Production method of crystalline polyamide resin

Abstract

There is provided a production method of a crystalline polyamide resin by thermal polycondensation of a mixture including at least a diamine component, a dicarboxylic acid component and water as a starting material, wherein the diamine component includes (A) pentamethylene diamine at a ratio that is equal to or greater than 10 mol % and less than 80 mol % relative to a gross amount of the diamine component; and the dicarboxylic acid component includes (B) at least one selected from the group consisting of an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid and dialkyl ester derivatives thereof at a ratio that is equal to or greater than 76 mol % and equal to or less than 100 mol % relative to a gross amount of the dicarboxylic acid component.

Claims

1. A production method of a crystalline polyamide resin by thermal polycondensation of a mixture including at least a diamine component, a dicarboxylic acid component and water as a starting material, wherein the diamine component includes (A) pentamethylene diamine at a ratio that is equal to or greater than 10 mol % and less than 80 mol % relative to a gross amount of the diamine component, and the dicarboxylic acid component includes (B) at least one selected from the group consisting of an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid and dialkyl ester derivatives thereof at a ratio that is equal to or greater than 76 mol % and equal to or less than 100 mol % relative to a gross amount of the dicarboxylic acid component, the production method comprising: a first step that heats the mixture, which has a water content equal to or less than 30% by weight, at a temperature equal to or higher than 200° C. under a pressure of 1.8 to 3.5 MPa to perform polycondensation with distillation of water; a second step that releases pressure to an atmospheric pressure level, subsequent to the first step; and a third step that continues thermal polycondensation subsequent to the second step, so as to obtain the crystalline polyamide resin, the third step performing high-degree melt polymerization at a temperature that is equal to or higher than a melting point of the crystalline polyamide resin until a relative viscosity at 25° C. of a solution prepared by dissolving the obtained crystalline polyamide resin at a concentration of 0.01 mg/mL in 98% sulfuric acid reaches between 1.8 and 3.5, wherein the crystalline polyamide resin has heat of fusion measured by using a differential scanning calorimeter, which is equal to or greater than 30 J/g when temperature is decreased from a molten state to 30° C. at a temperature decrease rate of 20° C./minute and is subsequently increased at a temperature increase rate of 20° C./minute.

2. The production method of the crystalline polyamide resin according to claim 1, wherein the crystalline polyamide resin has a temperature of an endothermic peak corresponding to the melting point measured by using a differential scanning calorimeter, which is equal to or higher than 270° C. when temperature is decreased from a molten state to 30° C. at a temperature decrease rate of 20° C./minute and is subsequently increased at a temperature increase rate of 20° C./minute.

3. The production method of the crystalline polyamide resin according to claim 1, wherein the temperature at the start of pressure relief is equal to or lower than 295° C., and the temperature at the end of pressure relief is equal to or higher than the melting point in the second step.

4. The production method of the crystalline polyamide resin according to claim 1, wherein the high-degree melt polymerization in the third step is performed under reduced pressure or under an inert gas atmosphere.

5. A crystalline polyamide resin produced by thermal polycondensation of at least a diamine component and a dicarboxylic acid component, wherein the diamine component includes (A) pentamethylene diamine at a ratio that is equal to or greater than 10 mol % and less than 80 mol % relative to a gross amount of the diamine component, and the dicarboxylic acid component includes (B) at least one selected from the group consisting of an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid and dialkyl ester derivatives thereof at a ratio that is equal to or greater than 76 mol % and equal to or less than 100 mol % relative to a gross amount of the dicarboxylic acid component, the crystalline polyamide resin having a relative viscosity between 1.8 and 3.5 at 25° C. of a solution prepared by dissolving the crystalline polyamide resin at a concentration of 0.01 mg/mL in 98% sulfuric acid, and having a degree of dispersion (weight-average molecular weight/number-average molecular weight) equal to or less than 3.5 measured by gel permeation chromatography, wherein the crystalline polyamide resin having heat of fusion measured by using a differential scanning calorimeter, which is equal to or greater than 30 J/g measured by using a differential scanning calorimeter when temperature is decreased from a molten state to 30° C. at a temperature decrease rate of 20° C./minute and is subsequently increased at a temperature increase rate of 20° C./minute.

6. The crystalline polyamide resin according to claim 5, wherein the crystalline polyamide resin having a temperature of an endothermic peak corresponding to a melting point measured by using a differential scanning calorimeter, which is equal to or higher than 270° C. when temperature is decreased from a molten state to 30° C. at a temperature decrease rate of 20° C./minute and is subsequently increased at a temperature increase rate of 20° C./minute.

7. The crystalline polyamide resin according to claim 5, wherein the crystalline polyamide resin having a piperidine content that is equal to or less than 10.0×10.sup.−5 mol/g.

8. The crystalline polyamide resin according to claim 5, wherein (B) the at least one selected from the group consisting of the aromatic dicarboxylic acid, the alicyclic dicarboxylic acid and the dialkyl ester derivatives thereof includes at least an aromatic dicarboxylic acid, and the aromatic dicarboxylic acid is terephthalic acid and/or isophthalic acid.

9. A molded product produced by molding the crystalline polyamide resin according to claim 5.

10. A polyamide resin composition produced by further adding an inorganic filler to the crystalline polyamide resin according to claim 5.

11. A molded product produced by molding the crystalline polyamide resin composition according to claim 10.

12. A polyamide resin composition produced by further adding an impact modifier to the crystalline polyamide resin according to claim 5.

13. A molded product produced by molding the crystalline polyamide resin composition according to claim 12.

Description

EXAMPLES

(1) The properties of the polyamide resins used in the respective examples and comparative examples were evaluated by the following methods.

