Appearance improver and rubber composition using the same

Abstract

To provide an appearance improver which enables production of a rubber product improved in appearance without impairing ozone resistance of rubber.SOLUTION: The appearance improver to be used for a rubber material contains (A) a cured product of a natural oil or fat, (B) a vegetable wax, and (C) a nonionic surfactant represented by the following general formula (1). R1O(R2O)nH (1) (where R1 represents a C12-22 alkyl group or alkenyl group; the alkyl group and the alkenyl group may be linear, branched or cyclic; R2 is a C2-4 alkylene group; and n represents an average addition molar number and is 1-15).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an appearance improver and a rubber composition using the same. More specifically, the present invention relates to an appearance improver that can suppress appearance contamination caused by components contained in a rubber material without impairing the ozone resistance of the rubber, and can produce a rubber product with improved appearance, and a rubber composition using the same. [Background technology]

[0002] Rubber is a mixture of various materials, some of which may precipitate on the surface of a rubber product (e.g., a rubber molded product) and impair the appearance of the rubber product. The precipitation of components contained in the rubber material on the surface of a rubber product is sometimes called "bloom" or "blooming."

[0003] Conventionally, crosslinked rubber has been used in many industrial products because of its excellent mechanical properties such as heat resistance and compression set. This crosslinked rubber is generally produced by blending a crosslinking additive such as sulfur, vulcanization accelerator, peroxide, fatty acid, fatty acid metal salt, etc., with a specific polymer to form a crosslinked structure in the polymer. However, the sulfur, vulcanization accelerator, peroxide, and their reaction products required for such crosslinking may precipitate on the rubber surface depending on the blending amount, molding conditions, and usage environment, thereby impairing the commercial value of the rubber product.

[0004] In addition, rubber materials such as tires and rubber mats are used in places exposed to the outside air, so anti-aging ingredients such as antioxidants are sometimes compounded to prevent deterioration due to ozone. Some antioxidants migrate from within the rubber material to its surface and form a coating on the surface of the rubber material, protecting the rubber material from attack by ozone. However, these antioxidants may also precipitate on the rubber surface depending on the type, amount compounded, and usage environment, impairing the commercial value of the rubber product. In particular, when the antioxidant precipitates on the rubber surface, the surface of the rubber product loses its luster and changes color to the color of bloom, impairing the appearance of the rubber product.

[0005] For this reason, various methods have been proposed to suppress blooming of components contained in rubber materials (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6732330 [Patent Document 2] Patent No. 7015051 Summary of the Invention [Problem to be solved by the invention]

[0007] However, although the rubber composition described in Patent Document 1 and the blooming inhibitor described in Patent Document 2 have been confirmed to have a certain effect of suppressing the blooming of the components contained in the rubber material, there is still room for further improvement. In particular, in the conventional technology, emphasis is placed on suppressing blooming, so that the surface of the rubber product is easily exposed to the outside air, and the ozone resistance of the rubber may decrease. In particular, when suppressing the blooming of a specific component such as an anti-aging component, the effect originally expected of the component may not be fully exerted, and there has been a strong demand for the development of an appearance improver that can produce a rubber product with improved appearance without impairing the ozone resistance of the rubber.

[0008] The present invention has been made in consideration of the problems associated with the conventional techniques as described above. The present invention provides an appearance improver that can suppress blooming (precipitation) of contained components without impairing the ozone resistance of rubber, and can produce rubber products with improved appearance, and a rubber composition using the same. [Means for solving the problem]

[0009] According to the present invention, there are provided the following appearance improver and rubber composition.

[0010] [1] An appearance improver for use in rubber materials, comprising (A) a hardened product of a natural fat or oil, (B) a vegetable wax, and (C) a nonionic surfactant represented by the following general formula (1): R 1 O(R 2 O) n H (1) (In the above general formula (1), R 1 represents an alkyl group or an alkenyl group having 12 to 22 carbon atoms, and the alkyl group and the alkenyl group may be linear, branched, or cyclic; R 2 is an alkylene group having 2 to 4 carbon atoms, and n means the average number of moles added and is 1 to 15.

