Polyurea, polyurea composition, and molded article

Abstract

Provided is a polyurea which has a number-average molecular weight Mn of 6,000-50,000, and in which the ratio (ηEa / ηEb) of the shear viscosity ηEa (Pa･s) at a shear rate of 0.1 (1 / s), measured at 20°C above melting point, to the shear viscosity ηEb (Pa･s) at a shear rate of 10 (1 / s), measured at 20°C above melting point, is 1.1-10.0.

Description

Polyurea, as well as polyurea compositions and molded articles

[0001] The present invention relates to polyurea, as well as polyurea compositions and molded articles, and more particularly to polyurea having high mechanical properties and being difficult to color, as well as polyurea compositions and molded articles containing said polyurea.

[0002] Polyureas possess properties such as heat resistance, high mechanical strength (mechanical properties), and chemical corrosion resistance, and are used in injection molded products, fibers, coatings, films, sheets, etc. The above-mentioned properties of polyureas are greatly influenced by their molecular weight, structure, etc.

[0003] As an example of polyurea, a polyurea obtained by polymerizing a diamine compound with carbon dioxide under conditions of a pressure of 1 to 10 MPa and a temperature of 160 to 260°C has been reported (see Patent Document 1).

[0004] Japanese Patent Publication No. 2012-107095

[0005] However, the polyurea described in Patent Document 1 did not necessarily exhibit sufficient discoloration when it possessed sufficient mechanical properties.

[0006] This invention has been made in view of the above circumstances, and aims to provide a polyurea having high mechanical properties and being difficult to color, as well as a polyurea composition containing the polyurea and a molded article.

[0007] The inventors of the present invention conducted diligent research to solve the above problems and found that polyureas with a number-average molecular weight Mn and a ratio (ηEa / ηEb) within a predetermined range have high mechanical properties and are less prone to discoloration, thus completing the present invention. The above "ηEa" refers to the shear viscosity (Pa·s) of polyurea at a shear rate of 0.1 (1 / s) measured at the melting point of polyurea + 20°C, and the above "ηEb" refers to the shear viscosity (Pa·s) of polyurea at a shear rate of 10 (1 / s) measured at the melting point of polyurea + 20°C.

[0008] In other words, the present invention is as follows: [1]

[10] [1] A polyurea having a number average molecular weight Mn of 6,000 to 50,000, and a ratio (ηEa / ηEb) of the shear viscosity ηEa (Pa·s) at a shear rate of 0.1 (1 / s) measured at the melting point + 20°C to the shear viscosity ηEb (Pa·s) at a shear rate of 10 (1 / s) measured at the melting point + 20°C to 1.1 to 10.0. [2] In the differential molecular weight distribution curve of the number average molecular weight of the polyurea, when the intensity at the peak top molecular weight M(t) is set to 1, the molecular weight on the high molecular weight side at the point where the intensity becomes 1 / 2 is defined as Mh(t) １／２ In this case, the Mh(t) is the area of ​​the entire region of the differential molecular weight distribution curve. １／２ [1] The polyurea described above, wherein the area ratio of the high molecular weight region above 5 to 20%. [3] The polyurea described above, wherein the molecular weight distribution Mw / Mn is 1.0 to 3.0. [4] The polyurea described above, wherein the carbonyl group in the urea bond is derived from a urea-based compound. [5] The polyurea described above, wherein the polyurea contains an aliphatic diamine unit, and the average number of carbon atoms in the main chain of the aliphatic diamine unit is 8.5 or more. [6] The polyurea described above, wherein the number average molecular weight and amine value satisfy the following formula (1). Formula (1): 2.0 ≤ (number average molecular weight × amine value [μmol / g]) / 10 ６ ≤4.0 [7] A polyurea according to any one of [1] to [6] above, having a melting point of 120 to 280°C. [8] A polyurea composition comprising the polyurea according to any one of [1] to [7] above and a nickel element, wherein the content of the nickel element in the polyurea composition is 0.05 to 100 ppm by mass. [9] A polyurea composition comprising the polyurea according to any one of [1] to [7] above and a sodium element, wherein the content of the sodium element in the polyurea composition is 30 to 3,000 ppm by mass.

[10] A molded article comprising the polyurea according to any one of [1] to [7] above.

[0009] According to the present invention, it is possible to provide a polyurea having high mechanical properties and being difficult to color, as well as a polyurea composition containing the polyurea and a molded article.

[0010] Figure 1 is a schematic diagram illustrating the high molecular weight region in the differential molecular weight distribution curve.

[0011] The following description is based on an example of an embodiment of the present invention. However, the embodiments shown below are illustrative examples for realizing the technical concept of the present invention, and the present invention is not limited to the following description. In this specification, preferred provisions can be adopted at will, and combinations of preferred provisions can be said to be more preferred. In this specification, the description "XX to YY" means "XX or more and YY or less". In this specification, the lower and upper limits of preferred numerical ranges (for example, ranges of content, etc.) described in steps can be combined independently. For example, from the description "preferably 10 to 90, more preferably 30 to 60", the "preferred lower limit (10)" and the "more preferred upper limit (60)" can be combined to get "10 to 60". Also, in numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with the values ​​shown in the examples. In this specification, "structural unit" means "a unit that constitutes a polymer". In this specification, "film" usually means a film with a thickness of 400 μm or less that can be wound into a roll. On the other hand, "sheet" usually refers to a material with a thickness of more than 400 μm that cannot be rolled up. In this specification, "number of carbon atoms in the main chain" in the average number of carbon atoms in the main chain of an aliphatic diamine unit means the number of carbon atoms that make up the main chain of polyurea in an aliphatic diamine, that is, the number of carbon atoms between terminal amino groups in an aliphatic diamine.

