Cross-linking agent for chlorinated butyl rubber

Abstract

Provided is a cross-linking agent for chlorinated butyl rubber, which has a high cross-linking reaction speed and excellent rubber elasticity. When a primary aminotriazine dithiol compound represented by the following chemical formula (1) is used as a cross-linking agent in a chlorinated butyl rubber composition, it is possible to increase the cross-linking reaction speed and obtain a cross-linked rubber having excellent rubber elasticity. # imgabs0 # (wherein R1 represents a linear or branched hydrocarbon group having 6 to 10 carbon atoms); )

Description

Technical Field

[0001] The present invention relates to a crosslinking agent for chlorinated butyl rubber, and more particularly to a crosslinking agent suitable for use in the manufacture of medical rubber products composed of chlorinated butyl rubber compositions. Background Art

[0002] Halogenated butyl rubber is a rubber material used for pipes, packaging materials, sealing materials, and the like, which has excellent impermeability to the three states of matter (gas, liquid, and solid).

[0003] In addition, such characteristics are also suitable as a material for medical rubber products such as rubber stoppers for vials or gaskets for syringes.

[0004] Halogenated butyl rubber can be classified into chlorobutyl rubber and bromobutyl rubber, which differ in some characteristics.

[0005] For example, brominated butyl rubber (hereinafter referred to as BIIR) has high cross-linking reactivity and can be cross-linked in a short time, so it is more advantageous than chlorobutyl rubber (hereinafter referred to as CIIR) in terms of productivity. However, additives such as epoxidized soybean oil are added as stabilizers, and the solubility of the additives in water (hereinafter referred to as "solubility in water") sometimes becomes a problem.

[0006] On the other hand, CIIR is inferior to BIIR in productivity, but does not require the addition of a stabilizer and is therefore more advantageous than BIIR in terms of the dissolution of additives.

[0007] In addition, there are several crosslinking methods for crosslinking halogenated butyl rubber, and according to the type of crosslinking agent, for example, sulfur crosslinking, peroxide crosslinking, metal oxide crosslinking, resin crosslinking, amine crosslinking and thiol crosslinking can be listed. In medical use, since it is necessary to ensure the safety to the organism, the solubility of the above crosslinking agent is emphasized, so thiol crosslinking with low solubility is often used. Here, the above crosslinking agent is also included in one of the additives in the halogenated butyl rubber.

[0008] As a specific crosslinking agent in thiol crosslinking, an aminotriazine dithiol compound is used, and in particular, 6-(di-n-butylamino)-1,3,5-triazine-2,4-dithiol (hereinafter referred to as "BSH") is commercially available and generally used (Patent Document 1).

[0009] Based on the above, in conventional medical rubber products such as rubber stoppers and gasket materials, CIIR is selected, and BSH is used as its crosslinking agent, especially for products that require low dissolution.

[0010] However, this combination of CIIR and BSH additive has low solubility and is extremely excellent, but has low productivity due to its slow cross-linking reaction rate, and therefore a cross-linking agent with a faster cross-linking reaction rate is required.

[0011] Furthermore, in response to the recent strong demand for medical rubber products, it is necessary to meet this demand while ensuring safety to living bodies, and thus a cross-linking agent with low solubility of additives and a faster cross-linking reaction rate is required.

[0012] Prior to the present invention, there was 6-[bis(2-ethylhexyl)amino]-1,3,5-triazine-2,4-dithiol (Patent Document 2), which is an aminotriazine dithiol compound that can make the cross-linking reaction rate faster than BSH. However, the molecular weight of 6-[bis(2-ethylhexyl)amino]-1,3,5-triazine-2,4-dithiol is higher than that of BSH, and in order to obtain the rubber elasticity required for rubber stoppers or gasket materials, the amount of addition must be increased.