[0011] [2] The appearance improver according to [1], wherein, relative to a total of 100% by mass of the (A) hardened product of natural fats and oils, the (B) vegetable wax, and the (C) nonionic surfactant represented by general formula (1), the (A) hardened product of natural fats and oils accounts for 50 to 90% by mass, the (B) vegetable wax accounts for 0.5 to 20% by mass, and the (C) nonionic surfactant represented by general formula (1) accounts for 0.5 to 30% by mass.

[0012] [3] The appearance improver according to [1] or [2], wherein the (A) hardened natural oil or fat contains hardened castor oil.

[0013] [4] The appearance improving agent according to [1] or [2], wherein the (B) vegetable wax is a vegetable wax obtained from a plant of the genus Carbomer in the family Palmaceae.

[0014] [5] The appearance improving agent according to [4], wherein the plant wax extracted from the palm family plant of the genus Carnauba is carnauba wax.

[0015] [6] The appearance improver according to [1] or [2] above, A rubber material including a rubber component.

[0016] [7] The rubber composition according to [6], wherein the blending amount of the appearance improver is 0.5 to 5.0 parts by mass per 100 parts by mass of the rubber component in the rubber material. Effect of the Invention

[0017] The appearance improver of the present invention has the effect of suppressing appearance staining caused by components contained in a rubber material without impairing the ozone resistance of the rubber, and improving appearance staining caused by bloom in the produced rubber product.

[0018] The rubber composition of the present invention is a raw material for rubber products, and has the effect of suppressing blooming of components contained in the rubber material (e.g., anti-aging components and crosslinking additives) on the surface of the manufactured rubber product, thereby making it possible to produce rubber products that have excellent ozone resistance and improved appearance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The following describes the embodiments of the present invention, but the present invention is not limited to the following embodiments. In other words, it should be understood that the scope of the present invention includes any modifications and improvements to the following embodiments based on the ordinary knowledge of a person skilled in the art without departing from the spirit of the present invention.

[0020] (1) Appearance improver: One embodiment of the appearance improver of the present invention is an appearance improver that is added to a rubber material containing a rubber component. The appearance improver of this embodiment contains (A) a hardened product of natural fats and oils (hereinafter also referred to as "component (A)"), (B) a vegetable wax (hereinafter also referred to as "component (B)"), and (C) a nonionic surfactant represented by the following general formula (1) (hereinafter also referred to as "nonionic surfactant (C)" or "component (C)").

[0021] R 1 O(R 2 O) n H (1) (In the above general formula (1), R1 represents an alkyl group or an alkenyl group having 12 to 22 carbon atoms, and the alkyl group and the alkenyl group may be linear, branched, or cyclic; R 2 is an alkylene group having 2 to 4 carbon atoms, and n means the average number of moles added and is 1 to 15.

[0022] Such an appearance improver suppresses the blooming (precipitation) of components other than the rubber component, such as various additives contained in the rubber material, on the surface of the rubber product. In other words, by blending the appearance improver of the present invention, it is possible to produce an improved rubber product that prevents "the appearance of components other than the rubber component from being contaminated by blooming." In particular, the appearance improver contains a hardened product of natural fats and oils as component (A), a vegetable wax as component (B), and a nonionic surfactant represented by the above general formula (1) as component (C), thereby suppressing the blooming (precipitation) of components contained in the rubber material without impairing the ozone resistance of the rubber, and improving the appearance contamination caused by blooming in the produced rubber product.

[0023] For example, by adding the appearance improver of this embodiment to a rubber material containing an antiaging agent, the bloom of the antiaging component contained in the antiaging agent can be effectively suppressed. Wax, which is one of the antiaging agents, is an additive used to prevent rubber deterioration (e.g., cracking of rubber) caused by ozone, and petroleum-derived paraffin wax and microcrystalline wax are widely used as antiaging components. Antiaging components such as wax bloom (i.e., migrate from within the rubber material to its surface) to form a coating on the surface of the rubber material, thereby preventing the rubber material from being attacked by ozone. For this reason, if the bloom of the petroleum-derived wax as an antiaging component is suppressed, the rubber surface becomes more easily exposed to ozone, and the ozone resistance of the rubber may decrease. The appearance improver of this embodiment contains a vegetable wax as component (B), so that the bloom of the antiaging component can be further suppressed and the deterioration of the appearance can be prevented.

