JP4278749B2 - Refrigerating machine oil composition and lubrication method using the composition - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は冷凍機用潤滑油組成物に関し、さらに詳しくは、ＣＯ2 を主成分をとする冷媒を用いた冷凍機用潤滑油組成物及び該組成物を用いた潤滑方法、特に油分離器及び／又はホットガスラインを有する圧縮式冷凍サイクルにおける潤滑方法に関する。
【０００２】
【従来の技術】
一般に、冷凍機、例えば圧縮機，凝縮器，膨張弁，蒸発器からなる圧縮型冷凍機の圧縮式冷凍サイクルは、冷媒と潤滑油との混合液体がこの密閉された系内を循環する構造となっている。このような圧縮型冷凍機には、冷媒として、従来ジクロロジフルオロメタン（Ｒ−１２）やクロロジフルオロメタン（Ｒ−２２）等のクロロフルオロカーボンが用いられており、また、それと併用する多数の潤滑油が製造され使用されてきた。しかるに、従来冷媒として使用されてきたこれらのフロン化合物は、大気中に放出されたときに、成層圏に存在するオゾン層を破壊するなどの環境汚染をもたらすおそれがあることから、最近、世界的にその使用に対する規制が厳しくなりつつある。そのため、新しい冷媒としてハイドロフルオロカーボンやハイドロクロロフルオロカーボンなどの水素含有フロン化合物が注目されるようになってきた。この水素含有フロン化合物、特に１，１，１，２−テトラフルオロエタン（Ｒ−１３４ａ）で代表されるハイドロフルオロカーボンは、オゾン層を破壊するおそれがないが、大気中での寿命が長いため地球温暖化への影響が懸念され、近年このような問題のない自然系冷媒の使用が考えられてきた。
【０００３】
一方で、炭酸ガスは環境に対して無害であり、人に対する安全性という観点では優れたものであり、更に、▲１▼経済的に最適水準に近い圧力、▲２▼従来の冷媒に比べ、非常に小さい圧力比、▲３▼通常のオイルと機械の構造材料に対して優れた適合性、▲４▼いたる場所で簡単に入手可能、▲５▼回収不要で非常に安価である、などの利点を有しており、従来から冷凍機などの冷媒として通常使用されてきたものである。しかしながら、このような炭酸ガスを冷媒として使用した場合、冷凍機の潤滑油として、従来一般的に使用されている潤滑油で潤滑すると潤滑性に劣り、耐摩耗性が不充分となり、その結果安定性が悪くなり長期の安定使用ができなくなる。更に、炭酸ガスを用いた系では、Ｒ−１３４ａなどを用いた系に比べ吐出圧が高く、その結果潤滑油の粘度が低下し、系のシール性が悪化するという問題も生じていた。
【０００４】
【発明が解決しようとする課題】
本発明は、上記観点からなされたもので、ＣＯ2 を主成分とする冷媒を用いた圧縮式冷凍サイクルにおいて、潤滑性能及びシール性が良好で、長期の安定使用が可能な冷凍機油組成物及び該組成物を用いた潤滑方法を提供することを目的とするものである。
【０００５】
【課題を解決するための手段】
本発明者は、鋭意研究を重ねた結果、基油の主成分として特定のエステル油を使用することにより、上記本発明の目的を効果的に達成しうることを見出し本発明を完成したものである。すなわち、本発明は、
（１）ＣＯ2 を主成分とする冷媒と潤滑油組成物とからなり、該潤滑油組成物が、エステル油を主成分とし、４０℃における動粘度が５６〜１３０ｍｍ2 ／ｓである基油を含有し、該エステル油が、ペンタエリスリトールと炭素数８及び／又は炭素数９の脂肪酸とのエステル化合物、及び／又は炭酸エステル化合物である冷凍機油組成物、及び
（２）油分離器及び／又はホットガスラインを有する圧縮式冷凍サイクルにおいて、ＣＯ2 を主成分とする冷媒と潤滑油組成物とからなり、該潤滑油組成物が、エステル油を主成分とし、４０℃における動粘度が５６〜１３０ｍｍ2 ／ｓである基油を含有し、該エステル油が、ペンタエリスリトールと炭素数８及び／又は炭素数９の脂肪酸とのエステル化合物、及び／又は炭酸エステル化合物である冷凍機油組成物を用いることを特徴とする潤滑方法を提供するものである。
【０００６】
【発明の実施の形態】
以下に、本発明の実施の形態を説明する。
本発明の冷凍機油組成物は、ＣＯ2 を主成分とする冷媒と潤滑油組成物とからなり、該潤滑油組成物が、エステル油を主成分とし、４０℃における動粘度が５６〜１３０ｍｍ2 ／ｓである基油を含有し、該エステル油が、ペンタエリスリトールと炭素数８及び／又は炭素数９の脂肪酸とのエステル化合物、及び／又は炭酸エステル化合物である。本発明に用いられるＣＯ2 を主成分とする冷媒としては、ＣＯ2 をそのまま使用する場合のほか、これを炭化水素、Ｒ−１３４ａ等のフッ化炭化水素（あるいは塩化フッ化炭化水素）、エーテルなどの冷媒等と混合したものを使用することができる。
【０００７】
本発明を構成する潤滑油組成物の基油の粘度は、４０℃における動粘度が５６〜１３０ｍｍ2 ／ｓのものが使用される。４０℃における動粘度が５６〜１３０ｍｍ2 ／ｓ、特に７０〜１２０ｍｍ2 ／ｓであることが、圧縮機の効率、潤滑性の点から好ましい。
