Rubber composition, rubber vulcanized molded product, and method for producing rubber vulcanized molded product

Abstract

The present invention provides a rubber composition containing a volatile component and having excellent durability of the effects of the volatile component, a rubber vulcanization molded article, and a method for producing the rubber vulcanization molded article. [Solution] The rubber composition contains 100 parts by mass of a rubber polymer (A) whose main component is natural rubber, 0.3 to 5 parts by mass of a crosslinking agent (B) in terms of sulfur, 20 to 70 parts by mass of a volatile component-containing agent (C) in terms of volatile components, 0.5 to 3 parts by mass of tetrakis(2-ethylhexyl)thiuram disulfide (D), and 0.5 to 4 parts by mass of a mixture (E) of 80% by mass of dicyclohexylamine salt of ethylene glycol and 20% by mass of a long-chain alkyl alcohol.

Description

[Technical Field]

[0001] The present disclosure relates to a rubber composition, a rubber vulcanizate molded article, and a method for producing a rubber vulcanizate molded article. [Background technology]

[0002] Conventionally, repellents containing repellent components such as wood tar have been commercially available as a countermeasure against animal damage, and are known to have a certain degree of repellent effect.

[0003] For example, Patent Document 1 discloses an animal repellent that contains at least 20 to 70 parts by mass of wood tar, 1 to 5 parts by mass of garlic, and 90 parts by mass or more of natural materials, per 100 parts by total mass, and is in granular, solid, or liquid form. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-210791 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned repellents contain a volatile repellent component as an active ingredient, and exert their repellent effect by evaporating the repellent component. However, for example, simply spraying a liquid repellent outdoors poses a problem in terms of the durability of the effect. In other words, there is a need to develop a technology that can improve the durability of the effect of functional agents that contain a volatile component such as a repellent component as an active ingredient.

[0006] Therefore, an object of the present disclosure is to provide a rubber composition that contains a volatile component and that has excellent durability of the effects of the volatile component, a rubber vulcanization molded article, and a method for producing a rubber vulcanization molded article. [Means for solving the problem]

[0007] In order to solve the above problems, one embodiment of the rubber composition disclosed herein comprises: A rubber polymer (A) mainly composed of natural rubber: 100 parts by mass; Crosslinking agent (B): 0.3 to 5 parts by mass in terms of sulfur, Volatile component-containing agent (C): 20 to 70 parts by mass in terms of volatile components, Tetrakis(2-ethylhexyl)thiuram disulfide (D): 0.5 to 3 parts by mass, and 0.5 to 4 parts by mass of a mixture (E) of 80% by mass of dicyclohexylamine salt of ethylene glycol and 20% by mass of a long-chain alkyl alcohol. It is characterized by:

[0008] A vulcanized rubber molded article obtained by molding and curing the rubber composition of the present invention is excellent in sustained release of volatile components. In other words, according to the present invention, a vulcanized rubber molded article having excellent sustained effect of volatile components can be obtained.

[0009] The volatile component of the volatile component-containing agent (C) is preferably a repellent component.

[0010] The rubber composition of this configuration contains a repellent component as a volatile component, and therefore can provide a vulcanized rubber molded article that is excellent in the sustained release of the repellent component and in the durability of the repellent effect.

[0011] In the rubber composition, the content of the volatile components of the volatile component-containing agent (C) is preferably 15% by mass or more and 40% by mass or less.

[0012] The rubber composition of this configuration can provide a vulcanized rubber molded article that has excellent durability of the effect of volatile components.

[0013] Furthermore, it is preferable that the filler (F) is contained in an amount of 15 to 25 parts by mass.

[0014] According to this configuration, a vulcanized rubber molded article having excellent strength and durability can be obtained.

[0015] One embodiment of the vulcanized rubber molded article disclosed herein is made from the above-mentioned rubber composition.

[0016] The vulcanized rubber molded article of this configuration is excellent in the sustained release of volatile components, and the effects of the volatile components are excellent in durability.

[0017] The number of days required to reduce the amount of volatile components by 1% by mass is preferably 15 days or more.

[0018] According to this configuration, the sustained release of the volatile component is excellent, and the effect of the volatile component is excellent in duration.

[0019] One aspect of the method for producing a vulcanized rubber molded article disclosed herein is to A method for producing a vulcanized rubber molded product, comprising: a kneading step of obtaining a rubber composition by kneading at least 100 parts by mass of a rubber polymer (A) mainly composed of natural rubber, 0.3 to 5 parts by mass of a crosslinking agent (B) in terms of sulfur, 20 to 70 parts by mass of a volatile component-containing agent (C) in terms of volatile components, 0.5 to 3 parts by mass of tetrakis(2-ethylhexyl)thiuram disulfide (D), and 0.5 to 4 parts by mass of a mixture (E) of 80% by mass of a dicyclohexylamine salt of ethylene glycol and 20% by mass of a long-chain alkyl alcohol; a vulcanization molding step of vulcanizing the rubber composition to obtain the vulcanized rubber molded article, the temperature of the kneaded mixture after adding the volatile component-containing agent (C) in the kneading step is 100°C or less; The vulcanization temperature in the vulcanization molding process is 140°C or less. It is characterized by:

[0020] According to this configuration, it is possible to suppress the evaporation of volatile components during the kneading step and the vulcanization molding step. [Effects of the Invention]

