MULTIMODAL POLYETHYLENE SCREW CAP

Abstract

The present invention relates to a reactor system for a multimodal polyethylene composition comprising; (a) first reactor (b) hydrogen removal unit arranged between the first reactor and a second reactor comprising at least one vessel connected with a depressurization equipment, preferably selected from vacuum pump, compressor, blower, ejector or a combination thereof, the depressurization equipment allowing to adjust an operating pressure to a pressure in a range of 100-200 kPa (abs); (c) the second reactor; and (d) a third reactor, a multimodal, polyethylene composition obtainable this way and a screw cap comprising the same.

Claims

1. A reactor system for a multimodal polyethylene polymerization process, comprising; (a) a first reactor; (b) a hydrogen removal unit arranged between the first reactor and a second reactor comprising at least one vessel connected with a depressurization equipment, preferably selected from vacuum pump, compressor, blower, ejector or a combination thereof, the depressurization equipment allowing to adjust an operating pressure to a pressure in a range of 100-200 kPa (abs); (c) the second reactor; and (d) a third reactor.

2. The reactor system according to claim 1, wherein the depressurization equipment allows to adjust the operating pressure in the hydrogen removal unit to a pressure in the range of 103-145 kPa (abs), preferably 104-130 kPa (abs), most preferably 105 to 115 kPa (abs).

3. The reactor system according to claim 1, wherein the hydrogen removal unit further contains a stripping column for the separation of hydrogen and a liquid diluent.

4. A process for producing a multimodal polyethylene composition in the reactor system according to claim 1, comprising; (a) polymerizing ethylene in an inert hydrocarbon medium in the first reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen in an amount of 0.1-95% by mol with respect to the total gas present in the vapor phase in the first reactor to obtain a low molecular weight polyethylene having a weight average molecular weight (Mw) of 20,000 to 90,000 g/mol or a medium molecular weight polyethylene having a weight average molecular weight (Mw) of more than 90,000 to 150,000 g/mol wherein the low molecular weight polyethylene, respectively the medium molecular weight polyethylene, has a density at least 0.965 g/cm3, and the low molecular weight polyethylene has MI2 in the range from 10 to 1,000 g/10 min and the medium molecular weight polyethylene has MI2 in the range from 0.1 to 10 g/10 min; (b) removing in the hydrogen removal unit 98.0 to 99.8% by weight of the hydrogen from a slurry mixture obtained from the first reactor at a pressure in the range of 103-145 kPa (abs) and transferring the obtained residual mixture to the second reactor; (c) polymerizing ethylene and optionally C.sub.4-12 -olefin comonomer in the second reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and in the presence of hydrogen in an amount obtained in step (b) to obtain a first high molecular weight polyethylene or a first ultra high molecular weight polyethylene in the form of a homopolymer or a copolymer and transferring a resultant mixture to the third reactor; and (d) polymerizing ethylene, and optionally C.sub.4-12 -olefin comonomer in the third reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen, wherein the amount of hydrogen in the third reactor is in a range of 0.1-70% by mol, preferably 0.1-60% by mol, with respect to the total gas present in the vapor phase in the third reactor or optionally substantial absence of hydrogen to obtain a second high molecular weight polyethylene or a second ultra high molecular weight polyethylene homopolymer or copolymer.

5. The process according to claim 4, wherein the removing is removing of 98.0-99.8% by weight of the hydrogen, more preferable 98.0-99.5% by weight, and most preferred 98.0 to 99.1% by weight.

6. The process according to claim 4, wherein the operation pressure in the hydrogen removal unit is in the range of 103-145 kPa (abs), more preferably 104-130 kPa (abs), and most preferred 105 to 115 kPa (abs).

7. A multimodal polyethylene composition obtainable by a process according to claim 4, comprising; (A) 30 to 65 parts by weight, preferably 45 to 65 parts by weight, most preferred 50 to 60 parts by weight, of the low molecular weight polyethylene having a weight average molecular weight (Mw) of 20,000 to 90,000 g/mol; (B) 5 to 40 parts by weight, preferably 5 to 30 parts by weight, most preferred 5 to 20 parts by weight, of the first high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or the first ultra high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mol; and (C) 20 to 60 parts by weight, preferably 25 to 60 parts by weight, most preferred 35 to 55 parts by weight, of the second high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or the second ultra high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mol, wherein the molecular weight distribution of the multimodal polyethylene composition is from 10 to 60, preferably 10 to 25, preferably 10 to 20, determined by Gel Permeation Chromatography; the isothermal crystallization half-time of the multimodal polyethylene composition at a temperature of 123 C. is 7 min or less, preferably 6 min or less, preferably 2-6 min, according to Differential Scanning Calorimetry; and a spiral flow length at a temperature of 220 C. is at least 200 mm, preferably 250-400 mm.