(2) [Discharge Rate]

(3) The ratio of the yield actually discharged from a polymerization apparatus to the theoretical yield on the assumption that the polyamide resin raw material was fully polymerized was determined as the discharge rate.

(4) [Relative Viscosity (ηr)]

(5) The relative viscosity of the polyamide resin was measured at the concentration of 0.01 g/mL in 98% sulfuric acid at 25° C. by using an Ostwald viscometer.

(6) [Melting Point (Tm) and Heat of Fusion (ΔHm)]

(7) By using a robot DSC RDC 220 manufactured by Seiko Instruments Inc., about 5 mg of the polyamide resin was accurately weighed and was subjected to measurement in a nitrogen atmosphere under the following conditions. The polyamide resin was heated to (temperature (T.sub.o) of an endothermic peak+35° C.) to be in the molten state, wherein the endothermic peak was observed when the temperature was increased from 30° C. at a temperature increase rate of 20° C./minute. The temperature was then decreased to 30° C. at a temperature decrease rate of 20° C./minute and was kept at 30° C. for 3 minutes. The temperature (melting point: Tm) and the area (heat of fusion: ΔHm) of an endothermic peak was determined, wherein the endothermic peak was observed when the temperature was subsequently increased to T.sub.o+35° C. at a temperature increase rate of 20° C./minute. The area herein is defined as an area surrounded by connecting (Tm−45° C.) with (Tm+20° C.) on a DSC curve.

(8) [Content of piperidine or 3-methylpiperidine]

(9) About 0.06 g of the polyamide resin was accurately weighed and was subjected to hydrolysis in a hydrobromic acid aqueous solution at 150° C. for 3 hours. The treated solution was alkalified by addition of a 40% sodium hydroxide aqueous solution. After that, toluene and ethyl chloroformate were subsequently added to the solution, and the solution mixture was stirred. A supernatant toluene solution was extracted as a measurement solution. A piperidine standard solution or a 3-methyl piperidine standard solution was used for quantitative analysis. The following conditions were employed as measurement conditions:

(10) Instrument: GC-14A manufactured by SHIMADZU CORPORATION

(11) Column: NB-1 (manufactured by GL Sciences Inc.) 60 m×0.25 mm

(12) Detector: FID (flame ionization detector)

(13) Oven temperature: increasing from 150° C. to 330° C. at a rate of 10° C./minute

(14) Sample inlet temperature: 250° C.

(15) Detector temperature: 330° C.

(16) Carrier gas: He

(17) Sample injection volume: 3.0 μL

(18) [Number Average Molecular Weight (Mn), Weight Average Molecular Weight (Mw) and Degree of Dispersion (Mw/Mn)]

(19) A solution obtained by dissolution of 2.5 mg of the polyamide resin in 4 mL of hexafluoroisopropanol (with 0.005 N sodium trifluoroacetate added) and subsequent filtration with a filter of 0.45 μm was subjected to measurement using gel permeation chromatography (GPC). The following conditions were employed as measurement conditions:

(20) Instrument: e-Alliance GPC systems (e-alliance 2695XE separation module) (manufactured by Waters Corporation)

(21) Detector: 2414 differential refractometer (manufactured by Waters Corporation)

(22) Column: Shodex HFIP-806M (two columns)+HFIP-LG

(23) Solvent: hexafluoroisopropanol (with 0.005 N sodium trifluoroacetate added)

(24) Flow rate: 0.5 ml/minute

(25) Sample injection volume: 0.1 mL

(26) Temperature: 30° C.

(27) Molecular weight calibration: polymethyl methacrylate

(28) [Flexural Modulus]

(29) A rod-shaped test piece of ½ inch (1.27 cm)×5 inch (12.7 cm)×¼ inch (0.635 cm) obtained by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, Ltd.; cylinder temperature: melting point+15° C.; mold temperature: 150° C.; injection pressure: lower limit pressure+0.5 MPa) was subjected to a flexural test according to ASTM-D790.

(30) [Tensile Strength]

(31) An ASTM No. 1 dumbbell obtained by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, Ltd.; cylinder temperature: melting point+15° C.; mold temperature: 150° C.; injection pressure: lower limit pressure+0.5 MPa) was subjected to a tensile test according to ASTM-D638.

Reference Example 1 (Preparation of Lysine Decarboxylase)

(32) Lysine decarboxylase was prepared as described below, in order to produce pentamethylene diamine used for production of the polyamide resins of the respective examples and comparative examples. E. coli JM 109 strain was cultured by the following procedure. This strain was first inoculated with one platinum loop in 5 mL of an LB medium and was shaken at 30° C. for 24 hours for preculture. Then, 50 mL of the LB medium was placed into a 500 mL conical flask and preliminarily steam-sterilized at 115° C. for 10 minutes. The above precultured strain was then subcultured on this sterilized medium and was cultured under the conditions of the amplitude of 30 cm and at 180 rpm for 24 hours at pH adjusted to 6.0 with a 1 N hydrochloric acid aqueous solution. The resulting fungus bodies were collected, and a cell-free extract was prepared by ultrasonic grinding and centrifugation. The lysine decarboxylase activity of the cell-free extract was measured by a conventional method (Souda Kenji, Misono Haruo, Seikagaku jikken koza (biochemical experiment course) vol. 11-jo, page 179-191 (1976)). In the case of lysine substrate, there is a possibility of conversion by lysine monooxygenase, lysine oxydase and lysine mutase, which is expected to be intrinsically the main route in the lysine metabolic system of the above E. coli strain. For the purpose of blocking this reaction system, the cell-free extract of the E. coli JP 109 strain was heated at 75° C. for 5 minutes. This cell-free extract was then fractionated with 40% saturated ammonium sulfate and 55% saturated ammonium sulfate. By using the obtained crude lysine decarboxylase solution, pentamethylene diamine was produced from lysine.

Reference Example 2 (Production of Pentamethylene Diamine)

(33) An aqueous solution was prepared to include 50 mM of lysine hydrochloride (manufactured by Wako Pure Chemical Industries, Ltd.), 0.1 mM of pyridoxal phosphate (manufactured by Wako Pure Chemical Industries, Ltd.) and 40 mg/L of crude lysine decarboxylase (produced in Reference Example 1). Pentamethylene diamine hydrochloride was obtained by reaction of 1000 mL of the aqueous solution at 45° C. for 48 hours at pH maintained at 5.5 to 6.5 with a 0.1 N hydrochloric acid aqueous solution. The pentamethylene diamine hydrochloride was converted to pentamethylene diamine by adding sodium hydroxide to this aqueous solution, was extracted with chloroform and was subjected to distillation under reduced pressure (10 mmHg, 60° C.). This yielded pentamethylene diamine. This pentamethylene diamine was detected to include no 2,3,4,5-tetrahydropyridine or piperidine as impurities.

Example 1

(34) In a 30 L pressure vessel with a stirrer, 2.00 kg of pentamethylene diamine (Reference Example 2), 2.16 kg of hexamethylene diamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 6.04 kg of terephthalic acid (manufactured by Mitsui Chemicals, Inc.), 4.3 g of sodium hypophosphite monohydrate (manufactured by Kanto Chemical Co., Inc.) and 3.3 kg of ion exchange water were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 236° C. and the internal pressure reached 2.2 MPa, the internal pressure was maintained at 2.2 MPa for 124 minutes accompanied with distillation of water vapor. When the internal temperature reached 290° C., the internal pressure was released to the ordinary pressure over 90 minutes (internal temperature eventually reached 317° C.). Polymerization was then continued for 15 minutes under reduced pressure (40 kPa), so that a polyamide resin was obtained. The reaction proceeds in the closed system for a time period between the supply of the raw materials and the start of pressure relief, so that the water content at the time of application of heat and pressure is equal to the water content at the time of material supply. The maximum temperature during polymerization was 325° C.

Example 2

(35) A polyamide resin was obtained by the same procedure as Example 1, except that the internal pressure was changed to 2.5 MPa. The temperature at the end of pressure relief was 328° C., and the maximum temperature was 334° C.

Example 3

(36) A polyamide resin was obtained by the same procedure as Example 2, except that the temperature at the start of pressure relief was changed to 300° C. The temperature at the end of pressure relief was 319° C., and the maximum temperature was 325° C.

Example 4

(37) A polyamide resin was obtained by the same procedure as Example 1, except that the internal pressure was changed to 2.0 MPa. The temperature at the end of pressure relief was 314° C., and the maximum temperature was 325° C.

Example 5

(38) A polyamide resin was obtained by the same procedure as Example 1, except that the internal pressure was changed to 2.8 MPa. The temperature at the end of pressure relief was 317° C., and the maximum temperature was 328° C.

Comparative Example 1

(39) A polyamide resin was obtained by the same procedure as Example 1, except that the internal pressure was changed to 1.7 MPa. The temperature at the end of pressure relief was 321° C., and the maximum temperature was 330° C.

Comparative Example 2

(40) A polyamide resin was obtained by the same procedure as Example 1, except that the internal pressure was changed to 3.7 MPa. The temperature at the end of pressure relief was 320° C., and the maximum temperature was 329° C.

Comparative Example 3

(41) A polyamide resin was obtained by the same procedure as Example 2, except that the amount of ion exchange water was changed to 10 kg. The temperature at the end of pressure relief was 323° C., and the maximum temperature was 330° C.

Comparative Example 4

(42) In a 30 L pressure vessel with a stirrer, the same raw materials as those of Example 1 were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 240° C. and the internal pressure reached 2.5 MPa, the internal pressure was maintained at 2.5 MPa for 120 minutes accompanied with distillation of water vapor (the internal temperature eventually reached 290° C.). The content was discharged from the reaction vessel onto a cooling belt. A low-degree condensation product obtained by vacuum drying this content at 120° C. for 24 hours was subjected to solid-phase polymerization at 240° C. under reduced pressure (40 Pa), so that a polyamide resin was obtained.

Comparative Example 5

(43) In a 30 L pressure vessel with a stirrer, 2.16 kg of 2-methylpentamethylene diamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 2.16 kg of hexamethylene diamine, 5.88 kg of terephthalic acid, 4.3 g of sodium hypophosphite monohydrate and 3.3 kg of ion exchange water as the raw materials were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 226° C. and the internal pressure reached 1.7 MPa, the internal pressure was maintained at 1.7 MPa for 140 minutes accompanied with distillation of water vapor. When the internal temperature reached 290° C., the internal pressure was released to the ordinary pressure over 90 minutes (internal temperature eventually reached 321° C.). Polymerization was then continued for 15 minutes under reduced pressure (40 kPa), so that a polyamide resin was obtained. The maximum temperature during polymerization was 325° C.

