Title of Invention

A PROCESS FOR PREPARATION OF POLY(AMIDE)

Abstract A process for preparation of poly(amide) by polymerizing lactams with anionic initiator and, optionally, an activator and in the presence of a polymerizable or polymeric steric stabilizer in an organic solvent and heating the reaction mixture between 70°C and 270°C with stirring from 200 to 800 rpm for a period ranging between 30 minutes and 8 hours and separating the sphereical particles of poly(amide)s by conventional procedures.
Full Text This invention relates to a method for producing poly (amide)s. More particularly it relates to polymerization and/or copolymerization of lactams with 2 to 12 carbon atoms in the ring by ring opening dispersion polymerization in presence of a suitable steric stabilizer, preferably, a polymerizable stabilizer having the formula (I), or an amphiphilic block copolymeric stabilizer.
(Formula Removed)
FORMULA (I)
Poly(amide)s are synthesized by polymerizing lactams by three principal means, namely, hydrolytic, anionic and cationic polymerization depending on the mode of monomer activation. Of these, anionic route is found to be an efficient method of polymerizing lactams. The polymerization is generally carried out in the presence of alkali or alkaline earth metals as initiators and, optionally, in the presence of additional activators at high temperatures.
Poly(amide)s produced by conventional methods mentioned herein above does not produce polymers in paniculate form with uniform size and shape. Polyamides in particle form, either as dry powder or in emulsions, are useful in applications such as, coatings and hot melt adhesives. Nevertheless, many processes have been disclosed in the prior art, wherein, cyclic amides were polymerized in some organic solvents to produce solid
poly(amide) particles. US patent 4,764,424 discloses a process for coating poly(amide)s on glass beads in hydrocarbon solvent without use of any particle stabilizer. US patent 3,910,861 describes a process for producing solid poly(amide) particles using bis caprolactamether as promoter and without any added stabilizer. EP application 256323 discloses a process for producing poly(amide)s in polypropylene as dispersion medium and without any particle stabilizer. US patent 3,879,354 proposes a method of polymerizing lauryllactam using 4,4'-dichlorophenylsulfone as promoter and quenching the reaction with iso-propanol. These processes are, in principle, precipitation polymerization techniques, which do not yield poly(amide) particles in spherical form. Fairly uniform size poly(amide) particles have been obtained by phase separation techniques. [J.Appl.Polym.Sci., 45, 1783 (1992)]. Herein, 1 wt % concentration of poly(amide) polymer is prepared in a suitable solvent. The solution was then quickly cooled. The precipitate is then washed to get spherical poly(amide) particles. The drawback of this technique is the use of excess solvent for dissolution of the polymer particles. Other particle forming lactam polymerization using added particle stabilizer is known in the prior art. In British Patent No. 1,008,001 lactams are polymerized using alkali metals as initiators, isocyanates as activators and in the presence of poly (olefin)s as steric stabilizers. In an another variant, Japanese Patent No. 04072329, alkali metal stearates are used to stabilize the poly(amide) particles. In yet another British Patent 1,095,931 there is disclosed a process for polymerizing caprolactam in mixed aliphatic and aromatic hydrocarbons in the presence of N-methacryloyl caprolactam and methyl methacrylate. US patents 4,734,304 and 4,831,061 disclose a process for producing infusible poly (amide-imide) powders by polymerizing caprolactam in a solvent using
as a dispersing agent. Poly(amide) particles disclosed in the earlier embodiments have a broad particle size distribution (size ranging between 10 and 500 (a). Furthermore, none of the prior method describes the use of a block copolymer or polymerizable type steric stabilizers for stabilizing the poly(amide) particles in non-aqueous dispersing medium.
The main object of the present invention is to provide a process for producing poly(amide)s in particulate form with controlled particle size and shape.
Another object of the present invention is to stabilize poly(amide) particles by ring opening polymerization of lactams that comprises of 2 to 12 carbon atoms in the ring.
Further object of the present invention is to stabilize poly(amide particles using a polymerizable or polymeric steric stabilizers, wherein, the former is incorporated into the polymer backbone by chemical reaction and the latter is adsorbed on the particle surface and thus the particles are prevented from agglomeration by steric stabilization mechanism.