[0013] An increase in the amount of cross-linking agent added becomes a factor that increases the manufacturing cost of rubber stoppers or gaskets as products, and therefore a new cross-linking agent is needed that can accelerate the cross-linking reaction rate at an addition amount that is approximately equal to or less than that of BSH, and further, can provide rubber products after the cross-linking reaction with rubber elasticity that is equal to or higher than that of the case where BSH is used.

[0014] Prior art literature

[0015] Patent Literature

[0016] Patent Document 1: Japanese Patent Application Publication No. 2002-301133

[0017] Patent Document 2: Japanese Patent Application Publication No. 2014-237797 Summary of the invention

[0018] Problems to be solved by the present invention

[0019] The present inventors have conducted intensive studies to solve the above problems and have completed the present invention. That is, by using an aminotriazine dithiol compound represented by the following chemical formula (1) as a crosslinking agent, the crosslinking reaction rate of the chlorinated butyl rubber composition can be accelerated while imparting high rubber elasticity.

[0020] [Chemical formula 1]

[0021]

[0022] (Among them, R 1 It represents a straight-chain or branched hydrocarbon group having 6 to 10 carbon atoms.

[0023] Therefore, in view of the above circumstances, the present invention provides a cross-linking agent for chlorinated butyl rubber having a fast cross-linking reaction rate and excellent rubber elasticity.

[0024] Means used to solve problems

[0025] The present invention provides a cross-linking agent for chlorinated butyl rubber represented by the following chemical formula (1).

[0026] [Chemical formula 2]

[0027]

[0028] (Among them, R 1 It represents a straight-chain or branched hydrocarbon group having 6 to 10 carbon atoms.

[0029] The rubber composition preferably contains 0.01 to 10 parts by weight of the compound represented by the chemical formula (1) based on 100 parts by weight of the chlorinated butyl rubber.

[0030] Preferred are rubber products obtained by crosslinking the above-mentioned rubber compositions.

[0031] A medical rubber composition composed of the above-mentioned rubber composition is preferred.

[0032] Preferred is a medical rubber product obtained by crosslinking the above-mentioned medical rubber composition.

[0033] Effects of the Invention

[0034] According to the present invention, when the aminotriazine dithiol compound represented by the above chemical formula (1) is used as a crosslinking agent for a chlorinated butyl rubber composition, the productivity of a medical rubber product having high elasticity and low elution of additives can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] [ Figure 1 ] shows the relationship between the vulcanization time and rubber elasticity of each embodiment and each comparative example. DETAILED DESCRIPTION

[0036] Specific embodiments of the present invention will be described below.

[0037] The rubber component used as the base in the present invention is chlorinated butyl rubber (CIIR), which can be used alone or mixed with other rubber components such as brominated butyl rubber (BIIR), synthetic polyisoprene rubber (IR), styrene butadiene copolymer rubber (SBR), acrylonitrile butadiene rubber (NBR), ethylene propylene diene copolymer rubber (EPDM), polyisobutylene rubber (IIR) for the purpose of imparting rubber properties to these components. When other rubber components are mixed, the base rubber component CIIR is used in an amount of at least 50 parts by weight, preferably 80 parts by weight, and more preferably 95 parts by weight, relative to 100 parts by weight of the total rubber components.

[0038] The crosslinking agent in the present invention is an aminotriazine dithiol compound represented by the above chemical formula (1), and is used in an amount of 0.01 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the chlorinated butyl rubber.

[0039] The aminotriazine dithiol compound represented by the above chemical formula (1) may be used alone or in combination with other crosslinking agents. When used in combination with other crosslinking agents, the aminotriazine dithiol compound represented by the above chemical formula (1) may be substituted in a range of 50% by weight or less, preferably 30% by weight or less, and more preferably 10% by weight or less, based on 100% by weight of the aminotriazine dithiol compound represented by the above chemical formula (1).

[0040] On the other hand, in the aminotriazine dithiol compound represented by the chemical formula (1), R 1 The aminotriazine dithiol compounds having a straight chain or branched hydrocarbon group whose carbon number deviates from 5 or less as in the present invention also have a crosslinking effect on CIIR, but the crosslinking reaction speed cannot be said to be sufficiently fast.

