JP2009051932A - Method for producing vinyl chloride polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a vinyl chloride polymer having excellent thermal stability and color in high productivity at a low cost. <P>SOLUTION: The method for producing a vinyl chloride polymer comprises the polymerization of a vinyl chloride-based monomer composed of vinyl chloride monomer singly or a mixture of vinyl chloride monomer and a monomer copolymerizable therewith in an aqueous medium in the presence of an oil-solution polymerization initiator. A part of the charging amounts of (A) the vinyl chloride-based monomer and (B) the oil-soluble initiator is charged and, thereafter, the remaining parts of the charging amounts of the components are added and mixed to the system. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は塩化ビニル系重合体の製造方法に関する。更に詳しくは、高生産性かつ低コストで高品質の塩化ビニル系重合体を製造する方法に関する。   The present invention relates to a method for producing a vinyl chloride polymer. More specifically, the present invention relates to a method for producing a high-quality vinyl chloride polymer with high productivity and low cost.

一般に、塩化ビニル系重合体は、水性媒体中、塩化ビニルなどの単量体（以下、塩化ビニル系単量体を塩化ビニルと略記することがある）を分散させ、油溶性開始剤を用いて重合を行う懸濁重合により広く行われてきた。   Generally, a vinyl chloride polymer is prepared by dispersing a monomer such as vinyl chloride (hereinafter, vinyl chloride monomer may be abbreviated as vinyl chloride) in an aqueous medium and using an oil-soluble initiator. It has been widely performed by suspension polymerization in which polymerization is performed.

近年、生産性の向上が図られているが、中でも重合開始剤の使用効率を向上させること
が注目されてきている。 In recent years, productivity has been improved, and in particular, attention has been focused on improving the use efficiency of the polymerization initiator.

重合で使用した開始剤のうち有効に作用しなかった開始剤は一般に重合体中に残存し、製品の熱安定性や色調を損なう怖れがあるためである。   This is because initiators that did not act effectively among the initiators used in the polymerization generally remain in the polymer, and there is a fear of impairing the thermal stability and color tone of the product.

この解決策として、たとえば活性の高い触媒、すなわち、触媒分解速度の半減期の短い触媒と活性の低い触媒、すなわち、触媒分解速度の半減期の長い触媒を組合せ、より少ない触媒量でしかも重合速度を均一にし重合末期の発熱を防止する方法が開示されている（特許文献１又は２）
しかし、これらの方法においても重合反応熱の均一化は必ずしも充分ではなく、また重合時間を短縮するためには使用する開始剤の総量が多くなり、高コストで、かつ得られる塩化ビニル系重合体の熱安定性や色調が劣るという問題点を解決することは困難であった。
一方で、目的は異なるが、油溶性開始剤を分割して仕込む方法が開示されている（特許文献３）、しかし、単純に油溶性開始剤を分割仕込みをしても、油滴にうまく分散されない可能性が高く追加時期に制限があるという問題があった。
特公昭４６−１４６７０号公報 特開昭５６−１４９４０７号公報 特開平４−１１６０７号公報 As a solution to this, for example, a highly active catalyst, that is, a catalyst having a short half-life of the catalytic cracking rate is combined with a catalyst having a low activity, that is, a catalyst having a long half-life of the catalytic cracking rate. A method for making the temperature uniform and preventing heat generation at the end of polymerization is disclosed (Patent Document 1 or 2).
However, even in these methods, the homogenization of the polymerization reaction heat is not always sufficient, and in order to shorten the polymerization time, the total amount of the initiator used increases, and the resulting vinyl chloride polymer is high in cost. It was difficult to solve the problem of poor heat stability and color tone.
On the other hand, although the purpose is different, a method is disclosed in which the oil-soluble initiator is divided and charged (Patent Document 3). However, even if the oil-soluble initiator is simply divided and charged, the oil-soluble initiator is well dispersed in the oil droplets. There was a problem that there was a possibility that it was not possible and there was a limit to the timing of addition.
Japanese Patent Publication No.46-14670 JP-A-56-149407 JP-A-4-11607

