JP2018021109A - Rubber member and method for producing the same, and tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber member capable of improving on-ice performance of a rubber article when the rubber member is used for a rubber article such as a tire.SOLUTION: There is provided a rubber member having a nano-substance having a long diameter of less than 100 nm when being in a non-fibrous state or has a minor axis length of less than 100 nm and a major axis length of less than 1000 nm when being in a fibrous state, wherein a plurality minute recesses exist on the surface of the rubber member, the nano-substance is arranged on the inner surface of the minute recesses and the average coverage on the inner surface of the minute recesses is 10% or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rubber member, a manufacturing method thereof, and a tire.

  Since the spike tire was regulated, various studies have been made to improve the braking performance and driving performance of the tire on an icy and snowy road surface. For example, in Japanese Patent Application Laid-Open No. 2014-227487 (Patent Document 1), a modified natural rubber in which a non-rubber component is removed to be highly purified and the pH of the rubber component is adjusted to a predetermined range by treatment with an acidic compound Further, it has been proposed that by using a filler such as carbon black, the reinforcing property can be improved and the performance on ice required for the studless tire can be improved.

JP 2014-227487 A

  However, the above-mentioned conventional technology aims to control the molecular weight during storage by adjusting the pH of the rubber component, and therefore there is a limit to drastically improving the on-ice performance of the tire. is there.

  Then, the objective of this invention is providing the rubber member which can improve the on-ice performance of a rubber article, when it is used for rubber articles, such as a tire. Moreover, the objective of this invention is also providing the manufacturing method of a rubber member which can obtain the rubber member which can improve the on-ice performance of rubber articles, such as a tire. Another object of the present invention is to provide a tire having improved performance on ice.

  In other words, the rubber member of the present invention has a major axis of less than 100 nm when it is non-fibrous, or a minor axis of less than 100 nm and a major axis of less than 1000 nm when it is fibrous. A rubber member having a substance, wherein a plurality of minute recesses exist on the surface of the rubber member, and the nanomaterial is disposed on an inner surface of the minute recess, and the inner part of the minute recess The average coverage of the nano material on the surface is 10% or more. According to the rubber member of the present invention, when used in a rubber article such as a tire, it is possible to improve the on-ice performance of the rubber article.

  The rubber member of the present invention further includes a plurality of microcavities, the nanomaterial is also disposed on the inner surface of the microcavity, and a foaming agent and a non- Nanomaterial-containing organics containing nanomaterials and resins having a major axis of less than 100 nm when fibrous, or a minor axis length of less than 100 nm and a major axis length of less than 1000 nm when fibrous It can be suitably manufactured using a rubber composition formed by blending fibers. The rubber member produced using the above rubber composition can provide high performance on ice for a tire or the like over a long period of time, and does not require an excessive amount of nanomaterial.

  In the rubber member of the present invention, it is preferable that the nanomaterial is disposed on the inner surface of the minute recess by coating, spraying or impregnation. In such a rubber member, more nanomaterials are arranged on the inner surface of the minute recess, and the performance on ice in the initial use of a tire or the like can be greatly improved.

  The method for producing a rubber member according to the present invention is a method for producing a rubber member as described above, wherein the minute diameter formed on the surface of the vulcanized rubber is non-fibrous, and the major axis is less than 100 nm, Alternatively, the method includes a step of providing a nanomaterial having a minor axis length of less than 100 nm and a major axis length of less than 1000 nm when it is fibrous. According to the method for producing a rubber member of the present invention, a rubber member capable of improving the performance on ice of rubber articles such as tires can be obtained. In addition, in this manufacturing method, the nanomaterial can be easily arranged on the inner surface of the microrecessed portion than the case where the nanomaterial is arranged by blending, and the nanomaterial can be easily disposed on the inner surface of the microrecessed portion. The amount can be controlled.

  The tire according to the present invention includes the above-described rubber member in a tread portion. According to the tire of the present invention, the performance on ice is improved.

  ADVANTAGE OF THE INVENTION According to this invention, when used for rubber articles, such as a tire, the rubber member which can improve the performance on ice of a rubber article can be provided. Moreover, according to this invention, the manufacturing method of a rubber member which can obtain the rubber member which can improve the performance on ice of rubber articles, such as a tire, can be provided. Furthermore, according to the present invention, a tire with improved performance on ice can be provided.

It is a schematic cross section showing the surface vicinity of the tread part of an example tire as one embodiment of the rubber member of the present invention. It is a schematic cross section showing the surface and the inside of the tread part of an example tire as one embodiment of the rubber member of the present invention. It is a figure which shows typically the image by SEM of the surface of the rubber member of one comparative example. It is a figure which shows typically the image by SEM of the surface of the rubber member of one Embodiment of this invention. It is a figure which shows typically the image by SEM of the surface of the rubber member of another one Embodiment of this invention.

(Rubber member)
Below, the rubber member of this invention is illustrated and demonstrated in detail based on the one embodiment.
The tread portion 1 of an example tire as an embodiment of the rubber member of the present invention shown in FIG. 1 can be manufactured using a rubber composition containing a rubber component and other optional components, A plurality of minute recesses 2 are present on the surface, and nanomaterials 3 are arranged on the inner surface of each minute recess 2.

