JP3730790B2 - Method for producing vinyl chloride resin and resin composition thereof - Google Patents

Description

【０００１】
【発明の属する技術分野】
本発明は塩化ビニル系樹脂の製造方法及びその樹脂組成物に関するものであり、詳細には加工性及び熱的安定性に優れ且つ物性低下のない塩化ビニル系樹脂の製造方法及びその樹脂を用いた樹脂組成物に関する。
【０００２】
【従来の技術】
塩化ビニル系樹脂は安価で且つ品質バランスに優れているため、硬質分野、軟質分野等種々の広範な分野で利用されている熱可塑性樹脂であり、その用途として例えば硬質分野ではパイプや継手、窓枠、工業用透明板、フィルム等が、軟質分野では電線被覆、ラップフィルム、シート等がそれぞれ挙げられる。
【０００３】
材料としての塩化ビニル系樹脂は安価なことが必須である汎用樹脂であるが、性能面でも種々の特性が要求され、例えば前述の軟質用途分野における製品では高い体積固有抵抗値、良好な可塑剤吸収性、フィッシュアイの低減、等が挙げられる。
【０００４】
一方硬質用途分野においては、種々成形体に加工する際の加工性・熱的安定性、成形後の引張強度や衝撃強度等の基本物性、等が良好であることが求められる。これらの要求特性を改良するために様々な工夫がなされてきており、これまでに開示された技術にも数多く見ることができる。例えば特開平９−２７８９６４号公報には、耐衝撃性及び成形加工性向上の為に塩化ビニル系樹脂にメタクリル酸メチル・ブタジエン・スチレン共重合体または塩素化ポリエチレンを添加する方法、特開平１０−１５８４号公報には熱安定性や加工性等の向上の為に塩化ビニル系樹脂にカルシウム化合物、亜鉛化合物、エポキシ化植物油、β―ジケトン化合物及びエステル系化合物を添加する方法、特開平１０−１７７４４号公報には成形加工性改善の為に塩化ビニル系樹脂に塩素化ポリオレフィン及び／またはビニルエステル―エチレン共重合体を配合する方法、等が開示されている。
【０００５】
しかしながらこれらの方法ではいずれも各種強化剤や添加剤を配合しており、概して多種多量の強化剤・添加剤が必要となる。
【０００６】
【発明が解決しようとする課題】
本発明は前記従来技術に鑑みてなされたものであり、多種多量の強化剤・添加剤を配合することなく、加工性及び熱的安定性に優れ且つ物性低下のない塩化ビニル系樹脂の製造方法及びその樹脂を含有する組成物を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明者らは、前述の品質上の要求特性すなわち加工性及び熱的安定性に優れ且つ物性低下のない塩化ビニル系樹脂の製造方法及びその組成物について鋭意検討した結果、特定の分散剤を組み合わせて懸濁重合で製造される塩化ビニル系重合体を硬質用途に用いることによって、強化剤や添加剤の問題点を生じることなく前記要求特性に優れた塩化ビニル系樹脂組成物を得ることができることを見出し、本発明に到った。すなわち本発明は、塩化ビニル単量体または塩化ビニルと共重合可能な単量体と塩化ビニル単量体との混合物を水性媒体中で懸濁重合させるに際し、塩化ビニル単量体または塩化ビニルと共重合可能な単量体と塩化ビニル単量体との混合物（以下、単に塩化ビニル系単量体と略記する）１００重量部に対し、懸濁分散安定剤として（ａ）鹸化度が７０〜８５％、平均重合度が１５００〜２５００である部分鹸化ポリ塩化ビニル０．０３〜０．０８重量部、（ｂ）鹸化度が３３〜７０％、平均重合度が２００〜１０００である部分鹸化ポリ酢酸ビニル０．０１〜０．０５重量部、（ｃ）５重量％水溶液の粘度が５０〜５５００ｍＰａ・ｓであり、プロピレンオキサイド含量が５〜９５モル％である、エチレンオキサイドとプロピレンオキサイドとの共重合体０．００３〜０．０２重量部、（ｄ）平均分子量が４００〜５００万であるポリエチレンオキサイド０．００１〜０．０２重量部、を用いることを特徴とする塩化ビニル系樹脂の製造方法（請求項１）をその内容とする。
【０００８】
【発明の実施の形態】
以下、本発明について詳細に説明する。
【０００９】
本発明に用いられる塩化ビニル系重合体の製造にはこれら４種の分散剤を併用することが必須である。
（ａ）は塩化ビニル系重合体を製造する際、最も一般的に用いられる部分鹸化ポリ酢酸ビニル（以下ＰＶＡと略記）と言って良い。（ａ）の鹸化度は７０〜８５％である。鹸化度が７０％未満では界面活性が強くなりすぎると共に水に溶け難くなるため扱いが困難とり、また鹸化度が８５％を超えると界面活性不足により重合反応が安定に進行しにくい。（ａ）の量は、塩化ビニル系単量体１００重量部に対して０．０３〜０．０８重量部、好ましくは０．０４〜０．０６重量部である。この量が０．０３重量部未満では重合反応を安定的に進行させることができず、また０．０８重量部を超えると生成する樹脂表面の分散剤膜が厚くなりすぎて加工性に悪影響を及ぼす。さらにこの（ａ）の平均重合度は１５００〜２５００、好ましくは１８００〜２２００である。平均重合度が１５００未満では重合反応を安定的に進行させる為に使用量を増やすことが必要で、結果として樹脂表面分散剤膜の厚みが厚くなりすぎるし、平均重合度が２５００を超えると用いる量が少なくても樹脂表面分散剤膜の厚みが厚くなりすぎるので、いずれの場合も好ましくない。
（ｂ）は加工性改良の為に樹脂内部を高多孔質とするのに適したＰＶＡと言えるが、単独では重合反応を安定的に進行させることが非常に困難であり、（ａ）のようなＰＶＡ等を併用することが必要である。（ｂ）の鹸化度は３３〜７０％である。鹸化度が３３％未満では水に対する溶解性、あるいは膨潤性があまりにも低下しすぎて樹脂内部の多孔性を高める効果が発現し難くなる。また鹸化度が７０％を超えると単量体への溶解性が実質的になくなり、樹脂内部を多孔性にする効果が期待できない。（ｂ）の量は、塩化ビニル系単量体１００重量部に対して０．０１〜０．０５重量部、好ましくは０．０２〜０．０４重量部である。この量が０．０１重量部未満では樹脂内部の多孔性が十分にはならず、また０．０５重量部を超えると重合反応を安定的に進行させることが困難となる。さらにこの（ｂ）の平均重合度は２００〜１０００、好ましくは３００〜７００である。平均重合度が２００未満では単量体への溶解度があまりにも大きすぎて初期に生成する単量体油滴が不安定となり、重合反応が正常に進行できない。平均重合度が１０００を超えると逆に単量体への溶解度が低すぎて生成する樹脂内部の多孔度を高くできない。
【００１０】
（ｃ）のエチレンオキサイドとプロピレンオキサイドとの共重合体（以下、ＥＯ−ＰＯ共重合体と略記）は、ＰＶＡ並の高い界面活性と、ＰＶＡ等で覆われた単量体油滴どうしが衝突によって融着するのを抑制する効果（油滴保護力）の２種の特性を示す。（Ｃ）の５重量％水溶液粘度は５０〜５５００ｍＰａ・ｓであり、好ましくは２５００〜５５００ｍＰａ・ｓである。５重量％水溶液粘度が５０ｍＰａ・ｓ未満の場合及び５５００ｍＰａ・ｓを越える場合は、いずれも重合反応が安定的に進行せず、異常重合を起こす。（ｃ）の量は塩化ビニル系単量体１００重量部に対して０．００３〜０．０２重量部である。この量が０．００３重量部未満では重合反応が安定的に進行せず異常重合をおこし、０．０２重量部を越えると得られる樹脂の粒径が非常に小さくなる。さらに、この（ｃ）におけるプロピレンオキサイド（以下ＰＯと略記）含量は５〜９５モル％である。５モル％未満であると、ＰＶＡ並の高い界面活性を示すというＥＯ−ＰＯ共重合体の特性が発現しない。また９５モル％を越えると粘度が低下し、油滴保護力が発現しなくなって、異常重合を起こす。
【００１１】
（ｄ）の分散剤は他の分散剤とは異なり界面活性能力をほとんど有しない。また分子量、従って粘度が非常に高く著しい増粘効果を示すことが特徴であり、水／単量体油滴界面の水側に局在し、ＰＶＡ等で覆われた単量体油滴どうしが衝突によって融着するのを抑制する効果が非常に高い。また著しい高粘度の故に極く少量でこの融着抑制効果を示す。この作用によって他の分散剤の使用量を大幅に減らすことが可能となり、特にここで用いる（ａ）のような分散剤量を減らすことは表面の分散剤膜を薄くすることにつながり有益である。（ｄ）の量は、塩化ビニル系単量体１００重量部に対して０．００１〜０．０２重量部、好ましくは０．００３〜０．００８重量部である。この量が０．００１重量部未満ではこの分散剤特有の増粘効果が乏しく他の分散剤、特に（ａ）タイプの分散剤量を多く必要とする。また０．０１重量部を超えると重合安定性向上効果が飽和する上に、生成する樹脂の粒度分布が非常に広くなる。さらにこの（ｄ）の平均分子量は４００〜５００万である。平均分子量が４００万未満では前述のような十分な融着抑制効果を得るためにその使用量を増やしたり（ａ）のような分散剤を増やす必要が生じるため、結果として樹脂表面分散剤膜の厚みが厚くなる。平均分子量が５００万を超えると樹脂表面分散剤膜の厚みが厚くなりすぎるとともに水溶液粘度が著しく高くなるために扱い難くなるといった問題が生じる。
【００１２】
本発明に用いられる塩化ビニル系重合体を製造する際に使用する単量体は塩化ビニルを主成分とする単量体であり、具体的には、塩化ビニル単量体単独、又は塩化ビニルを７０重量％以上含有する、塩化ビニルと共重合可能な単量体と塩化ビニル単量体との混合物である。
【００１３】
塩化ビニルと共重合可能な単量体としては、例えば酢酸ビニル、プロピオン酸ビニル等のビニルエステル類、エチレン、プロピレン、イソブチルビニルエーテル等のα−オレフィン類、１−クロロプロピレン、２−クロロブチレン等のクロル化オレフィン類、（メタ）アクリル酸メチル等の（メタ）アクリル酸エステル類、無水マレイン酸、アクリロニトリル、スチレン、塩化ビニリデン等が挙げられ、これらは単独で用いることも、２種以上組み合わせて用いることも可能である。
【００１４】
本発明に用いられる塩化ビニル系重合体を製造する際における原料の仕込みは公知の技術を任意に用いることができる。例えば最も一般的な方法として、先に水を仕込んだ後単量体を仕込む方法、重合温度まで昇温する時間を短縮する目的で先に単量体を仕込んだ後温水を仕込む方法、さらに仕込み及び昇温時間を短縮する目的で単量体と温水を同時に仕込む方法等を用いることができる。