[0041] In addition, with the above R 1 An aminotriazine dithiol compound having a linear or branched hydrocarbon group with 11 or more carbon atoms also has a crosslinking effect on CIIR, but the rubber elasticity is reduced and sufficiently high rubber elasticity cannot be obtained.

[0042] Furthermore, when an aminotriazine dithiol compound to which an alicyclic or aromatic hydrocarbon group is added is used as a crosslinking agent, even if the above R 1 The number of carbon atoms is in the range of 6 to 10, and the cross-linking reaction rate cannot be said to be sufficiently fast. In addition, the rubber elasticity cannot be said to be sufficiently high.

[0043] The primary aminotriazine dithiol compound identified in the present invention not only provides a rapid crosslinking reaction rate and high rubber elasticity, but also excels in low dissolution of additives, which is important in products for medical use, and does not serve as a source of nitrosamine generation.

[0044] Furthermore, there are no particular limitations on the compounding ingredients required to obtain a medical rubber composition mainly composed of chlorinated butyl rubber. For example, even in a conventional rubber composition using BSH as a crosslinking agent, the effects of the present invention can be obtained by simply replacing BSH with the primary aminotriazine dithiol compound identified in the present invention.

[0045] Example

[0046] The present invention will be described in more detail below with reference to examples, but the present invention is of course not limited to the examples.

[0047] This is an example of synthesis of the compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol of Example 1 represented by the following chemical formula (1-1).

[0048] [Chemical formula 3]

[0049]

[0050] 90.2g (489mmol) of cyanuric chloride and 165g of toluene were added to a flask, cooled to below 5°C, and stirred. 49.6g (490mmol) of hexylamine (6 carbon atoms, straight chain) was dissolved in 165g of toluene, added dropwise at below 20°C, and stirred at the same temperature for two hours. After the stirring was completed, an aqueous sodium hydroxide solution was added to separate the liquids, and the organic layer was heated to 50°C while stirring. An aqueous sodium hydrosulfide solution was added dropwise thereto, and stirred for one hour. Then, 30wt% sulfuric acid was added dropwise to precipitate crystals. The obtained crystals were filtered, washed, and dried at 80°C to obtain 96.0g of white crystals as the target substance.

[0051] The analysis results for the structural identification of the compound are shown.

[0052] 1 H-NMR (Solvent: DMSO-d6)

[0053] 0.86(t,J=6.8Hz,3H),1.26-1.28(m,6H),1.46-1.47(m,2H),3.27-3.31(m,2H),7.11(br,1H),12.22(br,1H),12.87(s,1H)

[0054] 13 C-NMR (solvent: DMSO-d6) 13.9, 22.1, 25.8, 28.5, 30.9, 40.4, 149.8, 173.7, 182.9

[0055] This is an example of synthesis of the compound 6-(n-heptylamino)-1,3,5-triazine-2,4-dithiol of Example 2 represented by the following chemical formula (1-2).

[0056] [Chemical formula 4]

[0057]

[0058] The same procedure was followed except that 56.5 g (490 mmol) of heptylamine (7 carbon atoms, straight chain) was used instead of hexylamine (6 carbon atoms, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), and 107 g of white crystals as the target substance were obtained.

[0059] The analysis results for the structural identification of the compound are shown.

[0060] 1 H-NMR (Solvent: DMSO-d6)

[0061] 0.85(t,J=6.9Hz,3H),1.26(m,8H),1.46-1.49(m,2H),3.27-3.31(m,2H),7.11(br,1H),12.22(br,1H),12.88(s,1H)

[0062] 13 C-NMR (Solvent: DMSO-d6)

[0063] 14.2, 22.2, 26.3, 28.5, 28.7, 31.4, 40.5, 150.0, 174.0, 182.9 Synthesis example of the compound 6-(n-octylamino)-1,3,5-triazine-2,4-dithiol of Example 3 represented by the following chemical formula (1-3).