Accordingly, the present invention provides a process for preparation of poly(amide) which comprises polymerizing lactams with anionic initiator and, optionally, an activator and in the presence of a polymerizable or polymeric steric stabilizer in an organic solvent and heating the reaction mixture between 70°C and 270°C with stirring from 200 to 800 rpm for a period ranging between 30 minutes and 8 hours and separating the sphereical particles of poly(amide)s by conventional procedures.
In one of the embodiment of the present invention the lactam used herein contains 2 to 12 carbon atoms in the ring and may or may not contain other functional groups, such as pyrrolidones, C-alkylated pyrrolidones, piperidine, butanolactam, pentanolactam, hexanolactam, dodecyllactam and the like.
In another embodiment of the present invention the initiator used may be anionic initiator derived from compounds which are capable of producing lactam anion which are exemplified by alkali metals, alkali metal hydrides, alcoholates, carbonates, alkali metal salts of diverse weak acids, alkali aluminums, alkali aluminum hydride and their partial or total alkoxides or lactam salts grignard reagents, quaternary ammonium salts of lactams or of their organic compounds and guanidium salts of lactams.
In still another embodiment the activator used may be the strongest alkylating agent for lactam polymerization, exemplified by N-acyl lactams (N-acetyl lactam, N-benzoyl lactams, carbonyl-N,N-bis lactams), compounds containing an electronegatively N-substituted amide groups such as N-cyano lactam, lactam-N-carboxylate esters, compounds containing an imide group, organic or inorganic compounds such as esters, acid halides, anhydrides and isocyanates or diisocyanates capable of forming N-substituted lactam derivatives by reacting with monomer lactam or its alkaline salt.
In yet another embodiment of the present invention, the polymerizable steric stabilizer used is a macromonomer, particularly a macromonomer containing a long chain
hydrophobic moiety with a lactam group at the chain terminal, as mentioned in formula
(I) (Formula Removed)
FORMULA (I)
wherein
R = an alkyl group with 1-40 carbon atoms
R1 = hydrogen or methyl
R2 = alkylene units with 1-5 carbon atoms
X = bifunctional moiety derived from mercaptoacetic acid, 3-mercaptopropionic acid,
mercaptosuccinic acid, n = 3-45 m = > 2 methylene units attached to the hetero atom
The preparation of which have been claimed and disclosed in our co-pending application NF-299/00.
In another embodiment of the present invention, the polymeric steric stabilizer used is a block copolymer prepared via sequential anionic polymerization technique having a block of hydrophobic repeating unit which may be exemplified by poly(isoprene), poly(butadiene) or their hydrogenated analogues, poly(dimethysiloxane) with a number average molecular weight preferably 1000 to 50000 and more preferably between 2000
and 15000 and having a block of hydrophilic repeating unit with a number average molecular weight preferably 200 to 20000 and more preferably between 1000 and 5000, the hydrophilic blocks are exemplified by poly(alkylene oxide) like poly(ethylene oxide), poly(propylene oxide) and poly(tetramethylene oxide).
In another embodiment of the present invention, the organic solvent used may be non reactive and good solvent for the monomers and non-solvent for the polymer particles, which may be exemplified by aliphatic hydrocarbons such as hexane, heptane, octane, decane, isooctane, dodecane, hexadecane, superior kerosene, paraffin oil, white mineral oil, and aromatic hydrocarbons such as benzene, toluene, xylene or a suitable mixture of aliphatic and aromatic hydrocarbons.
Since any trace of moisture affect the cyclic amide polymerization, it is recommended that perfectly anhydrous reagent should be used or that they should be dried in any known manner before the initiation of lactam ring. In a feature of the present invention, the amount of polymerizable stabilizer varies from 1 to 25 percent, preferably from 3 to 18 percent based on the total quantity of cyclic amide monomer. The amount of catalyst is in the range from 0.005 to 1 weight percent based on the total amount of the monomer. The amount of activator employed is in the range between 0.005 and 10 mol % and preferably between 0.5 and 3 mol%. The ratio of monomer to organic continuous phase is between 5 and 50 and preferably in the range from 10 to 30. The polymerization can be carried out in any conventional resin reactor equipped with a double walled condenser, a thermowell, an inlet tube for nitrogen gas purging and an addition funnel for monomer
feeding. Stirring can be done by using twin shaft blade or turbine type stirrer or by any conventional stirring device. The agitator speed may be in between 200 and 800 revolutions per minute (rpm). The polymerization reaction can be carried out between 40°C and 300°C and more preferably between 80°C and 190°C. The reaction time is typically between 3 and 10 hours. The conversion of cyclic amide to poly(amide)s is in the range between 82 and 100 percent. The poly(amide) particles formed at the end of the reaction is washed thoroughly with a low boiling aliphatic hydrocarbon particularly hexane followed by acetone and dried at 90 deg C under vacuum. The particle size of the poly(amide) particles ranges from 0.75 to 500 µ, depending on the concentration of the stabilizer.