【００１５】
また重合反応熱の除去は、従来の方式、例えば外部あるいは内部ジャケットによる除熱、還流凝縮器による方法等を利用すれば良い。
【００１６】
さらに従来塩化ビニル系単量体の重合又は共重合に使用される重合開始剤、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方法も公知の技術をなんら支障なく任意に用いることができ、その使用量も従来公知の方法に従うことができる。
【００１７】
本発明においては、このようにして製造された塩化ビニル系樹脂に任意の安定剤及び滑剤等を配合することによって、加工性や熱安定性に優れ、かつ物性低下のない塩化ビニル系樹脂組成物を得ることができる。安定剤は錫系安定剤や鉛系安定剤等従来公知のものをなんら支障なく任意に用いることができ、その使用量も従来公知の方法に従うことができる。また滑剤についても脂肪酸エステル系滑剤やオレフィン系滑剤等、従来公知のものをなんら支障なく任意に用いることができその使用量も従来公知の方法に従うことができる。この樹脂組成物の用途については特に限定されないが、その樹脂品質から、特に硬質用途において好適に使用できる。
【００１８】
【実施例】
本発明をさらに具体的に説明するために、以下に実施例および比較例を示すが、これら実施例は本発明をなんら限定するものではない。なお、以下の実施例では特にことわりのない限り「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。得られた塩化ビニル系樹脂の特性値の測定及び組成物の加工性・熱的安定性・物性の評価は次の方法により実施した。
（１）平均粒子径、粒度分布
ＪＩＳ Ｋ−６７２１に準拠し、４２、６０、８０、１００、１２０、１４５、２００メッシュの篩を使用し、篩振とう器にて篩分けを行い、５０％通過径をもって平均粒子径（μｍ）とした。
（２）多孔度
AMINCO社製の水銀圧入式ポロシメーター（５−７１１８型）を用いて、絶対圧３１〜１０１１ｐｓｉ（ポア口径０．１７５〜５．６５μｍ）の間で塩化ビニル系樹脂に圧入される水銀の容量を測定し、塩化ビニル系樹脂１００ｇあたりの圧入水銀量（ｃｃ）を算出した。
（３）加工性
塩化ビニル系樹脂１００部に有機錫系安定剤０．５部、脂肪酸エステル系滑剤０．１部、ポリエチレン系滑剤０．２部を添加し十分撹拌混合した後、表面温度を１７０℃・１８０℃・１９０℃に調節した８インチロールに投入した。それぞれの温度で５分間混練して厚み約０．５ｍｍのロールシートを取り出し、シートの仕上がり状態を目視で確認して、加工性を以下の評価基準に従って○・△・×の三段階で評価した。
【００１９】
○…十分混練され均一なシートが得られる
△…やや混練不十分でシートにも不均一な部分が見られる
×…まったく混練不十分で、シートも至る所に穴が開いている
（４）熱的安定性
塩化ビニル系樹脂１００部に有機錫系安定剤０．５部、脂肪酸エステル系滑剤０．１部、ポリエチレン系滑剤０．２部を添加し十分撹拌混合した後、この混合物６０ｇ（平均重合度１３００タイプの塩化ビニル系樹脂を用いた組成物）または６２ｇ（平均重合度１０００タイプの塩化ビニル系樹脂を用いた組成物）を東洋精機社製のラボプラストミル試験機に投入し、ローターの回転数５０ｒｐｍ、チャンバー温度１８０℃の条件下で、塩化ビニル系樹脂組成物を投入してからトルクが立ち上がりを示すまでの時間を測定した。この時間が長いほど熱的安定性は高いと判断した。
（５）物性評価
塩化ビニル系樹脂１００部に有機錫系安定剤０．５部、脂肪酸エステル系滑剤０．１部、ポリエチレン系滑剤０．２部を添加し十分撹拌混合した後、表面温度を１９０℃に調節した８インチロールに投入した。それぞれの温度で５分間混練して厚み約０．５ｍｍのロールシートを取り出した。このシートを重ねて２００℃で６分間予熱をし、２分間４．９ＭＰａの面圧で熱プレスにより１ｍｍ厚の板を作製した。得られた板からＪＩＳ−２号形引張試験片を作製し、ＪＩＳ−Ｋ７１１３に準じて試験速度１０ｍｍ／ｍｉｎで試験を行い降伏点強度・１％モジュラス・破断強度・破断時伸びを測定した。なお１％モジュラスの「％」は基準長さに対する伸びの割合を表わす。
（実施例１及び３）
撹拌機を付設した内容積２０００Ｌのステンレス製重合器内に、鹸化度が７４％、平均重合度が２０００であるＰＶＡ（これをＰＶＡ１という）の３％水溶液７．３３ｋｇ、鹸化度が５６％、平均重合度が３００であるＰＶＡ（これをＰＶＡ２という）０．１６５ｋｇ、ＰＯ含量が５０モル％、５％水溶液の粘度が３０００ｍＰａ・ｓであるＥＯ−ＰＯ共重合体の２％水溶液２．７５ｋｇ、平均分子量が４５０万であるポリエチレンオキサイド（これをＰＥＯ１という）の０．５％水溶液４．４ｋｇ、及びジ−２−エチルヘキシルパーオキシジカーボネートを濃度７０％で溶解したイソパラフィン溶液０．３９３ｋｇを仕込んだ。ＰＶＡ１、ＰＶＡ２、ＥＯ−ＰＯ共重合体、ＰＥＯ１、ジ−２−エチルヘキシルパーオキシジカーボネートの仕込み量は、塩化ビニル単量体１００部に対してそれぞれ、０．０４、０．０３、０．０１、０．００４、０．０５部とした。