Example 6

(44) In a 3 L pressure vessel with a stirrer, 114 g of pentamethylene diamine, 242 g of diaminodecane (manufactured by Kokura Synthetic Industries, Ltd.), 407 g of terephthalic acid, 0.1655 g of sodium hypophosphite monohydrate and 250 g of ion exchange water were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 243° C. and the internal pressure reached 2.5 MPa, the internal pressure was maintained at 2.5 MPa for 46 minutes accompanied with distillation of water vapor. When the internal temperature reached 275° C., the internal pressure was released to the ordinary pressure over 60 minutes (internal temperature eventually reached 310° C.). Polymerization was then continued for 15 minutes under a nitrogen atmosphere (0.5 L/min), so that a polyamide resin was obtained. The reaction proceeds in the closed system for a time period between the supply of the raw materials and the start of pressure relief, so that the water content at the time of application of heat and pressure is equal to the water content at the time of material supply. The maximum temperature during polymerization was 314° C.

Example 7

(45) In a 3 L pressure vessel with a stirrer, 114 g of pentamethylene diamine, 260 g of diaminododecane (manufactured by Kokura Synthetic Industries, Ltd.), 390 g of terephthalic acid, 0.1664 g of sodium hypophosphite monohydrate and 250 g of ion exchange water were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 243° C. and the internal pressure reached 2.5 MPa, the internal pressure was maintained at 2.5 MPa for 50 minutes accompanied with distillation of water vapor. When the internal temperature reached 270° C., the internal pressure was released to the ordinary pressure over 60 minutes (internal temperature eventually reached 300° C.). Polymerization was then continued for 15 minutes under a nitrogen atmosphere (0.5 L/min), so that a polyamide resin was obtained. The reaction proceeds in the closed system for a time period between the supply of the raw materials and the start of pressure relief, so that the water content at the time of application of heat and pressure is equal to the water content at the time of material supply. The maximum temperature during polymerization was 305° C.

Comparative Example 6

(46) Polymerization was performed by the same procedure as that of Example 6, except that 123 g of hexamethylene diamine, 241 g of diaminodecane, 397 g of terephthalic acid, 0.1660 g of sodium hypophosphite monohydrate and 250 g of ion exchange water were used as the raw materials. In the course of polymerization, however, the polymer was gelated and could not thus be discharged. The temperature at the end of pressure relief was 294° C., and the maximum temperature was 303° C.

Comparative Example 7

(47) Polymerization was performed by the same procedure as that of Example 7, except that 123 g of hexamethylene diamine, 260 g of diaminododecane, 381 g of terephthalic acid, 0.1669 g of sodium hypophosphite monohydrate and 250 g of ion exchange water were used as the raw materials. In the course of polymerization, however, the polymer was gelated and could not thus be discharged. The temperature at the end of pressure relief was 293° C., and the maximum temperature was 300° C.

Comparative Example 8

(48) A polyamide resin was obtained by the same procedure as Example 6, except that the internal pressure was changed to 1.7 MPa. The temperature at the end of pressure relief was 305° C., and the maximum temperature was 308° C.

(49) The conditions of manufacturing the polyamide resins of Examples 1 to 7 and Comparative Examples 1 to 8 and the measurement results of the respective polyamide resins are summarized in Tables 1 to 4 given below. Polycondensation of the diamine component and the dicarboxylic acid component herein is sequential polymerization. Since the polyamide resin of each Example has an increased relative viscosity which corresponds to the degree of polymerization, it is expected that the composition of the polyamide resin of each Example is substantially equivalent to the composition based on the feeding amounts of the raw materials.

(50) TABLE-US-00001 TABLE 1 EX 1 EX 2 EX 3 EX 4 weight ratio 5T/6T = 5T/6T = 5T/6T = 5T/6T = Polymer Composition 50/50 50/50 50/50 50/50 Ratio of (A) to Gross mol % 51.3 51.3 51.3 51.3 Amount of Diamine Component Ratio of (B) to Gross mol % 100 100 100 100 Amount of Dicarboxylic Acid Component Water Content At Start wt % 24 24 24 24 of Application of Heat and Pressure Pressure MPa 2.2 2.5 2.5 2.0 Temperature at Start ° C. 290 290 300 290 of Pressure Relief Temperature at End ° C. 317 328 319 314 of Pressure Relief Maximum Temperature ° C. 325 334 325 325 Discharge Rate wt % 95 93 95 85 ηr — 2.0 2.2 1.8 2.0 Piperidine ×10.sup.−5 mol/g 6.4 6.6 22 5.7 Tm ° C. 309 311 308 308 ΔHm J/g 41 38 36 39 Mn — 10400 10100 6000 9450 Mw — 27300 33900 20700 27400 Mw/Mn — 2.63 3.36 3.45 2.90 5T: Structural unit consisting of pentamethylene diamine and terephthalic acid 6T: Structural unit consisting of hexamethylene diamine and terephthalic acid

(51) TABLE-US-00002 TABLE 2 EX 5 EX 6 EX 7 weight ratio 5T/6T = 5T/10T = 5T/12T = Polymer Composition 50/50 40/60 40/60 Ratio of (A) to Gross mol % 51.3 44.4 46.3 Amount of Diamine Component Ratio of (B) to Gross mol % 100 100 100 Amount of Dicarboxylic Acid Component Water Content At Start wt % 24 25 25 of Application of Heat and Pressure Pressure MPa 2.8 2.5 2.5 Temperature at Start ° C. 290 275 270 of Pressure Relief Temperature at End ° C. 317 310 300 of Pressure Relief Maximum ° C. 328 314 305 Temperature Discharge Rate wt % 95 92 95 ηr — 1.8 2.8 2.5 Piperidine ×10.sup.−5 mol/g 14 7.0 6.7 Tm ° C. 307 278 273 ΔHm J/g 38 40 32 Mn — 6330 12800 11000 Mw — 21000 38800 32700 Mw/Mn — 3.32 3.03 2.97 5T: Structural unit consisting of pentamethylene diamine and terephthalic acid 6T: Structural unit consisting of hexamethylene diamine and terephthalic acid 10T: Structural unit consisting of decane diamine and terephthalic acid 12T: Structural unit consisting of dodecane diamine and terephthalic acid

