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PETG Pellets: Dimethyl Terephthalate with Ethylene Glycol and CHDM

작성자

Charlie

19. 10월 2026

PETG Pellets: Dimethyl Terephthalate with Ethylene Glycol and CHDM

PETG is PET in which part of the ethylene glycol is replaced by CHDM, which keeps the plastic clear and amorphous. Eastman's patent US 7,026,027 describes PETG 6763 as terephthalate with about 69 mol % ethylene glycol and 31 mol % CHDM, but gives no recipe for it. This blueprint is our own combination: that composition, made by the same patent's pilot-plant process (Example 12, written for a CHDM/neopentyl glycol copolyester), with ethylene glycol in place of neopentyl glycol as in Kibler's 1959 Eastman patent. The charge weights are our arithmetic. The picture: our diagram.

고급

About 5 hours

안내

Charge the reactor

Our charge for 31 mol % CHDM: 10.669 kg dimethyl terephthalate (54.9 mol, as in the patent's example), 2.456 kg CHDM (31 % of those moles) and 4.058 kg ethylene glycol, so the glycols total 1.5 times the ester moles as in the example. Add 53.4 g of catalyst solution (15 g titanium isopropoxide in 250 ml n-butanol). The patent's reactor held 18 gallons and had spiral agitators and a distillation column.

이 단계의 재료:

디메틸 테레프탈레이트10.669 kg

1,4-사이클로헥세인다이메탄올2.456 kg

에틸렌글리콜4.058 kg

필요한 도구:

타이타늄 아이소프로폭사이드

n-뷰탄올

접시 저울

재킷형 중합 반응기

분별 증류기

화학물질 비산 보안경

Ester interchange at 200 °C

Stir (forward 50 minutes, then reverse 10), heat to 200 °C and hold 2 hours. Methanol distils off through the column.

필요한 도구:

재킷형 중합 반응기

분별 증류기

표시기 달린 열전대

260 °C, then 280 °C

Raise to 260 °C for 30 minutes and weigh the distillate, then raise to 280 °C and weigh it again. The surplus ethylene glycol is driven off; Kibler found the CHDM stays in the polymer.

필요한 도구:

재킷형 중합 반응기

표시기 달린 열전대

접시 저울

Polymerise under vacuum

Switch the agitator direction every 6 minutes and pull vacuum at 13 Torr a minute down to 0.5 Torr. Hold full vacuum for 45 minutes at 25 rpm.

필요한 도구:

재킷형 중합 반응기

진공 펌프

진공계

콜드 트랩

Extrude and chop into pellets

Let nitrogen in, extrude the polymer at once and chop it into pellets. Check the composition: in the patent's example the polymer kept slightly less CHDM than was charged (38.1 % for 40.7 %).

필요한 도구: