CN102858805A - Method for producing modified natural rubber - Google Patents
Method for producing modified natural rubber Download PDFInfo
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- CN102858805A CN102858805A CN2011800120188A CN201180012018A CN102858805A CN 102858805 A CN102858805 A CN 102858805A CN 2011800120188 A CN2011800120188 A CN 2011800120188A CN 201180012018 A CN201180012018 A CN 201180012018A CN 102858805 A CN102858805 A CN 102858805A
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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
- C08C19/04—Oxidation
- C08C19/06—Epoxidation
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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
- C08C1/00—Treatment of rubber latex
- C08C1/02—Chemical or physical treatment of rubber latex before or during concentration
- C08C1/04—Purifying; Deproteinising
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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
- C08C2/00—Treatment of rubber solutions
- C08C2/02—Purification
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L15/00—Compositions of rubber derivatives
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Abstract
Disclosed is a method for producing modified natural rubber, comprising an epoxidation step, a removal step, and a reduction and ring-opening step. In the epoxidation step, in a latex in which a plant-derived rubbery polymer having a plurality of unsaturated double bonds in the main chain is dispersed in water serving as a dispersion medium, an organic peracid is reacted with the rubbery polymer. In this manner, by the epoxidation of a part of the unsaturated double bonds in the rubbery polymer, an epoxidated rubbery polymer is obtained. In the removal step, organic peracid-derived substances generated from the organic peracid in the epoxidation step are removed from the latex, whereby the content of the organic peracid-derived substances in the latex is reduced to 35 parts by mass or less based on 100 parts by mass of the epoxidated rubbery polymer. In the reduction and ring-opening step, under the conditions of pH 7 to 8 and in the presence of an organic acid salt, a part or the whole of the remaining unsaturated double bonds in the epoxidated rubbery polymer in the latex are reduced, and also a part or the whole of the epoxy groups in the epoxidated rubbery polymer are ring-opened.
Description
Technical field
The present invention relates to the manufacture method of modified natural rubber, the manufacture method of the modified natural rubber that the manufacturing process after can making epoxidation process simplifies.
Background technology
All the time, rubber item has been applied to various fields.The raw material of rubber item is divided into the natural rubber that comes from plant and the synthetic rubber that comes from oil.In synthetic rubber, the various synthetic rubber of the excellences such as oil-proofness, weathering resistance, gas-premeable, winter hardiness are actually used.For example, as the synthetic rubber of weathering resistance and ozone resistance excellence, can enumerate ethylene-propylene rubber(EPR) (EPDM).This synthetic rubber is used to the purposes such as trolley part, isolator.
In recent years, people exist the exhaustion of petroleum resources and global warming etc. and worry.Therefore, as the equivalent material of the material that comes from oil, more and more higher to the concern of the material that comes from plant.For the material that comes from plant, expect it except the consumption that suppresses limited petroleum resources, also because understanding absorbing carbon dioxide in process of growth, plant suppress global warming.The natural rubber (rubbery polymer) that comes from plant with the form collection of polymkeric substance from rubber tree.The excellences such as the processibility of natural rubber and intensity.On the other hand, the weathering resistance of natural rubber and ozone resistance are poor.Therefore, in order to improve rubber property and to give rubber new features etc., attempted the modification of various natural rubbers.In addition, in order to improve the scope of application and convenience, various modified natural rubbers have been developed.
Thereby patent documentation 1 discloses a kind of with the unsaturated double-bond in main chain reduction and make unsaturated double-bond reduce, make simultaneously a part of epoxidation of unsaturated double-bond and the modified natural rubber that open loop imports hydroxyl.Disclosed modified natural rubber in this document is because unsaturated double-bond reduces, so weathering resistance and ozone resistance are excellent.And therefore disclosed modified natural rubber in the document is cross-linked to form the ability excellence owing to imported hydroxyl.The modified natural rubber that obtains like this be applicable to (such as) automobile such as riband having the local parts that use of water with frame members, hose etc.
The prior art document
Patent documentation
Patent documentation 1: TOHKEMY 2008-308601 communique
Summary of the invention
Invent problem to be solved
As the method for being made modified natural rubber by above-mentioned rubbery polymer, can use following methods, thereby wherein said modified natural rubber is for making the reduction of the unsaturated double-bond in the main chain unsaturated double-bond to reduce, make simultaneously a part of epoxidation of unsaturated double-bond and the modified natural rubber that open loop imports hydroxyl.At first, in epoxidation process, add organic peracid in the latex that forms to rubbery polymer is scattered in water, make a part of unsaturated double-bond epoxidation on the rubbery polymer main chain, thereby generate the epoxidezed rubber shaped polymer.Then, in the reductive ring open operation, in the presence of hydrogenation catalyst, in the epoxidezed rubber shaped polymer, add hydrogen, make the epoxy ring-opening on the main chain, with remaining unsaturated double-bond reduction, generate thus modified natural rubber simultaneously.And, the modified natural rubber in the reaction solution after the open loop reduction operation is solidified, and separates and make with extra care.Obtain thus the solid state modification natural rubber.
In the reductive ring open operation, as the material of the organic peracid that adds in the derived from epoxidized operation, organic acid and organic acid salt thereof are present in the reaction system sometimes in a large number.In this case, cyclisation might occur or form the side reaction of not expecting such as crosslinked in the epoxidezed rubber shaped polymer, thereby loses rubber property.Thus, traditionally after epoxidation process, solidify by making the epoxidezed rubber shaped polymer in the latex, and it is separated from dispersion medium, thereby make epoxidezed rubber shaped polymer and separating substances derived from organic peracid.Then, make epoxidezed rubber shaped polymer redispersion after the curing in dispersion medium or be dissolved in the organic solvent, gains are processed in the reductive ring open operation.Like this, in traditional manufacture method, between epoxidation process and reductive ring open operation, need to carry out separating treatment and the redispersion of epoxidezed rubber shaped polymer and process or dissolution process.Therefore, manufacturing process is complicated.
The purpose of this invention is to provide a kind of manufacture method that can make the modified natural rubber of manufacturing process's simplification.
The means of dealing with problems
In order to achieve the above object, according to the first embodiment of the present invention, a kind of manufacture method of modified natural rubber is provided, this manufacture method has: epoxidation process, wherein, be scattered in the latex that forms as the water of dispersion medium at the rubbery polymer derived from plant that main chain is had a plurality of unsaturated double-bonds, make the reaction of organic peracid and rubbery polymer, a part of unsaturated double-bond initial ring oxidation of rubbery polymer obtains the epoxidezed rubber shaped polymer thus; Remove operation, wherein, from latex, remove in epoxidation process the material derived from organic peracid that is generated by organic peracid, the content derived from the material of organic peracid is reduced to below 35 mass parts with respect to 100 mass parts epoxidezed rubber shaped polymers; And reductive ring open operation, wherein, be under 7 to 8 the condition at pH, and in the presence of organic acid salt, part or all of residual unsaturated double-bond is reduced in the epoxidezed rubber shaped polymer in the latex, and open loop occurs for part or all of the epoxy group(ing) of epoxidezed rubber shaped polymer simultaneously.
In the manufacture method of above-mentioned modified natural rubber, in removing operation, preferably the part that is dissolved with derived from the dispersion medium of the material of organic peracid in the latex is replaced with new dispersion medium.
In the manufacture method of above-mentioned modified natural rubber, in removing operation, preferably by the latex behind the epoxidation process is carried out centrifuging treatment, the upper strata that latex is separated into mainly be dispersed with the epoxidezed rubber shaped polymer and mainly be dissolved with lower floor derived from the material of organic peracid, and, except in the sub-cloud, the upper strata is added new dispersion medium.
In formation of above-mentioned each invention, after epoxidation process, from latex, remove the material derived from organic peracid, thereby make the epoxidezed rubber shaped polymer with derived from the separating substances of organic peracid.That is, do not need to carry out as traditionally described, from latex, the epoxidezed rubber shaped polymer solidified and separates and refining, then make the epoxidezed rubber shaped polymer redispersion of curing to become the such operation of latex shape.Separating treatment and the redispersion that thus, can be omitted in the epoxidezed rubber shaped polymer that carries out between epoxidation process and the reductive ring open operation are processed.Therefore, can simplify manufacturing process behind the epoxidation process.In addition, can from latex, not separate and refining epoxidezed rubber shaped polymer, and directly carry out continuously epoxidation process and reductive ring open operation with the latex state.Improved thus the working efficiency when making.
In the manufacture method of above-mentioned modified natural rubber, in removing operation, preferably in the material of removing derived from organic peracid, remove the glue protein of milk.
Gathering from the natural rubber latex Ruzhong of plant, except rubbery polymer, also contain range protein.When making modified natural rubber take this natural rubber latex that is mixed with protein as raw material, the unstable or poor quality of physical property that might resulting modified natural rubber.Therefore, be raw material when making modified natural rubber with being mixed with protein-free natural rubber latex, expectation be that the deproteinated that removes deproteinize is processed.
According to above-mentioned formation, in removing operation, in the material of removing derived from organic peracid, also except deproteinize.Thus, even when in a series of manufacturing process, also having carried out the deproteinated processing, do not need to append the operation for separating of rubber constituent and protein yet.Therefore, the increase of workload can be suppressed at bottom line.
In the manufacture method of above-mentioned modified natural rubber, in the reductive ring open operation, preferably, hydrogen atom is added on the unsaturated double-bond residual in the epoxidezed rubber shaped polymer, simultaneously with the epoxy ring-opening of epoxidezed rubber shaped polymer, thereby form hydroxyl.
The effect of invention
According to the present invention, the manufacturing process of modified natural rubber is simplified.
Embodiment
The below is elaborated to an embodiment, and this embodiment is specialized the manufacture method of the modified natural rubber that the present invention relates to.
In the manufacture method of the modified natural rubber of the present embodiment, used the rubbery polymer that comes from plant that has a plurality of unsaturated double-bonds on the main chain to be raw material.Then, the reduction of the unsaturated double-bond on the main chain so that unsaturated double-bond reduces, is made simultaneously a part of unsaturated double-bond epoxidation and open loop, thereby makes the modified natural rubber that has imported hydroxyl.The manufacture method of the modified natural rubber of the present embodiment comprises epoxidation process, removes operation and reductive ring open operation.In epoxidation process, will have a part of unsaturated double-bond epoxidation derived from the rubbery polymer of plant of a plurality of unsaturated double-bonds on the main chain, thereby obtain the epoxidezed rubber shaped polymer.In removing operation, with generate in the epoxidation process, remove derived from the material of organic peracid.In the reductive ring open operation, with part or all reduction of unsaturated double-bond residual in the epoxidezed rubber shaped polymer, make simultaneously part or all generation open loop of the epoxy group(ing) of epoxidezed rubber shaped polymer.
＜raw material 〉
As raw material, can use such natural rubber latex, it contains the rubbery polymer derived from plant that has a plurality of (more than 2) unsaturated double-bond at main chain.Particularly, can use the fresh latex that obtains from natural rubber tree and fresh latex processed after processed goods.As processed goods, for example, can enumerate fresh latex concentratedly having improved the latex of rubbery polymer concentration, fresh latex is carried out ammonia treatment and the latex that obtains, fresh latex is carried out that deproteinated is processed and the latex that obtains, and their mixture.In addition, as raw material, can also use the solid rubber that obtains from natural rubber latex Ruzhong separation and purification rubbery polymer.
As the method that deproteinated is processed, for example can enumerate the known method of putting down in writing in Unexamined Patent 6-56902 communique and the JP 2004-99696 communique.In deproteinated is processed, preferably, with respect to 100 mass parts rubbery polymers, the nitrogen content in natural rubber latex Ruzhong is set as below 0.1 mass parts, more preferably be set as below 0.05 mass parts.
＜epoxidation process 〉
Epoxidation process is such operation: make the reaction of organic peracid and rubbery polymer, a part of unsaturated double-bond on the rubbery polymer main chain is replaced into epoxy group(ing), thereby obtains the epoxidezed rubber shaped polymer.Particularly, at first, make as the natural rubber latex of raw material or solid rubber to be scattered in the water as dispersion medium preparation feedback type latex.Here, in order to distinguish with natural rubber latex, the latex that uses in the manufacturing process is recited as response type latex.At this moment, for the dispersion state that makes rubbery polymer is stable, preferably in dispersion medium, add tensio-active agent.
Water as dispersion medium can also contain water composition in addition, for example hydrophilic organic solvent on a small quantity.As tensio-active agent, can suitably use: anionic surfactant so lauryl sulfate, but be not limited to this, can also use the anion surfactants such as carboxylic acid type, sulfonic acid type, sulfuric acid ester type, phosphate type, the nonionic surface active agent such as polyethylene glycols or polyalcohols, the cationic surfactants such as quaternary ammonium salt, the amphotericses such as amino acids or betaines come from the Bio-surfactant of plant etc.
Next, make the rubbery polymer reaction in organic peracid and the prepared response type latex, carry out epoxidation.As organic peracid, can enumerate (for example) peroxybenzoic acid, peracetic acid, peroxyformic acid, adjacent carboxyl peroxybenzoic acid, Perpropionic Acid, trifluoro Peracetic Acid and Perbutyric Acid.These organic peracids can directly add in the response type latex.As diverse ways therewith, also can add the composition that can generate organic peracid, in response type latex, generate organic peracid.For example, when generating peroxyformic acid, can add formic acid in order and hydrogen peroxide gets final product.When generating peracetic acid, can add anhydrous acetic acid in order and hydrogen peroxide gets final product.
After adding organic peracid and having passed through the scheduled time, the alkali such as use ammonia soln carry out neutralizing treatment to response type latex.This moment, the organic peracid and the organic acid that exist in the response type latex were neutralized by neutralization reaction, generated organic peracid and organic acid salt.For example, be peracetic acid and when using ammonia soln to carry out neutralizing treatment at organic peracid, generated acetic acid by peracetic acid, by will containing the response type latex neutralization of acetic acid, thereby generate ammonium acetate.
Preferably carry out epoxidation reaction so that the epoxy rate of resultant epoxidezed rubber polymkeric substance in the scope of 1-25%.The epoxy rate of epoxidezed rubber polymkeric substance can be by changing organic peracid addition and treatment time etc. regulate.The epoxy rate of epoxidezed rubber polymkeric substance can be calculated by following formula." double key number of rubber polymer " in the formula (numerical value before the epoxidation) and " number of the epoxy group(ing) of epoxidezed rubber polymkeric substance " can be obtained by the measurement result of (for example) 1H-NMR.
[mathematical expression 1]
＜remove operation 〉
Remove operation for the response type latex behind epoxidation process, will remove as organic acid and organic acid salt derived from the material of organic peracid, so that the operation that their concentration reduces.In removing operation, make being reduced to below 35 mass parts with respect to 100 mass parts epoxidezed rubber polymkeric substance derived from the organic acid of organic peracid and the total content of salt thereof in the response type latex, preferably be down to below 30 mass parts, more preferably be down to below 25 mass parts.
As the method for from response type latex, removing derived from the material of organic peracid, for example can use centrifuging treatment.Particularly, by the response type latex behind the epoxidation process is carried out centrifuging treatment, response type latex can be separated into the upper and lower (lock out operation).The upper strata is the layer of latex shape (emulsus), wherein mainly is dispersed with the epoxidezed rubber shaped polymer with high density.Lower floor is aqueous layer, wherein mainly is dissolved with the material derived from organic peracid.For example, if carry out several about 10 minutes centrifuging treatments with the rotating speed of 5000 ~ 15000G, then can be as mentioned above such separating reaction type latex.
Next, when reclaiming the upper strata, in this upper strata, add dispersion medium (redispersion operation).Composition when the dispersion medium that adds in the redispersion operation can be with epoxidation process is identical, also can be different.By the operation of lock out operation and redispersion, the dispersion medium that is dissolved with in the response type latex derived from the material of organic peracid is replaced with new dispersion medium.Reduced thus the concentration derived from the material of organic peracid.In this case, depend in the response type latex after the redispersion operation derived from the concentration of the material of organic peracid, preferably repeat lock out operation and redispersion operation more than 2 times.
In addition, when using the natural rubber latex processed without deproteinated as raw material, in removing operation, also can carry out simultaneously deproteinated and process.Particularly, add protein denaturant in the response type latex before the centrifuging treatment, make the protein denaturation in the response type latex.Carry out centrifuging treatment under the state of protein denaturation, the protein transduction in the response type latex moves on to the liquid lower floor that has derived from the material of organic peracid.Thus, by the separation of the upper and lower, in the material of removing derived from organic peracid, can also remove the protein after the sex change.As protein denaturant, for example can enumerate by the represented urea compound of following general formula (1) (urea derivative, urea double salt) and clorox.As by the represented urea compound of following general formula (1), can enumerate (for example) urea, MU, ethyl carbamide, n-propyl urea, sec.-propyl urea, normal-butyl urea, isobutyl-urea and n-pentyl urea.Wherein particularly preferably urea, MU and ethyl carbamide.
RNHCONH
2…（1）
(R in the formula represents the alkyl of H or carbon number 1 to 5)
In the situation of carrying out the deproteinated processing, with respect to the epoxidezed rubber shaped polymer of 100 mass parts, the nitrogen content in the response type latex preferably is set to below 0.1 mass parts, more preferably is set to below 0.05 mass parts.
＜reductive ring open operation 〉
The reductive ring open operation is such operation: in part or all reduction of residual unsaturated double-bond, make part or all generation open loop of the epoxy group(ing) of epoxidezed rubber shaped polymer in the epoxidezed rubber shaped polymer in the response type latex.As the reduction of the unsaturated double-bond of epoxidezed rubber shaped polymer and the ring-opening reaction of epoxy group(ing) (hereinafter referred to as the reductive ring open reaction), can use the known method of reducing and the open-loop method that under the latex state, carry out.
In the case, the pH regulator in the time of reductive ring open need to being reacted is to stated limit.That is, the pH when reductive ring open reacts departs from 7 to 8 scope and when moving to acidic side or alkaline side, the cyclisation of the epoxidezed rubber shaped polymer in the time of can exceedingly promoting the reductive ring open reaction etc.Therefore, even in the situation that adopts either method, also need under the condition of pH7 to 8 and in the presence of organic acid salt, promote the reductive ring open reaction.Organic acid salt is by being dissolved in the effect of playing damping fluid in the water as the dispersion medium of response type latex.The larger variation of pH when therefore, organic acid salt can suppress the reductive ring open reaction.
As organic acid salt, can enumerate (such as) sodium salt, sylvite, calcium salt, amine salt (primary amine is to tertiary amine) and the ammonium salt of the carboxylic acid such as phenylformic acid, acetic acid, formic acid, phthalic acid, propionic acid, trifluoroacetic acid and butyric acid.Organic acid salt can not be removed, residues in the organic acid salt derived from organic peracid in the response type latex in removing operation, can be the organic acid salt that reacts stylish interpolation at reductive ring open yet.With respect to 100 mass parts epoxidezed rubber polymkeric substance, the content of the organic acid salt during the reductive ring open reaction is preferably 0.1 to 35 mass parts, more preferably 1.7 to 25 mass parts.
As the above-mentioned known method of reducing and the open-loop method that under the latex state, carry out, can enumerate (for example) in the presence of hydrogenation catalyst, the method that hydrogen is contacted with the epoxidezed rubber shaped polymer.Below, describe as the situation that reductive ring open reacts using the method that hydrogen is contacted with the epoxidezed rubber shaped polymer.
At first, in the response type latex of removing after the operation, add hydrogenation catalyst, with the pH regulator to 7 of the response type latex scope to 8.At this, when not containing the organic acid salt derived from organic peracid in the response type latex after removing operation, before regulating pH, add the organic acid salt of specified amount in the response type latex.Also can behind pH regulator, in response type latex, add organic acid salt.At this moment, condition is that the pH that will add the response type latex behind the organic acid salt maintains in 7 to 8 the scope.
On the other hand, when containing the organic acid salt derived from organic peracid in the response type latex after removing operation, add hydrogenation catalyst after, directly with the pH regulator to 7 of the response type latex scope to 8.As hydrogenation catalyst, can use homogeneous catalyst and heterogeneous catalyst.As hydrogenation catalyst, specifically can enumerate the metal catalysts such as nickel, ruthenium, platinum, palladium, rhodium.
Behind the pH that has regulated response type latex, under air atmosphere, under the atmosphere of inert gases such as argon or nitrogen or under the hydrogen atmosphere, in response type latex, supply with hydrogen.In this case, can directly supply with the hydrogen such as high pressure hydrogen, perhaps, also can add the composition (hydrogen donor) that can generate hydrogen thereby the hydrogen that supply generates in reaction system.Then, in the presence of hydrogenation catalyst, make hydrogen under assigned temperature, contact the regular hour with epoxidezed rubber shaped polymer in the response type latex.
