POLYALPHAOLEFIN HAVING UNIFORM STRUCTURE AND METHOD OF PREPARING SAME

Abstract

The present invention relates to a polyalphaolefin having a uniform structure and a method of preparing the same, and more particularly to a method of preparing polyalphaolefin having a uniform comb-like structure by minimizing the formation of short chain branches, which deteriorate the properties of lubricant base oil, using a homogeneous single-active-site metallocene catalyst, an organometallic compound cocatalyst and an organoboron compound promoter.

Claims

1. A polyalphaolefin, which is a hydrogenated polyalphaolefin composition comprising at least one hydrogenated alphaolefin oligomer, the polyalphaolefin having a weight average molecular weight (Mw) of 15,000 or less and a molecular weight distribution (Mw/Mn) of 2.0 or less and satisfying Expression (1) below:
End carbon/carbon2.7(1) wherein an end carbon/ carbon ratio represents a relative ratio of integrals at 14 to 16 ppm and 40 to 42 ppm in a .sup.13C NMR spectrum.

2. The polyalphaolefin of claim 1, satisfying Expression (2) below.
1.3End carbon/carbon2.7(2)

3. The polyalphaolefin of claim 1, satisfying Expression (3) below.
1.3End carbon/carbon1.7(3)

4. The polyalphaolefin of claim 1, wherein the polyalphaolefin has a kinematic viscosity at 100 C. of 200 cSt or less.

5. The polyalphaolefin of claim 1, wherein the polyalphaolefin has a pour point of 35 C. or less and a flash point of 230 C. or more.

6. The polyalphaolefin of claim 1, wherein the polyalphaolefin has a residual metal content of 5 ppm or less.

7. The polyalphaolefin of claim 1, wherein the polyalphaolefin is prepared by polymerizing a C6-C20 alphaolefin using a catalyst composition comprising a metallocene compound, an organometallic compound and an organoboron compound.

8. The polyalphaolefin of claim 7, wherein the alphaolefin is any one or a mixture of two or more selected from the group consisting of 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tricene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene and 1-eicosene.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0042] FIG. 1 shows the structure of polyalphaolefin prepared through a conventional method and the structure of polyalphaolefin prepared according to an embodiment of the present invention; and

[0043] FIG. 2 is a graph showing the NMR spectrum of the polyalphaolefin prepared according to an embodiment of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS

[0044] Hereinafter, a detailed description will be given of the preferred embodiments of the present invention. However, the present invention is not limited to these embodiments, but may be modified in other forms. These embodiments are provided in order to fully convey the spirit of the present invention to those skilled in the art so that the contents introduced herein are thorough and complete.

Examples 1 to 8 and Comparative Examples 1 to 5: Preparation of Polyalphaolefin

Example 1

[0045] 1. Preparation of Catalyst Solution

[0046] 200 ml of a catalyst solution was prepared by mixing 0.3 mmol of dimethylsilylene bis(tetrahydroindenyl) zirconium dichloride, 0.35 mmol of N,N-dimethylanilinium tetrapentafluorophenylboron, 20 mmol of triisobutylaluminum and toluene in a nitrogen-purged glass flask.

[0047] 2. Polymerization

[0048] 1100 ml of 1-octene was placed in a nitrogen-purged stainless steel autoclave, the temperature of the reaction system was elevated to 79 C., and then 30 ml of the catalyst solution prepared above was added thereto. Subsequently, 200 g/hr of 1-octene, 50 g/hr of hexane and 0.3 ml/min of the catalyst solution were continuously fed and polymerization was initiated with stirring at 1600 rpm. Thereafter, a temperature of 79 C. and a pressure of 6 KG were maintained to afford a polymer. Thereafter, the polymer solution thus obtained was discharged continuously through a back-pressure regulator and mixed with a 1 M sodium hydroxide aqueous solution to thus deactivate the same.

[0049] 3. Treatment after Polymerization

[0050] The sodium hydroxide aqueous solution was removed from the mixture of the polymer solution and the sodium hydroxide aqueous solution, after which the impurities in the polymer solution were extracted using distilled water and removed. Next, the polymer solution was concentrated for 30 min at 100 C. under reduced pressure and dried for 30 min at 240 C. under reduced pressure, after which heavy oligomers, from which unreacted monomers and low-molecular-weight oligomers were removed, were hydrogenated, yielding a polyalphaolefin.

Examples 2 to 5

[0051] Polyalphaolefins were prepared in the same manner as in Example 1, with the exception that the reaction temperature during the polymerization was changed as shown in Table 1 below.

Example 6

[0052] A polyalphaolefin was prepared in the same manner as in Example 1, with the exception that the polymerization was performed using 1-decene at a polymerization temperature of 68 C.

Example 7

[0053] A polyalphaolefin was prepared in the same manner as in Example 1, with the exception that the polymerization was performed using a mixture of 80 wt % of 1-octene and 20 wt % of 1-hexene at a polymerization temperature of 69 C.

Example 8

[0054] A polyalphaolefin was prepared in the same manner as in Example 1, with the exception that the polymerization was performed using a mixture of 80 wt % of 1-octene and 20 wt % of 1-decene at a polymerization temperature of 69 C.

Comparative Examples 1 to 5

[0055] Polyalphaolefins were prepared in the same manner as in Example 1, with the exception that the reaction temperature during the polymerization was changed as shown in Table 1 below.

TABLE-US-00001 TABLE 1 Reaction Material temperature used ( C.) Example 1 1-octene 85 Example 2 1-octene 72 Example 3 1-octene 66 Example 4 1-octene 61 Example 5 1-octene 57 Example 6 1-decene 68 Example 7 80 wt % of 69 1-octene and 20 wt % of 1-hexene Example 8 80 wt % of 69 1-octene and 20 wt % of 1-hexene Comparative 1-octene 105 Example 1 Comparative 1-octene 95 Example 2 Comparative 1-octene 43 Example 3 Comparative 1-octene 41 Example 4 Comparative 1-octene 38 Example 5

Evaluation Example 1: Evaluation of Properties

[0056] The properties of the polyalphaolefins prepared in Examples 1 to 8 and Comparative Examples 1 to 5 were measured through the following methods. The results are shown in Table 2 below.

Evaluation Example 1-1: Molecular Weight Distribution

[0057] Molecular weight distribution was measured using GPC (VE2001, Viscotek). Upon GPC measurement, a PLgel 5 m Mixed-D column having an inner diameter of 7.5 mm and a length of 300 mm was used, the measurement temperature was 35 C., and the mobile phase was tetrahydrofuran (THF, Burdick and Jackson, HPLC grade). The mobile phase was supplied at a rate of 1 ml/min, the sample concentration was 9.26 wt %, and the amount of the sample that was added was about 100 m. A differential refractometer was used as a detector, and the peaks were separated by data processor OmniSEC 4.6 (manufactured by Viscotek).

Evaluation Example 1-2. Kinematic Viscosity of Polymer at 100 C.

[0058] The kinematic viscosity at 100 C. was measured in accordance with ASTM D 445 using Lauda PV15, Japan.

Evaluation Example 1-3. Viscosity Index

[0059] The viscosity index was measured in accordance with ASTM D 2270.

Evaluation Example 1-4. Pour Point

[0060] The low-temperature pour point was measured in accordance with ASTM D 6749 using a Tanaka Science MPC 102L, Japan (oil temperature: 40 C.).

Evaluation Example 1-5. Flash Point

[0061] The flash point was measured through a Cleveland open-cup method in accordance with ASTM D 92.

Evaluation Example 1-6. End Carbon/ Carbon Ratio

[0062] .sup.13C NMR was measured at room temperature using an AVANCE III 500 MHz NMR spectrometer equipped with a BBO probe, made by Bruker. All spectra were processed and visualized using Topspin 2.1 (an NMR program from Bruker).

[0063] Specifically, inverse gated decoupling pulses were used as a pulse program for quantitative analysis. In the pulse program, the relaxation delay time was 10 sec, the free induction decay acquisition time was 0.8 sec, and the S/N (signal to noise) value was 1,000 or more. The measured .sup.13C NMR spectrum showed the end carbon/a carbon ratio as the relative ratio of integrals at 40 to 42 ppm for a carbon and 14 to 16 ppm for end carbon based on chloroform (77 ppm).

Evaluation Example 1-7. Bromine Index

[0064] The bromine index was measured in accordance with ASTM D1559.

Evaluation Example 1-8. Metal Content

[0065] The concentration of the metal component in the polyalphaolefin was analyzed through ICP (Inductively Coupled Plasma) spectroscopy.

TABLE-US-00002 TABLE 2 Molecular weight Kinematic Pour Flash End Metal distribution viscosity at Viscosity point point carbon/ Bromine Yield content (Mw/Mn) 100 C. (cSt) index ( C.) ( C.) carbon index (%) (ppm) Example 1 1.2 10 146 57 or 246 2.65 0.1 or 85 5 or less less less Example 2 1.5 40 170 45 266 1.62 0.1 or 87 5 or less less Example 3 1.53 65 181 42 270 1.47 0.1 or 89 5 or less less Example 4 1.62 100 193 39 270 1.38 0.1 or 90 5 or less less Example 5 1.7 150 205 37 276 1.32 0.1 or 87 5 or less less Example 6 1.46 38.3 182 42 278 1.58 0.1 or 90 5 or less less Example 7 1.46 38.1 163 48 272 1.45 0.1 or 89 5 or less less Example 8 1.48 38.5 173 49 276 1.46 0.1 or 88 5 or less less Comparative 1.09 4 127 60 or 222 9.21 0.1 or 40 5 or less Example 1 less less Comparative 1.18 6 146 60 or 228 4.56 0.1 or 60 5 or less Example 2 less less Comparative 2.02 300 235 32 293 1.25 0.1 or 90 5 or less Example 3 less Comparative 2.09 350 242 1.24 0.1 or 89 5 or less Example 4 less Comparative 2.1 450 248 1.1 0.1 or 90 5 or less Example 5 less

[0066] As is apparent from Table 2, the polyalphaolefins prepared in Examples 1 to 5 exhibited an end carbon/a carbon ratio of 2.7 or less compared to Comparative Examples 1 and 2. Moreover, in the case of polyalphaolefins prepared in Examples 6 to 8 using different kinds of single alphaolefin or various alphaolefin mixtures, it was confirmed that the end carbon/a carbon ratio was superior, as in Example 1 to 5. Accordingly, the polyalphaolefins of Examples 1 to 8 were found to suppress the formation of short chain branches compared to Comparative Examples 1 and 2.

[0067] In the case of the polyalphaolefins prepared in Comparative Examples 3 to 5, the end carbon/a carbon ratio was superior, but the kinematic viscosity and pour point were found to be very large compared to Examples 1 to 8. Accordingly, the polyalphaolefins of Comparative Examples 3 to 5 were found to be unsuitable for use as lubricants because of the very low fluidity thereof.

[0068] Moreover, it can be confirmed that the polyalphaolefins prepared in Examples 1 to 8 have almost no residual unsaturated double bonds because bromine numbers thereof are 0.1 or less, indicative of high chemical stability, thereby preventing the formation of foreign substances and yellowing.

[0069] In addition, it can be confirmed that the polyalphaolefins prepared in Examples 1 to 8 have a metal content of 5 ppm or less, indicating that there is almost no residual metal, thereby preventing deterioration of product quality.

[0070] Although preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications are possible without departing from the scope and spirit of the invention as disclosed in the accompanying claims, and such modifications should not be understood separately from the technical ideas or essential characteristics of the present invention.