CA1217598A - Method for modifying rubbers - Google Patents
Method for modifying rubbersInfo
- Publication number
- CA1217598A CA1217598A CA000430823A CA430823A CA1217598A CA 1217598 A CA1217598 A CA 1217598A CA 000430823 A CA000430823 A CA 000430823A CA 430823 A CA430823 A CA 430823A CA 1217598 A CA1217598 A CA 1217598A
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- Prior art keywords
- rubber
- general formula
- ester group
- lewis acid
- group
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- 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
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- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
A B S T R A C T
A method for modifying a rubber having a un-saturated carbon bond which comprises reacting the rubber with an organic compound represented by the general formula wherein -R represents a hydrocarbon group, and -X is -H, -CN or -?-Y in which -Y
represents an organic atomic grouping, in the presence of a Lewis acid to introduce an ester group. Optionally, the ester group introduced is converted into a carboxyl group by chemically treating the reaction product.
A method for modifying a rubber having a un-saturated carbon bond which comprises reacting the rubber with an organic compound represented by the general formula wherein -R represents a hydrocarbon group, and -X is -H, -CN or -?-Y in which -Y
represents an organic atomic grouping, in the presence of a Lewis acid to introduce an ester group. Optionally, the ester group introduced is converted into a carboxyl group by chemically treating the reaction product.
Description
I
This invention relates to a method for modifying rubbers having an unsaturated carbon bond.
Methods have previously been known to introduce polar group such as a carboxyl group into rubbers, for example to add malefic android or glyoxal to rubber, in order to improve the properties of rubbers in the unvulcanized and vulcanized states, such as green strength and adhesion. Many of these methods, how-ever, have the defect that since side-reactions such as gellation of rubbers or the decrease of their molecular weight are liable to take place during the addition-reaction, the strength properties of the vulcanized products are reduced, or the rate of the reaction is slow.
It is an object of this invention to provide a method for modifying rubbers which is free from this defect.
The object of this invention is achieved by a method which comprises reacting a rubber having an unsaturated carbon bond with an organic compound represented by the general formula o C-O-R
O C X
wherein -R represents a hydrocarbon group, and -X
represents -H, -ON or -C-Y in which Y represents -R1, o -OR or -NR3R4 in which -R1, -R2, -R3 and -R4 are hydra-carbon group sin the presence of a Lewis acid to introduce an ester group.
Examples of the rubber having an unsaturated carbon bond include homopolymers of conjugated dines such as butadiene, is-prone, piperylenet 2,3-dimethylbutadiene and chloroprene; Capella-mews of two or more of such conjugated dines; copolymers of such conjugated dines with other monomers; ring-opened polymers of " or Jo I "I
so Jo cycloolefins such as cyclopentene and norbornene;
polymers of dines such as ethylidenenorbornene and cyclopentadiene; and copolymers of the aforesaid dines with olefins. Specific examples are natural rubber, Gaul gum, polyisoprene rubber, polybutadiene rubber, styrenes butadiene copolymer rubber, butadiene-isoprene copolymer rubber, isoprene-styrene copolymer rubber, butadiene-isoprene-styrene copolymer rubber, butadiene-piperylene copolymer rubber, butadiene-propylene alternate copolymer rubber, polypentenamer, ethylene-propylene-diene copolymer rubbers, bottle rubber, butadiene-acrylonitrile copolymer rubber, butadiene-isoprene-acrylonitrile copolymer rubber, polychloroprene rubber, styrene-butadiene-styrene block copolymer rubber, and styrene-isoprene-styrene block copolymer rubber.
Typical examples of the organic compound represented by the general formula o OX
are those of the above formula in which -R represents an aliphatic, alicyclic or aromatic group, provided that when -X is -C-Y, -Y represents -Al, -OR or -NR3R4 in which -Al, -R2, -R3 and -R4 are hydrocarbon groups particularly aliphatic, alicyclic or aromatic hydrocarbon groups.
More specifically, examples of the organic compound of the above formula in which -X is -H are esters of ~lyoxylic acid such as methyl glyoxylate, ethyl glyoxylate, isopropyl glyoxylate, tertiary bottle glyoxylate, bouncily glyoxylate, phenol glyoxylate, octal glyoxylate and stroll glyoxylate. Examples of the organic compound of the above formula in which -X is -ON
are esters of oxocyanoacetic acid such as methyl ox-cyanoacetate, ethyl oxocyanoacetate and tertiary bottle lo to oxocyanoacetate. Examples of the organic compound of the above formula in which -X is -C-Y are esters of oxoacyl-acetic acids of the formula o CRY
CRY
O
such as methyl oxoacetoacetate, bottle oxoacetoacetate, methyl oxobenzoylacetate and bottle oxobenzoylacetate;
esters of oxomalonic acid of the formula lot CRY
CRY
o such as dim ethyl oxomalonate, deathly oxomalonate, diisopropyl oxomalonate, di-tertiary bottle oxomalonate and dibenzyl oxomalonate; and esters of Dixie-(dialkylamino)propionic acids of the formula o CRY
" R
such as ethyl 2,3-dioxo-3-(dimethylamino)propionate and methyl 2~3-dioxo-3-(diethylamino)propionate.
The amount of the organic compound used is not particularly limited. Usually, its amount is 0.0001 to 20 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of the unsaturated rubber.
The Lewis acid used in this invention may be those which are generally known. Typical examples are halides, salts, etc. of metals or semi-metals, organic halides and complexes, for example halides of elements such as Be, B, Al, Bit P, S, Tip V, Fe, Zen, Gay Go, As, So, Or, Nub 9 Mow Cud, Sun, Sub, To, Tax W, Hug, By and U, or oxygen-element combinations such as PO, So, SO, S02 and VOW Specific examples include BF3, BF30(C2H5)2, (CH3)2BF, BC13, Alec, AlBr3, (Cowlick, PUKE, Tokyo, VCl~, Mohawk, Snuck, (CH3)SnC13, SbC15, Tokyo, Tuber, Fake, WACO and (CF3C00)2Hg. Among them, Snuck, BF30(C2H5)2, Fake and Tokyo are preferred because they lead to a high rate of reaction and reduced side-reactions such as gellation of rubber.
The amount of the Lewis acid used is not par-titularly limited. usually, its amount is 0 01 to 5 moles, preferably 0.05 to 2 moles, per mole of the organic compound.
The reaction in accordance with this invention is carried out usually in a suitable solvent, or in the absence of a solvent in a kneader. Industrially, the reaction is advantageously carried out in the rubber cement after the polymerization. Examples of the solvent that may be used include aromatic solvents such as Bunsen and Tulane, paraffinic solvents such as butane and hexane, and halogenated hydrocarbon solvents such as chloroform and dichloroethane. Suitable solvents are those which are inert to the reaction and dissolve the rubber.
The organic solvent may be added to the react lion system all at a time in the early stage of the reaction. Or it may be added portions or continuously during the reaction. The Lewis acid and the organic compound may be added simultaneously or separately. Or a mixture of these may be added. During the reaction, it is necessary to maintain the reaction system in an an hydrous condition or the water content of the reaction system should be maintained at a restricted value. The reaction temperature is not particularly limited. Usual-lye it is -20 C to 100 C, preferably -10 C to 60 C.
The reaction time is neither restricted in particular, and may range from 10 seconds to 10 hours as the case '3'.
may be.
In the present invention, the unsaturated rubber reacted as above may be hydrolyzed with acids, alkalies, etc. or reacted with a radical generator such as curium ammonium nitrate or sodium peridot to convert a part or the whole of the ester group introduced into the unsaturated rubber to a carboxyl group. When an ox-malonate group is introduced into the unsaturated rubber, the reaction with the radical generator is preferred to the hydrolysis. This secondary reaction may also be carried out in solution or in a kneader.
When the reaction in this invention is carried out in a solvent, the reaction can be stopped, and the rubber can be coagulated 9 by pouring the reaction soul-lion into a large amount Or an alcohol or hot water with stirring. as required, the coagulated rubber is then washed to rove organic materials. Subsequent drying gives a modified rubber.
An unvulcanized compound obtained by mixing the resulting modified rubber with conventional rubber chemicals such as a reinforcing agent, a filler, a vulcanizer, a vulcanization accelerator, a vulcanization aid, a softening agent, a tackifier or an antioxidant exhibit excellent green strength. Vulcanized products of the compound have excellent strength properties such as tear strength. An unvulcanized compound of the modified rubber in which the ester group has been partly or wholly converted to a carboxyl group by the method described above is characterized by having higher green strength.
The kind Or the reinforcing agent to be blended with the modified rubber is not particularly limited.
Examples of preferred reinforcing agents include carbon blacks having an average particle diameter of 10 my to 500 my, for example channel blacks abbreviated as EPIC, MPC, HPC, CC, etc., furnace blacks abbreviated as SAFE
ISAF, HA, MA, FEZ, HMF, SURF, SPY, GPF, APP,-FF, OF, etc., thermal blacks abbreviated as FIT, MT, etc., and I
acetylene black; and silica-type reinforcing agents having an average particle diameter of 10 my to 100 my such as silicic android obtained by the dry method, hydrous silicic acid obtained by the wet method, and synthetic silicate salts.
Calcium carbonate, clay and talc may be used as the filler.
The amount of the reinforcing agent and/or the filler to be blended is usually 1 to 200 parts by weight, preferably 10 to 120 parts by weight, per 1~0 parts by weight of the modified rubber, selected depend-in upon the end use of the final product.
Sulfur and sulfur donors Or the thrum and thiazole series are typical vulcanizers. As required, peroxides, polyamides, metal oxides, urethane vulcanizers and resin vulcanizers may be used. Examples of the vulcanization accelerator may be those of the sulfonamide, thrum, thiazole, guanidine, mercaptotriazine, and aldehyde-amine series. Examples of the vulcanization aid are carboxylic acids such as Starkey acid and oleic acid, and metal compounds such as zinc Stewart, zinc oxide, magnesium oxide, calcium hydroxide and lead carbonate. Paraffinic, naphthenic and aromatic process oils may be used as the softening agent. Examples of the tackifier are rosin, petroleum hydrocarbon resins, Cameron resins and phenol-terpenene resins. Amine and phenols may be used as the antioxidant. The above-exemplified vulcanization accelerators and aids are used mainly for vulcanization with sulfur or sulfur donors.
The modified rubber obtained by the method ox this invention may be blended in any desired proportion with other rubbers such as natural rubber, styrenes butadiene copolymer rubber, polybutadiene rubber, and unmodified polyisoprene rubber.
The method of mixing the individual ingredients is not particularly limited, and usually, various types of rubber kneading machines are used. The carbon black sly and the process oil may be mixed with rubber in the step of producing the starting rubber or in the step of modifying the rubber to form a carbon master batch and an oil master batch.
Since a compound of the modified rubber obtained by the method of this invention has excellent green strength in the unvulcanized state and excellent dynamic properties such as tear strength, fatigue resistance and rebound after vulcanization, it is useful as the carcasses, treads, side walls, bead fillers and inner liners of vehicle tires, particularly large-sized tires for tracks and buses, various anti vibratory rubbers, industrial belts and hoses.
The modified rubber obtained by the method of this invention may also be formed into a latex and used in ordinary applications of lattices.
The following examples illustrate the present invention specifically.
Analysis of the modified rubber, preparation of the unvulcanized compound and the vulcanized product of the modified rubber, and testing of the properties of these materials in the examples were carried out by the following methods.
Ester group content of the rubber The modified rubber from which the remaining low-molecular-weight components were removed was sub-jetted to infrared absorption spectrometer. The content of the ester group introduced into the rubber was determined from the ratio between the absorption at 30 1720 - 1735 Cal due to the C=0 stretching vibration of the ester and the absorption at 1660 cm 1 due to the C=0 stretching vibration of the rubber.
Carboxyl group content of the rubber After the low-molecular-weight components were removed from the rubber, its carboxyl group content was measured by a neutralization titration method.
Amount of gel About 0.2 g of small pieces of a rubber sample were put in a square cage made of an Messiah wire gauze and measuring 3 cm at each side, and immersed for 24 hours in Tulane. The amount (%) of a gel was determined from the dry weight of the rubber remaining in the cage.
A gel content of 2% or below is considered to represent substantially no gellation.
Preparation of an unvulcanized compound of rubber The modified rubber was kneaded with the various compounding chemicals in the following recipe excepting sulfur and the vulcanization accelerator in a small-sized Banbur mixer. Sulfur and the vulcanize-` 15 lion accelerator were added to the resulting mixture one small roll and kneaded to prepare an unvulcanized rubber compound.
Compounding recipe:-Rubber (parts by weight) HA carbon 50 Aromatic process oil 5 Zinc oxide 5 Starkey acid 2 Sulfur 2.5 N-oxydiethylene-2-benzothiazyl sulfonamide (vulcanization accelerator) 0.8 N-isopropyl-N'-phenyl-p-phenylenediamine1.0 Wallace plasticity The plasticity of rubber or an unvulcanized rubber compound was measured at 100 C. by a Wallace's rapid plastometer.
Green strength The unvulcanized rubber compound was press-formed at 100 C for 5 minutes to form an unvulcanized rubber sheet having a thickness of' 2 mm. A dumbbell-shaped JIG No. 3 test specimen was punched out from Truly leak issue g the sheet. The test specimen was subjected to a tensile test at 25 C. at a tensile speed of 500 mm/min., and its tensile stress at 500% stretch was determined and defined as the green strength.
Vulcanization speed This is represented by the time (T95) which elapsed until the torque measured at 145 C by an oscillating disc remoter reached 95% of the maximum torque.
Tensile test An unvulcanized rubber compound was press-cured at 145 C for a predetermined period of time to form a 2 mm-thick sheet, and a Dumbell-shaped No. 3 test specimen stipulated in JIS-K6301 was punched out. The test specimen was subjected to a tensile test at a tensile speed of 500 mm/min. at 25 C.
Tear strength Six rectangular test specimens, each 15 mm wide and 100 mm long, were punched out from a 2 mm-thick vulcanized sheet. Three of the test specimens had a longitudinal direction corresponding with the grain direction, and the remaining three had a widths direction corresponding with the grain direction. In each test specimen, a cut, 6 mm long, was formed central-lye in one longitudinal side edge at right angles thereto by a safety razor blade. The tear strengths of the test specimens were measured at a tensile speed of 500 mm/min.
at 25 C, and the average of the six strength values was calculated.
Example 1 One hundred and sixty grams of polyisoprene rubber having a Swiss linkage content of 98% (sample A) was dissolved in 4 liters of dehydrated Nixon, and in a sealed glass vessels (separable flask), ethyl glyoxylate and Snuck were added in the amounts indicated in Table 1 to the solution at 25 C in an atmosphere of nitrogen, and the mixture was reacted for 60 minutes.
One hundred milliliters of methanol was poured into the reaction mixture (whereby it was presumed the addition-reaction was stopped). Thereafter, the reaction mixture was poured into acetone to coagulate the rubber complete-lye The coagulated product was cut to pieces and washed.
The small pieces of the rubber were then immersed in 3 liters of acetone containing about 2 g of 2,6-ditertiary butyl-4-methylphenol (antioxidant) and then dried for one day in a vacuum dryer. Thus, samples B, C, D and E shown in Table 1 were obtained.
It is seen that samples D and E in accordance with this invention were modified (introduction of the ester group) without substantial elysian and molecular weight reduction (change in the Wallace plasticity).