  In general, when a vehicle travels on an icy and snowy road surface, a water film is generated due to frictional heat between the icy and snowy road surface and the tire, and this water film reduces the coefficient of friction between the tire and the icy and snowy road surface. It is said that it causes the performance on ice to deteriorate. In this regard, since the rubber member of the example of the present invention has a plurality of minute recesses on the surface, the minute recesses function as drainage grooves, and the friction coefficient between the tire and the icy and snowy road surface by removing the water film. Can be suppressed. Furthermore, the rubber member according to an example of the present invention not only has minute recesses on the surface, but also has a nano material disposed on the inner surface of the recess, so that the surface roughness of the rubber member is substantially increased. Thus, the on-ice performance of the tire can be greatly improved. Here, as a more specific action of improving the performance on ice of a tire or the like by the rubber member of the present invention, it is not certain, but (1) the nanomaterial is dispersed in the water that has entered the minute recesses, and the water (2) Since the rubber component is extremely hydrophobic, more water can be infiltrated into the minute recesses where nanomaterials exist. (3) Nanomaterials can tear the water film and further enhance the function as a drainage groove. (4) The scratching effect of nanomaterials that can come into contact with the snowy and snowy road surface can be considered.

Here, in the present invention, the “micro-recess” is a recess existing on the surface of the rubber member as shown in FIG. 1 and has a maximum depth (D _max ) of 1 to 500 μm, and the rubber member The longest diameter (L _max ) in the developed view of the surface of the surface is in the range of 1 to 500 μm. Accordingly, the “micro-recesses” include those having various outer shapes. The presence / absence of this “micro-recess” can be confirmed from, for example, a photograph of the surface of the rubber member taken with an electron microscope.

In the present invention, the “major axis” of a nanomaterial is a term used when the nanomaterial has a shape other than a fibrous shape (non-fibrous), and connects two arbitrary points on the outer surface of the nanomaterial. It shall indicate the length of the longest straight line. The “major axis” of the nanomaterial can be obtained, for example, by photographing the nanomaterial with an electron microscope.
In the present invention, the “minor axis length” and “major axis length” of the nanomaterial are terms used when the nanomaterial is fibrous, for example, by photographing the nanomaterial with an electron microscope, Can be sought.
In the present specification, “fibrous” means that the aspect ratio obtained by photographing with an electron microscope is more than 1, and “non-fibrous” means fibrous. It shall mean that it is a shape other than.

  Furthermore, in the present invention, the aspect in which the nanomaterial is “arranged” on the inner surface of the minute recess or the like includes an aspect in which the nanomaterial is firmly fixed to the inner surface of the minute recess or the like. Both are included. However, it is preferable that the nanomaterial is not firmly fixed to the inner surface such as a minute recess.

  In FIG. 1, nanomaterials 3 are arranged on the inner surfaces of all the illustrated micro-recesses 2, but the rubber material according to an example of the present invention has a nanomaterial that is used as an external factor such as a road surface. It suffices to be disposed on the inner surface of at least one minute recess that exists on a surface that may come into contact (hereinafter, sometimes referred to as “surface to be grounded”). However, from the viewpoint of sufficiently obtaining a desired effect, it is preferable that nanomaterials are arranged on the inner surfaces of more minute recesses existing on the surface to be grounded.

The number of minute recesses on the surface to be grounded of the rubber member according to an example of the present invention is not particularly limited and can be appropriately determined according to the purpose. However, the performance on ice of a tire or the like is effective while maintaining rubber physical properties. From the viewpoint of improving the efficiency, it is preferably 70 to 200 pieces / mm ² , and more preferably 130 to 150 pieces / mm ² .
The number of minute recesses is the number of the minute recesses observed in each of the 10 mm square regions selected from a photograph of the surface of the rubber member grounded by an electron microscope. It can count and can obtain | require as the average value.

In addition, the rubber member of the example of the present invention includes not only a plurality of minute recesses 2 on the surface, but also a plurality of minute cavities 4 in the inside thereof, as in the example tread portion 1 shown in FIG. Moreover, in addition to the nano material 3a being arranged on the inner surface of the minute recess 2, the nano material 3b is preferably arranged on the inner surface of the plurality of minute cavities 4. Since the rubber member according to the example of the present invention has such an aspect, even if the surface is worn away due to long-term use, and the micro concave portion 2 disappears accordingly, the micro hollow portion 4 existing in the inside is renewed at any time. The new minute recesses and the nano material disposed on the inner surface function as drainage grooves and substantially increase the surface roughness of the rubber member. Therefore, the rubber member of an example of the present invention having the above-described aspect can provide high performance on ice for a tire or the like over a long period of time.
In addition, in the rubber member of an example of this invention, you may have the aspect with which the micro recessed part and the micro cavity part were connected.

  Here, the size of the microcavity is not particularly limited, but the length of the longest straight line connecting two arbitrary points on the inner surface is preferably 1 μm to 10 mm.