【００２０】
重合器を密閉した後内部を真空ポンプで脱気し、次いで塩化ビニル単量体５５０ｋｇ及び脱気後６０℃に温度調節した温水７２５ｋｇを順次仕込んだ。この際塩化ビニル単量体の仕込み開始と同時に攪拌機を稼働した。次いで外部ジャケットにより重合器内温を実施例１では５１．５℃、実施例３では５７℃に昇温後この温度に維持し、重合器内圧が定常圧より９８．０７ｋＰａ低下した時点で重合反応を停止し、未反応単量体を回収して重合反応を終了した。得られたスラリーを脱水、乾燥して実施例１では平均重合度１３００タイプ、実施例３では平均重合度１０００タイプ、の２種の塩化ビニル重合体を得、平均粒子径・粒度分布・多孔度の各種特性値の測定に供した。
【００２１】
さらに得られた塩化ビニル重合体２００ｇにメチルスズメルカブト安定剤１ｇ、ペンタエリスリトール系滑剤０．２ｇ及びポリエチレン系滑剤０．４ｇを添加し、十分攪拌混合して組成物を得、加工性・熱的安定性・物性の評価に供した。
（実施例２及び４）ＰＶＡ１の代わりに鹸化度が８０％、平均重合度が２０００であるＰＶＡ（これをＰＶＡ３という）を、ＰＶＡ２の代わりに鹸化度が３８％、平均重合度が６００であるＰＶＡを、それぞれ用い、それ以外は実施例１及び３と同様にして実施例２では平均重合度１３００タイプ、実施例４では平均重合度１０００タイプ、の２種の塩化ビニル重合体及び組成物を得、各種特性値の測定、加工性評価・熱的安定性評価・物性評価に供した。
（比較例１）分散剤としてＰＶＡ１の代わりにＰＶＡ３の３％水溶液９．９９ｋｇ（塩化ビニル単量体１００部に対して０．０５５部）及びＰＥＯ１の０．５％水溶液２．２ｋｇ（塩化ビニル単量体１００部に対して０．００２部）の２種のみを用いた以外は実施例１と同様にして平均重合度１３００タイプの塩化ビニル重合体及び組成物を得、各種特性値の測定、加工性評価・熱的安定性評価・物性評価に供した。
（比較例２）分散剤としてＰＶＡ１の代わりにＰＶＡ３の３％水溶液９．８１ｋｇ（塩化ビニル単量体１００部に対して０．０５４部）、ＰＶＡ２の代わりに鹸化度が８８％、平均重合度が２３００であるＰＶＡの３％水溶液２．２ｋｇ（塩化ビニル単量体１００部に対して０．０１２部）、及びＰＥＯ１の０．５％水溶液５．５ｋｇ（塩化ビニル単量体１００部に対して０．００５部）の３種のみを用いた以外は実施例３と同様にして平均重合度１０００タイプの塩化ビニル重合体及び組成物を得、各種特性値の測定、加工性評価・熱的安定性評価・物性評価に供した。
（比較例３）ＰＶＡ１の代わりに鹸化度が８８％、平均重合度が２０００であるＰＶＡを用いた以外は実施例１と同様にして平均重合度１３００タイプの塩化ビニル重合体及び組成物を得、各種特性値の測定、加工性評価・熱的安定性評価・物性評価に供した。
【００２２】
評価結果をまとめて表１に示す。
【００２３】
【表１】

【００２４】
【発明の効果】
表１に示した通り、本発明の実施例ではいずれも加工性及び熱的安定性に優れ、且つ物性低下もないことがわかる。
【００２５】
このように本発明者の方法で得られる塩化ビニル系樹脂は、加工性及び熱的安定性に優れ且つ物性低下もないため特に硬質用途向けとしても好適に使用することができ、従って本発明の工業的価値はすこぶる大きいものである。[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for producing a vinyl chloride resin and a resin composition thereof, and more specifically, a method for producing a vinyl chloride resin excellent in processability and thermal stability and having no deterioration in physical properties, and the resin. The present invention relates to a resin composition.
[0002]
[Prior art]
Since vinyl chloride resin is inexpensive and excellent in quality balance, it is a thermoplastic resin used in a wide variety of fields such as the hard field and the soft field. Examples of the frame, industrial transparent plate, and film include electric wire coating, wrap film, and sheet in the soft field.
[0003]
Vinyl chloride resin as a material is a general-purpose resin that is essential to be inexpensive, but various properties are also required in terms of performance. For example, in the above-mentioned products in the soft application field, high volume resistivity, good plasticizer Absorption, reduction of fish eyes, etc. are mentioned.
[0004]
On the other hand, in the field of hard applications, workability and thermal stability when processing into various molded products, basic physical properties such as tensile strength and impact strength after molding, and the like are required to be good. Various attempts have been made to improve these required characteristics, and many can be seen in the techniques disclosed so far. For example, Japanese Patent Laid-Open No. 9-278964 discloses a method of adding methyl methacrylate / butadiene / styrene copolymer or chlorinated polyethylene to a vinyl chloride resin for improving impact resistance and molding processability, Japanese Patent No. 1584 discloses a method of adding a calcium compound, a zinc compound, an epoxidized vegetable oil, a β-diketone compound, and an ester compound to a vinyl chloride resin in order to improve thermal stability, processability, and the like. The publication discloses a method of blending a chlorinated polyolefin and / or a vinyl ester-ethylene copolymer with a vinyl chloride resin for improving molding processability.
[0005]
However, all of these methods contain various reinforcing agents and additives, and generally a large amount of reinforcing agents and additives are required.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above prior art, and is a method for producing a vinyl chloride resin that is excellent in processability and thermal stability and has no deterioration in physical properties, without blending a large amount of reinforcing agents and additives. And it aims at providing the composition containing the resin.
[0007]
[Means for Solving the Problems]
As a result of intensive studies on the above-described quality requirements, that is, processability and thermal stability, and a method for producing a vinyl chloride resin having no deterioration in physical properties and its composition, the present inventors have found a specific dispersant. By using a vinyl chloride polymer produced by suspension polymerization in combination for hard applications, it is possible to obtain a vinyl chloride resin composition excellent in the required characteristics without causing problems of reinforcing agents and additives. The present inventors have found that this is possible and have arrived at the present invention. That is, in the present invention, when suspension polymerization of a vinyl chloride monomer or a mixture of a monomer copolymerizable with vinyl chloride and a vinyl chloride monomer in an aqueous medium, A suspension dispersion stabilizer (a) having a saponification degree of 70 to 100 parts by weight with respect to 100 parts by weight of a copolymerizable monomer and a vinyl chloride monomer (hereinafter simply referred to as a vinyl chloride monomer). 85%, partially saponified polyvinyl chloride having an average degree of polymerization of 1500 to 2500, 0.03 to 0.08 parts by weight, (b) partially saponified poly having a degree of saponification of 33 to 70% and an average degree of polymerization of 200 to 1000 Ethylene oxide and propylene oxide, 0.01 to 0.05 parts by weight of vinyl acetate, (c) a 5% by weight aqueous solution has a viscosity of 50 to 5500 mPa · s, and a propylene oxide content of 5 to 95 mol% 0.003 to 0.02 part by weight of a copolymer of (d), and 0.001 to 0.02 part by weight of polyethylene oxide having an average molecular weight of 4 to 5 million. The manufacturing method (Claim 1 ) is the content.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[0009]
For the production of the vinyl chloride polymer used in the present invention, it is essential to use these four types of dispersants in combination.
(A) may be referred to as partially saponified polyvinyl acetate (hereinafter abbreviated as PVA), which is most commonly used when producing a vinyl chloride polymer. The saponification degree of (a) is 70 to 85%. If the degree of saponification is less than 70%, the surface activity becomes too strong and it is difficult to dissolve in water, so that the handling is difficult. If the degree of saponification exceeds 85%, the polymerization reaction does not proceed stably due to insufficient surface activity. The amount of (a) is 0.03 to 0.08 parts by weight, preferably 0.04 to 0.06 parts by weight, based on 100 parts by weight of the vinyl chloride monomer. If this amount is less than 0.03 parts by weight, the polymerization reaction cannot proceed stably, and if it exceeds 0.08 parts by weight, the resulting dispersant film on the resin surface becomes too thick, which adversely affects workability. Effect. Furthermore, the average degree of polymerization of this (a) is 1500-2500, Preferably it is 1800-2200. If the average degree of polymerization is less than 1500, it is necessary to increase the amount of use in order to allow the polymerization reaction to proceed stably. As a result, the resin surface dispersant film becomes too thick, and if the average degree of polymerization exceeds 2500, it is used. Even if the amount is small, the thickness of the resin surface dispersant film becomes too thick.
Although (b) can be said to be a PVA suitable for making the inside of the resin highly porous for improving processability, it is very difficult to make the polymerization reaction proceed stably by itself, as shown in (a) It is necessary to use PVA or the like together. The degree of saponification of (b) is 33 to 70%. If the degree of saponification is less than 33%, the solubility in water or the swellability is too low, and the effect of increasing the porosity inside the resin is difficult to be exhibited. On the other hand, when the degree of saponification exceeds 70%, the solubility in the monomer is substantially lost, and the effect of making the inside of the resin porous cannot be expected. The amount of (b) is 0.01 to 0.05 parts by weight, preferably 0.02 to 0.04 parts by weight, based on 100 parts by weight of the vinyl chloride monomer. If this amount is less than 0.01 part by weight, the porosity inside the resin will not be sufficient, and if it exceeds 0.05 part by weight, it will be difficult to make the polymerization reaction proceed stably. Furthermore, the average degree of polymerization of (b) is 200 to 1000, preferably 300 to 700. If the average degree of polymerization is less than 200, the solubility in the monomer is too high and the monomer oil droplets generated at the initial stage become unstable, and the polymerization reaction cannot proceed normally. On the other hand, if the average degree of polymerization exceeds 1000, the solubility in the monomer is too low to increase the porosity inside the produced resin.
[0010]
(C) Copolymer of ethylene oxide and propylene oxide (hereinafter abbreviated as EO-PO copolymer) collides with high surface activity comparable to PVA and monomer oil droplets covered with PVA. Shows two types of characteristics of the effect of suppressing fusion (oil droplet protecting power). The viscosity of 5% by weight aqueous solution of (C) is 50 to 5500 mPa · s, preferably 2500 to 5500 mPa · s. When the viscosity of a 5% by weight aqueous solution is less than 50 mPa · s and exceeds 5500 mPa · s, the polymerization reaction does not proceed stably and abnormal polymerization occurs. The amount of (c) is 0.003 to 0.02 parts by weight with respect to 100 parts by weight of the vinyl chloride monomer. If this amount is less than 0.003 parts by weight, the polymerization reaction does not proceed stably and abnormal polymerization occurs, and if it exceeds 0.02 parts by weight, the particle size of the resulting resin becomes very small. Further, the content of propylene oxide (hereinafter abbreviated as PO) in (c) is 5 to 95 mol%. If it is less than 5 mol%, the properties of the EO-PO copolymer exhibiting a surface activity as high as PVA will not be exhibited. On the other hand, if it exceeds 95 mol%, the viscosity is lowered, the oil droplet protecting power is not expressed, and abnormal polymerization occurs.
[0011]
Unlike the other dispersants, the dispersant (d) has almost no surface-active ability. It is also characterized by a very high molecular weight and thus a very thickening effect, and the monomer oil droplets localized on the water side of the water / monomer oil droplet interface and covered with PVA or the like. The effect of suppressing fusion by collision is very high. In addition, because of its extremely high viscosity, this fusion suppressing effect is exhibited in a very small amount. This action makes it possible to greatly reduce the amount of other dispersants used. In particular, reducing the amount of the dispersant as in (a) used here is beneficial in that it makes the surface of the dispersant film thinner. . The amount of (d) is 0.001 to 0.02 parts by weight, preferably 0.003 to 0.008 parts by weight, based on 100 parts by weight of the vinyl chloride monomer. If this amount is less than 0.001 part by weight, the thickening effect peculiar to this dispersant is poor, and a large amount of other dispersant, particularly (a) type dispersant is required. On the other hand, if it exceeds 0.01 parts by weight, the effect of improving the polymerization stability is saturated, and the particle size distribution of the produced resin becomes very wide. Furthermore, the average molecular weight of this (d) is 4-5 million. If the average molecular weight is less than 4,000,000, it is necessary to increase the amount of use in order to obtain a sufficient fusion-inhibiting effect as described above or increase the dispersant as in (a). Thickness increases. If the average molecular weight exceeds 5,000,000, the thickness of the resin surface dispersant film becomes too thick and the viscosity of the aqueous solution becomes remarkably high, which makes it difficult to handle.
[0012]
The monomer used for producing the vinyl chloride polymer used in the present invention is a monomer mainly composed of vinyl chloride. Specifically, the vinyl chloride monomer alone or vinyl chloride is used. It is a mixture of a monomer copolymerizable with vinyl chloride and a vinyl chloride monomer, containing 70% by weight or more.
[0013]
Examples of monomers copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate, α-olefins such as ethylene, propylene, and isobutyl vinyl ether, 1-chloropropylene, and 2-chlorobutylene. Examples include chlorinated olefins, (meth) acrylic acid esters such as methyl (meth) acrylate, maleic anhydride, acrylonitrile, styrene, vinylidene chloride, and these may be used alone or in combination of two or more. It is also possible.
[0014]
A known technique can be arbitrarily used for preparing the raw materials for producing the vinyl chloride polymer used in the present invention. For example, the most common method is to charge the monomer after adding water first, the method to charge the water after charging the monomer first for the purpose of shortening the time to raise the temperature to the polymerization temperature, and further charging For the purpose of shortening the temperature raising time, a method of charging the monomer and hot water at the same time can be used.
[0015]
The heat of the polymerization reaction may be removed by a conventional method, for example, heat removal using an external or internal jacket, a method using a reflux condenser, or the like.
[0016]
Furthermore, polymerization initiators, polymerization degree regulators, chain transfer agents, pH regulators, gelling improvers, antistatic agents, emulsifiers, stabilizers, scales conventionally used for the polymerization or copolymerization of vinyl chloride monomers As for the inhibitor and the like and the charging method thereof, any known technique can be arbitrarily used without any trouble, and the amount used thereof can also follow a conventionally known method.
[0017]
In the present invention, a vinyl chloride resin composition which is excellent in processability and thermal stability and has no deterioration in physical properties by blending arbitrary stabilizers and lubricants with the vinyl chloride resin thus produced. Can be obtained. Conventionally known stabilizers such as tin-based stabilizers and lead-based stabilizers can be arbitrarily used without any problem, and the amount of the stabilizer used can also follow a conventionally known method. As the lubricant, a conventionally known one such as a fatty acid ester lubricant or an olefin lubricant can be arbitrarily used without any problem, and the amount of the lubricant used can be in accordance with a conventionally known method. Although it does not specifically limit about the use of this resin composition, It can use suitably in a hard use especially from the resin quality.