Table 1 Ester group _ EthylSnC14 introduced 11 Amount Sample glyoxyl~te into rubber We ace Of gel go (moles/100 g P Y (o/o) of rubber) _ _ Jo A _ _ _ 46 0.6 B 1.2 O O 48 0.2 C O 3.12 O 49 0.4 o' .
D 1.2 3.12 0.0059 49 0.4 E 2.4 6.25 0.0120 49 I
*This value was obtained with a rubber prepared by performing the same operation as in the preparation of the other samples except that ethyl glyoxylate and Snuck were not added to sample A, and is not the amount of gel originally contained in sample A (the gel which was originally contained in Sample A mostly disappeared when sample A was dissolved in Nixon).
The properties of unvulcanized compounds of the samples indicated in Table 1 and their vulcanization products were measured, and the results are shown in Table 2.
ISLES d _ _ _. _ _ Jo Us 0 JO
I Lo O En So _ .
N I JO O O O O
I? bit Go Lo JO
I Lo In Us us a) Jo 5 ,1 0 ox 0 a) us AL) 0 0 Ox Sue 0 O E- En Jo G~V~E3 _ us o O O I: S. by En .
So I "'~'~ .. _ , a) _ D G Jo V
US 0 t-OX E
Jo _ .
Ox O O
So i I .
O
pa) ED ED
.
a at I
use Dow Tofu US
12 _ It is seen from Table 2 that the samples D and E in accordance with this invention have excellent green strength and tear strength.
Example 2 The same polyisoprene rubber as used in Example 1 (160 g) was dissolved in 3 liters of dehydrated Tulane, and in a sealed glass vessel (separable flask), tertiary bottle glyoxylate and Snuck were added in the amounts indicated in Table 3 to the solution at 25 C in an atmosphere of nitrogen. The mixture was reacted for 30 minutes, and then 50 ml of methanol was poured into the reaction mixture (whereby it was presumed the addition-reaction was stopped). Then, the reaction mixture was poured into 3 liters of methanol to coagulate the rubber completely. The coagulated product was cut to small pieces and washed. The small rubber pieces were then immersed in 3 liters of methanol containing about
This invention relates to a method for modifying rubbers having an unsaturated carbon bond.
Methods have previously been known to introduce polar group such as a carboxyl group into rubbers, for example to add malefic android or glyoxal to rubber, in order to improve the properties of rubbers in the unvulcanized and vulcanized states, such as green strength and adhesion. Many of these methods, how-ever, have the defect that since side-reactions such as gellation of rubbers or the decrease of their molecular weight are liable to take place during the addition-reaction, the strength properties of the vulcanized products are reduced, or the rate of the reaction is slow.
It is an object of this invention to provide a method for modifying rubbers which is free from this defect.
The object of this invention is achieved by a method which comprises reacting a rubber having an unsaturated carbon bond with an organic compound represented by the general formula o C-O-R
O C X
wherein -R represents a hydrocarbon group, and -X
represents -H, -ON or -C-Y in which Y represents -R1, o -OR or -NR3R4 in which -R1, -R2, -R3 and -R4 are hydra-carbon group sin the presence of a Lewis acid to introduce an ester group.
Examples of the rubber having an unsaturated carbon bond include homopolymers of conjugated dines such as butadiene, is-prone, piperylenet 2,3-dimethylbutadiene and chloroprene; Capella-mews of two or more of such conjugated dines; copolymers of such conjugated dines with other monomers; ring-opened polymers of " or Jo I "I
so Jo cycloolefins such as cyclopentene and norbornene;
polymers of dines such as ethylidenenorbornene and cyclopentadiene; and copolymers of the aforesaid dines with olefins. Specific examples are natural rubber, Gaul gum, polyisoprene rubber, polybutadiene rubber, styrenes butadiene copolymer rubber, butadiene-isoprene copolymer rubber, isoprene-styrene copolymer rubber, butadiene-isoprene-styrene copolymer rubber, butadiene-piperylene copolymer rubber, butadiene-propylene alternate copolymer rubber, polypentenamer, ethylene-propylene-diene copolymer rubbers, bottle rubber, butadiene-acrylonitrile copolymer rubber, butadiene-isoprene-acrylonitrile copolymer rubber, polychloroprene rubber, styrene-butadiene-styrene block copolymer rubber, and styrene-isoprene-styrene block copolymer rubber.
Typical examples of the organic compound represented by the general formula o OX
are those of the above formula in which -R represents an aliphatic, alicyclic or aromatic group, provided that when -X is -C-Y, -Y represents -Al, -OR or -NR3R4 in which -Al, -R2, -R3 and -R4 are hydrocarbon groups particularly aliphatic, alicyclic or aromatic hydrocarbon groups.
More specifically, examples of the organic compound of the above formula in which -X is -H are esters of ~lyoxylic acid such as methyl glyoxylate, ethyl glyoxylate, isopropyl glyoxylate, tertiary bottle glyoxylate, bouncily glyoxylate, phenol glyoxylate, octal glyoxylate and stroll glyoxylate. Examples of the organic compound of the above formula in which -X is -ON
are esters of oxocyanoacetic acid such as methyl ox-cyanoacetate, ethyl oxocyanoacetate and tertiary bottle lo to oxocyanoacetate. Examples of the organic compound of the above formula in which -X is -C-Y are esters of oxoacyl-acetic acids of the formula o CRY
CRY
O
such as methyl oxoacetoacetate, bottle oxoacetoacetate, methyl oxobenzoylacetate and bottle oxobenzoylacetate;
esters of oxomalonic acid of the formula lot CRY
CRY
o such as dim ethyl oxomalonate, deathly oxomalonate, diisopropyl oxomalonate, di-tertiary bottle oxomalonate and dibenzyl oxomalonate; and esters of Dixie-(dialkylamino)propionic acids of the formula o CRY
" R
such as ethyl 2,3-dioxo-3-(dimethylamino)propionate and methyl 2~3-dioxo-3-(diethylamino)propionate.
The amount of the organic compound used is not particularly limited. Usually, its amount is 0.0001 to 20 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of the unsaturated rubber.
The Lewis acid used in this invention may be those which are generally known. Typical examples are halides, salts, etc. of metals or semi-metals, organic halides and complexes, for example halides of elements such as Be, B, Al, Bit P, S, Tip V, Fe, Zen, Gay Go, As, So, Or, Nub 9 Mow Cud, Sun, Sub, To, Tax W, Hug, By and U, or oxygen-element combinations such as PO, So, SO, S02 and VOW Specific examples include BF3, BF30(C2H5)2, (CH3)2BF, BC13, Alec, AlBr3, (Cowlick, PUKE, Tokyo, VCl~, Mohawk, Snuck, (CH3)SnC13, SbC15, Tokyo, Tuber, Fake, WACO and (CF3C00)2Hg. Among them, Snuck, BF30(C2H5)2, Fake and Tokyo are preferred because they lead to a high rate of reaction and reduced side-reactions such as gellation of rubber.
The amount of the Lewis acid used is not par-titularly limited. usually, its amount is 0 01 to 5 moles, preferably 0.05 to 2 moles, per mole of the organic compound.
The reaction in accordance with this invention is carried out usually in a suitable solvent, or in the absence of a solvent in a kneader. Industrially, the reaction is advantageously carried out in the rubber cement after the polymerization. Examples of the solvent that may be used include aromatic solvents such as Bunsen and Tulane, paraffinic solvents such as butane and hexane, and halogenated hydrocarbon solvents such as chloroform and dichloroethane. Suitable solvents are those which are inert to the reaction and dissolve the rubber.
The organic solvent may be added to the react lion system all at a time in the early stage of the reaction. Or it may be added portions or continuously during the reaction. The Lewis acid and the organic compound may be added simultaneously or separately. Or a mixture of these may be added. During the reaction, it is necessary to maintain the reaction system in an an hydrous condition or the water content of the reaction system should be maintained at a restricted value. The reaction temperature is not particularly limited. Usual-lye it is -20 C to 100 C, preferably -10 C to 60 C.