[0024] In addition, by containing the appearance improver of this embodiment, the surface of the coating of the anti-aging component formed on the surface of the rubber product becomes flat (i.e., the degree of unevenness on the surface of the coating becomes small), and when light hits the coating, the light is prevented from being diffusely reflected and appearing white, which can improve the appearance of black rubber products such as tires in particular.

[0025] In addition, the appearance improver of the present embodiment can suppress the blooming (precipitation) of crosslinking additives such as vulcanization accelerators, peroxides, fatty acids, and fatty acid metal salts on the surface of rubber products. In other words, by adding the appearance improver, it is possible to produce rubber products that are improved so as to prevent "blooming of crosslinking additives and contamination of the appearance."

[0026] (1-1)(A) Component: Component (A) is a hardened product of natural fats and oils. In this way, the appearance improver contains a natural fat and oil component consisting of a hardened product of natural fats and oils as an essential component. Here, in the appearance improver of this embodiment, the "hardened product of natural fats and oils" of component (A) is obtained by hydrogenating the unsaturated bonds of natural fats and oils, which are natural products, and hardening the natural fat and oil by chemically changing the structure of the natural fat and oil. In other words, component (A) is a hydrogenated hardened product of natural fats and oils. For this reason, the "hardened product of natural fats and oils" of component (A) corresponds to a so-called "synthetic wax", and in particular can be said to be an "oil-based synthetic wax" made from natural fats and oils.

[0027] Examples of the hardened natural fats and oils in the natural fat and oil component include hardened castor oil (12-hydroxystearic acid triglyceride), hardened soybean oil, hardened rapeseed oil, and hardened beef tallow oil. Among the hardened natural fats and oils, it is preferable to use hardened castor oil. The natural fat and oil component may contain one or more of the above components.

[0028] (1-2)(B) Component: Component (B) is a vegetable wax. The vegetable wax is a wax derived from a plant. By including such a vegetable wax, it is possible to significantly improve the appearance staining of a rubber product without impairing the ozone resistance of the rubber, particularly in cases where a petroleum-derived wax is used as an antiaging agent in a rubber material.

[0029] Here, wax means an oily substance, and is roughly classified into two types: natural wax and synthetic wax. In addition, among natural waxes, those derived from animals and plants are sometimes called "wax". In addition, natural waxes can be classified into plant wax, animal wax, mineral wax, petroleum wax, etc. according to their origin, and "plant wax" in this specification means wax derived from plants among the above-mentioned classifications. Note that natural waxes such as plant wax and animal wax are substances themselves collected from natural products or those that have been refined by removing impurities, and have the original chemical structure of the collected substance, and are not processed by hydrogenation or the like like the hardened product of natural oils and fats of component (A). Petroleum wax is wax obtained from a petroleum refining process, and is, for example, a wax mainly composed of paraffin. On the other hand, synthetic wax refers to wax that has been artificially produced or that has been chemically changed by processing such as the above-mentioned hydrogenation. In this specification, wax refers to an organic substance that is solid to semi-solid at room temperature and normal pressure and has a melting point between room temperature and 100°C.

[0030] There is no restriction on the type of plant wax as component (B). Although not particularly limited, examples of plant wax as component (B) include those containing esters of higher fatty acids and higher alcohols. Specific examples of plant wax include carnauba wax, rice wax, candelilla wax, sunflower wax, montan wax, haze wax, urushi wax, hakuro wax, and sugarcane wax. As the plant wax as component (B), the above-mentioned plant-derived waxes can be used alone or in combination of two or more kinds.

[0031] The plant wax as component (B) preferably contains a plant wax obtained from a palm plant of the genus Carnauba. Compared to other plant waxes, the plant wax obtained from such a palm plant of the genus Carnauba is superior in that it can maintain the gloss of rubber for a long period of time. An example of the plant wax obtained from a palm plant of the genus Carnauba is carnauba wax. The carnauba wax is preferably No. 1 carnauba wax.

