WO1991009072A1 - Process for the preparation of copoly(arylene sulfide) having an increased amount of disulfide radicals - Google Patents

Process for the preparation of copoly(arylene sulfide) having an increased amount of disulfide radicals Download PDF

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Publication number
WO1991009072A1
WO1991009072A1 PCT/US1990/007250 US9007250W WO9109072A1 WO 1991009072 A1 WO1991009072 A1 WO 1991009072A1 US 9007250 W US9007250 W US 9007250W WO 9109072 A1 WO9109072 A1 WO 9109072A1
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Prior art keywords
copoly
arylene sulfide
disulfide
range
aromatic radical
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PCT/US1990/007250
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French (fr)
Inventor
Joseph John Watkins
David Richard Fagerburg
Paul Blakney Lawrence
Mark Rule
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Eastman Kodak Company
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Publication of WO1991009072A1 publication Critical patent/WO1991009072A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G75/00—Macromolecular compounds obtained by reactions forming a linkage containing sulfur with or without nitrogen, oxygen, or carbon in the main chain of the macromolecule
    • C08G75/02—Polythioethers
    • C08G75/0204—Polyarylenethioethers
    • C08G75/0286—Chemical after-treatment
    • C08G75/0295—Modification with inorganic compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G75/00—Macromolecular compounds obtained by reactions forming a linkage containing sulfur with or without nitrogen, oxygen, or carbon in the main chain of the macromolecule
    • C08G75/02—Polythioethers
    • C08G75/0204—Polyarylenethioethers
    • C08G75/025—Preparatory processes
    • C08G75/0263—Preparatory processes using elemental sulfur
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G75/00—Macromolecular compounds obtained by reactions forming a linkage containing sulfur with or without nitrogen, oxygen, or carbon in the main chain of the macromolecule
    • C08G75/14—Polysulfides

