WO2012077633A1 - Caoutchouc naturel solide et procédé pour le produire - Google Patents

Caoutchouc naturel solide et procédé pour le produire Download PDF

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Publication number
WO2012077633A1
WO2012077633A1 PCT/JP2011/078061 JP2011078061W WO2012077633A1 WO 2012077633 A1 WO2012077633 A1 WO 2012077633A1 JP 2011078061 W JP2011078061 W JP 2011078061W WO 2012077633 A1 WO2012077633 A1 WO 2012077633A1
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Prior art keywords
natural rubber
radical generator
solid natural
rubber
solid
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PCT/JP2011/078061
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English (en)
Japanese (ja)
Inventor
昭雄 間瀬
脇坂　治
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東海ゴム工業株式会社
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Priority to CN201180058857.3A priority Critical patent/CN103249744B/zh
Publication of WO2012077633A1 publication Critical patent/WO2012077633A1/fr

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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
    • 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
    • C08C19/08—Depolymerisation

Definitions

  • the present invention relates to a solid natural rubber which does not require mastication and whose viscosity hardly changes with time, and a method for producing the same.
  • Natural rubber has excellent properties such as high tensile strength and low heat generation due to vibration. For this reason, it has been conventionally used as a raw material for various rubber products such as tires, anti-vibration rubber, belts and rubber gloves. Solid natural rubber distributed as a raw material for producing rubber products is roughly classified into visual rating rubber (VGR) and technical rating rubber (TSR).
  • VGR visual rating rubber
  • TSR technical rating rubber
  • a representative example of VGR is a smoke sheet (RSS) based on a rating based on “International Quality Packaging Standard for Natural Rubber Grades (commonly called Green Book)”.
  • RSS is manufactured as follows. First, after adding acid such as formic acid or acetic acid to the field latex and coagulating it, it is placed on a work table and stretched with a stick to adjust the thickness.
  • TSR smokeless sheet
  • the molecular weight is large and the viscosity is high. Therefore, when solid natural rubber such as RSS is used as a raw material for producing rubber products, it is necessary to perform mastication in advance in order to reduce viscosity and improve processability.
  • JP 2003-320524 A JP 2003-313366 A JP 2009-275165 A JP-A-9-136903
  • Patent Document 4 discloses a method for producing a liquid depolymerized natural rubber, in which a carbonyl compound is added to natural rubber latex and air-oxidized in the presence of a radical generator.
  • the carbonyl compound plays a role of binding to the molecular end of the depolymerized natural rubber and suppressing repolymerization (paragraph [0013] of Patent Document 4). That is, according to the method disclosed in Patent Document 4, a carbonyl compound is added in order to suppress recombination of the cleaved molecular chain by the generated aldehyde group.
  • the present invention has been made in view of such circumstances, a solid natural rubber having a desired viscosity without being masticated and having a viscosity that is difficult to increase during storage, and a method for producing the same.
  • the issue is to provide.
  • the solid natural rubber of the present invention has a low molecular weight by cutting a molecular chain and is characterized by not containing an aldehyde group in the molecular chain.
  • Conventional solid natural rubber has a low molecular weight and is adjusted to a desired viscosity by cutting the molecular chain of the rubber by mastication.
  • an aldehyde group or the like is generated at the end of the molecular chain during mastication.
  • the solid natural rubber of the present invention has a low molecular weight by cutting the molecular chain and is adjusted to a desired viscosity, but does not contain an aldehyde group in the molecular chain. Therefore, there is little risk that the viscosity will increase due to recombination of aldehyde groups during storage. Moreover, since it has already been adjusted to a desired viscosity, it is not necessary to perform mastication. For this reason, the solid natural rubber of the present invention can be used as it is as a raw material for producing rubber products. Therefore, according to the solid natural rubber of the present invention, the problem of viscosity variation that has conventionally occurred in rubber after mastication is solved.