[0032] The appearance improver of this embodiment contains vegetable wax as component (B), but even if a synthetic wax such as polyethylene wax is added to the appearance improver, the effect of improving the appearance staining of rubber products without impairing the ozone resistance of the rubber cannot be obtained. On the contrary, when polyethylene wax is added, the dropping point of the petroleum wax added as an anti-aging agent in the rubber material increases. As a result, the anti-aging agent (petroleum wax) dispersed in the rubber material is less likely to migrate to the rubber surface compared to a rubber material not containing such polyethylene wax, and the barrier effect against ozone on the rubber surface (i.e., the original effect as an anti-aging agent) is less likely to be exhibited.

[0033] (1-3)(C) Component: The component (C) is a nonionic surfactant represented by the above general formula (1). 1 is an alkyl group having 12 to 22 carbon atoms or an alkenyl group having 12 to 22 carbon atoms, preferably an alkyl group having 14 to 20 carbon atoms, and more preferably an alkyl group having 16 to 18 carbon atoms. Such component (C) may be used alone or in combination of two or more types.

[0034] The nonionic surfactant represented by the general formula (1) is 2 is an alkylene group having 2 to 4 carbon atoms, preferably an alkylene group having 2 to 3 carbon atoms, and more preferably an alkylene group having 2 carbon atoms. 2 is not limited to one type, and may be two or more types.

[0035] In general formula (1), n ​​is 1 to 15, preferably 1 to 10, and more preferably 1 to 6, from the viewpoint of improving compatibility with antiaging components and crosslinking additives that may bloom on the surface of rubber products.

[0036] (1-4) Appearance improver formulation: In the appearance improver, the hardened product of natural fats and oils (A), the vegetable wax (B), and the nonionic surfactant represented by general formula (1) (C) are preferably blended at a predetermined ratio. Specifically, in the appearance improver, the blending ratio of the hardened product of natural fats and oils (A) is preferably 50 to 90 mass%, and more preferably 75 to 90 mass%, of the total of the components (A), (B), and (C) being 100 mass%. The upper limit of the blending ratio is not particularly limited, but may be, for example, 85 mass% or 80 mass%. The lower limit of the blending ratio may be, for example, 60 mass% or 70 mass%. In the appearance improver, the blending ratio of the vegetable wax (B) is preferably 0.5 to 20 mass%, more preferably 5 to 20 mass%, and particularly preferably 10 to 15 mass%. Furthermore, in the appearance improver, the blending ratio of the nonionic surfactant represented by general formula (1) of component (C) is preferably 0.5 to 30 mass%, more preferably 1 to 20 mass%, and particularly preferably 5 to 15 mass%. If the respective components are out of this range, the effect of improving the appearance by reducing the surface irregularities of the rubber product caused by blooming without impairing the ozone resistance of the rubber cannot be fully obtained, and there is a tendency for the blending of the appearance improver to cause discoloration of the rubber surface, deterioration of the physical properties of the rubber molded product, and deterioration of the function of the blended antioxidant.

[0037] The total content of components (A), (B), and (C) in the appearance improver of the present invention is 90% by mass or more, and preferably 95% by mass or more. If the total content of components (A), (B), and (C) is less than 90% by mass, a sufficient blooming suppression effect may not be obtained, and discoloration due to the blending of the appearance improver, deterioration in the physical properties of the rubber molded product, and deterioration in the function of the blended antioxidant may occur.

[0038] (1-5) Rubber material: The appearance improver of the present invention exerts a blooming suppression effect in the obtained rubber product by being added to a rubber material. Here, in this specification, what contains the appearance improver of the present invention and a rubber material is a rubber composition, and a rubber product can be manufactured using this rubber composition as a raw material. For example, the appearance improver of the present invention can be kneaded into a rubber material and used as a rubber composition. By molding such a rubber composition, it is possible to suppress contamination that appears on the rubber surface due to these compounds, and to maintain the commercial value of the rubber molded product (rubber product).

[0039] The rubber material contains a rubber component which is a main material for producing a rubber product. In addition to the rubber component, the rubber material may contain various additives such as antioxidants and crosslinking additives. The appearance improver of the present invention suppresses blooming (precipitation) of specific components contained in such additives, and improves appearance contamination caused by blooming in a rubber molded product (rubber product).

[0040] (1-5a) Rubber component: The rubber component is the main raw material for rubber products such as tires and rubber mats. There are no particular limitations on the rubber component, and examples of the rubber component include natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, butyl rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, hydrogenated acrylonitrile-butadiene rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, silicone rubber, urethane rubber, polysulfide rubber, and fluororubber. These rubber components may be used alone or in combination of two or more.

