JPS6031919A - Drying method of thermoplastic resin - Google Patents

Drying method of thermoplastic resin

Info

Publication number
JPS6031919A
JPS6031919A JP58139114A JP13911483A JPS6031919A JP S6031919 A JPS6031919 A JP S6031919A JP 58139114 A JP58139114 A JP 58139114A JP 13911483 A JP13911483 A JP 13911483A JP S6031919 A JPS6031919 A JP S6031919A
Authority
JP
Japan
Prior art keywords
resin
particle
temperature
drying
moisture
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP58139114A
Other languages
Japanese (ja)
Inventor
Yoshinori Nakamura
喜則 中村
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nissei ASB Machine Co Ltd
Original Assignee
Nissei ASB Machine Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nissei ASB Machine Co Ltd filed Critical Nissei ASB Machine Co Ltd
Priority to JP58139114A priority Critical patent/JPS6031919A/en
Publication of JPS6031919A publication Critical patent/JPS6031919A/en
Pending legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29BPREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B13/00Conditioning or physical treatment of the material to be shaped
    • B29B13/06Conditioning or physical treatment of the material to be shaped by drying
    • B29B13/065Conditioning or physical treatment of the material to be shaped by drying of powder or pellets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2067/00Use of polyesters or derivatives thereof, as moulding material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2067/00Use of polyesters or derivatives thereof, as moulding material
    • B29K2067/003PET, i.e. poylethylene terephthalate

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Abstract

PURPOSE:To improve drying efficiency and to reduce the drying time of material resin by conducting heat treatment due to electromagnetic induction to thermoplastic resin such as polyethylene terephthalate etc. to remove the moisture in the resin. CONSTITUTION:A microwave dielectric heater 6 is provided with a power source 7, a magnetron oscillator 8, an isolator 9, a matching device 10, etc. and equipped on the top of the material tank 3. This microwave dielectric heater 6 dielectrically heats material resin 5 in the material tank by the microwave from the magnetron oscillator 8. The temperature of the material resin 5 rises by the dielectric heating and this rise of temperature is based on heating due to molecular motion in the material resin. Therefore, the rise of temperature as resin particle is equal inside and outside the particle but since heat is radiated actually from the surface of the particle, the rise of temperature is larger inside the particle and the moisture in the resin particle is removed from inside the particle.

Description

【発明の詳細な説明】 この発明は成形材料として用いられる熱可塑性樹脂の乾
燥方法に関するものである。
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for drying a thermoplastic resin used as a molding material.

従木熱可塑性樹脂、たとえばポリエチレンテレフタレー
ト樹脂(以後PE1T樹脂と称する)を用いて工業部品
、一般雑貨品及び各種瓶等を射出成形又はブロー成形を
行う場合、必ず成形前の材料樹脂を3時間から6時間に
渡り脱湿乾燥を行っていた。
When injection molding or blow molding industrial parts, general miscellaneous goods, various bottles, etc. using a thermoplastic resin such as polyethylene terephthalate resin (hereinafter referred to as PE1T resin), be sure to use the material resin for at least 3 hours before molding. Dehumidification and drying was performed for 6 hours.

これは、PET樹脂が加熱溶融される過程で、その中に
水分が存在すると、主鎖中のエステル結合が容易に加水
分解を発生させ、大巾な分子量低下(固有粘度値の低下
)、物性強度の低下の原因となる。更に高温に於いては
、切断点で生成したエチレングリコールのテレフタル酸
の半エステルからエチレングリコールが離脱、転位して
アセトアルデヒドとなって遊離し、一部は樹脂中に残留
する。
This is because when PET resin is heated and melted, if moisture is present in it, the ester bonds in the main chain easily undergo hydrolysis, leading to a drastic drop in molecular weight (lower intrinsic viscosity) and physical properties. This causes a decrease in strength. Furthermore, at high temperatures, ethylene glycol is separated from the terephthalic acid half ester of ethylene glycol produced at the cutting point, rearranged, and liberated as acetaldehyde, with a portion remaining in the resin.

PET樹脂による炭酸飲料瓶は充填する内容物によって
も異なるが、例えばコーラ類は瓶ヘッドスペース内に析
出するアセトアルデヒド量を3マイクログラム/リツタ
ーと定めるなど風味変化に厳しい管理が要求される。従
いアセトアルデヒドの発生を極力少くすることもPET
樹脂乾燥の大きな目的であり、一般にPET樹脂の溶融
時前に含まれる水分は0.003〜0.005%が好ま
しいとされている。
Carbonated beverage bottles made of PET resin vary depending on the contents to be filled, but for example, colas require strict control over flavor changes, such as setting the amount of acetaldehyde that precipitates in the bottle headspace at 3 micrograms/liter. Therefore, it is also important to minimize the generation of acetaldehyde when using PET.
This is a major purpose of resin drying, and it is generally said that the moisture content of PET resin before melting is preferably 0.003 to 0.005%.

しかしながらPET樹脂に含まれる水分量を前記値まで
下げることは容易ではない。現在用いられている方法の
ほとんどは、次の様な手段による。
However, it is not easy to reduce the amount of water contained in PET resin to the above value. Most of the methods currently used are as follows.

即ち乾燥ヒーターに於いてブロワ−より送られて来た空
気を160〜180°Cに加熱し、これを乾燥ホツバー
に送り込む。乾燥ホラ・七−内には含湿した材料が投入
されておりホッパー下部より乾燥熱風がホッパー全体に
広がる。
That is, the air sent from the blower is heated in the drying heater to 160 to 180°C, and then sent to the drying hotber. Moist material is put into the drying hopper, and dry hot air is spread throughout the hopper from the bottom of the hopper.

含湿しだPET樹脂の表面に接触した乾燥熱風は、PE
T樹脂の表面を徐々に加熱し、樹脂内部に含まれている
水分を除去し始める。この水分により乾燥空気は徐々に
含湿されホラ・ぐ−上部より除湿室にもどる。
The dry hot air that came into contact with the surface of the moistened PET resin
The surface of the T-resin is gradually heated and the water contained inside the resin begins to be removed. The dry air is gradually moistened by this moisture and returns to the dehumidifying chamber from the upper part of the hollow chamber.

除湿室には除湿剤モレキュラーシーブスが満杯に入って
おり含湿空気の水分はこのモレキュラーシーブスに付着
吸湿される。そして再度乾燥ヒーターにより加熱され乾
燥ホッパーに送られる。この間除湿室内のモレキュラー
シーブスはその能力を無限に使用出来る訳ではなく、あ
る段階になるとその能力は飽和状態になる。この時は上
記サイクルを停止し、モレキュラーシーブス自身を再生
する為、加熱空気に於いて加熱離水しなければならない
The dehumidification chamber is filled with dehumidifying molecular sieves, and the moisture in the humid air adheres to and is absorbed by the molecular sieves. Then, it is heated again by the drying heater and sent to the drying hopper. During this time, the molecular sieves in the dehumidifying room cannot use their capacity indefinitely, and at a certain stage, their capacity becomes saturated. At this time, the above cycle must be stopped, and in order to regenerate the molecular sieve itself, it must be heated and water-separated in heated air.

又、前記した含水率0゜003〜0.005%を得るに
は、連続4〜6時間の除湿乾燥が必要であり、故に乾燥
ホッノぐ−は非常に大きなものとなる。例えば1時間7
0 K9のPET樹脂を溶融するプロー成形機に於いて
は、一般に300〜350リツターの乾燥ホッパーが必
要となる。
In addition, in order to obtain the moisture content of 0.003 to 0.005% as described above, continuous dehumidification and drying for 4 to 6 hours is necessary, and therefore the drying material becomes very large. For example, 1 hour 7
A blow molding machine that melts 0 K9 PET resin generally requires a drying hopper of 300 to 350 liters.

更に前記した様に乾燥ヒーター、再生ヒーター、ブロワ
−などが必要となり、その電気容量は著しく大キい。又
乾燥ホッパーと、ヒーター、モレキュラーシーブス、ブ
ロワ−等をまとめたユニットとの間の空気配管なども犬
がかりなものとなり、その設置スペースも大きく、これ
らから現状の材料乾燥装置は使用側からみると決して満
足されるものではなかった。
Furthermore, as mentioned above, a drying heater, regeneration heater, blower, etc. are required, and their electric capacity is extremely large. In addition, the air piping between the drying hopper and the unit that includes the heater, molecular sieves, blower, etc. is also complicated and requires a large installation space. It was never satisfying.