本発明の課題は、水性媒体中で塩化ビニル系重合体を製造する際の、上記のような油溶性重合開始剤の効率に関する問題点を解決し、高生産性かつ低コストで、熱安定性や色調に優れた塩化ビニル系重合体を製造する方法を提供することである。   The object of the present invention is to solve the above-mentioned problems related to the efficiency of the oil-soluble polymerization initiator when producing a vinyl chloride polymer in an aqueous medium, and to achieve high productivity, low cost, and thermal stability. And a method for producing a vinyl chloride polymer excellent in color tone.

すなわち本発明は、塩化ビニル単量体単独、又は、塩化ビニル単量体及びこれと共重合可能な単量体の混合物からなる塩化ビニル系単量体を、油溶性開始剤の存在下、水性媒体中で重合する方法であって、最初に（Ａ）塩化ビニル系単量体及び（Ｂ）油溶性開始剤のそれぞれの仕込み量の一部を仕込み、その後、（Ａ）（Ｂ）それぞれの仕込み量の残量を混合して追加することを特徴とする塩化ビニル系重合体の製造方法である。   That is, the present invention provides a vinyl chloride monomer comprising a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a monomer copolymerizable therewith in the presence of an oil-soluble initiator. It is a method of polymerizing in a medium. First, a part of the charged amount of each of (A) vinyl chloride monomer and (B) oil-soluble initiator is charged, and then each of (A) and (B) is charged. It is a manufacturing method of a vinyl chloride polymer characterized by mixing and adding the remaining amount of charge.

上記において、最初に仕込む（Ａ）塩化ビニル系単量体及び（Ｂ）油溶性開始剤のそれぞれの仕込み量の一部の量は、（Ａ）が仕込み量の２０重量％〜８０重量％、（Ｂ）が３０重量％〜９０重量％であるのが好ましい。前記（Ｂ）油溶性開始剤は、１０時間半減期温度が３０〜６５℃のものを少なくとも１種使用するのが好ましい。   In the above, (A) vinyl chloride monomer and (B) oil-soluble initiator, which are initially charged, are partially charged in such a manner that (A) is 20 wt% to 80 wt% of the charged amount, It is preferable that (B) is 30% by weight to 90% by weight. The (B) oil-soluble initiator is preferably at least one having a 10-hour half-life temperature of 30 to 65 ° C.

本発明によれば、油溶性開始剤を塩化ビニル単量体とともに連続的に重合系内に追加することで重合時間を短縮することができる。また重合反応熱の発生を重合時間全体にわたって均一化することで、重合反応機の除熱能力を余すことなく活用することが可能となり、さらに油溶性開始剤の使用量を減らすことも可能となる。   According to the present invention, the polymerization time can be shortened by continuously adding the oil-soluble initiator together with the vinyl chloride monomer into the polymerization system. In addition, by making the generation of polymerization reaction heat uniform over the entire polymerization time, it becomes possible to make full use of the heat removal capability of the polymerization reactor, and it is also possible to reduce the amount of oil-soluble initiator used. .

本発明の塩化ビニル系重合体を製造する方法において、重合反応機は水性媒体中での塩化ビニル系重合体の製造に使用される一般的なものでよい。すなわち、攪拌機、内部ジャケット、外部ジャケット、バッフル、主副原料投入口などを備えた耐圧容器でよく、重合中、重合反応熱を除去するためのリフラックスコンデンサー（還流凝縮器）を備えたものであってもよい。また、攪拌翼の形態はパドル型、ブルマージン型、ファウドラー型、タービン型など、塩化ビニル系重合体の製造に使用される一般的なものでよい。   In the method for producing a vinyl chloride polymer of the present invention, the polymerization reactor may be a general one used for producing a vinyl chloride polymer in an aqueous medium. That is, it may be a pressure vessel equipped with a stirrer, an inner jacket, an outer jacket, a baffle, a main auxiliary material input port, etc., and it is equipped with a reflux condenser (reflux condenser) for removing polymerization reaction heat during polymerization. There may be. The shape of the stirring blade may be a general one used for the production of a vinyl chloride polymer, such as a paddle type, a bull margin type, a fiddler type, and a turbine type.

本発明は、塩化ビニル単量体単独、又は、塩化ビニル単量体及びこれと共重合可能な単量体の混合物からなる塩化ビニル系単量体を油溶性開始剤の存在下、水性媒体中で重合する方法であるが、塩化ビニル単量体と共重合可能な単量体としては、例えば、酢酸ビニル等のアルキルビニルエステル類、セチルビニルエーテルなどのアルキルビニルエーテル類、エチレン、プロピレン等のα−オレフィン類、アクリル酸メチル、メタクリル酸メチル等の（メタ）アクリル酸アルキルエステル類、塩化ビニリデン等のビニリデン化合物等が挙げられる。   The present invention relates to a vinyl chloride monomer alone or a vinyl chloride monomer comprising a mixture of a vinyl chloride monomer and a monomer copolymerizable therewith in an aqueous medium in the presence of an oil-soluble initiator. Examples of monomers that can be copolymerized with vinyl chloride monomer include alkyl vinyl esters such as vinyl acetate, alkyl vinyl ethers such as cetyl vinyl ether, and α- such as ethylene and propylene. Examples include olefins, alkyl (meth) acrylates such as methyl acrylate and methyl methacrylate, and vinylidene compounds such as vinylidene chloride.

次に、本発明における油溶性開始剤は本発明の目的が達成できるものであれば特に制限はないが、これらの開始剤のうち１０時間半減期温度が３０〜６５℃のものを少なくとも１種使用するのが好ましい。重合開始剤の例としては、アセチルシクロヘキシルスルフォニルパーオキサイド、２，４，４トリメチルペンチル−２−パーオキシネオデカノエート、ジ−２−エチルヘキシルパーオキシジカーボネート、ジ（２−エトキシエチル）パーオキシジカーボネート、ｔ−ブチルパーオキシピバレート、３，５，５−トリメチルヘキサノイルパーオキサイド等の有機過酸化物系開始剤、アゾビスイソブチロニトリル、アゾビス−２，４，−ジメチルバレロニトリル等のアゾ系開始剤等が挙げられる。
これらの油溶性開始剤は、安全のため一般に有機溶剤で希釈されているが、本発明ではこれをそのまま用いることができ、懸濁安定剤や乳化剤等を用いて分散液や乳化液として用いる必要はない。 Next, the oil-soluble initiator in the present invention is not particularly limited as long as the object of the present invention can be achieved, but at least one of these initiators having a 10-hour half-life temperature of 30 to 65 ° C. It is preferred to use. Examples of polymerization initiators include acetylcyclohexyl sulfonyl peroxide, 2,4,4 trimethylpentyl-2-peroxyneodecanoate, di-2-ethylhexyl peroxydicarbonate, di (2-ethoxyethyl) peroxy Organic peroxide initiators such as dicarbonate, t-butylperoxypivalate, 3,5,5-trimethylhexanoyl peroxide, azobisisobutyronitrile, azobis-2,4, -dimethylvaleronitrile, etc. And azo initiators.
These oil-soluble initiators are generally diluted with an organic solvent for safety, but in the present invention, they can be used as they are and need to be used as dispersions or emulsions using suspension stabilizers or emulsifiers. There is no.