[0021] As described above, the vulcanized rubber molded article obtained by molding and curing the rubber composition according to the present disclosure has excellent sustained release properties of volatile components, and therefore the effects of the volatile components are maintained for an extended period of time. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is a flow diagram illustrating a method for producing a rubber vulcanization molded article according to the present disclosure. [Figure 2] FIG. 4 is a diagram for explaining details of a kneading step. [Figure 3] 1A and 1B are a plan view and a side view showing an example of a rubber vulcanization molded article according to the present disclosure. [Figure 4] 3A and 3B are a plan view and a side view showing another example of a rubber vulcanization molded article according to the present disclosure. [Figure 5] 2 is a graph showing the results of a volatility evaluation test of a volatile component-containing agent (C-1). [Figure 6] 4 is a graph showing the relationship between vulcanization temperature and vulcanization time for the rubber compositions of Experimental Examples 1 to 6. [Figure 7] 1 is a graph showing the effect duration of the sample of Experimental Example 4 and the volatile component-containing agent (C-1). [Figure 8] 1 is a graph showing the effect duration of the sample of Experimental Example 7 and the volatile component-containing agent (C-2). [Figure 9] Graph showing the duration of effect of samples from Experimental Examples 4, 8, and 9. [Figure 10] Graph showing the effect duration of samples of Experimental Examples 9 and 10-12. [Figure 11] Photographs showing the stain resistance test results of the sample of Experimental Example 13 and the volatile component-containing agent (C-3). [Figure 12] FIG. 2 is a perspective view showing another example of a rubber vulcanization molded article according to the present disclosure. [Figure 13] FIG. 13 is a front view of the rubber vulcanization molded article of FIG. [Figure 14] FIG. 13 is a left side view of the rubber vulcanization molded article of FIG. 12. [Figure 15] FIG. 13 is a plan view of the rubber vulcanization molded article of FIG. [Figure 16] FIG. 2 is a perspective view showing another example of a rubber vulcanization molded article according to the present disclosure. [Figure 17] FIG. 17 is a front view of the rubber vulcanization molded article of FIG. 16. [Figure 18] FIG. 17 is a left side view of the rubber vulcanization molded body of FIG. 16. [Figure 19]FIG. 17 is a plan view of the rubber vulcanization molded article of FIG. 16. [Figure 20] FIG. 2 is a perspective view showing another example of a rubber vulcanization molded article according to the present disclosure. [Figure 21] FIG. 21 is a front view of the rubber vulcanization molded article of FIG. 20. [Figure 22] FIG. 21 is a left side view of the rubber vulcanization molded body of FIG. 20. [Figure 23] FIG. 21 is a plan view of the rubber vulcanization molded body of FIG. 20. [Figure 24] FIG. 2 is a perspective view showing another example of a rubber vulcanization molded article according to the present disclosure. [Figure 25] FIG. 25 is a front view of the rubber vulcanization molded article of FIG. 24. [Figure 26] FIG. 25 is a left side view of the rubber vulcanization molded body of FIG. 24. [Figure 27] FIG. 25 is a plan view of the rubber vulcanization molded body of FIG. 24. [Figure 28] FIG. 2 is a perspective view showing another example of a rubber vulcanization molded article according to the present disclosure. [Figure 29] FIG. 29 is a front view of the rubber vulcanization molded body of FIG. 28. [Figure 30] FIG. 29 is a left side view of the rubber vulcanization molded body of FIG. 28. [Figure 31] FIG. 29 is a plan view of the rubber vulcanization molded body of FIG. 28. [Figure 32] FIG. 2 is a perspective view showing another example of a rubber vulcanization molded article according to the present disclosure. [Figure 33] FIG. 33 is a front view of the rubber vulcanization molded body of FIG. 32. [Figure 34] FIG. 33 is a left side view of the rubber vulcanization molded body of FIG. 32. [Figure 35] FIG. 33 is a plan view of the rubber vulcanization molded body of FIG. 32. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0024] <Rubber composition> The rubber composition according to the present disclosure is an unvulcanized rubber composition and contains the following components (A) to (E). The rubber composition may further contain component (F). The rubber composition may further contain component (G).

[0025] <Rubber polymer (A)> The rubber polymer (A) is a polymer component primarily composed of natural rubber (NR). In this specification, "primarily composed of natural rubber (NR)" means that the rubber polymer (A) is composed solely of NR, or, when the rubber polymer (A) is a mixture containing multiple polymer components, that NR accounts for the largest proportion of the multiple polymer components. Preferably, the NR content in the rubber polymer (A) is 50% by mass or more.

[0026] The rubber polymer (A) may contain, in addition to NR, a polymer other than NR. Examples of such polymers other than NR include isoprene rubber (IR), ethylene propylene rubber (EPDM), styrene butadiene rubber (SBR), butadiene rubber (BR), butyl rubber (IIR), chloroprene rubber (CR), and nitrile rubber (NBR). The rubber polymer (A) may contain one or more polymers other than NR.

[0027] <Crosslinking agent (B)> The crosslinking agent (B) is an essential component contained in the rubber composition, and examples thereof include sulfur, tetramethylthiuram disulfide (TMTD), dipentamethylenethiuram tetrasulfide (DPTT), morpholine disulfide (DTDM), etc. The crosslinking agent (B) is not particularly limited, and generally known commercially available products can be used.

[0028] <Volatile component-containing agent (C)> The volatile component-containing agent (C) is a liquid or solid substance containing a volatile component, which will be described later, as an active ingredient. The volatile component-containing agent (C) may be the volatile component itself, or may contain various additives in addition to the volatile component. The volatile component-containing agent (C) preferably contains the volatile component in a proportion of, for example, 5% by mass or more. The volatile component-containing agent (C) is not particularly limited, and generally known substances or commercially available products can be used.