In yet another feature of the present invention the amphiphilic block copolymer is prepared via sequential anionic polymerization technique having poly(isoprene) as hydrophobic repeating unit with a number average molecular weight preferably 1000 to 50000 and more preferably between 2000 and 15000 and having a block of hydrophilic poly(ethylene oxide) repeating unit with a number average molecular weight preferably 200 to 20000 and more preferably between 1000 and 5000.
The present invention is further exemplified by the following examples that are set forth for illustration only and should not be construed to limit the scope of the application in any manner.
Comparative Example 1
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The polymer obtained was in the form of lumps.
Comparative Example 2
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of lauryl lactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The polymer obtained was in the form of lumps.
Comparative Example 3
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged O.lg of stearic acid, 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that
temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The yield of free flowing particles was 15% and the remaining polymer was in the form of lumps.
Comparative Example 4
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.1 g of N- stearyl caprolactam, 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours. The yield of free flowing particles was 28% and the remaining polymer was in the form of lumps.
Comparative Example 5
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.1 g of carboxyl terminated (polylaurylmethacrylate) (Mn -5000), 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents
were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours. The yield of free flowing particles was 10% and the remaining polymer was in the form of lumps.
The comparative examples illustrate that particle stabilizer with suitably disposed amphiphilic character and/or a long hydrophobic segment with reactive functionality is essential for producing poly(amide)s in spherical form.
Example 1
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.04 g of N- poly (laurylmethacrylate) caprolactam (Mn -1000), 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted e-caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 2
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.06 g of N- poly (laurylmethacrylate) caprolactam (Mn -1000), 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted e-caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 3
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.1 g of N- poly (laurylmethacrylate) caprolactam (Mn -1000), 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone
to remove any unreacted e-caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 4
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.04 g of N- poly (laurylmethacrylate) caprolactam (Mn -2000), 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted e-caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 5
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.06 g of N- poly (laurylmethacrylate) caprolactam (Mn -2000), 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide)
particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted e-caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 6
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.1 g of N- poly (laurylmethacrylate) caprolactam (Mn -2000), 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 7
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.02 g of N- poly (laurylmethacrylate) caprolactam (Mn -5000), 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature
was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted e-caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 8
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.06 g of N- poly (laurylmethacrylate) caprolactam (Mn -5000), 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted e-caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 9
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.lg of N- poly (laurylmethacrylate) caprolactam (Mn -5000), 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was
maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted e-caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 10
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged O.lg of N- poly (laurylmethacrylate) caprolactam (Mn -2000), 14 g of paraffin oil, 18.5 milligram of NaH and 2 g of lauryl lactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 45 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted lauryl lactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 11