  • not containing an aldehyde group means that a shift derived from an aldehyde group is detected in 1 H-NMR measurement using an NMR (nuclear magnetic resonance) apparatus “INOVA-400” manufactured by Varian. Means not.
  • the manufacturing method of the solid natural rubber of this invention adds the radical generator to natural rubber latex, advances the radical generator addition process which advances the oxidation reaction which cut
  • the viscosity of the natural rubber after solidification can be adjusted by cutting the molecular chain of the rubber in the latex state.
  • the molecular chain cleavage and oxidation reaction are performed at room temperature for several minutes to several hours. For this reason, the viscosity of the solid natural rubber can be adjusted easily and stably without providing any heating equipment.
  • the entire latex can be made to react more uniformly than when kneading (dry kneading). For this reason, the viscosity is less likely to vary from lot to lot.
  • the obtained solid natural rubber is adjusted to a desired viscosity. For this reason, it can be used as it is as a raw material for producing rubber products without mastication. That is, according to the production method of the present invention, it is possible to produce solid natural rubber that does not require mastication from natural rubber latex. Since the mastication step can be omitted, the number of steps can be reduced. As a result, it is possible to reduce the manufacturing time and cost of the rubber product. Furthermore, the molecular chain of the solid natural rubber obtained does not contain aldehyde groups. Therefore, the viscosity increase in the solid natural rubber during storage can be suppressed.
  • solid natural rubber and the method for producing the same according to the present invention will be described.
  • the solid natural rubber and the method for producing the same according to the present invention are not limited to the following embodiments, and various modifications and improvements that can be made by those skilled in the art without departing from the gist of the present invention. It can be implemented in the form.
  • the solid natural rubber of the present invention has a low molecular weight by cutting a molecular chain, and does not contain an aldehyde group in the molecular chain.
  • a molecular weight should just be small compared with conventional unpaste solid natural rubbers, such as RSS.
  • the viscosity of the solid natural rubber decreases.
  • the weight average molecular weight by gel permeation chromatography (GPC) is preferably 1 ⁇ 10 6 or less.
  • the Mooney viscosity [ML (1 + 3) 121 ° C.] of the solid natural rubber is preferably 80 or less.
  • the Mooney viscosity [ML (1 + 3) 121 ° C.] is more preferably 30 or more and 70 or less.
  • the Mooney viscosity employs a value measured according to JIS K6300-1 (2001).
  • the presence or absence of an aldehyde group may be determined by 1 H-NMR measurement using an NMR apparatus “INOVA-400” manufactured by Varian, as described above.
  • the solid natural rubber of the present invention can be obtained by solidifying a natural rubber latex to which a radical generator is added. Hereinafter, the manufacturing method of the solid natural rubber of this invention is demonstrated.
  • the method for producing a solid natural rubber according to the present invention includes a radical generator addition step and a solidification step. Hereinafter, each step will be described.
  • Radical generator addition process This process is a process in which a radical generator is added to natural rubber latex and an oxidation reaction for cutting the molecular chain of the rubber proceeds.
  • a field latex collected by tapping or a latex (high ammonia latex) treated with ammonia added thereto may be used.
  • the rubber content (dry rubber mass, hereinafter the same) concentration of natural rubber latex is not particularly limited. If the rubber concentration is too low, the amount of solid natural rubber obtained is small, which is not economical. On the other hand, if the rubber concentration is too high, the rubber component in the latex becomes unstable and the rubber particles aggregate during the oxidation reaction, making it difficult to make the oxidation reaction proceed uniformly.
  • the rubber concentration is desirably 10% by mass or more and 60% by mass or less.
  • peroxide radical generators include potassium persulfate (KPS), ammonium persulfate (APS), benzoyl peroxide (BPO), hydrogen peroxide, cumene hydroperoxide, tert-butyl hydroperoxide (TBHPO), di- -Tert-butyl peroxide, 2,2-azobisisobutyronitrile and the like.
  • KPS potassium persulfate
  • APS ammonium persulfate
  • BPO benzoyl peroxide
  • hydrogen peroxide cumene hydroperoxide
  • THPO tert-butyl hydroperoxide
  • di- -Tert-butyl peroxide 2,2-azobisisobutyronitrile and the like.
  • Examples of the reducing agent combined with the peroxide as the redox radical generator include tetraethylenepentamine (TEPA), mercaptans, acidic sodium sulfite, reducing metal ions, ascorbic acid and the like.
  • suitable combinations include TBHPO and TEPA, hydrogen peroxide and Fe 2+ salt, KPS and sodium acid sulfite, and the like.
  • Examples of the azo radical generator include azobisisobutyronitrile, methyl azobisisobutyrate, azobiscyclohexanecarbonitrile, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid, and the like.
  • KPS potassium persulfate
  • APS ammonium persulfate
  • BPO benzoyl peroxide
  • the addition amount of the radical generator may be appropriately determined according to the kind of the radical generator so that the obtained solid natural rubber can be adjusted to a desired viscosity.
  • the viscosity of the solid natural rubber can be adjusted by increasing or decreasing the amount of radical generator added. For example, if the amount of radical generator added is too small, it is difficult to adjust the viscosity to a low level because the molecular chain scission and the oxidation reaction do not proceed easily. Conversely, the addition of excess radical generator is not economical.
  • the addition amount of the radical generator is desirably 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the rubber content in the natural rubber latex.
  • the molecular chain scission and oxidation reaction may be performed while stirring natural rubber latex to which a radical generator is added at room temperature.
  • the reaction time is adjusted depending on the required viscosity, but may be about several minutes to several hours.
  • This step is a step of obtaining natural rubber containing no aldehyde group in the molecular chain by drying and solidifying the natural rubber latex after the oxidation reaction.
  • the method for drying the natural rubber latex is not particularly limited. What is necessary is just to perform by spray drying, a drum dryer, a conveyor type dryer, etc.
  • the drying temperature is preferably about 50 to 200 ° C. from the viewpoint of efficiently removing moisture in consideration of deterioration of rubber due to heat. Moreover, it is desirable to finish the drying process within a few minutes.
  • the preferable Mooney viscosity of the obtained solid natural rubber and the method for determining the presence or absence of aldehyde groups are as described above.
  • Example 1 As natural rubber latex, high ammonia latex (rubber content concentration 60.2 mass%, ammonia content concentration 0.7 mass%) manufactured by Golden Hope (Malaysia) was used. First, the high ammonia latex was diluted so that the rubber concentration was 30% by mass. Next, a predetermined amount of potassium persulfate (KPS) as a radical generator was added to 100 g of diluted latex rubber, and the mixture was stirred at room temperature for 10 minutes. And the latex after reaction was dried in 50 degreeC oven, and solidified. Thus, the solid natural rubber of Example 1 was obtained.
  • KPS potassium persulfate
  • Example 2 A solid natural rubber of Example 2 was obtained in the same manner as in Example 1 except that the radical generator was changed to ammonium persulfate (APS).
  • APS ammonium persulfate
  • Example 3 A solid natural rubber of Example 3 was obtained in the same manner as in Example 1 except that the radical generator was changed to benzoyl peroxide (BPO).
  • BPO benzoyl peroxide
  • Mooney viscosity measurement> About the obtained solid natural rubber, Mooney viscosity was measured.
  • the Mooney viscosity was measured using a rotor-type Mooney viscometer manufactured by Toyo Seiki Seisakusho. Then, the rotational speed of the L-shaped rotor was 2 rpm, the measurement temperature was 121 ° C., preheating was performed for 1 minute, and then the Mooney viscosity after 3 minutes was measured.
  • FIG. 1 shows the Mooney viscosity value of solid natural rubber with respect to the amount of radical generator added.
  • the Mooney viscosity of solid natural rubber was reduced by adding a radical generator to natural rubber latex. Further, as shown in the graphs of Example 1 (KPS) and Example 2 (APS), the Mooney viscosity of the solid natural rubber decreased as the amount of radical generator added increased. As mentioned above, according to the manufacturing method of this invention, it was confirmed that the solid natural rubber which has desired viscosity can be manufactured.
  • a solid natural rubber having a desired viscosity can be easily obtained. Therefore, the mastication process can be omitted. Thereby, the problem of the viscosity dispersion

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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)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Processes Of Treating Macromolecular Substances (AREA)

Abstract

L'invention concerne un procédé de production d'un caoutchouc naturel solide qui comprend une étape d'addition d'un agent produisant des radicaux qui consiste en l'addition d'un agent produisant des radicaux à un latex de caoutchouc naturel et la progression d'une réaction d'oxydation consistant à couper les chaînes moléculaires du caoutchouc ; et une étape de solidification qui consiste en le séchage et la solidification du latex de caoutchouc naturel après la réaction d'oxydation pour ainsi obtenir un caoutchouc naturel qui ne contient aucun groupe aldéhyde dans ses chaînes moléculaires. Le caoutchouc naturel solide obtenu a un poids moléculaire réduit car les chaînes moléculaires ont été coupées et ne contient aucun groupe aldéhyde dans les chaînes moléculaires. Ainsi, le caoutchouc naturel solide acquière une viscosité désirée même sans mastication, et sa viscosité est moins susceptible d'augmenter pendant le stockage.
PCT/JP2011/078061 2010-12-06 2011-12-05 Caoutchouc naturel solide et procédé pour le produire WO2012077633A1 (fr)

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Application Number Priority Date Filing Date Title
CN201180058857.3A CN103249744B (zh) 2010-12-06 2011-12-05 固体天然橡胶及其制造方法

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JP2010271681A JP5745831B2 (ja) 2010-12-06 2010-12-06 固形天然ゴムおよびその製造方法
JP2010-271681 2010-12-06

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014136458A1 (fr) * 2013-03-07 2014-09-12 東洋ゴム工業株式会社 Procédé de production d'un polymère modifié, et composition de caoutchouc
JP2014172974A (ja) * 2013-03-07 2014-09-22 Toyo Tire & Rubber Co Ltd 変性ポリマーの製造方法及びジエン系ポリマー

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5900526B2 (ja) * 2014-03-27 2016-04-06 横浜ゴム株式会社 ゴム組成物及びこれを用いる空気入りタイヤ
WO2019102109A1 (fr) * 2017-11-23 2019-05-31 Compagnie Generale Des Etablissements Michelin Caoutchouc naturel
CN108424530B (zh) * 2018-03-14 2021-05-07 中国化工株洲橡胶研究设计院有限公司 一种杜仲胶乳的制备方法

Citations (6)

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JPS62207301A (ja) * 1986-03-01 1987-09-11 ヒユ−ルス・アクチエンゲゼルシヤフト ラテツクス状の天然ゴムの分子量減成法
JPH09136903A (ja) * 1995-11-10 1997-05-27 Kao Corp 解重合天然ゴムの製造方法
JP2001261707A (ja) * 2000-03-23 2001-09-26 Okayama Prefecture 天然ゴムの解重合方法
JP2007277450A (ja) * 2006-04-10 2007-10-25 Mitsubishi Gas Chem Co Inc 低分子量天然ゴム
JP2007277310A (ja) * 2006-04-03 2007-10-25 Bridgestone Corp ゴム組成物及びそれを用いた空気入りタイヤ
JP2009013278A (ja) * 2007-07-04 2009-01-22 Sumitomo Rubber Ind Ltd 解重合天然ゴムの製造方法

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TWI296642B (fr) * 2000-01-24 2008-05-11 Nitto Denko Corp

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62207301A (ja) * 1986-03-01 1987-09-11 ヒユ−ルス・アクチエンゲゼルシヤフト ラテツクス状の天然ゴムの分子量減成法
JPH09136903A (ja) * 1995-11-10 1997-05-27 Kao Corp 解重合天然ゴムの製造方法
JP2001261707A (ja) * 2000-03-23 2001-09-26 Okayama Prefecture 天然ゴムの解重合方法
JP2007277310A (ja) * 2006-04-03 2007-10-25 Bridgestone Corp ゴム組成物及びそれを用いた空気入りタイヤ
JP2007277450A (ja) * 2006-04-10 2007-10-25 Mitsubishi Gas Chem Co Inc 低分子量天然ゴム
JP2009013278A (ja) * 2007-07-04 2009-01-22 Sumitomo Rubber Ind Ltd 解重合天然ゴムの製造方法

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014136458A1 (fr) * 2013-03-07 2014-09-12 東洋ゴム工業株式会社 Procédé de production d'un polymère modifié, et composition de caoutchouc
JP2014172974A (ja) * 2013-03-07 2014-09-22 Toyo Tire & Rubber Co Ltd 変性ポリマーの製造方法及びジエン系ポリマー
CN105189565A (zh) * 2013-03-07 2015-12-23 东洋橡胶工业株式会社 改性聚合物的制造方法及橡胶组合物
US9969850B2 (en) 2013-03-07 2018-05-15 Toyo Tire & Rubber Co., Ltd. Method for producing modified polymer, and rubber composition

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MY163195A (en) 2017-08-15
JP5745831B2 (ja) 2015-07-08
CN103249744A (zh) 2013-08-14
CN103249744B (zh) 2015-06-10
JP2012121946A (ja) 2012-06-28

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