該基油の主成分であるエステル油としては、▲１▼ペンタエリスリトールと炭素数８及び／又は炭素数９の脂肪酸とのエステル化合物、▲２▼炭酸エステル及びそれらの混合物を挙げることができる。順に説明する。
【０００８】
▲１▼ペンタエリスリトールのエステル化合物
炭素数８及び９の脂肪酸は、直鎖状でもよいし、分岐鎖状でもよい。また、飽和脂肪酸でもよいし、不飽和脂肪酸でもよいが飽和脂肪酸の方が好ましい。炭素数８の脂肪酸は一種でもよいし二種以上でもよい。炭素数９の脂肪酸も一種でもよいし二種以上でもよい。さらに、炭素数８の脂肪酸と９の脂肪酸の混合酸がよく、中でも分岐鎖状の混合酸が好ましい。その場合、炭素数８の脂肪酸と炭素数９の脂肪酸の割合は、モル分率で９０：１０〜１０：９０の範囲で選択できる。炭素数８の好ましい脂肪酸として、オクタン酸、イソオクタン酸、２−エチルヘキサン酸などを挙げることができる。炭素数９の好ましい脂肪酸として、ノナン酸、イソノナン酸、２−エチルヘプタン酸、３，３，５−トリメチルヘキサン酸などを挙げることができる。
【０００９】
なお、ペンタエリスリトールと上記脂肪酸との部分エステルも使用できる。
また、ペンタエリスリトールと炭素数８及び／又は炭素数９の脂肪酸との部分エステルと、脂肪族二塩基酸又は芳香族二塩基酸とのコンプレックスエステルをも使用することができる。その場合の脂肪族二塩基酸としては、コハク酸，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，ウンデカン二酸，ドデカン二酸，トリデカン二酸，ドコサンナ二酸を挙げることができ、芳香族二塩基酸としてフタル酸，イソフタル酸を挙げることができる。コンプレックスエステルを調製するためのエステル化反応は、まず多価アルコールと二塩基酸とを所定の割合で反応させて部分エステル化し、次いでその部分エステルと脂肪酸とを反応させてもよいし、また二塩基酸と脂肪酸の反応順序を逆にしてもよく、また二塩基酸と脂肪酸を混合してエステル化に供してもよい。
【００１０】
▲２▼炭酸エステル
炭酸エステルとしては、下記一般式（Ｉ）
【００１１】
【化１】
（式中、Ｒ1 は炭素数２〜１０のアルキル基、Ｒ2 は炭素数２〜１０のアルキレン基又はシクロアルキレン基、ａは１〜４の整数を示す。）
で表される化合物、又は下記一般式（II）
【００１３】
【化２】
（式中、Ｒ3 は炭素数２〜６の水酸基を有する多価アルコール残基、Ｒ4 は炭素数２〜１０のアルキル基、ｂは２〜６の整数を示す。）
で表される化合物を挙げることができる。上記の炭酸エステルは、ジメチルカーボネートとアルコール類を塩基性触媒の存在下でのエステル交換反応により調製される。
また、下記一般式（III)
【００１５】
【化３】
（式中、Ｒ5 は炭素数１〜１０のアルキル基、Ｒ6 は炭素数２〜１０のアルキル基を示し、ｃは２〜１０の整数、ｄは２〜１００の整数を示し、−ＡＯ−は−ＣＨ2 −ＣＨ（ＣＨ3 ）−Ｏ−、又は−ＣＨ2 −ＣＨ2 −Ｏ−を示す。）
で表される化合物も使用できる。この炭酸エステルは、例えば炭酸とアルキレンオキシドとを反応させて得られるものであるが、そのアルキレンオキシドの付加形態は、エチレンオキサイド単独又はプロピレンオキサイド単独でもよく、混合体でもよい。
【００１７】
上記の▲１▼▲２▼のエステル油は、同種のエステル油を一種又は二種以上を混合して使用してもよいし、▲１▼と▲２▼のエステル油を混合して使用してもよい。なお、基油の粘度について４０℃における動粘度を前述のように５６〜１３０ｍｍ2 ／ｓに調節する必要がある。該エステル油を基油に使用する際、その粘度の範囲をはずれた場合には、他の成分で添加して調節すればよい。粘度が高い場合には、例えば、脂肪族多価アルコールと炭素数３〜９の脂肪酸のエステル油で、１００℃における動粘度が６ｍｍ2 ／ｓ以下のものを適宜添加して適正範囲に調整することができる。また、粘度が低い場合には、ポリマー類を添加して粘度を調節するとよい。該ポリマーは１００℃における動粘度が１０ｍｍ2 ／ｓ以上のものが好ましい。
【００１８】
このようなポリマーとしては、ポリアルキルメタクリレート（例えば、アルキル基が１〜８のもの）、ポリアルキレングリコール（例えば、ポリプロピレングリコール，ポリプロピレングリコール成分とポリエチレングリコール成分からなる共重合体，ポリプロピレングリコール成分とポリブチレングリコール成分からなる共重合体等），ネオペンチルグリコールと脂肪族ジカルボン酸とのポリエステルで、下記式（IV）
【００１９】
【化４】
（ｅは１〜２０の整数を示し、ｆは１〜１０の整数を示す。）
で表されるもの等を挙げることができる。
なお、上記のエステル油を主成分として含む基油は、油分１０重量％（冷媒９０重量％）の二層分離温度（高温側）を通常５℃以上のものを使用すればがよい。好ましくは１０℃以上、更に好ましくは１５℃以上のものを使用すればよい。この温度は実機系内の油と冷媒との相溶性を示すもので、潤滑性にも大いに関係する。