[0029] [Volatile components] Volatile components are substances that have the property of gradually volatilizing at room temperature and normal pressure (also referred to as "volatile" in this specification), and exist as a liquid or solid at room temperature and normal pressure. The boiling point of the volatile components is 60°C or higher and 300°C or lower, preferably 70°C or higher and 200°C or lower, at normal pressure. Substances with a boiling point of less than 60°C at normal pressure may be too volatile, making it difficult to produce the rubber vulcanization molded article according to this embodiment, or may make it impossible to ensure sufficient sustained release properties for the rubber vulcanization molded article. Substances with a boiling point of more than 300°C at normal pressure may not be sufficiently volatile.

[0030] The volatile component is not particularly limited as long as it is a substance having the above-mentioned volatility, and generally known substances such as repellent components, insect repellent components, anti-mite components, aromatic components, deodorizing components, etc. Specific examples of repellent components include wood tar, habanero, wood vinegar, garlic, neem, mugwort, Houttuynia cordata, green tea, stem tea, Japanese kumazasa, Korean ginseng leaves, Japanese pepper leaves, cypress, iris leaves, loquat leaves, shell ginger, chili pepper, wasabi, rosemary, limonene, pinene, terpinene, linalool, terpineol, cinnamaldehyde, azadilactin, allyl isocyanate, actylated glyceride, naphthalene, transfluthrin, metofluthrin, etc. Specific examples of aromatic components include rose oil, jasmine oil, neroli oil, lavender oil, ylang-ylang oil, chevelose oil, clary sage oil, clove oil, peppermint oil, geranium oil, patchouli oil, sandalwood oil, cinnamon oil, coriander oil, nutmeg oil, pepper oil, lemon oil, orange oil, bergamot oil, opoponax oil, vetiver oil, orris oil, oakmoss oil, musk oil, civet oil, castoreum oil, ambergris oil, limonene, β- Examples of volatile components include natural fragrances such as caryophyllene, cis-3-hexenol, linalool, farnesol, β-phenylethyl alcohol, 2,6-nonadienal, citral, α-hexyl cinnamic aldehyde, β-ionone, l-carvone, cyclopentadecanone, linalyl acetate, benzyl benzoate, γ-undecalactone, eugenol, rose oxide, indole, phenylacetaldehyde dimethyl acetal, and aurantiol. These volatile components may be used alone or in combination of two or more.

[0031] The volatile component is preferably a repellent component, and more preferably a repellent component such as wood tar, habanero, wood vinegar, garlic, neem, mugwort, Houttuynia cordata, green tea, stem tea, Japanese kumazasa, ginseng leaves, Japanese pepper leaves, cypress, iris leaves, loquat leaves, shell ginger, chili pepper, wasabi, rosemary, limonene, etc. By containing a repellent component as a volatile component, the vulcanized rubber molding can be used as a repellent that is excellent in the sustained release of the repellent component and in the durability of the repellent effect.

[0032] Tetrakis(2-ethylhexyl)thiuram disulfide (D) The rubber composition contains tetrakis(2-ethylhexyl)thiuram disulfide (TOT) as a vulcanization accelerator. By using TOT as a vulcanization accelerator, it is possible to ensure an appropriate level of sustained release of volatile components in the vulcanized rubber molded product.

[0033] <Mixture (E) of 80% by mass of dicyclohexylamine salt of ethylene glycol and 20% by mass of long-chain alkyl alcohol> The rubber composition contains a vulcanization activator consisting of a mixture of 80% by mass of dicyclohexylamine salt of ethylene glycol and 20% by mass of a long-chain alkyl alcohol. While not intended to be limiting, a commercially available product can be used as this mixture. The inclusion of the vulcanization activator accelerates the crosslinking reaction during the vulcanization molding process described below, thereby enabling vulcanization at low temperatures.

[0034] Filler (F) The rubber composition may contain optional fillers such as silica, carbon black, etc. as needed. The inclusion of fillers improves the strength and durability of the rubber vulcanizate molded article.

[0035] Additives (G) The rubber composition may further contain other additives commonly used in rubber compositions, such as zinc oxide, stearic acid, or vulcanization accelerators other than TOT, such as polyethylene glycol (PEG). The rubber vulcanizate molded article of the present disclosure, obtained by vulcanizing and molding the rubber composition of the present disclosure, can be used in a variety of locations, including indoors, warehouses, facilities, railroad freight, ships, as well as around houses, roads, and railroad tracks, outdoors (including underwater), and in the mountains. Therefore, it may contain additives such as antioxidants, flame retardants, and ozone-resistant agents as needed. The specifications and content of the additives are not particularly limited and can be within commonly used conditions. Specifically, for example, the content may be 10 parts by mass or less per 100 parts by mass of rubber polymer. These additives may be added singly or in combination.

[0036] <<Rubber composition compounding>> The rubber composition according to this embodiment contains the above components (A) to (E) in the following amounts.

[0037] Rubber polymer (A): 100 parts by mass Crosslinking agent (B): 0.3 to 5 parts by mass, preferably 0.4 to 4 parts by mass, more preferably 0.5 to 3 parts by mass in terms of sulfur Volatile component-containing agent (C): 20 to 70 parts by mass, preferably 25 to 65 parts by mass, more preferably 30 to 60 parts by mass in terms of volatile components Tetrakis(2-ethylhexyl)thiuram disulfide (D): 0.5 to 3 parts by mass, preferably 1 to 2.5 parts by mass, more preferably 1.5 to 2 parts by mass A mixture of 80% by mass of dicyclohexylamine salt of ethylene glycol and 20% by mass of long-chain alkyl alcohol (E): 0.5 to 4 parts by mass, preferably 0.5 to 3 parts by mass, more preferably 0.5 to 2.5 parts by mass, and even more preferably 1 to 2 parts by mass With the above-mentioned constitution, a vulcanized rubber molded article obtained by molding and curing the rubber composition has excellent sustained release properties of volatile components, and therefore the effects of the volatile components are maintained for an extended period of time.

[0038] If the amount of crosslinking agent (B) is less than the lower limit, the crosslinking reaction may not proceed sufficiently, whereas if the amount of crosslinking agent (B) is more than the upper limit, the crosslinking reaction may proceed too much, resulting in insufficient physical properties of the rubber vulcanized molded article.

[0039] If the amount of the volatile component-containing agent (C) is less than the lower limit, the effect of the volatile component may not be sufficient, whereas if the amount of the volatile component-containing agent (C) is more than the upper limit, the dispersibility of the volatile component-containing agent (C) in the rubber polymer (A) may be insufficient.

[0040] Furthermore, if the blending amounts of components (D) and (E) are outside the above ranges, low-temperature vulcanization in the vulcanization molding step S2 described below may become difficult. That is, by setting the contents of components (D) and (E) within the above ranges, vulcanization at low temperatures and in a short time becomes possible, as shown in the vulcanization reactivity evaluation test described below (see FIG. 5), and evaporation of volatile components in the vulcanization molding step S2 can be effectively suppressed.

[0041] The rubber composition according to the present embodiment may contain the filler (F), preferably silica, in an amount of preferably 15 to 25 parts by mass, more preferably 17 to 23 parts by mass, per 100 parts by mass of the rubber polymer (A).

[0042] Before the kneading step S1, i.e., in the weighed rubber composition, the content of volatile components is preferably 15% by mass or more and 40% by mass or less, more preferably 18% by mass or more and 35% by mass or less, and even more preferably 18% by mass or more and 32% by mass or less.

[0043] This makes it possible to provide a vulcanized rubber molded article that is excellent in the effect of the volatile components and that effect lasts.

[0044] <Method of manufacturing vulcanized rubber molded body> The vulcanized rubber molded article according to the present disclosure can be obtained by vulcanizing and molding the above-described rubber composition.

[0045] Specifically, as shown in FIG. 1, the method for producing a vulcanized rubber molded article according to the present disclosure includes a kneading step S1 and a vulcanization molding step S2.

[0046] <Kneading process> As shown in FIGS. 1 and 2, the kneading step S1 includes a first kneading step S11 and a second kneading step S12.

[0047] [First kneading process] In the first kneading step S11, the rubber polymer (A) and, if necessary, a portion of the optional additive (G) (e.g., zinc oxide) are first charged into a kneading machine such as a mixer, kneader, or roll, and kneaded for a predetermined time (e.g., 1 to 10 minutes) at a low rotation speed (e.g., 10 rpm) to a maximum rotation speed (which may be varied depending on the specifications of the kneading machine, specifically, 40 to 50 rpm). During this time, the temperature of the kneaded product reaches approximately 100°C. In this way, a kneaded product in a relatively soft state is obtained.

[0048] Next, the volatile component-containing agent (C) and, if necessary, the optional filler (F) and the remainder of the additives (G) (e.g., stearic acid and PEG) are added to the kneaded mixture, and the mixture is kneaded for a predetermined time (e.g., about 1 minute) at a low rotation speed of, for example, about 10 to 25 rpm. After cleaning, the mixture is kneaded again for a predetermined time (e.g., about 1 minute) at a low rotation speed of, for example, about 25 rpm. By suppressing the rotation speed in this way, the temperature of the kneaded mixture after adding the volatile component-containing agent (C) is maintained at 100°C or below, and evaporation of the volatile components is suppressed.

[0049] If the volatile component-containing agent (C) is liquid, it may not be uniformly dispersed in the kneaded product and may separate, for example, by adhering to the wall of the kneading tank. In such cases, the dispersibility in the kneaded product can be improved by adding the volatile component-containing agent (C) to the compound simultaneously with the filler (F) and additives (G).

[0050] The resulting kneaded product is formed into a sheet by sheeting and cooled.

[0051] [Second kneading process] In the second kneading step S12, the crosslinking agent (B), TOT (D), and vulcanization activator (E) are added to the sheet-like kneaded product obtained in the first kneading step S11, and kneading is performed for a predetermined time (for example, about 1 minute) at a low rotation speed of, for example, about 20 rpm. Then, after cleaning, kneading is performed again for a predetermined time (for example, about 1 minute) at a low rotation speed of, for example, about 20 rpm. By suppressing the rotation speed in this way, the temperature of the kneaded product is maintained at 80°C or less, and evaporation of volatile components is suppressed.

[0052] The resulting kneaded product is formed into a sheet by sheeting and cooled, thereby obtaining a sheet-like rubber composition.

[0053] In this way, by maintaining the temperature of the kneaded material after adding the volatile component-containing agent (C) in the kneading step S1 at 100°C or less, preferably at 100°C or less in the first kneading step S11 and at 80°C or less in the second kneading step S12, the evaporation of the volatile components in the kneading step S1 can be suppressed.

[0054] <Vulcanization molding process> In the vulcanization molding step S2, the sheet-shaped rubber composition obtained in the kneading step S1 is vulcanized to obtain a vulcanized rubber molded article.

[0055] The vulcanization molding method is not particularly limited, and generally known methods can be used, specifically, for example, a method in which the product is preformed into a desired shape by extrusion molding, press molding, injection molding, roll processing, or the like, and heated simultaneously with molding, or a method in which the molded product is introduced into a crosslinking tank and heated can be used.