[0012] [Polyurea] The polyurea of ​​the embodiment of the present invention (hereinafter sometimes referred to as "this embodiment") has a number average molecular weight Mn of 6,000 to 50,000, and the ratio (ηEa / ηEb) of the shear viscosity ηEa (Pa·s) at a shear rate of 0.1 (1 / s) measured at the melting point + 20°C to the shear viscosity ηEb (Pa·s) at a shear rate of 10 (1 / s) measured at the melting point + 20°C is 1.1 to 10.0. By having such a configuration, a polyurea with high mechanical properties and that is less prone to discoloration can be obtained. That is, the polyurea of ​​this embodiment is not particularly limited as long as the number average molecular weight Mn and the ratio (ηEa / ηEb) are within a predetermined range, and may be mixed with nickel elements, sodium elements, etc. as needed to form a polyurea composition, or it may not be formed into a polyurea composition. Although the detailed mechanism by which polyureas with a number-average molecular weight Mn and ratio (ηEa / ηEb) within a predetermined range possess high mechanical properties and are less prone to discoloration is unknown, it is speculated as follows: As the number-average molecular weight Mn of polyureas increases, the mechanical properties tend to improve. Therefore, in order to obtain polyureas with excellent mechanical properties, it is desirable that the number-average molecular weight Mn be above a certain level. When obtaining polyureas by polycondensation reaction, if the proportion of urea is high relative to the diamine and the reaction temperature is high, biuret bonds are formed between the molecular chains of the polyurea, producing a high molecular weight product, and the above-mentioned shear viscosity ηEa increases (the above-mentioned shear viscosity ηEb does not increase as much as the shear viscosity ηEa). Furthermore, when obtaining polyureas with a large number-average molecular weight Mn, it is thought that the above-mentioned biuret bonds are more likely to form from the viewpoint of reaction time, reaction conditions, etc., and therefore the above-mentioned high molecular weight product is more likely to be produced. It is also speculated that the more biuret bonds there are, the greater the discoloration. Based on the above, we hypothesize that by setting the number-average molecular weight Mn and ratio (ηEa / ηEb) of the polyurea within a predetermined range, it is possible to provide a polyurea with high mechanical properties and resistance to discoloration, as well as a polyurea composition and molded articles containing the said polyurea.

[0013] The ratio of polyurea (ηEa / ηEb) is not particularly limited as long as it is between 1.1 and 10.0, but is preferably between 1.3 and 8.5, more preferably between 1.5 and 7.0, and most preferably between 1.7 and 6.0. If it is above the lower limit of the above range, it becomes easier to melt-mold, and if it is below the upper limit of the above range, the yellowness (YI) of the polyurea tends to be low, and the color tone of the molded article tends to be good. The ratio (ηEa / ηEb) can be determined by the measurement method described in the examples.

[0014] The number-average molecular weight Mn of the polyurea is not particularly limited as long as it is between 6,000 and 50,000, but from the viewpoint of achieving both mechanical properties and moldability, it is preferably between 7,000 and 35,000, more preferably between 7,500 and 30,000, and particularly preferably between 8,000 and 20,000. The number-average molecular weight Mn of the polyurea can be determined by the measurement method described in the examples.

[0015] There are no particular restrictions on the weight-average molecular weight Mw of the polyurea, but from the viewpoint of achieving both mechanical properties and moldability, it is preferably 10,000 to 70,000, more preferably 12,000 to 50,000, and particularly preferably 13,000 to 40,000. The weight-average molecular weight Mw of the polyurea can be determined by the measurement method described in the examples.

[0016] There are no particular restrictions on the molecular weight distribution Mw / Mn of the polyurea, but from the viewpoint of balancing ease of manufacturing (difficulty of controlling molecular weight distribution) and moldability, it is preferably 1.0 to 3.0, more preferably 1.3 to 2.5, and particularly preferably 1.5 to 2.0. The molecular weight distribution Mw / Mn of the polyurea can be calculated using the number average molecular weight Mn and weight average molecular weight Mw obtained by the measurement method described in the examples.

[0017] In the differential molecular weight distribution curve of the number-average molecular weight of polyurea, when the intensity at the peak-top molecular weight M(t) is set to 1, the molecular weight on the higher molecular weight side at the point where the intensity becomes 1 / 2 is defined as Mh(t). １／２ In this case, the Mh(t) is the area of ​​the entire region of the differential molecular weight distribution curve. １／２There are no particular restrictions on the proportion of the area of ​​the high molecular weight region (hereinafter sometimes referred to as the "proportion of high molecular weight components"), but it is preferably 5 to 20%, more preferably 7 to 18%, and particularly preferably 10 to 16%. If it is above the lower limit of the above range, it becomes easier to melt mold, and if it is below the upper limit of the above range, the yellowness (YI) is low and the design of the molded article tends to be good. The proportion of high molecular weight components can be determined by the measurement method described in the examples.

[0018] As long as the polyurea has a urea bond (-NH-C(=O)-NH-), there are no particular restrictions, and it may or may not contain other bonds besides the urea bond, as long as it does not impair the effects of the present invention. From the viewpoint of thermal stability, it is preferable that the polyurea does not contain any bonds other than carbon-carbon bonds, carbon-hydrogen bonds, and urea bonds. There are no particular restrictions on the other bonds besides the urea bond, and examples include urethane bonds (-NH-C(=O)-O-), amide bonds (-NH-C(=O)-), etc. These may be used individually or in combination of two or more.

[0019] The carbonyl group (-C(=O)-) in the urea bond of polyurea is not particularly limited and may be derived from urea compounds, isocyanate compounds, carbon dioxide, carbonate compounds, or phosgene compounds. Among these, it is preferable that it be derived from urea compounds from the viewpoint of productivity, raw material toxicity, and availability.

[0020] There are no particular restrictions on the urea-based compound, and examples include urea, thiourea, methylenediurea, ethylenediurea, and other urea derivatives. These may be used individually or in combination of two or more. Among these, urea is preferred from the viewpoint of productivity and availability.

[0021] There are no particular restrictions on the monomer units that constitute the urea bond (i.e., the monomer units that constitute the polyurea), and examples include urea compounds, isocyanate compounds, carbon dioxide, carbonate compounds, phosgene compounds, diamines, and their derivatives. These may be used individually or in combination of two or more. Among these, from the viewpoint of moldability, productivity, and availability, combinations of diamine and urea compounds, combinations of diamine and isocyanate compounds, and combinations of diamine and carbon dioxide are preferred, with combinations of diamine and urea compounds being more preferred.

[0022] There are no particular restrictions on the total amount of diamine-derived structural units (hereinafter sometimes referred to as "diamine units") and urea-based compound-derived structural units (hereinafter sometimes referred to as "urea-based compound units") in the monomer units constituting the polyurea. However, from the viewpoint of thermal stability, it is preferably 80 mol% or more, more preferably 90 mol% or more, and particularly preferably 100 mol% of the total amount of monomer units constituting the polyurea.

[0023] <Diamines> There are no particular restrictions on the diamines that constitute the diamine units in polyureas. Examples include aliphatic diamines, aromatic diamines, alicyclic diamines, and ether diamines. These may be used individually or in combination of two or more. Note that diamines may include urea (H ２ NC(=O)-NH ２Urea-based compounds such as ) are not included. By appropriately selecting the type of diamine, the melting point, mechanical properties, chemical resistance, etc. of the polyurea can be controlled. Among these, aliphatic diamines are preferred from the viewpoint of achieving a balance between moldability, mechanical properties, and chemical resistance. When the polyurea contains structural units derived from aliphatic diamines (hereinafter sometimes referred to as "aliphatic diamine units"), there are no particular restrictions on the average number of carbon atoms in the main chain of the aliphatic diamine units, but it is preferably 8.5 or more, more preferably 8.5 to 12, and particularly preferably 8.5 to 10. If it is above the lower limit of the above range, it becomes easier to reduce the discoloration of the polyurea during processing, and if it is below the upper limit of the above range, the melting point of the polyurea increases and the heat resistance tends to improve. The average number of carbon atoms in the main chain of the aliphatic diamine units can be determined by the measurement method described in the examples.

[0024] (Aliphatic Diamines) Aliphatic diamines refer to diamines that do not include aromatic diamines, alicyclic diamines, and ether diamines, as described later, and that contain only aliphatic hydrocarbon groups without a cyclic structure. There are no particular restrictions on aliphatic diamines; they may contain only saturated hydrocarbon groups or unsaturated hydrocarbon groups. Among these, diamines that do not contain unsaturated hydrocarbon groups are preferred from the viewpoint of preventing discoloration and deterioration of polyureas. There are no particular restrictions on the aliphatic diamines, and examples include linear aliphatic diamines such as 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, and 1,18-octadecanediamine; and 2-methyl-1,5-pentane Examples include diamines, branched aliphatic diamines such as 2-methyl-1,6-hexanediamine, 2-methyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 2-methyl-1,9-nonanediamine, 2-methyl-1,10-decanediamine, 2-methyl-1,11-undecanediamine, 2-methyl-1,12-dodecanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine, 2,2,4-trimethyl-1,8-octanediamine, and 2,4,4-trimethyl-1,8-octanediamine. These may be used individually or in combination of two or more. Among these, from the viewpoint of achieving both mechanical properties and moldability, aliphatic diamines having 3 to 18 carbon atoms are preferred, aliphatic diamines having 5 to 15 carbon atoms are more preferred, aliphatic diamines having 7 to 12 carbon atoms are even more preferred, and aliphatic diamines having 9 carbon atoms are particularly preferred.

[0025] Linear aliphatic diamines and branched aliphatic diamines may be used in combination, one or more of each. There are no particular restrictions on the content of structural units derived from linear aliphatic diamines (hereinafter sometimes referred to as "linear aliphatic diamine units") in the monomer units constituting the polyurea. However, from the viewpoint of achieving a balance between moldability, mechanical properties, and chemical resistance, the content is preferably 50 mol% or more, more preferably 65 mol% or more, and particularly preferably 80 mol% or more, per 100 mol% of aliphatic diamine units. The content of linear aliphatic diamine units can be calculated by the charging ratio when manufacturing the polyurea. If the charging ratio when manufacturing the polyurea is unknown, １ It can be calculated from the integral ratio of the H-NMR spectrum. There are no particular restrictions on the combination of linear aliphatic diamine and branched aliphatic diamine, but (i) a combination of one of 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine and one of 2-methyl-1,5-pentanediamine, 2-methyl-1,6-hexanediamine, 2-methyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 2-methyl-1,9-nonanediamine, 2-methyl-1,10-decanediamine, and 2-methyl-1,11-undecanediamine is preferred, and (ii) one of 1,8-octanediamine, 1,9-nonanediamine, and 2 A combination with one of the following is more preferred: (iii) a combination of 1,9-nonanediamine and 2-methyl-1,8-octanediamine, 1,10-decanediamine and 2-methyl-1,5-pentanediamine, and 1,10-decanediamine and 2-methyl-1,6-hexanediamine; (iv) a combination of 1,9-nonanediamine and 2-methyl-1,8-octanediamine, and 1,10-decanediamine and 2-methyl-1,5-pentanediamine.

[0026] (Aromatic Diamines) Aromatic diamines refer to diamines having aromatic rings such as benzene rings and naphthalene rings. There are no particular restrictions on aromatic diamines, and examples include phenylenediamine, diaminodiphenyl ether, xylylenediamine, biphenylenediamine, dichlorobenzidine, dimethylbenzidine, diaminodiphenylmethane, and naphthalenediamine. These may be used individually or in combination of two or more. Among these, xylylenediamine is preferred from the viewpoint of availability, and metaxylylenediamine is more preferred.

[0027] (Alicyclic Diamines) Alicyclic diamines refer to diamines having an aliphatic cyclic structure, such as cyclopentane and cyclohexane. There are no particular restrictions on alicyclic diamines, and examples include 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, and 2,5-bisaminomethylfuran. These may be used individually or in combination of two or more.

[0028] (Polyether diamine) Polyether diamine means a compound that contains an ether bond and does not fall under the above-mentioned aliphatic diamine, aromatic diamine, or alicyclic diamine. There is no particular limitation on the polyether diamine. For example, polyether diamines include those obtained by introducing amino groups to both ends of glycols such as polyethylene glycol (PEG), polypropylene glycol (PPG), polytrimethylene ether glycol (PO3G), poly(oxybutylene) glycol, polytetramethylene ether glycol (PTMG), poly(3-methyltetrahydrofuran) (poly(3MeTHF)), etc., poly(3-alkyltetrahydrofuran); those obtained by introducing amino groups to both ends of copolymers of the above-mentioned glycols; and the like. These may be used alone or in combination of two or more kinds.

[0029] In the polyurea of the present invention, two or more kinds of diamines may be mixed and used. There is no particular limitation on the combination of diamines. For example, combinations include 1,9-nonanediamine and 2-methyl-1,8-octanediamine, 1,10-decanediamine and 2-methyl-1,5-pentanediamine, 1,10-decanediamine and metaxylylenediamine, 1,10-decanediamine and 1,3-bis(aminomethyl)cyclohexane, 1,9-nonanediamine and 2-methyl-1,8-octanediamine and 1,10-decanediamine, and the like. However, the present invention is not limited to these combinations. The proportion of aliphatic diamine units relative to the total diamine units is not particularly limited, but from the viewpoint of coexistence of molding processability, mechanical properties, heat resistance, and chemical resistance, it is preferably 50 to 100 mol%, more preferably 70 to 100 mol%, and particularly preferably 85 to 100 mol%. The proportion of aliphatic diamine units can be calculated based on the charging ratio when producing the polyurea. When the charging ratio when producing the polyurea is unknown, １ it can be calculated from the integration ratio of the H-NMR spectrum.

