JP4251858B2 - Powdered rubber with an uneven surface, rubber composition and tire using the same - Google Patents
Powdered rubber with an uneven surface, rubber composition and tire using the same Download PDFInfo
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- JP4251858B2 JP4251858B2 JP2002344276A JP2002344276A JP4251858B2 JP 4251858 B2 JP4251858 B2 JP 4251858B2 JP 2002344276 A JP2002344276 A JP 2002344276A JP 2002344276 A JP2002344276 A JP 2002344276A JP 4251858 B2 JP4251858 B2 JP 4251858B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、高い破壊特性及び高い耐磨耗性を維持するゴム組成物を得るための粉ゴムとそれを配合したゴム組成物に関する。
【０００２】
【従来の技術】
廃タイヤは、一般のプラスチック製品と比較して回収率は高く、特にセメント工場を中心に燃料として再利用されている。しかしながら、近年、タイヤゴム片あるいはゴム粉末をそのまま使用する、いわゆるマテリアルリサイクル率の向上が求められており、廃タイヤ等の廃ゴムを再利用する方法として二軸押出機などで大きな剪断力を加える粉砕脱硫方法、微粒粉砕法や粉砕した加硫ゴムの様々な脱硫方法が検討されているが、エネルギーコストが高くなるという問題がある。
【０００３】
そこで、省エネルギー的な方法として、微生物による処理が検討されている。微生物処理は、低温での処理なので、エネルギー消費は最も少ない処理法といえる。微生物処理については特開平９―１９４６２４、特開平１１―６０７９３に硬質ゴムを効率よく分解処理する方法が提案されているが、いずれもゴム片を完全に分解することを念頭にした処理方法が示されているだけで、どのようにすればマテリアルリサイクルに有効な粉ゴムを得ることができるかについては何も述べられていない。
【０００４】
【発明が解決しようとする課題】
本発明は、廃ゴムから少ないエネルギーで、従来の粉ゴムを使用した場合に比べ、高い破壊特性及び高い耐磨耗性を維持するゴム組成物を得るための粉ゴムとそれを配合したゴム組成物を得ることを目的とする。
【０００５】
【課題を解決するための手段】
本発明者らは、上記の問題を解決するために鋭意検討した結果、廃ゴムを従来法で粉砕した特定サイズの粉末ゴムの表面に、更に凹凸を増やす表面処理を行うことで、該粉末ゴムを用いたゴム組成物は高い破壊物性が得られること、この凹凸を増やす方法としては限定されないが、特に微生物による分解手法が有効であることを見出し本発明を完成させるに至った。
【０００６】
すなわち、本発明は次の（１）〜（９）からなる。
（１） 表面に凹凸化処理を施した粉ゴム。
（２） 凹凸化処理が、微生物を用いてなされたことを特徴とする上記（１）に記載の粉ゴム。
（３） 微生物が、シュードノカルディアセアエ(Pseudonocardiaceae)に属する微生物であることを特徴とする上記（２）に記載の粉ゴム。
（４） シュードノカルディアセアエ(Pseudonocardiaceae)に属する微生物が、ＷＵ−ＹＳ０５株、受託番号ＦＥＲＭ Ｐ−１８６６０であることを特徴とする上記（３）に記載の粉ゴム。
（５） 凹凸化処理前粉ゴムの平均粒径が１ｍｍ以下であることを特徴とする上記（１）から（４）のいずれか１項に記載の粉ゴム。
（６） 凹凸化処理前粉ゴムの平均粒径が０．２ｍｍ以下であることを特徴とする上記（５）に記載の粉ゴム。
（７） 凹凸化処理が、処理前後の粉ゴムの重量変化率が０．０１％から４０％の範囲でなされたことを特徴とする上記（１）から（６）のいずれか１項に記載の粉ゴム。
（８） 上記（１）から（７）のいずれか１項に記載の粉ゴムを用いたゴム組成物。
（９） 上記（８）に記載のゴム組成物を用いたことを特徴とするタイヤ。
【０００７】
本発明で利用される粉ゴムの原料となる廃ゴムのゴム種は、特に限定されない。また、微生物処理に利用する微生物は、土壌などからスクリーニングして分離することができる。
【０００８】
【発明の実施の形態】
以下、本発明の実施の形態を具体的に説明する。
