1250122 7641 pif 1 玫、發明說明： 發明領域 本發明是關於可封閉容器開口部之合成樹脂製蓋、合成 樹脂製盖之製造方法及其製造裝置。 發明背景 請參照第12圖所示，係爲習知之合成樹脂製蓋之實施例。 在此例中所不之封閉裝置之合成樹脂製蓋51係具有頂板(top plate)部32，以及由其周緣垂下之筒部33。筒部33利用水平 模痕（score)36區分成主體38的上半部，以及利用多個細的橋 接部(bridge)37連接位於主體38下端的TE環(TE ring)部39。 在主體38之內壁面形成可與容器開口之公螺紋相互螺合 的螺紋部40。在TE環部39之內壁面設有多個薄板狀的護耳 (tab)41，以在容器上進行蓋51之開栓時防止TE環部39之移 動。 在頂板部32之內面形成突出之環狀的內側密封（seal)部 54，以在安裝蓋51於容器開口部之際，嵌入容器開口部內。 內側密封部54係形成爲當嵌入容器開口部內之際，可與 容器開口部外周之內壁面無間隙地接觸。 可安裝上述合成樹脂製蓋的容器，特別是利用聚乙烯對 苯二酸脂等的合成樹脂所形成之容器，其開口部難以完全做 成固定之厚度或形狀，因而使容器具有變異性（variability)之 尺寸。 在此情形時，對應容器開口部內面之內側密封部的押壓 力在局部的部位會變高，而使開栓轉矩（torque)會變得過大， 進而在內側密封部與容器開口部之間產生間隙及降低其密封 性。 1250122 7641 pif 1 發明槪述 鑑於上述事情，本發明之目的如下所述。 (1) 本發明提供一種合成樹脂製蓋、此蓋之製造方法及其 製造裝置，以使開栓轉矩即使在具有尺寸變異性之容器之情 形下也可維持於所定之値。 (2) 本發明提供一種具有優良密封性能之合成樹脂製蓋、 此蓋之製造方法及其製造裝置。 本發明的合成樹脂製蓋係具有頂板部以及由其周緣垂下 的筒部，其特徵爲在頂板部之內面形成突出之可嵌入容器開 口部之環狀內側密封部，且於內側密封部之基端附近形成比 其他部分薄之薄壁部。 在此合成樹脂蓋中，薄壁部的內側密封部的曲折剛性係 設定爲低的，因而使內側密封部具有完全之柔軟性 (pliability) 〇 因而，當蓋安裝於容器開口部時內側密封部可輕易對應 容器開口部之內面形狀進行彎曲變形，並可在周緣方向上以 一定之押壓力與容器開口部內面相接觸。 因此，即使在具有尺寸變異性之容器之情形下，開栓轉 矩可維持於所定之値，而使密封性得到顯著的提升。 薄壁部係形成於內側密封部之外周，且於薄壁部上形成 有薄化凹部。 本發明之合成樹脂製蓋的製造方法係製造具有頂板部以 及由其周緣垂下的筒部，且在頂板部之內面形成突出之環狀 的內側密封部，及於內側密封部之基端附近形成比其他部分 薄之薄壁部的合成樹脂製蓋的製造方法，此方法係使用形狀 切合前述蓋的內面形狀的內面側模具及形狀切合前述蓋的外 1250122 7641 pif 1 面形狀的外面側模具，此方法之特徵係爲，提供具備有形狀 切合前述內側密封部的內面形狀的內面側模具本體及形狀切 合前述內側密封部的外面形狀的外筒部件的內面側模具，且 外筒部件與內面側模具本體在沿著內側密封部之突出方向係 爲可進行相對移動的，再於內面側模具與外面側模具之間的 間隙中塡充合成樹脂材料，並於成形之後，由所成形之蓋處 拔出內面側模具，即外筒部件與內面側模具本體在配置於可 朝內側密封部之突出端之內方進行移動之位置後，進行內面 側模具之拔出。 在此拔出之過程中包括由內側密封部之前端附近朝內方 移動，內側密封部之外徑不會因此變小，因此在內側密封部 不會增加過大的力量而可順利的進行內面側模具的拔出。 因而，可防止在內側密封部上發生如凹部等的異常突出 部分之形成、龜裂等的破損、伸展變形、斷裂等起因爲內側 密封部之對應於容器開口部內面的局部押壓力過大所造成之 內側密封部的變形或破損，可防止內側密封部與容器開口部 內面之間產生間隙、並維持開栓轉矩於所設定之値進而提高 密封性能。 本發明之合成樹脂製蓋之製造裝置係用以製造具有頂板 部以及由其周緣垂下的筒部，且在頂板部之內面形成突出之 環狀的內側密封部，及於內側密封部之基端附近形成比其他 部分薄之薄壁部的合成樹脂製蓋的合成樹脂蓋製造裝置，此 裝置係具備有形狀切合前述蓋之內面形狀之內面側模具及形 狀切合前述蓋之外面形狀的外面側模具，其特徵爲具備有形 狀切合內側密封部之內面形狀之內面側模具本體及形狀切合 內側密封部之外面形狀之外筒部件的內面側模具，且外筒部 1250122 7641 pif 1 件與內面側模具主體係可沿著內側密封部之突出方向進行相 對移動。 圖式之簡單說明 第1圖所示爲本發明之一較佳實施例之合成樹脂製蓋的 剖面圖。 第2圖所示爲第1圖所示之合成樹脂製蓋的局部放大圖。 第3圖所示爲本發明之一較佳實施例之合成樹脂製蓋之 製造裝置的剖面圖。 第4圖所示爲第3圖所示之製造裝置之動作的說明圖。 第5圖所示爲第3圖所示之製造裝置之動作的說明圖。 第6圖所示爲第3圖所示之製造裝置之動作的說明圖。 第7圖所示爲第3圖所示之製造裝置之動作的說明圖。 第8圖所示爲第3圖所示之製造裝置之動作的說明圖。 第9圖所示爲本發明之其他較佳實施例之合成樹脂製蓋 的局部放大圖。 第10圖所示爲本發明之其他較佳實施例之合成樹脂製蓋 的局部放大圖。 第Π圖所示爲本發明之其他較佳實施例之合成樹脂製蓋 的局部放大圖。 第12圖所示爲習知之合成樹脂製蓋之實施例的剖面圖。 圖式之標記說明= 1 :製造裝置 2:內面側模具 3 =外面側模具 4:端部側模具 4a :筒狀部件 1250122 7641 pif 1 5:內面側模具主體 6:外筒部件 8 :軸承 9 :頂蓋部 10 :軸承插通部 11 :頂蓋部收容部 12 :內側密封部形成缺口 12a :薄化凹口形成凸部 13 :外筒部件插通部 14 :成形空間 31 ， 51 :蓋 32 :頂板部 33 :筒部 34，54 :內側密封部 34a，44a，54a，65a :薄化凹部 34b :接觸凸部 34c :突出端 34d :上緣部 34e :底部 34f，44f :下緣部 34g :凸部 35，45，55，65 :薄壁咅^ 36 :水平模痕 37 :橋接部 38 :主體 39 : TE環部 1250122 7641 pif 1 4〇 :螺紋 41 :護耳 42 :外側密封部 A:突出長度 B:最大傾斜角度 C :深度 D :厚度 E :寬度 較佳實施例之詳細說明 第1圖與第2圖所示爲合成樹脂製蓋的一實施例，在此 所不:之蓋31係爲被稱爲布拉吉蓋（〇ne -piece dress cap)式樣的 蓋，其具有圓盤狀的頂板部32及由其周緣垂下之筒部33。 筒部33利用水平模痕36區分成主體38的上半部，以及 利用多個細的橋接部(bridge)37連接於主體38下端的證明有 無損壞環部（Tamper-Evidence Ring)(以下簡稱TE環部）39。 在主體38之內壁面形成螺紋部40。沿著TE環部39之內 壁面之周緣方向設有多個可朝內方起伏之板狀的護耳41。 在頂板部32之內面形成各自向垂直方向下方突出之環狀 的內側密封部34，以在安裝蓋31於容器開口部之際，嵌入容 器開口部內。 內側密封部34之突出長度，即在第2圖所示之突出長度 A較佳介於2.5mm〜5.5mm之間（更佳係介於3mm〜5mm之 間，最佳爲介於3.5mm〜4.5mm之間）。此突出長度A未達到 上述範圍時，在蓋開栓之際，會提前解除容器之密封，而使 其證明有無損壞（Tamper-Evidence)性降低。 又突出長度A超過上述範圍時’在安裝蓋之際’內側密 10 1250122 7641 pif 1 封部34會與待嵌入之容器開口部不吻合。 本實施例之合成樹脂製蓋係在內側密封部34之基端附近 的外周形成整周薄化之薄化凹部34a，此薄化凹部34a之形成 係將部分的內側密封部34進行薄壁化處理以形成比其他部分 薄之薄壁部35,而且，在內側密封部34之基端部的更外周側， 如第2圖所示，係環狀形成剖面爲半圓狀的凸部34g。 薄化凹部3如係形成高於內側密封部34之柔軟性的薄壁 部35 ’其具有在內側具彎曲之截面形狀的上緣部34d、沿著 垂直方向之底部34e、以及在外側具彎曲之截面形狀的下緣部 34f。 薄化凹部34a係形成在相對於下緣部34f外面之垂直方向 的最大傾斜角度，即在第2圖中所示之最大傾斜角度B較佳 爲90度以下（更加爲6〇度以下，最佳爲30度以下）。 當此最大傾斜角度B超過上述範圍時，則會在蓋成形之 際’蓋成形用模具會在下緣部34f停止，進而引起內側密封部 34之變形或斷裂。 薄化凹部34a之深度，即在第2圖中所示之深度C較佳 係介於0.1mm〜2mm之間（更佳係介於0.3mm〜1.5mm之間， 最佳係介於〇.5mm〜1mm之間）。 當此深度C未達到上述範圍時，會降低薄壁部35之於內 側密封部34之柔軟性，而導致蓋31的開栓轉矩的增加。且 同時會降低蓋31之密封性。 又，當此深度C超過上述範圍時，會使薄壁部35之於內 側密封部34之強度無法發揮完全，而在內側密封部34嵌入 容器開口部之際的內側密封部34之變形（底部彎曲變形等）， 進而降低其密封性。 11 1250122 7641 pif 1 薄壁部35之厚度，即在第2圖中所示之厚度D較佳係介 於1mm〜2.2mm之間（更佳係介於1.2mm〜2mm之間，最佳 係介於1.4mm〜1.8mm之間）。 當此厚度D未達到上述範圍時，會使薄壁部35之於內側 密封部34之強度無法發揮完全，而在內側密封部34嵌入容 器開口部之際的內側密封部34之變形（底部彎曲變形等）， 進而降低其密封性。 又，當此厚度D超過上述範圍時，會降低薄壁部35之於 內側密封部34之柔軟性，而導致蓋31的開栓轉矩的增加。 且同時會降低蓋31之密封性。 薄化凹部34a之寬度，即在第2圖中所示之寬度E較佳 係介於0.5mm〜2.5mm之間（更佳係介於0.8mm〜2mm之間， 最佳係介於1mm〜1.5mm之間）。 當此深度E未達到上述範圍時，會降低薄壁部35之於內 側密封部34之柔軟性，而導致蓋31的開栓轉矩的增加。且 同時會降低蓋31之密封性。 又，當此深度E超過上述範圍時，會使薄壁部35之於內 側密封部34之強度無法發揮完全，而在內側密封部34嵌入 容器開口部之際的內側密封部34之變形（底部彎曲變形等）， 進而降低其密封性。 在薄化凹部34a之形成的同時，內側密封部34之下部， 由基端部附近向外方突出之處，形成接觸凸部34b以在安裝 蓋之際與容器開口部內壁相接觸。 內側密封部34上形成截面形狀略呈圓弧狀彎曲的接觸凸 部34b可以有較佳之密封性。 又，內側密封部34之最大外徑可與待安裝此蓋31之容 12 1250122 7641 pif 1 器開口部內徑約略相等，較佳之設定略大於容器開口部內徑。 在靠近內側密封部34之頂板部外周側上’形成向下方突 出的環狀外側密封部42。外側密封部42係在蓋安裝之際形成 與容器開口部之外周面相接觸。 蓋31之構成材料較佳爲聚丙烯、高密度聚乙烯。 接著對上述蓋31之製造方法及其製造裝置進行說明。 第3圖所示爲本發明之一較佳實施例之合成樹脂製蓋之 製造裝置的剖面圖。在此所示之製造裝置1係爲用以製造於 頂板部32內面形成有突出的環狀內側密封部34的蓋31 ’其 中此製造裝置1之結構具有用以形成蓋31之內面側的內面側 模具2、用以形成蓋31之外面側的外面側模具3、以及用以 形成蓋31之端部的端部側模具4。 外面側模具3係形成具有切合蓋31之外形之內面形狀之 有底筒狀節結構。 內面側模具2係具有內面側模具本體5及設於此本體5 之外周的外筒部件6。 內面側模具本體5係具有軸承8及設於軸承8之前端（在 第3圖之下端）的圓筒狀頂蓋(head)部9。 頂蓋部9之外徑係形成大於軸承8之外徑，且具有沿著 蓋31之內側密封部34內面形狀的外面形狀。 外筒部件6係形成具有切合頂板部32之內側密封部34 以外之部分及筒部33之內面形狀的外面形狀的筒狀結構。在 其內部係形成可插通軸承8之軸承插通部1〇，及可收容頂蓋 部9之頂蓋部收容部11。 頂蓋部收容部11係形成在其軸方向（上下方向）的長度 至少長於頂蓋部9之軸方向長度，在其下端部附近的內面全 13 1250122 7641 pif 1 周上形成具有內面形狀切合內側密封部34外面形狀的內側密 封部形成缺口 12 ◦ 在內側密封部形成缺口 12之下部內壁上，沿著薄化凹部 34a形成突出的薄化凹部形成凸部12a之形狀。因此’薄化凹 部形成凸部12a所具有之內徑至少需小於內側密封部34之最 大外徑。 在本較佳實施例中’外筒部件6與內面側模具本體5可 沿著軸方向（即在第3圖中所示之上下方向）進行相對地移 動。 φ 在本較佳實施例中’外筒部件6係可進行相對於內面側 模具本體5之上下方向移動。又，在本發明中，內面側模具 本體5也可以進行相對於外筒部件6之上下方向移動。 以下，在第3圖中所示之實線係爲外筒部件6相對於本 體5進行後退（向上方移動）之狀態，以使本體5位於相對 的下方，蓋31之形狀係沿著內面側模具2與外面側模具3之 間的間隙形成，且此時內面側模具本體5之位置係爲「下方 位置」。 又所示之2點區分線(D1V1de line)係爲外筒部件6相對於 鲁 本體5進行前進（向下方移動）之狀態，此時內面側模具本 體5之位置係爲「上昇位置」。 內面側模具本體5在上昇位置時，頂蓋部9之下端外周 係位於內側密封部34之前端附近，且內側密封部34的彈性 變形係設計爲在內側密封部34上施加朝向半徑方向內方的力 量’以使內側密封部34之突出端34c朝向內方移動。 端邰側模具4係形成筒狀，在其內部之外筒部件插通部1 3 插通外筒部件6。