Thermoplastic polyurea and molded article

Abstract

A thermoplastic polyurea having an aliphatic diamine unit (A) having a linear aliphatic hydrocarbon group and an aliphatic diamine unit (B) having a methyl-branched aliphatic hydrocarbon group with 7 to 12 carbon atoms in the main chain.

Description

Technical Field

[0001] The present invention relates to thermoplastic polyurea and a molded article.

Background Art

[0002] Polyurea is excellent in heat resistance, mechanical strength, and chemical resistance, and is used in injection molded products, fibers, coating agents, etc. Conventional polyurea has been produced by polymerization of urea and formaldehyde or polymerization of diisocyanate and diamine. However, polyurea obtained by the conventional method is a polymer that is difficult to melt-mold even if it is thermosetting or thermoplastic. Therefore, development of thermoplastic polyurea that is easily melt-molded has been demanded.

[0003] In order to solve the above problems, polymerization using urea and diamine has been proposed so far. For example, as the diamine component, two or more linear alkylene diamines having different carbon numbers (see, for example, Patent Document 1), a primary diamine having at least one alkyl group having more than 3 carbon atoms at any carbon of a linear saturated hydrocarbon group having a specific carbon number (see, for example, Patent Document 2), a mixed system of a primary diamine having at least one alkyl group having more than 10 carbon atoms at any carbon of a linear saturated aliphatic hydrocarbon group having a specific carbon number and a linear alkylene diamine having a specific carbon number (see, for example, Patent Document 3) are disclosed. By the techniques described in Patent Documents 1 to 3, polyurea having excellent various physical and chemical properties such as good mechanical properties, moldability, and dyeability has been developed.

[0004] However, thermoplastic polyurea having excellent chemical resistance and capable of suppressing coloring during melt molding has not been obtained.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

[0006] An object of the present invention is to provide a thermoplastic polyurea having excellent chemical resistance and capable of suppressing coloring during melt molding, and a molded article containing the thermoplastic polyurea. [Means for Solving the Problems]

[0007] As a result of intensive studies, the present inventors have found that a thermoplastic polyurea having excellent chemical resistance and capable of suppressing coloring during melt molding can be obtained by having an aliphatic diamine unit (A) having a linear aliphatic hydrocarbon group and an aliphatic diamine unit (B) having a methyl-branched aliphatic hydrocarbon group with 7 to 12 carbon atoms in the main chain, and thus completed the present invention.

[0008] That is, the present invention is as follows in [1] to [7] below. [1] A thermoplastic polyurea having an aliphatic diamine unit (A) having a linear aliphatic hydrocarbon group and an aliphatic diamine unit (B) having a methyl-branched aliphatic hydrocarbon group with 7 to 12 carbon atoms in the main chain. [2] The thermoplastic polyurea according to [1] above, wherein the molar ratio (A / B) of the aliphatic diamine unit (A) to the aliphatic diamine unit (B) is 99 / 1 to 30 / 70. [3] The thermoplastic polyurea according to [1] or [2] above, wherein the average number of carbon atoms of the linear aliphatic hydrocarbon group is 7 to 11. [4] The thermoplastic polyurea according to any one of [1] to [3] above, wherein the bonds between the aliphatic diamine unit (A) and the aliphatic diamine unit (B), the bonds between the aliphatic diamine units (A), and the bonds between the aliphatic diamine units (B) are urea bonds. [5] The thermoplastic polyurea according to any one of [1] to [4] above, wherein the carbonyl group in the urea bond of the thermoplastic polyurea is derived from urea. [6] The thermoplastic polyurea according to any one of [1] to [5] above, having a melting point of 220°C or lower. [7] A molded article comprising the thermoplastic polyurea according to any one of [1] to [6] above. [Advantages of the Invention]

[0009] According to the present invention, it is possible to provide a thermoplastic polyurea having excellent chemical resistance and capable of suppressing coloring during melt molding, and a molded article containing the thermoplastic polyurea. [Modes for Carrying Out the Invention]

[0010] Hereinafter, an example of an embodiment of the present invention will be described. However, the embodiments shown below are examples for embodying the technical idea of the present invention, and the present invention is not limited to the following description. In this specification, although preferred forms of the embodiments are shown, a combination of two or more of the individual preferred forms is also a preferred form. For matters indicated by numerical ranges, when there are several numerical ranges, preferred forms can be obtained by selectively combining the lower limit values and the upper limit values thereof. In this specification, when a numerical range of "XX to YY" is described, it means "XX or more and YY or less". In this specification, "polymer" means thermoplastic polyurea, "structural unit" means "unit constituting the polymer", and "aliphatic diamine unit" means "structural unit derived from aliphatic diamine". In this specification, "easy melt molding" means that the number average molecular weight (Mn) and the weight average molecular weight (Mw) are not too high, and the melt viscosity is not too high, so that melt molding is easy.

