JP2008056748A - Rubber material composition, rubber molded product and weather strip for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber molded product which sufficiently exerts desired functions and retains lubricity, non-sticking property, etc., without deteriorating its productivity and resistance to permanent set in fatigue. <P>SOLUTION: The rubber material composition is obtained by compounding at least an ethylene-α-olefin-nonconjugated polyene copolymer, carbon black, a softener and a silicone compound and is used to form at least the surface side of an abutment site of a rubber molded product. The molded product has a polymer material such as the rubber material compounded therein and is obtained by extrusion molding and vulcanization. A small amount of relatively large-grained carbon black (arithmetic average grain size of ≥60 nm, 50-100 phr) is used as the carbon black, and a silicone compound with viscosity (25°C) of ≥1,000 cSt is used as the silicone compound. On the rubber molded product comprising the rubber material composition, a carbon-derived uneven surface 10c is formed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rubber material composition, a rubber molded body, and a weather strip for automobiles, and is applied to, for example, automobile door panels and glass.

  Vulcanized moldings (hereinafter referred to as rubber moldings) composed of a rubber material composition in which a polymer material such as a rubber material is blended are applied to various uses and satisfy the characteristics according to the use. It has been researched and developed to be able to. For example, the rubber molded body is applied to another member (for example, in the case of a weather strip for an automobile, for example, a door portion or a trunk portion). In the case of a weather strip used for the door portion, it corresponds to a panel or glass, and in the case of a weather strip used for a trunk portion, it corresponds to a panel; hereinafter referred to as a contact target) (contact pressure, sliding contact, etc.) There are parts (for example, seal lips, etc .; hereinafter referred to as contact parts). In this contact portion, slipperiness (for example, a characteristic that prevents a low-pitched sound from being generated by stick-slip when a rubber molded body is slid with respect to the contact target) and anti-sticking property (for example, In the case where the property of preventing the rubber molded body from being deteriorated due to sticking between the rubber molded body and the contact target is low), for example, a surface treatment agent made of a polymer elastic material is used for the rubber molded body. A means for applying to the surface (at least the surface of a portion (contact portion or the like) that requires various characteristics) is employed.

  For example, in the case of a weather strip that is used for automobile doors (door panels) and that forms a sealing part (for example, a sealing part made of sponge rubber), a surface treatment agent is applied to the sealing part so that the door can be opened and closed. Is prevented from sticking between the seal portion and the door panel so that the opening and closing of the door does not become difficult. In addition, when the surface of the rubber molded body is used for sliding with glass, door panels, etc., the surface treatment agent increases the lubricity of the rubber molded body surface to prevent the generation of low-pitched sound due to stick slip. is doing.

  As the surface treatment agent, for example, a material obtained by adding diorganopolysiloxane to curable polyurethane is known, and the surface treatment agent is applied to a polymer molded body to provide lubricity, anti-sticking property and the like. It is known to improve. In addition, the layer of the applied surface treatment agent (hereinafter referred to as the surface treatment layer) may become thinner with time due to friction with the contact target (for example, local friction). For this reason, a method of ensuring a sufficient thickness of the surface treatment layer is employed.

  However, when the surface treatment agent is applied to the rubber molded body as described above, the application conditions (for example, the temperature and viscosity of the surface treatment agent at the time of application, the temperature of the rubber molded body to be coated) Etc.) depending on the thickness (for example, the surface treatment agent is not uniformly applied and the application spots are generated), or the thickness of the layer (hereinafter referred to as the surface treatment layer) by the applied surface treatment agent It was easy to become insufficient. Moreover, when the surface treatment layer is thick, if the surface treatment layer has insufficient elasticity (elongation permanent distortion, etc.), functions such as elasticity of the rubber molded body itself may be deteriorated.

  For this reason, depending on the application of the surface treatment agent (for example, depending on the thickness of the surface treatment layer), the productivity (product yield, etc.) of the target rubber molded product may be reduced, and sufficient lubricity, There is a possibility that the function of the rubber molded body (for example, sealability in the case of a weather strip) or the like cannot be exhibited without sticking properties and the like.

In recent years, instead of using a surface treatment agent as described above, a silicone compound is blended with an ethylene-α-olefin / non-conjugated polyene copolymer, and rubber moldings (particularly brake cups) are produced by bleeding the silicone compound. Techniques for imparting lubricity and the like are known. As the silicone compound, one having a viscosity (25 ° C.) of 1000 Pa · s or more (corresponding to about 1 × 10 ⁶ cSt or more) is used (for example, Patent Document 1).

However, as described above, the technology of simply blending a silicone compound with the rubber molded body itself to impart lubricity is not assumed with respect to sticking resistance and the like, and may maintain the lubricity for a long period of time. It was not supposed.
Japanese Patent No. 3511899.

  As described above, the rubber molded body can be provided with slipperiness, sticking resistance, etc. without using a surface treatment agent, and the slipperiness, sticking resistance, etc. can be maintained for a long period of time. A technique capable of fully exerting the functions of has been desired.

  The present invention has been made on the basis of the above problems, and aims to improve the lubricity, sticking resistance, and the like of a rubber molded body without impairing productivity without performing application of a surface treatment agent or the like. An object of the present invention is to provide a rubber material composition, a rubber molded body, and a weather strip for automobiles that sufficiently exhibit the functions of the rubber molded body and that have physical properties such as slidability and adhesion resistance for a long period of time.

  Specifically, the invention according to claim 1 is used on at least the surface side of the contact portion of the rubber molded body by extrusion molding vulcanization, and includes at least 100 phr of an ethylene-α-olefin / non-conjugated polyene copolymer. A rubber material composition containing carbon black 50 phr to 100 phr having an arithmetic average particle size of 60 nm or more, a softening agent 100 phr or less, and a silicone compound having a viscosity (25 ° C.) of 1000 cSt or more.

  The invention described in claim 2 is characterized in that, in the invention described in claim 1, a foaming agent is blended.

  The invention according to claim 3 is a rubber molded body obtained by extruding and vulcanizing the rubber material composition according to claim 1 or 2, wherein at least the surface side of the contact portion of the rubber molded body is derived from carbon. An uneven surface (that is, an uneven surface resulting from the particle size, blending amount, etc. of carbon black) is formed, and the specific gravity is 0.3 or more.