[0056] In the method for producing a vulcanized rubber molded product according to the present disclosure, in the vulcanization molding step S2, the vulcanization temperature is preferably 140°C or lower, more preferably 100°C or higher but lower than 138°C, even more preferably 120°C or higher but lower than 135°C, and particularly preferably 125°C or higher but lower than 134°C. The vulcanization time is preferably 30 minutes or shorter, more preferably 1 minute or higher but lower than 20 minutes, and particularly preferably 5 minutes or higher but lower than 15 minutes. This allows the crosslinking reaction to be sufficiently promoted while suppressing the evaporation of volatile components.

[0057] In the method for producing a vulcanized rubber molded article according to the present disclosure, the temperature of the kneaded material in at least the kneading step S1 is adjusted as described above. In addition to the kneading step S1, it is preferable to adjust the temperature in the vulcanization molding step S2 as well.

[0058] <Rubber vulcanization molding> The rubber vulcanization molded article according to the present disclosure contains volatile components dispersed in the rubber polymer, and therefore has excellent sustained release properties for the volatile components, and excellent durability of the effects of the volatile components.

[0059] The use of the vulcanized rubber molded article is not particularly limited and is appropriately determined depending on the effect of the volatile components contained therein. Specifically, for example, when the vulcanized rubber molded article contains a repellent component, an insect repellent component, an anti-mite component, a fragrance component, a deodorizing component, or the like as a volatile component, it can be used as a repellent, an insect repellent, an anti-mite component, a fragrance component, a deodorizing agent, or the like, each of which has excellent durability of effect.

[0060] The installation location of the rubber vulcanization molded article is not particularly limited. The rubber vulcanization molded article is placed and used in a desired installation location depending on the effect of the volatile component. Specifically, when the volatile component is a repellent component, an insect repellent component, an anti-mite component, or the like, it is used, for example, indoors in a home or facility, particularly in the attic or under the floor, outdoors in a home or facility, inside a railway freight train or ship, around roads or railroad tracks, outdoors including underwater, in the mountains, etc. Furthermore, when the volatile component is a fragrance component, a deodorizing component, or the like, it is used, for example, indoors in a home or facility, etc.

[0061] 3 and 4 show examples of a rubber vulcanization molded body 10 according to the present disclosure. The shape of the rubber vulcanization molded body 10 is not particularly limited, but from the viewpoint of improving handleability, it may be, for example, a polygonal body as shown in Fig. 3 or a spherical body as shown in Fig. 4. As shown in Fig. 3, the rubber vulcanization molded body 10 has a polygonal shape, which improves handleability, makes it easy to place in a fixed position, and is less likely to roll, so that its effectiveness can be maintained in a desired installation location.

[0062] The size of the rubber vulcanization molded article 10 is not particularly limited and is determined appropriately depending on the application, etc. When the rubber vulcanization molded article 10 according to the present disclosure has the shape shown in Fig. 3 and Fig. 4, the maximum diameter can be, for example, about 1 to 15 cm from the viewpoint of improving handleability, although this is not intended to be limiting.

[0063] 3 and 4, the rubber vulcanization molded product 10 preferably has a flat portion 11 on its surface. By having the flat portion 11, the flat portion can be easily placed while maintaining a constant posture when in contact with the ground or the like, and is less likely to roll, so that the effect can be maintained continuously in the desired installation location.

[0064] The rubber vulcanization molding 10 preferably has a through-hole 13 that penetrates the rubber vulcanization molding 10 in its thickness direction. By threading a string-like object such as a rope through the through-hole 13, when the effect of the volatile components of the rubber vulcanization molding 10 is lost and recovery becomes necessary, the rubber vulcanization molding 10 can be recovered by pulling the string-like object. This makes recovery easy, especially when the rubber vulcanization molding 10 is installed in a location that is difficult to access, such as an attic. The rubber vulcanization molding 10 can also be used by suspending it in a desired location using the string-like object.

[0065] As an indicator of the duration of effect, the number of days required to reduce the volatile components by 1 g (1% by mass) out of 100 g of volatile components contained in a rubber vulcanized molded product can be used, i.e., the number of days required to reduce the volatile components by 1% by mass. This number of days is preferably 15 days or more, more preferably 17 days or more, and even more preferably 20 days or more. Furthermore, the number of days required to reduce the volatile components by 1% by mass is preferably 1.4 times or more, and preferably 2 times or more, the number of days required for the volatile components alone. This indicates that the sustained release of the volatile components is sufficiently excellent, and that the effects of the volatile components are sufficiently long-lasting.

[0066] Furthermore, since the rubber vulcanized molding 10 according to the present disclosure has the above-mentioned effects, it can contribute, for example, to the achievement of Goal 9 "Build resilient infrastructure, promote inclusive and sustainable industrialization," and Goal 11 "Make sustainable cities and communities sustainable," among the 17 Sustainable Development Goals (SDGs) advocated by the United Nations.

[0067] <Experimental Example> Next, specific experimental examples will be described.

[0068] 1 and 2 and the manufacturing method described above, rubber vulcanization molded body samples of Experimental Examples 1 to 13 were manufactured. The formulations are shown in Table 1. The vulcanization conditions in the vulcanization molding step S2 were a vulcanization temperature and a vulcanization time of 10 minutes shown in Table 2 of the vulcanization reactivity evaluation test described later for Experimental Examples 1 to 6, and a vulcanization temperature of 133°C and a vulcanization time of 10 minutes for Experimental Examples 7 to 13.