[0041] (1-5b) Anti-aging agents: Antiaging agents are used to prevent the aging of rubber products. These antiaging agents are added to rubber products to form a protective film on the surface of the rubber product to prevent the rubber product from being attacked by ozone. Specific examples of "antiaging agents" include petroleum-derived waxes (petroleum waxes) and other antiaging agents other than petroleum-derived waxes. Examples of petroleum-derived waxes include paraffin wax and microcrystalline wax. Examples of other antiaging agents include naphthylamine-based, diphenylamine-based, p-phenylenediamine-based, quinoline-based, hydroquinone derivative-based, mono-, bis-, tris- or poly-phenol-based, thiobisphenol-based, hindered phenol-based, phosphorous acid ester-based, imidazole-based, nickel dithiocarbamate-based, and phosphoric acid-based antiaging agents. These antiaging agents can be used alone or in combination of two or more.

[0042] (1-5c) Crosslinking additives: The crosslinking additive is at least one selected from the group consisting of vulcanization accelerators, peroxides, fatty acids, and fatty acid metal salts. These are used to form a crosslinked structure in a polymer during the production of crosslinked rubber, and are conventionally known. The appearance improver of the present invention can suppress blooming of any of the vulcanization accelerators, peroxides, fatty acids, and fatty acid metal salts.

[0043] (2) Rubber composition: The rubber composition of the present invention contains the appearance improver of the present invention and a rubber material containing a rubber component.

[0044] When a rubber product is manufactured using the rubber composition as a raw material, such a rubber composition prevents the antioxidants, such as the petroleum-derived wax described above, and crosslinking additives, such as vulcanization accelerators, peroxides, fatty acids, and fatty acid metal salts, contained in the rubber product from blooming to the surface.

[0045] The rubber material may be the same as the rubber material described above in relation to the appearance improver of the present invention.

[0046] The blending amount of the appearance improver is preferably 0.5 to 5.0 parts by mass, more preferably 1.0 to 4.0 parts by mass, and particularly preferably 1.5 to 2.5 parts by mass, based on 100 parts by mass of the rubber component in the rubber material. By setting the blending amount of the appearance improver within the above range, blooming of the contained components can be effectively suppressed without impairing the ozone resistance of the rubber. If the blending amount of the appearance improver is less than the lower limit, the amount of blooming of the contained components may increase. If the blending amount of the appearance improver exceeds the upper limit, the appearance improver itself may bloom excessively, discoloration due to the blending of the appearance improver, deterioration of the physical properties of the rubber molded product, and deterioration of the function of the blended antioxidant may occur.

[0047] The rubber composition of the present invention may further contain other components in addition to the rubber material and the appearance improver, such as antioxidants, crosslinking additives, reinforcing agents, fillers, plasticizers, softeners, UV absorbers, flame retardants, antibacterial and antifungal agents, colorants, etc. EXAMPLES

[0048] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0049] (Examples 1 to 27, Comparative Examples 1 to 26) (1) Preparation of appearance improver: Appearance improvers were prepared by pre-mixing the samples shown in Tables 1 to 6. The blending amounts of the appearance improvers shown in Tables 1 to 6 indicate the blending amounts (parts by mass) per 100 parts by mass of the rubber component (natural rubber (RSS#1)) in the rubber material described below.

[0050] (2) Preparation of rubber material: First, 100 parts by mass of natural rubber (RSS#1), 5 parts by mass of zinc oxide type 1, 2 parts by mass of stearic acid, 50 parts by mass of FEF carbon black, 10 parts by mass of naphthenic oil, and 2 parts by mass of "Suntite S" (wax manufactured by Seiko Chemical Industry Co., Ltd.) were kneaded for 3.5 minutes in a 1.7 L Banbury mixer. Next, 2 parts by mass of powdered sulfur and 1.3 parts by mass of "Suncerer CM" (vulcanization accelerator manufactured by Sanshin Chemical Industry Co., Ltd.) were added to the kneaded mixture using two open rolls with a diameter of 24 cm, and further kneaded to obtain a rubber material as a master batch.