[0030] There are no particular restrictions on the total ratio of structural units derived from aromatic diamines, alicyclic diamines, and ether diamines to the total number of diamine units. However, from the viewpoint of achieving a balance between moldability, mechanical properties, heat resistance, and chemical resistance, it is preferably 50 mol% or less, more preferably 30 mol% or less, and particularly preferably 15 mol% or less. The total ratio of structural units derived from aromatic diamines, alicyclic diamines, and ether diamines can be calculated using the charging ratio when producing polyurea. If the charging ratio when producing polyurea is unknown, １ It can be calculated from the integral ratio of the 1H-NMR spectrum. When using a mixture of two or more diamines, there are no particular restrictions on the arrangement order of the diamine units; it can be random, block, alternating, or any other arrangement.

[0031] There are no particular restrictions on the melting point of polyurea, but from the viewpoint of achieving both moldability and heat resistance, it is preferably 120 to 280°C, more preferably 140 to 270°C, even more preferably 160 to 240°C, and most preferably 180 to 220°C. The melting point of polyurea can be determined by the measurement method described in the examples.

[0032] The amine value of polyurea can be adjusted by the content of terminal amino groups, and there is a correlation between the number of terminal groups and the number-average molecular weight. That is, polyurea with a small number-average molecular weight exhibits a high amine value, and polyurea with a large number-average molecular weight exhibits a low amine value. Furthermore, even with similar molecular weights, the amine value of polyurea can be adjusted by the charging ratio of the raw materials. Specifically, by making the charging molar ratio of diamine to urea diamine-rich, polyurea with a high amine value can be obtained. There are no particular restrictions on the amine value of polyurea, but from the viewpoint of mechanical properties and moldability, it is preferably 150 μmol / g or more, more preferably 150 to 500 μmol / g, even more preferably 160 to 400 μmol / g, and particularly preferably 170 to 350 μmol / g. If it is above the lower limit of the above range, it is easier to improve viscosity stability during melt molding, and if it is below the upper limit of the above range, it is easier to suppress the deficiency of mechanical properties due to a small number-average molecular weight. The amine value (amino group content) of polyurea can be measured by the method described in the examples.

[0033] There are no particular restrictions on the number-average molecular weight and amine value of the polyurea, but from the viewpoint of achieving a high level of both mechanical properties and moldability, it is preferable that the following formula (1) is satisfied, more preferably that the following formula (1-1) is satisfied, even more preferably that the following formula (1-2) is satisfied, and particularly preferably that the following formula (1-3) is satisfied. Formula (1): 2.0 ≤ (number-average molecular weight × amine value [μmol / g]) / 10 ６ ≤4.0 Equation (1-1): 2.0 ≤ (number-average molecular weight × amine value [μmol / g]) / 10 ６ ≤3.5 Equation (1-2): 2.0 ≤ (number-average molecular weight × amine value [μmol / g]) / 10 ６ ≤3.2 Equation (1-3): 2.0 ≤ (number-average molecular weight × amine value [μmol / g]) / 10 ６When the number average molecular weight and amine value in the polyurea satisfy the formula (1), the polyurea can achieve both high mechanical properties and high molding processability. Although the detailed mechanism is unknown, it is speculated as follows. Generally, polyurea has poor viscosity stability in the molten state during melt molding or the like. This is due to the thickening caused by the crosslinking reaction between the isocyanate groups generated from the terminal urea groups of the polyurea by heating or the like and the urea bonds in the polyurea main chain, and the thickening becomes more prominent as the molecular weight increases. However, when the polyurea satisfies the formula (1), amino groups with higher reactivity to isocyanate than urea bonds are present in a high concentration per molecule of the polyurea, and the above crosslinking reaction is suppressed. In addition, when the polyurea satisfies the formula (1), the amount of terminal urea groups of the polyurea is reduced, and the possible isocyanate groups are reduced. From the above, it is speculated that when the number average molecular weight and amine value in the polyurea satisfy the formula (1), the polyurea can achieve both high mechanical properties and high molding processability.

[0034] <Manufacturing method of polyurea> There is no particular limitation on the manufacturing method of polyurea. For example, urea and diamine are heated and reacted, preferably with an excess of diamine, in an inert gas atmosphere, with or without being dissolved in a solvent such as water, phenol, m-cresol, etc., and then, if the solvent is present, it can be obtained by a polycondensation reaction in which the reaction is completed while distilling off the solvent.

[0035] Regarding the temperature of the polycondensation reaction, first, it is heated at a relatively low temperature of 80 to 130 °C to generate a low-degree condensate and the generation of ammonia temporarily stops, and then the temperature is gradually raised. The generation of ammonia becomes active again at 140 to 190 °C. Control the temperature at this time, distill off the solvent if it is present, and raise the temperature again. After the deammoniation reaction by heating is completed, if the heating reaction is continued at a temperature of 200 to 280 °C under reduced pressure, the polycondensation reaction proceeds smoothly and a linear copolymer can be obtained.

[0036] In the polycondensation reaction, especially when no solvent is added, it is desirable to suppress solidification due to excessive growth during the temperature rise process. In the deammoniation reaction at 140 to 190 °C, the melting point of the low-degree condensate rises as the growth progresses.

[0037] When the melting point of the low-degree condensate is equal to or higher than the reaction temperature, solidification of the reaction system progresses and it becomes impossible to stir. Therefore, in the polycondensation reaction of polyurea where the by-product distillate is ammonia gas, unlike other polycondensation reactants such as polyamides and polyesters, the reaction equilibrium constant is large, and it can be said that in particular, suppressing excessive growth of the low-degree condensate is important.

[0038] There are no particular restrictions on the method for controlling the polycondensation reaction. For example, known methods such as controlling the ratio of raw material monomers, suppressing the distillation of by-products, and using low-reactive monomers such as carbon dioxide can be mentioned. These may be used alone or in combination of two or more. Among these, the method of controlling the ratio of raw material monomers is preferable in that suppressing the distillation of by-products and using low-reactive monomers require large-scale pressure-resistant equipment or catalysts. In this specification, "raw material monomer", "low-reactive monomer", "charged monomer", and "monomer" mean compounds that are monomer units constituting polyurea, and examples include diamines, urea-based compounds, carbon dioxide, etc.

[0039] The molar ratio (diamine / urea) of the charged monomer is not particularly limited, but from the viewpoints of the growth suppression effect and the quality stability in the high molecular weightization process described later, it is preferably 1.20 to 1.60, more preferably 1.30 to 1.60, and particularly preferably 1.30 to 1.40. When it is at or above the lower limit value of the above range, it is easy to improve the growth suppression effect, and when it is at or below the upper limit value of the above range, it is easy to improve the quality stability in the high molecular weightization process described later. Also, if the above range is 1.20 to 1.60, it becomes easy to suppress excessive growth of the low-degree condensate and the quality in the high molecular weightization process described later is likely to be stable. That is, by setting the molar ratio (diamine / urea) of the charged monomer to 1.20 to 1.60, heating at a relatively low temperature of 80 to 130 °C to generate a low-degree condensate and temporarily stop the generation of ammonia, then raising the temperature to 140 to 190 °C, and after completing the deammoniation reaction by heating, raising the temperature to a temperature of 200 to 280 °C, smooth polymerization becomes possible without solidification of the reaction system.