8. The multimodal polyethylene composition according to claim 7, wherein the spiral flow length at a temperature of 220 C. is 250-370 mm.

9. The multimodal polyethylene composition according to claim 8, wherein the multimodal polyethylene composition has an weight average molecular weight (Mw) from 80,000 to 1,300,00 g/mol, preferably 80,000 to 250,000 g/mol, preferably 80,000 to 200,000 g/mol, measured by Gel Permeation Chromatography.

10. The multimodal polyethylene composition according to claim 7, wherein the multimodal polyethylene composition has a number average molecular weight (Mn) from 5,000 to 30,000 g/mol, preferably 5,000 to 25,000 g/mol, preferably 6,000 to 20,000 g/mol measured by Gel Permeation Chromatography.

11. The multimodal polyethylene composition according to claim 7, wherein the multimodal polyethylene composition has a Z average molecular weight (Mz) from 700,000 to 6,000,00 g/mol, preferably 700,000 to 2,500,000 g/mol, preferably 700,000 to 2,000,000 g/mol, more preferably 700,000 to 1,500,000 g/mol measured by Gel Permeation Chromatography.

12. The polyethylene composition according to claim 7, wherein the multimodal polyethylene composition has a density 0.950 to 0.965 g/cm3, preferably 0.953 to 0.960 g/cm3, according to ASTM D 1505 and/or MI.sub.2 from 0.1 to 20 g/10 min, preferably from 0.3 to 17 g/10 min, according to ASTM D 1238.

13. Screw cap comprising the multimodal polyethylene composition according to claim 7.

14. Screw cap according to claim 13 obtainable by injection molding or compression molding.

Description

EXPERIMENTAL AND EXAMPLES

[0097] Composition-Related Examples

[0098] The medium or high density polyethylene preparation was carried out in three reactors in series. Ethylene, hydrogen, hexane, catalyst and TEA (triethyl aluminum) co-catalyst were fed into a first reactor in the amounts shown in Table 1. A commercial available Ziegler-Natta catalyst was used. The catalyst preparation is for example described in Hungary patent application 0800771r. The polymerization in first reactor was carried out to make a low molecular weight polyethylene or medium molecular weight polyethylene. All of polymerized slurry polymer from first reactor was then transferred to a hydrogen removal unit to remove unreacted gas and some of hexane from polymer. The operating pressure in the hydrogen removal unit was be varied in a range of 100 to 115 kPa (abs) where residual hydrogen was removed more than 98% by weight but not more than 99.8% by weight from hexane before transferring to a second polymerization reactor. Some fresh hexane, ethylene and/or comonomer were fed into second reactor to produce first high molecular weight polyethylene (HMW1). All of polymerized polymer from second reactor was fed into the third reactor which produce second high molecular weight polyethylene (HMW2). Ethylene, comonomer, hexane and/or hydrogen were fed into the third reactor.

Comparative Example 1 (CE1)

[0099] A homopolymer was produced in first reactor to obtain a low molecular weight portion before transferring such polymer to hydrogen removal unit. Reactant mixture was introduced into the hydrogen removal unit to separate the unreacted mixture from the polymer. Residual hydrogen was removed 97.6% by weight when hydrogen removal unit was operated at pressure of 150 kPa (abs). The low molecular weight polymer was then transferred to the second reactor to produce a first high molecular weight polymer. Final, produced polymer from second reactor was transferred to the third reactor to create a second high molecular weight polymer. In third, a copolymerization was carried out by feeding 1-butene as a comonomer.

Example 1 (E1)

[0100] Example 1 was carried out in the same manner as Comparative Example 1 except that the hydrogen removal unit was operated at pressure of 115 kPa (abs). The residual of hydrogen from first reactor was removed 98.0% by weight. Characteristic properties of these multimodal polymers are shown in Table 2. As it can be seen, an improvement of stiffness-impact balance was observed when the percentage of removed hydrogen residual increased compared with the properties of Comparative Example 1.