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged O.lg of N- poly (laurylmethacrylate) caprolactam (Mn -2000), 14 g of paraffin oil, 18 milligram of NaH, 1.8 g of caprolactam and 0.2 g lauryl
lactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 34 µL was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted lactam monomer. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 12
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.lg of N- poly (laurylmethacrylate) caprolactam (Mn -2000), 14 g of paraffin oil, 20 milligram of NaH, 0.2 g of caprolactam and 1.8 g lauryl lactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 48 µL was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted lactam monomer. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 13
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.lg of N- poly (laurylmethacrylate) caprolactam (Mn
-2000), 14 g of paraffin oil, 15 milligram of NaH, 1.0 g of CL and 1.0 g lauryl lactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 28 µL was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted lactam monomer. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 14
All manipulations were performed under high vacuum and using high purity nitrogen gas. To a flame dried 250 mL single necked round bottom flask fitted with a septum adapter with N2/vaccum inlet, 100 mL pure cyclohexane was transferred by stainless steel capillary tube under N2. The initiator tert-butyllithium was added drop-wise until a persistent pale yellow color of the initiator remained. Usually 0.2 - 0.4 mL of 0.09 M initiator was required to quench the impurities for 100 mL cyclohexane. Subsequently, the calculated amount of the initiator was added using a syringe. The temperature of the flask was maintained at 30 °C using an oil bath. Isoprene 3 mL was then added to the flask through stainless steel capillary tube within 10 s. The reaction was continued for 15 minutes followed by the addition of 10 fold excess of ethylene oxide over the initiator concentration. The mixture was stirred well for 6 h and terminated with acetic acid. The polymer was precipitated in cold methanol. The polymer obtained was dried under vacuum for 8 hour. The protic impurities present were further removed by dissolving the
polymer in dry toluene, the solvent is removed under reduced pressure and stirred under vacuum for 8 h. This procedure was repeated thrice to ensure removal of all volatile protic impurities. To this purified (hydroxyl terminated poly(isoprene) prepolymer 100 ml THF was added and transferred to the reaction flask using a stainless steal capillary tube. The polymer solution was titrated with deeply rep colored trityl potassium. The titration was stopped after a slight orange color in the polymer solution persisted for 5 minutes followed by the addition of required amount of trityl potassium. Then, 2 mL of purified 20% ethylene oxide in THF was transferred using a syringe into a glass ampoule This ampoule was then attached to the reaction flask and added the ethylene oxide solution. The reaction was continued for 32 h at 60 °C. The polymerization was terminated with acetic acid. The amphiphilic block copolymer thus obtained was precipitated in methanol and dried at room temperature under vacuum for 5 h. The amphiphilic block copolymer had a number average molecular weight 12,700, weight average molecular weight 15230 and polydispersity index 1.19.
In a separate three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.1 g of poly(isoprene-b-ethyleneoxide) prepared as mentioned above, 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed
by acetone to remove any unreacted caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
Example 15
In a three neck 100 mL glass reactor, fitted with an overhead stirrer, nitrogen inlet tube and guard tube, was charged 0.1 g of poly(butadiene-b-ethyleneoxide) having Mw = 4000, Mn = 3389 and Mw/Mn = 1.18, 14 g of paraffin oil, 15.5 milligram of NaH and 2 g of caprolactam. The contents were heated to 80° C and kept at that temperature for one hour while stirring was maintained at 800 rpm. Phenyl isocyanate, 30 microliter was added and the temperature was quickly increased to 160°C. The reaction was continued for 5 hours. The poly(amide) particles obtained were washed with hexane to remove paraffin oil followed by acetone to remove any unreacted caprolactam. The poly(amide) was dried in vacuum oven at 80°C for 5 hours.
The properties of the poly(amide) particles obtained from the aforementioned examples (1-15) are given in the following table. Yield was calculated gravimetrically after washing the poly(amide) particles thoroughly with hexane followed by acetone. Viscosity was determined for 0.5% solution in m-cresol at 25 deg C. Thermal properties were recorded using a Perkin Elmer DSC7 thermal analyzer. Particle size was measured using Olympus BX50 optical microscope. Approximately 100 particles were chosen and the average particle size is given in the Table 1.
Table 1: Properties of poly (amide) particles