本発明で利用される粉ゴムの原料となる廃ゴムのゴム種は、特に限定されるものでなく、天然ゴム及び合成ゴムの中から選ばれる少なくとも一種を含むものであればよい。合成ゴムとしては、ジエン系ゴムが好ましく、例えば、シス−１，４−ポリイソプレン、スチレン・ブタジエン共重合体、低シス−１，４−ポリブタジエン、高シス−１，４−ポリブタジエン、エチレン−プロピレン−ジエン共重合体、クロロブレンゴム、ハロゲン化ブチルゴム、アクリロニトリル−ブタジエンゴム等を例示できる。
【０００９】
粉ゴムの原料となる加硫ゴムには、ゴム工業で通常使用されているシランカップリング剤、硫黄、加硫剤、加硫促進剤、加硫促進助剤、酸化防止剤、オゾン劣化防止剤、老化防止剤、プロセス油、亜鉛華（ＺｎＯ）、ステアリン酸、過酸化物等が配合されている。
【００１０】
本発明は、かかる加硫ゴムからなる廃タイヤ・チューブ等を従来の方法で粉砕して得られる粉ゴムに限らず、タイヤ製造時等に発生する未加硫スクラップ物、タイヤ等加硫時に発生するスピュー片などを粉砕した粉ゴムも使用できる。
【００１１】
本発明では、粉ゴムの表面に凹凸化処理をすることにより、粒径を実質的に変えずにその表面積を上げることができ、そのような粉ゴムを使用することで、高い破壊物性のゴム組成物が得られる。
【００１２】
本発明の表面凹凸化処理の方法は、特に限定されず、具体的には、微生物を用いる方法、酸化分解、オゾン処理、プラズマ処理などを挙げることができる。なかでも、微生物を用いる方法が有効である。
【００１３】
本発明で使用できる微生物は、特に限定はないが、細菌、放線菌、真菌、白色腐朽菌の類が好ましい。
細菌では、Xantomonas sp.、Pseudomonas citronellolis、Pseudomonas aeruginosaが天然ゴムを分解することが知られており、また放線菌として、Nocardia sp.、Nocardia asteroides、Nocardia blasiliensis、Gordona sp.、Gordona polyisoprenivorans、Micromonospora aurantiaca、Micromonospora fortuitum、Sreptomyces coelicolor、Actinomyces elastica、Actinomyces fluscus、Proactinomyces ruber、Actinomadura libanotica、Actinoplanes missouriensi、Actinoplanes italicus、Actinoplanes utahensis、Dactylosporangium thailandense、Micromonospora sp.、Streptomyces sp.、Streptomyces acrimycini、Streptomyces albogriseu、Streptomyces albadunctus、Streptomyces antibioticus、Streptomyces atroolivaceus、Streptomyces aureocirculatus、Streptomyces daghestanicus、Streptomyces flavoviridi、Streptomyces fradiae、Streptomyces griseus、Streptomyces griseobrunneus、Streptomyces griseoflavus、Streptomyces griseoflavus、Streptomyces griseoviridis、Streptomyces nitrosporeus、Streptomyces olivaceus、Streptomyces olivoviridis、Streptomyces tauricus、Amycolatopsis sp.のような多くの放線菌の類が天然ゴムを分解することが知られている。本発明者らは、中でもPseudonocardiaceae に属する微生物、とりわけＷＵ−ＹＳ０５株が、天然ゴムの分解能力が高いことを発見した。
ＷＵ−ＹＳ０５株は、独立行政法人産業技術総合研究所 特許生物寄託センターに、受託番号ＦＥＲＭ Ｐ−１８６６０（寄託日：平成１３年１２月２１日）として寄託されている。
【００１４】
また、真菌（かび）の類では、Aspergillus sp.、Stemphylium macrosporoideum、Paecilomysces lilacinus、Phoma eupyrena、Fusarium solani、Cladosporium cladosporioideが天然ゴムを分解することが知られ、最近では白色腐朽菌、中でもCeriporiosis subvermisporaが天然ゴム及びＳＢＲなどの合成ゴムを分解することが報告されている。
【００１５】