Example 2 (E2)

[0101] Example 2 was carried out in the same manner as Comparative Example 1 except that the hydrogen removal unit was operated at pressure of 105 kPa (abs). The residual hydrogen from the first reactor was removed to an extend of 99.1% by weight. The operational of hydrogen removal unit under this pressure leads to an expansion of a polymer properties range. As seen in Table 2, a final melt flow rate of E2 was lower than a final melt flow rate of CE1 resulted in an improvement of Charpy impact while still maintained the flexural modulus.

Comparative Example 2 (CE2)

[0102] Comparative Example 2 was carried out in the same manner as Comparative Example 1 except that the hydrogen removal unit was operated at pressure of 102 kPa (abs). The residual of hydrogen from first reactor was removed to an extend of 99.9% by weight. The operational of hydrogen removal unit under this pressure leads to an expansion of a polymer properties range. As seen in Table 2, the final melt flow rate and a density of CE2 were quite similar to a final melt flow rate and a density of E2. A decay of Charpy impact was showed in CE2 compared to E2.

Comparative Example 3 (CE3)

[0103] A homopolymer was produced in a first reactor to obtain a low molecular weight portion before transferring the polymer to a hydrogen removal unit. Reactant mixture was introduced into the hydrogen removal unit to separate the unreacted mixture from the polymer. Hydrogen residual was removed to an extend of 97.9% by weight when hydrogen removal unit was operated at pressure of 150 kPa (abs). The low molecular weight polymer was then transferred to a second reactor to produce a first high molecular weight polymer. In the second reactor, a copolymerization was carried out by feeding 1-butene as a comonomer. Finally, in-situ bimodal copolymer from second reactor was transferred to a third reactor to create a second high molecular weight copolymer portion. Characteristic properties of this multimodal polymers is shown in Table 2. A significant improvement in Charpy impact at room temperature could be obtained by decreasing a density of final polymer when co-polymer was produced in both the second and the third reactor.

Example 3 (E3)

[0104] Example 3 was carried out in the same manner as Comparative Example 3 except that the hydrogen removal unit was operated at pressure of 105 kPa (abs). The residual of hydrogen from first reactor was removed to an extend of 98.8% by weight. The polymer obtained by this process operation had a melt flow rate of 0.195 g/10 min (5 kg loading) lower than such value obtained from CE3. As seen in Table 2, it revealed an improvement of stiffness-impact balance when the percentage of removed hydrogen residual increases compared with the properties of Comparative Example 3.

Example 4 (E4)

[0105] A homopolymer was produced in the first reactor to obtain a medium molecular weight portion before transferring such polymer to hydrogen removal unit. The hydrogen removal unit was operated at pressure of 105 kPa (abs) to separate the unreacted mixture from the polymer. The residual of hydrogen from first reactor was removed to an extend of 98.9% by weight. The medium molecular weight polymer was then transferred to the second reactor to produce a first ultra high molecular weight polymer. Finally, produced polymer from second reactor was transferred to the third reactor to create a second ultra high molecular weight polymer. The second and third reactors are operated under hydrogen depleted polyethylene polymerization. The processable in-situ ultra high molecular weight polyethylene is produced by this process operation leads to an excellent improvement of Charpy impact strength while still maintained the flexural modulus. The conventional UHMWPE with very high IV was known that it was unable to measured MI.sub.21. The inventive example E4 with IV of 9 dl/g shows good melt flow ability beyond the known art.

Example 6 (E6)

[0106] Example 6 was carried out in the same manner as Example 4 except that the comonomer feeding in the third ultra high molecular weight polyethylene. The polymer produced by this process leads to an excellent improvement of Charpy impact strength while still maintained the flexural modulus. As shown in table 2, the inventive example 6 with IV of 23 dl/g show the high impact strength (one notched impact without break) and flexural modulus as compared to comparative samples, however, the melt flow index is unmeasurable due to high viscosity and high Mw.

[0107] Screw Cap-Related Examples

[0108] The examples of polymer compositions for screw cap-related this invention regarding the multimodal polyethylenes were polymerized as shown in Table 1, 2, 3 and 4.

Comparative Example 4 (CE4)

[0109] A homopolymer was produced in first reactor to obtain a low molecular weight portion before transferring such polymer to hydrogen removal unit. Reactant mixture was introduced into the hydrogen removal unit to separate the unreacted mixture from the polymer. Residual hydrogen was removed 97.6% by weight when hydrogen removal unit was operated at pressure of 150 kPa (abs). The low molecular weight polymer was then transferred to the second reactor to produce a first high molecular weight polymer. Final, produced polymer from second reactor was transferred to the third reactor to create a second high molecular weight polymer. In third, a copolymerization was carried out by feeding 1-butene as a comonomer. As seen in Table 2 and 3, the final melt flow rate of CE4 were quite similar to a final melt flow rate of E5. A decay of charpy impact and flexural modulus were showed in CE4 compared to E5, even it showed lower density of E5.

Inventive Example 5 (E5)

[0110] Example 5 was carried out in the same manner as Comparative Example 4 except that the hydrogen removal unit was operated at pressure of 115 kPa (abs). The residual of hydrogen from first reactor was removed to an extend of 98.5% by weight. The polymer obtained by this process operation had a melt flow rate of 48 g/10 min (5 kg loading) lower than such value obtained from CE3. As seen in Table 2, it revealed an improvement of stiffness-impact balance when the percentage of removed hydrogen residual increases compared with the properties of Comparative Example 4.

[0111] The properties of the invention from inventive examples E5 were compared to the properties of comparative examples CE4.

Comparative Example 5 (CE5)

[0112] Comparative example 5 (CE5) is a bimodal polyethylene produced from Ziegler-Natta catalyst. The weight ratio between the ethylene homopolymer and the ethylene copolymer is in the range of 45:55 to 55:45. A polymer composition comprises a comonomer in an amount of at least 0.40 mol %.

Comparative Example 6 (CE6)

[0113] Comparative example 6 (CE6) is a commercial multimodal high density polyethylene Hostalen ACP5331 UVB plus.

Inventive Example 7 and 8 (E7 and E8)

[0114] Multimodal polyethylene compositions of inventive examples 7 and 8(E7 and E8) were produced according to the inventive process with the polymerization condition as shown in Table 3. The different weight fraction in each reactor was defined and 1-butene was applied as comonomer in the 2.sup.nd and 3.sup.rd reactor components. The properties of the invention from inventive examples 7 and 8 (E7 and E7) were compared to the properties of comparative examples 5 and 6 (CE5 and CE6).

[0115] The characteristics and properties of these multimodal polyethylenes are shown in Table 4. The comparisons between the multimodal polymers, but different polymerization process were illustrated. Surprisingly, the multimodal polyethylene according to this invention which contain higher Mz and higher shear thinning shows a significant improvement in processability and stiffness of inventive examples 7 and 8 (E7 and E8) compare to comparative examples 5 and 6 (CE5, CE6) and Inventive examples 5 (E5) compare to comparative example 4 (CE4), respectively.

[0116] The better processability can be investigated in term of both faster cycle time and higher flowability. Faster cycle time was determined by the lower crystallization haft time (ICHT) and higher crystal growth rate (K). The inventive examples 5, 7, and 8 (E5, E7 and E8) show lower ICHT and higher crystal growth rate (K) than comparative examples 4, 5 and 6 (CE4, CE5 and CE6). It is supposed that the ultra high molecular weight produced in the second component following the inventive process can act as a stem for easier nucleation resulting in faster crystallization rate. The flowability is normally determined by spiral flow length at temperature 220 C. The spiral flow length of inventive example E5 has higher than comparative example 4 (CE4), and inventive examples 7 and 8 (E7 and E8) have higher than comparative examples 5 and 6 (CE5 and CE6), even inventive examples have lower MI than comparative examples.

[0117] The improvement of stiffness compared to CE5 and CE6 were also investigated. The multimodal polyethylene composition of these invention examples 7 and 8 (E7 and E8) have better flexural modulus than comparative examples 5 and 6 (CE5 and CE6) and also the invention example 5 (E5) has higher flexural modulus than comparative examples (CE4). Because of the multimodal polyethylene according to this invention contain higher Mz shows a significant improvement in stiffness.