【００２１】
本発明の冷凍機油組成物を構成する潤滑油組成物においては、基油に必要に応じ公知の各種の添加剤、例えばトリクレジルホスフェート（ＴＣＰ），ジオレイルハイドロゲンホスファイト，２−エチルヘキシルジフェニルホスファイト，トリブチルホスファイトなどの極圧剤；フェニルグリシジルエーテル，シクロヘキセンオキシド，α−オレフィンオキサイドなどの酸捕捉剤；フェノール系，アミン系の酸化防止剤；ベンゾトリアゾールやその誘導体などの銅不活性化剤；シリコーン油やフッ化シリコーン油などの消泡剤などを適宜配合することができる。更に、清浄分散剤，粘度指数向上剤，油性剤，防錆剤，腐食防止剤，流動点降下剤等を所望に応じて添加することができる。これらの添加剤は、通常潤滑油組成物中に、０．５〜１０重量％の量で含有される。
【００２２】
本発明においては、前記ＣＯ2 冷媒と潤滑油組成物の使用量については、冷媒／潤滑油組成物の重量比で９９／１〜１０／９０の範囲にあることが好ましい。冷媒の量が上記範囲より少ない場合は冷凍能力の低下が見られ、また上記範囲よりも多い場合は潤滑性能が低下し好ましくない。このような観点から、冷媒／潤滑油組成物の重量比は、９５／５〜３０／７０の範囲にあることが更に好ましい。
【００２３】
本発明の冷凍機油組成物は、種々の冷凍機に使用可能であるが、特に、圧縮型冷凍機の圧縮式冷凍サイクルに好ましく適用できる。とりわけ、本発明の冷凍機油組成物は、例えば添付図１〜３の各々で示されるような油分離器及び／又はホットガスラインを有する圧縮式冷凍サイクルに適用する場合にその効果を有効に奏する。通常、圧縮式冷凍サイクルは、圧縮機−凝縮機−膨張弁−蒸発器からなる。また、冷凍機用の潤滑油は、一般に、冷凍機に使用される冷媒と相溶性が良好なものが使用される。しかし、上記の冷凍サイクルで炭酸ガスを主成分とする冷媒を用いたときに、冷凍機を一般に使用されている潤滑油で潤滑すると、耐摩耗性が不十分であったり、安定性が不足して長期安定使用ができなかった。特に、電気冷蔵庫や小型エアコンディショナーなどの冷凍サイクルのように、膨張弁としてキャピラリーチューブを使用する場合にこの傾向が著しい。そこで、本発明の潤滑方法は、油分離器及び／又はホットガスラインを有する圧縮式冷凍サイクルを炭酸ガスを主成分とする冷媒を使用して運転する場合に、潤滑油組成物として、４０℃の動粘度が５６〜１３０ｍｍ2 ／ｓの前記基油を含有する組成物を用いることを特徴とするものである。
【００２４】
【実施例】
次に、本発明を実施例によりさらに具体的に説明するが、本発明はこれらの例によってなんら限定されるものではない。
実施例１〜９及び比較例１〜３
第１表に示す性状の基油を用いて下記の方法で各試験を行い評価を行った。結果を第２表に示す。
【００２５】
なお、基油の性状及び性能は、次の方法に従って求めた。
（１）溶解性
油１００ｇに５０ｋｇ／ｃｍ2 の加圧条件で炭酸ガスを吹き込み、油中における炭酸ガスの溶解量（重量％）を測定した。
（２）二層分離温度（高温側）
試料油０．２ｇ、冷媒（炭酸ガス）１．８ｇをガラスチューブに入れ封管した。−１０℃より１℃／分割合で加熱し高温側での二層分離温度を求めた。
【００２６】
（３）シールドチューブ試験
ガラス管に触媒Ｆｅ／Ｃｕ／Ａｌを入れ、炭酸ガス／油／水＝０．５ｇ／４ｇ／０．０２ｇの割合で試料を充填し封管した。１７５℃で１０日間保持した後、油外観、触媒外観、全酸価及びスラッジの有無を評価した。
（４）吸湿性試験
油１０ｇを湿度８５％Ｒ．Ｈ．（３０℃）にて１２０時間放置した後の吸湿量（重量％）を求めた。
（５）ファレックス焼付試験
ファレックス試験機を用い、ピン／ブロック材料材料をＡＩＳＩＣ１１３７／ＳＡＥ３１３５とした。ピン／ブロックをセットし、試験容器内に試料の油２００ｇを入れ炭酸ガスを５リットル／ｈで吹き込んだ後、回転数２９０ｒｐｍ、油温５０℃で焼付荷重を測定した。
【００２７】
【表１】
【表２】
実施例１０〜１４及び比較例４〜６
第１表に示した基油に、基油に対して１重量％のトリクレジルホスフェート（ＴＣＰ）及び１．５重量％のα−オレフィンオキサイド（実施例１０，１１）、１．５重量％のフェニルグリシジルエーテル（実施例１２〜１４及び比較例４〜６）を添加した潤滑油組成物について下記の方法で実機テストを行い評価を行った。結果を第３表に示す。
【００３０】
なお、潤滑油組成物についての実機テストは、下記に示す圧縮式冷凍サイクルを用いて行った。
圧縮式冷凍サイクルの方式
Ａ：油分離器を有する「圧縮機−凝縮器−膨張弁−蒸発器」の圧縮式冷凍サイクル（図２参照）
なお、膨張弁はキャピラリーチューブ式のものを使用した。
【００３１】
実機テストは、出力１００ＷのＡの冷凍機について、冷媒として炭酸ガスを用い、炭酸ガス７０重量％、潤滑油組成物３０重量％の割合で下記条件で１年間に亘って冷凍試験を実施した。
運転状況
吸入温度 ： ０℃
吐出温度 ： １００℃
凝縮器出口温度 ： １０℃
評価法
運転状態に異常が生じた時点で停止し、その原因追求のため各部を観察した。
【００３２】
【表３】
