CN115215758B - Preparation method of active group end-capped polyamide oligomer - Google Patents
Preparation method of active group end-capped polyamide oligomer Download PDFInfo
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- C07—ORGANIC CHEMISTRY
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- C07C231/00—Preparation of carboxylic acid amides
- C07C231/10—Preparation of carboxylic acid amides from compounds not provided for in groups C07C231/02 - C07C231/08
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
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- C07C231/02—Preparation of carboxylic acid amides from carboxylic acids or from esters, anhydrides, or halides thereof by reaction with ammonia or amines
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- 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
- C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
- C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
- C08G69/08—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from amino-carboxylic acids
- C08G69/14—Lactams
- C08G69/16—Preparatory processes
- C08G69/18—Anionic polymerisation
- C08G69/20—Anionic polymerisation characterised by the catalysts used
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- C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
- C08G69/46—Post-polymerisation treatment
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Abstract
The invention provides a preparation method of active group end-capped polyamide oligomer, which takes lactam as a main raw material, takes deionized water, linear amino acid or active group end-capped polyamide oligomer with polymerization degree less than or equal to 3 as a catalyst for catalyzing ring opening of the lactam, and controls the molecular weight of the obtained active group end-capped polyamide oligomer by controlling the appropriate temperature and time of the preliminary polymerization reaction of the lactam, and introducing a ring opening protective agent and a molecular weight regulator into a system at specific time to regulate the total polymerization reaction time and the like. The preparation method can prepare the end carboxyl or end amino terminated polyamide oligomer with high end capping purity and polymerization degree of 2-20.
Description
Technical Field
The invention belongs to the technical field of organic synthesis and high molecular polymerization, and in particular relates to a preparation method of a polyamide oligomer blocked by active groups.
Background
Along with the increasing pursuit of people on high-quality fabrics of sports and leisure clothes, such as comfort, environmental protection, health, safety and the like, nylon textiles with comfort are increasingly popular with a lot of consumers, common nylon fabrics are difficult to produce in a mass production mode, and performances such as moisture absorption, quick drying, softness, fluorescence safety display and the like are expected to be endowed to nylon fabrics, so that functional finishing is required to be carried out on the common nylon fabrics by using chemical auxiliary agents. However, due to the influence of high cohesive energy of hydrogen bonds of amide groups in a nylon molecular structure, chemical functional additives are difficult to adsorb, and the use of a cross-linking agent can cause the problems of poor color fastness, poor hand feeling and the like. The reactive group such as carboxyl or amido end capped polyamide oligomer can be polymerized with other functional monomers to prepare anchoring functional auxiliary agents for chinlon by utilizing the reactivity of carboxyl/amido end capped polyamide oligomer, so that the individual requirements of performances such as durability, comfort, moisture absorption, quick drying, softness, fluorescence safety display and the like are met.
The linear amino acid is adopted as a main raw material in a laboratory to react with adipic acid or hexamethylenediamine to prepare the polyamide oligomer with the end capped by the active group and smaller in polymerization degree, however, the linear amino acid is adopted as the raw material, so that the cost is high, and the large-scale production is not suitable.
At present, caprolactam is used as a main raw material, a process for preparing polyamide oligomer (the polymerization degree is 2-20 repeating units relative to nylon high polymer) by ring-opening polymerization of caprolactam is rarely reported, and the molecular weight control and preparation of the polyamide oligomer terminated by active groups are not reported. The end-capping purity of the polyamide oligomer capped by active groups has a great influence on the function of the polyamide oligomer serving as an anchoring functional auxiliary agent. How to prepare the active terminated polyamide oligomer with the polymerization degree of 2-20 and high terminated purity of carboxyl or amine terminal groups, which is used as an anchoring functional auxiliary agent, is a technical problem to be solved at present.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a preparation method of an active group end-capped polyamide oligomer, and aims to solve the technical problems that the prior art lacks a preparation method of an active group end-capped polyamide oligomer which has the polymerization degree of 2-20, and high end carboxyl or end amino end capping purity, and the like, and is prepared with low cost and high efficiency.
In order to achieve the above purpose, the present invention provides a preparation method of a polyamide oligomer terminated by active groups, wherein the active groups are carboxyl groups or amine groups, and the preparation method comprises the following steps:
(1) Taking the lactam as a main raw material, taking one or more of deionized water, linear amino acid and active group terminated polyamide oligomer with polymerization degree less than or equal to 3 as a catalyst, heating to melt the raw material, uniformly stirring, and heating to 210 ℃ or above to cause the lactam to undergo preliminary ring-opening polymerization for 0.5-2 hours;
(2) Heating to 230 ℃ and above, and when the pressure reaches 0.3MPa and above, dropwise adding a ring-opening protective agent and a molecular weight regulator into the reaction system, controlling the temperature to 230-250 ℃ and the pressure to 0.3-0.6 MPa in the dropwise adding process, and capping the polyamide obtained by preliminary ring-opening polymerization in the step (1) and controlling the molecular weight of the obtained polyamide;
(3) And (3) after the reaction is finished, releasing pressure, cooling and removing unreacted raw materials and byproducts generated in the reaction process to obtain the polyamide oligomer capped by the active groups.
Preferably, the linear amino acid is one or more of omega-aminobutyric acid, omega-aminopentanoic acid, omega-aminocaproic acid, omega-aminoheptanoic acid, omega-aminocaprylic acid and omega-aminononanoic acid.
Preferably, the polymerization degree of the polyamide oligomer terminated by active groups is 2-20, the molar ratio of the lactam to the molecular weight regulator is 20:1-2:1, and the catalyst dosage is less than or equal to 1wt% of the lactam dosage; the mass of the ring-opening protective agent is 1-2 times of that of the lactam.
Preferably, the reaction temperature of the preliminary ring-opening polymerization reaction in the step (1) is 210-230 ℃ and the pressure is 0.3-0.6 Mpa.
Preferably, when the reactive group of the reactive group-terminated polyamide oligomer is carboxyl, controlling the dropping speed in the step (2) to ensure that the ratio of the acid value to the amino value of the polyamide oligomer is more than or equal to 15; when the active group of the active group terminated polyamide oligomer is an amino group, controlling the dropping speed in the step (2) to enable the ratio of the amino group value to the acid value of the polyamide oligomer to be more than or equal to 15.
Preferably, the polymerization degree of the polyamide oligomer is 2-20, each mole of lactam participates in the reaction, and the corresponding added molecular weight regulator and ring-opening protective agent are added dropwise within 2-4 hours, so that the end capping ratio of the obtained polyamide oligomer is more than 15.
Preferably, the cyclic lactam in the step (1) is subjected to preliminary ring opening polymerization until the reaction in the step (3) is finished, and the cyclic lactam is subjected to pressure release after lasting for 3 to 6 hours.
Preferably, the ring-opening protecting agent in the step (3) is a nitrogen-containing high-melting-point inert solvent, and the melting point of the nitrogen-containing high-melting-point inert solvent is greater than or equal to 200 ℃; further preferred are one or more of 1, 3-dimethyl-2-imidazolidinone, 1, 3-dimethyl-3, 4,5, 6-tetrahydro-2-pyrimidinone and N-methylpyrrolidone.
Preferably, the molecular weight regulator is dicarboxylic acid HOOC-R 1 -COOH or diamine H 2 N-R 2 -NH 2 The dicarboxylic acid is aliphatic dicarboxylic acid with 2-15 carbon atoms, alicyclic dicarboxylic acid with 2-15 carbon atoms or aromatic dicarboxylic acid with 8-20 carbon atoms; the diamine is aliphatic diamine with 2-10 carbon atoms, alicyclic diamine with 5-20 carbon atoms, aromatic diamine with 6-20 carbon atoms, polyether amine with 150-2003 molecular weight or alkali metal salt of 4,4 '-diaminostilbene-2, 2' -disulfonic acid.
Preferably, the preliminary ring-opening polymerization reaction in the step (1) is carried out in a polymerization kettle, the polymerization kettle is connected with a high-level tank through a communicating vessel, and the ring-opening protective agent and the molecular weight regulator are put into the high-level tank; before the preliminary polymerization reaction, the polymerization kettle and the elevated tank are vacuumized, then are replaced by inert gas, and then maintain positive pressure, so that the influence of air in the polymerization reaction is avoided, and the reaction system is conveniently dripped with a ring-opening protective agent and a molecular weight regulator in the step (2) through the connection of a communicating vessel.
In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:
(1) The invention provides a preparation method of polyamide oligomer blocked by active groups, which adopts lactam as a main raw material, adopts deionized water, linear amino acid or polyamide oligomer blocked by active groups with polymerization degree less than or equal to 3 as a catalyst for catalyzing caprolactam ring opening, and controls the polymerization degree and the blocking purity of the obtained polyamide oligomer blocked by active groups by controlling the proper temperature and time during the preliminary polymerization of lactam monomers, introducing a ring opening protective agent and a molecular weight regulator into a system at specific time, regulating the total polymerization time and the like.
(2) When the polyamide oligomer is prepared in the preferred embodiment of the invention, the single conversion rate of the cyclic lactam is more than 95%, and the prepared polyamide oligomer with the end capped by active groups can effectively control the molecular weight and the distribution according to the application performance requirement of an anchoring function; the ratio of the acid value to the amino value of the polyamide oligomer blocked by the carboxyl groups of the active groups is more than 15, the ratio of the amino value to the acid value of the polyamide oligomer blocked by the amino groups is more than 15, the maximum can be close to 50, and the blocking purity is higher.
(3) The conversion rate, namely the ring opening rate, of the cyclic lactam of the polyamide oligomer with the end capped by the active group, which is prepared by the method, can reach more than 97%, and the purity of the polyamide oligomer with the end capped by the active group, which is prepared by the method, can be further improved by carrying out gas stripping purification on a product obtained by the reaction in the preferred embodiment, and can reach 99% in the preferred embodiment.
Drawings
FIG. 1 is a schematic illustration of the preparation flow of reactive group terminated polyamide oligomers of the present invention;
FIG. 2 is a schematic diagram of an apparatus for preparing reactive group terminated polyamide oligomers according to the present invention;
FIG. 3 is a mass spectrum of the polyamide oligomer prepared in example 1;
FIG. 4 is a mass spectrum of the polyamide oligomer prepared in example 2;
FIG. 5 is a mass spectrum of a polyamide oligomer prepared in comparative example 1;
FIG. 6 is a mass spectrum of a polyamide oligomer prepared in comparative example 2;
FIG. 7 is a mass spectrum of a polyamide oligomer prepared in comparative example 3.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The carboxyl/amine terminated polyamide oligomer is used as an active anchoring functional unit, and the unit is used for manufacturing chemicals for nylon functions such as moisture absorption, quick drying, softness, fluorescent marks, antibiosis and the like through block polymerization, and the materials for nylon with the modified functions have firm anchoring effects. However, the preparation process of caprolactam ring-opening polymer, i.e. oligomer (polymerization degree is 2-20 repeating units, compared with nylon high polymer) and unreacted caprolactam treatment are reported recently, and the method of hot water soaking and the like in nylon manufacturing process is not suitable, and the solvent in chemical extraction method is easy to cause secondary pollution. Meanwhile, the polymerization degree control and the end-capping purity process technology of the end-carboxyl/amino end-capped polyamide oligomer are not reported.
The polyamide oligomer terminated by the active group is carboxyl-terminated or amino-terminated polyamide PAn, wherein the polymerization degree is 2-20 repeated units, and the polyamide oligomer can be regarded as nylon with small polymerization degree. The amide group in the molecule can form a hydrogen bond with amide in a chinlon macromolecular chain to achieve the so-called anchoring, and the structural formula is as follows: wherein n is more than or equal to 2 and less than 20.
The invention provides a preparation method of a polyamide oligomer blocked by active groups, which is shown in figure 1 and specifically comprises the following steps:
(1) Taking the cyclic lactam as a main raw material, taking one or more of deionized water, linear amino acid and active group terminated polyamide oligomer with the polymerization degree less than or equal to 3 as a catalyst, heating to melt the raw material, uniformly stirring, and heating to 210 ℃ or above to cause the cyclic lactam to undergo preliminary ring-opening polymerization for 0.5-2 hours, preferably 0.8-1.5 hours; taking caprolactam as an example, the caprolactam undergoes ring-opening polymerization as follows:
(2) Heating to 230 ℃ and above, and when the pressure reaches 0.3MPa and above, dropwise adding a ring-opening protective agent and a molecular weight regulator into the reaction system, controlling the temperature to 230-250 ℃ and the pressure to 0.3-0.6 MPa in the dropwise adding process, and capping the obtained polyamide and controlling the molecular weight of the obtained polyamide oligomer; the reactions that occur are:
carboxyl-terminated polyamide oligomer PA (n):
amine-terminated polyamide oligomer PA (n):
(3) And after the reaction is finished, releasing pressure, and cooling to remove unreacted raw materials (including deionized water, ring-opening protective agent, unreacted lactam and the like) and byproducts generated in the reaction process to obtain the polyamide oligomer capped by the active groups.
The cyclic lactam of the present invention is a cyclic lactam, preferably a 4-to 7-membered ring cyclic lactam, including but not limited to caprolactam, valerolactam, butyrolactam, etc.
In some embodiments, the feedstock of step (1) further comprises other additives, including color protectants. The color protecting agent is selected from one or more of nylon antioxidants such as SEED, N' -bis (4-amino-2, 6-tetramethyl piperidinyl) -1, 3-benzene dicarboxamide, 1010, 1076, phosphorous acid and triphenyl phosphite, and the dosage of the color protecting agent is less than or equal to 3.0% of the feeding quality of the cyclic lactam.
The polyamide oligomer terminated by active groups prepared by the method takes a cyclic lactam monomer as a main raw material, and takes deionized water, linear amino acid or a mixture of one or more of polyamide oligomers with polymerization degree less than or equal to 3 as a catalyst. The linear amino acids of the invention can be expressed as HOOC-R 1 -NH2, including in particular but not limited to omega-aminobutyric acid, omega-aminopentanoic acid, omega-aminocaproic acid, omega-aminoheptanoic acid, omega-aminocaprylic acid, omega-aminononanoic acid or a polymeric polyamide oligomer having a degree of polymerization of 3 or less; the R is 1 Is a substituted or unsubstituted aliphatic, alicyclic or aromatic hydrocarbon group having 1 to 15 carbon atoms, and the linear amino acid is preferably ω -aminopentanoic acid or ω -aminocaproic acid. In a preferred embodiment, the linear amino acid is one or more of omega-aminobutyric acid, omega-aminopentanoic acid, omega-aminocaproic acid, omega-aminoheptanoic acid, omega-aminocaprylic acid and omega-aminononanoic acid.
In some embodiments, the molar ratio of the cyclic lactam to the molecular weight regulator is 20:1 to 2:1, and the molecular weight regulator is theoretically fully reacted, and the average polymerization degree is 2 to 20; the catalyst is used in an amount of less than 1wt% of the amount of the cyclic lactam; the mass of the ring-opening protective agent is 1-2 times of that of the lactam.
In some embodiments, the preliminary ring-opening polymerization reaction in step (1) has a reaction temperature of 210℃to 230℃and a pressure of 0.3 to 0.6MPa. The degree and time of the preliminary ring-opening polymerization directly determine the polymerization degree of the prepared polyamide oligomer.
In some embodiments, as shown in fig. 2, the preliminary ring-opening polymerization reaction in step (1) is performed in a polymerization kettle 2-1, a solid feed port 2-3 is further provided at the top of the polymerization kettle 2-1, the polymerization 2-1 is connected with a head tank 2-2 through a communicating vessel, and the ring-opening protecting agent and the molecular weight regulator are fed into the head tank 2-2; before the preliminary ring-opening polymerization reaction, the polymerization kettle and the elevated tank are vacuumized, then are replaced by inert gas, and then maintain positive pressure, so that the influence of air in the polymerization reaction is avoided, and the reaction system is conveniently dripped with a ring-opening protective agent and a molecular weight regulator in the step (2) through the connection of a communicating vessel.
And (2) simultaneously dropwise adding the ring-opening protective agent and the molecular weight regulator, wherein the dropwise adding of the ring-opening protective agent and the molecular weight regulator is used for blocking the polyamide obtained by preliminary ring-opening polymerization, and controlling the molecular weight of the obtained polyamide oligomer. Experiments show that the molar ratio of the cyclic lactam to the molecular weight regulator determines the degree of polymerization (average molecular weight) in the oligomer, the initial ring-opening polymerization end point also determines the molecular weight distribution range, and the dripping time (dripping acceleration) of the ring-opening protecting agent and the molecular weight regulator is also related to the molecular weight distribution of the oligomer. And experiments show that the dripping speed of the ring-opening protective agent and the molecular weight regulator has a certain influence on the end-capping purity of the active group end-capped polyamide oligomer. "end-capping purity" refers to the purity of the end-capped polyamide oligomer of the subject end-capping reactive group, such as the higher the ratio of acid value to amine value of the carboxyl-capped polyamide oligomer at the time of end-capping of the reactive group, the greater the end-capping purity of the reactive group-capped polyamide oligomer. In some embodiments, when the reactive group of the reactive group-terminated polyamide oligomer is carboxyl, controlling the dropping speed in the step (2) to make the ratio of the acid value to the amine value of the polyamide oligomer not less than 15; when the active group of the active group terminated polyamide oligomer is an amino group, controlling the dropping speed in the step (2) to ensure that the ratio of the amino group value to the acid value of the polyamide oligomer is not less than 15. In a preferred embodiment, in order to prepare the polyamide oligomer with the polymerization degree in the range of 2-20, each mole of the lactam participates in the reaction, the corresponding molecular weight regulator and the ring-opening protecting agent are added dropwise within 2-4 hours, preferably within 2.5-3.5 hours, and the end capping ratio of the obtained polyamide oligomer is more than 15.
In some embodiments, from the initiation of the preliminary ring-opening polymerization of the cyclic lactam in step (1) to the end of the reaction in step (3), the reaction lasts for 3 to 6 hours, preferably 3 to 4 hours, and then the pressure is relieved, so as to obtain the polyamide oligomer terminated by the active group with the polymerization degree of 2 to 20.
In some embodiments, the ring-opening protecting agent in step (2) is a nitrogen-containing high-melting inert solvent having a melting point of 200 ℃ and above, which on the one hand acts as a good solvent for dissolving the cyclic lactam; on the other hand, based on the similar principle of miscibility, the molecular weight of the polyamide in the ring-opening polymerization process of the lactam can be protected from being excessively fast increased. Preferred ring opening protecting agents are 1, 3-dimethyl-2-imidazolidinone (abbreviated as DMI), 1, 3-dimethyl-3, 4,5, 6-tetrahydro-2-pyrimidinone (abbreviated as DMPU), N-methylpyrrolidone, and the like.
In some embodiments, the molecular weight regulator is a dicarboxylic acid HOOC-R 1 -COOH or diamine H 2 N-R 2 -NH 2 The dicarboxylic acid is an aliphatic dicarboxylic acid having 2 to 15 carbon atoms (such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, etc.), an aromatic dicarboxylic acid having 8 to 20 carbon atoms (such as phthalic acid, terephthalic acid, 2, 6-or 2, 7-naphthalene dicarboxylic acid, 4' -stilbenedicarboxylic acid, 2, 5-thiophene dicarboxylic acid, diphenoxyethane dicarboxylic acid, tolylene dicarboxylic acid, xylylene dicarboxylic acid, and alkali metal salts of 5-sulfoisophthalic acid, etc.). Preferably one or more of glutaric acid and adipic acid. The diamine is aliphatic diamine with 2-10 carbon atoms (such as ethylenediamine, propylenediamine, hexamethylenediamine, decylenediamine, etc.), alicyclic diamine with 5-20 carbon atoms (such as 1, 3-or 1, 4-cyclohexanediamine, isophoronediamine)4,4' -diaminocyclohexylmethane, 2-bis (4-aminocyclohexyl) propane, etc.), aromatic diamines having 6 to 20 carbon atoms (p-phenylenediamine, 2, 4-or 2, 6-toluenediamine, etc.), polyetheramines of different molecular weight series (ED 150, ED230, ED400/ED600, ED900, ED 2003), alkali metal salts of 4,4' -diaminostilbene-2, 2' -disulfonic acid, etc. Preferably one or more of pentylene diamine, hexylene diamine, low molecular weight polyetheramines.
The preparation method prepares the polyamide oligomer capped by active groups, wherein the active groups are carboxyl groups or amino groups, and cyclic lactam is used as a main raw material, so that the active capped polyamide oligomer with high purity of carboxyl end groups or amino end groups is obtained, the application requirement of anchoring functional chemicals is met, the ring opening rate (conversion rate) of the lactam is improved, deionized water or a proper amount of linear amino acid or the polyamide oligomer capped by the active groups with the polymerization degree of less than or equal to 3 is added into a polymerization kettle to be used as a catalyst in a preferred scheme, the reaction efficiency is improved, the deionized reaction activity is lower than that of the linear amino acid, the commercial cost of the linear amino acid is higher, and the combination of the deionized water and the polyamide oligomer capped by the active groups with the polymerization degree of less than or equal to 3 is preferred as the ring opening catalyst. In some embodiments, the method of preparing a carboxyl-terminated polyamide oligomer having a degree of polymerization of less than or equal to 3 comprises the steps of: the main raw material is lactam, adipic acid or glutaric acid is end-capping agent, the mole ratio of the lactam to the adipic acid (2-3): 1, deionized water is catalyst to polymerize. Amine-terminated polyamide oligomers having a degree of polymerization of less than or equal to 3, preferably carboxyl-terminated polyamide oligomers having a degree of polymerization of less than or equal to 3, may also be used. When the catalyst is used, the ratio of the acid value to the amino group of the polyamide oligomer terminated by the active group carboxyl is not required to be very high and is more than or equal to 1.
When preparing active group carboxyl end-capped polyamide oligomer, the prepared polyamide oligomer not only requires the polymerization degree to be in the required range, but also has the better ratio of the acid value to the amine value. The same applies to the preparation of amine-terminated polyamide oligomers. In reality, the combination of chemicals and nylon fiber surface interfaces is applied, and the combination fastness is expressed in three aspects: the forces, bond density and degree of crosslinking, intermolecular forces are four: covalent bonds, ionic bonds, hydrogen bonds, van der Waals forces. The chemical and nylon fiber are combined by covalent bond and ionic bond at high cost, so that only hydrogen bond and Van der Waals force bonding are involved, and the acting force of the hydrogen bond is 1-2 orders of magnitude of Van der Waals force. Therefore, through the discovery of an 'anchoring' technology of an amide oligomer intermediate, the amide oligomer can be understood as a key part for solving the problem of poor durability of chemicals for chinlon, the terminal active key part is easy to block and connect with an amino terminal or acid group terminal functional monomer, the terminal active key part is prevented from polymerizing carboxyl and amino, the functional chemicals are synthesized through the 'anchoring' of strong hydrogen bonds of the amide oligomer amide, and the application problem of the combination durability of chinlon materials and functional chemicals is solved.
The following are examples:
example 1
1.0mol of caprolactam, 6.0g of deionized water, 0.6g of N, N' -bis (4-amino-2, 6-tetramethylpiperidinyl) -1, 3-benzenedicarboxamide and 0.8g of triphenyl phosphite are put into a polymerization kettle, and the reaction kettle is closed; 230g of ring-opening protective agent DMI and 0.5mol of adipic acid of molecular weight regulator are put into a high-level tank connected with a polymerization kettle; and (3) vacuumizing and replacing with nitrogen, communicating the polymerization kettle with a high-level tank gas phase balance pipe, closing a dropwise adding valve, and pressurizing the nitrogen of the system by 0.2MPa. Heating the polymerization kettle, melting at 110 ℃, starting polymerization stirring, keeping the temperature at 110 ℃ for half an hour, continuously heating, keeping the temperature at 230 ℃ within 1 hour, keeping the pressure of the polymerization kettle at 0.45MPa, keeping the temperature for 1 hour (preliminary ring-opening polymerization), starting to drop a ring-opening protective agent DMI and a molecular weight regulator in a high-level tank, dropwise adding for 3 hours, controlling the temperature to 248 ℃, controlling the pressure to 0.5MPa, dropwise adding for 3 hours, starting to release pressure after 4 hours, keeping the temperature at 250 ℃, and starting to cool and desolventize the pressure for 45 minutes and recycling unreacted caprolactam, wherein the generated carboxyl-terminated polyamide oligomer is formed or cut into particles by cooling a steel belt at 150 ℃.
The resulting carboxyl-terminated polyamide oligomer was examined and the results were as follows: acid value 5.37mmol/g; amine group value 0.32mmol/g; the ratio of acid value to amine value is 16.8, the caprolactam conversion rate is 95.01%, the mass spectrum (negative ion mode) of the liquid chromatograph-mass spectrometer (Agilent 1260 II-6130) is shown in figure 3, the maximum molecular weight 452 (Mn=113n+146), the maximum polymerization degree n is 2.7, and the integral calculation average polymerization degree n is 2.05.
Example 2
Into a polymerization vessel, 1mol of 113.0g of caprolactam, 3.0g of deionized water, 18.6g of the product of example 1, 0.6g of N, N' -bis (4-amino-2, 6-tetramethylpiperidinyl) -1, 3-benzenedicarboxamide and 0.8g of triphenyl phosphite were charged and the reaction vessel was closed; 230g of ring-opening protective agent DMI and 0.251mol of molecular weight regulator adipic acid, namely 36.5g, are put into a high-level tank connected with a polymerization kettle; and (3) vacuumizing and replacing with nitrogen, communicating the polymerization kettle with a high-level tank gas phase balance pipe, closing a dropwise adding valve, and pressurizing the nitrogen of the system by 0.2MPa. Heating a polymerization kettle, melting at 110 ℃, starting polymerization stirring, keeping the temperature at 110 ℃ for half an hour, continuously heating, keeping the temperature at 230 ℃ within 1 hour, keeping the pressure of the polymerization kettle at 0.45MPa, keeping the temperature for 1 hour (1 hour of preliminary ring-opening polymerization), starting to drop a ring-opening protective agent DMI and a molecular weight regulator in a high-level tank, dropwise adding for 3 hours, controlling the temperature to be about 248 ℃, controlling the pressure to be 0.5MPa, dropwise adding for 3 hours, starting to release pressure after polymerization reaction is carried out for 4 hours (1 hour+3 hours of preliminary polymerization), keeping the temperature at about 250 ℃, reducing the temperature for 45 minutes, removing solvent and recycling unreacted caprolactam for standby, and cooling and granulating a generated carboxyl-terminated polyamide oligomer at 150 ℃ by a steel belt.
The resulting carboxyl-terminated polyamide oligomer was examined and the results were as follows: acid value 3.40mmol/g; amine group value 0.07mmol/g; the ratio of acid value to amino value is 48, and the caprolactam conversion rate is 97.7%. The mass spectrum (negative ion mode) of the liquid chromatograph-mass spectrometer (Agilent 1260 II-6130) is shown in fig. 4, the maximum molecular weight 587 (Mn=113n+146), the maximum polymerization degree n is 6.3, and the integral calculation average polymerization degree n is 3.9.
Example 3
1mol of 113g of caprolactam, 5.85g of omega-aminopentanoic acid and 5g of deionized water are put into a polymerization kettle, and the reaction kettle is closed after 0.5g of antioxidant 1010 and 0.3g of 1076; 230g of ring-opening protective agent N-methyl pyrrolidone and 0.1mol of molecular weight regulator hexamethylenediamine, namely 11.6g, are put into a high-order tank connected with a polymerization kettle; and (3) vacuumizing and replacing with nitrogen, communicating the polymerization kettle with a high-level tank gas phase balance pipe, closing a dropwise adding valve, and pressurizing the nitrogen of the system by 0.2MPa. Heating the polymerization kettle, melting at 110 ℃, starting polymerization stirring, keeping the temperature at 110 ℃ for half an hour, continuously starting heating, keeping the temperature at 230 ℃ within 1 hour, keeping the pressure of the polymerization kettle at 0.45MPa, keeping the temperature for 1 hour (1 hour of preliminary polymerization), starting dripping the ring-opening protectant N-methylpyrrolidone and the molecular weight regulator in the elevated tank, dripping for 3 hours, controlling the temperature to 248 ℃ or so, controlling the pressure to 0.5MPa, dripping for 3 hours, starting pressure relief after 4 hours (1 hour of preliminary polymerization and 3 hours of dripping), keeping the temperature at 250 ℃, reducing the temperature for 45 minutes, desolventizing and recycling unreacted caprolactam, and cooling the produced amine-terminated polyamide oligomer at 150 ℃ for molding a steel belt.
The generated amine terminated polyamide oligomer is detected, and the result is as follows: an amine group value of 1.62mmol/g; acid value 0.05mmol/g; the ratio of amine end group value to acid value is 32, and the caprolactam conversion rate is 96.2%.
Example 4
1mol of 113g of caprolactam, 5.85g of omega-aminopentanoic acid and 5g of deionized water are put into a polymerization kettle, and the reaction kettle is closed after 0.5g of antioxidant 1010 and 0.3g of 1076; 230g of ring-opening protective agent N-methyl pyrrolidone and 40g of ED400 polyether amine with the molecular weight of 0.1mol which are connected with a high-level tank of a polymerization kettle are put in; and (3) vacuumizing and replacing with nitrogen, communicating the polymerization kettle with a high-level tank gas phase balance pipe, closing a dropwise adding valve, and pressurizing the nitrogen of the system by 0.2MPa. Heating the polymerization kettle, melting at 110 ℃, starting polymerization stirring, keeping the temperature at 110 ℃ for half an hour, continuously starting heating, keeping the temperature at 230 ℃ within 1 hour, keeping the pressure of the polymerization kettle at 0.45MPa, keeping the temperature for 1 hour (1 hour of preliminary polymerization), starting dripping the ring-opening protectant N-methylpyrrolidone and the molecular weight regulator in the elevated tank, dripping for 3 hours, controlling the temperature to 248 ℃ or so, controlling the pressure to 0.5MPa, dripping for 3 hours, starting decompression after 4 hours (polymerization reaction in the process of 1 hour+3 hours of preliminary polymerization), keeping the temperature at 250 ℃, starting cooling and desolventizing for 45 minutes, recycling unreacted caprolactam, and cooling the produced amino-terminated polyamide oligomer at 150 ℃ for molding.
The generated amine terminated polyamide oligomer is detected, and the result is as follows: an amine group value of 1.67mmol/g; acid value 0.04mmol/g; the ratio of amine end group value to acid value is 42, and the caprolactam conversion rate is 96.8%.
Comparative example 1
Into a polymerization vessel, 1mol of 113.0g of caprolactam, 3.0g of deionized water, 18.6g of the product of example 1, 0.6g of N, N' -bis (4-amino-2, 6-tetramethylpiperidinyl) -1, 3-benzenedicarboxamide and 0.8g of triphenyl phosphite were charged and the reaction vessel was closed; 230g of ring-opening protective agent DMI and 0.251mol of molecular weight regulator adipic acid, namely 36.5g, are put into a high-level tank connected with a polymerization kettle; and (3) vacuumizing and replacing with nitrogen, communicating the polymerization kettle with a high-level tank gas phase balance pipe, closing a dropwise adding valve, and pressurizing the nitrogen of the system by 0.2MPa. Heating the polymerization kettle, melting at 110 ℃, starting polymerization stirring, keeping the temperature at 110 ℃ for half an hour, continuously heating, keeping the temperature at 230 ℃ within 1 hour, keeping the pressure of the polymerization kettle at 0.45MPa, keeping the temperature for 1 hour (initial ring-opening polymerization reaction occurs), then starting to drop a ring-opening protective agent DMI and a molecular weight regulator in a high-level tank, dropwise adding for 1 hour, controlling the temperature to be about 248 ℃, controlling the pressure to be 0.5MPa, dropwise adding for 1 hour, starting to release pressure after 2 hours, keeping the temperature at about 250 ℃, reducing the temperature for 45 minutes, removing solvent and recycling unreacted caprolactam, and cooling and granulating the generated carboxyl-terminated polyamide oligomer at 150 ℃ for molding.
The only difference between this comparative example and example 2 is that the dropping time was shortened from 3 hours to 1 hour when the same mass of the ring-opening protecting agent and the molecular weight modifier were added dropwise. The resulting carboxyl-terminated polyamide oligomer was examined and the results were as follows: acid value 3.96mmol/g; an amine group value of 1.0mmol/g; the ratio of acid value to amino value is 4, and the caprolactam conversion rate is 90.5%. The mass spectrum (negative ion mode) of the liquid chromatograph-mass spectrometer (Agilent 1260 II-6130) is shown in fig. 5, the maximum molecular weight 732 (Mn=113n+146), the maximum polymerization degree n is 5.2, and the integral calculation average polymerization degree n is 3.2.
The lower ratio of acid value to amine value indicates that too fast a dropping speed of the ring-opening protecting agent and the molecular weight regulator is unfavorable for obtaining the active terminated polyamide oligomer with higher purity of carboxyl end group or amine end group.
Comparative example 2
1.0mol of caprolactam, 6.0g of deionized water, 0.6g of N, N' -bis (4-amino-2, 6-tetramethylpiperidinyl) -1, 3-benzenedicarboxamide and 0.8g of triphenyl phosphite are put into a polymerization reactor, and a high-level tank of the polymerization reactor is connected, and 230g of a ring-opening protecting agent DMI and 0.5mol of adipic acid are put into the reactor; vacuum nitrogen replacement is performed, and the nitrogen pressurization of the system is 0.2MPa. Heating the polymerization kettle, melting at 110 ℃, starting polymerization stirring, keeping the temperature at 110 ℃ for half an hour, continuously heating, keeping the temperature at 230 ℃ within 1 hour, keeping the pressure of the polymerization kettle at 0.45MPa, keeping the temperature for 3 hours (preliminary ring-opening polymerization), starting to drop a ring-opening protective agent DMI and a molecular weight regulator in a high-level tank, dropwise adding for 3 hours, controlling the temperature to 248 ℃, controlling the pressure to 0.5MPa, dropwise adding for 3 hours, starting to release pressure after the polymerization (preliminary polymerization for 3 hours and dropwise adding for 3 hours) is completed for 6 hours, keeping the temperature at 250 ℃, and starting to cool and desolventize the pressure release time for 45 minutes and recycling unreacted caprolactam, wherein the generated carboxyl-terminated polyamide oligomer is formed or cut into particles by cooling a steel belt at 150 ℃.
The resulting carboxyl-terminated polyamide oligomer was examined and the results were as follows: acid value 4.42mmol/g; amine group value 0.30mmol/g; the ratio of the acid value to the amino value is 14.7, the caprolactam conversion rate is 94.2%, the mass spectrum is shown in fig. 6, the maximum molecular weight 679 (Mn=113n+146), the maximum polymerization degree n is 4.7, the integral calculation average polymerization degree n is 2.72, and the molecular weight distribution is wider.
Comparative example 2 the same as example 1 except that the preliminary ring-opening polymerization reaction of example 1 was 1 hour and the preliminary ring-opening polymerization reaction of comparative example 2 was 3 hours, the molecular weight distribution of the polyamide oligomer prepared in comparative example 2 was wider than that of example 1.
Comparative example 3
1.0mol of caprolactam, 6.0g of deionized water, 0.6g of N, N' -bis (4-amino-2, 6-tetramethylpiperidinyl) -1, 3-benzenedicarboxamide and 0.8g of triphenyl phosphite are put into a polymerization reactor, and a high-level tank of the polymerization reactor is connected, and 230g of a ring-opening protecting agent DMI and 0.5mol of adipic acid are put into the reactor; vacuum nitrogen replacement is performed, and the nitrogen pressurization of the system is 0.2MPa. Heating the polymerization kettle, melting at 110 ℃, starting polymerization stirring, keeping the temperature at 110 ℃ for half an hour, continuously heating, keeping the temperature at 230 ℃ within 1 hour, keeping the pressure of the polymerization kettle at 0.45MPa, adding a ring-opening protective agent and a molecular weight regulator in a high-level tank into the polymerization kettle at one time after keeping the temperature for 1 hour (preliminary ring-opening polymerization), controlling the temperature to 248 ℃, controlling the pressure to 0.5MPa, starting pressure relief after 3 hours of polymerization, keeping the temperature at 250 ℃, starting cooling and desolventizing for 45 minutes, recycling unreacted caprolactam, and cooling and shaping or granulating the generated carboxyl-terminated polyamide oligomer at 150 ℃ by steel belts.
The resulting carboxyl-terminated polyamide oligomer was examined and the results were as follows: acid value 5.43mmol/g; amine group value 0.60mmol/g; the ratio of acid value to amino value is 9, the caprolactam conversion rate is 93.5%, the mass spectrum is shown in fig. 7, the maximum molecular weight 679 (mn=113n+146), the maximum polymerization degree n is 3.0, the integral calculation average polymerization degree n is 1.96, and the molecular weight distribution is wider.
Comparative example 3 is the same as example 1 except that the ring-opening protecting agent and the molecular weight modifier of example 1 are added dropwise over 3 hours, and comparative example 3 is added at one time, and compared with the examples, the ratio of the acid value to the amine value of the polyamide oligomer prepared in comparative example 3 is lower, and the molecular weight distribution is wider than that of example 1, which means that the ring-opening protecting agent and the molecular weight modifier are added at an excessively high rate or at one time, which is not beneficial to improving the end-capping purity, and is also not beneficial to obtaining the polyamide oligomer with a narrower molecular weight distribution range.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (6)
1. A method for preparing a polyamide oligomer terminated by active groups, wherein the active groups are carboxyl groups or amino groups, and the method is characterized by comprising the following steps:
(1) Taking the lactam as a main raw material, taking one or more of deionized water, linear amino acid and active group terminated polyamide oligomer with polymerization degree less than or equal to 3 as a catalyst, heating to melt the raw material, uniformly stirring, and heating to 210 ℃ or above to cause the lactam to undergo preliminary ring-opening polymerization for 0.5-2 hours; the cyclic lactam is cyclic lactam with 4-7 membered ring; the linear amino acid is one or more of omega-aminobutyric acid, omega-aminopentanoic acid, omega-aminocaproic acid, omega-aminoheptanoic acid, omega-aminocaprylic acid and omega-aminononanoic acid; the active group terminated polyamide oligomer with the polymerization degree less than or equal to 3 is carboxyl terminated polyamide oligomer with the polymerization degree less than or equal to 3, or is amino terminated polyamide oligomer with the polymerization degree less than or equal to 3;
(2) Heating to 230 ℃ and above, and when the pressure reaches 0.3MPa and above, dropwise adding a ring-opening protective agent and a molecular weight regulator into the reaction system, controlling the temperature to 230-250 ℃ and the pressure to 0.3-0.6 MPa in the dropwise adding process, and capping the polyamide obtained by preliminary ring-opening polymerization in the step (1) and controlling the molecular weight of the obtained polyamide; the ring-opening protective agent is 1, 3-dimethyl-2-imidazolone, 1, 3-dimethyl-3, 4,5, 6-tetrahydro-2-pyrimidinone or N-methylpyrrolidone; the molecular weight regulator is dicarboxylic acid or diamine, and the dicarboxylic acid is aliphatic dicarboxylic acid with 2-15 carbon atoms, alicyclic dicarboxylic acid with 2-15 carbon atoms or aromatic dicarboxylic acid with 8-20 carbon atoms; the diamine is aliphatic diamine with 2-10 carbon atoms, alicyclic diamine with 5-20 carbon atoms, aromatic diamine with 6-20 carbon atoms, polyether amine with 150-2003 molecular weight or alkali metal salt of 4,4 '-diaminostilbene-2, 2' -disulfonic acid;
(3) Decompression is carried out after the reaction is finished, unreacted raw materials and byproducts generated in the reaction process are removed through cooling, and an active group terminated polyamide oligomer is obtained, wherein the active group is carboxyl or amino;
when the active group of the active group terminated polyamide oligomer is carboxyl, controlling the dropping speed in the step (2) to ensure that the ratio of the acid value to the amino value of the polyamide oligomer is more than or equal to 15; when the active group of the active group terminated polyamide oligomer is an amino group, controlling the dropping speed in the step (2) to enable the ratio of the amino group value to the acid value of the polyamide oligomer to be more than or equal to 15.
2. The method of claim 1, wherein the reactive group terminated polyamide oligomer has a degree of polymerization of 2 to 20, the molar ratio of the cyclic lactam to the molecular weight regulator is 20:1 to 2:1, and the catalyst is used in an amount of less than or equal to 1wt% of the cyclic lactam; the mass of the ring-opening protective agent is 1-2 times of that of the lactam.
3. The process according to claim 1, wherein the preliminary ring-opening polymerization in the step (1) is carried out at a reaction temperature of 210℃to 230℃and a pressure of 0.3 to 0.6MPa.
4. The preparation method of claim 1, wherein the polymerization degree of the polyamide oligomer is 2-20, each mole of the lactam participates in the reaction, the corresponding addition of the molecular weight regulator and the ring-opening protecting agent is completed within 2-4 hours, and the end capping ratio of the obtained polyamide oligomer is more than 15.
5. The process according to claim 1, wherein the pressure is released after the preliminary ring-opening polymerization of the cyclic lactam in step (1) is started to the end of the reaction in step (3) for 3 to 6 hours.
6. The production method according to claim 1, wherein the preliminary ring-opening polymerization in step (1) is carried out in a polymerization vessel connected to an elevated tank into which the ring-opening protecting agent and the molecular weight regulator are put through a communicating vessel; before the preliminary polymerization reaction, the polymerization kettle and the elevated tank are vacuumized, then are replaced by inert gas, and then maintain positive pressure, so that the influence of air in the polymerization reaction is avoided, and the reaction system is conveniently dripped with a ring-opening protective agent and a molecular weight regulator in the step (2) through the connection of a communicating vessel.
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| US5777067A (en) * | 1995-11-06 | 1998-07-07 | Mitsubishi Chemical Corporation | Method for producing polyamide resin from caprolactam |
| JP2007231049A (en) * | 2006-02-27 | 2007-09-13 | Toray Ind Inc | Manufacturing method of polyamide |
| CN102127221A (en) * | 2010-12-24 | 2011-07-20 | 肖文华 | Production method of caprolactam polymer with low cyclic oligomer content |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5777067A (en) * | 1995-11-06 | 1998-07-07 | Mitsubishi Chemical Corporation | Method for producing polyamide resin from caprolactam |
| JP2007231049A (en) * | 2006-02-27 | 2007-09-13 | Toray Ind Inc | Manufacturing method of polyamide |
| CN102127221A (en) * | 2010-12-24 | 2011-07-20 | 肖文华 | Production method of caprolactam polymer with low cyclic oligomer content |
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