U.S. patent application number 13/612307 was filed with the patent office on 2013-02-28 for polyvinylchloride composition with a di(c4-c20)alkyl cyclohexane-1,4-dicarboxylate having high cis content.
This patent application is currently assigned to HANWHA CHEMICAL CORPORATION. The applicant listed for this patent is Young-kyun Choi, Kyong-jun Yoon. Invention is credited to Young-kyun Choi, Kyong-jun Yoon.
Application Number | 20130053492 13/612307 |
Document ID | / |
Family ID | 42217917 |
Filed Date | 2013-02-28 |
United States Patent
Application |
20130053492 |
Kind Code |
A1 |
Yoon; Kyong-jun ; et
al. |
February 28, 2013 |
Polyvinylchloride Composition with a DI(C4-C20)Alkyl
Cyclohexane-1,4-Dicarboxylate Having High CIS Content
Abstract
Provided is a cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate
which exhibits superior plasticizing property for PVC resin.
Instead of a phthalate- or terephthalate-based aromatic ester
derivative, 60% or more cis-dimethyl cyclohexane-1,4-dicarboxylate
is used as a starting material. The 60% or more cis-dimethyl
cyclohexane-1,4-dicarboxylate is subjected to transesterification
with (C4-C20) primary alcohol to prepare 60% or more
cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate. Methanol
produced as a byproduct during the transesterification is removed
and some of the primary alcohol, which is evaporated, is recycled.
Thus prepared 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate exhibits superior plasticizer
characteristics, including good plasticizing efficiency for PVC
resin, high absorption rate, good product transparency after
gelling, less bleeding toward the surface upon long-term use, and
the like.
Inventors: |
Yoon; Kyong-jun; (Daejeon,
KR) ; Choi; Young-kyun; (Daejeon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Yoon; Kyong-jun
Choi; Young-kyun |
Daejeon
Daejeon |
|
KR
KR |
|
|
Assignee: |
HANWHA CHEMICAL CORPORATION
Seoul
KR
|
Family ID: |
42217917 |
Appl. No.: |
13/612307 |
Filed: |
September 12, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13124803 |
Jul 7, 2011 |
8299292 |
|
|
PCT/KR2009/005980 |
Oct 16, 2009 |
|
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|
13612307 |
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Current U.S.
Class: |
524/285 |
Current CPC
Class: |
C07C 69/75 20130101;
C08K 5/12 20130101; C08K 5/0016 20130101; C08K 5/12 20130101; C07C
2601/14 20170501; C07C 67/03 20130101; C07B 2200/09 20130101; C07C
69/75 20130101; C08L 27/06 20130101; C07C 67/03 20130101 |
Class at
Publication: |
524/285 |
International
Class: |
C08K 5/092 20060101
C08K005/092; C08L 27/06 20060101 C08L027/06 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 16, 2008 |
KR |
10-2008-0101629 |
Jul 10, 2009 |
KR |
10-2009-0063075 |
Claims
1. A polyvinyl chloride (PVC) composition comprising
di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate having a cis content
of 60-90%.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of co-pending
U.S. patent application Ser. No. 13/124,803, filed Oct. 16, 2009,
which claims priority to Korean Patent Application Nos.
10-2009-0063075 and KR 10-2008-0101629, filed Jul. 10, 2009 and
Oct. 16, 2008, respectively, each of which is incorporated herein
by reference in their entirety
TECHNICAL FIELD
[0002] The present invention relates to a method for preparing 60%
or more cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate, which
exhibits superior plasticizing property for polyvinyl chloride
(PVC) resin.
[0003] Further, the present invention relates to a method for
preparing 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate with high purity and high yield by
minimizing side reactions.
[0004] That is to say, the present invention relates to a method
for preparing higher alkyl cyclohexane-1,4-dicarboxylate with
higher purity without side reactions by transesterifying dimethyl
cyclohexane-1,4-dicarboxylate having a particular stereostructure
with (C4-C20) higher alcohol, rather than using an aromatic
compound such as phthalate and terephthalate derivatives as
starting material, thereby maintaining the stereostructure.
[0005] More specifically, the present invention relates to a method
for preparing 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate without side reactions and with high
purity through transesterification of 60% or more cis-dimethyl
cyclohexane-1,4-dicarboxylate as starting material with one or more
alcohol(s) selected from (C4-C20) primary alcohol.
BACKGROUND ART
[0006] Phthalates, e.g. dibutyl, dioctyl or diisononyl phthalate,
have been very frequently used as plasticizers for plastics such as
polyvinyl chloride (PVC). However, recently, health concerns about
their use have been raised, and their use in toys or other products
is increasingly criticized. In some countries, their use is
prohibited. It is known through long-term animal studies that
phthalates may induce peroxisome proliferation, which may be the
cause of liver cancer, in mice and rats. Accordingly, demand on
alternative plasticizers, which are safe for humans and the
environment, is on the increase.
[0007] As an alternative, di(C6-C12)alkyl cyclohexanoate-based
plasticizers are evaluated as an eco-friendly and safe material
without toxicity. They are obtained by first preparing phthalate
plasticizers or terephthalate plasticizers and then converting them
to cyclohexanes through addition of hydrogens to the benzene ring
of the plasticizer. However, according to the method, since the
cyclohexanoate-based plasticizer is prepared by direct
hydrogenation after preparing the high-molecular-weight
terephthalate plasticizer having (C6-C12)alkyl groups, the
hydrogenation of the benzene ring is relatively difficult due to
the steric hindrance by the long high-molecular-weight aromatic
chain and the high viscosity of the reaction solution. As a result,
a more vigorous reaction condition is required to solve the
difficulties of the hydrogenation, which increases the risk of side
reactions, including the breakage of the long carbon chain,
decomposition or reduction of ester groups, etc., thereby reducing
product purity. Further, since it is impossible to control an
isomer of the cis/trans content of the resultant cyclohexanoate, it
is difficult to selectively prepare the 60% or more cis-dimethyl
cyclohexane-1,4-dicarboxylate desired by the present invention.
[0008] Korean Patent No. 10-0635396 proposes a use of
cyclohexane-1,3- and -1,4-dicarboxylic acid derivatives as a
plastic plasticizer, and discloses a material prepared by
hydrogenation of isophthalate and terephthalate, and a preparation
method thereof. However, since the above-mentioned patent describes
on the hydrogenation, which is performed on terephthalate, the
afore-said problem remains.
DISCLOSURE
Technical Problem
[0009] After testing physical properties of 60% or more
cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate as a plasticizer
for PVC resin, the inventors of the present invention have found
out that it exhibits superior plasticizing property for PVC resin.
They have found out that di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate shows different plasticizing property
depending on the cis/trans contents. Especially, they have found
out that the plasticizing effect is very superior when the cis
content is 60% or more.
[0010] However, at present, cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate is not available in commercial scale.
Through consistent researches on the preparation of 60% or more
cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate, the inventors
have developed a commercially available method for stably preparing
60% or more cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate
without side reactions and with superior yield.
[0011] The inventors have developed a simple process of preparing
60% or more cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate
without side reactions and with high purity by reacting 60% or more
cis-dimethyl cyclohexane-1,4-dicarboxylate with a (C4-C20) primary
alcohol under normal pressure, without a process of hydrogenating
dialkyl terephthalate under high temperature and high pressure as
an existing technique.
[0012] Accordingly, an object of the present invention is to
provide a novel method for preparing 60% or more
cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate which exhibits
superior plasticizing property for PVC resin.
Technical Solution
[0013] The present invention provides a method for preparing 60% or
more cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate by
subjecting 60% or more cis-dimethyl cyclohexane-1,4-dicarboxylate
as a starting material to transesterification with one or more
alcohol(s) selected from (C4-C20) primary alcohol, rather than
using phthalate or terephthalate derivatives as starting materials,
in a reactor in the presence of a catalyst in order to prepare a
di(C4-C20)alkyl ester compound of a cyclohexane structure, as shown
in Scheme 1.
[0014] The methanol byproduct produced during the process may be
removed after being condensed at a condenser equipped at the upper
portion of the reactor. Another condenser may be equipped between
the reactor and the condenser to condense some of the (C4-C20)
primary alcohol, which is evaporated, and introduce it again into
the reactor. A purification tower may be used instead of the
condenser. A purification tower (which may or may not include an
additional heat source supply system) operated with a reflux ratio
of 0.1-20 may be equipped at the upper portion of the reactor, so
that methanol is separated and removed from the primary alcohol at
the upper portion and the purified primary alcohol is recovered and
introduced again into the reactor at the lower portion.
[0015] Unless the methanol byproduct is removed at the condenser at
the upper portion and the higher primary alcohol reactant is
condensed between the condenser and the reactor and introduced
again into the reactor, the desired di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate with high purity may not be obtained
because of decreased reaction purity, and the cost for purification
may increase.
##STR00001##
[0016] In scheme 1, R represents (C4-C20)alkyl.
[0017] The 60% or more cis-dimethyl cyclohexane-1,4-dicarboxylate
which is used as a starting material in the present invention is
advantageous in that no hydrogenation process is required because
the benzene ring is saturated with hydrogen. The 60% or more
cis-dimethyl cyclohexane-1,4-dicarboxylate may have a cis content
of 60-90%, more preferably, 70-90%.
[0018] The 60% or more cis-dimethyl cyclohexane-1,4-dicarboxylate
and the (C4-C20) primary alcohol are used in a molar ratio of 1:2
to 1:4. Outside the range, the primary alcohol may be evaporated
during transesterification and unreacted dimethyl
cyclohexane-1,4-dicarboxylate may remain. Or, a large amount of
unreacted primary alcohol may remain after the reaction is
completed, and it a lot of time may be required to remove them.
