U.S. patent application number 15/026656 was filed with the patent office on 2016-08-18 for branched polyarylene sulfide resin, method for manufacturing same and use as polymer modifier.
The applicant listed for this patent is Kureha Corporation. Invention is credited to Akihiro KONNO, Yasuhiro SUZUKI.
Application Number | 20160237216 15/026656 |
Document ID | / |
Family ID | 52778644 |
Filed Date | 2016-08-18 |
United States Patent
Application |
20160237216 |
Kind Code |
A1 |
KONNO; Akihiro ; et
al. |
August 18, 2016 |
BRANCHED POLYARYLENE SULFIDE RESIN, METHOD FOR MANUFACTURING SAME
AND USE AS POLYMER MODIFIER
Abstract
Disclosed is a branched polyarylene sulfide resin including an
--S-- substituent group with a cleaved disulfide compound which has
a melt viscosity as measured at a halogen content of 4,000 ppm or
less, a temperature of 330.degree. C. and a shear rate of 2
sec.sup.-1 of 1.0.times.10.sup.4 to 50.0.times.10.sup.4 Pas and a
melt viscoelasticity tan .delta. as measured at a temperature of
310.degree. C. and an angular velocity of 1 rad/sec of 0.1 to
0.6.
Inventors: |
KONNO; Akihiro; (Tokyo,
JP) ; SUZUKI; Yasuhiro; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kureha Corporation |
Tokyo |
|
JP |
|
|
Family ID: |
52778644 |
Appl. No.: |
15/026656 |
Filed: |
September 26, 2014 |
PCT Filed: |
September 26, 2014 |
PCT NO: |
PCT/JP2014/075611 |
371 Date: |
April 1, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08G 75/02 20130101;
C08G 75/0231 20130101; C08G 75/0259 20130101; C08G 75/0213
20130101 |
International
Class: |
C08G 75/0231 20060101
C08G075/0231; C08G 75/0213 20060101 C08G075/0213; C08G 75/0259
20060101 C08G075/0259 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 2013 |
JP |
2013-206849 |
Claims
1. A branched polyarylene sulfide resin comprising an --S--
substituent group with a cleaved disulfide compound, wherein the
resin has the following characteristics i to iii: i) a halogen
content of 4,000 ppm or less; ii) a melt viscosity as measured at a
temperature of 330.degree. C. and a shear rate of 2 sec.sup.-1 of
1.0.times.10.sup.4 to 50.0.times.10.sup.4 Pas; and iii) a melt
viscoelasticity tan .delta. as measured at a temperature of
310.degree. C. and an angular velocity of 1 rad/sec of 0.1 to
0.6.
2. The branched polyarylene sulfide resin according to claim 1,
wherein the halogen is chlorine.
3. The branched polyarylene sulfide resin according to claim 2,
wherein the chlorine content is 2,000 ppm or less.
4. The branched polyarylene sulfide resin according to claim 1,
wherein the disulfide compound is diphenyl disulfide.
5. A method for manufacturing a branched polyarylene sulfide resin
including an --S-- substituent group with a cleaved disulfide
compound that polymerizes a sulfur source with a dihalo aromatic
compound in an organic amide solvent in the presence of a disulfide
compound and a polyhalo aromatic compound having three or more
halogen substituent groups in the molecule, the method comprising
the steps of: performing a polymerization reaction of a sulfur
source with a dihalo aromatic compound in an organic amide solvent
using the dihalo aromatic compound in an amount of from 0.95 to
1.02 mol per mol of sulfur source; adding a disulfide compound in
an amount of from 0.001 to 0.03 mol per mol of sulfur source during
the time interval between a stage when the conversion ratio of the
dihalo aromatic compound is 0% and a stage when a polyhalo aromatic
compound is added and reacting the mixture; adding a polyhalo
aromatic compound, in an amount of from 0.002 to 0.06 mol per mol
of sulfur source and an amount of from 0.2 to 12 mol per mol of
disulfide compound, to the polymerization reaction mixture at a
stage when the conversion ratio of the dihalo aromatic compound
reaches 80% or more; and performing a phase separation
polymerization reaction in the presence of a phase separation
agent.
6. The manufacturing method according to claim 5, further
comprising the steps of: (1) heating a mixture containing an
organic amide solvent, a sulfur source including an alkali metal
hydrosulfide and an alkali metal hydroxide, and discharging at
least part of the distillate containing water from the inside of
the system containing the mixture to the outside of the system
(dehydration step 1); (2) mixing the mixture remaining inside the
system in the dehydration step 1 with a dihalo aromatic compound to
prepare a charged mixture containing an organic amide solvent, a
sulfur source (hereinafter, referred to as "charged sulfur
source"), an alkali metal hydroxide, water and a dihalo aromatic
compound, wherein the amount of the dihalo aromatic compound in the
charged mixture is from 0.95 to 1.02 mol per mol of charged sulfur
source (charging step 2); (3) heating the charged mixture to a
temperature of from 170 to 270.degree. C. and performing a
polymerization reaction of the charged sulfur source and the dihalo
aromatic compound in a water-containing organic amide solvent,
adding a disulfide compound in an amount of from 0.001 to 0.03 mol
per mol of charged sulfur source during the time interval between a
stage when the conversion ratio of the dihalo aromatic compound is
0% and a stage when a polyhalo aromatic compound is added and
reacting the mixture, adding a polyhalo aromatic compound (in an
amount of from 0.002 to 0.06 mol per mol of charged sulfur source
and an amount of from 0.2 to 12 mol per mol of disulfide compound)
to the polymerization reaction mixture at a stage when the
conversion ratio of the dihalo aromatic compound reaches 80% or
greater and performing a polymerization reaction (prestage
polymerization step 3); and (4) heating the polymerization reaction
mixture to a temperature of 240.degree. C. or higher and performing
a phase separation polymerization reaction at a temperature of from
240 to 290.degree. C. in the presence of a phase separation agent
(poststage polymerization step 4).
7. The manufacturing method according to claim 5, wherein the total
of the halogen content in the dihalo aromatic compound and the
halogen content in the polyhalo aromatic compound is from 1.01 to
1.05 mol per mol of charged sulfur source.
8. The manufacturing method according to claim 6, wherein when the
conversion ratio of the dihalo aromatic compound in the prestage
polymerization step 3 reaches 80% or greater, a phase separation
agent is added.
9. Use of the branched polyarylene sulfide resin according to claim
1 as a polymer modifier.
10. The use according to claim 9, wherein the use of the branched
polyarylene sulfide resin as the polymer modifier is use as a burr
suppressor with respect to a linear polyarylene sulfide resin.
Description
TECHNICAL FIELD
[0001] The present invention relates to a branched polyarylene
sulfide resin including an --S-- substituent group with a cleaved
disulfide compound and a method for manufacturing the same. More
particularly, the present invention relates to a branched
polyarylene sulfide resin including an --S-- substituent group with
a cleaved disulfide compound which can solve problems of corrosion
to a metal mold due to halogen and environmental problems and
provide a molded product with significantly suppressed burrs (which
are problematic during molding processing) when used as a burr
suppressor and which has highly balanced characteristics of the
halogen content, the melt viscosity and the melt viscoelasticity
tan .delta. and a method for manufacturing the same. Further, the
present invention relates to use of the branched polyarylene
sulfide resin as a polymer modifier.
BACKGROUND ART
[0002] Polyarylene sulfide resins (hereinafter abbreviated as "PAS
resin"), representative examples of which polyphenylene sulfide
resins (hereinafter abbreviated as "PPS resin"), are engineering
plastics exhibiting excellent heat resistance, chemical resistance,
flame retardancy, mechanical strength, characteristics, dimensional
stability, and the like. The PAS resin can be formed into various
molded products such as films, sheets and fibers by a general melt
molding method such as injection molding, extrusion molding or
compression molding. Thus, the resin is widely used as a material
for resin parts in a wide range of fields including electrical and
electric devices, automobile devices and chemical devices.
[0003] A known example of a representative method for manufacturing
a PAS resin is a method of reacting a sulfur source and a dihalo
aromatic compound in an organic amide solvent such as
N-methyl-2-pyrrolidone (hereafter abbreviated as "NMP"). A PAS
resin obtained by this method typically tends to have a structure
in which a halogen bonds to the terminal of a polymer and therefore
has a high halogen content, even when sufficiently washed in the
separation and recovery step after a polymerization reaction. When
such a PAS resin having a high halogen content is used, the
corrosion to a metal mold during molding processing as described
above or environmental pollution as evidenced by halogen
regulations become problems. Further, since the manufacturing
conditions of the PAS resin are wide ranging, it is difficult to
adjust the conditions. Particularly, it is difficult to achieve a
balance between processability or fusion characteristics and burr
suppressing characteristics during injection molding. There is a
disadvantage in that the amount of burrs generated during injection
molding is large. The term "burr" means a portion of a molding
material which enters the space between the two parts of a metal
mold and solidifies. It is necessary to remove the burr which is
solidified into a thin film or flake and attached to a molded
product in a finishing step.
[0004] In order to reduce the halogen content of the PAS resin, the
PAS resin is conventionally washed with high temperature water or
an organic solvent in the separation and recovery step after the
polymerization reaction. Examples of the organic solvent include
the same organic amide solvent as the polymerization solvent,
ketones (e.g., acetone) and alcohols (e.g., methanol). Thus, in
order to reduce the halogen content of the PAS resin, the halogen
content has always been reduced by washing.
[0005] On the other hand, a method for adding a branched PAS resin
to a linear PAS resin is suggested to suppress generation of burrs
during injection molding.
[0006] The following has been reported in Japanese Patent No.
5189293: when a branched PAS resin is manufactured by a method
including the steps of: reacting a sulfur source with a dihalo
aromatic compound in an organic amide solvent; and adding a
polyhalo aromatic compound having three or more halogen substituent
groups to the polymerization reaction mixture at a predetermined
ratio at a stage when the conversion ratio of the dihalo aromatic
compound becomes sufficiently high, a branched PAS resin in which
all the melt viscosity, average particle size and melt
viscoelasticity tan .delta. are within an appropriate range can be
obtained. For example, when the branched PAS resin is blended with
a linear PAS resin, an effect as a burr suppressor is exerted and
further the surface properties of the molded product are
improved.
[0007] However, although a PAS resin having a low halogen content
and excellent characteristics of suppressing generation of burrs
has been earnestly developed, a target resin having such
characteristics has not currently been obtained. In the field of
the PAS resin, there is a daily increasing demand for the
above-described characteristics. The present inventors have
developed and studied to satisfy the demand for improvement.
CITATION LIST
Patent Literature
[0008] Patent Document 1: Japanese Patent No. 5189293B
(corresponding to EP 1837359 A1)
SUMMARY OF INVENTION
Technical Problem
[0009] An object of the present invention is to provide a branched
PAS resin including an --S-- substituent group with a cleaved
disulfide compound which has a low halogen (chlorine) content when
blended with a thermoplastic resin such as a linear PAS resin as a
polymer modifier, is excellent in corrosion resistance to a metal
mold, is able to clear environmental regulations, significantly
suppresses generation of burrs, and has highly balanced
characteristics of the halogen content, the melt viscosity and the
melt viscoelasticity tan .delta. and a method for manufacturing the
same.
[0010] The branched PAS resin including an --S-- substituent group
with a cleaved disulfide compound of the present invention is a
granular resin having excellent thermal stability and
processability.
[0011] Further, the branched PAS resin including an --S--
substituent group with a cleaved disulfide compound of the present
invention has a low halogen content, but it produces an effect as a
burr suppressor in a region of a wide range of melt viscosity and
melt viscoelasticity (tan .delta.).
[0012] Furthermore, the branched PAS resin including an --S--
substituent group with a cleaved disulfide compound of the present
invention has a low halogen content, but it produces an effect as a
burr suppressor even in a region of low melt viscosity and high
melt viscoelasticity (tan .delta.), and thus it exerts an effect of
improving surface properties of the molded product.
[0013] The present inventors have focused on the introduction of a
branched structure to a PAS resin, cleavage of an --S--S-- portion
of a disulfide compound and substitution capability of the cleaved
compound for the terminals of the PAS polymer in order to increase
the performance and solve problems on the halogen (chlorine)
content (namely, environmental regulations on halogen, problems of
corrosion resistance to a metal mold and the like) by using the
conventional branched PAS resin as a polymer modifier, and
conceived a method for manufacturing a branched PAS resin in which
the polymerization reaction conditions are highly controlled.
[0014] Hence, they have conceived a method for manufacturing a
branched PAS resin including the steps of: performing a
polymerization reaction of a sulfur source with a dihalo aromatic
compound in an organic amide solvent using the dihalo aromatic
compound in an amount of from 0.95 to 1.02 mol per mol of sulfur
source; adding a disulfide compound in an amount of from 0.001 to
0.03 mol per mol of sulfur source during the time interval between
a stage when the conversion ratio of the dihalo aromatic compound
is 0% and a stage when a polyhalo aromatic compound is added and
reacting the mixture; adding a polyhalo aromatic compound (in an
amount of from 0.002 to 0.06 mol per mol of sulfur source and an
amount of from 0.2 to 12 mol per mol of disulfide compound) to the
polymerization reaction mixture at a stage when the conversion
ratio of the dihalo aromatic compound reaches 80% or greater; and
performing a phase separation polymerization reaction in the
presence of a phase separation agent.
[0015] The manufacturing method of the present invention is divided
into the following three important points: That is, the points
include (a) performing a polymerization reaction of a sulfur source
with a dihalo aromatic compound in an organic amide solvent using
the dihalo aromatic compound in an amount of from 0.95 to 1.02 mol
per mol of sulfur source; (b) adding a disulfide compound in an
amount of from 0.001 to 0.03 mol per mol of sulfur source during
the time interval between a stage when the conversion ratio of the
dihalo aromatic compound is 0% and a stage when a polyhalo aromatic
compound is added and reacting the mixture; and (c) adding a
polyhalo aromatic compound (in an amount of from 0.002 to 0.06 mol
per mol of sulfur source and an amount of from 0.2 to 12 mol per
mol of disulfide compound) to the polymerization reaction mixture
at a stage when the conversion ratio of the dihalo aromatic
compound reaches 80% or greater and performing a phase separation
polymerization reaction in the presence of a phase separation
agent.
[0016] The first step of "(a) performing a polymerization reaction
of a sulfur source with a dihalo aromatic compound in an organic
amide solvent using the dihalo aromatic compound in an amount of
from 0.95 to 1.02 mol per mol of sulfur source" provides an effect
resulting in control of melt viscosity based on the adjustment of
molecular weight, reduction of the halogen (chlorine) content by
decreasing the number of polymer terminals having halogen
(chlorine) and facilitation of the reaction of the disulfide
compound and/or the polyhalo aromatic compound in the
polymerization reaction field.
[0017] As a result, a branched PAS resin having a wide estimated
range of melt viscosity, low halogen (chlorine) content and
excellent processability is obtained.
[0018] An object of the second step of "(b) adding a disulfide
compound in an amount of from 0.001 to 0.03 mol per mol of sulfur
source during the time interval between a stage when the conversion
ratio of the dihalo aromatic compound is 0% and a stage when a
polyhalo aromatic compound is added and reacting the mixture" is to
modify some terminals of a PAS in the middle of the polymerization
so as to include an --S-- substituent group with a cleaved
disulfide compound.
[0019] Thus, when some terminals of the PAS in the middle of the
polymerization are modified so as to include an --S-- substituent
group with a cleaved disulfide compound, the terminals play no role
in the subsequent growth. Consequently, an effect resulting in
reduction of molecular weight of the PAS is given and an effect
resulting in reduction of melt viscosity is eventually given.
[0020] At the same time, the halogen (chlorine) at the terminal is
converted to an --S-- substituent group, and thus an effect
resulting in control of a branched state or reduction of the
halogen (chlorine) content is given.
[0021] In order to maximize the object and effects, it is important
to strictly adjust the ratio of the disulfide compound to the
sulfur source and the addition stage of the disulfide compound and
to adjust the ratio of the dihalo aromatic compound to the sulfur
source in the first step.
[0022] The third step of "(c) adding a polyhalo aromatic compound
(in an amount of from 0.002 to 0.06 mol per mol of sulfur source
and an amount of from 0.2 to 12 mol per mol of disulfide compound)
to the polymerization reaction mixture at a stage when the
conversion ratio of the dihalo aromatic compound reaches 80% or
greater and performing a phase separation polymerization reaction
in the presence of a phase separation agent" is a step of
introducing a branched structure using a polyhalo aromatic compound
as described above.
[0023] However, this step is different from the conventional step.
In terms of the fact that a PAS including an --S-- substituent
group where a disulfide compound is cleaved at the terminals is
polymerized into a branched structure, this step differs from the
conventional step of introducing a branched structure.
[0024] That is, the method for manufacturing a branched PAS resin
of the present invention has characteristics in that, in addition
to a polymerization reaction with a dihalo aromatic compound, a
reaction with a disulfide compound and a reaction with a polyhalo
aromatic compound are carried out in the polymerization reaction
field.
[0025] Therefore, in order to introduce the branched structure
targeted by the present invention, the key points are as follows:
the ratio of the polyhalo aromatic compound to the sulfur source
and the adjustment of the addition stage as well as the ratio of
the polyhalo aromatic compound to the disulfide compound and
particularly the adjustment of the ratio of the dihalo aromatic
compound to the sulfur source in the first step.
[0026] In the reaction of the polyhalo aromatic compound to
introduce a branched structure into the PAS resin, it is important
to form a liquid-liquid phase separation state in which a produced
polymer dense phase and a produced polymer dilute phase are both
present in a liquid phase in the polymerization reaction system as
the polymerization reaction field by using the phase separation
agent. Such a polymerization reaction in a liquid-liquid phase
separation state is also called "phase separation polymerization
reaction".
[0027] In this produced polymer dense phase, the reaction of the
polyhalo aromatic compound mainly proceeds and the bonding of the
polymers increases the molecular weight. Thus, a branched PAS resin
having a target melt viscosity is formed.
[0028] The branched PAS resin has characteristics in that the
halogen (chlorine) content is reduced by the bonding effect of the
polymers and further a granular PAS resin is obtained.
[0029] The branched PAS resin thus polymerized includes an --S--
substituent group where a disulfide compound is cleaved at some of
the terminals of the polymer.
[0030] Consequently, in the branched PAS resin polymerized in this
step, it is possible to make the halogen (chlorine) content low,
and it is possible to rationalize the melt viscosity and it is
possible realize a wider range of numerical value of melt
viscoelasticity tan .delta. which is an indicator of branched
structure. Further, it is possible to obtain a branched PAS resin
in a granular form.
[0031] Thus, the manufacturing method of the present invention can
provide a branched PAS resin having a highly balanced and
appropriate range of (i) the halogen (chlorine) content, (ii) the
melt viscosity and (iii) the branched structure (melt
viscoelasticity tan .delta. as an indicator).
[0032] For example, in Working Example 4 described below, the
halogen (chlorine) content is as low as 1,650 ppm, the melt
viscoelasticity tan .delta. as measured at a temperature of
310.degree. C. and an angular velocity of 1 rad/sec is 0.55 and the
melt viscosity as measured at a temperature of 330.degree. C. and a
shear rate of 2 sec.sup.-1 is as remarkably low as 45,000 Pas.
Nevertheless, a burr suppressing effect is produced.
[0033] According to the manufacturing method of the present
invention, it is possible to obtain a branched PAS resin including
an --S-- substituent group with a cleaved disulfide compound which
has such excellent characteristics. The present invention has been
completed based on these findings.
Solution to Problem
[0034] Thus, according to the present invention, there is provided
a branched polyarylene sulfide resin including an --S-- substituent
group with a cleaved disulfide compound, wherein the resin has the
following characteristics i to iii:
i) a halogen content of 4,000 ppm or less; ii) a melt viscosity as
measured at a temperature of 330.degree. C. and a shear rate of 2
sec' of 1.0.times.10.sup.4 to 50.0.times.10.sup.4 Pas; and iii) a
melt viscoelasticity tan .delta. as measured at a temperature of
310.degree. C. and an angular velocity of 1 rad/sec of 0.1 to
0.6.
[0035] Further, according to the present invention, there is
provided a method for manufacturing a branched polyarylene sulfide
resin including an --S-- substituent group with a cleaved disulfide
compound that polymerizes a sulfur source with a dihalo aromatic
compound in an organic amide solvent in the presence of a disulfide
compound and a polyhalo aromatic compound having three or more
halogen substituent groups in the molecule, the method including
the steps of: performing a polymerization reaction of a sulfur
source with a dihalo aromatic compound in an organic amide solvent
using the dihalo aromatic compound in an amount of from 0.95 to
1.02 mol per mol of sulfur source; adding a disulfide compound in
an amount of from 0.001 to 0.03 mol per mol of sulfur source during
the time interval between a stage when the conversion ratio of the
dihalo aromatic compound is 0% and a stage when a polyhalo aromatic
compound is added and reacting the mixture; adding a polyhalo
aromatic compound (in an amount of from 0.002 to 0.06 mol per mol
of sulfur source and an amount of from 0.2 to 12 mol per mol of
disulfide compound) to the polymerization reaction mixture at a
stage when the conversion ratio of the dihalo aromatic compound
reaches 80% or more; and performing a phase separation
polymerization reaction in the presence of a phase separation
agent.
[0036] Furthermore, according to the present invention, there is
provided use of a branched PAS resin including an --S-- substituent
group with a cleaved disulfide compound as a polymer modifier.
[0037] Further, according to the present invention, there is
provided use wherein the use of a branched PAS resin including an
--S-- substituent group with a cleaved disulfide compound as a
polymer modifier is use as a burr suppressor with respect to a
linear PAS resin.
[0038] The term "branched PAS resin including an --S-- substituent
group with a cleaved disulfide compound" used herein (hereinafter,
sometimes simply referred to as "branched PAS resin") means a PAS
resin in which some terminals of a PAS in the middle of the
polymerization are modified by a reaction of the PAS in the middle
of the polymerization with a disulfide compound before introduction
of a branched structure in the polymerization step and then the
branched structure is introduced. The PAS resin into which the
branched structure of the present invention is introduced
preferably includes no crosslinked structure, but may include a
small amount of a crosslinked structure which is a byproduct formed
by the polymerization reaction.
[0039] The term "linear PAS resin" used herein means a PAS resin
having a substantially linear structure. The linear PAS resin of
the present invention may include a small amount of a branched or
crosslinked structure.
Advantageous Effect of Invention
[0040] In the branched PAS resin including an --S-- substituent
group with a cleaved disulfide compound of the present invention,
the halogen (chlorine) content is low, and it is possible to
rationalize the melt viscosity and it is possible to realize a
wider range of numerical value of melt viscoelasticity tan .delta.
which is an indicator of branched structure. The branched PAS resin
including an --S-- substituent group with a cleaved disulfide
compound of the present invention can significantly suppress
generation of burrs, reduce the halogen content, and solve
environmental problems (low halogenation) and problems of corrosion
to a metal mold, when blended with a thermoplastic resin such as a
linear PAS resin as the polymer modifier. Further, the branched PAS
resin including an --S-- substituent group with a cleaved disulfide
compound of the present invention is a granular resin excellent in
thermal stability and processability.
DESCRIPTION OF EMBODIMENTS
1. Sulfur Source
[0041] In the present invention, an alkali metal sulfide or an
alkali metal hydrosulfide or a mixture thereof is used as a sulfur
source. Also, a hydrogen sulfide may be used as the sulfur
source.
[0042] It is preferable to use a sulfur source which contains an
alkali metal hydrosulfide or an alkali metal hydrosulfide as a main
component. Examples of the alkali metal hydrosulfide include
lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide,
rubidium hydrosulfide, cesium hydrosulfide, and a mixture of two or
more kinds thereof, but are not particularly limited thereto. The
alkali metal hydrosulfide may be used in any form of an anhydride,
a hydrate and an aqueous solution. Among them, sodium hydrosulfide
and lithium hydrosulfide are preferred from the viewpoint of being
industrially available at low cost. The alkali metal hydrosulfide
is preferably used as an aqueous mixture (i.e., a mixture with
water having fluidity) from the viewpoint of treatment operation,
metering, and the like.
[0043] In the step of manufacturing alkali metal hydrosulfide, a
small amount of a byproduct of alkali metal sulfide is generally
formed. The alkali metal hydrosulfide used in the present invention
may contain a small amount of alkali metal sulfide. The alkali
metal hydrosulfide tends to be stable when it contains a small
amount of alkali metal sulfide.
[0044] When the sulfur source is a mixture of alkali metal
hydrosulfide and alkali metal sulfide, the composition includes 70
to 100 mol % of alkali metal hydrosulfide and 0 to 30 mol % of
alkali metal sulfide, preferably 90 to 99.8 mol % of alkali metal
hydrosulfide and 0.2 to 10 mol % of alkali metal sulfide, more
preferably 93 to 99.7 mol % of alkali metal hydrosulfide % and 0.3
to 7 mol % of alkali metal sulfide, and even more preferably 95 to
99.6 mol % of alkali metal hydrosulfide % and 0.4 to 5 mol % of
alkali metal sulfide, from the viewpoint of the stability of the
polymerization reaction system.
[0045] When the sulfur source is a mixture of alkali metal
hydrosulfide and alkali metal sulfide, the total molar amount of
alkali metal hydrosulfide and alkali metal sulfide is a molar
amount of the charged sulfur source (sometimes referred to as
"effective sulfur source"). Further, the total molar amount is a
molar amount of the charged sulfur source after the dehydration
step in the case of inserting the dehydration step prior to the
preparation step.
[0046] Examples of the alkali metal sulfide include lithium
sulfide, sodium sulfide, potassium sulfide, rubidium sulfide,
cesium sulfide, and a mixture of two or more kinds thereof, but are
not particularly limited thereto. The alkali metal sulfide may be
used in any form of an anhydride, a hydrate and an aqueous
solution. Among them, sodium sulfide is preferred from the
viewpoint of being industrially available at low cost and easily
handled.
2. Alkali Metal Hydroxide
[0047] In the manufacturing method of the present invention, it is
preferable to employ a method for polymerizing a sulfur source
containing an alkali metal hydrosulfide and a dihalo aromatic
compound in a water-containing organic amide solvent in the
presence of alkali metal hydroxide.
[0048] Examples of the alkali metal hydroxide include lithium
hydroxide, sodium hydroxide, potassium hydroxide, rubidium
hydroxide, cesium hydroxide and a mixture of two or more kinds
thereof, but are not particularly limited thereto. Among them,
sodium hydroxide is preferred from the viewpoint of being
industrially available at low cost. The alkali metal hydroxide is
preferably used as an aqueous mixture (i.e., a mixture with water
having fluidity) from the viewpoint of handling property, such as
metering.
3. Dihalo Aromatic Compound
[0049] The dihalo aromatic compound used in the present invention
is a dihalogenated aromatic compound having two halogen atoms
directly bonded to the aromatic ring. Specific examples of the
dihalo aromatic compound include o-dihalobenzene, m-dihalobenzene,
p-dihalobenzene, dihalotoluene, dihalonaphthalene,
methoxy-dihalobenzene, dihalobiphenyl, dihalobenzoic acid,
dihalodiphenyl ether, dihalodiphenyl sulfone, dihalodiphenyl
sulfoxide and dihalodiphenyl ketone. These dihalo aromatic
compounds may be used singly, or in combination of two or more
kinds thereof.
[0050] Here, the halogen atom means each atom of fluorine,
chlorine, bromine and iodine and is preferably a chlorine atom. Two
halogen atoms in the dihalo aromatic compound may be the same or
different from each other. As the dihalo aromatic compound,
o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene or a
mixture of two or more kinds thereof is used in many cases.
4. Disulfide Compound
[0051] In the present invention, the polymerization reaction in the
polymerization step is performed in the presence of a disulfide
compound. The disulfide compound is added during the time interval
between a stage when the conversion ratio of the dihalo aromatic
compound is 0% and a stage when the polyhalo aromatic compound is
added, namely, during the time interval between a stage when the
conversion ratio of the dihalo aromatic compound after the start of
polymerization is 0% and a stage before the polyhalo aromatic
compound is added.
[0052] Examples of the disulfide compound include diphenyl
disulfide (DPDS), p-p'ditolyldisulfide, dibenzyldisulfide,
dibenzoyldisulfide and dithiobenzoyldisulfide. Among them, diphenyl
disulfide is preferred.
[0053] The disulfide compound has an --S--S-- portion, and thus an
--S-- substituent group formed by the cleavage of the disulfide
compound is assumed to be substituted for halogen groups (chlorine
groups) at some terminals of the PAS in the middle of the
polymerization. For example, when the disulfide compound is
diphenyl disulfide, the branched PAS resin obtained by separating
and recovering after the polymerization reaction contains
--S--C.sub.6H.sub.5 which has reacted with the terminals.
[0054] That is, when the disulfide compound is diphenyl disulfide
and the dihalo aromatic compound is dihalobenzene, most of the
terminal group components of the branched PAS resin of the present
invention are formed from --Cl, --S--C.sub.6H.sub.5 which is a
reacted disulfide compound, --SH, and nitrogen compounds derived
from the organic amide solvent. An analysis of these terminal end
components can be performed quantitatively or qualitatively by
elemental analysis, high-temperature NMR analysis, or IR analysis.
In addition, as a specific example of these assay methods, it is
possible to calculate the amount of --S--C.sub.6H.sub.5, which is a
reacted disulfide compound, by assaying --Cl by elemental analysis,
assaying --SH by a titration, a derivative reaction, or an IR
method, or analyzing the nitrogen of nitrogen compounds derived
from the organic amide solvent.
5. Polyhalo Aromatic Compound
[0055] In the present invention, a polyhalo aromatic compound
having three or more halogen substituent groups in the molecule is
used to introduce a branched structure into the PAS resin. The
halogen substituent group is typically a halogen atom directly
bonded to the aromatic ring. The halogen atom means each atom of
fluorine, chlorine, bromine and iodine and is preferably a chlorine
atom. A plurality of halogen atoms in the polyhalo aromatic
compound may be the same or different from each other.
[0056] Examples of the polyhalo aromatic compound include
1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene,
1,3,5-trichlorobenzene, hexachlorobenzene,
1,2,3,4-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene,
1,3,5-trichloro-2,4,6-trimethylbenzene, 2,4,6-trichlorotoluene,
1,2,3-trichloronaphthalene, 1,2,4-trichloronaphthalene,
1,2,3,4-tetrachloronaphthalene, 2,2',4,4'-tetrachlorobiphenyl,
2,2', 4,4'-tetrachlorobenzophenone and
2,4,2'-trichlorobenzophenone.
[0057] These polyhalo aromatic compounds may be used singly, or in
combination of two or more kinds thereof. Among the polyhalo
aromatic compounds, trihalobenzene such as 1,2,4-trichlorobenzene
or 1,3,5-trichlorobenzene is preferred, and trichlorobenzene is
more preferred.
[0058] In order to introduce a branched structure, for example, an
active hydrogen-containing halogenated aromatic compound or a
halogenated aromatic nitro compound may be used in a small
amount.
6. Molecular Weight Modifier
[0059] In order to form a terminal of a specific structure in a PAS
formed or regulate a polymerization reaction or a molecular weight,
a monohalo compound may be used in combination. Not only a monohalo
aromatic compound but also a monohalo aliphatic compound may be
used. Examples of the monohalo compound include
monohalo-substituted saturated or unsaturated aliphatic
hydrocarbons such as monohalopropane, monohalobutane,
monohaloheptane, monohalohexane, aryl halide and chloroprene;
monohalo-substituted saturated cyclic hydrocarbons such as
monohalocyclohexane and monohalodecalin; monohalo-substituted
aromatic hydrocarbons such as monohalobenzene, monohalonaphthalene,
4-chlorobenzoic acid, methyl 4-chlorobenzoate, 4-chlorodiphenyl
sulfone, 4-chlorobenzonitrile, 4-chlorobenzotrifluoride,
4-chloronitrobenzene, 4-chloroacetophenone, 4-chlorobenzophenone
and benzyl chloride; and the like.
7. Organic Amide Solvent
[0060] In the present invention, an organic amide solvent, which is
an aprotic polar organic solvent, is used as a solvent for the
dehydration reaction and the polymerization reaction. The organic
amide solvent is preferably stable toward alkali at high
temperatures.
[0061] Specific examples of the organic amide solvent include amide
compounds such as N,N-dimethylformamide and N,N-dimethylacetamide;
N-alkyl caprolactam compounds such as
N-methyl-.epsilon.-caprolactam; N-alkyl pyrrolidone compounds or
N-cycloalkyl pyrrolidone compounds such as N-methyl-2-pyrrolidone
and N-cyclohexyl-2-pyrrolidone; N,N-dialkyl imidazolidinone
compounds such as 1,3-dialkyl-2-imidazolidinone; tetraalkyl urea
compounds such as tetramethyl urea; and hexaalkyl phosphoric acid
triamide compounds such as hexamethyl phosphoric acid triamide; and
the like. These organic amide solvents can be used singly, or in
combination of two or more kinds thereof.
[0062] Among these organic amide solvents, N-alkyl pyrrolidone
compounds, N-cycloalkyl pyrrolidone compounds, N-alkyl caprolactam
compounds, and N,N-dialkyl imidazolidinone compounds are preferred,
N-methyl-2-pyrrolidone (NMP), N-methyl-.epsilon.-caprolactam, and
1,3-dialkyl-2-imidazolidinone are more preferred, and NMP is
particularly preferred.
8. Polymerization Assisting Agent
[0063] In the present invention, as necessary, various
polymerization assisting agents can be used to facilitate the
polymerization reaction. Specific example of the polymerization
assisting agents include organic sulfonic acid metal salts, which
are generally known as a polymerization assisting agent of PAS
resin, lithium halide, organic carboxylic acid metal salts and
phosphoric acid alkali metal salts.
9. Phase Separation Agent
[0064] In the present invention, various phase separation agents
can be used to induce a liquid-liquid phase separation state so as
to obtain a PAS with an adjusted melt viscosity in a short amount
of time with a low halogen content. A phase separation agent is a
compound having an action of dissolving in an organic amide solvent
so as to reduce the solubility of the PAS in the organic amide
solvent by itself or in the presence of a small amount of water.
The phase separation agent itself is a compound that is not a
solvent of the PAS.
[0065] A compound that is publicly known as a phase separation
agent of PAS can be typically used as the phase separation agent.
Also, a compound to be used as a polymerization assisting agent is
included in the phase separation agent. Here, the phase separation
agent means a compound that is used at a quantitative ratio to
serve as the phase separation agent in the phase separation
polymerization reaction. Specific examples of the phase separation
agent include water, organic carboxylic acid metal salts, organic
sulfonic acid metal salts, alkali metal halides such as lithium
halide, alkaline earth metal halides, alkaline earth metal salts of
aromatic carboxylic acids, phosphoric acid alkali metal salts,
alcohols and paraffin hydrocarbons, and the like. The organic
carboxylic acid metal salts are preferably alkali metal carboxylic
salts such as lithium acetate, sodium acetate, potassium acetate,
sodium propionate, lithium valerate, lithium benzoate, sodium
benzoate, sodium phenylacetate and potassium p-toluylate. These
phase separation agents may be used singly, or in combination of
two or more kinds thereof. Among these phase separation agents,
water (which is inexpensive and in which the posttreatment step is
easy) or a combination of water with organic carboxylic acid metal
salts such as alkali metal carboxylic salts is particularly
preferred.
10. Method for Manufacturing Branched PAS Resin Including an --S--
Substituent Group with a Cleaved Disulfide Compound
[0066] The method for manufacturing a branched PAS resin of the
present invention is a method for manufacturing a branched PAS
resin having main characteristics in that the ratio of the dihalo
aromatic compound to the sulfur source is controlled so as to be
decreased and some terminals of a PAS in the middle of the
polymerization are modified by a reaction of the PAS in the middle
of the polymerization with a disulfide compound before introduction
of a branched structure in the polymerization step and then the
branched structure is introduced.
[0067] More specifically, the manufacturing method of the present
invention is a method for manufacturing a branched polyarylene
sulfide resin including an --S-- substituent group with a cleaved
disulfide compound that polymerizes a sulfur source with a dihalo
aromatic compound in an organic amide solvent in the presence of a
disulfide compound and a polyhalo aromatic compound having three or
more halogen substituent groups in the molecule, the method
including the steps of: performing a polymerization reaction of a
sulfur source with a dihalo aromatic compound in an organic amide
solvent using the dihalo aromatic compound in an amount of from
0.95 to 1.02 mol per mol of sulfur source; adding a disulfide
compound in an amount of from 0.001 to 0.03 mol per mol of sulfur
source during the time interval between a stage when the conversion
ratio of the dihalo aromatic compound is 0% and a stage when a
polyhalo aromatic compound is added and reacting the mixture;
adding a polyhalo aromatic compound (in an amount of from 0.002 to
0.06 mol per mol of sulfur source and an amount of from 0.2 to 12
mol per mol of disulfide compound) to the polymerization reaction
mixture at a stage when the conversion ratio of the dihalo aromatic
compound reaches 80% or greater; and performing a phase separation
polymerization reaction in the presence of a phase separation
agent.
[0068] The manufacturing method of the present invention includes
essential steps of: (i) performing a polymerization reaction of a
sulfur source with a dihalo aromatic compound in an organic amide
solvent using the dihalo aromatic compound in an amount of from
0.95 to 1.02 mol per mol of sulfur source; (ii) adding a disulfide
compound in an amount of from 0.001 to 0.03 mol per mol of sulfur
source during the time interval between a stage when the conversion
ratio of the dihalo aromatic compound is 0% and a stage when a
polyhalo aromatic compound is added and reacting the mixture; and
(iii) adding a polyhalo aromatic compound (in an amount of from
0.002 to 0.06 mol per mol of sulfur source and an amount of from
0.2 to 12 mol per mol of disulfide compound) to the polymerization
reaction mixture at a stage when the conversion ratio of the dihalo
aromatic compound reaches 80% or greater and performing a phase
separation polymerization reaction in the presence of a phase
separation agent.
[0069] Particularly, the manufacturing conditions in the steps (i)
to (iii) allow for the production of a branched PAS resin having a
highly balanced and appropriate range of the halogen (chlorine)
content, the melt viscosity and the branched structure (melt
viscoelasticity tan .delta. as an indicator) as described above.
Therefore, these manufacturing requirements are restrictions that
constitute the basis of the manufacturing method of the present
invention.
[0070] Specifically, it is preferable to accurately adjust the
content ratio of each of the components by inserting a dehydration
step and a charging step before the polymerization step to perform
a polymerization reaction. It is preferable to use a sulfur source
containing an alkali metal hydrosulfide as the sulfur source. The
sulfur source and the alkali metal hydroxide are preferable in that
they are both present in the polymerization reaction system.
[0071] Consequently, the preferred manufacturing method of the
present invention is a method for manufacturing a branched PAS
resin including an --S-- substituent group with a cleaved disulfide
compound, including: the steps of: (1) heating a mixture containing
an organic amide solvent, a sulfur source including an alkali metal
hydrosulfide and an alkali metal hydroxide, and discharging at
least part of the distillate containing water from the inside of
the system containing the mixture to the outside of the system
(dehydration step 1); (2) mixing the mixture remaining inside the
system in the dehydration step 1 with a dihalo aromatic compound to
prepare a charged mixture containing an organic amide solvent, a
sulfur source (hereinafter, referred to as "charged sulfur
source"), an alkali metal hydroxide, water and a dihalo aromatic
compound, wherein the amount of the dihalo aromatic compound in the
charged mixture is from 0.95 to 1.02 mol per mol of charged sulfur
source (charging step 2); (3) heating the charged mixture to a
temperature of from 170 to 270.degree. C. and performing a
polymerization reaction of the charged sulfur source and the dihalo
aromatic compound in a water-containing organic amide solvent;
adding a disulfide compound in an amount of from 0.001 to 0.03 mol
per mol of charged sulfur source during the time interval between a
stage when the conversion ratio of the dihalo aromatic compound is
0% and a stage when a polyhalo aromatic compound is added and
reacting the mixture; adding a polyhalo aromatic compound (in an
amount of from 0.002 to 0.06 mol per mol of charged sulfur source
and an amount of from 0.2 to 12 mol per mol of disulfide compound)
to the polymerization reaction mixture at a stage when the
conversion ratio of the dihalo aromatic compound reaches 80% or
greater and performing a polymerization reaction (prestage
polymerization step 3); and (4) heating the polymerization reaction
mixture to a temperature of 240.degree. C. or higher and performing
a phase separation polymerization reaction at a temperature of from
240 to 290.degree. C. in the presence of a phase separation agent
(poststage polymerization step 4). It is clear that the
conventional method of using a sulfur source containing an alkali
metal hydrosulfide and reacting the sulfur source with a dihalo
aromatic compound and a polyhalo aromatic compound in the presence
of the alkali metal hydroxide is suitable as a method for
manufacturing a branched PAS resin having an excellent balance in
various characteristics.
[0072] According to the research results by the present inventors,
the main difference between the method for manufacturing a branched
PAS resin of the present invention and the conventional method of
manufacturing a branched PAS resin is that (i) the ratio of the
dihalo aromatic compound to the sulfur source is strictly
controlled so as to be decreased, and (ii) the terminals of a PAS
are modified by a reaction of the PAS in the middle of the
polymerization with a disulfide compound before introduction of a
branched structure in the polymerization step and then the branched
structure is introduced.
[0073] The newly discovered manufacturing conditions indicate that
it is possible to reduce the halogen (chlorine) content, and it is
possible realize a wider range of numerical value of melt viscosity
or melt viscoelasticity tan .delta., and it is possible to obtain a
branched PAS resin including an --S-- substituent group with a
cleaved disulfide compound which is preferred as a polymer
modifier.
[0074] In order to stably perform this polymerization reaction, it
is preferable to adjust the content ratio of each of the components
to be subjected to a polymerization reaction, to accurately adjust,
particularly the ratio of halogen to the sulfur source in the
polymerization reaction field, and to strictly control the
polymerization conditions such as the stage of substitution of the
disulfide compound for the terminals of the PAS, the stage of start
of the chain branching reaction with the polyhalo aromatic
compound, the ratio of the polyhalo aromatic compound to the
disulfide compound and the timing for inducing a liquid-liquid
phase separation state. Hereinafter, the preferred manufacturing
method of the present invention will be described more in
detail.
10.1. Dehydration Step 1
[0075] The sulfur source contains water such as hydrated water
(crystallization water) in many cases. When the sulfur source and
alkali metal hydroxide are used as aqueous mixtures, they contain
water as media. The polymerization reaction of the sulfur source
and the dihalo aromatic compound is affected by the water content
in the polymerization reaction system. Generally, a dehydration
step is inserted before the polymerization step so as to adjust the
water content in the polymerization reaction system.
[0076] In the preferred manufacturing method of the present
invention, the dehydration step 1 (hereafter abbreviated as
"dehydration step") includes heating a mixture containing an
organic amide solvent, a sulfur source including an alkali metal
hydrosulfide and an alkali metal hydroxide, and discharging at
least part of the distillate containing water from the inside of
the system containing the mixture to the outside of the system. An
organic amide solvent is used as the medium used in the dehydration
step. The organic amide solvent used in the dehydration step is
preferably the same as the organic amide solvent used in the
polymerization step. From the viewpoint of being industrially
easily available, NMP is more preferred. The amount of the organic
amide solvent is typically from 0.1 to 10 kg, and preferably from
0.15 to 5 kg per mol of sulfur source to be charged in the reaction
vessel.
[0077] The dehydration operation is performed by heating the
mixture formed by adding the raw materials to the reaction vessel
typically at a temperature of 300.degree. C. or less and preferably
within the temperature range of 100 to 250.degree. C., typically
for 15 minutes to 24 hours and preferably for 30 minutes to 10
hours. In the dehydration step, the water and organic amide solvent
are vaporized by heating and distilled. Thus, the water and organic
amide solvent are included in the distillate. Part of the
distillate may be returned to the system to prevent the distillate
from being discharged outside of the system of the organic amide
solvent. In order to adjust the water content, at least part of the
distillate containing water is discharged to the outside of the
system. When the distillate is discharged to the outside of the
system, a very small amount of organic amide solvent is discharged
together with water to the outside of the system.
[0078] In the dehydration step, the hydrogen sulfide from the
sulfur source is vaporized. The vaporized hydrogen sulfide is
discharged to the outside of the system when at least part of the
distillate containing water is discharged to the outside of the
system.
[0079] In the dehydration step, the water content including
hydrated water or an aqueous medium, byproduct water, or the like
is dehydrated until the water content is in a range of the amount
required. In the dehydration step, it is preferable to perform the
dehydration step until the water content is typically from 0.01 to
2 mol, preferably from 0.5 to 1.7 mol, more preferably from 0.8 to
1.65 mol, and even more preferably from 0.9 to 1.6 mol per mol of
effective sulfur source, which is the sulfur source present in the
polymerization reaction system after the dehydration step. When the
water content is excessively decreased in the dehydration step, the
water content can be adjusted to a desired water content by adding
water in the charging step.
[0080] In the dehydration step, it is preferable to heat a mixture
containing an organic amide solvent, a sulfur source including an
alkali metal hydrosulfide and an alkali metal hydroxide (in an
amount of 0.9 to 1.1 mol, preferably from 0.91 to 1.08 mol, more
preferably from 0.92 to 1.07 mol, and even more preferably from
0.93 to 1.06 mol per mol of sulfur source) and discharge at least
part of the distillate containing water from the inside of the
system containing the mixture to the outside of the system.
[0081] The hydrogen sulfide is discharged as gas to the outside of
the system.
10.2. Charging Step 2:
[0082] The charging step 2 (hereafter, sometimes simply abbreviated
as "charging step") is a charging step including mixing the mixture
remaining inside the system in the dehydration step with a dihalo
aromatic compound to prepare a charged mixture containing an
organic amide solvent, a sulfur source (charged sulfur source), an
alkali metal hydroxide, water and a dihalo aromatic compound,
wherein the amount of the dihalo aromatic compound in the charged
mixture is from 0.95 to 1.02 mol per mol of charged sulfur source.
Generally, the content and quantitative ratio of each of the
components are varied in the dehydration step. Accordingly, the
amount of each of the components amount in the charging step needs
to be adjusted taking into consideration the amount of each of the
components in the mixture obtained in the dehydration step.
[0083] In the manufacturing method of the present invention, it is
preferable to prepare a charged mixture containing the following
components: 0.95 to 1.09 mol of an alkali metal hydroxide, 0.01 to
2 mol of water and 0.95 to 1.02 mol of a dihalo aromatic compound
per mol of charged sulfur source in the charging step.
[0084] In the present invention, the amount of the "charged sulfur
source" (effective sulfur source), which is the sulfur source
present in the polymerization reaction system after the dehydration
step, can be calculated by subtracting the "molar amount of the
hydrogen sulfide vaporized in the dehydration step" from the "molar
amount of the sulfur source charged in the dehydration step".
[0085] The quantitative ratio (molar ratio) of each of the
components in the charged mixture is adjusted by typically adding a
necessary component to the mixture obtained in the dehydration
step. The dihalo aromatic compound is added to the mixture in the
charging step. When the amount of alkali metal hydroxide or water
in the mixture obtained in the dehydration step is too small, these
components are added in the charging step. When the distillation
amount of the organic amide solvent in the dehydration step is too
large, the organic amide solvent is added in the charging step. In
order to adjust the charged sulfur source, a sulfur source may be
added in the charging step. Thus, in the charging step, a sulfur
source, an organic amide solvent, water and an alkali metal
hydroxide may be added as necessary in addition to the dihalo
aromatic compound.
[0086] When the molar ratio of the alkali metal hydroxide per mol
of charged sulfur sources is too large, the deterioration of the
organic amide solvent may be increased or an abnormal reaction
during polymerization may be caused. Further, this tends to cause a
decrease in yield or quality of the branched PAS resin being
formed. When the sulfur source containing an alkali metal
hydrosulfide is used as the sulfur source, the molar amount of the
alkali metal hydroxide per mol of charged sulfur source is from
0.95 to 1.09 mol, preferably from 0.98 to 1.085 mol, more
preferably from 0.99 to 1.083 mol, and even more preferably from
1.0 to 1.08 mol. In this case, the amount of the alkali metal
hydroxide is the total amount of the alkali metal hydroxide charged
in the dehydration step 1, the alkali metal hydroxide formed with
the generation of the hydrogen sulfide vaporized in the dehydration
step 1 and the alkali metal hydroxide to be added in the charging
step 2.
[0087] In the prestage polymerization step 3 described below, the
molar ratio of the alkali metal hydroxide per mol of charged sulfur
source is within the above range so that the polymerization
reaction is stably carried out and a high-quality branched PAS
resin is easily obtained.
[0088] In the charging step, it is preferable to adjust the molar
amount so that the molar amount of water per mol of charged sulfur
source is from 0.01 to 2 mol, preferably from 0.6 to 1.8 mol, more
preferably from 0.9 to 1.7 mol, and even more preferably from 1.0
to 1.65 mol. In this case, the amount of water is determined by
taking into consideration the water formed with the generation of
the alkali metal sulfide in the dehydration step 1 and the water
consumed with the vaporization of the hydrogen sulfide in the
dehydration step 1. When the amount of coexisting water is too
small in the prestage polymerization step 3, undesirable reactions
such as decomposition reactions of the formed polymer is likely to
occur. When the amount of coexisting water is too large, the
polymerization reaction rate becomes significantly slow, or
decomposition reactions occur.
[0089] In the charging step, it is preferable to prepare a charged
mixture containing a dihalo aromatic compound in an amount of from
0.95 to 1.02 mol, preferably from 0.96 to 1.01 mol, more preferably
from 0.97 to 1.0 mol, and even more preferably from 0.98 to 0.999
mol per mol of charged sulfur source, and more preferably in an
amount of from 0.985 to 0.998 mol, and even more preferably from
0.986 to 0.997 mol depending on the branched PAS resin. When the
ratio of the dihalo aromatic compound is outside the above range,
it becomes difficult to control the melt viscosity within a desired
range, it becomes difficult to decrease the halogen content within
a target range, or the melt viscoelasticity tan .delta. is outside
a suitable range. Further, the reaction of the PAS in the middle of
the polymerization with the disulfide compound and/or the polyhalo
aromatic compound may not be stable.
[0090] As described above, one of the characteristics of the
present invention is that the ratio of the dihalo aromatic compound
to the sulfur source is controlled so as to be decreased.
[0091] In the charging step, the amount of the organic amide
solvent is typically from 0.1 to 10 kg, preferably from 0.13 to 5
kg, more preferably from 0.15 to 2 kg per mol of charged sulfur
source.
10.3. Prestage Polymerization Step 3:
[0092] The prestage polymerization step 3 in the preferred
manufacturing method of the present invention (hereinafter, simply
abbreviated as "prestage polymerization step") includes heating a
charged mixture to a temperature of from 170 to 270.degree. C. and
performing a polymerization reaction of a charged sulfur source and
a dihalo aromatic compound in a water-containing organic amide
solvent; adding a disulfide compound in an amount of from 0.001 to
0.03 mol per mol of charged sulfur source during the time interval
between a stage when the conversion ratio of the dihalo aromatic
compound is 0% and a stage when a polyhalo aromatic compound is
added, and reacting the mixture; and adding the polyhalo aromatic
compound to the polymerization reaction mixture in an amount of
0.002 to 0.06 mol per mol of charged sulfur source and an amount of
0.2 to 12 mol per mol of disulfide compound at a stage when the
conversion ratio of the dihalo aromatic compound reaches 80% or
greater.
[0093] As described above, one of the characteristics of the
present invention is that the disulfide compound is added in an
amount of from 0.001 to 0.03 mol per mol of charged sulfur source
during the time interval between a stage when the conversion ratio
of the dihalo aromatic compound at the start of the polymerization
is 0% and a stage when the polyhalo aromatic compound is added.
[0094] The disulfide compound is added in an amount of from 0.001
to 0.03 mol, preferably from 0.0015 to 0.02 mol, and more
preferably from 0.002 to 0.015 mol per mol of charged sulfur
source. When the amount of the disulfide compound is too small, the
amount of substitution of the cleaved disulfide compound for the
terminals of the PAS in the middle of the polymerization is
insufficient. Thus, the melt viscosity of the branched PAS resin to
be obtained is not low and it becomes difficult to reduce the
halogen content. When the amount of the disulfide compound is too
large, the melt viscosity is excessively decreased, whereby the
processability is deteriorated and it becomes difficult to suppress
generation of burrs.
[0095] The addition stage of the disulfide compound may be any
stage as long as it is during the time interval between a stage
when the conversion ratio of the dihalo aromatic compound is 10%
and a stage when the polyhalo aromatic compound is added. It is
preferably during the time interval between a stage when the
conversion ratio of the dihalo aromatic compound is 0% and a stage
when the polyhalo aromatic compound is added, more preferably
during the time interval between a stage when the conversion ratio
of the dihalo aromatic compound is 30% and a stage when the
polyhalo aromatic compound is added, even more preferably during
the time interval between a stage when the conversion ratio of the
dihalo aromatic compound is 50% and a stage when the polyhalo
aromatic compound is added, and yet even more preferably during the
time interval between a stage when the conversion ratio of the
dihalo aromatic compound is 70% and a stage when the polyhalo
aromatic compound is added.
[0096] Based on various characteristics such as target melt
viscosity of the branched PAS resin, halogen content, melt
viscoelasticity tan .delta., thermal stability and processability,
it is important to adjust the amount of the disulfide compound to
be added and the addition stage.
[0097] In the polymerization reaction field, the reaction time
required for the added disulfide compound is about from 10 minutes
to 5 hours, preferably from 15 minutes to 4 hours, more preferably
from 18 minutes to 3 hours, and even more preferably from 20
minutes to 2 hours.
[0098] The conversion ratio of the dihalo aromatic compound is from
75 to 99%, preferably from 80 to 98.5%, more preferably from 83 to
98%, and even more preferably from 85 to 97.5%.
[0099] The conversion ratio of the dihalo aromatic compound is
important to control the molecular weight of a polymer used as a
group for obtaining the target melt viscosity. At a stage when the
conversion ratio of the dihalo aromatic compound is 75% or greater,
the weight average molecular weight of the produced polymer
(prepolymer) included in the polymerization reaction mixture is
typically 6,000 or greater.
[0100] The amount of the dihalo aromatic compound remaining in the
reaction mixture is determined by gas chromatography, and the
conversion ratio of the dihalo aromatic compound can be calculated
based on this remaining amount, the charged amount of the dihalo
aromatic compound, and the charged amount of the sulfur source.
When the dihalo aromatic compound (abbreviated as "DHA") is added
in a greater molar amount than the sulfur source, the conversion
ratio is calculated using the following formula 1:
Conversion ratio=[DHA charged amount (mol)-DHA remaining amount
(mol)]/[DHA charged amount (mol)-DHA excess amount (mol)] (1)
[0101] In other cases, the conversion ratio is calculated using the
following formula 2:
Conversion ratio=[DHA charged amount (mol)-DHA remaining amount
(mol)]/[DHA charged amount (mol)] (2)
[0102] In the manufacturing method of the present invention, a
polymerization reaction is performed by adding the polyhalo
aromatic compound (in an amount of from 0.002 to 0.06 mol per mol
of charged sulfur source and an amount of from 0.2 to 12 mol per
mol of disulfide compound) to the polymerization reaction mixture,
at a stage when the conversion ratio of the dihalo aromatic
compound is 80% or greater.
[0103] Preferably, the addition stage of the polyhalo aromatic
compound is a stage when the conversion ratio of the dihalo
aromatic compound is 80% or greater. More preferably, the addition
stage is a stage when the conversion ratio of the dihalo aromatic
compound is from 80 to 99%, preferably from 83 to 99%, and more
preferably from 85 to 98%.
[0104] The amount of the polyhalo aromatic compound to be added is
from 0.002 to 0.06 mol, preferably from 0.008 to 0.05 mol, and more
preferably from 0.011 to 0.04 mol per mol of charged sulfur
source.
[0105] When the amount of the polyhalo aromatic compound to be
added is small, the formation of a branched structure becomes
insufficient. Even if the obtained PAS is used as a polymer
modifier, characteristics serving as a burr suppressor may not be
sufficient. On the other hand, when the amount of the polyhalo
aromatic compound to be added is large, the melt viscosity is
increased and the melt viscoelasticity tan .delta. may be outside
the target range.
[0106] In the manufacturing method of the present invention, the
melt viscosity and melt viscoelasticity tan .delta. are within an
appropriate range and further a branched PAS resin having a low
halogen content is obtained. To achieve this, as described above,
it is important to adjust the amount of the polyhalo aromatic
compound to be added within the range of from 0.002 to 0.06 mol per
mol of charged sulfur source and the range of from 0.2 to 12 mol
per mol of disulfide compound as described above.
[0107] Hence, it is necessary to adjust the amount of the polyhalo
aromatic compound to be added within the range of from 0.2 to 12
mol, preferably from 0.5 to 11.5 mol, more preferably from 1 to 11
mol, even more preferably from 1.5 to 10.5 mol, and yet even more
preferably from 2 to 10 mol per mol of disulfide compound.
[0108] The ratio of the amount of the polyhalo aromatic compound to
the disulfide compound is deemed to be an important indicator to
determine a balance between the substitution level of the cleavage
of the disulfide compound for the terminals of the PAS polymer and
the branched degree of the polyhalo aromatic compound. When this
ratio is within the above range, the branched PAS resin of the
present invention having an appropriate melt viscosity and melt
viscoelasticity tan .delta. can be obtained.
[0109] When the ratio is less than 0.2 mol, it becomes difficult to
generate branched structures and thus it becomes difficult to
introduce a target branched structure.
[0110] When the ratio is greater than 12 mol, the melt viscosity is
excessively increased. The melt viscoelasticity tan .delta. may be
decreased.
[0111] In the polymerization reaction field, the reaction time
required for the added polyhalo aromatic compound is about from 5
minutes to 3 hours, preferably from 7 minutes to 2.5 hours, more
preferably from 8 minutes to 2.25 hours, and even more preferably
from 10 minutes to 2 hours.
[0112] When the polyhalo aromatic compound is added at a stage when
the conversion ratio of the dihalo aromatic compound is less than
80%, the melt viscosity of the branched PAS resin to be obtained
tends to be high, whereas the melt viscoelasticity tan .delta. is
excessively decreased and the burr suppressing effect becomes
insufficient.
[0113] The important thing is that when the polyhalo aromatic
compound is added, the amount of the polyhalo aromatic compound to
be added is adjusted so that the total of the halogen content in
the dihalo aromatic compound and the halogen content in the
polyhalo aromatic compound is from 1.01 to 1.05 mol, preferably
from 1.011 to 1.045 mol, more preferably from 1.012 to 1.043 mol,
and even more preferably from 1.015 to 1.04 mol per mol of charged
sulfur source, in the polymerization reaction field.
[0114] In this case, for example, when 1,2,4-trichlorobenzene (TCB)
is used as the polyhalo aromatic compound, the total amount of 1.5
fold of the molar amount of the polyhalo aromatic compound and the
molar amount, for example, when p-dichlorobenzene (pDCB) is used as
the dihalo aromatic compound is the total amount of the amount of
halogen (chlorine). In other words, it is a value obtained by
dividing the total amount of 2 fold of pDCB/S and 3 fold of TCB/S
by 2.
[0115] When the amount of the polyhalo aromatic compound is too
large, the melt viscosity of the branched PAS resin is increased
and the melt viscoelasticity tan .delta. is excessively decreased,
whereby the burr suppressing effect is reduced and further the
processability is deteriorated. When the amount of the polyhalo
aromatic compound is too small, the introduction of the branched
structure becomes insufficient and the burr suppressing effect is
impaired.
[0116] In the poststage polymerization step 4 described below, the
main purpose is to perform the phase separation polymerization
reaction in the liquid-liquid phase separation state in the
presence of the phase separation agent. Thus, the phase separation
agent may be added in the prestage polymerization step 3.
[0117] Generally, a liquid-liquid phase separation state can be
formed by increasing the temperature of the polymerization system
in the presence of the phase separation agent. The time of adding
the phase separation agent varies depending on the kind and amount
of the phase separation agent. For example, when the phase
separation agent is water, the phase separation agent is added at a
stage when the conversion ratio of the dihalo aromatic compound in
the prestage polymerization step reaches 80% or greater. Organic
carboxylic acid salts, alkali metal halides or the like may be
added before or in early stages of polymerization. In this case,
the reaction system is converted to a phase separation state by
increasing the temperature during the poststage polymerization.
[0118] The phase separation agent may be added simultaneously with
the polyhalo aromatic compound or may be added after addition of
the polyhalo aromatic compound. For example, the polyhalo aromatic
compound is added to the polymerization reaction mixture at a stage
when the conversion ratio of the dihalo aromatic compound reaches
80% or greater. Thereafter, the phase separation agent can be added
at a stage when the conversion ratio of the dihalo aromatic
compound is 99% or less and preferably 98% or less.
[0119] As the phase separation agent, the above-described alkali
metal carboxylic salts or water can be used, and preferably water
is used. It is preferable to use water because the cost is low and
it is easy to perform the posttreatment.
[0120] When the phase separation agent is water, it is preferable
to add water to the polymerization reaction mixture so that the
water content in the polymerization reaction mixture (total water
content) is greater than 2 mol and less than or equal to 10 mol,
preferably from 2.3 to 7 mol, and more preferably from 2.5 to 5 mol
per mol of charged sulfur source.
[0121] When water and another phase separation agent other than
water is used as the phase separation agent, it is preferable that
the water content (total amount) in the polymerization reaction
mixture is from 0.01 to 7 mol, preferably from 0.1 to 6 mol, and
more preferably from 1 to 4 mol per mol of charged sulfur source
and the existing amount of another phase separation agent other
than water is from 0.01 to 3 mol, preferably from 0.02 to 2 mol,
and more preferably from 0.03 to 1 mol. In this case, another phase
separation agent other than water may be added at any stage from
before the polymerization to the prestage polymerization.
[0122] In the poststage polymerization step 4 described below, the
temperature is increased in the presence of the phase separation
agent, whereby the polymerization reaction is typically continued
in a state in which a phase separation to a polymer dense phase and
a polymer dilute phase takes place. When the amount of the phase
separation agent to be added is too small or the temperature is too
low, it becomes difficult to perform the phase separation
polymerization or it becomes difficult to obtain a branched PAS
resin having desired characteristics. When the existing amount of
the phase separation agent is too large, it takes a long time for
the polymerization reaction to be completed or it becomes difficult
to form a granular polymer.
[0123] The polymerization reaction time in the prestage
polymerization step (in total with the polymerization time in the
poststage polymerization step 4 described below) is typically in a
range of from 10 minutes to 72 hours, preferably in a range of from
0.5 to 48 hours, more preferably in a range of from 0.5 to 15
hours, and even more preferably in a range of from 1 to 12
hours.
[0124] In the prestage polymerization step, the polymerization
reaction is started by heating the charged mixture to preferably a
temperature of from 170 to 270.degree. C., more preferably a
temperature of from 180 to 240.degree. C., and even more preferably
a temperature of from 190 to 235.degree. C.
10.4. Poststage Polymerization Step 4:
[0125] The poststage polymerization step 4 (hereinafter may be
abbreviated as "poststage polymerization step") is described
below.
[0126] The poststage polymerization step is a step that includes
heating a polymerization reaction mixture, increasing the
temperature to a temperature of 240.degree. C. or higher, and
performing the phase separation polymerization reaction in the
presence of the phase separation agent at a temperature of from 240
to 290.degree. C., and is a very important step to manage the
growth of polymer in the polymer dense phase and the development of
the branched structure of polymer in the polymer dense phase.
[0127] In the poststage polymerization step of the manufacturing
method of the present invention, the phase separation
polymerization reaction is continued in a state in which the
reaction mixture is phase separated into a polymer dense phase and
a polymer dilute phase. Generally, the phase separation
polymerization reaction is performed while stirring. Thus, the
phase separation polymerization reaction is actually performed in a
state in which the polymer dense phase is dispersed as droplets in
an organic amide solvent (polymer dilute phase).
[0128] Hence, in the poststage polymerization step, the polymer
dilute phase and the polymer dense phase are present in a
liquid-liquid phase separation state, the onset and growth of chain
branching reaction of the polyhalo aromatic compound with the PAS
polymer proceeds mainly in the polymer dense phase, the bonding of
the PAS polymers during the growth reaction efficiently increases
the molecular weight, and thus a branched structure is formed.
[0129] In the manufacturing method of the present invention, the
poststage polymerization step is an important step to obtain a
branched PAS resin having a target melt viscosity value, low
halogen content and characteristics in the melt viscoelasticity tan
.delta..
[0130] In the poststage polymerization step, the polymerization
reaction is continued at a temperature of from 240 to 290.degree.
C. and preferably a temperature of from 245 to 270.degree. C.
Although the polymerization temperature can be maintained at a
constant temperature, it may be gradually increased or decreased as
needed.
[0131] The polymerization reaction time (in total with the
polymerization time in the prestage polymerization step) is
typically in a range of from 10 minutes to 72 hours and preferably
in a range of from 30 minutes to 48 hours. The polymerization time
in the poststage polymerization step is in a range of from 2 to 10
hours in many cases.
11. Posttreatment Step
[0132] The posttreatment after the polymerization reaction can be
carried out in accordance with an ordinary manner. For example,
when the polymerization reaction mixture is cooled after the
completion of polymerization reaction, a slurry containing a
produced polymer is obtained. The branched PAS resin can be
recovered by filtering the cooled slurry directly or after dilution
with water, repeating the washing and filtering cycle, and finally
drying the resulting product.
[0133] According to the manufacturing method of the present
invention, it is possible to form a granular polymer. Thus, the
granular polymer can be separated from the slurry by sieving using
a screen. In the separation step, byproducts having a very high
halogen content or oligomers can be easily separated. As a result,
a PAS having a low halogen content is obtained, which is
preferable. The granular polymer may be directly screened from the
slurry at a high temperature.
[0134] Sieving is typically performed using a 100 mesh screen (with
a sieve opening of 150 .mu.m). In the case of sieving with a 100
mesh screen (with a sieve opening of 150 .mu.m), the yield is
typically 70% or greater and preferably 75% or greater.
[0135] After the sieving, the polymer is preferably washed with the
same organic amide solvent as the polymerization solvent, ketone
(e.g., acetone) or an organic solvent such as alcohols (e.g.,
methanol). The polymer may be washed with high temperature water or
the like. The polymer can be treated with a salt such as acid or
ammonium chloride. When the average particle size of the formed
granular polymer is too large, a grinding step may be inserted to
give a desired average particle size. The granular polymer can also
be ground and/or classified.
12. Branched PAS Resin Including --S-- Substituent Group with
Cleaved Disulfide Compound
[0136] According to the manufacturing method of the present
invention, it is possible to obtain a branched PAS resin including
an --S-- substituent group with a cleaved disulfide compound,
wherein the resin has the following characteristics i to iii:
i) a halogen content of 4,000 ppm or less; ii) a melt viscosity as
measured at a temperature of 330.degree. C. and a shear rate of 2
sec.sup.-1 of 1.0.times.10.sup.4 to 50.0.times.10.sup.4 Pas; and
iii) a melt viscoelasticity tan .delta. as measured at a
temperature of 310.degree. C. and an angular velocity of 1 rad/sec
of 0.1 to 0.6.
[0137] The halogen content of the branched PAS resin including an
--S-- substituent group with a cleaved disulfide compound of the
present invention is preferably 3,000 ppm or less, more preferably
2,000 ppm or less, even more preferably 1,800 ppm or less, and yet
even more preferably 1,700 ppm or less. Depending on the intended
use of the branched PAS resin, the halogen content is preferably
1,600 ppm or less and more preferably 1,500 ppm or less.
[0138] The melt viscosity A of the branched PAS resin including an
--S-- substituent group with a cleaved disulfide compound of the
present invention (as measured at a temperature of 330.degree. C.
and a shear rate of 2 sec.sup.-1) is preferably from
2.0.times.10.sup.4 to 48.0.times.10.sup.4 Pas, more preferably from
2.5.times.10.sup.4 to 47.5.times.10.sup.4 Pas, and even more
preferably from 3.0.times.10.sup.4 to 47.0.times.10.sup.4 Pas. When
the melt viscosity of the branched PAS resin is too high, the burr
suppressing effect becomes insufficient and the surface properties
of the molded product are deteriorated. When the melt viscosity of
the branched PAS resin is too low, the burr suppressing effect
becomes poor.
[0139] Additionally, in the present invention, the melt viscosity B
is measured (at a temperature of 310.degree. C. and a shear rate of
1,200 sec.sup.-1).
[0140] Generally, when the measurement temperature is high, the
melt viscosity to be measured is low, whereas when the shear rate
is high, the melt viscosity to be measured is low.
[0141] The melt viscoelasticity tan .delta. of the branched PAS
resin including an --S-- substituent group with a cleaved disulfide
compound of the present invention (as measured at a temperature of
310.degree. C. and an angular velocity of 1 rad/sec) is preferably
from 0.11 to 0.58, more preferably from 0.12 to 0.57, and even more
preferably from 0.13 to 0.56. The melt viscoelasticity tan .delta.
of the branched PAS resin is within the above range so that an
excellent burr suppressing effect is obtained. When the melt
viscoelasticity tan .delta. of the branched PAS resin is too low or
too high, the burr suppressing effect becomes poor.
[0142] The melt viscoelasticity tan .delta. of an extremely
high-molecular weight linear PAS resin or a conventional PAS resin
with a crosslinked structure typically has a value lower than 0.10
depending on the level of crosslinking. On the other hand, the melt
viscoelasticity tan .delta. of a significantly low-molecular weight
PAS resin typically has a value greater than 0.6.
[0143] The average particle size of the branched PAS resin
including an --S-- substituent group with a cleaved disulfide
compound of the present invention is preferably from 60 to 1,500
.mu.m, more preferably from 100 to 1,300 .mu.m, even more
preferably from 150 to 1,000 .mu.m, and yet even more preferably
from 200 to 950 .mu.m.
[0144] In order to adjust the average particle size of the branched
PAS resin, the branched PAS resin obtained by polymerization may be
ground and/or classified. When the average particle size of the
branched PAS resin is too small, it becomes difficult to handle or
meter. When the average particle size of the branched PAS resin is
too large, the surface properties of the molded product are
impaired and it is difficult to be blended with another resin such
as the linear PAS resin.
[0145] Preferably, the branched PAS resin including an --S--
substituent group with a cleaved disulfide compound of the present
invention is blended with the linear PAS resin as a polymer
modifier and the resultant mixture is used as a burr suppressor.
The linear PAS resin is a PAS resin obtained as a high-molecular
weight polymer during the polymerization. In this regard, however,
the linear PAS resin may include a slightly branched or crosslinked
structure which is a byproduct formed during the
polymerization.
[0146] The linear PAS resin is preferably a linear PPS resin having
a melt viscosity as measured at a temperature of 310.degree. C. and
a shear rate of 1,216 sec' of typically from 5 to 1,500 Pas,
preferably from 10 to 1,000 Pas, and more preferably from 15 to 500
Pas.
[0147] In the present invention, it is preferable to prepare a
resin composition by adding 1 wt. part to 50 wt. parts of the
branched PAS resin to 100 wt. parts of the linear PAS resin. The
ratio of the branched PAS resin is preferably from 5 to 40 wt.
parts.
[0148] To this resin composition, various organic or inorganic
fillers can be added. Any filler used in the field, such as a
powdery or granular filler or a fibrous filler, can be used. Among
them, fibrous inorganic fillers such as glass fibers and carbon
fibers are preferred.
[0149] The ratio of the filler is typically 400 wt. parts or less,
preferably 350 wt. parts or less, and more preferably 300 wt. parts
or less with respect to 100 wt. parts of the linear PAS resin. When
the filler is added, the lower limit is typically 0.01 wt. part
with respect to 100 wt. parts of the linear PAS resin and is 0.1
wt. part in many cases. The ratio of the filler can be determined
within the above range, if appropriate, depending on the intended
use thereof.
EXAMPLES
[0150] The present invention will be more specifically described
hereinafter with reference to working examples and comparative
examples. The method for measuring physical properties and
characteristics is as follows.
(1) Method for Measuring Halogen Content
[0151] The chlorine content was measured by combustion ion
chromatography as the halogen content in the sample polymer.
(Measurement Conditions)
[0152] Ion chromatograph: DX320 manufactured by DIONEX Pretreatment
devices for combustion: AQF-100, ABC, WS-100 and GA-100,
manufactured by Mitsubishi Chemical Corporation
Sample: 10 mg
Heater: Inlet Temp/900.degree. C., Outlet Temp/1000.degree. C.
[0153] Absorption solution: H.sub.2O.sub.2 900 ppm, internal
standard: PO.sub.4.sup.3-25 ppm
(2) Yield:
[0154] The yield of the polymer was obtained by using the polymer
weight (theoretical amount) when the total amount of the effective
sulfur component (effective S) present in the reactor after the
dehydration step was assumed to be converted to a polymer as a
standard value and calculating the ratio (wt %) of the actual
weight of the polymer recovered to the standard value.
(3) Melt Viscosity:
(3-1) Melt Viscosity A:
[0155] The melt viscosity of a sample (about 10 g of polymer) was
measured with Capirograph 1-C (manufactured by Toyo Seiki
Seisaku-sho, Ltd.). At that time, the used capillary was a die with
an entrance angle (2.095 mm in diameter and 8.04 mm in length). The
measurement temperature was 330.degree. C. The polymer sample was
placed in the device and kept for 5 minutes. Thereafter, the melt
viscosity was measured at a shear rate of 2 sec.sup.-1. The melt
viscosity is referred to as "melt viscosity A".
(3-2) Melt Viscosity B
[0156] The melt viscosity of a sample (about 10 g of polymer) was
measured with Capirograph 1-C (manufactured by Toyo Seiki
Seisaku-sho, Ltd.). The used capillary was a flat die (1 mm in
diameter and 10 mm in length). The measurement temperature was
310.degree. C. The polymer sample was placed in the device and kept
at 310.degree. C. for 5 minutes. Thereafter, the melt viscosity was
measured at a shear rate of 1,200 sec.sup.-1. The melt viscosity is
referred to as "melt viscosity B".
(4) Melt Viscoelasticity (tan .delta.):
[0157] A sample (about 3 g of polymer) was hot pressed in a
circular mold having a diameter of 2 cm at 320.degree. C. and
quenched with ice water to produce a test piece for rheometer
measurement. The melt viscoelasticity was measured using a parallel
plate rheometer (RDSII, manufactured by Rheometric Scientific,
Inc.) at a measurement temperature of 310.degree. C. and an angular
velocity co of 1 rad/sec.
(5) Burr Characteristics
[0158] To 100 wt. parts of linear PPS resin having a melt viscosity
30 Pas as measured at a temperature of 310.degree. C. and a shear
rate of 1,200 sec.sup.-1, 20 wt. parts of a sample polymer and 80
wt. parts of a glass fiber (of 13 .mu.m in diameter and 3 mm in
length, manufactured by Nippon Electric Glass Co., Ltd.) were
added, which was mixed for 2 minutes. This mixture was fed to a
biaxial extruder at a cylinder temperature of 320.degree. C. to
produce a resin composition pellet. This pellet was injected into a
metal mold for evaluation of burrs having a cavity with a diameter
of 70 mm and a thickness of 3 mm at the minimum pressure that the
resin composition was completely filled into the mold. The
injection molding conditions are described below.
<Injection Molding Conditions>
[0159] Injection molder: IS-75E, manufactured by TOSHIBA MACHINE
CO., LTD Cylinder temperature conditions:
NH/H1/H2/H3/H4=310/320/310/300/290 (.degree. C.) Metal mold
temperature: 140.degree. C.
<Measurement of Burr Length>
[0160] The length of burr on a 20 .mu.m.times.5 mm slit (burr
length) formed around the metal mold was measured using an
enlarging projector. The shorter the length of burr the more
excellent the burr suppressing effect (burr characteristics).
(6) Surface Properties of Molded Product
[0161] Both surfaces of a molded product for evaluation of burrs (a
disk with a diameter of 70 mm and a thickness of 3 mm) were
visually observed and evaluated based on the following
criteria:
A: the number of small recesses having a crater shape is 4 or less;
B: the number of recesses having a crater shape is from 5 to 20;
and C: the number of recesses having a crater shape is 21 or
greater.
(7) Yield
[0162] The yield of the polymer was obtained by using the polymer
weight (theoretical amount) when the total amount of the effective
sulfur component (effective S) present in the reactor after the
dehydration step was assumed to be converted to a polymer as a
standard value and calculating the ratio (wt %) of the actual
weight of the polymer recovered to the standard value.
(8) Average Particle Size
[0163] Nine sieves of a sieve having a mesh size of 200, a sieve
having a mesh size of 150, a sieve having a mesh size of 100, a
sieve having a mesh size of 60, a sieve having a mesh size of 32, a
sieve having a mesh size of 24, a sieve having a mesh size of 16, a
sieve having a mesh size of 12 and a sieve having a mesh size of 7
are stacked in this order, a polymer was placed on the top of the
stacked sieves, and the average particle size was measured in
accordance with JIS K-0069.
Working Example 1
(1) Dehydration Step
[0164] 1,950 g of a sodium hydrosulfide (NaSH) solution with a
concentration of 61.8 wt % as analyzed by iodometry (NaSH unit:
21.50 mol), 1,191 g of a sodium hydroxide (NaOH) solution with a
concentration of 73.7 wt % (NaOH unit: 21.94 mol) and 6,000 g of
N-methyl-2-pyrrolidone (hereinafter abbreviated as "NMP") were
charged into a 20 L titanium lined autoclave with a stirrer
(hereinafter abbreviated as "reactor").
[0165] The inside of the reactor was replaced with nitrogen gas.
Thereafter, the temperature of the reactor was increased to
200.degree. C. over about 4 hours while the reactor was stirred.
Thus, 985 g of water and 891 g of NMP were distilled. At that time,
12.5 g of hydrogen sulfide (H.sub.2S) (0.37 mol) was flowed
(vaporized). Therefore, the amount of effective S in the reactor
after the dehydration step was 21.13 mol (the effective amount of S
corresponds to the charged sulfur source).
(2) Charging Step
[0166] After the dehydration step, the content remaining in the
reactor including the effective S (21.13 mol) was cooled to
150.degree. C. 3,094 g of p-dichlorobenzene (hereinafter
abbreviated as "pDCB") [the ratio of pDCB to the effective S=0.996
(mol/mol)], 2,603 g of NMP [added in such a manner that the ratio
of NMP to the effective S in the reactor was 365 (g/mol)] and 170 g
of water [added in such a manner that the ratio of the total amount
of water to the effective S in the reactor was 1.62 (mol/mol) were
added, and then 1.5 g (0.04 mol) of NaOH was added in such a manner
that the ratio of NaOH to the effective S in the reactor was 1.075
(mol/mol). The NaOH (0.73 mol) generated when H.sub.2S vaporized
was included in the reactor.
(3) Polymerization Step
[0167] The stirrer attached to the reactor was stirred at 250 rpm
to perform a reaction at 220.degree. C. for 8 hours. The conversion
ratio of pDCB was 96%. Then, a mixture of 46.1 g of diphenyl
disulfide (hereinafter abbreviated as "DPDS") and 340 g of NMP was
injected into the reactor and reacted for 1 hour. The ratio of DPDS
to the effective S was 0.010 (mol/mol). Further, the prestage
polymerization was carried out by injecting a mixture of 100 g of
1,2,4-trichlorobenzene (hereinafter abbreviated as "TCB") [the
ratio of TCB to the effective S=0.026 (mol/mol)] and 400 g of NMP
into the reactor and reacting the resulting mixture for 15 minutes.
At that time, the total amount of chlorine in pDCB and TCB was
1.035 mol per mol of effective S. The ratio of TCB to DPDS
(mol/mol) was 2.6.
[0168] After that, the poststage polymerization was carried out by
increasing the number of rotations to 400 rpm, injecting 392 g of
water into the reactor, increasing the temperature to 255.degree.
C., and reacting for 3 hours. The ratio of water to the effective S
(mol/mol) was 2.65.
(4) Posttreatment Step
[0169] After the completion of poststage polymerization, a reaction
mixture was cooled to near room temperature. Then, the granular
polymer was screened by passing the content through a 100 mesh
screen (with a sieve opening of 150 .mu.m). The separated polymer
was washed 3 times with acetone and washed 3 times with water. The
granular polymer was washed once with an acetic acid solution whose
pH was adjusted to 4 and further washed 3 times with water, whereby
a washed polymer was obtained. The washed polymer was dried at
100.degree. C. one whole day and night. The yield of granular
polymer was 82%. The average particle size was 633 p.m.
[0170] The resulting branched PAS resin including an --S--
substituent group with a cleaved disulfide compound had a melt
viscosity A (as measured at a temperature of 330.degree. C. and a
shear rate of 2 sec.sup.-1)) of 180,000 Pas, a melt viscosity B (as
measured at a temperature of 310.degree. C. and a shear rate of
1,200 sec.sup.-1) of 1.019 Pas, a chlorine content of 1,000 ppm and
a melt viscoelasticity tan .delta. of 0.27. The data was shown in
Table 1.
Working Example 2
[0171] A polymer was produced in the same manner as in Working
Example 1 except that the amount of DPDS in the polymerization step
of Working Example 1 was 34.5 g and the ratio of DPDS to the
effective S (mol/mol) was 0.0075. The ratio of TCB to DPDS
(mol/mol) was 3.5. The yield of granular polymer was 80%. The
average particle size was 504 p.m.
[0172] The resulting branched PAS resin including an --S--
substituent group with a cleaved disulfide compound had a melt
viscosity A of 300,000 Pas, a melt viscosity B of 1,427 Pas, a
chlorine content of 1,550 ppm and a melt viscoelasticity tan
.delta. of 0.20. The data was shown in Table 1.
Working Example 3
[0173] A polymer was produced in the same manner as in Working
Example 1 except that the amount of DPDS in the polymerization step
of Working Example 1 was 23.1 g and the ratio of DPDS to the
effective S (mol/mol) was 0.005. The ratio of TCB to DPDS (mol/mol)
was 5.2. The yield of granular polymer was 78%. The average
particle size was 320 p.m.
[0174] The resulting branched PAS resin including an --S--
substituent group with a cleaved disulfide compound had a melt
viscosity A of 460,000 Pas, a chlorine content of 1,650 ppm and a
melt viscoelasticity tan .delta. of 0.14. The melt viscosity B was
too high to measure. The data was shown in Table 1.
Working Example 4
(1) Dehydration Step
[0175] 1,870 g of an NaSH solution with a concentration of 61.8 wt
% as analyzed by iodometry (NaSH unit: 20.61 mol) and 1,071 g of an
NaOH solution with a concentration of 73.7 wt % (NaOH unit: 19.73
mol) were charged together with 6,003 g of NMP into a reactor.
[0176] The inside of the reactor was replaced with nitrogen gas.
Thereafter, the temperature of the reactor was increased to
200.degree. C. over about 4 hours while the reactor was stirred.
Thus, 920 g of water and 821 g of NMP were distilled. At that time,
8.0 g of H.sub.2S (0.23 mol) was flowed (vaporized). Therefore, the
amount of effective S in the reactor after the dehydration step was
20.38 mol.
(2) Charging Step
[0177] After the dehydration step, the content remaining in the
reactor including the effective S (20.38 mol) was cooled to
150.degree. C. 2,975 g of p-dichlorobenzene (hereinafter
abbreviated as "pDCB") [the ratio of pDCB to the effective S=0.993
(mol/mol)], 2,248 g of NMP [added in such a manner that the ratio
of NMP to the effective S in the reactor was 365 (g/mol)] and 150 g
of water [added in such a manner that the ratio of the total amount
of water to the effective S in the reactor was 1.60 (mol/mol) were
added, and then 56 g (1.4 mol) of NaOH was added in such a manner
that the ratio of NaOH to the effective S in the reactor was 1.060
(mol/mol). The NaOH (0.47 mol) generated when H.sub.2S vaporized
was included in the reactor.
(3) Polymerization Step
[0178] The stirrer attached to the reactor was stirred at 250 rpm
to perform a reaction at 220.degree. C. for 8 hours. The conversion
ratio of pDCB was 96%. Then, a mixture of 44.4 g of DPDS and 313 g
of NMP was injected into the reactor and reacted for 30 minutes.
The ratio of DPDS to the effective S was 0.010 (mol/mol). Further,
the prestage polymerization was carried out by injecting a mixture
of 76 g of TCB [the ratio of TCB to the effective S=0.021
(mol/mol)] and 400 g of NMP into the reactor and reacting the
resulting mixture for 1 hour. At that time, the total amount of
chlorine in pDCB and TCB was 1.024 mol per mol of effective S.
[0179] The ratio of TCB to DPDS (mol/mol) was 2.06.
[0180] After that, the poststage polymerization was carried out by
increasing the number of rotations to 400 rpm, injecting 513 g of
water into the reactor, increasing the temperature to 255.degree.
C., and reacting for 3 hours. The ratio of water to the effective S
(mol/mol) was 3.00.
(4) Posttreatment Step:
[0181] After the completion of poststage polymerization, a granular
polymer was produced in the same manner as in Working Example 1.
The yield of granular polymer was 82%. The average particle size
was 870 .mu.m.
[0182] The resulting branched PAS resin including an --S--
substituent group with a cleaved disulfide compound had a melt
viscosity A of 45,000 Pas, a melt viscosity B of 560 Pas, a
chlorine content of 1,650 ppm and a melt viscoelasticity tan
.delta. of 0.55.
[0183] The data was shown in Table 1.
Working Example 5
[0184] A polymer was produced in the same manner as in Working
Example 4 except that the amount of DPDS in the polymerization step
of Working Example 4 was 22.0 g and the ratio of DPDS to the
effective S (mol/mol) was 0.005.
[0185] The ratio of TCB to DPDS (mol/mol) was 4.2. The yield of
granular polymer was 86%. The average particle size was 403
.mu.m.
[0186] The resulting branched PAS resin including an --S--
substituent group with a cleaved disulfide compound had a melt
viscosity A of 150,000 Pas, a melt viscosity B of 1,108 Pas, a
chlorine content of 1,600 ppm and a melt viscoelasticity tan
.delta. of 0.28. The data was shown in Table 1.
Working Example 6
[0187] A polymer was produced in the same manner as in Working
Example 4 except that the amount of DPDS in the polymerization step
of Working Example 4 was set to 6.6 g, whereby the ratio of DPDS to
the effective S (mol/mol) was 0.0015, and the amount of TCB was set
to 51.7 g, whereby the ratio of TCB to the effective S (mol/mol)
was 0.014. The total amount of chlorine in pDCB and TCB was 1.014
mol per mol of effective S.
[0188] The ratio of TCB to DPDS (mol/mol) was 9.4.
[0189] The yield of granular polymer was 83%. The average particle
size was 280 p.m.
[0190] The resulting branched PAS resin including an --S--
substituent group with a cleaved disulfide compound had a melt
viscosity A of 130,000 Pas, a melt viscosity B of 1,372 Pas, a
chlorine content of 1,400 ppm and a melt viscoelasticity tan
.delta. of 0.40.
[0191] The data was shown in Table 1.
Comparative Example 1
(1) Dehydration Step
[0192] 1,871 g of an NaSH solution with a concentration of 61.8 wt
% as analyzed by iodometry (NaSH unit: 20.63 mol) and 1,100 g of an
NaOH solution with a concentration of 73.7 wt % (NaOH unit: 20.27
mol) were charged together with 6,501 g of NMP into a reactor.
[0193] The inside of the reactor was replaced with nitrogen gas.
Thereafter, the temperature of the reactor was increased to
200.degree. C. over about 4 hours while the reactor was stirred.
Thus, 953 g of water and 878 g of NMP were distilled. At that time,
13.0 g of hydrogen sulfide (H.sub.2S) (0.38 mol) was flowed
(vaporized). Therefore, the amount of effective S in the reactor
after the dehydration step was 20.24 mol.
(2) Charging Step
[0194] After the dehydration step, the content remaining in the
reactor including the effective S (24.24 mol) was cooled to
150.degree. C. 3,190 g of pDCB [the ratio of pDCB to effective
S=1.072 (mol/mol)], 3,100 g of NMP [the ratio of NMP to the
effective S in the reactor=430 (g/mol)] and 151 g of water [the
ratio of the total amount of water to the effective S in the
reactor=1.54 (mol/mol)] were added [the ratio of NaOH to the
effective S in the reactor=1.039 (mol/mol)]. The NaOH (0.76 mol)
generated when H.sub.2S vaporized is included in the reactor.
(3) Polymerization Step
[0195] The stirrer attached to the reactor was stirred at 250 rpm
to perform a reaction at 220.degree. C. for 3 hours. The conversion
ratio of pDCB was 80%. Then, the prestage polymerization was
carried out by injecting 125 g of TCB [the ratio of TCB to the
effective S=0.034 (mol/mol)] and 406 g of NMP into the reactor and
reacting the resulting mixture for 4 hours. At that time, the total
amount of chlorine in pDCB and TCB was 1.123 mol per mol of
effective S.
[0196] After that, the poststage polymerization was carried out by
increasing the number of rotations to 400 rpm, injecting 603 g of
water into the reactor, increasing the temperature to 255.degree.
C., and reacting for 4 hours. The ratio of water to the effective S
(mol/mol) was 3.19.
(4) Posttreatment Step
[0197] After the completion of poststage polymerization, a granular
polymer was produced in the same manner as in Working Example 1.
The yield of the thus obtained granular polymer was 85%. The
average particle size was 597 .mu.m.
[0198] The resulting branched PAS resin had a melt viscosity A of
280,000 Pas, a melt viscosity B of 750 Pas, a chlorine content of
6,500 ppm and a melt viscoelasticity tan .delta. of 0.15. The data
was shown in Table 1.
Comparative Example 2
[0199] A polymer was produced in the same manner as in Working
Example 1 except that the amount of DPDS in the polymerization step
of Working Example 1 was 9.0 g and the ratio of DPDS to the
effective S (mol/mol) was 0.002. The ratio of TCB to DPDS (mol/mol)
was 13.4. The yield of granular polymer was 56%. The average
particle size was 240 p.m.
[0200] The resulting branched PAS resin including an --S--
substituent group with a cleaved disulfide compound had a melt
viscosity A of 640,000 Pas, a chlorine content of 1,850 ppm and a
melt viscoelasticity tan .delta. of 0.12. The melt viscosity B was
too high to measure. The data was shown in Table 1.
Comparative Example 3
(1) Dehydration Step
[0201] 1,801 g of an NaSH solution with a concentration of 61.8 wt
% as analyzed by iodometry (NaSH unit: 19.85 mol) and 1,080 g of an
NaOH solution with a concentration of 73.7 wt % (NaOH unit: 19.90
mol) were charged together with 6,000 g of NMP into a reactor.
[0202] The inside of the reactor was replaced with nitrogen gas.
Thereafter, the temperature of the reactor was increased to
200.degree. C. over about 4 hours while the reactor was stirred.
Thus, 861 g of water and 718 g of NMP were distilled. At that time,
6.0 g of hydrogen sulfide (H.sub.2S) (0.18 mol) was flowed
(vaporized). Therefore, the amount of effective S in the reactor
after the dehydration step was 19.68 mol
(2) Charging Step
[0203] After the dehydration step, the content remaining in the
reactor including the effective S (19.68 mol) was cooled to
150.degree. C. 3,074 g of pDCB [the ratio of pDCB to the effective
S=1.063 (mol/mol)], 3,580 g of NMP [added in such a manner that the
ratio of NMP to the effective S in the reactor was 450 (g/mol)] and
110 g of water [added in such a manner that the ratio of the total
amount of water to the effective S in the reactor was 1.62
(mol/mol) were added, and then 19.5 g of NaOH was added in such a
manner that the ratio of NaOH to the effective S in the reactor was
1.054 (mol/mol). The NaOH (0.35 mol) generated when H.sub.2S
vaporized is included in the reactor.
(3) Polymerization Step
[0204] The stirrer attached to the reactor was stirred at 250 rpm
to perform a reaction at 220.degree. C. for 8 hours. The conversion
ratio of pDCB was 90%. Then, the prestage polymerization was
carried out by injecting 185 g of TCB [the ratio of TCB to the
effective S=0.052 (mol/mol)] and 400 g of NMP into the reactor. At
that time, the total amount of chlorine in pDCB and TCB was 1.140
mol per mol of effective S.
[0205] After that, the poststage polymerization was carried out by
increasing the number of rotations to 400 rpm, injecting 589 g of
water into the reactor, increasing the temperature to 255.degree.
C., and reacting for 4 hours. The ratio of water to the effective S
(mol/mol) was 3.28.
(4) Posttreatment Step
[0206] After the completion of poststage polymerization, a granular
polymer was produced in the same manner as in Working Example 1.
The yield of granular polymer was 76%. The average particle size
was 623 .mu.m.
[0207] The resulting branched PAS resin had a melt viscosity A of
105,000 Pas, a melt viscosity B of 521 Pas, a chlorine content of
9,000 ppm and a melt viscoelasticity tan .delta. of 0.28. The data
was shown in Table 1.
Comparative Example 4
[0208] The dehydration step was the same as that of Comparative
Example 3, and the preparation step, the polymerization step and
the posttreatment step were as follows.
(2) Charging Step
[0209] After the dehydration step, the content remaining in the
reactor including the effective S (19.68 mol) was cooled to
150.degree. C. 2,997 g of pDCB [the ratio of pDCB to the effective
S=1.036 (mol/mol)], 3,580 g of NMP [added in such a manner that the
ratio of NMP to the effective S in the reactor was 450 (g/mol)], 49
g of TCB [the ratio of TCB to the effective S=0.014 (mol/mol)] and
115 g of water [added in such a manner that the ratio of the total
amount of water to the effective S in the reactor was 1.63
(mol/mol) were added, and then 19.5 g of NaOH was added in such a
manner that the ratio of NaOH to the effective S in the reactor was
1.054 (mol/mol). The NaOH (0.49 mol) generated when H.sub.2S
vaporized is included in the reactor. At that time, the total
amount of chlorine in pDCB and TCB was 1.057 mol per mol of
effective S.
(3) Polymerization Step:
[0210] The stirrer attached to the reactor was stirred at 250 rpm
to perform a reaction at 220.degree. C. for 3 hours. The conversion
ratio of pDCB was 90%. After that, the poststage polymerization was
carried out by increasing the number of rotations to 400 rpm,
injecting 892 g of water into the reactor, increasing the
temperature to 255.degree. C., and reacting for 1 hour. The ratio
of water to the effective S (mol/mol) was 4.15.
(4) Posttreatment Step:
[0211] After the completion of poststage polymerization, a granular
polymer was produced in the same manner as in Working Example 1.
The yield of granular polymer was 80%. The average particle size
was 477 .mu.m.
[0212] The resulting branched PAS resin had a melt viscosity A of
240,000 Pas, a melt viscosity B of 1,210 Pas, a chlorine content of
4,300 ppm and a melt viscoelasticity tan .delta. of 0.37. The data
was shown in Table 1.
Comparative Example 5
[0213] A polymer was produced in the same manner as in Comparative
Example 4 except that the amount of pDCB in the preparation step of
Comparative Example 4 was set to 3,065 g, whereby the ratio of pDCB
to the effective S (mol/mol) was 1.060, and the amount of TCB was
set to 108 g, whereby the ratio of TCB to the effective S (mol/mol)
was 0.030.
[0214] At that time, the total amount of chlorine in pDCB and TCB
was 1.105 mol per mol of effective S. The yield of granular polymer
was 77%. The average particle size was 241 p.m.
[0215] The resulting branched PAS resin had a melt viscosity A of
490,000 Pas, a chlorine content of 8,300 ppm and a melt
viscoelasticity tan .delta. of 0.05. The melt viscosity B was too
high to measure.
Comparative Example 6
(1) Dehydration Step
[0216] 2,000 g of an NaSH solution with a concentration of 61.8 wt
% as analyzed by iodometry (NaSH unit: 22.05 mol) and 1,171 g of an
NaOH solution with a concentration of 73.7 wt % (NaOH unit: 21.58
mol) were charged together with 6,001 g of NMP into a reactor.
[0217] The inside of the reactor was replaced with nitrogen gas.
Thereafter, the temperature of the reactor was increased to
200.degree. C. over about 4 hours while the reactor was stirred.
Thus, 1014 g of water and 763 g of NMP were distilled. At that
time, 5.5 g of hydrogen sulfide (H.sub.2S) (0.16 mol) was flowed
(vaporized). Therefore, the amount of effective S in the reactor
after the dehydration step was 21.89 mol.
(2) Charging Step
[0218] After the dehydration step, the content remaining in the
reactor including the effective S (21.89 mol) was cooled to
150.degree. C. 3,283 g of pDCB [the ratio of pDCB to the effective
S=1.020 (mol/mol)], 2,760 g of NMP [added in such a manner that the
ratio of NMP to the effective S in the reactor was 365 (g/mol)] and
189 g of water [added in such a manner that the ratio of the total
amount of water to the effective S in the reactor was 1.62
(mol/mol) were added, and then 43.0 g of NaOH was added in such a
manner that the ratio of NaOH to the effective S in the reactor was
1.050 (mol/mol). The NaOH (0.32 mol) generated when H.sub.2S
vaporized is included in the reactor.
(3) Polymerization Step
[0219] The stirrer attached to the reactor was stirred at 250 rpm
to perform a reaction at 220.degree. C. for 5 hours. The conversion
ratio of pDCB was 92%.
[0220] Then, the prestage polymerization was carried out by
injecting 14.3 g of DPDS and 762 g of NMP into the reactor and
reacting the resulting mixture for 15 minutes. The ratio of DPDS to
the effective S (mol/mol) was 0.003.
[0221] After that, the poststage polymerization was carried out by
increasing the number of rotations to 400 rpm, injecting 397 g of
water into the reactor, increasing the temperature to 255.degree.
C., and reacting for 5 hours. The ratio of water to the effective S
(mol/mol) was 2.63.
(4) Posttreatment Step
[0222] After the completion of poststage polymerization, a granular
polymer was produced in the same manner as in Working Example 1.
The yield of granular polymer was 89%. The average particle size
was 436 .mu.m.
[0223] The resulting PAS resin including an --S-- substituent group
with a cleaved disulfide compound had a melt viscosity B of 19 Pas
and a chlorine content of 950 ppm. The melt viscoelasticity tan
.delta. was too low to measure. The data was shown in Table 1.
[0224] Working Examples 1 to 6 and Comparative Examples 1 to 6 are
arranged in Table 1.
TABLE-US-00001 TABLE 1-I Conversion TCB/ pDCB/S ratio of TCB/S
DPDS/S DPDS (mol/ pDCB (mol/ (mol/ (mol/ Smol) (%) Smol) Smol) mol)
Working 0.996 96 0.026 0.010 2.6 Example 1 Working 0.996 96 0.026
0.0075 3.5 Example 2 Working 0.996 96 0.026 0.005 5.2 Example 3
Working 0.993 96 0.021 0.010 2.1 Example 4 Working 0.993 96 0.021
0.005 4.2 Example 5 Working 0.993 96 0.014 0.0015 9.4 Example 6
Comparative 1.072 80 0.034 Not -- Example 1 added Comparative 0.996
96 0.026 0.002 13.4 Example 2 Comparative 1.063 90 0.052 Not --
Example 3 added Comparative 1.036 90 0.014 Not -- Example 4 (added
in added the charging step) Comparative 1.060 90 0.030 Not --
Example 5 (added in added the charging step) Comparative 1.020 92
Not 0.003 -- Example 6 added
TABLE-US-00002 TABLE 1-II Melt Melt viscosity viscosity Cl Melt
Burr A B content viscoelasticity length Surface (Pa s) (Pa s) (ppm)
tan.delta. (.mu.m) properties Working 180,000 1,019 1,000 0.27 50 A
Example 1 Working 300,000 1,427 1,550 0.20 70 A Example 2 Working
460,000 Unmeasurable 1,650 0.14 100 B Example 3 Working 45,000 560
1,650 0.55 110 A Example 4 Working 150,000 1,108 1,600 0.28 70 A
Example 5 Working 130,000 1,372 1,400 0.40 80 A Example 6
Comparative 280,000 750 6,500 0.15 90 A Example 1 Comparative
640,000 Unmeasurable 1,850 0.12 150 C Example 2 Comparative 105,000
521 9,000 0.28 150 A Example 3 Comparative 240,000 1,210 4,300 0.37
170 B Example 4 Comparative 490,000 Unmeasurable 8,300 0.05 180 C
Example 5 Comparative Unmeasurable 19 950 -- -- -- Example 6
Discussion
[0225] When a case of the present invention (Working Example 1 or
2) and a case in which the disulfide compound was not added
(Comparative Example 1) are compared as examples having a certain
level of melt viscosity, melt viscoelasticity tan .delta. and burr
length characteristics, the case of the present invention (Working
Example 1 or 2) is more excellent than the case in which the
disulfide compound was not added (Comparative Example 1) in terms
of the fact that the chlorine content is remarkably low and the
burr length is short.
[0226] Comparative Example 2 is a case in which a small amount of
the disulfide compound was added in the present invention (Working
Examples 1, 2 and 3). In this case, particularly a ratio of the
polyhalo aromatic compound to the disulfide compound being 12 or
greater is outside the range of the present invention. The melt
viscosity A of Comparative Example 2 is greater than the range of
the present invention, thereby making it impossible to measure the
melt viscosity B. It is clear that it is not practical as a burr
suppressor. When a case of the present invention (Working Example
4) and a case in which the disulfide compound was not added
(Comparative Example 3 or 4) are compared as examples having a
certain level of low melt viscosity and high melt viscoelasticity
tan .delta., the case of the present invention (Working Example 4)
is more excellent than the case in which the disulfide compound was
not added (Comparative Example 3 or 4) in terms of the fact that
not only the chlorine content is low but also the burr length is
particularly short.
[0227] Particularly, despite the fact that the melt viscosity A of
Working Example 4 is as remarkably low as 45,000 Pas, the burr
length is 110 .mu.m and an effect on the suppression of burrs is
given.
[0228] When a case of the present invention (Working Example 3) and
a case (Comparative Example 5) in which the disulfide compound was
not added are compared as examples having a certain level of high
melt viscosity, the present invention (Working Example 3) is
excellent in terms of the fact that the chlorine content is low,
and particularly the burr length is short.
[0229] Comparative Example 5 is a case in which the disulfide
compound was not added and the polyhalo aromatic compound was added
in the charging step, and is poor in terms of the fact that the
chlorine content is high and the burr length is long.
[0230] Comparative Example 6 is a case in which the disulfide
compound was added, but the polyhalo aromatic compound was not
added, and is not a branched PAS resin. This case is poor in terms
of the fact that the melt viscosity A is too low to measure.
INDUSTRIAL APPLICABILITY
[0231] In the branched PAS resin including an --S-- substituent
group with a cleaved disulfide compound of the present invention,
the halogen (chlorine) content is low, it is possible to
rationalize the melt viscosity and it is possible to realize a
wider range of numerical value of melt viscoelasticity tan .delta.
which is an indicator of branched structure. Further, the branched
PAS resin including an --S-- substituent group with a cleaved
disulfide compound of the present invention is useful as the burr
suppressor.
[0232] The branched PAS resin including an --S-- substituent group
with a cleaved disulfide compound of the present invention can be
blended with another thermoplastic resin such as a linear PAS resin
and formed into various molded products such as films, sheets and
fibers by a general melt molding method such as injection molding,
extrusion molding or compression molding. Further, the resin can be
used as a material for resin parts in a wide range of fields
including electrical and electric devices, automobile devices and
chemical devices.
* * * * *