[0118] Moreover, the multimodal polyethylene according to this invention (E8) still has better stress cracking resistance as measured by FNCT compare to CE5 and CE6. Also the inventive example 7 (E7) showed equivalent FNCT to the bimodal polyethylene (CE5) even at higher density. This indicated that the inventive multimodal polyethylene composition provide better processability and higher stiffness with good balance to stress crack resistance beyond prior The invention enhanced significantly improvement of properties for screw cap and closure.

TABLE-US-00001 TABLE 1 Polymerization conditions of multimodal polyethylenes for Screw cap-related invention in lab reactor CE1 E1 E2 CE2 CE3 E3 E4 CE4 E5 E6 W.sub.A, % 55 55 55 55 45 45 30 50 50 30 W.sub.B, % 20 20 20 20 25 25 30 10 10 30 W.sub.C, % 25 25 25 25 30 30 40 40 40 40 First reactor Polymerization type Homo Homo Homo Homo Homo Homo Homo Homo Homo Homo Temperature, C. 80 80 80 80 80 80 80 80 80 80 Total pressure, kPa 800 800 800 800 800 800 800 800 800 800 Ethylene, g 1,100.72 1,100.70 1,100.86 1,100.74 900.30 900.30 540.50 725.21 725.57 485.70 Hydrogen, g 1.62 1.62 1.55 1.55 2.97 2.99 1.34 1.13 1.13 1.23 Hydrogen removal unit Pressure, kPa (abs) 150 115 105 102 150 105 105 150 115 105 Hydrogen remove, % 97.6 98.0 99.1 99.9 97.9 98.8 98.9 97.7 98.5 98.3 Second reactor Polymerization type Homo Homo Homo Homo Copo Copo Homo Copo Copo Homo Temperature, C. 70 70 70 70 70 70 70 80 80 70 Total pressure, kPa 250 250 250 250 250 250 400 300 300 400 Ethylene, g 400.52 400.81 400.35 400.06 500.17 500.31 540.36 145.35 145.21 485.78 Hydrogen, g 0 0 0 0 0 0 0 0 0 0 1-butene, g 0 0 0 0 18.84 18.91 0 8 8 0 Third reactor Polymerization type Copo Copo Copo Copo Copo Copo Homo Copo Copo Copo Temperature, C. 70 70 70 70 70 70 80 80 80 70 Total pressure, kPa 400 400 400 400 400 400 600 600 600 600 Ethylene, g 500.74 500.11 500.30 500.63 600.02 601.19 720.60 580.53 580.46 647.54 Hydrogen, g 0 0.001 0.001 0.001 0 0.001 0 0.59 1.37 0 1-butene, g 35.05 30.01 30.03 30.04 60.01 60.04 0 27 27 20.60 W.sub.A means percent by weight of Polymer in the first reactor W.sub.B means percent by weight of Polymer in the second reactor W.sub.C means percent by weight of Polymer in the third reactor

TABLE-US-00002 TABLE 2 CE1 E1 E2 CE2 CE3 E3 Powder MI.sub.5, g/10 min 0.474 0.372 0.240 0.242 0.275 0.200 MI.sub.21, g/10 min 13.83 10.80 7.38 7.23 6.40 4.81 Density, g/cm.sup.3 0.9565 0.9578 0.9555 0.9567 0.9441 0.9438 IV, dl/g Mw 276,413 244,279 291,295 319,487 252,160 306,468 Mn 8,877 8,724 8,843 8,472 8,016 7,637 Mz 2,788,607 2,370,678 3,401,041 4,135,007 1,638,224 2,643,953 PDI 31 28 33 38 31 40 Pellet MI.sub.5, g/10 min 0.436 0.410 0.232 0.199 0.298 0.195 MI.sub.21, g/10 min 14.46 11.68 7.876 6.696 7.485 4.604 Density, g/cm.sup.3 0.9577 0.9574 0.9568 0.9566 0.9442 0.9440 IV, dl/g 2.97 3.03 3.52 3.64 3.12 3.37 % Crystalinity, % 64.70 67.24 64.78 66.16 57.49 54.05 Charpy, 23 C., 23.5 29.9 35.3 30.5 47.9 50.9 kJ/m.sup.2 Flexural modulus, 1,130 1,210 1,123 1,123 727 785 MPa E4 CE4 E5 E6 Powder MI.sub.5, g/10 min 54.80 48.07 NA MI.sub.21, g/10 min 0.145 641 653 NA Density, g/cm.sup.3 0.9534 0.9606 0.9590 0.9409 IV, dl/g 9.00 1.07 1.06 23 Mw 868,813 77,334 91,752 1,269,336 Mn 24,107 5,400 6,035 23,450 Mz 5,112,060 667,276 1,027,956 5,262,195 PDI 36 14 15 54.13 Pellet MI.sub.5, g/10 min 60.62 55.47 MI.sub.21, g/10 min 713.1 752.2 Density, g/cm.sup.3 0.9608 0.9594 IV, dl/g 9.00 1.0 1.1 23 % Crystallinity, % 68.23 69.52 65.64 58.20 Charpy, 23 C., 84.4 1.5 1.8 85.41 kJ/m.sup.2 Flexural modulus, 1,109 1,147 1,196 890 MPa