[0018]
【Example】
In order to describe the present invention more specifically, examples and comparative examples are shown below, but these examples do not limit the present invention. 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. Measurement of characteristic values of the obtained vinyl chloride resin and evaluation of processability, thermal stability and physical properties of the composition were carried out by the following methods.
(1) Average particle size and particle size distribution Based on JIS K-6721, using 42, 60, 80, 100, 120, 145, and 200 mesh sieves, sieving with a sieve shaker, 50% The passage diameter was defined as the average particle diameter (μm).
(2) Porosity
Using an AMINCO mercury intrusion porosimeter (type 5-7118), the volume of mercury that is intruded into the vinyl chloride resin at an absolute pressure of 31 to 1011 psi (pore diameter 0.175 to 5.65 μm) is measured. The amount of mercury injected (cc) per 100 g of the vinyl chloride resin was calculated.
(3) 0.5 parts of an organic tin stabilizer, 0.1 part of a fatty acid ester lubricant and 0.2 part of a polyethylene lubricant are added to 100 parts of a processable vinyl chloride resin, and after sufficiently stirring and mixing, the surface temperature is adjusted. It put into an 8-inch roll adjusted to 170 ° C / 180 ° C / 190 ° C. A roll sheet having a thickness of about 0.5 mm is taken out by kneading at each temperature for 5 minutes, the finished state of the sheet is visually confirmed, and workability is evaluated in three stages according to the following evaluation criteria: ○, Δ, × .
[0019]
○: Thoroughly kneaded and a uniform sheet is obtained Δ… Slightly insufficiently kneaded and non-uniform portions are seen in the sheet ×× Kneading is insufficient and the sheet has holes everywhere (4) Heat After adding 0.5 parts of an organic tin stabilizer, 0.1 part of a fatty acid ester lubricant, and 0.2 part of a polyethylene lubricant to 100 parts of a vinyl chloride resin and thoroughly stirring and mixing, 60 g of this mixture (average A composition using a vinyl chloride resin having a polymerization degree of 1300) or 62 g (composition using a vinyl chloride resin having an average polymerization degree of 1000 type) was put into a laboratory plastmill tester manufactured by Toyo Seiki Co., Ltd. The time from when the vinyl chloride resin composition was introduced to when the torque started rising was measured under the conditions of a rotation speed of 50 rpm and a chamber temperature of 180 ° C. The longer this time, the higher the thermal stability.
(5) Evaluation of physical properties After adding 0.5 parts of an organic tin stabilizer, 0.1 part of a fatty acid ester lubricant, and 0.2 part of a polyethylene lubricant to 100 parts of a vinyl chloride resin, and sufficiently stirring and mixing the surface temperature, It put into an 8-inch roll adjusted to 190 ° C. The roll sheet having a thickness of about 0.5 mm was taken out by kneading for 5 minutes at each temperature. The sheets were stacked and preheated at 200 ° C. for 6 minutes, and a 1 mm thick plate was produced by hot pressing at a surface pressure of 4.9 MPa for 2 minutes. A JIS-2 type tensile test piece was prepared from the obtained plate and tested at a test speed of 10 mm / min in accordance with JIS-K7113 to measure yield point strength, 1% modulus, breaking strength, and elongation at break. “%” In the 1% modulus represents the ratio of elongation to the reference length.
(Examples 1 and 3)
In a stainless steel polymerization vessel having an internal volume of 2000 L equipped with a stirrer, 7.33 kg of a 3% aqueous solution of PVA (referred to as PVA1) having a saponification degree of 74% and an average polymerization degree of 2000, a saponification degree of 56%, 0.165 kg of PVA having an average degree of polymerization of 300 (referred to as PVA2), 2.75 kg of a 2% aqueous solution of an EO-PO copolymer having a PO content of 50 mol% and a 5% aqueous solution having a viscosity of 3000 mPa · s, A 0.4% 0.5% aqueous solution of polyethylene oxide having an average molecular weight of 4.5 million (referred to as PEO1) and 0.393 kg of an isoparaffin solution in which di-2-ethylhexyl peroxydicarbonate was dissolved at a concentration of 70% were charged. . The charged amounts of PVA1, PVA2, EO-PO copolymer, PEO1, and di-2-ethylhexyl peroxydicarbonate are 0.04, 0.03, and 0.01, respectively, with respect to 100 parts of vinyl chloride monomer. 0.004, 0.05 part.
[0020]
After the polymerization vessel was sealed, the inside was degassed with a vacuum pump, and then 550 kg of vinyl chloride monomer and 725 kg of warm water adjusted to 60 ° C. after degassing were sequentially charged. At this time, the stirrer was operated simultaneously with the start of the charging of the vinyl chloride monomer. Next, the temperature inside the polymerization reactor was raised to 51.5 ° C. in Example 1 and 57 ° C. in Example 3 by an external jacket, and maintained at this temperature, and the polymerization reaction was performed when the polymerization vessel internal pressure decreased 98.07 kPa from the steady pressure. The polymerization reaction was terminated by recovering unreacted monomers. The obtained slurry was dehydrated and dried to obtain two types of vinyl chloride polymers having an average degree of polymerization of 1300 in Example 1 and an average degree of polymerization of 1000 in Example 3, and an average particle size, particle size distribution, and porosity. It was used for measurement of various characteristic values.
[0021]
Furthermore, 1 g of methyltin mercapto stabilizer, 0.2 g of pentaerythritol lubricant and 0.4 g of polyethylene lubricant were added to 200 g of the obtained vinyl chloride polymer, and the mixture was sufficiently stirred and mixed to obtain a composition. It was used for evaluation of mechanical stability and physical properties.
(Examples 2 and 4) Instead of PVA1, PVA having an saponification degree of 80% and an average polymerization degree of 2000 (referred to as PVA3) is substituted with PVA2, and the saponification degree is 38% and the average polymerization degree is 600. the PVA, used, respectively Re its otherwise examples 1 and 3 and example 2, an average polymerization degree of 1300 type in the same manner, two vinyl chloride polymer having an average polymerization degree of 1000 type, in examples 4 and The composition was obtained and subjected to measurement of various characteristic values, processability evaluation, thermal stability evaluation, and physical property evaluation.
(Comparative example 1) Instead of PVA1 as a dispersant, 9.9 kg of a 3% aqueous solution of PVA3 (0.055 parts relative to 100 parts of vinyl chloride monomer) and 2.2 kg of a 0.5% aqueous solution of PEO1 (vinyl chloride) A vinyl chloride polymer and a composition having an average degree of polymerization of 1300 type were obtained in the same manner as in Example 1 except that only two types (0.002 parts per 100 parts of monomer) were used, and various characteristic values were measured. The material was subjected to processability evaluation, thermal stability evaluation, and physical property evaluation.
(Comparative Example 2) As a dispersant, 9.81 kg of a 3% aqueous solution of PVA3 instead of PVA1 (0.054 parts relative to 100 parts of vinyl chloride monomer), a saponification degree of 88% instead of PVA2, and an average degree of polymerization 2.2 kg of a 3% aqueous solution of PVA with a 2300 (0.012 parts per 100 parts vinyl chloride monomer) and 5.5 kg of a 0.5% aqueous solution of PEO1 (100 parts vinyl chloride monomer) Except for using only 0.005 part), a vinyl chloride polymer and a composition having an average polymerization degree of 1000 type were obtained in the same manner as in Example 3, and measurement of various characteristic values, evaluation of workability, and thermal properties were obtained. It used for stability evaluation and physical-property evaluation.
(Comparative Example 3) A vinyl chloride polymer having an average polymerization degree of 1300 type and a composition were obtained in the same manner as in Example 1 except that PVA having a saponification degree of 88% and an average polymerization degree of 2000 was used instead of PVA1. They were used for measurement of various characteristic values, processability evaluation, thermal stability evaluation, and physical property evaluation.
[0022]
The evaluation results are summarized in Table 1.
[0023]
[Table 1]

[0024]
【The invention's effect】
As shown in Table 1, it can be seen that all of the examples of the present invention are excellent in workability and thermal stability and have no deterioration in physical properties.
[0025]
Thus, the vinyl chloride resin obtained by the method of the present inventor is excellent in processability and thermal stability and does not deteriorate in physical properties, so that it can be suitably used particularly for hard applications. Industrial value is tremendous.

Claims (1)

塩化ビニル単量体または塩化ビニルと共重合可能な単量体と塩化ビニル単量体との混合物を水性媒体中で懸濁重合させるに際し、塩化ビニル単量体または塩化ビニルと共重合可能な単量体と塩化ビニルとの混合物１００重量部に対し、懸濁分散安定剤として、（ａ）鹸化度が７０〜８５％、平均重合度が１５００〜２５００である部分鹸化ポリ酢酸ビニル０．０３〜０．０８重量部、（ｂ）鹸化度が３３〜７０％、平均重合度が２００〜１０００である部分鹸化ポリ酢酸ビニル０．０１〜０．０５重量部、（ｃ）５重量％水溶液の粘度が５０〜５５００ｍＰａ・ｓであり、プロピレンオキサイド含量が５〜９５モル％である、エチレンオキサイドとプロピレンオキサイドとの共重合体０．００３〜０．０２重量部、（ｄ）平均分子量が４００〜５００万であるポリエチレンオキサイド０．００１〜０．０２重量部、を用いることを特徴とする塩化ビニル系樹脂の製造方法。  When a vinyl chloride monomer or a mixture of a monomer copolymerizable with vinyl chloride and a vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium, a monomer copolymerizable with the vinyl chloride monomer or vinyl chloride is used. 0.03 to partially saponified polyvinyl acetate having a saponification degree of 70 to 85% and an average polymerization degree of 1500 to 2500 as a suspension dispersion stabilizer with respect to 100 parts by weight of a mixture of the monomer and vinyl chloride. 0.08 parts by weight, (b) 0.01 to 0.05 parts by weight of partially saponified polyvinyl acetate having a saponification degree of 33 to 70% and an average polymerization degree of 200 to 1000, and (c) the viscosity of a 5% by weight aqueous solution. Having a propylene oxide content of 5 to 95 mol%, a copolymer of ethylene oxide and propylene oxide of 0.003 to 0.02 parts by weight, and (d) an average molecular weight of 400 Method for producing a vinyl chloride resin which is characterized by using a 0.001 to 0.02 parts by weight of polyethylene oxide, 5,000,000.