Definitions

  • the invention relates to a process for the preparation of a copoly(arylene sulfide) having a increased amount of disulfide radicals by heating a disulfide radical increasable copoly(arylene sulfide) in the melt phase in the presence of sulfur.
  • Poly(arylene sulfide) resins are thermosetting- thermoplastic polymeric materials with good thermal stability, unusual insolubility, resistance to chemical environments and inherent flame resistance. These resins additionally have good electrical insulative properties which make them ideal for electrical and electronic applications. Their excellent resistance to chemical degradation makes them ideal for use in chemical environments which involve organic solvents and strong mineral acids, such as coatings for pipes, tanks, pumps and other equipment.
  • This copol (arylene sulfide) correspond to the structure
  • A is a divalent substituted or unsubstituted aromatic radical
  • x is in the range of 0.50 to 0.001 and n is at least 200.
  • (-A-S-S-) ⁇ is an important feature of this polymer.
  • the amount of disulfide radical be in higher part of the range of 0.5 to 0.001.
  • One approach to obtaining a polymer with the amount of disulfide radicals in the high range is to prepare the polymer originally with the desired high amount of disulfide radicals. This is often difficult because of problems with stoichiometry control during the reactio . If the attempt to prepare a polymer with the desired high amount of disulfide radicals is unsuccessful the polymer is of no value for the particular application requiring the high amount of disulfide radicals and must be discarded or used for some other application.
  • the process of this invention can be thought of as a process for preparation of a copoly(arylene sulfide) which has an increased amount of disulfide radicals and corresponds to the structure
  • A is a divalent substituted or unsubstituted aromatic radical
  • x is in the range of 0.50 to 0.005, preferably 0.30 to .01, and even more preferably 0.20 to 0.02 and n is at least 50, comprising contacting a disulfide radical increasable copoly(arylene sulfide) corresponding to the structure
  • A is a divalent substituted or unsubstituted aromatic radical
  • x is in the range of 0.45 to 0.001, preferably 0.25 to 0.005, and more preferably 0.15 to 0.01 and n is at least 25,
  • Sulfur is reacted as elemental sulfur and may consist of any of the standard forms which are .possible for elemental sulfur. That is, the sulfur may be present in any of its allotropic modification such as orthorhombic cyclooctasulfur (So) or any other cyclic elemental sulfur such as any of the cyclosulfur species having 6-12 sulfur atoms. Additionally, any crystalline form of sulfur may be used in the present reaction. Surprisingly, impurities in the elemental sulfur do not appear to affect the efficiency or selectivity of the present polymerization reaction.
  • the sulfur preferably has a purity of 98%-100%, although sulfur having a lower degree of purity may be used. This lack of sensitivity to the presence of impurities in the sulfur is advantageous to the present process when used as a commercial process since highly purified sulfur is not required and the associated expense is not incurred.
  • the reaction between the disulfide radical increasable copoly(arylene sulfide) and the sulfur is carried out in the melt phase. Preferably, this is accomplished by heating the disulfide radical increasable copoly(arylene sulfide) until it melts and then contacting the molten polymer with the sulfur.
  • the amount of sulfur that is used depends on the difference between the number of disulfide units in the disulfide radical increasable copoly(arylene sulfide) and the number of disulfide units which are desired in the copoly(arylene sulfide) which has an increased amount of disulfide radicals. After the difference in amount of disulfide radicals is determined the theoretical moles of sulfur are calculated. This theoretical amount of sulfur is then added to the molten disulfide radical increasable copoly(arylene sulfide) .
  • the disulfide content of both the original copoly( rylene sulfide) and the resulting copoly(arylene sulfide) is defined as the amount of sulfur which is excess over one sulfur per repeat unit and can be determined via elemental analysis calculation in which the carbon atoms are set equal to exactly six.
  • the process of this invention can be carried out under a wide range of reaction conditions. Broadly, the reaction temperature should be above 250°C and no higher than 375°C. Preferably, the reaction temperature should not be less than 275°C and no more than 350°C and more preferably from 275°C to 325°C.
  • reaction temperature must in any event be high enough to obtain a melt of the disulfide radical increasable copol (arylene sulfide) .
  • Reaction times may vary considerably but must be sufficient to enable thorough melting and then mixing of the reactants, which normally requires at least 5 to 10 minutes . Although in theory an almost infinitely long reaction time could be employed, in practice reactions are carried out for no longer than 8 hours and preferably no longer than 4 hours and more preferably no longer than 2 hours.
  • the utility of the polymer prepared by the process of this invention depends on the chain length, or value of n.
  • n When the value of n is sufficiently low that the polymer is a liquid the polymer can be used as a coating or as a starting material for preparation of a high molecular weight polymer by solid stating or other conventional techniques for molecular weight buildup.
  • the value of n is sufficiently high the polymer is a solid it can be used as a molding plastic or as a starting material for preparation of a polymer of even higher molecular weights by solid starting or other conventional means for increasing the molecular weight.
  • elemental analysis is performed by standard combustion techniques.
  • This example illustrates preparation of a disulfide radical increasable copoly(arylene sulfide) .
  • a disulfide radical increasable copoly(arylene sulfide) Into a 5 liter 3-neck round bottom flask are weighed the following: 380g sulfur (11.9 mol), 4100 g p-diiodobenzene (12.4 mol, 4.9 mol% excess), and 8.0 g of 1,3-diiodo-5-nitrobenzene to act as a catalyst.
  • the flask was fitted with a Vigreux column, a mechanical stirrer through the center joint, and an inlet tube for a slow air sweep.
  • the column was attached via a distillation head and a takeoff tube to a distillation receiver which was cooled in dry ice.
  • the receiver was connected to a vacuum source.
  • the flask was maintained at 200 torr pressure and controlled at 225°C. It was held under these conditions for 2 hours, at which time the bath temperature was raised to 230°C. After 2 hours, the bath temperature was raised to 235°C. After 2 more hours have elapsed (6 hours total time from the reaction start at this point) the pressure was reduced to 120 torr, held for 2 hours and then reduced to 60 torr where it was held for an additional 30 minutes.
  • the reaction flask was removed from the metal bath, repressurized with nitrogen, and allowed to cool under nitrogen.
  • the polymer yield was 130% of a dark polymer with low melt viscosity which did not crystallize. Elemental analysis gave: carbon 60.13%, hydrogen 3.36%, sulfur 25.84%, and iodine 11.11%.
  • the amount of disulfide radicals is calculated to be 0.5 mol percent which corresponds to an x value of .005.
  • This example illustrates preparation of a copoly(arylene sulfide) having an increased amount of disulfide radicals in accordance with this invention.
  • Example 2 Twenty grams of the polymer prepared in Example 1 having 0.5 mol percent disulfide radicals are combined with 0.30 grams sulfur. The sulfur was added to the molten polymer and reacted for 30 minutes at atmosphere pressure at 300°C. The polymer was cooled, and analyzed for disulfide content. The disulfide content of the polymer was 0.03 which corresponds to 3 mol %.

