JPH0794547B2 - Modification method of polytetramethylene ether glycol - Google Patents
Modification method of polytetramethylene ether glycolInfo
- Publication number
- JPH0794547B2 JPH0794547B2 JP61082914A JP8291486A JPH0794547B2 JP H0794547 B2 JPH0794547 B2 JP H0794547B2 JP 61082914 A JP61082914 A JP 61082914A JP 8291486 A JP8291486 A JP 8291486A JP H0794547 B2 JPH0794547 B2 JP H0794547B2
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- ptmg
- molecular weight
- exchange resin
- cation exchange
- ether glycol
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、ポリテトラメチレンエーテルグリコール（以
下、PTMGと略す）の改質法に関する。更に詳しくは、PT
MG中の低分子量グリコールを選択的に解重合することに
より低分子量体の少ないPTMGを取得する方法に関する。The present invention relates to a method for modifying polytetramethylene ether glycol (hereinafter abbreviated as PTMG). More details, PT
The present invention relates to a method for obtaining PTMG containing a small amount of low molecular weight substances by selectively depolymerizing low molecular weight glycols in MG.
PTMGは、フルオロスルホン酸等の触媒の存在下、テトラ
ヒドロフラン（以下、THFと略す）を重合することによ
り製造されるが、PTMGの分子量分布あるいは低分子量体
含有量は、触媒、重合温度、時間等の重合条件、重合後
の加水分解、水洗プロセス等によつて左右され、一般に
広い分子量分布を有する。しかし、分子量分布の広いPT
MGを用いたエラストマーは低温での耐屈曲性、耐繰り返
し圧縮性に問題があり、分子量分布の狭いPTMG、特に低
分子量体の少ないPTMGが要望されている。PTMG is produced by polymerizing tetrahydrofuran (hereinafter abbreviated as THF) in the presence of a catalyst such as fluorosulfonic acid. The molecular weight distribution or low molecular weight content of PTMG depends on the catalyst, polymerization temperature, time, etc. It generally has a broad molecular weight distribution depending on the polymerization conditions, hydrolysis after polymerization, washing process, etc. However, PT with a wide molecular weight distribution
Elastomers containing MG have problems in bending resistance and cyclic compression resistance at low temperatures, and there is a demand for PTMGs having a narrow molecular weight distribution, particularly PTMGs having a low molecular weight content.
PTMGを解重合して、分子量分布を改良する方法してはす
でに熱分解させる方法 （Macromol,Chem.81 35〜50p、1965）、漂白土を用い
て、90〜180℃で解重合する方法（特開昭57−10013
2）、ヘテロポリ酸を用いて解重合する方法（特開昭60
−109584）、加圧下、酸を存在させて解重合する方法
（USP.4,115,408）等が知られ、一般にも、硫酸等の強
度と加熱することで解重合することが知られている。As a method for depolymerizing PTMG to improve the molecular weight distribution, it is already pyrolyzed (Macromol, Chem. 81 35-50p, 1965), and depolymerized at 90-180 ° C using bleaching earth ( JP 57-10013
2), a method of depolymerizing using a heteropolyacid (JP-A-60
-109584), a method of depolymerizing in the presence of an acid under pressure (USP.4,115,408), and the like are generally known to depolymerize by heating with the strength of sulfuric acid or the like.
さらに酸型の交叉結合イオン交換樹脂の存在下で約120
〜150℃の温度でPTMGを解重合させて、1.30〜1.70の狭
い分子量分布、約1,600〜3,200の数平均分子量および40
℃において、約4.0〜20ポイズの粘度を有するPTMGに改
質する方法（特公昭57−47687）も知られている。Furthermore, about 120 in the presence of acid-type cross-linked ion exchange resin.
Depolymerization of PTMG at temperatures of ~ 150 ° C gives a narrow molecular weight distribution of 1.30-1.70, number average molecular weight of about 1,600-3,200 and 40
There is also known a method of modifying into PTMG having a viscosity of about 4.0 to 20 poise (° C) (JP-B-57-47687).
しかしながら、当該方法では、約120〜150℃というイオ
ン交換樹脂の耐用温度を越えた温度で反応させるため、
改質したPTMG中に分解した酸成分が混入し、酸価が著し
く高くなつたり、着色するといつた欠点があつた。However, in this method, since the reaction is carried out at a temperature exceeding the durable temperature of the ion exchange resin of about 120 to 150 ° C.,
When the acid component decomposed was mixed into the modified PTMG and the acid value became extremely high, or when it was colored, there were some drawbacks.
本発明は、PTMGを解重合によつて、低分子量体の少ない
PTMGに改質する方法であつて、しかも、PTMGの品質には
ほとんど影響を及ぼさない方法を提供するものである。The present invention uses PTMG by depolymerization to reduce the amount of low molecular weight substances.
It is intended to provide a method for modifying PTMG, which has almost no influence on the quality of PTMG.
本発明の要旨は、PTMGを脱水した多孔質型強酸性陽イオ
ン交換樹脂又は、脱水した多孔質型強酸性陽イオン交換
樹脂及び脱水したゲル型強酸性陽イオン交換樹脂に約90
℃以下の温度で接触させて低分子量グリコールを選択的
に解重合させることを特徴とするPTMGの改質法に存す
る。The gist of the present invention is about 90% for dehydrated porous strong acid cation exchange resin or dehydrated porous strong acid cation exchange resin and dehydrated gel strong acid cation exchange resin.
A method for modifying PTMG is characterized by contacting at a temperature of ℃ or below to selectively depolymerize low molecular weight glycol.
以下、本発明を更に詳細に説明する。Hereinafter, the present invention will be described in more detail.
本発明で使用される原料PTMGは、平均分子量500乃至300
0程度の通常のPTMGであつて、両末端がヒドロキシル基
となつていれば特に制限されない。The raw material PTMG used in the present invention has an average molecular weight of 500 to 300.
There is no particular limitation as long as it is a normal PTMG of about 0 and both ends are hydroxyl groups.
本発明によれば、原料PTMGを脱水した多孔質型強酸性陽
イオン交換樹脂と接触させる。多孔質型強酸性陽イオン
交換樹脂としては、マクロポアーを有する強酸性陽イオ
ン交換樹脂であれば良く、例えば、マクロポアーを有す
るスチレン・ビニルベンゼン共重合体をスルホン化し、
酸型としたものが挙げられる。樹脂の架橋度は特に限定
されるものではなく、通常市販のものが使用でき、具体
的にはDIAION PK−216、DIAION PK−228（三菱化成工
業（株）製）等が挙げられる。これらの樹脂は一般には
Na型で市販されており、希塩酸などを用いて酸型にする
必要があるが、本発明で使用する多孔質型強酸性陽イオ
ン交換樹脂は、酸型とした後、水洗によつて過剰の酸を
洗い流し、更に無水のTHFで洗浄するが、又は加熱等に
より脱水する必要がある。含水状態の樹脂を使用した場
合には、解重合が良好に進行せず、好ましくない。又、
ゲル型の強酸性陽イオン交換樹脂を単独で使用した場合
には、脱水した樹脂を使用しても活性が充分でなく、温
度を上げることにより活性を上げると、樹脂が分解し、
製品PTMGの酸価が上がり好ましくない。脱水した多孔質
型強酸性陽イオン交換樹脂は、一種を単独で使用するこ
とも、又、架橋度の異なる二種以上の脱水した多孔質型
強酸性陽イオン交換樹脂を混合して使用することも可能
である。According to the present invention, porous PTMG obtained by dehydrating the raw material PTMG is used.
Contact with ion exchange resin. Porous strong acid cation
As the exchange resin, a strong acidic cation having macropores is used.
It is sufficient if the resin is an exchange resin, for example, it has macropores.
Sulfonate styrene-vinylbenzene copolymer
An acid type is mentioned. The degree of crosslinking of the resin is particularly limited
However, commercially available products can be used.
DIAION PK-216, DIAION PK-228 (Mitsubishi Kasei
Industry (manufactured by Co., Ltd.) and the like. These resins are generally
It is marketed as Na type and is converted to acid type using dilute hydrochloric acid.
It is necessary to use the porous strongly acidic positive ion used in the present invention.
After changing the acid exchange resin to an acid type, wash it with water to remove excess acid.
Rinse and then wash with anhydrous THF, or for heating etc.
Need more dehydration. If resin containing water is used
In this case, depolymerization does not proceed well, which is not preferable. or,
When using gel type strong acid cation exchange resin alone
Is not sufficiently active even if dehydrated resin is used.
If you increase the activity by increasing the degree, the resin will decompose,
The acid value of the product PTMG increases, which is not preferable. Dehydrated porous
One type of strong acid cation exchange resin can be used alone.
Also, two or more dehydrated porous types with different degrees of crosslinking
It is also possible to mix and use strong acid cation exchange resins
Is.
又、本発明によれば、脱水した多孔質型強酸性陽イオン
交換樹脂に脱水したゲル型の強酸性陽イオン交換樹脂を
併用することも可能である。ゲル型の強酸性陽イオン交
換樹脂は特に限定されるものではなく、例えば、スチレ
ン・ジビニルベンゼン共重合体をスルホン化し、酸型と
したものが挙げられる。樹脂の架橋度は特に限定される
ものではなく、通常市販のものが使用できるが、架橋度
８％以上のゲル型強酸性陽イオン交換樹脂を多孔質型強
酸性陽イオン交換樹脂と併用した場合、特にオリゴマー
の解重合反応の選択性が改善され好ましい。ゲル型強酸
性陽イオン交換樹脂は、多孔質型強酸性陽イオン交換樹
脂と同様に処理し、脱水したものを使用する。According to the present invention, it is also possible to use a dehydrated porous strongly acidic cation exchange resin in combination with a dehydrated gel strongly acidic cation exchange resin. The gel type strong acid cation exchange resin is not particularly limited, and examples thereof include acid type obtained by sulfonation of a styrene / divinylbenzene copolymer. The degree of crosslinking of the resin is not particularly limited, and commercially available ones can be used, but when a gel type strong acidic cation exchange resin having a degree of crosslinking of 8% or more is used in combination with a porous strong acidic cation exchange resin. Especially, the selectivity of the depolymerization reaction of the oligomer is improved, which is preferable. The gel-type strongly acidic cation exchange resin is treated and dehydrated in the same manner as the porous strongly acidic cation exchange resin and used.
PTMGの解重合反応は、約90℃以下で行なわれる。反応温
度が高くなると、イオン交換樹脂の酸成分が製品PTMGに
混入し、酸価が高くなり好ましくない。反応温度は、好
ましくは約50〜80℃程度である。The depolymerization reaction of PTMG is performed at about 90 ° C or lower. When the reaction temperature becomes high, the acid component of the ion exchange resin is mixed in the product PTMG, and the acid value becomes high, which is not preferable. The reaction temperature is preferably about 50-80 ° C.
PTMGの解重合反応は、流通方法、懸濁方式のいずれも可
能である。流通方式の場合には常法に従つて、イオン交
換樹脂を樹脂塔に充填し、所定の温度で、PTMGを通液す
ることにより行なわれる。通液の速度は適宜選定される
が、通常、空間速度0.3〜5hr-1程度である。又、懸濁方
式の場合、PTMGに対する樹脂の使用量は適宜選定される
が、通常PTMGに対し乾燥重量で２〜５重量％使用し、所
定の温度で、撹拌下、PTMGをイオン交換樹脂と接触させ
る。反応時間は任意であるが、通常30分〜５時間程度で
ある。反応後、イオン交換樹脂を分離することにより製
品PTMGを取得する。The depolymerization reaction of PTMG can be performed by either a distribution method or a suspension method. In the case of the flow system, the resin tower is filled with an ion exchange resin and PTMG is passed through the resin tower at a predetermined temperature according to a conventional method. Although the liquid passing speed is appropriately selected, the space velocity is usually about 0.3 to 5 hr -1 . In the case of the suspension system, the amount of the resin used relative to PTMG is appropriately selected, but usually 2 to 5% by weight of dry weight is used relative to PTMG, and PTMG is used as an ion exchange resin at a predetermined temperature under stirring. Contact. The reaction time is arbitrary, but is usually about 30 minutes to 5 hours. After the reaction, the product PTMG is obtained by separating the ion exchange resin.
反応生成物は、条件により異なるが、３〜25重量％のTH
Fを含有する。該THFは減圧下、加熱することにより分離
され、目的とする低分子量体の少ないPTMGが取得され
る。The reaction product varies depending on the conditions, but it is 3 to 25% by weight of TH.
Contains F. The THF is separated by heating under reduced pressure, and the target PTMG with a low amount of low molecular weight substance is obtained.
次に本発明を実施例により更に詳細に説明するが、本発
明はその要旨を越えない限り以下の実施例に限定される
ものではない。Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.
尚、実施例中、低分子量体の含有量は、高速液体クロマ
トグラフイーによつて定量した値であり、又酸価の測定
は、エチルエーテル、エチルアルコール混合液中アルコ
ール性KOHにて滴定して行なつた。In the examples, the content of the low molecular weight substance is a value quantified by high performance liquid chromatography, and the acid value is measured by titration with an alcoholic KOH in a mixed solution of ethyl ether and ethyl alcohol. I did it.
実施例１ 真空乾燥した多孔質型強酸性陽イオン交換樹脂（ダイヤ
イオン PK216,H型，三菱化成工業（株）製、架橋度８
％）を100mlジヤケツト付流通反応器に充填した。平均
分子量750のPTMGを80℃に予熱し、80℃に加熱された流
通反応器に100ml/hrで流通させた。Example 1 Vacuum-dried porous strongly acidic cation exchange resin (diamond
ion PK216, H type, Mitsubishi Kasei Co., Ltd., degree of cross-linking 8
%) Into a flow reactor with a 100 ml jacket. average
Preheat PTMG with a molecular weight of 750 to 80 ° C and use a stream heated to 80 ° C.
It was passed through the through-reactor at 100 ml / hr.
反応液から減圧下でTHF及び副生したわずかな水を留去
したところ、20％の重量減がみられ、得られたPTMGの平
均分子量は990であつた。このPTMG中の低分子量体含有
量を液体クロマトグラフイーにて測定し、原料PTMG中の
含有量及び一般グレードのPTMG1000中の含有量と比較し
た。（表−１） 実施例２ 実施例１と同種のイオン交換樹脂100mlを用い、原料に
平均分子量830のPTMGを用いて65℃で50ml/hrで流通反応
させた。減圧下、THFを留去し、真空乾燥したところ、
平均分子量1,030のPTMGが得られ、12％の重量減がみら
れた。表−２に原料と製品PTMGの分析値を示す。When THF and a small amount of by-produced water were distilled off from the reaction solution under reduced pressure, a weight loss of 20% was observed, and the average molecular weight of the obtained PTMG was 990. The content of low molecular weight substances in this PTMG was measured by liquid chromatography and compared with the content in the raw material PTMG and the content in the general grade PTMG1000. (Table-1) Example 2 100 ml of the same kind of ion exchange resin as in Example 1 was used, and PTMG having an average molecular weight of 830 was used as a raw material to carry out a flow reaction at 65 ° C. at 50 ml / hr. When THF was distilled off under reduced pressure and vacuum drying,
PTMG having an average molecular weight of 1,030 was obtained, and the weight loss was 12%. Table 2 shows the raw material and product PTMG analysis values.
比較例１ 多孔質型のイオン交換樹脂のかわりに脱水したゲル型の
イオン交換樹脂（ダイヤイオン SK−1B,H型，三菱化成
工業（株）製、架橋度８％）100mlを流通反応器に充填
し、平均分子量865のPTMGを80℃で70ml/hrで流通反応さ
せた。減圧乾燥後の製品PTMGの分子量は994で5.7％の重
量減がみられた。製品PTMG中の低分子量体含有量を測定
し、原料PTMG中の含有量及び一般グレードのPTMG1000中
の含有量と比較した。（表−３） 比較例２ 比較例１と同種のイオン交換樹脂100mlを用い、原料に
平均分子量830のPTMGを用いて100℃、100ml/hrで流し
た。減圧下、THFを留去し、真空乾燥したところ、平均
分子量1,130のPTMGが得られた。４量体含有量も原料に
比べて約1/3と減つたものの酸価が0.03mgKOH/gを越え、
着色の傾向も見られた。 Comparative Example 1 Instead of a porous ion exchange resin, a dehydrated gel type resin was used.
Ion exchange resin (Diaion SK-1B, H type, Mitsubishi Kasei
Filling the flow reactor with 100 ml of Kogyo Co., Ltd., crosslinking degree 8%)
Then, PTMG with an average molecular weight of 865 was reacted at 80 ° C at 70 ml / hr.
Let The product PTMG after drying under reduced pressure has a molecular weight of 994 and a weight of 5.7%.
The volume was reduced. Measure the content of low molecular weight substances in the product PTMG
Content in raw PTMG and general grade PTMG1000
Compared with the content of. (Table-3)Comparative Example 2 100 ml of the same kind of ion exchange resin as in Comparative Example 1 was used as a raw material.
Using PTMG with an average molecular weight of 830, run at 100 ° C and 100 ml / hr.
It was When THF was distilled off under reduced pressure and vacuum drying, the average
PTMG having a molecular weight of 1,130 was obtained. Tetramer content as raw material
Compared with about 1/3 reduced, the acid value exceeds 0.03 mg KOH / g,
There was also a tendency to color.
実施例３ 真空乾燥した多孔質型強酸性陽イオン交換樹脂（ダイヤ
イオン PK228,H型，三菱化成工業（株）製、架橋度14
％）50mlと、真空乾燥したゲル型強酸性陽イオン交換樹
脂（ダイヤイオン SK116,H型，三菱化成工業（株）
製、架橋度16％）50mlを二層にして連続反応器に仕込ん
だ。平均分子量750のPTMGを50ml/hrで反応器に流通さ
せ、70℃で反応させた。減圧下、生成したTHFと水を除
去したところ11.5％の重量減がみられ、製品の分子量は
884であつた。含有される低分子量体を分析したとこ
ろ、２量体0.20wt％、３量体0.61wt％、４量体1.76wt％
であつた。Example 3 Vacuum-dried porous strongly acidic cation exchange resin (diamond
ion PK228, H type, manufactured by Mitsubishi Kasei Co., Ltd., cross-linking degree 14
%) 50 ml and vacuum dried gel type strong acid cation exchange resin
Fat (Diaion) SK116, H type, Mitsubishi Kasei Co., Ltd.
Made, crosslinked 16%) 50ml in two layers and charged into a continuous reactor
It is. PTMG with an average molecular weight of 750 was distributed to the reactor at 50 ml / hr.
And reacted at 70 ° C. Remove the generated THF and water under reduced pressure.
When I removed it, the weight loss of 11.5% was observed, and the molecular weight of the product was
It was 884. Analysis of the low molecular weight compounds contained
Filter, dimer 0.20wt%, trimer 0.61wt%, tetramer 1.76wt%
It was.
原料と比較すると、２量体が約1/5、３量体が約1/4、４
量体が1/2と減つていることがわかつた。製品の酸価は
0.01mgKOH/gであつた。Compared to raw materials, dimer is about 1/5, trimer is about 1/4, 4
I knew that the quantity was reduced by half. The acid value of the product is
It was 0.01 mg KOH / g.
実施例４ 実施例３で用いた二元系の触媒と同種の触媒を用いて平
均分子量850のPTMGを50ml/hr70℃で流通反応させた。得
られたPTMGの分子量は980で含有される低分子量体は２
量体0.07wt％、３量体0.35wt％、４量体1.22wt％であつ
た。原料と比較すると２量体が約1/10、３量体が約1/
6、４量体が約1/2になつていた。製品の酸価は0.01mgKO
H/gであつた。Example 4 Using the same type of catalyst as the binary catalyst used in Example 3, PTMG having an average molecular weight of 850 was flow-reacted at 50 ml / hr at 70 ° C. The obtained PTMG has a molecular weight of 980, and the low molecular weight product contained is 2
The content was 0.07 wt% of trimer, 0.35 wt% of trimer, and 1.22 wt% of tetramer. Compared to the raw material, the dimer is about 1/10 and the trimer is about 1 /
The 6-tetramer was about 1/2. The acid value of the product is 0.01 mg KO
It was H / g.
本発明によれば、通常の市販品に比べて、二量体含有
量、三量体含有量が夫々、約1/4程度、四量体含有量が
約1/2程度と低分子量グリコールの含有量の少ないPTMG
を取得することができる。本発明方法に従つて得られた
低分子量グリコールの少ないPTMGは、エラストマー原料
として使用すると得られるエラストマーの低温での耐屈
曲性、耐繰り返し圧縮性が向上し、工業的に極めて有用
である。According to the present invention, compared to the usual commercial products, the dimer content, the trimer content is about 1/4, respectively, the tetramer content of about 1/2 and low molecular weight glycol PTMG with low content
Can be obtained. The PTMG containing a small amount of low-molecular-weight glycol obtained by the method of the present invention is industrially extremely useful because the elastomer obtained when used as an elastomer raw material has improved flex resistance and cyclic compression resistance at low temperatures.
フロントページの続き (56)参考文献 特開 昭50−75697（ＪＰ，Ａ) 北条舒正編「キレート樹脂・イオン交換 樹脂」第146〜147頁1977年８月30日（株) 講談社発行 妹尾学 外２名著「イオン交換」第32〜 33頁1991年４月20日（株）講談社発行 垣花秀武著「最新イオン交換」第６〜７ 頁，（株）廣川書店発行Continuation of the front page (56) References Japanese Patent Laid-Open No. 50-75697 (JP, A) "Chelating Resins / Ion Exchange Resins" edited by Shuzo Hojo, pages 146-147 August 30, 1977, Kodansha Inc. Manabu Senoo Outside two authors "Ion exchange" pages 32-33, published by Kodansha, April 20, 1991 Hidetake Kakihana "Latest ion exchange" pages 6-7, published by Hirokawa Shoten Co., Ltd.
Claims (2)
脱水した多孔質型強酸性陽イオン交換樹脂に約90℃以下
の温度で接触させて、低分子量グリコールを選択的に解
重合させることを特徴とするポリテトラメチレンエーテ
ルグリコールの改質法1. A method for selectively depolymerizing a low molecular weight glycol by contacting dehydrated porous strongly acidic cation exchange resin with polytetramethylene ether glycol at a temperature of about 90 ° C. or less. Modification method of tetramethylene ether glycol
脱水した多孔質型強酸性陽イオン交換樹脂及び脱水した
ゲル型の強酸性陽イオン交換樹脂に約90℃以下の温度で
接触させて低分子量グリコールを選択的に解重合させる
ことを特徴とするポリテトラメチレンエーテルグリコー
ルの改質法。2. A low molecular weight glycol is selected by contacting a dehydrated porous strongly acidic cation exchange resin of polytetramethylene ether glycol and a dehydrated gel strongly acidic cation exchange resin at a temperature of about 90 ° C. or less. A method for modifying polytetramethylene ether glycol, which comprises chemically depolymerizing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61082914A JPH0794547B2 (en) | 1986-04-10 | 1986-04-10 | Modification method of polytetramethylene ether glycol |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61082914A JPH0794547B2 (en) | 1986-04-10 | 1986-04-10 | Modification method of polytetramethylene ether glycol |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62240319A JPS62240319A (en) | 1987-10-21 |
| JPH0794547B2 true JPH0794547B2 (en) | 1995-10-11 |
Family
ID=13787518
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61082914A Expired - Fee Related JPH0794547B2 (en) | 1986-04-10 | 1986-04-10 | Modification method of polytetramethylene ether glycol |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0794547B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100973247B1 (en) * | 2008-09-01 | 2010-07-30 | 주식회사 효성 | Depolymerization of Polytetramethylene glycol |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1029881B1 (en) * | 1992-10-21 | 2004-05-12 | E.I. Du Pont De Nemours And Company | Depolymerization to cyclic ethers using selected metal compound catalysts |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3925484A (en) * | 1973-11-08 | 1975-12-09 | Du Pont | Process for making polytetramethylene ether glycol having a narrow molecular weight distribution |
-
1986
- 1986-04-10 JP JP61082914A patent/JPH0794547B2/en not_active Expired - Fee Related
Non-Patent Citations (3)
| Title |
|---|
| 北条舒正編「キレート樹脂・イオン交換樹脂」第１４６〜１４７頁１９７７年８月３０日（株）講談社発行 |
| 垣花秀武著「最新イオン交換」第６〜７頁，（株）廣川書店発行 |
| 妹尾学外２名著「イオン交換」第３２〜３３頁１９９１年４月２０日（株）講談社発行 |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100973247B1 (en) * | 2008-09-01 | 2010-07-30 | 주식회사 효성 | Depolymerization of Polytetramethylene glycol |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62240319A (en) | 1987-10-21 |
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