[0069] [Table 1]

[0070] ≪Raw materials≫ [Rubber polymer (A)] (A-1)NR (RSS No. 3, NR content: 100% by mass) [Crosslinking agent (B)] (B-1) Finely divided sulfur 325 mesh (B-2) TMTD (Suncerer (registered trademark) TT-G, manufactured by Sanshin Chemical Industry Co., Ltd.) (B-3) DPTT (Suncerer (registered trademark) TRA, manufactured by Sanshin Chemical Industry Co., Ltd.) (B-4) DTDM (Valnoc® manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) In Table 1, the blending amounts of the crosslinking agents (B-2) to (B-4) are shown in terms of sulfur amount.

[0071] [Volatile component-containing agent (C)] (C-1) Futawa Corporation, Repellent Ichiban (registered trademark), liquid type (content of repellent component as volatile component: 100% by mass) (C-2) Attic Pest Niger, individual packets, manufactured by Afti Co., Ltd. (C-3) Futawa Corporation, Repellent No. 1 (registered trademark), solid type In Table 1, the blending amount of the volatile component-containing agent (C-2) is shown in terms of volatile components.

[0072] [TOT(D)] (D-1) TOT (thiram-based vulcanization accelerator, Noccela (registered trademark) TOT-N, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) [Vulcanization activator (E)] (E-1) Vulcanization activator (Knockmaster (registered trademark) EGS manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) Filler (F-1) Silica (Tokusil (registered trademark) UR manufactured by Maruo Calcium Co., Ltd.) [Additive (G)] (G-1) Two types of zinc oxide (G-2) Stearic acid (NOF Corporation, Beads, Stearic Acid, Camellia) (G-3) PEG (polyethylene glycol, Fujifilm Wako Pure Chemical Industries, Ltd. PEG 4000) <Volatility evaluation test> 100 g of the volatile component-containing agent (C-1) was placed in a beaker and heated at a predetermined temperature (60°C to 160°C (in 10°C increments)) for 10 minutes. The mass was measured before and after heating, and the amount of volatilization at each temperature was calculated from the difference in mass. The results are shown in Figure 5.

[0073] As shown in Figure 5, the amount of evaporation is 4 g or less at temperatures below 140°C, and 1 g or less at temperatures below 100°C. This shows that the evaporation of volatile components is suppressed by controlling the temperatures within the above-mentioned ranges in the kneading step S1 and the vulcanization molding step S2.

[0074] <Vulcanization reactivity evaluation test> The rubber compositions of Experimental Examples 1 to 6 were subjected to a vulcanization test in accordance with JIS K 6300-2, and their respective vulcanization curves were obtained (Experimental Example 1 was at a vulcanization temperature of 130°C to 170°C, and Experimental Examples 2 to 6 were at a vulcanization temperature range of 100°C to 170°C, with increments of 10°C). From each vulcanization curve, the t c (90) (90% vulcanization time, also simply referred to as "vulcanization time" in this specification) was calculated.

[0075] 6 is a graph showing the relationship between the vulcanization temperature and the vulcanization time for the rubber compositions of Experimental Examples 1 to 6. Table 2 shows the vulcanization temperature calculated based on the results of FIG.

[0076] [Table 2]

[0077] As shown in Table 2, the vulcanization temperatures for 10 minutes in Experimental Examples 3 to 6 were 140°C or lower, which was lower than the vulcanization temperatures in Experimental Examples 1 and 2. This enabled vulcanization at a low temperature in a short time (10 minutes), and it was found that the evaporation of volatile components in the vulcanization molding step S2 could be suppressed. In particular, the vulcanization temperatures in Experimental Examples 4 and 5 were low, at 133°C to 135°C, which was found to effectively suppress the evaporation of volatile components in the vulcanization molding step S2.

[0078] <Effective Durability Evaluation Test 1> The effect duration of the sample of Experimental Example 4 and the volatile component-containing agent (C-1) was evaluated. Specifically, 100 g of the sample of Experimental Example 4 (sample shape: cylindrical, 29 mm diameter x 12.5 mm thickness, number of samples: 10) and 100 g of the volatile component-containing agent (C-1) were prepared and placed in a resin container (bottle-shaped, with an opening diameter of 50 mm and a height of 190 mm). Each container was left in an exposure environment (indoors, without temperature control (fluctuating between approximately 10 and 20°C)) for a predetermined period, and the change in mass of the sample and the volatile component-containing agent (C-1) in the bottle was measured over time. The results are shown in Figure 7. Note that the data indicated by the solid line in Figure 7 represents the change in mass of the sample of Experimental Example 4 over time converted to a volatile component basis, i.e., the change in mass of the volatile component over time when the mass of the volatile component contained in the sample of Experimental Example 4 is converted to 100 g. The data is the average value of data obtained from 10 samples.

[0079] 7, the number of days required for the sample of Experimental Example 4 and the volatile component-containing agent (C-1) to lose 1% by mass of volatile components was calculated. The results are shown in Table 3.

[0080] [Table 3]

[0081] As shown in Table 3, the number of days required for a 1% by mass reduction in volatile components was 12 days for the volatile component-containing agent (C-1), while it was 28 days for the sample of Experimental Example 4. This demonstrates that, compared to commercially available repellents, the rubber vulcanized molded article of the present disclosure improves the sustained release of the repellent component as a volatile component, and improves the duration of the effect of the repellent component by approximately 2.3 times.