Abstract

A process for preparation of a copoly(arylene sulfide) which has an increased amount of disulfide radicals and corresponds to the structure [(-A-S-)1-x(-A-S-S-)x]n, wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.50 to 0.005 and n is at least 50, comprising contacting a disulfide radical increasable copoly(arylene sulfide) corresponding to the structure [(-A-S-)1-x(-A-S-S-)x]n, wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.45 to 0.001 and n is at least 25, in the melt phase with elemental sulfur for a sufficient period of time and at a temperature above 250 degrees C to increase the molecular weight of the copoly(arylene sulfide).

Description

PROCESS FOR THE PREPARATION
OF COPOLY(ARYLENE SULFIDE) HAVING
AN INCREASED AMOUNT OF DISULFIDE RADICALS
The invention relates to a process for the preparation of a copoly(arylene sulfide) having a increased amount of disulfide radicals by heating a disulfide radical increasable copoly(arylene sulfide) in the melt phase in the presence of sulfur.
Poly(arylene sulfide) resins are thermosetting- thermoplastic polymeric materials with good thermal stability, unusual insolubility, resistance to chemical environments and inherent flame resistance. These resins additionally have good electrical insulative properties which make them ideal for electrical and electronic applications. Their excellent resistance to chemical degradation makes them ideal for use in chemical environments which involve organic solvents and strong mineral acids, such as coatings for pipes, tanks, pumps and other equipment. This copol (arylene sulfide) correspond to the structure
Figure imgf000003_0001
wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.50 to 0.001 and n is at least 200.
The amount of disulfide radical which corresponds to the formula
(-A-S-S-)χ is an important feature of this polymer. For certain applications such as films and fibers it is desirable that the amount of disulfide radical be in higher part of the range of 0.5 to 0.001. One approach to obtaining a polymer with the amount of disulfide radicals in the high range is to prepare the polymer originally with the desired high amount of disulfide radicals. This is often difficult because of problems with stoichiometry control during the reactio . If the attempt to prepare a polymer with the desired high amount of disulfide radicals is unsuccessful the polymer is of no value for the particular application requiring the high amount of disulfide radicals and must be discarded or used for some other application. We have now discovered a way to increase the amount of disulfide radicals if the amount of disulfide radicals in the original polymer is lower than desired. We have discovered that the amount of disulfide radicals can be increased by contacting the polymer with sulfur in the melt phase.
Broadly the process of this invention can be thought of as a process for preparation of a copoly(arylene sulfide) which has an increased amount of disulfide radicals and corresponds to the structure
D (-A-S-)1.χ(-A-S-S-) n wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.50 to 0.005, preferably 0.30 to .01, and even more preferably 0.20 to 0.02 and n is at least 50, comprising contacting a disulfide radical increasable copoly(arylene sulfide) corresponding to the structure
Figure imgf000005_0001
wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.45 to 0.001, preferably 0.25 to 0.005, and more preferably 0.15 to 0.01 and n is at least 25,
in the melt phase with elemented sulfur for a sufficient period of'time and at a temperature above 250 degrees C to increase the molecular weight of the copoly(arylene sulfide) .
Both the original copoly(arylene sulfide) which has the amount of disulfide radicals increased by the process of the invention and the resulting copol (arylene sulfide) which has an increased amount of disulfide radicals are knowned in the art.
Sulfur is reacted as elemental sulfur and may consist of any of the standard forms which are .possible for elemental sulfur. That is, the sulfur may be present in any of its allotropic modification such as orthorhombic cyclooctasulfur (So) or any other cyclic elemental sulfur such as any of the cyclosulfur species having 6-12 sulfur atoms. Additionally, any crystalline form of sulfur may be used in the present reaction. Surprisingly, impurities in the elemental sulfur do not appear to affect the efficiency or selectivity of the present polymerization reaction. The sulfur preferably has a purity of 98%-100%, although sulfur having a lower degree of purity may be used. This lack of sensitivity to the presence of impurities in the sulfur is advantageous to the present process when used as a commercial process since highly purified sulfur is not required and the associated expense is not incurred.
Preferably, the carbon analysis of the sulfur used to prepare the copl (arylene sulfide) is quite low. Specifically, the amount of carbon by combustion or other analysis is less than 0.05, preferably less than 0.025 and more preferably less than 0.01 weight percent, based on the weight of the sulfur.
The reaction between the disulfide radical increasable copoly(arylene sulfide) and the sulfur is carried out in the melt phase. Preferably, this is accomplished by heating the disulfide radical increasable copoly(arylene sulfide) until it melts and then contacting the molten polymer with the sulfur.
The amount of sulfur that is used depends on the difference between the number of disulfide units in the disulfide radical increasable copoly(arylene sulfide) and the number of disulfide units which are desired in the copoly(arylene sulfide) which has an increased amount of disulfide radicals. After the difference in amount of disulfide radicals is determined the theoretical moles of sulfur are calculated. This theoretical amount of sulfur is then added to the molten disulfide radical increasable copoly(arylene sulfide) .
The disulfide content of both the original copoly( rylene sulfide) and the resulting copoly(arylene sulfide) is defined as the amount of sulfur which is excess over one sulfur per repeat unit and can be determined via elemental analysis calculation in which the carbon atoms are set equal to exactly six. The process of this invention can be carried out under a wide range of reaction conditions. Broadly, the reaction temperature should be above 250°C and no higher than 375°C. Preferably, the reaction temperature should not be less than 275°C and no more than 350°C and more preferably from 275°C to 325°C. The reaction temperature must in any event be high enough to obtain a melt of the disulfide radical increasable copol (arylene sulfide) . Reaction times may vary considerably but must be sufficient to enable thorough melting and then mixing of the reactants, which normally requires at least 5 to 10 minutes . Although in theory an almost infinitely long reaction time could be employed, in practice reactions are carried out for no longer than 8 hours and preferably no longer than 4 hours and more preferably no longer than 2 hours.
After the process of this invention has been used to prepare a copoly(arylene sulfide) having an increased amount of disulfide linkage the molecular weight of the polymer can be increased by conventional means, such as solid-state polymerization.
The utility of the polymer prepared by the process of this invention depends on the chain length, or value of n. When the value of n is sufficiently low that the polymer is a liquid the polymer can be used as a coating or as a starting material for preparation of a high molecular weight polymer by solid stating or other conventional techniques for molecular weight buildup. When the value of n is sufficiently high the polymer is a solid it can be used as a molding plastic or as a starting material for preparation of a polymer of even higher molecular weights by solid starting or other conventional means for increasing the molecular weight. In the following examples, elemental analysis is performed by standard combustion techniques.
EXAMPLES
1. This example illustrates preparation of a disulfide radical increasable copoly(arylene sulfide) . Into a 5 liter 3-neck round bottom flask are weighed the following: 380g sulfur (11.9 mol), 4100 g p-diiodobenzene (12.4 mol, 4.9 mol% excess), and 8.0 g of 1,3-diiodo-5-nitrobenzene to act as a catalyst. The flask was fitted with a Vigreux column, a mechanical stirrer through the center joint, and an inlet tube for a slow air sweep. The column was attached via a distillation head and a takeoff tube to a distillation receiver which was cooled in dry ice. The receiver was connected to a vacuum source. The flask was maintained at 200 torr pressure and controlled at 225°C. It was held under these conditions for 2 hours, at which time the bath temperature was raised to 230°C. After 2 hours, the bath temperature was raised to 235°C. After 2 more hours have elapsed (6 hours total time from the reaction start at this point) the pressure was reduced to 120 torr, held for 2 hours and then reduced to 60 torr where it was held for an additional 30 minutes. The reaction flask was removed from the metal bath, repressurized with nitrogen, and allowed to cool under nitrogen. The polymer yield was 130% of a dark polymer with low melt viscosity which did not crystallize. Elemental analysis gave: carbon 60.13%, hydrogen 3.36%, sulfur 25.84%, and iodine 11.11%. The amount of disulfide radicals is calculated to be 0.5 mol percent which corresponds to an x value of .005.
2. This example illustrates preparation of a copoly(arylene sulfide) having an increased amount of disulfide radicals in accordance with this invention.
Twenty grams of the polymer prepared in Example 1 having 0.5 mol percent disulfide radicals are combined with 0.30 grams sulfur. The sulfur was added to the molten polymer and reacted for 30 minutes at atmosphere pressure at 300°C. The polymer was cooled, and analyzed for disulfide content. The disulfide content of the polymer was 0.03 which corresponds to 3 mol %.

Claims

1. A process for preparation of a copoly(arylene sulfide) which has a increased amount of disulfide radicals and corresponds to the structure
Figure imgf000010_0001
wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.50 to 0.005 and n is at least 50,
comprising contacting a disulfide readical increasable copoly(arylene sulfide) corresponding to the structure
(-A-S-)1_χ(-A-S-S-)J n
wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.45 to 0.001 and n is at least 25,
in the melt phase with elemental sulfur for a sufficient period of time and at a temperature above 250 degrees C to increase the molecular weight of the copoly(arylene sulfide) .
2. The process of Claim 1 wherein the divalent aromatic radical A is contributed by a compound selected from the group consisting of diiodobenzenes, diiodonaphthalenes, diiodobiphenyls, diiodotoluenes, diiodophenyl sulfones, and diiodobenzophenones.
3. The process of Claim 1 wherein the divalent aromatic radical A is contributed by a compound selected from the group consisting of p-diiodobenzene, m-diiodobenzene, p,p'- diiodobiphenyl, p,p'-diiododiphenyl ether, 2,6-diiodonaphthalene, (p-iodophenyl) sulfone, and 4,4'-diiodobenzophenone.
4. The process of Claim 1 wherein the temperature is in the range of 275-350°C.
5. The process of Claim 4 wherein the temperature is in the range of 275-325°C.
6. A process for preparation of a copoly(arylene sulfide) which has a increased amount of disulfide radicals and corresponds to the structure
Figure imgf000011_0001
wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.30 to 0.01 and n is at least 50, comprising contacting a disulfide radical increasable copoly(arylene sulfide) corresponding to the structure
[](-A-S-)1.a.(-A-S-S-)J n
wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.25 to 0.005 and n is at least 25,
in the melt phase with elemental sulfur for a sufficient period of time and at a temperature above 250 degree C to increase the molecular weight of the copoly(arylene sulfide) .
7. A process for preparation of a copoly(arylene sulfide) which has a increased amount of disulfide radicals and corresponds to the structure
c (-A-S-);L.χ( ■A-S-S-
Figure imgf000012_0001
n wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.20 to 0.02 and n is at least 50,
comprising contacting a disulfide radical increasable copoly(arylene sulfide) corresponding to the structure
Figure imgf000013_0001
10 wherein A is a divalent substituted or unsubstituted aromatic radical, x is in the range of 0.15 to 0.01 and n is at least 25,
in the melt phase with elemental sulfur for 15 a sufficient period of time and at a temperature above 250 degrees C to increase the molecular weight of the copoly(arylene sulfide) .
PCT/US1990/007250 1989-12-18 1990-12-11 Process for the preparation of copoly(arylene sulfide) having an increased amount of disulfide radicals WO1991009072A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1089983C (en) * 1994-12-20 2002-08-28 日本胜利株式会社 Method and apparatus for limiting band of moving-picture signal

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0193827A1 (en) * 1985-03-06 1986-09-10 Bayer Ag Process for the preparation of high-molecular weight polyarylene sulfides
US4786713A (en) * 1987-11-06 1988-11-22 Eastman Kodak Company Copoly(arylene sulfidex-disulfide)

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0193827A1 (en) * 1985-03-06 1986-09-10 Bayer Ag Process for the preparation of high-molecular weight polyarylene sulfides
US4786713A (en) * 1987-11-06 1988-11-22 Eastman Kodak Company Copoly(arylene sulfidex-disulfide)

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Polymer Degradation and Stability, vol. 11, 1985, Elsevier Applied Science Publishers, Ltd, (GB), M. Wejchan-Judek et al.: "A new method of curing poly(phenylene sulphide)", pages 55-62 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1089983C (en) * 1994-12-20 2002-08-28 日本胜利株式会社 Method and apparatus for limiting band of moving-picture signal

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