JP4658295B2 - Cleaning agent for resin molding machine - Google Patents
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- JP4658295B2 JP4658295B2 JP2000252327A JP2000252327A JP4658295B2 JP 4658295 B2 JP4658295 B2 JP 4658295B2 JP 2000252327 A JP2000252327 A JP 2000252327A JP 2000252327 A JP2000252327 A JP 2000252327A JP 4658295 B2 JP4658295 B2 JP 4658295B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、射出成形機、押出成形機などの樹脂成形機の材料変更および色替え作業を効率よく実施するために使用される、樹脂成形機の加熱シリンダーやスクリュー等の洗浄剤に関する。
【０００２】
【従来の技術】
射出成形機や押出成形機などの樹脂成形機は、単一品種を多量に生産できる点で優れており、今まで樹脂材料分野の発展に大きく寄与してきた。ところが、最近ではユーザーの要求が多様化し、樹脂成形品も少量多品種の生産が必要不可欠となってきた。その結果、樹脂成形機の材料変更および色替えの頻度が高くなってきている。例えば、材料変更の作業の中で最も問題となるのが、樹脂成形機の加熱シリンダーおよびスクリューに融着している樹脂材料の洗浄である。
【０００３】
すなわち、加熱シリンダーおよびスクリューを分解して機械的に洗浄する方法は、あまりにも多くの時間と人手を費やすので、通常の作業では採用されていない。一般には、加熱シリンダー内の残留樹脂を、続いて成形する樹脂で洗浄除去する操作が行われている。しかし、このような洗浄操作では、樹脂の交換が不完全であり、しかも洗浄に使用される樹脂の使用量も多くなり不経済である。
【０００４】
そこで従来より、樹脂成形機の樹脂変更等を効率良く行なう為の洗浄剤の検討がなされている。例えば、特開平３−２３０９２２号公報には、２３０℃、１０ｋｇで測定したメルトインデックスが０.０５〜２０ｇ／１０分のメタクリル系重合体からなる洗浄剤が開示されている。また例えば、特開平８−１５５９６９号公報には、熱可塑性樹脂１００質量部に対して熱可塑性超高分子２〜５０質量部が混合された成形機用洗浄剤が開示されている。
【０００５】
また、実際に樹脂成形機用洗浄剤として各種のものが市販されており、それらは高粘度タイプと低粘度タイプに大別される。
【０００６】
【発明が解決しようとする課題】
しかしながら、上述した公報に記載の洗浄剤は、まだ洗浄力が不充分である。また、市販品のうち、高粘度タイプの洗浄剤は加熱シリンダー内に滞留している樹脂の除去には有効であるが、この洗浄剤を引き続き成形する樹脂で除去することが難しく、洗浄剤が成形品に混入してしまい、ブツやシルバーなどの欠陥が発生するという欠点がある。一方、低粘度タイプの洗浄剤は加熱シリンダー内の残留樹脂を完全に除去することが難しく、次に成形した成形品中に混入してしまう。更に、このタイプの洗浄剤には、界面活性剤、発泡剤、可塑剤などが多量に使用されているので、洗浄剤がわずかでも成形品中に混入すると、機械的性質や熱的性質の低下をもたらす。
【０００７】
また、市販品には無機フィラー添加タイプのものが有るが、これは高粘度タイプのものと同様に、加熱シリンダー内に滞留している樹脂の除去には有効であるが、引き続き成形される樹脂で無機フィラーを除去することが難しく、成形品に混入してシルバー状の外観不良が発生するという欠点がある。
【０００８】
本発明の目的は、上述の各従来技術の課題を解決することにあり、具体的には、樹脂成形機の加熱シリンダー内等に残留している樹脂を短時間で効率よく除去することができ、しかも次に成形する樹脂材料によりその洗浄剤を容易に除去できる樹脂成形機用洗浄剤を提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明者らは、上記目的を達成すべく種々研究を実施した結果、メタクリル酸メチルを主成分とする特定の重合体等を特定の組成比で配合した洗浄剤が非常に有効であることを見出し、本発明を完成するに至った。