The reaction time is neither restricted in particular, and may range from 10 seconds to 10 hours as the case '3'.
may be.
In the present invention, the unsaturated rubber reacted as above may be hydrolyzed with acids, alkalies, etc. or reacted with a radical generator such as curium ammonium nitrate or sodium peridot to convert a part or the whole of the ester group introduced into the unsaturated rubber to a carboxyl group. When an ox-malonate group is introduced into the unsaturated rubber, the reaction with the radical generator is preferred to the hydrolysis. This secondary reaction may also be carried out in solution or in a kneader.
When the reaction in this invention is carried out in a solvent, the reaction can be stopped, and the rubber can be coagulated 9 by pouring the reaction soul-lion into a large amount Or an alcohol or hot water with stirring. as required, the coagulated rubber is then washed to rove organic materials. Subsequent drying gives a modified rubber.
An unvulcanized compound obtained by mixing the resulting modified rubber with conventional rubber chemicals such as a reinforcing agent, a filler, a vulcanizer, a vulcanization accelerator, a vulcanization aid, a softening agent, a tackifier or an antioxidant exhibit excellent green strength. Vulcanized products of the compound have excellent strength properties such as tear strength. An unvulcanized compound of the modified rubber in which the ester group has been partly or wholly converted to a carboxyl group by the method described above is characterized by having higher green strength.
The kind Or the reinforcing agent to be blended with the modified rubber is not particularly limited.
Examples of preferred reinforcing agents include carbon blacks having an average particle diameter of 10 my to 500 my, for example channel blacks abbreviated as EPIC, MPC, HPC, CC, etc., furnace blacks abbreviated as SAFE
ISAF, HA, MA, FEZ, HMF, SURF, SPY, GPF, APP,-FF, OF, etc., thermal blacks abbreviated as FIT, MT, etc., and I
acetylene black; and silica-type reinforcing agents having an average particle diameter of 10 my to 100 my such as silicic android obtained by the dry method, hydrous silicic acid obtained by the wet method, and synthetic silicate salts.
Calcium carbonate, clay and talc may be used as the filler.
The amount of the reinforcing agent and/or the filler to be blended is usually 1 to 200 parts by weight, preferably 10 to 120 parts by weight, per 1~0 parts by weight of the modified rubber, selected depend-in upon the end use of the final product.
Sulfur and sulfur donors Or the thrum and thiazole series are typical vulcanizers. As required, peroxides, polyamides, metal oxides, urethane vulcanizers and resin vulcanizers may be used. Examples of the vulcanization accelerator may be those of the sulfonamide, thrum, thiazole, guanidine, mercaptotriazine, and aldehyde-amine series. Examples of the vulcanization aid are carboxylic acids such as Starkey acid and oleic acid, and metal compounds such as zinc Stewart, zinc oxide, magnesium oxide, calcium hydroxide and lead carbonate. Paraffinic, naphthenic and aromatic process oils may be used as the softening agent. Examples of the tackifier are rosin, petroleum hydrocarbon resins, Cameron resins and phenol-terpenene resins. Amine and phenols may be used as the antioxidant. The above-exemplified vulcanization accelerators and aids are used mainly for vulcanization with sulfur or sulfur donors.
The modified rubber obtained by the method ox this invention may be blended in any desired proportion with other rubbers such as natural rubber, styrenes butadiene copolymer rubber, polybutadiene rubber, and unmodified polyisoprene rubber.
The method of mixing the individual ingredients is not particularly limited, and usually, various types of rubber kneading machines are used. The carbon black sly and the process oil may be mixed with rubber in the step of producing the starting rubber or in the step of modifying the rubber to form a carbon master batch and an oil master batch.
Since a compound of the modified rubber obtained by the method of this invention has excellent green strength in the unvulcanized state and excellent dynamic properties such as tear strength, fatigue resistance and rebound after vulcanization, it is useful as the carcasses, treads, side walls, bead fillers and inner liners of vehicle tires, particularly large-sized tires for tracks and buses, various anti vibratory rubbers, industrial belts and hoses.
The modified rubber obtained by the method of this invention may also be formed into a latex and used in ordinary applications of lattices.
The following examples illustrate the present invention specifically.
Analysis of the modified rubber, preparation of the unvulcanized compound and the vulcanized product of the modified rubber, and testing of the properties of these materials in the examples were carried out by the following methods.
Ester group content of the rubber The modified rubber from which the remaining low-molecular-weight components were removed was sub-jetted to infrared absorption spectrometer. The content of the ester group introduced into the rubber was determined from the ratio between the absorption at 30 1720 - 1735 Cal due to the C=0 stretching vibration of the ester and the absorption at 1660 cm 1 due to the C=0 stretching vibration of the rubber.
Carboxyl group content of the rubber After the low-molecular-weight components were removed from the rubber, its carboxyl group content was measured by a neutralization titration method.
Amount of gel About 0.2 g of small pieces of a rubber sample were put in a square cage made of an Messiah wire gauze and measuring 3 cm at each side, and immersed for 24 hours in Tulane. The amount (%) of a gel was determined from the dry weight of the rubber remaining in the cage.
A gel content of 2% or below is considered to represent substantially no gellation.
Preparation of an unvulcanized compound of rubber The modified rubber was kneaded with the various compounding chemicals in the following recipe excepting sulfur and the vulcanization accelerator in a small-sized Banbur mixer. Sulfur and the vulcanize-` 15 lion accelerator were added to the resulting mixture one small roll and kneaded to prepare an unvulcanized rubber compound.
Compounding recipe:-Rubber (parts by weight) HA carbon 50 Aromatic process oil 5 Zinc oxide 5 Starkey acid 2 Sulfur 2.5 N-oxydiethylene-2-benzothiazyl sulfonamide (vulcanization accelerator) 0.8 N-isopropyl-N'-phenyl-p-phenylenediamine1.0 Wallace plasticity The plasticity of rubber or an unvulcanized rubber compound was measured at 100 C. by a Wallace's rapid plastometer.
Green strength The unvulcanized rubber compound was press-formed at 100 C for 5 minutes to form an unvulcanized rubber sheet having a thickness of' 2 mm. A dumbbell-shaped JIG No. 3 test specimen was punched out from Truly leak issue g the sheet. The test specimen was subjected to a tensile test at 25 C. at a tensile speed of 500 mm/min., and its tensile stress at 500% stretch was determined and defined as the green strength.
Vulcanization speed This is represented by the time (T95) which elapsed until the torque measured at 145 C by an oscillating disc remoter reached 95% of the maximum torque.
Tensile test An unvulcanized rubber compound was press-cured at 145 C for a predetermined period of time to form a 2 mm-thick sheet, and a Dumbell-shaped No. 3 test specimen stipulated in JIS-K6301 was punched out. The test specimen was subjected to a tensile test at a tensile speed of 500 mm/min. at 25 C.
Tear strength Six rectangular test specimens, each 15 mm wide and 100 mm long, were punched out from a 2 mm-thick vulcanized sheet. Three of the test specimens had a longitudinal direction corresponding with the grain direction, and the remaining three had a widths direction corresponding with the grain direction. In each test specimen, a cut, 6 mm long, was formed central-lye in one longitudinal side edge at right angles thereto by a safety razor blade. The tear strengths of the test specimens were measured at a tensile speed of 500 mm/min.
at 25 C, and the average of the six strength values was calculated.
Example 1 One hundred and sixty grams of polyisoprene rubber having a Swiss linkage content of 98% (sample A) was dissolved in 4 liters of dehydrated Nixon, and in a sealed glass vessels (separable flask), ethyl glyoxylate and Snuck were added in the amounts indicated in Table 1 to the solution at 25 C in an atmosphere of nitrogen, and the mixture was reacted for 60 minutes.
One hundred milliliters of methanol was poured into the reaction mixture (whereby it was presumed the addition-reaction was stopped). Thereafter, the reaction mixture was poured into acetone to coagulate the rubber complete-lye The coagulated product was cut to pieces and washed.
The small pieces of the rubber were then immersed in 3 liters of acetone containing about 2 g of 2,6-ditertiary butyl-4-methylphenol (antioxidant) and then dried for one day in a vacuum dryer. Thus, samples B, C, D and E shown in Table 1 were obtained.
It is seen that samples D and E in accordance with this invention were modified (introduction of the ester group) without substantial elysian and molecular weight reduction (change in the Wallace plasticity).
Table 1 Ester group _ EthylSnC14 introduced 11 Amount Sample glyoxyl~te into rubber We ace Of gel go (moles/100 g P Y (o/o) of rubber) _ _ Jo A _ _ _ 46 0.6 B 1.2 O O 48 0.2 C O 3.12 O 49 0.4 o' .
D 1.2 3.12 0.0059 49 0.4 E 2.4 6.25 0.0120 49 I
*This value was obtained with a rubber prepared by performing the same operation as in the preparation of the other samples except that ethyl glyoxylate and Snuck were not added to sample A, and is not the amount of gel originally contained in sample A (the gel which was originally contained in Sample A mostly disappeared when sample A was dissolved in Nixon).
The properties of unvulcanized compounds of the samples indicated in Table 1 and their vulcanization products were measured, and the results are shown in Table 2.
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12 _ It is seen from Table 2 that the samples D and E in accordance with this invention have excellent green strength and tear strength.
Example 2 The same polyisoprene rubber as used in Example 1 (160 g) was dissolved in 3 liters of dehydrated Tulane, and in a sealed glass vessel (separable flask), tertiary bottle glyoxylate and Snuck were added in the amounts indicated in Table 3 to the solution at 25 C in an atmosphere of nitrogen. The mixture was reacted for 30 minutes, and then 50 ml of methanol was poured into the reaction mixture (whereby it was presumed the addition-reaction was stopped). Then, the reaction mixture was poured into 3 liters of methanol to coagulate the rubber completely. The coagulated product was cut to small pieces and washed. The small rubber pieces were then immersed in 3 liters of methanol containing about
2 g of 2,6-ditertiary butyl-4-methylphenol (antioxidant), washed, and dried for a day in a vacuum dryer. Thus, samples F and G were obtained.
Table 3 , -- _ Ester group t-Butyl Snuck introduced Wallace Amount Sample glyoxylate go into rubber plasticity Of gel of rubber) _ _ _ .
F 0.76 1.52 0.0032 48 0.6 G 1.53 3.04 0.0060 46 Go Unvulcanized compounds of samples F and G and their vulcanization products were measured, and the results are shown in Table 4.
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,, I o _ Lo Jo joy to _ 14 -Example 3 The same polyisoprene rubber as used in Example 1 (160 g) was dissolved in 3 liters of dehydrated Bunsen, and in a sealed glass vessel (separable flaslc), tertiary bottle glyoxylate and Snuck were added in the amounts indicated in Table 5 to the solution at 25 C in an atmosphere of nitrogen. The mixture was reacted for 30 minutes and then 100 ml of methanol was poured into the reaction mixture whereby it was presumed the addition-reaction was stopped). Then, an aqueous solution of HClwas added in each of the amounts indicated in Table 5, and the mixture was stirred for 1 hour.
The reaction mixture was then poured into 3 liters of methanol to coagulate the rubber completely.
The coagulated product was cut to small pieces and washed. The small rubber pieces were immersed in 3 liters of methanol containing about 2 g of 2,6-ditertiary butyl-4-methylphenol antioxidant), washed, and dried for a day in a vacuum dryer to obtain samples H and I shown in Table 5.
Tubule _ Aqueous Carboxyl _ solution group t-Butyl of Hal introduced Wallace Sample glyoxylate Snuck (10%) into rubber plasticity (moles/100 g (g) (g) (g) of rubber) _ _ H 0.75 1.52 4.2 0.0016 45 I 1.50 3.04 8.5 0.0033 43 The properties of unvulcanized compounds of samples H and I and their vulcanization products were measured, and the results are shown in Table 6.
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_ 16 -It is seen from Table 6 that the green strengths of these samples H and I are higher than those of the samples shown in Table 4.
Example 4 -Polyisoprene rubber was modified in the same way as in Example 3 except that bouncily glyoxylate was used as the glyoxylate, and BF30(C2H5)2 (an ethyl ether complex of BF3) was used as the Lewis acid, in the amounts indicated in Table 7.
Sample J shown in Table 7 was obtained.
Table 7 Ester group _ Sample Bent into rubber plasticity ofm(g/~)lt of rubber) J 0.75 0.8 The properties of an unvulcanized compound of sample J and its vulcanization product were measured, and the results are shown in Table 8.
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_ o _ Jo Jo o _ of Example 5 Fifth grams of each of the unsaturated rubbers shown in Table 9 (polyisoprene rubber having a Swiss linkage content of 98%, polybutadiene rubber having a Swiss linkage content of 98%, and polybutadiene rubber having a vinyl linkage content of 70%) was dissolved in 1 liter of dehydrated Tulane, and in a sealed glass vessel (separable flask), each of the glyoxylate esters and each of the Lewis acids shown in Table 9 were added to the solution at 25 C in an atmosphere of nitrogen.
The mixture was reacted for 30 minutes, and then 30 ml of methanol was poured into the reaction mixture. Then, the reaction mixture was poured into 1 liter of methanol to coagulate the rubber completely. The coagulated products were cut to small pieces, and washed. Then, the small rubber pieces were immersed in 1 liter of methanol containing about 1 g of 2,6-ditertiary bottle-methyl phenol (antioxidant), washed, and then dried for a day in a vacuum dryer to obtain samples K to 0, Q to S, U and V shown in Table 9.
Samples K to 0, Q to S, U and V in accordance with this invention were modified without substantial gellation or molecular weight reduction. It is seen that the method of this invention is an excellent method of modifying unsaturated rubbers.
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Table 3 , -- _ Ester group t-Butyl Snuck introduced Wallace Amount Sample glyoxylate go into rubber plasticity Of gel of rubber) _ _ _ .
F 0.76 1.52 0.0032 48 0.6 G 1.53 3.04 0.0060 46 Go Unvulcanized compounds of samples F and G and their vulcanization products were measured, and the results are shown in Table 4.
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,, I o _ Lo Jo joy to _ 14 -Example 3 The same polyisoprene rubber as used in Example 1 (160 g) was dissolved in 3 liters of dehydrated Bunsen, and in a sealed glass vessel (separable flaslc), tertiary bottle glyoxylate and Snuck were added in the amounts indicated in Table 5 to the solution at 25 C in an atmosphere of nitrogen. The mixture was reacted for 30 minutes and then 100 ml of methanol was poured into the reaction mixture whereby it was presumed the addition-reaction was stopped). Then, an aqueous solution of HClwas added in each of the amounts indicated in Table 5, and the mixture was stirred for 1 hour.
The reaction mixture was then poured into 3 liters of methanol to coagulate the rubber completely.
The coagulated product was cut to small pieces and washed. The small rubber pieces were immersed in 3 liters of methanol containing about 2 g of 2,6-ditertiary butyl-4-methylphenol antioxidant), washed, and dried for a day in a vacuum dryer to obtain samples H and I shown in Table 5.
Tubule _ Aqueous Carboxyl _ solution group t-Butyl of Hal introduced Wallace Sample glyoxylate Snuck (10%) into rubber plasticity (moles/100 g (g) (g) (g) of rubber) _ _ H 0.75 1.52 4.2 0.0016 45 I 1.50 3.04 8.5 0.0033 43 The properties of unvulcanized compounds of samples H and I and their vulcanization products were measured, and the results are shown in Table 6.
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_ 16 -It is seen from Table 6 that the green strengths of these samples H and I are higher than those of the samples shown in Table 4.
Example 4 -Polyisoprene rubber was modified in the same way as in Example 3 except that bouncily glyoxylate was used as the glyoxylate, and BF30(C2H5)2 (an ethyl ether complex of BF3) was used as the Lewis acid, in the amounts indicated in Table 7.
Sample J shown in Table 7 was obtained.
Table 7 Ester group _ Sample Bent into rubber plasticity ofm(g/~)lt of rubber) J 0.75 0.8 The properties of an unvulcanized compound of sample J and its vulcanization product were measured, and the results are shown in Table 8.
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_ o _ Jo Jo o _ of Example 5 Fifth grams of each of the unsaturated rubbers shown in Table 9 (polyisoprene rubber having a Swiss linkage content of 98%, polybutadiene rubber having a Swiss linkage content of 98%, and polybutadiene rubber having a vinyl linkage content of 70%) was dissolved in 1 liter of dehydrated Tulane, and in a sealed glass vessel (separable flask), each of the glyoxylate esters and each of the Lewis acids shown in Table 9 were added to the solution at 25 C in an atmosphere of nitrogen.
The mixture was reacted for 30 minutes, and then 30 ml of methanol was poured into the reaction mixture. Then, the reaction mixture was poured into 1 liter of methanol to coagulate the rubber completely. The coagulated products were cut to small pieces, and washed. Then, the small rubber pieces were immersed in 1 liter of methanol containing about 1 g of 2,6-ditertiary bottle-methyl phenol (antioxidant), washed, and then dried for a day in a vacuum dryer to obtain samples K to 0, Q to S, U and V shown in Table 9.
Samples K to 0, Q to S, U and V in accordance with this invention were modified without substantial gellation or molecular weight reduction. It is seen that the method of this invention is an excellent method of modifying unsaturated rubbers.
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O. D _ f Example 6 One hundred and sixty (160) grams of pulse-prone rubber having a Swiss linkage content of 98%
(sample a) was dissolved in 3 liters of dehydrated Tulane, and in a sealed glass vessel (separable flask), deathly oxomalonate and Snuck were added in the amounts shown in Table 10 to the solution at 25 C in an atoms-phone of nitrogen. The mixture was reacted for 30 minutes, and 100 ml of methanol was poured into the reaction mixture (whereby it was presumed the addition-reaction was stopped). Then, the reaction mixture was poured into 3 liters of methanol to coagulate the rubber completely. The coagulated Product was cut to small pieces and washed. The small rubber pieces were immersed in 3 liters of methanol containing about 2 g of 2,6-ditertiary butyl-4-methylphenol (antioxidant), washed, and dried for a day in a vacuum dryer to give samples b, c, d and e shown in Table 10.
It is seen that the samples d and e in accord-ante with this invention were modified (introduction of the ester group) without substantial gellation or molecular weight reduction (change in Wallace plasticity).
Table 10 _ ester group _ _ Deathly Snuck introduced Wallace Amount Sample oxomalonate into rubber lastic-t Of gel (g) (g) (moles/100 g p 1 y (%) of rubber) _ .
Jo a _ _ _ 48 0.6 b 1.0 O O 48 0.2 c _ 1.7 _ 47 0.4 o d 1.0 1.7 0.0019 48 owe e 2.8 4 8 0.0034 - 0 6 *This value was obtained with a rubber prepared _ 22 -by performing the same operation as in the preparation of the other samples except that deathly oxomalonate and Snuck were not added to sample a, and is not the amount of gel originally contained in sample a (the gel which was originally contained in sample A mostly disappeared when sample a was dissolved in Tulane).
The properties of unvulcanized compound Of the samples shown in Table 10 and their vulcanization products were measured, and the results are shown in Table 11.
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It is seen from Table 11 that the samples d and e of this invention particularly have excellent green strength and tear strength.
Example 7 Polyisoprene rubber (sample a; 160 g) was disk solved in 3 litters of dehydrated Tulane, and in a sealed glass vessel (separable flask),diethyl oxomalonate and Snuck in the amounts indicated in Table 12 were added to the solution at 25 C in an atmosphere of nitrogen.
10 The mixture was reacted for 30 minutes, and 100 ml of methanol was poured into the reaction mixture (whereby it was presumed the addition-reaction was stopped).
Then, ammonium curium nitrate was added as an aqueous solution in each of the amounts shown in Table 12. The mixture was stirred for 1 hour. Then, the reaction mixture was poured into 3 liters of methanol to coagulate the rubber completely. The coagulated product was cut to small pieces and washed. The small rubber pieces were immersed in 3 liters of methanol containing about 2 g of 2,6-ditertiary butyl-4-methylphenol (antioxidant), washed and then dried for a day in a vacuum dryer. Thus, the modified polyisoprene rubber samples f and g shown in Table 12 were obtained.
Table 12 __ _ _ Ammonium Carboxyl group Deathly Snuck curium introduced Sample oxomalonate nitrate into rubber (g) (g) (Melissa g of rubber) __ _ f 1.0 1.7 7-7 0.0005 g 2.8 4.8 20.0 0.0009 _ . _ The properties of unvulcanized compounds of samples f and g and their vulcanization products were measured, and the results are shown in Table 13.
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-- - Jo comparison of the results shown in Table 13 with those shown in Tale 11 indicates that the samples f and g in accordance with this invention have higher green strength and tear strength than the unmodified polyisoprene rubber a and samples d and e of this invent lion (treatment with ammonium curium nitrate was not performed).
Example 8 Fifty grams of an unsaturated rubber (pulse-Perle rubber having a Swiss linkage content of go%
as sample h or polybutadiene rubber having a Swiss linkage content of 98% as sample n) was dissolved in 1 liter of dehydrated Tulane, and in a sealed lass vessel (separable flask), each of the oxomalonates and each of the Lewis acids indicated in Table 14 were added to the solution at 25 C in an atmosphere of nitrogen.
The mixture was reacted for 30 minutes, and 30 ml of methanol was poured into the reaction mixture. The reaction mixture was then poured into 1 liter of methanol to coagulate the rubber completely. The coagulated product was cut to small pieces and washed. Then, the small rubber pieces were immersed in 1 liter of methanol containing about 1 g of 2,6-ditertiary butyl-4-methyl-phenol (antioxidant), washed, and dried for a day in a vacuum dryer- Thus, samples i to m and o to q shown in Table 14 were obtained.
It is seen that the samples i to m and o to q in accordance with this invention were modified (intro-diction of the ester group) without substantial gellation or molecular weight reduction, and the method of this invention is an excellent method for modifying us-saturated rubbers.
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so a) I o Q. as - -I - - -_ 28 -*The amount of gel in sample h or n was obtained with a rubber prepared in the same way as in the prepare-lion of the other samples except that the oxomalonate and the Lewis acid were not added to sample h or n, and is not the amount of gel originally contained in sample h or n ( the gel contained originally in sample h or n mostly disappeared when it was dissolved in Tulane) Example 9 .
Fifty grams of polyisoprene rubber having a Swiss linkage content of 98% (sample h) was dissolved in 2 liters of dehydrated Nixon, and in a sealed glass vessel (separable flask), each of the organic compounds and each of the Lewis acids indicated in Table 15 were added to the solution at 25 C in an atmosphere of I nitrogen. The mixture was reacted for 60 minutes, and then 30 ml of methanol was poured into the reaction mixture. Then, the reaction mixture was poured into 2 liters of acetone to coagulate the rubber completely.