  The invention according to claim 4 is characterized in that, in the invention according to claim 3, the static friction duration index Δμs and the dynamic friction duration index Δμd are 0.9 or less and 0.7 or less, respectively, and the sticking resistance duration index ΔS is 80 or less. And

  The invention according to claim 5 is an automotive weather strip formed by extrusion molding and vulcanizing the rubber material composition according to claim 1 or 2, wherein at least the surface of the contact portion of the weather strip has unevenness derived from carbon. A surface is formed, and the specific gravity is 0.3 or more.

  The invention according to claim 6 is the invention according to claim 5, wherein the static friction duration index Δμs and the dynamic friction duration index Δμd are 0.9 or less and 0.7 or less, respectively, and the anti-sticking duration index ΔS is 80 or less. It is characterized by.

  As described above, at least 100 phr of ethylene-α-olefin / non-conjugated polyene copolymer, 50 phr to 100 phr of carbon black having an arithmetic average particle size of 60 nm or more, 100 phr or less of a softening agent, and a viscosity (25 ° C.) of 1000 cSt or more. Since the surface treatment agent or the like is not applied by the rubber material composition containing the silicone compound, it is not necessary to consider the application conditions.

  In addition, a rubber molded body obtained by extrusion molding and vulcanizing the rubber material composition is blended with 50 phr to 100 phr of carbon black having an arithmetic average particle size of 60 nm or more, so that ethylene-α is locally contained in the rubber molded body. -Since a part with a large amount of olefin / non-conjugated polyene copolymer component is formed and shrinkage occurs at that part, a carbon-derived uneven surface with surface roughness due to the particle size, blending amount, etc. of the carbon black is formed. The Thereby, the contact area of the said rubber molded object and contact object becomes small.

  The blending amount of the above-mentioned ethylene-α-olefin / non-conjugated polyene copolymer, carbon black, softening agent, and silicone compound does not impair the properties of the intended rubber material composition and rubber molding. It is preferable to set the degree.

  For example, if the blending amount of the above-mentioned ethylene-α-olefin / non-conjugated polyene copolymer, carbon black, softener, and silicone compound is outside the range shown in the present invention, the kneadability and extrudability of the rubber material composition In addition, the properties (sliding property, sticking resistance, etc.) of the rubber molded body may be deteriorated.

  When the amount of carbon black is too small, the kneading processability and extrusion moldability of the rubber material composition are impaired, and when it is excessive, the carbon-derived uneven surface of the rubber molded body may not be formed.

  When the silicone compound is excessively blended, the rubber molded body may be melt-bonded (for example, melt-bonding with a thermoplastic elastomer or melt-bonding when a rubber member is injection-molded). It can be difficult. If the viscosity of the silicone compound is too low, kneading processability and the like may be impaired. If the viscosity of the silicone compound is too low (for example, about 100 cSt), the kneading processability of the rubber material composition may be impaired.

  In the softening agent, when the softening agent has adhesiveness, there is a possibility that the sticking resistance of the rubber molded body is impaired when it is excessively blended.

  When the foaming agent is blended, if the blending amount is excessive, the specific gravity of the rubber molded body becomes too small (for example, compared with the specific gravity of a rubber molded body such as a general automobile weather strip). When the specific gravity of the rubber molded body is too small as described above, the foamed cells inside the rubber molded body increase, which may inhibit the bleed of the silicone compound and the bleed speed may be too slow.

  The static friction persistence index Δμs and the dynamic friction persistence index Δμd are determined by comparing the static friction coefficient and the dynamic friction coefficient before and after thermal acceleration deterioration treatment of the rubber molded body (for example, calculated based on the formula (3) described later). Is. Further, the sticking resistance index ΔS is determined by comparing the sticking resistance before and after the thermal accelerated deterioration treatment of the rubber molded body (for example, calculation based on the formula (2) described later).

  In addition to the above-mentioned materials, for example, various materials used in the technical field of rubber moldings by general extrusion molding vulcanization may be appropriately blended. It is preferable that the properties of the article and the rubber molded body are not impaired.

  For example, when using vulcanizing agents, vulcanization accelerators, vulcanization accelerating aids, etc., if the blending amount is too small, the vulcanization progresses slowly, and if the blending amount is too large, the Bloom phenomenon may occur. There is.

  According to the first and second aspects of the invention, the rubber material composition has good kneadability and extrudability, and the rubber material composition is extruded and vulcanized as in the third to sixth aspects of the invention. In the resulting rubber molded body, a carbon-derived rough surface is formed, the contact area between the surface of the rubber molded body and the contact object is reduced, and bleeds remain on the carbon-derived uneven surface, for example, application of a surface treatment agent Therefore, physical properties such as sufficient slipperiness and sticking resistance are maintained without impairing productivity and sag resistance (for example, sealability in the case of weather strips). . Thereby, the function of the target rubber molding can be fully exhibited.

  Further, according to the invention described in claim 2, the contact area becomes smaller, and physical properties such as sticking resistance become better.

  Furthermore, according to invention of Claim 3, 5, physical properties, such as favorable lubricity and sticking resistance, remain more stably.

  Furthermore, according to the fourth and sixth aspects of the invention, physical properties such as lubricity and sticking resistance equal to or higher than those obtained when at least a surface treatment layer is provided can be obtained.

  Hereinafter, a rubber material composition, a rubber molded body, and an automobile weather strip in an embodiment of the present invention will be described in detail with reference to the drawings.

  The present embodiment relates to a rubber molded body obtained by blending a polymer material such as a rubber material (for example, ethylene-α-olefin / non-conjugated polyene copolymer) and extrusion molding vulcanization. At least the above-mentioned polymer material, carbon black, softening agent, and silicone compound are blended at least on the surface side of the contact part, and a small amount of the carbon black having a relatively large particle size (general extrusion molding) The amount of rubber molded body treated by vulcanization (for example, smaller than 140 phr or more) is used, and the silicone compound having a viscosity (25 ° C.) of 1000 cSt or more is used.