本発明では、これらの微生物を単独及び複数を組み合わせて使用することができる。これらの微生物は、基本的にはゴムを唯一の炭素源として生育できるもので、ゴムを炭素源として生育するような環境にすることにより、土壌などからスクリーニングし、単離することが可能である。たとえば、放線菌の場合の液体培地としては表１に示すものが例示される。
【００１６】
【表１】
この培地には炭素源はないため、例えば、これに天然ゴムシートを添加することにより、上記の天然ゴム分解菌を生育させることができ、それを微生物処理の種菌とすることができる。
【００１８】
本発明における粉ゴムの微生物処理の仕方として、特に限定はしないが、例えば、上記の培地の中に粉ゴムを添加し、種菌として得たPseudonocardiaceaeに属する微生物のような菌を植菌すると、ゴム分解微生物がその粉ゴムを唯一の炭素源として増殖を始め、粉ゴムの表面を分解し、粉ゴムの表面に凹凸をつけることとなる。
【００１９】
微生物の培養条件は、通常の好気性微生物の培養条件とすることができ、液体培地１０００ｍｌ〜１００ｍｌあたり、菌の量は１白金耳、粉ゴムは１ｇ〜５ｇ、培養温度は常温（２５℃〜３５℃）、培養時間は凹凸化処理の程度によるが５〜２０日間である。
また、粉ゴムは、その表面の凹凸化処理前の粒径が１ｍｍ以下であることが好ましく、より好ましくは、０．５ｍｍ以下、さらに好ましくは０．２ｍｍ、特に好ましくは０．１ｍｍ以下である。もっと大きな粒径であっても、表面を凹凸化することにより所望の効果は得られるが、予めある程度小さくしておくことにより、より効率的に表面積の大きい粉ゴムを得ることができる。
【００２０】
表面の凹凸化処理の程度は、特に制限はなく、目的、用途に併せて適宜選択される。凹凸化処理の程度は、粉ゴムの重量変化率で判定することができ、粉ゴムの重量変化率が０．１％から４０％の範囲であることが好ましい。
培養後、粉ゴムを濾過し、有機溶剤及び水で洗浄し、乾燥後ゴム組成物の原料とする。
【００２１】
本発明の表面処理した粉ゴムを配合することにより、従来の粉ゴムを用いた場合よりも破壊特性、耐磨耗性に優れるゴム組成物を得ることができ、このようなゴム組成物をタイヤトレッド、サイドウォール、カーカスプライやベルトプライのコーティングゴムに用いると、従来の粉ゴムを用いたタイヤに比べると耐久性を向上させることができる。また、本発明のタイヤに充填する気体としては空気に限らず、窒素などの不活性なガスも使用できる。
【００２２】
実施例
次に、実施例および比較例により本発明を説明するが、本発明は下記実施例に何ら限定されるものではない。
【００２３】
１．微生物のスクリーニング
表１に示す培地１００ｍｌ中に土壌約１０ｍｇとアセトン抽出した天然ゴムラテックス手袋を５ｃｍ角に切ったゴム片を入れ、３０℃で２週間振とう培養し、ゴム片の表面に付着した菌を表１に示す培地と同一組成の溶液に、寒天１．５重量％を加えた固体培地上で分離し、ＷＵ−ＹＳ０５株（Pseudonocardiaceaeの微生物）を得た。
【００２４】
２．表面凹凸化処理
シリコーン栓付きのガラス容器に準備した表１に示す組成の培地に市販の粉ゴム（米国Rouse社製：２００メッシュ）５ｇ／ｌを入れ、９０℃でオートクレーブ中で滅菌処理した後、ＷＵ−ＹＳ０５株を白金耳により、無菌的に植菌した。３０℃で１０日間５０〜７０ｒｐｍの条件で振とう培養した後、粉ゴムをろ紙でろ過した。ろ紙上の粉ゴムをアセトンで数回洗浄後、純水で洗浄し、４０℃で真空乾燥して、配合する粉ゴムの試料とした。
また、比較用として微生物株を全く植菌しないで同様の処理を行った。
処理前後での重量減少率（分解率）は植菌したものが、０．８％に対して未植菌のものは０．１％未満であり、微生物により粉ゴムが分解されていることが確認された。
【００２５】
３．表面観察
乾燥後の粉ゴム表面を、日本電子株式会社社製走査電子顕微鏡（ＳＥＭ）で観察したところ、植菌せずに処理した粉ゴムと比べてPseudonocardiaceaeＹＳ０５株を植菌して処理した粉ゴムは、表面が明らかに侵食されて凸凹が微細になっていることが確認された。
【００２６】
４．再生ゴムの評価
上記の植菌した場合と、植菌しない場合で得た粉ゴムを使用し、新材のゴム成分に得られた粉ゴムとゴム配合剤を加えて、８０ｍｌプラストミルを用いて混練りし、トレッド用およびサイドウォール用ゴム組成物を得た。これを１５０℃２０分間加圧し、加硫ゴムサンプルを得た。
この組成物につき、耐摩耗性、破壊特性、亀裂成長性を測定し、再生ゴム（表面処理ゴム）を評価した。
【００２７】
１）ゴム組成物の調製
トレッド用ゴム組成物は、新材のＳＢＲ７０重量部とＢＲ３０重量部のゴム成分に対して表２に示す配合割合で、サイドウォール用組成物は、新材の天然ゴム５０重量部とＢＲ５０重量部のゴム成分に対して表３に示す配合割合で配合剤及び粉ゴムを配合しゴム組成物を得た。