(52) TABLE-US-00003 TABLE 3 COMP COMP COMP COMP EX 1 EX 2 EX 3 EX 4 weight ratio 5T/6T = 5T/6T = 5T/6T = 5T/6T = Polymer Composition 50/50 50/50 50/50 50/50 Ratio of (A) to mol % 51.3 51.3 51.3 51.3 Gross Amount of Diamine Component Ratio of (B) to mol % 100 100 100 100 Gross Amount of Dicarboxylic Acid Component Water Content wt % 24 24 49 24 At Start of Application of Heat and Pressure Pressure MPa 1.7 3.7 2.5 2.5 Temperature ° C. 290 290 290 290 at Start of Pressure Relief Temperature ° C. 321 320 323 — at End of Pressure Relief Maximum ° C. 330 329 330 — Temperature Discharge Rate wt % 10 98 99 99 ηr — 1.7 1.4 1.4 2.1 (Solid phase polymer- ization) Piperidine ×10.sup.−5 5.5 33 38 6.0 mol/g Tm ° C. 308 307 307 312 ΔHm J/g 40 38 38 43 Mn — 7280 4450 4490 7820 Mw — 18700 7690 7400 31500 Mw/Mn — 2.57 1.73 1.65 4.03 5T: Structural unit consisting of pentamethylene diamine and terephthalic acid 6T: Structural unit consisting of hexamethylene diamine and terephthalic acid

(53) TABLE-US-00004 TABLE 4 COMP COMP COMP COMP EX 5 EX 6 EX 7 EX 8 weight ratio M5T/6T = 6T/10T = 6T/12T = 5T/10T = Polymer Composition 50/50 40/60 40/60 40/60 Ratio of (A) to Gross mol % 0 0 0 44.4 Amount of Diamine Component Ratio of (B) to Gross mol % 100 100 100 100 Amount of Dicarboxylic Acid Component Water Content At Start wt % 24 25 25 25 of Application of Heat and Pressure Pressure MPa 1.7 2.5 2.5 1.7 Temperature at Start ° C. 290 275 270 275 of Pressure Relief Temperature at End ° C. 321 294 293 305 of Pressure Relief Maximum Temperature ° C. 325 303 300 308 Discharge Rate wt % 95 0 0 13 ηr — 2.1 — — 1.6 Piperidine ×10.sup.−5 mol/g — — — 6.2 3-Methyl piperidine ×10.sup.−5 mol/g 5.7 — — — Tm ° C. 303 — — 276 ΔHm J/g 28 — — 41 Mn — 10700 — — 8370 Mw — 31700 — — 22600 Mw/Mn — 2.96 — — 2.70 M5T: Structural unit consisting of 2-methylpentamethylene diamine and terephthalic acid 6T: Structural unit consisting of hexamethylene diamine and terephthalic acid 10T: Structural unit consisting of decane diamine and terephthalic acid 12T: Structural unit consisting of dodecane diamine and terephthalic acid

(54) According to comparison between Examples 1 to 6 and Comparative Examples 1 and 8, it is concluded that the polymerization pressure is to be controlled to or above 1.8 MPa, in order to ensure 85% or a higher yield of the polyamide resin relative to the theoretical yield. In Comparative Examples 1 and 8, a temporary abrupt increase of the stirring torque was observed, while the internal pressure was maintained at 1.7 MPa. In Comparative Examples 1 and 8, it is accordingly estimated that about 90% of the polymer was not dischargeable since polymer precipitated in the state wound on the mixing blade in the course of polymerization.

(55) According to comparison between Examples 1, 2, 4 and 5 and Comparative Example 2, it is shown that an increase in polymerization pressure leads to an increase in piperidine content in the polyamide resin and makes high polymerization of the polyamide resin difficult. It is accordingly concluded that the polymerization pressure is to be controlled to or below 3.5 MPa.

(56) According to comparison between Examples 2 and 3, it is concluded that controlling the temperature at the start of pressure relief to or below 290° C. significantly reduces the piperidine content.

(57) According to comparison between Examples 2 and Comparative Example 3, it is shown that an increase in water content in the raw materials leads to an increase in piperidine content when the raw materials are heated to or above 200° C. without concentration of the raw materials at the temperature of lower than 200° C. It is accordingly concluded that the water content in the raw materials is to be controlled to or below 30% by weight.

(58) According to comparison between Examples 1 to 5 and Comparative Example 4, it is shown that the degree of dispersion (weight-average molecular weight/number-average molecular weight) representing a distribution of the molecular weight of the polyamide resin obtained by melt polymerization has the smaller value, which indicates the more homogeneous polymer, compared with that of the polyamide resin obtained by solid phase polymerization.

(59) According to comparison between Examples 1 and 4, it is shown that Example 1 having the polymerization pressure of 2.2 MPa during distillation of water under application of heat and pressure has the higher discharge rate than that of Example 4 having the above pressure of 2.0 MPa. It is thus expected that an increase in polymerization pressure more effectively suppresses precipitation of polymer in the course of polymerization.

(60) According to comparison between Comparative Examples 1 and 5, it is shown that 95% of the theoretical yield is dischargeable even under the polymerization pressure of 1.7 MPa when 2-methylpentamethylene diamine is used in place of pentamethylene diamine.