[0040] (Addition of urea: High molecular weight after heating) When the molar ratio (diamine / urea) of the charged monomer is 1.20 to 1.60, the obtained polyurea has a low molecular weight, and it is preferable to further increase its molecular weight by a reaction at a temperature of 200 to 280°C in order to further improve its mechanical properties. There are no particular restrictions on the method of increasing molecular weight, and examples include the addition of raw materials, the addition of chain extenders, the removal of excess monomers by vacuum distillation, and the solid-phase polymerization of the obtained resin. These may be used individually or in combination of two or more. Among these, from the viewpoint of production yield and process simplification, the methods of adding raw materials and chain extenders are preferred, and the addition of urea is more preferred.

[0041] -Method for adding urea- There are no particular restrictions on the method for adding urea. For example, a urea solution dissolved in a solvent inert to the polycondensation reaction may be added, or it may be added as a solid. Among these, the method of adding urea as a solid is preferred from the viewpoint of process simplification and energy efficiency.

[0042] - Rate of Urea Addition - There are no particular restrictions on the rate at which the urea solution or solid urea is added. For example, a predetermined amount of urea solution or solid urea may be added all at once, in installments, or sequentially.

[0043] -Timing of Urea Addition- There are no particular restrictions on the timing of urea addition. For example, it may be added during the deammonia reaction at 140-190°C, or during the high molecular weight conversion reaction at 200-280°C. However, from the viewpoint of more reliable suppression of excessive growth, it is preferable to add it during the high molecular weight conversion reaction at 200-280°C.

[0044] [Polyurea Composition] The polyurea composition of this embodiment is (1) a polyurea composition comprising the polyurea of ​​this embodiment and a nickel element, wherein the content of the nickel element in the polyurea composition is 0.05 to 100 ppm by mass (hereinafter sometimes referred to as "polyurea composition (1)"), or (2) a polyurea composition comprising the polyurea of ​​this embodiment and a sodium element, wherein the content of the sodium element in the polyurea composition is 30 to 3,000 ppm by mass (hereinafter sometimes referred to as "polyurea composition (2)"). In other words, the polyurea composition of this embodiment is not particularly limited as long as it contains at least polyurea and at least one of a predetermined amount of nickel and a predetermined amount of sodium, and may contain other components as needed. Polyurea composition (1) may contain 30 to 3,000 ppm by mass of sodium, or less than 30 ppm by mass of sodium, or more than 3,000 ppm by mass of sodium, and polyurea composition (2) may contain 0.05 to 100 ppm by mass of nickel, or less than 0.05 ppm by mass of nickel and more than 100 ppm by mass of nickel. These may be used individually or in combination of two or more. Furthermore, the polyurea contained in polyurea compositions (1) and (2) may be used individually or in combination of two or more.

[0045] The nickel content in polyurea composition (1) is not particularly limited as long as it is between 0.05 and 100 ppm by mass, but is preferably between 0.05 ppm by mass and less than 10 ppm by mass, and more preferably between 0.05 and 1 ppm by mass. If it is above the lower limit of the above range, the thermal stability of the polyurea composition tends to be high, and if it is below the upper limit of the above range, the polyurea composition becomes less likely to be colored. The preferred nickel content in polyurea composition (1) described above can also be applied to polyurea composition (2). The nickel content in polyurea composition (1) or (2) can be determined by the measurement method described in the examples.

[0046] The sodium content in polyurea composition (2) is not particularly limited as long as it is between 30 and 3,000 ppm by mass, but is preferably 50 to 2,500 ppm by mass or more, more preferably 100 to 2,000 ppm by mass, and particularly preferably 200 to 1,500 ppm by mass. If it is above the lower limit of the above range, the polyurea composition will be less likely to be colored during processing, and if it is below the upper limit of the above range, it will be easier to exhibit high transparency. The preferred sodium content in polyurea composition (2) described above can also be applied to polyurea composition (1). The sodium content in polyurea composition (1) or (2) can be determined by the measurement method described in the examples.

[0047] There are no particular restrictions on the polyurea content, but from the viewpoint of achieving both suppression of discoloration and heat resistance of the polyurea composition, it is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more, of 100% by mass of the polyurea composition (1) or (2).

[0048] <Nickel Element> There are no particular restrictions on the origin of the nickel element contained in polyurea composition (1) or that may be contained in polyurea composition (2). It may be derived from nickel added using reagents such as nickel chloride, nickel nitrate, and nickel sulfate, or from reagents used in the production of polyurea (catalysts, heat stabilizers, antioxidants, etc.), or from equipment used in the production of polyurea (reaction vessels, stirring blades, etc.). These may be added individually or in combination of two or more. Among these, from the viewpoint of productivity, it is preferable that the nickel element is derived from equipment used in the production of polyurea (reaction vessels, stirring blades, etc.). Furthermore, there are no particular restrictions on the timing of the inclusion of the above nickel element. It may be added before the production of polyurea (for example, when the raw materials are charged into the reaction vessel), during the production of polyurea (for example, during the polycondensation reaction), or after the production of polyurea (for example, during the production of the molded article described later). These may be added individually or in combination of two or more. Among these, from the viewpoint of productivity, it is preferable that it be added during the production of polyurea (for example, during the polycondensation reaction).

[0049] There are no particular restrictions on the reaction vessels used in the production of polyurea; examples include stainless steel reaction vessels, nickel-chromium alloy reaction vessels, and ceramic reaction vessels. These may be used individually or in combination of two or more. Among these, ceramic reaction vessels are preferred from the viewpoint of productivity and availability.

[0050] There are no particular restrictions on stainless steel reaction vessels; for example, stainless steel reaction vessels made of SUS304, SUS316, etc. These may be used individually or in combination of two or more types. Among these, SUS316 reaction vessels are preferred from the viewpoint of corrosion resistance. There are no particular restrictions on nickel-chromium alloy reaction vessels; for example, Inconel reaction vessels, Hastelloy reaction vessels, etc. These may be used individually or in combination of two or more types. Among these, Hastelloy reaction vessels are preferred from the viewpoint of availability. There are no particular restrictions on ceramic reaction vessels; for example, reaction vessels with a glass lining on the inner surface of the vessel; glass reaction vessels such as glass flasks; etc. These may be used individually or in combination of two or more types. Among these, glass flasks are preferred from the viewpoint of availability.