[0082] <Effective Durability Evaluation Test 2> 100 g of the sample of Experimental Example 7 (sample shape: cylindrical, 29 mm diameter x 12.5 mm thickness, number of samples: 10) and 100 g of the volatile component-containing agent (C-2) were prepared and placed in a resin container (bottle-shaped, with an opening diameter of 50 mm and a height of 190 mm). Each container was left in an exposure environment (indoors, without temperature control (fluctuating between approximately 10 and 20°C)) for a predetermined period of time, and the change in mass of the sample and the volatile component-containing agent (C-2) in the bottle was measured over time. This change over time (using the average value of data obtained for 10 samples) was converted into a volatile component-based value. The results are shown in Figure 8. From the results in Figure 8, the number of days required to reduce the volatile component by 1% by mass was calculated for each of the sample of Experimental Example 7 and the volatile component-containing agent (C-2). The results are shown in Table 3 above.

[0083] As shown in Table 3, the number of days required for a 1% by mass reduction in volatile components was 2 days for the volatile component-containing agent (C-2), while it was 86 days for the sample of Experimental Example 7. This shows that, compared to commercially available repellents, the rubber vulcanized molded article of the present disclosure improves the sustained release of the repellent component as a volatile component, and improves the duration of the effect of the repellent component by approximately 43 times.

[0084] <Effective Durability Evaluation Test 3> 100 g of samples from Experimental Examples 8 to 12 (sample shape: cylindrical, 29 mm diameter x 12.5 mm thickness; number of samples: 10 for each Experimental Example) were placed in a resin container (bottle-shaped, with an opening of 50 mm diameter and 190 mm height). Each container was left in an exposure environment (indoors, without temperature control (approximately 10 to 20°C)) for a predetermined period of time, and the change in mass of the sample including the bottle was measured over time. This change over time was converted into a volatile component basis (the average value of data obtained for 10 samples for each Experimental Example was used). The results are shown in Figures 9 and 10. Note that Figure 9 also shows the results of Experimental Example 4 of the aforementioned Effect Durability Evaluation Test 1. The samples of Experimental Examples 4, 8, and 9 differed only in the amount of crosslinking agent (B-1) blended. Furthermore, Experimental Examples 9, 10 to 12 differed only in the type of crosslinking agent (B). 9 and 10, the number of days required for a 1% by mass reduction in volatile components was calculated for each of the samples of Experimental Examples 8 to 12. The results are shown in Table 3 above.

[0085] As shown in Table 3, it was found that the number of days required to reduce the volatile components by 1% by mass exceeded 15 days for all of the samples of Examples 8 to 12. This demonstrates that the rubber vulcanized molded article of the present disclosure is excellent in the sustained release of the repellent component as a volatile component and in the sustained effect of the repellent component.

[0086] <Stain resistance evaluation test 1> The sample of Experimental Example 13 and the volatile component-containing agent (C-3) were placed on white paper and left for one or four weeks under indoor atmospheric conditions (temperature 23°C or 40°C, humidity 40%). After one or four weeks, the sample and the volatile component-containing agent (C-3) were removed, and the surface of the white paper was visually observed. A photograph of the surface is shown in Figure 11.

[0087] With the volatile component-containing agent (C-3), significant discoloration was observed on the white paper under all conditions. It is believed that color transfer occurred due to the evaporation of the repellent component as a volatile component, contaminating the white paper. On the other hand, with the sample of Experimental Example 13, only a slight coloring was observed on the surface of the white paper, and almost no staining was observed. These results demonstrate that the rubber vulcanized molded product of the present disclosure has reduced color transfer and improved stain resistance compared to commercially available repellents.

[0088] <Stain resistance evaluation test 2> The sample of Experimental Example 13 was placed on four types of substrates (thick white paper, paulownia wood board, MDF board, and plywood board) and left for one week under indoor atmospheric conditions (temperature of 50°C or 70°C, humidity of 40%). After one week, the sample was removed and the surfaces of the substrates were visually observed. At all temperatures, slight coloring was observed on the surface of the thick white paper, while no coloring was observed on the surfaces of the other three types of substrates. These results demonstrate that the rubber vulcanized molded product of the present disclosure exhibits excellent stain resistance and inhibits color transfer even under harsh conditions of temperatures of 50°C or 70°C.

[0089] (Variation) <Rubber vulcanization molding> Modified examples of the rubber vulcanization molded article 10 according to the present disclosure will be described below. In the description of these modified examples, the same components as those described above will be assigned the same reference numerals, and detailed description thereof will be omitted.

[0090] Other examples of the vulcanized rubber molded article 10 according to the present disclosure (hereinafter also referred to as "the article") are shown in Figures 12 to 35. These vulcanized rubber molded articles 10 have flat portions 11 and through-holes 13.

[0091] This product is a controlled release device for chemicals made of a rubber molded body into which volatile chemicals (volatile components) such as repellents, insect repellents, anti-mite agents, fragrances, and deodorizers have been kneaded, and it slowly releases the kneaded chemicals to the outside. This product is used by placing it in a desired location indoors or outdoors depending on the function of the chemicals. This product has a through-hole that passes vertically through the product, and can also be used by passing a string-like object such as a rope for recovery or hanging through the through-hole.

[0092] Fig. 12 is a perspective view showing another example of a rubber vulcanization molded body according to the present disclosure. Fig. 13 is a front view of the rubber vulcanization molded body of Fig. 12. The back view of the rubber vulcanization molded body is the same as the front view. Fig. 14 is a left side view of the rubber vulcanization molded body of Fig. 12. The right side view of the rubber vulcanization molded body is the same as the left side view. Fig. 15 is a plan view of the rubber vulcanization molded body of Fig. 12. The bottom view of the rubber vulcanization molded body is the same as the plan view. The thin lines in the perspective views, front views, left side views and plan views shown in Figs. 12 to 15 represent the shape of the three-dimensional surface.