【００１０】
すなわち本発明は、メタクリル酸メチル８５〜１００質量％およびアクリル酸エステル０〜１５質量％を含む単量体を重合して得た非架橋重合体（Ａ）７０〜９９質量部と、メタクリル酸メチル８５〜１００質量％およびアクリル酸エステル０〜１５質量％を含む単量体を架橋重合して得た平均粒子径５０〜３００μｍの架橋重合体（Ｂ）１〜３０質量部とからなる重合体混合物１００質量部に対して、飽和脂肪族アルコールからなる滑剤（Ｃ）０.０５〜５質量部を添加してなり、２３０℃、９８Ｎで測定したメルトインデックスが０.０５〜２.０ｇ／１０分であり、かつ窒素雰囲気中で２８０℃、２０分加熱したときの質量減少率が３〜４０％である樹脂成形機用洗浄剤である。
【００１１】
【発明の実施の形態】
以下、本発明の好適な実施形態について説明する。
【００１２】
本発明において、非架橋重合体（Ａ）は、メタクリル酸メチルを主成分とする重合体であり、具体的には、メタクリル酸メチル８５〜１００質量％およびアクリル酸エステル０〜１５質量％を含む単量体を重合して得たものである。
【００１３】
非架橋重合体（Ａ）に必要に応じて用いるアクリル酸エステルは、洗浄剤の溶融粘度を調整するために有用な成分である。このアクリル酸エステルの種類は特に限定されず、メタクリル酸メチルに１５質量％以下で共重合可能なものであればよい。具体例としては、アクリル酸メチル、アクリル酸エチル、アクリル酸プロピル、アクリル酸ブチル等が挙げられる。
【００１４】
アクリル酸エステルの使用量は、単量体において０〜１５質量％である。これが１５質量％を超えると、洗浄剤が加熱シリンダー内等で分解した場合、未溶融物が発生し易くなり、炭化物の発生原因となる。本発明においては、重合体（Ａ）中のアクリル酸エステルを１５質量％以下に抑えること等によって、加熱分解による質量減少率が低い洗浄剤を得る。
【００１５】
非架橋重合体（Ａ）は、従来より知られる懸濁重合法、塊状重合法、乳化重合法、溶液重合法等の各種の重合法により得ることができる。
【００１６】
本発明において、架橋重合体（Ｂ）も、メタクリル酸メチルを主成分とする重合体であり、具体的には、メタクリル酸メチル８５〜１００質量％およびアクリル酸エステル０〜１５質量％を含む単量体を架橋重合して得たものである。
【００１７】
架橋重合体（Ｂ）の平均粒子径は５０〜３００μｍの範囲内であり、特に１００〜２００μｍの範囲内が好ましい。この平均粒子径は、ミクロ型電磁振動ふるい器Ｍ−２型（筒井理化学器機(株)製）を使用し、サンプル質量１０ｇ、ふるいの振動時間１５分、メッシュ３０μｍ〜３５０μｍの各種に架橋重合体を分別し、（各種粒径×サンプル質量）の合計／サンプル質量の合計（１０ｇ）で算出した値である。
【００１８】
架橋重合体（Ｂ）は、一般的には、メタクリル酸メチル８５〜１００質量％およびアクリル酸エステル０〜１５質量％を含む単量体に、さらに架橋剤を添加し、好ましくは懸濁重合により架橋重合して、粒子状の重合体として得られる。また、一旦、塊状の架橋共重合体を製造してから、これを粉砕して粒子状の重合体を得ることもできる。
【００１９】
架橋重合体（Ｂ）に必要に応じて用いるアクリル酸エステルとしては、非架橋重合体（Ａ）に用いるアクリル酸エステルと同様のものが挙げられる。
【００２０】
架橋重合体（Ｂ）に用いる架橋剤としては、ジビニル化合物、ジアリル化合物など、重合可能な多官能基を有する単量体を用いることが好ましい。なお、架橋剤として多官能単量体を用いる場合、この多官能単量体はメタクリル酸メチルおよび必要に応じてアクリル酸エステルを含む単量体とは別のものとして、別途その質量を規定する。多官能単量体等の架橋剤の使用量は、メタクリル酸メチルおよび必要に応じてアクリル酸エステルを含む単量体１００質量部に対して、０.５〜１５質量部が好ましい。
【００２１】
