flakes are cut out from the molded polymer composition. The shape and size of the slices cut out in this way are not particularly limited as long as the thickness is within the above range and the remainder can be installed on the AFM sample table. Although the slices can be cut out by a conventional method, a cryomicrotome or the like can be preferably used. Cryomicrotome is a method in which a material to be cut is frozen in advance and then slices are cut out from the frozen material using a razor or a cryostat. A smooth surface can be formed on the flakes cut out by the cryomicrotome. The smooth surface thus obtained is suitable for observation by AFM.

<Process of placing the cut pieces on a smooth substrate>
The cut pieces can be placed on a smooth substrate by sandwiching them with a tool such as tweezers and moving them onto a smooth substrate.

The surface smoothness Ra of the smooth substrate is preferably 100 nm or less, more preferably 50 nm or less, still more preferably 50 nm or less, from the viewpoint that the unevenness or inclination of the surface does not affect the observation result. It is 40 nm or less, more preferably 30 nm or less, still more preferably 20 nm or less. The lower limit of the surface smoothness Ra is not particularly limited, and the smaller it is, the more preferable it is, but it is usually 10 nm or more. Ra in the present specification is a value measured by a laser microscope.

The material of the smooth substrate is not particularly limited, and for example, a silicon wafer, mica, or sapphire can be preferably used. Of these, a silicon wafer is preferable from the viewpoint of high smoothness.

<Process of observing flakes placed on the substrate with AFM>
The flakes placed on the substrate can be observed with an atomic force microscope (AFM) by a conventional method.

The AFM is equipped with a cantilever having a probe attached to the tip thereof, and the probe scans the surface of the sample piece, and the movement of the probe is detected by the cantilever. An AFM image is obtained by imaging the movement of the probe detected by the cantilever. With AFM, it is possible to measure the three-dimensional shape of the surface of the sample piece and the mechanical characteristics such as the hardness and frictional force of the surface of the sample piece. Suitable AFMs in the observation method of the present disclosure include MultiMode8 manufactured by Bruker AXS, E-sweep manufactured by Hitachi High-Tech Science Corporation, and the like. Measurement conditions such as the spring constant of the cantilever are appropriately selected according to the type and surface condition of the sample piece. As the probe, tungsten, iridium, silicon nitride or the like can be used as a material.

The AFM observations of the present disclosure are observed in the appropriate measurement mode provided by the AFM. The appropriate measurement mode is appropriately selected depending on the type of the polymer component contained in the polymer composition and the surface condition of the sample piece to be subjected to AFM observation. Typical measurement modes of AFM include contact mode, tapping mode, non-contact mode, force volume mode and the like. Preferred measurement modes are a tapping mode for detecting a phase difference and a force volume mode in which a mechanical response can be obtained at individual measurement points.

According to the observation method of the present disclosure, the step of observing with AFM from the step of cutting out the polymer composition is, for example, 30 minutes or more, further 1 hour or more, further 6 hours or more, further 12 hours or more, and further. Even when carried out at intervals of 18 hours or more, and even 24 hours or more, it can be observed without being affected by the bleed component and / or the bloom component in the polymer. In the case of a polymer composition having a composition susceptible to bleeding components and / or blooming components, such as containing a large amount of oil, bleeding and / or blooming can occur even in about 30 minutes. In the case of a polymer composition having a general formulation, it can bleed and / or bloom even for about 12 hours.

Further, according to the phase structure observation method of the present disclosure, even a sample containing a hydrophilic bleed component and / or a bloom component, which has been difficult to observe in water in the past, can be sliced. As it is, the phase structure of the polymer can be observed without being affected by the bleed component and / or the bloom component in the polymer.

The present disclosure will be described based on examples, but the present disclosure is not limited to the examples.

The various chemicals used in Examples and Comparative Examples are summarized below.
SBR: Nippon Zeon Co., Ltd. Nippon 1502
Silica: ZEOSIL 115GR manufactured by Rhodia Japan Co., Ltd. (N ₂ SA: 110 m ² / g, average primary particle size: 20 nm)
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by EVONIC INDUSTRIES.
Oil: Process X-140 manufactured by Japan Energy Co., Ltd.
Zinc oxide: Ginmine R manufactured by Toho Zinc Co., Ltd.
Stearic acid: Tsubaki wax manufactured by NOF Corporation: Ozoace 0355 manufactured by NOF Corporation
Anti-aging agent: Nocrack 6C (N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
Sulfur: 5% oil-treated powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. (soluble sulfur containing 5% by mass of oil)
Vulcanization accelerator: Noxeller NS (N-tert-butyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.

<Preparation of vulcanized rubber composition>
According to the compounding formulation of step 1 in Table 1, various chemicals were filled in a 1.7 L vanbury manufactured by Kobe Steel, Ltd. so that the filling rate was 58%, and kneaded until the temperature reached 140 ° C. Sulfur and a vulcanization accelerator were added to the obtained kneaded product according to the compounding formulation of step 2 in Table 1, and further kneaded until the temperature reached 80 ° C. to obtain an unvulcanized rubber composition. Then, the obtained unvulcanized rubber composition was molded and vulcanized at 160 ° C. for 20 minutes to obtain each vulcanized rubber composition.

<Preparation of observation sample>
From the vulcanized rubber composition obtained above, a small piece (vertical: about 2 mm, horizontal: about 3 mm, height: about 2 mm) is cut out using a razor, and further, from the small piece, a thickness of 1 μm is obtained by a cryomicrotome. A thin section was cut out. The flakes thus obtained were placed on a silicon wafer substrate (6inc4H-N350 μm manufactured by Trinity Co., Ltd.) and used as an observation sample in Examples. On the other hand, the sample was placed on a silicon wafer substrate so that the surface of the main body, which was exposed by cutting out, was facing up, and used as an observation sample in the comparative example.

<Observation by AFM and bleed and bloom evaluation>
Immediately after the sample preparation and the next day (24 hours after the sample preparation), the observation sample in the example and the observation sample in the comparative example were subjected to AFM (MultiMode8 manufactured by Bruker Japan Co., Ltd., tapping mode measurement, measurement environment: in the air, Observation was performed with a cantilever: 40 N / m (SI-DF40 manufactured by Olympus Co., Ltd.), frequency: 10 Hz, measurement range: 2 μm × 2 μm). The observation results immediately after the sample preparation are shown in FIGS. 1 (Example) and 2 (Comparative Example), and the observation results on the day after the sample preparation are shown in FIGS. 3 (Example) and 4 (Comparative Example).

Immediately after sample preparation, the phase structure can be observed in both Example (FIG. 1) and Comparative Example (FIG. 2). However, in Example 1 in which the thin section is used, a more detailed phase structure can be observed.

On the other hand, on the day after sample preparation, the phase structure of the polymer surface could be observed in the example (FIG. 3) without being affected by the bleed component and / or the bloom component, but in the comparative example (FIG. 4), the bleed component and / or the bloom component were observed. / Or due to the influence of the bloom component, the phase structure of the polymer surface cannot be observed correctly.

From the above observation results, it can be seen that according to the phase structure observation method of the present disclosure, the polymer surface can be observed without being affected by the bleed component and / or the bloom component of the polymer composition.

Claims (5)

A method for observing the phase structure of a polymer composition.
The polymer composition comprises a bleed component and / or a bloom component.
(1) A step of cutting out the polymer composition as a thin section (2) A step of placing the cut out thin section on a smooth substrate (3) A step of observing the thin section placed on the substrate with an atomic force microscope. , Observation method. The observation method according to claim 1, wherein the thickness of the flakes is 1 μm to 5 μm. The observation method according to claim 1 or 2, wherein the smooth substrate is selected from the group consisting of a silicon wafer, mica, and sapphire. The observation method according to any one of claims 1 to 3, wherein the observation in the step (3) is an observation in the tapping mode or the force volume mode of the atomic force microscope. The observation method according to any one of claims 1 to 4, wherein the step (1) and the step (3) are carried out at intervals of 30 minutes or more.

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