[0011] [Thermoplastic Polyurea] The thermoplastic polyurea of the present invention has an aliphatic diamine unit (A) having a linear aliphatic hydrocarbon group (hereinafter sometimes referred to as "aliphatic diamine unit (A)") and an aliphatic diamine unit (B) having a methyl-branched aliphatic hydrocarbon group with 7 to 12 carbon atoms in the main chain (hereinafter sometimes referred to as "aliphatic diamine unit (B)"), and may further have other structural units as necessary.

[0012] In the thermoplastic polyurea of the present invention, it is preferable that the bond between the aliphatic diamine unit (A) and the aliphatic diamine unit (B), the bond between the aliphatic diamine units (A), and the bond between the aliphatic diamine units (B) are all urea bonds (-NH-C(=O)-NH-). The thermoplastic polyurea may contain other bonds other than the urea bond as long as the effects of the present invention are not impaired.

[0013] The carbonyl group (-C(=O)-) in the urea bond (-NH-C(=O)-NH-) of the thermoplastic polyurea of the present invention is not particularly limited and may be derived from urea, isocyanate, carbon dioxide, carbonate, or phosgene. However, from the viewpoints of productivity, raw material toxicity, and availability, it is preferably derived from urea. Here, being derived from urea is not limited to being derived from urea, but also includes being derived from urea derivatives such as methylene diurea and ethylene diurea.

[0014] The thermoplastic polyurea of the present invention can be obtained, for example, by heating and reacting an aliphatic diamine having an aliphatic hydrocarbon group and urea or the like in a substantially equimolar ratio, preferably in an inert gas atmosphere, with or without dissolving in a solvent such as water, phenol, or metacresol, and then, if a solvent is present, distilling it off while completing the polycondensation reaction. Note that the aliphatic diamine does not include urea (H2N-C(=O)-NH2).

[0015] In 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 increased. The generation of ammonia becomes active again at about 140 to 190 °C. Control the temperature at this time, distill off the solvent if it exists, and increase the temperature again. After the deammoniation reaction by heating is completed, if the heating reaction is continued at a temperature of about 200 to 280 °C under reduced pressure, the polycondensation reaction proceeds smoothly and a linear copolymer is obtained.

[0016] Also, as auxiliary raw materials for the polycondensation reaction, a terminal blocking agent, an additive, etc. may be added. Examples of the terminal blocking agent include monoamines such as hexylamine, octylamine, cyclohexylamine, and aniline; monocarboxylic acids such as acetic acid, lauric acid, and benzoic acid. These may be used alone or in combination of two or more. As the addition amount of the terminal blocking agent, 5 mol% or less is preferable with respect to the aliphatic diamine compound. Examples of the additive include an antioxidant, an antistatic agent, a flame retardant, a flame retardant aid, a heat stabilizer, etc. These may be used alone or in combination of two or more.

[0017] Regarding the melting point of the thermoplastic polyurea of the present invention, from the viewpoint of reducing coloring during melt molding, it is preferably 220 °C or lower, more preferably 215 °C or lower, particularly preferably 210 °C or lower. On the other hand, from the viewpoint of heat resistance, it is preferably 150 °C or higher, more preferably 160 °C or higher, particularly preferably 170 °C or higher. Regarding the melting point of the thermoplastic polyurea of the present invention, it is preferably 150 to 220 °C, more preferably 160 to 215 °C, particularly preferably 170 to 210 °C or lower. The melting point of the thermoplastic polyurea of the present invention can be measured by the method used in the examples described later.

[0018] Regarding the sequence order of the aliphatic diamine unit (A), the aliphatic diamine unit (B), and any other structural unit in the thermoplastic polyurea of the present invention, there is no particular limitation, and it may be any of random, block, alternating, etc.

[0019] As for the total of the aliphatic diamine unit (A) and the aliphatic diamine unit (B) with respect to 100 mol% of all the structural units (excluding the bonding parts between the structural units) in the thermoplastic polyurea, it is preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more, and most preferably 100 mol%. That is, it is preferable that there are no other structural units other than the aliphatic diamine unit (A) and the aliphatic diamine unit (B). The total of the aliphatic diamine unit (A) and the aliphatic diamine unit (B) with respect to 100 mol% of all the structural units (excluding the bonding parts between the structural units) in the thermoplastic polyurea can be measured, for example, by NMR. The ratio of the diamine units constituting the aliphatic diamine unit (A), the aliphatic diamine unit (B), etc. 1 In the 1H-NMR measurement, it is calculated by the integral values of the peak at 0.6 to 1.2 ppm attributed to the proton bonded to the methyl branch of the aliphatic diamine unit (B), the peak at 1.2 to 2.0 ppm attributed to the proton bonded to the methylene chain of the aliphatic diamine unit (A) or the aliphatic diamine unit (B), and the peak at 2.0 to 3.0 ppm attributed to the proton bonded to the methylene chain adjacent to the amino group of the aliphatic diamine unit (A) or the aliphatic diamine unit (B). Incidentally, the "bonding parts between the structural units" means, for example, (1) when the structural units are two types of the aliphatic diamine unit (A) and the aliphatic diamine unit (B), the bond between the aliphatic diamine unit (A) and the aliphatic diamine unit (B), the bond between the aliphatic diamine units (A), and the bond between the aliphatic diamine units (B), which are three types of bonding parts, and (2) when the structural units are three types of the aliphatic diamine unit (A), the aliphatic diamine unit (B), and other structural units, the bond between the aliphatic diamine unit (A) and the aliphatic diamine unit (B), the bond between the aliphatic diamine unit (A) and other structural units, the bond between the aliphatic diamine unit (B) and other structural units, the bond between the aliphatic diamine units (A), the bond between the aliphatic diamine units (B), and the bond between other structural units, which are six types of bonding parts.

[0020] The weight average molecular weight (Mw) of the thermoplastic polyurea is preferably 10,000 or more from the viewpoints of chemical resistance and mechanical strength, while it is preferably 100,000 or less from the viewpoint of melt moldability. The weight average molecular weight (Mw) of the thermoplastic polyurea is preferably from 10,000 to 100,000. The weight average molecular weight (Mw) of the thermoplastic polyurea is the weight average molecular weight (Mw) in terms of polymethyl methacrylate (manufactured by JSR Corporation) measured using gel permeation chromatography (GPC) under the following measurement conditions. <Measurement Conditions> Measuring apparatus: HLC-8320GPC Column: One TSKgel SUPER AW-H Guard Column manufactured by Tosoh Corporation Two TSKgel SUPER AWM-H manufactured by Tosoh Corporation One TSKgel SUPER H-RC manufactured by Tosoh Corporation Solvent: Hexafluoroisopropanol containing 12 mM sodium trifluoroacetate Flow rate: 0.5 mL / min Measurement temperature: 40°C

[0021] The number average molecular weight (Mn) of the thermoplastic polyurea is preferably 2,000 or more from the viewpoints of chemical resistance and mechanical strength, while it is preferably 50,000 or less from the viewpoint of melt moldability. The number average molecular weight (Mn) of the thermoplastic polyurea is preferably from 2,000 to 50,000. The number average molecular weight (Mn) of the thermoplastic polyurea is the number average molecular weight (Mn) in terms of polymethyl methacrylate (manufactured by JSR Corporation) measured using gel permeation chromatography (GPC) under the following measurement conditions. <Measurement Conditions> Measuring apparatus: HLC-8320GPC Column: One TSKgel SUPER AW-H Guard Column manufactured by Tosoh Corporation Two TSKgel SUPER AWM-H manufactured by Tosoh Corporation One TSKgel SUPER H-RC manufactured by Tosoh Corporation Solvent: Hexafluoroisopropanol containing 12 mM sodium trifluoroacetate Flow rate: 0.5 mL / min Measurement temperature: 40 °C

[0022] From the viewpoint of manufacturing difficulty, the molecular weight distribution (Mw / Mn) of the thermoplastic polyurea is preferably 1.1 or more, while from the viewpoint of melt moldability, it is preferably 10 or less. The molecular weight distribution (Mw / Mn) of the thermoplastic polyurea is preferably 1.1 to 10.

