JP3952142B2 - Injection molded body - Google Patents

Description

又は一般式（２）：
【化６】

で表される化合物が好ましい。一般式（１）と（２）において、Ｒ¹およびＲ²はそれぞれ独立して、炭素数が１〜１０の脂肪族基、炭素数が３〜１０の脂環式基、及び炭素数が６〜１０の芳香族基からなる群から選ばれる有機基、好ましくは、メチレン基、エチレン基、プロピレン基、ブチレン基又はこれらの構造異性体、例えば、イソプロピレン基、イソブチレン基を表す。Ｒ³は炭素数が１〜１０の脂肪族基、炭素数が３〜１０の脂環式基、及び炭素数が６〜１０の芳香族基からなる群から選ばれる有機基、好ましくは、メチル基、エチル基、プロピル基、ブチル基、又はこれらの構造異性体、例えば、イソプロピル基、イソブチル基を表す。一般式（１）及び（２）の化合物としては、３，９−ビス（１，１−ジメチル−２−ヒドロキシエチル）−２，４，８，１０−テトラオキサスピロ〔５．５〕ウンデカン、５−メチロール−５−エチル−２−（１，１−ジメチル−２−ヒドロキシエチル）−１，３−ジオキサン等が特に好ましい。
【００１３】
環状アセタール骨格を有するジカルボン酸としては、一般式（３）：
【化７】

