WO2024024496A1 - Vulcanization method - Google Patents
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- WO2024024496A1 WO2024024496A1 PCT/JP2023/025589 JP2023025589W WO2024024496A1 WO 2024024496 A1 WO2024024496 A1 WO 2024024496A1 JP 2023025589 W JP2023025589 W JP 2023025589W WO 2024024496 A1 WO2024024496 A1 WO 2024024496A1
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- vulcanization
- rubber composition
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- vulcanization method
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- 238000004073 vulcanization Methods 0.000 title claims abstract description 65
- 238000000034 method Methods 0.000 title claims abstract description 41
- 229920001971 elastomer Polymers 0.000 claims abstract description 46
- 239000000203 mixture Substances 0.000 claims abstract description 46
- 239000005060 rubber Substances 0.000 claims abstract description 46
- 239000006229 carbon black Substances 0.000 claims abstract description 19
- 229920003244 diene elastomer Polymers 0.000 claims abstract description 11
- 230000001678 irradiating effect Effects 0.000 claims abstract description 7
- 235000019241 carbon black Nutrition 0.000 description 17
- 239000003795 chemical substances by application Substances 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 7
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- 239000006237 Intermediate SAF Substances 0.000 description 4
- 239000005062 Polybutadiene Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 229920003049 isoprene rubber Polymers 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 229920002857 polybutadiene Polymers 0.000 description 4
- 238000010408 sweeping Methods 0.000 description 4
- 244000043261 Hevea brasiliensis Species 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004898 kneading Methods 0.000 description 3
- 229920003052 natural elastomer Polymers 0.000 description 3
- 229920001194 natural rubber Polymers 0.000 description 3
- 229920002943 EPDM rubber Polymers 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000003712 anti-aging effect Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000004132 cross linking Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 229920001084 poly(chloroprene) Polymers 0.000 description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- IPJGAEWUPXWFPL-UHFFFAOYSA-N 1-[3-(2,5-dioxopyrrol-1-yl)phenyl]pyrrole-2,5-dione Chemical compound O=C1C=CC(=O)N1C1=CC=CC(N2C(C=CC2=O)=O)=C1 IPJGAEWUPXWFPL-UHFFFAOYSA-N 0.000 description 1
- XQUPVDVFXZDTLT-UHFFFAOYSA-N 1-[4-[[4-(2,5-dioxopyrrol-1-yl)phenyl]methyl]phenyl]pyrrole-2,5-dione Chemical compound O=C1C=CC(=O)N1C(C=C1)=CC=C1CC1=CC=C(N2C(C=CC2=O)=O)C=C1 XQUPVDVFXZDTLT-UHFFFAOYSA-N 0.000 description 1
- DGPKJHGPIAETKL-UHFFFAOYSA-N 2,2-bis(sulfanylidene)-1,3,2-dioxathionane;sodium;dihydrate Chemical compound O.O.[Na].[Na].S=S1(=S)OCCCCCCO1 DGPKJHGPIAETKL-UHFFFAOYSA-N 0.000 description 1
- DMWVYCCGCQPJEA-UHFFFAOYSA-N 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane Chemical compound CC(C)(C)OOC(C)(C)CCC(C)(C)OOC(C)(C)C DMWVYCCGCQPJEA-UHFFFAOYSA-N 0.000 description 1
- XMNIXWIUMCBBBL-UHFFFAOYSA-N 2-(2-phenylpropan-2-ylperoxy)propan-2-ylbenzene Chemical compound C=1C=CC=CC=1C(C)(C)OOC(C)(C)C1=CC=CC=C1 XMNIXWIUMCBBBL-UHFFFAOYSA-N 0.000 description 1
- WFUGQJXVXHBTEM-UHFFFAOYSA-N 2-hydroperoxy-2-(2-hydroperoxybutan-2-ylperoxy)butane Chemical compound CCC(C)(OO)OOC(C)(CC)OO WFUGQJXVXHBTEM-UHFFFAOYSA-N 0.000 description 1
- BIISIZOQPWZPPS-UHFFFAOYSA-N 2-tert-butylperoxypropan-2-ylbenzene Chemical compound CC(C)(C)OOC(C)(C)C1=CC=CC=C1 BIISIZOQPWZPPS-UHFFFAOYSA-N 0.000 description 1
- FRIBMENBGGCKPD-UHFFFAOYSA-N 3-(2,3-dimethoxyphenyl)prop-2-enal Chemical compound COC1=CC=CC(C=CC=O)=C1OC FRIBMENBGGCKPD-UHFFFAOYSA-N 0.000 description 1
- MIIBUHIQXLFJFP-UHFFFAOYSA-N 3-methyl-1-[[3-[(3-methyl-2,5-dioxopyrrol-1-yl)methyl]phenyl]methyl]pyrrole-2,5-dione Chemical compound O=C1C(C)=CC(=O)N1CC1=CC=CC(CN2C(C(C)=CC2=O)=O)=C1 MIIBUHIQXLFJFP-UHFFFAOYSA-N 0.000 description 1
- HLBZWYXLQJQBKU-UHFFFAOYSA-N 4-(morpholin-4-yldisulfanyl)morpholine Chemical compound C1COCCN1SSN1CCOCC1 HLBZWYXLQJQBKU-UHFFFAOYSA-N 0.000 description 1
- ZZMVLMVFYMGSMY-UHFFFAOYSA-N 4-n-(4-methylpentan-2-yl)-1-n-phenylbenzene-1,4-diamine Chemical compound C1=CC(NC(C)CC(C)C)=CC=C1NC1=CC=CC=C1 ZZMVLMVFYMGSMY-UHFFFAOYSA-N 0.000 description 1
- 239000004342 Benzoyl peroxide Substances 0.000 description 1
- OMPJBNCRMGITSC-UHFFFAOYSA-N Benzoylperoxide Chemical compound C=1C=CC=CC=1C(=O)OOC(=O)C1=CC=CC=C1 OMPJBNCRMGITSC-UHFFFAOYSA-N 0.000 description 1
- 235000021355 Stearic acid Nutrition 0.000 description 1
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 235000019400 benzoyl peroxide Nutrition 0.000 description 1
- 229920005549 butyl rubber Polymers 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- LSXWFXONGKSEMY-UHFFFAOYSA-N di-tert-butyl peroxide Chemical compound CC(C)(C)OOC(C)(C)C LSXWFXONGKSEMY-UHFFFAOYSA-N 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- DEQZTKGFXNUBJL-UHFFFAOYSA-N n-(1,3-benzothiazol-2-ylsulfanyl)cyclohexanamine Chemical compound C1CCCCC1NSC1=NC2=CC=CC=C2S1 DEQZTKGFXNUBJL-UHFFFAOYSA-N 0.000 description 1
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 1
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 1
- 150000001451 organic peroxides Chemical class 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000013040 rubber vulcanization Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- -1 softeners Substances 0.000 description 1
- 239000008117 stearic acid Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000004636 vulcanized rubber Substances 0.000 description 1
- 235000014692 zinc oxide Nutrition 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/28—Treatment by wave energy or particle radiation
Definitions
- the present invention relates to a vulcanization method.
- Patent Document 1 discloses that the total heating time can be shortened by using microwave energy for at least part of the thermal energy required in manufacturing a pneumatic tire.
- Patent Document 1 heating by microwave energy is finished before the start of the vulcanization reaction.
- the vulcanization reaction was performed by irradiating microwaves, it was extremely difficult to control the vulcanization reaction, and there were problems such as uneven vulcanization and local scorching. was there. Due to such problems of uneven vulcanization, rubber vulcanization using microwaves has not yet been fully put into practical use, and the use of microwaves is limited to preheating before vulcanization. There was a situation.
- an object of the present invention is to provide a vulcanization method that can uniformly vulcanize a rubber composition by microwave irradiation.
- the present inventors focused on the fact that carbon black can serve as a heating element with excellent microwave absorption characteristics, and conducted extensive studies. They discovered that when heating (vulcanizing) a rubber composition containing carbon black by microwave irradiation, uniform vulcanization can be achieved by sweeping the frequency of the microwave in a predetermined manner. I ended up doing it.
- the gist of the present invention for achieving the above object is as follows.
- a vulcanization method in which a rubber composition containing a diene rubber and carbon black is vulcanized by irradiation with microwaves, The frequency of the microwave irradiated to the rubber composition is changed by a frequency change width selected from a range of more than 0 Hz and less than 1000 Hz every time a time interval selected from a range of more than 0 ⁇ sec and less than 100 ⁇ sec passes.
- a vulcanization method characterized by:
- a vulcanization method capable of uniformly vulcanizing a rubber composition by microwave irradiation.
- FIG. 2 is a schematic diagram of an example showing a frequency sweep pattern of microwaves irradiated to a rubber composition according to the present invention.
- a vulcanization method is a vulcanization method in which a rubber composition containing a diene rubber and carbon black is vulcanized by irradiating microwaves, The frequency of the microwave irradiated to the rubber composition is changed by a frequency change width selected from a range of more than 0 Hz and less than 1000 Hz every time a time interval selected from a range of more than 0 ⁇ sec and less than 100 ⁇ sec passes. It is characterized by
- microwave refers to electromagnetic waves with a frequency of 300 MHz to 300 GHz.
- FIG. 1 is a schematic diagram of an example showing a frequency sweep pattern of microwaves irradiated to a rubber composition according to the vulcanization method of the present embodiment.
- the frequency of the microwave irradiated to the rubber composition is increased by a constant frequency change width (F) every time a constant time interval (T) elapses.
- the mechanism by which the rubber composition can be uniformly vulcanized by the vulcanization method of this embodiment is as follows. Normally, when a rubber composition containing carbon black is irradiated with microwaves, the rubber composition is directly irradiated with microwaves, and the rubber composition is irradiated with microwaves that are reflected at least once within a microwave generator. Interference effects occur due to the microwaves generated. In this respect, for example, if the frequency of microwaves is constant, areas where interference is likely to occur and areas where interference is unlikely to occur will be fixedly unevenly distributed in the rubber composition, resulting in overheating in some areas and underheating in other areas. A situation may arise where: This situation becomes particularly noticeable at temperatures of 120° C.
- the frequency of the irradiated microwave is swept in a predetermined manner, so that local concentration of energy absorption in the rubber composition can be effectively avoided. ) is considered to be able to be made uniform.
- the vulcanization method of this embodiment it is not essential to move or rotate the object to be heated within the apparatus for the purpose of avoiding uneven heating (as in a turntable microwave oven).
- VFM variable frequency microwave generator
- the time interval (T) is the time between timings at which the frequency is changed, or in other words, the time at which microwaves of a constant frequency are irradiated.
- the time interval (T) is selected from a range of more than 0 ⁇ sec and less than 100 ⁇ sec. If the time interval (T) exceeds 100 ⁇ sec, there is a possibility that concentration of heat in some parts of the rubber composition cannot be sufficiently suppressed. Further, the lower limit of the time interval (T) may be more than 0 ⁇ sec, and may be adjusted as appropriate depending on the specifications of the device used.
- the time interval (T) is preferably 1 ⁇ sec or more from the viewpoint of efficiency of microwave irradiation. From the same viewpoint, the time interval (T) is preferably selected from the range of 3 to 50 ⁇ sec, more preferably selected from the range of 5 to 30 ⁇ sec, and more preferably selected from the range of 10 to 25 ⁇ sec. More preferred.
- the time interval (T) may be constant each time as shown in FIG. 1, or may be different each time. However, in the vulcanization method of this embodiment, it is preferable that the time interval (T) is constant each time from the viewpoint of achieving uniform vulcanization more effectively.
- the frequency change width (F) is selected from a range of more than 0 Hz and less than 1000 Hz. If the frequency does not change at all (if the frequency change width (F) is 0 Hz), heat will be concentrated in some parts of the rubber composition. Furthermore, if the frequency change width (F) exceeds 1000 Hz, the stability of microwave irradiation may deteriorate, which may adversely affect uniform vulcanization. From the same viewpoint, the frequency change width (F) is preferably selected from the range of 10 to 500 Hz, more preferably selected from the range of 50 to 350 Hz, and preferably selected from the range of 100 to 260 Hz. is even more preferable.
- the frequency change width (F) may be constant each time as shown in FIG. 1, or may be different each time.
- the frequency change width (F) is constant each time.
- the frequency change by the frequency change width (F) may be increased every time as shown in FIG. 1, or may be decreased every time. , the increase or decrease may be different each time. However, in the vulcanization method of this embodiment, it is preferable to increase the frequency by the frequency change width (F) each time.
- variable frequency microwave generators usually have upper and lower limits of variable frequency based on the device specifications. Therefore, if such a variable frequency microwave generator is used and the frequency is increased each time, the frequency may reach or be close to the upper limit of the variable frequency. In this case, once the frequency is switched to the lower limit of the variable frequency or around it, the frequency may be increased again each time. A similar method may be used when lowering the frequency each time.
- the frequency range of the microwave is not particularly limited, and may be selected as appropriate based on the specifications of the microwave generator used (in particular, the type of oscillator or amplifier). can.
- the duration of the operation of irradiating microwaves while sweeping the frequency in a predetermined manner is preferably 100 seconds or more, and preferably 200 seconds or more, although it is not particularly limited. More preferably, the time is 300 seconds or more. In this case, the degree of vulcanization of the rubber composition can be more fully increased.
- the temperature of the rubber composition may be monitored during irradiation with microwaves while sweeping the frequency in a predetermined manner. By monitoring the temperature of the rubber composition, uniform vulcanization can be achieved more reliably.
- the rate of temperature increase of the rubber composition may be controlled when irradiating with microwaves. In that case, the temperature increase rate can be controlled, for example, by finely adjusting the microwave irradiation output (W).
- the control method for the temperature increase rate is not particularly limited, but may be PID control. Alternatively, the temperature increase rate can also be controlled by switching on/off the microwave irradiation. The temperature increase rate can be selected, for example, from a range of 0.05° C./second to 0.5° C./second.
- the highest temperature reached when actually vulcanizing the rubber composition is not particularly limited and can be appropriately selected depending on the purpose, but usually
- the temperature is preferably 140°C or higher, preferably 190°C or lower, and more preferably 160°C or lower.
- the rubber composition to be vulcanized used in the vulcanization method of this embodiment contains at least diene rubber and carbon black. Further, the rubber composition to be vulcanized may further contain a vulcanizing agent, other components, etc. as necessary.
- diene rubber examples include natural rubber (NR), butadiene rubber (BR), isoprene rubber (IR), styrene-butadiene rubber (SBR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), and halogen rubber.
- NR natural rubber
- BR butadiene rubber
- IR isoprene rubber
- SBR styrene-butadiene rubber
- EPDM ethylene-propylene-diene rubber
- CR chloroprene rubber
- halogen rubber butyl rubber, acrylonitributylene butadiene rubber (NBR), and the like.
- NBR acrylonitributylene butadiene rubber
- At least one of natural rubber, butadiene rubber, isoprene rubber, and styrene-butadiene rubber is used as the diene rubber. It is preferable to use
- carbon black examples include GPF, FEF, HAF, ISAF, and SAF grade carbon black. These carbon blacks may be used alone or in combination of two or more.
- the content of carbon black in the rubber composition is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of more reliably enjoying the effect of uniform vulcanization by the vulcanization method of the present invention. , preferably 10 parts by mass or more, more preferably 30 parts by mass or more, based on 100 parts by mass of diene rubber. Further, from the viewpoint of maintaining the mechanical properties of the resulting vulcanized rubber composition, the content of carbon black in the rubber composition is preferably 120 parts by mass or less, and 70 parts by mass or less, based on 100 parts by mass of diene rubber. It is more preferable that the amount is less than 1 part.