[0023] <Aliphatic diamine unit (A)> The aliphatic diamine unit (A) is a structural unit derived from an aliphatic diamine having a linear aliphatic hydrocarbon group, and may further have other groups other than the hydrocarbon group, or may not have them, as necessary. Here, the aliphatic diamine having a linear aliphatic hydrocarbon group means an aliphatic diamine in which amino groups are bonded to both ends of the linear aliphatic hydrocarbon group. The linear aliphatic hydrocarbon group means a linear divalent aliphatic hydrocarbon group having no branched chain. The linear aliphatic hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group, but is preferably a saturated hydrocarbon group. The linear aliphatic hydrocarbon group preferably has an unsubstituted hydrocarbon group containing only carbon and hydrogen.

[0024] Examples of the aliphatic diamine having a linear aliphatic hydrocarbon group that constitutes the aliphatic diamine unit (A) include 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine (1,5-pentamethylenediamine), 1,6-hexanediamine (1,6-hexamethylenediamine), 1,7-heptanediamine (1,7-heptamethylenediamine), 1,8-octanediamine (1,8-octamethylenediamine), 1,9-nonanediamine (1,9-nonamethylenediamine), 1,10-decanediamine (1,10-decamethylenediamine), 1,11-undecanediamine (1,11-undecamethylenediamine), 1,12-dodecanediamine (1,12-dodecamethylenediamine), and the like. These may be used alone or in combination of two or more. Among these, from the viewpoint of achieving both reduction of coloring during melt molding and chemical resistance, 1,7-heptanediamine (1,7-heptamethylenediamine), 1,8-octanediamine (1,8-octamethylenediamine), 1,9-nonanediamine (1,9-nonamethylenediamine), 1,10-decanediamine (1,1,0-decamethylenediamine), 1,11-undecanediamine (1,11-undecamethylenediamine), and 1,12-dodecanediamine (1,12-dodecamethylenediamine) are preferable, and particularly 1,9-nonanediamine (1,9-nonamethylenediamine) is preferable.

[0025] The aliphatic diamine unit (A) may be used alone or in combination of two or more. When there are two or more aliphatic diamine units (A), the molar amount of the aliphatic diamine unit (A) means the total of the molar amounts of the respective aliphatic diamine units (A).

[0026] The average number of carbon atoms of the linear aliphatic hydrocarbon group in the aliphatic diamine unit (A) is not particularly limited, but from the viewpoint of achieving both improvement of the chemical resistance of the thermoplastic polyurea and suppression of coloring during melting, it is preferably 7 or more and 11 or less, more preferably 8 or more and 10 or less, and particularly preferably 9. The "average number of carbon atoms of the linear aliphatic hydrocarbon group in the aliphatic diamine unit (A)" is calculated based on the molar ratio of each component in the aliphatic diamine (A). For example, in Example 5 described later, it is calculated as 9×1 / (1 + 84) + 12×84 / (1 + 84) = 12. In the calculation of the above average number of carbon atoms, the digits after the decimal point are rounded off.

[0027] <Aliphatic diamine unit (B)> The aliphatic diamine unit (B) is a structural unit derived from an aliphatic diamine having a methyl-branched aliphatic hydrocarbon group with 7 to 12 main chain carbon atoms, and may further have other groups if necessary, or may not have other groups.

[0028] The methyl-branched aliphatic hydrocarbon group means a divalent aliphatic hydrocarbon group having a methyl group as a branched chain, and does not include a branched aliphatic hydrocarbon group having a methyl group and other branched chains (for example, an ethyl group, a propyl group) as branched chains. By setting the branched group in the aliphatic hydrocarbon group in the aliphatic diamine unit (B) to a methyl group instead of an ethyl group or a propyl group, the thermoplastic polyurethane can be more easily aggregated and the crystallinity can be improved compared with the case where the branched group is an ethyl group or a propyl group, thereby improving the chemical resistance of the thermoplastic polyurethane. By setting the number of main chain carbon atoms of the aliphatic diamine unit (B) to a certain number or more, the aggregation inhibitory effect by the branched group can be reduced, and the chemical resistance can be improved. In addition, due to having a methyl-branched group, the crystallinity is reduced compared with the case where there is no branched group, so that melt molding at a low temperature is possible and the coloring during melt molding is reduced.

[0029] Examples of the aliphatic diamine having a methyl-branched aliphatic hydrocarbon group with 7 to 12 carbon atoms in the main chain, which constitutes the aliphatic diamine unit (B), include, for example, 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, 2,4,4-trimethyl-1,8-octanediamine, and the like. These may be used alone or in combination of two or more. Among these, from the viewpoint of achieving both chemical resistance and reduction of coloring during melt molding, preferably 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, more preferably 2-methyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 2-methyl-! 9-nonanediamine, 2-methyl-1,10-decanediamine, particularly preferably 2-methyl-1,8-octanediamine and 2-methyl-1,9-nonanediamine.

[0030] The aliphatic diamine unit (B) may be used alone or as a mixture of two or more. When there are two or more aliphatic diamine units (B), the molar amount of the aliphatic diamine unit (B) means the total of the molar amounts of each aliphatic diamine unit (B).

[0031] The number of carbon atoms in the main chain of the aliphatic diamine unit (B) is not particularly limited as long as it is 7 to 12, but from the viewpoint of achieving both chemical resistance and reduction of coloring during melt molding, preferably 7 to 11, more preferably 7 to 10, and particularly preferably 8 to 9. When the methyl-branched aliphatic hydrocarbon group in the aliphatic diamine unit (B) has 7 or more carbon atoms in the main chain, it is possible to maintain chemical resistance while suppressing coloring during the melt molding of the thermoplastic polyurea. On the other hand, when the main chain has 12 or fewer carbon atoms, the chemical resistance of the thermoplastic polyurea can be improved. Note that the number of carbon atoms in the main chain of the aliphatic diamine unit (B) is the "number of carbon atoms excluding the carbon atoms of the methyl branch". For example, the number of carbon atoms in the main chain of "2-methyl-1,8-octanediamine" is "8".

[0032] The number of methyl groups as the branched chain may be 1 or a plurality of 2 or more. The methyl-branched aliphatic hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group, but is preferably a saturated hydrocarbon group. The methyl-branched aliphatic hydrocarbon group is preferably an unsubstituted hydrocarbon group having only carbon and hydrogen.

[0033] The molar ratio (A / B) of the aliphatic diamine unit (A) to the aliphatic diamine unit (B) is not particularly limited, but from the viewpoint of achieving both improved chemical resistance and suppression of coloring during melting, it is preferably 99 / 1 to 30 / 70, more preferably 95 / 5 to 45 / 55, still more preferably 90 / 10 to 60 / 40, and particularly preferably 90 / 10 to 80 / 20.

[0034] By being biased towards either the aliphatic diamine unit (A) or the aliphatic diamine unit (B), it strongly has the characteristics of a thermoplastic polyurea composed of only one of the diamines and becomes a characteristic thermoplastic polyurea. That is, within the preferred range of the molar ratio (A / B) of the above-described aliphatic diamine unit (A) to the aliphatic diamine unit (B), the higher the proportion of the aliphatic diamine unit (A), the better the chemical resistance, and the higher the proportion of the aliphatic diamine unit (B), the higher the effect of reducing coloring during melt molding.

[0035] The thermoplastic polyurea of the present invention can be processed into a molded article described below by known molding methods such as injection molding and extrusion molding. Further, it can be processed into various films by known film-forming methods such as the T-die method, inflation method, and hot press method. In addition, the thermoplastic polyurea of the present invention and the thermoplastic polyurea composition containing a viscosity stabilizer may be processed into a molded article by the above molding method.

[0036] The viscosity stabilizer is not particularly limited, and examples thereof include monobasic acids, alkyl monoamides, monoamines, N-acylalkylenediamines, and the like.

[0037] [Molded article] The molded article of the present invention contains the thermoplastic polyurea of the present invention. The molded article of the present invention refers to a composition containing the thermoplastic polyurea of the present invention processed into various molded articles by known molding methods such as injection molding, extrusion molding, T-die method, inflation method, and hot press method. Examples of the uses of the molded article of the present invention include electrical and electronic parts, automotive parts, industrial parts, household goods, medical parts, fibers, films, sheets, tubes, hoses, hollow molded parts, foamed molded products, and molded products of any other shape.

Examples

[0038] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, “%” and “parts” represent “mass %” and “parts by mass”, respectively, unless otherwise specified. In addition, the measurement methods and evaluation methods employed in the following examples and comparative examples are shown below.

[0039] [Melting point (°C)] The melting point of the obtained polymer was measured by a differential scanning calorimeter according to the method described in JIS K7121:2012. Specifically, under a nitrogen flow of 50 mL / min, the temperature was raised from 25 °C to 240 °C at a rate of 10 °C / min, held at 240 °C for 5 minutes, then cooled to 25 °C at a rate of 10 °C / min, and after holding at 25 °C for 5 minutes, when the temperature was raised to 240 °C at a rate of 10 °C / min, the temperature of the endothermic peak on the highest temperature side was taken as the polymer melting point.