又は一般式（４）：
【化８】

で表される化合物が好ましい。一般式（３）及び（４）において、Ｒ³は前記と同様であり、Ｒ⁴及びＲ⁵はそれぞれ独立して炭素数が１〜１０の脂肪族基、炭素数が３〜１０の脂環式基、及び炭素数が６〜１０の芳香族基からなる群から選ばれる有機基、好ましくは、メチレン基、エチレン基、プロピレン基、ブチレン基又はこれらの構造異性体、例えば、イソプロピレン基、イソブチレン基を表す。Ｒ⁶およびＲ⁷はそれぞれ独立して水素原子、メチル基、エチル基、又はイソプロピル基、好ましくは水素原子あるいはメチル基を表す。一般式（３）及び（４）の化合物としては、３，９−ビス（１，１−ジメチル−２−カルボキシエチル）−２，４，８，１０−テトラオキサスピロ〔５．５〕ウンデカン、５−カルボキシ−５−エチル−２−（１，１−ジメチル−２−カルボキシエチル）−１，３−ジオキサン等が特に好ましい。
【００１４】
本発明に用いられるポリエステル樹脂は、環状アセタール骨格を有するジカルボン酸単位及び／又は環状アセタール骨格を有するジオール単位を導入することにより、ガラス転移温度が上昇する。これにより、射出成形体の耐熱性が向上する。また、同時にポリエステル樹脂の結晶性を低下させる。これにより、射出成形体の厚みが増した場合にも、成形時の余熱で結晶化が進行し、成形体が白化することを防ぐことができる。
【００１５】
本発明に用いられるポリエステル樹脂の環状アセタール骨格を有するジオール単位、又は環状アセタール骨格を有するジカルボン酸単位の含有割合は、それぞれジオール構成単位、ジカルボン酸構成単位の１〜５０モル％であり、好ましくは１０〜４０モル％、更に好ましくは１５〜３０モル％である。上記割合とすることで、射出成形体に透明性、耐衝撃性、耐熱性を付与することができる。
【００１６】
本発明に用いられる環状アセタール骨格を有するジオール以外のジオールとしては、特に制限はされないが、エチレングリコール、トリメチレングリコール、１，４−ブタンジオール、１，５−ペンタンジオール、１，６−ヘキサンジオール、ジエチレングリコール、プロピレングリコール、ネオペンチルグリコール等の脂肪族ジオール類；ポリエチレングリコール、ポリプロピレングリコール、ポリブチレングリコール等のポリエーテル化合物類；１，３−シクロヘキサンジメタノール、１，４−シクロヘキサンジメタノール、１，２−デカヒドロナフタレンジメタノール、１，３−デカヒドロナフタレンジメタノール、１，４−デカヒドロナフタレンジメタノール、１，５−デカヒドロナフタレンジメタノール、１，６−デカヒドロナフタレンジメタノール、２，７−デカヒドロナフタレンジメタノール、テトラリンジメタノール、ノルボルネンジメタノール、トリシクロデカンジメタノール、ペンタシクロドデカンジメタノール等の脂環式ジオール類；４，４’−（１−メチルエチリデン）ビスフェノール、メチレンビスフェノール（ビスフェノールＦ）、４，４’−シクロヘキシリデンビスフェノール（ビスフェノールＺ）、４，４’−スルホニルビスフェノール（ビスフェノールＳ）等のビスフェノール類；前記ビスフェノール類のアルキレンオキシド付加物；ヒドロキノン、レゾルシン、４，４’−ジヒドロキシビフェニル、４，４’−ジヒドロキシジフェニルエーテル、４，４’−ジヒドロキシジフェニルベンゾフェノン等の芳香族ジヒドロキシ化合物；及び前記芳香族ジヒドロキシ化合物のアルキレンオキシド付加物等が例示できる。
【００１７】
本発明において、環状アセタール骨格を有するジオール以外のジオールとして、炭素数２〜１０のアルキレンジオールをジオール構成単位の５０〜９９モル％を構成するように用いるのが好ましい。炭素数２〜１０のアルキレンジオールとしては、特に制限は無いが、エチレングリコール、トリメチレングリコール、１，４−ブタンジオール、１，５−ペンタンジオール、１，６−ヘキサンジオール、ジエチレングリコール、プロピレングリコール、ネオペンチルグリコール等の脂肪族ジオール類、１，３−シクロヘキサンジメタノール、１，４−シクロヘキサンジメタノール等の脂環式ジオール類等が例示できる。本発明に用いられるポリエステル樹脂の機械的性能、経済性等の面から特にエチレングリコールが好ましい。ジオール構成単位中に環状アセタール骨格を有するジオールが含まれる場合、ジオール構成単位中のエチレングリコール単位の割合は、好ましくは５０〜９９モル％、より好ましくは６０〜９９モル％、特に好ましくは７０〜９９モル％とすることで上記効果は一層顕著になる。尚、ジオール構成単位中に環状アセタール骨格を有するジオールが含まれない場合のエチレングリコール単位の割合は、５０モル％以上である。
【００１８】
