CA1340497C - Vulcanizate activator system for rubber compositions - Google Patents
Vulcanizate activator system for rubber compositionsInfo
- Publication number
- CA1340497C CA1340497C CA000609570A CA609570A CA1340497C CA 1340497 C CA1340497 C CA 1340497C CA 000609570 A CA000609570 A CA 000609570A CA 609570 A CA609570 A CA 609570A CA 1340497 C CA1340497 C CA 1340497C
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- Prior art keywords
- sulfur
- rubber
- phr
- group
- copolymer
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
- C08C19/00—Chemical modification of rubber
Abstract
A method is disclosed for increasing the rate of vulcanization of a rubber composition comprising adding to a sulfur vulcanizable rubber a methyl trialkyl ammonium salt of the formula:
(see fig. I) wherein R1, R2, and R3 are independently alkyl radicals having 8 to 10 carbon atoms and M is selected from the group consisting of Cl, Br, CH3SO4 and HSO4. Addition of a methyl trialkyl ammonium salt of the above formula significantly increases the rate of vulcanization of the rubber.
(see fig. I) wherein R1, R2, and R3 are independently alkyl radicals having 8 to 10 carbon atoms and M is selected from the group consisting of Cl, Br, CH3SO4 and HSO4. Addition of a methyl trialkyl ammonium salt of the above formula significantly increases the rate of vulcanization of the rubber.
Description
W LCANIZATE ACTIVATOR SYSTEM FOR RUBBER COMPOSITIONS
Field of the Invention The present invention relates to the vulcanization of a sulfur curable rubber composition.
More particularly, the present invention relates to a method for increasing the rate of cure of a sulfur w lcanizable rubber by the addition of a methyl trialkyl ~mmon;um salt.
Background of the Invention The "rate of cure" is defined as the rate at which crosslinking and the development of the stiffness (modulus) of a rubber compound occurs. As the rubber compound is heated, the properties of the rubber compound change from a soft plastic to a tough elastic material. During the curing step, crosslinks are introduced, which connect the long polymer chains of the rubber. As more crosslinks are introduced, the polymer chains become more firmly connected and the stiffness or modulus of the compound increases. The rate of cure is an important vulcanization parameter since it in part determines the time the compound must be cured, i.e., the "cure time". In the manufacture of vulcanized rubber articles, significant cost savings can be realized through a reduction of cure time. Through enhanced rates of cure, the cure time required to meet m;n;mllm states of cure can be reduced. Given the above, extensive research has been conducted in order to shorten the cure times of rubbers. Therefore, there exists a need for improved methods which enhance 134~497 the rate of cure in the absence of imparting undesirable properties to the vulcanizate.
Summary of the Invention The present invention relates to a method for enhancing the rate of vulcanization of a rubber composition comprising adding to a sulfur vulcanizable rubber a methyl trialkyl ammonium salt of the formula:
R2 (3 wherein R1, R2, and R3 are independently alkyl radicals having 8 to 10 carbon atoms and M is selected from the group consisting of Cl, Br, CH3SO4 and HSO4. In addition, there is disclosed a sulfur w lcanizable rubber composition comprising an elastomer containing olefinic unsaturation, a sulfur vulcanizing agent, an accelerator and a methyl trialkyl am~monium salt selected from the above formula.
Detailed Description of the Invention The present invention relates to the use of a methyl trialkyl ammonium salt as an activator for sulfur curable rubber compositions. A particularly preferred methyl trialkyl am.monium salt is methyl trialkyl(C8-C10) ~mmo~;um chloride which is commercially available under the trademark Adogen~ 464 from Sherex Chemical Company of Dublin, Ohio and from Henkel Corporation, Minneapolis, Minnesota, under the trademark Aliquot~ 336. Methyl trialkyl ammonium salts are generally known as phase-transfer catalysts and are described in U.S. Patent 3,992,432.
134~49 7 For ease in handling, the methyl trialkyl ammonium salt may be deposited on suitable carriers. Examples of carriers which may be used in the present invention include silica, carbon black, alumina, kieselguhr, silica gel and calcium silicate.
Use of a methyl trialkyl ammonium salt does not appear to affect crosslink distribution when used in combination with primary and optionally secondary accelerators. However, along with increased cure rate, there is usually seen an increased curative efficiency in the form of increased state or degree of cure.
The present invention may be used to cure sulfur vulcanizable rubbers or elastomers containing olefinic unsaturation. The phrase "rubber or elastomer containing olefinic unsaturation" is intended to include both natural rubber and its various raw and reclaim forms as well as various synthetic rubbers.
Representative synthetic polymers are the homopolymerization products of butadiene and its homologues and derivatives, for example, methylbutadiene, dimethylbutadiene and pentadiene as well as copolymers such as those formed from butadiene or its homologues or derivatives with other unsaturated monomers. Among the latter are acetylenes, for example, vinyl acetylene; olefins, for example, isobutylene, which copolymerizes with isoprene to form butyl rubber; vinyl compounds, for example, acrylic acid, acrylonitrile (which polymerize with butadiene to form NBR), methacrylic acid and styrene, the latter compound polymerizing with butadiene to form SBR, as well as vinyl esters and various unsaturated aldehydes, ketones and ethers, e.g., acrolein, methyl isopropenyl ketone and vinylethyl ether. Specific examples of synthetic rubbers include neoprene (polychloroprene), '~h polybutadiene (including cis-1,4-polybutadiene), polyisoprene (including cis-1,4-polyisoprene), butyl rubber, copolymers of 1,3-butadiene or isoprene with monomers such as styrene, acrylonitrile and methyl methacrylate, as well as ethylene/propylene terpolymers, also known as ethylene/propylene/diene monomer (EPDM), and in particular, ethylene/propylene/
dicyclopentadiene terpolymers.
The activator used in the present invention may be added to the rubber by any conventional technique such as on a mill or in a Banbury. The amount of methyl trialkyl ammonium salt may vary widely depending on the type of rubber and other compounds present in the vulcanizable composition. Generally, the amount of methyl trialkyl ammonium salt is used in a range of from about .05 to about 5.0 phr with a range of .1 to about 1.5 phr being preferred.
Vulcanization of the rubber is generally carried out at temperatures of between about 100~C and 200~C.
Preferably, the vulcanization is conducted at temperatures ranging from about 110~C to 180~C. Any of the usual vulcanization processes may be used such as heating in a press or mold, heating with superheated steam or hot air or in a salt bath.
In addition to the methyl trialkyl ammonium salt, other rubber additives may also be incorporated in the sulfur vulcanizable material. The additives commonly used in rubber vulcanizates are, for example, carbon black, tackifier resins, processing aids, antioxidants, antiozonants, stearic acid, activators, waxes, oils and peptizing agents. As known to those skilled in the art, depending on the intended use of the sulfur vulcanizable material, certain additives mentioned above are commonly used in conventional amounts.
134~497 Typical additions of carbon black comprise about 20 to 100 parts by weight of diene rubber (phr), preferably 50 to 70 phr. Typical amounts of tackifier resins comprise about 5 to 10 phr. Typical amounts of processing aids comprise about 1 to 5 phr. Typical amounts of antioxidants comprise 1 to about 10 phr.
Typical amounts of antiozonants comprise 1 to about 10 phr. Typical amounts of stearic acid comprise 1 to about 2 phr. Typical amounts of zinc oxide comprise 2 to 5 phr. Typical amounts of waxes comprise 1 to 5 phr. Typical amounts of oils comprise 5 to 30 phr.
Typical amounts of peptizers comprise .l to 1 phr. The presence and relative amounts of the above additives are not an aspect of the present invention.
The vulcanization is conducted in the presence of a sulfur vulcanizing agent. Examples of suitable sulfur vulcanizing agents include elemental sulfur (free sulfur) or sulfur donating vulcanizing agents, for example, an amine disulfide, polymeric polysulfide or sulfur olefin adducts. Preferably, the sulfur vulcanizing agent is elemental sulfur. As known to those skilled in the art, sulfur vulcanizing agents are used in an amount ranging from about 0.5 to 8 phr with a range of from 1.5 to 2.25 being preferred.
Accelerators are used to control the time and/or temperature required for vulcanization and to improve the properties of the vulcanizate. In one embodiment, a single accelerator system may be used, i.e., primary accelerator. Conventionally, a primary accelerator is used in amounts ranging from about .5 to 2.0 phr. In another embodiment, combinations of two or more accelerators may be used which may consist of a primary accelerator which is generally used in the larger amount (.5 to 1.0 phr), and a secondary accelerator r~~S, 13~ 4'.~7 which is generally used in smaller amounts (.05-.50 phr) in order to activate and to improve the properties of the w lcanizate. Combinations of these accelerators have been known to produce a synergistic effect of the final properties and are somewhat better than those produced by use of either accelerator alone. In addition, delayed action accelerators may be used which are not effected by normal processing temperatures but produce satisfactory cures at ordinary vulcanization temperatures. Suitable types of accelerators that may be used in the present invention are amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates and xanthates.
Preferably, the primary accelerator is a sulfenamide.
If a secondary accelerator is used, the secondary accelerator is preferably a guanidine, dithiocarbamate or thiuram compound.
The following examples are presented in order to illustrate but not limit the present invention.
Examples 1-11 These experiments contrast the effectiveness of methyl trialkyl(C8-C10) ammonium chloride (MTAAC) at varying levels versus using an equivalent amount of tetraethyl ammonium bromide (TEABr) as a control. The MTAAC and TEABr were used in a typical sidewall rubber stock comprising 40 parts by weight of polyisoprene, 60 parts cis-1,4-polybutadiene, .5 phr of a primary accelerator and conventional amounts of carbon black, tackifier, processing aids, antidegradant, stearic acid, zinc oxide and sulfur. The various additives were compounded using conventional techniques. Cure testing was performed at 150~C on a Monsanto Cure Rheometer according to ASTM test method D-2084-87. The '~
- 13404~7 scorch of the compound was measured according to ASTM
test method D1646-87. Table I shows the results for Examples 1-11.
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o E~
~ ~ ~o oo o C~ ~ ~ oo o o ~ooooo~oooo~
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134~497 The data of Table I show that the control compound (tetraethyl ammonium bromide) showed little or no effect on cure time as evaluated by t25 and t90. Use of methyl trialkyl(C8-C10) ammonium chloride (MTAAC), however, resulted in significantly reduced cure times.
Examples 12-19 Experiments (Examples 12-19) were conducted to demonstrate the enhanced cure rates by the addition of a methyl trialkyl(C8-C10) ammonium salt to a sulfur w lcanizable rubber. An experiment (Example 12, Control) was conducted for comparative purposes.
Experiments (Examples 13 and 14) were conducted to demonstrate the effectiveness of using 68% by weight of methyl trialkyl(C8-C10) ammonium chloride deposited on calcium silicate. Experiments (Examples 15 and 16) were conducted to demonstrate the effectiveness of using 72% by weight of methyl trialkyl(C8-C10) ammonium chloride deposited on silica. Experiments (Examples 17-19) were conducted to demonstrate the effectiveness of using methyl trialkyl(C8-C10) ammonium methyl sulfate. The eight rubber compounds were prepared using varied levels of methyl trialkyl ammonium salt (phr) and a typical sidewall rubber stock comprising 40 parts polyisoprene, 60 parts cis-1,4-polybutadiene, .5 phr of a primary accelerator and conventional amounts of carbon black, tackifier, process oil, antidegradant, stearic acid, zinc oxide, and sulfur. The various additives were compounded using conventional techniques and the samples were evaluated using the curing procedures of Examples 1-11. Table II below lists the cure properties for the compounds of Examples 12-19 which resulted in similar states of cure with different cure rates as seen by t25 and t90.
j,... .
Table II
Example No. 12 13 14 15 16 17 18 19 Amount of methyl trialkyl ~mmnnil~ salt (phr) 0 0.251 .501 o.252 o~502 0.173 0.343 0.503 Rheometer, 150~C
t2, min. 7.0 5.8 5.2 5.8 4.8 5.9 5.2 4.9 t25, min. 9.4 7.5 6.6 7.5 6.3 7.6 6.8 6.3 t90, min. 26.8 19.8 17.4 19.3 16.6 19.6 18.1 17.2 Delta torque, dNm 21.2 24.5 25.9 24.6 26.1 24.2 25.5 25.8 Mocney scorch, 121~C
t5, min. 33.5 28.4 24.6 27.7 24.3 28.5 25.7 23.6 1 68% by weight of methyl trialkyl(C8-C10) ammoni~m chloride deposited on calcium silicate.
Field of the Invention The present invention relates to the vulcanization of a sulfur curable rubber composition.
More particularly, the present invention relates to a method for increasing the rate of cure of a sulfur w lcanizable rubber by the addition of a methyl trialkyl ~mmon;um salt.
Background of the Invention The "rate of cure" is defined as the rate at which crosslinking and the development of the stiffness (modulus) of a rubber compound occurs. As the rubber compound is heated, the properties of the rubber compound change from a soft plastic to a tough elastic material. During the curing step, crosslinks are introduced, which connect the long polymer chains of the rubber. As more crosslinks are introduced, the polymer chains become more firmly connected and the stiffness or modulus of the compound increases. The rate of cure is an important vulcanization parameter since it in part determines the time the compound must be cured, i.e., the "cure time". In the manufacture of vulcanized rubber articles, significant cost savings can be realized through a reduction of cure time. Through enhanced rates of cure, the cure time required to meet m;n;mllm states of cure can be reduced. Given the above, extensive research has been conducted in order to shorten the cure times of rubbers. Therefore, there exists a need for improved methods which enhance 134~497 the rate of cure in the absence of imparting undesirable properties to the vulcanizate.
Summary of the Invention The present invention relates to a method for enhancing the rate of vulcanization of a rubber composition comprising adding to a sulfur vulcanizable rubber a methyl trialkyl ammonium salt of the formula:
R2 (3 wherein R1, R2, and R3 are independently alkyl radicals having 8 to 10 carbon atoms and M is selected from the group consisting of Cl, Br, CH3SO4 and HSO4. In addition, there is disclosed a sulfur w lcanizable rubber composition comprising an elastomer containing olefinic unsaturation, a sulfur vulcanizing agent, an accelerator and a methyl trialkyl am~monium salt selected from the above formula.
Detailed Description of the Invention The present invention relates to the use of a methyl trialkyl ammonium salt as an activator for sulfur curable rubber compositions. A particularly preferred methyl trialkyl am.monium salt is methyl trialkyl(C8-C10) ~mmo~;um chloride which is commercially available under the trademark Adogen~ 464 from Sherex Chemical Company of Dublin, Ohio and from Henkel Corporation, Minneapolis, Minnesota, under the trademark Aliquot~ 336. Methyl trialkyl ammonium salts are generally known as phase-transfer catalysts and are described in U.S. Patent 3,992,432.
134~49 7 For ease in handling, the methyl trialkyl ammonium salt may be deposited on suitable carriers. Examples of carriers which may be used in the present invention include silica, carbon black, alumina, kieselguhr, silica gel and calcium silicate.
Use of a methyl trialkyl ammonium salt does not appear to affect crosslink distribution when used in combination with primary and optionally secondary accelerators. However, along with increased cure rate, there is usually seen an increased curative efficiency in the form of increased state or degree of cure.
The present invention may be used to cure sulfur vulcanizable rubbers or elastomers containing olefinic unsaturation. The phrase "rubber or elastomer containing olefinic unsaturation" is intended to include both natural rubber and its various raw and reclaim forms as well as various synthetic rubbers.
Representative synthetic polymers are the homopolymerization products of butadiene and its homologues and derivatives, for example, methylbutadiene, dimethylbutadiene and pentadiene as well as copolymers such as those formed from butadiene or its homologues or derivatives with other unsaturated monomers. Among the latter are acetylenes, for example, vinyl acetylene; olefins, for example, isobutylene, which copolymerizes with isoprene to form butyl rubber; vinyl compounds, for example, acrylic acid, acrylonitrile (which polymerize with butadiene to form NBR), methacrylic acid and styrene, the latter compound polymerizing with butadiene to form SBR, as well as vinyl esters and various unsaturated aldehydes, ketones and ethers, e.g., acrolein, methyl isopropenyl ketone and vinylethyl ether. Specific examples of synthetic rubbers include neoprene (polychloroprene), '~h polybutadiene (including cis-1,4-polybutadiene), polyisoprene (including cis-1,4-polyisoprene), butyl rubber, copolymers of 1,3-butadiene or isoprene with monomers such as styrene, acrylonitrile and methyl methacrylate, as well as ethylene/propylene terpolymers, also known as ethylene/propylene/diene monomer (EPDM), and in particular, ethylene/propylene/
dicyclopentadiene terpolymers.