[0051] <Sodium Element> There are no particular restrictions on the origin of the sodium element that may be contained in polyurea composition (1) or polyurea composition (2). It may be derived from a reagent added using sodium hypophosphite, sodium nitrite, etc., or from a reagent (catalyst, antioxidant, heat stabilizer, etc.) used in the production of polyurea, or from equipment (reaction vessel, stirring blade, etc.) used in the production of polyurea. These may be added individually or in combination of two or more. Among these, from the viewpoint of productivity, it is preferable that the sodium element is derived from equipment (reaction vessel, stirring blade, etc.) used in the production of polyurea. Furthermore, there are no particular restrictions on the timing of the inclusion of the sodium element. It may be added before the production of polyurea (for example, when the raw materials are charged into the reaction vessel), during the production of polyurea (for example, during the polycondensation reaction), or after the production of polyurea (for example, during the production of the molded article described later). These may be added individually or in combination of two or more. Among these, from the viewpoint of productivity, it is preferable that the sodium element is added during the production of polyurea (for example, during the polycondensation reaction). Furthermore, the same type of reaction vessel used in the production of polyurea can be adapted from the equipment described above.

[0052] <Other Components> Polyurea compositions (1) and (2) may further contain other components as needed. There are no particular limitations on the other components as long as they do not impair the effects of the present invention, and examples include auxiliary raw materials for polycondensation reactions (additives added to the polycondensation reaction) such as antioxidants, antistatic agents, flame retardants, flame retardant aids, and heat stabilizers; and additives added during molding of the polyurea composition such as ultraviolet absorbers (UVA), light stabilizers (HALS), glass fibers, carbon fibers, antioxidants, antistatic agents, flame retardants, flame retardant aids, heat stabilizers, mold release agents, dyes and pigments, light diffusers, organic dyes, matting agents, impact resistance modifiers, phosphors, and plasticizers. These may be used individually or in combination of two or more.

[0053] Antioxidants are effective in preventing oxidative degradation of resins in the presence of oxygen. There are no particular restrictions on the antioxidants used, and examples include hindered phenol antioxidants; hindered amine antioxidants; phosphorus-based antioxidants such as sodium hypophosphite; thio-based antioxidants, etc.

[0054] Flame retardants have the effect of suppressing the continuation of the combustion cycle of polymeric organic materials. There are no particular restrictions on the flame retardants, and examples include brominated polymers, antimony oxide, metal hydroxides, and phosphinates.

[0055] A heat stabilizer can prevent thermal degradation of a resin by capturing polymer radicals that are generated when the resin is exposed to high heat in a substantially oxygen-free state. There are no particular limitations on the heat stabilizer, and examples include 2-t-butyl-6-(3'-t-butyl-5'-methyl-hydroxybenzyl)-4-methylphenyl acrylate and 2,4-di-t-amyl-6-(3',5'-di-t-amyl-2'-hydroxy-α-methylbenzyl)phenyl acrylate.

[0056] Ultraviolet absorbers (UVA) are compounds that have the ability to absorb ultraviolet light and are said to primarily function in converting light energy into thermal energy. There are no particular restrictions on ultraviolet absorbers (UVA), and examples include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalate anilides, malonic acid esters, and formamidines.

[0057] A mold release agent is a compound that facilitates the release of a molded product from a mold. There are no particular limitations on the mold release agent, and examples include higher alcohols such as cetyl alcohol and stearyl alcohol; glycerol higher fatty acid esters such as monoglyceride stearate and diglyceride stearate; and so on.

[0058] There are no particular restrictions on the content of other components, but they are preferably 20% by mass or less, more preferably 10% by mass or less, and most preferably 5% by mass or less, in 100% by mass of the polyurea composition (1) or (2).

[0059] [Molded Article] The molded article of this embodiment contains the polyurea of ​​this embodiment. By having such a configuration, a molded article with high mechanical properties and resistance to discoloration can be obtained. That is, the molded article of this embodiment is not particularly limited as long as it contains at least the polyurea of ​​this embodiment, and at least one of the polyurea compositions (1) and (2) of this embodiment may be used instead of the polyurea of ​​this embodiment. The polyurea of ​​this embodiment can be processed into a molded article of any shape by known molding methods such as injection molding, extrusion molding, T-die molding, inflation molding, and hot pressing.

[0060] There are no particular restrictions on the polyurea content in the molded article, but it is preferably 80% by mass or more, more preferably 90% by mass or more, and most preferably 95% by mass or more, and may be 100% by mass, based on 100% by mass of the molded article.

[0061] There are no particular limitations on the applications of the molded articles, and examples include various films such as decorative films and display device films; various sheets; various tubes such as fuel tubes and ultrapure water tubes; various hoses; electrical and electronic components such as printed circuit boards; industrial parts; automotive parts; household goods; medical parts; fibers; hollow molded parts; foamed molded products; and other molded products of any shape. Among these, films and sheets are preferred from the viewpoint of fully utilizing the effects of the present invention.

[0062] When the molded body is a film, there are no particular restrictions on the thickness of the film, but it is preferably 10 to 400 μm, more preferably 20 to 300 μm, and most preferably 40 to 100 μm. When the molded body is a sheet, there are no particular restrictions on the thickness of the sheet, but it is preferably more than 400 μm and 10,000 μm or less, more preferably 500 to 5,000 μm, and most preferably 600 to 2,000 μm. If the thickness is above the lower limit of the above range, it becomes easier to maintain sufficient strength for handling, and if it is below the upper limit of the above range, the molded body becomes easier to handle.

[0063] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples.

[0064] [Polyurea] Polyureas 1 to 11 were prepared using the raw material monomers shown below, as described in Examples 1 to 7 and Comparative Examples 1 to 4. It should be noted that the above polyureas 1 to 11 can also be considered polyurea compositions because they coexist with at least one of a predetermined amount of sodium element derived from the reagent and a predetermined amount of nickel element derived from the equipment (glass flask, reaction vessel).

[0065] <Raw Material Monomers> Urea: Manufactured by Tokyo Chemical Industry Co., Ltd. NMDA: 1,9-nonanediamine MODA: 2-methyl-1,8-octanediamine C6DA: 1,6-hexanediamine, manufactured by Tokyo Chemical Industry Co., Ltd. C8DA: 1,8-octanediamine, manufactured by Tokyo Chemical Industry Co., Ltd. C10DA: 1,10-decanediamine, manufactured by Tokyo Chemical Industry Co., Ltd. MXD: metaxylylenediamine, manufactured by Tokyo Chemical Industry Co., Ltd.