[0019] The (C4-C20) primary alcohol may be derived from a (C4-C20)
saturated hydrocarbon. Examples may include n-butyl alcohol,
isobutyl alcohol, isoheptyl alcohol, 2-ethylhexyl alcohol, isononyl
alcohol, isodecyl alcohol, 2-propylheptyl alcohol, and the like,
but not limited thereto.
[0020] The catalyst used in the present invention is added to
facilitate the transesterification. It may be used in an amount of
0.01 to 1.0 wt %, more preferably 0.05 to 0.5 wt %, based on the
60% or more cis-dimethyl cyclohexane-1,4-dicarboxylate. If the
catalyst is used in an amount less than 0.01 wt %, the reaction may
not proceed well. And, an amount exceeding 1.0 wt % is uneconomical
because the reaction rate and yield do not increase in proportion
to the addition amount of the catalyst.
[0021] The catalyst is one capable of facilitating
transesterification, and may be one or more selected from a group
consisting of organometals such as tetra(C3-C10)alkyl titanate and
polymers thereof, metal salts such as aluminum sulfate, lithium
fluoride, potassium chloride, cesium chloride, calcium chloride,
iron chloride, aluminum phosphate, potassium carbonate, etc., metal
oxides such as heteropoly acid, etc., natural/synthetic zeolites,
cation/anion exchange resins, and acid catalysts such as sulfuric
acid, hydrochloric acid, phosphoric acid, nitric acid,
p-toluenesulfonic acid, methanesulfonic acid, alkyl sulfate, etc.
Among them, one or more selected from a group consisting of
tetraisopropyl titanate, tetra-n-butyl titanate, tetraoctyl
titanate and a mixture thereof may be preferably used.
[0022] In the present invention, the transesterification is carried
out at 140 to 220.degree. C. for 2 to 6 hours. Once the reaction
begins, transesterification occurs between the 60% or more
cis-dimethyl cyclohexane-1,4-dicarboxylate and the primary alcohol.
During the process, methanol is produced as byproduct. The methanol
byproduct needs to be removed continuously from the reactor through
distillation for the reaction to proceed stably. When methanol is
evaporated above a certain temperature, the primary alcohol may be
evaporated together. Therefore, the primary alcohol needs to be
separated from methanol and recycled to the reactor. By
continuously separating the primary alcohol which is distilled
along with methanol and recycling it to the reactor, the content of
the primary alcohol consumed in the reaction and the reaction
purity may be maintained.
[0023] In the present invention, in order to remove the methanol
byproduct produced during the transesterification and to recycle
the partially evaporated primary alcohol to the reactor, methanol
is condensed and removed by a condenser equipped at the upper
portion of the reactor and the partially evaporated primary alcohol
is condensed and recycled to the reactor by another condenser
equipped between the reactor and the condenser. Further, as
described above, a purification tower may be used instead of the
condenser. A purification tower (which may or may not include an
additional heat source supply system) operated with a reflux ratio
of 0.1-20 may be equipped at the upper portion of the reactor, so
that methanol is separated and removed from the primary alcohol at
the upper portion and the purified primary alcohol is recovered and
introduced again into the reactor at the lower portion.
[0024] The reactor that may be used for the transesterification of
the present invention includes a batch reactor, a mixed flow
reactor, a tubular reactor, etc., but not limited thereto.
[0025] A process for preparing 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate in accordance with the present
invention is illustrated in FIG. 1. Referring to FIG. 1, reaction
byproduct methanol ({circle around (6)}) produced in a reactor
({circle around (1)}) where transesterification occurs and
partially evaporated primary alcohol are condensed and
phase-separated by a primary condenser ({circle around (2)})
maintained at an adequate temperature. Thus separated liquid
primary alcohol ({circle around (7)}) is recycled into the reactor
and subjected to transesterification, and gaseous methanol ({circle
around (8)}) is transferred to a secondary condenser ({circle
around (3)}), where it is condensed into liquid and removed to a
vessel ({circle around (11)}). In case a purification tower is used
instead of the condenser ({circle around (2)}) in order to attain
higher methanol separation efficiency, a purification tower (which
may or may not include an additional heat source supply system)
operated with a reflux ratio of 0.1-20 is equipped to separate
methanol from the primary alcohol. Methanol is separated at the
upper portion and transferred to the secondary condenser ({circle
around (3)}). After being condensed there, some of the methanol is
recycled to the purification tower and the remaining is separated.
At the lower portion of the purification tower, the purified
primary alcohol is recovered and introduced again into the
reactor.
[0026] Methanol boils at 64.6.degree. C., whereas the primary
alcohol used in the reaction has a much higher boiling point. For
example, 2-ethylhexyl alcohol boils at 183.degree. C. and isononyl
alcohol boils at 203.degree. C. However, within the reaction
temperature range of 140-220.degree. C., some of the primary
alcohol is evaporated together with methanol. The evaporation of
the primary alcohol results in a significant change of the
proportion of reactants in the reactor and it becomes difficult to
maintain a stable reaction. Thus, the evaporated primary alcohol
({circle around (7)}) needs to be separated and recycled to the
reactor. In order to effectively perform this, two condensers are
equipped at the upper portion of the reactor. That is, a primary
condenser is equipped at the upper portion of the reactor, and a
secondary condenser is equipped to condense the gas that has passed
through the primary condenser. The primary condenser condenses and
separates the primary alcohol and then recycles it to the reactor.
The secondary condenser condensed methanol into liquid and
separates it. The primary condenser which condensed the primary
alcohol is maintained at a temperature range of 70-180.degree. C.,
which is higher than the boiling point of methanol and lower than
the boiling point of the primary alcohol. A temperature range of
90-150.degree. C. may be more preferable. And, the secondary
condenser which needs to condense the entire amount of the gaseous
methanol that has passed through the primary condenser is
maintained in a temperature range of 60.degree. C. or below, which
is lower than the boiling point of methanol. A temperature range of
40.degree. C. or lower may be more preferable.
[0027] When the transesterification continues for 2-6 hours, the
reaction is completed and no more methanol is produced. When the
reaction is completed, unreacted primary alcohol and catalyst
remain in the reaction solution in addition to the desired 60% or
more cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate. Therefore,
a post-treatment is carried out to remove them. The reaction
solution ({circle around (9)}) is transferred to a post-treatment
tank ({circle around (4)}) for post-treatment.
[0028] The post-treatment process will be described
hereinafter.
[0029] The post-treatment includes the processes of decomposition
of the catalyst, removal of unreacted primary alcohol and
filtration of impurities. The catalyst remaining after the
completion of the transesterification, e.g. titanate-based
catalyst, is decomposed into titanium oxide and saturated
hydrocarbon (propane, butane, etc.) upon contact with water. Thus,
a small amount of water or steam is added to the reaction solution
to decompose the catalyst.
[0030] When the catalyst is completely decomposed, the reaction
solution in the reactor is heated to 200.degree. C. or above and
the unreacted primary alcohol is completely removed under reduced
pressure ({circle around (4)}). After the unreacted primary alcohol
is removed, an adsorbent is added to the reaction solution ({circle
around (10)}) to remove suspended impurities. Further, an alkaline
adsorbent may be added to remove acidic impurities that may be
produced during the reaction. Following stirring and filtration
({circle around (5)}), purified, high-purity 60% or more
cis-di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate ({circle around
(12)}) may be obtained.
[0031] The alkaline adsorbent may be one or more selected from a
group consisting of MgO/Cl/SO.sub.4, MgO/SiO.sub.2/Cl/SO.sub.4,
MgO/Al.sub.2O.sub.3/SiO.sub.2/Cl/SO.sub.4,
MgO/Al.sub.2O.sub.3/SiO.sub.2/CO.sub.2/Cl/SO.sub.4 and hydrates
thereof. By using the alkaline adsorbent, it is possible to remove
the acidic impurities included in the 60% or more cis-dimethyl
cyclohexane-1,4-dicarboxylate used as the starting material and
remaining after the completion of the reaction, and to remove such
acidic substances as carboxylic acid generated from the hydrolysis
of the reaction product 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate by the water or steam added to
decompose the catalyst.
[0032] In addition, the acidic impurities generated due to contact
with water during the transesterification need to be removed
through a post-treatment process. When the reaction is performed by
introducing 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate as the starting material, catalyst
and primary alcohol even after the reactor is purged using steam
and then dried, a trace amount of water remains in the reactor,
which may lead to the hydrolysis of the starting material or the
reaction product, thereby increasing the acid value. Therefore, the
acidic impurities generated from the starting material need to be
removed during the reaction or post-treatment using an alkaline
adsorbent.
[0033] The 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate prepared in accordance with the
present invention includes
di(n-butyl)cyclohexane-1,4-dicarboxylate,
di(isobutyl)cyclohexane-1,4-dicarboxylate,
di(isoheptyl)cyclohexane-1,4-dicarboxylate,
di(2-ethylhexyl)cyclohexane-1,4-dicarboxylate,
di(isononyl)cyclohexane-1,4-dicarboxylate,
di(isodecyl)cyclohexane-1,4-dicarboxylate,
di(2-propylheptyl)cyclohexane-1,4-dicarboxylate, etc. The
di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate has a cis content of
60% or more, preferably 60-90%, more preferably 70-90%.
##STR00002## [0034] <cis-DMCD.fwdarw.cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate>
[0034] ##STR00003## [0035]
<trans-DMCD.fwdarw.trans-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate>
Advantageous Effects
[0036] Surprisingly, the 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate prepared in accordance with the
present invention exhibits very superior plasticizing property for
PVC resin. Further, it has superior plasticizer characteristics,
including fast plasticizer absorption for PVC resin, good product
transparency after gelling, less bleeding toward the surface upon
long-term use, and the like.
DESCRIPTION OF DRAWINGS
[0037] The above and other objects, features and advantages of the
present invention will become apparent from the following
description of preferred embodiments given in conjunction with the
accompanying drawings, in which:
[0038] FIG. 1 schematically shows the process of
transesterification.
[0039] FIG. 2 is a graph showing change of temperature during
transesterification ({circle around (a)}): Temperature of reaction
solution (FIG. 1 {circle around (1)}), ({circle around (b)})
Temperature of primary condenser (FIG. 1 {circle around (2)}),
{circle around (c)}: Temperature of gas introduced to secondary
condenser (FIG. 1 {circle around (8)})).
[0040] FIG. 3 shows GC analysis result of cis/trans contents of the
products of Example 2 and Comparative Example 2((a)1,4-DEHCH
prepared using 81% cis-DMCD, (b)1,4-DEHCH prepared using 97%
trans-DMCD).
[0041] FIG. 4 shows the change of the surface of the sheets of
Examples 4-6 and Comparative Examples 4-6 kept at 80.degree. C. for
10 days.
BEST MODE
[0042] Hereinafter, the examples and experiments will be described
to help understand the present invention. The following examples
and experiments are for illustrative purposes only and are not
intended to limit the scope of the present invention.
Example 1
Preparation of di(isononyl)cyclohexane-1,4-dicarboxylate
(1,4-DINCH)
[0043] Isononyl alcohol (8.1 mol), dimethyl
cyclohexane-1,4-dicarboxylate (DMCD, c is 81.8%, trans 18.2%, SK
NJC, 3.0 mol) and tetraisopropyl titanate catalyst (0.85 g) were
added to a 2.5 L reactor equipped with a stirrer and two condensers
and heated to 185.degree. C. Transesterification was carried out
for 6 hours under nitrogen atmosphere. Methanol, which was produced
as reaction byproduct, was evaporated inside the reactor, collected
as liquid while passing through the two condensers, and then
removed.
[0044] The transesterification was started when the temperature
reached 185.degree. C. As the methanol byproduct was produced, the
temperatures at the primary condenser and the inlet of the
secondary condenser increased rapidly [FIG. 2]. In order to reduce
the loss of isononyl alcohol while methanol was removed, the
temperature of the primary condenser was maintained at 150.degree.
C. or below and the temperature of the inlet of the secondary
condenser was maintained at 100.degree. C. or below.
[0045] Nitrogen was supplied to aid the removal of the methanol
byproduct and block the inflow of air from outside. Nitrogen was
supplied at a rate of 0.4 L/min for the first two hours following
the initiation of reaction, and at a rate of 0.8 L/min
thereafter.
[0046] After the reaction was completed, the reaction solution was
transferred to a post-treatment tank ({circle around (4)}) and
cooled to 80.degree. C. After adding deionized water (45 g), the
tetraisopropyl titanate catalyst was decomposed by strong stirring
for 5 minutes. After further adding activated carbon (0.45 g) and
an alkaline adsorbent (Kyowaad-600, Kyowa Chemical, 0.90 g),
stirring was carried out for 5 minutes. Subsequently, unreacted
isononyl alcohol was removed at 200.degree. C. under reduced
pressure using a vacuum pump. The reaction product was cooled to
120.degree. C. and filtered.
Di(isononyl)cyclohexane-1,4-dicarboxylate (cis 81%, trans 19%) was
obtained with a purity of 99.2%.
Example 2
Preparation of di(2-ethylhexyl)cyclohexane-1,4-dicarboxylate
(1,4-DEHCH)
[0047] 2-Ethylhexyl alcohol (8.1 mol), dimethyl
cyclohexane-1,4-dicarboxylate (DMCD, c is 81.8%, trans 18.2%, SK
NJC, 3.0 mol) and tetraisopropyl titanate catalyst (0.85 g) were
added to a 2.5 L reactor equipped with a stirrer and two condensers
and heated to 180.degree. C.
Di(2-ethylhexyl)cyclohexane-1,4-dicarboxylate (cis 81%, trans 19%)
was obtained with a purity of 99.3% in the same manner as in
Example 1.
Example 3
Preparation of di(2-propylheptyl)cyclohexane-1,4-dicarboxylate
(1,4-DPHCH)
[0048] 2-Propylheptyl alcohol (8.1 mol),
dimethylcyclohexane-1,4-dicarboxylate (DMCD, c is 81.8%, trans
18.2%, SK NJC, 3.0 mol) and tetraisopropyl titanate catalyst (0.85
g) were added to a 2.5 L reactor equipped with a stirrer and two
condensers and heated to 185.degree. C.