[0040] [Chemical resistance] Tests in accordance with JIS K7114:2001 were carried out. Specifically, the prepared dumbbell test pieces were conditioned at 23 °C and 50% RH, and then immersed in 100 mL of solvent at 23 °C for 1 week. After immersion for 1 week, the test pieces were taken out from the solvent, and the tensile physical properties were evaluated by a tensile test. The solvent resistance was judged according to the following criteria using the retention rate calculated from the following formula 1. Methanol (manufactured by FUJIFILM Wako Pure Chemical Corporation) was used as the solvent. Retention rate (%) = (tensile modulus after solvent immersion / tensile modulus before solvent immersion) × 100... (Formula 1) [Judgment criteria] A: Retention rate ≥ 60% B: 60% > Retention rate ≥ 40% C: 40% > Retention rate

[0041] [Coloration suppression] The degree of coloration suppression of the press film was visually judged according to the following criteria. [Judgment criteria] A: Colorless and transparent B: Slightly yellowed C: Clearly yellowed

[0042] 1 [1H - NMR measurement] The mixing ratio of the 2,2,4 - trimethyl - 1,6 - hexanediamine / 2,4,4 - trimethyl - 1,6 - hexanediamine mixture (manufactured by Tokyo Chemical Industry Co., Ltd.) 1 ​It was calculated from 1H-NMR measurement. Specifically, an NMR measuring device JMTC-40 / 54 / JJ / YH (manufactured by JEOL) was used, and 5 mg of the sample was dissolved in 1 mL of chloroform-d1 (manufactured by Sigma Aldrich). The measurement conditions were set to 16 accumulations and a measurement temperature of 22°C. The mixing ratio was determined from the integral values of the peaks at 2.4 to 2.5 ppm attributed to the protons bonded to the 1-position of 2,2,4-trimethyl-1,6-hexanediamine and the protons bonded to the 1-position of 2,4,4-trimethyl-1,6-hexanediamine, the peaks at 2.5 to 2.6 ppm attributed to the protons bonded to the 1-position of 2,4,4-trimethyl-1,6-hexanediamine, and the peaks at 2.6 to 2.8 ppm attributed to the protons bonded to the 6-position of 2,2,4-trimethyl-1,6-hexanediamine and 2,4,4-trimethyl-1,6-hexanediamine, and it was found that 2,2,4-trimethyl-1,6-hexanediamine:2,4,4-trimethyl-1,6-hexanediamine = 35:65 [mol%].

[0043] (Example 1) <Polymer production> Into a flask equipped with a device capable of distilling off the generated liquid and gas, urea (manufactured by Tokyo Chemical Industry Co., Ltd.), 1,9-nonanediamine, and 2-methyl-1,8-octanediamine were charged in a molar ratio of urea / 1,9-nonanediamine / 2-methyl-1,8-octanediamine = 50.0 / 42.5 / 7.5. While flowing nitrogen at 50 mL / min, the temperature was raised from 25°C to 130°C and heated for 1 hour, then further raised to 160°C and heated for 1 hour. After further raising the temperature to 240°C and heating for 3 hours, a colorless transparent polymer was obtained. The number average molecular weight of the obtained polymer was 5200, the weight average molecular weight was 14200, and the molecular weight distribution was 2.7. The melting point of the obtained polymer was measured. The measurement results are shown in Table 1.

[0044] <Press film forming> Using a single-action compression molding machine ("IMC-183B" manufactured by Imoto Seisakusho) for the obtained polymer, and using an oil rotary pump, the pressure was reduced to -0.1 MPaG, preheated at the melting point + 20°C for 5 minutes, and then pressed at 50 kN for 30 seconds. Then, using a cooling press device equipped with water flow cooling, at 70 kgf / cm2 It was pressed for 5 minutes to produce a pressed film with a thickness of 125 μm. The produced pressed film was evaluated for coloring suppression. The evaluation results are shown in Table 1.

[0045] <Production of dumbbell test pieces> Using a small kneader ("MC15-HT" manufactured by XPLORE INSTRUMENTS), the obtained polymer was used to produce small test piece type 1BA at a stirring speed of 50 rpm, a kneading temperature of the melting point + 40°C, and a mold temperature of the melting point - 60°C, and then crystallized in a constant temperature bath at 110°C for 6 hours to obtain dumbbell test pieces. The obtained dumbbell test pieces were evaluated for chemical resistance. The evaluation results are shown in Table 1.