[0064] [Chemical formula 5]

[0065]

[0066] The same procedure was followed except that 63.8 g (494 mmol) of octylamine (8 carbon atoms, straight chain) was used instead of hexylamine (6 carbon atoms, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), yielding 84.5 g of white crystals as the target substance.

[0067] The analysis results for the structural identification of the compound are shown.

[0068] 1 H-NMR (Solvent: DMSO-d6)

[0069] 0.86(t,J=7.0Hz,3H),1.26(m,10H),2.04(m,2H),3.29(m,2H),7.12(br,1H),12.23(br,1H),12.90(s,1H)

[0070] 13 C-NMR (Solvent: DMSO-d6)

[0071] 14.0, 22.1, 26.1, 28.6, 28.7, 28.7, 31.3, 40.4, 149.8, 173.5, 183.1

[0072] This is an example of synthesis of the compound 6-(2-ethylhexylamino)-1,3,5-triazine-2,4-dithiol of Example 4 represented by the following chemical formula (1-4).

[0073] [Chemical formula 6]

[0074]

[0075] The same procedure was followed except that 64.3 g (497 mmol) of 2-ethylhexylamine (8 carbon atoms, branched) was used instead of hexylamine (6 carbon atoms, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), to obtain 120 g of white crystals as the target substance.

[0076] The analysis results for the structural identification of the compound are shown.

[0077] 1 H-NMR (Solvent: DMSO-d6)

[0078] 0.85(t,J=7.6Hz,3H),0.87(t,J=6.7Hz,3H),1.25-1.29(m,8H),1.51(m,1H),3.27(m,2H),7.04(br,1H),12.03(br,1H),12.90(s,1H)

[0079] 13 C-NMR (Solvent: DMSO-d6)

[0080] 10.7, 14.0, 22.5, 23.5, 28.2, 30.1, 38.3, 43.0, 150.0, 173.2, 183.2

[0081] This is an example of synthesis of the compound 6-(nonylamino)-1,3,5-triazine-2,4-dithiol of Example 5 represented by the following chemical formula (1-5).

[0082] [Chemical formula 7]

[0083]

[0084] The same procedure was followed except that 70.2 g (490 mmol) of nonylamine (9 carbon atoms, straight chain) was used instead of hexylamine (6 carbon atoms, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), to obtain 94.6 g of white crystals as the target substance.

[0085] The analysis results for the structural identification of the compound are shown.

[0086] 1 H-NMR (Solvent: DMSO-d6)

[0087] 0.85(t,J=6.9Hz,3H),1.24-1.25(m,12H),1.47-1.48(m,2H),3.27-3.31(m,2H),7.11(br,1H),12.22(br,1H),12.88(s,1H)

[0088] 13 C-NMR (Solvent: DMSO-d6)

[0089] 14.2, 22.3, 26.3, 28.7, 28.9(2C), 29.2, 31.5, 40.5, 150.0, 173.8, 183.1

[0090] This is an example of synthesis of the compound 6-(decylamino)-1,3,5-triazine-2,4-dithiol of Example 6 represented by the following chemical formula (1-6).

[0091] [Chemical formula 8]

[0092]

[0093] The same procedure was followed except that 77.1 g (490 mmol) of decylamine (10 carbon atoms, straight chain) was used instead of hexylamine (6 carbon atoms, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), to obtain 101 g of white crystals as the target substance.

[0094] The analysis results for the structural identification of the compound are shown.

[0095] 1 H-NMR (Solvent: DMSO-d6)

[0096] 0.85(t,J=7.0Hz,3H),1.25-1.26(m,14H),1.48-1.49(m,2H),3.27-3.31(m,2H),7.12(br,1H),12.24(br,1H),12.90(s,1H)

[0097] 13 C-NMR (Solvent: DMSO-d6)

[0098] 14.0, 22.2, 26.1, 28.6, 28.7, 28.8, 29.0, 29.0, 31.4, 40.3, 149.8, 173.7, 183.1

[0099] This is an example of synthesis of the compound 6-(ethylamino)-1,3,5-triazine-2,4-dithiol of Comparative Example 2 represented by the following chemical formula (2-1).

[0100] [Chemical formula 9]

[0101]

[0102] The same procedure was followed except that 22.1 g (490 mmol) of ethylamine (carbon number 2, straight chain) was used instead of hexylamine (carbon number 6, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), and 42.4 g of white crystals as the target substance were obtained.

[0103] The analysis results for the structural identification of the compound are shown.

[0104] 1 H-NMR (Solvent: DMSO-d6)

[0105] 1.09(t,J=7.2Hz,3H),3.31-3.36(m,2H),7.13(br,1H),12.36(br,1H),12.90(s,1H)

[0106] 13 C-NMR (Solvent: DMSO-d6)

[0107] 14.6, 35.7, 149.8, 173.9, 183.1

[0108] This is an example of synthesis of the compound 6-(n-butylamino)-1,3,5-triazine-2,4-dithiol of Comparative Example 3 represented by the following chemical formula (2-2).

[0109] [Chemical formula 10]

[0110]

[0111] The same procedure was followed except that 35.8 g (490 mmol) of butylamine (carbon number 4, straight chain) was used instead of hexylamine (carbon number 6, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), and 76.4 g of white crystals as the target substance were obtained.

[0112] The analysis results for the structural identification of the compound are shown.

[0113] 1 H-NMR (Solvent: DMSO-d6)

[0114] 0.88(t,J=7.3Hz,3H),1.29(sext,J=7.4Hz,2H),1.47(quin,J=7.3Hz,2H),3.28-3.32(m,2H),7.12(br,1H),12.22(br,1H),12.87(s,1H)

[0115] 13 C-NMR (Solvent: DMSO-d6)

[0116] 13.8, 19.5, 30.8, 40.2, 150.0, 174.1, 182.8

[0117] This is an example of synthesis of the compound 6-(n-pentylamino)-1,3,5-triazine-2,4-dithiol of Comparative Example 4 represented by the following chemical formula (2-3).

[0118] [Chemical formula 11]

[0119]

[0120] The same process was carried out except that 42.7 g (490 mmol) of pentylamine (carbon number 5, straight chain) was used instead of hexylamine (carbon number 6, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), and 100 g of white crystals as the target substance were obtained.

[0121] The analysis results for the structural identification of the compound are shown.

[0122] 1 H-NMR (Solvent: DMSO-d6)

[0123] 0.86(t,J=7.1Hz,3H),1.21-1.33(m,4H),1.48(quin,J=7.3Hz,2H),3.27-3.31(m,2H),7.11(br,1H),12.22(br,1H),12.88(s,1H)

[0124] 13 C-NMR (Solvent: DMSO-d6)

[0125] 14.1, 22.0, 28.4, 28.5, 40.5, 149.9, 173.7, 183.4

[0126] This is an example of synthesis of the compound 6-(n-dodecylamino)-1,3,5-triazine-2,4-dithiol of Comparative Example 5 represented by the following chemical formula (2-4).

[0127] [Chemical formula 12]

[0128]

[0129] The same procedure was followed except that 90.7 g (490 mmol) of dodecylamine (carbon number 12, straight chain) was used instead of hexylamine (carbon number 6, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), and 82.8 g of white crystals as the target substance were obtained.

[0130] The analysis results for the structural identification of the compound are shown.

[0131] 1 H-NMR (Solvent: DMSO-d6)

[0132] 0.85(t,J=7.0Hz,3H),1.24-1.26(m,18H),1.46-1.49(m,2H),3.27-3.31(m,2H),7.12(br,1H),12.23(br,1H),12.90(s,1H)

[0133] 13 C-NMR (Solvent: DMSO-d6)

[0134] 14.0, 22.2, 26.1, 28.6, 28.7, 28.8, 29.0, 29.0, 29.1, 29.1, 31.4, 40.3, 149.8, 174.0, 183.0

[0135] This is an example of synthesis of the compound 6-(cyclohexylamino)-1,3,5-triazine-2,4-dithiol of Comparative Example 6 represented by the following chemical formula (2-5).

[0136] [Chemical formula 13]

[0137]

[0138] The same procedure was followed except that 48.6 g (490 mmol) of cyclohexylamine (6 carbon atoms, alicyclic) was used instead of hexylamine (6 carbon atoms, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), to obtain 99.5 g of white crystals as the target substance.

[0139] The analysis results for the structural identification of the compound are shown.

[0140] 1 H-NMR (Solvent: DMSO-d6)

[0141] 1.18-1.35(m,5H),1.52-1.55(m,1H),1.63-1.66(m,2H),

[0142] 1.78-1.81(m,2H),3.79-3.81(m,1H),7.03(br,1H),11.82(br,1H),12.91(s,1H)

[0143] 13 C-NMR (Solvent: DMSO-d6)

[0144] 24.2, 25.0, 32.0, 49.2, 149.2, 173.7, 183.3

[0145] This is an example of synthesis of the compound 6-(cyclooctylamino)-1,3,5-triazine-2,4-dithiol of Comparative Example 7 represented by the following chemical formula (2-6).

[0146] [Chemical formula 14]

[0147]

[0148] The same procedure was followed except that 62.3 g (490 mmol) of cyclooctylamine (8 carbon atoms, alicyclic) was used instead of hexylamine (6 carbon atoms, straight chain) in the synthesis example of compound 6-(n-hexylamino)-1,3,5-triazine-2,4-dithiol in Example 1 represented by chemical formula (1-1), to obtain 110 g of slightly yellowish white crystals as the target substance.

[0149] The analysis results for the structural identification of the compound are shown.

[0150] 1 H-NMR (Solvent: DMSO-d6)

[0151] 1.48-1.60(m,12H),1.76-1.77(m,2H),3.98-4.03(m,1H),7.07(br,1H),11.73(br,1H),12.90(s,1H)

[0152] 13 C-NMR (Solvent: DMSO-d6)

[0153] 22.9, 24.8, 27.1, 30.9, 50.6, 148.9, 173.5, 183.1

[0154] It should be noted that 6-(di-n-butylamino)-1,3,5-triazine-2,4-dithiol (BSH) of Comparative Example 1 and 6-(anilino)-1,3,5-triazine-2,4-dithiol (hereinafter referred to as ASH; having a chemical structure in which a phenyl group (6 carbon atoms, aromatic) is used instead of a hexyl group (6 carbon atoms, linear) in the compound of Example 1 represented by the chemical formula (1-1)) of Comparative Example 8 were commercially available products.

[0155] Next, the rubber test results using the compounds are described.

[0156] Table 1 shows the proportions of the rubber compositions in Examples 1 to 6 and Comparative Examples 1 to 8. The amounts are expressed in parts by weight (phr). Examples 1 to 6 are compositions using the primary aminotriazine dithiol compounds represented by chemical formulas (1-1) to (1-6) in the present invention. In addition, Comparative Example 1 uses BSH, which is a triazine crosslinking agent commonly used in the past. Comparative Examples 2 to 7 are compositions using the primary aminotriazine dithiol compounds represented by chemical formulas (2-1) to (2-6), and Comparative Example 8 is a composition using ASH.

[0157] Each rubber composition was prepared by a conventional kneading method using an internal mixer and an open roll mill. Specifically, the chemicals in step A shown in Table 1, such as fillers, were added to chlorobutyl rubber in a Banbury mixer and kneaded.

[0158] Each crosslinking agent in step B shown in Table 1 was used to obtain each rubber composition.

[0159]

[0160] For each of the obtained compositions, a vulcanization test was performed using a vibration type vulcanization tester (rheometer test) in accordance with JIS K6300-2.

[0161] Table 2 shows ML (minimum elastic torque) and MH (maximum elastic torque) at a test temperature of 175°C and a test time of 30 minutes, as well as tc10 (10% vulcanization time) and tc90 (90% vulcanization time). Figure 1 These values ​​are shown with MH as the horizontal axis and tc90 as the vertical axis. Here, MH is shown as an index of rubber elasticity, and tc90 is shown as an index of crosslinking reaction rate.

[0162]

[0163] According to Table 2 and Figure 1 Compared with Comparative Example 1 using a conventional triazine-based crosslinking agent, Examples 1 to 6 have shorter tc90 and higher MH, and thus can undergo a crosslinking reaction in a short time and obtain a highly elastic rubber.

[0164] In addition, Comparative Examples 2 to 4 are each a compound in which R 1 The carbon atoms of the straight chain or branched hydrocarbon group are 5 or less, and the tc90 is longer than that of Comparative Example 1, so the crosslinking reaction speed is slow. 1 The straight or branched hydrocarbon group with 11 carbon atoms has a shorter tc90 than that of Comparative Example 1, so the crosslinking reaction speed is fast, but MH is 5.7 compared to 6.3 of Comparative Example 1, so the rubber elasticity is significantly reduced. 1 The number of carbon atoms is in the range of 6-10, but R 1 It is an alicyclic or aromatic hydrocarbon group, and has a longer tc90 and a smaller MH than that of Comparative Example 1. Therefore, it is found that the crosslinking reaction rate is slowed down and the rubber elasticity is reduced.

[0165] Next, the cross-linked rubber properties of each rubber composition were confirmed.

[0166] As shown in Table 1, the rubber compositions of Examples 1, 3, 4, 6 and Comparative Examples 1, 2, 3, and 5 were crosslinked using a vulcanization press, with the crosslinking temperature being constant at 175°C and the vulcanization time being set to 1.5 times of each tc90.

[0167] Each of the obtained crosslinked rubbers was used as a test sample, and physical tests on tensile properties and rubber hardness were performed in accordance with JIS K6251 and JIS K6253.

[0168] In addition, the obtained cross-linked rubber was tested for its solubility in water (potassium permanganate consumption).

[0169] Specifically, a 2 mm thick cross-linked rubber sheet was punched into one circular piece with a diameter of 4.5 cm and two circular pieces with a diameter of 3.6 cm. The extracted water obtained by extracting these samples with 160 mL of 80° C. pure water for 6 hours was used as a test sample, and the potassium permanganate consumption was measured in accordance with JIS T9010.

[0170] The test results are shown in Table 3.

[0171] [Table 3]

[0172]

[0173] According to Table 3, all Examples have higher rubber hardness and intermediate stress (200%) than Comparative Example 1 containing a conventional crosslinking agent (BSH), and thus exhibit high rubber elasticity.

[0174] Furthermore, it was shown that the solubility in water was also smaller than that of Comparative Example 1 containing a conventional crosslinking agent (BSH).

[0175] In summary, among the crosslinking agents used in the formulation of chlorinated butyl rubber compositions, the primary aminotriazine dithiol compound represented by the above chemical formula (1) is shown to accelerate the crosslinking reaction rate and to provide a rubber product having high rubber elasticity and low elution of additives, compared with the conventional 6-(dibutylamino)-1,3,5-triazine-2,4-dithiol (BSH).

Claims

1. A cross-linking agent for chlorinated butyl rubber represented by the following chemical formula (1): [Chemical formula 1] in, R 1 It represents a straight-chain or branched hydrocarbon group having 6 to 10 carbon atoms.

2. A rubber composition, characterized in that The compound represented by the above chemical formula (1) is blended in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the chlorinated butyl rubber.

3. A rubber product obtained by crosslinking the rubber composition according to claim 2.

4. A medical rubber composition, which is composed of the rubber composition according to claim 2.

5. A medical rubber product obtained by crosslinking the medical rubber composition according to claim 4.

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