(Table Removed)
(a) Greater than 95 % of the particles had the specified size.






We claim :
1. A process for preparation of poly(amide) which comprises polymerizing
lactams with anionic initiator and, optionally, an activator and in the presence
of a polymerizable or polymeric steric stabilizer in an organic solvent and
heating the reaction mixture between 70°C and 270°C with stirring from 200
to 800 rpm for a period ranging between 30 minutes and 8 hours and
separating the sphereical particles of poly(amide)s by conventional
procedures.
2. A process as defined in claim 1 wherein lactam used contains 4 to 12 carbon
atoms in the ring and may or may not contain other functional groups, which
are exemplified by pyrrolidones, C-alkylated pyrrolidones, piperidine,
butanolactam, pentanolactam, hexanolactam, dodecyllactam.
3. A process as defined in claims 1 and 2 wherein the anionic initator used are
alkali metals alkali metal hydrides, alcoholates, carbonates, alkali metals salts
of diverse weak acids, alkali aluminiums, alkali aluminium hydride and their
partial or total alkoxides or lactam salts grignard reagents, quaternary
ammonium salts of lactams or of their organic compounds and guanidium
salts of lactams.
4. A process as defined in claims 1 to 3 wherein the activator used are the
strongest alkylating agent for lactam olymerization are exemplified by N-acyl
lactams (N-acetyl lactam, N-benzoyl lactams, carbonyl-N-bis lactams),
compounds containing an electroegatively N-substituted amide groups such as
N-cyano lactam, lactam-N-carboxylate esters, compounds containing an imide group, organic or inorganic compounds such as esters, acids halides, anhydrides and isocyanates or diisocyanates capable of forming N-substituted lactam derivatives by reacting with monomer lactam or its alkaline salt. 5. A process as defined in claims 1 to 4 wherein the polymerizable stabilizer is a polycondensable macromonomer, particularly a macromonomer containing a long chain hydrophobic moiety with a lactam ring at the chain terminal, as mentioned in formula (I)
(Formula Removed)
Wherein
R=an alkyl group with 1 -40 carbon atoms
R1=hydrogen or methyl
R2- alkylene units with 1 -5 carbon atoms
X= bifunctional moiety derived from mercaptoacetic acid, 3-mercaptopropionic acid,
mercaptosuccinic acid.
n=3-45
m=> 2 methylene units attached to the hetero atoms
6. A process as defined in 1 to 6 wherein the polymeric stabilizer is a block
copolymer which are exemplified by poly (isoprene), poly(butadiene) or their
hydrogenated analogues, poly (dimethysiloxane) with a number average
molecular weight preferably 1000 to 500000 and more preferably between
2000 and 15000 and having a single block of hydropolic repeating unit with a
number average colecular weight preferably 200 to 20000 and more
preferably between 1000 and 5000 the hydrophilic blocks are exemplified by
poly (alkylene oxide) like poly (eithylene oxide), poly (propylene oxide) and
poly (tetramethylene oxide).
7. A process as defined in claims 1 to 5 wherein the organic solvent used are non
reactive and good solvent for the monomers and non-solvent for the polymer
particles, which are exemplified by aliphatic hydrocarbons selected from
hexane, heptane octane, decane, isooctane, dodecane, hexadecane, superior
kerosene, paraffin oil, white mineral oil, and aromatic hydrocarbons selected
from benzene, tonuene, xylene and mixtures thereof.
8. A process for preparation of poly(amide) particles substantially as herein
described with reference to the examples.

Documents:

961-del-2000-abstract.pdf

961-del-2000-claims.pdf

961-del-2000-correspondence-others.pdf

961-del-2000-correspondence-po.pdf

961-del-2000-description (complete).pdf

961-del-2000-form-1.pdf

961-del-2000-form-19.pdf

961-del-2000-form-2.pdf


Patent Number 242141
Indian Patent Application Number 961/DEL/2000
PG Journal Number 34/2010
Publication Date 20-Aug-2010
Grant Date 16-Aug-2010
Date of Filing 01-Nov-2000
Name of Patentee COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH
Applicant Address RAFI MARG, NEW DELHI-110001, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 LAGUDI SRINIVASAN RAMANATHAN NATIONAL CHEMICAL LABORATORY, PUNE, MAHARASHTRA, INDIA.
2 SWAMINATHAN SIVARAM NATIONAL CHEMICAL LABORATORY, PUNE, MAHARASHTRA, INDIA.
PCT International Classification Number NA
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA