JPS6141923B2 - - Google Patents
Info
- Publication number
- JPS6141923B2 JPS6141923B2 JP52026335A JP2633577A JPS6141923B2 JP S6141923 B2 JPS6141923 B2 JP S6141923B2 JP 52026335 A JP52026335 A JP 52026335A JP 2633577 A JP2633577 A JP 2633577A JP S6141923 B2 JPS6141923 B2 JP S6141923B2
- Authority
- JP
- Japan
- Prior art keywords
- saponification
- degree
- methanol
- pvac
- minutes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 162
- 238000007127 saponification reaction Methods 0.000 claims description 94
- 229920002689 polyvinyl acetate Polymers 0.000 claims description 54
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 40
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 40
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 32
- 238000000034 method Methods 0.000 claims description 20
- 239000003054 catalyst Substances 0.000 claims description 8
- 239000003513 alkali Substances 0.000 claims description 7
- 239000011118 polyvinyl acetate Substances 0.000 claims description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 78
- 238000001879 gelation Methods 0.000 description 30
- 239000000499 gel Substances 0.000 description 20
- 238000006116 polymerization reaction Methods 0.000 description 13
- 238000006243 chemical reaction Methods 0.000 description 12
- 238000009826 distribution Methods 0.000 description 7
- 239000000155 melt Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- LMDIPIJNHNGUJP-UHFFFAOYSA-N disodium methanol oxygen(2-) Chemical compound CO.[O-2].[Na+].[Na+] LMDIPIJNHNGUJP-UHFFFAOYSA-N 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- VIKNJXKGJWUCNN-XGXHKTLJSA-N norethisterone Chemical compound O=C1CC[C@@H]2[C@H]3CC[C@](C)([C@](CC4)(O)C#C)[C@@H]4[C@@H]3CCC2=C1 VIKNJXKGJWUCNN-XGXHKTLJSA-N 0.000 description 4
- 230000035484 reaction time Effects 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- GRONZTPUWOOUFQ-UHFFFAOYSA-M sodium;methanol;hydroxide Chemical compound [OH-].[Na+].OC GRONZTPUWOOUFQ-UHFFFAOYSA-M 0.000 description 3
- 238000001035 drying Methods 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 239000004831 Hot glue Substances 0.000 description 1
- 125000000218 acetic acid group Chemical group C(C)(=O)* 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000012768 molten material Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000005809 transesterification reaction Methods 0.000 description 1
Landscapes
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Description
【発明の詳細な説明】
本発明はポリ酢酸ビビニル(以下PVAcと略
す。)のケン化方法に関するものであり、さらに
詳しくはPVAcのメタノール溶液にアルカリ触媒
を添加してケン化し、ケン化度80モル%以下のポ
リビニルアルコール(以下PVAと略す。)を製造
するに際し、メタノールの含水率を0.05〜0.8重
量%に保ち、該メタノールの量を所定ケン化度の
PVAを得るに必要な化学量論的量の2倍重量な
いし3.5倍重量になるように調節することによつ
てケン化度を制御することを特徴とするPVAcの
ケン化方法である。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for saponifying polyvinyl acetate (hereinafter abbreviated as PVAc), and more specifically, the present invention relates to a method for saponifying polyvinyl acetate (hereinafter abbreviated as PVAc). When producing polyvinyl alcohol (hereinafter abbreviated as PVA) of mol% or less, the water content of methanol is maintained at 0.05 to 0.8% by weight, and the amount of methanol is adjusted to a predetermined degree of saponification.
This is a PVAc saponification method characterized by controlling the degree of saponification by adjusting the weight to be 2 to 3.5 times the stoichiometric amount required to obtain PVA.
従来から、PVAの工業的製造方法としては一
般にPVAcを所定ケン化度のPVAを得るに必要な
化学量論的量の4倍重量以上の無水または含水ア
ルコール溶液となし、これにアルカリ触媒を添加
してケン化したのち分離、乾燥する方法が採用さ
れている。しかるにこの場合、PVAcのケン化工
程において製品のケン化度を制御することが非常
に困難であり、特に低ケン化度PVAを再現よく
安定に製造することは至難のことであつて、これ
まで最も改善が望まれていたものである。すなわ
ち、PVAのケン化度を制御する方法としてケン
化触媒として使用するアルカリ量および反応時間
を調節する方法が採られているが、ケン化度80モ
ル%以下の低ケン化度のPVAを得ようとしてア
ルカリ量を少なくすると反応時間が極度に長くな
つて生産量を上げることができないため、工業的
に不利になるばかりか、やはりこの場合でも4倍
重量以上のアルコールが存在するとゲル化後ケン
化度50モル%付近から10モル%付近までの反応速
度勾配はかなり急であり、従つてこの間の任意の
ケン化度のPVAを再現よく得ることは極めて困
難なことである。また、このケン化度を制御する
別の方法として反応の途中に酸または水を加える
方法も提案されているが、前述の如く4倍重量以
上のアルコール存在下では反応速度勾配が急であ
るため、酸または水の添加時期を少し誤まるとケ
ン化度は所定の値を大きくはずれることになり、
これを防ぐことは極めて精密な制御装置をもつて
しても困難なことである。また、水を加える方法
については酸と同様の煩雑さのほか添加した水が
アルコールに対し0.8重量%をこえると添加した
水にPVAが溶解するため最終製品としてのPVA
の乾燥が極めて困難となり、この傾向は低重合度
並びに低ケン化度の場合にとくに著しい。 Traditionally, the industrial method for producing PVA has generally been to prepare an anhydrous or hydrous alcohol solution of PVAc at least four times the weight of the stoichiometric amount required to obtain PVA with a predetermined degree of saponification, and then add an alkaline catalyst to this solution. The method used is to saponify it, then separate it and dry it. However, in this case, it is extremely difficult to control the degree of saponification of the product in the saponification process of PVAc, and it is especially difficult to stably produce PVA with a low saponification degree with good reproducibility. This is what was most desired to be improved. In other words, the method of controlling the saponification degree of PVA is to adjust the amount of alkali used as a saponification catalyst and the reaction time, but it is difficult to obtain PVA with a low saponification degree of 80 mol% or less. However, if the amount of alkali is reduced in the process, the reaction time becomes extremely long and production cannot be increased, which is not only disadvantageous industrially, but also in this case, if more than 4 times the weight of alcohol is present, the quenching after gelation will occur. The reaction rate gradient from around 50 mol% to around 10 mol% is quite steep, and therefore it is extremely difficult to reproducibly obtain PVA with any saponification degree between this range. In addition, as another method to control the degree of saponification, a method of adding acid or water during the reaction has been proposed, but as mentioned above, the reaction rate gradient is steep in the presence of 4 times the weight or more of alcohol. If the timing of addition of acid or water is slightly incorrect, the degree of saponification will deviate significantly from the specified value.