As described above, in the rubber member of the example of the present invention in which the nano material is also arranged on the inner surface of the microcavity, the nanomaterial is other than the inner surface of the microrecess 2 and the inner surface of the microcavity 4. For example, in the non-cavity 5. However, from the viewpoint of efficiently improving the performance on ice such as a tire without the need for excessively adding the nanomaterial, the ratio of the nanomaterial existing in the non-cavity portion 5 is preferably smaller. Such a rubber member has, for example, a foaming agent and a major axis of less than 100 nm when non-fibrous with respect to the rubber component, or a minor axis length of less than 100 nm when fibrous. By using a rubber composition formed by blending a nanomaterial having a major axis length of less than 1000 nm and a nanomaterial-containing organic fiber containing a resin, it can be suitably produced. In the rubber member manufactured using the above rubber composition, the ratio of the nanomaterial existing in the non-cavity portion is almost zero.
In this regard, it is considered that it is necessary to discuss a suitable aspect of the rubber member by specifying the “ratio of the nanomaterial existing in the non-cavity out of the total amount of the nanomaterial included in the rubber member”. . However, it takes a very long time to obtain the total amount of nanomaterials contained in the rubber member, which is not practical. Based on the above, it is clear that it is technically impossible to directly specify “the ratio of the nanomaterial existing in the non-cavity portion of the total amount of the nanomaterial included in the rubber member”.

In addition, in the rubber member according to an example of the present invention, it is also preferable that a large amount of nanomaterial is arranged on the inner surface of the minute recess 2. A rubber member in which a large amount of nanomaterials are arranged on the inner surface of the minute recesses can greatly improve the performance on ice particularly in the initial use of a tire or the like. In addition, as a method of arranging many nanomaterials on the inner surface of the minute recesses (increasing the proportion of nanomaterials arranged on the inner surface of the minute recesses out of the total amount of nanomaterials the rubber member has), for example, Examples include nanomaterial application, spraying or impregnation. This application, spraying or impregnation can be carried out at any timing after the rubber composition is vulcanized to prepare a vulcanized rubber having fine recesses, and is disposed on the inner surface of the microrecesses. Since the amount of the nanomaterial can be easily controlled, the production of the rubber member of the present invention can be facilitated.
In this regard, it is necessary to discuss the preferred embodiment of the rubber member by specifying the “ratio of the nanomaterial disposed on the inner surface of the minute recesses out of the total amount of the nanomaterial that the rubber member has”. It is thought that there is. However, it takes a very long time to obtain the total amount of nanomaterials contained in the rubber member, which is not practical. Based on the above, it is clear that it is technically impossible to directly specify the “ratio of the nanomaterial disposed on the inner surface of the minute recesses out of the total amount of the nanomaterial included in the rubber member”. is there.

Moreover, it is also preferable that the amount of nanomaterials disposed on the inner surface of each minute recess 2 is larger in the rubber member as an example of the present invention. More specifically, the average coverage of the nanomaterial on the inner surface of the minute recesses existing on the surface of the rubber member needs to be 10% or more, preferably 30% or more, and preferably 75% or more. More preferably. When the average coverage is less than 10%, performance on ice such as tires cannot be effectively improved.
From the same viewpoint, the average coverage of the inner surface of the minute recesses present on the surface to be grounded of the rubber member is preferably 10% or more, more preferably 30% or more, and 75% or more. Is more preferable.
In addition, in this specification, “the average coverage of the nano material on the inner surface of the minute recess” means the ratio of the total area covered with the nano material out of the area of the minute recess in the developed view of the surface of the rubber member It shall mean the average value of. The “average nanomaterial coverage on the inner surface of the minute recesses” is calculated from, for example, a photograph of the surface of the rubber member taken with an electron microscope (preferably binarized). It is possible to arbitrarily select 10 and calculate and calculate the ratio of the total area covered with the nanomaterial out of the total area of each minute recess.

-Nanomaterials-
When the nanomaterial used in the present invention has a shape other than fibrous (non-fibrous), the major axis is less than 100 nm, or when it is fibrous, the minor axis length is less than 100 nm and is long. The axial length must be less than 1000 nm. When the nanomaterial has a shape other than the so-called fibrous shape, if the major axis is 100 nm or more, the surface roughness of the rubber is not sufficiently high even if it is arranged in a minute recess of the rubber member, and the on-ice performance of the tire Cannot be improved effectively. In addition, when the nanomaterial is so-called fibrous, if the minor axis length is 100 nm or more or the major axis length is 1000 nm or more, the surface roughness of the rubber is sufficiently high even if the nanomaterial is disposed in a minute recess of the rubber member. It does not increase, and the on-ice performance of the tire cannot be improved effectively. Here, from the viewpoint of effectively improving the performance on ice and the viewpoint of easy procurement, when the nanomaterial has a shape other than the so-called fibrous shape, the major axis of the nanomaterial is preferably 1 to 80 nm, 60 nm is more preferable, 1-20 nm is still more preferable, and 5-15 nm is especially preferable. Moreover, from the viewpoint of effective improvement of performance on ice and the viewpoint of easy procurement, when the nanomaterial is so-called fibrous, the short axis length of the nanomaterial is preferably 1 nm or more and less than 100 nm, and preferably 1 to 50 nm. The major axis length of the nanomaterial is preferably 1 nm or more and less than 1000 nm, and more preferably 300 to 800 nm.
In the rubber member of the example of the present invention, a substance having a major axis of 100 nm or more or a substance that does not satisfy “minor axis length of less than 100 nm and major axis length of less than 1000 nm” is disposed on the inner surface of the minute recess. It doesn't matter. However, from the viewpoint of effectively improving the performance on ice, the rubber member of the example of the present invention is a fine material that does not satisfy the substance whose major axis is 100 nm or more and “minor axis length is less than 100 nm and major axis length is less than 1000 nm”. It is preferable that none of the substances is disposed on the inner surface of the minute recess.