[0046] (Example 2) In the production of the polymer, except that the molar ratio of urea, 1,9-nonanediamine, and 2-methyl-1,8-octanediamine was changed from 50.0 / 42.5 / 7.5 to 50.0 / 32.5 / 17.5, polymer production, press film forming, and dumbbell test piece production were carried out in the same manner as in Example 1. The number average molecular weight of the obtained polymer was 6500, the weight average molecular weight was 14500, and the molecular weight distribution was 2.2. The obtained measurement results and evaluation results are shown in Table 1.

[0047] (Example 3) In the production of the polymer, except that the molar ratio of urea, 1,9-nonanediamine, and 2-methyl-1,8-octanediamine was changed from 50.0 / 42.5 / 7.5 to 50.0 / 25.0 / 25.0, polymer production, press film forming, and dumbbell test piece production were carried out in the same manner as in Example 1. The number average molecular weight of the obtained polymer was 4900, the weight average molecular weight was 15000, and the molecular weight distribution was 3.1. The obtained measurement results and evaluation results are shown in Table 1.

[0048] (Example 4) In the production of the polymer, instead of using urea, 1,9-nonanediamine, and 2-methyl-1,8-octanediamine at a molar ratio of 50.0 / 42.5 / 7.5, the polymer was produced, press film formed, and dumbbell test pieces were prepared in the same manner as in Example 1, except that urea, 1,9-nonanediamine, 1,10-decanediamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 2-methyl-1,8-octanediamine were used at a molar ratio of 50.0 / 0.5 / 42.0 / 7.5. The number average molecular weight of the obtained polymer was 5900, the weight average molecular weight was 13900, and the molecular weight distribution was 2.3. The obtained measurement results and evaluation results are shown in Table 1.

[0049] (Example 5) In the production of the polymer, instead of using urea, 1,9-nonanediamine, and 2-methyl-1,8-octanediamine at a molar ratio of 50.0 / 42.5 / 7.5, the polymer was produced, press film formed, and dumbbell test pieces were prepared in the same manner as in Example 1, except that urea, 1,9-nonanediamine, 1,12-dodecanediamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 2-methyl-1,8-octanediamine were used at a molar ratio of 50.0 / 0.5 / 42.0 / 7.5. The number average molecular weight of the obtained polymer was 4500, the weight average molecular weight was 15700, and the molecular weight distribution was 3.5. The obtained measurement results and evaluation results are shown in Table 1.

[0050] (Comparative Example 1) In the production of the polymer, instead of using urea, 1,9-nonanediamine, and 2-methyl-1,8-octanediamine at a molar ratio of 50.0 / 42.5 / 7.5, the polymer was produced, press film formed, and dumbbell test pieces were prepared in the same manner as in Example 1, except that urea, 1,10-decanediamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 2-methyl-1,5-pentanediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were used at a molar ratio of 50.0 / 42.5 / 7.5. The number average molecular weight of the obtained polymer was 5100, the weight average molecular weight was 12700, and the molecular weight distribution was 2.5. The obtained measurement results and evaluation results are shown in Table 1.

[0051] (Comparative Example 2) In the production of the polymer, instead of using urea, 1,9-nonanediamine, and 2-methyl-1,8-octanediamine in a molar ratio of 50.0 / 42.5 / 7.5, polymer production, press film forming, and dumbbell test piece production were carried out in the same manner as in Example 1, except that urea, 1,10-decanediamine, and 1,3-pentanediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were used in a molar ratio of 50.0 / 42.5 / 7.5. The number average molecular weight of the obtained polymer was 7000, the weight average molecular weight was 13400, and the molecular weight distribution was 1.9. The obtained measurement results and evaluation results are shown in Table 1.

[0052] (Comparative Example 3) In the production of the polymer, instead of using urea, 1,9-nonanediamine, and 2-methyl-1,8-octanediamine in a molar ratio of 50.0 / 42.5 / 7.5, polymer production, press film forming, and dumbbell test piece production were carried out in the same manner as in Example 1, except that urea and 1,10-decanediamine were used in a molar ratio of 50.0 / 50.0. The number average molecular weight of the obtained polymer was 4500, the weight average molecular weight was 14900, and the molecular weight distribution was 3.3. The obtained measurement results and evaluation results are shown in Table 1.

