End-modified polyamide resin, method for producing the same, composition, and molded article

Abstract

The present application provides a kind of terminal modified polyamide resin and its manufacturing method.The manufacturing method is carried out polymerization in the presence of polyamide monomer, compound for terminal modification shown in formula I and boric acid compound, X-(R1-O)n-R2 Formula IIn formula I, the range of n is 2-100, each R1 Same or different, it is alkylene with carbon atom number 2-10, R2 It is alkyl with carbon atom number 1-30, X is selected from NH2-, NH (CH3)-, HO-, HOOC-, O=C=N- and one or more;Wherein with the polyamide monomer is 100 parts by weight, the addition amount of the compound for terminal modification shown in formula I is 0.05-25 parts by weight, the addition amount of the boric acid compound is 0.005-1.0 parts by weight.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high molecular material, and particularly relates to a terminal modified polyamide resin, a preparation method, a composition and a molded product. BACKGROUND

[0002] Polyamide resin is widely used in fibers, various containers, films, electronic components, automobile parts, mechanical parts and various molded products due to its excellent mechanical properties, heat resistance and other characteristics.

[0003] In recent years, the demand for miniaturization, complex shape, thin-walled, lightweight and other requirements of molded products has been increasing, therefore, the research and development of materials with excellent molding processability and mechanical properties has become particularly important. Generally speaking, as the molecular weight of polyamide resin increases, the mechanical properties of polyamide resin also increase. However, the increase of molecular weight also brings negative effects such as increase of melt viscosity, decrease of molding processability, etc. Although the melt viscosity can be reduced by increasing the molding processing temperature, but due to the thermal decomposition of polyamide resin at higher molding processing temperature, the molecular weight decreases and gas is generated, thereby causing problems such as decrease of mechanical properties, appearance of molded products, etc. In addition, in recent years, there are higher and higher requirements for the thermal conductivity, electrical conductivity, material rigidity and other properties of high molecular materials, in order to improve the above properties, a large amount of fillers with excellent thermal conductivity, electrical conductivity or reinforcing fillers need to be used for high filling of the resin. In the process of filling the resin with a high proportion of fillers, due to the large amount of fillers, the viscosity of the system increases sharply, thereby easily causing shear heat generation leading to degradation of resin properties, and poor dispersion of fillers, etc. In addition, since polyamide resin has reactive carboxyl and amino terminal groups, in the process of filling with some fillers which are easy to react with the above terminal groups, the fillers are easy to react with the terminal groups of polyamide resin, leading to degradation of resin properties.

[0004] Patent document 1 discloses a low melt viscosity terminal modified polyamide resin with a specific terminal group structure, which reduces the melt viscosity of polyamide resin by introducing a polyether structure into the terminal of polyamide. However, due to the capping effect of monoamine-based polyether on the active terminal of polyamide, it takes a long time to increase the polymerization degree, thereby leading to low production efficiency. In patent document 2, by further limiting the content of polyether terminal structure, the molecular weight of terminal modified polyamide resin and other characteristics, a polyamide resin with lower melt viscosity is obtained. However, due to the use of monocarboxylic compound as capping agent in addition to monoamine-based polyether to control the molecular weight, the polymerization speed is further reduced.

[0005] On the other hand, in the polymerization of the polyamide resin having a polyether end structure, since the polyether end has a hydrophilic property and the polyamide main chain has a hydrophobic property, the molecular chain formed by the combination of both has a structure similar to a surfactant in which one end is hydrophilic and the other end is hydrophobic. The above structure plays a stabilizing role for the bubbles generated by the condensation of water vapor and the volatilized monomers during the polycondensation of the polyamide, making it difficult for the bubbles to be discharged from the polymerization product, thereby causing a large number of bubbles to exist in the polymer strand discharged from the polymerization kettle at the end of the polymerization, forming a foamed structure, and further affecting the pelletizability of the polymer strand. In addition, when adipic acid is included in the monomers forming the polyamide, the adipic acid structural unit at the end of the polyamide easily undergoes a cyclization reaction, thereby causing the deterioration and decomposition of the polyamide. At the same time, when the polyamide is used as a base resin and blended with an alkaline filler, the carboxyl group at the end of the polyamide molecular chain easily reacts with the alkaline filler, thereby causing the decomposition of the alkaline filler.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: International Patent Application Publication WO2015 / 182693

[0009] Patent Document 2: International Patent Application Publication WO2018 / 101054 SUMMARY

[0010] The present application has an object to solve the problems in the prior art described above, and to provide a production method of a terminal-modified polyamide resin capable of greatly shortening the polymerization time of the terminal-modified polyamide resin while suppressing the foaming of the polymerization product by suppressing the volatilization of the monomers during the polymerization, particularly the volatilization of the diamine monomers, thereby improving the pelletizability of the polymer strand, and a terminal-modified polyamide resin capable of simultaneously satisfying excellent mechanical properties and processability.

[0011] To solve the above problems, the present application is constituted by the following:

[0012] 1. A production method of a terminal-modified polyamide resin, characterized by carrying out polymerization in the presence of a polyamide monomer, a terminal-modification compound represented by Formula I, and a boronic acid compound,

[0013] X-(R1-O)n-R2 Formula I

[0014] In Formula I, n is in the range of 2 to 100, each R1 is the same or different and is an alkylene group having 2 to 10 carbon atoms, R2 is an alkyl group having 1 to 30 carbon atoms, and X is one or more selected from the group consisting of NH2-, NH(CH3)-, HO-, HOOC-, O=C=N-, and ​

[0015] wherein the polyamide monomer is 100 parts by weight, the amount of the compound for end modification shown in formula I is 0.05 to 25 parts by weight, and the amount of the boronic acid compound is 0.005 to 1.0 parts by weight.

[0016] 2. The method for producing an end-modified polyamide resin according to the above 1, wherein the compound for end modification shown in formula I and the boronic acid compound can be added at any time before the end of polymerization.

[0017] 3. The method for producing an end-modified polyamide resin according to the above 1, wherein the boronic acid compound is one or more selected from the group consisting of boric acid, a salt of boric acid, and an organic boronic acid compound.

[0018] 4. The method for producing an end-modified polyamide resin according to the above 1, wherein the polyamide monomer is one or more selected from the group consisting of a combination of a diamine having 2 to 20 carbon atoms and a diacid having 2 to 20 carbon atoms, an amino acid having 4 to 20 carbon atoms, a lactam having 4 to 20 carbon atoms, a mixture of the above polyamide monomers, and a salt thereof.

[0019] 5. The method for producing an end-modified polyamide resin according to the above 1, wherein the amounts of the polyamide monomer and the compound for end modification shown in formula I satisfy the relationship that the molar ratio of total amino groups to total carboxyl groups is 1.010 or more and 1.10 or less.

[0020] 6. The method for producing an end-modified polyamide resin according to the above 5, wherein the amounts of the polyamide monomer and the compound for end modification shown in formula I satisfy the relationship that the molar ratio of total amino groups to total carboxyl groups is 1.020 or more and 1.050 or less.

[0021] 7. The method for producing an end-modified polyamide resin according to claim 1, wherein 5 to 900 parts by weight of water is further added, based on 100 parts by weight of the polyamide monomer.

[0022] 8. An end-modified polyamide resin, wherein the end-modified polyamide resin has a terminal structure shown in formula II and boron element,

[0023] -Y-(R1-O)n-R2 Formula II

[0024] In formula II, n is in the range of 2 to 100, each R1 is the same or different, and is an alkylene group having 2 to 10 carbon atoms, R2 is an alkyl group having 1 to 30 carbon atoms, and Y is one or more selected from the group consisting of -NH-, -N(CH3)-, -O-, -C(=O)-, -C(=O)-NH-, -NH-C(=O)-NH-, and -CH2-CH(OH)-;

[0025] the content of the terminal structure represented by formula II in the terminal-modified polyamide resin is 0.05 to 25 wt% based on the total weight of the terminal-modified polyamide resin,

[0026] the content of the boron element in the terminal-modified polyamide resin is 10 to 2000 ppm based on the total weight of the terminal-modified polyamide resin.

[0027] 9. The terminal-modified polyamide resin according to claim 8, wherein n in the terminal structure represented by formula II is in the range of 16 to 100.

[0028] 10. The terminal-modified polyamide resin according to claim 8, wherein each R1 in the terminal structure represented by formula II is at least one of -CH2-CH2-, -CH2-CH2-CH2-, and -CH(CH3)-CH2-.

[0029] 11. The terminal-modified polyamide resin according to claim 8, wherein when the terminal-modified polyamide resin is prepared into a terminal-modified polyamide resin solution having a concentration of 0.01 g / ml using 96 wt% sulfuric acid as a solvent, the relative viscosity ηr measured at 25°C is in the range of 1.1 to 4.0.

[0030] 12. The terminal-modified polyamide resin according to claim 8, wherein the weight average molecular weight Mw of the terminal-modified polyamide resin measured by gel permeation chromatography is in the range of 10,000 to 400,000.

[0031] 13. The terminal-modified polyamide resin according to claim 8, wherein the melting point of the terminal-modified polyamide resin is 215°C or higher.

[0032] 14. The terminal-modified polyamide resin according to claim 8, wherein the amino group concentration in the terminal-modified polyamide resin is in the range of 105 to 400 mol / t.

[0033] 15. The terminal-modified polyamide resin according to claim 8, wherein the carboxyl group concentration in the terminal-modified polyamide resin is 100 mol / t or less.

[0034] 16. The end-modified polyamide resin according to any one of claims 8 to 15, wherein the ratio of the amino group concentration to the carboxyl group concentration in the end-modified polyamide resin is 4.0 or more and 50 or less.

[0035] 17. An end-modified polyamide resin composition comprising the end-modified polyamide resin according to any one of claims 8 to 16.

[0036] 18. A molded article comprising the end-modified polyamide resin according to any one of claims 8 to 16 or the end-modified polyamide resin composition according to claim 17.

[0037] Effects of the Invention

[0038] According to the present application, by performing polymerization of a polyamide with a specific end modification in the presence of a boronic acid compound, it is possible to suppress foaming of the polymerization product by suppressing volatilization of monomers (particularly, volatilization of diamine monomers) at the time of polymerization while greatly shortening the polymerization time of the end-modified polyamide resin, and thus an end-modified polyamide resin with excellent pelletizability of the polymer strand discharged can be obtained. Furthermore, the end-modified polyamide resin of the present application can satisfy both excellent mechanical properties and processability.

[0039] The above summary of the application will be described in detail below:

[0040] In the method for producing the end-modified polyamide resin of the present application, polymerization is performed in the presence of a compound for end modification represented by Formula I and a boronic acid compound,

[0041] X-(R1-O)n-R2 Formula I

[0042] In Formula I, n is in the range of 2 to 100, each R1 is the same or different and is an alkylene group having 2 to 10 carbon atoms, R2 is an alkyl group having 1 to 30 carbon atoms, and X is one or more selected from the group consisting of NH2-, NH(CH3)-, HO-, HOOC-, O=C=N-, and

[0043] wherein the amount of the compound for end modification represented by Formula I is 0.05 to 25 parts by weight and the amount of the boronic acid compound is 0.001 to 1.0 parts by weight, based on 100 parts by weight of the polyamide monomer.

[0044] ​The method for producing the terminal-modified polyamide resin of the present application is a method in which a polyamide monomer, a terminal-modifying compound represented by Formula I, and other components as necessary are mixed and reacted in the presence of a boronic acid compound. Specifically, the following methods can be exemplified: a method in which a polyamide monomer, a terminal-modifying compound represented by Formula I, a boronic acid compound, and other components as necessary are mixed in advance, and then condensed by heating; a method in which a terminal-modifying compound represented by Formula I and a boronic acid compound are added during the polymerization of a polyamide monomer raw material, and reacted; and the like. The above reaction is preferably performed after further adding water. On the other hand, the method for producing the terminal-modified polyamide resin of the present application can employ a method in which melt polymerization is performed at a temperature above the melting point of the terminal-modified polyamide resin, or a method in which solid phase polymerization is performed at a temperature below the melting point of the terminal-modified polyamide resin.

[0045] In the production of the polyamide of the present application, a diamine and a diacid can be used as a polyamide monomer for polymerization, an amino acid or a lactam can be used as a monomer, and a mixture of these monomers or a salt thereof can also be used. In the case where a diamine and a diacid are used as monomers, at least one of a diacid having 2 to 20 carbon atoms and at least one of a diamine having 2 to 20 carbon atoms can be exemplified. In the case where an amino acid or a lactam is used as a monomer, an amino acid having 4 to 20 carbon atoms or a lactam having 4 to 20 carbon atoms can be exemplified. The above monomers can be polymerized alone (homopolymer) or two or more kinds of them can be copolymerized (copolymer). In the case where an amino acid or a lactam is used as a monomer, in order to adjust the total amino / carboxyl molar ratio of the added raw materials, the above diamine or diacid can also be added additionally.

[0046] As the above amino acid, specifically, the following can be exemplified but are not limited thereto: 6-aminohexanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, 4-aminomethylbenzoic acid, and the like.

[0047] As the above lactam, specifically, the following can be exemplified but are not limited thereto: ε-caprolactam, ω-undecalactam, ω-dodecalactam, and the like.

[0048] As the above diamine, specifically, the following can be exemplified but are not limited thereto: aliphatic diamines such as ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-pentanediamine, and 2-methyl-1,8-octanediamine; alicyclic diamines such as cyclohexanediamine and 4,4'-diaminodicyclohexylmethane, 4,4'-methylenebis(2-methylcyclohexylamine); and aromatic diamines such as xylylenediamine.

[0049] As the above-mentioned dibasic acid, the following examples can be specifically mentioned, but are not limited thereto: aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, or dodecanedioic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2-chloro-l,4-benzenedicarboxylic acid, 2-methyl-l,4-benzenedicarboxylic acid, or 5-methylisophthalic acid, 5-sulfonic acid sodium isophthalic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Alkyl diesters and diacyl chlorides derived from the dibasic acids can also be mentioned as the polyamide monomers.

[0050] Of the above-mentioned monomers, 6-aminohexanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, ε-caprolactam, ω-undecanolactam, ω-dodecanolactam, butanediamine, pentanediamine, hexanediamine, decanediamine, undecanediamine, dodecanediamine, adipic acid, sebacic acid, dodecanedioic acid are preferred; and ε-caprolactam, butanediamine, hexanediamine, adipic acid, or sebacic acid are further preferred.

[0051] The present application can use the above-mentioned monomers to make the polyamide molecular chain main body other than the terminal structure formed by the terminal modification compound of formula I a polyamide homopolymer or copolymer. In the present application, from the viewpoint of maintaining the heat resistance of the terminal-modified polyamide resin, it is preferred that 80 mol% or more of the above-mentioned polyamide monomers be contained in 100 mol% of all the polyamide monomers, more preferably 90 mol% or more, and most preferably 100 mol%.

[0052] In the method for producing the terminal-modified polyamide resin of the present application, the terminal modification compound of formula I is further added.

[0053] X-(R1-O)n-R2 Formula I

[0054] In the above-mentioned formula I, n is in the range of 2 to 100. When n is less than 2, the addition of the terminal modification compound of formula I in the range of the addition amount of the present application can result in a slower polymerization rate. It is preferred that n be 4 or more, further preferred that n be 8 or more, and most preferred that n be 16 or more. On the other hand, when n is greater than 100, the heat resistance of the terminal modification compound of formula I becomes poor. It is preferred that n be 70 or less, further preferred that n be 50 or less, and most preferred that n be 25 or less.

[0055] In the above formula I, each R1 is the same or different and is an alkylene group having 2 to 10 carbon atoms. Specific examples of R1 include -CH2-CH2-, -CH2-CH2-CH2-, -CH(CH3)-CH2-, -CH2-CH2-CH2-CH2-, -CH2-CH2-CH2-CH2-CH2-, -CH2-CH2-CH2-CH2-CH2-CH2-, and the like. In view of the affinity with the polyamide, R1 is preferably an alkylene group having 2 to 6 carbon atoms, and further preferably an alkylene group having 2 to 4 carbon atoms. R1 can be a combination of different alkylene groups, and is preferably at least one of -CH2-CH2-, -CH2-CH2-CH2-, and -CH(CH3)-CH2-.

[0056] In the above formula I, R2 is an alkyl group having 1 to 30 carbon atoms. The smaller the number of carbon atoms in R2, the higher the affinity with the polyamide, and therefore R2 is preferably an alkyl group having 1 to 20 carbon atoms, further preferably an alkyl group having 1 to 10 carbon atoms, and more further preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group.

[0057] In the above formula I, X is one or more selected from the group consisting of NH2-, NH(CH3)-, HO-, HOOC-, O=C=N-, and NH2- is preferred because of its excellent reactivity with the polyamide monomer.

[0058] The number average molecular weight of the terminal modification compound represented by the above formula I is preferably 750 to 10,000. By making the number average molecular weight 750 or more, the melt viscosity of the terminal-modified polyamide resin product can be further reduced. More preferably, the number average molecular weight is 800 or more, and further preferably 900 or more. On the other hand, by making the number average molecular weight 10,000 or less, the affinity with the main structural unit of the polyamide resin can be further improved. More preferably, the number average molecular weight is 5,000 or less, further preferably 2,500 or less, and most preferably 1,500 or less.

[0059] Specific examples of the terminal modification compound represented by the above formula I include methoxypoly(ethylene glycol)amine, methoxypoly(l,3-propanediol)amine, methoxypoly(propylene glycol)amine, methoxypoly(l,4-butanediol)amine, methoxypoly(ethylene glycol)poly(propylene glycol)amine, and the like. In the case where two kinds of polyalkylene glycols are included, a block polymer structure or a random copolymer structure can be formed. In addition, two or more of the above terminal modification compounds can be used.

[0060] In the production method of the terminal-modified polyamide of the present application, the amount of the terminal-modifying compound represented by Formula I is 0.05 to 25 parts by weight per 100 parts by weight of the polyamide monomers. By making the amount of the terminal-modifying compound represented by Formula I 0.05 parts by weight or more, the melt viscosity of the terminal-modified polyamide can be further reduced, preferably 1 part by weight or more, further preferably 1.5 parts by weight or more, and more further preferably 2 parts by weight or more. On the other hand, by making the amount of the terminal-modifying compound represented by Formula I 25 parts by weight or less, the polymerization rate can be maintained while the mechanical properties and crystallinity of the terminal-modified polyamide are maintained, preferably 15 parts by weight or less, further preferably 10 parts by weight or less, and more further preferably 5 parts by weight or less.

[0061] In the production method of the terminal-modified polyamide resin of the present application, the terminal-modifying compound represented by Formula I described above can be added at any time before the end of the polymerization. That is, the terminal-modifying compound represented by Formula I can be added to the reaction system at the start of the polymerization together with the polyamide monomers, or at any time during the polymerization.

[0062] In the production method of the terminal-modified polyamide resin of the present application, a boronic acid compound is added in addition to the polyamide monomers and the terminal-modifying compound represented by Formula I described above. The addition of the boronic acid compound not only increases the polymerization rate, but also suppresses the foaming of the polymer by suppressing the volatilization of the monomers during the polymerization, particularly the volatilization of the diamine monomers. In addition, by suppressing the volatilization of the diamine monomers, the amount of the diamine in the reaction system increases, and thus the reaction with the carboxyl group can be performed more efficiently.

[0063] The type of the boronic acid compound is not particularly limited in the present application, and can be a boronic acid, or other compounds derived from a boronic acid such as borate salts, organic boronic acid compounds, and the like. Specific examples that can be mentioned, but are not limited to, include: boronic acid (B(OH)3), metaboric acid (HBO2), boric anhydride (B2O3), sodium tetraborate (Na2B4O7) and its compounds containing crystal water, and the like borate salts, and, as organic boronic acid compounds, for example, alkyl boronic acids (RB(OH)2) in which the hydroxyl group (-OH) of the boronic acid is substituted with an alkyl group (-R) including but not limited to a methyl group (-CH3) and a propenyl group (-CH=CHCH3), aryl boronic acids (ArB(OH)2) in which the hydroxyl group (-OH) of the boronic acid is substituted with an aryl group (-Ar) including but not limited to a phenyl group and a thienyl group, and esters thereof. One of the above boronic acid compounds can be used alone, or two or more of them can be used in combination. In view of the compatibility of the added boronic acid compound with the polyamide monomers and the water added during the polymerization, boronic acid, metaboric acid, boric anhydride, borate salts are preferred, and boronic acid is further preferred.

[0064] In the production method of the terminal-modified polyamide resin of the present application, the amount of the boronic acid compound added is 0.005 to 1.0 parts by weight based on 100 parts by weight of the polyamide monomer. By making the amount of the boronic acid compound added 0.005 parts by weight or more and 1.0 parts by weight or less, foaming can be suppressed while the polymerization rate is ensured, and the amount is preferably 0.01 parts by weight or more, further preferably 0.02 parts by weight or more, and more further preferably 0.03 parts by weight or more. The amount of the boronic acid compound added is preferably 0.5 parts by weight or less, further preferably 0.1 parts by weight or less, and more further preferably 0.05 parts by weight or less.

[0065] In the production method of the terminal-modified polyamide resin of the present application, the above boronic acid compound can be added at any timing before the end of polymerization. That is, the boronic acid compound can be added to the reaction system together with the polyamide monomer at the start of polymerization, or can be added to the reaction system at any timing during polymerization. Of these, it is preferred that the boronic acid compound be added to the reaction system together with the polyamide monomer at the start of polymerization.

[0066] In the production method of the terminal-modified polyamide resin of the present application, the molar ratio of the total amino groups to the total carboxyl groups of the added polyamide monomer and the terminal-modification compound represented by Formula I is not particularly limited, and the molar ratio of the total amino groups to the total carboxyl groups is preferably in the range of 0.9 to 1.1 in view of the polymerization rate. In order to reduce the carboxyl group concentration of the terminal-modified polyamide resin, the molar ratio of the total amino groups to the total carboxyl groups is preferably 1.010 or more, further preferably 1.020 or more, and more further preferably 1.030 or more. On the other hand, in view of the polymerization rate, the molar ratio of the total amino groups to the total carboxyl groups is preferably 1.10 or less, further preferably 1.050 or less, and more further preferably 1.040 or less. Note that, in the case where the polyamide monomer is a lactam, the molar ratio of the total amino groups to the total carboxyl groups is calculated using the amounts of the amino groups and the carboxyl groups obtained by hydrolysis of the amide groups.

[0067] In the production method of the terminal-modified polyamide resin of the present application, 5 to 900 parts by weight of water is preferably further added based on 100 parts by weight of the polyamide monomer. By adding 5 parts by weight or more and 900 parts by weight or less of water, not only can the polyamide monomer and the boronic acid compound be uniformly dissolved and the boronic acid compound be uniformly dispersed in the polyamide monomer, but also the volatilization of the diamine during polymerization can be suppressed. The amount of water added is further preferably 10 parts by weight or more, and more further preferably 50 parts by weight or more. On the other hand, the amount of water added is further preferably 200 parts by weight or less, and more further preferably 100 parts by weight or less.