(61) According to comparison between Examples 6 and 7 and Comparative Examples 6 and 7, it is showed that the polymer is gelated in the course of polymerization when hexamethylene diamine is used in place of pentamethylene diamine.

(62) The following evaluation criteria are employed to discriminate precipitation of polymer in the course of polymerization from gelation:

(63) Precipitation of polymer in the course of polymerization: The polymer that is not dischargeable but remains in the pressure vessel after completion of polymerization is partly dischargeable when being kept at the temperature of or above the melting point for a long time (Comparative Example 1).

(64) Gelation: The polymer that is not dischargeable but remains in the pressure vessel after completion of polymerization is not dischargeable even when being kept at the temperature of or above the melting point for a long time (Comparative Examples 6 and 7).

Example 8

(65) In a 3 L pressure vessel with a stirrer, 112 g of pentamethylene diamine, 229 g of diaminodecane, 413 g of 1,4-cyclohexane dicarboxylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 250 g of ion exchange water were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 245° C. and the internal pressure reached 2.5 MPa, the internal pressure was maintained at 2.5 MPa for 50 minutes accompanied with distillation of water vapor. When the internal temperature reached 280° C., the internal pressure was released to the ordinary pressure over 60 minutes (internal temperature eventually reached 305° C.). Polymerization was then continued for 15 minutes under reduced pressure (40 kPa), so that a polyamide resin was obtained. The reaction proceeds in the closed system for a time period between the supply of the raw materials and the start of pressure relief, so that the water content at the time of application of heat and pressure is equal to the water content at the time of material supply. The maximum temperature during polymerization was 310° C.

Example 9

(66) In a 3 L pressure vessel with a stirrer, 112 g of pentamethylene diamine, 246 g of diaminododecane, 396 g of 1,4-cyclohexane dicarboxylic acid and 250 g of ion exchange water were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 245° C. and the internal pressure reached 2.5 MPa, the internal pressure was maintained at 2.5 MPa for 40 minutes accompanied with distillation of water vapor. When the internal temperature reached 270° C., the internal pressure was released to the ordinary pressure over 60 minutes (internal temperature eventually reached 298° C.). Polymerization was then continued for 15 minutes under reduced pressure (40 kPa), so that a polyamide resin was obtained. The reaction proceeds in the closed system for a time period between the supply of the raw materials and the start of pressure relief, so that the water content at the time of application of heat and pressure is equal to the water content at the time of material supply. The maximum temperature during polymerization was 303° C.

Example 10

(67) In a 3 L pressure vessel with a stirrer, 135 g of pentamethylene diamine, 146 g of hexamethylene diamine, 408 g of terephthalic acid, 75 g of 12-aminododecanoic acid, 0.3277 g of sodium hypophosphite monohydrate and 250 g of ion exchange water were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 237° C. and the internal pressure reached 2.2 MPa, the internal pressure was maintained at 2.2 MPa for 50 minutes accompanied with distillation of water vapor. When the internal temperature reached 280° C., the internal pressure was released to the ordinary pressure over 60 minutes (internal temperature eventually reached 320° C.). Polymerization was then continued for 15 minutes under reduced pressure (40 kPa), so that a polyamide resin was obtained. The reaction proceeds in the closed system for a time period between the supply of the raw materials and the start of pressure relief, so that the water content at the time of application of heat and pressure is equal to the water content at the time of material supply. The maximum temperature during polymerization was 325° C.

Example 11

(68) In a 3 L pressure vessel with a stirrer, 165 g of pentamethylene diamine, 146 g of hexamethylene diamine, 408 g of terephthalic acid, 44 g of adipic acid, 0.3254 g of sodium hypophosphite monohydrate and 250 g of ion exchange water were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 236° C. and the internal pressure reached 2.2 MPa, the internal pressure was maintained at 2.2 MPa for 50 minutes accompanied with distillation of water vapor. When the internal temperature reached 280° C., the internal pressure was released to the ordinary pressure over 60 minutes (internal temperature eventually reached 313° C.). Polymerization was then continued for 15 minutes under reduced pressure (40 kPa), so that a polyamide resin was obtained. The reaction proceeds in the closed system for a time period between the supply of the raw materials and the start of pressure relief, so that the water content at the time of application of heat and pressure is equal to the water content at the time of material supply. The maximum temperature during polymerization was 322° C. The composition (weight ratio) of the polyamide resin of this Example may be expressed from the supply amounts of the raw materials as 5T/6T/56=45/45/10 as shown in Table 5 given below (wherein 5T represents a structural unit consisting of pentamethylene diamine and terephthalic acid; 6T represents a structural unit consisting of hexamethylene diamine and terephthalic acid; and 56 represents a structural unit consisting of pentamethylene diamine and adipic acid). Since the respective raw materials are polymerized at random, it is estimated that the polyamide resin actually obtained also includes a structural unit consisting of hexamethylene diamine and adipic acid.

Comparative Example 9

(69) A polyamide resin was obtained by the same procedure as Example 8, except that the internal pressure was changed to 1.7 MPa and the temperature at the start of pressure relief was changed to 284° C. The temperature at the end of pressure relief was 303° C., and the maximum temperature was 305° C.

Comparative Example 10

(70) In a 3 L pressure vessel with a stirrer, 272 g of pentamethylene diamine, 232 g of terephthalic acid, 249 g of sebacic acid (manufactured by Kokura Synthetic Industries, Ltd.) and 250 g of ion exchange water were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 227° C. and the internal pressure reached 1.7 MPa, the internal pressure was maintained at 1.7 MPa for 59 minutes accompanied with distillation of water vapor. When the internal temperature reached 248° C., the internal pressure was released to the ordinary pressure over 60 minutes (internal temperature eventually reached 282° C.). Polymerization was then continued for 15 minutes under reduced pressure (40 kPa), so that a polyamide resin was obtained. The reaction proceeds in the closed system for a time period between the supply of the raw materials and the start of pressure relief, so that the water content at the time of application of heat and pressure is equal to the water content at the time of material supply. The maximum temperature during polymerization was 285° C.

Comparative Example 11

(71) In a 3 L pressure vessel with a stirrer, 283 g of pentamethylene diamine, 325 g of terephthalic acid, 149 g of sebacic acid and 250 g of ion exchange water were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 245° C. and the internal pressure reached 2.5 MPa, the internal pressure was maintained at 2.5 MPa for 60 minutes accompanied with distillation of water vapor. When the internal temperature reached 290° C., the internal pressure was released to the ordinary pressure over 60 minutes (internal temperature eventually reached 325° C.). Polymerization was then continued for 15 minutes under reduced pressure (40 kPa), so that a polyamide resin was obtained. The reaction proceeds in the closed system for a time period between the supply of the raw materials and the start of pressure relief, so that the water content at the time of application of heat and pressure is equal to the water content at the time of material supply. The maximum temperature during polymerization was 330° C.

Comparative Example 12

(72) In a 3 L pressure vessel with a stirrer, 297 g of pentamethylene diamine, 235 g of 1,4-cyclohexane dicarboxylic acid, 221 g of adipic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 250 g of ion exchange water were supplied, were sealed and were subjected to nitrogen substitution. The mixture was heated with stirring. After the internal temperature reached 228° C. and the internal pressure reached 1.7 MPa, the internal pressure was maintained at 1.7 MPa for 62 minutes accompanied with distillation of water vapor. When the internal temperature reached 245° C., the internal pressure was released to the ordinary pressure over 60 minutes (internal temperature eventually reached 280° C.). Polymerization was then continued for 15 minutes under reduced pressure (40 kPa), so that a polyamide resin was obtained. The reaction proceeds in the closed system for a time period between the supply of the raw materials and the start of pressure relief, so that the water content at the time of application of heat and pressure is equal to the water content at the time of material supply. The maximum temperature during polymerization was 282° C.

(73) The conditions of manufacturing the polyamide resins of Examples 8 to 11 and Comparative Examples 9 to 12 and the measurement results of the respective polyamide resins are summarized in Tables 5 and 6 given below.

(74) TABLE-US-00005 TABLE 5 EX 8 EX 9 EX 10 EX 11 weight ratio 5C/10C = 5C/12C = 5T/6T 5T/6T /12 = /56 = Polymer Composition 40/60 50/60 45/45/10 45/45/10 Ratio of (A) to mol % 45.3 47.2 51.3 56.2 Gross Amount of Diamine Component Ratio of (B) to mol % 100 100 100 89.1 Gross Amount of Dicarboxylic Acid Component Water Content wt % 25 25 25 25 At Start of Application of Heat and Pressure Pressure MPa 2.5 2.5 2.2 2.2 Temperature ° C. 280 270 280 280 at Start of Pressure Relief Temperature ° C. 305 298 320 313 at End of Pressure Relief Maximum ° C. 310 303 325 322 Temperature Discharge Rate wt % 95 99 98 99 ηr — 3.1 2.8 2.4 2.3 Piperidine ×10.sup.−5 6.5 6.1 7.9 7.8 mol/g Tm ° C. 292 272 300 295 ΔHm J/g 32 30 33 35 Mn — 13100 12100 13900 12000 Mw — 61800 39200 41200 37900 Mw/Mn — 3.19 3.24 2.96 3.16 5T: Structural unit consisting of pentamethylene diamine and terephthalic acid 6T: Structural unit consisting of hexamethylene diamine and terephthalic acid 5C: Structural unit consisting of pentamethylene diamine and 1,4-cyclohexane dicarboxylic acid 10C: Structural unit consisting of decane diamine and 1,4-cyclohexane dicarboxylic acid 12C: Structural unit consisting of dodecene diamine and 1,4-cyclohexane dicarboxylic acid 12: Structural unit consisting of aminododecene acid 56: Structural unit consisting of pentamethylene diamine and adipic acid

(75) TABLE-US-00006 TABLE 6 COMP COMP COMP COMP EX 9 EX 10 EX 11 EX 12 weight ratio 5C/10C = 5T/510 = 5T/510 = 5C/56 = Polymer Composition 40/60 50/50 70/30 50/50 Ratio of (A) to Gross mol % 45.3 100 100 100 Amount of Diamine Component Ratio of (B) to Gross mol % 100 53.1 72.6 47.4 Amount of Dicarboxylic Acid Component Water Content At Start wt % 25 25 25 25 of Application of Heat and Pressure Pressure MPa 1.7 1.7 2.5 1.7 Temperature at Start ° C. 284 248 290 245 of Pressure Relief Temperature at End ° C. 303 282 325 280 of Pressure Relief Maximum Temperature ° C. 305 285 330 282 Discharge Rate wt % 16 99 90 99 ηr — 1.6 2.9 2.3 2.8 Piperidine ×10.sup.−5 mol/g 5.7 3.9 4.5 3.2 Tm ° C. 270 253 314 259 ΔHm J/g 32 13 27 7 Mn — 9250 11900 7930 18800 Mw — 24800 34000 23000 54800 Mw/Mn — 2.68 2.86 2.90 2.91 5T: Structural unit consisting of pentamethylene diamine and terephthalic acid 5C: Structural unit consisting of pentamethylene diamine and 1,4-cyclohexane dicarboxylic acid 10C: Structural unit consisting of decane diamine and 1,4-cyclohexanone dicarboxylic acid 56: Structural unit consisting of pentamethylene diamine and adipic acid 510: Structural unit consisting of pentamethylene diamine and sebacic acid

(76) According to comparison between Example 8 and Comparative Example 9, it is concluded that the polymerization pressure of 2.5 MPa ensures the discharge rate of or above 95%. In Comparative Example 9, a temporary abrupt increase of the stirring torque was observed, while the internal pressure was maintained at 1.7 MPa. In Comparative Example 9, it is accordingly estimated that about 84% of the polymer was not dischargeable since polymer precipitated in the state wound on the mixing blade in the course of polymerization.