It is difficult to prevent this even with extremely precise control equipment. In addition, the method of adding water is complicated, as is the case with acids, and if the added water exceeds 0.8% by weight based on the alcohol, PVA will dissolve in the added water, so PVA as a final product
It becomes extremely difficult to dry the polymer, and this tendency is particularly remarkable when the degree of polymerization and saponification is low.
本発明者らは上述のようなPVA製造上の欠点
を克服し、特にケン化度80モル%以下の低ケン化
度PVAを再現よく安定に製造する方法として、
PVAcの無水メタノール溶液にアルカリ触媒を添
加しPVMcをケン化してPVAを製造する方法にお
いて、所定のケン化度のPVAを得るに必要な化
学量論的量と同重量ないし2倍重量のメタノール
にPVAcを溶解してケン化すれば所期のケン化度
に容易に制御することができることを見出しすで
に出願した(特開昭51―87593号)。 The present inventors have overcome the above-mentioned disadvantages in PVA production, and developed a method for stably producing PVA with a low saponification degree of 80 mol% or less with good reproducibility.
In the method of producing PVA by adding an alkaline catalyst to an anhydrous methanol solution of PVAc and saponifying PVMc, methanol is added to the same weight or twice the weight of the stoichiometric amount required to obtain PVA with a predetermined degree of saponification. It was discovered that the degree of saponification could be easily controlled by dissolving and saponifying PVAc, and an application has already been filed (Japanese Patent Application Laid-Open No. 87593/1983).
しかしながら、この方法ではケン化度は極めて
正確かつ再現性よく調節できる反面、得られた
PVAcの溶融粘度が比較的高くなる欠点があつ
た。これは、実質的に無水の状態でケン化が行わ
れるために残存酢酸基の分子内分布がより集団的
になるためであると考えられる。さらに、第2の
欠点として、ケン化を行う際のポリマー濃度が高
くなりすぎるために、触媒のアルカリとPVAcと
の混合を均一に行いにくく、そのためかケン化度
の分子間分布が広くなりすぎることが分かつた。 However, while this method allows the degree of saponification to be adjusted extremely accurately and reproducibly, the
The disadvantage was that the melt viscosity of PVAc was relatively high. This is considered to be because the saponification is carried out in a substantially anhydrous state, so that the intramolecular distribution of residual acetic acid groups becomes more collective. Furthermore, the second drawback is that the polymer concentration during saponification becomes too high, making it difficult to mix the alkali catalyst and PVAc uniformly, and perhaps because of this, the intermolecular distribution of the degree of saponification becomes too wide. I found out.
かかる欠点を克復するために、本発明者らは引
き続き鋭意研究を重ねた結果、特にケン化度80モ
ル%以下のPVAを製造するに際し、含水率0.05〜
0.8重量%に保つたメタノールにPVAcを溶解し、
そのメタノール量を所定ケン化度を得るに必要な
化学量論的量の2倍重量ないし3.5倍重量に調節
することによつて、かかる品質上の問題点を解決
しつつ、ケン化度を精度よく調節し得ることを見
出し、本発明を完成するに至つた。 In order to overcome these drawbacks, the present inventors continued to conduct intensive research and found that, in particular, when producing PVA with a degree of saponification of 80 mol% or less, the water content is 0.05 to 0.05.
Dissolve PVAc in methanol kept at 0.8% by weight,
By adjusting the amount of methanol to 2 times to 3.5 times the weight of the stoichiometric amount required to obtain a predetermined degree of saponification, the degree of saponification can be accurately adjusted while solving such quality problems. They have found that it can be well adjusted and have completed the present invention.
PVAcのメタノール溶液の工業的ケン化反応に
は主としてアルカリ触媒が使用されるが、たとえ
ば無水メタノール中で水酸化ナトリウムを使用し
た場合の反応機構は次のようなエステル交換反応
が主体となる。 Alkali catalysts are mainly used in the industrial saponification reaction of methanol solutions of PVAc. For example, when sodium hydroxide is used in anhydrous methanol, the reaction mechanism is mainly the transesterification reaction described below.