TABLE-US-00003 TABLE 3 Polymerization conditions of multimodal polyethylenes for Screw cap-related invention from pilot scale E7 E8 Process Parameters Unit (Inventive) (Inventive) 1.sup.st Reactor Split ratio % 58-62 48-52 Temperature ( C.) 81-85 81-85 Pressure Bar 5.5-6.0 4.5-5.0 Hexane flow rate L/h 90.0 63.0 Ethylene flow rate L/h 2310.5 1918.0 Hydrogen flow rate NL/h 188.1 104.336 Catalyst flow rate g/h 3.2 3.1 2.sup.nd Reactor Split ratio % 9-10 12-18 Temperature ( C.) 68-70 68-70 Pressure Bar 1.5-3.0 1.5-3.0 Hexane flow rate L/h 176.2 148.7 Ethylene flow rate L/h 1051.0 1354 Hydrogen flow rate NL/h 0 0 Comonomer/Ethylene Feed 0.0037 0.00239 H.sub.2 removal 98.89 98.99 Flash pressure 0.054 0.056 Comonomer type 1-Butene 1-Butene 3.sup.rd Reactor Split ratio % 28-33 32-38 Temperature ( C.) 70-75 70-75 Pressure Bar 1.5-3.0 1.5-3.0 Hexane flow rate L/h 191.6 164.0 Ethylene flow rate L/h 1980.2 1969.3 Hydrogen flow rate NL/h 39.8 0 Comonomer/Ethylene Feed 0.002 0.00849 Production rate kg/h 30.0 25.0 Comonomer type 1-Butene 1-Butene

TABLE-US-00004 TABLE 4 Polymer compositions and properties of multimodal polyethylenees (pellet) for Screw cap-related invention E5 CE4 E7 E8 CE5 CE6 Properties Inventive Comparative Inventive Inventive Comparative Comparative MI.sub.2 [g/10 min] 14.6 16.8 0.8 0.5 0.9 2.0 MI.sub.5 [g/10 min] 55.47 60.62 3.16 2.12 3.61 6.54 Density [g/cm.sup.3] 0.9594 0.9608 0.9603 0.9582 0.9584 0.9574 IV [cm.sup.3/g] 1.10 1.01 2.01 2.39 1.98 1.12 Mn [g/mol] 6,065 7,036 9,600 9,393 8,847 13,459 Mw [g/mol] 85,150 81,171 174,712 183,319 157,896 119,848 Mz [g/mol] 713,636 677,966 1,359,161 1,436,240 1,058,549 765,341 PDI 14 12 18 20 18 9 Comonomer content 0.83 0.67 0.43 0.52 0.50 0.36 [% mol] ICHT @ 123 C. [min] 3.1 3.2 4.1 6.1 8.2 8.7 Crystal growth rate 1.68E05 1.19E05 2.7E06 1.21E06 1.4E07 5.8E07 constant (K) Tm [ C.] 130 130 130 129 130 130 Tc [ C.] 118 118 119 118 117 117 % Crystallinity 66 66 73 66 69 67 SHI (1/100) 12.2 7.0 23.4 26.1 11.4 3.9 .sub.0.01 [Pa .Math. s] 2,176 1,283 27,870 38,907 20,343 6,873 Spiral flow length @ 350 340 293 282 266 238 220 C. [mm] Flexural modulus 1,196 1,147 1,251 1,258 1,157 1,141 (ISO 178) [MPa] FNCT (ISO 16770) N/A N/A 17 22 18 8 @ 50 C., 6 MPa, 2% wt Arkopal [hr]