(77) According to Examples 10 and 11, it is shown that the polyamide resin having the excellent crystallinity (the large ΔHm) is obtainable even when a small amount of aminocarboxylic acid or adipic acid is copolymerized as the copolymerizable component.

(78) According to Comparative Examples 10 to 12, it is shown that the polyamide resin having the excellent heat resistance and the excellent crystallinity is not obtainable at the small ratio of the (B) component relative to the gross amount of the dicarboxylic acid component.

Examples 12 to 17, Comparative Examples 13 to 17

(79) Using a twin-screw extruder (TEX 30 manufactured by the Japan Steel Works, Ltd.) set to the cylinder temperature of 320° C. (295° C. only for Example 15) and the screw rotation speed of 150 rpm, a polyamide resin and an antioxidant were supplied from a main feeder and glass fibers, carbon fibers or an impact modifier were supplied from a side feeder at the composition shown in Tables 7 to 9 and melt kneaded. The polyamide resin and the antioxidant were pre-blended prior to the use. The extruded guts were pelletized, were vacuum dried at 120° C. for 24 hours, were injection molded (mold temperature: 150° C., but 140° C. only for Example 15) and were evaluated for mechanical properties.

(80) The following glass fibers and the antioxidant were used:

(81) Glass fibers: T289 manufactured by Nippon Electric Glass Co., Ltd.

(82) Carbon fibers: TV 14-006 manufactured by Toray Industries, Inc.

(83) Impact modifier: Tafmer MH 7020 manufactured by Mitsui Chemicals, Inc.

(84) Antioxidant: Irganox 1098

(85) (N,N′-hexamethylene-bis(3,5-di-t-butyl-4-hydroxyhydrocinnamide) manufactured by BASF SE

(86) The conditions of manufacturing the polyamide resin compositions of Examples 12 to 17 and Comparative Examples 13 to 17 and the measurement results of the flexural modulus and the tensile strength of the respective polyamide resin compositions are summarized in Tables 7 to 9 given below.

(87) TABLE-US-00007 TABLE 7 EX 12 EX 13 EX 14 EX 15 5T/6T = 50/50 parts by weight 100 100 100 0 (EX 2) 5T/10T = 40/60 parts by weight 0 0 0 100 (EX 6) 5T/6T = 50/50 parts by weight 0 0 0 0 (COMP EX 4) Glass fibers parts by weight 53.8 100 0 53.8 Carbon fibers parts by weight 0 0 53.8 0 Antioxident parts by weight 0.5 0.5 0 0 Flexural modulus GPa 11.5 15.1 20.8 10.3 Tensile strength MPa 210 248 187 204 5T: Structural unit consisting of pentamethylene diamine and terephthalic acid 6T: Structural unit consisting of hexamethylene diamine and terephthalic acid 10T: Structural unit consisting of decane diamine and terephalic acid

(88) TABLE-US-00008 TABLE 8 COMP COMP COMP EX 13 EX 14 EX 15 5T/6T = 50/50 (EX 2) parts by weight 0 0 0 5T/6T = 50/50 parts by weight 100 100 100 (COMP EX 4) Glass fibers parts by weight 53.8 100 0 Carbon fibers parts by weight 0 0 53.8 Antioxident parts by weight 0.5 0.5 0 Flexural modulus GPa 10.7 14.2 19.2 Tensile strength MPa 195 233 177 5T: Structural unit consisting of pentamethylene diamine and terephthalic acid 6T: Structural unit consisting of hexamethylene diamine and terephthalic acid

(89) TABLE-US-00009 TABLE 9 COMP COMP EX 16 EX 17 EX 16 EX 17 5T/6T = 50/50 parts by weight 100 100 0 0 (EX 2) 5T/6T = 50/50 parts by weight 0 0 100 100 (COMP EX 4) Impact modifier parts by weight 11.1 25 11.1 25 Antioxidant parts by weight 0.5 0.5 0.5 0.5 Flexural modulus GPa 2.45 2.01 2.33 1.95 Tensile strength MPa 81 65 77 60 5T: Structural unit consisting of pentamethylene diamine and terephthalic acid 6T: Structural unit consisting of hexamethylene diamine and terephthalic acid

(90) According to comparison between Examples 12 to 14 and Examples 16 and 17 and Comparative Examples 13 to 17, it is concluded that the polyamide resin composition using the polyamide resin obtained by melt polymerization has the better flexural modulus and the better tensile strength than those of the polyamide resin composition using the polyamide resin obtained by solid phase polymerization.

INDUSTRIAL APPLICABILITY

(91) The crystalline polyamide resin of the invention is preferably used for various applications such as electric and electronic-related parts, automobile and vehicle-related parts, household and office electric appliance-related parts, computer-related parts, facsimile and copying machine-related parts, machine-related parts, fibers and films.