  In general extrusion molding vulcanization, after the rubber material composition is discharged from the die of the extrusion molding machine, the discharged product (extruded product) is in a free state (unlike mold molding, the pressure on the discharged product is almost The target rubber molding is obtained by carrying out a crosslinking reaction in a non-applying state. For example, carbon black with an average particle size of less than 60 nm is blended with an ethylene-α-olefin / non-conjugated polyene copolymer as a general rubber molded product (rubber molded product obtained by extrusion molding and vulcanizing a rubber material composition). When the blending amount is more than 100 phr even if it is 60 nm or more, as shown in the structural model diagram of FIG. 1A, the surface of the rubber molded body 10 (flat surface indicated by reference numeral 10a in the drawing) is compared. Flat.

  When a silicone compound is blended in the rubber molded body 10 as shown in FIG. 1A, the silicone compound bleeds on the flat surface 10a as shown in FIG. 1B, and is slid by the bleed material (reference numeral 10b in the figure). The bleed material 10b on the flat surface 10a is caused by, for example, wiping by the assembling work of the rubber molded body 10 or sliding with the contact target of the application target. It can be easily removed. In this case, the bleed of the silicone compound occurs again to obtain lubricity, sticking resistance, etc., but it takes a predetermined time to reach the bleed.

  On the other hand, as in this embodiment, rubber formed by extrusion molding and vulcanizing a rubber material composition in which carbon black having an average particle size of 60 nm or more is blended in an amount of 100 phr or less in the ethylene-α-olefin / non-conjugated polyene copolymer. In the case of a molded body, as shown in the structural model diagrams of FIGS. 1C and 1D (partially enlarged view of FIG. 1C), a carbon-derived uneven surface 10c having a small surface roughness with respect to the surface of the rubber molded body 10 is formed. Is done. This is because the blended amount of carbon black having a large particle size is relatively small, so that a portion having a large amount of ethylene-α-olefin / non-conjugated polyene copolymer component is locally formed in the rubber molded body 10. This is thought to be due to the possibility of causing shrinkage or the like at that portion.

  Further, in the present embodiment, as shown in FIG. 1E, the silicone compound bleeds on the carbon-derived uneven surface 10c, and the bleed material is wiped off by, for example, assembling work of a rubber molded body or applied to an object to be applied. When sliding with the contact target is performed, as shown in FIG. 1F, the bleed object 10b on the outer peripheral side of the carbon-derived uneven surface 10c (especially, the outer peripheral side of the convex portion of the carbon-derived uneven surface 10a) Although there is a possibility of being easily removed, the bleed material on the inner side (particularly, the concave portion of the carbon-derived uneven surface 10c) of the carbon-derived uneven surface 10c remains difficult to be removed.

  As shown in FIG. 1F, when there is a region 10d from which the bleed material 10b is removed (hereinafter referred to as a removal region) in the uneven surface 10c derived from carbon, the remaining bleed material (at least a part of the bleed material) is removed. Move to the area. Further, in the concave portion 10c derived from carbon, particularly in the concave portion, the amount of the bleed material 10b is further increased due to a change with time in the remaining bleed material 10b, and as a result, the bleed material 10b easily moves to the removal region 10d.

  Therefore, according to this embodiment, even if the bleed material 10b is removed on the carbon-derived uneven surface 10c as in the removal region 10d and the state shown in FIG. 1F is obtained, as shown in FIG. 1E (G). It is easy to return to the state, and the slipperiness and sticking resistance etc. are stably maintained for a long time.

  In the rubber material composition and rubber molded body of the present embodiment, not only the ethylene-α-olefin / non-conjugated polyene copolymer, carbon black, softener, and silicone compound as shown below, Various additives such as a foaming agent, a vulcanizing agent, a vulcanization accelerating aid, a vulcanization accelerating aid, a processing aid, and an inorganic filler may be appropriately blended.

[Ethylene-α-olefin / non-conjugated polyene copolymer]
In the ethylene-α-olefin / non-conjugated polyene copolymer, as the α-olefin, for example, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene Etc., preferably propylene. Of course, a plurality of these α-olefin groups may be selected and used in combination, for example, propylene and 1-butene.

  In addition, the polyene copolymer is a cyclic non-conjugated polyene such as 5-ethylidene-2-norbornene, dicyclopentadiene, 5-vinyl-2-norbornene, norbornadiene, methyltetrahydroindene, 1,4 hexadiene, 7 -Methyl-1,6-octadiene, 4-ethylidene-8-methyl-1,7-nonadiene, 4-ethylidene-1,7undecadiene, 4,8-dimethyl-1,4,8-decatriene, etc. Those that are non-conjugated polyenes. Each of these non-conjugated polyenes may be used alone or in combination of two or more, and the constitutional unit (content ratio of non-conjugated polyene in the ethylene-α-olefin / non-conjugated polyene copolymer) is, for example, 1 wt% to 20 wt%. And preferably 1 wt% to 15 wt%, more preferably 5 wt% to 11 wt%. As such an ethylene-α-olefin / non-conjugated polyene copolymer, for example, Keltan 7341A manufactured by DSM Elastomers can be applied.

[Carbon black]
The carbon black is applied, for example, in the technical field of rubber moldings, and has an average particle diameter (arithmetic average particle diameter) of 60 nm or more, preferably 60 nm to 90 nm. Moreover, since the kneading | mixing process will become difficult when the compounding quantity of this carbon black is less than 50 phr, it is 50 phr or more and 120 phr or less, Preferably it is 50 phr or more and 100 phr or less. As such carbon black, for example, Asahi Carbon Black / Asahi # 50 or Asahi Carbon Black / Asahi # 55 manufactured by Asahi Carbon Co., Ltd., a lot having an arithmetic average particle diameter of 60 nm or more can be selected and applied.

[Softener]
Examples of the softener include petroleum softeners such as process oil, paraffinic oil, lubricating oil, liquid paraffin, petroleum asphalt, and petroleum jelly, coal tar softeners such as coal tar and coal tar pitch, and castor oil. , Fatty oil softeners such as linseed oil, rapeseed oil and coconut oil. Of these softeners, petroleum softeners are preferable, and paraffin oil is more preferable. The softening agent as described above is used in a blending amount that does not impair the properties of the intended rubber material composition or rubber molded body, and is, for example, 100 phr or less.

[Silicone compound]
As said silicone compound, what has a viscosity of 1000 cSt (25 degreeC) or more can be used. Specific examples include silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, and silicone gel (so-called gummy silicone). More specifically, for example, KF96, KF50, KE76BS manufactured by Shin-Etsu Chemical Co., Ltd., TSF451, TSF456, TSF3051 manufactured by GE Toshiba Silicone, etc. may be mentioned. , Can be preferably used. Moreover, each said silicone compound may use any 1 type, and may use it combining several types of things. Furthermore, it is preferable to use the silicone compound as described above in such a blending amount that does not impair the properties of the intended rubber material composition or rubber molded body. More preferably, it is 1-30 phr, More preferably, it is 2-15 phr.

[Foaming agent]
As said foaming agent, an organic type foaming agent, a thermal expansion capsule, etc. can be applied suitably. Specific examples of the organic foaming agent include 4,4-oxybisbenzenesulfonyl hydrazide (OBSH), azodicarbonamide (ADCA), dinitrosopentamethylenetetramine (DPT), azobisisobutyronitrile (AIBN), para Examples include toluenesulfonyl hydrazide (TSH), hydrazodicarbonamide (HDCA), and barium azocarboxylate. This organic foaming agent is preferably used to such an extent that it does not impair the properties of the intended rubber material composition or rubber molding (for example, 0 to 10 phr). In addition to the above organic foaming agents, foaming aids such as urea derivatives, salicylic acid, phthalic acid, and stearic acid may be used.

  As a specific example of the thermally expanded capsule, for example, a liquid (for example, low boiling point hydrocarbon or chlorinated hydrocarbon) capable of generating a gas by heating is filled in a shell wall (for example, spherical shell wall) of a thermoplastic resin. (Thermally expandable thermoplastic resin particles) having a true specific gravity of 0.1 or less, a particle size (median diameter) of 5 μm to 100 μm, and the liquid is not less than the expansion start temperature (for example, 120 ° C. to 150 ° C.) Liquid-encapsulated thermoplastic resin particles that expand by heating at a temperature of (for example, heating at the vulcanization temperature) and form a thermal expansion cell (for example, a thermal expansion cell of 30 μm to 300 μm) in the target rubber molded body. It is done.

  When the expansion start temperature of the thermal expansion capsule is sufficiently lower than the vulcanization temperature of the target rubber molded body (for example, when the peak temperature of the vulcanization temperature is about 170 ° C., about 120 ° C. to 150 ° C.) Since a vulcanized rubber molded body is obtained after the structure by the thermal expansion cell is formed during the vulcanization process, even if there is a variation in vulcanization temperature that may occur in the production process, the rubber molding There is almost no variation in the specific gravity of the body. In other words, sponge rubber can be produced with a stable specific gravity.

  Moreover, as a component of the thermoplastic resin which comprises the shell wall of the said thermal expansion capsule, Preferably a (meth) acrylonitrile polymer and a polymer containing many (meth) acrylonitrile are mentioned, Examples of monomers (so-called counterpart monomers; comonomers) include monomers such as vinyl halides, vinylidene halides, styrene monomers, (meth) acrylate monomers, vinyl acetate, butadiene, vinyl pyridine, and chloroprene.

  The shell wall is preferably uncrosslinked, but may be crosslinked with a general crosslinking agent such as divinylbenzene or ethylene glycol di (meth) acrylate. Examples of the liquid filled in the thermally expanded capsule include hydrocarbons such as n-pentane, isopentane, neopentane, butane, isobutane, hexane, and petroleum ether, and chlorine such as methyl chloride, dichloroethylene, trichloroethane, and trichloroethylene. Hydrocarbons.

  As a further specific example of the thermal expansion capsule, H770D, H850D, and M430, which are the same series, as well as Die Form H750D manufactured by Dainichi Seika Kogyo Co., Ltd. can be suitably used. Further, for example, Matsumoto Microspheres F80S-D, F85D, F100D, F105-D, F82-D manufactured by Matsumoto Yushi Co., Ltd., EXPANCEL091DU-80, 092DU-120 manufactured by EXPANSEL, Sweden, etc. are applied. You can also The amount of the thermally expanded capsule is preferably, for example, 1.0 phr to 15 phr.

  When such a thermally expanded capsule is added to a polymer material such as an ethylene-α-olefin / non-conjugated polyene copolymer, in order to prevent scattering of the thermally expanded capsule and improve dispersibility, It may be used after being mixed with a material to be used (for example, polymer elastic body, thermoplastic resin, softener, inorganic filler or the like). When the thermally expanded capsule is used after previously mixed with other materials used, the mixing ratio of the foaming agent is adjusted to 10 wt% to 99 wt%, preferably 10 wt% to 50 wt%. Moreover, any one kind of the above-mentioned thermally expanded capsules may be used, or a plurality of kinds may be used in combination.

  As the blending amount of the foaming agent increases, the specific gravity of the rubber molded body decreases. However, if the specific gravity is too small, the bleed speed of the silicone compound tends to decrease, so the blending amount is It is preferable to adjust appropriately (for example, adjust so as to ensure a specific gravity of 0.3 or more).

[Vulcanizing agent]
Examples of the vulcanizing agent include sulfur, and it is used in a blending amount that does not impair the properties of the intended rubber material composition or rubber molded body, and preferably about 0.5 phr to 2 phr.

[Vulcanization accelerator]
Examples of the vulcanization accelerator include thiazole type, thiuram type, sulfenamide type, guanidine type, thiourea type, and dithiocarbamic acid type, which impair the characteristics of the intended rubber material composition and rubber molding. It is used in a blending amount that is not excessive, preferably about 2 phr to 8 phr.

[Vulcanization acceleration aid]
Examples of the vulcanization acceleration aid include zinc oxide (zinc white), zinc carbonate, magnesium oxide, calcium hydroxide, zinc monoxide and the like, preferably zinc oxide and magnesium oxide. These vulcanization accelerating aids are used in a blending amount that does not impair the properties of the intended rubber material composition or rubber molded body, and preferably about 5 phr.

[Processing aid]
Examples of the processing aid include higher fatty acids such as stearic acid, ricinoleic acid, palmitic acid and lauric acid, esters of the higher fatty acids, salts of higher fatty acids such as stearic acid, and other rubber moldings. A compound that is treated as a processing aid in the technical field may be used. These processing aids are used in an amount so as not to impair the properties of the intended rubber material composition and rubber molded body, preferably about 5 phr, more preferably 3 phr or less.