[0068] In the preparation method of the end-modified polyamide resin of the present invention, other additives may be added as needed, such as defoamers, flame retardants, antioxidant stabilizers, antibacterial additives, optical brighteners, dyeable agents, or other dyes commonly known in the art. Adding a defoamer can further suppress foaming during the polymerization process. The defoamer can be selected from silicone-based defoamers, or from other commonly used types of defoamers such as polyether and modified polyether defoamers, and mineral oil defoamers. The above additives can be added at any time before the end of polymerization. That is, the additives can be added to the reaction system together with the polyamide monomer at the beginning of polymerization, or they can be added to the reaction system all at once or in multiple portions at any time during polymerization.

[0069] The following is a detailed description of end-modified polyamide resins.

[0070] The end-modified polyamide resin of the present invention has the end structure shown in Formula II and boron element.

[0071] -Y-(R1-O)n-R2 Formula II

[0072] In Formula II, n ranges from 2 to 100, each R1 may be the same or different, and is an alkylene group with 2 to 10 carbon atoms; R2 is an alkyl group with 1 to 30 carbon atoms; Y is one or more selected from -NH-, -N(CH3)-, -O-, -C(=O)-, -C(=O)-NH-, -NH-C(=O)-NH-, and -CH2-CH(OH)-; the content of the end structure shown in Formula II in the end-modified polyamide resin is 0.05 to 25 wt% of the total weight of the end-modified polyamide resin, and the content of boron in the end-modified polyamide resin is 10 to 2000 ppm of the total weight of the end-modified polyamide resin.

[0073] The polyamide main chain structure of the terminal-modified polyamide resin of the present application can be exemplified by, but not limited to, the following: polycaprolactam (nylon 6), polyundecanolactam (nylon 11), polydodecanolactam (nylon 12), poly(hexamethylene adipate) (nylon 66), poly(hexamethylene azelate) (nylon 46), poly(hexamethylene sebacate) (nylon 56), poly(hexamethylene decanedioate) (nylon 410), poly(hexamethylene dodecanedioate) (nylon 510), poly(hexamethylene sebacate) (nylon 610), poly(hexamethylene dodecanedioate) (nylon 612), poly(hexamethylene decanedioate) (nylon 1010), poly(hexamethylene sebacate) (nylon 1012), poly(caprolactam / hexamethylene adipate) copolymer (nylon 6 / 66), poly(m-xylylene adipamide) (MXD6), poly(m-xylylene sebacamide) (MXD10), poly(p-xylylene sebacamide) (PXD10), poly(nonamethylene terephthalamide) (nylon 9T), poly(decamethylene terephthalamide) (nylon 10T), poly(undecamethylene terephthalamide) (nylon 11T), poly(dodecamethylene terephthalamide) (nylon 12T), poly(p-xylylene terephthalamide / hexamethylene terephthalamide) copolymer (nylon 5T / 6T), poly(p-xylylene terephthalamide-2-methylhexamethylene terephthalamide) copolymer (nylon M5T / 6T), poly(hexamethylene adipamide / hexamethylene terephthalamide) copolymer (nylon 66 / 6T), poly(hexamethylene adipamide / hexamethylene isophthalamide) copolymer (nylon 66 / 6I), poly(hexamethylene adipamide / hexamethylene terephthalamide / hexamethylene isophthalamide) copolymer (nylon 66 / 6T / 6I), poly(4,4'-methylenebis(2-methylcyclohexylamine) terephthalamide) (nylon MACMT), poly(4,4'-methylenebis(2-methylcyclohexylamine) isophthalamide) (nylon MACMI), poly(4,4'-methylenebis(2-methylcyclohexylamine) dodecanediamide) (nylon MACM12), poly(4,4'-methylenebis(cyclohexylamine) terephthalamide) (nylon PACMT), poly(4,4'-methylenebis(cyclohexylamine) isophthalamide) (nylon PACMI), poly(4,4'-methylenebis(cyclohexylamine) dodecanediamide) (nylon PACM12), or a copolymer of the above polymers.

[0074] In order to obtain a terminal-modified polyamide resin having a good crystallinity, the polyamide main chain structure of the above terminal-modified polyamide resin is preferably polycaprolactam (nylon 6), poly(hexamethylene adipate) (nylon 66), poly(hexamethylene sebacate) (nylon 56), poly(hexamethylene decanedioate) (nylon 410), poly(hexamethylene dodecanedioate) (nylon 510), poly(hexamethylene sebacate) (nylon 610), poly(nonamethylene terephthalamide) (nylon 9T), or poly(decamethylene terephthalamide) (nylon 10T).

[0075] The main chain structure of the end-modified polyamide resin can be composed of one of the above-mentioned main chain structures alone, or can be composed of two or more of the above-mentioned main chain structures in combination. Of the repeating units of the main chain of the end-modified polyamide resin used in the present application, it is preferable that 80 mol% or more be composed of the structural units derived from the above-mentioned monomer raw materials (based on 100 mol% of the repeating units of the polyamide main chain structure). In view of heat resistance and crystallinity, it is preferable that 90 mol% or more be composed of the structural units derived from the above-mentioned monomer raw materials, and it is most preferable that 100 mol% be composed of the structural units derived from the above-mentioned monomer raw materials.

[0076] The end-modified polyamide resin of the present application improves the mobility of the entire molecular chain by introducing the flexible polyether structure represented by Formula II into the polyamide end, thereby reducing the melt viscosity, while the crystallinity of the end-modified polyamide resin is maintained.

[0077] In the above-mentioned Formula II, n is in the range of 2 to 100. As with n in the above-mentioned Formula I, it is preferable that n be 4 or more, it is further preferable that n be 8 or more, and it is most preferable that n be 16 or more. On the other hand, it is preferable that n be 70 or less, it is further preferable that n be 50 or less, and it is most preferable that n be 25 or less.

[0078] In the above-mentioned Formula II, each R1 is the same or different, and is an alkylene group having 2 to 10 carbon atoms, and R2 is an alkyl group having 1 to 30 carbon atoms. R1 and R2 in Formula II can each be the same group as the groups exemplified for R1 and R2 in the above-mentioned Formula I, and the preferable groups are also the same as those described for R1 and R2 in the above-mentioned Formula I.

[0079] In the above-mentioned Formula II, Y is one or more selected from -NH-, -N(CH3)-, -O-, -C(=O)-, -C(=O)-NH-, -NH-C(=O)-NH-, or -CH2-CH(OH)-. In order to make the end-modified polyamide resin of the present application have a lower melt viscosity, it is preferable that the affinity of the polyether end to the polyamide main chain be high, and -Y- is preferably -NH-.

[0080] In the end-modified polyamide resin of the present application, the content of the end structure represented by Formula II is 0.05 to 25 wt% of the total weight of the end-modified polyamide resin. In view of the purpose of reducing the melt viscosity and improving the molding processability, it is preferable that the content of the end structure be 0.1 wt% or more, it is further preferable that the content be 0.5 wt% or more, it is still further preferable that the content be 1.5 wt% or more, and it is most preferable that the content be 2 wt% or more. On the other hand, by making the content of the end structure represented by Formula II be 25 wt% or less, the crystallinity and mechanical properties of the end-modified polyamide resin can be more favorably maintained, and it is preferable that the content be 15 wt% or less, it is further preferable that the content be 10 wt% or less, and it is still further preferable that the content be 5 wt% or less. Here, the content (wt%) of the end structure represented by Formula II in the above-mentioned end-modified polyamide resin is determined by the following method. 1H-NMR (nuclear magnetic hydrogen spectrum) test.

[0081] The end-modified polyamide resin of the present application further contains boron element, and the content of the boron element is 10 to 2000 ppm based on the total weight of the end-modified polyamide resin. By having the content of the boron element be 10 ppm or more and 2000 ppm or less, not only can foaming during melting of the end-modified polyamide resin be suppressed, but also the reactivity of the polyamide monomer can be improved. The content of the boron element is preferably 20 ppm or more, further preferably 40 ppm or more, and still further preferably 60 ppm or more. On the other hand, the content of the boron element is preferably 1000 ppm or less, further preferably 300 ppm or less, and still further preferably 100 ppm or less. The content of the boron element in the end-modified polyamide resin is determined by adding sulfuric acid and nitric acid to the resin and decomposing the same under microwave irradiation, and then measuring by ICP emission spectrometry.

[0082] When the end-modified polyamide resin of the present application is prepared into a solution having a concentration of 0.01 g / ml using 96 wt% concentrated sulfuric acid as a solvent, the relative viscosity ηr measured at 25°C is preferably 1.1 to 4.0. When ηr is less than 1.1, the toughness of the end-modified polyamide resin is poor. Further preferably, ηr is 1.6 or more, still further preferably 1.7 or more, and most preferably 1.8 or more. On the other hand, when ηr is higher than 4.0, the molecular weight of the end-modified polyamide resin is too high, resulting in high melt viscosity and poor processability. Further preferably, ηr is 3.0 or less, still further preferably 2.5 or less, and most preferably 2.0 or less.

[0083] The weight average molecular weight (Mw) of the end-modified polyamide resin of the present application is preferably 10,000 or more. When Mw is 10,000 or more, the mechanical properties of the end-modified polyamide resin can satisfy practical applications. Further preferably, Mw is 25,000 or more, still further preferably 30,000 or more, and most preferably 35,000 or more. On the other hand, Mw is preferably 400,000 or less. When Mw is 400,000 or less, the melt viscosity of the end-modified polyamide resin is low. Further preferably, Mw is 1,000,000 or less, still further preferably 7,000,000 or less, and most preferably 4,500,000 or less. The weight average molecular weight (Mw) can be determined by gel permeation chromatography (GPC).

[0084] In order to impart good heat resistance to the end-modified polyamide resin of the present application, the melting point (Tm) thereof is preferably 215°C or higher, and further preferably 218°C or higher. Generally, the melting point of a polyamide resin decreases by introducing a flexible structure into the resin by copolymerization, but the present application controls the decrease in the melting point of the polyamide resin to which a specific polyether end structure has been introduced to a minimum range compared to a polyamide not containing the polyether end structure. The decrease in the melting point is preferably 5°C or less, and further preferably 3°C or less. The melting point of the polyamide resin described herein is measured by a differential scanning calorimeter (DSC) by precisely weighing about 3 mg of the polyamide resin, raising the temperature from 20°C at a rate of 20°C / min under a nitrogen atmosphere to a temperature 30°C higher than the temperature To of the endothermic peak appearing, maintaining the temperature for 2 min, lowering the temperature at a rate of 20°C / min to 20°C, and then raising the temperature at a rate of 20°C / min to a temperature 30°C higher than To, and defining the temperature of the endothermic peak appearing in the second temperature-raising process as the melting point (Tm).

[0085] The amino group concentration in the end-modified polyamide resin of the present application is preferably 105 mol / t or more and 400 mol / t or less. By controlling the amino group concentration within the above-mentioned preferable range, it is possible to maintain the mechanical strength required for practical use while preventing the molecular weight from being excessively high. The amino group concentration is further preferably 150 mol / t or more, and still further preferably 190 mol / t or more. On the other hand, the amino group concentration is further preferably 300 mol / t or less, and still further preferably 250 mol / t or less.

[0086] The carboxyl group concentration in the end-modified polyamide resin of the present application is preferably 100 mol / t or less. When the carboxyl group concentration is 100 mol / t or less, the cyclization reaction of the adipic acid structural unit at the end of the end-modified polyamide is suppressed, thereby suppressing the decomposition of the end-modified polyamide resin. In addition, the decomposition of a basic filler can be suppressed when the end-modified polyamide resin is blended with the basic filler. The carboxyl group concentration is further preferably 30 mol / t or less, and still further preferably 15 mol / t or less.

[0087] The ratio of the amino group concentration to the carboxyl group concentration in the end-modified polyamide resin of the present application is preferably 4.0 or more and 50 or less. When the ratio of the amino group concentration to the carboxyl group concentration is within the above-mentioned range, the relative viscosity ηr and the weight average molecular weight Mw of the end-modified polyamide resin are within the above-mentioned preferable ranges. The ratio of the amino group concentration to the carboxyl group concentration is further preferably 10 or more and 40 or less.

[0088] The end-modified polyamide resin composition of the present application will be described in detail below.

[0089] The end-modified polyamide resin composition of the present application refers to a composition obtained by further adding a filler, other kinds of polymers, and various additives to the end-modified polyamide resin.

[0090] The end-modified polyamide resin composition of the present application can further contain a filler. The filler can be exemplified by, but not limited to, the following examples: fibrous inorganic or organic fillers such as glass fibers, carbon fibers, potassium titanate whiskers, zinc oxide whiskers, aluminum borate whiskers, aramid fibers, alumina fibers, silicon carbide fibers, ceramic fibers, graphite fibers, basalt fibers, or metal fibers; non-fibrous inorganic fillers such as wollastonite, zeolite, sericite, kaolin, mica, talc, clay, pyrophyllite, bentonite, montmorillonite, asbestos, silicates, graphite, carbon black, silicon carbide, boron carbide, alumina, silica, magnesium oxide, zirconium oxide, titanium oxide, iron oxide, calcium carbonate, magnesium carbonate, dolomite, calcium sulfate, barium sulfate, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, glass beads, ceramic beads, boron nitride, silicon nitride, aluminum nitride, silicon carbide, or metal powders such as copper powder, aluminum powder, zinc powder. The above non-fibrous inorganic fillers can be in a spherical shape, or in a flaky or other irregular shape, and the above fillers can also be in a hollow form. In addition, the above fillers can be treated with a coupling agent such as an isocyanate compound, an organosilane compound, an organotitanate compound, an organoborane compound, or an epoxy compound. The above montmorillonite can also be an organically modified montmorillonite obtained by cation exchange of interlayer ions with an organic ammonium salt. In the present application, when an end-modified polyamide resin having a low carboxyl group concentration is used, decomposition is less likely to occur even when blended with a basic filler, and thus the above fillers are preferably basic fillers such as calcium carbonate, magnesium carbonate, magnesium hydroxide, calcium hydroxide, aluminum hydroxide. Further, in view of the improvement of the mechanical properties of the end-modified polyamide resin composition and the reduction of the molding shrinkage, the above fillers are preferably fibrous inorganic fillers such as glass fibers, metal fibers, carbon fibers. The above fillers can be added alone or in combination of two or more kinds.

[0091] The content of the above filler in the end-modified polyamide resin composition is preferably 5 to 80 wt% based on the total weight of the end-modified polyamide resin composition. By adding the filler in an amount of 5 wt% or more and 80 wt% or less, the dispersibility of the filler is improved, and the mechanical properties and other properties (e.g., electrical conductivity, thermal conductivity) are improved. Further, the amount of the filler is preferably 40 wt% or more, and more preferably 50 wt% or more, based on the total weight of the end-modified polyamide resin composition. On the other hand, the amount of the filler is further preferably 70 wt% or less.

[0092] Examples of the other types of polymers in the above-mentioned end-modified polyamide resin composition include, but are not limited to, polyethylene, polypropylene and the like polyolefins; modified polyolefins such as polymers (or copolymers) of olefin and / or conjugated diene compounds; polyesters; polycarbonates; polyphenylene ethers; polyphenylene sulfides; liquid crystal polymers; polysulfones; polyethersulfones; ABS resins; SAN resins; polystyrenes; polyamides other than the end-unmodified polyamide resin of the present application; and the like.

[0093] As the other types of polymers, in order to improve the impact resistance of the molded article obtained from the end-modified polyamide resin composition used in the present application and to reduce the shrinkage, it is preferable to use a modified polyolefin such as a polymer (or copolymer) of olefin and / or conjugated diene compounds and the like impact resistant agent.

[0094] Examples of the above-mentioned polymer (or copolymer) include, but are not limited to, ethylene-based copolymers; conjugated diene-based polymers; or conjugated diene- aromatic vinyl copolymers; and the like.

[0095] The ethylene-based copolymer refers to a copolymer of ethylene and another monomer. Examples of the other monomer copolymerizable with ethylene include, but are not limited to, α-olefins having 3 or more carbon atoms; non-conjugated dienes; vinyl acetate; vinyl alcohol; α,β-unsaturated carboxylic acids or derivatives thereof. Two or more of the above-mentioned monomers can be selected and copolymerized with ethylene.

[0096] Examples of the α-olefin having 3 or more carbon atoms include, but are not limited to, propylene; 1-butene; 1-pentene; or 3-methyl-1-pentene, with propylene or 1-butene being preferable. Examples of the non-conjugated diene include, but are not limited to, 5-methylene-2-norbornene; 5-ethylidene-2-norbornene; 5-vinyl-2-norbornene; 5-propenyl-2-norbornene; 5-isopropenyl-2-norbornene; 5-butenyl-2-norbornene; 5-(2-methyl-2-butenyl)-2-norbornene; 5-(2-ethyl-2-butenyl)-2-norbornene; 5-methyl-5-vinyl norbornene; and the like norbornene compounds; dicyclopentadiene; methyltetrahydroindene; tetrahydroindene; 1,5-cyclooctadiene; 1,4-hexadiene; 6-methyl-1,5-heptadiene; or 11-tridecadiene; and the like, with 5-methylene-2-norbornene; 5-ethylidene-2-norbornene; dicyclopentadiene; or 1,4-hexadiene being preferable. Examples of the α,β-unsaturated carboxylic acid include, but are not limited to, acrylic acid; methacrylic acid; ethylacrylic acid; 2-butenoic acid; maleic acid; fumaric acid; itaconic acid; citraconic acid; or mesaconic acid; and the like. Examples of the derivative of the α,β-unsaturated carboxylic acid include, but are not limited to, alkyl esters; aryl esters; glycerol esters; anhydrides; or imides; and the like of the above-mentioned α,β-unsaturated carboxylic acids.

[0097] The conjugated diene-based polymer refers to a polymer obtained by polymerization of at least one conjugated diene. Examples of the conjugated diene described herein include, but are not limited to, 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,-dimethyl-1,3-butadiene, 1,3-pentadiene, and the like. Two or more of the above conjugated dienes can be copolymerized. In addition, the unsaturated bonds of the polymer can be partially or completely reduced by hydrogenation.

[0098] The conjugated diene-aromatic vinyl copolymer refers to a copolymer of a conjugated diene and an aromatic vinyl, and can be a block copolymer or a random copolymer. Examples of the conjugated diene can be the same as the raw material for producing the conjugated diene-based polymer described above, and 1,3-butadiene and isoprene are preferred. Examples of the aromatic vinyl include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, vinyl naphthalene, and the like, and styrene is preferred. In addition, the unsaturated bonds of the conjugated diene-aromatic vinyl copolymer, except for the double bonds of the aromatic ring, can be partially or completely reduced by hydrogenation.

[0099] The impact-resistant agent can be specifically exemplified by ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / propylene / dicyclopentadiene copolymer, ethylene / propylene / 5-ethylidene-2-norbornene copolymer, unhydrogenated or hydrogenated styrene / isoprene / styrene triblock copolymer, unhydrogenated or hydrogenated styrene / butadiene / styrene triblock copolymer, ethylene / methacrylic acid copolymer or a salt of a part or all of carboxylic acid groups in the copolymer with sodium, lithium, potassium, zinc or calcium, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl acrylate-g-maleic anhydride copolymer (where "g" means grafting, the same applies hereinafter), ethylene / methyl acrylate-g-maleic anhydride copolymer, ethylene / ethyl acrylate-g-maleimide copolymer, ethylene / ethyl acrylate-g-N-phenylmaleimide copolymer or a partially saponified product of the copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / glycidyl methacrylate copolymer, ethylene / methyl methacrylate / glycidyl methacrylate copolymer, ethylene / glycidyl acrylate copolymer, ethylene / vinyl acetate / glycidyl acrylate copolymer, ethylene / glycidyl ether copolymer, ethylene / propylene-g-maleic anhydride copolymer, ethylene / butene-1-g-maleic anhydride copolymer, ethylene / propylene / 1,4-hexadiene-g-maleic anhydride copolymer, ethylene / propylene / dicyclopentadiene-g-maleic anhydride copolymer, ethylene / propylene / 2,5-norbornadiene-g-maleic anhydride copolymer, ethylene / propylene-g-N-phenylmaleimide copolymer, ethylene / butene-1-g-N-phenylmaleimide copolymer, hydrogenated (styrene / butadiene / styrene-g-maleic anhydride) copolymer, hydrogenated (styrene / isoprene / styrene-g-maleic anhydride) copolymer, ethylene / propylene-g-glycidyl methacrylate copolymer, ethylene / butene-1-g-glycidyl methacrylate copolymer, ethylene / propylene / 1,4-hexadiene-g-glycidyl methacrylate copolymer, ethylene / propylene / dicyclopentadiene-g-glycidyl methacrylate copolymer, hydrogenated (styrene / butadiene / styrene-g-glycidyl methacrylate) copolymer, nylon 12 / polytetrahydrofuran copolymer, nylon 12 / polypropylene glycol copolymer, polybutylene terephthalate / polytetrahydrofuran copolymer or polybutylene terephthalate / polypropylene glycol copolymer, and the like. The copolymers are preferably ethylene / methacrylic acid copolymer and a salt of a part or all of carboxylic acid groups in the copolymer with sodium, lithium, potassium, zinc or calcium, ethylene / butene-1-g-maleic anhydride copolymer.

[0100] The polymer other than the end-modified polyamide resin in the above end-modified polyamide resin composition can be added alone or in combination of two or more. The amount of addition is preferably 0 wt% or more and 80 wt% or less (based on 100 wt% of the end-modified polyamide resin composition), and by controlling the amount of addition within the above range, the flowability of the end-modified polyamide resin composition at the time of melting can be made better. The amount of addition is further preferably 60 wt% or less, and still further preferably 50 wt% or less.

[0101] The end-modified polyamide resin composition used in the present application can further contain various additives. For example, there can be mentioned antioxidants and heat stabilizers (hindered phenol-based, hydroquinone-based, phosphite-based, phosphate-based and substituted products thereof, copper halide, iodine compounds, etc.), weathering agents (resorcinol-based, salicylic acid-based, benzotriazole-based, benzophenone-based or steric amine-based, etc.), release agents and lubricants (fatty alcohols, aliphatic amides, aliphatic diamides or diurea or polyethylene wax, etc.), pigments (calcium sulfide, phthalocyanine or carbon black, etc.), dyes (aniline black, etc.), plasticizers (n-octyl p-hydroxybenzoate or N-butylbenzenesulfonamide), antistatic agents (alkyl sulfate anion-based antistatic agents, 4th ammonium salt cation-based antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate or trimethyl glycine-based amphoteric antistatic agents), flame retardants (melamine cyanurate, hydroxides such as magnesium hydroxide and aluminum hydroxide, polyethylene phosphonic acid ammonium, bromine-based flame retardants such as brominated polystyrene, brominated polyphenyl ether, brominated polycarbonate and brominated epoxy resin, or a combination of the above bromine-based flame retardants with antimony trioxide). The above additives can be used alone or in combination of two or more.

[0102] The end-modified polyamide resin of the present application can be formed into a desired shape by any molding method such as injection molding, extrusion molding, blow molding, vacuum molding, melt spinning or film formation. The molded product obtained from the end-modified polyamide resin of the present application and the composition containing the same can be applied to the following examples: resin molded products such as electric / electronic product parts, automobile parts and machine parts, fibers for clothing / industrial fields, films for packaging / electromagnetic recording fields and metal joint bodies. DETAILED DESCRIPTION

[0103] The present application will be further illustrated below with reference to Examples, but the present application is not limited to these Examples.

[0104] The tests involved in the Examples and Comparative Examples are explained as follows:

[0105] (1) Relative viscosity ηr

[0106] The end-modified polyamide resin or polyamide resin homopolymer obtained in each of the examples and comparative examples was precisely weighed and dissolved in 96% concentrated sulfuric acid to prepare a solution having a polyamide resin concentration of 0.01 g / ml, and the relative viscosity was measured at 25°C using an Ubbelohde viscometer.

[0107] (2) Content of end structure represented by Formula II

[0108] The end-modified polyamide resin obtained in each of the examples and comparative examples was dissolved in deuterated concentrated sulfuric acid at a concentration of 50 mg / ml, and1H-NMR measurement was performed using a JEOL ECX 400P manufactured by JEOL Ltd. under conditions of a scan number of 256. 1 1H-NMR measurement. The end-modified polyamide resin obtained in each of the examples and comparative examples was dissolved in deuterated concentrated sulfuric acid at a concentration of 50 mg / ml, and1H-NMR measurement was performed using a JEOL ECX 400P manufactured by JEOL Ltd. under conditions of a scan number of 256. 1

[0109] (3) Boron element content

[0110] The end-modified polyamide resin or polyamide resin homopolymer obtained in each of the examples and comparative examples was weighed, added with sulfuric acid and nitric acid, and then subjected to decomposition under heating with microwaves, followed by dilution with deionized water to obtain a solution. The boron element content of the above solution was measured by ICP emission spectrometry.

[0111] (4) Molecular weight

[0112] The end-modified polyamide resin or polyamide resin homopolymer obtained in each of the examples and comparative examples was dissolved in 4 ml of hexafluoroisopropanol containing 0.0075 N of sodium trifluoroacetate at 2.5 mg, and then filtered with a 0.45 μm filter to measure the number average molecular weight Mn and the weight average molecular weight Mw, under the following measurement conditions.

[0113] Pump: e-Alliance GPC system (manufactured by Waters)

[0114] Detector: differential detector Waters 2414 (manufactured by Waters)

[0115] Chromatographic column: Shodex HFIP-806M (2) + HFIP-LG

[0116] Solvent: hexafluoroisopropanol (to which 0.0075 N of sodium trifluoroacetate was added)

[0117] Flow rate: 0.5 ml / min

[0118] ​Sample injection volume: 0.1 ml

[0119] Temperature: 40℃

[0120] Molecular weight correction: polymethyl methacrylate.

[0121] (5) Amino concentration

[0122] Accurately weigh 100-200 mg of the end-modified polyamide resin or polyamide resin homopolymer obtained in each example and comparative example, dissolve it in 20 ml of phenol / ethanol mixed solution (volume ratio 85 / 15), and then titrate with 0.02 mol / L hydrochloric acid solution.

[0123] (6) Carboxyl concentration

[0124] Accurately weigh 500-600 mg of the end-modified polyamide resin or polyamide resin homopolymer obtained in each example and comparative example, add 20 ml of benzyl alcohol and dissolve at 190 °C, then titrate with 0.02 mol / L potassium hydroxide ethanol solution.

[0125] (7) Melting point

[0126] Using a differential scanning calorimeter (DSC Q2000) from TA Instruments, approximately 3 mg of the end-modified polyamide resin or polyamide resin homopolymer obtained in each example and comparative example was accurately weighed. Under a nitrogen atmosphere, the temperature was increased from 20°C to a temperature 30°C higher than the endothermic peak temperature T0 at a heating rate of 20°C / min, and held at this temperature for 2 min. Then, the temperature was decreased to 20°C at a cooling rate of 20°C / min, held at 20°C for 2 min, and then increased again at a heating rate of 20°C / min to a temperature 30°C higher than T0. The melting point T was then obtained. m T m This is the temperature corresponding to the peak tip of the endothermic peak during the secondary heating process.

[0127] (8) Melt viscosity

[0128] The end-modified polyamide resins or polyamide resin homopolymers obtained in the various examples and comparative examples were dried in a vacuum drying oven at 80°C for more than 12 hours. They were then hot-pressed into films (0.7 mm thick) using a film press and cut into 25 mm diameter discs. The melt viscosity was determined using a rotational rheometer (Antonpaar, MCR302, φ25 parallel plates) using the following method: The samples were melted at 280°C for 5 minutes under a nitrogen atmosphere; the parallel plate spacing was 0.5 mm; the vibration mode was used for measurement; the frequency was 0.5–6.88 Hz; 50 points were measured (0.5 minutes); the amplitude was 1%. The complex viscosity measured at a frequency of 1 Hz was used as the melt viscosity.

[0129] (9) Foaming state of the discharged polymer

[0130] After the polymerization of each example and comparative example was completed, nitrogen was introduced into the polymerizer to pressurize the polymerizer to 0.05-0.1 MPa, and the polymer in the polymerizer was discharged from the discharge valve at the bottom of the polymerizer. The discharged polymer strand was observed and recorded for its state and pelletizing.

[0131] O: The discharged polymer strand had no holes inside and a smooth surface, and could be continuously and stably pelletized.

[0132] Δ: The discharged polymer strand had holes inside and a basically smooth surface, and could be pelletized but occasionally broke.

[0133] X: The discharged polymer strand had a large number of holes inside or even was hollow, had a rough surface, and was extremely easy to break, and could not be pelletized.

[0134] The raw materials used in the examples and comparative examples were as follows:

[0135] Hexanediamine: Aladdin Reagent (Shanghai) Co., Ltd.

[0136] Adipic acid: Alfa Aesar

[0137] Compound for end modification shown in Formula I: Huntsman

[0138]

[0139] Boric acid: Sigma-Aldrich

[0140] Sodium hypophosphite: Sigma-Aldrich

[0141] Example 1

[0142] 13.79 kg of hexanediamine, 16.71 kg of adipic acid, 569.4 g of compound for end modification shown in Formula I, 0.9 kg of boric acid, and 0.9 kg of sodium hypophosphite were added into a polymerizer, and the mixture was polymerized under the conditions of a polymerization temperature of 200°C, a polymerization pressure of 0.1 MPa, and a polymerization time of 4 hours. M-1000 (Mn = 1000), 1.5 g of boric acid were dissolved in 23 kg of deionized water and charged into a reaction vessel. The reaction vessel was closed and replaced with nitrogen three times. The temperature of the heater of the reaction vessel was set to 300°C and heating was started. When the pressure in the reaction vessel reached 1.75 MPa, the water vapor in the reaction vessel was released through a vent valve while the pressure in the reaction vessel was maintained at 1.75 MPa until the temperature in the reaction vessel reached 260°C. When the temperature in the reaction vessel reached 260°C, the pressure in the reaction vessel was gradually reduced from 1.75 MPa to atmospheric pressure in 1 hour (the temperature in the reaction vessel was 275°C when atmospheric pressure was reached). After the pressure was reduced to atmospheric pressure, the pressure in the reaction vessel was reduced to -0.05 MPa through a pressure reduction line, and the molten polymerization was carried out at a vacuum of -0.05 MPa for 100 minutes (the maximum temperature reached was 263°C), and a terminal-modified nylon 66 was obtained. The properties of the terminal-modified nylon 66 obtained by the above method are shown in Table 1.

[0143] Examples 2 to 8, Comparative Examples 1 to 4

[0144] Except that the raw materials and the amounts of addition and the pressure reduction time after the pressure in the reaction vessel reached atmospheric pressure were changed as shown in Table 1, the other operations were the same as in Example 1. The properties of the terminal-modified nylon 66 obtained are shown in Table 1.

[0145] Table 1

[0146]

[0147] Examples 1 to 8, Comparative Example 1, since the terminal-modified compound represented by Formula I was added, the melt viscosity of the terminal-modified polyamide resin obtained was lower than that of the polyamide homopolymer which was not terminal-modified in Comparative Example 1.

[0148] In addition, since a certain amount of the boric acid compound was also added in Examples 1 to 8, the polymerization time was shorter to achieve the same relative viscosity level of the polyamide polymerization product, the foaming of the polymer discharged was improved, and the carboxyl group concentration of the polymer obtained was lower, compared with the polyamide homopolymerization system in which no boric acid compound was added in Comparative Example 1, the terminal-modified polyamide polymerization system in which no boric acid compound was added in Comparative Example 2, or the terminal-modified polyamide polymerization system in which the sodium hypophosphite catalyst commonly used for polyamide polymerization was added in Comparative Example 3. In Comparative Example 4, the amount of the boric acid compound added was too high, and the polymerization could not be carried out.

[0149] Examples 9 to 12, Comparative Example 5

[0150] Except that the raw materials and the amounts of addition and the pressure reduction time after the pressure in the reaction vessel reached atmospheric pressure were changed as shown in Table 2, the other operations were the same as in Example 1. The properties of the terminal-modified nylon 66 obtained are shown in Table 2.

[0151] Table 2

[0152]

[0153] As can be seen from Examples 9 to 12, the melt viscosity of the polymer tends to decrease as the amount of the modifying compound added to the terminal of Formula I increases. In Comparative Example 5, the amount of the modifying compound added to the terminal of Formula I is too high, the foaming of the extruded polymer cannot be suppressed, and the melting point of the polymer decreases.

[0154] Examples 13 to 19

[0155] Except that the raw materials and the amounts thereof and the time of the polymerization under reduced pressure after the pressure in the kettle reaches the normal pressure are changed as shown in Table 3, the other operations are the same as in Example 1. The properties of the terminal-modified nylon 66 obtained are shown in Table 3.

[0156] Table 3

[0157]

[0158] In Examples 13 to 19, the boronic acid compound is added, and as the molar ratio of the total amino groups / the total carboxyl groups of the raw materials added gradually increases from 1.002 in Example 13 to 1.100 in Example 19, the carboxyl group concentration in the polymer tends to decrease, and the time of the polymerization under reduced pressure required to reach the same relative viscosity level can be controlled to be within 50 minutes.

Claims

1. A method for preparing an end-modified polyamide resin, characterized in that: Polymerization was carried out in the presence of polyamide monomers, the end-modifying compound shown in Formula I, and a boric acid compound. X-(R1-O)n-R2 Formula I In Formula I, n ranges from 2 to 100, each R1 may be the same or different, and is an alkylene group with 2 to 10 carbon atoms; R2 is an alkyl group with 1 to 30 carbon atoms; and X is selected from NH2-, NH(CH3)-, HO-, HOOC-, O=C=N-, and... One or more of the following; The polyamide monomer is 100 parts by weight, the amount of the end-modifying compound shown in Formula I is 0.05 to 25 parts by weight, and the amount of the boric acid compound is 0.005 to 1.0 parts by weight.

2. The method for preparing the end-modified polyamide resin according to claim 1, characterized in that: The end-modifying compound shown in Formula I and the boric acid compound can be added at any time before the end of polymerization.

3. The method for preparing the end-modified polyamide resin according to claim 1, characterized in that: The boric acid compound is selected from one or more of boric acid, borates, and organoboronic acid compounds.

4. The method for preparing the end-modified polyamide resin according to claim 1, characterized in that: The polyamide monomer is selected from one or more of the following: a combination of a diamine having 2 to 20 carbon atoms and a diacid having 2 to 20 carbon atoms, an amino acid having 4 to 20 carbon atoms, a lactam having 4 to 20 carbon atoms, a mixture of the above polyamide monomers, or a salt thereof.

5. The method for preparing the end-modified polyamide resin according to claim 1, characterized in that: The amount of the polyamide monomer and the end-modifying compound shown in Formula I added satisfies the relationship that the molar ratio of total amino groups to total carboxyl groups is more than 1.010 and less than 1.

10.

6. The method for preparing the end-modified polyamide resin according to claim 5, characterized in that: The amount of the polyamide monomer and the end-modifying compound shown in Formula I added satisfies the relationship that the molar ratio of total amino groups to total carboxyl groups is more than 1.020 and less than 1.

050.

7. The method for preparing the end-modified polyamide resin according to claim 1, characterized in that: With 100 parts by weight of the polyamide monomer, 5 to 900 parts by weight of water are further added.

8. An end-modified polyamide resin, characterized in that: The end-modified polyamide resin has the end structure shown in Formula II and the element boron. -Y-(R1-O)n-R2 Formula II In Formula II, n ranges from 2 to 100, each R1 may be the same or different, and is an alkylene group with 2 to 10 carbon atoms; R2 is an alkyl group with 1 to 30 carbon atoms; and Y is one or more selected from -NH-, -N(CH3)-, -O-, -C(=O)-, -C(=O)-NH-, -NH-C(=O)-NH- and -CH2-CH(OH)-. The content of the end structure shown in Formula II in the end-modified polyamide resin is 0.05 to 25 wt% of the total weight of the end-modified polyamide resin. The boron content in the end-modified polyamide resin is 10 to 2000 ppm of the total weight of the end-modified polyamide resin.

9. The end-modified polyamide resin according to claim 8, characterized in that: In the end structure shown in Formula II, n ranges from 16 to 100.

10. The end-modified polyamide resin according to claim 8, characterized in that: In the terminal structure shown in Formula II, each R1 may be the same or different, and is at least one of -CH2-CH2-, -CH2-CH2-CH2-, and -CH(CH3)-CH2-.

11. The end-modified polyamide resin according to claim 8, characterized in that: When the end-modified polyamide resin is prepared into a solution with a concentration of 0.01 g / ml using 96 wt% sulfuric acid as a solvent, the relative viscosity ηr measured at 25°C is 1.1 to 4.

0.

12. The end-modified polyamide resin according to claim 8, characterized in that: The weight-average molecular weight (Mw) of the end-modified polyamide resin, as determined by gel permeation chromatography, ranges from 10,000 to 400,000.

13. The end-modified polyamide resin according to claim 8, characterized in that: The melting point of the end-modified polyamide resin is above 215°C.

14. The end-modified polyamide resin according to claim 8, characterized in that: The amino concentration in the terminal modified polyamide resin is 105–400 mol / t.

15. The end-modified polyamide resin according to claim 8, characterized in that: The carboxyl group concentration in the terminal modified polyamide resin is below 100 mol / t.

16. The end-modified polyamide resin according to claim 8, characterized in that: The ratio of amino group concentration to carboxyl group concentration in the end-modified polyamide resin is 4.0 or higher and 50 or lower.

17. An end-modified polyamide resin composition comprising the end-modified polyamide resin according to any one of claims 8 to 16.

18. A molded article comprising the end-modified polyamide resin according to any one of claims 8 to 16 or the end-modified polyamide resin composition according to claim 17.

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