The activator used in the present invention may be added to the rubber by any conventional technique such as on a mill or in a Banbury. The amount of methyl trialkyl ammonium salt may vary widely depending on the type of rubber and other compounds present in the vulcanizable composition. Generally, the amount of methyl trialkyl ammonium salt is used in a range of from about .05 to about 5.0 phr with a range of .1 to about 1.5 phr being preferred.
Vulcanization of the rubber is generally carried out at temperatures of between about 100~C and 200~C.
Preferably, the vulcanization is conducted at temperatures ranging from about 110~C to 180~C. Any of the usual vulcanization processes may be used such as heating in a press or mold, heating with superheated steam or hot air or in a salt bath.
In addition to the methyl trialkyl ammonium salt, other rubber additives may also be incorporated in the sulfur vulcanizable material. The additives commonly used in rubber vulcanizates are, for example, carbon black, tackifier resins, processing aids, antioxidants, antiozonants, stearic acid, activators, waxes, oils and peptizing agents. As known to those skilled in the art, depending on the intended use of the sulfur vulcanizable material, certain additives mentioned above are commonly used in conventional amounts.
134~497 Typical additions of carbon black comprise about 20 to 100 parts by weight of diene rubber (phr), preferably 50 to 70 phr. Typical amounts of tackifier resins comprise about 5 to 10 phr. Typical amounts of processing aids comprise about 1 to 5 phr. Typical amounts of antioxidants comprise 1 to about 10 phr.
Typical amounts of antiozonants comprise 1 to about 10 phr. Typical amounts of stearic acid comprise 1 to about 2 phr. Typical amounts of zinc oxide comprise 2 to 5 phr. Typical amounts of waxes comprise 1 to 5 phr. Typical amounts of oils comprise 5 to 30 phr.
Typical amounts of peptizers comprise .l to 1 phr. The presence and relative amounts of the above additives are not an aspect of the present invention.
The vulcanization is conducted in the presence of a sulfur vulcanizing agent. Examples of suitable sulfur vulcanizing agents include elemental sulfur (free sulfur) or sulfur donating vulcanizing agents, for example, an amine disulfide, polymeric polysulfide or sulfur olefin adducts. Preferably, the sulfur vulcanizing agent is elemental sulfur. As known to those skilled in the art, sulfur vulcanizing agents are used in an amount ranging from about 0.5 to 8 phr with a range of from 1.5 to 2.25 being preferred.
Accelerators are used to control the time and/or temperature required for vulcanization and to improve the properties of the vulcanizate. In one embodiment, a single accelerator system may be used, i.e., primary accelerator. Conventionally, a primary accelerator is used in amounts ranging from about .5 to 2.0 phr. In another embodiment, combinations of two or more accelerators may be used which may consist of a primary accelerator which is generally used in the larger amount (.5 to 1.0 phr), and a secondary accelerator r~~S, 13~ 4'.~7 which is generally used in smaller amounts (.05-.50 phr) in order to activate and to improve the properties of the w lcanizate. Combinations of these accelerators have been known to produce a synergistic effect of the final properties and are somewhat better than those produced by use of either accelerator alone. In addition, delayed action accelerators may be used which are not effected by normal processing temperatures but produce satisfactory cures at ordinary vulcanization temperatures. Suitable types of accelerators that may be used in the present invention are amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates and xanthates.
Preferably, the primary accelerator is a sulfenamide.
If a secondary accelerator is used, the secondary accelerator is preferably a guanidine, dithiocarbamate or thiuram compound.
The following examples are presented in order to illustrate but not limit the present invention.
Examples 1-11 These experiments contrast the effectiveness of methyl trialkyl(C8-C10) ammonium chloride (MTAAC) at varying levels versus using an equivalent amount of tetraethyl ammonium bromide (TEABr) as a control. The MTAAC and TEABr were used in a typical sidewall rubber stock comprising 40 parts by weight of polyisoprene, 60 parts cis-1,4-polybutadiene, .5 phr of a primary accelerator and conventional amounts of carbon black, tackifier, processing aids, antidegradant, stearic acid, zinc oxide and sulfur. The various additives were compounded using conventional techniques. Cure testing was performed at 150~C on a Monsanto Cure Rheometer according to ASTM test method D-2084-87. The '~
- 13404~7 scorch of the compound was measured according to ASTM
test method D1646-87. Table I shows the results for Examples 1-11.
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o E~
~ ~ ~o oo o C~ ~ ~ oo o o ~ooooo~oooo~
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134~497 The data of Table I show that the control compound (tetraethyl ammonium bromide) showed little or no effect on cure time as evaluated by t25 and t90. Use of methyl trialkyl(C8-C10) ammonium chloride (MTAAC), however, resulted in significantly reduced cure times.
Examples 12-19 Experiments (Examples 12-19) were conducted to demonstrate the enhanced cure rates by the addition of a methyl trialkyl(C8-C10) ammonium salt to a sulfur w lcanizable rubber. An experiment (Example 12, Control) was conducted for comparative purposes.