本発明に用いられる環状アセタール骨格を有するジカルボン酸以外のジカルボン酸としては、特に制限はされないが、コハク酸、グルタル酸、アジピン酸、ピメリン酸、スベリン酸、アゼライン酸、セバシン酸、デカンジカルボン酸、ドデカンジカルボン酸、シクロヘキサンジカルボン酸、ノルボルナンジカルボン酸、トリシクロデカンジカルボン酸、ペンタシクロドデカンジカルボン酸等の脂肪族ジカルボン酸及びこれらのエステル形成性誘導体；テレフタル酸、イソフタル酸、フタル酸、２−メチルテレフタル酸、１，４−ナフタレンジカルボン酸、１，５−ナフタレンジカルボン酸、２，６−ナフタレンジカルボン酸、２，７−ナフタレンジカルボン酸、ビフェニルジカルボン酸、テトラリンジカルボン酸等の芳香族ジカルボン酸及びこれらのエステル形成性誘導体が例示できる。本発明に用いられるポリエステル樹脂の機械的性能の面から芳香族ジカルボン酸及びこのエステル形成性誘導体が好ましく、特にテレフタル酸、イソフタル酸、２，６−ナフタレンジカルボン酸及びこれらのエステル形成性誘導体が好ましい。ジカルボン酸構成単位中に環状アセタール骨格を有するジカルボン酸が含まれる場合、ジカルボン酸構成単位中の占める芳香族ジカルボン酸単位の割合は、好ましくは５０〜９９モル％、より好ましくは７０〜９９モル％である。尚、ジカルボン酸構成単位中に環状アセタール骨格を有するジカルボン酸が含まれない場合の芳香族ジカルボン酸単位の割合は、５０モル％以上である。上記割合とすることにより、本発明に用いられるポリエステル樹脂は耐熱性、機械的性能がより優れたものとなる。
【００１９】
本発明に用いられるポリエステル樹脂のガラス転移温度は９０℃以上である。ガラス転移温度を９０℃以上とすることで、射出成形体に耐熱性を付与することができる。
【００２０】
本発明に用いられるポリエステル樹脂の降温時の結晶化発熱ピークの熱量は４Ｊ／ｇ以下である。降温時の結晶化発熱ピークの熱量を４Ｊ／ｇ以下とすることで、射出成形体の厚みが増した場合にも、成形時の余熱で結晶化が進行し、成形体が白化することを防ぐことができる。
【００２１】
本発明に用いられるポリエステル樹脂の極限粘度（フェノールと１，１，２，２−テトラクロロエタンとの質量比が６：４の混合溶媒中２５℃で測定）は好ましくは０．３〜１．５ｄｌ／ｇの範囲であり、より好ましくは０．５〜１．２ｄｌ／ｇ、更に好ましくは０．６〜１．０ｄｌ／ｇの範囲である。上記範囲とすることで射出成形体に良好な成形性と十分な強度を付与することができる。
【００２２】
本発明に用いられるポリエステル樹脂には本発明の目的を損なわない範囲でブチルアルコール、ヘキシルアルコール、オクチルアルコール等のモノアルコール類やトリメチロールプロパン、グリセリン、ペンタエリスリトール等の３価以上の多価アルコール、安息香酸、プロピオン酸、酪酸等のモノカルボン酸を原料モノマーとして用いることもできる。
【００２３】
更に用途に応じて各種の成形助剤や添加剤、例えばフィラー、着色剤、補強剤、表面平滑剤、レベリング剤、硬化反応促進剤、光安定化剤、紫外線吸収剤、可塑剤、酸化防止剤、増量剤、つや消し剤、乾燥調節剤、帯電防止剤、沈降防止剤、界面活性剤、流れ改良剤、乾燥油、ワックス類、熱可塑性オリゴマー等を含むこともできる。
【００２４】
本発明で用いられるポリエステル樹脂を製造する方法に特に制限はなく、従来公知の方法を適用することが出来る。例えばエステル交換法、直接エステル化法等の溶融重合法または溶液重合法を挙げることが出来る。エステル交換触媒、エステル化触媒、エーテル化防止剤、また重合に用いる重合触媒、熱安定剤、光安定剤等の各種安定剤、重合調整剤等も従来既知のものを用いることが出来る。エステル交換触媒として、マンガン、コバルト、亜鉛、チタン、カルシウム等の化合物、またエステル化触媒として、マンガン、コバルト、亜鉛、チタン、カルシウム等の化合物、またエーテル化防止剤としてアミン化合物等が例示される。重縮合触媒としてはゲルマニウム、アンチモン、スズ、チタン等の化合物が例示される。また熱安定剤としてリン酸、亜リン酸、フェニルホスホン酸等の各種リン化合物を加えることも有効である。その他光安定剤、耐電防止剤、滑剤、酸化防止剤、離型剤等を加えても良い。また、直接エステル化法において、スラリー性改善のために水を加えても良い。
【００２５】
本発明の射出成形体を得る方法としては特に制限されるものでは無く、従来公知の方法を用いることができる。例えば、ポリエステル樹脂を射出成形機に供給し、ポリエステル樹脂の溶融温度においてポリエステル樹脂を所定形状の金型に射出し、金型内で冷却固化することにより成形体を得る方法が挙げられる。
【００２６】
本発明の射出成形体は肉厚３ｍｍの部分のヘーズが３％以下であり、且つ、全光線透過率が８７％以上である。上記範囲とすることにより、射出成形体の透明性と外観が良好となる。肉厚３ｍｍの部分のヘーズが３％を超えたり、全光線透過率が８７％未満であると、射出成形体の透明性が損なわれ、外観が不良となる。
【００２７】
本発明の射出成形体は肉厚３ｍｍの部分にＲ２０の錘により５００Ｊの衝撃エネルギーを垂直に与えた際の落錘衝撃破断強度が３０ｋＪ／ｍ以上である。落錘衝撃破断強度が３０ｋＪ／ｍ以上であることにより、耐衝撃性が良好となる。
【００２８】
本発明の射出成形体は曲げ応力４５１ｋＰａ時の荷重たわみ温度が７５℃以上である。荷重たわみ温度が７５℃以上であることにより、耐熱性が良好となる。
【００２９】
【実施例】
以下に、実施例を挙げて本発明を更に詳しく説明するが、本発明はこれらの実施例によりその範囲を限定されるものではない。
【００３０】
樹脂の評価
（１）極限粘度
混合溶媒（質量比：フェノール／１，１，２，２−テトラクロロエタン＝６／４）を用いて２５℃恒温下で測定した。
（２）ガラス転移温度、降温時結晶化発熱ピーク
ポリエステル樹脂のガラス転移温度（Ｔｇｍ）は島津製作所製ＤＳＣ／ＴＡ−５０ＷＳを使用し、試料約１０ｍｇをアルミニウム製非密封容器に入れ、窒素ガス（３０ｍｌ／ｍｉｎ）気流中昇温速度２０℃／ｍｉｎで測定し、ＤＳＣ曲線の転移前後における基線の差の１／２だけ変化した温度をガラス転移温度とした。また降温時結晶化発熱ピーク（以下「ΔＨｃ」という）とは、上記Ｔｇを測定後２８０℃で１分間保持した後、１０℃／ｍｉｎの降温速度で降温した際に現れる発熱ピークの面積から求めた値である。
【００３１】
１．射出成形体の評価
（１）ヘーズ、全光線透過率
３ｍｍ厚の射出成形体を、ＪＩＳ−Ｋ−７１０５、ＡＳＴＭ Ｄ１００３に準じて測定した。測定装置は、日本電色工業社製の曇価測定装置（型式：ＣＯＨ−３００Ａ）を使用した。
（２）落錘衝撃試験
３ｍｍ厚の射出成形体に錘を落下させた際の落錘衝撃破断強度を測定した。錘の形状はＲ２０、衝撃エネルギーは５００Ｊで、ＰＡＲＫＥＲ ＣＯＲＰＯＲＡＴＩＯＮ社製 落錘衝撃測定試験機により測定を行った。
（３）荷重たわみ温度
ＡＳＴＭ Ｄ６４８に準じた。試験片に加える曲げ応力は４５１ｋＰａで行った。
【００３２】
実施例１〜２、参考例１〜４、比較例１〜４
［樹脂の合成］充填塔式精留塔、分縮器、全縮器、コールドトラップ、攪拌翼、加熱装置、窒素導入管を備えた１５０リットル（Ｌ）のポリエステル製造装置に表１〜３に記載の量のモノマーを仕込み、酢酸マンガン四水和物をジカルボン酸成分に対して０．０３モル％加え、常圧、窒素雰囲気下で昇温した。２００℃まで昇温し、エステル交換反応を行った。ジカルボン酸成分の反応転化率を９０モル％以上とした後、ジカルボン酸成分に対して０．０２モル％の三酸化アンチモンと０．０６モル％のリン酸トリメチルを加え、昇温と減圧を徐々に行い、最終的に２７０〜３００℃、０．１ｋＰａ以下で重縮合反応を行った。徐々に反応物の粘度が上昇し、適度な溶融粘度になった時点で反応を終了し、ポリエステル樹脂を得た。
【００３３】
射出成形体の作製
得られたポリエステル樹脂を射出成形機（ＦＡＮＵＣ製ファナックＡＳ１００Ｂ）により、シリンダー温度２４０〜２８０℃、金型温度３５℃の条件で、厚さ約３ｍｍの成形品を作製した。
結果を表１〜３に示す。
【００３４】
尚、表中の略記の意味は下記の通りである。
ＤＭＴ：テレフタル酸ジメチル
ＤＭＩ：イソフタル酸ジメチル
ＮＤＣＭ：２，６−ナフタレンジカルボン酸ジメチル
ＳＰＤ：３，９−ビス（１，１−ジメチル−２−カルボキシエチル）−２，４，８，１０−テトラオキサスピロ〔５，５〕ウンデカン
ＤＯＤ：５−カルボキシ−５−エチル−２−（１，１−ジメチル−２−カルボキシキシエチル）−１，３−ジオキサン
ＥＧ：エチレングリコール
ＳＰＧ：３，９−ビス（１，１−ジメチル−２−ヒドロキシエチル）２，４，８，１０−テトラオキサスピロ〔５，５〕ウンデカン
ＤＯＧ：５−メチロール−５−エチル−２−（１，１−ジメチル−２−ヒドロキシエチル）−１，３−ジオキサン
ＣＨＤＭ：１，４−シクロヘキサンジメタノール
【００３５】
表１
参考例番号 参考例１ 参考例２ 参考例３ 参考例４
モノマー仕込量（モル）
ジカルボン酸成分
ＤＭＴ ２４９．３ ２１６．６ ２７７．３ ２０５．７
ＤＭＩ − − − ２２．９
ジオール成分
ＥＧ ３９８．９ ３５７．４ ４４３．６ ４６８．６
ＳＰＧ ４９．９ ７５．８ ２７．７ −
ＤＯＧ − − − １０２．９
ポリエステル樹脂の評価
Ｔｇ（℃） ９６ １０４ ９０ ９２
ＩＶ（ｄｌ／ｇ） ０．７２ ０．７３ ０．６７ ０．７６
ΔＨｃ（Ｊ／ｇ） ０ ０ ２ ０
射出成形体の評価
ＨＡＺＥ（％） １．１ ０．６ １．８ ０．５
全光線透過率（％） ８８ ８９ ８８ ９０
落錘衝撃破断強度（ｋＪ／ｍ）
４８ ４９ ４６ ３２
荷重たわみ温度（℃） ８２ ９３ ７９ ８０
【００３６】
表２
実施例番号 実施例１ 実施例２
モノマー仕込量（モル）
ジカルボン酸成分
ＤＭＴ １８９．５ １１５．３
ＮＤＣＭ ５４．１ １１５．３
ＳＰＤ ２７．１ −
ＤＯＤ − ２５．６
ジオール成分
ＥＧ ４６０．３ ４３５．７
ポリエステル樹脂の評価
Ｔｇ（℃） ９０ １０４
ＩＶ（ｄｌ／ｇ） ０．７０ ０．６８
ΔＨｃ（Ｊ／ｇ） ０ ０
射出成形体の評価
ヘーズ（％） １．７ ０．７
全光線透過率（％） ８８ ８８
落錘衝撃破断強度（ｋＪ／ｍ） ４１ ５１
荷重たわみ温度（℃） ８１ ９２
【００３７】

【００３８】
【発明の効果】
本発明で用いられる樹脂から得られる射出成形体は透明性、耐衝撃性、耐熱性など優れた性能を兼ね備えており本発明の工業的意義は大きい。[0001]
BACKGROUND OF THE INVENTION
In the present invention, the main component is a diol having a cyclic acetal skeleton and / or a dicarboxylic acid having a cyclic acetal skeleton, an aromatic dicarboxylic acid, and a polyester resin copolymerized with an alkylene diol having 2 to 10 carbon atoms. The present invention relates to an injection molded article having good impact resistance and heat resistance.
[0002]
[Prior art]
Polyester resins are used for fibers, films, sheet molded products, injection molded products, and the like because of their mechanical and chemical properties. In particular, polyethylene terephthalate (hereinafter sometimes abbreviated as PET) is widely used for fibers, films, sheet molded articles, injection molded articles, and the like from the viewpoints of performance and economy. Containers made by PET injection molding have been adopted as an alternative material for glass containers because they have good transparency and hygiene and can impart impact resistance and light weight compared to glass containers.
[0003]
However, since PET has high crystallinity, the thickness of the injection molded body increases, and when cooling during molding becomes insufficient, whitening due to crystallization proceeds due to residual heat during molding. Furthermore, this crystallization has a problem that impact resistance is lowered.
[0004]
In order to solve these problems, Japanese Patent Application Laid-Open No. 11-158260 discloses a problem of whitening of a molded product by reducing crystallinity by copolymerizing PET with isophthalic acid or increasing the degree of polymerization of PET. However, the impact resistance of the injection molded product obtained from the copolymerized PET is not improved.
[0005]
In order to improve transparency and impact resistance, 1,3-propanediol (Japanese Patent Laid-Open No. 2001-253938) or 2-methyl-1,3-propanediol (Japanese Patent Laid-Open No. 2001-220434) is added to PET. However, these resins have a problem that their glass transition temperature is low and their heat resistance is impaired.
[0006]
In addition, it has been proposed to reduce crystallinity and improve transparency and impact resistance by copolymerizing diethylene glycol or 1,4-cyclohexanedimethanol with PET. The injection molded product obtained had a problem that the heat resistance was impaired, for example, Tg was decreased by copolymerizing diethylene glycol, or the deflection temperature under load was decreased by copolymerizing 1,4-cyclohexanedimethanol.
[0007]
Thus, a polyester-based injection molded article having transparency, impact resistance, and heat resistance has not been proposed so far.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide a polyester-based injection-molded article having transparency, impact resistance and heat resistance in view of the above-mentioned problems of the prior art.
[0009]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above-mentioned object, the present inventors have jointly used a diol having a cyclic acetal skeleton and / or a dicarboxylic acid having a cyclic acetal skeleton, an aromatic dicarboxylic acid, and an alkylene diol having 2 to 10 carbon atoms. The present inventors have found that an injection-molded product obtained from a polymerized polyester resin has excellent transparency, impact resistance, and heat resistance, and reached the present invention.
[0010]
That is, the present invention has a dicarboxylic acid constituent unit containing 1 to 50 mol% of a dicarboxylic acid unit having a cyclic acetal skeleton and / or a diol constituent unit containing 1 to 50 mol% of a diol unit having a cyclic acetal skeleton, 50 to 99 mol% of the acid constituent units are aromatic dicarboxylic acid units, 50 to 99 mol% of the diol constituent units are alkylene diol units having 2 to 10 carbon atoms, phenol, 1,1,2,2- The intrinsic viscosity measured at 25 ° C. in a mixed solvent having a mass ratio of 6: 4 with tetrachloroethane at 25 ° C. is 0.3 to 1.5 dl / g, the glass transition temperature measured by a differential scanning calorimeter is 90 ° C. or higher, and the temperature is lowered Provided is an injection molded article using a polyester resin having a calorific value at the time of crystallization exothermic peak of 4 J / g or less.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The polyester resin used in the present invention has a dicarboxylic acid structural unit and / or a cyclic acetal skeleton containing 1 to 50 mol% of a dicarboxylic acid unit having a cyclic acetal skeleton (a structural unit derived from a dicarboxylic acid having a cyclic acetal skeleton). It is a polyester resin containing a diol constituent unit containing 1 to 50 mol% of a diol unit (a constituent unit derived from a diol having a cyclic acetal skeleton), an aromatic dicarboxylic acid unit, and an alkylene diol unit having 2 to 10 carbon atoms. . The dicarboxylic acid constitutional unit is an aliphatic dicarboxylic acid unit, the diol constitutional unit is a polyether compound, alicyclic diol, bisphenol, alkylene oxide adduct of bisphenol, aromatic dihydroxy compound, aromatic dihydroxy compound described later. A structural unit derived from an alkylene oxide adduct or the like may further be included.
[0012]
The diol having a cyclic acetal skeleton used in the present invention is represented by the general formula (1):
[Chemical formula 5]