端部側模具4之下端形狀係沿著TE環部39 14 1250122 7641 pif 1 之端部（位於第3圖之上端部）及護耳41而成。 端部側模具4係可相對於內面側模具進行軸方向（上下 方向）的移動，而且，如第5圖所示，在端部側模具4的外 周配置有筒狀部件4a。 成形空間14係由內面側模具2 (當內面側模具本體5位 於下方位置之狀態時）、外面側模具3、以及端部側模具4 $ 間所形成之間隙所構成，且蓋31之形狀係沿著成形空間14 而形成的。 接者’ S靑麥照弟3圖至第8圖，使用上述製造裝置1製 造上述蓋31之情形爲例，並以本發明之一較佳實施例對合成 樹脂製蓋的製造方法進行說明。 請參照第3圖所示，在內面側模具2、外面側模具3、以 及端邰側模具4所構成之成形空間14內，塡充合成樹脂树料 (聚丙嫌、聚乙烯等），進行成形。此時，外筒部件6與內面 側模具本體5之相對位置係將內面側模具本體5固定配置於 下方位置。 在外筒部件6內面的內側密封部形成缺口 12與頂蓋部9 之間的間隙中塡充合成樹脂材料以形成內側密封部34。 蓋31之成形方法較佳係使用壓縮成形法。 以下，對蓋31由內面側模具2及外面側模具3取出之過 程進行詳細的說明。 首先，請參照第4圖與第5圖所示，將蓋31由外面側模 具3中取出，內面側模具2之外筒部件6向下方移動即內面 側模具本體5沿著內側密封部34之突出方向移動，以使內面 側模具本體5配置於上昇位置。 在此上昇位置之際，頂蓋部9下端外周位於內側密封部34 15 1250122 7641 pif 1 之上端附近，且內側密封部34之突出端34c係變成可朝向半 徑方向之內方移動之狀態。 又，端部側模具4相對於內面側模具2進行上昇，以與TE 環部39及護耳分離。 接著，請參照第6圖所示，內面側模具2之全部（內面 側模具主體5及外筒部件6)朝相對於蓋31之上方進行移動。 在內側密封部形成缺口 12之內周形成具有至少小於內側 密封部34最大外徑的內徑的薄化凹部形成凸部12a，當主體5 及外筒部件6朝上方進行移動之際，薄化凹部形成凸部12a會 對內側密封部34 (薄化凹部34a之下緣部34f)施加朝上之力 量。 請參照第7圖所示，此時，內側密封部34發生彈性變形， 以使內側密封部34之前端附近朝向內方移動，而縮小內側密 封部34之外徑。如此，薄化凹部形成凸部12a可使內側密封 部34之接觸凸部34b順利通過。 因此，在拔出內面側模具2時薄化凹部形成凸部12a會對 內側密封部34上施加適當之力道。 又在此過程中，外筒部件也會對護耳41施加朝上之力量， 且端部側模具4已與TE環部39及護耳41形成分離之狀態’ 而使護耳41變成朝向上方進行彈性折疊變形之狀態。因此’ 在拔出內面側模具2時外筒部件6也不會對護耳41施加過大 之力道。 在經過上述之拔出過程之後，如第8圖所示’內面側模 具由蓋31取出，而得到完成後的蓋31。 蓋31在容器開口邰朝向閉栓方向旋轉’藉由盍31之虫累 紋與容器開口部公螺紋之相互鎖合，以將蓋31安裝於容器開 16 1250122 7641 pif 1 口部。 此時，內側密封部34嵌入容器開口部之內部，接觸凸部 34b與容器開口部之內壁進行無間隙接觸，以密封容器開口 部。 在開栓之際，將蓋31朝開栓方向旋轉，Te環部39之上 昇會受阻，且主體38繼續上昇，使TE環部39因橋接部37 之切斷而與主體38分離，如此即可使內側密封部34拔離容 器開口部而解除密封。 本較佳實施例之蓋31係具有頂板部32以及由其周緣垂 下的筒部33 ’且在頂板部32之內面形成突出之環狀內側密封 部34，且於內側密封部34之基端附近形成比其他部分薄之薄 壁部35，此部分之內側密封部34的曲折剛性係設定爲低的， 因而使內側密封部34具有完全之柔軟性。 因而，當蓋31安裝於容器開口部時，內側密封部34可 輕易對應容器開口部之內面形狀，並利用薄壁部35進行彎曲 變形，以在周緣方向上以一定之押壓力與容器開口部內面相 接觸。 例如，當容器開口邰在周緣方向之一部份形成比其他部 分薄的時候，藉由薄壁部35之彎曲變形而使內側密封部34 之前端附近朝向容器開口部之上述薄壁部分改變位置。 因此，此薄壁部份與內側密封部34之容器內面所對應 之押壓力係呈穩定之値，且在此同時可抑制位於薄壁部份以 外之部分所對應之押壓力的降低，使內側密封部34全周可以 一定之押壓力與容器開口部內面相接觸。 如此，即使在具有尺寸變異性之容器之情形下，可防止 因內側密封部34之容器開口部內面對應過大之押壓力而產生 17 1250122 7641 pif 1 之開栓轉矩的上昇，而使開栓轉矩維持於所設定之値。 又，防止內側密封部34之容器開口部內面所對應之押壓 力變成不穩定，可提高內側密封部34之容器開口部所對應之 密封性，並可提高蓋31之密封性能。 又，薄壁部35之形成係在內側密封部34之外周上形成 薄化凹部34a，並於內側密封部34之下部（前端部附近）形 成由基端部附近向外方突出之接觸凸部34b。 因此，當蓋31安裝之際，內側密封部34下部（前端部 附近）可將容器開口部密封，且可於蓋31開栓時，延遲解除 φ 容器之密封狀態，進而提高其證明有無損壞性。 上述較佳實施例之製造方法係爲將內面側模具2由已成 形之蓋31中拔出，外筒部件6與內面側模具本體5到達於內 側密封部34的突出端34c可朝向內方移動之位置之後，內面 側模具2即可由蓋31拔出。 在此拔出之過程中，在缺口 12處所形成之薄化凹部形成 凸部12a會對內側密封部34施加向上方的力道，此時，內側 密封部34之前端附近朝向內方移動，而使內側密封部34之 外徑縮小。 ® 因此，在外筒部件6上形成具有小於內側密封部34最大 外徑之內徑的薄化凹部形成凸部12a，且可在進行內面側模具 2之拔出時，對內面密封部34施加適當的力道以順利拔出。 因而，可防止在內側密封部34上發生凹部等的異常突出 部分之形成、龜裂等的破損、伸展變形、斷裂等現象。 因此，可防止起因爲內側密封部34之對應於容器開口部 內面的局部押壓力過大所造成之內側密封部34之變形（例如 是形成異常突出部分），以使開拴轉矩維持於所設定之値。 18 1250122 7641 pif 1 且在提高內側密封部34之尺寸精密度之際，亦可防止因 內側密封部34之變形或破損（例如龜裂）而在內側密封部34 與容器開口部內面之間產生的間隙，進而得到具有優良密封 性能之蓋31。 在上述實施例之製造裝置1中，內面側模具2係具備有 开多狀切合內側密封部34之內面形狀之頂蓋部9的內面側模具 本體5，以及內面形狀切合內側密封部34之外面形狀之外筒 部件6。且外筒部件6與內面側模具主體5可沿著內側密封部 34之突出方向進行沿上下方向之相對移動，以將內面側模具 2由已成形之蓋31中拔出，當外筒部件6與內面側模具主體 5位於內側密封部34之突出端34c可向內方移動之位置之後， 內面側模具2即可由蓋31內拔出。 因此，不需對內側密封部34施加過大之力量，即可順利 地將內面側模具2拔出，可防止在內側密封部34上發生凹部 等的異常突出部分之形成、龜裂等的破損、伸展變形、斷裂 等現象。 因此，可防止起因爲內側密封部34之對應於容器開口部 內面的局部押壓力過大所造成之內側密封部34之變形或破 損，並可防止在內側密封部34與容器開口部內面之間產生間 隙，以使開栓轉矩可維持於所設定之値且提高其密封性能。 在本發明中並不以上述實施例中所揭露之形成於內側密 封部之薄化凹部爲限，例如，如第9圖之符號44a所示之薄化 凹部，係形成具有一定之傾斜角度的下緣部44f。 又，薄化凹部也可以如第10圖之符號54a所示，係形成 整個向內側彎曲之截面形狀。 又在上述實施例中，雖以於內側密封部之外周形成薄化 19 1250122 7641 pif 1 凹部爲例進行說明，然並不以此爲限。如第11圖所示，也可 以在蓋31之結構上增加於內側密封部34之基端附近的內周 上所形成之薄化凹部64a。另在第9圖至第11圖中的符號45、 55、65皆表示薄壁部。 又在本發明中，薄化凹部之形成位置也可以形成於內側 密封部之內周。 產業上的利用可能性 本發明之合成樹脂製蓋係具有頂板部以及由其周緣垂下 的筒部，且在頂板部之內面形成突出之環狀內側密封部，且 φ 於內側密封部之基端附近形成比其他部分薄之薄壁部，此部 分之內側密封部的曲折剛性係設定爲低的，因而使內側密封 部具有完全之柔軟性。 因而，當蓋安裝於容器開口部時，內側密封部可輕易對 應容器開口部之內面形狀進行彎曲變形，並可在周緣方向上 以一定之押壓力與容器開口部內面相接觸。 因此，即使在具有尺寸變異性之容器之情形下，可防止 內側密封部之容器開口部內面對應之局部押壓力過大，而使 賺轉灘戀獄紅丨1。 * 又可防止內側密封部與容器開口部之間產生間隙，以提 高其密封性能。 又，本發明之合成樹脂製蓋之製造方法係爲將內面側模 具由已成形之蓋拔出，在外筒部件與內面側模具本體到達於 內側密封部的突出端可朝向內方移動之位置之後，內面側模 具即可由蓋拔出，且不需對內側密封部施加過大之力量即可 順利將內面側模具拔出。 因而，可防止在內側密封部上發生凹部等的異常突出部 20 1250122 7641 pif 1 分之形成、龜裂等的破損、伸展變形、斷裂等現象。 因此，可防止起因爲內側密封部之對應於容器開口部內 面的局部押壓力過大所造成之內側密封部之變形或破損，並 可防止在內側密封部與容器開口部內面之間產生間隙，以使 開栓轉矩可維持於所設定之値且提高其密封性能。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin cap that can close an opening of a container, a method of manufacturing a synthetic resin cap, and a manufacturing apparatus therefor. Background of the Invention Referring to Figure 12, there is shown an embodiment of a conventional synthetic resin cover. The synthetic resin cover 51 of the closing device which is not in this example has a top plate portion 32 and a cylindrical portion 33 which is suspended from the periphery thereof. The tubular portion 33 is divided into the upper half of the main body 38 by a horizontal score 36, and the TE ring portion 39 located at the lower end of the main body 38 is connected by a plurality of thin bridges 37. A threaded portion 40 is formed on the inner wall surface of the main body 38 to be screwed to the male thread of the container opening. A plurality of thin plate-shaped tabs 41 are provided on the inner wall surface of the TE ring portion 39 to prevent the movement of the TE ring portion 39 when the lid 51 is opened on the container. A ring-shaped inner seal portion 54 is formed on the inner surface of the top plate portion 32 so as to be fitted into the container opening portion when the cover 51 is attached to the container opening portion. The inner seal portion 54 is formed to be in contact with the inner wall surface of the outer periphery of the container opening without a gap when fitted into the opening of the container. It is possible to mount a container made of the above synthetic resin, in particular, a container formed of a synthetic resin such as polyethylene terephthalate, and it is difficult to completely form a fixed thickness or shape in the opening, thereby making the container variability (variability) The size of the ). In this case, the pressing force of the inner seal portion corresponding to the inner surface of the opening portion of the container becomes higher at a local portion, and the opening torque is excessively increased, and further between the inner seal portion and the container opening portion. Create gaps and reduce their tightness. 1250122 7641 pif 1 Description of the Invention In view of the above, the object of the present invention is as follows. (1) The present invention provides a synthetic resin cover, a method of manufacturing the cover, and a manufacturing apparatus thereof, so that the opening torque can be maintained at a predetermined level even in the case of a container having dimensional variability. (2) The present invention provides a synthetic resin cover having excellent sealing performance, a method of manufacturing the cover, and a manufacturing apparatus therefor. The synthetic resin cover of the present invention has a top plate portion and a tubular portion that is suspended from the periphery thereof, and is characterized in that an annular inner seal portion that can be fitted into the opening of the container is formed on the inner surface of the top plate portion, and is formed in the inner seal portion. A thin portion which is thinner than the other portions is formed near the base end. In the synthetic resin cover, the tortuous rigidity of the inner seal portion of the thin portion is set to be low, so that the inner seal portion has complete flexibility. Therefore, the inner seal portion is attached when the cover is attached to the container opening portion. The inner surface of the opening of the container can be easily bent and deformed, and can be brought into contact with the inner surface of the opening of the container at a constant pressing force in the peripheral direction. Therefore, even in the case of a container having dimensional variability, the opening torque can be maintained at a predetermined level, and the sealing property is remarkably improved. The thin portion is formed on the outer circumference of the inner seal portion, and a thinned concave portion is formed on the thin portion. The method for producing a synthetic resin cap according to the present invention is to manufacture a ring-shaped inner seal portion having a top plate portion and a tubular portion suspended from the peripheral edge thereof, and an inner surface of the top plate portion, and a proximal end portion of the inner seal portion. A method for producing a synthetic resin cover having a thinner portion thinner than the other portions, wherein the inner surface side mold having a shape in which the inner surface of the cover is cut and the outer surface of the outer surface of the cover 1250122 7641 pif 1 are formed in a shape The side mold is characterized in that the inner surface side mold body having the inner surface shape having the shape of the inner surface of the inner side seal portion and the outer surface side mold having the outer shape of the outer shape of the inner side seal portion are provided, and The outer cylinder member and the inner surface side mold body are relatively movable in a direction in which the inner side seal portion protrudes, and the synthetic resin material is filled in a gap between the inner surface side mold and the outer side mold, and is formed. Thereafter, the inner surface side mold is pulled out from the formed lid, that is, the outer cylinder member and the inner surface side mold body are disposed inside the protruding end of the inner side sealing portion. After moving the position, the inner side mold is pulled out. In the process of pulling out, the inner seal portion is moved inwardly from the vicinity of the front end portion, and the outer diameter of the inner seal portion is not reduced. Therefore, the inner seal portion does not increase excessive force and the inner surface can be smoothly performed. Pull out the side mold. Therefore, it is possible to prevent the formation of an abnormal protruding portion such as a concave portion, the breakage of a crack or the like, the stretching deformation, the breakage, and the like in the inner seal portion due to the excessive partial pressure of the inner seal portion corresponding to the inner surface of the opening portion of the container. The deformation or breakage of the inner seal portion prevents a gap between the inner seal portion and the inner surface of the container opening portion, and maintains the opening torque at the set opening to improve the sealing performance. The apparatus for manufacturing a synthetic resin cap according to the present invention is for manufacturing a ring-shaped inner seal portion having a top plate portion and a cylindrical portion suspended from the periphery thereof, and forming an inner surface of the top plate portion, and a base portion of the inner seal portion. A synthetic resin cap manufacturing apparatus for forming a synthetic resin cap having a thinner wall portion thinner than the other portion in the vicinity of the end, the device having an inner surface side mold having a shape in which the inner surface of the cap is cut and having a shape conforming to the outer surface of the cap The outer side mold is characterized in that it has an inner surface side mold main body having a shape in which the inner surface of the inner side seal portion is cut, and an inner surface side mold having a shape in which the outer side of the inner side seal portion is formed, and the outer tube portion 1250122 7641 pif The one piece and the inner side mold main system can be relatively moved along the protruding direction of the inner side seal portion. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing a synthetic resin cover according to a preferred embodiment of the present invention. Fig. 2 is a partially enlarged view showing the synthetic resin cover shown in Fig. 1. Fig. 3 is a cross-sectional view showing a manufacturing apparatus for a synthetic resin cover according to a preferred embodiment of the present invention. Fig. 4 is an explanatory view showing the operation of the manufacturing apparatus shown in Fig. 3. Fig. 5 is an explanatory view showing the operation of the manufacturing apparatus shown in Fig. 3. Fig. 6 is an explanatory view showing the operation of the manufacturing apparatus shown in Fig. 3. Fig. 7 is an explanatory view showing the operation of the manufacturing apparatus shown in Fig. 3. Fig. 8 is an explanatory view showing the operation of the manufacturing apparatus shown in Fig. 3. Fig. 9 is a partially enlarged plan view showing a synthetic resin cover according to another preferred embodiment of the present invention. Fig. 10 is a partially enlarged plan view showing a synthetic resin cover according to another preferred embodiment of the present invention. Fig. 1 is a partially enlarged plan view showing a synthetic resin cover according to another preferred embodiment of the present invention. Fig. 12 is a cross-sectional view showing an embodiment of a conventional synthetic resin cover. Description of the drawings: 1: manufacturing apparatus 2: inner side mold 3 = outer side mold 4: end side mold 4a: cylindrical member 1250122 7641 pif 1 5: inner side mold main body 6: outer cylinder member 8: Bearing 9: top cover portion 10: bearing insertion portion 11: top cover portion accommodating portion 12: inner seal portion forming notch 12a: thinned recess forming convex portion 13: outer cylinder member insertion portion 14: forming space 31, 51 : cover 32 : top plate portion 33 : cylindrical portion 34 , 54 : inner sealing portion 34 a , 44 a , 54 a , 65 a : thinned concave portion 34 b : contact convex portion 34 c : protruding end 34 d : upper edge portion 34 e : bottom portion 34 f, 44 f : lower Edge portion 34g: convex portion 35, 45, 55, 65: thin wall 咅^ 36: horizontal mold mark 37: bridge portion 38: main body 39: TE ring portion 1250122 7641 pif 1 4 〇: thread 41: ear protector 42: outer seal Part A: Projection Length B: Maximum Tilt Angle C: Depth D: Thickness E: Width Description of Preferred Embodiments FIGS. 1 and 2 show an embodiment of a synthetic resin cover, which is not: The cover 31 is a cover called a 〇ne-piece dress cap, and has a disk-shaped top plate portion 32 and a cylindrical portion 33 suspended from the periphery thereof. The tubular portion 33 is divided into the upper half of the main body 38 by the horizontal die mark 36, and the Tamper-Evidence Ring (hereinafter referred to as TE) is connected to the lower end of the main body 38 by a plurality of thin bridges 37. Ring) 39. A threaded portion 40 is formed on the inner wall surface of the main body 38. A plurality of ear protectors 41 which are undulating inwardly are provided along the circumferential direction of the inner wall surface of the TE ring portion 39. An annular inner seal portion 34 that protrudes downward in the vertical direction is formed on the inner surface of the top plate portion 32 so as to be fitted into the container opening portion when the cover 31 is attached to the container opening portion. The protruding length of the inner sealing portion 34, that is, the protruding length A shown in Fig. 2 is preferably between 2.5 mm and 5.5 mm (more preferably between 3 mm and 5 mm, and most preferably between 3.5 mm and 4.5 mm). Between mm). When the protruding length A does not reach the above range, the sealing of the container is released in advance when the opening is opened, so that the Tamper-Evidence is deteriorated. When the length A exceeds the above range, the inner side of the mounting cover is closed. 10 1250122 7641 pif 1 The sealing portion 34 does not coincide with the opening of the container to be embedded. In the synthetic resin cover of the present embodiment, a thinned concave portion 34a which is thinned over the entire circumference is formed on the outer periphery of the proximal end of the inner seal portion 34, and the thinned concave portion 34a is formed to reduce the thickness of the inner seal portion 34. In the outer peripheral side of the base end portion of the inner seal portion 34, as shown in Fig. 2, a convex portion 34g having a semicircular cross section is formed in a ring shape. The thinned recessed portion 3 is formed into a thin portion 35' which is higher in flexibility than the inner seal portion 34, and has an upper edge portion 34d having a curved cross-sectional shape on the inner side, a bottom portion 34e along the vertical direction, and a curved portion on the outer side. The lower edge portion 34f of the cross-sectional shape. The thinned concave portion 34a is formed at a maximum inclination angle with respect to the vertical direction of the outer surface of the lower edge portion 34f, that is, the maximum inclination angle B shown in Fig. 2 is preferably 90 degrees or less (more preferably 6 degrees or less, most Good for 30 degrees or less). When the maximum inclination angle B exceeds the above range, the lid forming mold stops at the lower edge portion 34f, and the inner seal portion 34 is deformed or broken. The depth of the thinned recess 34a, that is, the depth C shown in FIG. 2 is preferably between 0.1 mm and 2 mm (more preferably between 0.3 mm and 1.5 mm, and the optimum is between 〇. 5mm~1mm). When the depth C does not reach the above range, the softness of the thin portion 35 to the inner side seal portion 34 is lowered, resulting in an increase in the opening torque of the cover 31. At the same time, the sealing of the cover 31 is lowered. Further, when the depth C exceeds the above range, the strength of the inner wall portion 34 of the thin portion 35 is not fully achieved, and the inner seal portion 34 is deformed when the inner seal portion 34 is fitted into the opening portion of the container (bottom portion). Bending deformation, etc.), thereby reducing its sealing. 