The coagulated product was cut to small pieces and washed. The small rubber pieces were immersed in 2 liters of methanol containing about 1 g of 2,6-ditertiary butyl_4-methylphenol (antioxidant), washed and dried Pro a day in a vacuum dryer. Thus, samples r to v were obtained.
A comparison of samples r to v in accordance with this invention with the unmodified sample h (see Table 14) shows that they were modified (introduction of the ester group) without substantial gellation or molecular weight reduction, and the method of this invent lion is an excellent method for modifying unsaturated rubbers.
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O. D _ f Example 6 One hundred and sixty (160) grams of pulse-prone rubber having a Swiss linkage content of 98%
(sample a) was dissolved in 3 liters of dehydrated Tulane, and in a sealed glass vessel (separable flask), deathly oxomalonate and Snuck were added in the amounts shown in Table 10 to the solution at 25 C in an atoms-phone of nitrogen. The mixture was reacted for 30 minutes, and 100 ml of methanol was poured into the reaction mixture (whereby it was presumed the addition-reaction was stopped). Then, the reaction mixture was poured into 3 liters of methanol to coagulate the rubber completely. The coagulated Product was cut to small pieces and washed. The small rubber pieces were immersed in 3 liters of methanol containing about 2 g of 2,6-ditertiary butyl-4-methylphenol (antioxidant), washed, and dried for a day in a vacuum dryer to give samples b, c, d and e shown in Table 10.
It is seen that the samples d and e in accord-ante with this invention were modified (introduction of the ester group) without substantial gellation or molecular weight reduction (change in Wallace plasticity).
Table 10 _ ester group _ _ Deathly Snuck introduced Wallace Amount Sample oxomalonate into rubber lastic-t Of gel (g) (g) (moles/100 g p 1 y (%) of rubber) _ .
Jo a _ _ _ 48 0.6 b 1.0 O O 48 0.2 c _ 1.7 _ 47 0.4 o d 1.0 1.7 0.0019 48 owe e 2.8 4 8 0.0034 - 0 6 *This value was obtained with a rubber prepared _ 22 -by performing the same operation as in the preparation of the other samples except that deathly oxomalonate and Snuck were not added to sample a, and is not the amount of gel originally contained in sample a (the gel which was originally contained in sample A mostly disappeared when sample a was dissolved in Tulane).
The properties of unvulcanized compound Of the samples shown in Table 10 and their vulcanization products were measured, and the results are shown in Table 11.
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It is seen from Table 11 that the samples d and e of this invention particularly have excellent green strength and tear strength.
Example 7 Polyisoprene rubber (sample a; 160 g) was disk solved in 3 litters of dehydrated Tulane, and in a sealed glass vessel (separable flask),diethyl oxomalonate and Snuck in the amounts indicated in Table 12 were added to the solution at 25 C in an atmosphere of nitrogen.
10 The mixture was reacted for 30 minutes, and 100 ml of methanol was poured into the reaction mixture (whereby it was presumed the addition-reaction was stopped).
Then, ammonium curium nitrate was added as an aqueous solution in each of the amounts shown in Table 12. The mixture was stirred for 1 hour. Then, the reaction mixture was poured into 3 liters of methanol to coagulate the rubber completely. The coagulated product was cut to small pieces and washed. The small rubber pieces were immersed in 3 liters of methanol containing about 2 g of 2,6-ditertiary butyl-4-methylphenol (antioxidant), washed and then dried for a day in a vacuum dryer. Thus, the modified polyisoprene rubber samples f and g shown in Table 12 were obtained.
Table 12 __ _ _ Ammonium Carboxyl group Deathly Snuck curium introduced Sample oxomalonate nitrate into rubber (g) (g) (Melissa g of rubber) __ _ f 1.0 1.7 7-7 0.0005 g 2.8 4.8 20.0 0.0009 _ . _ The properties of unvulcanized compounds of samples f and g and their vulcanization products were measured, and the results are shown in Table 13.
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-- - Jo comparison of the results shown in Table 13 with those shown in Tale 11 indicates that the samples f and g in accordance with this invention have higher green strength and tear strength than the unmodified polyisoprene rubber a and samples d and e of this invent lion (treatment with ammonium curium nitrate was not performed).
Example 8 Fifty grams of an unsaturated rubber (pulse-Perle rubber having a Swiss linkage content of go%
as sample h or polybutadiene rubber having a Swiss linkage content of 98% as sample n) was dissolved in 1 liter of dehydrated Tulane, and in a sealed lass vessel (separable flask), each of the oxomalonates and each of the Lewis acids indicated in Table 14 were added to the solution at 25 C in an atmosphere of nitrogen.
The mixture was reacted for 30 minutes, and 30 ml of methanol was poured into the reaction mixture. The reaction mixture was then poured into 1 liter of methanol to coagulate the rubber completely. The coagulated product was cut to small pieces and washed. Then, the small rubber pieces were immersed in 1 liter of methanol containing about 1 g of 2,6-ditertiary butyl-4-methyl-phenol (antioxidant), washed, and dried for a day in a vacuum dryer- Thus, samples i to m and o to q shown in Table 14 were obtained.
It is seen that the samples i to m and o to q in accordance with this invention were modified (intro-diction of the ester group) without substantial gellation or molecular weight reduction, and the method of this invention is an excellent method for modifying us-saturated rubbers.
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Fifty grams of polyisoprene rubber having a Swiss linkage content of 98% (sample h) was dissolved in 2 liters of dehydrated Nixon, and in a sealed glass vessel (separable flask), each of the organic compounds and each of the Lewis acids indicated in Table 15 were added to the solution at 25 C in an atmosphere of I nitrogen. The mixture was reacted for 60 minutes, and then 30 ml of methanol was poured into the reaction mixture. Then, the reaction mixture was poured into 2 liters of acetone to coagulate the rubber completely.
The coagulated product was cut to small pieces and washed. The small rubber pieces were immersed in 2 liters of methanol containing about 1 g of 2,6-ditertiary butyl_4-methylphenol (antioxidant), washed and dried Pro a day in a vacuum dryer. Thus, samples r to v were obtained.
A comparison of samples r to v in accordance with this invention with the unmodified sample h (see Table 14) shows that they were modified (introduction of the ester group) without substantial gellation or molecular weight reduction, and the method of this invent lion is an excellent method for modifying unsaturated rubbers.
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Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for modifying a rubber, which comprises re-acting a rubber having an unsaturated carbon bond with an organic compound represented by the general formula wherein -R represents a hydrocarbon group, and -X
represents -H, -CN or -?-Y in which Y represents -R1, -OR2 or -NR3R4 in which -R1, -R2, -R3 and -R4 are hydro-carbon groups, in the presence of a Lewis acid to introduce an ester group.
represents -H, -CN or -?-Y in which Y represents -R1, -OR2 or -NR3R4 in which -R1, -R2, -R3 and -R4 are hydro-carbon groups, in the presence of a Lewis acid to introduce an ester group.
2. The method of claim 1 wherein the rubber having an un-saturated carbon bond is polyisoprene rubber.
3. The method of claim 1 wherein the Lewis acid is SnCl4, BF3O(C2H5)2 or TiCl4.
4. The method of claim 1 wherein -R, -R1, -R2, -R3 and -R4 in the general formula represents an aliphatic, alicyclic or aro-matic hydrocarbon group.
5. The method of claim 1 wherein when -X in the general formula is -?-Y, -Y represents -R1, -OR2 or -NH3R4 in which R1, -R2, -R3 and -R4 are hydrocarbon groups.
6. A method for modifying a rubber, which comprises re-acting a rubber having an unsaturated carbon bond with an organic compound represented by the general formula wherein -R represents a hydrocarbon group, and -X
is -H, -CN or -?-Y in which -Y represents -Rl, -OR2 or -NR3R4 in which -Rl, -R2, -R3 and -R4 are hydrocarbon groups, in the presence of a Lewis acid to introduce an ester group, and thereafter converting the ester group either partly or wholly into a carboxyl group by chemical treatment.
is -H, -CN or -?-Y in which -Y represents -Rl, -OR2 or -NR3R4 in which -Rl, -R2, -R3 and -R4 are hydrocarbon groups, in the presence of a Lewis acid to introduce an ester group, and thereafter converting the ester group either partly or wholly into a carboxyl group by chemical treatment.