- the rubber composition contains a vulcanizing agent.
- vulcanizing agent include sulfur and sulfur-based vulcanizing agents such as morpholine disulfide; benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, methyl ethyl ketone peroxide, cumene hydro Peroxide, organic peroxides such as 2,5-dimethyl-2,5-di(t-butylperoxy)hexane; and the like.
- vulcanizing agent examples include hexamethylene bisthiosulfate disodium salt dihydrate, 1,3-bis(citraconimidomethyl)benzene, 4,4'-diphenylmethane bismaleimide, m-phenylene bismaleimide, etc. It will be done. These vulcanizing agents may be used alone or in combination of two or more.
- the content of the vulcanizing agent in the rubber composition is not particularly limited and can be appropriately selected depending on the purpose, for example, 0.1 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of diene rubber. It can be done.
- ingredients include fillers other than carbon black (such as silica), vulcanization aids such as stearic acid, vulcanization accelerators, vulcanization accelerators such as zinc white, anti-aging agents, softeners, and plasticizers. , processability improvers, etc., and these can be contained in appropriate amounts.
- the rubber composition to be vulcanized can be obtained by blending and kneading the above-mentioned components according to a conventional method using a kneading machine such as a roll, an internal mixer, or a Banbury rotor. .
- the shape of the rubber composition to be vulcanized is not particularly limited.
- the rubber composition to be vulcanized can be made into a pre-molded body, and in particular, even if it is a pre-molded body with a complicated shape, which conventionally was prone to non-uniform heating, it can be uniformly heated.
- the vulcanized product can be vulcanized to give a desired vulcanized molded product.
- metal parts may be included in the rubber composition to be vulcanized.
- the sweep mode of the frequency of the irradiated microwave is optimized, it is expected that problems such as arcing in metal parts can be suppressed.
- a rubber composition was prepared by kneading according to a conventional method using the formulation shown in Table 1.
- Isoprene rubber JSR Corporation, IR2200 *2 Carbon black A: manufactured by Tokai Carbon Co., Ltd., Seast 7HM, ISAF grade *3 Carbon black B: manufactured by Tokai Carbon Co., Ltd., Seast 3H, HAF grade *4 Anti-aging agent: manufactured by Ouchi Shinko Chemical Industry Co., Ltd., N -Phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD) *5 Vulcanization accelerator: Ouchi Shinko Chemical Industry Co., Ltd., N-cyclohexyl-2-benzothiazolylsulfenamide (Noxela CZ)
- the above rubber composition was prepared into a sheet-like sample with a size of 80 mm x 80 mm x 2 mm in thickness, and was vulcanized by irradiation with microwaves according to the following procedure.
- Example 1 a variable frequency microwave generator (manufactured by LAMBDA Technology, product name "VariWave (registered trademark)”) was used, and the values shown in Table 2 were set at each predetermined time interval shown in Table 2.
- the sheet-like sample was heated (vulcanized) by irradiation with the microwave while changing (increasing) the frequency of the microwave by a certain frequency change range shown in FIG. At that time, the sheet-like sample was sandwiched between plastic molds, the initial vulcanization pressure was set to 0.5 MPa, and the temperature of the sheet-like sample measured with an infrared thermometer was increased from about 30°C at a heating rate of 0.2°C/sec.
- the microwave irradiation output was PID-controlled so as to rise, and when it reached 140°C, it was held at that temperature for 30 minutes.
- the variable frequency microwave generator used has a variable frequency range of 5.8 to 6.6 GHz according to the device specifications. Therefore, the frequency of the microwave was increased each time, and when it reached 6.6 GHz, it was switched to 5.8 GHz, and thereafter, the frequency was restarted each time.
- Comparative Examples 1 to 3 the sheet-like samples were heated (vulcanized) by irradiation with microwaves at a fixed frequency (2.45 GHz) using a microwave synthesis reaction device "flexiWAVE" manufactured by Milestone General Co., Ltd. At that time, the initial vulcanization pressure and temperature control were the same as in the examples.
- the hardness is more than a predetermined value is based on the result that in the toluene immersion test of the sheet-like sample, if the hardness was more than the said predetermined value, it did not elute into toluene due to crosslinking.
- the vulcanized products obtained had high vulcanization uniformity by irradiating microwaves while sweeping the frequency in a predetermined manner.
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- Processes Of Treating Macromolecular Substances (AREA)
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Abstract
Provided is a vulcanization method capable of uniformly vulcanizing a rubber composition by microwave irradiation. The present invention is a vulcanization method for vulcanizing a rubber composition that contains a diene rubber and carbon black by irradiation with microwaves, said vulcanization method being characterized in that the frequency of the microwaves irradiating the rubber composition is changed by only a frequency width selected from the range of more than 0 Hz but not more than 1000 Hz each time a time interval selected from the range of more than 0 μsec but not more than 100 μsec elapses.
Description
本発明は、加硫方法に関するものである。
The present invention relates to a vulcanization method.
ゴム製品の製造にあたり、マイクロ波のエネルギーを利用することは知られている。例えば、特許文献1には、空気入りタイヤの製造において必要となる熱エネルギーの少なくとも一部にマイクロ波エネルギーを用いることで、全加熱時間を短縮し得ることが開示されている。
It is known that microwave energy is used in the production of rubber products. For example, Patent Document 1 discloses that the total heating time can be shortened by using microwave energy for at least part of the thermal energy required in manufacturing a pneumatic tire.
但し実際のところ、特許文献1においては、マイクロ波エネルギーによる加熱を加硫反応の開始前に終了している。この点に関し、従来、マイクロ波を照射して加硫反応を行った場合には、加硫反応のコントロールが極めて難しく、加硫が不均一となって局所的な焼き焦げが発生する等の問題があった。このような加硫不均一の問題などのため、現状、マイクロ波を用いたゴム加硫は完全な実用化に至っておらず、マイクロ波の利用は、せいぜい加硫前の予備加熱に留まっているという事情があった。
However, in fact, in Patent Document 1, heating by microwave energy is finished before the start of the vulcanization reaction. Regarding this point, conventionally, when the vulcanization reaction was performed by irradiating microwaves, it was extremely difficult to control the vulcanization reaction, and there were problems such as uneven vulcanization and local scorching. was there. Due to such problems of uneven vulcanization, rubber vulcanization using microwaves has not yet been fully put into practical use, and the use of microwaves is limited to preheating before vulcanization. There was a situation.
そこで、本発明は、マイクロ波の照射によってゴム組成物を均一に加硫することが可能な、加硫方法を提供することを目的とする。
Therefore, an object of the present invention is to provide a vulcanization method that can uniformly vulcanize a rubber composition by microwave irradiation.
本発明者らは、カーボンブラックがマイクロ波の吸収特性に優れた発熱体となり得る点に着目して、鋭意検討を重ねた。そして、カーボンブラックを含有するゴム組成物をマイクロ波照射によって加熱(加硫)する際、当該マイクロ波の周波数を所定の態様で掃引することにより、均一加硫が図れることを見出し、本発明をするに至った。
The present inventors focused on the fact that carbon black can serve as a heating element with excellent microwave absorption characteristics, and conducted extensive studies. They discovered that when heating (vulcanizing) a rubber composition containing carbon black by microwave irradiation, uniform vulcanization can be achieved by sweeping the frequency of the microwave in a predetermined manner. I ended up doing it.
即ち、上記目的を達成するための本発明の要旨構成は、以下の通りである。
That is, the gist of the present invention for achieving the above object is as follows.