本発明では、最初に（Ａ）塩化ビニル系単量体及び（Ｂ）油溶性開始剤のそれぞれの仕込み量の一部を仕込み、その後、（Ａ）（Ｂ）それぞれの仕込み量の残量を混合して追加することを特徴とする塩化ビニル系重合体の製造方法である。
上記の混合して追加するとは、事前に別のタンクなどで混合してから追加するか、または追加時に導管内で同時に混合されるようにする等の方法を用いれば良く、（Ａ）と（Ｂ）とが充分に馴染むようにできるのであれば、手段に特に制限はない。また、追加の方法は、連続的追加が好ましいが、必ずしも間断なく追加することのみを意味するのではなく、間欠的な追加でも良い。このとき、追加する速度や、間欠的追加の場合における追加回数等は任意に設定することができる。最初に仕込む量は、（Ａ）が、仕込み量の３０重量％〜９０重量％ （Ｂ）が、仕込み量の２０重量％〜８０重量％であるのが好ましい。
本発明によれば、追加前に塩化ビニル単量体と混合し追加するため、追加時期を任意に設定することができる。 In the present invention, first, a part of each charged amount of (A) vinyl chloride monomer and (B) oil-soluble initiator is charged, and then the remaining amount of each charged amount of (A) and (B) is determined. It is a method for producing a vinyl chloride polymer, which is added by mixing.
The above mixing and adding may be performed by mixing in a separate tank or the like in advance, or by using a method such as mixing at the same time in the conduit at the time of addition, and (A) and ( There are no particular restrictions on the means as long as B) can be sufficiently adapted to. Further, the addition method is preferably continuous addition, but it does not necessarily mean that the addition is performed without interruption, but may be intermittent addition. At this time, the speed to be added and the number of times of addition in the case of intermittent addition can be arbitrarily set. As for the amount initially charged, (A) is preferably 30% to 90% by weight of the charged amount. (B) is preferably 20% to 80% by weight of the charged amount.
According to the present invention, the addition time is arbitrarily set since it is added with the vinyl chloride monomer before the addition.

また、仕込み量の残量を連続的に追加するに際し、（Ｂ）の追加は（Ａ）の追加が行われるときに合わせて行うことが好ましい。つまり、両者の追加の開始を同時にするか、もしくは塩化ビニル単量体の連続的追加を先に開始するのが好ましい。油溶性開始剤の連続的追加を塩化ビニル単量体の連続的追加より先に開始すると、先に追加される油溶性開始剤が既に存在する塩化ビニル系単量体の油滴にうまく分散されない為、本発明の効果が十分に発揮されない可能性がある。さらに、塩化ビニル単量体の連続的追加を開始した後、油溶性開始剤の連続的追加を開始するまでの時間差は任意に設定することができる。
次に、油溶性開始剤の連続的追加の終了は塩化ビニル単量体の連続的追加の終了より先になるのが好ましい。塩化ビニル単量体の連続的追加を油溶性開始剤の連続的追加より先に終了すると、後で追加される油溶性開始剤が既に存在する塩化ビニル系単量体の油滴にうまく分散されず、本発明の効果が十分に発揮されない可能性がある。 In addition, when continuously adding the remaining amount of charge, it is preferable to add (B) when (A) is added. That is, it is preferable to start addition of both at the same time or to start continuous addition of the vinyl chloride monomer first. If the continuous addition of the oil soluble initiator is started before the continuous addition of the vinyl chloride monomer, the previously added oil soluble initiator is not well dispersed in the existing vinyl chloride monomer droplets. For this reason, the effect of the present invention may not be sufficiently exhibited. Further, the time difference from the start of continuous addition of the vinyl chloride monomer to the start of continuous addition of the oil-soluble initiator can be arbitrarily set.
Next, the end of continuous addition of the oil soluble initiator is preferably preceded by the end of continuous addition of the vinyl chloride monomer. If the continuous addition of the vinyl chloride monomer is completed before the continuous addition of the oil-soluble initiator, the oil-soluble initiator added later is well dispersed in the vinyl chloride monomer oil droplets already present. Therefore, the effect of the present invention may not be sufficiently exhibited.