ここでnはモル数を表わす任意の正数、aは0
≦a≦1であり、ケン化度a×100(モル%)で
表示される。したがつて、ケン化度a×100モル
%のPVAを製造するための無水メタノールの化
学量論的量はanモルであり、これだけの量の無
水メタノールが存在すれば理論的にはよいことに
なる。しかるに系内に過剰の無水メタノールが存
在する場合には所定ケン化度にて反応を停止せし
めることが困難となる。過剰無水メタノール量を
mモルとすると(an+m)/an>2になると特
にこの傾向が大きくなる。工業的には(an+
m)/anが4以上の条件で行われることが多
く、このため前述のような障害が非常に大きく、
所定の低ケン化度で反応を再現性よく停止するこ
とができないのである。 Here, n is any positive number representing the number of moles, a is 0
≦a≦1, and the degree of saponification is expressed as a×100 (mol%). Therefore, the stoichiometric amount of anhydrous methanol to produce PVA with saponification degree a x 100 mol% is an mole, and it is theoretically good if this amount of anhydrous methanol exists. Become. However, if an excess of anhydrous methanol is present in the system, it becomes difficult to stop the reaction at a predetermined degree of saponification. This tendency becomes particularly strong when (an+m)/an>2, assuming that the amount of excess anhydrous methanol is mmol. Industrially (an+
m)/an is often 4 or more, and for this reason, the above-mentioned obstacles are very large.
The reaction cannot be stopped with good reproducibility at a predetermined low degree of saponification.
本発明者らが無水メタノールを使用した場合1
≦(an+m)/an≦2の範囲でケン化度の制御が
容易であることを見出し、先に特開昭51―087593
号に出願したことは前述の通りである。 When the present inventors use anhydrous methanol 1
It was discovered that the degree of saponification can be easily controlled within the range of ≦(an+m)/an≦2, and was previously published in JP-A-51-087593.
As mentioned above, the application was filed under No.
しかし、この方法では前述のごとくPVAの
溶融粘度が高くなる、ケン化度の分子間分布が
広くなるという2つの欠点があつた。これらはそ
のPVAをホツトメルト接着剤として利用する際
に大きな障害となるものであつて、の場合は糊
付時の作業性が悪くなり、の場合は接着剤の耐
湿性が悪くなり、いずれも商品としては好ましく
ない性質のものである。 However, as mentioned above, this method has two drawbacks: the melt viscosity of PVA increases and the intermolecular distribution of saponification degree widens. These are major obstacles when using PVA as a hot melt adhesive. It has an unfavorable property.
本発明の方法によつてこれらの欠点は克服さ
れ、かつケン化度を再現性よく制御することが可
能となつた。すなわち、水の存在下にケン化を行
うと系の誘電率が上昇するために、ポリマー分子
鎖にそつて触媒のアルカリが広がりをもつて攻撃
しうるようになつたためか、残存酢酸基の分子内
分布が均一なPVAが得られ、このものはそうで
ないものに比べ溶融粘度が低くなる。また、水を
加えることによつてケン化反応速度が遅くなるた
めにある程度メタノールの量を増やしてもケン化
度を再現性よく調節し得るようになり、メタノー
ルの量を増やすとPVAcの濃度が減少する結果、
溶液粘度が下がり、アルカリとの混合性が良くな
つたためかケン化度の分子間分布が狭いPVAが
得られる。 The method of the present invention overcomes these drawbacks and makes it possible to control the degree of saponification with good reproducibility. In other words, when saponification is carried out in the presence of water, the dielectric constant of the system increases, and the alkali of the catalyst spreads along the polymer molecular chain and becomes able to attack. A PVA with uniform internal distribution is obtained, which has a lower melt viscosity than one without. In addition, adding water slows down the saponification reaction rate, so even if the amount of methanol is increased to a certain extent, the degree of saponification can be adjusted with good reproducibility. As a result of decreasing
PVA with a narrow intermolecular distribution of degree of saponification is obtained, probably due to lower solution viscosity and improved miscibility with alkali.
このように、ケン化度80モル%以下のPVAを
製造するに際し、水の作用効果を巧みに利用し、
なおかつメタノールの量を調節することによつて
品質を高度に保ちながらケン化度を精度よく制御
することがはじめて可能となつた。しかしなが
ら、水の量は少なすぎると効果が出ず、多すぎる
と乾燥が困難になるばかりか、所定のケン化度を
得るためにより多量のアルカリ触媒が必要とな
り、その結果、副生する酢酸塩の影響でPVAの
熱安定性が悪くなる。したがつて、水の量には自
ら制限があり、メタノールに対し0.05〜0.8重量
%の範囲であることが必要である。 In this way, when producing PVA with a saponification degree of 80 mol% or less, we skillfully utilize the effects of water.
Furthermore, by adjusting the amount of methanol, it became possible for the first time to precisely control the degree of saponification while maintaining a high level of quality. However, if the amount of water is too small, it will not be effective, and if it is too large, not only will drying become difficult, but a larger amount of alkaline catalyst will be required to obtain the desired degree of saponification, resulting in acetate being produced as a by-product. The thermal stability of PVA deteriorates due to the influence of Therefore, the amount of water has its own limitations and needs to be in the range of 0.05 to 0.8% by weight based on methanol.
第1図は平均重合度120のPVAcを0.5重量%含
水メタノール溶液でケン化する際のPVAc濃度と
ケン化度の関係を示すものである。第1図におい
て曲線1は縦軸に示したケン化度のPVAを得る
に必要な化学量論的量の2倍重量のメタノールに
PVAcを溶解した場合の溶液のPVAc濃度をケン
化度の関係を示したものであり、曲線2は同様に
化学量論的量の3.5倍重量のメタノールに溶解し
た場合の関係曲線である。したがつて、本発明の
ケン化方法に際しPVAc/メタノールの調節範囲
は曲線1と曲線2によつて囲まれた部分である。 FIG. 1 shows the relationship between the PVAc concentration and the degree of saponification when PVAc having an average degree of polymerization of 120 is saponified with a 0.5% by weight aqueous methanol solution. In Figure 1, curve 1 indicates that the amount of methanol that is twice the stoichiometric amount required to obtain PVA with the degree of saponification indicated on the vertical axis is
This graph shows the relationship between the PVAc concentration in a solution and the degree of saponification when PVAc is dissolved, and curve 2 is a relationship curve when PVAc is similarly dissolved in 3.5 times the stoichiometric amount of methanol. Therefore, the adjustment range of PVAc/methanol in the saponification method of the present invention is the area surrounded by curve 1 and curve 2.
また、第1図において曲線3は水酸化ナトリウ
ムを5ミリ当量添加し、温度40℃でケン化したと
きの関係曲線であり、曲線4は同様に水酸化ナト
リウムを10ミリ当量添加して行つた場合の関係曲
線である。曲線3および4の条件における反応時
間はそれぞれゲル化後60分以上経過したものであ
り、これ以上放置してもさらに反応が進行するこ
とのない、すなわち反応の飽和点を示すものであ
る。 In addition, in Figure 1, curve 3 is the relationship curve when 5 milli equivalents of sodium hydroxide is added and saponification is carried out at a temperature of 40°C, and curve 4 is the relationship curve when 10 milli equivalents of sodium hydroxide is added. This is the relationship curve for the case. The reaction time under the conditions of curves 3 and 4 is 60 minutes or more after gelation, and indicates that the reaction does not proceed further even if left for any longer, that is, the saturation point of the reaction.
第2図は重合度120のPVAcを(an+m)/an
=3になるように各含水率のメタノールで溶解
し、温度40℃で水酸化ナトリウムをPVAcに対し
5ミリ当量添加してケン化した場合のケン化度の
経時変化を示したものである。第2図から含水率
が0.02重量%ではゲル化後もケン化反応が進行
し、時間とともにケン化度が上昇するが、含水率
が0.05重量%以上になるとゲル化後60分以上経過
してもケン化度の上昇は小さく、ほぼ反応が停止
していることがわかる。含水率が0.8重量%にな
るとケン化反応はゲル化後60分経過するとほぼ完
全に停止していることがわかる。 Figure 2 shows PVAc with a degree of polymerization of 120 (an+m)/an
This figure shows the change over time in the degree of saponification when PVAc was dissolved in methanol with various water contents such that PVAc = 3, and saponified by adding 5 milli equivalents of sodium hydroxide to PVAc at a temperature of 40°C. Figure 2 shows that when the water content is 0.02% by weight, the saponification reaction continues even after gelation, and the degree of saponification increases with time, but when the water content is 0.05% by weight or more, more than 60 minutes have passed after gelation. It can be seen that the increase in the degree of saponification was small, indicating that the reaction had almost stopped. It can be seen that when the water content reaches 0.8% by weight, the saponification reaction almost completely stops 60 minutes after gelation.
第3図は含水率0.5重量%のメタノールにPVAc
を(an+m)/anの比が5〜2になるように溶
解し、温度40℃で水酸化ナトリウム5ミリ当量用
いてケン化た場合に生成するPVAのケン化度の
時間経過を示したものである。第3図から(an
+m)/an=5ではゲル化後60分経過した後も
ケン化反応が進行していることがわかる。これに
対し(an+m)/an=3.5および2.0では60分経過
後のケン化反応はほぼ完全に停止していることが
明らかである。 Figure 3 shows PVAc in methanol with a moisture content of 0.5% by weight.
This graph shows the time course of the degree of saponification of PVA produced when PVA is dissolved at a ratio of (an+m)/an of 5 to 2 and saponified using 5 milliquivalents of sodium hydroxide at a temperature of 40°C. It is. From Figure 3 (an
+m)/an=5, it can be seen that the saponification reaction continues even after 60 minutes have passed after gelation. On the other hand, when (an+m)/an=3.5 and 2.0, it is clear that the saponification reaction has almost completely stopped after 60 minutes.
第2図および第3図からメタノール量が(an
+m)/an≧2で含水率の低い場合、すなわ
ち、含水率0.02%の無水メタノール溶液でPVAc
をケン化する場合および含水率0.5%含水メタノ
ールでも(an+m)an≧4でケン化する場合に
は、たとえばケン化度60モル%でコントロールし
ようとすれば反応時間約20分の時点で瞬間的に反
応を停止させねばならないことが明らかである
が、実際には工業的規模での製造に際し、この反
応の制御は非常に困難である。しかるに、2≦
(an+m)/an≦3.5の範囲の含水率0.05〜0.8重
量%のメタノールに溶解したPVAcのケン化反応
は所定のケン化度で反応を停止することが容易で
あるから、本発明の方法は低ケン化度のPVAの
製造に非常に有効である。 From Figures 2 and 3, the amount of methanol (an
+m)/an≧2 and the water content is low, i.e. PVAc in an anhydrous methanol solution with a water content of 0.02%.
When saponifying aqueous methanol with a water content of 0.5% (an+m)an≧4, for example, if you try to control the degree of saponification at 60 mol%, the reaction time will be instantaneous at about 20 minutes. Although it is clear that the reaction must be stopped immediately, it is actually very difficult to control this reaction during production on an industrial scale. However, 2≦
Since the saponification reaction of PVAc dissolved in methanol with a water content of 0.05 to 0.8% by weight in the range of (an+m)/an≦3.5 can be easily stopped at a predetermined degree of saponification, the method of the present invention It is very effective in producing PVA with a low degree of saponification.
本発明の方法はケン化度の制御に有用で、種々
の重合度およびケン化度のPVAの製造に有効で
あるが、PVAcをメタノールに溶解した溶液の粘
度が高くなり過ぎると反応が不均一になり易く操
作も困難となるので、特に50〜700の低重合度で
80モル%以下の低ケン化度のPVAを得るのにも
つとも適している。 The method of the present invention is useful for controlling the degree of saponification and is effective for producing PVA with various degrees of polymerization and saponification. However, if the viscosity of a solution of PVAc dissolved in methanol becomes too high, the reaction may be uneven. This is especially true at low polymerization degrees of 50 to 700.
It is also suitable for obtaining PVA with a low saponification degree of 80 mol% or less.
本発明の方法を遂行する有効なケン化装置とし
てはバツチ式の場合にはニーダー型、連続式の場
合はベルト型、パイプ型、二軸スクリユー型等を
挙げることができ、本発明の方法はこれら公知の
装置のいずれを用いても良好な結果が得られる。 Effective saponification devices for carrying out the method of the present invention include a kneader type in the case of a batch type, and a belt type, pipe type, twin screw type, etc. in the case of a continuous type. Good results can be obtained using any of these known devices.
次に実施例を示し、本発明をさらに詳細に説明
する。なお、実施例中、単に部とあるのはいずれ
も重量部を表す。 EXAMPLES Next, the present invention will be explained in further detail by way of examples. In addition, in the examples, all parts simply refer to parts by weight.
実施例 1
ケン化度60.0モル%のPVAを得ることを目的と
して平均重合度120のPVAc69.1部を含水率0.5重
量%のメタノール27.86部に溶解し、温度を40℃
に保つて5重量%の水酸化ナトリウムメタノール
溶液3.37部を添加し、5分間撹拌したのちそのま
ま放置した。水酸化ナトリウム添加後15分経過し
たときゲル化が起こつた。Example 1 In order to obtain PVA with a saponification degree of 60.0 mol%, 69.1 parts of PVAc with an average degree of polymerization of 120 was dissolved in 27.86 parts of methanol with a water content of 0.5% by weight, and the temperature was adjusted to 40°C.
3.37 parts of a 5% by weight methanol solution of sodium hydroxide was added thereto, and after stirring for 5 minutes, the mixture was left to stand. Gelation occurred 15 minutes after the addition of sodium hydroxide.
ゲル化後60分経過したところでゲルの一部を取
り出し粉砕後80℃、圧力5mmHgで2時間減圧乾
燥してケン化度を測定したところ、ケン化度は
60.5モル%であつた。また、該ゲルをさらに60分
間すなわちゲル化後120分間放置したのちゲルの
一部を取り出し同様に操作したところケン化度の
進行は認められなかつた。 60 minutes after gelation, a part of the gel was taken out, crushed, and dried under reduced pressure at 80°C and 5 mmHg for 2 hours to measure the degree of saponification.
It was 60.5 mol%. Further, after the gel was left to stand for an additional 60 minutes, ie, 120 minutes after gelation, a portion of the gel was taken out and operated in the same manner, and no progress in the degree of saponification was observed.
本条件におけるメタノール量(an+m)/an
は2倍、水酸化ナトリウムはPVAcに対し5.25ミ
リ当量である。 Amount of methanol under these conditions (an+m)/an
is twice as high, and sodium hydroxide is 5.25 milliequivalents to PVAc.
比較のため、同一のPVAc52.8部を含水率0.5重
量%のメタノール44.99部に溶解し、40℃にして
5重量%水酸化ナトリウムメタノール溶液2.45部
加えてケン化したところ18分後にゲル化が起こつ
た。ゲル化後20分間経過した時点でゲルの一部を
取り出し同様に処理してケン化度を測定したとこ
ろ、ケン化度は59.5モル%であつた。しかしそれ
から10分放置(ゲル化30分)したゲルを処理した
場合のケン化度は65.0モル%であり、さらに10分
放置(ゲル化後40分)したゲルを処理するとその
ケン化度は68.4モル%であつた。この場合のメタ
ノール量(an+m)/anは4.0 水酸化ナトリウ
ムは5.25ミリ当量であつた。 For comparison, 52.8 parts of the same PVAc was dissolved in 44.99 parts of methanol with a water content of 0.5% by weight, and 2.45 parts of a 5% by weight methanol solution of sodium hydroxide was saponified at 40°C. After 18 minutes, gelation occurred. It happened. After 20 minutes had elapsed after gelation, a portion of the gel was taken out and treated in the same manner to measure the degree of saponification, which was found to be 59.5 mol%. However, when a gel that was left for 10 minutes (30 minutes after gelation) was processed, the degree of saponification was 65.0 mol%, and when a gel that was left for another 10 minutes (40 minutes after gelation) was processed, the degree of saponification was 68.4. It was mol%. In this case, the amount of methanol (an+m)/an was 4.0, and the amount of sodium hydroxide was 5.25 meq.
実施例 2
ケン化度60.0モル%のPVAを得ることを目的と
して平均重合度250のPVAc64.2部を含水率0.5重
量%のメタノール29.58部に溶解し、温度40℃に
保つて5重量%水酸化ナトリウムメタノール溶液
6.74部を添加し、5分間撹拌したのちそのまま放
置した。水酸化ナトリウム添加後12分経過したの
ちゲル化が起こつた。ゲル化後60分経過した時点
と90分経過した時点において実施例1と同様の方
法でゲルを処理したのちそのケン化度を測定した
結果、ケン化度はそれぞれ60.3モル%および60.0
モル%であつた。このときメタノール量は(an
+m)/an=2.5、水酸化ナトリウムはPVAcに対
し11.3ミリ当量であつた。Example 2 In order to obtain PVA with a saponification degree of 60.0 mol%, 64.2 parts of PVAc with an average degree of polymerization of 250 was dissolved in 29.58 parts of methanol with a water content of 0.5% by weight, and the mixture was kept at a temperature of 40°C and dissolved in 5% by weight water. sodium oxide methanol solution
6.74 parts were added, stirred for 5 minutes, and left as it was. Gelation occurred 12 minutes after the addition of sodium hydroxide. The gel was treated in the same manner as in Example 1 at 60 minutes and 90 minutes after gelation, and the degree of saponification was measured. As a result, the degree of saponification was 60.3 mol% and 60.0, respectively.
It was mol%. At this time, the amount of methanol is (an
+m)/an=2.5, and sodium hydroxide was 11.3 milliequivalents to PVAc.
また、ゲル化後90分経過した時点におけるゲル
を取り出し、常圧下105℃で60分間乾燥したのち
180℃で溶融したところ、溶融粘度は35000センチ
ポイズであつた。 In addition, after 90 minutes had passed after gelation, the gel was taken out and dried at 105°C under normal pressure for 60 minutes.
When melted at 180°C, the melt viscosity was 35,000 centipoise.
比較のため、同じPVAc64.2部を含水率0.02重
量%のメタノール29.47部に溶解し、同様に処理
したところ水酸化ナトリウムの添加後10分でゲル
化が起こり、ゲル化後5分経過したところのケン
化度は59.6モル%であつたが、さらに10分間放置
したゲルの場合にはケン化度は72.0モル%となつ
た。 For comparison, when 64.2 parts of the same PVAc was dissolved in 29.47 parts of methanol with a moisture content of 0.02% by weight and treated in the same way, gelation occurred 10 minutes after adding sodium hydroxide, and 5 minutes after gelation. The degree of saponification was 59.6 mol%, but when the gel was left to stand for an additional 10 minutes, the saponification degree was 72.0 mol%.
また、ゲル化後5分経過した時点のゲルを取り
出し酢酸で中和してゲル化の進行を抑えたのち、
常圧下105℃で60分間乾燥し180℃で溶融粘度を測
定したところ、68000センチポイズであつた。 In addition, after 5 minutes had passed after gelation, the gel was taken out and neutralized with acetic acid to suppress the progress of gelation.
The melt viscosity was measured at 180°C after drying at 105°C for 60 minutes under normal pressure and found to be 68,000 centipoise.
実施例 3
ケン化度40.0モル%のPVAを得ることを目的と
して平均重合度490のPVAc65.7部を含水率0.5重
量%のメタノール31.27部に溶解し、温度40℃に
保つて5重量%水酸化ナトリウムメタノール溶液
3.37部添加し、5分間撹拌しそのまま放置した。
水酸化ナトリウム添加後14分経過したのちゲル化
が起こつたが、ゲル化後60分経過した時点と120
分経過した時点において、ゲルを実施例1と同様
の方法で処理したのちそのケン化度を測定したと
ころ、ケン化度はそれぞれ39.5モル%および41.2
モル%であつた。このときのメタノール量(an
+m)/anは3.5、水酸化ナトリウムはPVAcに対
し5.51ミリ当量であつた。Example 3 In order to obtain PVA with a saponification degree of 40.0 mol%, 65.7 parts of PVAc with an average degree of polymerization of 490 was dissolved in 31.27 parts of methanol with a water content of 0.5% by weight, and the mixture was kept at a temperature of 40°C and dissolved in 5% by weight water. sodium oxide methanol solution
3.37 parts were added, stirred for 5 minutes, and left as it was.
Gelation occurred 14 minutes after the addition of sodium hydroxide, but at 60 minutes and 120 minutes after gelation.
After a few minutes had elapsed, the gel was treated in the same manner as in Example 1 and its saponification degree was measured, and the saponification degree was 39.5 mol% and 41.2 mol%, respectively.
It was mol%. The amount of methanol at this time (an
+m)/an was 3.5, and sodium hydroxide was 5.51 milliequivalent to PVAc.
比較のため、同じPVAc59.9部を含水率0.5重量
%のメタノール37.4部に溶解し、40℃で5重量%
水酸化ナトリウムメタノール溶液3.07部加え同様
に処理したところ、水酸化ナトリウム添加後12分
後にゲル化が起こり、ゲル化後5分経過した時点
のゲルを取り出し、同様に処理して測定したとこ
ろケン化度は50.6モル%であり、すでに目的の
40.0モル%をはるかに越えていた。この場合のメ
タノール量(an+m)/anは4.5、水酸化ナトリ
ウムはPVAcに対し5.51ミリ当量であつた。 For comparison, 59.9 parts of the same PVAc was dissolved in 37.4 parts of methanol with a moisture content of 0.5% by weight, and the mixture was heated to 5% by weight at 40°C.
When 3.07 parts of sodium hydroxide methanol solution was added and treated in the same way, gelation occurred 12 minutes after adding sodium hydroxide.The gel was taken out 5 minutes after gelation, treated in the same way, and measured. The degree is 50.6 mol%, which is already the target
It far exceeded 40.0 mol%. In this case, the amount of methanol (an+m)/an was 4.5, and the amount of sodium hydroxide was 5.51 milliequivalent to PVAc.
実施例 4
ケン化度75.0モル%のPVAを得ることを目的と
して平均重合度300のPVAc65.7部を含水率0.06重
量%のメタノール37.3部に溶解し、温度40℃に保
つて5重量%水酸化ナトリウムメタノール溶液
1.22部を添加し、5分間撹拌しそのまま放置し
た。水酸化ナトリウム添加後20分したのちゲル化
が起こつたが、ゲル化後60分経過した時点と120
分経過した時点においてゲルを実施例1と同様の
方法で処理したところ、ケン化度はそれぞれ75.2
モル%及び76.5モル%であつた。このとき、上記
それぞれの時点について、ゲルの任意の3部分か
らゲルを切り取り同様に処理したところ、ケン化
度のバラツキは前者の場合75.0,75.3及び75.3モ
ル%であり、後者の場合76.4,76.5及び76.7モル
%であつて、実質的に均一であり、ケン化度の分
子間分布は少かつた。このときのメタノール量
(az+m)/anは2.1、水酸化ナトリウムはPVAc
に対し2.0ミリ当量であつた。Example 4 In order to obtain PVA with a degree of saponification of 75.0 mol%, 65.7 parts of PVAc with an average degree of polymerization of 300 was dissolved in 37.3 parts of methanol with a water content of 0.06% by weight, and the mixture was kept at a temperature of 40°C and dissolved in 5% by weight of water. sodium oxide methanol solution
1.22 parts were added, stirred for 5 minutes, and left to stand. Gelation occurred 20 minutes after addition of sodium hydroxide, but at 60 minutes and 120 minutes after gelation.
When the gels were treated in the same manner as in Example 1 after a few minutes had elapsed, the degree of saponification was 75.2.
and 76.5 mol%. At this time, when the gel was cut out from three arbitrary parts of the gel and treated in the same manner for each of the above points, the dispersion in the degree of saponification was 75.0, 75.3, and 75.3 mol% in the former case, and 76.4, 76.5 in the latter case. and 76.7 mol%, which was substantially uniform, and the intermolecular distribution of the degree of saponification was small. At this time, the amount of methanol (az+m)/an is 2.1, and the amount of sodium hydroxide is PVAc.
The amount was 2.0 milliequivalent.
比較のため、同じPVAc65.7部を含水率0.06%
のメタノール25.2部に溶解し、40℃で5重量%水
酸化ナトリウムメタノール溶液2.44部を加え同様
に処理したところ、水酸化ナトリウム添加後19分
後にゲル化が起こり、ゲル化後60分時点と120分
時点において、そのゲルの任意の部分からゲルを
切り取り同様に処理したところ、ケン化度は前者
の場合72.3,75.1及び78.0モル%、後者の場合
73.4,76.6及び78.9モル%であつてケン化度の進
行はそれほど認められなかつたものの、それぞれ
の時点におけるケン化度の分子間分布は実施例の
ものに比べてかなり広いものであつた。この時の
メタノール量(an+m)/anは1.5、水酸化ナト
リウムはPVAc対し4.0ミリ当量であつた。 For comparison, the same 65.7 parts of PVAc with a moisture content of 0.06%
When dissolved in 25.2 parts of methanol and treated in the same manner with 2.44 parts of 5% by weight sodium hydroxide methanol solution at 40°C, gelation occurred 19 minutes after the addition of sodium hydroxide, and 60 minutes and 120 minutes after gelation. When the gel was cut out from any part of the gel at the time point and treated in the same manner, the degree of saponification was 72.3, 75.1 and 78.0 mol% in the former case, and 78.0 mol% in the latter case.
73.4, 76.6, and 78.9 mol%, and although the degree of saponification did not progress much, the intermolecular distribution of the degree of saponification at each time point was considerably broader than that of the example. At this time, the amount of methanol (an+m)/an was 1.5, and the amount of sodium hydroxide was 4.0 milliequivalent to PVAc.
実施例 5
ケン化度60モル%のPVAを得ることを目的と
して平均重合度120のPVAc65.7部を含水率0.7重
量%のメタノール43.3部に溶解し、温度40℃に保
つて5重量%水酸化ナトリウムメタノール溶液
4.29部を添加し、5分間撹拌しそのまま放置し
た。水酸化ナトリウム添加後15分経過したのちゲ
ル化が起こつたが、ゲル化後60分経過した時点と
120分経過した時点において、ゲルを実施例1と
同様の方法で処理したのち、そのケン化度を測定
したところ、それぞれ60.0モル%及び60.1モル%
でありケン化度の進行は認められなかつた。ま
た、120分経過時点のゲルを常圧下105℃で60分間
乾燥したところ、揮発分は2.5%であつた。さら
に、この乾燥PVAを180℃で溶融したところ、溶
融粘度は33000センチポイズであり、溶融物は淡
黄色のわずかな着色が認められた程度であつた。
このときのメタノール量(an+m)/anは3.2、
水酸化ナトリウムはPVACに対し7ミリ当量であ
つた。Example 5 In order to obtain PVA with a saponification degree of 60 mol%, 65.7 parts of PVAc with an average degree of polymerization of 120 was dissolved in 43.3 parts of methanol with a water content of 0.7% by weight, and the mixture was kept at a temperature of 40°C and dissolved in 5% by weight water. sodium oxide methanol solution
4.29 parts were added, stirred for 5 minutes, and left to stand. Gelation occurred 15 minutes after addition of sodium hydroxide, but 60 minutes after gelation
After 120 minutes, the gel was treated in the same manner as in Example 1, and its saponification degree was measured to be 60.0 mol% and 60.1 mol%, respectively.
Therefore, no progress in the degree of saponification was observed. Furthermore, when the gel after 120 minutes was dried at 105° C. under normal pressure for 60 minutes, the volatile content was 2.5%. Furthermore, when this dried PVA was melted at 180°C, the melt viscosity was 33,000 centipoise, and the melt was only slightly colored pale yellow.
The amount of methanol (an+m)/an at this time is 3.2,
Sodium hydroxide was 7 meq to PVAC.