[1]ジエン系ゴム及びカーボンブラックを含有するゴム組成物を、マイクロ波を照射することにより加硫する、加硫方法であって、
前記ゴム組成物に照射するマイクロ波の周波数を、0μsec超100μsec以下の範囲から選択される時間間隔の経過の毎に、0Hz超1000Hz以下の範囲から選択される周波数変化幅だけ周波数を変化させる、ことを特徴とする、加硫方法。 [1] A vulcanization method in which a rubber composition containing a diene rubber and carbon black is vulcanized by irradiation with microwaves,
The frequency of the microwave irradiated to the rubber composition is changed by a frequency change width selected from a range of more than 0 Hz and less than 1000 Hz every time a time interval selected from a range of more than 0 μsec and less than 100 μsec passes. A vulcanization method characterized by:
前記ゴム組成物に照射するマイクロ波の周波数を、0μsec超100μsec以下の範囲から選択される時間間隔の経過の毎に、0Hz超1000Hz以下の範囲から選択される周波数変化幅だけ周波数を変化させる、ことを特徴とする、加硫方法。 [1] A vulcanization method in which a rubber composition containing a diene rubber and carbon black is vulcanized by irradiation with microwaves,
The frequency of the microwave irradiated to the rubber composition is changed by a frequency change width selected from a range of more than 0 Hz and less than 1000 Hz every time a time interval selected from a range of more than 0 μsec and less than 100 μsec passes. A vulcanization method characterized by:
[2]前記時間間隔が、毎度一定である、[1]に記載の加硫方法。
[2] The vulcanization method according to [1], wherein the time interval is constant each time.
[3]前記周波数変化幅が、毎度一定である、[1]又は[2]に記載の加硫方法。
[3] The vulcanization method according to [1] or [2], wherein the frequency change width is constant each time.
本発明によれば、マイクロ波の照射によってゴム組成物を均一に加硫することが可能な、加硫方法を提供することができる。
According to the present invention, it is possible to provide a vulcanization method capable of uniformly vulcanizing a rubber composition by microwave irradiation.
以下に、本発明を、その実施形態に基づき、詳細に例示説明する。
Hereinafter, the present invention will be illustrated and explained in detail based on the embodiments thereof.
(加硫方法)
本発明の一実施形態の加硫方法は、ジエン系ゴム及びカーボンブラックを含有するゴム組成物を、マイクロ波を照射することにより加硫する、加硫方法であって、
前記ゴム組成物に照射するマイクロ波の周波数を、0μsec超100μsec以下の範囲から選択される時間間隔の経過の毎に、0Hz超1000Hz以下の範囲から選択される周波数変化幅だけ周波数を変化させる、ことを特徴とする。 (Vulcanization method)
A vulcanization method according to an embodiment of the present invention is a vulcanization method in which a rubber composition containing a diene rubber and carbon black is vulcanized by irradiating microwaves,
The frequency of the microwave irradiated to the rubber composition is changed by a frequency change width selected from a range of more than 0 Hz and less than 1000 Hz every time a time interval selected from a range of more than 0 μsec and less than 100 μsec passes. It is characterized by
本発明の一実施形態の加硫方法は、ジエン系ゴム及びカーボンブラックを含有するゴム組成物を、マイクロ波を照射することにより加硫する、加硫方法であって、
前記ゴム組成物に照射するマイクロ波の周波数を、0μsec超100μsec以下の範囲から選択される時間間隔の経過の毎に、0Hz超1000Hz以下の範囲から選択される周波数変化幅だけ周波数を変化させる、ことを特徴とする。 (Vulcanization method)
A vulcanization method according to an embodiment of the present invention is a vulcanization method in which a rubber composition containing a diene rubber and carbon black is vulcanized by irradiating microwaves,
The frequency of the microwave irradiated to the rubber composition is changed by a frequency change width selected from a range of more than 0 Hz and less than 1000 Hz every time a time interval selected from a range of more than 0 μsec and less than 100 μsec passes. It is characterized by
本明細書において、「マイクロ波」とは、周波数300MHz~300GHzの電磁波を指すものとする。
In this specification, "microwave" refers to electromagnetic waves with a frequency of 300 MHz to 300 GHz.
図1は、本実施形態の加硫方法に従った、ゴム組成物に照射するマイクロ波の周波数の掃引パターンを示す一例の概要図である。図1に示す掃引パターンでは、ゴム組成物に照射するマイクロ波の周波数を、一定の時間間隔(T)の経過の毎に、一定の周波数変化幅(F)だけ周波数を上昇させている。
FIG. 1 is a schematic diagram of an example showing a frequency sweep pattern of microwaves irradiated to a rubber composition according to the vulcanization method of the present embodiment. In the sweep pattern shown in FIG. 1, the frequency of the microwave irradiated to the rubber composition is increased by a constant frequency change width (F) every time a constant time interval (T) elapses.
本実施形態の加硫方法によりゴム組成物を均一に加硫できるメカニズムについて、本発明者らは以下のように考えている。
通常、カーボンブラックを含有するゴム組成物にマイクロ波を照射する場合には、ゴム組成物に直接照射されるマイクロ波と、マイクロ波発生装置内で少なくとも1回反射した後にゴム組成物に照射されるマイクロ波とにより、干渉作用が生じる。この点、例えばマイクロ波の周波数が一定であると、ゴム組成物において干渉作用が生じ易い箇所と生じ難い箇所とが固定的に偏在して、一部が過加熱、他の一部が加熱不足となる事態が生じ得る。かかる事態は、特に架橋反応が起こる120℃以上の温度で顕著となり、結果として加硫不均一を引き起こすものと考えられる。これに対し、本実施形態の加硫方法では、照射するマイクロ波の周波数を所定の態様で掃引するため、ゴム組成物におけるエネルギー吸収の局部集中化を効果的に回避できる結果、加熱(加硫)の均一化を図ることができるものと考えられる。 The present inventors believe that the mechanism by which the rubber composition can be uniformly vulcanized by the vulcanization method of this embodiment is as follows.
Normally, when a rubber composition containing carbon black is irradiated with microwaves, the rubber composition is directly irradiated with microwaves, and the rubber composition is irradiated with microwaves that are reflected at least once within a microwave generator. Interference effects occur due to the microwaves generated. In this respect, for example, if the frequency of microwaves is constant, areas where interference is likely to occur and areas where interference is unlikely to occur will be fixedly unevenly distributed in the rubber composition, resulting in overheating in some areas and underheating in other areas. A situation may arise where: This situation becomes particularly noticeable at temperatures of 120° C. or higher, where crosslinking reactions occur, and is thought to result in non-uniform vulcanization. In contrast, in the vulcanization method of the present embodiment, the frequency of the irradiated microwave is swept in a predetermined manner, so that local concentration of energy absorption in the rubber composition can be effectively avoided. ) is considered to be able to be made uniform.
通常、カーボンブラックを含有するゴム組成物にマイクロ波を照射する場合には、ゴム組成物に直接照射されるマイクロ波と、マイクロ波発生装置内で少なくとも1回反射した後にゴム組成物に照射されるマイクロ波とにより、干渉作用が生じる。この点、例えばマイクロ波の周波数が一定であると、ゴム組成物において干渉作用が生じ易い箇所と生じ難い箇所とが固定的に偏在して、一部が過加熱、他の一部が加熱不足となる事態が生じ得る。かかる事態は、特に架橋反応が起こる120℃以上の温度で顕著となり、結果として加硫不均一を引き起こすものと考えられる。これに対し、本実施形態の加硫方法では、照射するマイクロ波の周波数を所定の態様で掃引するため、ゴム組成物におけるエネルギー吸収の局部集中化を効果的に回避できる結果、加熱(加硫)の均一化を図ることができるものと考えられる。 The present inventors believe that the mechanism by which the rubber composition can be uniformly vulcanized by the vulcanization method of this embodiment is as follows.