本発明で塩化ビニル系単量体の重合に用いる水溶性もしくは水分散性の高分子懸濁分散安定剤は、部分ケン化ポリ酢酸ビニル、メチルセルロース、ヒドロキシプロポキシメチルセルロース、カルボキシメチルセルロース、ポリビニルピロリドン、ポリアクリル酸、酢酸ビニルーマレイン酸共重合体、スチレンーマレイン酸共重合体、ゼラチン、デンプン、ポリエチレンオキサイド、オキシエチレン−オキシプロピレンブロック共重合体等が挙げられ、これらは単独または２種以上組み合わせて用いることができる。   The water-soluble or water-dispersible polymer suspension stabilizer used for the polymerization of the vinyl chloride monomer in the present invention is partially saponified polyvinyl acetate, methylcellulose, hydroxypropoxymethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyacrylic. Examples include acids, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, gelatin, starch, polyethylene oxide, oxyethylene-oxypropylene block copolymers, and these are used alone or in combination of two or more. be able to.

さらに、従来塩化ビニル系単量体の重合または共重合に使用される重合度調節剤、連鎖移動剤、ｐＨ調節剤、ゲル化性改良剤、帯電防止剤、乳化剤、安定剤、スケール防止剤等やこれらの仕込み方法も本発明の目的が達成できるものや方法であれば特に制限はない。   In addition, polymerization degree regulators, chain transfer agents, pH regulators, gelling improvers, antistatic agents, emulsifiers, stabilizers, scale inhibitors, etc., conventionally used for polymerization or copolymerization of vinyl chloride monomers. There is no particular limitation on these preparation methods as long as the object of the present invention can be achieved.

以下に、本発明の具体的実施例について詳細に説明するが、本発明は以下の実施例によって限定されるものではない。なお、以下の実施例では特に断りのない限り「部」は重量部、「％」は重量％を表す。また本実施例の水は全てイオン交換水を用いた。   Specific examples of the present invention will be described in detail below, but the present invention is not limited to the following examples. In the following examples, “parts” represents parts by weight and “%” represents percent by weight unless otherwise specified. Moreover, all the water of the present Example used ion exchange water.

（評価方法の説明）
（１）プレス板色調
塩化ビニル系重合体１００部に錫系安定剤２．５部を添加し十分撹拌混合した後、この混合物を表面温度１６０℃の８インチ二本ロールで５分間混練した。得られたロールシートを適当な大きさに裁断し、１６５℃に調節したプレスで１５分間、圧力７ＭＰａにて厚さ５ｍｍの板に成型した。得られた成型板を用いて、塩化ビニル系重合体の色調を評価した。なお、日本電色工業株式会社製測色色差計ＺＥ２０００を使用してｂ値を測定し、評価をした。ｂ値が小さいほど色調は良好である。
（２）熱安定性
上記（１）で得られたロールシートを５ｃｍ×３ｃｍに裁断し、この裁断シートを複数枚同時に１９０℃のギヤオーブン中で加熱し、加熱開始から変化を観察した。加熱開始から、シートの一部分もしくは全部分が黒化する時点までの時間を観察した。黒化までの時間が長いほど、熱安定性が良好である。 (Explanation of evaluation method)
(1) Color tone of press plate After adding 2.5 parts of a tin stabilizer to 100 parts of a vinyl chloride polymer and sufficiently stirring and mixing, the mixture was kneaded for 5 minutes with an 8-inch double roll having a surface temperature of 160 ° C. The obtained roll sheet was cut into a suitable size and molded into a 5 mm thick plate at a pressure of 7 MPa for 15 minutes with a press adjusted to 165 ° C. Using the obtained molded plate, the color tone of the vinyl chloride polymer was evaluated. In addition, b value was measured and evaluated using the color measurement color difference meter ZE2000 by Nippon Denshoku Industries Co., Ltd. The smaller the b value, the better the color tone.
(2) Thermal stability The roll sheet obtained in the above (1) was cut into 5 cm × 3 cm, and a plurality of the cut sheets were simultaneously heated in a gear oven at 190 ° C., and changes were observed from the start of heating. The time from the start of heating to the time when part or all of the sheet blackened was observed. The longer the time until blackening, the better the thermal stability.

（実施例１）
撹拌機、還流凝縮器を付設した内容積２０００Ｌのステンレス製重合器内に、平均重合度が２０００でケン化度７９％の部分ケン化ポリ酢酸ビニルを３％水溶液で０．０５０部（全単量体の合計１００部に対して、以下同じ）、及び平均分子量４５０万のポリエチレンオキサイドを０．５％水溶液で０．０１０部、油溶性開始剤としてｔｅｒｔ−ブチルパーオキシネオデカノエート０．０４０部（油溶性開始剤仕込量の５０重量％）を投入した後、重合器を密閉し、器内を真空ポンプで脱気した。次いで、この重合器内に、脱気後７０℃に温度調節した温水１００部を仕込み始めた後、塩化ビニル単量体８０部（単量体仕込量の８０重量％）を仕込み始め、ほぼ同時に所定量を仕込み終えた。撹拌機は塩化ビニル単量体を仕込み始めると同時に稼働した。仕込み終了後、ジャケット及び還流凝縮器による温度調節を実施し、重合中内温を６３℃に維持した。 (Example 1)
In a stainless steel polymerization vessel having an internal volume of 2000 L and equipped with a stirrer and a reflux condenser, 0.050 part of a partially saponified polyvinyl acetate having an average polymerization degree of 2000 and a saponification degree of 79% in 3% aqueous solution The same applies hereinafter with respect to a total of 100 parts of the polymer), 0.010 parts of polyethylene oxide having an average molecular weight of 4.5 million in a 0.5% aqueous solution, and tert-butyl peroxyneodecanoate as an oil-soluble initiator. After adding 040 parts (50 wt% of the oil-soluble initiator charge amount), the polymerization vessel was sealed and the inside of the vessel was deaerated with a vacuum pump. Next, after deaeration, 100 parts of warm water adjusted to 70 ° C. was started in this polymerization vessel, and then 80 parts of vinyl chloride monomer (80% by weight of the monomer charge) was started, almost simultaneously. The prescribed amount has been charged. The stirrer was started as soon as the vinyl chloride monomer was charged. After completion of the charging, the temperature was adjusted with a jacket and a reflux condenser, and the internal temperature was maintained at 63 ° C. during the polymerization.

重合開始後２０分後に、塩化ビニル単量体とｔｅｒｔ−ブチルパーオキシネオデカノエートを重合機内に入る前に導管内で混合するようにしてそれぞれ等速で連続追加を開始し、１２０分までに塩化ビニル単量体２０部（単量体仕込量の２０重量％）、ｔｅｒｔ−ブチルパーオキシネオデカノエート０．０４０部（油溶性開始剤仕込量の５０重量％）をそれぞれ等速で全量連続追加した。   Twenty minutes after the start of the polymerization, the vinyl chloride monomer and tert-butylperoxyneodecanoate were mixed in the conduit before entering the polymerization machine, and each continuous addition was started at a constant speed until 120 minutes. 20 parts by weight of vinyl chloride monomer (20% by weight of the monomer charge) and 0.040 parts of tert-butylperoxyneodecanoate (50% by weight of the oil-soluble initiator charge) at a constant speed, respectively. The whole amount was added continuously.

重合開始後１９０分後、重合機内圧が定常圧より０．１ＭＰａ低下した時点で重合を停止し、未反応単量体を回収して重合を終了した。得られたスラリーを脱水、乾燥したところ、転化率８０％で塩化ビニル重合体を得た。   190 minutes after the start of the polymerization, the polymerization was stopped when the internal pressure of the polymerization machine decreased by 0.1 MPa from the steady pressure, and the unreacted monomer was recovered to complete the polymerization. When the obtained slurry was dehydrated and dried, a vinyl chloride polymer was obtained at a conversion rate of 80%.