[0053] (Comparative Example 4) In the production of the polymer, instead of using urea, 1,9-nonanediamine, and 2-methyl-1,8-octanediamine in a molar ratio of 50.0 / 42.5 / 7.5, polymer production, press film forming, and dumbbell test piece production were carried out in the same manner as in Example 1, except that urea and a 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine mixture (manufactured by Tokyo Chemical Industry Co., Ltd.) were used in a molar ratio of 50.0 / 50.0. The number average molecular weight of the obtained polymer was 4200, the weight average molecular weight was 17100, and the molecular weight distribution was 4.1. The obtained measurement results and evaluation results are shown in Table 1.

[0054]

Table 1

[0055] From the comparison between Examples 1 to 5 and Comparative Examples 1 to 4, it can be seen that the thermoplastic polyurea having an aliphatic diamine unit (A) with a linear aliphatic hydrocarbon group and an aliphatic diamine unit (B) with a methyl-branched aliphatic hydrocarbon group having 7 to 12 carbon atoms in the main chain is excellent in chemical resistance and the occurrence of coloring is suppressed. From the comparison between Example 5 and Example 1, it can be seen that as the average number of carbon atoms of the linear aliphatic hydrocarbon group in the aliphatic diamine unit (A) decreases from 12 (Example 5) to 9 (Example 1), the melting point increases (196 °C → 208 °C) and the chemical resistance improves (B → A).

[0056] From the comparison between Example 3 and Example 1, it can be seen that as the molar ratio (linear aliphatic diamine / branched aliphatic diamine) is changed from 50 / 50 (Example 3) to 85 / 15 (Example 1), the melting point increases (178 °C → 208 °C) and the chemical resistance improves (B → A).

[0057] From the comparison between Comparative Example 1 and Example 1, it can be seen that by changing the number of carbon atoms in the main chain of the methyl-branched aliphatic hydrocarbon group in the aliphatic diamine unit (B) from 5 (Comparative Example 1) to 8 (Example 1), the chemical resistance is significantly improved (C → A).

[0058] From the comparison between Comparative Example 2 and Example 1, it can be seen that by changing the number of carbon atoms in the main chain of the aliphatic diamine unit (B) from 3 (Comparative Example 2) to 8 (Example 1), the melting point is significantly lowered (226 °C → 208 °C), the occurrence of coloring is suppressed (C → A), and by changing the branch from an ethyl group (Comparative Example 2) to a methyl group (Example 1), the chemical resistance is improved (B → A).

Industrial Applicability

[0059] According to the present invention, it is possible to provide a thermoplastic polyurea excellent in chemical resistance and capable of suppressing coloring during melt molding, and a molded article containing the thermoplastic polyurea. The thermoplastic polyurea of the present invention can be used, for example, in various substrates of electronic components, housings of electronic components, cagings of electronic components, coverlays, wire coatings, laminated films, tubes for home appliances, industrial hydraulic belts, airless tires, inner liners for tires, seal members, diaphragms, wire cables, bearing retainers, hair dryers, bobbin cases, mixing faucets, medical catheters, display cover films, wearable devices, etc.

Claims

1. An aliphatic diamine unit (A) having a linear aliphatic hydrocarbon group and an aliphatic diamine unit (B) having a methyl-branched aliphatic hydrocarbon group with 7 to 12 carbon atoms in the main chain, and A thermoplastic polyurea in which the average number of carbon atoms of the linear aliphatic hydrocarbon group is 7 to 12.

2. The thermoplastic polyurea according to Claim 1, wherein the molar ratio (A / B) of the aliphatic diamine unit (A) to the aliphatic diamine unit (B) is 99 / 1 to 30 / 70.

3. The thermoplastic polyurea according to Claim 1 or 2, wherein the average number of carbon atoms of the linear aliphatic hydrocarbon group is 7 to 11.

4. The thermoplastic polyurea according to Claim 1 or 2, wherein the bonds between the aliphatic diamine unit (A) and the aliphatic diamine unit (B), the bonds between the aliphatic diamine units (A), and the bonds between the aliphatic diamine units (B) are urea bonds.

5. The thermoplastic polyurea according to Claim 1 or 2, wherein the carbonyl group in the urea bond of the thermoplastic polyurea is derived from urea.

6. The thermoplastic polyurea according to Claim 1 or 2, having a melting point of 220°C or lower.

7. A molded article containing the thermoplastic polyurea according to Claim 1 or 2.

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