[0051] (3) Preparation and evaluation of rubber compositions: To the obtained rubber material, an "appearance improver" shown in Tables 1 to 6 was added, and further kneaded to obtain an unvulcanized rubber composition.

[0052] The unvulcanized rubber composition thus obtained was subjected to vulcanization molding using a press to obtain a vulcanized rubber sheet (rubber product) having a thickness of 2.0 mm. The vulcanized rubber sheet thus obtained was subjected to a static ozone degradation test and an appearance evaluation test.

[0053] (Static ozone degradation test) A static ozone degradation test was carried out using the obtained vulcanized rubber sheet. First, a No. 1 dumbbell-shaped test piece was punched out from the vulcanized rubber sheet and used as a sample. The static ozone degradation test was carried out using an ozone tester (manufactured by Suga Test Instruments Co., Ltd. under the trade name "OMS-L"). In this test, the ozone concentration was set to 50 pphm, the temperature inside the layer was set to 40°C, the sample elongation rate was set to 20%, and the test time was set to 24 hours. After 24 hours, the sample was observed with a 10x magnifying glass and the naked eye, and was evaluated based on the following evaluation criteria. The evaluation results of the static ozone degradation test for each of the examples and comparative examples are shown in Tables 1 to 6.

[0054] <Evaluation criteria for static ozone degradation tests> A: No cracks caused by ozone were observed. B: A few fine cracks visible with a magnifying glass. C: A few cracks are visible to the naked eye. D: Large cracks or multiple cracks are visible to the naked eye. E: Deep cracks or numerous cracks or fractures in the sample are visible to the naked eye. In the static ozone degradation test, ratings of A and B were considered to be passing.

[0055] (Appearance evaluation test) The vulcanized rubber sheet obtained was used to carry out an appearance evaluation test. Specifically, the state of the following two types of samples (sample 1 and sample 2) from the obtained vulcanized rubber sheet after 28 days was evaluated. Sample 1 was a sample obtained by leaving the obtained vulcanized rubber sheet at rest in an environment of 25°C. Sample 2 was a sample obtained by giving 20% ​​elongation once with an autograph (manufactured by Shimadzu Corporation under the trade name "AGS-500NJ") to promote blooming of the vulcanized rubber sheet, and then leaving it at rest at 25°C. The evaluation method consisted of visually observing the appearance of the above-mentioned samples 1 and 2, and measuring the glossiness using a gloss checker (manufactured by Horiba, Ltd. under the trade name "IG-310"). The visual observation of the appearance was evaluated based on the following evaluation criteria. The glossiness was measured at a measurement angle of 60 degrees. The higher the glossiness value, the better the glossiness.

[0056] <Evaluation criteria for visual appearance observation> Excellent: No change in gloss or color Good: Some loss of gloss and discoloration. Pass: Loss of gloss and discoloration are observed. Unacceptable: Significant loss of gloss and discoloration. The evaluation criteria for visual appearance observation were excellent and good, and for gloss measurement, a gloss of 80 or more was considered to be a pass.

[0057] In Tables 1 to 6, "Component (A)" corresponds to "hardened product of natural fats and oils". "Component (B)" corresponds to "vegetable wax". "Component (C)" corresponds to "nonionic surfactant represented by general formula (1)". "Component (B')" refers to "synthetic polyethylene wax" other than vegetable wax. "Component (C')" refers to nonionic surfactant other than the nonionic surfactant represented by general formula (1).

[0058] The details of each component are as follows.

[0059] (A) Component: Castor oil (12-hydroxystearic acid triglyceride): Manufactured by KF Trading Co., Ltd. Hardened rapeseed oil: Manufactured by Nitto Bussan Shoji Co., Ltd. Hydrogenated soybean oil: Manufactured by Nitto Bussan Shoji Co., Ltd. Hydrogenated beef tallow oil: Manufactured by NOF Corporation.

[0060] (B) Ingredients: Refined Carnauba Wax No. 1: Manufactured by Cerarica NODA. Refined rice wax: Made by Cerarica NODA. Candelilla wax: Made by Cerarica NODA. Sunflower wax: Manufactured by Yamakei Sangyo Co., Ltd.

[0061] (B') Component: Sanwax 151-P: Polyethylene wax, manufactured by Sanyo Chemical Industries, Ltd. Hiwax 720P: Polyethylene wax, manufactured by Mitsui Chemicals.

[0062] (C) Ingredients: Nonion S202: In the above general formula (1), R 1 C 18 H 35 , R 2 C2H 4、 n is 2, manufactured by NOF Corporation. Emulgen 306P: In the above general formula (1), R 1 C 18 H 37 , R 2 C2H 4、 n is 6, manufactured by Kao Corporation. Emulgen 404: In the above general formula (1), R 1 C 18 H 35 , R 2 C2H 4、 n is 4, manufactured by Kao Corporation.

[0063] (C') component: Rheodol SP-O10V: A nonionic surfactant represented by the following general formula (2), in which R 1 C 18 H 36Manufactured by Kao Corporation. Newpol PE61: A nonionic surfactant represented by the following general formula (3), 1 is C2H4, R 2 is C3H6, n is 1750, m is 250, manufactured by Sanyo Chemical Industries.

[0064] [ka]

[0065] OH(R 1 O) n (R 2 O) m H (3)

[0066] [Table 1]

[0067] [Table 2]

[0068] [Table 3]

[0069] [Table 4]

[0070] [Table 5]

[0071] [Table 6]

[0072] (result) From the results in Tables 1 to 3, the appearance improvers of Examples 1 to 27 showed good results in the static ozone degradation test, and also all showed good results in the appearance evaluation test.

[0073] On the other hand, from the results of Tables 4 to 6, the appearance improvers of Comparative Examples 2 to 4 had low gloss both at 25°C and at 20% elongation in the appearance evaluation test. The appearance improvers of Comparative Examples 5 to 13, 20 to 22, and 25 were confirmed to have a significant decrease in ozone resistance in the static ozone degradation test, and some of the comparative examples also had low gloss. Furthermore, the appearance improvers of Comparative Examples 15 to 19 and 23 to 24 also had visual appearance observation results of either pass or fail, or had low gloss both at 25°C and at 20% elongation in the appearance evaluation test. Furthermore, the appearance improvers of Comparative Examples 15 to 19 and 23 to 24 were rated B or C in the static ozone degradation test, and in particular, Comparative Examples 18 and 19 were rated C and failed the static ozone degradation test. [Industrial Applicability]

[0074] The appearance improver of the present invention can be used as an appearance improver that suppresses blooming by being blended into a rubber composition that is a material for producing rubber products such as tires. The rubber composition of the present invention can also be used as a material for producing rubber products such as tires.

Claims

1. (A) a hardened product of a natural fat or oil; (B) vegetable wax; (C) An appearance improver for use in a rubber material, comprising a nonionic surfactant represented by the following general formula (1): R １ O(R ２ O) ｎ H (1) (In the above general formula (1), R １ represents an alkyl group or an alkenyl group having 12 to 22 carbon atoms, and the alkyl group and the alkenyl group may be linear, branched, or cyclic; R ２ is an alkylene group having 2 to 4 carbon atoms, and n means the average number of moles added and is 1 to 15.

2. 2. The appearance improver according to claim 1, wherein, relative to a total of 100% by mass of the (A) hardened product of natural fats and oils, the (B) vegetable wax, and the (C) nonionic surfactant represented by general formula (1), a blending ratio of the (A) hardened product of natural fats and oils is 50 to 90% by mass, a blending ratio of the (B) vegetable wax is 0.5 to 20% by mass, and a blending ratio of the (C) nonionic surfactant represented by general formula (1) is 0.5 to 30% by mass.

3. The appearance improver according to claim 1 or 2, wherein the (A) hardened product of a natural oil or fat contains hardened castor oil.

4. The appearance improving agent according to claim 1 or 2, wherein the (B) vegetable wax is a vegetable wax obtained from a plant of the genus Carbomer of the family Palmaceae.

5. The appearance improving agent according to claim 4, wherein the plant wax collected from the palm family is carnauba wax.

6. The appearance improver according to claim 1 or 2, A rubber material including a rubber component.

7. The rubber composition according to claim 6, wherein the blending amount of the appearance improver is 0.5 to 5.0 parts by mass per 100 parts by mass of the rubber component in the rubber material.

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