比較のため、同一のPVAc65.7部を含水率1.1重
量%のメタノール40.4部に溶解し、試行錯誤によ
り再現性よくケン化度60モル%のPVAが得られ
る条件を求めたところ、温度40℃のとき5重量%
の水酸化ナトリウムメタノール溶液の量は7.35
部、すなわちPVAcに対して12ミリ当量の水酸化
ナトリウムが必要であつた。このようにして得ら
れたケン化度60.3モル%のゲルを同様に乾燥した
ところ、揮発分は4.3%であつた。さらに、この
乾燥PVAを180℃で溶融したところ、溶融粘度は
31000センチポイズであつたが溶融物は茶色に着
色しており、PVAの分解臭が著しかつた。この
ときのメタノール量(an+m)/anは同様に3.2
であつた。 For comparison, 65.7 parts of the same PVAc was dissolved in 40.4 parts of methanol with a water content of 1.1% by weight, and through trial and error we determined the conditions under which PVA with a degree of saponification of 60 mol% could be obtained with good reproducibility. 5% by weight when
The amount of sodium hydroxide methanol solution is 7.35
12 milliequivalents of sodium hydroxide per part of PVAc was required. When the thus obtained gel with a degree of saponification of 60.3 mol% was similarly dried, the volatile content was 4.3%. Furthermore, when this dried PVA was melted at 180℃, the melt viscosity was
Although the temperature was 31,000 centipoise, the molten material was colored brown and had a strong PVA decomposition odor. The amount of methanol (an+m)/an at this time is also 3.2
It was hot.
第1図は平均重合度120のPVAcのメタノール
溶液におけるPVAc濃度とケン化度の関係を示す
ものである。第2図は平均重合度120のPVAcを
含水率の異なるメタノールに(an+m)/an=
3.0になるよう溶解し、温度40℃で水酸化ナトリ
ウムをPVAcに対し5ミリ当量添加してケン化し
た場合のケン化度の経時変化を示すものである。
第3図は平均重合度120のPVAcを含水率0.5重量
%のメタノールに(an+m)/anを変えて溶解
し、温度40℃で水酸化ナトリウムをPVAcに対し
5ミリ当量添加してケン化した場合のケン化度の
経時変化を示すものである。
Figure 1 shows the relationship between the PVAc concentration and the degree of saponification in a methanol solution of PVAc with an average degree of polymerization of 120. Figure 2 shows PVAc with an average degree of polymerization of 120 in methanol with different moisture contents (an+m)/an=
This figure shows the change over time in the degree of saponification when PVAc was dissolved at a temperature of 3.0 and saponified by adding 5 milli equivalents of sodium hydroxide to PVAc at a temperature of 40°C.
Figure 3 shows that PVAc with an average degree of polymerization of 120 was dissolved in methanol with a moisture content of 0.5% by weight while changing the ratio of (an+m)/an, and the mixture was saponified by adding 5 milliquivalents of sodium hydroxide to PVAc at a temperature of 40°C. This figure shows the change over time in the degree of saponification.
Claims (1)
触媒を添加してケン化し、ケン化度80モル%以下
のポリビニルアルコールを製造するに際し、メタ
ノールの含水率を0.05〜0.8重量%に保ち、該メ
タノールの量を所定ケン化度のポリビニルアルコ
ールを得るに必要な化学量論的量の2倍重量ない
し3.5倍重量になるように調節することによつて
ケン化度を制御することを特徴とするポリ酢酸ビ
ニルのケン化方法。1. When saponifying a methanol solution of polyvinyl acetate by adding an alkali catalyst to produce polyvinyl alcohol with a degree of saponification of 80 mol% or less, the water content of methanol is maintained at 0.05 to 0.8% by weight, and the amount of methanol is The degree of saponification of polyvinyl acetate is controlled by controlling the degree of saponification so that the weight is 2 to 3.5 times the stoichiometric amount required to obtain polyvinyl alcohol with a predetermined degree of saponification. Saponification method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2633577A JPS53110695A (en) | 1977-03-10 | 1977-03-10 | Saponification of polyvinyl acetate |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2633577A JPS53110695A (en) | 1977-03-10 | 1977-03-10 | Saponification of polyvinyl acetate |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS53110695A JPS53110695A (en) | 1978-09-27 |
JPS6141923B2 true JPS6141923B2 (en) | 1986-09-18 |
Family
ID=12190554
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2633577A Granted JPS53110695A (en) | 1977-03-10 | 1977-03-10 | Saponification of polyvinyl acetate |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS53110695A (en) |
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KR100419848B1 (en) * | 2001-12-04 | 2004-02-25 | 동양제철화학 주식회사 | Process for preparing polyvinyl alcohol microfibril |
KR100487024B1 (en) * | 2002-11-27 | 2005-05-03 | 학교법인 영남학원 | Cross-linked polyvinyl alcohol adhesive having various stereoregularities and manufacturing method thereof |
KR101024173B1 (en) | 2008-05-20 | 2011-03-22 | 영남대학교 산학협력단 | Polyvinylalcohol microfibrillar fiber and preparation method thereof |
KR101295647B1 (en) * | 2011-06-24 | 2013-08-12 | 에스케이씨 주식회사 | Method for preparing polyvinyl alcohol resin of high purity |
WO2020203660A1 (en) * | 2019-03-29 | 2020-10-08 | 三菱ケミカル株式会社 | Poly(vinyl alcohol)-based resin, method for producing poly(vinyl alcohol)-based resin, dispersant, and dispersant for suspension polymerization |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5187542A (en) * | 1975-01-31 | 1976-07-31 | Unitika Ltd | HORIBINIRUARUKOORUKEIHOTSUTOMERUTOGATASETSUCHAKUZAINO SEIZOHOHO |
JPS5187593A (en) * | 1975-01-31 | 1976-07-31 | Unitika Ltd | Horisakusanbiniruno kenkahoho |
-
1977
- 1977-03-10 JP JP2633577A patent/JPS53110695A/en active Granted
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5187542A (en) * | 1975-01-31 | 1976-07-31 | Unitika Ltd | HORIBINIRUARUKOORUKEIHOTSUTOMERUTOGATASETSUCHAKUZAINO SEIZOHOHO |
JPS5187593A (en) * | 1975-01-31 | 1976-07-31 | Unitika Ltd | Horisakusanbiniruno kenkahoho |
Also Published As
Publication number | Publication date |
---|---|
JPS53110695A (en) | 1978-09-27 |
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