[Inorganic filler]
Examples of the inorganic filler include calcium carbonate, clay, silica, calcium silicate, magnesium carbonate, magnesium hydroxide, aluminum oxide, kaolin, mica, zeolite, and the like. These types may be used in combination. The inorganic filler as described above is used in a blending amount that does not impair the properties of the target rubber material composition or rubber molded body, and is, for example, about 0 to 100 phr.

[Other additives]
In addition to the above-mentioned various additives, dehydrating agents, antioxidants, anti-aging agents, heat stabilizers, light stabilizers, UV absorbers, neutralizers, lubricants, anti-clouding agents, anti-blocking agents, slip agents, Dispersant, flame retardant, antistatic agent, conductivity imparting agent, tackifier, crosslinking agent, crosslinking aid, metal deactivator, molecular weight regulator, antibacterial / antifungal agent, fluorescent whitening agent, sliding property Improving agent, colorant (such as titanium oxide), metal powder (such as ferrite), glass fiber, inorganic fiber (such as metal fiber), carbon fiber, organic fiber (such as aramid fiber), composite fiber, glass balloon, glass flake, graphite , Carbon nanotube, fullerene, barium sulfate, fluororesin, filler polyolefin wax (polymer beads, etc.), cellulose powder, rubber powder, recycled rubber, etc. Combined, it may be used as appropriate according to the rubber material composition and rubber molded article of interest.

[Production method]
When the desired rubber material composition is obtained by kneading the ethylene-α-olefin / non-conjugated polyene copolymer, carbon black, softener, silicone compound and various additives, for example, a tangential mixer, meshing Various closed kneaders such as a mixer and a kneader, a continuous twin-screw extrusion kneader, an open roll, and the like can be appropriately applied. When the rubber material composition is subjected to extrusion molding vulcanization (for example, extrusion molding vulcanization at 200 ± 40 ° C.) to obtain a target rubber molding, for example, a continuous hot air vulcanizer (HAV), A high frequency vulcanizer (UHF) and other general vulcanizers can be applied. Moreover, you may apply the said various apparatuses as needed (for example, combining a combination of continuous hot air vulcanization and high frequency vulcanization).

  Next, various rubber material compositions (rubber compounds S1 to S12 (Examples) and P1 to P14 (Comparative Examples) described later) are prepared based on the present embodiment, and the processability of these rubber material compositions and The physical properties and the like of rubber molded bodies (samples GS1 to GS12 (examples) and GP1 to GP14 (comparative examples) described later) were examined.

  First, 100 phr of ethylene-propylene-5-ethylidene-2-norbornene (DSM, Elastomers, Keltan 7341A) was used as a polymer material and masticated with a closed mixer. Thereafter, one type of carbon black having an arithmetic average particle size of 80 nm, 60 nm, and 45 nm (hereinafter referred to as carbon 80 nm, 60 nm, and 45 nm, respectively) is added to 45 phr to 140 phr and a softening agent (adhesive property). One kind of silicone compound (dimethyl silicone oil KF96 manufactured by Shin-Etsu Chemical Co., Ltd.) having a softening agent (process oil P-300 manufactured by JOMO) of 80 phr to 110 phr and a viscosity (25 ° C.) of 100 cSt, 1000 cSt, 100000 cSt. 0 to 5 phr was added and kneaded for a predetermined time.

  In the present embodiment, the above-mentioned carbon 80 nm, 60 nm, and 45 nm are obtained from the material lots of Asahi Carbon Black, Asahi # 50, Asahi # 55, and # 60 manufactured by Asahi Carbon Co., respectively. , 45 nm was selected and used. In addition to the above materials, 1 phr of stearic acid as processing aid, 1 phr of polyethylene glycol, 30 phr of calcium carbonate as inorganic filler, 3 phr of active zinc white as inorganic vulcanization accelerating aid, and oxidation as dehydrating agent After adding 5 phr of calcium, the mixture was kneaded with a 5 L hermetic kneader for 5 minutes.

  Thereafter, the kneaded product obtained with the above-mentioned closed kneader is taken out and kneaded with an open roll machine, and 0 to 15 phr of thermal expansion capsule (Daifoam H750D manufactured by Dainichi Seika Kogyo Co., Ltd.) as the foaming agent, organic foaming 0 to 7 phr of 4,4-oxybisbenzenesulfonyl hydrazide type as neocelbon N # 1000SW manufactured by Eiwa Kasei Kogyo Co., Ltd., and thiazole type, thiuram type and sulfenamide type as vulcanization accelerators 5 phr, 1 phr of sulfur as a vulcanizing agent (added after the kneaded material is wound on a roll), and mixing (blending) for a predetermined time, rubber compositions having various compositions as shown in Table 1 described later ( Ribbon-like unvulcanized rubber compounds) S1 to S12 and P1 to P14 were obtained.

  Next, in each of the rubber compounds S1 to S12 and P1 to P14, extrusion molding is performed using an extrusion molding machine for a rubber molded body (having a die shape such that a molded body shown in FIG. 2 described later is obtained). 2 by adjusting the screw rotation speed with an extrusion extruder, and then vulcanizing the extruded product with a continuous hot-air vulcanizer (at a temperature of 200 ° C. for 10 minutes). As shown in FIG. 2, a rubber molded body (having a height of 20 mm) provided with a tube portion (tube with a thickness of 2 mm) 22 having a substantially circular cross section with respect to a substantially flat base portion (a base portion with a thickness of 2 mm and a width of 25 mm) 21. Rubber molded bodies) samples GS1 to GS12 and GP1 to GP14 (reference numeral 20 in the figure) were prepared.

  A surface treatment agent comprising 85 phr of urethane polyol, 15 phr of polyisocyanate, 40 phr of diorganosiloxane, 40 phr of curable silicone oil, 4 phr of catalyst, 15 phr of matting agent, and 1500 phr of solvent is applied to the surfaces of the above samples GP2 to GP4. It shall be applied.

  Processability (kneading processability, extrusion moldability) of each rubber compound S1 to S12, P1 to P14 produced as described above, and specific gravity and sag resistance (extension permanent) of each sample GS1 to GS12, GP1 to GP14 Strain rate), resistance to sticking (sticking force, sticking resistance index), and slipperiness (friction coefficient, frictional index) are measured by the following methods, respectively, and the measurement results are shown in Table 2 below. It was. In addition, in the items of comprehensive evaluation in Table 2 to be described later, the symbols “◎”, “○”, “△”, and “×” are sufficiently applicable if they can be applied satisfactorily as rubber molded articles such as weather strips for automobiles. When possible, indicate the possibility of application, and the case where application is difficult.

