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EP-4219440-B1 - BATCH PREPARATION METHOD FOR ESTER-BASED MATERIAL

EP4219440B1EP 4219440 B1EP4219440 B1EP 4219440B1EP-4219440-B1

Inventors

  • KIM, HYUN KYU
  • MOON, JEONG JU
  • KIM, EUN SUK
  • HEO, Yun Gon

Dates

Publication Date
20260506
Application Date
20210917

Claims (10)

  1. A method for preparing an ester-based material, the method comprising: a step in which in a batch reactor, under a catalyst, at least one polycarboxylic acid selected from the group consisting of a terephthalic acid, a phthalic acid, an isophthalic acid, a cyclohexane dicarboxylic acid, a cyclohexane tricarboxylic acid, a trimellitic acid, and citric acid reacts with at least one mono-alcohol having 3 to 12 alkyl carbon atoms, wherein pressure in the reactor is configured such that the pressure at the early stage is 0.3 barg to 1.0 barg and the pressure at the latter stage is 0 barg to 0.5 barg, the pressure at the early stage being greater than the pressure at the latter stage, and the early and latter stages are divided based on any one of the time points when reaction conversion rate is 30% to 90%.
  2. The method of claim 1, wherein the batch reactor has an early stage pressure of 0.4 barg to 1.0 barg, and a latter stage pressure of 0 barg to 0.4 barg.
  3. The method of claim 1, wherein the mono-alcohol is added in excess of 20 mol% to 100 mol% relative to polycarboxylic acid equivalent.
  4. The method of claim 1, wherein: the reaction is performed in the presence of a catalyst; and the catalyst is added at one or more time points before the initiation of the reaction and in the course of the reaction.
  5. The method of claim 4, wherein the catalyst is added before the initiation of the reaction and in the course of the reaction.
  6. The method of claim 1, wherein the latter stage pressure gradually decreases as reactions proceed.
  7. The method of claim 1, further comprising adding an additional amount of the mono-alcohol in the course of reactions.
  8. The method of claim 1, wherein the preparation method is performed in a reaction unit comprising: a reactor in which an esterification reaction of a polycarboxylic acid with a mono-alcohol is performed; a column in which the mono-alcohol and water vaporized upon the esterification reaction are introduced from the reactor to perform gas-liquid separation, and liquid is fed into the reactor at a lower portion and gas is discharged from the top; a condenser liquefying the gas discharged from the top of the column, which is then converted into a liquid mixture; and a layer separator in which the liquid mixture is layer-separated into an organic layer and an aqueous layer, and the separated organic layer is fed to an upper end of the column.
  9. The method of claim 8, wherein: the reaction unit further comprises a pre-mixer placed upstream of the reactor; and the polycarboxylic acid and the mono-alcohol are fed into to the pre-mixer, mixed and preheated, and then transferred to the reactor.
  10. The method of claim 9, wherein the catalyst is added through at least one selected from among the reactor, the pre-mixer, and the liquid from the column.

Description

TECHNICAL FIELD The present invention relates to a batch preparation method of an ester-based material, the method configured to control the pressure of a reactor in the batch-wise preparation of the ester-based material. BACKGROUND ART Phthalate-based plasticizers had accounted for 92% of the global plasticizer market by the 20th century (see Mustafizur Rahman and Christopher S. Brazel, "The plasticizer market: an assessment of traditional plasticizers and research trends to meet new challenges", Progress in Polymer Science 2004, 29, 1223-1248), and are additives used for imparting flexibility, durability, and cold resistance mainly to polyvinyl chloride (hereinafter referred to as PVC) and lowering the viscosity during melting to improve processability. These phthalate-based plasticizers are added in various amounts to PVC and widely used in various applications from rigid products such as rigid pipes to soft products which may be used for such as food packaging materials, blood bags, flooring materials, etc. due to their soft and good flexibility, and thus are more closely related to real life than any other material, and the direct contact with the human body may not avoidable. However, despite the compatibility of the phthalate-based plasticizers with PVC and their excellent capability to impart flexibility, it has been argued recently about harmfulness of the PVC product containing the phthalate-based plasticizers that the phthalate-based plasticizers may leak out of the PVC product when used in real life, and act as a presumed endocrine disrupting (environmental hormone) substance and a carcinogen of the level of heavy metals (see N. R. Janjua et al., "Systemic Uptake of Diethyl Phthalate, Dibutyl Phthalate, and Butyl Paraben Following Whole-body Topical Application and Reproductive and Thyroid Hormone Levels in Humans", Environmental Science and Technology 2008, 42, 7522-7527). Especially, since the report about the leakage of di-(2-ethyl hexyl) phthalate (DEHP), which was the most used phthalate-based plasticizer in the US in the 1960s, out of the PVC product, the interest in environmental hormones has been added in the 1990s and global environmental regulations as well as extensive studies on hazards of the phthalate-based plasticizers to human have started. Therefore, in order to cope with environmental hormone issues and environmental regulations due to the leakage of the phthalate-based plasticizers, particularly di(2-ethylhexyl) phthalate, a number of researchers have been conducting research to develop a new, alternative, non-phthalate-based plasticizer which is free of phthalic acid used in the production of di(2-ethylhexyl) phthalate, a phthalate-based plasticizer which is phthalate-based but free of the leakage of plasticizers to be used for industrial purposes instead of di(2-ethylhexyl) phthalate, or a leakage inhibition technology which may inhibit the leakage of the phthalate-based plasticizers to greatly reduce the hazards to human and be in accordance with environmental standards. Accordingly, as ester-based plasticizers, materials which are free of environmental issues and thus may replace di(2-ethylhexyl) phthalate causing typical environmental issues have been under active development, and researches on the development of an ester-based plasticizer having excellent physical properties, as well as researches on facilities for preparing such the ester-based plasticizer have been actively conducted. In terms of process design, more efficient, economical, and simple process design has been required. Meanwhile, batch processing is most widely applied in industrial sites as a process of preparing the above ester-based plasticizer, and as a batch process, inventions such as a gas-liquid separation system for reflux of unreacted substances in a reactor and efficient removal of side reactants (Korean Patent Application Laid-Open No. 10-2019-0027622) and a system integrating facilities of a primary direct esterification reaction and a secondary trans esterification reaction for simpler batch process facilities (Korean Patent Application Laid-Open No. 10-2019-0027623) have been introduced. However, the batch processes introduced in such inventions are designed to enhance reactions through simplified or modified facilities, and thus are too costly to be applicable in industry due to addition of facilities or change of lines over processes. Thus, there remains a need for developing a process ensuring that reactions are optimized through alteration and control of process conditions. Related Art Document (Patent Document 1) Korean Patent Laid-Open Publication No. 10-2019-0027622(Patent Document 2) Korean Patent Laid-Open Publication No. 10-2019-0027623(Non-patent Document 1) Mustafizur Rahman and Christopher S. Brazel "The plasticizer market: an assessment of traditional plasticizers and research trends to meet new challenges" Progress in Polymer Science 2004, 29, 1223-1248(Non-patent Document 2