NOVEL CARBAMATE ESTER COMPOUND AND ACRYLIC RUBBER COMPOSITION CONTAINING THE SAME

Abstract

A carbamate ester compound represented by the general formula:

Z—OCONH(CH.sub.2).sub.nNHCOO—Z  [I]

wherein Z is [i], [ii], or [iii] below, and n is an integer of 2 to 10,

##STR00001##

(wherein R.sup.1 and R.sup.2 are each independently a lower alkyl group having 1 to 5 carbon atoms, R.sup.3 is a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, and a is 1 or 2). The carbamate ester compound is used as a vulcanizing agent for carboxyl group-containing acrylic rubber and improves the delay of the vulcanization rate by scorch suppression.

Claims

10. A carbamate ester compound represented by the general formula:
Z—OCONH(CH.sub.2).sub.nNHCOO—Z  [I] wherein Z is [i], [ii], or [iii] below, and n is an integer of 2 to 10, ##STR00018## wherein: R.sup.1 is a lower alkyl group having 1 to 5 carbon atoms, R.sup.3 is a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, and a is 2.

11. The carbamate ester compound according to claim 10, wherein n in the formula [I] is 6.

12. The carbamate ester compound according to claim 10, which is used as a vulcanizing agent for carboxyl group-containing acrylic rubber.

13. An acrylic rubber composition compound 0.1 to 10 parts by weight of a carbamate ester compound represented by the general formula:
Z—OCONH(CH.sub.2).sub.nNHCOO—Z  [I] wherein Z is [i], [ii], or [iii] below, and n is an integer of 2 to 10, ##STR00019## wherein: R.sup.1 and R.sup.2 are each independently a lower alkyl group having 1 to 5 carbon atoms, R.sup.3 is a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, and a is 1 or 2, as a vulcanizing agent based on 100 parts by weight of carboxyl group-containing acrylic rubber.

14. The acrylic rubber composition according to claim 13, wherein 0.1 to 10 parts by weight of a guanidine compound vulcanization accelerator is further compounded.

15. The acrylic rubber composition according to claim 13, wherein 0.01 to 2 parts by weight of a diazabicycloalkene compound vulcanization accelerator is further compounded.

16. The acrylic rubber composition according to claim 13, wherein 0.1 to 5 parts by weight of an organic acid salts or inorganic acid salts of diazabicycloalkene compound vulcanization accelerator is further compounded.

17. A vulcanization molded article molded with mold from the acrylic rubber composition according to claim 13.

18. A vulcanization molded article extrusion-molded from the acrylic rubber composition according to claim 13.

Description

EXAMPLES

[0055] The following describes the present invention with reference to Examples.

Example 1

[0056] In a 200 ml eggplant shaped flask, 11.00 g (74.7 mmol) of indolylmethanol (produced by Tokyo Chemical Industry Co., Ltd.) and 24 g of methyl ethyl ketone were charged, and stirred for dissolution in a water bath at 25° C. Then, 2 g of methyl ethyl ketone solution with 144 mg (0.228 mmol) of dibutyltin dilaurate (produced by FUJIFILM Wako Pure Chemical Corporation) dissolved therein was added. Subsequently, 24 g of methyl ethyl ketone solution with 6.00 g (35.6 mmol) of hexamethylene diisocyanate (produced by Tokyo Chemical Industry Co., Ltd.) was added dropwise in 2 or 3 batches, and the mixture was allowed to stand for 5 minutes.

[0057] After the completion of the reaction, the resultant was dried under reduced pressure at room temperature for 5 hours, thereby obtaining 17.24 g of a light brown crude powdered solid [carbamate ester compound A].

##STR00008##

[0058] The structure of the obtained solid was identified using .sup.1H NMR (Aceton-d.sub.6) and FT-IR.

##STR00009##

[0059] .sup.1H NMR: (a) 7.7 ppm (d 2H) [0060] (b) 7.1 ppm (t 2H) [0061] (c), (d) 7.4 ppm (m 4H) [0062] (e) 10.2 ppm (s 2H) [0063] (f) 7.0 ppm (t 2H) [0064] (g) 5.3 ppm (s 4H) [0065] (h) 6.1 ppm (s 2H) [0066] (i) 3.1 ppm (q 4H) [0067] (j) 1.5 ppm (m 4H) [0068] (k) 1.3 ppm (m 4H)

[0069] FT-IR: 3385 cm.sup.−1: N—H stretching vibration of secondary heteroaromatic amine [0070] 3324 cm.sup.−1: N—H stretching vibration derived from urethane bond [0071] 1686 cm.sup.−1: C═O stretching vibration derived from urethane bond

Example 2

[0072] In a 50 ml eggplant shaped flask, 6.23 g (56.1 mmol) of N-methyl-2-hydroxymethylpyrrole (produced by Tokyo Chemical Industry Co., Ltd.) was charged, and 2 g of methyl ethyl ketone solution with 108 mg (0.171 mmol) of dibutyltin dilaurate dissolved therein was added. Subsequently, 6 g of methyl ethyl ketone solution with 4.50 g (26.7 mmol) of hexamethylene diisocyanate dissolved therein was added dropwise, and the mixture was stirred in a water bath at 25° C. for 1.5 hours.

[0073] After the completion of the reaction, the resultant was dried under reduced pressure at room temperature for 8 hours, thereby obtaining 10.79 g (yield: 99%) of a light brown powdered solid [carbamate ester compound B].

##STR00010##

[0074] The structure of the obtained solid was identified using .sup.1H NMR and FT-IR.

##STR00011##

[0075] .sup.1H NMR: (a) 3.6 ppm (s 6H) [0076] (b) 6.6 ppm (t 2H) [0077] (c) 6.2 ppm (q 2H) [0078] (d) 6.1 ppm (t 2H) [0079] (e) 5.0 ppm (s 4H) [0080] (f) 6.6 ppm (s 2H) [0081] (g) 3.1 ppm (m 4H) [0082] (h) 1.5 ppm (m 4H) [0083] (i) 1.3 ppm (m 4H)

[0084] FT-IR: 3325 cm.sup.−1: N—H stretching vibration derived from urethane bond [0085] 1679 cm.sup.−1: C═O stretching vibration derived from urethane bond

Example 3

[0086] In a 100 ml two-necked eggplant shaped flask, 11.16 g (56.25 mmol) of 1,1-diphenylethanol (produced by Tokyo Chemical Industry Co., Ltd.) was charged, and 2 g of methyl ethyl ketone solution with 360 mg (0.570 mmol) of dibutyltin dilaurate dissolved therein was added. Subsequently, 4 g of methyl ethyl ketone solution with 4.50 g (26.7 mmol) of hexamethylene diisocyanate dissolved therein was added dropwise, and the mixture was stirred for 5.5 hours in the reactor warmed at 80° C.

[0087] After the completion of the reaction, the insoluble portion was filtered and washed with n-hexane, and the filtrate was dried under reduced pressure at room temperature for 8 hours, thereby obtaining 14.25 g (yield: 94%) of a white powdered solid [carbamate ester compound C].

##STR00012##

[0088] The structure of the obtained solid was identified using .sup.1H NMR and FT-IR.

##STR00013##

[0089] .sup.1H NMR: (a), (b), (c) 7.2-7.3 ppm (m 20H) [0090] (d) 2.2 ppm (s 6H) [0091] (c), (d) 7.4 ppm (m 4H) [0092] (e) 4.8 ppm (s 2H) [0093] (f) 3.0 ppm (m 4H) [0094] (g) 1.4 ppm (m 4H) [0095] (h) 1.2 ppm (m 4H)

[0096] FT-IR: 3281 cm.sup.−1: N—H stretching vibration derived from urethane bond [0097] 1690 cm.sup.−1: C═O stretching vibration derived from urethane bond

Example 4

[0098] In a 50 ml eggplant shaped flask, 8.43 g (56.1 mmol) of α,α,4-trimethyl-dimethylbenzyl alcohol (produced by Tokyo Chemical Industry Co., Ltd.), 360 mg (0.570 mmol) of dibutyltin dilaurate, and 4.50 g (26.7 mmol) of hexamethylene diisocyanate were charged, and the mixture was stirred for 2.5 hours in the reactor warmed at 80° C.

[0099] After the completion of the reaction, the resultant was cooled, thereby obtaining 12.06 g (yield: 91%) of a white powdered solid [carbamate ester compound D].

##STR00014##

[0100] The structure of the obtained solid was identified using .sup.1H NMR and FT-IR.

##STR00015##

[0101] .sup.1H NMR: (a) 2.3 ppm (s 6H) [0102] (b) 7.1 ppm (t 2H) [0103] (c) 7.2 ppm (m 4H) [0104] (d) 1.7 ppm (s 12H) [0105] (e) 4.7 ppm (m 2H) [0106] (f) 3.0 ppm (m 4H) [0107] (g) 1.4 ppm (m 4H) [0108] (h) 1.3 ppm (m 4H)

[0109] FT-IR: 3307 cm.sup.−1: N—H stretching vibration derived from urethane bond [0110] 1687 cm.sup.−1: C═O stretching vibration derived from urethane bond

Example 5

[0111]

TABLE-US-00001 Carboxyl group-containing acrylic rubber 100 parts by weight (Noxtite PA-522HF, produced by Ummatec Co., Ltd.) FEF carbon black (Seast G-SO, produced by 55 parts by weight Tokai Carbon Co., Ltd.) Stearic acid (DTST, produced by 1 part by weight Miyoshi Oil & Fat Co., Ltd.) 4,4′-(α,α-dimethylbenzyl)diphenylamine 2 parts by weight (Nocrac CD, produced by Ouchi Shinko Chemical Industrial Co., Ltd.) Carbamate ester compound A 1.7 parts by weight 1,3-Di-o-tolylguanidine 2 parts by weight (Nocceler DT, produced by Ouchi Shinko Chemical Industrial Co., Ltd.)

[0112] Among the above components, the components other than the vulcanizing agent and the vulcanization accelerator were each kneaded with a Banbury mixer. Then, the vulcanizing agent and the vulcanization accelerator were added using an open roll. The acrylic rubber composition prepared in this manner was vulcanized by press vulcanization (primary vulcanization) at 180° C. for 8 minutes and oven vulcanization (secondary vulcanization) at 175° C. for 4 hours.

[0113] The vulcanization characteristics and vulcanizate physical properties of the compound, which was the acrylic rubber composition, were measured as described below.

[0114] Mooney scorch test: according to JIS K6300-1 corresponding to ISO 289 (125° C.)

[0115] The longer the t5 value (unit: minute), the less concern of compound scorch during molding and the less defects caused by scorching.

[0116] In general, when the t5 value is 10 minutes or more, defects caused by scorching during injection molding, compression molding or extrusion molding decrease.

[0117] ML.sub.min: This is the minimum value of the Mooney viscosity and becomes an index of processability

[0118] Vulcanization test: according to JIS K6300-2 corresponding to ISO 6502 (180° C., 12 minutes)

[0119] Rotorless Rheometer RLR-3, produced by Toyo Seiki Seisaku-sho, Ltd., was used.

[0120] ML: Minimum torque

[0121] MH: Maximum torque

[0122] tc10: Time required for vulcanization torque to reach ML+(MH−ML)×0.1

[0123] tc90: Time required for vulcanization torque to reach ML+(MH−ML)×0.9

[0124] Evaluation of the vulcanization rate can be determined by tc10, tc90, and ME (MH-ML) in the vulcanization test. The vulcanization rate is higher as tc10 and tc90 are shorter and ME is larger.

[0125] Normal state value: according to JIS K6251 corresponding to ISO 37, and JIS K6253 corresponding to ISO 7619-1

[0126] Compression set: according to JIS K6262 corresponding to ISO 815-1 (175° C., 70 hours)

[0127] Air oven aging test: according to JIS K6257 corresponding to ISO 188 (175° C., 70 hours); normal state value changes were measured.

Example 6

[0128] In Example 5, 1.5 parts by weight of the carbamate ester compound B was used in place of the carbamate ester compound A.

Example 7

[0129] In Example 5, 2.1 parts by weight of the carbamate ester compound C was used in place of the carbamate ester compound A.

Example 8

[0130] In Example 5, 1.8 parts by weight of the carbamate ester compound D was used in place of the carbamate ester compound A.

Comparative Example 1

[0131] In Example 5, 0.6 parts by weight of an aliphatic amine vulcanizing agent (CHEMINOX AC-6F, produced by Unimatec Co., Ltd.) was used in place of the carbamate ester compound A.

Comparative Example 2

[0132] In Example 5, 1.2 parts by weight of an aromatic diamine vulcanizing agent (CHEMINOX CLP5000, produced by Unimatec Co., Ltd.) was used in place of the carbamate ester compound A.

Comparative Example 3

[0133] In Comparative Example 1, 1 part by weight of stearylamine (Farmin 80S, produced by Kao Corporation) was further used as a vulcanization retarder.

Example 9

[0134] In Example 7, 1 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 dibasic acid salt-amorphous silica (weight ratio 70:30) mixture (Vulcofac ACT55, produced by Safic Alcan) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Example 10

[0135] In Example 8, 1 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 dibasic acid salt-amorphous silica (weight ratio 70:30) mixture (Vulcofac ACT55) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Comparative Example 4

[0136] In Comparative Example 1, 1 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 dibasic acid salt-amorphous silica (weight ratio 70:30) mixture (Vulcofac ACT55) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Comparative Example 5

[0137] In Comparative Example 3, 1 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 dibasic acid salt-amorphous silica (weight ratio 70:30) mixture (Vulcofac ACT55) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

[0138] Following Table 1 shows the results obtained respectively in the above Examples 5 to 10 and Comparative Examples 1 to 5.

TABLE-US-00002 TABLE 1 Comparative Comparative Measurement Example Example Example Example item 5 6 7 8 1 2 3 9 10 4 5 Mooney scorch test ML.sub.min (pts) 33 32 29 29 32 32 32 29 28 36 36 t5 (min) 7.9 8.0 18.6 26.3 6.8 13.5 8.1 17.4 18.3 5.4 6.2 Vulcanization test tc10 (min) 0.60 0.62 0.89 1.12 0.58 1.19 0.69 0.99 1.05 0.51 0.59 tc90 (min) 4.69 6.34 6.09 6.58 4.26 8.25 6.54 6.94 7.14 5.08 6.46 ML (N .Math. m) 0.14 0.13 0.12 0.12 0.13 0.13 0.13 0.13 0.12 0.14 0.14 MH (N .Math. m) 0.71 0.69 0.76 0.71 0.78 0.35 0.64 0.78 0.75 0.82 0.67 ME(MH − 0.57 0.56 0.64 0.59 0.65 0.22 0.51 0.65 0.63 0.68 0.53 ML) (N .Math. m) Normal state value Hardness 63 66 65 61 61 67 63 66 65 61 64 (Duro A) 100% 4.1 5.0 4.9 4.1 3.7 4.8 3.5 5.2 4.7 4.3 4.0 Modulus (MPa) Breaking 11.2 12.0 10.8 10.5 11.4 11.9 10.8 11.5 11.4 11.9 11.3 Strength (MPa) Elongation 250 210 220 250 240 220 270 200 210 210 230 at break (%) Compression set 175° C., 14 18 16 16 12 15 23 19 16 13 20 70 hrs (%) Normal state value changes after 70 hrs at 175° C. Hardness +2 +2 +2 +4 +2 +2 −3 +1 +1 +3 +2 (Duro A) 100% −23 −20 −15 −11 −12 −5 −16 −14 −21 −18 −20 Modulus (MPa) Breaking 18 −12 −9 −10 −16 −9 −18 −15 −17 −19 −18 Strength (MPa) Elongation +20 +14 +18 +4 +13 0 +7 +20 +14 +19 +17 at break (%)

Example 11

[0139] In Example 6, 1 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 (Rhenogran XLA-60, produced by LANXESS) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Example 12

[0140] In Example 7, 1 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 (Rhenogran XLA-60) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Example 13

[0141] In Example 8, 1 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 (Rhenogran XLA-60) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Comparative Example 6

[0142] In Comparative Example 1, 1 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 (Rhenogran XLA-60) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Comparative Example 7

[0143] In Comparative Example 3, 1 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 (Rhenogran XLA-60) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Example 14

[0144] In Example 7, 0.5 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 (DBU produced by San-Apro Ltd.) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Example 15

[0145] In Example 8, 0.5 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 (DBU) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Comparative Example 8

[0146] In Comparative Example 1, 0.5 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 (DBU) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Comparative Example 9

[0147] In Comparative Example 3, 0.5 part by weight of 1,8-diazabicyclo[5.4.0]undecene-7 (DBU) was used as a vulcanization accelerator, in place of 1,3-di-o-tolylguanidine.

Comparative Example 10

[0148] In Example 1, the amount of FEF carbon black was changed to 60 parts by weight, and 1.5 parts by weight of HMDA-Fmoc was used in place of the carbamate ester compound A.

##STR00016##

Comparative Example 11

[0149] In Example 1, the amount of FEF carbon black was changed to 60 parts by weight, and 1.5 parts by weight of HMDA-Dmoc was used in place of the carbamate ester compound A.

##STR00017##

[0150] Following Table 2 shows the results obtained respectively in the above Examples 11 to 15 and Comparative Examples 6 to 11.

TABLE-US-00003 TABLE 2 Comparative Comparative Measurement Example Example Example Example item 11 12 13 6 7 14 15 8 9 10 11 Mooney scorch test ML.sub.min (pts) 34 30 30 38 36 35 34 41 37 36 36 t5 (min) 9.3 24.6 25.2 6.0 7.8 18.0 23.3 4.0 5.2 >60 >60 Vulcanization test tc10 (min) 0.83 1.24 1.30 0.65 0.70 1.08 1.20 0.36 0.47 2.74 1.65 tc90 (min) 7.39 7.39 7.52 6.31 7.25 6.33 6.62 3.53 4.79 9.20 8.92 ML (N .Math. m) 0.13 0.12 0.12 0.14 0.14 0.13 0.13 0.15 0.14 0.16 0.15 MH (N .Math. m) 0.70 0.70 0.67 0.77 0.63 0.82 0.81 0.88 0.69 0.41 0.32 ME(MH − 0.57 0.58 0.55 0.63 0.49 0.69 0.68 0.73 0.55 0.25 0.17 ML) (N .Math. m) Normal state value Hardness 66 65 64 61 62 69 66 65 66 65 62 (Duro A) 100% 4.9 4.5 4.2 4.5 3.9 5.9 5.1 5.7 4.3 2.5 2.8 Modulus (MPa) Breaking 10.8 11.0 10.3 11.7 11.3 11.7 11.4 12.3 11.6 9.2 8.9 Strength (MPa) Elongation 200 230 220 220 230 190 200 180 220 310 340 at break(%) Compression set 175° C., 23 24 20 16 22 23 19 15 21 15 26 70 hrs (%) Normal state value changes after 70 hrs at 175° C. Hardness +4 +0 +3 +4 +3 +4 +4 +0 +1 — — (Duro A) 100% −15 −21 −2 −20 −13 −29 −16 −30 −19 — — Modulus (MPa) Breaking −9 −18 −5 −19 −18 −17 −14 −17 −17 — — Strength (MPa) Elongation +15 +13 +18 +18 +17 +21 +10 +28 +9 — — at break (%)