粉ゴムの使用量は、各実施例、比較例について表４及び表５に示す。
【００２８】
【表２】
【表３】
２）測定方法
上記の組成物につき、耐摩耗性、破壊特性、耐亀裂成長性を下記の方法で測定し、再生ゴムを評価した。
評価は各特性とも、トレッド用の場合、比較例１（粉ゴムを使用せず、新材ゴムのみ）の値を１００とし、サイドウォール用の場合は比較例６（粉ゴム不使用の例）の値を１００として指数で表示した。指数が大きい程特性が優れている。
得られた結果を、表４、５に示す。
【００３１】
破壊特性
ＪＩＳ Ｋ６３０１−１９９５により、破壊強度（ＴB）を測定し、コントロールを１００とした指数で表わした。数値が大きい程、破壊特性は良好である。
【００３２】
耐亀裂成長性
ＪＩＳ Ｋ６３０１−１９９５と同様に試験を行ない、亀裂の長さが１０ｍｍとなったときの屈曲回数を測定し、コントロールを１００として指数で表した。数値が大きい程、耐亀裂成長性は良好である。
【００３３】
耐摩耗性
ランボーン摩耗法により測定した。測定条件は、負荷荷重が４．５ｋｇ、砥石の表面速度が１００ｍ／秒、試験速度が１３０ｍ／秒、スリップ率が３０％、落砂量が２０ｇ／分、測定温度が室温であった。コントロールを１００として指数で表示した。数値が大きい程結果が良好である。
【００３４】
【表４】
【表５】
【発明の効果】
粉ゴムを入れない比較例１に対し、未処理粉ゴムあるいは未植菌で処理した粉ゴムを配合すると破壊物性、耐摩耗性、耐亀裂成長性が大きく低下することが判る。これに対してＷＵ−ＹＳ０５株を植菌して処理した粉ゴムを用いると物性が大きく改良されることが確認された。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber powder and a rubber composition blended with it to obtain a rubber composition that maintains high fracture characteristics and high wear resistance.
[0002]
[Prior art]
Waste tires have a higher recovery rate than ordinary plastic products, and are reused as fuel, especially in cement factories. However, in recent years, tire rubber pieces or rubber powders are used as they are, and so-called material recycling rate improvement has been demanded. As a method of reusing waste rubber such as waste tires, grinding with a large shear force applied by a twin screw extruder or the like Various desulfurization methods, such as a desulfurization method, a fine particle pulverization method, and a pulverized vulcanized rubber, have been studied.
[0003]
Therefore, treatment with microorganisms has been studied as an energy-saving method. Microbial treatment is a treatment at a low temperature, so it can be said to be the treatment method with the least energy consumption. Regarding microbial treatment, methods for efficiently decomposing hard rubber have been proposed in Japanese Patent Application Laid-Open Nos. 9-194624 and 11-60793, and all of them show treatment methods with the intention of completely decomposing rubber pieces. However, nothing is said about how to obtain powdered rubber effective for material recycling.