[Kneading processability]
Each rubber compound was kneaded with an open roll machine having a 14-inch roll and a distance between the rolls set to 5 mm, and the wrapping property of the rubber compound with respect to each roll was observed. In addition, in the kneading processability item of Table 2 described later, the symbol “記号” indicates a case where the rubber compound easily enters between the rolls and is wound so as to be in close contact with the rolls, and the symbol “×” indicates the rubber. The case where the compound hangs down without being in close contact with each roll or is cut in the middle is shown. In addition, the symbol “◯” indicates that the rubber compound is less likely to enter between the rolls than the symbol “」 ”, but the rubber compound is wound so as to be in close contact with the roll over time.

[Extrudability]
Extrusion for 1 minute in each rubber compound (rubber compound adjusted to a temperature of 60 ± 5 ° C. at the time of extrusion) by an extruder with a diameter of 75 mm and a rotation speed set to 15 rpm. The rubber molded bodies (samples 20) having the shapes shown in FIG. 2 were obtained.

  This extrusion molding was repeated 100 times for each rubber compound, and the mass (g) of the extruded product (unvulcanized product) discharged from the extruder for each extrusion molding was weighed as a discharge amount. And the dispersion | variation (%) of discharge amount was computed by the following (1) formula for every rubber compound.

  Discharge amount variation (%) = ((“maximum discharge amount” − “minimum discharge amount”) / average discharge amount) × 100 (1).

[specific gravity]
Regarding the specific gravity, a sample piece having a thickness t of 2 mm and a size of 20 × 20 mm was prepared from the sample 20, and the surface was wiped with alcohol to remove dirt. Thereafter, the specific gravity was calculated from the mass difference between air and pure water using an automatic hydrometer (manufactured by Toyo Seiki Seisakusho) in an atmosphere at 25 ° C. The automatic hydrometer is based on JIS K6220.

[Sagging resistance (elongation set)]
In order to conduct a substitute evaluation test for sag resistance, a JIS standard dumbbell No. 3 type (thickness 2 mm) sample piece (sample 2) as shown in FIG. (It is assumed that two mark lines 30a and 30b are written at a central portion of the piece with an interval L ₀ (20 mm) therebetween).

Next, the sample piece 30 is stretched at a stretch rate of 50% (30 mm) (stretched in the directions of arrows A and B in FIG. 3), fixed to a jig, and heated for 48 hours in an atmosphere at a temperature of 80 ° C. After that, the stretched state was left at room temperature for 3 hours. Thereafter, the sample piece 30 was removed from the jig to release the extension, and the length L ₁ between each marked line at the extension rate was measured.

Then, the length change rate (%) of the molded body calculated by the following formula (2) was used as the elongation set rate, and the sag resistance of the sample piece 30 was evaluated. In the following formula (2), L ₀ indicates the length between the marked lines 30a and 30b of the sample piece 30 before being fixed to the jig (before extension), and L ₂ is the sample piece 30 at the time of extension. It shows the length between the respective marked lines 30a, 30b.

“Sag resistance (elongation set (%))” = ((L ₁ −L ₀ ) / (L ₂ −L ₀ )) × 100 (2).

[Attachment resistance]
As shown in FIGS. 4A (plan view), B (side view), and C (operation diagram), the sample 20 is punched into a rectangular flat plate shape (5 mm × 50 mm × 2 mm) to produce two sample pieces 40. The surface of each of the sample pieces 40 was cleaned (wiped off) with ethanol, and then fixed with an adhesive on a rectangular flat plate (2 mm × 110 mm × 70 mm) stainless steel plate (SUS plate) 41 at a distance of 60 mm. A surface of 5 mm × 50 mm was fixed).

  Further, a white melamine coating plate 42 having a rectangular flat plate shape (similar to the stainless steel plate 41 and having a thickness of 1.0 mm to 1.5 mm) is placed on the sample piece 40 so as to cover each sample piece 40. Place a weight member 43 of a total of 49N on the coated plate 42 and apply a load (while applying a load to the portion of the painted plate 42 where the sample piece 40 is located) in an atmosphere of 80 ° C. Left for 24 hours.

Thereafter, the weight member 43 is removed (removed immediately before the measurement), and a jig 44 having a substantially L-shaped longitudinal section is interposed between the stainless steel plate 41 and the coating plate 42 (and between each sample piece 40), With the inner corner side of the jig 44 engaged with the end of the coating plate 42 and the stainless steel plate 41 fixed, the jig 44 is moved in the horizontal direction (for each of the fixed specimen pieces 40). When the coated plate 42 and the sample piece 40 are completely peeled by pulling at a speed of 50 mm / min with respect to the longitudinal direction (arrow direction shown in the drawing) (that is, by pulling the coated plate 42 through the jig 44). The maximum load (unit: N / 5 cm ² ) generated was measured as sticking force (hereinafter referred to as initial sticking force), and the sticking resistance was examined.

Further, as described above, the coating plate 42 is placed so as to cover each sample piece 40, and the sample piece 40 is left in the gear oven (80 ° C.) for a total of 200 hours while applying a load by the weight member 43. After the thermal acceleration deterioration treatment, the maximum load (unit: N / 5 cm ² ) generated when the coating plate 42 and the sample piece 40 are completely peeled off by the same method as the initial sticking force is used. This was measured as a post-sticking force.

  Then, using the initial sticking force and the post-deteriorating sticking force, the sticking resistance index ΔS was calculated by the following equation (3), and the sticking resistance persistence (hereinafter referred to as sticking resistance resistance) was examined. .

  “Attachment resistance index ΔS” = “sticking force after deterioration” − “initial sticking force” (3).

The N / 5 cm ² used here is a unit specified by the inventor in order to quantify the peel load with respect to the total contact area of the two sample pieces 40. The “anti-sticking duration index ΔS” and “post-degradation sticking force” are obtained when the heat accelerated deterioration treatment at 80 ° C. for 20 hours is repeated 10 times (that is, the total heat accelerated deterioration treatment time is 200 hours (Arrhenius). This is equivalent to accelerating the number of years elapsed by about 5 years based on the above law))). Furthermore, after each of the 10 thermal accelerated deterioration processes, the process of cleaning the coated plate 42 with ethanol (particularly the process of cleaning the contact surfaces of both), and the surface of the sample piece 40 are made of Crecia Kimwipe (Kimwipe). S-200) to perform a cleaning step (a step of cleaning the surface of the sample piece 40 in one direction so that the Kimwipe containing ethanol is pressed against the sample piece 40 with a load of 0.98 N) Shall be.

[Lubricity, smoothness]
As shown in FIGS. 5A (schematic diagram) and B (variation characteristic diagram), the sample 20 is punched into a rectangular flat plate (5 mm × 100 mm × 2 mm) to produce a sample piece 50. The dirt was wiped off with ethanol and then placed on a support (test stand) 51 of a friction coefficient measuring machine (HEIDON-14D manufactured by Shinto Kagaku). Thereafter, the weight member 52 that is composed of R50 spherical glass and applied with a load of 0.98 N is placed on the sample piece 50 (the R50 spherical surface is placed), and the weight member 52 is placed in the horizontal direction (sample By sliding at a speed of 1000 mm / min with respect to the longitudinal direction of the piece 50 (in the direction of the arrow shown) (sliding while contacting the sample piece 50), for example, an elapsed time as shown in FIG. ) Was obtained, and a static friction coefficient (hereinafter referred to as initial static friction coefficient) and a dynamic friction coefficient (hereinafter referred to as initial dynamic friction coefficient) were measured.

  In addition, by leaving the sample piece 50 in a gear oven (80 ° C.) for a total of 200 hours, the sample piece 50 was subjected to thermal accelerated deterioration treatment, and then the same method as the initial static friction coefficient and initial dynamic friction coefficient, Friction coefficient change characteristics with respect to elapsed time were obtained, and a static friction coefficient (hereinafter referred to as a post-deterioration static friction coefficient) and a dynamic friction coefficient (hereinafter referred to as a post-degradation dynamic friction coefficient) were measured to examine the slipperiness.

  Then, using the initial static friction coefficient and the post-deterioration static friction coefficient (or the initial dynamic friction coefficient and the post-deterioration dynamic friction coefficient), the static friction persistence index Δμs (or the dynamic friction persistence index Δμd) is calculated according to the following equation (4). Sustainability (hereinafter referred to as “sliding sustainability”, which was referred to as “sliding sustainability” and “sliding sustainability”) was examined.

  “Static friction duration index Δμs (or dynamic friction duration index Δμd)” = “deteriorated static friction coefficient (or degraded dynamic friction coefficient)” − “initial static friction coefficient (or initial dynamic friction coefficient)” (4).

  The “static friction duration index Δμs”, “dynamic friction duration index, Δμd”, “post-deterioration static friction coefficient”, and “post-deterioration dynamic friction coefficient” are obtained when the thermal acceleration degradation process at 80 ° C. for 20 hours is repeated 10 times (that is, The result of the heat accelerated deterioration treatment time is 200 hours (equivalent to accelerating the elapsed years by about 5 years based on Arrhenius law). Moreover, the process of cleaning the surface of the sample piece 50 with Crecia Kimwipe (Kimwipe S-200) after every 10 thermal accelerated deterioration processes (Kimwipe containing ethanol is less than 0. 0 with respect to the sample piece 50). It is assumed that the process of cleaning the surface of the sample piece 50 by sweeping in one direction so as to be pressed with a load of 98 N is performed.

  From the results shown in Table 2 above, the following were found.

<Rubber compounds P1 to P4, samples GP1 to GP4>
The rubber compounds P1 to P4 having a general composition (80 nm of carbon and 140 phr) have good kneadability and extrusion moldability, respectively, but samples GP1 to GP1 of the rubber molded body composed of the rubber compounds P1 to P4. When GP4 has no surface treatment layer (sample GP1) or has a small thickness (sample GP2), it can be read that the slipperiness and the sticking resistance are low. If the surface treatment layer is too thick (especially sample GP4), sufficient slipping and sticking resistance (and sliding durability and sticking resistance) can be easily obtained, but the elongation set rate is low and rubber molding is performed. It can be seen that the sag resistance of the body itself deteriorates. Furthermore, even if the surface treatment layer has a general thickness (sample GP3), since application spots and application dripping easily occur, productivity may be deteriorated.

<Rubber compounds P5 to P7 not containing a silicone compound, samples GP5 to GP7>
A rubber compound P5 in which two types of foaming agents are blended in a general blend, a rubber compound P6 in which the blending amount of carbon 80 nm is relatively small, and a rubber blend in which the blending amount of carbon 80 nm is relatively small and no foaming agent is blended The product P7 had good kneadability and extrusion moldability, respectively.

  However, the samples GP5 and GP6 composed of the rubber compounds P5 and P6 had sufficient anti-sticking properties but had low sliding properties and sliding durability. Further, the sample GP7 made of the rubber compound P7 had both low lubricity and anti-sticking property, and low anti-sticking durability.

  From this result, in the case of compounds such as rubber compounds P5 to P7, by adding a foaming agent, sufficient sticking resistance can be obtained without a surface treatment layer in the rubber molded body, but the lubricity is It can be seen that it is low and has low sliding durability.

<Rubber compounds P8 to P14 compounded with silicone compounds, samples GP8 to GP14>
The rubber compound P8 blended with a silicone compound having a viscosity of 100 cSt has low kneading processability, and the rubber compound P9 having a very small amount of carbon 80 nm has both low kneading processability and extrusion processability. On the other hand, the rubber compound P10 having a general compounding, the rubber compound P11 compounding 45 nm of carbon, and the rubber compounds P13 and P14 having a relatively small compounding amount of carbon 80 nm have good kneadability and extrudability, respectively. Met.

  However, the samples GP10 and GP11 composed of the rubber compounds P10 and P11 had sufficient anti-sticking properties, but had low sliding properties and low sliding and anti-sticking properties. In addition, the sample GP12 made of the rubber compound P12 had both low lubricity and sticking resistance, and low sliding durability. Further, the samples GP13 and GP14 made of the rubber compounds P13 and P14 have a very low specific gravity, and compared with the other samples GP1 to GP12, the slipperiness and resistance to sticking are sufficient. Sticking persistence was insufficient.