As a result, hydrogen atom is added on the unsaturated double-bond that remains on the epoxidezed rubber shaped polymer main chain, and unsaturated double-bond is reduced thus.Simultaneously, the epoxy ring-opening on the epoxidezed rubber shaped polymer main chain, hydrogen atom is added on the Sauerstoffatom simultaneously, thereby forms hydroxyl.Thus, thereby being reduced unsaturated double-bond, the unsaturated double-bond on the main chain reduces, simultaneously, a part of initial ring oxidation and the open loop of unsaturated double-bond, thus modified natural rubber with hydroxyl (below, simply be recited as modified natural rubber) generated.
In the reductive ring open reaction, the hydrogen adding rate of resultant modified natural rubber is preferably more than 80%.The hydrogen adding rate of modified natural rubber can be regulated by the treatment temp and the treatment time that change in the reductive ring open reaction.Treatment temp in the reductive ring open reaction is preferably set to 0 to 100 ℃ scope, more preferably is set as 40 to 80 ℃ scope.During 0 ℃ for the treatment of temp less than, be difficult to fully react.When treatment temp surpassed 100 ℃, the molecular rupture of epoxidezed rubber shaped polymer may cause lower molecular weight.
The hydrogen adding rate of modified natural rubber can be calculated by following formula." double key number of rubbery polymer " in the formula (numerical value before the epoxidation) and " residues of two keys of modified natural rubber " can be obtained by the measurement result of (for example) 1H-NMR.
[mathematical expression 2]
＜recovery process 〉
The operation of recovery process for the modified natural rubber in the response type latex is reclaimed.Rubber constituent is reclaimed in employing from the latex that is dispersed with rubber constituent known method reclaims modified natural rubber.For example, by in response type latex, adding methyl alcohol, make the condensing and precipitation of modified natural rubber in the response type latex.Then, by reclaiming its throw out, can isolate modified natural rubber.At this moment, preferably before adding methyl alcohol, remove the hydrogenation catalyst in the response type latex.As the method for removing hydrogenation catalyst, can enumerate (such as) add the complexing agent such as dimethylglyoxime in the response type latex, make the hydrogenation catalyst precipitation and the method that is removed.
Next for the action effect of the present embodiment, be described below.
(1) removing in the operation behind epoxidation process is dispersed with under the latex state of epoxidezed rubber shaped polymer in maintenance, removes the material derived from organic peracid from response type latex.Then, the response type latex that the material derived from organic peracid has been removed is processed in ensuing reductive ring open operation.Therefore, do not separate after not needing as traditionally from response type latex will the epoxidezed rubber shaped polymer to solidify and make with extra care, and to make the epoxidezed rubber shaped polymer redispersion after the curing be the operation of latex shape.Thereby can be omitted in separating treatment that carry out, the epoxidezed rubber shaped polymer and redispersion processing between epoxidation process and the reductive ring open operation.Therefore can simplify the manufacturing process behind the epoxidation process.In addition, can be not to separating from the rubber constituent in the response type latex (rubbery polymer or epoxidezed rubber shaped polymer) and make with extra care, and under the state that keeps latex, carry out continuously epoxidation process and reductive ring open operation.Working efficiency when having improved thus manufacturing and the productive rate of the natural modified rubber of final product.
(2) in removing operation, the part that is dissolved with derived from the dispersion medium of the material of organic peracid in the response type latex is replaced with new dispersion medium.Thus, for the contained water-soluble impurity in raw material natural rubber latex Ruzhong, also can be in removing operation together be removed with material derived from organic peracid.
(3) in removing operation, the protein that exists in the response type latex with together be removed derived from the material of organic peracid.Therefore, there is no need newly to append lock out operation be used to making rubber constituent and protein separation.Thereby can be controlled to be bottom line with appending the workload increase that the deproteinated operation follows.
(4) under pH is 7 to 8 condition, and in the presence of organic acid salt, carry out the reductive ring open reaction.Can suppress thus the cyclisation of reductive ring open when reaction epoxidezed rubber shaped polymer etc.
(5) when the molecular weight of modified natural rubber reduced, the intensity of modified natural rubber also can reduce.In this, according to above-mentioned embodiment, because the treatment temp when reductive ring open reacted is set in 0 to 100 ℃ the scope, the lower molecular weight of the epoxidezed rubber shaped polymer in the time of therefore can suppressing the reductive ring open reaction and the modified natural rubber that obtained by the epoxidezed rubber shaped polymer.Thereby the strength decreased that also can suppress the modified natural rubber that the lower molecular weight owing to modified natural rubber causes.
The present embodiment also can as described belowly change.
The deproteinated that can omit when removing operation is processed.That is, removing outside the operation, for example, can before epoxidation process, carry out deproteinization and process.In addition, also can not carrying out deproteinated fully processes.
In the above-described embodiment, in epoxidation process, carry out the neutralizing treatment of response type latex, but carried out neutralizing treatment after also can or removing operation in removing operation.
The manufacture method of the modified natural rubber of above-mentioned embodiment can be applied to the method for modifying of natural rubber.
Embodiment
The below enumerates each embodiment and Comparative Examples so that above-mentioned embodiment is more specifically illustrated.
The preparation of＜response type latex 〉
As the raw material natural rubber latex, (rubber constituent concentration (rubbery polymer concentration) is 60.2 quality % to have used the singleHA latex of GOLDEN HOPE PLANTATION company system, the ammonia composition is 0.7 quality %, and the median size of rubber grain is about 1 μ m).Then, dilute above-mentioned raw materials latex with distilled water, add simultaneously anionic surfactant so lauryl sulfate (below be designated as SDS).Be that 10 quality %, SDS concentration are the response type latex of 1 quality % thereby make rubber constituent concentration (rubber polymer concentration).