Normally, when a rubber composition containing carbon black is irradiated with microwaves, the rubber composition is directly irradiated with microwaves, and the rubber composition is irradiated with microwaves that are reflected at least once within a microwave generator. Interference effects occur due to the microwaves generated. In this respect, for example, if the frequency of microwaves is constant, areas where interference is likely to occur and areas where interference is unlikely to occur will be fixedly unevenly distributed in the rubber composition, resulting in overheating in some areas and underheating in other areas. A situation may arise where: This situation becomes particularly noticeable at temperatures of 120° C. or higher, where crosslinking reactions occur, and is thought to result in non-uniform vulcanization. In contrast, in the vulcanization method of the present embodiment, the frequency of the irradiated microwave is swept in a predetermined manner, so that local concentration of energy absorption in the rubber composition can be effectively avoided. ) is considered to be able to be made uniform.
そのため、本実施形態の加硫方法では、(ターンテーブル式電子レンジのように、)加熱ムラの回避を目的として加熱対象物を装置内で移動又は回転させることは、必須ではない。
Therefore, in the vulcanization method of this embodiment, it is not essential to move or rotate the object to be heated within the apparatus for the purpose of avoiding uneven heating (as in a turntable microwave oven).
本実施形態の加硫方法では、周波数可変型マイクロ波発生装置(VFM、Variable Frequency Microwave)、特には、半導体発振器又は増幅器による周波数可変型マイクロ波発生装置を用いることができる。
In the vulcanization method of this embodiment, a variable frequency microwave generator (VFM), particularly a variable frequency microwave generator using a semiconductor oscillator or an amplifier, can be used.
本実施形態の加硫方法において、時間間隔(T)は、周波数を変化させるタイミング間の時間であり、言い換えれば、一定周波数のマイクロ波を照射する時間である。時間間隔(T)は、0μsec超100μsec以下の範囲から選択される。時間間隔(T)が100μsecを超えると、ゴム組成物の一部の箇所への熱の集中を十分に抑制できない虞がある。また、時間間隔(T)の下限としては、0μsec超であればよく、使用する装置の仕様によって適宜調整すればよい。特に、時間間隔(T)は、マイクロ波照射の効率の観点から、1μsec以上が好ましい。同様の観点から、時間間隔(T)は、3~50μsecの範囲から選択されることが好ましく、5~30μsecの範囲から選択されることがより好ましく、10~25μsecの範囲から選択されることが更に好ましい。
In the vulcanization method of this embodiment, the time interval (T) is the time between timings at which the frequency is changed, or in other words, the time at which microwaves of a constant frequency are irradiated. The time interval (T) is selected from a range of more than 0 μsec and less than 100 μsec. If the time interval (T) exceeds 100 μsec, there is a possibility that concentration of heat in some parts of the rubber composition cannot be sufficiently suppressed. Further, the lower limit of the time interval (T) may be more than 0 μsec, and may be adjusted as appropriate depending on the specifications of the device used. In particular, the time interval (T) is preferably 1 μsec or more from the viewpoint of efficiency of microwave irradiation. From the same viewpoint, the time interval (T) is preferably selected from the range of 3 to 50 μsec, more preferably selected from the range of 5 to 30 μsec, and more preferably selected from the range of 10 to 25 μsec. More preferred.
時間間隔(T)は、上述したメカニズムに鑑みれば、図1に示すように毎度一定であってもよく、或いは、都度異なってもよい。但し、本実施形態の加硫方法では、より効果的に加硫の均一化を図る観点から、時間間隔(T)が毎度一定であることが好ましい。
In view of the mechanism described above, the time interval (T) may be constant each time as shown in FIG. 1, or may be different each time. However, in the vulcanization method of this embodiment, it is preferable that the time interval (T) is constant each time from the viewpoint of achieving uniform vulcanization more effectively.
また、周波数変化幅(F)は、0Hz超1000Hz以下の範囲から選択される。周波数が全く変化しないと(周波数変化幅(F)が0Hzであると)、ゴム組成物の一部の箇所への熱が集中することとなる。また、周波数変化幅(F)が1000Hzを超えると、マイクロ波照射の安定性が悪化し、均一加硫に悪影響を及ぼす虞がある。同様の観点から、周波数変化幅(F)は、10~500Hzの範囲から選択されることが好ましく、50~350Hzの範囲から選択されることがより好ましく、100~260Hzの範囲から選択されることが更に好ましい。
Further, the frequency change width (F) is selected from a range of more than 0 Hz and less than 1000 Hz. If the frequency does not change at all (if the frequency change width (F) is 0 Hz), heat will be concentrated in some parts of the rubber composition. Furthermore, if the frequency change width (F) exceeds 1000 Hz, the stability of microwave irradiation may deteriorate, which may adversely affect uniform vulcanization. From the same viewpoint, the frequency change width (F) is preferably selected from the range of 10 to 500 Hz, more preferably selected from the range of 50 to 350 Hz, and preferably selected from the range of 100 to 260 Hz. is even more preferable.
周波数変化幅(F)は、上述したメカニズムに鑑みれば、図1に示すように毎度一定であってもよく、或いは、都度異なってもよい。但し、本実施形態の加硫方法では、より効果的に加硫の均一化を図る観点から、周波数変化幅(F)が毎度一定であることが好ましい。
In view of the above-mentioned mechanism, the frequency change width (F) may be constant each time as shown in FIG. 1, or may be different each time. However, in the vulcanization method of this embodiment, from the viewpoint of more effectively achieving uniform vulcanization, it is preferable that the frequency change width (F) is constant each time.
また、周波数変化幅(F)分の周波数の変化のさせ方は、上述したメカニズムに鑑みれば、図1に示すように毎度上昇であってもよく、或いは、毎度低下であってもよく、或いは、上昇又は低下が都度異なってもよい。但し、本実施形態の加硫方法では、毎度、周波数変化幅(F)だけ周波数を上昇させることが好ましい。
Further, in view of the above-mentioned mechanism, the frequency change by the frequency change width (F) may be increased every time as shown in FIG. 1, or may be decreased every time. , the increase or decrease may be different each time. However, in the vulcanization method of this embodiment, it is preferable to increase the frequency by the frequency change width (F) each time.
なお、周波数可変型マイクロ波発生装置は、通常、装置仕様上の可変周波数の上限及び下限がある。そのため、そのような周波数可変型マイクロ波発生装置を用い、周波数を毎度上昇させると、周波数が可変周波数の上限又はその付近に達する場合がある。この場合には、一旦、周波数を可変周波数の下限又はその付近に切り替えた後、周波数の毎度の上昇を再開すればよい。周波数を毎度低下させるときも、同様のやり方とすればよい。
Note that variable frequency microwave generators usually have upper and lower limits of variable frequency based on the device specifications. Therefore, if such a variable frequency microwave generator is used and the frequency is increased each time, the frequency may reach or be close to the upper limit of the variable frequency. In this case, once the frequency is switched to the lower limit of the variable frequency or around it, the frequency may be increased again each time. A similar method may be used when lowering the frequency each time.
本実施形態の加硫方法における、マイクロ波の周波数の使用帯域は、特に限定されず、例えば、用いるマイクロ波発生装置の仕様(特には、発振器又は増幅器の種類)に基づいて適宜選択することができる。
In the vulcanization method of the present embodiment, the frequency range of the microwave is not particularly limited, and may be selected as appropriate based on the specifications of the microwave generator used (in particular, the type of oscillator or amplifier). can.
本実施形態の加硫方法では、特に限定されないが、周波数を所定の態様で掃引しながらマイクロ波を照射する操作の継続時間が、100秒以上であることが好ましく、200秒以上であることがより好ましく、300秒以上であることが更に好ましい。この場合、ゴム組成物の加硫の度合いをより十分に高めることができる。
In the vulcanization method of this embodiment, the duration of the operation of irradiating microwaves while sweeping the frequency in a predetermined manner is preferably 100 seconds or more, and preferably 200 seconds or more, although it is not particularly limited. More preferably, the time is 300 seconds or more. In this case, the degree of vulcanization of the rubber composition can be more fully increased.
本実施形態の加硫方法では、特に限定されないが、周波数を所定の態様で掃引しながらマイクロ波を照射する際に、ゴム組成物の温度をモニタリングしてもよい。ゴム組成物の温度をモニタリングすることで、より確実に、均一加硫を図ることができる。更に、本実施形態の加硫方法では、マイクロ波を照射する際に、ゴム組成物の昇温速度をコントロールしてもよい。その場合、昇温速度のコントロールは、例えば、マイクロ波の照射出力(W)の微調整により行うことができる。また、昇温速度のコントロール方式は、特に限定されないが、PID制御とすることができる。或いは、昇温速度のコントロールは、マイクロ波照射のオン-オフ切り替えにより行うこともできる。そして、昇温速度は、例えば、0.05℃/秒以上0.5℃/秒以下の範囲から選択することができる。
In the vulcanization method of the present embodiment, although not particularly limited, the temperature of the rubber composition may be monitored during irradiation with microwaves while sweeping the frequency in a predetermined manner. By monitoring the temperature of the rubber composition, uniform vulcanization can be achieved more reliably. Furthermore, in the vulcanization method of this embodiment, the rate of temperature increase of the rubber composition may be controlled when irradiating with microwaves. In that case, the temperature increase rate can be controlled, for example, by finely adjusting the microwave irradiation output (W). Further, the control method for the temperature increase rate is not particularly limited, but may be PID control. Alternatively, the temperature increase rate can also be controlled by switching on/off the microwave irradiation. The temperature increase rate can be selected, for example, from a range of 0.05° C./second to 0.5° C./second.
本実施形態の加硫方法において、実際にゴム組成物を加硫する際の最高到達温度(いわゆる加硫温度)は、特に限定されず、目的に応じて適宜選択することができるが、通常は140℃以上とすることが好ましく、また、190℃以下とすることが好ましく、160℃以下とすることがより好ましい。
In the vulcanization method of the present embodiment, the highest temperature reached when actually vulcanizing the rubber composition (so-called vulcanization temperature) is not particularly limited and can be appropriately selected depending on the purpose, but usually The temperature is preferably 140°C or higher, preferably 190°C or lower, and more preferably 160°C or lower.
<加硫対象のゴム組成物>
本実施形態の加硫方法で用いる、加硫対象のゴム組成物は、少なくともジエン系ゴム及びカーボンブラックを含有する。また、加硫対象のゴム組成物は、更に必要に応じて、加硫剤、その他の成分などを適宜含有することができる。 <Rubber composition to be vulcanized>
The rubber composition to be vulcanized used in the vulcanization method of this embodiment contains at least diene rubber and carbon black. Further, the rubber composition to be vulcanized may further contain a vulcanizing agent, other components, etc. as necessary.
本実施形態の加硫方法で用いる、加硫対象のゴム組成物は、少なくともジエン系ゴム及びカーボンブラックを含有する。また、加硫対象のゴム組成物は、更に必要に応じて、加硫剤、その他の成分などを適宜含有することができる。 <Rubber composition to be vulcanized>
The rubber composition to be vulcanized used in the vulcanization method of this embodiment contains at least diene rubber and carbon black. Further, the rubber composition to be vulcanized may further contain a vulcanizing agent, other components, etc. as necessary.
ジエン系ゴムとしては、例えば、天然ゴム(NR)、ブタジエンゴム(BR)、イソプレンゴム(IR)、スチレン-ブタジエンゴム(SBR)、エチレン-プロピレン-ジエンゴム(EPDM)、クロロプレンゴム(CR)、ハロゲン化ブチルゴム、アクリロニリトル-ブタジエンゴム(NBR)等が挙げられる。これらジエン系ゴムは、1種単独で用いてもよく、2種以上を組み合わせて用いてもよい。これらの中でも、本発明の加硫方法による加硫均一化の効果をより確実に享受する観点から、ジエン系ゴムとしては、天然ゴム、ブタジエンゴム、イソプレンゴム及びスチレン-ブタジエンゴムの少なくともいずれかを用いることが好ましい。
Examples of diene rubber include natural rubber (NR), butadiene rubber (BR), isoprene rubber (IR), styrene-butadiene rubber (SBR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), and halogen rubber. butyl rubber, acrylonitributylene butadiene rubber (NBR), and the like. These diene rubbers may be used alone or in combination of two or more. Among these, from the viewpoint of more reliably enjoying the effect of uniform vulcanization by the vulcanization method of the present invention, at least one of natural rubber, butadiene rubber, isoprene rubber, and styrene-butadiene rubber is used as the diene rubber. It is preferable to use
カーボンブラックとしては、例えば、GPF、FEF、HAF、ISAF、SAFのグレードのカーボンブラックが挙げられる。これらカーボンブラックは、1種単独で用いてもよく、2種以上を組み合わせて用いてもよい。
Examples of carbon black include GPF, FEF, HAF, ISAF, and SAF grade carbon black. These carbon blacks may be used alone or in combination of two or more.
ゴム組成物におけるカーボンブラックの含有量としては、特に限定されず、目的に応じて適宜選択することができるが、本発明の加硫方法による加硫均一化の効果をより確実に享受する観点から、ジエン系ゴム100質量部に対して10質量部以上であることが好ましく、30質量部以上であることがより好ましい。また、ゴム組成物におけるカーボンブラックの含有量は、得られる加硫ゴム組成物の機械特性を保持する観点から、ジエン系ゴム100質量部に対して120質量部以下であることが好ましく、70質量部以下であることがより好ましい。
The content of carbon black in the rubber composition is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of more reliably enjoying the effect of uniform vulcanization by the vulcanization method of the present invention. , preferably 10 parts by mass or more, more preferably 30 parts by mass or more, based on 100 parts by mass of diene rubber. Further, from the viewpoint of maintaining the mechanical properties of the resulting vulcanized rubber composition, the content of carbon black in the rubber composition is preferably 120 parts by mass or less, and 70 parts by mass or less, based on 100 parts by mass of diene rubber. It is more preferable that the amount is less than 1 part.
ゴム組成物は、加硫剤を含有することが好ましい。加硫剤としては、例えば、硫黄、モルホリンジスルフィド等の硫黄系加硫剤;ベンゾイルパーオキサイド、ジクミルパーオキサイド、ジ-t-ブチルパーオキサイド、t-ブチルクミルパーオキサイド、メチルエチルケトンパーオキサイド、クメンハイドロパーオキサイド、2,5-ジメチル-2,5-ジ(t-ブチルパーオキシ)ヘキサン等の有機過酸化物;等が挙げられる。また、加硫剤としては、ヘキサメチレンビスチオサルフェート2ナトリウム塩2水和物、1,3-ビス(シトラコンイミドメチル)ベンゼン、4,4’-ジフェニルメタンビスマレイミド、m-フェニレンビスマレイミド等も挙げられる。これら加硫剤は、1種単独で用いてもよく、2種以上を組み合わせて用いてもよい。
It is preferable that the rubber composition contains a vulcanizing agent. Examples of the vulcanizing agent include sulfur and sulfur-based vulcanizing agents such as morpholine disulfide; benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, methyl ethyl ketone peroxide, cumene hydro Peroxide, organic peroxides such as 2,5-dimethyl-2,5-di(t-butylperoxy)hexane; and the like. Examples of the vulcanizing agent include hexamethylene bisthiosulfate disodium salt dihydrate, 1,3-bis(citraconimidomethyl)benzene, 4,4'-diphenylmethane bismaleimide, m-phenylene bismaleimide, etc. It will be done. These vulcanizing agents may be used alone or in combination of two or more.
ゴム組成物における加硫剤の含有量としては、特に限定されず、目的に応じて適宜選択することができ、例えば、ジエン系ゴム100質量部に対して0.1質量部以上10質量部以下とすることができる。
The content of the vulcanizing agent in the rubber composition is not particularly limited and can be appropriately selected depending on the purpose, for example, 0.1 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of diene rubber. It can be done.
その他の成分としては、カーボンブラック以外の充填剤(シリカなど)、ステアリン酸等の加硫助剤、加硫促進剤、亜鉛華等の加硫促進助剤、老化防止剤、軟化剤、可塑剤、加工性改良剤などが挙げられ、これらを適量含有することができる。
Other ingredients include fillers other than carbon black (such as silica), vulcanization aids such as stearic acid, vulcanization accelerators, vulcanization accelerators such as zinc white, anti-aging agents, softeners, and plasticizers. , processability improvers, etc., and these can be contained in appropriate amounts.
加硫対象のゴム組成物は、例えば、ロール、インターナルミキサー、バンバリーローター等の混練機を用い、常法に従って上述した各成分を配合して混練することにより得られたものとすることができる。
The rubber composition to be vulcanized can be obtained by blending and kneading the above-mentioned components according to a conventional method using a kneading machine such as a roll, an internal mixer, or a Banbury rotor. .
加硫対象のゴム組成物の形状としては、特に限定されない。例えば、加硫対象のゴム組成物は、あらかじめ成形してなるプレ成形体とすることができ、特には、従来は不均一加熱が起こりやすかった複雑な形状のプレ成形体であっても、均一に加硫することができ、ひいては所望の加硫成形体を得ることができる。
The shape of the rubber composition to be vulcanized is not particularly limited. For example, the rubber composition to be vulcanized can be made into a pre-molded body, and in particular, even if it is a pre-molded body with a complicated shape, which conventionally was prone to non-uniform heating, it can be uniformly heated. The vulcanized product can be vulcanized to give a desired vulcanized molded product.
なお、加硫対象のゴム組成物中に、金属部品が含まれていてもよい。本実施形態の加硫方法では、上述の通り、照射するマイクロ波の周波数の掃引態様の適正化が図られているので、金属部品におけるアーキング等の不具合の抑制が期待される。
Note that metal parts may be included in the rubber composition to be vulcanized. In the vulcanization method of the present embodiment, as described above, since the sweep mode of the frequency of the irradiated microwave is optimized, it is expected that problems such as arcing in metal parts can be suppressed.
以下に、実施例を挙げて本発明を更に詳しく説明するが、本発明は下記の実施例に何ら限定されるものではない。
The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to the Examples below.
<ゴム組成物の調製>
表1に示す配合処方で常法に従って混練して、ゴム組成物を調製した。 <Preparation of rubber composition>
A rubber composition was prepared by kneading according to a conventional method using the formulation shown in Table 1.
表1に示す配合処方で常法に従って混練して、ゴム組成物を調製した。 <Preparation of rubber composition>
A rubber composition was prepared by kneading according to a conventional method using the formulation shown in Table 1.
*1 イソプレンゴム:JSR株式会社製、IR2200
*2 カーボンブラックA:東海カーボン株式会社製、シースト7HM、ISAFグレード
*3 カーボンブラックB:東海カーボン株式会社製、シースト3H、HAFグレード
*4 老化防止剤:大内新興化学工業株式会社製、N-フェニル-N’-(1,3-ジメチルブチル)-p-フェニレンジアミン(6PPD)
*5 加硫促進剤:大内新興化学工業株式会社製、N-シクロヘキシル-2-ベンゾチアゾリルスルフェンアミド(ノクセラーCZ) *1 Isoprene rubber: JSR Corporation, IR2200
*2 Carbon black A: manufactured by Tokai Carbon Co., Ltd., Seast 7HM, ISAF grade *3 Carbon black B: manufactured by Tokai Carbon Co., Ltd., Seast 3H, HAF grade *4 Anti-aging agent: manufactured by Ouchi Shinko Chemical Industry Co., Ltd., N -Phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD)
*5 Vulcanization accelerator: Ouchi Shinko Chemical Industry Co., Ltd., N-cyclohexyl-2-benzothiazolylsulfenamide (Noxela CZ)
*2 カーボンブラックA:東海カーボン株式会社製、シースト7HM、ISAFグレード
*3 カーボンブラックB:東海カーボン株式会社製、シースト3H、HAFグレード
*4 老化防止剤:大内新興化学工業株式会社製、N-フェニル-N’-(1,3-ジメチルブチル)-p-フェニレンジアミン(6PPD)
*5 加硫促進剤:大内新興化学工業株式会社製、N-シクロヘキシル-2-ベンゾチアゾリルスルフェンアミド(ノクセラーCZ) *1 Isoprene rubber: JSR Corporation, IR2200
*2 Carbon black A: manufactured by Tokai Carbon Co., Ltd., Seast 7HM, ISAF grade *3 Carbon black B: manufactured by Tokai Carbon Co., Ltd., Seast 3H, HAF grade *4 Anti-aging agent: manufactured by Ouchi Shinko Chemical Industry Co., Ltd., N -Phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD)
*5 Vulcanization accelerator: Ouchi Shinko Chemical Industry Co., Ltd., N-cyclohexyl-2-benzothiazolylsulfenamide (Noxela CZ)
<ゴム組成物の加硫>
上記のゴム組成物について、80mm×80mm×厚み2mmのサイズのシート状サンプルとし、下記の手順に従ってマイクロ波を照射して加硫した。 <Vulcanization of rubber composition>
The above rubber composition was prepared into a sheet-like sample with a size of 80 mm x 80 mm x 2 mm in thickness, and was vulcanized by irradiation with microwaves according to the following procedure.
上記のゴム組成物について、80mm×80mm×厚み2mmのサイズのシート状サンプルとし、下記の手順に従ってマイクロ波を照射して加硫した。 <Vulcanization of rubber composition>
The above rubber composition was prepared into a sheet-like sample with a size of 80 mm x 80 mm x 2 mm in thickness, and was vulcanized by irradiation with microwaves according to the following procedure.
実施例1~3では、周波数可変型マイクロ波発生装置(LAMBDA Technology社製、製品名「VariWave(登録商標)」)を用い、表2に示す一定の時間間隔の経過の毎に、表2に示す一定の周波数変化幅だけマイクロ波の周波数を変化させながら(上昇させながら)、当該マイクロ波の照射によりシート状サンプルを加熱(加硫)した。その際、シート状サンプルをプラスチックモールドに挟み、初期加硫圧を0.5MPaとし、赤外線温度計で測定されるシート状サンプルの温度が約30℃から0.2℃/秒の昇温速度で上昇するようにマイクロ波の照射出力をPID制御し、140℃に到達したら、当該温度で30分保持した。
なお、使用した周波数可変型マイクロ波発生装置は、装置仕様上の可変周波数の範囲が5.8~6.6GHzである。そのため、マイクロ波の周波数を毎度上昇させて6.6GHzに達したときには、5.8GHzに切り替え、その後、毎度の上昇を再開した。 In Examples 1 to 3, a variable frequency microwave generator (manufactured by LAMBDA Technology, product name "VariWave (registered trademark)") was used, and the values shown in Table 2 were set at each predetermined time interval shown in Table 2. The sheet-like sample was heated (vulcanized) by irradiation with the microwave while changing (increasing) the frequency of the microwave by a certain frequency change range shown in FIG. At that time, the sheet-like sample was sandwiched between plastic molds, the initial vulcanization pressure was set to 0.5 MPa, and the temperature of the sheet-like sample measured with an infrared thermometer was increased from about 30°C at a heating rate of 0.2°C/sec. The microwave irradiation output was PID-controlled so as to rise, and when it reached 140°C, it was held at that temperature for 30 minutes.