非架橋重合体（Ａ）と、架橋重合体（Ｂ）との組成比は、両者の合計１００質量部を基準として、非架橋重合体（Ａ）が７０〜９９質量部、架橋重合体（Ｂ）が１〜３０質量部である。特に、非架橋重合体（Ａ）が８０〜９５質量部、架橋重合体（Ｂ）が５〜２０質量部であることが好ましい。
【００２２】
本発明において、滑剤（Ｃ）は飽和脂肪族アルコールからなり、これを添加することにより洗浄効果が向上する。飽和脂肪族アルコールの炭素数は１６から１９の範囲内であることが好ましい。特に、ステアリルアルコール、セチルアルコ―ルは、加熱シリンダー内に滞留し難いので最適である。
【００２３】
滑剤（Ｃ）は、非架橋重合体（Ａ）と架橋重合体（Ｂ）とからなる重合体混合物１００質量部に対し、０.０５〜５質量部、好ましくは０.２〜３質量部添加する。
【００２４】
以上説明した非架橋重合体（Ａ）、架橋重合体（Ｂ）、滑剤（Ｃ）を混合し、例えば押出機にてペレット化して、本発明の洗浄剤を得ることができる。また、本発明の洗浄剤は、この成分（Ａ）〜成分（Ｃ）を主成分として含有する組成物であるが、さらに所望に応じて、従来より知られる各種の添加剤を添加できる。
例えば、加熱分解性をコントロールするために安定剤を添加することができ、また可塑化安定性のために可塑剤を添加することもできる。これら添加剤は、例えば成分（Ａ）〜成分（Ｃ）を調合ブレンドする際に添加し、押出機にてペレット化すればよい。
【００２５】
本発明の洗浄剤は、２３０℃、９８Ｎで測定したメルトインデックスが０.０５〜２.０ｇ／１０分の範囲内にある。このメルトインデックスは、ＡＳＴＭ Ｄ−１２３８に準じて測定した値である。このメルトインデックスが２.０ｇ／１０分を超えると、加熱シリンダー内での溶融粘度が低くなり、残留樹脂を除去する作用が低下する。また、０.０５ｇ／１０分未満では、洗浄剤を加熱シリンダー内で可塑化するときのスクリューモーター負荷が増大し、円滑な可塑化ができないばかりか、洗浄剤が加熱シリンダー内に残留し、引き続き成形する樹脂で除去することが困難となる。
【００２６】
本発明の洗浄剤は、窒素雰囲気中で２８０℃、２０分加熱したときの質量減少率が３〜４０％である。この質量減少率が３％未満では、溶融粘度の低下に時間がかかり効率的な作業ができないばかりか、成形品中に洗浄剤が混入する場合もある。また、４０％を超えると、洗浄剤が加熱シリンダー内で可塑化された時点で既に大幅に溶融粘度が低下し、残留樹脂の除去が不十分になる。
【００２７】
樹脂成形機用の洗浄剤は、加熱シリンダー内等に残留している樹脂を除去することができ、しかも次に成形する樹脂材料によりその洗浄剤を除去できることが必要とされる。そして本発明の洗浄剤は、高い溶融粘度の状態にある時に加熱シリンダー内等の残留樹脂を除去し、次に成形する成形材料で洗浄剤を除去する段階では、その熱分解性が有効に働き洗浄剤の溶融粘度が低下し、容易に樹脂材料で洗浄剤を除去することが可能となる。
【００２８】
【実施例】
以下、実施例により、本発明を更に詳細に説明する。
【００２９】
［実施例１］
１．メタクリル酸メチルを主成分とする非架橋重合体（Ａ）の製造：
メタクリル酸メチル９.９ｋｇおよびアクリル酸メチル０.１ｋｇに、アゾビスイソブチロニトリル６ｇおよびｎ−オクチルメルカプタン８ｇを添加して攪拌し、均一溶液とした。次に、この均一溶液を、水３０ｋｇにポリメタクリル酸ナトリウム３ｇを添加した溶液が入った５０Ｌジャケット付重合槽内に投入し、攪拌した。そしてジャケットに温水を通して加熱し、８０℃で３時間重合反応を行った。得られた重合体を水洗、乾燥し、メタクリル酸メチルを主成分とする非架橋重合体（Ａ）のビーズを得た。
【００３０】
２．メタクリル酸メチルを主成分とする架橋重合体（Ｂ）の製造：
メタクリル酸メチル１０ｋｇおよび架橋剤としてのジメタクリル酸エチレングリコール１ｋｇに、アゾビスイソブチロニトリル６ｇを添加して攪拌し、均一溶液としたものを用いたこと以外は、上記非架橋重合体（Ａ）の製造工程と同様にして、平均粒子径１００μｍの架橋重合体（Ｂ）のビーズを得た。
【００３１】
３．洗浄剤の製造：
上記のようにして製造した非架橋重合体（Ａ）のビーズ８０質量部と、架橋重合体（Ｂ）のビーズ２０質量部をブレンドし、さらに滑剤（Ｃ）としてのステアリルアルコールを１質量部加えてブレンドし、４０φベント押出機でペレット化して、本発明の洗浄剤を得た。この洗浄剤のメルトインデックス（２３０℃、９８Ｎ）は０.６ｇ／１０分であり、質量減少率（２８０℃、２０分）は１２％であった。
【００３２】
４．洗浄剤の評価：
まず、第１の射出成形工程として、射出成形機（東芝製、ＩＳ８０ＦＰＡ３）を用いて、ＰＣ−ＰＢＴ樹脂（ポリカーボネート−ポリブチレンテレフタレート樹脂、米国ＧＥ社製、商品名ゼノイ１７３１黒）の射出成形を所望時間実施した。
【００３３】
次に、洗浄工程として、シリンダー温度２６０℃、スクリュー回転数７０ｒｐｍに設定し、洗浄剤を１ｋｇ投入して洗浄を実施したところ、短時間で充分に残留ＰＣ−ＰＢＴ樹脂を洗浄除去することができた。その後、メタクリル樹脂（三菱レイヨン(株)製、商品名アクリペットＶＨ クリア）を２ｋｇ投入して洗浄を実施したところ、加熱シリンダー内に残留する洗浄剤を短時間で充分除去することができた。
【００３４】
洗浄剤を充分除去した後、第２の射出成形工程として、１００ｍｍ×１００ｍｍ×３ｍｍ厚のメタクリル樹脂平板を成形した。平板の透明性および外観に特に問題は無く、メタクリル樹脂特有の高い透明性および外観が得られた。
【００３５】
［実施例２、３］
成分（Ａ）〜成分（Ｃ）の組成比を表１に示すように変更したこと以外は、実施例１と同様にして本発明の洗浄剤を製造し、評価した。洗浄剤の使用量は、実施例２では１.５ｋｇ、実施例３では１ｋｇであり、実施例１と同様に、短時間で充分に残留ＰＣ−ＰＢＴ樹脂を洗浄除去することができた。また、洗浄剤を除去する為に用いるメタクリル樹脂の量は、実施例２では２ｋｇ、実施例３では３ｋｇであり、実施例１と同様、このような少量のメタクリル樹脂により、残留洗浄剤を短時間で充分除去することができた。その結果を表１に示す。
【００３６】
【表１】
［比較例１］
洗浄工程において洗浄剤を使用せず、メタクリル樹脂５ｋｇで残留ＰＣ−ＰＢＴ樹脂を除去しようとしたこと以外は、実施例１と同様にしてメタクリル樹脂平板を作製した。しかし、残留ＰＣ−ＰＢＴ樹脂は十分に除去できず、第２の射出成形工程で得たメタクリル樹脂平板は、ＰＣ−ＰＢＴ樹脂の混入により濁っていた。
【００３８】
そこで洗浄工程におけるメタクリル樹脂の使用量を８ｋｇ〜１０ｋｇに増量して、再度、第１の射出成形工程、洗浄工程、第２の射出成形工程を実施したところ、ようやく本来の透明性を有するメタクリル樹脂平板を得ることができた。
【００３９】
［比較例２］
洗浄工程において、本発明の洗浄剤の代わりに、超高分子量メタクリル樹脂（三菱レイヨン(株)製、商品名アクリライトＬ）の粉砕品を１ｋｇ用いて残留ＰＣ−ＰＢＴ樹脂を除去し、その後、メタクリル樹脂を３ｋｇ投入し、超高分子量メタクリル樹脂を除去しようとしたこと以外は、実施例１と同様にしてメタクリル樹脂平板を作製した。しかし、ＰＣ−ＰＢＴ樹脂は充分除去できたものの、残留超高分子量メタクリル樹脂の除去が不充分であり、第２の射出成形工程で得たメタクリル樹脂平板には超高分子量メタクリル樹脂の残留が確認され、シルバー状の外観不良が発生していた。
【００４０】
【発明の効果】
以上説明したように、本発明の洗浄剤を使用すれば、樹脂成形機の加熱シリンダー内等に残留している樹脂を短時間で効率よく除去することができ、しかも次に成形する樹脂材料で洗浄剤を容易に除去することができる。したがって、本発明の洗浄剤を使用すれば、樹脂成形機の材料変更や色替え作業等を効率よく実施できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cleaning agent such as a heating cylinder and a screw of a resin molding machine, which is used for efficiently performing a material change and a color change operation of a resin molding machine such as an injection molding machine or an extrusion molding machine.
[0002]
[Prior art]
Resin molding machines such as injection molding machines and extrusion molding machines are excellent in that they can produce large quantities of a single product, and have so far contributed greatly to the development of the resin material field. Recently, however, the demands of users have diversified, and it has become essential to produce a small variety of resin molded products. As a result, the frequency of material change and color change of resin molding machines is increasing. For example, the most problematic problem in changing materials is cleaning of the resin material fused to the heating cylinder and screw of the resin molding machine.
[0003]
In other words, the method of disassembling and mechanically cleaning the heating cylinder and screw takes too much time and manpower and is not employed in normal operations. In general, an operation of washing and removing residual resin in the heating cylinder with a resin to be subsequently molded is performed. However, in such a cleaning operation, resin replacement is incomplete, and the amount of resin used for cleaning increases, which is uneconomical.
[0004]
Therefore, conventionally, a study has been made on a cleaning agent for efficiently changing the resin of the resin molding machine. For example, JP-A-3-230922 discloses a cleaning agent comprising a methacrylic polymer having a melt index of 0.05 to 20 g / 10 min measured at 230 ° C. and 10 kg. For example, JP-A-8-155969 discloses a cleaning agent for a molding machine in which 2 to 50 parts by mass of a thermoplastic superpolymer are mixed with 100 parts by mass of a thermoplastic resin.
[0005]
Moreover, various types of cleaning agents for resin molding machines are actually marketed, and they are roughly classified into a high viscosity type and a low viscosity type.
[0006]
[Problems to be solved by the invention]
However, the cleaning agent described in the above publication still has insufficient cleaning power. Of the commercial products, the high-viscosity type cleaning agent is effective in removing the resin staying in the heating cylinder, but it is difficult to remove this cleaning agent with the resin to be continuously molded. There is a drawback that defects such as butts and silver occur in the molded product. On the other hand, it is difficult for the low-viscosity type cleaning agent to completely remove the residual resin in the heating cylinder, and it is mixed in the molded product that is molded next. Furthermore, since this type of detergent contains a large amount of surfactants, foaming agents, plasticizers, etc., even if a small amount of detergent is mixed in the molded product, the mechanical properties and thermal properties deteriorate. Bring.
[0007]
In addition, commercially available products include inorganic filler-added types, which, like the high-viscosity types, are effective in removing the resin staying in the heating cylinder, but are continuously molded. Therefore, it is difficult to remove the inorganic filler, and there is a drawback that a silver-like appearance defect occurs when mixed with a molded product.
[0008]
An object of the present invention is to solve the above-described problems of the conventional techniques. Specifically, the resin remaining in the heating cylinder of the resin molding machine can be efficiently removed in a short time. And it aims at providing the washing | cleaning agent for resin molding machines which can remove the washing | cleaning agent easily with the resin material shape | molded next.
[0009]
[Means for Solving the Problems]
As a result of carrying out various studies to achieve the above object, the present inventors have found that a detergent containing a specific polymer mainly composed of methyl methacrylate at a specific composition ratio is very effective. The headline and the present invention were completed.
[0010]
That is, the present invention relates to 70 to 99 parts by mass of a non-crosslinked polymer (A) obtained by polymerizing a monomer containing 85 to 100% by mass of methyl methacrylate and 0 to 15% by mass of an acrylic ester, and methyl methacrylate. A polymer mixture comprising 1 to 30 parts by mass of a crosslinked polymer (B) having an average particle size of 50 to 300 μm obtained by crosslinking polymerization of a monomer containing 85 to 100% by mass and acrylic acid ester 0 to 15% by mass. Addition of 0.05 to 5 parts by mass of a lubricant (C) comprising a saturated aliphatic alcohol to 100 parts by mass, and a melt index measured at 230 ° C. and 98 N is 0.05 to 2.0 g / 10 min. And a cleaning agent for a resin molding machine having a mass reduction rate of 3 to 40% when heated at 280 ° C. for 20 minutes in a nitrogen atmosphere.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
[0012]
In the present invention, the non-crosslinked polymer (A) is a polymer mainly composed of methyl methacrylate, and specifically includes 85 to 100% by mass of methyl methacrylate and 0 to 15% by mass of acrylic ester. It is obtained by polymerizing monomers.
[0013]
The acrylic ester used as necessary for the non-crosslinked polymer (A) is a useful component for adjusting the melt viscosity of the cleaning agent. The kind of the acrylate ester is not particularly limited as long as it can be copolymerized with methyl methacrylate at 15% by mass or less. Specific examples include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and the like.
[0014]
The usage-amount of an acrylic ester is 0-15 mass% in a monomer. When this exceeds 15 mass%, when the cleaning agent is decomposed in a heating cylinder or the like, an unmelted material is easily generated, which causes generation of carbides. In the present invention, a detergent having a low mass reduction rate due to thermal decomposition is obtained by suppressing the acrylic acid ester in the polymer (A) to 15% by mass or less.
[0015]
The non-crosslinked polymer (A) can be obtained by various polymerization methods such as a conventionally known suspension polymerization method, bulk polymerization method, emulsion polymerization method, solution polymerization method and the like.
[0016]
In the present invention, the crosslinked polymer (B) is also a polymer containing methyl methacrylate as a main component, and specifically includes a monomer containing 85 to 100% by mass of methyl methacrylate and 0 to 15% by mass of an acrylate ester. It is obtained by crosslinking polymerization of a monomer.
[0017]
The average particle diameter of the crosslinked polymer (B) is in the range of 50 to 300 μm, and particularly preferably in the range of 100 to 200 μm. This average particle size is obtained by using a micro type electromagnetic vibration sieve M-2 type (manufactured by Tsutsui Rikenki Co., Ltd.), with a sample mass of 10 g, a vibration time of the sieve of 15 minutes, and various types of cross-linked polymers having a mesh size of 30 μm to 350 μm. Is a value calculated by the sum of (various particle size × sample mass) / total sample mass (10 g).
[0018]
The crosslinked polymer (B) is generally prepared by adding a crosslinking agent to a monomer containing 85 to 100% by mass of methyl methacrylate and 0 to 15% by mass of an acrylic ester, preferably by suspension polymerization. Crosslinking polymerization is performed to obtain a particulate polymer. It is also possible to produce a lump-shaped crosslinked copolymer and then pulverize it to obtain a particulate polymer.
[0019]
As an acrylic ester used as needed for a crosslinked polymer (B), the thing similar to the acrylic ester used for a non-crosslinked polymer (A) is mentioned.
[0020]
As the crosslinking agent used for the crosslinked polymer (B), it is preferable to use a monomer having a polymerizable polyfunctional group such as a divinyl compound or a diallyl compound. In addition, when using a polyfunctional monomer as a crosslinking agent, this polyfunctional monomer is different from a monomer containing methyl methacrylate and, if necessary, an acrylate ester, and its mass is separately defined. . The amount of the crosslinking agent such as a polyfunctional monomer is preferably 0.5 to 15 parts by mass with respect to 100 parts by mass of the monomer containing methyl methacrylate and, if necessary, an acrylate ester.
[0021]
The composition ratio of the non-crosslinked polymer (A) to the crosslinked polymer (B) is 70 to 99 parts by mass of the non-crosslinked polymer (A) and the crosslinked polymer (B ) Is 1 to 30 parts by mass. In particular, the non-crosslinked polymer (A) is preferably 80 to 95 parts by mass, and the crosslinked polymer (B) is preferably 5 to 20 parts by mass.
[0022]
In the present invention, the lubricant (C) comprises a saturated aliphatic alcohol, and the cleaning effect is improved by adding this. The saturated fatty alcohol preferably has 16 to 19 carbon atoms. In particular, stearyl alcohol and cetyl alcohol are optimal because they hardly stay in the heating cylinder.
[0023]
The lubricant (C) is added in an amount of 0.05 to 5 parts by mass, preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the polymer mixture composed of the non-crosslinked polymer (A) and the crosslinked polymer (B). To do.
[0024]
The cleaning agent of the present invention can be obtained by mixing the non-crosslinked polymer (A), the crosslinked polymer (B), and the lubricant (C) described above and pelletizing them with, for example, an extruder. Moreover, the cleaning agent of the present invention is a composition containing these components (A) to (C) as main components, and various other conventionally known additives can be added as desired.
For example, a stabilizer can be added to control heat decomposability, and a plasticizer can be added for plasticizing stability. These additives may be added, for example, when the components (A) to (C) are prepared and blended, and pelletized with an extruder.
[0025]
The cleaning agent of the present invention has a melt index measured at 230 ° C. and 98 N in the range of 0.05 to 2.0 g / 10 min. This melt index is a value measured according to ASTM D-1238. When this melt index exceeds 2.0 g / 10 minutes, the melt viscosity in the heating cylinder is lowered, and the action of removing the residual resin is lowered. Moreover, if it is less than 0.05 g / 10min, the screw motor load when plasticizing the cleaning agent in the heating cylinder increases, and not only smooth plasticization is possible, but also the cleaning agent remains in the heating cylinder and continues. It becomes difficult to remove with a resin to be molded.
[0026]
The cleaning agent of the present invention has a mass reduction rate of 3 to 40% when heated at 280 ° C. for 20 minutes in a nitrogen atmosphere. If the mass reduction rate is less than 3%, it takes a long time to lower the melt viscosity, and an efficient operation cannot be performed. In addition, a cleaning agent may be mixed in the molded product. On the other hand, if it exceeds 40%, the melt viscosity is already greatly reduced when the cleaning agent is plasticized in the heating cylinder, and the removal of the residual resin becomes insufficient.
[0027]
The cleaning agent for the resin molding machine is required to be able to remove the resin remaining in the heating cylinder and the like and to be able to remove the cleaning agent by the resin material to be molded next. The cleaning agent of the present invention effectively removes residual resin in the heating cylinder when it is in a high melt viscosity state, and its thermal decomposability works effectively at the stage of removing the cleaning agent with the molding material to be molded next. The melt viscosity of the cleaning agent decreases, and the cleaning agent can be easily removed with a resin material.
[0028]
【Example】
Hereinafter, the present invention will be described in more detail by way of examples.
[0029]
[Example 1]
1. Production of non-crosslinked polymer (A) mainly composed of methyl methacrylate:
6 g of azobisisobutyronitrile and 8 g of n-octyl mercaptan were added to 9.9 kg of methyl methacrylate and 0.1 kg of methyl acrylate and stirred to obtain a homogeneous solution. Next, this homogeneous solution was put into a 50 L jacketed polymerization tank containing a solution obtained by adding 3 g of sodium polymethacrylate to 30 kg of water and stirred. Then, warm water was passed through the jacket, and a polymerization reaction was carried out at 80 ° C. for 3 hours. The obtained polymer was washed with water and dried to obtain beads of a non-crosslinked polymer (A) mainly composed of methyl methacrylate.
[0030]
2. Production of cross-linked polymer (B) mainly composed of methyl methacrylate:
The non-crosslinked polymer (A) was used except that 10 kg of methyl methacrylate and 1 kg of ethylene glycol dimethacrylate as a crosslinking agent were added with 6 g of azobisisobutyronitrile and stirred to obtain a homogeneous solution. ), The crosslinked polymer (B) beads having an average particle diameter of 100 μm were obtained.
[0031]
3. Production of cleaning agents:
80 parts by mass of the non-crosslinked polymer (A) produced as described above and 20 parts by mass of the crosslinked polymer (B) are blended, and 1 part by mass of stearyl alcohol as a lubricant (C) is added. Were blended and pelletized with a 40φ vent extruder to obtain the cleaning agent of the present invention. The detergent had a melt index (230 ° C., 98 N) of 0.6 g / 10 minutes and a mass reduction rate (280 ° C., 20 minutes) of 12%.
[0032]
4). Evaluation of cleaning agent:
First, as a first injection molding process, an injection molding machine (manufactured by Toshiba, IS80FPA3) is used to perform injection molding of a PC-PBT resin (polycarbonate-polybutylene terephthalate resin, manufactured by US GE, trade name Zenoi 1731 black). Performed for the desired time.
[0033]
Next, as a cleaning process, the cylinder temperature was set to 260 ° C. and the screw rotation speed was set to 70 rpm, and 1 kg of cleaning agent was added to perform cleaning. As a result, the residual PC-PBT resin could be sufficiently cleaned and removed in a short time. It was. Thereafter, 2 kg of methacrylic resin (product name: Acrypet VH Clear, manufactured by Mitsubishi Rayon Co., Ltd.) was added to perform cleaning, and the cleaning agent remaining in the heating cylinder could be sufficiently removed in a short time.
[0034]
After sufficiently removing the cleaning agent, a 100 mm × 100 mm × 3 mm thick methacrylic resin flat plate was molded as a second injection molding step. There was no particular problem with the transparency and appearance of the flat plate, and high transparency and appearance peculiar to methacrylic resins were obtained.
[0035]
[Examples 2 and 3]
The cleaning agent of the present invention was produced and evaluated in the same manner as in Example 1 except that the composition ratio of component (A) to component (C) was changed as shown in Table 1. The amount of the cleaning agent used was 1.5 kg in Example 2 and 1 kg in Example 3. As in Example 1, the residual PC-PBT resin could be sufficiently washed and removed in a short time. Further, the amount of methacrylic resin used for removing the cleaning agent is 2 kg in Example 2 and 3 kg in Example 3. As in Example 1, such a small amount of methacrylic resin shortens the residual cleaning agent. It was able to be removed sufficiently in time. The results are shown in Table 1.
[0036]
[Table 1]
[Comparative Example 1]
A methacrylic resin flat plate was produced in the same manner as in Example 1 except that no cleaning agent was used in the washing step and an attempt was made to remove the residual PC-PBT resin with 5 kg of methacrylic resin. However, the residual PC-PBT resin could not be removed sufficiently, and the methacrylic resin flat plate obtained in the second injection molding process was cloudy due to the mixing of the PC-PBT resin.
[0038]
Therefore, the amount of methacrylic resin used in the cleaning process was increased to 8 kg to 10 kg, and the first injection molding process, the cleaning process, and the second injection molding process were performed again. A flat plate could be obtained.
[0039]
[Comparative Example 2]
In the washing step, the residual PC-PBT resin was removed using 1 kg of a pulverized product of ultra high molecular weight methacrylic resin (trade name Acrylite L, manufactured by Mitsubishi Rayon Co., Ltd.) instead of the cleaning agent of the present invention. A methacrylic resin flat plate was produced in the same manner as in Example 1 except that 3 kg of methacrylic resin was added and an attempt was made to remove the ultrahigh molecular weight methacrylic resin. However, although the PC-PBT resin was able to be removed sufficiently, the removal of the residual ultrahigh molecular weight methacrylic resin was insufficient, and it was confirmed that the ultrahigh molecular weight methacrylic resin remained on the methacrylic resin flat plate obtained in the second injection molding process. As a result, a silver-like appearance defect occurred.
[0040]
【The invention's effect】
As described above, if the cleaning agent of the present invention is used, the resin remaining in the heating cylinder of the resin molding machine can be efficiently removed in a short time, and the resin material to be molded next is used. The cleaning agent can be easily removed. Therefore, if the cleaning agent of the present invention is used, a material change or a color change operation of the resin molding machine can be efficiently performed.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000252327A JP4658295B2 (en) | 2000-08-23 | 2000-08-23 | Cleaning agent for resin molding machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000252327A JP4658295B2 (en) | 2000-08-23 | 2000-08-23 | Cleaning agent for resin molding machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002060792A JP2002060792A (en) | 2002-02-26 |
| JP4658295B2 true JP4658295B2 (en) | 2011-03-23 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000252327A Expired - Fee Related JP4658295B2 (en) | 2000-08-23 | 2000-08-23 | Cleaning agent for resin molding machine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4658295B2 (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5429351A (en) * | 1977-08-09 | 1979-03-05 | Asahi Chem Ind Co Ltd | Purging compound |
| JPH0374499A (en) * | 1989-08-17 | 1991-03-29 | Tokyo Ink Kk | Detergent for molding machine |
| JPH03230922A (en) * | 1990-02-05 | 1991-10-14 | Mitsubishi Rayon Co Ltd | Cleaning agent for resin molding machine |
| JPH08295763A (en) * | 1995-04-25 | 1996-11-12 | O K Fuasuto Kk | Cleaning resin composition |
-
2000
- 2000-08-23 JP JP2000252327A patent/JP4658295B2/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5429351A (en) * | 1977-08-09 | 1979-03-05 | Asahi Chem Ind Co Ltd | Purging compound |
| JPH0374499A (en) * | 1989-08-17 | 1991-03-29 | Tokyo Ink Kk | Detergent for molding machine |
| JPH03230922A (en) * | 1990-02-05 | 1991-10-14 | Mitsubishi Rayon Co Ltd | Cleaning agent for resin molding machine |
| JPH08295763A (en) * | 1995-04-25 | 1996-11-12 | O K Fuasuto Kk | Cleaning resin composition |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002060792A (en) | 2002-02-26 |
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