＜epoxidation process and remove operation (comprise deproteinated process)
As the epoxidation process of natural rubber, generally process with peracetic acid or peroxyformic acid.In this test, consider from the angle of security, adopted peracetic acid to process.But, even when adopting peroxyformic acid to process, also can access the result identical with above-mentioned situation.Specifically be described below.
Speed with 1ml/ second is added drop-wise to the 10ml peracetic acid in the 100g response type latex.Then, vibration is 3 hours under 6 ℃ condition, makes the reaction of response type latex and peracetic acid.Then response type latex is carried out centrifuging treatment (15 ℃, 10000G, 30 minutes).Thus, response type latex is separated into the upper strata of emulsus and aqueous lower floor (lock out operation).Emulsus latex to the upper strata reclaims, and adds simultaneously the SDS aqueous solution of 1 quality % in the upper strata.Be the response type latex (redispersion operation) of 10 quality % thereby again make rubber constituent concentration (epoxidezed rubber shaped polymer concentration).
Next, use 28% ammoniacal liquor, the response type latex of again preparing is neutralized.After the neutralizing treatment, with respect to 100 mass parts rubber constituents in the response type latex, add the urea of 0.1 mass parts.Then 25 ℃ of lower stirrings 2 hours, make the protein denaturation in the response type latex.Repeat lock out operation and the redispersion operation of predetermined number of times thereafter.In the 1st (adding up to the 2nd time) lock out operation and redispersion operation after neutralizing treatment and protein denaturation are processed, the protein after the sex change is with being removed as acetic acid and acetate derived from the material of peracetic acid.In adding up to the 2nd later redispersion operation, again prepare response type latex so that rubber constituent concentration (epoxidezed rubber shaped polymer concentration) is 30 quality %.
At this, use 1H-NMR to measure being present in acetic acid in the response type latex and the concentration of ammonium acetate.Particularly, add the internal standard substance (reference material) of known quantity to the response type latex that is used for 1H-NMR, then carry out the mensuration of 1H-NMR, with comparing based on the peak of internal standard substance and peak based on acetic acid and ammonium acetate in the gained NMR spectrum.Thereby can confirm: with respect to the epoxidezed rubber shaped polymer of 100 mass parts, in the response type latex is below 35 mass parts derived from the acetic acid of peracetic acid and the total content of ammonium acetate.
＜reductive ring open operation 〉
At first, the Palladous chloride with specified amount is dissolved in the hydrochloric acid preparation hydrogenation catalyst.The rubber constituent concentration that next, will obtain in removing operation (epoxidezed rubber shaped polymer concentration) is that 30 quality %, SDS concentration are that the response type latex of 1 quality % is with the dilution of the SDS aqueous solution of 1 quality %.Thereby the rubber constituent concentration in the response type latex (epoxidezed rubber shaped polymer concentration) is adjusted to prescribed concentration.After dripping above-mentioned hydrogenation catalyst in the 100ml response type latex, use aqueous sodium hydroxide solution with the pH regulator of the response type latex pH value as appointment.Thereafter, under 70 ℃ condition, Yi Bian fully stir, Yi Bian in response type latex, make hydrogen carry out bubbling 9 hours with 100ml/ minute flow.
Next, the temperature of response type latex is cooled to 40 ℃, adds the 4ml hydrogen peroxide and also stirred 1 hour.In addition, add 1g dimethylglyoxime and stirring 48 hours.Then, under 40 ℃, response type latex was left standstill 24 hours so that the hydrogenation catalyst precipitation.By decant isolate supernatant liquor thereafter.Add methyl alcohol in the supernatant liquor after separate, make rubber constituent condensing.Then by reclaiming throw out, obtain modified natural rubber.
Table 1 and table 2 illustrate respectively the manufacture method of embodiment and Comparative Examples and the modified natural rubber that makes by these manufacture method.In each embodiment, " multiplicity of lock out operation and redispersion operation ", " the rubber constituent concentration in the reductive ring open operation in the response type latex (epoxidezed rubber shaped polymer concentration) " and " amount of employed catalyzer in the reductive ring open operation ", " pH during the reductive ring open operation " have been changed respectively.
In addition, Comparative Examples 1 is for having omitted the example of removing operation.In Comparative Examples 1, will pass through the response type latex of neutralizing treatment and directly in ensuing reductive ring open operation, process.The example of pH outside 7 to 8 scope when Comparative Examples 2 and 3 is reacted for reductive ring open.Comparative Examples 4 is not for carrying out the example of reductive ring open reaction in the presence of organic acid salt.In Comparative Examples 4, in order in manufacturing processed, not generate organic acid salt, and the part of manufacture method is changed.Particularly, prepared in epoxidation process and not carried out the operation of lock out operation and redispersion through neutralizing treatment and treated response type latex in the reductive ring open operation.Operate, carry out dilution process simultaneously by repeated isolation operation and redispersion, the pH that makes response type latex is 7.Then, in the reductive ring open operation, be that 7 response type latex carries out 9 hours heating under 70 ℃ to pH only, and do not carry out hydrogenation catalyst interpolation, utilize the pH regulator of aqueous sodium hydroxide solution and the bubbling of hydrogen.
[table 1]
※ 1: the operation before the neutralization is also counted as 1 time.