本発明は上記事情から考えられたものであって、その目
的とするところは、外部熱量をPET樹脂などに当て外
部から内部への熱量の移行により樹脂を加熱し、膨張し
た水分を取り除くと云う効率の悪さと、電力消費が多く
、設置スペースなども広く要求される従来方法の欠点を
排除した新たな熱可塑性樹脂の乾燥方法を提供すること
にある。
The present invention was conceived in view of the above circumstances, and its purpose is to apply external heat to PET resin, heat the resin by transferring heat from the outside to the inside, and remove the expanded moisture. It is an object of the present invention to provide a new method for drying thermoplastic resins that eliminates the drawbacks of conventional methods such as low efficiency, high power consumption, and large installation space requirements.

上記目的によるこの発明はポリエチレンテレフタレート
などの熱可塑性樹脂中の水分を、電磁誘導を利用した誘
電加熱により除去することを特徴とするものである。
The present invention for the above purpose is characterized in that moisture in a thermoplastic resin such as polyethylene terephthalate is removed by dielectric heating using electromagnetic induction.

この発明における誘電加熱は誘電物質(プラスチック、
ガラスなどの非金属の固体、水、油など)の誘電損(分
子間結合力の抵抗)によるものであり、物質自身の分子
運動によって発熱するために、物質表面からの熱伝導に
よる従来の加熱法とは著しく異なるものである。
Dielectric heating in this invention refers to dielectric materials (plastic,
This is due to the dielectric loss (resistance of intermolecular bonding force) of nonmetallic solids such as glass, water, oil, etc., and heat is generated by the movement of the molecules of the material itself, so conventional heating by heat conduction from the surface of the material This is significantly different from the law.

以下この発明を図示の装置により詳細に説明する。The present invention will be explained in detail below using the illustrated apparatus.

図中1は材料混線スクリュ2を内部に有する射出装置、
3は射出装置1に取付けた材料タンクで、材料落下口4
より射出装置内に、粒状の材料樹脂5を供給する構造よ
りなる。
In the figure, 1 is an injection device having a material mixing screw 2 inside;
3 is a material tank attached to the injection device 1, and the material drop port 4
The structure is such that granular material resin 5 is supplied into the injection device.

6はマイクロ波誘電加熱装置で、上記材料タンク3の頂
部に取付けられている。このマイクロ波誘電加熱装置6
は、電源7、マグネトロン発振器8、アイソレータ9、
整合器10などを備え、材料タンク内の材料樹脂5を、
マグネトロン発振器8からのマイクロ波により誘電加熱
する。
A microwave dielectric heating device 6 is attached to the top of the material tank 3. This microwave dielectric heating device 6
is a power supply 7, a magnetron oscillator 8, an isolator 9,
Equipped with a matching device 10, etc., the material resin 5 in the material tank is
Dielectric heating is performed by microwaves from the magnetron oscillator 8.

との誘電加熱により材料樹脂5の温度が上昇するのであ
るが、これは材料樹脂における分子運動による発熱であ
るため、樹脂粒子としての温度上昇は内外ともに同一で
あるが、実際には表面からの放熱があるため、粒子内部
の方が温度上昇が大きく、樹脂粒子中の水分は内部から
除去されるようになる。
The temperature of the resin material 5 rises due to the dielectric heating between the material and the resin, but since this is heat generation due to molecular motion in the material resin, the temperature rise of the resin particles is the same both inside and outside, but in reality, the temperature rise from the surface increases. Due to heat dissipation, the temperature rises larger inside the particles, and the moisture in the resin particles is removed from the inside.

次に上記装置を使用した乾燥を行った結果を示す。Next, the results of drying using the above device will be shown.

マイクロ波誘電加熱装置 定格電圧100■、定格周波数5Q’Hz、定格高周波
出力500W、発振1周波数2450±5Q MH2加
熱時間 15分、加分 材料樹脂 炭酸飲料用PET樹脂 固有粘度 0.73 採取量約20f 実施例1 加熱時間 15分 実施例2 加熱時間 加分 なお、含水率0.4%は、放置状態にあるPET樹脂の
含水量が0.4係であることによる。
Microwave dielectric heating device Rated voltage 100■, Rated frequency 5Q'Hz, Rated high frequency output 500W, Oscillation 1 frequency 2450±5Q MH2 heating time 15 minutes, Additional material resin PET resin for carbonated drinks Intrinsic viscosity 0.73 Collection amount approx. 20f Example 1 Heating time 15 minutes Example 2 Heating time Additional Note that the moisture content of 0.4% is due to the fact that the moisture content of the PET resin in the standing state is 0.4%.

比較例 同一条件のPET樹脂を脱湿装置付熱風乾燥機を用いた
結果の含水率は下記のとおりであった。
Comparative Example The moisture content of PET resin under the same conditions using a hot air dryer with a dehumidifying device was as follows.

7− 加 熱 前 加分加熱後 60分加熱後含水率(%) 
0.401 0.294 0.0813上記結果から明
らかなように、本発明の方法は従来の熱風乾燥機による
場合よりも、乾燥効果が一段とすぐれ、材料樹脂の乾燥
時間を著しく短縮し得るばかりか、乾燥装置を簡略化す
ることができるなどの特長を有する。
7- Before heating After additional heating Moisture content after 60 minutes of heating (%)
0.401 0.294 0.0813 As is clear from the above results, the method of the present invention not only has a much better drying effect than the method using a conventional hot air dryer, but also can significantly shorten the drying time of the material resin. , the drying equipment can be simplified.

【図面の簡単な説明】[Brief explanation of the drawing]

図面はこの発明に係る熱加塑性樹脂の乾燥方法を実施し
得る装置を備えだ射出装置の一部縦断側面図を示すもの
である。
The drawing shows a partially longitudinal sectional side view of an injection device equipped with an apparatus capable of carrying out the method of drying thermoplastic resin according to the present invention.

Claims (1)

【特許請求の範囲】[Claims] ポリエチレンテレフタレートなどの熱可塑性樹脂中の水
分を、電磁誘導を利用した誘電加熱により除去すること
を特徴とする熱可塑性樹脂の乾燥方法。
A method for drying thermoplastic resins, which includes removing moisture in thermoplastic resins such as polyethylene terephthalate by dielectric heating using electromagnetic induction.
JP58139114A 1983-07-29 1983-07-29 Drying method of thermoplastic resin Pending JPS6031919A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP58139114A JPS6031919A (en) 1983-07-29 1983-07-29 Drying method of thermoplastic resin

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP58139114A JPS6031919A (en) 1983-07-29 1983-07-29 Drying method of thermoplastic resin

Publications (1)

Publication Number Publication Date
JPS6031919A true JPS6031919A (en) 1985-02-18

Family

ID=15237814

Family Applications (1)

Application Number Title Priority Date Filing Date
JP58139114A Pending JPS6031919A (en) 1983-07-29 1983-07-29 Drying method of thermoplastic resin

Country Status (1)

Country Link
JP (1) JPS6031919A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6356602U (en) * 1986-09-30 1988-04-15
JPH01118409A (en) * 1987-11-02 1989-05-10 Matsuji Nakagome Continuously drying and feeding device of resin material
JPH02227213A (en) * 1989-02-28 1990-09-10 Sanyo Electric Co Ltd Microwave drying equipment
CN102398321A (en) * 2011-11-16 2012-04-04 宁波高新区安立特电气科技有限公司 Rubber and plastic drying machine

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5646968A (en) * 1979-09-25 1981-04-28 Nippon Light Metal Co Load shifter mounting apparatus for panel wall

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5646968A (en) * 1979-09-25 1981-04-28 Nippon Light Metal Co Load shifter mounting apparatus for panel wall

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6356602U (en) * 1986-09-30 1988-04-15
JPH01118409A (en) * 1987-11-02 1989-05-10 Matsuji Nakagome Continuously drying and feeding device of resin material
JPH02227213A (en) * 1989-02-28 1990-09-10 Sanyo Electric Co Ltd Microwave drying equipment
CN102398321A (en) * 2011-11-16 2012-04-04 宁波高新区安立特电气科技有限公司 Rubber and plastic drying machine

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