[0066] <Production of Polyurea> (Example 1) In a glass flask equipped with apparatus for distilling off the generated liquid and gas, urea, NMDA, MODA, and sodium hypophosphite (manufactured by Tokyo Chemical Industry Co., Ltd.) were charged in a molar ratio of urea / NMDA / MODA / sodium hypophosphite = 39.4 / 43.5 / 7.7 / 0.1. The mixture was heated from 25°C to 130°C at a flow rate of 50 mL / min under nitrogen for 1 hour, then heated further to 160°C and heated for another hour. After further heating to 230°C, urea in a molar ratio of 9.3 was added and heated for 6 hours to obtain colorless and transparent polyurea 1.

[0067] (Examples 2-5) Polyureas 2-5 were obtained in the same manner as in Example 1, except that the raw materials and their molar ratios shown in Table 1 were used instead of those in Example 1.

[0068] (Example 6) Polyurea 6 was obtained in the same manner as in Example 1, except that the raw materials and their molar ratios shown in Table 1 were used instead of those in Example 1, and that nickel(II) chloride was added in a molar ratio of 0.0008 after urea was added and heated for 6 hours.

[0069] (Example 7) The raw materials and their molar ratios shown in Table 1 were charged into a pressure vessel made of SUS316. After replacing the air in the reaction vessel with nitrogen, the internal pressure of the reaction vessel 1 was maintained at 0.3 MPaG, and the internal temperature was raised from 25°C to 130°C and heated for 1 hour. The temperature was further raised to 160°C and heated for 1 hour. After further raising the temperature to 230°C, urea (solid) in the molar ratio shown in Table 1 was added all at once and heated for 6 hours to obtain colorless and transparent polyurea 7. (Comparative Examples 1-4) Polyureas 8-11 were obtained in the same manner as in Example 1, except that the raw materials and their molar ratios shown in Table 1 were used instead of those in Example 1.

[0070] [Measurement of Polyurea Properties] The following measurements and evaluations were performed on the manufactured polyureas 1 to 11. The measurement and evaluation results are shown in Table 1.

[0071] <Number-average molecular weight Mn and weight-average molecular weight Mw> The number-average molecular weight Mn and weight-average molecular weight Mw of each manufactured polyurea are the number-average molecular weight Mn and weight-average molecular weight Mw converted to polymethyl methacrylate (manufactured by Resonaq Corporation) measured using gel permeation chromatography (GPC) under the following measurement conditions, with each manufactured polyurea as the sample. <Measurement conditions> Measurement device: HLC-8420 GPC Column: 1 x "TSKgel Guard Column SUPER H-H" manufactured by Tosoh Corporation, 2 x "TSKgel SUPER HM-H" manufactured by Tosoh Corporation, 1 x "TSKgel SUPER H-RC" manufactured by Tosoh Corporation Solvent: 12 mM sodium trifluoroacetate-containing hexafluoroisopropanol Flow rate: 0.4 mL / min Measurement temperature: 40°C

[0072] <Amine Value> The amine value of each polyurea prepared was determined as follows: 0.2 g of each polyurea prepared was dissolved in 30 mL of phenol, and 3 mL of methanol was mixed to prepare the sample solution. Titration was performed using thymol blue as an indicator and a 0.01 or 0.1 N aqueous HCl solution. The endpoint was the point at which the solution turned pale pink, and the amine value (terminal amino group content) was calculated using the following formula (2) ([NH ２The amine value (μmol / g) was measured. Formula (2): Amine value [μmol / g] = Titration volume [mL] × Normality [mol / L] ÷ Mass [g] × 1,000 The reagents used to measure the amine value were as follows: Phenol: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Primary methanol: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade Thymol blue: Manufactured by Kanto Chemical Co., Ltd. HCl aqueous solution: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., for volumetric analysis

[0073] <Nickel and Sodium Content> The nickel content in each polyurea produced was determined as follows: 0.1 g of each polyurea produced was mixed with 20 g of nitric acid, and microwave decomposition was performed using ETHOS UP (Milestone General Co., Ltd.). ICP-OES analysis was performed on the microwave-decomposed samples using Thermo Scientific iCAP 7000 Series ICP-OES (Milestone General Co., Ltd.). A calibration curve for the analyte was created using Metal Mixed Standard Solution VII. The reagents used to measure the nickel content are as follows: Nitric acid: For precision analysis, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Metal Mixed Standard Solution VII: For water quality testing, manufactured by Kanto Chemical Co., Ltd.

[0074] <Average number of carbon atoms in the main chain of aliphatic diamine units in polyurea> The average number of carbon atoms in the main chain of aliphatic diamine units in polyurea is calculated by the weighted average of the molar ratio of each component in the aliphatic diamine and the number of carbon atoms in each main chain. For example, in Example 1, it is calculated as 9 × 43.5 / 51.2 + 8 × 7.7 / 51.2 = 8.8.

[0075] <Melting Point (°C)> The melting point (°C) of each manufactured polyurea was measured using a differential scanning calorimeter (DSC25, manufactured by T.A. Instruments, Inc.) according to the method described in JIS K7121:2012. Specifically, under a flow of 50 mL / min of nitrogen, the temperature was raised from 25°C to 240°C at a heating rate of 10°C / min, held at 240°C for 5 minutes, then cooled to 25°C at a heating rate of 10°C / min, held at 25°C for 5 minutes, and then raised to 240°C at a heating rate of 10°C / min. The temperature of the highest endothermic peak was taken as the melting point (°C). However, if a clear endothermic peak was not observed using the above method, specifically in Example 2 and Comparative Example 3, the temperature of the highest endothermic peak was taken as the melting point (°C) when the temperature was raised from 25°C to 240°C at a heating rate of 10°C / min under a flow of 50 mL / min of nitrogen.

[0076] <Ratio (ηEa / ηEb)> The ratio (ηEa / ηEb) of each manufactured polyurea was determined using a rotary rheometer (TA Instruments, "ARES") as follows. Each manufactured polyurea was sandwiched between the parallel discs (25 mm in diameter) of the rotary rheometer, heated to the melting point + 20°C, and measured at a strain of 7% and a frequency of 0.1 to 100 Hz. At that time, the value of the complex viscosity η* at a shear rate of 0.1 (1 / s) was defined as the shear viscosity ηEa (Pa·s), and the value of the complex viscosity η* at a shear rate of 10 (1 / s) was defined as the shear viscosity ηEb (Pa·s). From the obtained shear viscosity ηEa (Pa·s) and shear viscosity ηEb (Pa·s), the ratio (ηEa / ηEb) was calculated.

[0077] <Proportion of High Molecular Weight Components> The proportion of high molecular weight components in each manufactured polyurea was determined as follows. From the data obtained when measuring the number-average molecular weight of each manufactured polyurea, a differential molecular weight distribution curve (vertical axis: value obtained by differentiating the concentration fraction with respect to the logarithm of molecular weight, horizontal axis: logarithm of molecular weight) was created as shown in Figure 1. In the created differential molecular weight distribution curve, when the intensity at the peak top molecular weight M(t) is set to 1, the molecular weight on the high molecular weight side at the point where the intensity becomes 1 / 2 is Mh(t). １／２ ) was set. Then, Mh(t) was applied to the area of ​​the entire region of the differential molecular weight distribution curve (the sum of the parts

[10] and

[11] in Figure 1). １／２The percentage of the area of ​​the high molecular weight region (the part labeled

[10] in Figure 1) was calculated, and this percentage was defined as the percentage of high molecular weight components.

[0078] <Colorability (Yellowness (YI))> The colorability of each manufactured polyurea was evaluated using the yellowness (YI). The yellowness (YI) was determined as follows: Each manufactured polyurea was subjected to a single-acting compression molding machine (Imoto Seisakusho Co., Ltd., "IMC-183B"), with a rotary oil pump to reduce the pressure to -0.1 MPaG, preheated to melting point + 20°C for 5 minutes, and then pressed with 50 kN for 30 seconds. After that, it was cooled at 30 kgf / cm using a cooling press equipped with water jet cooling. ２ A pressed film with a thickness of 250 μm was prepared by pressing for 5 minutes. A 30 x 30 mm square piece was cut from the obtained film, and the yellowness (YI) of the test piece was measured using a spectroscopic haze meter SH7000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with the method compliant with JIS K7373:2006. The yellowness (YI) was evaluated according to the following evaluation criteria: [Evaluation Criteria] A: Less than 1.5 B: 1.5 or more and less than 2.5 C: 2.5 or more If the evaluation is A, it can be said that polyurea is particularly difficult to color. Also, even if the evaluation is B, it can be said that polyurea is sufficiently difficult to color. On the other hand, if the evaluation is C, it cannot be said that polyurea is difficult to color.

[0079] <Mechanical Properties (Tensile Strain)> The mechanical properties of each manufactured polyurea were evaluated using tensile strain. Tensile strain was determined as follows: Each manufactured polyurea was mixed using a small kneader (XPLORE INSTRUMENTS, "MC15-HT") at a stirring speed of 50 rpm, a kneading temperature of melting point + 30°C, and a mold temperature of melting point - 60°C to produce small test specimens of type 1BA. These were then crystallized in a 110°C constant temperature bath for 6 hours to obtain dumbbell test specimens. The obtained dumbbell test specimens were measured for elongation at break at 23°C using a Shimadzu Corporation "Autograph AG2000B". Specifically, the chuck distance was 50 mm and the test speed was 5 mm / min. The mechanical properties were evaluated according to the following evaluation criteria. [Evaluation Criteria] A: 20% or more B: 10% or more but less than 20% C: Less than 10% If the evaluation is A, the mechanical properties of polyurea can be said to be particularly high. Even if the evaluation is B, the mechanical properties of polyurea can be said to be sufficiently high. On the other hand, if the evaluation is C, the mechanical properties of polyurea cannot be said to be high.

[0080]

[0081] As can be seen from the results shown in Table 1, the polyureas 1 to 7 of the present invention (polyureas having a number-average molecular weight of 6,000 to 50,000 and a ratio (ηEa / ηEb) of 1.1 to 10) were found to have higher mechanical properties and be less prone to discoloration compared to the polyureas 8 to 11 that are not part of the present invention (polyureas that do not satisfy at least one of the following conditions: a number-average molecular weight of 6,000 to 50,000 and a ratio (ηEa / ηEb) of 1.1 to 10).

[0082] According to the present invention, it is possible to provide a polyurea having high mechanical properties and being difficult to color, as well as a polyurea composition containing the polyurea and a molded article. The polyurea composition of the present invention can be used, for example, in various substrates for electronic components, housings for electronic components, casings for electronic components, coverlays, wire coatings, laminate films, tubes for home appliances, fuel piping, industrial hydraulic belts, airless tires, inner liners for tires, sealing members, diaphragms, wire cables, bearing retainers, hair dryers, bobbin cases, mixing faucets, medical catheters, electronic paper, foldable device films, foldable sheets, wearable devices, films, sheets, etc.

[0083] 1 Differential molecular weight distribution curve 10 Mh(t １／２ ) High molecular weight region of 11 Mh(t １／２ Low molecular weight region (less than )

Claims

1. A polyurea having a number-average molecular weight Mn of 6,000 to 50,000, and a ratio (ηEa / ηEb) of the shear viscosity ηEa (Pa·s) at a shear rate of 0.1 (1 / s) measured at the melting point + 20°C to the shear viscosity ηEb (Pa·s) at a shear rate of 10 (1 / s) measured at the melting point + 20°C to 1.1 to 10.

0.

2. In the differential molecular weight distribution curve of the number-average molecular weight of the polyurea, when the intensity at the peak-top molecular weight M(t) is set to 1, the molecular weight on the high molecular weight side at the point where the intensity becomes 1 / 2 is Mh(t). １／２ In this case, the Mh(t) is the area of ​​the entire region of the differential molecular weight distribution curve. １／２ The polyurea according to claim 1, wherein the area ratio of the high molecular weight region is 5 to 20%.

3. The polyurea according to claim 1, wherein the molecular weight distribution Mw / Mn is 1.0 to 3.

0.

4. The polyurea according to claim 1, wherein the carbonyl group in the urea bond is derived from a urea-based compound.

5. The polyurea according to claim 1, wherein the polyurea contains aliphatic diamine units, and the average number of carbon atoms in the main chain of the aliphatic diamine units is 8.5 or more.

6. The polyurea according to claim 1, wherein the number average molecular weight and amine value satisfy the following formula (1): Formula (1): 2.0 ≤ (number average molecular weight × amine value [μmol / g]) / 10 ６ ≤4.0 7. The polyurea according to claim 1, wherein the melting point is 120 to 280°C.

8. A polyurea composition comprising the polyurea described in any one of claims 1 to 7 and a nickel element, wherein the content of the nickel element in the polyurea composition is 0.05 to 100 ppm by mass.

9. A polyurea composition comprising the polyurea described in any one of claims 1 to 7 and an element of sodium, wherein the content of the element of sodium in the polyurea composition is 30 to 3,000 ppm by mass.

10. A molded article comprising the polyurea described in any one of claims 1 to 7.

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