[0093] Fig. 16 is a perspective view showing another example of a rubber vulcanization molded article according to the present disclosure. Fig. 17 is a front view of the rubber vulcanization molded article of Fig. 16. The back view of the rubber vulcanization molded article is the same as the front view. Fig. 18 is a left side view of the rubber vulcanization molded article of Fig. 16. The right side view of the rubber vulcanization molded article is the same as the left side view. Fig. 19 is a plan view of the rubber vulcanization molded article of Fig. 16. The bottom view of the rubber vulcanization molded article is the same as the plan view. The thin lines in the perspective views, front views, left side views and plan views shown in Figs. 16 to 19 represent the shape of the three-dimensional surface.

[0094] Fig. 20 is a perspective view showing another example of a rubber vulcanization molded body according to the present disclosure. Fig. 21 is a front view of the rubber vulcanization molded body of Fig. 20. The back view of the rubber vulcanization molded body is the same as the front view. Fig. 22 is a left side view of the rubber vulcanization molded body of Fig. 20. The right side view of the rubber vulcanization molded body is the same as the left side view. Fig. 23 is a plan view of the rubber vulcanization molded body of Fig. 20. The bottom view of the rubber vulcanization molded body is the same as the plan view. The thin lines in the perspective views, front views, left side views and plan views shown in Figs. 20 to 23 represent the shape of the three-dimensional surface.

[0095] Fig. 24 is a perspective view showing another example of a rubber vulcanization molded body according to the present disclosure. Fig. 25 is a front view of the rubber vulcanization molded body of Fig. 24. The back view of the rubber vulcanization molded body is the same as the front view. Fig. 26 is a left side view of the rubber vulcanization molded body of Fig. 24. The right side view of the rubber vulcanization molded body is the same as the left side view. Fig. 27 is a plan view of the rubber vulcanization molded body of Fig. 24. The bottom view of the rubber vulcanization molded body is the same as the plan view. The thin lines in the perspective views, front views, left side views and plan views shown in Figs. 24 to 27 represent the shape of the three-dimensional surface.

[0096] Fig. 28 is a perspective view showing another example of a rubber vulcanization molded body according to the present disclosure. Fig. 29 is a front view of the rubber vulcanization molded body of Fig. 28. The back view of the rubber vulcanization molded body is the same as the front view. Fig. 30 is a left side view of the rubber vulcanization molded body of Fig. 28. The right side view of the rubber vulcanization molded body is the same as the left side view. Fig. 31 is a plan view of the rubber vulcanization molded body of Fig. 28. The bottom view of the rubber vulcanization molded body is the same as the plan view. The thin lines in the perspective views, front views, left side views and plan views shown in Figs. 28 to 31 represent the shape of the three-dimensional surface.

[0097] Fig. 32 is a perspective view showing another example of a rubber vulcanization molded body according to the present disclosure. Fig. 33 is a front view of the rubber vulcanization molded body of Fig. 32. The back view of the rubber vulcanization molded body is the same as the front view. Fig. 34 is a left side view of the rubber vulcanization molded body of Fig. 32. The right side view of the rubber vulcanization molded body is the same as the left side view. Fig. 35 is a plan view of the rubber vulcanization molded body of Fig. 32. The bottom view of the rubber vulcanization molded body is the same as the plan view. The thin lines in the perspective views, front views, left side views and plan views shown in Figs. 32 to 35 represent the shape of the three-dimensional surface. [Explanation of symbols]

[0098] 10. Rubber vulcanization molding 11 Flat area 13 Through hole

Claims

1. Rubber polymer (A) mainly composed of natural rubber: 100 parts by mass; Crosslinking agent (B): 0.3 to 5 parts by mass in terms of sulfur, Volatile component-containing agent (C): 20 to 70 parts by mass in terms of volatile components, Tetrakis(2-ethylhexyl)thiuram disulfide (D): 0.5 to 3 parts by mass, and 0.5 to 4 parts by mass of a mixture (E) of 80% by mass of dicyclohexylamine salt of ethylene glycol and 20% by mass of a long-chain alkyl alcohol. A rubber composition characterized by:

2. In claim 1, The volatile component of the volatile component-containing agent (C) is a repellent component. A rubber composition characterized by:

3. In claim 1, In the rubber composition, the content of the volatile component of the volatile component-containing agent (C) is 15% by mass or more and 40% by mass or less. A rubber composition characterized by:

4. In claim 1, Further, it contains 15 to 25 parts by mass of a filler (F). A rubber composition characterized by:

5. A vulcanized rubber molded article comprising the rubber composition according to any one of claims 1 to 4.

6. In claim 5, The number of days required to reduce the volatile components by 1% by mass is 15 days or more. A rubber vulcanization molded article characterized by the above.

7. A method for producing a vulcanized rubber molded product, comprising: a kneading step of obtaining a rubber composition by kneading at least 100 parts by mass of a rubber polymer (A) mainly composed of natural rubber, 0.3 to 5 parts by mass of a crosslinking agent (B) in terms of sulfur, 20 to 70 parts by mass of a volatile component-containing agent (C) in terms of volatile components, 0.5 to 3 parts by mass of tetrakis(2-ethylhexyl)thiuram disulfide (D), and 0.5 to 4 parts by mass of a mixture (E) of 80% by mass of a dicyclohexylamine salt of ethylene glycol and 20% by mass of a long-chain alkyl alcohol; a vulcanization molding step of vulcanizing the rubber composition to obtain the vulcanized rubber molded article, the temperature of the kneaded mixture after adding the volatile component-containing agent (C) in the kneading step is 100°C or less; The vulcanization temperature in the vulcanization molding step is 140°C or less. A method for producing a vulcanized rubber molded article, comprising:

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