【発明の効果】
本発明によれば、ＣＯ2 を主成分とする冷媒を用いた圧縮式冷凍サイクルにおいて、潤滑性能及びシール性が良好で、長期の安定使用が可能な冷凍機油組成物及び該組成物を用いた潤滑方法を提供することができる。
【図面の簡単な説明】
【図１】油分離器及びホットガスラインを有する「圧縮機−凝縮器−膨張弁−蒸発器」の圧縮式冷凍サイクルの一例を示す流れ図である。
【図２】油分離器を有する「圧縮機−凝縮器−膨張弁−蒸発器」の圧縮式冷凍サイクルの一例を示す流れ図である。
【図３】ホットガスラインを有する「圧縮機−凝縮器−膨張弁−蒸発器」の圧縮式冷凍サイクルの一例を示す流れ図である。
【図４】「圧縮機−凝縮器−膨張弁−蒸発器」の圧縮式冷凍サイクルの一例を示す流れ図である。
【符号の説明】
１：圧縮機
２：凝縮器
３：膨張弁
４：蒸発器
５：油分離器
６：ホットガスライン
７：ホットガスライン用弁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lubricating oil composition for a refrigerator, and more specifically, a lubricating oil composition for a refrigerator using a refrigerant mainly composed of CO 2 and a lubricating method using the composition, particularly an oil separator and The present invention relates to a lubrication method in a compression refrigeration cycle having a hot gas line.
[0002]
[Prior art]
Generally, a compression refrigeration cycle of a refrigerator, for example, a compressor type refrigerator including a compressor, a condenser, an expansion valve, and an evaporator, has a structure in which a mixed liquid of refrigerant and lubricating oil circulates in the sealed system. It has become. In such compression refrigerators, chlorofluorocarbons such as dichlorodifluoromethane (R-12) and chlorodifluoromethane (R-22) are conventionally used as refrigerants, and a number of lubricating oils used in combination therewith. Has been manufactured and used. However, these chlorofluorocarbon compounds, which have been used as refrigerants in the past, may cause environmental pollution such as destruction of the ozone layer existing in the stratosphere when released into the atmosphere. Regulations on its use are becoming stricter. Therefore, hydrogen-containing chlorofluorocarbon compounds such as hydrofluorocarbon and hydrochlorofluorocarbon have attracted attention as new refrigerants. This hydrogen-containing chlorofluorocarbon compound, particularly hydrofluorocarbons represented by 1,1,1,2-tetrafluoroethane (R-134a), has no risk of destroying the ozone layer, but has a long life in the atmosphere. There is concern about the impact on global warming, and in recent years, the use of natural refrigerants without such problems has been considered.