※ 2: acetic acid in the response type latex after the operation and the concentration of salt thereof are removed in expression.
※ 3: the rubber constituent concentration (epoxidezed rubber shaped polymer concentration) in the response type latex in the expression reductive ring open operation.
[table 2]
※ 1: the operation before the neutralization is also counted as 1 time.
※ 2: acetic acid in the response type latex after the operation and the concentration of salt thereof are removed in expression.
※ 3: the rubber constituent concentration (epoxidezed rubber shaped polymer concentration) in the response type latex in the expression reductive ring open operation.
As shown in table 1, after epoxidation process, to have carried out removing among each embodiment of operation, the concentration of acetic acid and salt thereof (ammonium acetate) is below the 1 quality %.The result can confirm thus, is adopting in the situation of removing operation of the present invention, also effectively separating ring oxygenated rubber shaped polymer and acetic acid and salt thereof.And in each embodiment, cyclisation does not occur in the epoxidezed rubber shaped polymer in ensuing reductive ring open operation, obtains modified natural rubber.
As shown in table 2, behind epoxidation process, and then directly carry out in the Comparative Examples 1 of reductive ring open operation, when reductive ring open reacted, the epoxidezed rubber shaped polymer in the response type latex was condensing and become the state that granular substance swims.The result can not obtain the purpose modified natural rubber.This is because the side reaction that a large amount of acetic acid that exist and salt thereof cause causes the epoxidezed rubber shaped polymer generation cyclisation in the response type latex.
PH when Comparative Examples 2 and 3 is reacted for reductive ring open is respectively 9 and 6 example.Comparative Examples 4 is for carrying out the example of reductive ring open reaction in the situation that does not have organic acid salt.Also the same with Comparative Examples 1 in these situations, the epoxidezed rubber shaped polymer generation cyclisation in the response type latex can not obtain the purpose modified natural rubber.The result of Comparative Examples 1 to 3 shows that the cyclisation of the epoxidezed rubber shaped polymer when reacting in order to suppress reductive ring open need to make pH in 7 to 8 scope, and carries out the reductive ring open reaction in the presence of organic acid salt.
The analysis of＜modified natural rubber 〉
The hydrogen adding rate of the resulting modified natural rubber of manufacture method by each embodiment can be calculated based on the measurement result of using 1H-NMR.In addition, the contained extra high composition of molecular weight in the resulting modified natural rubber (below be designated as high molecular weight components) is measured by following method.Adding the modified natural rubber of cutting in small, broken bitsly in the toluene, to make its concentration be 0.1 quality %, and soak a week.Thereafter, by this toluene solution being carried out centrifuging treatment (15 ℃, 10000G, 30 minutes), is separated into the colloidal sol composition that dissolves in toluene and being insoluble to the gel component of toluene.The gel component that is insoluble to toluene is reclaimed as high molecular weight components, and with regenerant 50 ℃ of lower dry weeks.Weight to dried above-mentioned high molecular weight components is measured, and calculates simultaneously the ratio of high molecular weight components contained in the modified natural rubber according to the ratio of itself and feeding quantity.Ratio by the hydrogen adding rate of the resulting modified natural rubber of manufacture method of each embodiment and high molecular weight components is as shown in table 3.
Reference example 1 shown in the table 3 is for adopting traditional method to make the example of modified natural rubber.About reference example 1, it is different from the operation of each embodiment with the reductive ring open operation particularly to remove operation.In reference example 1, after the neutralizing treatment in epoxidation process, the epoxidezed rubber shaped polymer in the latex is solidified, and from dispersion medium, separate.Then, the epoxidezed rubber shaped polymer that separation obtains is dry, left standstill again 1 month, remove acetic acid and acetate.In addition, in the reductive ring open operation, dried epoxidezed rubber shaped polymer is dissolved in the p-Xylol, and in p-Xylol solution, adds p-toluene sulfonyl hydrazide.Then, 145 ℃ of lower backflows 6 hours, carry out the reductive ring open reaction.
[table 3]
As shown in table 3, in being 30 to 90% scope, the hydrogen adding rate added hydrogen by the resulting modified natural rubber of the manufacture method of each embodiment.That is, obtained the purpose modified natural rubber.In addition, use 1H-NMR that the ratio of the epoxy group(ing) in the modified natural rubber is measured.As a result, the quantity of epoxy group(ing) is reduced to the degree that can't measure.Infer that accordingly the epoxy group(ing) that imports is all open loops and form hydroxyl in the reductive ring open operation almost in epoxidation process.
In addition, contain high molecular weight components by the resulting modified natural rubber of the manufacture method of each embodiment with the ratio more than 35%.In contrast, do not contain above-mentioned high molecular weight components by the resulting modified natural rubber of the manufacture method of reference example 1.It is believed that the difference of the content of the high molecular weight components between each embodiment and the reference example is because the difference of the treatment temp in reductive ring open when reaction causes.
That is, owing to when reductive ring open reacts, the epoxidezed rubber shaped polymer in the response type latex and modified natural rubber are exposed to the open air under hot conditions, molecular rupture, thus lower molecular weight has occured.In the manufacture method of reference example 1, under 145 ℃ of such comparatively high tempss, carry out the reductive ring open reaction.It is believed that therefore the epoxidezed rubber shaped polymer when having promoted the reductive ring open reaction owing to such hot conditions and the lower molecular weight of modified natural rubber do not have high molecular weight components residual in the modified natural rubber that finally obtains.In contrast, in the manufacture method of each embodiment, under 70 ℃ of lower like this temperature, carry out the reductive ring open reaction.Therefore it is believed that owing to the lower molecular weightization of epoxidezed rubber shaped polymer and modified natural rubber in the reductive ring open reaction is suppressed, therefore in the modified natural rubber that finally obtains, high molecular weight components can residually be arranged.
As shown in table 3, contain a high proportion of high molecular weight components by the resulting modified natural rubber of the manufacture method of each embodiment.Therefore, the intensity of resulting modified natural rubber is high.In fact, measured the tensile strength (Tb) of passing through the resulting modified natural rubber of manufacture method of embodiment 5 and reference example 1.As a result, the measured value of the tensile strength of the modified natural rubber in embodiment 5 and the reference example 1 is respectively 3.99MPa and 0.97MPa.This shows, according to the manufacture method of each embodiment, can obtain the modified natural rubber high with the manufacture method phase specific tenacity of reference example.The tensile strength of modified natural rubber (Tb) is to measure like this: to the hexanodioic acid hydrazides by interpolation 4phr in the prepared modified natural rubber of manufacture method of embodiment 5 and reference example 1, under 180 ℃, 11MPa, carry out hot pressing in 20 minutes, gains as sample, are measured according to the standard of ISO 37 (JIS K6251).
Claims (5)
1. the manufacture method of a modified natural rubber is characterized in that, the method has following operation:
Epoxidation process, wherein, in the latex that the water that is scattered in by the rubbery polymer derived from plant that main chain is had a plurality of unsaturated double-bonds as dispersion medium forms, make the reaction of organic peracid and described rubbery polymer, thereby make a part of unsaturated double-bond initial ring oxidation of described rubbery polymer, obtain thus the epoxidezed rubber shaped polymer;
Remove operation, wherein, from latex, remove in described epoxidation process the material derived from organic peracid that is generated by described organic peracid, the content derived from the material of organic peracid is reduced to below 35 mass parts with respect to the described epoxidezed rubber shaped polymer of 100 mass parts; And
The reductive ring open operation, wherein, be under 7 to 8 the condition at pH, and in the presence of organic acid salt, make part or all reduction of unsaturated double-bond residual in the described epoxidezed rubber shaped polymer in the latex, make simultaneously part or all generation open loop of the epoxy group(ing) of described epoxidezed rubber shaped polymer.
2. the manufacture method of modified natural rubber according to claim 1 is characterized in that, removes in the operation described, and the part of the dispersion medium of the described material derived from organic peracid of being dissolved with in the latex is replaced with new dispersion medium.
3. according to claim 1 or the manufacture method of modified natural rubber claimed in claim 2, it is characterized in that, remove in the operation described, by the latex behind the described epoxidation process is carried out centrifuging treatment, the upper strata that described latex is separated into mainly be dispersed with described epoxidezed rubber shaped polymer and mainly be dissolved with the lower floor of described material derived from organic peracid, and, when removing described lower floor, new dispersion medium is added on described upper strata.
4. the manufacture method of the described modified natural rubber of any one to the claim 3 according to claim 1 is characterized in that, removes in the operation described, when removing described material derived from organic peracid, removes the glue protein of milk.
5. the manufacture method of the described modified natural rubber of any one to the claim 3 according to claim 1, it is characterized in that, in described reductive ring open operation, hydrogen atom is added on the unsaturated double-bond that residues in the described epoxidezed rubber shaped polymer, make simultaneously the epoxy group(ing) generation open loop of described epoxidezed rubber shaped polymer, thereby form hydroxyl.
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| PCT/JP2011/054944 WO2011108660A1 (en) | 2010-03-05 | 2011-03-03 | Method for producing modified natural rubber |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2004176013A (en) * | 2002-11-29 | 2004-06-24 | Nagaoka University Of Technology | Liquid epoxidized natural rubber and its manufacturing method |
| JP2008308601A (en) * | 2007-06-15 | 2008-12-25 | Sumitomo Rubber Ind Ltd | Rubber composition for tire and tire having tire member using the composition |
| JP2009173727A (en) * | 2008-01-23 | 2009-08-06 | Toyota Motor Corp | Modified rubber and method for producing it |
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| CA1116344A (en) * | 1976-06-02 | 1982-01-12 | William J. Schultz | Polymers containing 2,5-oxolanylene segments |
| JP3294903B2 (en) * | 1993-05-24 | 2002-06-24 | 花王株式会社 | Modified natural rubber and method for producing the same |
| JP2010084077A (en) * | 2008-10-01 | 2010-04-15 | Sumitomo Rubber Ind Ltd | Rubber composition for tire and tire |
| JP5414037B2 (en) * | 2009-04-16 | 2014-02-12 | 豊田合成株式会社 | Modified natural rubber and method for producing the same |
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| JP2004176013A (en) * | 2002-11-29 | 2004-06-24 | Nagaoka University Of Technology | Liquid epoxidized natural rubber and its manufacturing method |
| JP2008308601A (en) * | 2007-06-15 | 2008-12-25 | Sumitomo Rubber Ind Ltd | Rubber composition for tire and tire having tire member using the composition |
| JP2009173727A (en) * | 2008-01-23 | 2009-08-06 | Toyota Motor Corp | Modified rubber and method for producing it |
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