[0004]
[Problems to be solved by the invention]
The present invention is a powder rubber for obtaining a rubber composition that maintains high fracture characteristics and high wear resistance compared to the case of using conventional powder rubber with less energy from waste rubber, and a rubber composition containing the same. The purpose is to get things.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have performed a surface treatment for increasing irregularities on the surface of a powder rubber of a specific size obtained by pulverizing waste rubber by a conventional method. The rubber composition using the above has a high destructive physical property and is not limited as a method for increasing the unevenness. However, the present invention has been completed by finding that the decomposition method using microorganisms is particularly effective.
[0006]
That is, this invention consists of following (1)-(9).
(1) Powdered rubber with a roughened surface.
(2) The rubber powder as described in (1) above, wherein the roughening treatment is performed using microorganisms.
(3) The powder rubber according to (2) above, wherein the microorganism is a microorganism belonging to Pseudonocardiaceae.
(4) The rubber powder as described in (3) above, wherein the microorganism belonging to Pseudonocardiaceae is WU-YS05 strain, accession number FERM P-18660.
(5) The powder rubber according to any one of (1) to (4) above, wherein an average particle diameter of the powdered rubber before the roughening treatment is 1 mm or less.
(6) The powder rubber according to (5) above, wherein the average particle diameter of the powder rubber before the roughening treatment is 0.2 mm or less.
(7) The unevenness treatment is performed in a range of 0.01% to 40% in weight change rate of the rubber powder before and after the treatment, according to any one of (1) to (6) above Powder rubber.
(8) A rubber composition using the powder rubber according to any one of (1) to (7) above.
(9) A tire using the rubber composition according to (8).
[0007]
The rubber type of the waste rubber used as a raw material for the powder rubber used in the present invention is not particularly limited. In addition, microorganisms used for microbial treatment can be screened and separated from soil.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described.
The rubber type of the waste rubber used as a raw material for the powder rubber used in the present invention is not particularly limited, and may be any as long as it contains at least one selected from natural rubber and synthetic rubber. The synthetic rubber is preferably a diene rubber such as cis-1,4-polyisoprene, styrene-butadiene copolymer, low cis-1,4-polybutadiene, high cis-1,4-polybutadiene, or ethylene-propylene. -Diene copolymer, chlorobrene rubber, halogenated butyl rubber, acrylonitrile-butadiene rubber and the like can be exemplified.
[0009]
The vulcanized rubber used as the raw material for powder rubber includes silane coupling agents, sulfur, vulcanizing agents, vulcanization accelerators, vulcanization accelerators, antioxidants, and ozone deterioration inhibitors that are commonly used in the rubber industry. Anti-aging agent, process oil, zinc white (ZnO), stearic acid, peroxide and the like are blended.
[0010]
The present invention is not limited to powder rubber obtained by pulverizing waste tires and tubes made of such vulcanized rubber by conventional methods, but is generated during vulcanization of unvulcanized scraps and tires that are generated during tire production It is also possible to use powder rubber obtained by pulverizing spew pieces.
[0011]
In the present invention, it is possible to increase the surface area without substantially changing the particle size by subjecting the surface of the powder rubber to a roughening process. By using such a powder rubber, a rubber having high destructive properties. A composition is obtained.
[0012]
The method for surface roughening treatment of the present invention is not particularly limited, and specific examples include a method using microorganisms, oxidative decomposition, ozone treatment, plasma treatment and the like. Among these, a method using a microorganism is effective.
[0013]
The microorganism that can be used in the present invention is not particularly limited, but bacteria, actinomycetes, fungi, and white rot fungi are preferable.
Among bacteria, Xantomonas sp., Pseudomonas citronellolis, Pseudomonas aeruginosa are known to degrade natural rubber, and as actinomycetes, Nocardia sp., Nocardia asteroides, Nocardia blasiliensis, Gordona sp. Micromonospora fortuitum, Sreptomyces coelicolor, Actinomyces elastica, Actinomyces fluscus, Proactinomyces ruber, Actinomadura libanotica, Actinoplanes missouriensi, Actinoplanes italicus, Actinoplanes utahensis, Dactylosporangium thailandense, Micromonosptomy Streptomyces atroolivaceus, Streptomyces aureocirculatus, Streptomyces daghestanicus, Streptomyces flavoviridi, Streptomyces fradiae, Streptomyces griseus, Streptomyces griseobrunneus, Streptomyces griseoflavus, Streptomyces griseoflavus, Streptomyces griseovces Many actinomycetes, such as poreus, Streptomyces olivaceus, Streptomyces olivoviridis, Streptomyces tauricus, Amycolatopsis sp. are known to degrade natural rubber. The inventors of the present invention have found that a microorganism belonging to Pseudonocardiaceae, in particular, WU-YS05 strain has a high ability to decompose natural rubber.