  From this result, in the blends such as the rubber blends P8 to P14, even if the silicone compound is blended, if the blending amount of the carbon black is too small, the composition of the blend becomes low, and the blend It can be read that the kneadability of the product and the extrusion moldability are lowered (decrease in winding property with respect to rolls, occurrence of variation in discharge, etc.).

  In addition, when the viscosity of the silicone compound is too low, the kneading processability and extrusion moldability of the compound are similarly lowered, and the mobility in the rubber molded body of the silicone compound is large (the bleed speed is too high). Therefore, it can be read that the sliding durability and the sticking durability are low.

  In addition, when the arithmetic average particle size of carbon black is too small, the carbon-derived uneven surface is not formed in the rubber molded body, so that the contact area with the contact target becomes large and the bleed material is easily removed. Can be read.

  Furthermore, it can be seen that when the specific gravity of the rubber molded body is too small (particularly when the foamed cells are excessive), the bleed speed of the silicone compound tends to be slow.

  In addition, it can be read that when the blending amount of the softening agent having adhesiveness is excessive (for example, more than 100 phr), the sticking resistance tends to decrease.

<Rubber compounds S1 to S12, samples GS1 to GS12>
The rubber compounds S1 to S12 each had good kneading processability and extrusion moldability. Samples GS1 to GS12 composed of the rubber compounds S1 to S12 exhibited good lubricity, sticking resistance, sliding durability, sticking resistance, and sag resistance.

  From this result, a compound in which a carbon compound having an arithmetic average particle diameter of 60 nm or more and a silicone compound having a viscosity of 1000 cSt or more is compounded with a carbon compound having an arithmetic average particle diameter of 60 nm or more, such as rubber compounds S1 to S12, has sufficient cohesiveness. I can read. In addition, in the rubber molded body made of the compound, a carbon-derived uneven surface is formed, the contact area with the contact target is reduced, and the bleed material of the silicone compound tends to remain on the carbon-derived uneven surface, It can be seen that good lubricity and sticking resistance persist. Furthermore, it can be seen that when the blending amount of the softening agent is 100 phr or less, there is almost no reduction in sticking resistance.

  Moreover, even if it does not mix | blend a foaming agent, even if it mix | blends one or more types of multiple types of foaming agents selectively, it can read that the same physical property is obtained, respectively. Furthermore, even if the specific gravity of the rubber molded body is too small, if the specific gravity is 0.3 or more, the bleed speed of the silicone compound is sufficient, and good lubricity and resistance to sticking are more stably maintained. I can read that.

  Here, Table 3 below and FIGS. 6A (static friction coefficient) and B (dynamic friction coefficient) are the post-deterioration static friction coefficients measured for each thermal acceleration degradation process (thermal acceleration degradation process time) in the samples GP1, GP3, and GS5. Figure 3 shows the results of post-degradation dynamic friction coefficients.

  In the results shown in Table 3 and FIG. 6, the sample GP3 has good slipperiness (especially, initial slipperiness) because the static friction coefficient after each deterioration and the dynamic friction coefficient after each deterioration are smaller than those of the sample GP1. Since each coefficient has a tendency to increase for each thermal acceleration deterioration process, it can be read that the sliding durability is low.

  On the other hand, in the sample GS5, as in the sample GP3, each coefficient is small and has a good sliding property, and since each coefficient is substantially constant or descending, the sliding durability (static sliding durability, sliding durability) ) Is high.

  It is to be noted that, similarly to the rubber compounds S1 to S12, a rubber compound containing at least another polymer elastic body polymer, carbon black, softener, and silicone compound, and the arithmetic average particle size of the carbon black is Sufficient kneadability and extrusion molding if 60 nm or more (for example, carbon 60 nm, 80 nm), blending amount is 50 phr to 100 phr, blending amount of the softener is 100 phr or less, and viscosity (25 ° C.) of the silicone compound is 1000 cSt or more. It was confirmed that the samples using the rubber compound had sufficiently good slipping properties, sticking resistance, sliding durability, sticking durability, and sag resistance.

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

Explanatory drawing which shows the structural model of the rubber molded object formed by extrusion-molding and vulcanizing a rubber material composition. The schematic explanatory drawing of the sample (GS1-GS12, GP1-GP14) of the rubber molding used in the Example. Explanatory drawing which shows the measuring method of sag resistance in an Example. Explanatory drawing which shows the measuring method of sticking-proof property in an Example. Explanatory drawing which shows the measuring method of the friction coefficient in an Example. Explanatory drawing of the measurement result of the after-deterioration static friction coefficient for every thermal acceleration degradation process in samples GP1, GP3, and GS5, and a dynamic friction coefficient after degradation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Rubber molded object 10a ... Flat surface 10b ... Bleed thing 10c ... Carbon-derived uneven surface 10d ... Removal area 20 ... Sample 30,40,50 ... Sample piece

Claims (6)

Used at least on the surface side of the contact part of the rubber molded body by extrusion molding vulcanization,
At least 100 phr of an ethylene-α-olefin / nonconjugated polyene copolymer, 50 phr to 100 phr of carbon black having an arithmetic average particle size of 60 nm or more, a silicone compound having a viscosity (25 ° C.) of 1000 cSt or more, and a viscosity (25 ° C.) of 1000 cSt or more, A rubber material composition comprising:   2. The rubber material composition according to claim 1, wherein a foaming agent is blended. A rubber molded body obtained by extruding and vulcanizing the rubber material composition according to claim 1,
A carbon-derived uneven surface is formed on at least the surface side of the contact portion of the rubber molded body,
A rubber molded body having a specific gravity of 0.3 or more.   4. The rubber molded article according to claim 3, wherein the static friction duration index [Delta] [mu] s and the dynamic friction duration index [Delta] [mu] d are 0.9 or less and 0.7 or less, respectively, and the sticking resistance duration index [Delta] S is 80 or less. A weather strip for automobiles obtained by extruding and vulcanizing the rubber material composition according to claim 1,
A carbon-derived uneven surface is formed on at least the surface side of the contact portion of the weather strip,
A weather strip for automobiles having a specific gravity of 0.3 or more.   6. The automobile weather strip according to claim 5, wherein the static friction duration index [Delta] [mu] s and the dynamic friction duration index [Delta] [mu] d are 0.9 or less and 0.7 or less, respectively, and the anti-sticking duration index [Delta] S is 80 or less.

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