Or general formula (2):
[Chemical 6]

The compound represented by these is preferable. In the general formulas (1) and (2), R¹And R²Are each independently an organic group selected from the group consisting of an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms, Represents a methylene group, an ethylene group, a propylene group, a butylene group or a structural isomer thereof, for example, an isopropylene group or an isobutylene group. R^ThreeIs an organic group selected from the group consisting of an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms, preferably a methyl group, It represents an ethyl group, a propyl group, a butyl group, or a structural isomer thereof such as isopropyl group or isobutyl group. Examples of the compounds of the general formulas (1) and (2) include 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, 5-methylol-5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -1,3-dioxane and the like are particularly preferable.
[0013]
As the dicarboxylic acid having a cyclic acetal skeleton, the general formula (3):
[Chemical 7]

Or general formula (4):
[Chemical 8]

The compound represented by these is preferable. In the general formulas (3) and (4), R^ThreeIs the same as above, R^FourAnd R^FiveAre each independently an organic group selected from the group consisting of an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms, Represents a methylene group, an ethylene group, a propylene group, a butylene group or a structural isomer thereof, for example, an isopropylene group or an isobutylene group. R⁶And R⁷Each independently represents a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group, preferably a hydrogen atom or a methyl group. As compounds of the general formulas (3) and (4), 3,9-bis (1,1-dimethyl-2-carboxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, 5-carboxy-5-ethyl-2- (1,1-dimethyl-2-carboxyethyl) -1,3-dioxane and the like are particularly preferable.
[0014]
The polyester resin used in the present invention increases the glass transition temperature by introducing a dicarboxylic acid unit having a cyclic acetal skeleton and / or a diol unit having a cyclic acetal skeleton. Thereby, the heat resistance of the injection molded body is improved. At the same time, the crystallinity of the polyester resin is lowered. Thereby, even when the thickness of the injection molded body is increased, it is possible to prevent crystallization from proceeding due to residual heat during molding and whitening of the molded body.
[0015]
The content ratio of the diol unit having a cyclic acetal skeleton of the polyester resin used in the present invention or the dicarboxylic acid unit having a cyclic acetal skeleton is 1 to 50 mol% of the diol structural unit and the dicarboxylic acid structural unit, respectively. It is 10-40 mol%, More preferably, it is 15-30 mol%. By setting it as the said ratio, transparency, impact resistance, and heat resistance can be provided to an injection molded object.
[0016]
The diol other than the diol having a cyclic acetal skeleton used in the present invention is not particularly limited, but ethylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol. Aliphatic diols such as diethylene glycol, propylene glycol and neopentyl glycol; polyether compounds such as polyethylene glycol, polypropylene glycol and polybutylene glycol; 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1, 2-decahydronaphthalene diethanol, 1,3-decahydronaphthalene diethanol, 1,4-decahydronaphthalene diethanol, 1,5-decahydronaphthalene diethanol, 1,6-decahydronaphth Cycloaliphatic diols such as range methanol, 2,7-decahydronaphthalene diethanol, tetralin dimethanol, norbornene dimethanol, tricyclodecane dimethanol, pentacyclododecane dimethanol; 4,4 ′-(1-methylethylidene ) Bisphenols such as bisphenol, methylene bisphenol (bisphenol F), 4,4′-cyclohexylidene bisphenol (bisphenol Z), 4,4′-sulfonyl bisphenol (bisphenol S); alkylene oxide adducts of the bisphenols; hydroquinone And aromatic dihydroxy compounds such as resorcin, 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenylbenzophenone; Alkylene oxide adducts of group dihydroxy compounds can be exemplified.
[0017]
In the present invention, an alkylene diol having 2 to 10 carbon atoms is preferably used as a diol other than the diol having a cyclic acetal skeleton so as to constitute 50 to 99 mol% of the diol structural unit. The alkylene diol having 2 to 10 carbon atoms is not particularly limited, but ethylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, propylene glycol, Examples include aliphatic diols such as neopentyl glycol, and alicyclic diols such as 1,3-cyclohexanedimethanol and 1,4-cyclohexanedimethanol. Ethylene glycol is particularly preferred from the standpoints of mechanical performance and economy of the polyester resin used in the present invention. When a diol having a cyclic acetal skeleton is included in the diol constituent unit, the proportion of the ethylene glycol unit in the diol constituent unit is preferably 50 to 99 mol%, more preferably 60 to 99 mol%, and particularly preferably 70 to 99 mol%. By making it 99 mol%, the above effect becomes more remarkable. In addition, the ratio of the ethylene glycol unit when the diol having a cyclic acetal skeleton is not included in the diol constituent unit is 50 mol% or more.
[0018]
The dicarboxylic acid other than the dicarboxylic acid having a cyclic acetal skeleton used in the present invention is not particularly limited, but succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, Aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, cyclohexanedicarboxylic acid, norbornanedicarboxylic acid, tricyclodecanedicarboxylic acid, pentacyclododecanedicarboxylic acid and ester-forming derivatives thereof; terephthalic acid, isophthalic acid, phthalic acid, 2-methylterephthalic acid Aromatic dicarboxylic acids such as acids, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetralindicarboxylic acid, and the like These ester-forming derivatives can be exemplified. Aromatic dicarboxylic acids and ester-forming derivatives thereof are preferred from the viewpoint of mechanical performance of the polyester resin used in the present invention, and terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and ester-forming derivatives thereof are particularly preferred. . When a dicarboxylic acid having a cyclic acetal skeleton is contained in the dicarboxylic acid structural unit, the proportion of the aromatic dicarboxylic acid unit in the dicarboxylic acid structural unit is preferably 50 to 99 mol%, more preferably 70 to 99 mol%. It is. In addition, the ratio of the aromatic dicarboxylic acid unit when the dicarboxylic acid having a cyclic acetal skeleton is not included in the dicarboxylic acid structural unit is 50 mol% or more. By setting it as the said ratio, the polyester resin used for this invention becomes a thing excellent in heat resistance and mechanical performance.
[0019]
The glass transition temperature of the polyester resin used in the present invention is 90 ° C. or higher. By setting the glass transition temperature to 90 ° C. or higher, heat resistance can be imparted to the injection molded article.
[0020]
The amount of heat of the crystallization exothermic peak when the temperature of the polyester resin used in the present invention is lowered is 4 J / g or less. By controlling the amount of heat of the crystallization exothermic peak at the time of cooling to 4 J / g or less, even when the thickness of the injection molded body is increased, crystallization proceeds with residual heat at the time of molding to prevent the molded body from being whitened. be able to.
[0021]
The intrinsic viscosity of the polyester resin used in the present invention (measured at 25 ° C. in a mixed solvent having a mass ratio of phenol and 1,1,2,2-tetrachloroethane of 6: 4) is preferably 0.3 to 1.5 dl. / G, more preferably 0.5 to 1.2 dl / g, still more preferably 0.6 to 1.0 dl / g. By setting it as the above range, good moldability and sufficient strength can be imparted to the injection molded article.
[0022]
In the polyester resin used in the present invention, monoalcohols such as butyl alcohol, hexyl alcohol and octyl alcohol and trihydric or higher polyhydric alcohols such as trimethylolpropane, glycerin and pentaerythritol, as long as the object of the present invention is not impaired. Monocarboxylic acids such as benzoic acid, propionic acid and butyric acid can also be used as raw material monomers.
[0023]
Furthermore, various molding aids and additives such as fillers, colorants, reinforcing agents, surface smoothing agents, leveling agents, curing reaction accelerators, light stabilizers, ultraviolet absorbers, plasticizers, antioxidants depending on applications. , Extenders, matting agents, drying regulators, antistatic agents, antisettling agents, surfactants, flow improvers, drying oils, waxes, thermoplastic oligomers, and the like.
[0024]
There is no restriction | limiting in particular in the method of manufacturing the polyester resin used by this invention, A conventionally well-known method is applicable. Examples thereof include a melt polymerization method such as a transesterification method and a direct esterification method, or a solution polymerization method. As the transesterification catalyst, esterification catalyst, etherification inhibitor, polymerization catalyst used in the polymerization, various stabilizers such as a heat stabilizer and a light stabilizer, polymerization regulators and the like, conventionally known ones can be used. Examples of the transesterification catalyst include compounds such as manganese, cobalt, zinc, titanium and calcium; examples of the esterification catalyst include compounds such as manganese, cobalt, zinc, titanium and calcium; and examples of the etherification inhibitor include amine compounds. . Examples of the polycondensation catalyst include compounds such as germanium, antimony, tin, and titanium. It is also effective to add various phosphorus compounds such as phosphoric acid, phosphorous acid, and phenylphosphonic acid as a heat stabilizer. In addition, a light stabilizer, an antistatic agent, a lubricant, an antioxidant, a release agent, and the like may be added. In the direct esterification method, water may be added to improve the slurry property.
[0025]
The method for obtaining the injection-molded product of the present invention is not particularly limited, and conventionally known methods can be used. For example, there is a method of obtaining a molded body by supplying a polyester resin to an injection molding machine, injecting the polyester resin into a mold having a predetermined shape at the melting temperature of the polyester resin, and cooling and solidifying in the mold.
[0026]
The injection-molded article of the present invention has a haze of 3% or less and a total light transmittance of 87% or more in a portion having a thickness of 3 mm. By setting it as the said range, the transparency and external appearance of an injection molded object become favorable. If the haze of the portion having a thickness of 3 mm exceeds 3% or the total light transmittance is less than 87%, the transparency of the injection-molded product is impaired and the appearance becomes poor.
[0027]
The injection molded article of the present invention has a falling weight impact breaking strength of 30 kJ / m or more when an impact energy of 500 J is vertically applied to a 3 mm thick portion by an R20 weight. When the falling weight impact breaking strength is 30 kJ / m or more, the impact resistance is improved.
[0028]
The injection molded product of the present invention has a deflection temperature under load of 451 kPa at a bending stress of 75 ° C. or higher. When the deflection temperature under load is 75 ° C. or higher, the heat resistance is improved.
[0029]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited by these examples.
[0030]
Resin evaluation
(1) Intrinsic viscosity
It measured under 25 degreeC constant temperature using the mixed solvent (mass ratio: phenol / 1,1,2,2-tetrachloroethane = 6/4).
(2) Glass transition temperature, crystallization exothermic peak during cooling
The glass transition temperature (Tgm) of the polyester resin is DSC / TA-50WS manufactured by Shimadzu Corporation. About 10 mg of a sample is put in an aluminum non-sealed container, and the temperature rising rate in a nitrogen gas (30 ml / min) airflow is 20 ° C./min. The temperature at which the difference between the baselines before and after the transition of the DSC curve changed by 1/2 was taken as the glass transition temperature. The crystallization exothermic peak at the time of temperature decrease (hereinafter referred to as “ΔHc”) is obtained from the area of the exothermic peak that appears when the Tg is measured and held at 280 ° C. for 1 minute and then cooled at a temperature decrease rate of 10 ° C./min. Value.
[0031]
1. Evaluation of injection molded products
(1) Haze, total light transmittance
A 3 mm-thick injection molded article was measured in accordance with JIS-K-7105 and ASTM D1003. As the measuring device, a cloudiness value measuring device (model: COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd. was used.
(2) Drop weight impact test
The falling weight impact breaking strength was measured when the weight was dropped onto an injection molded body having a thickness of 3 mm. The weight was R20, the impact energy was 500 J, and the measurement was performed with a falling weight impact measuring tester manufactured by PARKER CORPORATION.
(3) Deflection temperature under load
According to ASTM D648. The bending stress applied to the test piece was 451 kPa.
[0032]
Example 12,Reference Examples 1-4Comparative Examples 1-4
[Synthesis of Resin] Tables 1 to 3 are provided in a 150 liter (L) polyester production apparatus equipped with a packed tower type rectification tower, a partial condenser, a full condenser, a cold trap, a stirring blade, a heating device, and a nitrogen introduction pipe. The monomer in the amount described was charged, manganese acetate tetrahydrate was added in an amount of 0.03 mol% based on the dicarboxylic acid component, and the temperature was raised under normal pressure and a nitrogen atmosphere. The temperature was raised to 200 ° C. to conduct a transesterification reaction. After the reaction conversion rate of the dicarboxylic acid component is 90 mol% or more, 0.02 mol% of antimony trioxide and 0.06 mol% of trimethyl phosphate are added to the dicarboxylic acid component, and the temperature and pressure are gradually increased. Finally, a polycondensation reaction was performed at 270 to 300 ° C. and 0.1 kPa or less. When the viscosity of the reaction product gradually increased and reached an appropriate melt viscosity, the reaction was terminated to obtain a polyester resin.
[0033]
Production of injection molded body
Using the obtained polyester resin, a molded product having a thickness of about 3 mm was produced by an injection molding machine (FANUC FANUC AS100B) under conditions of a cylinder temperature of 240 to 280 ° C. and a mold temperature of 35 ° C.
The results are shown in Tables 1-3.
[0034]
In addition, the meaning of the abbreviation in a table | surface is as follows.
DMT: dimethyl terephthalate
DMI: Dimethyl isophthalate
NDCM: Dimethyl 2,6-naphthalenedicarboxylate
SPD: 3,9-bis (1,1-dimethyl-2-carboxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane
DOD: 5-carboxy-5-ethyl-2- (1,1-dimethyl-2-carboxyxyethyl) -1,3-dioxane
EG: Ethylene glycol
SPG: 3,9-bis (1,1-dimethyl-2-hydroxyethyl) 2,4,8,10-tetraoxaspiro [5,5] undecane
DOG: 5-methylol-5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -1,3-dioxane
CHDM: 1,4-cyclohexanedimethanol
[0035]
Table 1
Reference example number Reference example 1 Reference example 2 Reference example 3 Reference example 4
Monomer charge (mole)
Dicarboxylic acid component
DMT 249.3 216.6 277.3 205.7
DMI---22.9
Diol component
EG 398.9 357.4 443.6 468.6
SPG 49.9 75.8 27.7-
DOG---102.9
Evaluation of polyester resin
Tg (° C.) 96 104 90 92
IV (dl / g) 0.72 0.73 0.67 0.76
ΔHc (J / g) 0 0 2 0
Evaluation of injection molded products
HAZE (%) 1.1 0.6 1.8 0.5
Total light transmittance (%) 88 89 88 90
Drop weight impact breaking strength (kJ / m)
                    48 49 46 32
Deflection temperature under load (℃) 82 93 79 80
[0036]
Table 2
Example No. Example 1 Example 2
Monomer charge (mole)
Dicarboxylic acid component
DMT 189.5 115.3
NDCM 54.1 115.3
SPD 27.1 −
DOD-25.6
Diol component
EG 460.3 435.7
Evaluation of polyester resin
Tg (° C.) 90 104
IV (dl / g) 0.70 0.68
ΔHc (J / g) 0 0
Evaluation of injection molded products
Haze (%) 1.7 0.7
Total light transmittance (%) 88 88
Drop weight impact breaking strength (kJ / m) 41 51
Deflection temperature under load (℃) 81 92
[0037]

[0038]
【The invention's effect】
The injection molded product obtained from the resin used in the present invention has excellent performance such as transparency, impact resistance, and heat resistance, and the industrial significance of the present invention is great.

Claims (5)

It has a dicarboxylic acid structural unit containing 1 to 50 mol% of a unit derived from a dicarboxylic acid having a cyclic acetal skeleton represented by the following general formula (3) or general formula (4), and is 50 mol% of the dicarboxylic acid structural unit The above is a unit derived from an aromatic dicarboxylic acid , 50 mol% or more of the diol structural unit is a unit derived from an alkylene diol having 2 to 10 carbon atoms, phenol, 1,1,2,2-tetrachloroethane, The intrinsic viscosity measured at 25 ° C. in a mixed solvent of 6: 4 mass ratio is 0.3 to 1.5 dl / g, the glass transition temperature measured with a differential scanning calorimeter is 90 ° C. or higher, and the crystallization is performed when the temperature is lowered. An injection molded article using a polyester resin having an exothermic peak with a heat quantity of 4 J / g or less.

Wherein R4 and R5 are each independently a group consisting of an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms. R6 and R7 each independently represents a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group) or the general formula (4):

(In the formula, R 3 represents an organic group selected from the group consisting of an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms. , R4, R6 and R7 are as defined above.) The injection-molded article according to claim 1 or 2, wherein The dicarboxylic acid having a cyclic acetal skeleton is 3,9-bis (1,1-dimethyl-2-carboxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane or 5-carboxy-5 The injection-molded article according to claim 1, which is -ethyl-2- (1,1-dimethyl-2-carboxyethyl) -1,3-dioxane. Aromatic dicarboxylic acids, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and an injection molded article according to claim 1 or 2 is at least one compound selected from the group consisting of ester-forming derivatives thereof . The alkylene diol is ethylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, propylene glycol, neopentyl glycol, 1,3-cyclohexanedimethanol, and 1 , 4-cyclohexane claims 1 is at least one compound selected from the group consisting dimethanol injection molded body according to any one of 3. The injection-molded article according to any one of claims 1 to 4 , which has the following physical properties (1) to (3).
(1) The haze of the portion having a thickness of 3 mm is 3% or less, and the total light transmittance is 87% or more.
(2) The falling weight impact breaking strength is 30 kJ / m or more when the impact energy of 500 J is vertically applied to the 3 mm thick portion by the R20 weight.
(3) The deflection temperature under load when the bending stress is 451 kPa is 75 ° C. or higher.