11 1250122 7641 pif 1 The thickness of the thin portion 35, that is, the thickness D shown in Fig. 2 is preferably between 1 mm and 2.2 mm (more preferably between 1.2 mm and 2 mm, the best system) Between 1.4mm~1.8mm). When the thickness D does not reach the above range, the strength of the thin portion 35 to the inner seal portion 34 is not fully achieved, and the inner seal portion 34 is deformed when the inner seal portion 34 is fitted into the opening portion of the container (bottom bend) Deformation, etc.), thereby reducing its tightness. Further, when the thickness D exceeds the above range, the flexibility of the thin portion 35 to the inner seal portion 34 is lowered, and the opening torque of the lid 31 is increased. At the same time, the sealing of the cover 31 is lowered. The width of the thinned concave portion 34a, that is, the width E shown in Fig. 2 is preferably between 0.5 mm and 2.5 mm (more preferably between 0.8 mm and 2 mm, and the optimum is between 1 mm and mm). Between 1.5mm). When the depth E does not reach the above range, the softness of the thin portion 35 to the inner side seal portion 34 is lowered, resulting in an increase in the opening torque of the cover 31. At the same time, the sealing of the cover 31 is lowered. Further, when the depth E exceeds the above range, the strength of the inner wall portion 34 of the thin portion 35 is not fully achieved, and the inner seal portion 34 is deformed when the inner seal portion 34 is fitted into the opening portion of the container (bottom portion). Bending deformation, etc.), thereby reducing its sealing. While the thinned concave portion 34a is formed, the lower portion of the inner side seal portion 34 protrudes outward from the vicinity of the base end portion, and the contact convex portion 34b is formed to come into contact with the inner wall of the container opening portion when the cover is attached. The contact convex portion 34b having a cross-sectional shape slightly curved in the inner seal portion 34 can have a preferable sealing property. Further, the maximum outer diameter of the inner seal portion 34 may be approximately equal to the inner diameter of the opening portion of the cover 12 to be mounted, preferably set to be slightly larger than the inner diameter of the opening portion of the container. An annular outer seal portion 42 that protrudes downward is formed on the outer peripheral side of the top plate portion of the inner seal portion 34. The outer seal portion 42 is formed to come into contact with the outer peripheral surface of the container opening when the cover is attached. The constituent material of the lid 31 is preferably polypropylene or high density polyethylene. Next, a method of manufacturing the above-described cover 31 and a manufacturing apparatus thereof will be described. Fig. 3 is a cross-sectional view showing a manufacturing apparatus for a synthetic resin cover according to a preferred embodiment of the present invention. The manufacturing apparatus 1 shown here is a cover 31 for manufacturing a projecting annular inner seal portion 34 formed on the inner surface of the top plate portion 32. The structure of the manufacturing apparatus 1 has an inner surface side for forming the cover 31. The inner side mold 2, the outer side mold 3 for forming the outer surface side of the lid 31, and the end side mold 4 for forming the end portion of the lid 31. The outer side mold 3 is formed into a bottomed cylindrical joint structure having an inner surface shape which is shaped to conform to the outer shape of the cover 31. The inner surface side mold 2 has an inner surface side mold main body 5 and an outer cylinder member 6 provided on the outer circumference of the main body 5. The inner surface side mold body 5 has a bearing 8 and a cylindrical head portion 9 provided at the front end of the bearing 8 (at the lower end of Fig. 3). The outer diameter of the top cover portion 9 is formed to be larger than the outer diameter of the bearing 8, and has an outer shape along the inner surface of the inner seal portion 34 of the cover 31. The outer tubular member 6 is formed into a tubular structure having an outer shape that cuts a portion other than the inner seal portion 34 of the top plate portion 32 and the inner surface of the tubular portion 33. A bearing insertion portion 1A of the insertable bearing 8 and a top cover portion accommodating portion 11 for accommodating the top cover portion 9 are formed inside. The top cover portion accommodating portion 11 is formed to have a length in the axial direction (up-and-down direction) that is at least longer than the axial direction of the top cover portion 9, and an inner surface shape is formed on the inner surface of the lower end portion at all 13 1250122 7641 pif 1 week. The inner seal portion that cuts the outer shape of the inner seal portion 34 forms a notch 12 ◦. The inner seal portion forms the inner wall of the lower portion of the notch 12, and the thinned concave portion that forms the protrusion along the thinned recess portion 34a forms the shape of the convex portion 12a. Therefore, the thinned recess forming projection 12a has an inner diameter which is at least smaller than the maximum outer