Experiments (Examples 13 and 14) were conducted to demonstrate the effectiveness of using 68% by weight of methyl trialkyl(C8-C10) ammonium chloride deposited on calcium silicate. Experiments (Examples 15 and 16) were conducted to demonstrate the effectiveness of using 72% by weight of methyl trialkyl(C8-C10) ammonium chloride deposited on silica. Experiments (Examples 17-19) were conducted to demonstrate the effectiveness of using methyl trialkyl(C8-C10) ammonium methyl sulfate. The eight rubber compounds were prepared using varied levels of methyl trialkyl ammonium salt (phr) and a typical sidewall rubber stock comprising 40 parts polyisoprene, 60 parts cis-1,4-polybutadiene, .5 phr of a primary accelerator and conventional amounts of carbon black, tackifier, process oil, antidegradant, stearic acid, zinc oxide, and sulfur. The various additives were compounded using conventional techniques and the samples were evaluated using the curing procedures of Examples 1-11. Table II below lists the cure properties for the compounds of Examples 12-19 which resulted in similar states of cure with different cure rates as seen by t25 and t90.
j,... .
Table II
Example No. 12 13 14 15 16 17 18 19 Amount of methyl trialkyl ~mmnnil~ salt (phr) 0 0.251 .501 o.252 o~502 0.173 0.343 0.503 Rheometer, 150~C
t2, min. 7.0 5.8 5.2 5.8 4.8 5.9 5.2 4.9 t25, min. 9.4 7.5 6.6 7.5 6.3 7.6 6.8 6.3 t90, min. 26.8 19.8 17.4 19.3 16.6 19.6 18.1 17.2 Delta torque, dNm 21.2 24.5 25.9 24.6 26.1 24.2 25.5 25.8 Mocney scorch, 121~C
t5, min. 33.5 28.4 24.6 27.7 24.3 28.5 25.7 23.6 1 68% by weight of methyl trialkyl(C8-C10) ammoni~m chloride deposited on calcium silicate.
2 72% by weight of methyl trialkyl(C8-C10) ~mmrni1~ chloride deposited on silica.
3 Methyl trialkyl(C8-C10) ~mmnni1~ methyl sulfate.
o 1~404~7 Examples 13-19 demonstrate that methyl trialkyl(C8-C10) ammonium salts are effective in enhancing the rates of cure. The data for Examples 13-16 indicate that use of various carriers are not detrimental to the effectiveness of methyl trialkyl(C8-C10) ammonium chloride. Examples 17-19 suggest that methyl trialkyl(C8-C10) ammonium methyl sulfate is as effective as the other methyl trialkyl ammonium salts used in the present invention.
Examples 20-21 The following experiments were conducted to demonstrate the cure activation of methyl trialkyl ammonium chloride (MTAAC). The formulation for Example 20 (Control) did not contain MTAAC and the formulation for Example 21 contained .30 phr of MTAAC. Both formulations comprised a typical sidewall rubber stock containing 20 parts by weight natural rubber, 20 parts by weight of synthetic polyisoprene, 60 parts by weight polybutadiene, .5 phr of a primary accelerator and conventional amounts of carbon black, waxes, oils, antidegradants, tackifier resin, stearic acid, zinc oxide, and sulfur. The various additives were compounded and the samples were vulcanized by compression molding for 18 minutes at 150~C. The cure properties were evaluated in the same manner as in Examples 1-11. The stress-strain properties were tested according to ASTM method No. D412-87. The data appear in Table III.
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The above data show that addition of a methyl trialkyl ammonium chloride reduces the cure time required to reach optimum cure. The use of the methyl trialkyl ammonium salt has little effect on crosslink distribution and allows for better utilization of sulfur as evidenced by an increase in crosslink densitv (v x 104) and increased 300% modulus.
Examples 22-23 The following experiments were conducted to demonstrate the effectiveness of MTAAC in another sulfur vulcanizable composition. The formulation for Example 22 (Control) did not contain MTAAC and the formulation for Example 23 contained .50 phr of MTAAC.
Both formulations comprised a typical tread rubber stock containing 30 parts by weight of polybutadiene, 70 parts by weight of SBR, 1 phr of a primary accelerator, .15 phr of a secondary accelerator and conventional amounts of carbon black, waxes, oil, peptizer, stearic acid, antidegradant, zinc oxide, and sulfur. The various additives were compounded and the samples were vulcanized by compression molding for 18 minutes at 150~C. After curing, these samples were evaluated using testing procedures of Examples 20-21.
The data are set forth in Table IV.
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Table IV
Physical Properties of Example 22 (Control) and 23 Example 22 (Control)Example 23 Monsanto Rheometer, 1~ Arc, 150~C
Delta torque, MHF ~ ML (dNm) 22.8 24.5 Cure time, t90, min. 20 12.6 Cure time, t25, min. 8.6 6.6 tl pt. rise, min. 6.6 5.4 t90 - tl pt, min. 13.4 7.2 Crosslink Type Analysis % Sx, Polysulfide 63 66 % S2, Disulfide 22 24 % Sl, Monosulfide 15 10 13~0497 Examples 22 and 23 demonstrate the effectiveness of MTAAC in a polybutadiene/SBR blend.
Examples 24 and 25 The following examples were conducted in order to demonstrate the effectiveness of MTAAC in another sulfur vulcanizable composition. The formulation for Example 24 (Control) did not contain MTAAC and the formulation for Example 25 contained 0.2 phr of MT M C.
Both formulations comprised a typical tread rubber stock containing 70 parts by weight of medium vinyl polybutadiene, 30 parts by weight of cis-1,4-polybutadiene, l.l phr of a primary accelerator, .16 phr of a secondary accelerator and conventional amounts of carbon black, waxes, oil, antidegradants, stearic acid, zinc oxide and sulfur.
The various additives were compounded using conventional techniques.
These samples were evaluated by the cure testing procedures used in Examples 20 and 21. The data are set forth in Table V.
~ L340497 Table V
Cure Properties of Example 24 (Control) and 25 Example 24 (Control) Example 25 Monsanto Rheometer, 1~ Arc, 150~C
Delta torque, MHF ML (dNm) 30.7 31.5 Cure time, t90, min. 13.8 11.2 Cure time, t25, min. 7.4 5.8 tl pt rise, min. 5.6 4.6 t90 - tl pt, min. 8.2 6.6 Examples 26-29 These experiments contrast the effectiveness of methyl trialkyl(C8-C10) ammonium chloride (MTAAC) in the presence or absence of an accelerator. The remaining component of the formulations for Examples 26-29 comprised a rubber stock containing 50 parts by weight of SBR, 50 parts by weight of polyisoprene and conventional amounts of oil (28.75 phr), carbon black (50 phr), zinc oxide (3 phr), sulfur (2 phr) and stearic acid (2 phr). In Example 26, no accelerator or MTAAC was used. In Example 27 no accelerator was used but .50 phr MTAAC (68~ by weight of Adogen 464 on calcium silicate carrier) was used. In Example 28, 1.5 phr of accelerator was used but no MTAAC was used. In Example 29 1.5 phr of accelerator was used and .50 phr of MTAAC (same as Example 27) was used. The various additives were compounded using conventional techniques. Cure testing was performed at 150~C on a Monsanto Cure Rheometer according to ASTM test method No. D-2084. The cure properties are given in Table VI
below.
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Table VI
Example 26 Example 27 Example 28 Example 29 Rheometer, 150~C
t2, min. - - 13.20 8.90 t25, min. - - 16.50 11.20 t90, min. - - 24.70 16.60 Delta torque, dNm 4.10 1 8.50 29.10 29.40 1 taken at 60 minutes. ~
:3 134~ i~7 Example 26 shows the very poor cure which occurs when no MTAAC or accelerator is used. The data from Example 27 show that, in the absence of an accelerator, use of MTAAC does not result in any substantial cure.
The data for Example 28 show a typical accelerator effect. The data for Example 29 show a dramatic reduction in cure time when both an accelerator and MTAAC activator are used.
o 1~404~7 Examples 13-19 demonstrate that methyl trialkyl(C8-C10) ammonium salts are effective in enhancing the rates of cure. The data for Examples 13-16 indicate that use of various carriers are not detrimental to the effectiveness of methyl trialkyl(C8-C10) ammonium chloride. Examples 17-19 suggest that methyl trialkyl(C8-C10) ammonium methyl sulfate is as effective as the other methyl trialkyl ammonium salts used in the present invention.
Examples 20-21 The following experiments were conducted to demonstrate the cure activation of methyl trialkyl ammonium chloride (MTAAC). The formulation for Example 20 (Control) did not contain MTAAC and the formulation for Example 21 contained .30 phr of MTAAC. Both formulations comprised a typical sidewall rubber stock containing 20 parts by weight natural rubber, 20 parts by weight of synthetic polyisoprene, 60 parts by weight polybutadiene, .5 phr of a primary accelerator and conventional amounts of carbon black, waxes, oils, antidegradants, tackifier resin, stearic acid, zinc oxide, and sulfur. The various additives were compounded and the samples were vulcanized by compression molding for 18 minutes at 150~C. The cure properties were evaluated in the same manner as in Examples 1-11. The stress-strain properties were tested according to ASTM method No. D412-87. The data appear in Table III.
~ ~.
. .
13~U497 ,.
C~ U~ o U~
u~ o ~ ~ r~ ~
a~ . . . . . . ~ ~ O
o U~ ~
X o E~
C~
aJ
~a o ,~
o O
o u~ u~ O u~
o C~ ~ ~ ~ o ~ ~
o U~ o o C~
.
X ~ 5 a~ X
.n ~
~ ~ Cq E~ o ~ c"
¢ ~,1 .~ o ~ _ ~ U~
o ~ ~ ~,~cn U~ ~ ~ O
O - -- ~ ,~
a) o Z~ ~ O
¢
q~ o - O ~ y U~
~ o ~ ~ ~ ~ ~ o b~
o a~ - C ~ ~
G - - u~ O ~ O ~~ E3 a~ 1 Y Y ~1 u~ o O O~ O ~~ O C/7 ~ ~1 Z
~~ ~ oo o cn ~ u~ O
C ~ h ~ C~ ~1 1340 1.97 .
The above data show that addition of a methyl trialkyl ammonium chloride reduces the cure time required to reach optimum cure. The use of the methyl trialkyl ammonium salt has little effect on crosslink distribution and allows for better utilization of sulfur as evidenced by an increase in crosslink densitv (v x 104) and increased 300% modulus.
Examples 22-23 The following experiments were conducted to demonstrate the effectiveness of MTAAC in another sulfur vulcanizable composition. The formulation for Example 22 (Control) did not contain MTAAC and the formulation for Example 23 contained .50 phr of MTAAC.
Both formulations comprised a typical tread rubber stock containing 30 parts by weight of polybutadiene, 70 parts by weight of SBR, 1 phr of a primary accelerator, .15 phr of a secondary accelerator and conventional amounts of carbon black, waxes, oil, peptizer, stearic acid, antidegradant, zinc oxide, and sulfur. The various additives were compounded and the samples were vulcanized by compression molding for 18 minutes at 150~C. After curing, these samples were evaluated using testing procedures of Examples 20-21.
The data are set forth in Table IV.
., ~, . ~
",,L ~
.~
. _ ~, . . .
Table IV
Physical Properties of Example 22 (Control) and 23 Example 22 (Control)Example 23 Monsanto Rheometer, 1~ Arc, 150~C
Delta torque, MHF ~ ML (dNm) 22.8 24.5 Cure time, t90, min. 20 12.6 Cure time, t25, min. 8.6 6.6 tl pt. rise, min. 6.6 5.4 t90 - tl pt, min. 13.4 7.2 Crosslink Type Analysis % Sx, Polysulfide 63 66 % S2, Disulfide 22 24 % Sl, Monosulfide 15 10 13~0497 Examples 22 and 23 demonstrate the effectiveness of MTAAC in a polybutadiene/SBR blend.
Examples 24 and 25 The following examples were conducted in order to demonstrate the effectiveness of MTAAC in another sulfur vulcanizable composition. The formulation for Example 24 (Control) did not contain MTAAC and the formulation for Example 25 contained 0.2 phr of MT M C.
Both formulations comprised a typical tread rubber stock containing 70 parts by weight of medium vinyl polybutadiene, 30 parts by weight of cis-1,4-polybutadiene, l.l phr of a primary accelerator, .16 phr of a secondary accelerator and conventional amounts of carbon black, waxes, oil, antidegradants, stearic acid, zinc oxide and sulfur.
The various additives were compounded using conventional techniques.
These samples were evaluated by the cure testing procedures used in Examples 20 and 21. The data are set forth in Table V.
~ L340497 Table V
Cure Properties of Example 24 (Control) and 25 Example 24 (Control) Example 25 Monsanto Rheometer, 1~ Arc, 150~C
Delta torque, MHF ML (dNm) 30.7 31.5 Cure time, t90, min. 13.8 11.2 Cure time, t25, min. 7.4 5.8 tl pt rise, min. 5.6 4.6 t90 - tl pt, min. 8.2 6.6 Examples 26-29 These experiments contrast the effectiveness of methyl trialkyl(C8-C10) ammonium chloride (MTAAC) in the presence or absence of an accelerator. The remaining component of the formulations for Examples 26-29 comprised a rubber stock containing 50 parts by weight of SBR, 50 parts by weight of polyisoprene and conventional amounts of oil (28.75 phr), carbon black (50 phr), zinc oxide (3 phr), sulfur (2 phr) and stearic acid (2 phr). In Example 26, no accelerator or MTAAC was used. In Example 27 no accelerator was used but .50 phr MTAAC (68~ by weight of Adogen 464 on calcium silicate carrier) was used. In Example 28, 1.5 phr of accelerator was used but no MTAAC was used. In Example 29 1.5 phr of accelerator was used and .50 phr of MTAAC (same as Example 27) was used. The various additives were compounded using conventional techniques. Cure testing was performed at 150~C on a Monsanto Cure Rheometer according to ASTM test method No. D-2084. The cure properties are given in Table VI
below.
~.~
Table VI
Example 26 Example 27 Example 28 Example 29 Rheometer, 150~C
t2, min. - - 13.20 8.90 t25, min. - - 16.50 11.20 t90, min. - - 24.70 16.60 Delta torque, dNm 4.10 1 8.50 29.10 29.40 1 taken at 60 minutes. ~
:3 134~ i~7 Example 26 shows the very poor cure which occurs when no MTAAC or accelerator is used. The data from Example 27 show that, in the absence of an accelerator, use of MTAAC does not result in any substantial cure.
The data for Example 28 show a typical accelerator effect. The data for Example 29 show a dramatic reduction in cure time when both an accelerator and MTAAC activator are used.
Claims (11)
1. A method for increasing the rate of vulcanization of a rubber composition comprising adding to a sulfur vulcanizable rubber from about 0.05 to about 5.0 phr of a methyl trialkyl ammonium salt of the formula:
wherein R1, R2, and R3 are independently alkyl radicals having 8 to 10 carbon atoms and M is selected from the group consisting of Cl, Br, CH3SO4 and HSO4.
wherein R1, R2, and R3 are independently alkyl radicals having 8 to 10 carbon atoms and M is selected from the group consisting of Cl, Br, CH3SO4 and HSO4.
2. The method of claim 1 wherein M is Cl or CH3SO4.
3. The method of claim 2 wherein M is Cl.
4. The method of claim 2 wherein M is CH3SO4.
5. The method of claim 1 wherein said sulfur vulcanizable rubber contains an elastomer containing olefinic unsaturation and is selected from the group consisting of natural rubber, neoprene, polyisoprene, butyl rubber, polybutadiene, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, isoprene-styrene copolymer, methyl methacrylate-isoprene copolymer, acrylonitrile-isoprene copolymer, acrylonitrile-butadiene copolymer, EPDM or mixtures thereof.
6. The method of claim 5 wherein said sulfur vulcanizable rubber is selected from the group consisting of natural rubber, SBR, polyisoprene, or mixtures thereof.
7. A sulfur vulcanizable rubber composition comprising an elastomer containing olefinic unsaturation, a vulcanizing agent, an accelerator and from about 0.05 to about 5.0 phr of a methyl trialkyl ammonium salt of the formula:
wherein R1, R2, and R3 are independently alkyl radicals having
wherein R1, R2, and R3 are independently alkyl radicals having
8 to 10 carbon atoms and M is selected from the group consisting of Cl, Br, CH3SO4 and HSO4.
8. The sulfur vulcanizable rubber composition of claim 7 wherein M is Cl or CH3SO4.
8. The sulfur vulcanizable rubber composition of claim 7 wherein M is Cl or CH3SO4.
9. The sulfur curable rubber composition of claim 7 wherein said elastomer is selected from the group consisting of natural rubber, neoprene, polyisoprene, butyl rubber, polybutadiene, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, isoprene-styrene copolymer, methyl methacrylate-isoprene copolymer, acrylonitrile-isoprene copolymer, acrylonitrile-butadiene copolymer, EPDM or mixtures thereof.
10. The sulfur curable rubber composition of claim 7 wherein the sulfur vulcanizing agent is selected from the group consisting of elemental sulfur, amine disulfide, polymeric polysulfide or sulfur olefin adducts.
11. The sulfur vulcanizable composition of claim 7 wherein the accelerator is selected from the group consisting of amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates, xanthates or mixtures thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US29079688A | 1988-12-28 | 1988-12-28 | |
| US290,796 | 1988-12-28 |
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| Publication Number | Publication Date |
|---|---|
| CA1340497C true CA1340497C (en) | 1999-04-13 |
Family
ID=23117606
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000609570A Expired - Fee Related CA1340497C (en) | 1988-12-28 | 1989-08-28 | Vulcanizate activator system for rubber compositions |
Country Status (14)
| Country | Link |
|---|---|
| KR (1) | KR900009701A (en) |
| CN (2) | CN1062574C (en) |
| AR (1) | AR247219A1 (en) |
| AT (1) | ATE105001T1 (en) |
| BR (1) | BR8906667A (en) |
| CA (1) | CA1340497C (en) |
| DK (1) | DK668089A (en) |
| FI (1) | FI99134C (en) |
| IE (1) | IE66562B1 (en) |
| MA (1) | MA21696A1 (en) |
| MY (1) | MY105906A (en) |
| NO (1) | NO179951C (en) |
| PT (1) | PT92754B (en) |
| ZA (1) | ZA899579B (en) |
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| ITTO20110525A1 (en) * | 2011-06-15 | 2012-12-16 | Bridgestone Corp | METHOD OF VULCANIZATION WITH MICROWAVE OF RUBBER COMPOUNDS |
| KR101411114B1 (en) * | 2012-08-29 | 2014-06-25 | 유태우 | Pad and it's making method for acupuncture of a imagenation cure |
| CN104961982A (en) * | 2015-07-28 | 2015-10-07 | 太仓市晨洲塑业有限公司 | Modified butyl rubber |
| CN114854057A (en) * | 2022-04-26 | 2022-08-05 | 濮阳林氏医疗制品有限公司 | Low-temperature vulcanization package group and preparation method and application thereof |
-
1989
- 1989-08-28 CA CA000609570A patent/CA1340497C/en not_active Expired - Fee Related
- 1989-12-14 MA MA21956A patent/MA21696A1/en unknown
- 1989-12-14 ZA ZA899579A patent/ZA899579B/en unknown
- 1989-12-18 FI FI896047A patent/FI99134C/en not_active IP Right Cessation
- 1989-12-21 AR AR89315780A patent/AR247219A1/en active
- 1989-12-21 BR BR898906667A patent/BR8906667A/en not_active IP Right Cessation
- 1989-12-22 AT AT8989630234T patent/ATE105001T1/en not_active IP Right Cessation
- 1989-12-22 NO NO895244A patent/NO179951C/en not_active IP Right Cessation
- 1989-12-27 KR KR1019890019688A patent/KR900009701A/en not_active Application Discontinuation
- 1989-12-27 MY MYPI89001864A patent/MY105906A/en unknown
- 1989-12-27 DK DK668089A patent/DK668089A/en not_active Application Discontinuation
- 1989-12-28 CN CN89106900A patent/CN1062574C/en not_active Expired - Fee Related
- 1989-12-28 PT PT92754A patent/PT92754B/en not_active IP Right Cessation
- 1989-12-28 IE IE419189A patent/IE66562B1/en not_active IP Right Cessation
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- 1998-09-28 CN CN98120866A patent/CN1277210A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| ZA899579B (en) | 1990-09-26 |
| FI896047A0 (en) | 1989-12-18 |
| NO895244L (en) | 1990-06-29 |
| FI99134C (en) | 1997-10-10 |
| PT92754A (en) | 1990-06-29 |
| IE894191L (en) | 1990-06-28 |
| NO895244D0 (en) | 1989-12-22 |
| MA21696A1 (en) | 1990-07-01 |
| CN1043726A (en) | 1990-07-11 |
| MY105906A (en) | 1995-02-28 |
| DK668089A (en) | 1990-06-29 |
| BR8906667A (en) | 1990-09-11 |
| KR900009701A (en) | 1990-07-05 |
| FI99134B (en) | 1997-06-30 |
| DK668089D0 (en) | 1989-12-27 |
| NO179951B (en) | 1996-10-07 |
| PT92754B (en) | 1995-11-30 |
| AR247219A1 (en) | 1994-11-30 |
| CN1062574C (en) | 2001-02-28 |
| IE66562B1 (en) | 1996-01-24 |
| NO179951C (en) | 1997-01-15 |
| CN1277210A (en) | 2000-12-20 |
| ATE105001T1 (en) | 1994-05-15 |
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