Di(2-propylheptyl)cyclohexane-1,4-dicarboxylate (cis 81%, trans
19%) was obtained with a purity of 99.3% in the same manner as in
Example 1.
Comparative Example 1
Preparation of di(isononyl)cyclohexane-1,4-dicarboxylate
[0049] Isononyl alcohol (8.1 mol),
dimethylcyclohexane-1,4-dicarboxylate (DMCD, c is 1.7%, trans
98.3%, Eastman, 3.0 mol) and tetraisopropyl titanate catalyst (0.85
g) were added to a 2.5 L reactor equipped with a stirrer and two
condensers and heated to 185.degree. C.
Di(isononyl)cyclohexane-1,4-dicarboxylate (cis 3%, trans 97%) was
obtained with a purity of 99.7% in the same manner as in Example
1.
Comparative Example 2
Preparation of di(2-ethylhexyl)cyclohexane-1,4-dicarboxylate
[0050] 2-Ethylhexyl alcohol (8.1 mol),
dimethylcyclohexane-1,4-dicarboxylate (DMCD, c is 1.7%, trans
98.3%, Eastman, 3.0 mol) and tetraisopropyl titanate catalyst (0.85
g) were added to a 2.5 L reactor equipped with a stirrer and two
condensers and heated to 180.degree. C.
Di(2-ethylhexyl)cyclohexane-1,4-dicarboxylate (cis 3%, trans 97%)
was obtained with a purity of 99.8% in the same manner as in
Example 1.
Comparative Example 3
Preparation of di(2-propylheptyl)cyclohexane-1,4-dicarboxylate
[0051] 2-Propylheptyl alcohol (8.1 mol),
dimethylcyclohexane-1,4-dicarboxylate (DMCD, c is 1.7%, trans
98.3%, Eastman, 3.0 mol) and tetraisopropyl titanate catalyst (0.85
g) were added to a 2.5 L reactor equipped with a stirrer and two
condensers and heated to 185.degree. C.
Di(2-propylheptyl)cyclohexane-1,4-dicarboxylate (cis 3%, trans 97%)
was obtained with a purity of 99.8% in the same manner as in
Example 1.
[0052] For the 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate derivatives prepared in accordance
with the present invention, a faster absorption rate in polyvinyl
chloride (PVC) resin is preferred because the time required for
mixing with PVC can be reduced. Viscosity and absorption rate in
PVC resin of the di(C4-C20)alkyl cyclohexane-1,4-dicarboxylate
derivatives prepared in Examples 1 to 3 and Comparative Examples 1
to 3 depending on cis/trans contents are summarized in Table 1. The
plasticizer absorption rate was evaluated by comparatively
measuring the times required for the plasticizer to be completely
absorbed in PVC resin (P-1000, Hanwha Chemical). A planetary mixer
(Brabender) was used for the measurement. After adding 400 g of
P-1000 resin in the mixer maintained at 80.degree. C., the resin
temperature was uniformly increased to 80.degree. C. while
stirring. Subsequently, 50 phr of the plasticizer was added to the
resin, which was being stirred. With the addition of the
plasticizer, the load of the mixer blade increases. However, as the
plasticizer is absorbed, the powder fluidity increases and the load
decreases gradually. The plasticizer absorption rate was evaluated
by measuring the time ranging from the point where the load began
to increase to the point where it decreased.
TABLE-US-00001 TABLE 1 Cis 81%, trans 19% Cis 3%, trans 97% Vis-
Absorption Vis- Absorption cosity rate in PVC Comparative cosity
rate in PVC Examples (25.degree. C.) resin Examples (25.degree. C.)
resin 1,4- 40 cP 412 sec 1,4-DINCH 43 cP 648 sec DINCH (Comp. (Ex.
1) Ex. 1) 1,4- 28 cP 270 sec 1,4-DEHCH 30 cP 338 sec DEHCH (comp.
(Ex. 2) Ex. 2) 1,4- 44 cP 782 sec 1,4-DPHCH 48 cP 836 sec DPHCH
(Comp. (Ex. 3) Ex. 3)
[0053] As seen in Table 1, the higher the cis content was, the
lower the viscosity was and the faster the absorption rate in PVC
resin was. That is, the high-cis plasticizer according to the
present invention exhibits very superior processability and
absorption rate in PVC resin.
Examples 4-6 and Comparative Examples 4-6
Comparison of Performance as Plasticizer (I)
[0054] In order to compare the performance of di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate derivatives prepared in accordance
with the present invention as plasticizer depending on cis/trans
contents, PVC blends were prepared with the compositions and mixing
proportions presented in Table 2. 0.8 mm sheets were formed by
uniformly mixing in a mixing roll maintained at 160.degree. C. for
4 minutes.
[0055] Thus prepared three sheets were stacked and pressed for 10
minutes using a press forming machine at 180.degree. C. 2 mm-thick,
transparent, soft PVC sheets were obtained.
TABLE-US-00002 TABLE 2 (Unit: parts by weight) Ex. 4 Ex. 5 Ex. 6
Comp. Ex. 4 Comp. Ex. 5 Comp. Ex. 6 PVC resin (P-1000) 100 100 100
100 100 100 Plasticizer cis 81%, 1,4-DINCH 50 -- -- -- -- -- trans
19% (Ex. 1) 1,4-DEHCH -- 50 -- -- -- -- (Ex. 2) 1,4-DPHCH -- -- 50
-- -- -- (Ex. 3) cis 3%, 1,4-DINCH -- -- -- 50 -- -- trans 97%
(Comp. Ex. 1) 1,4-DEHCH -- -- -- -- 50 -- (Comp. Ex. 2) 1,4-DPHCH
-- -- -- -- -- 50 (Comp. Ex. 3) KBZ-290G 2.5 2.5 2.5 2.5 2.5 2.5
E-700 2.0 2.0 2.0 2.0 2.0 2.0 P-1000: PVC resin (Hanwha Chemical)
KBZ-290G: Ba/Zn-based PVC stabilizer (Kolon Petrochemical) E-700:
Epoxylated soybean oil stabilizer (Songwon Industrial)
[0056] In order to compare the degree of effluence of the
plasticizer to the sheet surface, the transparent sheets obtained
above were kept at 80.degree. C. for 10 days and the sheet surface
was observed using a microscope. As seen in FIG. 4, staining due to
the effluence of the plasticizer to the sheet surface was severer
as the number of carbon atoms of the primary alcohol increased
(C8<C9<C10). The degree of effluence was much severer in
high-trans sheets (Comparative Examples 4, 5 and 6) than in the
high-cis sheets (Examples 4, 5 and 6). Particularly, the difference
was larger as the number of carbon atoms increased. For soft PVC
products including a plasticizer to maintain appropriate properties
and qualities for a long period of time, they should have good
durability with no quality change and plasticizer effluence under
various use environments. It was confirmed that high-cis
plasticizers are more adequate than high-trans plasticizers, in
this regard.
[0057] The change of bleeding at the sheet surface of the PVC
sheets of Examples 4-6 and Comparative Examples 4-6 depending on
cis/trans contents was measured by light transmittance and haze.
Light transmittance and haze were measured using Haze-Gard Plus
(BYK Gardner).
[0058] The PVC sheets prepared in Examples 4-6 and Comparative
Examples 4-6 were kept at 80.degree. C. for 10 days, and the change
of light transmittance and haze was measured. The result is given
in Table 3.
TABLE-US-00003 TABLE 3 Plasticizer cis 81%, trans 19% cis 3%, trans
97% 1,4-DINCH 1,4-DEHCH 1,4-DPHCH 1,4-DINCH 1,4-DEHCH 1,4-DPHCH
Sheet Ex. 4 Ex. 5 Ex. 6 Comp. Ex. 4 Comp. Ex. 5 Comp. Ex. 6 Light
Before 92.3 92.8 91.8 92.2 92.7 90.5 transmittance After 81.1 83.7
76.0 78.6 81.9 71.9 (%) Haze (%) Before 0.77 0.56 1.36 0.77 0.65
2.86 After 2.65 1.38 7.87 11.00 1.71 5.17
[0059] As seen in Table 3, the higher the cis content, the higher
is the light transmittance and the lower the haze. Before heat
treatment, the light transmittance of the transparent sheet was
similar (91-92%) without regard to the primary alcohol or the
cis/trans contents of the cyclohexane-1,4-dicarboxylate
derivatives. The haze of the sheet was also in the range from 0.5
to 2.9%. After the treatment at 80.degree. C. for 10 days, the
light transmittance of the high-cis samples (Examples 4-6)
decreased to 76-84%, whereas that of the high-trans samples
(Comparative Examples 4-6) decreased more to 72-82%. The change of
haze showed a similar pattern to that of the light transmittance.
Especially, Comparative Example 6 showed a low haze of 5.17%, which
was due to the formation of an oily film on the sheet surface
caused by the bleeding of the plasticizer.
[0060] The softness of the PVC sheets of Examples 4-6 and
Comparative Examples 4-6 was measured using a durometer. The higher
the plasticizing effect of the plasticizer for PVC resin, the
softer is the sheet and the lower the hardness. The hardness of the
sheet was measured based on the Shore A scale. The result is given
in Table 4. For the same di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate derivatives, the high-cis derivatives
(Examples 4-6) exhibited a plasticizing effect 1.7-4.5% better than
the high-trans derivatives (Comparative Examples 4-6). A better
plasticizing effect provides advantages in use because the same
softness can be obtained with less amount.