diameter of the inner seal portion 34. In the preferred embodiment, the outer cylinder member 6 and the inner surface side mold body 5 are relatively movable in the axial direction (i.e., in the upper and lower directions shown in Fig. 3). φ In the preferred embodiment, the outer cylinder member 6 is movable in the upper and lower directions with respect to the inner surface side mold body 5. Further, in the present invention, the inner-side mold body 5 can be moved in the vertical direction with respect to the outer tubular member 6. Hereinafter, the solid line shown in Fig. 3 is a state in which the outer tubular member 6 is retracted (moved upward) with respect to the main body 5 so that the main body 5 is located below the opposite side, and the shape of the cover 31 is along the inner surface. A gap between the side mold 2 and the outer side mold 3 is formed, and at this time, the position of the inner surface side mold body 5 is "lower position". Further, the two-point line (D1V1de line) is a state in which the outer tube member 6 is advanced (moved downward) with respect to the body 5, and the position of the inner-side mold body 5 is "upward position". When the inner-side mold body 5 is in the raised position, the outer periphery of the lower end of the top cover portion 9 is located near the front end of the inner seal portion 34, and the elastic deformation of the inner seal portion 34 is designed to be applied in the radial direction on the inner seal portion 34. The force of the square is such that the protruding end 34c of the inner seal portion 34 moves inward. The end jaw side mold 4 is formed into a tubular shape, and the cylindrical member insertion portion 1 3 is inserted into the outer cylinder member 6 outside the inside. The shape of the lower end of the end side mold 4 is formed along the end portion of the TE ring portion 39 14 1250122 7641 pif 1 (at the upper end portion of Fig. 3) and the ear protector 41. The end side mold 4 is movable in the axial direction (up and down direction) with respect to the inner surface side mold, and as shown in Fig. 5, the tubular member 4a is disposed on the outer periphery of the end side mold 4. The molding space 14 is constituted by a gap formed between the inner surface side mold 2 (when the inner surface side mold body 5 is at the lower position), the outer side mold 3, and the end side mold 4 $, and the cover 31 The shape is formed along the forming space 14. Next, a case where the above-described cover 31 is manufactured by the above-described manufacturing apparatus 1 will be taken as an example, and a method of manufacturing a synthetic resin cover will be described with reference to a preferred embodiment of the present invention. Referring to Fig. 3, in the molding space 14 formed by the inner surface side mold 2, the outer side mold 3, and the end side mold 4, a synthetic resin tree material (polypropylene, polyethylene, etc.) is filled. Forming. At this time, the relative position of the outer cylinder member 6 and the inner surface side mold main body 5 is such that the inner surface side mold main body 5 is fixedly disposed at a lower position. The inner seal portion of the inner surface of the outer cylinder member 6 is formed with a synthetic resin material in a gap between the notch 12 and the top cover portion 9 to form an inner seal portion 34. The forming method of the lid 31 is preferably a compression molding method. Hereinafter, the process of taking out the lid 31 from the inner surface side mold 2 and the outer surface side mold 3 will be described in detail. First, as shown in FIGS. 4 and 5, the lid 31 is taken out from the outer side mold 3, and the inner side mold 2 is moved downward, that is, the inner side mold main body 5 is along the inner side seal portion. The protruding direction of 34 is moved so that the inner-side mold body 5 is placed at the raised position. At the ascending position, the outer periphery of the lower end of the top cover portion 9 is located near the upper end of the inner seal portion 34 15 1250122 7641 pif 1 , and the projecting end 34c of the inner seal portion 34 is in a state of being movable inward in the radial direction. Further, the end side mold 4 is raised with respect to the inner surface side mold 2 to be separated from the TE ring portion 39 and the ear protectors. Next, as shown in Fig. 6, all of the inner surface side molds 2 (the inner surface side mold main body 5 and the outer cylinder member 6) are moved upward relative to the lid 31. A thinned concave portion forming convex portion 12a having an inner diameter at least smaller than the maximum outer diameter of the inner seal portion 34 is formed on the inner circumference of the inner seal portion forming notch 12, and is thinned when the main body 5 and the outer tubular member 6 are moved upward. The concave portion forming convex portion 12a applies an upward force to the inner seal portion 34 (the thinned concave portion 34a lower edge portion 34f). Referring to Fig. 7, at this time, the inner seal portion 34 is elastically deformed so that the vicinity of the front end portion of the inner seal portion 34 moves inward, and the outer diameter of the inner seal portion 34 is reduced. Thus, the thinned concave portion forming the convex portion 12a allows the contact convex portion 34b of the inner seal portion 34 to pass smoothly. Therefore, when the inner surface side mold 2 is pulled out, the thinned concave portion forming convex portion 12a exerts an appropriate force on the inner side seal portion 34. Further, in this process, the outer cylinder member also applies an upward force to the ear protector 41, and the end side mold 4 has been separated from the TE ring portion 39 and the ear protector 41, and the ear protector 41 is elastically folded upward. The state of deformation. Therefore, the outer cylinder member 6 does not exert an excessive force on the ear protector 41 when the inner surface side mold 2 is pulled out. After the above-described drawing process, the inner side mold is taken out by the lid 31 as shown in Fig. 8, and the finished lid 31 is obtained. The lid 31 is rotated in the container opening 邰 toward the occluding direction ‘ by the insect entanglement of the 盍 31 and the male screw of the container opening, so that the lid 31 is attached to the container opening 16 1250122 7641 pif 1 . At this time, the inner seal portion 34 is fitted into the inside of the container opening portion, and the contact convex portion 34b is brought into contact with the inner wall of the container opening portion without gap contact to seal the container opening portion. When the plug is opened, the cover 31 is rotated in the opening direction, the rise of the Te ring portion 39 is blocked, and the main body 38 continues to rise, so that the TE ring portion 39 is separated from the main body 38 by the cutting of the bridge portion 37, that is, The inner seal portion 34 can be pulled out of the container opening to release the seal. The cover 31 of the preferred embodiment has a top plate portion 32 and a cylindrical portion 33' suspended from the periphery thereof, and an annular inner seal portion 34 is formed on the inner surface of the top plate portion 32, and is formed at the base end of the inner seal portion 34. A thin portion 35 which is thinner than the other portions is formed in the vicinity, and the tortuous rigidity of the inner seal portion 34 of this portion is set to be low, so that the inner seal portion 34 has complete flexibility. Therefore, when the cover 31 is attached to the opening of the container, the inner seal portion 34 can easily correspond to the inner surface shape of the opening portion of the container, and is bent and deformed by the thin portion 35 to press the container opening with a certain pressure in the peripheral direction. The inner faces of the parts are in contact. For example, when one portion of the container opening 形成 in the peripheral direction is formed thinner than the other portions, the vicinity of the front end of the inner seal portion 34 is changed toward the thin-walled portion of the container opening portion by the bending deformation of the thin portion 35. . Therefore, the pressing force corresponding to the inner surface of the inner portion of the inner sealing portion 34 of the thin portion is stable, and at the same time, the pressure drop corresponding to the portion other than the thin portion can be suppressed. The inner seal portion 34 can be brought into contact with the inner surface of the opening portion of the container at a constant pressure throughout the circumference. In this way, even in the case of the container having the dimensional variability, it is possible to prevent the opening of the opening pressure of the 17 1250122 7641 pif 1 due to the excessive pressure of the inner surface of the opening portion of the inner sealing portion 34, thereby opening the plug. The torque is maintained at the set threshold. Further, the pressing force corresponding to the inner surface of the container opening portion of the inner seal portion 34 is prevented from becoming unstable, and the sealing property corresponding to the container opening portion of the inner seal portion 34 can be improved, and the sealing performance of the lid 31 can be improved. Further, the thin portion 35 is formed to form a thinned concave portion 34a on the outer circumference of the inner seal portion 34, and a contact convex portion that protrudes outward from the vicinity of the proximal end portion is formed in the lower portion (near the front end portion) of the inner seal portion 34. 34b. Therefore, when the cover 31 is mounted, the lower portion of the inner seal portion 34 (near the front end portion) can seal the container opening portion, and when the lid 31 is opened, the sealing state of the φ container can be delayed, thereby improving the damage. . The manufacturing method of the above preferred embodiment is such that the inner surface side mold 2 is pulled out from the formed cover 31, and the outer tube member 6 and the inner surface side mold body 5 reach the protruding end 34c of the inner side seal portion 34 toward the inner side. After the position of the square movement, the inner side mold 2 can be pulled out by the cover 31. In the process of pulling out, the thinned concave portion forming convex portion 12a formed at the notch 12 applies an upward force to the inner seal portion 34, and at this time, the vicinity of the front end portion of the inner seal portion 34 moves inward, thereby The outer diameter of the inner seal portion 34 is reduced. Therefore, the thinned concave portion forming convex portion 12a having an inner diameter smaller than the maximum outer diameter of the inner seal portion 34 is formed on the outer tubular member 6, and the inner surface seal portion 34 can be formed when the inner surface side mold 2 is pulled out. Apply appropriate force to pull out smoothly. Therefore, it is possible to prevent the occurrence of a phenomenon such as formation of an abnormal protruding portion such as a concave portion, breakage of a crack or the like, stretching deformation, or breakage in the inner seal portion 34. Therefore, it is possible to prevent deformation of the inner seal portion 34 (for example, formation of an abnormal protruding portion) due to excessive partial pressing force of the inner seal portion 34 corresponding to the inner surface of the opening portion of the container, so that the opening torque is maintained at the set After that. 18 1250122 7641 pif 1 Moreover, when the dimensional precision of the inner seal portion 34 is increased, it is possible to prevent the inner seal portion 34 from being deformed or damaged (for example, cracked) between the inner seal portion 34 and the inner surface of the container opening portion. The gap, which in turn, results in a cover 31 having excellent sealing properties. In the manufacturing apparatus 1 of the above-described embodiment, the inner surface side mold 2 includes an inner surface side mold body 5 having a top cover portion 9 that cuts the inner surface shape of the inner seal portion 34, and an inner surface shape that fits the inner seal. The outer portion of the portion 34 has a shape other than the tubular member 6. And the outer cylinder member 6 and the inner surface side mold main body 5 can be relatively moved in the up and down direction along the protruding direction of the inner side seal portion 34 to pull the inner side mold 2 out of the formed cover 31 as the outer cylinder After the member 6 and the inner-side mold main body 5 are located at positions where the protruding end 34c of the inner seal portion 34 is movable inward, the inner-side mold 2 can be pulled out from the lid 31. Therefore, the inner surface side mold 2 can be smoothly pulled out without applying an excessive force to the inner side seal portion 34, and formation of an abnormal protruding portion such as a concave portion or a breakage such as a crack in the inner seal portion 34 can be prevented. , stretching deformation, fracture and other phenomena. Therefore, deformation or breakage of the inner seal portion 34 due to excessive partial pressing force of the inner seal portion 34 corresponding to the inner surface of the opening portion of the container can be prevented, and generation between the inner seal portion 34 and the inner surface of the container opening portion can be prevented. The gap is such that the opening torque can be maintained at the set threshold and the sealing performance is improved. In the present invention, the thinned concave portion formed in the inner seal portion disclosed in the above embodiment is not limited. For example, the thinned concave portion as shown by the symbol 44a in Fig. 9 is formed to have a certain inclination angle. Lower edge portion 44f. Further, as shown in the reference numeral 54a of Fig. 10, the thinned concave portion may have a cross-sectional shape which is curved inwardly. Further, in the above embodiment, the thin portion of the inner seal portion is formed to be thinned, and the recess portion is not limited thereto. As shown in Fig. 11, the thinned concave portion 64a formed on the inner circumference of the inner end portion of the inner side seal portion 34 may be added to the structure of the lid 31. Further, reference numerals 45, 55, and 65 in Figs. 9 to 11 denote thin-walled portions. Further, in the present invention, the formation position of the thinned concave portion may be formed on the inner circumference of the inner seal portion. INDUSTRIAL APPLICABILITY The synthetic resin cover of the present invention has a top plate portion and a tubular portion that is suspended from the periphery thereof, and an annular inner seal portion that protrudes on the inner surface of the top plate portion, and φ is formed on the inner seal portion. A thin portion which is thinner than the other portions is formed near the end, and the tortuous rigidity of the inner seal portion of this portion is set to be low, so that the inner seal portion has complete flexibility. Therefore, when the lid is attached to the opening of the container, the inner seal portion can be easily bent and deformed in accordance with the shape of the inner surface of the opening portion of the container, and can be brought into contact with the inner surface of the opening portion of the container at a constant pressing force in the peripheral direction. Therefore, even in the case of a container having dimensional variability, it is possible to prevent the local pressing force corresponding to the inner surface of the opening portion of the inner sealing portion from being excessively large, and to make the profitable beach red. * It also prevents gaps between the inner seal and the container opening to improve the sealing performance. Further, in the method for producing a synthetic resin cap according to the present invention, the inner surface side mold is pulled out by the formed lid, and the protruding end of the outer tube member and the inner surface side mold body reaching the inner side seal portion is movable inwardly. After the position, the inner side mold can be pulled out by the cover, and the inner side mold can be smoothly pulled out without applying excessive force to the inner seal portion. Therefore, it is possible to prevent the occurrence of breakage, stretch deformation, breakage, and the like in the formation of the abnormal protrusions 20 1250122 7641 pif 1 such as the concave portion or the like in the inner seal portion. Therefore, it is possible to prevent deformation or breakage of the inner seal portion due to excessive partial pressing force of the inner seal portion corresponding to the inner surface of the opening portion of the container, and to prevent a gap from being formed between the inner seal portion and the inner surface of the container opening portion. The opening torque can be maintained at the set threshold and the sealing performance is improved.
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