[0003]
On the other hand, carbon dioxide gas is harmless to the environment and is excellent in terms of safety to humans. Furthermore, (1) pressure close to the optimum level economically, (2) compared with conventional refrigerants, Very small pressure ratio, (3) excellent compatibility with ordinary oil and machine structural materials, (4) easily available everywhere, (5) very inexpensive and no collection required It has advantages and has been conventionally used as a refrigerant for refrigerators and the like. However, when such a carbon dioxide gas is used as a refrigerant, if it is lubricated with a conventionally used lubricating oil as a lubricating oil for a refrigerator, the lubricity is inferior and the wear resistance becomes insufficient, resulting in a stable It becomes difficult to use for a long time. Further, the system using carbon dioxide gas has a higher discharge pressure than the system using R-134a, resulting in a problem that the viscosity of the lubricating oil is lowered and the sealing performance of the system is deteriorated.
[0004]
[Problems to be solved by the invention]
The present invention has been made from the above viewpoint, and in a compression refrigeration cycle using a refrigerant mainly composed of CO 2 , a refrigerating machine oil composition having good lubrication performance and sealability and capable of long-term stable use, and It is an object of the present invention to provide a lubricating method using the composition.
[0005]
[Means for Solving the Problems]
As a result of intensive studies, the inventor has found that the object of the present invention can be effectively achieved by using a specific ester oil as the main component of the base oil. is there. That is, the present invention
(1) A base oil comprising a refrigerant mainly composed of CO 2 and a lubricating oil composition, the lubricating oil composition having an ester oil as a main component and a kinematic viscosity at 40 ° C. of 56 to 130 mm 2 / s. A refrigerating machine oil composition, wherein the ester oil is an ester compound of pentaerythritol and a fatty acid having 8 and / or 9 carbon atoms and / or a carbonate compound, and (2) an oil separator and / or Alternatively, in a compression refrigeration cycle having a hot gas line, it comprises a refrigerant mainly composed of CO 2 and a lubricating oil composition. The lubricating oil composition has an ester oil as a main component and a kinematic viscosity at 40 ° C. of 56. A cold oil containing a base oil of ˜130 mm 2 / s, wherein the ester oil is an ester compound of pentaerythritol and a fatty acid having 8 and / or 9 carbon atoms and / or a carbonate compound. The present invention provides a lubricating method characterized by using a refrigerator oil composition.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
The refrigerating machine oil composition of the present invention comprises a refrigerant mainly composed of CO 2 and a lubricating oil composition. The lubricating oil composition has an ester oil as a main component and a kinematic viscosity at 40 ° C. of 56 to 130 mm 2. The base oil is / s, and the ester oil is an ester compound of pentaerythritol and a fatty acid having 8 and / or 9 carbon atoms and / or a carbonate compound. As a refrigerant mainly composed of CO 2 used in the present invention, in addition to the case of using CO 2 as it is, it is used as a hydrocarbon, a fluorinated hydrocarbon such as R-134a (or chlorofluorinated hydrocarbon), an ether. What mixed with refrigerant | coolants, such as these, can be used.
[0007]
The viscosity of the base oil of the lubricating oil composition constituting the present invention is such that the kinematic viscosity at 40 ° C. is 56 to 130 mm 2 / s. A kinematic viscosity at 40 ° C. of 56 to 130 mm 2 / s, particularly 70 to 120 mm 2 / s, is preferable from the viewpoint of compressor efficiency and lubricity.
Examples of the ester oil that is the main component of the base oil include (1) ester compounds of pentaerythritol and fatty acids having 8 and / or 9 carbon atoms, and (2) carbonate esters and mixtures thereof. These will be described in order.
[0008]
(1) Ester compound of pentaerythritol The fatty acid having 8 and 9 carbon atoms may be linear or branched. Saturated fatty acids or unsaturated fatty acids may be used, but saturated fatty acids are preferred. The fatty acid having 8 carbon atoms may be one kind or two or more kinds. The fatty acid having 9 carbon atoms may be one kind or two or more kinds. Furthermore, a mixed acid of a fatty acid having 8 carbon atoms and a fatty acid having 9 carbon atoms is preferable, and a branched mixed acid is particularly preferable. In that case, the ratio of the fatty acid having 8 carbon atoms and the fatty acid having 9 carbon atoms can be selected in the range of 90:10 to 10:90 in terms of molar fraction. Preferred fatty acids having 8 carbon atoms include octanoic acid, isooctanoic acid, 2-ethylhexanoic acid and the like. Preferred examples of the fatty acid having 9 carbon atoms include nonanoic acid, isononanoic acid, 2-ethylheptanoic acid, 3,3,5-trimethylhexanoic acid, and the like.
[0009]
A partial ester of pentaerythritol and the above fatty acid can also be used.