The WU-YS05 strain has been deposited at the Patent Organism Depositary of the National Institute of Advanced Industrial Science and Technology under the deposit number FERM P-18660 (Deposit Date: December 21, 2001).
[0014]
As for fungi, Aspergillus sp., Stemphylium macrosporoideum, Paecilomysces lilacinus, Phoma eupyrena, Fusarium solani, Cladosporium cladosporioide are known to degrade natural rubber. Decomposing rubber and synthetic rubbers such as SBR has been reported.
[0015]
In the present invention, these microorganisms can be used alone or in combination. These microorganisms are basically those that can grow using rubber as the sole carbon source, and can be screened and isolated from soil, etc., by creating an environment where rubber is used as the carbon source. . For example, what is shown in Table 1 is illustrated as a liquid culture medium in the case of actinomycetes.
[0016]
[Table 1]
Since there is no carbon source in this medium, for example, by adding a natural rubber sheet to this medium, the above natural rubber-degrading bacteria can be grown and used as seeds for microbial treatment.
[0018]
The method of microbial treatment of powdered rubber in the present invention is not particularly limited. For example, when powdered rubber is added to the above medium and inoculated with a fungus such as a microorganism belonging to Pseudonocardiaceae obtained as an inoculum, the rubber Decomposing microorganisms start to grow using the powder rubber as the sole carbon source, decompose the surface of the powder rubber, and make the surface of the powder rubber uneven.
[0019]
The culture conditions of microorganisms can be normal aerobic microorganism culture conditions. The amount of bacteria per 1000 ml to 100 ml of liquid medium is 1 platinum ear, 1 g to 5 g of powdered rubber, and the culture temperature is room temperature (25 ° C. to 25 ° C. 35 ° C.), and the culture time is 5 to 20 days depending on the degree of the unevenness treatment.
Further, the powder rubber preferably has a particle size of 1 mm or less before the surface roughening treatment, more preferably 0.5 mm or less, further preferably 0.2 mm, particularly preferably 0.1 mm or less. . Even if the particle size is larger, the desired effect can be obtained by making the surface uneven, but by making the surface small to some extent, a powder rubber having a large surface area can be obtained more efficiently.
[0020]
The degree of the surface roughening treatment is not particularly limited and is appropriately selected according to the purpose and application. The degree of unevenness treatment can be determined by the weight change rate of the powder rubber, and the weight change rate of the powder rubber is preferably in the range of 0.1% to 40%.
After culturing, the rubber powder is filtered, washed with an organic solvent and water, dried and used as a raw material for the rubber composition.
[0021]
By blending the surface-treated powder rubber of the present invention, it is possible to obtain a rubber composition having superior fracture characteristics and wear resistance than when using conventional powder rubber. Such a rubber composition is used as a tire. When used as a coating rubber for treads, sidewalls, carcass plies and belt plies, durability can be improved as compared with conventional tires using powder rubber. Further, the gas filled in the tire of the present invention is not limited to air, and an inert gas such as nitrogen can also be used.
[0022]
EXAMPLES Next, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited to the following examples.
[0023]
1. Microorganism screening In 100 ml of the medium shown in Table 1, about 10 mg of soil and acetone-extracted natural rubber latex gloves were cut into 5 cm square rubber pieces, cultured at 30 ° C. for 2 weeks with shaking, and adhered to the surface of the rubber pieces. The bacteria were separated on a solid medium obtained by adding 1.5% by weight of agar to a solution having the same composition as the medium shown in Table 1 to obtain WU-YS05 strain (a microorganism of Pseudonocardiaceae).
[0024]
2. After putting 5 g / l of a commercially available powdered rubber (US Rouse: 200 mesh) in a medium having the composition shown in Table 1 prepared in a glass container with a surface-roughened silicone plug, sterilized in an autoclave at 90 ° C. The WU-YS05 strain was aseptically inoculated with a platinum loop. After culturing at 30 ° C. for 10 days under conditions of 50 to 70 rpm, the rubber powder was filtered with a filter paper. The powder rubber on the filter paper was washed several times with acetone, then washed with pure water, and vacuum dried at 40 ° C. to prepare a powder rubber sample to be blended.
For comparison, the same treatment was performed without inoculating any microorganism strain.
The weight reduction rate (decomposition rate) before and after treatment is 0.8%, but the non-inoculated one is less than 0.1%, and the powder rubber is decomposed by microorganisms. confirmed.
[0025]
3. Surface observation The surface of the powder rubber after drying was observed with a scanning electron microscope (SEM) manufactured by JEOL Ltd .. Compared with the powder rubber treated without inoculation, the powder rubber treated with inoculated Pseudonocardiaceae YS05 strain. It was confirmed that the surface was clearly eroded and the unevenness became fine.
[0026]
4). Evaluation of Recycled Rubber Use the powder rubber obtained with and without inoculation as described above, add the rubber powder and rubber compounding agent obtained to the rubber component of the new material, and mix with 80 ml plastmill. This was kneaded to obtain rubber compositions for treads and sidewalls. This was pressurized at 150 ° C. for 20 minutes to obtain a vulcanized rubber sample.
About this composition, abrasion resistance, a fracture characteristic, and crack growth property were measured, and recycled rubber (surface treatment rubber) was evaluated.
[0027]
1) Preparation of rubber composition The rubber composition for tread is a blending ratio shown in Table 2 with respect to the rubber components of 70 parts by weight of SBR and 30 parts by weight of BR, and the composition for sidewall is natural rubber of the new material. A rubber composition was obtained by blending a compounding agent and powdered rubber at a blending ratio shown in Table 3 with respect to a rubber component of 50 parts by weight and 50 parts by weight of BR.
The amount of powder rubber used is shown in Tables 4 and 5 for each Example and Comparative Example.
[0028]
[Table 2]
[Table 3]
2) Measuring method Wear resistance, fracture characteristics, and crack growth resistance of the above composition were measured by the following methods to evaluate recycled rubber.
For each characteristic, the value of Comparative Example 1 (without using rubber powder, only new rubber) is 100 for treads, and Comparative Example 6 (example of using no rubber rubber) for sidewalls. The value of 100 was expressed as an index. The larger the index, the better the characteristics.
The obtained results are shown in Tables 4 and 5.
[0031]
Fracture characteristics According to JIS K6301-1995, the fracture strength (T B ) was measured and expressed as an index with a control of 100. The larger the value, the better the fracture characteristics.
[0032]
Crack growth resistance The test was conducted in the same manner as in JIS K6301-1995, and the number of bendings when the crack length was 10 mm was measured. The larger the value, the better the crack growth resistance.
[0033]
It was measured by the wear-resistant lambourne wear method. The measurement conditions were a load of 4.5 kg, a grindstone surface speed of 100 m / sec, a test speed of 130 m / sec, a slip rate of 30%, a sandfall amount of 20 g / min, and a measurement temperature of room temperature. The control was shown as an index with 100 as the index. The larger the value, the better the result.
[0034]
[Table 4]
[Table 5]
【The invention's effect】
It can be seen that the destruction physical properties, wear resistance, and crack growth resistance are greatly reduced when the untreated powder rubber or the powder rubber treated with uninoculated bacteria is added to Comparative Example 1 in which no powder rubber is added. On the other hand, it was confirmed that the physical properties were greatly improved by using powder rubber treated by inoculating WU-YS05 strain.
Claims (10)
Priority Applications (1)
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|---|---|---|---|
| JP2002344276A JP4251858B2 (en) | 2001-12-04 | 2002-11-27 | Powdered rubber with an uneven surface, rubber composition and tire using the same |
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| JP2001-370373 | 2001-12-04 | ||
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| JP2002344276A JP4251858B2 (en) | 2001-12-04 | 2002-11-27 | Powdered rubber with an uneven surface, rubber composition and tire using the same |
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