The variable frequency microwave generator used has a variable frequency range of 5.8 to 6.6 GHz according to the device specifications. Therefore, the frequency of the microwave was increased each time, and when it reached 6.6 GHz, it was switched to 5.8 GHz, and thereafter, the frequency was restarted each time.
なお、使用した周波数可変型マイクロ波発生装置は、装置仕様上の可変周波数の範囲が5.8~6.6GHzである。そのため、マイクロ波の周波数を毎度上昇させて6.6GHzに達したときには、5.8GHzに切り替え、その後、毎度の上昇を再開した。 In Examples 1 to 3, a variable frequency microwave generator (manufactured by LAMBDA Technology, product name "VariWave (registered trademark)") was used, and the values shown in Table 2 were set at each predetermined time interval shown in Table 2. The sheet-like sample was heated (vulcanized) by irradiation with the microwave while changing (increasing) the frequency of the microwave by a certain frequency change range shown in FIG. At that time, the sheet-like sample was sandwiched between plastic molds, the initial vulcanization pressure was set to 0.5 MPa, and the temperature of the sheet-like sample measured with an infrared thermometer was increased from about 30°C at a heating rate of 0.2°C/sec. The microwave irradiation output was PID-controlled so as to rise, and when it reached 140°C, it was held at that temperature for 30 minutes.
The variable frequency microwave generator used has a variable frequency range of 5.8 to 6.6 GHz according to the device specifications. Therefore, the frequency of the microwave was increased each time, and when it reached 6.6 GHz, it was switched to 5.8 GHz, and thereafter, the frequency was restarted each time.
比較例1~3では、マイルストーンゼネラル株式会社のマイクロ波合成反応装置、「flexiWAVE」を用い、固定周波数(2.45GHz)のマイクロ波の照射により、シート状サンプルを加熱(加硫)した。その際、初期加硫圧及び温度制御は、実施例と同様とした。
In Comparative Examples 1 to 3, the sheet-like samples were heated (vulcanized) by irradiation with microwaves at a fixed frequency (2.45 GHz) using a microwave synthesis reaction device "flexiWAVE" manufactured by Milestone General Co., Ltd. At that time, the initial vulcanization pressure and temperature control were the same as in the examples.
加硫後の各シート状サンプルについて、1cm間隔、計36点における硬度を、高分子計器株式会社デジタルハードネステスターRH 101aを用いて測定した。そして、全測定点(36点)のうち、硬度が以下に示す所定値以上である測定点の割合(%)を算出した。
カーボンブラックA(ISAF)配合量25部・・・硬度50
カーボンブラックA(ISAF)配合量50部・・・硬度60
カーボンブラックB(HAF)配合量50部・・・硬度60
結果を「加硫均一性」として表2に示す。かかる割合が大きいほど、加硫均一性が高いことを示す。なお、「硬度が所定値以上」は、シート状サンプルのトルエン浸漬試験において、硬度当該所定値以上であれば、架橋によりトルエンに溶出しなかったという結果に基づくものである。 For each sheet sample after vulcanization, the hardness at 36 points in total at 1 cm intervals was measured using Kobunshi Keiki Co., Ltd. Digital Hardness Tester RH 101a. Then, among all the measurement points (36 points), the ratio (%) of measurement points whose hardness was equal to or higher than a predetermined value shown below was calculated.
Carbon black A (ISAF) blending amount: 25 parts...Hardness: 50
Carbon black A (ISAF) blending amount: 50 parts...Hardness: 60
Carbon black B (HAF) blending amount: 50 parts...Hardness: 60
The results are shown in Table 2 as "vulcanization uniformity". The larger this ratio is, the higher the vulcanization uniformity is. In addition, "the hardness is more than a predetermined value" is based on the result that in the toluene immersion test of the sheet-like sample, if the hardness was more than the said predetermined value, it did not elute into toluene due to crosslinking.
カーボンブラックA(ISAF)配合量25部・・・硬度50
カーボンブラックA(ISAF)配合量50部・・・硬度60
カーボンブラックB(HAF)配合量50部・・・硬度60
結果を「加硫均一性」として表2に示す。かかる割合が大きいほど、加硫均一性が高いことを示す。なお、「硬度が所定値以上」は、シート状サンプルのトルエン浸漬試験において、硬度当該所定値以上であれば、架橋によりトルエンに溶出しなかったという結果に基づくものである。 For each sheet sample after vulcanization, the hardness at 36 points in total at 1 cm intervals was measured using Kobunshi Keiki Co., Ltd. Digital Hardness Tester RH 101a. Then, among all the measurement points (36 points), the ratio (%) of measurement points whose hardness was equal to or higher than a predetermined value shown below was calculated.
Carbon black A (ISAF) blending amount: 25 parts...Hardness: 50
Carbon black A (ISAF) blending amount: 50 parts...Hardness: 60
Carbon black B (HAF) blending amount: 50 parts...Hardness: 60
The results are shown in Table 2 as "vulcanization uniformity". The larger this ratio is, the higher the vulcanization uniformity is. In addition, "the hardness is more than a predetermined value" is based on the result that in the toluene immersion test of the sheet-like sample, if the hardness was more than the said predetermined value, it did not elute into toluene due to crosslinking.
表2より、実施例においては、周波数を所定の態様で掃引しながらマイクロ波を照射したことで、得られた加硫物の加硫均一性が高いことが分かる。
From Table 2, it can be seen that in the examples, the vulcanized products obtained had high vulcanization uniformity by irradiating microwaves while sweeping the frequency in a predetermined manner.
本発明によれば、マイクロ波の照射によってゴム組成物を均一に加硫することが可能な、加硫方法を提供することができる。
According to the present invention, it is possible to provide a vulcanization method that enables uniform vulcanization of a rubber composition by microwave irradiation.
Claims (3)
- ジエン系ゴム及びカーボンブラックを含有するゴム組成物を、マイクロ波を照射することにより加硫する、加硫方法であって、
前記ゴム組成物に照射するマイクロ波の周波数を、0μsec超100μsec以下の範囲から選択される時間間隔の経過の毎に、0Hz超1000Hz以下の範囲から選択される周波数変化幅だけ周波数を変化させる、ことを特徴とする、加硫方法。 A vulcanization method in which a rubber composition containing a diene rubber and carbon black is vulcanized by irradiating it with microwaves, the method comprising:
The frequency of the microwave irradiated to the rubber composition is changed by a frequency change width selected from a range of more than 0 Hz and less than 1000 Hz every time a time interval selected from a range of more than 0 μsec and less than 100 μsec passes. A vulcanization method characterized by: - 前記時間間隔が、毎度一定である、請求項1に記載の加硫方法。 The vulcanization method according to claim 1, wherein the time interval is constant each time.
- 前記周波数変化幅が、毎度一定である、請求項1又は2に記載の加硫方法。
The vulcanization method according to claim 1 or 2, wherein the frequency change width is constant each time.
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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JPS63295638A (en) * | 1987-05-27 | 1988-12-02 | Kawasaki Steel Corp | Vulcanization of rubber |
US5721286A (en) * | 1991-11-14 | 1998-02-24 | Lockheed Martin Energy Systems, Inc. | Method for curing polymers using variable-frequency microwave heating |
JP2021195544A (en) * | 2020-06-12 | 2021-12-27 | 株式会社ブリヂストン | Vulcanization method and vulcanized rubber composition for tire |
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Publication number | Priority date | Publication date | Assignee | Title |
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JPS63295638A (en) * | 1987-05-27 | 1988-12-02 | Kawasaki Steel Corp | Vulcanization of rubber |
US5721286A (en) * | 1991-11-14 | 1998-02-24 | Lockheed Martin Energy Systems, Inc. | Method for curing polymers using variable-frequency microwave heating |
JP2021195544A (en) * | 2020-06-12 | 2021-12-27 | 株式会社ブリヂストン | Vulcanization method and vulcanized rubber composition for tire |
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