In addition, a complex ester of a partial ester of pentaerythritol and a fatty acid having 8 and / or 9 carbon atoms and an aliphatic dibasic acid or an aromatic dibasic acid can also be used. Examples of the aliphatic dibasic acid in that case include succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, docosannadioic acid, Examples of aromatic dibasic acids include phthalic acid and isophthalic acid. The esterification reaction for preparing the complex ester may be carried out by first reacting a polyhydric alcohol and a dibasic acid at a predetermined ratio to form a partial ester, and then reacting the partial ester with a fatty acid. The reaction order of the basic acid and the fatty acid may be reversed, or the dibasic acid and the fatty acid may be mixed and used for esterification.
[0010]
(2) Carbonate ester As the carbonate ester, the following general formula (I)
[0011]
[Chemical 1]
(Wherein R 1 represents an alkyl group having 2 to 10 carbon atoms, R 2 represents an alkylene group or cycloalkylene group having 2 to 10 carbon atoms, and a represents an integer of 1 to 4)
Or a compound represented by the following general formula (II)
[0013]
[Chemical formula 2]
(In the formula, R 3 represents a polyhydric alcohol residue having a hydroxyl group having 2 to 6 carbon atoms, R 4 represents an alkyl group having 2 to 10 carbon atoms, and b represents an integer of 2 to 6).
The compound represented by these can be mentioned. The carbonate ester is prepared by transesterification of dimethyl carbonate and alcohol in the presence of a basic catalyst.
In addition, the following general formula (III)
[0015]
[Chemical 3]
(In the formula, R 5 represents an alkyl group having 1 to 10 carbon atoms, R 6 represents an alkyl group having 2 to 10 carbon atoms, c represents an integer of 2 to 10, d represents an integer of 2 to 100, and —AO - is -CH 2 -CH (CH 3) -O- , or -CH 2 shows a -CH 2 -O-).
The compound represented by these can also be used. The carbonate ester is obtained, for example, by reacting carbonic acid with alkylene oxide. The addition form of the alkylene oxide may be ethylene oxide alone, propylene oxide alone, or a mixture.
[0017]
The above (1) and (2) ester oils may be used singly or in combination of two or more, and (1) and (2) ester oils may be used in combination. May be. In addition, it is necessary to adjust the kinematic viscosity in 40 degreeC about the viscosity of a base oil to 56-130 mm < 2 > / s as mentioned above. When the ester oil is used as a base oil, it may be adjusted by adding other components when the viscosity range is out of the range. When the viscosity is high, for example, an ester oil of an aliphatic polyhydric alcohol and a fatty acid having 3 to 9 carbon atoms and a kinematic viscosity at 100 ° C. of 6 mm 2 / s or less is appropriately added to adjust to an appropriate range. be able to. When the viscosity is low, the viscosity may be adjusted by adding polymers. The polymer preferably has a kinematic viscosity at 100 ° C. of 10 mm 2 / s or more.
[0018]
Examples of such polymers include polyalkyl methacrylates (for example, those having an alkyl group of 1 to 8), polyalkylene glycols (for example, polypropylene glycol, a copolymer comprising a polypropylene glycol component and a polyethylene glycol component, polypropylene glycol component and poly A copolymer of a butylene glycol component), a polyester of neopentyl glycol and an aliphatic dicarboxylic acid, represented by the following formula (IV)
[0019]
[Formula 4]
(E represents an integer of 1 to 20, and f represents an integer of 1 to 10.)
The thing etc. which are represented by can be mentioned.
In addition, what is necessary is just to use the base oil which contains said ester oil as a main component what is 5 degreeC or more normally for the two-layer separation temperature (high temperature side) of oil content 10weight% (refrigerant 90weight%). It is preferable to use one having a temperature of 10 ° C. or higher, more preferably 15 ° C. or higher. This temperature indicates the compatibility of the oil and refrigerant in the actual system, and is greatly related to the lubricity.
[0021]
In the lubricating oil composition constituting the refrigerating machine oil composition of the present invention, various known additives such as tricresyl phosphate (TCP), dioleyl hydrogen phosphite, 2-ethylhexyl diphenyl phosphine are added to the base oil as necessary. Extreme pressure agents such as phyte and tributyl phosphite; acid scavengers such as phenyl glycidyl ether, cyclohexene oxide and α-olefin oxide; phenol-based and amine-based antioxidants; copper deactivators such as benzotriazole and its derivatives An antifoaming agent such as silicone oil or fluorinated silicone oil can be appropriately blended. Furthermore, detergent dispersants, viscosity index improvers, oiliness agents, rust inhibitors, corrosion inhibitors, pour point depressants, and the like can be added as desired. These additives are usually contained in the lubricating oil composition in an amount of 0.5 to 10% by weight.
[0022]
In the present invention, the use amount of the CO 2 refrigerant and the lubricating oil composition is preferably in the range of 99/1 to 10/90 by weight ratio of the refrigerant / lubricating oil composition. When the amount of the refrigerant is less than the above range, the refrigerating capacity is lowered, and when it is more than the above range, the lubricating performance is lowered, which is not preferable. From such a viewpoint, the weight ratio of the refrigerant / lubricating oil composition is more preferably in the range of 95/5 to 30/70.
[0023]
The refrigerating machine oil composition of the present invention can be used in various refrigerating machines, but can be preferably applied particularly to a compression refrigeration cycle of a compression refrigerating machine. In particular, the refrigerating machine oil composition of the present invention effectively exhibits its effect when applied to, for example, a compression refrigeration cycle having an oil separator and / or a hot gas line as shown in each of FIGS. . Usually, the compression refrigeration cycle consists of a compressor-condenser-expansion valve-evaporator. In addition, as the lubricating oil for the refrigerator, one having good compatibility with the refrigerant used in the refrigerator is generally used. However, when a refrigerant mainly composed of carbon dioxide gas is used in the above refrigeration cycle, if the refrigerator is lubricated with commonly used lubricating oil, the wear resistance is insufficient or the stability is insufficient. Long-term stable use. In particular, this tendency is remarkable when a capillary tube is used as an expansion valve as in a refrigeration cycle such as an electric refrigerator or a small air conditioner. Therefore, the lubrication method of the present invention provides a lubricating oil composition having a temperature of 40 ° C. when a compression refrigeration cycle having an oil separator and / or a hot gas line is operated using a refrigerant mainly composed of carbon dioxide. The composition containing the base oil having a kinematic viscosity of 56 to 130 mm 2 / s is used.
[0024]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these examples.
Examples 1-9 and Comparative Examples 1-3
Each test was performed by the following method using the base oil having the properties shown in Table 1 and evaluated. The results are shown in Table 2.
[0025]
The properties and performance of the base oil were determined according to the following method.
(1) Carbon dioxide gas was blown into 100 g of soluble oil under a pressure of 50 kg / cm 2 , and the amount (% by weight) of carbon dioxide dissolved in the oil was measured.
(2) Two-layer separation temperature (high temperature side)
0.2 g of sample oil and 1.8 g of refrigerant (carbon dioxide gas) were put in a glass tube and sealed. Heating was performed at a rate of 1 ° C./min from −10 ° C., and the two-layer separation temperature on the high temperature side was determined.
[0026]
(3) Shield tube test The catalyst Fe / Cu / Al was put into a glass tube, and the sample was filled at a ratio of carbon dioxide gas / oil / water = 0.5 g / 4 g / 0.02 g and sealed. After holding at 175 ° C. for 10 days, the oil appearance, the catalyst appearance, the total acid value, and the presence or absence of sludge were evaluated.
(4) 10 g of hygroscopic test oil was added to 85% R.H. H. The amount of moisture absorption (% by weight) after standing at (30 ° C.) for 120 hours was determined.
(5) Falex seizure test Using a Falex tester, the pin / block material was AISI 1137 / SAE3135. A pin / block was set, 200 g of sample oil was put into a test container, and carbon dioxide gas was blown at 5 liter / h, and then the baking load was measured at a rotation speed of 290 rpm and an oil temperature of 50 ° C.
[0027]
[Table 1]
[Table 2]
Examples 10-14 and Comparative Examples 4-6
1% by weight of tricresyl phosphate (TCP) and 1.5% by weight of α-olefin oxide (Examples 10 and 11), 1.5% by weight based on the base oil shown in Table 1 The lubricating oil compositions to which the phenyl glycidyl ether (Examples 12 to 14 and Comparative Examples 4 to 6) were added were subjected to actual machine tests and evaluated by the following methods. The results are shown in Table 3.
[0030]
In addition, the actual machine test about a lubricating oil composition was done using the compression-type refrigeration cycle shown below.
Compressive refrigeration cycle system A: "Compressor-condenser-expansion valve-evaporator" compression refrigeration cycle with oil separator (see Fig. 2)
The expansion valve was a capillary tube type.
[0031]
In the actual machine test, a refrigeration test was conducted for a refrigerator with an output of 100 W using carbon dioxide as a refrigerant at a ratio of 70% by weight of carbon dioxide and 30% by weight of a lubricating oil composition for one year under the following conditions.
Operation status <br/> Inhalation temperature: 0 ° C
Discharge temperature: 100 ° C
Condenser outlet temperature: 10 ° C
Evaluation method When an abnormality occurred in the operating state, the vehicle was stopped, and each part was observed to investigate the cause.
[0032]
[Table 3]
【The invention's effect】
According to the present invention, in a compression refrigeration cycle using a refrigerant mainly composed of CO 2 , a refrigerating machine oil composition having good lubrication performance and sealability and capable of long-term stable use and the composition are used. A lubrication method can be provided.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an example of a compression refrigeration cycle of a “compressor-condenser-expansion valve-evaporator” having an oil separator and a hot gas line.
FIG. 2 is a flowchart showing an example of a compression refrigeration cycle of a “compressor-condenser-expansion valve-evaporator” having an oil separator.
FIG. 3 is a flowchart showing an example of a compression refrigeration cycle of a “compressor-condenser-expansion valve-evaporator” having a hot gas line.
FIG. 4 is a flowchart showing an example of a compression refrigeration cycle of “compressor-condenser-expansion valve-evaporator”.
[Explanation of symbols]
1: Compressor 2: Condenser 3: Expansion valve 4: Evaporator 5: Oil separator 6: Hot gas line 7: Hot gas line valve
Claims (4)
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35319398A JP4278749B2 (en) | 1998-12-11 | 1998-12-11 | Refrigerating machine oil composition and lubrication method using the composition |
| TW088116305A TW546371B (en) | 1998-12-11 | 1999-09-22 | Refrigerator oil composition, and method of using the composition for lubrication |
| TW091100682A TW546372B (en) | 1998-12-11 | 1999-09-22 | Refrigerator oil composition, and method of using the composition for lubrication |
| US09/401,261 US6263683B1 (en) | 1998-12-11 | 1999-09-23 | Refrigerator oil composition, and method of using the composition for lubrication |
| EP99119121.4A EP1008643B1 (en) | 1998-12-11 | 1999-10-04 | Refrigerator oil composition, and method of using the composition for lubrication |
| EP10184286A EP2325290A1 (en) | 1998-12-11 | 1999-10-04 | Refrigerator oil composition, and method of using the composition for lubrication |
| KR1019990056660A KR100636941B1 (en) | 1998-12-11 | 1999-12-10 | Refrigerator oil composition, and method of using the composition for lubrication |
| US09/859,465 US6354094B2 (en) | 1998-12-11 | 2001-05-18 | Refrigerator oil composition, and method of using the composition for lubrication |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35319398A JP4278749B2 (en) | 1998-12-11 | 1998-12-11 | Refrigerating machine oil composition and lubrication method using the composition |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2008170801A Division JP5149714B2 (en) | 2008-06-30 | 2008-06-30 | Refrigerator oil composition |
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| JP2000169869A JP2000169869A (en) | 2000-06-20 |
| JP4278749B2 true JP4278749B2 (en) | 2009-06-17 |
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| JP35319398A Expired - Fee Related JP4278749B2 (en) | 1998-12-11 | 1998-12-11 | Refrigerating machine oil composition and lubrication method using the composition |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2008266655A (en) * | 2008-06-30 | 2008-11-06 | Idemitsu Kosan Co Ltd | Refrigerating machine oil composition |
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| CN101018844A (en) * | 2004-09-14 | 2007-08-15 | 出光兴产株式会社 | Refrigerating machine oil composition |
| JP4000337B1 (en) * | 2006-03-23 | 2007-10-31 | 新日本石油株式会社 | Refrigerating machine oil for carbon dioxide refrigerant, Refrigerating machine oil for carbon dioxide refrigerant |
| US8193129B2 (en) | 2006-07-06 | 2012-06-05 | Nippon Oil Corporation | Refrigerator oil, compressor oil composition, hydraulic fluid composition, metalworking fluid composition, heat treatment oil composition, lubricant composition for machine tool and lubricant composition |
| JP5216231B2 (en) * | 2007-03-29 | 2013-06-19 | Ｊｘ日鉱日石エネルギー株式会社 | Working fluid composition for refrigerator |
| JP5068618B2 (en) * | 2007-09-26 | 2012-11-07 | Ｊｘ日鉱日石エネルギー株式会社 | Refrigerating machine oil for carbon dioxide refrigerant and refrigerating machine oil for carbon dioxide refrigerant |
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| JP5143517B2 (en) * | 2007-09-26 | 2013-02-13 | Ｊｘ日鉱日石エネルギー株式会社 | Refrigerating machine oil for carbon dioxide refrigerant and refrigerating machine oil for carbon dioxide refrigerant |
| JP5068619B2 (en) * | 2007-09-26 | 2012-11-07 | Ｊｘ日鉱日石エネルギー株式会社 | Refrigerating machine oil for carbon dioxide refrigerant and refrigerating machine oil for carbon dioxide refrigerant |
| JP5171185B2 (en) * | 2007-09-26 | 2013-03-27 | Ｊｘ日鉱日石エネルギー株式会社 | Refrigerating machine oil for carbon dioxide refrigerant and refrigerating machine oil for carbon dioxide refrigerant |
| CN201972923U (en) | 2007-10-24 | 2011-09-14 | 艾默生环境优化技术有限公司 | Scroll machine |
| JP6493829B2 (en) * | 2014-05-30 | 2019-04-03 | Ｋｈネオケム株式会社 | Esters of pentaerythritol and isotridecanoic acid used therefor |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008266655A (en) * | 2008-06-30 | 2008-11-06 | Idemitsu Kosan Co Ltd | Refrigerating machine oil composition |
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