  The shape of the nanomaterial is not particularly limited as long as the major axis is less than 100 nm when it is non-fibrous, or the minor axis length is less than 100 nm and less than 1000 nm when it is fibrous. The shape can be appropriately selected according to the purpose. Examples of the shape other than the fibrous shape include a particle shape, a layer shape, and a tetrapot shape. Here, it is important to select an appropriate nanomaterial in accordance with the size of the minute recess in consideration of the amount and size thereof.

The nanomaterial used in the present invention may be an organic material or an inorganic material.
When an inorganic substance is used as the nano substance, the material is not particularly limited and can be appropriately selected according to the purpose. For example, diamond, silica, glass, gypsum, calcite, fluorite, orthofeldspar, water Examples thereof include aluminum oxide, alumina, silver, iron, titanium dioxide, cerium oxide, zinc oxide, carbon black, single-walled carbon nanotube, multi-walled carbon nanotube, and clay. These may be used individually by 1 type and may use 2 or more types together. Among these, from the viewpoint of effectively improving the performance on ice of a tire or the like, a general ice Mohs hardness of 3 or higher, that is, diamond, silica, glass, aluminum hydroxide, alumina, titanium dioxide Is preferred. By using a nanomaterial having a Mohs hardness equal to or higher than that of general ice, a scratching effect or the like can be further exerted, and thus the performance on ice of a tire or the like can be greatly improved.
Here, the surface of the inorganic substance such as diamond described above may be modified with an arbitrary functional group (for example, a hydroxyl group, a carboxyl group, an amino group, etc.).

  Moreover, when using an organic substance as a nano substance, the material is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include cellulose and aramid. These may be used individually by 1 type and may use 2 or more types together.

-Rubber component-
The rubber component is not particularly limited and may be appropriately selected depending on the purpose. For example, natural rubber (NR) alone or diene synthetic rubber alone may be used. A diene synthetic rubber may be used in combination. The diene synthetic rubber is not particularly limited and may be appropriately selected depending on the intended purpose. For example, butadiene rubber (BR), styrene-butadiene rubber (SBR), isoprene rubber (IR), chloroprene rubber ( CR), ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), butyl rubber (IIR) and the like. These may be used individually by 1 type and may use 2 or more types together.

(Manufacturing method of rubber member)
The rubber member of an example of this invention can be manufactured using the rubber composition containing a rubber component and another arbitrary component as above-mentioned. Further, in producing the rubber member of an example of the present invention, it is necessary to form at least a plurality of minute recesses on the surface of the rubber member and to arrange a nano substance on the inner surface of the minute recess. is there. The method for achieving these is not particularly limited and can be appropriately selected depending on the purpose. Here, the method for producing a rubber member according to the present invention includes at least a step of imparting a nano material to a minute recess formed on the surface of the vulcanized rubber. Hereinafter, the manufacturing method of one Embodiment of the rubber member including this process is demonstrated in detail.

  The rubber member of an example of the present invention is obtained, for example, by preparing a rubber composition by blending at least a foaming agent with a rubber component (rubber composition preparation step A) and vulcanizing the prepared rubber composition. It can be manufactured through a process of scraping off the outer surface of the vulcanized rubber (vulcanization A process) and a process of applying nanomaterials to the minute recesses on the surface of the vulcanized rubber (nanomaterial application process). it can.

-Rubber composition preparation A step-
The rubber composition preparation step A is a step in which a foaming agent and any other component are blended with a rubber component and kneaded to obtain a rubber composition. Specific examples of the rubber component are the same as those already described. By blending the foaming agent, a plurality of minute recesses can be easily formed on the surface of the rubber member, and a plurality of minute cavities can be formed inside the rubber member.

  Examples of the foaming agent include dinitrosopentamethylenetetramine (DPT), azodicarbonamide (ADCA), dinitrosopentastyrenetetramine, benzenesulfonyl hydrazide derivative, p, p'-oxybisbenzenesulfonylhydrazide (OBSH), ammonium bicarbonate. , Sodium bicarbonate, ammonium carbonate, nitrososulfonylazo compound, N, N′-dimethyl-N, N′-dinitrosophthalamide, toluenesulfonyl hydrazide, p-toluenesulfonyl semicarbazide, p, p′-oxybisbenzenesulfonyl semicarbazide Etc. Among these, azodicarbonamide (ADCA) and dinitrosopentamethylenetetramine (DPT) are preferable from the viewpoint of processability. These foaming agents may be used individually by 1 type, and may use 2 or more types together. The blending amount of the foaming agent is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

  In the rubber composition preparation step A, it is preferable to use a foaming aid together with the foaming agent. Examples of the foaming aid include urea, zinc stearate, zinc benzenesulfinate, zinc white and the like. These may be used individually by 1 type and may use 2 or more types together. By using the foaming aid together with the foaming agent, the foaming reaction can be promoted to increase the degree of completion of the reaction, and unnecessary deterioration can be suppressed over time.

Further, in the rubber composition preparation step A, any other component such as a vulcanizing agent such as sulfur, a vulcanizing aid such as stearic acid, dibenzothiazyl disulfide or N-cyclohexyl-2 is added to the rubber component described above. -Vulcanization accelerators such as benzothiazolylsulfenamide, vulcanization accelerators such as zinc white, anti-aging agents, colorants, antistatic agents, dispersants, lubricants, antioxidants, softeners, carbon black, A filler such as silica can be blended. These may be used individually by 1 type and may use 2 or more types together.
And a rubber composition can be prepared by knead | mixing the component mentioned above in accordance with a conventional method.

-Vulcanization A process-
In the vulcanization A step, the rubber composition prepared in the rubber composition preparation A step is vulcanized to obtain a vulcanized rubber, and the outer surface of the vulcanized rubber is scraped off. In this vulcanization A step, the blended foaming agent foams to generate gas, and due to this gas, a plurality of microcavities and a plurality of microrecesses are formed in the vulcanized rubber. Further, by scraping off the outer surface of the vulcanized rubber, it is possible to more effectively obtain a surface on which a plurality of minute recesses derived from the above-described minute cavity are formed. The method for scraping off the outer surface of the vulcanized rubber is not particularly limited.
The vulcanization method is not particularly limited, and can be appropriately selected according to the type of rubber component. However, when the obtained rubber member is used for a tread portion of a tire, it is preferable to perform mold vulcanization. The vulcanization temperature is not particularly limited and may be appropriately selected depending on the vulcanization time or the like, but is preferably 100 to 200 ° C. from the viewpoint of obtaining desired rubber properties and a foaming rate. The vulcanization time is not particularly limited and may be appropriately selected depending on the vulcanization temperature and the like, but is preferably 3 to 25 minutes from the viewpoint of obtaining desired rubber properties and foaming rate.

3-40% is preferable and, as for the foaming rate (Vs) of the said vulcanized rubber, 5-35% is more preferable. When the foaming rate is 3% or more, the volume of the minute recesses and minute cavities from which water on the snowy and snowy road surface can be removed can be prevented from becoming too small, and the drainage performance can be prevented from being lowered. When the ratio is 40% or less, it is possible to prevent the durability of the tire from being lowered due to an excessive increase in the number of minute recesses and minute cavities.
The foaming rate (Vs) (%) is expressed by the following formula (I):
Vs = (ρ _o / ρ ₁ −1) × 100 (I)
[Wherein ρ ₁ is the density (g / cm ³ ) of the vulcanized rubber, and ρ ₀ is the density (g / cm ³ ) of the solid phase part in the vulcanized rubber].

-Nanomaterial application process-
The nanomaterial application step is a step in which the nanomaterial is applied (later) to the minute recesses formed on the surface of the vulcanized rubber obtained in the vulcanization A step to obtain the rubber member of the present invention. Specific examples of nanomaterials are the same as those already described.
The method for applying the nanomaterial is not particularly limited, and can be appropriately selected according to the type of the nanomaterial to be used. Examples of the method include a method of manually applying nanomaterials (application method), a method of spraying nanomaterials with gas using an instrument such as an airbrush (spraying method), and dispersing nanomaterials in a dispersion medium. And a method of impregnating the vulcanized rubber with the liquid obtained and then drying (impregnation method). In any of these methods, the nanomaterial can be easily arranged on the inner surface of the minute recess, compared with the case where the nanomaterial is arranged by blending, and the nanomaterial can be easily arranged on the inner surface of the minute recess. This is preferable in that the amount (average nanomaterial coverage on the inner surface of the minute recesses) can be controlled.

Examples of instruments that can be used in the spraying method include an airbrush “Meteo” manufactured by AIRTEX, an airbrush “74541” manufactured by Tamiya, and the like. Examples of gases that can be used in the spraying method include air, nitrogen, oxygen, propane, and the like. Among these, propane is preferable from the viewpoint of obtaining good adhesion.
The dispersion medium that can be used in the impregnation method is not particularly limited as long as it can be removed by drying. Examples thereof include water, methanol, ethanol, and isopropanol. Among these, a high drying rate and safety are mentioned. From the viewpoint of ensuring the above, ethanol and isopropanol are preferable. Further, in the impregnation method, the concentration of the nano substance in the liquid is not particularly limited and can be appropriately selected according to a desired average coverage, for example, 0.01 to 1.0% by mass. Preferably there is. Furthermore, the drying temperature in the impregnation method is not particularly limited and can be appropriately selected according to the boiling point of the dispersion medium to be used, but is preferably 10 to 200 ° C, for example. Furthermore, the drying time in the impregnation method is not particularly limited, and can be appropriately selected according to the concentration of the nanomaterial in the liquid. For example, it is preferably 10 to 360 minutes.

  In any of the coating method, the spraying method, and the impregnation method, nanomaterials can be disposed on the surface of the resulting rubber member other than the minute recesses, but this nanomaterial may or may not be removed. Good.

  The rubber member of the present invention includes, for example, a step of preparing a nanomaterial-containing organic fiber (fiber preparation step), and a rubber component containing at least a foaming agent and the nanomaterial, in addition to the manufacturing method of the above-described embodiment. A step of preparing a rubber composition by blending organic fibers (rubber composition preparation B step), a step of vulcanizing the prepared rubber composition and scraping off the outer surface of the obtained vulcanized rubber (vulcanization B) Can be manufactured by a method (hereinafter, referred to as “manufacturing method of another embodiment”).

-Fiber preparation process-
The fiber preparation step is a step of preparing a nanomaterial-containing organic fiber, and this nanomaterial-containing organic fiber is blended in order to dispose the nanomaterial on the inner surfaces of the minute recesses and minute cavities of the rubber member. is there. Here, the nanomaterial-containing organic fiber usually contains a resin and a nanomaterial. Note that specific examples of the nanomaterial, that is, a material having a major axis of less than 100 nm or a minor axis length of less than 100 nm and a major axis length of less than 1000 nm are the same as those already described.

  The resin preferably has a melting point or softening point lower than the maximum temperature reached by the rubber composition at the time of vulcanization of the rubber composition, that is, the maximum temperature of vulcanization. When nanomaterial-containing organic fibers are blended in a rubber composition containing a foaming agent, the resin constituting the nanomaterial-containing organic fibers melts or softens during vulcanization, while vulcanized in a rubber matrix. The gas generated from the foaming agent tends to stay inside the molten or softened resin constituting the fiber, compared to the rubber matrix in which the vulcanization reaction has progressed. Here, if the melting point or softening point of the resin is lower than the maximum vulcanization temperature, the resin rapidly melts or softens during vulcanization of the rubber composition, and the microcavity can be efficiently formed.

  Specific examples of such resins include crystalline polymer resins such as polyethylene (PE), polypropylene (PP), polybutylene, polybutylene succinate, polyethylene succinate, syndiotactic-1,2-polybutadiene (SPB). ), Polyvinyl alcohol (PVA), polyvinyl chloride (PVC), and the like, and those whose melting points are controlled within an appropriate range by copolymerization, blending, and the like. These crystalline polymer resins may be used alone or in combination of two or more. Among these crystalline polymers, polyethylene (PE) and polypropylene (PP) are preferable from the viewpoint of versatility and availability, and polyethylene (PE) is more preferable from the viewpoint of relatively low melting point and easy handling.

  The melting point or softening point of the resin is preferably lower by 10 ° C. or more and more preferably lower by 20 ° C. or higher than the maximum vulcanization temperature of the rubber composition. The industrial vulcanization temperature of the rubber composition is generally about 190 ° C. at the maximum. For example, when the maximum vulcanization temperature is set to 190 ° C., the melting point or softening point of the resin. Is usually selected within a range of 190 ° C. or lower, preferably 180 ° C. or lower, and more preferably 170 ° C. or lower.

  Here, it is preferable that the said nanomaterial containing organic fiber contains 0.5-200 mass parts of nanomaterials with respect to 100 mass parts of resin. When the content of the nanomaterial is 0.5 parts by mass or more, the obtained rubber member can greatly improve the performance on ice of a tire or the like, while when it is 200 parts by mass or less, high spinning is achieved. Operability can be maintained.

  The nanomaterial-containing organic fibers preferably have an average diameter of 10 to 100 μm. When the average diameter is 10 μm or more, the resin and the nanomaterial can be spun more reliably. When the average diameter is 100 μm or less, the number of blended parts of the nanomaterial-containing organic fibers in the rubber composition increases. It can be avoided.

  Furthermore, the nanomaterial-containing organic fibers preferably have an average length of 0.5 to 20 mm, and more preferably 1 to 10 mm. When the average length is 0.5 mm or more, minute recesses and minute cavities can be formed more easily, and when the average length is 20 mm or less, the hardness of the fiber does not become too high and is sufficiently mixed. can do.

  The method for preparing the nanomaterial-containing organic fiber is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include a melt spinning method, a gel spinning method, and a solution spinning method. For example, in the melt spinning method, the raw material resin is heated and melted in an extruder, and then the nanomaterial is dispersed, and then the bundle of fibers extruded from the spinning nozzle is stretched in a spinning cylinder and cooled by an air flow. The nanomaterial-containing organic fibers can be prepared by solidifying, then applying an oil agent, collecting them together, and winding them up. In the solution spinning method, nanomaterials are dispersed in a polymer solution in which a raw material resin is dissolved, and the nanomaterial-containing organic fibers are produced by extruding the nanomaterials from a spinning nozzle and desolvating the fibers. it can.

-Rubber composition preparation B step-
The rubber composition preparation B step is a step in which a rubber component is blended with a foaming agent, the nanomaterial-containing organic fiber prepared in the fiber preparation step, and any other component, and kneaded to obtain a rubber composition. is there. In addition, the specific content of the rubber composition preparation B process is the same as that of the rubber composition preparation A process mentioned above except the content shown below.

  The compounding amount of the nanomaterial-containing organic fiber in the rubber composition preparation B step is not particularly limited and can be appropriately determined according to the purpose, but is 0.5 to 30 mass with respect to 100 mass parts of the rubber component. Part. When the blending amount of the nanomaterial-containing organic fiber is 0.5 parts by mass or more, the volume ratio of the minute recesses and minute cavities in the vulcanized rubber is increased, and a sufficient amount of nanomaterial is added to the minute recesses and minute parts. By disposing in the cavity, the performance on ice of the tire can be effectively improved, and by being 30 parts by mass or less, the dispersibility of the nano-material-containing organic fibers in the rubber composition and the rubber composition The deterioration of workability can be suppressed.

-Vulcanization process B-
The vulcanization B step is a step in which the rubber composition prepared in the rubber composition preparation B step is vulcanized to obtain a vulcanized rubber, and the outer surface of the vulcanized rubber is scraped off to obtain the rubber member of the present invention. is there. In this vulcanization B step, the resin constituting the nanomaterial-containing organic fiber is melted by vulcanization, and the blended foaming agent is foamed to generate gas. Then, a film is formed so that the melted resin and nanomaterial surround the gas, and a plurality of microcavities and a plurality of microrecesses are formed on the surface of the vulcanized rubber. In addition to this, the total amount of the nanomaterials constituting the nanomaterial-containing organic fiber is caused on the inner surface of the coating, specifically, the surface constituted by the molten resin by the action of gas inflow from the foaming agent. It has been found that it moves up and is thus placed (attached) on the inner surface of the microcavity. Then, by scraping off the outer surface of the vulcanized rubber, it is possible to more effectively obtain a surface on which a plurality of minute recesses derived from the above-described minute cavity are formed. The method for scraping off the outer surface of the vulcanized rubber is not particularly limited.
Here, the specific content of the vulcanization B step is the same as the vulcanization A step described above.

  In addition, when manufacturing the rubber member of this invention, of course, you may combine the manufacturing method of one Embodiment mentioned above, and the manufacturing method of other embodiment. For example, the rubber member of the present invention can also be manufactured through a fiber preparation step, a rubber composition preparation B step, a vulcanization B step, and a nanomaterial application step.

(tire)
The tire of the present invention includes the above-described rubber member in a tread portion. According to such a tire, since the above-described rubber member is used at least in the tread portion, the performance on ice is improved. Therefore, the tire of the present invention is preferably used as a studless tire, particularly as a studless tire for passenger cars. The tire of the present invention is not particularly limited except that the above rubber member is used for the tread portion, and can be manufactured according to a conventional method.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to the following Example at all, In the range which does not change the summary, it can change suitably.

(Examples 1-7, Comparative Examples 1-12)
A rubber composition was prepared according to a conventional method with the formulation shown in Table 1. Using this rubber composition, a tread portion (unvulcanized) of a tire was prepared and disposed at an appropriate position to prepare a raw tire. This green tire was mold vulcanized at 165 ° C. for 20 minutes to obtain a vulcanized tire.
In addition, in Table 4 mentioned later, the mixing | blending prescription selected in each example is shown.

* 1 JSR Corporation, "BR01", cis-1,4-polybutadiene * 2 Asahi Carbon Corporation, "Carbon N220", agglomerate is 100 nm or more * 3 Nippon Silica Kogyo Co., Ltd., "Nipsil-VN3""Agglomerate is 100 nm or more * 4" Nocrack 6C "manufactured by Ouchi Shinsei Chemical Co., Ltd.
* 5 Dibenzothiazyl disulfide * 6 N-cyclohexyl-2-benzothiazolylsulfenamide * 7 Dinitrosopentamethylenetetramine * 8 Urea

Next, the passenger car equipped with the above vulcanized tire was run for 50 km or more to adjust the surface, and the outer surface of the tire was evenly scraped off by a predetermined thickness. In examples other than Comparative Examples 1, 2, and 10, the inorganic material shown in Table 2 below was prepared, and this inorganic material was vulcanized by the method shown in Table 3 below. The tread portion was applied to the inner surface of substantially all the microrecesses on the surface to be grounded. Thus, a radial tire for passenger cars of size 185 / 70R13 having a rubber member in the tread portion was manufactured.
In addition, in Table 4 mentioned later, the inorganic substance selected in each example and its provision method are shown.

* 10 “udiamond malt” manufactured by Air Brown Co., Ltd.
* 11 Made by Deggsa, wet silica, VN3 grade * 12 Made by Deggsa, wet silica, VN2 grade * 13 Made by Potters Barotini, "EMB10"

About the obtained tire, the foaming rate (Vs) (%) of the vulcanized rubber which forms a tread part was computed by the following formula (I). The results are shown in Table 4.
Vs = (ρ ₀ / ρ ₁ −1) × 100 (I)
[Wherein, ρ ₁ is the density (g / cm ³ ) of the vulcanized rubber, and ρ ₀ is the density of the solid phase part (g / cm ³ ) in the vulcanized rubber. ]

  Moreover, about the obtained tire, the surface form and internal form of the tread part as a rubber member, and the performance on ice of a tire were evaluated by the following method.

<Surface form and internal form of tread part>
A rubber piece including the surface to be grounded was cut out from the tread center portion of the obtained tire, and the surface and cut surface of this sample were observed with a scanning electron microscope (SEM). And the presence or absence of the micro recessed part in the surface to be grounded of a tread part, and the presence or absence of the micro cavity part in the inside of a tread part were confirmed.
Furthermore, from the photograph of the surface to be grounded of the tread portion taken with the SEM, arbitrarily select 10 micro-recesses, and out of the total area of each micro-recess, the ratio of the total area covered with the inorganic substance The average coverage (%) of the nano material on the inner surface of the minute recess was calculated. These results are shown in Table 4.

  Here, for reference, a schematic diagram of an image observed by the SEM on the surface of the sample in Comparative Example 2 is shown in FIG. 3, and a schematic diagram of an image by the SEM on the surface of the sample in Example 1 is shown in FIG. FIG. 5 shows a schematic diagram of an image observed by SEM on the surface of the sample in Example 6. From these figures, the average coverage of the nanomaterial on the inner surface of the minute recesses can be obtained by performing the binarization process.

<Tire performance on ice>
After the passenger car equipped with the obtained tire travels on an asphalt road for 200 km, travels on a flat surface on ice, brakes at a speed of 20 km / h to lock the tire, and the braking distance until the vehicle is stopped Was measured. The reciprocal of the braking distance of the tire of Comparative Example 1 is shown as an index with 100 as the inverse. The larger the index value, the better the performance on ice. The results are shown in Table 4.

(Examples 8 to 16, Comparative Examples 13 to 17)
First, the resin shown in Table 5 and the inorganic substance shown in Table 2 were prepared.

* 14 “HY 442” manufactured by Nippon Polyethylene Corporation.
* 15 "Kuraron K-11" manufactured by Kuraray Co., Ltd.
* 16 A value obtained by measuring durometer D hardness according to JIS K 7215.

Using the resin and inorganic substance prepared as described above, fibers were prepared according to a normal melt spinning method with the formulation shown in Table 6. Moreover, when 20 places were selected at random for each of the prepared fibers, the diameter and length were measured using an optical microscope, and the average values thereof were determined. All of the fibers had an average diameter of 30 μm and an average length. Was 2 mm.
In addition, the fiber selected in each example is shown in Table 8 mentioned later.

  Using the fibers prepared as described above, kneading was carried out according to a conventional method with the formulation shown in Table 7, and a rubber composition in which the blended fibers were arranged in a certain direction was prepared. Next, using this rubber composition, a tread portion (unvulcanized) of the tire was produced and disposed in an appropriate place to produce a raw tire. This green tire was mold vulcanized at 165 ° C. for 10 minutes to obtain a vulcanized tire. The maximum vulcanization temperature during vulcanization of each rubber composition was 165 ° C.

  * 17 Selected from the fibers listed in Table 6

  Next, the passenger car equipped with the above vulcanized tire was allowed to travel 50 km to adjust the surface, and the outer surface of the tire was uniformly scraped off by a predetermined thickness. Thus, a radial tire for passenger cars of size 185 / 70R13 having a rubber member in the tread portion was manufactured.

For the obtained tire, the foaming rate (Vs) (%) of the vulcanized rubber forming the tread portion is calculated by the same method as described above, and the presence or absence of minute recesses on the surface to be grounded of the tread portion, the inside of the tread portion The presence / absence of a microcavity and the average coverage (%) of the nanomaterial on the inner surface of the microrecess were determined, and the performance of the tire on ice was evaluated.
These results are shown in Table 8.

From Examples 1 to 16 in Table 4 and Table 8, there are a plurality of minute recesses, a nano material of a predetermined size is disposed on the inner surface of the minute recess, and the average coating of the nano material on the inner surface of the minute recess It can be seen that the rubber member of the example having a rate of 10% or more can improve the on-ice performance of the tire when used in, for example, a tread portion of a tire as a rubber article. On the other hand, Comparative Examples 4 to 7 in which there are no micro-recesses, Comparative Examples 2 to 10 to 14 in which nano-materials are not disposed in the micro-recesses or the average coverage is less than 10%, It can be seen that in Comparative Examples 3, 7 to 9, and 15 to 17 whose size is larger than the predetermined size, the performance on ice of the rubber article cannot be sufficiently improved as compared with the corresponding Examples. In Comparative Example 10, a method in which the nanomaterial was blended as it was at the time of preparing the rubber composition was adopted, but it was confirmed that this method could not properly arrange the nanomaterial on the inner surface of the minute recess. .
And from the comparison of Examples 8-10 of Table 8, the comparison of Examples 11-13, and the comparison of Examples 14-16, the on-ice performance of a tire is more effective by adjusting the size of a nano material. It can be seen that it can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, when used for rubber articles, such as a tire, the rubber member which can improve the performance on ice of a rubber article can be provided. Moreover, according to this invention, the manufacturing method of a rubber member which can obtain the rubber member which can improve the performance on ice of rubber articles, such as a tire, can be provided. Furthermore, according to the present invention, a tire with improved performance on ice can be provided.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Micro recessed part 3 Nano substance 3a Nano substance arrange | positioned on the inner surface of a micro recessed part 3b Nano substance arrange | positioned on the inner surface of a micro cavity part 4 Micro cavity part 5 Non-cavity part

Claims (5)

A rubber member having a nanomaterial having a major axis of less than 100 nm when non-fibrous, or a minor axis of less than 100 nm and a major axis of less than 1000 nm when fibrous.
There are a plurality of minute recesses on the surface of the rubber member,
The nanomaterial is disposed on the inner surface of the microrecess, and
The rubber member, wherein an average coverage of the nanomaterial on the inner surface of the minute recess is 10% or more. The rubber member according to claim 1, further comprising a plurality of microcavities therein, wherein the nanomaterial is also disposed on an inner surface of the microcavity,
For a rubber component, a foaming agent and a nanofiber having a major axis of less than 100 nm when non-fibrous, or a minor axis of less than 100 nm and a major axis of less than 1000 nm when fibrous. A rubber member produced using a rubber composition comprising a substance and a nano-material-containing organic fiber containing a resin.   The rubber member according to claim 1, wherein the nanomaterial is disposed on an inner surface of the minute recess by coating, spraying, or impregnation. A method for producing a rubber member according to any one of claims 1 to 3,
In the minute recesses formed on the surface of the vulcanized rubber, the major axis is less than 100 nm when it is non-fibrous, or the minor axis length is less than 100 nm when it is fibrous, and the major axis length is A method for producing a rubber member, comprising a step of applying a nanomaterial having a thickness of less than 1000 nm. A tire comprising the rubber member according to claim 1 in a tread portion.