（実施例２）
重合仕込み時の油溶性開始剤の仕込み量を、ｔｅｒｔ−ブチルパーオキシネオデカノエート０．０３６部（油溶性開始剤仕込量の５０重量％）にし、また、油溶性開始剤の連続追加仕込み量をｔｅｒｔ−ブチルパーオキシネオデカノエート０．０３６部（油溶性開始剤仕込量の５０重量％）とした以外は実施例１の仕込み、及び重合条件にて重合したところ、２１０分で重合機内圧が０．１ＭＰａ低下し、未反応単量体を回収して重合を終了した。得られたスラリーを脱水、乾燥して塩化ビニル重合体を得た。転化率は８０％であった。 (Example 2)
The amount of the oil-soluble initiator charged at the time of polymerization is 0.036 parts of tert-butylperoxyneodecanoate (50% by weight of the amount of the oil-soluble initiator), and the oil-soluble initiator is continuously added. Polymerization was carried out in the same manner as in Example 1 except that the amount was 0.036 parts of tert-butylperoxyneodecanoate (50% by weight of the oil-soluble initiator charge) and the polymerization conditions. The in-machine pressure decreased by 0.1 MPa, and the unreacted monomer was recovered to complete the polymerization. The obtained slurry was dehydrated and dried to obtain a vinyl chloride polymer. The conversion was 80%.

（比較例１）
塩化ビニル単量体１００部と油溶性開始剤ｔｅｒｔ−ブチルパーオキシネオデカノエート０．０３部及び３，５，５−トリメチルヘキサノイルパーオキシド０．０５部を重合仕込み時に仕込み、塩化ビニル単量体、及び油溶性開始剤の連続追加をすることなく重合した以外は、実施例１の仕込み、及び重合条件にて重合したところ、２１０分で重合機内圧が０．１ＭＰａ低下し、未反応単量体を回収して重合を終了した。得られたスラリーを脱水、乾燥して塩化ビニル重合体を得た。転化率は８０％であった。
得られた結果を表１に示した。 (Comparative Example 1)
100 parts of vinyl chloride monomer, 0.03 part of oil-soluble initiator tert-butylperoxyneodecanoate and 0.05 part of 3,5,5-trimethylhexanoyl peroxide were charged at the time of polymerization. Except for polymerization without continuous addition of a monomer and an oil-soluble initiator, polymerization was carried out under the same conditions as in Example 1 and under the polymerization conditions. The monomer was recovered to complete the polymerization. The obtained slurry was dehydrated and dried to obtain a vinyl chloride polymer. The conversion was 80%.
The obtained results are shown in Table 1.

Claims (3)

塩化ビニル単量体単独、又は、塩化ビニル単量体及びこれと共重合可能な単量体の混合物からなる塩化ビニル系単量体を、油溶性開始剤の存在下、水性媒体中で重合する方法であって、最初に（Ａ）塩化ビニル系単量体及び（Ｂ）油溶性開始剤のそれぞれの仕込み量の一部を仕込み、その後、（Ａ）（Ｂ）それぞれの仕込み量の残量を混合して追加することを特徴とする塩化ビニル系重合体の製造方法。   A vinyl chloride monomer consisting of a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a monomer copolymerizable therewith is polymerized in an aqueous medium in the presence of an oil-soluble initiator. First, a part of each charged amount of (A) vinyl chloride monomer and (B) oil-soluble initiator is charged first, and then (A) (B) the remaining amount of each charged amount A method for producing a vinyl chloride polymer, characterized by comprising mixing and adding. 最初に仕込む（Ａ）塩化ビニル系単量体及び（Ｂ）油溶性開始剤のそれぞれの仕込み量の一部の量は、（Ａ）が仕込み量の１０重量％〜８０重量％、（Ｂ）が３０重量％〜９０重量％である請求項１記載の塩化ビニル系重合体の製造方法。   First, (A) vinyl chloride monomer and (B) oil-soluble initiators are partially charged in amounts of 10% to 80% by weight of (A), (B) The method for producing a vinyl chloride polymer according to claim 1, wherein is 30 wt% to 90 wt%. （Ｂ）油溶性開始剤は、１０時間半減期温度が３０〜６５℃のものを少なくとも１種使用する請求項１又は２に記載の塩化ビニル系重合体の製造方法。   (B) The method for producing a vinyl chloride polymer according to claim 1 or 2, wherein at least one oil-soluble initiator having a 10-hour half-life temperature of 30 to 65 ° C is used.