TABLE-US-00004 TABLE 4 Hardness (Shore A) of PVC samples depending
on cis/trans contents Examples Ex. 4 Ex. 5 Ex. 6 cis 81%, trans 19%
1,4-DINCH 1,4-DEHCH 1,4-DPHCH 85.5 82.0 87.5 Comparative Examples
Comp. Ex. 4 Comp. Ex. 5 Comp. Ex. 6 cis 3%, trans 97% 1,4-DINCH
1,4-DEHCH 1,4-DPHCH 89.5 84.5 89.0 Difference of hardness 4.5% 3.0%
1.7%
Examples 7-9 and Comparative Examples 7-9
Comparison of Performance as Plasticizer (II)
[0061] In order to compare the performance of the di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate derivatives prepared in accordance
with the present invention as plasticizer for paste PVC resin
depending on cis/trans contents, PVC resin and additives were mixed
as in Table 5. Physical properties, gelling property and foaming
property of the resultant paste sols were compared in Table 6.
TABLE-US-00005 TABLE 5 Composition Ex. 7 Ex. 8 Ex. 9 Comp. Ex. 7
Comp. Ex. 8 Comp. Ex. 9 Paste resin (EL-103) 100 100 100 100 100
100 Plasticizer cis 81%, 1,4-DINCH 70 -- -- -- -- -- trans 19% (Ex.
1) 1,4-DEHCH -- 70 -- -- -- -- (Ex. 2) 1,4-DPHCH -- -- 70 -- -- --
(Ex. 3) cis 3%, 1,4-DINCH -- -- -- 70 -- -- trans 97% (Comp. Ex. 1)
1,4-DEHCH -- -- -- -- 70 -- (Comp. Ex. 2) 1,4-DPHCH -- -- -- -- --
70 (Comp. Ex. 3) CNA070 3.0 3.0 3.0 3.0 3.0 3.0 DWPX03MB 2.0 2.0
2.0 2.0 2.0 2.0 TiO.sub.2 10 10 10 10 10 10 OM-10 90 90 90 90 90 90
BYK-5110 3.0 3.0 3.0 3.0 3.0 3.0 CNA070: Na/Zn-based PVC stabilizer
(CNA) DWPX03MB: ADCA-based foaming agent (Dongjin Semichem) OM-10:
Calcium carbonate (Omiya Korea) BYK-5110: Viscosity reducing agent
(BYK)
TABLE-US-00006 TABLE 6 Plasticizer cis 81%, trans 19% cis 3%, trans
97% 1,4-DINCH 1,4-DEHCH 1,4-DPHCH 1,4-DINCH 1,4-DEHCH 1,4-DPHCH
Sheet Ex. 7 Ex. 8 Ex. 9 Comp. Ex. 7 Comp. Ex. 8 Comp. Ex. 9 Sol
viscosity 3,850 3,450 3,700 4,350 3,500 4,300 Gelling property
.DELTA. .largecircle. .DELTA. .DELTA. .largecircle. .DELTA. Foaming
property .DELTA. .largecircle. .DELTA. .DELTA. .largecircle.
.DELTA. .largecircle.: good, .DELTA.; moderate, X: poor
[0062] The paste sols prepared using high-cis plasticizers
(Examples 7-9) had a lower viscosity than the sols prepared using
high-trans plasticizers (Comparative Examples 7-9). Thus, they
exhibited better forming workability, processability, and the like.
Gelling property and foaming property were comparable.
[0063] The present application contains subject matter related to
Korean Patent Application Nos. 10-2008-0101629 and 10-2009-0063075,
filed in the Korean Intellectual Property Office on Oct. 16, 2008
and Jul. 10, 2009, the entire contents of which are incorporated
herein by reference.
[0064] While the present invention has been described with respect
to the specific embodiments, it will be apparent to those skilled
in the art that various changes and modifications may be made
without departing from the spirit and scope of the invention as
defined in the following claims.
INDUSTRIAL APPLICABILITY
[0065] The method for preparing 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate according to the present invention is
economical because no hydrogenation process is required. The
methanol byproduct produced during the transesterification can be
easily removed because it has a low boiling point. The reaction
proceeds fast, and no neutralization treatment is required for
removal of unreacted materials after completion of the reaction.
Since the side reactions are prevented, the product can be obtained
with high purity. In addition, since a post-treatment process is
simply performed by filtering off impurities by adsorption without
generation of waste water, the process is environment-friendly.
Therefore, highly pure 60% or more cis-di(C4-C20)alkyl
cyclohexane-1,4-dicarboxylate can be prepared through a simple and
commercial-scale process. Further, the recovered methanol can be
recycled for the preparation of 60% or more cis-dimethyl
cyclohexane-1,4-dicarboxylate or for other purposes through a
simple purification process.
* * * * *