7. The method of claim 6 wherein the rubber having an un-saturated carbon bond is polyisoprene rubber.
8. The method of claim 6 wherein the Lewis acid is SnC14, BF3O(C2H5)2, or TiCl4
9. The method of claim 6 wherein -R, -R1, -R2, -R3 and -R4 in the general formula is an aliphatic, alicyclic or aromatic hydrocarbon group.
10. The method of claim 6 wherein when -X in the general formula is -?-Y, -Y is -R1, -OR2, or -NR3R4 in which -R1, -R2, -R3 and -R4 are hydrocarbon groups.
11. The method of claim 6 wherein the chemical treatment is carried out in the presence of an acid, an alkali, or a radical generator.
12. A modified rubber obtained by reacting a rubber having an unsaturated carbon bond with an organic compound represented by the general formula wherein -R represents a hydrocarbon group, and -X
represents -H, -CN or -?-Y in which Y represents -R1, -OR2 or -NR3R4 in which -R1, -R2, -R3 and -R4 are hydro-carbon groups, in the presence of a Lewis acid to introduce an ester group.
represents -H, -CN or -?-Y in which Y represents -R1, -OR2 or -NR3R4 in which -R1, -R2, -R3 and -R4 are hydro-carbon groups, in the presence of a Lewis acid to introduce an ester group.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11214582A JPS591502A (en) | 1982-06-29 | 1982-06-29 | Modification of rubber |
| JP112,145/82 | 1982-06-29 | ||
| JP37,159/83 | 1983-03-07 | ||
| JP3715983A JPS59161403A (en) | 1983-03-07 | 1983-03-07 | Modification of rubber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1217598A true CA1217598A (en) | 1987-02-03 |
Family
ID=26376244
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000430823A Expired CA1217598A (en) | 1982-06-29 | 1983-06-21 | Method for modifying rubbers |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4525541A (en) |
| EP (1) | EP0099478B1 (en) |
| CA (1) | CA1217598A (en) |
| DE (1) | DE3362284D1 (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0651726B2 (en) * | 1985-03-29 | 1994-07-06 | 日本ゼオン株式会社 | Rubber modification method |
| US5646098A (en) * | 1990-07-23 | 1997-07-08 | Exxon Chemical Patents Inc | Carbonyl containing compounds and their derivatives as multi-functional fuel and lube additives |
| US5274051A (en) * | 1992-11-05 | 1993-12-28 | Exxon Research & Engineering Company | Carbonyl containing compounds via radical grafting |
| US5777142A (en) * | 1995-08-22 | 1998-07-07 | The Lubrizol Corporation | Unsaturated hydroxycarboxylic compounds useful as intermediates for preparing lubricant and fuel additives |
| SG64399A1 (en) * | 1995-08-22 | 1999-04-27 | Lubrizol Corp | Process for preparing compositions useful as intermediates for preparing lubricanting oil and fuel additives |
| US6020500A (en) * | 1995-08-22 | 2000-02-01 | The Lubrizol Corporation | Hydroxy-substituted monolactones useful as intermediates for preparing lubricating oil and fuel additives |
| US5840920A (en) | 1996-08-08 | 1998-11-24 | The Lubrizol Corporation | Process for preparing compositions useful as intermediates for preparing lubricating oil and fuel additives |
| US5779742A (en) * | 1996-08-08 | 1998-07-14 | The Lubrizol Corporation | Acylated nitrogen compounds useful as additives for lubricating oil and fuel compositions |
| US6117941A (en) * | 1997-06-05 | 2000-09-12 | The Lubrizol Corporation | Intermediates useful for preparing dispersant-viscosity improvers for lubricating oils |
| US6288013B1 (en) * | 1997-12-03 | 2001-09-11 | The Lubrizol Corporation | Nitrogen containing dispersant-viscosity improvers |
| US20010036993A1 (en) * | 1999-08-27 | 2001-11-01 | Mcnutt Jamie J. | Large sized carbon black particles to reduce needed mixing energy of high hardness, stiff tire compositions |
| US7087558B2 (en) | 2000-05-18 | 2006-08-08 | The Lubrizol Corporation | Process for reacting large hydrophobic molecules with small hydrophilic molecules |
| MX2010011299A (en) * | 2008-04-14 | 2010-11-12 | Bridgestone Corp | Processes for recovering rubber from natural rubber latex. |
| CN104271606B (en) | 2012-03-06 | 2019-07-09 | 株式会社普利司通 | For collecting the method for rubber from aged briquetting and comprising the aged briquetting of the plant material from non-para-caoutchouc plant |
| WO2013173625A1 (en) | 2012-05-16 | 2013-11-21 | Bridgestone Corporation | Compositions containing purified non-hevea rubber and related purification methods |
| WO2013192227A1 (en) | 2012-06-18 | 2013-12-27 | Bridgestone Corporation | Methods for desolventization of bagasse |
| CN104395350B (en) | 2012-06-18 | 2017-07-14 | 株式会社普利司通 | The system and method for the waste related for the guayule shrub processing for managing to extracting rubber |
| US10138304B2 (en) | 2012-06-18 | 2018-11-27 | Bridgestone Corporation | Methods for increasing the extractable rubber content of non-Hevea plant matter |
| US9567457B2 (en) | 2013-09-11 | 2017-02-14 | Bridgestone Corporation | Processes for the removal of rubber from TKS plant matter |
| US10775105B2 (en) | 2018-11-19 | 2020-09-15 | Bridgestone Corporation | Methods for the desolventization of bagasse |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE644223A (en) * | 1963-02-27 | 1964-06-15 | ||
| US3478004A (en) * | 1967-04-26 | 1969-11-11 | Grace W R & Co | Crosslinking polyolefins with selected dioxime diesters |
| US3652520A (en) * | 1968-03-22 | 1972-03-28 | Atlantic Richfield Co | Polymers of polymerizable polydiene ethylenically unsaturated esters |
| US3803087A (en) * | 1971-08-03 | 1974-04-09 | Dow Chemical Co | Process for preparing modified polymers |
| FR2265773B1 (en) * | 1974-03-29 | 1977-09-30 | Inst Francais Du Petrole | |
| US4173552A (en) * | 1974-08-12 | 1979-11-06 | The C. P. Hall Company | Rubber additives |
| US4144226A (en) * | 1977-08-22 | 1979-03-13 | Monsanto Company | Polymeric acetal carboxylates |
| US4228254A (en) * | 1978-08-07 | 1980-10-14 | Exxon Research & Engineering Co. | Functional group containing cyclic diolefin butyl rubbers |
| JPS5950191B2 (en) * | 1978-11-14 | 1984-12-06 | 三井化学株式会社 | Hot melt adhesive composition |
| CA1135712A (en) * | 1979-05-29 | 1982-11-16 | Peter J. Schirmann | Activated ester monomers and polymers |
-
1983
- 1983-06-21 EP EP83106045A patent/EP0099478B1/en not_active Expired
- 1983-06-21 CA CA000430823A patent/CA1217598A/en not_active Expired
- 1983-06-21 DE DE8383106045T patent/DE3362284D1/en not_active Expired
- 1983-06-22 US US06/506,875 patent/US4525541A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| US4525541A (en) | 1985-06-25 |
| EP0099478B1 (en) | 1986-02-26 |
| EP0099478A3 (en) | 1984-03-28 |
| DE3362284D1 (en) | 1986-04-03 |
| EP0099478A2 (en) | 1984-02-01 |
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